And this cause was emphasized when Samuel, the Lord’s prophet, anointed David to be a future king of Israel. Young David, shepherd boy of Israel, had a cause. They need a purpose for living, a reason to be-they need a cause. They attach themselves to this or that organization or group because they wish to make the world a better place. Many young people of today are great joiners. When accused of pride, the future king of Israel asked his oldest brother, “Is there not a cause?” ( 1 Samuel 17:29). David’s actions showed that his answer to such a question would have been a hearty “I am!” Arriving at the battlefront at a time when the haughty giant Goliath had openly challenged Israel to send a man to fight him, David boldly volunteered to accept Goliath’s challenge. Follow LiveScience on Twitter, Facebook and Google+. In addition to their dragon-fish studies, the team is analyzing the structures of other armored fish, including the three-spined stickleback and armored catfish, in order to compare different natural systems and ultimately pick and choose sets of qualities most suitable for human protection.įollow Laura Poppick on Twitter. "After we solve that, then we can start talking about durability, and the durability of different systems is going to be driven by the materials that you use in them." "Our aim is enabling user mobility," Varshney said. For example, scaly armor made from heat-resistant materials, such as ceramic, could provide thermal protection for firefighters, or lighter-weight material could be configured to create flexible neck guards for football players, Varshney said. Army, so they expect their results to have some military applications but also hope to expand to other realms of human protection as well. The team will use their results to test the structural limits of different combinations of materials and designs, with potentially wide-ranging applications. "Instead of cracking outward, it actually goes inward, dissipating energy to stop the penetration without sacrificing the structural integrity of the entire system." "What nature does, in many cases, is it suppresses radial cracking in ceramics, and instead, it basically cracks in a circle right around the impact," Ortiz said during the lecture. The physical composition of the ceramic scale also contributes to its durability, the team found: The ceramic endures cracks in such a way that the energy dissipates inward, rather than radiating outward as other brittle materials do. Such variations can help inform how armor can be tailored to the human body to protect regions of high mobility, such as elbows, versus those of lower mobility, such as forearms. The exact arrangement of the scales varies across the body depending on the range of motion required in different regions, Ortiz said. In their imaging analyses, the team has found that dragon fish scales have smooth ridges and corresponding indentations that allow neighboring scales to fit snuggly together like puzzle pieces. The team then examines the scales using microscopic imaging and 3D scanning, and ultimately creates 3D-printed models - blown up more than 10 times the natural scale size - to conduct mechanical tests that would otherwise be extremely difficult to perform on the real, and much smaller, scales. 3D-printed prototypes of Polypterus senegalus scales.
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