Wyniki wyszukiwania - BazTech

1

A study on time schedules for construction projects in Hanoi, Vietnam

Hai Dinh Tuan

Archives of Civil Engineering

|

2024

|

Vol. 70, nr 1

667--691

EN

With its position as the capital, Hanoi is the political center as well as the second largest economic center of the country. Therefore, the city is always allocated a large budget in construction investment to create material facilities for political tasks and economic and social development. During the implementation of construction projects, a number of difficulties and limitations have appeared. In which, projects are delayed in construction and disbursement, reducing investment efficiency and not meeting the expectations of the government and people. From this fact, the authors have conducted a study to evaluate the causes affecting the time schedule of construction projects in Hanoi. The method F-APH (Fuzzy Analytic Hierarchy Process) was used to analyze data objectively and accurately about the causes affecting the time schedule. From there, these causes are classified into groups of subjective causes (from within the project) and groups of objective causes (from outside the project). The results show that subjective causes, originating from project participants, have a stronger influence than objective causes. A number of specific proposals to the actors involved in construction projects are made to eliminate or limit the impact of the causes of construction progress.

2

Status and prospects of fully mechanized mining technology in Vietnam coal mines from 2005 to 2020

Duc Hai Duong, Hong Quang Dao, Van Viet Phan, Van Thang Ngo

Journal of Sustainable Mining

|

2023

|

Vol. 22. iss. 2

147--154

EN

This paper analyzes the achievement and the failures of applying the mechanized mining method in underground coal mines by the Vietnam National Coal e Mineral Industries Holding Corporation Ltd. (VINACOMIN) for 15 years (from 2005 to 2020). It also proposes the recommendations for developing mechanized mining in order to improve coal production, productivity and safety management for the sustainable development of Vietnam's underground coal mining in the period 2021-2025.

3

Radon-Radium Thermal Mineral Water in Vo Am Ecotourism Project Area, Ngoc Luong Commune, Yen Thuy District, Hoa Binh Province, Vietnam

Ban To Xuan, Dung Le Tien, Duc Tran Van, Trong Nguyen Huu, Tuan Truong Duc

Inżynieria Mineralna

|

2023

|

no. 2, vol. 1

327--333

EN

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.

4

Geological and Geochemical Characteristics of the Pac Lang Gold Deposits, Northeastern Vietnam and Their Potential Prospects

Khuong The Hung, Nguyen Van Dat, Nguyen Thi Cuc, Pham Nhu Sang

Inżynieria Mineralna

|

2023

|

no. 2, vol. 1

311--318

EN

The Song Hien Rift basin, located in northeast Vietnam, has been identified as an important region for gold deposits, including the Pac Lang deposit. Several methods like petrographic observations, elemental analyses, and geochemical elements and vertical zoning models of primary halo have been used to describe geological characteristic of this deposit. The investigation focused on examining the geological events that occurred both before and after the formation of the ore. The use of ICP-MS analysis and element concentration contrast enabled an effective assessment of the relative degrees of denudation that occurred at the Pac Lang deposit. The findings of this study were consistent with prior research on ore deposit geology, geochemical primary-halo, and examination of geochemical indicator zoning patterns for gold ore bodies. The study's application of singularity analysis for evaluating the degree of denudation provides important geological information that can aid in data interpretation. The results of the study can also have significant reference value in furthering our understanding of the post-ore deformation of deposits and in the investigation of unknown orebodies in northeast Vietnam. There indicate that, the research's findings suggest that the use of singularity analysis to evaluate the degree of denudation is a valuable tool for exploring potential gold deposits and enhancing our knowledge of gold deposit geology in northeast Vietnam. Overall, this study contributes to the existing body of knowledge on gold deposits in the Song Hien Rift basin and can serve as a useful reference for future research in the area.

