1. Enhancing wood sample preparation for SEM imaging : a detailed study of epoxy resin impregnation, cutting, sanding, and polishing for fragile and heterogeneous samplesRožle Repič, Maks Merela, Andreja Pondelak, Andrijana Sever Škapin, 2026, original scientific article Abstract: Accurate characterization of wood microstructure requires high-quality sample preparation, especially for degraded, mineralized, or embedded samples. Through a detailed and systematic investigation, we suggest a simple, fast, and cost-effective method for preparing transverse surfaces of wood for scanning electron microscopy. The methodology used is easily accessible and simple. We compare traditional microtome cutting using both disposable blades and a fixed knife with sanding and polishing techniques. The choice of method is determined by the physical condition and structural characteristics of the sample. Disposable blades, when used with continuous moistening, yielded the best results for reference wood, while the fixed knife proved to be more effective for mineralized or epoxy-embedded samples due to their rigidity and resistance to deflection. Maintaining blade sharpness and surface moisture were critical in all cutting techniques. Polishing proved to be a particularly effective technique for the preparation of degraded, mineral-rich, or heterogeneous samples. In combination with epoxy embedding, it offers a practical alternative to microtome cutting, ensuring the protection of fragile structures, the long-term stability of samples, and the possibility of re-polishing. Epoxy impregnation was easy for degraded wood, while sprucewood required vacuum-pressure treatment. Care must be taken when polishing to avoid reaching non-embedded regions beneath the surface.
Keywords: epoxy resin impregnation, polishing and sanding, sample preparation, scanning electron microscopy, wood
Published in DiRROS: 27.01.2026; Views: 93; Downloads: 56
 Full text (3,32 MB)
This document has many files! More... |
2. Non-invasive techniques in consolidation study of dolomitic lime plasters : application to wall paintingsZala Žarkovič, Andreja Pondelak, Ajda Mladenovič, Sabina Dolenec, 2025, published scientific conference contribution Abstract: The consolidation of lime-based plaster materials plays a vital role in preservation of built heritage. Wall paintings are particularly vulnerable due to the fragile nature of lime-based substrates and their susceptibility to deterioration. While calcium lime plasters are frequently studied, there seem to be few studies on the consolidation of wall paintings produced with dolomitic lime. This research evaluates the effectiveness of three carbonate-based consolidants — calcium acetoacetate (CFW), Nanorestore (NR), and NanoLaq (NL) applied individually and in combinations, to assess their mechanical and aesthetic effects on dolomitic lime models. Non-invasive methods included microhardness testing, ultrasonic velocity measurements and micro-invasive method as the drilling resistance measurement system (DRMS) to measure penetration depth and change in mechanical properties. Spectrophotometry was used to monitor colour changes after the application of consolidants. This research emphasizes the significance of using advanced diagnostic tools for evaluating and improving conservation treatments for wall paintings. Results showed that combined applications of CFW with nanolimes improved cohesion and depth performance significantly more than individual treatments. The findings contribute to sustainable practices in heritage preservation and align with ongoing efforts to refine consolidant formulations for better performance.
Keywords: non-destructive testing, infrared thermography, historic concrete preservation, ground penetrating radar (GPR), ultrasound tomography
Published in DiRROS: 15.01.2026; Views: 209; Downloads: 93
Full text (387,44 KB)
This document has many files! More... |
3. Dynamic mechanical analysis of fpu bonded beech wood at various temperaturesMartin Capuder, Boris Azinović, Andreja Pondelak, Paweł Rutkowski, Magdalena Szumera, Matthew Schwarzkopf, Arkadiusz Kwiecień, Klaudia Śliwa-Wieczorek, Jaka Gašper Pečnik, 2025, published scientific conference contribution Abstract: This study investigates the dynamic mechanical properties of flexible polyurethane (FPU) adhesives bonded to European beech wood (Fagus sylvatica L.) using Dynamic Mechanical Analysis (DMA) over a range of temperatures and frequencies. Samples included clear beech wood and three-layered composite (beech:FPU:beech). DMA tests were performed using a three-point bending setup at 1 Hz and 10 Hz in the temperature range from -120°C to 140°C. The results demonstrated high thermal stability and strong bonding performance of FPU adhesives on beech wood. Frequency-dependent responses varied among FPU types but resembled the behavior of solid wood at lower temperatures. This confirms the suitability of DMA for evaluating adhesive-wood composite behavior under dynamic conditions. The combination of FPU adhesives and beech wood showed potential for thermally stable and energy-dissipating bonded assemblies.
Keywords: dynamic mechanical analysis, FPU, beech wood
Published in DiRROS: 27.08.2025; Views: 456; Downloads: 216
Full text (2,05 MB)
This document has many files! More... |
4. Natural exposure comparison of timber joints bonded with polyurethane adhesive in two climatic conditionsMartin Capuder, Gary M. Raftery, Weixi Wang, Zubin Karami, Boris Azinović, Andreja Pondelak, Luka Naumovski, Tomaž Pazlar, 2025, published scientific conference contribution Abstract: The increased use of engineered wood in the built environment is attracting much attention because of the significant sustainable attributes. The formation of high quality reliable structural adhesive bonds is essential during the manufacture of such products. This research examines and compares the performance of bonded European beech and Radiata pine subject to natural weathering, comparing untreated, preservative treated and mineralized wood. Bonded joints were naturally weathered in Slovenia and New Zealand, respectively. The fracture energy was evaluated through Mode I fracture tests using the double cantilever beam arrangement at various ageing stages. FTIR analysis was conducted to assess chemical changes in the adhesives and wood substrate. The research provides insights into the interactions between ageing, wood species, and adhesive performance, enhancing timber structures sustainability.
