Nanoemulsions
Just as colloidal dispersions of solid nanoscale particulates have received considerable attention, colloidal dispersions of deformable nanodroplets — nanoemulsions — are beginning to receive significant attention.
Although many basic principles of emulsification are already known for isolated droplets in relatively mild shear flows, the new principles of emulsification that govern nanodroplet rupturing and coalescence in extreme shear at high ø are still being discovered.
Quantitative theoretical predictions of droplet size distributions that include the combination of these two effects are sorely needed. Once formed, nanoemulsions can be manipulated and controlled in very precise ways.
Ultracentrifugal fractionation provides model monodisperse dispersions of nanoscale droplets in the size range from roughly a = 10 to 100 nm.
Scanning Tunneling and Atomic Force Microscope
Atomic Force Microscope (AFM) was invented by Binnig and introduced in 1985 by Binnig, Quate and Gerber as an offshoot from the Scanning Tunneling Microscope (STM).
While the STM is an ingenious instrument, which has shattered many paradigms about how to access the world of single atoms, the actual device is quite simple and grants an instructive appreciation of the concepts of atomic-scale imaging.
The AFM is somewhat more complicated and the additional challenges faced by AFM show up clearly in a direct comparison. STM and AFM have stimulated a revolution in surface science.
These techniques can image the surface of many materials with atomic resolution and provide information about the structure and organization of atomic and molecular adsorbates on surfaces.
The tip and its associated force or field can also be used to manipulate atoms and molecules to form unique structures.
Nanomedicine
Burgeoning interest in the medical applications of nanotechnology has led to the emergence of a new field called nanomedicine. Most broadly, nanomedicine is the process of diagnosing, treating, and preventing disease and traumatic injury, of relieving pain, and of preserving and improving human health, using molecular tools and molecular knowledge of the human body.
It is most useful to regard the emerging field of nanomedicine as a set of three mutually overlapping and progressively more powerful technologies. First, in the relatively near term, nanomedicine can address many important medical problems by using nanoscale-structured materials with biological systems.
Nanostructured materials and devices hold great promise for advanced diagnostics and biosensors, targeted drug delivery and smart drugs, and immunoisolation therapies.
Nanosintering
Nanosintering is the sintering of nanometer size powders. For certain nanomaterial applications, sintering of powders while retaining grain sizes in the nanometer range becomes a critical processing step. Fully dense specimens with nanosize features are most important for structural, magnetic, electric or electronic applications.
The focus in the consolidation of out-of-equilibrium powders has been the retention of the metastable condition of the initial structures. The inevitable coarsening tendency and small specimen size produced by nanopowder densification generats at least some controversies on nanomaterial properties.
The sintering process of powder materials with particle in the nanometer range reveals thermodynamic and kinetic aspects of metastable powder densification, methods for full densification of metastable powders and their ability to maintain the metastability features. Specific features related to cold compaction, pore size, distribution, and their effects on sintering and grain coarsening, sintering mechanisms, and scaling laws are also applicable to nanopowder sintering.
Nanoengineering
Nanoengineering is based on fundamental theory, engineering practice, and leading-edge technologies in fabrication of nanoscale systems, subsystems, devices, and structures that have dimensions of nanometers.
Nanoengineering deals with devising (synthesis), design, analysis, and optimization of nanoscale structures, devices, and systems that exhibit and utilize novel physical (electro-magnetic, electromechanical, electrochemical, optical, etc.), chemical, electrochemical, and biological properties, phenomena, and effects that can be discovered, examined, and predicted by nanoscience (fundamental laws).
Using the pure sizing classification, the dimension of nanosystems and their components (nanostructures) is from 10-10 m (atom/molecule size) to 10-7 m, that is, from 0.1 to 100 nm. To fabricate nanostructures, nanotechnology is applied.
Nanostructures have been proposed as environmental cleaning agents, chemical detection agents, for the creation of biological (or artificial) organs, for the development of nanoelectronic mechanical systems (NEMS), and for the development of ultrafast, ultradense electrical and optical circuits.
Rapid Tooling
Rapid Tooling (RT) is an offshoot of Rapid Manufacturing (RM), which itself is the next stage of Rapid Prototyping (RP). RP offers tremendous flexibility in the design stage, and can satisfy the demand for parts by making tools, which can be used for mass production of the demanded parts. The role of RT starts here by the fabrication of such tools.
