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Records Added in May 2020
Records added in May 2020
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Showing records 102 to 126 of 126. [First] Page: 1 2 3 4 5 6 Last
Laser-Induced Ignition and Combustion of Individual Aluminum Particles Below 10 μm by Microscopic High-Speed Cinematography
Fengting Hou, Shengji Li, Yue Wang, Xuefeng Huang
May 8, 2020 (v1)
Keywords: combustion mechanism, individual aluminum, laser ignition, microscopic high-speed cinematography, submicron particle
Metal aluminum has been widely used as an ingredient in propellant, gunpowder and thermite, but there is less understanding of the combustion mechanism of aluminum particles from submicron to several microns in diameter. This paper proposes to experimentally investigate the ignition and combustion characteristics of individual aluminum particles below 10 μm. A specific in situ diagnostic experimental apparatus was first designed for directly observing the ignition and combustion behaviors of individual aluminum particles, with a submicrometer spatial resolution and a temporal resolution of tens of microseconds. Direct observation through microscopic high-speed cinematography demonstrated that, when heated by a continuous laser, individual aluminum particles thermally expanded, followed by shell rupture; the molten aluminum core overflowed and evaporated, leading to ignition and combustion. Further results showed that, when the laser power densities were gradually increased (5.88, 7.56... [more]
Recovery of Molybdenum, Chromium, Tungsten, Copper, Silver, and Zinc from Industrial Waste Waters Using Zero-Valent Iron and Tailored Beneficiation Processes
Daniel Vollprecht, Katharina Plessl, Simone Neuhold, Fritz Kittinger, Wolfgang Öfner, Peter Müller, Robert Mischitz, Klaus Philipp Sedlazeck
May 8, 2020 (v1)
Keywords: critical metal removal, Ferrodecont process, hydrometallurgy, industrial waste water, thermal treatment, zero-valent iron
Zero-valent iron (ZVI) has been used for water treatment for more than 160 years. However, passivation of its surface often constituted a problem which could only be tackled recently by the innovative Ferrodecont process using a fluidized bed reactor. In this study, pilot scale experiments for the removal of Mo, Cr, W, Cu, Ag and Zn from two industrial waste water samples and lab-scale experiments for the beneficiation of the abrasion products are presented to integrate the Ferrodecont process into a complete recycling process chain. Firstly, 38.5 % of Cu was removed from sample A, yielding abrasion products containing 33.1 wt% Cu as metallic copper (Cu) and various Cu compounds. The treatment of sample B removed 99.8 % of Mo, yielding abrasion products containing 17.8 wt% of Mo as amorphous phases or adsorbed species. Thermal treatment (1300 °C) of the abrasion product A indicated a reduction of delafossite to metallic Cu according to differential scanning calorimetry (DSC), thermogra... [more]
Numerical Simulation of Cavitation Performance in Engine Cooling Water Pump Based on a Corrected Cavitation Model
Wei Li, Enda Li, Weidong Shi, Weiqiang Li, Xiwei Xu
May 8, 2020 (v1)
Keywords: cavitation model, engine cooling water pump, numerical simulation, thermodynamic effect, unsteady process
To analyze the internal flow of the engine cooling water pump (ECWP) under thermodynamic effect, Zwart cavitation model based on the Rayleigh-Plesset equation is corrected, and NACA0015 hydrofoil was selected to verify the corrected model. The cavitation performances of ECWP with different temperatures were numerically simulated based on a corrected cavitation model. Research results show that simulation values of pressure distribution coefficient in hydrofoil surface at 70 °C are in closest agreement with experimental values when the evaporation and condensation coefficients are 10 and 0.002, respectively. With the decrease of absolute pressure in pump inlet, bubbles firstly occurred at the blade inlet side near the suction surface and then gradually extended to the pressure surface, finally clogged the impeller passage. Compared to the inlet section, the cavitation degree is much more serious close to the trailing edge. With the temperature increases, the cavitation in ECWP occurs in... [more]
