Ion transport within random-sulfonated and block-sulfonated copolyimides

A series of sulfonated copolyimides was prepared from 4,4-oxydianiline, sulfonated 4,4′-oxydianiline, and 4,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride). Both random- and block structures were prepared by varying the timing of monomer addition to the polymerization reaction. The polymers were converted to their acid forms and then cast into films. ¹H NMR, FTIR, and non-aqueous titration verified the degree of polymer sulfonation. The block copolymers showed higher water uptake and proton conductivities than random copolymers with similar ion exchange capacity (IEC) values. These differences became pronounced as the IEC value was increased.     

Liquid flow texture analysis in trickle bed reactors using high-resolution gamma ray tomography

Trickle bed reactor performance and safety may suffer from radial and axial liquid maldistribution and thus from non-uniform utilization of the catalyst packing. Therefore, experimental analysis and fluid dynamic simulation of liquid–gas flow in trickle bed reactors is an important topic in chemical engineering. In the present study for the first time a truly high-resolution gamma ray tomography technique was applied to the quantitative analysis of the liquid flow texture in a laboratory cold flow trickle bed reactor of 90 mm diameter. The objective of this study was to present the comparative analysis of the liquid flow dynamics for two different initial liquid distributions and two different types of reactor configurations. Thus, the hydrodynamic behavior of a glass bead packing was compared to a porous Al₂O₃ catalyst particle packing using inlet flow from a commercial spray nozzle (uniform initial liquid distribution) and inlet flow from a central point source (strongly non-uniform initial liquid distribution), respectively. The column was operated in downflow mode at a gas flow rate of 180 L h⁻¹ and at liquid flow rates of 15 and 25 L h⁻¹.     

The Role of Oxygen Storage in NO Conversion in Automotive Catalysts

An asymmetry in NO conversion efficiency is apparent during trans-stoichiometric air–fuel ratio steps over a three-way catalyst. After a lean-to-rich step, NO conversion becomes high very rapidly and asymptotes to a higher value, followed by a reduction to a high, but reduced level. Following a rich-to-lean step, conversion remains high for a period before gradually decreasing to the low level seen at steady lean operation. This dynamic response in NO conversion can be modelled by a three-way catalyst model which includes ceria reoxidation by way of NO dissociative adsorption. Five, periodic, different aspect triangular waveforms were tested to try to exploit the asymmetry by waveform shaping. No strong trends in average NO conversion efficiency resulted; however, some shapes seemed to give a better overall conversion.     

Psychological factors, rehabilitation adherence, and rehabilitation outcome after anterior cruciate ligament reconstruction.

Objective: To examine prospectively the relationships among psychological factors, rehabilitation adherence, and short-term rehabilitation outcome after knee surgery. Study Design and Participants: Individuals with acute anterior cruciate ligament (ACL) tears (N?=?95) completed measures of self-motivation, social support, athletic identity, and psychological distress before reconstructive surgery. After surgery, 93 participants reported on their completion of home rehabilitation exercises and cryotherapy, and their rehabilitation practitioners indicated the patients' attendance at, and adherence during, rehabilitation sessions. Rehabilitation outcome measures were taken from 69 participants approximately 6 months postsurgery. Main Outcome Measures: Knee laxity, functional ability, and subjective symptoms were the primary outcomes assessed. Results: Self-motivation was significant predictor of home exercise completion; athletic identity and psychological distress were significant predictors of knee laxity; and attendance at rehabilitation sessions and home cryotherapy completion were significant predictors of functional ability. Rehabilitation adherence did not mediate the relationship between psychological factors and rehabilitation outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Silolasten nach der neuen DIN 1055‐6

Silo loads according to the new DIN 1055‐6 An overview and some background information are given to the new DIN 1055‐6 “Actions on Structures: Actions on Silos and Tanks”. Following the rules of EN 1991‐4 the determination of silo loads is adjusted to the new safety philosophy of DIN 1055‐100. In some cases new load rules have been introduced or existing rules have been replaced. In particular this concerns patch loads for thin‐walled steel silos, loads in squat and intermediate standard silos, hopper loads or loads for large eccentricity of discharge.     

Further investigation of common knowledge effects on job analysis ratings.

Previous research (Smith & Hakel, 1979) raised the possibility that the Position Analysis Questionnaire (PAQ) only captures common knowledge, or stereotypes, about jobs. Cornelius, DeNisi, and Blencoe (1984) presented data to refute this, but found that the number of PAQ items rated does not apply (DNA) was related to the agreement between naive raters and expert raters. The present study used data from 87 analysts and 24 jobs. Naive ratings were those obtained from analysts who had not studied the job, whereas expert ratings were those obtained from raters who had observed the job, interviewed incumbents, and written task statements describing the job. These ratings were then compared to target-score profiles obtained from PAQ services. Results confirmed earlier hypotheses that large numbers of DNA items artifactually inflate correlational estimates of agreement between expert and naive raters. In addition to this artifact, results also supported the view that the PAQ is less appropriate as a job analysis tool for some types of jobs. Implications for research and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of Subcycle Electro-Optic Sampling Without Background

Journal of Infrared, Millimeter, and Terahertz Waves - We explore background-free options to detect mid-infrared (MIR) electric transients. The MIR field and a near-infrared probe interact via sum-...