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Electrical conductivity of Gd doped BiFeO3-PbZrO3 composite

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Frontiers of Materials Science 2013年第3期7卷 295-301页

作者： Santosh kumar SATPATHY Nilaya kumar MOHANTY ajay kumar behera Banarji behera Pratibindhya NAYAK Materials Research Laboratory School of Physics Sambalpur University Jyoti Vihar Burla-768019 Odisha India

The composite, 0.5（BiGd0.15Fe0.85O3）-0.5（PbZrO3）, was synthesized using the solid-state reaction technique. The formation of the compound was confirmed by XRD with an orthorhombic structure at room temperature. The impedance parameters were studied using an impedance analyzer in a wide range of frequency （10z-106Hz） at different temperatures. The Nyquist plot suggests the contribution of bulk effect and a slight indication of grain boundary effect and the bulk resistance decreases with a rise in temperature. The presence of temperature-dependent relaxation process occurs in the material. Electrical modulus reveals the presence of the hopping mechanism in the materials. The value of exponent n, pre-factor A and adc were obtained by fitting ac conductivity data with Jonscher＇s universal power law. The activation energies calculated from the ac conductivity were found to be 0.50, 0.46, 0.44, 0.43, 0.42 and 0.38 eV at 1, 10, 50, 100, 500 kHz and I MHz respectively in the temperature region of 110℃-350℃. The dc conductivity was found to increase with the rise in temperature. The activation energy calculated from complex impedance plot and from the fitted Jonscher＇s power law are very close, which results similar type of charge carrier exist in conduction mechanism of the material.

关键词： solid state reaction XRD impedance electrical conductivity

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

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Acta Metallurgica Sinica(English Letters) 2015年第7期28卷 847-857页

作者： ajay kumar behera N.K.Mohanty S.K.Satpathy Banarji behera P.Nayak Materials Research Laboratory School of PhysicsSambalpur University

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5（Bi LaxFe1-xO3）–0.5（Pb Ti O3）（x = 0.05,0.10,0.15,0.20）（BLxF1-x-PT） were prepared by mixed oxide *** characterization was performed by X-ray diffraction and shows a tetragonal structure at room *** lattice parameter c/a ratio decreases with increasing of La（x = 0.05–0.20） concentration of the *** effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range（102–106Hz） at different *** nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the *** electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the *** ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures（200–300 ℃）.

关键词： X-ray diffraction Composite materials Impedance spectroscopy Modulus studies Activation energy Relaxation phenomena

Geochemistry and mineral chemistry of the armoor granitoids,eastern dharwar craton: implications for the redox conditions and tectono-magmatic environment

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Acta Geochimica 2024年第1期43卷 110-133页

作者： A.ajay kumar Ch.Ashok Department of Geology Osmania UniversityHyderabad 500007India CSIR-National Geophysical Research Institute UppalHyderabad 500007India

The mineralogical and geochemical characteristics of the K-rich granites from the Armoor granitic rocks in the northeastern portion of the Eastern Dharwar Craton(EDC) are *** order to understand its physicochemical conditions,the petrogenesis of the granitoid was explained from biotite chemistry and geochemical *** of mineral chemistry expose that compositionally,K-feldspar and plagioclase in Armoor granite rocks range from An0,Ab_(3-5.9),Or_(94-96.9) and An_(5-29,-Ab71.9-94.9),Or_(0-1.5),*** mineral chemistry of biotite crystals exhibits composition that varies from primary to re-equilibrated primary *** biotites from the Armoor granites generally exhibit an I-type trend,with calc-alkaline parental magma in a subduction *** chemistry of granites displays magnetite(oxidized)series nature,which has oxygen fugacity(fO_(2))=-15.1 to-16.7(log_(10) bar),under high oxidizing *** and pressure estimates for the crystallization of Armoor granites based on biotite composition are T=612-716 ℃ and 1.0-0.4 kbar,***,these rocks are metaluminous to slightly peraluminous and magnesian,with calc-alkaline potassiumrich *** the chondrite normalized REE diagram,the granites have positive europium anomalies;rich Sr/Y,(Dy/Yb)_(N) ratios and reduced Mg#,Rb/Sr,Rb,Sr indicate that the melting of earlier rocks,crystal accumulation and residual garnet source formed at high *** examined granites show that they are produced from the melting of crustal ***,the extensive analyses of the described Armoor granite suggest that they were produced by crust sources and developed under oxidizing conditions in subduction setting.

