Category Archives: Nanotech

Chitosan is a natural polymer with excellent biocompatibility, but poor mechanical properties. Dr. Alireza Karimi, the project manager, said the present study was an attempt to produce hydrogels with desirable biological, self-healing, mechanical and electrical properties by creating a nanocomposite with the help of carbon nanotube.

These hydrogels are able to heal themselves in case of injury without the need for outside involvement, he added.

According to the researcher, the produced structure can act as a nanoreactor and has applications in various medical fields, gas separation and energy storage.

We used of carbon nanotubes to synthetize the hydrogel. Carbon nanotubes have lend their unique mechanical and electrical properties to the finalized version of the synthetized hydrogel, he said.

Karimi maintained that the hydrogels can be used in targeted drug delivery, adding the self-healing hydrogels have the ability to modify their forms against strain and then return to their original state once the tension is removed.

According to him, the hydrogel has applications in photodynamic therapy for cancer and injuries of soft tissues such as the skin.

The results of the research have been published in ACS Applied Materials & Interfaces, Vol. 8, No. 40, 2016, pp. 27254-27263.

MS/3949152

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Researchers use nanotech. in photodynamic therapy for cancer - Mehr News Agency - English Version

LEMONT FURNACE, Pa. DNA, the molecule that contains all of our genetic information, could also be the future of nanotechnology, according to a paper recently published by a research team headed by Julio Palma, a chemistry faculty member at Penn State Fayette, The Eberly Campus.

A theoretical and computational chemist, Palma arrived at the Fayette campus in fall 2016 to serve as an assistant professor. Outside the classroom, his research involves the study of molecules and their application in alternative energy sources and nanotechnology.

DNA has the ability to function as an electronic device, and Palma was recently in charge of theoretical development for a project in which researchers modified DNA sequences to control the flow of electricity, making them function as an electrical switch. This scientific contribution was published in the article Gate-controlled conductance switching in DNA in the February 2017 edition of Nature Communications, an open-access, multidisciplinary journal containing high-quality research that represents advances of significance to specialists in the biological, physical, chemical and Earth sciences.

Read more on this subject at phys.org/news/2017-02-switched-on-dna-nano-electronic-applications.html.

In another article published last fall, Palma was part of a team that studied electron transport through a hydrogen-bonded system, finding that, for a family of structurally connected molecules, the conductance decreases as molecular polarizability increases. The results of this research appeared in the article Polarizability as a Molecular Descriptor for Conductance in Organic Molecular Circuits, which was published in the October 2016 issue of The Journal of Physical Chemistry.

Palma encourages his students at Penn State Fayette to conduct research, and is currently working on separate projects with Anastazia Polakovsky, Janai Showman and Jaira Wells, all three of whom will present their findings at the upcoming campus Learning Fair.

It is never too early to begin scientific research, according to Palma, who knows firsthand that it can greatly benefit undergraduate students. Research experience allows students to reinforce concepts that they learn in their classrooms, to improve their critical-thinking skills, to acquire knowledge that is not taught in traditional courses, and have the opportunity to research a specific topic nobody has studied before, he said.

Palma added that having experience with research can also influence students in their decision to pursue a higher degree. I am excited and proud to be at Penn State Fayette working with three talented students, he said, and I am eager to continue developing new opportunities in the future so more students can have the chance to learn and grow from participating in research.

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Chemistry faculty member explores DNA and nanotech in latest research project - Penn State News

Sharp investors may be looking to examine the Williams Percent Range or Williams %R. Developed by Larry Williams, this indicator helps spot overbought and oversold market conditions. The Williams %R shows how the current closing price compares to previous highs/lows over a specified period. NanoTech Entertainment Inc (NTEK)s Williams Percent Range or 14 day Williams %R is sitting at -43.83. Typically, if the value heads above -20, the stock may be considered to be overbought. On the flip side, if the indicator goes under -80, this may signal that the stock is oversold.

Another technical indicator that might serve as a powerful resource for measuring trend strength is the Average Directional Index or ADX. The ADX was introduced by J. Welles Wilder in the late 1970s and it has stood the test of time. The ADX is typically used in conjunction with the Plus Directional Indicator (+DI) and Minus Directional Indicator (-DI) to help spot trend direction as well as trend strength. At the time of writing, the 14-day ADX for NanoTech Entertainment Inc (NTEK) is noted at 38.37. Many technical analysts believe that an ADX value over 25 would suggest a strong trend. A reading under 20 would indicate no trend, and a reading from 20-25 would suggest that there is no clear trend signal.

Investors may use various technical indicators to help spot trends and buy/sell signals. Presently, NanoTech Entertainment Inc (NTEK) has a 14-day Commodity Channel Index (CCI) of 135.3. The CCI was developed by Donald Lambert. The assumption behind the indicator is that investment instruments move in cycles with highs and lows coming at certain periodic intervals. The original guidelines focused on creating buy/sell signals when the reading moved above +100 or below -100. Traders may also use the reading to identify overbought/oversold conditions.

