21 resultados para focal and segmental glomerulosclerosis

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


Relevância:

40.00% 40.00%

Publicador:

Resumo:

The Repair of segmental defects in load-bearing long bones is a challenging task because of the diversity of the load affecting the area; axial, bending, shearing and torsional forces all come together to test the stability/integrity of the bone. The natural biomechanical requirements for bone restorative materials include strength to withstand heavy loads, and adaptivity to conform into a biological environment without disturbing or damaging it. Fiber-reinforced composite (FRC) materials have shown promise, as metals and ceramics have been too rigid, and polymers alone are lacking in strength which is needed for restoration. The versatility of the fiber-reinforced composites also allows tailoring of the composite to meet the multitude of bone properties in the skeleton. The attachment and incorporation of a bone substitute to bone has been advanced by different surface modification methods. Most often this is achieved by the creation of surface texture, which allows bone growth, onto the substitute, creating a mechanical interlocking. Another method is to alter the chemical properties of the surface to create bonding with the bone – for example with a hydroxyapatite (HA) or a bioactive glass (BG) coating. A novel fiber-reinforced composite implant material with a porous surface was developed for bone substitution purposes in load-bearing applications. The material’s biomechanical properties were tailored with unidirectional fiber reinforcement to match the strength of cortical bone. To advance bone growth onto the material, an optimal surface porosity was created by a dissolution process, and an addition of bioactive glass to the material was explored. The effects of dissolution and orientation of the fiber reinforcement were also evaluated for bone-bonding purposes. The Biological response to the implant material was evaluated in a cell culture study to assure the safety of the materials combined. To test the material’s properties in a clinical setting, an animal model was used. A critical-size bone defect in a rabbit’s tibia was used to test the material in a load-bearing application, with short- and long-term follow-up, and a histological evaluation of the incorporation to the host bone. The biomechanical results of the study showed that the material is durable and the tailoring of the properties can be reproduced reliably. The Biological response - ex vivo - to the created surface structure favours the attachment and growth of bone cells, with the additional benefit of bioactive glass appearing on the surface. No toxic reactions to possible agents leaching from the material could be detected in the cell culture study when compared to a nontoxic control material. The mechanical interlocking was enhanced - as expected - with the porosity, whereas the reinforcing fibers protruding from the surface of the implant gave additional strength when tested in a bone-bonding model. Animal experiments verified that the material is capable of withstanding load-bearing conditions in prolonged use without breaking of the material or creating stress shielding effects to the host bone. A Histological examination verified the enhanced incorporation to host bone with an abundance of bone growth onto and over the material. This was achieved with minimal tissue reactions to a foreign body. An FRC implant with surface porosity displays potential in the field of reconstructive surgery, especially regarding large bone defects with high demands on strength and shape retention in load-bearing areas or flat bones such as facial / cranial bones. The benefits of modifying the strength of the material and adjusting the surface properties with fiber reinforcement and bone-bonding additives to meet the requirements of different bone qualities are still to be fully discovered.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Feature extraction is the part of pattern recognition, where the sensor data is transformed into a more suitable form for the machine to interpret. The purpose of this step is also to reduce the amount of information passed to the next stages of the system, and to preserve the essential information in the view of discriminating the data into different classes. For instance, in the case of image analysis the actual image intensities are vulnerable to various environmental effects, such as lighting changes and the feature extraction can be used as means for detecting features, which are invariant to certain types of illumination changes. Finally, classification tries to make decisions based on the previously transformed data. The main focus of this thesis is on developing new methods for the embedded feature extraction based on local non-parametric image