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Kieli: | eng |
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Julkaisija: | Delft : TU Delft Open 2008- |
ISSN: |
2589-8019 |
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This study was focused on investigation of new glass-system with the following composition: (100- x-0.25)(75NaPO₃ – 25CaF₂) – xFe₂O₃ – 0.25Er₂O₃ with x = 0, 1.5, 2.5, 5, and 10 in mol%. The new system is contrasting with the previous studies due to the integration of Fe₂O₃ into the composition. The aim of the study was to improve the thermal stability of the glass while ensuring the preservation of the nucleation and growth mechanisms. Glasses were prepared using a standard melting process and characterized, after which the glass-ceramics were made by controlled heat treatment of the as-prepared glasses. The results demonstrate improved thermal stability, but along with loss in fluorine content during melting, which prevented CaF₂-crystals formation in glass-ceramics. The use of quartz crucible induces a change in fluorine content and, as a consequence, the nucleation and growth mechanisms.
We present an alternate method to close the master equation representing the continuous time dynamics of interacting Ising spins. The method makes use of the theory of random point processes to derive a master equation for local conditional probabilities. We analytically test our solution studying two known cases, the dynamics of the mean-field ferromagnet and the dynamics of the one-dimensional Ising system. We present numerical results comparing our predictions with Monte Carlo simulations in three different models on random graphs with finite connectivity: the Ising ferromagnet, the random field Ising model, and the Viana-Bray spin-glass model.
The purpose of this thesis was prove the possibility of using glass in buildings as a load-bearing element. For centuries, its use is limited to functions such as window glazing. In recent decades, the improvement of science and industry has allowed the use glass as a structural element. However, the design of such structures is still problematic. The study was conducted at the architectural workshop "Studio 44" as an example of glass covering of courtyards in the reconstruction of the General Staff Building of East Annex, located between the Palace Square and River Moika. Structures of glass coating is a system of interconnected diagonal steel trusses and glass beams, which consist of a multilayer laminated glass. For the calculation of the glass beam a design-computer complex StructureCAD v.11.1 was used, realizing the finite element method in the form of the method of displacement. To confirm the calculations conducting tests was necessary. The testing of the glass beam of the General Staff will be made at CRIBS Kucherenko (Central Research Institute of Building Structures) in Moscow. The test models will be scheduled on uniform and no-uniform loads. The results of the calculations and the tests proved the possibility of using glass as a load-bearing element, but because of the high cost of the material, the use is not widespread. This is compounded by the lack of normative documents for the calculations bearing glass. For each design a special certificate and confirmed tests are required.
While extensive research efforts have been devoted to understand the dynamics of chemically and structurally simple glass-forming liquids (SGFLs), the viscoelasticity of chemically and structurally complex glass-forming liquids (CGFLs) has received only little attention. This study explores the rheological properties of CGFLs in the vicinity of the glass transition. Bitumen is selected as the model material for CGFLs due to its extremely complex chemical composition and microstructure, fast physical aging and thermorheological simplicity, and abundant availability. A comprehensive rheological analysis reveals a significant broadening of the glass transition dynamics in bitumen as compared to SGFLs. In particular, the relaxation time spectrum of bitumen is characterized by a broad distribution of long relaxation modes. This observation leads to the development of a new constitutive equation, named the broadened power-law spectrum model. In this model, the wide distribution of long relaxation times is describedby a power-law with positive exponent and a stretched exponential cut-off, with parameter β serving as a measure of the broadness of the distribution. This characteristic shape of the bitumen spectrum is attributed to the heterogeneous freezing of different molecular components of bitumen, i.e., to the coexistence of liquid and glassy micro-phases. Furthermore, as this type of heterogeneous glass transition behavior can be considered as a general feature of complex glass-forming systems, the broadened power-law spectrum model is expected to be valid for all types of CGFLs. Examples of the applicability of this model in various complex glass-forming systems are given.
The objective of this project was to investigate the effect of addition of Ag2O on the spectroscopic properties of tellurite glasses and examine if silver nanoparticles can be grown in such glasses to enhance their spectroscopic properties. First, the impact of silver oxide concentration on the glass network was studied, and then the effect of heat-treatment duration on the growth of the silver nanoparticles was investigated. Glasses with the composition (100-x-y) (70TeO2-20ZnO-10Bi2O3)-xAg2O-yEr2O3 with x = 0, 0.5, 1, 2 and 4 and y = 0 and 2.5 in mol% were prepared using the conventional melting quenching method. Afterwards glasses were heat-treated at Tg + 20 °C for 2, 5 and 17 hours to eventually grow the silver nanoparticles. The progressive addition of Ag2O was found to modify the thermal and spectroscopic properties of the glass, increasing the thermal stability against crystallization due to the depolymerization of the tellurite network. However, even though the addition of Ag2O modified the glass network, it did not change the site of Er3+-ions. However, the highly Ag containing glasses exhibit lower intensity of upconversion when pumped at 980 nm suggesting that the Er-Er distance increases when adding Ag2O probably due to the depolymerization of the tellurite network. A heat-treatment of the glasses at their Tg + 20 °C changed their color and their transparency due to crystallization, which was confirmed using XRD. The XRD pattern of the heat-treated glass exhibit similar sharp peaks which belong to the Bi4TeO8 crystals. In the XRD pattern and absorption spectra of the heat-treated glasses, there was no evidence of the precipitation of silver nanoparticles occurring during the heat-treatment. Additionally, the shapes of the Er3+ emission spectra remained similar after heat-treatment indicating that the Er3+ ions remained in the amorphous part of glass. However, the intensity of the conversion was found to increase after heat-treatment only in the low Ag containing glasses suggesting that the Er-Er distance decreases in the polymerized glasses due to the precipitation of Bi4TeO8 crystals. In the depolymerized network, the Er-Er distance does not seem to be impacted by the precipitation of Bi4TeO8 crystals.
