Sunday, May 29, 2011

On the Variable Value of Recycling

A new and very interesting paper by Gutowski et al [1] (also up at ScienceDaily) discusses the variable value of recycling - more specifically, whether there are energy savings benefits is not always clear; and in some cases, the benefits, if any, are small.  From [1]:

Remanufacturing products that can substitute for new products are generally claimed to save energy.  These claims are made from studies that look mainly at the differences in materials production and manufacturing.  However, when the use phase is included, the situation can change radically. ... For most of these products, the use phase energy dominates that for materials materials production and manufacturing combined.  As a result, small changes in use phase can overwhelm the claimed savings from materials production and manufacturing.

Gutowski et al look at 25 case studies in 8 product groups, including furniture, clothing, computers, electric motors, tires, appliances, engines, and toner cartridges.  In these 25 case studies, it was found that there were only 8 cases of clear energy savings, generally grouped into office furniture (office chair, office desk), textiles (clothing), and select electronic components (laptops and monitors).  The first two categories experience an energy savings with reuse because the usage energy / energy of operation is so low [1].  For the electronics, on the other hand, "energy efficiency improvements within the same kind of devices over the time period (2001-2005) are not large enough to overcome the manufacturing phase savings achieved by reusing."  On the other end of the spectrum, products which are best bought new include high-usage appliances such as dishwashers and refrigerators, and other electronic components (again, including laptops and monitors).  In these cases [1], "the use phase energy has changed significantly due to efficiency mandates and/or the introduction of new efficient technologies." 

So what does this mean to materials science and engineering?  New materials are being developed to improve the efficiency of product use, such as through lighter weight which leads to improved fuel economy, or through improved energy maintenance / control / storage leading to reduced energy loss.  As outlined in Ashby [2], the Use phase of many product life cycles prevails as requiring the largest energy fraction, e.g. in civil aircraft (~95%), family cars (~85%), and appliances (~70%).  As such, high-performance materials often target the above products because of the potential energy savings in their respective Use phase.  These applications can also justify the high cost of the new materials because of the anticipated reductions in usage cost.  But as Ashby outlines [2], there are three additional material phases in product life cycles: 1) Production, which includes the acquisition of the raw materials and by-products of refinement; 2) Manufacture, which includes the conversion of raw materials into product shape; and 3) Disposal, which includes the ability to re-use, disassemble, and recycle the product - and is more difficult to quantify than the other three. 

The energy associated with a Disposal phase is a function of many things.  Borrowing from Ashby [2], this can include energies (or costs) associated with, for example, waste / recycled material transportation, sorting, and storage; the usable energy contained in the waste (e.g. which may be retrieved through incineration); the energy difference between embodied energy of new materials versus the recycling energy of waste materials; the energy required to develop a succeeding material/product; and perhaps most important, energy surrounding the environmental consequences.  

Although energies associated with the Disposal phase were not considered by Gutowski et al, the authors do acknowledge that the re-manufacturing route can reduce landfill burdens as well as the toxic material generation, and thus tilt increased importance to re-manufactured rather than new products.  However, I've already written on the toxicity of some materials and the projects underway to develop alternatives, e.g. replacement coatings to Cadmium and Chromium; in these cases, there is significant Disposal-based energy driving the development of new products which can reduce toxic material generation.  In order to more completely and evenly assess the value of recycling and its role in a product's life cycle - as compared to new material manufacturing - the energy of the Disposal phase needs to be better quantified and calculable.  This need is further driven by the fact that some products identified by Gutowski et al - namely, electronic devices - are experiencing diminishing services lives (estimated as 4 years in [1]) and thus their Disposal phase energies are contributing more to their overall energy fraction.

[1] T.G. Gutowski, et al.  Remanufacturing and energy savings.  Environmental Science & Technology, Vol. 45 (2011), pp. 4540-4547.
[2] M.F. Ashby.  Mechanical Selection and Mechanical Design, 4th Ed.  Butterworth-Heinemann (2010), pp. 440-447.

Sunday, May 22, 2011

Theft of Materials

Stolen Copper wire from Australian train lines.  (Source: Herald Sun/Bill Mcauley.)
Certain materials are targets of theft because to steal them the reward (meant strictly in the 'return' sense) is greater than the risk.  The reward - primarily money - depends on many factors, all interwoven, including the price of the material, its scarcity, its supply and demand, its function, its recycle-ability, its manufacture-ability, and its sell-ability.  The discussion below primarily focuses on the more general theft targets with more known and clearly-defined rewards.  In reality, however, anything can be a target for theft.


Metal Prices.  As described by Kooi [1], high metals demand on the international market is a key driver leading to scrap metal theft.  The prices of metals can change as fast as by the half-hour, reflecting the instantaneous updates of supply and demand.  A number of companies (e.g. Kitco) monitor price fluctuations in common "base" metals (e.g. Aluminum, Copper, Lead, Nickel, Zinc) as well as the more precious or scarce metals (e.g. Gold, Silver, Platinum, Palladium, and Rhodium).  Prices change quickly over even the course of a day: for example, earlier this month over an 18-hour span, the price of Copper ranged between $3.95 and $4.03 USD per pound, a non-trivial difference of 2%.  Over a 30-day span the price of copper has ranged between $4.38 and $3.91 USD per pound, a difference of more than 10%.  A quick look at the other metals listed above shows Copper is not the only metal with a rapidly fluctuating value.

Common Metal Forms.  Many of the metal items targeted for theft are those in common and recognizable forms.  Kooi [1] has reviewed many of these forms, illustrating a world-wide problem of metals stolen for scrap.  (A Google search will find many more examples).  Copper (and brass) is commonly stolen from a number of sources such as plumbing suppliers, construction sites, vacant luxury homes, cemetery headstones, fire hydrants, and even live electrical transformer stations.  Telephone land lines, street lights, and traffic signals are also frequently cut for their Copper wiring.

Metal theft patterns changes with market prices: as Copper prices dropped mid-way last year, increasing theft of steel and Aluminum metals was reported [2].  Steel is a frequent target for theft because it is common, simple, and easy to steal - as car frames, concrete re-bar, construction materials, beer kegs, manhole covers, assembled bridges, and even playground steel slides - then sold quickly at scrap value [1].  Even railway tracks have been stolen, which are then cut down and sold as scrap.  Aluminum is often stolen as castings from construction sites, car wheels, house siding, bike frames, and plumbing.  But it is not only these easily identifiable, common forms which are targets for theft.  The "scientific community should be on guard, too.  Steel vacuum chambers, electrical cables, chilling units stuffed with copper and aluminum tubing, and other metal-laden laboratory accoutrements all look like money to metal thieves..." [3].

Scarce Metal Forms.  The more scarce (and generally more valuable) metals are also targets for theft.  Catalytic converters on cars, for example, are a key target which contain thin coatings of Platinum, Palladium, and Rhodium - which in 2008 were respectively valued at approximately $65, $15, and $290 per gram [4].  While in a given catalytic converter there is not a considerable amount of these metals (a total mass in the range of ~3-7 grams depending on the converter), with increasing prices there is considerable financial motivation: converter recyclers will buy scrap converters at $70-$100 each [4].  (Recently, Platinum in the form of jewelery has also become a common target for theft.) 

Despite their value, not all metals are easy to sell.  As described by Kooi [1], stolen Gold or Silver jewelery has intrinsic value and can be sold in scrap or melted form or in their original shape.  In contrast, base metals Copper, Aluminum, brass, Zinc, Nickel, Platinum, etc. are generally not worth much (or not easy to sell) outside of scrap form; and so these metals are generally melted and re-shaped by scrap dealers or the thieves themselves.  On the other hand, the valuable metals in catalytic converters reside on a porous ceramic substrate and can not be extracted for sale using simple methods.  To extract the metals, the entire assemblies must be heated with the ceramic up to temperatures in excess of 1500 degrees Celsius, then further refined.  The complexity of this refinement limits the number of buyers for stolen converters, most of whom are designated converter recycling depots.

Valuable metals used in electronics also fit into the category of difficulty in extraction and low theft return.  However, with increasing volume of waste electronics, a correspondingly large volume of valuable metals become locked away.  I previously wrote on this subject with respect to scarce metals: Japan's 'urban mines' contain approximately 6,800 tons of Gold (currently ~$48 per gram), 60,000 tons of Silver (~$1 per gram), and 1,700 tons of Indium (approaching ~$1 per gram).  As the price of metals increase (and as the electronic device lifetime decreases), the value of electronic waste will become greater.  For example, a U.S. Geological Survey 2006 report [5] estimates that an average cell phone (weight 113 grams) contains approximately $1 worth of Copper, Silver, Gold, Palladium, and Platinum combined.  While this may appear to be a rather trivial amount, millions of cell phones are discarded annually.  The overall reward is great enough for 'urban miners' to harvest, so thievery can't be far behind as metal prices increase.