descriptors. Also, feature analysis is carried out for the selected image features. Low-level Local Binary Pattern (LBP) based features are in a main role in the analysis. In the embedded domain, the pattern recognition system must usually meet strict performance constraints, such as high speed, compact size and low power consumption. The characteristics of the final system can be seen as a trade-off between these metrics, which is largely affected by the decisions made during the implementation phase. The implementation alternatives of the LBP based feature extraction are explored in the embedded domain in the context of focal-plane vision processors. In particular, the thesis demonstrates the LBP extraction with MIPA4k massively parallel focal-plane processor IC. Also higher level processing is incorporated to this framework, by means of a framework for implementing a single chip face recognition system. Furthermore, a new method for determining optical flow based on LBPs, designed in particular to the embedded domain is presented. Inspired by some of the principles observed through the feature analysis of the Local Binary Patterns, an extension to the well known non-parametric rank transform is proposed, and its performance is evaluated in face recognition experiments with a standard dataset. Finally, an a priori model where the LBPs are seen as combinations of n-tuples is also presented

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The purpose of this thesis is to reveal how the laser cutting parameters influence lasercutting of particleboard, HDF and MDF. The literature review introduces the basic principle of CO2 laser, CO2 laser equipment and its usage in cutting of wood-based materials. The experimental part focuses on the discussion and analysis ofthe test data and attempts to draw conclusions on the influence of various parameters, including laser power, focal length of the lens and cutting gas, on the cutting speed and kerf quality. The tested materials include various thicknesses of particleboard, HDF and MDF samples. A TRUMPF TLF2700 HQ laser equipment was used for the experiments. To obtain valid data, the test samples must be completely cut through without any bonding of wood fibre. The maximum cutting speed is linear dependent on the laser power in thecondition that the other parameters are constant. For each thickness of a specific material type, there is a minimum laser power for cutting. Normally, the topand bottom kerf widths increase with the enhancement of laser power. There may be a critical laser power which can generate the minimum cross-sectional kerf width. Lens of larger focal length may achieve higher cutting speed. As the focal length becomes larger, the top kerf width tends to increase while the bottom andcross-sectional kerf widths to the opposite. Of all cutting gases, oxygen can help achieve higher cutting speed. The gas pressure of nitrogen does not seem to have strong influence on the cutting result. Generally, 2 bar air is more preferable for higher cutting speed. For particleboard and MDF samples of larger thickness than 12 mm, 2 bar argon can be used to reach remarkably higher cutting speed than the 5 bar. Generally, the 190.5 mm lens can produce smallest total kerf width. The kerf sides of thicker samples are darker than the thinner ones. The sample darkness tends to be lower as laser power increased. 63.5 mm lens seemed tocause more darkness than other lens. 5 bar cutting gases can produce less dark side kerfs than 2 bar ones. Oxygen normally causes darker kerfs than other gases. No distinct differences were found between nitrogen and argon.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

There is a broad consensus among economists that technologicalchange has been a major contributor to the productivity growth and, hence, to the growth of the material welfare in western industrialized countries at least over the last century. Paradoxically, this issue has not been the focal point of theoretical economics. At the same time, we have witnessed the rise of the importance of technological issues at the strategic management level of business firms. Interestingly, the research has not accurately responded to this challenge either. The tension between the overwhelming empirical evidence of the importance of technology and its relative omission in the research offers a challenging target for a methodological endeavor. This study deals with the question of how different theories cope with technology and explain technological change. The focusis at the firm level and the analysis concentrates on metatheoretical issues, except for the last two chapters, which examine the problems of strategic management of technology. Here the aim is to build a new evolutionary-based theoreticalframework to analyze innovation processes at the firm level. The study consistsof ten chapters. Chapter 1 poses