As is well known to mineral processing scientists and engineers, fine and ultrafine particles are difficult to float mainly due to the low bubble-particle collision efficiencies. Though many efforts have been made to ...As is well known to mineral processing scientists and engineers, fine and ultrafine particles are difficult to float mainly due to the low bubble-particle collision efficiencies. Though many efforts have been made to improve flotation performance of fine and ultrafine particles, there is still much more to be done. In this paper, the effects of nano-microbubbles （nanobuhbles and microbubbles） on the flotation of fine （-38 ＋ 14.36 μm） and ultrafine （-14.36 ＋ 5μm） chalcopyrite particles were investigated in a laboratory scale Denver flotation cell. Nano-microbubbles were generated using a specially-designed nano- microbubble generator based on the cavitation phenomenon in Venturi tubes. In order to better under- stand the mechanisms of nano-microbubble enhanced froth flotation of fine and ultrafine chalcopyrite particles, the nano-microbubble size distribution, stability and the effect of frother concentration on nano- bubble size were also studied by a laser diffraction method. Comparative flotation tests were performed in the presence and absence of nano-microbubbles to evaluate their impact on the fine and ultrafine chalcopyrite particle flotation recovery. According to the results, the mean size of nano-microbubbles increased over time, and decreased with increase of frother concentration. The laboratory-scale flotation test results indicated that flotation recovery of chalcopyrite fine and ultrafine particles increased by approximately 16-21% in the presence of nano-microbubbles, depending on operating conditions of the process. The presence of nano-microbubbles increased the recovery of ultrafine particles （-14.36 ＋ 5 μm） more than that of fine particles （-38 ＋ 14.36 μm）. Another major advantage is that the use of nano-microbubbles reduced the collector and frother consumptions by up to 75% and 50%, respectively.展开更多
Modification and performance of Li induced silica phase transition of （Mn＋W）/SiO2 catalyst, under reaction conditions of oxidative coupling of methane （OCM）, have been investigated employing textural characteriza...Modification and performance of Li induced silica phase transition of （Mn＋W）/SiO2 catalyst, under reaction conditions of oxidative coupling of methane （OCM）, have been investigated employing textural characterizations and redox studies. Stability and precrystalline form of fresh Li induced silica phase transition catalyst depend on the Li loading. A catalyst, with high lithium loading, destabilizes on OCM stream. This destabilization is not due to Li evaporation at OCM reaction conditions, α-cristobalite is proposed to be an intermediate in the crystallization of amorphous silica into quartz in the Li-induced silica phase transition process. However, the type of crystalline structure was found to be unimportant with regard to the formation of a selective catalyst. Metal-metal interactions of Li-Mn, Li-W and Mn-W, which are affected during silica phase crystallization, are found to be critical parameters of the trimetallic catalyst and were studied by TPR. Role of lithium in Li doped （Mn＋W）/SiO2 catalyst is described as a moderator of the Mn-W interaction by involving W in silica phase transition. These interactions help in the improvement of transition metal redox properties, especially that of Mn, in favor of OCM selectivity.展开更多
In the present study,CNFs,ZnO and Al2O3 were deposited on the SMFs panels to investigate the deactivation mechanism of Pd-based catalysts in selective acetylene hydrogenation reaction.The examined supports were charac...In the present study,CNFs,ZnO and Al2O3 were deposited on the SMFs panels to investigate the deactivation mechanism of Pd-based catalysts in selective acetylene hydrogenation reaction.The examined supports were characterized by SEM,NH3-TPD and N2adsorption-desorption isotherms to indicate their intrinsic characteristics.Furthermore,in order to understand the mechanism of deactivation,the resulted green oil was characterized using FTIR and SIM DIS.FTIR results confirmed the presence of more unsaturated constituents and then,more branched hydrocarbons formed upon the reaction over alumina-supported catalyst in comparison with the ones supported on CNFs and ZnO,which in turn,could block the pores mouths.Besides the limited hydrogen transfer,N2 adsorption-desorption isotherms results supported that the lowest pore diameters of Al2O3/SMFs close to the surface led to fast deactivation,compared with the other catalysts,especially at higher temperatures.展开更多
This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial desig...This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.展开更多
This research paper presents a novel optimization method called the Synergistic Swarm Optimization Algorithm(SSOA).The SSOA combines the principles of swarmintelligence and synergistic cooperation to search for optima...This research paper presents a novel optimization method called the Synergistic Swarm Optimization Algorithm(SSOA).The SSOA combines the principles of swarmintelligence and synergistic cooperation to search for optimal solutions efficiently.A synergistic cooperation mechanism is employed,where particles exchange information and learn from each other to improve their search behaviors.This cooperation enhances the exploitation of promising regions in the search space while maintaining exploration capabilities.Furthermore,adaptive mechanisms,such as dynamic parameter adjustment and diversification strategies,are incorporated to balance exploration and exploitation.By leveraging the collaborative nature of swarm intelligence and integrating synergistic cooperation,the SSOAmethod aims to achieve superior convergence speed and solution quality performance compared to other optimization algorithms.The effectiveness of the proposed SSOA is investigated in solving the 23 benchmark functions and various engineering design problems.The experimental results highlight the effectiveness and potential of the SSOA method in addressing challenging optimization problems,making it a promising tool for a wide range of applications in engineering and beyond.Matlab codes of SSOA are available at:https://www.mathworks.com/matlabcentral/fileexchange/153466-synergistic-swarm-optimization-algorithm.展开更多
