Transesterification of Palm-based Methyl Palmitate into Esteramine Catalyzed by Calcium Oxide Catalyst

The technology for transesterification reactions between methyl esters and alcohols is well established by using classical homogeneous alkaline catalysts, which provide high conversion of methyl esters to specialty or nonindigenous esters. However, in certain products where the purity of the esters is of concern, the removal of homogeneous catalysts after the completion of the reaction is a challenge in terms of production cost and water footprint. Therefore, a study to investigate the potential of heterogeneous catalysts was conducted on reactions between methyl palmitate and triethanolamine. The degree of basicity and active surface area of calcium oxide (CaO), zinc oxide (ZnO), and magnesium oxide (MgO) were first characterized by using temperature-programmed desorption (TPD-CO₂) and Brunauere–Emmett–Teller (BET), respectively. Among the metal oxides investigated, the CaO catalyst showed the best catalytic activity toward the transesterification process as it gave the highest conversion of methyl palmitate and yielded fatty esteramine compositions similar to the conventional homogeneous catalyst. The optimum transesterification condition by using the CaO catalyst utilized a lower vacuum system of approximately 200 mbar, which could minimize a considerable amount of energy consumption. Furthermore, low CaO dosage of 0.1% was able to give a conversion of 94.5% methyl ester and formed esteramine at 170 °C for 2 h. Therefore, the production of esterquats from esteramine may become more economically feasible through the methyl ester route by using the CaO catalyst, which can be recycled three times.     

Thermomechanical behaviour of composites

This paper derives the governing equations for the thermomechanical behaviour of composites. When the basic equations for the thermoelastic behaviour of solids were first derived in the nineteenth century several approximations were made. The effect of these assumptions are discussed and illustrated by the results of a simple laboratory test. The implications of this work on the analysis of impact damaged laminates are then discussed.     

Development of Stretch Solder Interconnections for Wafer Level Packaging

A wafer level packaging technique has been developed with an inherent advantage of good solder joint co-planarity suitable for wafer level testing. A suitable weak metallization scheme has also been established for the detachment process. During the fabrication process, the compliancy of the solder joint is enhanced through stretching to achieve a small shape factor. Thermal cycling reliability of these hourglass-shaped, stretch solder interconnections has been found to be considerably better than that of the conventional spherical-shaped solder bumps.     

Ice-slurry production using direct contact heat transfer

An ice slurry generation system was developed using direct contact heat transfer between water and the coolant, Fluroinert FC-84. The location of the coolant nozzle is an important design consideration to avoid clogging due to freezing of water. An ice fraction of up to about 40 percent was obtained with the nozzle located at the bottom of the ice slurry tank and the jet directed upwards into the water. Two simplified model were developed to extract the heat transfer coefficient between the coolant drops and the water. The first model requires as input the average drop diameter and the residence time while the second model uses the measured drop diameter distribution. The estimated heat transfer coefficients are much smaller than those computed using single-sphere correlations.     

Analysis of composite laminates with transverse cracks

The analysis of the behaviour of composite laminates with general balanced lay-up sequences and containing distributed transverse cracks is discussed and demonstrated in this paper. It is shown that a constitutive model of damage for composites, which has been successfully used to analyse the effects of uniformly distributed transverse cracks in cross-ply laminates, can be readily extended to the analysis of uniformly distributed transverse cracks in more general symmetric laminates. The further extension of the theory to non-uniformly distributed damage can be achieved by finite element analysis. It is shown that the finite element implementation of the theory is particularly simple since the contribution of the damage to the overall behaviour can be incorporated into the force vectors.