Experimental study of the recombination of a drifting low temperature plasma in the divertor simulator Mistral-B

In a new divertor simulator, an ultra-cold (Te<1 eV) high density recombining magnetized laboratory plasma is studied using probes, spectroscopic measurements, and ultra-fast imaging of spontaneous emission. The Mistral-B device consists in a linear high density magnetized plasma column. The ionizing electrons originate from a large cathode array located in the fringing field of the solenoid. The ionizing electrons are focused in a 3 cm diameter hole at the entrance of the solenoid. The typical plasma density on the axis is close to 2.10^18 m-3. The collector is segmented into two plates and a transverse electric field is applied through a potential difference between the plates. The Lorentz force induces the ejection of a very-low temperature plasma jet in the limiter shadow. The characteristic convection time and decay lengths have been obtained with an ultra-fast camera. The study of the atomic physics of the recombining plasma allows to understand the measured decay time and to explain the emission spectra.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Verification of Modular Systems with Unknown Components Combining Testing and Inference

26 pagesVerification of a modular system composed of communicating components is a difficult problem, especially when the formal specifications, i.e., models of the components are not available. Conventional testing techniques are not efficient in detecting erroneous interactions of components because interleavings of internal events are difficult to reproduce in a modular system. The problem of detecting intermittent errors and other compositional problems in the absence of components' models is addressed in this paper. A method to infer a controllable approximation of communicating components through testing is elaborated. The inferred finite state models of components are used to detect compositional problems in the system through reachability analysis. To confirm a flaw in a particular component, a witness trace is used to construct a test applied to the component in isolation. The models are refined at each analysis step thus making the approach iterative

Dielectric boundary effects on the interaction between planar charged surfaces with counterions only

Using Monte Carlo simulations in conjunction with periodic Green’s function methods, we study the interaction between planar charged surfaces with point-like counterions only in the presence of dielectric boundaries. Based on the calculated pressure profiles, we derive phase diagrams featuring correlation-induced negative pressure and thus attraction between the plates for large coupling parameters, i.e., low temperature or high surface charge and high ion valency. The counterion density profiles for low-dielectric and high-dielectric (metallic) surfaces are very different from the idealized case of a homogeneous dielectric constant. By contrast, the phase diagrams including the critical point and the two-phase coexistence region are rather insensitive to the presence of dielectric boundary effects. The single-image approximation that has been used in simulations before is by comparison with the exact formalism shown to be very accurate for low-dielectric surfaces but not for metallic surfaces

Dielectric boundary effects on the interaction between planar charged surfaces with counterions only

Using Monte Carlo simulations in conjunction with periodic Green’s function methods, we study the interaction between planar charged surfaces with point-like counterions only in the presence of dielectric boundaries. Based on the calculated pressure profiles, we derive phase diagrams featuring correlation-induced negative pressure and thus attraction between the plates for large coupling parameters, i.e., low temperature or high surface charge and high ion valency. The counterion density profiles for low-dielectric and high-dielectric (metallic) surfaces are very different from the idealized case of a homogeneous dielectric constant. By contrast, the phase diagrams including the critical point and the two-phase coexistence region are rather insensitive to the presence of dielectric boundary effects. The single-image approximation that has been used in simulations before is by comparison with the exact formalism shown to be very accurate for low-dielectric surfaces but not for metallic surfaces

Quantum absorption refrigerator with trapped ions

Thermodynamics is one of the oldest and well-established branches of physics that sets boundaries to what can possibly be achieved in macroscopic systems. While it started as a purely classical theory, it was realized in the early days of quantum mechanics that large quantum devices, such as masers or lasers, can be treated with the thermodynamic formalism. Remarkable progress has been made recently in the miniaturization of heat engines all the way to the single Brownian particle as well as to a single atom. However, despite several theoretical proposals, the implementation of heat machines in the fully quantum regime remains a challenge. Here, we report an experimental realization of a quantum absorption refrigerator in a system of three trapped ions, with three of its normal modes of motion coupled by a trilinear Hamiltonian such that heat transfer between two modes refrigerates the third. We investigate the dynamics and steady-state properties of the refrigerator and compare its cooling capability when only thermal states are involved to the case when squeezing is employed as a quantum resource. We also study the performance of such a refrigerator in the single shot regime, and demonstrate cooling below both the steady-state energy and the benchmark predicted by the classical thermodynamics treatment.Comment: 11 pages, 7 figures, 2 table

Focal High Intensity Focused Ultrasound for Prostate Cancer

Chapter Bookinfo:eu-repo/semantics/nonPublishe

Influence of Temperature and Storage Systems on Post-Harvest Losses of Maize Varieties Cultivated at Alibori in Northern Benin

Majority of post-harvest losses of several maize varieties observed in various storage systems in northern Benin are mainly caused by storage insects due to changes in climatic parameters. The objective of this study is to evaluate the levels of insect pest infestation of three maize varieties stored in storage systems at different temperature. In 18 villages at Alibori, maize farmers were surveyed through a participatory research approach and their storage structures were also visited. The temperature of all storage structures were noted. Weight loss of samples, numbers of Prostephanus truncates, Sitophilus zeamais and perforated grains were evaluated. In total, three maize varieties and three different groups of storage systems were identified during field observations. All the three maize varieties stored in the first storage systems group built with plants were less infested and had acceptable nutritional quality than the maize grains stored in the second group built in banco and third group built with tarpaulin. In these storage systems, the yellow maize variety was the most attacked, followed by the white maize variety and finally the mixed color of yellow and white maize variety the less attacked. Effective post-harvest management of stored products requires clear monitoring criteria of climatic parameters and effective implementation of abiotic and biotic factors