AdamSmith

http://img.memecdn.com/ein-currency-to-rule-ze-entire-world_o_3627965.jpg

Delayed climax is not my forte.

http://netz10.de/wp-content/uploads/2012/05/zitronenpresse_small.jpg

http://3.bp.blogspot.com/-fY66JMtKwNs/Tuo0fAhy62I/AAAAAAAAlpI/FqJA_FnhJfA/s1600/humor-angela-merkel.jpg

http://www.bildersuche.org/kunst/daily-mona-lisa-bilder/mona-lisa-angela-merkel-gr.jpg

For tomorrow... http://www.pattayajungle.com/images/BHPC_joke.jpg http://eurokulture.missouri.edu/wp-content/uploads/2012/09/terminator_merkel_web-300x204.jpg http://randomoverload.org/wp-content/uploads/2011/11/436efa93ld-conflict.jpg http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2012/5/31/1338460545901/German-Chancellor-Merkel--008.jpg

http://i-sight.com/wp-content/uploads/2011/06/Smoke-Detector1.jpg

Friday on Wednesday... (This was a real ad!) http://usercontent2.hubimg.com/1491767_f520.jpg

Put it in the bank for next Friday...

Come on, Friday...!

Well, it feels like Friday...

Can't put anything past an Ozzie. In fact my longtime business partner in Cambridge grew up in Melbourne and got his engineering degree from "your" MIT.

My crack was particular to that portion of the Commonwealth of Massachusetts consisting of the Boston metropolitan area, and especially the... People's Republic of Cambridge An independent state just north of Boston, with two universities and one way of waging war: writing nasty notes and putting them on people's windshields. Has enough organic grocery stores, indie bookshops, and other college-town fripperies to satisfy an army of Sartre-reading undergrads. Newbie: Why do they call this place the People's Republic of Cambridge? Native: Because more people voted for Nader than Bush in 2000. Cambridgeite 1: You wanna go down to Bread & Circus and pick up some pine nuts and kale? Cambridgeite 2: But that's really out of my way, I was planning to head down to Harvard Books. If only we had public transportation we could solve this problem. Cambridgeite 1: What do you think this is, New York? I am so sticking a note on your car for your thought crimes. http://www.urbandictionary.com/define.php?term=People's+Republic+of+Cambridge P.S. I (AS) should add that the proper term for a denizen thereof is of course 'Cantabridgian.' P.P.S. Disclosure--I was one myself for 28 years. Does it show?

Demonstrating my point.

In Cambridge, MA, Whole Foods definitely has a hiring preference for neurotic nut cases. Of course to do otherwise, they would have to recruit from the western half of the state.

And in honor of the just-completed US Open...

Put this in the bank for next Friday...

A&P -- The Great Atlantic & Pathetic Tea Co.

Although to be fair, Whole Foods deserves credit and thanks for prodding a number of the mainstream grocery chains into upping their game in response.

