bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen-Induced Ductility Loss in Cast Irons
Authors: Usuda Teruki , Matsuno K. , Matsunaga Hisao , Yanase Keiji , Endo Masahiro
Published: March 2013

Effect of hydrogen-charging was investigated with respect to the tensile properties of three types of cast irons: JIS FCD400, FCD450 and FCD700. In this study, hydrogen charging led to a marked ductility loss in all the cast irons. The thermal desorption spectroscopy and the hydrogen microprint technique revealed that, in the hydrogen-charged specimens, most of solute hydrogen was diffusive and mainly segregated at graphite, graphite/matrix interface zone and pearlite. In the fracture process of non-charged specimen, neighboring graphites were interconnected with each other mainly by ductile dimple fracture. On the other hand, in the fracture process of hydrogen-charged specimen, the graphites were interconnected by cracks. The difference in the fracture morphology between the non-charged and the hydrogen-charged specimens is attributed to the presence of diffusive hydrogen in graphite and graphite/matrix interface. During early stage of fracture process in hydrogen-charged specimen, the interspace between graphite and matrix is filled with hydrogen gas, which leads to the ductility loss of matrix in the vicinity of graphite. Even after the initiation of crack from graphite, hydrogen is continuously outgassed from graphite and supplied to the crack tip. Therefore, concerning the hydrogen effect on the strength of cast irons, a role of subsurface graphite as a “local hydrogen supplier” should be taken into consideration.
The Effect of Pt Addition on the Structure and Magnetic Properties of Melt-Spun Fe80–xPtxB20 Alloys
Authors: Yin C.L. , Li Yan Hui , Jia X.J. , Zhang Wei
Published: March 2013

The structure and magnetic properties of the melt-spun Fe80–xPtxB20 (x = 0 – 20) alloys have been investigated. The amorphous phase was obtained for the alloys with x = 0 and 5, while the mixed structure consisting of amorphous and fcc-FePt phases was formed for the alloys with x = 10, 15 and 20. The annealed alloys consist of α-Fe + Fe3B phases for x = 0 and 5, Fe3B + Fe2B + fcc-FePt phases for x=10, and Fe2B + fcc-FePt + L10-FePt phases for x = 15 and 20, respectively. The alloys with x = 15 and 20 exhibited hard magnetic characterization after annealing. The coercivity increased with increasing Pt content.
Effects of Lanthanide Substitution on the Sintering Behavior of Bismuth Titanate Ceramics Prepared by the Chemical Coprecipitation Method
Authors: Nakatsuka Kohei , Ohta Yoshio , Kitayama Mikito
Published: March 2013

Bi4-xLnxTi3O12 (Ln = La, Nd or Gd; x = 0, 0.25, 0.5, 0.75 or 1.0) fine powders were prepared by the chemical coprecipitation method. Suitable calcination temperature for each powder was determined. The effects of Ln-substitution on the sintering behaviors, crystal structures, lattice constants and microstructures of sintered bodies were investigated. The crystallization temperature was significantly influenced by lanthanide elements and their amounts, and thus, a suitable temperature for calcination was determined for each substitution. Each calcined powder was milled and fired at 950, 1000, 1050 or 1100°C for 2 hr. It was found that the Ln-substitution drastically inhibited both sintering and grain growth, although the effect was not consistent with the order of Ln ionic radii.
Development of Silicon Nitride Porous Bodies with Micro-Macro Complex Pore Structure for the Application of the ‘Bio-Filter’
Authors: Ueta Wataru , Ohta Yoshio , Kitayama Mikito
Published: March 2013

In order to develop the ‘Bio-filter’, Si3N4 porous bodies with micro-macro complex pore structure were fabricated. The micro-pores were successfully introduced by inserting PE meshes between the green tapes. Micro-pore size was controlled by adding a small amount of the β-Si3N4 ‘seed’ particles to the α-Si3N4 raw powder. It is expected that the aerobic microbes colonize along the micro-pores consuming dissolved oxygen, which makes the anaerobic ones colonized within the micro-pores to develop the microbe consortium. In this study, this concept was verified by using the S. cerevisiae and B. bifidum as the aerobic and anaerobic microbes, respectively.
Effects of Minor Si Addition on Glass Formation and Thermal Stability of Ni Free Ti-Based Bulk Metallic Glass
Authors: Zhu Sheng Li , Xie Guo Qiang , Qin Feng Xiang , Wang Xin Min
Published: March 2013

The effects of small amounts of Si on the glass-forming ability, thermal stability and mechanical property of a TiZrCuPdSn bulk metallic glass were investigated. The addition of Si caused the decrease of glass-forming ability and the increase of the supercooled liquid (SCL) region. With 2 at.% Si addition, a significant SCL region of 80 K was obtained, which indicated high thermal stability of the glassy alloy and was in favor of secondary working by viscous flow deformation. With increasing Si content, the plasticity decreased.
Peroxidase and Toluidine Blue-Incorporated DNA Bio-Polyion Complex Film as Biosensing Layer for Hydrogen Peroxide Determination
Authors: Gu Ting Ting , Xia Hong Qi , Wang Jian Li , Yang Da Wei , Zhao Yang , Liu Mo Han , Fang Zhi Gang
Published: March 2013

