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Reduced tillage with residue retention improves soil labile carbon pools and carbon lability and management indices in a seven-year trial with wheat-mung bean-rice rotation

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Pedosphere 2022年第6期32卷 916-927页

作者： Rafeza BEGUm mohammad m.R.JAHANGIR mohammad JAHIRUDDIN mohammad Rafiqul islam Shaikh m.BOKHtIAR Khandakar R.islam Department of Soil Science Bangladesh Agricultural UniversityMymensingh 2202(Bangladesh) Soil Resource Development Institute Dhaka 1215(Bangladesh) South Asian Association for Regional Cooperation(SAARC)Agriculture Center Dhaka 1215(Bangladesh) the Ohio State University Columbus OH 43235(USA)

Soil total organic carbon(tOC)is a composite indicator of soil quality with implications for crop production and the regulation of soil ecosystem *** reports on the dynamics of tOC as a consequence of soil management practices in subtropical climatic conditions,where microbial carbon(C)loss is high,are very *** objective of our study was to evaluate the impact of seven years of continuous tillage and residue management on soil tOC dynamics(quantitative and qualitative)with respect to lability and stratification under an annual wheat-mung bean-rice cropping *** soil samples were collected at 0-15 and 15-30 cm depths from a three-replicate split-plot experiment with tillage treatment as the main plots and crop residue levels as the *** tillage treatments included conventional tillage(Ct)and strip tillage(St).Residue levels were high residue level(HR),30%of the plant height,and low residue level(LR),15%.In addition to tOC,soil samples were analyzed for particulate organic C(POC),permanganate oxidizable C(POXC),basal respiration(BR),specific maintenance respiration rate(qCO_(2)),microbial biomass C(mBC),potentially mineralizable C(PmC),and tOC lability and management *** St treatment significantly increased the tOC and labile C pools at both depths compared with the Ct treatment,with the effect being more pronounced in the surface *** HR treatment increased tOC and labile C pools compared with the LR *** St+HR treatment showed significant increases in mBC,metabolic quotient(qR),C pool index(CPI),C lability index(CL_(I)),and C management index(CmI),indicating improved and efficient soil biological activities in such systems compared with the Ct ***,the stratification values,a measure of soil quality improvement,for POC and mBC were>2,indicating improved soil quality in the St+HR treatment compared with the Ct *** St+HR treatment not only significantly increased the contents o

关键词： basal respiration carbon management index carbon stratification particulate organic carbon permanganate oxidizable carbon total organic carbon

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Evolution of plasma parameters in an Ar-N2/He inductive plasma source with magnetic pole enhancement

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Plasma Science and technology 2017年第2期19卷 34-42页

作者： maria YOUNUS N U REHmAN m SHAFIQ m NAEEm m ZAKA-UL-islam m ZAKAULLAH Department of Physics Plasma Physics LaboratoryQuaid-i-Azam University45320 IslamabadPakistan Plasma Physics Laboratory Department of PhysicsCOMSATS Institute of Information Technology44000 IslamabadPakistan Department of Physics Faculty of ScienceJazan University114 JazanSaudi Arabia

magnetic pole enhanced inductively coupled plasmas （maPE-ICPs） are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optical emission spectroscopy were used to monitor the evolution of plasma parameters in a maPE-ICP Ar-Na/He mixture plasma. Electron density （ne） and temperature （te）, excitation temperature （texc）, plasma potential （Vp）, skin depth （6） and the evolution of the electron energy probability function （EEPF） are reported as a function of radiofrequency （RF） power, pressure and argon concentration in the mixture. It is observed that ne increases while te decreases with increase in RF power and argon concentration in the mixture. the emission intensity of the argon line at 750.4 nm is also used to monitor the variation of the ‘high-energy tail＇ of the EEPF with RF power and gas pressure. the EEPF has a ‘bi-maxwellian＇ distribution at low RF powers and higher pressure in a pure N2 discharge. However, it evolves into a ‘maxwellian＇ distribution at RF powers greater than 70 W for pure N2, and at 50 W for higher argon concentrations in the mixture. the effect of argon concentration on the temperatures of two electron groups in the ‘bi-maxwellian＇ EEPF is examined. the temperature of the low-energy electron group tL shows a decreasing trend with argon addition until the ‘thermalization＇ of the two temperatures occurs, while the temperature of high-energy electrons ta decreases continuously.

