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The structures have potential applications in drug delivery to treat diseases and imaging for cancer research. Two types of nanotubes are created in the manufacturing process, metallic and semiconducting. Until now, however, there has been no technique to see both types in living cells and the bloodstream, said Ji-Xin Cheng, an associate professor of biomedical engineering and chemistry at Purdue University.

The imaging technique, called transient absorption, uses a pulsing near-infrared laser to deposit energy into the nanotubes, which then are probed by a second near-infrared laser.

The researchers have overcome key obstacles in using the imaging technology, detecting and monitoring the nanotubes in live cells and laboratory mice, Cheng said.

"Because we can do this at high speed, we can see what's happening in real time as the nanotubes are circulating in the bloodstream," he said.

Findings are detailed in a research paper posted online Sunday (Dec. 4) in the journal Nature Nanotechnology.

The imaging technique is "label free," meaning it does not require that the nanotubes be marked with dyes, making it potentially practical for research and medicine, Cheng said.

"It's a fundamental tool for research that will provide information for the scientific community to learn how to perfect the use of nanotubes for biomedical and clinical applications," he said.

The conventional imaging method uses luminescence, which is limited because it detects the semiconducting nanotubes but not the metallic ones.

The nanotubes have a diameter of about 1 nanometer, or roughly the length of 10 hydrogen atoms strung together, making them far too small to be seen with a conventional light microscope. One challenge in using the transient absorption imaging system for living cells was to eliminate the interference caused by the background glow of red blood cells, which is brighter than the nanotubes.

The researchers solved this problem by separating the signals from red blood cells and nanotubes in two separate "channels." Light from the red blood cells is slightly delayed compared to light emitted by the nanotubes. The two types of signals are "phase separated" by restricting them to different channels based on this delay.

Researchers used the technique to see nanotubes circulating in the blood vessels of mice earlobes.

"This is important for drug delivery because you want to know how long nanotubes remain in blood vessels after they are injected," Cheng said. "So you need to visualize them in real time circulating in the bloodstream."

The structures, called single-wall carbon nanotubes, are formed by rolling up a one-atom-thick layer of graphite called graphene. The nanotubes are inherently hydrophobic, so some of the nanotubes used in the study were coated with DNA to make them water-soluble, which is required for them to be transported in the bloodstream and into cells.

The researchers also have taken images of nanotubes in the liver and other organs to study their distribution in mice, and they are using the imaging technique to study other nanomaterials such as graphene.

More information: Label-Free Imaging of Semiconducting and Metallic Carbon Nanotubes in Cells and Mice Using Transient Absorption Microscopy, Nature Nanotechnology.

Source: PhysOrg

 

The incorporation of such single-molecule elements could enable smaller, faster, and more energy-efficient electronics.

The research findings, supported by a $1 million grant from the W.M. Keck Foundation, were published online in the Nov. 14 issue of Nano Letters.

"This new switch is superior to existing single-molecule concepts," said Hrvoje Petek, principal investigator and professor of physics and chemistry in the Kenneth P. Dietrich School of Arts and Sciences and codirector of the Petersen Institute for NanoScience and Engineering (PINSE) at Pitt. "We are learning how to reduce electronic circuit elements to single molecules for a new generation of enhanced and more sustainable technologies."

The switch was discovered by experimenting with the rotation of a triangular cluster of three metal atoms held together by a nitrogen atom, which is enclosed entirely within a cage made up entirely of carbon atoms. Petek and his team found that the metal clusters encapsulated within a hollow carbon cage could rotate between several structures under the stimulation of electrons. This rotation changes the molecule's ability to conduct an electric current, thereby switching among multiple logic states without changing the spherical shape of the carbon cage. Petek says this concept also protects the molecule so it can function without influence from outside chemicals.

Because of their constant spherical shape, the prototype molecular switches can be integrated as atom-like building blocks the size of one nanometer (100,000 times smaller than the diameter of a human hair) into massively parallel computing architectures.

The prototype was demonstrated using an Sc3N@C80 molecule sandwiched between two electrodes consisting of an atomically flat copper oxide substrate and an atomically sharp tungsten tip. By applying a voltage pulse, the equilateral triangle-shaped Sc3N could be rotated predictably among six logic states.

