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ContentsIssue No.44

Publication of the Chamber of Engineers

Cover Image Engineering leads the search for new life forms with drilling in Antarctica.

Editor Ing. John Pace

Editorial BoardIng. John PaceIng. Paul RefaloIng. Ray VassalloProf. Robert Ghirlando

Chamber of Engineers,Professional Centre,Sliema Road,Gzira, GZR 1633, Malta

Tel: +356 2133 4858Fax: +356 2134 7118

Email: [email protected]: www.coe.org.mt

© Chamber of Engineers 2013. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopy, recording or otherwise, without the prior permission of the Chamber of Engineers – Malta.

Opinions expressed in Engineering Today are not necessarily those of the Chamber of Engineers – Malta. All care has been taken to ensure truth and accuracy, but the Editorial Board cannot be held responsible for errors or omissions in the articles, pictographs or illustrations.

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Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemi-

cal Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil






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Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural

Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics

Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural

Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design

Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics

Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural

Aeronautical Biomedical Mechanical Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical

Chemical Civil Sustainability Design Electrical and Electronics Systems Biomechanical Photonics Software Computer Nuclear Mineral Agricultural Aeronautical Biomedical Mechanical Chemical Civil

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February 2013www.coe.org.mt

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From the Editor

From the President

Kolsterising®: Towards long lasting implants

Getting the best out of training

Postgraduate Biomaterials Research

The Gewiss ReStart - Protection without Compromise

11th Edition Malta Engineering Excellence Awards 2012

Supervisory, Control and Data Acquisition (SCADA) Project

Implementation of an Integrated SCADA and F&G System at Gasco LPG Plant

Interview with Ing. Marco Cremona

Painting without paint

February 2013 | Issue No. 444

The Engineer in Politics

The Maltese public will soon be called to choose who will run the country for the next five years. As Malta becomes more technically oriented I sometimes wonder why engineers are hardly visible in the political world. When constitutional matters were the main issue in politics it was natural that lawyers were at the forefront, and as the nation developed, economists and business consultants felt that they had to contribute by having a say in its administration. We have never yet had a warranted engineer in parliament, while it is exceptional that an engineer will contest the election or involve himself in party politics.

Lately two engineers, Mark Sammut and Ryan Callus announced that they will run for the election. They are not the first ones as in the past there were candidates for both the large parties, though this was quite unusual.

I put some questions to Mark and Ryan and also to a former candidate for the other party, who, unfortunately declined to reply as he has not been involved in politics for a very long time and is now in his eighties.

According to Ryan, politics is about politicians working for the advancement and progress of society in the best interest of the country. It is about providing a selfless service to your country for the common good. It is about common citizens who have had the privilege and honour to be democratically elected by the people to serve as their representatives in Parliament. The politician’s mandate is to reflect the people’s aspirations. This should not however be done from a populist perspective, promising everything to everyone. The politician must make decisions that are sustainable, just and for the common good. Mark adds that

the role of the individual politician is to be the voice of his constituents in parliament, raise the issues they are facing for debate, and also to propose solutions.

But what has an engineer to offer? Mark says that engineers introduce a scientific approach have a higher degree of understanding of issues such as sustainability and infrastructure than members of other professions. Ryan says that through his involvement in politics he has come to learn that politics is about finding solutions to challenges that vary in scope, nature and extent. He believes engineers tend to be more analytical, pragmatic and oriented on problem solving.

Why are persons in certain professions naturally attracted to politics, while engineers as a rule are not? Mark thinks that people like lawyers and doctors regularly meet their constituents in their normal work day, while engineers are busy on projects and in industry where such contact is rare. Ryan thinks this is unfortunate as a more balanced mix of professions is healthy. Engineers should contribute in parliament especially when debating matters such as energy where the engineer’s perspective and contribution becomes more essential.

Ryan is emphatic that engineers need politics and politics needs engineers. The same applies for public issues where it should be perfectly acceptable for an engineer to express his/her opinion or criticism as long as it is constructive and non-partisan. If engineers want to remain relevant to our society, besides their everyday role, they must voice their concerns on issues that affect or involve them or their line of work. The public still regards engineers as simply technicians and engineers must work to improve this image.

From the editorby Ing. John Pace

5February 2013 | Issue No. 44

Ing. John PaceEditor,Engineering Today

Both Ryan and Mark deny that involvement of engineers in politics would damage their career. On the contrary, says Mark, having the confidence to express yourself in the public sphere can only reflect positively on your personality.

At the time of writing this article the media is inundated with news items and comment on the PL plans on the power stations and the PN counter arguments. We have heard lawyers, dentists and journalists having their say, but engineers were notably absent. The general public is confused as the issue is sometimes far too technical for general consumption. There is also a lot of disinformation on technical issues where the public has to decide between two extreme sources of information without the benefit of a balanced and well informed view.

In other countries a technical background has proved no handicap to being at the forefront of politics. China tops the list where Hu Jintao (hydraulic engineer) and Jiang Zemin (electrical engineer) were top people. Boris Yeltsin was a civil engineer and Margaret Thatcher an industrial chemist. ET

Mark Sammut has a Masters degree in Wireless Networks and is employed as a systems engineer with a telecommunications company. He has been a Local Councillor in Gudja on behalf of the nationalist party since 2006.

Ryan Callus is deputy mayor in Siggiewi Local Council. He obtained a Masters degree in Project Management and was formerly PRO of the Chamber of Engineers.


From the President

Dear Colleagues...

by Ing. Saviour Baldacchino

Time flies and we are four weeks into 2013, preparing for the forthcoming annual general meeting (AGM), annual conference, training programs, profession profile survey, members’ events, national consultations and more.

The Malta Engineering Excellence Awards 2012, closed of the Chamber’s calendar of events for the year. Congratulations go to the award winners and to all the nominees who not only presented tough competition to their peers but also made us proud of their accomplishments.

Last year’s event was a great success in terms of the quality of the nominations, record attendance by members and their

guests, increased sponsor support and high organisation standard. This gives the organising team remarkable satisfaction and augments their enthusiasm to produce high quality events which merit the profession.

During the awards night, the Chamber was honoured with the participation of the Embassy of the United States with whom we look forward to establish stronger cooperation in the coming months. The venue was once again kindly conceded to the Chamber by His Excellency Ambassador, Ingr. Umberto Di Capua, to whom we continue to be most grateful and respectful.

Four days into 2013, the Chamber kicked off its training programme for the year with a seminar on basic acoustic concepts. The event was held at a leading hotel in Floriana. It was very well attended and the topic generated a healthy discussion on the subject. Similar events will follow throughout the year.

This was the first in a series of training activities which are being prepared for members. Some months ago, a Training sub-committee was set up to focus on the training function of the Chamber and to come up with a strategy that will position the Chamber as one of the leading training providers on the island. The undersigned is chairing the sub-committee.


Ing. Saviour Baldacchino President, Chamber of Engineers

Yours Sincerely,

Ing. Saviour M. BaldacchinoPresident,Chamber of Engineers

[email protected]://www.coe.org.mt

The next AGM is going to be held on the Thursday, 28th February 2013 at 18:00. This year, the Chamber will be introducing voting by post to elect the Executive Council. This is another initiative to encourage members’ participation, this time, in the Chamber’s statutory obligations. We still prefer to meet our members face to face at the AGM and they are encouraged to honour us with their presence and participation. Nevertheless, the postal vote should make it easier for those members who couldn’t participate in the AGM, to express their preferences and have a say in the selection of their representatives.

The voting process will be overseen by a Notary Public acting as an independent Election Commissioner. The fundamental principles of vote secrecy, anonymity and one vote per member, have been taken into account and incorporated into the voting process. Full details about the latter are being communicated to members in advance.

