bluuebunny/crossref_metadata_2025 huggingface dataset:
Grain Evolution Character of Discal Parts by Roll Forming
Authors: Jin Quan Lin
Published: March 2013

A study on grain evolution character of discal parts roll forming was carried out by means of experiment and numerical simulation. The discal part material is aluminum alloy 6061 and titanium alloy TC4. The roll forming temperature is 480-500 and 930-1020 for aluminum alloy 6061 and titanium alloy TC4, respectively. A digital double-sided roll forming machine was used for roll forming experiment of discal parts. The high frequency induction heating was used for disk heating, where the deformation zone is in the state of constant temperature. A numerical simulation of roll forming of the 6061 aluminum alloy disk was carried out. The simulated results include macroscopic deformation and various grain size evolution variables. The dynamic recrystallization, the dynamic and static grain growth were considered in the numerical simulation. The experimental and simulated results showed that there may appear not only the grain refinement due to dynamic recrystallization but also dynamic and static grain growth. It is different that from discal parts integrally forging there are the largest deformation, the highest strain rate and the best recrystallization and grain refinement in the zones contacted with the roll tools. In the zones far from the rollers, the strain rate is very low and average grain size increases until once again contact to the rollers and start new grain refinement.
Tungsten-Copper Composite Fabricated by Hot-Shock Consolidation
Authors: Zhou Qiang , Chen Peng Wan , Ma Dan Zhu
Published: March 2013

High-temperature shock consolidation and under-water shock wave are two effective methods to eliminate cracks generated when shock wave propagating the powder bed. In this work, a novel assembly consists of a chemical furnace and a water column was used to fabricate tungsten-copper composites. The heat released from the reaction of a SHS reaction mixture was used as chemical furnace to preheat the precursor powder. The water column as well as the explosive attached was detached from the furnace by a solenoid valve fixed on the slide guide. So the explosive and water column was kept cooling during the preheating process. The W-Cu powders with the grain size of 2μm were first blended with mass ratio of 9:1 by mechanically alloying in a planetary ball mill. Prior to application of shock wave, the elemental powders were preheated at different temperatures, i.e. the highest temperature up to 1000°C. The intensity of the shock wave loading was under 10GPa. The consolidated specimens were then characterized by microstructure analysis and micro-hardness testing. The different micromechanical behaviors of W and Cu phase in the consolidated sample were studied by using in situ high-energy X-ray diffraction technique. The result showed that a fine-grained 90W/10Cu composite with no cracks could be compacted to a density of 16.44g/cm3 by hot-shock consolidation at a preheating temperature of 970°C.
Research on Preparation Technology of High Quality Diamond Film
Authors: Zhou Chang Geng , Qiu Rui , Ke Jian Lin , Liu Cai Lin , Wang Bing
Published: March 2013

The diamond films deposition experiment is carried out with MPCVD system. Some technology problems are discussed respectively, such as the substrate pretreatment, gases source compositions and deposition temperature. XRD pictures with different peaks illustrated that diamond film has good crystal orientation. A density of film crystal is observed and a thickness uniformity in detected by Scanning Electron Microscopy (SEM). The pureness of the diamond film was measured by Raman spectroscopy. The parameter coincidence rate is 90% based on the 10 prepared samples
Size Dependent Mechanical Properties of Graphene Nanoribbons: Molecular Dynamics Simulation
Authors: Sun Yun Jin , Ma Fei , Xu K.W.
Published: March 2013

Strain engineering is an effective method to tune the band gap and electronic transport properties of graphene nanoribbons (GNRs). However, strain/stress field may promote the system deviating from the equilibrium state, and the mechanical stability will become one of the key issues for reliable services of relevant devices. In this paper, the size-dependent mechanical properties of GNRs under tensile loading were studied by Molecular Dynamics (MD) simulations. The results indicate that the yield stress of both zigzag and armchair GNRs decreases with the ribbon length changing from 240 Å to 30 Å. However, the ductility of armchair GNRs was significantly improved. Radial Distribution Function (RDF) was employed to analyze the evolution of atomic configurations. It showed that lattice shearing is the main mechanism for the ductility of armchair GNRs.
Generating 2D Non-Equiaxed Initial Microstructure for Monte Carlo Simulation Using Modified Voronoi Model
Authors: Liu Yun Teng , Zhou Ji Xue , Tian Chang Wen , Zhan Cheng Wei , Li Wei Hong , Guan Xiao Jun
Published: March 2013

A modified Voronoi model is established based on the Richards method to generate 2D non-equiaxed initial microstructure for Monte Carlo simulation. Microstructures produced by the ordinary Voronoi model are isotropic and cannot reflect the effects of the deformed grain shape on the annealing process. The modified Voronoi model based on ellipse set can be used to construct the deformed microstructure. The initial microstructure reflects the mean strain and the grain size distribution follows lognormal distribution.
Effects of La2O3 on Microstructure and Properties of Laser Clad Fe-Based Amorphous Composite Coatings
Authors: Lu Qing Long , Wang Yan Fang , Xiao Li Jun , Li Xin Mian , Yu Zhi Guo , Shi Zhi Qiang
Published: March 2013

