Tag Archives: titanium

Metallic wood.

Researcher devise ‘metallic wood’ that’s stronger than titanium but could float on water

A team of US researchers has developed a light, but incredibly strong new material — they’re calling it metallic wood. This material, despite being a porous sheet of nickel, is as strong as titanium but four to five times lighter.

Metallic wood.

A microscopic sample of the researchers’ “metallic wood.”
Image credits University of Pennsylvania.

The way atoms stack in a lump of metal determines how strong that metal is — but we can’t (yet) produce such objects. For example, a sample of perfectly-stacked titanium would be ten times as strong as any titanium we can create today. This comes down to random defects that form in the manufacturing process, impacting the metal’s overall properties.  Materials researchers have been trying to exploit this phenomenon by taking an architectural approach, controlling the metal’s nanoscale layout to unlock the mechanical properties that arise at the nanoscale, where defects have reduced impact.

In a new study, researchers at the University of Pennsylvania’s School of Engineering and Applied Science, the University of Illinois at Urbana-Champaign, the Middle East Technical University in Turkey, and the University of Cambridge have designed a new material in which every atom is carefully laid out in its correct place, leading to a surprisingly high strength-to-weight ratio.

Woody metal

“The reason we call it metallic wood is not just its density, which is about that of wood, but its cellular nature,” says lead author James Pikul, Assistant Professor in the Department of Mechanical Engineering and Applied Mechanics at Penn Engineering.

“Cellular materials are porous; if you look at wood grain, that’s what you’re seeing — parts that are thick and dense and made to hold the structure, and parts that are porous and made to support biological functions, like transport to and from cells.”

The team writes that the material’s porous nature and the self-assembly process in which it’s created make it akin to wood and similar natural materials. Their metallic wood is made up of dense, strong metallic struts surrounding empty pores. The design operates “at the length scales where the strength of struts approaches the theoretical maximum,” Pikul explains.

Pikul’s team started with tiny plastic spheres of a few hundred nanometers in diameter, which they suspended in water. As the water slowly evaporated, the spheres stacked onto each other into an orderly, crystalline framework. The spheres were electroplated with nickel, then dissolved — leaving behind a network of metallic struts.

Material production process.

The fabrication process for a unit cell of the material. (b–g) Cross section SEM images of the (nickel inverse opal) material.

Each strut is around 10 nanometers wide, which is roughly the length of 100 nickel atoms, they explain. The team favored this production method over other techniques like 3D-printing as it’s easier to scale up.

“We’ve known that going smaller gets you stronger for some time,” Pikul says, “but people haven’t been able to make these structures with strong materials that are big enough that you’d be able to do something useful. Most examples made from strong materials have been about the size of a small flea, but with our approach, we can make metallic wood samples that are 400 times larger.”

“We’ve made foils of this metallic wood that are on the order of a square centimeter, or about the size of a playing die side,” he adds. “To give you a sense of scale, there are about 1 billion nickel struts in a piece that size.”

Because some 70% of the material is empty space, it has extremely low density in relation to its strength. It’s just a tad less dense than water, meaning a block of this material could float while still being stronger than most metal alloys today.

In a somewhat ironic twist, this process of creating metallic wood (which is metal in a wood-like configuration) is the opposite of how researchers at the University of Maryland created superdense wood (which is wood in a metal-like configuration).

The team is now focusing on expanding the production process to commercially relevant sizes. The materials used aren’t particularly rare or expensive on their own, but the infrastructure needed to carry out the production process is currently very limited. If that infrastructure is developed, however, the team is confident that their metallic wood can be produced more quickly and cheaply than their prototype sample.

A larger production base would also allow the team to further test their creation. Since they’ve only produced a tiny sample in the lab, the team is limited in what macroscale tests it can run on the material.

“We don’t know, for example, whether our metallic wood would dent like metal or shatter like glass.” Pikul says. “Just like the random defects in titanium limit its overall strength, we need to get a better understand of how the defects in the struts of metallic wood influence its overall properties.”

Another exciting possibility is merging the metallic wood with other materials to tailor it to a wide range of applications. Infusing it with anode and cathode materials, for example, would essentially turn the metallic wood into a very solid battery.

