331 research outputs found
BORAY: A ray tracing code for various magnetized plasma configurations
No full textRay tracing codes are useful to study the electromagnetic wave propagation and absorption in the geometrical optics approximation. In magnetized fusion plasma community, most ray tracing codes assume the plasma density and temperature be functions of the magnetic flux and study waves only inside the last closed flux surface, which are sufficient for the present day tokamak. However, they are difficult to be used for configurations with open magnetic field line plasmas, such as mirror machine and field-reversed-configuration (FRC). We develop a ray tracing code in cylindrical coordinates (r,φ,z) to support arbitrary axisymmetric configurations with both closed and open field lines plasmas. For wave propagation, the cold plasma dispersion relation is usually sufficient, and we require the magnetic field B(r,z) and species densities ns0(r,z) profiles as input. For wave absorption, we require a further temperature Ts0(r,z) profile to solve a hot kinetic plasma dispersion relation. In difference to other ray tracing codes which calculate the imaginary part of wave vector k⊥,i for wave absorption, we calculate the imaginary part of wave frequency ωi, which is shown to be equivalent with the former technique under weak damping approximation. The code can use either numerical or analytical equilibrium. Examples and benchmarks with electron cyclotron wave, lower hybrid wave and ion cyclotron wave for tokamak, spherical tokamak (ST), FRC and mirror machine are shown. Program summary: Program Title: BORAY CPC Library link to program files: https://doi.org/10.17632/tnkrjdbcz8.1 Code Ocean capsule: https://codeocean.com/capsule/6205646 Licensing provisions: BSD 3-clause Programming language: Matlab Nature of problem: Solve the plasmas electromagnetic wave propagation and absorption in the geometrical optics approximation for magnetized plasmas based on ray tracing of plasma dispersion relation. In axisymmetric (r,z) coordinates, the code can be used for both closed and open field lines plasmas of various configurations such as tokamak, spherical tokamak, FRC and mirror machine. Solution method: Runge-Kutta time integral to solve ray tracing equations for wave propagation, and integral the imaginary part of the wave frequency in hot kinetic dispersion relation for wave absorption. Additional comments including restrictions and unusual features: Kinetic relativistic effects and collisional damping are not included in the present version yet. Only axisymmetric two-dimensional (2D) profiles are support in present version
Curious Behavior of Fe3+-As3+ Chemical Interactions and Nucleation of Clusters in Aqueous Medium
No full textThis study reveals the existence of FeAs clusters (primarilyFe(4)As(4), having a tooeleite-like local structure)in a nearly groundwater-like situation, i.e., far from the acid minedrainage condition, consequently entrapping As3+ from suchsolutions within tooeleite-like cages.The simultaneous presence of Fe3+ and As3+ ions in groundwater (higher ppb or lowerppm level concentrationsat circumneutral pH) as well as in acid mine drainages (AMDs)/industrialwastewater (up to few thousand ppm concentration at strongly acidicpH) are quite common. Therefore, understanding the chemical interactionsprevalent between Fe3+ and As3+ ions in aqueousmedium leading to nucleation of ionic clusters/solids, followed byaggregation and growth, is of great environmental significance. Inthe present work, we attempt to probe the nucleation process of Fe3+-As3+ clusters in solutions of various concentrationsand pHs (from AMD to groundwater-like) using a combination of experimentaland theoretical techniques. Interestingly, our study reveals nucleationof primary FeAs clusters in nearly all of them independent of concentrationor pH. Theoretical studies employed density functional theory (DFT)to predict the primary clusters as stable Fe4As4 units. The surprising resemblance of these clusters with known Fe3+-As3+ minerals at the local level was observedexperimentally, which provides an important clue about solid-phasegrowth from a range of Fe3+-As3+ solutions.Our experimental findings are further supported by a stepwise reactionmechanism established from detailed DFT studies
Assessing Distribution Potential of Hevea Brasiliensis Using Ecological Niche Modelling Approach
No full textComputation of nonlinear structures: extremely large elements for frames, plates and shells
No full textDisparities in Health Care Resource Utilization and Expenditures in Prostate Cancer Patients in the United States
No full textVariation of Local Flexibility Coefficients of Functionally Graded Cracked Shaft