Horseradish peroxidase (HRP) and toluidine blue (TB) were incorporated in polyion complex membrane composed of double stranded DNA(dsDNA) and chitosan prepared on the surface of an glassy carbon (GC) disk electrode to fabricate highly sensitive and selective reagentless H2O2 biosensor. The embedded-TB in the DNA/chitosan membrane exhibited excellent electrochemical redox property with an electron transfer rate constant of 3.12 ± 0.5 sec−1, and shuttled electron effectively from the base GC electrode to catalytic center of the HRP. Under the applied potential of -0.22V (versus Ag/AgCl) and pH 7.0, the resulting electrode (HRP/DNA–TB/chitosan/GCE) exhibited rapid (<10 s) and sensitive response to H2O2. The calibration curve of H2O2, plotting steady-state cathodic current versus H2O2 concentration, was linear up to 0.1mM with a detection limit of 1 μM H2O2 (S/N = 3). The H2O2 response was scarcely interfered by ascorbic acid and uric acid, which potentially reduce oxidized intermediate of the HRP and interfere with the response of peroxidase-based electrodes.
Effect of Different Wire Electrodes on the Performance of WEDM
Authors: Kapoor Jatinder , Khamba Jaimal Singh , Singh Sehijpal
Published: March 2013

In this paper, the effect of different wire electrodes used in wire electrical discharge machining (WEDM) on the machining characteristics of AISI D3 die steel has been presented. Three process parameters, namely type of wire (brass wire, zinc coated wire and composite wire), pulse on time and peak current have been considered. The process performance is measured in terms of cutting speed and surface roughness. The research outcome will identify the important parameters and their effect on performance characteristics while machining AISI D3 material with different wire electrodes. The analysis of variance (ANOVA) of multilevel factorial design indicated that all the selected parameters have significant effect on the performance characteristics. The study indicated the improvement in surface roughness with brass wire over other wires. Maximum cutting speed was obtained with composite wire as compared to zinc coated and brass wire. Additionally, scanning electron microscope (SEM) examination highlighted important features of machined work piece surface.
Erosion Characteristics of HVOF Developed Cr3C2-NiCr and WC-Co Coatings
Authors: Singh Hazoor , Sidhu Buta Singh
Published: March 2013

Erosion behavior of the high velocity oxy fuel (HVOF) deposited Cr3C2-NiCr and WC-Co coatings on boiler tube steels was evaluated. The solid particle erosion study was conducted, using an air jet erosion test rig at a velocity of 26 m/s and impingement angles of 300 and 900, on uncoated as well as HVOF spray coated boiler tube steels at 250°C. The coatings are significantly harder than the substrate steel and less porous. Scanning electron microscopy (SEM) technique was used to analyze the eroded surface. Mass loss of the coatings was found higher than the boiler tube steel.
The System of Visual Assessment of Technical State of Underwater Objects
Authors: Olejnik Adam
Published: March 2013

This material presents the results of works implemented so far at the Department of Underwater Work Technology of the Polish Naval Academy in Gdynia, Poland, within the project No. O N502 274039, focused on an attempt to prepare theoretical assumptions for the visual diagnostics system for underwater objects. The main accomplishments until now have been the preparation of a mathematical model allowing specification of dimensions of photographed underwater objects and construction of a prototype underwater photogrammetric camera. The said device is used for collecting data required in the mathematical model. Moreover, the project involved carrying out experiments which provided the basis for determining optical parameters of the constructed camera. In prospect, the works on the application for the operation of the photogrammetric camera will be accompanied by construction works on a visual assessment system allowing for quantitative and qualitative verification of the state of examined underwater objects.
The Study of Distributed Manufacturing Control System Self-Configuration
Authors: Bachula Kamila , Zajac Jerzy
Published: March 2013

The paper describes a three-stage framework for modelling of a discrete manufacturing system. It presents the self-configuration procedure for a distributed manufacturing control system with use of this framework. The procedure allows for the construction of the plug and produce distributed manufacturing control system, which requires the integration of unified, easy to reconfigure cooperative agents. Arena simulation environment (by Rockwell Automation) is used for examining the procedure.
Distance Measurement Using a Stereo Vision System
Authors: Żak Bogdan , Hożyń Stanisław
Published: March 2013

In this paper the attempt to make an analysis of distance measurement using a stereo vision system was presented. Main emphasis was placed on the geometric camera calibration. The classical method based on the specially prepared calibration pattern with known dimensions and position in a certain coordinates system was performed. Finally, the metric information obtained from images was presented.
Optoelectronic Systems on Board of Unmanned Surface Vehicle 'Edredon'
Authors: Kitowski Zygmunt
Published: March 2013

Electronic visual observation devices are the most important ways to conduct navigation and the observation of sea navigation in bad weather and at night. The use of unmanned craft requires the use of different kinds of sensors for navigation and the execution of the tasks posed to them during their operational use. For navigation, especially the combat system is an indispensable optoelektronic head with termovision equipment. In the article, discuss problems associated the equipment of the first Polish unmanned surface vehicle "Edredon" in the camera optical sensors.
Sound Silencing Problem of Underwater Vehicles
Authors: Listewnik Karol
Published: March 2013