“The long-term interesting thing about this work is that we enable a material that has the same strength properties of other super high-strength materials but now it’s 70 percent empty space,” Pikul says.

“And you could one day fill that space with other things, like living organisms or materials that store energy.”

For example, the material could be used to produce smart prosthetics that store their own power — which would be pretty sweet.

The paper “High strength metallic wood from nanostructured nickel inverse opal materials” has been published in the journal Nature.

Scientists spot traces of titanium in scorching hot planet’s atmosphere

A team has now found evidence of iron and titanium vapors in the atmosphere of the hottest planet ever discovered.

Artistic depiction of KELT-9b orbiting its host star, KELT-9. Image credits: NASA/JPL-Caltech.

Planets don’t really get much hotter than KELT-9b. With a surface temperature well over 4,000 , the planet was detected in 2017 using the Kilodegree Extremely Little Telescope, and the unusual finding raised quite a few eyebrows at the time.

KELT-9, the star around which the planet revolves, is located some 650 light years from Earth, in the constellation Cygnus (the Swan). It’s twice as hot as the Sun, but that’s not the reason why planet KELT-9b is so hot.

The reason is the orbiting distance: located 30 times closer than the Earth’s distance from the Sun, the planet revolves around its star in only 36 hours. As a result, temperatures reach 4,600° Kelvin (4,300 °C / 7,800 °F). That’s not quite as hot as the Sun, but it’s definitely hotter than many stars.

Artistic depiction of KELT-9b. Image credits: Denis Bajram.

Astronomers aren’t really sure what the planet’s atmosphere might look like. Initial observations revealed that the atmosphere mostly comprises of hydrogen, but now, a new study has revealed some of its less abundant elements. Theoretical models suggested that metallic elements might be present in its atmosphere.

“The results of these simulations show that most of the molecules found there should be in atomic form because the bonds that hold them together are broken by collisions between particles that occur at these extremely high temperatures,” explains Kevin Heng, professor at the University of Bern.

Now, using the HARPS-North spectrograph, astronomers discovered a strong signal corresponding to iron vapor in the planet’s spectrum. They also found evidence of titanium in vapor form.

“With the theoretical predictions in hand, it was like following a treasure map,” says Jens Hoeijmakers, a researcher at the Universities of Geneva and Bern and lead author of the study, “and when we dug deeper into the data, we found even more,” he adds with a smile. Indeed, the team also detected the signature of another metal in vapur form: titanium.

This newly discovered planet might force scientists to open up a new planetary category: so-called “ultra-hot Jupiters.” Hot Jupiters are a class of gas giant exoplanets that are generally similar to Jupiter, but orbit much closer to their star — and are therefore much hotter. Ultra-hot Jupiters are even closer to their star

KELT-9b might not be the only planet to boast such an atmospheric composition. However, astronomers believe that planets like it, orbiting so close to their star, may be obliterated by the hellish environment in the star’s proximity. KELT-9b seems massive enough to take the pummeling, but others may have not been so fortunate.

Journal Reference: Hoeijmakers et al. Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b. Nature, 2018; DOI: 10.1038/s41586-018-0401-y

Titanium dioxide nanoparticles.

White paint might be causing a lot of Type 2 diabetes, preliminary research finds

A pilot study from The University of Texas at Austin suggests white paint and Type 2 diabetes might be linked.

Titanium dioxide nanoparticles.

Titanium dioxide nanoparticles.
Image credits University of Turin.

In the mid-20th century, titanium dioxide (TiO2) overthrew lead-based compounds (which were really toxic) as the go-to white pigment. Today, it’s the most widely used white pigment, mixed into everything from food and medication to plastic and paper. We rely on this substance a lot, as we’re producing in excess of 9 million metric tons of the stuff per year.

However, the pigment may not be as harmless as we’ve believed. Preliminary research has found TiO2 crystals embedded in pancreas tissue afflicted with Type 2 diabetes (T2D).

The white tint of diabetes

The team worked with 11 pancreas specimens, 8 from donors with T2D and 3 from donors who didn’t have the condition. The specimens were provided by the Juvenile Diabetes Research Foundation nPOD at the University of Florida at Gainesville.

The last three samples didn’t contain any detectable levels of TiO2 crystals. The 8 specimens with T2D, however, all had TiO2 crystals embedded in their tissues. The researchers report finding over 200 million TiO2 crystallites per gram of TiO2 particles in the specimens of donors with diabetes.

