EFEKTIVITAS PERAWATAN UNIT BOILER: STUDI KASUS DI PT. BEURATA SUBUR PERSADA

A boiler is a tool used to produce steam that is used for various purposes in palm oil mills. In a boiler system, the readiness and conditioning of the equipment are considered to meet the planned production targets. Maintenance, in particular on a boiler unit, is something that must be considered and essential to implement. This study aims to get an overview of the maintenance of the boiler unit at PT. Beurata Subur Persada. This research uses several methods in getting the desired results, including descriptive data collection/field interviews, from the observation and interview process with PT. Beurata Subur Persada, the planning of the maintenance process by factory conditions, is planned maintenance. Keywords: Boiler, Palm oil mills, Maintenance, Planned maintenance, PT. Beurata Subur Persada

ANALISA REKAYASA SIFAT MEKANIK BAJA AISI 4140 DENGAN VARIASI SUHU TEMPERING UNTUK MENINGKATKAN KEULETAN DAN KEKERASAN MATERIAL

Steel is a type of material that is widely used as a main material in the manufacture of various kinds of industrial and automatic machinery spare parts. Some mechanical properties of steel that are often used in design are hardness, ductility and toughness. Often in a design, we have difficulty getting steel with mechanical properties that are appropriate with the design. For this reason, engineering carried out mechanical properties engineering, to obtain steel in accordance with design calculations. AISI 4140 steel is a medium alloy steel. This steel is often used for industrial and automotive machinery parts. This research engineered the mechanical properties of the steel, namely the hardness and ductility of the material. The process is carried out by conducting steel hardening at 850 °C followed by rapid cooling with water media. After that, tempering at temperatures of 300 ᵒC, 400ᵒC and 500ᵒC by cooling together with the furnace. The result is hardness and tensile strength of the material has increased, when compared with untreated material. This method is effectively used to obtain mechanical strength values in accordance with technical planning calculations. . Keywords: Tempering, AISI 4140, Mechanical Properties Engineering

Simulasi Performa Turbin Propeller Dengan Sudut Pitch Yang Divariasikan

Propeller turbine performance can be improved by changing the turbine design parameters. One method that was developed is to vary the blade angle on the runner's blades. Analysis of the influence of blade angle on propeller turbine performance is done through numerical simulations based on computational fluid dynamics. The simulation is done with variations of propeller turbine blade angles of 180, 230, and 280 at flow rates of 0.08 m/s to 0.5 m/s. Simulation results show turbines with 250 blade angles have the best performance compared to turbine blade angles of 230 and 280. While the turbine blade angles of 230 tend to have higher performance compared to angles of 280 even though both have peak values for the corresponding power coefficient. Keywords—Propeller turbine, runner blade, pitch angle, CFD simulation

Orientation Effect on Statics and Natural Frequency of Cantilever Beam

Statics and frequency analyzes are important because the structure can support the static and dynamic loads. Most previous studies of statics and frequency did not involve the gravity load. The previous studies of gravity effect to the cantilever beam included the hanging, horizontal, and inverted positions. The gravity load direction is applied referred to the longitudinal and lateral beam directions in this study. The closer to the inverted position the smaller the natural frequency. The highest values of the maximum displacement and the maximum Von-Mises stress are happened if longitudinal position is horizontal and lateral orientation angle is 0°. The change of lateral orientation angle does not influence the natural frequency in this condition. Keywords—Cantilever beam, gravity load, natural frequency, orientation angle, statics

PERENCANAAN PEMBANGKIT LISTRIK HYBRID VAWT DAN SOLAR CELL SECARA OTOMATIS UNTUK PENERANGAN LAMPU JALAN

Road lighting is important for transportation activities, especially at night. The design of this Hybrid plant has a working principle that is utilizing wind gusts from a passing vehicle to turn the turbine blade and the heat of solar radiation that is absorbed through the solar panel with the sun tracking system. Parameter data that influence in the design of Hybrid Generations are variations in the number of turbine blades, turbine angle, wind speed, turbine drive rotor height, density of air and heat of solar radiation. The purpose of the problem in Designing Hybrid VAWT generating systems with the optimal angle of the turbine and Solar Cell automatically to be able to meet the electrical energy requirements for street lighting. The research method used in design through three stages, namely literature review, Technical Design and preparation of work tools and materials. The design results show that the optimal type u vertical wind turbine for toll road lighting with 3 blades and an optimal angle size of 90 0C, rotor diameter of 400 mm, rotor height of 1000 mm for average wind speed of 13.9 m / s. and Average solar heat of 28 0C with an average panel temperature of 55.3 0C using the Timer switch as a solar tracking system. The design of the plant, produces turbine power of 0.93 V to 1.17 V at 122 rpm to 214 rpm. And the solar panel produces a panel voltage of 19.59 V and an average voltage on the battery of 14 V. The stored electrical energy is able to light two LED lights with a power of 15 Watt and last for 12 hours / dayKeywords— Hybrid Power Generation, Optimal Angle, Timer Switch