This paper describes some common problems associated with negative influence of UUV self noise on detection aspect in water environment. Some tasks of military applications require silent behavior of UUVs: Intelligence, Surveillance, and Reconnaissance (ISR), Rapid Environmental Assessment (REA), Mine Countermeasure (MCM) etc. Moreover, this paper review methods of underwater sound measurement and on the end as a summary presents results of an experiment from the water tank trials where were investigated three UUVs: one ROV and two biomimetic autonomous underwater vehicle.
Mechatronics Systems Supported by Vision Techniques
Authors: Kohut Piotr
Published: March 2013

In the paper an application of vision methods and algorithms in various domains that contribute to mechatronics is presented. Regarding mechatronics devices and machines as robots, a vision system employed for a testing station simulating an industrial assembly line is discussed. Some numerical aspects concerning image pre-processing, analysis and geometrical transformations commonly used in robotics were introduced. To accomplish an effective investigation, the developed methodology and algorithms were implemented and verified on an experimental setup composed of two industrial robots and automation devices cooperating with two various vision systems. In the case of underwater robots for tank inspection, image pre-processing and analysis algorithms for the robot's position estimation, an image scale calculation and wall crack detection were investigated. An active vibration control system is treated as a mechatronic device which contains mechanical parts, electronics and software. In this example, a visual servoing architecture based on image features for controlling an active vibration control system was examined. For an effective investigation and synthesis of visual servoing algorithms, a MATLAB/Simulink/dSPACE hardware–software environment was employed. A vision system was used to analyze vibration amplitude of the vibro-isolation mass of the active suspension system and to provide a feedback control signal. The connection of 3D vision techniques with modal analysis was shown. Within the confines of the project a methodology for amplitude of vibration measurement and a software tool for modal analysis realization based on visual data were developed. The 3D measurements and structure of the construction were obtained by application and development of passive 3-D vision techniques. From this area, ‘structure from motion’ techniques were developed. In the experimental research, a mechatronic test stand was designed and manufactured enabling automatic two-axis control of a camera. A frame structure was built, in which a guiding-rail system was mounted enabling straight-line motion of a camera. Additionally, a system realizing rotational motion of a camera was built in. To control the experiment stand, software was created enabling the combination of the hardware-software part of the stand with the software part of a vision system. A tool was developed for the purpose of modal analysis and estimation of the quantities characterizing dynamic properties of the structure based on vision signals. As a conclusion, the presented, implemented and tested vision methods in various hardware-software programming platforms are discussed
Influence of the Pouring Temperature on the Castability and Microstructure of Elektron 21 and QE22 Magnesium Casting Alloys
Authors: Dybowski Bartłomiej , Jarosz Robert , Kiełbus Andrzej
Published: March 2013

Magnesium alloys are widely used in aerospace and automotive industry due to their low density, good mechanical properties and good castability. The paper presents results of the castability tests and microstructural investigations on two unmodified magnesium casting alloys, Elektron 21 and QE22. Spirals for the castability test were poured from three temperatures: 755°C, 800°C and 835°C. Volume fraction of eutectic regions and grain size in both alloys were quantitatively evaluated. Castability increased with increasing pouring temperature. Quantity of eutectics and grain size did not show straight correlation with pouring temperature.
The Influence of Plastic Deformation on Structure of Highly Crosslinked UHMWPE Intended for Endoprosthesis Cups
Authors: Maszybrocka Joanna , Cybo Jerzy , Cwajna Jan , Barylski Adrian , Czaja Piotr
Published: March 2013

In this paper, an attempt has been made to determine the changes in the structure of UHMWPE under the influence of deformation, which can be the cause of the decrease of functional properties. It has been found that the degree of cross-linking slightly changes due to operational loads (deformation ef=0.15-0.6). The deformation leads, however, to the systematic lowering of the degree of crystallinity and an insignificant decrease of lamella width. Tests of wide- and small-angle X-ray scattering (WAXS, SAXS) prove that this is the result of operational deformation causing a rather weak texture of crystals and the fragmentation of some lamellae. Anisotropy of the lamellar structure also takes place, which changes 2D SAXS images into ellipses with a rapidly growing axial ratio with ef value.
Metrology and Morphology of γ’ and γ’’ Nanoparticles in Inconel 718 Measured by FIB-SEM Tomography
Authors: Kulawik Krzysztof , Dubiel Beata , Czyrska-Filemonowicz Aleksandra
Published: March 2013

Quantitative analysis of γ' and γ" phase nanoparticles in Inconel 718 was performed using FIB-SEM tomography. Three-dimensional visualisation showed that γ' particles are spherical, while γ" precipitates are disc-shaped. The dependence of the particle size of both phases on the heat treatment applied was detected. It was proven that the FIB-SEM tomography is a very precise method for metrology and morphology investigation of nanoparticles precipitated in Inconel 718 superalloy.
The Influence of Various Etchants on the Quantitative Analysis of Microstructure of Mg-Nd Alloy
Authors: Stopyra Michał , Kiełbus Andrzej
Published: March 2013

