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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Value-added to Small-Diameter Timber (Obtained from Hardwood Plantations)

Ting-Ho Tsai (17549595) 05 December 2023 (has links)
<p dir="ltr">Thinning operations play a crucial role in ensuring forest health and sustainability. It strategically removes weaker trees and enhances overall growth by providing more essential resources such as sunlight, nutrients, and water. Small-diameter timber (SDT) is generally a byproduct of thinning operations in natural or plantation forests from either softwood or hardwood species. SDT is characterized by a diameter at breast height (DBH) of less than 9 inches for softwood and 11 inches for hardwood species.</p><p dir="ltr">Plantation forests contribute significantly to uniform material resources, needed for sustainable timber production. However, using SDT is often challenging because of the high cost of management, thinning operation, and its intrinsic characteristics, such as decreased wood properties due to the presence of juvenile wood and defects. Economic difficulties are especially evident for hardwood plantation owners because of the longer growth period of hardwoods.</p><p dir="ltr">This study explores feasible methods to enhance the value of hardwood SDT, encouraging its utilization and aiding plantation owners in offsetting management and thinning operations costs before the harvest of large-diameter timber. There are three parts: exploring potential products based on semi-products, conducting a case study by producing school furniture from six walnut SDTs, and providing recommendations for possible production from SDT.</p><p dir="ltr">Our investigation reveals strategic considerations for future school furniture producers. Establishing sorting and grading criteria, investing in more advanced machinery, producing edge-glued panels from SDT lumber, and having broader ideas for school furniture are pivotal for optimizing the SDT value-added process. The findings suggest that having a plan for the utilization of SDT, considering the recommendations provided, can elevate challenges, optimize strategies, increase the potential value of SDT from plantations, and promote sustainable and profitable use of forest resources.</p>
12

Tepelně-vlhkostní analýza konstrukcí masivních dřevostaveb / Hygrothermal analysis of massive wooden structures

Uherka, Pavel January 2016 (has links)
This thesis deals with massive wooden buildings especially with regard to the current approach to their design, assessment and approval. In this thesis are shown future possibilities of development of traditional wooden buildings with regard to current thermal technical requirements. Theoretical considerations are then compared with measurements which were performed on massive wooden wall samples.
13

DEVELOPMENT AND VALIDATION OF A VERSATILE AND INNOVATIVE TOOL TO ASSESS AND BENCHMARK SUSTAINABILITY PERFORMANCE OF ORGANIZATIONS AND SUPPLY CHAINS