Taking a look at other technical levels, the 3-day RSI stands at 79.38, the 7-day sits at 85.06 and the 14-day (most common) is at 81.29. The Relative Strength Index (RSI) is an often employed momentum oscillator that is used to measure the speed and change of stock price movements. When charted, the RSI can serve as a visual means to monitor historical and current strength or weakness in a certain market. This measurement is based on closing prices over a specific period of time. As a momentum oscillator, the RSI operates in a set range. This range falls on a scale between 0 and 100. If the RSI is closer to 100, this may indicate a period of stronger momentum. On the flip side, an RSI near 0 may signal weaker momentum. The RSI was originally created by J. Welles Wilder which was introduced in his 1978 book New Concepts in Technical Trading Systems.

Keeping an eye on Moving Averages, the 50-day is 0.03, the 200-day is at 0.03, and the 7-day is 0.04. Moving averages have the ability to be used as a powerful indicator for technical stock analysis. Following multiple time frames using moving averages can help investors figure out where the stock has been and help determine where it may be possibly going. The simple moving average is a mathematical calculation that takes the average price (mean) for a given amount of time.

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Looking at the Technicals for NanoTech Entertainment Inc (NTEK) - BVN

As reported in the Science News Journal, a team of researchers at the University of Minnesota College of Food, Agricultural and Natural Sciences (CFANS) created a sponge to address this growing problem. Within seconds, the sponge can absorb mercury from a polluted water source.

The team used nanotechnology to develop a sponge that has outstanding mercury adsorption properties. Mercury contamination can now be removed to below detectable limits from tap and lake water in less than 5 seconds. It takes about 5 minutes to remove the mercury from industrial wastewater. The contamination is converted into a complex that is not toxic and the sponge can be disposed of in a landfill after use. The sponge also kills fungal and bacterial microbes.

Nano Sponge

As an illustration, if Como Lake in St. Paul were contaminated with mercury at the U.S. EPA limit, a sponge the size of a basketball would be needed to remove all of the mercury.

This is an important development for the state of Minnesota. More than 66% of the waters on Minnesotas 2004 Impaired Waters List are compromised as the mercury contamination in those waters ranges from 0.27 to 12.43 ng/L (the EPA limit is 2 ng/L).

Many Great Lake States and Provinces have had to establish fish consumption guidelines, as mercury contamination of lake waters leads to mercury accumulation in fish. It is advised that a number of fish species store bought or caught in the Great Lakes should not be consumed more than once a week or even once a month.

A reduced deposition of mercury is also projected to have economic benefits. U.S. EPA forecasts show that reducing mercury emissions to the latest established effluent limit standards would result in 130,000 fewer asthma attacks, 11,000 fewer premature deaths and 4,700 fewer heart attacks each year. That translates to between $37 billion and $90 billion in annual monetized benefits.

The new technology would have an impact on inspiring new regulations in addition to improving aquatic life, air and water quality, and public health. Technology shapes regulations and this, in turn, determines the value of the market.

Excerpt from:

Nanotech Sponge Removes Mercury from Water - HazMat Management Magazine (subscription)

DUBLIN--(BUSINESS WIRE)--Research and Markets has announced the addition of the "Nanotech: Making Photovoltaics Possible 2017" report to their offering.

This research report takes a look at how nanotechnology is changing the world of solar photovoltaics and making possible advances which earlier one could not even possibly imagine. The report looks at the technology which is making this possible. Basics of nanotechnology, of photovoltaics, of the current PV industry worldwide, and of course, of the usage of solar power worldwide, is all analyzed in this report. Information on companies making possible the usage of nanotechnology to further increase the profitability of photovoltaics is also provided in this report.

Presently, the climate of economic difficulty facing the world is resulting in a rising demand for going green. An attempt is being made to stimulate economies by an expansion of government spending in the areas of sustainability, energy conservation and renewable energy. However the credit crunch and wild swings in the price of oil could get in the way of these nanotech solutions being aggressively pursued.

Key Topics Covered:

A. Executive Summary

B. Introduction to Solar Energy

C. About Nanotechnology

D. Introduction to Solar Photovoltaics

E. Photovoltaics and Nanotechnology

F. Applications of Nanotechnology in Energy

G. Global Scenario and R&D of Nano in Solar Cells

H. Research Trend in Nano Solar Cells

I. Technological Advancements that will Grow Nano PV Cells

J. Present Market Economics of Nano & Future Prospects

K. Leading Industry Contributors

L. Appendix

M. Glossary of Terms

Companies Mentioned

- Applied Materials

- BASF Corporation

- DuPont

- Merck KGaA

- Nano-C Inc.

