Industry Insights Series: David Fry

Working alongside our friends at AZOM, they developed a series of engaging interviews with a few of our global colleagues. In the recent series, I was able to discuss metals testing requirements with a focus on the latest European metals standard, ISO 6892 and high precision strain measurement with the AutoX750.

We'd appreciate hearing from you some suggestions for additional interview topics that would benefit your testing and applications. Read more

Instron at Tissue Engineering Conference in Istanbul

 

Instron TGT went on the road for the TERMIS (Tissue Engineering and Regenerative Medicine International Society) meeting in Istanbul, Turkey at the end of June. Despite the "social unrest" in Istanbul, the conference was well attended with over 500 attendees from around the world, including Argentina, Chile, Korea, Russia, and New Zealand.

We introduced our combination of products, with a demonstration of the 5944 and Bluehill^® and the LigaGen Bioreactor System. The attendees were excited to learn about the acquisition and the new solutions that Instron could provide to tissue engineering and regenerative medicine. We estimate that 30—40% of the researchers were familiar with Instron, including those already using Instron systems to characterize materials for tissue engineering or to test and characterize tissue engineered products.

Tissue engineering conferences are an exciting combination of disciplines and this one was no exception. An array of topics were covered, ranging from Biomaterials; Scaffold Designs and Fabrication Techniques; Tissues & Cells; Stem Cell Science; Genetic Modifications; and Bioreactors.

We look forward to attending the remaining 2013 regional meetings in Shanghai (October 23—26) and Atlanta, GA (November 10—13).

Want to know what tissue engineering and regenerative medicine is all about? Check out Dr. Atala's TED talk on bioengineered tissues. Read more

Equipment Considerations for a Well-aligned Test

When testing stiff or brittle materials, such as composites, alignment is crucial—even instances of slight misalignment can throw off test results.

Misalignment in test frames takes two forms: concentricity misalignment, where the centerline of the upper grip/fixture is offset from the centerline of the lower grip/fixture, and angularity misalignment, where the two centerlines are at contrasting angles. Both forms cause extra stress on the specimen and can affect mechanical properties such as modulus, maximum elongation, and tensile strength.

The alignment of a system is so critical to test results that organizations, such as Nadcap, strictly regulate misalignment. To meet these requirements and reach the most accurate results, the test operator needs to carefully assess his or her station, including the testing frame itself to the alignment cells used to verify alignment.

In addition to being accurately aligned, the frame should also be stiff so that it deflects very little at the load.

Next, it’s necessary to align the frame with the grips that will actually be used. This means that if an alignment is performed with one set of grips, but then replaced with a second set of grips, both sets of grips must be realigned. (To prevent removing grips, it is helpful to choose grips that can accommodate multiple tests including compression.)

Rigid and symmetrical grips produce the best alignment results. Under load, symmetrical grips will deform symmetrically from front-to-back/from side-to-side; therefore, the grips will not bend the specimen. Plus, the more rigid a grip is the less it will deform under load.

Once the frame and grips are aligned, now the specimen needs to be aligned. The operator oversees this process. To minimize user error, grips with specimen stops indicate where to place the specimen every time. If the specimen is loaded in different positions, even in a perfectly aligned system, large variation will occur.

To ensure that platens are parallel to the degree that Nadcap requires, one rigid platen and one locking, spherically-seated platen are required. These types of platen can be compressed against each other to ensure that they are parallel and can then be locked to prevent them from being misaligned.

Alignment cells are an essential part of any alignment. These cells, when used in conjunction with software, provide valuable information on how to correct a system’s misalignment. The dimensions of the cell should be as close as possible to the specimens being tested. On occasion, standard or stock alignment cells do not fit with the samples being tested. In these instances, the design of a custom strain-gaged alignment cell may be necessary. Since fabricating a strain-gaged alignment transducer can be a time-consuming process, plan this step well in advance.

Any given system has small misalignment errors due to tolerances of the frame and the parts used. To adjust for these small errors, it is helpful to have a fixture which can be used to make small adjustments to the concentricity and angularity of the load string. This is especially handy for future alignments and will save you time and effort down the road.

As always, feel free to contact us with any questions. Read more

Question from a Customer: Bagley Correction

Question:
Can we compare viscosity results between polymers tested at the same temperature and identical shear rates but on two different capillary rheometers?

Answer:
As an example, let’s consider two capillary rheometers with the following specifications and test parameters.

