scholarly journals ANALISIS PENGARUH NILAI KONDUKTIVITAS HIDRAULIK DAN DISPERSIVITAS DINAMIK TERHADAP REMEDIASI AIR TANAH MENGGUNAKAN SIMULASI NUMERIK

2021 ◽  
Vol 12 (2) ◽  
pp. 107-118
Author(s):  
Agus Mochamad Ramdhan ◽  
Arifin Arifin ◽  
Erik Hermawan ◽  
Lambok M. Hutasoit
Keyword(s):  
Numerical Simulation ◽  
Sensitivity Analysis ◽  
Hydraulic Conductivity ◽  
Groundwater Remediation ◽  
Flow Simulation ◽  
Pumping Wells ◽  
Time Required ◽  
Close Distance ◽  
High Hydraulic Conductivity

Groundwater remediation is one of the solutions to restore the contaminated groundwater. This study was conducted to determine the effect of hydraulic conductivity and dynamic dispersivity on the groundwater remediation effectiveness. As a case study, in 2020, in an area located in Balikpapan, groundwater remediation will be carried out by injecting water containing NaOH through five wells and pumping it back through five wells to form a cycle. The method used is a numerical simulation consisting of groundwater flow simulation, mass transport, and sensitivity analysis. The results show that it takes 124 to 300 days for the injected NaOH to arrive at the pumping wells. The sensitivity analysis results show that when the hydraulic conductivity value is ten times greater, the time required is reduced to 84 to 172 days. Meanwhile, when the dynamic dispersivity is twice larger, the time required is reduced to 75 to 189 days. These results indicate that the groundwater remediation method will be effective for aquifers with high hydraulic conductivity and dynamic dispersivity values. For the study area, the groundwater remediation is suggested to be carried out by increasing the number of injection and pumping wells with a relatively close distance, i.e., around 10 meters, so that NaOH arrives at the pumping wells more quickly.Keywords: groundwater, remediation, hydraulic conductivity, dynamic dispersivity, numerical simulation

scholarly journals Analisis Finansial Pengolahan Minyak Jahe di Aceh Besar (Studi Kasus pada PT. Raz Intan)

2017 ◽  
Vol 2 (2) ◽  
pp. 302-313
Author(s):  
Adelia Kusfianda ◽  
Teuku Makmur ◽  
Edy Marsudi
Keyword(s):  
Sensitivity Analysis ◽  
Production Cost ◽  
Case Study Method ◽  
Eligibility Criteria ◽  
Oil Processing ◽  
Cost Of Production ◽  
Time Required ◽  
The Cost

Abstract Ginger oil has many functions, such as is used in the cosmetics industry, food, aromateraphy, and pharmaceuticals. The purpose of this study is to determine the feasibility of ginger oil processing at the PT. Raz Intan financially. This research was conducted at PT. Raz Desa Intan Jurong Peujera Ingin Jaya subdistrict, Aceh Besar District by using the case study method. Data were analyzed using the feasibility of the eligibility criteria, namely NPV, Net B / C, IRR, BEP, and sensitivity analysis. The results of the analysis of the feasibility of ginger oil at PT. Raz diamonds indicate the business is eligible to run, which is the NPV Rp 446 242 245, Net B / C 2.64, IRR 49.50%, and BEP amounted to 5,358 or length of time required for the BEP is 5 years 4 month 8 days. From a sensitivity analysis with the calculated cost of production criteria (cost) increased 10% and the reception (benefit) remain NPV Rp 83,061,190, Net B / C of 1.27, IRR of 23.46% and BEP obtained in year 6 months to 10 days to 4. for the cost of production (cost) fixed and reception (benefit) fell by 10% NPV Rp 38,436,965, Net B / C of 1.14, IRR of 20.38% and BEP obtained in the year to 6 months to 10 days to 16. Keywords: Ginger, Ginger Oil, Feasibility Abstrak – Minyak jahe memiliki banyak fungsi, diantaranya digunakan dalam industri  kosmetik, makanan, aromateraphy, dan farmasi. Tujuan penelitian ini yaitu untuk mengetahui kelayakan usaha pengolahan minyak jahe pada PT. Raz Intan secara finansial. Penelitian ini dilakukan di PT. Raz Intan Desa Jurong Peujera Kecamatan Ingin Jaya Kabupaten Aceh Besar dengan menggunakan metode studi kasus. Data kelayakan usaha dianalisis menggunakan kriteria kelayakan yaitu NPV, Net B/C, IRR, BEP, dan analisis sensitivitas. Hasil analisis kelayakan usaha minyak jahe pada PT. Raz Intan menunjukkan usaha tersebut layak dijalankan, dimana nilai NPV sebesar Rp 446.242.245, Net B/C sebesar 2,64, IRR sebesar 49,50%, dan BEP sebesar 5,358 atau lamanya waktu yang dibutuhkan untuk terjadinya BEP yaitu 5 tahun 4 bulan 8 hari. Dari analisis sensitivitas dengan hasil perhitungan kriteria biaya produksi (cost) naik 10% dan penerimaan (benefit) tetap diperoleh NPV sebesar Rp 83.061.190, Net B/C sebesar 1,27, IRR sebesar 23,46% dan BEP diperoleh pada tahun ke 6, bulan ke 10, hari ke 4. Untuk biaya produksi (cost) tetap dan penerimaan (benefit) turun 10% diperoleh NPV sebesar Rp 38.436.965, Net B/C sebesar 1,14, IRR sebesar 20,38% dan BEP diperoleh pada tahun ke 6, bulan ke 10, hari ke 16. Kata Kunci : Jahe, Minyak Jahe, Kelayakan Usaha