关键词： Armoor granites Oxygen fugacity Crystal accumulation Remelting Subduction

Hopf bifurcation in a delayed prey-predator model with prey refuge involving fear effect

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International Journal of Biomathematics 2024年第5期17卷 1-32页

作者： Ankit Parwaliya Anuraj Singh ajay kumar Department of Applied Sciences ABV-Indian Institute of Information Technology and ManagementGwalior 474015India

This work investigates a prey-predator model featuring a Holling-type II functional response,in which the fear effect of predation on the prey species,as well as prey refuge,are ***,the model assumes that the growth rate of the prey population decreases as a result of the fear of ***,the detection of the predator by the prey species is subject to a delay known as the fear response delay,which is incorporated into the *** paper establishes the preliminary conditions for the solution of the delayed model,including positivity,boundedness and *** paper discusses the existence and stability of equilibrium points in the *** particular,the paper considers the discrete delay as a bifurcation parameter,demonstrating that the system undergoes Hopf bifurcation at a critical value of the delay *** direction and stability of periodic solutions are determined using central manifold and normal form ***,the global stability of the model is established at axial and positive equilibrium *** extensive numerical simulation is presented to validate the analytical findings,including the continuation of the equilibrium branch for positive equilibrium points.

关键词： Hopf bifurcation fear effect prey refuge periodic solutions time delay branch off

Layered Potassium Titanium Niobate/Reduced Graphene Oxide Nanocomposite as a Potassium‑Ion Battery Anode

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Nano-Micro Letters 2024年第1期16卷 1-16页

作者： Charlie A.F.Nason ajay Piriya Vijaya kumar Saroja Yi Lu Runzhe Wei Yupei Han Yang Xu Department of Chemistry University College London20 Gordon StreetLondon WC1H 0AJUK

With graphite currently leading as the most viable anode for potassium-ion batteries(KIBs),other materials have been left relatively *** metal oxides are among these,with many positive attributes such as synthetic maturity,longterm cycling stability and fast redox ***,to address this research deficiency we report herein a layered potassium titanium niobate KTiNbO5(KTNO)and its rGO nanocomposite(KTNO/rGO)synthesised via solvothermal methods as a high-performance anode for *** effective distribution across the electrically conductive rGO,the electrochemical performance of the KTNO nanoparticles was *** potassium storage performance of the KTNO/rGO was demonstrated by its first charge capacity of 128.1 mAh g^(−1) and reversible capacity of 97.5 mAh g^(−1) after 500 cycles at 20 mA g^(−1),retaining 76.1%of the initial capacity,with an exceptional rate performance of 54.2 mAh g^(−1)at 1 A g^(−1).Furthermore,to investigate the attributes of KTNO in-situ XRD was performed,indicating a low-strain ***-situ X-ray photoelectron spectra further investigated the mechanism of charge storage,with the titanium showing greater redox reversibility than the *** work suggests this lowstrain nature is a highly advantageous property and well worth regarding KTNO as a promising anode for future high-performance KIBs.

关键词： Potassium-ion batteries Intercalation Transition metal oxides Anodes Nanocomposite

Helicobacter pylori isolated from gastric juice have higher pathogenic potential than biopsy isolates

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Genes & Diseases 2024年第1期11卷 34-37页

作者： Budhadev Baral Dharmendra Kashyap Nidhi Varshney Tarun Prakash Verma ajay kumar Jain Debi Chatterji Vinod kumar Amit Mishra Awanish kumar Hem Chandra Jha Infection Bioengineering Group Department of Biosciences and Biomedical EngineeringIndian Institute of Technology IndoreSimrolIndoreMadhya Pradesh 453552India Choithram Hospital and Research Center IndoreMadhya Pradesh452014India Department of Metallurgy Engineering and Materials Science Indian Institute of Technology IndoreSimrolIndoreMadhya Pradesh 453552India Department of Bioscience&Bioengineering Indian Institute of Technology JodhpurNH 65 Nagaur RoadJodhpur DistrictKarwarRajasthan 342037India Department of Biotechnology National Institute of Technology RaipurGE RoadRaipurChhattisgarh 492010India

Persistent gastritis induced by Helicobacter pylori(***)is the strongest known risk factor for gastric cancer(GC).*** is prevalent in about 50%world's population,while it causes cancer in less than 2%of exposed individuals.1 Our studies found that *** infection can induce oncogenic properties in AGS cells by deregulating multiple factors associated with the cell cycle,apoptosis,and other important events associated with cancer progression.

