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Tytuł:
The relationships between the kinetic grinding parameters with interstitial fillings and the liberation degree of a chromite ore
Autorzy:
Umucu, Yakup
Deniz, Vedat
Gursoy, Hakan Y.
Tokcan, Isıl
Arsoy, Zeyni
Powiązania:
https://bibliotekanauki.pl/articles/24148630.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
grinding
ball mill
kinetic model
liberation degree
interstitial filling
Opis:
In this study, the relationships between the liberation degree and the kinetic breakage parameters of a chromite ore obtained from the Burdur (Türkiye) were examined under the laboratory conditions. Firstly, liberation degrees for chromite particles were determined by the particle counting method in a metal microscope for 4 different size groups. Secondly, the breakage parameter of chromite ore which was dry ground with a ball mill was obtained using standard test methods. Additionally, the model parameters were also determined for the fractional interstitial fillings (U) of the chromite sample. Thirdly, the kinetic grinding parameters were compared with the liberation degree of the chromite sample. As a result of the tests, a very good correlation was obtained with R2=0.998, and regression analysis in the grinding processing of the chromite ore was used to verify the validity of the relationship parameter of Si that was produced. To these, it was found that interstitial fillings (U=0.6, 0.8, 1.0, and 1.2) have an effect on the grinding.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 5; art. no. 168254
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of depression removal methods implemented in open-source software
Autorzy:
Šamanović, Sanja
Markovinović, Danko
Cetl, Vlado
Đurin, Bojan
Powiązania:
https://bibliotekanauki.pl/articles/2191402.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie SILGIS
Tematy:
DEM
depression removal
open-source software
stream network
filling method
carving method
usuwanie depresji
oprogramowanie open source
sieć rzeczna
metoda wypełniania
metoda rzeźbienia
Opis:
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.
Źródło:
GIS Odyssey Journal; 2022, 2, 1; 85--97
2720-2682
Pojawia się w:
GIS Odyssey Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of three control algorithms for an averaging tank with variable filling
Autorzy:
Kolankowski, Michał
Piotrowski, Robert
Powiązania:
https://bibliotekanauki.pl/articles/2105996.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
control system
fuzzy control system
integral control system
LQR
mathematical model
PID control system
state feedback controller
tank with variable filling
Opis:
An averaging tank with variable filling is a nonlinear multidimensional system and can thus be considered a complex control system. General control objectives of such object include ensuring stability, zero steady-state error, and achieving simultaneously shortest possible settling time and minimal overshoot. The main purpose of this research work was the modeling and synthesis of three control systems for an averaging tank. In order to achieve the intended purpose, in the first step, a mathematical model of the control system was derived. The model was adapted to the form required to design two out of three planned control systems by linearization and reduction of its dimensions, resulting in two system variants. A multivariable proportional-integral-derivative (PID) control system for the averaging tank was developed using optimization for tuning PID controllers. State feedback and output feedback with an integral action control system for the considered control system was designed using a linear-quadratic regulator (LQR) and optimization of weights. A fuzzy control system was designed using the Mamdani inference system. The developed control systems were tested using theMATLAB environment. Finally, the simulation results for each control algorithm (and their variants) were compared and their performance was assessed, as well as the effects of optimization in the case of PID and integral control (IC) systems.
Źródło:
Acta Mechanica et Automatica; 2022, 16, 2; 136--150
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plastic filling simulation comparison analysis of the gating system in injection moulding parameter
Autorzy:
Umor, M. Z.
Mohd, A.
Efendee, A. M.
Khir, M.
Bahiyah Baba, N.