the research problem and contrasts the two basic approaches, neoclassical and evolutionary, to be analyzed. Chapter 2 introduces the methodological framework which is based on the methodology of isolation. Methodological and ontoogical commitments of the rival approaches are revealed and basic questions concerning their ways of theorizing are elaborated. Chapters 3-6 deal with the so-called substantive isolative criteria. The aim is to examine how different approaches cope with such critical issues as inherent uncertainty and complexity of innovative activities (cognitive isolations, chapter 3), theboundedness of rationality of innovating agents (behavioral isolations, chapter4), the multidimensional nature of technology (chapter 5), and governance costsrelated to technology (chapter 6). Chapters 7 and 8 put all these things together and look at the explanatory structures used by the neoclassical and evolutionary approaches in the light of substantive isolations. The last two cpahters of the study utilize the methodological framework and tools to appraise different economics-based candidates in the context of strategic management of technology. The aim is to analyze how different approaches answer the fundamental question: How can firms gain competitive advantages through innovations and how can the rents appropriated from successful innovations be sustained? The last chapter introduces a new evolutionary-based technology management framework. Also the largely omitted issues of entrepreneurship are examined.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Tiedon jakaminen ja kommunikointi ovat tärkeitä toimintoja verkostoituneiden yritysten välillä ja ne käsitetäänkin yhteistyösuhteen yhtenä menestystekijänä ja kulmakivenä. Tiedon jakamiseen liittyviä haasteita ovat mm. yrityksen liiketoiminnalle kriittisen tiedon vuotaminen ja liiketoiminnan vaatima tiedon reaaliaikaisuus ja riittävä määrä. Tuotekehitysyhteistyössä haasteellista on tiedon jäsentymättömyys ja sitä kautta lisääntyvä tiedon jakamisen tarve, minkä lisäksi jaettava tieto on usein monimutkaista ja yksityiskohtaista. Lisäksi tuotteiden elinkaaret lyhenevät, ja ulkoistaminen ja yhteistyö ovat yhä kasvavia trendejä liiketoiminnassa. Yhdessä nämä tekijät johtavat siihen, että tiedon jakaminen on haastavaa eritoten verkostoituneiden yritysten välillä. Tässä tutkimuksessa tiedon jakamisen haasteisiin pyrittiin vastaamaan ottamalla lähtökohdaksi tiedon jakamisen tilanneriippuvuuden ymmärtäminen. Työssä vastattiin kahteen pääkysymykseen: Mikä on tiedon jakamisen tilanneriippuvuus ja miten sitä voidaan hallita? Tilanneriippuvuudella tarkoitetaan työssä niitä tekijöitä, jotka vaikuttavat siihen, miten yritys jakaa tietoa tuotekehityskumppaneidensa kanssa. Tiedon jakamisella puolestaan tarkoitetaan yrityksestä toiselle siirrettävää tietoa, jota tarvitaan tuotekehitysprojektin aikana. Työn empiirinen aineisto on kerätty laadullisella tutkimusotteella case- eli tapaustutkimuksena yhdessä telekommunikaatioalan yrityksessä jasen eri liiketoimintayksiköissä. Tutkimusjoukko käsitti 19 tuotekehitys- ja toimittajanhallintatehtävissä toimivaa johtajaa tai päällikköä. Työ nojaa pääasiassa hankintojen johtamisen tutkimuskenttään ja tilanneriippuvuuden selvittämiseksi paneuduttiin erityisesti verkostojen tutkimukseen. Työssä kuvattiin tiedon jakaminen yhtenä verkoston toimintona ja yhteistyöhön liittyvättiedon jakamisen hyödyt, haasteet ja riskit identifioitiin. Tämän lisäksi työssä kehitettiin verkoston tutkimismalleja ja yhdistettiin eri tasoilla tapahtuvaa verkoston tutkimusta. Työssä esitettiin malli verkoston toimintojen tutkimiseksija todettiin, että verkostotutkimusta pitäisi tehdä verkosto, ketju, yrityssuhde- ja yritystasolla. Malliin on myös hyvä yhdistää tuote- ja tehtäväkohtaiset ominaispiirteet. Kirjallisuuskatsauksen perusteella huomattiin, että tiedon jakamista on aiemmin tarkasteltu lähinnä tuote- ja yrityssuhteiden tasolla. Väitöskirjassa esitettiin lisää merkittäviä tekijöitä, jotka vaikuttavat tiedon jakamiseen. Näitä olivat mm. tuotekehitystehtävän luonne, teknologia-alueen kypsyys ja toimittajan kyvykkyys. Tiedon jakamisen luonnetta tarkasteltaessa erotettiin operatiivinen, projektin hallintaan ja tuotekehitykseen liittyvä tieto sekä yleinen, toimittajan hallintaan liittyvä strateginen tieto. Tulosten mukaan erityisesti tuotekehityksen määrittelyvaihe ja tapaamiset kasvotusten korostuivat yhteistyössä. Empirian avulla tutkittiin myös niitä tekijöitä, joilla tiedon jakamista voidaan hallita tilanneriippuvuuteen perustuen, koska aiemmin tiedon jakamisen hallintakeinoja tai menestystekijöitä ei ole liitetty suoranaisesti eri olosuhteisiin. Nämä hallintakeinot jaettiin yhteistyötason- ja tuotekehitysprojektitason tekijöihin. Yksi työn keskeisistä tuloksista on se, että huolimatta tiedon jakamisen haasteista, monet niistä voidaan eliminoida tunnistamalla vallitsevat olosuhteet ja panostamalla tiedon jakamisen hallintakeinoihin. Työn manageriaalinen hyöty koskee erityisesti yrityksiä, jotka suunnittelevat ja tekevät tuotekehitysyhteistyötä yrityskumppaniensa kanssa. Työssä esitellään keinoja tämän haasteellisen tehtäväkentän hallintaan ja todetaan, että yritysten pitäisikin kiinnittää entistä enemmän huomiota tiedon jakamisen ja kommunikaation hallintaan jo tuotekehitysyhteistyötä suunniteltaessa.