bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Influence of Composite Charge Structure Parameters on Detonation Wavefront
Authors: Lichen Zhao , Jianping Yin , Xudong Li , Jianya Yi
Published: December 2024

In order to study the detonation wave propagation process of the composite charge, the wavefront type, and the relationship between the characteristic parameter α of the composite charge wavefront and the detonation velocity difference of the inner and outer layer explosive. The finite element software was used to numerically simulate and calculate six structural schemes that changed the detonation velocity of the inner and outer layers explosive of the composite charge and the diameter ratio of the inner and outer explosives. The test results show that the composite charge structure with different inner and outer explosive detonation velocities and the diameter ratio of inner and outer explosives has different wavefront propagation processes and wavefront types. When the diameter ratio of the inner and outer explosives in the composite charge structure is the same, the detonation velocity difference between the inner and outer layers of explosives is changed, and the influence law of the incident Angle changes with the change of the detonation velocity difference is found.
Fast calculation method for implosion loads in cylindrical vessels under single explosion source
Authors: Chen G J , Qiu J L , Zhang Y M , Wang S Y
Published: December 2024

Combined with the image explosion source method and LAMBR (LAMB revisied) model, a fast calculation method of wall load of implosion in cylindrical vessels with single explosion source was proposed. The verification results show that the maximum relative errors of the predicted and simulated values of overpressure peak and specific impulse on the structural wall are −13.66% and −17.84% respectively. The predicted overpressure and specific impulse time curves are in good agreement with that obtained by simulation, which can reflect the multimodality of the load at the measuring point under the action of implosion and verify the effectiveness of the method.
Microscopic scale simulation study on the orientation degree of heterocyclic aramid fibers
Authors: Gao Yingying , Li Shuhu , Xu Jingli , Wang Ronghui , Wang Danyong , Zhang Haiyun , Guo Jianfen
Published: December 2024

Heterocyclic aramid fibers have more outstanding heat resistance and higher mechanical properties than pure aramid fibers (without heterocycles). Aromatic copolyamide fibers containing heterocycles are widely used in aviation, aerospace, armor protection, bulletproof vests, and space development due to their outstanding excellent properties. Fiber orientation has a significant impact on the mechanical and physical properties of products. However, the research on micro simulation calculation of fiber orientation is limited to qualitative comparison between different orientation degrees, and cannot quantitatively obtain the value of orientation degree. Therefore, this article mainly studies a new method for micro calculation of orientation degree, and simulates the influence of orientation degree and molecular weight on the Young’s modulus of fibers at the micro scale.
Analysis of the influence of structural parameters of irregular charges on the forming performance of EFP with tail Fins
Authors: Ronghua Ma , Wenbin Li , Peng Chen , Dacheng Gao , Chuanyun Tao , Zhenchao Liang
Published: December 2024

In this study, a special charge structure is designed to form an explosively formed projectile (EFP) with fins for stable flight. By using LS-DYNA for numerical simulation, the influence of charge structure parameters on the EFP characteristics of the tail fins was analyzed. The results show that the irregular charge structure can reliably form an EFP with fins, and the number of EFP tail fins can be controlled by changing the number of sides n of the regular polygon at the top section of the charge. Changing the shape parameters n and Dn of the top section of the charge will greatly affect the shape of the tail fins, while the charge height H has a significant impact on the length to diameter ratio of EFP, the appropriate range of H values should be between 0.5Dc and 0.8Dc. The research results can provide reference for the design ideas of tail wing EFP.
Research on the effect of different tungsten content liner materials on EFP forming
Authors: Wang Hong-Bin , Li Yue , Li Ying , Li Ming-Jian , Xie Meng-Di , Guan Chang , Lin Xue
Published: December 2024

In response to the development of EFP warhead technology at home and abroad, as well as the requirements for long-range and high power in future battlefield environments for EFP warheads, a study was conducted on the influence of different tungsten content liner materials (pure Ta, Ta2.5W, Ta5W, Ta10W) on EFP formation. The results showed that the comprehensive performance of EFP formed by pure Ta, Ta5W, and Ta10W was slightly inferior to Ta2.5W, and Ta2.5W had higher strength and better flight stability, making it an ideal liner material.
Research Progress on the Impact Resistance of Basalt Fiber-Reinforced Polymer Composites
Authors: Zhang Z M , Lu R J , Zhang H , Bai L H , Sun Y J
Published: December 2024

Basalt fibers exhibit excellent properties and have diverse applications. This paper thoroughly investigates the impact resistance of polymer matrix composites reinforced by basalt fibers and analyzes the failure mechanisms during impact, including micro-deformation, delamination, and fiber fracture. Basalt fiber-reinforced resin matrix composites consist of a reinforcement phase, a matrix phase, and an interface phase. To strengthen the material’s resistance to impacts, various approaches have been explored, including optimizing the matrix resin (e.g., selecting vinyl resin and toughening treatments), optimizing the reinforcement phase (e.g., fiber hybridization, morphology optimization, and interlayer hybridization), and improving the interface phase (e.g., coupling agent modification and carbon nanotube grafting). These optimization measures can significantly enhance the impact resistance of basalt fiber-reinforced polymer materials under low-velocity impact loads. Under high-velocity impact loads, increasing the number of laminate layers or employing three-dimensional weaving techniques can significantly improve the material’s impact resistance. These research findings aim to provide a theoretical foundation and practical references for the application of basalt fiber-reinforced polymer materials within the domain of impact resistance.
Numerical simulation study of tungsten alloy segmented rod penetration into steel target
Authors: Guo Xin‐qi , Zhou Tong , Shi Yu‐peng , Chen Zhao
Published: December 2024

