EFFECT OF REDUCED CARBON SUPPLY ON ENHANCED BIOLOGICAL PHOSPHORUS REMOVAL AND DENITRIFICATION

Joint Research on Environmental Science and Technology for the Eart

Biomimetic Superhydrophobic Materials for Environmental Applications

Environmental pollution has been one of the people’s most significant concerns for decades. In today’s industrialized and modernized society, the problem of environmental pollution has become more and more serious, directly affecting the sustainable development of each country. The unique surface properties of materials and interfaces produced by biomimetic approaches can be leveraged to create practical solutions to challenging environmental issues. Among them, superhydrophobic materials get a lot of attention because of their exceptional capacities in various environmental applications such as oil-water separation, membrane-based water purification and desalination, biofouling prevention, high-performance vapor condensation, and atmospheric water capture. This chapter reviews and discusses the fundamental principles of superhydrophobicity, recent works in preparing superhydrophobic surfaces, their potential environmental applications, and the challenges confronted in their new applications

Defining student learning experience through blended learning

This paper aims to explore the benefits of Blended Learning towards students' learning experiences at an offshore campus of an Australian university located in Ho Chi Minh City, Vietnam. At the university campus, the Blended Learning practice in use is the displacement of content. Content displacement refers to a portion of the learning content and activities for a course being delivered online via the Learning Management System. Learning not only happens in face-to-face sessions at a given time but is extended to online spaces as well, happening anywhere at any time at students' preference. The focus of this research is its usefulness and effectiveness in promoting interactions between students and their peers, their teachers, and course materials. An online survey, which was designed based on a set of validated questions, was used to collect data from sixty-six students enrolled in eight Blended Learning courses. The analysis of the survey results provides empirical evidence to the claim that students' perception of their learning experiences at the university was beneficially impacted as a result of the Blended Learning environment in each of their classes. Specifically, factor analysis using oblique rotation method identifies a clear factor structure across survey questions, representing four dimensions of benefits: Engagement, Flexibility of learning, Online learning experience, and Self-confidence. In addition, significant differences between the clusters on these factors indicate that students vary in their responses towards the benefits of Blended Learning and their experience with a Blended Learning approach

Dynamic ACK skipping in TCP with Network Coding for Power Line Communication Networks

Transmission Control Protocol (TCP) still plays an essential role in various user applications for end-to-end reliable data transmission. However, TCP cannot get a high goodput performance in the lossy networks because it considers any packet loss to be a congestion signal and decreases the congestion window mistakenly. Therefore, TCP with Network Coding (termed TCP/NC) was proposed to recover the packet loss at the sink without retransmission if the number of coded packets is enough. However, the ACK packet needs to be sent for any arriving coded packet as a feedback of the end-to-end channel condition, resulting in a lower transmission performance in half- duplex networks, e.g., Power Line Communication. Therefore, we propose the ACK-Skipping scheme for TCP/NC to limit the number of ACK packets but still retain the necessary information, e.g., for channel estimation. The simulation result on ns-3 (Network Simulation 3) shows that the proposal achieves a higher goodput on PLC environment compared to TCP with Selective Acknowledgment and TCP Westwood+ as well as the recent variant of TCP/NC.The 22nd International Conference on Advanced Communications Technology, ICACT2020, 16-19 February 2020, Phoenix Park, PyeongChang, Kore

Photo-to-heat conversion of broadband metamaterial absorbers based on TiN nanoparticles under laser and solar illumination

We theoretically investigate photothermal heating of ultra-flexible metamaterials, which are obtained by randomly mixing TiN nanoparticles in polydimethylsiloxane (PDMS). Due to the plasmonic properties of TiN nanoparticles, incident light is perfectly absorbed in a broadband range (300-3000 nm) to generate heat within these metamaterials. Under irradiation of an 808 nm near-infrared laser with different intensities, our predicted temperature rises as a function of time agree well with recent experimental data. For a given laser intensity, the temperature rise varies non-monotonically with concentration of TiN nanoparticles because the enhancement of thermal conductivity and absorbed energy as adding plasmonic nanostructures leads to opposite effects on the heating process. When the model is extended to solar heating, photothermal behaviors are qualitatively similar but the temperature increase is less than 13 $K$. Our studies would provide good guidance for future experimental studies on the photo-to-heat conversion of broadband perfect absorbers.Comment: 8 pages, 7 figures, accepted for publications in Materials Today Communication

