Records Added in July 2020
Records added in July 2020
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Showing records 1 to 25 of 140. [First] Page: 1 2 3 4 5 Last
Design and Eco-techno-economic Analyses of SOFC/GT Hybrid Systems Accounting for Long-term Degradation Effects
Haoxiang Lai, Nor Farida Harun, David Tucker, Thomas Adams II
November 24, 2020 (v2)
Models and codes that were used in this work. Please read the simulation instruction.
Comparison of Steel Manufacturing Off-Gas Utilization Methods via Life Cycle Analysis
July 31, 2020 (v1)
Subject: Other
Keywords: blast furnace gas, coke oven gas, combined cycle power plant, Life Cycle Analysis, methanol production
This study utilizes life cycle analysis to compare three steel manufacturing off-gas utilization systems: a status quo system, which produces electricity via a low-pressure steam turbine; a combined cycle power plant (CCPP) system, which produces electricity using gas and steam turbines; and a methanol (MeOH) system, which converts coke oven gas (COG) and blast furnace gas (BFG) into MeOH (CBMeOH). This research seeks to compare the environmental impacts of each system based on equivalent raw material inputs. Since the systems have different products, system expansion is used to ensure that they have the same outputs and are therefore comparable. The system boundary consists of a combination of cradle-to-gate and gate-to-gate boundaries. The environmental effects of each system are compared at five locations—Ontario, the USA, Finland, Mexico, and China—using TRACI, CML-IA baseline, ReCiPe2016, and IMPACT2002+ in SimaPro v9. The results show that in Ontario, Finland, and China, CBMeOH s... [more]
Supply Chain Monitoring Using Principal Component Analysis
Jing Wang, Christopher Swartz, Brandon Corbett, Kai Huang
July 16, 2020 (v1)
Keywords: monitoring, Multivariate Statistics, Supply Chain
Various types of risks exist in a supply chain, and disruptions could lead to economic loss or even breakdown of a supply chain without an effective mitigation strategy. The ability to detect disruptions early can help improve the resilience of the supply chain. In this paper, the application of principal component analysis (PCA) and dynamic PCA (DPCA) in fault detection and diagnosis of a supply chain system is investigated. In order to monitor the supply chain, data such as inventory levels, market demands and amount of products in transit are collected. PCA and DPCA are used to model the normal operating conditions (NOC). Two monitoring statistics, the Hotelling's T-squared and the squared prediction error (SPE), are used to detect abnormal operation of the supply chain. The confidence limits of these two statistics are estimated from the training data based on the $\chi^2$- distributions. The contribution plots are used to identify the variables with abnormal behavior when at le... [more]
MobileNetV2 Ensemble for Cervical Precancerous Lesions Classification
Cătălin Buiu, Vlad-Rareş Dănăilă, Cristina Nicoleta Răduţă
July 17, 2020 (v1)
Keywords: biomedical image processing, cervical cancer, computer-aided diagnosis, deep learning, ensemble, machine learning algorithms, MobileNetV2, transfer learning
Women’s cancers remain a major challenge for many health systems. Between 1991 and 2017, the death rate for all major cancers fell continuously in the United States, excluding uterine cervix and uterine corpus cancers. Together with HPV (Human Papillomavirus) testing and cytology, colposcopy has played a central role in cervical cancer screening. This medical procedure allows physicians to view the cervix at a magnification of up to 10%. This paper presents an automated colposcopy image analysis framework for the classification of precancerous and cancerous lesions of the uterine cervix. This framework is based on an ensemble of MobileNetV2 networks. Our experimental results show that this method achieves accuracies of 83.33% and 91.66% on the four-class and binary classification tasks, respectively. These results are promising for the future use of automatic classification methods based on deep learning as tools to support medical doctors.
