Authors:Syifa Ula Hamidya, Yustinus Denny Ardyanto, Indriati Paskarni Pages: 375 - 378 Abstract: Lack of involvement in interventions to carry out observations and analysis that causes the conditions and behavior of employees at one of the logistics companies at the Jakarta branch. The research aims to reduce potential unsafe of conditions & unsafe actions in the workplace environment. This process involves employees recognizing potential problems in the workplace within the procedures of observation, feedback, and employee behavior interventions. The methodology used in this study is a descriptive method to describe present or ongoing issues. This method allows for assessing a condition and program implementation to make further improvements in the future. There are still several obstacles in implementing the K3 Program (Safety, Health, and Environment), where the program is still being performed manually. BBS STAR program does not cover unsafe conditions and unsafe actions, so reporting workers to management regarding conditions at work still not optimal yet. Employees also have some difficulty reporting unsafe conditions and unsafe actions in the workplace. SEWS program can be a preventive step in the occurrence of potential danger. The quality of employees could increase with the habit of analyzing dangerous aspects of the workplace environment. Employees' involvement in the SEWS contribution program can also help establish moral consistency.Keywords: K3, Unsafe conditions and unsafe actions, SEWS Program PubDate: 2023-01-17 DOI: 10.21107/rekayasa.v15i3.18381 Issue No:Vol. 15, No. 3 (2023)
Authors:Richard Martin, Amin Setyo Laksono, Harsuko Riniwati, Setyo Widagdo Pages: 379 - 385 Abstract: The maritime dimension defense strategy model is a part of the Archipelago Marine Defense Strategy, referring to the dynamics or developments in the strategic environment and the capabilities of available national resources. In carrying out an assessment of the defense strategy of the archipelagic nation's sea dimension, it is determined by the influence and interaction of interrelationships between balancing aspects of Naval Forces and Integrated Fleet Weapons Systems (SSAT) with Threat aspects as a complex system, so an analysis is needed to get a value on the assessment defense strategy of the maritime dimension of the archipelagic state, which consists of aspects of developing the strength of the Navy and aspects of Potential Threats. So it needs to be compiled in a dynamic model that can represent a value in the assessment of the marine defense dimension of the archipelagic nation which is projected based on the time dimension up to the next 15 years. In this research, the researchers compiled a system dynamic model approach to obtain an assessment of the value of each variable and sub-variable. The results of the formulation and simulation model on the assessment of the sea dimension defense strategy, obtained values based on the following strategic scenarios: (1) Fleet In Being defense strategy at an index value of 5.72, (2) Blockade defense scenario 5.72, (3) Defense scenario Decesive Battle 5.73, (4) combined scenario between fleet in being and blockade 5.72, (5) combined scenario of fleet in being and decesive battle 5.78, (6) combination scenario of blocakde and decesive battle 5.73 and value sea defense based on current SSAT capabilities in the 15th year of 5.9, included in the alert category/quite safe. PubDate: 2023-01-17 DOI: 10.21107/rekayasa.v15i3.15465 Issue No:Vol. 15, No. 3 (2023)
