Manja Kitek Kuzman

Comparison of some aggregation techniques using group analytic hierarchy process

We presented and employed seven simple group AHP aggregation techniques.The LW-AHP model was a well evaluated group AHP method.For non-homogenous group we suggest to divide the group in smaller homogenous groups.One of our new group methods, the WGM-WAM or the WGM-LW-AHP can be employed. Group decision making is an important part of multiple criteria decision making and the analytic hierarchy process (AHP). The aim of this paper was to compare group AHP methods. Seven simple group AHP aggregation techniques that could be attractive for applications selected from the vast array of group AHP models proposed in the literature were selected for evaluation. We developed three new measures of evaluation: group Euclidean distance, group minimum violations, and distance between weights for the purpose of evaluation. The results of seven group AHP methods of the theoretical example were evaluated by three new evaluation measures, satisfactory index and fitting performance index. Furthermore, a case study of a decision making problem from the construction engineering field was performed and nine group AHP aggregation techniques, seven of them formerly presented and two new two stage group approaches were applied. Finally, the case study was evaluated using all five measures for each of the nine group decision making methods. The results showed that not all group AHP methods are equally convenient and that the selection of the method depended on the specific application.

Use of wood powder and adhesive as a mixture for 3D printing

In recent years there has been much development in the field of additive manufacturing technologies, but only a few attempts have been made to use natural materials like wood for 3D printing. In this research different ratios of wood powder were used as a component in adhesive mixtures for 3D printing. Polyvinyl acetate and urea–formaldehyde adhesives were used as binders, and the optimum mixture was determined by measuring the corresponding extrusion forces. Simple blocks were 3D printed and the bending properties of these blocks were investigated. The bending strength depended on the amount of wood powder in the mixture and on the type of adhesive.

The effect of the heat treatment of spruce wood on the curing of melamine–urea–formaldehyde and polyurethane adhesives

The effect of the heat treatment of spruce wood on the curing of melamine–urea–formaldehyde (MUF) and polyurethane (PUR) adhesives was monitored by measuring their rheological properties by means of a rheometer. Instead of the standard aluminium discs, wooden discs, made from heat-treated wood with different degrees of thermal modification and conditioned in different climates, were used. The wooden discs provided more realistic curing of the adhesives compared to the real-life bonding of wood, because of solvent absorption. The results of the rheological measurements suggested that the modified wood inhibited the curing of MUF and PUR adhesives. The curing of the MUF adhesive was slower because of the reduced absorption of water from the adhesive. The curing of the one-component PUR adhesive was affected by the lower moisture content (MC) of the modified wood.

Adhesive bonding of 3D-printed ABS parts and wood

Abstract Additive manufacturing, also known as 3D printing technology, has experienced massive growth in the last decade. Instead of printing the entire product, 3D printing can be used to produce only the most complex parts, which are then combined with simple, non-printed parts from other materials to make the final product. In addition to mechanical connections, adhesive bonding is most commonly used to combine printed parts with other elements. In this study, the influence of 3D-printing parameters on the bond shear strength of 3D-printed Acrylonitrile-butadiene-styrene copolymer parts bonded to beech wood was investigated. Three printing settings with different layer thicknesses (0.39, 0.19, 0.09 mm) and a posttreatment method that utilized acetone vapour were used. The three different adhesives applied were commercial one-component polyurethane adhesive, hot melt adhesive for edge bonding, and a two-component polyurethane adhesive. The results show that the type of adhesive had the biggest influence on the strength of the bond. The highest bond strength was achieved using a two-component polyurethane adhesive. The type of failure (failure in wood, plastic, adhesive, or cohesive failure) depended greatly on the type of adhesive and thickness of the printed layer.

Finite element simulations of the loading and deformation of plywood seat shells

Modern 3D modelling software reduces the need for a large number of prototypes, means fewer product-development cycles and lower costs (time/cost), as well as improving the quality of furniture designs. However, the mechanical testing of final products is still required in order to confirm the simulation results. In this study the theoretical behaviors of different plywood seating shells (using the SolidWorks® FEM simulation software) were compared with the real results obtained using tests to measure the deformation of the backrest. The deviations of the actual deformation from the simulation were significant for the different shells and increased with loading above the elastic deformation limit of the material. It was concluded that the SolidWorks® simulation software could be effectively used in the calculation of the component displacements, strains, and stresses of seat designs subject to internal and external loads.

