997 resultados para Wood construction
Resumo:
Objective: To develop and validate an instrument for measuring the acquisition of technical skills in conducting operations of increasing difficulty for use in General Surgery Residency (GSR) programs. Methods: we built a surgical skills assessment tool containing 11 operations in increasing levels of difficulty. For instrument validation we used the face validaity method. Through an electronic survey tool (Survey MonKey(r)) we sent a questionnaire to Full and Emeritus members of the Brazilian College of Surgeons - CBC - all bearers of the CBC Specialist Title. Results: Of the 307 questionnaires sent we received 100 responses. For the analysis of the data collected we used the Cronbach's alpha test. We observed that, in general, the overall alpha presented with values near or greater than 0.70, meaning good consistency to assess their points of interest. Conclusion: The evaluation instrument built was validated and can be used as a method of assessment of technical skill acquisition in the General Surgery Residency programs in Brazil.
Resumo:
The aim of the thesis was to find the effects of World Trade Organization and economic integration on the wood sourcing process from Russia to Finland and to the European Union. Also, the fo reign direct investments to Russian forest industry are studied within the WTO and Economic integration framework. Qualitative interviews were carried out as primary data (total of 5 interviews). Research studies and articles regarding the same subject were used as secondary data. Results show that companies may increase their volumes of imported timber from Russia due to the reduction of custom tariffs. Russian companies are becoming more productive, but there are still several problems with legislation, infrastructure, availability and harvesting profitability in some areas. These suggest that sourcing process may not be profitable in the future. The Russian forest industry sector will not gain significant foreign direct investments in the recent years because of the infrastructure and overall atmosphere of investments. Forest industry is not seen as profitable enough. The demand for cellulose and paper in Russia is not increasing fast enough and the cost inflation is cutting the profits made from producing in Russia.
Resumo:
Diplomityön tavoitteena oli selvittää Etelä-Karjalan alueen yritysten jätevirtoja ja sekalaisen rakennusjätteen koostumusta. Jätevirtojen selvityksessä keskityttiin metsäteollisuuden, rakennusteollisuuden ja kaupan alan jätevirtoihin. Tarkoituksena oli selvittää mahdollisessa jätteenkäsittelylaitoksessa hyödynnettävien jätejakeiden määrät. Selvitettyjen tietojen perusteella arvioitiin erilaisten jätteenkäsittelyvaihtoehtojen kannattavuutta yritysnäkökul-masta Etelä-Karjalan alueella. Rakennusjätteen koostumusta tutkittiin lajittelemalla ja pun-nitsemalla sekalaisia rakennusjätekuormia jätejakeittain. Etelä-Karjalan alueen jätevirtoja selvitettiin muun muassa yrityshaastatteluin ja hyödyntämällä Lassila & Tikanoja Oyj:n tietokantaa. Sekalaisen rakennusjätteen lajittelututkimuksessa selvisi, että sekalaisissa rakennusjäte-kuormissa on lähes 50 m-% hyödynnettävissä olevia jätejakeita. Energiajaetta kuormissa oli yhteensä noin 34 m-% ja kaatopaikkajätettä noin 52 m-%. Kaupan alalta syntyy pää-sääntöisesti paljon pakkausmateriaaleista koostuvaa energiajaetta, kun taas metsäteollisuu-desta syntyy paljon erilaisia prosessijätteitä, joita ei voida hyödyntää työssä tutkituilla me-netelmillä. Lappeenrannan ja Imatran alueilla arvioidaan syntyvän energiajaetta metsäteol-lisuudesta, kaupan alalta ja rakennusteollisuudesta yhteensä noin 4 300 t, puujätettä noin 5 000 t ja sekalaista rakennusjätettä noin 11 700 t. Metsäteollisuuden, rakennusteollisuuden ja kaupan alan jätevirrat Etelä-Karjalassa eivät ole riittävät taloudellisesti kannattavan jätteenkäsittelylaitoksen perustamiseksi. Arvioinnissa huomioitiin laitoksen investointikustannukset sekä muut aiheutuvat kustannukset. Energiajakeen siirtokuormausasema todettiin kannattavaksi tilanteessa, jossa energiajae toimitettaisiin Etelä-Karjalan sijasta Lahteen tai Kouvolaan.
