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Microplastics in soil: Impacts and microbial diversity and degradation

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Pedosphere 2022年第1期32卷 49-60页

作者： Paramdeep KAUR Kashmir singh Baljinder singh Department of Biotechnology Panjab UniversityChandigarh 160014India

Microplastics(MPs) are plastic particles less than 5 mm in size that have become a major environmental pollutant due to their ubiquitous and persistent nature. Microplastic contamination of the aquatic environment has received the most attention so far, whereas the current understanding of MP prevalence and its impacts in the terrestrial environment is largely limited. The MP contamination of soil can cause bioaccumulation and toxicity in terrestrial animals and plants, which can consequently affect human health. This review is aimed towards combining the available information on the occurrence, sources, and effects of MPs on the different aspects of the terrestrial environment and to highlight the limitations in our knowledge regarding the nature and impacts of MPs in soil. The review also highlights microbial degradation of MPs as an advancing research area, with numerous microorganisms being identified as capable of efficiently degrading this persistent contaminant.

关键词： bioaccumulation biodegradation environmental pollutants microplastic contamination persistent contaminate terrestrial environment

Rayleigh-type wave propagation in incompressible visco-elastic media under initial stress

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Applied Mathematics and Mechanics(English Edition) 2018年第3期39卷 317-334页

作者： P.singh A.CHATTOPADHYAY A.K.singh Department of Applied Mathematics Indian Institute of Technology (ISM)

Propagation of Rayleigh-type surface waves in an incompressible visco-elastic material over incompressible visco-elastic semi-infinite media under the effect of initial stresses is discussed. The dispersion equation is determined to study the effect of differ- ent types of parameters such as inhomogeneity, initial stress, wave number, phase velocity, damping factor, visco-elasticity, and incompressibility on the Rayleigh-type wave prop- agation. It is found that the affecting parameters have a significant effect on the wave propagation. Cardano＇s and Ferrari＇s methods are deployed to estimate the roots of dif- ferential equations associated with layer and semi-infinite media. The MATHEMATICA software is applied to explicate the effect of these parameters graphically.

关键词： Rayleigh-type wave inhomogeneity initial stress visco-elasticity incom-pressible

Assessment of glacier stored water in Karakoram Himalaya using satellite remote sensing and field investigation

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Journal of Mountain Science 2019年第4期16卷 836-849页

作者： Kamal Kant singh Harendra singh NEGI Dhiraj Kumar singh Snow and Avalanche Study Establishment

Karakoram Himalaya(KH) has continental climatic conditions and possesses largest concentration of glaciers outside the polar regions. The melt water from these glaciers is a major contributor to the Indus river. In this study, various methods have been used to estimate the ice volume in the Karakoram Range of glaciers such as Coregistration of Optically Sensed Images and Correlation(COSI-Corr) method and Area-Volume relations. Landsat 8 satellite data has been used to generate the ice displacement, velocity and thickness map. Our study for 558 Karakoram glaciers revealed that the average ice thickness in Karakoram is 90 m. Ground Penetrating Radar(GPR) survey has been conducted in one of the KH glacier i.e. Saser La glacier and the collected GPR data is used for the validation of satellite derived thickness map. GPR measured glacier thickness values are found comparable with satellite estimated values with RMSE of 4.3 m. The total ice volume of the Karakoram glaciers is estimated to be 1607±19 km3(1473±17 Gt), which is equivalent to 1473±17 km3 of water equivalent. Present study also covers the analysis of glacier surface displacement, velocity and ice thickness values with reference to glacier mean slope.

