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1

Influence of particle breakage on bulk density of dynamically compacted coarse aggregates

Brzeziński Karol, Maślakowski Maciej, Józefiak Kazimierz

Roads and Bridges - Drogi i Mosty

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2024

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Vol. 23, no. 2

179--201

EN

The article presents the first discrete element method (DEM) simulations of dynamic compaction in the Proctor test. The aim of the simulations was to analyze the influence of particle breakage on the density of intensely compacted granular assembly. Results from simulations and laboratory tests were compared. Simulations with non-breakable aggregates enabled separation of the influence of change in particle size distribution and particle rearrangement. Both factors play an essential role in increasing the bulk density of the sample in the case of the tested (gap-graded) aggregate. Simulations with breakable particles reproduce the laboratory tests results better, both qualitatively and quantitatively. The conclusions provide a better understanding of the aggregate compaction process, which is crucial for developing novel compaction strategies and minimizing the environmental impact of the construction process.

PL

W artykule przedstawiono pierwszą przeprowadzoną metodą elementów dyskretnych (DEM) symulację dynamicznego zagęszczania w badaniu Proctora. Celem wykonanych symulacji było znalezienie odpowiedzi na pytanie, w jaki sposób, w jaki sposób pękanie ziaren wpływa na gęstość intensywnie zagęszczanej próbki materiału ziarnistego. Porównano wyniki symulacji i badań laboratoryjnych. Symulacje z ziarnami niełamliwymi pozwoliły na wyodrębnienie wpływu zmiany rozkładu wielkości ziaren i wzajemnego ich przemieszczania. Obydwa czynniki odgrywają zasadniczą rolę w zwiększaniu gęstości objętościowej próbki w przypadku badanego kruszywa o nieciągłym uziarnieniu. Symulacje z ziarnami łamliwymi lepiej odtwarzają badanie laboratoryjne pod względem jakościowym i ilościowym. Wnioski pozwalają na lepsze zrozumienie procesu zagęszczania kruszywa, co ma kluczowe znaczenie dla opracowania nowatorskich strategii zagęszczania i minimalizacji wpływu procesów budowlanych na środowisko.

2

Use of DEM to characterize damage of delicate fruit on feeders with reciprocating drive

Olejnik Tomasz P., Sobiecka Elżbieta, Kryszak Dariusz

Technologia i Jakość Wyrobów

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2023

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R. 68

171--186

EN

This article describes the modeling by DEM technology of damage to highbush blueberries, during transport on a reciprocating feeder. The modeled values of normal and tangential forces at the blueberry contact points were determined, and the effect of changing the mass output of the transported fruit on the values of normal and tangential forces was studied. It has been shown that the change in the mass output of blueberries does not exceed the permissible tangential and normal forces, interacting between the fruits.

PL

W artykule opisano modelowanie technologią DEM uszkodzeń borówki wysokiej, podczas transportu na podajniku z napędem posuwisto-zwrotnym. Określono modelowe wartości sił normalnych oraz stycznych w punktach kontaktu borówki. Przeprowadzono symulacje uwzględniające wpływ zmiany wydatku masowego transportowanych owoców na wartości sił normalnych i stycznych. Wykazano, że zmiana wydatku masowego borówki nie powoduje przekroczenia dopuszczalnych sił stycznych i normalnych, oddziałujących pomiędzy owocami.

3

Possibilities and limitations of using iPhone 13 Pro with built-in LiDAR sensor in cave research – on the example of paleoflow analysis in Mylna Cave (Western Tatra Mts, Poland)

