High technology of cutting disks rolling by spherical rollers

Cutting Disjoint Disks by Straight Lines

For k > 0 let f(k) denote the minimum integerf such that, for any family of k pairwise disjoint congruent disks in the plane, there is a direction t~ such that any line having direction ~ intersects at mostf of the disks. We determine the exact asymptotic behavior off(k) by proving that there are two positive constants dt, d 2 such that dlx/k.,/~gk~f(k)~d:,x/k~,/~gk. This result has been motiva...

High breeding performance of European Rollers Coracias

Cutting a Set of Disks by a Line with Leaving Many Intact Disks in Both Sides

Cut by a line the union of given disjoint disks in the plane so that both sides of the line contain many intact disks. At least how many intact disks can we leave in either side? It is proved that there is a family of infinitely many disjoint disks in the plane for which every line has a side that contains at most one intact disk. On the other hand, for any family of n disjoint disks, there is ...

High Speed Thin Metal Cutting using Fiber Laser Technology

There are several methods available for precision cutting of thin metals less than 0.06-inch thick used for these applications, which include materials such as stainless steel, titanium, nickel, and aluminum. The major options, lasers, electric discharge machining (EDM), water-jet, and chemical machining each have a role to play. However, precision fiber laser cutting technology is now emerging...

the effect of keeping reflective journals by language instructors on the process of reading comprehension among iranian high school students

خواندن ودرک مطلب از مهمترین مهارتها در یادگیری زبان خارجی محسوب می شود. این تحقیق تاثیر برگه های تامل برانگیز هدایت شده را در ارتقاع مهارت خواندن ودر ک مطلب در دانش اموزان دبیرستانی ایرانی بررسی می نماید. ازمجموع ?2 دانش آموز سال چهارم دبیرستان شهید رجایی شهرستان اسلامشهر¸ پس از اجرای آزمون استاندارد ((nelson 150a تعداد 39 دانش آموز که نمرات آنها یک سطح انحراف معیار بالاتر یا پایین تر ازمعدل قر...