Science & Technology

September 5th 2006

Forgery concerns the alteration of details on licences, ID cards, passports and other documents which can lead to large financial losses, identity theft, etc. – a growing area!

Re-use of genuine containers, e.g. alcoholic drinks bottles and packaging for cameras, software, etc., which may then contain counterfeit shoddy products.

Tampering/grazing – removing contents partially and refilling or malicious contamination (medicines and baby foods can be cited). Fatal consequences have occurred.

October 3rd 2006

Du Pont USA in 1928 led the world in synthetic fibre research and nylon stockings were on sale in the USA in 1940. Developments in England by Calico Printers Association Ltd. led to ICI polyester fibre Terylene in the late 1940s. Nylon, polyester and acrylic fibres account for 99% of all synthetic fibres, with huge annual tonnage outputs in Europe, USA, Japan and China. Routes to the chemical syntheses and means of producing the range of synthetic fibres we now enjoy were detailed.

Comparisons of properties were made for different applications ranging from textiles, food and drinks packaging to engineering and electronic applications. Polyester (PET) accounts for the majority of synthetic fibre usage and is frequently used in combination with natural fibres such as cotton for fabrics.

The importance of recycling plastic products was also highlighted in this excellent presentation for which Norman has prepared a detailed, illustrated review.

November 7th 2006

In a well balanced and challenging presentation Stan Skinner pointed out at the November meeting that our current dependence on the still growing use of fossil fuels could not be long sustained. Accepting that global warming (a major contributor being carbon dioxide) must be slowed and eventually limited, Stan reviewed the problems illustrated by the current world dependence on fossil fuels and, excluding nuclear generation, concentrated on four areas which are truly renewable. Solar energy was and is the source of crucial energy for life on earth. Two ways of using solar radiation were detailed. The first, which includes building design, is in the direct collection of sunlight by solar panels for heating. The second is the generation of electricity by using photovoltaic devices. The problems are the availability of good sunlight and its intermittent nature. Also very large surface areas for collection are needed.

Wind energy, also intermittent, can create aesthetic and ecological resistance as large and numerous wind turbine farms widely distributed are required to generate even a low percentage contribution to other than local needs.

Wave energy methods include tapered channel collection and wave collection reservoir systems. The potential in Britain is high but huge expensive schemes are required to generate power consistently in adverse environments. Tidal power, used in Brittany, seems attractive and could be employed in some British areas such as the Severn, Mersey and Humber estuaries, again with environmental design and investment problems. Significant percentages of power needs could be produced, at least locally.

Biomass (plant and animal materials and waste) also produce carbon dioxide but some can be used to produce fuels such as alcohols. Unfortunately biomass usage often involves destruction of the environment if removal exceeds the rate of replanting of trees, etc. Fast growing crops such as sugar can have possibilities but much land usage, not then available for food, is required.

Stan concluded that compromises in lifestyles and international co-operation would be essential for the improvements needed to take place.

November 23rd 2006

After an introduction, Keely Gallagher, Veolia’s Communications Co-ordinator, showed a detailed video of the development and operation of the unit. Many questions followed which were most ably answered.

Project Integra relies on householders separating waste at home. The mixed recyclables at Alton MRF are sorted into aluminium and steel cans, paper, board, cardboard and plastic bottles for recycling. Colour detector near infra-red instrumentation allows the selection of dyed papers and printed items.

A tour of the building revealed impressive features of scale, cleanliness, organisation and control of waste disposal. 90,000 tonnes of waste can be processed p.a. at the Chineham ERF alone. Material not selected for further reprocessing or recycling is fed into an incinerator, run at 1000ºC, to ensure complete combustion. The heat generated through a tubular boiler generates steam which drives an electric generator. Continuous operation supplies 8MW of electricity to the National Grid (enough for 8000 houses). The ash residues are filtered to remove metals and fines so that only minute combustion products apart from steam, which has been scrubbed, emerges from the 45m high chimney stack.

The plant is run by 35 people in shifts from an computerised control room where all operations, especially emissions, are monitored. The recovery of many materials, including glass, is impressive, and the group felt that this facility indicates a vital approach for future environmentally effective waste disposal.

Our thanks are due to Keely and Veolia Environmental Services for their courtesy and efficiency during the planned visit.

January 2nd 2007

As an introduction to 2007 Ralph reminded the group at the January meeting of the ever increasing threat to security documents of all types as villains adopt new technology.

