Technical Transactions. Vol. 12

Technical Transactions. Vol. 12

Type: Collection of magazine numbers
Release date

Collection items (20)


Effects of aortic valve diseases on pressure profiles in selected locations of the human arterial system

Majka, Marcin, Gadda, Giacomo, Taibi, Angelo, Zieliński, Piotr
Article
2017
Aortic valve diseases such as aortic stenosis and aortic regurgitation, are the most frequent valvular heart diseases. The lesions in the valves affect circulation in the whole arterial system. We study the effects with the use of a 1-D model in which an arterial segment transmits a single mode of pulse waves. The appropriate reflection coefficient and the form of the stroke pressure are devised to simulate the function of the healthy and morbid aortic valve. The time dependence of the arterial pressure is predicted at the most important locations of the arterial tree. A remarkable result is that little variations of the reflection coefficient of the vale due to the modelled diseases cause significant changes of the pressure profiles, especially at the ascending aorta, the left brachial artery and in the anterior communicating artery.

Austenitic steel surface integrity after EDM in different dielectric liquids

Żyra, Agnieszka, Bogucki, Rafał, Skoczypiec, Sebastian
Article
2017
Electrodischarge machining (EDM) can be used as an alternative machining method compared to conventional ones, especially while very good surface integrity and high machining accuracy during machining of difficult-to-cut materials is needed. In EDM, the dielectric liquid has a crucial influence on the technological material surface integrity since it ensures the occurrence of controlled electrical discharges between the tool and the workpiece, cooling and solidification of gaseous EDM debris, removing erosion products and also dispersing heat generated during the process. In the paper, the influence of a carbonbased and a water-based dielectric liquid on the selected structural and morphological characteristics of 304 stainless steel after EDM sinking was investigated. The surface roughness, micro hardness and quality as well as the chemical changes after the corrosion test of machined surfaces were analysed.

The use of machine vision to control the basic functions of a CNC machine tool using gestures

Miądlicki, Karol, Saków, Mateusz
Article
2017
This paper presents a concept of a vision system which can simplify the way in which some basic functions of CNC machines can be controlled. The proposed system enables the operator to control a machine tool using gestures. The developed solution is based on Microsoft Kinect for a Windows v2 sensor with a time-offlight camera. A gesture recognition module was implemented in the VC 760 milling machine with an open control system (O.C.E.A.N.). To conduct tests of the proposed interface, a set of gestures used to control a CNC machine was developed. Furthermore, the concept, the structure of the system and the test results are discussed. In summary, the advantages and potential problems of the proposed control system and plans for future development are discussed.

The cost of risk evaluation in intermodal transport – variant analysis

Lorenc, Augustyn, Kuźnar, Małgorzata
Article
2017
In the article, the impact of monitoring systems on the possibility of lowering costs and improving the flow of information in the transport chain has been analysed. For the analysed transport chain, tree variants have been taken into consideration: variant I – without using systems for monitoring location, variant II – container transportation with using systems for monitoring location, variant III – container transportation with using location monitoring and cargo parameters. The conducted tests made it possible to confirm the benefits of implementing this type of system, especially for high-value goods. In the article, a simulation for 50,000 cases of container transportation was done. The simulation and cost analysis has shown that it is possible to reduce the cost of risk significantly.

The proposed design of a refrigeration system with an energy-efficient chiller with adjustable capacity for a fruit storage chamber

Sikorska-Bączek, Renata
Article
2017
This article presents the design of a refrigeration system with an energy-efficient chiller for a fruit storage chamber. This is a direct evaporating refrigeration system with an energy-efficient, multi-compressor chiller with an air-cooled condenser. Refrigeration systems with multi-compressor chillers, adjustable efficiency and system components that enable efficient and stable operation will reduce electricity consumption and increase reliability of the system during operation.

The usefulness of cluster analysis in the analysis of data obtained in the monitoring of the water environment

Kubala, Marek
Article
2017
Data obtained through the monitoring of the water environment often includes a number of indicators, and is frequently collected from a large area or over a long period of time. Analysis of such data can be problematic. The division of elements which have a certain degree of similarity into subgroups may facilitate data analysis and provide indications as to the direction of the analysis. One tool for the separation of such groups of similar elements is cluster analysis. This paper describes the two most commonly used cluster analysis algorithms and summarises the results of several applications of cluster analysis in water monitoring.

Advantages and disadvantages of the solar drying of sewage sludge in Poland

Bożym, Marta, Bok, Agnieszka
Article
2017
Solar drying has become a popular method of sewage sludge processing in Poland over recent years. This is due to the possibility of using a renewable source of energy and the fact that solar dried sludges can be used for energy purposes. Over the last ten years in Poland, almost thirty solar or hybrid greenhouses of sewage sludge have been built. The aim of this work is to present the advantages and disadvantages of the solar drying method of processing sewage sludge. The advantage of using solar greenhouses are the use of renewable energy sources for sludge drying, their low operational costs, the reduced sludge volume, their preparation for thermal utylisation, simple construction and easy operation. The disadvantages are that drying efficiency depends on climatic conditions and season, the need to use additional heat sources, the fact that facilities occupy a large area and the possibility of odors emission released during drying of the sludge.

Assessment of propagation of modelling un-certainty by the procedures for determining maximum dynamic errors

Tomczyk, Krzysztof, Sieja, Marek
Article
2017
The paper discusses the method for modelling linear analogue systems of the second order in the time domain. As a result of such modelling, the parameters of the model and the associated uncertainties are obtained. Procedures for determining the absolute error and the integral-square error are presented. These procedures make it possible to determine precisely such an input signal with one constraint that maximizes an error at the output of the system. Values of the parameters of an example model are determined and the propagation of the uncertainties of modelling results is assessed by the procedures for determining the maximum dynamic errors. The results of calculations presented in the paper were carried out in MathCad15.

Point cloud based viewshed generation in AutoCad Civil 3D

Orlof, Jerzy
Article
2017
We propose a new method for a point cloud based viewshed generation. We start with a brief summary of existing methods for viewshed generation and then present ours based on point clouds. The method is implemented in AutoCAD Civil 3D. Moreover, we present an idea of how to deal with huge point clouds using AutoCAD Civil 3D and how to automatize this process.

Calibration of microsimulation models of advance detection and warning systems at signalized intersections

Wojtal, Remigiusz, Rilett, Laurence R.
Article
2017
This paper presents a calibration and validation procedure for microsimulation models, which used metrics (mean, variance, and mean absolute percentage error) with statistical tests (t-test, Shapiro-Wilk, KolmogorovSmirnov and Wilcoxon), to compare empirical and simulated data. A genetic algorithm was used to identify calibration parameters set. The paper justifies the approach using VISSIM microsimulations to analyze two safety countermeasures: Advance Detection System and Advance Warning System, which can be applied at signalized intersection. The end result was a calibrated and validated model, which could be used to compare different safety countermeasures at rural signalized intersections in the state of Nebraska (USA). The proposed approach could be utilized in similar studies.