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A screen-printed, amperometric biosensor for the determination of organophosphorus pesticides in water samples

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Journal of Environmental Sciences 2012年第5期24卷 956-962页

作者： raju Sekar Department of Biological Sciences Xi'an Jiaotong-Liverpool University

An amperometric biosensor based on screen-printed electrodes （SPEs） was developed for the determination of organophosphorus pesticides in water samples. The extent of acetylcholinesterase （AChE） deactivation was determined and quantified for pesticide concentrations in water samples. An enzyme immobilization adsorption procedure and polyacrylamide gel matrix polymerization were used for fabrication of the biosensor, with minimal losses in enzyme activity. The optimal conditions for enzyme catalytic reaction on the SPEs surfaces were acetylthiocholine chloride （ATChCl） concentration of 5 mmol/L, pH 7 and reaction time of 4 min. The detection limits for three organophosphorus pesticides （dichlorvos, monocrotophs and parathion） were in the range of 4 to 7 μg/L when an AChE amount of 0.1 U was used for immobilization.

关键词： organophosphorus pesticides acetylcholinesterase enzyme immobilization screen-printed electrodes biosensor

Kinetic simulation of an electronegative plasma with a cut-off distribution and modified Bohm criterion

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Plasma Science and Technology 2020年第4期22卷 33-39页

作者： Suresh BASNET raju KHANAL Central Department of Physics Tribhuvan UniversityKirtipurKathmandu 44613Nepal

A kinetic simulation model has been employed to study the properties of an electronegative magnetized plasma sheath assuming the cut-off distribution of electrons and negative *** fundamental kinetic Bohm condition for the electronegative magnetized plasma has paramount importance for the formation of a stationary plasma sheath near the material *** presence of an oblique magnetic field in an electronegative plasma affects the ion distribution at the plasma injection side and at the *** temperature profile of negative charged particles has a non-uniform distribution,which determines the energy flow towards the wall.

关键词： Bohm condition kinetic simulation plasma–wall interaction electronegative plasma

Enhancement of Solar PV Panel Efficiency Using Double Integral Sliding Mode MPPT Control

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Tsinghua Science and Technology 2024年第1期29卷 271-283页

作者： Immadisetty Rahul raju Hariharan Department of Electrical and Electronics Engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical Sciences(SIMATS)Chennai 602105India

The extraction of maximum power from the solar panels,using the sliding mode control scheme,becomes popular for partial weather atmospheric conditions due to its effective dynamic duty cycle ***,the sliding mode control scheme was sophisticated with single integral and double integral sliding mode control scheme,which offer enhanced maximum power extraction and support enhanced solar panel efficiency in partial weather *** operation of the sliding mode control scheme depends on the selection of a sliding surface selection based on the atmospheric weather condition,which enables the effective sliding duty cycle ratio operation for the DC/DC boost *** duty cycle ratio of the sliding mode control resembles the usual dynamic behavior to achieve enhanced efficiency compared to the various maximum power point tracking(MPPT)*** major limitation of the sliding mode control scheme is to achieve the steady state voltage error of the solar panel in minimum settling time *** single integral sliding mode control scheme achieves the expected steady state voltage error limit but fails to achieve minimum settling time ***,the single integral sliding mode control is extended to a double integral sliding mode control scheme to achieve both steady state voltage error limits within the minimum settling time *** double integral sliding mode control scheme allows us to obtain the higher sliding surface duty cycle ratio which acts as the input signal to the boost *** activates the enhanced stable and reliable system operation,and nullifies the lacuna of maximum solar panel efficiency under partial weather ***,this paper aims to present the design and performance operation of the double integral sliding mode(DISM)MPPT control *** validate the performance analysis of the proposed DISM MPPT control scheme,the MATLAB/Simulink model is designed and ***,the performance analysis of the pr

关键词： maximum power point tracking(MPPT)schemes sliding mode controller(SMC) double integral sliding mode controller(DISMC) pulse width modulation(PWM) photovoltaic(PV)system

Azoxymethane-induced rat aberrant crypt foci:Relevance in studying chemoprevention of colon cancer

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World Journal of Gastroenterology 2008年第43期14卷 6632-6635页

作者： Jayadev raju Toxicology Research Division Bureau of Chemical SafetyFood DirectorateHealth CanadaOttawaK1A 0L2OntarioCanada

