10 research outputs found
Factors affecting the persistence of traditional agricultural landscapes in Slovakia during the collectivization of agriculture
Collectivization of agriculture (1950s-1970s) was one of the most important periods in landscape development in Slovakia. Traditionally managed agricultural landscapes, that covered more than half of the Slovak territory, were transformed into large-scale fields and only fragments of traditional agricultural landscapes survived. We mapped the remaining traditional agricultural landscapes using aerial photos and historical maps. We then statistically analyzed the various geographical factors and their influence on the transformation process of traditional and collectivized fields, i.e., slope steepness, soil fertility, distance from settlements and isolation from regional capital cities. The comparison was performed using classification tree analysis. We constructed a set of decision rules that explain why fields were managed traditionally or collectivized. Our findings show that traditional agricultural fields were more likely to persist on steep terrain, less fertile soils, and on locations that were closer to the settlements, but more isolated from the regional capital cities. Steepness played the most important role: small-scale fields located on steep areas were not accessible to heavy machinery and therefore, frequently survived the collectivization. We show that the selected geographical factors are good explanatory variables for the collectivization of arable fields and orchards. For vineyards and grasslands, however, the explanatory power of the selected geographical factors is lower, and we suspect that other factors, not depicted in the analysis play an important role
The peak-flux of GRB 221009A measured with GRBAlpha
The brightest gamma-ray burst ever observed, long-duration GRB 221009A, was
detected by GRBAlpha nano-satellite without saturation. We present light curves
of the prompt emission in 13 energy bands, from 80 keV to 950 keV, and perform
a spectral analysis to calculate the peak flux and peak isotropic-equivalent
luminosity. Since the satellite's attitude information is not available for the
time of this GRB, more than 200 incident directions were probed in order to
find the median luminosity and its systematic uncertainty. We found that the
peak flux in the keV range (observer frame) was
ph cms or
erg cms
and the fluence in the same energy range of the first GRB episode lasting 300
s, which was observable by GRBAlpha, was erg
cm or erg cm for
the extrapolated range of keV. We infer the isotropic-equivalent
released energy of the first GRB episode to be
erg in the
keV band (rest frame at ). The peak isotropic-equivalent luminosity in
the keV range (rest frame) was
erg s and the
bolometric peak isotropic-equivalent luminosity was
erg s (4 s
scale) in the keV range (rest frame). The peak emitted energy is
keV. Our measurement of
is consistent with the Yonetoku relation. It is
possible that, due to the spectral evolution of this GRB and orientation of
GRBAlpha at the peak time, the true values of peak flux, fluence,
, and are even higher. [abridged]Comment: 7 pages, 7 figures, 1 table, accepted for publication in Astronomy &
Astrophysic
GRBAlpha: the smallest astrophysical space observatory -- Part 1: Detector design, system description and satellite operations
Aims. Since launched on 2021 March 22, the 1U-sized CubeSat GRBAlpha operates
and collects scientific data on high-energy transients, making it the smallest
astrophysical space observatory to date. GRBAlpha is an in-obit demonstration
of a gamma-ray burst (GRB) detector concept suitably small to fit into a
standard 1U volume. As it was demonstrated in a companion paper, GRBAlpha adds
significant value to the scientific community with accurate characterization of
bright GRBs, including the recent outstanding event of GRB 221009A. Methods.
The GRB detector is a 75x75x5 mm CsI(Tl) scintillator wrapped in a reflective
foil (ESR) read out by an array of SiPM detectors, multi-pixel photon counters
by Hamamatsu, driven by two separate, redundant units. To further protect the
scintillator block from sunlight and protect the SiPM detectors from particle
radiation, we apply a multi-layer structure of Tedlar wrapping, anodized
aluminium casing and a lead-alloy shielding on one edge of the assembly. The
setup allows observations of gamma radiation within the energy range of 70-890
keV with an energy resolution of ~30%. Results. Here, we summarize the system
design of the GRBAlpha mission, including the electronics and software
components of the detector, some aspects of the platform as well as the current
way of semi-autonomous operations. In addition, details are given about the raw
data products and telemetry in order to encourage the community for expansion
of the receiver network for our initiatives with GRBAlpha and related
experiments.Comment: Accepted for publication in Astronomy & Astrophysics, 9 pages, 10
figure
Measuring and Analysis Colour of Birch Wood in Digital Picture
The aim of the research was to verify a new method of measuring the colour of wood. The method was designed to automate wood colour measurement. In the experiments birch wood was used, which was heat treated with saturated water steam. Nikon D3200 camera was used in conjunction with the MATLAB program to implement the method. The assessments were conducted in the colour space of CIE L* a* b*. The measured values confirmed the decrease in lightness from natural to thermally modified wood. The trends of the colour values a* and b* were the same as those reported by the authors who conducted experiments with birch wood. Differences were found in the magnitude of the measured chromatic component a* values. It will be necessary to verify the above facts and determine the reasons for these differences by measuring the colour of other wood species