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This dissertation considers the segmental durations of speech from the viewpoint of speech technology, especially speech synthesis. The idea is that better models of segmental durations lead to higher naturalness and better intelligibility. These features are the key factors for better usability and generality of synthesized speech technology. Even though the studies are based on a Finnish corpus the approaches apply to all other languages as well. This is possibly due to the fact that most of the studies included in this dissertation are about universal effects taking place on utterance boundaries. Also the methods invented and used here are suitable for any other study of another language. This study is based on two corpora of news reading speech and sentences read aloud. The other corpus is read aloud by a 39-year-old male, whilst the other consists of several speakers in various situations. The use of two corpora is twofold: it involves a comparison of the corpora and a broader view on the matters of interest. The dissertation begins with an overview to the phonemes and the quantity system in the Finnish language. Especially, we are covering the intrinsic durations of phonemes and phoneme categories, as well as the difference of duration between short and long phonemes. The phoneme categories are presented to facilitate the problem of variability of speech segments. In this dissertation we cover the boundary-adjacent effects on segmental durations. In initial positions of utterances we find that there seems to be initial shortening in Finnish, but the result depends on the level of detail and on the individual phoneme. On the phoneme level we find that the shortening or lengthening only affects the very first ones at the beginning of an utterance. However, on average, the effect seems to shorten the whole first word on the word level. We establish the effect of final lengthening in Finnish. The effect in Finnish has been an open question for a long time, whilst Finnish has been the last missing piece for it to be a universal phenomenon. Final lengthening is studied from various angles and it is also shown that it is not a mere effect of prominence or an effect of speech corpus with high inter- and intra-speaker variation. The effect of final lengthening seems to extend from the final to the penultimate word. On a phoneme level it reaches a much wider area than the initial effect. We also present a normalization method suitable for corpus studies on segmental durations. The method uses an utterance-level normalization approach to capture the pattern of segmental durations within each utterance. This prevents the impact of various problematic variations within the corpora. The normalization is used in a study on final lengthening to show that the results on the effect are not caused by variation in the material. The dissertation shows an implementation and prowess of speech synthesis on a mobile platform. We find that the rule-based method of speech synthesis is a real-time software solution, but the signal generation process slows down the system beyond real time. Future aspects of speech synthesis on limited platforms are discussed. The dissertation considers ethical issues on the development of speech technology. The main focus is on the development of speech synthesis with high naturalness, but the problems and solutions are applicable to any other speech technology approaches.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The purpose of this study was to investigate the nature of co-operation between a project owner and an outside engineering consultant in combined heat and power plant implementation projects. Moreover, as another focal subject of the study was to familiarize the purchasing behavior of the energy producer and how an outside engineering consultant participated into different stages of the purchasing process. The study was carried out as a multiple case study including altogether six Finnish power plant implementation projects that had been taken into commercial use during 1995 – 2015. By adjusting the findings of empirical interview data and comparing those to the theoretical framework concerning, among others, Finnish energy production, engineering consulting businesses, delivery methods of construction project and finally the purchasing process, it can be concluded that especially in the power plant implementation projects in the past have a great influence to decisions made during the project. The role of the main engineering consultant is to act as an assistant, who helps to achieve the project goals successfully rather than an advisor who only knows how the project should be conducted. At least in these five project cases this was the case, meaning that the final decision power always remaining with project owner.