Science in Brief

Batteries from scrap metal
Chinese scientists have made good use of waste while finding an innovative solution to a technical problem by transforming rusty stainless steel mesh into electrodes with outstanding electrochemical properties that make them ideal for potassium-ion batteries.

As reported in the journal Angewandte Chemie, the rust is converted directly into a compact layer with a grid structure that can store potassium ions. A coating of reduced graphite oxide increases the conductivity and stability during charge/discharge cycles.

Lithium ion batteries are widely used in portable electronics, but lithium is expensive and reserves are limited.

Dr Zhang Xin-bo and a team from the Chinese Academy of Sciences and Jilin University have found a way to use rejected stainless steel mesh from filters and sieves to make novel electrodes. The corroded mesh is dipped into a solution of potassium ferrocyanide. This dissolves iron, chromium, and nickel ions out of the rust layer. They combine with ferricyanide ions into the complex salt known as Prussian blue, a dark blue pigment that is deposited onto the surface of the mesh as scaffold-like nanocubes. Potassium ions can easily and rapidly be stored in and released from these structures.

The researchers then use a dip-coating process to deposit a layer of graphene oxide, which nestles tightly onto the nanocubes. Subsequent reduction converts the graphene oxide to reduced graphene oxide, which consists of layers of graphite with isolated oxygen atoms that inhibit clumping and detachment of the active material while significantly increasing conductivity and opening ultrafast electron-transport pathways.

In tests, coin cells made with these new electrodes demonstrate excellent capacity, discharge voltages, rate capability and outstanding cycle stability. Because the inexpensive, binder-free electrodes are very flexible, they are highly suitable for use in flexible electronic devices.

Demo plant produces fuel from CO2 from air
A unique Soletair demo plant developed by VTT Technical Research Centre and Lappeenranta University of Technology (LUT) of Finland uses CO2 to produce renewable fuels and chemicals. The pilot plant is coupled to LUT's solar power plant in Lappeenranta.

The aim of the project is to demonstrate the technical performance of the overall process and produce 200 litres of fuels and other hydrocarbons for research purposes. This concerns a one-of-a-kind demo plant in which the entire process chain, from solar power generation to hydrocarbon production, is in the same place.

The demo plant comprises four separate units: a solar power plant; equipment for separating CO2 and water from the air; a section that uses electrolysis to produce hydrogen; and synthesis equipment for producing a crude-oil substitute from CO2 and hydrogen. Pilot-scale plant units have been designed for distributed, small-scale production. Production capacity can be increased by adding more units.

The pilot project will provide a platform for conducting research with international companies. Information gathered during the project will be useful for the commercialisation of the technologies.

Computer-guided strategy to accelerate materials discovery
Researchers at the University of Liverpool in the UK have developed a computer-guided strategy that led to the discovery of two new materials in the laboratory.

In a paper published in Nature, researchers describe an algorithm that uses chemical understanding of the structures of known materials to suggest which new combinations of atoms will create a new material that is stable and can be synthesised. The researchers were then able to create two new materials in the laboratory by experimental synthesis guided by the computer calculations.

Discovering new materials has been a slow and intensive process as there are millions of possible combinations of molecules and atoms. Exactly which combinations of elements will form materials is controlled by the structure that the material adopts (the arrangement of the atoms in space), which in turn depends on which elements are involved, and how many of each type. The challenge is to find those combinations that are stable and potentially synthesisable from the millions that are created.

Liverpool materials chemist, Prof Matt Rosseinsky, said: "Understanding which atoms will combine to form new materials from the vast space of possible candidates is one of the grand scientific challenges, and solving it will open up exciting scientific opportunities that could lead to important properties.

The HKIE Veneree Club
By Ir Dr CHAN Fuk Cheung

Celebrating the 5th anniversary of the club for retired engineers

Introduction
The HKIE Veneree Club was formed on 18 January 2012 in response to the President's initiatives for the Session 2011/2012, to facilitate sharing by retired engineers with young engineers and to promote social exchange among members. The HKIE Presidential Address by this writer, presented on 15 September 2011, had the following statement: "Retired engineers, irrespective of the type of engineering work they did, have a wealth of engineering experience that can be beneficial to young engineers. The HKIE should encourage such experience sharing. ..... To better care for our retired engineers, a club for them will be set up in the HKIE, called Veneree Club". Ir John T W Sze is the founding Chairman of the HKIE Veneree Club. Currently, the Veneree Club is managed under the leadership of Chairman Ir S W Cheung together with ten committee members.