Forest Sector Sustainability Communication in Europe: a Systematic Literature Review on the Contents and Gaps

Purpose of ReviewStakeholder communication plays an important role in enhancing the societal sustainability and business acceptability of the forest sector. The purpose of this study is to present the current state of forest sector communication research with its stakeholders at different hierarchical levels of sustainability (i.e., societal, sectorial, corporate, and product sustainability) in Europe.Recent FindingsA systematic literature review was implemented to acquire information on the research outcomes related to sustainability communication between the forest sector and different stakeholders presented in international peer-reviewed journals between 2005 and 2015. The examined literature emphasizes the role of stakeholder communication for forest sector sustainability and acceptability, but no specific information seems to exist on how to communicate and build the forest sector image in the eyes of different stakeholders.SummaryThe gap in the research information indicates that there is a need for more theoretical and empirical work on communication and image-building processes by, e.g., recognizing the specific communication needs of different stakeholders via two-way and proactive information exchange. In the development process of forest sector communication and image building, more efforts on sending well-specified messages for well-targeted audiences should be made.

Možnosti uporabe lesa v dodajalnih tehnologijah (3D-tiskanju) / Possible uses of wood in additive technologies (3D printing)

Additive manufacturing technologies have developed greatly over the last decade in terms of technology and printing materials. Special emphasis is placed on the development of cheaper materials that are derived from natural sources, without the release of harmful substances during the manufacturing process, with the possibility of using waste materials and recycling after service life. Wood or wood residues are among the potential raw materials that could be used for 3D printing in combinations with natural and synthetic polymers. It is anticipated that, with the development of additive technologies, the use of wood will also expand to the area of structural elements, such as in the construction of prefabricated houses. A review of publications on the topic of 3D printing with natural raw materials with an emphasis on wood biomass and technologies, where the use of wood particles is possible, was made.

Building Materials and Sustainability

This chapter introduces wood and wood-based composites used in timber architecture (Sect. 2.1). Slovenian production, export, and import, as well as trade flows of primary wood products are presented and discussed. The primary wood-based products used in Slovenian timber architecture, together with current development in the field are described in Sect. 2.2. The chapter concludes with environmental impacts of primary wood products, including carbon storage mechanism and introduction of Environmental Product Declarations (EPDs) in Sect. 2.3.

Timber Architecture: Case Studies

This chapter introduces built architectural structures from Slovenia, which represent many different types of buildings that all share a common constructional material—wood, a renewable material that stores carbon. It highlights the importance of architectural design in different building types: residential buildings, office buildings, commercial buildings, industrial buildings, buildings for education, religious buildings, urban/landscape design, touristic facilities, etc. Common parameters for all case studies are: Key figures: location, building year, architect. Construction: construction company, construction time, construction description. Energy performance: energy class, operational energy use, and house technique. The chapter introduces 57 residential and public structures that are examples of buildings with a high degree of prefabrication, sustainability awareness, are references to nature, and can adapt to different individual situations due to their flexibility.

Comparison of Different Construction Types for Public Buildings Applying the Analytic Hierarchy Process

Considering the growing importance of energy-efficient building methods, timber construction will play an increasingly important role in the future. In order to determine advantages and disadvantages of using wood as a leading constructional material, different construction types were compared: solid wood, wood-frame, concrete, and brick construction. To quantify the comparisons the analytic hierarchy process (AHP) was applied. AHP enables the inclusion of various parameters, including descriptive ones, in a mathematical model through which the importance of each construction criterion forming part of the system can be calculated in order to provide objective decisions for construction. Analysis revealed that the top ranked criteria in decision-making include embodied energy, construction cost and design. On comparing different construction types the wood-frame construction, which can have very low or negative carbon footprint, was considered as the most suitable option for public building.