4,512 research outputs found

    User's manual for the ALS base heating prediction code, volume 2

    Get PDF
    The Advanced Launch System (ALS) Base Heating Prediction Code is based on a generalization of first principles in the prediction of plume induced base convective heating and plume radiation. It should be considered to be an approximate method for evaluating trends as a function of configuration variables because the processes being modeled are too complex to allow an accurate generalization. The convective methodology is based upon generalizing trends from four nozzle configurations, so an extension to use the code with strap-on boosters, multiple nozzle sizes, and variations in the propellants and chamber pressure histories cannot be precisely treated. The plume radiation is more amenable to precise computer prediction, but simplified assumptions are required to model the various aspects of the candidate configurations. Perhaps the most difficult area to characterize is the variation of radiation with altitude. The theory in the radiation predictions is described in more detail. This report is intended to familiarize a user with the interface operation and options, to summarize the limitations and restrictions of the code, and to provide information to assist in installing the code

    Arresting woodland bird decline in Australian agricultural landscapes: potential application of the European agri-environment model

    Get PDF
    This paper considered the applicability of the European model of land stewardship payments, in particular its support for biodiversity conservation in agricultural landscapes, to an Australian context. More broadly, the research approach described in the paper may also be applied to assessing the suitability of overseas stewardship schemes to the provision of any ecoservice in Australia, such as carbon sequestration and floodwater regulation

    Cognitive and Affective Influences on Decision-Making Strategies and Outcomes

    Get PDF
    This study examines how factors such as emotion and planning abilities, determine decision-making strategies and outcomes. Consumer-based decision tasks are one way for researchers to measure the decision-making process and outcomes of individuals, while bringing an element of reality to the task through the utilization of decisions about everyday items that someone might purchase (e.g., a car, apartment, etc.). Using these types of tasks, researchers can measure the quality of a decision (e.g., did the participant come up with the best solution?), as well as the decision or search strategy. Previous research shows that cognitive factors are important when individuals make decisions (Engle, 2018). Emotional components are also important to consider when addressing decision making in adulthood. Older adults have a better memory for emotion-laden content compared to younger adults (Yoon et al., 2009). Older adults also tend to display a bias toward positive information when making decisions (Carstensen et al., 1999). The current study uses emotional variables such as decision importance and task difficulty, as well as measures of cognitive functioning, such as the digit symbol substitution task, to predict decision making quality and strategies in a consumer-based task. While previous research shows that cognitive abilities (Engle, 2018; Patrick et al., 2013) and affective components (Carstensen et al., 1999) are both important for predicting decision-making outcomes, the research regarding affective components is less well established. Results found that those who relied on a particular search strategy were more than twice as likely (OR = 2.34) to be classified as making a good decision in choosing a home. Results from this study have implications for alternate routes of intervention in the decision-making process

    A rural agricultural-sustainable energy community model and its application to Felton Valley, Australia

    Get PDF
    Energy and food security require a delicate balance which should not threaten or undermine community prosperity. Where it is proposed to derive energy from conventional fossil fuel resources (such as coal, shale oil, natural gas, coal seam gas) located in established rural areas, and particularly where these areas are used for productive agricultural purposes, there are often both intense community concern as well as broader questions regarding the relative social, economic and environmental costs and benefits of different land uses and, increasingly, different energy sources. The advent of mainstream renewable energy technologies means that alternative energy options may provide a viable alternative, allowing energy demand to be met without compromising existing land uses. We demonstrate how such a Sustainable Energy Rural Model can be designed to achieve a balance between the competing social goals of energy supply, agricultural production, environmental integrity and social well-being, and apply it to the Felton Valley, a highly productive and resilient farming community in eastern Australia. Research into available wind and solar resources found that Felton Valley has a number of attributes that indicate its suitability for the development of an integrated renewable energy precinct which would complement, rather than displace, existing agricultural enterprises. Modelling results suggest a potential combined annual renewable energy output from integrated wind and solar resources of 1,287 GWh/yr from peak installed capacity of 713 MW, sufficient to supply the electrical energy needs of about 160,000 homes, in combination with total biomass food production of 31,000 tonnes per annum or 146 GWh/yr of human food energy. The portfolio of renewable energy options will not only provide energy source diversity but also ensures long-term food security and regional stability. The Felton Valley model provides an example of community-led energy transformation and has potential as a pilot project for the development of smart distributed grids that would negate the need for further expansion of coal mining and coal fired power stations

    The Health and Well-Being of Young Children of Immigrants

    Get PDF
    Provides an overview of immigration trends and their effects on the composition of the young child population. Looks at poverty, family structure, parental work patterns, immigrant parents' education, health status, and health insurance coverage

    Improving the Impact of Market Reform on Agricultural Productivity in Africa: How Institutional Design Makes a Difference

    Get PDF
    Improving the Impact of Market Reform on Agricultural Productivity in Africa: How Institutional Design Makes a Difference Abstract: This paper reviews the emerging empirical record of agricultural marketing policy reform and agricultural productivity, drawing from research on food access and agricultural productivity supported by USAID’s Africa Bureau on seven countries in West, Eastern, and Southern Africa. We also examine key factors constraining past and future performance of the food systems in these countries. The paper concludes by identifying a set of policy issues for further consideration that would help provide the investment incentives to promote productivity growth for the millions of low-input semi-subsistence rural households in the region.food security, food policy, market reform, Agricultural and Food Policy, Marketing, Productivity Analysis, Downloads June 2008 - July 2009: 40, Q13,

    On the Measurement of “Grayness” of Cities

    Get PDF
    We consider a situation where individuals belonging to multiple groups inhabit a space that can be divided into smaller distinguishable units, a feature characterizing many cities in the world. When data on an economic attribute (in our case, income) is available, we conceptualize a phenomenon that we refer to as “Grayness” - a combination of spatial integration based upon group-identity and income. Grayness is high when cities display a high degree of spatial co-existence in terms of both identity and income. We lay down some desirable properties of a measure of Grayness and develop a simple and intuitive index that satisfies them. We provide an illustration by using data from the Indian city of Hyderabad, and selected American cities

    Analysis of existing mathematics textbooks for use in secondary schools.

    Full text link
    Thesis (Ed.M.)--Boston University Thesis (M.A.)--Boston Universit

    Statistical Analysis of Small Ellerman Bomb Events

    Full text link
    The properties of Ellerman bombs (EBs), small-scale brightenings in the H-alpha line wings, have proved difficult to establish due to their size being close to the spatial resolution of even the most advanced telescopes. Here, we aim to infer the size and lifetime of EBs using high-resolution data of an emerging active region collected using the Interferometric BIdimensional Spectrometer (IBIS) and Rapid Oscillations of the Solar Atmosphere (ROSA) instruments as well as the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). We develop an algorithm to track EBs through their evolution, finding that EBs can often be much smaller (around 0.3") and shorter lived (less than 1 minute) than previous estimates. A correlation between G-band magnetic bright points and EBs is also found. Combining SDO/HMI and G-band data gives a good proxy of the polarity for the vertical magnetic field. It is found that EBs often occur both over regions of opposite polarity flux and strong unipolar fields, possibly hinting at magnetic reconnection as a driver of these events.The energetics of EB events is found to follow a power-law distribution in the range of "nano-flare" (10^{22-25} ergs).Comment: 19 pages. 7 Figure
    • …
    corecore