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Wyszukujesz frazę "Nguyen, Vu" wg kryterium: Autor


Tytuł:
Identification of the heat source and thermal material model parameters for the laser engineered net shaping
Autorzy:
Hajder, Lucyna
Zhang, Tao
Nguyen, Vu
Powiązania:
https://bibliotekanauki.pl/articles/29520077.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
additive manufacturing
finite element analysis
heat source model
thermal analysis
Opis:
The research’s primary goal is to identify the heat source and thermal material model parameters for the numerical simulation of the laser engineered net shaping (LENS). Inconel 718 was selected as a case study for the current investigation. The LENS process’s numerical model was developed within commercial finite element software and was used as a direct problem model during the parameter identification stage. Experimental data were obtained based on a rectangular-shaped sample with thermocouples located under the based material surface. The recorded thermal profiles were used to establish a goal function for the parameter identification stage. As a result, parameters describing the melt pool geometry during the additive manufacturing, as well as thermal coefficients describing interactions between the sample material and surrounding/base material, were determined.
Źródło:
Computer Methods in Materials Science; 2022, 22, 1; 43-54
2720-4081
2720-3948
Pojawia się w:
Computer Methods in Materials Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupling Satellite Images and Unmanned Aerial Vehicle Data to Monitor the Exploitation of Open-Pit Mine
Łączenie zdjęć satelitarnych i danych bezzałogowego statku powietrznego w celu monitorowania eksploatacji kopalni odkrywkowej
Autorzy:
Tong, Si Son
Le, Quang Toan
Vu, Phan Long
Pham, Thi Lan
Ha, Le Thi Thu
Tong, Thi-Huyen-Ai
Nguyen, Vu Giang
Powiązania:
https://bibliotekanauki.pl/articles/318465.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
land cover dynamic
open-pit mine
UAV
stages of exploitation
dynamika zmienna terenu
kopalnia odkrywkowa
bezzałogowy statek powietrzny
etapy eksploatacji
Opis:
Discovering the variation of an open-pit mine in vertical, horizontal, and temporal dimensions as well to characterize the stages and the trends of the exploitation are indispensable tasks which provide information supporting decision making and planning for sustainable development of the mining industry. Remote sensing technique with the advantages of multi-spatial, multi-spectral, multi-temporal resolution is a promising solution to meet the information requirement. This study proposes an approach of coupling the high-resolution satellite images and Unmanned Aerial Vehicle (UAV) data to observe the variation of Tan An open rocky mine during its lifetime. Five satellite images with the resolution of 0.5 m acquired in 2006, 2012, 2014, 2016, 2018, and two ortho-images with 0.034 m resolution constructed from UAV photos captured in 2019, 2020 are used to make land cover maps. The analysis of land cover changes discovers 3 stages of open-pit mine exploitation consisting of unprompted exploitation, exploiting outbreak and stable exploitation corresponding to the changes in the mine. Besides, two Digital Surface Models (DSM) constructed by UAV photos are compared to calculate the elevation and volume changes. The assessment of the correlation between elevation change and land cover change indicates that the mineral exploitation is in the vertical range from 645 m to 660 m, and the exploitation trend is following the horizontal expansion rather than the deep excavation. Additionally, this experiment results in 79,422 m3 of mineral taken from the mine, and 34,022 m3 of soil used for the restoration within a year from June 2019 to June 2020.
