Research Articles

The hasapi of the Batak Toba from Sumatra, Indonesia is a plucked bowl-lute chordophone. Hasapi is a fretless chordophone with two strings. The tuning for the hasapi used in this study is based on the transcription of the song ‘Horbo Paung’ played in F major by Sam Sitio. The tuning used for the 2^nd string is C4 (Do for open string) followed by D4, E4, and F4 for 1^st, 2^nd, and 3^rd finger, respectively. The 1^st string was tuned to G4 (So for open string), followed by A4, B4, and C5 for 1^st, 2^nd, and 3^rd finger, respectively. At higher notes (1^st string) the spectra did not display many harmonics, i.e., less partials compared to the lower note (2^nd string). Both strings showed a regular signal, whereas the highest note C5 (the highest fundamental frequency from the 1^st string) showed an irregular pattern with no significant overtone frequency. The intensity of the partials in both strings displayed the reduction in amplitudes i.e. not proportional to increasing harmonic frequency. The timbre from Adobe Audition showed that the time frequency analysis (TFA) was in accordance with the Picoscope spectra. Only TFA from C5 showed irregular pattern with respect to the Picoscope output.

Even though making thin sheets of cellulose nanofiber by a papermaking-like process is straightforward, obtaining thicker papers or plates is extremely time consuming. Dewatering is exceedingly slow as the nanocellulose is deposited on the filter paper during filtration, hindering water flow. This study proposes a simple device that speeds up dewatering through the application of air pressure on the aqueous suspension being filtered. A relative pressure of 0.5 MPa reduced the dewatering time of 72 h for a conventional vacuum filtration to 16 h without compromising the mechanical properties of the final molded material.

Rice production in Asia is a cornerstone of global food security. Implementing innovative crop establishment practices and utilizing nano fertilizers can enhance rice yields and mitigate environmental concerns, thereby contributing to a resilient and sustainable food system. Therefore, a field experiment was conducted over 2020 and 2021 that included various methods of application (seed treatment, root dipping, soil and foliar application) of nano fertilizers (nano nitrogen and nano zinc) under different rice establishment methods (conventional paddy and SRI). Statistical analysis was performed using Fisher’s analysis of variance and Duncan’s multiple range test (p ≤ 0.05). The findings showed that the application of 75% N and two foliar sprays of nano-nitrogen and nano-zinc at 25 to 30 and 45 to 50 days after transplanting under System of Rice Intensification method (Treatment T₁₄) was statistically superior in improving growth and yield parameters, grain and straw yield, and in enhancing the quality of rice over other treatments. Studies revealed strong positive correlations between all the measures, with the exception of the proportion of chaffiness and unfilled grains. The results of the stepwise regression analysis revealed the percentage dependence of grain and straw yield on growth, yield, and quality factors.

An increase in wood free surface energy enhances the wettability of wood surfaces, leading to better interaction with water-based coatings. This study investigated the effect of gas-phase ozonation on the wettability of spruce, thermo-modified pine, and birch woods. The effects of the treatment were evaluated by measuring the water contact angle and the Cobb value on the wood sample surfaces, and by determining the surface free energy of the wood surfaces using the Owens, Wendt, Rabel, and Kaelble (OWRK) calculation method. Furthermore, water absorption and evaporation rates were assessed through water immersion and subsequent drying of the wood samples. The results indicated that ozone treatment increased the surface energy, and especially its polar component, thus accelerating water spreading and absorption on the wood surfaces. The most probable cause of the observed effects is the formation of new carbonyl and carboxyl groups resulting from reactions of the ozone with the wood surface. The findings suggest that the ozone treatment technique can enhance spreading, absorption, and adhesion of water-based adhesives and coatings to wood surfaces. This research may facilitate the development and use of new environmentally friendly water-based adhesives and coatings.  

The tensile strength of paper towels with the addition of polyamidoamine-epichlorohydrin (PAE) polymer was tested. The papers were formed from a pulp consisting of pine and eucalyptus fibres in a 50/50 ratio. PAE was added to the paper pulp in an amount of 3.5 mg/g. The samples were pressed on a conventional press and dried on a drying cylinder. During the drying of the samples, the process parameters were changed, i.e., temperature (100 to 200 °C) and drying time (2 to 15 s). The drying conditions of the papers with the addition of PAE had a significant impact on the wet strength of the paper. The highest ratio of wet tensile index of the papers to dry tensile index in both directions, (MD and CD), was obtained for papers dried at 150 °C for 15 s. The results showed that with the increase in the dose of thermal energy supplied to the paper with the addition of PAE, its wet tensile strength increased. This applies to both the extension of the drying time and the increase in the drying temperature. Dry tensile strength tests of papers with the addition of PAE polymer showed that drying conditions were not of significant importance in that case.

