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Synergistic effect of adsorption and photocatalytic degradation of oilfield-produced water by electrospun photocatalytic fibers of Polystyrene/Nanorod-Graphitic carbon nitride

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Journal of Environmental Sciences 2024年第7期141卷 287-303页

作者： Parisa Azmoon Mehrdad Farhadian Alireza Pendashteh Amir H.Navarchian Department of Chemical engineering Faculty of EngineeringUniversity of IsfahanIsfahanIran Department of Chemical engineering Faculty of EngineeringUniversity of GuilanRashtIran Department of Water and Environmental engineering Caspian Sea Basin Research CenterUniversity of GuilanRashtIran

Graphitic carbon nitride with nanorod structure(Nr-GCN)was synthesized using melamine as a precursor without any other reagents by hydrothermal pretreatment method.XRD,FTIR,SEM,N_(2)adsorption-desorption from BET,UV-Vis DRS spectroscopy,and photoluminescence were used to characterize the prepared samples.Also,the photoelectrochemical behavior of nanoparticles was studied by photocurrent transient response and cyclic voltammetry analysis.Polystyrene(PS)fibrous mat was fabricated by electrospinning technique and used as a support for the stabilization of the nanoparticles.The performance of the synthesized nanoparticles and photocatalytic fibers(PS/Nr-GCN)was evaluated in oilfield-produced water treatment under visible light irradiation.During this process,oil contaminants were adsorbed by hydrophobic polystyrene fibers and simultaneously degraded by Nr-GCN.The removal efficiency of chemical oxygen demand(COD)has been obtained 96.6%and 98.4%by Nr-GCN and PS/Nr-GCN,respectively,at the optimum conditions of pH4,photocatalyst dosage 0.5 g/L,COD initial concentration 550 mg/L,and illumination time 150 min.The gas chromatography-mass spectroscopy analysis results showed 99.3%removal of total petroleum hydrocarbons using photocatalytic fibers of PS/Nr-GCN.The results demonstrated that the GCN has outstanding features like controllable morphology,visible-light-driven,and showing high potential in oily wastewater remediation.Moreover,the synergistic effect of adsorption and photocatalytic degradation is an effective technique in oilfield-produced water treatment.

关键词： Graphitic carbon nitride(GCN) Nanorod structure Polystyrene fibrous mat Photocatalytic fibers Oilfield-produced water(OPW)

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Automated evaluation of parapapillary choroidal microvasculature in crowded optic discs:a controlled,optical coherence tomography angiography study

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International Journal of Ophthalmology(English edition) 2024年第1期17卷 113-118页

作者： Hatice Arda Hidayet Sener Ozge Temizyurek Hatice Kubra Sonmez Duygu Gulmez Sevim Cem Evereklioglu Fatih Horozoglu Ayse Busra Gunay Sener Department of Ophthalmology Erciyes University Medical FacultyKayseri 38090Turkey Department of Medical informatics and Biostatistics Erciyes University Medical FacultyKayseri 38090Turkey

AIM:To compare superficial and deep vascular properties of optic discs between crowded discs and controls using optical coherence tomography angiography(OCT-A).METHODS:Thirty patients with crowded discs,and 47 control subjects were enrolled in the study.One eye of each individual was included and OCT-A scans of optic discs were obtained in a 4.5×4.5 mm^(2) rectangular area.Radial peripapillary capillary(RPC)density,peripapillary retinal nerve fiber layer(pRNFL)thickness,cup volume,rim area,disc area,cup-to-disc(c/d)area ratio,and vertical c/d ratio were obtained automatically using device software.Automated parapapillary choroidal microvasculature(PPCMv)density was calculated using MATLAB software.When the vertical c/d ratio of the optic disc was absent or small cup,it was considered as a crowded disc.RESULTS:The mean signal strength index of OCT-A images was similar between the crowded discs and control eyes(P=0.740).There was no difference in pRNFL between the two groups(P=0.102).There were no differences in RPC density in whole image(P=0.826)and peripapillary region(P=0.923),but inside disc RPC density was higher in crowded optic discs(P=0.003).The PPCMv density in the inner-hemisuperior region was also lower in crowded discs(P=0.026).The pRNFL thickness was positively correlated with peripapillary RPC density(r=0.498,P<0.001).The inside disc RPC density was negatively correlated with c/d area ratio(r=-0.341,P=0.002).CONCLUSION:The higher inside disc RPC density and lower inner-hemisuperior PPCMv density are found in eyes with crowded optic discs.

