The Journal of Mechanical Design Engineering (TDM) is a scientific publication managed by the Mechanical Engineering Study Program at Udayana University. This journal focuses on the field of mechanical engineering, particularly on aspects of mechanical design, structural analysis, engineering materials, as well as technological innovations and methods in mechanical engineering
Pengaruh Variasi Diameter Outlet Terhadap Tinggi Ruang Pengering Pada Kecepatan Aliran Fluida
The performance of a solar collector is significantly influenced by design parameters and operating conditions, such as the distance of the absorber plate from the base of the drying chamber, the ratio of the outlet pipe diameter to the height of the drying chamber, and the operating temperature of the absorber plate. These variations can determine the temperature distribution, airflow velocity, and heat transfer efficiency within the system. Different outlet pipe diameters and lengths change the pressure and airflow velocity, which directly impact the drying rate. Therefore, to understand how these parameters interact and contribute to the overall performance of the solar collector, a comprehensive study of the outlet-to-height ratio is required. Computational Fluid Dynamics (CFD) was chosen to analyze the heat transfer and fluid flow phenomena occurring within the solar collector in this study. CFD has proven effective in numerically evaluating the performance of thermal systems, and can provide a detailed picture of the temperature, pressure, and flow velocity distributions without the need for time-consuming and costly laboratory experiments. The outlet-to-height ratio was varied from 1/16:1 to 1/8:1. ¼:1, 1/3:1 and ½:1, while the absorber plate temperature was varied from 700C, 800C and 900C. From the simulation, it was found that the outlet diameter ratio of ½:1 with an absorber plate temperature of 900C produced the most optimum velocity of 0.07 m/s with an outlet temperature of 46oC and an outlet pressure of 0.13 Pa.
Analisis Pembakaran Droplet Minyak Jelantah Dengan Menggunakan Tempurung Kelapa Sebagai Karbon Aktif
Waste cooking oil is a by-product of repeated frying that contains harmful compounds and can cause environmental pollution if improperly discarded. One solution for managing it is to utilize it as an alternative fuel. This study aims to analyze the effect of adding activated carbon derived from coconut shells on the combustion characteristics of waste cooking oil droplets. Coconut shell-based activated carbon was chosen due to its high carbon content and porous structure, which make it effective as a natural catalyst in the combustion process. The experimental results show that the addition of coconut shell activated carbon significantly influences the combustion characteristics of waste cooking oil droplets. Increasing the activated carbon concentration increases the burning rate and shortens the ignition delay, accompanied by a decrease in the maximum combustion temperature. Furthermore, higher activated carbon content leads to smaller flame dimensions, indicating a more efficient combustion process. It can be concluded that coconut shell activated carbon enhances the combustion performance of waste cooking oil by improving oxidation efficiency and has great potential as a natural catalyst in developing environmentally friendly alternative fuels.
Kekerasan Komposit Dengan Matriks Pati Singkong Dan Chitosan Berpenguat Mikro Jelatang
This study aims to analyze the effect of adding micro nettle on the mechanical properties of cassava starch and chitosan-based composites, particularly in terms of hardness. Composites were synthesized with varying micro nettle volume fractions using the hand lay-up method, then hardness tests were conducted to evaluate changes in material properties. Hardness testing was conducted based on the ASTM D2240 standard using a Durometer (Shore D) testing device. The test results showed that the addition of micro nettle had a significant effect on increasing the hardness value of the composite. At addition variations of 1% to 3% micro nettle, there was an increase in hardness value of 11.88%, with the highest value reaching 64.89 Shore D at a composition of 85% cassava starch : 11% chitosan : 1% mekpo : 3% micro nettle. These findings indicate that micro nettle plays an important role in strengthening the mechanical properties of composites.
