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Identification of optimal composition with superior electrochemical properties along the zero Mn^(3+)line in Na_(0.75)(Mn-Al-Ni)O_(2)pseudo ternary system
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作者 Hari Narayanan Vasavan Manish Badole +8 位作者 Samriddhi Saxena Velaga Srihari Asish Kumar Das Pratiksha Gami Neha Dagar Sonia Deswal Pradeep Kumar Himanshu Kumar Poswal Sunil Kumar 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第9期206-216,共11页
Biphasic layered oxide cathodes,known for their superior electrochemical performance,are prime candidates for commercializing in Na-ion batteries.Herein,we unveil a series of P3/P2 monophasic and biphasic Al-substitut... Biphasic layered oxide cathodes,known for their superior electrochemical performance,are prime candidates for commercializing in Na-ion batteries.Herein,we unveil a series of P3/P2 monophasic and biphasic Al-substituted Na_(3/4)Mn_(5-x/8)Al_(2x/8)Ni_(3-x/8)O_(2)layered oxide cathodes that lie along the‘zero Mn^(3+)line’in the Na_(3/4)(Mn-Al-Ni)O_(2)pseudo-ternary system.The structural analysis showed a larger Na^(+)conduction bottleneck area in both P3 and P2 structures with a higher Al3+content,which enhanced their rate performance.In each composition,the P3/P2 biphasic compound with nearly equal fractions of P3 and P2 phases outperformed their monophasic counterparts in almost all electrochemical performance parameters.Operando synchrotron XRD measurements obtained for the monophasic P3 and biphasic P2/P3 samples revealed the absence of the O3 phase during cycling.The high structure stability and faster Na^(+)transport kinetics in the biphasic samples underpins the enhancement of electrochemical properties in the Al-substituted P3/P2 cathodes.These results highlight fixed oxidation state lines as a novel tool to identify and design layered oxide cathodes for Na-ion batteries in pseudo-ternary diagrams involving Jahn-Teller active cations. 展开更多
关键词 Layered oxides Biphasic cathode Operando Synchrotron XRD Electrochemical behavior Cyclic performance
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VARIATION OF PHYSICO-CHEMICAL PROPERTIES OF RADIATION CROSSLINKED RUBBER WITH STORAGE TIME
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作者 N.C.Dafader M.E.Haque F.Akhtar 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2005年第5期497-501,共5页
The effect of storage on physico-chemical properties of non-irradiated natural rubber and radiation vulcanized natural rubber (RVNR) were evaluated. The rubber films were stored under two different conditions, namel... The effect of storage on physico-chemical properties of non-irradiated natural rubber and radiation vulcanized natural rubber (RVNR) were evaluated. The rubber films were stored under two different conditions, namely in open air and sealed polyethylene bags. The antioxidant, tris(nonylated phenyl) phosphite (TNPP) was used for preventing degradation of RVNR films. Gel content, cross-link density, tensile strength at break and 500% elongation of rubber films were measured. The results show that the retention (%) of tensile properties of rubber films with TNPP is higher than that of rubber films without antioxidants. The rubber films stored in polyethylene bags also show better retention of tensile properties than those of rubber films stored in open air. 展开更多
关键词 Storage RADIATION Tensile Properties Antioxidant.
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STUDY ON THE PROPERTIES OF BLEND OF NATURAL RUBBER LATEX/METHYL METHACRYLATE GRAFTED RUBBER LATEX BY GAMMA RADIATION
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作者 N.C. Dafader M.E. Haque F. Akhtar 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2007年第5期519-523,共5页
Natural rubber latex (NRL) and methyl methacrylate (MMA) grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The tens... Natural rubber latex (NRL) and methyl methacrylate (MMA) grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The tensile properties, swelling ratio and permanent set were measured. The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy. Modulus increases from 6.99 MPa to 9.87 MPa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose. Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends. The decreasing trend of permanent set is high up to 5 kGy absorbed dose, and beyond that dose, it becomes almost flat. 展开更多
关键词 Natural rubber latex MMA grafted rubber latex Blend rubber Irradiation Cross-link.
