Recently, there has been an increase in the number of studies conducted on the process of developing hydroxyapatite (HA) to use in biocomposites. HA can be derived from natural sources such as bovine bone. The HA usage obtained from green mussel shells in biocomposites in this study will be explored. The research goal is to investigate the composition effect of biomaterials derived from polycaprolactone (PCL), polylactic acid (PLA), as well as HA obtained from green mussel shells with a chemical blending method on mechanical properties and degradation rate. First, 80 mL of chloroform solution was utilized to immerse 16 g of the PLA/PCL mixture with the ratios of 85:15 and 60:40 for 30 min. A magnetic stirrer was used to mix the solution for an additional 30 min at a temperature and speed of 50 °C and 300 rpm. Next, the hydroxyapatite (HA) was added in percentages of 5%, 10%, and 15%, as well as 20% of the PLA/PCL mixture's total weight. It was then stirred for 1 h at 100 rpm at 65 °C to produce a homogeneous mixture of HA and polymer. The biocomposite mixture was then added into a glass mold as per ASTM D790. Following this, biocomposite specimens were tested for their density, biodegradability, and three points of bending in determining the effect of HA and polymer composition on the degradation rate and mechanical properties. According to the findings of this study, increasing the HA and PLA composition yields a rise in the mechanical properties of the biocomposites. However, the biocomposite degradation rate is increasing.
This study aims to determine the design of a stove (burner) fueled by used oil, along with its specifications and to find out the test results using a stove (burner) burning used oil. Departing from the lack of utilization of used oil waste and the absence of good tools to utilize used oil. On the other hand, when used as fuel, used oil does not produce complete combustion. This study uses the French design model. This study concluded that the designed stove (burner) has a large shape compared to the burner in general. The stove (burner) reaches a pressure of 3.5 bar with a temperature of 1127 °C. The flames produced by used oil are orange. Comparison of fuel results in data that LPG is 16 minutes faster than used oil in aluminum smelting. The highest flame length is 1.57 m at a variation of 3 bar air pressure and the lowest is 0.83 m at a pressure of 1 bar. There is an influence of pressure variations on the combustion temperature with a minimum and maximum temperature reaching the highest point with a pressure of 2.5 bar with a temperature of 118 °C and 994 °C while the lowest point is at a minimum and maximum temperature at a pressure of 1 bar with a temperature of 80.4 ° C and 662 °C at 0.5 bar pressure. Fuel consumption time with a distance variation of 2200 km produces a fairly short time of 12 minutes 25 seconds. While the consumption time obtained from the variation of the distance of 1800 km is 17 minutes 11 seconds.
Abstract Pressure vessel is a container that has been used to contain a pressurized fluids, either oil, gas, or other chemical fluids. It is widely used for the oil, gas and other chemical based industries. Nowadays, finite element analysis is commonly used to reduce the high cost of testing a pressure vessel before manufacturing process. However, further validation is needed to ensure the results of the simulation and safety of the pressure vessels. In this study, theory of distortion energy is used as the tools of validation based on materials properties and behavior. And finally to ascertain wether the pressure vessel is possible for production or a refinement for safety is needed. The results of the study shown that theory of distortion energy can be used as validation tool for finite element analysis on a pressure vessels, however it cannot ensure the safety. Therefore other validation methods are needed to ascertain the safety of the pressure vessel discussed in this report. The cost analysis shown that failure theory combined with other calculation methods can save costs in pressure vessel testing, although some fairly expensive tests cannot be avoided.
Abstract Research on composites involving natural fibers is growing. Researchers are paying attention to natural fibers because they are environmentally friendly. The weak strength of natural fibers can be overcome by combining them with glass fibers. In this study, the composite specimen was made with three different lamina arrangements, noted by A as the agel fiber and G as the glass fiber. The composite material comprises six layers of fibers with three different variations (A 6 , A 2 /G 2 /A 2 , and G 2 /A 2 /G 2 ). Before manufacturing the composite, natural fibers were treated with 4% NaOH solution for 2 hours. The manufacturing process uses the hand layup method. Performance of the composite was tested by flexural and hardness tests. Composites with the glass fiber as the outer layer get the highest strength in the flexural and hardness tests, while the overall composite with agel fiber layer gets the lowest mechanical properties. The phenomenon of fiber pull-out and delamination was seen after the material was tested, this indicated a weak bond between the fiber and matrix.