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Collaboration between competing firms (coopetition) has emerged as an important issue forn business practice in many industries. Extant literature has examined coopetition on many levels of analysis, but lacks clarity in distinguishing it explicitly from cooperation between noncompeting organizations. Because of this, the performance implications of coopetition from the perspective of an individual firm are still ambiguous – some research suggests positive results whereas other studies suggest detrimental outcomes. The aim in this dissertation is to narrow these gaps by exploring how firms create and appropriate value through collaboration with their competitors. The dissertation is divided into two parts. The first part comprises an overview of the relevant literature, as well as the conclusions of the whole study, and the second part includes six research publications. Both qualitative and quantitative methodologies are utilized. The results suggest that coopetition embodies the distinctive logic of value creation and appropriation from the perspective of an individual firm, and thus differs in terms of performance implications from cooperation between non-competitors. The distinction comes from the fact that competitors have somewhat similar understanding, capabilities and interest related to certain markets, which is potentially both challenging and beneficial in terms of the individual firm’s competitiveness. It appears from the findings that there are distinctive firm-external and firm-specific factors affecting the success of a coopetition strategy. This study makes three main contributions. First, on the conceptual level it shows the distinction between coopetition and cooperation between non-rivals as a collaborative inter-organizational relationship. Secondly, it sets out a framework and propositions that enhance understanding of how value is created and appropriated in coopetition from the perspective of an individual firm. Thirdly, it offers empirical evidence of how coopetition affects firms’ innovation and market performance, and identifies the focal internal and external factors involved. In general terms, the thesis adds to our knowledge of how a firm can successfully utilize a coopetition strategy in its pursuit of improved performance.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Metastatic bone lesions are commonly associated with prostate cancer affecting approximately 60-80% of the patients. The progression of prostate cancer into an advanced stage is a complex process and its molecular mechanisms are poorly understood. So far, no curative treatment is available for advanced stages of prostate cancer. Bisphosphonates (BPs) are synthetic pyrophosphate analogues, which are used as therapeutics for various metabolic bone diseases because of their ability to inhibit osteoclastic bone resorption. Nitrogen-containing bisphosphonates block the function of osteoclasts by disturbing the vesicular traffic and the mevalonate pathway -related enzymes, for example farnesyl diphosphate synthase, which is involved in post-translational isoprenylation of small GTPases. In addition, the anti-proliferative, anti-invasive and pro-apoptotic effects of nitrogen-containing bisphosphonates on various cancer cell lines have been reported. The aim of this thesis work was to clarify the effects of bisphosphonates on prostate cancer cells, focusing on the mechanisms of adhesion, invasion and migration. Furthermore, the role of the mevalonate pathway and prenylation reactions in invasion and regulation of the cytoskeleton of prostate cancer cells were examined. Finally, the effects of alendronate on cytoskeleton- and actin-related proteins in prostate cancer cells were studied in vitro and in vivo. The results showed that the nitrogen-containing bisphosphonate alendronate inhibited the adhesion of prostate cancer cells to various extracellular matrix proteins and migration and invasion in vitro. Inhibition of invasion and migration was reversed by mevalonate pathway intermediates. The blockage of the prenylation transferases GGTase I and FTase inhibited the invasion, migration and actin organization of prostate cancer cells. The marked decrease of cofilin was observed by the prenylation inhibitors used. Inhibition of GGTase I also disrupted the regulation of focal adhesion kinase and paxillin. In addition, alendronate disrupted the cytoskeletal organization and decreased the level of cofilin in vitro and in vivo. The decrease of the cofilin level by alendronate could be one of the key mechanisms behind the observed inhibition of migration and invasion. Based on the effects of nitrogen-containing bisphosphonates on tumor cell invasion and cytoskeletal organization, they can be suggested to be developed as therapeutics for inhibiting prostate cancer metastasis.