Pluta Przemysław, Siemek Dawid

Landform Analysis

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2023

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Vol. 42

51--62

EN

The study tested the capabilities of the Apple iPhone 13 Pro device using two measurement techniques, LiDAR (Light Detection and Ranging) and SfM (Structure from Motion), in a cave environment by measuring scallops in Mylna Cave in Western Tatra Mountains. The tested device provides an interesting and inexpensive alternative for cave research using TLS (Terrestrial Land Scanner) type scanners or more expensive MLS (Mobile Laser Scanning) type scanners. The study used a dedicated 3D Scanner App™ application to create two terrain models: LiDAR and SfM. A comparative analysis of the models shows that the SfM model is characterised by greater detail. The results obtained for this model indicate that the scallops measured in Wielki Chodnik passage of Mylna Cave belong to at least two different generations of forms. In the LiDAR method case, the obtained models’ resolution was not precise enough to identify small (<3 cm) scallops. For three LiDAR models, the average length of scallops was 10.32 cm; for three SfM models, it was 5.16 cm. The length of scallops obtained from models allowed for calculating paleoflow velocity and, thus, the flow rate. The average velocity value for LiDAR models was 28.98 cm s−1, and for SfM models – 48.10 cm s−1 and the average flow rate obtained from SfM data was 1.93 m³ s−1. It corresponds well with the today-observed Kościeliski Potok flow rate of 1.7 m³ s−1 according to the 1966–2000 period (Baścik et al. 2014). On the contrary, the average paleoflow rate obtained from the LiDAR model, which is 0.94 m³ s−1, does not match the contemporary flow rate. Based on the asymmetry of scallops, the paleoflow direction was determined. It is consistent with the current direction of the Kościeliski Potok flow. The spatial imaging techniques used with iPhone 13 Pro differ regarding the DEM creation method and model details. It is influenced by parameters related to lighting, distance, scanned surface character and microclimatic conditions of the cave.

4

Research on optimal design of vibration reduction of centrifugal air conditioning chiller based on particle damping

Xiao Wangqiang, Shi Jinsong, Chen Hui, Liu Hua

Journal of Theoretical and Applied Mechanics

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2023

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Vol. 61 nr 1

189--201

EN

Considering vibration of centrifugal air-conditioning chillers at working conditions of 300Hz and 386Hz, a vibration reduction method for centrifugal air-conditioning chillers based on particle damping is proposed. Firstly, the vibration transfer path of the chillers is determined based on dynamic characteristics analysis of the chillers. Secondly, the vibration sensitive area of the compressor is determined by finite element analysis. Then the energy dissipation is calculated by the discrete element method (DEM) to determine the optimal installation scheme of the damper. Finally, the vibration reduction effect of the chillers after arranging the damper is verified by experiments.

5

Runoff Estimation for the Central Region of the Lesser Zab River Watershed Using the SCS-Curve Number Method and GIS

Salman Qasim Mohammed Khudair, Hamdan Ahmed Naseh Ahmed

Journal of Ecological Engineering

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2023

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Vol. 24, nr 9

232--245

EN

This study aimed to develop a hydrologic model for the central region (central catchments) located between Dokan and Al-Dibis dams in the Lesser Zab River (LZR) watershed, in Iraq. The hydrologic structure of the study area was prepared based on the DEM layer with 12.5 m spatial resolution by using the GIS environment, and then the HEC-HMS software was used for simulating the main hydrological processes like the infiltration losses, transformation, channel routing, and the baseflow contribution by using the SCS-CN, SCS-UH, Muskingum, and the Recession methods respectively. The corrections of the CN parameter due to the effects of the slope and initial abstraction were used and the resulting CN values for the entire LZR watershed were ranging from 56 to 100. This study concluded the effectivity of using the GIS environment and HEC-HMS software in the continuous rainfall-runoff modelling and achieved very good performance with R2 and NSE criteria of 0.9115 and 0.9 under the calibration phase, while 0.925 and 0.91 values were achieved for the same criteria under the validation phase respectively, also the CN was the most sensitive parameter in the proposed hydrologic model.

6

The numerical techniques application in the ball mill comminution process modelling

Pawlos Witold, Dominiczak Przemysław

Cuprum : czasopismo naukowo-techniczne górnictwa rud

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2023

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nr 1-2

47--53

EN

The preliminary results of comminution process numerical simulations have been presented in this paper. The numerical prediction has been based on discrete elements method (DEM) for solid modelling and smoothed particles hydrodynamics method (SPH) for modelling a continuous medium – liquid. The one way numerical coupling between solid and liquid has been applied. The ball mill working in production line in O/ZWR has been modelled. The considered ball mill is used to copper ore comminution process. The numerical calculations have been carried out for different mill rotation speed.

