Hong Kong University Of Science And Technology Research Articles

IEEE Fellows – Class of 2023 [Society Briefs

Professor Yike Guo is the Provost of the Hong Kong University of Science and Technology (HKUST). He is concurrently a Chair Professor in the Department of Computer Science and Engineering.

A Time of Change

A Time of Change

Inorganic Chemistry in Hong Kong

AbstractInorganic chemistry research has developed impressively in Hong Kong, attaining worldwide recognition. This Guest Editorial introduces the research showcased in the Institute Feature “Universities in Hong Kong”, which is conducted in seven universities: City University of Hong Kong (CityU), The Chinese University of Hong Kong (CUHK), The Education University of Hong Kong (EdUHK), Hong Kong Baptist University (HKBU), The University of Hong Kong (HKU), The Hong Kong University of Science and Technology (HKUST), and The Hong Kong Polytechnic University (PolyU).

A juxtaposed review on adsorptive removal of PFAS by metal-organic frameworks (MOFs) with carbon-based materials, ion exchange resins, and polymer adsorbents

The removal of poly- and perfluoroalkyl substances (PFAS) from the aquatic environment is a universal concern due to the adverse effects of these substances on both the environment and public health. Different adsorbents, including carbon-based materials, ion exchange resins, biomaterials, and polymers, have been used for the removal of short-chain (C < 6) and long-chain (C > 7) PFAS from water with varying performance. Metal-organic frameworks (MOFs), as a new generation of adsorbents, have also been recently used to remove PFAS from water. MOFs provide unique properties such as significantly enhanced surface area, structural tunability, and improved selectivity compared to conventional adsorbents. However, due to various types of MOFs, their complex chemistry and morphology, different PFAS compounds, lack of standard adsorption test, and different testing conditions, there are inconclusive and contradictory findings in the literature. Therefore, this review aims to provide critical analysis of the performance of different types of MOFs in the removal of long-chain (C > 7), short-chain (C < 6), and ultra-short-chain (C < 3) PFAS and comprehensively study the efficiency of MOFs for PFAS removal in comparison with other adsorbents. In addition, the adsorption mechanisms and kinetics of PFAS components on different MOFs, including Materials of Institute Lavoisier (MIL), Universiteit of Oslo (UiO), Zeolitic imidazolate frameworks (ZIFs), Hong Kong University of Science and Technology (HKUST), and other hybrid types of MOF were discussed. The study also discussed the effect of environmental factors such as pH and ionic strength on the adsorption of PFAS on MOFs. In addition to the adsorption process, the reusability and regeneration of MOFs in the PFAS removal process are discussed. Finally, challenges and future outlooks of the utility of MOFs for PFAS removal were discussed to inspire future critical research efforts in removing PFAS.

The multi-functional rotor aerodynamic and aeroacoustic test platform at HKUST

This paper describes the multi-functional rotor noise and aerodynamics test platform at the Hong Kong University of Science and Technology (HKUST). To investigate the noise characteristics of propellers with aerodynamic flows, the test rig is installed in the 2.5×2 (m) low-speed and low-noise wind tunnel in the Aerodynamic and Acoustic Facility (AAF) at HKUST. The wind tunnel can facilitate flow from 0 to 40 m/s. The test rig is assembled in a turntable on the ceiling of the tunnel wall, which enables the testing range of pitch angle can vary from 0° (axial flow) to 90° (parallel flow), with an accuracy of 0.1°. The noise produced by the rotor is measured by a set of wall-mounted surface microphones. Semi-empirical calibration is conducted to quantify the noise reflection by the tunnel walls. A low-noise struct has been designed and manufactured to locate a set of far-field microphones equipped with nosecone, to improve the quality of acoustic measurement inside the flow. In addition, a synchronized system is developed to conduct the phase-locking Particle Image Velocimetry (PIV) measurement on the rotor, to study the flow pattern to better understand the noise generation mechanism.

A flow and acoustic facility for characterization of liner and meta-acoustic surfaces under grazing flow condition

The Hong Kong University of Science and Technology (HKUST) has designed and assembled a new facility, a grazing flow tube, for aeroacoustic characteristics measurement of acoustic liners, e.g. transmission loss, impedance, etc., under a high-speed grazing flow. The cross-section of the test section of the tube has a dimension of 50 mm × 50 mm, and the grazing flow speed can be up to 0.3 Ma. A settling chamber, a long-enough flow development section and a multi-stage anechoic termination are adopted to ensure the high-quality flow field and acoustic field. This paper presents the detailed designs of the key components of the facility, as well as the calibrations of the velocity profile in a series of cross-section surfaces of the duct along the streamwise direction and sound pressure distributions in the axial and circumferential directions. Pitot tube, Hotwire and PIV are used to obtain the flow field measurement results. The overall performance of the diagnostic facility is verified by comparing the impedance results of acoustic liners acquired from an impedance tube under the static condition and the theoretical variation of axial wavenumber with Ma number under the grazing flow.