The topic of this year’s annual engineering conference, which is planned for the first half of May 2013, will be on biomedical engineering. Preparations for this flagship event are on the way and further details will be communicated to members in due course. A call for abstracts will be issued shortly.

Our motivation is the well being of the profession and its members. All those who share this ethos are encouraged to come forth and join the team. This is how you may invest in the future of your profession. Please send us your feedback on [email protected] on anything you would like to see happening at the Chamber.

We wish our engineering student members good luck for their mid-semester examinations. ET

25th January 2013


Kolsterising®: Towards long lasting implants by Dennis Formosa

Corrosion testing of Kolsterised® Biomedical Ni-Free Stainless Steel.

Metallic materials such as stainless steel, cobalt chrome and titanium are commonly used as biomedical implant devices to replace or fix important structural human body components, such as hip joints and bone plates. These implants restore the quality of life to millions of people worldwide. These three metal types are used interchangeably as different devices and situations call for different inherent device properties. This is because from one type to another the material properties such as wear resistance, Young’s modulus, corrosion resistance and cost all vary significantly. Cobalt chrome and titanium alloys have some advantages where it comes to corrosion resistance over common stainless steel alloys, however they cost significantly more. Hence austenitic stainless steels are extensively used to manufacture a variety of biomedical implants.

Although biomedical stainless steels came a long way since they were first used in the 20th century, reports of failed devices while in service inside patients are not uncommon. Current implants normally last only 10-20 years, of which 7% require revision surgery after 10 years of service. This short life span is often due to wear and corrosion degradation which leads to aseptic loosening [1]. Corrosion inside the human body can occur either due

to pitting or crevice corrosion and it is of great medical concern because of the elevated metallic ion release. Nickel and chrome are two constituents of stainless steel, the former is the most common sensitizing (allergy-causing) element and the latter a known carcinogen. Both are toxic when leached into the human body system via corrosion reactions. Replacing the implant is the only reliable way to solve the problem of a corroding in-service implant. This puts additional trauma on the patient and introduces extra expenses and work load on national health care system. These corrosion problems can be alleviated through surface engineering techniques such as ‘S-phase technology’.

‘S-phase’ technology, discovered in 1985 by Prof. Bell and Zhang in stainless steel has been heavily researched upon and applied for multiple industrial applications such as nuclear, automotive and food industry but not for biomedical implants [2, 3]. It includes subjecting a stainless steel component to a thermo-chemical treatment, using a carbon/ nitrogen rich atmosphere at temperatures under 500°C for extended periods of time (~10-30 hours). This process will form a carbon/ nitrogen diffused surface layer (~10-40 µm thick in depth) on the component. Kolsterising®, a


proprietary service of Bodycote International is an example of a process that produces carbon-rich S-phase. This S-phase layer improves surface-related material properties such as: corrosion, wear and fatigue resistance which are vital for biomedical implant material.

The Nickel-free alloy is a modern type of biomedical stainless steel which was designed to address problems concerning Nickel hypersensitivity. Nickel-free alloys have improved levels of tensile yield strength, corrosion resistance, fatigue strength and reduced danger of hypersensitivity in patients.

The aim of this study was to investigate the feasibility of creating corrosion resistance S-phase layers on Ni-free stainless steel. In this work two Kolsterised® stainless steels were compared: A biomedical Ni-free one against a more studied industrial grade AISI 304 one.

Characterisation experiments were performed to ensure the presence of S-phase on the surface. Figure 1 shows such an optical microscopy image of a Kolsterised® Nickel-free alloy. A featureless S-phase layer of around 30µm in thickness can be seen.

A number of tests including X-Ray diffraction, surface hardness, glow discharge optical emission, were performed to help characterise any surface changes due Kolsterising®. These tests showed that surface properties changed considerably and was concluded that an S-phase layer was present on both stainless steel alloys. Figure 2 shows improvement in surface hardness due to treatment.

Accelerated corrosion tests following ASTM standard experiments, some medically oriented were conducted. Pitting and crevice corrosion resistance were tested by electrochemical methods (ASTM F746 and standard potentiodynamic polarization) where the samples were immersed in simulated body fluid and an electrical potential applied. This accelerated test is designed to mimic corrosion behaviour response of an implanted material at in vitro conditions. Also, a 72-hour immersion ASTM G48 test in a acidified ferric-chloride solution was performed for classification purposes. This tests, intended to mimic crevice corrosion, consisted of using a jig to impress a crevice washer as shown in Figure 3 against a sample surface.

Figure 1 - Microstructure cross-section of S-phase layer formed by Kolsterising® on the Ni-free stainless steel alloy. Redrawn from [4]

Figure 2 - Surface hardness result comparison. Vickers hardness test at 100g of load. Error bars represent variation of 4 repeats from mean

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Kolsterising®: Towards long lasting implants (cont.)

The electrochemical tests both corroborated one another showing a general improvement in corrosion resistance for both metal types after Kolsterising®. As it can be seen in Figure 4, crevice corrosion (circular oriented triangle impressions) was reduced in the Kolsterised® samples.

The Kolsterising® treatment reduced the weight loss (Figure 5) of the Nickel-free alloy by more than an order of magnitude which is evident by the difference in Figures 4 (c) and (d). The AISI 304 showed no significant reduction, which was later associated with the high impurity level of AISI 304 which caused pitting (Figure 4b). One can also notice significant differences between the weight lost by AISI 304 and Nickel-free confirming the superior corrosion resistance of Nickel-free alloy.

After analysing the above results and others, it was concluded that both alloys responded well to the Kolsterising® treatment and had improved corrosion resistance. This study was published in the peer reviewed journal Surface and Coatings Technology [4].

Although this study was concerned only with corrosion behaviour, such treatments also improve wear resistance. The combination of Nickel-free stainless steel and Kolsterising®

might be a possible alternative to used Co-Cr-Mo alloys which are currently the material of

Figure 4 - Macrographs of (a) untreated AISI 304, (b) Kolsterised® AISI 304, (c) untreated Ni-free and (d) Kolsterised® Ni-free samples after corrosion testing, using the 72hr adapted ASTM G48 test in acidified ferric chloride solution. Source: [4]

Figure 5 - Average weight loss in mg for treated and untreated AISI 304 and Ni-free alloys following an acidified ferric chloride corrosion test according to adapted ASTM G48. Error bars represent variation of 3 repeats from mean. Redrawn from: [4]

Figure 3 - Simplified crevice test enclosure including (A) plunger;(B) crevice washer; (1) outer enclosure; (2) sample; and (3) threaded enclosure plug. Redrawn from: [4]


choice in hip-joint replacement. Producing cheaper high-performing articulating and non-articulating surgical implants translates into longer life and a lower health risk. It should be emphasised that before such surfaces can be utilised in the medical industry, rigorous investigations regarding the long term chemical, mechanical and biological stability of the S-phase layer need to be performed first. ET

Acknowledgements

The author would like to thank the University of Malta Research Fund Committee for the financial support and ERDF (Malta) for the financing of the testing equipment (Ref. no. 012 and Ref. no. 018). Special thanks also go to Mr. R. Hunger at Bodycote Hardiff GmbH, Germany for performing the Kolsterising® treatments and Böhler Edelstahl (AT) for supplying the materials. In addition, the author would like to express his appreciation to Dr J. Buhagiar, the staff at the Department of Metallurgy and Materials Engineering, the Chemistry department and correspondents at the University of Birmingham.

References

[1] B. D. Ratner, A. S. Hoffman, F. J. Schoen, and J. E. Lemons, Biomaterials Science: An Introduction to Materials in Medicine, Chapters; 2.9, 7.7. London: Elsevier Academic Press, 2004.

