Monday, June 17, 2013

Monitor your vital signs through your smartphone

數年後, 很有可能你的智慧手機不再只是讀 email 或上網而已, 智慧手機可能會讓你更健康, 延續生命, 甚至警告你的器官 (例如心臟) 已經開始有一些不正常的跡象. 無線技術和微感應器的突飛猛進以及智慧手機的普及, 已經可以將你的大部分生命跡象和健康狀況 (血壓, 體溫,心跳, 心電圖, 血糖, BMI, 睡眠的品質, 孕婦的胎兒或子宮收縮監測等等 ) 全部即時地顯現在智慧手機上. 下面的17 分鐘 的精釆演講 (有中文翻譯字幕) by Dr. Eric Topol (一位知名心臟醫生) 闡述了無線電在醫療監測上的應用 (當然也代表這應用的無限商機和研究範圍). 這是2010 年的演講, 現在應已是更進步 (世界最大的手機晶片公司, Qualcomm, 已經開始投資手機在醫療上的應用)

Sunday, June 16, 2013

lush green but waterlogged strawberry



Rain, a lot of rain in the first two weeks of June, 6 inches of rain in the first 12 days of June which is 4.1 inches above normal. The waterlogged soil caused a lot of revenue loss for the local farmers of pick-your-own business, especially the strawberry. (NJ ranks #1 in terms of percentage for the farm revenue of pick-your-own agriculture)

Saturday, June 15, 2013

How much energy that we can enjoy from sun

How much energy that sun can give us as a free gift? I stumbled across a term, solar constant (=1361 Watt/m^2), which means the maximum energy density that sun can give us is 1361 Watt/m^2.  This term is associated with the energy that our rooftop solar panels can generate and probably any engineer that learned Planck's radiation law before should know how to calculate this 1361 W/m^2.   Since sun surface temperature can reach 5800K, it will generate 2.04e7 W/m^2/sr energy flux density.   The subtended angle from earth to sun is 0.53 deg.  Therefore, maximum power density that sun can give us is 2.04e7 *3.14 *sin(0.53/2)^2 = 1370 Watt/m^2 (God never allows sun to give us more energy density than this solar constant!)  However, at average 5500K sun surface temperature and consumer-grade silicon solar panel can absorb only 0.4-0.8 um wavelength, sun only emits 7.4e6 W/m^2/sr to silicon solar panels.    This implies that solar panel can best absorb 7.4e6 *3.14 *sin(0.53/2)^2 = 500 W/m^2.   At 20% efficiency, no wonder most of the rooftop solar panel can only generate 100 Watt/m^2 (i.e., 7% of solar constant).  That means for 10m^2 rooftop solar panel, it can only generate 1 kWh electricity per hour.

Solar-thermal renewable energy with 28,000 sun-equivalent brightness

Recent article in TIME has covered Ivanph, a solar-thermal project in California desert which can generate 14 億度/yr (臺灣的總電力裝置容量為每年2800億度, 核四每年240億度). It sprawls over 16 平方公里 with three gigantic solar towers, each with 150m height and 28,000 sun-equivalent brightness. In addition to 3 towers, it has 173,000 constantly adjustable mirrors, each with the size of garage door. Unlike solar-panels on the rooftop or wind-power farms, solar-thermal is a reliable renewable energy (if located in the year-round sun-drenched desert!). However, with price of solar-panels plummeting in recent years due to a glut of solar panels made in China, solar-thermal energy is still not as cost-effective as solar-panel energy, let alone the coal-fired power plant.

Thursday, June 13, 2013

office building with robots and nothing but robots?

Picture this, 10 years from now, the office building is staffed only with security guards and a whole bunch of mobile autonomous robots, each with 21" LCD display that constantly shows your face and what you are doing at home. Everyone can work at home since there is always one robot incarnation in the office that represents you. You can navigate this incarnated robot to any room in the office building to join the meeting, to make presentation or even just to have casual watercooler conversation when you are physically at home. This is actually available now but way too expensive ($25k/yr to rent a robot). It's likely that it will be very popular in the years to come.

Wednesday, June 12, 2013

Powerful boss may face comeuppance?

Powerful people are always undone by hubris? Probably it is true according to the study from the article in Economist. If you feel your boss is too arrogant or condescending, according to the study, he or she may face comeuppance. Former Intel's famous CEO, Andy Grove, had a sobering dictum: only the paranoid survive.

Sunday, June 9, 2013

Everyone wants cheap U.S. natural gas

Every country wants to have U.S. cheap shale natural gas which is only 30% of Japan's cost (1 million BTU on the following chart is equal to 293度電) because of its advanced fracking technology. Taiwan's natural gas comprises 11.6% of total energy consumption and imported 12.8M MT (million-tonne) natural gas last year. U.S. has already exported 33.5M MT/yr natural gas to Mexico and Canada through pipes. Now US is building facilities to liquefy natural gas to -162C for export purpose. Its total export capacity can reach 27.4M MT/yr in the next few years to Japan, U.K, Spain, Korea and India. Though A.I.T. has expressed willingness to sell Taiwan U.S. natural gas, it is hard for me to imagine Taiwan can get more than 5% of its 27.4M MT/yr.