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Tytuł:
Some Effects on the Temperature of the Mine Air at the Heading Face
Autorzy:
Nguyen, Van Quang
Nguyen, Van Thinh
Nguyen, Cao Khai
Pham, Van Chung
Powiązania:
https://bibliotekanauki.pl/articles/2020221.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
numerical modeling
CFX
ventilation duct position
heading face
temperature of air mine
wentylacja
kopalnie
Opis:
Currently, with the increase in mining output leading to deeper mining levels, the volume of heading face serving production has also increased. The thermal environment tends to worsen when digging deep due to the geothermal's effect, which increases the air temperature at the heading face. According to QCVN01/2011-BCT, the temperature at the heading face is not allowed to exceed 300C. To ensure this, in Vietnam today, mainly forced ventilation method uses local fans to provide a clean amount of air to ensure a favorable environment for workers. With the forced ventilation method, the duct position is usually arranged on the side, and the distance from the duct mouth to the heading face is determined to ensure that l < 6√s. In this study, a numerical simulation method by Ansys CFX software is applied to study the influence of several factors such as duct position, air temperature of duct, and roughness characteristics of roadway on the temperature of the mine air at the heading face. The models are set up with six duct positions and four air temperature of duct parameters. Model 1 (y =1.1 m) is better than models 2 to 6 in terms of temperature distribution and the lowest temperature values. Four models have different wind temperatures, and we can see the significant influence of the inlet air temperature of the duct on the thermal environment of the heading face. The results show that with the model T = 297.15K, the temperature value on the roadway length is guaranteed as specified < 303K. The result is a reference for determining the duct position and cool for the high-temperature heading face.
Źródło:
Inżynieria Mineralna; 2021, 2; 423--432
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Solution to Ensure Ventilation when Expanding the Area of Cam Thanh Underground Coal Mine, Ha Long Coal Company, Vietnam
Autorzy:
Nguyen, Cao Khai
Nguyen, Van Tinh
Nguyen, Phi Hung
Nguyen, Van Quang
Powiązania:
https://bibliotekanauki.pl/articles/2020950.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
mine ventilation
mine ventilation and safety
Cam Thanh mines area
ventilation system adjustment
fan operating points
kopalnie
wentylacja
Wietnam
Opis:
In the process of underground mining, the mining system changes for various reasons. One of the main reasons is changes in the mining production plans, especially the scales and outputs. Nowadays, coal mines in Vietnam have been expanding in width and depth, and so have the mines’ ventilation systems. Consequently, there will be changes in the alteration of the structure of the design ventilation system, which reduces the effectiveness of the ventilation and does not meet the main objective of mine ventilation, directly affect the safety of the working environment in the mine. Therefore, it is necessary to research the improvement of the ventilation system with the development and specific conditions of underground coal mines in Vietnam, improving the efficiency of the ventilation work and assuring the safety of the mine environment. Cam Thanh coal mine, Ha Long coal company, Vietnam, is the case study for this research. The article considers the plan of increases the mining output by more than 1.5 times, propose solutions to improve the ventilation system accordingly, helping the company proactively implement the production plan, ensure the working environment's safety, and reduce the costs of mine ventilation.
Źródło:
Inżynieria Mineralna; 2021, 2; 533--542
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Study on Effects of Airflow Parameters on the Air Temperature the at Mechanized Longwall of Mongduong Coal Mine
Autorzy:
Nguyen, Hong Thi
Nguyen, Quang Van
Powiązania:
https://bibliotekanauki.pl/articles/27323262.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
numerical modelling
Ansys CFX
mechanized longwall
temperature of air mine
velocity of air mine
Mongduong coal mine
modelowanie numeryczne
temperatura
powietrze kopalniane
Wietnam
Opis:
The increasing depth of extraction and the degree of mechanization leading to the risk of workers working in poor microclimate conditions has become one of the major safety issues in coal mines. During the survey of the current microclimate in Mongduong coal mine, it showed that the temperature of the mechanized longwall exceeded the permissible regulations (t°≤ 30°C), the air humidity is about 95–100%. The reason for the increase of air temperature in longwall is due to geothermal, heat radiated from the longwall equipment and the inlet wind high temperature. To improve the thermal environment in the mechanized longwall area, Vietnam's coal mines open use ventilation, but the efficiency is not high. Therefore, the paper evaluated the influence of airflow on the temperature of the longwall, 7 models with different air flow velocities and 3 models with inlet air temperature have been created in ICM-CFD and simulated by Ansys CFX software. The environment temperature of each model was evaluated by analyzing the average temperature of the roadway section, the cross-section distribution of the roadway temperature and the velocity streamline of the whole roadway. As a result, the air flow rate increases leading to the air temperature in the longwall decreases, however the wind speed is limited. The inlet temperature of the gas stream is an important factor that affects the thermal environment in the longwall. The results of the article are the basis for making solutions to improve the thermal environment suitable for high-temperature longwall.