The Fe-Cr-Si-P amorphous powder with various La2O3contents was cladded on 304L substrates by laser technology. The effects of La2O3contents on microstructure and properties of the coatings were investigated. The results showed that the coating mainly consisted of amorphous, Fe3P and Fe2Si phases. A small amount of La2O3addition could inhibit the epitaxial growth, and refine the dendrite crystals. When the content of La2O3was 0.1%, the amorphous content of the coating was up to about 55%, and the maximum microhardness was about 900HV0.2.
Effects of SPS Pulse Current on Interface of Al90Mn9Ce1/ZrO2 Micro-Cellular Structure Composites
Authors: Zan Zhao , Wang Ming Gang , Zhao Zhan Kui
Published: March 2013

Metal/ceramic composite materials with micro-cellular structure which is Al90Mn9Ce1 micron powders coated by 10 wt% ZrO2 nanosized powder is prepared by spark plasma sintering. Effects of the SPS pulse current on the sintering behavior and the composite interface structure is investigated via SEM, XRD, TEM and EDS. The experimental results show that the pulse current is the key factor to the formation of micro-cellular structure. When the Al90Mn9Ce1/ZrO2 composites are sintered by a large pulse current, the hot focus on ZrO2 nanopowder among Al90Mn9Ce1 alloy particles as well as Al90Mn9Ce1 alloy particle surface, because of the effect of spark plasma and the concentration of the skin effect in short-term. Dividing temperature field on the interface of micro-cellular structure is benefit for the local high-temperature sintering of the ceramic cell walls layer, and also for the diffusion and interfacial bonding between Al90Mn9Ce1 alloy cell body and the ZrO2 nanosintered cell wall, so as to achieve good sintering.
Numerical Simulation of Electro-Slag Remelting Process Solidification Structure of Cr-Co-Mo-Ni Bearing Steel
Authors: Bai Li Guo , Yang Mao Sheng , Li Jing She
Published: March 2013

The solidification microstructure and crystallization of Cr-Co-Mo-Ni bearing steel were simulated in solidification process based on CAFE methods in the electro-slag remelting process. The optimization of the intensity of cooling and molten pool temperature was simulated for Cr-Co-Mo-Ni bearing steel. The result shows that raising the cooling intensity to 7.5 m3/h and reducing the superheat temperature to 1600 can increase the grain nucleation number about 13.83%, and reduce the average columnar grain radius about 10.61%, to have a very good effect on refining the grains and get dense uniform solidification, which improve the homogeneity of the solidification structure, and reduce the performance differences of the materials.
Synthesis of MAX Phase (Cr,V)2AlC Thin Films
Authors: Sun Z.M. , Sonoda Tsutomu , Hashimoto Hitoshi , Matsumoto Akihiro
Published: March 2013

Multiple target magnetron sputtering technique was employed for the deposition of (Cr,V)2AlC thin films, on the substrate of Si wafer at temperatures ranging from ambient to 840 K. The chemical composition and crystal structure of the deposited thin films were analyzed, surfaces as well the cross sections observed. The experimental results demonstrated that the temperature of the substrate does not affect the chemical composition of the deposited thin films. Deposition at room temperature or moderate elevated temperatures was found to result in amorphous films, whereas crystalline MAX phase thin films were obtained at high temperature. The transition of the substrate temperature was found to be around 743 K. The thin films deposited at temperatures below the transition showed the featureless flat surfaces. At high substrate temperatures, crystalline MAX thin films were formed. When deposited at temperatures near the transition, amorphous/nanocrystalline double layer thin films were deposited.
Application of Magnetic Field Method for Measuring Lubricant Viscosity
Authors: Sriratana Witsarut , Murayama Riichi
Published: March 2013

This study presents an application of Hall Effect sensor to assess the viscosity of industrial lubricant by using reference metal particles with the dimension ranging from 1 µm to 100 µm and the mass ranging from 0.1 g to 1 g as the essential modules of the developed system. Hall Effect sensor is a small electronic component which is easy for installing, analyzing, and processing due to electrical output generated. Moreover, the cost of this developed method is lower than other means of viscosity tests. At present, there are several studies on viscosity and quality tests of industrial lubricants such as Ultrasonic measurement of viscosity of liquids [1], Photoacoustic measurement of liquid viscosity [2], Measurement of magnetic viscosity in NdFeB [3], A viscosity and density meter with a magnetically suspended rotor [4], Capacitive sensor [5], IR-Absorption [6], and Optical fiber sensing [7]. In this study, the measurement methodology was considered only the lubricant viscosity at the temperature of 26 °C and then compared the results to the viscosity classification which is the reference of lubricant characteristic. Moreover, the lubricant types namely SAE 15W-40, SAE 20W-50 and ISO VG 100 were selected as the case studies.
Influence of Intermittent Air Introduction on Formation of Zn Films by Mechanical Coating Technique
Authors: Hao Liang , Lu Yun , Sato Hiromasa , Asanuma Hiroshi , Pan Fu Sheng
Published: March 2013

The influence of intermittent air introduction on the formation of Zn films during mechanical coating process was investigated. A series of contrast experiments were carried out. The XRD and EDS results showed that Zn particles were slightly oxidized. The SEM images indicated that disk-like zinc oxide (ZnO) nanocrystals were formed. The formation of disk-like ZnO made the morphology of Zn films more uneven and irregular. On the other hand, it increased the adhesion strength of Zn films to Al2O3 balls and hence the exfoliation of Zn films was not found.
The Effect of H3BO3 Microaddition on Microstructure of Ni/MgO Sintered Compact by Co-Precipitation Method
Authors: Zhou Ning Ning , Ju Dong Ying , Ding Wan Yu
Published: March 2013

