Journal & Issues

Volume 31 (2023): Issue 52 (June 2023)

Volume 30 (2022): Issue 51 (November 2022)

Volume 30 (2022): Issue 50 (June 2022)

Volume 29 (2021): Issue 49 (September 2021)

Volume 29 (2021): Issue 48 (June 2021)

Volume 28 (2020): Issue 47 (September 2020)

Volume 28 (2020): Issue 46 (June 2020)

Volume 27 (2019): Issue 45 (September 2019)

Volume 27 (2019): Issue 44 (June 2019)

Volume 27 (2019): Issue s1 (December 2019)
Special Number

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Volume 26 (2018): Issue 42 (June 2018)

Volume 25 (2017): Issue 41 (September 2017)

Volume 25 (2017): Issue 40 (June 2017)

Volume 24 (2016): Issue 39 (December 2016)

Volume 24 (2016): Issue 38 (September 2016)

Volume 24 (2016): Issue 37 (June 2016)

Volume 23 (2015): Issue 36 (June 2015)

Volume 23 (2015): Issue s1 (August 2015)
Issue Title: Special number

Volume 22 (2014): Issue 341 (December 2014)
Special Issue

Volume 22 (2014): Issue 35 (December 2014)

Volume 22 (2014): Issue 34 (June 2014)

Volume 21 (2013): Issue Special-Issue (June 2013)

Volume 21 (2013): Issue 33 (December 2013)

Volume 20 (2012): Issue Special-Number (December 2012)
CO-MAT-TECH 2012

Volume 20 (2013): Issue 32 (January 2013)

Volume 19 (2011): Issue 31 (January 2011)

Volume 19 (2011): Issue 30 (January 2011)

Volume 18 (2010): Issue 29 (January 2010)

Volume 18 (2010): Issue 28 (January 2010)

Journal Details
Format
Journal
eISSN
1338-0532
ISSN
1336-1589
First Published
03 Mar 2011
Publication timeframe
2 times per year
Languages
English

Search

Volume 21 (2013): Issue Special-Issue (June 2013)

Journal Details
Format
Journal
eISSN
1338-0532
ISSN
1336-1589
First Published
03 Mar 2011
Publication timeframe
2 times per year
Languages
English

Search

0 Articles
Open Access

Contributions to Improve Online Learning Through Adaptive Hypermedia Techniques

Published Online: 08 Aug 2013
Page range: 1 - 6

Abstract

Abstract

The personalization of learning through the automatic adaptation of the educational process, especially for the contents, is regarded as an important and necessary step for the improvement of education in the future. It is believed that through individualization get improved efficiency, increased speed and quality of learning for students and by automating the process, improved efficiency, better resource utilization, scalability of the process learning. To achieve this goal we have developed different strategies. One of them are looking for Adaptive Hypermedia Systems adjust all contents in a atuomática to the characteristics of each user.

Keywords

  • Adaptive Hypermedia System
  • user modelling
  • educational dataminig
  • learning analytics
Open Access

Data Portability Among Providers o Platform as a Service

Published Online: 08 Aug 2013
Page range: 7 - 11

Abstract

Abstract

Platform as a service model has certain obstacles, including data lock-in. It is expensive and time-consuming to move data to the alternative providers. This paper presents data storage options in platform as a service offers and identifies the most common data portability problems between various commercial providers of platform as a service. There are differences among their storage models, data types, remote APIs for data manipulation and query languages. Representing data models of platform as a service and data mappings by means of ontology can provide a common layer to achieve data portability among different cloud providers.

Keywords

  • data portability
  • platform as a service
  • Cloud Computing
Open Access

Generalized Construction of Two-Dimensional Quasi Complete Complementary Codes

Published Online: 08 Aug 2013
Page range: 12 - 17

Abstract

Abstract

Authors in [1] proposed generating method of two-dimensional (2D) quasi orthogonal complete complementary codes (QOCCC) with element order N2. This construction is based on one-dimensional (1D) complete complementary codes (CCC) introduced in [2]. New constructions of CCC with shorter 1D-CCC element length were published recently [3-4]. In this paper former construction is generalized for using any recent 1D-CCC for input which results in 2D-CCC with element of smaller order. Parameter dependences of 2D-QOCCC on 1D-CCC parameters and advantages of QOCCC are discussed

Keywords

  • Quasi orthogonal complete complementary code
  • QOCCC
  • complete complementary code
  • CCC
  • two-dimensional
Open Access

A Proposal of a Multi-Agent System for Adapting Learning Contents to User Competences, Context and Mobile Device

Published Online: 08 Aug 2013
Page range: 18 - 23

Abstract

Abstract

E-learning has been a revolution in recent years in the training field. This, combined with the increased use of the mobile devices has caused the emergence of the m-learning. Hence new problems have appeared in the training field, such as showing correctly some learning contents in a mobile device that has restricted features or taking into account the learner’s context in the learning process, because the learner can be anywhere. Because of this, this paper proposes a new multi-agent system for adapting the learning contents to the learner’s competences, to the learner’s context and to his/her mobile device. The paper also describes in detail the prototype developed for testing the proposed design.

Keywords

  • Adaptation
  • multi-agent system
  • mobile device
  • context
  • competences
Open Access

Introduction to Human Age Estimation Using Face Images

Published Online: 08 Aug 2013
Page range: 24 - 30

Abstract

Abstract

Age estimation is one of the tasks of facial image classification. It can be defined as determination of a person's age or age group from facial images. This paper gives an overview of recent research in facial age estimation. Along with an overview of previous research on this topic, descriptions of basic age estimation models are given: anthropometric model, active appearance model, aging pattern subspace and age manifold.

Keywords

  • biometrics
  • face recognition
  • facial aging
  • age estimation
  • craniofacial morphology
  • aging pattern subspace
  • age manifold
  • active appearance
Open Access

Simulation of Photon Propagation in Tissue Using Matlab

Published Online: 08 Aug 2013
Page range: 31 - 36b

Abstract

Abstract

This paper deals with the light transport, photon trajectory and its radiation in tissue. A model based on Monte Carlo simulation has been implemented in Matlab to get inside into photon interaction with tissue. The project is aimed to non-invasive pulse oximetry measurement of fetal oxygen saturation in the maternal abdomen. One of the fundamental challenges is to ensure a sufficient penetration depth which covers maternal and fetal tissue. This contribution investigates the photon trajectories and analyse the number of photons which stayed in tissue and their radiation distribution. The principle and photon propagation rules, needed for simulation, are presented in this article. Finally the results are compared with literature.