Currency, bonds, certificates, licences and particularly documents such as passports, ID and financial cards suffer from not only counterfeiting and forgery but in addition personal identity attacks and also financial loss. Earlier threats of hand and photographic plate preparation have been expanded by the advent of scanners/copiers, laser, inkjet and thermal printing.

Members study Ralph's Exhibits.

Three levels of detection to classify security features used in documents such as banknotes were defined: Level 1 – publicly visible and recognisable Level 2 – assisted reading, e.g. UV lamps, filters, magnets Level 3 – machine readable features; forensic standard Security features typically used in top level unlaminated documents such as banknotes, bonds and travellers cheques include watermarked security papers with threads, intaglio portraits and fine lithographic printing. Passports and ID cards contain rainbow and luminescent print features, sensitive papers, photographic and other personal details, codes, etc., all of which are secured under tough laminate covers often with holographic interlayers.

Financial cards use embossed plastic carrying magnetic stripes, holograms, microchips and sensitive signature panels as well as security print. Descriptions of intaglio, offset lithographic electronic letterpress printing and numbering were illustrated.

For those interested a visit to the Bank of England and Bank of Canada websites would provide excellent details of existing and proposed changes to banknotes.

A later lecture is proposed to amplify printing developments over the centuries.

February 6th 2007

The function of blood is to carry all that the body cells need to perform well and to remove waste materials. Nutrients include sugar, fat, protein, water, amino acids, oxygen, etc. Waste matter includes carbon dioxide, nitrogenous and other materials (processed and removed by lungs and kidneys). The structures of blood cells (red to carry oxygen, white to resist infections) and platelets (which assist clotting of wounds) were detailed. More than 30 blood groups, their frequency and aspect of safe transfusions were explained. The value of healthy hearts and circulation systems were noted as were serious conditions such as leukaemia and anaemia. Pierce’s excellent presentation on this difficult topic was accompanied by a detailed hand-out with explanatory graphics and tables.

March 6th 2007

Noting the importance of understanding Boyle’s Law and how pressure on a submerged body increases rapidly with depth, Mike introduced the topic of mixed gas diving. Divers must breath gas at the ambient pressure because of pressure on the chest which restricts breathing. Narcotic effects can be produced using air because at depths such as 20 to 40m the dissolution of nitrogen in the blood can have serious results. Decompression illness, i.e. bends, is caused if ascents from depths are too rapid, allowing nitrogen bubbles to be formed in the bloodstream. This can also happen with dives in rapid succession.

Sports diving employs mixtures of oxygen and nitrogen, depending on the ratio needed for different depths. These Nitrox mixtures must be carefully selected as excessive oxygen can also cause sudden dramatic narcotic effects, i.e. hyperoxia. An elegant dive computer attached to the diver’s wrist helps to indicate optimum dive conditions.

For deep commercial diving Trimix, made of three gases, is used. These mainly consist of oxygen, nitrogen and helium in different ratios selected for depths down to 130m.

Mike emphasised the importance of good dive planning in teams, using technical diving equipment and described the use of various gas cylinders providing gas mixtures. The use of Re-breathers, which remove carbon dioxide, has allowed longer dives with less bulky equipment providing automatic gas mixture control.

The range of questions and illustrations of practical diving showed the group’s active interest in Mike’s talk and his experiences. Mike did express admiration for Winchester Cathedral’s “Bill the diver” and his under water work in the restoration of the building’s foundation. (Homework – look this up!)

April 3rd 2007

Digital Television Switchover

The presentation by Norman Long at our April meeting was timely in view of TV changes which will affect us all.

Using two television sets, Norman started in a novel way by showing clips from old black and white programmes such as “Muffin the Mule” and others more progressively modern which gave nostalgic flash-backs to our group members.

This reminded us of the recent 70th anniversary of TV broadcasting and the rapid developments which have followed since the earliest innovations. John Logie Baird’s invention of a mechanical system based on Nipkow’s earlier work during the 1920s was highlighted.

The BBC in 1929 broadcast with Baird’s 30 line system, replaced later by Marconi EMI CRT developments. Huge steps in growth occurred in 1952 with the coronation of HM The Queen when a TV audience of 20 million was recorded. Rapid further developments followed, e.g. in colour television in 1969 following the 1968 Mexico Olympics, the Apollo landings, etc.

