Semi-Automated Roller Parameters Extraction from Terrestrial Lidar

Rollers are an integral part of a hot-rolling steel mill. They transport hot metal from one end of the mill to another. The quality of the steel highly depends on the surface quality of the rollers. This paper presents semi-automated methodologies to extract roller parameters from terrestrial lidar points. The procedure was divided into two steps. First, the three-dimensional points were converted to a two-dimensional image to detect the extents of the rollers using fast Fourier transform image matching. Lidar points for every roller were iteratively fitted to a circle. The radius and center of the fitted circle were considered as the average radius and average rotation axis of the roller, respectively. These parameters were also extracted manually and were compared to the measured parameters for accuracy analysis. The proposed methodology was able to extract roller parameters at millimeter level. Erroneously identified rollers were identified by moving average filters. In the second step, roller parameters were determined using the filtered roller points. Two data sets were used to validate the proposed methodologies. In the first data set, 366 out of 372 rollers (97.3%) were identified and modeled. The second, smaller data set consisted of 18 rollers which were identified and modelled accurately.

Kepler-411 Star Activity: Connection between Starspots and Superflares

Stellar magnetic activity, just like that of the Sun, manifests itself in the form of flares and spots on the surface of the star. In the solar case, the largest flares originate from large active regions. In this work, we present a study of the activity of the star Kepler-411, including spot modeling from planetary transits. Our goal was to search for a connection between the area of starspots with the energy of superflares produced by this star. Kepler-411 is a K2V-type star with an average rotation period of 10.52 days, radius of 0.79 R ⊙, and a mass of 0.83 M ⊙, which was observed by the Kepler satellite for about 600 days. Transit mapping allowed for the characterization of 198 starspots with estimates of their radius and temperature. Kepler-411 starspots had an average radius of (17 ± 7) × 103 km and a mean temperature of 3800 ± 700 K. Visual inspection of the light curves of Kepler-411 yields the identification of 65 superflares. The detected superflares lasted from 8 to 260 minutes and their energy varied from 1033–1035 ergs. The power-law index of the flare frequency distribution as a function of energy is (−2.04 ± 0.13) for the flare on Kepler-411. A positive correlation between the area of starspots and the energy of superflares was found when considering the averages taken every 16–35 days, with the highest correlation occurring for averages every 21 days. This timing is probably related to the lifetime of the Kepler-411 spots.

The rotation of Ganymede and Callisto

<p>The rotation rates of Ganymede and Callisto, the two largest satellites of Jupiter, are on average equal to their orbital mean motion but cannot be constant as a result of the varying gravitational torque exerted by Jupiter on the satellites. For a Keplerian orbit, the period of the torque and of the rotation variations is equal to the orbital period. Gravitational interaction with the other Galilean satellites and the Sun induces deviations from a purely Keplerian orbital motion, leading to changes in the gravitational torque of Jupiter on the satellites with respect to the mean Keplerian orbital motion and therefore to additional rotation variations. Here we discuss small variations from the average rotation on different time scales and assess the potential of using rotation as a probe of the interior structure.</p> <p>The ESA JUICE (JUpiter ICy moons Explorer) mission will measure the rotation and tides of Ganymede and Callisto in the early 30s, and will in particular very accurately determine those quantities for Ganymede during the orbital phase of the spacecraft around that satellite starting in 2032. We report on different theoretical aspects of the rotation for realistic models of the interior of the satellites, include tidal deformations and take into account the low-degree gravity field and topography of Ganymede and Callisto. We assess the advantages of a joint use of rotation and tides to constrain the satellite's interior structure, in particular its ice shell and ocean.</p>

How to Increase Biodiversity of Saproxylic Beetles in Commercial Stands through Integrated Forest Management in Central Europe

Due to traditional forest management, the primary goal of which is the production of raw wood material, commercial forest stands are characterized by low biodiversity. At the same time, commercial forests make up the majority of forests in the Central European region, which means a significant impact on the biodiversity of the entire large region. Saproxylic species of organisms are a frequently used criterion of biodiversity in forests. Based upon the analysis of 155 scientific works, this paper defines the fundamental attributes of the active management supporting biodiversity as well as the preservation of the production function. Using these attributes, a model management proposal was created for three tree species, which takes into account the results of research carried out in the territory of the University Forest Enterprise of the Czech University of Life Sciences Prague, since 2019. The optimum constant volume of deadwood in commercial stands was set at 40–60 m3/ha, 20% of which should be standing deadwood. The time framework is scheduled for an average rotation period of the model tree species, while the location of deadwood and frequency of enrichment must comply with the rate of decomposition, the requirement for the bulkiest dimensions of deadwood possible, and the planned time of tending and regeneration operations in accordance with the models used in the Czech Republic. The goal of active management is to maintain the continuity of suitable habitats for sensitive and endangered species. The estimates of the value of retained wood for decomposition can be as high as 45–70 EUR/ha/year for spruce and beech, and about 30 EUR /ha/year for oak.

