171 resultados para Wood construction
Resumo:
Novel biomaterials are needed to fill the demand of tailored bone substitutes required by an ever‐expanding array of surgical procedures and techniques. Wood, a natural fiber composite, modified with heat treatment to alter its composition, may provide a novel approach to the further development of hierarchically structured biomaterials. The suitability of wood as a model biomaterial as well as the effects of heat treatment on the osteoconductivity of wood was studied by placing untreated and heat‐treated (at 220 C , 200 degrees and 140 degrees for 2 h) birch implants (size 4 x 7mm) into drill cavities in the distal femur of rabbits. The follow‐up period was 4, 8 and 20 weeks in all in vivo experiments. The flexural properties of wood as well as dimensional changes and hydroxyl apatite formation on the surface of wood (untreated, 140 degrees C and 200 degrees C heat‐treated wood) were tested using 3‐point bending and compression tests and immersion in simulated body fluid. The effect of premeasurement grinding and the effect of heat treatment on the surface roughness and contour of wood were tested with contact stylus and non‐contact profilometry. The effects of heat treatment of wood on its interactions with biological fluids was assessed using two different test media and real human blood in liquid penetration tests. The results of the in vivo experiments showed implanted wood to be well tolerated, with no implants rejected due to foreign body reactions. Heat treatment had significant effects on the biocompatibility of wood, allowing host bone to grow into tight contact with the implant, with occasional bone ingrowth into the channels of the wood implant. The results of the liquid immersion experiments showed hydroxyl apatite formation only in the most extensively heat‐treated wood specimens, which supported the results of the in vivo experiments. Parallel conclusions could be drawn based on the results of the liquid penetration test where human blood had the most favorable interaction with the most extensively heat‐treated wood of the compared materials (untreated, 140 degrees C and 200 degrees C heat‐treated wood). The increasing biocompatibility was inferred to result mainly from changes in the chemical composition of wood induced by the heat treatment, namely the altered arrangement and concentrations of functional chemical groups. However, the influence of microscopic changes in the cell walls, surface roughness and contour cannot be totally excluded. The heat treatment was hypothesized to produce a functional change in the liquid distribution within wood, which could have biological relevance. It was concluded that the highly evolved hierarchical anatomy of wood could yield information for the future development of bulk bone substitutes according to the ideology of bioinspiration. Furthermore, the results of the biomechanical tests established that heat treatment alters various biologically relevant mechanical properties of wood, thus expanding the possibilities of wood as a model material, which could include e.g. scaffold applications, bulk bone applications and serving as a tool for both mechanical testing and for further development of synthetic fiber reinforced composites.
Resumo:
The forthcoming media revolution of exchanging paper documents to digital media in construction engineering requires new tools to be developed. The basis of this bachelor’s thesis was to explore the preliminary possibilities of exporting imagery from a Building Information Modelling –software to a mobile phone on a construction yard. This was done by producing a Web Service which uses the design software’s Application Programming Interface to interact with a structures model in order to produce the requested imagery. While mobile phones were found lacking as client devices, because of limited processing power and small displays, the implementation showed that the Tekla Structures API can be used to automatically produce various types of imagery. Web Services can be used to transfer this data to the client. Before further development the needs of the contractor, benefits for the building master and inspector and the full potential of the BIM-software need to be mapped out with surveys.
Resumo:
The development of bioenergy on the basis of wood fuels has received considerable attention in the last decades. The combination of large forest resources and reliance on fossil fuels makes the issue of wood chips usage in Russia an actual topic for the analysis. The main objective of this study is to disclose the current state and perspectives for the production of wood chips and their usage as a source of energy in the North-West of Russia. The study utilizes an integrated approach to explore the market of wood chips on the basis of comprehensive analysis of documentation and expert opinions. The analysis of wood chips market was performed for eight regions of the North-West district of Russia within two major dimensions: its current state and perspectives in the nearest five years. The results of the study show a comprehensive picture of the wood chips market, including the potential for wood chips production, the specific features of production and consumption and the perspectives for the market development within the regions of the North-West district of Russia. The study demonstrated that the market of wood chips is underdeveloped in the North-West of Russia. The findings of the work may be used by forest companies for the strategic planning.
