Nanostructured High-Strength LightWeight Concrete

Scientists from the Peter the Great Saint-Petersburg Polytechnic University (SPbPU) in Russia, have created several types of building blocks based on nanostructured high-strength lightweight concrete, reinforced with skew-angular composite coarse grids. The development has unique characteristics, enabling the increase of load-carrying capability by more than 200% and decrease in specific density of the construction by 80%. In addition, among the advantages, are resistance to corrosion, aggressive environments and excessive frost resistance.

Researchers calculated that the service life of the building structures, made with the use of this reinforcement system, will increase at least 2-3 times in comparison with its modern analogs.

Such system allows to ensure the structure integrity even in conditions of seismic activity, since the load is distributed throughout the structure as a whole, and not by individual reinforcement bars. The invention can be used in the construction of bridges and pedestrian crossings, non-metallic ships, low-rise residential buildings” says Alexander Rassokhin, graduate student at SPbPU. Andrey Ponomarev, Professor of the Institute of Civil Engineering is the co-inventor of the new  construction technology.

The fundamentals of the research have been described in an article “Hybrid wood-polymer composites in civil engineering” at the Magazine of Civil Engineering.


How To Harness Heat To Power Computers

One of the biggest problems with computers, dating to the invention of the first one, has been finding ways to keep them cool so that they don’t overheat or shut down. Instead of combating the heat, two University of Nebraska–Lincoln engineers have embraced it as an alternative energy source that would allow computing at ultra-high temperatures. Sidy Ndao, assistant professor of mechanical and materials engineering, said his research group’s development of a nano-thermal-mechanical device, or thermal diode, came after flipping around the question of how to better cool computers.

thermal diode

If you think about it, whatever you do with electricity you should (also) be able to do with heat, because they are similar in many ways,” Ndao said. “In principle, they are both energy carriers. If you could control heat, you could use it to do computing and avoid the problem of overheating.”

A paper Ndao co-authored with Mahmoud Elzouka, a graduate student in mechanical and materials engineering, was published in the March edition of Scientific Reports. In it, they documented their device working in temperatures that approached 630 degrees Fahrenheit (332 degrees Celsius).


Efficient, Fast, Large-scale 3-D Manufacturing

Washington State University (WSU) researchers have developed a unique, 3-D manufacturing method that for the first time rapidly creates and precisely controls a material’s architecture from the nanoscale to centimeters – with results that closely mimic the intricate architecture of natural materials like wood and bone.

3D manufacturing Hex-Scaffold-web-

This is a groundbreaking advance in the 3-D architecturing of materials at nano- to macroscales with applications in batteries, lightweight ultrastrong materials, catalytic converters, supercapacitors and biological scaffolds,” said Rahul Panat, associate professor in the School of Mechanical and Materials Engineering, who led the research. “This technique can fill a lot of critical gaps for the realization of these technologies.”

The WSU research team used a 3-D printing method to create foglike microdroplets that contain nanoparticles of silver and to deposit them at specific locations. As the liquid in the fog evaporated, the nanoparticles remained, creating delicate structures. The tiny structures, which look similar to Tinkertoy constructions, are porous, have an extremely large surface area and are very strong.

The researchers would like to use such nanoscale and porous metal structures for a number of industrial applications; for instance, the team is developing finely detailed, porous anodes and cathodes for batteries rather than the solid structures that are now used. This advance could transform the industry by significantly increasing battery speed and capacity and allowing the use of new and higher energy materials.

They report on their work in the journal  Science Advances  and have filed for a patent.


Breakthrough In The BioMedical Industry

Polyhedral boranes, or clusters of boron atoms bound to hydrogen atoms, are transforming the biomedical industry. These manmade materials have become the basis for the creation of cancer therapies, enhanced drug delivery and new contrast agents needed for radioimaging and diagnosis. Now, a researcher at the University of Missouri has discovered an entirely new class of materials based on boranes that might have widespread potential applications, including improved diagnostic tools for cancer and other diseases as well as low-cost solar energy cells.