Dinophysis spp. recorded in the coastal waters of northern Vietnam during 2002-2003

A monitoring on toxins responsible for Diarrhetic Shellfish Poisoning (DSP) was carried out at several culture areas of hard clam (Meretrix meretrix) in the northern coast of Vietnam during May 2002 and December 2003. Quantitative observation of Dinophysis spp. was made one to four times every month and DSP toxins in the hard clam grown in the area was analyzed monthly using the HPLC method. Six species of Dinophysis were recorded, including D. caudata, D. fortii, D. miles, D. rotundata, D. mitra and D. hastata. Among them, D. caudata was the most common species. Others were not common and their densities were ignorable. D. caudata appeared almost all around the year at all sampling sites with density ranged from 0 to more than 3000 cells/l. However, it was more abundant during the warm period, i.e. from late February to late November. For the rest of a year, cells were rarely found. D. caudata was recorded in a wide range of temperature (15-34.3℃), but its significant density (over 100 cells/l) was only observed when water temperature exceeded 20℃. D. caudata appeared and could reach high density at all salinity in the range of 8-34 PSU. The highest recorded density was 3128 cells/l at 22℃ and 8.2 PSU in Thanh Hoa area in February 2003. ""Blooms"" of D. caudata, together with other dominant dinoflagellates, usually coincided with the vanishing period of diatoms. Okadaic acid (OA) was detected in edible part of clams but at low concentration in all samples. Maximal level was 80ng OA/100g, encountered in Thanh Hoa transect during August 2002 and April 2003. DTX 1-4 were not detected in all samples. No significant correlation between OA concentration in clam and the density of D. caudata in the water sample was observed, although toxins sometimes peaked the same time with D. caudata density. Low concentration of toxins implicates low risk of DSP and explains the absence of poisoning cases in the area so far. However, other shellfishes in the area should also be subjected to toxin monitoring

ADVANCED OXIDATION TREATMENT OF THE LEACHATE COLLECTED FROM WASTE DISPOSAL LANDFILL SITE IN HANOI, VIETNAM : APPLICATION AND ITS EFFECTS

Joint Research on Environmental Science and Technology for the Eart

A survey of multi-access edge computing in 5G and beyond : fundamentals, technology integration, and state-of-the-art

Driven by the emergence of new compute-intensive applications and the vision of the Internet of Things (IoT), it is foreseen that the emerging 5G network will face an unprecedented increase in traffic volume and computation demands. However, end users mostly have limited storage capacities and finite processing capabilities, thus how to run compute-intensive applications on resource-constrained users has recently become a natural concern. Mobile edge computing (MEC), a key technology in the emerging fifth generation (5G) network, can optimize mobile resources by hosting compute-intensive applications, process large data before sending to the cloud, provide the cloud-computing capabilities within the radio access network (RAN) in close proximity to mobile users, and offer context-aware services with the help of RAN information. Therefore, MEC enables a wide variety of applications, where the real-time response is strictly required, e.g., driverless vehicles, augmented reality, robotics, and immerse media. Indeed, the paradigm shift from 4G to 5G could become a reality with the advent of new technological concepts. The successful realization of MEC in the 5G network is still in its infancy and demands for constant efforts from both academic and industry communities. In this survey, we first provide a holistic overview of MEC technology and its potential use cases and applications. Then, we outline up-to-date researches on the integration of MEC with the new technologies that will be deployed in 5G and beyond. We also summarize testbeds and experimental evaluations, and open source activities, for edge computing. We further summarize lessons learned from state-of-the-art research works as well as discuss challenges and potential future directions for MEC research

Direct Observation of Exceptional Points in Photonic Crystal by Cross-Polarization Imaging in Momentum Space

This study explores exceptional points (EPs) in photonic crystals (PhCs) and introduces a novel method for their single-shot observation. Exceptional points are spectral singularities found in non-Hermitian systems, such as leaky PhC slabs. However, directly observing EPs in PhC systems using regular reflectivity spectroscopy is a considerable challenge due to interference between guided resonances and background signals. In this work, we present a simple, nondestructive technique that employs crossed polarizations to directly observe EPs in momentum-resolved resonant scattering. This approach effectively suppresses the background signal, enabling exclusive probing of the guided resonances where EPs manifest. Our results demonstrate the formation of EPs in both energy-momentum mapping and isofrequency imaging. All experimental findings align seamlessly with numerical simulations and analytical models. Our approach holds great potential as a robust tool for studying non-Hermitian physics in PhC platform