Other Materials: Polymers and Ceramics

While metals have value in both product and raw form, polymers have a much smaller market for recycling or use as raw material outside of combustible fuel.  One of the key reasons for this difference is the degradation of polymers with time and use.  For example, the mechanical properties of many polymers (e.g. thermoplastics which can be melted and re-shaped or re-purposed) decrease with increasing number of re-cycles.  This is due to breakdown of the polymer chains over time and limited "mix-ability" of polymers from different sources.  Such breakdown is very different from metals, which can be recycled a far greater number of times - essentially infinite so long as alloy elements can be separated and oxides removed/reduced.  In contrast, many polymers include additives which can not be easily separated from the base polymer, thus complicating recycling.  A second reason, it requires much more energy to produce metals from mined or native sources (e.g. ore) than from recycled sources; in this way, metals more than polymers also have far greater value once in a usable form.   

In a functional device, the value of polymeric parts is at its highest; the value also increases with the functionality of the part.  For example, carbon fiber bicycle frames are high targets for theft, not because of the price of the carbon fiber but because its function as part of a light-weight frame enables a high immediate resale value.  Another example, the polymer Dyneema is used in ballistic armor vests, among other applications.  The polymer is an ultra-high molecular weight polyethylene, which has the same monomer unit as the polyethylene used in plastic shopping bags.  The value in one form is clearly larger than that in the other; but unfortunately between the two recycle-ability is not equally directional.

Ceramic materials (e.g. granite, marble, diamond, etc.) also find themselves in the same category as the polymers and fibers: they are most valuable while providing functionality (and/or possessing immediate resale value in their current form), there are not considerable cost savings by producing from recycled sources, and the two-directional recycle-ability is limited.

Material Solutions to Theft

Solutions are required in order to identify stolen materials, but also to alert users and technicians of critical missing materials, e.g. power cables which can be hazardous if a circuit is incomplete.  There have been a number of policy changes, regulatory agencies, and security measures adopted which have helped reduce the occurrence of thievery, e.g. [1].  In the case of catalytic converters, additional measures have targeted supply chain bottlenecks (converter recycling depots) and thus reduce the success of selling stolen parts.  Complimenting these strategies, below are some of the materials and engineering solutions which have been implemented in an effort to reduce materials theft.

Identification Labels.  This is a truly fascinating field; and with novel Material Re-Design approaches below, I believe this represents the future of materials research and engineering in theft.  A few examples commercially available are:
  • One example, SmartWater [6] is a liquid-based solution which uniquely 'tags' targets (e.g. Copper wire), thereby allowing for exact detection of a stolen material under UV light.  This coded liquid remains intact on the conductor jacket even if the wire insulation is burned [1].  Spraying devices can also cover the offender in the liquid, which can't be easily removed or washed off.  
  • Another example, MicroDotDNA technology "consists of thousands of polyester substrate microdots, each the size of a grain of sand, onto which unique information is laser etched."
  • Proof-positive Copper [7] uses laser-etching methods to add serial codes and reference numbers directly on copper wires; this method can provide information on the material's owner as well as installation location and date.
Material Re-Design.  An approach to prevent theft: make something not worth stealing.  For example, target items such as manhole covers have been replaced with valueless, un-recyclable thermoplastic rejects, reinforced in order to give them the necessary mechanical properties for the application [8].  This is also a great example of re-purposing otherwise waste materials.  Another example, efforts have been made to re-design substation grounding straps in order to reduce exposed copper [1].  Of course, substitution-type material re-design won't be an option for all theft targets, but it can help concentrate focus on the higher-priority ones.

Mechanical Additions.  Finally, a number of commercial products exist to help deter or slow theft of frequently-targeted materials.  These include devices such as the Copper Keeper (to prevent theft of copper wires), as well as the Catlock and CatClamp (to prevent theft of catalytic converters).  As outlined by Kooi [1], these devices enable better security for the materials but at a cost nearly equal to replacing them.  And with increasing market prices for these sought-after metals, more sophisticated prevention approaches will be needed in the future.
Materials targeted for theft require a certain ease of identification and understanding of value; financial longevity, stability, and flexibility; omnipotence and malleability in shape and form; and so on.  Metals find themselves with all these characteristics, and are thus the most frequent target for theft.  But as explained above, all materials can be targets for theft if there is immediate resale value and if the thief understands the value of what is being stolen.

[1] B.R. Kooi.  Theft of Scrap Metal.  Problem-Oriented Guides for Police - Problem-Specific Guides Series, No. 58.  U.S. Department of Justice, April 2010.  ISBN: 978-1-935676-12-6.  (Available On-Line.)  Also see L. Bennett.  Assets under attack: metal theft, the built environment, and the dark side of the global recycling market.  Environmental Law & Management, Vol. 20 (2008), pp. 176-183. (Available On-Line.)
[2] J. Grimaldi.  Thieves ditch copper for other metals.  The Hamilton Spectator (Hamilton, Ontario), July 13, 2010, p. A03.
[3] Stealing metal, metal allergy.  Chemical & Engineering News, Vol. 85, No. 46 (2009), p. 56.
[4] A. Tullo.  The Catalyst Caper.  Chemical & Engineering News, Vol. 82, No. 22 (2008), p. 32.
[5] Recycled Cell Phones - A Treasure Trove of Valuable Metals.  U.S. Geological Survey, Fact Sheet 2006-3097 (July 2006).  (Available On-Line.
[6] BT launches nationwide campaign against cable theft; 'SmartWater' invisible paint deployed to 'tag' metal thieves.  ENP Newswire, July 27, 2010.
[7] Proof positive Copper: SouthWire's solution to the Copper theft epidemic.  Transmission & Distribution World, Vol. 62, No. 4 (2010), p. 18.
[8] S. El Haggar and L. El Hatow.  Reinforcement of thermoplastic rejects in the production of manhole covers.  Journal of Cleaner Production, Vol. 17 (2009), pp. 440-446.

Saturday, May 7, 2011

In MatSciEng: New Materials in Health and Safety

The MSDS diamond, including flammability, health, reactivity, and protective equipment information.
Despite best efforts and intentions, design and engineering for the lifetime of materials are sometimes incomplete.  In those cases, new materials can be introduced to refine and supplement the old materials or correct them entirely.  When health and safety are at risk, such new materials become the focus of international research and development effort.  In this post I've written about some new work and on-going investigation surrounding new materials in health and safety.

Nuclear Waste Storage in Clay 

A great deal of work is constantly on-going to study and monitor the safe storage of radioactive isotopes.  Care of ScienceDaily, Reich et al from the Gutenberg University Mainz have found that, in addition to other natural materials, natural clay materials can be used as storage for nuclear waste.  More specifically, it has shown that Opalinus Clay (a "Jurassic claystone" or weak mudstone) has the ability to sorb radioactive Plutonium (Pu) and Neptunium (Np) of select oxidation states from aqueous solutions.  For example, Neptunium, "...hardly diffuses through the clay, and even after a month is still almost where it started."  Longer investigations are always required when studying nuclear waste storage; for example, the radioactive half-life for Neptunium is 2.14 million years.

Replacement Coatings of Hexavalent Chromium (Cr)

Chromium metal exists most most commonly in the hexavalent oxidation state.  Hexavalent chromium is also a known human carcinogen via inhalation.  As a result, there is a great deal of motivation to find a replacement metal with similar properties, mechanical and otherwise.  However, the most common forms of hexavalent chrome are coatings - either in the electrolytic hard chrome (EHC) or decorative form - which possess a unique set of properties not easily replaced.  While some solutions do exist as partial replacements, a great deal of work is still on-going in aerospace, defense, and commercial markets to find a complete replacement for hexavalent chrome.   

Nanofiber Materials to Detect Chemical Hazards 

In a recent issue of the journal Advanced Materials [1] (also at ScienceDaily), Kelly et al have used porous Silicon (Si) filters as templates for the fabrication of carbon nanofibers.  These nanofibers have been demonstrated as sensors for hazardous chemical compounds.  More specifically, the nanofibers act as sensors for organic vapours which can cause neurological harm upon inhalation.  In application, such nanofibers can add supplementary information on whether activated charcoal air filters have expired or otherwise ceased to provide protection.