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Thermoluminescence characteristics of NaSr_4(BO_3)_3:Ce^(3+) under β-ray irradiation
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作者 姜丽宏 张彦立 +5 位作者 李成宇 庞然 师丽丽 张粟 郝景权 苏锵 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第2期320-322,共3页
The thermoluminescence (TL) properties of Ce3+ doped NaSr4(BO3)3 phosphor under the β-ray irradiation were reported. The polycrystalline sample was synthesized by high temperature solid-state reaction. The TL gl... The thermoluminescence (TL) properties of Ce3+ doped NaSr4(BO3)3 phosphor under the β-ray irradiation were reported. The polycrystalline sample was synthesized by high temperature solid-state reaction. The TL glow curve of NaSr4(BO3)3:Ce3+ phosphor was composed of only one peak. TL kinetic parameters of NaSr4(BO3)3:Ce3+ were deduced by the peak shape method, the activation energy (E) was 0.590 eV and the frequency factor was 1.008×10^6S^-1. TL dose response was linear in the range of measurement. The 3-dimensional (3D) TL emission spectrum was also recorded, the emission spectrum consisted of two bands located at 441 and 479 nm respectively, corresponding to the characteristic 4f^05d^1→2F(5/2,7/2) transitions of the Ce3+ ion. The fading behavior of the NaSr4(BO3)3:Ce3+ phosphor over a period of 15 d was also studied. 展开更多
关键词 THERMOLUMINESCENCE DOSIMETRY NaSr4(BO3)3 Β-RAY rare earths
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Small Angle X-ray Scattering Study of Precipitation Kinetics in Al-Zn-Mg-Cu Alloys 被引量:3
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作者 Zhiwei DU Tietao ZHOU +3 位作者 Peiying LIU Huanxi LI Baozhong DONG Changqi CHEN 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第4期479-483,共5页
The evolution of microstructure parameters (precipitate size and volume fraction) for two types of Al-Zn-Mg-Cu alloys (7075 and 7055) during aging has been studied by synchrotron-radiation small angle X-ray scatte... The evolution of microstructure parameters (precipitate size and volume fraction) for two types of Al-Zn-Mg-Cu alloys (7075 and 7055) during aging has been studied by synchrotron-radiation small angle X-ray scattering (SAXS).The results show that the precipitates are only a few nanorneters for both alloys ageing even at higher temperature of 160℃ for 72 h (4.44 and 5.82 nm, respectively). The maximum of the precipitate volume fraction increases with in creasing Zn content and is about 0.023-0.028 and 0.052-0.054, respectively. The coarsening of precipitate is consistent with LSW (Lifshitz-Slyozov-Wagner) model even at the initial stage where volume fraction is still varying.The activation energy of coarsening regime has been determined to be about 1.22±0.02 eV and 1.25±0.02 eV for alloys 7075 and 7055, respectively. 展开更多
关键词 Small angle X-ray scattering (SAXS) AI-Zn-Mg-Cu alloys Ageing Precipitate size Volume fraction
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Preparation and Characterization of Boron Thin Film on Iron Substrate
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作者 Ishrat REHANA D.Muhammad +1 位作者 S.Ahmed J.I.Akhter 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2007年第4期481-486,共6页
The adherent thermal layering was undertaken by chemical vapor deposition (CVD) method using saturated solution of boric acid in ultra pure CH3OH. The influence of temperature was studied by varying temperature from... The adherent thermal layering was undertaken by chemical vapor deposition (CVD) method using saturated solution of boric acid in ultra pure CH3OH. The influence of temperature was studied by varying temperature from 100 to 600℃ during the process of boron deposition. The most optimum temperature was found to be 200℃. The effect of time span was observed from 6 to 120 h. The generation of micro or nano-scale thickness could be achieved by reducing time span of the experiment. The behavior of CVD was characterized by using scanning electron microscope, absorbance spectrohotometer and atomic emission spectrograph. 展开更多
关键词 BORON Chemical vapor deposition (CVD) Scanning electron microscopy (SEM) Atomic emission spectrograph (AES) Absorbance spectrophotometer Thin film
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Scanning transmission proton microscopy tomography of reconstruction cells from simulated data