The research was led by Petek in collaboration with chemists at the Leibnitz Institute for Solid State Research in Dresden, Germany, and theoreticians at the University of Science and Technology of China in Hefei, People's Republic of China. The experiments were performed by postdoctoral researcher Tian Huang and research assistant professor Min Feng, both in Pitt's Department of Physics and Astronomy.

Source: ScienceDaily

 

Switching from hydrocarbon-based transportation to systems powered by state-of-the-art fuel cells therefore seems a natural choice, but numerous obstacles have kept this technology confined to laboratories. A prime example is the problem of on-board hydrogen storage for vehicles: because ambient hydrogen gas is roughly 10,000 times less dense than gasoline, it would require impractically large tanks to obtain comparable mileage.

Compressing hydrogen gas or liquefying it at -250 °C are two ways to increase its energy content by volume. However, chemists are developing a more attractive strategy using specially designed compounds, called metal hydride clusters, to produce high hydrogen-storage densities without extreme temperatures or pressures. The metal atoms within these molecules bind to large numbers of hydrogen atoms, producing a solid that can reversibly add or remove hydrogen using mild heating or cooling.

Now, Zhaomin Hou from the RIKEN Advanced Science Institute in Wako and an international team of colleagues have isolated a new class of ‘heterometallic’ hydride clusters (Fig. 1) that may spur development of lighter and longer-lived fuel cell devices. By incorporating multinuclear rare-earth metals into their compounds, the team has produced the first high-density storage molecules that have hydrogen addition properties that can be monitored directly using x-ray diffraction—a technique that provides clear insights into cluster structure and functionality.

Rare combinations

For the past 25 years, chemists have paired so-called ‘d-block transition metals’, such as tungsten (W) and molybdenum (Mo), with lightweight rare-earth metals, such as yttrium (Y), to increase the storage capacity of hydride clusters. Because the nuclei of rare earths are shielded by many electrons, these metals can pack high numbers of hydrogen atoms into small crystal volumes without suffering electronic repulsions. Unfortunately, once hydrogen gas binds to a rare-earth metal, it tends to stay there. Mixing in d-block metals alters the rare-earth reactivity so that on-demand hydrogen storage and release can occur.

Figure 1: Heterometallic hydride clusters containing molybdenum atoms (purple spheres) and rare-earth yttrium metals (green spheres) are promising materials for on-board storage and release of hydrogen gas (light blue spheres). Credit: 2011 Zhaomin Hou

Until now, most of these combined metal hydrides were constructed using mononuclear rare-earth building blocks, such as YH, with a mononuclear d-block metal. Using a different strategy, Hou and his colleagues recently devised innovative protocols to isolate polynuclear rare-earth hydrides using large molecular ligands to trap these typically unstable compounds in place. Polynuclear hydrides feature dense, interconnected networks of ‘bridging’ hydrogen atoms connected to two or more metals—characteristics that led the researchers to explore their potential for hydrogen storage applications.

“It is not difficult to imagine that hydrogen atoms could bond to multiple metal atoms in a polynuclear polyhydride complex, and the [mode of] bonding could be different with different metal combinations,” says Hou. “However, it is not easy to prepare quality polyhydride samples for high-precision structure determinations. Hydride complexes containing both rare-earth and d-block transition metals are even more difficult to prepare because of their air- and moisture-sensitivity.”

A five-way first


Figure 2: Monitoring the reversible addition and release of a hydrogen gas molecule to a molybdenum-yttrium cluster in real time with x-ray crystallography has revealed the first atom-resolved insights into hydrogen storage by organometallic crystals. Credit: 2011 Zhaomin Hou

Performing their experiments inside nitrogen-filled and humidity-free enclosures, the team mixed one of their carefully prepared polynuclear complexes—four yttrium metals and eight hydrogen atoms held together by bulky organic ligands—with either a Mo or W pentahydride. After precipitating crystals out of the reaction, they used x-ray and neutron diffraction experiments to view their product’s atomic structure. These measurements showed that the two metallic components fused together, yielding a Y4MH11 (M = Mo, W) hydride with double-, triple-, and quadruple-bridged hydrogen atoms.