It’s particularly suspicious to find TiO2 crystals in all of the T2D specimens since titanium dioxide doesn’t have any known role in human biology. Furthermore, while plenty of different salts and other metallic compounds have a role to play in our bodies, there is no known role for titanium salt or another type of titanium compound in our biochemistry.

“Our initial findings raise the possibility that Type 2 diabetes could be a chronic crystal-associated inflammatory disease of the pancreas, similar to chronic crystal-caused inflammatory diseases of the lung such as silicosis and asbestosis,” said Adam Heller, the study’s lead author.

Heller is a professor in the McKetta Department of Chemical Engineering in the Cockrell School of Engineering. He has had a life-long career of diabetes research, for which he received the National Medal of Technology and Innovation in 2007.

Statistics from the World Health Organization show that the number of diabetes patients has quadrupled over the past four decades, reaching some 425 million known cases today. T2D represents the majority of these cases.

Although rising obesity rates and higher average life expectancy (which means more people reach old age) are considered the main factors driving this increase in T2D, the team isn’t convinced. Heller suggests that the increased use of titanium dioxide during these past few decades may be a key, if overlooked, driver of the condition.

“The increased use of titanium dioxide over the last five decades could be a factor in the Type 2 diabetes epidemic,” he said.

“The dominant T2D-associated pancreatic particles consist of TiO2 crystals, which are used as a colorant in foods, medications and indoor wall paint, and they are transported to the pancreas in the bloodstream. The study raises the possibility that humanity’s increasing use of TiO2 pigment accounts for part of the global increase in the incidence of T2D.”

The findings, right now, are far from convincing — but they are, potentially, very far-reaching. This was only a pilot study, with a very limited sample; Heller will repeat the study using a larger sample.

The paper “Association of Type 2 Diabetes with Submicron Titanium Dioxide Crystals in the Pancreas” has been published in the journal Chemical Research in Toxicology.

Chinese doctors replace woman’s vertebrae with 3D printed titanium implants

A Shanghai hospital reported the replacement of a highly complex cervical vertebra with 3D printed titanium implants.

Image via The Paper (cn).

The 28-year-old patient (who has not been named, going under the pseudonym of Xiao Wen) had been diagnosed with chondrosarcoma, one of the most dangerous and difficult to treat cancers. The tumor was located directly on her neck, expanding on six of the seven bones of the cervical vertebra. Chemotherapy and radiation are not very effective in most cases since there’s a good chance of the cancer returning, so doctors decided to remove the tumor.

Needless to say, that’s no easy feat.

Famed spinal surgeon Xiao Jianru and his team spent three weeks building artificial bones to replace her biological ones. Initially, they used imaging to create a life-size 3D printed model of the affected vertebrae and the tumor. They chose a titanium alloy and 3D printed it into the desired shape but even after the 14-centimeter (5.5-inch) bones were built, the outcome of the surgery was uncertain.

A 3D printed model (left), including the tumor (green) and the titanium replacement (right). Image via The Paper (cn).

Professor Xiao Jianru, an orthopedic surgeon with the hospital, said in a translated quote:

“The tumor volume is huge, the operation is extremely difficult, but still can be removed, we work together!”

The surgery took 13 grueling hours in total and was the first of its kind. At first, doctors carefully removed the cancerous vertebra, and then slowly replaced them with the bones they had created. Accomplishing all this without harming the patient was indeed a titanic work, made even more difficult by the patient’s physiology. Xiao Wen was overweight and had a short neck. The location of the tumor around the right cerebral artery and cervical nerve root was also particularly tricky.

Doctors were aware of dramatic potential complications: paralysis was on the list, as was overall dysfunction of the cervical spinal cord. But in the end, the procedure was successful. Xiao Wen woke up in control of her body and she can already walk, although she can’t comfortably turn her head around or move her neck. But in the grand scheme of things, that’s really not a concern.

Image via The Paper (cn).

It’s not the first time something like this was carried out at Shanghai Changzheng Hospital, one of the world’s largest centers for spinal tumor treatment. Just last year, Xiao’s team also used 3D printed technology to replace parts of a patient’s cervical vertebra and thoracic vertebra.

