Mjerenje i modeliranje promjena dimenzije drvocementnog kompozita tijekom sušenja i vlaženja

master's thesis

• Title (english): Measurement and modeling of dimensional changes of wood wool cement composite during drying and wetting cycles
• Author: Tena Krnić
• Mentor: Juraj Šipušić (mentor)
• Mentor: Anamarija Rogina (komentor)
• Committee member: Anamarija Rogina (predsjednik povjerenstva)
• Committee member: Katarina Mužina (član povjerenstva)
• Committee member: Jelena Macan (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2023-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Promjena dimenzije drvocementnog kompozita koja se odvija pri sušenju i vlaženju istog, iznimno je bitna stavka zbog primjene drvocementnog kompozita. U ovom radu određivana je temperatura rosišta pri sobnim uvjetima da bi se utvrdila preciznost higrometra kod određivanja vlažnosti zraka, te je mjerena promjena dimenzije i mase drvocementog kompozita prije i poslije vlaženja i sušenja. Mjerenja su provedena u laboratoriju koristeći otporničku metodu određivanja temperature rosišta, sušionik i mikrometar. U eksperimentalnom dijelu ovoga rada konstruirana je aparatura za određivanje temperature rosišta na temelju otporničke metode određivanja temperature rosišta, tako što se preko optičkog senzora CNY70 pratila promjena otpora na detektoru senzora. Zatim su mjerene dimenzije i drvocementnog kompozita prilikom sušenja. Eksperimentalni podaci za određivanje temperature rosišta potvrdili su ispravnost aparature zbog izrazitog poklapanja rezultata relativne vlažnosti, RH s očitanim vrijednostima na higrometru. Kod ispitivanja promjena mase i dimenzija kompozita, podaci za praćenje promjene mase utočnjeni su prema modelu jednofaznog eksponencijalnog opadanja: y=A1*e^(-x/t1)+yo, te je uočljiva poveznica početnih dimenzija kompozita sa promjenom mase i količinom apsorbirane vlage. Dimenzijske promjene ovisne su o debljini drvocementnog kompozita, što ima utjecaj na njegova svojstva.

Abstract (english)

The change in the dimensions of the wood-cement composite, which takes places during drying and wetting is an extremely important due to the application of the wood-cement composite. In this work, the dew point temperature was determined in order to establish the precision of the hygrometer in determining air humidity, and the change in the dimensions and mass of the wood-cement composite before and after drying and wetting process. The measurements were carried out in the laboratory using the resistance method for determining the dew point temperature, the dryer and a micrometar. In the experimental part, an apparatus for determining the dew point temperature was constructed based on the resistive method of determining the dew point temperature, by monitoring the resistance change on the sensor detector via the CNY 70 optical sensor. Then the dimensions and mass of the wood-cement composite were measured during drying process. Eksperimental data for determining the dew point temperature confirmed the precision of the apparatus due to the remarkable accuracy in results of relative humidity in comparison to the values detected by the hygrometer. When testing the changes in mass and dimensions of the composite, the dana for monitoring the change in mass were modeled according to one-phase exponential decay model: y=A1*e^(-x/t1)+yo, and there is a noticable link between the initial dimnesions of the composite and the change of mass and amount of absorbed moisture. Dimensional changes are depend on the thickness of the wood-cement composite, which has an impact on its properties.

• Keywords: drvocementni kompozit; vlažnost zraka; rosište
• Keywords (english): wood-cement composite; air humidity; dew point
• Language: croatian
• URN:NBN: urn:nbn:hr:149:729929
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-11-24 12:33:56