Powiązania:
https://bibliotekanauki.pl/articles/2201029.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
filling simulation
gating system
moulding parameters
symulacja
system bramkowania
parametry wtrysku
Opis:
Purpose: The paper is discussed the anticipation of the simulation software precision with the real moulding process by setting up the distinctive metering stroke separation. Design/methodology/approach: The Inventor CAD software was used to design the product experiment and perform the simulation by applying MoldFlow application to produce the processing parameter defining for the injection moulding machines. Findings: The results predicted by this filling simulation appears reasonable result as compared to the injected product. Prediction analysis given by the software is exceptionally valuable for the injection moulding parameter setting machines which can diminish the time of mould setup and can reduce the trial stage on the production line. Research limitations/implications: The gating system is the most crucial part in injection moulding process and the limitation is to get the accurate filling time and injection pressure to ensure the cavity is fully filled before the material at the gate solidify. Originality/value: Gating system configurations are utilized to optimize the filling conditions of injection moulding parts. This important element was developed for achieving product quality. The utilize of simulation software is exceptionally supportive in the model designing stage to predict the quality and process capacity for the product. This paper presents the filling simulation of the side gate system to the injection moulding parameter.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 112, 2; 64--69
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on stability of self-compacting concrete applied for filling layer structure from paste, mortar and concrete
Autorzy:
Liu, He
Zhang, Jingyi
Yang, Yanhai
Powiązania:
https://bibliotekanauki.pl/articles/2174048.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stabilność
beton samozagęszczalny
warstwa wypełniająca
lepkość plastyczna
proporcja mieszanki
stability
self-compacting concrete
filling layer
plastic viscosity
mix proportion
Opis:
Self compacting concrete (SCC) filling layer is core structure of China rail track system (CRTS) ? type ballastless track. Construction quality, service performance and durability of CRTS ? ballastless structure are affected by stability of SCC for filling layer. In this study, the stability of SCC of filling layer is researched at three levels as paste, mortar and concrete by theory and experiment. Evaluation indices including bleeding (B), surface bubble rate (θ), thickness of paste (paste) and thickness of surface mortar (L) are proposed based on the theoretical calculation and analysis. The threshold viscosity of paste 0.394 Pa·s and mixture satisfied area are obtained at paste level based on the relationship between viscosity and B, θ of paste. The mixture satisfied area was defined at mortar level under criterions of maximum value of paste and slump flow. Optimal range of gap between neighboring aggregates (λca) 12.4 mm-14.1 mm is chosen by flow ability, passing ability, stable ability of SCC. These research results will help to further understand the stability of SCC.
Źródło:
Archives of Civil Engineering; 2022, 68, 3; 501--522
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of the main component ratios in the joint filling on the product quality
Autorzy:
Rizaoğlu, Tamer
Karataş, Muhammed Ziya
Çoşkun, Canberk
Powiązania:
https://bibliotekanauki.pl/articles/27324350.pdf
Data publikacji:
2022
Wydawca:
Instytut Techniki Górniczej KOMAG
Tematy:
cement
joint filling
calcite
building materials
Opis:
When building materials are exposed to environmental and natural factors such as temperature differences, humidity, strong wind and earthquake in the areas where they are applied, irreversible damages such as separation, cracking and level difference occur in structures and building materials. In order to prevent these damages, the joints are left between the building materials and the gaps are filled with filling materials. The composition of the materials filling the joint gaps is also very important. The most important problems encountered in joint fillings are rupture, cracking and therefore permeability. In this study, it is aimed to compare the joint filling materials produced from different proportions of aggregate and white cement against rupture and cracking, and to determine the mixture ratio that exhibits the best performance. Five different recipes were prepared by using calcite powder as aggregate, white Portland cement as binder and water-repellent, volumizing and thickening chemical additives as auxiliary materials. On the prepared test samples; Capillary water absorption, water absorption by weight and volume, unit volume weight, saturated unit volume weight, porosity, compressive strength, bending strength, surface hardness and abrasion resistance tests were carried out. Considering the cost and environmental damage of cement, which is one of the main components in joint filler material, DD2 [Calcite (71.50%)] + White Cement (26.50%) + [Polymer + Cellulose + Plasticizer + Silicone] 2% has been detected as the most appropriate recipe.
