Oct 18, 2013

網路上計算一定天數後是幾月幾號的程式

對計算只能待一定天數的入境簽證有不少幫助
如:短期停留簽證,居留簽證
可以計算最晚要出境的日期
不過請留意是否從入境的第一天開始算 或是 從入境的第一天開始算
另外 還是要多方查證計算結果
畢竟逾期出境是要罰很多前前低
http://cgi.cs.duke.edu/~des/datecalc/datecalc.cgi

Oct 17, 2013

A miniature model of a gokart made of wood


A simple small kart model made of wood, and videos I made to illustrate the structure of a simple kart/go-kart. This is to show how a kart can lift one of the front or rear tires when it steers. This is because the plan of rotation of the front axial is not horizontal but tilted. During acceleration/deceleration the weight of the car can shift to back/front side making the outer front/inner rear tire lift. In the latter case (inner rear case) this helps the car to corner because a simple kart does not have differential on the rear axial or on the two rear tires. Normally when a kart corners the two rear tires will tend to rotate at different speed because the radius of their traces is different (the inner tire has a smaller radius and so smaller circumference.). This means the two rear tires have to rotate at different speeds, but they can not because they are on the same axial. This means during cornering one of the rear tires will always suffer friction, and thus slow down the car. Unless, one of the tire is lifted, not touching the ground! Hence the idea to make the structure so that one of the tires can be off the ground during cornering. See the cornering in action in the video below.
video
Two cases: 1) inner-rear lift, 2) outer-front lift.