bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dielectric properties and ac conductivity of CuO and Fe2O3 doped polycarbazole nanocomposites
Authors: Raghavendra B , Sankarappa T , Malge Amarkumar , Heerasingh Mohansingh , Devidas Ashwini 
Published: August 2022

Abstract
This paper presents results and discussion on dielectric and ac conductivity of Polycarbazole (PCz) and its PCz/CuO and PCz/Fe2O3 nanocomposites. Samples were prepared by oxidation method using ammonium persulfate as oxidizing agent. Samples were confirmed to be crystalline. Dielectric parameters are observed to be decreased with increase of frequency and temperature. Ac electrical conductivity of pure polycarbozole was found to be more than the composites. Further, conductivity increased with loading of metal oxide nanoparticles. The conductivity of all the samples is found to vary from 10-6 (Ωm)-1 to 10-4 (Ωm)-1 with the temperature (303K- 423K) and exhibited semiconducting nature. This has been ascribed to rise in the number of charge clusters inside polymer matrix with increase of metal oxide content and which in turn adds more polarons to the conduction band and, that increase conductivity. Activation energy for conduction is determined to vary from 1.07 meV to 6.17 meV for PCz/CuO systems and 0.82 meV to 4.06 meV for PCz/Fe2O3 composites. It is for the first time that Polycarbazole and Polycarbazole metal oxide doped nanocomposites have been studied for dielectric properties and ac conductivity over wide a range of frequency and temperature and analyzed data with respect to frequency, temperature and metal oxide content.
Effect of printing parameters on the hardness of 3D printed poly-lactic acid parts using DOE approach
Authors: Maguluri Nagarjuna , Suresh Gamini , Guntur Sitaramanjaneya Reddy 
Published: August 2022

Abstract
Fused deposition modeling (FDM) is an extensively used method for additive manufacturing of thermoplastic materials. It is growing in a variety of engineering applications because of its ability to produce complicated structural designs with low manufacturing time. However, the mechanical characteristics of the 3D printed components are extremely dependent on the proper selection of the printing conditions. In this present work, the impact of three foremost printing parameters, including fill density, extrusion temperature, and printing speed, is examined on the hardness of poly-lactic acid (PLA) parts. Taguchi design of experiment (DOE) methodology is used to minimize the total experimental runs and evaluate the optimal printing parameters for the maximum hardness of the printed part. Analysis of S/N ratios is utilized for establishing the optimal printing parameters, and the corresponding percentage contribution of control factors is measured using ANOVA. The study results have shown that extrusion temperature profoundly influences the hardness of the 3D printed PLA specimens, while printing speeds have a much smaller impact on it.
Finite element analysis of viscoelastic media used in abrasive flow machining process
Authors: Mangesh Gharat Saurabh , Misra Aviral 
Published: August 2022

Abstract
The surface roughness of a part is the most important parameter in view of tribological applications and it also affects the working life of the part during application. The abrasive flow machining (AFM) process is an advanced non-conventional finishing process, used to deburr, polish, and to remove the recast layer from the surface as well as at the edges of the components. In AFM viscoelastic media is used to finish the workpiece with close dimensional tolerance and precision. The viscoelastic media used in the AFM process is laden with abrasive particles. In the present work, a finite element analysis of viscoelastic abrasive media is performed considering the AFM process. A mixture of polyborosiloxane and silicon carbide is used as viscoelastic abrasive media and the AFM process is modeled using ANSYS Polyflow. In the analysis, the flow of viscoelastic abrasive media is assumed to follow the Maxwell model of viscoelastic fluid. The simulations were performed for varying the extrusion pressure for the finishing of an internal cylindrical surface. The results of the simulations were validated with the experimental observation and found in good agreement.
Non-linear analysis of orthotropic hyperelastic plate using VAM
Authors: Burela R G , Bhadoria S K , Harusampath D 
Published: August 2022