In the present work, Ni/MgO powder was prepared by co-precipitation in which CO restore NiO to elemental subtance Ni due to C2O42- was decompose to CO and CO2 at 700°C. As the process of the second sintering, H3BO3 was added into the sintered powder of 700°C and was grinded. Then the powder of H3BO3 added was sintered at 800°C，so that the powder was refined, obviously. Thermogravimetric analysis (TGA) and differential thermal analysis(DTA) was carried out in CO2 flow at 10°C/min. X-ray diffraction (XRD) was carried out on a X-ray diffractometer operated at 20KV and 40mA. The microstructures and morphologies were studied by EPMA and XPS.
Study on the Application of Magnetic Nanoparticles as Drug Delivery Particles on the Atopic Dermatitis
Authors: An Gang , Ma Ping , Ju Dong Ying , Kumazawa Takashi
Published: March 2013

It is well known that the advances in the biomedicinal applications of magnetite nanoparticles were studied recently. As a drug delivery tools, it only affects on the target region of illness. We investigated the application of magnetic nanoparticles as drug delivery tools by the mice model of atopic dermatitis. The results involve that after magnetic nanoparticles are applied to the skin, the condition of atopic dermatitis becomes much better than the former one of atopic mice model. It only affects on the illness region and healthy regions almost have no influence. It is suitable for the medical treatment technique usage on the atopic dermatitis.
Effect of Mean Stress on Fatigue Strength of Spheroidal Graphite Cast Iron
Authors: Shinohara Norio , Hattori Nobusuke , Khan M.T.I.
Published: March 2013

Mechanical properties, especially fatigue strength, of ferritic spheroidal graphite cast iron might depend not only on the graphite size but also on the ferrite grain size, little systematic research has been made on these factors. To clarify the influences of these structural factors as well as loading condition, fatigue tests have been carried out on ferritic spheroidal graphite cast iron with different sizes of graphite nodules and ferrite grains, under the axial loading with mean stress from -70MPa to 240MPa. The results obtained in this study are summarized as follows: (1) The fatigue limits are decreased with increasing graphite nodule and matrix grain sizes. (2) The fatigue limit decreases with increasing tensile mean stress. The fatigue limit at an arbitrary mean stress has been estimated by the modified Goodman diagram as well. (3) The parameter α is evaluated from the experimental results relating to the stress ratio R, for the mean stress acting on the tensile side and on the compressive side separately. For the case of R0, the value of α is 0.324. The result has been applied to the fatigue limit evaluation equation of Y.Murakami et al, the fatigue limit ratio falls within the range of about ±10%.
Preparation of Paver Bricks Having both Water Retainability and Frost Resistance by Designing Macro Porous Structure
Authors: Sakamoto Naotaka , Oyakawa Yumeko , Tanaka Hiroshi , Nakano Tatsuhiro
Published: March 2013

We investigated to add some high functionality to the brick by controlling the porous structure of the brick. It was succeeded in this study that a great many minute continuous pores which lead to capillary action were introduced inside of bricks in order to bring about “UCHIMIZU effect” for suppressing urban heat island phenomenon. But, as for the high water retainable pavement material like that brick, it is broken by water freezing in winter, and from this reason any pavement material with “UCHIMIZU effect” are not readily spread in through the all over Japan. Then, preparation of the brick which had both water retainability and frost resistance was tried by introducing much space into the brick inside to be able to permit the solidification expansion of water, and examined influence on properties of the brick by the quantity of porosity. From results, it was suggested that water retainability and frost resistance were able to be given to the brick at the same time by using the cavity formation materials.
Effect of Minor Addition Ta on the Thermal Stability and Corrosion Resistance of Ti-Zr-Cu-Pd Bulk Metallic Glasses
Authors: Qin Feng Xiang , Xie Guo Qiang , Zhu Sheng Li , Dan Zhen Hua
Published: March 2013

In this research, the effect of Ta addition on the formation, thermal stability and corrosion behavior of Ti-Zr-Cu-Pd bulk metallic glasses were investigated. The results revealed with minor addition of Ta, higher corrosion resistance and compressive strength as well as large plastic deformation were achieved. Minor addition Ta is effective for the formation of more protectively passive film during the process of anodic polarization. In addition, proper volume fraction nanoparticle with small size is responsible for the large plastic deformation of the as-cast Ti-based bulk metallic glasses with 1% Ta addition.
Formation of Nanocrystalline Si by Au-Catalyzed CH3SiH3 Pulse Jet CVD
Authors: Abe Toshiaki , Anan Shouhei , Watanabe Fumiya , Takahashi Ryoji , Ikoma Yoshifumi
Published: March 2013

