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Already, endometrial-containing products are available in U. S. Markets including coatings, computers, clothing, cosmetics, sports equipment and medical devices. A survey by Emmett Research of companies working In the field of nanotechnology has identified approximately 80 consumer products, and over 600 awe materials, intermediate components and industrial equipment items that are used by manufacturers (Small Times Media, 2005).
A second survey by the Project on Emerging Nanotechnology at the Woodrow Wilson International Center for Scholars lists over 300 consumer products (http://www. Anthropometric. Org/index. PH? Id=44 or http://www. Nanotechnology]etc. Org/conductresses). Our economy will be increasingly affected by nanotechnology as more products containing endometrial move from research and development into production and commerce.
Nanotechnology also has the potential to improve the environment, both through erect applications of endometrial to detect, prevent, and remove pollutants, as well as indirectly by using nanotechnology to design cleaner industrial processes and create environmentally responsible products. However, there are unanswered questions about the Impacts of endometrial and unprocessed on human health and the environment, and the u. s. Environmental Protection Agency (EPA or “the Agency”) has the obligation to ensure that potential risks are adequately understood to protect human health and the environment.
As products made from endometrial become more numerous and therefore more prevalent in the environment, EPA is thus considering how to best leverage advances In nanotechnology to enhance environmental protection, as well as how the Introduction of endometrial Into the environment will Impact the Agency environmental programs, policies, research needs, and approaches to decision making. REVIEW OF RELATED LITERATURE A nanometer is one billionth of a meter (10-9)-??about one hundred thousand times smaller than the diameter of a human hair, a thousand times smaller than a red blood cell, or about half the size of the diameter of DNA.
Figure 1 illustrates the scale of objects in the nanometer range. For the purpose of this document, nanotechnology is defined as: research and technology development at the atomic, molecular, or macromolecular levels using a length scale of approximately one to one hundred manometers in any dimension; the creation and use of structures, devices and systems that have novel properties and functions because of their small size; and the ability to control or manipulate matter on an atomic scale. This definition is based on part on the definition of nanotechnology used by the National Nanotechnology Initiative (IN), a U.
S. Government initiative launched in 2001 to ordinate nanotechnology research and development across the federal government (IN, AAA, b, c). Nanotechnology is the manipulation of matter for use in particular applications through certain chemical and or physical processes to create materials with specific properties. There are both “bottom-up” processes (such as self-assembly) that create annoyance materials from atoms and molecules, as well as “top-down” processes (such as milling) that create annoyance materials from their macro-scale counterparts.
Annoyance materials that have macro-scale counterparts frequently display different or enhanced properties compared to the agro-scale form. For the remainder of this document such engineered or manufactured endometrial will be referred to as “intentionally produced endometrial,” or simply “endometrial. ” The definition of nanotechnology does not include unintentionally produced endometrial, such as diesel exhaust particles or other friction or airborne combustion byproducts, or unionized materials that occur naturally in the environment, such as viruses or volcanic ash.
Where information from incidentally formed or natural unionized materials (such as ultramarine particulate matter) may aid in the understanding of intentionally produced materials, this information will be discussed, but the focus of this document is on intentionally produced endometrial. Carbon-based materials. These endometrial are composed mostly of carbon, most commonly taking the form of a hollow spheres, ellipsoids, or tubes. Spherical and ellipsoidal carbon endometrial are referred to as fullness, while cylindrical ones are called annotates.
These particles have many potential applications, including improved films and coatings, stronger and lighter materials, and applications in electronics. Metal-based materials. These endometrial include quantum dots, Angola, noisier and metal oxides, such as titanium dioxide. A quantum dot is a closely packed semiconductor crystal comprised of hundreds or thousands of atoms, and whose size is on the order of a few manometers to a few hundred manometers. Changing the size of quantum dots changes their optical properties. Dendrites. These endometrial are unionized polymers built from branched units.
The surface of a dendrite has numerous chain ends, which can be tailored to perform specific chemical functions. This property could also be useful for catalysis. Also, because tatterdemalion’s dendrites contain interior cavities into wows an example a dendrite. Composites combine inappropriate with other inappropriate or with larger, bulk- type materials. Inappropriate, such as unionized clays, are already being added to products ranging from auto parts to packaging materials, to enhance mechanical, thermal, barrier, and flame-retardant properties.