'Veneree' is a French word with a meaning of 'venerated person'. The Club's Chinese name is "ͽǪ". The Club provides a channel for retired engineers to actively help engineering development and, at the same time, provides activities that retired engineers can enjoy. For example, monthly tea gatherings are organised along with light and interesting talks on a wide range of topics. Retired engineers are encouraged to offer professional enhancement lectures, mentor associate members and be school engineers for secondary schools. These were the initial ideas when the HKIE Veneree Club was first formed. According to the HKIE's record in 2012, there were around 500 retired engineers. In 2017, the number has increased to around 960. To fulfil its objectives, Veneree Club organises activities to enrich the knowledge and social connections of members and to nurture young engineers. Apart from monthly tea gatherings and talks, there are also visits and outings as well as provision of engineering advice to the community.

Enriching activities
In the morning of the third Wednesday of every month, Veneree Club organises a tea gathering and invites guest speakers to give presentation on various interesting topics ranging from health and life enjoyment to the environment and advances in engineering development, etc. The talk is usually held at the HKIE Headquarters, from 10:00am to noon. In this friendly environment, members meet both new and old friends as well as broaden their knowledge. The talks receive very good responses. The number of participants increased from an average of around 25 in 2012 to more than 60 in 2017.

From time to time, Veneree Club also organises outings for its members. These include hikes, boat trips and visits to Science Park, museums and the Legislative Council, etc. These social activities promote friendship among the members and help experience sharing. It is definitely a good demonstration of lifelong learning among our retired engineers.

The HKIE Engineering Exposition is a major annual event organised for our young engineers. When it was first held in May 2013, it was co-organised by Veneree Club and the HKIE Young Members Committee. The theme of the Exposition was "From Engineering Career to Life Challenges". Twelve experienced engineers from different disciplines were invited as guest speakers to share their experience in career development, the challenges they faced, and the attitude they adopted. Although their paths may be different and their specialties may vary, they all took very positive steps to accomplish their goals.

To allow speakers to elaborate their experience more deeply, in 2014 we invited only six speakers and re-focused the theme on "Engineering Life Challenges". In addition to presentations, there was a panel discussion to enable more interaction with the floor. Starting from 2015, Veneree Club took the sole responsibility of organising this annual event. There is a lunch gathering at the end of the Exposition too. At each table, an experienced engineer will sit among the young engineers to facilitate exchange of experience in a more casual manner. This arrangement has proved to be very successful. Each year, the event attracts about 200 young engineers from different disciplines and companies. Ir Philip Kwong was the organising committee chairman for these Engineering Exposition events.

HAD's AP Easy Scheme
In response to the invitation of the Home Affairs Department (HAD) in 2014, Verenee Club represented the HKIE in providing a voluntary service for the Government's AP Easy Scheme, which aimed to assist selected Owner's Corporation (OC) of eligible buildings aged 20 years and above. Under the leadership of Ir Dr Y L Choi, Veneree Club deployed six expert teams, each comprising two retired engineers, to meet with OCs and provide advice for cases referred by HAD. In order to help train young engineers in handling public affairs, we also recruited eight young engineers as assistants to observe the interviewing process and prepare notes of meetings. Representatives from Veneree Club also gave talks on building maintenance and advised on technical issues at seminars organised by HAD as a social service.

Club matters
The HKIE Veneree Committee is normally held in the early morning at the HKIE, the day before the tea gathering and talk. The Committee adopts a simple, leisurely and relaxed meeting style with harmony and enjoyment in mind. The minutes of meeting are in the form of mind-maps highlighting key issues being discussed and agreed. Thank you to our Hon Secretary Mr David Cheung for drawing these amazing minutes.