Composite Materials Extract Contaminants from Drinking Water 

Also over at ScienceDaily, a new composite 'multiphase' material has demonstrated the ability to extract radioactive and hazardous impurities - namely, radioactive iodide and arsenic - from drinking water.  Engineered by Drs. Pawlak and Venditti from NCSU, the material is made from natural and biodegradable material components hemicellulose and chitosan.  In addition, the internal structure of the 'multiphase' material is a foam, which possesses an increased surface area which likely helps increase the extraction efficiency.

Replacement of Cadmium (Cd) Metal Coatings

Similar to the work done to replace hexavalent Chromium, Cadmium (Cd) metal is also a target for replacement.  Cadmium is applied to a wide range of steel parts requiring corrosion protection, ranging from simple nuts and bolts to high-performance aircraft and defense components.  However, Cadmium itself is a toxic metal which can be released from the parts to the environment when in use.  Like Chromium, Cadmium has a unique set of material properties such as lubricity and contact resistance, as well as good corrosion resistance.  However, also like Chromium, complete Cadmium replacement still requires work as suitable material replacements have not been developed to adoptable levels.  Groups such as the Joint Cadmium Alternatives Team (JCAT) continue to drive study in this area.   

Nano-Materials can Detect and Neutralize Explosives 

Returning to ScienceDaily, work done by Prof. Apblett at the Oklahoma State University has focused on chemical-based sensing of explosives.  Apblett et al have sprayed thin coatings of catalytic Molybdenum (Mo) oxide nano-particles on various surfaces; in the presence of hydrogen peroxide-based explosives, the coatings undergo subsequent changes in colour and conductivity, both of which can be measured.  Adding additional spray, which reacts with the peroxide vapour, the coating can also disarm the explosive.  Additional studies performed by Apblett et al on Molybdenum oxides include sorbants for toxic metals, heavy metals, and radionuclides [2,3].

[1] T.L. Kelly et al. Carbon and carbon/silicon composites templated in rugate filters for the adsorption and detection of organic vapors.  Advanced Materials, Vol. 23 (2011), pp. 1776-1781.
[2] M. Chehbouni and A.W. Apblett. Molybdenum-oxide based sorbants for toxic metals.  Ceramic Transactions, Vol. 176 (2006), pp. 15-23.
[3] B.P. Kiran et al. Selective absorption of heavy metals and radionuclides from water in a direct-to-ceramic process.  Ceramic Transactions, Vol. 143 (2003), pp. 385-394.

Saturday, April 30, 2011

Processing Limitations in Nano-Materials

Example Nanomaterials from Talapin et al at the University of Chicago (link).
In the recent issue of the journal Nanotechnology (also covered at ScienceDaily), Kelly [1] has written a very interesting article concerning processing limitations of some small-scale engineering designs and constructions.  From ScienceDaily:

The overall goal when entering nanotechnologies into the market is low-cost, high-volume manufacturability, but at the same time, the materials' properties must be highly reproducible within a pre-specified limit, which Kelly states cannot happen below the 3 nm limit when trying to make arrays. 

The top-down approach to manufacturing, which Kelly states is limited, uses external tools to cut and shape large materials to contain many smaller features.  Its alternative, the bottom-up approach, involves piecing together small units, usually molecules, to construct whole materials -- much like a jigsaw puzzle -- however this process is too unpredictable for defect-free mass production of arrays.

As outlined by Kelly, standard manufacture operates under what is called 6-sigma yield - which essentially means there is a manufacturing defect rate of only 0.00034%. Those extremely tight tolerances are simply not met by the respective manufacturing processes of most nanotechnologies.  However, there can be two ways to (re)consider these limitations.

The first is that - given the need for the technology - the scales of production will follow.  Moore's Law is a well-known example.  In short, due to continuous improvement in fabrication equipment and manufacturing technology - much of which was not around when Moore's "Law" was first proposed - the number of transistors possible on a single chip has doubled every two years from the 1970's to the present day.  Based on this, it is reasonable to propose that additional improvements in manufacturing technology will help raise future nanotechnologies out of the "unmanufacturable" category.     

The second way to consider these limitations is with reference to another complex system - the human body - which also possesses a great deal of complex functionality and manufacturing.  For example, our own DNA replication and copying processes would not meet 6-sigma yield if not for clever DNA proof-reading and correcting mechanisms.  In addition, some degree of DNA error is manageable because redundancy exists.  Redundancy might not sound like an ideal situation for large-scale fabrication, but it is a useful tool to help maintain proper system functionality even if a small percentage of components are defective.  And, thermodynamically speaking, if there will be an unavoidable amount of error, then redundancy may be the path of least resistance.  Furthermore, if you accept defects will exist - if not from manufacturing, then due to in-situ operation - the design process changes from a defect-free nanotechnology to one which may perhaps even benefit from a certain concentration of them - much like the way doped semiconductors operate and interact.  But of course, this may not be possible for some nano-materials and their applications, e.g. quantum dots requiring precise confinement energies.

Ultimately, as Kelly writes, some nanotechnologies are unfortunately bound to remain on a lab bench:

Many results in nanoscience can be shown to be intrinsically unmanufacturable in terms of ideas for applications in electronic or optoelectronic components, and so will remain as scientific curiosities.

Time will tell which are the most manufacturable and which are so in a sustainable manner.  

[1] MJ Kelly. Intrinsic top-down manufacturability. Nanotechnology, Vol. 22 (2011), 245303.

Saturday, April 16, 2011

In MatSciEng: Metal Glass, Tiny Diamonds, and Fruit Fibers

Limited time to write about all new things Materials Science and Engineering has left me with a number of items I've been meaning to write about - or at least bring to light.  This post will be an update of sorts, as well as a trial run for a new format - one which I aim to use in the future in order to focus on newly-published developments for a more current and broad scope.  (Because hey, this is the internet after all.)

It's a Metal; It's a Glass

The atoms in metals are typically arranged in an ordered lattice structure, for example residing on the corners of cubes placed side-by-side.  In contrast, the molecules in glass have a much more random structure ("amorphous"), not keeping to any particular ordered or repeated lattice arrangement.  Bulk metallic glass (BMG) is a material which consists of metal atoms but without the lattice.  In most cases, BMGs possess material properties much different than the lattice metal counterpart.  For example, while strength is typically increased, ductility is decreased - which limits the ability for the BMG to be formed into shapes.   

However, as recently reviewed by Schroers et al [1] (also see ScienceDaily), BMGs can be formed using a specific method (thermoplastic blow molding) which utilizes specifically the BMG's limited ductility mechanisms.  The end result is an apparent ductility (or formability) which is significantly greater.  And because this process is inexpensive, complex shapes (particularly, shells or hollow containers) can be fabricated for a wide range of commercial products where previously only low-strength, cheap, and/or poor quality metals have been allowed.

Diamonds: Not Just for Expensive Jewelery Anymore

Keeping on with metals and glass, diamond has a number of properties advantageous to materials engineers.  For example, it has a thermal conductivity more than twice that of silver and about three times that of copper. Diamond also offers high hardness, low coefficient of thermal expansion, high melting point, and high wear resistance.  And in particulate form, diamond is relatively inexpensive: you can purchase 5 grams of sub-micron-sized synthetic diamond particulate from Alfa Aesar for about $200 (5 g is roughly 1.5 cubic centimetres).  This makes diamond particulate a good candidate for composite materials.

Which are exactly what Nadler's group from Georgia Tech Research Institute have made (from ScienceDaily).  By processing films of silver containing diamond particulate, and tailoring the amount of diamond included in the composite, the thermal properties (e.g. conductivity 25% greater than in copper, and the coefficient of thermal expansion) could be engineered for critical defense-oriented electronics.

"Ductile" Concrete

Continuing with the composites focus, I've been recently directed to the Journal of Advanced and High-Performance Materials (site here), a periodical dedicated to the advancement of materials in building sciences.  In the current issue Li [2] outlines the development and state-of-the-art of Engineered Cementitious Composite (ECC) - a composite consisting of concrete reinforced with internal fibers.  The fibers act to interrupt and distribute large cracks into smaller ones as well as keep micro-cracked concrete together (Figure 1).  The end result is a concrete material - which can also be sprayed on existing concrete as a protective layer - possessing greater damage tolerance, toughness, resilience, and energy absorption capacity (particularly in dynamic or blast loading).

Figure 1.  "Ductile" ECC in bending.  Image taken from Li [2].