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作者 ZHANG Conghua LI Min HOU Qing 《Nuclear Science and Techniques》 SCIE CAS CSCD 2011年第2期89-94,共6页
For scanning transmission proton microscopy tomography,to compare cell images of the proton stopping power and relative electron density,two cell phantoms are designed and simulated by code FLUKA.The cell images are r... For scanning transmission proton microscopy tomography,to compare cell images of the proton stopping power and relative electron density,two cell phantoms are designed and simulated by code FLUKA.The cell images are reconstructed by the filtered back projection algorithm,and compared with their tomography imaging.The images of stopping power and relative electron density slightly vary with proton energies,but the internal images are of clear with high resolution.The organic glass image of relative electron density reveals the resolution power of proton tomography.Also,the simulation results reflect effects of the boundary enhancement,the weak artifacts,and the internal structure border extension by multiple scattering.So using proton tomography to analyze internal structure of a cell is a superior. 展开更多
关键词 细胞图像 断层扫描 显微成像 质子 模拟 数据传输 滤波反投影算法 电子密度
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Small angle X-ray scattering used in precipitation in AlZnMgCuLi alloy
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作者 杜志伟 周铁涛 +5 位作者 刘培英 陈昌麒 钟皓 洪新国 赵辉 董宝中 《中国有色金属学会会刊:英文版》 CSCD 2003年第6期1301-1305,共5页
Small angle X-ray scattering has been used to study the variation of microstructure parameters in an Al-Zn-Mg-Cu-Li alloy aged at various temperatures for various durations. Coarsening of precipitates was studied by a... Small angle X-ray scattering has been used to study the variation of microstructure parameters in an Al-Zn-Mg-Cu-Li alloy aged at various temperatures for various durations. Coarsening of precipitates was studied by analyzing the curve of kinetics strength vs the cube of radius. The results show that the coarsening of precipitates conforms to LSW principle. In addition, the characteristic of s^3J(s) vs s curves was analyzed. The results show that the curves for samples aged at 160 ℃ for various durations(24, 48 and 96 h) have negative deviation, which maybe results in the formation of certain new precipitate. In the other aging treatment states, the curves conform to Porod principle which means there is sharp boundary between the precipitates and matrix. 展开更多
关键词 AIZnMgCuLi合金 铝合金 析出 XRD 显微结构
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Isotope hydrogeochemical models for assessing the hydrological processes in a part of the largest continental flood basalts province of India
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作者 Md.Arzoo Ansari Jacob Noble +1 位作者 Archana Deodhar U.Saravana Kumar 《Geoscience Frontiers》 SCIE CAS CSCD 2022年第2期200-213,共14页
Continental Flood Basalts(CFB)occupy one fourth of the world’s land area.Hence,it is important to discern the hydrological processes in this complex hydrogeological setup for the sustainable water resources developme... Continental Flood Basalts(CFB)occupy one fourth of the world’s land area.Hence,it is important to discern the hydrological processes in this complex hydrogeological setup for the sustainable water resources development.A model assisted isotope,geochemical,geospatial and geophysical study was conducted to understand the monsoonal characteristics,recharge processes,renewability and geochemical evolution in one of the largest continental flood basalt provinces of India.HYSPLIT modelling and stable isotopes were used to assess the monsoonal characteristics.Rayleigh distillation model were used to understand the climatic conditions at the time of groundwater recharge.Lumped parameter models(LPM)were employed to quantify the mean transit time(MTT)of groundwater.Statistical and geochemical models were adopted to understand the geochemical evolution along the groundwater flow path.A geophysical model was used to understand the geometry of the aquifer.The back trajectory analysis confirms the isotopic finding that precipitation in this region is caused by orographic uplifting of air masses