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Wyświetlanie 1-15 z 48
Tytuł:
Carrier-Influenced Bistable Behaviour in Ring Cavity Configuration
Autorzy:
Nguyen, Ba An
Nguyen, Trung Dan
Hoang, Xuan Nguyen
Powiązania:
https://bibliotekanauki.pl/articles/1920640.pdf
Data publikacji:
1992-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Po
78.20.Dj
Opis:
Bistable output-input light characteristics in the exciton spectral region have been examined in a ring cavity configuration taking ito account the influence of the presence of free carriers in the cavity as well as of the density-dependence of the exciton damping. The resulting modifications could serve as a means to optimize the optical bistable device operation.
Źródło:
Acta Physica Polonica A; 1992, 81, 4-5; 517-525
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AN EXPLORATORY STUDY OF ICT USE IN ENGLISH LANGUAGE LEARNING AMONG EFL UNIVERSITY STUDENTS
Autorzy:
Tri, Dang Hoang
Nguyen, Nhung Hong Thi
Powiązania:
https://bibliotekanauki.pl/articles/941305.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej w Lublinie. IATEFL Poland Computer Special Interest Group
Tematy:
ICT
EFL
Opis:
There has been a large volume of published studies describing the attitudes of teachers and students towards ICT usage to study English; nevertheless, limited research has been conducted to examine the use of ICT in terms of frequency of use, purposes, perceptions, and expectations among EFL students. Thus, the purpose of the current study was to address this research problem. The research used a convenience sample of 149 English major students who were invited to respond to the questionnaire survey. The findings indicated that the participants spent more time using ICT for private purposes than for English learning purposes. Most of them showed their positive attitudes towards ICT use to study English and expected that ICT should be used more frequently in the classroom in order to maximize language learning and teaching. Gaining an understanding of the way the learners employ ICT for their non-educational purposes may help “shed light on how best to determine their educational uses” (Fujimoto, 2012, p.165). Pedagogical implications were also given in this current inquiry.
Źródło:
Teaching English with Technology; 2014, 14, 4; 32-46
1642-1027
Pojawia się w:
Teaching English with Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lithofacies and depositional environments of the Paleogene/Neogene sediments in the Hoanh Bo Basin (Quang Ninh province, NE Vietnam)
Autorzy:
Hoang, V. T.
Wysocka, A.
Phan, D. P.
Nguyen, Q. C.
Ziółkowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/184794.pdf
Data publikacji:
2015
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
terrestrial environments
lithofacies
Paleogene
Neogene
Vietnam
Opis:
The Hoanh Bo Basin is a multiple period formed basin which is associated with the tectonic mechanism due to the activity of the Chi Linh-Hon Gai and Trung Luong Faults during the late Paleogene – early Neogene time. The basin is filled with continental sediments, comprising mainly polymictic conglomerates, sandstones, siltstones, claystones and shales. Coarser-grained polymictic deposits predominate along the northern and western margins of the basin, while different types of siltstones, claystones, even sandstones occur in its center, as well as along its southern and eastern parts toward the Ha Long Bay. The source rocks for sedimentary materials are mainly originated from rocks of the Hon Gai and Ha Coi Formations. Based on the dominant grain-size class, texture, stratification, degree of clast rounding and sorting, 17 lithofacies were determined in the Hoanh Bo Basin infill. The basin is filled by gravelly, sandy and fine-grained lithofacies just covers a modest area but it represents a full of succession of 4 depositional systems including alluvial fan, fluvial, deltaic and lacustrine environments. Alluvial fan and fluvial environments are characterized by an assemblage of lithofacies such as sand- and mud-supported disorganized breccias (Gb), clast- to sand-supported conglomerates (Gmm), clast-supported inverse-graded conglomerates (Gig), planar-cross-bedded conglomerates (Gp), trough cross-bedded conglomerates (Gt), horizontally stratified conglomerates (Gh), planar cross-bedded sandstones (Sp), trough cross-bedded sandstones (St), ripple cross-laminated sandstones (Sr), horizontally bedded sandstones (Sh), massive sandstones (Sm), massive mudstones, siltstones (Fsm), laminated siltstones and mudstones (Fl), massive claystones (Fm) and coaly lithofacies (C); the deltaic assemblage is dominated by planar-cross-bedded conglomerates (Gp), horizontally stratified conglomerates (Gh), planar cross-bedded sandstones (Sp), horizontally bedded sandstones (Sh), low-angle cross-bedded sandstones (Sl); while the lacustrine assemblage consists of ripple cross-laminated sandstones (Sr), horizontally bedded sandstones (Sh), normally graded sandstones (Sng), massive mudstones, siltstones (Fsm), laminated siltstones and mudstones (Fl), massive claystones (Fm) and coaly lithofacies (C).
