István Budai

Comparison of Different Theoretical Models to Experimental Data on Viscosity of Binary Liquid Alloys

Six different theoretical equations are compared in the present paper with experimental data, measured for 28 binary liquid metallic systems. General conclusions are drawn on the ability of the different theoretical models to describe the concentration and temperature dependence of the viscosity of liquid alloys. A new equation is derived, being able to predict the viscosity in multicomponents alloy even if the viscosities of the pure components are not known.

Analysis of literature models on viscosity of binary liquid metallic alloys on the example of the Cu-Ag system

The aim of this paper is to review all the existing literature models on the concentration dependence of the viscosity of binary liquid alloys and to check them against the measured viscosity values in the binary liquid Cu-Ag system at 1373K.

Business process development with the application of simulation technique

The object of our work to increase production efficiency with the use of cost-efficient development tools at a Hungarian small enterprise. We apply data gathering techniques besides process modelling and diagnostic methods to reduce the total process time of the assembly process so as to induce cost reduction in the production. In this respect we investigate and rank root causes of wastes by cost-effective process development tools, like timebased FMEA (failure mode and effects analysis) as well as the 5 whys method. With the use of Monte-Carlo simulation companies can evaluate the change in the process, therefore, they can decide whether they want to carry out corrective measures or not. The accomplished changes can generate increasing competitive edge in the long run.

Role of Lean and Agile Supply Chain Models for Pellet Fuel Technologies

Business organisations constantly strive to improve their processes, both internal and external. Within the supply chain of a product, different strategies can be applied. This paper aims to answer the basic questions like what is the core of lean and agile SCM strategies, what are the differences of the two models, and how can they be combined. This paper examines further, which of these SCM models and what elements of them can be applied for wood pellet supply chains, also examining the possibility of their combination. The result of these examinations is, that even though fuel pellets can be considered as simple commodity and not a very innovative product, diversity in input characteristics, optimization of fuel pellet technology process variables and changes in output market qualities and quantities need sometimes agile, flexible answer from pellet fuel SCM. The basically lean character of pellet fuel technologies and SCM can further enhanced by implementing agile SCM model elements, as is the increased integration of suppliers into the supply chain.

Model calculations on the use of mobile and stationary units for wood pellet production

This paper presents the model calculations made for supporting the decision making of different technology alternatives. Base cases were A) use of a mobile pelletizer and B) using pellet factories at fixed locations for the production of a new product, sheep wool pellets. Calculations were made for three alternatives for each base case. The results of the model were used to examine the energy, time and cost criteria of the alternatives. Based on the given preliminaries, results of the model calculations supported the recommendation to choose case B) for further technology management and supply chain management decisions.

Autóipari termelő vállalat gyártási folyamatának optimalizálása lean eszközökkel Optimization of automotive industry's manufacturing process with lean tools

Lean plays i mportant role in industrial environment. Auto motive industries use lean tools in order to reduce cost and i mprove productivity. To achieve the companys objec tives and so lve the detected problems I also used lean tools. By using lean tools we want to decrease total process cost ( TPC). In order to achieve this target, the three-shift production has to reduce in two-shift production, which result dec rease in the human resource costs and production costs. In order to reduce shifts we have to increase overall equipment efficiency (OEE) and eliminate minimum 50% of wastes by implementing 5s methodology, using Poka-yoke and scheduled maintenance.

STRUCTURAL ANALYSIS AND ITS STATISTICAL EVALUATION OF A CLOSED-CELL METAL FOAM

The development of an efficient procedure for 3d modeling and finite element simulation of metal foams is one of the greatest challenges for engineer researchers nowadays. Creating 3d CAD model is alone a demanding engineering task due to its extremely complex geometry, and the proper finite element analysis process is still in the center of the research. The increasingly widespread application of the metal foams, e.g. in vehicle and medical industry, requires this knowledge in the design phase. A closed-cell metal foam is studied using different analyzing methods where the aim is to collect information about the composition and geometry (structure) that is satisfactory for the later research. Using statistical methods microscopic, X-ray and surface analyzing studies on the specimens produced according to the concerning standard are evaluated. The main goal of this part of the project is to obtain structural information and to determine the homogeneity or the in-homogeneity property of the metal foam spec...

Intermetallic phase stabilized Al/Pb metallic emulsion

Abstract In the present paper the stabilization of Al–Pb metallic emulsion was studied. The pure liquid Pb is dispersed in liquid Al-rich Al–Sr alloy which contains dispersed Al4Sr precipitates. The Sr is dissolved in the Al-rich liquid and it is redistributed into the Pb phase. By the emulsification method the new Pb3Sr phase droplets are homogeneously dispersed in the Al-rich matrix. The Al–Pb metallic emulsion is cooled spontaneously.