PL

W artykule przedstawiono wstępne wyniki numerycznych symulacji procesu rozdrabniania. Prognozowanie numeryczne zostało oparte na metodzie elementów dyskretnych (DEM), wykorzystanej dla modelowania cząstek stałych, oraz na metodzie symulacji hydrodynamicznej (SPH) dla modelowania w ośrodku ciągłym – ciecz. Zastosowano jednokierunkowe sprzężenie numeryczne pomiędzy fazą stałą a ciekłą. Młyn kulowy, zainstalowany w ciągu technologicznym ZWR, został wytypowany jako obiekt modelowania. Rozpatrywany młyn pracuje jako urządzenie rozdrabniające rudę miedzi. Obliczenia numeryczne przeprowadzono dla różnych prędkości obrotowych młyna.

7

Sensitivity analysis of the dem model numerical parameters on the value of the angle of repose of lunar regolith analogs

Młynarczyk Przemysław, Kolusz Adam, Gallina Alberto

Artificial Satellites : Journal of Planetary Geodesy

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2023

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Vol. 58, Special Issue 1

188--202

EN

The discrete element method (DEM) is a numerical technique used in many areas of modern science to describe the behavior of bulk materials. Terramechanics of planetary soil analogs for in situ resource utilization activities is a research field where the use of DEM appears to be beneficial. Indeed, the close-to-physics modeling approach of DEM allows the researcher to gain much insight into the mechanical behavior of the regolith when it interacts with external devices in conditions that are hard to test experimentally. Nevertheless, DEM models are very difficult to calibrate due to their high complexity. In this paper, we study the influence of fundamental model parameters on specific simulation outcomes. We provide qualitative and quantitative assessments of the influence of DEM model parameters on the simulated repose angle and computational time. These results help to understand the behavior of the numerical model and are useful in the model calibration process.

8

Comparison of depression removal methods implemented in open-source software

Šamanović Sanja, Markovinović Danko, Cetl Vlado, Đurin Bojan

GIS Odyssey Journal

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2022

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Vol. 2, no. 1

85--97

EN

Modern tools for hydrological analysis are based on data derived from DEM. Hydrological methods that create a stream network by overland flow simulation require to remove depression (pit or sink) on DEM first. Depression occurs when a cell or group of cells is surrounded by adjacent cells at higher altitudes. Even though their removal creates an incorrect DEM, it is common practice to remove all topographic depressions (real, artificial, or combined) not to interrupt the creation of stream networks. There are two basic methods of depression removal: the filling method and the carving or breaching. Combined methods contain good characteristics of both procedures. GIS software includes a depression removal algorithm within its hydrological analysis module. The paper investigates which methods are implemented within individual open-source software SAGA and GRASS. A comparison of DEM before and after depression removal for each method is given. The methods were tested on a DEM, resolution 5x5 meter for a hilly area intersected by a significant number of watercourses.

9

Flood Frequency Analysis and Hydraulic Design of Bridge at Mashan on River Kunhar

Riaz Khuram, Aslam Hafiz Muhammad Shahzad, Yaseen Muhammad Waseem, Ahmad Hafiz Haseeb, Khoshkonesh Alireza, Noshin Sadaf

