Evaluation of hydrogen and methanol fuel cell performance of sulfonated diels alder poly(phenylene) membranes

Hydrogen fuel cell performance of sulfonated diels alder poly(phenylene) (SDAPP) with IECs ≥ 1.8 meq g⁻¹ is comparable to Nafion 212 under fully humidified conditions at 80 °C. However, as relative humidity is reduced, performance loss is substantial for SDAPP when compared to Nafion 212. This loss can be attributed to the large drop in proton conductivity in SDAPP as relative humidity is reduced; the proton conductivity of SDAPP with an IEC of 2.3 meq g⁻¹ dropped from 0.117 S cm⁻¹ to 0.001 S cm⁻¹ as the relative humidity was reduced from 100% to 25% at 80 °C. Methanol fuel cell experiments using 3 M methanol result in a 60 mV performance improvement at 25 mA cm⁻² when using SDAPP with an IEC of 1.2 meq g⁻¹ instead of Nafion 212. This improvement is due to lower methanol permeability of SDAPP (1.4 meq g⁻¹) over Nafion 212, with SDAPP films having methanol permeabilities less than 25% of Nafion 212.     

High-performance and cost-effective membrane electrode assemblies for advanced proton exchange membrane water electrolyzers: Long-term durability assessment

Improved activity and durability performance of a two-cell (86 cm²) proton exchange membrane water electrolyzer (PEMWE) stack is reported for the first time. Both membrane electrode assemblies (MEAs) contain one order of magnitude lower platinum group metal (PGM) loadings compared to the state-of-the-art PEMWEs and incorporate novel Pt recombination layers. The high-performance and cost-effective MEAs are fabricated by the unique reactive spray deposition technology (RSDT). This advanced methodology allows for one-step fabrication of MEAs and ensures precise control and distribution of the catalyst composition and loading. The RSDT-fabricated MEAs contain only 0.2 and 0.3 mg_PGM cm^?2 loading in the cathode and anode electrodes, respectively, and demonstrate excellent activity and durability for over 3000 h of operation at industrially-relevant operating conditions without showing significant loss in performance. This novel work shows that a significant cost reduction for PEMWEs is achieved while maintaining excellent durability, high catalysts activities, and low hydrogen cross-over.     

Photosynthetic cathodes for Microbial Fuel Cells

One of the major limiting factors in the practical implementation of Microbial Fuel Cells is finding efficient and sustainable catalysts for the cathode half reaction, in an attempt to avoid expensive and/or toxic catalysts. The use of phototrophic organisms is one good option since they can act as efficient in-situ oxygenators thus facilitating the cathodic reaction. In the present study, the oxygen production by photosynthetic organisms was shown to be light dependant, which resulted in increasing the power generation by 42%. Furthermore, this study showed that a previously abiotic cathode that turned biotic showed a clear light response with an improved performance of 48%. Oxygen depletion in a water-based cathode can be avoided with the use of photosynthetic biocatalysts, thus providing sustainable operation for MFCs.     

Measurements of the slow drift dynamics of a model Pelamis wave energy converter

The Pelamis wave energy converter (WEC) is moored with a clump-assisted wire catenary of high compliance that, coupled with the displacement mass of Pelamis, has a resonant frequency an order of magnitude lower than the wave frequencies. The mooring is thus decoupled from first-order wave excitation, and is excited by second-order slowly varying drift forces, which are mainly due to the wave momentum transferred to the device as wave power is absorbed. The slow drift motion is damped by a combination of drag and wave-drift damping. This paper describes an experimental investigation of the slow-drift excitation and damping.     

Effects of dietary soybean oil on lipid and protein oxidation in pork patties during chill storage

The effect of dietary soybean oil on lipid and protein oxidation in low and high fat pork patties made from quadriceps femoris during chill storage in a high oxygen atmosphere packaging (80% O(2)/20% CO(2)) in the dark for 7 days was investigated. Pigs were fed either a standard diet or a diet added 2% soybean oil. After slaughter high fat pork patties were prepared for both feeding regimes by addition of back fat from pigs fed the same diet whereas low fat pork patties were prepared without addition of back fat. The 2% soybean diet increased the amount of unsaturated fat in the pork. Secondary lipid oxidation products determined as thiobarbituric acid reactive substances (TBARS) were found to increase in the pork patties with increased unsaturated fat. Increased unsaturated fat in the pork patties had no effect on protein oxidation determined as free protein thiol content and protein carbonyl content. A small, but significant increase in protein oxidation was found in the high fat pork patties independent on dietary fat. In conclusion, protein oxidation is unaffected by dietary fat in pork patties during chill storage for periods normally used in retail trade, and lipid and protein oxidation are not coupled under these conditions.     

Scale-up of single screw extruders

Scale-up from small laboratory size extruders to large production size extruders is a procedure of great practical importance. Many scale-up rules and theories have been proposed in the past, however it is not always clear how the different scale-up methods will affect extruder performance. A basic analysis of scale-up in plasticating single screw extruders is developed from which the effect of a certain scale-up strategy on extrusion performance can be evaluated in terms of solids conveying, melting, melt conveying, mixing, residence time, heat transfer, power consumption, and specific energy consumption. Various existing scale-up theories are evaluated and compared using the basic analysis. A number of existing scale-up theories have some significant drawbacks, in particular with non-constant specific energy consumption and imbalance between melting rate and pumping rate. Conditions that are desirable to achieve in scale-up are enumerated and ranked in terms of importance. This leads to two new scale-up methods that result in constant mechanical specific energy consumption and high throughput rates. The first scale-up method keeps the specific surface area constant. This scale-up should work well for high values of the Brinkman number. However, at low values of the Brinkman number, the melting rate may be insufficient. The second scale-up method keeps the melting rate at low Brinkman number equal to the pumping rate and, thus, should be useful in cases where the first scale-up method cannot be used.     

Integrated office communications

The office of the future will not be fully realised until all the functions required by users are integrated into one office system. The article proposes that this integration should be based on the integrated services local network. It discusses the reasons for integration, the technology behind integration, local area networks and teletex. It also examines the need for high-speed external communications, and how the ISLN could be the basis for a totally integrated office of the future.     

Assessment practices of health psychologists: Survey of APA Division 38 clinicians.

We surveyed the psychological assessment patterns of a random sample (700 sent, 270 returns: 40% adjusted return rate) of Division 38 members and fellows who were also in APA Division 12 or Division 29. Although general health assessment, neuropsychological assessment, and the assessment of depression were major areas of focus for these clinicians, the majority of testing was performed with a limited number of instruments, usually traditional techniques of assessment. The assessment of pain and evaluation of the aged were not major areas of concentration. Also, psychophysiological and brain-imaging procedures were found to be popular approaches used by health psychology clinicians. The implications of the findings are discussed in light of recent literature on health assessment practices. (PsycINFO Database Record (c) 2010 APA, all rights reserved)