Depigmented Centella asiatica Extraction by Pretreated with Supercritical Carbon Dioxide Fluid for Wound Healing Application
Warintorn Ruksiriwanich, Chiranan Khantham, Korawan Sringarm, Sarana Sommano, Pensak Jantrawut
May 8, 2020 (v1)
Subject: Biosystems
Keywords: angiogenesis, cell migration, Centella asiatica, depigmentation, supercritical carbon dioxide fluid extraction, wound healing
Centella asiatica has been included in Thai traditional medicinal plants and recipes, as a well-established historical use as a vegetable and tonic. However, when applied in modern formulations, the progressive degradation of the plant pigments occurs, causing color-fading and color variation in the products. Depigmentation of the comminuted sample using supercritical carbon dioxide (scCO2) fluid extraction with a cosolvent was introduced as a pretreatment to solve the color-fading problem. The contents of compounds with known biological activities and the wound healing activities (antioxidant screening by DPPH and ABTS+ scavenging activities; cell migration assay; matrix metallopeptidase [MMP]-2 inhibition on human skin fibroblast; endothelial cell tube formation assay) of the C. asiatica leaf extracts obtained by conventional ethanolic extraction (CV) and pretreatment using scCO2 extraction, were determined. Total triterpenoids (madecassoside, asiaticoside B, asiaticoside, madecassic... [more]
Biodrying of the Light Fraction from Anaerobic Digestion Pretreatment in Order to Increase the Total Recovery Rate
Isabella Pecorini, Donata Bacchi, Renato Iannelli
May 8, 2020 (v1)
Keywords: anaerobic digestion, biodrying, biostabilization, light fraction, municipal solid waste, pre-treatment, refuse-derived fuels
Two pilot-scale tests were carried out to assess if biodrying could be an effective process for the treatment of light fraction produced by an hydromechanical pre-treatment in an anaerobic digestion plant. The trials were performed using two pilot-scale stainless steel cylindrical reactors of 750 L capacity. Two tests were performed: in Test 1, only the light fraction was used; in Test 2, the light fraction was mixed with a bulking agent composed of garden and pruning waste. In Test 2, the highest temperature (71 °C) in a short time (8 days) was reached. An average water content reduction of 78% in Test 1 and 61% in Test 2 was measured, leading to similar reductions of weight (47−48%) and volume (27−29%). A high biological stability was measured on the final light fraction samples collected from both the tests. Furthermore, the lower heating value obtained after the biodrying treatment complies with the quality specification of the European standard on refuse-derived fuels.
Mass Spectroscopic Analysis, MNDO Quantum Chemical Studies and Antifungal Activity of Essential and Recovered Oil Constituents of Lemon-Scented Gum against Three Common Molds
Said I. Behiry, Ramadan A. Nasser, Mamoun S.M. Abd El-Kareem, Hayssam M. Ali, Mohamed Z.M. Salem
May 8, 2020 (v1)
Subject: Biosystems
Keywords: Corymbia citriodora, fruit oils, leaf oils, lemon-Scented Gum, mass spectrometry, MNDO Quantum, wood bio-fungicide
The present study described the possibility of using wood-treated oil-fungicide of lemon-scented gum (Corymbia citriodora) from newly emerged leaves and unripened fruits against the infestation of Fusarium culmorum, Rhizoctonia solani and Penicillium chrysogenum. Air-dried wood samples of Melia azedarach were treated with the extracted oils from leaves and unripened fruits from C. citriodora. The main chemical constituents identified in the essential oil (EO) from leaves were citronellal (55.31%), citronellol (21.03%) and isopulegol (10.79%), while in unripened fruits were α-pinene (17.86%), eudesmol (13.9%), limonene (9.19%), γ-terpinen (8.21%), and guaiol (7.88%). For recovered oils (ROs), the major components from leaves were D-limonene (70.23%), γ-terpinene (13.58%), β-pinene (2.40%) and isopregol (2.23%), while, 4-terpineol (21.35%), cis-β-terpineol, (19.33%), D-limonene (14.75%), and γ-terpinene (7.42%) represented the main components in fruits. EOs from leaves and fruits at the... [more]
