Further development of a charged liquid colloid source for electrostatic propulsion Final report

Performance characteristics of charged liquid droplet electrostatic propulsion syste

Analisa dan Perancangan Jaringan Private Cloud Computing Berbasis Web Eyeos

— Private Cloud Computing is the model of Cloud Computing that provides a smaller scope to be able to provide certain services to specific users on an Enterprise scale companies. Expension of the company at Sutindo Raya Mulia, PT will add new employees and new computer devices and their software application that has a license. It will lead to the use of base servers load in the company. In the Cloud Computing system base servers, local no longer has to do all the heavy load when used for all resource servers cloud computing will be the one using openstack. Openstack is a cloud OS that manages the resource for function of compute, storage, network, and can be implemented for the characteristics of Infrastructure as a Service (IAAS). OpenStack can be built through the virtual server instance for eyeOS as one of cloud computing services Software As A Service (SAAS). Computer users simply install the browser on their computer can already implement in the company by using the eyeOS

Comment on ``Capacity of the Hopfield model''

In a recent paper ``The capacity of the Hopfield model, J. Feng and B. Tirozzi claim to prove rigorous results on the storage capacity that are in conflict with the predictions of the replica approach. We show that their results are in error and that their approach, even when the worst mistakes are corrected, is not giving any mathematically rigorous results.Comment: 4pp, Plain Te

The structure of one-relator relative presentations and their centres

Suppose that G is a nontrivial torsion-free group and w is a word in the alphabet G\cup\{x_1^{\pm1},...,x_n^{\pm1}\} such that the word w' obtained from w by erasing all letters belonging to G is not a proper power in the free group F(x_1,...,x_n). We show how to reduce the study of the relative presentation \^G= to the case n=1. It turns out that an "n-variable" group \^G can be constructed from similar "one-variable" groups using an explicit construction similar to wreath product. As an illustration, we prove that, for n>1, the centre of \^G is always trivial. For n=1, the centre of \^G is also almost always trivial; there are several exceptions, and all of them are known.Comment: 15 pages. A Russian version of this paper is at http://mech.math.msu.su/department/algebra/staff/klyachko/papers.htm . V4: the intoduction is rewritten; Section 1 is extended; a short introduction to Secton 5 is added; some misprints are corrected and some cosmetic improvements are mad

Comment on ``High Temperature Fermion Propagator -- Resummation and Gauge Dependence of the Damping Rate''

Baier et al. have reported the damping rate of long-wavelength fermionic excitations in high-temperature QED and QCD to be gauge-fixing-dependent even within the resummation scheme due to Braaten and Pisarski. It is shown that this problem is caused by the singular nature of the on-shell expansion of the fermion self-energy in the infra-red. Its regularization reveals that the alleged gauge dependence pertains to the residue rather than the pole of the fermion propagator, so that in particular the damping constant comes out gauge-independent, as it should.Comment: 5 page

Measurements and Simulation Studies of Piezoceramics for Acoustic Particle Detection

Calibration sources are an indispensable tool for all detectors. In acoustic particle detection the goal of a calibration source is to mimic neutrino signatures as expected from hadronic cascades. A simple and promising method for the emulation of neutrino signals are piezo ceramics. We will present results of measruements and simulations on these piezo ceramics.Comment: 5 pages, 5 figure

Gauge theory, topological strings, and S-duality

We offer a derivation of the duality between the topological U(1) gauge theory on a Calabi-Yau 3-fold and the topological A-model on the same manifold. This duality was conjectured recently by Iqbal, Nekrasov, Okounkov, and Vafa. We deduce it from the S-duality of the IIB superstring. We also argue that the mirror version of this duality relates the topological B-model on a Calabi-Yau 3-fold and a topological sector of the Type IIA Little String Theory on the same manifold.Comment: 9 pages, latex. v2: a footnote has been added. The footnote corrects an inaccuracy in the original argument; the results are unchanged. v3: exposition improve