Good Proprieties Research Articles

Thermal Chamber for Adhesives Creep Multi-Station Testing Machine

Adhesives have been used in a wide range of industries, due to their good proprieties when compared with traditional joining methods. Therefore, manufacturers and researchers have been making an effort to study these materials and their characteristics.The main goal of the Advance Joining Processes Unit (AJPU) of FEUP/INEGI is to study and evaluate different types of adhesives under different conditions. One equipment available at the AJPU is a creep testing machine with three independent working stations. As the creep tests must be performed under controlled temperature, the implementation of a thermal chamber was required.This paper describes the design of a thermal chamber for the existing creep testing machine. The chamber needs to be capable of operating between -100 and 200 ºC and have a low temperature gradient. The first step was to design a heat insulator for each upper rod of the creep testing machine, in order to limit the temperature at the load cells to service values.Subsequently, the concept of the chamber was developed. The design decisions with influence on the thermal efficiency of the chamber were supported analytically. The structure, insulation, control and automation projects of the chamber are presented in detail.

Influence of cutting parameters on surface hardness in milling of AL6061T6

Milling is an important industrial common machining operation used to produce complex surfaces. Surface quality in milling operation is influenced by various factors such as cutting speed, cutting feed, depth of cut and chemical composition of the material. Surface quality is defined by roughness, residual stress and microhardness and is important in determining corrosion resistance and in fatigue crack initiation. The aim of the present paper is to analyse the influence of above-mentioned cutting parameters (cutting feed, cutting speed, depth of cut) on surface microhardness. Tests were conducted using a Coro mill 490 with a single insert that was indexed for every experiment, thus eliminating the influence of tool wear. Al 6061-T6, a material widely utilised in aircraft, defence, automobiles, and marine areas due to its good proprieties (good strength and lightweight) was used. Microhardness was measured on workpiece surface but also in the cross section of the workpiece, up to a depth of 1mm, in order to observe material state in subsurface layer. It was observed from the results that an increase of cutting speed have led to an increase of microhardness while a higher value for depth of cut has led to a lower value of microhardness. Feed rate has generated similar results with the depth of cut.

Superlogic manifolds and geometric approach to quantum logic

The main purpose of this paper is to present a new approach to logic or what we will call superlogic. This approach constitutes a new way of looking at the connection between quantum mechanics and logic. It is a geometrization of the quantum logic. Note that this superlogic is not distributive reflecting a good propriety to describe quantum mechanics, non-commutative spaces and contains a nilpotent element.

Influences of Collared Ribs and Core-Holes on the Static Stiffness of Cylindrical Column : Study on the C.A.D for Machine Tool Structures, Part 1

In the Computer Aided Design for a machine tool structure being developed, there are two important problems to be solved to compute the overall stiffness of a machine tool. One is the limitation of the core size of computer, which affects largely the computing accuracy. Another is how a machine tool structure is replaced by a suitable model available to the computation with good propriety. To make some countermeasures for these problems, one trial of CAD was carried out here with the cylindrical column having collared ribs and core-holes. From the results, it can be concluded that the cylindrical column in closed cross-section is well replaced by an one-dimensional beam-like element notwithstanding the existence of collared ribs and core-holes. This means that there may be some possibility of a new CAD technique to solve the present problems. In addition to this investigation, the effects of collared ribs and the influences of core-holes on the static stiffness of cylindrical column have been also described here.