Oxidative Coupling of Methane in Membrane Reactors; A Techno-Economic Assessment
Aitor Cruellas, Jelle Heezius, Vincenzo Spallina, Martin van Sint Annaland, José Antonio Medrano, Fausto Gallucci
May 8, 2020 (v1)
Keywords: chemical processes, fuel-switching scenario, membrane reactors, methane coupling, Modelling, oxygen selective membrane, Technoeconomic Analysis
Oxidative coupling of methane (OCM) is a process to directly convert methane into ethylene. However, its ethylene yield is limited in conventional reactors by the nature of the reaction system. In this work, the integration of different membranes to increase the overall performance of the large-scale oxidative coupling of methane process has been investigated from a techno-economic point of view. A 1D membrane reactor model has been developed, and the results show that the OCM reactor yield is significantly improved when integrating either porous or dense membranes in packed bed reactors. These higher yields have a positive impact on the economics and performance of the downstream separation, resulting in a cost of ethylene production of 595−625 €/tonC2H4 depending on the type of membranes employed, 25−30% lower than the benchmark technology based on oil as feedstock (naphtha steam cracking). Despite the use of a cryogenic separation unit, the porous membranes configuration shows gener... [more]
Process Parameters Optimization of Gallic Acid Removal from Water by MIEX Resin Based on Response Surface Methodology
Qiang Zhou, Lei Ding, Yunhua Zhu, Meiying Zhong, Chuchu Yang
May 2, 2020 (v1)
Keywords: Adsorption, gallic acid, MIEX resin, process parameters optimization, response surface methodology
In this work, the response surface methodology was used to optimize the process parameters of gallic acid adsorption on magnetic ion exchange (MIEX) resin. Based on Box-Behnken Design, a quadratic polynomial model equation including solution pH, gallic acid concentration, MIEX resin dosage and adsorption time was established. The reliability of the established regression equation was tested by variance analysis. Based on the regression equation, the technical parameters for gallic acid adsorption on MIEX resin were optimized and the effects of interaction between variables on the removal of gallic acid were analyzed. The results showed that the established regression equation was reliable and could effectively predict the removal of gallic acid. The optimal technical parameters were determined to be a pH of 9.17, a gallic acid concentration of 8.07 mg/L, a resin dosage of 0.98 mL/L and an adsorption time of 46.43 min. The removal efficiency of gallic acid was 97.93% under the optimal p... [more]
Green Corrosion Inhibitors from Agri-Food Wastes: The Case of Punica granatum Extract and Its Constituent Ellagic Acid. A Validation Study
Mirko Magni, Ester Postiglione, Stefania Marzorati, Luisella Verotta, Stefano P. Trasatti
May 2, 2020 (v1)
Subject: Materials
Keywords: ellagic acid, green corrosion inhibitors, iron corrosion, pomegranate extract
Giving a “new life” to wastes should be the golden rule for all production processes in the forthcoming future, aiming at making them more sustainable and environmentally friendly. In the corrosion science field, the ambitious circular economy paradigm has recently led to the employment of extracts from plants (and, in less extent, from agri-food wastes) as green inhibitors against corrosion of metals. However, in spite of the number of scientific papers published in the field, a deep revision of the scientific approach is needed both in the execution of experiments and in the critical analysis of the results. Starting from some discrepancies in published data, the corrosion inhibition effect induced by a well-characterized methanolic extract from wastes of fermented Punica granatum and by its main component (ellagic acid, EA) was validated. The corrosion behaviour of Armco® pure iron in the presence of small concentrations of ellagic acid and extract (containing ca. 10 µM and 100 µM E... [more]
An Environmental and Economic Analysis of Flocculation Technology Applied to a Corn-Based Ethanol Plant
Maria da Conceição T. B. e Oliveira, Kurt A. Rosentrater
