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

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

PENGARUH BIOURINE SAPI TERHADAP PERTUMBUHAN BIBIT KARET (Hevea brasiliensis Mull. Arg) ASAL STUM MATA TIDUR (The Effect of Cattle Biourine to The Growth of Rubber Seedling from Stum Rubber)

The objective of this research was to determine the best biourine concentration on the rubber seedling. This research was conducted at Teaching and Research Farm, Agriculture Faculty, Mendalo Darat, Jambi. This experiment was designed using completely Randomized Design with five treatment, and three replications. The treatments were  the level of biourine concentration : uo= 0% bio-urine, u1= 2,5%, u2= 5,0%, u3= 7,5% dan u4= 10,0%. Three were 15 units of treatments. Statical analysis showed that cattle biourine  at  7, 5 % gave the best growth of rubber seedling, shoot height and root dry weight. Key word: Urine , rubber, shoo

EFFECT OF GEOMETRIC CONFIGURATIONS ON HYDRODYNAMIC PERFORMANCE ASSESSMENT OF A MARINE PROPELLER

The present paper deals with the effect of the geometric characteristics on the propeller hydrodynamic performances. Several propeller configurations are created by changing number of blades, expanded area and pitch ratios. The Reynolds-Averaged Navier-Stokes (RANS) equations are solved using the commercial code FLUENT 6.3.26. The standar

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

Analisis Hubungan Pendapatan Asli Daerah, Dana Alokasi Umum, dan Dana Alokasi Khusus Atas Belanja Modal pada Pemerintah Daerah Kabupaten Tolitoli Provinsi Sulawesi Tengah

Local governments need to increase capital investment in fixed assets, such as: equipments, buildings, infrastructures, and other fixed assets. Capital expenditure allocation was based on the local needs for facilities and infrastructure. The higher level of capital investment expected to improve the quality of public services, because the fixed assets due to capital expenditure is a key for the implementation of governmental duties and provides services to the public.This study was aimed at analyzing the corelations of local own revenues, general allocation funds, and specific allocation funds with capital expenditures at Tolitoli Regency in Central Sulawesi Province. Research design methods is the field research by correlation analysis.Test results showed a lack relationship between local own revenues with capital expenditures by R value was 0,155. Meanwhile the relationship between general allocation funds with capital expenditures was 0,981 and special allocation funds with capital expenditures was 0,427. It shows the close relationship between the two variables with capital expenditures

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

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