Abstract: The fabrication of Sr hydroxyapatite (HA) porous scaffolds was done by using polymeric sponge method. To prepare the porous samples, the synthesized SrHA nanopowders were mixed with distilled water and appropriate amount of dispersing agent followed by drying in the ambient air and sintering at 1300°C. The compressive strength of the materials was strongly influenced by the porosity, while there was almost no dependence on the crystallinity of the powders since XRD patterns showed high crystallinity of HA phase for all porous samples. Morphological evaluation by FESEM revealed that the SrHA scaffolds were characterized by macro-micro interconnected porosity, which replicates the morphology of the cancellous bone. Compression test on the porous scaffolds demonstrated that doping 10 mol% of strontium in HA has increased the compressive strength by a factor of two compared to the undoped HA with 1.81±0.26 MPa at 41% porosity.
Abstract: The Ni-based superalloy, Inconel 690, was oxidized between 800 and 1000°C for up to 300 h in air. It displayed good oxidation resistance, because the formed scales consisted primarily of Cr2O3. As the oxidation progressed, CrMn1.5O4 also formed on the surface through the ensuing outward diffusion of Mn from the alloy. Internal oxidation occurred below the scale-alloy interface along grain boundaries of the matrix.
Abstract: The Ti (C, N) solid solution is as one particle in most study of Al2O3/Ti (C, N) ceramic materials. In this paper the contents of TiC and TiN will be considered separately, the mechanical properties and microstructures of Al2O3/Ti (C,N) ceramic materials are study in different contents of TiC/TiN and sintering temperatures. It is indicated that the TiC/TiN contents and sintering temperatures have important effect on microstructures and mechanical properties of Al2O3/Ti (C,N) ceramic materials.
Abstract: Residual life is tightly related to the period of examine and repair of pressure vessels. The accuracy of residual life prediction may have a great influence on the reliability and the cost of examine and repair of the in-service pressure vessels containing crack defects. Aimed at the problem of residual life prediction of pressure vessels containing crack defects, we put forward a new method on the basis of crack failure path and rate, which is based on the fracture mechanics and failure assessment diagram (FAD). Though there may be a lot of researches to do, this algorithm is higher in efficiency and easy to calculate, compared to the other methods. This method is original and creative. It provides a new research approach to study the residual life prediction.
Abstract: The morphologies of ZnO nanostructured were synthesized by carbon assisted. The materials source will be prepared by mixing Zn, ZnO and coconut shell charcoal or graphite. The materials source and silicon substrates were put in quartz tube of furnace, heated in difference gases. When, the temperature was cooled down to natural room temperature. The materials sources and silicon substrates will be studied by scanning electron microscope (SEM) and an energy dispersive X-rays instrument (EDX). The results showed that ZnO nanostructures materials such as nanotatrapods, nanowires, nanorods and nanoparticles can be observed.
Abstract: This paper shows a numerical-experimental comparison to validate a mathematical model which is able to determine the superplastic material constants by means of experimental tests carried out using a standard forming die geometry. In particular, the constants m, n and K for the lead-tin alloy PbSn60, for the alloy AZ31 at different forming temperatures and for the alloy AA5083 are evaluated.
Abstract: The mechanical behaviour of a superplastic material is often modelled by the power law relationship between the equivalent flow stress, the equivalent strain and the equivalent strain-rate at least over a limited range of strain rates. This paper introduces an original mathematical modelling to determine the superplastic material constants m, n and K by means of experimental tests carried out using a standard forming die geometry.
Abstract: Replacement or repair of corrosion damaged equipment is the largest maintenance requirement for the industry. One technique for reducing the corrosion of metals is to coat them with thin layers of less reactive metals or alloys. Unfortunately, most metallic coatings are inherently porous and historically have been of little value as barriers against corrosion. Recently, with the development of new alternative material such as electrodeposited CoNiFe, these problems have largely been overcome. This paper investigated the effects of different aggressive environments on the corrosion behavior of electrodeposited CoNiFe. Interestingly, the mixed morphologies with spherical and dendritic structure were found in the neutral and alkaline environment. This morphology exhibited the smallest particle size with less percentage of oxygen elements. Besides, alkaline environment experienced the slowest corrosion rate due to the mixed morphology. It was found that spherical and dendritic refinement provides higher corrosion resistance. The corrosion rate of the sample prepared in alkaline environment was the lowest compared to the others due to the reduction of particle size.
Abstract: Cases of 30 whey protein isolate-sodium caseinate-glycerol composite protein films based on different ingredients and processing techniques, and their packaging properties were analyzed by Q and R cluster analysis, respectively. The results verified that there was a correlation in either 30 cases or 7 indexes of packaging performance, which contributed to a scientific sorting. 30 cases could be divided into 5 groups by Q cluster analysis with the Euclidean distance at 40, in which case 28 and 30 exhibited the highest similarity. On the other hand R cluster analysis in packaging performance indicated that gas permeability and haze values of composite films tended to be more similar than the others.