Źródło:
Inżynieria Mineralna; 2023, 2; 89--96
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Marine Sediments with a Subbottom Profilers System in West Coast of Camau, Vietnam
Autorzy:
Dung, Nguyen Quang
Giang, Nguyen Van
Thanh, Le Ngoc
Powiązania:
https://bibliotekanauki.pl/articles/27323269.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
west coast of Camau
high-resolution shallow seismic
sub-bottom profiler
cross-section
Holocene-Pleistocene sediments
Sejsmika
Wietnam
profile
Opis:
The west coast of Camau (Southeast Vietnam) connects two semi-enclosed East Sea and Thailand Bays, allowing water exchange between them. Despite its importance to the oceanographic evolution of the region, it has still been poorly studied. Therefore, Subbottom profilers are used across shallow sea waters with some applications, such as sea-level studies, sedimentation process and geomorphology. In the whole survey area, 6 high-resolution shallow seismic measurements have been performed with a total length of 60.6 km, and all have recorded good reflected signals in the range 20–70 ms. In this section, physical characteristics and nature of petrology in the survey environment are quite uniformly shown. The topography of the seabed in the survey area tends to be gradually shallower from west to east, and is relatively flat. Particularly, on the cross section of the T1 line, it is visible that the first section of the line has a rather steep and deep terrain, which may be the slope of the continental shelf in the survey area. Wedge-shaped, oblique, corrugated and transverse structures all appear on the cross-sections. In the survey area, the shallow geological structure in the Holocene sediments is divided into 4 layers, and the structural boundary between the Holocene and Pleistocene sediments at the depth of 25–35 m is observed. In addition, geological faults are also detected on geological sections from seismic sections. For instance, at the section of T6 line, two faults were detected at the beginning of the line. The displacement amplitude of these faults ranges between 1.5–4 m. This new dataset will contribute to future comprehension of the geologic and oceanographic evolution.
Źródło:
Inżynieria Mineralna; 2023, 2; 215--223
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulating and Predicting Escape Routes for Ventilation Network of Duong Huy Coal Company using Ventsim DESIGN Software
Symulacja i przewidywanie dróg ewakuacyjnych dla Sieci Wentylacyjnej Spółki Węglowej Duong Huy przy użyciu oprogramowania VENTSIM DESIGN
Autorzy:
Duy Huy, Nguyen
Cao Khai, Nguyen
Van Thinh, Nguyen
Van Quang, Nguyen
Minh Chien, Nguyen
Khac Duy, Nguyen
Powiązania:
https://bibliotekanauki.pl/articles/2172066.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
ventilation network
Ventsim DESIGN
escape routes
Duong Huy coal company
vinacomin
sieć wentylacyjna
drogi ewakuacyjne
spółka węglowa Duong Huy
Vinacomin
Opis:
In underground coal mining, the ventilation task plays an important role because it ensures enough fresh air for workers and decrease negative effects of deleterious gases released from coal seam as well as blasting explosions. Furthermore, when coal mines go deeper, the ventilation task is more and more important. In order to guarantee good ventilation performance, we should apply a simulation software. In this article, we present the application of Ventsim DESIGN software for ventilation network of Duong Huy Coal company as well as prediction of escape routes in urgent cases. The simulation results demonstrate that the software offers good performance, stable operation as well as the suitable escape routes in urgent cases.
