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NIST 580303_10152072709285365_1905986131_n The National Institute of Standards and Technology (NIST) has put firm numbers on the high costs of installing pipelines to transport hydrogen fuel–and also found a way to reduce those costs.

Samples of pipeline steel instrumented for fatigue testing in a pressurized hydrogen chamber (the vertical tube). NIST researchers used data from such tests to develop a model for hydrogen effects on pipeline lifetime, to support a federal effort to reduce overall costs of hydrogen fuel. (Image: NIST)
Pipelines to carry hydrogen cost more than other gas pipelines because of the measures required to combat the damage hydrogen does to steel’s mechanical properties over time. NIST researchers calculated that hydrogen-specific steel pipelines can cost as much as 68 percent more than natural gas pipelines, depending on pipe diameter and operating pressure.* By contrast, a widely used cost model** suggests a cost penalty of only about 10 percent.>Samples of pipeline steel instrumented for fatigue testingBut the good news, according to the new NIST study, is that hydrogen transport costs could be reduced for most pipeline sizes and pressures by modifying industry codes*** to allow the use of a higher-strength grade of steel alloy without requiring thicker pipe walls. The stronger steel is more expensive, but dropping the requirement for thicker walls would reduce materials use and related welding and labor costs, resulting in a net cost reduction. The code modifications, which NIST has proposed to the American Society of Mechanical Engineers (ASME), would not lower pipeline performance or safety, the NIST authors say.”The cost savings comes from using less–because of thinner walls–of the more expensive material,” says NIST materials scientist James Fekete, a co-author of the study. “The current code does not allow you to reduce thickness when using higher-strength material, so costs would increase. With the proposed code, in most cases, you can get a net savings with a thinner pipe wall, because the net reduction in material exceeds the higher cost per unit weight.”

The NIST study is part of a federal effort to reduce the overall costs of hydrogen fuel, which is renewable, nontoxic and produces no harmful emissions. Much of the cost is for distribution, which likely would be most economical by pipeline. The U.S. contains more than 300,000 miles of pipelines for natural gas but very little customized for hydrogen. Existing codes for hydrogen pipelines are based on decades-old data. NIST researchers are studying hydrogen’s effects on steel to find ways to reduce pipeline costs without compromising safety or performance.

As an example, the new code would allow a 24-inch pipe made of high-strength X70 steel to be manufactured with a thickness of 0.375 inches for transporting hydrogen gas at 1500 pounds per square inch (psi). (In line with industry practice, ASME pipeline standards are expressed in customary units.) According to the new NIST study, this would reduce costs by 31 percent compared to the baseline X52 steel with a thickness of 0.562 inches, as required by the current code. In addition, thanks to its higher strength, X70 would make it possible to safely transport hydrogen through bigger pipelines at higher pressure (36-inch diameter pipe to transport hydrogen at 1500 psi) than is allowed with X52, enabling transport and storage of greater fuel volumes. This diameter-pressure combination is not possible under the current code.

The proposed code modifications were developed through research into the fatigue properties of high-strength steel at NIST’s Hydrogen Pipeline Material Testing Facility. In actual use, pipelines are subjected to cycles of pressurization at stresses far below the failure point, but high enough to result in fatigue damage. Unfortunately, it is difficult and expensive to determine steel fatigue properties in pressurized hydrogen. As a result, industry has historically used tension testing data as the basis for pipeline design, and higher-strength steels lose ductility in such tests in pressurized hydrogen. But this type of testing, which involves steadily increasing stress to the failure point, does not predict fatigue performance in hydrogen pipeline materials, Fekete says.
NIST research has shown that under realistic conditions, steel alloys with higher strengths (such as X70) do not have higher fatigue crack growth rates than lower grades (X52). The data have been used to develop a model**** for hydrogen effects on pipeline steel fatigue crack growth, which can predict pipeline lifetime based on operating conditions.
Notes
* J.W. Sowards, J.R. Fekete and R.L. Amaro. Economic impact of applying high strength steels in hydrogen gas pipelines. International Journal of Hydrogen Energy. 2015. In press, corrected proof available online. DOI:10.1016/j.ijhydene.2015.06.090
** DOE H2A Delivery Analysis. U.S. Department of Energy. Available online at www.hydrogen.energy.gov/h2a_delivery.html.
*** ASME B31.12 Hydrogen Piping and Pipeline Code (ASME B31.12). Industry groups such as ASME commonly rely on NIST data in developing codes.
**** R.L. Amaro, N. Rustagi, K.O. Findley, E.S. Drexler and A.J. Slifka. Modeling the fatigue crack growth of X100 pipeline steel in gaseous hydrogen. Int. J. Fatigue, 59 (2014). pp 262-271.
Source: NIST

