Автор: Пользователь скрыл имя, 28 Мая 2011 в 22:43, реферат
The future of the material sciences is closely linked to nanotechnology. And Nanotechnology engineering is a multi-disciplinary engineering field, which draws from and benefits areas such as materials science and engineering, chemistry, physics, biology, and medicine. The purpose of this presentation is to tell about nanotechnology applications in these fields.
Nanotechnology Applications
The future of the material sciences is closely linked to nanotechnology. And Nanotechnology engineering is a multi-disciplinary engineering field, which draws from and benefits areas such as materials science and engineering, chemistry, physics, biology, and medicine. The purpose of this presentation is to tell about nanotechnology applications in these fields.
Nanotechnology is defined as the study and use of structures between 1 nanometer and 100 nanometers in size. To give you an idea of how small that is, it would take eight hundred 100 nanometer particles side by side to match the width of a human hair.
Four Generations
Mihail (Mike) Roco has described four generations of nanotechnology development (see chart below). The current era, as Roco depicts it, is that of passive nanostructures, materials designed to perform one task. The second phase introduces active nanostructures for multitasking; for example, actuators, drug delivery devices, and sensors. The third generation, which we are just entering, is feature nanosystems with thousands of interacting components. A few years after that, the first integrated nanosystems are expected to be developed.
The ability to see nano-sized materials has opened up a world of possibilities in a variety of industries and scientific endeavors. Because nanotechnology is essentially a set of techniques that allow manipulation of properties at a very small scale, it can have many applications, such as the ones listed below.
The use of nanotechnology in medicine offers some exciting possibilities. Some techniques are only imagined, while others are at various stages of testing, or actually being used today.
Nanotechnology in medicine involves applications of nanoparticles currently under development, as well as longer range research that involves the use of manufactured nano-robots to make repairs at the cellular level (sometimes referred to as nanomedicine).
|
Nanotechnology in Electronics (Nanoelectronics)
How can nanotechnology improve the capabilities of electronic components?
Nanoelectronics holds some answers for how we might increase the capabilities of electronics devices while we reduce their weight and power consumption. Some of the nanoelectronics areas under development, which you can explore in more detail by following the links provided in the next section, include the following topics.
Improving display screens on electronics devices. This involves reducing power consumption while decreasing the weight and thickness of the screens.
Increasing the density of memory chips. Researchers are developing a type of memory chip with a projected density of one terabyte of memory per square inch or greater.
Reducing the size of transistors used in integrated circuits. One researcher believes it may be possible to "put the power of all of today's present computers in the palm of your hand".
Nanoelectronics: Company Directory
|
Nanotechnology is being used in several applications to improve the environment. This includes cleaning up existing pollution, improving manufacturing methods to reduce the generation of new pollution, and making alternative energy sources more cost effective.
There are two major ways in which nanotechnology is being used to reduce air pollution: catalysts, which are currently in use and constantly being improved upon; and nanostructured membranes, which are under development.
Water Pollution and Nanotechnology
How can nanotechnology be used to reduce water pollution?
Nanotechnology is being used to develop solutions to three very different problems in water quality.
One challenge is the removal of industrial water pollution from ground water. Nanoparticles can be used to convert the contaminating chemical through a chemical reaction to make it harmless.
Another challenge is the removal of salt or metals from water. A deionization method using electrodes composed of nano-sized fibers shows promise for reducing the cost and energy requirements of turning salt water into drinking water.
The third problem concerns the fact that standard filters do not work on virus cells. A filter only a few nanometers in diameter is currently being developed that should be capable of removing virus cells from water.
Nanotechnology may hold the key to making space flight more practical. Advancements in nanomaterials make lightweight solar sails and a cable for the space elevator possible. By significantly reducing the amount of rocket fuel required, these advances could lower the cost of reaching orbit and traveling in space. In addition, new materials combined with nanosensors and nanorobots could improve the performance of spaceships, spacesuits, and the equipment used to explore planets and moons, making nanotechnology an important part of the ‘final frontier.’
Researchers are looking into the following applications of nanotechnology in space flight:
Nanotechnology is having an impact on several aspects of food science, from how food is grown to how it is packaged. Companies are developing nanomaterials that will make a difference not only in the taste of food, but also in food safety, and the health benefits that food delivers.
|
Clay nanocomposites are being used to provide an impermeable barrier to gasses such as oxygen or carbon dioxide in lightweight bottles, cartons and packaging films.
Nanomer particles protruding from a plasma-etched polymer matrix
Storage bins are being produced with silver nanoparticles embedded in the plastic. The silver nanoparticles kill bacteria from any material that was previously stored in the bins, minimizing health risks from harmful bacteria.
Nanoparticles are being developed that will deliver vitamins or other nutrients in food and beverages without affecting the taste or appearance. These nanoparticles actually encapsulate the nutrients and carry them through the stomach into the bloodstream.
Researchers are using silicate nanoparticles to provide a barrier to gasses (for example oxygen), or moisture in a plastic film used for packaging. This could reduce the possibly of food spoiling or drying out.
Zinc oxide nanoparticles can be incorporated into plastic packaging to block UV rays and provide anti bacterial protection, while improving the strength and stability of the plastic film.
Nanosensors are being developed that can detect bacteria and other contaminates, such as salmonella, at a packaging plant. This will allow for frequent testing at a much lower cost than sending samples to a lab for analysis. This point-of-packaging testing, if conducted properly, has the potential to dramatically reduce the chance of contaminated food reaching grocery store shelves.
"Interactive" foods are being developed that would allow you to choose the desired flavor and color. Nanocapsules that contain flavor or color enhancers are embedded in the food; inert until a hungry consumer triggers them. The method hasn't been published, so it will be interesting to see how this particular trick is accomplished.
Researchers are also working on pesticides encapsulated in nanoparticles; that only release pesticide within an insect's stomach, minimizing the contamination of plants themselves.
Making composite fabric with nano-sized particles or fibers allows improvement of fabric properties without a significant increase in weight, thickness, or stiffness as might have been the case with previously-used techniques. For example incorporating nano-whiskers into fabric used to make pants produces a lightweight water and stain repellent material.
|