RRR of Copper Coating and Low Temperature Electrical Resistivity of Material for TTF Couplers

In the framework of the R&D program on the TTF III main RF coupler, IPN Orsay developed in close collaboration with LAL institute, a dedicated facility for the electrical characterization of different materials at low temperature. This apparatus was used for measuring the electrical resistivity versus temperature (4.2 K- 300K) of various samples produced in the industry. These tests were performed in order to compare the RRR of the samples, qualify and find the optimum parameters for the coating process. Seven flat samples were tested in a saturated liquid helium bath under ~1013 mbar pressure: measurements were performed on bare 316L samples, nickel coated 316L samples, and copper coated 316L samples with a nickel under layer. We investigated, in particular, the effect of vacuum annealing at 400°C on the RRR of the copper coating. Our experimental data are compared to previous measurements reported by other groups, and theoretical results (e.g. Gruneisen-Bloch equation) and a good agreement was found. Finally, the tested samples fulfil the TTF III coupler design parameters requirements in terms of heat loads to the refrigerator at 2 K, 4 K and 70 K

Development of a TE011 Cavity for Thin-Films Study

Bulk niobium cavities have almost reached their maximum performances. Maximum accelerating gradient field is above 35-40 MV/m for a multi-cells cavity at 1.8 Kelvin and it achieves 25-30 MV/m with high reliability. The question of increasing the accelerating gradient in a significant way is running regarding the huge amount of units required for new projects (16000 units for ILC). A promising solution is to use thin films of new materials deposited on copper or niobium. In order to investigate the behaviour of these materials for the accelerating cavities, we have developed a dedicated setup based on thermometric method and a TE011 cavity. We present here the design study of the setup and the expected sensitivity of the method for the surface measurement of materials properties under RF fields

Electromechanical characterization of piezoelectric actuators subjected to a variable preloading force at cryogenic temperature

A dedicated apparatus was designed and constructed for studying the electromechanical behavior of prototype piezoelectric actuators subjected to a variable preloading force at cryogenic temperatures. This device was successfully used for testing a piezoelectric actuator of PICMA type from PI™, for T in the range 2 K-300 K. The dielectric properties as well as dynamic properties were measured including the actuator characteristics when used as force sensor. The corresponding data are reported and discussed

New State Observer Based On Takai-Sugeno Fuzzy Controller of Induction Motor

International audienceThis paper presents a nonlinear observer-based on Takagi-Sugeno (T-S)fuzzy controller design approach for induction motor (IM). The peculiarity of this paper is the synthesis of a mono-Luenberger observer for highly coupled system. The TS fuzzy model is firstly used to approximate the nonlinear IM systems. Next, based on the differential mean value theorem combined to the sector nonlinearity transformation , a nonlinear fuzzy observer is designed to estimate the system states in order to implement the fuzzy controller. Then, the parallel distributed compensator (PDC) scheme is used to design the fuzzy controller for the overall system. Fuzzy Controller and observer gains are obtained by solving a set of Linear Matrix Inequality (LMI).Finally, illustrative simulation results represented to validate the performance of the proposed approach

Effect of organic extracts of Bunium incrassatum on the hematological, ovarian and uterine parameters of mature female rabbit

This work aims to evaluate the effect of the organic extracts of Bunium incrassatum roots on some hematological parameters and histological changes of the genital tract. The study was achieved on mature rabbits of the local breed for 15 days. The animals were divided into five groups, which have daily administered 0, 25, 50, 100 and 200 mg/kg/day doses, respectively. The group with dose 0 was taken as a control. After treatment, the rabbits were sacrificed. The rabbit blood was collected in heparin tubes and their ovaries and uterus were removed, fixed in 10 % formalin; and stained with hematoxylin-eosin. The treatment induces a significant decrease in the level of Triglyceride, Cholesterol and a significant increase in the number of growing follicles accompanied by a decrease in atretic follicles, compared to the control group. The study shows that the organic extract of B. Incrassatum has estrogenic effects.Keywords: Bunium incrassatum, Organic extract, Rabbits, Ovaries, Follicles, Liver, Uteru