5

Developing Criteria for Assessing The Stability of Water Supply Models in High Mountains and Water-Scare Areas

Nguyen Manh Truong, Dinh Anh Tuan, Nguyen Tiep Tan, Vu Thi Hong Nghia, Do Van Binh

Inżynieria Mineralna

|

2023

|

no. 2, vol. 1

179--186

EN

The article presents the scientific basis for assessing the stability of water supply models and develops a suitable set of criteria to assess the stability of water supply works, which includes the water supply part for water supply works and systems (including headworks and water distribution systems) in high mountains and water-scarce areas in Vietnam. Research results indicate that in order to improve the stability and availability of water of the models that have been, are and will be built, it is necessary to have a common method of evaluating effectiveness for scientific models of domestic water supply. Accordingly, it is necessary to build obtain a suitable set of criteria to assess the stability of the water supply model (source + water supply works) in the high mountains, water-scarce areas in Vietnam.

6

Temporal and spatial heterogeneity of the Ailaoshan–Song Ma–Song Chay ophiolitic mélange, and its significance on the evolution of Paleo-Tethys

Lin Wei, Liu Fei, Wang Ying, Meng Lingtong, Faure Michel, Chu Yang, Nguyen Vuong Van, Wu Qinying, We Wei, Thu Hoai Luong Thi, Vu Tich Van

Geotourism / Geoturystyka

|

2023

|

nr 1-2 (72-73)

42--43

EN

The ophiolite is the direct evidence to restore the oceanic evolution, and it is used to identify the convergence boundary of the plates. Compared with ophiolite, ophiolitic mélange, especially its matrix, contains more information about the evolution of ocean. The evolution of eastern Paleo-Tethys, between the South China and Indochina blocks, recorded the whole process of rifting from Gondwana and their northward migration and convergence. To understand the tectonic implications from matrix of ophiolitic mélange, the Mesozoic Paleo-Tethys Ailaoshan–Song Ma–Song Chay suture zone located in the North Vietnam–Southeast Yunnan region acts as an ideal study area. Based on the structural geology, we reviewed previous zircon U-Pb dating and Lu-Hf isotopic analyses on the detrital zircon from the Ailaoshan–Song Ma–Song Chay ophiolitic mélange. Accordingly, we subdivide the matrix of these ophiolitic mélange into four parts (M1, M2, M3, and M4; Fig. 1). M1 is mainly located in the middle segment of the Ailaoshan–Song Ma belt. It shows age peaks of 440 Ma and 960 Ma with εHf(t) values of −19.6 ~ +10.3. M2 is mainly located in the NW segment of the Ailaoshan–Song Ma belt, showing a dominant age peak of ~260 Ma. Particularly, it has εHf(t) values of −28.9 ~ +8.1. M3 is mainly located in the SE segment of the Ailaoshan–Song Ma belt, showing the peaks at ~250 Ma, 440 Ma, and 960 Ma with εHf(t) values of −21.9 ~ +10.1. M4 is mainly located in the Song Chay belt, showing the peaks at ~310 Ma, 470 Ma, 610 Ma, 770 Ma, and 965 Ma with εHf(t) values of −28.2 ~ +10.8. The geochronological data of the detrital zircon from the matrix of the Ailaoshan– Song Ma–Song Chay ophiolitic mélange zone, documents a temporal heterogeneity between the M1, M2, M3, and M4 units, which formed at 310–270 Ma, 265–250 Ma, 245–240 Ma, and 310–255 Ma, respectively. The different components and provenances of each unit reflect a strike-parallel heterogeneity (Fig. 1). The M1 unit was mainly sourced from the Paleozoic sedimentary rocks of the Indochina Block (IB). The main provenance for the M2 unit is Emeishan Large Igneous Province (ELIP). The magmatic arc developed in the IB provided the materials for the M3 unit, and the detrital materials of the M4 were mainly sourced from the South China Block (SCB) (Fig. 1). The Cenozoic strike-slip deformation led to an inverted geometry of the M1, M2, and M3 units, accounting for a strike-perpendicular heterogeneity straight to the strike of the orogenic belt. The temporal, strike-parallel, and strike-perpendicular heterogeneity help us to decipher the tempo-spatial evolution of the Paleo-Tethys. The M1, M2, M3, and M4 units contain information from different evolutionary stages, likely recording the comprehensive history of the ancient oceanic basin. Importantly, our results demonstrate that both the active continental margin of the IB and the passive continental margin of the SCB acted as provenance sources that supplied significant amount of detrital material in the ophiolitic mélange matrix, indicating that the Paleo-Tethys Ocean was a “narrow” or “limited” ocean rather than the archipelagic ocean proposed before.