Long rod projectile has strong penetration capability due to its high specific kinetic energy, however there exists a limit value to improve its penetration depth by increasing the aspect ratio. A higher penetration efficiency can be obtained by equal-mass segmented rod under certain conditions. Numerical simulation study of tungsten alloy segmented rod penetrating semi-infinite steel target with the speed of 1000m/s-3000m/s was carried out. Penetration process of segmented rods were analysed and compared with the equal-mass long rods. The penetration capability of segmented rods with different number of segments and different speeds on the semi-infinite steel target was studied, and the penetration mechanism was analysed. The numerical simulation results of the ideal segmented rod penetration on thick targets can provide a reference for its practical application.
Erosion and wear of barrel and its impact on projectile force
Authors: Yang Diao , Liu Peng-ke , Di-wu Si-jie , Li Jia-xing
Published: December 2024

During gun firing, the inner surface of the barrel will undergo erosion and wear, leading to changes in the gap between the projectile and barrel. This cause the load environment in which the projectile moves inside the barrel to become more severe, and the cutting and wear of the rotating band increase. Therefore studying the erosion and wear of barrel and its impact on projectile force is of great significance for the lifespan and launch safety of the barrel. By testing the erosion and wear of the barrel with different firing numbers and analysing the anatomy of the end of life barrel, the damage and expansion patterns of the barrel were obtained. On this basis, a coupled dynamic model of projectile and barrel considering erosion and wear was established, and the influence of erosion and wear on the force acting on the motion process of the projectile inside the barrel was calculated. The results indicate that the erosion and wear value of the barrel follows a cubic polynomial along the axis, and the maximum value is located at the commencement of rifling. At the end of the barrel’s life, the engraving resistance of the rotating band is reduced by about 38.7%, the surface contact force between the rotating band and rifling land is reduced by 36.4%, and the impact force between the bourrelet and barrel is increased by about three times.
Modelling and Experimental Verification of the Internal Ballistics Trajectories in Gas Combustion Explosion Ejections
Authors: Ren Jie , Bi Shuo , Yao Lin , Lin Guowen
Published: December 2024

The internal ballistic process and flow field were examined in the context of the launch of hydrogen-oxygen bipropellant explosives. This was achieved through the establishment of an internal ballistic launch model, which employed the high-low pressure launch principle. This approach diverges from the conventional tenets of internal ballistic theory, wherein a combustible gas is employed in lieu of a propellant for the purpose of launch. Furthermore, a high-low pressure chamber scheme was devised with the objective of mitigating the overload peaks that are typically encountered during the launch process. A fluid simulation was employed to conduct a virtual analysis of the flow field alterations within the high-low pressure chamber during the launch of a hydrogen-oxygen bipropellant explosive utilizing the internal ballistic model. The pressure variations over time within the high-low pressure chambers throughout the launch process were investigated, and the results were supplemented with load motion and physical ejection experiments. The results demonstrated that the simulated and calculated curves exhibited slight elevation relative to the real curve under identical conditions, yet remained within an acceptable range of error. Our study successfully validated the feasibility of utilizing hydrogen-oxygen combustion launch schemes for small load ejection, offering a valuable reference point for future research and optimization in this domain.
Analysis of transformer moisture treatment based on DIRANA dielectric spectrum analyzer
Authors: Chen Qiong , Zhao Wenlin , Chen Lili , Hu Siyu
Published: December 2024

Transformer is the infrastructure of power transmission and distribution, which is widely used in various fields. Its good insulation performance guarantees its safe operation. Water content is one of the critical factors affecting the insulation performance of transformer, so monitoring transformer water content is particularly important. In the case of transformer damp accident at a hydropower station, the transformer water content field test analysis test, combined with the transformer insulation test and transformer conventional/special test results, verified the validity and accuracy of the test results of the DIRANA dielectric spectrum analyzer. It provides a theoretical basis for the broadband and non-destructive testing of transformer water content and has a guiding significance for the field diagnosis of transformer insulation performance.
Joint resource optimization method for integrated sensing and communication system based on communication rate maximization
Authors: Niu Weigang , Xie Jianli
Published: December 2024

As wireless communication tech swiftly evolves, Integrated Sensing and Communication (ISAC) systems are increasingly garnering attention in research. This document suggests a collaborative resource optimization technique for ISAC, centered on maximizing communication rates, with the goal of enhancing communication speeds and optimizing system efficiency through fair distribution of system resources. The article begins by examining the fundamental structure and principles of a communication-aware integrated system, followed by the development of a resource optimization model reliant on the rate of communication. For the resolution of this non-convex optimization issue, a refined genetic optimization algorithm iteratively fine-tunes the subcarrier and power resources. The simulation findings demonstrate the method’s ability to enhance communication efficiency and lessen the energy usage of the system.
Room-Temperature Ethanol Sensing by PVA/ZnS/ZnO:Fe Nanocomposite Synthesized by Chemical Precipitation Technique
Authors: Gogoi Arista , Bhattacharjee Suparna
Published: December 2024