Archives of Hydro-Engineering and Environmental Mechanics

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2022

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Vol. 69, nr 1

1--12

EN

Kunhar River hydrology and hydraulic design of a bridge on this river are being studied using HEC-Geo-RAS and Hydrologic Engineering Centers River Analysis System (HEC-RAS). The river flows in the northern part of Pakistan and is 170 km long. On both sides of the river, there are residential settlements. The river hydraulics is studied by using 30-metre remotely sensed shuttle radar topographic mission - digital elevation model (SRTM DEM) and Arc Map. 32 cross-sections are imported from Geographic Information System (GIS) to HEC-RAS. On historical peak flow results, the extreme value frequency distribution is applied, and a flood is determined for a 100-year return period, with a discharge estimated as 2223 cubic metres. Three steady flow profiles are adopted for HEC-RAS, the first is for the maximum historical peak data, the second is for the 100-year return period, and the third profile is for the latter 100-year period with a safety factor of 1.28. With remote sensing-based assessments, the proposed location for a bridge is determined and then verified with a field survey which was physically conducted. The maximum water height estimated in the river is about 4.26 m. This bridge will facilitate about 50 thousand population of Masahan and its surroundings. It will create a shortest link between Khyber Pakhtunkhwa and Azad Kashmir and thus will enhance tourism and trade activities.

10

Calibration of Selected Bulk Biomaterials Parameters for DEM Simulation of Comminution Process. Case Study: Corn and Rice Grains

Kruszelnicka Weronika, Diviš Jan, Hlosta Jakub, Gierz Łukasz, Žurovec David

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 5

64--77

EN

Computer simulation of bulk materials behavior, including comminution and fragmentation, using DEM has been growing fast, recently. One of the important tasks to get the reliable simulation results is to provide proper materials and contact parameters, which need to be determined in a series of laboratory experiments. For comminution simulation the additional parameters describing the breakage probability and breakage functions are necessary. While some simulation parameters are available in the literature for brittle materials, valid data are lacking for biomaterials such as cereal, rice or corn grains, especially for comminution parameters. The aim of this study was to present the calibration approach and determination of materials, contact, interaction and breakage parameters for grainy biomaterials. The calibration process was done for rice and corn grains. The calibration approach consists of grains size distribution and shape characterization, friction and restitution coefficient determination, and breakage probability description. Based on the results of the experiments, the models were created in the DEM software. The result was the set of calibrated parameters for rice and corn grains.

11

Assessment of spatiotemporal changes of the length and starting date seasons in the west of Iran

Nazripouya Hadi, Meshram Sarita Gajbhiye, Bahramloo Reza, Sepehri Mehdi, Ali Sk Ajim, Kushwaha Nand Lal, Kiani Harchegani Mahboobeh, Rodrigo-Comino Jesús

Acta Geophysica

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2022

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Vol. 70, no 6

2813--2825

EN

There is evidence that human activities are affecting global dynamics. The consequences of changes in the duration of the annual seasons and daily temperatures will imply drastic impacts on human and natural ecosystems. However, estimations related to the duration of the seasons considering the daily temperatures are scarce and could help to foresee negative effects with irreparable consequences. This study investigates the spatiotemporal variation of length and start date of each annual season based on temperature criteria by analyzing daily data of synoptic stations in western Iran from the period 1977–2015. Our results demonstrated that the starting date of summer shows a tendency advanced and the starting date of winter has been delayed. Moreover, spring is coming earlier. On the other hand, winter ends earlier and fall is delayed, with longer summers and shorter winters as a result. The starting date of summer differs from 0 to 2 d advanced in the southwest of the study area and 4–6 d advanced in the central and southeast parts. The starting date of winter on average has been delayed by 2 days and the length of the season has been shortened by 5 days. The changes for spring and fall are relatively smaller. Particularly, spring started earlier by 4.2 days but was extended by 1.8 days, and the fall season has started delayed by 0.8 days but extended by 0.4 days. This study provides simple information to stakeholders and policymakers so that they should focus on the issue and start developing efficient plans to reduce the negative impacts on the temperatures, shorter winters and the earlier spring, which could affect the floriation and animal behaviors among others.