[2] H. Dong, “S-phase surface engineering of Fe-Cr, Co-Cr and Ni-Cr alloys,” International Materials Reviews, vol. 55, pp. 65-98, 2010.

[3] M. K. Lei and X. M. Zhu, “In vitro corrosion resistance of plasma source ion nitrided austenitic stainless steels,” Biomaterials, vol. 22, pp. 641-647, 2001.

[4] D. Formosa, R. Hunger, A. Spiteri, H. Dong, E. Sinagra, and J. Buhagiar, “Corrosion behaviour of carbon S-phase created on Ni-free biomedical stainless steel,” Surface and Coatings Technology, vol. 206, pp. 3479-3487, 2012.

Dennis FormosaGraduated as a Mechanical Engineer,University of Malta,Currently reading for a Doctoral Degree at the University of Birmingham (UK)

Kolsterising®: Towards long lasting implants (cont.)

What do we hope to achieve when we send staff for health and safety training? Do we really know?

Very often training is seen merely as a way to fulfil legal duties, and it is true that legislation in most countries imposes requirements on employers to ensure that their staff are properly trained in various aspects of health and safety. The big question is however, will the training that we arrange for them fulfil these legal duties - and perhaps as important provide us and them with practical benefits?

To answer these questions we need to go back to basics and remind ourselves of the purpose of training. BusinessDirectory.com defines training as, “Organized activity aimed at imparting information and/or instructions to improve the recipient’s performance or to help him or her attain a required level of knowledge or skill”. In other words, training should enable participants to improve their performance and/or skill. This means that people who undergo training should be able to do something after the training that they could not do before it!

Training is also one of the elements of “competence”. It is often said that competence, a term used frequently in health and safety, is a combination of four elements; training, experience, skill and authority. Training is therefore essential to staff working towards competence.

Having gained a better understanding of what training really is and what it should be designed to achieve, we can now take certain actions to help ensure that the training we obtain will be effective. These actions include the following:

• Take time to decide on the learning outcomes required before deciding on a particular training course.

• Decide whether these learning outcomes can be achieved within an off the shelf course syllabus, or if a tailor-made course is required. Speak to potential course providers at this stage.

• Decide how important external accreditation is to you and to the delegates, (externally accredited courses eg. NEBOSH, IOSH etc etc require the course-providers to meet certain standards and delegates are assessed independently. Successful candidates are awarded a qualification from the awarding body rather than the provider).

• Check the standards, previous track-records, and accreditations of potential training course providers, and check that their methods and their approach to training suit your company.

• Check to see how the delegates’ learning will be assessed.

• Training involves time and expense; it is an investment in staff, so it is important to get it right! Taking a little care at the planning stage, and following the suggested actions made above, can help ensure that you and your staff achieve the best results and benefit in the ways you hoped.

by Chris Hudson

Getting the best out of training

Institute of Health & Safety99 Mill Street, Qormi QRM3100, Malta

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The department’s labs have over the past year been upgraded with state of the art equipment, part financed by ERDF (Malta) through the project: “Developing an Interdisciplinary Material Testing and Rapid Prototyping R&D Facility” (Project Ref. no. 012).

In recent years the DMME has turned its attention towards the vibrant, emerging field of biomaterials. Biomaterials are by definition biological or synthetic substances which can be introduced into body tissue alone or as part of an implanted medical device. The main requirement of a biomaterial is that it is fully biocompatible with living body tissue. In addition a biomaterial should not degrade in a manner that is detrimental to the patient, and should in general comply with the various constraints set out by the medical professional in tandem with the engineer.

At postgraduate level the DMME is currently supporting the research of two full time students in this field, the authors of this article. Malcolm is reading for a Ph.D. focusing on in-vitro testing of a surface-hardened Co-Cr-Mo alloy, whilst Luke is reading for an M.Sc. by research focusing on modified formulations of a dental root-end filler known as MTA (Mineral Trioxide Aggregate). This article will explore these projects.

“In-vitro” Studies of Surface Hardened Biomedical Co-Cr-Mo Alloys used for Orthopaedic ApplicationsMalcolm Caligari Conti(The Department of Metallurgy and Materials Engineering, Faculty of Engineering and The Department of Anatomy, Faculty of Medicine and Surgery)

The Ph.D. research is conducted as a joint project between the DMME and the Faculty of Medicine,

and is supervised by Dr. Joseph Buhagiar and Dr. Pierre Schembri Wismayer MD. The project aims to test the in-vitro biocompatibility of Cobalt Chrome when Kolsterising® is applied. Kolsterising® is a low temperature carburizing process that can be used on medical alloys due to the hardness it imparts to the surface, without reducing its corrosion resistance. Kolsterising® is a proprietary surface hardening treatment by Bodycote GmbH.

Orthopaedic applications to material science are increasingly becoming one of the most important areas of research, especially during the past fifty years, over which period of time materials intended for biomedical purposes have evolved through three different generations [1]. In this regard, the latest statistics show that the European market for artificial knee and hip joints alone is worth €23.1bn, with €8.6bn being spent on artificial devices annually [2,3]. Smith et al. [4] have reported that; orthopaedic metal-on-metal implants (Figure 1) suffer from high failure rates. Thus by increasing the hardness of Co-Cr-Mo alloy by Kolsterising®,

Postgraduate Biomaterials Research

The Department of Metallurgy and Materials Engineering (DMME) is one of six departments which make up the faculty of engineering.

by Malcolm Caligari Conti and Luke Formosa

Figure 1 – Superposition of a metal-on-metal implant onto an X-ray image of a hip. Adapted from [13,14]

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and therefore making them more comparable to the hardness of ceramics, one hopes to achieve an articulating surface which is both biocompatible and corrosion-wear resistant.

The objective of this research is to analyse the biocompatibility of Kolsterised® cobalt-chromium-molybdenum alloys, and to characterise the material surface in order to show the advantages gained by using the Kolsterised® material relative to the original untreated alloy, and other materials. This work will be conducted on four approaches including: (1) material characterisation, (2) in-vitro corrosion testing, (3) in-vitro corrosion-wear testing, and (4) biological testing conforming to ASTM F748-04.

From preliminary results in the first few months of the Ph.D. study, S-phase1 formation was observed on the Kolsterised® material. The actual thicknessof the S-phase layer, 13.4μm, was confirmed by SEM analysis of the etched

sample. Although thinner than the Kolsterising® layer normally created on stainless steels it is still thick enough to protect the underlying softer material. Preliminary nano-indentation tests show that the hardness of the S-phase layer on Kolsterised® Co-Cr-Mo is 17.38 ± 0.30GPa (99% confidence limits) which is 2.5 times greater than the hardness of the untreated material which has a hardness of 6.78 ± 0.08Gpa (99% confidence limits).

Cell viability testing and other biocompatibility tests will also be carried out using both mouse and human osteoblast and pre-osteoblast cell lines in the laboratories of the Department of Anatomy which were recently refurbished using funds from ERDF project 081. This will then pave the way for future research to be carried out, in order to ensure that the Kolsterised® Co-Cr-Mo system is proven to be biocompatible, permitting its use as a material for hip and knee replacements as well as in other biomedical components.

Postgraduate Biomaterials Research (cont.)

1 A supersaturated layer which generally retains biocompatibility, whilst imparting a greater hardness to the material surface.