Resumo:
This thesis is based on computational chemistry studies on lignans, focusing on the naturally occurring lignan hydroxymatairesinol (HMR) (Papers I II) and on TADDOL-like conidendrin-based chiral 1,4-diol ligands (LIGNOLs) (Papers III V). A complete quantum chemical conformational analysis on HMR was previously conducted by Dr. Antti Taskinen. In the works reported in this thesis, HMR was further studied by classical molecular dynamics (MD) simulations in aqueous solution including torsional angle analysis, quantum chemical solvation e ect study by the COnductorlike Screening MOdel (COSMO), and hydrogen bond analysis (Paper I), as well as from a catalytic point of view including protonation and deprotonation studies at di erent levels of theory (Paper II). The computational LIGNOL studies in this thesis constitute a multi-level deterministic structural optimization of the following molecules: 1,1-diphenyl (2Ph), two diastereomers of 1,1,4-triphenyl (3PhR, 3PhS), 1,1,4,4-tetraphenyl (4Ph) and 1,1,4,4-tetramethyl (4Met) 1,4-diol (Paper IV) and a conformational solvation study applying MD and COSMO (Paper V). Furthermore, a computational study on hemiketals in connection with problems in the experimental work by Docent Patrik Eklund's group synthesizing the LIGNOLs based on natural products starting from HMR, is shortly described (Paper III).
Resumo:
Työllä oli kaksi tavoitetta: tutkia betonielementtejä valmistavan Lipa-Betoni Oy:n myynnin ja markkinoinnin tilaa sekä laatia markkinointisuunnitelma Sepa Oy:n kanssa yhteistyössä kehitetylle puubetonivälipohjalaatalle. Tutkimus jakautui nähden tavoitteiden mukaisiin tutkimusosioihin. Rakennusalan markkinointi, tarkemmin betonielementtien markkinointi, voidaan suurelta osin nähdä projektien markkinointina. Siksi työn teoriaosuudessa käsiteltiin rakennusalan markkinointia projektimarkkinoinnin näkökulmasta; erityispiirteitä, vaiheita, referenssien ja asiakassuhteiden merkitystä sekä proaktiivista markkinointistrategiaa. Lisäksi tutkittiin markkinoinnin suunnitteluun, markkinoinnin kilpailukeinoihin sekä markkinoinnin tehokkuuden mittaamiseen liittyviä teorioita. Työn tuloksena esitettiin kehitysehdotukset Lipa-Betoni Oy:n myynnin ja markkinoinnin tehostamiseksi. Konkreettisimmat tulokset tästä tutkimusosiosta ovat asiakkuuksien hoitomalli segmenteittäin ja markkinoinnin tehokkuuden mittaristo. Kehitysehdotuksien yhteenvetona laadittiin Lipa-Betoni Oy:n markkinoinnin prosessimalli. Puubetonivälipohjalaatalle laadittiin markkinointisuunnitelma. Puubetonivälipohjalaatan markkinoinnissa korostuu proaktiivinen markkinointistrategia, jonka avulla saadaan tärkeitä referenssejä tukemaan tulevaisuuden markkinointityötä.
Resumo:
Developing software is a difficult and error-prone activity. Furthermore, the complexity of modern computer applications is significant. Hence,an organised approach to software construction is crucial. Stepwise Feature Introduction – created by R.-J. Back – is a development paradigm, in which software is constructed by adding functionality in small increments. The resulting code has an organised, layered structure and can be easily reused. Moreover, the interaction with the users of the software and the correctness concerns are essential elements of the development process, contributing to high quality and functionality of the final product. The paradigm of Stepwise Feature Introduction has been successfully applied in an academic environment, to a number of small-scale developments. The thesis examines the paradigm and its suitability to construction of large and complex software systems by focusing on the development of two software systems of significant complexity. Throughout the thesis we propose a number of improvements and modifications that should be applied to the paradigm when developing or reengineering large and complex software systems. The discussion in the thesis covers various aspects of software development that relate to Stepwise Feature Introduction. More specifically, we evaluate the paradigm based on the common practices of object-oriented programming and design and agile development methodologies. We also outline the strategy to testing systems built with the paradigm of Stepwise Feature Introduction.
