Papers by Keyword: Porous

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Authors: Mitsuru Takemoto, Shunsuke Fujibayashi, B. Otsuki, Tomiharu Matsushita, Tadashi Kokubo, Takashi Nakamura
Abstract: Generally, characterizations of pore structures of porous biomaterials are mainly based on 2-dimensional (2-D) analysis using cross sectional micrographs. However, interconnectivity of each pore may be more important factor, when tissue ingrowth into deeper pores is considered. In this paper, using micro-CT imaging with 3-D image processing software, analyses of porous material based on 3-demensional (3-D) geometrical considerations were successfully performed. Plasmasprayed porous titanium implant (PT) and four types of sintered porous titanium implants (ST50- 200, ST50-500, ST70-200, and ST70-500) that possess different porosities (50% and 70%) and pore sizes (200-500+m and 500-1500+m) were analyzed in this study. A micro focus X-ray computed tomography system was employed to acquire microstructural information from the porous implants. Using 3-D image processing software, we performed three types of 3-D analysis including detection of the dead space (% dead pore), analysis of interconnectivity by blocking the narrow pore throat with caliber less than 52 +m (% pore with narrow throat) and analysis of material construct by contracting thin strut with thickness less than 52 +m (% construct with thin strut). ST50S and ST50L possessed interconnected porous structure with thicker strut; however, pore throat was considered to be relatively narrow. On the other hand, PT implant possesses favorable interconnectivity despite its’ low porosity; however, relatively thin strut indicate the structural disadvantage for mechanical property. These results suggest that the 3-D analysis of pore and strut structure using micro focus X-ray computed tomography and 3-D image processing software will provide effective information to develop porous implant.
Authors: Yue Ke, Catherine Moisson, S. Gaan, R.M. Feenstra, Robert P. Devaty, Wolfgang J. Choyke
Abstract: The effects of initial surface morphology on the early stages of porous SiC formation under highly biased photoelectrochemical etching conditions are discussed. We etched both Si-face and C-face polished n-type 6H SiC with different surface finishes prepared either by mechanical polishing or by chemical mechanical polishing at NOVASiC. For both Si-face and C-face porous SiC samples, a variety of surface and cross sectional porous morphologies, due to different surface finishes, are observed. The proposed explanation is based on the spatial distribution of holes at the interface of the SiC and electrolyte inside the semiconductor.
Authors: Jian An Liu, Mei Mei Zhang, Xue Na Yang
Abstract: A novel porous ferromagnetic glass-ceramic has been synthesized with glassceramic and hydroxyapatite for hyperthermia application. The glassceramic was obtained from a melt derived glass, and the hydroxyapatite was prepared via precipitation method with biological template (YEAST). Both components of such a mixture were sintered at 1000 °C for 1 hour in graphite. The sample was characterized by x-ray diffraction, scanning electron microscopy and magnetic measurements. This material exhibited magnetic behavior and porosity. The results show that porous ferromagnetic glass-ceramic, which saturation magnetization (Ms) of about 25 A·m2/kg and diameter of porous 30-50μm, was obtained.
Authors: M.S. Mohammed Yahya, Jeyashelly Andas, Ghani Zaidi Ab
Abstract: In this study, highly porous activated carbon was prepared from Cyrtosperma chamissonis petioles via single step H3PO4 activation. The effect of impregnation temperature (RT – 90 °C) on the yield, porosity and surface area was investigated. The synthesized activated carbons were characterized by Na2S2O3 volumetric method, SEM/EDX and N2 adsorption-desorption analyses. The optimization investigation clearly showed that the impregnation temperature affected on the yield and the specific surface area of the materials. Under the optimum impregnation temperature of 75 °C, the registered iodine number and BET surface area were 1129.23 mgg-1 and 1390.41 m2g-1 respectively with yield percentage of 35.82. This preliminary study proves the successful conversion of plant waste into value added porous materials.
