Journal of Engineering and Technological Sciences
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Development of Hydro-Meteorological Hazard Early Warning System in Indonesia
Get PDFThis paper discusses the result of the development of a hydro-meteorological hazard early warning system (H-MHEWS) that combines weather prediction from Weather Research and Forecasting (WRF) and the hydrometeorological hazard index from the National Disaster Management Authority (BNPB), Indonesia. In its current development phase, the hazards that H-MHEWS predicts are floods, landslides, and extreme weather events. Potential hazard indices are obtained by using an overlay approach and resampling so that the data have a 100-m spatial resolution. All indices are classified into 4 status categories: "No alert", "Advisory", "Watch", and "Warning". Flood potential is produced by overlaying rainfall prediction at 3-hour intervals with the flood index. Landslide potential is produced by overlaying rainfall prediction with the landslide index. Extreme weather potential is divided into 3 categories, i.e. heavy rain, strong winds, and extreme ocean waves. The whole prediction is dynamic, following weather predictions at 3-hour intervals. The hazard prediction results will trigger a 'Warning' alert in case of emergency status. This alert will be set up in a notification system to make it easier for the user to identify the most dangerous hydrometeorological hazard events
Development of Drive Control Strategy for Front-and-Rear-Motor-Drive Electric Vehicle (FRMDEV)
Get PDFIn order to achieve both high-efficiency drive and low-jerk mode switch in FRMDEVs, a drive control strategy is proposed, consisting of top-layer torque distribution aimed at optimal efficiency and low-layer coordination control improving mode-switch jerk. First, with the use of the off-line particle swarm optimization algorithm (PSOA), the optimal switching boundary between single-motor-drive mode (SMDM) and dual-motor drive mode (DMDM) was modelled and a real-time torque distribution model based on the radial basis function (RBF) was created to achieve the optimal torque distribution. Then, referring to the dynamic characteristics of mode switch tested on a dual-motor test bench, a torque coordination strategy by controlling the variation rate of the torque distribution coefficient during the mode-switch process was developed. Finally, based on a hardware-in-loop (HIL) test platform and an FRMDEV, the proposed drive control strategy was verified. The test results show that both drive economy and comfort were improved significantly by the use of the developed drive control strategy
Isolation and Screening of Diesel Degrading Bacteria from Ship Dismantling Facility at Tanjungjati, Madura, Indonesia
Get PDFThe ship dismantling industry is a cause of contamination of the environment by diesel. The objectives of this study were to isolate and screen diesel degrading bacteria from diesel contaminated areas. Diesel contaminated seawater and soil samples were collected from a ship dismantling facility at Tanjungjati, Madura, Indonesia. Isolation was conducted with an aseptic technique and growing the mixture culture was carried out based on the pour plate method. After 24 h of incubation, thirteen bacteria strains were isolated from diesel contaminated seawater and soil samples from the area of study. The isolated bacteria were identified based on morphological characterization. Mostly gram positive bacteria were found. The isolated bacteria were screened by using nutrient agar medium containing various diesel concentrations (0%, 5%, 10%, and 15% (v/v)). The result of the screening test showed that the bacteria coded EL and CT displayed the best resistance and highest growth in diesel polluted medium. It was shown that both of them potentially have a higher capability of utilizing diesel as carbon and energy source than the others
Solar Radiation Forecast Using Cloud Velocity for Photovoltaic Systems
Get PDFToday, solar energy is used in a many different ways. One of the most popular technological developments for this purpose is photovoltaic conversion to electricity. However, power fluctuations due to the variability of solar energy are one of the challenges faced by the implementation of photovoltaic systems. To overcome this problem, forecasting solar radiation data several minutes in advance is needed. In this research, a methodology to forecast solar radiation using cloud velocity and cloud moving angle is proposed. Generally, a red-to-blue ratio (RBR) color model and correlation analysis are used for obtaining the cloud velocity and moving angle. Artificial neural network (ANN) forecast models with different input combinations are established. This methodology requires lower computational time since it only uses part of the pixels in the sky image. Based on R-squared analysis, it can be concluded that the ANN model with inputs of cloud velocity and moving angle and average solar radiation showed the highest accuracy among other combinations of inputs. The R-squared value was 0.59 with only a relatively small sample size of 42. The proposed model showed a highest improvement of 75.79% when compared to the ANN model based on historical solar radiation data only
An Adaptive Skin Detection Approach of Face Images with Unequal Luminance, Color Excursion, and Background Interference
Get PDFFace detection and recognition are affected greatly by unequal luminance, color excursion and background interference. For improving skin detection rates of color face images in the presence of unequal luminance, color excursion and background interference, this paper proposes an approach for automatic skin detection. This approach globally corrects the color excursion using the X, Y, Z color components. Then it establishes a self-adaptive nonlinear amendment function using the a', b'and L' components, and locally corrects the R, G, B color components of row-column transformed sub-block images to balance the global luminance and color. Finally, it constructs an L'a'b'three-dimensional semi-supervised dual-probability skin model, based on which automatic skin detection can be realized. The experimental results demonstrated that this approach has great adaptability, a high detection rate and speed
A Hybrid Multi-Criteria Analysis Model for Solving the Facility LocationâAllocation Problem: A Case Study of Infectious Waste Disposal
