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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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.

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]

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]

Order-lot matching is the process of assigning items in lots being processed in the make-to-order production system to meet the due dates of the orders. In this study, an order-lot matching problem (OLMP) is considered to minimize the total tardiness of orders with different due dates. In the OLMP considered in this study, we need to not only determine the allocation of items to lots in the production facility but also generate a lot release plan for the given time horizon. We show that the OLMP can be considered as a special type of machine scheduling problem with many similarities to the single machine total tardiness scheduling problem ( 1 | | ∑ T i ). We suggest dominance conditions for the OLMP by modifying those for 1 | | ∑ T i and a dynamic programming (DP) model based on the dominance conditions. With two example problems, we show that the DP model can solve small-sized OLMPs optimally.

The trends and challenges of pyrolysis technology nowadays have shifted to low-temperature pyrolysis, which provides low-cost processes but high-yield conversion, with suitable H2/CO ratios for performing gas-to-liquid technology in the future. The present study has developed a modified vacuum pyrolysis reactor to convert sugarcane bagasse to gas products, including H2, CO2, CH4, and CO in the low-temperature process. The experimental design includes the effects of pyrolysis time, pyrolysis temperature, and applying a current as a function of the electromagnetic field. The result showed that 0.12 ng/µL, 0.85 ng/µL, and 0.31 ng/µL of hydrogen (H2), carbon dioxide (CO2), and carbon monoxide (CO) gases, respectively, started forming in the first 20 min at 210 °C for the pyrolysis temperature, and the gas product accumulated in the increase of pyrolysis time and temperature. In the absence of electromagnetic field, the optimum condition was obtained at 60 min and 290 °C of pyrolysis time a... [more]

YVO4:Eu3+ nanoparticles were successfully synthesized by two methods, namely the sonochemical method and hydrothermal method. The X-ray diffraction (XRD) patterns showed the tetragonal phase of YVO4 (JCPDS 17-0341) was indexed in the diffraction peaks of all samples. The samples synthesized by the sonochemical method had a highly crystalline structure (X-ray diffraction results) and luminescence intensity (photoluminescence results) than those synthesized by the hydrothermal method. According to the results of field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), the average size of YVO4:Eu3+ nanoparticles was around 25−30 nm for the sonochemical method and 15−20 nm for the hydrothermal method. YVO4:Eu3+ nanoparticles in the case of the sonochemical method had a better crystalline structure and stronger emissivity at 618 nm. The Eu3+ ions’ average lifetime in YVO4:Eu3+ at 618 nm emission under 275 nm excitation were at 0.955 ms for the sonoche... [more]

The optimum design of gas drainage boreholes is crucial for energy security and sustainability in coal mining. Therefore, the construction of fluid−solid coupling models and numerical simulation analyses are key problems for gas drainage boreholes. This work is based on the basic theory of fluid−solid coupling, the correlation definition between coal porosity and permeability, and previous studies on the influence of adsorption expansion, change in pore free gas pressure, and the Klinkenberg effect on gas flow in coal. A mathematical model of the dynamic evolution of coal permeability and porosity is derived. A fluid−solid coupling model of gas-bearing coal and the related partial differential equation for gas migration in coal are established. Combined with an example of the measurement of the drilling radius of the bedding layer in a coal mine, a coupled numerical solution under negative pressure extraction conditions is derived by using COMSOL Multiphysics simulation software. Numer... [more]

Targeted therapies of various diseases are nowadays widely studied in many biomedical fields. Photodynamic therapy (PDT) represents a modern treatment of cancer using a locally activated light. TMPyP is an efficient synthetic water-soluble photosensitizer (PS), yet with poor absorption in the visible and the red regions. In this work, we prepared size-selected and colloidally stable graphene oxide (GO) that is appropriate for biomedical use. Thanks to the negative surface charge of GO, TMPyP was easily linked in order to create conjugates of GO/TMPyP by electrostatic force. Due to the strong ionic interactions, charge transfers between GO and TMPyP occur, as comprehensively investigated by steady-state and time-resolved fluorescence spectroscopy. Biocompatibility and an in vitro effect of GO/TMPyP were confirmed by a battery of in vitro tests including MTT, comet assay, reactive oxygen species (ROS) production, and monitoring the cellular uptake. PDT efficiency of GO/TMPyP was tested u... [more]

Cities are becoming smarter by incorporating hardware technology, software systems, and network infrastructure that provide Information Technology (IT) systems with real-time awareness of the real world. What makes a “smart city” functional is the combined use of advanced infrastructure technologies to deliver its core services to the public in a remarkably efficient manner. City dashboards have drawn increasing interest from both city operators and citizens. Dashboards can gather, visualize, analyze, and inform regional performance to support the sustainable development of smart cities. They provide useful tools for evaluating and facilitating urban infrastructure components and services. This work proposes an interactive web-based data visualization and data analytics toolkit supported by big data aggregation tools. The system proposed is a cloud-based prototype that supports visualization and real-time monitoring of city trends while processing and displaying large data sets on a st... [more]