171 resultados para Wood construction


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Trees produce an enormous amount of compounds that are still scantly utilized.However, the results obtained from structurally similar biochemicals suggest that wood-derived compounds could be used for the protection of health in various applications. Polyphenols, for instance, could be extracted from wood in high quantities. Similar polyphenols to those in wood include resveratrol, found in grapes, and secoisolariciresinol, present in flaxseeds. Their consumption has been inversely associated with the incidence of various diseases, especially certain cancers and obesity-related disorders. The aim of this study was to determine the health-promoting effects of woodderived biochemicals. The effect of spruce hemicellulose on the growth of probiotic intestinal bacteria was studied. The results suggest that the bifidobacteria and lactobacilli can utilize hemicellulose and thus it has potential as a prebiotic compound. In particular, the efficacy of pine polyphenols to inhibit the growth of prostate cancer was our main interest. It was found that stilbenoids and lignans inhibited the proliferation of various cancer cells, and reduced the growth of prostate cancer xenografts in mice. The polyphenol rich pine knot extract was well tolerated in diet and extract-derived polyphenols were rapidly absorbed after intake. Furthermore, we determined the effect of the dietary pine knot extract on the weight gain and the expression of aromatase gene in reporter mouse expressing the promoter region of a human aromatase gene. It was found that dietary pine knot extract alleviated the obesity-induced inflammation in adipose tissue and downregulated the expression of a human aromatase gene. Taken together, several components of spruce and pine may have a future role as health-promoting compounds.

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There is currently little empirical knowledge regarding the construction of a musician’s identity and social class. With a theoretical framework based on Bourdieu’s (1984) distinction theory, Bronfenbrenner’s (1979) theory of ecological systems, and the identity theories of Erikson (1950; 1968) and Marcia (1966), a survey called the Musician’s Social Background and Identity Questionnaire (MSBIQ) is developed to test three research hypotheses related to the construction of a musician’s identity, social class and ecological systems of development. The MSBIQ is administered to the music students at Sibelius Academy of the University of Arts Helsinki and Helsinki Metropolia University of Applied Sciences, representing the ’highbrow’ and the ’middlebrow’ samples in the field of music education in Finland. Acquired responses (N = 253) are analyzed and compared with quantitative methods including Pearson’s chi-square test, factor analysis and an adjusted analysis of variance (ANOVA). The study revealed that (1) the music students at Sibelius Academy and Metropolia construct their subjective musician’s identity differently, but (2) social class does not affect this identity construction process significantly. In turn, (3) the ecological systems of development, especially the individual’s residential location, do significantly affect the construction of a musician’s identity, as well as the age at which one starts to play one’s first musical instrument. Furthermore, a novel finding related to the structure of a musician’s identity was the tripartite model of musical identity consisting of the three dimensions of a musician’s identity: (I) ’the subjective dimension of a musician’s identity’, (II) ’the occupational dimension of a musician’s identity’ and, (III) ’the conservative-liberal dimension of a musician’s identity’. According to this finding, a musician’s identity is not a uniform, coherent entity, but a structure consisting of different elements continuously working in parallel within different dimensions. The results and limitations related to the study are discussed, as well as the objectives related to future studies using the MSBIQ to research the identity construction and social backgrounds of a musician or other performing artists.

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The purpose of this thesis is to find development areas for site operations in power plant construction projects delivered by Wärtsilä. The inspected operations are subcontractor management, site material management and work scheduling. The contractor's role in EPC project is to respond for engineering, procurement, and construction supervision. Geographical and cultural differences brings challenges for finding development areas as Wärtsilä delivers projects world-wide. Searching for development area is mainly made with survey, which answers were collected from the target company's site personnel. Based on the results, with good planning and preparation various problems would be avoided. An external view for the thesis was collected by an expert interview, which was held to three expe-rienced construction operating executives. Interviewees believed that with the se-lection of right site personnel and clearly defined areas of responsibility will great-ly affect the outcome of the project. Some of the theory has been collected from areas, which have helped to under-stand the inspected operations on site. Improving competence knowledge has been important due to the broad scope of work and the author’s inexperience of the topic. Also generally effective practices from construction projects has been col-lected to the theory part. Functionality of general practices have been reflected together with the results of empirically collected data for Wärtsilä's projects. As a result, a model was generated where development proposals and the benefits from new procedures were presented.