Studi Eksperimental Pengaruh Steam to Carbon Ratio 4:1 Terhadap Produksi Hidrogen Pada Reformer Melalui Proses Steam Methane Reforming
Fossil energy still supports activities in various sectors, but its constraints encourage exploration to find sustainable alternative energy. Hydrogen (H2) is a renewable energy that has a lot of potential with its advantages. Steam methane reforming (SMR) is a dominant H2-producing technology used on an industrial scale with two process stages, namely reformer and water gas shift (WGS). Steam to carbon ratio (S/C) is one of the important parameters in determining the H2 produced in the reformer. This study aims to determine the effect of S/C on H2 production in a reformer reactor with S/C 4:1, input gas composition of 70% methane (CH4) and 30% carbon dioxide (CO2), 30 grams of MgNi catalyst, set temperature of 500°C, and pressure of 1 atm. The results show that the 4:1 S/C is able to convert CH4 and CO2 by 70% and 17.96% respectively to produce H2, CO, and residual CO2 by 43.82%, 44.14%, and 12.04% respectively. This shows the role of S/C 4:1 which is able to better shift the reaction equilibrium towards the formation of products in the form of H2.
Ketahanan Bakar Komposit Pati Singkong Dan Chitosan Dengan Mikro Jelatang
This study aims to determine the fire resistance of composites based on cassava starch and chitosan with the addition of nettle microfibers. The volume fraction variations used consisted of (85% cassava starch : 11% chitosan : 3% nettle microfibers : 1% hardener), (85% cassava starch : 12% chitosan : 2% nettle microfibers : 1% hardener), and (85% cassava starch : 13% chitosan : 1% nettle microfibers : 1% hardener). In the fire resistance test, the longest ignition time of 28.24 seconds was achieved by the composite with a volume fraction of 85% cassava starch, 13% chitosan, 1% nettle microfibers, and 1% hardener, while the fastest ignition time of 14.53 seconds was recorded in the volume fraction of 85% cassava starch, 11% chitosan, 3% nettle microfibers, and 1% hardener.
Kekuatan Bending Pada Komposit Pati Singkong Dan Chitosan Dengan Mikro Jelatang
This study aims to examine the effect of the addition of nettle microfibers on the bending strength of cassava starch and chitosan-based composites. The composition variations used include T1 (85% cassava starch: 13% chitosan: 1% micro nettle: 1% mekpo), T2 (85% cassava starch: 12% chitosan: 2% micro nettle: 1% mekpo), and T3 (85% cassava starch: 11% chitosan: 3% micro nettle: 1% mekpo). Bending tests were carried out to obtain stress, modulus of elasticity, and strain values. The results showed that increa sing the fraction of micro nettle had a significant effect on the mechanical. In the bending test, specimen T3 produced the highest stress and elastic modulus of 21.477 MPa and 2.217 GPa, respectively, while T1 showed the lowest values of 12.713 MPa and 1.259 GPa. However, the highest strain value was obtained in T1 at 1.429%, while the lowest strain was found in T3 at 1.199%. Thus, the more nettle microfibers added, the more the flexural strength and elastic modulus increased, but the strain tended to decrease.
Profil Temperatur Pembakaran Co-firing Batubara Dengan RDF Pada Insinerator CFB
This study aims to analyze the temperature profile of coal and Refuse Derived Fuel (RDF) co-firing in a Circulating Fluidized Bed (CFB) incinerator under excess air variations of 0% (stoichiometric), 5%, 15%, and 25%. The experiments were conducted using MSW–coal briquettes with silica sand as the bed material, while combustion temperatures were measured at several reactor points using Type-K thermocouples. The results indicate that increasing excess air leads to a decrease in peak combustion temperature, reflecting reduced thermal reaction intensity due to the enhanced cooling effect of increased airflow. The temperature distribution at each variation exhibits a consistent trend, in which temperatures rise to a peak during fuel combustion and gradually decrease afterward. Overall, excess air significantly influences the temperature profile and has the potential to improve combustion quality through reduced flue gas emissions.