关键词： crowded optic disc ischemic optic neuropathy optical coherence tomography angiography parapapillary choroidal microvasculature

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Inherently Sinusoidal Single-phase Voltage Source Inverter Based on Modified Cuk Cell

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Chinese Journal of Electrical engineering 2024年第1期10卷 114-123页

作者： Misbahul Munir Wisyahyadi Arwindra Rizqiawan Jihad Furqani School of Electrical engineering and informatics Bandung Institute of TechnologyBandung 40132Indonesia

Renewable energy has become important for electricity generation because of the high air pollution associated with conventional fossil-based energy systems.Conventional fossil-based power plants are gradually transitioning by incorporating renewable energy sources,such as photovoltaic(PV)cells.In a PV system,an inverter converts DC power from solar panels to AC power required to serve common electrical loads.A conventional H-bridge inverter topology has several disadvantages,such as the voltage being not sinusoidal,switching the DC voltage and high common-mode voltage.The common-mode voltage can cause a large leaked capacitive current,which can result in undesirable operation in solar power applications.A common solution to this problem is the addition of a large filter to the input or output of an inverter.An inherent sinusoidal voltage source inverter based on a modified Cuk converter as its basic cell,which simultaneously generates a sinusoidal output voltage and a lower common-mode voltage,is proposed.The proposed topology does not require additional input or output filters.Analytical expressions are derived to confirm the operation of the proposed topology.Simulation results confirm the mathematical analysis.A laboratory-scale experiment is performed to verify the proposed inverter.

关键词： Voltage source inverter common-mode voltage capacitive current modified Cuk converter and sinusoidal waveform

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Sequential alkaline-organic acid leaching process to enhance the recovery of rare earth elements from Indonesian coal fly ash

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Journal of Rare Earths 2024年第7期42卷 1366-1374页

作者： Widya Rosita Indra Perdana I Made Bendiyasa Ferian Anggara Himawan Tri Bayu Murti Petrus Agus Prasetya Isyatun Rodliyah Department of Nuclear engineering and engineering Physics Faculty of EngineeringUniversitas Gadjah Mada Department of Chemical engineering Faculty of EngineeringUniversitas Gadjah Mada Department of Geological engineering Faculty of EngineeringUniversitas Gadjah Mada Unconventional Geo-resources Research Group Faculty of EngineeringUniversitas Gadjah Mada Center for Testing of Mineral and Coal Tekmira-Directorate General of Mineral and Coal-Ministry of Energy and Mineral Resources

In this decade,coal fly ash(CFA) is considered a potential secondary source of rare earth elements(REEs).However,most REEs in coal fly ash are encapsulated in aluminosilicate glass,making it challenging to recover them through acid leaching.In this study,a sequential alkaline-organic acid leaching was developed for the recovery of REEs from CFA.The effect of alkaline leaching using NaOH solution on the destructive ability of aluminosilicate glass,as well as the mineralogy and morphology changes of the resulting coal fly ash,was first studied.Furthermore,the effectiveness of alkaline leaching on the recovery ability of REEs through organic acid leaching was evaluated.The results show that the maximum leaching efficiency for Si and Al,which was obtained at the optimum alkaline leaching conditions,namely NaOH concentration of 10 mol/L,reaction temperature of 65℃,liquid/solid(L/S) ratio of 10 mL/g,and reaction time of 90 min,is 28% and 32%,respectively.The digestion reaction with NaOH lixiviants also causes coal fly ash to become more porous,making it advantageous in the organic acid-leaching process at the REEs recovery stage.The utilization of the desilicated residue produced from the digestion process in acid leaching effectively increases the overall REEs recovery from 32.2% to 77.6%.

