Wood Layers Research Articles

Maintaining Canopy Density under Summer Stress Conditions Retains PSII Efficiency and Modulates Must Quality in Cabernet Franc

Shoot topping and other summer grapevine management practices are considered crucial for producing high-quality wine. However, in recent years, climate change is increasing the need to reassess these strategies, as excessive radiation and high temperatures can negatively impact canopy functionality and berry quality. Indeed, it has been hypothesized that limiting summer vegetative pruning may protect the bunch, via shading, and the leaf by maintaining a more favorable environment for leaf functionality (e.g., lower VPD, reduced high light stress) owing to a denser canopy. In this work, a series of canopy manipulation treatments (shoot topping vs. long-shoot bundling; secondary shoot trimming vs. untrimmed) were tested in a replicated factorial block design over two seasons in field-grown grapevine plants (cv. Cabernet Franc grafted in SO4). Overall, treatments in which secondary shoot removal and/or shoot topping were not applied produced a higher canopy area, increased pruning wood and leaf layers, and had a higher Fv/Fm on warm days when compared to pruned canopies. These were associated with a year-dependent modulation of quality parameters of the must in which long-shoot bundling treatment, overall, produced the highest polyphenol and anthocyanin contents and must acidity. Our data provide evidence of a potential usefulness of preserving dense canopies under high temperature – high irradiance conditions with desirable effects on leaf photosynthesis and must quality when long-shoot bundling was applied.

Wood Scrolls as Highly Efficient All‐Day Steam Generators

AbstractA novel all‐day evaporator in the form of a scroll is developed by rolling a thin layer of wood. Two different wood layers are used to fabricate a wood scroll with diagonal natural water channels (d‐WS) and a wood scroll with parallel natural water channels (p‐WS). Because only diagonal channels allow water transport across the wood layer, d‐WS exhibits good lateral water transport, whereas p‐WS exhibits poor lateral water transport. The gap channels (i.e., spaces between the overlapping wood layers) facilitate vertical water transport in both d‐WS and p‐WS. The synergistic effect of the gap channels and diagonal channels in d‐WS allows for a uniform water flow and sufficient water transport to the top and side surfaces, thus simultaneously increasing evaporation performance and salt resistance. The total evaporation rate of water of d‐WS is 9.08 kg m−2 h−1 in the absence of wind, which increases to 37.95 kg m−2 h−1 in the presence of 2 m s−1 wind. These evaporation rates are among the highest values ever reported under similar conditions. The evaporation rate of d‐WS does not deteriorate even after 5 d, demonstrating the possibility of long‐term operation.

Scalable, efficient piezoelectric wood nanogenerators enabled by wood/ZnO nanocomposites

The need for sustainable development creates opportunities for biomass-based materials design toward piezoelectric mechanical energy harvesting. Wood is promising due to its hierarchical, porous structure. Here, piezoelectric nanogenerators (PENGs) were prepared through nanostructure-controlled zinc oxide (ZnO) growth inside the outer wood layers of veneers. Mechanisms for formation of various ZnO nanostructures in wood are analyzed. Controlled morphologies of nanoparticles, nanorods, nanowires, and nanoflakes were realized and characterized by field emission-scanning electron microscopy (FE-SEM) and small angle x-ray scattering (SAXS), allowing tunable piezoelectric output. Nanostructures with higher aspect ratios i.e. nanorods and nanowires resulted in higher voltage during cyclic loading. An optimum voltage of 1.3–1.4 V was obtained with wood/ZnO nanowire or nanorod composites at a force of ≈8 N. The current output is in the range of 0.85–11 nA, which could be scaled up to ∼130 nA with a larger area device. When mounted in shoe soles, these wood/ZnO PENGs generated 1–4 V from walking/jogging motions. The hydrothermal growth method is scalable, which facilitates practical applications.

Tree Bark: A Surprising and Diverse Reservoir for Water

Bark is the outside layer of wood that all trees have. Bark protects trees from harsh environmental conditions including weather, pests, disease, and damage from hungry animals. Just like leaves, bark is different across species. Some trees have thick, rough bark while others have thin, smooth bark. When it rains, bark acts like a sponge and absorbs water. Some trees have bark with large pore spaces that make it easy to absorb rain water quickly. Other trees have bark with smaller pore spaces, which absorb water slowly. Each tree species has a maximum storage capacity of water that can be held in the bark. In fact, some mature trees can store more than 100 L of water in their bark—that is about as much water as you would use in a 10-min shower! In this way, bark influences the water cycle of individual trees and entire forests.