Mark Lee Jr., an assistant professor of chemistry in the MU College of Arts and Science, discovered the new class of hybrid nanomolecules by combining boranes with carbon and hydrogen. Boranes are chemically stable and have been tested at extreme heat of up to 900 degrees Celsius or 1,652 degrees Fahrenheit. It is the thermodynamic stability these molecules exhibit that make them non-toxic and attractive to the biomedical, personal computer and alternative energy industries.
Polyhedral boranes

Despite their stability, we discovered that boranes react with aromatic hydrocarbons at mildly elevated temperatures, replacing many of the hydrogen atoms with rings of carbon,” Lee said. “Polyhedral boranes are incredibly inert, and it is their reaction with aromatic hydrocarbons like benzene that will make them more useful.”

Lee also showed that the attached hydrocarbons communicate with the borane core. “The result is that these new materials are highly fluorescent in solution,” Lee said. “Fluorescence can be used in applications such as bio-imaging agents and organic light-emitting diodes like those in phones or television screens. Solar cells and other alternative energy sources also use fluorescence, so there are many practical uses for these new materials.
The findings have been recently published in the international journal Angewandte Chemie.


How To Convert Heat Into Electricity

The same researchers who pioneered the use of a quantum mechanical effect to convert heat into electricity have figured out how to make their technique work in a form more suitable to industry. In Nature Communications, engineers from The Ohio State University (OSU) describe how they used magnetism on a composite of nickel and platinum to amplify the voltage output 10 times or more—not in a thin film, as they had done previously, but in a thicker piece of material that more closely resembles components for future electronic devices.

Many electrical and mechanical devices, such as car engines, produce heat as a byproduct of their normal operation. It’s called “waste heat,” and its existence is required by the fundamental laws of thermodynamics, explained study co-author Stephen Boona.

devices-that-convert-heat-into-electricityOver half of the energy we use is wasted and enters the atmosphere as heat,” said Boona, a postdoctoral researcher at Ohio State. “Solid-state thermoelectrics can help us recover some of that energy. These devices have no moving parts, don’t wear out, are robust and require no maintenance. Unfortunately, to date, they are also too expensive and not quite efficient enough to warrant widespread use. We’re working to change that.”But a growing area of research called solid-state thermoelectrics aims to capture that waste heat inside specially designed materials to generate power and increase overall energy efficiency.


Self-Healable Lithium Ion Battery For Electronic Textile

Electronics that can be embedded in clothing are a growing trend. However, power sources remain a problem. In the journal Angewandte Chemie, scientists have now introduced thin, flexible, lithium ion batteries with self-healing properties that can be safely worn on the body. Even after completely breaking apart, the battery can grow back together without significant impact on its electrochemical properties.

Existing lithium ion batteries for wearable electronics can be bent and rolled up without any problems, but can break when they are twisted too far or accidentally stepped on—which can happen often when being worn. This damage not only causes the battery to fail, it can also cause a safety problem: Flammable, toxic, or corrosive gases or liquids may leak out.

A team led by Yonggang Wang and Huisheng Peng from  Fudan University in Shanghai – China, has now developed a new family of lithium ion batteries that can overcome such accidents thanks to their amazing self-healing powers. In order for a complicated object like a battery to be made self-healing, all of its individual components must also be self-healing. The scientists from Fudan University  the Samsung Advanced Institute of Technology (South Korea), and the Samsung R&D Institute China, have now been able to accomplish this.

self-healing-batteryThe electrodes in these batteries consist of layers of parallel carbon nanotubes. Between the layers, the scientists embedded the necessary lithium compounds in nanoparticle. In contrast to conventional lithium ion batteries, the lithium compounds cannot leak out of the electrodes, either while in use or after a break. The thin layer electrodes are each fixed on a substrate of self-healing polymer. Between the electrodes is a novel, solvent-free electrolyte made from a cellulose-based gel with an aqueous lithium sulfate solution embedded in it. This gel electrolyte also serves as a separation layer between the electrodes.

After a break, it is only necessary to press the broken ends together for a few seconds for them to grow back together. Both the self-healing polymer and the carbon nanotubes “stick” back together perfectly. The parallel arrangement of the nanotubes allows them to come together much better than layers of disordered carbon nanotubes. The electrolyte also poses no problems. Whereas conventional electrolytes decompose immediately upon exposure to air, the new gel is stable. Free of organic solvents, it is neither flammable nor toxic, making it safe for this application.