- NanoFlex Power Corporation

- NanoGram Corporation (part of the Teijin Group)

- PV Nano Cell

- Samsung Group

- SunFlake

For more information about this report visit http://www.researchandmarkets.com/research/lkg24m/nanotech_making

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Nanotech Report: Making Photovoltaics Possible 2017 - Research and Markets - Business Wire (press release)

Netzsch Cerabeads

Agitator bead mill

Batch attritor

Classifying rotor in operation

Continuous attritor

What is Nanotechnology? There are a couple of definitions, or more appropriately, descriptions of Nanotechnology. Nanotechnology is science, engineering, and technology conducted at the nano-scale, which is about 1 to 100 nanometers. Nanotechnology (sometimes shortened to "nanotech") is the manipulation of matter on an atomic, molecular, and supramolecular scale. The earliest, widespread description of nanotechnology referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as molecular nanotechnology. A more generalized description of nanotechnology was subsequently established by the National Nanotechnology Initiative, which defines nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100 nanometers. Nanometer sized particles are desirable in many industries, including active pharmaceuticals, pigments, technical ceramics, crop protection, new energy, and electronics. The obvious benefit of particles in the nanometer range is to improve performance of existing products or formulations due to the increased surface area that will be available. However, new products can also be developed by processing in the nanometer range. Innovation has driven many ceramics industry researchers to look to nanoparticles materials ground finer than 200 nanometers (nm) to enhance product performance or unlock new applications for ceramic materials. Pharmaceutical scientists have enhanced the performance of drug compounds to improve dissolution, solubility, and therefore bioavailability, resulting in more effective compounds that are more cost efficient, and most importantly, with less risks and side effects for the patient. Click here for information about the PBS Toronto event, May 16-18, 2017

As a company specialized in size reduction to this scale, we didnt invent or create nanotechnology we enable it! Traditionally, producing sub-micron sized particles has only been possible through wet media milling. Recent developments in dry grinding technology, specifically fluidized bed jet mills, have enabled the production of nanoparticles through a jet milling method using steam. Considering the advantages and applications of each method described below will enable the producing company to choose the most appropriate method and equipment to achieve the desired results. Lets take a look at both technologies and how they evolved to enable Nano. What is Media Milling? Media milling is a process wherein a charge of grinding media (steel or ceramic balls, cylinders, or fine media) is accelerated in either a rotating cylinder or drum (traditional tumbling ball mill) or a stationary vertical or horizontal vessel with a rotating shaft. Media mills can be either a wet or dry process. However, higher fineness is achieved when using wet milling. In each of the media mill types described below, successively finer grinding media can be used. The capability of a system to reach a certain fineness is directly related to the size of the grinding media.

Ball Mills Ball mills, the simplest form of media mills, are rotating cylinders filled with grinding media. Ball mills employ steel or ceramic spherical grinding media that can range from to several in. in dam, cylinders (Cylpebs) of similar dimensions, flint pebbles, or media of the same material that is being ground (autogenous grinding). In some applications, rods may even be used. The ball mill rotates on its horizontal axis so that the media cascades causing size reduction by impact and sheer forces. Feed material size for ball mills is usually less than 1 in., and they are effective to produce a particle size range of 5-500, in some cases as fine as 1, but this is usually the limit. When mills are emptied, the slurry is discharged through a grate which retains the grinding media in the mill while allowing the product to pass.

Ball mills work well with brittle, hard materials, and can mill and blend materials at the same time. They are not suitable for elastic, fibrous, or ductile materials.

Ball mills can be very large, 5-6 m in dam, and even larger with input power up to 20 megawatts. The largest mills are used in mining operations.

Attritor Mills In attritor mills, smaller grinding media is employed ranging from 1/8 to about 3/8 in. The most common media types are stainless steel, chrome steel, tungsten carbide, or ceramic. There are two basic processes for attritor mills: batch and continuous. Typical feed material size is below 2 mm.