7

Decoupling Analysis, Economic Structure on Environmental Pressure in Vietnam During 2008–2018

Huong Ta Thi

Ecological Engineering & Environmental Technology

|

2023

|

Vol. 24, iss. 9

191--203

EN

In this research, we display the trajectories of Vietnam’s environmental pressure throughout the years during 2008–2018 and identify the underlying socioeconomic driving factors through input-output and forward-backward linkage analysis. Decoupling index (DI) and input-output analysis (IOA) indicated that mining, the extraction, and use of fossil fuels, as well as energy generation for daily life and manufacturing industries, are the primary contributors to rising environmental pressures (DI; forward and backward linkage values > 1). Vietnam’s decoupling performance has four distinct phases. Mineral and fossil fuel depletion; climate change in the short-term and long-term, and water stress indexes (the ratio of total annual freshwater withdrawal to hydrological availability) were high with 456.91%; 55.91%; 54.43%; 41.87%; and 30%, respectively during 2008–2018.

8

Finite element model updating of steel-concrete composite bridge: A study case of the Ruri bridge in Vietnam

Nguyen Duc Cong, Salamak Marek, Katunin Andrzej, Gerges Michael, Abdel-Maguid Mohamed

Archives of Civil Engineering

|

2023

|

Vol. 69, nr 3

425--443

EN

The study presents the finite element (FE) model update of the existing simple-spans steel-concrete composite bridge structure using a particle swarm optimisation (PSO) and genetic algorithm (GA) approaches. The Wireless Structural Testing System (STS-WiFi) of Bridge Diagnostic, Inc. from the USA, implemented various types of sensors including: LVDT displacement sensors, intelligent strain transducers, and accelerometers that the static and dynamic historical behaviors of the bridge structure have been recorded in the field testing. One part of all field data sets has been used to calibrate the cross-sectional stiffness properties of steel girders and material of steel beams and concrete deck in the structural members including 16 master and slave variables, and that the PSO and GA optimisation methods in the MATLAB software have been developed with the new innovative tools to interface with the analytical results of the FE model in the ANSYS APDL software automatically. The vibration analysis from the dynamic responses of the structure have been conducted to extract four natural frequencies from experimental data that have been compared with the numerical natural frequencies in the FE model of the bridge through the minimum objective function of percent error to be less than 10%. In order to identify the experimental mode shapes of the structure more accurately and reliably, the discrete-time state-space model using the subspace method (N4SID) and fast Fourier transform (FFT) in MATLAB software have been applied to determine the experimental natural frequencies in which were compared with the computed natural frequencies. The main goal of the innovative approach is to determine the representative FE model of the actual bridge in which it is applied to various truck load configurations according to bridge design codes and standards. The improved methods in this document have been successfully applied to the Vietnamese steel-concrete composite bridge in which the load rating factors (RF) of the AASHTO design standards have been calculated to predict load limits, so the final updated FE model of the existing bridge is well rated with all RF values greater than 1.0. The presented approaches show great performance and the potential to implement them in industrial conditions.

9

Delay factors in the construction of irrigation and hydropower projects in Vietnam

Nguyen Van Son, Nguyen Huu Hue, Nguyen Duc Anh, Hai Dinh Tuan

Archives of Civil Engineering

|

2023

|

Vol. 69, nr 1

5--20

EN

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.

