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In this work the composite made from epoxy resin as a matrix and natural fiber of Cordylineaustralis was used as reinforcement. The fiber was prepared from the process of water retting in fresh water for 1 weeks followed by drying. The final process was soaked in sea water to understand the effect of soaked in sea water to the adhesion of the fiber and matrix. The fiber was immersed in 5 hour and also 7 hours in sea water to be compared with the fiber that is was not immersed in sea water. The curing process also consist of 2 variation processes namely hand layup and vacuum pressure. The tensile test is conducted to investigate the final product of composite. It is found that the vacuum process resulting better tensile strength (34.610 MPa) in the sample of epoxy without fiber reinforcement (19.818 MPa for hand layup). In general for composite that are made with fiber without immersion in sea water, the tensile strength for the hand layup increase with addition of fiber fraction. In the other hand the tensile strength is decrease with addition of fiber fraction for vacuum process. For the fiber reinforcement, the hand layup resulting in better reinforcement comparing the vacuum process. .

Composite is a material that combines two or more materials that basically dissimilar chemical or physical properties from one another. In this research, we used Acropora coral reef waste particulate and Resin Polyester BQTN type 157 with Methyl ethyl ketone peroxide (MEKP) 1% as the hardener. The Hand Lay-Up molding technique is used in the process of making the material. The tensile and flexure test is done according to the ASTM D3090 and ASTM D790 – 03 standards. The purpose of this research is to discover the means to produce a composite enhanced by Acropora coral reef waste with polyester matrix and to learn the tensile and flexure strength from the Acropora coral reef waste particulate-enhanced polyester composites with mass fraction varieties of 10%, 20%, 30%, and 40%. The tensile test result of Acroporal coral reef waste particulate with polyester matrix yields average tensile strength at mass fraction variety of 40% with a score of 19,66 MPa, with an Modulus score of 636,75 MPa. The flexure test result of Acropora coral reef waste particulate with polyester matrix yields average flexure stress at mass fraction variety of 40% with a score of 112,56 MPa, with an average Elastic Modulus score of 3098,96 MPa.

Background: Humans' role in small industries as a source of labor is still dominant, mostly manual work. The research was conducted on manual workers in small agel fiber industries in Yogyakarta. Manual work is related to human strength and endurance. Ergonomic problems often arise in manual labor, including neck pain, back pain, and leg pain called musculoskeletal disorders. Non-ergonomic working conditions also increase the electrical activity of muscles. This study aims to reduce electrical muscle activity and musculoskeletal complaints by repairing an ergonomic workstation in the agel fiber twisting process.Methods: This research is an experimental study with 15 female subjects. The electrical activity of muscles is measured when working under conventional conditions (Period 1) and repairing an ergonomic work station (Period 2). The electrical activity of the muscles was measured using surface electromyography. Musculoskeletal complaints were measured before and after intervention with conventional conditions (Period 1) and ergonomic work station repair (Period 2). Musculoskeletal complaints were measured using the Nordic Body Map Questionnaire. The measurement data between the two periods were analyzed by using the paired samples t-test and the Wilcoxon signed-rank test.Results: The results showed a decrease in the upper trapezius muscles' electrical activity by 35.46% and the erector spinae muscles' electrical activity by 22.43%. The average of musculoskeletal complaints decreased by 23.77%, measured after working in period 1 and period 2.Conclusion: Ergonomic work station can reduce the electrical activity of the upper trapezius muscles, electrical activity of the erector spinae muscles, and musculoskeletal complaints in workers twisting the agel fiber rope.

The 2 stroke single cylinder (63 cc) engine of 750 watt electric generator is very popular in the application because providing enough amount of electricity for small house hold with compact size, light weight with reasonable price. Usually this type of electric generator is fuelled with gasoline that mixed with oil as lubricant. The cylinder volume of the engine is usually around 63 cc. This type of engine can be fuelled with biogas with addition component to mix biogas together with air and lubricant, and set the compression pressure at 10 bar. Biogas mainly contain methane (CH4), carbon dioxide (CO2), moisture (H2O), and hydrogen sulfide (H2S). The CH4 is combustible gas and can be used as a fuel for internal combustion engine. Moisture and H2S are easily removed from biogas. To remove CO2 from biogas is about difficult and costly, therefore acceptable content of CO2 in the biogas should be investigate related with the fuel consumption. This research is conducted to understand the influent of ratio CH4 and CO2 in the biogas to fuel consumption of the 2 stroke single cylinder engine of 750 watt electric generator. The variations ratio of CH4 and CO2 were obtained from anaerobic digester with batch system. The results indicate that the CH4 and CO2 ration in the range 1.667-1.967 will yield optimum efficiency that reach biogas consumption in the range of 9.1-9.8 liter/minute.