The paper presents the results of the influence of various etchants on the quantitative analysis of microstructure of Mg-Nd master alloy. The methodology of quantitative analysis of these alloys’ microstructure were also presented. Qualitative analysis were done using light and scanning electron microscopes, chemical composition was investigated using EDS method. Seven types of etchants were used. Having chosen suitable images, quantitative analysis were done using Met-Ilo program. Comparison of results showed that chosen etchants didn’t make the significant influence on the quantitative analysis results of the microstructure, despite visible dissimilarities.
Advanced Statistical Refinement of Surface Layer’s Discretization in the Case of Electro-Spark Deposited Carbide-Ceramic Coatings Modified by a Laser Beam
Authors: Pietraszek Jacek , Radek Norbert , Bartkowiak Konrad
Published: March 2013

Carbide coatings have numerous industrial applications due to their high abrasion, sliding and erosion resistance. The paper presents results of an advanced statistical analysis – involving auxiliary simulation methods like smooth bootstrapping and imputing of missing data – executed on surface layer profile of modified carbide-ceramic coatings. Source data were gathered in the previous research by Radek and Bartkowiak focused on microstructure analysis (SEM Joel JSM-5400), microhardness (Vickers method), roughness (FORM TALYSURF-120L) and adhesion (CSEM REVETEST)) tests. Anti-wear coating were first deposited on carbon steel C45 from WC-Co-Al2O3 electrodes in the process of the electro-spark alloying (ESA) by the EIL-8a apparatus. In the next step the coating were laser melted using impulse mode of Nd:YAG laser (BLS 720 model). Due to significant irregularity of collected data, the special methods of smoothing and imputing were involved based on Monte-Carlo methods. The collected data set was several times randomly divided into analytical and verification sub-sets and mentioned methods were applied. The results were used to calculate descriptive statistics like average values, variances, confidence intervals and smoothed histograms of probability distributions. The validity of the proposed approach was positively verified and it significantly improved quality of the results. The smoothing and imputing of data allow to avoid numerical artifacts that may arise during the classical statistical calculations on irregular data.
The Quantitative Assessment of the Fracture Profile of Magnesium Alloy QE22 Welded Joint
Authors: Adamiec Janusz
Published: March 2013

Magnesium alloys are a part of a group of lightweight and ultra-lightweight alloys, which are important in practical use in constructions. QE22 casting magnesium alloy containing silver, rare earth elements and zirconium is characterized by creep resistance up to the temperature of 200 °C, while during a short exposure it can resist up to the temperature of 250°C. Nowadays, QE22 magnesium alloy are used for casting into sand moulds. In castings of magnesium alloys defects or inconsistencies (such as casting misruns, porosities and cracks) often appear, particularly in huge dimensional castings. Such defects are repaired with the use of padding and welding. Welded joints must ensure suitable operational properties, mainly in terms of creep, so that the repaired casting can work under the same conditions as the correct cast. The basic source of information about the cause and cracking propagation is fracture after creep test. The quantitative fractography, in particular profilomety, allows to describe the fracture and basis on it conclude the causes of destruction. In this paper quantitative procedure for assessing the fracture profile of QE22 welded joints after creep test was worked out. Base on its analysis result, it was found that creep resistant of the QE22 joints is determined by eutectic areas, therefore they must be heat treated after welding joints.
The 3D Imaging and Metrology of CMSX-4 Superalloy Microstructure Using FIB-SEM Tomography Method
Authors: Kruk Adam , Dubiel Beata , Czyrska-Filemonowicz Aleksandra
Published: March 2013

STEM-EDX and FIB-SEM tomography studies have been carried out to visualize three-dimensional morphology of the γ’ precipitates in different zones of ex-service turbine blade made of CMSX-4 single crystal superalloy. The results allowed the three dimensional analysis of the changes in microstructure of blade as resulting of operating conditions. Tomographic reconstructions provided quantitative data about γ and γ’ phase shape, size and volume fraction. It was shown that FIB-SEM tomography technique is suitable for 3D reconstruction of the objects of 100 nm in size or even smaller and thus enables the accurate quantitative microstructural analysis of this superalloy.
Pneumatic Robot for Monitoring Hazardous Environments of Coal Mines
Authors: Kasprzyczak Leszek , Trenczek Stanisław , Cader Maciej
Published: March 2013

The GMRI robot is capable of inspecting hazardous zones of methane and/or coal dust explosion in hard coal mines. The robot enables remote measurements of the concentrations of methane, carbon monoxide, carbon dioxide, oxygen, temperature, and humidity. Cameras enable the robot to observe the state of the excavation. All electronic circuits of the robot, for measurements, control, transmission, and supply, are intrinsically safe. The transmission of data and control commands from/to the operators console are performed via an electric wire. Moreover, the wire enables to transmit intrinsically safe electric energy and is used to charge one of the accumulators. Thanks to that, the robot can operate in an isolated excavation for 3 months. An intrinsically safe pneumatic drive has been applied for setting wheels in motion. The non-commercial robot prototype was tested in a real excavation in an active hard coal mine. The technical solutions have been presented in the paper.
Polymer Fuel Cells in Underwater Platforms
Authors: Grzeczka Grzegorz
Published: March 2013

