Punto Dewo

Effect of cold working and sandblasting on the microhardness, tensile strength and corrosion resistance of AISI 316L stainless steel

The aim of this work is to investigate the effect of cold working and sandblasting on the microhardness, tensile strength and corrosion rate of AISI 316L stainless steel. The specimens were deformed from 17% to 47% and sandblasted for 20 min using SiC particles with a diameter of 500–700 μm and an air flow with 0.6–0.7 MPa pressure. The microhardness distribution and tensile test were conducted and a measurement on the corrosion current density was done to determine the corrosion rate of the specimens. The result shows that the cold working enhances the bulk microhardness, tensile and yield strength of the specimen by the degree of deformation applied in the treatment. The sandblasting treatment increases the microhardness only at the surface of the specimen without or with a low degree of deformation. In addition, the sandblasting enhances the surface roughness. The corrosion resistance is improved by cold working, especially for the highly deformed specimen. However the follow-up sandblasting treatment reduces the corrosion resistance. In conclusion, the cold working is prominent to be used for improving the mechanical properties and corrosion resistance of AISI 316L stainless steel. Meanwhile, the sandblasting subjected to the cold worked steel is only useful for surface texturing instead of improving the mechanical properties and corrosion resistance.

Three Dimensional Morphometry of Distal Femur to Design Knee Prosthesis for Indonesian Population

El objetivo fue disenar una protesis a medida para una determinada poblacion, por tanto la morfometria debia ser medida para proporcionar datos basicos para disenar el tamano ideal de una protesis total para la artroplastia de rodilla en poblacion de Indonesia. Se realizo un estudio antropometrico sobre 100 sujetos sanos indonesios, basados en tomografias computadorizadas (TC) de la superficie resecada del femur distal. Los parametros que se midieron fueron longitud femoral mediolateral (FML), longitud femoral anteroposterior (FAP), longitud femoral medial anteroposterior (FMAP), longitud femoral lateral anteroposterior (FLAP), y razon de aspecto femoral (FR). Las medias FAP y FML fueron 54,60±5,71 y 65,98±6,51, respectivamente. La morfometria del femur distal fue significativamente diferente entre hombres y mujeres (mayor tamano en hombres), sin embargo uno de los parametros mostro resultados diferentes, la FLAP. Las personas indonesias son de menor tamano en comparacion con su contraparte occidental. Las dimensiones propuestas se pueden utilizar como los datos basicos para disenar el tamano ideal para una protesis de rodilla a medida para la poblacion de Indonesia.

Three Dimensional Morphometry of Proximal Femur to Design Best-Fit Femoral Stem for Indonesian Population

Para disenar protesis a medida en una poblacion determinada, la morfometria necesita ser conocida. El objetivo de este estudio fue obtener resultados que sean utiles en la investigacion para disenar el tamano ideal de una protesis total de artroplastia de cadera para la poblacion de Indonesia. Fue realizado un estudio antropometrico en 100 sujetos sanos de raza mongoloide de Indonesia, en los que se estudio la parte proximal del femur por tomografia computadorizada (TC). Se consideraron como parametros la cabeza del femur (CF), posicion de la cabeza del femur (PCF), diametro de la cabeza del femur (DCF), angulo cervicodiafisario (ACD), ancho anteroposterior (AAP) y ancho-lateral en 3 lugares diferentes. La poblacion Indonesia tiene una morfometria menor del femur proximal en comparacion con la poblacion occidental. El valor medio de todos los parametros en hombres fueron mayores a las mujeres. Por otra parte, CF y PCF mostraron diferencia significativa entre hombres y mujeres e indico una ubicacion superior del centro de la cabeza del femur en hombres, en comparacion con las mujeres. Se encontro que la dimension del canal femoral fue mediolateral oval, 1,43, 1,28, y 1,34, en 3 cortes diferentes, respectivamente (20 mm superior y 40 mm inferior del trocanter menor e istmo). La dimension del femur proximal en la poblacion de Indonesia es de menor tamano en comparacion con la contraparte occidental. Las dimensiones propuestas se pueden utilizar como datos basicos para el diseno de un tamano ideal de vastago femoral para la poblacion Indonesia.

The effect of annealing temperature on the physical and mechanical properties of stainless steel 316L for stent application

A comparative study on mechanical properties and microstructure of 316L austenitic stainless steel annealed in different temperatures were presented. The objective of this study was to get the optimum annealing temperature for austenitic stainless steel 316L for stent application in coronary heart disease. Five groups of specimens (ASTM E8-2004) were annealed in the electric furnace (Ellite Thermal System Ltd., UK) at temperature 1000°C, 1050°C, 1100°C, 1150°C, and 1200°C using a heating rate of 5°C/min with 30 minutes holding time. The heat-treated austenitic stainless steel 316L was cooled to room temperature by slow furnace cooling then collected and characterized. The microstructure evolution of every sample was observed using SEM. The hardness of the sample was measured using Vickers micro hardness test. The universal testing machine was used to measure the tensile strength and elongation of every sample. The results shown that the biggest elongation of austenitic stainless steel 316L is obtained when the material is annealed at temperature between 1050 to 1150°C.