Monitorowanie zmienności kopalni odkrywkowej w wymiarze pionowym, poziomym i czasowym oraz scharakteryzowanie etapów i trendów eksploatacji są niezbędnymi zadaniami niezbędnymi do dostarczenia informacji wspomagających podejmowanie decyzji i planowanie zrównoważonego rozwoju górnictwa. Technika teledetekcji z zaletami wieloprzestrzennej, wielospektralnej, wieloczasowej rozdzielczości jest obiecującym rozwiązaniem spełniającym powyższe wymaganie. Niniejsze badanie proponuje podejście po-legające na połączeniu obrazów satelitarnych o wysokiej rozdzielczości i danych z bezzałogowego statku powietrznego (BSP) w celu obserwacji zmian w otwartej kopalni skalnej Tan An w czasie jej życia. Pięć zdjęć satelitarnych o rozdzielczości 0,5 m, pozyskanych w latach 2006, 2012, 2014, 2016, 2018 oraz dwa ortofotomapy o rozdzielczości 0,034 m wykonane ze zdjęć BST wykonanych w 2019, 2020 r. Są wykorzystywane do tworzenia map pokrycia terenu. Analiza zmian pokrycia terenu ujawnia 3 etapy eksploatacji kopalni odkrywkowej, na które składają się: eksploatacja niezamówiona, ognisko eksploatacyjne oraz etapy stabilnej eksploatacji odpowiadające zmianie pokrycia terenu w kopalni. Ponadto porównuje się dwa modele numeryczne powierzchni (MNP) zbudowane na podstawie zdjęć BSP, aby obliczyć wysokość i zmiany objętości kopalni. Ocena korelacji między zmianą wysokości a zmianą pokrycia terenu wskazuje, że eksploatacja kopaliny mieści się w przedziale od 645 m do 660 m npm, a trend eksploatacji raczej według ekspansji poziomej niż metodą wydobywczą. Dodatkowo, w wyniku tego doświadczenia uzyskano 79 422 m3 gruntów pobranego z kopalni oraz 34022 m3 gruntów użytej do rekultywacji w ciągu roku od czerwca 2019 do czerwca 2020.
Źródło:
Inżynieria Mineralna; 2020, 1, 2; 291-299
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sandy Soil Reclamation Using Biochar and Clay-Rich Soil
Autorzy:
Thi, Diep Pham
Hang, Nga Nguyen Thi
Viet, On Tran
Van, Loc Nguyen
Viet, Anh Nguyen
Lan, Phuong Dinh Thi
Van, Nguyen Vu
Powiązania:
https://bibliotekanauki.pl/articles/1838287.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
sandy soil
biochar
clay-rich soil
physical properties
chemical properties
Opis:
The investigations on the effects of biochar application in improving the physio-chemical properties of soil have been carried out in many studies; however, there are very few studies on the combined use of both biochar and clay-rich soil for poor nutrient soil reclamation. Therefore, this study demonstrates improved water retention and nutrient retention of sandy soil by using biochar and biochar combined with clay-rich soil. The experiments were conducted on a small scale (greenhouse) with nine different application rates of biochar and clay-rich soil were mixed and then cultivated peanut, along with the drip irrigation technique using field moisture limit (about 70-80%) was applied under the condition of ensuring a sufficient supply of NPK for plant’s growth. The results showed that at the rates from 10.0-15.0% (w/w) clay-rich soil mixed with from 0.5-1.5% (w/w) of biochar applied to the tested sandy soil resulted in the positive effects on soil water holding, bulk density, permeability, pH, CEC, OM, total N, total P and peanut yield. The physical and chemical characteristics of the tested sandy soil have been improved by time and the application rate of 10.0% clay-rich soil and 0.5% biochar had the highest efficiency of pod fresh weight and pod dry weight during three studied seasons.
