This paper proposes an improved modeling approach for bone scaffolds biodegradation. In this study, the numerical analysis procedure and computer-based simulation were performed for the bone scaffolds with varying porosities in determining the wall shear stresses and the permeabilities along with their influences on the scaffolds biodegradation process while the bio-fluids flow through within followed with the change in the flow rates. Based on the experimental study by immersion testing from 0 to 72 hours of the time period, the specimens with different morphologies of the commercial bone scaffolds were collected into three groups samples of 30%, 41%, and 55% porosities. As the representative of the cancellous bone morphology, the morphological degradation was observed by using 3-D CAD scaffold models based on microcomputed tomography images. By applying the boundary conditions to the computational fluid dynamics (CFD) and the fluid-structure interaction (FSI) models, the wall shear stresses within the scaffolds due to fluid flow rates variation had been simulated and determined before and after degradation. The increase of fluid flow rates tends to raise the pressure drop for scaffold models with porosities lower than 50% before degradation. As the porosities increases, the pressure drop decreases with an increase in permeability within the scaffold. The flow rates have significant effects on scaffolds with higher pressure drops by introducing the wall shear stresses with the highest values and lower permeability. These findings indicate the importance of using accurate computational models to estimate shear stress and determine experimental conditions in perfusion bioreactors for tissue engineering more accurate results will be achieved to indicate the natural distributions of fluid flow velocity, wall shear stress, and pressure.

The objective of this research is to validate the behavior of degradation rate within porous magnesium scaffolds in terms of morphological which includes weight loss after degradation by means of micro-computed tomography (µCT) based on image processing. The main contribution of this work is finding another method to determine morphology based on computer simulation. In the present study, bone scaffold specimens made of pure magnesium that was prepared with three different percentages of porosities 30%, 41%, and 55%. There were immersed and subjected to the dynamic flow rate of simulated body fluid for periods of 24, 48 and 72 hours. One sample of each specimen was scanned by µCT with a resolution of 17 µm. The cross-sections of raw data were superimposed by using MIMICS software to form a 3D reconstruction of the samples after degradation. The degradation morphology was collected from the simulation and showed good agreement with the experimental results by only less than 2%. Based on the simulation results, it is possible to give a recommendation for the alternative way in the morphological study of orthopedic applications.

Corrosion attacks are a scourge on offshore industrial structures. The hot dipping method is a common method used in protecting submerged material from corrosion attacks. The main objective of this study was to investigate the effect of variations in hot dipping time in Lead (Pb) on corrosion attack by performing corrosion rate test, weight loss measurement, microstructure analysis and fatigue test. The results revealed that the longer the hot dipping was carried out there was a decrease in the value of corrosion rate and weight loss of ASTM A36.

The main factor to support daily life is water, but the fact is there are approximately 2.1 billion people currently threatened with a shortage of clean water. Polyethersulfone (PES) and Polyvinylidene Fluoride (PVDF) are polymers that are commonly used for membrane fabrication because they have extraordinary properties in the screening process. The addition of addictive substances into the membrane formation process is no less important as supporting the ability to be even better in membranes Titanium Dioxide (TiO2) as an additive with properties relevant to the two polymers which can cover the shortcomings of the two polymers. The printing process of PVDF and PES membranes with the addition of TiO2 uses a copper plate which is flowed with an electric field of 15000V DC. The results of the surface morphology of Scanning Electron Microscopy (SEM) both showed extraordinary changes compared without modification to the printing process as in previous studies. The tensile strength test results showed uniformity with the membrane morphology and an increase in the maximum stress value of the membrane to 3.86 MPa. Surface roughness values can help identify membrane impurity properties which are also relevant to the results of water treatment performance tests and contact angles. Finally, the process of forming membranes with the additional modification of the printing process can open new avenues to maximize water treatment performance and service life on the membrane.