Abstract
An asymptotically accurate zeroth-order constitutive relation between 2D strains and stress tensor for an orthotropic hyperelastic material is derived using the Variational Asymptotic Method (VAM). Material nonlinearity is encompassed through the hyperelastic material model while geometric nonlinearity is by allowing finite displacements and rotations. Moderate strains of order 20% are considered. The small parameters such as the ratio of thickness to characteristic dimension, and maximum allowable strain (0.2) separate strain energy density into different orders. The analysis starts with the 3D strain energy density function and is divided into the thickness analysis (1D) and mid-surface analysis (2D). The 1D analysis leads to analytical expressions for warping functions, constitutive relations, and recovery relations. The 2D analysis is based on a non-linear finite element method that takes the constitutive relation as its input and obtains 2D displacements. The recovery relation converts them to 3D field variables i.e. displacements, strains, and stresses. The theory is applied to a square clamped plate subjected to uniformly distributed pressure. The results are accurate and obtained in a computationally efficient manner.
Molecular dynamics studies of hematite surfaces with PAM, HPAM and metasilicate
Authors: Quezada Gonzalo R. , Krishna R.S , Mishra Subhabrata , Jeldres Ricardo 
Published: August 2022

Abstract
In the search to improve the obtaining of iron ore, different additives have been proposed to improve this activity. A deeper study is necessary to understand the affinities of different additives on iron ore and thus be able to search for or synthesize new additives according to the desired objective. In this work, the affinities of the iron mineral represented by the hematite crystal on the neutral 001 surfaces at pH ~9 are studied by molecular dynamics methods, in the presence of waters with low salinity and high salinity. The additives to be studied are a sodium metasilicate dispersant, a neutral polyacrylamide (PAM) flocculant, and 25% anionic polyacrylamide (HPAM). The study considered the calculation of the minimum distance between the surface and the additives. The results show that the affinity of the metasilicate is high with the surface. In the case of PAM polymers, their adsorption decreased as the number of salts increased. In the case of HPAM, the adsorption is greater than in PAM and improved with the addition of salts. This indicates that hematite is a surface with a high local charge density that attracts charged groups such as metasilicates and HPAM. the neutral PAM polymer is adsorbed but to a lesser extent due to its neutrality. The presence of salts indicates that there is competition for adsorption on hematite with respect to PAM, but that the salt is beneficial to HPAM due to the formation of cationic bridges. These results will help in the search for additives for the concentration or dispersion of iron ore.
Graphene as a hole transport layer for enhanced performance of P3HT: PCBM bulk heterojunction organic solar cell: a numerical simulation study
Authors: Davis Denet , Shamna M S , Nithya K S , Sudheer K S 
Published: August 2022

AbstractAs sustainable and green energy technologies advance, academic and industrial researchers have been more interested in organic solar cells. Organic solar cells have some key advantages, such as lightweight, flexibility and cheapness that make them an ideal choice as an alternative to other types of solar cells. Bulk heterojunction solar cells combine the advantages of easier fabrication and higher conversion efficiency, making them the best structure currently. In this work P3HT: PCBM is used as the active layer material. PDINO and PFN-Br are used as the electron transport layers in this work. Graphene, which is taken as the hole transport layer in this work, is a unique material for future applications in organic photovoltaics due to its remarkable optical properties and excellent electron/hole transport properties. Corresponding to two different electron transport layers two different device configurations are studied in the work. Bulk hetero-junction organic solar cell simulation study is done using the solar cell capacitance simulator (SCAPS1D). The thickness, electron and hole mobilities, and defect density of the active layer are varied for each device configuration, and their effect on device output performance is analysed. A comparative study of device performance between the different configurations has been done.
Structure and Properties of PBS/PBAT blends and nanocomposites
Authors: Radhakrishnan S. , Thorat S. , Desale Amolkumar , Desai Prachi , Kulkarni M.B. 
Published: August 2022

