Autor: Nguyen, Van Duc - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Methods to Estimate the Channel Delay Profile and Doppler Spectrum of Shallow Underwater Acoustic Channels
Autorzy:: Nguyen, Van Duc
Nguyen, Tien Hoa
Ho, Hoa Xuan Thi
Powiązania:: https://bibliotekanauki.pl/articles/176670.pdf
Data publikacji:: 2019
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:: shallow underwater acoustic
channel parameters detection
channel delay profile
Doppler spectrum
Opis:: In this paper, we present the methods to detect the channel delay profile and the Doppler spectrum of shallow underwater acoustic channels (SUAC). In our channel sounding methods, a short impulse in form of a sinusoid function is successively sent out from the transmitter to estimated the channel impulse response (CIR). A bandpass filter is applied to eliminate the interference from out-of-band (OOB). A threshould is utilized to obtain the maximum time delay of the CIR. Multipath components of the SUAC are specified by correlating the received signals with the transmitted sounding pulse with its shifted phases from 0 to 2π. We show the measured channel parameters, which have been carried out in some lakes in Hanoi. The measured results illustrate that the channel is frequency selective for a Barrow band transmission. The Doppler spectrum can be obtained by taking the Fourier transform of the time correlation of the measured channel transfer function. We have shown that, the theoretical maximum Doppler frequency fits well to that one obtained from measurement results.
Źródło:: Archives of Acoustics; 2019, 44, 2; 375-383
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 2.

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

Zmień widok

na półce

Skocz do pozycji: 3.

Tytuł:: Delay factors in the construction of irrigation and hydropower projects in Vietnam
Autorzy:: Nguyen, Van Son
Nguyen, Huu Hue
Nguyen, Duc Anh
Hai, Dinh Tuan
Powiązania:: https://bibliotekanauki.pl/articles/2203414.pdf
Data publikacji:: 2023
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: hydroenergetyka
nawadnianie
konstrukcja
zarządzanie projektem
współczynnik opóźnienia
Wietnam
hydropower
irrigation
construction
project management
delay factor
Vietnam
Opis:: Irrigation and hydropower are among the most important sectors in the construction industry that propel the economic needs of a developing country like Vietnam. The construction of these projects often suffers from severe delays, leading to financial losses and other negative impacts on the economy. This paper aims to determine delay factors in the construction of these projects. Among many, 39 most important candidates of delay causes were identified from the literature review. Further surveys on project participants were conducted for the severity of these causes. An exploratory factor analysis was utilized to identify latent factors that cause delays in construction projects. The analysis result categorized a few groups of factors such as abnormal factors on the construction site (e.g., labor accidents, hydrology, water flow, extreme weather) and technical factors related to the construction contractor (e.g., unsuitable schedule, outdated construction technology, unprofessional workers) that have the greatest impact on the delay in construction of irrigation and hydropower projects in Vietnam. These findings contribute to the body of knowledge of project management and risk management, hence an improvement in the efficiency of the project sectors’ performance.
Źródło:: Archives of Civil Engineering; 2023, 69, 1; 5--20
1230-2945
Pojawia się w:: Archives of Civil Engineering
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 4.

Tytuł:: Robust H∞ fuzzy approach design via Takagi‐Sugeno descriptor model. application for 2‐DOF serial manipulator tracking control
Autorzy:: Thi, Van Anh Nguyen
Pham, Duc Binh
Nguyen, Danh Huy
Nguyen, Tung Lam
Powiązania:: https://bibliotekanauki.pl/articles/27314207.pdf
Data publikacji:: 2022
Wydawca:: Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:: tracking control
serial manipulator robot
fuzzy control
Takagi-Sugeno
Lyapunov stability
Opis:: This paper focuses on trajectory tracking control for ro‐ bot manipulators. While much research has been done on this issue, many other aspects of this field have not been fully addressed. Here, we present a new solution using feedforward controller to eliminate parametric uncer‐ tainties and unknown disturbances. The Takagi‐Sugeno fuzzy descriptor system (TSFDS) is chosen to describe the dynamic characteristics of the robot. The combination of this fuzzy system and the robust H∞ performance makes the system almost isolated from external factors. The li‐ near matrix inequalities based on the theory of Lyapunov stability is considered for control design. The proposed method has proven its effectiveness through simulation results.
Źródło:: Journal of Automation Mobile Robotics and Intelligent Systems; 2022, 16, 3; 22--29
1897-8649
2080-2145
Pojawia się w:: Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 5.

