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Records Added in July 2020
Records added in July 2020
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Showing records 126 to 140 of 140. [First] Page: 2 3 4 5 6 Last
The Impact of Uncertainty Factors on the Decision-Making Process of Logistics Management
Łukasz Marzantowicz
July 2, 2020 (v1)
Keywords: conditions of uncertainty, logistic decisions, logistics management
The article is a contribution to the discussion on the possibilities of effective logistic decisions under the conditions of uncertainty. Variable and unpredictable factors, which create the conditions of uncertainty, not only directly affect logistic processes (positive or negative impact), but can also be a determinant of making decisions. Logistics management, because it is referred to in the context of decision-making, is currently defined by the quality of management decisions taken, including factors which often constitute only partially quantifiable sets. The main goal of the article is to show the strength of the dependence between the occurrence of uncertainty factors and the type of decision. On the basis of decision-making theory, the types of decisions were defined, and then a set of factors that are most important for a given type of decision was selected. The results of the analysis allowed the strength of the influence of uncertainty factors on making logistics decisions... [more]
Energetic Valorisation of Olive Biomass: Olive-Tree Pruning, Olive Stones and Pomaces
Juan Francisco García Martín, Manuel Cuevas, Chao-Hui Feng, Paloma Álvarez Mateos, Miguel Torres García, Sebastián Sánchez
July 2, 2020 (v1)
Keywords: bioethanol, combustion, gasification, olive, olive oils, olive pomaces, olive stones, olive-pruning debris, pyrolysis
Olive oil industry is one of the most important industries in the world. Currently, the land devoted to olive-tree cultivation around the world is ca. 11 × 106 ha, which produces more than 20 × 106 t olives per year. Most of these olives are destined to the production of olive oils. The main by-products of the olive oil industry are olive-pruning debris, olive stones and different pomaces. In cultures with traditional and intensive typologies, one single ha of olive grove annually generates more than 5 t of these by-products. The disposal of these by-products in the field can led to environmental problems. Notwithstanding, these by-products (biomasses) have a huge potential as source of energy. The objective of this paper is to comprehensively review the latest advances focused on energy production from olive-pruning debris, olive stones and pomaces, including processes such as combustion, gasification and pyrolysis, and the production of biofuels such as bioethanol and biodiesel. Futu... [more]
Water Droplets Translocation and Fission in a 3D Bi-Planar Multifurcated T-Junction Microchannels
Inn-Leon Lu, Voon-Loong Wong, Jit-Kai Chin, Kuzilati Kushaari
July 2, 2020 (v1)
Keywords: 3D multifurcated microchannels, droplet fission, emulsions, microfluidics, Newtonian, two-phase flow
Droplet fission has gained notable interest in drug delivery applications due to its ability to perform parallel operations in single device. Hitherto, droplet flow behavior in a 3D constriction was scarcely investigated. This study aims to investigate droplets fission inside a 3D bi-planar multifurcated microfluidic device. The flow behavior and droplet size distribution were studied in trifurcated microchannels using distilled water as dispersed phase (1 mPa·s) and olive oil (68 mPa·s) as continuous phase. Various sizes of subordinate daughter droplets were manipulated passively through the modulation of flowrate ratio (Q) (0.15 < Q < 3.33). Overall, we found droplet size coefficient of variations (CV%) ranging from 0.72% to 69%. Highly monodispersed droplets were formed at the upstream T-junction (CV% < 2%) while the droplet fission process was unstable at higher flowrate ratio (Q > 0.4) as they travel downstream (1.5% < CV% < 69%) to splitting junctions. Complex respons... [more]