In this work, we report the synthesis of PVA/ZnS/ZnO:Fe core/shell nanocomposite using the chemical precipitation method. The core/shell structure offers several advantages for gas sensing, including improved gas adsorption, selectivity, and stability. Polyvinyl alcohol (PVA) has been used as the matrix while Zinc Chloride (ZnCl2) and Sodium Sulphide (Na2S) has been used as the precursors for the synthesis of ZnS nanoparticles. For the synthesis of ZnO nanoparticles, Polyvinyl alcohol (PVA) has been used as the capping agent and Zinc Nitrate (Zn (NO3)2) and Sodium Hydroxide (NaOH) have been employed as the precursors. In the work, one PVA/ZnS/ZnO:Fe sample has been synthesized with a constant concentration of Fe doping, maintaining a constant reaction time. Characterization of the synthesized sample is achieved through UV-visible Spectrophotometry (UV-vis), Photoluminescence Spectrophotometry (PL), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Analysis of X-ray (EDAX) and Transmission Electron Microscopy (TEM) respectively. From the characterization results the formation of PVA/ZnS/ZnO:Fe core/shell nanocomposite is confirmed. The XRD pattern has been used to determine the crystalline nature and size of the crystal. SEM images reveal more or less cloudy-like nanostructure in PVA/ZnS/ZnO:Fe samples. After that, the selectivity study of the synthesized sample towards various gases was done. Accordingly, ethanol was chosen and a sensitivity study of the synthesized nanoparticles was performed in the presence of ethanol gas.
Morphological Study of Early-Stage Biomimetic Carbonated Hydroxyapatite Coating Development on Sputtered ZnO Thin Films
Authors: Rajkumar Pradhyut
Published: December 2024

For a deeper understanding of crystal nucleation, development, and alteration on crystalline substrates, hydroxyapatite films on sputtered ZnO are formed. The substrates used were as-deposited nanostructured ZnO thin films on glass. These films were produced by pulsed DC magnetron sputtering, as described in one of our previous works and then immersed in a calcifying solution for 24 hours to allow for hydroxyapatite nucleation and production. The calcifying solution combines equal volumes of aqueous calcium (7.5 and 10 mM) and carbonate-containing phosphate (4.5 and 6 mM) solutions at 37 °C with a pH range from 7.2 to 7.4. According to Field Emission Scanning Electron Microscopy (FESEM) analyses, the substrate type (sputtering power) and the concentration of the precursors used in the preparation of the calcium and carbonate-containing phosphate solution influence the structure and morphology of the hydroxyapatite films. Furthermore, using ZnO thin films deposited on glass made at lower sputtering powers as substrates results in a denser nanocrystalline hydroxyapatite coating than that grown on ZnO thin films sputtered at higher sputtering power. The nucleation of hydroxyapatite onto substrates is controlled by both charged surfaces and the supersaturation of the calcifying solution, with larger concentrations of the precursor solutions producing thicker films.
Exploration of the dielectric properties in Na2Co2TeO6 through Impedance Spectroscopy
Authors: Maurya Amit , Pal D
Published: December 2024

We have investigated the dielectric and electrical properties in a non-centrosymmetric honeycomb lattice compound Na2Co2TeO6. The electro-active zones identified through impedance spectroscopy within the frequency range of 100Hz – 1MHz are explained by the presence of both grains and grain boundary phases in the microstructure of Na2Co2TeO6. The alteration of impedance plane plots has been discussed in connection with the change in relaxation time at different temperatures. The analysis of the Nyquist plot indicates a substantial contribution of grain boundary resistance to the total resistance. We have observed a quasi-semiconducting type of properties in the variation of grain resistance with temperature, arising due to the oxygen vacancy in the path (Co2+-O-Na1+-O-Co2+). An examination of the electrical transport characteristics of Na2Co2TeO6 indicates a pronounced frequency dependency, indicating the motion of the charge carriers arises due to correlated barrier hopping.
CdS-Titania nanocomposite: An improved visible active photocatalyst for dye degradation
Authors: Banerjee Nisha , Nair Ranjith G
Published: December 2024