Cagatay Tasdemir (6580142) 10 June 2019 (has links)
<a>Global trends and factors, such as the increased level of globalization, climate change, resource scarcity, and awareness of social and environmental responsibilities, as well as fiercer competition and lower profit margins in all industries, force organizations to act to retain, regain, or sustain their competitive advantages for long-term survival. These trends and factors are historically known to bring about innovations that drive the evolution of industries. Sustainability is considered to be such an innovation to achieve fiscally sound, environmentally conscious, and socially progressive organizations and supply chains. Sustainable Development and Sustainability notions are among trending topics of 21st century. Elevated sustainability concerns of various stakeholders have been forcing members of all industries to evolve into their more environmentally and socially responsible versions. This study was initiated through a comprehensive literature review phase that reviewed 477 articles published in five major databases from 1990 to 2018. The purpose of this review was to assess the current state-of-the art on the subject of lean-driven sustainability. Based on descriptive and contextual analysis, synergies, divergences, and the extent of two-way permeability of lean and sustainability concepts from the perspective of intra- and inter-organizational operations were identified along with future research opportunities. Fundamental strengths and weaknesses of both concepts, existing strong synergies and untapped potential, along with their key contributors, the potential-use cases of lean tools to derive sustainable solutions are highlighted in this review. Next, based on the findings of systematic literature review, an innovative, holistic, versatile and scalable tool was developed to assess and benchmark sustainability performance of organizations and supply chains. The proposed framework was established upon trivet structure of Triple Bottom Line philosophy and fueled by Lean, Six-Sigma and Life Cycle Assessment (LCA) methodologies for accurate and effective measurement of sustainability performance. Completeness of the framework was ensured through development of first-generation Key Performance Indicator (KPI) pool with 33 indicators, a unique work environment assessment mechanism for safety and environmental protection issues in terms of 11 risk categories and by construction of an ownership structure for ease of framework deployment. Proposed framework is expected to help with true sustainability performance improvement and benchmarking objectives at a range of business levels from facility to sectoral operations. Upon completion of the development phase, the Sustainability Benchmarking Tool (SBT) Framework was validated at the facility level within the context of value-added wood products manufacturing. Strengths and weaknesses of the system were identified within the scope of Bronze Frontier maturity level of the framework and tackled through a six-step analytical and quantitative reasoning methodology. The secondary objective of the validation phase was to document how value-added wood products industries can take advantage of natural properties of wood to become frontiers of sustainability innovation. In the end, True Sustainability performance of the target facility was improved by 2.37 base points, while economic and environmental performance was increased from being a system weakness to achieving an acceptable index score benchmark of 8.41 and system strength level of 9.31, respectively. Social sustainability score increased by 2.02 base points as a function of better gender bias ratio. The financial performance of the system improved from a 33% loss to 46.23% profit in the post-improvement state. Reductions in CO<sub>2</sub> emissions (55.16%), energy consumption (50.31%), solid waste generation (72.03%), non-value-added-time (89.30%) and cost performance (64.77%) were other significant achievements of the study. In the end, SBT Framework was successfully validated at the facility level and target facility evolved into its leaner, cleaner and more responsible version of itself. Furthermore, manufacturing industries of all sorts are key stakeholders, which rely on universities to satisfy the demand for competent workforce. Society also expects universities to educate youth and contribute to their self-development by achieving both, scientific and intellectual knowledge saturation. To expand the contribution of the study to the body of knowledge in the fields of Sustainability and Modern Management techniques, an undergraduate level course curriculum that integrates modern management techniques and sustainability concepts with wood products industry dynamics was developed. Students’ pre- and post-education awareness of, and familiarity with sustainability, potential consequences of ignored sustainability issues, modern management techniques, global trends, innovation waves, and industry evolution were compared through a seventeen-question survey. Results showed that course content was successful at increasing sustainability awareness at both overall and individual sustainability pillar levels, At the end, 100% of students were able to develop complete understanding of various modern management techniques and stated that they felt confident to apply learnt skills to real life issues within their profession upon graduation. Overall, this study empirically documented how synergies between Lean, Sustainability, Six-Sigma and Life Cycle Assessment concepts outweigh their divergences, demonstrated viability of SBT Framework and presented a proven example of modern management techniques powered transdisciplinary sustainability curriculum.</a>
14

Návrh a výpočet sušicího zařízení pro dřevozpracující průmysl / Design of a drying device for wood-processing industry

Vach, Tomáš January 2008 (has links)
The thesis considers a stabilization of temperature of a wood fiber during production of medium close fibre boards MDF in a wood-processing industry. The original purpose to solve energetic optimalization of a kiln dryer has become a serious problem. It turned out that production suffers with a big heat loss which results in big heat loss gained during a kiln drying. Primary aim of this thesis is an examination of a cooling effect of environment on chosen parts of a production line and suggestion of acceptable proceeding to minimize heat loss and to rise temperature of the wood fiber to required temperature. Solution is aimed on the section of a production line between drying equipment and press. First part of the thesis introduces technology of production of fibre boards, introduction to heat transfer problems and also basics of computer modeling of heat flow and transfer using CFD simulation. The next part includes an evaluation of the heat loss of chosen parts of the production line in a current working condition and its comparison with computer simulations. Verification of accuracy of the results while using both approaches to solution is a first step to the improvement of the current situation. It is possible to use the verified calculation model for the following solution of effects on convective and radiation heating of a wood fiber layer. An important factor in the last period of a calculation is a real temperature of the fiber board-mat at the entrance to a press. The higher entering temperature in a set temperature range is reached, the lower time needed for pressing will be and simultaneously the whole industrial process will be cut short. The solution of a problem leads to an achievement of an energy saving and should become a solid basis from which it would be possible to evaluate an improvement of production of MDF boards. The conclusion of the thesis includes an analysis of findings which refers to a heating of wood fiber and it’s effectiveness for a practical use.

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