This document it is established that 2 types of biogas anaerobic digester that usually found in developing country. First type is fixed dome type of anaerobic digester and secondly is floating drum biogas anaerobic digester. Both of this type have draw back that the anaerobic process is not completed with agitation process that yield low rate of biogas production. Other serious problem is the release of slurry cannot optimal. Some of the slurry will still remain stay in the anaerobic digester especially scum. To drain and cleaning the fixed dome or floating drum biogas anaerobic digester is mandatory to be done regularly that consume time and cost. The fixed dome types as well as floating drum type are usually not portable which cause no possibility to relocate in the new site. It is the purpose of this work to introduce portable biogas anaerobic digester that suitable for developing country with volume of digester around 500 liter of slurry. The requirement of agitator is facilitated, and the anaerobic digester is possible to be operated in batch system or continuous system. The material that is used for anaerobic digester is stainless steel 304 with tungsten inert gas welding technology that is used for the manufacturing. With this design the anaerobic digester are easy to be maintenance. The batch system can keep producing biogas until 52 day with total production of biogas around 3320 liters. The continuous system was conducted by releasing for about 5 liters slurry from the outlet and after that filled with new slurry with stirring with agitator was conducted for about 10 minutes for 3 times in a day (morning, noon, and evening). The result for continuous system is a linear biogas production with rate biogas production is around 51.7 liter/day (1550 liter/30days).

The available of conventional fuels are fluctuating depend on distribution from the source production to consumer. The availability of biogas as renewable energy is increasing due to establishments of many organic wastes processing worldwide. The need of electricity to support daily life activity is a must, but the availability of electric source in remote area is limited especially for a farm that far away from commercial line distribution of electricity. This work is dedicated to solve this problem. The single cylinder 4 stroke spark ignition engine (83 cc) was designed to be able to be fuelled flexibly by using biogas or liquefied petroleum gas (LPG), or gasoline if sometime the biogas not available during initiation of the process or during maintenance of anaerobic digester. The engine is still can be run to provide electricity by using conventional fuel such as LPG or gasoline. The full consumption as well as emission of this flexible fuel engine was investigated. It is found that the fuel consumption is 9.97 L/mint for Biogas, 0.004 L/mint for gasoline and 2.24 L/mint for LPG. Surprisingly by using biogas the emission of carbon monoxide (CO) was down to almost zero (0.02 ppm), comparing gasoline 0.32 ppm, and LPG 0.4 ppm.

Biogas quality in many installation of anaerobic digester for processing organic waste are found not optimum, especially in developing country where understanding of anaerobic processing is not well known. The methane content in the biogas are usually low that make it not possible to be utilized as a fuel of the engine. Biogas Purification usually will be introduced as a solution. But this idea is about complicated for simple or small anaerobic digester. Other solution is suggested by using enrichment of biogas by using other fuel such as hydrogen or blended with city gas such as LPG gas. But for preparing hydrogen gas or commercial will also costly. This research introduces simple technique for biogas enrichment by using denatured alcohol. The biogas contents were found around 30% vol. methane (CH4) and around 2% Carbon dioxide (CO2). The price of denatured alcohol is relative cheap because the selling tax is not as much as drinking alcohol. Engine with bigger combustion (420 cc) chamber was prepared for this purpose to make possible to be fueled with biogas. The compression was set to reach 10 bar. The clearance of the both intake and exhaust valve was set in order to be possible to be running by using biogas. The biogas-air mixer was design for this purpose. The carburetor was set for use of denatured alcohol. It is found that the engine is running well by using biogas fuel that is enriched by using denatured alcohol. The emission was found better comparing using gasoline for the same engine. The fuel consumption is reported for future economic analyses.

Objective: The purpose of this research is to investigate the tensile strength of commercial synthetic non-absorbable suture made from blue polypropylene monofilament that commonly used in surgery.Methods: The commercial synthetic non-absorbable made from blue polypropylene monofilament was prepared for this purpose. The ASTM C1557-03 was used as a standard the method for analysis. For accuracy of the measurement, the diameter of the sutures was measured using optical microscope. The tensile strength, strain at failure, and modulus elasticity of the sutures were measured following instruction from the standard test method. The graph strain versus stress was provided.Results: Results show that that the average tensile strength of five valid tested samples is about 875.812 MPa. The average strain is found about 0.282. The average of modulus of elasticity is 4026.069 MPa.Conclusion: It is concluded that the sutures of commercial synthetic non-absorbable suture made from blue polypropylene monofilament having linier elastic as well as plastic properties. The average tensile strength of five valid tested samples is about 875.812 MPa. The average strain at failure is found about 0.282. The average of modulus of elasticity is 4026.069 MPa.

