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Tetrahydrofuran (THF) hydrate is a useful material for cold storage applications and an excellent substitute for simulating natural gas hydrates. THF also serves as a thermodynamic promoter for hydrate formation. The selection of suitable THF concentration in the aqueous solution remains a challenging task for the utilization of the THF hydrate. Present work focuses on the influence of non-stoichiometric solutions on THF hydrate growth. The THF hydrate was grown in polycrystalline form as a gross hydrate layer from the wall towards the center of a cylindrical reactor. Experiments were conducted at the three THF concentrations 19.06, 30, and 15 wt% at 276.15 K and atmospheric pressure. Transient imaging of the hydrate provided the hydrate thickness with time. Moreover, the chemical affinity model was used to analyze the hydrate formation kinetics. An increase in the concentration of the THF in bulk solution accelerated hydrate growth with time. We found that non-homogeneity in the THF hydrate front increased in the azimuthal direction if the concentration of THF in the THF-water solution deviated from stoichiometric concentration. A hypothesis was also proposed to explain the above observation. The non-homogeneity was qualitatively shown by binary images and mathematically quantified using the maximum to minimum hydrate thickness ratio. The chemical affinity model proved effective in describing hydrate growth kinetics.

This paper studies the buckling behavior of T-shaped composite stiffened panels reinforced by both straight and curvilinear sub-stiffening configurations subjected to compression. First, the simulated buckling response of the T-shaped stiffened composite panel is verified with experimental results from the existing literature. Subsequently, straight and curvilinear I-shaped sub-stiffeners are introduced into the design of the T-shaped stiffened composite panel. The distribution and laminate stacking sequence of straight and curvilinear sub-stiffened composite panels are optimized to improve buckling performance while maintaining a constant weight constraint. Further, a parametric analysis was implemented to assess the influence of the sub-stiffener curvature on the buckling response of the curvilinear grid sub-stiffened composite panel. Results demonstrate that introducing straight and curvilinear grid sub-stiffeners into the T-shaped stiffened composite panel improves buckling performance. Specifically, the introduction of straight sub-stiffeners results in a remarkable improvement of up to 200% in buckling performance, while introducing curvilinear grid sub-stiffeners exhibits an even more noteworthy improvement of up to 260%, which shows the superior design of curvilinear grid sub-stiffeners when compared to straight sub-stiffeners. This investigation delivers valuable insights into the design of sub-stiffened composite panels for improving structural performance, offering significant advantages for industries such as aerospace that require lightweight structures yet are resistant to buckling.

Topic classification is a challenging task in order to comprehend the subject matter or theme of the Indian mythology. It will enhance the performance of NLP-based systems, such as recommendation and semantic search engines, when dealing with texts containing mythology. This research focuses on developing transformer based models for automated topic classification of Indian mythological documents, which addresses the challenges of organizing and analyzing this rich and diverse corpus. We introduce PouranicTopic, a new annotated dataset containing over 200k verses from 7 major Hindu texts with canto, topic, and sentence labels. Additional datasets Similarity-based and Log-likelihood-based are created using sentence clustering techniques. The BERT, RoBERTa, and DistilBERT models are evaluated for canto and topic classification on these datasets. Clustering greatly improves the results on the Similarity-based dataset, but Log-likelihood-based dataset remains challenging.

