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Journal of Mountain Science 2018年第11期15卷 2453-2465页

作者： Anudip GOGOI uttam kumar sahoo Department of Forestry Mizoram University

Impact of anthropogenic disturbance on species diversity and vegetation structure of a lowland tropical rainforest was studied in the foothills of Eastern Himalaya, India. Tree species richness,density, basal area and the diversity indices were found significantly(P100 cm dbh class in all three sites. Density of the matured trees decreased with increasing DBH whereas, tree basal area tended to increase with increasing DBH in all three sites. Tree species richness was highest in the lower DBH classes.62.07% of the total tree species regenerated in the largely undisturbed site followed by 50% in the mildly disturbed and 26.32% in the highly disturbed *** overall regeneration condition was found to be good in the largely undisturbed site. Mildly disturbed site exhibited fair regeneration and so was in the highly disturbed site. Discernable variations in species composition, diversity, regeneration and tree population structure revealed the impact of anthropogenic disturbances on rainforest vegetation dynamics. Higher degree of disturbance was furtherly found not only affecting species diversity but also promoting the growth of invasive weed *** of Hydnocarpus kurzii and Crypteronia paniculata in the highly disturbed site also indicated that these les

关键词： Biodiversity Deforestation Abundance Vegetation Dynamics Conservation Management

Vegetation and ecosystem carbon recovery following shifting cultivation in MizoramManipur-Kachin rainforest eco-region,Southern Asia

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Ecological Processes 2020年第1期9卷 236-248页

作者： Anudip Gogoi uttam kumar sahoo Hemanta Saikia Department of Forestry Mizoram UniversityAizawl 796004India College of Sericulture Assam Agricultural UniversityJorhat 785013India

Background:Shifting cultivation(locally known as“jhum”)is a major driver of deforestation and loss of ecosystem services in *** developing any effective conservation of biodiversity and carbon service program,an indepth understanding to the recovery of vegetation and carbon after abandonment of jhum is *** estimated species richness,abundance and composition of trees,shrubs and herbs,carbon distribution in aboveground and belowground components along a chronosequence of jhum fallow in northeast India,and elucidated the factors affecting the recovery processes of jhum ***:Species composition and other plant community attributes,carbon storage in different pools were studied in 5 jhum fallows(<5,5-10,11-15,16-20,21-25 years old)and an old-growth *** data were subjected to linear mixed effect modeling using R-package“nlme”for identifying the important factors contributing to the recovery of vegetation and ***:Species composition varied significantly(P<0.05)between jhum fallows and old-growth *** density varied from 28 stems ha−1 in 5 years old jhum fallow to 163 stems ha−1 in old-growth *** biomass carbon in all components and soil organic carbon were significantly(P=0.01)lower in jhum fallows than in the old-growth forest except living non-woody biomass *** recovery of aboveground biomass carbon was faster during early successive years than the mid-successive jhum *** ecosystem carbon and soil organic carbon stock in the oldest jhum fallow was 33%and 62%of those in the old-growth forest,*** fallow age was found to be the most important explanatory factor in the recovery process of vegetation and carbon stock in re-growing ***:The shifting cultivation fallows gradually recovered both vegetation and carbon and are potential repository sites for biodiversity conservation,which may take much longer time to reach up to old-growth forest in northeast India.

关键词： Biodiversity conservation Regrowth forest Vegetation succession Carbon storage Restoration of degraded land

Study of damage behavior and repair effectiveness of patch repaired carbon fiber laminate under quasi-static indentation loading

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Defence Technology（防务技术） 2024年第4期34卷 29-41页

作者： Alok kumar Chinmaya kumar sahoo A.Arockiarajan Department of Applied Mechanics Indian Institute of Technology MadrasChennai 600036India

Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural *** work presents an experimental investigation on the effects of different patch and parent laminate stacking sequences on the enhancement of impact strength of Carbon Fiber Reinforced Polymers(CFRP)composites by utilising the adhesively bonded external patch repair *** evolution study is also performed with the aid of Acoustic Emission(AE).Two different quasi-isotropic configurations were selected for the parent laminate,viz.,[45°/45°/0°/0°]s and[45°/0°/45°/0°]*** Static Indentation(QSI)test was performed on both the pristine laminates,and damage areas were detected by using the C-scan inspection *** laminates were repaired by using a single-sided patch of two different configurations,viz.,[45°/45°/45°/45°]and[45°/0°/0°/45°],and employing a circular plug to fill the damaged *** different combinations of repaired laminates with two configurations of each parent and patch laminate were produced,which were further subjected to the QSI *** results reveal the effectiveness of the repair method,as all the repaired laminates show higher impact resistance compared to the respective pristine *** of[45°/0°/0°/45°]configuration when repaired by taking[45°/45°/0°/0°]s and[45°/0°/45°/0°]s as parents exhibited 68%and 73%higher peak loads,respectively,than the respective pristine ***,parent and patch of configuration[45°/0°/45°/0°]s and[45°/0°/0°/45°],respectively,attain the highest peak load,whereas[45°/45°/0°/0°]s and[45°/45°/45°/45°]combinations possess the most gradual decrease in the load.