originating from the Arabian Sea.Stable isotopic data of groundwater showed its meteoric origin and two recharge processes were discerned;(i)quick and direct recharge by precipitation through fractured and weathered basalt,(ii)low infiltration through the clayey black cotton soil and subjected to evaporation prior to the recharge.Tritium data showed that the groundwater is a renewable source and have shorter transit times(from present day to<30 years).The hydrogeochemical study indicated multiple sources/processes such as:the minerals dissolution,silicate weathering,ion exchange,anthropogenic influences etc.control the chemistry of the groundwater.Based on the geo-electrical resistivity survey,the potential zones(weathered and fractured)were delineated for the groundwater development.Thus,the study highlights the usefulness of model assisted isotopic hydrogeochemical techniques for understanding the recharge and geochemical processes in a basaltic aquifer system. 展开更多
关键词 Stable isotopes Groundwater recharge Hydrological processes Modelling Deccan Traps
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High-pressure investigations on Piplia Kalan eucrite meteorite using in-situ X-ray diffraction and ^(57)Fe Mssbauer spectroscopic technique up to 16 GPa
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作者 Usha Chandra K.K. Pandey +1 位作者 G. Parthasarathy Surinder M. Sharma 《Geoscience Frontiers》 SCIE CAS CSCD 2016年第2期265-271,共7页
We report here high-pressure investigations on Piplia Kalan eucrite-a member of HED (Howardite -Eucrite-Diogenite) family from asteroid 4-Vesta based on synchrotron X-ray diffraction (up to 16 GPa) and ^57Fe Mossb... We report here high-pressure investigations on Piplia Kalan eucrite-a member of HED (Howardite -Eucrite-Diogenite) family from asteroid 4-Vesta based on synchrotron X-ray diffraction (up to 16 GPa) and ^57Fe Mossbauer spectroscopy (up to 8 GPa). Dominant with anorthite-rich plagioclase, pigeonite-rich pyroxene and clino-ferrosilite, the sample displayed various phase transitions attaining amorphous character at 16 GPa. These phase transitions of individual components could be explained simultaneously through variations in high-pressure XRD patterns and the Mossbauer parameters. Most prominent P21/c to C2/c transition of pigeonite and ferrosilite was exhibited both as sudden variation in Mossbauer parameters and population inversion of Fe^2+ in M1 and M2 sites between 2.9 and 3.8 GPa and variation in intensity profile in XRD patterns at 3.56 GPa. Anorthite seemed to respond more to such impact than other components in the sample. Complete amorphization in anorthite which occurred at lower pressure of - 12 GPa implied residual stress experienced due to shock impact. The presence of high pressure (monoclinic) phase of pigeonite and ferrosilite at ambient condition in this eucrite sample confirmed earlier suggestions of an early shock event. This report is an attempt to emphasize the role of anorthite in the determination of the residual stress due to impact process in the parent body thus to understand the behavioral differences amongst HED members. 展开更多
关键词 METEORITES High pressure X-ray diffraction Mossbauer spectroscopy Eucrites synchrotron radiation Ferrosilite
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MAGNETIC STRUCTURE OF DyFe_(3)
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作者 JIN Long-huan W.J.James +1 位作者 J.Rhyne R.Lemaire 《Chinese Physics Letters》 SCIE CAS 1985年第6期253-256,共4页
Powder neutron diffraction measurements have been carried out on the intermetallic compound DyFe_(3) at 4 and 295K.The magnetic structure of the compound at 4 and 295K are noncollinear but coplanar in the a-c plane,an... Powder neutron diffraction measurements have been carried out on the intermetallic compound DyFe_(3) at 4 and 295K.The magnetic structure of the compound at 4 and 295K are noncollinear but coplanar in the a-c plane,and the moments of the Dy and Fe ions lie closer to the basal plane. 展开更多
关键词 COMPOUND plane. CLOSER
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Denoising Projection Data with a Robust Adaptive Bilateral Filter in Low-Count SPECT