In the present study,a novel approach based on an evolutionary wavelet neural network(EWNN)is proposed to estimate the slag quality in an electric arc furnace(EAF)employing power quality indices.In the EWNN,an evoluti...In the present study,a novel approach based on an evolutionary wavelet neural network(EWNN)is proposed to estimate the slag quality in an electric arc furnace(EAF)employing power quality indices.In the EWNN,an evolutionary method is applied to train the parameters for a combination of neural networks and wavelets.I For this purpose,all of the electrical parameters for six melting processes are measured with a power quality analyzer,attached to the secondary component of an EAF transformer at a Saba steel complex,to estimate the foaming slag quality.Experimental results on various combinations of measured electrical parameters,applying the designed EWNN estimator,demonstrate that utilizing five leading indicators leads to the highest precision.The obtained 99%accuracy for estimating the foaming slag quality by EWNN compared to the other methods illustrates the proposed method's efficiency.展开更多
The effects of manganese oxide or ceria promoters on the performance of Na2WO4/SiO2 catalysts for oxidative coupling of methane （OCM） are reported. The OCM reaction was performed in a continuous-flow microreactor at...The effects of manganese oxide or ceria promoters on the performance of Na2WO4/SiO2 catalysts for oxidative coupling of methane （OCM） are reported. The OCM reaction was performed in a continuous-flow microreactor at 800℃, atmospheric pressure and under GHSV = 13200 ml·gCat^-1·h^-1.Catalysts were characterized by in situ conductivity measurement, FT-IR spectroscopy, XRD, SEM and temperature programmed reduction analysis. Manganese oxide promoted Na2WO4/SiO2 is considered as one of the active and selective catalysts for OCM reaction. Ceria with high oxygen storage capacity is selected as a proper oxygen activator, providing a higher concentration of the oxy-anion species which is suitable for OCM reaction and compared with manganese oxide. Electrical conductivity of the catalysts was measured in OCM reaction under oxidizing atmosphere, i.e. in the absence of methane. It was found that the trimetallic catalysts, i.e. the catalysts having sodium, tungsten and Mn or Ce species, exhibited similar crystalline structures and morphologies, which lead to suitable bulk properties for the formation of an active and selective catalyst. However, tungsten had significant effect on the texture and redox properties of the catalysts. It was also shown that the crystalline structure of the bimetallic （Na＋Mn or Ce）/SiO2 samples was quite different. This reveals that the metal oxides have significant effect on the extent of crystallization, taking place in the course of interaction of sodium with silica support. Similar conductivities and catalytic performances of （Na2WO4＋Mn or Ce）/SiO2 catalysts propose that the ability of Na2WO4/SiO2 for utilizing oxy-anions formed in presence of different metal oxides is limited.展开更多
Utilizing the phase change materials in different thermal storage applications attains valuable attention due to the fascinating thermal properties of these materials.The comprehension of the thermal behaviour of phas...Utilizing the phase change materials in different thermal storage applications attains valuable attention due to the fascinating thermal properties of these materials.The comprehension of the thermal behaviour of phase change materials during the melting and solidification is considered a significant priority in designing the shape of the different containers.In this review,analytical,computational and experimental investigations that address solidification/freezing of phase change materials within thermal energy storage systems are discussed.Emphasis is placed on the role of the shape of adopted containers encompassing planar,spherical,cylindrical and annular vessels.Energy storage for solar thermal applications,waste heat recovery,and thermal management of buildings/computing platforms/photovoltaics has been the topics that benefit from these investigations.For all container shapes,the freezing process is controlled initially by natural convection,and a high solidification rate is observed.Later,the conduction dominates the process,and the freezing rate declines.The temperature and flow of cooling heat transfer fluid affect the solidification process,but the impact of heat transfer fluid temperature is more significant than its flow rate.Also,the freezing time increases with the container’s size and amount of contained PCM.The aspect ratio of the planar and vertical cylindrical cavities substantially influences the discharging time and rate.In contrast,the orientation of the annular cavity has a lower impact on the discharging process.展开更多
A series of organic compounds were successfully immobilized on an N-doped graphene quantum dot (N-GQD) to prepare a multifunctional organocatalyst for coupling reaction between CO_(2)and propylene oxide (PO).The simul...A series of organic compounds were successfully immobilized on an N-doped graphene quantum dot (N-GQD) to prepare a multifunctional organocatalyst for coupling reaction between CO_(2)and propylene oxide (PO).The simultaneous presence of halide ions in conjunction with acidic-and basic-functional groups on the surface of the nanoparticles makes them highly active for the production of propylene carbonate (PC).The effects of variables such as catalyst loading,reaction temperature,and structure of substituents are discussed.The proposed catalysts were characterized by different techniques,including Fourier transform infrared spectroscopy (FTIR),field emission scanning electron microscopy/energy dispersive X-ray microanalysis (FESEM/EDX),thermogravimetric analysis (TGA),elemental analysis,atomic force microscopy (AFM),and ultraviolet–visible (UV-Vis) spectroscopy.Under optimal reaction conditions,3-bromopropionic acid (BPA) immobilized on N-GQD showed a remarkable activity,affording the highest yield of 98%at 140℃ and 106Pa without any co-catalyst or solvent.These new metal-free catalysts have the advantage of easy separation and reuse several times.Based on the experimental data,a plausible reaction mechanism is suggested,where the hydrogen bonding donors and halogen ion can activate the epoxide,and amine functional groups play a vital role in CO_(2)adsorption.展开更多
As the COVID-19 pandemic unfolded,questions arose as to whether the pandemic would amplify or pacify tropical deforestation.Early reports warned of increased deforestation rates;however,these studies were limited to a...As the COVID-19 pandemic unfolded,questions arose as to whether the pandemic would amplify or pacify tropical deforestation.Early reports warned of increased deforestation rates;however,these studies were limited to a few months in 2020 or to selected regions.To better understand how the pandemic infl uenced tropical deforestation globally,this study used historical deforestation data(2004–2019)from the Terra-i pantropical land cover change monitoring system to project expected deforestation trends for 2020,which were used to determine whether observed deforestation deviated from expected trajectories after the fi rst COVID-19 cases were reported.Time series analyses were conducted at the regional level for the Americas,Africa and Asia and at the country level for Brazil,Colombia,Peru,the Democratic Republic of Congo and Indonesia.Our results suggest that the pandemic did not alter the course of deforestation trends in some countries(e.g.,Brazil,Indonesia),while it did in others(e.g.,Peru).We posit the importance of monitoring the long-term eff ects of the pandemic on deforestation trends as countries prioritize economic recovery in the aftermath of the pandemic.展开更多
Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pr...Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pretreatment steps (reduction and activation) and their effect on catalytic performance for iron based catalysts.In this study,Fe-Cu-La-SiO2 catalysts were prepared by co-precipitation method.To investigate the intraparticle mass transfer limitation under reduction,activation and reaction steps,and its effect on catalytic performance,catalyst pellets with different sizes of 6,3,1 and 0.5 mm have been prepared.All catalysts were calcined,pretreated and tested under similar conditions.The catalysts were activated in hydrogen (5%H2in N2) at 450℃ for 3 h and exposed to syngas (H2/CO=1) at 270℃ and atmospheric pressure for 40 h.Afterwards,FTS reaction tests were performed for approximately 120 h to reach steady state conditions at 290℃,17 bar and a feed flow (syngas H2/CO=1) rate of 3 L/h (STP).Using small pellets resulted in higher CO conversion,FT reaction rate and C5+ productivity as compared with larger pellets.The small pellets reached steady state conditions just 20 h after starting the reaction.Whereas for larger pellets,CO conversion,FT reaction rate and C5+ productivity increased gradually,and reached steady state and maximum values after 120 h of operation.The results illustrate that mass transfer limitations exist not only for FTS reaction but also for the reduction and carburization steps which lead to various phase formation through catalyst activation.Also the results indicate that some effects of mass transfer limitations in activation step,can be compensated in the reaction step.The results can be used for better design of iron based catalyst to improve the process economy.展开更多
This paper uses the Butterfly Optimization Algorithm(BOA)with dominated sorting and crowding distance mechanisms to solve multi-objective optimization problems.There is also an improvement to the original version of B...This paper uses the Butterfly Optimization Algorithm(BOA)with dominated sorting and crowding distance mechanisms to solve multi-objective optimization problems.There is also an improvement to the original version of BOA to alleviate its drawbacks before extending it into a multi-objective version.Due to better coverage and a well-distributed Pareto front,non-dominant rankings are applied to the modified BOA using the crowding distance strategy.Seven benchmark functions and eight real-world problems have been used to test the performance of multi-objective non-dominated advanced BOA(MONSBOA),including unconstrained,constrained,and real-world design multiple-objective,highly nonlinear constraint problems.Various performance metrics,such as Generational Distance(GD),Inverted Generational Distance(IGD),Maximum Spread(MS),and Spacing(S),have been used for performance comparison.It is demonstrated that the new MONSBOA algorithm is better than the compared algorithms in more than 80%occasions in solving problems with a variety of linear,nonlinear,continuous,and discrete characteristics based on the Pareto front when compared quantitatively.From all the analysis,it may be concluded that the suggested MONSBOA is capable of producing high-quality Pareto fronts with very competitive results with rapid convergence.展开更多
By FP-LAPW calculations, the structural, elastic, Debye and Curie temperatures, electronic and magnetic properties of Co2 VAl are investigated. The results indicate that Ferromagnetic （FM） phase is more stable than ...By FP-LAPW calculations, the structural, elastic, Debye and Curie temperatures, electronic and magnetic properties of Co2 VAl are investigated. The results indicate that Ferromagnetic （FM） phase is more stable than Anti- Ferromagnetic （AFM） and Non-magnetic （NM） ones. In addition, C11-C12 〉 0, C44 〉 0, and B 〉 0 so Co2 VAl is an elastically stable material with high Debye temperature. Also, the BIG ratio exhibits a ductility behavior. The relatively high Curie temperature provides it as a favorable material for spintronic application. It＇s electronic and magnetic properties are studied by GGA ＋U approach leading to a 100% spin polarization at Fermi level.展开更多
Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt （K-Ru-Co/γ-Al 2 O 3 ） Fischer-Tropsch （FT） synthesis catalyst along the catalytic bed over 120 h of time-on-stream （TOS） was inv...Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt （K-Ru-Co/γ-Al 2 O 3 ） Fischer-Tropsch （FT） synthesis catalyst along the catalytic bed over 120 h of time-on-stream （TOS） was investigated. Catalytic bed was divided into three parts and structural changes of the spent catalysts collected from each catalytic bed after FT synthesis were studied using different techniques. Rapid deactivation was observed during the reaction due to high reaction temperature and low feed flow rates. The physico-chemical properties of the catalyst charged in the Bed #1 of the reactor did not change significantly. Interaction of cobalt with alumina and the formation of CoAl 2 O 4 increased along the catalytic bed. Reducibility percentage decreased by 4.5%, 7.5% and 12.9% for the catalysts in the Beds #1, #2 and #3, respectively. Dispersion decreased by 8.8%, 14.4% and 26.6% for the catalysts in the Beds #1, #2 and #3, respectively. Particle diameter increased by 0.6%, 2.4% and 10.4% for the catalysts in the Beds #1, #2 and #3, respectively, suggesting higher rate of sintering at the last catalytic bed. The amount of coke at the last catalytic bed was significantly higher than those of Beds #1 and #2.展开更多
Managing physical objects in the network’s periphery is made possible by the Internet of Things(IoT),revolutionizing human life.Open attacks and unauthorized access are possible with these IoT devices,which exchange ...Managing physical objects in the network’s periphery is made possible by the Internet of Things(IoT),revolutionizing human life.Open attacks and unauthorized access are possible with these IoT devices,which exchange data to enable remote access.These attacks are often detected using intrusion detection methodologies,although these systems’effectiveness and accuracy are subpar.This paper proposes a new voting classifier composed of an ensemble of machine learning models trained and optimized using metaheuristic optimization.The employed metaheuristic optimizer is a new version of the whale optimization algorithm(WOA),which is guided by the dipper throated optimizer(DTO)to improve the exploration process of the traditionalWOA optimizer.The proposed voting classifier categorizes the network intrusions robustly and efficiently.To assess the proposed approach,a dataset created from IoT devices is employed to record the efficiency of the proposed algorithm for binary attack categorization.The dataset records are balanced using the locality-sensitive hashing(LSH)and Synthetic Minority Oversampling Technique(SMOTE).The evaluation of the achieved results is performed in terms of statistical analysis and visual plots to prove the proposed approach’s effectiveness,stability,and significance.The achieved results confirmed the superiority of the proposed algorithm for the task of network intrusion detection.展开更多
