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Risk Evaluation Of The Shipyard Supply Chain Process On Ship Repair With The House Of Risk Matrix Method
Full text linkOne of the keys to the success of ship repair is the supply chain (SC) process of materials that arrive on time. However, delays in its implementation were still found due to poor SC risk management. The purpose of the study is to identify risk factors for SC delay, measure risk factors and evaluate risk factors. This study uses the HOR (House of Risk) method which identifies risk variables (risk events and risk agents) and designs mitigation actions. The results of the HOR phase 1 study show an assessment score in the form of Aggregate Risk potential (ARP) which has a high influence on KM repair. Lintas Damai 1 includes: Supplier's unpreparedness in fulfilling orders with a score of 225, the forwarder experienced a delay in scoring 116 and Needs rejuvenation of facilities and transportation with a score of 120 and KM. Shinpo19 includes the quality of materials from suppliers that are of poor quality with a score of 280, materials that are difficult to obtain in the area with a score of 138 and the layout of poorly organized storage warehouses with a score of 92. The results of HOR phase II include mitigation actions to handle risk agents in KM. Lintas Damai 1 includes finding trusted supplier partners, increasing networking with other suppliers, holding tenders with suppliers who are ready and conducting service and checks every month. Meanwhile, KM. Shinpo19 has mitigation actions to handle risk agents, namely replacing materials with the same specifications but still of quality, having supplier connections with quality standards, supervising suppliers so that they comply with quality standards and structuring materials based on their type
SINTESIS SnO2-SiO2 MENGGUNAKAN DAUN KELAPA SAWIT SEBAGAI SUMBER SILIKA POTENSIAL DAN APLIKASINYA SEBAGAI DEKOLORISASI ZAT WARNA
Full text linkPenelitian ini bertujuan untuk mensintesis padatan SnO2-SiO2 dari daun kelapa sawit yang digunakan untuk dekolorisasi malachite green oxalate. Daun kelapa sawit disiapkan melalui pencucian dengan menggunakan HCl 10%. SnO2-SiO2 disintesis menggunakan metode solid state dengan bantuan sedikit pelarut. Hasil sintesis dikarakterisasi menggunakan X-ray Diffractometer (XRD) X-Ray Fluoresence (XRF), dan Fourier Transform Infrared Spectroscopy (FTIR). Analisis XRD memperlihatkan SnO2-SiO2 memiliki fasa amorf untuk SiO2 dan kristal SnO2. Analisis FTIR memperlihatkan puncak Si-O-Si dan O-Si-O pada bilangan gelombang 1067 cm-1 dan 796 cm-1 serta puncak Sn-O-Sn pada bilangan gelombang 542 cm-1. SnO2-SiO2 menunjukkan dekolorisasi pada proses dekolorisasi malachite green oxalate. Persentase efisiensi dekolorisasi dan kapasitas terbaik didapatkan pada perlakuan SnO2-SiO2 pada lama penyinaran 180 menit dengan persentase efisiensi dekolorisasi 46,33 % dengan kapasitasi 6,952 mg/g. Model kinetika dan isoterm yang didapatkan dalam proses dekolorisasi MGO oleh SnO2-SiO2 merupakan model kinetika reaksi orde semu pertama dengan nilai konstanta -0,0135 menit-1 dan Model isoterm Freundlich dengan nilai Kf 16.545 L/mg. Kinerja dekolorisasi yang dihasilkan merupakan hasil sinergis antara SnO2 dan padatan hasil pembakaran daun kelapa sawit
Studi Pemilihan Alternatif Perkuatan Timbunan Badan Jalan di Atas Tanah Lunak dengan Metode Elemen Hingga dan Sistem Pengambilan Keputusan
Full text linkToll road construction often encounters geotechnical challenges due to soft soil conditions, which can significantly affect embankment stability, as observed on the Balikpapan–Samarinda Toll Road at STA 22+300, NSPT value is ≤ 6 up to a depth of 10 metres. This study aims to analyse the stability of the road embankment and determine an effective and efficient soil reinforcement solution. Slope stability analysis was performed using the finite element method with Plaxis 2D, while decision-making employed the pairwise comparison and simple additive weighting methods. The existing condition analysis revealed a factor of safety of 0.9852 and a settlement of 32.02 cm. The combination of mini piles and geotextiles demonstrated the best performance, increasing the factor of safety to 1.552 and reducing settlement to 13.03 cm. With the highest decision-making preference weight of 0.8989, this alternative was identified as the optimal solution, offering adequate stability, relatively low settlement, and cost efficiency compared to the spun pile–geotextile combination
Effect of Sidoarjo Mud Inoculant and Bacillus subtilis on The Degradation of Tofu Liquid Waste in Microbial Fuel Cell Continuous Series Reactors