May 2, 2020 (v1)
Keywords: bioflocculants, Ethanol, Wastewater
The stimulation of renewable fuel production is related to the environmental issues resulting from the extraction and utilization of fossil fuels. Although corn-based ethanol is one of the leading renewable fuels and promises to mitigate these environmental impacts, it generates large volumes of wastewater with high concentrations of organic material (CODcr > 30,000 mg/L) and low pH (3.5−4.5), which leads to serious environmental concerns. A common method of treatment of distillery wastewater is the Dry Distilled Grain Soluble (DDGS) process, which separates liquid and solid fractions; however, a disadvantage of this process is its high energy consumption. Other commonly implemented methods are often costly and not environmentally safe. To minimize these problems, a flocculation process can be applied as a potential lower energy consumption process utilizing bioflocculants, which have been proven harmless to the environment. Therefore, the main goal of this study was to analyze the eco... [more]
Cavitating Flow Suppression in the Draft Tube of a Cryogenic Turbine Expander through Runner Optimization
Ning Huang, Zhenlin Li, Baoshan Zhu
May 2, 2020 (v1)
Keywords: cryogenic cavitation, draft tube, expander runner, Optimization
The application of a cryogenic liquefied natural gas expander can reduce the production of flash steam and improve the efficiency of natural gas liquefaction. Like traditional hydraulic machinery, cavitation will occur during the operation of a liquefied natural gas expander, in particular, there is a strong vortex flow in the draft tube, and the cavitation phenomenon is serious. In this paper, the energy loss coefficient of the draft tube is used to describe the cavitation flow in the draft tube, and the goal of reducing the cavitation in the draft tube is achieved through the optimization design of the runner. Different runner models within the range of design parameters were obtained using the Latin hypercube test, and the relationship between design parameters and objective functions is constructed by a second-order response surface model. Finally, the optimized runners were obtained using a genetic algorithm. The effects of blade loading distribution and blade lean angles on the c... [more]
Simulation of Solid Oxide Fuel Cell Anode in Aspen HYSYS—A Study on the Effect of Reforming Activity on Distributed Performance Profiles, Carbon Formation, and Anode Oxidation Risk
Khaliq Ahmed, Amirpiran Amiri, Moses O. Tadé
May 2, 2020 (v1)
Keywords: anode oxidation, carbon formation, internal reforming, Simulation, SOFC
A distributed variable model for solid oxide fuel cell (SOFC), with internal fuel reforming on the anode, has been developed in Aspen HYSYS. The proposed model accounts for the complex and interactive mechanisms involved in the SOFC operation through a mathematically viable and numerically fast modeling framework. The internal fuel reforming reaction calculations have been carried out in a plug flow reactor (PFR) module integrated with a spreadsheet module to interactively calculate the electrochemical process details. By interlinking the two modules within Aspen HYSYS flowsheeting environment, the highly nonlinear SOFC distributed profiles have been readily captured using empirical correlations and without the necessity of using an external coding platform, such as MATLAB or FORTRAN. Distributed variables including temperature, current density, and concentration profiles along the cell length, have been discussed for various reforming activity rates. Moreover, parametric estimation of... [more]
Research on Flow Characteristics of Straight Line Conjugate Internal Meshing Gear Pump
Hongqiang Chai, Guolai Yang, Guoguo Wu, Guixiang Bai, Wenqi Li
May 2, 2020 (v1)
Keywords: average flow rate, flow pulsation, gear pair’s geometric parameters, performance evaluations, simulation analysis, straight line conjugate internal meshing gear pump