In a batch attritor, the material to be ground and the grinding media are placed in a stationary, jacketed grinding tank. The media and suspension are agitated by arms mounted on the shaft, rotating at high speed, exerting impact and shear forces on the particles, resulting in size reduction and excellent dispersion. Attritors, like ball mills, can create high-intensity mixing or blending of materials, whether introduced together into the mill or added during the process. Premixing is not necessary, but can be beneficial in introducing a well dispersed and wetted material to the process. Premixing can reduce processing time and result in less wear in the mill. While a batch attritor is not a continuous process, there is a pump that keeps material circulating from a bottom discharge and back to the top of the stationary tank. Media is retained in the mill by a screen or grate at the discharge. Circulation aids in maintaining batch uniformity and controlling cycle time. During processing, the batch can be evaluated for fineness, solids content, chemistry, or other parameters that may be critical to the process. Because the mill is an open tank, adjustments can be made to these parameters, as well as determine when the process reaches its end point. After the end point is reached, the batch can be discharged via the same pump used for circulation. Batch attritors can be used to process very hard-to-grind materials such as silicon carbide, tungsten carbide, and some metals. Less abrasive or hard materials can also be successfully processed, such as paints and coatings, inks, minerals, chocolate, resins, cellulose, carbon black, pigments, and dyes. Typical batch attritors can be as large as 500-600 gal, with slurry volume about half the total tank volume. A continuous attritor is similar, but will usually have a slightly larger vertical length over dam than a batch type. This is to control the residence time of the suspension in the mill in order to meet a specific fineness. In the case of a continuous attritor, a well-made premix is critical to the process. Continuous attritors may also use grinding media smaller than batch attritors, as small as 0.4 mm for higher density beads. In this type, the slurry is pumped through the mill from the bottom and discharges from the top of the tank. The media is primarily retained by grids at the bottom inlet and top discharge. A continuous attritor can be a single pass process, multiple pass through a single mill, or passes through several mills using finer media in succession to reach finer particle size distributions. The advantage of a continuous attritor is that the mill size is not the limitation of batch size, therefore a much larger batch can be processed with a lower investment in equipment. There are also some attritors used in a circulation process with a larger holding tank than the mill volume and higher flow rate through the mill, but with a total residence time sufficient to reach the particle size target. The advantages with this type of process are better temperature control and a narrower particle size distribution.

Agitated Small Media Mills Agitated small media mills are the final link in the evolutionary chain to reach nanometer particle size distributions and will be covered more thoroughly (by small media, we are not referring to the size of the mill, but the size of the media). This type consists of a vertical or horizontal grinding chamber, an agitator that is a rotating shaft equipped with agitator elements, a drive motor, and a media separator (located at the mills discharge). The agitator elements are typically disks or pins. The grinding chamber is filled with grinding media up to 95 percent of the mill volume. The grinding media can be made from materials such as stainless steel and glass, as well as advanced ceramic materials such as yttrium-stabilized zirconium oxide and cerium-stabilized zirconium oxide, and can range from as large as 10 mm dam to as small as 30 microns diam. The grinding media charge is activated by the rotation of the agitator shaft to create mechanical hydraulic shearing and particle impact. In agitator bead mills, the forces tear apart the solids suspended in a suspension as they are pumped through the grinding chamber.

In operation, a premix suspension containing the coarse material is pumped through the mill from a feed tank. The material flows into the grinding chamber and downward into the spaces between the grinding media. The agitator rotates at typical tip speeds between 4 and 20 m/s. The media move around the chamber and impart impact, compression, and shear forces to the suspended particles, fracturing or dispersing them. The suspension can be recirculated multiple times (known as high flow recirculation) with each pass having a short residence time in the mill chamber (approximately 30 seconds) until reaching the end product fineness specification, or pass only once (passage mode) through the mill to a product tank with a longer residence time in the mill chamber (12 minutes).

Each mode has advantages and disadvantages. The main advantage of passage mode is simplicity for those applications where the end particle size can be reached in a single pass or at most two passes. However, theres no guarantee that every particle passes through the mills highest-energy zones; therefore the final particle size distribution (PSD) may be wider than desired.

There are two variations of passage mode--pendular and serial mode--to potentially address this issue. Pendular mode ensures that more of the particles pass through the mills highest-energy zones. Using a high flow rate and two or more passes, the required particle size and a steeper PSD may be reached with a lower total residence time. This modes higher flow rate also results in less material heating, but the material is handled two or more times, which is undesirable in some applications.

The serial mode allows the use of two mills with different grinding media sizes a larger size in the first mill takes a coarse feed material to a size that allows the next mill to use finer media to reach the final desired particle size. In this way two-step grinding is accomplished in a single process.

If the material requires more than two or three passes, the high flow circulation mode may be the best option. In this mode, all particles ultimately pass through the mills highest-energy zones and achieve the steepest PSD and finest particle size. The circulation modes high flow rate also gives the material a short residence time, keeping both the material and the mill cooler and allowing accurate control of the material temperature.

