It is a well known fact that crystals reflect X-rays when the incident X-ray beam makes a certain angle to a given set of atomic planes. In other words, this happens when the Bragg diffraction condition, which relates the incident angle, radiation wavelength and the interatomic spacing of the planes is satisfied. A not so trivial question to answer is what fraction of incident radiation is reflected for any given Bragg reflection and why. 

Career and Technical Education (CTE) programs are on the forefront of education reform across the region and nation, offering certification in a broad scope of paths in skilled trades such as construction, manufacturing, machining, and engineering.

What did the Scientists Discover?

Although singlet fission promises to boost device efficiencies, it is a complex process involving multiple steps. A loss incurred during any step would be detrimental to promised efficiency gains. Currently, few highly efficient singlet fission materials exist—a grand challenge is to develop structural rules that help guide the design and synthesis of new materials.

Before this is all possible, additively manufactured parts must be created with microstructures and compositions comparable to their traditionally manufactured counterparts in order to ensure the same required performance and safety integrity. One of the most-pressing problems that arises in the additive manufacturing process is the development of residual stresses.  These stresses that develop during rapid cooling essentially ‘spring-load’ a part before it is placed in service and can lead to premature failure.

Grace King, a rising Junior, majoring in Physics at Vassar College and studying Engineering at Dartmouth College, participated in the REU program at Cornell this summer, and her research project is quite timely, as CHESS and CESR are currently undergoing their biggest upgrade in decades.

However, the pervasive presence of granular materials masks how complicated it is to predict their mechanical response. Granular materials can behave as a solid foundation to a building, a flowing liquid down an incline, or as a gas when lifted into a storm. All these behaviors stem from how the contacts between grains evolve as load is applied.

CHESS is a circular particle accelerator that produces synchrotron radiation in the form of high-intensity, high-energy x-rays. These x-ray beams are instrumental for research in a wide variety of fields, including materials science, biology, and physics. The CHESS facility is connected with the Cornell Electron Storage Ring, which stores the beams of light accelerated by the synchrotron.

Ostwald ripening is a familiar effect – think of small water droplet condensing on a cold window pane. Sooner or later larger droplets form that will grow at the expanse of the smaller ones. Now imagine this random process proceeding in a highly organized way and with formation of symmetric patterns – such a behavior would seem rather unusual.

This type of repetitive use, or cyclic loading, leads to failure of everything from auto components to door hinges to plastic utensils. In the engineering world, understanding failure and predicting failure of parts and materials is important, yet a complete understanding of the processes which lead to failure remains incomplete. In addition to worrying about failure, engineers are also concerned with system efficiency. Many systems, such as automobile engines, run more efficiently at higher operating temperatures. Improving efficiency has enormous technical and economical relevance.