The Investigation of a Novel Biomaterial for use in Dental ApplicationsLuke Formosa(The Department of Metallurgy and Materials Engineering, Faculty of Engineering and the Department of Restorative Dentistry, Faculty of Dental Surgery)

This M.Sc. research is a joint project between the DMME and the Department of Restorative Dentistry, Faculty of Dental Surgery of the University of Malta and is supervised by Dr. Bertram Mallia and Prof. Josette Camilleri. Mineral Trioxide Aggregate (MTA) was introduced in 1995 as a dental material for use as a root-end filler during surgery [5] and is

composed of 80% Portland cement and 20% bismuth oxide [6]. Portland cement, the bulk of the material, provides mechanical strength and can develop its physical properties even in a humid environment (such as the human body). The bismuth oxide is needed to increase the radiopacity, which makes the material distinguishable from body tissue on X-rays to aid post-operative identification.

The main advantage of MTA is that it is bioactive - it hydrates in the presence of water to produce calcium hydroxide, which upon reaction with tissue fluids such as blood produces a surface layer of bone-like hydroxyapatite [7]. These appear as spheroidal particles when viewed



under the electron microscope (see figure 2). Being bone-like, this layer gives MTA very good biocompatibility and excellent sealing ability [3]. However its disadvantages include a long setting time (around 3 hours) and poor resistance to washout. Washout is the tendency of freshly placed cement to disintegrate upon premature contact with liquid (such as blood in the surgical site) [8]. This research aims at investigating novel MTA-based materials that attempt to address these shortcomings.

The new materials include MTA mixed with a proprietary anti-washout gel to impart washout resistance, and MTA mixed with a dental-light curing resin or chemically-curing resin in place of water, to reduce the setting time. Tests conducted to date indicate that the setting time of the MTA with light-curing resin is just 20 seconds under high-intensity light, whilst with chemically curing resin the MTA sets within 22 minutes. This is a significant improvement over the 3 hours reported for MTA.

A novel method for evaluating washout resistance was developed for this research and has been accepted for publication by the International Endodontic Journal [9]. The tests revealed that the anti-washout gel completely eliminated washout. This compared favourably to normal MTA that lost up to 10% of its mass due to washout under the same experimental conditions.

A series of tests are being carried out to characterize and study the hydration mechanisms of the novel materials, including scanning electron microscopy (SEM) with X-ray energy dispersive analysis (EDX), X-ray diffraction (XRD) and Fourier-Transform Infra-red (FTIR) analysis.

Furthermore, the materials are being tested for their suitability as dental root-end fillers following ISO standards for testing dental materials (namely ISO 4049 (2009) [10], ISO 9917 (2007) [11] and ISO 6876 (2002) [12]). These tests include assessment of radiopacity, compressive strength, calcium ion release pH, fluid uptake, porosity, micro- and nano-hardness, Young’s modulus, and the strength with which they adhere to extracted human teeth, measured by means of push-out tests, in each case in simulated body fluid (a synthetic water-based solution identical to human blood plasma).

Conclusions

Biocompatibility, biomaterials, bioengineering and biotechnology are all fields in which research requires the efforts of multiple disciplines in order to produce a viable and cutting edge result which may one day lead to an enhanced product. Working in this area consequentially becomes an experience the

Figure 2 – Micrograph (20,000x zoom) showing apatite spherulites on the surface of an MTA specimen after it had been immersed for 28 days in simulated body fluid (a synthetic analogue of human blood plasma)

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results of which translate directly to the potential for achievement of a better quality of life. ET

Acknowledgements

Malcolm Caligari Conti’s Research is sponsored by Bodycote GMBH.

Luke Formosa’s research is funded by the Strategic Educational Pathways Scholarship (STEPS) (Malta). The scholarship is part-financed by the European Union – European Social Fund (ESF) under Operational Programme II – Cohesion Policy 2007-2013, “Empowering People for More Jobs and a Better Quality of Life”

References

[1] M. Navarro, et al., “Biomaterials in orthopaedics,” J. R. Soc. Interface, pp. 1137-1158, 2008.

[2] OECD, “Health at a Glance: Europe 2010,” (2010).

[3] Healthcare Blue Book. (2012, 28/02). Total Hip Replacement. Available: http://healthcarebluebook .com/page_Results .aspx?id=28&dataset=MD

[4] A.J. Smith et al., Failure rates of stemmed metal on metal hip replacements: analysis of the Data from the national joint registry of England and Wales” The Lancet 379, (2012) 1199-1204


Malcolm Caligari ContiObtained his Bachelor’s Degree in Mechanical Engineering in 2011,University of Malta,Currently reading for a Ph.D. in Biomaterials

Luke FormosaObtained his Bachelor’s Degree in Mechanical Engineering in 2011,University of Malta,Currently, reading for an M.Sc.by research in materials

[5] Torabinejad M., Hong C.U., Lee S.J., Monsef M. and Pitt Ford T.R., “Investigation of mineral trioxide aggregate for root-end filling in dogs”, Journal of Endodontics, vol. 21, pp. 603-608, 1995 [6] Torabinejad M. and White D.J., “Tooth filling material and use”, US Patent Number 5,769,638 (1995)

[7] Sarkar N.K., Caicedo R., Ritwik P., Moiseyeva R., Kawashima I., “Physiochemical basis of the biologic properties of mineral trioxide aggregate”, Journal of Endodontics, vol. 31, pp. 97-100, 2005

[8] Wang X., Chen L., Xiang H. and Ye J., “Influence of anti-washout agents on the rheological properties and injectibility of a calcium phosphate cement”, Journal of Biomedical Materials Research Part B: Applied Biomaterials, Vol. 81, Issue 2, pp. 410-418, 2007

[9] Formosa L.M., Mallia B. and Camilleri J., “A quantitative method for determining the anti-washout characteristics of cement-based dental materials including mineral trioxide aggregate”. International Endodontic Journal [in press], 2012.

[10] International Standards Organization. Dentistry: Polymer-based restorative materials. ISO 4049, 2009. [11] International Standards Organisation, “Dentistry – Water-based Cements”, BS EN ISO 9917-1, 2007.

[12] International Standards Organisation, “Dental root canal sealing materials”, BS EN ISO 6876:2002

[13] http://www.childrenhealthwatch.com/wp-content/uploads/2010/09/wpid-1285631496_hip-resurfacing.jpg (viewed: 14/04/2012)

[14] http://www.qmtmag.com/images/BHR-device.jpg (viewed: 14/04/2012)

The Residual Current Device

The RCD, an electrical wiring device that protects both life and installation, but how many of us take the unit for granted? How many of us perform a periodic test of the device?

A survey performed in Italy of 1000 households showed that 98% of users were confident that their RCD was operating correctly. However, only 42% of those same households knew of the test button on the RCD. More staggeringly, less than 25% of users carried out a test at least once!

So, how safe is the RCD?Regular use of the Test button, although unpractical is advised to ensure a high level of safety. If the RCD does not trip when the button is pressed, it is necessary to replace it.

All manufacturers strongly recommend the regular use of this test button.

So how do we ensure protection?

To increase the safety level in our electrical systems and to ensure that the installed RCD’s fulfil their protection function, it would be advisable:

• To free the end-user from the obligation to test the RCD, because carelessness and the lack of knowledge can result in the device becoming inefficient and therefore unsafe.

• To provide the service of sending a warning message to the user if and when a fault occurs.

The use of devices with automatic test represents a real solution to the problem of the reliability of the protection devices.

The Solution: “ReStart Autotest”

The ReStart Autotest by GEWISS the only protection device which:

• Carries out the automatic test every thirty days• Carries out the periodical check without cutting

the power supply to the installation, this thanks to a by-pass circuit.