The analysis of the available fuel cells technologies indicates that Polymer Electrolyte Membrane Fuel Cells (PEMFCs) currently offer the highest attainable efficiency. This technology has been especially useful for underwater applications, since the moment it reached the greatest mass and volumetric power density among all available types of fuel cells (i.e. respectively more than 700 W/kg and 1100 W/dm3) [1,. The article presents the results of the preliminary research steps, aimed at establishing the genuine power supplying system of an underwater platform, to verify the applicability of this technology to specific underwater conditions.
Base Station for Monitoring of Unmanned Aerial Vehicle Flight
Authors: Słowik Maciej , Gosiewski Zdzisław
Published: March 2013

A configuration of universal base station designed to use mobile networks for long-range transmission of telemetry data is described in the paper. Types of cellular networks and modes of their operation are presented. Next, GPRS system is shown as a possible method of data transmission between UAV and Base Station. Communication modes of the station can be augmented by additional close-range communication system based on Xbee modules. The configuration and integration of test stand for telemetric signals monitoring are shown. Finally, the modes of possible operations based on the conditions of mobile networks are described.
Hybrid Electroactive Wings Morphing for Aeronautic Applications
Authors: Chinaud Maxime , Scheller Johannes , Rouchon Jean François , Duhayon Eric , Braza Marianna
Published: March 2013

As part of the RTRA funded EMMAV (Electroactive Morphing for Micro-Airvehicles) research program electroactive materials were studied as well as their applications as actuators for morphing wings. The aim of this research program is to study both the actuation with large displacements at low frequencies as well as low displacement, high frequency actuation. The large displacement actuation, which targets primarily the flight control, is achievable using Shape Memory Alloys (SMA) while high frequency; low displacement actuation can be achieved using piezoelectric actuators [. This high frequency actuation is especially interesting for improving the aeroelastic coupling effect inducing both noise and drag. This paper describes the construction of a prototype incorporating piezoelectric and SMA based actuation mechanisms. Furthermore, a cooling mechanism for SMAs is described aiming at improving the cycle time of the actuator. The developed prototype is to be evaluated during wind-tunnel experiments showing the influence of the actuation on the fluid.
Characteristics of an Experimental MSMA-Based Actuator
Authors: Flaga Stanisław , Oprzędkiewicz Iwona , Sapiński Bogdan
Published: March 2013

Magnetic Shape Memory Alloys (MSMA) constitute one of the newest groups of intelligent materials [. Although these materials have yet to find commercial applications, literature with information on the first pre-prototype actuators can already be found. The mechanism of operation of these actuators is based on the magnetic shape memory effect. During tests, the shifting of piston and current in the coil of the electromagnet were measured. Measurements were synchronized with set courses of this current coil of the actuator. The obtained results made it possible to make static characteristics for constant levels of current, and dynamic curves for constant values of frequency as well as to construct a mathematical model. In this work, the authors have described laboratory tests of an experimental actuator of this type.
Cleaning System for Automated Optical Inspection of Heads of Bearing Rollers
Authors: Zbrowski Andrzej
Published: March 2013

The paper presents problems connected with the preparation of technical objects, including bearing rollers, for the process of the in-process, on-line automatic optical inspection. The objective was to develop an industrial solution ensuring automatic removal of pollutants from the technological process, located on the controlled surface of the object examined. The developed method allows for effective removal of both liquid and solid pollutants from the surface of the roller originating from the technological process. The removal is conducted in such a way that the quality control of the tested object is possible on the basis of the digital image obtained automatically at the test stand. The control process is limited by the efficiency of the cleaning process. The critical parameter is the achievement of expected effectiveness. The basic assumption was to adjust the efficiency of the control process to the efficiency of the production line (3 items/s). The essence of the presented solution is cleaning of the heads of bearing rollers in an automated, non contact manner with total elimination of the handwork. Therefore, the method meets the requirements of the automated process of cleaning of bearing rollers' heads right before the process of automated optical inspection of an object.
Investigation of Oscillations of the Piezoelectric Actuator with Two-Directional Polarization
Authors: Lučinskis Raimundas , Mažeika Dalius , Bansevičius Ramutis
Published: March 2013

The recent trends in robotics and mechatronics necessitate for developing small-size multi-DOF motion systems. Piezoelectric actuators are one of the feasible solutions of this problem. An investigation of the contact point multicomponent oscillations of the beam type piezoelectric actuator with two-directional polarizations under different excitation regimes is presented in the paper. Polarization of the actuator has perpendicular directions on the first and second half of the actuator. Two-directional polarization of the actuator is used to achieve flexural oscillations of the actuator in two perpendicular planes. Superposition of longitudinal and flexural modes allows achieving oscillations of contact point in different planes. Electrodes of the actuator are divided into sections, and several excitation schemes are used to control a trajectory of the contact point movement. Numerical simulation and experimental study of piezoelectric actuator oscillations were performed. Elliptical motions of the contact point were obtained in different planes. Dependencies of contact point oscillation trajectories from excitation voltage phase and amplitude are determined at different excitation regimes.
Magnetic Thrust Bearing for the ORC High – Speed Microturbine
Authors: Kozanecki Zbigniew , Łagodziński Jakub
Published: March 2013

