Tuesday, July 29, 2008

Adaptive Compliant Wing

The Adaptive Compliant Wing is a wing design developed by FlexSys, Inc. which is flexible so that its shape can be changed in flight.

The wing design features a variable-camber trailing edge which can be deflected up to +/- 10°, so that it acts like a flap-equipped wing, but without the individual segments and gaps typical in a flap system. The wing itself can be twisted up to 1° per foot of span. The wing's shape can be changed at a rate of 30° per second, which is ideal for gust load alleviation.

The development of the Adaptive Compliant Wing is being sponsored by the U.S. Air Force Research Laboratory. Initially, the wing was tested in a wind tunnel, and then a 50-inch section of wing was flight tested on board the Scaled Composites White Knight research aircraft in a seven-flight, 20-hour program operated from the Mojave Spaceport.

Monday, July 21, 2008

Reintroduction of the dye transfer process

After its reintroduction in 1997, the dye transfer process was (somewhat unexpectedly) used in several big-budget, modern Hollywood productions. These included Bulworth, Pearl Harbor, and Toy Story. The distinct "look" this process achieves, often sought after by film makers looking to re-create the period of time at which Technicolor was at its most prominent, is difficult to obtain through conventional, high-speed printing methods and is one explanation for the enduring demand and credibility of the process.

The latest motion picture dye IB (imbibition) transfer process developed during the 1990s is greatly superior to the process used during the 1970s and of much higher quality than modern Eastmancolor stocks. The prints exhibited a higher color gamut and color satauration than modern Eastmancolor stock and could be made consistently and accurately for large numbers of prints. There were no longer visible density and contrast variations that occurred most often with earlier three color Technicolor. The new process was also about as sharp as modern Eastmancolor process with slightly higher contrast, but they appeared sharper due to the higher contrast.

Technicolor was purchased by French company Thomson in 2001 from the British company Carlton Communications, which discontinued the dye-transfer process in 2002.
The visual aesthetic of dye transfer Technicolor continues to be used in Hollywood, usually in films set in the mid-20th century. Parts of The Aviator, the 2004 biopic of Howard Hughes, were digitally manipulated to imitate color processes that were available during the periods each scene takes place. The two-color look of the film is incorrectly cited as looking like Technicolor's two-color systems, and is in fact a facsimile of Hughes' own color system, Multicolor. The "three-strip" Technicolor look begins after the newsreel footage of Hughes making the first flight around the world.

Tuesday, July 15, 2008

Geological paradigm shift

The acceptance of the theories of continental drift and sea floor spreading (the two key elements of plate tectonics) may be compared to the Copernican revolution in astronomy (see Nicolaus Copernicus). Within a matter of only several years geophysics and geology in particular were revolutionized. The parallel is striking: just as pre-Copernican astronomy was highly descriptive but still unable to provide explanations for the motions of celestial objects, pre-tectonic plate geological theories described what was observed but struggled to provide any fundamental mechanisms. The problem lay in the question "How?". Before acceptance of plate tectonics, geology in particular was trapped in a "pre-Copernican" box.

However, by comparison to astronomy the geological revolution was much more sudden. What had been rejected for decades by any respectable scientific journal was eagerly accepted within a few short years in the 1960s and 1970s. Any geological description before this had been highly descriptive. All the rocks were described and assorted reasons, sometimes in excruciating detail, were given for why they were where they are. The descriptions are still valid. The reasons, however, today sound much like pre-Copernican astronomy.

One simply has to read the pre-plate descriptions of why the Alps or Himalaya exist to see the difference. In an attempt to answer "how" questions like "How can rocks that are clearly marine in origin exist thousands of meters above sea-level in the Dolomites?", or "How did the convex and concave margins of the Alpine chain form?", any true insight was hidden by complexity that boiled down to technical jargon without much fundamental insight as to the underlying mechanics.

With plate tectonics answers quickly fell into place or a path to the answer became clear. Collisions of converging plates had the force to lift the sea floor to great heights. The cause of marine trenches oddly placed just off island arcs or continents and their associated volcanoes became clear when the processes of subduction at converging plates were understood.

Mysteries were no longer mysteries. Forests of complex and obtuse answers were swept away. Why were there striking parallels in the geology of parts of Africa and South America? Why did Africa and South America look strangely like two pieces that should fit to anyone having done a jigsaw puzzle? Look at some pre-tectonics explanations for complexity. For simplicity and one that explained a great deal more look at plate tectonics. A great rift, similar to the Great Rift Valley in northeastern Africa, had split apart a single continent, eventually forming the Atlantic Ocean, and the forces were still at work in the Mid-Atlantic Ridge.

We have inherited some of the old terminology, but the underlying concept is as radical and simple as was "The Earth moves" in astronomy.

Monday, July 07, 2008

Dried plasma

"Dried plasma" was developed and first used in WWII. Prior to the United States' involvement in the war, liquid plasma and whole blood were used. The "Blood for Britain" program during the early 1940s was quite successful (and popular in the United States) based in part on Dr. Charles Drew's contribution. A large project was begun in August of the year 1940 to collect blood in New York City hospitals for the export of plasma to Britain. Dr. Drew was appointed medical supervisor of the "Plasma for Britain" project. His notable contribution at this time was to transform the test tube methods of many blood researchers, including himself, into the first successful mass production techniques.

Nonetheless, the decision was made to develop a dried plasma package for the armed forces as it would reduce breakage and make the transportation, packaging, and storage much simpler.

The resulting Army-Navy dried plasma package came in two tin cans containing 400 cc bottles. One bottle contained enough distilled water to completely reconstitute the dried plasma contained within the other bottle. In about three minutes, the plasma would be ready to use and could stay fresh for around four hours.

Following the "Plasma for Britain" invention, Dr. Drew was named director of the Red Cross blood bank and assistant director of the National Research Council, in charge of blood collection for the United States Army and Navy. Dr. Drew argued against the armed forces directive that blood/plasma was to be separated by the race of the donor. Dr. Drew argued that there was no racial difference in human blood and that the policy would lead to needless deaths as soldiers and sailors were required to wait for "same race" blood.[citation needed]

By the end of the war the American Red Cross had provided enough blood for over six million plasma packages. Most of the surplus plasma was returned to the United States for civilian use. Serum albumin replaced dried plasma for combat use during the Korean War.

Tuesday, July 01, 2008

Deoxyribonucleic acid (DNA)

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.

Chemically, DNA consists of two long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups joined by ester bonds. These two strands run in opposite directions to each other and are therefore anti-parallel. Attached to each sugar is one of four types of molecules called bases. It is the sequence of these four bases along the backbone that encodes information. This information is read using the genetic code, which specifies the sequence of the amino acids within proteins. The code is read by copying stretches of DNA into the related nucleic acid RNA, in a process called transcription.

Within cells, DNA is organized into structures called chromosomes. These chromosomes are duplicated before cells divide, in a process called DNA replication. Eukaryotic organisms (animals, plants, and fungi) store their DNA inside the cell nucleus, while in prokaryotes (bacteria and archae) it is found in the cell's cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.