Abstract This paper explains that smart materials are devices, which can sense various stimuli from outer environment such as thermal, electrical and magnetic changes and can respond accordingly; basically, they are materials that sense and respond like living things. The author points out that two families of passive seismic control devices exploiting the peculiar properties of SMA kernel components have been implemented and tested within the MANSIDE project (Memory Alloys for New Seismic Isolation and Energy Dissipation Devices: Special braces for framed structures and isolation devices for buildings and bridges. The paper states that, with these smart materials, engineers are able to build the best and safest structures where possible catastrophic changes in the environment are sensed and precautions are taken directly. 10 figures.
Table of Contents
Introduction
What is a Smart Material?
Types of Smart Materials
Classification Based on Input
Electrical Fields
Thermal Fields
Magnetic Fields
Comparison Based on Output
Strain
Changes in Other Properties
Applications
In Civil Engineering
Uses of Shape Memory Alloys Smart Concrete
In Other Areas
Conclusion
From the Paper "The first experimental demonstration of the piezoelectric properties in relation to crystal structure was published in 1880 by Pierre and Jacques Curie. This effect was considered quite important and was referred to as "piezoelectricity" in order to distinguish it from other areas of scientific phenomenological experience such as "pyroelectricity" (electricity generated from crystals by heating). As an aside, piezoelectrics also tend to be pyroelectrics. The Curie brothers did not predict that crystals exhibiting the direct piezoelectric effect (electricity from applied stress) would also exhibit the converse piezoelectric effect (stress in response to applied electric field). This property was mathematically deduced and hypothesized by Lippmann in 1881. The Curies then confirmed the existence of the converse effect, and continued on to obtain quantitative proof of the complete reversibility of mechanical deformations in piezoelectric crystals."
Abstract This paper provides an insight into brass, a useful alloy of two metals, copper and zinc which has been used for cultural uses and ornamentation since the 13th century BC. It examines how the porosity, or the ratio of the volume of interstices of a material to the volume of its mass, can be reduced in order for brasses of all compositions to be worked or hardened to form wires, fittings or ornaments with the most utilitarian strength, elasticity or ductility features.
Outline
Introduction
Brass
A Thousand Years of Brass-Making
Phase Diagram for All Brasses
Density of Brass Varieties
Porosity in Brass
Metal Porosity--in its Place
Manufacturing Methods to Reduce Porosity
Post-Manufacturing Methods that May Reduce Porosity
Unavoidable Internal Change Mechanisms Possibly Affecting Porosity
Summary and Conclusions
From the Paper "As with many metals and alloys, brass is often worked after its formation, not merely for shaping into the desired form, but also to alter for improvement one or more of its physical properties: Strength or hardness, ductility or elasticity, as examples. The methods are generally lumped as a number of "hardening" types, although their purposes rarely include the reduction of porosity, per se. Some are carried out at room temperature (called "cold work"); others are performed at a variety of elevated temperatures, each having its own intended effect (called "hot working")(14:7-9)."
Abstract This paper discusses different surface modifications, which improve their osseointegration. The author points out methods of applying coatings. The paper explores cell proliferation on these implant surface and what affects the process.
From the Paper "It was not until materials became available that promoted an osseointegrated or bio-integrated interface and surgical techniques were developed to reliably obtain such interfaces that endosseous implants became a viable treatment option for tooth replacement. Commercially-pure titanium is actually an alloy containing wt percent titanium and small amounts wt ... percent to wt .. percent of oxygen with trace amounts less than percent of iron carbon nitrogen and hydrogen. The amount of oxygen determines the grade of the alloy Increasing amounts of oxygen increase the
A highly technical paper that reviews literature on the operating procedure and magnetic properties of electrochemical deposited Co-based magnetic films.
2,057 words (approx. 8.2 pages), 13 sources, 2001, $ 64.95
Abstract This report reviews literature on the operating procedure and magnetic properties of electrochemical deposited Co-based magnetic films. The significance and limitations of electrochemical deposit Co-based magnetic films are analyzed.