Authors:Mochammad Fathurridho Hermanto, Nafisa Nandalianadhira Pages: 283 - 291 Abstract: The design of offshore platforms in Indonesia generally uses Working Stress Design (WSD) method rather than Load and Resistance Factor Design (LRFD) method. Whereas the LRFD method produces designs that better describe real conditions with load and capacity factors. The load and capacity factors are obtained from consideration of the uncertainty or randomness of their values. One of the load factors used is the environmental load factor. The environmental load factor of LRFD method is obtained based on environmental characteristics not in Indonesian waters. There are differences in the environmental characteristics of each water. Uncertainty of environmental loads in the offshore platforms design is wave height, current velocities, and wind speed. To get a structure designed according to the characteristics of the waters in Indonesia, an environmental load factor is needed in accordance with the characteristics of Indonesian water. To achieve that, structural reliability analysis is needed. Structures reliabilty represents the possibility of the structure's performance criteria being met which is expressed by the reliability index. The reliability index of structures designed using the WSD method used as a reference for LRFD method. In this study, reliability analysis was carried out using the reserve strength ratio value from the pushover analysis on WSD method. The reliability index of the structure model is 4.10. This value is categorized as high reliability. This results can be used as a reference to determine the environmental load factor of Indonesian water in the future. PubDate: 2022-12-16 DOI: 10.21107/rekayasa.v15i3.16663 Issue No:Vol. 15, No. 3 (2022)
Authors:Dudi Darmawan, Suprayogi Suprayogi, Nur Indah Muzayyanah Pages: 292 - 299 Abstract: Information on soil type and thickness becomes important in planning land use for various purposes, both agriculture and infrastructure. Measurements to identify this information have been developed using various methods, one of which is the ultrasonic wave method. However, the measurement of the thickness of the soil layer is carried out by knowing the speed of wave propagation in the layer. Generally, in various measurements, the assumption of a constant ultrasonic wave propagation speed is used. However, in various situations where the layers have mixed to form a gradation layer, it is necessary to characterize the soil first. This study aims to characterize the graded soil layer by measuring the speed of ultrasonic waves at conditioned thickness. The composition of the gradation layer was varied and the speed of propagation was measured. The results show that the composition of the soil in the gradation layer affects the ultrasonic wave propagation speed quite linearly. Experiments carried out on variations in the composition of lembang soil, laterite and humus showed a linear relationship with an average coefficient of determination of 0.978 and the results of testing the function of soil composition in the gradation layer to the speed of wave propagation resulted in an average error of 1.32%. PubDate: 2022-12-16 DOI: 10.21107/rekayasa.v15i3.16525 Issue No:Vol. 15, No. 3 (2022)
Authors:Muhammad Abdus Shomad, Andika Wisnujati, Mudjijana Mudjijana Pages: 300 - 307 Abstract: This study describes the microstructure phase and the hardness value produced in metal casting with variations in metal mold temperature with the addition of Ti-B elements. gravity casting, a technique that relies solely on gravity, is used for casting metals. This objective of this study to determine the mechanical properties characterization of specimens using die casting molds by varying the mold temperature between 250°C, 350°C, 450°C and the addition of 0.05% Ti-B alloying elements. In addition, this research can determine the right temperature for metal casting by gravity casting method. The material used in this research is recycle piston Al-Si (series 4xxx). The results of hardness testing at a temperature of 250°C have produced 123.9 HVN. The microstructure of the Al-Si-TiB alloy material has dense grain boundaries. This is because the casting with the addition of the TiB element functions as a grain refiner and reduces porosity in the microstructure. So, the smaller the porosity, the stronger the hardness of the specimen or material. This is because at low mold temperatures, the metal casting process will freeze faster, resulting in higher hardness. In addition, the increasing temperature of the die casting mold has a tendency to change the eutectic structure of silicon to primary silicon.
