Fabrication of Tm2O3/Al2O3-silica preform by improved MCVD-chelate delivery system

The fabrication of Tm/Al-doped silica preforms by an improved MCVD method with metal chelate precursors is discussed. Two fabrication techniques are employed, namely; simultaneous soot-dopant deposition (or standard MCVD) and stepwise soot-dopant deposition. The preforms are characterized by refractive index profiler and EPMA. The results show that the stepwise soot-dopant technique has a higher incorporation of Al2O3 and Tm2O3 as compared to the simultaneous soot-dopant method. This is due to the drawbacks of our chelate delivery system such as the temperature gradient and flow design. For the stepwise technique, the measured index difference of the preform is 0.006 with 0.8 wt% (maximum) Tm incorporated in the core

Treatment of Oil Palm Wood with Low-Molecular Weight Phenol Formaldehyde Resin and Its Planing Characteristics

In line with the Malaysian government calls to turn waste into wealth, oil palm wood (OPW) is establishing itself as a potential wood substitute. However, the OPW on its own has four imperfections, i.e.: low strength, low durability, poor dimensional stability, and poor machining characteristics. Previous studies have shown that the first three imperfections were able to be solved by impregnating with low molecular weight phenol formaldehyde (Lmw-PF) through modified compreg method. But, the machining behaviour of OPW remains uncovered. A planing test was carried out to evaluate the machining characteristics of the treated OPW. For comparison purpose, another set of test for the rubberwood and untreated OPW samples were also conducted. It is acknowledged that the planing quality of the treated OPW is of equal grade to that of rubberwood. In general, the planing of the treated OPW and the rubberwood fell into the Grade I (very good), compared to Grade III (average) for untreated OPW. The treatment significantly improves the machining characteristics of OPW, adding significant improvements on the physico-mechanical properties, durability, and appearance that have been proven in the previous studies, which make it can be used as a new, high-grade alternative for solid wood material

Mechanical and physical properties of oil palm trunk core particleboard bonded with different UF resins

Rapid price increases and reduc­tion in the sup­ply of rub­ber­wood has forced the par­ti­cle­board man­u­fac­tur­ers to look for new alter­na­tive raw mate­ri­als. The pro­duc­tion of par­ti­cle­board from other wood species will be a good solu­tion to the prob­lem of deplet­ing wood sup­plies. The objec­tive of this study was to eval­u­ate the prop­er­ties of par­ti­cle­board made from rub­ber­wood and oil palm trunk pressed at dif­fer­ent tem­per­a­tures and times com­pared to par­ti­cle­boards made from sin­gle species. Two types of UF resins (E1 resin and SE0 resin) were applied in this study. The effect of surface-to-core ratio was also exam­ined in this study. The mod­u­lus of rup­ture, inter­nal bond strength and thick­ness swelling of the boards were eval­u­ated based on the Japan­ese Indus­trial Stan­dard for par­ti­cle­board (JIS A 5908:2003). After eval­u­a­tion, the pan­els pro­duced are a poten­tial sub­sti­tute to the pan­els made from pure rubberwood