Factors influencing the ultimate particle size: * Formulation of the premix (solids content and viscosity) * Quality of the premix (particle size distribution and oversize particles) * The grinding media used (bead size and density) * Media filling level in the mill * Agitator speed * Flow rate through the mill

Factors that are monitored during operation * Motor power consumed * Discharge temperature of the suspension * Inlet pressure of the suspension to the mill * Cooling water temperature and flow

Depending on the material to be ground and the objective or end-use of the resulting product, one of two types of media milling processes may be chosen. In comminution, particles are ground within the slurry by high-pressure shearing and impact forces to break apart the actual particles. In de-agglomeration, the small particles that are joined together are broken apart and separated without changing their primary size or structure. In some cases, both comminution and de-agglomeration are used on a single product. As mentioned, the size of the grinding media has a direct relationship to the size of the finished product. As a rule of thumb, the final median size will be approximately 1/1000 the media diam. So, to reach a median particle size of 100 nanometers, a grinding media dam of 100 microns is used. Media as small as 30 microns is sometimes used to reach a median particle size less than 30 nanometers. With very small grinding media, the separation process becomes more critical. In ball mills and attritors, the grinding media is retained in the mill by physical interference of a screen or grate. This is not feasible, or even possible, when using the finest media. When using media smaller than 200 microns, and considering that some slurries can increase in viscosity during milling, the media can be transported all the way to the separator screen by the suspensions flow forces though the mill, causing screen blockage. In such a case, the best media separator is a classifying rotor. Generally, the centrifugal forces it generates ensure media separation from the suspension. This is quite similar to air classification in a dry process, except that the classifier in a dry process is employed to separate coarse from fine product fractions. In a wet media mill, the coarse fraction is the grinding media.

There are several variations, and recent advancements, of centrifugal media separation systems, but the graphic demonstrates the effectiveness of this design to retain media in the mill. This is a significant contributing factor in the capability to use the fine grinding media needed to enable milling into the nanometer size range. Agitator small media mill chambers range in size from 15 ml in pharmaceutical development mills to 50,000-l mills used in mining and precious metal recovery processes.

Advantages and Disadvantages of Media Milling There are many advantages to media milling. The primary reason to select media milling is that the process can produce uniform particle size distributions in the micron and submicron (or nanometer) range. Dry-milled materials have the tendency to agglomerate after processing, or when later added to liquid, will also tend to agglomerate. This can be avoided when initially mixed with the liquid carrier and processed in a wet media mill. Wet milling encapsulates the dry particle, surrounding it with liquid and preventing re-agglomeration. Further, and long-term stabilization of the suspension using either electrostatic charge control or long-chain molecules can be achieved. There are disadvantages as well. One is contamination. A media milling process produces contamination due to wear of the grinding media and internal mill surfaces. This can be mitigated by selecting the proper wear-protection measures (wear protection of the mill and high-quality grinding media) and by adopting processing conditions to fit the requirement, without overgrinding. If a material simply requires de-agglomeration, a low-energy grinding process may be all that is needed. High-energy milling using high agitator speed (as used in primary grinding or comminution), will only create wear. Low agitator tip speeds significantly reduce wear and energy use. The other disadvantage comes when a material is ultimately used as a dry powder. Once wet grinding is completed, an energy intensive drying step is needed to complete the process. A dry process can be an advantage in these cases.

Dry Milling Technology to Produce Nanometer Particle Size Distributions Only recently has a dry process been able to consistently produce particle sizes in the nanometer range with a steep particle size distribution. This is now done with fluidized bed jet mills using superheated steam instead of compressed air. This too has been an evolution in grinding technology from simple spiral and loop jet mills, to opposed jet mills, and the most effective jet milling technology to date - fluidized bed jet mills. A further advance in this technology is the use of superheated steam to both increase energy input into the milling process and enable the separation of particles in the nanometer range.

Spiral Jet Mills Spiral jet mills were first used in the 1930s to enhance the dry milling process to reach particle size distributions with median particle size in the range of 1-10 microns, and in fact used steam as the grinding gas. Spiral jet mills are known for simple construction and simple operation without moving parts. Size reduction is accomplished by particle to particle and particle to wall collisions. Control of the particle size is mainly a function of a free vortex classification flow. Free vortex classification occurs when particles are introduced into a circumferential airstream. The heavier (coarser) particles remain on the outer periphery of the flow stream influenced by mass force created by centrifugal forces, while the lighter (finer) particles are drawn to center by drag force (effect of the fluid stream usually air) and exit the mill from the centrally located outlet with the air. The grinding process occurs while particles are circulating near the peripheral wall of the mill. There they are accelerated by grinding gas nozzles located on the peripheral wall. The acceleration results in the aforementioned particle to particle and particle to wall collisions. As the particles are reduced in size they migrate with the gas flow towards the central outlet and spiral out of the mill. Since there is no active classification in the mill to control the coarse particles, the particle size distributions tend to be wide, yet high fineness can be achieved in the median size. In order to keep the oversize particles to a minimum, or to reach a given median size, there was a tendency to create a high percentage of fine particles by overgrinding. When processing hard or abrasive materials, significant wear can occur due to contact with the wall and in these cases, hardened or ceramic materials are used for protection.

