Volume 21 Issue 3

Experimental particleboards were fabricated using Rhizophora spp. wood trunks, incorporating three different percentages of lignin and sodium alginate (0%, 3%, and 6%) as adhesives, as well as three different sample sizes of Rhizophora spp.: 0 to 104 µm, 105 to 210 µm, and 211 to 500 µm. The objective was to investigate the physical, morphology, chemical composition, and effective atomic number Z_eff of Rhizophora spp. particleboards incorporated with lignin and sodium alginate. The physical properties were studied using gravimetric method, thickness swelling, and water absorption tests. The fabricated particleboards had a suitable physical and radiological characteristic for tissue-equivalent phantom applications. The reduction in particle size and increase in adhesive content contributed to lower thickness swelling and water absorption. The density values fell within the specified range. According to scanning electron microscopy observations, increased adhesive content decreased the formation of voids in the structure of particleboards. The calculated effective atomic number further supported the suitability of material. Higher sodium alginate usage was found to be associated with an increase in sodium content. The sample A₆ with a particle size of 0 to 104 µm and 6% adhesive exhibited promising suitability for the fabrication of tissue-equivalent phantom.

Dimensional uniformity of wood chips is essential for stable delignification, and knife wear in a disc chipper is the primary factor that deteriorates chip quality. In this study, changes in particle size distribution (PSD) of pine wood chips were examined at three points along an industrial chip‑processing line, assessing the effects of knife sharpness, knife–anvil clearance, and transport and screening operations. Sharp knives combined with a narrow knife–anvil gap produced the lowest proportions of oversized and fine fractions, whereas progressive dulling significantly increased chip susceptibility to cracking during subsequent handling. The results indicated a need for more frequent knife maintenance and proper adjustment of the knife–anvil clearance to ensure stable chip quality under industrial operating conditions.

Biogas produced through the anaerobic digestion of organic biomass is a renewable energy source with significant potential to replace fossil fuels. However, impurities such as carbon dioxide, hydrogen sulfide, and water vapor reduce its calorific value and cause operational challenges. Upgrading is therefore essential to increase methane concentration and biogas quality. Among various upgrading technologies, adsorption using activated carbon offers a practical, low cost, and energy efficient alternative. Activated carbon derived from lignocellulosic biomass exhibits high surface area (up to 3000 m²/g), tunable pore structure, and resistance to moisture saturation, making it suitable for carbon dioxide and methane separation. Activation techniques, both physical (using carbon dioxide or steam) and chemical (using potassium hydroxide or phosphoric acid), significantly influence surface functional groups and pore distribution. Natural and synthetic binders such as bentonite clay, methyl cellulose, and polyvinyl alcohol can enhance mechanical strength and adsorption stability in humid conditions. This review considers the structure, activation, and adsorption mechanisms of biomass derived activated carbon for biogas purification. Future research directions include hybrid composite development, functional surface modification, and performance evaluation under industrial biogas conditions. Overall, activated carbon represents a sustainable and efficient adsorbent supporting the transition toward cleaner and low carbon energy systems.

The transition toward a circular economy has established biodegradable polymer composites as a critical platform for active food packaging. This review systematically examines the structural design, functional mechanisms, and application performance of natural biopolymer matrices, including polysaccharides and proteins. Physicochemical coupling among polymer-network architecture, interfacial interactions, and active-agent dispersion governs the integration of antimicrobial, antioxidant, gas-barrier, UV-shielding, moisture-regulating, and stimuli-responsive functions. Particular emphasis is placed on controlled mass transfer and release kinetics at active packaging interfaces. Active-agent delivery is governed by molecular diffusion, polymer-network relaxation, carrier structure, and microenvironmental triggers such as pH, humidity, and temperature, which collectively determine the effective concentration and duration of antimicrobial and antioxidant activity. These structure–release–function relationships are further evaluated in high-moisture foods, respiring fruits and vegetables, and low-moisture or lipid-rich products. In addition, this review discusses the major constraints on industrial translation, including the migration and regulatory compliance of intentionally and non-intentionally added substances, nanoparticle safety, environment-dependent biodegradation, life cycle impacts, and thermomechanical challenges associated with continuous processing. Future development should move beyond passive material substitution toward the integrated design of active and intelligent packaging, scalable manufacturing, food-specific performance validation, and multi-objective optimization of functionality, safety, cost, and end-of-life behavior.

Dependence curves for the kappa number of digester pulp (KN_DP), total pulp yield (TY), screened pulp yield (SY), and reject content in digester pulp (R_DP) as a function of the kappa number of screened pulp (KN_SP) were determined based on the results of several dozen kraft pulping tests of pine wood chips (Pinus sylvestris). These curves were then analyzed to assess whether their course could be used to distinguish qualitative types of pine kraft pulps and to determine the boundary values of the KN_DP, TY, SY, and R_DP indices for these types. Relationships of the form R_DP = f(KN_SP) were found to be particularly useful for this purpose. The identified types of pine kraft pulps and the limiting values of the parameters used to assess pulping process efficiency are presented in a table at the end of the paper.

Physical, mechanical, and quality characteristics of Uludağ fir (Abies nordmanniana subsp. bornmuelleriana) wood, which occurs naturally in Turkey, were determined. The effect of site classes (SCs) on these characteristics was investigated. Uludağ fir trees growing naturally in the Şerif Yüksel Forest Management District and belonging to different site classes (I, II, and III) were considered. The physical and mechanical properties of the test samples were determined in accordance with relevant standards, and differences between SCs were evaluated using statistical methods. SCs were found to have a statistically significant effect on the physical and mechanical properties of Uludağ fir wood (p<0.05). The highest performance in terms of physical and mechanical properties was generally observed in samples from Class II. Static quality (SQ) values ranged from 9.52 to 10.9, while dynamic quality (DQ) values ranged from 1.77 to 1.98. Based on DQ values, samples from all quality classes fell into the group of wood exhibiting high elastic properties; based on SQ values, they were classified as high-quality wood. The findings highlight the impact of SCs on the quality characteristics of Uludağ fir wood, providing important scientific data for quality-focused raw material selection, sustainable forest management, and the planning of wood usage areas.