Zapping the penta-metallic polyhydride with ultraviolet light enabled the team to remove a protective phosphorus ligand and increase the hydrogen bridging density within the cluster. This produced the first hydride cluster where hydrogen is bonded to five metals in a distinctive symmetry known as trigonal bipyramidal. “The confirmation of a penta-coordinated hydrogen atom in this geometry is unprecedented,” says Hou.

Step-by-step scrutiny

Hou and colleagues’ experiments then demonstrated that their heterometallic clusters possessed critical hydrogen storage and release capabilities. Heating H2 and Y4WH11 to 80 °C caused an oxidative addition of the gas molecule to the cluster, which they could reverse through ultraviolet-light treatment. Despite the Y4MoH11 molecule not responding to the same chemical tricks, the researchers discovered that applying a vacuum could suck H2 from the cluster, giving a new Y4MoH9 complex. Exposing this compound to hydrogen gas at room temperature spontaneously regenerated the original molecule (Fig. 2).

According to Hou, the most striking aspect of this chemistry is that the hydrogen addition to the Y4MoH9 cluster can be followed from single crystal to single crystal—meaning that the starting material, the reaction intermediates, and the product all retain the same rigid morphology. “No metal hydrides have previously shown such excellent crystallinity,” he notes.

After gingerly sealing a Y4MoH9 crystal into a thin, hydrogen-filled capillary tube, the researchers monitored the spontaneous addition reaction over 60 hours. As the cluster gradually took in hydrogen and changed color from black to red, they watched—at precision greater than one-millionth of a meter—yttrium and molybdenum atoms separate and shift within the crystal unit cell. By providing the first-ever atom-resolved views of active sites and bonding modes for hydrogen addition to an organometallic crystal, these findings should aid design of more sophisticated alloys in the future.

Theoretical calculations performed by the researchers indicated that combining two metals with starkly different electronic properties played a big role in giving the clusters their unique reactivity. With wide swaths of the periodic table available for exploring using this technique, breakthroughs in heterometallic hydride materials may have only just begun.

Source: RIKEN

 

These hydrogels have potential as injectable materials for medical applications, e.g., liquid injection agents that become gelatinous in the human body to keep drugs around cancerous tumors. In this study, scientists from Kansas State University, University of Nebraska, and PNNL used two native functional sequences from spider flagelliform silk protein and a trans-membrane motif of human muscle L-type calcium channel to design a self-assembling peptide, h9e.

The h9e peptide formed two novel hydrogels in Ca2+ solution and acidic pH conditions—h9e Ca2+ hydrogel and h9e acidic hydrogel. The shear-thinning, rapid-strength-recovering h9e Ca2+ hydrogel proved to have potential for drug delivery and tissue-engineering applications and was tested on mice as an injectable adjuvant for H1N1 swine influenza virus killed vaccine. The study showed it was biologically safe, improved immune response on killed H1N1 virus antigen by approximately 70%, and induced a similar H1N1-specific IgG1 antibody response compared with an oil-based commercial adjuvant.

To assess these rationally designed peptide hydrogels, the researchers used electrospray ionization followed by analysis of the resulting ions in an LTQ-Orbitrap high-resolution mass spectrometer at EMSL. The mass spectrometry experiments were conducted to identify possible precursors of the peptide assembly and nanofiber crossing, as well as the binding mode of calcium to the peptides.

Source: Medical Xpress

 
By Admin (from 02/02/2012 @ 08:04:09, in en - Science and Society, read 1255 times)

Technology for making an "artificial leaf" holds the potential for opening an era of "fast-food energy," in which people generate their own electricity at home with low-cost equipment perfect for the 3 billion people living in developing countries and even home-owners in the United States. That's among the prospects emerging from research on a new genre of "electrofuels" described in the current edition of Chemical & Engineering News, the American Chemical Society's weekly newsmagazine.

In the article, C&EN Senior Correspondent Stephen K. Ritter describes research on electrofuels, made by using energy from the sun and renewable ingredients like water and carbon dioxide, reported at a gathering of experts sponsored by the U. S. Department of Energy's Advanced Research Projects Agency (ARPA-E). Created in 2009 by the American Recovery & Reinvestment Act, ARPA-E is funding electrofuels research, with the goal of developing technologies that improve on nature's approach — photosynthesis. Electrofuels is one of 12 programs funded by ARPA-E.