All finished products available for consumer use is an assemble of different raw materials to yield the final commodity. Glass is an important product that is used in all parts of the world. Some finished glass products available for consumption are entirely composed of glass whereas others reflect a small percentage of glass in their final structure. Regardless of how much quantity of glass is present in the final products, silica has a very important role to play in all glass processes. Silica sand is a natural in-dispensable raw material in the glass industry for the processing of different variety of products. This thesis report does not only illustrate the role and influence silica sand has on the quality of glass or expose its congenital features that makes it suitable for use in preference to other types of sand, but it will also examine techniques that are employed to enhance its purity for usage in producing high quality products. More emphasis will equally be laid on its importance in the production of different commodities and prospects its availability in the future since the demand for silica sand is high. The report elucidates that the continuous high use of silica sand to satisfy consumer needs will eventually lead to shortage and creates the awareness that different sand types should be tested and used to re-duce the total dependence of silica sand in glass and other factories.
Bioactive glasses are surface-active ceramic materials which support and accelerate bone growth in the body. During the healing of a bone fracture or a large bone defect, fixation is often needed. The aim of this thesis was to determine the dissolution behaviour and biocompatibility of a composite consisting of poly(ε-caprolactone-co-DL-lactide) and bioactive glass (S53P4). In addition the applicability as an injectable material straight to a bone defect was assessed. In in vitro tests the dissolution behaviour of plain copolymer and composites containing bioactive glass granules was evaluated, as well as surface reactivity and the material’s capability to form apatite in simulated body fluid (SBF). The human fibroblast proliferation was tested on materials in cell culture. In in vivo experiments, toxicological tests, material degradation and tissue reactions were tested both in subcutaneous space and in experimental bone defects. The composites containing bioactive glass formed a unified layer of apatite on their surface in SBF. The size and amount of glass granules affected the degradation of polymer matrix, as well the material’s surface reactivity. In cell culture on the test materials the human gingival fibroblasts proliferated and matured faster compared with control materials. In in vitro tests a connective tissue capsule was formed around the specimens, and became thinner in the course of time. Foreign body cell reactions in toxicological tests were mild. In experimental bone defects the specimens with a high concentration of small bioactive glass granules (<45 μm) formed a dense apatite surface layer that restricted the bone ingrowth to material. The range of large glass granules (90-315 μm) with high concentrations formed the best bonding with bone, but slow degradation on the copolymer restricted the bone growth only in the superficial layers. In these studies, the handling properties of the material proved to be good and tissue reactions were mild. The reactivity of bioactive glass was retained inside the copolymer matrix, thus enabling bone conductivity with composites. However, the copolymer was noticed to degradate too slowly compared with the bone healing. Therefore, the porosity of the material should be increased in order to improve tissue healing.
Gadolinium-doped silica glass was prepared, using the sol-gel route, for ionizing radiation dosimetry applications. Such a glassy rod was drawn to a cane at a temperature of 2000 °C. The structural and optical properties of the obtained material were studied using Raman, optical absorption, and photoluminescence spectroscopies. Thereafter, a small piece of this Gd-doped scintillating cane was spliced to a transport passive optical fiber, allowing the remote monitoring of the X-ray dose rate through a radioluminescence (RL) signal. The sample exhibited a linear RL intensity response versus the dose rate from 125 µGy(SiO2)/s up to 12.25 Gy/s. These results confirm the potentialities of this material for real-time remote ionizing radiation dosimetry.