I Love to Drive, Drive, Drive ...

We now interact with a variety of plastic/polymer products made from corn, potato, bamboo, as well as other "grown" materials.  Also care of ScienceDaily, fibers from pineapples and bananas are now being used to produce plastic parts and components for automotive, defense, and other high-performance applications.  The Brazilian researchers report their "nano"-cellulose polymer fibers have a stiffness almost as great as Kevlar - known for its use in bullet-proof vests - with the added benefit that the parts can be bio-degradable. 

On the other end of the spectrum, a "smart material" is a catch-all phrase that describes a material that possesses added "active" functionality as opposed to being passive only.  For example, when electric currents are passed through piezo materials, they can oscillate or vibrate.  In this fashion, automotive noise (or noise of any kind) can be dampened and eliminated altogether, thereby reducing energy losses.  On the other hand, these same materials can be used to capture the oscillation or vibration energy in a car and turn it into useful electrical energy.  Work with these kinds of materials is on-going at the Fraunhofer Institute Adaptronics Alliance in Germany (also see ScienceDaily).  Also there, safety devices are being designed consisting of magneto-rheological fluids - in other words, fluids which can change their state (from solid to water and everywhere in-between) by the strength of a magnetic field passed through them.  A large number of applications are currently in the conceptual stage, such as safety mechanisms for machinery or gears.

Take-Away Materials, Today

Finally, I'll end with a take-away message which you can literally take with you.  Materials Today has a great collection of podcasts reviewing current work being done in materials science and engineering.  In particular is a March 16 2011 podcast by Prof. James Tour at Rice University who discusses "Developments in Graphene".  Graphene - an atomically-thick version of graphite - has powerful potential in strength, conductivity, electronics, and computing.  It's a thesis topic on its own, so I'll leave that for a later post.  You can also find a number of recent articles over at Nature Materials and Science concerning recent developments with graphene.  In May of this year will be a conference in Boston regarding the "road to applications" for this powerful material in the next 5-10 years.

[1] J. Schroers et al. Thermoplastic blow molding of metals.  Materials Today, Vol. 14(1-2) (2011), pp. 14-19.
[2] V.C. Li.  High-ductility concrete for resilient infrastructures.  Journal of Advanced and High-Performance Materials, Winter 2011, pp. 16-21. (Available On-Line.)

Saturday, April 2, 2011

Lightweight Cellular Materials and Lessons from Nature

New hybrid or composite materials can be considered a combination of two or more constituent parts.  The end result is a material that possesses a set of properties not offered by either individual part alone.  A basic example, concrete reinforced with rebar is a composite material possessing both strength (provided by the concrete) and toughness (provided by the steel).

The concept of a "constituent part" can be extended further to include liquids and gases.  This is the approach taken by Ashby [1], who has considered cellular materials as hybrids of 1) solid material and 2) air.  Like composite materials consisting of two interwoven solid materials, the arrangement of the "air" component in cellular materials can also be designed through the wide range of manufacturing techniques [2]:

Variety of metal foams and their fabrication methods (from Wadley [2] - click to enlarge).

As the architecture of these materials is designed, so are the resultant characteristics (e.g. density, strength, energy absorption, resonant frequency, and the list goes on).  There is a great deal of very interesting on-going work which focuses on processing, properties, and applications of these cellular materials - most of which focuses on the light-weight structural benefits.  For more information, see bi-annual conferences Cellular Materials (CellMat) and Porous Metals / Metalic Foams (MetFoam).    

Natural Structures and Sustainable Design

Some of you may have already noticed now closely the above cellular materials mimic those of natural structures, of which a well-known example is spongy (trabecular) bone:

The internal cellular structure of spongy (trabecular) bone.  (Source: National Cancer Institute.)

The employment of this cellular structure illustrates mechanical benefits such as light weight and high load-bearing structural efficiency.  However, as recently studied by Doube et al [3] (also from ScienceDaily), this cellular design is not restricted to select organisms; in fact, the adoption of a cellular bone structure is wide-spread and is allometric (i.e. scalable with organism size) across a large number of mammals and birds from elephant to shrew.

Such a prevalent example of natural materials design is therefore not as much a niche evolutionary development as it is a generally-adopted (and powerful) design tool.  And because tools such as these came about through evolutionary means, they therefore also offer insight into new dimensions for human-powered sustainable materials design and development.

[1] M.F. Ashby.  Hybrids to fill holes in material property space.  Philosophical Magazine, Vol. 85 (2005), pp. 3235-3257.
[2] H.N.G. Wadley.  Cellular metals manufacturing.  Advanced Engineering Materials, Vol. 4 (2002), pp. 726-733.  (Available On-Line.)
[3] M. Doube, et al.  Trabecular bone scales allometrically in mammals and birds.  Proceedings of the Royal Society B, Vol. 278 (2011), DOI: 10.1098/rspb.2011.0069

Sunday, March 27, 2011

On Materials Science and Engineering in Energy

Solar tower concentrates light reflected from surrounding panels.  (Source: Paul Langrock/Zenit/Laif/Redux)
A thoroughly interesting report [1] has recently been published regarding the future of materials science and engineering in energy and related fields.  The report is available on-line here; and it is also summarized in the latest issue of the Journal of Minerals, Metals, and Materials (JOM) [2].  The report is written well and with the general public in mind; for the hobby scientist, it also helps convey a thought-provoking state-of-the-art in materials science and engineering.  To summarize the already-summarized article in JOM, the topics in the report - and subjects which will be in the forefront of future materials study - are:

Functional Surface Technology (or: making the surfaces of materials perform in new/different/improved ways).  This includes:
  • Catalysts with high selectivity and conversion efficiency.  When catalysts aren't efficient, energy is wasted.
  • Smart coating / lubricant systems for lightweight alloys.  Lighter alloys such as aluminum and magnesium tend to wear down relatively quickly. 
  • Coatings to inhibit galvanic corrosion.  Corroded materials' performance rapidly degrades.
  • Solar photovoltaic materials utilizing a broader spectrum of light.  Current solar panels only collect a fraction of the light energy available.
  • Treatment processes to rebuild or enhance surfaces.  Materials' recycle-ability, re-use, and service life can all extended.
  • High flux membranes for selective separation of atmospheric gases.  Capture of carbon dioxide emissions, for example, can be made more efficient and scalable to industrial levels.    

Higher-Performance Materials for Extreme Environments.  This includes:
  • High-temperature, phase-stable alloys.  Long-term properties degrade in industrial systems which operate using high-temperature and chemically-aggressive conditions.
  • Thermoelectric materials with high conversion efficiency.  Thermoelectric materials convert waste heat into electricity, and can help recapture lost energy.
  • Lightweight, high-strength ductile materials.  Trade-offs typically exist: strength at the expense of ductility; light weight at the expense of strength; and so on.
  • Irradiation-resistant structural alloys for nuclear applications.  Nuclear irradiation degrades the mechanical properties of many materials. 
  • High-pressure hydrogen-resistant materials.  Storage and handling of hydrogen is not an easy task.
  • Collaborative, comprehensive materials database.  Materials development can be sped and cost reduced.
  • Predictive materials performance code.  Computer modeling of materials' mechanical properties will enable rapid, inexpensive, and iterative development.

Multi-Materials Integration in Energy Systems (or: composites to provide what the individual components can't).  This includes:
  • Low-cost carbon fibers and composites manufacturing processes.  Carbon fiber products are too expensive to manufacture for widespread use.
  • Joining process for assembling multi-material structures. Some material pairs are incompatible (i.e. structurally or chemically) and can not form suitable joints or be brought into contact.
  • High energy density, low-cost battery cathodes.  Improved battery longevity, storage, and discharge will enable new alternative energy technologies.
  • Low-cost fuel cell catalyst.  A current benchmark catalyst, Platinum, rare and expensive, is not ideal.
  • Integrated computational materials engineering modeling package.  Initial composite design and proof-of-concept can be performed first through computation, saving development time and costs.

Sustainable Manufacturing of Materials.  This includes:
  • Net-shape processing of structural metals.  Scrap and waste (e.g. from machining a block of steel into its final shape) can be reduced.
  • Additive manufacturing of components and systems.  Energy-intensive production methods and industrial systems as a whole can be made more efficient.
  • Low-cost processing and energy reduction technology for metals.  Lightweight metals such as aluminum, titanium, and magnesium can benefit greatly from improved processing methods.
  • Separation of materials for recycling.  Major efficiency barriers surround the screening and sorting of mixed materials.  Carbon fiber recycling is also expensive.
  • Real-time sensor technology for gases and molten metals.  Enhanced detection methods are needed for identifying damage during processing of high-performance and energy-intensive products. 