关键词： Glacier COSI-Corr Karakoram Range Ground Penetrating Radar GPR Volume-Area

Anisotropic turbulence of kinetic Alfvén waves and heating in solar corona

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Research in Astronomy and Astrophysics 2019年第12期19卷 327-342页

作者： Hemam Dinesh singh Bheem singh Jatav Department of Physics Sikkim University

Understanding solar coronal heating has been one of the unresolved problems in solar physics in spite of the many theories that have been developed to explain it. Past observational studies suggested that kinetic Alfven waves(KAWs) may be responsible for solar coronal heating by accelerating the charged particles in solar plasma. In this paper, we investigated the transient dynamics of KAWs with modified background density due to ponderomotive force and Joule heating. A numerical simulation based on pseudospectral method was applied to study the evolution of KAW magnetic coherent structures and generation of magnetic turbulence. Using different initial conditions in simulations, the dependence of KAW dynamics on the nature of inhomogeneous solar plasma was thoroughly investigated. The saturated magnetic power spectra follow Kolmogorov scaling of k^-5/3 in the inertial range, then followed by steep anisotropic scaling in the dissipation range. The KAW has anisotropy of k||∝ k^0.53⊥, k|| ∝ k^0.50⊥, k||∝ k^0.83⊥ and k||∝ k^0.30⊥ depending on the kind of initial conditions of inhomogeneity. The power spectra of magnetic field fluctuations showing the spectral anisotropy in wavenumber space indicate that the nonlinear interactions may be redistributing the energy anisotropically among higher modes of the wavenumber. Therefore, anisotropic turbulence can be considered as one of the candidates responsible for the particle energization and heating of the solar plasmas.

关键词： plasmas turbulence waves Sun:corona

Novel microbial fuel cell design to operate with different wastewaters simultaneously

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Journal of Environmental Sciences 2016年第4期28卷 105-111页

作者： Abhilasha singh Mathuriya Department of Biotechnology Anand Engineering College

A novel single cathode chamber and multiple anode chamber microbial fuel cell design（MAC-MFC）was developed by incorporating multiple anode chambers into a single unit and its performance was *** 60 days of operation,performance of MAC-MFC was assessed and compared with standard single anode/cathode chamber microbial fuel cell（SC-MFC）.The tests showed that MAC-MFC generated stable and higher power outputs compared with SC-MFC and each anode chamber contributed ***,MAC-MFCs were incorporated with different wastewaters in different anode chambers and their behavior in MFC performance was ***-MFC efficiently treated multiple wastewaters simultaneously at low cost and small space,which claims its candidature for future possible scale-up applications.

关键词： Microbial fuel cells Multiple wastes Bioelectricity New design Wastewater treatment

Soil Carbon Dynamics Under Changing Climate A Research Transition from Absolute to Relative Roles of Inorganic Nitrogen Pools and Associated Microbial Processes:A Review

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Pedosphere 2017年第5期27卷 792-806页

作者： pratap srivastava rishikesh singh sachchidanand tripathi pardeep singh shikha singh hema singh akhilesh singh raghubanshi pradeep kumar mishra department of chemical engineering and technology indian institute of technologybanaras hindu universityVaranasi 221005(India) institute of environment&sustainable development(iesd) banaras hindu universityVaranasi 221005(India) department of botany deen dayal upadhyaya collegeuniversity of delhiNew Delhi 110015(India) department of environmental studies pannalal girdharlal dayanand anglo-vedic collegeuniversity of delhiNew Delhi 110065(India) ecosystems analysis laboratory department of botanyinstitute of sciencebanaras hindu universityVaranasi 221005(India)

It is globally accepted that soil carbon （C） dynamics are at the core of interlinked environmental problems, deteriorating soil quality and changing climate. Its management remains a complex enigma for the scientific community due to its intricate relationship with soil nitrogen （N） availability and moisture-temperature interactions. This article reviews the management aspects of soil C dynamics in light of recent advances, particularly in relation to the availability of inorganic N pools and associated microbial processes under changing climate. Globally, drastic alterations in soil C dynamics under changing land use and management practices have been primarily attributed to the variation in soil N availability, resulting in a higher decomposition rate and a considerable decline in soil organic C （SOC） levels due to increased soil CO2 emissions, degraded soil quality, and increased atmospheric CO2 concentrations, leading to climate warming. Predicted climate warming is proposed to enhance SOC decomposition, which may further increase soil N availability, leading to higher soil CO2 effiux. However, a literature survey revealed that soil may also act as a potential C sink, if we could manage soil inorganic N pools and link microbial processes properly. Studies also indicated that the relative, rather than the absolute, availability of inorganic N pools might be of key importance under changing climate, as these N pools are variably affected by moisture-temperature interactions, and they have variable impacts on SOC turnover. Therefore, multi-factorial studies are required to understand how the relative availability of inorganic N pools and associated microbial processes may determine SOC dynamics for improved soil C management.