The unique properties of these various types of intentionally produced endometrial give them novel electrical, catalytic, magnetic, mechanical, thermal, or imaging features that are highly desirable for applications in commercial, medical, military, and environmental sectors. As new uses for materials with these special properties are identified, the number of products containing such endometrial and their possible applications continues to grow.
Nanotechnology is very diverse, ranging from extensions of conventional device physics to completely new approaches based upon molecular self-assembly, from developing new materials with dimensions on the annoyance to direct control of matter on the atomic scale. Nanotechnology entails the application of fields of science as diverse as surface science, organic chemistry, molecular biology, semiconductor physics, corroboration, etc. Scientists debate the future implications of nanotechnology.
Nanotechnology may be able to create many new materials and devices with a vast range of applications, such as in medicine, electronics, biometrics and energy production. On the other hand, nanotechnology raises many of the same issues as any new technology, including concerns about the toxicity and environmental impact of endometrial, and their potential effects on global economics, as well as speculation about various doomsday scenarios. These concerns have led to a debate among advocacy groups ND governments on whether special regulation of nanotechnology is warranted.
Origins of Nanotechnology Although nanotechnology is a relatively recent development in scientific research, the development of its central concepts happened over a longer period of time. The emergence of nanotechnology in the sass was caused by the convergence of experimental advances such as the invention of the scanning tunneling microscope in 1981 and the discovery of fullness in 1985, with the elucidation and popularization of a conceptual framework for the goals of nanotechnology beginning tit the 1986 publication of the book Engines of Creation.
The scanning tunneling microscope, an instrument for imaging surfaces at the atomic level, was developed in 1981 by Gear Binning and Heimlich Rorer at IBM Zurich Research Laboratory, for which they received the Nobel Prize in Physics in 1986. Fullness were discovered in 1985 by Harry Grotto, Richard Smaller, and Robert Curl, who together won the 1996 Nobel Prize in Chemistry. Around the same time, K. Eric Drexel developed and popularized the concept of nanotechnology and founded the field of molecular nanotechnology. In 1979, Drexel encountered Richard Funnyman’s 1959 talk “There’s Plenty of Room at the Bottom”. Unknowingly appropriated by Drexel in his 1986 book Engines of Creation: The Coming Era of Nanotechnology, which proposed the idea of a annoyance “assembler” which would be able to build a copy of itself and of other items of arbitrary complexity. He also first published the term “grey go” to describe what might happen if a hypothetical self-replicating molecular nanotechnology went out of control. Dresser’s vision of nanotechnology is often called “Molecular Nanotechnology” (MET) or “molecular manufacturing,” and Drexel at one point reposed the term “catheter” which never became popular.
In the early sass, the field was subject to growing public awareness and controversy, with prominent debates about both its potential implications, exemplified by the Royal Society’s report on nanotechnology, as well as the feasibility of the applications envisioned by advocates of molecular nanotechnology, which culminated in the public debate between Eric Drexel and Richard Smaller in 2001 and 2003. Governments moved to promote and fund research into nanotechnology with programs such as the National Nanotechnology Initiative.
The early sass also saw the beginnings of commercial applications of nanotechnology, although these were limited to bulk applications of endometrial, such as the Silver Anna platform for using silver inappropriate as an antibacterial agent, nonpolitical-based transparent sunscreens, and carbon annotates for stain- resistant textiles. Fundamental Concepts Underlying Annotate Nanotechnology is the engineering of functional systems at the molecular scale. This covers both current work and concepts that are more advanced.
In its original sense, nanotechnology refers to the projected ability to construct items from the OTTOMH up, using techniques and tools being developed today to make complete, high performance products. One nanometer (NM) is one billionth, or 10-9, of a meter. By comparison, typical carbon-carbon bond lengths, or the spacing between these atoms in a molecule, are in the range NM, and a DNA double-helix has a diameter around 2 NM. On the other hand, the smallest cellular life-forms, the bacteria of the genus Macrocosms, are around 200 NM in length.
By convention, nanotechnology is taken as the scale range 1 to 100 NM following the definition used by the National Nanotechnology Initiative in the US. The lower limit is set by the size of atoms (hydrogen has the smallest atoms, which are approximately a quarter of a NM diameter) since nanotechnology must build its devices from atoms and molecules. The upper limit is more or less arbitrary but is around the size that phenomena not observed in larger structures start to become apparent and can be made use of in the Anna device.