Photocatalysis is emerged as a feasible solution for addressing the issues related to green energy production and sustainable environment. Among various reported photocatalysts, Titania is one of the widely used one due to its high stability, and low cost. However, its wide band gap and poor charge separation limits its photocatalytic performance in the UV region only. Coupling of Titania with suitable visible active semiconductor is a proven strategy to improve the performance. In this context, CdS-Titania (Anatase) nanocomposite has been synthesized via facile hydrothermal route and its impact on photon absorption and carrier separation efficiency were studied. The synthesized samples were characterized through various structural, optical and electrochemical analysis. X-ray diffraction pattern confirms the formation of CdS-Titania (Anatase) composite and its physicochemical properties. FE-SEM confirms the disintegration of CdS microspheres into smaller agglomerated particulates. The absorption spectroscopy confirms that induction of CdS improves the visible light absorption capacity. The composite consisting CdS-Titania (Anatase) (CdSA) shows the maximum red shift in the visible range. The low charge transfer resistance of composite observed in EIS analyses further confirms the proper separation of charge carriers at junction. The photocatalytic degradation performance under visible light irradiation was performed and found that the nanocomposite performs better than the pristine Anatase and CdS. CdSA has been found to have superior photocatalytic ability. It shows 43 times and 1.52 times better performance than pristine Titania and CdS respectively. This can be attributed to the enhanced visible photon absorption achieved through the successful formation of heterojunction. This opens up a new area of research for improving the performance of pristine Titania.
Influence of Capping Agents for Controlling Structural and Optical Properties of Copper Chalcogenide (CuS) Nanoparticles
Authors: Khongiang Longkhraw , Deb Sujata , Kalita P. K.
Published: December 2024

Copper based chalcogenides have attracted considerable attention in recent years due to their exclusive properties that are tunable by the structure, stoichiometry and composition. Among the categories of chalcogenides, copper sulfide (CuS) has been the subject of extensive research as it exists in various stable phases. The present work emphasizes on the impact of capping agents: aloe vera and polyvinyl alcohol (PVA) on structural and optical properties of CuS (covellite) nanoparticles. Structural characterization of the as-synthesized CuS/PVA and CuS/Aloe vera nanoparticles is done using X-ray diffraction (XRD) while their morphology is examined with Field Emission Scanning Electron Microscopy (FESEM). The chemical stoichiometry of synthesized CuS nanoparticles is performed using Energy Dispersive X-ray Spectroscopy (EDS). UV-Vis absorption and photoluminescence (PL) spectroscopy are employed to study the optical properties. The XRD shows the presence of diffraction peaks for CuS. The average crystallite size calculated for the prepared CuS/PVA and CuS/Aloe vera nanoparticles using Debye Scherrer’s equation are 4.59 nm and 3.58 nm respectively. Band gap calculation from Tauc’s plot showed the corresponding direct optical band gap of the synthesized CuS/PVA and CuS/Aloe vera nanoparticles to be 2.87 eV and 3.75 eV, indicating blue-shift due to quantum confinement. Photoluminescence spectra of as-synthesized samples indicated strong emission at 467 nm for both the samples: CuS/PVA and CuS/Aloe vera. Optical properties of the as-synthesized nanoparticles showed that they are promising materials for optoelectronic devices. Aloe vera, the environment friendly and non-toxic agent is found to be a suitable “green” passivator in stabilizing CuS nanoparticles.
Exceptional Photodegradation Efficiency of Eu3+: GdVO4 Against Methylene Blue and Methyl Orange Textile Dye Mixtures
Authors: Ashiihrii Kapani , Boro Bhaben , Ansari Aftab
Published: December 2024

We report on efficacy of Eu3+ doped GdVO4 nano system as an effectual photocatalytic agent for textile dye degradation. The nano system synthesized via one step solid state method displayed band gap of the nano system determined to be ~3.5 eV which can be considered suitably apt for usage in photocatalytic reactions. Photocatalysis is one of the leading technologies so as to facilitate degradation of textile dye wastes. Most of the dyes used display harmful nature to the ecology if left untreated. Among the various dyes, Methylene Blue (MB) and Methyl Orange (MO) dyes were chosen as the target citing their high usage in textile industry. Most of the textile dyes used seep into the drainage wherein they remain in a mixed phase leading to complex chemical structure and hence raising problems in degradation process. In a first, we describe the degradation upon mixing the two dyes together. Our findings demonstrate the remarkable capability of the photocatalytic process facilitating ~61% and ~33% degradation in the Methylene Blue and Methyl Orange respectively. Interestingly, upon subjecting the photocatalyst into the mixture the photodegradation rose up to ~ 87% for MB and ~45% for MO in their mixed phase. Hence proving the system to be more effective in dye mixtures. The changes in the molecular structure upon degradation was analyzed using FTIR spectroscopic studies. We observed formation of intermediates upon the catalytic reaction that add to the degradation process. The degradation rate saturation in the degradation process was reached by ~240 min. The comprehensive report on effect of RE dopant in RE based vanadate matrix would provide new insights to resolve existing concerns in addressing issues relating removal of organic contaminant posing environmental threat and also carry multi-functional scope in industrial relevance.
Analysis of FUV Emission in the Vicinity of R136 Cluster in 30 Doradus
Authors: Dev Barenya Kumar , Saikia Gautam , Bordoloi Olag Pratim , Shalima P. , Gogoi Rupjyoti
Published: December 2024