10

BIM competency in personnel recruitment in Vietnam construction enterprises

Anh Pham Xuan, Toan Nguyen Quoc, Nam Tran Phuong, Long Hoang Duy, Thang Do Duc

Archives of Civil Engineering

|

2023

|

Vol. 69, nr 2

381--397

EN

The world has been implementing Building Information Modelling (BIM) successfully to construction projects from small to large scale. In Vietnam and many other countries, BIM is also widely applied in different fields of the construction industry. However, there are still many problems that need to be solved. One of those is to determine the necessary BIM competencies, thereby develop BIM personnel recruitment standards. The article identifies the competencies as well as evaluates their importance when supporting the recruitment of BIM personnel in construction enterprises in Vietnam. Through survey forms such as survey on online recruitment, expert interviews, and survey forms, the study is conducted with Likert scale, relative importance index (RII) for result analysis and ranking the importance of BIM competency for three distinct group of positions in Vietnam. With this result, the authors hope that the study will be an important reference, contributing to the development and concretization of the required competency criteria in the recruitment of BIM personnel in Vietnam and other similar countries.

11

Assessment of factors influencing on the success of public-private partnerships infrastructure projects in Vietnam

Toan Nguyen Quoc, Hai Dinh Tuan

Archives of Civil Engineering

|

2023

|

Vol. 69, nr 1

343--365

EN

The implementation of public-private partnerships has become one of the effective models of cooperation between the public and private sectors in the development of infrastructure in Vietnam. This model has been adopted in Vietnam for many years and is intended to help governments build infrastructure and provide an opportunity to reduce government debt profiles. This study aims to identify the most critical factors that could determine the success of these projects. A questionnaire was conducted based on the participants’ experience in the implementation of public-private partnerships projects and a total of 216 respondents were received. A regression analysis shows that six critical success factors, including factors relevant to public sector, factors relevant to private sector, factors relevant to selected process partnerships, factors relevant to risk management systems, factors relevant to project information, and factors relevant to natural environment. The findings indicated that the most effective development projects could be carried out via PPPs if the government could focus on these important factors in the implementation process. The results will influence political development towards PPP and guide partners in developing public-private partnerships projects.

12

Raw Water Quality Assessment for Improvement Plan at Thu Duc Water Treatment Plant, Vietnam

Ho Ngo Anh Dao, Nguyen Thi Minh Trang, Nguyen Thi Trang Trung Nghia, Ngo Minh Khoi

Inżynieria Mineralna

|

2022

|

no. 2

135--140

EN

A conventional water treatment process is currently operated at Thu Duc Water Treatment Plant (TDWTP, Ho Chi Minh City, Vietnam) in which raw water is collected from Dong Nai River at Hoa An water intake and pumping station. The raw water quality is currently fluctuated due to the effects of run-off flows which has been increasing recently. This issue directly affects the operation and performance of existing treatment process at TDWTP since the current treatment are all based on traditional technologies and have been operating for a long time. This study is conducted to evaluate the quality of raw water collected at Hoa An intake station during the period of 2018–2020 with the aim to support the consideration of improvement and enhance the operation efficiency at TDWTP. The raw water quality is evaluated by investigating physico-chemical and biological parameters during the 36 months monitoring. This helps to produce a feasible and reliable results which may then can be used as a scientific database for the improvement plan at TDWTP. Results show that the changes of water quality during the investigated time is so complicated, and the concentration of most monitoring parameters is highly seasonal fluctuated. Specifically, the amounts of organic matters, microorganism, nitrogen compounds (NH4 +, NO2 - , NO3 - ) tend to increase strongly, which may be due to the urbanization and industrialization. The management of run-off flows on upstream of water intake and pumping station is also an important aspect which need to be considered to prevent the diffusion and spread of pollution. In addition, the effects of climate changes are the important reason which leads to the seasonal changes of flow and water quality. These issues cause a big challenge for TDWTP to maintain the treatment efficiency and overall performance. This study also proposes several management and technical solutions to address the changes of raw water quality in the future, which may be useful for TDWTP during their consideration to improve the treatment process.