 

Blood, plasma and water droplets beading on a superomniphobic surface. Colorado State University researchers have created a titanium surface that's specifically designed to repel blood. (Credit: Kota Lab / Colorado State University)

Blood-repelling surface might finally put an end to clotting in medical implants

Blood, plasma and water droplets beading on a superomniphobic surface. Colorado State University researchers have created a titanium surface that's specifically designed to repel blood. (Credit: Kota Lab / Colorado State University)

Blood, plasma and water droplets beading on a superomniphobic surface. Colorado State University researchers have created a titanium surface that’s specifically designed to repel blood. (Credit: Kota Lab / Colorado State University)

Medical implant designers have always found it challenging to make their prostheses both biocompatible and safe from blood clotting. The solution might have been found at the interface between material science and biomedical engineering as Colorado State University engineers recently demonstrated. A team there designed a “superhemophobic” titanium surface that’s extremely repellent to blood. Tests ran in the lab suggest that blood would stay clear of an implant coated with this surface averting clots and infection that usually require doctors to perform surgery again.

Arun Kota and Ketul Popat, both from Colorado State University’s mechanical engineering and biomedical engineering departments, combined their expertise in an effort to design a surface that repels blood. Kota is an expert in superomniphobic materials (the kind that can repel virtually any liquid) while Popat’s work has been focused on tissue engineering and bio-compatible materials.

The two had to venture through unexplored terrain, as the typical approach has so far been the opposite. Medical implant engineers usually design “philic” surfaces that attract, not repel, blood so these are more biocompatible.

“What we are doing is the exact opposite,” Kota said. “We are taking a material that blood hates to come in contact with, in order to make it compatible with blood.”

That may sound confusing but the finished piece performed as intended. The researchers started with plain sheets of titanium whose surfaces they chemically altered to create a ‘phobic’ geometry onto which blood can’t come in contact with. It’s akin to how the lotus leaf repels water thanks to its nanoscale texture, only Kota and Popat’s surface was specially designed to repel blood. Experiments suggest very low levels of platelet adhesion, the biological process that eventually can lead to blood clotting and even biological rejection of the foreign material.

What the titanium's chemically altered surface looks like. The 'spikes' repel the blood. Credit: Colorado State Uni.

What the titanium’s chemically altered surface looks like. These ‘spikes’ repel the blood. Credit: Colorado State Uni.

Because the blood is ‘tricked’ that there is no surface blocking its flow, for all intents and purposes there is no foreign material.

“The reason blood clots is because it finds cells in the blood to go to and attach,” Popat said.

“Normally, blood flows in vessels. If we can design materials where blood barely contacts the surface, there is virtually no chance of clotting, which is a coordinated set of events. Here, we’re targeting the prevention of the first set of events.”

Next on the drawing board is to test new textures and chemistries. So far, fluorinated nanotubes seem to offer the best protection against clotting. Other clotting factors will also be examined and hopefully the Colorado State team may soon have the chance to test their work with real medical devices.

The findings were reported in the Advanced Healthcare Materials journal.

GeoPicture of the day: Titanium

titanium

Full resolution here – it works this time, I promise.

Believe it or not, this is actually titanium, though not natural. It was obtained through a process called iodide process (or crystal bar process), unlike natural titanium, which is usually found chemically bonded in various ways found in rock ores. For more information, you should really check out this video (it’s actually a series with many other ones).

Computer model, next to the finished part of the lower jaw. (c) Layerwise

Surgery replaces woman’s jaw with a 3D printed titanium one

Hailed as a breakthrough in reconstructive surgery, an 83-year old woman had her lower jaw replaced by an exact 3D printed replica made out of titanium. The implant was made by heating and fusing together titanium ore, one layer at a time with a laser. The procedure took place last summer in the Netherlands, but only recently became public.

Computer model, next to the finished part of the lower jaw. (c) Layerwise

Computer model, next to the finished part of the lower jaw. (c) Layerwise

Usually, reconstructive surgery, such as the one the elderly woman would have had to go through were it not for this alternative, is extremely complex and laborious, typically requiring 20 hours of surgery, coupled with up to four weeks of hospitalization. Due to her old age, this was dubbed too risky, and instead the surgeons at the Biomedical Research Institute at Hasselt University in Belgium decided to opt for this innovative and novel technology.

