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Conventional motion mechanisms in adaptive skins require rigid kinematic mechanical systems that require sensors and actuation devices, hence impeding the adoption of zero-energy buildings. This paper aims to exploit wooden responsive actuators as a passive approach for adaptive facades with dynamic shading configurations. Wooden passive actuators are introduced as a passive responsive mechanism with zero-energy consumption.

The study encodes the embedded hygroscopic parameters of wood through 4D printing of wooden composites as a responsive wooden actuator. Several physical experiments focus on controlling the printed hygroscopic parameters based on the effect of 3D printing grain patterns and infill height on the wooden angle of curvature when exposed to variation in humidity. The printed hygroscopic parameters are applied on two types of wooden actuators with difference in the saturation percentage of wood in the wooden filaments specifically 20% and 40% for more control on the angle of curvature and response behavior.

The study presents the ability to print wooden grain patterns that result in single and double curved surfaces. Also, printing actuators with variation in infill height control each part of wooden actuator to response separately in a controlled passive behavior. The results show a passive programmed self-actuated mechanism that can enhance responsive façade design with zero-energy consumption through utilizing both material science and additive manufacturing mechanisms.

The study presents a set of controlled printed hygroscopic parameters that stretch the limits in controlling the response of printed wood to humidity instead of the typical natural properties of wood.

To investigate the effects of acetylation process as a chemical treatment method to improve the dimensional stability of wood, or as a pre‐treatment step to enhance the dimensional stability of wood by impregnates.

Esterification of two species of wood were carried out by vapour and liquid phase acetylation processes. With the vapour phase acetylation process, wood with different acetyl contents were obtained by changing the length of time of treatment. With the liquid phase acetylation, different acetyl content were obtained by changing the acetylating mixture or by activating wood with acetic acid for different periods of time and at different temperatures prior to the acetylation processes. The acetyl content and the conditions of impregnation improving the dimensional stability were modelled and optimised. The success of acetylation process for improving the affinity of wood towards the impregnation was also demonstrated.

Vapour phase acetylation process was preferable over liquid phase acetylation for improving both water resistance and dimensional stability of wood species examined. Liquid acetylating of wood, as a pre‐treatment step enhanced the effect of impregnates, especially the linseed oil to improve relevant wood properties. The greater improvement was obtained at 3 h impregnation time and 190°C curing temperature for 1 h.

Despite the success in improving the affinity of wood species to novolac by pre‐acetylation, increasing the curing time and curing temperature led to deterioration of the water resistance and dimensional stability.

Pre‐acetylation of the wood provided a practical solution to rendering the natural wood greater water resistance property using commercial impregnates.

The method for acetylation of wood prior to impregnation was novel and could be used for inhibiting wood against moisture absorption during storage.

Studies the treatment of wood‐processing waste using different impregnants as a tool for improving its water‐resistance properties, in order to achieve a reduction in the damage to building elements prepared from the treated wood waste when exposed to weather of relatively high moisture content. Applies different variables such as type of impregnant (synthetic resins or oils), concentration of impregnant, time of impregnation and thermal treatment. Obtains results which show that, generally, using a different concentration of synthetic resins (UF and novolac), or dry oils (motor oil and linseed oil) improved the water‐resistance property of wood waste, and that thermal treatment increases the improvement percentage as a result of impregnation. Also indicates that the optimum improvement in water resistance is attained when using 50 per cent linseed oil as the impregnant for an impregnation time of ten minutes, followed by hardening for three hours at 120°C.

Artworks made of hygroscopic materials, like wooden panel paintings, are susceptible to environmental conditions. Traditional panel paintings typically consist of a wooden panel coated with layers of gesso, paint and varnish. Due to environmental fluctuations, the gesso layer and the wood panel may respond differently to moisture changes, triggering potential fractures. The investigation of such phenomena is of high interest, but it is still scarcely studied by engineers.

The proposed study aimed to create a simplified 3D finite element model for paintings to identify environmental conditions that could exceed critical strain levels. A penny-shaped crack within the gesso layer was modelled and, after applying a given deformation, the strain energy density failure criterion was used to assess if the crack was in a critical state.

