Search Results (192)

Flying wing Unmanned Aerial Vehicles (UAVs) are an interesting flight configuration, considering its benefits over aerodynamic, structural and added stealth aspects. The existing configurations are thoroughly studied from the literature survey and useful observations with respect to design and analysis are obtained. The proposed design method includes distinct calculations of the UAV and modelling using 3D experience. The created innovative models are simulated with the help of computational fluid dynamics techniques in ANSYS Fluent to obtain the aerodynamic parameters such as forces, pressure and velocity. The optimization process continues to add more desired modifications to the model, to finalize the best design of flying wing frame for the chosen application and mission profile. In total, nine models are developed starting with the base model, then leading to the conventional, advanced and nature inspired configurations such as the falcon and dragonfly models, as it has an added advantage of producing high maneuverability and lift. Following this, fluid structure interaction analysis has been performed for the best performing configurations, resulting in the determination of variations in the structural behavior with the imposition of advanced composite materials, namely, boron, Kevlar, glass and carbon fiber-reinforced polymers. In addition to this, a hybrid material is designed by combining two composites that resulted in superior material performance when imposed. Control dynamic study is performed for the maneuvers planned as per mission profile, to ensure stability during flight. All the resulting parameters obtained are compared with one another to choose the best frame of the flying wing body, along with the optimum material to be utilized for future analysis and development. Full article

This study investigates the photocatalytic degradation of methylene blue (MB) using strontium-doped SnO₂ nanofibers synthesized via electrospinning. The 1% Sr-doped SnO₂ nanofibers exhibited remarkable photocatalytic activity, achieving 84.74% MB degradation under visible light irradiation, substantially outperforming both undoped SnO₂ nanofibers (61%) and the same catalyst under UV light (69%) under identical experimental conditions. Comprehensive electrochemical investigations revealed that Sr doping fundamentally transformed interfacial charge transfer kinetics, with 1% Sr-doped nanofibers exhibiting a remarkable three-fold decrease in charge transfer resistance (404 Ω compared to 1350 Ω for undoped samples), a dramatic enhancement in charge carrier density (5.17 × 10²² versus 9.24 × 10¹⁹ for undoped samples), and an approximately eight-fold increase in diffusion coefficient (8.78 × 10⁻¹⁰ versus 1.13 × 10⁻¹⁰ cm²s⁻¹). These electrochemical improvements were corroborated by comprehensive structural characterization, which demonstrated that strategic Sr incorporation induced beneficial oxygen vacancies, reduced crystallite size, increased microstrain, and enhanced dislocation density, collectively contributing to superior surface reactivity and accelerated photocatalytic mechanisms. This work establishes a quantitative correlation between electrochemical characteristics and photocatalytic activity in Sr-doped SnO₂ nanofibers, revealing the fundamental mechanisms that transform the SnO₂ nanostructure from UV-dependent to efficient visible light-driven catalysts for organic pollutant degradation. Full article

Humanity faces significant challenges in achieving internationally agreed sustainable development goals, particularly in reducing public health risks and improving the environmental quality. Measuring and comparing performance across regions requires a systematic and transparent framework. This study explores the application of sustainable development indicators, including a mortality rate attributed to exposure to unsafe WASH services (SDG 3.9.2), a mortality rate attributed to household and ambient air pollution (SDG 3.9.1), and a mortality rate attributed to unintentional poisoning to assess regional health outcomes. Using data from 50 countries across five sub-regions of Asia, this research applies a weighted neutrosophic similarity measure based on the Hausdorff metric to evaluate regional alignment with an ideal benchmark. The results reveal significant disparities across regions, highlighting Central Asia as the closest to the benchmark, while South and West Asia exhibit substantial gaps. These findings provide actionable insights for policymakers to improve public health infrastructure and address environmental challenges, promoting equitable and sustainable development. Full article

Silicon-on-Insulator (SOI) technology and optical resonators have significantly influenced the field of photonics for malignancy sensing. Cancer, a malignant disease, necessitates the precise and advanced diagnostic technique. This study introduces a novel approach for cancer detection utilizing a micro racetrack ring resonator (MRTRR) integrated with Subwavelength Gratings (SWGs). The grating pitch size (Λ) is 300 nm. The findings demonstrate that the SWG MRTRR achieves high Sensitivity (S) due to enhanced light matter interaction and weak mode confinement. The SWG MRTRR produces a spectral envelope as the transmission output, which eliminates the limitation of free spectral range (FSR). The ‘S’ values obtained for cervical cancer, breast cancer type-1, and breast cancer type-2 are 1825 nm/RIU, 1705.14 nm/RIU, and 1004.71 nm/RIU. The Q-factor and the intrinsic Limit of Detection (iLoD) values are 269.68, 280.78, 315.76, 3.28 × 10⁻³, 3.37 × 10⁻³, and 5.09 × 10⁻³, respectively. Full article

