scholarly journals Specific Dimensional Change Behavior of Laminated Beech Veneer Lumber (BauBuche) in Terms of Moisture Absorption and Desorption

Fibers ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 47
Author(s):  
Jan T. Benthien ◽  
Martin Riegler ◽  
Nick Engehausen ◽  
Martin Nopens
Keyword(s):  
Radial Direction ◽  
Building Materials ◽  
Moisture Absorption ◽  
Beech Wood ◽  
Wood Products ◽  
Sorption Behavior ◽  
Spring Back ◽  
Dynamic Vapor Sorption ◽  
Dimensional Changes ◽  
Precise Knowledge

Replacing greenhouse gas-intensive building materials with wood products from sustainable forestry contributes to the implementation of current climate conventions such as the Paris Agreement. Hardwood products, such as laminated veneer lumber made of beech (e.g., BauBuche), are an alternative to conventional building materials. For the application of wood products in the construction sector, a precise knowledge of the mechanical and physical properties is essential. Therefore, the aim of the present study was to investigate the sorption behavior and associated dimensional changes of the product BauBuche. This was done by applying a manual testing procedure (climatic chamber, balance and caliper) as well as a dynamic vapor sorption analyzer equipped with a camera. During initial moistening after production, due to the irreversible spring back (approximately 2 mm at 50 mm; i.e., 4%), Baubuche shows an extremely strong swelling in the radial direction. Once the maximum spring back is reached, Baubuche shows sorption behavior in the radial and tangential direction, which is comparable to that of solid beech wood in the radial direction. Consequently, the dimensional changes caused by moisture changes must be taken into account in the dimensioning of Baubuche components in order to avoid damage to building structures.

scholarly journals PECULIARITIES OF KINETICS OF THE COEFFICIENT OF THERMAL CONDUCTIVITY DEPENDING ON THE HUMIDITY RATE OF WALL BLOCKS MADE OF AGRICULTURAL WASTES

2019 ◽  
Vol 4 (10) ◽  
pp. 19-28 ◽  
Author(s):  
А. Должонок ◽  
A. Dolzhonok ◽  
А. Бакатович ◽  
A. Bakatovich
Keyword(s):  
Thermal Conductivity ◽  
Building Materials ◽  
Moisture Absorption ◽  
Coarse Aggregate ◽  
Sustainable Use ◽  
Agricultural Wastes ◽  
Hygroscopic Moisture ◽  
Relative Air Humidity ◽  
Coefficient Of Thermal Conductivity ◽  
Kinetics Of

The article considers the prospect of plant wastes usage as aggregates while constructing new building materials in the form of wall blocks. The results of the research on water absorption of the wall blocks at the relative air humidity of 97 % are presented. The kinetics of change in humidity and the coefficient of thermal conductivity of the blocks with the rye and buckwheat straw coarse aggregate, and also the blocks with fine coarse aggregate of flax boon and atomized buckwheat are analyzed. Empirical dependences of the coefficient of thermal conductivity on the rate of humidity of wall blocks are obtained from experimental observations. After the maximum rate of hygroscopic moisture absorption, the best indexes are recorded on the blocks made of flax and straw. The humidity rate of the composite does not exceed 10,9 % with the increase of thermal conductivity up to 0.104 W/(m•°С). In the result of the research, the solution to the sustainable use of agricultural wastes to get environmental responsible building materials is proposed. Blocks can be are used in the erection of supporting and filler walls in one-story buildings and multistoried frame housing construction when filling exterior wall openings.

scholarly journals Torrefaction of Almond and Walnut Byproducts

2021 ◽  
Vol 9 ◽  
Author(s):  
Zach McCaffrey ◽  
Lennard Torres ◽  
Bor-Sen Chiou ◽  
Saulo Rocha Ferreira ◽  
Luiz Eduardo Silva ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Moisture Absorption ◽  
Calorific Value ◽  
Dynamic Vapor Sorption ◽  
Energy Applications ◽  
Thermochemical Process ◽  
Heat Treated ◽  
The Us ◽  
Torrefied Biomass ◽  
Different Temperatures

