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2016 - 201912020 - 20231
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Subject: Forest Products × Author: KAU × Start date: 2010 × Type: Thesis ×
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    ThesisItemOpen Access
    Preservation of coconut wood using inorganic nanoparticles
    (Department of forest products and utilization , college of forestry,Vellanikkara, 2023-12-22) Sidhartha, T N; KAU; Vishnu, R
    Coconut is a vital crop of Kerala, potential substitute for conventional timber. However, it is susceptible to termites, red palm weevils, bark weevils, shot hole or bark borers, and other pathogens. Traditional wood preservatives like Chromated Copper Arsenate and Chromated Copper Borate pose environmental risks. To address these challenges, researchers are exploring the concept of nanotechnology as a potential solution for wood protection. Nanoparticle has high efficiency to maintain wood natural color, and controlled release of active ingredients at a low concentration, making them a priority for future wood protection applications. As there is limited research on coconut's durability, degradability, and biocide properties of nanoparticles study has been conducted to understand the same. The copper and zinc nanoparticle was prepared by chemical reduction and precipitation method respectively. Medium and high density coconut wood was impregnated with this nanoparticles at 1%, 2.5% and 5% concentration. Two method of impregnation was carried out i.e., coating with fixative and pressure without fixative. Later, these samples were undergone chemical retention test, leaching test, subterranean termite test, weatherability test and water absorption test according to various standards of ASTM and AWPA. Nested anova was carried out to know the significant difference among various factors and their levels. Chemical reduction and precipitation method of copper and zinc nanoparticle preparation yielded 65.06% and 70.15% respectively. The SEM image of copper and zinc nanoparticles confirmed to have irregular cuboidal and flake shape with average size of 173.66 nm and 105.44 nm respectively. The presence of copper and zinc in the nanoparticles was verified by EDX analysis. The presence of the corresponding nanoparticles' metal-hydroxyl and metal-oxide groups was verified by the FTIR spectrum. XRD analysis shows that most of the copper in copper nanoparticles is present as copper oxide and cuprous oxide whereas, zinc nanoparticles as zinc oxide. The chemical retention of both pressure and coating treatment had significantly varied among various density, and nanoparticle concentrations. Among density, medium density had shown higher retention than high density. Concentration of 5% zinc and 5% xxix copper treated to medium density had shown greater retention among various nanoparticle concentration. The chemical leaching test showed that high leaching of nanoparticles occurred during initial stage. Pressure treated coconut wood with nanoparticles statistically varied between various density, nanoparticle and its concentration. High density had shown low leaching compared to medium density. Among nanoparticle and its concentration, zinc has shown the least leachability when compared to control. Same trend was seen in coating method. The subterranean termite test (no-choice) shown significant variation for mass loss and visual appearance among various density, and nanoparticles. While there was no significant difference seen with respect to different nanoparticle concentrations. Among density class medium was susceptible to termite attacks. Copper treated sample shown significant resistant to termite damage when compared to zinc treated sample. Statistically significant variation among density, nanoparticle and its concentration was seen in a weatherability test. High density sample was least susceptible to mass loss and greying. Zinc and copper treated sample shown excellent resistant to mass loss and greying as compared to control. Water absorption test shows a remarkable variation among density, nanoparticle and its concentration in the coconut wood treated by pressure and coating. Medium density shown greater water absorption and volume swelling percentage. Among nanoparticles, control shown more water absorption and volume swelling percentage. Hence, nanoparticles in wood preservation offer improved durability and performance due to their small size and unique properties. They offer enhanced resistance to leaching, termites, and other environmental factors, leading increased lifespan for wood-based products. However, further research is needed to ensure the safe and responsible application of nanoparticle-based wood preservation technologies, while considering cost and scalability.
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    ThesisItemOpen Access
    Dendroclimatological investigations on teak (Tectona grandis L. F.) in Nilambur (North) forest division of Kerala
    (Department of wood science, College of forestry, Vellanikkara, 2016) Sreejith Babu; KAU; Anoop, E V
    A study was conducted on teak (Tectona grandis L. f.) grown in plantations at Nilambur (North) forest division with the objectives of analyzing tree-ring chronologies to find out their dendroclimatic potential and the tree growth-climate relationship and also to find out whether any significant relationship exists between climate and mean vessel area (MVA) of teak and its prospect for climatic reconstruction of the study area. In order to achieve the above objectives, cross sectional discs were collected from sites located in Edakkode, Kanakuthu and Conolly’s plot. The average ring width and MVA of each year obtained from the different radii were used to cross date and construct the chronology using the TSAP Win software. A cubic smoothing spline was used for standardization of the tree ring data using the software ARSTAN. Bootstrap correlation and response function analyses were carried out with moving intervals to find out tree growth-climate relationship using DENDROCLIM was performed. Statistical parameters such as Signal to Noise Ratio (SNR) and Expressed Population Signals (EPS) of all chronologies have desired levels and the sites had good dendroclimatic potential. Ring width and MVA chronologies of teak for the Nilambur region were developed. Rainfall in previous July, previous December and current October were correlated with ring width. Winter temperature (December-January) and southwest monsoon (June- September) were the seasonal climatic variables that mostly controlled ring width in the study sites. The monthly temperatures for January and previous June created major response in ring width. Mean vessel area responded to monthly rainfall for months previous June, previous September, previous November and current May. Seasonal climate which influenced vessel area were of southwest monsoon (June-September) temperature and rainfall and northeast monsoon (October-November) rainfall. Mean vessel area responded to monthly temperatures of previous August, current May and December. Using transfer functions climatic data for months and seasons with highest response and the period which is not available (1870-1900) from the instrumental record were reconstructed from tree ring data.