The artificial leaf is one of the electrofuels technologies. Made of inexpensive materials, the leaf breaks down ordinary water into the oxygen and hydrogen that can power an electricity-producing fuel cell. Just drop the credit-card-sized device into a bucket of water and expose it to sunlight. With the cost-conscious technology, one door-sized solar cell and three gallons of water could produce a day's worth of electricity for a typical American home. The article describes a range of other electrofuel technologies, including ones based on engineered microbes, being developed in the quest for new ways of making fuels.

Source: PhysOrg - via ZeitNews

 

The Ford Dome

In 1953, Fuller and his geodesic dome were elevated to international prominence when the first conspicuous commercial geodesic dome was produced. That structure was erected in answer to a Ford Motor Company problem believed to be insoluble.  During 1952, Ford was in the process of preparing for its fiftieth anniversary celebration the following year, and Henry Ford II, grandson of Henry Ford and head of the company, decided he wanted to fulfill one of his grandfather's dreams as a tribute to the company's founder.  The senior Ford had always loved the round corporate headquarters building known as the Rotunda but had wanted its interior courtyard covered so that the space could be used during inclement Detroit weather.

File:Eden Project geodesic domes panorama.jpg

Panoramic view of the geodesic domes at the The Eden Project

Unfortunately -- but fortunately for Bucky -- the building was fairly weak. It had originally been constructed to house the Ford exhibition at the Chicago World's Fair of 1933, but Henry Ford had so loved the building that he had had it disassembled and shipped in pieces to Dearborn, where it was reconstructed. Having been designed as a temporary structure, the fragile Rotunda building could not possibly support the 160-ton weight that Ford's engineers calculated conventional steel-frame dome would require.  Under such pressure, the building's thin walls would have immediately collapsed.

Still, Henry Ford II was a determined person, and he wanted the courtyard covered.  Consequently, Ford management and engineers continued searching for an answer until someone suggested calling Buckminster Fuller.  By that time, Fuller's work drawing international attention, and although his geodesic dome had yet to be proven effective in an industrial project, desperate Ford officials decided they should at least solicit Bucky's opinion.  When he arrives at the Detroit airport, Fuller was greeted by a Ford executive in a large limousine who treated him like royalty, quickly escorting him to the Rotunda building for an inspection.  After a short examination of the 93-foot opening requiring a dome, Ford management asked the critical question: Could Fuller build a dome to cover the courtyard?  With no hesitation, Bucky answered that he certainly could, and the first commercial geodesic dome began to take shape.

The Ford executives next began to question the specifications of Fuller's plan.  When they asked about weight, he made some calculations and answered that his dome would weigh approximately 8.5 tons, a far cry from their 160-ton estimate.  Ford management also requested a cost estimate and advised Fuller that, because of the upcoming anniversay celebration, the dome had to be completed within the relatively short period of a few months.  When Fuller's price was well below Ford's budget and he agreed to construct the dome within the required time frame, he was awarded a contract.

The agreement was signed in January of 1953, and Bucky immediately began working to meet the April deadline.  The somewhat discredited Ford engineers who had failed to develop a practical solution were, however, not convinced that the obscure inventor's fantastic claims were valid.  Thus, they began working on a contingency plan that would prevent further reputations further, the engineers secretly contracted another construction firm to hastily haul away any evidence of Fuller's work when he failed.  The Ford engineers were once again proven wrong when the dome was successfully completed in April, two days ahead of schedule.

Building from the Top Down

Actual construction of the dome was a marvel to behold.  Reporters from around the world gathered to witness and recount the architectural effort as well as Ford's anniversary celebration.  Because the courtyard below the dome was to be used for a television special commemorating the anniversary, and because business at Ford had to proceed normally, Fuller's crew was provided with a tiny working area and instructed to keep disruptions to a minimum.

Ford management was also concerned with the safety of both the dome workers and the people who might wander beneath the construction.  They anticipated that problems would arise when Ford employees, television crews, reporters, and spectators gathered below to observe the construction workers climbing high overhead on the treacherous scaffolding, but once again Bucky surprised everyone.  Instead of traditional scaffolding, he employed a strategy similar to the one he developed in 1940 for the quick assembly of his Dymaxion Deployment Units.