Objective:Pneumocystis pneumonia(PcP)is a life-threatening infection caused by the opportunistic fungi Pneumocystis jirovecii.The emergence of the COVID-19 pandemic forced the focus of attention of health policymakers...Objective:Pneumocystis pneumonia(PcP)is a life-threatening infection caused by the opportunistic fungi Pneumocystis jirovecii.The emergence of the COVID-19 pandemic forced the focus of attention of health policymakers on these two infections due to their clinical and paraclinical similarities,which cause diagnostic dilemmas.This study was undertaken to evaluate and estimate the global prevalence and main leading risk factors of coronavirus-associated pneumocystosis(CAP).Methods:We searched related databases between December 2019 and May 2022 for studies reporting CAP.Meta-analysis was performed using StatsDirect software(version 2.7.9)according to the DerSimonian and Laird method applying the random-effects model.We evaluated heterogeneity using theχ2-based Q statistic(significant for P<0.05)and the I2 statistic(>75%indicative of“notable”heterogeneity).Moreover,an odds ratio(OR)analysis was performed for eligible data.Results:Our meta-analysis included eight studies with 923 patients hospitalized with COVID-19;among them,92 were PcP cases.The overall pooled prevalence of CAP was estimated at 11.5%.The mortality among CAP patients was lower than that of non-PcP patients(OR 1.93;95%CI 0.86-4.31).Long-term corticosteroid therapy(OR 28.22;95%CI 0.54-1480.84)was the most predisposing factor for PcP among COVID-19 patients,followed by pulmonary diseases(OR 1.46;95%CI 0.43-4.98),kidney diseases(OR 1.26;95%CI 0.21-7.49),and acute respiratory destruction syndrome(OR 1.22;95%CI 0.05-29.28).Conclusions:The prevalence of PcP among the COVID-19 population is almost similar to the pre-COVID era.However,PcP-related mortality was decreased by the emergence of the COVID-19 pandemic.Women with COVID-19 are more susceptible to PcP than men.Acute respiratory distress syndrome,kidney diseases,pulmonary diseases,and long-term corticosteroid therapy increased the risk of PcP;however,transplantation and malignancy decreased the risk for PcP among COVID-19 patients.Further retrospective,case-control,prospective,and more precisely sy展开更多
Thin films produced by electrostatic spray deposition （ESD） have nanometer-sized structures despite the initial sprayed droplets being typically a few tens of microns in diameter. The size and morphology of the resu...Thin films produced by electrostatic spray deposition （ESD） have nanometer-sized structures despite the initial sprayed droplets being typically a few tens of microns in diameter. The size and morphology of the resulting structures is not only affected by the solvent properties and drying kinetics, hut also by Coulomb fission owing to the high surface charge density that the droplets build up upon evaporation. In this work we modulate the charge density of the droplets by inducing ionic wind along the spray, and produce mesoscopic structures. Using WO3 as an example, we show that the technique provides a practical way to control the morphology of thin films produced by ESD.展开更多
Objective:To evaluate the effect of resveratrol against CCl4-induced nephrotoxicity.Methods:Forty-two male Wistar rats were divided into seven groups randomly.After six weeks,kidney weight,body weight,blood urea,serum...Objective:To evaluate the effect of resveratrol against CCl4-induced nephrotoxicity.Methods:Forty-two male Wistar rats were divided into seven groups randomly.After six weeks,kidney weight,body weight,blood urea,serum creatinine,oxidative stress markers,and gene expression of renal transforming growth factor-beta1(TGF-β1),TGF-βreceptor type 1(TGF-βR1)and Smad3 were determined.In addition,the protein level of TGF-β1 in the tissue lysate was measured.Results:Resveratrol had a protective role in renal tissue by the improvement of antioxidant balance and reduction of renal parameters such as creatinine and urea(P<0.001).In addition,the renal m RNA level of TGF-β1,TGF-βR1,Smad3,as well as the protein level of TGF-β1 were decreased in rats treated with resveratrol(P<0.001),compared to the CCl4 group.Conclusions:Overall,resveratrol shows a protective effect against nephrotoxicity in CCl4 treated rats by reducing oxidative stress status and modulating the TGF-βsignaling.展开更多
Objective: To investigate the effect of fosbac on some blood biochemical variables in broilers. Methods: Fosbac with the dose of 160 and 320 mg/kg was added to drinking water of poultry for 5 days. For each dose, a se...Objective: To investigate the effect of fosbac on some blood biochemical variables in broilers. Methods: Fosbac with the dose of 160 and 320 mg/kg was added to drinking water of poultry for 5 days. For each dose, a separate control group was considered. Blood samples were collected 1 day post treatment (four groups of eight 20-day-old broilers) in the first experiment, and after 7 days post treatment (another four groups of eight 20-day-old broilers) in the second experiment. The serum aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase activity, uric acid, creatinine and urea concentrations were measured using routine laboratory methods. Results: The results of this study showed that oral fosbac caused no significant effect on important liver and kidney function parameters. Conclusions: It can be concluded that this antibiotic can be used safely in broilers.展开更多
