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

Evaluation of innovative microreactor for examination of alkoxide pitting corrosion and data generation for numerical transient model

In fuel‐bearing components, particularly in automotive applications operating at elevated temperatures, the durability of light metals is significantly influenced by their susceptibility to alkoxide corrosion. Alkoxide corrosion is characterized by its spontaneous nature and exceptionally rapid degradation of materials once initiated. This study presents an innovative high‐pressure and high‐temperature micro‐reactor, which enables precise measurements with superior sensitivity for determining the exact initiation times and reaction rates of pitting corrosion. Exemplified tests of surface roughness and water content effect on pitting initiation times were conducted and data was generated for a numerical phase field model to demonstrate the reactor capabilities. Experimental findings suggest that impurities present on both the material surface and in the fuel exhibit a significant influence on corrosivity, thereby affecting the reliability of the components. Moreover, the experimental data points have been utilized to extract the corrosion kinetics and calibrate the numerical model. The initial findings successfully demonstrate the ability to replicate corrosion kinetics and accurately represent pit morphologies and estimate reaction‐related parameters in a predictive manner

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 %

Influence of carbon diffusion on microstructure and wear behaviour of duplex stainless steel surface layers on lamellar grey cast iron

Surface welding with duplex stainless steel was performed to enhance the wear and corrosion properties of grey cast iron, which is used as material for applications as pump components in maritime and chemical environments. The method used for surface welding and the corresponding process parameters determine the chemical composition and microstructure, which both determine the corrosion and wear properties of the surface layer. High heat input leads to high chemical dilution and thus, reduced corrosion resistance. Slow cooling rates, which are recommended for welding of grey cast iron components, facilitate the formation of carbides in the fusion zone of the chromium‐rich duplex stainless steel surface layer. On the one hand, carbides lead to increased hardness and thus, improved wear resistance of the surface layers. On the other hand, carbides and high chemical dilution rates reduce the corrosion resistance and therefore should be avoided. Under high cooling rates, the risk of cracking in the heat affected zone of the grey cast iron increases due to martensitic phase transformations. The paper describes the correlation of process parameters, microstructure and chemical composition with a focus on carbon diffusion and carbide formation, ever considering the effect on the wear behaviour in an oscillation tribometer and under erosion‐corrosion conditions

Corrosion Resistance and Microstructure of Welded Duplex Stainless Steel Surface Layers on Gray Cast Iron

The degradation of pump components by corrosion and complex, simultaneous damage mechanisms, e.g., erosion–corrosion and cavitation–corrosion leads to high costs through replacement and maintenance of parts. To increase the lifetime of cost-efficient components with superior casting properties, surface welding of duplex stainless steel on gray cast iron parts was performed using inert shielding gas metal arc surface welding (GMA-SW) and plasma transferred arc surface welding (PTA-SW). The thermal conductivity of the used shielding gas and the preheating temperature influenced the dilution of the surface layers, which had a major impact on the corrosion resistance and the microstructure. Lower cooling rates enhanced diffusion and lead to precipitation of carbides. High heat input and prolonged cooling times during surface welding resulted in high dilution and a carbide network. The corrosion resistance in artificial seawater of those surface layers was substantially reduced compared to surface layers with lower heat input and higher cooling rates. The corrosion of the surface layers in the potentiodynamic polarization test was driven by selective corrosion of the phase boundary between Cr–carbides and Cr–depleted austenite. Passive behavior was observed for surface layers with low dilution, which had homogeneous chromium distribution and no carbide networks. In conclusion, the corrosion behavior of gray cast iron was improved by surface welding with duplex stainless steel. The corrosion resistance of the surface layers produced with PTA-SW with no preheating exceeded that of the surface layers produced with GMA-SW and came close to those of a commercially available duplex stainless steel used as reference material

Female heterozygotes for the hypomorphic R40H mutation can have ornithine transcarbamylase deficiency and present in early adolescence: a case report and review of the literature

<p>Abstract</p> <p>Introduction</p> <p>Ornithine transcarbamylase deficiency is the most common hereditary urea cycle defect. It is inherited in an X-linked manner and classically presents in neonates with encephalopathy and hyperammonemia in males. Females and males with hypomorphic mutations present later, sometimes in adulthood, with episodes that are frequently fatal.</p> <p>Case presentation</p> <p>A 13-year-old Caucasian girl presented with progressive encephalopathy, hyperammonemic coma and lactic acidosis. She had a history of intermittent regular episodes of nausea and vomiting from seven years of age, previously diagnosed as abdominal migraines. At presentation she was hyperammonemic (ammonia 477 μmol/L) with no other biochemical indicators of hepatic dysfunction or damage and had grossly elevated urinary orotate (orotate/creatinine ratio 1.866 μmol/mmol creatinine, reference range <500 μmol/mmol creatinine) highly suggestive of ornithine transcarbamylase deficiency. She was treated with intravenous sodium benzoate and arginine and made a rapid full recovery. She was discharged on a protein-restricted diet. She has not required ongoing treatment with arginine, and baseline ammonia and serum amino acid concentrations are within normal ranges. She has had one further episode of hyperammonemia associated with intercurrent infection after one year of follow up. An R40H (c.119G>A) mutation was identified in the ornithine transcarbamylase gene (<it>OTC</it>) in our patient confirming the first symptomatic female shown heterozygous for the R40H mutation. A review of the literature and correspondence with authors of patients with the R40H mutation identified one other symptomatic female patient who died of hyperammonemic coma in her late teens.</p> <p>Conclusions</p> <p>This report expands the clinical spectrum of presentation of ornithine transcarbamylase deficiency to female heterozygotes for the hypomorphic R40H <it>OTC </it>mutation. Although this mutation is usually associated with a mild phenotype, females with this mutation can present with acute decompensation, which can be fatal. Ornithine transcarbamylase deficiency should be considered in the differential diagnosis of unexplained acute confusion, even without a suggestive family history.</p