Formalized model of polarization of a biopolymer composite in an inhomogeneous temperature field

The article presents a formalized model built according to classical thermodynamics that describes the polarization mechanism in a layer of wood in an inhomogeneous temperature field. The model provides the basis for a computational experiment to determine the parameters of the kinetics of the wood microstructure based on the measurement data of the potential difference that occurs in a sample in a non-uniform temperature field.

Modeling of Wood Surface Ignition by Wildland Firebrands

The probability of structural ignition is dependent both on physical properties of materials and the fire exposure conditions. In this study, the effect of firebrand characteristics (i.e., firebrand size, number of firebrands) on wood ignition behavior was considered. Mathematical modeling and laboratory experiment were conducted to better understand the conditions of wood ignition by a single or group of firebrands with different geometry. This model considers the heat exchange between the firebrands, wood layer and the gas phase, moisture evaporation in the firebrands and the diffusion gases of water vapor in the pyrolysis zone. In order to test and verify the model, a series of experiments to determine probability and conditions for ignition of wood-based materials (plywood, oriented strand board, chipboard) caused by wildland firebrands (pine twigs with a diameter of 6–8 mm and a length of 40 ± 2 mm) were conducted. The experiments investigated the firebrand impact on the wood layer under different parameters, such as firebrand size and quantity, wind speed, and type of wood. The results of experiments showed that the increase in wind speed leads to the increase in probability of wood ignition. Based on the received results, it can be concluded that the ignition curve of wood samples by firebrands is nonlinear and depends on the wind speed and firebrand size as well as their quantity. At the same time, there is no ignition of wood samples in the range of wind speed of 0–1 m/s. The ignition of wood is possible with a decrease in the distance between the firebrands with a decrease in the firebrand length. This result agrees more closely with the model.

Mathematical model of the stress-strain state of a rod with an inhomogeneous layered structure

The stress-strain state (SSS) of a rod with an inhomogeneous layered structure is considered. On the basis of a brief review and analysis of the current state of research of rod systems, the relevance of the study of the SSS of layered-heterogeneous wooden structures is substantiated, taking into account the presence of different resistance of layers to tension and compression. On this basis, the authors solve the problem of determining the SSS of layered-heterogeneous wooden rods in creep conditions, where factors such as humidity and temperature, as well as the difference in the resistance of wood layers to stretching and compression are taken into account. When solving the problem, the mechanical-sorption creep of wood is also taken into account.

Physical and Chemical Changes in Hydrothermally Modified Wood

In this study, the simulation of artificial conditions, containing various chemical additives similar to a bog environment, was hypothesised as a relatively short way to develop a more sustainable wood product with better properties. This study aimed to determine how hydrothermal treatment with different iron additives with and without tannic acid, performed at 100 °C for 75 h, changed the mass and density of wood of different tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Pseudotsuga menziesii (Mirb.) Franco, Juglans regia L., and Acer platanoides L.); total phenolic compounds in biobased solvents after the hydrothermal processing andiron concentration in different wood layers. We also aimed to determine the wood chemical composition using Fourier-transform infrared technique. The study results showed that the softwood samples were more susceptible to hydrothermal modification than the hardwood samples, indicated by minorly different intensities on infrared spectra. The FTIR results showed bands of hardwood and softwood samples which along with the spectral characterisation of the wood constituents, which can further be utilized for creating a larger FTIR spectral database of wood samples for their identification. The factors with the most significant effect on the hydrothermal modification were tannic acid and inorganic Fe3O2 salt, used as an additive. The results indicated the suitability of inorganic Fe3O2 salt and tannic acid combination applied in this type of modification, because a higher concentration of iron was distributed on the inner and intermediate sublayers of wood samples. The hydrothermal modification approach to anchor tannic acid–Fe macromolecules in wood shown in this study has promising capabilities and may attract interest in the field of wood protection against weathering.