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作者 Susumu Nakabayashi Takashi Chikamatsu +7 位作者 Takao Okamoto Tatsuro Kaminaga Norikazu Arai Shinobu Kumagai Kenshiro Shiraishi Takahide Okamoto Takenori Kobayashi Jun’ichi Kotoku 《International Journal of Medical Physics, Clinical Engineering and Radiation Oncology》 2018年第3期363-375,共13页
Low-count SPECT images are well known to be smoothed strongly by a Butterworth filter for statistical noise reduction. Reconstructed images have a low signal-to-noise ratio (SNR) and spatial resolution because of the ... Low-count SPECT images are well known to be smoothed strongly by a Butterworth filter for statistical noise reduction. Reconstructed images have a low signal-to-noise ratio (SNR) and spatial resolution because of the removal of high-frequency signal components. Using the developed robust adaptive bilateral filter (RABF), which was designed as a pre-stage filter of the Butterworth filter, this study was conducted to improve SNR without degrading the spatial resolution for low-count SPECT imaging. The filter can remove noise while preserving spatial resolution. To evaluate the proposed method, we extracted SNR and spatial resolution in a phantom study. We also conducted paired comparison for visual image quality evaluation in a clinical study. Results show that SNR was increased 1.4 times without degrading the spatial resolution. Visual image quality was improved significantly (p < 0.01) for clinical low-count data. Moreover, the accumulation structure became sharper. A structure embedded in noise emerged. Our method, which denoises without degrading the spatial resolution for low-count SPECT images, is expected to increase the effectiveness of diagnosis for low-dose scanning and short acquisition time scanning. 展开更多
关键词 BILATERAL Filter DENOISING SPECT Nuclear MEDICINE
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Helical tomotherapy for duodenal adenocarcinoma in an elderly patient: A case report
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作者 Valentina Lancellotta Giuseppe Russo +5 位作者 Marco Lupattelli Martina Iacco Elisabetta Perrucci Claudio Zucchetti Lorenzo Falcinelli Cynthia Aristei 《World Journal of Gastrointestinal Oncology》 SCIE CAS 2017年第2期94-97,共4页
To evaluate the efficacy and feasibility of external beam radiotherapy(EBRT) for duodenal adenocarcinoma in an 84-year-old female who underwent EBRT(2.2 Gy/d for a total dose of 46.2 Gy) using helical tomotherapy(HT).... To evaluate the efficacy and feasibility of external beam radiotherapy(EBRT) for duodenal adenocarcinoma in an 84-year-old female who underwent EBRT(2.2 Gy/d for a total dose of 46.2 Gy) using helical tomotherapy(HT). Toxicity was evaluated on the National Cancer Institute's common toxicity criteria(CTCAE 3.0). The patient completed the treatment without G3-G4 toxicity. After 22-mo follow-up, she is alive and well, in complete remission with no late side effects. HT seems to be feasible and effective for duodenal adenocarcinoma in old to very old patients. 展开更多
关键词 The elderly Duodenal carcinoma Helical tomotherapy TOXICITY
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Structural and photoluminescence studies on europium-doped lithium tetraborate(Eu:Li2B4O7)single crystal grown by microtube Czochralski(μT-Cz)technique
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作者 A Kumaresh R Arun Kumar +4 位作者 N Ravikumar U Madhusoodanan B S Panigrahi K Marimuthu M Anuradha 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第5期429-433,共5页
Rare earth europium(Eu(3+))-doped lithium tetraborate(Eu:Li_2B_4O_7) crystal is grown from its stoichiometric melt by microtube Czochralski pulling technique(μT-Cz) for the first time. The grown crystals ar... Rare earth europium(Eu(3+))-doped lithium tetraborate(Eu:Li_2B_4O_7) crystal is grown from its stoichiometric melt by microtube Czochralski pulling technique(μT-Cz) for the first time. The grown crystals are subjected to powder x-ray diffraction(PXRD) analysis which reveals the tetragonal crystal structure of the crystals. UV–vis–NIR spectral analysis is carried out to study the optical characteristics of the grown crystals. The crystal is transparent in the entire visible region, and the lower cutoff is observed to be at 304 nm. The existence of BO_3 and BO_4 bonding structure and the molecular associations are analyzed by Fourier transform infrared(FTIR) spectroscopy. The results of excitation and emission-photoluminescence spectra of europium ion incorporated in lithium tetraborate(LTB) single crystal reveal that the observations of peaks at 258,297, and 318 nm in the excitation spectra and peaks at 579, 591, 597, 613, and 651 nm are observed in the emission spectra.The chromaticity coordinates are calculated from the emission spectra, and the emission intensity of the grown crystal is characterized through a CIE 1931(Commission International d'Eclairage) color chromaticity diagram. 展开更多