After the design of the jaw was delivered as an exact replica of the one to be replaced, it only took a few hours for it to be printed, as a laser fussed thousands of layers together. The implant mimics all the complex feature of the original lower jaw – articulated joints, cavities to promote muscle attachment and grooves to direct the regrowth of nerves and veins. After the print was ready, it was given a bioceramic coating. At the end, it only weighed 30 grams more than the original bone structure.

It only took a few hours of surgery and four days of hospital care, a fifth of the current required recovery time. A follow-up procedure will commence soon, as doctors need to remove healing implants inserted into holes built into the implant’s surface and attach a dental bridge, such that fake teeth can be screwed on to provide a set of dentures.

“Shortly after waking up from the anaesthetics the patient spoke a few words, and the day after the patient was able to swallow again,” said Dr Jules Poukens from Hasselt University, who led the surgical team.

“The new treatment is a world premiere because it concerns the first patient-specific implant in replacement of the entire lower jaw.”

This remarkable breakthrough only goes to show how 3D printing can grow to become indispensable to surgery in the future. Broken limbs, entire structures that need to be replaced, can be fully customized and replaced easily. The reduced waiting time as a result of reduced procedure time, means that even more people can now benefit from surgeries faster, reducing risks and allowing them to return to their families a lot sooner. And these are just bones.

LayerWise, a specialized metal-parts manufacturer, which offered the necessary technology to 3D print the jaw, claims that print body organs ready for transplant, however such a feat might not be possible during our lifetimes.

“There are still big biological and chemical issues to be solved,” said Ruben Wauthle, LayerWise’s medical applications engineer,.

“At the moment we use metal powder for printing. To print organic tissue and bone you would need organic material as your ‘ink’. Technically it could be possible – but there is still a long way to go before we’re there.”

Moon Express' lunar lander, depicted here as an artist's impression. (c) Moon Express inc.

Mining the moon: an entrepreneur’s vision

Moon Express' lunar lander, depicted here as an artist's impression. (c) Moon Express inc.

Moon Express' lunar lander, depicted here as an artist's impression. (c) Moon Express inc.

While the Earth is steadily being depleted of its natural resources, it might become imperative to look to the sky for alternatives. Studies so far alone has shown that the moon has twenty times more titanium and platinum than anywhere on Earth, along with helium 3, a rare isotope of helium, which is nonexistent on our planet, that many feel could be the future of energy on Earth and in space.

Even though it may seem that space exploration has been set up a huge step back after NASA retired its shuttle program, the future might be a highly bright one thanks to privatized space programs. Naveen Jain, co-founder and chairman of Moon Express, Inc., is one of the couple of billionaires today who share a common vision – the future of private space capitalization. Jain’s idea, in particular, is that of bringing lunar landers and mining platforms to the moon.

“People ask, why do we want to go back to the moon? Isn’t it just barren soil?” Jain said. “But the moon has never been explored from an entrepreneurial perspective.”

He actually sees a lot of opportunities with lunar exploration, besides mining.

“No one has ever captured people’s fascination with the moon,” he said. “What if, say, we take a picture of your family on the moon and project it back to you? Or take DNA up there?”

So far, this company Moon Express has already been awarded $10 million by NASA, part of the agency’s Innovative Lunar Demonstration Data (ILDD) program, and is also shooting for the $30 million put into play by Google’s Lunar X Prize. Jain, a self-made billionaire, is confident that by 2013 his company will commence the first mining operations on the moon. So far, MoonEx’s lunar lander successfully completed a flight test at the Hover Test Facility in NASA’s Ames Research Center

“Perpetual ownership of private or government assets in space or on other bodies is a well defined, documented and practiced aspect of the 1967 Outer Space Treaty,” explained company CEO Bob Richards in a recent blog post.

You might think that mining on the moon would be a at least ten times more expensive than mining on Earth, no matter how precious that material might be, but according to MoonEx officials the difficult part is only setting-up an initial infrastructure. From the moon, ore or helium3, might be easily transported by putting it into orbit, where it would be collected and delivered on Earth using solar sails.

“We want to solve the problem of energy on Earth by using the moon as the eighth continent”