Analisis Pengaruh Steam to Carbon Ratio Pada Water Gas Shift Melalui Proses Steam Methane Reforming Terhadap Laju Konversi Karbon Monoksida
Fossil fuels still dominate current energy needs, but their limitations are driving a transition to renewable energy. Hydrogen is a renewable energy source that has the advantage of producing 142.35 MJ/kg of high energy and is environmentally friendly. Among the various methods of hydrogen production, steam methane reforming (SMR) is widely used on an industrial scale, involving reformer and water gas shift (WGS) reactions for hydrogen production. Several parameters that influence the WGS reaction include catalyst, temperature, and steam to carbon ratio (S/C). S/C is an important parameter in the WGS reaction because the addition of steam, as indicated by an increase in the S/C ratio on the WGS reactant side, can accelerate the rate of CO conversion and drive the reaction towards the product. This study was conducted to determine the effect of S/C on CO conversion in WGS output using an input gas composition of 70% CH4 and 30% CO2, 30 grams of FeCr catalyst, with a variation of S/C 2:1 in the WGS reactor. The results show that S/C 2:1 can accelerate the CO conversion rate from 54.45% at the reformer output to 47.04% at the WGS reactor output. This confirms the role of water vapor in promoting the conversion of CO with H2O towards product formation.
Pengaruh Daya Listrik Terhadap Produksi Hidrogen Dengan Metode Elektrolisis Air Alkali
Global dependence on fossil fuels drives the search for cleaner alternative energy sources. Hydrogen (H₂) emerges as a prime candidate due to its high energy density and versatile applications. One promising method for H₂ production is Alkaline Water Electrolysis (AWE), which offers advantages such as relatively low cost, long lifespan, and simple operating conditions. However, the efficiency of AWE remains limited due to energy losses from gas bubble formation and release. Key influencing factors in AWE include the electrolyte, electrodes, membrane, electrode spacing, and electrical power. This study aims to examine the effect of varying electrical power on the mass of H₂ produced in an electrolyzer cell with a fixed electrode spacing of 8 cm and a KOH electrolyte concentration of 7%. The applied power variations were 0.01 W, 0.07 W, 0.09 W, 0.14 W, and 0.31 W. H₂ production was analyzed using MATLAB-based image processing. The results show that increasing electrical power significantly enhances the mass of H₂ produced. The highest mass was obtained at 0.31 W, confirming the role of electric current in determining the number of H₂ molecules in accordance with Faraday’s law. These findings highlight the importance of optimizing operational parameters to improve the efficiency of AWE.
Analisis Kemurnian Hidrogen Pada Proses Steam Methane Reforming Menggunakan Pressure Swing Adsorption Dengan Tekanan Adsorpsi 80 Psi
One of the most promising clean energy alternatives to replace fossil fuels is hydrogen. Steam methane reforming (SMR) is the most common method for hydrogen production, which consists of reforming and water gas shift (WGS) reaction. Through reforming, hydrocarbons are converted into syngas, a hydrogen and carbon monoxide. Then, through WGS, carbon monoxide reacted with steam to further enhance hydrogen yield. To obtain hydrogen of higher purity, a purification stage using pressure swing adsorption (PSA) is required. Gas separation in PSA depends on the adsorption capacity of the selected adsorbent material, the operating pressure, and the adsorption time. This study evaluates the effect of adsorption pressure on hydrogen purity at the PSA outlet. Silica gel and activated alumina were used as adsorbents, with an adsorption pressure of 80 psi and an adsorption duration of 180 seconds. The results demonstrate that PSA at 80 psi improved hydrogen purity significantly, increasing from 48.66% at the WGS outlet to 62.43% at the PSA outlet. According to the results, higher operating pressure enhances the ability of adsorbents to capture impurities more effectively, thereby improving the overall efficiency of hydrogen purification.