Alam penuh dengan contoh-contoh di mana ide bahan komposit digunakan, seperti serat alami dari tumbuhan, hewan, dan mineral. Serat alami yang digunakan sebagai penguat pada thermoset telah mendapatkan daya tarik secara komersial di bidang industri otomotif. Dalam penelitian ini memanfaatkan serat daun doyo sebagai material penguat untuk pembuatan komposit dengan matriks poliester sebagai pengikatnya. Tujuan penelitian tersebut adalah untuk mengetahui karakteristik mekanik komposit berpenguat serat daun doyo (Curculigo latifolia) dengan matrik poliester. Bahan yang digunakan adalah serat daun doyo (Curculigo latifolia), matriks poliester 157 BQTN EX dan hardener MEKPO. Serat direndam dengan NaOH 5% selama 2 jam. Komposit serat daun doyo disusun secara acak dan dicetak dengan metode hand layup. Uji tarik komposit menggunakan standar ASTM D3039 dan uji lentur menggunakan ASTM D790. Pengamatan visual digunakan untuk mengetahui mekanisme patahannya. Hasil penelitian dari komposit berpenguat serat daun doyo dengan fraksi berat serat 2,5%, 5%, 7,5% dan 10% kekuatan tarik tertinggi ada pada fraksi berat serat 10% dengan nilai kekuatan tarik rata-rata sebesar 23,389 MPa. Sedangkan kekuatan lentur tertinggi terdapat pada fraksi berat serat 0% dengan nilai 90,293 MPa.

Komposit didesain untuk menjadi material alternatif pengganti logam. Unsur utama dari komposit adalah serat dan matriks, serat adalah sumber dari kekuatan dan kekakuan pada komposit. Tujuan dilakukannya penelitian ini untuk mengetahui pengaruh fraksi berat dan waktu perendaman serat pada air laut terhadap kekuatan tarik dan kekuatan lentur dari komposit serat praksok. Pada penelitian ini digunakan serat alam yaitu serat praksok. Serat direndam pada air laut selama 0, 2, dan 4 jam. Resin yang digunakan merupakan resin epoxy dengan merek sikadur 52-id. Komposit menggunakan serat daun praksok dengan pajang 3 cm dan disusun secara acak menggunakan metode hand lay-up dengan fraksi berat serat 0%, 5%, dan 7,5%. Spesimen pengujian tarik komposit menggunakan standar ASTM D3039 dan uji lentur menggunakan ASTM D790. Hasil penelitian menunjukan kekuatan tarik dan kekuatan lentur tertinggi terjadi pada fraksi berat serat 7,5% perendaman serat 2 jam dengan nilai rata-rata kekuatan tarik sebesar 31,316 MPa dan kekuatan lentur sebesar 74,552 MPa. Pada pengamatan foto makro patahan, ikatan serat dan matriks terbaik terdapat pada variasi perendaman serat 2 jam sehingga kekuatan tarik dan lentur dapat dihasilkan secara optimum. Ikatan serat dan matriks yang baik ditandai dengan terdapatnya overload pada patahan.

The cocoon of Antheraea pernyi was grown in the laboratory with tropical artificial conditioning. The caterpillar was fed with Lantana camara leaf. They are 3 protocols provided to yield single fiber from the cocoon. The first protocol developed in this work was based on the single fiber drawing directly from the live caterpillar during cocoon stage establishment (forcibly silking). The single fiber was gently pulled and rolled up manually. The second protocol was conducted by degumming the cocoon with boiling in 5%NaoH solution. The cocoon was boiled in 5% NaOH solution and gently stirred. When the fiber was found detached from the cocoon, the boiling process was stopped, and the fiber obtained was washed with water and dried in the oven. The third protocol was simple boiling of the cocoon with water and gently stirring until the cocoon disintegrated to become a fiber. The fiber obtained was washed and dried in the oven. The first protocol by forcibly silking produced fiber with highest tensile strength of average value of 149.251 MPa. The other protocols introduced in this work resulted in lower tensile strength. Alkali treatment provided average tensile strength of 43.833 MPa and boiling in water resulted in tensile strength 52.571 MPa.