The paper is devoted to the FEM modeling of a magnetic thrust bearing for the small power, high-speed microturbine, working in the Organic Rankine Cycle. The microturbine is used to produce electricity in small dissipated power generation systems.
Robot Control System for Stereotactic Surgery
Authors: Sibielak Marek , Rączka Waldemar , Konieczny Jarosław , Moskała Marek , Krupa Mariusz
Published: March 2013

The article presents a prototype of a robot control system for stereotactic brain surgery. The development of neuroimaging, as well as the implementation of modern devices for neurosurgery, has undoubtedly contributed to significant progress in this field of medicine. Reaching a pathology located deep inside does not pose significant difficulty from the technical point of view; it is the selection of the access route that is the problem - to prevent the occurrence of permanent neurological deficits, such as severe paresis, vision disorders, speech or consciousness disorders. Obviously, knowledge of brain anatomy allows for adopting appropriate surgical tactics; however, some patients with a high-risk access route are not qualified for surgery. Even the hand of the most skilled operator does not guarantee precise removal of the tumour whilst bypassing important neural pathways, hence the necessity of introducing robots, which increase the level of surgical precision. A neural surgeon is able to perform very complicated surgical actions; however, human psychophysical limitations in neurosurgical procedures are becoming increasingly important, as surgeons are more and more frequently willing to perform operations with accuracy higher than 1 mm, but this is virtually impossible without any enhancement. Apart from the natural limitations of precision of the human hand, the surgeon's mental and physical condition deteriorates during a several-hour-long surgical procedure, thus lowering the surgeon's fitness and precision of movement. High concentration and a frequently unnatural position during the surgery cause additional tiredness. Therefore, numerous research centres and commercial companies are working on surgical robots. It seems that neurosurgery is particularly inclined for the introduction of robots enhancing the precision of a surgeon's work.
Model Predictive Control for Lateral Position of Endless Metal Belts
Authors: Grosswindhager Stefan , Schulmeister Klemens , Kozek Martin
Published: March 2013

Endless metal belts play an important role in advanced processing lines or belt machines for many production processes. In contrast to standard conveyor lines metal belts must be run over cylindrical return drums due to the high elastic modulus of the belts material and the usually high level of pre-stress. Since cylindrical return drums do not provide passive lateral guidance (self-centering) they have to be actively adjusted by swiveling drum axes. In this work a suitable control scheme is presented to guarantee a set lateral position at the return drums even in the presence of a lateral disturbance force. Since the lateral dynamics of the endless belt show strong coupling between all inputs and all outputs a multivariate control approach with inherent decoupling capabilities is needed. Moreover, a number of technological constraints must be fulfilled for all operating conditions such as limited swivel angles and the maximum allowable tensile stress in the belt. In this research work a constrained model predictive control (MPC) is therefore designed to overcome the aforementioned problems. The model is based on a description in the spatial domain (belt travel) which renders the model independent of operating speed. Using this model a multi-input multi-output (MIMO) MPC-scheme is derived also in state-space representation. Moreover, the control explicitly considers constraints on the control inputs and on the maximum allowable belt stress.
Monitoring and Diagnostics of the Rotating System with an Active Magnetic Bearing
Authors: Gizelska Małgorzata , Kozanecka Dorota , Kozanecki Zbigniew
Published: March 2013

In the paper, a concept and selected procedures of the specialized software using advanced information technology for the diagnostic system dedicated for systems of rotating machines with active magnetic bearings will be presented. It is used in the actual operation of the machine, enabling an increase of its reliability. The paper presents some selected results of control of the proper operation of the mechatronic rotating system, carried out in the automatic mode.
Novel Concepts and Criteria for Design Optimization of Controlled Mechanical Systems
Authors: Kiriazov Petko
Published: March 2013

Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active suspension, and other engineering structures with active vibration/shape control. CMS have to be considered as functionally directed compositions of mutually influencing subsystems: control, actuator, structural, and sensor subsystems. Such systems have highly complex dynamics and an advanced conceptual framework is needed that considers at the same time the problems of full dynamic modelling, optimal system design, accurate parameter identification, and optimal robust control. There are various design tasks for controlled mechanical systems (CMS), where continuously increasing demands for higher speed, better motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study their controllability and find efficient solutions for the control-related, design optimization problems. Our intention is to present novel concepts and criteria for design optimization of CMS with decentralized controllers at the lowest (joint) level. The first step is to find a dynamic model relating the control inputs and the controlled outputs which is suitable for both purposes: accurate parameter identification and robust control design. To do that, we can apply the so-called multibody system approach: the mechanical structure of CMS can be approximated by a composition of rigid bodies connected by joints, actuators, springs, and dampers. Then we find explicit necessary and sufficient conditions on the control transfer matrix that can guarantee robust controllability in the face of arbitrary, but bounded disturbances. Thus the design optimization process has to involve, besides the basic strength/load capacity criterion, additional design relations for optimal trade-off between the bounds of disturbances and the control force limits. The proposed approach enables decomposing the complex CMS design task into much simpler optimization problems for the CMS components: mechanical structure, actuators, sensors, and controllers. The new design concepts will be illustrated with several optimization examples of CMS concerning their shape, mass distribution, actuators' sizes and locations, and control functions.
Robust Optimal Control of MAV Based on Linear-Time Varying Decoupled Model Dynamics
Authors: Mystkowski Arkadiusz
Published: March 2013