Resumo:
Unlike their counterparts in Europe and America, the citizen organizations acting for the well-being of animals in Japan have not received scholarly attention. In this research, I explore the activities of twelve Japanese pro-animal organizations in Tokyo and Kansai area from the perspective of social movement and civil society studies. The concept of a ‘pro-animal organization’ is used to refer generally to the collectives promoting animal well-being. By using the collective action frame analysis and the three core framing tasks – diagnostic, prognostic, and motivational – as the primarily analytical tools, I explore the grievances, tactics, motivational means, constructions of agency and identity as well as framing of civil society articulated in the newsletters and the interviews of the twelve organizations I interviewed in Japan in 2010. As the frame construction is always done in relation to the social and political context, I study how the organizations construct their roles as civil society actors in relation to other actors, such as the state, and the idea of citizen activism. The deficiencies in the animal welfare law and lack of knowledge among the public are identified as the main grievances. The primary tactic to overcome these problems was to educate and inform the citizens and authorities, because most organizations lack the channels to influence politically. The audiences were mostly portrayed as either ignorant bystanders or potential adherents. In order to motivate people to join their cause and to enforce the motivation within the organization, the organizations emphasized their uniqueness, proved their efficiency, claimed credit and celebrated even small improvements. The organizations tended to create three different roles for citizen pro-organizations in civil society: reactive, apolitical and emphatic animal lovers concentrating on saving individual animals, proactive, educative bridge-builders seeking to establish equal collaborative relations with authorities, and corrective, supervising watchdogs demanding change in delinquencies offending animal rights. Based on the results of this research, I suggest that by studying how and why the different relations between civil society and the governing actors of the state are constructed, a more versatile approach to citizens’ activism in its context can be achieved.
Resumo:
Segregering eller segregation är ett fenomen som kan förekomma inom olika områden av samhället. Inom samhällsvetenskaperna kan segregering definieras som det rumsliga åtskiljandet av befolkningsgrupper på urval av ras eller etniskt ursprung, kön, social härkomst, religion, ålder, yrke, osv. Segregering av befolkningsgrupper sker ofta mer eller mindre frivilligt och är motsatsen till integration. Inom partikelteknologi definieras segregering oftast som det rumsliga åtskiljandet av beståndsdelarna i en blandning av olika partiklar. Segregering sker då på urval av bl.a. partiklarnas storlek, densitet, form, elektrostatiska eller mekaniska egenskaper, och kan beskrivas som motsatsen till blandning. Segregeringsmekanismer används för att förklara hur och varför en partikelblandning segregerar samt vad slutresultatet i form av den rumsliga fördelningen av partiklarna blir till följd av att blandningen utsetts för en viss behandling. I denna avhandling har segregering av partikelblandningar och speciellt torra mineralbaserade byggmaterial (t.ex. murbruk) till följd av lagring i siloer studerats. Vid industriell produktion av mineralbaserade byggmaterial används siloer för korttidslagring av slutprodukterna precis innan förpackning. Segregering leder till kraftiga variationer i sammansättningen för partikelströmmen ut ur silon, vilket gör att slutprodukterna inte uppfyller kvalitetskraven och kan därmed inte säljas till kunder. Detta leder till arbetsam och dyr bearbetning (återcirkulation) av produkterna med påföljder för produktionsekonomin samt hållbara utvecklingen. I avhandlingen identifierades de väsentligaste segregeringsmekanismerna för torra mineralbaserade byggmaterial i siloer. Dessutom klargjordes effekterna av materialegenskaper, processbetingelser och siloparametrar. Slutligen behandlas möjliga åtgärder för minskning av partikelsegregering i siloer samt tillämpning av matematiska metoder för simulering av partikelflöden med hjälp av datorer.