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The main objective of this Master’s Thesis was to examine the interrelations of service quality and relationship quality (customer satisfaction, trust and commitment), and find out are they antecedents for customer loyalty in business-to-business context. Literature review revealed some research gaps concerning these focal concepts, which should be studied more closely. The theoretical basis for this research was collected for evaluating a strategic increase of customer’s perceptions of service quality and relationship quality as well as customer loyalty in business-to-business environment, and it was tested empirically in a sample of 164 corporate customers, who responded to the Internet-based survey. The measures, used in the survey, were first assessed by using confirmatory factor analysis (CFA), and then the hypothesized relationships were further verified using structural equation modeling (SEM) in LISREL 8.80. There was found support for a half of the hypothesized construct relations. The results of the research confirm the direct influence of trust and commitment on customer loyalty. Also, service quality turned out to have an indirect impact on customer loyalty through trust. No support, however, was offered for the proposed impact of customer satisfaction on loyalty in this case. The research provides managerially relevant and actionable results that may help service providers execute more specific customer relationship quality strategies that lead to higher customer loyalty.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

It is known already from 1970´s that laser beam is suitable for processing paper materials. In this thesis, term paper materials mean all wood-fibre based materials, like dried pulp, copy paper, newspaper, cardboard, corrugated board, tissue paper etc. Accordingly, laser processing in this thesis means all laser treatments resulting material removal, like cutting, partial cutting, marking, creasing, perforation etc. that can be used to process paper materials. Laser technology provides many advantages for processing of paper materials: non-contact method, freedom of processing geometry, reliable technology for non-stop production etc. Especially packaging industry is very promising area for laser processing applications. However, there are only few industrial laser processing applications worldwide even in beginning of 2010´s. One reason for small-scale use of lasers in paper material manufacturing is that there is a shortage of published research and scientific articles. Another problem, restraining the use of laser for processing of paper materials, is colouration of paper material i.e. the yellowish and/or greyish colour of cut edge appearing during cutting or after cutting. These are the main reasons for selecting the topic of this thesis to concern characterization of interaction of laser beam and paper materials. This study was carried out in Laboratory of Laser Processing at Lappeenranta University of Technology (Finland). Laser equipment used in this study was TRUMPF TLF 2700 carbon dioxide laser that produces a beam with wavelength of 10.6 μm with power range of 190-2500 W (laser power on work piece). Study of laser beam and paper material interaction was carried out by treating dried kraft pulp (grammage of 67 g m-2) with different laser power levels, focal plane postion settings and interaction times. Interaction between laser beam and dried kraft pulp was detected with different monitoring devices, i.e. spectrometer, pyrometer and active illumination imaging system. This way it was possible to create an input and output parameter diagram and to study the effects of input and output parameters in this thesis. When interaction phenomena are understood also process development can be carried out and even new innovations developed. Fulfilling the lack of information on interaction phenomena can assist in the way of lasers for wider use of technology in paper making and converting industry. It was concluded in this thesis that interaction of laser beam and paper material has two mechanisms that are dependent on focal plane position range. Assumed interaction mechanism B appears in range of average focal plane position of 3.4 mm and 2.4 mm and assumed interaction mechanism A in range of average focal plane position of 0.4 mm and -0.6 mm both in used experimental set up. Focal plane position 1.4 mm represents midzone of these two