Kelvin Probe Force Microscopy (KPFM) characterization of lanthanum lutetium oxide high-k dielectric thin films

Lanthanum lutetium oxide (LaLuO3) thin films were investigated considering their perspective application for industrial microelectronics. Scanning probe microscopy (SPM) techniques permitted to visualize the surface topography and study the electric properties. This work compared both the material properties (charge behavior for samples of 6 nm and 25 nm width) and the applied SPM modes. Particularly, Kelvin probe force microscopy (KPFM) was applied to characterize local potential difference with high lateral resolution. Measurements showed the difference in morphology, chargeability and charge dissipation time for both samples. The polarity effect was detected for this material for the first time. Lateral spreading of the charged spots indicate the diffusive mechanism to be predominant in charge dissipation. This allowed to estimate the diffusion coefficient and mobility. Using simple electrostatic model it was found that charge is partly leaking into the interface oxide layer.

Peak Force Kelvin Probe Force Microscopy Investigation of ZrO2 Nanocomposites for Hygroelectricity Power Element

ZrO2 nanocomposites were investigated considering their perspective application in hygroelectric power elements. Scanning probe microscopy (SPM) techniques allowed to visualize the surface topography and electrical properties. In this work was compared spacial charge behaviour of sample in humid and dry air conditions. Also different SPM modes were compared. Kelvin probe force microscopy (KPFM) was applied to characterize the spacial charge distribution on surface of the sample. Measurements showed, that trapped charge is not dissipated and can be manipulated with low voltages. Humidity influence on the electric potential of the sample was shown.

Relationship of breast fillet deboning time to shear force, pH, cooking loss and color in broilers stunned by high electrical current

Selostus: Korkealla virranvoimakkuudella tainnutettujen broilereiden rintafileen irroitushetken vaikutus lihaksen leikkausvoiman vastukseen, pH:hon, keittohävikkiin ja väriin

Fibre-reinforced composites as root canal posts

Fibre-reinforced composite (FRC) root canal posts are suggested to have biomechanical benefits over traditional metallic posts, but they lack good adhesion to resin composites. The aim of this series of studies was to evaluate the adhesion of individually formed fibre-reinforced composite material to composite resin and dentin, as well as some mechanical properties. Flexural properties were evaluated and compared between individually formed FRC post material and different prefabricated posts. The depth of polymerization of the individually formed FRC post material was evaluated with IR spectrophotometry and microhardness measurements, and compared to that of resin without fibres. Bonding properties of the individually formed FRC post to resin cements and dentin were tested using Pull-out- and Push-out-force tests, evaluated with scanning electron microscopy, and compared to those of prefabricated FRC and metal posts. Load-bearing capacity and microstrain were evaluated and failure mode assessment was made on incisors restored with individually formed FRC posts of different structures and prefabricated posts. The results of these studies show that the individually polymerized and formed FRC post material had higher flexural properties compared to the commercial prefabricated FRC posts. The individually polymerized FRC material showed almost the same degree of conversion after light polymerization as monomer resin without fibres. Moreover, it was found that the individually formed FRC post material with a semiinterpenetrating polymer network (IPN) polymer matrix bonded better to composite resin luting cement, than did the prefabricated posts with a cross-linked polymer matrix. Furthermore, it was found that, contrary to the other posts, there were no adhesive failures between the individually formed FRC posts and composite resin luting cement. This suggests better interfacial adhesion of cements to these posts. Although no differences in load-bearing capacity or microstrain could be seen, the incisors restored with individually formed FRC posts with a hollow structure showed more favourable failures compared to other prefabricated posts. These studies suggest that it is possible to use individually formed FRC material with semi-IPN polymer matrix as root canal post material. They also indicate that there are benefits especially regarding the bonding properties to composite resin and dentin with this material compared to prefabricated FRC post material with a cross-linked matrix. Furthermore, clinically more repairable failures were found with this material compared to those of prefabricated posts.

