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This article discusses the research to determine the suitable magnetorheological (MR) damper model to produce the damping force generated by the sliding mode control (SMC) strategy. The MR damper models studied are parametric, i.e., the Bingham model, the Bouc-Wen model, and the Bouc-Wen model with a hyperbolic tangent function. The damping force of SMC usually includes sudden changes in the force and chattering. The research was carried out by calculating the value of the similarity measure of the damping force of the controller and the damping force of each model. The results show that the two Bouc Wen models had a high similarity measure. The Bouc Wen model with the hyperbolic tangent function was selected because it provides a sudden change of force and reasonable force tracking needed to develop the inverse MR damper model.

The type of hull in the catamaran is developed by following the design criteria. A catamaran has advantages over a monohull in terms of broad layout, excellent stability, and obstacles on small vessels. The catamaran design follows the semi SWATH type design by having two hulls with a small hull front corner and modeling on INCAT wave-piercing catamaran to determine the structural response to the ship, and the wave slamming process. In the simulation analysis using fluid-structure interaction with RANS and also the strength of the catamaran structure using the FE method and large base scale. In modeling also to show the hydroelastic response to the ship structure that makes the dynamic interaction between waves and ship structure more practical. Then, the design optimization of the catamaran is directed to the addition of keel fins and the application of titanium materials.

Brushless Direct Current (BLDC) motor is one type of DC motor that is commonly used for electric bicycles, electric motors, and electric cars. For the BLDC motor speed control, a driver is needed. In this research, the BLDC motor driver is designed so that the motor speed remains stable at a certain level. The motor speed will be controlled by entering the PWM (Pulse Width Modulation) value, where each PWM value produces a different speed. The driver to be designed uses the Isolated Gate Driver type with PC817 optocoupler. The test was carried out on a BLDC motor with no load conditions and load variations. The speed-accuracy from the hall sensor is 99.34%. In the no-load testing, the BLDC motor speed value is quite stable with the RMSE of 62.56. On the other side, in the load variation test, the result is varying between loads. The greater the loading value, the greater the falling speed of the motor, and the longer it will take to reach the setpoint. The load of 300gr has an RMSE of 50% higher than the RMSE of no-load.

This paper presents a new method for determining gains in a DC motor speed control system using PSO algorithm. The DC motor with a speed control system contains 2 feedback loops i.e. back emf loop and speed loop for the controller input. The controller used is the integral (I) controller and proportional-integral (PI) controller. The PSO algorithm is used to obtain the best gains for I controller and PI controller. In this paper, the PSO algorithms are PSO standard, PSO inertia and PSO constriction algorithms. The objective function is based on integral time absolute error (ITAE) criteria. The time response of DC motor with the speed controller obtained by each of PSO algorithm and the speed controller obtained by Ziegler-Nichols (ZN) method are compared. The simulation results show the transient response of the system with I and PI controllers tuned by PSO is better than the system with controller tuned by ZN method. The performance of each PSO algorithm is then qualitatively determined with a boxplot representation and hypothesis testing is performed to determine the performance of 3 pairs of PSO algorithms. The results show that the PSO-co algorithm is a better method to determine parameters of a DC motor speed controller than other PSO algorithms.

ANALISA DYNAMIC OF HANDLING KENDARAAN REVERSE TRIKE DITINJAU DARI PERGESERAN CENTRE OF GRAVITY (CG) Bhanu Putra Bumi Jurusan Teknik Mesin Fakultas Teknik Universitas Sebelas Maret Surakarta, Indonesia E-mail: bhanubumi@gmail.com Abstrak Tujuan penelitian ini adalah untuk mendapatkan perilaku dinamik handling pada kendaraan roda tiga melalui pengujian U-Turn dan perhitungan Slip Angle menggunakan metode kalkulasi quasi dinamik. Reverse Trike memiliki panjang wheelbase (L) 1,14 m, lebar Trackwidth (tf) 0,81 m, jarak suspensi roda depan (bf), dan Ground Clearance 0,11 m. Pengujian dimulai dari penimbangan kendaraan untuk mendapatkan berat rata-rata roda depan (Wf), berat roda belakang (Wr), dan berat total kendaraan (Wt). Kemudian dilakukan pengujian maneuver U-Turn dengan variasi kecepatan dari 20 km/jam sampai 50 km/jam. Analisis perhitungan dilakukan dengan mempertimbangkan Transfer Load yang terjadi pada kendaraan yang sedang melakukan maneuver. Pengereman mengakibatkan adanya momen rolling, gaya sentrifugal karena maneuver kendaraan mengakibatkan adanya momen pitching, dan percepatan kendaraan mengakibatkan adanya gaya hambat. Hasil penelitian menunjukan bahwa desain kendaraan Reverse Trike mengalami perilaku Oversteer pada saat melakukan gerak maneuver. Hal ini ditunjukan dengan nilai index understeer (Kus). Rata-rata nilai Kus pada kecepatan 20 km/jam adalah -4,33. Pada kecepatan 30 km/jam adalah -2,68. Pada kecepatan 40 km/jam adalah -2,04. Dan pada kecepatan 50 km/jam adalah -1,58. Kata Kunci: Reverse Trike, Model Handling, slip angle, transfer load, dynamic centre of gravity