Źródło:
Mining Machines; 2022, 40, 4; 180--190
2719-3306
Pojawia się w:
Mining Machines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis and application of filling mining technology in China’s mining area: a case study of Yuxing Coal Mine
Autorzy:
Huang, Dongmei
Xing, Daqian
Chang, Xikun
Zhu, Yingying
Powiązania:
https://bibliotekanauki.pl/articles/2073879.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kopalnia węgla
ochrona środowiska
osiadanie powierzchni
coal mine filling mining
environmental protection
technology of surface subsidence control
engineering applications
Opis:
According to the requirements of green mine construction and the coordinated development of environmental protection regulations, the existing filling technologies in China are compared and analysed. Several types of technologies are discussed, including the dry filling technology for gangue, grouting and filling for separated strata zones in overburden, grouting and filling technology for caving gangue fissures, paste and paste-like filling, high-water and ultra-high-water filling, and continuous mining and continuous filling. Then, the characteristics of these individual technologies are analysed. Through the analysis and comparison of these technologies, considering the requirements of green mine construction and coordinated development of environmental protection regulations, it was found that continuous mining and continuous filling technology is a feasible mean for constructing green mines and protecting the environment. In this study, the application of continuous mining and continuous filling technology in the Yuxing coal mine is introduced. Results show that surface subsidence was less than 80 mm, and the recovery rate of the working face reached 95%. This indicates that continuous mining and continuous filling technology can solve the problems of surface subsidence, environmental damage, and coal resource waste. Finally, the development prospects of continuous mining and continuous filling technology are proposed, providing theoretical and technical support for similar mining.
Źródło:
Archives of Mining Sciences; 2021, 66, 4; 611--624
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of chosen aspects of a tank gassing-up process on board liquefied petroleum gas carrier. Part II
Autorzy:
Wieczorek, Agnieszka
Powiązania:
https://bibliotekanauki.pl/articles/1845489.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
filling
tank
gassing-up
ideal gas
gas mixing
ethylene
nitrogen
inert gas
cargo
vapour
Opis:
The paper presents a thermodynamic analysis of the removal of an inert gas from the tank using the vapor of liquefied petroleum gas cargo (called cargo tank gassing-up operation). For this purpose a thermodynamic model was created which considers two extreme cases of this process. The first is ‘piston pushing’ of inert gas using liquefied petroleum gas vapour. The second case is the complete mixing of both gases and removal the mixture from the tank to the atmosphere until desired concentration or amount of liquefied petroleum gas cargo in the tank is reached. On the example of nitrogen as inert gas and ethylene as a cargo, by thermodynamic analysis an attempt was made to determine the technical parameters of the process, i.e., pressure in the tank, temperature, time at which the operation would be carried out in an optimal way, minimizing the loss of cargo used for gassingup. Calculations made it possible to determine the amount of ethylene used to complete the operation and its loss incurred as a result of total mixing of both gases.
Źródło:
Archives of Thermodynamics; 2021, 42, 2; 59-69
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Backfill of a Mined-Out Gold Ore Deposit with the Cemented Rubber-Cord and Waste Rock Paste: Environmental Changes in Aqueous Media
Autorzy:
Danilov, Alexander
Korelskiy, Denis
Matveeva, Vera
Horttanainen, Mika
Powiązania:
https://bibliotekanauki.pl/articles/1955427.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
filling mixture
backfill mixture
physical properties
chemical properties
elements migration
waste utilization
mined-out space filling
Opis:
Assessment of the dynamics of changes in the physical and chemical properties and morphological composition of the filling mixture as well as the identification of the elements capable of migrating into the environment is an important part of assessing the environmental efficiency of such an environmental measure during the filling of mined-out space of an ore deposit. During scientific research, the environmental safety mined-out space filling technology at the gold ore deposit by the mixture of rock waste, cement and crushed car tires was investigated. The authors carried out a set of laboratory studies and created a physical model of groundwater infiltration. Under laboratory conditions, this model allowed the experiment to evaluate the migration of elements and substances from the filling mixture into the environment to assess the risks of secondary pollution. The potential hazard of element migration from the backfill mixture into the environment was determined as a result of testing the backfill mixture on a bench with washing using the model solution that emits drainage water. During research, it was revealed that under the conditions of an ore deposit, the filling mixture components transformation would not lead to hazardous hydrochemical and hydrogeochemical areas or pollution stream formation.
