WATERWALL TUBE BOILER DAMAGE ANALYSIS IN A 150 MW STEAM POWER PLANT

Steam Power Plant which uses environmentally friendly types of boilers such as CFB (Circulating Fluidized Bed) type boilers. Failure of the boiler pipe has a big impact on the process or the losses it causes. This study will analyze the failures that occur in the boiler tube waterwall of PT. DSSP Power South Sumatra which suffered damage by testing chemical content, hardness test, tensile test, metallographic testing, and Scanning Electron Microscopy (SEM) testing. The test results show that the composition contained in the boiler tube waterwall is not in accordance with the standards, there are some elements that are lower than the specifications. The mechanical properties of watertube boilers are still in accordance with the standards. Leaks that occur in pipes are caused by creeping cracks and causing fatigue so that the damage begins with 'thermal fatigue' which causes cracks in certain weld seams. These open cracks produce leaks which cause the discharge of high velocity fluids which hit adjacent surfaces creating an 'erosion' failure which then results in thinning of the walls of the tube. The thinning of the walls then causes another leak. Therefore, a series of erosions occurred which resulted in several leaks. The fact is that the failure is preferably located in the area of the weld seam which makes it the root cause of the failur

Review on Odor Localization

In this paper, the importance of odor localization isexplained. The researchers that investigated the experimentsand applications of odor localization using static sensors, mobilesensors (that were integrated in single robot, multi robot, andswarm robot) are described. However, there are some difficultiesfaced by the researchers in applying the mobile robots in the realsituation, such as: the speed of mobile robots are not as fast asthe odor patches transporting and the use of more than onesensor in mobile robot can make noises or errors. In the future,the plume finding in the uncertain environment and thechallenges mentioned above will be the authors’ consideration

Optimization of stir casting method of aluminum matrix composite (AMC) for the hardness properties by using Taguchi method

Aluminum matrix composite (AMC) was fabricated using stir casting with fly ash and SiC as reinforcing materials. In this work, Taguchi optimization technique was utilized to analyze the significant contributions of stir casting parameters on the hardness properties of AMC. For this reason, stir casting was carried out by utilizing the combination of process parameters based on three-level of L9 Taguchi. The signal-to-noise (S/N) and the analysis of variance (ANOVA) were used to find the optimum levels and to indicate the impact of the process parameters on the hardness properties. The results show that some of process parameters have significant effect on the hardness, by comparing with the other three sintering factors, the composition of reinforcement materials gave the most significant effect on the hardness

Optimum performance of green machining on thin walled Ti6AL4V using RSM and ANN in terms of cutting force and surface roughness

Thin walled titanium alloys are mostly applied in the aerospace industry owing to their favorable characteristic such as high strength-to-weight ratio. Besides vibration, the friction at the cutting zone in milling of thin-walled Ti6Al4V will create inconsistencies in the cutting force and increase the surface roughness. Previous researchers reported the use of vegetable oils in machining metal as an effort towards green machining in reducing the undesirable cutting friction. Machining experiments were conducted under Minimum Quantity Lubrication (MQL) using coconut oil as cutting fluid, which has better oxidative stability than other vegetable oil. Uncoated carbide tools were used in this milling experiment. The influence of cutting speed, feed and depth of cut on cutting force and surface roughness were modeled using response surface methodology (RSM) and artificial neural network (ANN). Experimental machining results indicated that ANN model prediction was more accurate compared to the RSM model. The maximum cutting force and surface roughness values recorded are 14.89 N, and 0.161 μm under machining conditions of 125 m/min cutting speed, 0.04 mm/tooth feed, 0.25 mm radial depth of cut (DOC) and 5 mm axial DOC

Intelligent Sensing Using Metal Oxide Semiconductor Based-on Support Vector Machine for Odor Classification

