Wood Thermal Properties

Wood thermal properties specify the answers to the questions related to heat transfer. The values of specific heat, thermal conductivity, and thermal diffusivity were simultaneously determined with quasistationary method. Wood is distinguished as a natural material for accumulating the energy by heat transfer, as isolating material, with the ability to slowly equilibrate its different temperatures. The measured thermal properties value of beech and fir wood samples support those conclusions. Known dependences of wood thermal properties on anatomical direction, density at given moisture content, temperature are modelled and incorporated into heat conduction equation to provide base for next evaluation of measured data. The heat conduction solutions, based on known wood thermal properties, are used in similar problems. It is shown that thermal properties influence the surface equilibrium temperature between skin and wooden sample and the solution of heat conduction equation describes the flux passing through the log as an element of log-cabin house. Also thermal diffusivity is a component of equation that determines the position of observed point of wood during conduction. The results served as a base point for planning the experiments, for designing the processes of heat transfer, for designing the furniture and wooden houses, for designing the machines and equipment in woodworking industry and others

Performance Evaluation of Company Stavivo IBV Using the Benchmarking Method

Bakalárska práca je zameraná na hodnotenie finančnej situácie podniku Stavivo IBV s.r.o. v rokoch 2018 až 2020, pomocou metódy benchmarkingu. Prvá časť práce sa sústreďuje na teoretické východiská práce, špecifikované sú v nej základné pojmy a vybrané ukazovatele. V druhej časti je predstavený hlavný podnik a konkurenčné, spoločne s vypracovaním finančnej analýzy, jej ukazovateľmi a ich benchmarkingom. Posledná časť práce je venovaná vlastným návrhom pre zlepšenie pozície hlavného podniku na trhu.This bachelor’s thesis focus is set on performance evaluation of company Stavivo IBV s.r.o. in years 2018 until 2020, using the method of benchmarking. The first part focuses on theoretical resources needed for thesis, specifically it is basic terms and selected indicators. The second part’s intent is on introducing the main company and secondary companies, as well as elaboration of financial analysis, its indicators and comparing them using the benchmarking method. The last part focuses on my personal proposals to improve the main’s company standing on its market segment.

Performance Evaluation of Company Stavivo IBV Using the Benchmarking Method

This bachelor’s thesis focus is set on performance evaluation of company Stavivo IBV s.r.o. in years 2018 until 2020, using the method of benchmarking. The first part focuses on theoretical resources needed for thesis, specifically it is basic terms and selected indicators. The second part’s intent is on introducing the main company and secondary companies, as well as elaboration of financial analysis, its indicators and comparing them using the benchmarking method. The last part focuses on my personal proposals to improve the main’s company standing on its market segment

Simulating Stresses Associated with the Bending of Wood Using a Finite Element Method

This article examines the stress-strain curves of various thicknesses of soft and hard wood when bent during three-point loading. The finite element method was used to simulate the course of stresses that occurred during the bending of these materials. Reference curves obtained by bending real specimens offered a basis for simulation. The results showed that with increasing material thickness, deflection values decreased and the proportionality limit increased; eventually, the bendability coefficient value decreased and the loading force necessary for bending increased. Moreover, it was apparent when bending hard materials that higher loading forces were necessary for different materials of the same thickness. It is possible to determine the stress-strain curves without having to perform experiments (except for indispensable reference ones) under real conditions

Experimental Evaluation of Joints using Thin Steel Angles for Wood Structures

The load-bearing capacity of joints using thin steel elements for wood buildings was considered. Six variants of a specific type of joint consisting of two wood elements in a ceiling structure joined by steel angles were experimentally tested. These variants differed in utilization of nails as well as screws (of various lengths) for wood. Another observed factor was the percentage of holes filled in the angles. In this work the percentage of holes filled means how many of the holes in the steel angles were filled by nails/screws. The evaluation characteristic was the maximum loading force at the breaking point. Based on the results, a set of recommendations for designing a specific type of joint with steel angles was formulated. The results showed that during loading of the joints, tensile stresses occur in the direction perpendicular to the fibers, which causes a failure of the wood parts of the joints

Dimensional Changes of Veneer Layered Materials after Cold Pressing

Dimensional changes in both non-densified and densified, thin, wooden components and layered materials after external pressing forces were released were evaluated in this work. Densification was carried out using a cold process on a semi-automatic hydraulic pressing machine. The specimens’ dimensional stabilities, focusing mainly on their residual plastic deformations, were monitored. The impacts of several factors, such as wood species, material thickness, densification degree, and their combinations, were analyzed. Results showed that, with increased degree of densification, the relative plastic deformations (pressing degree) usually decreased. With regard to the compositions explored, the best combination was a top poplar layer densified by 10% plus a bottom beech layer densified by 20%. The impacts of each of the factors on the pressing degree values proved to be significant; the least significant was the bottom beech layer thickness and degree of densification. The greatest practical benefits can be obtained using the recommended combinations of composite layers