From the Paper " Hard magnetic materials have been a focus of interest in electrical engineering for years because of their applications as media in recording and potential applications in fabricating magnetic MEMS devices due to the strong magnetic field produced by them in absence of applying magnetic field1.2. Besides the hard ferrites and Nd2Fe14 B1, Cobalt or Cobalt-RE based magnets are mostly used hard magnetic materials because of their good magnetic properties as well as their excellent mechanical properties1. Generally speaking, Cobalt based hard magnetic materials are fabricated by PVD methods such as RF sputtering or evaporation. However, it is likely to be time and money consuming to apply these procedures, especially for a relatively thick film, say, 20mm or more, is needed. Furthermore, the fabrication of the film-type magnets on silicon wafers with CMOS integrated circuits has been considered as one of the most extremely difficult tasks due to the fabrication processing incompatibility between them."
Abstract This paper examines all things related to the atomic element titanium. The author describes its properties, color, appearance, from where it can be mined and the discovery of the element. The paper also discusses commercial extraction and the various uses for titanium.
From the Paper "Titanium is not commonly used because it is among the most difficult of all metals to obtain in pure form. It has high reactivity with carbon, nitrogen, and oxygen at high temperatures, which means that it cannot be extracted from its ores using the types of process commonly used for other metals. Although titanium compounds have been known since 1795, it was not until 1910 that the New Zealand-born metallurgist Matthew Hunter, working in the United States, produced the first pure sample of the metal."
Abstract This paper provides an application oriented state-of-the-art review of smart materials and magnetostrictive actuators in aeronautical design. Smartness describes self-adaptability, self-sensing, memory and multiple functionality of the materials or structures. The paper shows that these characteristics provide numerous possible applications for these materials and structures in aerospace, manufacturing, civil infrastructure systems and biomechanics. Active vibration and acoustic transmission control, active shape control and active damage control are some of those areas which have found attractive applications for smart materials and structures. Examples of specific applications are micro-positioning, vibration isolation, fast acting valve and nozzles, transducers, luxury car shocks, and active engine mounts in aircrafts. The paper shows that system integration, mass and energy consumption reduction, elimination of moving parts in actuators and collocation between actuator and sensor are some of the benefits of using smart materials. Those smart materials covered in this paper are primarily piezoelectric, shape memory alloys and magnetostrictive.
From the Paper "Along these lines there is growing interest in the design and control of smart structures systems with embedded sensors and actuators that provide enhanced ability to program a desired response from a system. The ability to sense real-time conditions, i.e., the factors that contribute to turbulence and therefore resistance in a given environment, would be welcome and useful. Applications of interest include: (a) smart helicopter rotors with actuated flaps that alter the aerodynamic and vibrational properties of the rotor in conjunction with evolving flight conditions and aerodynamic loads; and (b) smart fixed wings with actuators that alter airfoil shape to accommodate changing drag/lift conditions. In these and other examples, key technologies include actuators based on materials that respond to changing electric, magnetic, and thermal fields via piezoelectric, magnetostrictive and thermo-elasto-plastic interactions."
Abstract This paper discusses one of the most important and nation altering events to occur in the 1960s, the Apollo astronaut program, specifically, Neil Armstrong and Buzz Aldren's successful walk on the moon on July 20, 1969. It analyzes how space flight stimulated the nation's growth in myriad ways. It looks at the many technological advances came from the Mercury and Apollo programs and beyond, from lightweight metal alloys to smaller and smaller computer guidance systems which eventually turned into desktop computers so extremely prevalent in the world today. It evaluates how if we had not gone to the moon, our lives today might be much different and so would many of our institutions. Space flight stimulated technological growth, national pride and the notion that we can still "reach for the stars."
From the Paper "First came the Mercury project, where America put men in space. On May 5, 1961, Major Alan Shepard, a Naval academy graduate and test pilot, climbed aboard the Freedom 7 capsule atop a Redstone rocket and became the first American in space. Shepard's flight was sub orbital and lasted only 15 minutes, but it showed America we could still be vital in the space race (which the Russians were winning at the moment), and it kindled spirit and passion in the minds of Americans. The Mercury program ran from 1958 to 1963, and satisfied all its objectives. The Gemini flights between 1965 and 1966 were designed to transition between the Mercury exercises and the Apollo moon missions. The Gemini flights were to teach us how maneuver a spacecraft by maneuvering it in orbit, rendezvousing in space, docking with other vehicles, perfecting methods of entering the atmosphere, and landing at a preselected point on land."