Źródło:
Geology, Geophysics and Environment; 2015, 41, 4; 353-369
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The efficiency of eco-logistics processes on the food market
Efektywność procesów eko-logistycznych na rynku produktów żywnościowych
Autorzy:
Dorozińska, W.
Hoang, L.
Kwiatkowski, M.
Nguyen, M.
Nowicka, D.
Sikora, M.
Stańko, P.
Quan, L.
Powiązania:
https://bibliotekanauki.pl/articles/112734.pdf
Data publikacji:
2016
Wydawca:
STE GROUP
Tematy:
eco-logistics
reverse logistics
food market
ekologistyka
środowisko
logistyka zwrotna
rynek produktów żywnościowych
Opis:
The paper discusses the question of the efficiency of eco-logistics on the food market. The aim of the article is to present major problems related to the impact of food production processes, packaging, distribution and transport on the environment. It presents the origins of eco-logistics in relation to the concepts of logistics and reverse logistics. It analyses the characteristics and general assumptions of the efficiency of eco-logistics processes and describes food market as well as its impact on the natural environment. Furthermore it discusses the issue of waste generation and presents business entities operating on the food market in the aspect of their further development. The question of sanitary standards for products of the food sector is analyzed as well as the dynamics of the development of technologies used in the processes of reverse logistics, changing exogenic expectations and systems of values.
Artykuł podejmuje problematykę efektywności eko-logistyki na rynku produktów żywnościowych. Celem artykułu jest przedstawienie głównych problemów oddziaływania procesów wytwórczych produktów żywnościowych, opakowań, dystrybucji oraz transportu na środowisko. Przedstawiono w nim genezę eko-logistyki w nawiązaniu do pojęcia logistyka i logistyka zwrotna. Została przedstawiona charakterystyka oraz ogólne założenia efektywności procesów eko-logistycznych, jednocześnie opisano rynek produktów żywnościowych oraz jego wpływ na środowisko naturalne. Ponadto określono w nim problematykę generowania odpadów przez podmioty gospodarcze działające na rynku żywnościowym w aspekcie ich dalszego zagospodarowania. Poruszono, także temat norm sanitarnych dla produktów z sektora gospodarki żywnościowej oraz dynamikę rozwoju technologii wykorzystywanych w procesach logistyki zwrotnej, zmieniających się oczekiwań egzogenicznych i systemów wartości.
Źródło:
Systemy Wspomagania w Inżynierii Produkcji; 2016, 3 (15); 59-69
2391-9361
Pojawia się w:
Systemy Wspomagania w Inżynierii Produkcji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of supply chain management in construction industry
Autorzy:
Nguyen, Phong Thanh
Nguyen, Vi Nguyen
Pham, Luan Hong
Nguyen, Thu Anh
Nguyen, Quyen Le Hoang Thuy To
Huynh, Vy Dang Bich
Powiązania:
https://bibliotekanauki.pl/articles/103168.pdf
Data publikacji:
2018
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
supply chain management (SCM)
limiting factor
construction industry
zarządzanie łańcuchem dostaw
czynnik ograniczający
przemysł budowlany
Opis:
The application of the supply chain management (SCM) in industry has achieved much success, especially in the manufacturing sector. In the current market, the Vietnamese construction companies must compete not only with domestic companies but also with foreign ones, the application of SCM is essential to improve efficiency and increase their competitive advantage. In this paper, a survey was carried out to identify factors that cause limitation in applying SCM to the Vietnamese construction industry. A qualitative approach was based on prime contractor’s perspective at the construction phase of the project. The survey questionnaire was designed by synthesizing and inheriting the previous studies and consultation with experts. The survey participants are those who have had working experience with main contractors and joined in the construction projects. The face-to-face interviews were conducted to collect data. Descriptive statistics analysis and Exploratory Factor Analysis (EFA) were used to analyze data. The results indicated seven leading causes which limited the application of SCM in the construction industry.