This report covers a lot of ground regarding sustainability of materials science and engineering in energy and related fields.  But it also presents a good overview of the diversity and breadth of the meaning or interpretation of sustainability - an important point that should be considered alongside the sustainability design itself.  

[1] Linking Transformational Materials and Processing for an Energy-Efficient and Low-Carbon Economy: Creating the Vision and Accelerating Realization - Opportunity Analysis for Materials Science and Engineering.  The Mining, Metals, and Materials Society (2011).  (Available On-Line.)
[2] L. Robinson.  Opportunity analysis for MSE - Report defines pathway to a more sustainable energy future.  JOM, Vol. 63 (Issue 2) (2011), pp. 30-33.

Saturday, March 19, 2011

Materials Science in Seismic and Earthquake Engineering

Toronto's CN Tower was one of the first skyscrapers built with "mass dampers" for increased structural stability and earthquake resistance (Source).
A topic currently on the minds of many people, I thought in this post I'd take a look at material science in seismic and earthquake engineering.  In general, successful engineering for earthquakes, tsunamis, and other natural disasters requires intimate knowledge of the landscape, the likely magnitude and type of natural disaster, as well as the likely failure mechanism(s) of the building or structure.  In this regard, Japan has become one of the world leaders in earthquake engineering research, and possesses a full-scale "shaking table" at the Hyogo Earthquake Engineering Research Center [1].  The table is used to test and investigate failure modes of full-scale buildings and structures (see here for testing videos).  In order to engineer a building or structure so that it may withstand an earthquake and associated effects - for a given landscape, magnitude, and failure mechanism(s) - a number of solutions are being developed which combine architecture, civil engineering, and materials science.  (For a more general outline of these solutions, see Wikipedia.)

Springs and frequency "dampers" act to reduce the potentially catastrophic resonant coupling between external forces (e.g. from an earthquake) and the building or structure.  Because springs and dampers undergo cyclic loading, the materials used to make them must possess i) consistent cyclic mechanical properties such as high fatigue strength and low hysteresis, as well as ii) environmental stability, e.g. resistance to corrosion and embrittlement.  Friction pendulum bearings (FPBs) and metallic roller bearings operate cyclically like springs and dampers, but with the added complexity of contact dynamics.  In particular, the use of friction, which generates heat, further reduces the energy transferred to the building or structure.  In addition to high fatigue strength, low hysteresis (in some cases), and environmental stability, the materials designed for use in these bearings must also possess high wear resistance, high thermal stability, and resistance to spall formation. 

Other approaches make use of more fundamental and advanced material science concepts.  For example, Lead Rubber Bearings (LRBs) (developed in the 1970's [2]) are short blocks that consist of a core made of Lead surrounded by a rubber skin.  By utilizing strict lateral (shearing) deformation of these blocks, the building or structure above is effectively isolated from the ground below (see test video here from UCSD).  Lead is compliant (has low Young's modulus) and is very ductile, which translates to a large amount of energy that can be absorbed in the bearing during its deformation.  Lead also possesses a great deal of density (or inertia) to assist with mechanical damping.  Like the Lead component, the rubber is also compliant; but its higher elastic limit (strength) maintains the bearing shape and keeps the cyclic properties intact (i.e. low hysteresis).  The combination of these material properties in LRBs has lead to some significant improvements in seismic energy attenuation [2].

In contrast to LRBs, hysteretic dampers make specific use of materials' non-linear mechanical properties.  For example, viscous fluid dampers for structures are similar to automotive shock absorbers - they consist of a piston filled with a fluid that possesses non-linear viscosity (e.g. oil or honey, but not water).  Viscoelastic dampers behave similarly but consist of largely solid materials with visco-elastic (i.e. non-linear and hysteretic) mechanical properties.  These (or metallic dampers or yielding dampers) transform the non-linear deformation energy into an alternate form, such as heat, which can be dissipated.  A subset of metallic dampers are "superelastic" dampers made of shape-memory alloys.  Shape-memory alloys demonstrate complicated and temperature-sensitive mechanical behaviour - a thermal treatment will return a deformed piece to its shape before deformation - which has been utilized to further dissipate energy as part of a seismic damper, e.g. [3-5].

There is considerable and growing research and development in the area of materials with novel properties for seismic control and earthquake engineering - see reviews [3-5].  A great deal of this work has been done and is underway in Japan, among other earthquake-prone countries.  Engineering solutions will continue to address the diverse and unique landscapes, types and magnitudes of disaster, and failure mechanisms.  In general, however, and as I've written in the case of Haiti, the most appropriate engineering solutions must also consider geographical location, available resources, long-term outlook, and, of course, cost.

[1] Hyogo Earthquake Engineering Research Center.  Facility website:
[2] Robinson Seismic Ltd.  Company website:
[3] S. Valliappan and K. Qi.  Review of seismic vibration control using 'smart materials'.  Structural Engineering and Mechanics, Vol. 11 (2001), pp. 617-636.
[4] P. Towashiraporn et al.  Passive control methods for seismic response modification.  Progress in Structural Engineering and Materials, Vol. 4 (2002), pp. 74-86. 
[5] Y.M. Parulekar and G.R. Reddy.  Passive response control systems for seismic response reduction: a state-of-the-art review.  International Journal of Structural Stability and Dynamics, Vol. 9 (2009), pp. 151-177.

Sunday, March 13, 2011

Celebrating Engineering

March is National Engineering Month in Canada. (Image from University of Toronto.)
March is National Engineering Month (NEM), and there are a number of events happening across the country - both professionally and at Canada's academic institutions - to help celebrate the wide-ranging and far-spanning work done by engineers.  This year's NEM theme is "Designing the Future", which has a rich flexibility in interpretation but also includes concepts such as progress and sustainability in the discipline as a whole.  Besides learning more about the discipline and what engineers do at the official NEM site, here are a few sources for information:

First, Engineers Canada is the national organization that regulates the profession within the entire country.  This should be a first stop for high-level information, national programs, memberships, and projects.  On a more local scale, you can collect information specific to particular provinces - such as Professional Engineers Ontario, the Professional Engineers and Geoscientists of BC, or Engineers Nova Scotia.  There are also groups divided further by discipline, which are far too numerous to include here.  For a large list of the engineering societies which exist (both in Canada and internationally), the Wikipedia page is a good start.  Basically, there's a lot of information out there - so start Googling!

Second, academic institutions provide fun, simple, and interactive engineering demonstrations.  Designing an energy-absorption apparatus to enable the safe landing of an egg from a fall is one easy example; the design and operation of Rube Goldberg machines is another.  For example, as part of this year's NEM, the Engineering Students Societies Council of Ontario (ESSCO) put into motion the world's largest Rube Goldberg machine (constructed using the internet), which finished by lighting the CN Tower.  Watch the YouTube video here.

Universities also tend to showcase some of the more impressive and cutting-edge (not to mention concise) examples of engineering design, prototyping, and the progression from scientific and mathematical fundamentals to a working product.  Highlighted on the University of Toronto website, for example, are a number of the NEM events as well as stories that emphasize the "Designing the Future" theme in engineering disciplines.  Universities also display how discoveries in the laboratory have lead to significant commercialization opportunities.  For example, the Toronto-based engineering company Integran Technologies Inc. - co-founded by U of Toronto alumnus Dr. Gino Palumbo - has brought to fruition advancements made in the field of materials science, leading to significant and novel product developments for high-performance applications.  Not to be outdone, NEM events are also in focus this month at the University of Waterloo, University of Ottawa, Dalhousie University, or University of Alberta, among others.  Find an interactive event nearby to see the science at work and the progress behind the profession.

Also recently, there have been international events to help promote the engineering profession across the world.  Last October in the U.S., for example, the First USA Science & Engineering Festival was held in Washington D.C.  It was there that Dr. Chuck Vest - a former president of MIT and currently the president of the National Academy of Engineering (NAE) - was interviewed about the future of engineering as a career and profession (see video interview here):

"[W]e've done a miserable job of communicating the excitement and the importance and what engineers and what scientists really do ... One of the things that I think is important, is that the message gets out there that these great challenges that face humankind - in the United States and around the world - none of these things can be solved without engineering."