12

The study of local terrain modeling methods for vertical planning of the territory

Trevoho Ihor, Ostrovskiy Apollinariy, Kolb Ihor, Ostrovska Olena, Zhyvchuk Viacheslav

Geodesy and Cartography

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2021

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Vol. 70, no. 2

art. no. e09

EN

This work aims to study the vertical planning method for the terrain area as part of the process of construction geodetic support. Such planning will be carried out based on the aerial survey data from UAVs, which allow the creation of a high-quality digital elevation model (DEM) with sufficient node density for reliable surface terrain modelling. During the study, we test the hypothesis of the possibility of using archival aerial photographs from UAVs to model the terrain of the local area. Both the actual achievable accuracy of terrain modeling in the course of photogrammetric processing of archived aerial photographs, and methods for creating a polygonal terrain model using input spatial data in the form of clouds of 3D points of a given density require analysis. To do this, we will perform comparisons of the accuracy of calculating earth masses, carried out based on the digital triangulation elevation models (TIN). These models were based on different algorithms for creating Delaunay triangulation with different degrees of 3D point sparsity.We proposed to use sparsity of dense clouds of points representing the surface of the terrain and which were obtained by the photogrammetric method. Computer terrain modelling and calculation of vertical planning parameters were performed by us for the area with flat terrain at angles up to 3.5 degrees. We evaluated the potential of archived UAV aerial photographs and algorithms for creating Delaunay triangulation at different densities of its nodes for calculating the volumes of earth masses.

13

Studies on Moisture Effects on Powder Flow and Mechanochemical Improvement of Powder Flowability

Opaliński Ireneusz, Chutkowski Marcin, Stasiak Mateusz, Leś Karolina, Olechowski Marcin, Przywara Mateusz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 2

228--246

EN

Recent findings on some unsolved powder rheology problems and new challenges regarding mechanochemical powder processing and flow modelling are presented. There is remarkable difference in rheology when processing moist powders in static or dynamic conditions. Despite of regular trends of shear stress changes with humidity found in the both cases, some exceptions revealed the significant impact of particles size and their hygroscopic nature as example. Mechanochemical methods of high-energy interactive mixing of highly cohesive powders doped with nano-sized solid admixture enabled their flowability to be improved considerably. Using statistical approach, more general routine is proposed that allow the optimal mixing parameters to be reliably predicted with limited number of experiments needed. Ability to flow of some hygroscopic powders was examined with DEM method and extreme sensitivity of model output to input particle properties was found. The common DEM routine towards powder flow prediction is therefore suggested to be replaced with approach featuring in using DEM method to identify some unknown powder flow factors.

14

Evaluation of Impact of Land Use in Adjacent Areas Causing Damage to Dirt Roads Using GIS Tools - Case Study

Fiedler Michał, Stachowski Piotr

Rocznik Ochrona Środowiska

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2020

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Tom 22, cz. 1

281--293

EN

Surface run-off from areas adjacent to dirt roads may cause considerable damage to these roads. The degree of damage is determined from the amount of flowing water, run-off intensity as well as sites, in which run-off reaches the roads. These parameters result from soil conditions, as well as natural relief and the land form modified by tillage operations. Another parameter influencing the formation and the degree of erosion is connected with maintenance operations regularly repeated in the life cycle of these roads, such as e.g. surface levelling or use of paving materials. The analysis involved GIS tools, which made it possible to consider the impact of spatial variability in the surroundings of such roads on the incidence of adverse factors. The application of LiDAR data made it possible to indicate the formation of surface run-off routes and the resulting threats of damage to dirt roads.

PL

Spływy powierzchniowe z terenów przyległych do dróg gruntowych mogą wywoływać znaczne uszkodzenia tych dróg. Stopień uszkodzeń wynika z ilości spływającej wody, intensywności spływu oraz miejsc, w których spływy docierają do dróg. Parametry te wynikają z warunków glebowych oraz naturalnego i wynikającego ze stosowanych zabiegów uprawowych ukształtowania powierzchni terenu. Kolejnym parametrem wpływającym na powstawanie i stopień erozji są cykliczne zabiegi konserwacyjne stosowane w procesie utrzymania tych dróg, jak np. wyrównywanie powierzchni czy stosowanie materiałów utwardzających. W analizie zagadnienia zastosowano narzędzia GIS pozwalające na uwzględnienie wpływu przestrzennej zmienności otoczenia takich dróg na występowanie czynników szkodliwych. Wykorzystanie danych LIDAR pozwoliło na wskazanie ścieżek formowania się spływów powierzchniowych i wynikających z nich zagrożeń uszkodzeniami dróg gruntowych.

