Structural and transport effects of doping perfluorosulfonic acid polymers with the heteropoly acids, H3PW12O40 or H4SiW12O40

A perfluorosulfonic acid (PFSA) polymer with pendant side chain -O(CF₂)₄SO₃H was doped with the heteropoly acids (HPAs), H₃PW₁₂O₄₀ and H₄SiW₁₂O₄₀. Infrared spectroscopy revealed a strong interaction between the HPA and the PFSA ionomer. Modes associated with the peripheral bonds of the HPA were shifted to lower wave numbers when doped into PFSA membranes. Small-angle X-ray scattering (SAXS) measurements showed the presence of large crystallites of HPA in the membrane with d spacings of ca. 10 Å, close to the lattice spacing observed in bulk HPA crystals. Under wet conditions the HPA was more dispersed and constrained the size of the sulfonic acid clusters to 20 Å at a 5 wt% HPA doping level, the same as in the vacuum treated ionomer samples. Under conditions of minimum hydration the HPA decreased the E_a for the self-diffusion of water from 27 to 15 kJ mol⁻¹. The reverse trend was seen under 100% RH conditions. Proton conductivity measurements showed improved proton conductivity of the HPA doped PFSAs at a constant dew point of 80 °C for all temperatures up to 120 °C and at all relative hummidities up to 80%. The activation energy for proton conduction generally was lower than for the undoped materials at RH ≤80%. Significantly the E_a was 1/2 that of the undoped material at RHs of 40 and 60%. A practical proton conductivity of 113 mS cm⁻¹ was observed at 100 °C and 80% RH.     

Planar diffracted-beam interferometry/holography

A method to interfere planar electron diffracted beams that have been created by a primary electron beam passing through a crystal specimen has been invented and referred to as planar diffracted-beam interferometry/holography (planar DBI/H). Planar DBI/H is able to measure the intensity and coherence properties of the diffracted electron beams. When the diffracted electron beams are energy filtered, planar DBI/H is also able to measure the intensity and coherence properties of the zero-loss electrons, phonon-loss electrons and plasmon-loss electrons. These coherence properties are useful to help our understanding of the Stobbs factor and the properties of advanced materials, necessary for our understanding of nanoscience and the development of nanotechnology.     

Effect of crossed beams on Stokes gain and interaction length in stimulated Raman gain spectroscopy

We have numerically calculated the change in spatial resolution and Stokes gain for stimulated Raman gain experiments that use two crossed laser beams. The laser beams are modeled as diffraction-limited, Gaussian TEM(00) beams. Results for interaction length and relative Stokes gain are presented for crossing angles of 0-15°, focusing ?/#'s 2-250, and mismatches in the positions of the focal points of the two beams. The numerical results for spatial resolution and gain are compared with geometric approximations that have been previously published. These numerical simulations show where the approximations are valid and also extend into regions where the approximations are invalid. PACS: 42.65 Dr.     

National building stocks: addressing energy consumption or decarbonization?

The Building Research & Information special issue titled ‘Climate Change: National Building Stocks’ (2007) focused attention on the potential that the national building stock has in reducing CO₂ emissions. However, can this potential be realized? To do so requires faith in energy models that suggest that demolition, new build, and the refurbishing of existing homes with insulation measures can deliver massive energy savings by 2050. But why, in the future, can there be increased efficiency and reduced consumption, when this has never occurred in the past? It is argued that the central weakness in the special issue papers is the neglect of the relationship between energy consumption and energy efficiency, and of the ‘rebound effect’. The primary goal, should after all, be to reduce carbon emissions rather than energy use. Hence, emphasis should be placed on decarbonizing the centralized energy-supply systems. However, there will be a role here for micro-generation, building on the favourable image that energy efficiency has amongst the public. In 2050, we may be a low-carbon society, but I doubt we will be a low-energy one.

Le numéro spécial de Building Research & Information intitulé « Changement Climatique: le Parc Bâti National » (2007) a attiré l'attention sur le potentiel de réduction des émissions de CO₂ que possède le parc bâti national. Cependant, ce potentiel peut-il être réalisé? Pour y parvenir, il faut se fier à des modèles énergétiques qui suggèrent que les démolitions, les constructions neuves et une rénovation des logements existants s'accompagnant de mesures d'isolation peuvent assurer des économies d'énergie massives d'ici à 2050. Mais pourquoi y aurait-il à l'avenir un accroissement du rendement énergétique et une réduction de la consommation, alors que cela ne s'est jamais produit par le passé? Il est argumenté que le point faible central des articles de ce numéro spécial réside dans le fait qu'il n'est tenu compte ni de la relation entre consommation d'énergie et rendement énergétique, ni de « l'effet de rebond». Le but premier devrait être, après tout, de réduire les émissions de carbone plutôt que d'utiliser de l'énergie. De sorte que l'accent devrait être mis sur la décarbonisation des systèmes centralisés d'approvisionnement énergétique. Néanmoins, il y aura là un rôle à jouer pour la micro-génération, en tirant parti de l'image favorable que possède le rendement énergétique auprès du public. En 2050, nous serons peut-être une société à faible émission de carbone, mais je doute que nous devenions une société à faible consommation d'énergie.