W podziemnym górnictwie węgla wentylacja odgrywa ważną rolę, ponieważ zapewnia wystarczającą ilość świeżego powietrza dla pracowników i zmniejsza negatywne skutki uwalniania się szkodliwych gazów z pokładów węgla oraz możliwość wystąpienia wybuchów. Ponadto, gdy eksploatacja sięga głębiej, zadanie wentylacji jest coraz ważniejsze. W celu zagwarantowania dobrej wydajności wentylacji do obliczeń sieci wentylacyjnej stosuje się oprogramowanie symulacyjne. W artykule przedstawiono zastosowanie oprogramowania Ventsim DESIGN dla obliczenia sieci wentylacyjnej kopalni Duong Huy oraz przewidywania dróg ewakuacyjnych w nagłych przypadkach. Wyniki symulacji pokazują, że program dobrze wylicza wydajność sieci , warunki stabilnej pracy oraz odpowiednie drogi ewakuacyjne w nagłych przypadkach.
Źródło:
Inżynieria Mineralna; 2022, 2; 151--157
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Static behaviour of functionally graded plates resting on elastic foundations using neutral surface concept
Autorzy:
Van-Loi, Nguyen
Minh-Tu, Tran
Van-Long, Nguyen
Quang-Huy, Le
Powiązania:
https://bibliotekanauki.pl/articles/1845053.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
static analysis
functionally graded plate
Winkler-Pasternak foundation
physical neutral surface
four-variable refined theory
analiza statyczna
podłoże typu Winkler-Pasternak
fizycznie neutralna powierzchnia
Opis:
In this study, static behaviors of functionally graded plates resting on Winkler-Pasternak elastic foundation using the four-variable refined theory and the physical neutral surface concept is reported. The four-variable refined theory assumes that the transverse shear strain has a parabolic distribution across the plate’s thickness, thus, there is no need to use the shear correction factor. The material properties of the plate vary continuously and smoothly according to the thickness direction by a power-law distribution. The geometrical middle surface of the functionally graded plate selected in computations is very popular in the existing literature. By contrast, in this study, the physical neutral surface of the plate is used. Based on the four-variable refined plate theory and the principle of virtual work, the governing equations of the plate are derived. Next, an analytical solution for the functionally graded plate resting on the Winkler-Pasternak elastic foundation is solved using the Navier’s procedure. In numerical investigations, a comparison of the static behaviors of the functionally graded plate between several models of displacement field using the physical neutral surface is given, and parametric studies are also presented.
Źródło:
Archive of Mechanical Engineering; 2021, LVIII, 1; 5-22
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Responses of the Micro-Crustacean, Daphnia magna, across Five Generations Continuously Exposed to Di-2-Ethylhexyl Phthalate in Mekong River Water
Reakcje mikroskorupiaków, Daphnia magna, w ciągu pięciu pokoleń stale narażonych na działanie ftalanu di-2-etyloheksylu w wodzie rzeki Mekong
Autorzy:
Tran, Vinh-Quang
Nguyen, Van-Tai
Dao, Thanh-Son
Powiązania:
https://bibliotekanauki.pl/articles/2175329.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
chronic effects
Daphnia magna
energy cost
life traits
plastic additives
skutki chroniczne
zużycie energii
cechy życiowe
dodatki do tworzyw sztucznych
Opis:
Plastic pollution has been considered as an emerging environmental problem, and is among the ecological and human health concerns. Detrimental impacts of plastic pollution on living things are closely related to the plastic additives added onto the polymer during plastic manufacture. Di-2-ethylhexyl phthalate (DEHP) is one of the most common plasticizers and is usually found in water environment worldwide. Plastic additives can cause many negative effects on aquatic organisms such as fish and zooplankton. This study aimed to assess the chronic effects of DEHP on the life history traits of an ecotoxicological model micro-crustacean, Daphnia magna, across five generations (F0–F4). We used the natural water from Mekong River in Vietnam as the medium for the D. magna incubation in laboratory conditions. The concentrations of trace elements (e.g., metals and pesticides) in the natural water were under detection levels of equipment or very low which was sufficient for D. magna to grow well. The results showed that the body length was the main endpoint of the organisms inhibited by DEHP across all generations. DEHP adversely impacted the survival and fecundity of D. magna in the fourth generation (F3) only. The adverse effects of DEHP on body length of D. magna should be the consequence of the energy cost and allocation in the exposed organisms. The survival and reproduction responses of D. magna to DEHP across five generations could be explained by (i) the severe effects of the chemical on many individuals in the organism cohort, and (ii) toxin-tolerant development in the remaining exposed organisms. Although the trace elements in natural water from Mekong River were not toxic to D. magna at very low concentrations, together with DEHP they might enhance impacts on the organism. Besides, a multigenerational exposure to DEHP would reflect clearer impacts on the organism than a single exposure. Our results could be useful for extrapolation on the influence of plasticizers on freshwater zooplankton in nature.