Źródło:
Advances in Science and Technology. Research Journal; 2018, 12, 2; 11-19
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Lasso and Elastic-Net Regularized Generalized Linear Model for Predicting Blast-Induced Air Over-pressure in Open-Pit Mines
Model Lasso i uogólniony model liniowy elastycznej siatki do prognozowania nadciśnienia wywołanego wybuchem w kopalniach odkrywkowych
Autorzy:
Bui, Xuan‑Nam
Nguyen, Hoang
Tran, Quang Hieu
Bui, Hoang‑Bac
Nguyen, Quoc Long
Nguyen, Dinh An
Le, Thi Thu Hoa
Pham, Van Viet
Powiązania:
https://bibliotekanauki.pl/articles/318532.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
Lasso model
kopalnia odkrywkowa
wybuchy
open pit mines
explosives
Opis:
Air overpressure (AOp) is one of the products of blasting operations in open-pit mines which have a great impact on the environment and public health. It can be dangerous for the lungs, brain, hearing and the other human senses. In addition, the impact on the surrounding environment such as the vibration of buildings, break the glass door systems are also dangerous agents caused by AOp. Therefore, it should be properly controlled and forecasted to minimize the impacts on the environment and public health. In this paper, a Lasso and Elastic-Net Regularized Generalized Linear Model (GLMNET) was developed for predicting blast-induced AOp. The United States Bureau of Mines (USBM) empirical technique was also applied to estimate blast-induced AOp and compare with the developed GLMNET model. Nui Beo open-pit coal mine, Vietnam was selected as a case study. The performance indices are used to evaluate the performance of the models, including Root Mean Square Error (RMSE), Determination Coefficient (R2), and Mean Absolute Error (MAE). For this aim, 108 blasting events were investigated with the Maximum of explosive charge capacity, monitoring distance, powder factor, burden, and the length of stemming were considered as input variables for predicting AOp. As a result, a robust GLMNET model was found for predicting blast-induced AOp with an RMSE of 1.663, R2 of 0.975, and MAE of 1.413 on testing datasets. Whereas, the USBM empirical method only reached an RMSE of 2.982, R2 of 0.838, and MAE of 2.162 on testing datasets.
Źródło:
Inżynieria Mineralna; 2019, 21, 2/2; 8-20
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in nutrient and heavy metal content levels of sawdust due to vermicomposting by Allomyrina dichotoma subsp. tunobosonis
Autorzy:
Hoang, C.N.
Yang, Z.-W.
Huang, M.-Y.
Lin, K.-H.
Yang, C.-M.
Nguyen, M.K.
Powiązania:
https://bibliotekanauki.pl/articles/81229.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vermicomposting
organic waste
nutrient
heavy metal content
sawdust substrate
Allomyrina dichotoma
beetle
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2019, 100, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Circular transformation of current business solutions in wastewater management
Cykliczna transformacja aktualnych rozwiązań biznesowych w zarządzaniu ściekami
Autorzy:
Czikkely, Marton
Hoang, Nguyen Huu
Fogarassy, Csaba
Powiązania:
https://bibliotekanauki.pl/articles/405190.pdf
Data publikacji:
2019
Wydawca:
Politechnika Częstochowska
Tematy:
conventional linear business models
circular improve
ReSOLVE framework
Mapping analyze
Business Model Canvas
konwencjonalne liniowe modele biznesowe
ramy ReSOLVE
analiza mapowania
osnowa modelu biznesowego
Opis:
The wastewater treatment technologies become more efficiency by biological treatment method business structure development. In this paper, we would like to present a circular economic transformation method to wastewater management development by economical way. The most used wastewater treatment technologies work with conventional business models (by a linear economic way). We determined a circular economic solve to get more effective and cost-efficient wastewater treatment system. The ReSOLVE framework and Mapping method were used and presented the main circular points (in focus of Regenerate part) of each technology to effectively application of treatment solutions. Regarding our research method results, we improved the Business Model Canvas and the main economic transformation points were given by the framework. In this short paper we would like to give answers to how could minimalize the wastewater production by business model development with low cost and effective economical background. The research clearly demonstrates that economic operators and members of the supply chain integrate their resources into circular systems, then business ecosystems can be continually redesigned, creating dynamically and efficiently self-regulating systems. The modern structure of environmental treatment methods does not mean exclusively technological development, the new business structure and innovative circular model could be more useful to rethink the economic loop and cascade solutions. Based on the research results we can almost be sure that the focus of related research will in the future be focused on sharing economy and big data applications.