Au-catalyzed growth of nanocrystalline Si by pulse jet chemical vapor deposition has been investigated. Au thin film was first deposited on thermally oxidized Si(100), then CH3SiH3 pulse jets were irradiated onto the Au/SiO2/Si(100) surface. The irradiation of the CH3SiH3 jets at 1150 °C resulted in circular patterns with a diameter of ~40 µm on the sample surfaces. In the center of the circular patterns, agglomerations of Au were observed. It was found that the oxide layer was etched and that nanocrystalline Si with diameters ~500 nm was formed in the circular patterns. These results indicate that the nanocrystalline Si was grown by the VLS process in which Si atoms were supplied from the oxide layer, Si substrate, and CH3SiH3 molecules.
Photo-Electrochemical Properties of Titanium Dioxide Thin Films Prepared by Reactive RF Sputtering Method
Authors: Arita Makoto , Tabata Yu , Sakamoto Hiroki , Guo Qi Xin
Published: March 2013

The photo-electrochemical properties of photocatalytic titanium dioxide thin films obtained by reactive RF magnetron sputtering were investigated. The pressure during the sputtering deposition affected the photocatarytic activity and photo-induced hydrophilicity, and at 2 Pa the highest activities were observed. The photocurrent under ultraviolet light illumination corresponded to the photo-induced activities of the films. It is suggested that the band bending near the surface is one of the most crucial factors determines the activities of photo-induced behavior of the titanium dioxide thin films.
Nanopore Formation on SOI(100) by CH3SiH3 Pulse Jet CVD: SiC Growth Temperature Dependence
Authors: Ikoma Yoshifumi , Nishino Yuta , Anan Shouhei , Abe Toshiaki , Sakita Hirofumi
Published: March 2013

We investigated the formation of nanopores on top Si layers of silicon on insulator substrates by CH3SiH3pulse jet chemical vapor deposition. Nanopores were obtained by chemical etching of the buried oxide layer below the pits which were introduced during the SiC growth. The high nanopore density was obtained when the SiC growth temperature was set at 925 °C. The nanopore density gradually decreased with increasing the temperature at higher SiC growth temperature. The pore size increased with increasing the SiC growth temperature. These results suggest that pore density and size strongly depend on the SiC growth temperature.
Structure and Electrochemical Properties of DLC/SiC Films on the Surface of Magnesium Alloy by Plasma Immersion Ion Deposition
Authors: Guo Yuan Yuan , Zhao Hong Yang , Ju Dong Ying , Hase Alan , Wei Rong Hua
Published: March 2013

DLC/SiC films (SiC as a transition layer) were prepared on the surface of magnesium alloy (AZ31) using a plasma immersion ion deposition (PIID) process. A dense and smooth DLC film can be observed by SEM. The surface hardness can be improved to 11.45GPa by deposition of the DLC film. Electrochemical tests show that the corrosion potential of AZ31 with DLC film is increased from -1.7V to -0.6V, which indicates that the DLC film improves the corrosion resistance of Mg alloy.
The Effect of Working Pressure on the Composition and Optical Properties of TiO2 Films Bombarded by N Ion Beams
Authors: Yao Ting Ting , Liu Hong Lin , Ding Wan Yu , Ju Dong Ying , Chai Wei Ping
Published: March 2013

N-doped TiO2 films were prepared by using N ion beams to bombard TiO2 films surface. By controlling the metal ultrahigh vacuum gat valve, only the N ion beams working pressure was adjusted from 0.1 to 0.9 Pa, with the step size of 0.2 Pa. The composition, chemical bond structure, and optical properties of N-doped TiO2 films were investigated. The result indicated that with increasing the ion source working pressure, more N ions were generated and bombarded with the surface TiO2 films, which could result in more N ions were doped into the films. So with increasing the ion source working pressure from 0.1 to 0.9 Pa, the N/Ti and O/Ti atom ratio increased and decreased monotonously from 0.37 to 0.49 and 1.49 to 0.61, respectively. Meanwhile, because of more N doped into films, the mean absorbency of N doped TiO2 films in the visible range also increased monotonously from 4.8% to 45.8%.
Effect of Withdrawal Rate on Defects of Upgraded Metallurgical Grade (UMG)-Silicon Prepared by Vacuum Directional Solidification
Authors: Ma Wen Hui , Jiang Yong , Zhou Yang , Wei Kui Xian , Yang Bin , Dai Yong Nian , Morita Kazuki
Published: March 2013

The structural defects including dislocations and grain boundaries (GBs) in upgraded metallurgical grade silicon (UMG-Si) prepared by vacuum directional solidification were investigated. The results demonstrated that higher withdrawal rates increased the dislocation density. The state of melt growth changed from quasi-equilibrium to non-equilibrium, and the GB type was also highly related to the withdrawal rate, especially for ∑3 boundary. The change of total interfacial energy and increase of carbon concentration may be a possible driving mechanism for this phenomenon.
Roll-Gap Control System of Twin Roll Strip Caster Based on Feed Forward-Feedback
Authors: Zhang Wen Yu , Ju Dong Ying , Yao Yao , Zhao Hong Yang , Hu Xiao Dong , Teng Wei
Published: March 2013

In this paper, the established control system and its control algorism of a new twin roll strip caster developed by authors is presented. It is illustrated the roll-gap control strategy of the twin roll strip caster based on a feed forward-feedback system. From the experimental results, the susceptibility of control convergence time, stable and accurate are shown on a higher level than traditional control strategy.
In Situ Synthesis of Alumina Matrix Composites by Spark Plasma Sintering
Authors: Chen Zhong Chun , Nugroho Sri , Kawasaki Akira
Published: March 2013