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The main objective of this thesis is to study the impact of different mineral fillers and fire retardants on the reaction-to-fire properties of extruded/coextruded wood-plastic composites (WPCs). The impact of additives on the flammability properties of WPCs is studied by cone calorimetry. The studied properties are ignition time, peak heat release rate, total heat release, total smoke production, and mass loss rate. The effects of mineral fillers and fire retardants were found to vary with the type of additive, the type of additive combinations, the amount of additives, as well as the production method of the WPCs. The study shows that talc can be used to improve the properties of extruded WPCs. Especially ignition time, peak heat release rate and mass loss rate were found to be improved significantly by talc. The most significant improvement in the fire retardancy of coextruded WPCs was achieved in combinations of natural graphite and melamine. Ignition time, peak heat release rate and total smoke production were improved essentially. High increase in smoke production was found in samples where the amount of ammonium polyphosphate was 10% or higher. Coextrusion as a structural modification was found as a promising way to improve the flammability properties of composite materials in a cost-effective way.

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Software quality has become an important research subject, not only in the Information and Communication Technology spheres, but also in other industries at large where software is applied. Software quality is not a happenstance; it is defined, planned and created into the software product throughout the Software Development Life Cycle. The research objective of this study is to investigate the roles of human and organizational factors that influence software quality construction. The study employs the Straussian grounded theory. The empirical data has been collected from 13 software companies, and the data includes 40 interviews. The results of the study suggest that tools, infrastructure and other resources have a positive impact on software quality, but human factors involved in the software development processes will determine the quality of the products developed. On the other hand, methods of development were found to bring little effect on software quality. The research suggests that software quality is an information-intensive process whereby organizational structures, mode of operation, and information flow within the company variably affect software quality. The results also suggest that software development managers influence the productivity of developers and the quality of the software products. Several challenges of software testing that affect software quality are also brought to light. The findings of this research are expected to benefit the academic community and software practitioners by providing an insight into the issues pertaining to software quality construction undertakings.

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Tämä raportti käsittelee ”Torrefioidun biohiilipelletin laatu ja varastoitavuus” hankkeen tuloksia. Hankkeen tavoitteena oli tutkia torrefioidun biohiilipelletin prosessiteknologiaa, markkinoita ja tuotantokustannuksia kirjallisuustutkimusosiossa. Hankkeen päätutkimus keskittyi koeajoihin pilottilaitoksella, jossa valmistettiin biohiilipellettiä erilaisista puuraaka-aineista. Pilottilaitos oli perustettu Torrec Oy:n toimesta Etelä-Savon Energian Pursialan voimalaitoksen yhteyteen Mikkelissä ja sen tuotanto oli käynnistynyt kesällä 2014. Kaikki koe-erät valmistettiin vain käyttämällä sidonta-aineena lauhdevettä, jota oli tiivistynyt säiliön pohjalle torrefiointiprosessin aikana. Näin ollen erillistä lisäsidonta-aineita ei tarvittu, jolloin voidaan säästää tuotantokustannuksissa jatkossakin. Euroopan Unioni on asettanut 20 % tavoitteen uusiutuvien energioiden käytölle vuoteen 2020, josta biomassalla voidaan kattaa kaksi kolmannesta. Tutkimushankkeen tavoitteena oli metsään perustuvan bioenergiatuotannon lisääminen ja tuontienergian korvaaminen kotimaisella polttoaineella. Hankkeen tarkoituksena oli tutkimusanalyysien kautta kehittää uutta kilpailukykyistä teknologiavaihtoehtoa puupolttoaineiden hyödyntämiseksi. Torrefiointiteknologiaa ollaan kaupallistamassa ympäri Eurooppaa parasta aikaa ja uusia biohiilen tuotantolaitoksia on kehitteillä ja rakenteilla. Tutkimuksen tulokset osoittavat, että biohiilipelletillä on mahdollisuudet suurimittakaavaiseen energiantuotantoon laadun suhteen, kunhan sen käyttäminen tulee edullisemmaksi laitoksissa. Toisaalta, tämä kehitys vaatii tukimekanismeja valtion puolelta, jotta pelletit lähtisivät todella liikkeelle markkinoilla.