Rheometer A:
Barrel diameter = 9.55 mm
Capillary diameter = 20 mm
Capillary length = 1 mm
Test temperature = 150 C
Shear rates = 100, 200, 300, 400, 500 1/s

Rheometer B:
Barrel diameter = 15 mm
Capillary diameter = 10 mm
Capillary length = 1 mm
Test temperature = 150 C
Shear rates = 100, 200, 300, 400, 500 1/s

Results obtained from a single test performed each on Rheometer A and Rheometer B are generally not comparable.

In order to compare any number of viscosity results from two or more different capillary rheometers, it is very important to normalize the pressure data by introducing a correction called Bagley Correction post testing. This correction applied to the pressure data will generate true viscosity values which will then be comparable between different capillary rheometers. This correction is necessary because of the “entrance effects”, which occur when the molten polymer is pushed through the larger barrel diameter into the smaller capillary diameter. These “entrance effects” generally are different between Rheometers A and B. The Bagley Correction compensates for these differences, thereby making the results between the two comparable. To find out more about the Bagley Correction, and how to apply it, please refer to this blog post. Read more

Instron at Alabama Composites Conference, Birmingham

Instron was at the Alabama Composites Conference (ACC) from June 19—20 in Birmingham, Alabama. Southeast Applications Engineer Jim Gleason and Kent Wallace, Dynamic Systems, were on site. ACC is held every two years at the University of Birmingham, Alabama (UAB) and focuses on latest innovations in the composites industry. Instron is proud to support such an event because it sees participation from a wide range of industry partners working with composite materials.

We exhibited an ElectroPuls E1000 and had a few Instron personnel at ACC to give information about our other product lines like electromechanical systems, CEAST impact machines, hydraulic systems, etc.

Check this out for an array of topics covered during different sessions of this conference. I found the ENERGY, GREEN, and BIOCOMPOSITES section very interesting in terms of using natural fibers as reinforcements to the matrix.

Read more

A New Long-Term Bypass Solution

Today, heart disease is so common that it’s a fair statement to make that you or someone you know has been affected by this illness. It’s estimated that more than 17 million people around the world lose their lives to heart disease every year, according to the World Health Organization. And in the US alone, more than 500,000 of those patients undergo bypass surgery. Most surgeons will “borrow” blood vessels from another part of the patient, such as the mammary artery or saphenous vein; another option is to use a prosthetic graft material. Tissue Engineering will soon provide the superior option, replacement parts made from the patient’s own cells.

While prosthetic and “borrowing” the patient’s veins are popular and familiar choices amongst bypass patients, there is risk involved. The prosthetic grafts have the chance of rejection by the body because they are not natural and are foreign to the body.  Also, the plastic material has been shown to increasing clotting and/or become infected, resulting in additional hospitalization. Using existing veins/arteries is limiting as the supply is not endless, as many as 40% of bypass patients are unable to choose this option due to disease or previous use.

Tissue engineering  – a process that makes replacement blood vessels, in vitro, a reality – allows for a long-term solution for bypass patients. A patient’s cells are grown on a 3D scaffold, which could be natural or a manufactured material, in an environment that is similar to the body. The resulting tissue is then implanted in the patient. With tissue engineered parts, you are not “borrowing” from other areas of your body reducing the concern about availability and because the concern for rejection is obsolete, because the patient’s body recognizes the cells as its own.

To be successful, tissue engineered implants must be both biologically and mechanically similar to native tissue.  This means that the scaffold material and the end products are tested and characterized using tension, compression, and other forces to make sure that they can endure the physical strains of implantation.  Research has also shown that growing tissues under these same mechanical forces (exercising the tissue) results in a tissue similar to native tissue.

In addition to heart disease treatment, tissue engineering has the ability to change modern medicine in many different areas.  Pediatrics is a special case.  Current mechanical medical devices are able to “cure” pediatric disease and defects; however because the patients are babies and their bodies are growing quickly, the surgery must be repeated many times to correct the size of the device.  Tissue engineering offers a solution that can grow with the patient and minimize the number of invasive surgeries necessary. Read more

Google for Test Results

There are many situations where we need to analyze test results, not just from one sample file, but results that are spread across different sample files that were tested at different times with slight differences in setup or calculations. Are you ever in a situation where you would like to have all the relevant data together without spending a lot of time going through multiple files and copy-pasting the results? The answer to this lies in storing your results in a database. Unlike a file-based system, database storage is optimized for search and retrieval of information. It allows you to quickly narrow down to the right data set within seconds and it saves your search criteria for future use. This decreases the amount of time lab operators spend on moving and organizing data, while increasing the productivity and throughput of the lab.

Earlier this month, Parasar Kodati, Software Product Manager, hosted a live database management webinar. If you missed the opportunity to see it live, you can now take advantage of watching the webinar at your convenience.

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