The Dynamics of Force Fluctuations in Shear Granular Flows

Tämän työn tavoitteena oli tutkia rakeisen materiaalin kinematiikkaa ja rakentaa koelaitteisto rakeisen materiaalin leikkausjännitysvirtauksien tutkimiseen. Kokeellisessa osassa on keskitytty sisäisiin voimaheilahteluihin ja niiden ymmärtämiseen. Teoriaosassa on käyty läpi rakeisen materiaalin yleisiä ominaisuuksia ja lisäksi on esitetty kaksi eri tapaa mallintaa fysikaalisien ominaisuuksien heilahteluja rakeisessa materiaalissa. Nämä kaksi esitettyä mallinnusmenetelmää ovat skalaarinen q-malli ja simulointi. Skalaarinen q-malli määrittelee jokaiseen yksittäiseen rakeeseen kohdistuvan jännityksen, rakeen ollessa osa 2- tai 3-dimensionaalista asetelmaa. Tämän mallin perusidea on kuvata jännityksien epähomogeenisuutta, joka johtuu rakeiden satunnaisasettelusta. Simulointimallinnus perustuu event-driven algoritmiin, missä systeemin dynamiikkaa kuvataan yksittäisillä partikkelien törmäyksillä. Törmäyksien vaiheet ratkaistiin käyttämällä liikemääräyhtälöitä ja restituution määritelmää. Teoriaosuudessa käytiin vielä pieniltä osin läpi syitä jännitysheilahteluihin ja rakeisen materiaalin lukkiintumiseen. Tutkimuslaitteistolla tutkittiin rakeisen materiaalin käyttäytymistä rengasmaisessa leikkausjännitysvirtauksessa. Tutkimusosuuden päätavoitteena oli mitata partikkelien kosketuksista ja törmäyksistä johtuvia hetkellisiä voimaheilahteluja rengastilavuuden pohjalta. Rakeisena materiaalina tutkimuksessa käytettiin teräskuulia. Jännityssignaali ajan funktiona osoittaa suurta heilahtelua, joka voi olla jopa kertalukua keskiarvosta suurempaa. Tällainen suuren amplitudin omaava heilahtelu on merkittävä haittapuoli yleisesti rakeisissa materiaaleissa käytettyjen jatkuvuusmallien kanssa. Tällainen heilahtelu tekee käytetyt jatkuvuusmallit epäpäteviksi. Yleisellä tasolla jännityksien todennäköisyysjakauma on yhtäpitävä skalaarisen q-mallin tuloksien kanssa. Molemmissa tapauksissa todennäköisyysjakaumalla on eksponentiaalinen muoto.

An Optimum Coating Colour Formula for CSWO-printing

Pigmenttipäällystyksen tarkoituksena on parantaa painopapereiden pintaominaisuuksia. Tämän työn tarkoituksena oli löytää sopiva päällystyspasta päällystetylle coldset-paperille. Kirjallisuusosassa on käsitelty coldset-painatusta ja sen ongelmia. Päällystysmenetelmän perusteita, pastan ominaisuuksia ja niiden vaikutusta päällystystulokseen on myös käsitelty. Lisäksi on esitelty joitakin päällystetyn paperin pinnantutkimusmenetelmiä. Kokeellisessa osassa on tutkittu erilaisten pastakoostumusten ja päällystemäärien sekä kalanteroinnin vaikutusta paperin painettavuuteen. Paperit on päällystetty Helicoaterilla ja joitakin pastoja on testattu myös pilot-mittakaavaisessa päällystyksessä. Selitystä paperin käyttäytymiseen painatuksessa on etsitty päällystetyn paperin pintarakenteesta. Paras painettavuus saavutetaan päällysteellä, jossa pigmenttinä on vain karbonaatti. Painojälkeä voidaan parantaa käyttämällä kalsinoitua kaoliinia yhdessä karbonaatin kanssa, mutta tämän päällysteen pintalujuus ei ole riittävä CSWO-painatukseen. Tärkkipigmentti parantaa veden ja painovärin absorptiota ja siten tekee painetun tuotteen kuivemmaksi ja miellyttävämmän tuntuiseksi, mutta aiheuttaa smearingia. Tämä johtuu liian nopeasta musteen asettuvuudesta. "Pehmeä" SB-lateksi soveltuu paremmin offset-painatukseen kuin "kova" lateksi, joka sisältää myös PVAc:ta. "Pehmeällä" lateksilla saadaan parempi pintalujuus ja painojälki kuin "kovalla" lateksilla. Paperin pölyävyyttä painatuksessa voidaan vähentää nostamalla päällystemäärää ja laskemalla pastan kuiva-ainepitoisuutta. Kalanteroinnilla ei pintalujuutta tai painojälkeä voida parantaa. Selitys tutkimuksessa käsiteltyjen papereiden painojäljelle ja painettavuudelle löydetään tutkimalla päällysteen pintarakennetta. Painojälkeen vaikuttaa eniten päällysteen peittoaste. Huonoa peittävyyttä voidaan parantaa nostamalla päällystemäärää. Pölyäminen painatuksessa johtuu pigmenteistä, jotka eivät ole sidottuja paperin pintaan. Tämä taas johtuu pastan huonosta vesiretentiosta. Hyödyllisintä tietoa näiden papereiden pintarakenteesta saadaan tutkimalla pintaa pyyhkäisyelektonimikroskoopilla (SEM), atomivoimamikroskoopilla (AFM) ja laserindusoidulla plasmaspektrometrilla (LIPS). LIPSin etuna on se, että päällystemääräjaukauma voidaan määrittää sekä x-y- että z-suunnassa samanaikaisesti samasta kohdasta. LIPSissä myös näytteen preparointitarve on hyvin vähäinen.

