The First Step in Solar Hydrogen Production: Development of a Solar Thermal Reactor for the Reduction of Metal Oxide Particles

A solar thermal reactor has been designed to experimentally investigate promising paths for reducing metal oxide particles to reduced oxidation states (e.g. Fe2O3 to Fe3O4) utilizing concentrated solar energy. This reactor is windowless and is able to handle internal cavity temperatures in excess of 1700 K. It also has a quasi-continuous feed system that allows the particle residence times to be varied for particles between 0.044 mm and 1 mm in diameter. Furthermore, this reactor utilizes an instrumentation system for the measurement of temperature, particle residence time, particle mass flow rate, and solar flux. In an industrial setting, a large-scale metal oxide reactor would serve as the first step in a metal oxide solar thermal electro-chemical cycle. After the particles are reduced at elevated temperatures using concentrated solar energy, they are used in an electrolysis process to facilitate the production of hydrogen from water. In this process, the reduced metal oxide particles are reoxidized at the anode and hydrogen is liberated at the cathode. The presence of the metal oxide enables hydrogen to be produced with an ideal cell potential of 0.21 V, a potential substantially below the ideal value of 1.2 V for traditional water electrolysis

The First Step in Solar Hydrogen Production: Development of a Solar Thermal Reactor for the Reduction of Metal Oxide Particles

A solar thermal reactor has been designed to experimentally investigate promising paths for reducing metal oxide particles to reduced oxidation states (e.g. Fe2O3 to Fe3O4) utilizing concentrated solar energy. This reactor is windowless and is able to handle internal cavity temperatures in excess of 1700 K. It also has a quasi-continuous feed system that allows the particle residence times to be varied for particles between 0.044 mm and 1 mm in diameter. Furthermore, this reactor utilizes an instrumentation system for the measurement of temperature, particle residence time, particle mass flow rate, and solar flux. In an industrial setting, a large-scale metal oxide reactor would serve as the first step in a metal oxide solar thermal electro-chemical cycle. After the particles are reduced at elevated temperatures using concentrated solar energy, they are used in an electrolysis process to facilitate the production of hydrogen from water. In this process, the reduced metal oxide particles are reoxidized at the anode and hydrogen is liberated at the cathode. The presence of the metal oxide enables hydrogen to be produced with an ideal cell potential of 0.21 V, a potential substantially below the ideal value of 1.2 V for traditional water electrolysis

2009 Progress Report on the Economic Well-Being of Working Age People with Disabilities

This progress report on the prevalence rate, employment, poverty, and household income of working-age people with disabilities (ages 21-64) uses data from the 2008 and earlier Current Population Surveys – Annual Social and Economic Supplement (CPS-ASES, a.k.a. Annual Demographic Survey, Income Supplement, and March CPS). The CPS is the only data set that provides continuously-defined yearly information on the working-age population with disabilities since 1981

2010 Progress Report on the Economic Well-Being of Working-Age People with Disabilities

This progress report on the prevalence rate, employment, poverty, and household income of working-age people with disabilities (ages 21-64) uses data from the 2010 and earlier Current Population Surveys – Annual Social and Economic Supplement (CPS-ASES, a.k.a. Annual Demographic Survey, Income Supplement, and March CPS). The CPS is the only data set that provides continuously-defined yearly information on the working-age population with disabilities since 1981

Development of a Solar Rotary-Kiln Reactor for the Reduction of Metal Oxide Particles

A solar rotary-kiln reactor has been fabricated for the reduction of metal oxide particles at ~1650 K as part of a solar thermal decoupled water electrolysis process for the production of hydrogen. Particle motion is controlled through the reactor’s angular speed of rotation. At rotational speeds greater than 65 rpm, the internal walls of the reactor are fully covered with particles. Simultaneously, mixing elements generate a particle cloud in the reactor in order to increase the absorption of incident solar radiation. A model of the reactor that solves the energy conservation equation and includes the kinetics of the metal oxide reduction suggests that peak thermal efficiencies of 47 percent are possible for the reduction of hematite to magnetite. In parallel, the solid state kinetics for the reduction of cobalt oxide (a promising alternative to iron oxide) in a low oxygen partial pressure atmosphere has been determined. Reduction follows the shrinking core model and is initially limited by the rate of oxygen diffusion in the gas phase and later limited by the chemical kinetics at the shrinking reactive interface. Regression of the model to isothermal and non-isothermal thermogravimetric analyzer data yielded the temperature-dependent reaction rate parameters

