The lightest neutralino in the MNSSM

We examine the allowed mass range of the lightest neutralino within the Minimal Non--minimal Supersymmetric Standard Model. Being absolutely stable if R-parity is conserved this lightest neutralino is a candidate for the dark matter of the universe. We establish the theoretical upper bound on the lightest neutralino mass and obtain an approximate solution for this mass.Comment: Submitted for the SUSY07 proceedings, 4 pages, LaTeX, 3 eps figures, some minor changes to the tex

Pseudo-elastic Flexure-Hinges in Robots for Micro Assembly

The increasing tendency of products towards miniaturization makes the substitution of conventional hinges to flexure hinges necessary, since they can be manufactured almost arbitrarily small. On account of their multiple advantages like no backlash, no slip-stick-effects and no friction, their application is especially reasonable in high-precision robots for micro assembly. Particular pseudo-elastic shape memory alloys offer themselves as material for flexure hinges. Since flexible joints gain their mobility exclusively via the elastic deformation of matter, the attainable angle of rotation is strongly limited when using conventional metallic materials with approximately 0.4% maximal elastic strain. Using pseudo-elastic materials, with up to 15% elastic strain, this serious disadvantage of flexure hinges can be avoided. A further problem of flexible joints is their kinematic behavior since they do not behave exactly like conventional rotational joints. In order to examine the kinematics of the hinges an experimental set-up was developed whereby good compliance with theoretical computed values could be achieved. A three (+1) degree of freedom parallel robot with integrated flexure hinges is investigated showing its kinematic deviations to its rigid body model. The data of the kinematic model of the flexible joint can then be implemented into the control of this compliant mechanism in order to gain not only a higher repeatability but also a good absolute accuracy over the entire working space

Effects of Implementing Efficiency Techniques in the Plastics Industry in Germany and Western Australia – A Comparative Modelling Assessment

Plastics manufacturing is an important industry in many countries. Energy consumption in particular can be very high. Energy efficiency is an increasing area of management interest given pricing pressures on manufacturing companies around the world. In some cases simulation can help to predict the results of implementing different technologies to improve energy efficiencies. This paper focuses on the results of a simulation model which deals with the substitution of electric power with natural gas and the cooling of moulds by absorption chillers in plastics production. The methodology reviewed can result in significant reductions in energy demand and is also valuable when energy requirements for heating purposes are relevant. Germany and Western Australia both represent different climatic regions, but the modelling assessment on production facilities in both countries highlights the benefits of taking a whole systems approach to energy saving and energy efficiency in plastic production

Compliant parallel robot with 6 DOF

In this paper a patented parallel structure1 will be presented in which conventional bearings are replaced by flexure hinges made of pseudo-elastic shape memory alloy. The robot has six degrees of freedom and was developed for micro assembly tasks. Laboratory tests made with the robot using conventional bearings have shown that the repeatability was only a couple of 1/100 mm instead of the theoretical resolution of the platform of < 1 pm. Especially the slip-stick effects of the bearings decreased the positional accuracy. Because flexure hinges gam their mobility only by a deformation of matter, no backlash, friction and slip-stick-effects exist in flexure hinges. For this reason the repeatability of robots can be increased by using flexure hinges. Joints with different degrees of freedom had to be replaced in the structure. This has been done by a combination of flexure hinges with one rotational degree of freedom. FEM simulations for different designs of the hinges have been made to calculate the possible maximal angular deflections. The assumed maximal deflection of 20° of the hinges restricts the workspace of the robot to 28x28 mm with no additional rotation of the working platform. The deviations between the kinematic behavior of the compliant parallel mechanism and its rigid body model can be simulated with the FEM