Authors: Putra Jaya Ramadhansyah, Mohd Yusak Mohd Ibrahim, Hainin Mohd Rosli, Mohd Haziman Wan Ibrahim
Abstract: Porous concrete technology has been used since 1970s in various parts of the United State as an option to complex drainage systems and water retention areas.Porous concrete pavements have become popular as an effective stormwater management device to control the stormwater runoff in pavement. The objective of this paper is to study a pre-review on Porous concrete pavement and it previous laboratory study. From the literature, it was found that, the strength of the porous concrete pavementstill need to improve. To improve the strength of the porous concrete, various additive have been study as a part of porous concrete mix and yetthe optimum condition to produce good porous concrete still not been established. From the previous study, it was found that to prepare the porous concrete laboratory specimen, the use of standard Proctor hammer (2.5kg) and Pneumatic press (70 kPa compaction effort) resulted in the closest properties to the field porous concrete.
Authors: Y. Shishkin, Yue Ke, Robert P. Devaty, Wolfgang J. Choyke
Abstract: A brief historical development of porous SiC and GaN is given. SEM images of nine porous morphologies in 4H, 6H and 3C SiC are shown along with anodization details. Similarly, two porous GaN morphologies are presented. Applications and future prospects are discussed.
Authors: W.H. Lee, Y.H. Kim, N.H. Oh, Y.W. Cheon, Y.J. Cho, C.M. Lee, K.B. Kim, N.S. Lee
Abstract: Coatings of hydroxyapatite (HA) on the porous-surfaced Ti compact have been conducted by electrostatic spray deposition (EDS). The precursor solution for the HA coating by ESD was prepared by mixing nano-scaled HA powder with ethyl alcohol. As-deposited HA films on the substrate were heat-treated (400 ~ 900 °C) and their physical characteristics were investigated by Scanning Electronic Microscopy (SEM), X-ray Diffractometer (XRD), and X-ray Photoelectronic Spectroscopy (XPS). As-deposited HA films were consisted of HA particles which were uniformly distributed on the Ti substrate, showing a porous structure. By heat treatment, HA particles were agglomerated each other and melted to form a highly dense and homogeneous coating layer consisted of equiaxed nano-scaled grains. HA coatings on the porous-surfaced Ti compact consisted of highly crystalline apatite phase with the Ca/P ratio of about 1.67 were successfully obtained by using ESD.
Authors: T. Zaharinie, Farazila Yusof, Mohd Hamdi Abdul Shukor, T. Ariga
Abstract: In this study, a Cu/Ni porous composite was introduced when brazing sapphire to Inconel 600 using a special active filler metal of BAg-8 + 2Ti. The aim of the research is to investigate the Ti distributionin the Cu/Niporous composite and braze joint. The brazing was carried out in brazingtemperature of 830°C for 30 minutes by a vacuum environment (10-4 Pa). The interface of braze joint/sapphire and braze joint/Inconel 600 were observed by an electron microscope followed by elements analyzing using SEM-EDS. The observation and analysis shows that there is a black and thin reaction layer at braze joint/sapphire interface and a non-uniform of reaction layer was formed at braze joint/Inconel 600 interface. The formation of reaction layer is influenced by thermodynamic activity of Ti during brazing.
Authors: Takashi Ushida, Tamotsu Tamaki, Guo Ping Chen, Yoshikazu Umezu, Tetsuya Tateishi
Authors: Zulaila Abdullah, Rosliza Razali, Istikamah Subuki, Mohd Afian Omar, Muhammad Hussain Ismail
Abstract: NiTi is categorized as a Shape Memory Alloy (SMA) that has been commercially studied and used in biomedical industry due to two main unique properties, Pseudoelastic (PE) and Shape Memory Effect (SME). Combined with biomimetic properties to human bone, NiTi has the potential to be applied as implants by engineered manufacturing process. The common manufacturing by casting has some challenges in order to obtain intrinsic and miscellaneous design of NiTi parts leash to explore more using powder metallurgy (PM) method that expected to get the porous structure. This paper aims to provide an overview of processing NiTi by conventional PM method which could contribute in focusing porous part that suits for biomedical and implants.
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