Keywords

  • Monte Carlo simulation
  • photon propagation
  • tissue
  • light transport
Open Access

Smart Home and Erderly People

Published Online: 08 Aug 2013
Page range: 37 - 42

Abstract

Abstract

In this article we purport how advances from the device and technological side have not necessarily been matched with a similar level of development in processing of the information recorded within the living environment from an algorithmic or ‘intelligent’ perspective

Keywords

  • Smart House
  • self-control
  • home automation
  • inteligent control
Open Access

Coating of Cr-V Ledeburitic Steel with CrN Containing 7% of Ag

Published Online: 08 Aug 2013
Page range: 43 - 49

Abstract

Abstract

Samples made from Vanadis 6 PM ledeburitic tool steel were surface machined, ground and mirror polished. Prior the deposition, they were heat treated to a hardness of 60 HRC. CrAg7N-coatings were deposited by magnetron sputtering technique, using pure Cr and Ag targets, in a composite low pressure nitrogen/argon atmosphere and at a temperature of 500 °C. The coatings have an average thickness of 4.3 μm. They grew in a very well visible columnar manner, but, individual silver agglomerates were visible along the columnar crystals, also. The average size of silver agglomerates lies well below 50 nm, e.g. one can suggest that they are capable to be solved and release the Ag atoms to be migrated to the free surface during thermal exposition. The coatings had a good adhesion on the surface - the first critical loads, established by scratch-testing method, ranged between 30 and 39 N.

Keywords

  • CrN-Ag coatings
  • Surface morphology
  • Nanohardness
  • Young´s modulus
  • adhesion
Open Access

Application of Nanotechnology for Anti-Friction Coatings

Published Online: 08 Aug 2013
Page range: 50 - 60

Abstract

Abstract

Different slide-active coatings for thermoplastic surfaces, based on a new binder technology, were investigated for their use as slide element in the automobile interior. The main focus of this paper is the determination of the sliding behaviour of the coated thermoplastics in direct comparison to the uncoated variants. The coatings showed clearly different slide motion properties concerning their friction coefficient and stick-slip behaviour. In a direct comparison with the currently used polymers a clear improvement of slide properties could be achieved.

Keywords

  • slide-active coatings
  • thermoplastics
  • friction
  • solid lubricants
  • stick-slip
  • nano-structured particles
Open Access

Inhomogeneities in the Structure of High Temperature Superconducting Layer

Published Online: 08 Aug 2013
Page range: 61 - 66

Abstract

Abstract

Superconducting layer in coated conductor was investigated to assess the inhomogeneities present in its structure and to get better insight into the effect of inhomogeneities on degradation of electric properties. In the investigation scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron backscattered diffraction, and laser scanning confocal microscopy were used. The results obtained showed good correlation between the density of inhomogeneities across the tape width and the degradation of current transport properties determined by measurements of the current density

Keywords

  • high temperature superconductor
  • characterization of structure
  • inhomogeneities
Open Access

Comparison Of Oxidation Resistance of TiAlN Monolayer Coating And Its NaCo3 Nanostructured Version

Published Online: 08 Aug 2013
Page range: 67 - 72

Abstract

Abstract

The contribution deals with comparison of oxidation resistance of classical TiAlN monolayer coating and its advanced high hard nanostructured and multilayered nACo3 version at elevated temperatures. Both coatings were deposited onto AISI M36 high speed steel using unique LAteral Rotating Cathodes process (LARC®). “In - situ” X-Ray diffraction analysis was employed for determination of the beginning of oxides creation and phase detection at different heating temperatures. Scanning electron microscopy fitted with EDX analysis was used for observation of fracture areas and measurements of coatings and oxide layers thicknesses as well. Determination of chemical composition of coatings surfaces and elemental linescans through the coatings and oxide layers were performed using EDX analysis. All measurements of these coatings were carried out not only before but also after the thermal annealing.

Keywords

  • TiAlN
  • nACo3
  • LARC®
  • In - Situ XRD analysis
  • SEM
  • LSM
Open Access

Structure Analysis of Zn-Al-Mg Coating on Steel Wire

Published Online: 08 Aug 2013
Page range: 73 - 77

Abstract

Abstract

The corrosion resistance of zinc coatings is determined primarily by the thickness of the coating but varies with the severity of environmental conditions. In case of zinc-based alloys for steel coating the phase type and its quantity developed upon solidification determines corrosion resistance as well. In this paper the phase quality and evolution along thickness of the Zn-Al-Mg coating layer was studied by x-ray diffraction analysis. During investigation the coating was removed in controlled manner in several steps. Each individual step of removal was followed with x-ray diffraction measurement and subsequent analysis of x-ray diffraction patterns.

Keywords

  • zinc coatings
  • hot-dipping
  • corrosion resistance
  • zinc-based alloys
  • x-ray diffraction
Open Access

Fault Tree Analysis Optimized by Genetic Algorithms

Published Online: 08 Aug 2013
Page range: 78 - 83

Abstract

Abstract

This paper deals with possibilities of using genetic algorithms in design of costs optimization, which are needed to reach given reliability of technical system, respectively system reliability optimization by given amount of investment costs. In following chapters, there is a described design of new method, which will be later implemented in application and verified on an example.

Causal relationships between system failures and elements faults can be detected by analytic approach, when at first the undesired system fault is identified and its reasons are progressively detected. The reliability of system and its elements is analyzed using method FTA (fault tree analysis) and system is represented by fault trees. In order to optimize costs, respectively reliability, the genetic algorithms are used.

Keywords

  • ault tree analysis
  • fault tree
  • event
  • gate
  • genetic algorithms
  • population
  • objective function
  • selection
  • crossover
  • mutation
Open Access

Impact of Data Characteristics on Feature Selection Techniques Performance

Published Online: 08 Aug 2013
Page range: 84 - 89

Abstract

Abstract

Feature selection is a step in knowledge discovery in databases which takes away most of the time of the entire process. Therefore, the effective implementation of feature selection significantly improves the overall process. This paper suggests examining data characteristics before applying feature selection and hypothesize that data characteristics significantly affect feature selection techniques performance. Our experimental comparison of five previously used feature selection techniques reveals significant difference in feature selection techniques performance when dealing with data sets of different characteristics

Keywords

  • feature selection
  • data characteristics
  • classification accuracy
Open Access

Business Applications Architecture Model Based on Software Product Line Approach

Published Online: 08 Aug 2013
Page range: 90 - 97

Abstract

Abstract

Software product line architecture is one of the most important artifacts defined at the early stage of a product line development process. Since the rest of the products are developed based on the initial product line architecture, it is of high importance to ensure the architecture stability by enabling the software’s evolution possibilities. Industrial evidence shows that companies spend more resources on maintaining and evolving their architecture and products than on the initial development of them. Hence, there is a need for flexible software architecture that stays stable as the requirements evolve. In this paper we propose a structural model, some architecture quality metrics, case-based reasoning methodology to predict the architectural stability and a feature model for business applications. The goal of the proposed architecture model is to develop a framework for business applications development and evaluating the stability of product line architectures in the face of changes in requirements.