Loop Jet Mills A further step was taken in the development of the loop jet mill with the goal of improving the sharpness of the cut control of the coarse fraction. Like the spiral jet mill, there are no moving parts in the loop jet mill, and size reduction is a function of particle to particle and particle to wall collisions. Loop jet mills have their grinding nozzles located just after the feed inlet. In the same manner as the spiral jet mill, the coarser particles circulate on the outer wall, while the finer ground particles migrate to the inner wall. Here there is a difference in that the finer particles migrating to, and circulating on, the inner wall follow the inner wall surface and change direction as they exit the mill. There is also an externally adjustable barrier inside the mill to help control the migration of coarse particles to maintain their flow on the outer periphery until they are fine enough to exit the mill.

Classification The following mills all use internal dynamic air classification to control the upper particle size limit of the distribution. The following is a description of that process. Classification is the separation of particles according to their settling velocity in a gas or other fluid. In powder processing using a dynamic air classifier it is the separation of particles according to the effect of dynamic forces on the particles. There are two primary dynamic forces of air classification acting on the particles. The first is mass force. This is the force exerted on a particle by gravity, inertia, or centrifugal force. In this case it is centrifugal force generated by the classifier wheel. Mass force has a greater influence on coarse particles. The second is drag force. This is the force exerted on a particle by the surrounding fluid medium. In the case of dry classification, the fluid is a gas. Drag force has a greater influence on fine particles. There are also certain material parameters affecting air classification. These are material density, particle shape, and particle size. Gas parameters affecting air classification are the gas viscosity and gas density. As described in the graphic, higher density particles tend to classify finer. Therefore once would expect a material such as tungsten carbide to have a finer cut point than calcium carbonate at identical process conditions. Particle shape also is a factor, although it is less predictable. A flaky or high aspect ratio particle may present itself in any orientation affecting its aerodynamic performance in the gas flow. For instance, a rod-like material can present itself perpendicular to the direction of the gas flow and is classified as a coarser particle. If that same particle is presented in the direction of the flow, it will perform as a finer particle. The density of the fluid is also a factor. A higher density gas (example - ambient air) compared to a lower density gas (example - steam) will exert a greater influence on a particle carrying it to the fines discharge, and resulting in a coarser cut point.

Opposed Jet Mills In opposed jet mills there is finally an integration of a dynamic forced vortex air classifier with an opposed jet mill. This design allows control of the classification cut point independent of the airflow or the feed rate. Feed material is introduced into the mill in the proximity of the classifier. If there are fine particles present in the feed stream, they may exit the system through the dynamic classifier wheel. Coarse particles are rejected by the classifier and fall through the coarse outlet of the classifier into a split stream where they are mixed with high-pressure grinding gas and accelerated into the grinding zone. In the grinding zone they impact with particles from the opposing stream. The expanded airflow carries the particles again to the classifier where the process is repeated. While there is constant feed and constant discharge of product, there is also an internal circulation of coarse or partially ground material in the mill. As the demand for fineness increases, the internal circulating load far exceeds the actual production rate. There are some advantages to this design, including active control of the particle size, which results in higher efficiency, improved product quality, and a steeper particle size distribution. But there are also several deficiencies. One is high wear on the nozzles as both air and feed material pass through. Another is the long classifier shaft that can exhibit critical speed issues. A third is the balancing of classified coarse fraction into equal streams before mixing with the high-pressure grinding gas. Still, for its time, it was a significant improvement over jet mills that came before it.

Fluidized Bed Jet Mills The fluidized bed jet mill offers several improvements over the opposed jet mill. The material is ground in a fluidized bed by particle to particle impact only. There is virtually no impact velocity against the mill wall and much less wear. Only gas flows through the nozzles significantly reducing wear. The classifier is in closer proximity to the grinding zone. Mechanically and operationally, the classifier is a much more stable compact design. There is also a more effective classifier provided by the high end suppliers of fluidized bed jet mills. There are differences in the approaches that the manufacturers take in classifier design, but most are effective in their own right. Typically the particle size distribution in a fluidized bed jet mill is much finer and much steeper than the other jet mills, including the opposed jet mill, described above. While fluidized bed jet mills, operating with ambient temperature or hot gas are better than those that preceded them, they are still not the dry process needed to grind consistently into the nanometer size range. That was the target for the development of fluidized bed jet mills using superheated steam.

