In this last article on low-cost air quality sensors, we look more closely at particulate matter (PM) sensors, also called “dust” or “smoke” sensors. by Jim Rowe
Hotel History: The Palace Hotel (1909), San Francisco, Ca (556 rooms): San Francisco and the Palace Hotel have shared a common heritage for more than 140 years. Inspired by a visionary developer, William Chapman Ralston, the Palace Hotel was known as the “Grande Dame of the West”, a hotel of timeless elegance and unprecedented opulence. It was designed by architect John P. Gaynor as the largest, costliest and most luxurious hotel in the world. To finance its $5 million cost, Ralston exhausted his Bank of California which collapsed in late August 1875. Soon thereafter, Ralston’s body was found floating in San Francisco Bay. Nevertheless, the Palace Hotel opened two months later on October, 1875. Nevada’s U.S. Senator William Sharon, one of Ralston’s partners, who was known as the “King of the Comstocks” ended up in control of the hotel when he paid off the Bank and Ralston’s debts with pennies on the dollar.
Many new air quality sensor modules have been appearing on the market, some being surprisingly inexpensive. Here’s a quick rundown on what they do and how they work. Sensor types covered in this article include MOS, NDIR, PAS and PMC. by Jim Rowe
Bridges have been bringing people together to share experiences for centuries: The London Bridge that we all sang about "falling down" as children; the Brooklyn Bridge over which P.T. Barnum led 21 elephants; and the Ponte Vecchio Bridge in Florence the only Florentine bridge to survive World War II.