关键词： Alkaline Coal fly ash Organic acid Rare earth elements

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Compression properties of cost-efficient porous expanded clay reinforced AA7075 syntactic foams fabricated by industrial-oriented die casting technology

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China Foundry 2024年第1期21卷 60-70页

作者： İsmail Cem Akgün Çağın Bolat Ali Gökşenli faculty of Mechanical engineering Istanbul Technical University34437İstanbulTurkey faculty of engineering Samsun University55420SamsunTurkey

In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and anti-pollution.At this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a problem-solver.Owing to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors nowadays.In this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF studies.Additionally,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive responses.Attained results show that PEC particles can be an alternative to expensive hollow spheres used in the previous works.Besides,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength.

关键词： die casting porous materials metal matrix sytanctic foams expanded clay compressive deformation

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Nonlinear phenomena in vibrations of embedded carbon nanotubes conveying viscous fluid

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Nanotechnology and Precision engineering 2024年第1期7卷 44-54页

作者： Reza Ebrahimi Mechanical engineering Faculty of EngineeringYasouj UniversityYasouj 75918-74831Iran

Various nonlinear phenomena such as bifurcations and chaos in the responses of carbon nanotubes(CNTs)are recognized as being major contributors to the inaccuracy and instability of nanoscale mechanical systems.Therefore,the main purpose of this paper is to predict the nonlinear dynamic behavior of a CNT conveying viscousﬂuid and supported on a nonlinear elastic foundation.The proposed model is based on nonlocal Euler–Bernoulli beam theory.The Galerkin method and perturbation analysis are used to discretize the partial differential equation of motion and obtain the frequency-response equation,respectively.A detailed parametric study is reported into how the nonlocal parameter,foundation coefﬁcients,ﬂuid viscosity,and amplitude and frequency of the external force inﬂuence the nonlinear dynamics of the system.Subharmonic,quasi-periodic,and chaotic behaviors and hardening nonlinearity are revealed by means of the vibration time histories,frequency-response curves,bifurcation diagrams,phase portraits,power spectra,and Poincarémaps.Also,the results show that it is possible to eliminate irregular motion in the whole range of external force amplitude by selecting appropriate parameters.

关键词： Nonlinear vibration Carbon nanotubes Nonlocal effect Viscousﬂuid Nonlinear elastic medium

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Graphene oxide-coated microbottle resonators for relative humidity sensing

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Optoelectronics Letters 2024年第7期20卷 400-405页

作者： Huda Adnan Zain Malathy Batumalay Md Ashadi Md Johari Hazli Rafis Abdul Rahim Sulaiman Wadi Harun Department of Electrical engineering Faculty of Engineering University of Malaya faculty of Data Science and Information Technology INTI International University faculty of Electrical and Electronic engineering Technology Universiti Teknikal Malaysia Melaka faculty of Electronic and Computer engineering Universiti Teknikal Malaysia Melaka

Graphene oxide(GO) is a 2D coating material used to improve fiber optics sensors' response to relative humidity. Microbottle resonators(MBRs) have garnered more attention as sensing media structures. An MBR with a 190 μm diameter was coated with GO. Then, tapered fiber light coupling was used to investigate the relative humidity sensing performance in the range of 35—70%RH at 25 °C. The MBR showed a higher Q factor before and after GO coating. The sensitivity of 0.115 d B/%RH was recorded with the 190 μm GO-coated MBR sample compared to a sensitivity of 0.022 d B/%RH for the uncoated MBR sample. These results show that the MBR can be used in fiber optic sensing applications for environmental sensing.