Tytuł:: Multi-objective optimization of the cylindrical grinding process of SCM440 steel using preference selection index method
Autorzy:: Tien, Dung Hoang
Trung, Do Duc
Thien, Nguyen Van
Nguyen, Nhu-Tung
Powiązania:: https://bibliotekanauki.pl/articles/1833757.pdf
Data publikacji:: 2021
Wydawca:: Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
Tematy:: MRR
Taguchi PSI method
surface roughness
cylindrical grinding process
Opis:: This paper presents a study to ensure the minimum values of Ra and Rz, and the maximum value of MRR when external cylindrical grinding by the PSI method. The experiments were performed according to the orthogonal Taguchi L9 matrix with the input parameters including workpiece speed, feed rate, and depth of cut in the conventional grinding machine. Analysis of experimental results by Pareto chart showed that the feed rate and the depth of cut most influence on Ra and Rz, respectively. Feed rate and depth of cut all have a great influence on MRR. Meanwhile, the workpiece speed has a negligible effect on all three output parameters. The research results showed that to obtain the minimum values of Ra and Rz, and maximum of MRR, the workpiece speed, feed rate, and depth of cut were 400 rev/min 37.7 mm/min, 0.09 mm/rev, and 0.02 mm, respectively.
Źródło:: Journal of Machine Engineering; 2021, 21, 3; 110--123
1895-7595
2391-8071
Pojawia się w:: Journal of Machine Engineering
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 6.

Tytuł:: The Impact of Digital Leadership on Organizational Performance: A Study in Vietnams coal Mining Companies
Autorzy:: Le, Van Chien
Nguyen, Duc Thang
Pham, Kien Trung
Nguyen, Thi Hoai Nga
Powiązania:: https://bibliotekanauki.pl/articles/27323234.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Przeróbki Kopalin
Tematy:: digital transformation
digital leadership
digital transformation strategy
digital skills
organization performance
coal mining company
transformacja cyfrowa
strategia
górnictwo
Opis:: Under the influence of the 4th industrial revolution and the impact of the Covid-19 pandemic, digital transformation is rapidly taking place in all aspects of society. For businesses, digital transformation is an essential and objective trend for their sustainability and development. The purpose of digital transformation for businesses is to enhance operational efficiency through factors such as accelerating market speed, gaining competitive advantage, driving revenue growth, increasing labor productivity, and expanding customer attraction and retention. Numerous studies have indicated that the process of digital transformation in businesses is influenced by leadership and digital transformation strategies, and digital transformation has an impact on business performance. This study aims to identify the relationship between digital leadership and the operational efficiency of coal mining companies in Vietnam, with the mediating role of digital transformation strategies. Additionally, the study examines the moderating role of digital skills on the relationship between digital transformation strategies and the operational efficiency of the organizations. The research surveyed 111 employees and workers currently working in coal mining companies in Vietnam. Through analysis and hypothesis testing, the results showed that digital leadership does not have a direct impact on coal companies’ operational efficiency. However, it indirectly affects business performance through the mediating role of digital transformation strategies. The study's findings also revealed that the digital skills of employees play a moderating role in enhancing the relationship between digital transformation strategies and the operational efficiency of the organization.
Źródło:: Inżynieria Mineralna; 2023, 2; 121--130
1640-4920
Pojawia się w:: Inżynieria Mineralna
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 7.

Tytuł:: Applying Artificial Pillar to Replace the Coal Pillar Protecting Roadway to Increase Production Efficiency and Sustainable Development in the Vietnamese Coal Industry
Autorzy:: Dinh, Van Cuong
Nguyen, Anh Tuan
Tran, Van Thanh
Nguyen, Thi Hoai Nga
Duong, Duc Hai
Powiązania:: https://bibliotekanauki.pl/articles/2020898.pdf
Data publikacji:: 2021
Wydawca:: Polskie Towarzystwo Przeróbki Kopalin
Tematy:: coal pillar protecting roadways
coal loss
artificial pillar
underground mine
filary węglowe
górnictwo podziemne
ubytki węgla
Opis:: Vietnam's domestic coal production is growing fast and is expected to reach 68.9 million tons in 2030, nearly 1.5 times higher than today. Open-pit mines will gradually reduce production and close, and underground mining coal output will increase progressively year by year and take a leading role. Besides the investment in new mines to achieve these goals, it is necessary to maximize the coal reserve exploited annually of existing underground mine projects, which its coal reserve in pillars protecting roadways currently accounts for 12−15%. The further exploitation of this coal reserve will decrease the costs of preparation of underground mines and granting mining rights and depreciation of infrastructure assets. Moreover, it will help reduce the loss of non-renewable resources and contributing to the sustainable development of Vietnam’s coal industry.
Źródło:: Inżynieria Mineralna; 2021, 2; 587--597
1640-4920
Pojawia się w:: Inżynieria Mineralna
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 8.