Objective:To evaluate the antiglycation and antioxidant properties of the dill tablet, an herbal product used in Iran as a hypolipidemic medicine. Methods: In this descriptive study, the antioxidant and antiradical pr...Objective:To evaluate the antiglycation and antioxidant properties of the dill tablet, an herbal product used in Iran as a hypolipidemic medicine. Methods: In this descriptive study, the antioxidant and antiradical properties of dill tablet at dif erent concentration(0.032, 0.065, 0.125, 0.25, 0.5 and 1 mg/m L) were measured. The total phenolic, l avonols and l avonoid, alkaloids, anthocyanin, tannin and saponin contents in dill tablet were determined. Furthermore, antiglycation properties of dill tablet were assayed. In the in vivo experiments, male rats were randomly divided into three groups(n = 6): Group 1: normal rats; Group 2: diabetic rats; Group 3: diabetic rats + 300 mg/kg dill tablet, and Group 4: diabetic rats + 100 mg/kg dill tablet. After 2 months, the blood glucose was measured enzymatically and advanced glycation end-products(AGEs) formation was determined using a l uorometric method.Results: Our results illustrated that different concentrations of dill tablet had significant antioxidant activity. Dill tablet markedly declined AGEs formation and fructosamine levels(P < 0.001) compared with glycated sample. Oxidation of protein carbonyl and thiol group was signii cantly reduced by dill tablet in a dose dependent manner(P < 0.001). Formation of amyloid cross-β and fragmentation were markedly inhibited by dill tablet(P < 0.001) compared with glycated sample. After 2 months, fasting blood glucose levels(P < 0.001) and AGEs formation(P < 0.05) were signii cantly reduced by dill tablet in diabetic animals. Conclusions: Dill tablet exhibited significant antiglycation and antioxidant activities. This study provides a scientii c basis for using dill in treatment of diabetic patients.展开更多
基金the Tarbiat Modares University (TMU), the Iran Mineral Processing Research Center (IMPRC) and the IMIDRO for the technical assistance and financial support
文摘As is well known to mineral processing scientists and engineers, fine and ultrafine particles are difficult to float mainly due to the low bubble-particle collision efficiencies. Though many efforts have been made to improve flotation performance of fine and ultrafine particles, there is still much more to be done. In this paper, the effects of nano-microbubbles （nanobuhbles and microbubbles） on the flotation of fine （-38 ＋ 14.36 μm） and ultrafine （-14.36 ＋ 5μm） chalcopyrite particles were investigated in a laboratory scale Denver flotation cell. Nano-microbubbles were generated using a specially-designed nano- microbubble generator based on the cavitation phenomenon in Venturi tubes. In order to better under- stand the mechanisms of nano-microbubble enhanced froth flotation of fine and ultrafine chalcopyrite particles, the nano-microbubble size distribution, stability and the effect of frother concentration on nano- bubble size were also studied by a laser diffraction method. Comparative flotation tests were performed in the presence and absence of nano-microbubbles to evaluate their impact on the fine and ultrafine chalcopyrite particle flotation recovery. According to the results, the mean size of nano-microbubbles increased over time, and decreased with increase of frother concentration. The laboratory-scale flotation test results indicated that flotation recovery of chalcopyrite fine and ultrafine particles increased by approximately 16-21% in the presence of nano-microbubbles, depending on operating conditions of the process. The presence of nano-microbubbles increased the recovery of ultrafine particles （-14.36 ＋ 5 μm） more than that of fine particles （-38 ＋ 14.36 μm）. Another major advantage is that the use of nano-microbubbles reduced the collector and frother consumptions by up to 75% and 50%, respectively.
文摘Modification and performance of Li induced silica phase transition of （Mn＋W）/SiO2 catalyst, under reaction conditions of oxidative coupling of methane （OCM）, have been investigated employing textural characterizations and redox studies. Stability and precrystalline form of fresh Li induced silica phase transition catalyst depend on the Li loading. A catalyst, with high lithium loading, destabilizes on OCM stream. This destabilization is not due to Li evaporation at OCM reaction conditions, α-cristobalite is proposed to be an intermediate in the crystallization of amorphous silica into quartz in the Li-induced silica phase transition process. However, the type of crystalline structure was found to be unimportant with regard to the formation of a selective catalyst. Metal-metal interactions of Li-Mn, Li-W and Mn-W, which are affected during silica phase crystallization, are found to be critical parameters of the trimetallic catalyst and were studied by TPR. Role of lithium in Li doped （Mn＋W）/SiO2 catalyst is described as a moderator of the Mn-W interaction by involving W in silica phase transition. These interactions help in the improvement of transition metal redox properties, especially that of Mn, in favor of OCM selectivity.
文摘In the present study,CNFs,ZnO and Al2O3 were deposited on the SMFs panels to investigate the deactivation mechanism of Pd-based catalysts in selective acetylene hydrogenation reaction.The examined supports were characterized by SEM,NH3-TPD and N2adsorption-desorption isotherms to indicate their intrinsic characteristics.Furthermore,in order to understand the mechanism of deactivation,the resulted green oil was characterized using FTIR and SIM DIS.FTIR results confirmed the presence of more unsaturated constituents and then,more branched hydrocarbons formed upon the reaction over alumina-supported catalyst in comparison with the ones supported on CNFs and ZnO,which in turn,could block the pores mouths.Besides the limited hydrogen transfer,N2 adsorption-desorption isotherms results supported that the lowest pore diameters of Al2O3/SMFs close to the surface led to fast deactivation,compared with the other catalysts,especially at higher temperatures.
基金the Tarbiat Modares University & Nuclear Science and Technology Research Institute for their financial support
文摘This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.
基金King Saud University for funding this research through Researchers Supporting Program Number(RSPD2023R704),King Saud University,Riyadh,Saudi Arabia.
文摘This research paper presents a novel optimization method called the Synergistic Swarm Optimization Algorithm(SSOA).The SSOA combines the principles of swarmintelligence and synergistic cooperation to search for optimal solutions efficiently.A synergistic cooperation mechanism is employed,where particles exchange information and learn from each other to improve their search behaviors.This cooperation enhances the exploitation of promising regions in the search space while maintaining exploration capabilities.Furthermore,adaptive mechanisms,such as dynamic parameter adjustment and diversification strategies,are incorporated to balance exploration and exploitation.By leveraging the collaborative nature of swarm intelligence and integrating synergistic cooperation,the SSOAmethod aims to achieve superior convergence speed and solution quality performance compared to other optimization algorithms.The effectiveness of the proposed SSOA is investigated in solving the 23 benchmark functions and various engineering design problems.The experimental results highlight the effectiveness and potential of the SSOA method in addressing challenging optimization problems,making it a promising tool for a wide range of applications in engineering and beyond.Matlab codes of SSOA are available at:https://www.mathworks.com/matlabcentral/fileexchange/153466-synergistic-swarm-optimization-algorithm.