Jet Mills Using Superheated Steam The demand for finer dry powder products in the submicron or nanometer scale has led to increased use of technology using superheated steam as the grinding gas. Superheated steam as the grinding gas in jet mills has been used for many decades in the spiral or loop jet mills described above and more recently in fluidized bed jet mills. There are several key factors that make this process viable. Steam can be provided to a jet mill at high pressures compared to air. At higher grinding pressures, higher jet speeds can be attained. For example, at 100 BAR absolute, the jet speed exceeds 1200 m/s, compared to 600 m/s when using air, the kinetic energy in the mill is substantially higher with a proportional increase in capacity. Steam allows a finer cut size than air by reducing the drag force conveying particles from the mill. In a jet mill, this means the particle size distribution of the product is finer. Steam jet mills of all types are successfully used in commercial applications from ceramic materials, printing applications to advanced energy processes. On the other hand, steam jet grinding cannot be used for products that are sensitive to high temperatures, such as active pharmaceuticals and organic materials. However, any inorganic material not adversely affected by high temperatures, and where fine particle sizes are desired, may be suitable for steam-jet milling. Extensive testing has been performed on aluminum oxide, barium titanate, ceramic pigments, glass frits, graphite, rice ash, silicon carbide, talcum, and zirconium oxide, to name a few. One last advantage: Steam jet milling is greener than conventional air jet milling. As is well known, steam is the driving force of almost all energy production worldwide. In 2015, about 86% of the electrical energy in the U.S. was generated by large power plants using fossil or nuclear fuel. Large power plants operate on average with a degree of primary energy efficiency of around 40%. Transformation and line losses cause an additional loss of about 10%. Therefore when the electricity arrives at your plant, it has a degree of efficiency (compared to the primary energy) of about 36%. When you factor in compressor efficiency, which is about 45%, the overall energy is only about 16% from primary energy to kinetic (grinding) energy in the mill. By using steam directly, the process becomes two or three times more energy efficient. Grinding with steam is greener.

The Future of Nanotechnology The needs of companies developing materials in the nanometer size range can be met with either wet media mill or dry jet mill technology. The process and end use are factors that lead to the decision which is best for the application. In some cases, steam jet milling is more energy-intensive than media milling and its use would add additional costs to the product. Although many materials are suitable for steam jet milling, some substances cannot withstand the heat of the process. And when the finished product is needed to be wet or in a solution, it may be more cost-effective to reduce its size using wet media milling rather than steam jet milling. However, when a dry end product is needed, the advantage may be with steam jet milling. Wet milling technology also continues to develop and several new designs are available today that were not available even one year ago. These designs offer improved media separation allowing the use of smaller grinding media. Smaller media enables a finer particle size distribution. Improved separation of media gives flexibility to process materials with higher solids and viscosity. Better cooling efficiency allows more energy input into milling process resulting in higher production rates. Both technologies can apply to ceramics, alternative energy materials, optical glass, pigments, coatings and industrial minerals markets to name just a few. Both are viable technologies, with advantages and disadvantages, and in some rare cases, wet media milling with small media mills and dry grinding with a steam jet mill may be considered, tested and found to be equally successful! The engineer then has an interesting choice to make!

Stephen Miranda is sales director, Netzsch Premier Technologies LLC, Exton, PA. For more information, call 484) 879-2020 or visit http://www.netzsch.com.

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The Quest for Nanotechnology and the Evolution of Wet and Dry Milling Processes - Powder Bulk Solids

Removing mercury from the water hasnt been simple and no method has been so efficient or safe until now. Abdennour Abbas, Professor of Bionanotechnology in the Department of Bioproducts and Biosystems Engineering at the University of Minnesota, and his team created a low-cost super sponge that can soak up mercury from polluted water in just a few seconds. In addition, the sponge has some other useful qualities for water clean-up.

The super sponge! Image credits: Ke Xu, Abbas Lab, University of Minnesota.

Mercury is a very toxic substance that is found to some degree in virtually every body of water. Mercury occurs naturally in the earths crust, but human activities, such as mining and using fossil fuels, have released it into the environment. Bacteria change mercury into methylmercury, which becomes more concentrated in fish and humans. Mercury is dangerous because it is a strong neurotoxin.

In many lakes, the mercury concentration is between 0.01 and 12 nanograms per liter. Even at low concentrations, mercury can cause health problems. As you go further up the food chain, the amount of mercury increases a lot. Large fish can contain a lot of mercury. Babies whose mothers eat a lot of methylmercury while theyre in the womb may have damaged neurological development. Later in life, these babies could have problems with cognitive thinking, memory, language, and attention. A worrying prospect is that up to 10% of American woman of childbearing age have enough mercury in their blood to put a developing child at risk. In adults, effects can be seen onnervous, digestive and immune systems, lungs, kidneys, skin, and eyes.

The element mercury (Hg) in liquid form. Image credits: Bionerd.

The researchers at the University of Minnesota used mercurys greatest strength to become its greatest weakness. Mercury is mostly toxic because it irreversibly binds to the selenium found in living organisms in proteins or enzymes. Selenium binds mercury very strongly.