The investigation describes the processing and analysis of laser welded Hastelloy-X (HX) alloy joints through this paper. HX alloys are employed in aerospace and nuclear industries, especially for high-temperature applications. In this research, a series of laser beam welding (LBW) experiments denoted as E1 to E9 were conducted on the HX base metal (BM), adhering to the L9-orthogonal array (L9-OA) design matrix. CO₂ laser technology was employed to fabricate HX butt joints. The laser power, focal length and welding speed were the variables. Then, the character of each joint was analyzed by sophisticated testing methods as per ASTM standards. The results showed that the character of each sample was varied depending on the selection of parameters. The E5 sample had a maximum tensile strength (TS) and ductility with 93 % joint efficiency. The grain elongation and refinement in the weld zone (WZ) were confirmed through microstructures and electron back scattered diffraction (EBSD) studies. The corrosion character of each joint (E1 to E9) was analyzed using the potentiostatic polarization method. The E1 sample had the highest corrosion resistance. The corrosion rate was in the range of 7.4E−03 to 8.6E−05 mm/yr. The dry sliding wear test (A1 to A9) was carried out as per L9-OA on the E1 sample, since this weld parameter had good corrosion resistance, by varying applied load, sliding distances and sliding velocities. Wear test results showed an increase in wear rate with the increase in load and sliding distance. A wear map was also drawn using the results to find out the association between wear rates and wear parameters. Weld speed had influenced the strength of the joint and laser power had shown an impact on the corrosion and wear of the HX alloy joints. The weld zone, corroded sample and the worn-out surfaces of weld joints were further analyzed using an optical microscope (OM) and Field Emission Scanning Electron Microscopy (FESEM).

A remotely-controlled wetland paddy seeder (RCWPS) with a mechatronic seed-metering device was developed for precise sowing of pre-germinated paddy seeds in wet puddled field. The RCWPS, powered by a 180 W DC motor, utilized two lugged wheels for propulsion. Linear actuator-controlled dog clutch was connected with each wheel to discontinue the power supply while turning. The four-row seed metering unit comprised a seed metering plate with holes at 200 mm spacing, actuated by a solenoid. The diameter of the metering plate hole, operating speed, and speed of agitation were maintained at 11.18 mm, 0.84 km h⁻¹, and 37 rpm, respectively. This comparative study assessed its performance and operational costs at 1/3^rd and 2/3^rd seed filling levels under puddled conditions, comparing it to a conventional drum seeder. At 2/3^rd seed filling, RCWPS demonstrated 96% feed index quality, no multiple index, 4% missing index, 85.46% hill-distribution uniformity coefficient, and 72.45% seed dropping uniformity coefficient. Meanwhile, the values observed for drum seeder were 78.33%, 6.67%, 15%, 69.85%, and 60.94%, respectively. Similar results were observed at 1/3rd filling level. It showed better quality seed-dropping with RCWPS compared to the conventional drum seeder at all degrees of seed filling. The total cost for seeding per hectare of land with RCWPS and drum seeder were found to be 28.05 USD and 12.77 USD, respectively and the break-even point were found 0.54 ha year⁻¹ and 0.038 ha year⁻¹, respectively.

Non-Newtonian behaviour of the Magnetorheological (MR) fluid under the influence of external magnetic field can be commissioned to design various applications such as MR brake, damper, and clutches, etc. Better design strategies, material selection and characterization led to realize the potential of MR brakes to replace conventional brakes. The present study emphasises on developing lightweight (1.8 kg) multi-rotor MR brake (MMRB). Finite element method magnetics (FEMM) software is utilized to determine the material required for a single-rotor MRB. FEMM material selection analysis is incorporated into the modeled MMRB, and the nature of magnetic flux density throughout the MR gap was obtained. Magnetic circuit analysis of the proposed brake is carried out to find torque estimation using analytical equations and Bingham plastic model. The proposed brake is fabricated and characterized using commercial MRF (132 DG, Lord Corporation). The study compares the torque outputs obtained experimentally with finite element analysis (FEA) and analytical approach. The average maximum magnetic flux density through FE analysis is found to be 0.45 T @ 3 A current. The average error between FE obtained and experimentally obtained torque output of the brake is around 5%. Further, an alternate design is proposed by utilizing same rotor diameter and number of electromagnetic coils. The new design is lighter in weight (0.8 kg) and exhibits enhancement in the torque output and torque to weight ratio by around 31% and 55%, respectively than the present design.

