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- Quan-Hoang Vuong (27)
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The use of geopolymer concrete (GPC) in common load-bearing structures is still limited, mainly due to the lack of specific design procedures and limited understanding of the stress–strain behavior under uniaxial loading. The present work investigates the mechanical responses of GPC under axial compressive load by conducting a large number of experiments. For this purpose, 198 samples with three GPC mixes were designed, including concrete grades of 30, 40, and 50 MPa. The samples were prepared following the ASTM standards to determine the stress–strain relationship under compression. The results showed that fly ash-based GPC had average elastic modulus values of 30.424, 31.497, and 33.650 GPa, respectively, for G30, G40, and G50, lower than estimated using formulae for Ordinary Port... |
The turbine shaft is an important part of the turbocharger structure. This part requires quite high hardness, especially when operating it needs high strength to ensure the working conditions with very high speed, pressure and temperature. This paper presents the research results of the effects of temperature and heat retention time at high tempering on the hardness and tensile strength of the turbine shaft in the HX40W model turbocharger structure made of 42CrMo steel |
In our search for novel small molecules activating procaspase-3, we have designed and synthesized two series of novel (E)-N'-arylidene-2-(2-oxoindolin-1-yl)acetohydrazides (4) and (Z)-2-(5-substituted-2-oxoindolin-1-yl)-N'-(2-oxoindolin-3-ylidene)acetohydrazides (5). Cytotoxic evaluation revealed that the compounds showed notable cytotoxicity toward three human cancer cell lines: colon cancer SW620, prostate cancer PC-3, and lung cancer NCI-H23. Especially, six compounds, including 4f–h and 4n–p, exhibited cytotoxicity equal or superior to positive control PAC-1, the first procaspase-3 activating compound. The most potent compound 4o was three- to five-fold more cytotoxic than PAC-1 in three cancer cell lines tested. Analysis of compounds effects on cell cycle and apoptosis demonstr... |
We report on the magnetic properties of biphase iron oxide nanorods (NRs) consisting of ferrimagnetic Fe3O4 and antiferromagnetic α-Fe2O3 phases. Annealing as-prepared NRs at 250 °C for 5h, significantly improved the crystallinity of the Fe3O4 phase and enhanced the volume fraction of the α-Fe2O3 phase. Magnetometry data consistently reveal these two magnetically distinct phases, which are not in proximity to each other but separated by a region of disordered spins giving rise to enhanced magnetization at low temperatures when the sample was cooled down from 300 K in the presence of a 1T field to 10 K. This phenomenon which is also known as the pinning effect is much more pronounced in the annealed sample, resulting from the increased volume fraction of the α-Fe2O3 phase which could... |
The first Sustainable Development Goals (SDGs) of The United Nations aims to “end poverty in all its forms everywhere”. Its seven associated targets aim, among others, to eradicate extreme poverty for all people everywhere. In Vietnam, poverty eradication in ethnic minorities and mountainous areas are among the top priorities. This study aims to learn about farmers’ livelihoods associated with perceived difficulties in Chau Thai Commune, Nghe An Province, a rural mountainous area in Vietnam. A random sampling technique and a face-to-face interview method were employed to conduct a field survey in the region in 2018. The dataset collected from 215 households shows that Chau Thai Commune's livelihood largely depends on agriculture and forestry. Plantation forest and livestock are majo... |
We study a solution approach for a staffing problem in multi-skill call centers. The objective is to find a minimal-cost staffing solution while meeting a target level for the quality of service to customers. We consider a common situation in which the arrival rates are unobserved random variables for which preliminary forecasts are available in a first stage when making the initial staffing decision. In a second stage, more accurate forecasts are obtained and the staffing may have to be modified at a cost, to meet the constraints. This leads to a challenging two-stage stochastic optimization problem in which the quantities involved in the (nonlinear) constraints can only be estimated via simulation, so several independent simulations are required for each first-level scenario. We p... |
Quorum sensing is a well-known term for describing bacterial cell–cell communication. Bacteria use quorum sensing pathways to respond to external factors such as nutrient availability, defense mechanisms, and coordinate host toxic behaviors such as biofilm formation, virulence production, and other pathogenesis. Discovery of novel compounds which inhibit quorum sensing without being antibiotic are currently emerging fields. Herein, the library of fifteen benzo[d]thiazole/quinoline-2-thiol bearing 2-oxo-2-substituted-phenylethan-1-yl compounds was designed, synthesized and evaluated to find novel quorum sensing inhibitors. Firstly, compounds were evaluated for their growth inhibitory activities at high concentrations up to 1000 μg mL−1 toward Pseudomonas aeruginosa. Under our conditi... |
MgO is an abundant mineral in the rocky mantle of terrestrial planets, but its melting behaviors remain enigmatic. Here we introduce a simple theoretical model to investigate the B1-liquid transition of MgO up to 370 GPa. Vibrational free energies of B1-MgO are fully computed by the moment recurrence technique in quantum statistical physics. On that basis, we associate the melting temperature with the isothermal bulk modulus via the work-heat equivalence principle. This strategy allows us to quantitatively explain recent experimental data. Our numerical analyses would yield insights into planetary dynamics and evolution. |
Freshwater shortage and the growing demand for electricity are the most common issues on the path toward achieving global sustainability. Therefore, finding creative solutions involving the use of renewable energy sources presents the main challenge. Herein, we developed a cost-effective and highly efficient 2-in-1 integrated conical device consisting of multi-walled carbon nanotubes deposited filter paper, and iron wire, capable of simultaneously generating not only freshwater but also electricity from seawater. |
We execute the quantum eraser, the Elitzur–Vaidman bomb, and the Hardy’s paradox experiment using high-level programming language on a generic, gate-based superconducting quantum processor made publicly available by IBM. The quantum circuits for these experiments use a mixture of one-qubit and multi-qubit gates and require high entanglement gate accuracy. The results aligned with theoretical predictions of quantum mechanics to high confidence on circuits using up to 3 qubits. The power of quantum computers and high-level language as a platform for experimenting and studying quantum phenomena is henceforth demonstrated. |