Graphene-Based Hydrogen Gas Sensors: A Review
Anna Ilnicka, Jerzy P. Lukaszewicz
July 17, 2020 (v1)
Keywords: functionalized graphene, gas sensor, graphene, graphene oxide, hydrogen sensor, metal, metal oxide, polymer, reduced graphene oxide, semiconductor
Graphene is a material gaining attention as a candidate for new application fields such as chemical sensing. In this review, we discuss recent advancements in the field of hydrogen gas sensors based on graphene. Accordingly, the main part of the paper focuses on hydrogen gas sensors and examines the influence of different manufacturing scenarios on the applicability of graphene and its derivatives as key components of sensing layers. An overview of pristine graphene customization methods is presented such as heteroatom doping, insertion of metal/metal oxide nanosized domains, as well as creation of graphene-polymer blends. Volumetric structuring of graphene sheets (single layered and stacked forms) is also considered as an important modifier of its effective use. Finally, a discussion of the possible advantages and weaknesses of graphene as sensing material for hydrogen detection is provided.
Experimental and Statistical Validation of Data on Mesh-Coupled Annular Distributor Design for Swirling Fluidized Beds
Shazia Shukrullah, Muhammad Yasin Naz, Abdul Ghaffar, Yasin Khan, Abdulrehman Ali Al-Arainy, Rashed Meer
July 17, 2020 (v1)
Keywords: annular distributor, NCSS software, particle image velocimetry, statistical analysis, swirling fluidized bed
In this study, velocimetry and statistical analyses were conducted on a swirling fluidized bed. A bed of spherical particles (4 mm) was fluidized by using an annular distributor covered with mesh. The angles of rectangular blades in the distributor were set at 30°, 45°, 60°, 75° and 90°, and the cell size of the mesh cover was 2.5 × 2.5 mm2. The weight was varied from 500 to 1250 g and the effect of each variable on bed velocity response was quantified through velocimetry and statistical analysis. The statistical analysis was conducted using NCSS statistical software. The blade angle, bed weight and superficial velocity for 4 mm particles were statistically optimized at 750 g, 58.26° and 1.45 m/s, respectively. On the experimental side, these parameters have been optimized at 750 g, 60° and 1.41 m/s, respectively. A small difference of 1.74° was noticed in experimental and statistical predictions for the blade angle. The bed weights and superficial velocities were found to be same in b... [more]
Industrial Processes Management for a Sustainable Society: Global Research Analysis
Emilio Abad-Segura, Manuel E. Morales, Francisco Joaquín Cortés-García, Luis Jesús Belmonte-Ureña
July 17, 2020 (v1)
Keywords: effective management, green technology, industry, scientific research, sustainable process, sustainable society
Few decades ago, the development of the industrial sector was disconnected from society’s protection. Negative effects awareness emerges from the current industrial processes through the Sustainable Development Goals (SDGs), considering the causal implications to build up a more sustainable society. The aim of this study is to analyze the state of the art in industrial processes management to obtain positive and sustainable effects on society. Thus, a bibliometric analysis of 1911 articles was set up during the 1988−2019 period, bringing up the authors’ productivity indicators in the scientific field, that is, journals, authors, research institutions, and countries. We have identified environmental management; the impact assessments of industrial processes on the environment and its relation with a more sustainable society; as well as the study of the sustainable management of water resources as the related axes in the study of environmental protection with political, economic, and edu... [more]
Greening the Gas Grid—Evaluation of the Biomethane Injection Potential from Agricultural Residues in Austria
Bernhard Stürmer
July 17, 2020 (v1)
Subject: Energy Policy
Keywords: agricultural residues, biogas, biomethane potential, green gas
In order to implement the Paris Climate Agreement, the current Austrian coalition government has included trend-setting targets in its policy statement. “Green gas” plays a key role in this context, as the natural gas grid shall also gradually become renewable. This article analyses the technical biomethane injection potential for agricultural residues based on Integrated Administration and Control System (IACS) data on a municipal level. While a technical biogas potential of 16.2 TWhCH4 from catch crops, farm manure, straw and beet leaves is available, only about half of it can be fed into the gas grid because of technical and economic reasons. Austria’s biomethane injection potential of 7.4 TWhCH4 is mainly produced in arable farming regions. In order to further increase this potential, the investment costs of biogas upgrading plants must be reduced, the use of biogenic waste and energy crops must be further promoted and an investor-friendly legal framework must be created.