Biogas is known to contain mainly methane (CH4), and other gas impurities such as carbon dioxide (CO2), and hydrogen sulfide (H2S). Biogas should be purified to remove gas impurities prior to be used as a fuel. Activated carbon is a famous biogas purifier. Commercial activated carbons are found expensive due to high cost during production. New routes for low cost production of activated carbon are still in progress. Many natural sources were explored for production of low cost and good quality activated carbon. One of the natural sources of raw material of activated carbon is bamboo. The bamboo from species of Gigantochloa verticillata from the tropical source of Indonesia was prepared for this purpose. The bamboo was cut from the tree, dried under the sun and cut to small pieces. The dried small pieces of bamboo cut were carbonized at 700 °C for 1.5 hours in air-tight chamber made from steel. The sample then was crushed and screen in 3 different particle sizes, namely: 150-250 mesh, 250-350 mesh and 350-450 mesh. About 100 gram of carbonized bamboo from these three variations were activated at 750°C for 1 hour in around 5100 cm3 steel chamber with nitrogen gas (N2) was flowed with rate 350 ml/minute. The result of activated carbon were analyzed by using TGA (thermo gravimetric analyses) for moisture, volatile, ash and fixed carbon composition test. The activated carbon then was set in acrylic tube for biogas purification. Around 200 liters of raw biogas were collected in PVC bag. The biogas was flowed with flow rate 500 mL/minute. The biogas composition before and after passing the activated carbon was measured in three time repetitions. The results indicate that the activated carbon made from Gigantochloa verticillata bamboo developed in this work is promising biogas purifier.

Electric bicycles are one of the two-wheeled transportation that has been widely used. The structure of the bicycle is generally composed of several components, one of which is the frame. The frame serves to support the load on the bicycle. At present, many changes in design, geometry and bicycle-forming materials have been carried out. In general, bicycle frames are made of metal and alloy because they have good strength to support the load of the driver. Lately, the use of composites has begun to develop as a bicycle frame material, because the frame of the bicycle has become lighter but still has the strength to support the load. This paper presents a study of the structure of electric bicycles using composite material based on epoxy matrices with rami fiber reinforcement. This study used an experimental and simulation method by designing composite laminates with A(90o/90o/90o), B(90o/45o/90o), and C(45o/45o/45o) fiber webbing layout and then carried out free compressive strength (UCS), optical microscopy and simulation using ANSYS 19.0 software. The results obtained are composite laminate design with a woven fiber layout (45o/45o/45o) having the highest strength value with a compressive stress value σ=58.64 MPa in the axial compressive plane, and σ=1.539 MPa in the tangential compressive plane. Likewise, the simulation results also obtained the highest strength in the webbing design (45o/45o/45o) which is equal σs=58.72 MPa in the axial compressive plane and σs=1.531 MPa in the tangential compressive plane.

Activated carbon utilization in a different application requires a specific characteristic. Textural characteristics such as pore volume (V P ), surface area (S A ), pore diameter (D P ) and pore size distribution (PSDs) have an important effect on the quality and utility of activated carbon. Such characteristics are attributed to the activated carbon adsorption capacity. This research is concerned to investigate the textural properties of activated carbons derived from tabah bamboo ( Gigantochloa nigrociliata ) which are chemically activated using H 3 PO 4 activating agent. Carbonization was carried out up to 800 O C for 1.5 hours. Activations were set up to 820 O C for each 50, 100 and 150 minutes. The activated carbons produced are expressed as AC-50min, AC-100min, and AC-150min each for activation during 50, 100, and 150 minutes. The results of the research show that the higher activation time produced activated carbons with higher pore volume and wider average pore diameter but no pattern was observed on the surface area. The highest surface area of 398.400 m 2 /g and the highest pore volume of 0.680 cc/g were achieved by AC-100min and AC-150min activated carbons, respectively. The highest N 2 adsorption capacity of 48.743 cc/g was achieved on the activated carbon of AC-150min. AC-50min, AC-100min, and AC-150min have average pore diameters, respectively, around of 1.258 nm, 1.750 nm, and 3.950 nm. AC-50min and AC-100min produced pores with a monomodal pore size distribution and a bimodal pore size distribution was found on AC-150min

The engineering materials for the construction of cars, ships, planes and other are still dominated by metal materials. However, in recent years the use of metal has begun to decrease and replaced by non-metallic materials such as ceramic and composites. The advantages of ceramic and composite materials compared to metals are good mechanical properties, corrosion resistance, and lower density. Recently the use of composites tends to change from synthetic fiber composites to natural fiber composites because the composite waste of natural fibers is easily decomposed after unused. In this study, the fibers used as a reinforcement of composites were replaced by particulate of Acropora waste. The aims of this study were to obtain baseline data for further development of applied research, in particular, the mechanical properties of composites that will be used as materials for automotive components, such as door panels, dashboards, and seat backs. This study used unsaturated polyester as the matrix, methyl ethyl ketone peroxide as a hardener, with the fibers from the waste of Acropora reefs. The composites were produced by press hand lay-up techniques, with the variation of particulate grain size of 40, 100, and 200 mesh, meanwhile the particulate weight fraction was kept 30% (w/w). The results showed that maximum tensile strength about 23 MPa reached at particulate grain size 100 mesh. Maximum flexural strength around 89 MPa occurred at particulate grain size 40 mesh