scholarly journals Flow Simulation and Energy Loss Estimation in the Nappe Flow Regime of Stepped Spillways with Inclined Steps and End Sill: A Numerical Approach

2016 ◽  
Vol 2 (9) ◽  
pp. 426-437 ◽  
Author(s):  
Amirmasoud Hamedi ◽  
Mohammad Hajigholizadeh ◽  
Abbas Mansoori
Keyword(s):  
Numerical Simulation ◽  
Energy Loss ◽  
Flow Pattern ◽  
Flow Direction ◽  
Low Cost ◽  
Flow Simulation ◽  
Numerical Approach ◽  
Stepped Spillway ◽  
Stepped Spillways ◽  
Time Required

Recently, the usage of stepped spillways, as energy dissipaters, has increased and led to a reduction in the size of the stilling basin. Extensive experimental considerations, plus the high cost and extended time required for laboratory methods, are among the major issues that require precise attention to determine optimal step design. This research deals with comparing the 2-D numerical simulation and experimental description in stepped spillways equipped with inclined steps and end sill together and presents a brisk, reliable, low-cost, and non-experimental approach to designing the steps. In this new type and complicated geometry, simulation is more complicated than horizontal steps, because it needs more accuracy around the end sills. The VOF Method and the k-ε standard turbulence model are proposed to simulate the flow pattern and evaluate the energy loss over stepped spillway. Energy dissipations obtained through the numerical approach have been compared with laboratory measurements and demonstrate reasonable agreement. Also, the flow pattern, velocity vectors and flow direction resulted from numerical simulation is in a good agreement with the experimental results.

Rethinking Rehabilitation: Application of the SOTE model to soil rehabilitation following salinity and sodicity induced degradation

2021 ◽  
Author(s):  
Isaac Kramer ◽  
Yuval Bayer ◽  
Yair Mau
Keyword(s):  
Sensitivity Analysis ◽  
Hydraulic Conductivity ◽  
Experimental Evidence ◽  
Significant Degree ◽  
Climatic Conditions ◽  
Test Case ◽  
Increased Risk ◽  
Time Required ◽  
Parameter Values ◽  
Irrigation Waters

<p>If not carefully managed, use of saline and sodic irrigation waters, a common practice in dryland regions, has the potential to cause significant harm to soils. Application of saline and sodic irrigation waters can lead to reductions in hydraulic conductivity, Ks, the mechanisms of which (e.g., slaking, swelling, clay dispersion) have been the focus of a vast body of scientific literature. The rehabilitation process, by contrast, is far less understood. Despite experimental evidence showing a significant degree of irreversibility, traditionally models have treated the degradation and rehabilitation processes as reversible. We demonstrate how this assumption obfuscates our ability to analyze the risk of long-term degradation and to estimate the resources and time required to rehabilitate. We achieve this by using the SOTE model — a minimalistic model that can be used to study dynamics of soil water content, salinity, and sodicity, as driven by irrigation practices and climatic conditions. Crucially, SOTE also accounts for the feedback between changing salinity and sodicity and soil Ks. This feedback includes irreversible changes in hydraulic conductivity, such that a soil’s history of degradation and rehabilitation informs its future state. We compare SOTE to existing models, which do not include hysteresis in Ks, and demonstrate that SOTE predicts more gradual rehabilitation of degraded soils, in line with the limited experimental evidence that has examined this question. For the test case of a degraded soil in a typical Mediterranean climate, SOTE forecasts that rehabilitation requires 50% more time and water resources, in comparison to models without hysteresis. This difference underscores the need to limit the risk of potential degradation, which SOTE also shows increases by 50% when hysteresis is accounted for. A sensitivity analysis indicates that SOTE is most sensitive to parameters connected to soil texture. The sensitivity analysis further indicates that our results are robust -- under all ranges of parameter values SOTE continues to forecast greater time requirements for rehabilitation and increased risk of soil degradation.</p>

scholarly journals Geochemical equilibrium determination using an artificial neural network in compositional reservoir flow simulation

