A neural network model for the wire bonding process

A crucial step in manufacturing microcircuits is the wire bonding process in which a very thin gold wire must be formed to connect two surfaces in the microcircuit. The quality of the wire bond can be measured by visual inspection and a pull test—both of which are high-reliability, high-cost approaches to statistical process control. Westinghouse wanted to develop a high-reliability, low-cost quality assurance system. In this paper, we report on a year-long study to construct a neural network model that is capable of predicting the quality of wire bonds. The results of our modeling efforts reveal that neural networks are useful tools for statistical process control problems.     

Do changes in cognitive factors influence outcome following multidisciplinary treatment for chronic pain? A cross-lagged panel analysis.

Changes in maladaptive cognitions may constitute therapeutic processes of multidisciplinary pain programs. A cross-lagged panel design was used to determine whether (a) early-treatment cognitive change predicted late-treatment outcome index change, but not vice versa; and (b) these effects remained significant with depression change controlled. Ninety chronic pain patients, in a 4-week multidisciplinary program, completed measures of catastrophizing, pain helplessness, depression, pain, interference, and activity level at pre-, mid-, and posttreatment. With depression changes controlled, early-treatment catastrophizing and pain helplessness changes predicted late-treatment outcome index changes, but not vice versa; early-treatment depression changes predicted late-treatment activity changes, but not vice versa. Findings advance understanding of pain treatment process and suggest that negative cognition changes may indeed affect improvements in treatment outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Public–Private Partnerships in the Water Sector: The Case of Desalination

Water Resources Management - Public–private partnerships (PPPs) have grown in popularity as a method to leverage private sector actors in the production of government services. With the...     

Inside this month

This issue contains a preview of the CFA’s annual trade show, which this year takes place in Anaheim, California. Those of you who also attend the JEC Composites Show in Paris will see a vast difference between these two events, not only in cultural terms but also in focus. CFA is an association for US manufacturers and its show places a high emphasis on education and networking. JEC’s slant is to the end-user and it strives to be a showcase for composites technology. Both of these approaches are to the ultimate benefit of the composites industry, but as companies continue to look at ways of spending their money more effectively, show attendance is one area coming under increasing scrutiny. Many have been saying that it is too expensive to attend JEC every year and now a group of major resin suppliers, including DSM, Reichhold, Ashland and Cray Valley, have taken the step of staying away from next year’s show (see page 64). This will surely dent the show’s profits and it will be interesting to see how the organisers, as well as other exhibitors, will respond to this development.     

Mutation of herpesvirus thymidine kinase to generate ganciclovir-specific kinases for use in cancer gene therapies

Understanding the functional and mechanistic properties of themulti-substrate herpes simplex virus type-1 thymidine kinase(HSV-1 TK) remains critical to defining its role as a majorpharmacological target in herpesvirus and gene therapies forcancer. An inherent limitation of the activity of HSV-TK isthe >70-fold difference in the K_ms for phosphorylation ofthymidine over the pro-drug ganciclovir (GCV). To engineer anHSV-1 TK isoform that is specific for GCV as the preferred substrate,16 site-specific mutants were generated. The mutations wereconcentrated at conserved residues involved in nucleoside basebinding, Gln125 and near sites 3 and 4 involved in catalysisand substrate binding. The substrate preferences of each mutantenzyme were compared with wild-type HSV-1 TK. One mutant, termedQ7530 TK, had a lower K_m for GCV than thymidine. Expressionof the Q7530 TK in tumor cells indicated comparable metabolismto and improved sensitivity to GCV over wild-type HSV-1 TK,with minimal thymidine phosphorylation activity. A molecularmodeling simulation of the different HSV-1 TK active-sites wasdone for GCV and thymidine binding. It was concluded that mutationsat Gln125 and near site 4, especially at Ala168, were responsiblefor loss of deoxypyrimidine substrate binding.     

Effect of DAG on milk fat TAG crystallization

The effect of milk fat and standard DAG on the crystallization behavior of milk fat TAG (MF-TAG) was investigated. When milk fat DAG were added to MF-TAG at the 0.1 wt% level, crystallization was delayed. Racemic purity was shown to be an important factor in the ability of DAG to influence TAG crystallization. Only sn-1,2 isomers of blends of MF-TAG with 0.1 wt% of the racemic mixtures of dipalmitin and diolein increased the activation free energy barrier to MF-TAG nucleation (ΔG _c ) and delayed the subsequent crystallization process by increasing the crystallization induction time (τ_SFC) determined from solid fat content-time measurements. Although crystallization kinetics were affected, the properties of the resulting network structures remained unchanged upon addition of milk fat minor components at the 0.1 wt% level     

Synthesis of Biodiesel from Canola Oil Using Heterogeneous Base Catalyst

A series of alkali metal (Li, Na, K) promoted alkali earth oxides (CaO, BaO, MgO), as well as K₂CO₃ supported on alumina (Al₂O₃), were prepared and used as catalysts for transesterification of canola oil with methanol. Four catalysts such as K₂CO₃/Al₂O₃ and alkali metal (Li, Na, K) promoted BaO were effective for transesterification with >85 wt% of methyl esters. ICP-MS analysis revealed that leaching of barium in ester phase was too high (~1,000 ppm) when BaO based catalysts were used. As barium is highly toxic, these catalysts were not used further for transesterification of canola oil. Optimization of reaction conditions such as molar ratio of alcohol to oil (6:1–12:1), reaction temperature (40–60 °C) and catalyst loading (1–3 wt%) was performed for most efficient and environmentally friendly K₂CO₃/Al₂O₃ catalyst to maximize ester yield using response surface methodology (RSM). The RSM suggested that a molar ratio of alcohol to oil 11.48:1, a reaction temperature of 60 °C, and catalyst loading 3.16 wt% were optimum for the production of ester from canola oil. The predicted value of ester yield was 96.3 wt% in 2 h, which was in agreement with the experimental results within 1.28%.