The pathogenesis of colon cancer involves sequential and multistep progression of epithelial cells initiated to a cancerous state with defined precancerous intermediaries. Aberrant crypt foci （ACF） represent the earliest identifiable intermediate precancerous lesions during colon carcinogenesis in both laboratory animals and humans. ACF are easily induced by colon-specific carcinogens in rodents and can be used to learn more about the process of colon carcinogenesis. For over two decades, since its first discovery, azoxymethane （AOM）-induced rodent ACF have served as surrogate biomarkers in the screening of various anticarcinogens and carcinogens. Several dietary constituents and phytochemicals have been tested for their colon cancer chemopreventive efficacy using the ACF system. There has been substantial effort in defining and refining ACF in terms of understanding their molecular make-up, and extensive research in this field is currently in progress. In chemoprevention studies, AOM-induced rat ACF have been very successful as biomarkers, and have provided several standardized analyses of data. There have been several studies that have reported that ACF data do not correlate to actual colon tumor outcome, however, and hence there has been an ambiguity about their role as biomarkers. The scope of this mini-review is to provide valuable insights and limitations of AOM-induced rat ACF as biomarkers in colon cancer chemoprevention studies. The role of the dynamics and biological heterogeneity of ACF is critical in understanding them as biomarkers in chemoprevention studies.

关键词： Aberrant crypt foci Azoxymethane Biological markers Carcinogenesis Chemoprevention Colon cancer

Assessment of Cross-coupling Effects in PV String-integrated-converters with P&O MPPT Algorithm Under Various Partial Shading Patterns

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CSEE Journal of Power and Energy Systems 2022年第4期8卷 1013-1028页

作者： Suneel raju Pendem Suresh Mikkili the Electrical and Electronics Engineering Department National Institute of Technology GoaPonda 403401India

A signifcant challenge in the progress and development of Building-Integrated-Photovoltaic(B-I-PV)systems is concerned with the extraction of maximum power from PV *** PV system archtecture is an essential feature to extract the maximum *** conventional PV-centralinverter architecture consists of various connections among the PV modules,which are sensitive to shading effects and pro-duces mismatching power loss under partial shading conditions(PSCs),Hence,photovoltaic-distributed-maximum power point tracking(PV-D-MPPT)architecture has been proposed to extract the maximum ***-1 D-MPPT architecture,the output terminals of DC-DC converters are connected either in series or parallel *** main limitation of the series configuration in open-loop MPPT control is the crosscoupling *** of cross-coupling effects,the maximum-power-point(M-P-P)operation of shaded PV modules is lost under *** lost in M-P-P operation of shaded PV module also affects the unshaded modules M-P-P *** crosscoupling ffeets,the DC-DC converters are consuming the power instead of delivering to the *** the research activity,there are hardly any papers presenting a clear,comprehensive and mathematical analysis on the existence of cross-couplings in PV string-integrated-converters(S-1-Cs).This article presents a mathematical analysis and also explains the conditions for the existent of cross-coupling *** experimental results also validate with the mathematically analysed *** article also discusses the modeling of the two-diode model of PV module,design of boost type S-1C,and the Perturb and Observe(P&O)MPPT algorithm implementation.

关键词： Cross-coupling ffects mismatching power loss partial shading conditions(PSCs) PV-central-inverter architecture PV-D-MPPT architecture S-I-Cs series configuration

Kinetic-theory-based investigation of electronegative plasma–wall transition with two populations of electrons

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Plasma Science and Technology 2021年第3期23卷 11-21页

作者： Suresh BASNET Atit DEUJA raju KHANAL Central Department of Physics Tribhuvan UniversityKirtipurKathmandu 44613Nepal

Kinetic theory has been employed to investigate the magnetized plasma-sheath structure and its characteristics in the presence of more than one species of negatively charged particles:hot electrons,cold electrons,and negative *** cold electrons and negative ions are considered to obey a Maxwellian distribution,whereas the hot electrons follow a truncated Maxwellian *** Bohm sheath condition has been extended for the case of more than one species of negatively charged particles,in which the concentration of hot electrons has a crucial role in achieving the Bohm *** thermal motion of hot electrons is much higher compared to cold electrons and negative ions,such that the variation of hot electron concentrations and the temperature ratio of hot to cold electrons play a key role in the determination of the plasma-sheath parameters:particle densities,electrostatic potential,the flow of positive ions towards the wall,and sheath *** have estimated the deviation of the resultant drift velocity of positive ions on the plane perpendicular to the wall from the parallel component at the presheath–sheath *** is found that the deviation between the two velocity components increases with an increase in the obliqueness of the magnetic ***,the results obtained from the kinetic trajectory simulation model are compared with the results obtained using a fluid model;the results are qualitatively similar,although the potential varies by less than 4%in terms of the magnitude at the wall.