Treatment of diabetic retinopathy through neuropeptide Y-mediated enhancement of neurovascular microenvironment

Diabetic retinopathy (DR) is one of the most severe clinical manifestations of diabetes mellitus and a major cause of blindness. DR is principally a microvascular disease, although the pathogenesis also involves metabolic reactive intermediates which induce neuronal and glial activation resulting in disruption of the neurovascular unit and regulation of the microvasculature. However, the impact of neural/glial activation in DR remains controversial, notwithstanding our understanding as to when neural/glial activation occurs in the course of disease. The objective of this study was to determine a potential protective role of neuropeptide Y (NPY) using an established model of DR permissive to N‐methyl‐D‐aspartate (NMDA)‐induced excitotoxic apoptosis of retinal ganglion cells (RGC) and vascular endothelial growth factor (VEGF)‐induced vascular leakage. In vitro evaluation using primary retinal endothelial cells demonstrates that NPY promotes vascular integrity, demonstrated by maintained tight junction protein expression and reduced permeability in response to VEGF treatment. Furthermore, ex vivo assessment of retinal tissue explants shows that NPY can protect RGC from excitotoxic‐induced apoptosis. In vivo clinical imaging and ex vivo tissue analysis in the diabetic model permitted assessment of NPY treatment in relation to neural and endothelial changes. The neuroprotective effects of NPY were confirmed by attenuating NMDA‐induced retinal neural apoptosis and able to maintain inner retinal vascular integrity. These findings could have important clinical implications and offer novel therapeutic approaches for the treatment in the early stages of DR

Periodic solutions and refractory periods in the soliton theory for nerves and the locust femoral nerve

Close to melting transitions it is possible to propagate solitary electromechanical pulses which reflect many of the experimental features of the nerve pulse including mechanical dislocations and reversible heat production. Here we show that one also obtains the possibility of periodic pulse generation when the boundary condition for the nerve is the conservation of the overall length of the nerve. This condition generates an undershoot beneath the baseline (`hyperpolarization') and a `refractory period', i.e., a minimum distance between pulses. In this paper, we outline the theory for periodic solutions to the wave equation and compare these results to action potentials from the femoral nerve of the locust (locusta migratoria). In particular, we describe the frequently occurring minimum-distance doublet pulses seen in these neurons and compare them to the periodic pulse solutions.Comment: 10 pages, 6 Figure

Giant peroxisomes in a moss (Physcomitrella patens) peroxisomal biogenesis factor 11 mutant

Peroxisomal biogenesis factor 11 (PEX11) proteins are found in yeasts, mammals and plants, and play a role in peroxisome morphology and regulation of peroxisome division. The moss Physcomitrella patens has six PEX11 isoforms which fall into two subfamilies, similar to those found in monocots and dicots. We carried out targeted gene disruption of the Phypa_PEX11-1 gene and compared the morphological and cellular phenotypes of the wild-type and mutant strains. The mutant grew more slowly and the development of gametophores was retarded. Mutant chloronemal filaments contained large cellular structures which excluded all other cellular organelles. Expression of fluorescent reporter proteins revealed that the mutant strain had greatly enlarged peroxisomes up to 10 μm in diameter. Expression of a vacuolar membrane marker confirmed that the enlarged structures were not vacuoles, or peroxisomes sequestered within vacuoles as a result of pexophagy. Phypa_PEX11 targeted to peroxisome membranes could rescue the knock out phenotype and interacted with Fission1 on the peroxisome membrane. Moss PEX11 functions in peroxisome division similar to PEX11 in other organisms but the mutant phenotype is more extreme and environmentally determined, making P. patens a powerful system in which to address mechanisms of peroxisome proliferation and division