Mots clés: parc bâti, changement climatique, démolitions, consommation d'énergie, rendement énergétique, faible émission de carbone, mesures politiques, effet de rebond     

Nonresonant referenced laser-induced thermal acoustics thermometry in air

We report a detailed investigation of nonresonant laser-induced thermal acoustics (LITA) for the single-shot measurement of the speed of sound (v(S)) in an oven containing room air. A model for the speed of sound that includes important acoustic relaxation effects is used to convert the speed of sound into temperature. A reference LITA channel is used to reduce uncertainties in v(S). Comparing thermocouple temperatures with temperatures deduced from our v(S) measurements and model, we find the mean temperature difference from 300 to 650 K to be 1% (+/-2sigma). The advantages of using a reference LITA channel are discussed.     

Selecting alabama waterway industrial sites for public development

Described is a numerical screening procedure to be used as an aid in determining which sites fronting on Alabama waterways should receive priority in the allocation of public development funds. The presented modeling procedure is an adaptation of a method for the evaluation of waterfront industrial site potential developed by the Regional Economic Development Center (REDC) at Memphis State University. Reasons for the revisions of the REDC effort are explained. In addition, model use procedures are introduced.     

Geodetic applications of GPS

The Global Positioning System (GPS) has become a widely used tool in geodetic studies of Earth. We review the principles of the applications of GPS to geodetic problems and discuss its applications to problems of global and regional geodesy. A global network of dual-frequency GPS receivers continuously tracks the GPS satellites and the data are distributed to globally accessible on-line archives with delays from a few hours to a few days. Analysis of these data occurs within a few days and the results are made available in the form of satellite ephemerides accurate to a few centimeters and receiver position estimates accurate to a few millimeters for weekly averaged positions. The collection and analysis of these data occurs under the auspices of the International GPS Service for Geodynamics (IGS) which maintains Internet-accessible archives in the United States and Europe. The data and analyzed results are used to study problems of global geodynamics with direct application to global plate tectonics and postglacial rebound and to studies of the the excitation of variations in Earth's rotation. When the global data are combined with data collected in a local region they can be used to study the deformation processes in that region. In the long run, analysis of these regional data will lend to improved dynamical models and to a better understanding of earthquakes and other deformation processes     

Earth Observing System AM1 mission to Earth

In 1998, NASA launches EOS-AMI, the first of a series of the Earth Observing System (EOS) satellites. EOS will monitor the evolution of the state of the earth for 18 years, starting with the morning observations of EOS-AM1 (10:30 a.m. equatorial crossing time). An integrated view of the earth, as planned by EOS, is needed to study the interchange of energy, moisture, and carbon between the lands, oceans, and atmosphere. The launch of EOS-AM1 and other international satellites marks a new phase of climate and global change research. Both natural and anthropogenic climate change have been studied for more than a century. It is now recognized that processes that vary rapidly in time and space-e.g. aerosol, clouds, land use, and exchanges of energy and moisture-must be considered to adequately explain the temperature record and predict future climate change. Frequent measurements with adequate resolution, as only possible from spacecraft, are key tools in such an effort. The versatile and highly accurate EOS-AM1 data, together with previous satellite records, as well as data from ADEOS, TRMM, SeaWiFS, ATSR, MERIS, ENVISAT, EOS-PM1, Landsat and ground-based networks is expected to revolutionize the way scientists look at climate change. This article introduces the EOS-AM1 mission and the special issue devoted to it. Following a brief historical perspective for an insight into the purpose and objectives of the mission, the authors summarize the characteristics of the five instruments onboard EOS-AM1. Specifically, they concentrate on the innovative elements of these five instruments and provide examples of the science issues that require this type of data     

Sex similarities in verbal and performance IQ deficits following unilateral cerebral lesions.

Investigated whether men and women produce similar Verbal IQ and Performance IQ patterns following unilateral cerebral lesions. Ss included 24 women (mean age 43.96 yrs) and 24 men (mean age 45.08 yrs) with independent neurological evidence of neoplastic or vascular lesions of the right cerebral hemisphere, 24 women (mean age 47.88 yrs) and 24 men (mean age 47.50 yrs) with such lesion evidence of the left cerebral hemisphere, and 14 female (mean age 46.43 yrs) and 14 male (mean age 45.50 yrs) controls. Each group was equated for education, lesion site, severity, chronicity, and etiology. Ss were administered the Wechsler-Bellevue Intelligence Scale, and differences in Verbal and Performance IQ values were compared. Contrary to reports in the literature, no consistent evidence of Sex?×?Lesioned Hemisphere interactions was found. Differences in the lateralization effects between men and women were not reflected in direction or pattern but only in magnitude, arguing against a theory of differential cognitive lateralization according to sex. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)