Measuring and analysis colour of birch wood in digital picture
The aim of the research was to verify a new method of measuring the colour of wood. The method was designed to automate wood colour measurement. In the experiments birch wood was used, which was heat treated with saturated water steam. Nikon D3200 camera was used in conjunction with the MATLAB program to implement the method. The assessments were conducted in the colour space of CIE L* a* b*. The measured values confirmed the decrease in lightness from natural to thermally modified wood. The trends of the colour values a* and b* were the same as those reported by the authors who conducted experiments with birch wood. Differences were found in the magnitude of the measured chromatic component a* values. It will be necessary to verify the above facts and determine the reasons for these differences by measuring the colour of other wood species
Optical Analysis of Fractional Particles
Analysis of fractal particles, like sawdust or dust, by sieve method is rather difficult in terms of the measuring system and time-consuming at samples evaluation. The results give only partial information of the particle dimensions in an examinable sample. Modern optical methods of fractal particles analysis in the industry complexly acquaint with the sample; they provide information about the particle rate and size, average, maximum and minimum occurring dimension, particle surface, and shape composition of a sample. In our experiment were evaluated wood particles with IP camera IQEye 702. Camera captures the scene with sawdust and send video via ethernet. In program Matlab is in time captured in this video one picture, which is further processed and in it are found measured particles. Subsequently are measured required parameters of captured particles
Impact of skeletonization methods on accuracy of digital holograms evaluation
The method of holographic interferometry has been applied to make the temperature fields over the heated-up wooden test specimens visible. We verified impact of skeletonization methods on accuracy of digital holograms evaluation. Individual thinning algorithms have individual approach to thinning and therefore resultant skeletons of digital holograms are different
Application of Selected Reverse Engineering Procedures Based on Specific Requirements
The paper describes a solution of reverse engineering tasks using the equipment of the laboratory of the Technical University in Zvolen. The first task was linked to evaluation of a wear rate of the tool used to for mulching and elimination of unwanted wood or weed vegetation. The obtained data will be used as a base line for determination of the time interval for the tool replacement. We developed a prototype of components and their drawing documentation for a single-purpose machine for cutting barley. We created the 3D model using the method of photogrammetry. The finished drawing documentation and prototypes were handed over to the company KRUP. Finally, we identified the most suitable procedures for creating a model of a part with a complex shape. We tested the techniques of editing the point cloud processing, as well as of smoothing the surfaces and automating the creation of partial geometric elements of the model. Based on the properties of the component, which is the starting point of the entire reverse engineering process and from the achieved results, we set recommendations for the selection of appropriate procedures
Experimental Granulometric Characterization of Wood Particles from CNC Machining of Chipboard
The aim of this paper is to determine the particle size composition of the wood particles obtained from CNC milling the chipboard using an experimental optical granulometric method. Composite materials (chipboard) are the most-used materials in the woodworking and furniture industries. The proposed optical method of measuring particles’ dimensions is compared to the sieving technique. The researched experimental method allows for the determination of not only the size of the fraction of an individual particle’s fraction but also more detailed information about the analyzed wood dust emission, for example, the largest and smallest dimension of each single particle; its circularity, area, perimeter, eccentricity, and convex hull major and minor axis length; or the color of the particle
GRBAlpha: The smallest astrophysical space observatory
Aims. Since it launched on 22 March 2021, the 1U-sized CubeSat GRBAlpha operates and collects scientific data on high-energy transients, making it the smallest astrophysical space observatory to date. GRBAlpha is an in-orbit demonstration of a gamma-ray burst (GRB) detector concept suitably small to fit into a standard 1U volume. As was demonstrated in a companion paper, GRBAlpha adds significant value to the scientific community with accurate characterization of bright GRBs, including the recent outstanding event of GRB 221009A.
Methods. The GRB detector is a 75 × 75 × 5 mm CsI(Tl) scintillator wrapped in a reflective foil (ESR) read out by an array of SiPM detectors, multi-pixel photon counters by Hamamatsu, driven by two separate redundant units. To further protect the scintillator block from sunlight and protect the SiPM detectors from particle radiation, we applied a multi-layer structure of Tedlar wrapping, anodized aluminium casing, and a lead-alloy shielding on one edge of the assembly. The setup allows observations of gamma radiation within the energy range of 70–890 keV with an energy resolution of ~30%.
Results. Here, we summarize the system design of the GRBAlpha mission, including the electronics and software components of the detector, some aspects of the platform, and the current semi-autonomous operations. In addition, details are given about the raw data products and telemetry in order to encourage the community to expand the receiver network for our initiatives with GRBAlpha and related experiments