Studi Eksperimental Pengaruh Temperatur Water Gas Shift Pada Proses Steam Methane Reforming Terhadap Laju Konversi Karbon Monoksida
This study evaluates how operating temperature in the Water Gas Shift (WGS) reactor affects CO conversion efficiency during hydrogen production via Steam Methane Reforming (SMR). The process involves Reformers, WGS, and Pressure Swing Adsorption (PSA) for purification. At a WGS reactor temperature of 380°C, CO conversion at the outlet was examined using a gas mixture of 80% CH4 and 20% CO2, a steam flow rate of 0.15 L/min, and 30 g of FE-CR catalyst. Results showed H2 and CO2 increased while CO decreased from the reformer to the WGS outlet: CO dropped from 51.37% to 35.68%, H2 rose from 44.90% to 51.84%, and CO2 increased from 3.73% to 12.49%. Higher WGS temperatures accelerate reactant conversion.
Pengaruh Fraksi Massa Terhadap Kekuatan Tarik Dan Densitas Green Composite Sari Pati Kentang / Serat Daun Nanas Dengan Perlakuan NaOH
The advancement of science and technology has increased the demand for green composite materials as environmentally friendly alternatives. This study utilized natural potato starch as the matrix, combined with 1 cm pineapple leaf fibers treated with NaOH. The mass fraction variations applied were 95% : 5%, 90% : 10%, and 85% : 15%. Specimens were fabricated using the hand lay-up method, with tensile tests conducted according to ASTM D3039 and density tests following ASTM D792- 08. The results revealed that the 15% fiber variation produced the best mechanical properties, achieving a tensile strength of 4.210 MPa, strain of 0.687%, and elastic modulus of 0.616 GPa. Meanwhile, the highest density was recorded at the 5% fiber variation with 1.293 g/cm³, and the lowest density at the 15% variation with 1.221 g/cm³.
Pengaruh Variasi Fraksi Volume Serat Dan Microcrystalline Cellulose (MCC) Terhadap Kekuatan Tarik Pada Komposit Polyester Berpenguat Serat Sisal
The development of material technology has driven innovations in natural fiber –based composites, including the use of sisal fiber (Agave sisalana) and Microcrystalline Cellulose (MCC) as alternative materials with superior mechanical properties. This study aims to determine the effect of varying sisal fiber volume fractions on the tensile strength of polyester composites with the addition of 5% MCC. Sisal fiber (Agave sisalana) serves as an eco-friendly natural reinforcement with favorable mechanical proper ties, while MCC is used as a filler to improve mechanical performance by enhancing the bond between the fiber and the polymer matrix, as well as reducing voids within the composite. Specimens were fabricated using the hand lay-up method with Yukalac 157 BQTN-EX polyester resin, 10 mm sisal fibers treated with 5% NaOH, and MCC amounting to 5% of the total volume. The sisal fiber volume fractions used were 25%, 30%, and 35%. Tensile tes ting was conducted in accordance with ASTM D3039 standards.
Studi Eksperimental Produksi Hidrogen Melalui Proses Alkaline Water Electrolysis Dengan Variasi Daya Listrik
Currently, the continuous use of fossil energy will hurt the environment. Therefore, a transition towards using new renewable energy (EBT) is needed as a more environmentally friendly long-term solution. Hydrogen has emerged as a new renewable energy source and the main source for a sustainable energy system. One commonly used hydrogen production process is alkaline water electrolysis (AWE), which can produce green hydrogen from renewable energy sources. This study aims to improve the performance of electrolysis by varying the electrical power applied. In this study, hydrogen gas was produced from distilled water using potassium hydroxide (KOH) as the electrolyte at a 5% concentration. The distance between the electrodes used was 8 cm. The electrical power used was 0.008 watts, 0.076 watts, 0.113 watts, 0.154 watts, and 0.333 watts. The electrode material used was SUS 316 stainless steel coated with titanium nitride (TIN). The type of membrane used was a composite membrane with the model T-TN-M500A. The research results show that the highest hydrogen mass, namely 2.61 kg, is at an electrical power of 0.333 watts. Increasing the electrical power supplied to the electrolysis cell can directly increase the mass of hydrogen produced.
