Study of Bathymetry and Seabed Morphology Changes Around Anak Krakatau Waters of 2018 Post-Eruption

Anak Krakatau is an active volcanic mountain located in the Sunda Strait, Indonesia. On December 22, 2018, this mountain erupted and the flank collapses off into the water. This changes the bathymetry and morphology of the seabed around the waters of Anak Krakatau volcano. This study uses bathymetry data surrounding the Anak Krakatau waters from the Indonesian Navy Hydrographic and Oceanographic Center (PUSHIDROSAL) in 2016 and 2019. The data were obtained by survey using Echosounder Multibeam System MBES EM2040 and EM302. By means of surface analysis method (hillshade), the data were process to observe the bathymetry and seabed morphology changes around the Anak Krakatau volcano waters by the eruption. The results of bathymetry data processing show a depth change of about 25 m, with the lowest value in 2016 ranging from -250,328 m and in 2019 ranging from -226.12 m. The average value of the slope of the seabed in 2016 was 5.31° and 4.98° in 2019.

Penerapan Persamaan Trend Surface Analysis untuk Pemisahan Anomali Residual dan Regional pada Data Gayaberat

The separation of regional anomalies and residual anomalies in gravity data is an important part in interpreting gravity data. This process aims to obtain gravity anomalies that have been associated with exploration targets. The Trend Surface Analysis method is a mathematical approach to the earth field that can be used to separate maps into regional components and local components. The application of this method into gravity data can be used to separate regional anomalies and residual anomalies. The process of processing the trend surface analysis method can be done using Microsoft Excel. This method is tested first on synthetic gravity data, the purpose of this test is to determine the performance of the trend surface analysis method in performing anomaly separation. Based on the test results of the trend surface analysis method on synthetic gravity data, it was found that this method was quite good at separating regional anomalies and residual anomalies. This is evidenced by the anomalous pattern that is already the same between the regional gravity anomaly resulting from the separation of the anomaly using the trend surface analysis method and the regional anomaly resulting from synthetic data. The same anomaly pattern can also be seen in the residual anomaly resulting from the separation of the anomaly using the trend surface analysis method with the residual anomaly resulting from synthetic data. The application of the trend surface analysis method to field data has been carried out by producing regional anomalies and residual anomalies. This method is very good at separating regional anomalies and residual anomalies, especially in regional anomalies located at deep depths.Pemisahan anomali regional dan anomali residual pada data gayaberat merupakan bagian penting dalam melakukan interpretasi data gayaberat. Proses ini bertujuan untuk mendapatkan anomali gayaberat yang sudah berasosiasi dengan target eksplorasi. Metode Trend Surface Analysis merupakan teknik pendekatan matematika pada bidang kebumian yang dapat digunakan untuk memisahkan peta kedalam komponen regional dan komponen lokal. Penerapan metode ini ke dalam data gayaberat dapat digunakan untuk memisahkan anomali regional dan anomali residual. Proses pengolahan metode trend surface analysis dapat dilakukan dengan menggunakan microsoft excel. Metode ini diuji terlebih dahulu pada data gayaberat sintetis, tujuan pengujian ini adalah untuk mengetahui performa metode trend surface analysis dalam melakukan pemisahan anomali. Berdasarkan hasil pengujian metode trend surface analysis pada data gayaberat sintetis didapatkan bahwa metode ini cukup baik dalam memisahkan anomali regional dan anomali residual. Hal ini dibuktikan pada pola anomali yang sudah sama antara anomali gayaberat regional hasil pemisahan anomali metode trend surface analysis dengan anomali regional hasil data sintetis. Pola anomali yang sama juga dapat dilihat pada anomali residual hasil pemisahan anomali metode trend surface analysis dengan anomali residual hasil data sintetis. Penerapan metode trend surface analysis pada data lapangan telah dilakukan dengan menghasilkan anomali regional dan anomali residual. Metode ini sangat baik dalam memisahkan anomali regional dan anomali residual terutama pada anomali regional yang berada pada kedalaman dalam

Waste Tile Usage Effect on the Sandy Subgrade Stabilized with Emulsion Bitumen Performance

Improving the subgrade performance and increasing their efficiency can lead to improving the operation and increasing the life of the pavement. One of the common solutions to improve the resistance and engineering properties of the soils is using the stabilizing materials. Using the waste materials as a stabilizer in the soil can lead to a reduction in project costs and help the protection from the environment. In this study, emulsion bitumen and crushed waste tile are used to stabilize the sand dune which is soil with low bearing capacity and resistance properties. In the present study, the emulsion bitumen and crushed waste tile have been used. The effect of dimensions and percentage of crushed tile with different percentages of emulsion bitumen on the compressive pressure and bearing capacity as well as the compressive strength after applying freeze-thaw cycle. The results indicate that the addition of crushed waste tile increases the compression strength and bearing capacity and the tile with a higher dimension has shown more effectiveness. Applying the freeze-thaw cycle has reduced the compression strength and increasing the number of cycles has increased the resistance drop rate. Soil stabilized with coarse-grained tile has more resistance drop rate which increases by increasing the tile percentage. Then, the 3D graph and the recommended function related to each parameter investigated in the test were provided using the response surface analysis method.