Abstract
The use of bio-compostable polymers such as Polybutylene Succinate (PBS), Polybutylene Adipate Co-Terephthalate (PBAT) or Polylactic acid is restricted due to the barrier properties especially the water vapor transmission rate (WVTR) which is high in these commercially available polymers. The WVTR plays an important role in preserving the freshness of fruits and vegetables and it has to be optimum. Polymer blending and incorporation of nano fillers are facile routes to formation of internal structure and morphology which gives good control of barrier properties of films. Hence, crystalline structure and morphology of PBS-PBAT blends were studied in detail with respect to composition of the blend. The effect of nanofillers (Halloysite nanotubes/HNT) incorporation as well as addition of polyethylene glycol (PEG) as plasticizer on crystallization process was also investigated. The samples were cast on a glass plate substrate from solution using membrane caster at constant speed and thickness in the range of 100 microns. The composition was varied from 0 to 40 % of PBS in PBAT matrix while addition of HNT was varied from 1 to 5%. Films were air dried in an oven at 50-55 °C for 6 hr. The crystal structure development was studied using wide angle X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and the molecular interaction examined using FTIR. XRD data indicated that PBS crystals were in monoclinic α phase but the relative intensities of the 011 and 020 reflections changed drastically in the blends. The DSC analysis revealed that there was preferential growth of PBS α phase crystals with sharp melting at 110 °C. The HNT gave distinct nucleation effect with a shift in the Tc peak as well as increase of ΔHc value. The preferential nucleation by HNT could be associated with the close lattice match for the HNT and the monoclinic phase of PBS. FTIR studies indicate that the all the contents were dispersed well and show hydrogen bonding interaction at the –OH and –COOH groups. These changes in the crystallinity and crystal phase improved the barrier properties leading to the decrease in (WVTR) with the addition of PBS to PBAT as well as incorporation of HNT in the blend. WVTR decreased from 120 g/m2/day to 55 g/m2/day which is excellent for packaging of green agriculture produce.
Fabrication of Superhydrophobic Surface on Low Carbon Steel
Authors: Satyarathi Jitendra , Kumar Vijay , Kango Saurabh , Sharma Nitin , Verma Rajeev 
Published: August 2022

Abstract
The purpose of the present work is to fabricate superhydrophobic surfaces on commonly used low carbon steel (AISI 1018). Laser surface texturing (LST) method is used for creating circular textures on mild steel surface having the diameter and pitch of 200 μm each. Two different materials (wax & Candle soot) are used to decrease the surface energy of the mild steel. It is observed from the results that the water contact angle of untreated surface increases from 87° to 155° after LST and lowering the surface energy by using wax, followed by candle soot.
Finite Element based Numerical Modelling of Near-Dry EDM with Glycerin-Air Dielectric Mixture
Authors: Jishnu Namboodiri V N , Pazhamannil Ribin Varghese , Govindan P 
Published: August 2022

Abstract
Electrical discharge machining (EDM) is an advanced, non-traditional machining process that is widely employed in sectors such as manufacturing, automotive, aerospace, and medicine. Near-dry EDM is a prospective technology that offers advantages over dry and wet EDM in terms of material removal rate (MRR), tool wear rate (TWR), and surface integrity. A 2D model of the axi-symmetric workpiece based on the Gaussian distribution of the heat flux is used to simulate the single spark in near-dry EDM. The MRR of near-dry EDM is determined at various glycerin flow rates in the glycerin-air combination. The simulation is then performed on the SS304 workpiece with different glycerin flow rates. The results are compared to EDM simulations using N2 and O2 as the dielectric medium. The average MRR of near-dry EDM with an 8 ml/min glycerin flow rate is determined to be 204% higher than that of N2 and 117% higher than that of O2 gas dielectric. When the volumetric ratio of glycerin in the glycerin-air combination increases, the MRR was also found to be increasing. The maximal MRR of near-dry EDM was found to be 129.30703 mm3/min with an 8 ml/min glycerin flow rate and a 0.18 volumetric ratio and a maximal MRR of 144.3407 mm3/min was found with a 15 ml/min glycerin flow rate and a 0.35 volumetric ratio.
Effect of Zn content on microstructure and properties of hypoeutectic and near-eutectic Al-Si alloys
Authors: Dhakar Prashant , Kumar Sandeep , Manani Sunil , Pradhan Ajaya Kumar 
Published: August 2022