The aim of this paper is to demonstrate the evaluation process to select the Aerosol Suction Machine (ASM) design to be implemented in a dental treatment practice to prevent the spread of COVID-19. There are two designs evaluated, the movable ASM and the fixed mounting ASM. The evaluation process involved four evaluation criteria: flexibility, safety level, manufacturability, and maintenance. The evaluation is conducted based on a specific requirement of a small dental clinic located in Surakarta, Indonesia. The evaluation results show that the fixed mounting is more suitable for implementing in a small dental clinic with many natural ventilation openings.

At this time the government prohibits the use of antibiotics in animal feed as a growth promoter (AGP) or antibiotic, so an effective and safe immunomodulator and herbal growth stimulant product are needed through Meniran extract products (Phyllantus niruri) and chemicals in the market are not yet optimal as immunomodulators and growth stimulants. CV. Maxipro Agrosatwa which is engaged in veterinary medicine, wholesale trade of agricultural products, and other live animals will produce feed using Meniran extract products. Extraction equipment that is needed is a Rotary vacuum evaporator. This equipment is needed to separate the solvent from the solute without high heating which will damage the solute content. The vacuum condition in the flask is to make the separation more efficient as well as accelerate the separation of the solvent from a solution by reducing the boiling point. The rotation of the flask is to increase evaporation. The complexity of this equipment is what makes CV. Maxipro Agrosatwa cannot handle it alone and requires technical assistance from the Department of Mechanical Engineering (JTM) FT UNS. Technical assistance provided by JTM FT UNS is in the form of procurement, delivery, installation, operation, and maintenance of the rotary vacuum evaporator.

This research aims to simulate and analyze the dynamics behavior of handling three-wheel reverse trike when it is turning using MATLAB. The 3-degree of freedom of vehicle model was used in this study. Equations of motion is derived based on Newton laws. The simulation of vehicle turningpath for some inputs with/without a controller is performed. The steering angle input of 10, 15, and 20 degrees and speed input of 10, 20, and 30 km/h is used. The controllerwas employed to optimize vehicle handling stability of the three-wheeled vehicle. The simulation showed that the trajectory of three-wheeled reverse trike vehicles produces a turning radius about2 meters, however the trajectory is more preserved when PID controller is used. Simulation also shown that if steering of angle 10, 15, and 20 degrees, the vehicle will corner with radius of.4, 2.6 and 4 meters respectively. Whereas with PID control, the vehicle will corner with radius maximum of 2, 4.5, and 7 meters respectively. It is concluded that the trajectory of three-wheeled vehicle increases when the speed increases. Whereas steering angle increases, the turning radius of vehiclesdecreases.

Detection of machine component failure is very important to be properly applied in a maintenance program in industries. The objective of this research is to detect gear fault using wavelet transforms. The vibration signal is acquired with accelerometer mounted at bearing houses of 2 parallel shafts with 2 spur gears (28 tooth). The gears are rotated at 1200 RPM and the spectrum is displayed. The spectrum cannot indicate gear mesh frequencies (GMF), because they are covered with frequencies such as natural and harmonic frequencies of rotating shaft. This research have developed a method to obtain GMF using wavelet decomposition and cross correlation. The results showed that with FFT applied to cross-correlation of wavelet detil components, spectrum of visible and distinctable GMF has been obtained.

The purpose of this research is to obtain a mathematical model (Full Vehicle Model) and compare the performance of passive and active suspension systems of a Three-Wheels Reverse Trike vehicle. Vehicle suspension system should able to provide good steering handling and passenger comfort. Vehicle suspension system generally only uses passive suspension components with fix spring and damper coefficients. An active suspension developed from the traditional (passive) suspension design can directly control the actuator force in the suspension system. In this paper, modeling and simulation of passive and active suspension system for a Full Vehicle Model is performed using Simulink-MATLAB software. Ziegler & Nichols tuning method is used to obtain controller parameters of Proportional Integral Derivative (PID) controller. Comparison between passive and active suspension with PID controller is conducted for disturbances input of single bump road surface profile 0.1 meters. The results are the displacement and acceleration of the vehicle body in the vertical direction of active suspension system with PID control is better in providing handling capabilities and comfort for the driver than of passive suspension system. The acceleration of 1,8G with the down time of 2.5 seconds is smaller than the acceleration of 2.5G with down time of 5.5 seconds.