Improved Catalytic Properties of Thermomyces lanuginosus Lipase Immobilized onto Newly Fabricated Polydopamine-Functionalized Magnetic Fe3O4 Nanoparticles
Yanhong Bi, Zhaoyu Wang, Rui Zhang, Yihan Diao, Yaoqi Tian, Zhengyu Jin
July 17, 2020 (v1)
Subject: Biosystems
Keywords: immobilization, magnetic nanoparticle, stability, Thermomyces lanuginosus lipase
In this study, magnetic Fe3O4 nanoparticles coated with polydopamine possessing abundant amino groups (Fe3O4@PDA) were conveniently prepared, detailed, and characterized, and then firstly used as a supporting matrix for immobilizing Thermomyces lanuginosus lipase (Fe3O4@PDA@TLL). The effects of some crucial factors on the immobilization efficiency were investigated and the optimal protein loading and activity recovery were found to be 156.4 mg/g and 90.9%, respectively. Characterization studies revealed that Fe3O4@PDA@TLL displayed a broader pH and temperature adaptability as compared to the free TLL, which allows its use at wider ranges of reaction conditions. With regard to the stabilities, the immobilized TLL clearly displayed improved pH, thermal, and solvent tolerance stabilities compared to the free enzyme, suggesting that the biocompatible Fe3O4@PDA might be an outstanding material for immobilizing TLL and acting as alternative support for different enzymes.
Organoboron Ionic Liquids as Extractants for Distillation Process of Binary Ethanol + Water Mixtures
Ilsiya M. Davletbaeva, Alexander V. Klinov, Alina R. Khairullina, Alexander V. Malygin, Sergey E. Dulmaev, Alisa R. Davletbaeva, Timur A. Mukhametzyanov
July 17, 2020 (v1)
Keywords: aqueous solution, Extraction, ionic liquids, physicochemical properties, vapor–liquid equilibrium
Aminoethers of boric acid, which are organoboron ionic liquids, were synthesized by using boric acid, triethanolamine, and triethylene glycol/diethylene glycol. Due to the formation of intermolecular complexes of borates, the structure of aminoethers of boric acid contains ion pairs separated in space, giving these compounds the properties inherent to ionic liquids. It is established that the thermal stability of aminoethers under normal atmospheric conditions increases with an increase in the size of the glycol. According to measurements of fast scanning calorimetry, density, dynamic viscosity, and electrical conductivity, water is involved in the structural organization of aminoethers of boric acid. The impact of the most thermostable organoboron ionic liquids on the phase equilibrium conditions of the vapor−liquid azeotropic ethanol−water mixture is studied. It is shown that the presence of these substances leads to increase in the relative volatility of ethanol. In general, the mag... [more]
Spark Plasma Sintering of Cobalt Powders in Conjunction with High Energy Mechanical Treatment and Nanomodification
Van Minh Nguyen, Rita Khanna, Yuri Konyukhov, Tien Hiep Nguyen, Igor Burmistrov, Vera Levina, Ilya Golov, Gopalu Karunakaran
July 17, 2020 (v1)
Subject: Materials
Keywords: densification, mechanical processing, mechanical properties, nanomodification, spark plasma sintering
Spark plasma sintering (SPS) investigations were carried out on three sets of Co specimens: untreated, high energy mechanically (HEMT) pre-treated, and nanomodified powders. The microstructure, density, and mechanical properties of sintered pellets were investigated as a function of various pre-treatments and sintering temperatures (700−1000 °C). Fine-grained sinters were obtained for pre-treated Co powders; nano-additives tended to inhibit grain growth by reinforcing particles at grain boundaries and limiting grain-boundary movement. High degree of compaction was also achieved with relative densities of sintered Co pellets ranging between 95.2% and 99.6%. A direct co-relation was observed between the mechanical properties and densities of sintered Co pellets. For a comparable sinter quality, sintering temperatures for pre-treated powders were lower by 100 °C as compared to untreated powders. Highest values of bending strength (1997 MPa), microhardness (305 MPa), and relative density (... [more]
Environmental Assessment of Olive Mill Solid Waste Valorization via Anaerobic Digestion Versus Olive Pomace Oil Extraction
Bernabé Alonso-Fariñas, Armando Oliva, Mónica Rodríguez-Galán, Giovanni Esposito, Juan Francisco García-Martín, Guillermo Rodríguez-Gutiérrez, Antonio Serrano, Fernando G. Fermoso
July 17, 2020 (v1)
Keywords: biogas, environmental impact, life cycle assessment, olive pomace, Renewable and Sustainable Energy
