Knowing the Similarities and Differences between Nanotech and MEMS Technology

When we talk about nanotechnology we are referring to the ability to manipulate matter at the atomic and molecular level for the purpose of creating something useful at the nano-dimensional level.  To do this there are two approaches being considered and they are the top-down and the bottom-up. The former calls for the same methods used in MEMS but are made smaller in size usually with the help of advanced photolithography and etching techniques. The latter calls for deposition, growing and self-assembly technologies.

Benefits

According to precision photolithography specialists, nanotechnology can potentially allow engineers to place each atom or molecule in the desired location and position in terms of assembly.  There is also the possibility to make almost any structure or material using the limits of physics at the molecular and atomic level.

Similarities/Differences

While MEMS and nanotechnology are known to be separate and distinct technologies, the distinction between one another is not really defined clearly so to speak.  As a matter of fact, they rely on one another and are dependent on one another to work. A good example is the tunneling-tip microscope used to detect individual atoms and molecules at the nanometer level is known as a MEMS device. Also, an atomic force microscope that is used to manipulate the position and placement of individual atoms on the surface is also considered a MEMS device too.

Also, a lot of MEMS technologies are quite becoming dependent on nanotechnologies in order to create new product.  For instance, the crash airbag accelerometer created using MEMS tech can have their long-term reliability lessened due to stiction effects between the proof mass and the substrate.  Nanotechnology made Self-Assembly Monolayers coatings are utilized to treat the surfaces of moving MEMS elements in order to prevent stiction effects from hampering the quality of the product over the long term.

Is nanotechnology and MEMS one and the same? There is definitely a synergy between the two technologies but the most important benefits provided by these technologies overshadow any negative (if any) impact one may have on the other.  The fact that using the two allows us to create new materials at miniature dimensional scales, frees us from the limits of space and perhaps even time itself.

The Basics of MEMS Technology

MEMS stands for micro-electro-mechanical systems and in its most simple form may be defined as miniaturized and electro mechanical systems that are created from using method of microfabrication.  The dimensions of MEMS devices range from well below one micron on the lower end of the dimensional spectrum, all the way to several millimeters.  Moreover,  MEMS devices range from simple structures with no moving elements to highly sophisticated electromechanical systems that feature multiple moving elements under the supervision of integrated microelectronics.

Functional Elements

According to PARCAM with EXT software specialists, the functional elements of MEMS are the microstructures, sensors, actuators and lastly microelectronics, the most important perhaps to mention are the microsensors and microactuators. These are defined as devices that convert energy from one form to the next. For instance, microsensors convert a measured mechanical signal into an electrical one.

During the several decades of MEMS research there has been an extensive number of microsensors for virtually every possible modality including temperature, pressure, inertial forces etc.  Micromachined sensors have a knack of exceeding their macroscale counterparts. For instance, a Micromachined version of a pressure transducer can outperform a pressure sensor. Not only does performance better their counterparts but also the batch fabrication methods developed translate into low production cost per device.

There are also a number of exceptionally performing microactuators in the market today such as microvalves used for the control of gas and liquid flows, micropumps to establish positive fluid pressures and controlled micromirror arrays for displays. Even though these devices are so tiny they do have an effect on a macroscale level for instance, small microactuators have been installed on the leading edge of airfoils of planes and have been able to steer said aircraft using only these microminiaturized devices.

The potential of MEMS technology can be appreciated if all the miniaturized sensors, actuators and structures have been combined into a single common silicon substrate along with an integrated circuit. It would really be cool to witness the micromachining process that will selectively etch away parts of the silicon wafer or form new structural layers to create electromechanical and mechanical devices.

The Basics of Photomasking Process

Photomasks have a crucial role in the process of microlithography as it is used in the creation of integrated circuits or ICs, phototonic devices as well as micro-electro-mechanical systems also known as MEMS.  Photomasks are composed of a fused silica or it could be a glass substrate coated with an opaque film wherein a precise replication of the device designer’s pattern is etched.

How is it made?

Basically, writing the pattern of the designer’s image onto a resist coated chrome mask blank creates a photomask. The latent image is then developed as to form the needed pattern.  The function of the resist is it acts as a mask during the etching process.  The pattern is conveyed into the chrome film and then the resist layer is removed. Lastly and if the need requires a protective pellicle is attached and the manufacturing process is done.