Full text linkThe tofu industry in Indonesia generates large amounts of liquid waste with high BOD and COD, causing significant environmental impact. Microbial Fuel Cells (MFC) offer a sustainable solution for treating organic waste while generating electricity. Effective treatment of tofu liquid waste is essential. This study explores the use of Sidoarjo mud and Bacillus subtilis as inoculants in MFC systems, integrated with an advanced reactor design for improved degradation of pollutants. A Continuous Series Reactor was employed, equipped with an auto dosing pump for precise substrate feeding, optimizing microbial activity. The system was monitored using an Arduino Mega data logger and an ESP01 module for remote data transmission. The effectiveness of Sidoarjo mud and Bacillus subtilis was tested by measuring BOD, COD, and protein removal, with different inoculant combinations compared to a control group. The control group achieved BOD and COD removal rates of 70.43% and 47.92%, respectively. Sidoarjo mud alone improved these to 94.30% and 91.84%, while combining Sidoarjo mud with Bacillus subtilis increased removal rates to 94.70% and 92.55%. Protein degradation also improved by 79.79% with Bacillus subtilis. Sidoarjo mud and Bacillus subtilis effectively enhance waste degradation in MFC systems, providing a sustainable solution for tofu waste treatment
Vapor – Liquid Equilibrium of Linalool + β- Caryophyllene and α-Pinene + Linalool at Pressures of 30 and 60 kPa
Full text linkThis research aims to obtain equilibrium data from essential oils, namely lavender oil. Lavender flowers are composed of several ingredients, such as essential oils (1-3%), alpha-pinene (0.22%), camphene (0.06%), beta-myrcene (5.33%), cymene (0.30%), limonene (1.06%). %), cineol (0.51%), linalool (26.12%), borneol (1.21%), terpinine-4-ol (4.64%), linalyl acetate (26.32%), geranyl acetate (2.14%), and caryophyllene (7.55%). This research focuses on determining vapor-liquid equilibrium (VLE) data for the binary systems Linalool + β-Caryophyllene and α-Pinene + Linalool at vacuum pressure of 30 kPa and 60 kPa. Research was conducted to support the equilibrium data for distillation process in the essential oil industry, by exploring the characteristics of VLE which is an important parameter in distillation column design. Experiments used a modified Othmer type ebulliometer and composition measurements were carried out using Gas Chromatography-Mass Spectrometry (GC-MS). The equilibrium data were correlated using Wilson, NRTL, and UNIQUAC model equations. The thermodynamic consistency tests have been performed using Wisniak Method. The research results showed that the VLE values obtained are thermodynamically consistent and the model used can correlate equilibrium with satisfactory accuracy. It was obtained from experimental data that for the Linalool + β-Caryophyllene system had the largest Average Absolute Deviation in temperature (AAD T) value of 0.74% and for the Alpha Pinene + Linalool system had the largest AAD T with a value of 0.28% for both pressures
Comparison of ARIMA, LSTM, and Ensemble Averaging Models for Short-Term and Long- Term Forecasting of Non-Stationary Time Series Data
Full text linkThis study aims to forecast the highest weekly selling rate of the Indonesian Rupiah (IDR) against the US Dollar (USD) and identify the most accurate model among ARIMA, LSTM, and Ensemble Averaging. The evaluation results indicate that ARIMA achieves an accuracy of 97.75%, demonstrating strong performance in short-term forecasting, while LSTM achieves 99.98% accuracy, excelling in capturing complex and dynamic patterns in long-term predictions. The Ensemble Averaging approach attains the highest accuracy of 99.99%, proving to be the optimal solution by combining ARIMA’s stability with LSTM’s adaptability, resulting in more precise and stable predictions. The findings of this study highlight that the ensemble approach is more effective than individual models, as it balances accuracy and prediction stability across various forecasting scenarios. This method serves as a reliable tool for addressing market volatility and contributes significantly to the advancement of financial and economic forecasting techniques that are more adaptive and accurate
Application of Bisecting K-Means Method in Grouping Earthquake Data (Case Study: Earthquakes in Indonesia 2023)