Dr. Vest also presents an interesting set of statistics: the percent of college graduates (both men and women) in the field of engineering is 21% in Asia, 13% in Europe, and 4.5% in the United States.  According to Dr. Vest, this problem can be rectified:

"Part of the mission of the National Academy of Engineering is to promote increases in the quality, the quantity, and the diversity of our engineering workforce; in my view it's absolutely essential for a good future for this country."   

Because Canada tends to be somewhere between the U.S. and Europe in engineering graduate percentages, communication and interaction is also critical here to help bridge gaps and build them anew to the new students and future generations of engineers.  Communication and interaction are also critical to maintain a fluent, open, and accessible scientific dialogue for those who are not engineers but who interact daily with engineering technology.  In this way, the sustainable practice of engineering design and its core principles can continue to be respected and upheld.

Sunday, March 6, 2011

The Value of Mass in Material Products

Strength versus density for a range of materials.  Source: University of Cambridge.
For a great number of material products, their mass is inextricably linked to their attractiveness and commercial success.  Mass is also a key parameter targeted in the constant development of new materials, part of the mantra "Lighter, Faster, Stronger."  For example, steel has been progressively replaced with materials such as aluminum (~35% as dense), magnesium (~22% as dense), and in some cases polymer or carbon fiber (~10-15% as dense).

The value of weight reduction is an interesting topic of discussion; it is also a topic which will constantly evolve with the development of new markets, products, as well as new materials and their properties.  The latter point is of particular focus in materials science.  For example, aluminum alloys possess a wide range of strengths, depending primarily on a) particular element additions to the aluminum base, and b) amount of mechanical working introduced.  Improvements to either can enable aluminum alloys to be applied to new products, e.g. in which a minimum strength is required and minimum density increases the product value.

However, not all commercial products and markets value (or perceive) weight reduction equally.  As described by Ashby [1], exchange constants provide the value or 'utility' of a unit change in mass.  The perceived value of these constants can be determined by graphing cost versus mass for a range of products in a given market sector.  For example, Ashby [1] has performed an exchange constant analysis for bicycles; he found that the constants in this market range from $20/kg (plain steel) to $2,000/kg (carbon fiber).  On the other hand, engineering values of these constants can be determined based on engineering criteria.  In the transport systems sector, for example, the constants are "...derived from the value of the fuel saved or of the increased payload, evaluated over the life of the system."  Namely [1]:
  • Family car: $1-2/kg;
  • Truck: $5-20/kg;
  • Civil aircraft: $100-500/kg
  • Military aircraft: $500-1,000/kg
  • Space vehicle: $3,000-$10,000/kg
In other words, it doesn't make a lot of engineering sense to produce family cars from extremely light-weight materials because weight savings aren't valued highly in that market.  (But based on the perceived value, there may be a small market for carbon fiber minivans.)

The comparison of product prices per unit weight between market sectors can also offer interesting insight into the value of mass.  From Ashby [1]:
  • Buildings (car parks to high-tech buildings): ~$0.10-$2/kg;
  • Packaging (paper to metal foil): ~$1-10/kg;
  • Marine and Offshore (bridge to luxury yacht): ~$1-100/kg;
  • Automotive (subcompact to Ferrari): ~$7-$300/kg;
  • Appliances (refrigerator to portable computer): ~$9-$1,000/kg;
  • Sports Equipment (skis to fly-fishing rod): ~$100-$10,000/kg;
  • Aerospace (light plane to space craft): ~$200-$60,000/kg; and
  • Biomedical (toothbrush to contact lens): ~$300-$100,000/kg
While there are a number of surprizes in this list - for example, that a toothbrush costs as much as a Ferrari on a weight basis - the range is a testament to the importance of market knowledge to materials engineering and weight-centric design.  As mentioned above, this list is ever-changing - responding to new markets, new materials, and new properties; but it is also closely linked with environmental changes such as volatility of materials, changes in consumer perception, and evolving political landscapes.  Because of the time required to get new materials to market, materials engineers and designers must therefore remain equally dynamic and flexible to meet the needs of consumers.

[1] M.F. Ashby.  Materials Selection in Mechanical Design, 4th Edition.  Butterworth-Heinemann (2010), pp. 208-210, 482-483.

Sunday, February 27, 2011

Scarcity of Raw Materials

A block of Indium metal.  (Source:
The most abundant elements in the earth's upper continental crust are, not surprisingly, the rock-forming elements such as Oxygen, Aluminum, Silicon, Calcium, and Iron [1].  On the other hand, there are a number of elements which are more scarce but have become critical in technological devices and products; as a result, they should require more careful consideration regarding their use, recycling, and long-term engineering investment.  This is a topic of discussion in this month's edition of the scientific journal Nature Materials [1-3].  For the present post, I thought I'd bring to light some of their informative and detailed work (italics in all cases mine). 

Elements and Their Scarcity

For an overall perspective [1]:

"There are two reasons for chemical elements to become scarce.  Some ... are simply not that abundant anywhere in the Earth's crust, whereas others are found in only a few places, which might create political issues for their supply." A few examples are the following:

Rare-Earth Metal Neodymium [Nd].  This element is a key component of small, lightweight, strong, and permanent magnets used in emerging technologies from portable electronics to hybrid vehicles to wind turbines.  King [3] has outlined approximate figures of 1 kg Nd used in every Toyota Prius and 300 kg Nd used in every wind turbine.  As China mines 97% of the global rare-earth metal supply, they possess great control of the market price as well as quality of exported form (i.e. low-value raw ore or high-value finished products) [3].  As King puts it, "if there is only one supplier there is always concern."

Tellurium [Te].  Cadmium Telluride [CdTe] solar cells are [3] "probably the highest-performing solar cells if you look at the cost per kilowatt." But Te is also essentially a by-product of copper mining, which complicates its acquisition.  According to King, Te "is produced in such small quantities that the total value of copper produced by a mine completely outweighs the value of Tellurium.  The Tellurium production is never going to drive a miner to open a mine."

Indium [In].  This element - more specifically, the compound Indium-Tin-Oxide (ITO) - is a key component in flat-panel displays, touch screens, and cell phones.  In contrast to the rare-earth metals above, Indium is considered a truly rare metal with an estimated worldwide reserve base (2007) of 6,000 tonnes [4].  Like Tellurium, Indium is obtained through mining of other materials such as Zinc [5] - and Canada produces a large percentage of the global volume (~33% [4]).  But with rarity comes high and volatile prices (fluctuating between $300-$500 per kilogram) [5], which can cause great difficulty in securing a supply chain for a product.

Platinum [Pt].  This element has been used for some time as part of catalysts.  With an estimated reserve base of 77,000 tonnes it is not quite as rare as Indium [4]; but the production of Platinum-group metals is concentrated primarily in South Africa [2,4], thus making unpredictable the cost of this metal.

Phosphorus [P].  Although a physically-abundant element, Phosphorus is also considered vulnerable because of its far-reaching inclusion in a wide range of materials and chemicals - specifically fertilizer.  As outlined in [2], "a shortage of Phosphorus fertilizer would cause significant damage to agriculture, resulting in an immediate food crisis."   

Identifying Materials Science Limitations and Solutions

As outlined in [1,2], Japan - a country consuming high volumes of scarce elements but without the ability to mine them - very early realized the problem of element shortages; Japan then spearheaded the development of an 'Element Strategy Initiative', which focuses on four key components: 1) substitution, 2) regulation, 3) reduction, and 4) recycling. 

Materials science and engineering can achieve advances in these four components of this initiative, perhaps clearest in substitution, reduction, and recycling.  First, new and less-scarce materials can be developed as alternatives to those described above.  Outlined in [2], recent examples have shown that novel lime-alumina compounds can replace ITO in some functionality.  Other recent work has focused on carbon-based replacements for ITO.  Moreover, in some cases the supply of an element provides a hard limit to the reach of a new technology: for example, mining all the world's Platinum for automobile fuel cells would be able to produce less than 5% of the global car production [2].  There are many examples of substitution-type materials science developments constantly on-going, each weighed against the current benchmarks in terms of performance, but also weight, cost, lifetime, stability, etc.  But as King [3] points out, an exact swap is not likely to happen: instead, the re-design of the material will require the re-design of the product - a reiterative process which itself possesses considerable work.

Second, improved materials product development can help reduce required material volumes.  In addition, increased efficiency of raw materials processing can help reduce front-end waste as well as enable mining from more low-grade sources [2].  Third, increased focus on materials life-cycle design - "something that is really not yet done in any significant manner" [3] - can help return scarce materials to the supply chain.  The potential value of this third component is considerable in some cases.  In Japan, for example, there are what are called 'urban mines' consisting of discarded high-tech devices; in these 'mines', Nakamura and Sato [2] cite volumes of "6,800 tons of gold (16% of the world reserves), 60,000 tons of silver (22%), and 1,700 tons of indium (15.5%)..."  In addition, as outlined in [1], "the use of rare earths in electronic gadgets has risen so much that their concentration in computers is actually higher than that in mines.  It pays to recycle." 