This study reports the effect of sintering time on the performance of the dye-sensitized solar cells with turmeric dyes as sensitizers. Sintering TiO2 semiconductors were conducted at a temperature of 450°C for 30, 50, 90, 120, 150, and 180 minutes. The natural dye was extracted from dried turmeric powders with ethanol solvent. The results show that size of grains and the opening area of TiO2 semiconductor depended on the sintering time. The improvement of the properties of TiO2 semiconductor allowed more turmeric dyes were adsorbed by the semiconductors and then improved the performance of solar cells. The sintering time of 150 minutes produced large grains with an average diameter of 68.87 nm, and a porosity area of 26.51% caused the performance of DSSCs was the highest among other sintering time. The Voc, Jsc, and efficiency of DSSCs with turmeric-based natural dyes 0.64 V, 0.47 mA/cm2, and 0.2%, respectively.

We introduce a new cloth simulation algorithm that uses a special data of nodes-springs-elements (NSE) order that able to achieve to a realistic cloth simulation. We develop ordering procedures on data of spring-mass system that represents physics and geometrics of a cloth as in reality. In our experiments, we developed a rectangle cloth model which is initially at a horizontal position with one fixed point and it is allowed to drape by its own weight. Our simulation result is not only able to achieve a plausible cloth drapes but also reduce overstretching when large time step is used. This paper aims to demonstrate the reliability of our approach to eliminate overstretching and ability to control bending properties during simulation.

The study reports the synthesis and characterization of natural red dye. The dyes were extracted from woods of Caesalpiniasappanlinn at varied temperatures of 70, 80, 90, and 100°C for three hours. The dry wood chips and water at a ratio of 6:1 were immersed in the reactor of 150 liters. The absorbance spectra of the natural red dyes were measured by ultra-violet-visible spectroscopy. Meanwhile, Fourier transform infrared spectroscopy was used to investigate the functional groups of the natural red dyes. In addition, the basic production cost was calculated and the fastness property towards cotton fabrics was investigated according to the Indonesia national standard of 105-C06:2010, 105-B01:2010, and 0288-2008. The results showed that the functional groups found the extracted red dyes indicated the complex bond of brazilein with peak absorbance at a wavelength of 538-540 nm. The extraction temperature also changed the functional group of brazilein. From the color, the absorbance peak, the functional groups, and the main production cost, the best parameter to synthesize the natural red dyes from Caesalpiniasappanlinn was at a temperature of 80°C for two hours. Moreover, the natural red dyes has the fastness to wash resistance, light resistance, and scrub resistance by 4-5, 4, and 3-4, respectively. However, further studies for synthesis the natural red dyes by using a continuous reactor are required to identify the naturally complex compounds in brazilein for improving the fastness properties and for reducing the cost.

The most effective chassis control system for improving vehicle safety during severe braking is anti-lock braking system (ABS). Antilock effect can be gained by vibrate the pad brake at 7 to 20 cycle per second. The aim of this study is to design a new method of antilock braking system with membrane elastic vibrated by solenoid. The influence of the pressure fluctuations of brake fluid is investigated. Vibration data is collected using a small portable accelerometer-slam stick. The experiment results that the vibration of brake pad caused by controlled solenoid excitation at 10 Hz is obtained by our new method. The result of measurements can be altered by varying brake fluid pressure.

Doped and undoped zinc oxide fibers were fabricated by electrospinning at various solution flow rates of 2, 4, and 6 μl/min followed by sintering at 550 °C. The nanogenerators (NGs) fabricated from the fibers were examined for their performance by applying loads (0.25–1.5 kg) representing fingers taps on the keyboard. A higher solution flow rate resulted in a larger fiber diameter, thus reducing nanogenerator voltage. The maximum power density for undoped zinc oxide-based and doped zinc oxide-based nanogenerators was 17.6 and 51.7 nW/cm2, respectively, under a load of 1.25 kg. Enhancing nanogenerator stability is a topic that should be investigated further.

Zinc oxide fibres-based nanogenerators synthesized easily by electrospinning machine are promising to harvest electricity from mechanical energy. However, the repeatability and reproducibility were two major factors needed to be investigated to minimize product failure and to determine the feasibility of mass production of nanogenerators. The green fibres of zinc oxide were produced by electrospinning machine of zinc acetate and polyvinyl alcohol solution at a flow rate of 4 μL/min followed by sintering at temperature 550°C with heating rate 240°C/h. Each 10 nanogenerators was tested by three trained operators with three times of repetition at compressive load 0.5 kg. The nanogenerators revealed the maximum output voltage ranging from 203 to 217 mV. The value of repeatability and reproducibility of nanogenerators was approximately 24.29% showing that nanogenerators were still acceptable to be mass-produced. The relatively low reproducibility was mainly due to the operators, so that the checklist needed to be made easier and simpler for all the variables affecting to the quality of the fibres. Reducing the value of the repeatability and reproducibility is interesting to study further by creating a rotating collector so that the thickness and orientation of fibres can be arranged better.