• Guarantees the automatic reset of the electrical system when the electrical power cuts off because of a sudden voltage change or a thunderstorm.The ReStart Autotest will reset the current in less than 10 seconds, after first performing an insulation test of the the circuit. In the case of permanent failure in the circuit, the device will remain open circuit and a red warning light will indicate.

• Provides a warning status of long tripping time and welded contacts via couloured LED indicators that can also generate a warning message to be relayed through an auto dialler.

The Gewiss ReStart is available in both two-pole and the four-pole versions, for applications within the domestic, industrial and commercial fields.

The Conclusion

The use of devices equipped with Autotest guarantees the total real safety of the system, and:

• Guarantees the full functionality of the RCD• Allows the user to enjoy a continuous

uninterupted service during testing• Removes the the faulty RCD’s from installations,

thus offering total safety for people and properties.

The Gewiss ReStartProtection without Compromise

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Another year has passed since the 10th Edition of theMalta Engineering Excellence Awards (MEEAs).

11th Edition

Malta Engineering

Excellence AWARDS2012

An evolving event for an evolving profession

by Dr. Daniel Micallef

Last year, in issue 40 of the Engineering Today (found at www.coe.org.mt/images/Engineering-Today), I had written an article on the past, present and future outlook of the MEEAs. This time around, the MEEAs have evolved in various ways.

The 2012 MEEAs event was very well attended and this reflects the continuous growth of the Chamber of Engineers. The winners of the 2012 awards were the following:

1. Industrial Excellence Award - Hoter Ltd.2. Leadership Award - Ing. Charles Cuschieri3. Lifetime Achievement - Prof. Joseph Mifsud

To avoid repetition, the reader is encouraged to visit the CoE website http://www.coe.org.mt/news-a-events for a complete description of the event.

As with the 2011 awards,in the MEEAs of 2012 there was strong competition between the nominees. Also, it was observed that the quality of the proposed projects for the Industrial


Excellence Award has increased substantially since the 2011 awards. This is a direct proof that our profession is reaching international standards and is something we need to foster and keep up. It is clear that Maltese industry is focusing on engineering excellence thus making the role of engineers fundamental. The professional engineer is no longer a luxury that few can afford but rather a fundamental contributor to maintain a competitive edge. This is, after all, the message that the Chamber of Engineers strives to communicate to society.

For the MEEAs of 2012, the ‘Innovation Award’ has been renamed the ‘Industrial Excellence Award’. The reason for this change is that we wanted to have an award which strictly promotes industrial entities and companies.

From left to right: Dr. Daniel Micallef (Activities Secretery, CoE), Ing. Charles Cuschieri (Leadership Award), Prof. Joseph Mifsud (Lifetime Achievement Award), Ing. Marco Cremona representing Hoter Ltd. (Industrial Excellence Award), Lieutenant Commander William Woytyra (US Embassy) and Ing. Saviour Baldacchino (President, CoE)


High level projects awarded at Malta Engineering Excellence Awards 2012

Professor Joseph Mifsud, Ing. Carmel Cuschieri and Hoter Ltd were the proud winners of the 11th edition of the Malta Engineering Excellence Awards (MEEA) 2012, which was held recently at St John’s Cavalier.

Over 250 engineers and guests attended this year’s ceremony, which is organised annually by the Chamber of Engineers (CoE). The MEEAs are an opportunity to recognise the capabilities of engineers in Malta, and is a flagship event of the CoE. CoE President Ing. Saviour Baldacchino and Lieutenant Commander William Woytyra, representing the United States Embassy presented the awards.

The award for Industrial Excellence was awarded to Hoter Ltd, run by Ing. Marco Cremona of Sustech Consulting. Ing. Cremona has invented, built and tested the HOTER process leading to the development of the world’s first sewage-to-potable water plant for hotels and large commercial buildings.

The Leadership Award went to Ing. Charles Cuschieri. An engineer by profession,

Ing. Cuschieri founded his consultancy firm in 1979 together with the late A.G. Camilleri CEng FIEE. In June 1982, he joined the University of Malta as the youngest full time lecturer at the time. He lectured in analogue and digital electronics and later in Power electronics. In 1989 he left lecturing to continue with his consultancy.

Professor Joseph Mifsud was awarded the Lifetime Achievement Award. Prof. Mifsud began his engineering career at Malta Drydocks when he joined the ship repair yard as an apprentice. His academic studies progressed to a Mechanical Engineering degree at Surrey University. Returning to Malta, he joined the Mechanical Engineering Department, where he was promoted to senior lecturer and later to Head of Department, a post he kept until retirement.

During his address, CoE President Ing. Baldacchino noted his satisfaction that the MEEAs give the Chamber the opportunity to recognise engineering excellence in the presence of the largest gathering of professional and prospective engineers. Ing. Baldacchino pointed out that the Awards are publicised

both locally and abroad, with the winners given exposure by the European Federation of Engineering Assocations (FEANI) and the World Federation of Engineering Organisations (WFEO), of which the Chamber is an active member.

In conclusion, he congratulated both the nominees and winners for their high level submissions and encouraged all nominees to continue with their excellent work. “Every one of them is making us proud of their engineering contributions,” he said.

This year’s edition of the MEEAs 2012 was supported by Bank of Valletta, GO plc, STMicroelectronics Malta Ltd and Dark Dragon Media Ltd.

(cont.)

2012


The criteria of this award were based on the European Foundation for Quality Management (EFQM) Excellence model (details can be found at www.efqm.org). This has been applied on the basis of a project carried out by the industrial entity. The method simply involves the consideration of ‘Enablers’ such as leadership, people, strategy etc. and ‘Results’ which for the case of these awards were the achieved project results. On the basis of the EFQM model, a number of criteria were set and a score attributed by a panel of judges to each criteria. The use of this methodology has two particular benefits:

1. It ensures that overall excellence can be gauged with a standard and uniform approach

2. It encourages industrial entities to strive for excellence. The end results depend on the enablers which are mostly engineers. This not only promotes the value of the engineer but also encourages companies to view professional engineers as a revenue generating human resource.

The criteria for the Leadership Award were targeted to promote the individual engineer for good leadership skills. In the past, the leadership award was also open to industrial entities. The disadvantage of this was that it was difficult to compare leadership from an individual and leadership of an entity. There was therefore room for improvement in order to ensure an easier judgement.

The Lifetime Achievement Award was kept unchanged from previous years. The criteria for this award can be summarized as follows:

1. Contribution to the engineering profession2. Impact on Maltese society

Ing. Marco Cremonarepresenting Hoter Ltd., winner of the Industrial Excellence Awards

Ing. Charles Cushieri, winner of the Leadership Award

Lieutenant Commander Woytyra presenting the Lifetime Achievement Awardto Prof. Joseph Mifsud

The conference will be held 25th April 2013. This year, the theme of the conference will be bio-medical engineering. The venue is still to be confirmed.

The objective of this conference is to provide insight to engineers and other professionals on this ever growing branch of engineering. The health sector has no doubt made great leaps forward to the well being of people. Little is however mentioned about the engineering knowledge required to put medical science into practice. In this conference, experts in the field swill shed light on some of the technological developments in the field. In Malta, there are various opportunities in which engineers can be involved in bio-medical engineering due to the fact that the field requires the input of other branches of engineering.

The topics which will be addressed include but are not limited to: CT, MRI and Ultrasound technology, implants, biomechanics, biomaterials and medical imaging.

The conference will be particularly appealing to:

• Engineers• Medical doctors• Pharmacists• Entrepreneurs• Scientists• Students• Academics• Industrialists• Consultants

Instructions for Abstract Submission:

Authors are invited to submit an abstract to the organizing committee by email or by post. A limited number of high quality abstracts will be chosen for an oral presentation and a full paper will be required for publication in the issue following the conference of the CoE’s magazine Engineering Today.