Radial growth patterns of Siberian larch in plantations of the Republic Mari El

Based on the measurements of 83 wood cores, the main patterns of changes in the width of the early and late zones in the annual ring of Siberian larch trees (Larix sibirica Ledeb.), as well as their total radial growth indices in the conditions of the Republic of Mari El were identified. It was found that the width of the early wood zone varies in trees from 0.15 to 11.3 mm, late wood – from 0.05 to 4.15 mm, the proportion of latewood – from 1.2 to 82.8 %, and the annual growth indices - from 13 to 423 %. The main factor in the variability of the total width of the annual rings and the layer of early wood is the age of the trees, and the contribution of weather conditions and other unaccounted factors (noise) to the overall variance of the annual growth parameters is no more than 20 %. The variability of the total width of the annual ring also depends on their genotypic features, which determine up to 42.7% of the total variance of the parameter in some cenopopulations. In the dynamics of the growth indices of larch trees, despite the existing specifics of each cenopopulation, the general sharp decline in their values after the droughts of 1972 and 2010, as well as the alternation of the periods of growth and decline, is clearly distinguished.

An innovative resource‐efficient timber‐concrete‐composite ceiling system: Feasibility and environmental performance

AbstractTimber‐concrete composite (TCC) ceilings build on the idea of making use of the advantageous properties of both materials symbiotically. While concrete, as the upper layer, is used to absorb the compression forces, wood is used in the lower layer to absorb the tensile forces. Many systems have been developed with special attention paid to solutions with both a continuous concrete and wood layer. This article introduces a new system developed with the primary focus set on the most efficient material use by introducing a free space between the concrete and the wood layer using special vault shaped moldings. The first part of the paper contains an introduction including a short overview of different embodiments of TCC floor systems. The second part focuses on the design of the new system and gives an overview of the estimated structural performance. In the third part the environmental performance of the new system is discussed in comparison to chosen existing systems focusing at the the whole life‐cycle including a re‐use (A‐D).

Characteristics and possible formation process of ferromanganese beachrock in an intertidal zone of East China Sea influenced by buried ancient woods

The ferromanganese (FeMn) deposits could be found in many shallow water and deep-ocean places. Lots of studies have been performed to explore the occurrence, formation and economic value of FeMn nodules or crusts on the deep ocean floor. However, the occurrence and formation of FeMn beachrocks at the coastal zones has rarely been reported. In the present study, we collected two types of dendritic FeMn beachrock samples from an intertidal zone of Zhoushan Archipelago, East China Sea, where was significantly amended by an ancient wood layer formed during 5900–5600 cal. yr B.P. Then the microscale analysis including electron microprobe analyzer (EMPA), X-ray powder diffraction (XRD), and scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDS) were performed to study the microscale characteristics on these FeMn beachrocks. Combined with our previous studies, a possible formation process was proposed: (1) Buried ancient woods produced enough organic acids to accelerate the weathering of nearby bedrock via chemical or biological reactions; (2) The seepage water could be regarded as a bridge to connect the ancients woods and the intertidal zones, and large amounts of dissolved Fe2+ and Mn2+ can be transported to the sandy beach and intertidal zones; (3) Precipitation of insoluble FeMn oxides occurred with the involvement of microbial processes and direct inorganic chemical sorption under mixing of seepage water and seawater; (4) After that, these FeMn oxides would experience nucleation, crystallization growth, and then diagenetic process to form the FeMn beachrocks. The present study spotted a light on the microscale features, formation process and biogeochemical cycling of nearshore/coastal diagenetic Fe-Mn deposits.

Comparison of different modeling methods toward predictive capability evaluation of the bonding strength of wood laminated products

The main aim of this study is usability evaluation of different approaches, including response surface methodoloy, adaptive neuro-fuzzy inference system, and artificial neural network models to predict and evaluate the bonding strength of glued laminated timber (glulam) manufactured using walnut wood layers and a natural adhesive (oxidized starch adhesive), with respect to this fact that using the modified starch can decrease the formaldehyde emission. In this survey, four variables taken as the input data include the molar ratio of formaldehyde to urea (1.12–1.52), nanocellulose content (0%–4%, based on the dry weight of the adhesive), the mass ratio of the oxidized starch adhesive to the urea formaldehyde resin (30:70–70:30), and the press time (4–8 min). In order to find the best predictive performance of each selected evaluation approach, different membership functions were used. The optimal results were obtained when the molar ratio, nanocellulose content, mass ratio of the oxidised starch, and press time were set at 1.22, 3%, 70:30, and 7 min, respectively. Based on the performance criteria including root mean square error (RMSE) and mean absolute percentage error (MAPE) obtained from the modeling of response surface methodology, adaptive neuro-fuzzy inference network, and artificial neural network, it became evident that response surface methodology could offer a better prediction of the response with the lowest level of errors. Beside, artificial neural network and adaptive neuro-fuzzy inference system support the response surface methodology approach to evaluate bonding strength response with high precision as well as to determine the optimal point in fabrication of laminated products.