...cont. For its part, Harland and Wolff, after its long silence, now rejects the charge. “There was nothing wrong with the materials,” Joris Minne, a company spokesman, said last week. Mr. Minne noted that one of the sister ships, the Olympic, sailed without incident for 24 years, until retirement. (The Britannic sank in 1916 after hitting a mine.) David Livingstone, a former Harland and Wolff official, called the book’s main points misleading. Mr. Livingstone said big shipyards often had to scramble. On a recent job, he noted, Harland and Wolff had to look to Romania to find welders. Mr. Livingstone also called the slag evidence painfully circumstantial, saying no real proof linked the hull opening to bad rivets. “It’s only waffle,” he said of the team’s arguments. But a naval historian praised the book as solving a mystery that has baffled investigators for nearly a century. “It’s fascinating,” said Tim Trower, who reviews books for the Titanic Historical Society, a private group in Indian Orchard, Mass. “This puts in the final nail in the arguments and explains why the incident was so dramatically bad.” The Titanic had every conceivable luxury: cafes, squash courts, a swimming pool, Turkish baths, a barbershop and three libraries. Its owners also bragged about its safety. In a brochure, the White Star Line described the ship as “designed to be unsinkable.” On her inaugural voyage, on the night of April 14, 1912, the ship hit the iceberg around 11:40 p.m. and sank in a little more than two and a half hours. Most everyone assumed the iceberg had torn a huge gash in the starboard hull. The discovery in 1985 of the Titanic wreck began many new inquiries. In 1996, an expedition found, beneath obscuring mud, not a large gash but six narrow slits where bow plates appeared to have parted. Naval experts suspected that rivets had popped along the seams, letting seawater rush in under high pressure. A specialist in metal fracture, Dr. Foecke got involved in 1997, analyzing two salvaged rivets. He was astonished to find about three times more slag than occurs in modern wrought iron. In early 1998, he and a team of marine forensic experts announced their rivet findings, calling them tentative. Dr. Foecke, in addition to working at the National Institute of Standards and Technology, also taught and lectured part time at Johns Hopkins. There he met Dr. McCarty, who got hooked on the riddle, as did her thesis adviser. The team acquired rivets from salvors who pulled up hundreds of artifacts from the sunken liner. The scientists also collected old iron of the era — including some from the Brooklyn Bridge — to make comparisons. The new work seemed only to bolster the bad-rivet theory. In 2003, after graduating from Johns Hopkins, Dr. McCarty traveled to England and located the Harland and Wolff archives at the Public Record Office of Northern Ireland, in Belfast. She also explored the archives of the British Board of Trade, which regulated shipping and set material standards, and of Lloyd’s of London, which set shipbuilding standards. And she worked at Oxford University and obtained access to its libraries. What emerged was a picture of a company stretched to the limit as it struggled to build the world’s three biggest ships simultaneously. Dr. McCarty also found evidence of complacency. For instance, the Board of Trade gave up testing iron for shipbuilding in 1901 because it saw iron metallurgy as a mature field, unlike the burgeoning world of steel. Dr. McCarty said she enjoyed telling middle and high school students about the decade of rivet forensics, as well as the revelations from the British archives. “They get really excited,” she said. “That’s why I love the story. People see it and get mesmerized.” http://www.nytimes.com/2008/04/15/science/15titanic.html?pagewanted=all&_r=0