2019 ◽  
Vol 24 (2) ◽  
pp. 697-707 ◽  
Author(s):  
Dominique Guérillot ◽  
Jérémie Bruyelle
Keyword(s):  
Flow Simulation ◽  
Fluid Injection ◽  
Equilibrium Calculation ◽  
Transfer Processes ◽  
Reservoir Flow ◽  
Equilibrium And Kinetics ◽  
Geological Formation ◽  
Artificial Neural ◽  
Time Required

AbstractThe fluid injection in sedimentary formations may generate geochemical interactions between the fluids and the rock minerals, e.g., CO2 storage in a depleted reservoir or a saline aquifer. To simulate such reactive transfer processes, geochemical equations (equilibrium and kinetics equations) are coupled with compositional flows in porous media in order to represent, for example, precipitation/dissolution phenomena. The aim of the decoupled approach proposed consists in replacing the geochemical equilibrium solver with a substitute method to bypass the huge consuming time required to balance the geochemical system while keeping an accurate equilibrium calculation. This paper focuses on the use of artificial neural networks (ANN) to determine the geochemical equilibrium instead of solving geochemical equations system. To illustrate the proposed workflow, a 3D case study of CO2 storage in geological formation is presented.

scholarly journals Sensitivity analysis for interpretation of machine learning based segmentation models in cardiac MRI

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Markus J. Ankenbrand ◽  
Liliia Shainberg ◽  
Michael Hock ◽  
David Lohr ◽  
Laura M. Schreiber
Keyword(s):  
Neural Networks ◽  
Sensitivity Analysis ◽  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Cardiac Mri ◽  
Magnetic Resonance Images ◽  
Model Interpretation ◽  
First Case ◽  
Segmentation Models

Abstract Background Image segmentation is a common task in medical imaging e.g., for volumetry analysis in cardiac MRI. Artificial neural networks are used to automate this task with performance similar to manual operators. However, this performance is only achieved in the narrow tasks networks are trained on. Performance drops dramatically when data characteristics differ from the training set properties. Moreover, neural networks are commonly considered black boxes, because it is hard to understand how they make decisions and why they fail. Therefore, it is also hard to predict whether they will generalize and work well with new data. Here we present a generic method for segmentation model interpretation. Sensitivity analysis is an approach where model input is modified in a controlled manner and the effect of these modifications on the model output is evaluated. This method yields insights into the sensitivity of the model to these alterations and therefore to the importance of certain features on segmentation performance. Results We present an open-source Python library (misas), that facilitates the use of sensitivity analysis with arbitrary data and models. We show that this method is a suitable approach to answer practical questions regarding use and functionality of segmentation models. We demonstrate this in two case studies on cardiac magnetic resonance imaging. The first case study explores the suitability of a published network for use on a public dataset the network has not been trained on. The second case study demonstrates how sensitivity analysis can be used to evaluate the robustness of a newly trained model. Conclusions Sensitivity analysis is a useful tool for deep learning developers as well as users such as clinicians. It extends their toolbox, enabling and improving interpretability of segmentation models. Enhancing our understanding of neural networks through sensitivity analysis also assists in decision making. Although demonstrated only on cardiac magnetic resonance images this approach and software are much more broadly applicable.

scholarly journals Evaluating Life Cycle of Buildings Using an Integrated Approach Based on Quantitative-Qualitative and Simplified Best-Worst Methods (QQM-SBWM)

2021 ◽  
Vol 13 (8) ◽  
pp. 4487
Author(s):  
Maghsoud Amiri ◽  
Mohammad Hashemi-Tabatabaei ◽  
Mohammad Ghahremanloo ◽  
Mehdi Keshavarz-Ghorabaee ◽  
Edmundas Kazimieras Zavadskas ◽  
...  
Keyword(s):  
Life Cycle ◽  
Computer Software ◽  
Integrated Approach ◽  
Comfort Level ◽  
Combination Method ◽  
New Combination ◽  
Numerical Examples ◽  
Environmental Consequences ◽  
Time Required

Evaluating the life cycle of buildings is a valuable tool for assessing sustainability and analyzing environmental consequences throughout the construction operations of buildings. In this study, in order to determine the importance of building life cycle evaluation indicators, a new combination method was used based on a quantitative-qualitative method (QQM) and a simplified best-worst method (SBWM). The SBWM method was used because it simplifies BWM calculations and does not require solving complex mathematical models. Reducing the time required to perform calculations and eliminating the need for complicated computer software are among the advantages of the proposed method. The QQM method has also been used due to its ability to evaluate quantitative and qualitative criteria simultaneously. The feasibility and applicability of the SBWM were examined using three numerical examples and a case study, and the results were evaluated. The results of the case study showed that the criteria of the estimated cost, comfort level, and basic floor area were, in order, the most important criteria among the others. The results of the numerical examples and the case study showed that the proposed method had a lower total deviation (TD) compared to the basic BWM. Sensitivity analysis results also confirmed that the proposed approach has a high degree of robustness for ranking and weighting criteria.

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