Zanieczyszczenie tworzywami sztucznymi zostało uznane za narastające zagrożenie środowiskowe i jest jednym z problemów ekologicznych związanych ze zdrowiem człowieka. Szkodliwy wpływ zanieczyszczenia tworzywami sztucznymi na organizmy żywe jest ściśle związany z dodatkami tworzyw sztucznych dodawanymi do polimeru podczas produkcji tworzyw sztucznych. Ftalan di2-etyloheksylu (DEHP) jest jednym z najpowszechniejszych plastyfikatorów i zwykle występuje w środowisku wodnym na całym świecie. Dodatki do tworzyw sztucznych mogą powodować wiele negatywnych skutków dla organizmów wodnych, takich jak ryby i zooplankton. Badania przedsatwione w artykule miały na celu ocenę ciągłego wpływu DEHP na cechy historii życia modelu ekotoksykologicznego mikroskorupiaka, Daphnia magna, w ciągu pięciu pokoleń (F0–F4). Jako pożywkę do inkubacji D. magna w warunkach laboratoryjnych wykorzystano naturalną wodę z rzeki Mekong w Wietnamie. Stężenia pierwiastków śladowych (np. metali i pestycydów) w naturalnej wodzie były poniżej poziomu wykrywalności sprzętu lub bardzo niskie, co było wystarczające, aby D. magna dobrze się rozwijała. Wyniki pokazały, że długość ciała była głównym punktem oceny rozwoju organizmów hamowanego przez DEHP we wszystkich pokoleniach. DEHP negatywnie wpłynął na przeżywalność i płodność D. magna jedynie w czwartym pokoleniu (F3). Negatywny wpływ DEHP na długość ciała D. magna powinien być konsekwencją zużycia energii i jej alokacji w narażonych organizmach. Reakcje D. magna na przetrwanie i reprodukcję pod wpływem DEHP w ciągu pięciu pokoleń można wytłumaczyć (i) poważnym wpływem substancji chemicznej na wiele osobników w populacji organizmów oraz (ii) rozwojem tolerancji na toksyny u pozostałych narażonych organizmów. Chociaż pierwiastki śladowe w naturalnej wodzie z Mekongu nie były toksyczne dla D. magna w bardzo niskich stężeniach, to razem z DEHP mogą nasilać oddziaływanie na organizm. Poza tym wielopokoleniowe narażenie na DEHP odzwierciedlałoby wyraźniejszy wpływ na organizm niż jednorazowe narażenie. Przedstawione wyniki mogą być przydatne do ekstrapolacji wpływu plastyfikatorów na zooplankton słodkowodny w przyrodzie.