Many reports related with alkali treatment on coir of coconut are available but the data related with the stress-strain curve is not provided. In this research stress-strain curve of tensile test data of the coconut single fiber obtained from alkali treatment with 5% NaOH is provided. Seven repetitions was conducted. The results indicate that the fiber is linier elastic with no indication as ductile material. The average of tensile strength is 130.9 MPa, failure (maximum) strain is 22.4 % and modulus of elasticity is 681.4 MPa. Randomly addition of 3 cm length of coconut fiber with fraction 15% in to the unsaturated polyester give maximum reinforcement that reach tensile strength of the composite about 24.5 MPa

Synthetic ropes are popular for application in marine boat as docking, anchor, tow, and sailing. The advantages of synthetic ropes are waterproof, strong and durable, can be designed for sinks or floats and able to stretches. Synthetic ropes are stronger, more resistant to rotting than ropes created from natural fibers. Synthetic ropes also possess certain disadvantages of slipperiness, and can be damaged more easily by UV light. Synthetic ropes is recognizes as a source of microplastic fiber pollutant in marine area. In this work a bark of Hibiscus tiliaceus three is introduced as candidate source of natural fiber for rope to reduce number of microplastic fiber pollutant from synthetic rope. The bark was taken from a trunk with diameter around 20 cm. The bark was immersed in water for 7 days and subsequently was soaked in 5% NaOH solution for 2 hours. Fiber obtained then was dried. It was prepared 7 valid single fiber samples. The average of tensile strength of single fiber obtained by using this method is found around 44.604 MPa. The average of Modulus elasticity E is found 365.864 MPa. The failure strain is found 11.6 %.

Pharmaceutical work activities have a high repetition level with a work attitude of standing for 8 hours potentially causing musculoskeletal complaints, which can occur despite the normal work posture. This study aims to determine musculoskeletal disorders (MSDs) and the level of MSDs based on what categories are felt, the level of complaints, the level of frequency, and the severity. The research design using the questionnaire Nordic Body Map. The study was conducted in 17 pharmacies on 54 pharmaceutical workers. The results obtained by MSDs complaints based on what categories of pain statements obtained (43.2%), cramps (16.13%), aches (53.5%). The category of complaint level obtained statement rather sick (55.9%), sick (33.5%). The category of frequency level obtained by the statement that occurs 1 to 2 times per week (56.5%), and every day (10.6%). And the severity category states that the perceived complaint is still working (49.06%) and uncomfortable (47.1%). Index Terms— Muscle Fatigue, MSDs, Nordic Body Map, Pharmacist Assistant

This research introduces method of processing zinc obtained from waste of used zinc-carbon battery to be used as biogas desulfurizer. The zinc is processed by using Natrium Chloride (NaCl) . The zinc-carbon battery consist of carbon rod as positive terminal and zinc case container as negative terminal. The electrolyte is ammonium chloride mixed with carbon powder. In the Waste of used zinc carbon battery, the zinc case is found still remind and have a potential to be used as desulfurizer. The zinc was taken out from the used battery and chopped to become small piece. About 100 gram of chopped zinc was immersed in various concentration of NaCl (25 gr/l, 50 gr/l, 75 gr/l, and 100 gr/l) at 70°C for 4 hours. The bubble of air introduce in to the solution. The zinc then was taken out from the solution, drying and compacted as a billet with diameter 5 cm and thickness about 2 cm. The billet was installed inside the pipe and 50 liter biogas with flow rate 3 liter/minute is let flown in to the desulfurizer. The Hydrogen sulfide before and after pass the desulfurizer were measured. It is found that the desulfuriser in all variation of concentration of NaCl is working well to elimination H2S to zero level.

Currently, the use of activated carbon (AC) increased significantly for the industrial sector, health, environment and agriculture. However, the commercial price of activated carbon is relatively expensive, especially for micro industries mainly due to high production costs. Additionally, it comes from non-renewable sources with limited availability. This prompted the researchers to study the production of AC from inexpensive precursors and renewable; one of which is made from bamboo. AC production can be done through a pyrolysis process followed by physical or chemical activation. Differences in raw materials and activation methods used can affect the characteristics and quality of activated carbon produced. This paper reviews the development and application of bamboo activated carbons in the life sectors and their potency for use as an adsorbent material for the absorbed natural gas (ANG).

The use of fossil fuels in motorcycles causes a rise in the concentration of emissions in the atmosphere. Adsorption using activated carbon is a method that can be applied to reduce emissions. This paper concerns the development of bamboo-activated carbons that are physically activated under different nitrogen flow rates (200, 350, and 500 cm³/min) and applied to the capture of motorcycle emissions (CO2, CO, and HC). An SEM and a Quantachrome Nova machine were applied to characterise the activated carbons. The emission of the motorcycle was measured using a Capalec multi-gas analyser. The results showed that activated carbon produced with a 350 cm³/min nitrogen flow yielded the best characteristics and the highest adsorption capability of the motorcycle emissions. With a surface area of 223.600 m²/g and a pore volume of 0.156 cm³/g, this activated carbon has adsorption efficiencies of 100%, 85.71%, and 83.41% for CO2, CO, and HC, respectively.