This paper discusses a nonlinear robust control design procedure to micro air vehicle that uses the singular value (μ) and μ-synthesis technique. The optimal robust control law that combines a linear parameters varying (LPV) of UAV (unmanned aerial vehicle) are realized by using serial connection of the Kestrel autopilot and the Gumstix microprocessor. Thus, the robust control feedback loops, which handle the uncertainty of aerodynamics derivatives, are used to ensure robustness stability of the UAV local dynamics in longitudinal and lateral control directions.
Dynamic Characteristics of a Piezoelectric Transducer with Structural Damping
Authors: Płaczek Marek
Published: March 2013

Work presents a proposal of an analysis method of the piezoelectric transducer. The considered system is a longitudinally vibrating single PZT plate. The main aim of this work is to designate characteristics of the considered PZT plate. Using constitutive equations of piezoelectric materials and an equation of the plates motion a matrix of characteristics of the system was obtained. Relations between mechanical and electrical parameters (forces, displacements, electric current and voltage) that describe behaviour of the system are included in the matrix of characteristics. A dynamic flexibility relation between the plates deformation and a force applied to the system is considered. A structural damping of the plates material was being taken into consideration and its influence on the plates dynamic flexibility is analysed. This work is an introduction to a task of analysis of complex systems. In future work the developed model and proposed mathematical algorithm will be used to analyse piezoelectric stacks. Non-classical methods will be used. It is a part of research works of Gliwice research centre related with an analysis and synthesis of mechanical and mechatronic systems [4-7,9,10,16-18]. Passive and active mechanical and mechatronic systems with piezoelectric transducers were analysed [1-3]. Works were also supported by computer-aided methods [8]. Both classical and non-classical methods were being considered. The discussed subject is important due to increasing number of applications of both simple and reverse piezoelectric phenomena in various modern technical devices.
Behavior Based Complete Coverage Task of Unknown Area by an Autonomous Mobile Robot SCORPION with Static Obstacles in Environment
Authors: Dąbkowski Mariusz , Skrzek Paweł , Redlarski Grzegorz
Published: March 2013

In the paper the behavior based control system of an autonomous mobile robot SCORPION is presented to execute the one of the most difficult navigation task, which is the complete coverage task of unknown area with static obstacles in the environment. The main principle assumed to design control system was that the robot should cover all area only once, if it possible, to optimize the length of path and energy consumption. All commercial robots like Roomba, Trilobite or IVO move using structured templates combined with random movement. Therefore the path of coverage is not optimal directions of movement are often chosen randomly, so robot covers the same area many times wasting time and energy. In paper the five main developed templates of movement were described to fulfill main task in ordered manner using primarily the way of the ox template of coverage [1, 2, 5, 1. The behavioral control system is implemented in a computer application written in Python [5]. In the paper the test methodology of the developed system on real mobile robot ERSP SCORPION equipped with IR sensors is presented. Graphical and quantitative results of tests of accomplishment of complete coverage task are given for 6 different configurations of obstacles in the robots environment. Conclusions are presented and discussed [5]. Ways to improve the quality indicators [1, of the task of complete coverage of a unknown area are also showed.
Formation of anthropogenic secondary organic aerosol (SOA) and its influence on biogenic SOA properties
Authors: Emanuelsson E. U. , Hallquist M. , Kristensen K. , Glasius M. , Bohn B. , Fuchs H. , Kammer B. , Kiendler-Scharr A. , Nehr S. , Rubach F. , Tillmann R. , Wahner A. , Wu H.-C. , Mentel Th. F.
Published: March 2013