Pemurnian Hidrogen Pada Proses Steam Methane Reforming Menggunakan Metode Pressure Swing Adsorption Pada Waktu Adsorpsi 120 Detik
Hydrogen is utilized as a fuel because it has advantages over conventional fuels, which producing high energy without causing pollution. One of the technologies used to produce hydrogen is steam methane reforming (SMR), in which methane is reacted with steam, typically using a catalyst, to make a mixture of carbon monoxide and hydrogen. The product of the SMR process is syngas, which is then fed into a Water Gas Shift (WGS) reactor, where the carbon monoxide (CO) content in the syngas is converted into carbon dioxide (CO₂) to produce hydrogen. The composition resulting from the WGS process then enters the next stage, which pressure swing adsorption (PSA). This process is carried out to obtain hydrogen with a higher level of purity. PSA has several parameters, including the number of beds, operating pressure, type of adsorbent, and the adsorption time used. This study was conducted to determine hydrogen purity with an adsorption time of 120 seconds in PSA using silica gel and activated alumina as adsorbents. The results showed an increase in hydrogen purity from 49% in the WGS stage to 67% after purification using the PSA method.
Pemurnian Hidrogen Pada Proses Steam Methane Reforming Menggunakan Metode Pressure Swing Adsorption Dengan Variasi Tekanan Adsorpsi 80 Psi
This research aims to examine hydrogen concentration through the application of the Water Gas Shift (WGS) and Pressure Swing Adsorption (PSA) methods at an adsorption pressure of 80 psi. The test results indicate that the WGS process produced a gas composition with hydrogen at 48.68%, carbon monoxide at 45.58%, and carbon dioxide at 5.74%. After undergoing the PSA process, the hydrogen concentration increased to 54.16%, while the carbon monoxide content decreased to 44.50%, and the carbon dioxide content also decreased to 1.20%. These findings indicate that PSA is more optimal in increasing hydrogen levels and reducing the amount of impurity gases, making it highly potential for application in hydrogen purification on an industrial scale.
Pengaruh Orientasi Arah Serat Terhadap Kekuatan Bending Komposit Epoxy Berpenguat Serat Sisal Yang Dicetak Dengan Metode Hand Lay Up
Composite offer advantages such as lightweight properties, corrosion resistence, durability, and affordability. One natural fiber that can be utilized in composite manufacturing is sisal fiber. Sisal fiber is commonly used as a composite reinforcement due to its excellent mechanical streght and abudant availability. This study was conducted using sisal fiber-reinforced epoxy composites with varying fiber orientations, 0º, 90º, 0º and 90º, 45º and 135º. The testing method applied included a (3) three-point bending test based on ASTM D790-03 and (Scanning Electron Microscopy) (SEM) test. Bases on the bending test results, the composite with 0º sisal fibre orientation exhabited the highest average maximum bending stress of 53.87088 Mpa. In contrast, the 90º fiber orientation configuration yielded the lowest bending stress value of 46.52351 Mpa. In terms of strain, the 0º and 90º sisal fiber orientation achieved the highest average value of 3.33%, while the lowest value of 2.86% was observed in the 90º fiber orientation. For elastic modul, the 90º fiber orientation showed the lowest value of 1.162 Gpa. .
Pengaruh Variasi Temperatur Operasi Terhadap SirkulasiPartikel Padat Pada Insinerator Circulating FluidizedMenggunakan CPFD Barracuda
The increase in solid waste due to population and industrial growth requires efficient and sustainable treatment solutions. One emerging approach is waste-to-energy technology based on RDF (Refuse Derived Fuel) combustion, with the Circulating Fluidized Bed (CFB) reactor as a preferred option due to its thermal efficiency and fuel flexibility. The advantage of the CFB system lies in the circulation of solid particles, which maintains even heat distribution and optimal combustion, although it s performance is influenced by operating temperature. Therefore, understanding the effect of temperature on particle circulation is essential for system effectiveness. This study evaluates the influence of temperature variation on particle circulation in a CFB reactor using CPFD Barracuda simulation. The simulation used 1.5 kg of RDF, 5 kg of silica sand, 14 m/s air velocity, and operating temperatures ranging from 750°C to 900°C. The observed parameters include residence time, volume fraction, and circulation mass. Results show that temperature affects circulation intensity: solid mass remained at 59% at 750°C and 800°C, increased to 60% at 850°C, and stabilized at 900°C. Particle residence time was around 10 seconds, and volume fraction increased from 0.589 to 0.6 and remained constant. These findings confirm that temperature regulation is crucial to optimizing circulation and combustion efficiency in RDF-fueled CFB systems.
