Below are excerpts from The 2013 DuPont Challenge grand prize essays.Jacob Yoshitake, Junior Division Grand Prize Winner
Excellent, Efficient, and Economical Solar Tracking (excerpt)
Free, limitless, clean solar energy showers the earth daily. However, most solar panels only harness a fraction of this energy. It is well known that solar tracking, pointing a solar panel perpendicular to the sun's rays, improves efficiency. Most solar panel arrays that are seen on buildings are static (non-moving). This is because existing tracking systems are extremely expensive and complex. Although there is unlimited energy, a cost-effective solar is needed to harness that energy to its fullest.
…Solar trackers are very expensive because of the materials that are used to make them. Existing solar trackers are fixed to the ground. Because the tracker is not mounted on the panel, the tracker needs to have intricate computer chips, expensive microprocessors, and complicated algorithms to determine the location of the sun and aim the panel at it. My tracker has an innovative shadow box sun sensor that is attached to the solar panel. A photodiode, a small electric eye, is in the far back corner of the box. A slit in the box was cut so that light shines on the photodiode only when the box is not perpendicular to the light source. When the photodiode sees the light, it will send an electrical signal to the system to make the motor move. As soon as the solar panel and the shadow box are perpendicular to the sun, a shadow falls over the photodiode and the panel ceases movement.
…Protecting the environment is crucial for this generation and future generations. My solar tracker may make green energy more popular and benefit the environment. Using half the roof space or doubling the efficiency of a static solar panel, this inexpensive solar tracker opens a new market for solar installations on buildings with minimal roof space (e.g., large apartment buildings and high-rise offices). Reducing costs and roof space requirements, the simple, efficient, and inexpensive solar tracker that I developed should encourage more people to switch to solar power. Such a change would make the environment cleaner, healthier, and more enjoyable for generations to come.
Flavonoids: The Avengers of Rice Bacterial Blight (excerpt)
A fragrant aroma climbs into my nose, taking root and arousing my other senses. While my eyes greedily absorb the light reflected off the pure grains of white, my tongue explores the fluffy softness of the starchy clouds. Finally, I crush the grains, releasing the natural sweetness husked within. Rice. This staple crop is of primary importance to the world, with its annual 466.8 million tons of grain accounting for over twenty percent of the world's caloric intake (Kubo and Purevdorj 2004). Yet, an evil seeks to destroy this treasure. Invisible, pervasive, and deadly, it leaves calling cards in the form of pale yellow lesions on rice leaves (Gnanamanickam 1999). Within weeks, its victims, unable to photosynthesize, perish. It spreads through fields faster than flames, reaping without mercy. A killer of rice, its name is Xanthomonas oryzae pv. oryzae (Xoo).
…Oryza longistaminata has been discovered to be resistant towards Xoo infection (Ronald and Beutler 2011). Its particularly robust immune system is able to crush invaders quickly and efficiently. Investigation into its properties revealed that the rice strain contains Xa21, a unique protein that detects Ax21 molecules released by Xoo. Upon detecting Ax21, Xa21 activates a more thorough immune response, allowing the strain to ward off invading Xoo. However, though initially promising, Xa21 ultimately was not the secret weapon that was needed, as there were many challenges related to transferring the Xa21 gene to other rice strains (Jeung 2006). Instead, it is Xoo's own protein, Ax21, that has proven to be the pathogen's ultimate weakness.
…Though the journey took years of wandering through the realms of microbiology and plant pathology, the knights finally found their treasure in the form of flavonoids, a class of plant-derived metabolites naturally found in many fruits, herbs, and vegetables… Though flavonoids have not yet been commercially developed as a treatment for Xoo, the potential they hold is great. In helping rice plants defeat the feared invader Xoo, flavonoids may be able to save millions of tons of rice, allowing more of these pure grains to reach the mouths of billions throughout our world.