P.S. Fasteners in manufactured products never get the glory until they are the cause of failure. For example the Titanic's steel hull plates were calculated to have a certain strength and stiffness, but the iron rivets holding them together became brittle and fracture-prone much sooner in the supercooled water of the north Atlantic. In Weak Rivets, a Possible Key to Titanic’s Doom http://graphics8.nytimes.com/images/2008/04/14/science/14titanic-600.jpg Smithsonian Titanic, left, and Olympic sit next to one another in a double gantry while under construction. More Photos > By WILLIAM J. BROAD Published: April 15, 2008 The New York Times Researchers have discovered that the builder of the Titanic struggled for years to obtain enough good rivets and riveters and ultimately settled on faulty materials that doomed the ship, which sank 96 years ago Tuesday. Multimedia http://graphics8.nytimes.com/images/2008/04/14/science/041308Titanic-B.JPG Slide Show The Weak Link of the Titanic http://graphics8.nytimes.com/images/2008/04/15/science/15titanic_graph.190.gif Not So Unsinkable The builder’s own archives, two scientists say, harbor evidence of a deadly mix of low quality rivets and lofty ambition as the builder labored to construct the three biggest ships in the world at once — the Titanic and two sisters, the Olympic and the Britannic. For a decade, the scientists have argued that the storied liner went down fast after hitting an iceberg because the ship’s builder used substandard rivets that popped their heads and let tons of icy seawater rush in. More than 1,500 people died. When the safety of the rivets was first questioned 10 years ago, the builder ignored the accusation and said it did not have an archivist who could address the issue. Now, historians say new evidence uncovered in the archive of the builder, Harland and Wolff, in Belfast, Northern Ireland, settles the argument and finally solves the riddle of one of the most famous sinkings of all time. The company says the findings are deeply flawed. Each of the great ships under construction required three million rivets that acted like glue to hold everything together. In a new book, the scientists say the shortages peaked during the Titanic’s construction. “The board was in crisis mode,” one of the authors, Jennifer Hooper McCarty, who studied the archives, said in an interview. “It was constant stress. Every meeting it was, ‘There’s problems with the rivets and we need to hire more people.’ ” Apart from the archives, the team gleaned clues from 48 rivets recovered from the hulk of the Titanic, modern tests and computer simulations. They also compared metal from the Titanic with other metals from the same era, and looked at documentation about what engineers and shipbuilders of that era considered state of the art. The scientists say the troubles began when its ambitious building plans forced Harland and Wolff to reach beyond its usual suppliers of rivet iron and include smaller forges, as disclosed in company and British government papers. Small forges tended to have less skill and experience. Adding to the problem, in buying iron for the Titanic’s rivets, the company ordered No. 3 bar, known as “best” — not No. 4, known as “best-best,” the scientists found. Shipbuilders of the day typically used No. 4 iron for anchors, chains and rivets, they discovered. So the liner, whose name was meant to be synonymous with opulence, in at least one instance relied on cheaper materials. Many of the rivets studied by the scientists — recovered from the Titanic’s resting place two miles down in the North Atlantic by divers over two decades — were found to be riddled with high concentrations of slag. A glassy residue of smelting, slag can make rivets brittle and prone to fracture. “Some material the company bought was not rivet quality,” said the other author of the book, Timothy Foecke of the National Institute of Standards and Technology, a federal agency in Gaithersburg, Md. The company also faced shortages of skilled riveters, the archives showed. Dr. McCarty said that for a half year, from late 1911 to April 1912, when the Titanic set sail, the company’s board discussed the problem at every meeting. For instance, on Oct. 28, 1911, Lord William Pirrie, the company’s chairman, expressed concern over the lack of riveters and called for new hiring efforts. In their research, the scientists, who are metallurgists, found that good riveting took great skill. The iron had to be heated to a precise cherry red color and beaten by the right combination of hammer blows. Mediocre work could hide problems. “Hand riveting was tricky,” said Dr. McCarty, whose doctoral thesis at Johns Hopkins University analyzed the Titanic’s rivets. Steel beckoned as a solution. Shipbuilders of the day were moving from iron to steel rivets, which were stronger. And machines could install them, improving workmanship. The rival Cunard line, the scientists found, had switched to steel rivets years before, using them, for instance, throughout the Lusitania. The scientists discovered that Harland and Wolff also used steel rivets — but only on the Titanic’s central hull, where stresses were expected to be greatest. Iron rivets were chosen for the stern and bow. And the bow, as fate would have it, is where the iceberg struck. Studies of the wreck show that six seams opened up in the ship’s bow plates. And the damage, Dr. Foecke noted, “ends close to where the rivets transition from iron to steel.” The scientists argue that better rivets would have probably kept the Titanic afloat long enough for rescuers to arrive before the icy plunge, saving hundreds of lives. The researchers make their case, and detail their archive findings, in “What Really Sank the Titanic” (Citadel Press). Reactions run from anger to admiration. James Alexander Carlisle, whose grandfather was a Titanic riveter, has bluntly denounced the rivet theory on his Web site. “No way!” Mr. Carlisle writes. Cont...

