TechTalk

HKAES TechTalk – Magneto-electric Dipole – Advanced Antenna Technology for a Smart World

Innovation Wing Two, TechTalk / By

Since Heinrich Hertz developed the first antenna in 1887 to demonstrate the existence of radio waves, the antenna has become the linchpin in countless wireless systems and devices. With the increasing demand for faster wireless connectivity, rising adoption of smartphones for consumer electronics, and accelerating digitization, stringent requirements, such as wide bandwidth and compact size, are imposed on antenna technology. The magneto-electric (ME) dipole is proposed to tackle the new challenges. It has been developed for mobile communications, global navigation receivers, radars, sensors, medical imaging systems and wireless power transfer systems. Compared with conventional antennas such as dipoles, slots and microstrip antennas, the ME dipoles have many distinguished features including wide bandwidth, low cross-polarization, low back radiation and stable gain and beamwidth over the operating frequencies. An overview of the theory and applications of the ME dipoles will be presented.

TechTalk – Environmental Geomechanics: Towards a Minimised Chemical Footprint in Geo-energy Engineering

Innovation Wing Two, TechTalk / By

November 23 2023 (Thursday) 4:30-5:30pm
Cracking is ubiquitous in a geomaterial when it is subject to an environmental perturbation. Controlling environmentally assisted subcritical crack growth is the key enabler to a safe and active geo-energy adaptation to Climate Change, particularly in the domain of e.g., unconventional shale hydrocarbon recovery, Carbon Capture Utilisation and Storage (CCUS) and enhanced geothermal systems (EGS). The aim of these applications is commonly to achieve an enhanced permeability and injectivity in the formation by the stimulation of hydraulic fracturing. In order to maximize the effectiveness of the technique and meanwhile limit the extent of chemical footprint, a sophisticated understanding of the feedback between the mechanics of a geomaterial and the surrounding environment it is subject to is required. In this talk, modelling approaches on the effect of chemical environment on subcritical cracking in a stressed geomaterial at multiple scales and an extension to an alternative non-destructive shear stimulation will be presented.

TechTalk – Live “Street View” of Intracellular Organelles’ Interactions

Innovation Wing Two, TechTalk / By

November 13 2023 (Monday) 3:00-4:00pm
The number of colors in fluorescence microscopy is far less than the types of intracellular compartments. I will present our recent progress in super resolution imaging and deep convolutional neuronal networks to segment 15 subcellular structures. This approach bypasses the limitations of multi-color imaging, accelerates the imaging speed by one order of magnitude, and can accurately segment vesicle organelles with similar shapes and sizes. The super-resolution advantages were demonstrated in resolving the 3D anatomic nanostructures at different mitotic phases and tracking the fast dynamic interactions among nine intracellular compartments in live cell. We show transfer learning ability of our networks among different microscopes, different cell types, and even complexed system of living tissues.

TechTalk – Waste to Wealth: Sustainable Land Reclamation Technologies

Innovation Wing Two, TechTalk / By

November 16 2023 (Thursday) 3:00-4:00pm
Land reclamation is one of the most effective solutions to address the severe problem of land shortage. By 2023, the total reclaimed area in Hong Kong is nearly equivalent to the whole area of Hong Kong Island. In Lantau Tomorrow Vision, there will be over 1700 hectares of new reclaimed land in the next 20-30 years, in which, the shortage of fill material will be a great challenge. Dredged marine deposits as a major solid waste are a potential fill material after stabilization. Chemically, waste ashes from industry were recycled, activated, and mixed with marine deposits to serve as fill material. The other biological method is also used, in which bacteria are adapted to induce calcium carbonate in marine deposits. The environmental impact and performance of the methods are evaluated. Without using cement, these green technologies could reduce carbon emissions, contributing to carbon neutrality, and promoting green and sustainable reclamation.

HKAES TechTalk – Fluid Mechanics for Carbon Reduction in Wastewater Treatment Plants –

Innovation Wing Two, TechTalk / By

November 2 2023 (Thursday) 4-5pm
The Hong Kong Harbour Area Treatment Scheme (HATS) serves a population of over 5 million. It ensures protection of the Tsuen Wan beaches and good water quality in Victoria Harbour. In the Stonecutters Island treatment works, 300 tonnes of 10 percent sodium hypochlorite solution (6 L/s) are dosed into a river of sewage (1.8 million m3/d) every day. In actual operation it is found that most of the chlorine is actually consumed without being used for disinfection. This talk presents an engineering innovation on how to mix the small chlorine dose with the large sewage flow, resulting in up to 30 percent reduction of chlorine demand – with significant savings of chemicals and reduction of carbon footprint of 1170 tonnes/year. The technology is generally applicable to chlorine disinfection of primary effluent in many developing countries.

Young Scholar TechTalk – GRAINS: Proximity Sensing of Objects in Granular Materials

Innovation Wing Two, TechTalk / By

October 17, 2023 (Tuesday) 4:30-5:30pm
Proximity sensing is a method of detecting the presence of objects without making physical contact. However, this concept has not been widely explored in the context of granular materials, which are materials composed of small particles like sand or gravel. This is because granular materials have complex properties and the sensing needs to work without the aid of vision. In this presentation, I will introduce a system called GRAINS (Granular Material-Embedded Autonomous Proximity Sensing). GRAINS is designed to sense objects buried within granular materials by utilizing fundamental principles related to the behavior of granules, such as how they flow like a fluid, how they can become jammed. GRAINS uses force signals to determine the proximity of buried objects. It achieves this by analyzing force anomalies that occur when granules become jammed due to their proximity to objects. These force anomalies are learned in real-time by the system using a mathematical technique called Gaussian process regression. To capture these patterns, a probe is moved along a spiral trajectory within the granular material. The results of our experiments demonstrate that GRAINS can adaptively adjust its parameters to effectively work with different types of granules. It can perceive objects in the nearby vicinity, approximately 0.5 to 7 cm ahead, without the need for direct contact with the buried obstacles.
(project page: https://sites.google.com/view/grains2/home)

TechTalk – Subsurface Technologies to Support the Energy Transition

Innovation Wing Two, TechTalk / By

October 12 2023 (Thursday) 3-4pm
To avoid catastrophic consequences of climate change, our current carbon-emitting energy infrastructure needs to be replaced with an energy system free from atmospheric carbon emissions. The enormous scale of this energy transition requires multiple energy sources to be developed, including carbon-free wind, solar, geothermal, and nuclear as well as fossil-fuel-based systems where the carbon dioxide from the waste stream is captured and stored securely in deep subsurface geologic formations, in a technology known as Carbon Capture and Storage, or CCS. Subsurface geologic formations are also likely to be used to provide short-term storage for energy-carrying fluids like hydrogen and natural gas, making the subsurface environment critical to the energy transition. In this talk, I will discuss practical computational approaches to analyze geological storage systems as well as economic and political issues associated with CCS. I will also briefly discuss basic climate change facts, as part of a proposed general curriculum for Environmental Literacy.