| 1. |
- Idris, Alamin, et al.
(författare)
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Grindability and abrasive behavior of coal blends : analysis and prediction
- 2022
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Ingår i: International Journal of Coal Preparation and Utilization. - : Taylor & Francis. - 1939-2699 .- 1939-2702. ; 42:4, s. 1143-1169
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Tidskriftsartikel (refereegranskat)abstract
- Low-grade coals are blended with high-quality coals to meet economic, environmental, and quality specifications. Hence, the grindability and abrasiveness of coal blends are crucial economic and operational parameters. This work evaluates, analyzes, and predicts the grindability and abrasive behavior of coal blends. Three binary coal blends with common low-grade coal were first prepared at various ratios. Blends 1 and 2 were composed of identical and similar ranks, whereas Blend 3 was composed of different ranks. The blends were analyzed using proximate, ultimate analyzers, and a Bomb calorimeter. The grindability and abrasive behavior of the blends were measured using Hardgrove grindability index (HGI) and Yancey, Geer, and Price methods, respectively. Further, the coarser (+75 mu m) and finer (-75 mu m) fractions of HGI experiment were characterized using proximate, ultimate and heating value analyses. The additivity of HGI values was observed for Blend 1 and Blend 2, whereas, the non-additive behavior was observed in Blend 3. Further, the blends' mineral matter contents and abrasiveness index were found to be additive. Several existing models were found to be inaccurate for HGI predictions. Therefore, a new cross-validated model using multi-linear regression was proposed. The model exhibited better HGI predictions of coal blends with a coefficient of determination R-2 = 0.9416.
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| 2. |
- Idris, Alamin, et al.
(författare)
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Modified Bruggeman models for prediction of CO2 permeance in polycarbonate/silica nanocomposite membranes
- 2017
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Ingår i: The Canadian Journal of Chemical Engineering. - : John Wiley & Sons. - 0008-4034 .- 1939-019X. ; 95:12, s. 2398-2409
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Tidskriftsartikel (refereegranskat)abstract
- Abstract The polycarbonate membranes performances are improved by the incorporation of silica nanoparticles into the polymer matrix. Prepared PC/silica nanocomposite membranes with various silica content are considered and the experimental relative permeance of CO2 gas at 200 kPa (2 bar) feed pressure are used as reference in the predictions using the existing theoretical models such as Maxwell-Wagner-Sillar, Bruggeman, Lewis-Nielsen, Pal, and modified Pal models. TEM and BET analysis were used to characterize the silica nanoparticles; FESEM was used to characterize the morphology of the nanocomposite membranes. The TEM image of the silica nanoparticles reveals that the nanoparticles are mostly spherical. BET results reveal that the surface area and pore diameter of the silica nanoparticles are 618.8 m2/g and 0.28 nm, respectively. The existing models have resulted in poor predictions with errors AARE % of 26.52 to 28.02 %. Observation by FESEM image shows that the dispersed particles are surrounded by interfacial voids and rigidified polymer layer. Modified Bruggeman models that consider the interfacial volume show appreciable prediction with AARE 4.59 % being obtained with the pseudo-two-phase Bruggeman model. Moreover, when the model considered pseudo-three-phase morphology, the AARE % value reduced to 3.92 %. Thus, the contribution due to the interfacial rigidified layer was minimal.
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| 3. |
- Jakariya, Md., et al.