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Torrefaction is the partial pyrolysis of wood characterised by thermal degradation of predominantly hemicellulose under inert atmosphere. Torrefaction can be likened to coffee roasting but with wood in place of beans. This relatively new process concept makes wood more like coal. Torrefaction has attracted interest because it potentially enables higher rates of co-firing in existing pulverised-coal power plants and hence greater net CO2 emission reductions. Academic and entrepreneurial interest in torrefaction has sky rocketed in the last decade. Research output has focused on the many aspects of torrefaction – from detailed chemical changes in feedstock to globally-optimised production and supply scenarios with which to sustain EU emission-cutting directives. However, despite its seemingly simple concept, torrefaction has retained a somewhat mysterious standing. Why hasn’t torrefied pellet production become fully commercialised? The question is one of feasibility. This thesis addresses this question. Herein, the feasibility of torrefaction in co-firing applications is approached from three directions. Firstly, the natural limitations imposed by the structure of wood are assessed. Secondly, the environmental impact of production and use of torrefied fuel is evaluated and thirdly, economic feasibility is assessed based on the state of the art of pellet making. The conclusions reached in these domains are as follows. Modification of wood’s chemical structure is limited by its naturally existing constituents. Consequently, key properties of wood with regards to its potential as a co-firing fuel have a finite range. The most ideal benefits gained from wood torrefaction cannot all be realised simultaneously in a single process or product. Although torrefaction at elevated pressure may enhance some properties of torrefied wood, high-energy torrefaction yields are achieved at the expense of other key properties such as heating value, grindability, equilibrium moisture content and the ability to pelletise torrefied wood. Moreover, pelletisation of even moderately torrefied fuels is challenging and achieving a standard level of pellet durability, as required by international standards, is not trivial. Despite a reduced moisture content, brief exposure of torrefied pellets to water from rainfall or emersion results in a high level of moisture retention. Based on the above findings, torrefied pellets are an optimised product. Assessment of energy and CO2-equivalent emission balance indicates that there is no environmental barrier to production and use of torrefied pellets in co-firing. A long product transport distance, however, is necessary in order for emission benefits to exceed those of conventional pellets. Substantial CO2 emission reductions appear possible with this fuel if laboratory milling results carry over to industrial scales for direct co-firing. From demonstrated state-of-the-art pellet properties, however, the economic feasibility of torrefied pellet production falls short of conventional pellets primarily due to the larger capital investment required for production. If the capital investment for torrefied pellet production can be reduced significantly or if the pellet-making issues can be resolved, the two production processes could be economically comparable. In this scenario, however, transatlantic shipping distances and a dry fuel are likely necessary for production to be viable. Based on demonstrated pellet properties to date, environmental aspects and production economics, it is concluded that torrefied pellets do not warrant investment at this time. However, from the presented results, the course of future research in this field is clear.

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The aim of this Master’s Thesis is to develop project logistics functions in large scale en-gineering, procurement and construction projects. The background of the research topic is compounded from two separate subjects; OPAL Program and case study of an actual EPC project. The purpose is to examine Project Logistics process in accordance with OPAL Program as well as logistics process in focus EPC project. Both entities are researched by using the case study research methodology. Logistics process of the focus EPC project is described as well as presented and in addi-tion, logistics related findings and observations are introduced. Significant findings and observations are found from logistics costs as well as shipment volume estimations in the early phase of the focus ECP project. A notable finding is also that because goods were transported as readily assembled as possible it caused expensive oversized cargo deliveries. From findings and observation of the focus EPC project it can be derived that logistics has to be involved in the early sales phase in order to receive more accurate logistics cost esti-mations for project deliveries. It is also noticed that in order to obtain savings in logistics costs, oversized deliveries must be avoided.

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Numerous scholars have already stressed the need to prepare students prior to academic mobility (Abdallah-Pretceille, 2003; Jackson, 2013, for example) in order to face hypermodernity (Aubert, 2004). As per the new mobilities paradigm (Urry, 2007), this implies considering individuals at the centre of political and institutional issues. Furthermore, the multiplicity of terminology of references towards academic mobility, and intercultural competences, justifies this research. The theory, for this doctoral dissertation, applies “renewed interculturality” (Dervin, 2012), a move away from a culturalist approach. Intercultural competences are therefore defined as a stepping back from discourses on the Other that may emerge during encounters. In order to collect the data, six focus groups have been organised with two batches of students from a Higher Education Institution in Hong-Kong, an “education hub” (Dervin & Machart, 2014) that is striving to be competitive particularly in increasing the number of incomingand outcoming students. Training and education to interculturality have been implemented prior to academic mobility in order to observe the impact on participants’ discourses before and after the mobility. Theories of enunciation and dialogism represent the methodology allowing us to compare and analyse the reported voices in the participants’ discourse and their prosodic realisation (Martin & White, 2005) before and after the experience of academic mobility. I have attempted to observe the dialogic space available to welcome the Other during encounters in the participants’ discourse. The results seem to underline the increased number of reported voices in participants’ discourse after study abroad, but as the space opened for negotiation is instable and depends on the interlocutors and the voices addressed, consequently, further research appears necessary to study the influences of a preparation prior to mobility on the contraction or expansion of heteroglossia. All in all, this doctoral dissertation aimed to renew preparation

