Development of coating materials from liquid wax esters for wood top-based coating

Of late, UV-curable products are gaining attention in the wood industry because of the effectiveness and efficiency of this method. UV-curable surface coatings are widely used because of their excellent properties and because they are environmentally friendly products. In this study, immobilized Candida antarctica lipase B was used to catalyze formation of liquid wax esters, such as adipate esters, via a solvent-free process. The adipate esters formed were then used as UV-curable reactants in the wood coating formulations, consisting of epoxy acrylate, additives, and a photoinitiator. The performance of the products was evaluated by coating them onto glass tiles (using gel content, hardness, and scratch resistance tests) and wood panels (using adhesion, impact, and heat resistance tests). The coated film from this formulation performed well during the evaluation tests. The gel content exhibited more than 90% polymerization, while the pendulum hardness gave a value of 55.25%. Both analyses were significant in determining the effect of irradiation cycles. A scratch test was also carried out to verify the resistance of the coating. The maximum weight load which can be resisted by the wax esters formulation is 4.5 N.     

Convergence of a general iterative scheme for a finite family of asymptotically quasi-nonexpansive mappings in convex metric spaces and applications

In this paper, we introduce the iterative scheme due to Khan, Domlo and Fukhar-ud-din (2008) [8] in convex metric spaces and establish strong convergence of this scheme to a unique common fixed point of a finite family of asymptotically quasi-nonexpansive mappings. As a consequence of our result, we obtain some related convergence theorems. Our results generalize some recent results obtained in [8].     

A fault-tolerant communications switch prototype

A fault-tolerant communications switch prototype supporting the packet switching communications paradigm has been implemented. The special feature of this switch is that it incorporates a modified version of the grouped adaptive function, found in the Inmos IMS C104 switch, which can logically group both consecutively and non-consecutively numbered links.     

Composites as cracking catalysts in the production of biofuel from palm oil: Deactivation studies

Composite catalysts HZSM-5/alumina (CZA) and Al-MCM-41/alumina (CMA) were synthesized and tested for their catalytic cracking activity in the production of biofuel from palm oil. Both composite catalysts were characterized for their structure, acidity and surface morphology. The addition of alumina in the composite catalysts improved their hydrothermal stability due to the changes in the surface morphology. The deactivation of the catalysts was studied by obtaining time on stream data by varying the palm oil to catalyst ratio of 8–16. The deactivation data were analyzed using different activity models and the deactivation parameters were determined.     

Pseudohalogenation of methyl 9-hydroxy-cis-12-and 12-hydroxy-cis-9-octadecenoate

Pseudohalogenation of methyl 9-hydroxy-cis-12-octadecenoate (I) and methyl 12-hydroxy-cis-9-octadecenoate (II) has been carried out with N,N-dibromobenzenesulfonamide (NNDBS). Compounds I and II, on reaction with NNDBS, formed four and three products, respectively. The interesting feature of these reactions was the formation of 1,4-epoxy compounds. The structures of individual compounds were established with the help of elemental and spectral analysis.     

Investigation of a windvent passive ventilation device against current fresh air supply recommendations

Recent ecological and political developments have created an increased focus on sustainable energy sources. The purpose of this paper is to examine a passive ventilation device, the windvent, and evaluate its potential against current British Standards BS5952:1991 [British Standards, Ventilation principles and designing for natural ventilation, BS5925:1991 (1991)] recommended fresh air delivery rates. The results provide useful information for both engineers and architects when examining ways to reduce new and existing buildings running costs, and conform to new legislation. Numerical analysis is carried out using a commercial Computational Fluid Dynamics (CFD) code, to investigate the effect of various external wind velocities (1–5 m/s) and directions (concurrent and counter current) on the device performance. The results show that the windvent is capable of providing recommended rates of fresh air supply even at relatively low incident wind velocities. The performance indications show that the device warrants further analysis and provides a sustainable alternative ventilation system.     

The effect of heat treatments on the properties of Ti/Pt heating elements for gas sensor applications

Ti/Pt as heating element for gas sensor applications was fabricated on silicon (Si) wafer substrate. The fabricated device was subjected to heat treatment at different prescribed time periods for thermal stability. The energy dispersion spectroscopy (EDS) results of the device indicated that there were no Ti traces on the Pt surface after heat treatment at 450 °C for 3 and 4 h in an argon (Ar) atmosphere. A maximum temperature coefficient of resistance (TCR) with a value of 2.88×10^?3 K^?1 was obtained for the device with 3 h heat treatment.