In the manufacture of tools, RT has found great success in some industries but many have found its application to be limited. As advances in machined tooling have driven out cost and time, RT’s advantages have lessened, and its limitations remain unchanged.
The most often used technologies for RT allow the production of tooling inserts in metal. However, secondary operations are also required to deliver the required accuracy and surface finish demanded of a tool.
When added to the process, RT often offers only a slight time and cost advantage over machined tooling.
From CRP Technology a new Aluminium Alloy. CRP 8601
CRP Technology has launched a brand new product on the market.
It is not a castable product.
This material may successfully overcome high performance aluminium alloys such as: 7075, 7050, 2014, 2024, 2618, and others.
F1 industry uses MMC materials (i.e. AMC 225xe) while Super Aluminium materials, and therefore the new CRP 8601 alloy, are particularly suited for all the other motorsport racing series and for the aerospace sector.
The key benefits of CRP 8601 for structural applications include:
- Weight saving
- Increased component stiffness
- High fatigue resistance
- Good hardness & wear resistance
- High flexibility of the billets shapes/dimensions for machining
Tissue Engineering and Nanoengineering
Due to the combined efforts of basic and material scientists, cell biologists, engineers, and clinicians, the field of tissue engineering has now developed into a highly interdisciplinary science and has attempted to recreate or regenerate almost every type of human tissue and organ.
Tissue engineering is now the application of biological, chemical and engineering principles towards the repair, restoration or regeneration of living tissues using biomaterials, cells and factors, alone or in combination. Biodegradable porous three-dimensional (3D) structures have been extensively used as scaffolds for tissue engineering to temporarily mimic the structure and functions of the natural extracellular matrix (ECM).
The ECM functions to provide 3D structure with mechanical and biochemical cues to support and control cell organization and functions.
Molecular self-assembly manipulating DNA
Self-assembly and self-organization of nanostructures is an important area which often bridges the divide between organic and inorganic systems. Many self-assembly processes rely on the self-assembling nature of organic molecules, including complex species such as DNA; these methods are termed chemical or molecular self-assembly.
There has been significant and novel successes achieved in the fields of nanotechnology, particularly in the formation of nanostructures using guided molecular self-assembly methods.
The technique of self-assembly is one of the few practical strategies available to arrive at ensembles of nanostructures based on ‘bottom-up’ approach of nanotechnology. The self-assembly process, defined as the autonomous organization of components into structurally well defined aggregates, is characterized by numerous beneficial attributes; it is cost-effective, versatile, facile and the process occurs towards the system’s thermodynamic minima, resulting in stable and robust structures.
As the name suggests, it is a process in which the organization or the assembly into desired structures occurs through nature intended phenomena, either through physical or chemical processes or assisted by biomolecules to promote molecular selectivity and specificity. It is also a process in which defects are rejected energetically, and therefore the degree of perfection is relatively high.
There are numerous different mechanisms by which self-assembly of molecules and nanoclusters can be accomplished such as electrostatic and surface forces, chemical interactions, hydrophobic and hydrophilic interactions, and biomolecule-mediated self assembly techniques.
Nanotechnology and the Environment
With respect to environment, the questions facing the modern world are how nanotechnology can be used to protect the environment and how nanotechnology might affect the environment or human health.
Topics include toxicology and biological interactions of nano-materials, nanoparticle geochemistry in water and air, metrology for nano-sized materials, nanotechnology-based sensors for biological and chemical parameters of environmental interest, environmentally benign manufacturing of nanomaterials, nanotechnology-enabled green energy and power sources, and treatment and remediation of waste streams and polluted sites.
Due to the size of nanomaterials like fullerenes, nanotubes, nanowires, nanoshells, and the like - typically one billionth of a meter, that is to say approximately 70 times smaller than a red blood cell in size and close to a DNA molecule in diameter.
There is concern that these dimensions might allow them to penetrate the skin and possibly even elude the immune system to reach the brain.
Advances in Miniaturization
Electronics fuelled miniaturization with the invention of the Integrated Circuit (IC) chip. Soon, computers took over the engineering industry with CNC machines, and every industry was affected by the miniaturization wave.
The drive towards small hand-held computers and mobile communications equipment has stimulated even further miniaturization- specifically in low-power microprocessors, efficient transmitters, low mass and high-capacity battery technology and low-power GPS receivers.