Characterisation of pigment particles by scanning electron microscope and image analysis programs

Coating and filler pigments have strong influence to the properties of the paper. Filler content can be even over 30 % and pigment content in coating is about 85-95 weight percent. The physical and chemical properties of the pigments are different and the knowledge of these properties is important for optimising of optical and printing properties of the paper. The size and shape of pigment particles can be measured by different analysers which can be based on sedimentation, laser diffraction, changes in electric field etc. In this master's thesis was researched particle properties especially by scanning electron microscope (SEM) and image analysis programs. Research included nine pigments with different particle size and shape. Pigments were analysed by two image analysis programs (INCA Feature and Poikki), Coulter LS230 (laser diffraction) and SediGraph 5100 (sedimentation). The results were compared to perceive the effect of particle shape to the performance of the analysers. Only image analysis programs gave parameters of the particle shape. One part of research was also the sample preparation for SEM. Individual particles should be separated and distinct in ideal sample. Analysing methods gave different results but results from image analysis programs corresponded even to sedimentation or to laser diffraction depending on the particle shape. Detailed analysis of the particle shape required high magnification in SEM, but measured parameters described very well the shape of the particles. Large particles (ecd~1 µm) could be used also in 3D-modelling which enabled the measurement of the thickness of the particles. Scanning electron microscope and image analysis programs were effective and multifunctional tools for particle analyses. Development and experience will devise the usability of analysing method in routine use.

Electric field calibration method for scanning electron microscope

This paper proposes a calibration method which can be utilized for the analysis of SEM images. The field of application of the developed method is a calculation of surface potential distribution of biased silicon edgeless detector. The suggested processing of the data collected by SEM consists of several stages and takes into account different aspects affecting the SEM image. The calibration method doesn’t pretend to be precise but at the same time it gives the basics of potential distribution when the different biasing voltages applied to the detector.

Drag force and frictional resistances in vertically vibrated dense granular media

The objective of this thesis is to shed light on the vertical vibration of granular materials for potential interest in the power generation industry. The main focus is investigating the drag force and frictional resistance that influence the movement of a granular material (in the form of glass beads) contained in a vessel, which is subjected to sinusoidal oscillation. The thesis is divided into three parts: theoretical analysis, experiments and computer simulations. The theoretical part of this study presents the underlying physical phenomena of the vibration of granular materials. Experiments are designed to determine fundamental parameters that contribute to the behavior of vibrating granular media. Numerical simulations include the use of three different software applications: FLUENT, LS-DYNA and ANSYS Workbench. The goal of these simulations is to test theoretical and semiempirical models for granular materials in order to validate their compatibility with the experimental findings, to assist in predicting their behavior, and to estimate quantities that are hard to measure in laboratory.

Sensor Fusion of Proprioception, Force and Vision in Estimation and Robot

Sensor-based robot control allows manipulation in dynamic environments with uncertainties. Vision is a versatile low-cost sensory modality, but low sample rate, high sensor delay and uncertain measurements limit its usability, especially in strongly dynamic environments. Force is a complementary sensory modality allowing accurate measurements of local object shape when a tooltip is in contact with the object. In multimodal sensor fusion, several sensors measuring different modalities are combined to give a more accurate estimate of the environment. As force and vision are fundamentally different sensory modalities not sharing a common representation, combining the information from these sensors is not straightforward. In this thesis, methods for fusing proprioception, force and vision together are proposed. Making assumptions of object shape and modeling the uncertainties of the sensors, the measurements can be fused together in an extended Kalman filter. The fusion of force and visual measurements makes it possible to estimate the pose of a moving target with an end-effector mounted moving camera at high rate and accuracy. The proposed approach takes the latency of the vision system into account explicitly, to provide high sample rate estimates. The estimates also allow a smooth transition from vision-based motion control to force control. The velocity of the end-effector can be controlled by estimating the distance to the target by vision and determining the velocity profile giving rapid approach and minimal force overshoot. Experiments with a 5-degree-of-freedom parallel hydraulic manipulator and a 6-degree-of-freedom serial manipulator show that integration of several sensor modalities can increase the accuracy of the measurements significantly.

Electric field measurements using scanning electron microscope

The main idea of this diploma work is to study electric field distribution on the micro level. For this purpose a silicon edgeless detector was chosen as the object of investigation and scanning electron microscope as an investigation tool. Silicon edgeless detector is an important part of installation for studying proton-proton interactions in TOTEM experiment at Large Hadron Collider. For measurement of electric field distribution inside scanning electron microscope a voltage contrast method was applied.

National Library and Library Network in Finland - Cooperation Being the Driving Force of Success

Kristiina Hormia-Poutasen esitys Danish Research Association -tapahtumassa Tanskassa 15.9.2011

Novel force control methods in a teleoperation system of a hydraulic slider

The objective of the this research project is to develop a novel force control scheme for the teleoperation of a hydraulically driven manipulator, and to implement an ideal transparent mapping between human and machine interaction, and machine and task environment interaction. This master‘s thesis provides a preparatory study for the present research project. The research is limited into a single degree of freedom hydraulic slider with 6-DOF Phantom haptic device. The key contribution of the thesis is to set up the experimental rig including electromechanical haptic device, hydraulic servo and 6-DOF force sensor. The slider is firstly tested as a position servo by using previously developed intelligent switching control algorithm. Subsequently the teleoperated system is set up and the preliminary experiments are carried out. In addition to development of the single DOF experimental set up, methods such as passivity control in teleoperation are reviewed. The thesis also contains review of modeling of the servo slider in particular reference to the servo valve. Markov Chain Monte Carlo method is utilized in developing the robustness of the model in presence of noise.