Coalition Stability with Heterogeneous Agents

We analyze coalition formation with heterogeneous agents based on an individual stability concept. Defining exchanging and refractory agents, we give existence and enlargement conditions for coalitions with heterogeneous agents. Using the concept of exchanging agents we give necessary conditions for internal stability and show that refraction is a sufficient condition for the failure of an enlargement of the coalition.Heterogeneity, Coalition, Exchanging, Refraction.

Time interval moderates the relationship between psyching-up and actual sprint performance

This study attempted to test whether the strongest effect of psyching-up (PU) strategy on actual sprint performance can be observed when the strategy is used immediately (or almost) before performance compared with when there is a delay between PU and performance. To do so, 16 male sprinters (age, 20.6 ± 1.3 years; body mass, 77.5 ± 7.1 kg; height, 180.8 ± 5.6 cm) were enrolled in a counterbalanced experimental design in which participants were randomly assigned to 10 sessions (2 [Experimental Condition: imagery vs. distraction] × 5 [Time Intervals: no interval, 1 minute, 2 minutes, 3 minutes, and 5 minutes]). Before performing the experimental tasks, participants rated: (a) the Hooper index, (b) their degree of self-confidence, and (c) after the completion of the experimental test; they rated their perceived effort. Findings showed that the imagery significantly improved sprint performance. Specifically, the imagery enhanced performance on the phase of acceleration (0-10 m) and on the overall sprint (0-30 m) when used immediately before performance and at 1- and 2-minute intervals but not for 3- and 5-minute intervals. These findings support the hypothesis that the potential effect of the PU strategy on performance vanishes over time. The pre-experimental task Hooper and self-efficacy indexes did not change across the 10 experimental sessions, reinforcing the view that the observed performance changes were directly caused by the experimental manipulation and not through any altered status of the athletes (self-efficacy, fatigue/recovery, and stress). The potential mechanisms underlying such a process and practical applications are discussed

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

Strain analysis at flat surfaces of loaded members using digital image correlation technique

This research examines the applicability of the planned Digital Image Correlation (DIC) system to measure the strains in tensile experiments. DIC is a low-cost optical technique, and is an appropriate measurement used to measure surface displacement, strain and stress map distribution without any contact with the tested surfaces. In the present research, the tensile test is conducted on two different flat samples, which are painted in a speckle pattern on the tested surface to use DIC features in stain measurements. To guarantee the efficiency of the planned DIC system, the DIC code has been built using MATLAB programming language. The obtained results from DIC technique is compared with the results from open-source software (Ncorr), the finite element analysis (ANSYS) as well as the exact and analytical solutions. The comparison results showed that there was A quite acceptable and agreement achieved between them. According to the exact solution, The percentage of accuracy of the obtained results for the Aluminum without hole plate was around (89-93) % whereas the accuracy with the NCORR was about 96 %. For the second copper plate with a central hole, the accuracy has been obtained to be (80.7-99) % with the analytical solution wherein its value has reached (81-97) % with Ncorr software

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

Radiation Hardness Tests Of Piezoelectric Actuators With Fast Neutrons At Liquid Helium Temperature

Piezoelectric actuators, which are integrated into the cold tuning system and used to compensate the small mechanical deformations of the cavity wall induced by Lorentz forces due to the high electromagnetic surface field, may be located in the radiation environment during particle accelerator operation. In order to provide for a reliable operation of the accelerator, the performance and life time of piezoelectric actuators (~24.000 units for ILC) should not show any significant degradation for long periods (i.e. machine life duration: ~20 years), even when subjected to intense radiation (i.e. gamma rays and fast neutrons). An experimental program, aimed at investigating the effect of fast neutrons radiation on the characteristics of piezoelectric actuators at liquid helium temperature (i.e. T~4.2 K), was proposed for the working package WP#8 devoted to tuners development in the frame of CARE project. A neutrons irradiation facility, already installed at the CERI cyclotron located at Orléans (France), was upgraded and adapted for actuators irradiations tests purpose. A deuterons beam (maximum energy and beam current: 25 MeV and 35µA) collides with a thin (thickness: 3 mm) beryllium target producing a high neutrons flux with low gamma dose (~20%): a neutrons fluence of more than 1014 n/cm2 is achieved in ~20 hours of exposure. A dedicated cryostat was developed at IPN Orsay and used previously for radiation hardness test of calibrated cryogenic thermometers and pressure transducers used in LHC superconducting magnets. This cryostat could be operated either with liquid helium or liquid argon. This irradiation facility was upgraded for allowing fast turn-over of experiments and a dedicated experimental set-up was designed, fabricated, installed at CERI and successfully operated for radiation hardness tests of several piezoelectric actuators at T~4.2 K. This new apparatus allows on-line automatic measurements of actuators characteristics and the cryogenic parameters. Further, the test-cell and actuators are equipped with high purity Ni foils for measuring the total neutrons dose by an activation method. In this report, the details of the irradiation test facility will be described then the experimental data will be analyzed and discussed