The digital TV developments were driven by military and space programmes which allowed huge advances in data compression techniques. The timescales and regional UK digital TV changes now ongoing were noted, whilst the advantages and disadvantages were also stated. The requirements for changes depend on individual choices as to the range of programmes required and whether by terrestrial or satellite means. Digital boxes and personal video recorders will be available but Norman gave some sound recommendations such as checking digital signal reception, receivers or boosters needed. A demonstration given on setting up a “digi-box”, excellent graphics and a detailed report accompanied his expert presentation

May 1st 2007

The Elements – Nature’s Lego

As Pierce informed us at our May meeting, the ancient Greek school of Leucippus and Democritus taught that all things were composed of moving spherical atoms. In a similar era, around the 4th century BC Aristotle taught that all matter was composed of air, earth, fire and water as the four basic elements. Right through the age of alchemy (transmutation of elements) until around 1700 AD, when the true science of chemistry dawned, these ideas wrongly held sway.

The structure of the modern “Periodic Table of Elements”, which organises the c.90 natural elements now known, followed brilliant work by John Dalton (1766-1844), Alexandre Chancourtois (1820-86), Dmitri Mendeleer (1834-1907) and Henry Moseley (1887-1913) who showed that the elements should be arranged in order of atomic number.

The concepts of atomic structure in terms of protons (the number defining a particular element), the neutron (which with the proton comprise the atomic weight of an atom) and the very light electrons were explained. The chemical properties of atoms are governed by the electronic shell structure and the availability of outermost electrons to combine with other atoms to form compounds. The various types of bonding in matter, such as covalent and ionic, were noted with examples in sketches and physical items, e.g. salt, copper and mercury.

Pierce then showed the limitless number of chemical compounds which exist from around 90 elements which was in significant contrast to the very large number of Lego structures which can be made from the different constructional bricks and one push-fit bond.

Finally, nature’s elemental surprises were illustrated, and the eight page hand-out is an excellent guide for scientists of all ages.

June 5th 2007

Construction of the Marks & Spencer HQ

The unusual design and construction of this attractive and complex building at 1/2 Waterside, Paddington Basin was the topic for our June meeting. Alistair Craig, employed as Chief Engineer for Carillion plc, was involved in resolving engineering and material problems which arose in the course of construction. He gave a very systematic, illustrated account of this development.

Close to Paddington Station and running alongside the Grand Union Canal, the design by Lord Rogers posed a range of challenging problems. The building is 105 x 50m ground area and 45m high. Provisions included 12 storeys to give 25,000 square metres office space.

Barriers against ground water from the canal were constructed to allow 10m depth of basement excavation and in July 2001 the deep pilings into the London clay commenced. Pre-stressed and post-stressed reinforced concrete components were used with large imported structural steel elements.

Various stages for the different floors followed, and glass and metal curtain wall cladding were applied. Fine finish concrete was used for maximum aesthetic effect. Very tight tolerances were maintained throughout and computer models indications were monitored by direct observation of any structural movements.

The completed building is a triangular, sharp edged, fully operational facility and a credit to the designers and construction engineers involved.

July 3rd 2007

Railway Accident Investigations

At our July meeting Inspector Simon Kay outlined the role of the Railway Accident Investigation Branch (RAIB) which was established in October 2005. RAIB inspection teams have a leading role in all cases where no evidence of criminality has been reported by the police, and act entirely independently. The RAIB covers national railway networks in Great Britain and Northern Ireland, the Channel Tunnel (in co-operation with France), London Underground, Glasgow and other Metro systems, tramways, heritage railways, etc.

The purpose of the highly trained, technically balanced RAIB teams is to improve railway safety by investigating and reporting in detail causes of railway accidents and incidents and concerns for safety and the improvements required. The operational systems for rapid response to attend accident sites, the sophisticated equipment vehicles and the investigational facilities were noted. Simon displayed the impressive contents of his inspector’s “instant” kitbag.

He emphasised the importance of collecting, recording and preserving evidence, which could range from a steel nut to a whole train (which had to be moved to another site). Some pictures of incidents involving derailed trains, trams, a collapsed tunnel and a train trapped in a mudslide were shown. In all cases the rapid reopening of the railway system was a priority, to avoid unnecessary cost to the operators.

The reports of all investigations and those in hand are published, with the aim of giving reassurance to the public and to increase awareness. The RAIB website gives excellent coverage, with graphics, of all the operating rules and investigational reports including the recent Grayrigg, Cumbria, derailment in February 2007. The website is www.raib.gov.uk.

Simon dealt well with many questions within the limits of what he was able to divulge. We are grateful to him and the RAIB for his clear exposition.