关键词： Carbon fiber reinforced polymers(CFRP) Quasi-isotropic laminate Quasi static indentation(QSI) Acoustic emission(AE) Composite repair

Effect of Land Use Changes on Carbon Stock Dynamics in Major Land Use Sectors of Mizoram, Northeast India

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Journal of Environmental Protection 2018年第12期9卷 1262-1285页

作者： Soibam Lanabir Singh uttam kumar sahoo Anudip Gogoi Alice Kenye Department of Forestry School of Earth Sciences & Natural Resource Management Mizoram University Aizawl India

Land use change activities have greatly affected the total ecosystem carbon stock (TECS) and also contribute to global change through emission of greenhouse gases. The present study assessed the change in vegetation biomass carbon stock (VBCS) and soil organic carbon stock (SOCS) following conversion in major land use sectors (agriculture, agroforestry, forest and plantation) in Mizoram, Northeast India. SOCS was the highest in agroforestry (50.85 Mg C ha-1) and the lowest in agriculture (33.99 Mg C ha-1). VBCS was the highest in plantation (131.66 Mg C ha-1) and the lowest in agriculture (7.44 Mg C ha-1). The highest positive TECS change rate was observed when agriculture was converted to plantation (6.61 Mg C ha-1·yr-1), while negative rate of change in carbon stock was observed following the establishment of agriculture from other land use. A positive rate of change was observed in both VBCS and SOCS with TECS rate of 3.58 Mg C ha-1·yr-1 when agriculture got converted to agroforestry. The absolute carbon stock change rates were higher in VBCS than SOCS signifying the importance to maintain tree based vegetation cover.

关键词： Land Use Change Soil Organic Carbon Stock Vegetation Biomass Carbon Stock

Assessment of Growth, Carbon Stock and Sequestration Potential of Oil Palm Plantations in Mizoram, Northeast India

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Journal of Environmental Protection 2018年第9期9卷 912-931页

作者： Soibam Lanabir Singh uttam kumar sahoo Alice Kenye Anudip Gogoi Department of Forestry School of Earth Sciences & Natural Resource Management Mizoram University Aizawl India

A study was conducted to assess growth, carbon stock and sequestration potential of oil palm plantations along a chronosequence in Mizoram, Northeast India for which a total of 148 oil palms drawn from different age group plantations (1 to 11 years) were sampled for their biometric parameters and assessment of carbon stock through partial non-destructive methods. All the growth parameters of oil palm (trunk height, crown depth, total height, trunk diameter) and biomass drew from different parts of the palm showed a significant (p belowground biomass (BGB) > standing litter biomass > deadwood biomass > understorey biomass. AGB, BGB and deadwood biomass followed an increasing trend while understorey biomass decreased with age. An 11-year oil palm plantation accumulated 111.96 Mg ha-1 biomass with a carbon density of 49.90 Mg C ha-1 and could sequester 3.70 Mg C ha-1 year-1 in 10 years after planting in Mizoram, Northeast India. The findings showed considerable carbon storage with comparative higher values in oil palm plantations than shifting cultivation fallows. This will enable policy and decision makers in framing climate change mitigation and adaptation policies regarding the extension of oil palm plantations in Mizoram.

关键词： Oil Palm Above Ground Biomass Carbon Stock Carbon Sequestration Potential Northeast India

Forest Dwellers’ Perception on Climate Change and Their Adaptive Strategies to Withstand Impacts in Mizoram, North-East India

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Journal of Environmental Protection 2018年第13期9卷 1372-1392页

作者： uttam kumar sahoo Soibam Lanabir Singh Snehasudha S. sahoo Lal Nundanga Lal Nuntluanga Angom S. Devi John Zothansiama Department of Forestry Mizoram University Aizawl India Indian Institute of Science Education & Research Kolkata India Department of Environmental Science Mizoram University Aizawl India

