Phase Diagram of Li_xFePO_4

The phase diagram for LixFePO4 has been determined for different lithium concentrations and temperatures. The two low-temperature phases, heterosite and triphylite, have previously been shown to transform to a disordered solid solution at elevated temperatures. This disordered phase allows for a continuous transition between the heterosite and triphylite phases and is stable at relatively low temperatures. At intermediate temperatures the proposed phase diagram resembles a eutectoid system, with eutectoid point at around x=0.6 and 200°C. Kinetics of mixing and unmixing transformations are reported, including the hysteresis between heating and cooling. The enthalpy of this transition is at least 700 J/mol

Practical considerations in aeroelastic design

The structural design process for large transport aircraft is described. Critical loads must be determined from a large number of load cases within the flight maneuver envelope. The structural design is also constrained by considerations of producibility, reliability, maintainability, durability, and damage tolerance, as well as impact dynamics and multiple constraints due to flutter and aeroelasticity. Aircraft aeroelastic design considerations in three distinct areas of product development (preliminary design, advanced design, and detailed design) are presented and contrasted. The present state of the art is challenged to solve the practical difficulties associated with design, analysis, and redesign within cost and schedule constraints. The current practice consists of largely independent engineering disciplines operating with unorganized data interfaces. The need is then demonstrated for a well-planned computerized aeroelastic structural design optimization system operating with a common interdisciplinary data base. This system must incorporate automated interfaces between modular programs. In each phase of the design process, a common finite-element model for static and dynamic optimization is required to reduce errors due to modeling discrepancies. As the design proceeds from the simple models in preliminary design to the more complex models in advanced and detailed design, a means of retrieving design data from the previous models must be established

Seasonal trends in response to inoculation of coast live oak with Phytophthora ramorum

We developed a branch cutting inoculation method to provide a controlled system for studying variation in response to inoculation of coast live oak (Quercus agrifolia) with Phytophthora ramorum. This method has advantages over inoculations of trees in the field, in containing the inoculum and in allowing high levels of replication and the possibility of time series of responses. We previously reported significant tree-to-tree variation, with little population variation in lesion size using this method (Dodd and others 2005). Here we report on a time series in which branch cuttings were collected from the same trees at eight dates through a full year cycle. Branch cuttings were sampled from 33 trees from two sites at China Camp in Marin County, California, including 18 trees from one site that had suffered heavy mortality from this disease (Miwok Meadows) and 15 trees from a second site that has had little infection (Chicken Coop Island)

Mössbauer Spectrometry Study of Thermally-Activated Electronic Processes in Li_xFePO_4

The solid solution phase of Li_xFePO_4 with different Li concentrations, x, was investigated by Mössbauer spectrometry at temperatures between 25 and 210 °C. The Mössbauer spectra show a temperature dependence of their isomer shifts (E_(IS)) and electric quadrupole splittings (E_Q), typical of thermally activated, electronic relaxation processes involving ^(57)Fe ions. The activation energies for the fluctuations of E_Q and E_(IS) for Fe^(3+) are nearly the same, 570 ± 9 meV, suggesting that both originate from charge hopping. For the Fe^(2+) components of the spectra, the fluctuations of E_Q occurred at lower temperatures than the fluctuations of E_(IS), with an activation energy of 512 ± 12 meV for E_Q and one of 551 ± 7 meV for E_(IS). The more facile fluctuations of E_Q for Fe^(2+) are evidence for local motions of neighboring Li^+ ions. It appears that the electron hopping frequency is lower than that of Li^+ ions. The activation energies of relaxation did not have a measurable dependence on the concentration of lithium, x