ALSO READ These fish have evolved the ability to leap onto land -- to avoid being eaten

The researchers used nanotechnology to grow selenium nanoparticles in and on a sponge. The sponge is so efficient that it removes mercury to below detectable levels from tap and lake water in under 5 seconds. You also need a surprisingly small amount of sponge to clean a large area. For example, a basketball-sized sponge could soak up 2 ng/L of mercury in a lake that is the size of a football field and up to 15 ft deep. The sponge can also be used to clean industrial wastewaterin 5 minutes.

Professor Abbas and graduate student Snober Ahmed demonstrating the capabilities of the sponge. Image credits: Ke Xu, Abbas Lab, University of Minnesota.

Once in the sponge, the mercury is bound to the selenium irreversibly and non-toxic. It can be disposed of safely in a landfill; it releases less mercury than the Environmental Protection Agencys safety limit. As an added bonus, the sponge soaks up some other heavy metal contamination from water such as lead, copper, arsenic, and zinc. Importantly, it doesnt take any essential nutrients from lakes. The sponge can work in water, regardless its acidity. Additionally, there arent any toxic effects on human cells and the sponge has strong antimicrobial properties.

All in all, this sponge is good for aquatic life, water quality, and health. It sounds like a win-win. If used industrially, the sponge could make wastewater treatment a lot more efficient and safe. Additionally, many lakes have high mercury levels that make it not safe to eat a lot of these fish. Using this sponge could clean up polluted lakes and make the fish safe to eat!

ALSO READ Scientists turn the clock back 350 million years to show how humans lost their tails. Twice

Journal reference:Ahmed, S. et al., 2017.A Nanoselenium Sponge for Instantaneous Mercury Removal to Undetectable Levels.Advanced Functional Materials.

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New nanotech sponge sucks mercury from water in less than 5 seconds! - ZME Science

Nanotech Security Corp (NTS) PT Lowered to C$1.75 Chaffey Breeze Nanotech Security Corp logo Nanotech Security Corp (CVE:NTS) had its price objective lowered by analysts at Canaccord Genuity from C$2.00 to C$1.75 in a note issued to investors on Thursday. The brokerage presently has a speculative buy rating on the ...

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Nanotech Security Corp (NTS) PT Lowered to C$1.75 - Chaffey Breeze

For most of us, its hard to imagine what technology might look like 30 years from now. For members of theMid-Atlantc Micro/Nano Alliance (MAMNA), its a little less hard.

MAMNA was formed over 10years ago as an alliance ofcompanies, universities and government labs that are working in micro- and nano-engineering. Labs like NASA, the Naval Research Lab, the Army Research Lab and NIST are all members, as well as a bunch of local universities. It was, and is, a way of getting all the different labs and small businesses together to share resources, MAMNA PresidentBrendan Hanrahan told Technical.ly. This is important because many of the tools used in this kind of engineering are very expensive sharing access and information can lift all boats, so to speak.

The alliance is also a way for researchers working on technologies that are very far from commercialization to connect and discuss. By a way of fostering community MAMNA hold two main events every year a scientific speed networking event and a symposium. Each year the symposium has a general theme (last year was materials; this year is sensors) and a lineup of impressive speakers. For example, this springs symposium will be headlined by Nobel Prize winnerDr. John Mather.

Hanrahan himself, now a materials engineer for the Army, joined MAMNA when he was a student at the University of Maryland. He found it valuable to be around like-minded individuals. What he didnt expect was to be leading the organization some day they said, Would somebody please take over? and everyone else stepped back when I wasnt paying attention, Hanrahan laughed, by way of explaining his path to the presidency.

But leading MAMNA intersects nicely with what Hanrahan does today, which he explained as essentially trying to imagine what the Army will need in the year 2050. If youre solving a current problem youre not being imaginative enough, he said. Hanrahan does his work by looking for interesting early-stage research and thinking about what possible tech applications it could have MAMNA is a great forum for finding that research.

And what does the future of technology hold? Hanrahan, for one, is excited about the potential of new chemical sensors. I think [the sensors] are going to take wearables to the next level, he said. And as it would happen these sensors, and others, will be on display at MAMNAs upcoming symposium.

Want to see some futuristic technologies for yourself? Register here.

Tajha Chappellet-Lanier is the lead reporter for Technical.ly DC. The California native previously worked for NPR and the editorial board at USA Today. She can talk travel plans all day, and has strong opinions on the best doughnut in D.C.

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Wanna see the technology of 2050? Check out this futuristic nanotech group - Technical.ly DC

The Hindu

Flexing nanotech to prevent steel corrosion - The Hindu The Hindu Conventional methods of coating steel are effective only to a point in preventing rusting. | Photo Credit: Thulasi Kakkat · K.S. Sudhi. March 18, 2017 18:35 IST. and more »

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Flexing nanotech to prevent steel corrosion - The Hindu - The Hindu