Źródło:
Journal of Ecological Engineering; 2021, 22, 6; 26-35
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sandy Soil Reclamation Using Biochar and Clay-Rich Soil
Autorzy:
Thi, Diep Pham
Hang, Nga Nguyen Thi
Viet, On Tran
Van, Loc Nguyen
Viet, Anh Nguyen
Lan, Phuong Dinh Thi
Van, Nguyen Vu
Powiązania:
https://bibliotekanauki.pl/articles/1838394.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
sandy soil
biochar
clay-rich soil
physical properties
chemical properties
Opis:
The investigations on the effects of biochar application in improving the physio-chemical properties of soil have been carried out in many studies; however, there are very few studies on the combined use of both biochar and clay-rich soil for poor nutrient soil reclamation. Therefore, this study demonstrates improved water retention and nutrient retention of sandy soil by using biochar and biochar combined with clay-rich soil. The experiments were conducted on a small scale (greenhouse) with nine different application rates of biochar and clay-rich soil were mixed and then cultivated peanut, along with the drip irrigation technique using field moisture limit (about 70-80%) was applied under the condition of ensuring a sufficient supply of NPK for plant’s growth. The results showed that at the rates from 10.0-15.0% (w/w) clay-rich soil mixed with from 0.5-1.5% (w/w) of biochar applied to the tested sandy soil resulted in the positive effects on soil water holding, bulk density, permeability, pH, CEC, OM, total N, total P and peanut yield. The physical and chemical characteristics of the tested sandy soil have been improved by time and the application rate of 10.0% clay-rich soil and 0.5% biochar had the highest efficiency of pod fresh weight and pod dry weight during three studied seasons.
Źródło:
Journal of Ecological Engineering; 2021, 22, 6; 26-35
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The contribution of geophysics to archaeology: a case study of an ancient canal of the Oc Eo culture in the Mekong Delta, Vietnam
Autorzy:
Le, Ngoc Thanh
Nguyen, Quang Dung
Nguyen, Quang Bac
Nguyen, Quang Mien
Nguyen, Dan Vu
Duong, Ba Man
Nguyen, Dinh Chau
Powiązania:
https://bibliotekanauki.pl/articles/184367.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
electromagnetic profiling
electrical resistivity tomography
hand-auger
radiocarbon dating
ancient canal
alluvial deposits
Oc Eo culture
Ba The mountain
Opis:
Generally, underground ancient canals are infilled with alluvial materials, with the canal bed and substrate often having different resistivity values. This study aimed to determine the location and morphology of Malleret’s ancient canal 16 located to the southeast of the Ba The mountain, Mekong Delta, Vietnam by means of geophysical techniques. Two geophysical methods were used: electromagnetic profile and electric resisitivity tomography. A geoelectric structure 70 m long with 70–95 mS/m of apparent conductivity was found. On the electrical resistivity tomography section, a resistivity zone of 10–20 Ω∙m, 1–4 m deep, 70 m wide corresponds to the mentioned above geoelectric structure, which is in an asymmetric U-shape extending toward the southeastern bank of canal 16. Hand-augering confirmed that the canal bed is fully incised into Holocene sediments as a substrate which stretches down to the Pleistocene. The sediments are composed of loams mixed with plant remains with a resistivity ρ ~ 10–15 Ω∙m. Both of the canal banks at a depth of 5 m are made up of Holocene sedi-ments (ρ ~ 4–10 Ω∙m). The 14C measurements determined the age of the organic matter in the canal as being equal to 1210 ±85 BP, suggesting canal 16 ceased being operational at that time. The precise positioning of canal 16 on the ground surface, as well as identifying the morphology of the canal bed, were corroborated by geophysical techniques. The obtained results are of considerable value to archaeologists.
Źródło:
Geology, Geophysics and Environment; 2019, 45, 1; 45-56
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
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:
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:
Applying Electrical Impedance Tomography Techniques for Detection of Decay Inside Trees
Autorzy:
Kieu, Duy Thong
Vu, Hong Duong
Nguyen, Thi Thu Hang
Nguyen, Thu Thuy
Powiązania:
https://bibliotekanauki.pl/articles/2020936.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
electrical impedance tomography
tree investigation
resistivity
conductivity
impedancja
przewodnictwo
opór elektryczny
Opis:
Trees play a critical role in creating green spaces in public areas such as streets, parks, schools, offices. Over time, the trees often get pests and diseases, and then rotten trees can break. To care for and conserve the trees, it is necessary to determine the condition inside the trunk, especially the possibility of having a hollow or not. Wood decay, modifications of moisture and ion content, density due to biotic and abiotic stress agents of water extremity, salinity, and infection strongly change (di-) electrical properties of wood. Hence, we propose to use electrical impedance tomography to detect the change in electrical properties inside the trees that can link to wood decay. In electrical impedance tomography, an array of electrodes is attached around the tree trunk, and small alternating currents are injected via these electrodes, so the resulting voltages are measured. Processing the data, we can construct the spatial distribution of impedance (or resistivity) of the object. In this work, we will present the preliminary results of our group research. We will show theoretical forward modeling results, followed by laboratory experiments and real data application. The results illustrate that electrical impedance tomography can be useful to define several decay scenarios inside the trees.
