Causal Relationships among Management Factors Impacting on Construction Projects Success in Vietnam

Hai Pham,Soo-Yong Kim,Truong-Van Luu,Thai-Son Mai 대한토목학회 2017 대한토목학회 학술대회 Vol.2017 No.10

Fabrication and Characteristics of Fully-sprayed ZnO/CdS/CuInS2 Solar Cells

Tran Thanh Thai,Nguyen Duc Hieu,Luu Thi Lan Anh,Pham Phi Hung,Vo Thach Son,Vu Thi Bich 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.9

This paper reports the successful fabrication of deposited Glass/ZnO/CdS/CuInS₂ solar cells with superstrate structure using Full Spray Pyrolysis Deposition (FSPD). The structure, optical and electrical properties of the constituent layers are investigated. It is observed that the CuInS₂ (CIS) film deposited from starting solution with [Cu]/[In] = 1.1, and Al-doped CuInS₂ (CIAS) film deposited from solution with [Cu]/[In] = 1.0, [Al]/[In] = 0.12, and using sulfurization process exhibited the best crystallites with tetragonal structure. The optical band gap of the CIAS film is obtained as 1.49 eV. Some physical properties of both ZnO, and CdS thin films are also studied. The parameters of the cells obtained are V_OC = 425 mV, J_SC = 14.02 mA/cm², FF = 28.75% and efficiency of 1.71%. The results in our experiment show that FSPD is a potential technique to prepare solar cells based on CIS absorbers in a superstrate structure with low cost and high performance.

Understanding the COVID-19 Infodemic: Analyzing User-Generated Online Information During a COVID-19 Outbreak in Vietnam

Ha-Linh Quach,Thai Quang Pham,Ngoc-Anh Hoang,Dinh Cong Phung,Viet-Cuong Nguyen,Son Hong Le,Thanh Cong Le,Dang Hai Le,Anh Duc Dang,Duong Nhu Tran,Nghia Duy Ngu,Florian Vogt,Cong-Khanh Nguyen 대한의료정보학회 2022 Healthcare Informatics Research Vol.28 No.4

Objectives: Online misinformation has reached unprecedented levels during the coronavirus disease 2019 (COVID-19) pandemic. This study analyzed the magnitude and sentiment dynamics of misinformation and unverified information about public health interventions during a COVID-19 outbreak in Da Nang, Vietnam, between July and September 2020. Methods: We analyzed user-generated online information about five public health interventions during the Da Nang outbreak. We compared the volume, source, sentiment polarity, and engagements of online posts before, during, and after the outbreak using negative binomial and logistic regression, and assessed the content validity of the 500 most influential posts. Results: Most of the 54,528 online posts included were generated during the outbreak (n = 46,035; 84.42%) and by online newspapers (n = 32,034; 58.75%). Among the 500 most influential posts, 316 (63.20%) contained genuine information, 10 (2.00%) contained misinformation, 152 (30.40%) were non-factual opinions, and 22 (4.40%) contained unverifiable information. All misinformation posts were made during the outbreak, mostly on social media, and were predominantly negative. Higher levels of engagement were observed for information that was unverifiable (incidence relative risk [IRR] = 2.83; 95% confidence interval [CI], 1.33–0.62), posted during the outbreak (before: IRR = 0.15; 95% CI, 0.07–0.35; after: IRR = 0.46; 95% CI, 0.34-0.63), and with negative sentiment (IRR = 1.84; 95% CI, 1.23–2.75). Negatively toned posts were more likely to be misinformation (odds ratio [OR] = 9.59; 95% CI, 1.20–76.70) or unverified (OR = 5.03; 95% CI, 1.66–15.24). Conclusions: Misinformation and unverified information during the outbreak showed clustering, with social media being particularly affected. This indepth assessment demonstrates the value of analyzing online “infodemics” to inform public health responses.

