The Casimir Effect in Spheroidal Geometries

We study the zero point energy of massless scalar and vector fields subject to spheroidal boundary conditions. For massless scalar fields and small ellipticity the zero-point energy can be found using both zeta function and Green's function methods. The result agrees with the conjecture that the zero point energy for a boundary remains constant under small deformations of the boundary that preserve volume (the boundary deformation conjecture), formulated in the case of an elliptic-cylindrical boundary. In the case of massless vector fields, an exact solution is not possible. We show that a zonal approximation disagrees with the result of the boundary deformation conjecture. Applying our results to the MIT bag model, we find that the zero point energy of the bag should stabilize the bag against deformations from a spherical shape.Comment: 24 pages, 3 figures. To appear in Phys. Rev.

A combined NMR and DFT study of Narrow Gap Semiconductors: The case of PbTe

In this study we present an alternative approach to separating contributions to the NMR shift originating from the Knight shift and chemical shielding by a combination of experimental solid-state NMR results and ab initio calculations. The chemical and Knight shifts are normally distinguished through detailed studies of the resonance frequency as function of temperature and carrier concentration, followed by extrapolation of the shift to zero carrier concentration. This approach is time-consuming and requires studies of multiple samples. Here, we analyzed $^{207}$Pb and $^{125}$Te NMR spin-lattice relaxation rates and NMR shifts for bulk and nanoscale PbTe. The shifts are compared with calculations of the $^{207}$Pb and $^{125}$Te chemical shift resonances to determine the chemical shift at zero charge carrier concentration. The results are in good agreement with literature values from carrier concentration-dependent studies. The measurements are also compared to literature reports of the $^{207}$Pb and $^{125}$Te Knight shifts of $n$- and $p$-type PbTe semiconductors. The literature data have been converted to the currently accepted shift scale. We also provide possible evidence for the "self-cleaning effect" property of PbTe nanocrystals whereby defects are removed from the core of the particles, while preserving the crystal structure.Comment: 34 pages, 9 figure

Realistic constraints on the doubly charged bilepton couplings from Bhabha scattering with LEP data

Upper limits on doubly charged bilepton couplings and masses are extracted from LEP data for Bhabha scattering at energy range $\sqrt{s}=183-202$ GeV using standard model program ZFITTER which calculates radiative corrections. We find that $g_{L}^{2}/M_{L}^{2}<O(10^{-5})GeV^{-2}$ at 95% C.L. for scalar and vector bileptons.Comment: 5 pages, 1 EPS figur

Tinjauan Momen Lentur Pelat Dua Arah Dengan Metode Perencanaan Langsung Dan Metode Elemen Hingga

This research conducted to study and determine the bending moment plate by using the DirectDesign Method and Finite Element Method. In the procedure of calculation of concrete structuresfor buildings, namely SNI 2847 2013 has been set up several plates planning methods one ofwhich is a method of using the Direct Design Method analysis. Finite element method (FEM) isdividing a complex problem into small elements where a simpler solution can be easily obtained.The theory used in plate analysis with the FEM is Kirchhoff-Love theory in which the limits areused specifically for the analysis of thin plates with small deflections by ignoring the transverseshear forces. The program is used by applying the Finite Element Method in this study is aMicrosoft Excel as a tool for calculations and modeling program SAP 2000 as a plate structure.From the calculations that the value of deflection and the bending moment on the plate twodirections with varying results.From the results obtained show that the static moments of totalfactored Direct Planning Method and the Finite Element Method showed results equal to eachother . Distribution moments on the foundation and interior plate field differently due to directPlanning Method using a great moment coefficients in pedestal while the Finite Element Methodusing transition stiffness matri

Four Fermion Processes at Future e+e−e^+e^- Colliders as a Probe of New Resonant Structures

Possible oblique effects from vector particles that are strongly coupled to the known gauge bosons are calculated for the case of final hadronic states produced at future $e^+e^-$ colliders, using a formalism that was recently proposed and that exploits the information and the constraints provided by LEP 1 results. Combining the hadronic channels with the previously analysed leptonic ones we derive improved limits for the masses of the resonances that,in technicolour-like cases, would range from one to two TeV for a 500 GeV linear collider, depending on the assumed theoretical constraints.Comment: 11 pages, postscript file of 3 figures appended at the end of the latex file PM/93-34 UTS-DFT-93-2