Al2O3 matrix composites reinforced with Ba-b-Al2O3 phase were synthesized through reactive sintering using Al2O3 and BaCO3 as starting powders. Dense Al2O3/Ba-b-Al2O3 composites can be obtained by spark plasma sintering from Al2O3/BaO•Al2O3 powder, which was prepared by calcining Al2O3/BaCO3 powder mixture. The Ba-b-Al2O3 reinforcing phase exhibited an elongated morphology due to preferred diffusion of Ba cations. The existence of Ba-b-Al2O3 phase as well as low sintering temperature and short holding time during reactive sintering inhibit grain growth and thus result in small grain sizes of the Al2O3 matrix.
Investigating the Effect of Shape Factor, Slurry Layers and Pouring Temperature in Precision Investment Casting
Authors: Singh Rupinder , Singh Jagdeep
Published: March 2013

This paper aimed to investigate the effect of shape factor, slurry layers and pouring temperature in precision investment casting. Three controllable factors of the precision investment casting process (namely: shape factor, slurry layers (mold thickness) and pouring temperature) were studied at three levels each by Taguchis parametric approach and single-response optimization was conducted to identify the main factors controlling surface hardness, dimensional accuracy (Δd) and surface roughness (Ra). Castings were produced using aluminum (Al), mild steel (M.S.) and stainless steel (S.S) at recommended parameters through ceramic shell precision investment casting process. The micro structure analysis has been used to study the surface morphology. Analysis shows that for surface hardness, contribution of shape factor, slurry layers and pouring temperature is 0.07%, 0.70% and 99% respectively. As regards to surface roughness, contribution of shape factor, slurry layers and pouring temperature is 1.14%, 16.80% and 81.90% respectively. Further for Δd contribution of shape factor, slurry layers and pouring temperature is 1.53%, 22.47% and 72.88% respectively. Confirmation experiments were conducted at an optimal condition showed that the surface hardness, Δd and Ra of the precision investment casting were improved significantly.
Ferroelectric Properties of Strontium Bismuth Titanate (SrBi4Ti4O15) Synthesized Using Solution Combustion Technique
Authors: Shrivastava Saransh , Subohi Oroosa , Malik M.M.
Published: March 2013

The ferroelectric properties of layer-structured Strontium Bismuth Titanate (SBT) have been investigated in this study. SBT was prepared using solution combustion technique with glycine as a fuel. Single-phase formation of the layer-structured compound of SBT with orthorhombic structure was achieved after calcinations at 800 °C, and was confirmed by x-ray diffraction studies. Scanning electron micrograph shows that the grains exhibit a plate like morphology and possesses ne particle size. The as prepared sample exhibits ferroelectric properties with remnant polarization of 2Pr = 1.84 μC/cm2at coercive field 2Ec= 2.61 kV/cm and displays low dielectric loss. Its ferroelectric transition temperature (Tc) is found to be 450 °C.
Course Control of Unmanned Surface Vehicle
Authors: Szymak Piotr
Published: March 2013

The paper considers the problems of controlling a course of an Unmanned Surface Vehicle USV. To select proper course controller, following three methods were tested: PID, slide and fuzzy control. Moreover, to counteract sea current two methods were presented and compared by means of numerical research. In the introduction, the USV called edredon is presented. In the next section, principles of operation of the tested controllers are described. Then, the methods for sea current counteracting are inserted. In the end, the results of numerical research and conclusions from carried out comparisons are presented.
Trajectory-Tracking Control of Underwater Vehicles
Authors: Zak Andrzej
Published: March 2013

The main aim of paper is to introduce the results of research concentrated on controlling remotely operated underwater vehicle which task is trajectory tracking with high accuracy. Firstly the problem of trajectory tracking and its formal and mathematical description were introduced. Next the proposed fuzzy autopilot which assure high precision of trajectory tracking by underwater vehicle was presented. At the end the example results of research on trajectory tracking in environment without and with disturbance were presented. The paper is finished by summary which include conclusions derive from results of research.
Automated Guided Vehicle System for Work-in-Process Movement
Authors: Zajac Jerzy , Chwajoł Grzegorz , Wiek Tomasz , Krupa Krzysztof , Małopolski Waldemar , Słota Adam
Published: March 2013

The paper presents an automated guided vehicle transportation subsystem used for work-in-process movement, built at the Production Engineering Institute of Cracow University of Technology. It describes design and operational parameters of built vehicles as well as the principles of integration of AGV control subsystem with the AIM multi-agent manufacturing control system. Furthermore, results of the verification of applied path-finding, anti-collision and anti-deadlock algorithms are included.
The Fluctuational Model of Small Floating Objects Identification by Means of Passive Radar Reflectors
Authors: Lisowski Józef , Szklarski Andrzej
Published: March 2013

The paper presents the issues related to the probability of surface objects detection. The classical fluctuation models and the new fluctuation model for small floating objects with 10 m2 radar cross section surface are described. The possibilities of detection of examined passive radar reflectors by the radars on board merchant vessels were determined. Probability of detection of passive radar reflectors calculated using the classical fluctuation models was compared with the results obtained using the proposed new fluctuation model.
Stereological Characterization of TiC Carbides in Bottom Skull after Melting of Ti-6Al-4V-0,5C Alloy in Vacuum Induction Furnace
Authors: Szkliniarz Agnieszka , Jarczyk Georg
Published: March 2013