The intense diffuse radiation of galactic systems in the far ultraviolet (FUV) range is primarily due to dust scattering, with properties such as albedo, scattering phase function, and optical depth playing a crucial role. Utilizing observed data from the Far Ultraviolet Spectroscopic Explorer (FUSE) telescope, we investigated dust-scattered diffuse FUV emission from the 30 Doradus nebula in the Large Magellanic Cloud (LMC), offering insight into interstellar dust properties essential for understanding starburst galaxies. Employing a simple spherical shell model in the Monte Carlo based radiative transfer tool SKIRT, we simulated the dust-scattered FUV emissions, and compared them with the observed data. We predicted an excess of FUV photons being scattered near the star cluster R136 (formerly RMC 136) and ascertained a robust linear correlation between observations and model. Additionally, our best-fit model predicted the hydrogen column density near R136 to be approximately ~ 4.36 × 1021cm−2, corresponding to a color excess of E(B − V ) = 0.2, with the contribution of diffuse scattered FUV emissions estimated at 13% of the total radiation. This model can be further extended to better understand dust properties of similar starburst environments in the local universe and beyond.
Study of Neutrino Mass Matrix with One Vanishing Subtrace using Trimaximal Mixing
Authors: Dey Sangeeta , Kumar Priyanka , Patgiri Mahadev
Published: December 2024

In this work we study the phenomenological implications of neutrino mass matrix with one vanishing subtrace using trimaximal mixing matrix, TM
1. Here, we have analysed only two patterns of one vanishing subtrace i.e., S
11 = 0 and S
12 = 0. We find that the two considered patterns accommodate the present neutrino oscillation data for both Normal Hierarchy and Inverted Hierarchy. For both the patterns, we present the correlation plots of the neutrino oscillation parameters and calculate the effective Majorana mass, hence study the neutrinoless double beta decay rate.
Semi-Analytical Study of Charged-Current νN scattering cross-section with High Energy and Ultra High Energy Probes
Authors: Bora Deep Jyoti , Imtiaz Raisa , Devee Mayuri
Published: December 2024

In this study, we investigate the cross-section of neutrino-nucleon scattering in both the high-energy (100–700 GeV) and ultra-high-energy (108–1013 GeV) regimes. This analysis aims to provide deeper insights into the weak interaction processes involving neutrinos, a particle that remains elusive in many aspects. Our work contributes to the theoretical understanding and determination of neutrino-nucleon cross-sections. At high energies, our results exhibit slight deviations from previously available data but remain consistent with established trends. At ultra-high energies, our analytical results show strong agreement with those reported in the literature. Additionally, we suggest that incorporating higher-order QCD corrections could further improve the accuracy of our results.
An Experimental Study of Stable and Chaotic Structures in a Plasma System Analogous to Earth Magnetosphere
Authors: Goswami J. , Goswami D. , Chutia B. , Kausik S. S. , Saikia B. K.
Published: December 2024

In recent years, studies on magnetospheric plasmas have increased drastically. Different theoretical models are proposed to match the data observed from various space missions. Still, no sufficient experimental setup is there to replicate the formation like a double layer in these kinds of plasma. In this study, we have made an experimental setup that nearly replicates the magnetospheric plasma environment. We have placed a stainless steel (SS) plate inside our plasma chamber. The argon plasma is produced in the hot cathode discharge method at comparatively high pressure. Then a positive bias is applied to the SS plate with and without attaching a permanent magnet. This positively biased SS plate creates a fireball and firerod-like structures in the absence and presence of the magnet, respectively. This scenario is analogous to the Earth’s magnetospheric plasma and the SS plate represents the pole of the Earth. In this plasma, we have studied the axial variation of ion density (ni
), electron temperature (Te
), electron energy distribution function (EEDF), and the plasma potential for both cases. Lastly, we have discussed the nature of the plasma potential variation with a theoretical model.
Soliton Dynamics of a Gauged Fokas-Lenells Equation Under Varying Effects of Dispersion and Nonlinearity
Authors: Dutta Riki , Talukdar Sagardeep , Saharia Gautam K. , Nandy Sudipta
Published: December 2024

Davydova-Lashkin-Fokas-Lenells equation (DLFLE) is a gauged equivalent form of Fokas-Lenells equation (FLE) that addresses both spatio-temporal dispersion (STD) and nonlinear dispersion (ND) effects. The balance between those effects results a soliton which has always been an interesting topic in research due to its potential applicability as signal carrier in information technology. We have induced a variation to the dispersion effects and apply Hirota bilinear method to realise soliton solution of the proposed DLFLE and explore how the soliton dynamic behaves in accordance to the variation of the dispersion effects. The proposed equation is applicable for number of systems like ultrashort optical pulse, ion-cyclotron plasma wave, Bose-Einstein condensate (BEC) matter-wave soliton under certain external fields, etc. The study on such systems under varying effects is very limited and we hope our work can benefit the researchers to understand soliton dynamics more and work on various other nonlinear fields under varying effects.
Supercontinuum generation in Rubidium vapour
Authors: Ali Rezzak , Kakum Buru , Marngar Rickey , Mukherjee Rohit , Borgohain Nitu
Published: December 2024

