Recent content by Trainee Engineering

I see. correct, I got this idea about UVA/UVB measurement because of my recent lab test suggesting I got Vit D deficiency. I was prepared to schedule a regular visit to the beach to start sunbathing (a bit overkill perhaps), but then, it struck me, I have a section of open space in my balcony...

thanks for the reply. can you explain more about this? how does one build this device? is this kind of device easy to build? thanks

thanks for the reply. but I read that polycarbonate distort and degrade under constant exposure to the elements. and sometimes, they also yellow overtime. is this true? thanks

Hi all, I'd like to know what is the most transparent material that;s waterproof, but not as brittle as glass. I want to put a "roofing" on a section in my balcony where I usually hang my clothes to dry and disinfect them under the sun, but I don't want to run all the way up everytime it rains...

trust me, that's what I thought at first. I have a fair complexion, with normal working lifestyle, full office clothing, 10 min walk outdoor under morning sun to MRT station at 7AM, arrived at office (indoor, no sunlight) before 8AM, 5 min walk outside under noon sun to lunch at 12PM and then...

I see. any guide on how often per week and how long per session staying under noon sun to achieve optimal vit D while avoiding skin cancer, melanoma, sunburn, etc? to maximize are of coverage, I'll be only wearing swimming trunks and cover my face with books cause pretty sure genital area and...

Hi all, I'd like to know if there's a reliable tool that can measure UVA and UVB concurrently at regular interval and record it. Or if can't record, then at least can be connected to a computer or network and will send the readings at regular interval. or perhaps anybody can point me to a...

hi jim, thanks for the reply. now this is very interesting. if you type "vitamin d sun" in google, all the result will say the opposite, it's UVB that you need to make vit D. like this one: http://www.nhs.uk/Livewell/Summerhealth/Pages/vitamin-D-sunlight.aspx which is NHS, UK government...

Hi all, which sun has highest concentration of UVB, but least concentration of UVA (skin cancer culprit). Right now, I'm in equator area (Singapore) with only 2 seasons (just in case if geography has any effect local sun's UV ray distribution). I've heard a lot of people saying that morning sun...

so, there's a UPS that can alternate between internal battery and external batteries? because I'm sure the normal batteries inside UPS will only last like 30 mins tops, I have an array of batteries that can last days, so I want to alternate between main power grid and said array of batteries...

I see. just to make sure, on that wikipedia article, what I'm looking for is the Online / Double Conversion UPS? and they can handle multiple power sources? so, I'll have an array of battery of 200 kWH for spare in case of outage. thanks

Hi, I'm looking for a device that is able to provide stable power and alternate between power sources. UPS, no matter how good they are, they usually still have several millisecond downtime during outage, switching from power grid to backup battery. I want a device that can accept power from...

I see. right now, I'm using http://keisan.casio.com/exec/system/1224682277 any other good source to get elevation / azimuth for the next 10 years, or maybe more? I definitely can tolerate 1 minute arc per decade miss. thanks

sorry, was occupied with something else. a follow up question, in this case, is it possible to determine sun's position (azimuth and elevation) on certain Earth GPS coordinate for like 10 years from now? so, azimuth and elevation of the sun on said GPS coordinate in 5-min interval starting from...

slow RPM. 1/6 deg per second is good enough. lower is also fine. basically, I just need to get ~4 degrees in 4 secs