材料科学および工学ジャーナル

The dynamic emitter-a nozzle with a disposed along its axis central conic body-is a new engineering decision. The phenomena arising during its work are valuable and prospective both in fundamental science and practical application. During our experiments with this device we have discovered spiral-twisted non-ideal plasma wave structures arising in subsonic and supersonic gas jets flowing from the nozzle with a central cone. We consider very important and prospective the fact that the flow from the dynamic emitter remains almost stable both in shape and power with the distance from the nozzle outlet increasing. For example, the air jet from the nozzle with a central cone can deflect a steel plate of weight 2.55 kg, pending on the 120 mm wire, for about 45 mm at the distance of 400 mm. At this distance the power of the flow from the common conic nozzle is insignificantly low. Also in our experiments we registered phase transitions of air, argon and nitrogen to liquid and solid in the jets at room conditions (temperature of the jet was 285 K, humidity about 5-7%), which is very unusual and provides a lot of practical opportunities. Water vapor flowing from the dynamic emitter creates the mentioned non-ideal plasma structures with increased density of electrons that provides concentration of energy in small volumes (in the nodes of the structure) and high energy radiation (in the experiments there were detected electromagnetic fields up to 1 GHz). The received results can be explained with introducing the concept of electromagnetic super-compressibility which has been the primary aim of our work.

Conversion of Crumb Rubber Tires (CRT) and waste plastics to functional materials has been shown in this research study as a feasible approach for the improvement of some physical properties of asphalt. The rheological study of the modified asphalt is made through softening point temperature, penetration point, and viscosity tests.
In the present study, CRT and Low Density Polyethylene (LDPE) (plastic wastes) were chosen to be the materials of choice to blend with the virgin asphalt. The reclaimed rubber in the form of powder having a particle size below 0.8 mm was used as an additive to liquid asphalt using the Hot Mix Asphalt Process (HMA) at 180.0 ± 2.0°C with a high-speed stirrer rotating at a speed of 3000 rpm for 60 min. For a consistent mix, the blending operations were performed with different CR and LDPE contents; they were 3.0%, 5.0%, 10.0% and 15.0% by weight. LDPE-CR composite was also added to the virgin asphalt at 1:1, 1:1.5, 1:2, and 1:3 ratios. The results of this research study have indicated that these modified asphalt patterns are characterized by having softening point temperatures and penetration points leading to suitable Penetration Indexes (PI) in comparison with virgin asphalt binder. The viscosity of virgin asphalt was also enhanced with the addition of additives. Best results were obtained when CR, LDPE, and CR-LDPE composite concentrations were attained below 10.0% with most at 5.0%. Determining the number and identities of components in the modified asphalt mixture by Thin Layer Chromatography (TLC) and phase distributions of micrographs from Scanning Electron Microscopy (SEM) was also studied.

Cockle shell CaCO3 bioceramic is potential for multiple tissue engineering applications. The powder was produced by cleansing the cockle shells to remove all the dirt from the shell’s surface followed by crushing them into CaCO3 powder. The powder was characterized using X–Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Analyser (EDXA) and Fourier Transform Infrared (FT-IR). Aragonite phase was observed in cockle shell CaCO3 powder and calcite phase was observed in commercial CaCO3 by XRD. SEM analysis revealed the structure of cockle shell CaCO3 powder to be rod-like aragonite crystals whereas commercial CaCO3 had cube-like calcite crystals. The EDX outcomes showed that the cockle shell CaCO3 powder had more carbon and oxygen as compared to commercial CaCO3. FT-IR results also attested aragonite phase in cockle shell CaCO3 powder and it also showed the existence of carbonate groups in cockle shell CaCO3 powder as well as commercial CaCO3 powder.

In the current study, the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption, which were fabricated from Kevlar, carbon, glass fibres, and resin have been experimentally investigated at the high velocity ballistic impact conditions. All the samples have equal mass, shape, and density, nevertheless, they have different stacking sequence layers. After running the ballistic test in the same conditions, the final velocities of the bullets showed that how much energy absorbed by the samples. The energy absorption of each sample through the ballistic impact has been calculated, accordingly, the decent ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterize the material properties.