Technologie oczyszczania ścieków stają się bardziej wydajne dzięki rozwojowi struktury biznesowej metod oczyszczania biologicznego. W tym artykule chcielibyśmy przedstawić ekonomiczną metodę cyklicznej transformacji gospodarczej w rozwoju gospodarki ściekowej. Najczęściej stosowane technologie oczyszczania ścieków działają w oparciu o konwencjonalne modele biznesowe (w sposób liniowy ekonomiczny). Zdecydowaliśmy się na rozwiązanie ekonomiczne o obiegu zamkniętym, aby uzyskać bardziej wydajny i opłacalny system oczyszczania ścieków. Zastosowano szkielet ReSOLVE i metodę mapowania, które przedstawiły główne okrągłe punkty (w części Regenerate) każdej technologii w celu skutecznego zastosowania rozwiązań naprawczych. Jeśli chodzi o wyniki naszych metod badawczych, poprawiliśmy osnowe modelu biznesowego, a główne punkty transformacji gospodarczej zostały określone w ramach. W tym krótkim artykule chcielibyśmy odpowiedzieć na pytanie, w jaki sposób można zminimalizować produkcję ścieków poprzez opracowanie modelu biznesowego z niskim kosztem i efektywnym zapleczem ekonomicznym. Badanie wyraźnie pokazuje, że podmioty gospodarcze i członkowie łańcucha dostaw integrują swoje zasoby w systemy o obiegu zamkniętym, a następnie ekosystemy biznesowe można nieustannie przeprojektowywać, tworząc dynamicznie i skutecznie samoregulujące się systemy. Nowoczesna struktura metod oczyszczania środowiska nie oznacza wyłącznie rozwoju technologicznego, nowa struktura biznesowa i innowacyjny model kołowy mogą być bardziej przydatne do ponownego przemyślenia pętli ekonomicznej i rozwiązań kaskadowych. Na podstawie wyników badań możemy być prawie pewni, że badania pokrewne będą w przyszłości koncentrować się na udostępnianiu aplikacji ekonomicznych i dużych zbiorów danych.
Źródło:
Polish Journal of Management Studies; 2019, 20, 2; 196-209
2081-7452
Pojawia się w:
Polish Journal of Management Studies
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:
Subjective risk estimation of the rare event
Autorzy:
Nguyen, Hoang
Powiązania:
https://bibliotekanauki.pl/articles/241939.pdf
Data publikacji:
2019
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
rare event
subjective risk estimation
intuitionistic fuzzy set
ship propulsion risk
Opis:
In the safety engineering, the most frequently disadvantage in risk estimation is the lack of data. In such cases, we have to rely on subjective estimations made by persons with practical knowledge in the field of interest, i.e. experts. However, in some realistic situations, they may have uncertainty in the perceiving and evaluation of the problem considered or limited knowledge of the rare events, such as the consequences of the seagoing ship propulsion failures. The probabilistic models of the risk estimation turn out to be insufficient in modelling the subjective uncertainty. The fuzzy methods are viewed to be powerful in dealing with ambiguity and uncertainty that can be used to handle with the subjective estimation. This article addresses the intuitionistic fuzzy method in the subjective estimation of the ship propulsion failure consequences as rare event risk. In the article, a subjective model of the ship propulsion risk is developed as scenarios of the different subsequent consequences of loss of ship propulsion function until a seriously severe accident resulting in loss of seaworthiness. The model proposes an approach combining AHP method and intuitionistic fuzzy method to assess the occurrence probability and severe probability of these rare events based on the expert opinions. In order to show the applicability of the proposed model, a study case of the propulsion risk of the container carrier operating on the North Atlantic lines is conducted.
