Enhancing a service life of torch components for MIG/MAG welding

The paper analyzes the main vulnerable elements of torches used in mechanized gas-shielded welding. Particular attention is given to the gas nozzle designs, materials they are made of, and other welding torch elements exposed to increased electrical and thermal stresses during the welding process

The influence of mineral fillers on mechanical properties of polyvinyl chloride composites

The paper reports the investigation results of tensile stress-strain properties of filled PVC composite during static and low cycle testing. The distinctive features of composite mechanical behavior depending on the content of dispersed mineral fillers which are basically industrial waste are established. It is revealed that small filler additives have a strong influence on the structural behavior that manifest itself as their abnormal change depending on the filler content. The experimental data obtained are explained based on the modern ideas about structural morphological model of base polymer structure. © IDOSI Publications, 2013

Temperature change calculation at welding products

Thermal calculation of the welded seams was conducted, made from heat resisting austenitic steel 10X11H20T2P by argon-arc welding. Schedules of temperature increment are constructed during various time moments on mode parameters existing on technology manufacture and on offered welding conditions. Structure forecasting opportunity and mechanical properties of welded connection various zones is shown: a welded seam, weld lines, zones of thermal influence and basic metal by calculation of temperature field changing in time. Calculation data are received at use of standard methods of calculation and under general formulas. Basic methods of experimental temperature test are considered at welding and computer application in calculations of temperature fields. Recommendations are given at the welding modes choice for prevention of hot cracks formation, namely, welding speed reduction up to 6 km/h is recommended. © IDOSI Publications, 2014

Donor-acceptor recombination emission in hydrogen-terminated nanodiamond: Novel single-photon source for room-temperature quantum photonics

In fluorescence spectra of nanodiamonds (NDs) synthesized at high pressure from adamantane and other organic compounds, very narrow (~1 nm) lines of unknown origin are observed in a wide spectroscopic range from ~500 to 800 nm. Here, we propose and experimentally substantiate the hypothesis that these mysterious lines arise from radiative recombination of donor-acceptor pairs (DAPs). To confirm our hypothesis, we study the fluorescence spectra of undoped and nitrogen-doped NDs of different sizes, before and after thermal oxidation of their surface. The results obtained with a high degree of confidence allowed us to conclude that the DAPs are formed through the interaction of donor-like substitutional nitrogen present in the diamond lattice, and a 2D layer of acceptors resulting from the transfer doping effect on the surface of hydrogen-terminated NDs. A specific behavior of the DAP-induced lines was discovered in the temperature range of 100-10 K: their energy increases and most lines are split into 2 or more components with decreasing temperature. It is shown that the majority of the studied DAP emitters are sources of single photons, with an emission rate of up to >1 million counts/s at room temperature, which significantly surpasses that of nitrogen-vacancy and silicon-vacancy centers under the same detection conditions. Despite an observed temporal instability in the emission, the DAP emitters of H-terminated NDs represent a powerful room-temperature single-photon source for quantum optical technologies

Resource-efficient low-loss four-channel active demultiplexer for single photons

We report a design and implementation of a resource-efficient spatial demultiplexer which produces 4 indistinguishable photons with efficiency of 39.7% per channel. Our scheme is based on a free-space storage/delay line which accumulates 4 photons and releases them by a controlled polarization rotation using a single Pockels cell.Comment: 8 pages, 7 figure