关键词： maPE-ICP Langmuir probe OES EEPF

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Nonlinear forced vibration in a subcritical regime of a porous functionally graded pipe conveying fluid with a retaining clip

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Applied mathematics and mechanics(English Edition) 2025年第1期46卷 101-122页

作者： m.GHOLAmI m.EFtEKHARI Department of mechanical Engineering Shahid Bahonar University of Kerman

this study examines the nonlinear behaviors of a clamped-clamped porous pipe made of a functionally graded material(FGm) that conveys fluids and is equipped with a retaining clip, focusing on primary resonance and subcritical dynamics. the nonlinear governing equations for the FGm pipe are derived by the extended Hamilton's principle, and subsequently discretized through the application of the Galerkin *** direct method of multi-scales is then used to solve the derived equations. A thorough analysis of various parameters, including the clip stiffness, the power-law index, the porosity, and the clip location, is conducted to gain a comprehensive understanding of the system's nonlinear dynamics. through the analysis of the first natural frequency, the study highlights the influence of the flow velocity and the clip stiffness, while the comparisons with metallic pipes emphasize the role of FGm composition. the examination of the forced response curves reveals saddle-node bifurcations and their dependence on parameters such as the detuning parameter and the power-law index, offering valuable insights into the system's nonlinear resonant behavior. Furthermore, the frequency-response curves illustrate the hardening nonlinearities influenced by factors such as the porosity and the clip stiffness, revealing nuanced effects on the system response and resonance characteristics. this comprehensive analysis enhances the understanding of nonlinear behaviors in FGm porous pipes with a retaining clip, providing key insights for practical engineering applications in system design and optimization.

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Improved prediction of shear wave velocity for clastic sedimentary rocks using hybrid model with core data

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Journal of Rock mechanics and Geotechnical Engineering 2021年第6期13卷 1466-1477页

作者： mohammad islam miah Department of Petroleum and mining Engineering Chittagong University of Engineering and TechnologyChittagong4349Bangladesh

Accurate measurement of acoustic velocities of sedimentary rocks is essential for prediction of rock elastic constants and well failure analysis during drilling *** measurement by advanced logging tools such as dipole sonic imager is not always *** older wells,such data are not available in most ***,it is an alternate way to develop a reliable correlation to estimate the shear wave velocity from existing log and/or core *** objective of this research is to investigate the nature of dependency of different reservoir parameters on the shear wave velocity(VS) of clastic sedimentary rocks,and to identify the parameter/variable which shows the highest level of *** the study,data-driven connectionist models are developed using machine learning approach of least square support vector machine(LSSVm).the coupled simulated annealing(CSA) approach is utilized to optimize the tuning and kernel parameters in the model *** performance of the simulation-based model is evaluated using statistical *** is found that the most dependency predictor variable is the compressional wave velocity,followed by the rock porosity,bulk density and shale volume in turn.A new correlation is developed to estimate VS,which captures the most influential parameters of sedimentary *** new correlation is verified and compared with existing models using measured data of sandstone,and it exhibits a minimal error and high correlation coefficient(R^(2)-0.96).the hybridized LSSVm-CSA connectionist model development strategy can be applied for further analysis to predict rock mechanical ***,the improved correlation of VS can be adopted to estimate rock elastic constants and conduct wellbore failure analysis for safe drilling and field development decisions,reducing the exploration costs.

关键词： machine learning Acoustic shear velocity Elastic constants Rock strength Geomechanics

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General Cosmological Solutions of Einstein's Equations for Spherical, Plane and Hyperbolic Symmetric Space

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Chinese Physics Letters 2000年第2期17卷 79-81页

作者： mohammed Ashraful islam Department of mathematics and RCmPS Chittagong UniversityChittagongBangladesh

the analytic cosmological solutions of Einstein's field equations for a type of static metric representing plane, spherical and hyperbolic symmetric spaces are presented and their properties are discussed separately. A general type of solution is obtained which represents the plane, spherical and hyperbolic symmetric cosmological models. Its physical properties are also discussed in details.