Keywords

  • software product lines
  • feature model
  • architecture
  • case-based reasoning
  • metrics
Open Access

Dealing with Mobile Platforms Fragmentation Problem: Ontology Oriented Approach

Published Online: 08 Aug 2013
Page range: 98 - 103

Abstract

Abstract

The available researches that referred mobile platforms fragmentation problem showed that current solutions, although many, converge into several groups that have common advantages and disadvantages and are based on the same principle: code ones, run anywhere. Thus, the new approach that would enable the developers to use native development environments was necessary. This paper introduces an ontology oriented approach that is based on methodological interoperability. Important assumption of the ongoing research presented in this paper is that during the development process the development team should use the same methodology and the same approach while developing for multiple mobile platforms. This will enhance this process with the artifacts reuse possibility according to the ontologically described knowledge.

Keywords

  • mobile
  • development
  • methodology
  • fragmentation
  • interoperability
  • ontology
Open Access

The Proposal of the Process of Safety Analysis for Complex Dynamic Technology Systems

Published Online: 08 Aug 2013
Page range: 104 - 108

Abstract

Abstract

The aim of this article is the proposal of process of the safety analysis for complex dynamic systems in process of the proposal of control system for safety-critical processes. The method of safety analysis depends on various safety-critical states of system which are system are controlled by models. We propose to use the method SQMD for modeling these states. This method combines qualitative and quantitative methods of modeling states and takes advantage of both methods. The model of the proposal is shown in the diagram. The article includes detailed description of the tasks for each step of analysis.

Keywords

  • complex dynamic system
  • qualitative model
  • quantitative model
Open Access

WiFi Roaming Access Point Optimum Assignment in Urban Multi-Sensor

Published Online: 08 Aug 2013
Page range: 109 - 115

Abstract

Abstract

Urban sensor networks produce large amount of data including available WiFi networks information and current GPS location. We work on finding usable information in this WiFi "noise" in urban environments, envisioning the provision of efficient WiFi roaming during travel within the city. We identify the main challenges of such service, and discuss specific issue like finding the optimum sequence of WiFi AP for given route.

Keywords

  • WiFi sequence
  • vertical offload
  • 3G offload
  • urban sensor networks
Open Access

Application of FTIR-ATR Spectroscopy for Determination of Glucose in Hydrolysates of Selected Starches

Published Online: 08 Aug 2013
Page range: 116 - 121

Abstract

Abstract

Fourier transform infrared spectroscopy was evaluated as an easy and simple analytical method for determination of starch residues after enzymatic hydrolysis. Different starch sources were liquefaction by α-amylase enzyme Termamyl SC for 25 minutes in autoclave. In the next step were starches solutions enzymatically hydrolysed by enzyme pollulanase Promozyme® for 24 hours to 60°C water bath. Total glucose in starch hydrolysate was determined using Fourier Transformed Infrared Spectroscopy (FTIR) with ATR accessory with diamante crystal by recording the absorption of different carbohydrate in spectral range from 700 - 4000 cm-1. Based on calibration curves of glucose the release of total glucose in hydrolysates was calculated.

Keywords

  • starch
  • enzymatic hydrolyse
  • sugars
  • FTIR-ATR
Open Access

Ignition Temperature of Dust Layer and Dust Clouds of Wood Pellets

Published Online: 08 Aug 2013
Page range: 122 - 126

Abstract

Abstract

In the production, transport, storage and use of wood pellets forming a flammable and explosive dust. To assess the fire risk of wood pellets was determined ignition temperature of dust layers and dust clouds. We used two commercially produced pellets from wood waste and wood and studied the dependence of ignition temperature on the thickness of dust layer and also observed the ignition temperature dependence of dust clouds from the weight and pressure of air in combustion chamber.

Keywords

  • wood pellets
  • dust layer
  • dust clouds
  • ignition temperature
Open Access

Minimum Ignition Temperature of Wood Dust Layers

Published Online: 08 Aug 2013
Page range: 127 - 131

Abstract

Abstract

Fire characteristic (properties) are used to determine the fire risk and explosion hazard of materials. They are defined as numerical values which describe behavior in the process of burning. They can be determinate by standardized test methods. In this paper is described the most important fire technical characteristic of dust layer (minimum ignition temperature) and the results of standard laboratory method determination for wood dusts, aswell.

Keywords

  • wood dusts
  • fire characteristic
  • minimum ignition temperature
  • dust layer
Open Access

Using Competency Models in Industrial Enterprises

Published Online: 08 Aug 2013
Page range: 132 - 136

Abstract

Abstract

The paper focuses on using competency models in industrial enterprises. This article deals with the theory of competencies, competency models and their utilization. Competency models are a key tool in human resource systems and practice. Managerial competencies enable employees to achieve results, thereby creating value. It follows that managerial competencies aligned with business objectives help foster an organization's success. Organizations must understand their core competency needs - the skills, knowledge, behaviors, and abilities that are necessary for people in key roles to deliver business results. The ability to identify the skills and competencies required for tomorrow’s industry leaders is essential for companies that hope to remain competitive. Identifying appropriate competencies helps senior managers in selecting, developing, and coaching future leaders, as well as mapping career paths and planning management succession.

Keywords

  • managerial competence
  • competency models and hypotheses
Open Access

Challenges of Measuring the Direct Effects of E-Business in SMEs

Published Online: 08 Aug 2013
Page range: 137 - 144

Abstract

Abstract

Development of fast Internet and constant growth of new information and communication technology brought to expansion of interconnections between modern companies and their business partners through new kind of business integration so called electronic business (ebusiness). As the new kind of business connection paradigm has been implemented and started expansion, justification of its use came into the scientific focus. Significant direct and tangible effects of the e-business application have been found and proven in large companies, but in small and medium-sized enterprises (SMEs) these effects have still been the area of exploration. According to latest researches in this field this paper, as a part of dissertation proposal, deals with the issues in the existing methods for e-business direct effects measurement in business processes. This research shows lack of appropriate methods specifically oriented to SMEs. Dissertation proposal is focused on four main problems in measuring future effects of e-business implementation in business processes. The paper emphasizes these issues, whose solution will further lead to new methodology for measuring and assessing direct effects of e-business implementation in SMEs as part of business to business (B2B) communication and the exchange of structured electronic documents in business process cycle, from order to payment.

