Energy spectrum of a 2D Dirac electron in the presence of a constant magnetic field

In this paper we obtain exact solutions of a 2D relativistic Dirac oscillator in the presence of a constant magnetic field. We compute the energy spectrum and discuss its dependence on the spin and magnetic field strength.Comment: 7 page

McLeod myopathy revisited: more neurogenic and less benign

The X-linked McLeod neuroacanthocytosis syndrome (MLS) has originally been denoted as ‘benign' McLeod myopathy. We assessed the clinical findings and the muscle pathology in the eponymous index patient, Hugh McLeod, and in nine additional MLS patients. Only one patient had manifested with neuromuscular symptoms. During a mean follow-up of 15 years, however, eight patients including the initial index patient showed elevated skeletal muscle creatine kinase levels ranging from 300 to 3000 U/L, and had developed muscle weakness and atrophy. Two patients had disabling leg weakness. Muscle histology was abnormal in all 10 patients. Clear but unspecific myopathic changes were found in only four patients. All patients, however, had neurogenic changes of variable degree. Post-mortem motor and sensory nerve examinations support the view that muscle atrophy and weakness are predominantly due to an axonal motor neuropathy rather than to a primary myopathy. Multisystem manifestations developed in eight patients at a mean age of 39 years. Three patients manifested with psychiatric features comprising schizophrenia-like psychosis and personality disorder, two presented with generalized seizures and one with chorea. During follow-up, seven patients developed chorea, six had psychiatric disorders, five had cognitive decline and three had generalized seizures. Five patients died because of MLS-related complications including sudden cardiac death, chronic heart failure and pneumonia between 55 and 69 years. In conclusion, our findings confirm that MLS is not a benign condition but rather a progressive multisystem disorder sharing many features with Huntington's diseas

Determination of the s‐phase formation coefficient of plasma nitrided austenitic steel

Plasma nitriding is an effective surface hardening treatment for austenitic stainless steels. During plasma nitriding, s‐phase formation takes place which is not only responsible for high hardness and wear resistance but also for good corrosion resistance. In order to estimate the thickness of the s‐phase for austenitic stainless steel in a plasma nitriding process, an empirical model is devised. A number of plasma nitriding processes of austenitic stainless steel (304 L) were carried out with varying treatment temperature from 360 °C to 450 °C and process duration ranging from 10 hours to 24 hours with constant pressure, voltage, pulse‐to‐pause‐ratio and gas mixture. A time‐temperature dependent s‐phase formation coefficient is determined by measuring the thickness of the s‐phase using a scanning electron microscope (SEM) and glow discharge optical emission spectroscopy (GDOES). The developed model is verified by three controlled experiments. This model fits the thickness of the s‐phase with an error of less than 6 %

Simulation of cylindrical electron cyclotron wave resonance argon discharges

International audienceA fluid model of a cylindrical electron cyclotron wave resonance (ECWR) Argon discharge is presented. The results for a 1 mTorr Argon discharge were checked against the analytical theory, simulation and experimental data. The basic plasma properties as power dissipation, magnetic field, electric potential, electron density and temperature were very well reproduced by using pre-defined boundary conditions for the magnetic potential. The results of this model were further used as inputs for the simulation of plasma expansion into a diffusion region, allowing thus fast and complete modeling of a typical ECWR plasma reactor

Friction reduction and zero wear for 52100 bearing steel by high‐dose implantation of carbon

Ion implantation of carbon in the AISI 52100 bearing steel yields a distinct reduction in friction and wear. This improvement is strongly dependent on the implanted fluence. The coefficient of friction decreases from 0.6 to 0.2 for doses >1×1018 cm-2 (energy 100 keV) and a wear reduction to nearly ‘‘zero wear’’ was obtainable even under severe wear conditions. The counterpart (unimplanted AISI 52100 steel ball) shows a similar behavior, which demonstrates that the tribological system is totally changed. Mössbauer spectroscopy and x-ray diffraction revealed that hexagonal ¿-carbide is formed on implantation. On the other hand, Rutherford backscattering spectrometry shows that for high doses a large fraction of the implanted carbon is not contained in this carbide

Towards a standardization of biomethane potential tests

8 PáginasProduction of biogas from different organic materials is a most interesting source of renewable energy. The biomethane potential (BMP) of these materials has to be determined to get insight in design parameters for anaerobic digesters. A workshop was held in June 2015 in Leysin Switzerland to agree on common solutions to the conundrum of inconsistent BMP test results. A discussion covers actions and criteria that are considered compulsory ito accept and validate a BMP test result; and recommendations concerning the inoculum substrate test setup and data analysis and reporting ito obtain test results that can be validated and reproduced.The workshop in Leysin, Switzerland, has been financed by the Swiss Federal Office for Energy, and co-sponsored by Bioprocess Control Sweden AB, Lund, Sweden. The authors thank Alexandra Maria Murray for editing the English