Abstract. Secondary organic aerosol (SOA) formation from mixed anthropogenic and biogenic precursors has been studied exposing reaction mixtures to natural sunlight in the SAPHIR chamber in Jülich, Germany. In this study aromatic compounds served as examples of anthropogenic volatile organic compound (VOC) and a mixture of α-pinene and limonene as an example for biogenic VOC. Several experiments with exclusively aromatic precursors were performed to establish a relationship between yield and organic aerosol mass loading for the atmospheric relevant range of aerosol loads of 0.01 to 10 μg m−3. The yields (0.5 to 9%) were comparable to previous data and further used for the detailed evaluation of the mixed biogenic and anthropogenic experiments. For the mixed experiments a number of different oxidation schemes were addressed. The reactivity, the sequence of addition, and the amount of the precursors influenced the SOA properties. Monoterpene oxidation products, including carboxylic acids and dimer esters were identified in the aged aerosol at levels comparable to ambient air. OH radicals were measured by Laser Induced Fluorescence, which allowed for establishing relations of aerosol properties and composition to the experimental OH dose. Furthermore, the OH measurements in combination with the derived yields for aromatic SOA enabled application of a simplified model to calculate the chemical turnover of the aromatic precursor and corresponding anthropogenic contribution to the mixed aerosol. The estimated anthropogenic contributions were ranging from small (≈8%) up to significant fraction (>50%) providing a suitable range to study the effect of aerosol composition on the aerosol volatility (volume fraction remaining (VFR) at 343 K: 0.86–0.94). The aromatic aerosol had higher oxygen to carbon ratio O/C and was less volatile than the biogenic fraction. However, in order to produce significant amount of aromatic SOA the reaction mixtures needed a higher OH dose that also increased O/C and provided a less volatile aerosol. The SOA yields, O/C, and f44 (the mass fraction of CO2+ ions in the mass spectra which can be considered as a measure of carboxylic groups) in the mixed photo-chemical experiments could be described as linear combinations of the corresponding properties of the pure systems. For VFR there was in addition an enhancement effect, making the mixed aerosol significantly less volatile than what could be predicted from the pure systems. A strong positive correlation was found between changes in volatility and O/C with the exception during dark hours where the SOA volatility decreased while O/C did not change significantly. Thus, this change in volatility under dark conditions as well as the anthropogenic enhancement is due to chemical or morphological changes not affecting O/C.
Impact of the Megalake Chad on climate and vegetation during the late Pliocene and the mid-Holocene
Authors: Contoux C. , Jost A. , Ramstein G. , Sepulchre P. , Krinner G. , Schuster M.
Published: March 2013

Abstract. Given the growing evidence for megalakes in the geological record, assessing their impact on climate and vegetation is important for the validation of paleoclimate simulations and therefore the accuracy of model/data comparison in lacustrine environments. Megalake Chad (MLC) occurrences are documented for the mid-Holocene but also for the Mio-Pliocene (Schuster et al., 2009). The surface covered by water would have reached up to ~350 000 km2 (Ghienne et al., 2002; Schuster et al., 2005; Leblanc et al., 2006) making it an important evaporation source, possibly modifying the climate and vegetation in the Chad basin. We investigated the impact of such a giant continental water area in two different climatic backgrounds within the Paleoclimate Model Intercomparison Project phase 3 (PMIP3): the late Pliocene (3.3 to 3 Ma, i.e. the mid-Piacenzian warm period) and the mid-Holocene (6 kyr BP). In all simulations including a MLC, precipitation is drastically reduced above the lake surface because deep convection is inhibited by colder air above the lake surface. Meanwhile, convective activity is enhanced around the MLC, because of the wind increase generated by the flat surface of the megalake, transporting colder and moister air towards the eastern shore of the lake. Effect of the MLC on precipitation and temperature is not sufficient to widely impact vegetation patterns. Nevertheless, tropical savanna is present in the Chad Basin in all climatic configurations, even without the MLC presence, showing that the climate itself is the driver of favourable environments for sustainable hominid habitats.
Modeling atmospheric ammonia and ammonium using a stochastic Lagrangian air quality model (STILT-Chem v0.7)
Authors: Wen D. , Lin J. C. , Zhang L. , Vet R. , Moran M. D.
Published: March 2013

Abstract. A new chemistry module that simulates atmospheric ammonia (NH3) and ammonium (NH+4) was incorporated into a backward-in-time stochastic Lagrangian air quality model (STILT-Chem) that was originally developed to simulate the concentrations of a variety of gas-phase species at receptors. STILT-Chem simulates the transport of air parcels backward in time using ensembles of fictitious particles with stochastic motions, while accounting for emissions, deposition and chemical transformation forward in time along trajectories identified by the backward-in-time simulations. The incorporation of the new chemistry module allows the model to simulate not only gaseous species, but also multi-phase species involving NH3 and NH+4. The model was applied to simulate concentrations of NH3 and particulate NH+4 at six sites in the Canadian province of Ontario for a six-month period in 2006. The model-predicted concentrations of NH3 and particulate NH+4 were compared with observations, which show broad agreement between simulated concentrations and observations. Since the model is based on back trajectories, the influence of each major process such as emission, deposition and chemical conversion on the concentration of a modeled species at a receptor can be determined for every upstream location at each time step. This makes it possible to quantitatively investigate the upstream processes affecting receptor concentrations. The modeled results suggest that the concentrations of NH3 at those sites were significantly and frequently affected by Ohio, Iowa, Minnesota, Michigan, Wisconsin, southwestern Ontario and nearby areas. NH3 is mainly contributed by emission sources whereas particulate NH+4 is mainly contributed by the gas-to-aerosol chemical conversion of NH3. Dry deposition is the largest removal process for both NH3 and particulate NH+4. This study revealed the contrast between agricultural versus forest sites. Not only were emissions of NH3 higher, but removal mechanisms (especially chemical loss for NH3 and dry deposition for NH+4) were less efficient for agricultural sites. This combination explains the significantly higher concentrations of NH3 and particulate NH+4 observed at agricultural sites.