Phosphate laser glasses and glass ceramics are versatile materials, whose potential as a fiber laser core material has been studied. Often the lasing properties of a phosphate glass ceramic is not sufficient for laser applications, partly because the high water concentrations of phosphate glasses and glass ceramics lower the optical and luminescence powers of the material. Therefore, the goal of this study was to develop a new ytterbium doped oxyphosphate glass system with enhanced water resistance and lasing properties, and to study its compatibility to prepare a glass-ceramic, ultimately to be used in fiber laser glass cores. An existing glass composition of (98.75) [(90)NaPO3 – (10)Na2O] – (1.25)Yb2O3 was modified by adding metal oxides into it, with the aim to enhance its water resistance and lasing properties. The added metal oxides were chosen to be Al2O3, TiO2 and ZnO. The prepared glasses were also heat-treated into glass ceramics. The absorption coefficients and absorption cross-sections at approximately 975 nm were measured to evaluate the optical properties, and emission intensities and emission cross-sections were measured to evaluate the luminescence properties. The IR-spectra of the glasses were measured to check the presence of water in the glasses. Thermal analysis (DSC) and density measurements were conducted to evaluate the thermal and physical properties of the glasses. Also, the heat-treated glasses were studied with an XRD, to analyze their crystalline structure and composition. The addition of Al2O3 and TiO2 leads to an increase in the measured thermal properties, while the addition of ZnO showed no impact on the thermal properties. Addition of all the oxides showed an increase on the optical and luminescence properties, and a clear decrease on the water content of the glasses. Heat-treatment leads to the growth of a crystalline phase of NaYb(P2O7) in all the glasses. Overall, the new glass compositions appear to be more water resistant than the base glass. The new glasses have increased optical and luminescence properties, and show a promise to be turned into optically active glass ceramics, possibly to be further used in fiber lasers. Further research should be done on the long-term water absorption of these and similar glasses. The heat-treatment of the glasses should also be further optimized to achieve transparent glass ceramic, rich with Yb3+ containing crystalline phases in the bulk. Additionally, similar research needs to be done with different metal oxides, for example MgO and Li2O which have been shown to be promising in other studies, to determine the best candidate for fiber laser applications.
Metallic and permanent bone implants expose trauma patients to recurring fractures and infections even after years of implantation. Metallic implants also predispose for stress shielding phenomenon and fibrous capsule formation driving the research to find more biocompatible solutions for implant materials and construction. Bioactive materials such as bioactive glasses have proven to be effective at repairing large bone defects, cure and prevent bone infections during the healing process, and they are completely biodegradable. Our goal is to create novel biodegradable composite implants which are comprised of polymer matrices reinforced with bioactive glass fibres. With such composite, it could be possible to create a load bearing and biodegradable implant that would also be osteoinductive and antimicrobial with customizable degradation time. For this, we have chosen 3 different types of bioactive glass compositions 1-06, 13-93, and 18-06 that represent fast, medium, and slow bioactivity profiles, respectively, according to the literature. We prepared the glasses, pulled them into fibers and performed a dissolution test and SEM analysis to assess the bioactivity profile of the glasses in fiber form. The secondary goal was to evaluate the usability of these fibers as structural components. The results from the dissolution test in simulated body fluid and SEM analysis confirmed that the 1-06 glass fibers were bioactive. The 13-93 and 18-06 fibers did not respond to SBF, start leeching ions or form a calcium phosphate layer. However, the 13-93 blocks, that were used as the positive control, did have a stronger response to the SBF than the 1-06. This suggests that the 1-06 fibers might represent a medium bioactivity profile instead of fast. These results might also mean that the 13-93 and 18-06 fibers were not immersed long enough for them to dissolute and they might still represent the suggested bioactivity profiles. Although, the glass composition of the fibers was altered during the fiber pulling process and the fibers had different composition than intended.
In this experimental study, we explore the broadening of the glass transition in chemically and structurally complex glass-forming liquids (CGFLs) by means of thermal and rheological characterization techniques. Petroleum fluids with different levels of chemical and structural complexity are used as model materials. Thermal characterization by temperature-modulated differential scanning calorimetry (TMDSC) reveals a systematic increase in the width of the glass transition region ΔT g with increasing chemical and structural complexity. The broadening of the glass transition is also strongly reflected in the linear viscoelastic properties that are measured by small-diameter parallel plate rheometry. Most notably, this is observed as the broadening of the relaxation time spectrum at long times. The recently proposed broadened power-law spectrum model is used to describe the constitutive behavior of the investigated petroleum fluids. In this model, the stretching parameter β serves as a quantitative measure of the spectral broadening. A strong power-law correlation is found between ΔT g and β, manifesting a relationship between the broadness of the calorimetric and viscoelastic glass transition in CGFLs.
Although phase relations in the Na2O-CaO-SiO2 system are vital to melting and thermal treatments in glass and glass-ceramics industries, the available data for thermodynamic modeling are mostly based on reports published in 1920s and 1950s. The present investigation verifies the formation of solid solutions of Na2CaSiO4 and Na2Ca2Si2O7 which have previously assumed to be stoichiometric compounds. The impact of these solid solutions on the features of the phase diagram were investigated using the equilibration-quenching-EDS/EPMA technique. The data were reported as liquidus projections and in isothermal sections within the temperature range of 1000 and 1400 °C. Ten primary phase fields were identified, namely SiO2, Na2Ca3Si6O16, combeite, Na4CaSi3O9ss, CaSiO3, Na2CaSiO4ss, Na2Ca2Si2O7ss, Na2Ca6Si4O15, Ca3Si2O7 and Ca2SiO4. In addition, some novel liquidus data and invariants points were examined in more detail. The fundamental data obtained can be employed for the thermodynamic reassessment of the Na2O-CaO-SiO2 system. The present study also discusses the findings and their impact on melting and annealing processes during the manufacture of glass and glass-ceramics.