关键词： Einstein hyperbolic symmetric

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Prediction of turbulent Flow Structure in a Fully Developed Rib-Roughened Narrow Rectangular Channel

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Journal of thermal Science 2009年第2期18卷 126-136页

作者： md.Shafiqul islam m.Kaminaga R.Hino m.monde Atomic Energy Research Establishment Japan Atomic Energy Agency (JAEA) Department of mechanical Engineering Saga University

Fully developed turbulent water-flow structure over one-side repeated-ribs in narrow two-dimensional rectangular channels was investigated experimentally by Particle Image Velocimetry （PIV） and analytically by the standard k-ε and nonlinear k-ε turbulent models. two rib-pitch to height ratios （p/k） of 10 and 20 were investigated while the rib height was held constant at 4 mm. the rib height-to-channel equivalent diameter ratio （k/De） was 0.1. the streamwise mean velocity and turbulent kinetic energy distributions at six selected axial stations from the center rib for the two Reynolds number （Re） of 7,000 and 20,000 were obtained and compared with the predicted one. the performance ability in predicting separating and reattaching turbulent water-flow between the standard K-ε and nonlinear k-ε models had yielded no clear conclusion. A large-scale turbulent eddy was generated by the rib promoter and then propagated into the mainstream flow, which led to the deformation of the velocity profile. the turbulent kinetic energy was increased about two times higher at p/k = 20 than that at p/k =10 under the two Reynolds numbers. the effect of the p/k value and the Reynolds number （Re） on reattachment length （XR） was investigated and showed that the p/k and Re had no significant effect on the reattachment length beyond a critical value of Re = 15,000 where XR was found to be approximately 4 times of the rib height under water-flow condition.

关键词： turbulent water-flow structure repeated-ribs narrow rectangular channels two-dimensional analysis reattachment length

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Effects of loading rate and hydraulic residence time on anoxic sulfide biooxidation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第7期8卷 1149-1156页

作者： mAHmOOD Qaisar islam Ejazul Department of Environmental Engineering Zhejiang University

the optimal operation conditions in an anoxic sulfide oxidizing (ASO) bioreactor were investigated. the maximal removal rates for sulfide and nitrate were found to be 4.18 kg/(m3·d) and 1.73 kg/(m3·d), respectively. the volumetrical volumetric loading rates (LRs) observed through decreasing hydraulic retention time (HRt) at fixed substrate concentration are higher than those by increasing substrate concentration at fixed HRt. the sulfide oxidation in ASO reactor was partially producing both sulfate and sulfur; but the amount of sulfate produced was approximately one third that of sulfur. the process was able to tolerate high sulfide concentration, as the sulfide removal percentage always remained near 99% when influent concentration was up to 580 mg/L. It tolerated relatively lower nitrate concentration because the removal percentage dropped to 85% when influent con- centration was increased above 110 mg/L. the process can tolerate shorter HRt but careful operation is needed. Nitrate conversion was more sensitive to HRt than sulfide conversion since the process performance deteriorated abruptly when HRt was decreased from 3.12 h to 2.88 h. In order to avoid nitrite accumulation in the reactor, the influent sulfide and nitrate concentrations should be kept at 280 mg/L and 67.5 mg/L respectively. Present biotechnology is useful for removing sulfides from sewers and crude oil.

关键词： Anaerobic processes Anoxic nitrate removal Biodesulfurization Biotransformation Fluidized bed bioreactors Hydraulic residence time (HRt)

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Spherically Symmetric Cosmological Solutions of Einstein’s Equations

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Chinese Physics Letters 1999年第4期16卷 247-248页

作者： mohammed Ashraful islam Department of mathematics and Research Centre for Mathematical and Physical SciencesChittagong UniversityChittagongBangladesh

two sets of solution of the Einstein’s equations of general theory of relativity which is spherically-symmetric and nonstatic homogeneous isotropic universe for perfect fluid are *** first solution is the Einstein de-Sitter type containing a scale factor(√6πкGt+a)^(4/3)and an arbitrary function f(R)of radial space *** second solution is for stiff equation of state p=ρc2,which also has a scale factor[3√8πaG∫^(t)_(0)ξ(t)dt]^(2/3)and an arbitrary function h(R)of radial space coordinates.