Classifying odor in real experiment presents some challenges, especially the uncertainty of the odor concentration and dispersion that can lead to a difficulty in obtaining an accurate datasets. In this study, to enhance the accuracy, datasets arrangement based on MOS sensors parameters using SVM approach for odor classification is proposed. The sensors are tested to determine the sensors' time response, sensors' peak duration, sensors' sensitivity, and sensors' stability when applied to the various sources at different range. Three sources were used in experimental test, namely: ethanol, methanol, and acetone. The gas sensors characteristics are analyzed in open sampling method to see the sensors' performance in real situation. These performances are considered as the base of choosing the position in collecting the datasets. The sensors in dynamic experiment have average of precision of 93.8-97.0%, the accuracy 93.3-96.7%, and the recall 93.3-96.7%. This values indicates that the collected datasets can support the SVM in improving the intelligent sensing when conducting odor classification work

Odor Localization using Gas Sensor for Mobile Robot

This paper discusses the odor localization using Fuzzy logic algorithm. The concentrations of the source that is sensed by the gas sensors are used as the inputs of the fuzzy. The output of the Fuzzy logic is used to determine the PWM (Pulse Width Modulation) of driver motors of the robot. The path that the robot should track depends on the PWM of the right and left motors of the robot.  When the concentration in the right side of the robot is higher than the middle and the left side, the fuzzy logic will give decision to the robot to move to the right. In that condition, the left motor is in the high speed condition and the right motor is in slow speed condition. Therefore, the robot will move to the right.   The experiment was done in a conditioned room using a robot that is equipped with 3 gas sensors. Although the robot is still needed some improvements in accomplishing its task, the result shows that fuzzy algorithms are effective enough in performing odor localization task in mobile robot

Target Tracking in Mobile Robot under Uncertain Environment using Fuzzy Logic Controller

This paper discusses a design of fuzzy logic algorithm in a robot.   This algorithm is useful for the robot in seeking and reaching the target.  The robot is also accomplished with an ability to avoid obstacles. Although the fuzzy rule that is embedded to the robot is very simple, it gives a good result in target seeking and obstacles avoiding task.   The originality of this research is an approach to the rules that can simplify the task by creating faster track for the robot in uncertain environment.

Challenges in Turbine Flow Metering System: An Overview

This paper presents an overview of turbine flow meter (TFM). State of the art, the basic concept of TFM, and some parameters that influence the robustness of TFM are described. In addition, some challenges that occurred in TFM that can affect the accuracies of the measurement are also analysed. The different meter reading between the manual metering or turbine stand meter and Electronic Volume Corrector (EVC) that occurs in turbine flow meter in oil and gas industries is one of TFM challenges. This difference leads to losses in customers or in industries themselves. A notification system is proposed in this paper. An intelligent system that can determine the occurrence of the error will be embedded to the system. It is hoped that by having the earlier notification, the losses can be decreased

BESARAN ENERGI AKTIVASI DARI OKSIDASI HASIL PENGECORAN ALUMINIUM KALENG MINIMUM YANG MENDAPAT PERLAKUAN PANAS QUENCHING DAN ANNEALING

Thermogravimetry analyzer adalah suatu alat untuk melakukan analisa thermal dimana massa bahan uji akan berbanding terbalik atau berbanding lurus dengan laju temperatur yang meningkat dan fungsi waktu (temperatur meningkat konstan). TGA biasanya digunakan untuk menentukan karakteristik material. Kurva naiknya massa material Aluminium dapat digunakan untuk mengetahui oksidasi. Titik naiknya massa material bisa digunakan untuk menghitung energi aktivasi. Penelitian ini menggunakan alat Thermogravimetry Analyzer (TGA) Exstar SII 7300 dengan 3 (tiga) sampel yang berbeda yaitu: Sampel Non Heat Treatment, Sampel Quenching, Sampel Annealing.  Hasil pengujian didapatkan bahwa energi aktivasi pada keadaan temperatur 400-6500C ramp 10 pada sampel non heat treatment E = 30,137 kJ/mol. Pada quenching E = 23,537 kJ/mol. Pada annealing E = 28,373 kJ/mol