This study presents a topological design and modeling framework for 3D-printed robotic grippers, tailored for combined precision and coarse robotics assembly. The proposed methodology leverages topology optimization to develop multi-scale-compliant mechanisms, comprising a symmetrical continuum structure of five beams. The proposed methodology centers on the hybrid kinematics for precision and coarse operations of the gripper, parametrizing beam deformations in response to a defined set of boundary conditions and varying input loads. The research employs topology analysis to draw a clear correlation between input load and resultant motion, with a particular emphasis on the mechanism’s capacity to integrate both fine and coarse movements efficiently. Additionally, the paper pioneers an innovative solution to the ubiquitous point-contact problem encountered in grasping, intricately weaving it with the stiffness matrix. The overarching aim remains to provide a streamlined design methodology, optimized for manufacturability, by harnessing the capabilities of contemporary 3D fabrication techniques. This multifaceted approach, underpinned by the multiscale grasping method, promises to significantly advance the domain of robotic gripping and manipulation across applications such as micro-assembly, biomedical manipulation, and industrial robotics. Full article

In the present study, exopolysaccharides (EPS-1, EPS-2, and EPS-3) were extracted from Lactobacillus graminis, and their chemical compositions, bioactivities, and cytotoxicity were comprehensively studied. A higher yield was observed for EPS-1 and EPS-2 with 14.38% and 9.24%, respectively. The chemical composition in the samples was studied using FT-IR analysis. The EPS-1 (1 mg/mL) showed higher antioxidant activities with 34.5 ± 6.6% and 93.6 ± 2.3% of DPPH and ABTS radical scavenging, respectively. In the cellular antioxidant assay, the EPS-1 protected oxidative stress-mediated cellular damage in AAPH-treated NIH3T3 cells. In addition, EPS-1 (0.25 mg/mL) treatment augmented the viability of AAPH-stressed RAW264.7 cells (~80%) than AAPH-treated cells (~50%) by reducing the ROS level and associated oxidative damage. Toxicity studies indicated that EPS-1 (1 mg/mL) did not induce notable cytotoxic effects in NIH3T3 cells, RAW264.7 cells, and erythrocytes. Altogether, the findings of this research suggest that L. graminis could be a source of biocompatible polysaccharides with antioxidant properties. Full article

High-chromium white iron (HCWI) alloys are often used in industries such as mining which require a high wear resistance. Whilst nitrogen is known as a good austenitic stabiliser, the effects of nitrogen on corrosion properties for welded HCWI have not been studied. Chromium hardfacing alloys were deposited via gas metal arc welding using nitrogen as a shielding gas at flow rates of 5 L/min, 10 L/min, and 15 L/min. The corrosion behaviour of these modified alloys was studied using electrochemical techniques such as potentiodynamic measurements and electrochemical impedance spectroscopy. Higher gas flow rates were found to increase the volume fraction of the eutectic austenite while reducing the amounts of eutectic carbides. Nitrogen did not transform the M₇C₃ (M = Cr, Fe) carbides into any other form of carbides. The sample without nitrogen as a shielding gas was found to display the worst corrosion resistance after electrochemical testing, such as corrosion resistance parameters in EIS tests. Higher nitrogen shielding gas flow rates were found to produce higher levels of corrosion resistance; this was especially true for the 15 L/min sample with a corrosion resistance parameter to EIS that was more than double that of the sample without nitrogen shielding gas (e.g., 4700 vs. 2325 Ω·cm² respectively). Full article