The abstract should not exceed one A4 page and should be typed in Times New Roman-12pt., double spaced. The Authors should clearly highlight the objectives, results and outcomes. Authors name, affiliation and address (including e-mail) should be mentioned in the abstract. The following formatting should be used for the names and affiliations:

Title of the Abstract (14 point with Bold face)Corresponding Author, Author (12 point with italics with bold face)Full Address of the Author (12 point with italics)Any figures are to be prepared with high resolution.

The deadline for abstract submission will be 4th March 2013.

The Chamber of Engineers is proud to announce the launch of its 22nd Annual Conference...

“Engineering: the Backbone of Healthcare”

Further information may be obtained from:

Chamber of Engineers127, Professional Centre, Sliema Road, Gzira GZR 1633

Tel: 2133 4858 - email: [email protected]


(cont.)

2012

Dr. Daniel MicallefActivities Secretary, The Chamber of Engineers

3. Research that expands the engineering field4. Contribution to engineering education

Thankfully, there are many professionals who fulfil these criteria and therefore, year after year, decisions on this award are painstakingly difficult.

Given the ever increasing competition for the MEEAs, the Chamber of Engineers is committed to refine further the award criteria and requirements. This will stimulate further competition and hence improve the overall quality. The Chamber of Engineers is also

considering adding more awards in order to reach out for the ever increasing diversity of our profession. We all look forward to see you in our events and encourage you to participate and be active. ET

The event was ably compered by television presenterStephanie Spiteri


At the same period, advanced micro processor protection relays were more available in the market and these were replacing the electromechanical type protection relays. Moreover computers were also being implemented in substation automation systems. In view that such automation systems enhance data acquisition and enable engineers to analyse and control substation equipment, Enemalta embarked to install Substation Control Systems in the new Distribution Centres being planned at that time. The first Substation Control System was installed at Mellieha Distribution Centre followed by Kirkop, Valletta and Marsascala Distribution Centres. With the positive experienced gained from these first Substation Control Systems Enemalta decided that all new Distribution Centres must be equipped with such automation. Moreover an engineering analysis was carried out to check the feasibility to also install automation systems in old Distribution Centres. This study concluded that having such automation systems in all Distribution Centres would give the necessary tools to assist Enemalta engineers in the planning of the HV network development, and would reduce restoration time when power interruptions occurs. With eighteen Distribution Centres around the Island and two Power Stations it was required to have an overall system to communicate with all the automation systems installed in each Distribution Centre. A SCADA system was required to achieve this goal. A tender was issued in December 2006 and following lengthy evaluations a successful bidder was chosen.

SCADA Project Implementation

Enemalta is presently at the final stage of installing a SCADA system, this being part of the multi projects being implemented in the Power

System network. The SCADA system provides a complete graphical view of the 132kV, 33kV and 11kV network from a central control room. This includes a detailed substation single-line display for all Distribution Centres located in Malta, Comino and Gozo together with Marsa and Delimara Power Stations.

The information in the SCADA servers is updated automatically from the site Remote Terminal Units (RTU) or the Substation Control Systems (SCS) that are installed in each Distribution Centre and Power Station.

The Medium Voltage network, consisting of about 1400 11kV/400V substations located throughout the Maltese Islands, will be modelled in the SCADA system and this will be used for keeping as an operated image of the MV network. Since there is no data acquisition from the distributions substations, data will be entered manually.

The SCADA system provides remote control of breakers and isolators that are installed in Distribution Centres. Furthermore transformers tap changers, used to correct voltage automatically are also operated remotely from the central control room. In addition to this the control room engineers, through the event

As the Maltese Power Network continued to expand in the 1990s due to load growth,Enemalta felt the need to look into substation automation systems.

Supervisory, Control and Data Acquisition (SCADA) Project

by Ing. John Caruana

Detail of SCADA system graphical representation


Supervisory, Control and Data Acquisition (SCADA) Project (cont.)

and alarm handling of the SCADA system, are made aware of disturbances in the network and also be alerted with important events that may occur, such as tripping of circuit breakers, following a fault on the network.

Dynamic Network Colouring is used by the SCADA system to display the electrical state of all power lines, cables and equipment in the network. This will assist the control room engineers during normal switching operations, faults and supply restoration.

All alarms, events, measurements and operators actions are documented in a historical archive. This data will assist engineers when planning switching operations and reinforcement projects on the high voltage network.

The SCADA also includes a switching order management system that enables an interactive definition, pre-implementation testing and operator controlled execution of switching orders directly from the control room. An outage reporting system is also implemented. The outage reports give relevant statistics suited for an electrical distribution company. Outages are stored and further information

can be added such as classifications, reasons of outage and outage descriptions. The stored data from different outage reports then can be merged to obtain key performance indicators such as Customer Minutes Off Supply, System Average Interruption Duration Index, etc.

The project implementation commenced in August 2009 and extends on 3 years of continuous activity consisting of four phases where all major works are carried out by Enemalta engineers and technicians assisted by ABB engineers.

Phase 1 included the system design by ABB and system overview training for Enemalta Engineers.

In Phase 2 Enemalta engineers commenced with the implementation building of the graphical displays through data engineering using the ABB software provided for this purpose. Together with this activity, site engineers and technicians were working to compile the necessary data and implement the necessary wiring adaptation for the 33kV and 11kV switchgear. Once wiring adaptation and software engineering was finalised in each Distribution Centre, the necessary tests were carried out to confirm the functionality of the SCADA system. Thus the first implemented Distribution Centres were providing real time data acquisition and control.

Phase 3 provided the continuation of the site RTU installations and switchgear wiring adaptation together with further data engineering, testing, commissioning and adding further on-line Distribution Centres.

Phase 4, being carried out this year, will conclude the implementation of the project

Substation Remote Terminal Unit (RTU) installation


thus project will be fully operational and handed over to Enemalta who will be responsible for the operation and the upkeep of the SCADA project.

Load Shedding

Traditionally load shedding to stabilise the network following loss of generation or major network, was carried out at the Power Stations outgoing feeders. Now, with the SCADA project and the substation automation

systems installed, the Load Shedding is being implemented at the Distribution Centres level. This required implementation works in the SCADA system and in the RTUs or Substation Control Systems installed in each Distribution Centre. In each Distribution Centre Under-Frequency relays were installed to monitor the frequency and, if the frequency falls below a set threshold, a trip signal is sent to the substation automation. The SCADA system has a load shedding matrix for feeders and frequency levels. This matrix decides which feeders at 11kV level are tripped when a trip signal is received from the frequency levels. With this Load shedding system shedding loads is more flexible such that the minimum load required is only disconnected to re-establish the electrical system stability in the least minimum time possible.

Future Development of the SCADA Project

In the coming years more Distribution Centres will be built and commissioned, these will also be integrated with the SCADA project.

The electricity interconnector between Malta and Sicily will also be integrated with the SCADA project thus it assists in the control of power exchange between the two islands.

Substations at 11kV levels may also be integrated into the SCADA project but these required extensive switchgear works before such an integration can be implemented. ET

33/11kV switchgear wiring adaptation

HMX after modification

Ing. John CaruanaManager Network Maintenance, Distribution Department,Enemalta Corporation

ESI introduces TIA PortalThe cutting edge automation and drive technology from Siemens.

Building · Manufacturing · Water · Food & Beverage · Automotive · Marine · Pharmaceutical · Oil & Gas

With Totally Integrated Automation [TIA], Siemens is the only vendor of a uniform spectrum of products and systems for automation in all industrial sectors – covering the field level,

production control level up to linking to the company management level.