While the US nut industry is growing, markets for nut by-products, particularly nutshells and tree prunings, have not kept pace. Torrefaction is a thermochemical process used to improve physicochemical properties of biomass for energy and other applications. The goal of the paper was to characterize the effects of a range of torrefaction conditions on the properties of nut by-product feedstock. The process consists of thermal treatment of biomass at a temperature between 200 and 300°C in the absence of oxygen, where final material properties of the torrefied biomass depend on the temperature, heating rate, and residence time. In general, torrefied biomass exhibits higher hydrophobicity and calorific value with reduced moisture absorption compared to untreated biomass, making it an ideal fuel source for energy applications compared to raw biomass. In this study, almond shells of soft, semi-soft, and hardshell varieties, as well as walnut shells and almond wood, were torrefied at two different temperatures (230 and 290°C) and three different residence times (20, 40, and 60 min) in order to characterize the physicochemical properties. The thermal behavior of raw and heat-treated biomass was investigated by TGA analysis, elemental analysis, pH, helium pycnometry, FTIR spectroscopy, and dynamic vapor sorption analysis.

A large-scale test set-up for measuring VOC emissions from wood products under laboratory conditions in simulated real rooms

Holzforschung ◽  
2015 ◽  
Vol 69 (4) ◽  
pp. 457-462 ◽  
Author(s):  
Eva Höllbacher ◽  
Cornelia Rieder-Gradinger ◽  
Daniel Strateva ◽  
Ewald Srebotnik
Keyword(s):  
Large Scale ◽  
Building Materials ◽  
Wood Products ◽  
Test Set ◽  
Voc Emissions ◽  
Laboratory Conditions ◽  
Volatile Organic ◽  
Scale Test ◽  
Set Up ◽  
Realistic Data

Abstract A large-scale test set-up was designed to evaluate the volatile organic compound (VOC) emissions of building materials in a real room situation but under laboratory conditions. Two model rooms (ModR) with a volume of 30 m3 each were constructed of the wood-based building materials X-lam and OSB, respectively. Temperature and relative humidity (RH) inside the ModR were kept in a range of 21°C–25°C and 45%–55% RH. VOCs were collected at 13 different times over a period of 23 weeks, and the total VOC (TVOC) concentration was calculated from GC/MS data. Results were quantified as toluene equivalents (TE). In the X-lam-ModR, the TVOC concentration decreased by 64% over the whole measurement period from 115 to 41 μg m-3 TE. Terpenes were the most abundant substance group and accounted, on average, for 80% of the TVOC concentration. In the OSB-ModR, the TVOC concentration decreased by 72% from 443 to 124 μg m-3 TE. Aldehydes showed the highest concentrations, accounting, on average, for 52% of the TVOC, while 38% were terpenes. The results show that this type of test provides realistic data for the praxis.

scholarly journals Effects of Shellac Treatment on Wood Hygroscopicity, Dimensional Stability and Thermostability

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 881
Author(s):  
Mihaela Liu ◽  
Guanglin Xu ◽  
Jianan Wang ◽  
Xinwei Tu ◽  
Xinyou Liu ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Moisture Absorption ◽  
Morphological Characteristics ◽  
Treated Wood ◽  
Wood Products ◽  
Control Group ◽  
Water Repellent ◽  
Thermoplastic Resin ◽  
Weight Percentage ◽  
Thermogravimetric Curve

Dimensional stability proves to be an important factor affecting the quality of wooden products. As a sort of crude and thermoplastic resin, shellac excreted by lac insects demonstrates water-repellent and environmental-friendly features. The research impregnated shellac with wood at room temperature and with a vacuum-pressure procedure. Efforts were made to examine how shellac treatment affected the dimensional stability, moisture absorption, chemical structure, thermostability, as well as morphological characteristics of wood. Results indicated that shellac treatment was a type of efficient solution useful in the enhancement of the dimensional stability of wood. Shellac solution had good permeability in the wood, and the weight percentage gain reached 13.01% after impregnation. The swelling coefficients of treated wood in the tangential and radial directions decreased by 20.13% and 24.12%, respectively, indicating that impregnation could improve wood dimensional stability. The moisture absorption of shellac-treated wood was reduced by 38.15% under 20 °C and 65% relative humidity. Moreover, shellac treatment significantly modified wood structure, although there were no drastic changes in the spectra. Specimens for shellac treatment ran across two decomposition peaks at 350 and 390 °C, and specimens in the control group saw one more common derivative thermogravimetric curve when the sharp peak approached 355 °C. After impregnation of shellac into wood, the shellac blocked pits and hardened on the intrinsic layer of the wood for fear of hygroscopicity. The practice was applicable to a variety of wood products, such as buildings, furniture, and landscape architecture.