In short, while the context of the articles discussed focuses on scarcity, the same sentiments may be applied to even the most conventional and abundant materials.  The supplies of all elements will change over time, as will their costs (both monetary and otherwise).  In [1], it is thought that "eventually, market forces will of course even out such imbalances in supply and demand."  And with each cycle or fluctuation [2]:

"Instead of regarding this situation merely as a crisis to overcome, we should convert it to an opportunity to create a new materials science, new materials and a new industry."

[1] Elements in short supply (Editorial).  Nature Materials, Vol. 10 (2011) p. 157.
[2] E. Nakamura and K. Sato.  Managing the scarcity of chemical elements.  Nature Materials, Vol. 10 (2011) pp. 158-161.
[3] Purveyor of the rare (Interview by J. Heber).  Nature Materials, Vol. 10 (2011) pp. 162-163.
[4] D. Cohen.  Earth audit.  New Scientist, Vol. 194, Issue 2605 (2007) pp. 34-41.
[5] Mineral Commodity Summaries 2010.  U.S. Geological Survey (2010) pp. 74-75.  (Available On-Line.)

Saturday, February 19, 2011

Science and The Internet

Computers and their users.  (Source: Wendy Rejan.)
For this week's post, I thought I'd reflect on a few light tidbits I've stumbled across concerning science and The Internet.  (The "lightness" of this post I hope is captured by the image above.)  Beneath the surface of such a topic, however, there is a much deeper and richer picture I think is worth some further consideration - something I'll tackle in a future post.

Google Science.  Google Scholar (and the closely-connected Google Books) are tools instrumental in accessing a great deal of scientific and engineering literature (mostly peer-reviewed).  I use both on a constant basis, as evidenced by the references in my previous posts.  Closer to the material world, Google Patents provides a valuable reservoir improving fluency in intellectual property, a topic which should be as quickly visible to match its fast (and influential) progress.  For the current and future scientist and engineer, these tools demonstrate great value; and at a price of free, they far outperform their cost.  Finally, these tools also offer clarity, i.e. direction to more scientifically-accepted data closer to the intended targets; they also offer the credibility of expertise and peer-review, a shortfall of fully-open resources such as Wikipedia. 

While this may be old news to most of you readers, it is a more recent (but perhaps under-promoted) event held by Google that possesses a more far-reaching implications for science and The Internet: a global science-fair competition for students aged 13 to 18.  When a company like Google believes that "science can change the world," the reach, the scope, and even the face of science can certainly expect to undergo revolutionary changes.

The Value of a Blog in Science.  John Dupuis, the Head of Steacie Science & Engineering Library at York University, wrote in early 2009 an article called "If you don't have a blog, you don't have a resume."  Blogs can be a particularly useful tool not only for personal or professional writing; considering the time for science and engineering developments to reach market maturity, blogs can further be a tool to help evaluate and generate market interest, and to more personally communicate an emerging technology.  The materials industry may benefit most from the utility of such tools because it tends to have such a long time to market maturity (15-20 years, nearly as long as blogs have existed!).  Overall, a blog can help contribute more rapidly the kind of meaningful information useful to the "scientific commons"; this in turn can provide information valuable to more rapid technological commercial developments.

The Internet is Wasted on the Young.  ScienceBlogger Dr. Myers has recently written an article bringing to light a group of 8-10-year-old children who, with some supervisory help, wrote and had published a peer-reviewed scientific article in the journal Biology Letters [1].  In Dr. Myers' words, "The experiment wasn't that dramatic, but it's very cool to see the way the students' brains are operating to understand the result..."  Such exercises may become increasingly-frequent phenomena as younger scientists- and engineers-to-be undertake a personal interest followed by internet research, scientific collaboration via social networking, and writing scientific blogs to communicate and discuss their findings.  Materials science may not be the fastest discipline to adopt this progress, as analytical machines and characterization devices are costly; but as a childhood teacher of mine once taught me, most adults can't resist a) an inquisitive child in need and b) a well-written letter (or email).

The Message.  In a nutshell, The Internet isn't going anywhere.  But it is becoming an increasingly useful tool for the engineer's and scientist's toolboxes; and it should be used with its full potential in mind.

[1] P.S. Blackawton, et al.  Blackawton bees.  Biology Letters, doi: 10.1098/rsbi.2010.1057 (2010).  (Available On-Line.)

Saturday, February 12, 2011

Materials Science and Engineering in Sports

I've previously noted that, in some cases, materials in sports equipment can possess a placebo effect.  But in other cases, the role of materials science and engineering is real to performance and critical to safety.  In this week's post I'll focus on examples of both. 

Engineering a 105.4 mph Slapshot

Zdeno Chara's slapshot - the one that recently registered a new speed record - leads to the questions How does he do it? and What is his stick made of?  The answer to both questions can be answered with materials selection and knowledge of how the material has been tailored to the user.

The choice of material for a stick can be understood by considering the mechanism by which hockey sticks deflect.  At its simplest, the stick can be considered as a beam in three-point bending (Figure 1).  The outer two points are made up by 1) the hand at the top of the stick and 2) the ice surface; the hand closest to the ice provides the third point, adding force in a direction opposite the other two points. 

Figure 1.  Zdeno Chara's record-breaking slapshot.

During a slapshot, the stick stores up energy as it flexes.  In order to maximize energy without requiring too great a deflection - the energy must be released quickly, after all - a key material property of the stick is targeted: its Young's modulus.  The modulus of the material and the shape of the beam make up the stiffness; given a standard shape, beam stiffness increases with modulus. 

A materials engineering solution, especially in sports equipment, would not be complete without considering weight.  In particular, materials with greater modulus also tend to have increased densities.  A suitable engineering material can be selected by performing design analysis and optimization (for reference, see Prof. Michael F. Ashby's book [1] as an extensive resource in this field).  Specifically for beams in bending, the performance metric to be maximized is the square root of modulus, divided by density [1].  By comparing this metric for a wide range of engineering materials (see Figure 5.13, p. 98 in [1]), two groups emerge as optimal choices: woods and carbon-fiber reinforced polymer (CFRP) composites.  On a relative scale, the latter CFRP materials provide modulus values nearly 10-fold greater than those of former wood materials.  Zdeno Chara's stick is a composite, the Easton Synergy EQ50.  But not just anyone can use it: you still need to be able to flex those stiff beams to get the necessary energy output. 

Materials to Combat Concussions

There are frequent reminders that concussions occur to athletes in a number of sports, e.g. hockey, football, and baseball.  ScienceBlogger Dr. Jeffrey H. Toney has recently centered a post around football helmets, focusing on a National Geographic report that studied the impacts sustained by a 21-year old University football player in a single season (over 500 hits).  Dr. Toney's basic message is that "currently used helmets may not offer sufficient protection, particularly in cases in which players experience hundreds of hits."  Concussions are also a key topic in hockey, which has led to much materials research and development such as the Messier Project and the M11 helmet.  Baseball players can experience personal contact with 100 mph-pitches, which in some cases have led to brain trauma.  In response, improved materials and helmets, e.g. Rawlings' S100 batting helmet, have been designed to withstand such an impact.

In a collision, energy is transmitted to the head and brain, based on the pre-collision masses and velocities of the two objects, e.g. the athlete and the opposition.  The post-collision velocity is determined through conservation of momentum.  To go from its pre-collision velocity to its post-collision velocity, the head undergoes a high rate of velocity change, i.e. a high acceleration.  There is a finite acceleration that the human head can withstand without damage to the brain.  The helmet aims to reduce the transmitted energy and thus the acceleration imparted to the head; the mechanism of energy absorption is therefore critical to head protection.  

Simplified, ideal materials for energy absorption undergo permanent deformation - this deformation expends energy, reducing that transmitted to the head.  The force required to deform such a material should be high enough to absorb a maximum amount of energy; but it can't be too high such that it requires less force to deform the head rather than deform the energy-absorbing material.  Cellular polymers, e.g. foams and expanded polymers, are well-known and useful energy-absorbing materials, and which also possess low weight critical for athletes [2].  More novel materials have also been developed which improve upon the load-bearing response: for example, in the M11 helmet, liners of tubular shapes have been designed to aid in energy absorption (dubbed Seven Technology).  Future endeavors may also incorporate shape-memory polymers to offer multiple-hit capacities.  But despite these advances, as Dr. Toney suggests above, there is still work to be done.