Smart city as a social transition towards inclusive development through technology: a tale of four smart cities

Juhyun Lee,Julia Babcock,Thai Son Pham,Thu Hien Bui,Myounggu Kang 서울시립대학교 도시과학연구원 2023 도시과학국제저널 Vol.27 No.-

Smart city initiatives have the potential to address many contemporary urban challenges, utilizing information and technology. Increasingly, smart cities are considered as social innovation processes to achieve sustainable and inclusive urban development, being influenced by broader socio-economic and institutional contexts of cities. This paper explores ‘smart city transitions’ across varied urban contexts, in particular, how smart city transitions are enacted and how they contribute to inclusive urban transformation and public value. Using a multiple case studies approach, the research investigated infrastructure planning practices in Amsterdam in the Netherlands, Seoul in Korea, Portland in the U.S. and Ho Chi Minh City (HCMC) in Vietnam, cities that were known for strong efforts to establish integrated platforms to enhance societal benefits. Our analysis showed that each city has addressed its goals around sustainability, equity and affordability by reinforcing the engagement of multiple actors with the support of integrated platforms that facilitate open and multi-directional information flow in a transparent manner. In Amsterdam, innovative solutions for sustainable use of resources have been invented and distributed through multi-level social networks, contributing to the transformation into a circular economy. In Seoul and HCMC, the city's persistent efforts to utilize an open and integrated platform resulted in proactive engagement and collaboration of public and private actors in improving quality, equity and efficiency of transit services. Portland has tackled inequitable access and mistrust issues by setting principles for data governance and facilitating equity in the adoption of innovative technologies. Our research revealed that four cities established different forms of integrated platforms such as a centrally-controlled platform and a community-centred platform in order to address specific socio-economic issues within an institutional setting of each city. We concluded that building an integrated platform is not easy, but it is a critical prerequisite for the process of sustainable transformation to truly achieve smart cities across the globe.

The Influence of Hydrotalcite Intercalated with Benzoate on UV Stability of Acrylic Coating

Thuy Duong Nguyen,Anh Son Nguyen,Thu Thuy Thai,Gia Vu Pham,Thi Xuan Hang To,Marie-Georges Olivier 한국부식방식학회 2020 Corrosion Science and Technology Vol.19 No.1

It is important to realize that benzoate was intercalated into hydrotalcite (HTC-Bz) by the co-precipitationmethod. In this case, acrylic coating with 0.5 wt% HTC-Bz was deposited on carbon steel using the spincoating method. Next, the HTC-Bz structure was characterized by Field emission scanning electron microscopy(FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). In fact, an ultravioletvision spectroscopy (UV-Vis) was used to determine the benzoate content in HTC-Bz, and the UV absorptionability of HTC-Bz. Using electrochemical techniques, water contact angle measurement, and thermal-gravimetricanalysis, we compared the protective properties before and after QUV test, hydrophobicity and the thermalstability of acrylic coating containing HTC-Bz. The obtained results showed that HTC-Bz with a plate-likestructure was successfully synthesized; benzoate was intercalated into the interlayer of hydrotalcite witha concentration of 28 wt%. Additionally, it was noted that HTC-Bz has an UV absorption peak at 225nm. In conclusion, the addition of HTC-Bz enhanced the UV stability, hydrophobicity and the thermal stabilityof acrylic coating.

Effect of Zn/Al Cation Ratio on Corrosion Inhibition Capabilities of Hydrotalcites Containing Benzoate Against Carbon Steel

Thuy Duong Nguyen,To Thi Xuan Hang,Thu Thuy Pham,Anh Son Nguyen,Thu Thuy Thai,Gia Vu Pham,Ngoc Bach Ta 한국부식방식학회 2022 Corrosion Science and Technology Vol.21 No.6

Corrosion inhibitors based on Zn-Al hydrotalcites containing benzoate (ZnAlHB) with different molar ratios of Zn/Al were prepared with a co-precipitation process. Compositions and structures of the resulting hydrotalcites were studied with suitable spectroscopic methods such as inductively coupled plasma mass spectrometry (ICP-MS), ultraviolet-visible spectrophotometry (UV-Vis), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and surface zeta potential measurements, respectively. Results of physico-chemical studies showed that crystallite sizes, compositions of products, and surface electrical properties were significantly changed when the molar ratio of Zn/Al was increased. The release of benzoate from hydrotalcites also differed slightly among samples. Anticorrosion abilities of hydrotalcites intercalated with benzoate at a concentration of 3 g/L on carbon steel were analyzed using electrochemical impedance spectroscopy (EIS), polarization curve, energy-dispersive X-ray spectroscopy (EDX), and SEM. Corrosion inhibition abilities of benzoate modified hydrotalcites in 0.1 M NaCl showed an upward trend with increasing Zn/Al ratio. The reason for the dependence of corrosion resistance on the Zn/Al ratio was discussed, including changes in the microstructure of hydrotalcites such as crystal size, density, uniformity, and formation of ZnO.