Angular distribution of plasma in the vacuum arc ion source

This paper presents measurements of the angular distribution of the plasma components and different charge states of metal ions generated by a MEVVA-type ion source and measured by a time-of-flight mass-spectrometer. The experiments were performed for different cathode materials (Al, Cu, and Ti) and for different parameters of the vacuum arc discharge. The results are compared with prior results reported by other authors. The influence of different discharge parameters on the angular distribution in a vacuum arc source is discussed.     

The burst character of thermoelastic shape-memory deformation in crystals of Cu-Al-Ni alloys

We have revealed and investigated the burst character of shape-memory deformation (SMD) in crystals of Cu-13.6 wt % Al-4.0 wt % Ni alloys. We have found that, after giving SMD to 8% when compressed in the direction of the [100] axis and subsequent heating on the solid base with an additional weight of 400 g, the system can rebound up to a height of 55 mm at a speed of ≈1 m/s. The calculations showed that, in the absence of load, a crystal with a weight of 0.8 g (in on absence of air friction) can rebound to a height of 27.5 m with a velocity of 23 m/s when rising from the base. The mechanism of such an unusual behavior of shape-memory deformation in this alloy was studied.     

Preparation of concentrated alkali solutions of niobium

Concentrated alkali solutions of niobium containing up to 238 g/L of Nb₂O₅ have been obtained by sintering of Nb₂O₅ with K₂CO₃ · 1.5 H₂O. These solutions are recommended for use in the production of welding and other functional materials.     

Online Scheduling FIFO Policies with Admission and Push-Out

We consider the problem of managing a bounded size First-In-First-Out (FIFO) queue buffer, where each incoming unit-sized packet requires several rounds of processing before it can be transmitted out. Our objective is to maximize the total number of successfully transmitted packets. We consider both push-out (when a policy is permitted to drop already admitted packets) and non-push-out cases. We provide worst-case guarantees for the throughput performance of our algorithms, proving both lower and upper bounds on their competitive ratio against the optimal algorithm, and conduct a comprehensive simulation study that experimentally validates predicted theoretical behavior.     

A combined physicochemical and electrocatalytic study of microwave synthesized tungsten mono-carbide nanoparticles on multiwalled carbon nanotubes as a co-catalyst for a proton-exchange membrane fuel cell

Tungsten mono-carbide (WC) nanoparticles supported on multiwalled carbon nanotube (MWCNT) was synthesized by a microwave-assisted solid-state carburization. The prepared samples were used as a co-catalyst to prepare Pt-WC/MWCNT catalyst for a proton-exchange membrane fuel cell. MWCNTs with and without oxidative pretreatments were characterized as the starting precursors. The influence of the carbide formation conditions on the physicochemical characteristics of the final product were extensively investigated. According to the results, surface pretreatment of the MWCNTs can improve the yield of carbide formation. Furthermore, carburization process can improve the catalyst utilization due to increasing the number of surface defects of the MWCNT supporting materials which can be interpreted as structural effect of the carburization process. It is believed that the superior performance of electrodes modified with tungsten carbide is mostly due to the structural effect of the carburization process and synergistic effect between the electrocatalytic activity of WC and Pt.     

Degassing of pipe steels under the conditions of KKTs OAO MMK

The relations for the determination of the required hydrogen content under various conditions are determined. The required parameters of steel degassing are found to achieve the optimum hydrogen content.     

Optimizing the Technology of Titanium Phosphate Adsorbent Synthesis from Sulfate-Containing Titanium(IV) Solutions

Theoretical Foundations of Chemical Engineering - An important state in the technology of a compositional silicon-containing titanium phosphate adsorbent is studied. The conditions of washing of...