Resumo:
The major type of non-cellulosic polysaccharides (hemicelluloses) in softwoods, the partly acetylated galactoglucomannans (GGMs), which comprise about 15% of spruce wood, have attracted growing interest because of their potential to become high-value products with applications in many areas. The main objective of this work was to explore the possibilities to extract galactoglucomannans in native, polymeric form in high yield from spruce wood with pressurised hot-water, and to obtain a deeper understanding of the process chemistry involved. Spruce (Picea abies) chips and ground wood particles were extracted using an accelerated solvent extractor (ASE) in the temperature range 160 – 180°C. Detailed chemical analyses were done on both the water extracts and the wood residues. As much as 80 – 90% of the GGMs in spruce wood, i.e. about 13% based on the original wood, could be extracted from ground spruce wood with pure water at 170 – 180°C with an extraction time of 60 min. GGMs comprised about 75% of the extracted carbohydrates and about 60% of the total dissolved solids. Other substances in the water extracts were xylans, arabinogalactans, pectins, lignin and acetic acid. The yields from chips were only about 60% of that from ground wood. Both the GGMs and other non-cellulosic polysaccharides were extensively hydrolysed at severe extraction conditions when pH dropped to the level of 3.5. Addition of sodium bicarbonate increased the yields of polymeric GGMs at low additions, 2.5 – 5 mM, where the end pH remained around 3.9. However, at higher addition levels the yields decreased, mainly because the acetyl groups in GGMs were split off, leading to a low solubility of GGMs. Extraction with buffered water in the pH range 3.8 – 4.4 gave similar yields as with plain water, but gave a higher yield of polymeric GGMs. Moreover, at these pH levels the hydrolysis of acetyl groups in GGMs was significantly inhibited. It was concluded that hot-water extraction of polymeric GGMs in good yields (up to 8% of wood) demands appropriate control of pH, in a narrow range about 4. These results were supported by a study of hydrolysis of GGM at constant pH in the range of 3.8 – 4.2 where a kinetic model for degradation of GGM was developed. The influence of wood particle size on hot-water extraction was studied with particles in the range of 0.1 – 2 mm. The smallest particles (< 0.1 mm) gave 20 – 40% higher total yield than the coarsest particles (1.25 – 2 mm). The difference was greatest at short extraction times. The results indicated that extraction of GGMs and other polysaccharides is limited mainly by the mass transfer in the fibre wall, and for coarse wood particles also in the wood matrix. Spruce sapwood, heartwood and thermomechnical pulp were also compared, but only small differences in yields and composition of extracts were found. Two methods for isolation and purification of polymeric GGMs, i.e. membrane filtration and precipitation in ethanol-water, were compared. Filtration through a series of membranes with different pore sizes separated GGMs of different molar masses, from polymers to oligomers. Polysaccharides with molar mass higher than 4 kDa were precipitated in ethanol-water. GGMs comprised about 80% of the precipitated polysaccharides. Other polysaccharides were mainly arabinoglucuronoxylans and pectins. The ethanol-precipitated GGMs were by 13C NMR spectroscopy verified to be very similar to GGMs extracted from spruce wood in low yield at a much lower temperature, 90°C. The obtained large body of experimental data could be utilised for further kinetic and economic calculations to optimise technical hot-water extractionof softwoods.