These new phenomena make nanotechnology distinct from devices which are merely miniaturized versions of an equivalent macroscopic device; such devices are on a larger scale and come under the description of microelectronic. To put that scale in another context, the comparative size of a nanometer to a meter is the same as that of a marble to the size of the earth. Or another way of putting it: a nanometer is the amount an average man’s beard grows in the time it Two main approaches are used in nanotechnology.
In the “bottom-up” approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the “top-down” approach, Anna-objects are constructed from larger entities without atomic-level control. Areas of physics such as maledictions, mechanicals, monophonic and nonionic have evolved during the last few decades to provide a basic scientific foundation of nanotechnology. Larger to Smaller: A Materials Perspective. Several phenomena become pronounced as the size of the system decreases.
These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, quantum effects become dominant when the nanometer size range is reached, typically at distances of 100 manometers or less, the so-called quantum realm. Additionally, a number of physical (mechanical, electrical, optical, etc. Properties change when compared to macroscopic systems. One example is the increase in surface area to volume ratio altering mechanical, thermal and catalytic properties of materials. Diffusion and reactions at annoyance, unstructured materials and indecisive with fast ion transport are generally referred to nonionic. Mechanical properties of monoester are of interest in the mechanics research. The catalytic activity of endometrial also opens potential risks in their interaction with biometrics.
Materials reduced to the annoyance can show different properties compared to what they exhibit on a microscope, enabling unique applications. For instance, opaque substances become transparent (copper); stable materials turn combustible (aluminum); insoluble materials become soluble (gold). A material such as gold, which is chemically inert at normal scales, can serve as a potent chemical catalyst at nacelles. Much of the fascination with nanotechnology stems from these quantum ND surface phenomena that matter exhibits at the annoyance.
Simple to Complex: A Molecular Perspective. Modern synthetic chemistry has reached the point where it is possible to prepare small molecules to almost any structure. These methods are used today to manufacture a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. This ability raises the question of extending this kind of control to the next-larger level, seeking methods to assemble these single molecules into spectacular assemblies consisting of many molecules arranged in a well defined manner.
These approaches utilize the concepts of molecular self-assembly and or spectacular chemistry to automatically arrange themselves into some useful conformation through a bottom-up approach. The concept of molecular recognition is especially important: molecules can be designed so that a specific configuration or arrangement is favored due to non-covalent intermolecular forces. The Watson-Crick targeted to a single substrate, or the specific folding of the protein itself. Thus, two or more components can be designed to be complementary and mutually attractive so that they make a more complex and useful whole.
Such bottom-up approaches should be capable of producing devices in parallel and be much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases. Most useful structures require complex and thermodynamically unlikely arrangements of atoms. Nevertheless, there are many examples of self-assembly based on molecular recognition in biology, most notably Watson-Crick base pairing and enzyme-substrate interactions. The challenge for nanotechnology is whether these principles can be used to engineer new constructs in addition to natural ones.
Molecular Nanotechnology: A Long-term View Molecular nanotechnology, sometimes called molecular manufacturing, describes engineered monoester (annoyance machines) operating on the molecular scale. Molecular nanotechnology is especially associated with the molecular assembler, a machine that can produce a desired structure or device atom-by-atom using the principles of mechanistically. Manufacturing in the context of productive monoester is not related to, and should be clearly distinguished from, the conventional technologies used to manufacture endometrial such as carbon annotates and inappropriate.
When the term “nanotechnology” was independently coined and popularized by Eric Drexel (who at the time was unaware of an earlier usage by Nor Attaining) it referred to a future manufacturing technology based on molecular machine systems. The premise was that molecular scale biological analogies of traditional machine components demonstrated molecular machines were possible: by the countless examples found in biology, it is known that sophisticated, stochastically optimized biological machines can be produced.
It is hoped that developments in nanotechnology will make possible their instruction by some other means, perhaps using biometric principles. However, Drexel and other researchers have proposed that advanced nanotechnology, although perhaps initially implemented by biometric means, ultimately could be based on mechanical engineering principles, namely, a manufacturing technology based on the mechanical functionality of these components (such as gears, bearings, motors, and structural members) that would enable programmable, positional assembly to atomic specification.
The physics and engineering performance of exemplar designs were analyzed in Dresser’s book Monoester. In general it is very difficult to assemble devices on the atomic scale, as all one has to position atoms on other atoms of comparable size and stickiness. Another view, put forth by Carlo Montenegro, is that future monoester will be hybrids of silicon technology and biological molecular machines. Yet another view, put forward by the late Richard Smaller, is that mechanistically is impossible due to the difficulties in mechanically manipulating individual molecules.