Activated carbons (ACs) have been manufactured from tabah bamboo (Gigantochloc nigrociliata) by carbonisation at 800°C for 1.5 hours and chemically activated. Char powdered with maximum mesh 250 µm was mixed with H3PO4 with impregnation ratio 1:1 and heated at 700°C for 1.5 hours under 100 mL/min N2 flow. ACs produced at immersion time 6, 12, and 24 hours were named AC6, AC12 and AC24, respectively. SEM observation and Pore Size Distribution exhibited that ACs produced have micropores structure. At low relative pressure, the higher the immersion time the lower micropore area and microvolume were obtained. The highest total surface area, micro surface area, and microvolume were obtained at AC6. Type IV appeared at AC24 indicating not highly micropore, indeed mesopore structure, meanwhile Type I adsorption isotherm occurred at AC6 and AC12 indicating high micropore structure. These indicate the chemical activation process can be used to wider application of activated carbon.

Construction installations built with stainless steel are the main choice of the list of materials that can be used for construction near the sea. With the recent discovery of tungsten inert gas (TIG) technology, construction with stainless steel can be realized. In some cases stainless steel welding joints are made by connecting with stainless steel of different types without regard to the strength generated especially if experiencing corrosion in this case corrosion due to sea water. In this study the tensile strength of stainless steel combination joints of type 304-201 was tested and compared with similar joints of types 304-304 and 201-201. The effect of seawater corrosion on the tensile strength of stainless steel joints was also examined. This research found that the highest tensile strength is 304-304 joints followed by 304-201 combination connections and the lowest is 201-201 joints. The effect of seawater corrosion is known to reduce the tensile strength of all types of joints.

Hot water storage tank that was made from stainless still was investigated in this case. The tank was found failure in service due to corrosion in welded section. Corrosion also was found at the bottom part of the storage tank. The tank was used for no longer than one year but unfortunately severe corrosion was found. The purpose of this research is to find the reason why the tank easily corroded especially at the bottom part and at the welding section. The research was carried out by conducting metallographic examination directly in situ by utilizing portable metallographic microscope. It is found from investigation that the corrosion was happen due to galvanic corrosion. Investigation by using X ray fluorescence also agree that the composition of the bottom part of the tank was different with the wall, and upper section. The welding filler also was found not correctly prepared that make pitting corrosion to occur. It is suggested to conduct advance research to investigate the correct composition for the filler during welding.

Biogas merupakan gas yang di hasilkan dari limbah organik yang dapat di perbaharui dan dapat di jadikan bioergi, komposisi yang terkandung dalam biogas yaitu gas hydrogen sulfida (H2S), gas karbon dioksida (CO2), oksigen (O2), H2O dan gas metana (CH4). Lamanya waktu penyimpanan biogas yaitu untuk mengetahui pengaruh komposisi biogas selama penyimpanan. Kapasitas bag yang di gunakan dalam penelitian ini berkapasitas 100 lt biogas disimpan selama 21 hari , komposisinya di uji setiap hari sampai hari ke 7 dan kembali di uji komposisinya di hari ke 21 dengan aliran biogas 3 liter per menit. Perbandingan data dalam penelitian ini biogas di simpan dalam 2 bag, bag 1 tersimpan biogas belum di murnikan , bag ke 2 tersimpan biogas yang belum di murnikan dan di tambahkan kalsium klorida (CaCl2) di dalam bag. Hasil dari penelitian ini menunjukkan peningkatan komposisi CH4 sebesar 62 % dengan penambahan CaCl2 dalam bag ke 2 dan menurunnya komposisi H2S dsan CO2 dibandingkan biogas yang tersimpan di bag 1 komposisi CH4 hanya 47 %. Biogas is a gas produced from organic waste that can be renewed and can be made into bioergy, the composition contained in biogas is hydrogen sulfide gas (H2S), carbon dioxide gas (CO2), oxygen gas (O2), H2O and methane gas (CH4). The length of time for biogas storage is to determine the effect of biogas composition during storage. The capacity of the bag used in this study with a capacity of 100 liters of biogas is stored for 21 days, the composition is tested every day until the 7th day and the composition is tested again on the 21st day with a biogas flow of 3 liters per minute. Comparison of data in this study biogas stored in 2 bags, bag 1 stored biogas not purified, bag 2 stored biogas that has not been purified and added calcium chloride (CaCl2) in the bag. The results of this study showed an increase in the composition of CH4 by 62% with the addition of CaCl2 in bag 2 and a decrease in the composition of H2S and CO2 compared to biogas stored in bag 1 in the composition of CH4 was only 47%.