Źródło:
Inżynieria Mineralna; 2021, 2; 31--40
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical prediction of propeller-hull interaction characteristics using RANS method
Autorzy:
Tu, Tran Ngoc
Luu, Do Duc
Ha, Nguyen Thi Hai
Quynh, Nguyen Thi Thu
Vu, Nguyen Minh
Powiązania:
https://bibliotekanauki.pl/articles/258472.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
propeller
interaction
hull
wake fraction
thrust deduction
relative rotative efficiency
RANS equations
Opis:
The paper presents the results of computational evaluation of the hull-propeller interaction coefficients, also referred to propulsive coefficients, based on the unsteady RANS flow model. To obtain the propulsive coefficients, the ship resistance, the open-water characteristics of the propeller, and the flow past the hull with working propeller were computed. For numerical evaluation of propeller open-water characteristics, the rotating reference frame approach was used, while for self-propulsion simulation, the rigid body motion method was applied. The rotating propeller was modelled with the sliding mesh technique. The dynamic sinkage and trim of the vessel were considered. The free surface effects were included by employing the volume of fluid method (VOF) for multi-phase flows. The self-propulsion point was obtained by performing two runs at constant speed with different revolutions. The well-known Japan Bulk Carrier (JBC) test cases were used to verify and validate the accuracy of the case studies. The solver used in the study was the commercial package Star-CCM+ from SIEMENS.
Źródło:
Polish Maritime Research; 2019, 2; 163-172
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of Nitramine Explosives in Aqueous Solution by UV-Mediated Advanced Oxidation Process in Near-Neutral Conditions
Autorzy:
Khue, Do Ngoc
Bach, Vu Quang
Binh, Nguyen Thanh
Minh, Do Binh
Nam, Pham Thi
Loi, Vu Duc
Nguyen, Hoa Thanh
Powiązania:
https://bibliotekanauki.pl/articles/1838360.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
hexogen
octogen
tetryl
UV
photo-Fenton
electrooxidation
near neutral
Opis:
Explosive compounds are hazardous to the environment, posing a serious risk to human and animal health and the ecosystem. The primary goal of research was to compare the efficiency of UV/H2O2, photo-Fenton, electro (EO)/ UV/H2O2 processes at near-neutral pH (pH=6) on the degradation of nitramine explosives (NAs), such as hexogen (RDX), octogen (HMX), and tetryl (TET), in an aqueous solution. The effect of operational conditions, likely pH of the solution, initial H2O2 concentration, initial Fe2+ concentration, and solution temperature, was observed. The removal kinetics fit with first-order kinetics and were in the order: photo-Fenton >EO/UV/ H2O2 > UV/ H2O2. The results showed higher rate constant values for TET, RDX and HMX removal by UV/ H2O2 (k = 0.07778, 0.03791 and 0.03786 min-1), EO/UV/ H2O2 (k = 0.16599, 0.1475 and 0.08674 min-1) and photo-Fenton (k = 0.18018, 0.1501 and 0.09336 min-1) processes. Furthermore, TET, RDX and HMX were mineralized at 59.7%, 45.1%, and 25.1 %, respectively, under optimum conditions after 60 min of the photo-Fenton process. From the economic perspective, photo-Fenton only requires 2.132–4.113 kWh m-3 to completely reduce NAs. Finally, acute toxicity towards Vibrio fischeri was defeated after usage of near-neutral photo-Fenton. Thus, photo-Fenton at circum-neutral is promising for low-cost, eco-friendly and efficient processes for treating nitramine explosives in aqueous solutions.