An event-triggered-super twisting sliding mode control (ET-STSMC) with saturation function in reaching law have been designed for a nonlinear Quadcopter model with bounded disturbance and its performance is compared with Event Triggered-Sliding mode control (ET-SMC). Simulation results have been obtained for altitude and attitude tracking, demonstrating the stability of the closed-loop system with the proposed control. The event-triggering conditions are derived based on the Lyapunov method, ensuring non-accumulation of inter-event execution time. Experiments have been performed in real-time to analyse the robustness and computational cost in terms of the number of control updates of the proposed control strategy under normal flight, external disturbances, and parameter uncertainty. Simulation and experimental results show that ET-STSMC can achieves better tracking performance and robustness with reduced computational cost compared to ET-SMC during all flight conditions.

The geometries constructed using the standard CAD software are always boundary-represented (B-Rep). Due to this, analysis-suitable volumetric parameterization of the geometries constructed using the standard CAD software is necessary for three-dimensional isogeometric analysis (IGA). This paper presents a user-friendly, robust volumetric parametrization tool capable of processing the B-Rep of the geometries constructed in one of the most popular CAD software, i.e. Rhinoceros^®. The developed tool traverses multiple stages, starting with reading the standard 3DM CAD files of an arbitrarily shaped geometry. It then extracts surface control points, organizes them to establish an outer structural framework, and employs Coons volume parameterization to generate internal control points based on user-defined specifications. We use the NURBS-Python library for reading 3DM files and the NURBS toolbox to visualize and evaluate NURBS functions in the constructed geometries. We construct several baseline and intricate shape geometries to showcase the robustness and generality of the developed tool. Additionally, to demonstrate the effectiveness and applicability of our tool for IGA of non-linear three-dimensional problems, we simulate frictionless contact between two deformable geometries constructed using the developed tool.

This study examined the electrophoretic deposition (EPD) of titanium nitride (TiN) on AISI D2 tool steel, analyzing coating properties and TiN nanoparticle stability in the presence of polyethyleneimine as a dispersant in isopropyl alcohol. The parameters investigated were deposition time (5, 10, and 15 minutes), electric field strength (0.2, 0.5, 1, 1.5, and 2 V/m), and suspension concentration (0.2, 0.3, and 0.4 mg/L). Results indicated that a deposition time of 10 minutes with an electric field strength of 0.5 V/m and a suspension concentration of 0.2 mg/L provided optimal results in terms of thickness and micro-hardness. Higher deposition time led to increased thickness but decreased micro-hardness, while increasing electric field intensity for a constant deposition time led to increased deposition mass and thickness but lower quality at higher concentrations. Microstructural examination and micro-hardness testing confirmed these findings.

Coronary arteries serve a crucial purpose in the circulatory system as they supply blood to the human heart, a highly oxidative organ. As the blood flows through these arteries, the constituents of blood such as proteins and fatty acid molecules may start depositing on the arterial lining. These depositions narrow down the arteries and obstruct the blood flow to the heart. This phenomenon is termed as atherosclerosis, responsible for coronary artery disease, a leading cause of death globally. The progression of disease is affected by coronary hemodynamics which strongly depends on the geometrical complexities such as branching and tapering, and the associated parameters such as curvature and tortuosity. These geometrical parameters vary across the population and are affected by factors such as dietary habits, gender, lifestyle and genetics. Technological advancements in the past few decades have resulted in emergence of patient-specific computational fluid dynamics (CFD) modelling as an important tool in cardiovascular engineering and technology. Patient-specific CFD modelling utilises the clinically obtained patient-specific geometrical and boundary condition data to model the flow and gain an insight in the detailed hemodynamic behaviour, calculate different parameters which can be used as biomarkers and assess different treatment options. In this article, we provide a brief overview of the human coronary circulation and typical steps involved in patient-specific modelling. Further, the studies on patient-specific coronary hemodynamics are extensively reviewed and a perspective on future trends is provided. We believe that the article will serve as a beginner’s guide for the researchers working in this emerging area.

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