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Boronizing was performed by using a solid medium of Ekabor powders at 1073, 1148 and 1223K for 2, 4 and 8h. After boronizing, the major dominant phase was found to be Fe 2 B and the minors were CrB and Ni 2 B. Boride coating resulted in smooth and dense feature confirmed by optical and SEM. The thickness of boride layer varied from 7 to 87μm depending on the process time and temperature...
In order to develop wear resistance diamond/molybdenum (Mo) hybrid coating process can be conducted in open air. Diamond deposition on the molybdenum with thermal stress buffer layer coated mild steel substrate by the combustion flame chemical vapor deposition (CFCVD) was carried out. As the thermal stress buffer layer, atmospheric plasma sprayed Mo/Fe mixture coating was deposited between Mo top...
Plasma arc heating technology has been applied for volume reduction through melting of bottom and fly ash, and for producing slag. Recently, a twin torch plasma arc, which has two torches at the cathode and anode, has been anticipated for application to disposal of medical waste because it can treat a wide area and can treat non-conductive materials. For this study, a numerical simulation model of...
The diamond-like carbon (DLC) film was prepared on various metal substrates with a plasma-based ion implantation and deposition using superimposed RF and negative high-voltage pulses. The adhesion strength of DLC film was enhanced above the epoxy resin strength by implantation of carbon ions or mixed ions of carbon and silicon to the substrate surface before DLC deposition. In order to clarify the...
An experimental plasma-chemical reactor equipped with a novel hybrid gas–water stabilized torch is available at IPP Prague for the innovative and environmentally friendly plasma treatment of waste streams with a view to their sustainable energetic and chemical valorization and to a reduction of the emission of greenhouse gases. Gasification/pyrolysis of biomass was experimentally studied using crushed...
A computer code of variational principle for the plasma potential energy was written and used to analyze magnetohydrodynamic instability in D-shaped tokamak. Paths of steepest descent are defined by solving an initial value problem for a system of partial differential equations which are expressed in terms of artificial time parameter. Pressure of plasma, flux surfaces, plasma energy and safety factor...
The effect of stress on abrasive and erosive wear was studied for the hypoeutectoid steel, two hypereutectoid tool steels and flame sprayed coatings. In the experiment, the specially designed tester as well as SEM and contact profilometer were applied. Abrasion and erosion remove asperities protruding from the surface of coatings. The imposed stress increased erosive wear of coatings. Application...
Titanium-doped indium oxide (ITiO) films were prepared on soda-lime glass substrate using a magnetic null discharge (MND) sputter source. The ITiO thin films containing 10wt.% Ti showed the minimum resistivity of ρ=5.5×10 −3 Ωcm. The optical transmittance increases from 70% at 450nm to 80% at 700nm in visible spectrum. Photoelectron peaks for In 3d, Ti 2p, O 1s and C 1s were detected for the...
Arsenic, well known of its toxicity, is present in potable water in many areas in the world, as well as in underground water used for water supply in Vojvodina, a region in Serbia. Its removal from raw water is necessary before distribution. In this work two methods of arsenic removal from water are compared. First method is water ozonation by introducing ozone in water and then filtration. Second...
Twenty kHz-range discharge current oscillation with a large amplitude is observed in Hall thrusters, causing unstable operation. In our previous studies, the effects of the anode orifice configuration on the current oscillation have been investigated. Using the results of neutral particle simulations, the relationship between the neutral distribution and the propellant inlet condition was analyzed...
New types of lens-less two-photon ghost imaging experiments are described that can also be useful for 3D X-ray imaging. In these experimental setups, a CCD array is placed facing a chaotic light source and gated by a photon counting detector that simply counts all randomly reflected photons from an object. A “ghost” image of the object is then observed from the gated CCD. A ghost image of an object...
Three-dimensional simulations have been conducted to analyze the wear of ion engine grids. Grid sputtering due to the impact of high-velocity ions and neutrals produced by charge-exchange and elastic collisions between mainstream ions and leaking neutrals was taken into account with redeposition of sputtered grid materials. Comparisons with experiments were performed, and it was found that the calculated...
Annular pupils for electron optics were developed using a focused ion beam (FIB) technique to realize an increase in the depth of focus, aberration-free imaging and separation of amplitude and phase images under scanning transmission electron microscopy (STEM). A tantalum plate 30μm thick was used as the annular pupil material in the present experiment. The annular pupils were designed with various...
Making the angle of a hair clipper blade edge acute improves its cutting ability but causes the edge to be susceptible to wear, resulting in decreased cutting service life. An enhancement of blade edge hardness of hair clippers by various surface modifications has been studied to increase their wear resistance. Ion nitriding method formed a thick nitrided layer on the mother material surface. PVD...
The ion density distribution of plasma sheath in an oblique magnetic field is investigated with a fluid model. We performed numerical simulations of the sheath. The results reveal that the magnetic field has significant effects on the plasma sheath, including ion density distribution and space charge density distribution. Two cases of ion incidence are considered here. Under suitable conditions, Lorentz...
SiC to SiC were reacted by Ti foil at high temperature of 1673K in vacuum. Ti reacted with SiC, and formed many reaction phases between SiC and Ti. At 1673K SiC reacted at a reaction time of 0.5ks or longer. From the SiC many reaction zones of Ti 3 SiC 2 , Ti 5 Si 3 C X , Ti 5 Si 3 C X +TiC, and TiC+Ti were formed. Ti binary compound...
A novel analysis of ion currents, which is based on the use of shifted Maxwell–Boltzmann velocity distribution, is applied to quantify the properties of expanding laser-produced plasmas into the vacuum. The ion currents were measured outside the critical zone where the recombination and collisional excitation processes are not important and the charge-states of ions are frozen. The deconvolution of...
The charge exchange (CEX) ions by the collisions between energetic ions and slow neutral particles in a Hall thruster plume are thought a source of the ions coming back to the satellite. Therefore, mechanical plume shielding has been proposed to prevent the CEX ions from spreading out from near exit region. In order to optimize the shield length, CEX reactions in the plume were evaluated. Number density...
Micro flash butt welding of super duplex stainless steel with Zr-based metallic glass insert was carried out. Zr 55 Cu 30 Ni 5 Al 10 of Zr-based metallic glass with thickness of 50μm and Zr metal with thickness of 500μm were used as the insert materials. After welding, Zr-based metallic glass insert became much thinner than that of Zr metal insert. The supercooled liquid...
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