Extraction of natural hydroxyapatite for biomedical applications—a review

Hydroxyapatite has recently played a crucial role in the sustainable development of biomedical applications. Publications related to hydroxyapatite as filler for biopolymers have exhibited an increasing trend due to the expanding research output. Based on the latest publications, the authors reviewed the research trends regarding hydroxyapatite use in biomedical applications. Analysis of the Scopus database using the keywords ‘hydroxy�apatite” and “biomedical applications” determined that 1,714 papers were produced between 2012 and 2021. The number of publications related to these keywords more than doubled between 2012 (99) and 2021 (247). The hydrothermal method, solid-state reactions, the sol-gel process, emulsion, micro-emulsion, and mostly chemical precipitation were used to produce synthetic hydroxyapatite. Meanwhile, calcination, alkaline hydrolysis, pre�cipitation, hydrothermal, and a combination of these techniques were used in producing natural hydroxyapatite. Studies in the current literature reveal that shell-based animal sources have been frequently used as hydroxy�apatite resources during investigations concerning biomedical applications, while calcination was the extraction method most often applied. Essential trace elements of fish bone, oyster shell, and eggshell were also found in hydroxyapatite powder. Abalone mussel shell and eggshell showed Ca/P ratios closer to the stoichiometric ratio due to the use of effective extraction methods such as manipulating aging time or stirring process parameters. This review should greatly assist by offering scientific insights to support all the recommended future research works, not only that associated with biomedical applications

Coding Template Of Sensorless Sun Tracking Using Azimuth-Elevation Mode

The next explosion in solar power research was in 1997 as consequence to Kyoto Protocol. This protocol outlined the effect of greenhouse emission which endangers our Earth. As the result, research in solar power field started to take its path again. This work is a part of the UTeM project to build the first CST model in South East Asia and was aimed to develop an azimuth-elevationmode-based template using MATLAB programming for the calculation of the heliostat position with respect to the heat absorber mounted at the top of the CST. This template will serve as the calculation platform to control the movement of the heliostat using a two-axis motion system so that the sun light will be redirected perfectly to the absorber all day long. Since the heliostat normal vector depends on sun position vector, both vectors were calculated by the program and were set as the output of the program. The input from the user will be the Cartesian coordinate of the heliostat and absorber by taking the absorber tower frontal surface and its base as the origin and also the date. The result will be in vector form and will change automatically according to the Sun movement. These values will be programmed in the micro controller which will control the motion system of the heliostat, which will be done by the Control Department of UTeM. The program´s functionality was proved via several verifications and its accuracy which is 0.0005 as stated and verified via comparison with analytical calculations. From the verifications, it can be seen that difference of the numerical and analytical results varied from 0.0000 to 0.0005 which validates the statement of minimum accuracy of the numerical calculated results is 5/10,000

Modeling And Simulation Of Wind Turbine For Partial Load Operation

The purpose of this research is mainly to model a wind turbine with doubly fed induction generator (DFIG) and to investigate its behavior in partial load operation using computer simulation. System behavior analysis and simulation are two particular approaches applied in this research. The wind turbine model is developed whereby the behavior of its main components is described by mathematical model and transformed in simulation model in MATLAB/Simulink. The simulation model is carried out in partial load operation at a wind speed of 9 m/s. The physical quantities including generator speed, torque and electrical power output are measured and evaluated. By using variable speed generator, a wind turbine model with optimum power generation at wind speed between 4 m/s to 13 m/s is created. This research shows that if mathematical models represent the wind turbine accurately, then the proposed model can be used to observe the dynamic behavior of wind turbine precisely, efficiently and inexpensively. The simulation result is expected to be a reference for extending the knowledge of dynamic behavior of wind turbines and optimize the performance of future large-scale wind turbine systems

Synthesis and characterisation of hydroxyapatite from Fringescale sardinella for biomedical applications