Experimental assessment of the noise characteristics of propellers for commercial drones

Multi-copters or drones are engaged in a wide range of industrial applications for their flexibility, safety and low-cost. The noise emission is becoming an issue with the expanding applications, among which the propellers that drive the drones are the major sources of noise. In this work, the noise characteristics of small-scale propellers is experimentally investigated using the advanced rotor aerodynamics and aeroacoustics test platform in an anechoic chamber at the Hong Kong University of Science and Technology (HKUST). The study will focus on the representative off-the-shelf propellers. The rotor noise will be measured by a linear array with 20 microphones, and the aerodynamic forces will be acquired by using the high-accuracy load cells. The dependence of both the tonal and broadband noise radiation with the thrust and rotation speed at various conditions will be tested. The study will enhance our understanding of the noise features of the multi-rotor powered drones, and will provide us with a better understanding of the status of the drone noise impact on the environment.

Design and characterization of a multifunctional low-speed anechoic wind tunnel at HKUST

The Hong Kong University of Science and Technology (HKUST) has installed and commissioned an Ultra-quiet Noise Injection Test and Evaluation Device (UNITED). This facility is the first closed-circuit anechoic wind tunnel in Hong Kong. Calibrations and improvements have been made to improve the aerodynamic and aeroacoustic performance since its commissioning in 2016, and various experiments have been conducted in it. The test section is enclosed within a 3.2 m × 3.1 m × 2 m anechoic chamber, and it can be configured as either open-jet or closed test section. The exit plane of the contraction section has a dimension of 0.4 m × 0.4 m, and the flow speed of the test section can be varied from 10 m/s up to 70 m/s. In this paper, the major design constraints and design principles of key wind tunnel sections are described. To achieve low background noise, a silencer network is carefully designed, and a low-noise axial fan is specially designed and manufactured for the wind tunnel circuit. It is shown that the metrics of aerodynamic and aeroacoustic performances are comparable to similar facilities across the world. Representative research activities are also briefly summarized in this paper. Particularly, the measurement of trailing edge noise of a flat plate is demonstrated. The measured trailing edge noise collapses well under the classical fifth power-law scaling, suggesting the good performance of the entire measurement system.

Accurate photovoltaic measurement of organic cells for indoor applications

Yong Cui received his PhD in polymer chemistry and physics from University of Chinese Academy of Sciences in 2019. He then worked as a postdoctoral researcher at Institute of Chemistry, Chinese Academy of Sciences (ICCAS). His research interests include the study of materials and device engineering toward high-performance organic photovoltaic cells for indoor applications. Ling Hong has been a PhD student at University of Chinese Academy of Sciences since 2016. She received her BS in chemistry from Lanzhou University in 2016. Her research focuses on eco-compatible solvent-processed organic photovoltaic cells. Tao Zhang received her MS in materials chemical engineering from Anhui University of Science and Technology in 2020. Currently, she is a research assistant in ICCAS. Her research interest focuses on investigation and development of high-performance organic photovoltaic cells. Haifeng Meng received her PhD in physical chemistry from the National Center for Nanoscience and Technology in 2010. She then worked in National Institute of Metrology, China. Her research interests focus on photodetector- and photovoltaic-related metrology. He Yan is a professor at Hong Kong University of Science and Technology (HKUST). Prof Yan got his BS from Peking University in 2000, followed by a PhD from Northwestern University in 2004. His group focuses on the design and synthesis, device fabrication, and characterization of organic semiconductors that can be applied in organic solar cells, organic transistors, and detectors. Feng Gao is a professor and Wallenberg Academy Fellow at Linköping University in Sweden. He received his PhD from the University of Cambridge (UK) in 2011, followed by a Marie Skłodowska-Curie postdoc fellowship at Linköping University. His group currently focuses on research into solution-processed energy materials and devices, mainly based on organic semiconductors and metal halide perovskites. Jianhui Hou has been a professor at ICCAS since 2010 and an adjunct professor at USTB since 2012. He received his PhD in physical chemistry from ICCAS in 2006. Then he worked as a postdoctoral researcher in University of California, Los Angeles (UCLA) from 2006 to 2008 and then Director of Research of Solarmer Energy, Inc. from 2008 to 2010. His group focuses on the design, synthesis, and application of photoelectric materials.

Henry Tye: the future of theoretical physics and advice to young researchers.

