Advanced Materials Research Vol. 902

Abstract: With the adoption of surface modification method, microencapsulated phase change materials (MEPCM) with polyurea as wall materials, paraffin as core materials were successfully prepared. This paper made a research on the effect dosage of modifier might have on the content of microcapsule core materials. Findings indicated that the content of microcapsule core materials was relatively high as the dosage of modifier being core material 10 wt%. It was preliminarily proved that polyurea had been coated on the surface of paraffin particles by adopting Fourier Transform Infrared Spectrum (FTIR) to formulate the composition and structure of microcapsules. And the laser particle analysis declared that particle size distribution of microcapsules was narrow with average particle size of 389 μm. Thermo Gravimetric Analysis (TG) and Differential Scanning Calorimetry (DSC) were also employed to make a representation of the thermal properties of microcapsules, and it was shown that microcapsules were of wonderful phase change performance and thermal stability.

Abstract: The drilling damage forms of hole wall is presented and the reasons for drilling quality are analyzed in drilling carbon fiber reinforced plastics. Based on the study of experiments, the relationship between the drilling damage and the drilling parameters are obtained. The results indicate that the drilling hole wall forms drawn fiber and fallen off fiber bundle more easily and the surface roughness of hole wall becomes worse with the increase of the spindle speed, and the final drilling surface presents obvious anisotropy. In order to obtain good drilling quality, lower spindle speed should be selected on the premise of lower feed rate.

Abstract: The β nucleated polypropylene (PP), uncompatibilized β nucleated PP/polystyrene (PS) and compatibilized β nucleated PP/PS blends were prepared on a twinscrew extruder.and then,added into compatibilizers styrene-ethylene-propylene block copolymer (SEP) or twostyrene-ethylene-butylene-styrene block copolymers (SEBS) with different content of styrene.The morphology and mechanical properties of these composites were investigated.

Abstract: With higher cleanness upgraded steadily, surface failure of metallic materials in very high cycle fatigue (VHCF) regime beyond 10⁷ cycles has been reported one after another. The occurrence of surface crack initiation to failure in VHCF regime is closely related to the following factors: (i) surface finishing condition of specimen, i.e. whether some grinding scratches, grooves and cavities with a relatively larger size than the subsurface defect exist at the surface of specimen; (ii) type, size, location, distribution and density of metallurgical defects such as inclusion contained in the subsurface of material; (iii) degree of persistent slip band (PSB) deformation induced by surface roughening of specimen, mainly corresponding to the some ductile single-phase metallic materials.

Abstract: Melatonin, encapsulated and non-encapsulated, in a topical gel, was comparatively investigated for its in vitro permeation and in vivo anti-inflammatory properties. An average size of the melatonin-encapsulated niosomes of 197 nm with a zeta potential of-78.8 mV and an entrapment efficiency of 92.7% was incorporated into a gel base. In vitro skin permeation of the same gel base incorporated with non-encapsulated melatonin or melatonin niosomes at 5% was comparatively evaluated through porcine skin using Franz diffusion cells and analyzed by spectroflurometry at λ_ex 278 and λ_em 348 nm. From the same gel base, the permeation rate of non-encapsulated melatonin was about 2.5 times greater than that of melatonin-encapsulated niosomes. In comparison to piroxicam gel and hydrocortisone cream used as the positive controls, topical applications of melatonin and melatonin niosome gels tested in croton oil-induced ear edema in mice suggested that its anti-inflammatory activities were prolonged by the niosomal encapsulation. Similarly, analgesic effect of melatonin was prolonged by niosomal encapsulation using tail flick test in mice. Therefore, its immediate permeation through the skin was retarded by niosomal encapsulation which could also prolong its rapid decline in exerting anti-inflammatory and analgesic activities in vivo.

Abstract: Jatropha curcas oil (JCO) is a good option as renewable energy for biodiesel and as lubricant feedstock. In México, the JCO is widely distributed in more than 15 states. This work describes the characterisation of Jatropha curcas oil as additive in engine oil (EO) blended mixtures. The EO and JCO were separately tested using a four balls test rig at 100%. The JCO was added and mixed as an additive to the EO too at 5%-95%, 10%-90%, 15%-85%, 20%-80%, and 50%-50%. The results have shown a steady friction coefficient for the testes carried out at different loads for the different mixtures. The friction coefficients were lower compare to the friction coefficients from the oil engine. Nevertheless, the wear scars were bigger when JCO was used. The results from the oil mixtures showed good potential for the JCO to be used as an additive.

Abstract: The paper describes the principles of carrying out of a new type of fluidized bed thermo-chemical treatment in chemically active powders with fluidization by chemically inert gas. The article presents selected results of a computer simulation of chemically active fluidized bed phenomena used in the thermo-chemical treatment of steel. For this purpose, a numerical model of the fluidized bed with a specific calculation area, has been prepared. The results of CFD (Computational Fluid Dynamics) computer simulation of temperature distribution and fluidizing gas mass distribution along the walls of samples placed in the fluidized bed are presented. Results of exemplary carburizing process are given. Metallographic observations and hardness measurements confirm the correctness of the of the carburized layer structure, which was formed on the C22 unalloyed carbon steel.

Abstract: The understanding of machining processes comprises the study of phenomena such as: chip formation, cutting forces, tool wear mechanisms and the influence of the cutting parameters and machined materials on them. The aim of this work is to analyze the tool wear effects on machining forces during machining of AISI 1040 and 1045 carbon steels with carbide tool. Long-term machinability tests were performed, in which cutting force, feed force and tool wear were measured. Tool life results were analyzed, with best tool lives found for the AISI 1040 steel for all tested speeds. The other variables were analyzed as function of both time and tool wear. On the time domain, strong dependencies were found for both materials for tool wear, cutting force and feed force. The relationship between cutting force and tool wear showed good correlation for both materials, and the same was observed for feed force and tool wear relationship. Weak influence of cutting speed was observed on the relationship between tool wear and machining forces, which suggest that a single equation can describe them for all studied conditions with reasonable accuracy. The regression results are able to predict cutting forces as a function of tool wear with an average error of about 2.6 % during machining of AISI 1040 and 5.2 % for AISI 1045 steel. For the prediction of feed force as a function of tool wear, the average error is about 5.6 % for AISI 1040 and 7.0 % for the AISI 1045 steel, since a restricted domain is established. Data analysis showed a discontinuity in the behavior of feed force as a function of tool wear near the end of the life of the tools for most tests performed with AISI 1045 and some tests with AISI 1040 that suggest backwall wear, which was further evidenced by sudden change of chip form near the end of tool life in AISI 1040 steel.

Abstract: The aim of this work is to analyze the tool wear effects on surface finish of machined components. Long-term machinability tests were performed for ASTM 1040 and 1045 carbon steels with carbide tools, in which tool wear and surface roughness were periodically evaluated. Surface finish was analyzed as a function of processed material and cutting speed with new machining tool, and a significant influence was found for cutting speed at a confidence interval of 10%. When evaluated as a function of time and tool wear, surface roughness showed an exponential relationship with both variables. However, a high dispersion occurs close to the end of tool life, especially for AISI 1040 steel. Weak influence of cutting speed (for the range of speeds tested) was observed on the relationship between tool wear and surface finish, indicating that a single equation can describe its behavior for all studied conditions. The relationship between the surface roughness and the cutting time was found to be stronger for the ABNT 1040 steel.

Abstract: The theoretical optimization of the process was based on our kinetic model of MCH dehydroalkylation with methanol in the presence of HNa TsVM zeolite (SiO 2 /Al 2 O 3 =30) modified with platinum and gallium and gadolinium oxides.