This has been followed by specific developments of mobile multimedia systems such as digital cameras, spurring low-cost, low power, high-density data storage as well as high-resolution imaging sensors. Recent trends have also tended towards full integration of electronics onto a single chip (System-On-a-Chip), which is particularly applicable to picosatellite technology (Spacecraft-On-a-Chip).
Microelectronic and mechanical structures (MEMS) have led to battery-powered sensor nodes that have sensing, communication and processing capabilities. Wireless sensors networks are capable of observing the environment and making decisions based on that data.
Engineering advances has had far reaching consequences in the healthcare segment. It has devised CT scan machines, CAT scan machines, and has placed diagnostic, monitoring, and treatment tools directly into the hands of the patients as science improves and costs are reduced.
Fused Deposition Modeling
Fused Deposition Modeling (FDM) is one of the Rapid Prototyping (RP) technologies and is a non-laser process, which on the basis of a Computer Aided Design (CAD) wire-frame, surface, or solid model, deposits layers of molten thermoplastic materials or wax to build a three-dimensional (3D) part, in a temperature controlled oven-like casing.
The casing has a temperature of just below the melting point of plastic.
The FDM system functions like pen plotters, where the building material and the support material are fed in separate filaments from spools, into nozzles or heads, which heats a little and due to the extra heat the melting point of plastic is reached, and the plastic filament coming inside the head melts.
The temperature-controlled head extrudes and deposits the melted material in layers from .001 to .050 in. thick. Each layer quickly solidifies, approximately in 1/10 second, and laminates to the preceding layer.
Varying the speed of the head can control the thickness of the layer. After the necessary layering, the 3D solid part, as designed is produced, with the layering being noticeable. Support structures, if any, are subsequently removed by breaking them away from the created part, or by jets of water if they are water-soluble support structures.
FDM is usually used when an acrylonitrile-butadiene-styrene (ABS) thermal plastic part is required for a working prototype. However, FDM also uses a blend of polycarbonate/ABS, polycarbonate, and polyphenylsulfone, in standard colors.
Laminated Object Manufacturing
Laminated Object Manufacturing (LOM) is a manufacturing technique, which is frequently employed in Rapid Manufacturing (RM). Helisys, Inc. (Torrance) in 1991 commercialized LOM. Paper coated with adhesive was used as a basic material, which was cut by a laser beam into the desired shape.
The paper sheets were stacked and joined by thermal activated gluing in an automated procedure. Nowadays, plastic, composites with glass fibers and ceramics are also stacked together using the principle of LOM technology. The produced parts show a relatively high accuracy because the general layer thickness is approximately 0.1 mm.
As the layers are first joined and then cut to produce the required parts, the procedure is exactly a hybrid between additive and subtractive manufacturing. However, the joining step is dominating so that LOM can be classified as an additive technology.
It should be noted that the mechanical and/or thermal properties of such LOM parts are insufficient for applications in many cases. One important example hereby is the manufacturing of functional tools like molds. Therefore, metal sheet as a LOM base material is a field of research, too.
Nanotechnology Applications
The field of nanotechnology is now explored worldwide by academia, research centers and industries.
Applications and products are appearing on the market progressively. Nanotechnology is often merged with microtechnology to enable particular functionalities.
It is applied on macroscopic products to enhance functionality. Many disciplines such as physics, chemistry, enginnering, biology, and informatics are now converging into multi-disciplinary department in order to develop micro- and nanotechnology based products.
Nanotechnology applications are most evident in the aerospace field, which requires a very interdisciplinary engineering approach with a very wide field of view.
Titanium alloys and CNC machining
Titanium alloys are extensively used in the aerospace industry besides other industries like medical, marine, jewelry, etc. Most aircraft engines have a significant amount of titanium alloys in their parts with the most commonly used being Ti-6Al-4V alloy. However, the unpredictable machining behavior of the titanium alloy makes it very difficult to machine.
One factor responsible for limiting the cutting parameters during CNC machining of titanium alloys is the cutting temperature. Success in CNC machining of titanium alloys depends largely on overcoming several of the inherent properties of the metal. Titanium alloys have low chip-tool contact area and the thermal conductivity of these metals is considerably low (about 7,3 W/m K). This combination of small contact area and low thermal conductivity results in very high cutting temperatures and impose a constraint on the usage of higher cutting speeds.
In addition, during the cutting of metal, high temperatures are generated in the region of the tool cutting edge, and these temperatures have a controlling influence on the rate of wear of the cutting tool and on the friction between chip and tool.
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