Get PDFChoosing locations for infectious waste disposal (IWD) is one of the most significant issues in hazardous waste management due to the risk imposed on the environment and human life. This risk can be the result of an undesirable location of IWD facilities. In this study a hybrid multi-criteria analysis (Hybrid MCA) model for solving the facility locationâallocation (FLA) problem for IWD was developed by combining two objectives: total cost minimization and weight maximization. Based on an actual case of forty-seven hospitals and three candidate municipalities in the northeastern region of Thailand, first, the Fuzzy AHP and Fuzzy TOPSIS techniques were integrated to determine the closeness of the coefficient weights of each candidate municipality. After that, these weights were converted to weighting factors and then these factors were taken into the objective function of the FLA model. The results showed that the Hybrid MCA model can help decision makers to locate disposal centers, hospitals and incinerator size simultaneously. Besides that the model can be extended by incorporating additional selection criteria/objectives. Therefore, it is believed that it can also be useful for addressing other complex problems
Settlement Evaluation of a Concrete Face Rock-Fill Dam (CFRD) Using a Back-Analysis Method Based on Measurement Results (A Case Study of Siah-Bisheh Dam)
Get PDFThe behavior of the Siah-Bisheh concrete face rock-fill dam in Mazandaran, Iran was investigated. Numerical analyses were performed before construction to evaluate the stability and predict the deformation of the dam. The material properties were chosen based on the results of geotechnical investigations. The amounts for deformation and settlement of the concrete surface were also calculated with the numerical model. The information from a number of geotechnical instruments was collected after construction and analyzed to measure settlement at different sections of the dam. The locations of the different deformations and their values are presented with various contours. The data were analyzed and used to revise the original numerical model of the dam. Following that, the long-term stability of the dam was evaluated, using parameters that were modified based on the measurement data. A comparison of the results from the numerical analysis and the values obtained from the dam settlement measurement showed that the initial results from the numerical model were much higher than the real values. It also showed that the number of construction layers used in the modeling of the dam had a significant effect on the obtained maximum amount of deformation
The Sensitivity of Aerodynamic Forces to Multi-parameters in a Bird-like Flapping Wing
Get PDFThe sensitivity of aerodynamic forces in a bird-like flapping wing was numerically studied by analyzing the aerodynamic force states under different parameters. First, the physical model and the kinematic model of the bird-like flapping wing were separately established. Then the aerodynamic force model was established and some important parameters were analyzed by adopting the Taguchi orthogonal method. Finally, a simulation was carried out, from which the order of the parameters was separately determined according to the parameters' effect on lift or thrust. The results showed that increasing the flapping frequency is one of the most important ways to increase lift and thrust. The lift can be increased by increasing the flight velocity, while the thrust can be increased by increasing the maximum flapping angle. The lift or the thrust becomes larger when the incidence angle is approximately or
Evaluation of Metro Kapsul Performance in Steady State Curving, Traction, and Braking
Get PDFTransportation is an important life aspect to save travel time from one place to another. However, traffic congestion is a major problem. Therefore, PT TReKKa intends to develop Metro Kapsul, a mass public transportation system that is suitable for densely populated developed cities. A series of technical analyses and evaluations is necessary to ensure vehicle safety in steady-state curving, traction, and braking. The maximum velocity and acceleration/deceleration in these conditions can be used to decide the development and manufacturing process of Metro Kapsul. The analyses consisted of theoretical and numerical simulations. The theoretical analysis involved applying force equilibrium condition of a rigid body. The simulation was modeled according to a real model of Metro Kapsul. The results showed that both values could be categorized as comfortable based on ASCE 21.2-2008. From this study, the safe longitudinal acceleration and deceleration of Metro Kapsul were obtained, i.e. 0.90 m/s2 and 0.97 m/s2, respectively, while the emergency longitudinal deceleration is 1.25 m/s2. When cornering, the maximum velocity is limited by the centrifugal acceleration, which is 0.6 m/s2. To conclude, the current design of Metro Kapsul is already good in steady-state performance. Further research is required for full dynamic and transient conditions with track irregularities
Analysis of Stress State of Bolts under Different Anchorage Qualities
Get PDFA series of pull-out tests were conducted in order to study the stress states of bolts under different anchorage qualities and to simulate the influence of quality defects in empty-slurry and low-strength mortar anchorage in actual engineering. The tests mainly investigated strain characteristics at different positions of the bolts and the effects of strains at the same positions under different anchorage conditions. The research led to the following conclusions: (1) under ultimate bearing capacity, the strain values decayed the fastest along the length of the bolt in the full-length anchorage, the strain values decayed the slowest in the empty-slurry and low-strength mortar anchorage, and the decaying speed of strains in the empty-slurry mortar anchorage was between that of the above two kinds of anchorages; (2) at almost 50% of the ultimate bearing capacity, the strain values were slightly different between the empty-slurry and low-strength mortar anchorage and the empty-slurry anchorage. Obvious differences in strain values occurred when the bolts were continued to be loaded. The strain values of the full-length anchorage bolts were different from those of the other two kinds of anchorages; (3) from the analysis of stress variation characteristics, the safety reserve was the highest for the full-length anchorage under the condition of ultimate bearing capacity, followed by the empty-slurry mortar anchorage, while the safety reserve was the lowest for the empty-slurry and low-strength mortar anchorage. However, in terms of uniformity of force and utilization of the material, the result was reverse