The capacity and charging/discharging properties of a batteryarmband” placed around a doll’s elbow were maintained, even after repeated break/self-healing cycles.


Nanotechnologies Crush the Road Construction Costs

The solution for affordable road infrastructure development could lie in the use of nanotechnology, according to a paper presented at the 35th annual Southern African Transport Conference in Pretoria. The cost of upgrading, maintaining and rehabilitating road infrastructure with limited funds makes it impossible for sub-Saharan Africa to become competitive in the world market, according to Professor Gerrit Jordaan of the University of Pretoria, a speaker at the conference. The affordability of road infrastructure depends on the materials used, the environment in which the road will be built and the traffic that will be using the road, explained Professor James Maina of the department of civil engineering at the University of Pretoria. Hauling materials to a construction site contributes hugely to costs, which planners try to minimise by getting materials closer to the site. But if there aren’t good quality materials near the site, another option is to modify poor quality materials for construction purposes. This is where nanotechnology comes in.


Nanomaterial is really small; five nanometers are equivalent to 0.05mm,” explained Maina. The materials bind with the poor quality material which needs to be modified, and can then change the behaviour of the material.

For example, if the material is clay soil, it has a high affinity to water so when it absorbs water it expands, and when it dries out it contracts. Nanotechnology can make the soil water repellent. “Essentially, nanotechnology changes the properties to work for the construction process,” he said.

These nanotechnology-based products have been used successfully in many parts of the world, including India, the USA and in the West African region.
“We need to have roads to enable mass movement of people and goods,” said Maina. Well-maintained road infrastructure ensures optimal speed of movement, opening up economic opportunities for people. Moving goods safely is also important as damaged goods translate into economic cost, he explained. “For a country to be competitive globally, we need to reduce costs as much as possible. We need well maintained and well planned road infrastructure,” comments Maina.


Bones and Shells, Inspiration For New Materials

Researchers at MIT are seeking to redesign concrete — the most widely used human-made material in the world — by following nature’s blueprints. In a paper published online in the journal Construction and Building Materials, the team contrasts cement pasteconcrete’s binding ingredient — with the structure and properties of natural materials such as bones, shells, and deep-sea sponges. As the researchers observed, these biological materials are exceptionally strong and durable, thanks in part to their precise assembly of structures at multiple length scales, from the molecular to the macro, or visible, level.

From their observations, the team, led by Oral Buyukozturk, a professor in MIT’s Department of Civil and Environmental Engineering (CEE), proposed a new bioinspired, “bottom-upapproach for designing cement paste.

bones molecular structure

These materials are assembled in a fascinating fashion, with simple constituents arranging in complex geometric configurations that are beautiful to observe,” Buyukozturk says. “We want to see what kinds of micromechanisms exist within them that provide such superior properties, and how we can adopt a similar building-block-based approach for concrete.”

Ultimately, the team hopes to identify materials in nature that may be used as sustainable and longer-lasting alternatives to Portland cement, which requires a huge amount of energy to manufacture. “If we can replace cement, partially or totally, with some other materials that may be readily and amply available in nature, we can meet our objectives for sustainability,” Buyukozturk says.


New Efficient Materials For Solar Fuel Cells

University of Texas at Arlington (UTA) chemists have developed new high-performing materials for cells that harness sunlight to split carbon dioxide and water into useable fuels like methanol and hydrogen gas. These “green fuels” can be used to power cars, home appliances or even to store energy in batteries.

solar fuel cells

Technologies that simultaneously permit us to remove greenhouse gases like carbon dioxide while harnessing and storing the energy of sunlight as fuel are at the forefront of current research,” said Krishnan Rajeshwar, UTA distinguished professor of chemistry and biochemistry and co-founder of the University’s Center of Renewable Energy, Science and Technology. “Our new material could improve the safety, efficiency and cost-effectiveness of solar fuel generation, which is not yet economically viable,” he added.

The new hybrid platform uses ultra-long carbon nanotube networks with a homogeneous coating of copper oxide nanocrystals. It demonstrates both the high electrical conductivity of carbon nanotubes and the photocathode qualities of copper oxide, efficiently converting light into the photocurrents needed for the photoelectrochemical reduction process. Morteza Khaledi, dean of the UTA College of Science, said Rajeshwar’s work is representative of the University’s commitment to addressing critical issues with global environmental impact under the Strategic Plan 2020.