Hydroxyapatite (HAp) from fish by-product exhibits good biocompatibility and bioactivity on implants. The aim of the study is to investigate the elemental composition, crystalline phases, and functional groups of HAp synthesised from fringescale sardinella fish bones by heat decomposition method at temperature of 600, 900, and 1200 °C. The synthesised powders were characterized using fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). After calcination of the raw fish bone to 600, 900, and 1200 °C, the FTIR data showed the existence of phosphate and hydroxyl peaks in the calcined fish bones. At 900 and 1200°C, the XRD data observed shows well-defined peaks of HAp pattern. The elemental composition evaluated by EDS provides information on the calcium to phosphate formation into apatite with a Ca/P ratio of 2.80, 0.98, 1.64 and 1.79 atomic % for raw fish bones and calcined samples, respectively. It can be concluded that the fringescale sardinella fish bones show promising findings particularly on the synthesisation of HAp for biomedical application

Experimental Investigation Into Home Based Biodegradable Material As A Fertilizer Source

This project aims to investigate the functional group of hand-made Blackstrap Molasses Fertilizer using Blackstrap Molasses, Epsom Salt, and food wastes. The product was modified to enhance existing fertilizers in terms of environment, time, and cost. Several procedures were carried out started with a collection of food wastes, boiling food wastes with water until the food wastes were fully composted, cooling the food wastes and mixing with additives ingredients (Blackstrap Molasses and Epsom Salt). One type of test was used to test the fertilizer, which was the Fourier Transform Infrared Spectroscopy. The Fourier Transform Infrared Spectroscopy produced graph data that should be interpreted by referring to the spectroscopy chart. The results demonstrated that the wavenumber at peak 1, 2 and 3, which were 3238.9 cm-1, 2363 cm-1 and 1645 cm-1, in Blackstrap Molasses Fertilizer Infrared Spectrum Chart contained amines, phosphorus, and urea in the fertilizer. Amines, phosphorus, and urea are components that are important for plant growth development as these components are based on nitrogen and carbon elements. This study helps to reduce environmental pollution caused by food wastes and provide a more costeffective way of producing fertilizer using food wastes

Synthesis and characterisation of hydroxyapatite from Fringescale sardinella for biomedical applications

Hydroxyapatite (HAp) from fish by-product exhibits good biocompatibility and bioactivity on implants. The aim of the study is to investigate the elemental composition, crystalline phases, and functional groups of HAp synthesised from fringescale sardinella fish bones by heat decomposition method at temperature of 600, 900, and 1200 °C. The synthesised powders were characterized using fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). After calcination of the raw fish bone to 600, 900, and 1200 °C, the FTIR data showed the existence of phosphate and hydroxyl peaks in the calcined fish bones. At 900 and 1200°C, the XRD data observed shows well-defined peaks of HAp pattern. The elemental composition evaluated by EDS provides information on the calcium to phosphate formation into apatite with a Ca/P ratio of 2.80, 0.98, 1.64 and 1.79 atomic % for raw fish bones and calcined samples, respectively. It can be concluded that the fringescale sardinella fish bones show promising findings particularly on the synthesisation of HAp for biomedical application

Conceptual Design Approach And Ergonomics Analysis Of Fire Resistant Purpose Shield

Shield was used as protection from danger centuries ago. Until this moment, there was still no shield available for firefighting purpose in safe and rescue operation. This factor has put a limit to firefighters, causing death to many victims who were in critical and dangerous situation. In this project, conceptual design will be proposed aimed to protect firefighters against fire and heat. The project was based on the existing design of Federal Reserve Unit (FRU) shield and innovated by adding the application of resisting fire. The methodology used are customer survey to fire fighters, house of quality in defining customers' needs, morphological chart in defining concepts, Rula-analysis in measuring ergonomic score and Pugh method for selection of best design. Carbon fibre was selected as the main material for the shield because it has a very low material density of approximately 1.75 g/cm3 and very high melting point of approximately 3500 °C. In Rula-Analysis, the ergonomics final score was 3. Results show that carbon fibre is appropriate for lightweight and fireresistant shield. Ergonomics score of 3 for standing and kneeing position while holding shield is acceptable and further investigation can be recommended