Furan derivatives are recognized for their diverse biological activities, particularly their antimicrobial properties. In this study, three new furan derivatives were isolated from acid-treated Chrysanthemum indicum flowers. The structures were elucidated using spectroscopic techniques and identified as methyl (E)-3-((5-(methoxymethyl)furan-2-yl)methylene)-4-oxopentanoate (1), methyl (Z)-3-((5-(methoxymethyl)furan-2-yl)methylene)-4-oxopentanoate (2), and  methyl (E)-3-(furan-2-ylmethylene)-4-oxopentanoate (3). These compounds were evaluated for antibacterial activity against Vibrio spp. and Microcystis aeruginosa. Compound 3 showed the highest inhibition (63.5%) against M. aeruginosa at 50 μg/mL, with compounds 1 and 2 demonstrating lower activities (36.1% and 58.3%, respectively). The structural difference between compounds 1 and 2, limited to the double bond geometry, likely contributes to their varying efficacies. These findings indicate that furan derivatives from C. indicum could be promising candidates for antimicrobial applications, particularly in aquaculture.

Polypropylene (PP) with black locust wood flour and maleic grafted polypropylene were used to prepare wood plastic composites (WPC) by injection molding. The effect of the addition of nano titanium oxide (nano TiO₂) on the properties of the composites was investigated. The specimens were weathered in an accelerated weathering apparatus using a xenon arc lamp for 2000 h. The physical properties of the composites were evaluated by colorimetry, water absorption, and thickness swelling before and after weathering. Mechanical properties of WPC were also determined before and after weathering. The WPC containing 0.75 phr nano TiO₂ showed an improvement in the flexural and tensile strength and flexural and tensile modulus while the WPCs containing 0.2 phr nano TiO₂ showed an improvement in the impact strength. The UV resistance of the WPCs also improved with the incorporation of nano TiO₂ powder into the composites. Both water absorption and thickness swelling were found to be reduced by the incorporation of nano TiO₂ into WPC.

Wild olive (Olea europaea L.) is a highly significant forest tree species, both in Türkiye and globally. Its oil and other extracts from the fruits and leaves are vital to various industries, including culinary, cosmetics, pharmaceuticals, and healthcare, making it a valuable non-timber forest product. However, its natural distribution is restricted to Mediterranean climates, emphasizing the need for conservation efforts to support its growth and expansion. Potential distribution modelling is one of the best studies to be done to protect a species and ensure its survival. In this study, the MaxEnt method, which relies exclusively on presence data, was used to generate a potential distribution map for wild olive. The environmental variables to be included in the modeling method were determined using the Analytic Hierarchy Process (AHP), one of the multi-criteria decision-making methods. From an initial set of 29 variables, AHP selected the top 11 for the final model. The resulting model demonstrated high accuracy, with an AUC value of 0.922, successfully identifying and mapping the potential distribution areas for wild olive across Türkiye.

The aim of the paper was to optimize the settings of the material properties of a computer model describing heat transfer in a wooden beam exposed to thermal loading from a porcelain radiation panel. The methodology was based on performing medium-scale fire tests as a basis for a creation of finite element model with 6 different setups of material characteristics based on the outputs of tests. When adjusting the settings, the T-history method was used to determine a beginning and end of a phase change of the water content in the wood, a thermal conductivity was adjusted based on a density and a moisture content, and enthalpy was used instead of a specific heat. The results of the simulations were compared with the real medium-scale fire tests, which showed the importance of adjusting the input data. Based on the T-history method, the setting with a thermal conductivity value of 0.35 W·m^-1·K^-1 at a temperature of 114.8 °C was shown to be the best, with a coefficient of determination 98.7%.The results of the simulations showed that there could be a correlation between the moisture content of the wood and the maximum value of the thermal conductivity of the wood in the phase change of water.

Fungal endophytes were isolated from the leaves and petioles of Liquidambar orientalis Mill., an endangered species in Türkiye. Plant material was collected from 10 sites in September 2023, yielding 499 fungal isolates, classified into 38 morphological groups. DNA extraction and polymerase chain reaction (PCR) amplification of ITS and Beta-tubulin regions were conducted on representative isolates. All fungi belonged to the Ascomycota phylum, comprising 11 genera and 26 species across 15 families, with one group unidentified. The most prevalent families were Diaporthaceae (34.9%), Pleosporaceae (23.4%), and Botryosphaeriaceae (22.2%), with Diaporthe eres (15.0%) and Phomopsis sp. (12.4%) being dominant species. Fungal diversity was assessed using Shannon, Simpson, and Chao1 indices, revealing tissue type as the strongest factor influencing species diversity, followed by media and spatial factors. The presence of pathogenic families, such as Botryosphaeriaceae, highlights potential threats to the species. This is the first study to report fungal endophytes in L. orientalis, as well as the first records in Türkiye for several species, including Alternaria destruens, Alternaria alstroemeriae, Stemphylium majusculum, Diaporthe cynaroidis, Pseudopithomyces rosae, Nothophoma variabilis, Cladosporium endophyticum, Cladosporium colombiae, Muyocopron sp., Sphaerulina rhododendricola, Constantinomyces macerans, and Aequabiliella effusa.