15

Flight Height of UAV and Its Influence on the Precise Digital Elevation Model at Complex Terrain

Nguyen Quoc Long, Goyal Ropesh, Le Van Canh, Cao Xuan Cuong, Pham Van Chung, Bui Ngoc Quy, Bui Xuan Nam, Bui Khac Luyen

Inżynieria Mineralna

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2020

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no. 1, vol. 1

179--186

EN

The application of lightweight Unmanned Aerial Vehicle (UAV) has been increasingly common in 3D topographic surveys. Especially in the complex terrains such as open-pit mines, where the elevation is rapidly undulating, the UAV based mapping is more efficient, economic and safe compared to the conventional methods. However, one of the most important factors in UAV mapping of complex terrain is the flight altitude which needs to be seriously considered because of the safety and accuracy of generated DEMs. This paper aims to evaluate the influence of flight height on accuracy of DEMs generated for open-pit mines. For this purpose, the selected study area is a quarry with complex terrain located in the Northern Vietnam. The investigation was conducted with five flight heights of 50 m, 100 m, 150 m, 200 m, and 250 m. To assess the accuracy of resulting DEMs, 10 ground control points and 385 checkpoints measured by both GNSS/RTK and total station methods were used. The accuracy of DEM was assessed by using root-mean-square error (RMSE) in X, Y, Z, XY, and XYZ components. The result showed that the DEM models generated at the flight heights of less than 150 m have high accuracy, RMSEs on the 10 GCPs increased from 1.8 cm to 6.2 cm for vertical (Z), and from 2.6 cm to 6.3 cm for horizontal (XY), whereas RMSE on 385 checkpoints increases gradually from 0.05 m to 0.15 m for vertical (Z) when the height flight increased from 50 m to 250 m.

PL

Zastosowanie lekkich bezzałogowych statków powietrznych (UAV) jest coraz bardziej powszechne w badaniach topograficznych 3D. Zwłaszcza w skomplikowanych terenach, takich jak kopalnie odkrywkowe, w których wzniesienie gwałtownie faluje, mapowanie oparte na UAV jest bardziej wydajne, ekonomiczne i bezpieczne w porównaniu z metodami konwencjonalnymi. Jednak jednym z najważniejszych czynników w mapowaniu UAV złożonego terenu jest wysokość lotu, którą należy poważnie rozważyć ze względu na bezpieczeństwo i dokładność generowanych DEM. Niniejszy artykuł ma na celu ocenę wpływu wysokości lotu na dokładność DEM generowanych dla kopalni odkrywkowych. W tym celu wybranym obszarem badawczym jest kamieniołom o złożonym terenie położony w północnym Wietnamie. Badanie przeprowadzono przy pięciu wysokościach lotu 50 m, 100 m, 150 m, 200 m i 250 m. Aby ocenić dokładność uzyskanych DEM, wykorzystano 10 naziemnych punktów kontrolnych i 385 punktów kontrolnych mierzonych zarówno metodami GNSS/RTK, jak i metodami stacji całkowitej. Dokładność DEM oceniono za pomocą błędu pierwiastkowego średniego kwadratu (RMSE) w komponentach X, Y, Z, XY i XYZ. Wynik pokazał, że modele DEM generowane na wysokościach lotu poniżej 150 m mają wysoką dokładność, RMSE na 10 GCP wzrosły z 1,8 cm do 6,2 cm dla pionu (Z) i od 2,6 cm do 6,3 cm dla poziomu (XY), podczas gdy RMSE na 385 punktach kontrolnych wzrasta stopniowo z 0,05 m do 0,15 m dla pionu (Z), gdy lot na wysokości wzrósł z 50 m do 250 m.

