16168 research outputs found
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A framework for autonomous UAV navigation based on monocular depth estimation /
No full textUAVs are vastly used in practical applications such as reconnaissance and search and rescue or other missions which typically require experienced operators. Autonomous drone navigation could aid in situations where the environment is unknown, GPS or radio signals are unavailable, and there are no existing 3D models to preplan a trajectory. Traditional navigation methods employ multiple sensors: LiDAR, sonar, inertial measurement units (IMUs), and cameras. This increases the weight and cost of such drones. This work focuses on autonomous drone navigation from point A to point B using visual information obtained from a monocular camera in a simulator. The solution utilizes a depth image estimation model to create an occupancy grid map of the surrounding area and uses an A* path planning algorithm to find optimal paths to end goals while navigating around the obstacles. The simulation is conducted using AirSim in Unreal Engine. With this work, we propose a framework and scenarios in three different open-source virtual environments, varying in complexity, to test and compare autonomous UAV navigation methods based on vision. In this study, fine-tuned models using synthetic RGB and depth image data were used for each environment, demonstrating a noticeable improvement in depth estimation accuracy, with reductions in Mean Absolute Percentage Error (MAPE) from 120.45% to 33.41% in AirSimNH, from 70.09% to 8.04% in Blocks, and from 121.94% to 32.86% in MSBuild2018. While the proposed UAV autonomous navigation framework utilizing depth images directly from AirSim achieves 38.89%, 87.78%, and 13.33% success rates of reaching goals in AirSimNH, Blocks, and MSBuild2018 environments, respectively, the method with pre-trained depth estimation models fails to reach any end points of the scenarios. The fine-tuned depth estimation models enhance performance, increasing the number of reached goals by 3.33% for AirSimNH and 72.22% for Blocks. These findings highlight the benefits of adapting vision-based models to specific environments, improving UAV autonomy in visually guided navigation tasks
Calculating the environmental impact reduction due to extended lifespan of clothing through clothing swaps /
No full textThis paper presents an algorithm for evaluating the environmental impact of clothing swaps, promoting extended use and responsible consumption. Implemented in an online swapping platform, the algorithm quantifies reductions in environmental impact due to extended clothing lifespan and avoided purchase of new garment, promoting swapping activities. Developed through scientific literature analysis, Life Cycle Assessment (LCA), and swapping practice studies, the algorithm uses key environmental indicators: carbon footprint, water use, energy consumption, and land use. It integrates consumer behaviour insights and uses both default and user-entered clothing data to calculate environmental savings. Results show that clothing impact varies by fabric. Viscose and polyester garments have the lowest environmental impact, while swapping cotton and wool items yields the highest savings, as these materials are more resource intensive. The platform-integrated algorithm recorded 251 swaps over two months, preventing 4,137 kg CO₂ emissions, 6,809 m³ of water use, 3.08 m²a crop eq of land use, and 87.23 GJ of energy consumption. These findings highlight the significant environmental benefits of prolonging clothing use through swapping instead of throwing clothes away
Sulfur emission dependence on various factors during biomass combustion /
No full textThe transition from fossil fuels to renewable energy sources often requires shifting toward biomass fuels such as agriculture residues and waste, which tend to emit higher emission rates during combustion, and one of them is sulfur compounds. The main objective of this study is to clarify the regularities of the formation of sulfur compounds depending on the technological factors when burning sulfur-containing biomass. The experiments were conducted on two experimental stands—models of 20 kW and 25 kW capacities of industrial boilers equipped with reciprocating grates—by burning sunflower husk pellets and meat bone meal. The influence of incomplete combustion (indicator CO concentration), flue gas recirculation, and combined effects of both factors on concentrations of SO2, SO3, and H2S were investigated during experiments. In addition, 20–90% of the sulfur in the fuel is converted to SO2, contingent upon the combustion conditions. These findings have practical implications for the design and operation of biomass combustion systems. The highest SO2 emissions were observed when primary air was mixed with flue gas recirculation and at the highest content of CO. The correlation of SO2 and SO3 and SO2 and H2S concentrations in flue gases of boilers was investigated. The conversion ratio of SO2 to SO3 was determined under different combustion modes and showed that this ratio can reach up to 5%. The sulfur content in ash deposits in different areas of the actual industrial boiler was analyzed. The highest percent of sulfur (S = 20%) in ash was found on the first boiler pass
Virucidal efficacy of laser-generated copper nanoparticle coatings against model coronavirus and herpesvirus /
No full textHigh-efficiency antiviral surfaces can be an effective means of fighting viral diseases, such as the recent COVID-19 pandemic. Copper and copper oxides, their nanoparticles (NPs) (CuNPs), and coatings are among the effective antiviral materials having internal and external biocidal effects on viruses. In this work, CuNP colloids were produced via femtosecond laser ablation of the metal target in water, a photophysical, cost-effective green synthesis alternative utilizing sodium citrate surfactant stabilizing the NPs. Raman spectroscopy and X-ray diffraction studies confirmed that the 32 nm mean size CuNPs are mixtures of mainly metallic copper and copper(I) oxide. Polyvinyl butyral was utilized as the binding agent for the CuNPs deposited via high-throughput spray-coating technology. The virucidal efficacy of such coatings containing Cu content ranging from 2.9 to 11.2 atom % was confirmed against animal-origin coronavirus containing ribonucleic acid, the agent of avian infectious bronchitis (IBV), and herpesvirus containing DNA, the agent of bovine herpesvirus (BoHV-1) infection. It was demonstrated that after a short time of exposure, the Cu NP-based coatings do not have a toxic effect on the cell cultures while demonstrating a negative effect on the biological activity of both model viruses that was confirmed by quantification of the viruses via the determination of tissue culture infectious dose (TCID50) virus titer and their viral nucleic acids via determination of threshold cycle (Ct) employing real-time polymerase chain reaction analysis. The assays showed that the decrease in TCID50 virus titer and increase in Ct values correlated with Cu content in Cu NP-based coatings for both investigated viruses. Contact with coatings decreased IBV and BoHV-1 numbers from 99.42% to 100.00% and from 98.65% to 99.96%, respectively. These findings suggest that CuNPs show inhibitory effects leading to the inactivation of viruses and their nuclei regardless of the presence of a viral envelope
Visionary intellectual capital landscapes: an invitation for discussion /
No full textThis chapter is an editorial overview and interpretation of the most critical topics concerning future development of intellectual capital (IC) theory, research and practice. Based on the 16 ground-breaking and future-oriented core chapters in this book, we identify eight emerging themes for futurizing the feld of IC: 1) the need for multilevel approach towards IC; 2) an examination of IC dynamics; 3) redefning of value and economic models at the basis of IC; 4) a better recognition of sustainability and ethics in IC research; 5) a focus on the role of AI in IC; 6) a renewed emphasis on humans and culture; 7) a focus on non-rational and non-technological aspects of IC; and 8) an interdisciplinary approach towards research. We also compile a list of theoretical and practical highlights to futurizing IC, provided by the authors of the individual chapters in this book. The ideas presented in this chapter contribute to opening up new perspectives for the development of IC theory and practice, and inviting scholars and practitioners to a global and future-oriented discussion on IC
Synthesis of 1,3,4-thiadiazole amide derivatives /
No full text1,3,4-Thiadiazoles are important five-membered heterocyclic compounds found in the structures of various drugs and possessing antimicrobial, antifungal [1], anticancer [2], insecticidal [3], antiviral [4], and herbicidal [5] biological activities. [...]