The Future of Materials in Sports

The two parts I've provided here represent opposing sides of the same coin: a development in one can require or enable a development in the other.  In some cases, however, increased equipment performance is seen as a threat; for example, Little League International has recently banned composite baseball bats because their Bat Performance Factor (BPF) increases with use.  This returns us to an issue I previously raised regarding the evolving perception of performance increases with material developments.  At present, this appears to be the one of the most important topics in sports, and it is likely to remain so for the foreseeable future.   

[1] M.F. Ashby.  Materials Selection in Mechanical Design, 3rd Edition.  Butterworth-Heinemann (2005). (Available On-Line.)
[2] M.F. Ashby, et al.  Metal Foams - A Design Guide.  Butterworth-Heinemann (2000).

Saturday, February 5, 2011

On Sustainable Materials Innovation

A recent article written by James Moody over at SEED Magazine [1] describes a new approach to getting around Intellectual Property (IP) roadblocks experienced in developing countries.  For example, in areas where food is in short supply, where it is insecure, or in areas where malnutrition is frequent, there are technologies which may solve these problems.  However [1]:

"Many key technologies are covered by patents, because the people and companies that have invested in research and development have a reasonable expectation for profits.  Companies have been making valuable patents available for humanitarian uses for years, but quite often it has been an ad hoc effort requiring intensive legal work and expense for both [Non-Governmental Organization] NGOs and corporations."

Companies require a sufficient market potential / size in order to justify spending the time, energy, and resources necessary to develop a product - be it food, drug, material, or otherwise.  In addition, the research and development of a new product can be slowed significantly navigating through the existing IP space and avoiding infringement.  Moody's proposed solution is a Global Responsibility License (GRL) - a modular or temporary release of patent information by a patent holder to a public or not-for-profit organization.  Such a license would allow the utility of patent information for 'non-market' uses, specifically for humanitarian and development purposes; the patent holder, meanwhile, retains the economic value of the patent while further developing a new market opportunity for it.

But is this the whole story?  And do the problems outlined by Moody translate to the materials industry and its innovations?  In order to answer these questions, I'll draw from previously published works on these subjects.

Conflict, Innovation, and IP

As described by Eisenberg and Nelson [2], fundamental innovation conflict arises when trying to divide between basic science and applied technology, or, alternatively, the public and private domains. "The challenge for public policy is to devise arrangements that preserve the great advantages of an open system for basic science while still preserving profit incentives for the creation of valuable new products."  Additional conflict arises when access to even basic science becomes restricted, such as through [2-4]: ownership of research results, inefficient patent pricing, broad patent scoping, or exclusivity licensing.  On the other hand, Nelson has argued that problems of 1) assembling permissions or licenses prior to performing work, and 2) access limitation by patent holders to research having high practical promise, are not significant and of limited evidence [3].

It has been said [2] that businesses, "driven by the hope of profit and the fear of competition, have a far better feel than government agencies for the kinds of new products the market wants and can respond more quickly to emerging demand and technological opportunities."  One example given is the development of medication for AIDS patients in sub-Saharan Africa.  In this case, government subsidized the access to these inventions made by private research and development groups [2].  Similarly, the One Laptop Per Child program was in part funded by the United Nations.  On the other hand is the drive of the scientific community to contribute significant research to the scientific commons.  As outlined in [2], public funding was instrumental in the Human Genome Project; it helped generate research results in the public domain, thereby making the human genome sequence freely available.

Aside from the examples provided above, there have been proposals to further improve the efficiency of general research and its navigation through IP space.  Nelson [3] describes the incorporation of a "kind of research exemption, analogous to the fair use exemptions in copyright law, into patent law."  However, the Bayh-Dole Act encourages Universities to claim IP rights to data or technology developed during publicly-funded research; this leaves industry less willing to provide such research exemptions [2,3].  A solution may be met if the exempted research was agreed not to be patented; but Nelson believes this kind of exemption may still require a trip through Congress.  As this appears to be the kind of solution proposed by Moody [1] - but for humanitarian instead of research purposes - some work would be required to clearly define the divide between the two.      

Application to Materials Industries

The method and pathway to innovation varies significantly from field to field [4,5]. In other words, while the solution proposed by Moody may apply to some industries, new materials and their innovation do not necessarily require the same pathway or experience the same difficulties.

While considered the "source of revolutionary technologies," Maine et al [6] argue that there are two key barriers to management of new materials: 1) the long gestation period between material discovery and market introduction, and 2) the large cumulative investment necessary to commercialize them.  Of the former, I previously noted that a time period of 15 years can be required; Maine [7] lists examples of new materials innovations which have gestation periods of 20 years or more.  These mismatches and delays can be due to a number of reasons, such as separation between material and end user, unsuitable research & development (R&D) corporate strategies, or flawed R&D valuation methodologies [6].  Because of the significant costs and risks involved, therefore, IP and its ownership is critical to extract value from materials innovations; it is also critical to sustainably guide future material developments [6,7].  Maine et al [6] have recently developed an Investment Methodology for Materials (IMM) in order to help focus industry 1) on materials development and investment and 2) reduce this gestation time.  Critical in the IMM is Value Capture, the IMM component that pays particular attention to the material appropriability, i.e. the measure of degree of IP protection.

IP space traversal in the materials industry is also unique.  For example, technical alliances and collaborations are frequently undertaken between companies; collaborations preferred are generally of the small, simple, flexible, temporary, and collective type [8], somewhat analogous to Moody's proposal.  Through collaboration, a number of benefits can be realized [8], most notably the increase in innovation speed and avoidance of roadblocks by existing patents.  In fact, Niosi [8] notes that Canadian advanced materials companies could easily "invent around" existing patents, or they would simply label the results as trade secrets.  In cases where IP was generated, the main problem was found to be its division between partners, which could be defined at the outset [8].

Sustainable Materials Innovation

The materials industry, despite being a unique field, may still encounter the difficulties outlined by Moody n future innovation.  In particular, ownership of research results, inefficient patent pricing, broad patent scoping, or exclusivity licensing may increasingly exclude users from performing research or otherwise socially valuable activities [2,3].  While ownership of research results may be bypassed with non-patent agreements; while costs may be relieved by the allocation of public funds in cases where private firms have little financial incentive; while patent scoping may be narrowed through the patent office and courts; and while license acquisition can be resolved by patent holders making information widely available and on reasonable terms, considerable work is needed to examine the real economic cost of the current system [3].

Epilogue: Sustainable Materials Innovation in Canada

Canadian manufactured goods focus more on the use of traditional rather than advanced materials [8].  As a result, in Canada there is generally a small market for advanced materials development, and weakness of their production and use in the private sector [see 8].  Sustainable materials innovation in Canada may then possess a cautious optimism.  Due to the sheer volume of these native, traditional materials, sustainable materials innovation in Canada is well-suited to focus on their appropriation.  On the other hand, by focusing too narrowly on such traditional materials, Canada risks the danger of falling behind others in emerging materials markets and industries, missing out on new high-technology industries, and slowly diminishing its market share.

[1] J. Moody.  On re-thinking IP.  SEED Magazine, January 31, 2011.  (Available On-Line.)
[2] R.S. Eisenberg, R.R. Nelson.  Public vs. proprietary science: a fruitful tension?  Academic Medicine, Vol. 77 (2002) pp. 1392-1399. (Available On-Line.)
[3] R.R. Nelson.  The market economy, and the scientific commons.  Research Policy, Vol. 33 (2004) pp. 455-471.  (Available On-Line.)
[4] R.P. Merges, R.R. Nelson.  On the complex economics of patent scope.  Columbia Law Review, Vol. 90 (1990), pp. 839-916.  (Text Available On-Line.)
[5] S.G. Winter.  Patents in complex contexts: incentives and effectiveness.  In: Owning Scientific and Technical Information (1998) pp. 41-60.
[6] E. Maine, D. Probert, M. Ashby.  Investing in new materials: a tool for technology managers.  Technovation, Vol. 25 (2005) pp. 15-23.
[7] E. Maine.  Innovation and Adoption of New Materials.  Ph.D. Thesis, University of Cambridge (2000).
[8] J. Niosi.  Strategic partnerships in Canadian advanced materials.  R&D Management, Vol. 23 (1993) pp. 17-27.