mechanisms. Holes during laser beam and paper material interaction are formed gradually: first small hole is formed to interaction area in the centre of laser beam cross-section and after that, as function of interaction time, hole expands, until interaction between laser beam and dried kraft pulp is ended. By the image analysis it can be seen that in beginning of laser beam and dried kraft pulp material interaction small holes off very good quality are formed. It is obvious that black colour and heat affected zone appear as function of interaction time. This reveals that there still are different interaction phases within interaction mechanisms A and B. These interaction phases appear as function of time and also as function of peak intensity of laser beam. Limit peak intensity is the value that divides interaction mechanism A and B from one-phase interaction into dual-phase interaction. So all peak intensity values under limit peak intensity belong to MAOM (interaction mechanism A one-phase mode) or to MBOM (interaction mechanism B onephase mode) and values over that belong to MADM (interaction mechanism A dual-phase mode) or to MBDM (interaction mechanism B dual-phase mode). Decomposition process of cellulose is evolution of hydrocarbons when temperature is between 380- 500°C. This means that long cellulose molecule is split into smaller volatile hydrocarbons in this temperature range. As temperature increases, decomposition process of cellulose molecule changes. In range of 700-900°C, cellulose molecule is mainly decomposed into H2 gas; this is why this range is called evolution of hydrogen. Interaction in this range starts (as in range of MAOM and MBOM), when a small good quality hole is formed. This is due to “direct evaporation” of pulp via decomposition process of evolution of hydrogen. And this can be seen can be seen in spectrometer as high intensity peak of yellow light (in range of 588-589 nm) which refers to temperature of ~1750ºC. Pyrometer does not detect this high intensity peak since it is not able to detect physical phase change from solid kraft pulp to gaseous compounds. As interaction time between laser beam and dried kraft pulp continues, hypothesis is that three auto ignition processes occurs. Auto ignition of substance is the lowest temperature in which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark. Three auto ignition processes appears in range of MADM and MBDM, namely: 1. temperature of auto ignition of hydrogen atom (H2) is 500ºC, 2. temperature of auto ignition of carbon monoxide molecule (CO) is 609ºC and 3. temperature of auto ignition of carbon atom (C) is 700ºC. These three auto ignition processes leads to formation of plasma plume which has strong emission of radiation in range of visible light. Formation of this plasma plume can be seen as increase of intensity in wavelength range of ~475-652 nm. Pyrometer shows maximum temperature just after this ignition. This plasma plume is assumed to scatter laser beam so that it interacts with larger area of dried kraft pulp than what is actual area of beam cross-section. This assumed scattering reduces also peak intensity. So result shows that assumably scattered light with low peak intensity is interacting with large area of hole edges and due to low peak intensity this interaction happens in low temperature. So interaction between laser beam and dried kraft pulp turns from evolution of hydrogen to evolution of hydrocarbons. This leads to black colour of hole edges.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This Thesis discusses the phenomenology of the dynamics of open quantum systems marked by non-Markovian memory effects. Non-Markovian open quantum systems are the focal point of a flurry of recent research aiming to answer, e.g., the following questions: What is the characteristic trait of non-Markovian dynamical processes that discriminates it from forgetful Markovian dynamics? What is the microscopic origin of memory in quantum dynamics, and how can it be controlled? Does the existence of memory effects open new avenues and enable accomplishments that cannot be achieved with Markovian processes? These questions are addressed in the publications forming the core of this Thesis with case studies of both prototypical and more exotic models of open quantum systems. In the first part of the Thesis several ways of characterizing and quantifying non-Markovian phenomena are introduced. Their differences are then explored using a driven, dissipative qubit model. The second part of the Thesis focuses on the dynamics of a purely dephasing qubit model, which is used to unveil the origin of non-Markovianity for a wide class of dynamical models. The emergence of memory is shown to be strongly intertwined with the structure of the spectral density function, as further demonstrated in a physical realization of the dephasing model using ultracold quantum gases. Finally, as an application of memory effects, it is shown that non- Markovian dynamical processes facilitate a novel phenomenon of timeinvariant discord, where the total quantum correlations of a system are frozen to their initial value. Non-Markovianity can also be exploited in the detection of phase transitions using quantum information probes, as shown using the physically interesting models of the Ising chain in a transverse field and a Coulomb chain undergoing a structural phase transition.