We present a theoretical study of supercontinuum generation in a Rubidium vapor cell under the conditions of electromagnetically induced transparency (EIT). A weak probe pulse and a strong control laser beam were utilized within a lambda-type excitation scheme. We identified a significant Kerr nonlinearity on the order of 103 W−1m−1 and low group velocity dispersion on the order of 10−20 s2m−1 in the Rubidium vapor cell of length 2.54 cm at a probe wavelength of 781 nm. These parameters facilitated the generation of a 35nm supercontinuum, characterized by pronounced oscillations resulting from self-phase modulation and optical wave breaking. The findings suggest potential applications in nonlinear optical devices and spectroscopy.
Kerr-Quintic Nonlinearities in Graphene Quantum Dot
Authors: Shayam Abhijit , Nath Monika , Mukherjee Rohit , Borgohain Nitu
Published: December 2024

This paper deals with the higher-order nonlinearities in graphene quantum dots as defect layer in one dimensional photonic crystal. A weak probe pulse and two strong control laser beams are employed in a close loop ladder type configuration under an electromagnetically induced transparency regime. In the system, the existence of third- and fifth-order susceptibilities are found to be as large as ~10−15
m
2/V
2, and ~10−27
m
4/V
4, respectively, at the probe wavelength 1.55 μm. The systems possessing such large nonlinearities can be employed to fabricate nonlinear optical devices, operable at much low power level.
Observation of coexistence of low and high frequency oscillations with reduced neutral density in a linear plasma device.
Authors: Bora Dibyajyoti , Tarafder Aritra , Biswas Subir
Published: December 2024

A linear plasma device has been developed at IASST producing uniform and quiescent (δne/ne
< 0.5%) laboratory plasma for performing basic wave and instability experiments in a precise manner. Uniform plasma produced in the device is very quiescent (δne/ne
< 0.5%) in nature in a wide neutral pressure range of ~ (3 − 6) × 10−4 mbar. However, beyond this neutral pressure range, onset of plasma instabilities leads to increase density fluctuations, thereby raising the value of δne/ne
and reducing the degree of plasma quiescence. Recorded floating potential fluctuations with an array of Langmuir probes indicate the coexistence of low and high frequency oscillations at lower neutral pressure range. The nature of these plasma instabilities appear to be similar to those observed in the plume mode of hollow cathode discharges. A linear plasma device will facilitate the investigation of these self-excited oscillations in a controlled environment.
Firefly flash model: A Physics-Informed Neural Network (PINN) based analysis
Authors: Saikia Debashis
Published: December 2024

The concept of Physics-Informed Neural Network (PINN) is relatively new and it has evolved as an effective tool in solving complex problems having high degree of uncertainties. Also, the advantage of PINN is that it can determine unknown parameters for a given dataset. Here, we have successfully applied the concept of PINN to the PirePly Plash model, which is a low dimensional robust nonlinear model developed from the chemical enzymatic reactions responsible for the light emission of the PirePly[1]. The parameters of the underlying mechanism have been estimated using the PINN method. The PINN-based prediction of the reaction rates shows a good agreement with the available results.
Modeling Techniques for Estimating Soil Radon Concentrations
Authors: Borgohain Devashree , Jaishi Hari Prasad , Singh Sanjay , Tiwari Raghavendra Prasad , Tiwari Ramesh Chandra
Published: December 2024

This paper describes the comprehensive analysis of soil radon concentrations through the application of the Auto Regressive Integrated Moving Average (ARIMA) Model. The study utilizes information on radon gathered from March 2013 to May 2016, employing LR-115 type II detectors. Radon and thoron, prominent constituents of natural radioactivity in the Earth’s crust, are pivotal subjects in geophysics and indoor measurements. The investigation focuses on deriving the predicted values of radon concentrations, employing various ARIMA models. Specifically, four distinct models: ARIMA (3, 0, 7), ARIMA (4, 0, 7), ARIMA (3, 0, 6), and ARIMA (4, 0, 6) are constructed. Evaluation of the auto-correlation function (ACF) and partial auto correlation function (PACF) plots suggests that ARIMA (3, 0, 7) and ARIMA (4, 0, 7) stand out as promising candidates for effectively capturing the data dynamics. To validate the efficacy of each model and ascertain the most suitable one, a comparative analysis between the estimated and real values is conducted. This involves the implementation of a linear fit test and an F-test. The statistical results decisively indicate that ARIMA (3, 0, 7) outperforms ARIMA (4, 0, 7), establishing its superiority as a better model to forecast radon in soil concentrations in the given time series data. This comprehensive approach demonstrates the significance of precise predictive models in spotting deviations in time series datasets and advances the understanding of soil radon variation.
Properties of ultrathin BSA films interacted by monovalent ions
Authors: Sarkar Sanu , Kundu Sarathi
Published: December 2024