Two-level factorial design of the pre-processing activities of polyamide 12 powder in selective laser sintering three-dimensional printing process

Powder exposure during selective laser sintering (SLS) three-dimensional (3D) printing process is detrimental to the health of workers in the indoor workspace and those in surrounding areas. To date, there is a paucity of studies concerning the factors involved in the SLS 3D printing process that have a significant effect on the indoor air concentrations. Hence, in this study, two-level factorial design was conducted to identify the factors that have a significant effect on the indoor air concentrations (particulate matter with a diameter less than 2.5 and 10.0 μm (PM2.5 and PM10), ultrafine particles (UFP), and total volatile organic compounds (TVOC)) during pre - processing activities of the SLS 3D printing process. The exposure during handling of polyamide 12 (PA12) was simulated in a 24-m2 SLS 3D printing chamber. The following factors were investigated: (1) Factor A (air velocity (fan speed of the split air conditioner), (2) Factor B (refresh rate (the use of recycled PA12 powder), (3) Factor C (collecting powder from the mixing machine), (4) Factor D (transferring powder to the SLS 3D printing machine), and (5) Factor E (pouring powder into the feeder chamber). The sampling methods were conducted according to the Industry Code of Practice on Indoor Air Quality, Department of Occupational Safety and Health, Malaysia. Based on the analysis of variance results, Factor B was the most significant factor that contributed to the PM2.5, PM10, UFP, and TVOC concentrations during the pre-processing activities of the SLS 3D printing process. In conclusion, proper handling and the use of an automated vacuum conveying technology for the pre-processing activities will help prevent the spreading of gaseous and aerosol particles to other areas within vicinity of the SLS 3D printing process

Modelling And Simulation Of A Wind Turbine With Doubly Fed Induction Generator In Full Load Operation

The paper focuses on modelling and simulation of a 5 MW wind turbine with doubly fed induction generator (DFIG) in full load operation. The wind turbine model is described mathematically and presented in simulation blocks. Through a computer simulation, the wind turbine behavior in full load operation is investigated. A speed controller is used to adjust the pitch angle of a rotor blade in high wind speed to limit the wind energy captured by the turbine to the nominal power value. By adjusting the pitch angle to 18.26° at wind speed 20 m/s, the wind turbine is protected from mechanical damage due to torque and power limitation. The simulation results obtained can be used as references for future optimization for the variable speed wind turbine operation

Extraction of natural hydroxyapatite for biomedical applications—a review

Hydroxyapatite has recently played a crucial role in the sustainable development of biomedical applications. Publications related to hydroxyapatite as filler for biopolymers have exhibited an increasing trend due to the expanding research output. Based on the latest publications, the authors reviewed the research trends regarding hydroxyapatite use in biomedical applications. Analysis of the Scopus database using the keywords ‘hydroxyapatite” and “biomedical applications” determined that 1,714 papers were produced between 2012 and 2021. The number of publications related to these keywords more than doubled between 2012 (99) and 2021 (247). The hydrothermal method, solid-state reactions, the sol-gel process, emulsion, micro-emulsion, and mostly chemical precipitation were used to produce synthetic hydroxyapatite. Meanwhile, calcination, alkaline hydrolysis, precipitation, hydrothermal, and a combination of these techniques were used in producing natural hydroxyapatite. Studies in the current literature reveal that shell-based animal sources have been frequently used as hydroxyapatite resources during investigations concerning biomedical applications, while calcination was the extraction method most often applied. Essential trace elements of fish bone, oyster shell, and eggshell were also found in hydroxyapatite powder. Abalone mussel shell and eggshell showed Ca/P ratios closer to the stoichiometric ratio due to the use of effective extraction methods such as manipulating aging time or stirring process parameters. This review should greatly assist by offering scientific insights to support all the recommended future research works, not only that associated with biomedical applications