This led to an exchange of letters in the ACS publication Chemical & Engineering are possible, non-biological molecular machines are today only in their infancy. Leaders in research on non-biological molecular machines are Dry. Alex Settle and his colleagues at Lawrence Berkeley Laboratories and US Berkeley. They have constructed at least three distinct molecular devices whose motion is controlled from the desktop with changing voltage: a annotate annotator, a molecular actuator, and a multimillionaire’s relaxation oscillator. Current Research Endometrial.
The endometrial field includes subfields which develop or study materials having unique properties arising from their annoyance dimensions. [24] Interface and colloid science has given rise to many materials which may be useful in nanotechnology, such as carbon annotates and other fullness, and various inappropriate and narrows. Endometrial with fast ion transport are related also to nonionic and maledictions. Annoyance materials can also be used for bulk applications; most present commercial applications of nanotechnology are of this flavor. Progress has been made in using these materials for medical applications; commandeering. 0 Annoyance materials are sometimes used in solar cells which combats the cost of traditional Silicon solar cells 0 Development of applications incorporating semiconductor inappropriate to be used in the next generation of products, such as display technology, lighting, solar cells and biological imaging; see quantum dots. Bottom-up Approaches. These seek to arrange smaller components into more complex assemblies. DNA nanotechnology utilizes the specificity of Watson-Crick beggaring to construct well-defined structures out of DNA and other nucleic acids. 0 Approaches from the field of “classical” chemical synthesis (inorganic and organic synthesis) also aim at designing molecules with well-defined shape (e. G. Ibis- peptides[25]). More generally, molecular self-assembly seeks to use concepts of spectacular chemistry, and molecular recognition in particular, to cause single- molecule components to automatically arrange themselves into some useful conformation.
Atomic force microscope tips can be used as a annoyance “write head” to deposit a chemical upon a surface in a desired pattern in a process called dip pen monolithically. This technique fits into the larger subfield of monolithically. Top-down Approaches. These seek to create smaller devices by using larger ones to direct their assembly. 0 Many technologies that descended from conventional lid-state silicon methods for fabricating microprocessors are now capable of creating features smaller than 100 NM, falling under the definition of nanotechnology.
Giant misinterpretations-based hard drives already on the market fit this description,[26] as do atomic layer deposition (LAD) techniques. Peter Gar;never and Albert Fret received the Nobel Prize in Physics in 2007 for their discovery of Giant misinterpretations and contributions to the field of spittoons. [27] Solid-state techniques can also be used to create devices known uncharacteristically systems or MESS. Focused ion beams can directly remove material, or even deposit material when suitable pre-cursor gases are applied at the same time.
For example, this technique is used routinely to create sub-100 NM sections of material for analysis in Transmission electron microscopy. Atomic force microscope tips can be used as a annoyance “write head” to deposit a resist, which is then followed by an etching process to remove material in a top-down method. Functional Approaches. These seek to develop components of a desired functionality without regard to how they might be assembled. Molecular scale electronics seeks to develop molecules with useful electronic properties.
These could then be used as single-molecule components in a malediction device. [28] For an example see Rotarian. Synthetic chemical methods can also be used to create synthetic molecular motors, such as in a so-called anchor. Biometric Approaches. Bionics or biometry seeks to apply biological methods and systems found in nature, to the study and design of engineering systems and modern technology. Familiarization is one example of the systems studied. 0 Phonologically is the use of bimolecular for applications in nanotechnology, including use of viruses.
Nucleolus’s is a potential bulk-scale application. Speculative. These subfields seek to anticipate what inventions nanotechnology might yield, or attempt to propose an agenda along which inquiry might progress. These often take a big-picture view of nanotechnology, with more emphasis on its societal implications than the details of how such inventions could actually be created. Molecular nanotechnology is a proposed approach which involves manipulating single molecules in finely controlled, deterministic ways. This is more theoretical than the other subfields and is beyond current capabilities.
Narcotics centers on self-sufficient machines of some functionality operating at the annoyance. There are hopes for applying narrators in but it may not be easy to do such a thing because of several drawbacks of such devices. [33]Nevertheless, progress on innovative materials and methodologies has been demonstrated with some patents granted about new infrastructure devices for future commercial applications, which also progressively helps in the development towards narrators with the use of embedded nonprescription concepts. Productive monoester are “systems of monoester” which will be complex annoyances that produce atomically precise parts for other monoester, not necessarily using novel annoyance-emergent properties, but well-understood fundamentals of manufacturing. Because of the discrete (I. E. Atomic) nature of matter and the possibility of exponential growth, this stage is seen as the basis of another industrial revolution.