Network Models of Phage-Bacteria Coevolution

Bacteria and their bacteriophages are the most abundant, widespread and diverse groups of biological entities on the planet. In an attempt to understand how the interactions between bacteria, virulent phages and temperate phages might affect the diversity of these groups, we developed a novel stochastic network model for examining the co-evolution of these ecologies. In our approach, nodes represent whole species or strains of bacteria or phages, rather than individuals, with "speciation" and extinction modelled by duplication and removal of nodes. Phage-bacteria links represent host-parasite relationships and temperate-virulent phage links denote prophage-encoded resistance. The effect of horizontal transfer of genetic information between strains was also included in the dynamical rules. The observed networks evolved in a highly dynamic fashion but the ecosystems were prone to collapse (one or more entire groups going extinct). Diversity could be stably maintained in the model only if the probability of speciation was independent of the diversity. Such an effect could be achieved in real ecosystems if the speciation rate is primarily set by the availability of ecological niches.Comment: 8 pages, 6 figure

Isoimmunization in the human subject to the blood group factors A, B and Rh

The process by which specific antibodies are formed in an individual in response to stimulation by an antigen is called immunization. An antigen which is contained in some individuals of a species may, under suitable conditions, stimulate the production of specific antibodies when injected into other individuals of the same species who do not already possess the antigen. This process is called iso-immuhization and the antibodies produced are iso-antibodies. The first experiments on this subject were made on animals (6) by Ehrlich and Morgenroth who discovered that when one goat was iniected with the blood of another goat, immune iso-haemolysins(8)became apparent in its serum. in 1933 Irwin and Hill madeuse of the phenomenon of iso-immunization for the purpose of studying the cellular individuality of erythrocytes in doves. Back cross-hybrids were joined by parabiosis and it was found that each member of a pair of parabiotic twins developed antibodies against the erythrocytes of the other, due to mutual (3)iso-immunization. Dienst first suggested that there might be Iso-immunization within the human species. He showed that following pregnancy in some cases there was an increase in the Anti-A or anti-B iso-agglutinin titre of the mother's serum when the infant's erythrocytes contained a corresponding, A or B agglutinogen.<p

The Feminist Library: “History is Herstory, Too”

The Feminist Library is not a typical public library; it is an organization with roots in the historical revolution. Its history, services, and classification system are unique; its collection is irreplaceable. The purpose of this study is to document the history, resources, and organization of the Feminist Library in London, England

Potential Role of Some Alternative Perennial Legume Species for Low Fertility, Summer-dry Hill Country

Limitations to perennial legume persistence and growth in summer­dry hill country pastures of New Zealand may be overcome by the development of better-adapted species and cultivars. Ten alternative temperate perennial legume species were grown in a typical hill soil to evaluate herbage growth, morphology and flowering characteristics. Comparison was made with a commonly used standard white clover cultivar. Key species for further development have been identified

Elevated CO\u3csub\u3e2\u3c/sub\u3e Impacts on Grazed Pasture: Long-Term Lessons from the New Zealand FACE

A grazed pasture Free Air CO2 Enrichment (FACE) experiment has been operating for almost 15 years in the Rangitikei Region of New Zealand, following earlier work studying CO2, temperature and moisture effects on pasture in growth chambers. The longer-term results are reviewed with a focus on primary productivity, pasture compositional dynamics, nutrient cycling feedbacks and soil carbon supply. In terms of the direct effects of CO2 elevated to 475 ppm, increases in primary production were reflected in belowground allocation and legume stimulation, with the latter diminishing in the longer term and annual aboveground net herbage accumulation showing a low and variable response over time. The grazing animal has strongly influenced nitrogen (N) transformations, in terms of carbon (C) and N decoupling and return to soil, a feedback that appears to mitigate the recognized effects of increased C inputs on nitrogen limitation. Nevertheless, soil mineral N has decreased and labile fractions of soil carbon have increased – effects only detectable over a decade. Key lessons unique to this study include the animal and soil feedbacks that have driven longer-term effects differing from earlier growth chamber and the results of FACE in the first few years. Remaining questions for further investigation include mechanisms influencing legume responses and the effects of elevated CO2 on N processes (biological fixation, microbial processing, mineral N losses). The facility is currently undergoing major refurbishment in order to explore the effects of elevated CO2 and interactions with temperature and moisture availability