关键词 crystal growth optical material growth from melt photoluminescence study
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Production and Properties of Short Jute and Short E-Glass Fiber Reinforced Polypropylene-Based Composites
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作者 Md Nuruzzaman Khan Juganta K. Roy +3 位作者 Nousin Akter Haydar U. Zaman Tuhidul Islam Ruhul A. Khan 《Open Journal of Composite Materials》 2012年第2期40-47,共8页
Short jute fiber (2 - 3 mm) reinforced polypropylene PP-based composites (20% fiber by weight) were fabricated using compression molding and the mechanical properties were evaluated. Tensile strength (TS), tensile mod... Short jute fiber (2 - 3 mm) reinforced polypropylene PP-based composites (20% fiber by weight) were fabricated using compression molding and the mechanical properties were evaluated. Tensile strength (TS), tensile modulus (TM), elongation at break (Eb%), flexural strength (FS), flexural modulus (FM), impact strength (IS), and hardness of the composites were found to be 32 MPa, 850 MPa, 12%, 38 MPa, 1685 MPa, 18 kJ/m2 and 96 shore-A, respectively. Then short E-glass fiber (2 - 3 mm) reinforced PP-based composites (20% fiber by weight) were fabricated and mechanical properties were compared with short jute-based composites. Short jute-based composites showed excellent mechanical properties and comparable to short E-glass-based composites. Soil degradation test of both types of composites indi-cated that jute/PP composites significantly lost much of its mechanical properties but E-glass/PP composites retained major portion of its original integrity. Interfaces of the degraded composites were investigated by scanning electron microscopy and supported the biodegradation properties of jute/PP composites. 展开更多
关键词 JUTE FIBER E-GLASS FIBER COMPOSITES Compression MOLDING Polypropylene
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Biodegradable Colour Polymeric Film (Starch-Chitosan) Development: Characterization for Packaging Materials
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作者 M. Z. I. Mollah N. Akter +2 位作者 F. B. Quader S. Sultana R. A. Khan 《Open Journal of Organic Polymer Materials》 CAS 2016年第1期11-24,共14页
Biodegradable starch-based chitosan reinforced composite polymeric films were prepared by casting. The chitosan content in the films was varied from 20% to 80% (w/w). Tensile strength (TS) was improved significantly w... Biodegradable starch-based chitosan reinforced composite polymeric films were prepared by casting. The chitosan content in the films was varied from 20% to 80% (w/w). Tensile strength (TS) was improved significantly with the addition of chitosan but elongation at break (EB %) of the composites decreased. Tensile strength of the composites raised more with the addition of the acacia catechu content in the films varied from 0.05% to 0.2% (w/w). The better thermal stability of this prepared film was confirmed by thermo-gravimetric analysis. Structural characterization was done by Fourier transform infrared spectroscopy. Surface morphologies of the composites were examined by scanning electron microscope (SEM) which suggested sufficient homogenization of starch, chitosan and acacia catechu. Water uptake was found lower for final composites in comparison to starch/chitosan and chitosan films. The satisfactory rate of degradation in the soil is expected that the final composite film is within less than 6 months. The developed films intended to use as the alternative of synthetic non-biodegradable colored packaging films. 展开更多
关键词 CHITOSAN STARCH Acacia Catechu Composite BIODEGRADABLE Packaging