This paper presents the microstructural characteristics of skull formed during melting of Ti-6Al-4V alloy with 0.5 wt% content of carbon in vacuum induction furnace using water-cooled copper crucible. The microstructure of ingot obtained as a result of skull melting is comprised of TiC carbides evenly distributed in the matrix, which consists of lamellar precipitations of α and β phases. The depth of carbon penetration towards the bottom skull was determined. At the plane section area of bottom skull, three clearly visible zones with diverse area fraction and sizes of carbides that occur in them were found. The effect of area fraction of carbides on hardness of individual zones at the bottom skull with reference to hardness of obtained ingot was also characterized.
Comparison of the Investigations of Photonic Crystals Using SEM and Optical Technics
Authors: Starczewska Anna , Szala Janusz , Kępińska Mirosława , Nowak Marian , Mistewicz Krystian , Sozańska Maria
Published: March 2013

All over the world the investigations of nanophotonic structures called photonic crystals (PCs) are performed. These crystals have potential applications in optoelectronics, e.g. optical filters, antireflective surface coatings, lossless frequency selective mirrors. In Institute of Physics at Silesian Technical University the opal photonic crystals consisting of monodisperse spherical particles, that have diameters of several hundred nanometers, are produced using colloidal self-assembly technics. The main aim of this work is the comparison between pieces of information on morphology of photonic crystals that can be obtained from electron microscopy and from the angular characteristics of optical transmittance and reflectance. The morphology of the samples is characterized by scanning electron microscopy (SEM). Nanosphere diameters are established from statistical analysis of SEM images. The optical properties, which are determined by the photonic band structure, are studied by means of light transmission and reflection measurements. There is a relationship between the wavelength position of transmittance minimum or reflectance maximum and the diameter of the nanospheres. The size of nanospheres obtained from optical measurement results were compared with data obtained from SEM images.
Preparation and Characterization of Al-Si3N4 Composite Particles
Authors: Michalik Daniel , Valle Nathalie , Guillot Jérôme , Pawlik Tomasz , Sopicka-Lizer Malgorzata , Witkowska Anna , Myalski Jerzy
Published: March 2013

Fine Al-Si3N4 composite particles were prepared via mechanochemical processing of the coarse aluminum powder and submicron silicon nitride powder in order to obtain the core-shell structure of composite powder particles. It was expected that soft aluminum particles could form a thin coat on hard silicon nitride particles. The resultant particles were characterized through scanning and transmission electron microscopy and electron spectroscopes. Their particle size distribution, specific surface area, nitrogen/oxygen content and phase composition were also determined. Chemical analysis showed that limited oxidation occurred during mechanochemical processing. It has been found that a thin Al-enriched layer (larger than 10 nm) formed at some Si3N4 particles apart from the opposite effect if Si3N4 particles were occluded in coarser Al items. Discussion of the results is also presented.
Changes in the Molecular Structure of UHMW Polyethylene under the Influence of Thermal and Radiation Modification, as Well as Time
Authors: Maszybrocka Joanna , Czaja Piotr , Cybo Jerzy , Michniowski Jacek , Barylski Adrian
Published: March 2013

The paper presents the results of an examination of UHMW polyethylene type GUR1050 using the EPR, FTIR and SEM methods. The relationship between the number of radicals in the polymer and the absorbed dose of ionizing radiation has been shown. The radicals, being highly active macroparticles, disappear in time, so that after about a year their amount is reduced by approximately one order of magnitude. The disappearance of the radicals over time results in a change in EPR spectra, an increase in the degree of oxidation, and cross-linking. The most probable mechanisms are the formation of alkyl and allyl radicals and their gradual transitions, which lead to the absorption of atmospheric oxygen, and the recombination of radicals, which leads to the formation of cross linkages. Thermal treatment of the samples is an effective method of eliminating the radicals. Tribological tests and their analysis by means of SEM observation showed that the irradiated samples proved to have higher resistance to abrasion than the material that was not exposed to radiation.
Effect of Modification of Rare Earth Elements on the Morphology of Silicon Precipitates in the ZnAl22Cu3Si Alloy
Authors: Tomaszewska Agnieszka , Michalik Rafał , Woźnica Henryk
Published: March 2013

Properties of the Zn-Al-Cu alloys can be improved by partial or total replacement of the copper with silicon. The previous studies of the current authors have shown that in alloys with silicon addition its precipitates are not evenly distributed, which can lead to uneven wear of parts made of the Zn-Al-Cu alloy. The study of phenomena occurring during the crystallization of the ZnAl22Cu3Si alloy with ATD methods have shown that silicon does not form compounds and solid solutions with Zn and Al. In the examined alloy silicon is released as the primary even before the actual solidification of dendrites. It is not possible to reduce the irregular distribution of precipitates through heat treatment. Therefore it is important to assure the uniform distribution of precipitates of silicon already on the crystallization stage, e.g. by addition of rare earth elements. The purpose of this study was to determine the effect of rare earth elements on the morphology of silicon precipitates in the ZnAl22Cu3Si alloy. The investigated material were alloys containing 22 wt% Al, 3 wt % Cu and 1.5 wt% Si (Zn-remaining). The samples have been taken from the top, middle and bottom of the ingot. In order to determine the morphological characteristics of silicon precipitates a computer program: Met-Ilo developed in the Department of Materials Science, Silesian University of Technology was used. Changes of the area fraction and shape of precipitates in particular areas of the ingot were the subject of analysis in this work.
Model of Microstructure Development in Hot Deformed Magnesium Alloy AZ31 Type
Authors: Kuc Dariusz , Hadasik Eugeniusz
Published: March 2013