41, Dawret il-Wied, Mosta, MST 2324, Malta. Tel: +356 2141 0381 Fax: +356 2143 6981

Gasco Energy’s LPG marine terminal, storage and bottling plant started operation in July 2012. This facility has a storage capacity to 4800 metric Tons of LPG. The storage is divided into six bulk underground storage tanks. The supply of gas is received from the vessel moored to a jetty via a pipeline some 1.2km away.

ESI (Malta) Ltd were responsible to supply, install, software program, test and commission a SCADA control system and a Fire and Gas detection system (FGDS) for this plant.

The SCADA system is based on a Siemens S7-300 PLC with a Client/Server architecture and Web Clients. It controls and monitors various parts of the plant; LPG tanks and valves, pumps and compressors, electrical switchgear. The FGDS is fully integrated in the SCADA.

The heart of the system is the PLC, an S7-319-3PN/DP. Five other sub-panels house the remote I/Os as PROFINET-IOs. The PROFINET-IO system is distributed over an area of 30,000m2. The system includes over 500 input/output points. High level integrated communications over MODBUS is made with a Dräger fire and gas detection system, tank instrumentation and electrical energy meters.

The fire and gas detection system is based on a Dräger REGARD panel and has 50+ field devices connected including UV/IR flame detectors, LPG gas detectors, manual call points, sounders, beacons, et.

The client requested to have maximum flexibility in the operation of the plant which required that all the possible combination of the six tanks filling, emptying and transfers would be available at the press of a button. ESI came up with a menu and icon driven SCADA, which the client accepted due to its flexibility and ease of use. This had to be programmed into a cause and effect matrix defining all 118 possible selections. During software tests and actual plant commissioning each selection was tested individually to guarantee correct operation. Additionally, an extensive context sensitive help system enhances the ease of use for the operators.

The project is valued at more than €500K and was completed on time in July 2012. The plant will be filling around a million cylinders a year.

Implementation of an Integrated SCADA and F&G System at Gasco LPG Plant

Engineering for Science and Industry (Malta) Ltd.41, Dawret il-Wied, Mosta, MST 2324, MaltaTel: +356 2141 0381 - Fax: +356 2143 6981

Web: www.esimalta.com

Screen shots’ illustrating samples of the software application ESI implemented at Gasco

RAYAIR Automation Ltd.KW23G, Corradino Industrial Estate,Paola

Tel: (+356) 2167 2497 Fax: (+356) 2180 [email protected]

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The Hotec Process.

by Ing. John Pace

Interview with Ing. Marco Cremona

The Hotec Process was the winner of the Engineering Excellence Award for Industrial Excellence for 2012. Engineering Today interviewed Ing. Marco Cremona him on this process, which he pioneered.

ET: You are a well known figure following your conquest of Everest and your work in Sri Lanka after the tsunami. But tell us something about your background as a hydrologist.MC: I graduated in Mechanical Engineering in 1992 and my final year project at University was the design of a solar powered reverse osmosis unit. I made contact with Panta Lesco who at that time were installing the first reverse osmosis plants in hotels and my first job was with them installing and servicing these plants. In 1995 I attended a Masters course in Hydrology, which

is the science of water in its wide context, rain water, wells, sewage, etc. I was then involved in leading a team in water treatment projects, and was also involved in Environment Impact Assessment of certain large projects including government sewage treatment projects. In 2002 I started as a private consultant in water and sewage matters.

ET: What was the origin of the Hoter process?MC: The idea started in 2005. In some countries, typically Malta, potable water is not abundant. It has to be extracted or produced by desalination and then distributed through the piping system. So the consumer is supplied with high quality water, but most of this water is used for toilet flushing, laundry, watering plants, etc, which does not need to be potable water. After use this water becomes a liability, and you have to provide for its disposal. It is no longer permissible to dump this waste in the sea so it has to be treated. The whole system is therefore extremely inefficient. So I have looked at hotels which use large amounts of water and this justifies a two stage process: The first process purifies the waste water and makes

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MCST Research & Innovation Programme 2006

HOTER: Development of an innovative wastewater recycling process for hotels/ large commericalbuildings / isolated communities for environmental protection and cost recoveryClosing the water loop: 70 - 80% on site water recycling

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Interview with Ing. Marco Cremona (cont.)

it suitable for toilet flushing, irrigation and maybe swimming pools etc, and that will utilize 40 or even 50 percent of the waste water as second class water, so the quality of the water produced is of the same standard as what is needed. It does not make sense to treat all the waste water and throw away 50 percent of it. It is no longer sewage, but treated effluent. By purifying this water to potable quality it can be used not only for drinking, but also for showers and washhand basins, where the regulations state that it has to be of potable quality. And that is what the Hoter process does.

ET: What is innovative in this process?MC: The process is a combination of the two processes, sewage treatment and water purification in the context of a single building, that is not, for example, the public water supply. Hotels are an ideal situation, where the nature of the waste water is consistent and the volume of water involved is predictable, even if it varies with the season. With hotels you have to study the volume of the waste water over the whole year and size the system accordingly. You also have to determine the use of potable and second class water. The system has to be compact and also energy efficient. It has to be cost effective and compare with the available alternatives, such as a reverse osmosis unit to provide drinking water. The advantage of the

system is that you will reuse some 85% of the water – you will still have to have a source to replenish the other 15% - and another advantage is that you do not have a discharge into the public sewer system. We do not have a sewage tariff in Malta, but in other countries sewage has to be paid for according to its use, applying the Polluter Pays principle. So there is the double saving in water supply and sewage charges.

This looks good on paper, but I carried out a project to prove the system. I applied and was given a grant from the Malta Council for Science and Technology and developed and carried out a project at a particular hotel, where I treated part of the sewage, about 10%, equal to about 15 tons a day, and tested the performance of the plant over a whole year. My partner in the project was the Department of Public Health, which is a good thing, as the main obstacle was the acceptance that the quality of the water is guaranteed. I believe that this is the world’s first case of this combined system under one roof, where potable water is produced from sewage.

This system is not specifically designed for Malta; in fact it is more suited to other places where access to public water supply is more difficult or where sewage charges apply.

ET: What does the system look like?MC: The first stage is buffering, where there is a storage of the untreated sewage. This is because the flow is very variable, being high in the morning and early evening, low at other times and very low during the night. The process ideally works with constant flow. A screen removes solid objects and then there is a biological process where the sewage is treated by means of bacteria which basically need two requirements, air and food, the latter being the

Ing. Marco Cremona checking the biological treatment process of HOTER

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sewage itself. Air is provided by aeration using compressors, and a population of bacteria is maintained to digest the sewage. As long as sufficient air is provided the system works well and there are no smells.

The resulting liquid contains large amounts of suspended solids, and is brown in colour. Instead of a settling tank as in large sewage works, a membrane filter is used whose pore size is such that bacteria does not go through and the resulting liquid is clean water. This membrane is not the same as in reverse osmosis as dissolved solids are not removed, but the water is free of bacteria and of suspended solids, and is suitable as second class water.

The second stage is to produce potable water from this second class water, and it is here that reverse osmosis is used. This is more efficient than using reverse osmosis to produce fresh water from sea water, as the amount of dissolved solids is much less and the amount of water dumped is proportionally less.

In the first stage some 99% of the sewage is converted to second class water, while in the second stage I have achieved a production of 75 % of the feed water into potable water. An overall achievement of 85% reuse is the end result of the two processes. The process is flexible as the use of second class water varies with the season, for example if more irrigation is used in summer.