Źródło:
Journal of Ecological Engineering; 2021, 22, 6; 232-243
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cadmium Immobilization in the Rice – Paddy Soil with Biochar Additive
Autorzy:
Thi, Khac Vu
Lan, Phuong Dinh Thi
Hang, Nga Nguyen Thi
Thanh, Hoa Nguyen
Powiązania:
https://bibliotekanauki.pl/articles/2086382.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
Cd
cadmium
soil contamination
rice grain
cadmium accumulation
biochar
straw
Opis:
Cadmium (Cd) is toxic for humans, but its effects on the yield and quality of rice under contaminated irrigation conditions remain uncertain. In this study, paddy soils in the Red River Delta (Vietnam) were selected for experiments with the purpose of understanding the effects of Cd contaminated irrigation water on growth, yields, and grain Cd accumulation. In addition, biochar was produced from rice husk (BRH) and rice straw for preventing Cd infiltration into rice was also studied in this experiment. A field experiment was established with applicated BRH and straw into polluted paddy soil, as a result the Cd content in grains reduced significantly. The Cd contaminated soil was added to the BRH and rice straw (RS) with six ratios, including: (1) RS 2.5%, (2) BRH 2.5%, (3) RS-BRH: 1.25–1.25%, (4) RS 5.0%, (5) BRH 5.0%, (6) RS-BRH: 2.5–2.5%, (w:w). Besides, three content levels 0.01–0.05–0.5 mg/L of Cd in irrigation water were applied throughout crop season. The results showed that the Cd accumulation in rice was in the following order: roots > stems > seeds. With 3 contaminated irrigation levels which were applied, the Cd concentrations of 0.05 mg/L and 0.5 mg/L affected plant height and yield. However, the Cd content in grains under contaminated soil condition can be controlled from 82.47–83.94% by applying a BRH ratio from 2.5–5% (w:w).
Źródło:
Journal of Ecological Engineering; 2022, 23, 4; 85--95
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Removal of Nitramine Explosives in Aqueous Solution by UV-Mediated Advanced Oxidation Process in Near-Neutral Conditions
Autorzy:
Khue, Do Ngoc
Bach, Vu Quang
Binh, Nguyen Thanh
Minh, Do Binh
Nam, Pham Thi
Loi, Vu Duc
Nguyen, Hoa Thanh
Powiązania:
https://bibliotekanauki.pl/articles/1838333.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
hexogen
octogen
tetryl
UV
photo-Fenton
electrooxidation
near neutral
Opis:
Explosive compounds are hazardous to the environment, posing a serious risk to human and animal health and the ecosystem. The primary goal of research was to compare the efficiency of UV/H2O2, photo-Fenton, electro (EO)/ UV/H2O2 processes at near-neutral pH (pH=6) on the degradation of nitramine explosives (NAs), such as hexogen (RDX), octogen (HMX), and tetryl (TET), in an aqueous solution. The effect of operational conditions, likely pH of the solution, initial H2O2 concentration, initial Fe2+ concentration, and solution temperature, was observed. The removal kinetics fit with first-order kinetics and were in the order: photo-Fenton >EO/UV/ H2O2 > UV/ H2O2. The results showed higher rate constant values for TET, RDX and HMX removal by UV/ H2O2 (k = 0.07778, 0.03791 and 0.03786 min-1), EO/UV/ H2O2 (k = 0.16599, 0.1475 and 0.08674 min-1) and photo-Fenton (k = 0.18018, 0.1501 and 0.09336 min-1) processes. Furthermore, TET, RDX and HMX were mineralized at 59.7%, 45.1%, and 25.1 %, respectively, under optimum conditions after 60 min of the photo-Fenton process. From the economic perspective, photo-Fenton only requires 2.132–4.113 kWh m-3 to completely reduce NAs. Finally, acute toxicity towards Vibrio fischeri was defeated after usage of near-neutral photo-Fenton. Thus, photo-Fenton at circum-neutral is promising for low-cost, eco-friendly and efficient processes for treating nitramine explosives in aqueous solutions.