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**The Effect of the Extrusion Process on the Quality of 3D Printing Filament Made from Virgin ABS Plastic**
Demand for 3D printing filament is increasing, but the high price of filament is an obstacle, especially for education and individuals. This study aims to independently produce filament made from virgin ABS using the Filatec PRO 3in1 extrusion machine with variations in puller speed to determine the effect of process parameters on filament outer diameter. Extrusion was carried out at a barrel temperature of 200°C with a constant screw speed of 10 rpm and puller speed variations of 10 rpm and 12 rpm. The measurement results show that an increase in puller speed will result in a decrease in filament outer diameter from 1.62 mm to 1.01 mm. The diameter no longer conforms to the standard tolerance of 3D printing (1.75 ± 0.05 mm). It can be concluded that the puller speed has an influence on the filament outer diameter results, and setting the extrusion process parameters is very important to produce quality filaments.
**Analysis of Dry-Bulb Temperature Drop in Counter-Flow Maisotsenko Air Cooling with Variations in Air and Water Mass Flow Rates**
Maisotsenko Cycle (M-Cycle) evaporative cooling system is an alternative cooling technology that offers high energy efficiency and environmental friendliness, as it requires no refrigerants and consumes significantly less electrical energy compared to conventional compressor-based systems. This study aims to experimentally investigate the performance of a counter-flow Maisotsenko cooling system under varying air-to-water mass flow rate ratios. The experiments were conducted using a specially designed test rig, with three variations of air mass flow rates (0.055 kg/s, 0.041 kg/s, and 0.028 kg/s) tested against three constant water mass flow rates (0.158 kg/s, 0.237 kg/s, and 0.316 kg/s). Performance parameters analyzed include wet bulb effectiveness, dew point effectiveness, cooling capacity, and energy efficiency ratios (EER and COP). The results are expected to reveal the relationship between air-to-water mass flow rate ratio and the thermal performance of the system, particularly in achieving low supply air temperatures close to the dew point with high energy efficiency. This study aims to contribute to the development of energy-saving and environmentally friendly cooling systems suitable for tropical climate applications.
Wet-Bulb Analysis on a Maisotsenko Parallel Flow Cooling System with Variations in Water Mass Flow Rate**
Air cooling systems in buildings generally use mechanical vapor compression, which is energy-intensive and has a negative impat on the environment. As an alternative, Maisotsenko cooling system (Maisotsenko Cycle) is capable of cooling air to near dew point without increasing humidity. This study aims to investigate the effect of variations in water mass flow rate on wet bulb effectiveness in a parallel-flow Maisotsenko system. The method used is an experiment involving adjusting the number of nozzles to achieve variations in water mass flow rate under constant airflow conditions. The results show wet buld effectiveness increses as the difference between the dry buld and wet buld temperatures off cool the outlet air to below the inlet wet buld temperature.
The Effect of Quenching Temperature Differences Using Oil as a Medium on the Hardness of 20Sn Bronze Alloy
Bronze is a metal mixture of copper (Cu) and white tin (Sn) that is widely used in the manufacture of traditional musical instruments such as gamelan, as it has good acoustic properties and high wearability. However, bronze's weakness lies in the potential for material deterioration due to long-term repeated use, which can affect sound quality. One option that can be used to increase the hardness of material properties, especially the hardness of bronze, is heat treatment using the quenching method. In this study, the general results of the Vickers hardness test showed that the highest increase in hardness occurred in specimens with heat treatment at 300°C using oil cooling media, with a value of 97.1 kgf/mm². On the other hand, the lowest hardness value was found in the raw material specimen, which amounted to 79.24 kgf/mm². The higher the quenching treatment temperature, the hardness tends to decrease. This can be seen at 400°C and 500°C.
