The paper presents investigations into thermophysical, rheological, and morphological properties of graphitized carbon nanotube/polyoxymethylene composites containing 30 wt.% graphite and 0.1 wt.% ...nanotubes. It is shown that thermal conductivity and thermal diffusivity of graphitized carbon nanotube/polyoxymethylene composites increase respectively by 8 and 11 times in comparison with the original polyoxymethylene. And their melt flow index reduces approximately by 3.5 times. In spite of the abrupt decrease in the melt flow index, graphitized carbon nanotube/polyoxymethylene composites can be used in extrusion, jet molding and three-dimensional printing.
The possibility is studied of preparing polymetal specimens of Ti and Ti–6Al–4V by direct laser deposition. The microstructure of deposited specimen zones given heat treatment shows a transition zone ...from (α+β) phase from the side of Ti–6Al–4V alloy to α-phase from the Ti side. No cracks are observed within the structure. With a change-over from Ti–6Al–4V to Ti microhardness varies from 380 to 200 HV.
Computer simulation methods have been applied to study the processes of low-temperature ceramics synthesis corresponding to technological processes. The simulation is performed for micron- and ...nanosized powders with different morphology. The synthesized composite medium has the characteristics (microlayer thickness, pore volume fraction, etc.) that reflect imperfections in the initial dispersion. The developed model allows one to examine the governing factors of physical and chemical processes in low-temperature ceramics synthesis.
The applicability of electrolytic plasma surface polishing to complex components produced by selective laser melting (SLM) is analyzed. By electrolytic plasma polishing by electrolyte spraying, the ...surface quality of components produced by SLM may be improved. This technology is found to decrease the surface roughness from
R
a
= 5.6 μm to 1.4 μm. The optimal pressure of the electrolyte jet is 0.02–0.05 MPa. At high pressures, the process becomes unstable. By electrolytic plasma polishing on the basis of electrolyte jets, uniform external and internal surface roughness of components produced by SLM may be ensured.
Currently, direct laser deposition is a key research area since use of this technology is distinguished by cheapness and the possibility of preparing an object of almost any shape. However, numerous ...aspects of material manufacturing technology and structure formation remain unstudied. The process of preparing polymetallic specimens consisting of layers of alloys Inconel 625 and EP741 is considered. A polymetallic specimen microstructure is extended nickel solid solution crystals. Element distribution in a grain boundary zone shows a smooth change in composition as a result of element diffusion from Inconel 625 alloy into EP741, and conversely. Layer microhardness varies from 300 to 500 HV with transition from Inconel 625 alloy into EP741
The change in morphology of polygonal powder in a low-temperature plasma generated in an arc discharge is an effective means for resolving the problem of preparing titanium alloy powder of spherical ...shape used in additive technology. A method is studied for preparing spherical powder of titanium and its alloys by spheroidization in streams of a polygonal powder thermal plasma, prepared by hydrogenation-dehydrogenation. A production scheme is proposed for preparing spherical titanium alloy powder for additive technology, including remelting of certified waste, ingot hydrogenation, crushing, screening its fractions, dehydrogenation, and gas centrifugal classification with final plasma treatment. A technology is developed for preparing spherical titanium alloy powder used in additive technology, with a reduced dissolved gas content. Methods are considered for improving the quality of spheroidized titanium powder including: minimization of the amount of particles with size less than 10 μm in the original polygonal powder, a change in composition of the plasma-forming gas, and prevention of contact with air by powder before and after spheroidization.
A dynamic stochastic general-equilibrium (DSGE) model with real and nominal, both price and wage, rigidities succeeds in capturing some key nominal features of U.S. business cycles. Additive ...technology shocks, as well as multiplicative shocks, are introduced and shown to be crucial. Monetary policy is specified as an interest rate targeting rule following developments in the structural vector autoregression (VAR) literature. The interaction between real and nominal rigidities is essential to reproduce the liquidity effect of monetary policy. The model is estimated by maximum likelihood on U.S. data, and its fit is comparable to that of an unrestricted first-order VAR. Besides producing reasonable impulse responses and second moments, this model replicates a feature of U.S. business cycles, never captured by previous research with DSGE models, that an increase in interest rates predicts a decrease in output two to six quarters in the future.
Food industry is craving to develop new technologies and processes which will satisfy customers’ ambiguous wishes but also specific dietary needs. In 21st century, food allergies or food intolerances ...are affecting population from nurseries up to elderly stages while causing people, not only health issues but also making their nutrition plans and grocery shopping challenging and expensive. Three dimensional (3DP) food printing is a potential solution to advance current food processing techniques, but also to integrate 3DP and digital gastronomy technique to customize food products. If applied in domestic cooking or catering services, 3DP can provide an engineering solution for customized food design and personalized nutrition control, but also has the potential to redefine food supply chains. Still, people might be doubtful to eat 3D printed food due to their perception that it does not taste as good as traditional food and it appeals almost over-processed and artificial. This paper gives the short overview on 3DP techniques, devices and ingredients used for 3DP, as well as the possible future application in food manufacturing.
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