PL

Konwencjonalny proces uzdatniania wody jest obecnie prowadzony w zakładzie uzdatniania wody Thu Duc (TDWTP, miasto Ho Chi Minh, Wietnam), w którym surowa woda jest pobierana z rzeki Dong Nai i z przepompowni Hoa An. Jakość wody surowej podlega obecnie wahaniom ze względu na skutki spływów, które ostatnio nasilają się. Kwestia ta ma bezpośredni wpływ na funkcjonowanie i wydajność istniejących procesów oczyszczania w TDWTP, gdyż wszystkie obecne działające oczyszczalnie oparte są na tradycyjnych technologiach i działają od dłuższego czasu. Niniejsze badanie ma na celu ocenę jakości wody surowej pobieranej ze stacji poboru Hoa An w latach 2018–2020 w celu wsparcia rozważań nad poprawą i zwiększeniem efektywności działania TDWTP. Jakość wody surowej oceniana jest poprzez badanie parametrów fizykochemicznych i biologicznych podczas 36-miesięcznego monitoringu. Pozwoliłó to uzyskanie wiarygodnych wyników, które następnie mogą być wykorzystane jako naukowa baza danych dla planu modernizacji TDWTP. Wyniki pokazują, że zmiany jakości wody w badanym okresie są bardzo złożone, a stężenia większości parametrów monitoringu podlegają dużym wahaniom sezonowym. Szczególnie silnie wzrastają ilości materii organicznej, mikroorganizmów, związków azotu (NH4 +, NO2 - , NO3 - ), co może być spowodowane urbanizacją i uprzemysłowieniem. Ważnym aspektem, który należy wziąć pod uwagę, aby zapobiec rozprzestrzenianiu się zanieczyszczeń, jest również zarządzanie przepływami odpływowymi przed ujęciem wody i przepompownią. Ponadto skutki zmian klimatu są ważną przyczyną sezonowych zmian przepływu i jakości wody. Kwestie te stanowią duże wyzwanie dla TDWTP, aby utrzymać skuteczność oczyszczania i ogólną wydajność. W niniejszym opracowaniu zaproponowano również kilka rozwiązań w zakresie zarządzania i rozwiązań technicznych mających na celu zajęcie się zmianami jakości wody surowej w przyszłości, które mogą być przydatne dla TDWTP podczas rozważań nad poprawą procesu oczyszczania.

13

Marine Plastic Litter in Phu Quoc Marine Protected Area, Vietnam: Current Status and Mitigation Approaches

Nguyen Thi Trang, Nguyen Tan Phong

Inżynieria Mineralna

|

2022

|

no. 2

107--113

EN

Marine plastic pollution causes adverse effects on global environment and marine ecosystems, particularly in marine protected areas. However, little is known of the effects of marine plastic debris on marine ecosystem services, human wellbeing, society, and the economy. We selected Phu Quoc Marine Protected Area (Phu Quoc MPA) for gaining an insight into current marine plastic debris as a first step towards understanding its effects on the environment and biodiversity in the region. This study applied secondary data analysis, semi-structured interviews, field measurements, and the quadrate line transect method in pursuit of the objective of the study. The findings reveal that marine plastic debris disposed of in Phu Quoc MPA dominantly came from diverse sources including rivers, streams, canals, tourism service providers, and marine aquaculture development areas. The abundance of macroplastic on the beaches was approximately between 1.109 and 0.248 items/m2 (equivalent to 0.082 ± 0.021 kg/m2). Most of the macroplastic were single-use plastics and accounted for more than 82%. The average size was approximately 14.932 ± 1.846 cm for items less than 30 cm. The remaining ones were HDPE plastic bags and plastic debris. The macroplastic and microplastic need to be stopped in order to encourage sustainable management of waste in the region.