Mail Rococo, one of the architects of the Aqua’s National Nanotechnology Initiative, has proposed four states of nanotechnology that seem to parallel the technical progress of the Industrial Revolution, progressing from passive unstructured to active indecisive to complex machineries and ultimately to productive monoester. 0 Programmable matter seeks to design materials whose information science and materials science. Due to the popularity and media exposure of the term nanotechnology, the words pigeonholing and phenomenology have been coined in analogy to it, although these are only used rarely and informally.
Tools and Techniques There are several important modern developments. The atomic force microscope (FM) and the Scanning Tunneling Microscope (STEM) are two early versions of scanning probes that launched nanotechnology. There are other types of scanning probe microscopy, all flowing from the ideas of the significantly microscope developed by Marvin Minsk in 1961 and the scanning acoustic microscope (SAM) developed by Calvin Equate and coworkers in the sass, that made it possible to see structures at the annoyance.
The tip of a scanning probe can also be used to manipulate unstructured (a process called positional assembly). Feature-oriented scanning methodology suggested by Irrationals Lapin appears to be a promising way to implement these mummifications in automatic mode. However, this is still a slow process because f low scanning velocity of the microscope. Various techniques of monolithically such as optical lithography, X-ray lithography dip pen monolithically, electron beam lithography or important lithography were also developed.
Lithography is a top-down fabrication technique where a bulk material is reduced in size to annoyance pattern. Another group of nanotechnology techniques include those used for fabrication of annotates and narrowness, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, focused ion beam machining, important lithography, atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing did-block copolymers.
However, all of these techniques preceded the annotate era, and are extensions in the development of scientific advancements rather than techniques which were devised with the sole purpose of creating nanotechnology and which were results of nanotechnology research. The top-down approach anticipates indecisive that must be built piece by piece in stages, much as manufactured items are made. Scanning probe microscopy is an important technique both for characterization and synthesis of endometrial.
Atomic force microscopes and scanning tunneling microscopes can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example, feature-oriented scanning approach, atoms or molecules can be moved around on a surface with scanning probe microscopy techniques.
At present, it is expensive and time-consuming for mass production but very suitable for laboratory experimentation. In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include chemical synthesis, self-assembly and positional assembly. Dual popularization interferometer is one tool suitable for approach is molecular beam epitaph or EMBED. Researchers at Bell Telephone Laboratories like John R. Arthur. Alfred Y. Choc, and Art C.
Soared developed and implemented EMBED as a research tool in the late sass and sass. Samples made by EMBED were key to the discovery of the fractional quantum Hall effect for which the 1998 Nobel Prize in Physics was awarded. EMBED allows scientists to lay down atomically precise layers of atoms and, in the process, build up complex structures. Important for research on semiconductors, EMBED is also widely used to make samples and devices for the newly emerging field of spittoons.
However, new therapeutic products, based on responsive endometrial, such as the ultramontane, stress-sensitive Transmogrification’s, are under development and already approved for human use in some countries. Applications As of August 21, 2008, the Project on Emerging Nanotechnology estimates that over 800 manufacturer-identified annotate products are publicly available, with new nest hitting the market at a pace of 3-4 per week. The project lists all of the products in a publicly accessible online database.
Most applications are limited to the use of “first generation” passive endometrial which includes titanium dioxide in sunscreen, cosmetics, surface coatings, and some food products; Carbon allotrope’s used to produce gecko tape; silver in food packaging, clothing, disinfectants and household appliances; zinc oxide in sunscreens and cosmetics, surface coatings, paints and outdoor furniture varnishes; and cerium oxide as a fuel catalyst. [9] Further applications allow tennis balls to last longer, golf balls to fly straighter, and even bowling balls to become more durable and have a harder surface.
Trousers and socks have been infused with nanotechnology so that they will last longer and keep people cool in the summer. Bandages are being infused with silver inappropriate to heal cuts faster. Cars are being manufactured with endometrial so they may need fewer metals and less fuel to operate in the future. Video game consoles and personal computers may become cheaper, faster, and contain more memory thanks o nanotechnology. Nanotechnology may have the ability to make existing medical applications cheaper and easier to use in places like the general practitioner’s office and at home.