We studied the perception of forest-dependent communities on climate change with its associated risk and their adaptation strategies in Mizoram, Northeast India. A total of 360 respondents (household heads) were randomly selected from 24 villages across the three different agro-climatic zones prevalent. The community perceived awareness of climate change phenomena in the region with a positive correlation between age, education and occupation of the respondents. The overall perception of climate change in temperature was medium (0.49), while low for change in precipitation (0.26) and seasonal durability (0.23). The community showed over-all low score of perception on risk of climate change (0.10) where risk on livelihood and socio-economic factors was higher than risk to environment or forest. Perception on impact of climate change was high for forest abi-otic ecological factors (0.66) and flora and fauna (0.62), while medium on livelihood of forest-dependent communities (0.44). The majority (more than 75%) of the respondents agreed that human beings are involved and responsible for climate change. Adoption of adaptive strategies to cope climate change ranged from 0.07 to 0.91, amongst which zero tillage, use of traditional knowledge, forest fire prevention, soil and water conservation techniques, agroforestry practices and social forestry are popular. However, rain water harvesting and investments for crop insurance were adopted on low scores clearly implied by the educational and socio-economic status of the farmers in the majority. The study brings out the knowledge and perceptions to climate change by forest-dependent communities and their adaptive strategies to cope had been assessed. The finding results seek the attention of researchers and policy makers to integrate technological and financial interventions in supporting farmer’s effort to cope with climate change with a long term objective for improving their livelihood and climate sensitive resources at the

关键词： Perceptions Climate Change Adaptation Forest Policy Northeast Indi

Highly Efficient Back‑End‑of‑Line Compatible Flexible Si‑Based Optical Memristive Crossbar Array for Edge Neuromorphic Physiological Signal Processing and Bionic Machine Vision

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Nano-Micro Letters 2024年第11期16卷 323-339页

作者： Dayanand kumar Hanrui Li Dhananjay D.Kumbhar Manoj kumar Rajbhar uttam kumar Das Abdul Momin Syed Georgian Melinte Nazek El‑Atab Smart Advanced Memory Devices and Applications(SAMA)LaboratoryElectrical and Computer EngineeringComputer Electrical Mathematical Science and EngineeringKing Abdullah University of Science and Technology(KAUST)23955‑6900 ThuwalSaudi Arabia

The emergence of the Internet-of-Things is anticipated to create a vast market for what are known as smart edge devices,opening numerous opportunities across countless domains,including personalized healthcare and advanced *** 3D integration,edge devices can achieve unprecedented miniaturization while simultaneously boosting processing power and minimizing energy ***,we demonstrate a back-end-of-line compatible optoelectronic synapse with a transfer learning method on health care applications,including electroencephalogram(EEG)-based seizure prediction,electromyography(EMG)-based gesture recognition,and electrocardiogram(ECG)-based arrhythmia *** experiments on three biomedical datasets,we observe the classification accuracy improvement for the pretrained model with 2.93%on EEG,4.90%on ECG,and 7.92%on EMG,*** optical programming property of the device enables an ultralow power(2.8×10^(-13) J)fine-tuning process and offers solutions for patient-specific issues in edge computing ***,the device exhibits impressive light-sensitive characteristics that enable a range of light-triggered synaptic functions,making it promising for neuromorphic vision *** display the benefits of these intricate synaptic properties,a 5×5 optoelectronic synapse array is developed,effectively simulating human visual perception and memory *** proposed flexible optoelectronic synapse holds immense potential for advancing the fields of neuromorphic physiological signal processing and artificial visual systems in wearable applications.

关键词： Neuromorphic computing Electrophysiological signal Artificial vision system Image recognition Memristor

Palaeodepositional environment,implications of Glossopteris flora,and organic matter characteristics from the Lower Permian,Karo Open Cast Mine,East Bokaro Coalfield,Damodar Basin,India

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Journal of Palaeogeography 2024年第3期13卷 528-546页

作者： Sankar Suresh kumar Pillai Rose Ann Sebastian Runcie Paul Mathews Srikanta Murthy Anju Saxena Mrutyunjaya sahoo Suraj kumar Sahu Gulshan kumar Dhingra Birbal Sahni Institute of Palaeosciences 53 University RoadLucknow-226007UPIndia Academy of Scientific and Innovative Research(AcSIR) Ghaziabad-201002India Department of Geology School of Earth Science SystemsCentral University of KeralaKasaragod-671316KeralaIndia Department of Geology Ravenshaw UniversityCuttack-753003OdishaIndia Department of Botany Sri Dev Suman Uttarakhand UniversityUttarakhand-249145India

