The effects of production technologies on the air permeability properties of cross laminated timber

In building envelope, the cross laminated timber (CLT) is often used as air barrier layer. The objective of this study was to evaluate the impact of production technologies such as edge bonding, different initial moisture content (MC) of lamination, and number of lamination layers (3 and 5) on the air-permeability properties of cross laminated timber. Air leakage and crack growth in CLT panels were measured after the panels were conditioned in environments with different relative humidity (RH) in progressive steps from humid to dry environments (RH 70%→ RH 50%→ RH 30%→ RH 10%). The test results showed that the most effective technologies for avoiding large crack growth and air leakages through panels were to use 5 layers of laminations with bonded edges. Overall, it can be recommended that for the production of CLT panels it is advisable to use primarily a larger number of layers, at least 5, for smaller growth of cracks on panel surfaces and thereby avoid air leakages during the time of use. The use of bonded edge technology helps to ensure the avoidance of possible air leakage threats, but in the long-term, this beneficial effect might decrease as bond layers may rupture or cracks may form in the middle of laminations

Change of Pressing Chamber Conicalness at Briquetting Process in Briquetting Machine Pressing Chamber

In this paper, we will present the impact of the conical shape of a pressing chamber, an important structural parameter. Besides the known impact of the technological parameters of pressing chambers, it is also very important to pay attention to their structural parameters. In the introduction, we present a theoretical analysis of pressing chamber conicalness. An experiment aimed at detecting this impact was performed at our institute, and it showed that increasing the conicalness of a pressing chamber improves the quality of the final briquettes. The conicalness of the pressing chamber has a significanteffect on the final briquette quality and on the construction of briquetting machines. The experimental findings presented here show the importance of this parameter in the briquetting process

Recovery of Metallic Materials from Printed Wiring Boards by Green Pyrolysis Process

Currently, the main options for the treatment of electronic waste are involved in reuse, remanufacturing, and recycling, as well as incineration and land filling. Recycling of e-waste can be broadly divided into three major steps: (a) disassembly: selectively disassembly, targeting on singling out hazardous or valuable components for special treatment, is an indispensable process in recycling of e-waste; (b) upgrading: using mechanical processing and/or metallurgical processing to up-grade desirable materials content, i. e. preparing materials for refining process; (c) refining: in the last step, recovered materials are retreated or purified by using chemical (metallurgical) processing so as to be acceptable for their original usage. To investigate an environmentally friendly process to recycle PWBs, the milled PWB powder samples with and without additives were pyrolyzed. Liquid, gas and solid products were achieved with different conversion fraction. PWB powders were pyrolyzed and in a thermo-gravimetric analysis, differential thermal analysis (TG/DTA) and exhausted gases were analyzed by mass spectrometer (MS). Analysis of the exhaust gases from the experiments using TG-DTA-MS showed that without CaCO3 additives poisonous gases such as C6H6 and HBr were produced which were adequately controlled if CaCO3 was added.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2432</p

Influence of interior layer properties to moisture dry-out of CLT walls

The objective of this study was to determine the maximum allowable initial moisture content (MC) for cross-laminated timber (CLT) walls having both exterior and interior thermal insulation. A laboratory test was conducted, for which four test walls with two different insulation solutions and two different MCs were built. Based on the test results, a simulation model was configured and simulations using the model were completed. The simulation results determined that the maximum allowable initial MC of the CLT panels was 17% for walls insulated additionally from inside with mineral wool and 15% for CLT wall assemblies insulated with polyisocyanurate (PIR). Based on these results, it was concluded that the allowable MC ranges between 8% and 16% for construction timber, and therefore, using a PIR board as interior insulation for CLT walls should be undertaken with caution given the very small margin for error in MC.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Control of Gas Emission During Pyrolysis of Waste Printed Wiring Boards

The pyrolysis of PWBs was investigated by a TG-DTA-MS furnace at 300-1173 K. the kinetics and the control of emitted gas during the pyrolysis of PWBs with and without chemical additives were studied. Moreover, the possibility of controlling the amount of toxic exhaust gases like HBr, C 6H 6, Br 2, Cl 2, HCl gas and recovering beneficial gaseous fuels like CH 4 and H 2 from pyrolysis process is discussed. the MS data for each PWB sample were examined as a function of temperature and particular m/z values could be associated with the mass loss steps in the TG data. the degradation of the organic material was characterized by m/z = 2, 16, 18, 28, 36, 44, 71, 78, 81, and 160. Fe 2O 3 was the best inhibitor of toxic HBr and CeHe when compared to Al 2O 3, CaO Y-zeolite and ZSM-5. Moreover, it had no significant effect on the valuable H 2 and CH 4 gas evolution. This selective inhibition of toxic gases while maintaining the valuable ones make Fe 2O 3 the best candidate among the investigated additives in controlling gas emissions from PWB pyrolysis process

Influence of hollow glass microspheres on the mechanical and physical properties and cost of particle reinforced polymer composites

Abstract. The goal of the study was to find a cost-effective composition of a particle reinforced composite that is light in weight but has sufficient mechanical properties. The matrix of the particulate composite is unsaturated polyester resin that is reinforced with alumina trihydrate particles. Part of the alumina trihydrate proportion was replaced with hollow glass microspheres to reduce weight and save costs. In order to find out the influence of the light filler on the physical and mechanical properties of composites, materials with different percentages of the light filler were prepared. Test specimens were cut from moulded sheets that were fabricated with vacuum assisted extruder. Tensile strength, indentation hardness measured with a Barcol impressor, and density were determined. Based on the experimental data a multi-criteria optimization problem was formulated and solved to find the optimal design of the material. Artificial neural networks and a hybrid genetic algorithm were used. The optimal solution is given as a Pareto curve to represent the distinction between the density and selected mechanical properties of the composite material. The composite material filled with 6% hollow glass microspheres showed 3% loss in the tensile strength and 26% loss in the surface hardness compared to the composition without the filler. The weight decreased by 13% compared with the initial composition. The addition of hollow glass microspheres did not lower the net value of the material, it increased 7%

Preliminary Study of the Influence of Post Curing Parameters to the Particle Reinforced Composite's Mechanical and Physical Properties

This study examines the effect of different post cure parameters to a polymer matrix particulate reinforced composite material. The goal is to evaluate the importance of different factors and to suggest a well-balanced post cure mode that supports the application of the material.<br />Polymer matrix composites are post cured at elevated temperature to increase the amount of cross linking to achieve better chemical and heat resistance and mechanical properties. Every material has an individual post cure process that depends from the raw materials. Post curing variables include temperature, duration of cure, the time between initial curing and post curing and temperature profile gradient.<br />There are several ways to determine the cure state of a polymer. It can be evaluated based on the mechanical and physical properties, residual styrene content, glass transition temperature, residual exotherm or solvent swelling test.<br /> For the determination of the suitable post cure parameters test slabs were casted and post cured with varying time and temperature. Glass transition temperature, residual exotherm, softening in ethanol, surface hardness, flexural strength and flexural modulus were determined. It is shown that the material should be cured at 60°C–80°C. With higher temperature and extended time of cure the glass transition temperature raises but the material becomes too brittle.<p>DOI: <a href="http://dx.doi.org/10.5755/j01.ms.18.3.2435">http://dx.doi.org/10.5755/j01.ms.18.3.2435</a></p