Aquatics Centre,London 2012 Olympic and Paralympics Games

The Aquatics Centre is a centrepiece of the London 2012 Olympic and Paralympic Games. Already now before the opening of the Games it is regarded as an iconic legacy building. The building comprises a 50 m competition pool and 25 m dive pool under the wave‐form roof of the main pool hall. A 50 m training pool is situated beneath the Olympic Park entrance plaza structure which is built integrally with the rest of the building. The engineering strategy has been developed around two basic configurations; the Games mode and Legacy Mode. In the Games mode the facility has a maximum gross spectator capacity of 17 500 for use for the London 2012 Games as well as housing facilities for the running of these events. In that mode temporary stands to the east and west of the competition and diving pools will seat approx. 15 000 spectators. In the legacy mode the building temporary seating will be dismantled and the building will be a permanent pool facility for the local community as well as national and international swimming events beyond the Games. Each pool tank is provided with a combination of floating floors and movable sub‐division boom bulkheads to allow multiple legacy and community use. Schwimm‐Arena der Olympischen und der Paralympischen Spiele London 2012 Die Schwimm‐Arena ist eines der Hauptgebäude der Olympischen wie auch der Paralympischen Spiele in London 2012. Schon vor Beginn der Spiele wurde es zu einer baulichen Ikone. Unter einem wellenförmigen Dach befinden sich ein 50‐m‐Schwimmbecken sowie ein 25‐m‐Becken mit Sprungtürmen. Das 50‐m‐Aufwärmbecken liegt unter einem der Eingänge zum Olympia Park, der so genannten Plaza. Die ingenieurtechnischen Planungen erfolgten gemäß den unterschiedlichen Anforderungen der “Games Mode” und der “Legacy Mode” nach den Spielen. Während der Spiele bestehen Tribünenplätze für 17 500 Zuschauer sowie alle damit verbundenen sonstigen räumlichen Anforderungen. Die westlich und östlich der Becken gelegenen temporären Tribünen nehmen 15 000 Zuschauer auf. Für die “Legacy Mode” werden diese wieder abgebaut und die Schwimmhalle wird dann von der breiten Öffentlichkeit und für nationale wie internationale Schwimmwettbewerben genutzt. Alle Schwimmbecken verfügen über höhenverstellbare Böden und Unterteilungen.     

Polarised light stress analysis and laser scatter imaging for non-contact inspection of heat seals in food trays

This paper introduces novel non-contact methods for detecting faults in heat seals of food packages. Two alternative imaging technologies are investigated; laser scatter imaging and polarised light stress images. After segmenting the seal area from the rest of the respective image, a classifier is trained to detect faults in different regions of the seal area using features extracted from the pixels in the respective region. A very large set of candidate features, based on statistical information relating to the colour and texture of each region, is first extracted. Then an adaptive boosting algorithm (AdaBoost) is used to automatically select the best features for discriminating faults from non-faults. With this approach, different features can be selected and optimised for the different imaging methods. In experiments we compare the performance of classifiers trained using features extracted from laser scatter images only, polarised light stress images only, and a combination of both image types. The results show that the polarised light and laser scatter classifiers achieved accuracies of 96% and 90%, respectively, while the combination of both sensors achieved an accuracy of 95%. These figures suggest that both systems have potential for commercial development.     

Optimization of Pb-Free Solder Joint Reliability from a Metallurgical Perspective

To obtain the desired performance of Pb-free packages in mechanical tests, while the solder composition should be carefully selected, the influence of metals dissolved from the soldering pad or under bump metallization (UBM) should also be taken into account. Dissolved metals such as Cu can alter the intermetallic compound (IMC) formation, not only at the local interface but also on the other side of the joint. The high rate of interfacial cracking of Sn-Ag-Cu solder joints on Ni/Au-plated pads is attributed to the high stiffness of the solder and the dual IMC structure of (Cu,Ni)₆Sn₅ on Ni₃Sn₄ at the interface. Approaches to avoid this dual IMC structure at the interface are discussed. A rule for selecting the solder alloy composition and the pad surface materials on both sides of the joints is proposed for ball grid array (BGA) packages.     