Application of a Vision-Based Single Target on Robot Positioning System

In this paper, we propose a Circular-ring visual location marker based on a global image-matching model to improve the positioning ability in the fiducial marker system of a single-target mobile robot. The unique coding information is designed according to the cross-ratio invariance of the projective theorem. To verify the accuracy of full 6D pose estimation using the Circular-ring marker, a 6 degree of freedom (DoF) robotic arm platform is used to design a visual location experiment. The experimental result shows in terms of small resolution images, different size markers, and long-distance tests that our proposed robot positioning method significantly outperforms AprilTag, ArUco, and Checkerboard. Furthermore, through a repeatable robot positioning experiment, the results indicated that the proposed Circular-ring marker is twice as accurate as the fiducial marker at 2–4 m. In terms of recognition speed, the Circular-ring marker processes a frame within 0.077 s. When the Circular-ring marker is used for robot positioning at 2–4 m, the maximum average translation error of the Circular-ring marker is 2.19, 3.04, and 9.44 mm. The maximum average rotation error is also 1.703°, 1.468°, and 0.782°.

QGIS processing tool for spatial data detail assessment

The article is devoted to the problem of evaluating the detailing of spatial data. In geoinformatics, spatial data detailing determines how detailed a particular object is representeda map image, and the detail score allows you to analyze the permissible accuracy of spatial objects for a specific user task. An approach to the definition of detailing concept is proposed. The evaluation of the object’s detail depends on its characteristics: geometric, semantic, and topological. A study is being conducted to select the geometric characteristics of the object that reflect its detail. For linear objects, in addition to the characteristics of the line as a whole (length, number of points, sinuosity, average rotation angle), it is suggested to consider its smaller details, such as bends and triplets. A bend is a section of a line where the angle of rotation retains its sign. A triplet is a combination of three consecutive points. Based on the results of the study, the geometric characteristics that change in the trend depending on the scale were selected. The paper presents the developed software for assessing map detail—the MapAnalyser toolbar for the QGIS geoinformation system. The functional capabilities of the developed software are described. The toolbar allows you to get the geometric, semantic, and topological characteristics of a layer or set of layers, as well as to evaluate the graphical complexity of a map image based on RlE encoding. The program code is written in the PyQGIS language. The software has passed state registration and is hosted on the github server. With its help, new results were obtained on the evaluation of spatial data granularity. New software, embedded in QgIS, to assess the detail of the map and spatial data, based on taking into account geometric and symbolic (used in the display) parameters. The software allows to calculate the metrics of spatial data detail, as well as to assess the complexity of the cartographic image. It’s can be used in the integration of data obtained from different sources, assess the compliance of data detail and the map scale, to assess the complexity of the map for different purposes and scales.

ANALISIS PEMBANGKIT LISTRIK MENGGUNAKAN TURBIN ANGIN SAVONIUS

ABSTRAK Turbin angin tipe Savonius adalah salah satu turbin angin poros vertikal (VAWT) dengan konstruksi sederhana yang memiliki rotor utama berputar secara vertikal. Kelebihannya adalah dapat memanfaatkan angin dari segala arah, mampu bekerja dengan kecepatan rendah, serta ia tidak membutuhkan menara yang terlalu tinggi. Tujuan dari penelitian ini adalah untuk menganalisis kinerja turbin berdasarkan rotasi dan output generator beban. Metode yang digunakan adalah melakukan pengukuran langsung putaran turbin dan generator dalam kondisi tanpa beban dan kondisi muatan. Hasil penelitian diperoleh kecepatan angin rata-rata di desa Oenali adalah 4,64 m/s, dan turbin ini yang mampu memutar turbin Savonius dengan putaran rata-rata 631 rpm. Kemudian, pada putaran generator 1.243 rpm mampu menghasilkan daya output sebesar 7,20 watt. Selain itu, efisiensi generator rata-rata sebesar 36%, efisiensi harian tertinggi adalah 38%, dan efisiensi harian terendah adalah 35% ABSTRACT Savonius type wind turbines are one of the vertical shaft wind turbines (VAWT) with a simple construction that has a vertically rotating main rotor. The advantage is that it can take advantage of the wind from all directions, is able to work at low speeds, and it does not need a tower that is too high. The purpose of this study is to analyze the performance of the turbine based on the rotation and output of the load generator. The method used is to measure directly the rotation of the turbine and generator under no-load and load conditions. The results showed an average wind speed in Oenali village was 4.64 m / s, and this turbine was able to rotate Savonius turbines with an average rotation of 631 rpm. Then, the generator speed of 1,243 rpm can produce an output power of 7.20 watts. In addition, the average generator efficiency is 36%, the highest daily efficiency is 38%, and the lowest daily efficiency is 35%.

