Diffusion Foundations and Materials Applications Vol. 33

Abstract: In this article, the heat transfer and flow pattern characteristics are discussed in the proximity of convective boundary condition for three kinds of nanoparticles, namely gold, Platinum and magnetite with three different shapes, namely spherical, platelets, and lamina. Here water is taken as a base liquid. The thermal radiation impact is assumed into account. The partial differential equations are shifted into ordinary differential equations by applying an acceptable transformation and then exact solutions are acquired by promoting the Laplace transform technique. Solid volume fraction is fluctuated as 5%, 10%, 15%, and 20%. The variations of nanoliquid motion and heat transfer are displayed graphically as well as the numerical values of skin friction and rate of heat transfer at the plate are displayed in tabular pattern. In particular, the liquid motion as well as the heat transfer is least for lamina type nanoparticles, medium for platelet type nanoparticles, and greatest for spherical type nanoparticles. Moreover, the skin friction escalates and the rate of heat transfer declines for three types of nanoliquids in three distinct shapes with the progress of time. This report can be further utilized to authenticate the effectiveness of acquired mathematical results for another sophisticated nanoliquid problems.

Abstract: The transient dynamics of nonlinear dispersion of a polymeric pollutant ejected by an external source into a laminar flow of a Newtonian liquid flowing through a rectangular channel is investigated. The Boussinesq approximation is assumed for the density variation with pollutant concentration. The governing equations of mass and momentum conservation are coupled to the pollutant concentration equation as well as to the viscoelastic constitutive model for the polymer stresses. The Oldroyd-B viscoelastic constitutive model is employed to model the deformation and characteristics of the polymer stresses. The coupled system of nonlinear partial differential equations is solved numerically using robust and efficient semi-implicit finite difference methods (FDM). Solutions are presented in graphical form for various parameter values. The model can be a useful tool in understanding the dynamics of domestic and industrial pollution situations that may arise from improper discharge of long-chain hydrocarbon products into, say, water drainage systems. The novelty of this investigation is in the modelling of the long-chain hydrocarbon-product pollutants via appropriate viscoelastic (polymeric) constitutive equations. In general, it is observed that parameters which increase (decrease) the flow velocity correspondingly increase (respectively decrease) the wall shear stress. Similarly, it is observed that parameters which increase (decrease) the polymer concentration correspondingly increase (respectively decrease) the mass transfer rates. The wall shear stress and mass transfer are measurable quantities. In this respect, our work offers such measurements as predictive tools to detect the scale of contamination.

Abstract: A second law analysis is explored to investigate the irreversibility properties in a transient, porous channel flow of a viscous, incompressible, and non-Newtonian fluid. The non-Newtonian fluid model is of a Generalized Newtonian Fluid type with no elastic properties but with shear-thinning viscosity. Additionally, given that the flow is non-isothermal, the viscosity is therefore expectedly also assumed to be temperature dependent. The porous channel is subjected to constant suction and injection of fluid through the walls. Computational solutions for the underlying fluid dynamical equations, based on robust finite difference numerical techniques, are developed and implemented in time and space. We demonstrate the effects of the embedded fluid flow and heat transfer parameters on the fluid velocity and temperature profiles. We also explore the competing effects of heat transfer irreversibility versus fluid friction irreversibility. The major observations are that, in the flow regions where the maximum velocity obtains, heat transfer irreversibility significantly dominates over the otherwise insignificant fluid friction irreversibility. It is also observed that, in those flow regions away from the region of maximum velocity, the opposite scenario obtains, and hence fluid friction irreversibility significantly dominates over heat transfer irreversibility. Along the channel walls, fluid friction irreversibility notably dominates over heat transfer irreversibility. The possibility that certain parameter choices may lead to reverse scenario is not discounted.

Abstract: Spinal tuberculosis is one of the infectious diseases which according to the World Health Organization (WHO), is a major cause of health problems and one of the top 10 causes of death worldwide. The aim of this study was to fabricate a 3D printing scaffold with the design of truncated hexahedron, then combined with Injectable Bone Substitute (IBS) paste as a method for drug delivery in the case of spinal tuberculosis. Injectable Bone Substitute (IBS) paste was synthesized by combining some materials including hydroxyapatite, gelatin, hydroxypropyl methylcellulose (HPMC), and streptomycin. The scaffold was characterized with IBS paste through the digital microscope and the mechanical test to determine the mechanical strength of the scaffold. The results of the 3D printing scaffold showed that the scaffold has interconnectivity between pores. After being injected with IBS, it was seen that the entire surface of the scaffold pores was covered by IBS paste evenly. Scanning Electron Microscope (SEM) tests showed that the surface of the scaffold has been covered by IBS paste, and proves that the pores are still formed. Energy Dispersive X-Ray (EDX) test results showed that the IBS paste containing a hydroxyapatite component consisting of Ca, P, and O elements. Mechanical tests showed that the scaffold for all pore sizes had a compressive strength of 1.49-3.97 MPa before IBS injection and increased to 3.45-4.77 MPa after IBS injection. Then the bending test showed that the scaffold had a bending strength of 16.76-36.09 MPa and increased to around 21.57-40.36 MPa after being injected with IBS. The drug release test showed that the 3D printing scaffold could release streptomycin by 4.944%-6.547%, which has met the percentage of drug release that is able to kill tuberculosis bacteria. It can be concluded that 3D printing scaffold combined with IBS paste can be applied as a drug carrier as well as a method of healing spinal tuberculosis.

Abstract: Abstract. 3D printing is a rapidly developing technology in the medical world that has been used for pre-operative planning, prosthetic manufacturing, and training for medical education. This 3D printing is needed for medical education to make it easier for students to study anatomical structures. The advantages of 3D printing provide more detail and tactile representation of anatomical aspects of organs to address the problems of online learning and cadaveric limitations. This research aimed to develop the manufacture of 3D printed models of the human heart organ to improve understanding in learning for medical students. Making a 3D printed model of a heart organ is divisible into six parts: the aorta, right ventricle, left atrium, left ventricle, right atrium, and pulmonary artery. The 3D printing model creation procedure consisted of several steps: image acquisition, image post-processing, and 3D printing. This research used Computed Tomography Scanning (CT-Scan) images of the normal heart in Digital Imaging in Medicine (DICOM) format from Saiful Anwar Hospital, Malang. The segmentation uses the grow from seed technique with 3D Slicer software and is saved in STL format. The accuracy of the 3D printing was carried out by measuring dimensions and volume. Measurements are required to ensure the accuracy of 3D printing so that the resulting organs match the initial image data and can be used as learning media in anatomical structures by medical students.