关键词： H.pylori pylori Helicobacter

Effect of using borax decahydrate as nanoparticles additive in blends of spirulina biodiesel/diesel on combustion characteristics and knock intensity

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CLEAN ENERGY 2024年第3期8卷 62-78页

作者： Singh, ajay Partap Gautam, Puneet Singh IIMT Univ Meerut Mech Engn Dept Meerut 250001 Uttar Pradesh India

In this extensive investigation, the impact of borax decahydrate as a fuel additive in a diesel single-cylinder engine was rigorously examined. Borax decahydrate was introduced at concentrations of 5, 15, 25 and 35 g in 500 ml of biodiesel, forming five unique fuel mixtures with conventional diesel: 90% diesel + 10% spirulina biodiesel (SB10), SB10 + 1 g borax decahydrate (SB10B1), SB10 + 3 g borax decahydrate (SB10B3), SB10 + 5 g borax decahydrate (SB10B5) and SB10 + 7 g borax decahydrate (SB10B7). The investigation encompassed four diverse loading conditions and yielded insightful findings. Notably, at full load, SB10B3 exhibited a higher cylinder peak pressure than diesel, reaching 69.25 bar. Heat release rate profiles demonstrated superior efficiency for SB10 at 50% load, with a cumulative heat release rate of 950 J/degrees CA, which is lower than the 1050 J/degrees CA of diesel. Knock intensity (KI) evaluations revealed that, although SB10 and SB10B1 exhibited higher KI than diesel at full load due to elevated peak pressure, SB10B7 showed no knocking across all loads, indicative of reduced in-cylinder combustion. This meticulous numerical analysis emphasizes the potential of borax decahydrate as a catalyst and enhancer, providing valuable insights into the combustion dynamics of these alternative fuel blends and their viability for sustainable and efficient engine performance. In summary, out of all the blends, SB10B3 could be a potential diesel fuel replacement fuel for compression-ignition engines. The impact of borax decahydrate as a fuel additive is tested in a single-cylinder engine that burned mixtures of diesel and biodiesel derived from spirulina. Five unique mixtures of fuels and additive are used at different engine loads. Graphical Abstract

关键词： spirulina biodiesel borax decahydrate diesel engine combustion knock intensity HRR in-cylinder pressure DIESEL-ENGINE PERFORMANCE REAL-TIME START EMISSION CHARACTERISTICS EXHAUST EMISSIONS OIL CONSUMPTION FEEDSTOCK

Unearthing old rice germplasm,illuminating a new way to improvement

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Journal of Integrative Plant Biology 2024年第6期66卷 1041-1043页

作者： Xiaoming Zheng Ramaiah Venuprasad ajay Kohli International Rice Research Institute Metro ManilaPhilippines

We are on the cusp of a new era,with the global pop-ulation surpassing 8 billion,and over half relying on riceas their staple food(Sasaki and Burr,2000).Despite thisgrowing demand,rice yield per unit has seemingly plateauedfor many years(Song et al.,2022).This stagnation raisesserious concerns about future global food security,especiallyconsidering the shrinking arable land in many countries.

关键词： germplasm plateau spite

Deep Learning-Based Speech Emotion Recognition: Leveraging Diverse Datasets and Augmentation Techniques for Robust Modeling

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Journal of Harbin Institute of Technology(New series) 2024年

作者： Ayush Porwal Praveen kumar Tyagi ajay Sharma Dheeraj kumar Agarwal Department of Electronics and Instrumentation Engineering， Shri G.S.Institute of Technology and Science Department of Electronics and Communication Engineering， Maulana Azad National Institute of Technology School of Computing Science and Engineering， VIT Bhopal University

In recent years， Speech Emotion Recognition (SER) has developed into an essential instrument for interpreting human emotions from auditory data. The proposed research focused on the development of a SER system employing deep learning and multiple datasets containing samples of emotive speech. The primary objective of this research endeavor is to investigate the utilization of Convolutional Neural Networks (CNNs) in the process of sound feature extraction. Stretching， pitch manipulation， and noise injection are a few of the techniques utilized in this study to improve the data quality. The investigation includes coverage of these methods. Feature extraction methods including Zero Crossing Rate， Chroma＿stft， MFCC， RMS， and MelSpectogram are used to train a model. By using these techniques， audio signals can be transformed into recognized features that can be utilized to train the model. Ultimately， the study will produce a thorough evaluation of the model’s performance. When this method was applied， the model achieved an impressive accuracy of 94.57% on the test dataset. Proposed work also validated on EMO-BD and IEMOCAP dataset. These consist of further data augmentation， feature engineering， and hyperparameter optimization. By following these development paths， SER systems will be able to be implemented in real-world scenarios with greater accuracy and resilience.

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