Keywords

  • e-business
  • cost reduction
  • effects measurement
  • SME
Open Access

People as a Key Resource of Company Performance

Published Online: 08 Aug 2013
Page range: 145 - 149

Abstract

Abstract

Recent years have seen a lot of new management approaches for improving organizational performance such as: total quality management, flat organizations, empowerment, continuous improvement, reengineering, kaizen, team building, and so on. Business leaders today are forced to focus even more on the profitability of their business. During the last several years, companies have initiated Performance Management (PM) systems to improve the quality of their management. In many companies they have succeeded, but in quite a few they have failed. This article presents the importance of Human Resources Management (HRM) and employees as a key factor on success of the company. Authors report that people in organization are a key resource of performance of company. The aim of the article is to analyze literature review and findings of researches with the purpose of completing the PhD theses of authors.

Keywords

  • Performance Management
  • Human Resources Management
  • Performance Appraisal
Open Access

Risk Management and the European Market Infrastructure Regulation (EMIR)

Published Online: 08 Aug 2013
Page range: 150 - 154

Abstract

Abstract

The European Market Infrastructure Regulation (EMIR) is a new act to controle the trade with OTC derivatives as a result of the financial crisis in 2007. The articel describes the main categories of these regulation and clarifies the question, whether these regulation is relevant for industrial companies or not.

Keywords

  • Risk management
  • over the counter (OTC) market
  • derivative regulation
  • EMIR
  • Reporting
  • Clearing
  • central counterparty
  • collateral requirements
Open Access

A Proposed Methodology of Resolving Conflits Within Multicultural Teams in Industrial Enterprises

Published Online: 08 Aug 2013
Page range: 155 - 160

Abstract

Abstract

The main aim of the presented paper is to clarify the need of resolving conflicts within multicultural teams in industrial enterprises, increasing awesome of multiculturalism on Slovakia as necessary part of our life and to suggest the structure of the dissertation thesis. The author base the study on the assumption that extensively developed intercultural relationships lead to mutual understanding between people and consequently to less interpersonal conflicts.The paper is divided in two main chapters. The first one deals with the theoretical bases of given issue, to clarify the concept of multiculturalism. The emphasis is primarily on the issue of conflict resolution within multicultural teams in industrial enterprises. The second one consists of reasoning and continuity of the paper, brief characteristics, goals, hypotheses, theses and benefits valuation.

Keywords

  • globalization
  • multicultural
  • conflit
  • team
  • multicultural team
Open Access

The Strategic Development of Multicultural Competencies Through a Balanced Scorecard Approach

Published Online: 08 Aug 2013
Page range: 161 - 166

Abstract

Abstract

The need to develop a clear understanding of multicultural competencies is essential to fully develop a strategic approach to human capital management (HCM). As Slovak workplaces become more diverse, culture and intercultural management has gained greater significance and the adoption of a strategic approach is now critical to the success and competitive advantage of the organisation. Moreover, it is necessary to address this field of management to ensure the high performance of organisations, especially those operating within a global setting. The focus of the research is on the identification of multicultural competencies in the context of Slovak industrial enterprises to measure and identify linkages between cultural aspects and the strategic business performance.

Keywords

  • Globalisation
  • Multiculturality
  • Industrial Enterprises
  • Balanced Score Card
  • Human Capital Management
  • Performance
Open Access

The Effect of Waveguide Shapes on the Modal Properties and Amplification Factors

Published Online: 08 Aug 2013
Page range: 167 - 172

Abstract

Abstract

Improving of machining process is one of the most important requirements that are expected from the machining methods. In many machining processes, the positive effects of ultrasound are applied. The performance of these machining systems and quality of machining process depends on the correct design of the individual system elements, mainly waveguide. For the correct functioning of the system, the waveguide must have the required dynamic properties - natural frequencies and amplification factors. The waveguide modal properties (natural frequencies, mode shapes) are determined by the numerical simulations using finite element method (FEM) design procedures. The effect of different waveguide shapes (conical, exponential, catenoidal) and their dimensions on modal properties and amplification factors are presented in this paper.

Keywords

  • ultrasonic waveguide
  • modal properties
  • amplification factor
  • finite element method
Open Access

The Impact of Alignment Condition in the Measuring Plan by Using the Software Calypso on the Repeatability of Measured Values

Published Online: 08 Aug 2013
Page range: 173 - 178

Abstract

Abstract

The main goal of this publication is to determine the impact of the alignment condition to the repeatability of measured values. In the experimental work were performed four series of measurements, each contains 25 individual measurements on a single component. The component was measured according to the rules for making the comparison of measured values for repeatability. This comparison of measurement results was made by using statistical methods. A given goal was completely fulfilled. Experimental work has shown a dominant impact of the alignment condition on the measured values.

Keywords

  • CMM
  • repeatability
  • valueA
  • standard deviation
Open Access

Cryogenic Rotary Ultrasonic Machining of Titanium Alloys

Published Online: 08 Aug 2013
Page range: 179 - 185

Abstract

Abstract

Titanium alloys are utilized especially in applications that require a good combination of high strength, low mass and good corrosion resistance in aggressive environments. However, mechanical properties prejudge titanium alloys to hard machinability. Machining of titanium alloys is usually accompanied by cooling with liquids or gasses. One of the most effective cooling approaches is cooling by liquid nitrogen. Liquid nitrogen decreases temperature of tool, but also increases strength, hardness and brittleness of workpiece. One of the most suitable machining methods to machine hard and brittle materials is ultrasonic machining. In this article, rotary ultrasonic machining of titanium alloys under cryogenic conditions is analyzed.

Keywords

  • Cryogenic machining
  • Rotary ultrasonic machining
  • Titanium alloys
  • Liquid nitrogen
Open Access

The Effect of Inner Reinforcing Cores on Natural Frequencies of the Lathe Tool Body

Published Online: 08 Aug 2013
Page range: 186 - 192

Abstract

Abstract

The contribution is mainly focused on research and development of structural modification of machine tools, lathes in particular. The main aim of the modification is to change the modal properties (mode shapes, natural frequencies) of the lathe tool. The main objective of the contribution will be to formulate, mathematical analyse and evaluate the proposed methods and procedures for structural modifications of the tool, represented by beam body. A modification of modal properties by insertion of beam cores into beam body is studied in this paper. In this paper, the effect of material properties and geometrical parameters of reinforcing cores on natural frequencies of beam body is presented. The implementation will bring benefit on machine productivity, decreasing the machine tool wear and in many cases it will lead to better conditions in the cutting process.