The improvement of the overall performance of hydraulic pumps is the basis of intelligent hydraulics. Taking the straight line conjugate internal meshing gear pump as the research object, the theoretical flow rate and the geometric flow pulsation rate equations are established in this study through the volume change method. The change laws of the gear pair’s geometric parameters on the theoretical flow rate and the geometric flow pulsation rate are studied. The simulation model of the internal flow channel is established, and the influence factors and the influence degree of the flow pulsation and average flow rate are analyzed. The high-pressure positive displacement pump test system is also designed and built. The performance evaluations are conducted, and the experimental results are analyzed. The results show that the periodic change of the meshing point position is the root cause of the geometric flow pulsation. The theoretical flow rate and the geometric flow pulsation rate are 1... [more]
Thermal Degradation of Cassava Rhizome in Thermosyphon-Fixed Bed Torrefaction Reactor
Nitipong Soponpongpipat, Suwat Nanetoe, Paisan Comsawang
May 2, 2020 (v1)
Keywords: cassava rhizome, decomposition pathways, energy yield, thermosyphon, torrefaction
A thermosyphon-fixed bed reactor was designed and constructed to investigate the temperature distribution of the cassava rhizome and its decomposition behavior. To study the properties of torrefied char obtained from this reactor, cassava rhizome was torrefied in five different configurations, including the thermosyphon-fixed bed reactor, a laboratory reactor in compact bulk arrangement with N2 as the purge gas and without any purge gas, and another one in a hollow bulk arrangement with and without purge gas. It was found that the use of thermosyphons with a fixed bed reactor improved the uniform temperature distribution. The average heating rate to the cassava rhizome bed was 1.40 °C/min, which was 2.59 times higher than that of the fixed bed reactor without thermosyphons. Compared to the other configurations, this reactor gave the highest higher heating value (HHV) and the lowest mass yield of 23.97 MJ/kg and 47.84%, respectively. The water vapor produced in this reactor played an au... [more]
Metabolomic Profiling and Antioxidant, Anticancer and Antimicrobial Activities of Hyphaene thebaica
Ghada A. Taha, Ibrahim B. Abdel-Farid, Hassan A. Elgebaly, Usama A. Mahalel, Mohamed G. Sheded, May Bin-Jumah, Ayman M. Mahmoud
May 2, 2020 (v1)
Subject: Biosystems
Keywords: anticancer, antimicrobial, antioxidant, doum palm, polyphenols
This study investigated the metabolic content and biological activities of Hyphaene thebaica leaves, male parts and fruits methanolic extracts. The phytochemical constituents were determined, and multivariate data analysis discriminated the evaluated three parts into three groups according to the content of phenolics, flavonoids, flavonols, saponins, anthocyanins and tannins. High-performance liquid chromatography (HPLC) profiling of polyphenols revealed the dominance of catechins, rutin and apigenin-7-glucosides in leaves, protocatechuin, p-hydroxybenzoic, syringic, vanillic, rosmarinic, p-coumaric acids and chrysin in male parts, and chlorogenic acid in fruits. Leaves and male parts showed stronger free radical scavenging activity than the fruits. Positive correlations between total antioxidant capacity and carbohydrates, phenolics and flavonols were observed. The three extracts exhibited potent anti-cancer activity against liver and lung carcinoma cell lines. All extracts exhibited... [more]
Steel Wool for Water Treatment: Intrinsic Reactivity and Defluoridation Efficiency
Benjamin Hildebrant, Arnaud Igor Ndé-Tchoupé, Mesia Lufingo, Tobias Licha, Chicgoua Noubactep
May 2, 2020 (v1)
Keywords: dye discoloration, ethylenediaminetetraacetic acid, intrinsic reactivity, water defluoridation, zero-valent iron
Studies were undertaken to characterize the intrinsic reactivity of Fe0-bearing steel wool (Fe0 SW) materials using the ethylenediaminetetraacetate method (EDTA test). A 2 mM Na2-EDTA solution was used in batch and column leaching experiments. A total of 15 Fe0 SW specimens and one granular iron (GI) were tested in batch experiments. Column experiments were performed with four Fe0 SW of the same grade but from various suppliers and the GI. The conventional EDTA test (0.100 g Fe0, 50 mL EDTA, 96 h) protocol was modified in two manners: (i) Decreasing the experimental duration (down to 24 h) and (ii) decreasing the Fe0 mass (down to 0.01 g). Column leaching studies involved glass columns filled to 1/4 with sand, on top of which 0.50 g of Fe0 was placed. Columns were daily gravity fed with EDTA and effluent analyzed for Fe concentration. Selected reactive Fe0 SW specimens were additionally investigated for discoloration efficiency of methylene blue (MB) in shaken batch experiments (75 rpm... [more]