16

Modelowanie i analiza płynięcia materiału rozdrobnionego podczas ścinania w reometrze pierścieniowym z wykorzystaniem metody elementów dyskretnych

Chutkowski Marcin, Zapała Wojciech, Przywara Mateusz

Chemical Technology & Biotechnology

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2020

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Vol. 2

52--60

PL

Ze względu na fakt, że komórka Jenike’go została zaprojektowana i jest stosowana do testów materiałów proszkowych pod obciążeniem rzędu setek kPa, charakterystycznych dla procesów wielkotonażowych, jest nieodpowiednim narzędziem do badań materiałów w warunkach obciążeń znacznie poniżej 10 kPa. Ponadto, konstrukcja komórki Jenike’go sprawia, że ścinaniu poddawany jest wąski obszar testowanej próbki, podczas gdy większość materiału pozostaje nieruchoma. Jako alternatywę zaproponowano badanie w szczelinowym reometrze pierścieniowym, skonstruowanym w taki sposób, że pasmo ścinania obejmuje całą objętość testowanego materiału. Po przeprowadzonych badaniach eksperymentalnych zastosowano symulację komputerową ścinania proszku, opartą na metodzie DEM, do przeanalizowania rozkładów czasowo-przestrzennych niemierzalnych eksperymentalnie właściwości fizycznych złoża. Wyniki symulacji stanowią podstawę wniosku o pasmie ścinania wypełniającym całą szczelinę reometru.

EN

Due to the fact that Jenike's cell has been designed and used for testing powder materials under load of hundreds of kPa, characteristic for large-tonnage processes, it is an in appropriate tool for testing materials under load conditions well below 10 kPa. As an alternative, an annular cell rheometer test constructed in such a way that the shear band covers the entire volume of material tested is proposed. After the experimental tests, a computer simulation of powder shearing, based on the Discrete Element Method (DEM), was used to analyze time-spatial distributions of experimentally unmeasurable physical properties of the powder bed. The simulation results proved that the shearing band cover sentire rheometer gap.

17

Efficiency of using GNSS-PPP for digital elevation model (DEM) production

Abdallah Ashraf, Saifeldin Amgad, Abomariam Abdelhamid, Ali Reda

Artificial Satellites : Journal of Planetary Geodesy

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2020

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Vol. 55, No. 1

17--28

EN

In the developing countries, cost-effective observation techniques are very important for earthwork estimation, map production, geographic information systems, and hydrographic surveying. One of the most cost-effective techniques is Precise Point Positioning (PPP); it is a Global Navigation Satellite Systems (GNSS) positioning technique to compute precise positions using only a single GNSS receiver. This study aims to evaluate the efficiency of using Global Positioning System (GPS) and GPS/ Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS) post-processed kinematic PPP solution for digital elevation model (DEM) production, which is used in earthwork estimation. For this purpose, a kinematic trajectory has been observed in New Aswan City in an open sky area using dual-frequency GNSS receivers. The results showed that, in case of using GPS/GLONASS PPP solution to estimate volumes, the error in earthwork volume estimation varies between 0.07% and 0.16% according to gridding level. On the other hand, the error in volume estimation from GPS PPP solution varies between 0.40% and 0.99%.

18

Badania symulacyjne w projektowaniu głowicy dyskowej nowej generacji

Stopka Grzegorz

Systemy Wspomagania w Inżynierii Produkcji

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2019

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Vol. 8, iss. 1

164--172

PL

W artykule przedstawiono koncepcję głowicy dyskowej nowej generacji oraz dotychczasowy zakres badań stanowiskowych związany z jej doświadczalną weryfikacją. Przedstawiono podstawowe zagadnienia będące przedmiotem aktualnych badań modelowych związanych z rozwojem konstrukcji głowicy, w tym modelowaniem dynamiki układu napędowego oraz symulacją obciążeń narzędzi dyskowych.