No full textAbstractThe present paper deals with the analytical determination of local flexibility coefficients (LFCs) for a functionally graded (FG) cracked shaft. Finite element (FE) analysis has been performed using two nodded beam element having six degrees of freedom (DOF) at each node and Timoshenko beam theory (TBT) has been used. Material properties are assumed to be graded in radial direction following linear, power law and exponential law gradation respectively. In the present analysis, the mixture of Aluminum Oxide (Al2O3) and Stainless Steel (SUS304) is considered as FG material where metal content is considered decreasing towards the outer diameter of shaft. The LFCs of a cracked shaft is derived using Castigliano's theorem and Paris's equations in conjunction with the expression for stress intensity factors. A complete code has been developed using MATLAB program and validated with the existing results available in literatures. The LFCs are calculated for different crack depths and for different crack closer lines for a cracked shaft and the effect of crack depth and crack closer line position on the LFCs has been studied. Numerical results reveal that for a given crack configuration, LFCs values are maximum for metallic, minimum for ceramic shaft and the LFCs for FG shaft in between, and also the LFCs values increase with the increasing power law gradient indices
Regioselective ortho Amination of Coordinated 2-(Arylazo)pyridine. Isolation of Monoradical Palladium Complexes of a New Series of Azo-Aromatic Pincer Ligands
No full textIn an unusual reaction of [Pd(L-1)Cl-2] (L-1 = 2-(arylazo)pyridine) with amines, a new series of palladium complexes [Pd(L2 center dot-)CI] (L-2 = 2-((2-amino)arylazo)pyridine) (1a-1h) were isolated. The complexes were formed via N-H and N-C bond cleavage reactions of 1 degrees/2 degrees and 30 amines, respectively, followed by regioselective aromatic ortho-C-N bond formation reaction and are associated with ortho-C-H/ortho-C-Cl bond activation. A large variety of amines including both aromatic and aliphatic were found to be effective in producing air-stable complexes. Identity of the resultant complexes was confirmed by their X-ray structure determination. Efforts were also made to understand the mechanism of the reaction. A series of experiments were performed, which point toward initial ligand reduction followed by intraligand electron transfer. Examination of the structural parameters of these complexes (1) indicates that the in situ generated ligand coordinated to the Pd-II center serves as the backbone of these air-stable monoradical complexes. Molecular and electronic structures of the isolated complexes were further scrutinized by various spectroscopic techniques including cyclic voltammetry, variable temperature magnetic susceptibility measurements, electron paramagnetic resonance, and UV-vis spectroscopy. Finally the electronic structure was confirmed by density functional theory calculations. The isolated monoradical complexes adopt an unusual pi-stacked array, which leads to a relatively strong antiferromagnetic interaction (J = 40 cm(-1) for the representative complex 1c)
Guidewire crossing techniques in coronary chronic total occlusion intervention: A to Z
No full textAbstractPercutaneous coronary intervention (PCI) of chronic total occlusion (CTO) poses a management dilemma for the interventional cardiologist. Effective wiring technique is the key to success of PCI in CTO, which requires more patience and skill of the operator. The author herein intends to explore in detail the different wiring strategies such as antegrade approach, dissection and reentry, retrograde and hybrid approach. Hopefully, this review would enhance the understanding of this complex procedure and, consequently, promote safe and effective PCI
SALICYLAMIDOXIME AS AN ANALYTICAL REAGENT. PART II. GRAVIMETRIC ESTIMATION OF COPPER AND NICKEL AND THEIR SEPARATION FROM OTHER METALS
No full textThe use of salicylamidoxime as a reagent for the gravimetric estimation of copper and nickel by weighing the precipitates of composition M(C7H7O2N2)2, where M=Cu or Ni, after drying at 110o, is described. Copper can he effectively separated from mercuryII , lead, cadmium, zinc, manganeseII and cobaltII by precipitating the copper with an excess of the amidoxime at a PH of 4.0-4.5; while for the separation from ironIII, antimonyIII and bismuthIII, the precipitation should be carried out in presence of sufficient tartaric acid at PH of 4.0-4.5. Nickel can similarly be separated from zinc quantitatively by precipitation with the reagent at a controlled PH (7.0-7 5) in the presence of some ammonium chloride to prevent the precipitation of the latter element. Determinations of copper and nickel in mixed solutions have been carried out by precipitating copper in an acetate-buffer of PH near about 4; in the filtrates nickel was precipitated by adding more of the reagent and then ammonia to adjust the PH of the solution to 7.0-7.5
- …