Exergo-Economic Optimization of Organic Rankine Cycle for Saving of Thermal Energy in a Sample Power Plant by Using of Strength Pareto Evolutionary Algorithm II
Sina Mehrdad, Reza Dadsetani, Alireza Amiriyoon, Arturo S. Leon, Mohammad Reza Safaei, Marjan Goodarzi
May 2, 2020 (v1)
Keywords: energy management, evolutionary algorithm, exergo-economic optimization, heat recovery, organic fluid, organic Rankine cycle, SPEA II
Waste heat recovery plays an important role in energy source management. Organic Rankine Cycle (ORC) can be used to recover low-temperature waste heat. In the present work a sample power plant waste heat was used to operate an ORC. First, two pure working fluids were selected based on their merits. Four possible thermodynamic models were considered in the analysis. They were defined based on where the condenser and evaporator temperatures are located. Four main thermal parameters, evaporator temperature, condenser temperature, degree of superheat and pinch point temperature difference were taken as key parameters. Levelized energy cost values and exergy efficiency were calculated as the optimization criteria. To optimize exergy and economic aspects of the system, Strength Pareto evolutionary algorithm II (SPEA II) was implemented. The Pareto frontier solutions were ordered and chose by TOPSIS. Model 3 outperformed all other models. After evaluating exergy efficiency by mixture mass fra... [more]
The Potential Production of the Bioactive Compound Pinene Using Whey Permeate
Derrick Risner, Maria L. Marco, Sara A. Pace, Edward S. Spang
May 2, 2020 (v1)
Keywords: biosynthesis, Escherichia coli, microbial, pinene, terpene, whey, whey permeate
Pinene is a secondary plant metabolite that has functional properties as a flavor additive as well as potential cognitive health benefits. Although pinene is present in low concentrations in several plants, it is possible to engineer microorganisms to produce pinene. However, feedstock cost is currently limiting the industrial scale-up of microbial pinene production. One potential solution is to leverage waste streams such as whey permeate as an alternative to expensive feedstocks. Whey permeate is a sterile-filtered dairy effluent that contains 4.5% weight/weight lactose, and it must be processed or disposed of due its high biochemical oxygen demand, often at significant cost to the producer. Approximately 180 million m3 of whey is produced annually in the U.S., and only half of this quantity receives additional processing for the recovery of lactose. Given that organisms such as recombinant Escherichia coli grow on untreated whey permeate, there is an opportunity for dairy producers... [more]
Near-Null Geomagnetic Field as an Innovative Method of Fruit Storage
Grzegorz Zaguła, Maria Tarapatskyy, Marcin Bajcar, Bogdan Saletnik, Czesław Puchalski, Andrzej Marczuk, Dariusz Andrejko, Jan Oszmiański
May 2, 2020 (v1)
Keywords: apples storage, chemical profile, compensation, geomagnetic field, sugars
The article presents the findings of a study investigating the effects of storing Jonagold apples for six weeks in a condition in which the vertical component of the geomagnetic field has been eliminated (near null GMF) and in control conditions representing those applied in traditional storage (i.e., in the local geomagnetic field (local GMF)). Analyses of the fruit were performed before the start of and three times during the experiment (i.e., following four, five and six weeks in storage). The contents of simple sugars were measured using the HPLC (high performance liquid chromatography) method; refractometry was applied to identify total extract; thermogravimetry was used to measure the water content, volatile substances and total ash; calorific value and intensity of respiration were examined by measuring CO2 emissions. Significant differences were found between the apples stored in the experimental and under control conditions, showing an advantage of storage in a condition with... [more]
