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Found 6327 publications
A method to accurately define arbitrary algorithmic damping character as viscous damping
Publication Name: Archive of Applied Mechanics
Publication Date: 2023-09-01
Volume: 93
Issue: 9
Page Range: 3581-3595
Description:
Undesired oscillations often emerge in numerical solutions, especially in the case of dynamic problems. These are mainly spurious oscillations which must be eliminated or reduced at least to provide accurate results. Numerical methods with damping effect are especially useful to achieve this goal. However, the concrete shape of the damping characteristics has a great impact on the effectiveness. Dissipative numerical methods mostly have a specific damping character with very limited alteration possibility. In this article, a novel numerical method has been introduced where the dissipative effect is exerted via viscous damping. Using the proposed method, a great variety of damping curves can be defined accurately, straight through the determination of the algorithmic damping ratio. The newly developed technique is mainly useful for applications where the shape of the damping characteristics significantly affects the accuracy.
Open Access: Yes
Cataloguing microalgae and Cyanobacteria strains from the Mosonmagyaróvár Algal Culture Collection with in vitro antagonistic activity against phytopathogenic fungi and oomycetes
Publication Name: Phytoparasitica
Publication Date: 2023-09-01
Volume: 51
Issue: 4
Page Range: 747-762
Description:
Microalgae produce many secondary metabolites that are biologically active, including compounds that inhibit microbial growth. These could potentially function as biofungicides. The first selection criteria for potential strains suitable in the phytosanitary market is good in vitro inhibition of growth against specific phytopathogenic fungi and oomycetes and higher biomass productivity rates. In the present study, water extracts were prepared from 280 strains comprising of 33 Cyanophyceae strains (13 genera), 157 Chlorophyceae strains (29 genera), 80 Trebouxiophyceae strains (19 genera), 5 Klebsormidiophyceae strains (1 genus) and 1 Zygnematophyceae strain. These were tested in vitro against 6 phytopathogenic fungi and 3 phytopathogenic oomycetes. In total, 45% of the species had mycelial growth inhibitory activity against at least one pathogen. Cyanobacteria had the highest “hit-rate” (64%), followed by the Chlorophyceae (49%) and Trebouxiophyceae (30%). Water extracts of 19 strains had fungicidal and/or oomyceticidal activity – these were predominantly Cyanobacteria. The Cyanobacteria displayed a wider spectrum of inhibition with five strains being active against three or more phytopathogenic strains. Trichormis variabilis MACC-304 and Tolypothrix tenuis MACC-205 had inhibitory activity against 6 phytopathogens and Nostoc linckia MACC-612 inhibited 4 phytopathogenic strains. Each Chlorophyta strain was only active against 1-2 strains. However, the daily productivity rates of Cyanobacteria were significantly lower than Chlorophyta strains. Further investigation of 15 Nostocales species (Nostocaceae, Tolypothrichaceae and Calotrichaceae) showed the Nostoc species generally had significantly lower biomass generation compared to other Nostocacaeae strains. The most promising strain was Tolypothrix tenuis MACC-205 which had the most potent, broad spectrum fungal and oomyceticidal inhibitory activity as well as significantly higher daily biomass productivity rates. Thus, Cyanobacteria can potentially be developed as an effective agricultural tool for environmentally-friendly disease management.
Open Access: Yes
Accuracy of the robust design analysis for the flux barrier modelling of an interior permanent magnet synchronous motor
Publication Name: Journal of Computational and Applied Mathematics
Publication Date: 2023-09-01
Volume: 429
Issue: Unknown
Page Range: Unknown
Description:
Mass-produced electrical machines are subjected to manufacturing uncertainties in terms of geometry. A robust design is inevitable to ensure the consistent performance of the electric motor. Some parts of the rotor geometry are often simplified, like the flux barrier at the end of the magnets. This paper presents a design optimisation regarding the torque ripple and the average torque. The aim is to assess the effects of the flux barrier on the main properties of a permanent magnet synchronous motor. Also, robust design analysis is presented on the flux barrier. The computational burden of the robust design analysis is immense, even if uniform uncertainties are assumed. In this case, different Design of Experiment (DoE) methods reduce the number of simulations. The efficiency of the DoE methods is compared in terms of simulation number and extreme value approximation. We found that the Central Composite method is the most accurate, while the Plackett–Burman is the most efficient in this particular case.