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Recharge and vulnerability assessment of groundwater resources in North west India:Insights from isotope-geospatial modelling approach
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作者 Annadasankar Roy Sitangshu Chatterjee +5 位作者 Uday Kumar Sinha Anil Kumar Jain Hemant Mohokar Ajay Jaryal Tirumalesh Keesari Harish Jagat Pant 《Geoscience Frontiers》 SCIE CAS CSCD 2024年第1期247-262,共16页
Recent studies indicate dwindling groundwater quantity and quality of the largest regional aquifer system in North West India,raising concern over freshwater availability to about 182 million population residing in th... Recent studies indicate dwindling groundwater quantity and quality of the largest regional aquifer system in North West India,raising concern over freshwater availability to about 182 million population residing in this region.Widespread agricultural activities have resulted severe groundwater pollution in this area,demanding a systematic vulnerability assessment for proactive measures.Conventional vulnerability assessment models encounter drawbacks due to subjectivity,complexity,data-prerequisites,and spatial-temporal constraints.This study incorporates isotopic information into a weighted-overlay framework to overcome the above-mentioned limitations and proposes a novel vulnerability assessment model.The isotope methodology provides crucial insights on groundwater recharge mechanisms(18O and 2H)and dynamics(3H)-often ignored in vulnerability assessment.Isotopic characterisation of precipitation helped in establishing Local Meteoric Water Line(LMWL)as well as inferring contrasting recharge mechanisms operating in different aquifers.Shallow aquifer(depth<60 m)showed significant evaporative signature with evaporation loss accounting up to 18.04%based on Rayleigh distillation equations.Inter-aquifer connections were apparent from Kernel Density Estimate(KDE)and isotope correlations.A weighted overlay isotope-geospatial model was developed combining 18O,3H,aquifer permeability,and water level data.The central and northern parts of study area fall under least(0.29%)and extremely(1.79%)vulnerable zones respectively,while majority of the study area fall under moderate(42.71%)and highly vulnerable zones(55.20%).Model validation was performed using groundwater NO3-concentration,which showed an overall accuracy up to 82%.Monte Carlo Simulation(MCS)was performed for sensitivity analysis and permeability was found to be the most sensitive input parameter,followed by 3H,18O,and water level.Comparing the vulnerability map with Land Use Land Cover(LULC)and population density maps helped in precisely identifying the high-risk sites,warranting a prompt attention.The model developed in this study integrates isotopic information with vulnerability assessment and resulted in model output with good accuracy,scientific basis,and widespread relevance,which highlights its crucial role in formulating proactive water resource management plans,especially in less explored data-scarce locations. 展开更多
关键词 Agricultural pollution Data scarcity Recharge mechanism Rayleigh distillation Isotope-geospatial model Vulnerability assessment
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Refining aquifer heterogeneity and understanding groundwater recharge sources in an intensively exploited agrarian dominated region of the Ganga Plain
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作者 Abhinav Patel Shive Prakash Rai +7 位作者 Nijesh Puthiyottil Abhinesh Kumar Singh Jacob Noble Rajesh Singh Dharmappa Hagare U.D.Saravana Kumar Nachiketa Rai Kossitse Venyo Akpataku 《Geoscience Frontiers》 SCIE CAS CSCD 2024年第4期134-147,共14页