Numerical Analysis of High-Pressure Direct Injection Dual-Fuel Diesel-Liquefied Natural Gas (LNG) Engines
Alberto Boretti
May 2, 2020 (v1)
Keywords: compression ignition, cryogenic gas, diesel engines, direct injection, dual fuel engines, greenhouse gas emissions, Natural Gas, particulate matter
Dual fuel engines using diesel and fuels that are gaseous at normal conditions are receiving increasing attention. They permit to achieve the same (or better) than diesel power density and efficiency, steady-state, and substantially similar transient performances. They also permit to deliver better than diesel engine-out emissions for CO2, as well as particulate matter, unburned hydrocarbons, and nitrous oxides. The adoption of injection in the liquid phase permits to further improve the power density as well as the fuel conversion efficiency. Here, a model is developed to study a high-pressure, 1600 bar, liquid phase injector for liquefied natural gas (LNG) in a high compression ratio, high boost engine. The engine features two direct injectors per cylinder, one for the diesel and one for the LNG. The engine also uses mechanically assisted turbocharging (super-turbocharging) to improve the steady-state and transient performances of the engine, decoupling the power supply at the turbin... [more]
Evolution of Phase Composition and Antibacterial Activity of Zr−C Thin Films
Katarzyna Mydłowska, Ewa Czerwińska, Adam Gilewicz, Ewa Dobruchowska, Ewa Jakubczyk, Łukasz Szparaga, Przemysław Ceynowa, Jerzy Ratajski
May 2, 2020 (v1)
Subject: Materials
Keywords: antimicrobial properties, medical implants, thin films, zirconium carbide
The research presented in this article concerns Zr−C coatings which were deposited on 304L steel by reactive magnetron sputtering from the Zr target in an Ar−C2H2 atmosphere at various acetylene flow rates, resulting in various atomic carbon concentrations in the coating. The article describes research covering the change in the antibacterial and anticorrosive properties of these coatings due to the change in their chemical and phase composition. The concentration of C in the coatings varied from 21 to 79 at.%. The coating morphology and the elemental distribution in individual coatings were characterized using field emission scanning electron microscopy with an energy-dispersive X-ray analytical system. X-ray diffraction and Raman spectroscopy were used to analyze their microstructure and phase composition. Parallel changes in the mechanical properties of the coatings were analyzed. Based on the obtained results, it was concluded that the wide possibility of shaping the mechanical pro... [more]
Isolation, Identification and Antimicrobial Evaluation of Bactericides Secreting Bacillus subtilis Natto as a Biocontrol Agent
Jing Zhang, Muhammad Bilal, Shuai Liu, Jiaheng Zhang, Hedong Lu, Hongzhen Luo, Chuping Luo, Hao Shi, Hafiz M. N. Iqbal, Yuping Zhao
May 2, 2020 (v1)
Subject: Biosystems
Keywords: antimicrobial activity, Bacillus subtilis natto, bactericides, biocontrol agent, isolation, medium optimization, molecular identification, spectral analyses
Herein, a bactericide-secreting Bacillus strain, potentially useful as a biocontrol agent, was isolated from the commercial Yanjing Natto food. Following the biochemical and physiological evaluation, the molecular identification was performed using 16S rDNA sequencing of polymerase chain reaction-amplified DNA that confirmed the natto isolate as Bacillus subtilis natto (B. subtilis natto). The biocontrol (microbial inhibitory) capability of B. subtilis natto was investigated against Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and yeast (Yarrowia lipolytica) and recorded. The antimicrobial activity of B. subtilis natto was further enhanced by optimizing the growth medium for optimal bactericides secretion. Under optimized conditions, B. subtilis natto exhibited much higher inhibitory activity against S. aureus with a zone of inhibition diameter up to 27 mm. After 48 h incubation, the optimally yielded B. subtilis natto broth was used to extract and purify the respon... [more]