scholarly journals Wood Properties Characterisation of Thermo-Hydro Mechanical Treated Plantation and Native Tasmanian Timber Species

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1189
Author(s):  
Michelle Balasso ◽  
Andreja Kutnar ◽  
Eva Prelovšek Niemelä ◽  
Marica Mikuljan ◽  
Gregory Nolan ◽  
...  
Keyword(s):  
Mass Loss ◽  
Wood Properties ◽  
High Water ◽  
Radiata Pine ◽  
Wood Products ◽  
Timber Species ◽  
Final Thickness ◽  
Dimensional Changes ◽  
Commercially Important ◽  
Shining Gum

Thermo-hydro mechanical (THM) treatments and thermo-treatments are used to improve the properties of wood species and enhance their uses without the application of chemicals. This work investigates and compares the effects of THM treatments on three timber species from Tasmania, Australia; plantation fibre-grown shining gum (Eucalyptus nitens H. Deane and Maiden), plantation saw-log radiata pine (Pinus radiata D. Don) and native-grown saw-log timber of the common name Tasmanian oak (which can be any of E. regnans F. Muell, E. obliqua L’Hér and E. delegatensis L’Hér). Thin lamellae were compressed by means of THM treatment from 8 mm to a target final thickness of 5 mm to investigate the suitability for using THM-treated lamellas in engineered wood products. The springback, mass loss, set-recovery after soaking, dimensional changes, mechanical properties, and Brinell hardness were used to evaluate the effects of the treatment on the properties of the species. The results show a marked increase in density for all three species, with the largest increase presented by E. nitens (+53%) and the smallest by Tasmanian oak (+41%). E. nitens displayed improvements both in stiffness and strength, while stiffness decreased in P. radiata samples and strength in Tasmanian oak samples. E. nitens also displayed the largest improvement in hardness (+94%) with respect to untreated samples. P. radiata presented the largest springback whilst having the least mass loss. E. nitens and Tasmanian oak showed similar dimensional changes, whilst P. radiata timber had the largest thickness swelling and set-recovery due to the high water absorption (99%). This study reported the effects of THM treatments in less-known and commercially important timber species, demonstrating that the wood properties of a fibre-grown timber can be improved through the treatments, potentially increasing the utilisation of E. nitens for structural and higher quality timber applications.

The effect of ionic liquid and superbase pre-treatment on the spring-back, set-recovery and Brinell hardness of surface-densified Scots pine

Holzforschung ◽  
2020 ◽  
Vol 74 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Benedikt Neyses ◽  
Olov Karlsson ◽  
Dick Sandberg
Keyword(s):  
Ionic Liquid ◽  
Scots Pine ◽  
Brinell Hardness ◽  
Wood Products ◽  
Densified Wood ◽  
Crystalline Cellulose ◽  
Control Group ◽  
Densification Process ◽  
Spring Back ◽  
Pre Treatment

AbstractCompressing the surface of sawn timber results in a substantial increase in hardness, and this opens up new market opportunities of using low-density timber species as the raw material for high-value wood products. Unfortunately, widespread commercialisation is hindered by the lack of an industrially viable surface densification process, the major obstacle being the set-recovery (SR) of the densified wood cells upon exposure to moisture. Our hypothesis is that partial dissolution of the crystalline cellulose during densification will largely prevent the SR of densified wood. We therefore evaluated the effect of ionic liquid (IL) or organic superbase pre-treatment on the elastic spring-back (SB), SR and Brinell hardness (HB) of surface-densified wood. Specimens of Scots pine were treated with solutions of ILs or superbases, and then densified in a hot press at temperatures between 200°C and 270°C. The SR was reduced from 90% for the control group to only about 10% for the treated materials. The treated and densified specimens exhibited a higher HB than their untreated and densified counterparts. The method presented in this study is a precursor to the development of a continuous densification process adapted for an open system. Further studies are needed to understand the underlying mechanisms of the pre-treatment.