Because the sections of the dome were prefabricated and then suspended from a central mast, no dangerous scaffolding was required.  The construction team worked from a bridge erected across the top of the Rotunda courtyard.  Like Dymaxion Deployment Units, the Ford dome was then built from the top down while being hoisted higher and rotated each time a section was completed.  The dome was assembled from nearly 12,000 aluminum struts, each about three feet long and weighing only five ounces.  Those struts were preassembled into octet-truss, equilateral-triangular sections approximately 15 feet on a side. Since each section weighed only about four pounds and could be raised by a single person, no crane or heavy machinery was required to hoist them to the upper bridge assembly area.

Once on the working bridge, the identical sections were riveted into place on the outwardly growing framework until it covered the entire courtyard.  Upon completion, the 8.5-ton dome remained suspended on its mast, hovering slightly above the building itself until the mooring points were prepared.  Then, it was gently lowered down onto the Rotunda building structure with no problem.

To complete the first commercial geodesic dome, clear Fiberglas "windows" were installed in the small triangular panels of the framework.  Because Fuller had not yet developed or determined the best means of fastening those panels, they would eventually be a cause of the destruction of the dome and the building itself.

Since it was the first large functional geodesic dome, many aspects of the Ford dome were experimental.  They had been tested in models, but how the dome and the materials utilized would withstand the forces of Michigan winters could be determined only by the test of time.  The Rotunda building dome did perform successfully for several years before the elements began taking their toll and leaks between the Fiberglas and the aluminum began to occur.  Still, with regular maintenance, that problem was not serious, and convening corporate events under the dome became a tradition.  One of those events was the annual Ford Christmas gathering.

In 1962, numerous leaks in the dome were noticed as the Christmas season approached, and a maintenance crew was dispatched one cold late-autumn day to repair the problem.  The temperature was, however, too cold to permit proper heating of the tar they used for the repairs, and, in a common practice, the workers added gasoline to thin the tar.  They were warming the tar with a blowtorch when that potent mixture ignited, and the building quickly caught fire.  Since the building had never been planned as a permanent structure, it was not long before the entire Rotunda was engulfed in flames that destroyed the first commercial geodesic dome, the singular structure that, more than any other, had catapulted Fuller to public fame.

Doing More with Less

The notoriety provided by the Ford project resulted in an enormous amount of nearly instant public interest in Fuller and his ideas.  It also brought him to the attention of a group of scientists who were struggling with another seemingly unsolvable problem: protection of the Distant Early Warning Line radar installations throughout the Arctic.  Once again, Fuller and his amazing geodesic dome surprised all the experts as his hastily invented Fiberglas "radomes" proved more than able to handle that difficult task.

The proliferation of radomes in technologically advanced situations around the world moved the geodesic dome into its rightful position as a symbol of developing humanity doing more and more with fewer resources.  Thus, geodesic domes are now employed for diverse tasks such as providing a more natural structure for children on playgrounds, covering athletic stadiums, and being proposed for use in future space construction.

However, the true significance of the geodesic dome is most evident in the fact that it is often the dominant symbol employed at major future-oriented expositions.  When most people remember the 1967 Montreal World's Fair, the 1986 Vancouver World's Fair, or Disney's EPCOT Center, the first image they recall is the geodesic dome.

It properly stands as a monument to the work of Buckminster Fuller, who successfully shared his vision of a world that works for everyone.  He also inspired scores of people to work, as he did, to establish a network of equally significant individuals supporting humanity's emergence into a new era of cooperation.  That relationship between individual human beings, as well as that between humans and their environment, is not modeled by the rigid conventional buildings that fill our environment.  It is modeled in the amazing geodesic dome's network of lightweight, resilient struts, wires, and panels.

Lloyd Steven Sieden is an author, lecturer, and consultant whose primary concentration is helping businesses, organizations, and individuals apply Buckminster Fuller's ideas and solutions to practical issues.  His address is Sieden & Associates, 32921 Avenida Descanso, San Juan Capistrano, California 92675.

This article is adapted from his book Buckminster Fuller's Universe: An Appreciation (Plenum Press, 1989), which is available from the Futurist Bookstore.  See page 42 for details.

=============================================

THE END.

Source: insite.com

 

... CONTINUES.

A New Form of Architecture

In 1948, the geodesic dome was far from the amazingly sophisticated structure it would become only a few years later.  In fact, it consisted primarily of Bucky's idea and an enormous pile of calculations he had formulated.