Open Access: Yes
Potential benefit of microalgae and their interaction with bacteria to sustainable crop production
Publication Name: Plant Growth Regulation
Publication Date: 2023-09-01
Volume: 101
Issue: 1
Page Range: 53-65
Description:
Agriculture is undergoing a paradigm shift as it moves away from relying only on agrochemicals toward natural-based product to enhance plant growth and productivity while sustainably maintaining soil quality and productivity. In this sense, microalgae and bacteria offer a unique potential due to the growing use of novel and eco-friendly products such as biofertilizers, biostimulants, and biopesticides. Microalgae improve crop growth and health by fixing nitrogen, releasing soil trace elements, solubilizing potassium, and phosphorus, producing exopolysaccharides, and converting organic matter into utilizable nutrients. They also release bioactive substances including, carbohydrates, proteins, enzymes, vitamins, and hormones, to promote plant growth, control pests, and mitigate plant stress responses. Even though it has long been known that microalgae produce various bioactive and signaling molecules (like phytohormones, polysaccharides, lipids, carotenoids, phycobilins, and amino acids) which are effective in crop production, the targeted applications of these molecules in plant science are still in the very early stages of development. Microalgae are beneficial to bacteria because they produce oxygen and extracellular chemicals, and bacteria, in turn, provide microalgae with carbon dioxide, vitamins, and other nutrients in exchange. This review discusses the possible role of microalgae in increasing crop yield, protecting crops, and maintaining soil fertility and stability, and it points out that interactions of microalgae and bacteria may have a better enhancement of crop production in a sustainable way than using either of them alone.
Open Access: Yes
Lignocellulosic agro-residue/polylactic acid (PLA) biocomposites: Rapeseed straw as a sustainable filler
Publication Name: Cleaner Materials
Publication Date: 2023-09-01
Volume: 9
Issue: Unknown
Page Range: Unknown
Description:
The main objective of this study is to review the applicability of rapeseed straw (RSS) as a sustainable filler material in polylactic acid (PLA)-based biocomposites. The effect of different RSS particle sizes and concentrations (0–20 wt%) on the mechanical, morphological, thermal, and water absorption properties was investigated. The composites were fabricated by melt compounding using a twin-screw extruder followed by injection molding. The mechanical properties were analyzed through tensile and flexural tests and Charpy impact tests. The morphology of the samples was investigated by scanning electron microscopy (SEM). The thermal properties and the crystallinity of the composites were determined through differential scanning calorimetry (DSC). Mechanical properties revealed an increasing stiffness of PLA as a function of RSS loading, albeit at the cost of strength. SEM images have shown a limited interfacial adhesion between PLA and the straw, which was suggested to be responsible for the decreased strength values. Based on the DSC measurements, the RSS fibers facilitated the nucleation in the composites, thereby decreasing the cold crystallization temperature of PLA. The conducted experiments demonstrated that environmentally friendly and economically attractive biocomposites can be fabricated by substituting part of the PLA with RSS as a lignocellulosic by-product.
Open Access: Yes
Work from home practices as corporate strategy- an integrative review
Publication Name: Heliyon
Publication Date: 2023-09-01
Volume: 9
Issue: 9
Page Range: Unknown
Description:
The Covid 19 pandemic led to major changes at the individual, organisational and institutional levels of policy, productive functions, and organising. During Covid 19 morbidity, public institutions enforced social isolation, mandatory self-isolation, quarantines, and administrative regulatory lockdowns, which led to a movement away from the physical, material world and into an all-consuming digital universe. With growing interest in work-from-home (WFH) opportunities, this article provides an integrative review of 107 papers. It comprises the bibliometric analysis and manual review of the articles, on the basis of which we present an elaborative discussion and agenda for future research. According to the analysis, WFH looks a tad of a double-edged sword in that it may have major but unintended repercussions for institutions, and organizations as well as hidden, positive as well as negative consequences for individuals/employees. One of the significant insight from our analysis was the absence of HR function's strategic or operational input or oversight during corporate WFH strategies. We suggest several theoretical frameworks for further developing, theorizing, and empirically testing various aspects of WFH. Further, we recognise that WFH is becoming increasingly visible as a result of the pandemic scenario and significant technical advancements, which must be reflected in the research. Finally, because WFH represents a significant disruption in how organizations produce work and manage it, we propose employee and managerial consequences as future research agendas.