Full text linkEarthquakes are natural disasters that frequently occur in Indonesia, threatening the safety and resilience of its communities. This study aims to analyze the descriptive and clustering results of earthquake data in Indonesia. The data used in this study include various variables such as latitude, longitude, magnitude, and depth as the main features. The method used in this study is Bisecting K-means, and the Davies Bouldin Index test is used to determine the number of clusters. The study results indicate the formation of 3 groups, where cluster 1 falls into the deep earthquake category, cluster 3 falls into the intermediate earthquake category, and cluster 2 falls into the shallow earthquake category, with an average Davies-Bouldin Index value of 0.4758
Computational Study on Urea Concentration Profiles in Hemodialysis Hollow Fiber Membranes Under Different Blood Flow Conditions
Full text linkKidney failure significantly impairs physiological functions, primarily due to the accumulation of urea in the bloodstream. When renal function drops below 75%, hemodialysis becomes a crucial therapeutic intervention. This study investigates the performance of a hollow fiber dialyzer, consisting of a shell-side dialysate flow, a semi-permeable membrane, and internal capillaries for blood flow. The main objective is to develop a theoretical model describing urea mass transfer through the membrane during hemodialysis. The analysis focuses on the effect of blood flow rate on urea concentration distribution across the tube, membrane, and shell regions in both axial and radial directions. Additionally, the influence of membrane length and dialysate flow rate on urea clearance is examined. Simulation results indicate that higher blood flow rates lead to elevated urea concentrations at the tube outlet, suggesting reduced diffusion into the dialysate compartment. In contrast, increasing membrane length enhances urea clearance. Interestingly, the dialysate flow rate shows minimal impact on clearance efficiency. Under a fixed dialysate flow rate of 500 mL/min and a membrane length of 27 cm, the calculated urea clearance values were 21.95%, 17.06%, 14.31%, and 12.52% for blood flow rates of 200, 300, 400, and 500 mL/min, respectivel
Curating the City: Begandring Soerabaia and the Production of Public Space
Full text linkThis paper examines the role of the heritage community of Begandring Soerabaia in the production of public space employing Henri Lefebvre's concept of social space as a theoretical framework. Focusing on the "Parade Oud Soerabaja" photography exhibition held at Balai Pemuda Surabaya, the study explores how historical narratives and archival materials are mobilized to generate immersive, socially meaningful experiences. It argues that Begandring’s initiatives—through cultural programming, community gatherings, and dialogic engagement—actively contribute to the transformation of urban heritage spaces into dynamic sites of memory, identity, and civic interaction. The exhibition is situated within Lefebvre's spatial triad, and this study highlights how Balai Pemuda functions as a living space shaped by historical continuity, cultural exchange, and communal agency. Finally, the paper emphasizes the significance of grassroots heritage activism in reconfiguring public spaces and preserving urban cultural memor
IDENTIFICATION OF AREAS AT RISK OF ABRASION APPLICATION OF ELECTRICAL RESISTIVITY TOMOGRAPHY (ERT) METHOD ON NANGAI BEACH, NORTH BENGKULU
Full text linkA study of the underground structures in areas prone to abrasion of Nangai Beach, North Bengkulu Regency. In this study, 2D images of the subsurface structure at the Nangai Beach site were obtained using the Wenner-Schlumberger configuration, while 3D representations were obtained using the electrical resistivity technique (ERT). To protect coastal materials, the main objective of this research is to identify rock types that are resistant to seawater erosion and measure the resistivity of rocks that can be eroded. In addition, software (ERT LAB 64, View Lab 3D and Res2Dinv) was used to analyze the data by processing it and displaying an image of the resistivity value. The interpretation results show that the coastal zone of the study area is dominated by clays with resistivity (>34 Ωm). The shoreline of Nangai beach consists of shale clay (>> 437 Ωm). Rocks having a resistivity value (437 Ωm) are not easily eroded by erosion in shale clay. This is because the rocks known as shale clay have low porosity, resulting in compact rock density. Restoring damaged soil and planting trees near the coast are two ways to slow down the abrasion process. Keywords: Abrasion, Electrical Resistivity tomography (ERT), 2D/3D, Nangai Beac