关键词： Bohm velocity fluid theory plasma sheath electronegative plasmas

Modelling die filling with charged particles using DEM/CFD

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Particuology 2012年第2期10卷 229-235页

作者： emmanuel Nkem Nwose School of Chemical Engineering University of Birmingham Birmingham B15 2TT UK

The effects of electrostatic charge on powder flow behaviour during die filling in a vacuum and in air were analysed using a coupled discrete element method and computational fluid dynamics （DEM]CFD） code, in which long range electrostatic interactions were implemented. The present 2D simulations revealed that both electrostatic charge and the presence of air can affect the powder flow hehaviour during die filling. It was found that the electrostatic charge inhibited the flow of powders into the die and induced a loose packing structure. At the same filling speed, increasing the electrostatic charge led to a decrease in the fill ratio which quantifies the volumetric occupancy of powder in the die. In addition, increasing the shoe speed caused a further decrease in the fill ratio, which was characterised using the concept of critical filling speed, When the electrostatic charge was low, the air/particle interaction was strong so that a lower critical filling speed was obtained for die filling in air than in a vacuum. With high electrostatic charge, the electrostatic interactions became dominant. Consequently, similar fill ratio and critical filling speed were obtained for die filling in air and in a vacuum.

关键词： DEMCFDElectrostaticsDie fillingPowder flowCohesionCharged particles

Scanning electron microscopy of fruits in the West African Polygonaceae

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Journal of Systematics and Evolution 2010年第5期48卷 336-343页

作者： Abiodun emmanuel AYODELE Key Laboratory of Biodiversity and Biogeography Kunming Institute of BotanyChinese Academy of Science

The fruit morphology of 18 taxa representing seven genera of the family Polygonaceae in West Africa was investigated using scanning electron *** achenes are trigonous,lenticular,globose,subglobose,heart shaped,ovoid,or cone *** range from 0.12×0.10 cm2 in Polygonum plebeium to 7.87×0.58 cm2 in Afrobrunnichia *** are brown to *** cells are isodiametric in ***,irregular in ***,Antigonon leptopus,and Harpagocarpus snowdenii,and polygonal in other *** walls are straight,curved,or undulate and are either raised or *** erecta is characterized by deeply sinuate lateral *** cell surface may be smooth or tuberculate or fibrillate in the family,usually covered with wax *** combination of these characters is mainly taxonomically useful at the tribal level and rarely at the specific or infraspecific level for the delimitation of the taxa.

关键词： fruit Polygonaceae SEM taxonomy West Africa.

Systems Analysis of Vulnerability to Hydrometeorological Threats: An Exploratory Study of Vulnerability Drivers in Northern Zimbabwe

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International Journal of Disaster Risk Science 2019年第2期10卷 204-219页

作者： emmanuel Mavhura Department of Geography Bindura University of Science Education

Disasters result from complex interactions of hazards and vulnerability conditions. Reducing human exposure and sensitivity to threats can reduce disaster impact. Prior knowledge about community vulnerability levels is crucial to minimizing potential losses from future threats. Most vulnerability studies focus on high-impact disasters and their temporal and spatial analyses. Yet highfrequency, low-impact disasters have a cumulative potential to severely disrupt or damage socioeconomic *** is limited knowledge especially in the global south about the creation of vulnerability to hydrometeorological threats. Using a systems approach, this study explores ways in which communities in the northern semiarid tropics of Zimbabwe are vulnerable to hydrometeorological *** predominantly qualitative study used literature review, interviews, transect walks, and focus groups to gather data from selected samples involving smallholder farmers with in-depth knowledge about community vulnerability. The results show that the communities are vulnerable to multiple hydrometeorological threats due to multiple interacting factors including rainfed and floodbased farming, land tenure, topography, climate, and other socioeconomic conditions such as inadequate income sources and high poverty. In order to reduce vulnerability,this study provides five policy options for government and nongovernmental organization interventions, including the need to transform rural economies beyond the traditional rainfed and flood-based farming systems.

关键词： Community vulnerability Flood-based farming Hydrometeorological threats Rainfed agriculture Zimbabwe