Keywords

  • lathe tool
  • modal properties
  • Euler-Bernoulli beam theory
  • vibration
  • reinforcement
Open Access

Development of Surface Roughness in Hard Turning of 100Cr6 Using Mixed Ceramic Cutting Tool with Wiper Geometry and Conventional Geometry

Published Online: 08 Aug 2013
Page range: 193 - 198

Abstract

Abstract

Hard turning has been applied in machining since the early 1980s. There is an effort to substitute finish grinding by hard machining, because of machining by cutting tool with defined geometry. For machining of hardened steels (up to 45 HRC) are used two different cutting materials. PCBN are used the most for discontinuous machining of hardened steel (up to 63 HRC) and mixed ceramic tools, which are used in the experiment. This paper reports a development of surface roughness parameters when using wiper tool geometry of mixed ceramic tool and conventional geometry of mixed ceramic tool in hard turning. Roughness parameters (Ra, Rz, Rsk, Rku, RSm, Rdq) are measured when changing the feed, depth of cut and cutting speed are constant.

Keywords

  • hard turning
  • mixed ceramic tool
  • tool geometry
  • surface roughness parameters
0 Articles
Open Access

Contributions to Improve Online Learning Through Adaptive Hypermedia Techniques

Published Online: 08 Aug 2013
Page range: 1 - 6

Abstract

Abstract

The personalization of learning through the automatic adaptation of the educational process, especially for the contents, is regarded as an important and necessary step for the improvement of education in the future. It is believed that through individualization get improved efficiency, increased speed and quality of learning for students and by automating the process, improved efficiency, better resource utilization, scalability of the process learning. To achieve this goal we have developed different strategies. One of them are looking for Adaptive Hypermedia Systems adjust all contents in a atuomática to the characteristics of each user.

Keywords

  • Adaptive Hypermedia System
  • user modelling
  • educational dataminig
  • learning analytics
Open Access

Data Portability Among Providers o Platform as a Service

Published Online: 08 Aug 2013
Page range: 7 - 11

Abstract

Abstract

Platform as a service model has certain obstacles, including data lock-in. It is expensive and time-consuming to move data to the alternative providers. This paper presents data storage options in platform as a service offers and identifies the most common data portability problems between various commercial providers of platform as a service. There are differences among their storage models, data types, remote APIs for data manipulation and query languages. Representing data models of platform as a service and data mappings by means of ontology can provide a common layer to achieve data portability among different cloud providers.

Keywords

  • data portability
  • platform as a service
  • Cloud Computing
Open Access

Generalized Construction of Two-Dimensional Quasi Complete Complementary Codes

Published Online: 08 Aug 2013
Page range: 12 - 17

Abstract

Abstract

Authors in [1] proposed generating method of two-dimensional (2D) quasi orthogonal complete complementary codes (QOCCC) with element order N2. This construction is based on one-dimensional (1D) complete complementary codes (CCC) introduced in [2]. New constructions of CCC with shorter 1D-CCC element length were published recently [3-4]. In this paper former construction is generalized for using any recent 1D-CCC for input which results in 2D-CCC with element of smaller order. Parameter dependences of 2D-QOCCC on 1D-CCC parameters and advantages of QOCCC are discussed

Keywords

  • Quasi orthogonal complete complementary code
  • QOCCC
  • complete complementary code
  • CCC
  • two-dimensional
Open Access

A Proposal of a Multi-Agent System for Adapting Learning Contents to User Competences, Context and Mobile Device

Published Online: 08 Aug 2013
Page range: 18 - 23

Abstract

Abstract

E-learning has been a revolution in recent years in the training field. This, combined with the increased use of the mobile devices has caused the emergence of the m-learning. Hence new problems have appeared in the training field, such as showing correctly some learning contents in a mobile device that has restricted features or taking into account the learner’s context in the learning process, because the learner can be anywhere. Because of this, this paper proposes a new multi-agent system for adapting the learning contents to the learner’s competences, to the learner’s context and to his/her mobile device. The paper also describes in detail the prototype developed for testing the proposed design.

Keywords

  • Adaptation
  • multi-agent system
  • mobile device
  • context
  • competences
Open Access

Introduction to Human Age Estimation Using Face Images

Published Online: 08 Aug 2013
Page range: 24 - 30

Abstract

Abstract

Age estimation is one of the tasks of facial image classification. It can be defined as determination of a person's age or age group from facial images. This paper gives an overview of recent research in facial age estimation. Along with an overview of previous research on this topic, descriptions of basic age estimation models are given: anthropometric model, active appearance model, aging pattern subspace and age manifold.

Keywords

  • biometrics
  • face recognition
  • facial aging
  • age estimation
  • craniofacial morphology
  • aging pattern subspace
  • age manifold
  • active appearance
Open Access

Simulation of Photon Propagation in Tissue Using Matlab

Published Online: 08 Aug 2013
Page range: 31 - 36b

Abstract

Abstract

This paper deals with the light transport, photon trajectory and its radiation in tissue. A model based on Monte Carlo simulation has been implemented in Matlab to get inside into photon interaction with tissue. The project is aimed to non-invasive pulse oximetry measurement of fetal oxygen saturation in the maternal abdomen. One of the fundamental challenges is to ensure a sufficient penetration depth which covers maternal and fetal tissue. This contribution investigates the photon trajectories and analyse the number of photons which stayed in tissue and their radiation distribution. The principle and photon propagation rules, needed for simulation, are presented in this article. Finally the results are compared with literature.

Keywords

  • Monte Carlo simulation
  • photon propagation
  • tissue
  • light transport
Open Access

Smart Home and Erderly People

Published Online: 08 Aug 2013
Page range: 37 - 42

Abstract

Abstract

In this article we purport how advances from the device and technological side have not necessarily been matched with a similar level of development in processing of the information recorded within the living environment from an algorithmic or ‘intelligent’ perspective

Keywords

  • Smart House
  • self-control
  • home automation
  • inteligent control
Open Access

Coating of Cr-V Ledeburitic Steel with CrN Containing 7% of Ag

Published Online: 08 Aug 2013
Page range: 43 - 49

Abstract

Abstract

Samples made from Vanadis 6 PM ledeburitic tool steel were surface machined, ground and mirror polished. Prior the deposition, they were heat treated to a hardness of 60 HRC. CrAg7N-coatings were deposited by magnetron sputtering technique, using pure Cr and Ag targets, in a composite low pressure nitrogen/argon atmosphere and at a temperature of 500 °C. The coatings have an average thickness of 4.3 μm. They grew in a very well visible columnar manner, but, individual silver agglomerates were visible along the columnar crystals, also. The average size of silver agglomerates lies well below 50 nm, e.g. one can suggest that they are capable to be solved and release the Ag atoms to be migrated to the free surface during thermal exposition. The coatings had a good adhesion on the surface - the first critical loads, established by scratch-testing method, ranged between 30 and 39 N.