Professor Henry Tye (戴自海) is a world-renowned expert in theoretical particle physics, string theory and cosmology. He was recently the IAS Professor at the Jockey Club Institute for Advanced Study (IAS) and the Hong Kong University of Science and Technology (HKUST), and is the Horace White Professor of Physics (Emeritus) at Cornell University. He has a lot of experience in research status in both China and the United States. Recently, NSR invited Professor Yi-Fu Cai (蔡一夫) from the University of Science and Technology of China (USTC) to interview Prof. Tye on his personal views on the future of theoretical physics, his own experience, and his advice to young researchers.

Reaction: Engineer Biology for Uranium

Fei Sun is currently an associate professor at the Department of Chemical and Biological Engineering of the Hong Kong University of Science and Technology (HKUST). He obtained his BS and PhD degrees from Peking University and the University of Chicago, respectively. Before joining HKUST, he worked as a postdoctoral researcher at the California Institute of Technology. His primary research interests include protein engineering, synthetic biology, and biomaterials. Chuan He is currently the John T. Wilson Distinguished Service Professor in the Department of Chemistry at the University of Chicago. His research interests include topics in chemical biology, bioinorganic chemistry, and protein engineering.

Porous Membranes with Special Wettabilities: Designed Fabrication and Emerging Application

Porous materials have become a burgeoning research interest in materials science because of their intrinsic porous characteristics, versatile chemical compositions, and abundant functionalities. Re...

Experimental and numerical study of dynamic soil debris impact load on reinforced concrete debris-resisting barriers

In Hong Kong, design practice adopts the hydrodynamic load model to estimate the dynamic soil debris impact load on reinforced concrete debris-resisting barriers. A dynamic coefficient of 2.5 is empirically adopted, which takes into account the effect of the impact of boulders up to 0.5 m in diameter. With a view to rationalising the design of reinforced concrete debris-resisting barriers, the Geotechnical Engineering Office (GEO), in collaboration with the Hong Kong University of Science and Technology (HKUST), initiated a study to investigate the dynamic impact of soil debris. In particular, a series of large-scale impact tests using 4 m3 realistic debris mix and a 1.8-m-high reinforced concrete model barrier were conducted in the flume facility in the Kadoorie Centre in Hong Kong. The tests were well controlled, and the flow kinematics, including flow depth and flow speed, and the time history of the impact load at the wall stem subject to the debris impact were measured, which provided critical test data on assessment of the hydrodynamic load of soil debris hitting reinforced concrete structures. The scale of these physical impact tests under such a controlled environment was unique as compared with other studies in the literature. To further examine the dynamic impact force, a calibrated numerical model using a three-dimensional finite-element computer package, namely LS-DYNA, was adopted to simulate the impact scenario for a real-scale debris flow event of 400 m3, where an arbitrary Lagrangian-Eulerian technique was adopted to simulate debris materials. Based on both the experiments and numerical analyses, debris run-up along the wall stem was observed when the debris hit the model barriers. Under the experimental setting, the hydrodynamic soil debris pressure coefficients were consistently found close to unity, which are generally in line with that used in overseas technical guidelines or design practice. This study enhances fundamental understanding of the soil debris impact mechanism on reinforced concrete barriers and provides scientific evidence to rationalise the design guidelines used in Hong Kong.

HKUST’s Experience with CONSER: A Two Decade Partnership

The Library of the Hong Kong University of Science and Technology (HKUST), as the only CONSER full member outside North America, has entered into its twentieth year of CONSER membership. This article provides a historical overview of the Library’s participation in the program, its considerations and concerns when it first joined CONSER, and challenges and benefits it experienced over the years. The PCC-related activities that the Library has participated in have increased its growth in the field. The article concludes with future challenges the Library and its community will face.

Synthesis of Mesoporous MWCNT/HKUST-1 Composite for Wastewater Treatment

Metal–organic frameworks (MOFs) (Hong Kong University of Science and Technology (HKUST)-1) have been widely studied using the hydrothermal method. Recently, efforts have also been geared toward the incorporation of multiwalled carbon nanotubes (MWCNTs) into the HKUST-1 MOF to advance its applications for gas storage as well as pollutant removal in wastewater. However, a significant reduction in the MWCNT/HKUST-1 composite surface area has limited its applications. We therefore synthesized HKUST-1 and HKUST-1 impregnated with acid-treated multiwalled carbon nanotubes (FMWCNTs). A large surface area of 1131.2 m2g−1 was obtained after acid treatment of the as-received MWCNTs. HKUST-1 was found to have an average particle diameter of 6.5 to 8 µm with a BET surface area of 1176.66 m2g−1. The FMWCNT/HKUST-1 composites had a BET surface area of 1108.85 m2/g. The addition of FMWCNTs was found to increase the parent MOF pore volume from 0.76 to 1.93 cm3g−1. A BJH desorption cumulative pore size of 6.97 nm was obtained in a composite sample. The maximum adsorption capacity of the composites was found to be greater than 100 mg/g at 298 K. The results obtained indicate that FMWCNT/HKUST-1 nanocomposites are a potential adsorbent for methylene blue (MB) removal in dye synthetic water.