A wide variety of endogenous and exogenous alkylating agents covalently modify DNA to produce N7-alkyl-2′-deoxyguanosine (N7-alkylG) adducts as major DNA lesions. The mutagenic potentials of many N7-alkylG adducts with an intercalatable moiety remain poorly understood. We have discovered that the antiriot agent 2-chloroacetophenone readily reacts with dG to produce N7-acetophenone-dG adducts, implicating the genotoxic properties of 2-chloroacetophenone. 2-Chloroacetophenone, however, has been found to be nonmutagenic in both bacterial and mammalian cells. To gain insights into the nonmutagenic nature of N7-acetophenone-dG, we prepared N7-acetophenone-dG-containing oligonucleotide via 2′-fluorine-mediated transition-state destabilization and conducted kinetic and structural studies of human DNA polymerase eta (polη) incorporating nucleotide opposite 2′-F-N7-acetophenone-dG. The kinetic experiments reveal that the presence of the lesion at the templating position greatly hinders nucleotide incorporation. A crystal structure of polη bound to a nonhydrolyzable dCTP analog opposite 2′-F-N7-acetophenone-dG shows that the templating N7-acetophenone-dG is in a syn conformation, precluding binding of an incoming nucleotide in the catalytic site. These unusual conformations explain the observed inefficient incorporation of nucleotide opposite the lesion. Our studies suggest that certain bulky N7-alkylG lesions adopt a syn conformer and present an intercalatable moiety into the nascent base-pairing site, deterring nucleotide incorporation and thus lowering mutagenicity. Full article

The need for safe and healthy air quality has become critical as urbanization and industrialization increase, leading to health risks and environmental concerns. Gas leaks, particularly of gases like carbon monoxide, methane, and liquefied petroleum gas (LPG), pose significant dangers due to their flammability and toxicity. LPG, widely used in residential and industrial settings, is especially hazardous because it is colorless, odorless, and highly flammable, making undetected leaks an explosion risk. To mitigate these dangers, modern gas detection systems employ sensors, microcontrollers, and real-time monitoring to quickly identify dangerous gas levels. This study introduces an IoT-based system designed for comprehensive environmental monitoring, with a focus on detecting LPG and butane leaks. Using sensors like the MQ6 for gas detection, MQ135 for air quality, and DHT11 for temperature and humidity, the system, managed by an Arduino Mega, collects data and sends these to the ThingSpeak platform for analysis and visualization. In cases of elevated gas levels, it triggers an alarm and notifies the user through IFTTT. Additionally, the system includes a microphone and a CNN model for analyzing audio data, enabling a thorough environmental assessment by identifying specific sounds related to ongoing activities, reaching an accuracy of 96%. Full article

Papaya (Carica papaya L.) is a highly nutritious fruit crop cultivated commercially in the tropical and subtropical regions of the world. Being a shallow rooted fruit crop, it requires frequent application of nutrients. Papaya is highly remunerative due to its high productivity and responds positively to nutrient application. Papaya Ring Spot Virus (PRSV) is a major threat to papaya production, which causes severe yield loss and reduces fruit quality. To combat PRSV and enhance productivity, a nutrient formulation was developed by combining organic, inorganic nutrient sources with biocontrol agents to improve the health and vigor of the plants. Experiments were conducted to standardize the application time and evaluate the efficacy of nutrient formulation in enhancing yield, and to combat papaya ring spot virus (PRSV) incidence in papaya from January 2021 to December 2023 at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India. The results revealed that foliar application of nutrient formulation at monthly intervals from the 3rd to the 7th month after planting (MAP) along with regular application of recommended dose of fertilizers (RDF) at bimonthly intervals from the 3rd MAP significantly increased the yield (37.79% and 30.57% in TNAU Papaya CO 8 and Red Lady, respectively) and reduced PRSV disease incidence (22.49% in TNAU Papaya CO 8 and 16.53% in Red Lady). Metabolomics study indicates that foliar spray of nutrient formulation enhanced the activators and precursors of defense enzymes, viz., peroxidase (PO), polyphenol oxidase (PPO), phenyl ammonia lyase (PAL), catalase (CAT) and nitrate reductase (NRase) in the sprayed plants over unsprayed control. Therefore, the sprayed plants exhibited tolerance to PRSV incidence by maintaining vigor and induced systemic resistance by the defense enzymes. Full article