Keywords

  • CrN-Ag coatings
  • Surface morphology
  • Nanohardness
  • Young´s modulus
  • adhesion
Open Access

Application of Nanotechnology for Anti-Friction Coatings

Published Online: 08 Aug 2013
Page range: 50 - 60

Abstract

Abstract

Different slide-active coatings for thermoplastic surfaces, based on a new binder technology, were investigated for their use as slide element in the automobile interior. The main focus of this paper is the determination of the sliding behaviour of the coated thermoplastics in direct comparison to the uncoated variants. The coatings showed clearly different slide motion properties concerning their friction coefficient and stick-slip behaviour. In a direct comparison with the currently used polymers a clear improvement of slide properties could be achieved.

Keywords

  • slide-active coatings
  • thermoplastics
  • friction
  • solid lubricants
  • stick-slip
  • nano-structured particles
Open Access

Inhomogeneities in the Structure of High Temperature Superconducting Layer

Published Online: 08 Aug 2013
Page range: 61 - 66

Abstract

Abstract

Superconducting layer in coated conductor was investigated to assess the inhomogeneities present in its structure and to get better insight into the effect of inhomogeneities on degradation of electric properties. In the investigation scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron backscattered diffraction, and laser scanning confocal microscopy were used. The results obtained showed good correlation between the density of inhomogeneities across the tape width and the degradation of current transport properties determined by measurements of the current density

Keywords

  • high temperature superconductor
  • characterization of structure
  • inhomogeneities
Open Access

Comparison Of Oxidation Resistance of TiAlN Monolayer Coating And Its NaCo3 Nanostructured Version

Published Online: 08 Aug 2013
Page range: 67 - 72

Abstract

Abstract

The contribution deals with comparison of oxidation resistance of classical TiAlN monolayer coating and its advanced high hard nanostructured and multilayered nACo3 version at elevated temperatures. Both coatings were deposited onto AISI M36 high speed steel using unique LAteral Rotating Cathodes process (LARC®). “In - situ” X-Ray diffraction analysis was employed for determination of the beginning of oxides creation and phase detection at different heating temperatures. Scanning electron microscopy fitted with EDX analysis was used for observation of fracture areas and measurements of coatings and oxide layers thicknesses as well. Determination of chemical composition of coatings surfaces and elemental linescans through the coatings and oxide layers were performed using EDX analysis. All measurements of these coatings were carried out not only before but also after the thermal annealing.

Keywords

  • TiAlN
  • nACo3
  • LARC®
  • In - Situ XRD analysis
  • SEM
  • LSM
Open Access

Structure Analysis of Zn-Al-Mg Coating on Steel Wire

Published Online: 08 Aug 2013
Page range: 73 - 77

Abstract

Abstract

The corrosion resistance of zinc coatings is determined primarily by the thickness of the coating but varies with the severity of environmental conditions. In case of zinc-based alloys for steel coating the phase type and its quantity developed upon solidification determines corrosion resistance as well. In this paper the phase quality and evolution along thickness of the Zn-Al-Mg coating layer was studied by x-ray diffraction analysis. During investigation the coating was removed in controlled manner in several steps. Each individual step of removal was followed with x-ray diffraction measurement and subsequent analysis of x-ray diffraction patterns.

Keywords

  • zinc coatings
  • hot-dipping
  • corrosion resistance
  • zinc-based alloys
  • x-ray diffraction
Open Access

Fault Tree Analysis Optimized by Genetic Algorithms

Published Online: 08 Aug 2013
Page range: 78 - 83

Abstract

Abstract

This paper deals with possibilities of using genetic algorithms in design of costs optimization, which are needed to reach given reliability of technical system, respectively system reliability optimization by given amount of investment costs. In following chapters, there is a described design of new method, which will be later implemented in application and verified on an example.

Causal relationships between system failures and elements faults can be detected by analytic approach, when at first the undesired system fault is identified and its reasons are progressively detected. The reliability of system and its elements is analyzed using method FTA (fault tree analysis) and system is represented by fault trees. In order to optimize costs, respectively reliability, the genetic algorithms are used.

Keywords

  • ault tree analysis
  • fault tree
  • event
  • gate
  • genetic algorithms
  • population
  • objective function
  • selection
  • crossover
  • mutation
Open Access

Impact of Data Characteristics on Feature Selection Techniques Performance

Published Online: 08 Aug 2013
Page range: 84 - 89

Abstract

Abstract

Feature selection is a step in knowledge discovery in databases which takes away most of the time of the entire process. Therefore, the effective implementation of feature selection significantly improves the overall process. This paper suggests examining data characteristics before applying feature selection and hypothesize that data characteristics significantly affect feature selection techniques performance. Our experimental comparison of five previously used feature selection techniques reveals significant difference in feature selection techniques performance when dealing with data sets of different characteristics

Keywords

  • feature selection
  • data characteristics
  • classification accuracy
Open Access

Business Applications Architecture Model Based on Software Product Line Approach

Published Online: 08 Aug 2013
Page range: 90 - 97

Abstract

Abstract

Software product line architecture is one of the most important artifacts defined at the early stage of a product line development process. Since the rest of the products are developed based on the initial product line architecture, it is of high importance to ensure the architecture stability by enabling the software’s evolution possibilities. Industrial evidence shows that companies spend more resources on maintaining and evolving their architecture and products than on the initial development of them. Hence, there is a need for flexible software architecture that stays stable as the requirements evolve. In this paper we propose a structural model, some architecture quality metrics, case-based reasoning methodology to predict the architectural stability and a feature model for business applications. The goal of the proposed architecture model is to develop a framework for business applications development and evaluating the stability of product line architectures in the face of changes in requirements.

Keywords

  • software product lines
  • feature model
  • architecture
  • case-based reasoning
  • metrics
Open Access

Dealing with Mobile Platforms Fragmentation Problem: Ontology Oriented Approach

Published Online: 08 Aug 2013
Page range: 98 - 103

Abstract

Abstract

The available researches that referred mobile platforms fragmentation problem showed that current solutions, although many, converge into several groups that have common advantages and disadvantages and are based on the same principle: code ones, run anywhere. Thus, the new approach that would enable the developers to use native development environments was necessary. This paper introduces an ontology oriented approach that is based on methodological interoperability. Important assumption of the ongoing research presented in this paper is that during the development process the development team should use the same methodology and the same approach while developing for multiple mobile platforms. This will enhance this process with the artifacts reuse possibility according to the ontologically described knowledge.