The people behind the papers - Mingxi Deng and Yan Yan.

Drosophila wing discs are epithelial sac-like organs and a powerful model for investigating the link between proliferation and patterning. Of particular interest is the question of how single cells in the disc integrate information regarding position and growth control, as morphogens that pattern an axis can also regulate cell division. A new Techniques and Resources article in Development reports the application of single cell sequencing technologies to dissociated discs in an effort to understand these problems. We caught up with first author Mingxi Deng and his supervisor Yan Yan, Assistant Professor at The Hong Kong University of Science and Technology (HKUST), to hear more about the story.

Real‐time dense mapping for online processing and navigation

AbstractAutonomous robots require accurate localizations and dense mappings for motion planning. We consider the navigation scenario where the dense representation of the robot surrounding must be immediately available, and require that the system is capable of an instantaneous map correction if a loop closure is detected by the localization module. To satisfy the real‐time processing requirement of online robotics applications, our presented system bounds the algorithmic complexity of the localization pipeline by restricting the number of variables to be optimized at each time instant. A dense map representation along with a local dense map reconstruction strategy is also proposed. Despite the limits that are imposed by the real‐time requirement and planning safety, the mapping quality of our method is comparable to other competitive methods. For implementations, we additionally introduce a few engineering considerations, such as the system architecture, the variable initialization, the memory management, the image processing, and so forth, to improve the system performance. Extensive experimental validations of our presented system are performed on the KITTI and NewCollege datasets, and through an online experiment around the Hong Kong University of Science and Technology (HKUST) university campus. We release our implementation as open‐source robot operating system (ROS) packages for the benefit of the community.

Preparation of iron‐based MIL‐101 functionalized polydopamine@Fe3O4 magnetic composites for extracting sulfonylurea herbicides from environmental water and vegetable samples

Here, we describe a simple one-pot solvothermal method for synthesizing MIL-101(Fe)@polydopamine@Fe3 O4 composites from polydopamine-modified Fe3 O4 particles. The composite was used as a magnetic adsorbent to rapidly extract sulfonylurea herbicides. The herbicides were then analyzed by high-performance liquid chromatography. The best possible extraction efficiencies were achieved by optimizing the most important extraction parameters, including desorption conditions, extraction time, adsorbent dose, salt concentration, and the pH of the solution. Good linearity was found (correlation coefficients>0.9991) over the herbicide concentration range 1-150μg/L using the optimal conditions. The limits of detection (the concentrations giving signal/noise ratios of 3) were low, at 0.12-0.34μg/L, and repeatability was good (the relative standard deviations were<4.8%, n=6). The method was used successfully to determine four sulfonylurea herbicides in environmental water and vegetable samples, giving satisfactory recoveries of 87.1-108.9%. The extraction efficiency achieved using MIL-101(Fe)@polydopamine@Fe3 O4 was compared with the extraction efficiencies achieved using other magnetic composites (polydopamine@Fe3 O4 , Hong Kong University of Science and Technology (HKUST)-1@polydopamine@Fe3 O4 , and MIL-100(Fe)@polydopamine@Fe3 O4 ). The results showed that the magnetic MIL-101(Fe)@polydopamine@Fe3 O4 composites have great potential for the extraction of trace sulfonylurea herbicides from various sample types.

A Case Study on the Success of HKUST Business School : With Focus on Full-time MBA Program

The Master of Business Administration (MBA) industry is bracing for growing crisis in Korea and around the globe. GMAC (2016) reported that 48% of 133 two-year MBA programs in 16 countries have experienced significant decline of applicants. This has been mainly caused by increasing financial burden, losing prestige of general MBA degrees, and challenges from online higher education including the Massive Open Online Course (MOOC). Amid the looming crisis of MBA, the Hong Kong University of Science and Technology (HKUST) Business School enjoyed an incredible year in 2016. The HKUST earned the 14th place in global MBA ranking, and the 1st position in Asia. In addition, the HKUST graduates have been ranked the world

Surface Functionalization of Metal–Organic Framework Crystals with Catechol Coatings for Enhanced Moisture Tolerance

Robust catechol coatings for enhanced moisture tolerance were produced in one step by direct reaction of Hong Kong University of Science and Technology (HKUST) with synthetic catechols. We ascribe the rapid formation of homogeneous coatings around the metal-organic framework particles to the biomimetic catalytic activity of Cu(II) dimers in the external surface of the crystals. Use of fluorinated catechols results in hydrophobic, permeable coatings that protect HKUST from water degradation while retaining close to 100% of its original sorption capacity.