The operation of Veneree Club was first funded directly by the HKIE with an amount of HK$10,000 in both 2012 and 2013. Subsequent to the successful organisation of the Engineering Exposition with the financial support of sponsors, Veneree Club was able to contribute the surplus from the event towards the purchase of premises for the HKIE Headquarters amounting to HK$20,000 in March 2015 and HK$10,000 in December 2016 respectively. Thank you to our Hon Treasurer Ir Peter Tsang for his effective management of financial matters.

5th anniversary celebration
To celebrate the 5th anniversary of the Veneree Club, a 5 min video was prepared (YouTube link at: https://youtu.be/ITU3zsfiqIo). It highlights the activities organised over the past five years.

HKIE members interested in joining our Veneree activities are welcome to submit their contact details during one of the regular Wednesday meetings. Your name will then be placed in the email circulation list. Details of Veneree Club activities can be found on the HKIE website under 'Event of Interest Group' at http://www.hkie.org.hk/eng/html/EventsInterestGps/VenereeClub.asp.

Any HKIE member who has retired from the practice of his profession or business and is not in full-time employment may apply to the HKIE Council to pay a reduced annual subscription, dependent on the length of his continuous membership, as detailed below:

- Continuous membership of 25 years and over: 90% remission
- Continuous membership of at least 20 years but not more than 25 years: 60% remission
- Continuous membership of at least 15 years but not more than 20 years: 30% remission

Any member who has retired may continue to pay his full membership fees for a sufficient period to earn the reduction he or she desires.

Retired members are exempt from the mandatory Continuing Professional Development requirement.

Should you wish your membership status to be changed, please submit your declaration in the members� login area of the HKIE website at http://www.hkie.org.hk. Upon receipt of your declaration, your membership status will be changed to 'retired'. Should you require further assistance, please contact the Membership Section of the HKIE. If you have joined HKIE for more than 50 years, you will automatically receive a letter in the month when you reached 50 years of membership, showing that your membership fee will be waived from that year onward.

Acknowledgments
Veneree Club would like to express its gratitude to the HKIE Headquarters for its support. The present Chairman Ir S W Cheung would like to thank all past and present committee members for their hard work and good team spirit to make Veneree Club a success.


Outing to Kat O on 6 June 2012


Celebrating the 5th anniversary of Veneree Club

Biomedical Note

Imaging nanosensors for cell therapy

Cell therapy is emerging as a major development in human medicine, which has shown promise in a wide range of diseases and injures. However, a non-invasive assessment of cell status after transplantation is not yet available in clinical settings. An imaging approach to visualise the location, function and survival of transplanted cells repeatedly and non-invasively has been developed and further investigated at City University of Hong Kong.

Magnetic resonance imaging (MRI) is a widely available imaging modality. Thus, using MRI to evaluate treatment outcomes in cell therapy could facilitate the translation of cell therapy, especially stem cell therapies for non-curable diseases, such as Parkinson's and Alzheimer's disease.

An MRI nanosensor platform has been developed to probe cellular changes at the molecular level by responding to the micro-environment after transplantation. These molecular changes indicate the function and viability of the therapeutic cells or stem cells. The platform consists of three major components:

1. the sensitive nanosensor, which is designed to detect and respond to subtle molecular changes under physiological conditions
2. biocompatible material, which creates a constructive environment to promote and support the function of therapeutic cells
3. the sensitive and specific MRI readout for the visualisation of cellular events

For example, pH nanosensors are incorporated into the microcapsules, which are widely used to immuno-protect and deliver cells, for imaging cell survival. The pH in the micro-environment is associated with cell viability, thus the developed nanosensors monitor the pH to indicate the number of viable cells. A molecular MRI readout is chosen to report the pH changes and hence the survival of therapeutic cells. With this MRI nanosensor, we can image the location of transplanted cells and the number of surviving cells at the transplantation site. If a low number of surviving cells is observed, perhaps auxiliary treatments can be applied to salvage the cells. This would allow the evaluation and refinement of treatments in clinical settings to benefit more patients, providing a new paradigm in the age of precision medicine.

This article is contributed by Dr Kannie W Y Chan of the Department of Mechanical & Biomedical Engineering, City University of Hong Kong; with the coordination of the Biomedical Division.

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