3D Magneto-Buoyancy-Thermocapillary Convection of CNT-Water Nanofluid in the Presence of a Magnetic Field
Lioua Kolsi, Salem Algarni, Hussein A. Mohammed, Walid Hassen, Emtinene Lajnef, Walid Aich, Mohammed A. Almeshaal
May 2, 2020 (v1)
Keywords: buoyancy thermocapillary convection, CNT-water nanofluid, flow control., magnetic field direction, Marangoni number
A numerical study is performed to investigate the effects of adding Carbon Nano Tube (CNT) and applying a magnetic field in two directions (vertical and horizontal) on the 3D-thermo-capillary natural convection. The cavity is differentially heated with a free upper surface. Governing equations are solved using the finite volume method. Results are presented in term of flow structure, temperature field and rate of heat transfer. In fact, results revealed that the flow structure and heat transfer rate are considerably affected by the magnitude and the direction of the magnetic field, the presence of thermocapillary forces and by increasing nanoparticles volume fraction. In opposition, the increase of the magnetic field magnitude leads to the control the flow causing flow stabilization by merging vortexes and reducing heat transfer rate.
An Overview of the Biolubricant Production Process: Challenges and Future Perspectives
Juan Antonio Cecilia, Daniel Ballesteros Plata, Rosana Maria Alves Saboya, Francisco Murilo Tavares de Luna, Celio L. Cavalcante Jr, Enrique Rodríguez-Castellón
May 2, 2020 (v1)
Keywords: applications, biolubricant, chemical modification, future perspective, physicochemical properties, vegetable oil
The term biolubricant applies to all lubricants that are easily biodegradable and non-toxic to humans and the environment. The uses of biolubricant are still very limited when compared to those of mineral oils, although this trend is increasing and depends on investment in research and development (R&D). The increase in demand for biodegradable lubricants is related to the evolution of environmental regulations, with more restrictive rules being implemented to minimize environmental impact caused by inappropriate disposal. This study provides an overview of the types, production routes, properties, and applications of biolubricants. Biolubricants are classified as either natural or synthetic oils according to chemical composition. Natural oils are of animal or vegetable origin and are rarely used because they are unstable at high temperatures and form compounds that are harmful to equipment and machines. Synthetic oils are obtained from chemical reactions and are the best lubricants fo... [more]
Nutritional Quality and Physico-Chemical Characteristics of Selected Date Fruit Varieties of the United Arab Emirates
Krishnamoorthy Rambabu, Govindan Bharath, Abdul Hai, Fawzi Banat, Shadi W. Hasan, Hanifa Taher, Hayyiratul Fatimah Mohd Zaid
May 2, 2020 (v1)
Subject: Biosystems
Keywords: amino acids, biomaterials, date fruits, date sugar, physico-chemical characteristics, phytoconstituents, proximate analysis
Production of highly soluble date sugar powder from the nutritive date fruits will be a suitable and superior alternative to commercial refined sugar, providing sustainability in date palm cultivation. A good understanding of the nutritional and phytochemical composition of date fruits is imperative for this purpose. In this work, 11 different date fruit species commonly cultivated in the United Arab Emirates were studied for their chemical composition, physical properties, amino acids, minerals, and anti-nutritional contents. The results revealed that the date fruits contain moisture, protein, lipid, and ash content in the ranges of 14.8%−20.5%, 2.19%−3.12%, 0.25%−0.51%, and 1.37%−1.97%, respectively. Potassium was identified as the major microelement in all the date varieties. Amino acid assay depicted that the date fruits mainly contained glutamine and aspartic acids, along with other essential acids. Monosaccharides (glucose and fructose) were more prevalent in the date fruits than... [more]
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