PL

Zanieczyszczenie morza tworzywami sztucznymi powoduje niekorzystne skutki dla globalnego środowiska i ekosystemów morskich, szczególnie w morskich obszarach chronionych. Jednak niewiele wiadomo na temat wpływu plastikowych odpadów morskich na funkcjonowanie ekosystemów morskich, dobrostan ludzi, społeczeństwo i gospodarkę. Wybraliśmy Morski Obszar Chroniony Phu Quoc (Phu Quoc MPA), aby uzyskać wgląd w aktualne morskie odpady plastikowe jako pierwszy krok w kierunku zrozumienia ich wpływu na środowisko i różnorodność biologiczną w regionie. W badaniu tym zastosowano analizę danych wtórnych, częściowo ustrukturyzowane wywiady, pomiary terenowe i metodę transektu linii kwadratowej w dążeniu określenie wpływu czynników. Badania wykazują, że morskie odpady plastikowe usuwane w Phu Quoc MPA pochodziły z różnych źródeł, w tym z rzek, strumieni, kanałów, dostawców usług turystycznych i obszarów rozwoju akwakultury morskiej. Obfitość makroplastiku na plażach wynosiła w przybliżeniu od 1,109 do 0,248 sztuk/m2 (co odpowiada 0,082 ± 0,021 kg/m2). Większość makroplastiku to tworzywa sztuczne jednorazowego użytku, które stanowiły ponad 82%. Średni rozmiar wynosił około 14,932 ± 1,846 cm dla przedmiotów mniejszych niż 30 cm. Pozostałe to torby foliowe HDPE i odpady z tworzyw sztucznych. Należy powstrzymać wyrzucanie makroplastiku i mikroplastiku, aby zachęcić do zrównoważonego gospodarowania odpadami w regionie.

14

Rare earth elements in the Sin Quyen IOCG deposit, North Vietnam

Nguyen Dinh Chau, Pieczonka Jadwiga, Piestrzyński Adam, Khanh Phon Le, Duong Van Hao

Gospodarka Surowcami Mineralnymi

|

2022

|

T. 38, z. 1

17--60

EN

The Sin Quyen deposit is characterized by a high accumulation of rare earth elements (REE). This deposit belongs to the IOCG type copper deposits (Iron Oxide Copper-Gold Deposits). In the deposit, the REE carrier minerals have been identified as follow: allanite, titanite, uraninite, monazite, apatite, chevkinite, aeschynite, bastnäsite, and epidote. In the skarn zone, contents of allanite range from single percentages to 10% in hand-size specimens. Locally, minerals of epidote subgroup which occur in large amounts in the host rocks are important. The studied allanites have concentrations of: REE (14–27 wt%), Ca (9–16 wt%), Al (8–19 wt%), Si (26–34 wt%) and Fe (12–21 wt%). Two populations of allanite are documented, the first is texturally older and probably related to the Ca-K alteration (second stage of crystallization). This population has higher REE concentration ranging from 20 to 27 wt%. The second population is texturally younger and has a lower total REE concentration ranging from 14 to 19.9 wt%, which occur mostly as a rim surrounding the older and likely arose during the K alteration with Cu-Au mineralization (third crystallization). The chemical composition indicates that the studied allanites belong to the Ce-La-ferriallanite family, with low ΣHREE and an average of 0.21 wt.%. A temperature of 355°C which was calculated using a value of δ34S isotopes is interpreted as a temperature of the second crystallization stage of allanite. In the studied deposit, excluding allanite and titanite, the other bearing REE minerals have an insignificant role in the REE balance, since they either have the total content of REE, which is often close to the WDS detection limit (rf. the epidote subgroup), or their only occur at the single points. The content of total REE in accessory uraninites is high and range from 1.311% up to 7.959% with an average value of 4.852%.