...continued... From the graph, trends can be identified that provide early insight into the behavior of the materials, which aids in making design decisions. For example, the paint layer is characterized by higher values of CTE, heat capacity, and Poisson’s ratio, thus indicating that it will undergo compressive stress and tensile strain upon heating and cooling. Multiphysics simulation takes this predictive design capability one big step forward by quantifying the resulting displacement due to thermal stress throughout the entire composite structure layup simultaneously, taking into account the properties of all materials. The following figure shows an example of BR&T’s simulation results and presents the stress distribution and displacement throughout the composite structure. Left: Top-down and cross-sectional views of the von Mises stress and displacement in a one-inch square sample of a composite structure layup. Right: Transparency was used to show regions of higher stress, in red. Lower stress is shown in blue. Copyright © Boeing. In the plots at the left above, the displacement pattern caused by the EMF is evident through the paint layer at the top of the composite structure while a magnified cross-sectional view shows the variations in displacement above the mesh and voids of the EMF. The cross section also makes it easy to see the stress distribution through the depth of the composite structure, where there is a trend toward lower stress in the topmost layers. Transparency was used in the plot shown at the right to depict the regions of high stress in the composites and EMF, which is noticeably higher at the intersection of the mesh wires. Stress was plotted through the depth of the composite structure layup along the vertical red line shown in the center of the plot. The figure below shows the relative stress in each layer of the composite structure layup for different metallic compositions of the EMF. Relative stress in arbitrary units was plotted through the depth of the composite structure layups containing either aluminum (left) or copper EMF (right). Copyright © Boeing. The samples vary by the presence of a fiberglass corrosion isolation layer when aluminum is used as the material for the EMF. The fiberglass acts as a buffer resulting in lower stress in the aluminum EMF, when compared with the copper. Designing an EMF Layer for Reliable Lightning Strike Protection From lightning strike protection to the structural integrity of the composite protection scheme, it all relies on the design of the expanded metal foil layer. The design of the EMF layer can vary by its metallic composition, height, width of the mesh wire, and the mesh aspect ratio. For any EMF design parameter, there is a trade-off between current-carrying capacity, displacement, and weight. By using the CTE model, the researchers at BR&T found that increasing the mesh width and decreasing the aspect ratio are better strategies for increasing the current-carrying capacity of the EMF that minimize its impact on displacement in the composite structure. The metal chosen for the EMF can also have a significant effect on stress and displacement in the composite structure, which was investigated using simulation and physical testing. Two composite structures, one with aluminum and the other with copper EMF, underwent thermal cycling with prolonged exposure to moisture in an environmental test chamber. In the results, shown below, the protective layers remained intact for the composite structure with copper EMF. However, for the layup with aluminum, cracking occurred in the primer, at the edges, on surfaces, and was particularly substantial in the mesh overlap regions. Photo micrographs of the composite structure layup after exposure to moisture and thermal cycling. A crack in the vicinity of the aluminum EMF is contained within the red ellipse. Copyright © Boeing. Simulations confirm the experiment results. Shown below, displacements are noticeably higher throughout the composite structure layup when aluminum is used for the EMF layer, where higher displacements are associated with an increased risk for developing cracks. The higher displacement is easiest to observe in the bottom plots, which show displacement ratios for each EMF height. Effect of varying the EMF height on displacement in each layer of the surface protection scheme. Copyright © Boeing. The larger displacements caused by the aluminum EMF can be attributed in part to its higher CTE when compared with copper, which exemplifies how important the properties of materials are to the thermal stability of the aircraft composite structures. In the early design stages and along with experimental testing, multiphysics simulation offers a reliable means to evaluate the relative impact of the EMF design parameters on stress and displacement throughout the composite structures. An optimized EMF design is essential to minimizing the risk of crack formation in the composite surface protection scheme, which reduces maintenance costs and allows the EMF to perform its important protective function of mitigating lightning strike damage. Further Reading Refer to page 4 of COMSOL News 2014 to read the original article, “Boeing Simulates Thermal Expansion in Composites with Expanded Metal Foil for Lightning Strike Protection of Aircraft Structures”. This article was based on the following publicly available resources from Boeing: The Boeing Company. “787 Advanced Composite Design.” 2008-2013. J.D. Morgan, R.B. Greegor, P.K. Ackerman, Q.N. Le, “Thermal Simulation and Testing of Expanded Metal Foils Used for Lightning Protection of Composite Aircraft Structures,” SAE Int. J. Aerosp. 6(2):371-377, 2013, doi:10.4271/2013-01-2132. R.B. Greegor, J.D. Morgan, Q.N. Le, P.K. Ackerman, “Finite Element Modeling and Testing of Expanded Metal Foils Used for Lightning Protection of Composite Aircraft Structures,” Proceedings of 2013 ICOLSE Conference; Seattle, WA, September 18-20, 2013. https://www.comsol.co.in/blogs/protecting-aircraft-composites-from-lightning-strike-damage/