文摘In the present study,a novel approach based on an evolutionary wavelet neural network(EWNN)is proposed to estimate the slag quality in an electric arc furnace(EAF)employing power quality indices.In the EWNN,an evolutionary method is applied to train the parameters for a combination of neural networks and wavelets.I For this purpose,all of the electrical parameters for six melting processes are measured with a power quality analyzer,attached to the secondary component of an EAF transformer at a Saba steel complex,to estimate the foaming slag quality.Experimental results on various combinations of measured electrical parameters,applying the designed EWNN estimator,demonstrate that utilizing five leading indicators leads to the highest precision.The obtained 99%accuracy for estimating the foaming slag quality by EWNN compared to the other methods illustrates the proposed method's efficiency.
文摘The effects of manganese oxide or ceria promoters on the performance of Na2WO4/SiO2 catalysts for oxidative coupling of methane （OCM） are reported. The OCM reaction was performed in a continuous-flow microreactor at 800℃, atmospheric pressure and under GHSV = 13200 ml·gCat^-1·h^-1.Catalysts were characterized by in situ conductivity measurement, FT-IR spectroscopy, XRD, SEM and temperature programmed reduction analysis. Manganese oxide promoted Na2WO4/SiO2 is considered as one of the active and selective catalysts for OCM reaction. Ceria with high oxygen storage capacity is selected as a proper oxygen activator, providing a higher concentration of the oxy-anion species which is suitable for OCM reaction and compared with manganese oxide. Electrical conductivity of the catalysts was measured in OCM reaction under oxidizing atmosphere, i.e. in the absence of methane. It was found that the trimetallic catalysts, i.e. the catalysts having sodium, tungsten and Mn or Ce species, exhibited similar crystalline structures and morphologies, which lead to suitable bulk properties for the formation of an active and selective catalyst. However, tungsten had significant effect on the texture and redox properties of the catalysts. It was also shown that the crystalline structure of the bimetallic （Na＋Mn or Ce）/SiO2 samples was quite different. This reveals that the metal oxides have significant effect on the extent of crystallization, taking place in the course of interaction of sodium with silica support. Similar conductivities and catalytic performances of （Na2WO4＋Mn or Ce）/SiO2 catalysts propose that the ability of Na2WO4/SiO2 for utilizing oxy-anions formed in presence of different metal oxides is limited.
文摘Utilizing the phase change materials in different thermal storage applications attains valuable attention due to the fascinating thermal properties of these materials.The comprehension of the thermal behaviour of phase change materials during the melting and solidification is considered a significant priority in designing the shape of the different containers.In this review,analytical,computational and experimental investigations that address solidification/freezing of phase change materials within thermal energy storage systems are discussed.Emphasis is placed on the role of the shape of adopted containers encompassing planar,spherical,cylindrical and annular vessels.Energy storage for solar thermal applications,waste heat recovery,and thermal management of buildings/computing platforms/photovoltaics has been the topics that benefit from these investigations.For all container shapes,the freezing process is controlled initially by natural convection,and a high solidification rate is observed.Later,the conduction dominates the process,and the freezing rate declines.The temperature and flow of cooling heat transfer fluid affect the solidification process,but the impact of heat transfer fluid temperature is more significant than its flow rate.Also,the freezing time increases with the container’s size and amount of contained PCM.The aspect ratio of the planar and vertical cylindrical cavities substantially influences the discharging time and rate.In contrast,the orientation of the annular cavity has a lower impact on the discharging process.
基金supported by Iran National Science Foundation(No.97015707)。
文摘A series of organic compounds were successfully immobilized on an N-doped graphene quantum dot (N-GQD) to prepare a multifunctional organocatalyst for coupling reaction between CO_(2)and propylene oxide (PO).The simultaneous presence of halide ions in conjunction with acidic-and basic-functional groups on the surface of the nanoparticles makes them highly active for the production of propylene carbonate (PC).The effects of variables such as catalyst loading,reaction temperature,and structure of substituents are discussed.The proposed catalysts were characterized by different techniques,including Fourier transform infrared spectroscopy (FTIR),field emission scanning electron microscopy/energy dispersive X-ray microanalysis (FESEM/EDX),thermogravimetric analysis (TGA),elemental analysis,atomic force microscopy (AFM),and ultraviolet–visible (UV-Vis) spectroscopy.Under optimal reaction conditions,3-bromopropionic acid (BPA) immobilized on N-GQD showed a remarkable activity,affording the highest yield of 98%at 140℃ and 106Pa without any co-catalyst or solvent.These new metal-free catalysts have the advantage of easy separation and reuse several times.Based on the experimental data,a plausible reaction mechanism is suggested,where the hydrogen bonding donors and halogen ion can activate the epoxide,and amine functional groups play a vital role in CO_(2)adsorption.
基金partially funded by Agrilac Resiliente and by Mitig ate+:Research for Low-Emission Food Systemsfunded by the project 18_Ⅲ_106_COL_A_Sustainable productive strategies
文摘As the COVID-19 pandemic unfolded,questions arose as to whether the pandemic would amplify or pacify tropical deforestation.Early reports warned of increased deforestation rates;however,these studies were limited to a few months in 2020 or to selected regions.To better understand how the pandemic infl uenced tropical deforestation globally,this study used historical deforestation data(2004–2019)from the Terra-i pantropical land cover change monitoring system to project expected deforestation trends for 2020,which were used to determine whether observed deforestation deviated from expected trajectories after the fi rst COVID-19 cases were reported.Time series analyses were conducted at the regional level for the Americas,Africa and Asia and at the country level for Brazil,Colombia,Peru,the Democratic Republic of Congo and Indonesia.Our results suggest that the pandemic did not alter the course of deforestation trends in some countries(e.g.,Brazil,Indonesia),while it did in others(e.g.,Peru).We posit the importance of monitoring the long-term eff ects of the pandemic on deforestation trends as countries prioritize economic recovery in the aftermath of the pandemic.