Anaerobic digestion is a promising alternative to valorize agrifood wastes, which is gaining interest under an environmental sustainability overview. The present research aimed to compare anaerobic digestion with olive pomace oil extraction, by using life cycle assessment, as alternatives for the valorization of the olive mill solid waste generated in the centrifugation process with a two-outlet decanter from oil mills. In the case of olive pomace oil extraction, two cases were defined depending on the type of fuel used for drying the wet pomace before the extraction: natural gas or a fraction of the generated extracted pomace. The anaerobic digestion alternative consisted of the production of biogas from the olive mill solid waste, heat and electricity cogeneration by the combustion of the generated biogas, and composting of the anaerobic digestate. The life cycle assessment showed that anaerobic digestion was the best alternative, with a global environmental impact reduction of 88.1... [more]
Improvement of the Mechanical Properties of Thermosetting-Binding-System-Based Composites by Means of Kneading Procedure Modification and Composite Formulation
Adis Šahinović, Branka Mušič
July 17, 2020 (v1)
Subject: Materials
Keywords: composite material, kneading procedure, mechanical properties, polymer molding compound, process optimization, rheology, thermomechanical analysis, thermosetting resin
By understanding the effects of the physical properties of individual input materials (e.g., binding system) on the physical and thermal properties of a composite material, the latter can be engineered in advance according to the desired properties and application. Often, a need to replace a specific component in a composite material arises, due to various reasons such as high raw material prices, product price reduction, environmental issues, improvement of properties, and others. In this study, we focused on the substitution of a phenolic novolac resin binding system and the reduction of compounding process temperature in combination with material throughput and screw speed variation of a phenolic-novolac-resin-based composite material, manufactured by kneading process using a co-kneader single screw extruder. Modifications were carried out in the interest of reducing production process cost and positive environmental effect due to reduction of energy consumption in the compounding p... [more]
Bacterial Cellulose as a Versatile Platform for Research and Development of Biomedical Materials
Selestina Gorgieva
July 17, 2020 (v1)
Subject: Biosystems
Keywords: antimicrobial, bacterial cellulose, biocompatibility, biomedical application, drug delivery, medical device, scaffolds, wound dressings
The unique pool of features found in intracellular and extracellular bacterial biopolymers attracts a lot of research, with bacterial cellulose (BC) being one of the most versatile and common. BC is an exopolysaccharide consisting solely of cellulose, and the variation in the production process can vary its shape or even its composition when compounding is applied in situ. Together with ex situ modification pathways, including specialised polymers, particles or exclusively functional groups, BC provides a robust platform that yields complex multifunctional compounds that go far beyond ultra-high purity, intrinsic hydrophilicity, mechanical strength and biocompatibility to introduce bioactive, (pH, thermal, electro) responsive, conductive and ‘smart’ properties. This review summarises the research outcomes in BC-medical applications, focusing mainly on data from the past decade (i.e., 2010−2020), with special emphasis on BC nanocomposites as materials and devices applicable in medicine.... [more]
Performance Evaluation of Elimination of Stagnation of Solar Thermal Systems
Miroslav Rimar, Marcel Fedak, Jakub Vahovsky, Andrii Kulikov, Peter Oravec, Olha Kulikova, Michal Smajda, Miroslav Kana
July 17, 2020 (v1)
Keywords: energy performance, stagnation, thermal collector
The study deals with the possibility of elimination of stagnation of thermal systems. The state of stagnation of thermal systems leads to overheating and evaporation of the heat transfer medium, which increases pressure and can lead to damage to the solar thermal system. Stagnation can occur due to a fault and stopping of the circulation pump, which causes the circulation of the heat transfer medium to stop. Another possibility is to achieve thermal saturation in the system, which can be affected by low heat consumption from the system. Elimination of stagnation is possible by various construction designs of collectors or by using other technical means. This study describes an experiment verifying the usability of a thermal collector’s tilting system to eliminate thermal stagnation of the system. The system is fully automatic, and when recording the limit values, ensures that the panel is rotated out of the ideal position, thus reducing the amount of received energy. In this way, the t... [more]
