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Analysis of methods for determining wood moisture by non-destructive methods
Změlík, Jiří ; Zach, Jiří (referee) ; Vaněrek, Jan (advisor)
Subject of this bachelor thesis is the analysis and comparison of hygrometers considering their price, availability and applicability. Theoretical part compared available types of hygrometers based on their operating principle. Subsequently, resistance, capacitive and microwave portable hygrometers were compared in more detail. There were five reviewed hygrometers in total, with three of them capacitive and one of each resistance and microwave. The measurement was performed on beech and spruce trees at gravimetrically known humidity, ranging from extremely low to extremely high values (even out of bounds recommended by the manufacturer). The evaluation of the methods was performed according to the Saaty´s AHP method. Hygrometers were then selected by their optimization. After the experimental part, the suitability of individual methods was determined. The best method was capacitive, followed by resistance and the worst microwave method.
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Temperature-moisture Assessment of Members in Truss with Above-rafter Thermal Insulation
Soudek, Pavel ; Vlach, František (referee) ; Kalousek, Lubor (advisor)
This thesis deals with the temperature-moisture assessment of members in truss with above-rafter thermal insulation. Within this system it focuses on the details of creating a roof overhang because that is where the timber elements are under the greatest amount of moisture stress. Different variations of this detail are presented including the extent to which thermo-technical requirements and requirements surrounding the built-in timber elements are satisfied. Theoretical calculations are then compared with measurements which were performed on a real building. This task of measurement involved developing a new measuring device. The development of this device is also described in this paper.
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Hodnocení vybraného elektrického vlhkoměru při měření vlhkosti dřeva smrku v průběhu procesu navlhání
Konečný, Filip
The content of this bachelor's thesis deals with the measurement of the moisture content of spruce wood (Picea abies (L.) Karst.) in the wetting process. Spruce wood was added to zero moisture (w = 0%) and then stored in an air-conditioned room. Wood moisture was measured using an Orion 950 dielectric hygrometer. The moisture values measured on this hygrometer were subsequently compared with the actual moisture found, which was determined using the gravimetric method. The interface of the selected hygrometer enables the setting of the wood density value as well, thus allowing the comparison of the wood moisture with the actual density and with the table density given in the tables from the wood hygrometer manufacturer. The measured spruce wood samples were divided into two groups of 15 pieces each, namely samples without defects or with only minimal defects, and samples with larger defects, especially with resin streaks or knots. Most accurately, the hygrometer measured with the actual density of the samples for both groups. There was always a very significant difference of values when the table density was set.
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Analysis of methods for determining wood moisture by non-destructive methods
Změlík, Jiří ; Zach, Jiří (referee) ; Vaněrek, Jan (advisor)
Subject of this bachelor thesis is the analysis and comparison of hygrometers considering their price, availability and applicability. Theoretical part compared available types of hygrometers based on their operating principle. Subsequently, resistance, capacitive and microwave portable hygrometers were compared in more detail. There were five reviewed hygrometers in total, with three of them capacitive and one of each resistance and microwave. The measurement was performed on beech and spruce trees at gravimetrically known humidity, ranging from extremely low to extremely high values (even out of bounds recommended by the manufacturer). The evaluation of the methods was performed according to the Saaty´s AHP method. Hygrometers were then selected by their optimization. After the experimental part, the suitability of individual methods was determined. The best method was capacitive, followed by resistance and the worst microwave method.
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Hodnocení vybraných elektrických vlhkoměrů při měření vlhkosti dřeva
Piňos, Pavel
This bachelor thesis focuses on detecting a range of humidity, in which selected electric hygrometers measure reliably and also an appropriateness of its use for measuring moisture of wood. The thesis is divided into two main parts which are a realization of the experiment and a statistic comparison and evaluation of measured data. The measuring of moisture was realized using four different types of hygrometers and then it was compared with the real (computed gravimetricaly) moisture of wood. The testing was realized on spruce samples. The next target was determining an effect of a density of wood on its real moisture. For demonstrating reliability of measuring moisture of selected hygrometers, samples were tested during five humidity conditions.
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Temperature-moisture Assessment of Members in Truss with Above-rafter Thermal Insulation
Soudek, Pavel ; Vlach, František (referee) ; Kalousek, Lubor (advisor)
This thesis deals with the temperature-moisture assessment of members in truss with above-rafter thermal insulation. Within this system it focuses on the details of creating a roof overhang because that is where the timber elements are under the greatest amount of moisture stress. Different variations of this detail are presented including the extent to which thermo-technical requirements and requirements surrounding the built-in timber elements are satisfied. Theoretical calculations are then compared with measurements which were performed on a real building. This task of measurement involved developing a new measuring device. The development of this device is also described in this paper.
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