Cassava is a type of crop popular in Asian countries. It can be easily cultivated and grows to a mature plant in 9 months. Considering its availability, this work studied activated carbon based on cassava stem. Ofloxacin was chosen as the adsorbate, simulating the wastewater from the pharmaceutical industry. Cassava stem was ground into particles and heated to the activated state, 787 °C. The cassava-stem-activated carbon was further treated with the surface modifier, namely sodium hydroxide and zinc chloride, to study the improvement in ofloxacin adsorption. Prepared adsorbents were characterised using the SEM, FT-IR, XRD, DSC and TGA methods before being evaluated through batch adsorption, thermodynamic, and kinetic studies. The surface area analysis indicates that treatment of the activated carbon with NaOH and ZnCl₂ increases the surface area due to the removal of organic content by the chemicals. Better ofloxacin adsorption of all activated carbon samples can be obtained with solutions at pH 8. An endothermic reaction was predicted, shown by higher ofloxacin adsorption at a higher temperature, supported by a positive value of ΔH° in the thermodynamic studies. The negative values of ΔG° revealed that adsorptions were spontaneous. The higher R² values indicate that the adsorption process follows the pseudo-second-order equation of kinetic study. The maximum adsorption capacities are 42.37, 62.11, 62.89 and 58.82 mg/g for raw cassava stem (RC), cassava-stem-activated carbon (AC), NaOH-modified cassava-stem-activated carbon (NAC), and ZnCl₂ modified cassava-stem-activated carbon (ZAC). The adsorption capacity is good compared to previous works by other researchers, making it a possible alternative material for the pharmaceutical industry’s wastewater treatment.

This study investigated how the mechanical properties of L-shape joints produced from heat treated Scotch pine or ash wood behaved under cyclic fatigue loading and compared this with the mechanical properties of non-heat treated wood materials. Additionally, static bending performances of the L-shape of joints were investigated and compared to fatigue bending performance of same type of joints. Results indicated that increasing number of staple from 6 to 8 and density generally increased static bending of L-shape joints. Static bending resistance of L-shape joints produced from control Ash wood significantly higher than those of L-shape joints produced from heat treated Ash wood while no significant difference were observed between static bending resistance L-shape joints produced from control Scotch pine and L-shape joints produced from heat treated Scotch pine wood. The fatigue bending resistances of L-shape joints produced from heat treated samples generally passed and failed the same loading steps with those produced from control samples which means both L-shape joints could be used in same service area. L-shape joints under static and fatigue loadings mostly indicated staple leg shear mode. The one under fatigue loading was more than the one under static loading. Additionally, some joints under fatigue loading indicated staple rupture. The overall ratio of static bending loading to cyclic fatigue bending loading for L-shape joints was obtained as 2.85.

The additive effects of the number of staples and gluing on ultimate lateral resistance loads of surface-to-surface, multistaple- and glue-connected joints in oriented strandboards (OSB) were investigated. Experimental results indicated that for a stapled–glued OSB joint with a given configuration of surface-tosurface bonding area of two joint members, its ultimate lateral resistance load and stiffness are governed by the number of staples used and gluing, respectively. Applying glue to multistaple-connected OSB joints can alter the effect of the number of staples used on their ultimate lateral resistance loads. Gluing increases joint lateral resistance loads, but this increase will not be significant when the number of staples used reaches a critical number. Applying glue to a stapled OSB joint improves its stiffness when compared with the stiffness of a stapled-only joint. The differences in ultimate lateral resistance loads of stapled–glued joints among three OSB materials evaluated in this study were not significant when the number of staples was six or less, and the differences became significant when the number of staples increased to eight.

The shear strengths of the joints produced by using Poly Lactic Acid (PLA), PLA+ Thermoplastic Polyurethane (TPU), and resin (Acrylic Photopolymer) with three different surface design of the dowels including, grooved, straight, and cross were investigated compared, wood and plastic dowels. The Results indicated that among L-type furniture joints, those manufactured from PLA and conventional wood dowels displayed the highest shear resistance, followed by L-type furniture joints with dowels made from PLA+TPU, resin, and plastic. Generally, differences in dowel patterns did not have a statistically significant impact on the shear resistance of L-type joints, except for the straight pattern dowels made of resin, which exhibited a statistically higher shear resistance than the grooved pattern dowels. Regarding the failure mode results, only PLA, PLA+TPU, and wooden dowels showed signs of elongation and crushing within the dowel holes. Conversely, in joints using dowels produced from resin and plastic, the dowels broke under shear stress, without displaying elongation, and did not leave any evidence of crushing in the dowel holes. Overall, the results of the study indicated that dowels made only PLA exhibited similar shear resistance compared to conventional wood dowels. Additionally, the study demonstrated that 3D-printed dowels were stronger than conventional plastic dowels.

Since staple is the most used fastener in furniture frame, its holding capacity in solid wood joints is need to be known. Therefore, lateral shear resistance capacity of one stapled and one-row multi stapled joints constnicted from Scotch pine, alder, and beech Were investigated. Results showed that the joints constructed from beech with a density of 540 kg/m(3) yielded 4893 N, the 4 staples joints constructed from alder with a density of 510 kg/m(3) yielded 4487 N. and the 4 staples joints constructed from Scotch pine with a density of 450 kg/m3 yielded 3498 N. Three and to staples connected joints also indicated decreasing trend when changing wood from beech to alder and Scotch pine. Results also indicated that increasing number of staple from 2 to 4 in one row joints increased force of the joints. Two prediction equations were derived to predict the shear of one-row multi stapled wood joints. Both equations yielded remarkable results compared to actual laboratory test results.

In this study, creep characteristics of single stapled furniture joints made of Scotch pine, alder and beech wood under three different load levels were considered. Load levels were determined as 30 %, 40 % and 50 % of the maximum load obtained as a result of static shear test before creep load and applied to wood joints. Laboratory test results showed that the highest creep deformation was observed in the joints made of Scotch pine with the lowest density, while the lowest creep deformation was observed in the joints made of beech with the highest density. In addition, the joints were exposed to lowest creep deformation at the 30 % load level, then the creep deformation of the joints increased at 40 % load level and it reached the highest value at 50 % load level. As a result of creep test, deformation in single stapled joints made of Scotch pine, alder and beech were determined as 2.74 %, 3.71 % and 4.37 % of the deformation that occurred as a result of static shear test performed before creep test, respectively. Ultimately, the overall average creep deformation value of a single staple wood joint under creep loading was determined as 3.61 %.