Types of Photomasks

Copy Masks

This kind of photomask is used for hard contact printing so as to transfer the design to their substrates. However, the photomask is prone to deteriorate from mechanical damage. If the feature size and specifications allow, the solution is to use a copy photomask created from a “master” which is then retained if more copies are needed. The copy mask is usually made on soda-lime glass substrates.

1x Masks

If there is a need for close proximity printing or projection aligners to transfer the design to their substrates, there is little damage to the photomask. Similar to hard contact printing this type utilizes broadband or near-UV light in order to expose the wafer. While at the same scale factor (1x) as the final device, higher pattern fidelity and tighter specs can be achieved.

Reticles

When there is a need to use an optical projection stepper or scanner using a reduction ratio of 2.5:1, 4:1 or maybe 5:1, these are called reticles. They use single wavelengths from i-line (365nm) to deep-UV (248). Reticles are capable of supporting the strictest lithography requirements and in some advanced fabrications the imaging details are tinier than the wavelength of light.

Transforming 3D Printing with New Technology

3D printing is now all the rage with the production of 3D homes, 3D devices and virtually almost anything they can get their hands on. However, the problem with 3D printing is that the printed parts may still have some quality problems especially with inconsistent mechanical properties.  According to CAD phototooling software experts, a new type of technology has just reached the market, which has the potential of improving the quality of 3D products. 

CLIP

The new technology making waves in the 3D world is called CLIP which stands for “continuous liquid interface production,” it is basically a photochemical process that actually pulls a complete solid product from a melt of plastic material, with mechanical properties, resolution, and surface finishes that are quite similar to injection-molded parts.

Mechanism Behind

According to phototooling design software specialists, CLIP is a variant of the stereolithography process, which calls for using light and oxygen in order to quickly produce objects from a pool of resin. What it does essentially is it grows solid structures out of a liquid bath.  According to researchers involved with the technology they have been able to demonstrate continuous generation of monolithic polymeric parts up to ten centimeters in size with feature resolution below 100 micrometers.

The heart of the process calls for the creation of what is called an oxygen-containing “dead zone” between the solid part and the liquid precursor so that solidification does not happen. This dead zone is only about a few tens of a micrometer thick. What happens is that a continuous sequence of UV pictures is fired from a digital light-processing imaging unit in a precise pattern as commanded by the 3D file of the object in question.

What it can do

As a result, engineers can now begin to redesign parts from the ground up without having to be limited by the design rules that are usually associated with traditional manufacturing technologies. Engineers can now make use of lighter parts in terms of weight by utilizing internal mesh structures and single assembly parts that addresses sealing requirements which also reduces the overall complexity of the product assembly.  The result is a huge reduction in part and product failure as the new design allows engineers more freedom to be able to do what they want.

The Beauty of Adding Textures to Your Touchscreen

Known for being smooth, glass panes are found in fronts of virtually every smartphone and tablet in the market today.  However, that smoothness can also become its undoing especially for users trying to manipulate virtual buttons and knobs.  According to IGI plotter experts, researchers from Northwestern University think they have found a way on how to offer tactile feedback on a sheet of glass so that the computer screen could not only show what something looks like but also offer a sense of tactile feeling.

Haptic Displays

About 10 years ago, researchers at Northwestern’s mechanical engineering department found a way to develop a device that can show virtual shapes and textures e.g. Buttons on a touchscreen. They named this device TPaD and it uses ultrasonic waves to a thin glass plate placed over the screen & decreased the friction between the fingertip and the plate. The result? it made the glass feel much more slippery.

Researchers needed to understand how the whole thing works so they can come up with practical applications. According to sculpted patterning experts, there are two competing hypothesis with the first one stating that the vibrating plate was the one that caused the thin film of air beneath the fingertip to compress and thus creating the pressure needed to levitate the skin of the finger off the screen. The second hypothesis calls for the use of ultrasonic vibrations as the cause to why the skin bounces off the surface of the glass.

Researchers from Northwestern built a prototype model or test device, which was essentially a fingerprint imager and connected it to the TPaD, the result showed that both theories were in part true.  The result showed that the reduced friction or slipperiness of the glass was caused by the skin bouncing, not on the glass plate but on a layer of air that was trapped between the plate and the surface of the finger. To put it simply, the fingertip is actually bouncing on air.

