Sufficiently Fat Polyhedra are Not 2-Castable

نویسندگان

  • Alexander Golynski
  • David Bremner
چکیده

In this note we consider the problem of manufacturing a convex polyhedral object via casting. We consider a generalization of the sand casting process where the object is manufactured by gluing together two identical faces of parts cast with a single piece mold. In this model we show that the class of convex polyhedra which can be enclosed between two concentric spheres with the ratio of their radii less than 1.07 cannot be manufactured using only two cast parts.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

4.3 a Data Structuring Approach

25] Seidel, R., Small-dimensional linear programming and convex hulls made easy. range searching and new zone theorems. A linear time algorithm for determining the separation of convex polyhedra. Two dimensional computation of the three dimensional reachable region for a welding head. 29 list some open problems related to this paper, and then list a few others in cast design that deserve attent...

متن کامل

No-net Polyhedra

1. Introduction. It is often said that when the conditions are right, discoveries are made by different people at the same time. The discovery of the non-Euclidean geometry, and the invention of calculus are the most frequently mentioned examples. Here is another example (with an incomparably less significant subject) which I noticed recently. My note [4] described a starshaped polyhedron which...

متن کامل

Modelling Decision Problems Via Birkhoff Polyhedra

A compact formulation of the set of tours neither in a graph nor its complement is presented and illustrates a general methodology proposed for constructing polyhedral models of decision problems based upon permutations, projection and lifting techniques. Directed Hamilton tours on n vertex graphs are interpreted as (n-1)- permutations. Sets of extrema of Birkhoff polyhedra are mapped to tours ...

متن کامل

Preparation and properties of low cement castable sintered at different temperatures#

The low cement high alumina castable (LCC) studied in this paper was synthesised, cured and then treated at different sintering temperatures. Since any inhomogeneity introduced during the castable preparation can remain inside the material degrading its properties and therefore the quality during service life, particular attention was given to the processing procedure in order to produce the ma...

متن کامل

Effect of Combining Hydraulic and Phosphate Bonds on Alumina-Spinel Low Cement Castables

A basic alumina-spinel low cement castable (LCC) composed of sintered bauxite, reactive alumina, calcined alumina, calcined magnesia, microsilica, and high alumina refractory cement was prepared (castable A) to which 5% sodium hexa-meta phosphate was later added (castable B) to prepare samples for heat treatment at 110ºC, 900ºC, and 1400ºC. Bulk Density (BD), Apparent Porosity (AP), and Cold Cr...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2003