Application of riblets on turbine blade endwall secondary flow control

© 2015 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Within the past 10 years, significant improvements have been achieved in the laser manufacturing process. It is feasible now to design various small-scale surface features (such as dimples, riblets, grooves, etc.) in gas turbine applications with the current manufacturing readiness level of laser surface texturing techniques. In this paper, the potential of adding riblets on a turbine endwall has been investigated through combined computational fluid dynamics and experimental studies in a low-speed linear cascade environment. Detailed comparisons of the flow structures have been made for cases with and without riblets on the endwall. The numerical results show that endwall riblets can effectively reduce the strength of the pressure side leg of the horseshoe vortex, lower the cross-passage pressure gradient, and alleviate the lift up of the passage vortex. Oil filmflowvisualization and exit aerodynamic loss survey in experiments support the computational fluid dynamics observations: The passage vortex loss core moves closer to the endwall with the addition of riblets. The present study consistently demonstrates that the addition of riblets can be an effective approach to reduce the endwall secondary flow. Further research questions are raised for the applicability of the riblets concept in actual engine conditions and options for design optimization

Lightest Neutralino Mass in the MNSSM

We argue that the allowed range of the mass of the lightest neutralino in the MNSSM is limited. We establish the theoretical upper bound on the lightest neutralino mass and obtain an approximate solution for this mass.Comment: Poster presented at ICHEP08, Philadelphia, USA, July 2008. 3 pages, LaTeX, 2 eps figure

Physics at International Linear Collider (ILC)

International Linear Collider (ILC) is an electron-positron collider with the initial center-of-mass energy of 500 GeV which is upgradable to about 1 TeV later on. Its goal is to study the physics at TeV scale with unprecedented high sensitivities. The main topics include precision measurements of the Higgs particle properties, studies of supersymmtric particles and the underlying theoretical structure if supersymmetry turns out to be realized in nature, probing alternative possibilities for the origin of mass, and the cosmological connections thereof. In many channels, Higgs and leptonic sector in particular, ILC is substantially more sensitive than LHC, and is complementary to LHC overall. In this short article, we will have a quick look at the capabilities of ILC.Comment: To appear in JPSJ Vol76 No1

H^\pm W^\mp production in the MSSM at the LHC

We investigate the viability of observing charged Higgs bosons (H^\pm) produced in association with W bosons at the CERN Large Hadron Collider, using the leptonic decay H^+ -> tau^+ nu_tau and hadronic W decay, within the Minimal Supersymmetric Standard Model. Performing a parton level study we show how the irreducible Standard Model background from W + 2 jets can be controlled by applying appropriate cuts. In the standard m_h^max scenario we find a viable signal for large tan beta and intermediate H^\pm masses (~ m_t).Comment: 3 pages, LaTeX, 4 eps figures, uses jpconf.cls, talk given by S. Hesselbach at the 2007 Europhysics Conference on High Energy Physics, Manchester, England, 19-25 July 200

BALANCEO DE CARGA EN REDES MPLS

RESUMEN.Uno de los aspectos más importantes e interesantes en investigación en las redes de hoy, es el relacionado con la Ingeniería de Tráfico (TE: Traffic Engineering), ya que posibilita la optimización en el uso de los recursos y mejora la operabilidad de la red. De otra parte, la Conmutación de Etiquetas Multiprotocolo (MPLS: MultiProtocol Label Switching) posee características que le permiten realizar funciones de Ingeniería de Tráfico contribuyendo con la mejora de la red en el backbone. Un aspecto considerado por la TE es el Balanceo de carga (Load Balancing), mecanismo que contribuye a la reducción de la congestión en las redes y a mejorar el uso de los recursos disponibles en la red. El Balanceo de carga utiliza los caminos paralelos existentes entre el nodo de ingreso y el nodo de egreso de la red; en una red MPLS dichos caminos corresponden a los LSP´s (Label Switched Path) establecidos entre el LSR-I (Label Switching Router – Ingrees) y el LSR-E (Label Switching Router – Egrees). Este artículo ofrece los aspectos relevantes sobre el problema de balanceo de carga y presenta las aproximaciones existentes para su solución.PALABRAS CLAVESMPLSBalanceo de carg