Best Possible Cut From Gemstones With New Machine

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ScienceDaily (June 26, 2009) — Emeralds, rubies and the likes are referred to as colored gemstones by experts. They sparkle and shine with varying intensity, depending on the cut. A new machine can achieve the best possible cut and extract up to 30 per cent more precious stone from the raw material.

“We were astounded when our customer, Markus Wild, approached us and we were not at all certain whether mathematics could offer a solution for the very complex problem of volume optimization of gemstones,” says Dr. Anton Winterfeld from the Fraunhofer Institute for Industrial Mathematics ITWM. Jointly with his colleague Dr. Peter Klein, he will receive one of the 2009 Joseph von Fraunhofer prizes for the development of GemOpt, a new industrial process for the volume-optimized utilization of colored gemstones.
In contrast to diamonds, there are innumerable combinations of types and proportions of cut, and types of facet patterns for colored gemstones. When chosen correctly, the interplay of these variables ensures the luster in the stone, its shine. Sometimes just a few facets are sufficient to make a gemstone sparkle, sometimes several hundred. The task was to set limits on what seemed to be infinite and to calculate the optimal volume. The mathematical approach, which finally resulted in a solution, originated from the area of general semi-infinite optimization.
This involved a new type of algorithm, which had until now only been theoretically defined. The team at the ITWM continued to develop this approach and implemented it for this specific problem. The result is an outstanding achievement, also in scientific terms. The second essential part of GemOpt is process control, which Dr. Peter Klein has worked out. For this he ascertained precisely how raw gemstones behave when processed and transferred his findings to the control unit of the machine.
The machine runs fully automatically. First of all, the raw stone is measured. On the basis of these data, the computer calculates optimal embedments, proportions and facet patterns for different basic geometries. The customer then opts for one of the proposed solutions and the machine begins cutting. The process control unit is finely balanced, so that the machine does not split the stones as it cuts them.
The system then moves seamlessly on to the polishing step. The 17 axes ensure that the stone can move along any desired path. The machine cuts the facets to ten micrometers exactly – the stones are therefore perfectly geometric. A further advantage is that the machine can produce identical stones – ideal for necklaces. Cutting with the machine can result in up to 30 per cent more weight. This puts a significantly higher price on the stone.
Adapted from materials provided by Fraunhofer-Gesellschaft.

Acoustic Sensor Being Developed In New Anechoic Chamber

Source:

http://www.sciencedaily.com/releases/2007/10/071030103916.htm

ScienceDaily (Nov. 4, 2007) — The University of Alabama College of Engineering is developing a new acoustic sensor to be tested in UA’s new hemi-anechoic chamber. This new sensor could one day be used to help locate individuals trapped in collapsed buildings, such as after natural or man-made disasters.

Typically, multiple microphones are used to measure the location of an acoustic source, but this project is aimed at developing a single sensor that performs the same task. Its applications will be useful in aiding the military, homeland security and emergency rescue efforts.
“It’s exciting to work on a project that could dramatically change the effectiveness of emergency response teams,” said Dr. Steve Shepard, associate professor in mechanical engineering. “For instance, if a building collapses, our sensor could locate the noises made by victims trapped under debris and help rescue those victims more quickly. The sensor could also be used for security purposes, such as monitoring the location and motion of vehicles.”
Once a prototype is developed, the sensor will be tested in UA’s new hemi-anechoic chamber, which is one of the largest in the Southeast. The chamber is a room that is isolated from external sounds. The walls and ceiling are covered with a very-thick, foam-like material that eliminates all acoustic reflections. Shepard stated that being in the chamber is, “like standing in a very large quiet field. You can almost hear your own heartbeat.” This isolation allows for detailed acoustic measurements on a wide range of structures.
Visually, the chamber resembles a high-tech recording studio. The chamber walls are covered by 2-foot thick, gray, triangular-shaped foam wedges. The 8-inch thick metal walls are filled with insulation made from recycled denim material. Additionally, the entire chamber and the supporting concrete floor, all 150,000 pounds, float on springs to prevent outside vibrations from interfering with acoustic testing. The entire chamber is located in the AIME Building, which has 18-inch thick exterior concrete walls, another sound barrier.
“This chamber gives UA unique acoustic testing capabilities that most research organizations simply don’t have,” said Shepard. “This is true particularly when it comes to testing large machines, structures, and even automobiles. We can now take acoustic measurements on a machine and not worry about the effects of reflections or outside noise. Our ability to better understand how that machine radiates noise – and develop ways to make it quieter – has been greatly extended.”
Shepard said there are several areas researchers hope to explore, including:
reducing noise through powered systems and soundproofing
health monitoring of machines
heating and air conditioning system components
Gear, bearings, motor and engine noise
Consumer product noise and vibration
Shepard was awarded the $120,000 grant from the National Science Foundation to develop the new sensor. UA’s College of Engineering is partnering with Tuskegee University, where researchers received an additional $100,000 grant for their contribution to this research project. Throughout the project, UA and Tuskegee faculty and students will have an opportunity to use the chamber to evaluate prototypes for the acoustic sensor.
Adapted from materials provided by University of Alabama.