Analysis of Two-Phase Flow Patterns of Hydrogen and Distilled Water in a Microchannel with Sudden Expansion
One of the challenges in realizing the development of a hydrogen-based economy is hydrogen transportation. Several studies have been conducted to improve the efficiency of hydrogen transportation, one of which is by using two-phase flow. Identifying the flow pattern is important because with a certain flow pattern will make it more efficient. The selection of the working fluid in two-phase flow greatly affects the characteristics of the flow pattern. Aquadest has high purity properties, is clear, odorless, and has no taste. These characteristics make it the right choice for applications in microfluidic systems, especially microchannels that have a high surface area to volume ratio. The presence of the sudden expansion phenomenon in the microchannel is expected to have a significant impact on the flow characteristics, including changes in pressure, velocity, and flow distribution. The purpose of this study is to analyze the two-phase flow pattern in microchannels with sudden expansion. The working fluids used in this study are hydrogen gas and distilled water. The superficial velocity is varied to obtain the flow pattern. The superficial gas velocity (jG) is varied in the range of 0.67-13.33 m/s, while the superficial liquid velocity (jL) is in the range of 0.1-1 m/s. The characteristics of the flow patterns formed were recorded using a high-speed camera and the observed flow patterns included bubbly, slug, slug-annular, and churn.
The Effect of Lead (Pb) Addition to High-Tin Bronze Alloy on Tensile Strength
High-tin bronze (CuSn), particularly those with over 17% tin (Sn), is commonly used in industries like gamelan and bell production due to its excellent acoustic properties. However, it faces challenges such as high market costs and brittleness, which can lead to cracking during forging or after use. This study examines the effect of lead (Pb) addition on the impact strength and macrostructure of high-tin bronze alloys. Pb was chosen for its lower cost compared to tin (Sn) and its ability to reduce porosity and improve the mechanical properties of other metals. Pb was added in quantities of 5%, 10%, and 15% to observe its effect on the alloy. Tensile tests were performed, followed by macrofracture analysis using a digital camera. The results revealed that Pb addition generally reduced the mechanical properties of CuSn. The alloy without Pb (0% Pb) had an average yield strength of 103.4 MPa and an ultimate tensile strength (UTS) of 118.7 MPa, showing the best performance and data consistency. With 5% Pb, strength decreased, yielding a yield strength of 73.7 MPa and UTS of 102.2 MPa. At 10% Pb, results were highly inconsistent due to possible inhomogeneity. The 15% Pb alloy showed a partial strength recovery but still fell short of the base material. All specimens exhibited brittle behavior, with no elongation or reduction in area, indicating no plastic deformation before fracture.
Effect of Smoke Velocity Variation on the Effectiveness of a Water Scrubber with Potassium Hydroxide (KOH) Solution in the Purification of NH₃ and H₂S
This study aims to develop a flue gas capture device by adding potassium hydroxide (KOH) solution into the water scrubber system to increase the effectiveness of removing pollutant gases and odors from the municipal solid waste (MSW) drying process at a temperature of 110°C. The MSW drying process produces pollutant gases such as CO, CO₂, CH₄ (odorless), and NH₃ and H₂S (odorous). Flue gas is flowed through a smoke chamber using a blower to a water scrubber that utilizes fluid turbulence to capture fly ash, NH₃, and H₂S. The scrubber uses 18 liters of water with the addition of 0.8 Mol KOH solution. The study tested variations in smoke flow speed between 15–30 m/s for 15 minutes to determine the optimal speed in gas purification. The results showed that a flow velocity of 25 m/s provided the most effective results, with a reduction in NH₃ concentration from 24.06 ppm to 1.3 ppm, and H₂S from 24.95 ppm to 9.1 ppm. This velocity resulted in a capture efficiency of 7.53%, making it the most optimal variation for the purification process.