Tytuł:: Assessment of Heavy Metal Pollution in the Surface Water of the Doi-Cho Dem-Ben Luc Rivers, Vietnam
Ocena zanieczyszczenia metalami ciężkimi wód powierzchniowych rzek Doi-Cho Dem-Ben Luc w Wietnamie
Autorzy:: Thieu, Van Vu Duc
Dinh, Thi Thu Huong
Nguyen, Thi Truc Thao
Nguyen, Thuy Lan Chi
Nguyen, Binh An
Pham, Anh-Duc
Powiązania:: https://bibliotekanauki.pl/articles/2172069.pdf
Data publikacji:: 2022
Wydawca:: Polskie Towarzystwo Przeróbki Kopalin
Tematy:: heavy metal pollution
surface water
distribution
river
Doi-Cho Dem-Ben Luc
water quality protection
zanieczyszczenie metalami ciężkimi
wody powierzchniowe
dystrybucja
rzeki
ochrona jakości wód
Opis:: Heavy metals are a pressing concern in terms of their pollution in aquatic ecosystems because of their persistence, environmental toxicity, bioaccumulation. Aquatic environments receive heavy metals in untreated or inadequately treated wastewater from domestic, industrial, agricultural, and navigation sources. The Doi-Cho Dem-Ben Luc Rivers play the key roles of irrigation, navigation and ecological restoration. It is crucial to ascertain the pollution status, influencing factors, ecological risks, and possible sources of heavy metals in the surface water of the Doi-Cho Dem-Ben Luc Rivers. In this study, surface water from 7 sampling sites over was collected from the Doi-Cho Dem-Ben Luc Rivers, over 7 consecutive periods from April 2019 to October 2021. Each surface sample was analyzed for 9 heavy metals including Fe, Mn, Cr, Zn, Cu, Pb, Cd, Ni, As. The sampling technique and sample treatment were done based on the Standard Methods for the Examination of Water and Wastewater. The time and space variation of heavy metal concentrations were examined to test the analysis of variance (ANOVA) and correlation among all the parameters using R statistical software. The results suggest a spatial homogeneity of heavy metals in the surface water the studied rivers. Among all nine examined heavy metals in the studied area, the concentrations of Fe (1.00 ÷ 5.06 mg/L) and Mn (0.14 ÷ 0.28 mg/L) are the highest, and the concentrations of Cr, Cd and As are the lowest that lower limit of detection. The results suggested that the mean concentrations of Fe and Mn were above the acceptable limits of the National technical regulation on surface water quality (QCVN 08-MT: 2015/BTNMT). While the concentrations of Fe, Mn, Zn, Cu, Pb, Ni do not meet the Water quality criteria for aquatic life (United State Environmental Protection Agency). Anthropogenic activities can be the main source of heavy metals in in the surface water of the Doi-Cho Dem-Ben Luc Rivers. Among the heavy metals, a significant positive correlation was observed between Fe, Mn, Zn and Ni (0.64 ÷ 0.87), whereas Cu exhibited a significant positive correlation with Ni (0.51). While Cu and Pb showed a not too strong correlation with Fe, Mn, Zn and Ni (0.25 ÷ 0.48). The distribution of heavy metals may also be influenced by properties of heavy metals and fluctuations in water flows. The results provide guidance for controlling heavry metal pollution and protectting water sources in the Doi-Cho Dem-Ben Luc Rivers.
Metale ciężkie stanowią palący problem zanieczyszczenia w ekosystemach wodnych ze względu na ich trwałość, toksyczność dla środowiska i bioakumulację. Środowiska wodne sa zasilane w metale ciężkie z nieoczyszczonych lub nieodpowiednio oczyszczonych ścieków ze źródeł domowych, przemysłowych, rolniczych i żeglugowych. Rzeki Doi-Cho Dem-Ben Luc odgrywają kluczową rolę w nawadnianiu terenów, transporcie odnym i odbudowie ekologicznej. Kluczowe znaczenie ma ustalenie stanu zanieczyszczenia, czynników wpływających, zagrożeń ekologicznych i możliwych źródeł metali ciężkich w wodach powierzchniowych rzek Doi-Cho Dem-Ben Luc. W artykule przedstawiono wyniki badania wód powierzchniowych, próbki pobrano z 7 punktów pomiarowych z rzek Doi-Cho Dem-Ben Luc przez 7 kolejnych okresów od kwietnia 2019 r. do października 2021 r. Każda próbka została przeanalizowana pod kątem zawartości 9 metali ciężkich: Fe, Mn, Cr , Zn, Cu, Pb, Cd, Ni, As. Metodyka pobierania próbek i obróbki próbek zostały opracowane w oparciu o Standardowe Metody Badania Wód i Ścieków. Zbadano zmienność w czasie i przestrzeni stężeń metali ciężkich, do analizyy wyników wykorzystano analizę wariancji (ANOVA) i korelacji między wszystkimi parametrami przy użyciu oprogramowania statystycznego. Wyniki sugerują przestrzenną jednorodność zawartości metali ciężkich w wodach powierzchniowych badanych rzek. Spośród wszystkich dziewięciu badanych metali ciężkich w badanym terenie najwyższe są stężenia Fe (1,00 ÷ 5,06 mg/L) i Mn (0,14 ÷ 0,28 mg/L), a najniższe Cr, Cd i As (wartości odpowiadające dolnej granicy wykrywalności). Wyniki wskazują, że średnie stężenia Fe i Mn były powyżej dopuszczalnych limitów, opisanych w krajowych normach dotyczących jakości wód powierzchniowych (QCVN 08-MT: 2015/BTNMT). Natomiast stężenia Fe, Mn, Zn, Cu, Pb, Ni nie spełniają kryteriów jakości wody dla organizmów wodnych (Agencja Ochrony Środowiska Stanów Zjednoczonych). Działalność antropogeniczna może być głównym źródłem metali ciężkich w wodach powierzchniowych rzek Doi-Cho Dem-Ben Luc. Wśród metali ciężkich zaobserwowano istotną dodatnią korelację między zawartością Fe, Mn, Zn i Ni (0,64 ÷ 0,87), natomiast Cu wykazywała istotną dodatnią korelację z Ni (0,51). Zawartości Cu i Pb wykazywały niezbyt silną korelację z Fe, Mn, Zn i Ni (0,25 ÷ 0,48). Na rozmieszczenie metali ciężkich mogą mieć również wpływ właściwości metali ciężkich oraz wahania przepływów wody. Wyniki dostarczają wskazówek dotyczących kontrolowania zanieczyszczenia metalami ciężkimi i ochrony źródeł wody w rzekach Doi-Cho Dem-Ben Luc.
Źródło:: Inżynieria Mineralna; 2022, 2; 85--90
1640-4920
Pojawia się w:: Inżynieria Mineralna
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 9.