Hardened wood as a renewable alternative to steel and plastic

Hardened wood as a renewable alternative to steel and plastic

Micro-oxygenation level as a key to explain the variation in the colour and chemical composition of wine spirits aged with chestnut wood staves

A deep knowledge of oxygenation level effect on wine spirits' ageing is imperative to understand ageing chemistry and to select the most suitable technological option towards quality and sustainability. Following two articles on the same trial, this work focused on colour, total phenolic index (TPI) and basic chemical characteristics of a wine spirit aged in 50 L demijohns with chestnut wood staves together with three micro-oxygenation (MOX) levels. Chromatic characteristics and TPI were monitored over time (8–365 days) while sensory colour, alcoholic strength, acidity, pH and dry extract were assessed at the end of ageing. Results showed that stronger oxygenation promoted significantly faster colour evolution (lower lightness, higher chroma, red, yellow and brown hues) and higher TPI than mild and intermediate oxygenation until 60 days, probably by favouring the leaching of outer wood layers and extraction/degradation of tannins. No significant differences were found between these ageing modalities at 365 days. Outcomes suggest that the stronger MOX is the most suitable modality in terms of quality and sustainability. Significant differences between wine spirits resulting from MOX and control modality (slower colour evolution, lower TPI and dry extract) confirms the oxygen pivotal role in wine spirit's ageing, particularly in the colour evolution.

DEVELOPMENT OF WOOD GRINDING. 3. FURTHER TESTING OF GRINDING MODELS

"The study is the continuation of a sequence of works devoted to describing the mechanisms occurring during stone grinding of wood. This part was aimed at further testing of pressurised grinding of spruce wood, which was conducted under controlled laboratory conditions. Testing of the developed theoretical model for power ratio (Pc/Pt) versus energy specific production (Ġw/Pt) produced linears for data representing constant wood moisture content. However, the linears showed almost identical results for fresh woods, and also for drier wood, e.g. wood containing saturated fibres and air-dried wood, although one would expect some differences due to the widely varying constant moisture, from 65% to 15% moisture content. Simplification of the model resulted in (cw + X cm) ΔTp-w ≈ Pt / Ġw, and it led to specific linears, when the members as such were correlated between themselves at several constant wood moisture contents. The results were briefly as follows. Increasing wood feed rate – 0.7, 1.0 and 1.3 mm/s – decreased the specific energy requirement, while increased stone surface speed – 20 and 30 m/s – increased it. The left-hand member or the “X-factor” as named in this context, correlated with the right-hand member or the specific energy requirement and resulted in declining linears. The lower the wood moisture content – 65, 58, 44, 28 and 15% – the smaller was the linear declination, and also the difference due to stone surface speed. The application of an energy balance could be useful in searching for a working wood grinding model. Such a model would enable critical examination of wood grinding conditions. Also, it would help understanding the mechanism of various factors, such as grinding parameters, wood properties and stone burr and sharpness. It seems that there are factors that are not known well enough for further development of grinding. Shower water flow and temperature affect the stone surface temperature as known, but their significance for the energy balance or grinding mechanism are not known. Also, the thin film of pulp slurry between the stone surface and the heat activated wood layer is evidently a significant factor that is connected to the local energy transfer. "

Properties of wood-based composites manufactured from densified beech wood in viscoelastic and plastic region of the force-deflection diagram (FDD)

Abstract It is still little or no knowledge about the properties of layered wood-based composites and nonwood components in the viscoelastic and plastic region of the force-deflection diagram (FDD). The properties of composites in this area are influenced by several factors such as the composition of the layered composite, the method of modification of the individual layers, the type of adhesive used, etc. This paper focuses on the analysis of the effect of the thickness of individual layers (5 and 9 mm) of beech wood (Fagus sylvatica L.), modification of these layers with different degrees of densification (10, 20, 30, and 40%) and the type of the nonwood component (carbon and high-strength glass fibers) used to reinforce the layered composite on the properties of materials in the plastic region of the FDD. The paper describes the impact of selected factors and those interactions behavior of the tangent modulus in the whole FDD. This is the first study that describes the development of layered wood-based composites and nonwood components in the viscoelastic and plastic region and analyzes the impact of most imported types of modifications on the characteristics in the viscoelastic and plastic regions.