Minimal Absorption Measurements

We show that it is not possible to discriminate two close transparencies without a certain number of photons being absorbed. We extend this to the discrimination of patterns of transparency (images).Comment: 11 pages (latex

Kemampuan Fitoremediasi Salvinia Molesta D. S. Mitchell pada Beberapa Konsentrasi Limbah Cair Minyak Bumi

Penelitian tentang Kemampuan Fitoremediasi Salvinia molesta D.S. Mitchell pada Bebera-pa Konsentrasi Limbah Cair Minyak Bumi telah dilaksanakan pada Mei sampai Juni 2011. Tujuan penelitian ini untuk mengetahui kemampuan fitoremediasi S. molesta pada beberapa konsentrasi limbah cair minyak bumi dengan mengukur TPH (Total Petroleum Hidrokarbon), pH dan berat basah. Penelitian ini dilakukan dengan menggunakan Rancangan Acak Lengkap (RAL) dengan perlakuan konsentrasi limbah 0%, 15%, 30%, 45%, 60% dan 75%, dan masing-masing perlakuan diulang 4 kali. Hasil penelitian menunjukkan bahwa S. molesta mampu menurunkan TPH pada tiap perlakuan konsentrasi limbah cair minyak bumi, dengan penurunan TPH tertinggi diperoleh pada konsentrasi limbah 75%, yaitu sebesar 1317 ppm. Pada fitoremediasi limbah cair minyak bumi menggunakan S. molesta terjadi penurunan pH yang stabil. Pertumbuhan S. molesta yang tepat pada fitoremediasi limbah cair minyak bumi diperoleh pada konsentrasi limbah 60%, dengan per-tambahan berat basah selama 30 hari sebesar 68,85 g. Dari hasil yang diperoleh, dapat disimpul-kan bahwa konsentrasi limbah cair minyak bumi yang tepat untuk proses fitoremediasi dan per-tumbuhan S. molesta diperoleh pada konsentrasi limbah 60%, dengan penurunan TPH 1157 ppm

Pseudo Goldstones at Future Colliders from the Extended Bess Model

We consider the production of the lightest pseudo-Goldstone bosons at future colliders through the vector resonances predicted by the extended BESS model, which consists of an effective lagrangian parametrization with dynamical symmetry breaking, describing scalar, vector and axial-vector bound states in a rather general framework. We find that the detection of pseudo-Goldstone pairs at LHC requires a careful evaluation of backgrounds. For e+e- collisions in the TeV range the backgrounds can be easily reduced and the detection of pseudo-Goldstone pairs is generally easier.Comment: 17 pages and 12 figures (included as a uuencoded tar file), LaTeX (style article), UGVA-DPT 1994/03-84

The potential use of service-oriented infrastructure framework to enable transparent vertical scalability of cloud computing infrastructure

Cloud computing technology has become familiar to most Internet users. Subsequently, there has been an increased growth in the use of cloud computing, including Infrastructure as a Service (IaaS). To ensure that IaaS can easily meet the growing demand, IaaS providers usually increase the capacity of their facilities in a vertical IaaS increase capability and the capacity for local IaaS amenities such as increasing the number of servers, storage and network bandwidth. However, at the same time, horizontal scalability is sometimes not enough and requires additional strategies to ensure that the large number of IaaS service requests can be met. Therefore, strategies requiring horizontal scalability are more complex than the vertical scalability strategies because they involve the interaction of more than one facility at different service centers. To reduce the complexity of the implementation of the horizontal scalability of the IaaS infrastructures, the use of a technology service oriented infrastructure is recommended to ensure that the interaction between two or more different service centers can be done more simply and easily even though it is likely to involve a wide range of communication technologies and different cloud computing management. This is because the service oriented infrastructure acts as a middle man that translates and processes interactions and protocols of different cloud computing infrastructures without the modification of the complex to ensure horizontal scalability can be run easily and smoothly. This paper presents the potential of using a service-oriented infrastructure framework to enable transparent vertical scalability of cloud computing infrastructures by adapting three projects in this research: SLA@SOI consortium, Open Cloud Computing Interface (OCCI), and OpenStack