关键词： agro-management immobilization NH4+-N to NO3-N ratio nitrification relative availability soil C02 effiux

Investigation of microstructure and mechanical properties of friction stir welded AZ61 magnesium alloy joint

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Journal of Magnesium and Alloys 2018年第3期6卷 292-298页

作者： Kulwant singh Gurbhinder singh Harmeet singh I.K.Gujral Punjab Technical University KapurthalaPunjabIndia Guru Kashi University Talwandi SaboPunjabIndia

Increasing global demands for energy conservation and environmental protection led to the replacement of heavy components with lighter *** magnesium alloys are believed to be unique candidates for lightweight applications and friction stir welding(FSW)is capable of joining magnesium alloys,in the current work,FSW joint of AZ61 Mg alloy has been *** and mechanical properties of the joints were *** elongated grains of the base metal were recrystallized in the stir zone and in transition zone during friction stir *** formation of finer grains in the stir zone of the joint is responsible for increase the hardness of the stir *** microhardness of base metal is higher than that of thermo-mechanically affected zone but lower than that of stir *** tensile strength of the weld was about 82%of the as-received base *** joint failed in ductile *** ductile failure of joint was due to the uniform deformation of material.

关键词： Magnesium alloy Friction stir welding Stir zone Microhardness Microstructure AZ61

Bianchi type V universe with bulk viscous matter and time varying gravitational and cosmological constants

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Research in Astronomy and Astrophysics 2012年第11期12卷 1457-1466页

作者： Prashant singh Baghel Jagdish Prasad singh Department of Mathematical Sciences A. P. S. University

We consider spatially homogeneous and anisotropic Bianchi type V space- time with a bulk viscous fluid source, and time varying gravitational constant G and cosmological term A. The coefficient of bulk viscosity ζ is assumed to be a simple linear function of the Hubble parameter H （i.e. ζ = ζ0 ＋ ζ1H, where ζ0 and ζ1 are constants）. The Einstein field equations are solved explicitly by using a law of varia- tion for the Hubble parameter, which yields a constant value of the deceleration pa- rameter. Physical and kinematical parameters of the models are discussed. The models are found to be compatible with the results of astronomical observations.

关键词： bulk viscosity -- Bianchi V -- relativity: equation of state -- cosmology:cosmological parameters -- miscellaneous

Spatio-temporal evaluation of Zr plasma parameters in a single-beam-splitting double-pulse laser-induced plasma

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Plasma Science and Technology 2021年第2期23卷 47-56页

作者： Arnab SARKAR Manjeet singh Fuel Chemistry Division Bhabha Atomic Research CentreMumbai 400085India Homi Bhabha National Institute AnushaktinagarMumbai 400094India

The plasma shielding effect is one of the major weaknesses of laser-induced breakdown spectroscopy(LIBS)as it causes non-linearity in signal *** LIBS is typically carried out in constant laser energy,this non-linearity causes a reduction in *** this work,we systematically examine laser-induced plasma,formed by two different excitation source modes,*** pulse(SP)-excitation and single-beam-splitting double-pulse(SBS-DP)-excitation over Zr-2.5%Nb *** two most important plasma parameters influencing the emission line intensity,plasma temperature(Te)and electron density(Ne)were studied and compared for both modes of laser *** of the results conclusively demonstrates that due to the splitting of the laser energy in the SBS-DP mode,the plasma shielding effect is significantly *** reduced plasma shielding translates to an increased laser–sample coupling under SBS-DP *** imaging of the total intensity of the laser-induced plasma in both excitation modes was also *** study shows how the plasma shielding effect can be reduced to improve the analytical quality of the LIBS methodology.

关键词： LIBS single-beam-splitting double pulse spatial-temporal evolution plasma temperature electron density