Petri Networks in the Planning of Discrete Manufacturing Processes

This chapter puts forward characteristics of selected issues of manufacturing processes planning using the Petri networks technique. It includes references to the extensive literature concerning the use of Petri networks in computer aided planning of discrete production processes. Diversity of these problems is high as it refers both to the methods of modeling and simulation of the course of manufacturing processes, the issue of optimizing these processes and production systems, representation of knowledge on production parts of equipment and integration of planning and production activities in general. The work puts forward example use of a temporary, priority Petri network for modeling and optimizing production systems and manufacturing operations as well as an example of fuzzy interference using the Petri network mechanism

Determining the maximum loadability for the plastic cycloidal gears

The article presents the analysis of stresses and displacements which occur in the cycloidal gears working in the gerotor machine. The authors considered a possibility of using plastic (polyoxymethylene POM) for manufacturing the gears. The analysis has been conducted by means of the finite element method. Determining the maximum value of pressure which can be applied in the gerotor machine featuring plastic gears is the result of the analysis

Determining Rheological Parameters of Generalized Yield-Power-Law Fluid Model

The principles of determining rheological parameters of drilling muds described by a generalized yield-power-law are presented in the paper. Functions between tangent stresses and shear rate are given. The conditions of laboratory measurements of rheological parameters of generalized yield-power-law fluids are described and necessary mathematical relations for rheological model parameters given. With the block diagrams, the methodics of numerical solution of these relations has been presented. Rheological parameters of an exemplary drilling mud have been calculated with the use of this numerical program

OPTIMAL FEED RATE CONTROL STRATEGIES FOR FRICTION DRILLING

The presented paper contains the results of research aimed at developing optimal strategies for controlling the feed rate in the friction drilling process. In particular, the use of linear variable feed rate for individual drilling stages and adaptive feed rate control have been tested. The experiments were carried out with the use of a CNC machine tool equipped with an axial force and torque sensor. Correlation between thrust force and torque was shown, respectively, in relation to the feed drive load and the drive of machine tool spindle. Based on this, a feed rate sensorless control strategy was created to protect against excessive and long-term overload both of the tool and the drives. The following assessment criteria were considered: drilling cycle time, maximum values of thrust and torque, maximum values of feed drive load and drive of machine tool spindle, maximum power and energy effect in the form of work necessary to perform during the drilling process and forming the hole flange. The obtained test results, made for low-carbon steel with a tungsten carbide tool, indicate the advantage of the approach based on the linear variable feed rate and adaptive control over the traditional drilling process based on the step change of the feed rate, according to the recommendations given by the tool manufacturers

Algorithms of Optimum Slurry Selection for Soil and Rock Sealing Operations

Technical problems, usually caused by complex geological and hydrogeological conditions, are often encountered in mining, drilling and geoengineering operations, as well as in hydrotechnical and underground construction.Natural hazards in the above engineering operations are frequently liquidated by reinforcement and sealing of the ground with the use of injection methods with pre-selected sealing slurries.The authors present methods for slurry technological parameters normalization, depending on the scope and target of sealing operations, and algorithm of slurry selection of soil and rock sealing

An idea of the electronic control system for the multifunctional hydraulic machine

The paper presents an electronic control system for application in mobile hydraulic systems. Key components of the system and its advantages have been discussed. A multifunctional hydraulic machine, its design and operation principle have been presented. The concept of control work machine with the electronic control system has been developed. The benefits of integration of these systems have been highlighte

Background Traffic Simulator - The Tool for WLAN Background Traffic Generation in ns-3 Environment

In the paper, the BTS (Background Traffic Simulator) tool is proposed to capture network traffic and then reproduce it in a simulations using the ns-3 simulator extension module. This new method of generating background traffic allows for repetitive testing of simulation scenarios under real network conditions. The authors described the differences between the previously available methods and the proposed solution. The operation of all the most important elements of the proposed tool has been described. The influence of the generated background traffic on the simulation scenario was presented as well as the results of the operation

NEW POLIMER SEALING FLUID STOPS MUD LOSS

U radu je prikazana receptura tamponažnog fluida pripremljenog na bazi vodene otopine produkata ak-rilne kiseline pod nazivom Solakryl M. Dal je prikaz rezultata laboratorijskih ispitivanja tehnoloških svojstava modifikacija predloženog tamponažnog fluida s dodatkom mineralnih punila. Predstavljena je metoda izvođenja operacije tamponiranja propusne zone naslaga za slučaj primjene opisanog fluida. Komentirani su efekti primjene predloženog tamponažnog fluida i metode njegovog utiskivanja u izuzetno složenim uvjetima izrade bušotina za zamrzavanje.This paper deals with a composition of sealing fluid, prepared from acrylic acid salt water solution Solakryl M. Laboratory test results of technological properties of its modifications with mineral agents are shown. A new method of sealing mud loss operations with given sealing liquid is discussed along with comments on effects of its use for stopping mud loss in case of freeze-well drilling is described

Numerical analysis of corrugated steel plate bridge with reinforced concrete relieving slab

The paper presents a numerical analysis of corrugated steel plate (CSP) bridge with reinforced concrete (RC) relieving slab under static loads. Calculations were made based on the finite element method using Abaqus software. Two computation models were used; in the first one, RC slab was used, and the other was without it. The effect of RC slab to deformations of CSP shell was determined. Comparing the computational results from two numerical models, it can be concluded that when the relieving slab is applied, substantial reductions in displacements, stresses, bending mo­ments and axial thrusts are achieved. Relative reductions of displacements were in the range of 53–66%, and stresses of 73–82%. Maximum displacements and bending moments were obtained at the shell crown, and maximum stresses and axial thrusts at the quarter points. The calculation results were also compared to the values from experimental tests. The course of computed displacements and stresses is similar to those obtained from experimental tests, although the absolute values were generally higher than the measured ones. Results of numerical analyses can be useful for bridge engineering, with particular regard to bridges and culverts made from corrugated steel plates for the range of necessity of using additional relieving elements. First published online: 15 Jan 201

Testing of a Stand for Analysis of Drilling Mud Friction Factor

A concept and realization of a universal laboratory stand for analyzing hydromechanical effects accompanying the drilling mud flow are presented in the paper. Requirements for basic technical subassemblies of the stand are defined. The principles of a flow meter, pressure converters and digital data readers are presented. Then a scheme of a laboratory stand, its principle and procedure are discussed. The process of stand testing through an empirical determination of the Faning friction factor for Newtonian fluids is presented and compared with literature data