Conventional anaerobic digester such as fixed dome and floating drum are found having drawback in application in developing country. It was difficult in maintenance and operation. It was also difficult to relocate to the new site of waste processing. The portable anaerobic digester is prepared in this work as a solution. The capacity is about 500 liter so that suitable for home scale organic waste treatment. The material that is used for the digester was 304 stainless steel. The digester is completed wit agitator to optimize the biogas production. A slurry of cow dung (50% cow dung+ 50% water) is use to feed the digester. There are 2 variations of slurry loading rate that were investigated in this work, namely 5 liter slurry/day and 10 liter slurry/day. The biogas production rate is found about 51.7 liter biogas/day if loading with 5 liter slurry/ day. The biogas production rate is found increase significantly to become 82 liter biogas/day if loading with 10 liter slurry/day. The quality of biogas is found better with loading rate 5 liter slurry/day which has average CH4 content about 58.75% vol. comparing the one with loading rate 10liter slurry/day that have average CH4 content about 56.40% vol.

Microfiltration polypropylene (MF-PP) membrane has been widely used in many industries due to their excellent combination of good separation performances and low production cost. In addition to membrane configuration, the structure of MF-PP membrane also plays an important role in separation performance. MF-PP membrane is commonly produced by thermal induced phase separation (TIPS) and stretching. TIPS is the simplest one where the polymer is dissolved in a solvent at a decent temperature and then cooled to induce phase separation which leads to the formation of microporous structure. However, this method is limited by the nature of PP that is difficult to dissolve in organic solvents and the solvent-contaminated effluent produced during the fabrication process. Therefore, the stretching method is more favorably used. The Stretching method involves four processing stages in sequence (i.e. melt-extrusion, annealing, stretching, and heat setting). Polymer composition, extrusion draw ratio, as well as stretching rate and temperature, are important parameters that significantly affect the pore structures evolved and thus the properties as well as the performances of MF-PP membrane. In this paper, the recent development of MF-PP fabrication by stretching methods as well as the parameters involved in each method will be reviewed and discussed comprehensively.

The carbon rod of used zinc-carbon battery was investigated in this research to be recycled as biogas desulfurizer. The carbon rod was taken out from the used battery and crushed to become a pellet with about 1 cm long. To increase its performance, the carbon rod was put in solution of KMnO4 and water then tested its performance as desulfurizer. It is found that the performance of desulfurizer increase by putting about 200 gram of carbon rod in the solution of KMnO4 with minimum concentration of 20 gram KMnO4 /liter water. It is suggested during application to use low flow rate of biogas (around 1-3 liters/minute) to achieve maximum performance.

The use of engineering materials in the construction of cars, boats and other are still dominated by metal materials. However, lately metal material has begun to decrease and replaced with non-metallic materials such as composites. The advantages of composite materials compared to metals are good mechanical properties, corrosion resistance, and lower density. The fibers that are often used as reinforcement are synthetic fibers such as glass fiber, carbon, and graphite. This synthetic fiber has advantages in mechanical properties but the price is expensive and not environmentally friendly. Recently the use of composites tends to change from synthetic fiber composites to natural fiber composites because the composite waste of natural fibers is easily decomposed after unused. The problems that are often found from composite materials is broken caused by brittle nature and low tensile strength. One technique that often used to improve the ability of composite materials is the hybridization method, which is the process of combining two or more fibers in a composite. The aims of this study were to obtain baseline data for further development of applied research, in particular, the mechanical properties of hybrid composites that will be utilized as materials for automotive components. This study used unsaturated polyester as the matrix, methyl ethyl ketone peroxide as a hardener, with the fibers derived from coral reefs and coconut fiber as reinforcement. The composites were produced with press hand lay-up techniques, with the fraction of the Acropora weight in the composite keep constant of 30%, but particulate grain size varied 40, 100, and 200 mesh, while the coconut fiber was designed with weight variations of 5%, 10%, and 15%. The results showed that hybrid composites of Acropora mesh 100 with fiber fraction 15% had the highest tensile strength of 25,35 MPa and flexural strength of about 72,04 MPa.

Open sun drying is one of the oldest techniques employed for processing agricultural products. The local practice of drying the seaweed is by spreading it over a plastic sheet on the ground and exposing it to the sun. Unfortunately, such traditional practice of drying seaweed has led to increased risk of contamination of seaweed by dust and sand particles and other impurities, as well as seaweed often suffer from lower quality. This research was conducted to examine the effect of application of table type sun drying on quality of dried seaweed, through indicators of water content, level of impurities, and brightness. The dryer was designed by using aluminum as a drying surface, with holes for circulation. The surface of aluminum is blackened to increase temperature. The results of study showed that table type sun drying reduced water content rapidly, reduce level of impurities, and improve brightness of dried seaweed.