Źródło:
Inżynieria Mineralna; 2022, 2; 77--83
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variation in Growth and Yield of Sacha Inchi (Plukenetia Volubilis L.) under Different Ecological Regions in Vietnam
Autorzy:
Van, Quang Vu
Thi, Ngoc Yen Pham
Thi, Tram Nguyen
Van, Muoi Nguyen
Van, Thanh Le
Thi, Bich Ngoc Vu
Thi, Bich Hong Nguyen
Powiązania:
https://bibliotekanauki.pl/articles/2173335.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
ecological region
growth
sacha inchi
selection
yield
Opis:
The sacha inchi seeds (Plukenetia Volubilis L.), collected from different ecological regions of Vietnam (the Northern Mountainous region, the North Central region, and Central Highlands Area), were sown in the spring crop (March 2020) in Gia Lam district, Hanoi city, Vietnam. The variety S18 was copyrighted by Ministry of Agriculture and Rural Developmentof Vietnam in 2019 as a special medicinal plant variety. During the period of 26 months after planting, the agronomical parameters, growth and development characteristics (leaf form, number of inflorescences per branches, number of female flowers per inflorescences, etc.), pests and diseases, yields and yield components (number of seeds per fruit, seed weight, seed grain, etc.), ratio of kernel per seed and ratio of oil per seed were evaluated. The evaluation results show that the collected sacha inchi lines have a time from sowing to flowering and fruiting of 108–125 days, a fruiting to ripening of 123–125 days, and a time from sowing to harvesting the first batch of 244–250 days. The annual harvest is carried out at two main times: May–June and November–January. The actual yield of the first two periods is high (2.66–3.07 tons per hectare), and the highest yield is collected in the Northern Mountainous area is 3.07 tons per hectare (in Tuyen Quang province), while and 3.01 tons per hectare are collected in the North Central region (in Thanh Hoa province). In the nursery, root rot caused 2.1–5.3% deaths and green wilt caused 3.1–4.8% deaths of seedlings. In the planting garden, fruit borers, stem borers, cavity worms and red spiders were discovered, causing more serious damage than other types (from 5 to over 50%). The results of evaluation of growth, development, yield components and yield showed that the sacha inchi lines collected in the North Central region (in Thanh Hoa province) and the Northern Mountainous region (in Tuyen Quang province) is the best.
Źródło:
Journal of Ecological Engineering; 2022, 23, 8; 162--169
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of solid and ionic surface reaction form to surface quality when using chemical-mechanical slurry polishing
Autorzy:
Duc, Le Anh
Hieu, Pham Minh
Mai, Nguyen Trong
Trong, Thai Van
Quang, Nguyen Minh
Powiązania:
https://bibliotekanauki.pl/articles/2171776.pdf
Data publikacji:
2022
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
chemical-mechanical slurry
polishing
abrasive particle
ionic surface reaction
yttrium aluminum garnet
surface roughness
Opis:
The process of removing machining residues using chemical-mechanical slurry (CMS) has an important place in the creation of ultra-precise components in optical devices. Based on this feature, this work investigates the efficiency of the CMS polishing process by comparing the surface reaction modes by the ionic and solid reaction modes when polishing the yttrium aluminum garnet (YAG) and sapphire crystal. The study procedures were conducted to clarify the polishing performance corresponding to these two reaction types. The obtained experiments results show that the balance between the mechanical effect process using CMS polishing technology with chemical effect can be achieved with the ionic reaction mode. The results also show that the ionic surface reaction modes give more uniform material removal than the solid reaction on YAG and sapphire crystal surfaces. Therefore, the surface quality when polished by CMS technology with ionic surface reaction modes is better than that of solid surface reaction.
Źródło:
Journal of Machine Engineering; 2022, 22, 4; 82--94
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design optimization of compliant mechanisms for vibration assisted machining applications using a hybrid Six Sigma, RSM-FEM, and NSGA-II approach
Autorzy:
Pham, Huy-Tuan
Nguyen, Van-Khien
Dang, Quang-Khoa
Duong, Thi Van Anh
Nguyen, Duc-Thong
Phan, Thanh-Vu
Powiązania:
https://bibliotekanauki.pl/articles/24084644.pdf
Data publikacji:
2023
Wydawca:
Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:
compliant mechanism
multi-objective optimisation
Six Sigma
NSGA-II
Opis:
Vibration-assisted machining, a hybrid processing method, has been gaining considerable interest recently due to its advantages, such as increasing material removal rate, enhancing surface quality, reducing cutting forces and tool wear, improving tool life, or minimizing burr formation. Special equipment must be designed to integrate the additional vibration energy into the traditional system to exploit those spectacular characteristics. This paper proposes the design of a new 2-DOF high-precision compliant positioning mechanism using an optimization process combining the response surface method, finite element method, and Six Sigma analysis into a multi-objective genetic algorithm. The TOPSIS method is also used to select the best solution from the Pareto solution set. The optimum design was fabricated to assess its performance in a vibration-assisted milling experiment concerning surface roughness criteria. The results demonstrate significant enhancement in both the manufacturing criteria of surface quality and the design approach criteria since it eliminates modelling errors associated with analytical approaches during the synthesis and analysis of compliant mechanisms.
