Theoretical analysis of oxygen vacancies in layered sodium cobaltate Na_xCoO_{2-\delta}

Sodium cobaltate with high Na content is a promising thermoelectric material. It has recently been reported that oxygen vacancies can alter the material properties, reducing its figure of merit. However, experimental data concerning the oxygen stoichiometry are contradictory. We therefore studied the formation of oxygen vacancies in Na_xCoO_2 with first principles calculations, focusing on x = 0.75. We show that a very low oxygen vacancy concentration is expected at the temperatures and partial pressures relevant for applications.Comment: 4 page

Reaction kinetics of protons and oxide ions in LSM/lanthanum tungstate cathodes with Pt nanoparticle activation

Composite electrodes of La0.8Sr0.2MnO3 (LSM)/La28–xW4+xO54+3x/2 (x = 0.85, “LWO56”) on LWO56 electrolytes have been characterized by use of electrochemical impedance spectroscopy vs. pO2 and temperature from 900°C, where LWO56 is mainly oxide ion conducting, to 450°C, where it is proton conducting in wet atmospheres. The impedance data are analyzed in a model which takes into account the simultaneous flow of oxide ions and protons across electrolyte and electrodes, allowing extraction of activation energies and pre-exponential factors for the partial electrode reactions of protons and oxide ions. One composite electrode was infiltrated with Pt nanoparticles with average diameter of 5 nm, lowering the overall electrode polarization resistance (Rp) at 650°C from 260 to 40 Ω cm2. The Pt-infiltrated electrode appears to be rate limited by surface reactions with activation energy of ∼90 kJ mol−1 in the low temperature proton transport regime and ∼150 kJ mol−1 in the high temperature oxide ion transport regime. The charge transfer reaction, which makes a minor contribution to Rp, exhibits activation energies of ∼85 kJ mol−1 for both oxide ion and proton charge transfer

Creating an Inclusive Social Enterprise Ecosystem: A Policy Recommendation for the Growth of SE Sector in the Philippines

This policy paper highlights the critical roles of both public and private organizations in creating an enabling ecosystem for social enterprises to grow while striking a good balance in their social ,economic, and environmental bottom lines. It contains recommendations on the formation aspect of social entrepreneurs and the support mechanisms that need to be established by different stakeholders such as the academe, national government agencies, local government units, private institutions, and communities

Isolated testing of highly maneuverable inlet con cepts

Ten percent scale models of a Mach 2.2 two dimensional inlet and a Mach 2.0 axisymmetric inlet were tested in the NASA Lewis Research Center 8'x6' Supersonic Wind Tunnel as part of a cooperative effort with the McDonnell Aircraft Company. The objective of this effort was to test methods designed to increase the maneuvering performance of fighter aircraft inlets. Maneuvering improvement concepts were tested up to 40-deg angle of attack for Mach numbers of 0.6 and 0.9, and up to 25 deg for Mach numbers 1.2 and 1.4. Maneuvering improvement concepts included a rotating cowl lip, auxiliary inlets aft of the inlet throat, and a retracting centerbody for the axisymmetric inlet. Test results show that the rotating cowl design was effective in improving subsonic maneuvering performance for both inlets. Auxiliary inlets did not produce significant performance increases for either model. The retracted centerbody resulted in some performance benefits at high angles of attack. None of the maneuvering improvement concepts were effective at Mach 1.2 and 1.4

Dynamic response of multistory buildings

Two modern multistory buildings, one a five-story reinforced concrete building, the other a nine-story steel frame building, have been the subjects of an extensive series of dynamic tests. The vibrations of the buildings were induced by means of synchronized vibration exciters. The mathematical analysis needed in order to determine the stiffness and damping matrices from the experimentally determined modal properties of a structure has been developed. Three translational and one torsional mode of vibration of the reinforced concrete building were investigated in considerable detail. The damping in each mode and the resonant frequency was determined under various levels of excitation. Complete mode shapes were determined as well. The measurements of the resonant frequencies show a well-defined nonlinearity that can be well explained from the hysteretic material properties. The values of damping were for all modes approximately 276 with a tendency for the value of damping to increase with increasing force levels. A total of seven translational and three torsional modes of vibration of the nine-story steel frame building were investigated in detail. A mode in which the floor slabs vibrate horizontally as free-free beams was excited as well. The lowest translational modes in the two principal directions of the building had damping values of about 0.516. The second lowest translational modes had damping values of approximately 1.0016. For both buildings the damping values are considerably less than the values usually mentioned in the literature. Since most earlier tests used run-down tests rather than the steady-state tests used in the present work, comparison tests were run to explore possible differences in the test results. It was concluded that run-down tests could easily overestimate the values of damping by several hundred per cent. A new method for the measurements of natural periods of vibration of structures is proposed. The new method has several important advantages over wind-excited vibration tests which have been used extensively in the past to measure the natural periods of vibration of structures

Implementation of an Exercise Program in Assisted Living

Assisted living facilities are increasingly becoming a popular option for aging individuals. One thing found lacking in these facilities is a structured exercise program. In a review of literature, it was found that strength training programs have resulted in an improvement in elders\u27 functional performance. It has been shown that an older adult can successfully perform strength training exercises. Strength training exercises can add muscle, increase strength, and enhance the elders\u27 flexibility. This improved functional performance plays a significant role in the elders\u27 ability to maintain their independence with ADLs (activities of daily living), which may result in a better quality of life A strength training exercise program for assisted living individuals was developed based on extensive literature review and presented to assisted living staff for implementation. The goal of the developed program is to maintain or even improve the elderly person\u27s gait, strength, and/or mobility to maintain their independence for as long as possible and to enhance their quality of lif

Past and Present Molluscan Fauna, Sheyenne River, North Dakota

Mollusks of the Sheyenne River in eastern North Dakota were studied during the summer of 1966. Both living mollusks from the river and fossil forms from the exposed terrace sediments were collected. Nine species of mussels presently occur in the Sheyenne River: Fusconaia flava (Rafinesque), Amblema costata Rafinesque , Lasmigona compressa (Lea), L. complanata (Barnes), Anodonta grandis Say, Anodontoides ferussacianus (Lea), Strophitus rugosus (Swainson), Lampsilis siliquoidea (Barnes), and L. ventricosa (Barnes). Three other species, Quadrula quadrula Rafinesque, Proptera alata (Say) and Ligumia recta latissima (Rafinesque) occur only as fossils in terrace sediments. Nine genera of gastropods and fingernail clams (sphaeriids) now exist in the river. These same nine genera have also been collected from river terrace sediments. Long periods of no flow, high alkalinity, high turbidity, unavailability of the proper fish host, and small low-water check dams may be possible factors limiting the mussel distribution in the Sheyenne River. Some of these factors may also limit the gastropod and sphaeriid distribution. Long periods of no flow is perhaps a limiting factor in the upper reaches of the river. High alkalinity may also be another limiting factor in the upper reaches. High turbidity in the lower reaches appears to be a limiting factor here. The absence of particular fish hosts for mussels and small low-water check dams may be significant limiting factors in the upper reaches above Baldhill Dam. A comparison between the present and fossil gastropods and sphaeriids suggest that no appreciable faunal change has occurred. In comparing the present and fossil mussel fauna, three species, Quadrula quadrula, Proptera alata, and Ligumia recta latissima, were found only as fossils. These three species presently occur in the Red River Valley only in rivers of significantly greater discharge. This suggests that the Sheyenne River had a greater discharge at times in the past