Resumo:
Wood contains only a very small amount of lipophilic extractives, commonly known as wood pitch. The pitch is known to cause severe problems in papermaking processes. The amount of pitch in process waters can be decreased by seasoning of the raw material prior to pulping, pulp washing, removal of pitch by flotation, adsorption of pitch onto various mineral surfaces, and retention of pitch to the fibre material by cationic polymers. The aim of this study was to determine the influence of pH on some of the methods used for pitch control. Experiments were performed using laboratory-made wood pitch emulsions with varying pH, salt concentration, hemicellulose concentration and pitch composition. These emulsions were used to study the phase distribution of resin and fatty acids, the colloidal stability of pitch with and without steric stabilisation by galactoglucomannans, and the interactions between wood pitch and mineral particles. Purification of unbleached and peroxidebleached mill process water was performed by froth flotation in combination with a foaming agent. The distribution of resin and fatty acids (RFAs) between colloidal pitch droplets and the water phase was very dependent on pH. At pH 3, almost all of the RFAs were attached to the pitch droplets, while increasing the pH led to increasing concentration of dissolved RFAs in the water phase. The presence of salt shifted the release of RFAs towards higher pH, while lower ratio of neutral pitch in the emulsion resulted in release of RFAs at lower pH. It was also seen that the dissolution and adsorption of RFAs at sudden pHchanges takes place very quickly. Colloidal pitch was more stable against electrolyte-induced aggregation at higher pH, due to its higher anionic charge. The concentration of cationic polymers needed to aggregate colloidal pitch also increased with increasing pH. The surface characteristics of solid particles, such as amount of charged groups, were very important for understanding their interactions with colloidal wood pitch. Water-soluble galactoglucomannans stabilised the colloidal pitch sterically against aggregation, but could not completely prevent interactions between wood pitch and hydrophilic particles. Froth flotation of unbleached and peroxidebleached process water showed that the pitch could be removed more effectively and selectively at low pH, compared to at neutral pH. The pitch was removed more effectively, using lower concentrations of foaming agent, from peroxide-bleached water than from unbleached water. The results show that pH has a major impact on various pulping and papermaking processes. It determines the anionic charge of the colloidal pitch and the solubility of certain pitch components. Because of this, the pH influences the effectiveness of pitch retention and removal of pitch. The results indicate that pitch problems could be diminished by acknowledging the importance of pH in various papermaking processes.
Resumo:
The portfolio as a means of demonstrating personal skills has lately been gaining prominence among technology students. This is partially due to the introduction of electronic portfolios, or e-portfolios. As platforms for e-portfolio management with different approaches have been introduced, the learning cycle, traditional portfolio pedagogy, and learner centricity have sometimes been forgotten, and as a result, the tools have been used for the most part as data depositories. The purpose of this thesis is to show how the construction of e-portfolios of IT students can be supported by institutions through the usage of different tools that relate to study advising, teaching, and learning. The construction process is presented as a cycle based on learning theories. Actions related to the various phases of the e-portfolio construction process are supported by the implementation of software applications. To maximize learner-centricity and minimize the intervention of the institution, the evaluated and controlled actions for these practices can be separated from the e-portfolios, leaving the construction of the e-portfolio to students. The main contributions of this thesis are the implemented applications, which can be considered to support the e-portfolio construction by assisting in planning, organizing, and reflecting activities. Eventually, this supports the students in their construction of better and more extensive e-portfolios. The implemented tools include 1) JobSkillSearcher to help students’ recognition of the demands of the ICT industry regarding skills, 2) WebTUTOR to support students’ personal study planning, 3) Learning Styles to determine students' learning styles, and 4) MyPeerReview to provide a platform on which to carry out anonymous peer review processes in courses. The most visible outcome concerning the e-portfolio is its representation, meaning that one can use it to demonstrate personal achievements at the time of seeking a job and gaining employment. Testing the tools and the selected open-source e-portfolio application indicates that the degree of richness of e-portfolio content can be increased by using the implemented applications.
Resumo:
The main aim of this thesis is to study the effect of mineral fillers on the properties of extruded wood-polypropylene composites (WPC). The studied minerals are Talc, Calcite (CaCO3), two quantities of Wollastonite and Soapstone, and the level of mineral addition is 20 w-%. The study shows that mineral fillers can be used to modify and improve the properties of woodplastic composites. Especially the moisture-related properties of WPCs were found to be improved significantly by mineral addition. As the WPCs of the studied type are commonly used in outdoor applications, this is of importance in terms of usability. In machining, the addition of two minerals retained the surface roughness at same level throughout the test, indicating a favorable effect on machinability. The use of hard minerals shortened the tool life in machining. In general, a modest increase in density was observed. In many of the studied properties, no apparent influence of mineral addition was found, indicating that the properties were not weakened. An overall result was that talc showed the best overall performance, indicating that it can be used as an active filler improving most of the studied properties, especially moisture resistance. Calcite was found to have nearly similar performance. According to the findings, mineral addition to wood-plastic composites appears to be beneficial; especially moisture resistance can be enhanced without diminishing the other properties or usability in general.