EN

he article presents a concept of the new generation mining head with disc tools and current scope of research related to experimenal verification. In the article the basic issues that are the subject of current simulation modeling are presented related to the development of the head construction, including modeling of dynamics of power transmission system and the simulation of disk tool loads.

19

The height survey of mount Łysica in the context of verification of geodesical and cartographic studies

Romanyshyn Ihor, Hajdukiewicz Maciej

Structure and Environment

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2019

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Vol. 11, no. 2

153--164

EN

The subject of the article is the measurements of normal height (H) of the western top of Mount Łysica (Świętokrzyskie Mountains, Poland), carried out using the GNSS and geometric leveling methods according to standards for geodetic control network. As the elevation system EN-KRON86-NH was assumed. The reference data was the result of earlier measurements made using different methods: ALS, GNSS RTN and geometric levelling between selected points of Mount Łysica. The analysis of the survey results showed differences between the DEM from ALS measurement and the actual height reaching up to 0.47 m on small boulders and not exceeding the value of 0.17 m in the flat area. Differences between GNSS RTN measurement and geometric leveling based on GNSS static measurement did not exceed 0.03 m. An inventory of former state geodetic control network point “12 Góra Łysica” was also conducted. The point was found to be partially destroyed, and located 12 m south and 1.5 m below the actual top of the mountain. Therefore it was assumed, that a new geodetic control network point should be located on the top for the needs of forest inventory as well as setting the actual height of Mount Łysica.

PL

W artykule opisano wyniki pomiarów wysokości normalnej H wybranych punktów na wierzchołku zachodnim góry Łysicy w paśmie Łysogór (Góry Świętokrzyskie), przeprowadzone metodami GNSS i niwelacji geometrycznej według standardów dla osnowy wysokościowej. Jako układ wysokościowy przyjęto PL-KRON86-NH, a wyniki zestawiono z wcześniejszymi pomiarami ALS, GNSS RTN i niwelacją geometryczną między wybranymi punktami wysokościowymi na masywie Łysicy. Analiza wyników pomiarów wykazała rozbieżności pomiędzy modelem terenu z pomiaru ALS a wysokością rzeczywistą osiągające wartości do 0,47 m na niewielkich wypukłych formach terenu i nieprzekraczające wartości 0,17 m na terenie płaskim. Rozbieżności pomiędzy pomiarem GNSS RTN a niwelacją geometryczną w oparciu o pomiar GNSS static nie przekraczały wartości 0,03 m. Przeprowadzono również inwentaryzację stanu starego punktu osnowy geodezyjnej 12 góra Łysica. Wobec faktu, że punkt ten jest częściowo zniszczony i znajduje się w odległości 12 m w poziomie i 1,5 m poniżej rzeczywistego wierzchołka, zasadne wydaje się założenie nowego punktu osnowy, który służyłby m.in. pomiarom w ramach inwentaryzacji stanu lasu, a także wyznaczał rzeczywistą wysokość szczytu Łysicy.

20

Comparison of the Resampling Methods for Gridded DEM Downscaling

Nguyen Quang Minh, Nguyen Thi Thu Huong, La Phu Hien, Duong Thi Tuyet Nhung, Nguyen Thi Minh Hong, Vu Van Anh

Inżynieria Mineralna

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2019

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R. 21, nr 2/2

240--248

EN

In this paper, a comparison and evaluation of three resampling methods for gridded DEM is implemented. The evaluation was based on the results of bilinear resampling, bi-cubic and Kriging resampling methods for an experiment using both degraded and sampled datasets at 20 m and 60 m spatial resolutions. The evaluation of the algorithms was accomplished comprehensively with visual and quantitative assessments. The visual assessment process was based on direct comparison of the same topographic features in different downscaled images, scatterplots and profiles. The quantitative assessment was based on the most commonly used parameters for DEM accuracy assessment such as root mean square errors (RMSEs), linear regression parameters m and b, and correlation coefficient R. Both visual and quantitative assessment revealed greater accuracy of the Kriging over the other two conventional methods.