Assessment of the SM12, SM8, and SMD Solvation Models for Predicting Limiting Activity Coefficients at 298.15 K
Sydnee N. Roese, Justin D. Heintz, Cole B. Uzat, Alexa J. Schmidt, Griffin V. Margulis, Spencer J. Sabatino, Andrew S. Paluch
July 17, 2020 (v1)
Keywords: electronic structure calculation, infinite dilution activity coefficient, limiting activity coefficient, solvation free energy
The SMx (x = 12, 8, or D) universal solvent models are implicit solvent models which using electronic structure calculations can compute solvation free energies at 298.15 K. While solvation free energy is an important thermophysical property, within the thermodynamic modeling of phase equilibrium, limiting (or infinite dilution) activity coefficients are preferred since they may be used to parameterize excess Gibbs free energy models to model phase equilibrium. Conveniently, the two quantities are related. Therefore the present study was performed to assess the ability to use the SMx universal solvent models to predict limiting activity coefficients. Two methods of calculating the limiting activity coefficient where compared: (1) the solvation free energy and self-solvation free energy were both predicted and (2) the self-solvation free energy was computed using readily available vapor pressure data. Overall the first method is preferred as it results in a cancellation of errors, speci... [more]
Assessment and Prediction of Complex Industrial Steam Network Operation by Combined Thermo-Hydrodynamic Modeling
Kristián Hanus, Miroslav Variny, Peter Illés
July 17, 2020 (v1)
Keywords: bottleneck, cold spot, heat losses, operation optimization, steam network
Steam network operation stability and reliability is vital for any industrial branch. A combined steam network model comprising a balance and a coupled thermo-hydrodynamic model, including seasonal variations impact and system specificities, is presented. A balance model can readily be used by a refinery’s operators. The thermo-hydrodynamic model identifies system bottlenecks and cold spots and evaluates proposed operation and investment measures including heat loss reduction. A three-pressure levels refinery steam network served for model testing and validation. Balance model results reveal significant misbalance in steam production and consumption, reaching 30.5% in the low-pressure steam system, and heat balance differences in the range of 9.2% to 29.5% on individual pressure levels, attributable both to flow measurement accuracy issues and to heat losses. The thermo-hydrodynamic model results differ from the measured steam parameters by less than 5% (temperature) and by less than 4... [more]
TLC-Densitometric Determination of Five Coxibs in Pharmaceutical Preparations
Paweł Gumułka, Monika Dąbrowska, Małgorzata Starek
July 17, 2020 (v1)
Subject: Biosystems
Keywords: coxibs, human and veterinary drugs, TLC-densitometry, validation of the method
A class of drugs called coxibs (COX-2 inhibitors) were created to help relieve pain and inflammation of osteoarthritis and rheumatoid arthritis with the lowest amount of side effects possible. The presented paper describes a new developed, optimized and validated thin layer chromatographic (TLC)-densitometric procedure for the simultaneous assay of five coxibs: celecoxib, etoricoxib, firecoxib, rofecoxib and cimicoxib. Chromatographic separation was conducted on HPTLC F254 silica gel chromatographic plates as a stationary phase using chloroform−acetone−toluene (12:5:2, v/v/v) as a mobile phase. Densitometric detection was carried out at two wavelengths of 254 and 290 nm. The method was tested according to ICH guidelines for linearity, recovery and specificity. The presented method was linear in a wide range of concentrations for all analyzed compounds, with correlation coefficients greater than 0.99. The method is specific, precise (%RSD < 1) and accurate (more than 95%, %RSD < 2... [more]
An Adjective Selection Personality Assessment Method Using Gradient Boosting Machine Learning
Bruno Fernandes, Alfonso González-Briones, Paulo Novais, Miguel Calafate, Cesar Analide, José Neves