Study on X-ray diffraction, infra-red spectroscopy, and microstructure of CoHA-Gelatin-PVA biocomposite

The aim of this study was characterization of Biocomposite CoHA-Gelatin-PVA. CoHA (Calcite Omya Hydroxyapatite was obtained from local material by synthesizing local calcite, while gelatin and PVA was commercial from Merck. The composite was prepared by blending powder of CoHA, gelatin, and PVA with weight ratios of 1∶1∶0.15. This blended powder composite was then mixed with distilled water with various solid loading of 5, 15, and 25% w/v. Next, it was cooled at freezer prior freeze drying to build a porous block composite. Characterization was carried out by XRD, FTIR, and SEM. The results showed that the composite block has micropore size <10 and macropore up to 300 µm. Results showed that the HA-gelatin-PVA can be synthesized into porous biocomposites, which has the potential for bone graft. The biocomposite has low cristallyne structure and there is a complex network structure of HA-gelatin-PVA. Biocomposites have a macropore up to 300 µm and micropore up to <10 µm.

Development and Characterization of Bovine Hydroxyapatite Porous Bone Graft for Biomedical Applications

The porous Hydroxyapatite (HA) ceramics have found enormous use in biomedical applications including bone tissue regeneration, cell proliferation, and drug delivery. This paper investigates the preparation and characterization of bovine Hydroxyapatite (BHA) porous bone graft by mixing sucrose powder as porogens with bovine bone powder. After uniaxially pressing at 156 MPa and pressurelessly sintering in air atmosphere at 1200°C for 2 hours the bioceramic showed an interconnecting porosity. The XRD analysis indicated that bovine hydroxyapatite (BHA) porous bone graft resulted in this research is single phase HA and is believed to be pure HA as indicated by the peak of the diffraction patterns (JCPDS 9-432). The phase analysis also shows that BHA porous bone graft is highly crystalline with domain crystallites sizes are between ~46 to ~99 nm (~4.6 to ~9.9 Å). Several trace elements in human bone such as titanium (Ti), iron (Fe), nickel (Ni), copper (Cu) and Zinc (Zn) were also detected in BHA porous bone graft as indicated by SR-XRF. This object is promising for bone regeneration because the interconnecting porosity in carbonated apatite provides a good environment for bone attachment and ingrowths

Orthopedic Equipment Needs in Disaster Setting

In mass-casualty events, such as natural disasters, surgical assets and resources could be damaged or become unavailable; hence, they need to be delivered by a disaster relief team. Disaster relief team should work with the goals according to the time of intervention and based on the attainment of reliable information regarding what is required [1].

Functional Outcome of Galeazzi Fractures Treated by ORIF and DRUJ Stabilization either Using Long Arm Cast or Transfixing Wire

Introduction: Galeazzi fracture is a condition where there is distal radial shaft fracture accompanied with disruption of the Distal Radioulnar Joint (DRUJ). Assessment of distal radio ulnar joint stability is mandatory and followed by further joint stabilization methods. The aim of this study was to study the functional outcome Galeazzi fracture management treated with ORIF followed by DRUJ strabilization using transfixing wire with long arm splint compared with long arm cast. Materials and methods: This study was a cross sectional observational study in patients with Galeazzi fractures from January 2007 to May 2012 underwent ORIF and DRUJ stabilization either using long arm cast or transfixing wire and long arm splint. Functional outcome measurement started at 3 months after surgery. The researcher contacted those eligible patients. After patients gave consent to the study, they were asked to do an interview guided by the researcher using QuickDASH score. The data was analysed using Fisher Exact test. Results: A total of 32 patients with Galeazzi fracture underwent ORIF followed by DRUJ stabilization. 72% had good functional outcome in subjects underwent ORIF followed by transfixing wire with long arm splint and 79% subjects using long arm cast (p-value>0.05). Conclusion: This study showed that Galeazzi fracture patients treated with ORIF followed by long arm cast or transfixing wire and long arm splint had not significantly differ and had equally good functional outcome results.

Contouring posterior and lateral tibia of javanese people based on X-Rays images

Osteosynthesis plates provide a rigid and stable fixation for bone fracture treatment. The bone stability during the fixation period is determined by the conformity between the bone and plate. The plate fits well to the bone if it is designed based on the bone contour. Hence, the contour profile of bone must be determined prior to designing the plate. The aim of this work is to perform a contouring technique for human tibia and then to formulate the results into a mathematical model. Samples were 2D X-rays images of five tibia from Javanese people. The data was well fitted to the Rational Chebyshev equation.