Resumo:
Human trafficking is not a new phenomenon. It has existed in various forms for ages around the world. Some researchers have even compared it to slavery, calling it the modern form of slavery in the 21st century. This study is particularly interested in the role of work-related human trafficking in Finnish business. In order for something to be called work-related human trafficking, the concepts of forced labour and human trafficking have to overlap. From the economic point of view, human trafficking is governed by the laws of supply and demand. In many countries the global pressure on cutting costs has created two trends: the increased supply of migrant workers and the deregulation of labour markets. These competitive pressures can have an adverse impact on the conditions of employment and, in the worst cases, can lead to forced labour and trafficking. In fact, trafficking has become one of the most profitable illicit industries worldwide, generating tremendous profits due to its low costs and huge profits. Therefore, it is important to investigate the phenomenon from the business point of view. This study is a qualitative research conducted by using theme interviews as a research approach. Altogether 13 interviews have been conducted and some secondary data has been used in order to find out what the role of human trafficking is in Finnish business. The special sectors investigated are the Finnish construction and service sectors. The theory framework used in this study follows the stakeholder approach. The relevant stakeholder groups for this study are: ‘institutions and authorities’, ‘law enforcement’, ‘management’ and ‘employees – potential victims’ of trafficking. With the help of these stakeholder groups, a holistic picture of the phenomenon is formed. It can be concluded that the role of human trafficking is complicated but it does exist in Finnish business. It appears in low-cost business sectors where the demand for cheap labour is high. Thus, often the victims are foreigners who do not know the culture or the Finnish conditions of employment. Especially smaller Finnish companies are at risk of getting involved in human trafficking or related exploitation cases since monitoring is much more scarce in these firms than in larger companies. The risk of human trafficking and exploitation is also higher at the bottom of the complicated subcontracting chains or when using foreign recruitment agencies. Thus, the study believes that active and intensive collaboration between the company’s different stakeholder groups is needed in order to prevent work-related human trafficking from flourishing in Finland.
Resumo:
The construction material sector, as a capital intensive industry, is highly vulnerable to rapid fluctuations in the economic cycles. In Finland this was witnessed especially during the late 2000s, as in 2007 and 2008 the demand for several construction materials exceeded their supply and right after this, in 2009 the demand collapsed fast as a result of an international recession. These factors brought about the need to study the future trends of the market place of the commissioning company, Finnsementti Oy. As reliable short term market forecasts for the sector are difficult to compose, the study concentrates primarily in examining and identifying the trends that are likely to affect the Finnish cement industry, and as an extension, the concrete industry in a frame of 10 to 15 years. The study’s scope comprehends also the examination of the domestic construction sector, as it represents the end user industry of both cement and concrete. These motives for the study produce the research problem, which is to conduct a trend analysis for cement based building in the Finnish market area in the 2020s. The theoretical frame for composing a trend analysis in the case of this study is twofold. This is due to the fact that both, the macro and micro environments of the examined industries are studied. The main methods used are the PESTE-model (macro) and Porter’s five forces model (micro). The study applies a qualitative approach and the data is gathered by interviewing a group of experts from the cement, concrete and construction industries. The result of the paper is an overall trend analysis for the Finnish cement based building sector, which is based on ‘sub trend analyses’ concerning four identified sub-sectors of the Finnish construction industry. The results are a combination of findings from these sub-sectors and the analyzed data that deals with the studied sector’s macro and micro environment. The conclusions provide an overall picture of the examined sectors’ potential future as a whole and by defined sub-sectors of the construction industry. The recognition of future trends in different areas of the construction industry can be applied as a means for an industry actor’s decision making and in estimating the types of construction that are likely to grow or decline. Finally, based on the analyzed data and conclusions, the commissioning company is provided with a brief SWOT analysis, that provides additional tools for decision making and planning processes regarding the future.
Resumo:
Ett huvudmål med denna avhandling var att erhålla ny information om växelverkan mellan metalljoner i vattenfas och träbaserade material såsom olika pappersmassor, ved och bark. Material av gran, tall och björk har studerats. En ny känslig kolonnkromatografisk metod utvecklades för bestämning av affinitetsordningar för 17 olika metalljoner. Av dessa bands trevärt järn och de mycket toxiska tungmetallerna bly, koppar och kadmium starkast till de studerade materialen. Växelverkan i dessa tvåfas system sker som jonbyte, huvudsakligen via komplexbildning av metalljoner till funktionella grupper i den fasta fasen. Vattenfasens pH är den viktigaste parametern som bestämmer totala halten av metalljoner som binds till materialen. Resultatet i denna avhandling kan delvis betraktas som grundforskning. En ny kunskap om metalljoners förekomst och kemiska reaktioner i dessa system är även av stor ekonomisk och ekologisk, betydelse, när man strävar till allt mera slutna system i moderna massafabriker. Avhandlingen visar också att trädbark har stor potential för biosorption av tungmetaller t.ex. från avfallsvatten. Trädbark har nästan lika stor bindningskapacitet som dyra syntetiska jonbytare.