July 17, 2020 (v1)
Keywords: Affective Computing, gradient boosting, Machine Learning, personality assessment
Goldberg’s 100 Unipolar Markers remains one of the most popular ways to measure personality traits, in particular, the Big Five. An important reduction was later preformed by Saucier, using a sub-set of 40 markers. Both assessments are performed by presenting a set of markers, or adjectives, to the subject, requesting him to quantify each marker using a 9-point rating scale. Consequently, the goal of this study is to conduct experiments and propose a shorter alternative where the subject is only required to identify which adjectives describe him the most. Hence, a web platform was developed for data collection, requesting subjects to rate each adjective and select those describing him the most. Based on a Gradient Boosting approach, two distinct Machine Learning architectures were conceived, tuned and evaluated. The first makes use of regressors to provide an exact score of the Big Five while the second uses classifiers to provide a binned output. As input, both receive the one-hot enc... [more]
High Enzymatic Recovery and Purification of Xylooligosaccharides from Empty Fruit Bunch via Nanofiltration
Hans Wijaya, Kengo Sasaki, Prihardi Kahar, Nanik Rahmani, Euis Hermiati, Yopi Yopi, Chiaki Ogino, Bambang Prasetya, Akihiko Kondo
July 17, 2020 (v1)
Keywords: empty fruit bunch, endoxylanase, membrane technology, xylooligosaccharides, xylose
Xylooligosaccharides (XOS) are attracting an ever-increasing amount of interest for use as food prebiotics. In this study, we used efficient membrane separation technology to convert lignocellulosic materials into a renewable source of XOS. This study revealed a dual function of nanofiltration membranes by first achieving a high yield of xylobiose (a main component of XOS) from alkali-pretreated empty fruit bunch (EFB) hydrolysate, and then by achieving a high degree of separation for xylose as a monosaccharide product. Alkali pretreatment could increase the xylan content retention of raw EFB from 23.4% to 26.9%, which eventually contributed to higher yields of both xylobiose and xylose. Nanofiltration increased the total amount of XYN10Ks_480 endoxylanase produced from recombinant Streptomyces lividans 1326 without altering its specific activity. Concentrated XYN10Ks_480 endoxylanase was applied to the recovery of both xylobiose and xylose from alkali-pretreated EFB hydrolysate. Xylob... [more]
A Comparison of Bioactive Glass Scaffolds Fabricated ‎by Robocasting from Powders Made by Sol−Gel and Melt-Quenching Methods
Basam A. E. Ben-Arfa, Robert C. Pullar
July 17, 2020 (v1)
Subject: Biosystems
Keywords: 45S5 Bioglass®, bioactive glass, biomaterials, biomedical implants, robocasting, scaffold, sol–gel
Bioactive glass scaffolds are used in bone and tissue biomedical implants, and there is great interest in their fabrication by additive manufacturing/3D printing techniques, such as robocasting. Scaffolds need to be macroporous with voids ≥100 m to allow cell growth and vascularization, biocompatible and bioactive, with mechanical properties matching the host tissue (cancellous bone for bone implants), and able to dissolve/resorb over time. Most bioactive glasses are based on silica to form the glass network, with calcium and phosphorous content for new bone growth, and a glass modifier such as sodium, the best known being 45S5 Bioglass®. 45S5 scaffolds were first robocast in 2013 from melt-quenched glass powder. Sol−gel-synthesized bioactive glasses have potential advantages over melt-produced glasses (e.g., greater porosity and bioactivity), but until recently were never robocast as scaffolds, due to inherent problems, until 2019 when high-silica-content sol−gel bioactive glasses (H... [more]
Robust Design of PC/ABS Filled with Nano Carbon Black for Electromagnetic Shielding Effectiveness and Surface Resistivity
Wipoo Sriseubsai, Arsarin Tippayakraisorn, Jun Wei Lim
July 17, 2020 (v1)
Subject: Materials
Keywords: carbon black, dissipation of electrostatic discharge, electromagnetic shielding effectiveness, PC/ABS, surface resistivity