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This dissertation examines parental disciplinary violence against children in authority records and in the criminal procedure in Finland. The main aim is to analyze disciplinary violence, how it is defined, and how it is constructed as a crime by social workers, the police, and parents. This dissertation consists of four sub-studies and a summary article. In the first sub-study, I examine how disciplinary violence appears in child welfare documents and analyze the decision-making processes and measures taken by the child welfare workers. The second sub-study, utilizing police interview data, examines police officers’ perceptions of disciplinary violence, its criminalization, and its investigation. In addition to this analysis of police officers’ own perceptions, in the third sub-study, I use reports of crime and pre-trial investigation documents to look at what a typical suspicion of disciplinary violence coming to the attention of the police is and examine the decision-making processes of the police. Utilizing authority data, the fourth sub-study analyzes how parents rationalize the use of disciplinary violence to the authorities investigating these suspicions. The research provides findings that are unprecedented in Finland. Firstly, it was shown that social workers’ decision-making processes in suspicions of disciplinary violence follow three pathways of reasoning, with many factors taken into consideration; and in less than one-third of the cases, a request for criminal investigation has been made to the police. Secondly, it was verified that police officers hold different perceptions of disciplinary violence, and these perceptions have multiple effects on the investigation of these cases and the construction of disciplinary violence as a crime. Thirdly, the analysis of the reports of crime and pre-trial investigation documents showed that almost two-thirds of the cases of disciplinary violence had been sent to a prosecutor by the police and, thus, defined as a crime. However, in many cases, acts of disciplinary violence were often seen as ‘educational, petty one-off incidents’ and a possible trial and punishment for the perpetrator were seen as unreasonable. Fourthly, it was found that parents often try to neutralize and rationalize the violence they have used against their children, for example, either by denying the victim, the criminal intent, or the entire act, or relying on the necessity of the forbidden act. The dissertation concludes that disciplinary violence is defined and constructed in authority policies and practices, first and foremost, by the severity of the act, the nature of the act as continuous or singular, the perceived harm caused by the act to a child, and the perceptions of authorities regarding physical punishment of children. The asymmetrical power setting present in disciplinary violence and parents’ legitimized right to raise and discipline their children partly seem to explain why criminal-law processing of these suspicions of violence and understanding these as crimes is difficult. Finally, this research calls for more coherent and consistent authority practices and policies, achieved by educating authorities and increasing awareness on disciplinary violence, questions the need for a concept like ‘disciplinary’ violence, and suggests more emphasis on unambiguous perceptions of a child’s best interest.

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Hemicelluloses are potential raw material for several items produced in future wood-based biorefineries. One possible method for recovering hemicelluloses from wood extracts is ultrafiltration (UF). However, low filtration capacities and severe fouling restrict the use of tight UF membranes in the treatment of wood extracts. The lack of suitable commercial membranes creates a need for pretreatment which would decrease fouling and increase the filtration capacity. This thesis focuses on the evaluation of the possibility to improve the filtration capacity and decrease fouling with the pretreatment of wood extracts. Methods which remove harmful compounds and methods which degrade them are studied, as well as combinations of the methods. The tested pretreatments have an influence on both the concentration of different compounds and the molecular mass distribution of the compounds in the extract. This study revealed that in addition to which kind of compounds were removed, also the change in molecular size distribution affected the filtration capacity significantly. It was shown that the most harmful compounds for the filtration capacity of the hydrophobic 5 kDa membrane were the ones capable of permeating the membrane and fouling also the inner membrane structure. Naturally, the size of the most harmful compounds depends on the used UF membrane and is thus case-specific. However, in the choice of the pretreatment method, the focus should be on the removal of harmful compound sizes rather than merely on the total amount of removed foulants. The results proved that filtration capacity can be increased with both adsorptive and oxidative pretreatments even by hundreds of per cents. For instance, the use of XAD7 and XAD16 adsorbents increased the average flux in the UF of a birch extract from nearly zero to 107 kg/(m2h) and 175 kg/(m2h), respectively. In the treatment of a spruce extract, oxidation by pulsed corona discharge (PCD) increased the flux in UF from 46 kg/(m2h) to 158 kg/(m2h). Moreover, when a birch extract batch was treated with laccase enzyme, the flux in UF increased from 15 kg/(m2h) to 36 kg/(m2h). However, fouling was decreased only by adsorptive pretreatment while oxidative methods had a negligible or even negative impact on it. This demonstrates that filtration capacity and fouling are affected by different compounds and mechanisms. The results of this thesis show that filtration capacity can be improved and fouling decreased through appropriate pretreatment. However, the choice of the best possible pretreatment is case-specific and depends on the wood extract and the membrane used. Finding the best option requires information on the extract content and membrane characteristics as well as on the filtration performance of the membrane in the prevailing conditions and a multivariate approach. On the basis of this study, it can be roughly concluded that adsorptive pretreatment improves the filtration capacity and decreases fouling rather reliably, but it may lead to significant hemicellulose losses. Oxidation reduces the loss of valuable hemicelluloses and could improve the filtration capacity, but fouling challenges may remain. Combining oxidation with adsorptive pretreatment was not a solution for avoiding hemicellulose losses in the tested cases.