Comparison of the Impact of γ-Oryzanol and Corn Steryl Ferulates on the Polymerization of Soybean Oil During Frying

Corn steryl ferulates (CSF), oryzanol, a combination of equal amounts of CSF and oryzanol, and ferulic acid were added to refined, bleached, deodorized, soybean oil at a concentration of 8.1–8.4 μmol/g oil, which corresponded to 0.5% (w/w) for the steryl ferulates. The rate of polymerized triacylglycerol (PTAG) formation was determined in three replicate, two-day frying experiments using a miniature frying protocol with potato cubes. Oryzanol and ferulic acid slightly inhibited PTAG formation on the first day of frying. However, the two treatments were not significantly different from the SBO control on the second day of frying. CSF and the combination of CSF and oryzanol significantly inhibited PTAG formation on both days of frying, but the combination was slightly more effective on the second day of frying. Tocopherol degradation in SBO with added oryzanol or ferulic acid proceeded more rapidly compared to the control. However, CSF and the combination of CSF and oryzanol appeared to protect tocopherols from degradation. In addition, CSF was more stable to frying compared to oryzanol, but when CSF and oryzanol were combined, CSF protected oryzanol from degradation.     

The tensile behavior of off‐axis loaded plant fiber composites: An insight on the nonlinear stress–strain response

Composites in load‐bearing applications are often exposed to off‐axis loads. For plant fiber composites (PFCs) to be seriously and readily considered in structural applications, knowledge and reliable prediction of their response to off‐axis loads is critical. This article (i) characterizes the stress–strain response, (ii) investigates the tensile properties, and (iii) analyses the fracture modes, of unidirectional flax‐polyester composites subjected to off‐axis tensile loading. A key finding of this study is that due to the nonlinear stress–strain response of PFCs, the apparent stiffness of the composite reduces by ∼30% in the strain range of 0.05 to 0.25%. In addition, through cyclic tests on the composites, the elastic strain limit is found to be only ∼0.15%. This has major implications on the strain range to be used for the determination of the composite elastic Young's modulus. Consequently, it is proposed that the tensile modulus for PFCs should be measured in the strain range of 0.025 to 0.100%. Through comparison with experimental data, conventional composite micromechanical models are found to be adequate in quantitatively describing the tensile behavior of off‐axis loaded PFCs. The application of such models has also enabled the determination of, otherwise difficult to measure, material properties, such as fiber shear and transverse modulus. Off‐axis loaded PFCs fail by three distinct fracture modes in three different off‐axis ranges; each fracture mode produces a unique fracture surface. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers     

Simultaneous determination of fragmentation and coalescence rates during pilot-scale high-pressure homogenization

The emulsification process is primarily determined by the rate of fragmentation and coalescence of emulsion drops. However, there is presently no fast, reliable method for measuring these rates for pilot and production scale high pressure homogenizers.     

Balkon zum Meer – Die Seebrücke in Saßnitz

Im Jahr 2007 wurde in Saßnitz der 250 m lange “Balkon zum Meer” fertiggestellt. Die Besonderheit dieser Fußgängerbrücke ist, dass sie über eine freie Spannweite von 120 m als einseitig aufgehängte, im Grundriss gekrümmte Hängebrücke mit exzentrisch angeschlossenen Hängerseilen ausgebildet ist. Die Brücke, die eine seit langem benötigte Verbindung zwischen der Stadt Saßnitz und dem 25 m tiefer liegenden Stadthafen herstellt, wurde 2010 mit dem Deutschen Brückenbaupreis ausgezeichnet. Der vorliegende Artikel beschreibt den Entwurf, die konstruktive Durchbildung und die Bauausführung dieser einzigartigen Konstruktion. alcony overlooking the sea – The Sea Bridge Saßnitz, Germany. In July 2007, a 250 m long suspension bridge for pedestrians was inaugurated in the city of Saßnitz on Rügen Island in the German part of the Baltic Sea. The curved part of the deck of 120 m length is supported by cables on one side only. The bridge, one of the longest of its kind, is part of an urban renewal project. It reconnects Saßnitz Harbour to the city, being separated from each other during the cold war. The most interesting feature of this bridge is the cantilevering support girders that protrude from the deck to connect to the hangers so that their axes aim towards the centre of gravity of the pertinent deck section. This structural solution allows for one‐sided hanger supports without causing bending or torsion in the curved girder due to distributed dead load or live loads. The paper describes the structural concept of the Saßnitz Bridge. It also elaborates on structural design and erection issues.