ET: Is it safe to drink treated sewage?MC: The standard of the water from the reverse osmosis stage is not inferior to that of mains water. The membrane in the first stage is ultrafiltration, capable of removing bacteria and viruses, and this is more so in the reverse osmosis stage. Additionally the water is dosed by means of chlorination in the same

controlled manner as in mains water. There is real time monitoring at all stages and if there is a malfunction the system is automatically stopped.

ET: Is the system specifically for hotels?MC: There are many situations where the system can be used. For instance a high rise residential building is built in a location where the public sewer system is insufficient to cater for the amount of sewage, or a tourist complex in an exotic place where the water supply cannot cope with the demands of the complex.

ET: What experience is there on the system?MC: I have installed the system on a prototype with a consumption of 15 cubic meters a day for over a year and I also have a contract with a hotel where I installed and own the system, and sell the treated water to the hotel at favourable prices. The risk is on me but I am confident that the technology is right and will achieve the expected results.

ET: Is the system complex to operate, and does it require specialized operators?MC: The system is provided with the right amount of automation and instrumentation for monitoring the performance, but needs regular inspections especially in the initial stages.

ET: Does the tariff system in Malta encourage private sewage treatment?


Incoming sewage; activated sludge; 2nd class water (before disinfection and colour-removal); potable-grade water


MC: The Water Service Corporation does not charge for its sewage and this is against EU standards which applies the Polluter Pays principle. Water quality is also problematic and more of the water is coming from reverse osmosis. There is a need to address these problems.

HOTER was one of three finalists in the prestigious Euro 250,000-prize CNBC/Allianz Good Entrepreneur 2009 competition that sought the Best Green Business Idea in Europe, for which there were 250 entries. CNBC produced 4 episodes of 45 minutes each which were broadcast worldwide in November/December 2009 (with repetitions in 2010). Although HOTER did not win the big prize, it was voted as the most popular project among the 250 entries.

HOTER also won the national prize in the Energy Globe awards 2009, which is recognised as the foremost prize for sustainable initiatives in the world.

In 2012 Marco Cremona was nominated and shortlisted for the Stockholm Water Prize 2012, which is recognised as the Nobel Prize equivalent in the water sector. Of course, HOTER was a contributing factor in this world-class shortlist. ET


Ing. John PaceEditor,Engineering Today

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“Investigating the Potential of Aesthetic Laser Marking in the Toy Manufacturing Industry”.

Painting without paintby Luke Said

This article is about a final year project from the Department of Industrial and Manufacturing Engineering by Mr. Luke Said, supervised by Ing. Pierre Vella and Ing. Emmanuel Francalanza.

Environmental friendliness and cost effectiveness are two critical characteristics to take into consideration when selecting a manufacturing process. Laser marking possesses both. Aesthetic laser marking, is a geometrically flexible process used to achieve aesthetic features. This process can be automated using special purpose software which governs the design of the features as well as processing parameters of this process. Playmobil Malta Ltd was interested in the feasibility of this process in order to replace costly conventional pad printing. The latter uses ink whereas laser marking requires no form of material deposition. Hence the only cost involved is the cost to operate the laser.

Playmobil Malta Ltd had carried out initial experimentation with laser marking on two existing plastic products which were the ‘Baby Crocodile’ and the ‘Baby Koala’. These two are mass produced using pad printing; and successfully replicating them using laser marking would be very beneficial. These two products can be seen in Figure 1.

Ethylene Vinyl Acetate (EVA) is the bulk polymer used in both cases, and the both have the same grey ‘masterbatch’. The latter is the colorant of an injection moulded part. The crocodile has the inclusion of a foaming agent, which modifies the mechanical properties of the product. The aim of this process applied to these products, is to achieve a black mark on a grey background. As can be seen clearly in Figure 1, only a darker shade of grey was achieved. Hence further optimization was required in order to make the process feasible. The effects of using a different material were also proposed. The first objective was therefore the optimization of the current marking process, by identifying the most effective process parameters. The second objective was to use the knowledge generated in order to investigate the possibility of using a different material.

In order to meet the aforementioned objectives, an understanding of the laser marking process was required. Laser marking simply involves a material reacting to a laser beam. The process is governed by the absorption mechanisms involved in this process; and illustration of so can be seen in Figure 2.

Figure 1- Baby Crocodile and Baby Koala Figure 2- Laser Marking Principle


The type of reaction that takes place depends on the wavelength of the laser, coupled with the absorption mechanisms of the surface of the material being marked. Two types of wavelengths are used for the marking of plastics; infrared and ultraviolet. The former causes heat induced reactions whereas the latter causes photochemical reactions. An example of a heat induced reaction is carburizing of the material surface. This leads to a darker marking due to the ‘burning’ of the surface. Photochemical reactions involve a molecule absorbing an incident photon and changing chemically. These reactions require the highest photonic energy. An example of a photochemical reaction is the photochemical ‘degradation’ of Titanium Dioxide, which upon exposure to ultraviolet rays turns from white to grey.

A Design of Experiments (DOE) approach was employed in this project. This is the systematic design and carrying out of experiments in order to make appropriate conclusions about the results achieved. The phases of this approach involve Planning Experiments, Designing Experiments,

Conducting Experiments, Analysing Results and Conclusions. The first thing that was considered was the laser in use at Playmobil Malta Ltd. This is a 3 Watt, 3555nm wavelength laser. Hence the marking process is photochemical. For the optimization of the baby koala and baby crocodile EVA and a grey ‘masterbatch’ had to be considered; as well as the inclusion of the foaming agent. The majority of products made by pad printing in this company are made of Acrylonitrile Butadiene Styrene (ABS). Hence this was the second material to be considered. White and Natural ABS were considered as well as the addition of a mark enhancing additive for each. The design of the laser marking was achieved using special purpose software.

A critical question that was asked at this stage was: “What are we going to measure in order to assess the quality achieved by the material selection and processing parameters used?” The answer was colour. The principles of colourimetry were used in order to measure the colour achieved. This is expressed as the ‘distance’ of an achieved colour from a reference colour.

Painting without paint (cont.)

Figure 3 - Best Results Achieved


The reference colour used for the EVA products was theoretical pure black whereas for the ABS products, the most aesthetically pleasing result was used as a reference for the Natural and the ‘moss grey’ RAL colour was used for the White. The design of the mark was simply a 20mm circle as was marked on a colour tag shape; which is the flattest available part made by the company. Figure 3 shows the best results achieved. From left to right the materials in Figure 3 are: Grey EVA with (top) and without (bottom) the foaming agent, White ABS with (top) and without (bottom) the mark enhancing additive and Natural ABS with (top) and without (bottom) the mark enhancing additive.

The foaming agent did not affect the mark for EVA. The mark enhancing additive gave slightly better contrast for White ABS, and gave clearly superior results for Natural ABS. The most effective process parameter was found to be the Pulse Frequency (Pulses/second). For a fixed laser power, a lower number of pulses yield a higher pulse power, and hence more photons are available to cause photochemical reactions. The number of photons per pulse can be found using equation 1:

Equation 1

Where P is the laser power, λ is the wavelength of the laser beam, F is the pulse frequency, h is Planck’s constant, and c is the speed of light.

From the results achieved it is evident that the colour achieved is based on the material and laser selection. The contrast achieved is greatly dependent on the processing parameters; the most effective of which is the Pulse Frequency. Further optimization can be achieved as part of future work. Also a different laser and more materials could be tested. Playmobil Malta did not find the current state of aesthetic laser marking feasible for mass production. However regardless of this, this manufacturing process has shown to have great potential. ET

Luke SaidGraduated in 2011 Currently reading for a Masters in Mechanical Engineering,Department of Industrial and Manufacturing Engineering,University of Malta

Painting without paint (cont.)

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