关键词： Einstein arbitrary radial

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Foliar Application of Cytokinin modulates Gas Exchange Features,Water Relation and Biochemical Responses to Improve Growth Performance of maize under Drought Stress

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Phyton-International Journal of Experimental Botany 2022年第3期91卷 633-649页

作者： m.Rafiqul islam m.Shahinur islam Nurunnaher Akter mohammed mohi-Ud-Din mohammad Golam mostofa Department of Agronomy Bangabandhu Sheikh Mujibur Rahman Agricultural UniversityGazipur1706Bangladesh Department of Crop Botany Bangabandhu Sheikh Mujibur Rahman Agricultural UniversityGazipur1706Bangladesh Department of Biochemistry and molecular Biology Bangabandhu Sheikh Mujibur Rahman Agricultural UniversityGazipur1706Bangladesh Institute of Genomics for Crop Abiotic Stress tolerance Department of Plant and Soil ScienceTexas Tech UniversityLubbockTX 79409USA

Improvement of plant performance under drought stress is crucial to sustaining agricultural *** current study investigated the ameliorative effects of foliar-applied kinetin,an adenine-type cytokinin(CK),on growth and gas exchange parameters,water relations and biochemical attributes of maize plants under drought ***-day-old maize plants were subjected to drought by maintaining soil moisture content at 25%field capacity for 8 days followed by foliar application of kinetin at 0,75,150 and 225 mg L^(−1)(CK0,CK75,CK150 and CK225,respectively)to the plants for two-times at the 9-day *** revealed that drought stress markedly reduced stem diameter,dry weight,chlorophyll content,gas exchange parameters and water balance but increased proline,malondialdehyde and soluble sugar contents,electrolyte leakage and senescence in maize *** of exogenous CK remarkably improved maize performance by modulating growth,gas exchange-and water relation-related parameters in a dose-dependent manner under drought ***225 increased chlorophyll content(by 61.54%),relative water content(by 49.14%),net photosynthesis rate(by 39.94%)and transpiration rate(by 121.36%)and also delayed leaf senescence but decreased internal CO_(2)concentration(by 7.38%),water saturation deficit(by 40.40%)and water uptake capacity(by 42.49%)in both well-watered and droughtstressed ***,CK application considerably decreased electrolyte leakage,proline,malondialdehyde and soluble sugar levels in drought-stressed maize plants,as also supported by heatmap and cluster *** together,exogenous CK at proper concentration(225 mg L^(−1))successfully improved maize performance under drought conditions,thereby suggesting CK application as a useful approach to alleviate drought-induced adverse effects in maize plants,and perhaps in other important crop plants.

关键词： Cytokinin drought maize osmoprotection photosynthesis water-use-efficiency

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Cardiac myxomas:A narrative review

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World Journal of Cardiology 2022年第4期14卷 206-219页

作者： A K m monwarul islam Department of Cardiology National Institute of Cardiovascular DiseasesDhaka 1207Bangladesh

Cardiac myxomas are common primary neoplasms of the *** are biologically benign but“functionally malignant”because of the potential for *** arise most commonly from the left atrium,but no chambers of the heart are *** may be sporadic in the majority but also familial as a part of the Carney *** morphological forms exist:polypoid and *** myxomas often present with obstructive features,while the papillary forms are more prone to *** is still controversial;the current view centres around origin from the primitive pluripotent mesenchymal *** may be of giant proportion,be calcified or get *** presentation typically involves the triad of intracardiac obstruction,embolic events and constitutional *** examination findings may simulate those of mitral or tricuspid *** presence of tumour plop and change of the physical findings with changing position may help differentiation between the *** is the investigation of *** polypoid or papillary mobile mass within the atrial cavity remaining attached to the interatrial septum through a stalk are the tell-tale echocardiographic *** magnetic resonance and computed tomographic scanning may have incremental diagnostic *** examination reveals abundant loose myxoid stroma with scattered round,polygonal or stellate cells with dense irregular *** testing may detect mutations in the PRKAR1A gene in the familial form of cardiac myxoma,*** Carney *** excision is the mainstay of treatment with low operative mortality,excellent postoperative survival and low recurrence *** current trend favours minimal-access surgery with or without robotic *** should have appropriate preparedness to make a timely diagnosis and enthusiastic treatment to avoid potentially fatal complications.

关键词： myxoma Cardiac Neoplasm Carney Complex Echocardiography Embolism

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