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The rapid economic growth in China has resulted in environmental challenges ranging from air pollution to water-related issues. Thus supporting clean technology, or cleantech, that encompasses industries that focus on alternative energy, pollution and recycling, power supplies and conservation has become one of the focal points in the Chinese economic policy for the next decade. Simultaneously, the Finnish government has initiated programs to support the internationalisation of domestic cleantech companies in an attempt to spiral the industry into one of the pillars of Finnish economic growth. This study concentrates on the conjunction of these two themes and studies the challenges faced by Finnish cleantech SMEs in the Chinese market. Consequently, the study answers the following sub questions: 1. What human and financial resource-based challenges do Finnish cleantech SMEs face in the Chinese market and what are their solutions? 2. What knowledge-based challenges do Finnish cleantech SMEs face in the Chinese market and how can these difficulties be resolved? 3. What network-based challenges do Finnish cleantech SMEs face in the Chinese market, how do they relate to the resource- and knowledge-based challenges, and how can these difficulties be resolved? This qualitative study is conducted by analysing four semi structured interviews collected from four Finnish SMEs that operate in China. The findings of the study indicate that in human resources the most important challenges are related to the hiring and retaining of employees. In contrast to extant academic literature results distinguish salary and social status as the main solutions to this challenge. Regarding financial resources it is discovered that cleantech companies enjoy a benign business environment in China and benefit from the Chinese government’s support for cleantech industry. Challenges related to knowledge resources can be grouped into categories with the most interesting knowledge flows being the stream of local market knowledge into to the foreign parent company and the outward flow of manufacturing and business practice information into the target venture. The challenge related to the first flow is gathering relevant information and the main solutions are clustering at the foreign location and hiring knowledge prior to internationalisation. Regarding the second flow the main challenge is related to intellectual property rights and the most interesting solution is the purposeful transformation of explicit knowledge into tacit knowledge. Finally, it is discovered that networks, called guanxi in China, greatly affect the business processes. Within the guanxi system there is the concept of face which was found to affect employee propensity to stay as well as, as a novel academic result, employees’ knowledge sharing intention.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The goal of this study is to deepen the understanding of the customer portfolio management process. There are many models for the process, and they are not necessarily exclusive of each other. Consequently, the inclusion of many models might even prove out to be beneficial. Other theoretical framework include the current economical situation and its propose on customer portfolio management. With an understanding of the theoretical models as a background, the empirical part of this study compares Finnish multinational medical and healthcare technology companies’ customer portfolio management practices. The empirical research was carried out with theme interviews held with 11 sales and marketing managers or directors from four different companies. The goal was to discover the most essential practices of the process steps in the companies. The result of this study is that there is a lack of systematic customer portfolio management, but most companies are aiming to improve this in the near future. The most essential practices are analysis of sales, communication level, learning, and commitment to strategy of the focal company. Special characteristics of this industry include large business networks that include customers, professional end-users, institutions, universities, researchers, and key opinion leaders. The management and analysis of this comprehensive network has been seen to be extremely important for this industry.