Keywords: durability, weathering, climate, adhesive bond, mode I fracture testing
Published in DiRROS: 27.08.2025; Views: 483; Downloads: 203
Full text (2,43 MB)
This document has many files! More... |
5. Mehanske lastnosti lepljenih spojev : vpliv izpostavljenosti in naravnega staranjaMartin Capuder, Boris Azinović, Andreja Pondelak, Tomaž Pazlar, Jaka Gašper Pečnik, Luka Naumovski, 2025, published scientific conference contribution abstract Keywords: bukev, lepljen spoj, FTIR, naravna izpostavitev, mehanske lastnosti lesa
Published in DiRROS: 05.06.2025; Views: 650; Downloads: 245
Full text (40,71 KB) |
6. |
7. Stabilization of fish protein‐based adhesive by reduction of its hygroscopicityBranka Mušič, Jaka Gašper Pečnik, Andreja Pondelak, 2024, original scientific article Abstract: Protein-based fish adhesives have historically been used in various bonding applications; however, due to the protein’s high affinity for water absorption, these adhesives become destabilized in high-moisture environments, resulting in reduced bondline strength and early failure. This limitation makes them unsuitable for industrial applications with higher demands. To address this issue, water-insoluble raw powder materials such as iron, copper, or zeolite were incorporated into natural fish adhesives. In this study, the hygroscopicity, dry matter content, thermal analysis (TGA/DSC), FT-IR spectroscopy, surface tension measurements, vapour permeability, and scanning electron microscope (SEM) of the modified adhesives were determined. In addition, the bonding properties of the modified adhesives were evaluated by the tensile shear strength of the lap joints, and mould growth was visually inspected. The resulting modified protein-based adhesives demonstrated improved stability in high humidity environments. Enhancing the hygroscopic properties of protein-based fish adhesives has the potential to unlock new opportunities and applications, providing a healthier and more environmentally sustainable alternative to petroleum-based adhesives.
Keywords: protein‐based adhesive, polymer stabilization, hygroscopicity, fish adhesive modification, fish industry waste, circular economy, bonding properties
Published in DiRROS: 12.08.2024; Views: 1202; Downloads: 841
Full text (15,12 MB)
This document has many files! More... |
8. Lastnosti lesa iz rudnika SitarjevecMiha Humar, Boštjan Lesar, Davor Kržišnik, Andreja Pondelak, Andrijana Sever Škapin, Angela Balzano, José Gonçalves, 2024, original scientific article Abstract: Rudarska tradicija v Litiji, segajoča v staro železno dobo, je vključevala intenzivno uporabo lesa v rudnikih, še posebej za podporo in zaščito rovov. Rudnik Sitarjevec je bil znova odprt za turizem leta 2017, in v letu 2021 so odprli glavni rov. Les ostaja ključen material v rudnikih, čeprav so ga v preteklosti nadomeščali z drugimi materiali. Uporabljeni les je izpostavljen razkroju zaradi visoke vlažnosti in gliv, kot je bela hišna goba. Ta gliva lahko povzroči razgradnjo lesa in je pogosta v vlažnih okoljih rudnikov. Obstoj gliv je pomemben, saj lahko vplivajo na obiskovalce rudnika. Visoka relativna zračna vlažnost (96,6 %) in stalna temperatura (10,1 °C) v rudniku ustvarjata razmere, ki so ugodne za rast gliv, vendar pa relativno nizka temperatura ni omejujoč dejavnik za razgradnjo lesa. Koncentracija glivnih spor v rudniku je visoka in je razložena z razširjenostjo gliv v samem rudniku. Poleg tega smo opazili, da je v lesu veliko anorganskih onesnaževal ter veliko kristalov.
Keywords: razkroj, bela hišna goba, težke kovine, kristali, spore
Published in DiRROS: 22.07.2024; Views: 968; Downloads: 422
Full text (4,45 MB) |
9. Lastnosti lesa iz rudnika SitarjevecMiha Humar, Boštjan Lesar, Davor Kržišnik, Andreja Pondelak, Andrijana Sever Škapin, Angela Balzano, José Gonçalves, 2024, original scientific article Abstract: Rudarska tradicija v Litiji, segajoča v staro železno dobo, je vključevala intenzivno uporabo lesa v rudnikih, še posebej za podporo in zaščito rovov. Rudnik Sitarjevec je bil znova odprt za turizem leta 2017, in v letu 2021 so odprli glavni rov. Les ostaja ključen material v rudnikih, čeprav so ga v preteklosti nadomeščali z drugimi materiali. Uporabljeni les je izpostavljen razkroju zaradi visoke vlažnosti in gliv, kot je bela hišna goba. Ta gliva lahko povzroči razgradnjo lesa in je pogosta v vlažnih okoljih rudnikov. Obstoj gliv je pomemben, saj lahko vplivajo na obiskovalce rudnika. Visoka relativna zračna vlažnost (96,6 %) in stalna temperatura (10,1 °C) v rudniku ustvarjata razmere, ki so ugodne za rast gliv, vendar pa relativno nizka temperatura ni omejujoč dejavnik za razgradnjo lesa. Koncentracija glivnih spor v rudniku je visoka in je razložena z razširjenostjo gliv v samem rudniku. Poleg tega smo opazili, da je v lesu veliko anorganskih onesnaževal ter veliko kristalov.
Keywords: razkroj, bela hišna goba, težke kovine, kristali, spore
Published in DiRROS: 21.06.2024; Views: 1806; Downloads: 554
Full text (4,45 MB) |
10. |
