There are a lot of hidden dangers in the world. Every day, we use or come in contact with a wide variety of materials. While most of what we eat or interact with is perfectly fine, there are times when we might encounter a product or even a place that might endanger our safety. There are some things we can look out for, but in most cases we’re make an implicit assumption that what we come into contact with is safe. Having this more relaxed attitude is possible because we have strong quality control standards, and a robust program of sophisticated scientific testing.
One method of advanced testing is SEM, or Scanning electron microscopy. This testing methodology is used to produce very high-resolution images of a surface that is being studied. While testing methods such as light microscopy rely on visible light, with SEM the magnification is at much greater levels, up to some 100,000X. The depth of field achieved by SEM can also be greater by a factor of 100. With this form of testing, you put a sample in the chamber and then SEM generates a beam of electrons. These electrons encounter the atoms in the sample and in turn produce key signals that will be analyzed.
Evaluating Concrete Cracks and Enhancing Safety
SEM played a critical role when concrete was originally developed, and then refined to produce the best possible product. Specifically, SEMs were utilized to study different hydration formulas and help determine the strength of the concrete.
This form of testing has also been used to study micro cracks in concrete. These appear in the initial concrete forms, and also when concrete becomes subject to stress that is load-induced. Based on SEM testing, a new procedure was developed that involved pouring a molten metal alloy into cracks that were caused by load pressure.
Environmental Concerns at an American Landmark
The Golden Gate Bridge, which connects San Francisco and Marin County to the north, is one of the most well-known landmarks in America. Built in the 1930s, it features beautiful towers, sweeping cables and an iconic color of paint. The trademark orange vermilion color was created by first applying a primer layer of red lead paint, then adding a top coat that also contained lead.
Later, in a project that spanned some 30 years, the lead-based paint was removed and then replaced with a zinc-based coating. Unfortunately, testing showed that the soil under the Golden Gate had a high lead content. This could have been from gasoline that was leaded, the lead paint or from some other cause. Scientists conducted tests using SEM and EDS (energy dispersive x-ray spectrometer). Results showed that the specks discovered in the soil under the bridge were from the original paint, and were the source of the high soil lead content.
Creating New Edible Probiotic Delivery Methods
Often, probiotic delivery systems are based on dairy. During the production process, these probiotics lose viability because of the mechanical stress, heat and other factors. Scientific researchers performed tests, looking for a new way to give consumers healthy probiotics in baked products that would be readily available in stores.
As part of this process, they were able to develop probiotic film that was edible and could be applied to the baked goods. SEM testing was then used to determine whether the heat from baking would destroy the presence of the probiotics. By adding whey proteins into the mix, the correct level of probiotic was maintained.