Drying Characteristics of Dracocephalum moldavica Leaves: Drying Kinetics and Physicochemical Properties
Stanisław Rudy, Dariusz Dziki, Beata Biernacka, Andrzej Krzykowski, Mariusz Rudy, Urszula Gawlik-Dziki, Magdalena Kachel
July 2, 2020 (v1)
Keywords: antioxidant capacity, color changes, drying, essential oils, flavonoids content, Moldavian dragonhead
The aim of the study was to determine the effect of the method and temperature of the sublimation, vacuum and convective drying process on the kinetics of dehydration of the Moldovan dragonhead leaves, as well as on the physical and chemical properties, such as color coordinates, total content of phenolic compounds, antioxidant capacity, total monomeric anthocyanins content, total flavonoids content and content of essential oils. It was shown that the kinetics of the sublimation and vacuum drying process are best described by the logarithmic and Page models. Sublimation and vacuum drying were characterized by comparable process times. An increase in drying temperature caused a decrease in the content of phenolic compounds and antioxidant activity of the dried material and a significant change in the composition of essential oils. The lowest brightness of the dried material and the lowest color saturation was found after sublimation drying at 20 °C. The highest dried material quality wa... [more]
Multi-Objective Optimization Applications in Chemical Process Engineering: Tutorial and Review
Gade Pandu Rangaiah, Zemin Feng, Andrew F. Hoadley
July 2, 2020 (v1)
Subject: Optimization
Keywords: chemical engineering, multi-objective optimization, multiple criteria, non-dominated solutions, optimization procedure, optimization software, optimization techniques, Pareto optimal front, Pareto ranking, process engineering
This tutorial and review of multi-objective optimization (MOO) gives a detailed explanation of the 5 steps to create, solve, and then select the optimum result. Unlike single-objective optimization, the fifth step of selection or ranking of solutions is often overlooked by the authors of papers dealing with MOO applications. It is necessary to undertake a multi-criteria analysis to choose the best solution. A review of the recent publications using MOO for chemical process engineering problems shows a doubling of publications between 2016 and 2019. MOO applications in the energy area have seen a steady increase of over 20% annually over the last 10 years. The three key methods for solving MOO problems are presented in detail, and an emerging area of surrogate-assisted MOO is also described. The objectives used in MOO trade off conflicting requirements of a chemical engineering problem; these include fundamental criteria such as reaction yield or selectivity; economics; energy requireme... [more]
Phytochemical Profile, Antioxidant and Antitumor Activities of Green Grape Juice
Mohamad Nasser, Hoda Cheikh-Ali, Akram Hijazi, Othmane Merah, Abd El-Ameer N. Al-Rekaby, Rana Awada
July 2, 2020 (v1)
Keywords: anti-proliferative, antioxidant, phytochemicals, pulmonary adenocarcinoma, unripe grape juice, verjuice
(1) Plants, due to their phytochemicals, have long been known for their pharmacological potential and medicinal value. Verjuice, the acidic juice of unripe green grape, is still poorly characterized in terms of its chemical composition and biological activities. (2) In this study, we characterized the chemical composition, antioxidant and antitumor potential of verjuice extract. Folin−Ciocalteu and aluminum chloride reagents were used to identify the total phenol and total flavonoid composition. Various conventional methods were used to quantify the alkaloids and tannins. DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay and Neutral Red assay were used to assess the antioxidant and antitumor activities, respectively. (3) We showed that the verjuice extract contains alkaloids, tannins, and a high quantity of total flavonoids and total phenols. Besides its antioxidant activity, verjuice significantly repressed human pulmonary adenocarcinoma (A549) cells’ viability in bot... [more]