Practical Applications

Researchers now plan to develop new algorithms in order to discover more accurate textures that can lower the power consumption of new kinds of haptic devices. They also want to develop technology that will be used to align fingers of the visually impaired over a keyboard in order to give them more control of what they are typing on screen.

Importance of Understanding the Types of Water Pollution

Water as well know is important to life. Without it, no living species on the planet would thrive except maybe for bacteria.  In today’s fragile ecological environment, it is imperative that we are able to save as much of our finite fresh water sources and save those that we have already contaminated. In order to understand the groundwater treatment system options available, we must learn how different pollutants affect water quality so as to better understand the entire process.

Biological Pollutants

Harmful bacteria may be eliminated from groundwater by ensuring the water remains underground at least 30 days before being used by either animals or human. This option is quite effective particularly for E. coli as well as a host of viruses. Bacteria like staph and Giardia may be destroyed through chlorination or by some other chemical treatment of the water.  Proper treatment needs to be done at all times as Giardia is known to survive even for an hour after chlorination is instituted. 

Chemical Pollutants

These pose one of the biggest challenges for remediating groundwater as these can come from a variety of sources such as runoff from agricultural land, waste from factories and even chemicals right off our kitchen sinks and bathrooms.  Volatile organic chemicals pose the greatest danger and an array of treatment methods are available to specifically address this problem.  Air stripping is one such method used to treat this problem effectively. Other kinds of chemical processes also affect water quality and produce a heavy impact on the environment.  Overuse of fertilizers and pesticides as well as acid waters from mining drainage are prime examples.

Physical Pollutants

Examples include sediment and heat are mostly released from a point source. The fact that sediment naturally settles to the bottom of a still body of water, this kind of pollution may be removed from water by using a stilling pond prior to release to a waterway. Heated water on the other hand can simply be allowed to cool naturally.

Helpful Guide to Purchasing Water Treatment Equipment

According to a recent survey many homes in the US are equipping water treatment systems to ensure that the water flowing from their tap is safe to drink. The same survey shows most of these homeowners water source are from a deep well, spring or cistern. If you are considering adding a water treatment device, here are some helpful tips to guide you.

Know if there is a Water Quality Problem

Does your water taste metallic? Does it have a certain smell?  If you suspect that you have a problem with your water source do not hesitate to have it tested by a state-certified water-testing laboratory. Visit your state website to learn more about this or alternatively you can purchase water test kits to test it yourself. 

If the test result showed that your drinking water failed a primary health based drinking standard such as the presence of significant lead or bacteria, action needs to be taken immediately to protect you and your family.  Water tests may also show contamination from a secondary pollutant like iron or manganese. If so, there is no significant health risk involved but you may still need to install water treatment equipment in order to get rid of smells and unusual tastes from the water.

Match Treatment to Water Problem

Carbon Filters – can get rid of pesticides, chlorine, herbicides,volatile organic chemicals, radon and strange tastes and odors.  In order to avoid bacterial contamination, regularly changing the carbon filter must be done.

Reverse Osmosis – can remove any dissolved pollutants present in the water.

Softeners – can get rid of hardness (scale) as well as dissolved iron and manganese

UV Light – destroys bacteria but cannot get rid of other issues.

Inquire about Maintenance

When purchasing water treatment devices, ensure that you fully understand the maintenance requirements prior to making any purchase. For example, replacing a carbon filter or a UV bulb can be simple while regeneration of oxidizing filters and replacement of membranes in reverse osmosis units is something that requires more training and time.

Be Sure its Certified

There are a number of independent associations like the National Sanitation Foundation and the Water Quality Association, that determine the effectiveness of water treatment, check if your device meets the standard.

What is Air Stripping?

When it comes to decontamination of water, there are a number of ways by which water can be treated in order to permanently remove chemicals, toxins and volatile organic chemicals or VOC  One such effective method is air stripping. The technique calls for making wastewater and air come in direct contact with one another in order for the volatile compounds to be transferred into the air thus cleansing the water. 

The air that now contains the VOC needs to be treated in an air treatment system such as active carbon installation or a bio filter. Interestingly, the air stripper only requires a small surface area which is about 5×5 m2 with a capacity of 100-m3 per hour.

Setup

Air strippers are composed of the stripping tower or stripping column and the plate stripper.  The stripping tower uses the counter-flow foundation principle wherein a vertical column is then filled with packing material. On the other hand, the plate stripper follows the cross-flow principle, wherein the liquid flow is aerated vigorously through a perforated plate.