XX

Złoże Sin Quyen charakteryzuje się wysoką zawartością pierwiastków ziem rzadkich (REE). Złoże to należy do typu złóż miedzi IOCG (Iron Oxide Copper-Gold Deposits). Zidentyfikowane minerały zawierające REE to: allanit, tytanit, uraninit, monacyt, apatyt, czewkinit, aeschynit, bastnäsyt i epidotyt. W próbkach wielkości dłoni, pobranych ze strefy skarnowej, zawartości allanitu wahają się od pojedynczych do 10%. Lokalnie, minerały podrzędnej grupy epidotytu są ważne z powodu ich licznego występowania. Badane allanity zawierają: REE (14–27 wt%), Ca (9–16% wag.), Al (8–19% wag.), Si (26–34% wag.) i Fe (12–21% wag.). Udokumentowano dwie populacje allanitu, pierwsza jest teksturalnie starsza i prawdopodobnie związana z alteracją Ca-K (drugi etap krystalizacji). Ta populacja ma wyższe koncentracje REE, które są zawarte w przedziale od 20 do 27% wag. Druga populacja jest młodsza i zawiera mniejsze ilości ziem rzadkich (od 14 do 19,9% wag.). Populacja ta występuje głównie w postaci obwódek regeneracyjnych, tworząc zrosty ze starszą populacją i jest związana z alteracją potasową oraz mineralizacją Cu-Au (trzeci etap krystalizacji). Skład chemiczny wskazuje, że badane allanity należą do podgrupy Ce-La-ferriallanitu, o niskiej i średniej koncentracji ΣHREE 0,21% wag. Temperatura krystalizacji 355°C, została obliczona na podstawie wartości δ34S. Ta temperatura jest interpretowana jako temperatura drugiego etapu krystalizacji. W badanym złożu, poza allanitami i tytanitami, inne minerały REE i ich nośniki mają małe znaczenie w bilansie ich zawartości. Na przykład sumaryczna zawartość REE w podrzędnie występującym epidocie, jest na poziomie wykrywalności metody WDS, a inne minerały, takie jak uraninit, czewkinit, aeschynit, czy bastnäsyt występują zbyt rzadko, aby wpływać na bilans tych metali. W akcesorycznym uraninicie, pomierzone zawartości REE wahają się w granicach 1,31–7,96%, przy średniej zawartości 4,85%.

15

Utilization of Geographic Information System (GIS) for urban management of RachGia City, Vietnam

Hai Dinh Tuan, Phin Trinh Thi

Archives of Civil Engineering

|

2022

|

Vol. 68, nr 2

521--530

EN

KienGiang province of Vietnam is the west coast of Mekong Delta, Vietnam where RachGia city is the provincial capital. In recent years due to impacts of climate change and extreme weather, the city’s urban infrastructure has been affected by saline intrusion, flooding, collapsed house, etc. Modeling remote sensing is useful to determine rainfall. Climatic factors are affected by temperature, wind, rain, drought that people feel comfortable or not comfortable in the area because the planning and management are not well. The application of Geographic Information System (GIS) technology has supported the method such as analysis, overlap the urban infrastructure and climate change impacts layers to produce the assessment that will support urban management. The objectives of this study is to assess the impact of climate change on some of RachGia’s infrastructures through the analysis of a number of thematic maps created from GIS Database. The database will be used by local agencies in urban management and development which take into account the climate change.

16

How do contractors select material suppliers for construction projects? Evidence from Vietnam

Toan Nguyen Quoc, My Hanh Nguyen Thi, Tam Nguyen Van, Anh Pham Xuan, Hai Dinh Tuan, Thuy Nguyen Thi

Archives of Civil Engineering

|

2022

|

Vol. 68, nr 3

273--288

EN

Materials play an important role in determining the quality and cost of a building, especially in the context of Vietnam’s rapid urbanization today. This study aims to analyze the status quo for supplier selection for construction projects in a developing country, Vietnam. Questionnaires are designed to conduct a survey among several contractors to assess the current situation of how Vietnamese construction enterprises select their material suppliers. Senior managers, project managers, site commanders, site engineers, foreman, office staff of contractors were interviewed. Based on result analysis of 117 valid responses, the most important criteria to consider when selecting material suppliers have been identified, with the most influential ones being price, delivery time, and material quality. However, the supply of materials still reveals some constraints that must be overcome. Vietnamese construction firms should pay more attention to supplier selection to optimize material delivery efficiency. This research contributes to the understanding of the status quo for supplier selection for construction projects in a developing country. This means contractors can adopt suitable measures to select material suppliers for construction projects.

17

Towards an insight into the adoption of open innovation by SMEs in Vietnam

Do Phuong Thanh, Le Ha Anh, Pham Nguyen Ngan Ha, Tran Le Chau, Le Tien Dat, Tran Thi Bich Hanh

Annals of Computer Science and Information Systems

|

2022

|

Vol. 34

99--105

EN

This study aims to identify the influential factors of OI adoption by SMEs in Vietnam, in order to provide useful theoretical and practical recommendations for SMEs to adopt OI effectively. Based on a survey of 56 Vietnamese SMEs, this study identified two drivers including improving capability and expanding network orientation, and four main barriers, including knowledge, collaboration, organisation, and financial strategy. Notably, the study found that collaboration barriers and network expansion orientation are factors that vastly impact the adoption of OI.