Synthesis of Large-Scale Bio-Hydrogen Network Using Waste Gas from Landfill and Anaerobic Digestion: A P-Graph Approach
Sadaf Hemmati, M. Mostafa Elnegihi, Chee Hoong Lee, Darren Yu Lun Chong, Dominic C. Y. Foo, Bing Shen How, ChangKyoo Yoo
July 2, 2020 (v1)
Keywords: graph theoretic, hydrogen production, optimisation, Process Synthesis, Renewable and Sustainable Energy
Due to the expanding concern on cleaner production and sustainable development aspects, a technology shift is needed for the hydrogen production, which is commonly derived from natural gas. This work aims to synthesise a large-scale bio-hydrogen network in which its feedstock, i.e., bio-methane, is originated from landfill gas and palm oil mill effluent (POME). Landfill gas goes through a biogas upgrader where high-purity bio-methane is produced, while POME is converted to bio-methane using anaerobic digestor (AD). The generated bio-methane is then distributed to the corresponding hydrogen sink (e.g., oil refinery) through pipelines, and subsequently converted into hydrogen via steam methane reforming (SMR) process. In this work, P-graph framework is used to determine a supply network with minimum cost, while ensuring the hydrogen demands are satisfied. Two case studies in the West and East Coasts of Peninsular Malaysia are used to illustrate the feasibility of the proposed model. In C... [more]
Ozonation Pretreatment for Reduction of Landfill Leachate Fouling on Membranes: A Response Surface Methodology Analysis
Everton Gripa, Alyne M. Costa, Juacyara C. Campos, Fabiana V. da Fonseca
July 2, 2020 (v1)
Keywords: fouling, landfill leachate, Membranes, ozone, response surface methodology, wastewater treatment
Batch ozonation was performed to assess its efficacy as a pretreatment for reverse osmosis (RO) membranes for treating leachate with high concentrations of recalcitrant organic compounds. Leachate samples from two different landfills were collected and characterized. The modified fouling index (MFI) was used to estimate the fouling potential of raw and ozonized leachates. A response surface experimental design was applied to optimize operational pH and ozone dose. The results demonstrate that the best operational conditions are 1.5 g/L of O3 at pH 12.0 and 1.5 g/L of O3 at pH 9.0 for Landfills 1 and 2, which reduce MFI by 96.22% and 94.08%, respectively. Additionally, they show toxicity factor decays of 98.44% for Landfill 1 and 93.75% for Landfill 2. These results, along with the similar behavior shown by leachate samples from distinct landfills, suggest that ozonation is a promising technology to fit this kind of wastewater into the requirements of RO membranes, enabling their use in... [more]
Fabrication of Ultrathin MoS2 Nanosheets and Application on Adsorption of Organic Pollutants and Heavy Metals
Siyi Huang, Ziyun You, Yanting Jiang, Fuxiang Zhang, Kaiyang Liu, Yifan Liu, Xiaochen Chen, Yuancai Lv
July 2, 2020 (v1)
Subject: Materials
Keywords: Adsorption, liquid exfoliation, quenching, transition metal dichalcogenides
Owing to their peculiar structural characteristics and potential applications in various fields, the ultrathin MoS2 nanosheets, a typical two-dimensional material, have attracted numerous attentions. In this paper, a hybrid strategy with combination of quenching process and liquid-based exfoliation was employed to fabricate the ultrathin MoS2 nanosheets (MoS2 NS). The obtained MoS2 NS still maintained hexagonal phase (2H-MoS2) and exhibited evident thin layer-structure (1−2 layers) with inconspicuous wrinkle. Besides, the MoS2 NS dispersion showed excellent stability (over 60 days) and high concentration (0.65 ± 0.04 mg mL−1). The MoS2 NS dispersion also displayed evident optical properties, with two characteristic peaks at 615 and 670 nm, and could be quantitatively analyzed with the absorbance at 615 nm in the range of 0.01−0.5 mg mL−1. The adsorption experiments showed that the as-prepared MoS2 NS also exhibited remarkable adsorption performance on the dyes (344.8 and 123.5 mg g−1 o... [more]
Synthesis and Characterization of New Fluoro/Trifluoromethyl-Substituted Acylthiourea Derivatives with Promising Activity against Planktonic and Biofilm-Embedded Microbial Cells