Abstract
In this research, the microstructure and mechanical properties of permanent mould cast Al-Si (7 wt.% and 12 wt.%) alloys without and with different amounts of Zn (1 wt.%, 2 wt.% and 4 wt.%) were analysed. The Al-xSi-yZn alloys have been prepared through a stir casting process using an Al-15 wt.% Si master alloy at 800 °C. Optical microscopic analyses have revealed variation in the α-Al matrix and Si needles in the alloy with the variation in Zn content. The mechanical properties analysis has shown that the hardness, tensile strength and wear resistance of the alloys increase with the addition of Si but decrease with the addition of Zn, within the limit of the alloying additions of the present research.
Effect of Boronizing on the High Temperature Mechanical Behavior of Inconel 625
Authors: Bilgin Onur , Yapici Guney Guven 
Published: August 2022

Abstract
Inconel 625 is a frequently used material specifically in the exhaust and piping components of gas turbine engines, because of its good corrosion resistance even at high temperatures. In this work, the effect of boronizing on the room and high temperature tensile behavior of Inconel 625 alloy was investigated. According to the room temperature tensile test results, yield strength (YS) and ultimate tensile strength (UTS) of the samples reduced after boronizing. This strength reduction may be attributed to the softening of the material throughout the boronizing process at a high temperature of 1100°C. On the other hand, ductility of the Inconel 625 samples decreased. At elevated temperature, the yield strength of the boronized sample significantly reduced because of the possible decomposition of boron particles throughout tensile straining at elevated temperatures. Consequently, the fracture morphology observations revealed that the main fracture mechanism of both coated and uncoated conditions at high temperature was ductile fracture represented by coarse and deep dimples.
Spin dependent Electronic properties of NO-adsorbed zigzag ZnO nanoribbons: A DFT Study
Authors: Kumar Ravindra , Rakesh Ajay Kumar , Govindan Anil , Jaiswal Neeraj K. 
Published: August 2022

Abstract
Exploring novel nano-materials for designing the robust and efficient sensors is an area of immense potential. In the present work, we study the adsorption of NO molecules at the edges of zigzag ZnO nanoribbons (zZnONR). The adsorption of NO molecules was modelled at the edges of zZnONR in different possibilities. It is well known that pristine (H-passivated) zZnONR is a semi-conducting material. Present calculations reveal that NO-adsorption takes place via N-side and a semiconductor to metallic-transition is also witnessed in all configurations. The obtained adsorption energies are found to vary between -4.10 eV to -7.04 eV ensuring the exothermic nature of the adsorption process and energetic feasibility of the considered configurations. Interestingly, all the considered structures (with NO adsorption) prefer magnetic ground state in contrast to previously reported non-magnetic behaviour of pristine zZnONR. Furthermore, NO adsorption at both the edges makes the structure half-metallic. In contrast, rest of the two-configurations are pure metallic. Present findings indicate that zZnONR could play a vital role towards NO detection as well realizing the spintronic properties for other various other technological applications.
Electrochemical corrosion performance of eutectic Al-Si automotive alloy in 0.1 M and 0.2 M NaCl solution
Authors: Khan Akib Abdullah , Kaiser Mohammad Salim 
Published: August 2022

AbstractCorrosion behavior of eutectic Al-Si automotive alloy is investigated in different strengths of 0.1 M and 0.2 M NaCl solution at room temperature. Alloy with Si as trace impurity is also considered for the comparison of the property. The study is done by electrochemical method, using potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS) techniques. The alloy surfaces are characterized by both optical microscopy and scanning electron microscopy. The results indicate that Si addition improves the corrosion performance of the Al-Si automotive alloy and this improvement is more pronounced in higher corrosive environments. The corrosion rate along with current density (Icorr) of trace Si added alloy showed higher value than that of higher Si added alloy. The corrosion potential (Ecorr) and open circuit potential (OCP) of higher Si added alloy are shifted to the more noble direction. The cause behind this, the higher amount of Mg2Si precipitates in higher Si added alloys tends to form oxides like SiO2 and MgO which protects the surfaces from further corrosion. Microscopic images confirm that the polishing scratches on the surfaces of the alloys are not visible after corrosion. The SEM images also confirm that the corroded surfaces seem to have pit formations which are lower in higher Si added alloys due to formation of a protective layer of oxides. The higher corrosion performance is observed for higher Si added alloys especially in higher strength of corrosive environment.
Natural Frequency Evaluation of Low-Pressure Stage Blade of a 210 MW Steam Turbine
Authors: Rani Pooja , Agrawal Atul Kumar 
Published: August 2022