文摘Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pretreatment steps (reduction and activation) and their effect on catalytic performance for iron based catalysts.In this study,Fe-Cu-La-SiO2 catalysts were prepared by co-precipitation method.To investigate the intraparticle mass transfer limitation under reduction,activation and reaction steps,and its effect on catalytic performance,catalyst pellets with different sizes of 6,3,1 and 0.5 mm have been prepared.All catalysts were calcined,pretreated and tested under similar conditions.The catalysts were activated in hydrogen (5%H2in N2) at 450℃ for 3 h and exposed to syngas (H2/CO=1) at 270℃ and atmospheric pressure for 40 h.Afterwards,FTS reaction tests were performed for approximately 120 h to reach steady state conditions at 290℃,17 bar and a feed flow (syngas H2/CO=1) rate of 3 L/h (STP).Using small pellets resulted in higher CO conversion,FT reaction rate and C5+ productivity as compared with larger pellets.The small pellets reached steady state conditions just 20 h after starting the reaction.Whereas for larger pellets,CO conversion,FT reaction rate and C5+ productivity increased gradually,and reached steady state and maximum values after 120 h of operation.The results illustrate that mass transfer limitations exist not only for FTS reaction but also for the reduction and carburization steps which lead to various phase formation through catalyst activation.Also the results indicate that some effects of mass transfer limitations in activation step,can be compensated in the reaction step.The results can be used for better design of iron based catalyst to improve the process economy.
文摘This paper uses the Butterfly Optimization Algorithm(BOA)with dominated sorting and crowding distance mechanisms to solve multi-objective optimization problems.There is also an improvement to the original version of BOA to alleviate its drawbacks before extending it into a multi-objective version.Due to better coverage and a well-distributed Pareto front,non-dominant rankings are applied to the modified BOA using the crowding distance strategy.Seven benchmark functions and eight real-world problems have been used to test the performance of multi-objective non-dominated advanced BOA(MONSBOA),including unconstrained,constrained,and real-world design multiple-objective,highly nonlinear constraint problems.Various performance metrics,such as Generational Distance(GD),Inverted Generational Distance(IGD),Maximum Spread(MS),and Spacing(S),have been used for performance comparison.It is demonstrated that the new MONSBOA algorithm is better than the compared algorithms in more than 80%occasions in solving problems with a variety of linear,nonlinear,continuous,and discrete characteristics based on the Pareto front when compared quantitatively.From all the analysis,it may be concluded that the suggested MONSBOA is capable of producing high-quality Pareto fronts with very competitive results with rapid convergence.
基金Supported by the simulation of Nano Physics Lab center of Kermanshah Branch,Islamic Azad University
文摘By FP-LAPW calculations, the structural, elastic, Debye and Curie temperatures, electronic and magnetic properties of Co2 VAl are investigated. The results indicate that Ferromagnetic （FM） phase is more stable than Anti- Ferromagnetic （AFM） and Non-magnetic （NM） ones. In addition, C11-C12 〉 0, C44 〉 0, and B 〉 0 so Co2 VAl is an elastically stable material with high Debye temperature. Also, the BIG ratio exhibits a ductility behavior. The relatively high Curie temperature provides it as a favorable material for spintronic application. It＇s electronic and magnetic properties are studied by GGA ＋U approach leading to a 100% spin polarization at Fermi level.
文摘Accelerated deactivation of ruthenium-promoted alumina-supported alkalized cobalt （K-Ru-Co/γ-Al 2 O 3 ） Fischer-Tropsch （FT） synthesis catalyst along the catalytic bed over 120 h of time-on-stream （TOS） was investigated. Catalytic bed was divided into three parts and structural changes of the spent catalysts collected from each catalytic bed after FT synthesis were studied using different techniques. Rapid deactivation was observed during the reaction due to high reaction temperature and low feed flow rates. The physico-chemical properties of the catalyst charged in the Bed #1 of the reactor did not change significantly. Interaction of cobalt with alumina and the formation of CoAl 2 O 4 increased along the catalytic bed. Reducibility percentage decreased by 4.5%, 7.5% and 12.9% for the catalysts in the Beds #1, #2 and #3, respectively. Dispersion decreased by 8.8%, 14.4% and 26.6% for the catalysts in the Beds #1, #2 and #3, respectively. Particle diameter increased by 0.6%, 2.4% and 10.4% for the catalysts in the Beds #1, #2 and #3, respectively, suggesting higher rate of sintering at the last catalytic bed. The amount of coke at the last catalytic bed was significantly higher than those of Beds #1 and #2.
文摘Managing physical objects in the network’s periphery is made possible by the Internet of Things(IoT),revolutionizing human life.Open attacks and unauthorized access are possible with these IoT devices,which exchange data to enable remote access.These attacks are often detected using intrusion detection methodologies,although these systems’effectiveness and accuracy are subpar.This paper proposes a new voting classifier composed of an ensemble of machine learning models trained and optimized using metaheuristic optimization.The employed metaheuristic optimizer is a new version of the whale optimization algorithm(WOA),which is guided by the dipper throated optimizer(DTO)to improve the exploration process of the traditionalWOA optimizer.The proposed voting classifier categorizes the network intrusions robustly and efficiently.To assess the proposed approach,a dataset created from IoT devices is employed to record the efficiency of the proposed algorithm for binary attack categorization.The dataset records are balanced using the locality-sensitive hashing(LSH)and Synthetic Minority Oversampling Technique(SMOTE).The evaluation of the achieved results is performed in terms of statistical analysis and visual plots to prove the proposed approach’s effectiveness,stability,and significance.The achieved results confirmed the superiority of the proposed algorithm for the task of network intrusion detection.
基金This study has received financial support from the Vice Chancellor for Research&Technology Affairs,Shiraz University of Medical Sciences(Grant number:26817).