Keywords

  • mobile
  • development
  • methodology
  • fragmentation
  • interoperability
  • ontology
Open Access

The Proposal of the Process of Safety Analysis for Complex Dynamic Technology Systems

Published Online: 08 Aug 2013
Page range: 104 - 108

Abstract

Abstract

The aim of this article is the proposal of process of the safety analysis for complex dynamic systems in process of the proposal of control system for safety-critical processes. The method of safety analysis depends on various safety-critical states of system which are system are controlled by models. We propose to use the method SQMD for modeling these states. This method combines qualitative and quantitative methods of modeling states and takes advantage of both methods. The model of the proposal is shown in the diagram. The article includes detailed description of the tasks for each step of analysis.

Keywords

  • complex dynamic system
  • qualitative model
  • quantitative model
Open Access

WiFi Roaming Access Point Optimum Assignment in Urban Multi-Sensor

Published Online: 08 Aug 2013
Page range: 109 - 115

Abstract

Abstract

Urban sensor networks produce large amount of data including available WiFi networks information and current GPS location. We work on finding usable information in this WiFi "noise" in urban environments, envisioning the provision of efficient WiFi roaming during travel within the city. We identify the main challenges of such service, and discuss specific issue like finding the optimum sequence of WiFi AP for given route.

Keywords

  • WiFi sequence
  • vertical offload
  • 3G offload
  • urban sensor networks
Open Access

Application of FTIR-ATR Spectroscopy for Determination of Glucose in Hydrolysates of Selected Starches

Published Online: 08 Aug 2013
Page range: 116 - 121

Abstract

Abstract

Fourier transform infrared spectroscopy was evaluated as an easy and simple analytical method for determination of starch residues after enzymatic hydrolysis. Different starch sources were liquefaction by α-amylase enzyme Termamyl SC for 25 minutes in autoclave. In the next step were starches solutions enzymatically hydrolysed by enzyme pollulanase Promozyme® for 24 hours to 60°C water bath. Total glucose in starch hydrolysate was determined using Fourier Transformed Infrared Spectroscopy (FTIR) with ATR accessory with diamante crystal by recording the absorption of different carbohydrate in spectral range from 700 - 4000 cm-1. Based on calibration curves of glucose the release of total glucose in hydrolysates was calculated.

Keywords

  • starch
  • enzymatic hydrolyse
  • sugars
  • FTIR-ATR
Open Access

Ignition Temperature of Dust Layer and Dust Clouds of Wood Pellets

Published Online: 08 Aug 2013
Page range: 122 - 126

Abstract

Abstract

In the production, transport, storage and use of wood pellets forming a flammable and explosive dust. To assess the fire risk of wood pellets was determined ignition temperature of dust layers and dust clouds. We used two commercially produced pellets from wood waste and wood and studied the dependence of ignition temperature on the thickness of dust layer and also observed the ignition temperature dependence of dust clouds from the weight and pressure of air in combustion chamber.

Keywords

  • wood pellets
  • dust layer
  • dust clouds
  • ignition temperature
Open Access

Minimum Ignition Temperature of Wood Dust Layers

Published Online: 08 Aug 2013
Page range: 127 - 131

Abstract

Abstract

Fire characteristic (properties) are used to determine the fire risk and explosion hazard of materials. They are defined as numerical values which describe behavior in the process of burning. They can be determinate by standardized test methods. In this paper is described the most important fire technical characteristic of dust layer (minimum ignition temperature) and the results of standard laboratory method determination for wood dusts, aswell.

Keywords

  • wood dusts
  • fire characteristic
  • minimum ignition temperature
  • dust layer
Open Access

Using Competency Models in Industrial Enterprises

Published Online: 08 Aug 2013
Page range: 132 - 136

Abstract

Abstract

The paper focuses on using competency models in industrial enterprises. This article deals with the theory of competencies, competency models and their utilization. Competency models are a key tool in human resource systems and practice. Managerial competencies enable employees to achieve results, thereby creating value. It follows that managerial competencies aligned with business objectives help foster an organization's success. Organizations must understand their core competency needs - the skills, knowledge, behaviors, and abilities that are necessary for people in key roles to deliver business results. The ability to identify the skills and competencies required for tomorrow’s industry leaders is essential for companies that hope to remain competitive. Identifying appropriate competencies helps senior managers in selecting, developing, and coaching future leaders, as well as mapping career paths and planning management succession.

Keywords

  • managerial competence
  • competency models and hypotheses
Open Access

Challenges of Measuring the Direct Effects of E-Business in SMEs

Published Online: 08 Aug 2013
Page range: 137 - 144

Abstract

Abstract

Development of fast Internet and constant growth of new information and communication technology brought to expansion of interconnections between modern companies and their business partners through new kind of business integration so called electronic business (ebusiness). As the new kind of business connection paradigm has been implemented and started expansion, justification of its use came into the scientific focus. Significant direct and tangible effects of the e-business application have been found and proven in large companies, but in small and medium-sized enterprises (SMEs) these effects have still been the area of exploration. According to latest researches in this field this paper, as a part of dissertation proposal, deals with the issues in the existing methods for e-business direct effects measurement in business processes. This research shows lack of appropriate methods specifically oriented to SMEs. Dissertation proposal is focused on four main problems in measuring future effects of e-business implementation in business processes. The paper emphasizes these issues, whose solution will further lead to new methodology for measuring and assessing direct effects of e-business implementation in SMEs as part of business to business (B2B) communication and the exchange of structured electronic documents in business process cycle, from order to payment.

Keywords

  • e-business
  • cost reduction
  • effects measurement
  • SME
Open Access

People as a Key Resource of Company Performance

Published Online: 08 Aug 2013
Page range: 145 - 149

Abstract

Abstract

Recent years have seen a lot of new management approaches for improving organizational performance such as: total quality management, flat organizations, empowerment, continuous improvement, reengineering, kaizen, team building, and so on. Business leaders today are forced to focus even more on the profitability of their business. During the last several years, companies have initiated Performance Management (PM) systems to improve the quality of their management. In many companies they have succeeded, but in quite a few they have failed. This article presents the importance of Human Resources Management (HRM) and employees as a key factor on success of the company. Authors report that people in organization are a key resource of performance of company. The aim of the article is to analyze literature review and findings of researches with the purpose of completing the PhD theses of authors.