Revolution In The Nanotechnology Industry

After six years of painstaking effort, a group of University of Wisconsin-Madison (UW-Madison) materials scientists believe their breakthrough in growing tiny sheets of zinc oxide could have huge implications for the future of nanomaterial manufacturing—and in turn, on a host of electronic and biomedical devices.
The group, led by Xudong Wang, an associate professor of science and engineering at UW-Madison, and postdoctoral researcher Fei Wang, has developed a novel technique for synthesizing two-dimensional nanosheets from compounds that do not naturally form the atomic-layer-thick materials. Essentially the microscopic equivalent of a single sheet of paper, a 2D nanosheet is a material that is constrained to up to only a few atomic layers in one direction. Nanomaterials—materials that are constrained in at least one dimension to a maximum of a handful of atomic layers—have unique physical properties that alter their electronic and chemical properties in relation to their compositionally identical but conventional, and larger, material counterparts.


What’s nice with a 2D nanomaterial is that because it’s a sheet, it’s much easier for us to manipulate compared to other types of nanomaterials,” says Xudong Wang. Xudong Wang first had the idea for using a surfactant to grow nanosheets during a lecture he was giving in a course on nanotechnology in 2009. “The course includes a lecture about self-assembly of monolayers,” adds Xudong Wang. “Under the correct conditions, a surfactant will self-assemble to form a monolayer. This is a well-known process that I teach in class. So while teaching this I wondered why we wouldn’t be able to reverse this method and use the surfactant monolayer first to grow the crystalline face.

It is the first time such a technique has been successful, and the researchers described their findings in the journal Nature Communications.


Super-Strong, Light New Metal For Airplanes, Cars

team led by researchers from the Univeristy of California Los Angleles (UCLA) Henry Samueli School of Engineering and Applied Science has created a super-strong yet light structural metal with extremely high specific strength and modulus, or stiffness-to-weight ratio. The new metal is composed of magnesium infused with a dense and even dispersal of ceramic silicon carbide nanoparticles. It could be used to make lighter airplanes, spacecraft, and cars, helping to improve fuel efficiency, as well as in mobile electronics and biomedical devices.

To create the super-strong but lightweight metal, the team found a new way to disperse and stabilize nanoparticles in molten metals. They also developed a scalable manufacturing method that could pave the way for more high-performance lightweight metals.

strong metalAt left, a deformed sample of pure metal; at right, the strong new metal made of magnesium with silicon carbide nanoparticles. Each central micropillar is about 4 micrometers across.

It’s been proposed that nanoparticles could really enhance the strength of metals without damaging their plasticity, especially light metals like magnesium, but no groups have been able to disperse ceramic nanoparticles in molten metals until now,” said Xiaochun Li, the principal investigator on the research and Raytheon Chair in Manufacturing Engineering at UCLA. “With an infusion of physics and materials processing, our method paves a new way to enhance the performance of many different kinds of metals by evenly infusing dense nanoparticles to enhance the performance of metals to meet energy and sustainability challenges in today’s society.

The research has been  published  in Nature.


So Strong And Thousands Of Times Thinner Than A Sheet Of Paper

Scientists and engineers are engaged in a global race to make new materials that are as thin, light and strong as possible. These properties can be achieved by designing materials at the atomic level, but they are only useful if they can leave the carefully controlled conditions of a lab. Researchers at the University of Pennsylvania have now created the thinnest plates that can be picked up and manipulated by hand. Despite being thousands of times thinner than a sheet of paper and hundreds of times thinner than household cling wrap or aluminum foil, their corrugated plates of aluminum oxide spring back to their original shape after being bent and twisted.


The researchers’ plates are strong enough to be picked up by hand and retain their shape after being bent and squeezed
Like cling wrap, comparably thin materials immediately curl up on themselves and get stuck in deformed shapes if they are not stretched on a frame or backed by another material.

Being able to stay in shape without additional support would allow this material, and others designed on its principles, to be used in aviation and other structural applications where low weight is at a premium.