Authors:Rita Khathir, Sri Hartuti, Ulfa Hardiyanti Pages: 308 - 315 Abstract: The purpose of this study was to evaluate the performance of Hohenheim Aceh type solar tunnel dryer with the application of proportional integral derivative (PID) controller for outlet fans. The instrumentations used were solar tunnel dryer type Hohenheim Aceh, HTC-meter, anemometer, pyranometer, and other supporting equipments. The results showed that during the drying process solar irradiation had fluctuated, where the average solar irradiation was 649 W/m2. The average temperature in the drying chamber is 40.6°C while the average temperature in the environment is 32.9°C. Conditions in the drying chamber were suitable for drying because the temperature inside the dryer was relatively higher than the ambient temperature. The average relative humidity (RH) in the drying chamber was 36% and the average RH in the environment was about 40%. The relationship between temperature and RH value was negative and strong indicated bu r-value of 0.7379. On the other hand, the relationship between solar irradiation and temperature was positive and also strong indicating that the energy source for this dryer was from solar irradiation with an R-square of 86.02% and r-value of 0.92747. The application of PID controller had improved the performance of Hohenheim Aceh type solar tunnel dryer by preventing the incident of unproper drying temperature. However, the airflow in the drying chamber was too low thus the further engineering design is needed to improve the drying system. PubDate: 2022-12-16 DOI: 10.21107/rekayasa.v15i3.15541 Issue No:Vol. 15, No. 3 (2022)
Authors:Apang Djafar Shieddieque, Ismail Putra Nugraha, Mochammad Iqbal Zaenal Muttahar, Ghany Heryana Pages: 316 - 325 Abstract: The casting process is widely used because it has the advantage of being able to make products with small dimensions to very large dimensions, the use of materials is more efficient, the casting products can be directly used. However, in the casting process, the main triggers for the formation of defects are the nature of the mold, low permeability, low molding compressive strength, low sintering point, unsuitable sand grain distribution, so research is needed to obtain the right type of molding sand as a sand mold in metal casting. The only type of additive is bentonite. Bentonite can absorb water and expands between 8-15 times and remains dispersed in water for a certain period of time. This study aims to examine the effect of a mixture of variations of local bentonite and Australian bentonite on the characteristics of the molding sand for the sand casting process. The tests carried out are in the form of size distribution testing, X-Ray Diffraction, water content testing, compressive strength, and permeability measurements. Bentonite was varied into 5 variations of the mixture with a difference of 20% in each mixture. The results of the large size distribution of silica sand grains were 37.6 GFN. The results of XRD testing of local bentonite showed a higher content of calcium compounds and Australian bentonite contained higher sodium compounds. The largest water content test value is 5.825%. The largest compressive strength test value is 2.7 Kgf /cm2. PubDate: 2022-12-16 DOI: 10.21107/rekayasa.v15i3.16194 Issue No:Vol. 15, No. 3 (2022)
Authors:Muhammad Arif Al Aziz, Edy Prasetyo Hidayat, Ii Munadhif Pages: 326 - 332 Abstract: Around 66% of power plants in Indonesia are still sourced from coal and oil. On the other hand, Indonesia is rich in renewable energy potential but still has minimal utilization. Furthermore, the voltage at power plants that are small and less stable is also often a nuisance. Thus, an innovative hybrid, solar and hydroelectric power plant with a PID (Proportional Integral Derivative) based voltage stabilizer was created. PID-based voltage stabilizer control is generated in the form of PWM (Pulse Width Modulation). The results obtained in this study are PID control can produce the lowest voltage of 12.78 V and the highest voltage of 13.96 V with a setpoint of 13.4 V. The power generated from solar, hydro, and hybrid power plants is 11.8 Watts, 9.4 Watts, and 14.85 Watts. As for Charging the Battery, an increase of 2.72 V was obtained in 24 hours. As for the storage side, the Battery can supply a 15 watt incandescent lamp for 8 hours 55 minutes while leaving 20% of the total capacity.
Authors:Saichu Amrulloh, Humaidillah Kurniadi Wardana Pages: 333 - 339 Abstract: The use of technology in the industrial revolution era and society is growing rapidly, especially the use of robots in facilitate human work. The function of robots is not only in the industrial world, but also in the world of health, for example robots to assist in serving patients. In supporting service activities in the robotic-based health world, a medical service robot design was made which aims to help reduce the duties of medical waiters while reducing the effects of COVID-19 transmission and analyze the results of designing and monitoring systems on medical service robots. The research method used is in the form of control testing and monitoring of medical service robots from the results of non-contact body temperature sensor measurements using a design tool that was made compared to standard measuring instruments and then calculating the percentage error of the measurement, hand sanitizer sensor reading distance, and connectivity esp32 cam, esp32 dev and camera 360 with wifi as well as connection time of esp32cam, esp32dev and camera 360 with wifi. The results of the measurement of the body temperature sensor have an error presentation rate ranging from 0.002% - 0.023%, the infrared sensor distance measurement reaches 14 cm and the robot connectivity distance gets good results with a distance of 505 cm, the connectivity speed of esp32 and IP cameras depends on the wifi speed used best results in this trial at 45 ms.