Various combinations of geometric parameters of the model were explored, and to save computational time and cost, machine learning algorithms (namely extreme gradient boosting machines and Gaussian process regression algorithms) were introduced. The analyses were carried out on different panel paintings 3D models obtained by varying the wooden species and the boundary conditions, for exploring a wide number of combinations.

Moreover, the integration of machine learning can potentially reduce the reliance on numerical simulations and offer new insights into the conservation of artworks, a field in which such tools are still scarcely exploited.

The purpose of this study is to quantify the vertical shrinkage rates and the mechanical strength of three-dimensional (3D) printed parts for a variety of wood-based materials for liquid deposition modeling.

The overall hypothesis was that a well-chosen combination of binders, fibers and fillers could reduce shrinkage in the Z dimension and increase compressive and flexural strength (DIN 52185, 52186). To test this assumption, eight sub-hypotheses were formulated. Mixtures of the ingredients were chosen in different ratios to measure the performance of prints. For time efficiency, an iterative heuristic approach was used – not testing all variations of all variables in even increments, but cutting off lines of testing when mixtures were clearly performing poorly.

The results showed that some mixtures had high dimensional accuracy and strength, while others had neither, and others had one but not the other. Shrinkage of 3D printed objects was mainly caused by water release during drying. An increase of the wood as well as the cement, sand, salt and gypsum content led to reduced vertical shrinkage, which varied between 0 and 23%. Compressive and flexural strength showed mixed trends. An increase in wood and salt content worsened both strength properties. The addition of fibers improved flexural, and the addition of cement improved compression strength. The highest strength values of 14 MPa for compressive and 8 MPa for flexural strength were obtained in the test series with gypsum.

This paper is an important milestone in the development of environmentally friendly materials for additive manufacturing. The potential of many ingredients to improve physical properties could be demonstrated.

This paper aims to provide a deeper understanding of using filling materials that are used to fill gaps in wooden objects, and their response to changes in the surrounding environment to evaluate wood gap fillers and choose the best material. As a wide variety of materials, but most of them were unsuitable for filler mixtures. Specific materials were used, which can adapt to changes in wood size in response to changes in humidity. This research discusses the results of experiments that were conducted to determine how gap fillers composed of glass microballoons, microcrystalline cellulose and paper pulp fills are mixed with Klucel G, Paraloid B-72 and methyl cellulose as binders, and respond in various conditions.

It requires using several scientific and analytical techniques to provide a deeper understanding of filling materials characterization, dimensional stability, their shrinkage and study mechanical properties.

The analytical study of filling gaps in wooden objects with different filling materials allowed defining that the main drawbacks of the examined gap fillers were low water resistance, poor dimensional stability upon drying, or exposure to water vapor or liquid water, and fragility. Two types of gap fillers with high mechanical properties and pH values similar to those of wood were found to be appropriate for application on wooden archaeological artifacts.

The importance of the experimental study was to determine suitable filling materials and provide the basic characteristics of filling materials reversibility, workability, dimensional stability, lack of shrinkage, drying, ability to take color and be shaped, stability with aging, compatibility with wood in terms of behavior with changing humidity and non-toxicity. Also, strength properties or their likelihood to deform easily allowing changes in the shape of the wooden object during the movement of wood, either of which may be desirable in specific circumstances.

Wood as a structural material has one feature which is unique among all structural materials; it is a crop which can be formed, whereas its competitors such as stone, brick, metal and plastic are all derived from exhaustible mineral sources.

In the last 25 years, we have seen a considerable increase in the use of new and unconventional methods for the remedial treatment of building defects. Some of the materials and techniques used have been employed long enough for an assessment to be made of their efficacy based on field experience. Some have only been evaluated by accelerated laboratory methods and do not yet have the full support of service records. Other products are declining in importance as a result of a ‘lack of approval’ by the independent bodies that pronounce on these matters.

IN wooden aeroplane manufacture, the technique to be adopted in the workshop is more or less a matter of the engineering experience gained by mistakes and disappointments.