The paper presents a model of microstructure changes elaborated for magnesium alloy type AZ31. In previous papers, the function of flow stress was defined on the basis of uniaxial hot compression tests. On the basis of marked relaxation curves and quantitative tests of structure the softening indicators were defined together with elaboration of equations which describe the changes in the grain size. Marked coefficients of equations were introduced in the code of simulation program. Calculations were conducted for given temperature values from 450 ÷ 250°C and strain rate from 0.01 to 10 s-1, which correspond with rolling temperature range of this alloy. Prepared model will allow the proper choice of parameters in hot rolling process of this alloy to achieve the assumed microstructure.
Changes in Microstructure of GX12CrMoVNbn9-1 Cast Steel after Low Cycle Fatigue
Authors: Golański Grzegorz , Kolan Cezary , Kępa Jaonna
Published: March 2013

The paper presents the influence of low cycle fatigue (LCF) on the changes in microstructure of GX12CrMoVNbN9-1 cast steel after the 1040°C/12h/oil + 760°C/12h/air + 750°C/8h/furnace heat treatment. The examined cast steel was subjected to LCF at room temperature and at 550°C under the conditions of controlled total strain. It was observed that fatigue life of the cast steel decreased with increasing temperature. Cyclic softening was noticed at all temperatures. TEM quantitative characterization of the microstructure after LCF was carried out using: mean diameter of subgrains, density of dislocation and mean diameter of M23C6carbides. For the mean diameters of subgrains and M23C6carbides parameters, the histograms were made using STATISTICA 9 software. The research of quantitative parameters of the microstructure was carried out using AnaliSIS programs. Performed research of the quantitative parameters of microstructure has shown that the decrease in fatigue life with the temperature rise and cyclic softening of the cast steel after LCF are related to an increase in the lath width, the change from lath structure to cell/equaixed substructure, a decrease in dislocation density by the recovery process and a growth of M23C6carbides.
Quantitative Microstructural Analysis of Thermal Barrier Coatings Deposited on Inconel 625
Authors: Galant Grzegorz , Dulęba Jan , Toczek Sebastian , Dubiel Beata , Czyrska-Filemonowicz Aleksandra
Published: March 2013

The aim of the present work was to determine the influence of air plasma spraying (APS) parameters on the microstructure of thermal barrier coatings (TBC) consisting on NiCoCrAlY bond coat and yttria - stabilized zirconia (YSZ) top coat. The scope of the investigation involved macroscopic observation and microstructural analysis by means of light microscopy (LM) and scanning electron microscopy (SEM). For the varied parameters of deposition process quantitative analysis of coatings thickness, porosity, oxide inclusions, metallic inclusions, globular inclusions and cracks were performed. The results of quantitative analysis allowed to establish which APS conditions influence the particular microstructural parameters of TBC coatings.
Neural Network Based Reactive Navigation for Mobile Robot in Dynamic Environment
Authors: Krejsa Jiri , Vĕchet Stanislav , Ripel Tomas
Published: March 2013

When mobile robots are used among people, the best accepted motion related behavior is a human-like motion of the robot. Such behavior is difficult to obtain with commonly used finite state machine based planners, but can easily be evoked when human controls the robot. The paper presents the way of transforming such knowledge from human controller to reactive planner in the robot navigation module. Reactive planner is based on machine learning, neural networks in particular. The planner consists of two separate neural networks, one serving as predictor of dynamic obstacles behavior, second one serving as the reactive planner itself, producing desirable actions of the robot both in terms of velocity and direction. Planner was verified on real robot producing human-like behavior when used in real environment.
Using River Formation Dynamics Algorithm in Mobile Robot Navigation
Authors: Redlarski Grzegorz , Pałkowski Aleksander , Dąbkowski Mariusz
Published: March 2013

River Formation Dynamics is a heuristic optimization algorithm based on the manner, in which drops of water form the river bed. The idea is to imitate the movement of drops on the edges between given nodes thus performing a search based on their height, which is modified through the mechanism of soil erosion and sediment deposition. In this way decreasing gradients are constructed, and these are followed by subsequent drops to compose new gradients and reinforce the best ones. This paper presents implementation of the method in wheeled mobile robot path searching task in an environment with obstacles. At first, a concise introduction to theRFDalgorithm is presented, along with the problems requirements. In the main part a simulation test has been performed using the algorithm to find the shortest route from the starting point to the goal. The tests were made with different landscape layouts, measuring the computation time. The last section presents a real life implementation of the algorithm using aPioneer P3-DXmobile robot. The validity of this solution is discussed, as well as any modifications, along with a brief comparison with a similar, popular search path algorithm.
Development of a Model for the Intake Channel within a MRCA Turbine Engine in Order to Analyze Intake Vortex Phenomena
Authors: Kozakiewicz Adam
Published: March 2013