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

The Parkinson disease pain classification system: Results from an international mechanism-based classification approach

Pain is a common nonmotor symptom in patients with Parkinson disease (PD) but the correct diagnosis of the respective cause remains difficult because suitable tools are lacking, so far. We developed a framework to differentiate PD- from non-PD-related pain and classify PD-related pain into 3 groups based on validated mechanistic pain descriptors (nociceptive, neuropathic, or nociplastic), which encompass all the previously described PD pain types. Severity of PD-related pain syndromes was scored by ratings of intensity, frequency, and interference with daily living activities. The PD-Pain Classification System (PD-PCS) was compared with classic pain measures (ie, brief pain inventory and McGill pain questionnaire [MPQ], PDQ-8 quality of life score, MDS-UPDRS scores, and nonmotor symptoms). 159 nondemented PD patients (disease duration 10.2 6 7.6 years) and 37 healthy controls were recruited in 4 centers. PDrelated pain was present in 122 patients (77%), with 24 (15%) suffering one or more syndromes at the same time. PD-related nociceptive, neuropathic, or nociplastic pain was diagnosed in 87 (55%), 25 (16%), or 35 (22%), respectively. Pain unrelated to PD was present in 35 (22%) patients. Overall, PD-PCS severity score significantly correlated with pain’s Brief Pain Inventory and MPQ ratings, presence of dyskinesia and motor fluctuations, PDQ-8 scores, depression, and anxiety measures. Moderate intrarater and interrater reliability was observed. The PD-PCS is a valid and reliable tool for differentiating PD-related pain from PD-unrelated pain. It detects and scores mechanistic pain subtypes in a pragmatic and treatment-oriented approach, unifying previous classifications of PD-pain.Fil: Mylius, Veit. Universitat Phillips; Alemania. Center for Neurorehabilitation; Suiza. Kantonsspital St; SuizaFil: Perez Lloret, Santiago. Universidad Abierta Interamericana. Secretaría de Investigación. Centro de Altos Estudios En Ciencias Humanas y de la Salud - Sede Buenos Aires.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; ArgentinaFil: Cury, Rubens G.. Universidade de Sao Paulo; BrasilFil: Teixeira, Manoel J.. Universidade de Sao Paulo; BrasilFil: Barbosa, Victor R.. Universidade de Sao Paulo; BrasilFil: Barbosa, Egberto R.. Universidade de Sao Paulo; BrasilFil: Moreira, Larissa I.. Universidade de Sao Paulo; BrasilFil: Listik, Clarice. Universidade de Sao Paulo; BrasilFil: Fernandes, Ana M.. Universidade de Sao Paulo; BrasilFil: de Lacerda Veiga, Diogo. Universidade de Sao Paulo; BrasilFil: Barbour, Julio. Universidade de Sao Paulo; BrasilFil: Hollenstein, Nathalie. Universidade de Sao Paulo; BrasilFil: Oechsner, Matthias. Center for Neurological Rehabilitation; SuizaFil: Walch, Julia. Kantonsspital St; SuizaFil: Brugger, Florian. Kantonsspital St; SuizaFil: Hägele Link, Stefan. Kantonsspital St; SuizaFil: Beer, Serafin. Center for Neurorehabilitation; SuizaFil: Rizos, Alexandra. King's College Hospital; Reino UnidoFil: Chaudhuri, Kallol Ray. The Maurice Wohl Clinical Neuroscience Institute; Reino Unido. King's College Hospital; Reino UnidoFil: Bouhassira, Didier. Université Versailles-Saint-Quentin; Francia. Hôpital Ambroise Paré; FranciaFil: Lefaucheur, Jean Pascal. Université Paris-Est-Créteil; FranciaFil: Timmermann, Lars. Universitat Phillips; AlemaniaFil: Gonzenbach, Roman. Center for Neurorehabilitation; SuizaFil: Kägi, Georg. Kantonsspital St; SuizaFil: Möller, Jens Carsten. Universitat Phillips; Alemania. Center for Neurological Rehabilitation; SuizaFil: Ciampi de Andrade, Daniel. Universidade de Sao Paulo; Brasi

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