文摘Objective:Pneumocystis pneumonia(PcP)is a life-threatening infection caused by the opportunistic fungi Pneumocystis jirovecii.The emergence of the COVID-19 pandemic forced the focus of attention of health policymakers on these two infections due to their clinical and paraclinical similarities,which cause diagnostic dilemmas.This study was undertaken to evaluate and estimate the global prevalence and main leading risk factors of coronavirus-associated pneumocystosis(CAP).Methods:We searched related databases between December 2019 and May 2022 for studies reporting CAP.Meta-analysis was performed using StatsDirect software(version 2.7.9)according to the DerSimonian and Laird method applying the random-effects model.We evaluated heterogeneity using theχ2-based Q statistic(significant for P<0.05)and the I2 statistic(>75%indicative of“notable”heterogeneity).Moreover,an odds ratio(OR)analysis was performed for eligible data.Results:Our meta-analysis included eight studies with 923 patients hospitalized with COVID-19;among them,92 were PcP cases.The overall pooled prevalence of CAP was estimated at 11.5%.The mortality among CAP patients was lower than that of non-PcP patients(OR 1.93;95%CI 0.86-4.31).Long-term corticosteroid therapy(OR 28.22;95%CI 0.54-1480.84)was the most predisposing factor for PcP among COVID-19 patients,followed by pulmonary diseases(OR 1.46;95%CI 0.43-4.98),kidney diseases(OR 1.26;95%CI 0.21-7.49),and acute respiratory destruction syndrome(OR 1.22;95%CI 0.05-29.28).Conclusions:The prevalence of PcP among the COVID-19 population is almost similar to the pre-COVID era.However,PcP-related mortality was decreased by the emergence of the COVID-19 pandemic.Women with COVID-19 are more susceptible to PcP than men.Acute respiratory distress syndrome,kidney diseases,pulmonary diseases,and long-term corticosteroid therapy increased the risk of PcP;however,transplantation and malignancy decreased the risk for PcP among COVID-19 patients.Further retrospective,case-control,prospective,and more precisely sy
文摘Thin films produced by electrostatic spray deposition （ESD） have nanometer-sized structures despite the initial sprayed droplets being typically a few tens of microns in diameter. The size and morphology of the resulting structures is not only affected by the solvent properties and drying kinetics, hut also by Coulomb fission owing to the high surface charge density that the droplets build up upon evaporation. In this work we modulate the charge density of the droplets by inducing ionic wind along the spray, and produce mesoscopic structures. Using WO3 as an example, we show that the technique provides a practical way to control the morphology of thin films produced by ESD.
基金financially supported by the Hamadan University of Medical Sciences(No 9603302213)
文摘Objective:To evaluate the effect of resveratrol against CCl4-induced nephrotoxicity.Methods:Forty-two male Wistar rats were divided into seven groups randomly.After six weeks,kidney weight,body weight,blood urea,serum creatinine,oxidative stress markers,and gene expression of renal transforming growth factor-beta1(TGF-β1),TGF-βreceptor type 1(TGF-βR1)and Smad3 were determined.In addition,the protein level of TGF-β1 in the tissue lysate was measured.Results:Resveratrol had a protective role in renal tissue by the improvement of antioxidant balance and reduction of renal parameters such as creatinine and urea(P<0.001).In addition,the renal m RNA level of TGF-β1,TGF-βR1,Smad3,as well as the protein level of TGF-β1 were decreased in rats treated with resveratrol(P<0.001),compared to the CCl4 group.Conclusions:Overall,resveratrol shows a protective effect against nephrotoxicity in CCl4 treated rats by reducing oxidative stress status and modulating the TGF-βsignaling.
文摘Objective: To investigate the effect of fosbac on some blood biochemical variables in broilers. Methods: Fosbac with the dose of 160 and 320 mg/kg was added to drinking water of poultry for 5 days. For each dose, a separate control group was considered. Blood samples were collected 1 day post treatment (four groups of eight 20-day-old broilers) in the first experiment, and after 7 days post treatment (another four groups of eight 20-day-old broilers) in the second experiment. The serum aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase activity, uric acid, creatinine and urea concentrations were measured using routine laboratory methods. Results: The results of this study showed that oral fosbac caused no significant effect on important liver and kidney function parameters. Conclusions: It can be concluded that this antibiotic can be used safely in broilers.
基金Supported by Hamadan University of Medical Sciences,Hamadan,Iran(Grant No.930126463)
文摘Objective:To evaluate the antiglycation and antioxidant properties of the dill tablet, an herbal product used in Iran as a hypolipidemic medicine. Methods: In this descriptive study, the antioxidant and antiradical properties of dill tablet at dif erent concentration(0.032, 0.065, 0.125, 0.25, 0.5 and 1 mg/m L) were measured. The total phenolic, l avonols and l avonoid, alkaloids, anthocyanin, tannin and saponin contents in dill tablet were determined. Furthermore, antiglycation properties of dill tablet were assayed. In the in vivo experiments, male rats were randomly divided into three groups(n = 6): Group 1: normal rats; Group 2: diabetic rats; Group 3: diabetic rats + 300 mg/kg dill tablet, and Group 4: diabetic rats + 100 mg/kg dill tablet. After 2 months, the blood glucose was measured enzymatically and advanced glycation end-products(AGEs) formation was determined using a l uorometric method.Results: Our results illustrated that different concentrations of dill tablet had significant antioxidant activity. Dill tablet markedly declined AGEs formation and fructosamine levels(P < 0.001) compared with glycated sample. Oxidation of protein carbonyl and thiol group was signii cantly reduced by dill tablet in a dose dependent manner(P < 0.001). Formation of amyloid cross-β and fragmentation were markedly inhibited by dill tablet(P < 0.001) compared with glycated sample. After 2 months, fasting blood glucose levels(P < 0.001) and AGEs formation(P < 0.05) were signii cantly reduced by dill tablet in diabetic animals. Conclusions: Dill tablet exhibited significant antiglycation and antioxidant activities. This study provides a scientii c basis for using dill in treatment of diabetic patients.