关键词： A

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Dynamics of a rotating ring-stiffened sandwich conical shell with an auxetic honeycomb core

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 963-982页

作者： S.JAHANGIRI A.GHORBANPOUR ARANI Z.KHODDAMI MARAGHI Department of Solid Mechanics Faculty of Mechanical EngineeringUniversity of KashanKashan ***Iran faculty of engineering Mahallat Institute of Higher EducationMahallat ***Iran

The free vibration analysis of a rotating sandwich conical shell with a reentrant auxetic honeycomb core and homogenous isotropic face layers reinforced with a ring support is studied.The shell is modeled utilizing the first-order shear deformation theory(FSDT)incorporating the relative,centripetal,and Coriolis accelerations alongside the initial hoop tension created by the rotation.The governing equations,compatibility conditions,and boundary conditions are attained using Hamilton’s principle.Utilizing trigonometric functions,an analytical solution is derived in the circumferential direction,and a numerical one is presented in the meridional direction via the differential quadrature method(DQM).The effects of various factors on the critical rotational speeds and forward and backward frequencies of the shell are studied.The present work is the first theoretical work regarding the dynamic analysis of a rotating sandwich conical shell with an auxetic honeycomb core strengthened with a ring support.

关键词： free vibration conical shell rotating shell ring support auxetic honeycomb

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Hydrodynamic function and spring constant calibration of FluidFM micropipette cantilevers

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Microsystems & Nanoengineering 2024年第1期10卷 277-286页

作者： Attila Bonyár Ágoston G.Nagy Hans Gunstheimer Gotthold Fläschner Robert Horvath Department of Electronics Technology Faculty of Electrical Engineering and InformaticsBudapest University of Technology and EconomicsBudapestHungary Nanobiosensorics Laboratory Institute of Technical Physics and Materials ScienceCentre for Energy ResearchHUN-RENBudapestHungary Nanosurf AG Gräubernstrasse 12CH-4410 LiestalSwitzerland

Fluidic force microscopy(FluidFM)fuses the force sensitivity of atomic force microscopy with the manipulation capabilities of microfluidics by using microfabricated cantilevers with embedded fluidic channels.This innovation initiated new research and development directions in biology,biophysics,and material science.To acquire reliable and reproducible data,the calibration of the force sensor is crucial.Importantly,the hollow FluidFM cantilevers contain a row of parallel pillars inside a rectangular beam.The precise spring constant calibration of the internally structured cantilever is far from trivial,and existing methods generally assume simplifications that are not applicable to these special types of cantilevers.In addition,the Sader method,which is currently implemented by the FluidFM community,relies on the precise measurement of the quality factor,which renders the calibration of the spring constant sensitive to noise.In this study,the hydrodynamic function of these special types of hollow cantilevers was experimentally determined with different instruments.Based on the hydrodynamic function,a novel spring constant calibration method was adapted,which relied only on the two resonance frequencies of the cantilever,measured in air and in a liquid.Based on these results,our proposed method can be successfully used for the reliable,noise-free calibration of hollow FluidFM cantilevers.

关键词： spring cantilever function

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Challenges and opportunities in the production of magnesium parts by directed energy deposition processes

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Journal of Magnesium and Alloys 2024年第5期12卷 1663-1686页

作者： Gürel ?am Ali Günen Iskenderun Technical University Faculty of Engineering and Natural Sciences Department of Mechanical Engineering Iskenderun Technical University Faculty of Engineering and Natural Sciences Department of Metallurgy and Materials Engineering

Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight, high specific strength,and corrosion resistance, making them attractive for applications in medical, aerospace, automotive, and other transport industries. However,their widespread application is hindered by their low formability at room temperature due to limited slip systems. Cast Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high scrap. While casting methods benefit from established process optimization techniques for these problems, additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain applications.Although metal additive manufacturing(MAM) technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts, they in general exhibit superior properties than the cast counterparts. Thus, MAM is a promising technique to produce Mg alloy parts. Directed energy deposition processes, particularly wire arc directed energy deposition(WA-DED), have emerged as an advantageous additive manufacturing(AM) technique for metallic materials including magnesium alloys, offering advantages such as high deposition rates, improved material efficiency, and reduced production costs compared to subtractive processes. However, the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation, pose unique hurdles in the application of this technology.This review paper delves into the progress made in the application of DED technology to Mg-alloys, its challenges, and prospects.Furthermore, the predominant imperfections, notably inhomogeneous microstructur

关键词： Additive manufacturing DED processes Arc-DED Wire arc additive manufacturing (WAAM) 3-D printing High deposition rate

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