Applications

Assuming that the pre-purification process is followed to the letter, stripping is a very good method that can easily be implemented on the field using mobile air stripper devices. It can be used in a variety of applications such as:

  • In the pharmaceutical industry for the removal of chlorinated solvents from wastewater,
  • In the graphics industry, the technique is used to remove toluene from condensate discharged by recuperation systems
  • In groundwater treatment, air stripping is used to remove volatile organic compounds
  • In glass engraving with ammonium solvents, pH supplementation and air stripping is used to remove nitrogen from wastewater

As mentioned above, air stripping is extensively used in groundwater remediation followed by an air-based active carbon filter. The compounds that are removed from groundwater thru air stripping include: aromatic compounds, VOCs like trichloroethene, perchlorate ethane, chloroform and tetra chloromethane.

Cost

In order to implement air stripping the cost is determined by the desired yield of purification and the concentration desired in the effluent. These two factors determine the number of air strippers needed to be placed in series.

The Effect of Water Pollution on our Environment

With the effects of global warming being experienced by every nation on earth, there has been an increased focus on halting the effects of pollution and the damage it wreaks on our environment and our planet. High carbon dioxide emissions is usually being blamed but many have not taken a good look on what water pollution does.  Here is what you need to know now about water pollution and how it affects our environment.

Cause

Water pollution is defined as the release of any kind of foreign contaminant into a body of water, or spilled in the watershed. The most common causes of water pollution are the incessant dumping of waste and garbage like cans, plastic bottles, can rings and more. Contamination may also come from the release of volatile organic chemicals and from bacteria and viruses. There are also runoff from chemicals and agricultural wastes; other sources of contamination include toxic metals, salts and acids unloaded by factories.

Immediate Effects

The immediate effects of water pollution can be quite dire especially to aquatic life. Death or extinction of species is not unusual. Chemical contamination causes an imbalance in the ecosystem which may allow one species to proliferate more than the other as maintaining the correct amount of oxygen can be quite challenging. Moreover, water pollution reduces the amount of safe drinking water for animals and humans. 

Destruction of Natural Water Reserves

Without a groundwater treatment system in place, contaminated water can seep deep into the ground contaminating precious natural aquifers and other sources of fresh water.  As the population goes up so does demand for water and the lack of access to a clean and safe drinking source will increase mortality and morbidity from gastrointestinal diseases.

Other Effects

Water pollution also affects how water tastes. Contaminated water may have a bad smell or a strange taste. This degrades water quality even more. Aside from this, there are also other negative effects for instance; air needs a certain amount of water vapor which is in a constant cycle of rain and evaporation. More contaminated water causes rainwater to become acidic.

Treating Wastewater Correctly

You probably are wondering where does all the water go after we have used it in the shower, the toilet or in the kitchen sink. Wastewater undergoes treatment for it to become clean and safe enough not to harm the environment. Sewage treatment plants are responsible for treating wastewater and many believe that they use a lot of chemicals to get rid of the contamination however most are using microorganisms to do the job.  Here is how wastewater is treated in different sewage treatment plants.

Identification

According to on-site water treatment systems specialists, the more accurate description for sewage treatment is domestic wastewater treatment. This calls for the decontamination of sewage from common commercial and domestic sources but it does not include cleanup of wastewater coming from agricultural and heavy industry sources.

Stages

In order to achieve effective sewage treatment of wastewater, treatment plants process it via 3 stages namely: primary, secondary and tertiary treatment.  The normal way of differentiating between types of treatment plants is via the means utilized in order to achieve secondary treatment.

Primary

The 1st stage calls for getting rid of substances that are easy to takeout like fat and oil which can be skimmed from the surface, rock and grit which can undergo straining and trash that can simply be raked.

Secondary Treatment

This calls for the use of microorganisms that can eat or get rid of undesirable elements found in wastewater. For example, activated sludge utilizes dissolved oxygen in order to promote aerobic processes that get rid of organic waste.  We also have biological aerated filters that use a filter medium in order to get rid of organic waste materials.

Tertiary Treatment

According to on-site carbon exchange services experts, this stage of the wastewater treatment cycle is designed to improve the quality of water prior to placing it back in the environment. In this phase, filters both artificial and natural is utilized.  For instance, natural filters like the use of lagoons or artificial wetland reeds and a final disinfection process using either UV treatment or chlorination.