Journal of Engineering and Technological Sciences
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The Combined Use of Terrestrial Laser Scanner and Handheld 3D Scanner for 3D Modeling of Piping Instrumentation at Oil and Gas Company
Get PDFThree-dimensional (3D) models are indispensable in managing, operating, maintaining, and repairing piping instrumentation activities in oil and gas companies. 3D models are expected to provide more interactive and representative information according to actual objects. Several technologies that can be used to generate piping instrumentation 3D maps are Terrestrial Laser Scanner (TLS) and Handheld 3D Scanner (HS). This study aims to create a 3D model of piping instrumentation using a combination of TLS and HS and analyze the results of data validation used for modeling. The results showed that a 3D modeling of piping instrumentation could be generated accurately using a combination of TLS and HS technologies. Merging between the two data is carried out through a cloud-to-cloud registration process based on the geometry of the object by considering the selection of reference data, the similarity of the scale factor, the unit of measure, and the overlap of the two data. The registration error generated in combining these two methods is less than 0.003 m. The resulting model still has drawbacks, which is the absence of coding for the pipe caused by the unavailability of the Piping and Instrumentation Diagram (P&ID) during modeling. The geometric validation of the model size value using reference data and the field size has the largest absolute difference of 0.0034 m with an average absolute deviation of 0.0016 m
Evaluating Direct Pointing and Indirect Cursor Interactions with Fitts' Law in Stereoscopic Environments
Get PDFThe development of virtual environment research has reached the stage of human interaction with three-dimensional (3D) objects. In this study, Fitts' method was used to such interaction techniques in virtual environment, and the Fitts' law applicability in 3D virtual environment was also considered. The experiment included two modes of interaction: direct interaction and indirect interaction that utilize different techniques depending on how users interact with 3D objects. Both interaction techniques were conducted in three indexes of difficulties and three egocentric target distances (a distance from participant to target). Movement time and throughput were measured for each interaction technique. The results show that the direct pointing technique is more efficient for interaction with the targets close to the participant, while the indirect cursor technique may be a viable option for targets further away from participant. Throughputs were found to be significantly higher for the direct pointing technique compared to the indirect cursor technique. The results of the mean movement time were highly correlated with the targets' index of difficulty for all interaction techniques, supporting evidence that Fitts' law can be applied to the interactions in 3D virtual environment. Based on the results, developers of VE application may relate to these findings in designing proper users' interactions
Integrated Magnetotelluric (MT), Gravity and Seismic Study of Lower Kutai Basin Configuration
Get PDFThis work describes a subsurface basin configuration of the Lower Kutai Basin (hereinafter LKB) in East Kalimantan, Indonesia, as inferred from combination of magnetotelluric (MT), seismic, and gravity data. LKB is structurally controlled mainly by the Samarinda Anticlinorium extending in a NNE-SSW direction and is one of the most prolific hydrocarbon basins in Indonesia. The phase tensor analysis of MT data from most stations and frequencies exhibited a 2D character with a relatively low skew (-3° < β < 3°). The geo-electrical strike direction was estimated at N30°E, which is in good agreement with the regional geological strike with a NNE-SSW direction. 2D MT inversion modeling was performed to infer the subsurface resistivity distribution associated with LKB’s configuration. From the integration of MT, seismic and gravity models it was shown that LKB’s configuration is composed mainly of sandstone, black shale, claystone, and basement rocks. The conductive zones of the MT models are associated with thermal alteration of black shale, which changes its mineralization, leading to lower resistivity. Hence, the black shale may be interpreted as potential hydrocarbon source rock in LKB
Curie Point Depth Analysis of Lesugolo Area, East Nusa Tenggara, Indonesia Based on Ground Magnetic Data
Get PDFThe Curie point depth, or magnetic basal depth, of the Lesugolo geothermal area in Ende, Flores Island, East Nusa Tenggara, Indonesia was estimated by performing spectral analysis on spatial magnetic data and transforming it into the frequency domain, resulting in a link between the 2D spectrum of magnetic anomalies and the depths of the top and centroid of the magnetic sources. Shallow Curie point depths of 16 to 18 km were found in the north-northeast to southeast areas of Lesugolo, while deeper depths of 24 to 26 km were found in the southwest. The tectonic setting beneath the central part of Flores Island governs the distribution of the Curie point depths in the area. Shallow Curie point depth zones are associated with high thermal gradients (30 to 34 °C/km) and heat flow (80 to 100 mW/m2). Deep depths, on the other hand, correspond to zones of low thermal gradient (21 to 26 °C/km) and low heat flow (65 to 80 mW/m2). Both the derived thermal gradient and the heat flow maps contribute to a better understanding of the Lesugolo geothermal system’s configuration. This study suggests that the Lesugolo geothermal area’s prospect zone is located in the center of the investigated area, where the Lesugolo normal fault forms its southeastern boundary
The Presence of Trihalomethanes and Haloacetic Acids in Tropical Peat Water
Get PDFThe presence of dissolved organic matter (DOM) in tropical peat water affects the appearance of trihalomethanes (THMs) and haloacetic acids (HAAs) in natural water sources. However, information about the presence of THM and HAA in tropical peat water is still limited. This study was conducted to determine the presence of THMs and HAAs in tropical peat water taken from a canal and a river in Riau Peatland, Indonesia, influenced by the seasons and the tides. DOM was measured by dissolved organic carbon (DOC) and UV254 absorbance. The presence of THMs and HAAs was determined based on total THM4 and HAA5 and correlated with chloride and bromide concentrations. The concentrations of chloride and bromide in the river water were higher than in the canal water because of tidal influence. Total THM4 in canal water reached 22.70 ± 0.90 and 10.78 ± 0.71 µg/L in the dry and rainy seasons, respectively, but only reached 16.64 ± 1.93 and 5.52 ± 0.05 µg/L in the river water. In contrast to THM4, total HAA5 in the river water was higher than in the canal water and reached 104.01 ± 4.67 and 106.39 ± 9.53 µg/L in the dry and rainy seasons, respectively, but only reached 9.83 ± 0.48 and 56.87 ± 6.11 µg/L in the river water. THM4 predominated in the dry season while HAA5 predominated in the rainy season
Coliform Removal in Membrane Bioreactor and Disinfection during Hospital Wastewater Treatment
Get PDFThis study investigated coliform removal from hospital wastewater in a membrane bioreactor (MBR) and disinfection using either chlorine or ozone. A laboratory-scale MBR equipped with a hollow-fiber membrane module was operated with hydraulic retention times varied at 3 and 6 hours. The disinfection of MBR effluent was carried out using either chlorine or ozone with concentrations varied between 1 and 10 mg/l and contact time varied between 1 and 30 min. During 150 days of MBR operation, organic removal efficiencies averaged 96.5% and 97.7% for BOD and 73.6% and 84.1% during its operation at an HRT of 3 and 6 hours respectively. Simultaneously, 6.7 and 6.4 log reduction of total coliforms and 6.2 and 6.1 log reduction of E. coli were achieved under these respective HRT conditions. The use of chlorine for disinfection of MBR effluent could eliminate total coliforms and E. coli completely at >6 and 3 mg/L at 30 min contact time, whereas only >3 and 1 mg/L was required for ozone at the same contact time. There was a significant improvement of disinfection efficacy of solid-free MBR effluent compared to that of activated sludge effluent