聚乳酸/天然纖維複合材料之研究-探討加入玉米葉纖維對機械性質之影響
本研究以玉米葉纖維做為聚乳酸纖維的補強材料,並以加入的玉米葉纖維長度為操縱變因,探討其對聚乳酸/玉米葉纖維複合材料機械性質的影響。實驗設計以純聚乳酸為對照組,以加入1mm, 2mm, 5mm, 13mm玉米葉纖維的聚乳酸複合材料為實驗組。本研究以拉伸強度和耐衝擊值來判斷機械性質的強度。 實驗數據顯示,實驗組的拉伸強度與對照組差距不大,但在耐衝擊值卻比對照組高出許多。除此之外,拉伸強度和耐衝擊值都顯示加入2mm玉米葉纖維在實驗組擁有最佳的數值。另外,加入越長的玉米葉纖維反而不會擁有較佳的機械性質。未來期待聚乳酸複合材料能夠應用在更廣的層面。
The Effect of Hands Free - Cell Phone Conversation on Visual Fields
It is a known fact that using a cell phone while driving can lead to reckless driving. According to research done by the World Health Organisation (2011) thousands of car accidents occur worldwide, each day, due to cell phone use whilst driving. Many of these car accidents result in serious injury or death of drivers, passengers or pedestrians. According to the Automobile Association (2012), cell phones are the number one cause of traffic accidents in South Africa. The high rate of car accidents due to cell phone use has led to legislation being passed, in most countries, banning hand-held cell phone use while driving. Hands-free phone equipment is not prohibited as it is widely regarded as a safe means of making and taking a phone call while behind the wheel. The purpose of this study was to show that the act of talking on a cell phone and not the method of talking (hand-held versus hands-free) increases accident probability. This study used a Friedman Visual field analyser which measures subject’s visual fields with and without engaging in hands-free cellular conversation. The results showed a significant constriction of the visual fields when subjects were conversing on a cell phone. These results were and can be explained by the fact that the test subject experiences cognitive distraction. Cognitive distraction occurs because the driver has to divide his/her attention between the cell phone conversation and the tasks relating to driving. These results have significant ramifications for road safety in a driving environment.