Fuel cell micro-CHP techno-economics: Part 2 – Model application to consider the economic and environmental impact of stack degradation

This article presents a literature review regarding the mechanisms of fuel cell degradation, accompanied by the reported range of observed degradation rates in experimental, demonstration and early commercial systems. It then synthesises and exploits this information to investigate the influence of degradation on the economic and environmental credentials of fuel cell micro-combined heat and power (micro-CHP) for the UK residential sector. The investigation applies a techno-economic model developed in the companion article designed to demarcate the key characteristics of commercially successful systems. Two distinct modes of degradation are examined; one proportional to power density in the stack, and the other proportional to thermal-cycling rate of the stack. It is found that limiting the power-density related degradation rate is very important from economic and environmental viewpoints, but thermal-cycling related degradation is less important when thermal energy storage is available because cycling can be avoided. Furthermore it is noted that techno-economic studies that ignore degradation can overestimate the marginal value of a micro-CHP system with respect to the conventional alternative by up to 45% and the CO₂ emissions reduction potential by up to 57%, for performance degradation rates of 2% per MW_eh output. This conclusion is noteworthy because most techno-economic analyses of fuel cells ignore degradation, potentially providing misleading results. Finally it is concluded that existing commercial degradation targets, such as the SECA targets, are appropriate for achieving marketable systems.     

Robotic Assembly of Space Solar-Power Facilities

This paper profiles research relating to the robotic assembly, inspection, and maintenance of space solar-power facilities. Free-flying robots, fixed-base manipulators, and attached mobile manipulators are examined, the technical challenges facing them are outlined, and their roles in the construction process are illuminated. Themes include autonomous materials delivery, warehousing, large-scale payload handling and mating, payload attachment in confined spaces, and inspection. Research has addressed a fraction of the technologies needed to perform reliable autonomous assembly, inspection, and maintenance. Areas in need of further development are examined and potential research is outlined. Current technology cannot fulfill the requirements of orbital construction. The research and development needed can be completed in the near future, and substantive assembly inspection and maintenance can be achieved.     

The antecedents and correlates of agreeableness in adulthood.

Data from a 25-year prospective study of 194 individuals indicated that teacher and peer reports of aggression, compliance, and self-control at age 8 distinguished high-agreeable from low-agreeable adults at age 33. Profile analyses revealed two behavioral types in childhood and two personality types in adulthood, with considerable continuity in the composition of these high- and low-agreeable types over time. High-agreeable childhood types had fewer disobedience and concentration problems than low-agreeable childhood types, and among boys, high-agreeable childhood types had better school grades and fewer behavior problems than their low-agreeable counterparts. High-agreeable adulthood types reported less alcoholism and depression, fewer arrests, and more career stability than did low-agreeable adulthood types. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing the Validity of Implicit Egotism: A Reply to Gallucci (2003).

B. W. Pelham, M. C. Mirenberg, and J. T. Jones (see record 2002-12744-001) argued that most people prefer stimuli that are associated with the self, a preference they called implicit egotism. In support of implicit egotism, Pelham et al presented evidence from 10 archival studies showing that people gravitate toward careers and places of residence that resemble their names or birthday numbers. M. Gallucci (see record 2003-09138-001) argued that alternate analyses of the same data provide strong evidence against implicit egotism. Whereas Gallucci was correct that Pelham et al's original analyses were flawed, their results remain significant even when more conservative tests are used. The authors also present new data in support of implicit egotism, including exhaustive studies of (a) common surnames and US city names and (b) common surnames and street names. The new studies also revealed that as sample sizes grow larger, studies are more likely to produce evidence of implicit egotism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A simulation study of long throw sputtering for diffusion barrierdeposition into high aspect vias and contacts

Modified sputtering techniques, such as long throw sputtering, collimation, and ionized sputtering, have been proposed to improve VLSI topography bottom coverage by narrowing the angular distribution of the sputter flux at the substrate and reducing subsequent flux shadowing at the bottom of topography. This paper first investigates a number of unique aspects involved in the simulation of long throw sputter systems. In particular, time importance of inhomogeneous film density and nonunity sticking coefficients are addressed. The second part of the paper presents a simulation study of long throw sputtering, providing a comparison to collimated and standard sputtering systems. The simulations are performed using the SIMSPUD/SIMBAD ballistic deposition tool. SIMSPUD is used to study film uniformity over a 300-mm wafer and to generate angular distributions at the center and edge of the wafer. The ability of SIMBAD to simulate directed sputtering systems is verified by direct comparison to Ti films deposited into oxide trenches. The importance of modeling the film microstructure is demonstrated by comparison between cross-sectional SEM's micrograph for evaporation and modeling results, such as long throw sputtering with a variety of substrate/target spacings, typical “standard” as well as “collimated” systems. SEM's of overhang structures and simulations are also presented to demonstrate nonunity sticking during the co-sputtering of TiW     

Negative affectivity and the reporting of stressful life events.

