Novel rapid indoor air quality and electricity usage monitoring system

As the COVID19 pandemic has caused people to spend more time indoors, it has become increasingly important to monitor indoor air quality. Dr Anthony Law, Adjunct Associate Professor of the Department of Mechanical Engineering, in collaboration of the Campus Sustainability Office and Department of Building Services Engineering of PolyU jointly developed a novel “Rapid indoor air quality and electricity usage monitoring system”. By installing sensors and releasing tracer gas at locations like wet markets and restaurants, the system can automatically track and analyse airborne transmission path of viruses. The system was piloted on campus in early 2020 and will be used in the community through collaboration with local green organisations. 理大最新研發空氣監測系統　助疫情下追蹤空氣病源 【橙新聞】 10 Sep 2020 理大研發新空氣質素監測系統　可推算室內病毒傳播範圍 【Now新聞台】 2 Sep 2020 理大研發新空氣監測系統 可推算室內新冠病毒傳播範圍 【頭條日報】 2 Sep 2020 理大研發室內空氣質素監測系統　可分析食肆換氣率及污染物走向 【香港01】 2 Sep 2020 理大研發空氣質素監測系統　可用於餐廳街市追蹤污染物 【明報】 2 Sep 2020

ME researchers and collaborators developed untethered soft robotics with staked graphene assembly

Developing untethered soft robots with programmable configurations is of great value yet a grand challenge in robotics. Recently, this challenge has been successfully attempted by a research team led by Dr Haimin Yao, Associate Professor from the Department of Mechanical Engineering of the Hong Kong Polytechnic University (PolyU), jointly with Dr Tao Chen, Professor from Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences. The research team started with the transferring of a layer of stacked graphene assembly (SGA) on a polyethylene (PE) substrate. The as-prepared SGA/PE bilayer exhibits curling behavior upon the variation of temperature (Fig. 1a, d). More interestingly, if an SGA/PE bilayer is pre-treated with a tempering process (heating followed by cooling) in a constrained space, it will coil spontaneously into a roll when it is freed (Fig. 1a-c). Surprisingly, the PE layer now is wrapped inside the SGA layer, which is opposite to that of the un-tempered sample. Such unusual morphing behavior of SGA/PE bilayer was found attributed to the asymmetric elastoplastic property of the SGA layer as demonstrated by the molecular dynamics simulations (Fig. 2a, b). It is the asymmetric elastoplastic property of SGA that allows them to prepare a variety of morphing systems with programmable initial morphologies (Fig. 3). These structures can be further assembled to construct more complicated actuation systems, such as artificial mimosa (Movie 1). More importantly, the tempered SGA/PE roll can achieve rolling locomotion under infrared lighting, resulting in an untethered light-driven motor (Movie 2). “Our work not only demonstrates an alternative strategy in creating untethered soft robots and reconfigurable devices but also provides a new philosophy for fabricating 2D material-based smart materials and structures,” said Dr Yao. This work has been recently published in Nature Communications [“Asymmetric elastoplasticity of stacked graphene assembly actualizes programmable untethered soft robotics”, https://www.nature.com/articles/s41467-020-18214-0]. Ms Yang Gao and Mr Anran Wei, two PolyU ME PhD graduates are the co-first authors and Dr Yao is one of the corresponding authors.

ME PhD Student won Young Professionals Grant for INTER-NOISE 2020

PolyU ME PhD student Muhammad Irsalan Arif won the prestigious Young Professionals Grant (YP Grant) for the 49th International Congress on Noise Control Engineering (INTER-NOISE 2020) to be held on 23-26 August 2020 in Seoul, Korea. The goal of the grant is to encourage students/young engineers to attend INTER-NOISE Congress and Mentoring Workshop. The Workshop provides mentorship on professional skills (networking, communication, job skills etc.) and allows Young Professional Awardees to hold informal discussions with world renowned experts in the field of acoustics. The INTER-NOISE Congresses are the largest international gathering of experts in noise control engineering held each year. The INTER-NOISE Congresses have been held annually since 1972 at venues around the world. The Congresses include a large technical program consisting of papers and posters on all topics of noise control engineering. The congresses also include an exhibition of the latest products and instrumentation for noise control engineering. INTER-NOISE provides the best opportunity for engineers and scientists in all fields of acoustics to learn about and share their work with peers from around the world. The YP Grant is highly competitive where the participants from all around the world submit their applications based on their research work. The applications are reviewed by an International Institute of Noise Control Engineering (I-INCE) judging panel and only few applications are selected for the grant. Muhammad Irsalan Arif applied regarding his research work on the development of a novel noise control methodology for airfoil tonal noise based on flow-induced vibration of an elastic panel. The methodology is superior to conventional approaches as it provides remarkable noise reduction yet does not sacrifice any airfoil aerodynamics. This feature is considered extremely beneficial for devising next generation aircraft wing noise control. The research idea has been highly rated by the judging panel and his application is selected for the YP Grant. Muhammad Irsalan Arif is currently working under the supervision of Dr Randolph Leung, Department of Mechanical Engineering, The Hong Kong Polytechnic University.