Phosphate glasses are very interesting due to several properties, such as good thermal and mechanical stabilities, high transparency, low refractive index, low melting temperature and high gain density (Wa,03; Pr,08; Hr,13; Do,15). Most importantly, they exhibit higher solubility for RE ions, without clustering effect, compared to silica based glasses (Sh,05). Phosphate glasses are used for optical fibers and laser gain media applications (Mi,91; Su,15) and also for medical applications (Ne,08). Second paragraph Oxyfluoride glasses combine advantages of fluoride and oxide glasses. Fluoride glasses have lower phonon energy but oxide glasses usually have much better chemical durability, thermal stability and mechanical strength than the fluoride glasses (Cu,16). As reported by (Cu,16) novel oxyfluoride phosphate glasses combining all these advantages are promising materials for bioactive and optical applications. These glasses can be made with addition of rare-earth ions which are used for a wide range of applications such as telecommunications, light detection and ranging (LIDAR), solar panels, spectroscopy, and bio-imaging (De,98). In this thesis, Er3+ ions which show characteristic 1530 nm wavelength emission, have been used. Moreover, dopants like TiO2, MgO and ZnO which affect thermal, structural and luminescence properties are often added to phosphate based glasses (Po,06; Cu,16). To obtain better thermal and mechanical properties, glass-ceramic can be produced from glasses. This is done by using heat treatment process which allows one to achieve controlled crystallization of glass. PeL properties of glass and glass-ceramic can be utilized in biophotonic PeL phosphate glasses. Such glasses can be used as bone implant, the mineralization of which can be tracked in-vivo. As reported by (Zh,16), PeL glass-ceramics can be produced using direct doping method in which PeL microparticles are added to the glass melt. Finally, the feasibility of patterning microstructured 2D gratings at the surface of phosphate glass is investigated. The ability to carry out glass micropatterning in a cost- and time-effective fashion is crucial for producing devices and structures based on these materials for the mentioned applications. A potential use of the fabricated 2D gratings for monitoring phosphate glass degradation in wet environments through optical diffraction measurements is also introduced. In the first and second chapter, the basic knowledge about glasses and materials and methods are described, respectively. In the results and discussion part, the impact of the glass composition on the glass is first investigated. Then, the effect of the heat treatment on produced glass-ceramic is described. Finally, the work on PeL oxyfluoride biophotonic glass-ceramics and patterning is presented. The impact of melting parameters and PeL microparticles concentration on luminescence properties is discussed. Conclusions and next steps are summarized in the last chapter.
This work studied different techniques to prepare particle containing phosphate glasses. Additionally, a process to sinter these glasses by hot uniaxial pressing was studied and developed. Our goal was to prepare to create transparent, particle containing glasses for photonic applications. So far, the challenges have been to prepare these glasses without significant agglomeration or corrosion of the particles during glass preparation. Erbium and ytterbium containing YAG nanoparticles and erbium containing 75 NaPO3 - 25 CaF2 (mol-%) glass-ceramic microparticles were mixed in with 90 NaPO3 - 10 NaF (mol-%) phosphate glass raw materials and already molten phosphate glass. In addition to YAG and glass ceramic particles, erbium and ytterbium doped NaYF4 particles were mixed with powdered glass and sintered into a solid glass. The effects of the sintering process on the particles were studied using commercial luminescent microparticles. Parameters for the sintering process were optimized to produce transparent glass successfully. The produced glass is clearly transparent, but has a brown coloration to it. The source of the coloration is presumed to be either nanoscale defects scattering shorter wavelengths of light or carbon contamination. Luminescent particles survived the sintering process unchanged according to our luminescence measurements and therefore we presume the process to be safe for other particles as well. YAG agglomerates were visible to the naked eye inside the glass when they were added in the glass batch. When added in the melt, the particles stayed on the top and did not diffuse inside the glass. According to emission measurements, the structure had changed in both cases. The glasses had an inhomogeneous distribution of particles and emission. The sintered glass had unchanged emission spectrum compared to the pure particles and a tenfold increase in emis-sion intensity relative to other methods of preparation. The resulting glass was not transparent due to particle agglomeration. Glass-ceramic particles did not survive the glass manufacturing or addition into the molten glass. Sintering glass-ceramic particles with the host glass produces a somewhat transparent glass, but with a narrower emission spectrum. NaYF4 particles containing glass was also transparent with an unchanged emission spectrum. The particles were agglomerated and the glass had crystallized at the glass-particle -interface.
