An Uplifting Discussion of T-Duality

It is well known that string theory has a T-duality symmetry relating circle compactifications of large and small radius. This symmetry plays a foundational role in string theory. We note here that while T-duality is order two acting on the moduli space of compactifications, it is order four in its action on the conformal field theory state space. More generally, involutions in the Weyl group $W(G)$ which act at points of enhanced $G$ symmetry have canonical lifts to order four elements of $G$, a phenomenon first investigated by J. Tits in the mathematical literature on Lie groups and generalized here to conformal field theory. This simple fact has a number of interesting consequences. One consequence is a reevaluation of a mod two condition appearing in asymmetric orbifold constructions. We also briefly discuss the implications for the idea that T-duality and its generalizations should be thought of as discrete gauge symmetries in spacetime.Comment: 47 pages, claims regarding $Z_4$ valued cocycles remove

D0-brane tension in string field theory

We compute the D0-brane tension in string field theory by representing it as a tachyon lump of the D1-brane compactified on a circle of radius $R$. To this aim, we calculate the lump solution in level truncation up to level L=8. The normalized D0-brane tension is independent on $R$. The compactification radius is therefore chosen in order to cancel the subleading correction $1/L^2$. We show that an optimal radius $R^*$ indeed exists and that at $R^*$ the theoretical prediction for the tension is reproduced at the level of $10^{-5}$. As a byproduct of our calculation we also discuss the determination of the marginal tachyon field at $R\to 1$.Comment: 13 pages, 3 Eps figure

Minimax studies

Effect of nonzero initial conditions on selection of minimax controllers for large launch vehicles and extremal bounded amplitude bounded rate inputs to linear system

Design of hydraulic output Stirling engine

A hydraulic output system for the RE-1000 free piston stirling engine (FPSE) was designed. The hydraulic output system can be readily integrated with the existing hot section of RE-1000 FPSE. The system has two simply supported diaphragms which separate the engine gas from the hydraulic fluid, a dynamic balance mechanism, and a novel, null center band hydraulic pump. The diaphragms are designed to endure more than 10 billion cycles, and to withstand the differential pressure load as high as 14 MPa. The projected thermodynamic performance of the hydraulic output version of RE-1000 FPSE is 1.87 kW at 29/7 percent brake efficiency

Solar cycle variation in Sun-as-a-star Ca II 854.2 nm bisectors

The bisector of the strong chromospheric Ca II 854.2 nm line has an inverse-C shape the cause of which is not yet fully understood. We show that the amplitude of the bisector in Sun-as-a-star observations exhibits a solar cycle variation with smaller amplitudes during highest activity. The line core intensity is lower during solar minima while the part of the bisector most sensitive to the line core shows no systematic change with activity. Our results support the use of Ca II 854.2 nm bisectors in studying the relationship between convection and magnetic fields, not only in the Sun but in other stars as well.Comment: Accepted to Ap

Design and preliminary test results at Mach 5 of an axisymmetric slotted sound shield

The basic theory and sound attenuation mechanisms, the design procedures, and preliminary experimental results are presented for a small axisymmetric sound shield for supersonic wind tunnels. The shield consists of an array of small diameter rods aligned nearly parallel to the entrance flow with small gaps between the rods for boundary layer suction. Results show that at the lowest test Reynolds number (based on rod diameter) of 52,000 the noise shield reduced the test section noise by about 60 percent ( or 8 db attenuation) but no attenuation was measured for the higher range of test reynolds numbers from 73,000 to 190,000. These results are below expectations based on data reported elsewhere on a flat sound shield model. The smaller attenuation from the present tests is attributed to insufficient suction at the gaps to prevent feedback of vacuum manifold noise into the shielded test flow and to insufficient suction to prevent transition of the rod boundary layers to turbulent flow at the higher Reynolds numbers. Schlieren photographs of the flow are shown

Kekalahan Partai Koalisi Merah Putih pada Pemilu Presiden dan Wakil Presiden Republik Indonesia Tahun 2014 di Kecamatan Logas Tanah Darat Kabupaten Kuantan Singingi

In 1945 Article 6A Paragraph 2 Candidate Pair of President and Vice Presidentshall be nominated by a Political Party or a coalition of political parties prior to theGeneral Election General Election. In this case the electoral system is an importantfactor. Therefore, the authors intend to conduct research with the aim to explain thedefeat of the Coalition Party Red and White in the election of President and VicePresident of the Republic of Indonesia in 2014 in the district of the Land Army LogasRegency Kuantan Singingi and the factors that influence it.The location of this research is the District Land Army Logas Singingi RegencyKuantan. This study includes qualitative research, with data collection techniquesinterview, documentation, and research informants determined by purposive samplingtechnique. In this study, the theory used is derived from the theory proposed byNazuruddin Sjamsuddin, Zukifli Hamid, Personal Toto, H.Anto Djawamaku, and JamesBuchanan regarding the cause of divisions and conflicts within the political parties andcoalitions of parties. Results of this study concluded that the defeat of the CoalitionParty Red and White in the election of President and Vice President of the Republic ofIndonesia in 2014 in the district of the Land Army Logas Regency Kuantan Singingidue to a lack of coordination elite and elite coalition center coalition led to overlappingareas of interest between the central elite with elite area, lack of campaign funds,discriminatory policies and voters focused imaging media.Keywords: Presidential Election, The Coalition Red and Whit