Źródło:
Journal of Ecological Engineering; 2021, 22, 7; 190-203
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Blades interaction and non-stationarity of flow in vertical-axial wind turbines
Autorzy:
Rozhkova, Ludmila
Krenicky, Tibor
Kuznetsov, Eduard
Nahornyi, Volodymyr
Powiązania:
https://bibliotekanauki.pl/articles/2037426.pdf
Data publikacji:
2021
Wydawca:
STE GROUP
Tematy:
wind turbine
power characteristic
wind potential
filling factor
wind energy utilization
Opis:
Until recently, horizontal-axial wind turbines with blades having a wing profile occupied a predominant position in the world wind energy market. But currently, vertical-axial wind units are of increasing interest and this is understandable from the point of view of their important features as: no requirements for the orientation of the wind turbine to the wind, the possibility of placing electrical and other equipment on the ground, no requirements for changes of blade chord installation angle along its length. The article discusses the aerodynamics of the vertical-axis wind turbines: the range of changes of angles of incoming flow attack on the blade, the dynamics of changes in the magnitude of the absolute speed of flow of the blade on a circular trajectory of its movement depending on the turbine rapidity, and also obtained in experiments interaction effect of the blades in the rotor. The experiments were carried out on wind turbines with original blades (basic version), which were designed to eliminate the shortcomings of low-speed rotors Savonius (low coefficient of use of wind energy) and high-speed rotors Darrieus (lack of self-start).
Źródło:
Management Systems in Production Engineering; 2021, 4 (29); 280-286
2299-0461
Pojawia się w:
Management Systems in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finite element analysis of the impact of the properties of dental wedge materials on functional features
Autorzy:
Czerwiński, M.
Żmudzki, J.
Kwieciński, K.
Kowalczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/2175745.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
dental wedge material
friction
matrix
filling
seal
finite element analysis (FEA)
pressure
materiał klina dentystycznego
tarcie
matryca
wypełnienie
uszczelnienie
analiza elementów skończonych
ciśnienie
Opis:
Purpose: Defect of the interproximal wall of the tooth is filled with use the shaped matrix and wedge which seals bottom margin during filling. Better fit of the wedge and equalization of the pressure forces on the matrix is achieved by the compliance of the wedge structure through cuts and perforations and the use of silicone materials and unidirectionally expanded polytetrafluoroethylene (ePTFE). The work presents a methodology for model studies of the mechanics of dental wedges in order to evaluate and compare the impact of wedge materials on functional features. The hypothesis of the work was that the mechanical properties of ePTFE determine the effectiveness of the dental wedge. Design/methodology/approach: Effect of modulus of elasticity and friction coefficient of wedge and matrix materials on the functional features of the wedge was studied on the way Finite Element Analysis (FEA). Simulation included contact sliding between wedge and matrix what was simulated in nonlinear large displacements regime. The sealing evaluation criterion was the pressure distribution between the wedge and matrix below the lower edge of the defect. Displacement values were the criterion for the loss of convexity as a result of matrix deformation. Findings: The material for the wedge should be characterized by a low coefficient of friction, low elasticity (ensuring high compliance of the wedge) and at the same time the ability to large permanent deformations, which allows for plastic shaping of the matrix from the side of the defect in order to achieve the required wall convexity and the tangent point. Research limitations/implications: Results show tendency of phenomena in limitation to model simplification of the interdental gap and the ideal adhesion of the matrix to the tooth and linear elasticity of materials. Practical implications: The material that best meets the requirements is unidirectionally expanded polytetrafluoroethylene, which has one of the lowest coefficients of friction and very high plasticity necessary to shape the matrix from the inside of the cavity. Originality/value: Methodology of model study and criteria of functional characteristics of dental wedge was presented.