The focus of paper is to asses and evaluate new utilisation method of coals combustion resides in glass manufacturing process. Mathematical model of glass manufacturing material balance was used to find favourable proportion of normally used batch materials and coal ash. It was found that possible to substitute up to 20 % of batch with coal ash. On the world glass production scale there is a potential to save 8,4 million tons of silica sand, 6 million tons of dolomite, 3 million tons of clay and 0,2 million tons of lime borate. Furthermore, potential to utilize 2 % of coal combustion products with suggested method.
The assembly and arrangement of microfibers have wide applications in biomedicine, material science, and microsystem. However, current micromanipulation methods for positioning and orientating individual microfibers are complex and hard to use. In this article, we report a novel self-alignment capillary gripper for microfiber manipulation that is facile and convenient. We determine the key parameters of the gripper including the required meniscus volume and the tip aspect ratio of the gripper through both numerical simulation and experimental investigation. A two-stage self-alignment process is employed to achieve high precision. The gripper can pick up and self-align microfibers with an aspect ratio of up to 300:1 at an accuracy of 2.1 ± 2.0 m and 0.6 ± 0.6 ° or better and create highly parallel linear arrays. The gripper is also versatile, where multiple types of microfibers including glass fibers, carbon fibers, dandelion seed fibers, and cat hairs can be picked up and self-aligned. Additionally, the gripper can construct two-dimensional patterns and plug a fiber into a microglass capillary.
Yksi tyypillisimmistä vauriomuodoista komposiittirakenteissa on delaminaatio, murtuma, joka saa alkunsa yksittäisten kuitulujitettujen kerrosten välissä, kun kerrokset irtoavat toisistaan. Delaminaatio voi aiheutua monesta tekijästä, mutta tässä diplomityössä pääpaino on delaminaatiolla, joka saa alkunsa kerrostenvälisestä leikkausvoimasta. Kerrostenvälinen leikkauslujuus (ILSS) on arvo, jota käytetään usein, kun halutaan vertailla erilaisia komposiitteja toisiinsa ja se käytännössä kertoo, kuinka hyvin komposiitti kykenee vastustamaan kerrostenvälistä leikkausvoimaa, ennen kuin se murtuu. Tämä diplomityö keskittyy ensisijaisesti ILSS-arvojen mittaamiseen sellaisilla laminaateilla, joissa kuitukerrokset eivät ole yhdensuuntaisia. Kokeellinen testaus suoritetaan ILSS:n mittaamiseen kehitetyn standardin, ASTM D2344, perusteella. Koekappaleina käytetään kahdenlaisia laminaatteja, joista ensimmäiset ovat lasikuitulujitettuja, toiset aramidilujitettuja. Testeissä käytetyissä lasikuitulujitetuissa laminaateissa on kahdenlaista laminointia, joita verrataan keskenään, jotta voidaan nähdä miten erilaiset kerrosjärjestykset vaikuttavat käyttäytymiseen ILSS-testeissä. Tarkempaa analyysia varten molemmista laminoinneista luotiin simulaatiomalli. Näin oli mahdollista selvittää, minkä kerrosten väliin leikkausjännityspiikit muodostuvat. Kokeelliset testit osoittivat, että useimmiten koekappaleet delaminoituivat alemmasta rajapinnasta, jossa lujitekuitujen suunta muuttuu. Tämä pystyttiin osoittamaan myös simulaatioilla, joissa alempaan rajapintaan muodostui suurimmat jännityspiikit. Laminaattien testaaminen kosteana ja korotetussa lämpötilassa heikensi ILSS-arvoja sekä ILSS-käyttäytymistä testeissä. Laminaattien ikäännyttäminen vesi-rikkihappo -upotuksessa ennen testaamista heikensi ILSS-arvoja, mutta ILSS käyttäytyminen pysyi hyvänä, ja laminaatit hajosivat delaminoitumalla. Simuloidut kriittiset leikkausjännitykset olivat 14- 24 % matalammat kuin ASTM standardin mukaan lasketut jännitykset. Simuloitu puhtaasti laminoinnista johtuva ero eri laminaattien välillä oli 34-58 % (riippuen reunaefektistä), mikä on suurempi kuin kokeissa havaittu ero (21-26 %).
The high density non-abelian matter produced in heavy ion collisions is extremely anisotropic. Prethermal dynamics for the anisotropic and weakly coupled matter is discussed. Thermalization is realized with the effective kinetic theory in the leading order accuracy of the weakly coupled expansion. With the initial condition from color glass condensate, hydrodynamization time for the LHC energies is realized to be about 1 fm/c, while the thermalization happens much later than the hydrodynamization.