Although Fuller was developing and studying the geodesic dome using small models, he was eager to expand his understanding through the construction of larger, more-practical projects.  Thus, when he was invited to participate in the summer institute of the somewhat notorious Black Mountain College in the remote hills of North Carolina near Asheville, Fuller eagerly accepted.  He had lectured at that rather unorthodox institution the previous year and had been so popular that he was asked back for the entire summer of 1948.

When he was not delivering lengthy thinking-out-loud lectures that summer, Fuller's primary concern was furthering an entirely new form of architecture. In his examination of traditional construction, he had discovered that most buildings focused on right-angle, squared configurations.

He understood that early human beings had developed that mode of construction without much thought by simply piling stone upon stone.  Such a simplistic system was acceptable for small structures, but when architects continued mindlessly utilizing that same technique for large buildings, major problems arose.  The primary issue created by merely stacking materials higher and higher is that taller walls require thicker and thicker base sections to support their upper sections.  Some designers attempted to circumvent that issue by using external buttressing, which kept walls from crumbling under the weight of upper levels, but even buttressing limited the size.

Fuller found that the compression force (i.e., pushing down) that caused such failure in heavy walls was always balanced by an equal amount of tensional force (i.e., pulling, which in buildings is seen in the natural tendency of walls to arc outward) in the structure.  In fact, he discovered that if tension and compression are not perfectly balanced in a structure, the building will collapse.  He also found that builders were not employing the tensional forces available.  Those forces are, instead, channeled into the ground, where solid foundations hold the compressional members, be they stones or steel beams, from being thrust outward by tension.  Always seeking maximum efficiency, Fuller attempted to employ tensional forces in his new construction idea.  The result was geodesic structures.

Because Bucky could not afford even the crude mechanical multiplier machines available during the late 1940s and was working with nothing but an adding machine, his first major dome required two years of calculations.  With the help of a young assistant, Donald Richter, Fuller was, however, able to complete those calculations.  Thus, he brought most of the material needed to construct the first geodesic dome to Black Mountain in the summer of 1948.

File:Dymaxion house.jpg

A Dymaxion House at The Henry Ford.

Disappointment before Success

His vision was of a 50-foot-diameter framework fabricated from lightweight aluminum, and, working with an austere budget, he had purchased a load of aluminum-alloy venetian-blind strips that he packed into the car for the trip to the college.  Over the course of that summer, Bucky also procured other materials locally, but he was not completely satisfied with the dome's constituent elements, which were neither custom-designed for the project nor of the best materials.  Still, with the help of his students, the revolutionary new dome was prepared for what was supposed to be a quick assembly in early September, just as the summer session was coming to an end.

The big day was dampened by a pouring rain.  Nonetheless, Bucky and his team of assistants scurried around the field that had been chosen as the site of the event, preparing the sections of their dome for final assembly, while faculty and students stood under umbrellas, watching in anticipation from a nearby hillside.  When the critical moment arrived, the final bolts were fastened and tension was applied to the structure, causing it to transform from a flat pile of components into the world's first large geodesic sphere. The spectators cheered, but their excitement lasted only an instant as the fragile dome almost immediately sagged in upon itself and collapsed, ending the project.

Although he must have been disappointed that day, Bucky's stoic New England character kept him from publicly acknowledging such emotion.  Instead, he maintained that he had deliberately designed an extremely weak structure in order to determine the critical point at which it would collapse and that he had learned a great deal from the experiment.  Certainly, the lessons learned from that episode were valuable, and his somewhat egocentric rationale was by no means a blatant lie.  However, had he really been attempting to find the point of destruction, Bucky would have proceeded, as he did in later years, to add weights to the completed framework until it broke down.

In his haste to test his calculations, Fuller had proceeded without the finances necessary to acquire the best materials.  Because of the use of substandard components, the dome was doomed to failure, and a demonstration of the geodesic dome's practical strength was condemned to wait another year.

During that year, Fuller taught at the Chicago Institute of Design.  He and his Institute students also devoted a great deal of time to developing his new concepts.  It was with the assistance of those design students that Fuller built a number of more successful dome models, each of which was more structurally sound than the previous one.

Then, when he was invited to return to Black Mountain College the following summer as dean of the Summer Institute, Fuller suggested that some of his best Chicago Institute students and their faculty accompany him, so that they could demonstrate the true potential of geodesic domes.