Replicated D. T. Lykken's study (see record 1968-18058-001) to resolve the conflict between the findings of S. R. Maddi et al (see record 1987-22446-001) and those of D. H. Schroeder and P. T. Costa (see record 1984-23643-001) regarding the impact of negative affectivity (NA; i.e., neuroticism) contaminated life event items on observed life event–illness relationships. Among 330 managers and professionals, NA-contaminated items correlated significantly with 3 measures of well-being (depression, life satisfaction, and physical symptoms). In 2 of 3 cases, correlations between contaminated items and well-being measures were significantly different from correlations between uncontaminated items and well-being indicators. Prior life event–well-being findings may be inflated considerably by the use of NA-contaminated events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Screening of elemental impurities in commercial detonation nanodiamond using sector field inductively coupled plasma-mass spectrometry

The quantitation of 55 elemental impurities in 15 commercial samples of detonation nanodiamond (DND), micron-sized diamond of high pressure/high temperature synthesis and detonation synthesis soot (DS) was achieved using a direct sector field ICP-MS analytical method. A set of 23 elements contributing more than 99.8 mass % of all impurities was selected and used as markers for the evaluation of DND purity. Obtained data were evaluated to identify important information on possible sources of nanodiamond contamination during purification, disaggregation, solubilisation or stabilisation of suspensions. Distinctive groups of elements (including Cr, Mn and S; Mo, W, V and Ti; Na, B and Si; Ca and Mg) occurring at elevated levels in DND can be readily visualised using radar plots, and can be related to the detonation synthesis (construction materials of explosion chamber, admixture in coolant, detonator type) and/or purification processes (type of oxidation process and reagents). The contaminant profile for each respective DND can be also considered as a fingerprint, characteristic for every producer and technology used. Results obtained also highlight how DND can be considered as effective collectors of various inorganic impurities from chemical reagents, glassware, sonotrode and other materials used during processing, including disaggregation and stabilisation of suspensions.     

Evaluating the role of vegetation on the transport of contaminants associated with a mine tailing using the Phyto-DSS

We identified contaminants associated with the Cata mine tailing depot located in the outskirts of the city of Guanajuato, Mexico. We also investigated strategies for their phytomanagement. Silver and antimony were present at 39 and 31 mg kg(-1), respectively, some twofold higher than the Dutch Intervention Values. Total and extractable boron (B) occurred at concentrations of 301 and 6.3 mg L(-1), respectively. Concentrations of B in soil solution above 1.9 mg L(-1) have been shown to be toxic to plants. Plant growth may also be inhibited by the low concentrations of extractable plant nutrients. Analysis of the aerial portions of Aloe vera (L. Burm.f.) revealed that this plant accumulates negligible concentrations of the identified contaminants. Calculations using a whole system model (Phyto-DSS) showed that establishing a crop of A. vera would have little effect on the drainage or leaching from the site. However, this plant would reduce wind and water erosion and potentially produce valuable cosmetic products. In contrast, crops of poplar, a species that is tolerant to high soil B concentrations, would mitigate leaching from this site. Alternate rows of trees could be periodically harvested and be used for timber or bioenergy.     

Controlled synthesis of gold nanoparticles by fluorescent light irradiation

A novel photochemical synthesis of size-controlled gold nanoparticles was reliably accomplished via both a direct reduction and a seeded-growth method at room temperature under the irradiation of fluorescent light. These methods utilized the intensity of fluorescent light that closely resembles daily sunlight (～100 mW cm(-2)). This effectively allowed for the formation of gold nanoparticles with tunable sizes simply by controlling the concentration of trisodium citrate and gold chloride. The broad band fluorescent light was found to be an efficient source for inducing the formation of gold nanoparticles at ambient conditions. The size distribution and absorption property of the resulting nanoparticles were thoroughly characterized by scanning/transmission electron microscopy, dynamic light scattering, UV-visible spectroscopy and powder x-ray diffraction. This photochemical synthesis demonstrates, for the first time, the reliable preparation of gold nanoparticles at room temperature upon irradiation with fluorescent light.     

Indium tin oxide nanopillar electrodes in polymer/fullerene solar cells

Using high surface area nanostructured electrodes in organic photovoltaic (OPV) devices is a route to enhanced power conversion efficiency. In this paper, indium tin oxide (ITO) and hybrid ITO/SiO(2) nanopillars are employed as three-dimensional high surface area transparent electrodes in OPVs. The nanopillar arrays are fabricated via glancing angle deposition (GLAD) and electrochemically modified with nanofibrous PEDOT:PSS (poly(3,4-ethylenedioxythiophene):poly(p-styrenesulfonate)). The structures are found to have increased surface area as characterized by porosimetry. When applied as anodes in polymer/fullerene OPVs (architecture: commercial ITO/GLAD ITO/PEDOT:PSS/P3HT:PCBM/Al, where P3HT is 2,5-diyl-poly(3-hexylthiophene) and PCBM is [6,6]-phenyl-C(61)-butyric acid methyl ester), the air-processed solar cells incorporating high surface area, PEDOT:PSS-modified ITO nanoelectrode arrays operate with improved performance relative to devices processed identically on unstructured, commercial ITO substrates. The resulting power conversion efficiency is 2.2% which is a third greater than for devices prepared on commercial ITO. To further refine the structure, insulating SiO(2) caps are added above the GLAD ITO nanopillars to produce a hybrid ITO/SiO(2) nanoelectrode. OPV devices based on this system show reduced electrical shorting and series resistance, and as a consequence, a further improved power conversion efficiency of 2.5% is recorded.