ME Professor appointed as VP of I-INCE

In the 49th International Congress on Noise Control Engineering (INTER-NOISE 2020) held on 23-26 August 2020, Prof. Li Cheng, Chair Professor of Mechanical Engineering, was appointed by the I-INCE board as the Vice-president Asia Pacific, for a three-year term till 2023. The I-INCE (International Institute of Noise Control Engineering) was founded in 1974. It is a worldwide consortium of organizations concerned with noise control, acoustics and vibration, with more than 50 member societies representing over 40 countries. As the VP, Prof. Cheng is responsible for overseeing and coordinating I-INCE activities in Asia Pacific region. Prior to this new appointment, he served as a Director in the I-INCE board for three years. Among other activities, I-INCE is the sponsor of the INTER-NOISE Series of International Congresses on Noise Control Engineering, which is the largest international gathering of experts in noise control engineering held each year since 1972. The 47th edition of the INTER-NOISE was held in Hong Kong, co-organized by the Hong Kong Polytechnic University and the Hong Kong Institute of Acoustics.

ME final year project selected by NVIDIA as the Project of the Month

Congratulations! A final year project conducted by our Mechanical Engineering (ME) students has been selected by NVIDIA as the Project of the Month in July 2020 in Jetson Community Projects. The group, consisting of three final year undergraduate students, XU Xinrui, YANG Chen, and ZHANG Yuming, supervised by Dr Henry CHU, worked on a project to design a self-navigating robot for search and rescue. They developed the robot based on a Jetson Nano platform and incorporated signals from LiDAR and camera to guide the robot to move autonomously in an unknown environment. They had also integrated a robot arm and vision-based algorithms to aid the robot for delivering materials from one location to another as specified on the map. This project is a very good example to show how the AI technology can be applied to the engineering field. Every month, the NVIDIA’s Jetson Team reviews the projects uploaded to their forum and selects the outstanding one for the award. Former winners include companies and top universities in US and Europe. Learn more: NVIDIA Jetson Community Projects

ME researchers co-authored a paper in Science again

Alloys that have high strengths at high temperatures are crucial for a variety of important industries including aerospace. Long-range ordered superlattice alloys with strong chemical binding and associated low atomic mobility are attractive for this purpose. However, most conventional ordered alloys with ultrahigh strengths (gigapascal levels) are found to be extremely brittle during tensile deformation, which severely limits their potential use in structural applications. A recent paper on a new class of high-strength and ductile superlattice alloys, co-authored by Mr Lei Fan, PhD student, and Dr Zengbao Jiao, Assistant Professor of the PolyU Department of Mechanical Engineering, was recently published in Science. In collaboration with Prof. CT Liu from the CityU and other colleagues, the researchers designed nanoscale disordered interfaces from the multi-element co-segregation, which act as a sustainable ductilizing source and prevent brittle intergranular fractures by enhancing dislocation mobilities. The newly developed multicomponent superlattice materials exhibit ultrahigh strengths of 1.6 gigapascals with tensile ductilities of 25% at ambient temperature. Moreover, these materials achieve negligible grain coarsening with exceptional softening resistance at elevated temperatures, demonstrating high thermal stability. These superlattice materials will be of great interest for a broad range of aerospace, automotive, nuclear power, chemical engineering, and other applications. In addition, the fundamental strategy of composite architecture can be utilized to design high-strength, ductile and stable materials in many other metallic systems. Read more at: T. Yang, Y.L. Zhao, W.P. Li, C.Y. Yu, J.H. Luan, D.Y. Lin, L. Fan, Z.B. Jiao, W.H. Liu, X.J. Liu, J.J. Kai, J.C. Huang, C.T. Liu. Ultrahigh-strength and ductile superlattice alloys with nanoscale disordered interfaces. Science, 2020; 369 (6502): 427.