Some more delightful engineering details about the Screamliner to start your week... Protecting Aircraft Composites from Lightning Strike Damage At Boeing, innovation comes in the form of modern aircraft such as the 787 Dreamliner, whose body is made up of over 50% carbon fiber composite. While incredibly lightweight and strong, such aircraft composites are not inherently conductive, thus requiring additional protective coatings to mitigate lightning strike damage. Here, we describe how multiphysics simulation is used to evaluate thermal stress and displacement in the protective coatings that undergo temperature fluctuations associated with the typical flight cycle. High-Performance Coatings for Aircraft Composites Advanced composites are used extensively throughout the Boeing 787 Dreamliner, as shown in the diagram below. Also known as carbon fiber reinforced plastic (CFRP), the composites are formed from a lightweight polymer binder with dispersed carbon fiber filler to produce materials with high strength-to-weight ratios. Many wing components, for example, are made of CFRP, ensuring that they can support the load imposed during flight while minimizing their overall contribution to the weight of an aircraft. Advanced composites are used throughout the body of the Boeing 787. Copyright © Boeing. Despite their remarkable strength and light weight, CFRPs are generally not conductive like their aluminum counterparts, thus making them susceptible to lightning strike damage. Therefore, electrically conductive expanded metal foil (EMF) is added to the composite structure layup, shown in the figure below, to dissipate the high current and heat generated by a lightning strike. The composite structure layup shown at left consists of an expanded metal foil layer shown at right. This figure is a screenshot from the COMSOL Multiphysics® software model featured in this blog post. Copyright © Boeing. The figure also shows the additional coatings on top of the EMF, which are in place to protect it from moisture and environmental species that cause corrosion. Corrosive damage to the EMF could result in lower conductivity, thereby reducing its ability to protect aircraft structures from lightning strike damage. Temperature variations due to the ground-to-air flight cycle can, however, lead to the formation of cracks in the surface protection scheme, reducing its effectiveness. Thermal Stress, Displacement, and Crack Formation During takeoff and landing, aircraft structures are subjected to cooling and heating, respectively. Thermal stress manifests as the expansion and compression — or ultimately the displacement — of adjacent layers throughout the depth of the composite structure. Although a single round-trip is not likely to pose a significant risk, over time, each layer of the composite structure contributes to fatigue damage buildup. Repetitive thermal stress results in cumulative strain and higher displacements, which are, in turn, associated with an increased risk of crack formation. The stresses in a material depend on its mechanical properties quantified by measurable attributes such as yield strength, Young’s modulus, and Poisson’s ratio. Simulating Thermal Stress and the Ground-to-Air Flight Cycle By taking the thermal and mechanical properties of materials into account, it is possible to use simulation to design and optimize a surface protection scheme for aircraft composites that minimizes stress, displacement, and the risk of crack formation. Evaluating the thermal performance of each layer in the surface protection scheme is essential in order to reduce the risks and maintenance costs associated with damage to the protective coating and EMF. Therefore, researchers at Boeing Research & Technology (BR&T), pictured below, are using multiphysics simulation and physical measurements to investigate the effect of the EMF design parameters on stress and displacement throughout the composite structure layup. The research team at Boeing Research & Technology from left to right: Patrice Ackerman, Jeffrey Morgan, Robert Greegor, and Quynhgiao Le. Copyright © Boeing. In their work, the researchers at BR&T have developed a coefficient of thermal expansion (CTE) model in COMSOL Multiphysics® simulation software. The figure shown above that presents the composite structure layup and EMF is a screenshot acquired from the model geometry used for their simulations in COMSOL Multiphysics. The CTE model was used to evaluate heating of the aircraft composite structure as experienced upon descent, where the final and initial temperatures used in the simulations represent the ground and altitude temperatures, respectively. The Thermal Stress interface, which couples heat transfer and solid mechanics, was used in the model to simulate thermal expansion and solve for the displacement throughout the structure. The material properties of each layer in the surface protection scheme as well as of the composites are custom-defined in the CTE model. The relative values of the coefficient of thermal expansion, heat capacity, density, thermal conductivity, Young’s modulus, and Poisson’s ratio are presented in the chart below. This graph presents the ratio of each material parameter relative to the paint layer. Copyright © Boeing.