Having earned some substantial lecture fees during the previous year, Bucky was able to purchase the best of materials for his new Black Mountain dome. The project was a 14-foot-diameter hemisphere constructed of the finest aluminum aircraft tubing and covered with a vinyl-plastic skin.  Completely erected within days after his arrival, that dome remained a stable fixture on the campus throughout the summer.  To further prove the efficiency of the design to somewhat skeptical fellow instructors and students, Bucky and eight of his assistants daringly hung from the structure's framework, like children on a playground, immediately after its completion.

TO BE CONTINUED...

 

Citation:    The Futurist, Nov-Dec 1989 v23 n6 p14(5)

------------------------------------------------------------------------------

Title:       The birth of the geodesic dome; how Bucky did it. (R. Buckminster Fuller)

Authors:     Sieden, Lloyd Steven

------------------------------------------------------------------------------

Subjects:    Geodesic domes_research & Dwellings_innovations

People:      Fuller, R. Buckminster_innovations

Reference #: A8121293

=============================================

Richard Buckminster Fuller, c. 1917.
Born: July 12, 1895
Milton, Massachusetts, United States
Died: July 1, 1983 (aged 87)
Los Angeles, United States
Occupation: designer, author, inventor
Spouse: Anne Fuller
Children 2: Allegra Fuller Snyder and Alexandra who died in childhood 

 

Full Text COPYRIGHT World Future Society 1989

The Birth of The Geodesic Dome

Although Buckminster Fuller invariably maintained that he was a comprehensivist who was interested in almost everything, his life and work were dominated by a single issue: shelter and housing.  Even as a young boy in the early 1900s, Fuller--who preferred to be called Bucky--was constructing rudimentary structures and inventing better "environment controlling artifacts."

The practical culmination of his quest to employ modern assembly-line manufacturing techniques and the best man-made materials in producing inexpensive, elegant housing came toward the end of World War II.  At that time, government officials contracted Fuller to build two prototype Dymaxion Houses at the Beech Aircraft Company in Wichita, Kansas.

The lightweight, circular houses were praised by all who toured them.  Because the Dymaxion House was to provide many new innovations at the very affordable suggested retail price of $6,500, orders flowed into the factory before plans for distribution were seriously considered.  However, Fuller's interests were not geared toward practical matters such as financing and marketing, and the

Dymaxion House never advanced beyond the prototype stage.  Fuller then moved on to consider other innovations that could benefit humanity in the areas of structure and housing.

He also returned to his less pragmatic quest to discover nature's coordinate system and employ that system in a structure that would, because it was based on natural rather than humanly developed principles, be extremely efficient. That structure is the geodesic dome, which, because it approximates a sphere, encloses much more space with far less material than conventional buildings.

In order to uncover nature's coordinate system, Fuller retreated from a great deal of his usual activities during 1947 and 1948.  The primary focus of that retreat was a single topic: spherical geometry.  He chose that area because he felt it would be most useful in further understanding the mathematics of engineering, in discovering nature's coordinate system, and eventually in building the spherical structures that he found to be the most efficient means of construction.

Dome Models

Having observed the problems inherent in conventional construction techniques (as opposed to the ease with which nature's structures are erected) and the indigenous strength of natural structures, Fuller felt certain that he could perfect an analogous, efficient, spherical-construction technique.  He was also aware that any such method would have to be predicated upon spherical trigonometry.  To do that, Bucky converted the small Long Island apartment that his wife, Anne, had rented into a combination workshop and classroom where he studied and discussed his ideas with others.

As those ideas started to take shape in the models and drawings he used for sharing his insights, Fuller considered names for his invention.  He selected "geodesic dome" because the sections or arcs of great circles (i.e., the shortest distance between two points on a sphere) are called geodesics, a term derived from the Greek word meaning "earth-dividing."  His initial dome models were nothing more than spheres or sections of spheres constructed from crisscrossing curved pieces of material (each of which represented an arc of a great circle) that formed triangles.  Later, he expanded the concept and formed the curved pieces into even more complex structures such as tetrahedrons or octahedrons, which were then joined to create a spherical structure.  Still, the simple triangulation of struts remained, as did the initial name of the invention.