The current study explores the properties of pure alongside monovalent Na+ ions interacted ultrathin films of bovine serum albumin (BSA) immobilized on hydrophilic and hydrophobic solid silicon (Si) surfaces. Such ultrathin BSA films were prepared by dip coating method, and then their structural, morphological, and hydrophobic properties were obtained using X-ray reflectivity (XRR), atomic force microscopy (AFM), and water contact angle (WCA) analysis, respectively. Pure BSA solution helps to deposit pure BSA ultrathin monolayer films of BSA molecules in their native globular shape in tilted alignment on hydrophilic Si and an almost identical tilted monomolecular layer of molecules of BSA is deposited on hydrophobic Si also but tilting is higher implying the deposition of thicker and denser BSA ultrathin layer. Monovalent ions-interacted BSA solution helps to deposit an ultrathin bilayer film on hydrophilic Si, which consists of a side-on oriented bottom layer and a less tilted top layer of BSA molecules, while on hydrophobic Si, an ultrathin bilayer of BSA molecules consisting of tilted bottom and a top layer of BSA molecules was immobilized. Thus, higher immobilization of molecules of BSA has occurred on hydrophilic Si and also on hydrophobic Si due to the incorporation of monovalent ions in the BSA solution. The globular form of the BSA molecules is displayed by pure as well as ions interacted films of BSA on both surfaces. A sessile drop WCA study is employed to explore its hydrophobic properties. All ultrathin BSA films showed WCAs ≥ 60° and higher WCA implying higher hydrophobicity is recorded for monovalent ions-interacted ultrathin BSA films compared to pure BSA films. The incorporation of monovalent ions in the BSA solution facilitates higher immobilization of BSA molecules to help to deposit thicker ultrathin film and, at the same time, helps to expose their inner hydrophobic region towards the outer free surface, contributing to the increment in hydrophobicity.
Assessment of the CORDEX-CORE Models in Simulating the Length of Rainy Season (LRS) over Northeast India
Authors: Das Simanta , Mahanta Rahul , Goswami BN
Published: December 2024

The Length of Rainy Season (LRS) in Northeast India (NEI) is longer than that over other parts of the country and contributes to the seasonal quantum of rainfall, a hallmark of the Indian Summer Monsoon. Low-resolution global general circulation models (GCMs) underestimate rainfall annual cycle over NEI due to unresolved regional orography requiring downscaling with the Coordinated Regional Climate Downscaling Experiment (CORDEX) models for South Asia. However, the uncertainty in CORDEX simulations of the annual cycle of rainfall and its intensity of over NEI due to biases in simulating the LRS is unknown. This study evaluates performance of CORDEX climate models, focusing on their ability to simulate the LRS. Utilizing an objective metric based on the change of sign in a north-south gradient of tropospheric temperature, we define LRS and employ ERA5 reanalysis data as a proxy for observations to establish a benchmark for the historical period of 1979-2005. Our analysis reveals that the CORDEX models when forced by ERA-Interim data, exhibit a consistent positive bias of approximately 6 days, while models forced by General Circulation Models (GCMs) display a negative bias of 10 days. Additionally, both model sets indicate a reduction in bias over inter-annual timescales. Further, we have observed that RCMs forced by ERA-Interim boundary conditions tend to overestimate the thermodynamic index of the Indian summer monsoon (TISM) compared to RCMs forced by GCMs. Our findings suggest that significant discrepancies in the simulation of the upper atmospheric conditions over the South Asia domain by regional models contribute to the pronounced biases in LRS estimates over NEI forced either by observations or by GCM outputs. This study underscores the complexities of accurately simulating the LRS using regional climate models, emphasizing the need for improved methodologies to precisely forecast LRS. Such improvements are crucial for reliable climate change impact assessments over NEI.
Spectrophotometric-based Estimation of Plant Chlorophyll Content using Smartphone
Authors: Das Priyanka , Goswami Smitakshi , Nath Pabitra
Published: December 2024

Estimation of plant chlorophyll concentration plays a major role in determining the health of a plant. Although many devices are available, the existing tools cannot be easily used for in-field estimation due to their sophistication and bulky nature. This work reports a new cost-efficient and portable sensing tool based on a spectrophotometric method for the estimation of chlorophyll content in rice plant leaves using a smartphone camera. Simple optical and electronic components are used for development of the sensing device and all the optical components are arranged in a 3D printed cradle that is attached to the smartphone camera. Based on the well-known complementary color theory and the RGB color model, the chlorophyll content in rice plant leaves has been estimated by the developed sensor and the obtained results are compared and validated with the standard method of chlorophyll estimation.
Attribute of antibacterial response of Black turmeric at different temperatures supported by light scattering signature
Authors: Hussain Farhana , Jaishi Hari Prasad , Roy Sanchita
Published: December 2024

Light scattering is a key technique for analyzing particle properties across various scientific fields. It measures scattered light intensity as a function of angle, applicable to particles ranging from nanometers to micrometers. We carried out a light scattering investigation on black turmeric, which is an antibacterial compound. We investigated black turmeric against Escherichia coli (ATCC-9637) with standard biochemical methods and confirmed its antibacterial and light scattering techniques. Antibacterial activity and light scattering measurements were conducted at various temperatures: 37°C, 45°C, 55°C, and 65°C. Significant changes in the antibacterial activity of the sample and light scattering profiles exhibited at 65°C when compared to that of 37°C. The scattering profiles of these samples demonstrated unique characteristics, highlighting light scattering as a valuable non-invasive alternative for assessing the antibacterial properties of black turmeric.
Simulation of Neural signal by solving coupled differential equation of the FitzHugh-Nagumo model using electronic circuits
Authors: Deka Bandita , Tiru Banty
Published: December 2024