Źródło:
Journal of Ecological Engineering; 2021, 22, 6; 232-243
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
VISION ZERO – Tools for Safety, Health, and Well-being Management and the Application in the Vietnamese Coal Mining Industry
Autorzy:
Nguyen, Nga
Meesmann, Urlich
Truong, Ngoc-Linh
Trinh, Vu-Hoa
Powiązania:
https://bibliotekanauki.pl/articles/2020192.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
Vision Zero
safety and health
Vietnamese coal mining industry
bezpieczeństwo
zdrowie
Wietnam
przemysł górniczy
Opis:
The Vietnamese mining industry is one of the most dangerous industries in the country. Mining companies understand safety and health for sustainable development at the mining sector and the national level. Thus, they have been applying many measures to improve their safety and health management achievements. Besides technology measures, organizational and personal measures are priorities. At the international level, VISION ZERO is a global movement based on the belief that all accidents, diseases, and harm at work are preventable. VISION ZERO develops its Seven Golden Rules to guide leaders, managers, and workers to create a safe and healthy working environment for the well-being of employees. The paper focuses on VISION ZERO, its theoretical aspects, and the application process in the Vietnamese coal mining companies.
Źródło:
Inżynieria Mineralna; 2021, 2; 365--372
1640-4920
Pojawia się w:
Inżynieria Mineralna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study on loan repayment options for power plant construction: a case study of the Son La hydropower plant, Vietnam
Badanie możliwości spłaty kredytu na budowę elektrowni: studium przypadku elektrowni wodnej Son La w Wietnamie
Autorzy:
Tu, Le Tat
Phap, Vu Minh
Huong, Nguyen Thi Thu
Powiązania:
https://bibliotekanauki.pl/articles/27312536.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
economic effects
electric power system
hydropower plant
investment
NPV
IRR
efekt ekonomiczny
system elektroenergetyczny
elektrownia wodna
inwestycja
Opis:
Using loans is an effective solution for the investment and construction of energy works in general and power plants in particular, especially for developing countries. In economic and financial studies of the project investment preparation stage, the options of using capital and paying interest will be taken into account to minimize risks and increase the project’s ability to pay due debts. However, it is difficult to know which loan repayment option is the most beneficial for the project and when the risk is for the project in the context of debt repayment. The current economic and financial analysis of the project mainly focuses on determining the feasibility of the project through basic parameters, such as net present value (NPV), benefit – cost – ratio (B/C), internal rate of return (IRR), profitability index (PI) and payback period (PP). These parameters do not indicate the most difficult time to pay off the project’s loans. This paper analyzes two options for repayment of long-term loans in Vietnam using the case study of Son La hydropower plant to clarify the above difficult times and recommend a suitable repayment plan for the power project. The analytical method is used to actualize the cash flow of capital and interest during the construction and operation of the works. In Option 1, the debt is paid annually for interest and capital with a constant amount of money during the repayment period. In Option 2, the original dept without interest is paid with a constant amount of money during the repayment period, the interest (due to the remaining original capital) must be paid in the year when the interest is incurred. The study results show that the amount of the annual payment in option 1 is smaller than in Option 2 in the first four years (of ten years of debt repayment). Thus, capital and interest payment in Option 2 may be more detrimental than Option 1 in the first three years of debt repayment, and the amount of money from debt repayment is greater than the profit obtained from power generation. Thus, depending on the profit in the first years when the power plant comes into operation, the investor needs to decide on a reasonable way to repay the loan so that the project can self-finance.