Orientation Effect on Statics and Natural Frequency of Cantilever Beam

Statics and frequency analyzes are important because the structure can support the static and dynamic loads. Most studies about the statics and frequency are not included the gravity load. The previous studies of gravity effect to the cantilever beam included the hanging, horizontal, and inverted positions. The gravity load direction is applied referred to the longitudinal and lateral beam directions in this study. The closer to the inverted position the smaller the natural frequency. The highest values of the maximum displacement and the maximum Von-Mises stress are happened if longitudinal position is horizontal and lateral orientation angle is 0°. The change of lateral orientation angle does not influence the natural frequency in this condition. Keywords—Cantilever beam, gravity load, natural frequency, orientation angle, statics

PENINGKATAN EFISIENSI KOLEKTOR SURYA: MODIFIKASI MODEL FIN PIPA KOLEKTOR

The use of solar energy in Indonesia is classified as having high potential; it is caused by Indonesia as a country on the equator. The use of solar energy today is widely used in the electricity generation sector and some in water heating and cooling systems. Excessive use of fossil energy will result in uncontrolled air pollution in the years to come. Increasing pollution in the air increases the greenhouse effect, and it causes an increase in acidic substances in the air, distribution of CO2 emissions, and an increase in room temperature. Therefore it is necessary to use energy derived from the sun in various activities aimed at reducing the use of fossil energy and avoiding global warming caused by an increase in the intensity of solar radiation on the surface of the earth. From the results of the study, three types of straight horizontal fin have been developed that can be used in solar collectors. The use and utilization of this fin aim to improve the efficiency of the performance of the solar collector. Kata kunci: Solar Energy, Solar Collector, Intensity of solar radiation, Horizontal Straight Fin, Increased Efficiency.

ROBOT LENGAN HUMANOID SEBAGAI ALTERNATIF PEMINDAH GELAS KIMIA

Robot can help humans to do their job easier and save them from dangerous work. The work is dangerous because humans sometimes do mistakes. In the laboratory, a little carelessness can cause the transmission of various catastrophic diseases such as AIDS, hepatitis B, hepatitis C, herpes, malaria, and tuberculosis. Therefore, in this paper, we propose a humanoid robot arms as an alternative to move chemical beakers. The design of the robot is divided into 3 parts namely mechanical, hardware, and software. The mechanics consist of parts of the robot’s fingers, the robot's arm, the robot's shoulder, and the robot's base that uses plastic material with 3D print. The hardware of the robot is based on a microcontroller using Arduino Nano. The finger of the robot pulled by the micro servo that is controlled by a 4.5-inch flex sensor by utilizing the resistivity of the flex sensor. Based on the results of tests that have been carried out obtained good results, with the value of the flex sensor can change every bend not proportional to the servo angle. Based on the flex sensor feedback on the glove and robot's fingers, we know that the error in the thumb is 0.01357, on the index finger is 0.01065, on the middle finger is 0.00956, on the ring finger is 0.00893, and on the finger pinkie of 0.01193. The conclusion obtained from this study is that the humanoid robot arm can protect us from accident caused by human error in the laboratory.Keywords—Humanoid Hand Robot, Arduino, Flex Sensor

SISTEM MEKANIK DAN ELEKTRIK PADA PROTOTIPE ROBOT REHABILITASI KAKI

Stroke patients need rehabilitation to repair diseased parts of the body. Patients have limitations on therapists who have limitations and intensity to accompany the patient's rehabilitation process. The development of modern robotics technology provides solutions for independent consultations. This research has made a prototype of a rehabilitation robot with a mechanical design based on the foot rehabilitation movement reference as upper leg movement and lower leg movement. The movement is to bend and straighten the knee, and the movement of lifting and lowering the thigh. Mechanical adjustments to the movements applied make the prototype divided into several parts, namely asking the body, approving the legs and packing the actuator. The leg frame on the prototype has two free joints. The power system legs are built to complement the workings of the prototype and support the user's independent movement effort. The results of system testing that have been applied to this prototype are actuators that serve to assist users, provide user movement and provide additional power PWM motor used. Keywords— Stroke Patients, Rehabilitation Robot, Sistem Power Legs.

Rancangan Alat Potong Tahu Tradisional untuk Indutri Rumahan di Kabupaten Nagan Raya

Tofu processing by small businesses and small-medium industries in the Nagan Raya district of Aceh province still uses traditional methods, resulting in minimal daily production results, one of the obstacles in the field was found that the lack of tofu production results caused by working tools for cutting tofu still using knives one-eyed (kitchen knife), from the above, in this study, a number of model tools to cut tofu were adapted to suit the needs of the home industry, the stages of research in the study of literature, observation of tofu processing in the home industry, design of three models of tool design and analysis perunit costs and time efficiency assumptions about the performance of the tofu cutting device. Design using software produces three models of tofu cutting tools namely, models I and II with main frame stainless P = 100 cm, L = 100 and T = 5 cm, and model III stainless main frame P = 100 cm, L = 8 cm and T = 5 cm ,. Assumption of tool performance from the three design models with consideration of production costs and cutting speed, then from the results of literature studies and observations of the tofu making process traditionally selected model III which is more in line with the conditions of home industry workers in Nagan Raya district, with the specifications of the Long stainless main frame 100 cm Width 1 cm and Height 5 cm, tofu production capacity with two pieces of 256 pieces and a cutting speed of 150 seconds. Keywords— tofu cutting tools, home industry, analysis perunit costs, cutting speed