Characterizing the Layer Structures of the Lacquerware From the Palace Museum by Terahertz Imaging in Reflection Geometry

Chinese lacquerware is an important invention of arts and crafts in China. In this study, Chinese lacquerware is characterized using terahertz reflectometric imaging. The lacquerware studied herein comprises an ornamental wood panel covered by multiple layers of lacquers to portray motifs. For characterizing lacquerware, a terahertz time-domain spectroscopic reflectometric imaging system is proposed. The role of the proposed terahertz imaging system in highlighting the interface between layers during stratigraphic buildup in reflection geometry is proved. The proposed system provides a universal method for assessing the structural information of lacquered objects in a contactless and non-invasive manner; moreover, it provides two-dimensional images, subsurface three-dimensional images, and stratigraphic images (b-scans) in a contactless and non-invasive manner. Using the proposed system, we examine the buried layers of the lacquerware, including faults in the wooden layer and damages in the lacquerware. Research shows the promising prospects of terahertz time-domain spectroscopic reflectometric imaging as a non-destructive detection technique suited to lacquerware.

High-Performance All-Bio-Based Laminates Derived from Delignified Wood

The need for renewable bio-based materials that could replace well-established synthetic composite materials is rapidly growing. For example, bio-based materials are increasingly used in applications where a lightweight design should be combined with sustainability and recyclability. However, it is often very challenging to directly transfer the excellent properties of biological materials to a product in a scalable and cost-efficient manner. In this study, we combined delignified wood layers (veneers) and a starch-based glue into bio-based high-performance composites. First, we investigated the ideal amount of starch-based glue between the layers to prevent delamination in the final composite. Then, we produced laminates in unidirectional, cross-ply, and quasi-isotropic configurations using wet processing. Laminates with tensile properties up to 40 GPa and 200 MPa in tensile stiffness and strength, respectively, were fabricated with a very high fiber volume content of up to 80%. The high fiber volume contents led to mechanical interlocks between neighboring fibers and made the need for an additional matrix unnecessary. The water-based laminate process is cost-efficient and scalable and additionally allows one to make full use of delignified wood’s formability by producing shaped parts for various applications.

CLT – material for the measure of the future

CLT – material for the measure of the future. CLT (cross laminated timber, X-Lam) is one type of engineered wood products. The first idea of CLT was presented in the seventies of the last century in Austria. Over the following years, the concept of cross-gluing wood was intensively developer in Europa, USA, Canada and China. Based on the literature data, this work presents history, structure, production process ,selected mechanical and physical parameters and applications of CLT. CLT is a wood panel product made from gluing together layers of solid-sawn lumber. The number of wooden layers is unpaired, most often 3, 5 or 7. Each layer consists of closely spaced and parallel boards. Adjacent layers are perpendicular to each other. The physical and mechanical properties of this product depend on many factors, e.g. number of layers and their thickness, the width and thickness of the boards in the layer, class of lumber, species of wood. Despite the fact that CLT is rather new material often used, especially in construction industry (both single-storey and multi-storey buildings). The short time of project implementation and their ecological character indicate that CLT is the material of the future in construction industry.

An investigation and comparison of tensile strength in Fiber Sandwiched Wood Composite (FSWC) materials subjected to axial loading

The demand of composite materials like Fiber Reinforce Polymer (FRP), Carbon Fiber Reinforce Polymer (CFRP) and Glass Fiber Reinforce Polymer (GFRP) are increasing rapidly in industrial use because the characteristics of these materials involving higher strength to weight ratio and least cost incorporates the researchers to make interest. Composite materials are helping the industries in combination with different materials to achieve the desired material properties. Now a days, these materials had taken a part of sheet metal in many aerospace industries. Carbon fabric or epoxy composite materials are used in various industries for manufacturing special purpose applications. To evaluate the material performance, it is necessary to understand their mechanical properties like tensile strength. The tensile strength is usually used to determine the tensile testing data for the quality assurance of materials. Fiber Sandwiched Wood Composite (FSWC) materials are prepared by sandwiching the layers of wood and fibers. The composite materials with wood lead to variation in tensile strength. In that event, some specimen was prepared using teak wood and fibers involving Carbon, Aramid, Jute, and Banana. The specimens were evaluated for tensile strength using Universal Testing Machine (UTM) as per the ASTM 3039 standards. The comparison had been made with plain teak wood having known properties. The hybrid layers of Carbon and Aramid Fibers with teak wood presented the higher value. A comparison had made of FSCM and plain Materials like teak wood and aluminium. The results shows that the Carbon Aramid hybrid composites have 2.65% more strength as compare to Teak Wood and 1.79% more than the Aluminium.