Authors:Miftahul Ulum, Desmas Arifianto Patriawan Pages: 340 - 345 Abstract: Automated vehicles are increasingly being researched and developed to reduce accident rates. The braking system is an integral part of the safety factor in the vehicle. One of the development systems in braking on vehicles is the Anti-lock Braking System (ABS). ABS is a vehicle b that prevents the wheels from locking during sudden braking. The research was conducted by modelling and designing the ABS braking system using SIMULINK software on MATLAB. This research was conducted by varying the coefficient of braking friction on dry asphalt, wet asphalt, dry soil, and wet soil by paying attention to the braking distance. In the first test, the first test of the non-ABS system sets 0.9. The results were obtained with the shortest braking distance of 20 meters and the farthest, 34.5 meters. As for the results with ABS, the shortest braking distance is 17.95 meters, and the farthest is 27 meters. From the analysis that has been done, it is found that the ABS is better than the non-ABS system. This is because ABS regulates the braking calliper and is adjusted to the vehicle’s dynamics instead of statically. When there is a difference in vehicle speed with different wheels too far (while the wheels will lock), the calliper on the brakes will open and close dynamically, unlike non-ABS PubDate: 2022-12-17 DOI: 10.21107/rekayasa.v15i3.16561 Issue No:Vol. 15, No. 3 (2022)
Authors:Reni Herawati, Siti Faizah, Bingar Bimantara, Supriyanto Supriyanto Pages: 346 - 353 Abstract: Stunting is a stunted development of the brain and body of toddlers due to malnutrition since the first 1000 days of life. Stunting is a problem because toddlers grow up as the nation's successors. Fulfillment of toddler nutrition can be by consuming analog rice. The purpose of the study was to determine the best analog rice formulation from corn flour, banana peel flour and pumpkin flour and the characteristics of analog rice from physical, chemical and amino acid tests. The research method used RAL (Completely Randomized Design). The formulations of corn flour, pumpkin flour and banana peel flour were divided into 3 levels, namely the ratio (6:2:2), (6:2:1), (6:1:2). The addition of water consists of 2 levels, namely 1:1 and 1:1.5. The best analog rice was the result of sensory test followed by physical, chemical and amino acid tests. The results showed the best formulation (6:2:1) with the addition of water 1:1.5. The color test shows an average brightness of 15.56-22.239, an average redness of 5.319-8.800, an average yellowness of 28.222-29.933. Texture test obtained hardness value of 79.511 N, adhesiveness 0.119 N, Cohesiviness of 1.141 and fracturability of 2.4493 and springiness of 0.541. The value of water content is 7.21%, protein is 10.98%, carbohydrates is 73.81%, vitamin A is 67.501%, amino acids are isoleucine content is 45.60 mg/g, leucine is 118.87 mg/g, lysine is 38.91 mg/g. g, methionine 18.24 mg/g, threonine 52.00 mg/g, valine 56.16 mg/g, and phenylalanine 72.35 mg/g. PubDate: 2022-12-17 DOI: 10.21107/rekayasa.v15i3.14490 Issue No:Vol. 15, No. 3 (2022)
Authors:Khadijah Sayyidatun Nisa, Ella Melyna, Muhammad Rizky Mubarak Samida Pages: 354 - 361 Abstract: Development of bio-composite materials is growing rapidly, as these materials are light, strength, and have good resistance to corrosion. Moreover, bio-composite is one of many options to utilize agricultural waste. Polyester resin and coconut coir fiber can be utilized as matrix and filler for bio-composites. Alkalization is a method to obtain high quality cellulose from natural materials. The objective of this study is to examine the effect of KOH concentration on tensile strength and hardness of coconut coir fiber and polyester resin composite. The composite was successfully synthesized using hand lay-up method. Tensile strength and hardness tests were conducted to examine the composite’s physical properties, meanwhile Fourier Transform Infrared was employed to examine the material’s functional group. Bio-composite with coconut coir fiber and polyester ratio=40:60 yielded the highest tensile strength of 6.04 MPa. Furthermore, the composites that are synthesized with alkalization using KOH concentration of 5%wt, 10%wt, 15%wt, and no alkalization produced tensile strength 5.29, 6.92, 3.50, and 3.50 MPa respectively. In addition, the composites with KOH concentration of 5%wt, 10%wt, 15%wt, and no alkalization generated hardness 70, 73, 73, and 72 Shore D respectively. It can be concluded that the higher coconut coir fiber ratio, the higher the bio-composite’s tensile strength. PubDate: 2022-12-18 DOI: 10.21107/rekayasa.v15i3.16713 Issue No:Vol. 15, No. 3 (2022)
