Padlet – ocenianie rówieśnicze

Cykl: Dasie i Niedasie: https://www.cel.agh.edu.pl/dasie-i-niedasie/film instruktażow

Discrete and Continuous Dynamical Systems

The Restricted Planar Circular 3-Body Problem models the mo- tion of a body of negligible mass under the gravitational influence of two mas- sive bodies, called the primaries, which perform circular orbits coplanar with that of the massless body. In rotating coordinates, it can be modelled by a two degrees of freedom Hamiltonian system, which has five critical points called the Lagrange points. Among them, the point L3 is a saddle-center which is collinear with the primaries and beyond the largest of the two. The papers [3, 4] provide an asymptotic formula for the distance between the one dimensional stable and unstable manifolds of L3 in a transverse section for small values of the mass ratio 0 < μ ≪ 1. This distance is exponentially small with respect to μ and its first order depends on what is usually called a Stokes constant. The non-vanishing of this constant implies that the distance between the invariant manifolds at the section is not zero. In this paper, we prove that the Stokes constant is non-zero. The proof is computer assisted.preprin

LaTeX w Moodle – równania matematyczne

Cykl: Dasie i Niedasie: https://www.cel.agh.edu.pl/dasie-i-niedasie/film instruktażow

Geomatics and Environmental Engineering

This article focuses on low-cost LiDAR (light detection and ranging) sensors and 3D depth cameras. Particular attention was paid to their accuracy and compliance with the technical specifications that were provided by their respective manufacturers. The following devices were tested: Stereolabs ZED 2i, Stereolabs ZED, and Intel RealSense D435i depth cameras, and the Intel RealSense L515 LiDAR sensor. An experiment was carried out to measure a geometrically diverse environment (which is typical for in-motion imaging) where both the measurement range and the distortion that is generated by each device’s algorithms on edges, folds, planes, and 3D objects could be evaluated. Depth sensors are often used with excessive confidence as to their geometric reliability. The aim of this work is to assess the actual accuracy of such sensors, which may constitute the ground truth for accuracy losses that could result from the operations of autonomous vehicles. Based on the results, the accuracy information that was provided by the respective manufacturers was difficult to obtain under real conditions. It was found that the low-cost devices could be used in industrial projects, but their operations must take place under certain conditions and settings. It was also necessary to know their capabilities and limitations in order to take full advantage of what they offer.Krakówwersja wydawnicz

Geomatics and Environmental Engineering

This article is devoted to studying the peculiarities of applying the valuation approach toward assessing the efficiency of agricultural land use. In particular, it was determined that the main link of the valuation approach was the value of the land use. Value is the basis of quantitative correlation under the equivalent exchange, the value of land use can be determined by applying three common approaches: comparison, cost, and income. The authors of the research present a methodology for assessing the value of the right to manage agricultural land use and its efficiency. The work supplies the calculated book value of land use under the actual status of agricultural lands in Ukraine according to the average indicators (in the present research, this was the period of 2017–2021) and the economic market value of land use while considering innovative investments in land improvement that are focused on establishing the more effective use of agricultural lands. It is stated that the valuation approach toward assessing the efficiency of agricultural land use can be used to specify the value of the right to manage land use in the amount of its general value as well as assess its efficiency. The suggested algorithm and statistical indicators were used to calculate the right and efficiency of agricultural land use management for all categories of farms and, particularly, in terms of agricultural enterprises of the different forms of economic activity.Krakówwersja wydawnicz

Opuscula Mathematica

In this note we show that given an indeterminate Hamburger moment sequence, it is possible to perturb the first moment in such way that the obtained sequence remains an indeterminate Hamburger moment sequence. As a consequence we prove that every sequence of real numbers is a moment sequence for a signed discrete measure supported in $\mathbb{R}_{+}$.Krakówwersja wydawnicz

Opuscula Mathematica

We consider an elliptic equation driven by a nonlinear, nonhomogeneous differential operator with nonstandard growth. The reaction has the combined effects of a singular term and of a "superlinear" perturbation. There is no parameter in the problem. Using variational tools and truncation and comparison techniques, we show the existence of at least two positive smooth solutions.Krakówwersja wydawnicz

Chemical Engineering Journal

The escalating global water crisis necessitates innovative approaches to developing sustainable water resources. Fog water collectors with variable surface wettability offer controlled fog harvesting in water-scarce regions. This study develops thermoresponsive fog collecting materials by electrospinning poly(N-isopropylacrylamide)-polyvinylidene fluoride (PNIPAm-PVDF) into yarns that are transformed into harp-like structures for enhanced water harvesting rate. Both meshes and harps using electrospun membranes exhibit the remarkable ability to transition between hydrophilic and hydrophobic wetting states at temperatures below the lower critical solution temperature (LCST). Hydrophilic and hydrophobic surfaces play distinct roles in fog water collection. Hydrophilic surfaces have a high affinity for water and enables droplet capture. Hydrophobic surfaces help the removal of aggregated water droplet and fog water collection. The highest water collection rate obtained with the electrospun PNIPAm-PVDF harp was 1415 ± 7.0 mg·cm−2 h−1. The water harvesting system based on the electrospun PNIPAm-PVDF harps exhibits a 485 % increase in water collection compared to the standard meshes made from the same material, emphasizing their potential for significantly improving the overall rate in fog water harvesting applications.wersja wydawnicz

Opuscula Mathematica

The sub-Brownian 3-isometries in Hilbert spaces are the natural counterparts of the 2-isometries, because all of them have Brownian-type extensions in the sense of J. Agler and M. Stankus. We show that all powers $T^n$ for $n\geq 2$ of every expansive 3-isometry $T$ are sub-Brownian, even if $T$ does not have such a property. This fact induces some useful relations between the corresponding covariance operators of $T$. We analyze two matrix representations of $T$ in order to get some conditions under which $T$ is sub-Brownian, or $T$ admits the Wold-type decomposition in the sense of S. Shimorin. We show that the restriction of $T$ to its range is sub-Brownian of McCullough's type, and that under some conditions on $\mathcal{N}(T^*)$, $T$ itself is sub-Brownian, and it admits the Wold-type decomposition.Krakówwersja wydawnicz

Mining - Informatics, Automation and Electrical Engineering

Greenhouse gases and their emissions are issues that are being increasingly discussed due to climate change. Next to carbon dioxide, methane is considered one of the most important greenhouse gases. Reducing methane emissions could result in noticeable environmental benefits in a short time. Anthropogenic emissions constitute approximately 60 of total methane emissions and thus solutions to reduce emissions of this gas are most often sought in this sector. The subject of the study is the methane capture system in the “Pniówek” mine, belonging to the Upper Silesian Coal Basin (southern Poland), and the potential for methane management using a trigeneration system. The article discusses the utilization of methane from hard coal mines to reduce its emissions into the atmosphere and as a profitable solution to use the emitted gas. The authors describe a trigeneration system in which methane from the mine is burned in gas engines and used to produce electricity, heat, and cooling energy. This allows for reducing methane emissions into the atmosphere while increasing the efficiency of coal use. The article shows the results of measurements carried out in a hard coal mine in Poland. The presented example indicates the ecological and economic benefits resulting from the use of a trigeneration system.Krakówwersja wydawnicz