This study focuses on the electromagnetic interference shielding effectiveness (EMI SE), dissipation of electrostatic discharge (ESD), and surface resistivity of polymer blends between polycarbonate (PC) and acrylonitrile−butadiene−styrene (ABS) filled with carbon black powder (CBp) and carbon black masterbatch (CBm). The mixtures of PC/ABS/CB composites were prepared by the injection molding for the 4-mm thickness of the specimen. The D-optimal mixture design was applied in this experiment. The EMI SE was measured at the frequency of 800 and 900 MHz with a network analyzer, MIL-STD-285. The result showed that the EMI SE was increased when the amount of filler increased. The surface resistivity of the composites was determined according to the ASTM D257. It was found that the surface resistivity of the plastic with no additives was 1012 Ω/ square. When the amount of fillers was added, the surface resistivity of plastic composites decreased to the range of 106−1011 Ω/square, which was s... [more]
A Data-Driven-Based Industrial Refrigeration Optimization Method Considering Demand Forecasting
Josep Cirera, Jesus A. Carino, Daniel Zurita, Juan A. Ortega
July 17, 2020 (v1)
Keywords: Compressors, data-driven, Energy Efficiency, industrial process modelling, multi-layer perceptron, partial load ratio, refrigeration systems, self-organizing maps
One of the main concerns of industry is energy efficiency, in which the paradigm of Industry 4.0 opens new possibilities by facing optimization approaches using data-driven methodologies. In this regard, increasing the efficiency of industrial refrigeration systems is an important challenge, since this type of process consume a huge amount of electricity that can be reduced with an optimal compressor configuration. In this paper, a novel data-driven methodology is presented, which employs self-organizing maps (SOM) and multi-layer perceptron (MLP) to deal with the (PLR) issue of refrigeration systems. The proposed methodology takes into account the variables that influence the system performance to develop a discrete model of the operating conditions. The aforementioned model is used to find the best PLR of the compressors for each operating condition of the system. Furthermore, to overcome the limitations of the historical performance, various scenarios are artificially created to fin... [more]
The Effect of Variations of Flow from Tributary Channel on the Flow Behavior in a T-Shape Confluence
Aliasghar Azma, Yongxiang Zhang
July 17, 2020 (v1)
Keywords: channel confluence, the separation zone, turbulent structure
Channel confluences are of the common structures in fluid transport channels. In this study, a series of numerical simulations were performed, utilizing a 3D code to investigate the reaction of the flow parameters and vortical structure to the variations in flow discharge and its Froude number from both main channel and tributary branch in a T-shape junction. The code was calibrated with the experimental data. Parameters, including the velocity, the turbulence energy, stream surface profile, head losses, and the transverse flow motions, were considered in different situations. It was concluded that increasing the ratio of discharge of flow from side-channel to the main channel (Q*) increased the area and power of the recirculation zone, as well as the width of separation plate downstream of the confluence, while it reduced the area of the stagnation zone (or the wake vortex) within the side-channel. It was also indicated that increasing the discharge ratio from side-channel resulted in... [more]
MOF-Based Adsorbents for Atmospheric Emission Control: A Review
Nicola Gargiulo, Antonio Peluso, Domenico Caputo
July 17, 2020 (v1)
Subject: Materials
Keywords: Adsorption, atmospheric environment, climate change, greenhouse gases, metal–organic frameworks
This review focuses on the use of metal−organic frameworks (MOFs) for adsorbing gas species that are known to weaken the thermal self-regulation capacities of Earth’s atmosphere. A large section is dedicated to the adsorption of carbon dioxide, while another section is dedicated to the adsorption of other different gas typologies, whose emissions, for various reasons, represent a “wound” for Earth’s atmosphere. High emphasis is given to MOFs that have moved enough ahead in their development process to be currently considered as potentially usable in “real-world” (i.e., out-of-lab) adsorption processes. As a result, there is strong evidence of a wide gap between laboratory results and the industrial implementation of MOF-based adsorbents. Indeed, when a MOF that performs well in a specific process is commercially available in large quantities, economic observations still make designers tend toward more traditional adsorbents. Moreover, there are cases in which a specific MOF remarkably... [more]
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