Carmen Limban, Diana Camelia Nuta, Alexandru Vasile Missir, Roxana Roman, Miron Teodor Caproiu, Florea Dumitrascu, Lucia Pintilie, Amalia Stefaniu, Mariana Carmen Chifiriuc, Marcela Popa, Irina Zarafu, Andreea Letiția Arsene, Cristina Elena Dinu Pirvu, Denisa Ioana Udeanu, Ioana Raluca Papacocea
July 2, 2020 (v1)
Subject: Biosystems
Keywords: 13C-NMR, 1H-NMR, anti-biofilm activity, antimicrobial activity, antioxidant activity, benzamides, IR spectroscopy, thiourea derivatives
The aim of this study was preparation of new derivatives based on 2-((4-chlorophenoxy)methyl)-N-(arylcarbamothioyl)benzamide structure; the new compounds were characterized by IR, NMR (1H, 13C) spectroscopy, and elemental analysis. The obtained compounds were evaluated for their in vitro antimicrobial activity against planktonic and biofilm-embedded microbial cells (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans), by qualitative and quantitative assays. Some of the compounds revealed promising antibacterial and antifungal activities, with low minimum inhibitory concentration values between 0.15 and 2.5 mg/mL and minimal biofilm eradication concentrations of 0.019−2.5 mg/mL. To investigate the potential target of their antibacterial activity, in silico drug-likeness and molecular docking screenings on Staphylococcus aureus DNA gyrase were performed. The compound with the best antibacterial activity (1g) was docked into topoisomer... [more]
Hydrogen Production by Partial Oxidation Reforming of Methane over Ni Catalysts Supported on High and Low Surface Area Alumina and Zirconia
Anis Fakeeha, Ahmed A. Ibrahim, Hesham Aljuraywi, Yazeed Alqahtani, Ahmad Alkhodair, Suliman Alswaidan, Ahmed E. Abasaeed, Samsudeen O. Kasim, Sofiu Mahmud, Ahmed S. Al-Fatesh
July 2, 2020 (v1)
Keywords: Al2O3, calcination, partial oxidation, reforming of methane, supported nickel, ZrO2
The catalytic activity of the partial oxidation reforming reaction for hydrogen production over 10% Ni supported on high and low surface area alumina and zirconia was investigated. The reforming reactions, under atmospheric pressure, were performed with a feed molar ratio of CH4/O2 = 2.0. The reaction temperature was set to 450−650 °C. The catalytic activity, stability, and carbon formation were determined via TGA, TPO, Raman, and H2 yield. The catalysts were calcined at 600 and 800 °C. The catalysts were prepared via the wet-impregnation method. Various characterizations were conducted using BET, XRD, TPR, TGA, TPD, TPO, and Raman. The highest methane conversion (90%) and hydrogen yield (72%) were obtained at a 650 °C reaction temperature using Ni-Al-H-600, which also showed the highest stability for the ranges of the reaction temperatures investigated. Indeed, the time-on-stream for 7 h of the Ni-Al-H-600 catalyst displayed high activity and a stable profile when the reaction tempera... [more]
Dyeing of Innovative Bicomponent Filament Fabrics (PET/PTT) by Disperse Dyestuffs: Characterization and Optimization Process
Marwa Souissi, Ramzi Khiari, Wafa Haddar, Mounir Zaag, Nizar Meksi, Hatem Dhaouadi
July 2, 2020 (v1)
Keywords: bicomponent filaments, disperse dyes, dyeing, polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT)
PET/PTT bicomponent filaments yarn is produced by two polymers: the polyethylene terephthalate (PET) and the polytrimethylene terephtalate (PTT) extruded side by side. This yarn is known for its high mechanical properties in particular elasticity and elastic recovery. However, differences between physical and chemical properties of the two components make the dyeing step of this yarn complicated. The aim of this work is the development of a dyeing process for bicomponent filaments without altering their physical and chemical properties. Different techniques such as SEM, FTIR, and differential scanning calorimetry (DSC) were used to characterize the studied yarn. For dyeing, three different disperse dyes CI Disperse Red 167.1, CI Disperse Yellow 211, and CI Disperse Red 60 with different energy classes were studied. The influence of dyeing conditions in particular dyeing temperature, pH of dye bath, dyeing time, and carrier concentration in the dye bath was evaluated. Responses analyzed... [more]