Strength Analysis of Tablet Stand Design Using SolidWorks Software
This study aims to analyze the material strength of PET plastic bottle waste that has been processed into filaments through a pultrusion process and used as a tablet support material. The material was printed using 3D printing, then tested for tensile strength to obtain mechanical characteristics such as Elastic Modulus, Yield Strength, and Tensile Strength. These values were input into Solidworks software to analyze two tablet stand designs created to support the Samsung Tab S9 FE tablet. Static loading simulations were performed on both designs to compare structural performance based on Von Mises stress, displacement, and safety factor parameters. The analysis results show that the first design has higher structural strength, while the second design offers better mass efficiency and faster manufacturing processes, yet remains within safe usage limits based on a safety factor above 1.0.
The Effect of Glycerin Addition on the Tensile Strength and Density of Potato Starch Bioplastic.
The use of conventional plastics that are not environmentally friendly encourages the development of bioplastics based on natural materials. This study aims to determine the effect of the addition of glycerin as a plasticizer on the mechanical and physical properties of bioplastics made from potato starch. The variation in the amount of glycerin used was 1%, 2%, and 3%, then testing was carried out on the tensile strength and density of the specimen. The results showed that the increase in the amount of glycerin in general increased the density of bioplastics from 2,084 gr/cm³ to 2,406 gr/cm³, as well as tensile strength from 0.124 MPa to 0.408 MPa. The modulus of elasticity also increased significantly, from 32.12 GPa to 81.11 GPa. Meanwhile, the strain value showed a non-linear pattern, decreasing at 2% but increasing again at 3%. The conclusion of this study is that glycerin is effective as a plasticizer because it is able to increase the mechanical strength and rigidity of bioplastics, as well as modify its flexibility depending on the amount used. This research supports the development of environmentally friendly bioplastics based on renewable materials such as potato starch.
The Effect of Speed Variation and Speed Control on the Energy Consumption of a Converted Electric Motorcycle Using Fixed Belt Transmission.
Indon esia produ ces 2.4 billion tons of CO₂ p er year , with th e transportation s ector b eing a signifi cant contributor to emissions. To reduce pollution, gasoline motorcycles are being converted into electric motorcycles. This research analyzes the impact of using Fixed Belt Transmission on converted electric motorcycles. Tests were conducted on a 2006 Mio Sporty motorcycle that had been fitted with a Fixed Belt Transmission to replace the CVT. Static tests were performed at three speeds and with two speed con trol modes. The results show that speed control mode two is more energy-efficient than speed control mode one, with an energy consumption difference of 0,001 kWh at each speed. The Fixed Belt Transmission also reduced vibrations and noise compared to the previous CVT system.
The Effect of Reducing the Number of Transmission Mechanisms in Electric Motorcycle Conversion on Energy Consumption.
This study examines the effect of reducing the number of transmission mechanisms on electric motorcycles on energy consumption by using a transmission ratio of 0.8 on flat roads. In the study, conventional motorcycles (CE) have been converted to operate on batteries. With the transmission mechanism still connected to the chain then transmitted to the flywheel and transmitted to the primary sheave. Of these three mechanisms, there is a drawback, namely quite large vibrations. This study reduced the number of transmission mechanisms. This test was carried out on a flat road with a distance of 5 km and a speed of 30 km / h (kept constant), with variations in speed settings, and two variations of loads (70 kg and 140 kg) at a distance of 5 km. The results showed that the lowest power consumption was achieved with speed setting I and a load of 70 kg at 0.027 kWh / km. This study shows that reducing the number of transmission mechanisms can reduce energy consumption and improve the speed performance of electric motorcycles that are converted to increase.