The Ti-6Al-4V alloy is currently utilized as structural materials in artificial hip and knee joints, bone plates and screws, and artificial dental roots. It is mainly used in implants that replace hard tissue because has a high strength, good corrosion resistance, high biocompatibility compared to other conventional metallic biomaterials such as stainless steel and Co-Cr-Mo alloys. The Ti-6Al-4V alloy with low Young's modulus equivalent to that of the cortical bone is a simultaneously required in order to inhibit bone absorption. By short-time solution treatment and subsquent short-time aging, the mechanical properties of Ti-6Al-4V alloy can be improved while maintaining a low Young's modulus. The result showed optimum heat treatments were solution treatment at 930 oC (1203 K) for 60 s and subsquent aging at 530 oC (803 K) for 40 s; the yield strength and tensile strength improved without reduction in ductility. Their maximum improvement rates of reached 21,6% and 21,1%, respectively and the Young's modulus reduced with maximum rates of reached 12%.

An α+β type titanium alloy, Ti-6Al-4V, has been coated with hydroxyapatite through electrophoretic deposition (EPD) method to improve quality of the alloy surface, in order to fulfill bioactivity requirement for orthodontic application as dental roots. The deposition process was conducted by EPD at different voltages (2 volts, 5 volts, and 10 volts) and time (2 minutes and 5 minutes). After deposition, the material was heated at temperature 700 o C for 1 hour using a vacuum furnace. Coated samples analysis was conducted by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) to examine coating layer morphology and its chemical composition, respectively. Experimental results showed that the voltage and time deposition gives different effects to surface coverage and thickness of hydroxyapatite layers. Optimum layer for dental roots is obtained from the voltage of 5 volts for 5 minutes with 100% surface coverage value and 45.55μm in thickness. With low voltage and short deposition time for making a uniform coating layer, this process is much cheaper than other processes, and it is predicted to be favorable for improving osseointegration of dental roots.

The high strength of hydroxyapatite is required for biomedical applications .Silicon (Si) and Boron ( Br) are added to get a higher strength material. The mixing process HAp, Si and Br is done by ball milling. This process is followed by the compression with the pressure of 70 kg/cm2 with comparison HAp: Si,Br = 85:15, 90:10 and 95: 5. Finally the mixture is sintered at temperatures of 1000°C. The material is characterized by X-Ray Diffraction (XRD). The hardness of their sample is determined by vickers hardness test. The compressive strength is measured by compression universal test machine. The maximum hardness is obtain for composition of 85:15 that is 47,3 Vickers Hardness Number (VHN) with maximum compressive strength of 3.48 MPa . So it was concluded that Si and Br can be improve the strength of bio composite hydroxyapatite.. keyword: High Strength, Hydroxyapatite, Biokompatible, Si, Br

<p><span>Empty Fruit Bunches (EFB) are one of the palm oil industry wastes, which are quite plentiful and currently unused optimally. Biomass is one of the renewable energy resources which has important roles in the world. The bio-briquettes are manufactured through densification of waste biomass by implementing certain processes. This research aimed to obtain variations in the mold temperature at 150 ºC, 200 ºC, and 250 ºC to the calorific value and toughness of the briquette material. The toughness was tested using ASTM D 440-86 R02 standard. Arduino program was used for setting the heating resistance time of the mold, which was 20 minutes and the thermal controller was used to adjust the temperature variation. The average mold pressure was 58 Psi. The highest heating value was obtained at a mold temperature of 250 ºC with a value of 5256 cal/g, and the lowest was resulted at a temperature of 150 ºC (4117 cal/g). Meanwhile, the briquette toughness test at 200 ºC mold temperature indicated good data results in which the average loss of fiber particles was only 4.17 %, this was because the adhesion between particles by lignin and cellulose in the fiber functions optimally at this temperature so that the resistance of briquettes went through minor damage.</span></p>

Corrosion on wooden nails is very detrimental because it shortens the life of the ship. Although the used spikes have been coated with corrosion resistance material, corrosion rate is still very harmful. Therefore that additional effort is required for  reducing the corrosion rate of these spikes. Research has been done by comparing the giving of cocoa peels extract as a paint mixer to corrosion rate. As a comparison has also been done nails without paint and nails painted without additional cocoa peels extract. Calculation of corrosion rate is done by weight loss method. The addition of cocoa peels extract showed significant effect on corrosion rate, it can be explained cocoa peels containing secondary metabolite compound one of them is tannin. The tannin compound in the extract can form complex compounds with Fe (III) on the metal surface, so that the corrosion reaction rate will decreas.Keywords: cocoa peels extract, corrosion, weight loss.