Super Cooled Drug 050815 asupercoolwa Source: American Friends of Tel Aviv University

Summary: Some substances, when they undergo a process called ‘rapid-freezing’ or ‘supercooling,’ remain in liquid form — even at below-freezing temperatures. A new study is the first to break down the rules governing the complex process of crystallization through rapid-cooling.

Its findings may revolutionize the delivery of drugs in the human body, providing a way to ‘freeze’ the drugs at an optimal time and location in the body.

Water, when cooled below 32°F, eventually freezes — it’s science known even to pre-schoolers. But some substances, when they undergo a process called “rapid-freezing” or “supercooling,” remain in liquid form — even at below-freezing temperatures.

The supercooling phenomenon has been studied for its possible applications in a wide spectrum of fields. A new Tel Aviv University study published in Scientific Reports is the first to break down the rules governing the complex process of crystallization through rapid-cooling. According to the research, membranes can be engineered to crystallize at a specific time. In other words, it is indeed possible to control what was once considered a wild and unpredictable process — and it may revolutionize the delivery of drugs in the human body, providing a way to “freeze” the drugs at the exact time and biological location in the body necessary.

The study was led jointly by Dr. Roy Beck of the Department of Physics at TAU’s School of Physics and Astronomy and Prof. Dan Peer of the Department of Cell Research and Immunology at TAU’s Faculty of Life Sciences, and conducted by TAU graduate students Guy Jacoby, Keren Cohen, and Kobi Barkai.

Controlling a metastable process

“We describe a supercooled material as ‘metastable,’ meaning it is very sensitive to any external perturbation that may transform it back to its stable low-temperature state,” Dr. Beck said. “We discovered in our study that it is possible to control the process and harness the advantages of the fluid/not-fluid transition to design a precise and effective nanoscale drug encapsulating system.”

For the purpose of the study, the researchers conducted experiments on nanoscale drug vesicles (fluid-filled sacs that deliver drugs to their targets) to determine the precise dynamics of crystallization. The researchers used a state-of-the-art X-ray scattering system sensitive to nanoscale structures.

“One key challenge in designing new nano-vesicles for drug delivery is their stability,” said Dr. Beck. “On the one hand, you need a stable vesicle that will entrap your drug until it reaches the specific diseased cell. But on the other, if the vesicle is too stable, the payload may not be released upon arrival at its target.”

“Supercooled material is a suitable candidate since the transition between liquid and crystal states is very drastic and the liquid membrane explodes to rearrange as crystals. Therefore this new physical insight can be used to release entrapped drugs at the target and not elsewhere in the body’s microenvironment. This is a novel mechanism for timely drug release.”

All in the timing

The researchers found that the membranes were able to remain stable for tens of hours before collectively crystallizing at a predetermined time.

“What was amazing was our ability to reproduce the results over and over again without any complicated techniques,” said Dr. Beck. “We showed that the delayed crystallization was not sensitive to minor imperfection or external perturbation. Moreover, we found multiple alternative ways to ‘tweak the clock’ and start the crystallization process.”

The researchers are investigating an appropriate new nano-capsule capable of releasing medication at a specific time and place in the body. “The challenge now is to find the right drugs to exploit our insights for the medical benefit of patients,” said Dr. Beck.


Story Source:

The above story is based on materials provided by American Friends of Tel Aviv University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Guy Jacoby, Keren Cohen, Kobi Barkan, Yeshayahu Talmon, Dan Peer, Roy Beck. Metastability in lipid based particles exhibits temporally deterministic and controllable behavior. Scientific Reports, 2015; 5: 9481 DOI: 10.1038/srep09481

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