18

The impact of paradoxical leadership on public sector innovation through entrepreneurial orientation and goal congruence

Nguyen Tam, Matsoukas George, Lien Ha, Tran Que

Annals of Computer Science and Information Systems

|

2022

|

Vol. 34

165--174

EN

While leadership and entrepreneurship are recognized as essential factors in influencing innovation, the extent to which the constructs are interconnected and dependent on the public sector contextual environment is less well understood. In response, this study examined how public managers' paradoxical leadership and entrepreneurial orientation interact with public employees' perceptions of innovation at different levels of their goal congruence. Informed by the theory of ambidextrous leadership, we created a moderated mediation model of the influence of paradoxical leadership on public sector innovation via entrepreneurial orientation and goal congruence. Survey results were gathered from 339 subordinate-supervisor dyads in 69 teams from public sector departments in Ho Chi Minh City, Vietnam. SPSS was used to analyze the data using PROCESS-Macro. The results showed that the relationship between paradoxical leadership and public employees' innovation was totally mediated by the entrepreneurial orientation of public organizations. It was also found that paradoxical leadership fosters entrepreneurial orientation when there is a high level of goal congruence team members. However, paradoxical behavior of managers still increases entrepreneurial orientation in public organizations though goal congruence is at the low level. Thus, whether the goal congruence at a high or low rate, public managers appear to stimulate entrepreneurship correspondingly. Significantly, this study recommends a new theoretical model of paradoxical leadership as a feasible strategy to be implemented in the public sector, which may help public employees be innovative in unpredictable public-working situations. It is proposed that this research paradigm can be expanded to public organizations in cultural contexts comparable to Vietnam's.

19

Building a new “hospital governance” model based on the made in Vietnam lean management philosophy through the practice of the Covid-19 pandemic

Tien Thanh Nguyen, Dang Minh Nguyen, Thanh Thuy Nguyen Thi

Annals of Computer Science and Information Systems

|

2022

|

Vol. 34

221--226

EN

Research and propose a new model of ``Hospital governance'' based on The Made in Vietnam lean management philosophy a model is written based on recent research on practical activities in Vietnamese hospitals. The studied model has been effectively applied in some hospitals in Vietnam and provides the application process and some conditions for successful implementation. The model can be extended to domestic and international hospitals, including developed and developing countries.

20

Flood susceptibility mapping using advanced hybrid machine learning and CyGNSS: a case study of Nghe An province, Vietnam

Nguyen Huu Duy, Vu Phương Lan, Ha Minh Cuong, Dinh Thi Bao Hoa, Nguyen Thuy Hang, Hoang Tich Phuc, Doan Quang Cuong, Pham Van Manh, Dang Dinh Kha

Acta Geophysica

|

2022

|

Vol. 70, no 6

2785--2803

EN

Flooding is currently the most dangerous natural hazard. It can have heavy human and material impacts and, in recent years, flooding has tended to occur more frequently, due to changes our species has made to hydrological regimes, and due to climate change. It is of the utmost importance that new models are developed to predict and map food susceptibility with high accuracy, to support decision-makers and planners in designing more effective food management strategies. The objective of this study is the development of a new method based on state-of-the-art machine learning and remote sensing, namely random forest (RF), dingo optimization algorithm, a weighted chimp optimization algorithm (WChOA), and particle swarm optimization to build food susceptibility maps in the Nghe An province of Vietnam. The CyGNSS system was used to collect soil moisture data to integrate into the susceptibility model. A total of 1650 food locations and 14 conditioning factors were used to construct the model. These data were divided at a ratio of 60/20/20 to train, validate, and test the model, respectively. In addition, various statistical indices, namely root-mean-square error, receiver operation characteristic, mean absolute error, and the coefficient of determination (R2 ), were used to assess the performance of the model. The results for all the models were good, with an AUC value of+0.9. The RF-WChOA model performed best, with an AUC value of 0.99. The proposed models can predict and map food susceptibility with high accuracy.