Authors:Evril Pramestari Febrianti, Ratih Kusuma Wardani Pages: 362 - 367 Abstract: Porang tubers contain compounds that have been widely used in health and industry, namely glucomannan. In addition, porang tubers also contain oxalate compounds that cause itching and burning when consumed directly. Porang tubers that have been cut with a size of 2x2 cm and a thickness of 0.5 cm are soaked using a solution of NaCl and distilled water. Immersion is used to reduce oxalate levels with variations in concentration, temperature and immersion time. Soaking porang tubers in either NaCl or distilled water can reduce oxalate levels. NaCl solution with a concentration of 7% has the highest % decrease in oxalate levels, which is 69.83%. NaCl solution has a better ability to reduce oxalate levels compared to distilled water. The immersion time of porang tubers with NaCl solution for 45 minutes had lower levels of oxalate than using distilled water for 60 minutes, namely 1.0809% (w/w). Porang tubers soaked in NaCl solution at a temperature of 60°C obtained a higher % decrease in oxalate levels compared to distilled water at the same temperature, which was 55.58%. PubDate: 2022-12-18 DOI: 10.21107/rekayasa.v15i3.16804 Issue No:Vol. 15, No. 3 (2022)
Authors:Andi Kurniawan, Abd. Aziz Amin, Guntur Guntur, Yogita Ayu Dwi Susanti, Adam Wiryawan, Zulkisam Pramudia, Hideki Okuda, Adi Tiya Yanuar Pages: 367 - 374 Abstract: Catfish is an aquaculture commodity that has great potential to be developed in various regions in Indonesia. The success of catfish cultivation is primarily determined by creating a suitable environment for catfish. One way to create a suitable environment for catfish cultivation is the Recirculation Aquaculture System (RAS). In applying RAS, the presence of organic matter in the pond is controlled so the pond water can be reused. The presence of organic matter in pond water is determined mainly by the activity of bacteria in the water. These bacteria are actively involved in the pond's residual organic matter degradation process. Therefore, the total number of bacteria in the water can be one of the essential parameters in the RAS. The method widely used to calculate the abundance of bacteria is counting the number of bacteria based on bacterial culture method. However, the bacteria that can be cultured are only a small part of the bacteria in the water, so the abundance value obtained does not reflect the actual bacterial population. Therefore, it is necessary to analyze the abundance of bacteria using a method closer to the actual abundance value, such as the environmental DNA (eDNA) analysis. This study aims to analyze the abundance of bacteria in water in catfish aquaculture with RAS using the eDNA method. In addition, this study also analyzes water quality data (temperature, pH, Dissolved Oxygen). This study's results indicate that the water temperature value in catfish ponds ranges from 28.0 to 29.0 °C, the average pH value is 7.7, and the dissolved oxygen is between 5.7 - 6.2 mg/L. The water quality analysis results indicate that RAS can maintain optimum conditions in the catfish cultivation process. This study also showed that the total microbial abundance value at the beginning of cultivation was 1.68 × 107 cells/ml, and on day 30, it was 3.6 × 106 cells/ml. The dynamic of bacterial densities in this study may indicate that this system can maintain the stability of the microbial community. PubDate: 2022-12-18 DOI: 10.21107/rekayasa.v15i3.16844 Issue No:Vol. 15, No. 3 (2022)
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