Working Papers Many of the documents in this series are prepublication/preprint articles, which may subsequently appear (part or whole) in peer reviewed journals and books. In most cases they are draft documents, the purpose of which is to foster discussion and debate, prior to publication elsewhere, whilst ideas are still fresh. Citation notice Citation should conform to normal academic standa...

In many areas of Washington, it rains for a majority of the year. During rainy weather it becomes difficult to see street lanes and dividers, causing hazardous road conditions. The Piezoelectric Powered LED Street Reflector solves this problem. The PPL Street Reflector modifies a street reflector with LED lights. These lights help drivers clearly see where dividers and street lines are in non-i...

An overview of the rapid progress in the developments of the inorganic light emitting diode (LED) technology is presented. Innovative structures and designs of the device have led to dramatic improvements of the performance in LED technology, groundbreaking performance records are being reported constantly. This article summaries the recent progress of the high brightness LEDs, and describes th...

The performance of an LED-based, dual-beam, spectrophotometer is discussed. The difficulty with producing an LED based instrument in the past has been the limited choice of LEDs, particularly in the blue/green region. Recent advances in LED technology have made such a device possible. The instrument discussed uses commercially available LEDs and other off-the-shelve electronic components which ...