Źródło:
Archives of Materials Science and Engineering; 2021, 112, 1; 32--41
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Górnicze metody zabezpieczania wyrobisk kopalń Wieliczki i Bochni przed zagrożeniem zawałowym
Mining methods of protecting the excavations of Wieliczka and Bochnia mines against the cave-in hazard
Autorzy:
Charkot, Józef
Powiązania:
https://bibliotekanauki.pl/articles/2055007.pdf
Data publikacji:
2021-12-10
Wydawca:
Muzeum Żup Krakowskich Wieliczka
Tematy:
kopalnia
szyb
chodnik
komora
zabezpieczanie
obudowa
kaszt
podsadzka
a mine
a shaft
a gallery
a chamber
securing
timbering
a box-crib
filling material
Opis:
Eksploatacja soli w kopalniach Wieliczki i Bochni wymagała systematycznego prowadzenia prac zabezpieczających. Na przestrzeni wieków zmieniano lub modyfikowano metody ich realizacji. W artykule przedstawiono sposoby zabezpieczania poszczególnych rodzajów wyrobisk: szybów, szybików, chodników i komór. Szyby od XIII do XIX w. miały z reguły obudowę drewnianą i prostokątny przekrój. Od początku XX w. nowo zgłębiane szyby otrzymywały obudowę murowaną. Wymieniano również obudowy drewniane na murowane. Szybiki na odcinkach przechodzących przez pokłady i bryły soli oraz zwięzłe skały płonne pozostawiano bez obudowy, inne zabezpieczano obudową drewnianą. Chodniki w bardzo dobrych warunkach geologicznych nie wymagały zabezpieczeń, jednak w zdecydowanej większości posiadają różnorodne odmiany obudowy drewnianej. Pierwotnym, powszechnie stosowanym sposobem zabezpieczania komór było pozostawianie solnej łuski ochronnej. W rozległych komorach już od XIV w. stawiano filary solne. Od tego stulecia budowano również kaszty. Od początku działalności górniczej jednym ze sposobów ochrony komór przed destrukcją było ich podsadzanie. Do XVIII w. podsadzkę stanowił urobek pozyskiwany podczas prac podziemnych (skały płonne, zanieczyszczona sól). W Wieliczce w XIX w. rozpoczęto jej transport z powierzchni. Początkowo była to ziemia, a od początku XX w. piasek. Systematyczne podsadzanie piaskiem na sucho prowadzono do II wojny światowej, incydentalnie w latach 60. XX w. Od lat 80. tego stulecia prowadzi się podsadzanie hydrauliczne. W ten sposób zabezpieczono zasadniczą część wyrobisk, które nie zostały objęte ochroną konserwatorską.
The exploitation of salt in the Wieliczka and Bochnia mines required systematic protection works. Over centuries, the methods of their implementation have been changed or modified. The article presents methods of securing specific types of mine workings: shafts, pit-holes, galleries and chambers. Between the thirteenth and nineteenth century, shafts generally had a timbering and a rectangular cross-section. It was at the beginning of the 20th century that newly sunk shafts started to receive a brick lining. Timbering was also replaced with brick lining. Within sections passing through the deposits and blocks of salt as well as compact waste rocks, pit-holes were left without timbering, while others were secured with it. In very good geological conditions, galleries did not require any protection, however, the vast majority of them have various types of timbering. The original, commonly used method of securing chambers was to leave salt protective slices. Salt pillars had already been erected in large chambers since the 14th century. It is also then that the first box-cribs were built. From the beginning of mining activity, one of the methods of protecting the chambers from destruction was to backfill them. Until the 18th century, the filling material consisted of the output obtained in the course of underground works (waste rocks, contaminated salt). In Wieliczka its transport from the surface started in the 19th century. Initially, it was earth, and from the beginning of the 20th century – sand. Systematic dry backfilling had been carried out until World War II, and incidentally in the 1960’s. Hydraulic backfilling has been carried out since the 1980’s. That is how the essential part of the excavations, which were not under conservation protection, was secured.
Źródło:
Studia i Materiały do Dziejów Żup Solnych w Polsce; 2021, XXXV, 1; 128-199
0137-530X
Pojawia się w:
Studia i Materiały do Dziejów Żup Solnych w Polsce
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Internal mechanism of asymmetric deformation and failure characteristics of the roof for longwall mining of a steeply dipping coal seam
Autorzy:
Luo, Shenghu
Wang, Tong
Wu, Yongping
Huangfu, Jingyu
Zhao, Huatao
Powiązania:
https://bibliotekanauki.pl/articles/1853910.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
odkształcenie
pokłady węgla
szyb kopalniany
steeply dipping seam
gangue
slip filling
deformation failure
main roof
angle effect
Opis:
Stability control of the roof is the key to safe and efficient mining of the longwall working face for a steeply dipping coal seam. In this study, a comprehensive analysis was performed on the roof destruction, migration, and filling characteristics of a steeply dipping longwall working face in an actual coalmine. Elastic foundation theory was used to construct a roof mechanics model; the effect of the coal seam inclination angle on the asymmetric deformation and failure of the roof under the constraint of an unbalanced gangue filling was considered. According to the model, increasing the coal seam angle, thickness of the immediate roof, and length of the working face as well as decreasing the thickness of the coal seam can increase the length of the contact area formed by the caving gangue in the lower area of the slope. Changes to the length of the contact area affect the forces and boundary conditions of the main roof. Increasing the coal seam angle reduces the deformation of the main roof, and the position of peak deflection migrates from the middle of the working face to the upper middle. Meanwhile, the position of the peak rotation angle migrates from the lower area of the working face to the upper area. The peak bending moment decreases continuously, and its position migrates from the headgate T-junction to the tailgate T-junction and then the middle of the working face. Field test results verified the rationality of the mechanics model. These findings reveal the effect of the inclination coal seam angle on roof deformation and failure and provide theoretical guidance for engineering practice.