Design and Evaluation of the Lab-Scale Shell and Tube Heat Exchanger (STHE) for Poultry Litter to Energy Production
Xuejun Qian, Yulai Yang, Seong W. Lee
July 2, 2020 (v1)
Keywords: analysis, design, electricity, Energy, hot water, poultry litter, shell tube heat exchanger, space heating, temperature change, trailer temperature
Poultry litter is one type of biomass and waste generated from the farming process. This study performed a performance and process analysis of poultry litter to energy using the lab-scale shell and tube heat exchanger (STHE) system along with a Stirling engine and a swirling fluidized bed combustor (SFBC). The effects of tube shape, flow direction, and water flow rates on water and trailer temperature changes were investigated during the poultry litter co-combustion process. Energy flow analysis and emissions were also studied. Results showed that the water outlet temperature of 62.8 ° C in the twisted tube was higher than the straight tube case (58.3 ° C ) after 130 min of the co-combustion process. It was found that the counter-current direction had higher water temperature changes, higher logarithmic mean temperature difference (LMTD), and higher trailer temperature changes than the co-current direction. A water flow rate of 4.54 L/min showed adequate heat absorption... [more]
Surface Modification of Bombyx mori Silk Fibroin Film via Thiol-ene Click Chemistry
Xiaoning Zhang, Jianwei Liang, Zhenyu Chen, Carrie Donley, Xiaolin Zhang, Guotao Cheng
July 2, 2020 (v1)
Subject: Materials
Keywords: Bombyx mori, silk fibroin film, surface modification, thiol-ene click chemistry
The purpose of this work is to develop a strategy for the surface modification of Bombyx mori silk fibroin (SF) film, via a thiol-ene click reaction, in order to expand its potential applicability. To achieve this goal, terminal thiol groups, from reduced glutathione, were introduced onto the surface of the SF film via a carbodiimide coupling reaction. These immobilized thiol groups act as robust crosslinkers and allow us to rapidly functionalize the surface with alkene group-containing molecules via ultraviolet (UV) light-initiated thiol-ene click chemistry. The X-ray photoelectron spectroscopy results specifically determined that alkene group-containing molecules and UV illumination are required for the thiol-ene click modification to take place on thiolated SF films. Fourier-transform infrared spectroscopy characterization of SF films indicated that the β-sheet conformation of SF was hampered throughout the modification process. Furthermore, it was found that the processes for thiol... [more]
Design and Eco-techno-economic Analyses of SOFC/Gas Turbine Hybrid Systems Accounting for Long-Term Degradation
Haoxiang Lai, David Tucker, Nor Farida Harun, Thomas Adams II
June 30, 2020 (v1)
Solid oxide fuel cells (SOFCs) are a promising next-generation technology for power production from fossil fuels. Because they convert chemical energy into electricity electrochemically, they are generally more efficient than combustion-based power plants due to the thermodynamic limitations of combustion cycles, and accordingly, have lower carbon intensities [1]. However, one of the main drawbacks of SOFCs (and SOFC stacks) is that they can degrade over time in a variety of ways, including accruing damage to the anode, cathode, interconnects, and other cell or stack components. SOFCs are most commonly used in “constant power” mode, in which the fuel flow rate and current density are increased over time to counteract the degradation effects and yield a constant power output. However, higher flow rates cause the degradation rates to grow even faster, resulting in a lifetime potentially as short as 1.5 years [2].

Recent research has found that by operating in “constant voltage” mode,... [more]
Showing records 126 to 140 of 140. [First] Page: 2 3 4 5 6 Last
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