Tytuł:: Radon-Radium Thermal Mineral Water in Vo Am Ecotourism Project Area, Ngoc Luong Commune, Yen Thuy District, Hoa Binh Province, Vietnam
Autorzy:: Ban, To Xuan
Dung, Le Tien
Duc, Tran Van
Trong, Nguyen Huu
Tuan, Truong Duc
Powiązania:: https://bibliotekanauki.pl/articles/27323255.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Przeróbki Kopalin
Tematy:: thermal mineral water
Ngoc Luong
Hoa Binh
Vietnam
wody termalne
wody mineralne
Wietnam
Opis:: Ngoc Luong thermal mineral water at Vo Am ecotoursim, Ngoc Luong commnune, Yen Thuy district, Hoa Binh province, northern Vietnam. The thermal mineral water source is at karstic-fractured limstones of Dong Giao Formation aged Anisi. Methods used in this study conists of basic field survey of hydrogeology, resistivity, borehole drilling, pumping tests, and thermal mineral water sample analysis. The thermal mineral water is classified as radon-radium, low mineralised thermal mineral water. The water source is originally related to the deep Moc Chau-Tam Diep Fault directing northwest-southeastward. Its exploration reserve is estimated at 1,497 m3/d with good quality, sastifying all national criterals for the use of domestic supply, bathing, and medical treatment. This is one of ten rare thermal-mineral water sources in Vietnam, containing radon and radium. It is thefore necessary to have good management to ensure the thermal-mineral water to be effectively exploited, used, and protected.
Źródło:: Inżynieria Mineralna; 2023, 2; 327--333
1640-4920
Pojawia się w:: Inżynieria Mineralna
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 10.

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

Zmień widok

na półce

Informacja

Wyszukujesz frazę "Nguyen, Van Duc" wg kryterium: Autor

Źródło danych

Dostawca treści

Kolekcja

Rok wydania

Wydawca

Temat

Autor

Typ dokumentu

Język