Although Fuller's study of mathematics played a significant role in his invention of the geodesic dome, that process was also greatly influenced by his earlier extensive examination of and work within the field of construction.  During his construction experience, he came to realize that the dome pattern had been employed, to some extent, ever since humans began building structures.  Early sailors landing upon foreign shores and requiring immediate shelter would simply upend their ships, creating an arched shelter similar to a dome.

Land-dwelling societies copied that structure by locating a small clearing surrounded by young saplings and bending those uncut trees inward to form a dome that they covered with animal skins, thatch, or other materials.  Over time, that structure developed into the classic yurt that still provides viable homes for many people in and around Afghanistan and the plains of the Soviet Union.

TO BE CONTINUED...

 

“This is a novel application of existing materials, and has potential for rapid, high-volume manufacturing processes or packaging applications,” says Dr. Michael Dickey, an assistant professor of chemical and biomolecular engineering at NC State and co-author of a paper describing the research.

The process is remarkably simple. Researchers take a pre-stressed plastic sheet and run it through a conventional inkjet printer to print bold black lines on the material. The material is then cut into a desired pattern and placed under an infrared light, such as a heat lamp.

The bold black lines absorb more energy than the rest of the material, causing the plastic to contract – creating a hinge that folds the sheets into 3-D shapes. This technique can be used to create a variety of objects, such as cubes or pyramids, without ever having to physically touch the material. The technique is compatible with commercial printing techniques, such as screen printing, roll-to-roll printing, and inkjet printing, that are inexpensive and high-throughput but inherently 2-D.

By varying the width of the black lines, or hinges, researchers are able to change how far each hinge folds. For example, they can create a hinge that folds 90 degrees for a cube, or a hinge that folds 120 degrees for a pyramid. The wider the hinge, the further it folds. Wider hinges also fold faster, because there is more surface area to absorb energy.

“You can also pattern the lines on either side of the material,” Dickey says, “which causes the hinges to fold in different directions. This allows you to create more complex structures.”

The researchers developed a computer-based model to explain how the process works. There were two key findings. First, the surface temperature of the hinge must exceed the glass transition temperature of the material, which is the point at which the material begins to soften. Second, the heat has to be localized to the hinge in order to have fast and effective folding. If all of the material is heated to the glass transition temperature, no folding will occur.

“This finding stems from work we were doing on shape memory polymers, in part to satisfy our own curiosity. As it turns out, it works incredibly well,” Dickey says.

Source: North Carolina State University

 

The thing about growing working organs in the lab is that the whole enterprise is completely mind-blowing. Yet we just keep doing it, and so we keep blowing minds. The latest: a team of researchers at Japan’s RIKEN Center--the same group who earlier this year engineered a mouse retina that is the most complex tissue ever engineered--have now derived a working pituitary gland from mouse stem cells.

That’s saying something. For one, the pituitary gland is an integral part of the body’s endocrine system. From it’s position at the base of the brain it doles out key developmental hormones that instruct the body on how to grow and develop over time. But perhaps more importantly, the pituitary gland cannot itself develop without special chemical instructions from the hypothalamus (the brain region just above it).

That’s a serious bioengineering problem, because in order to grow a working pituitary gland in the lab you need a hypothalamus--or at least a hypothalamus analog--to tell it how to develop. The researchers overcame this with a 3-D cell culture and some good old fashioned trial and error. They had a notion of what kind of signaling factors would be needed to make a proper pituitary gland grow and tried combinations until they found the right fit.

The result is a working pituitary that expressed the right hormones and the right biomarkers. And to remove any doubt, the researchers implanted their lab-grown glands into mice with pituitary defects. The mice quickly showed restored levels of key pituitary hormones and behavioral symptoms of pituitary problems disappeared. These pituitary glands, by all appearances, seem to work like the original biological glands were meant to.

The next step is a human pituitary, though the researchers say that’s still years away. But progress is progress. If you can build a trachea and a retina and a pillar of the endocrine system in a lab, the list of things you can’t build begins to narrow.

Source: Popular Science

 
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14/01/2018 @ 16:07:36
By Napasechnik
Nice read, I just passed this onto a friend who was doing some research on that. And he just bought me lunch since I found it for him smile So let me rephrase that Thank you for lunch! Whenever you ha...
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