The present study deals with the Early Permian floral diversity,palaeoenvironment,palaeoclimate and depositional setting using a multiproxy approach that includes morphotaxonomy,palynology,and organic geochemistry of Karo OCM(Open Cast Mine),East Bokaro Coalfield,Damodar Gondwana Basin,*** Permian sediments of Peninsular India are widely regarded as fluvial,along with some marine *** macroplant fossil assemblage exhibits the presence of Glossopteridales,comprising Glossopteris,Gangamopteris,and Vertebraria,as well as Coniferales,which includes *** palynological assemblage encompasses the dominance of the striate bisaccate pollen Faunipollenites *** the subdominance of the non-striate bisaccate pollen Scheuringipollenites *** glossopterid *** megafloral and palynofloral assemblage confirms the biostratigraphical age to be Late Barakar palynoflora of Kungurian *** studied morphological characteristics,including small to large Glossopteris leaves exhibiting a lanceolate shape,acute apices,and acute cuneate or tapering bases,as well as entire margins with narrower lamina and narrow meshes,suggest the existence of a dense forest with the prevalence of a warm and humid climate during their *** organic geochemical characterization based on functional group and biomarker analyses reveals the diagenetic effects on organic *** symmetric(~2865-2855 cm^(-1))and asymmetric stretching(~2930-2910 cm^(-1))peaks are identifiable in coal samples,whereas they are absent in carbonaceous *** A-factor vs.C-factor plot suggests that the kerogen type is type Ⅲ,which can generate mainly gaseous *** vitrinite reflectance studies(R_(r) av.1.1%)show increased maturity of the samples,which is supported by the n-alkane distribution pattern and the absence of hopane *** Indian floral assemblages in contemporary of southern Gondwana continents reveal a stronger inclination/affinity with th

关键词： Glossopteris Palynomorph FTIR GCMS Gondwana Permian Palaeoclimate

Improved reservoir characterization by means of supervised machine learning and model-based seismic impedance inversion in the Penobscot field,Scotian Basin

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Energy Geoscience

Energy Geoscience 2024年第2期5卷 183-201页

作者： Satya Narayan Soumyashree Debasis sahoo Soumitra Kar Sanjit kumar Pal Subhra Kangsabanik Oil and Natural Gas Corporation(ONGC)Limited DehradunIndia Department of Applied Geophysics IIT(ISM)DhanbadIndia

The present research work attempted to delineate and characterize the reservoir facies from the Dawson Canyon Formation in the Penobscot field,Scotian *** integrated study of instantaneous frequency,P-impedance,volume of clay and neutron-porosity attributes,and structural framework was done to unravel the Late Cretaceous depositional system and reservoir facies distribution patterns within the study *** strikes were found in the EW and NEE-SWW directions indicating the dominant course of tectonic activities during the Late Cretaceous period in the region.P-impedance was estimated using model-based seismic *** properties such as the neutron porosity(NPHI)and volume of clay(VCL)were estimated using the multilayer perceptron neural network with high ***,a combination of low instantaneous frequency(15-30 Hz),moderate to high impedance(7000-9500 gm/cc*m/s),low neutron porosity(27%-40%)and low volume of clay(40%-60%),suggests fair-to-good sandstone development in the Dawson Canyon *** calibration with the welllog data,it is found that further lowering in these attribute responses signifies the clean sandstone facies possibly containing *** present study suggests that the shale lithofacies dominates the Late Cretaceous deposition(Dawson Canyon Formation)in the Penobscot field,Scotian *** faults and overlying shale facies provide structural and stratigraphic seals and act as a suitable hydrocarbon entrapment mechanism in the Dawson Canyon Formation's *** present research advocates the integrated analysis of multi-attributes estimated using different methods to minimize the risk involved in hydrocarbon exploration.

关键词： Reservoir characterization Model-based inversion Multilayer perceptron(MLP) Impedance Petrophysical properties Scotian Basin

Dual-wavelength all-fiber Q-switched fiber laser using bismuth-doped fiber as saturable absorber

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Optoelectronics Letters 2024年第3期20卷 147-151页

作者： Aruna Ghosh Abdulkadir Mukhtar Diblawe uttam kumar Samanta Moh Yasin Sulaiman Wadi Harun Mukul Chandra Paul Fiber Optics and Photonics Division CSIR-Central Glass and Ceramic Research InstituteKolkata 700032India Physics Department Jadavpur UniversityKolkata 700032India Photonics Engineering Laboratory Department of Electrical EngineeringUniversity of MalayaKuala Lumpur 50603Malaysia Department of Physics Faculty of Science and TechnologyAirlangga UniversitySurabayaIndonesia

A passively Q-switched all-fiber laser is demonstrated using a 10-cm-long bismuth-doped fiber(BDF) as a saturable absorber(SA). The dual-wavelength operation was obtained due to the nonlinear effect inside the fabricated BDF, which has a high germanium content. Stable Q-switched pulses were obtained at the dual synchronous wavelengths of 1 530.1 nm and 1 531.1 nm. When the pump power is tuned from 105.3 mW to 191.0 mW, the repetition rate can be varied from 82.6 kMz to 117.6 kHz. The maximum pulse energy and average output power were 83.4 nJ and 9.8 mW, respectively while the minimum pulse width was 8.5 μs at the maximum pump power of 191.0 mW. Our results indicate that BDF could be a promising alternative optical modulator for pulsed fiber laser application.

关键词： fiber switched pump