Success in securing GRF 2020/21

In the 2020/2021 results of grants from the Research Grants Council’s General Research Fund (GRF) announced in June 2020, ME’s success rate for the GRF was 36% in 2020/21 exercise. Eight of our GRF proposals were funded. Congratulations to the following colleagues who were successful in securing a GRF grant in this round. Principal Investigator Project Title Prof. CHENG Li Enhanced Acoustic Black Hole Effects through Intentional Mechanical/Electromechanical Coupling and Nonlinearities Dr CHOY Yat Sze Acoustics behavior of orifice with shallow backing cavity under grazing flow for development of perforated panel type metamaterial for fan noise control Prof. FU Ming-wang Size effect affected anisotropy and asymmetry in multi-scaled deformation of metallic materials Dr LEUNG Chi Kin Randolph Passive Control of Cavity Aeroacoustic Resonance Using Localized Surface Compliance Prof. SU Zhongqing Non-invasive Ultrasound Monitoring of Blood Viscosity Using A Stretchable, Conformal, and Wearable Nanocomposite Sensing Array: Fundamental Research & Proof of Concept Prof. WEN Chihyung Richtmyer–Meshkov Instability in a Multilayer Cylinder Configuration Dr WONG Wai-on Design of a tunable hybrid vibration damper with Coulomb and electromagnetic shunt damping Dr ZHANG Peng Towards Quantitatively Predictive Modelling of Droplet Collision in Spray Simulation: Headon Collision of Equal-size Droplets

ME Staff Honoured for Loyal Service

Colleagues of the PolyU Department of Mechanical Engineering (ME) has always been devoting themselves to the development of ME. This year, the Department Head, on behalf of the University, paid tribute to long-serving staff members for their loyal and committed service over the years. Prof. TL Chan received the Long Service Award for his 30 years of service in PolyU. Ms Lily Tam, Leader of Administrative Staff, received the Award for 25 years. Mrs Michelle Lai, Clerical Officer II, for 35 years. Mr KK Tang, Technician, for 30 years. Congratulations to the awardees and heartfelt thanks for their years of dedication and devotion which have marked the achievements of the Department.

ME PHD student received Young Research Award in CNERC Annual Technical Symposium 2020

Bingchen Zhou, a PolyU ME PhD student, won the Young Research Award in the Chinese National Engineering Research Centre for Steel Construction (CNERC) Annual Technical Symposium 2020 held on 12 June 2020 at PolyU. She presented her research on “Effects of Cu on the nanostructure and mechanical properties of high strength steels” at the symposium. The CNERC Annual Technical Symposium 2020 is a technical symposium organized by the CNERC aiming at promoting technological development, sharing and exhibiting the findings and accomplishments among researchers of CNERC projects. Through applied engineering research on steel construction, the CNERC aims to capitalize on huge potentials offered by construction professionals in Hong Kong to further enhance socio-economic development through technological advancement in sustainable infrastructure development. The CNERC receives strong support from the Development Bureau of the Government of Hong Kong SAR and also from the Construction Industry Council. Bingchen Zhou is under the supervision of Dr Zengbao Jiao in the ME department. Her research interest focuses on the development and characterization of advanced high-strength steels strengthened by nanoscale co-precipitates.

Transferring nanofiber technology to develop highly protective facemasks for railroad operators

Avalon Nano-Biotech (HK) Limited has provided a donation to the ME department of 3 million Hong Kong dollars to support Prof. Wallace Leung in further developing and commercializing advanced air filtration nanofiber technologies to capture airborne pollutants and viruses (e.g., COVID-19 virus). Alongside with new technology development, Prof. Leung together with Avalon has transferred a nanofiber technology, which has been licensed earlier to Avalon, for the immediate need of developing a highly protective facemask for professionals working in railroad environment. This is especially vital during the current COVID-19 pandemic. A new clean room for class 8 under ISO 14644-1 has been built in MTR Siu Ho Wan Depot in 3 months to accommodate several facemask production lines that have incorporated nanofibers into the facemasks. The produced facemasks are provided to over 17,000 MTR employees in Hong Kong. Protecting the health of MTR employees is very important as they serve nearly 6 million Hong Kong passengers riding the rail daily. This is also the first clean room ever built by the railroad service provider in the world to produce facemasks for their employees. The technology adopted by MTR is based on the nanofiber filter technology developed by Prof. Leung’s R&D group in ME since 2006. The nanofiber facemask has been certified for the ASTM level II standard with PFE (particulate filtration efficiency) and BFE (bacterial filtration efficiency) both exceeding 98% by certifying agency. In fact, the PFE and BFE of the nanofiber facemask are above 99% in the certification testing. Further, the nanofiber facemask can also capture 20-60 nm nanoaerosols with filter efficiency of 95-98%. Also, the facemask can be used in dirty environment with high aerosol loading. Not only the facemasks offer high protection against tiny invisible aerosols and airborne viruses, the pressure drop for the facemasks are relatively low providing comfort to wearers. All these merits are extremely beneficial for railroad operators and professionals. Prof. Leung has also helped to set up quality assurance and quality control to ensure all the produced facemasks in the MTR Siu Ho Wan Depot clean room meet the stringent requirements per ASTM level II certification. This ensures the nanofiber technology is well transferred into a sound and useful product that benefit the Hong Kong community.