Fausto Intilla

www.oloscience.com

Hydrogen Storage Model Speeds Development Of Alternative Fuel Vehicles

Source:

http://www.sciencedaily.com/releases/2007/10/071003100601.htm

Science Daily — Researchers at the UCLA Henry Samueli School of Engineering and Applied Science have developed a model that could help engineers and scientists speed up the development of hydrogen-fueled vehicles by identifying promising hydrogen-storage materials and predicting favored thermodynamic chemical reactions through which hydrogen can be reversibly stored and extracted.
Because of global environmental changes associated with man-made carbon dioxide emissions and the limited resources of fossil fuels, developing alternate and renewable energy sources is important for a sustainable future. Hydrogen is a potential source of clean energy for future use in passenger vehicles powered by cheap and energy-efficient fuel cells, but its widespread adoption has been hindered by the need to store it on-board at very high densities.
A promising solution to this problem involves storing hydrogen within a material in the form of a chemically bound hydride, for example lithium hydride (LiH). Unfortunately, simple binary hydrides, in which hydrogen combines with light elements such as lithium, sodium, magnesium or others, do not adequately satisfy the requirements for on-board storage, as the hydrogen-yielding reaction requires heating the material to impractically high temperatures.
Because of this, researchers have turned to multicomponent hydride mixtures with higher volumetric and gravimetric densities, better operating temperatures and improved reaction rates for practical hydrogen storage. However, this flexibility comes at the price of drastically increased complexity associated with the large number of competing reactions and possible end-products other than hydrogen.
Thus, predicting desirable hydrogen storage with multicomponent mixtures has proved difficult. For example, the recently studied lithium hydride compound Li4BN3H10 was found to have as many as 17 hydrogen-release reactions, of which only three were found to be feasible — and none were in the desired range of temperatures and hydrogen pressures for practical on-board storage in hydrogen-powered vehicles.
The research team used modern quantum mechanical theories and high-powered computers to develop an algorithm that can automatically and systematically pinpoint phases and reactions that have the most favored thermodynamic properties — that is, those that can release hydrogen at ambient temperatures using the waste heat from a proton exchange membrane (PEM) fuel cell. The team tested the method on the well-studied Lithium-Magnesium-Nitrogen-Hydrogen system, predicting all experimentally observed pathways in the system. The researchers say this method can also be applied to other multicomponent hydrogen systems.
The new method, published in Advanced Materials, was developed by Alireza Akbarzadeh, a UCLA postdoctoral researcher in the department of materials science and engineering; Vidvuds Ozolins, UCLA associate professor of materials science and engineering; and Christopher Wolverton, professor of materials science and engineering at Northwestern University in Illinois.
"The development of an algorithm that goes beyond chemical intuition and finds all hydrogen storage reactions 'in silico' is crucial and will help the scientific and engineering community to develop revolutionary new hydrogen-storage materials," Akbarzadeh said. "This is a major achievement in the field, which can boost up the search for the best reversible solid-state hydrogen storage."
"We are steadily approaching the moment when we will be able to theoretically design materials with desired properties, just like a tailor makes a suit to fit the customer's needs," Ozolins said. "This will bring in a qualitatively new era of collaboration between theory and computation, experiment and technology development."
The research was funded by grants from the U.S. Department of Energy.
Note: This story has been adapted from material provided by University of California, Los Angeles.

Fausto Intilla
www.oloscience.com

New Material For Aircraft Wings Could Save Billions

Source:

http://www.sciencedaily.com/releases/2007/09/070926094727.htm

Science Daily — Building aircraft wings with a special aluminium fibre combination makes them nearly immune to metal fatigue. The application of this technology, partly developed at Delft University of Technology, will lead to substantial savings.

The unusual qualities of this special material (called CentrAl, an abbreviation of Central Reinforced Aluminium) can make a significant contribution to the development of truly energy-efficient, 'green' aircraft. Lower fuel consumption and reduction of maintenance costs could lead to worldwide savings as high as $100 billion.
Fatigue is a phenomenon that affects materials after long-term exposure to cyclic loading. As a result of varying loads, fractures eventually occur. The new, high-quality CentrAl aluminium constructions are stronger than the carbon fibre reinforced plastic (CFRP) constructions that have recently been used in aircraft wings such as the Boeing 787. By using CentrAl wing constructions, the weight can be reduced by another 20 per cent compared to CFRP constructions. Furthermore, using CentrAl results in considerably lower manufacturing and maintenance costs.
The CentrAl concept comprises a central layer of fibre metal laminate (FML), sandwiched between one or more thick layers of high-quality aluminium. This creates a robust construction material which is not only exceptionally strong, but also insensitive to fatigue. The CentrAl technique allows for simple repairs to be carried out immediately, as is the case in aluminium constructions, -- but not the case when using CFRP constructions.
This patented new concept is one of the results of an intensive collaboration between the company GTM Advanced Structures, founded in The Hague in 2004 and specialising in new aircraft materials and constructions, the American aluminium company Alcoa, and the Faculty of Aerospace Engineering of Delft University of Technology.
During a conference in Delft (Conference on Damage Tolerance of Aircraft Structures: 25-28 September 2007), GTM and Alcoa have presented the new concept to international experts in the field of metal fatigue and damage sensitivity of aircraft constructions. The US Air Force, Alcoa and GTM will also shed new light on the fact that the new CentrAl materials create possibilities for so-called 'Carefree structures'.
These are aircraft constructions that are less sensitive to damage caused, for example, by fatigue, hail storms, other weather phenomena, trucks that collide with the aircraft and corrosion. Carefree aircraft constructions will be characterised by significantly reduced maintenance costs.
Note: This story has been adapted from a news release issued by Delft University of Technology.

Fausto Intilla

www.oloscience.com