Abstract
Steam turbines rely heavily on the performance and reliability of their rotor blades. When a steam turbine blade fails, it can pose a risk to workers' life, need expensive repairs, and cause income losses. The failure mechanism differs from case to case and is typically quite complex. The last stage turbine blades are very long and rotate at high speed. In extreme dynamic loads, these big blades are the most susceptible to failure. So, the dynamic behaviour of the last stage steam turbine blade is of great importance and analysed by numerical simulation in this work. Mode shapes at natural frequencies of the blade at stationary condition and at different speeds of rotation are determined. A Campbell diagram is used to forecast the expected operational conditions that may result in blade resonant vibration.
Temperature Analysis of Friction Stir Welding (AA6061-T6) with Coupled Eulerian-Lagrangian Approach.
Authors: Chalurkar Chetan , Shukla Dinesh Kumar 
Published: August 2022

Abstract
For Friction Stir Welding (FSW), several simplified FEM models have been developed to explain key parts of thermal-mechanical phenomena. In this study, to simulate the FSW process of the AA6061-T6 aluminum alloy, a thermo-mechanical 3-D finite element model based on the Coupled Eulerian-Lagrangian (CEL) approach is used. The CEL method combines the benefits of both the Lagrangian and Eulerian approaches, allowing it to solve large-scale deformation issues. The Abaqus/CAE software is used to simulate the stages of the FSW process using the Johnson–Cook material law and the Johnson-Cook failure model. The CEL approach is used to estimate process parameters based on the model's boundary conditions of the 3-D rigid tool. Thermocouples were installed in the appropriate positions on the AA6061-T6 plate, and temperature is correlated with the simulation results. The temperature generated during the plunging, dwelling, and welding stages of the FSW of AA6061-T6 is 80% to 90% of the melting temperature being evaluated. The experimental data was obtained from the HMT made CNC (Siemens) operated VMC and the same is compared with the results obtained from the overall FEM simulation.
Analysis on the Suitability of Powder Metallurgy Technique for Making Nickel Based Superalloys
Authors: Salwan Geetika Kumari , Subbarao Rayapati , Mondal Subrata 
Published: August 2022

Abstract
Nickel based superalloys are of a typical class of materials with an exceptional capability of retaining strength and toughness at high temperatures. Also, they have high resistance to degradation in corrosive environments. These properties of superalloys make them ideal materials for gas turbine engines used in power generation, marine engineering and aircraft applications. Earlier, researchers studied about the suitability of cast and wrought superalloys for their applicability in gas turbines. Superalloys are developed from polycrystalline to directionally solidified alloys and finally single crystal alloys by investment casting process for making turbine blade. In this work, the powder metallurgy technique is analysed for determining its appropriateness for making nickel based superalloys in gas turbines. This technique includes powder blending, compaction and sintering with or without post heat treatment for making a product. This process can offer high performance applications, where unique microstructural and mechanical characteristics are required. Refractory material can be easily alloyed by this technique, to enhance heat bearing capabilities. In this work, the development of nickel based superalloys by powder metallurgy technique, their composition as well as the influence of various elements on mechanical properties is analysed. Major defects like prior particle boundary (PPB) precipitation, thermally induced porosity (TIP), and non-metallic inclusion have to be taken care, in order to see that the mechanical properties are not deteriorated. It is observed that alloys like IN100, Rene95, and N18, Rene 88DT, ME3 and R1000 developed by powder metallurgy technique have sufficient temperature bearing capability for 1000 hr service life at 630 MPa. Alloys like U720 Li, IN 718 plus and U 720, made by casting technique and alloys like ME3, IN 100, and U720, made by powder metallurgy technique are compared on the basis of stress and temperature bearing capability. It is found that ME3 alloy prepared by powder metallurgy technique is the efficient nickel based superalloy with maximum heat bearing capability.