Źródło:
Journal of KONES; 2019, 26, 1; 103-110
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of Unmanned Aerial Vehicles for 3D topographic Mapping and Monitoring the Air Quality of Open-pit Mines
Wykorzystanie bezzałogowych statków powietrznych (dronów) do monitorowania jakości powietrza w odkrywkowych kopalniach węgla kamiennego
Autorzy:
Bui, Xuan‑Nam
Lee, Changwoo
Nguyen, Quoc Long
Adeel, Ahmad
Cao, Xuan Cuong
Nguyen, Viet Nghia
Le, Van Canh
Nguyen, Hoang
Le, Qui Thao
Duong, Thuy Huong
Nguyen, Van Duc
Powiązania:
https://bibliotekanauki.pl/articles/317913.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
drony
jakość powietrza
kopalnie odkrywkowe
unmanned aerial vehicles
air quality
open pit mines
Opis:
Recently remarkable advancement development of unmanned aerial vehicles (UAVs) has been observed and their applications have been shown in many fields such as agriculture, industry, and environmental management. However, in the mining industry, the application of UAV technology remains potential. This paper presents a low-cost unmanned aerial vehicle technology-based system for 3D mapping and air quality monitoring at open-pit mine sites in Vietnam. The system includes several dust sensors that are mounted on a low-cost rotary-wing type UAV. The system collects a variety of data, mainly images and airborne pollutant concentrations. To evaluate the performance of the proposed system, field tests were carried out at the Coc Sau coal mine. Based on the images transmitted to the ground monitoring station, large scale 3D topographic maps were successfully modeled. In addition, sensors mounted on the UAV system were able to monitor the levels of environmental variables associated with the air quality within the pit such as temperature, dust, CO, CO2, and NOx. The field test results in this study illustrate the applicability of the low-cost UAV for the 3D mapping and the air quality monitoring at large and deep coal pits with relatively high accuracy.
Źródło:
Inżynieria Mineralna; 2019, 21, 2/2; 223-239
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of behaviour of the steel arch support in the geological and mining conditions of the Cam Pha coal basin, Vietnam
Autorzy:
Nguyen, Phu Minh Vuong
Rotkegel, Marek
Van, Hoang Do
Powiązania:
https://bibliotekanauki.pl/articles/1853833.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
podpora stalowa
analiza numeryczna
górnictwo wietnamskie
steel arch support
profiles of steel arch support
numerical analysis
Vietnamese coal mining industry
Opis:
In recent years, the Vietnamese coal mining industry has observed a dynamic increase in both its production and efficiency. In Vietnam, the most precious type of coal is anthracite, which is found in the Quang Ninh province. Industrial anthracite deposits are estimated to be over 2 billion Mg. At present, coal deposits are extracted mostly by the underground method. Coal production is gradually increasing in the underground mines in the Quang Ninh area and it is expected to constitute about 75% of the country’s total coal production in 2030. This involves an increase in the number and length of underground workings. Cam Pha is the largest coal basin of Vietnam, located in the Quang Ninh province. So far, the yearly length of underground workings driven in underground mines in the Cam Pha basin is roughly 90÷150 km. About 84 % of these underground workings are supported by the steel arch support made of SWP profile. A similar situation can be observed in Russia, Ukraine, China, India and Turkey. In addition, the average length of repaired underground workings in the Cam Pha basin constitutes approximately 30% of the total length driven . The main cause was reported is loss of underground workings stability. This requires significant material and labour costs as well as the cost of replacing damaged elements. Addi-tionally, it disturbs the continuity of the mining operations.This article presents the results of the numerical modelling of the rock mass around underground wor-kings driven in typical geo-mining conditions for underground coal mines in the Cam Pha basin, supported by the steel arch support made of SWP and V profiles. As a result of the conducted analyses, the range of failure zone of the rock mass around underground workings and the distribution of reduced stress in the steel arch support elements were determined. The effort states of the steel arch support made of SWP22 profile and V21 profile were compared. The simulations considered different inclinations angle of coal seam, following the structure of the rock mass in the Cam Pha basin. The analysis was carried out using the based-finite difference method code, FLAC2D. Based on the obtained results, actions for improving the stability of underground workings driven in the underground mines of the Cam Pha basin were proposed.