(författare)
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ICT-based solution for efficient fecal sludge management : An experience from Bangladesh
- 2023
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Ingår i: Heliyon. - : Elsevier BV. - 2405-8440. ; 9:4, s. e15200-
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Tidskriftsartikel (refereegranskat)abstract
- In Bangladesh, people primarily depend on on-site sanitation facilities (OSSF) with an immense challenge in achieving safe sanitation due to unplanned infrastructure development, improper management of fecal sludge, and inadequate monitoring. The commitment of attaining Sustain-able Development Goals (SDG) 6.2 (ensuring safe sanitation for all) by 2030 requires immediate attention in the management of fecal sludge for low-middle income countries. This paper pre-sented the findings, challenges, and possible ways forward from a study conducted to provide data for Information and Communication Technology (ICT)-based fecal sludge management (FSM) at a municipality in the northwest of Bangladesh. A total of 18,808 households and 407 institutions in Saidpur municipality, a non-sewered town in Nilphamari district, were studied to understand the type of containment structures and on-ground desludging practices. The study showed around 10% of containments were connected to the drains illegally, 95% of the people in Saidpur practiced unsafe disposal, and 7% still practiced open defecation. To identify these malpractices, the study also implemented an ICT-based sustainable solution through a web application that enabled the local administrator to have a global look at the sanitation scenario of the municipality. The dashboard was developed to create a total sanitation monitoring system, identify defaulters, allow target-based safe managed sanitation service strategies, and ensure sustainability in FSM. The study highlighted the accessibility of vacuum truck services projecting through a spatial map and identified methods to empty the septic tanks where Vacutag services are unavailable by engaging local pit emptiers. The innovative approach of fecal sludge man-agement will help not only to improve the existing sanitation practices but also raise community awareness to ensure sustainable sanitation system. Altogether, the web system will work as a medium to manage the faecal sludge for the existing co-compost plant where the faeces is con-verted into organic soil conditioner, creating prospects for a green business mechanism.
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| 4. |
- Taqvi, Syed Ali Ammar, et al.
(författare)
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Simultaneous fault diagnosis based on multiple kernel support vector machine in nonlinear dynamic distillation column
- 2022
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Ingår i: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 10:3, s. 814-839
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Tidskriftsartikel (refereegranskat)abstract
- Although numerous works have been done, most of the studies in fault diagnosis are limited to single fault type at a time. Majority of the works reported in the literature do not extend the diagnosis of the root cause of the fault for simultaneous faults specifically in the distillation column. However, an industrial system is susceptible to more than one fault at a time, which may or may not be interrelated. These faults not only reduce the diagnosis performance but also increase the computational complexity of the diagnosis algorithm. In this work, therefore, a multiple kernel support vector machine (MK-SVM) algorithm is proposed to diagnose simultaneous faults in the distillation column. In the developed MK-SVM algorithm, multilabel approach based on various kernel functions has been utilized for the classification of simultaneous faults. Dynamic simulation of a pilot-scale distillation column using Aspen Plus(R) is used for generating data in normal and faulty operation. Eight different fault types are considered, including valve sticking at reflux and reboiler, tray upsets, loss of feed flow, feed composition, and feed temperature changes. In the classification of simultaneous faults, a combination of two, three, and four faults is introduced for the performance evaluation of the proposed MK-SVM algorithm. The result showed that the proposed MK-SVM has a high fault detection rate (FDR) of 99.51% and a very low misclassification rate (MR) of 0.49%. The MK-SVM-based classification is better with the F1 score of >97% for all combinations of faults. Moreover, it is observed that the proposed MK-SVM shows better fault diagnosis for single, multiple, and simultaneous faults as compared to other established machine-learning algorithms.
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| 5. |
- Ul Haq, Sheikh Ehsan, et al.
(författare)
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Multistage carbon dioxide compressor efficiency enhancement using waste heat powered absorption chillers
- 2021
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Ingår i: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 9:9, s. 1373-1384
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Tidskriftsartikel (refereegranskat)abstract
- The performance of a multistage centrifugal compressor is highly influenced by the ambient conditions, especially during the summer seasons; their capacity shrinks and thus the power requirement for compression will increase. The prime cause of these constraints is the interstage cooling limitations. This study simulates various suction conditions of a multistage compressor on Aspen HYSYS (R) and suggests its debottlenecking by making the suction temperatures comparable to winter seasons. This is achieved by installing an additional exchanger at the downstream of each interstage cooler, cooling down the gas further by using absorption refrigeration chillers. These chillers are powered up by the waste heat recovered from the exhaust steam coming from the prime mover, steam turbine, of the same compressor. This modification will save a considerable amount of power (663 kW), net savings (Gross Savings - OPEX: 72 289 $/y), and reduce the carbon footprint (954 ton/y) of the overall process.
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