Densely populated region of Ganga Plain is facing aquifer vulnerability through waterborne pollutants and groundwater stress due to indiscriminate abstraction,causing environmental and socio-economic instabilities.To ... Densely populated region of Ganga Plain is facing aquifer vulnerability through waterborne pollutants and groundwater stress due to indiscriminate abstraction,causing environmental and socio-economic instabilities.To address long-term groundwater resilience,it is crucial to understand aquifer heterogeneity and connectivity,groundwater recharge sources,effects of groundwater abstraction etc.In this con-text,present study aims to understand factors responsible for vertical and spatial variability of groundwater chemistry and to identify groundwater recharge sources in an intensively exploited agrarian region of the Ganga Plain.Interpretation of chemometric,statistical,and isotopic analysis categorises the alluvial aquifer into zone 1(G1;ground surface to 100 m)and zone 2(G2;>100 m-210 m).The group G1 samples are characterized by a wide variation in hydrochemical species,noted with pockets of F-and NO3-rich groundwater,and fresh to more evolved water types,while group G2 groundwater is characterized by a sharp increase in freshwater types and limited variation in their isotopic and hydrochemical species.The G1 groundwater chemistry is governed by soil mineralogy,local anthropogenic inputs(SO42-,Cl-,and NO3-),and manifested by multiple recharge sources(local precipitation,river,canal water,pond).The G2 group is dominated by geogenic processes and mainly recharged by the local precipitation.Geospatial signatures confirm more evolved water type for group G1 in northwestern region,while fresh-water type covers the rest of the study area.Fluoride rich groundwater is attributed to sodic water under alkaline conditions and enrichedδ18O values emphasizing role of evaporation in F-mobilization from micas and amphiboles abundant in the soil.The findings provide insight into potential groundwater vulnerability towards inorganic contaminants,and ground water recharge sources.The outcome of this study will help to develop aquifer resilience towards indiscriminate groundwater extraction for agricultural practices and aim towards sustainable management strategies in a similar hydrogeological setting. 展开更多
关键词 Stable isotopes Hydrogeochemical attributes Groundwater recharge sources Ganga Plain
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Hydrochemical evolution of groundwater in northwestern part of the Indo-Gangetic Basin,India:A geochemical and isotopic approach
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作者 Shive Prakash Rai Kossitse Venyo Akpataku +2 位作者 Jacob Noble Abhinav Patel Suneel Kumar Joshi 《Geoscience Frontiers》 SCIE CAS CSCD 2023年第6期450-463,共14页
The present study aims to understand the hydrochemical evolution of groundwater in the Ghaggar River Basin,representing a zone of excessive abstraction of groundwater in the northwestern Indo-Gangetic Basin.The study ... The present study aims to understand the hydrochemical evolution of groundwater in the Ghaggar River Basin,representing a zone of excessive abstraction of groundwater in the northwestern Indo-Gangetic Basin.The study comprises a regional scale and high-resolution sampling of groundwater during preand post-monsoon seasons of 2013 and their analyses for major ions,δ^(18)O,δ^(2)H,and 3 H.Variation in hydrochemical and isotopic data is found both in spatial and vertical scales.The significant vertical variation of TDS,NO_(3)and K^(+)allowed the classification of the aquifer system into two major groups:shallow(depth<80 m bgl)and deep(depth>80 m bgl).The depthwise variations ofδ^(18)O andδ^(2)H support this categorization of the aquifers.The Ca-HCO_(3)and Ca-Mg-Na-HCO_(3)water facies with higher values of 3 H in the proximal part of the basin characterize recharge areas under humid conditions.The dominance of Mg-Na-HCO_(3)and Na-HCO_(3)facies in shallow and deep aquifers in central part of the basin,illustrate the intermediate to advanced stages of hydrochemical evolution in the system.Dominance of brackish Ca-Mg-Cl-SO_(4)and Na-Cl-SO_(4)water types in the discharge areas is due to the prevailing geological conditions and anthropogenic activities.Geochemical modelling supports the reverse cation exchange and mixing during lateral and vertical flows,weathering of silicate minerals,dissolution of crustal salts,and evaporative enrichment are the natural processes governing the evolution of groundwater chemistry along the flowpaths.The developed process-based conceptual model will aid in the formulation of a suitable plan for groundwater resource management in the region. 展开更多
关键词 Hydrogeochemical evolution Groundwater salinity Cation exchange FLUORIDE Anthropogenic impact Ghaggar River Basin
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