Korzystanie z kredytów jest skutecznym rozwiązaniem dla inwestycji i budowy zakładów energetycznych w ogóle, a w szczególności elektrowni, zwłaszcza w krajach rozwijających się. W analizach ekonomiczno-finansowych etapu przygotowania inwestycji projektu uwzględnione zostaną możliwości wykorzystania kapitału i spłaty odsetek w celu zminimalizowania ryzyka i zwiększenia zdolności projektu do spłaty wymaganych długów. Trudno jednak stwierdzić, która opcja spłaty kredytu jest najkorzystniejsza dla projektu i kiedy występuje ryzyko dla projektu w kontekście spłaty zadłużenia. Bieżąca analiza ekonomiczno-finansowa projektu koncentruje się głównie na określeniu wykonalności projektu poprzez podstawowe parametry, takie jak wartość bieżąca netto (NPV), stosunek korzyści do kosztów (B/C), wewnętrzna stopa zwrotu (IRR), wskaźnik rentowności (PI) i okres zwrotu (PP). Parametry te nie wskazują na najtrudniejszy czas na spłatę kredytów projektu. W niniejszym artykule przeanalizowano dwie opcje spłaty kredytów długoterminowych w Wietnamie na przykładzie elektrowni wodnej Son La, uwzględniając obecne trudne warunki i zalecając odpowiedni plan spłaty dla projektu energetycznego. Metoda analityczna służy do aktualizacji przepływów pieniężnych kapitału i odsetek w trakcie budowy i eksploatacji obiektu. W Wariancie 1 dług jest spłacany corocznie na odsetki i kapitał stałą kwotą w okresie spłaty. W Wariancie 2 pierwotny dług bez odsetek spłacany jest stałą kwotą w okresie spłaty, odsetki (należne od pozostałego kapitału pierwotnego) muszą być zapłacone w roku, w którym naliczone zostały odsetki. Wyniki badań wskazują, że wysokość rocznej spłaty w Wariancie 1 jest mniejsza niż w Wariancie 2 w pierwszych czterech latach (z dziesięciu lat spłaty zadłużenia). Zatem spłata kapitału i odsetek w Wariancie 2 może być bardziej szkodliwa niż w Wariancie 1 w pierwszych trzech latach spłaty zadłużenia, a kwota pieniędzy ze spłaty zadłużenia jest większa niż zysk uzyskany z produkcji energii. Zatem w zależności od zysku w pierwszych latach od uruchomienia elektrowni, inwestor musi zdecydować, jak rozsądnie spłacić kredyt, aby projekt mógł się sam sfinansować.
Źródło:
Polityka Energetyczna; 2023, 26, 2; 121--140
1429-6675
Pojawia się w:
Polityka Energetyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of Criteria for High-Technology Rice and Corn Suitability Assessment – A Case Study in the An Giang province, Viet Nam
Autorzy:
Nguyen, Phan Chi
Vu, Pham Thanh
Minh, Vo Quang
Tri, Le Quang
Khuong, Nguyen Quoc
Powiązania:
https://bibliotekanauki.pl/articles/2202337.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
An Giang province
corn production
high-tech
multi-criteria
rice production
Opis:
This study identified the zones likely to apply high-tech rice and corn technology based on criteria from different expert groups. Based on the resulting limiting factor for ability suitable, structural and non-structural solutions have been proposed to improve the suitability of rice and corn with high-tech applications. It was the basic foundation to support strategic planners in agricultural development sustainability in the future. High technology application in agricultural production is an inevitable trend in today’s society. In Vietnam, high-tech agricultural production has developed for a long time in high-tech industrial park production. However, in agricultural production, applying high technology with mass production has yet to have any specific regulations on criteria for implementation in production. On that basis, the research aimed at determining the requirements for developing high-tech agriculture with mass production. Therefore, the predefined criteria for primary and secondary data were developed, which were used for the data collected from farmers, managers, and scientists. Thereby, a production hierarchy of adaptations for rice and corn was built based on consultation results with the farmers and scientists and published studies. The results also made three land adaptation zones apply high technology in mass production for these two crops. The areas suitable for producing rice and corn with high technology applications were marginally suitable, and not suitable prevailed. No region in the An Giang province has a strong potential for cultivating high-tech rice and corn. This result also established adaptive upgrading solutions for applying high technology in the future, which helped improve agricultural production efficiency.
Źródło:
Journal of Ecological Engineering; 2023, 24, 1; 239--247
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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