Keywords

  • Performance Management
  • Human Resources Management
  • Performance Appraisal
Open Access

Risk Management and the European Market Infrastructure Regulation (EMIR)

Published Online: 08 Aug 2013
Page range: 150 - 154

Abstract

Abstract

The European Market Infrastructure Regulation (EMIR) is a new act to controle the trade with OTC derivatives as a result of the financial crisis in 2007. The articel describes the main categories of these regulation and clarifies the question, whether these regulation is relevant for industrial companies or not.

Keywords

  • Risk management
  • over the counter (OTC) market
  • derivative regulation
  • EMIR
  • Reporting
  • Clearing
  • central counterparty
  • collateral requirements
Open Access

A Proposed Methodology of Resolving Conflits Within Multicultural Teams in Industrial Enterprises

Published Online: 08 Aug 2013
Page range: 155 - 160

Abstract

Abstract

The main aim of the presented paper is to clarify the need of resolving conflicts within multicultural teams in industrial enterprises, increasing awesome of multiculturalism on Slovakia as necessary part of our life and to suggest the structure of the dissertation thesis. The author base the study on the assumption that extensively developed intercultural relationships lead to mutual understanding between people and consequently to less interpersonal conflicts.The paper is divided in two main chapters. The first one deals with the theoretical bases of given issue, to clarify the concept of multiculturalism. The emphasis is primarily on the issue of conflict resolution within multicultural teams in industrial enterprises. The second one consists of reasoning and continuity of the paper, brief characteristics, goals, hypotheses, theses and benefits valuation.

Keywords

  • globalization
  • multicultural
  • conflit
  • team
  • multicultural team
Open Access

The Strategic Development of Multicultural Competencies Through a Balanced Scorecard Approach

Published Online: 08 Aug 2013
Page range: 161 - 166

Abstract

Abstract

The need to develop a clear understanding of multicultural competencies is essential to fully develop a strategic approach to human capital management (HCM). As Slovak workplaces become more diverse, culture and intercultural management has gained greater significance and the adoption of a strategic approach is now critical to the success and competitive advantage of the organisation. Moreover, it is necessary to address this field of management to ensure the high performance of organisations, especially those operating within a global setting. The focus of the research is on the identification of multicultural competencies in the context of Slovak industrial enterprises to measure and identify linkages between cultural aspects and the strategic business performance.

Keywords

  • Globalisation
  • Multiculturality
  • Industrial Enterprises
  • Balanced Score Card
  • Human Capital Management
  • Performance
Open Access

The Effect of Waveguide Shapes on the Modal Properties and Amplification Factors

Published Online: 08 Aug 2013
Page range: 167 - 172

Abstract

Abstract

Improving of machining process is one of the most important requirements that are expected from the machining methods. In many machining processes, the positive effects of ultrasound are applied. The performance of these machining systems and quality of machining process depends on the correct design of the individual system elements, mainly waveguide. For the correct functioning of the system, the waveguide must have the required dynamic properties - natural frequencies and amplification factors. The waveguide modal properties (natural frequencies, mode shapes) are determined by the numerical simulations using finite element method (FEM) design procedures. The effect of different waveguide shapes (conical, exponential, catenoidal) and their dimensions on modal properties and amplification factors are presented in this paper.

Keywords

  • ultrasonic waveguide
  • modal properties
  • amplification factor
  • finite element method
Open Access

The Impact of Alignment Condition in the Measuring Plan by Using the Software Calypso on the Repeatability of Measured Values

Published Online: 08 Aug 2013
Page range: 173 - 178

Abstract

Abstract

The main goal of this publication is to determine the impact of the alignment condition to the repeatability of measured values. In the experimental work were performed four series of measurements, each contains 25 individual measurements on a single component. The component was measured according to the rules for making the comparison of measured values for repeatability. This comparison of measurement results was made by using statistical methods. A given goal was completely fulfilled. Experimental work has shown a dominant impact of the alignment condition on the measured values.

Keywords

  • CMM
  • repeatability
  • valueA
  • standard deviation
Open Access

Cryogenic Rotary Ultrasonic Machining of Titanium Alloys

Published Online: 08 Aug 2013
Page range: 179 - 185

Abstract

Abstract

Titanium alloys are utilized especially in applications that require a good combination of high strength, low mass and good corrosion resistance in aggressive environments. However, mechanical properties prejudge titanium alloys to hard machinability. Machining of titanium alloys is usually accompanied by cooling with liquids or gasses. One of the most effective cooling approaches is cooling by liquid nitrogen. Liquid nitrogen decreases temperature of tool, but also increases strength, hardness and brittleness of workpiece. One of the most suitable machining methods to machine hard and brittle materials is ultrasonic machining. In this article, rotary ultrasonic machining of titanium alloys under cryogenic conditions is analyzed.

Keywords

  • Cryogenic machining
  • Rotary ultrasonic machining
  • Titanium alloys
  • Liquid nitrogen
Open Access

The Effect of Inner Reinforcing Cores on Natural Frequencies of the Lathe Tool Body

Published Online: 08 Aug 2013
Page range: 186 - 192

Abstract

Abstract

The contribution is mainly focused on research and development of structural modification of machine tools, lathes in particular. The main aim of the modification is to change the modal properties (mode shapes, natural frequencies) of the lathe tool. The main objective of the contribution will be to formulate, mathematical analyse and evaluate the proposed methods and procedures for structural modifications of the tool, represented by beam body. A modification of modal properties by insertion of beam cores into beam body is studied in this paper. In this paper, the effect of material properties and geometrical parameters of reinforcing cores on natural frequencies of beam body is presented. The implementation will bring benefit on machine productivity, decreasing the machine tool wear and in many cases it will lead to better conditions in the cutting process.

Keywords

  • lathe tool
  • modal properties
  • Euler-Bernoulli beam theory
  • vibration
  • reinforcement
Open Access

Development of Surface Roughness in Hard Turning of 100Cr6 Using Mixed Ceramic Cutting Tool with Wiper Geometry and Conventional Geometry

Published Online: 08 Aug 2013
Page range: 193 - 198

Abstract

Abstract

Hard turning has been applied in machining since the early 1980s. There is an effort to substitute finish grinding by hard machining, because of machining by cutting tool with defined geometry. For machining of hardened steels (up to 45 HRC) are used two different cutting materials. PCBN are used the most for discontinuous machining of hardened steel (up to 63 HRC) and mixed ceramic tools, which are used in the experiment. This paper reports a development of surface roughness parameters when using wiper tool geometry of mixed ceramic tool and conventional geometry of mixed ceramic tool in hard turning. Roughness parameters (Ra, Rz, Rsk, Rku, RSm, Rdq) are measured when changing the feed, depth of cut and cutting speed are constant.

Keywords

  • hard turning
  • mixed ceramic tool
  • tool geometry
  • surface roughness parameters