Źródło:
Archives of Mining Sciences; 2021, 66, 1; 101-124
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Geometrical Model of Woven Fabric Taking into Account the Change of Its Form, Size and Lateral Bending
Nowy model geometryczny tkaniny uwzględniający zmianę jej formy, rozmiaru i zgięcia bocznego
Autorzy:
Grechukhin, A. P.
Rudovskiy, Pavel Hikolayevich
Powiązania:
https://bibliotekanauki.pl/articles/1419848.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
fabric
3D simulation
warp
filling
bending
fabric structure
tkanina
symulacja 3D
osnowa
wypełnienie
zginanie
struktura tkaniny
Opis:
This paper suggests a technique for the construction of fabric three-dimensional models based on the piecewise continuous representation of the thread surface. The approach allows to exclude such simulation defects as "interpenetration" of threads in the fabric, and takes into account the geometric features of the thread structure, the possibility of their bending in several planes, and changes in the form and sectional area. The geometric models obtained can be used to analyse the forces and deformations occurring in the fabric with the help of the finite-element simulation programs in various specialised software complexes, such as ANSYS, LS-DYNA, ABAQUS, NASTRAN etc. The structure parameters which are difficult to calculate using standard techniques, e.g. the pore volume and contact area between threads can be calculated with the help of describing the fabric three-dimensional structure.
W artykule zaproponowano technikę konstrukcji trójwymiarowych modeli tkanin w oparciu o odcinkowo ciągłą reprezentację powierzchni nici. Podejście to pozwoliło wykluczyć defekty symulacyjne, takie jak „przenikanie się” nici w tkaninie, a także uwzględniło cechy geometryczne struktury nici, możliwość ich zginania w kilku płaszczyznach oraz zmiany kształtu i pola przekroju. Uzyskane modele geometryczne mogą być wykorzystane do analizy sił i odkształceń występujących w tkaninie za pomocą programów do symulacji elementów skończonych w różnych specjalistycznych kompleksach programowych, takich jak ANSYS, LS-DYNA, ABAQUS, NASTRAN itp. Ponadto parametry struktury, które są trudne do obliczenia przy użyciu standardowych technik, np. objętość porów i powierzchnia styku między nitkami mogą być z powodzeniem określone za pomocą zaproponowanej w pracy techniki konstrukcji trójwymiarowych modeli tkanin.
Źródło:
Fibres & Textiles in Eastern Europe; 2021, 2 (146); 20-24
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reducing Melt Surface Turbulence by Employing Surge and Filter in a Conventional Non-Pressurizing Gating System: Simulation and Experiment
Autorzy:
Baghani, Amir
Kheirabi, Ali
Bahmani, Ahmad
Khalilpour, Hamid
Powiązania:
https://bibliotekanauki.pl/articles/2049678.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum casting
filter
surge
oxide bifilms
failure analysis
Weibull module
mold filling simulation
Opis:
Tensile strength of aluminum castings has been improved by employing surge and filter in a conventional non-pressurizing gating system. For this purpose, three non-pressurizing bottom-gating systems were designed where the first design was a simple design with no filter and no surge, in the second design filter and in the third one surge was added to the end of runner. Tensile strength, Weibull module, scanning electron microscopy, chemical analysis, and melt pattern during the mold filling were thoroughly analyzed to compare these three designs. it was observed that employing filter and surge in the gating system reduces flow kinetic energy and consequently avoid surface turbulence and air entrainment, which leads to castings with fewer defects and higher reliabilities. Finally, it found that appropriate use of surge in the running system can be as effective as employing a filter in reducing melt front velocity.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 2; 397-405
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 152

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