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.     

Stereological measurement and error estimates for three-dimensional fiber orientation

A method is presented for measuring three-dimensional fiber orientation in fiber-reinforced polymers and placing confidence limits on the results. The orientations of individual fibers are determined from the elliptical intersections between the cylindrical fibers and a polished section. This can be done using either manual digitization or automated image analysis. Volume averages for the sample are computed using an orientation-dependent weighting function that corrects for the bias of an area-based sample. Equations are developed for nonuniform fiber lengths, using both number-average and weight-average measures of orientation. Sources of systematic, measurement, and sampling error are discussed and equations for sampling error and the propagation of measurement error are derived. The results use a second-rank tensor to characterize fiber orientation, but the error analysis can be applied to any type of orientation parameter. We implement the technique using manual digitization of optical micrographs. Our implementation accurately measures samples with known orientation, and produces identical results from two perpendicular sections of a glass fiber/nylon injection-molded sample.     

大奥马哈包装公司办公楼设计

Greater Omatha Packing(GOP)公司新建了一套肉类包装设施，以护大其目前的处理能力.随着工厂经营运作的开展,对销售和支持服务的需求也随之而来.     

Formation of ethanol from carbon monoxide via a new microbial catalyst

A recently discovered clostridial bacteria converts components of synthesis gas (CO, CO₂, H₂) into liquid products such as ethanol, butanol and acetic acid. Isolated from an agricultural lagoon, the stability and productivity characteristics of the bacteria were studied in a continuous 4.5 l bubble column bioreactor at 37°C using artificial blends of CO, CO₂, and N₂. Preliminary results on the rates of cell growth, substrate utilization, product formation, and yields of products and cells from CO are discussed. At steady state, apparent yields (mole C in products per mole CO consumed) of ethanol, butanol, and acetic acid were 0.15, 0.075 and 0.025, respectively, and the cell yield was 0.25 g/mol CO. The theoretical yield of ethanol is 0.33 if CO is only utilized for the production of ethanol. The experimental yield of CO₂ from CO was approximately 60% compared to the theoretical yield of 67% with ethanol as the sole product. As a comparison with another ethanol-producing bacteria, the results of a similar fermentation study using batch-grown Clostridium ljungdahlii showed yields of 0.062 for ethanol and 0.094 for acetic acid and a cell yield of 1.378 g/mol.     

Understanding the Development‐Organizing Dialectic

Abstract: Can community organizing and community development be practiced in combination through community development corporations (CDCs)? While community organizing and community development have complementary goals, they are based on potentially contradictory worldviews and occupy potentially contradictory social structural locations. Whether the two strategies can be combined in a single organization without causing severe disruption is questionable. A three‐year historical and comparative case study of CDCs involved in the Toledo Community Organizing Training and Technical Assistance Program shows the challenges faced by CDCs attempting to combine organizing and development. The analysis traces changes in the program and the CDCs through honeymoon, conflict, and resolution stages. Of the three CDCs that began the program, one dropped out early, another continued organizing as long as the program continued but then ended its organizing efforts, and a third continued its organizing efforts. The analysis confirms the dialectical relationship between community organizing and community development, showing how the two continuing CDCs differed in their contradictive management strategies.     

Introduction: Psychology's view of managed care.

This introduction to the series of surveys on psychologist reactions to managed care presents an overview of the topics, findings, and conclusions of these surveys done through the American Psychological Association's Practice Directorate, Division 42, and the New Jersey Psychological Association. The results of these studies give a meaningful base for references to psychologist attitudes and reactions to the force of managed care on the profession. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Academic underachievement and the disruptive behavior disorders": Correction.

Reports an error in the original article by P. J. Frick et al (Journal of Consulting and Clinical Psychology, 1991, Vol 59[2], 289–294). The correct formula to calculate the discrepancy score between IQ and academic achievement, Step 3, is provided. (The following abstract of this article originally appeared in record 1991-21350-001.) Academic underachievement (AU) was studied among 177 clinic-referred boys (aged 7–12 yrs) reliably diagnosed as having attention-deficit hyperactivity disorder (ADHD) or conduct disorder (CD). Unlike previous studies, the present study assessed AU using a formula that determined the discrepancy between a child's predicted level of achievement and actual level of achievement while controlling for regression and age effects. AU was associated with both ADHD and CD when the disorders were examined individually. However, when examined in multivariate logit model analyses, the apparent relation between CD and AU was found to be due to its comorbidity with ADHD. When boys with ADHD were divided into those with attention deficits only and those with co-occurring hyperactivity, findings did not support the hypothesis that the association with AU is stronger for attention deficits without co-occurring hyperactivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)