Turbine engines need to produce the thrust from several to about one thousand kilograms of the air per second depending on the engine type. Due to the demand for such a significant amount of the air a unique three dimensional field of speed occurs in the area of the intake vicinity. The characteristic feature of this field, when the engine runs on the ground, is generation of an inlet stagnation line and a stagnation point. In case of the aircraft engines, a vortex is developed chiefly due to external disturbances e.g. because of crosswind gusts or a stream of engine exhaust from another aircraft. This may lead to serious damage of fan or compressor blades and, additionally, affect the stability of engine operation. This paper addresses selected issues related to development of a model for a turbine engine intake, describes the course of modeling procedures for both the engine intake and its vicinity and selection of boundary conditions as well as the solution algorithm that involves the numerical analysis of the intake vortex formation. The purpose of the analyses performed was to define how variations of the engine speed, the angle and direction of wind gusts affect formation of the intake vortex.
Modeling, Simulation and Control of Microelectromechanical Flying Insect
Authors: Sibilski Krzysztof , Żyluk Andrzej
Published: March 2013

This paper presents modeling, simulation, and control of a flapping wing Micromechanical Flying Insect (MFI) called Entomopter. The overall geometry of this MFI is based on hummingbirds and large insects. This paper presents methods for investigation of MFI aerodynamics, flight dynamics, and control. The simulation results reveal important information regarding the behavior of the system, that could be used in future designs
UAV Avionics System Software Development Using Simulation Method
Authors: Brzozowski Bartosz , Sobieraj Wiesław , Wojtowicz Konrad
Published: March 2013

During last few years avionics system research platform was invented at the Military University of Technology. This modular simulator allows user to design and verify avionics system software using hardware-in-the-loop technique. Mathematical model of an airplane under tests is implemented on a high-performance computer which response to all control signals and environmental disturbances. Environment is simulated on a separate computer which can also visualize orientation and movement of the airplane. Plane structure and aerodynamic features as well as control data can be modified accordingly to user needs. The third PC is used as an interface unit between research platform and main computational unit of the avionics system. This device can send and receive information in real-time using various data protocols and interfaces depending on sensors and actuators that are planned to be used in real system. Those three computers work in a local area network and exchange data using Gigabit Ethernet standard. Possibility to simulate behavior of an UAV controlled by the developed avionics system implemented on an embedded computer working in hardware-in-the-loop mode on the platform, allows software developer to debug any part of the application in various environment conditions very close to reality. Research platform gives also the possibility to modify algorithm and adjust its parameters in real-time to verify suitability of the implemented avionics system software for the particular UAV. The avionics system software developed using this simulation method minimize expensive in-flight tests and assure failsafe performance after first successful flight
Controlled Conditioning System for the Electromagnetic Generator Supporting an MR Damper: Prototyping and Testing
Authors: Rosół Maciej , Sapiński Bogdan , Knapik Mateusz
Published: March 2013

The paper presents the conditioning system prototype intended for an electromagnetic generator supporting an MR damper in self-powered vibration reduction systems. The system engineered in the form of an electronic circuit comprises the following blocks: the MR damper control coil supply, self-powering, measurement and the microcontroller. The self-powering function consists in supplying the microcontroller from the generator, assuming that the voltage is larger than that required to power the microcontroller, otherwise the microcontroller will take up energy from a battery since the system has also the battery charging option. The performance of the system was verified through experiments where it acted as a component of a vibration reduction system.
Elastic Interdigital Transducers for Lamb Wave Generations
Authors: Mańka Michał , Martowicz Adam , Rosiek Mateusz , Uhl Tadeusz
Published: March 2013

During recent years structural health monitoring (SHM) systems have gained growing attention. Widely applied methods in SHM are methods based on the ultrasonic Lamb waves (LWs) which are also known as plate waves. LWs may be generated and sensed using different types of transducers and their selection is essential for the SHM systems performance. Among transducers used for generation and sensing of such waves, Interdigital Transducers (IDTs) are ones of the most promising types. Their main advantages are: mode selectivity, high excitation strength, wave directivity, small sizes and relatively low cost. In most cases IDTs are made of piezoceramics or piezoelectric polymers what makes them stiff and fragile. Contrary to the piezoceramic transducers, the ones based on piezocomposites (i.e.: macro-fiber composite) are flexible with the comparable efficiency of piezoelectric effects. The MFC transducers are usually optimized as actuators and they are not designed to any specific frequency. It appears, however, that sparse comb-like electrodes used in interdigital transducers create very interesting properties of mode selectivity. In the paper, after the introduction and short discussion about advantages and disadvantages of the IDTs, a novel type of the interdigital transducer, based on elastic macro-fiber composite, is presented. Next, the results of the numerical and experimental tests of the MFC based IDT designed for the A0 mode excitation in a 4mm-thick aluminium plate is presented. In the final part of the paper advantages and disadvantages of the investigated transducer are discussed.
Haptic Devices Based on Planar Stepping Motors Introductory Concept
Authors: Huścio Tomasz , Kołodziejczyk Waldemar
Published: March 2013

The paper describes concept of the usage of the planar stepping motor (Sawyer motor) as a haptic device. The principle of operation of a planar stepping motor is presented.