Open Access: Yes
Experimental Wear Analysis of Nano-Sized Titania Particles as Additives in Automotive Lubricants
Publication Name: Micro
Publication Date: 2023-09-01
Volume: 3
Issue: 3
Page Range: 715-727
Description:
This study focuses on the wear effects of nano-sized titania as a potential engine lubricant additive. Titanium dioxide nanoparticles have promising wear-reducing properties and significant tribological potential. In this article, titania nanoparticles were homogenized in Group III automotive oil at five different concentrations (0.1; 0.2 … 0.5 wt%). The nanodoped oil samples were tested on a linear oscillating tribometer with oil circulation. Based on the tribological results, titania nanoparticles increased friction by 20–32% but can reduce the wear area by up to 32%. According to the confocal microscopic examination, wear volume can be reduced by up to 57% with titania nanoparticles. Titania nanoparticles improved the repeatability of tribological measurements. A scanning electron microscopy examination of the wear track revealed that the characteristic wear of the tribological system was abrasive, but a significant amount of adhesive wear was also observed. Energy dispersive X-ray spectroscopy analysis found that the nanoparticles fill the deeper trenches of the wear. The worn surface uniformly contains TiO2 particles and the quantified normalized titanium concentration was between 0.56 and 0.62%.
Open Access: Yes
DOI: 10.3390/micro3030050
Outer ear reconstruction using 3D technology Materials, methods and applicability in use cases
Publication Name: Current Directions in Biomedical Engineering
Publication Date: 2023-09-01
Volume: 9
Issue: 1
Page Range: 1-4
Description:
Manufacturing replicas for replacing missing or defective body parts also incorporates 3D technology, including scanning, image processing and printing. In the case of the ears, both aesthetics and functionality play a significant role. Based on these techniques, outer ear replicas were produced using 3D scans of human skulls in a rapid prototyping procedure for actual patients. Hand-held scanners delivered accurate images for post-processing of the mesh and for printing in a cost- and time efficient way. Use cases of patients demonstrate applicability, allowing the technology to be available also for the general population in the future.
Open Access: Yes
Reliability based topology optimization of thermoelastic structures using bi-directional evolutionary structural optimization method
Publication Name: International Journal of Mechanics and Materials in Design
Publication Date: 2023-09-01
Volume: 19
Issue: 3
Page Range: 605-620
Description:
The aim of this paper is to propose a novel computational technique of applying reliability-based design to thermoelastic structural topology optimization. Therefore, the optimization of thermoelastic structures' topology based on reliability-based design is considered by utilizing geometrical nonlinearity analysis. For purposes of introducing reliability-based optimization, the volume fraction parameter is viewed as a random variable with a normal distribution having a mean value and standard deviation. The Monte Carlo simulation approach for probabilistic designs is used to calculate the reliability index, which is used as a constraint related to the volume fraction constraint of the deterministic problem. A new bi-directional evolutionary structural optimization scheme is developed, in which a geometrically nonlinear thermoelastic model is applied in the sensitivity analysis. The impact of changing the constraint of a defined volume of the required design in deterministic problems is examined. Additionally, the impact of altering the reliability index in probabilistic problems is investigated. The effectiveness of the suggested approach is shown using a benchmark problem. Additionally, this research takes into account probabilistic thermoelastic topology optimization for a 2D L-shaped beam problem.
Open Access: Yes