This research study aims to study and investigate the corrosion rate, hot tensile properties, and microstructures of SSDS 2507 and AISI 316 gas tungsten arc dissimilar weldments. Three separate samples were developed with frequencies of 2, 4, and 6 Hz using the pulse arc mode technique. The tensile characteristics were assessed at two distinct temperatures (27 °C and 350 °C) in order to examine the behavior of the welded structure. Mechanical characterization such as hardness measurement and corrosion behavior were studied. The metallurgical characteristics of pulsed and continuous current weldments were examined using microscopes (optical and scanning), revealing variations across different zones. At the 4 Hz pulse frequency, the material exhibited improved tensile qualities compared to constant arc welding. The microstructures indicated that the fusion zone in the pulsed arc weldment consisted of a balanced mixture of inter-granular austenite and ferrite phases. A better corrosion resistance rate of 0.0487 mm/year was observed in the pulsed arc weldment compared to both the SSDS2507 base metal and the constant arc weldment. Specifically, at a temperature of 27 °C, the ultimate tensile strength was 695 MPa, whereas at a temperature of 350 °C, the tensile strength was 475 MPa. The weld strength of the pulsed arc weldment exhibited a 15.8% improvement in comparison to the constant arc weldment. The surface hardness value increased to 240 HV compared to the constant arc weldment, which had an HV of 225. Full article

Mass vaccination against peste des petits ruminants (PPR) in two southern states of India, namely Andhra Pradesh and Karnataka, has reduced disease outbreaks significantly. The sporadic outbreaks reported now can be attributed in part to the recurring movement of sheep and goats between these contiguous states. This study assessed the present level of economic burden and impact of vaccination on the local system (one state), considering the exposure from the external system (neighboring state) using a system dynamic (SD) model. The SD model relies on interdependence, interaction, information feedback, and circular causality and captures potential feedback between disease control interventions and their impact on various epidemiological and economic outcomes. The data for parameterization of the model were collected through surveys, expert elicitation, and literature review. The sporadic outbreaks reported in recent years (<10 outbreaks/year during 2022) were due to continuous “mass vaccination” for more than a decade. During 2021–2022, the PPR incidence was less in both the states, with an estimated loss of USD 26.30 and USD 22.86 million in Andhra Pradesh and Karnataka, respectively. The SD model results showed a systemic increase in flock size and offtakes and a decline in the number of infected and death cases under high vaccination coverage (75% and 100% coverage) compared to the low-coverage scenario. Hence, the coordinated inter-state vaccination efforts offer better prospects, as efforts in one state have positive externalities in terms of fewer outbreaks in a neighboring state. Full article

The effects of heat treatment on the microstructure and corrosion behavior of chromium carbide-based hardfacing alloys deposited via gas metal arc welding were investigated. The hardfacing alloy, high chromium white iron (HCWI), containing 27 wt% Cr and 4.8 wt% C, was heat treated at 650 °C and 950 °C for six hours followed by natural cooling to room temperature. Microstructural characterization revealed that heat treatment promoted the transformation of austenite to ferrite and increased carbide precipitation. X-ray diffraction analysis identified the primary carbides as Cr₇C₃, which remained stable during heat treatment. Electrochemical corrosion testing in artificial seawater, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), demonstrated progressively improved corrosion resistance with heat treatment temperature. Both techniques confirmed that the specimen treated at 950 °C exhibited superior corrosion resistance compared to the 650 °C treatment and as-deposited condition, with the specimen treated at 950 °C exhibiting the highest charge transfer resistance (4711 Ω·cm²) compared to the 650 °C treatment (2608 Ω·cm²) and as-deposited condition (374.6 Ω·cm²). The enhanced corrosion resistance was attributed to the increased carbide precipitation and optimization of the matrix composition. While heat treatment at both temperatures improved corrosion performance, the 950 °C treatment yielded superior results, suggesting this could be an optimal temperature for enhancing the corrosion resistance of chromium carbide-based hardfacing alloys. Full article

The advent of flying taxis, also known as vertical take-off and landing (VTOL) aircraft, presents a revolutionary approach to urban transportation by offering faster, more flexible, and less congested travel options. This research aims to explore the potential impact of flying taxis on urban transportation systems, focusing on their implementation, regulation, and benefits across various industries. This study investigates the role of government in monitoring and regulating flying taxis to ensure safety and compliance with regulations, addressing key considerations such as licensing, air traffic control, safety standards, insurance requirements, and privacy concerns. Through a comprehensive review of the existing literature and case studies, this paper presents the advantages of flying taxis, including time savings, accessibility to remote areas, reduced traffic congestion, and enhanced travel experiences. Additionally, the economic benefits of manufacturing flying taxis, such as job creation and technological advancements, are discussed. The findings suggest that flying taxis have significant potential to transform urban transportation, but their adoption requires collaboration among stakeholders, robust regulatory frameworks, and substantial infrastructure investments. The conclusions highlight the practical application value of flying taxis in promoting sustainable urban mobility and driving innovation in transportation. Full article