Diameter-Controlled Synthesis of Polyaniline Nanofibers

Summary  Various diameters of polyaniline (PANI) nanofibers were easily made by varying the sweep rate in the electrochemical polymerization of the aniline monomer. At a sweep rate of 5 mV/s, the PANI nanofibers have an average diameter of 450 nm with a median of 440 nm. The fibers are short, on the order of a few microns in length, and exhibit a branched geometry. Increasing the sweep rate to 50 mV/s produced longer nanofibers with a smaller average diameter of 200 nm. Nanofibers synthesized at 100 mV/s were noted to be smaller with an average and median diameter of 100 nm. These results illustrate the ease in which the morphology of nanostructured PANI can be altered and indicate that the method has the potential to create multi-diameter fibers or mixed-morphology materials.     

Collecting and processing records from the ultracentrifuge in "real-time" using an on-line computer

An analytical system consisting of an analytical cantrifuge coupled 'on-line' to a computer was assembled and tested. Collection of records from up to 9 solutions was achieved through programmes which sum readings to reduce noise as well as controlling the positioning of the scanner. With this system it was found that the limit on accuracy for molecular weights at concentrations less than 0.01 g cm-3 was +/- 3% estimated from sedimentation equilibrium experiments. The same system was used to collect records for similar concentrations from velocity experiments by employing a scanning schlieren. In this case the accuracy in estimating sedimentation coefficients was similar to those found when measuring photographs. Since the collection yields detailed information about the shape of the sedimenting boundary, the centroids of the boundary were routinely computed by second moment analysis rather than relying on the position of the maximum of the schlieren peak. In the same analysis estimates of diffusion coefficients were made routinely by calculating corrected height/area ratios for each scan. These calculations were made during the real-time of the experiment, so making available molecular parameters rather than records which must be evaluated some time after stopping the experiment.     

Report of the Treasurer: 1982. 90 Years of Balancing Budgets.

The APA Treasurer reports on the financial status of the Association. The purchase of Psychology Today in 1983 is noted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Saving Costs on Year 2000 Projects

The urgency of the year 2000 challenge is matched by the need to control the costs of what may be the largest IS task with no return on investment. Scaling back a year 2000 outsourcing project within acceptable levels of risk and breaking it down into three phases with targeted requests for proposal (RFPs) provides major cost savings and streamlines the bid-creation and vendor-selection process.     

Lot-to-order matching for a semiconductor assembly andtest facility

This paper is motivated by the problem of assigning semiconductor fabrication wafer lots to customer orders of various sizes. The goal of this research is to develop a method for deciding, on a given day, which orders to fill and the assignment of available lots to orders. This decision should be made in order to effectively utilize the capacity of the assembly/test facility, to minimize excess product that must be sent to a storage facility, and to maximize on-time delivery of customer orders. This problem can be formulated as an integer program with a nonlinear objective and nonlinear constraints. Because of the complexity of this formulation we decompose the problem into two integer linear programs and solve them in sequence by heuristic methods. The performance of the heuristic is analyzed using a representative data set. Based on this analysis, it is shown that our greedy heuristic performs significantly better than current practice.