Implementation of neural signals in electronic circuits is indispensable for studying the function of neurons, developing therapies, designing brain-computer interfaces, and artificial intelligence. This paper presents an electronic circuit implementation of neural signal modelling using operational amplifier-based analog computation. The coupled differential equation of the FitzHugh-Nagumo (FHN) model is solved by implementing the circuit in LT Spice software and analysed. The results show that the neural membrane potential can be generated using suitable values of the circuit components and bears close resemblance to the actual. Neural signals in the frequency range 7.29mHz-2.46 Hz are obtained by changing the circuit parameters. This approach provides valuable insight into the simulation of neuronal signalling and offers a basis for hardware implementation for signal generation for various applications.
The Effect of Four Types of Heat Treatment on the Mechanical Properties of Al 6351 Alloy
Authors: Rajesh G , Abdur Rahman M , Jeavudeen S
Published: December 2024

The present research focuses on examining the alterations in the microstructural characteristics and mechanical properties of Al 6351 alloy as a result of various thermal treatments. Four distinct processes were analyzed: solution treatment followed by quenching and aging (T6), retrogression and re-aging (RRA), high-temperature pre precipitation (HTPP), and a modified version of RRA involving interrupted aging. The T6 treatment produced the finest dispersion of precipitates, achieving maximum ultimate tensile strength (UTS) of 320 MPa and yield strength (YS) of 270 MPa; however, it decreased ductility to 12% due to limited dislocation movement caused by the precipitates, which were shown to become immobilized at high concentrations. The RRA treatment exhibited a slight improvement in yield strength, resulting in UTS and YS of 290 MPa and 10% elongation, respectively, as a consequence of a finer and more uniform precipitate distribution after re-aging. HTPP, on the other hand, demonstrated a reduction in strength compared to T6, with UTS and YS at 310 MPa and 260 MPa, respectively, attributed to precipitate coarsening occurring during pre-aging at elevated temperatures. The increasing ductility trend of 13% was associated with initial GP zone size. The modified RRA process yielded the highest strength levels, reaching UTS of 350 MPa, YS of 300 MPa, and an enhanced toughness reflected in improved impact energy of 20 J, likely due to the denser alignment of precipitates; however, it showed slightly lower elongation of 11% than T6 or RRA. The tensile fracture behavior was elucidated through FESEM-based fractography analysis, which revealed cracks propagating uniformly along the length. The results of this investigation highlight the necessity of precisely controlling heat treatment parameters to achieve specific mechanical properties in Al 6351. This research provides valuable insights into managing strength, ductility, and toughness via solid solution grain size distribution and the density of Mg2Si precipitates, which is beneficial for selecting appropriate heat treatments across various industries.
An experimental investigation into the Mechanical properties of jute Fiber / nano-sized ZrC Polymer Composites
Authors: Pavendhan R. , Sriram D. , Irudayaraj Ambrose Edward , Vijayan S. , Chanakyan C.
Published: December 2024

Jute fibre, known for its sustainability and abundance, has been explored as a promising reinforcement in composite materials. This study explores the enhancement of mechanical properties in jute fibre composites through the incorporation of Zirconium carbide nano particles at varying concentrations (0, 2, 4, and 6 wt%). A comprehensive evaluation was conducted to assess hardness, flexural strength, tensile strength, and impact resistance, with a focus on their applicability in high-stress environments. Results indicate that the addition of Zirconium carbide nano particles significantly improves the mechanical performance of the composites. Specifically, increased nano particle concentration leads to enhanced hardness, resulting in superior indentation resistance. Flexural strength tests demonstrate marked improvements in stiffness and resistance to deformation, positioning these composites as promising candidates for structural applications. Tensile testing reveals that higher Zirconium carbide content boosts load-bearing capacity, while enhanced impact resistance suggests improved durability and shock absorption. These findings highlight the potential of Zirconium carbide-reinforced jute fibre composites for various industries requiring high-strength materials, including automotive, aerospace, construction, and sports equipment manufacturing. This method effectively combines sustainability with enhanced mechanical properties. The micro hardness, flexural strength and impact strength of jute/epoxy/6wt.%ZrC was 26.6 %, 51 % and 15.2 % higher than its non reinforced jute/epoxy polymer composites.
Analyzing Experimentally the Dynamic Characteristics of Journal Bearings Under Various Load Conditions
Authors: Moorthy Appusamy Anandha , Madheswaran Subramaniyan , Ganesh Babu L , Murthi M K , Nanthakumar S , Senthilkumar Kallipatti Laxmanan , Selvakumar Andiappan
Published: December 2024

This paper aims to experimentally assess the performance of plain bearings casted as self-lubricating composite materials. Metal stir casting is used to prepare plain bearings based on composite materials, which are made of AA 2218 Al alloy, 4% MoS2, and 15% fly ash. Arrangement of shafts in the textile industry is reflected in the impression of the experimental setting, which was derived from earlier literature. To obtain vibration signals, the DAQ kit and accelerometer were connected using the Laboratory Virtual Instrument Engineering Workbench (LAB-view) as a graphical data collection and interpretation system. Different loads were applied to journal bearings with and without lubrication. The outcome demonstrates the amplitude fluctuation, temperature rise, and mass loss of journal bearings for Gun metal (Red brass), AA2218, and self-lubricating composite materials.