The aim of this review is to illustrate how physical properties are important to food processing and quality. Three food products, flakes, porridge and bread, in addition to oat groats are used to show the influence of water and heat-treatments on the mechanical properties. The hydrothermal history of ingredients is shown to affect product quality. Water acts as a plasticiser and solvent in these foods, whilst heat modifies the conformation and interactions of macromolecular components. Structure as well as chemical composition is shown to govern texture.
This paper discusses craft and design practices through their impact on the environment. We consider how to act concerning the consequences of the craft and design industry. Also, we reflect on the agency of our field of practice in changing how we perceive the environment. We present three case studies of the European glass industry sites in Sweden, Italy and Finland, where we study contamination of the soil with participatory, speculative and craft methods. Through these cases, we reflect on our role in soil communities and ask how we may act in them with responsibility, hope and care. We conclude by proposing to act locally, to share our practices and make them visible, expanding our situated, personal skills and knowledge towards the political.
The Color Glass Condensate and its associated evolution equation, the JIMWLK equation have applications to many observables far beyond totally inclusive observables. The phenomenology is so rich that little has been done to explore beyond scaling behavior of correlators. We show first examples that exemplify the considerations necessary to access additional information both experimentally and theoretically and demonstrate that the Wilson line correlators appearing throughout make it imperative to consistently take into account that one is dealing with correlators of group elements and demonstrate how this imposes physical and phenomenological constraints. Similar considerations apply also to jet observables at finite Nc.
Glass fibre pipe winding automation can be based on trigonometry of rectangular triangle. Winding is done by rotating mould and moving it sideways at the same time. Purpose of simultaneous movement is spread the winded threads all over the mould. For a better quality all threads are meant to be placed next to each other. This can be done only if mould moves the exact length sideways while it rotates one round. The exact length is called rise. Rise is depending of wideness of thread bunch, winding angle and radius of mould. Different winding angles give different kind of firmness to pipe. Winding machine automation system includes electric drives, control device, HMI-device and measurement devices. Electric drives are often servomotors, because winding machine mechanics demand precision and speed. Measurements and control are used to make the quality of the winded pipe better. Understanding of Winding machine mechanics and winding process is vital to program solutions. Machine usability and user safety are important parts of program solutions.
The rheological characterization of glass-forming liquids is challenging due to their extreme temperature dependence and high stiffness at low temperatures. This study focuses on the special precautions that need to be taken to accommodate high sample stiffness and torsional instrument compliance in shear rheological experiments. The measurement errors due to the instrument compliance can be avoided by employing small-diameter parallel plate (SDPP) rheometry in combination of numerical instrument compliance corrections. Measurements of that type demonstrate that accurate and reliable rheological data can be obtained by SDPP rheometry despite unusually small diameter-to-gap (d/h) ratios. Specimen preparation for SDPP requires special attention, but then experiments show excellent repeatability. Advantages and some current applications of SDPP rheometry are briefly reviewed. SDPP rheometry is seen as a simple and versatile way to measure rheological properties of glass-forming liquids especially near their glass transition temperature.
The main goal of the thesis has been the preparation of a new optical battery made from glasses displaying green persistent luminescence (PeL) after being charged with infrared radiation. The base composition of the glasses was chosen from previous studies done by the Photonics Glasses Group in Tampere University. The novelty of this study was the use Ytterbium and Thulium, capable of absorbing infrared radiation and releasing visible light. Glasses were prepared using different techniques. In the first technique, the glasses were prepared using standard melting process. The work was divided into 3 steps; the first one dealt with the study and optimization of blue upconversion (UC) in glasses after irradiation at 975 nm. Glasses with different Yb3+/Tm3+ ratios were prepared using standard melting process. The second stage was meant to develop glass-ceramics from the most promising glasses to increase the intensity of the blue UC. Different heat-treatments were applied and the blue upconversion upon infrared excitation measured. Results lead to interesting conclusions. Indeed, although the blue upconversion was greatly enhanced in the lowest Yb concentrated glass, the blue emission intensity decreased after heat-treating the glasses prepared with >2 mol % of Yb2O3, most likely due to short distances between the Yb3+ ions, as was also reported in a similar research. The third step consisted on adding various wt % of commercial green persistence luminescent particles to the most promising samples. Lasting green emission was observed after infrared charging, confirming the energy transfer from Yb3+ to the upconverting Tm3+ ions and then to the persistent luminescent particles demonstrating that an optical battery could be obtained from the newly developed glasses. For the second technique, the blue upconversion from the glasses was obtained by adding NaYF4:Tm3+,Yb3+ nanocrystals and the PeL particles in the glass melt using the direct doping method. Some blue upconversion was observed but its intensity was probably too low to charge the PeL particles.