The rotation and interior of Ganymede

<p>The rotation rate of Ganymede, the largest satellite of Jupiter, is on average equal to its orbital mean motion but cannot be constant on orbital time scale as a result of the gravitational torque exerted by Jupiter on the moon. Here we discuss small deviations from the average rotation rate, evaluate polar motion, and discuss Ganymede's obliquity. We examine different time scales, from diurnal to long-period, and assess the potential of using rotation as probes of the interior structure.</p><p>The ESA JUICE (JUpiter ICy moons Explorer) mission will accurately measure the rotation of Ganymede during its orbital phase around the satellite starting in 2032. We report on different theoretical aspects of the rotation for realistic models of the interior of Ganymede, include tidal deformations and take into account the low-degree gravity field and topography of Ganymede. We assess the advantages of a joint use of rotation and tides to constrain the satellite's interior structure, in particular its ice shell and ocean.</p>

A diagnostic diagram for γ Doradus variables and slowly pulsating B-type stars

Pulsating variables of γ Doradus type (γ Dor) and slowly pulsating B-type (SPB) stars are found on and near the main sequence with typical periods varying between one and several days, making them rather hard to detect from the ground. It is only with space missions such as CoRoT and Kepler that we became truly capable of determining their oscillation frequencies with enough precision to perform in-depth analyses. Here we present an efficient and easy-to-implement seismic tool, in which the frequency (ν) and the square root of the frequency difference ($ \sqrt{\Delta \nu} $) are plotted against each other as the abscissa and the ordinate, respectively. This allows us to immediately (1) perform mode identification; (2) estimate the average rotation rate and the characteristic period of gravity modes; and (3) recognise certain physical effects, including buoyancy glitches and avoided crossings. This diagnostic tool can only be applied to prograde sectoral g modes. To validate the tool presented here, we used stellar models and also applied it to three γ Dor (KIC 12066947, KIC 5608334 and KIC 4846809) and one SPB star (KIC 3459297), all observed with Kepler. Furthermore, we show that the rotation rates determined using this new tool are consistent with the results of previous studies.

ALMA reveals a large structured disk and nested rotating outflows in DG Tauri B

We present Atacama Large Millimeter Array (ALMA) Band 6 observations at 14−20 au spatial resolution of the disk and CO(2-1) outflow around the Class I protostar DG Tau B in Taurus. The disk is very large, both in dust continuum (Reff, 95% = 174 au) and CO (RCO = 700 au). It shows Keplerian rotation around a 1.1 ± 0.2 M⊙ central star and two dust emission bumps at r = 62 and 135 au. These results confirm that large structured disks can form at an early stage where residual infall is still ongoing. The redshifted CO outflow at high velocity shows a striking hollow cone morphology out to 3000 au with a shear-like velocity structure within the cone walls. These walls coincide with the scattered light cavity, and they appear to be rooted within < 60 au in the disk. We confirm their global average rotation in the same sense as the disk, with a specific angular momentum ≃65 au km s−1. The mass-flux rate of 1.7−2.9 × 10−7 M⊙ yr−1 is 35 ± 10 times that in the atomic jet. We also detect a wider and slower outflow component surrounding this inner conical flow, which also rotates in the same direction as the disk. Our ALMA observations therefore demonstrate that the inner cone walls, and the associated scattered light cavity, do not trace the interface with infalling material, which is shown to be confined to much wider angles (> 70°). The properties of the conical walls are suggestive of the interaction between an episodic inner jet or wind with an outer disk wind, or of a massive disk wind originating from 2 to 5 au. However, further modeling is required to establish their origin. In either case, such massive outflow may significantly affect the disk structure and evolution.