Korosi adalah proses kerusakan atau penurunan kualitas logam akibat adanya reaksi bahan logam dengan lingkungannya. Korosi atmosferik sangat dipengaruhi oleh air hujan, kabut/embun akibat kelembaban relatif tinggi. Data laju korosi penting sebagai acuan pemilihan bahan konstruksi, teknik pelapisan serta untuk standar keamanan dan umur pakai. Penelitian ini bertujuan untuk mengetahui pengaruh lokasi geografis terhadap laju korosi atmosferik material di kota Semarang. Pembagian lokasi berdasar ketinggian dataran terhadap permukaan air laut. Daerah Semarang atas pada 90 – 359 m dpl, daerah Semarang tengah pada 0,75 – 3,5 m dpl, dan daerah Semarang Pesisir yang berjarak 4 – 6 km dari batas pantai. Pipa besi dan baja konstruksi sebagai spesimen uji. Spesimen diletakkan di Sembilan lokasi berbeda selama tiga bulan dengan pengambilan spesimen  tiap satu bulan. Laju korosi dihitung dengan metode kehilangan berat. Pembersihan spesimen menggunakan standar ASTM G-1. Hasil penelitian menunjukkan laju korosi atmosferik bervariasi dari 1,74 mpy sampai 7,48 mpy. Laju korosi tertinggi terjadi di lokasi G (Genuk) pada pipa besi sebesar 7,48 mpy atau 189,80 µmpy setara dengan tingkat C5 (80 – 200 µmpy) kategori korosi sangat tinggi. Semakin mendekati daerah pesisir laju korosi semakin tinggi. Kata kunci : ASTM-G1, korosi atmosferik, kota Semarang, laju korosi, weight loss
Abstract The purpose of this study is to synthesize and characterize of iron sand from the south coastal area of Purworejo, Central Java. Iron sand was mechanically filtered using permanent magnets 35 times. The filtered iron sand was characterized using x-ray diffraction (XRD) to determine the compound contained therein and his physical characteristics. The filtered iron sand was heated at temperatures of 800 ° C and 900 ° C for 5 hours in the furnace and after it was cold and followed by XRD testing. Based on the x-ray diffraction pattern, a single phase Fe 2 O 3 as a permanent magnet base can be formed after a 900 ° C heating process for 5 hours.
Rotogravure printing is a well-liked and effective printing technique in the packaging sector of a printing cylinder. In making an automatic rotogravure machine, it is necessary to design an appropriate control system. In Indonesia, semi-automatic technology is still used to make rotogravure machines, and printing speeds are often slow. For automation machines, they are still imported. Apart from that, the machine's ability to adjust its precision is also limited. The purpose of this article is to examine the control system for a 6-cylinder automatic rotogravure machine, and discuss the rotogravure machine printing process, important aspects of rotogravure machine operation, differentiation in selecting motor types for torque and speed control, as well as advantages in efficiency and precision control over the environment. The method of using a literature review is qualitative-descriptive. The main findings on rotogravure machines include five main aspects: (1) ink flow management, (2) control of the drying system, (3) register control, (4) tension and speed control, and (5) fault detection, data logging, and analysis.
The use of hydroxyapatite derived from green mussel (Perna Viridis) shell wastes for implant coating was investigated in this study. The study looked into using a flame-spraying technique to deposit this low-cost hydroxyapatite on AISI 316 L alloy. A standardized pull-off test on a coating thickness of 56–70 µm and a porous layer yielded a coating strength of 4.12 MPa. A melted hydroxyapatite layer with uniformly dispersed particles was visible in the SEM micrograph. The chemical elements C, Ca, Fe, Ni, P, and O corresponding to calcium orthophosphate and the alloy were revealed by EDX analysis of the coating layer. The α-tricalcium phosphate (α-TCP) found on the coating was confirmed by XRD Rietveld analysis. When the alloy is used as an implant, this α-TCP layer coating appears to have the potential to improve biocompatibility
Abstract The objective of this work is to investigate the influence of the utilization of dammar gum (DG), which is a biodegradable and renewable binder, on the mechanical properties of short pineapple leaf fiber (PALF) reinforced tapioca biopolymer (TBP). Samples with variable DG concentrations (10%, 20%, 30%, and 40% by weight) and a constant 30% PALF composition were created with varying TBP percentages using an internal mixing process and compression molding. The results showed that PALF‐TBP with 10% DG had the highest mechanical properties with tensile, flexural, and impact strength of 19.49 MPa, 18.53 MPa and 13.79 KJ/m 2 , respectively. Scanning electron microscopy (SEM) images prove the enhanced mechanical characteristics. In addition, Fourier transform infrared spectroscopy (FTIR) analysis showed that the DG improves the matrix and PALF interface. The results show that the utilization of DG significantly enhanced the mechanical characteristics of composites. In addition, it is anticipated that it will be able to create PALF‐TBP‐DG composites as a potential alternative for conventional polymers in various applications, especially in engineering applications such as automotive and packaging industries. Therefore, it is expected to be capable of contributing to sustainable development goals (SDGs). Highlights Recent studies show that damar gum (DG) has potential as a sustainable binder. Optimal composition is a critical factor in bio‐composite manufacturing. The mechanical properties improved the most when 10 wt% of DG was applied. DG could serve as a viable substitute for petroleum‐derived coupling agents. Bio‐composites may serve as alternative polymers for forthcoming applications.
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