Źródło:
Journal of Machine Engineering; 2023, 23, 2; 135--158
1895-7595
2391-8071
Pojawia się w:
Journal of Machine Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of rudder and blade pitch on hydrodynamic performance of marine propeller using CFD
Autorzy:
Quang, Pham Ky
Hung, Phan Van
Cong, Nguyen Chi
Tung, Trinh Xuan
Powiązania:
https://bibliotekanauki.pl/articles/32899108.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
rudder
blade pitch
propeller
CFD
Opis:
The use of computational fluid dynamics (CFD) to predict internal and external flows has risen dramatically in the past decade. This research aims to use the commercial software, ANSYS Fluent V.14.5, to illustrate the effects of the rudder and blade pitch on the hydrodynamic performance of the marine propeller by experimenting with propellers and rudders of the M/V Tan Cang Foundation ship, which has designed conditions as follows: diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m; boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller and some important results showed that the maximum efficiency of the propeller is 0.66 with the open water propeller and 0.689 with the rudder‒propeller system at the advance ratio of 0.6. The obtained outcomes of this research are a significant foundation to calculate and design an innovative kind of propulsion for ships with high performance.
Źródło:
Polish Maritime Research; 2022, 2; 55-63
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fracture Mechanism of Hard Main Roof and Determining the Width of Coal Pillars when Extracting Flat-lying Coal Seams
Autorzy:
Le, Quang Phuc
Dao, Van Chi
Nguyen, Phi Hung
Vu, Thai Tien Dung
Powiązania:
https://bibliotekanauki.pl/articles/27323252.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
failure mechanism
coal pillar
stress distribution
roadway deformation
retained roadway
hard main roof
gob-side entry
węgiel
filary
stabilność
Wietnam
Opis:
In underground coal mining, the stability of roadways and gob-side entry depends on the coal pillar width. An unreasonable width of the coal pillar will cause the roadway to be in a dangerous zone of influence of the abutment pressure, leading to severe roadway deformation. This paper studies the fracture mechanism of the hard main roof and reasonable coal pillar width to protect the stability of gob-side entry driving. The research results show that when mining a coal seam under a hard main roof, the console of the main roof on the edge of the coal seam has the form of hinge structure. The great load of the roof layers and the rotation of the console are the main causes leading to the variation of the stress field in the coal seam. According to the development law of the stress field, after the main roof completes the collapse process, the peak of the maximum stress will move deep into the solid coal seam, and on the edge of the coal seam it will form a low-stress zone. Research results from the case of Seam #11 of Khe Cham coal mine, Vietnam show that the gob-side entry will be well stabilized when the narrow coal pillar between it and the boundary of the gob is 4–5 m.
Źródło:
Inżynieria Mineralna; 2023, 2; 271--280
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of the Resampling Methods for Gridded DEM Downscaling
Porównanie metod ponownego próbkowania dla skalowanego w dół zmniejszania DEM
Autorzy:
Nguyen, Quang Minh
Nguyen, Thi Thu Huong
La, Phu Hien
Duong, Thi Tuyet Nhung
Nguyen, Thi Minh Hong
Vu, Van Anh
Powiązania:
https://bibliotekanauki.pl/articles/318242.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
próbkowanie
skalowanie
DEM
resampling
downscaling
Opis:
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.