Zeolite Crystal Layers Coupled To Piezoelectric Sensors: Molecular Recognition Demces

1991 ◽  
Vol 233 ◽  
Author(s):  
Yongan Yan ◽  
Thomas Bein
Keyword(s):  
Frequency Response ◽  
Sorption Isotherms ◽  
Gold Surface ◽  
Liquid Nitrogen Temperature ◽  
Sorption Behavior ◽  
Dynamic Vapor Sorption ◽  
Self Assembled Monolayer ◽  
Recognition Mechanism ◽  
Quartz Crystal Microbalances ◽  
Zeolite Crystals

ABSTRACTMicroporous zeolite crystals were successfully coupled onto the gold electrodes of quartz crystal microbalances (QCM). A self-assembled monolayer of thiol-alkoxysilane coupling agent on the gold surface was used as the Interfacial layer to promote adhesion of the zeolite crystals to the QCM. The resulting, densely packed single layers of zeolite crystals were stable to at least 625 K. Transient sorption behavior of organic vapor pulses, dynamic vapor sorption isotherms and nitrogen sorption isotherms at liquid nitrogen temperature were examined to characterize the zeolite-coated QCMs. Depending on the type of zeolite coating, the resonance frequency response to vapor pulses could be increased up to 500-fold compared to the bare QCM. The regular micropores (0.3–0.8 nm) of the QCM-attached zeolite crystals were found to control molecular access into the extensive intrazeolite volume. Selectivity of the frequency response in excess of 100:1 toward molecules of different size and/or shape could be demonstrated. An additional recognition mechanism based upon intrazeolite diffusion rates was also established.

Eco-labeled wood products in the U.S. residential construction industry: Architects’ awareness and usage of certified wood and green building programs

2014 ◽  
Vol 90 (05) ◽  
pp. 605-613 ◽  
Author(s):  
Tait Bowers ◽  
Indroneil Ganguly ◽  
Ivan Eastin
Keyword(s):  
Building Materials ◽  
Green Building ◽  
Design Guidelines ◽  
Wood Products ◽  
Residential Construction ◽  
Efficient Design ◽  
Renewable Materials ◽  
Environmental Friendliness ◽  
Certified Wood ◽  
The U.S

The use of environmentally friendly building materials has experienced slow growth within the residential construction market due to higher cost and low availability of certified wood. The development of green building programs (GBPs) marked the beginning of the effort to adopt energy-efficient design guidelines and utilize eco-friendly renewable materials in structures. These programs were targeted at reducing environmental impacts by integrating eco-friendly materials into the design and construction of buildings, including promoting the use of environmentally certified wood products (ECWPs) harvested from sustainably managed forests. This research was designed to determine which attributes influence architects’ decisions to use environmentally certified wood products in residential construction projects and how this might influence their perceptions and use of green building programs. The results indicate that architects who have participated in a GBP were more likely to have used ECWPs. The material attributes that influence architects’ selection of materials are mainly related to economics and function as opposed to environmental friendliness. These results will help to inform and broaden the understanding of issues that influence the adoption and utilization of environmentally certified wood products, and identify some of the factors that can contribute to their continued growth in the U.S. marketplace.

Oregon design professionals views on structural building products in green buildings: implications for wood

2011 ◽  
Vol 41 (2) ◽  
pp. 390-400 ◽  
Author(s):  
Chris Knowles ◽  
Christine Theodoropoulos ◽  
Corey Griffin ◽  
Jennifer Allen
Keyword(s):  
Structural Material ◽  
Environmental Performance ◽  
Building Materials ◽  
Material Selection ◽  
Green Building ◽  
Wood Products ◽  
Forest Stewardship Council ◽  
Rating Systems ◽  
Forest Stewardship ◽  
Group Interviews

Buildings have been shown to have impacts on the environment. Consequently, green building rating systems have become a tool to help reduce these impacts. The objectives of this study were to identify gaps in information and access to green building materials as viewed by Oregon design professionals. The scope was limited to the major structural materials: concrete, steel, and wood. This article focuses on the results unique to wood products. Information was collected through group interviews. Each group was composed of professionals representing different aspects of material selection and construction of different scales. The results showed that structural material selection is driven by building code, cost, and building performance requirements. The environmental performance of the material was not considered. However, once the material was selected, designers tried to maximize environmental performance. The results showed that green building rating systems do not influence structural material selection, and interviewees noted that there is room for improvement in this area. Respondents had a positive view of wood and a strong desire to use more wood, particularly Forest Stewardship Council certified wood. Wood was viewed as the most sustainable structural material available. However, there were some concerns about wood products, with formaldehyde emissions being the most significant.

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