The Gasoline fueled single cylinder generator engine are well established and available in the market with reasonable price, in the other hand the biogas fueled engine for electric generator is not well established yet in the market. The biogas energy is easy to produce therefore the price for the biogas is very much cheaper than the gasoline. The purpose of this research is to find conversion method from gasoline to biogas fuelled of the single cylinder four stroke engine of electric generator. For this purpose the biogas should be upgraded to the level of zero impurities of hydrogen sulfide H 2 S, water (H 2 O) and reducing up to zero level of CO 2 impurities. The carburetor of the gasoline engine was replaced and only component of the mixer of the fuel and air were used. The intake of the biogas fueled should be completed with valve that can be opened automatically by vacuum of the suction stroke of the engine and compression ration of the engine should be increased until reach 9:1 of compression ratio. With this conversion method, the engine of the electric generator used for this research is run well and possible to reach maximum capacity that can be achieved by using gasoline previously.

Objectives : Silk is biocompatible as biomaterial and has been used commercially as sutures. More interesting properties of the silk are that the mechanical properties exceed all natural polymer and synthetic materials. In this research, a type of silk suture is being developed from species of Attacus atlas to obtain better biocompatible sutures. A. atla s is a species of silk moth that consume not only single types of leaves. The Quality of cocoon fiber then can be arranged base on the types of the leaves that is consumed. Better biocompatibility sutures comparing with recent commercial silk sutures which is not biocompatible, can be achieved by feeding with variety types of leaves. Silk suture that already established in the market is a base product of Bombyx mori species of silk which is only consume one type of leaf (mulberry leaves). Methods: In this research, the A. atlas cocoon was produced by feeding with herb Erythrina variegate . The microstructure was observed, element composition as well as biocompatibles properties was investigated. Results: A high composition of kalium (K) as well as chloride (Cl) is identified in the fiber. The released fiber from cocoon also indicates high biocompatibility that is promising as biocompatible suture. Conclusion: The biocompatible fiber for future application as sutures is possible to be prepared by feeding the wild silkworm of A. atlas with leaf of E. variegate . The fiber is found rich with kalium (K) as well as chloride (Cl) with irregular shape of crystal at the surface of the fiber.

A biocompatible film is needed to cover an open or wide wounds. In this research, biocompatible film is created from cocoon of silkworm Bombyx mori. The sericin and fibroin proteins of the cocoon were separated. Only fibroin protein of the cocoon was used for this purpose. The fibroin was ground mechanically in water. The resulting fibroin solution was dropped onto a glass surface and heated at 60oC until solidify to become a film. The microstructure of the membrane was investigated by using optical microscope. The human osteosarcoma cell line (U2OS) was cultivated for 24 hours. It was found that the cells are able to attach and grow on the fibroin film of Bombyx mori during following 24 hours as documented by microscopic observation. This is an indication that the fibers may be used as degradable biomaterial.

Silk can be produced by spider or insect and have prospect as biomaterial for regenerative healing in medical treatment. Silk having physical and chemical properties that support biocompatibility in the living things..In this research, silk that was obtained from Indonesia natural resource of Attacus atlas silkmoth was explored and then will be developed for biocompatible biomaterial. The treatment with NaOH was developed to separate the fiber from the cocoon. The obtained fiber is investigated its mechanical property by performing tensile test for single fiber. The biocompatibility testing was conducted with human cell (osteosarccoma) cultivation. The result identify that separation by using NaOH yield better better mechanical properties comparing konvenstional method with boiling in hot water. Biocompatibility testing indicate that the the fiber having good biocompatibility.

The process of cooking oil production generally is started by grating the ripe coconut meat, then pressing the grated meat to obtain coconut milk, and finally heating the coconut milk to obtain the cooking oil. Pressing mechanism to obtain coconut milk is a very important step and decisive in the process of producing cooking oil. The amount of milk produced depends on the pressure applied at the time of pressing grated coconut. The higher the pressure, the more milk is obtained. Some commercial mechanical pressing tools that available in the market are not efficient due to the working steps too much and take long time per cycle of work. The aims of this study was to design and manufacture a power screw squeezer for the collection of coconut milk. Power screw produces a compressive force in the cylinder to push and press the grated coconut until the end of the cylinder while the coconut milk and coconut dregs flow out simultaneously. Screw press was designed using straight shaft configuration with square profile. Performance test was done to investigate the actual capacity and yield of milk produced. The results showed that squeezer of grated coconut worked well with capacity an average of 13,63 kg/h and coconut milk yield of 58%.