Metal nanoclusters, which exhibit extraordinary physical and chemical properties that are different from their bulk counterparts, are highly promising nanomaterials for photonics. Recently, the use of twophoton excitation to fabricate silver nanoclusters in polymers was reported but still lacks speed and flexibility which are imperative for applications such as labeling and spectroscopy. Here, we demonstrate the fabrication of fluorescent nanocluster microstructures using spatially phase-shaped laser beams. Using an incident power of 60 mW and exposure time of 8 s, we found that the smallest line-width of the fluorescent microstructures is 478 nm, which is comparable to the line-width achieved with a two-photon laser scanning approach. As a proof-of-principle demonstration, the technique is used to fabricate fluorescent micro-labels that could be used in anticounterfeiting applications.
A number of solid solutions based on BaFe12−xTixO19 M-type barium hexaferrite doped with titanium cations up to x = 2.00 were obtained using conventional ceramic technology. The phase composition, crystal structure and unit cell parameters were refined by the Rietveld method using powder X-ray diffraction data up to T = 900 K. It was found that all the compositions have a magnetoplumbite structure satisfactorily described by P63/mmc space group (No. 194). With increasing temperature and doping concentration, the unit cell parameters increase almost monotonically. The minimum volume of V ~ 696.72 Å3 was determined for the composition with x = 1.00 at T = 100 K, while the maximum value of V ~ 714.00 Å3 is observed for the composition with x = 2.00 at T = 900 K. The mechanism of occupation nonequivalent crystallographic positions with titanium cations is established. The spin-glass component of the magnetic phase state is fixed. The Tdif temperature of the difference between the ZFC-FC curves decreases with an increase in the concentration of titanium cations and the magnetic field from ~237.2 K to ~ 44.5 K, while the Tinf inflection temperature of the ZFC curve increases from ~21.0 K to ~23.8 K. With an increase in the doping concentration, both the Dav average and Dmax maximum clusters grow up to ~ 100 nm. As the magnetic field increases above the critical value, the spin-glass component disappears. For compositions with x > 1.00, the magnetization is not saturated in fields up to 6 T. Along with the formation of the spin-glass component, doping with titanium cations for barium hexaferrite lowers the TC Curie temperature down to T ~600 K. The Ms spontaneous and Mr remanent magnetizations, as well as the Bc coercivity, decrease with increasing doping concentration almost monotonically, while the latter has an inflection point at x = 1.00. The minimum values of spontaneous and remanent magnetization, as well as coercivity, are observed for the composition with x = 2.00 and amount to Ms ~17.7 emu/g, Mr ~1.9 emu/g, and Bc ~3.9 × 10−3 T, respectively. An interpretation of the magnetic state of the doped BaFe12−xTixO19 barium hexaferrite is given taking into account the mechanism of occupation nonequivalent crystallographic positions with titanium cations.
Understanding interfacial interactions in polymer systems is crucial for their applicability for instance in adhesives and coatings. Enclosing polymers in a cylindrical volume provides a system for studying interactions dictated by a continuous interfacial layer and a bulk-like volume in the middle of the cylinders. Here, we describe a simple method for enclosing polymers into boron nitride nanotubes (BNNTs) and establishing the effect of the interfacial interactions on the glass transition temperature (Tg) of the polymers by infrared spectroscopy. The volume of the inner channel is large in comparison to the volume of the loaded polymer coils, allowing the polymer to expand along the inner channel, resulting in the effect of interfacial interactions on polymer dynamics dominating over confinement effects. As examples, we loaded poly(4-vinyl pyridine), poly(methyl methacrylate), poly(vinyl pyrrolidone), and poly(disperse red 1 acrylate) in BNNTs. The strongest interaction between the studied polymer and BNNTswas observed for poly(4-vinyl pyridine), which also caused a significant increase of Tg. In addition to characterizing the effect of interfacial interactions on the thermal transitions of the polymers, this method, which is generalizable to most soluble polymer materials, can be used for studying photoinduced transitions in photoactive polymers thanks to the transparency of the BNNTs at visible wavelengths.
Fiber-reinforced composite as oral implant material: Experimental studies of glass fiber and bioactive glass in vitro and in vivo Department of Prosthetic Dentistry and Biomaterials Science, Institute of Dentistry, University of Turku, Turku, Finland 2008. Biocompatibility and mechanical properties are important variables that need to be determined when new materials are considered for medical implants. Special emphasis was placed on these characteristics in the present work, which aimed to investigate the potential of fiber-reinforced composite (FRC) material as an oral implant. Furthermore, the purpose of this study was to explore the effect of bioactive glass (BAG) on osseointegration of FRC implants. The biocompatibility and mechanical properties of FRC implants were studied both in vitro and in vivo. The mechanical properties of the bulk FRC implant were tested with a cantilever bending test, torsional test and push-out test. The biocompatibility was first evaluated with osteoblast cells cultured on FRC substrates. Bone bonding was determined with the mechanical push-out test and histological as well as histomorplanimetric evaluation. Implant surface was characterized with SEM and EDS analysis. The results of these studies showed that FRC implants can withstand the static load values comparably to titanium. Threaded FRC implants had significantly higher push-out strength than the threaded titanium implants. Cell culture study revealed no cytotoxic effect of FRC materials on the osteoblast-like-cells. Addition of BAG particles enhanced cell proliferation and mineralization of the FRC substrates The in vivo study showed that FRC implants can withstand static loading until failure without fracture. The results also suggest that the FRC implant is biocompatible in bone. The biological behavior of FRC was comparable to that of titanium after 4 and 12 weeks of implantation. Furthermore, addition of BAG to FRC implant increases peri-implant osteogenesis and bone maturation.