Process Optimization and Formation Analysis of Friction Plug Welding of 6082 Aluminum Alloy

The response surface analysis method was used to systematically study the effect of various parameters on the tensile strength of 6082 aluminum alloy friction plug welding (FPW) joints in this work. The fluidity of the joint and microstructure were observed with a metallurgical microscope. Combined with the temperature field and force analysis, the reason why the root of the joint appears as a weak zone was explained. The results showed that the degree of influence on the tensile strength of FPW joints was rotational speed > upsetting speed > welding time. The optimal FPW joint was obtained when the rotational speed was 2254 rpm, the upsetting speed was 2 mm/s, and the welding time was 25 s, so the tensile strength could reach 262.34 MPa. The microstructure of the FPW joint appeared heterogeneous. According to the different plastic metal fluidities of the joint, it could be divided into four areas. The interaction force at the friction interface was not strong at the root of the FPW joint, so the root often becomes the weak area of the FPW joint.

Influence factors and effect prediction model of the tertiary migrations of remaining oil

Worldwide, for older fields that are in the late stages of production period, production wells that lose production value due to high water cut are usually shut down. In this situation, the remaining oil in the reservoir will be re-enriched under the influence of gravity differentiation and capillary forces. Production practices find when the production well is closed for a long time and then opened for restarting production, the water cut drops dramatically and the output rise sharply. In order to anticipate the effects of enrichment of remaining oil in the reservoir, this paper analyzes 10 influencing factors respectively. Secondly, change of water cut before and after shut-in is used as the evaluation index of residual oil enrichment effect. Numerical simulation method is used to simulate the influence of different factors on the effect of external migrations of remaining oil at different levels. Grey correlation analysis is utilized to rank the correlation of 10 factors on residual oil enrichment and then we can get the main controlling factors affecting residual oil enrichment. Finally, the response surface analysis method is used to establish a 5-factor 3-level model, and the corresponding prediction results are obtained through numerical simulation experiments. The main control factors are fitted to obtain the prediction formula of the remaining oil enrichment effect. As a result, we can use the prediction formula to forecast the enrichment effect of remaining oil under different reservoir parameters.

Research and Exploration on the Process of mangosteen Compound Effervescent Tablets

This article mainly studies a new type of compound effervescent tablet for hot pot soup base, which is made of mangosteen as the main material, adding mangosteen glycoside and kumquat to improve the taste, and adding starch slurry and PEG-6000 as a granulating agent. A single factor test was used to select the optimal level of each factor, the sensory score was used as the response value, and the response surface analysis method was used to optimize the formulation of the compound effervescent tablet, and the moisture absorption rate and sensory condition of the finished tablet after several days of placement were determined. The results showed that the optimized main formula of mangosteen compound effervescent tablets was: mangosteen powder 5.3%, kumquat powder 1.3%, mangosteen glycoside 1.3%, effervescent disintegrant 90.7%, of which citric acid: bicarbonate Sodium is 1.6:1. In this process, starch slurry and PEG-6000 are used as the granulation agent for the semi-dry tableting method. The composite effervescent tablet prepared after drying at 50°C for 3 hours is sweet and sour, rich in special aroma, short in foaming time, and has the lowest moisture absorption rate. The sensory score was 94.96 points.

Multi-Scale Control of Bunsen Section in Iodine-Sulphur Thermochemical Cycle Process

Hydrogen is considered as an environmental friendly energy carrier but its actual impact on the environment depends on the way it is produced. A strategy of plant-wide modelling and advanced process control with optimization is currently developed for the Hydrogen production via the Iodine-Sulphur thermochemical cycle process. The objectives of this paper are two-folds: (1) to optimize the trade-off between steady-state profitability and dynamic operability of the Bunsen section subject to multiple constraints, and (2) to design practical control strategy based on the multi-scale control concept. A multi-scale modelling for the Bunsen section in the Hydrogen production via the Iodine-Sulphur thermochemical cycle process is presented. Based on this multi-scale model, a practical control design is developed and applied to Bunsen section. The suitable sets of control variables and manipulated variables are chosen via a sensitivity study incorporating the multivariate Response Surface Analysis method. By dint of simulation study, it can be shown that the proposed control strategy is able to produce a good closed-loop performance where its robustness depends strongly on the selected schemes of Bunsen section. It is worth highlighting that, the proposed multi-scale control strategy demonstrates robust performance in the face of the worst case uncertainty scenario.