Źródło:
Inżynieria Mineralna; 2019, 21, 2/2; 240-248
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Developing an Advanced Soft Computational Model for Estimating Blast-Induced Ground Vibration in Nui Beo Open-pit Coal Mine (Vietnam) Using Artificial Neural Network
Opracowanie zaawansowanego modelu obliczeniowego do szacowania wibracji gruntu wywołanych wybuchem w odkrywkowej kopalni węgla Nui Beo (Wietnam) przy użyciu sztucznej sieci neuronowej
Autorzy:
Nguyen, Hoang
Bui, Xuan‑Nam
Tran, Quang Hieu
Nguyen, Quoc Long
Vu, Dinh Hieu
Pham, Van Hoa
Le, Qui Thao
Nguyen, Phu Vu
Powiązania:
https://bibliotekanauki.pl/articles/317864.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
Wietnam
górnictwo odkrywkowe
sieci neuronowe
Vietnam
open pit mining
artificial neural network
Opis:
The principal object of this study is blast-induced ground vibration (PPV), which is one of the dangerous side effects of blasting operations in an open-pit mine. In this study, nine artificial neural networks (ANN) models were developed to predict blast-induced PPV in Nui Beo open-pit coal mine, Vietnam. Multiple linear regression and the United States Bureau of Mines (USBM) empirical techniques are also conducted to compare with nine developed ANN models. 136 blasting operations were recorded in many years used for this study with 85% of the whole datasets (116 blasting events) was used for training and the rest 15% of the datasets (20 blasting events) for testing. Root Mean Square Error (RMSE), Determination Coefficient (R2), and Mean Absolute Error (MAE) are used to compare and evaluate the performance of the models. The results revealed that ANN technique is more superior to other techniques for estimating blast-induced PPV. Of the nine developed ANN models, the ANN 7-10-8-5-1 model with three hidden layers (ten neurons in the first hidden layer, eight neurons in the second layers, and five neurons in the third hidden layer) provides the most outstanding performance with an RMSE of 1.061, R2 of 0.980, and MAE of 0.717 on testing datasets. Based on the obtained results, ANN technique should be applied in preliminary engineering for estimating blast-induced PPV in open-pit mine.
Źródło:
Inżynieria Mineralna; 2019, 21, 2/2; 58-73
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sediment discharge and storage over the last deglacial highstand period on the central Vietnam shelf off Nha Trang
Autorzy:
Dung, Bui Viet
Stattegger, Karl
Kieu, Nguyen Van
Thanh, Nguyen Trung
Thong, Bui Xuan
Vu, Pham Nguyen Ha
Man, Ha Quang
Trang, Pham Hong
Powiązania:
https://bibliotekanauki.pl/articles/2058662.pdf
Data publikacji:
2019
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
sediment budget
Nha Trang shelf
central Vietnam
Holocene highstand
sequence stratigraphy
Opis:
A sediment budget for the central Vietnam shelf off Nha Trang over the last deglacial Holocene highstand period has been investigated on the basis of shallow seismic and sediment core data and empirical equations. The annual suspended sediment discharge to the Nha Trang shelf ranges from: 4.3 to 5.4 Mt/year. Estimates based on published empirical equations suggest that the sediment discharge by three main local mountainous rivers (the Cai, Dinh and Van Phong rivers) that enter the Nha Trang shelf ranges between 1.7 and 4 Mt/year, which implies that the local rivers discharge approximately 75% of the total annual sediment input to the shelf. The annual sediment supply of the Cai River is approximately 2 and 6 times higher than that of the Dinh and Van Phong rivers, respectively. The highstand sediment depocentre of the Nha Trang shelf is mostly attached to the local river outflows, indicating their importance as the principal sediment supply sources to the shelf. Additional sources of sediment supply to the Nha Trang shelf can probably be related to along-shore transport from the nearby shelves. Calculations based on seismic and sediment core data indicate that the net sediment volume storage on the Nha Trang shelf is approximately 2.15 Mt/year. Approximately 50% of the total sediment yield supplied to the shelf is probably transported along-shore to the south. The sediment budget model for highstand deposits on the Nha Trang shelf is typical for a small mountainous river basin, which is significantly different from that of the large river delta systems in Vietnam such as the Mekong and Red rivers where 90% of the river sediments are captured on the delta plain/subaqueous part and only 10% of the river sediments are transported to the nearby shelf. In contrast, most of the sediments supplied by small mountainous rivers off Nha Trang are transported to the mid-shelf, forming a shore-parallel mud depocentre.
Źródło:
Geological Quarterly; 2019, 63, 2; 395--406
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
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