Abstract In the first part of the thesis, novel glass-ceramic compositions based on Al2O3 and BaTiO3 and bismuth-zinc borosilicate (BBSZ) glass, sintered at ultra-low temperatures, were researched. With adequate glass concentration, dense microstructures and useful dielectric properties were achieved. The composite of BaTiO3 with 70 wt % BBSZ sintered at 450 °C exhibited the highest relative permittivity, εr, of 132 and 207 at 100 kHz and 100 MHz, respectively. Thus, the dielectric properties of the composites were dominated by the characteristics of glass, BaTiO3, and Bi24Si2O40phase, especially the contribution of Bi24Si2O40 for the samples with 70–90 wt % glass. Actually, the existence of the secondary phase Bi24Si2O40 may not hinder but enhance the dielectric properties. The Al2O3-BBSZ composition samples showed a similar situation, not only for densification but also for their microstructures and phases (Al2O3, BBSZ, Bi24Si2O40), explaining the achieved dielectric properties. The second part of the thesis mainly discusses the composite of BaTiO3 with 50 wt % BBSZ with different thermal treatments. After sintering at 720 °C, dense microstructures and the existence of Bi4BaTi4O15, BaTiO3, Bi24Si2O40 phases were observed. The results also showed that the size of glass powder particles did not influence the dielectric properties (εr = 263–267, tan δ = 0.013 at 100 kHz) of sintered samples, but the addition of LiF degraded the dielectric properties due to the features and amount of Bi4BaTi4O15. These results demonstrate the feasibility of the BBSZ based composites for higher sintering temperature technologies as well. At the end, a novel binder system, which enables low sintering temperatures close to 300 °C, was developed. A dielectric multilayer module containing BaTiO3-BBSZ and Al2O3-BBSZ composites with silver electrodes was co-fired at 450 °C without observable cracks and diffusions. These results indicate that these glass-ceramic composites provide a new horizon to fabricate environmentally friendly ULTCC materials, as well as multilayers for multimaterial 3D electronics packages and high frequency devices.
Experimental processes that are sensitive to parton Wigner distributions provide a powerful tool to advance our understanding of proton structure. In this work, we compute gluon Wigner and Husimi distributions of protons within the color glass condensate framework, which includes a spatially dependent McLerranVenugopalan initial configuration and the explicit numerical solution of the Jalilian-Marian–Iancu– McLerran–Weigert–Leonidov–Kovner equations. We determine the leading anisotropy of the Wigner and Husimi distributions as a function of the angle between the impact parameter and transverse momentum. We study experimental signatures of these angular correlations at a proposed electron-ion collider by computing coherent diffractive dijet production cross sections in e þ p collisions within the same framework. Specifically, we predict the elliptic modulation of the cross section as a function of the relative angle between the nucleon recoil and dijet transverse momentum for a wide kinematical range.We further predict its dependence on the collision energy, which is dominated by the growth of the proton with decreasing x.
In the literature part of this thesis the human olfactory sense is explored. Also, individual differences in the sense of smell are studied. Since the study focuses on whiskey the anesthetic effects of ethanol on the olfactory system are explored. The different drinking vessels commonly used with whiskey are introduced and reviewed. A novel whiskey glass was studied for its aroma enhancing effects. The glass was designed to lessen the effect of ethanol anesthesia while nosing a whiskey from the glass. A method for headspace solid-phase microextraction (HS-SPME) was developed which adsorbed volatile compounds from the whiskey glass. The HS-SPME method developed was used to analyze whiskey volatile aroma-active compounds. The compounds were identified and quantitated using gas chromatography-flame-ionization detector (GC-FID). For comparison a whiskey sample is quantitated by direct injection and analyzed using gas chromatography-mass spectrometry (GC-MS). Ethanol evaporation experiments were conducted to verify the working principle of the novel whiskey glass. Gas chromatography-olfactometry (GC-O) was used to recognize that the aroma-active compounds of whiskey extracted from the novel glass can be perceived. The HS-SPME method from the whiskey glass was developed to simulate the natural whiskey nosing conditions to ensure relevant results. Several matters regarding the HS-SPME method were considered. These included duration, timing, closed or open headspace and temperature. With the developed method whiskey odorants known to be in the whiskey sample could be identified. Quantitation of these odorants was more challenging and subsequent analyses showed variation in quantities. GC-O also did not perfectly correlate with quantitation’s indicating that some odor-active compounds were under the detection limit.