Źródło:
Archives of Mining Sciences; 2020, 65, 3; 551-567
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Front Stress Distribution Under the Impact of Cutting Height to Caving Height Ratio in Extra- -thick Longwall Top Coal Caving Technology
Badanie nad rozkładem naprężeń przed ścianą gdy stosunek urabiania do odzyskania zmienia się w eksploatacji długich ścian przy bardzo grubych pokładach
Autorzy:
Bui, Manh Tung
Nguyen, VanQuang
Nguyen, Phi Hung
Vo, Ngoc Dung
Do, Hoang Hiep
Powiązania:
https://bibliotekanauki.pl/articles/319219.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
extra-thick seam
extra-cutting height
cutting/caving height ratio
stress distribution
bardzo gruby pokład
duża wysokość urabiania
stosunek wysokości urabiania/ odzyskania
rozkład naprężeń
Opis:
The extraction with higher cutting height for extra-thick seam is the new research orientation in longwall caving technology. Due to the increase of top coal thickness and of cutting height which leads to the change of cutting/caving height ratio, the rule of roof failure (including top coal caving) and the distribution of stress around the face alter correspondingly. This paper is based on the geological conditions of face 8102 of Tashan-DaTong mine, employing the numerical model by UDEC2D code, analysing the effect of cutting/ caving height ratio on the law of stress distribution ahead of the face. When the ratio of cutting/caving height decreases and the cutting height increases, the results of the research have shown that: (i)- peak stress redistributes further ahead of the face and its value manifestly drops; (ii)- the plastic deformation ahead of face significant increases and the zone of plastic strain also expands. It is therefore concluded that the variation of cutting/caving height ratio results in the redistribution of roof pressure, which contributes to the control of roof failure and face stability.
Przy bardzo grubych pokładach, eksploatacja z dużą wysokością to nowy kierunek badań w technologii zawału stropu węgla. Ze względu na grubość warstwy stropu węglowego i zwiększoną wysokość urabiania prowadzi do zmiany stosunku urabiania do odzyskania, co również zmienia regułę zapalenia skał stropowych i zmienia stan rozkładu naprężeń wokół ściany. W artykule, przedstawiono wyniki analizy wpływu stosunku urabiania do uzyskania opierając się na prawie rozkładu obciążenia przed ścianą. Analiza ta została oparta na warunkach geologicznych kopalni 8102 TaSan-DaTong wykorzystując model numeryczny UDEC2D. Wyniki badań pokazują, że wraz ze spadkiem stosunku urabiania do odzyskania, oznacza to wzrost wysokości urabiania, położenie maksymalnego naprężenia jest daleko od ściany, maksymalna wartość naprężeń znacznie spada, zniszczenie plastyczne przed ścianą i stropem gwałtownie rośnie, zwiększa się strefa odkształcenia plastycznego. Dlatego zmiana stosunku urabiania do odzyskania może zmienić stan rozkładu ciśnienia stropowego, co jest korzystne dla procesu niszczenia stropu i kontrolowania stabilności ściany.
Źródło:
Inżynieria Mineralna; 2020, 1, 2; 123-129
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of macro economic factors and financial development on energy projects - case in ASEAN countries
Autorzy:
Hanh, Hoang Thanh
Huy, Dinh Tran Ngoc
Phuong, Nguyen Thi Thanh
Nga, Le Thi Viet
Anh, Pham Tuan
Powiązania:
https://bibliotekanauki.pl/articles/1818318.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Wydział Ekonomii i Zarządzania
Tematy:
countries ASEAN
commerce
financial development
energy project
macroeconomic
macro politicies
kraje ASEAN
handel
rozwój finansowy
projekty energetyczne
makroekonomia
makropolityka
Opis:
ASEAN (The Association of SouthEast Asian Nations) demand on energy is depending on economic growth of each country, resources, and political and regulations of each country. This study aims to investigate the role of international trade, financial development, foreign direct investment (FDI) on the consumption of renewable energy (RE) in ASEAN countries of the world. The findings explore that positive nexus among the international trade, real output, financial development, foreign direct investment and consumption of RE. Last but not least, this paper will propose several recommendations and policy suggestion for ASEAN countries to manage and encourage better renewable energy projects in the region. One of its original value is that, in the globalization and integration era, environment pollution will affect all ASEAN countries and in the region, so these nations need to link together to implement renewable projects for environment protection and for further generation.
Źródło:
Management; 2020, 24, 2; 146-157
1429-9321
2299-193X
Pojawia się w:
Management
Dostawca treści:
Biblioteka Nauki
Artykuł
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