504,544 research outputs found

    Crystal growing by electrodeposition from dense gaseous solutions

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    Single crystals and dendritic formations of silver are grown on platinum electrodes by electrodeposition from a dense gaseous solution of silver nitrate in ammonia. Process is modification of hydrothermal process, and also differs from standard electrodeposition by permitting single crystals to be grown from hydrogen-bonded solvents

    ISER 2012 Working Paper No. 1

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    Large resource development projects take years to plan. During that planning time, the public frequently debates the potential benefits and risks of a project, but with incomplete information. In these debates, some people might assert that a project would have great benefits, while others might assert that it would certainly harm the environment. At the same time, the developer will be assessing different designs, before finally submitting one to the government permitting agencies for evaluation and public scrutiny. For large mines in Alaska, the government permitting process takes years, and often includes an ecological risk assessment. This assessment is a data-intensive, scientific evaluation of the project’s potential ecological risks, based on the specific details of the project. Recently, some organizations have tried to bring scientific rigor to the pre-design public discussions, especially for mining projects, through a pre-design risk ecological risk assessment. This is a scientific assessment of the environmental risks a project might pose, before the details of project design, risk-prevention, and risk-mitigation measures are known. It is important to know whether pre-design risk assessment is a viable method for drawing conclusions about risks of projects. If valid risk predictions can be made at that stage, then people or governments would not have to wait for either a design or for the detailed evaluation that is done during the permitting process. Such an approach could be used to short cut permitting. It could affect project financing; it could affect the schedule, priority, or even the resources that governments put toward evaluating a project. But perhaps most important: in an age where public perceptions are an important influence on a project’s viability and government permitting decisions, a realistic risk assessment can be used to focus public attention on the facts. But if the methodology is flawed and results in poor quality information and unsupportable conclusions, then a pre-design risk assessment could unjustifiably either inflame or calm the public, depending on what it predicts.Executive Summary / Section 1. Introduction / Section 2. Overview of Ecological Risk / Section 3. Ecological Risk Assessment Methodology / Section 4. Examples of Post-Design Ecological Risk Assessments / Section 5. Pre-Design Ecological Risk Assessment: Risks of Large Scale Mining in the Bristol Bay Watershed / Section 6. Conclusion / Bibliograph

    Stimulated Raman Adiabatic Passage via bright state in Lambda medium of unequal oscillator strengths

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    We consider the population transfer process in a Lambda-type atomic medium of unequal oscillator strengths by stimulated Raman adiabatic passage via bright-state (b-STIRAP) taking into account propagation effects. Using both analytic and numerical methods we show that the population transfer efficiency is sensitive to the ratio q_p/q_s of the transition oscillator strengths. We find that the case q_p>q_s is more detrimental for population transfer process as compared to the case where qpqsq_p \leq q_s. For this case it is possible to increase medium dimensions while permitting efficient population transfer. A criterion determining the interaction adiabaticity in the course of propagation process is found. We also show that the mixing parameter characterizing the population transfer propagates superluminally

    The Climate for Business Development and Employment Growth in Puerto Rico

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    Employment rates in Puerto Rico range from 55 to 65 percent of U.S. rates during the past thirty years. This huge employment shortfall holds for men and women, cuts across all education groups, and is deeper for persons without a college degree. The shortfall is concentrated in the private sector, especially labor-intensive industries that rely heavily on less educated workers. Motivated by these facts, we identify several factors that undermine employment growth and business development, including high minimum wage requirements, a history of tax incentives for capital-intensive activities, a host of regulatory entry barriers, and a business climate in which profitability and survival too often rest on the ability to secure favors from the government,. We pay close attention to the permitting process whereby the government oversees and regulates construction and real estate development projects, the commercial use of equipment and facilities, and the periodic renewal of various business licenses. Based on interviews with experts and participants in the permitting process, and supplemented by other sources, we compile evidence that the permitting process is excessively slow and costly, fraught with uncertainty, subject to capricious outcomes, susceptible to corruption, and prone to manipulation by business rivals and special interest groups.

    Wave Energy: a Pacific Perspective

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    This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by The Royal Society and can be found at: http://rsta.royalsocietypublishing.org/.This paper illustrates the status of wave energy development in Pacific Rim countries by characterizing the available resource and introducing the region‟s current and potential future leaders in wave energy converter development. It also describes the existing licensing and permitting process as well as potential environmental concerns. Capabilities of Pacific Ocean testing facilities are described in addition to the region‟s vision of the future of wave energy

    A Deterministic Analysis of Decimation for Sigma-Delta Quantization of Bandlimited Functions

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    We study Sigma-Delta (ΣΔ\Sigma\Delta) quantization of oversampled bandlimited functions. We prove that digitally integrating blocks of bits and then down-sampling, a process known as decimation, can efficiently encode the associated ΣΔ\Sigma\Delta bit-stream. It allows a large reduction in the bit-rate while still permitting good approximation of the underlying bandlimited function via an appropriate reconstruction kernel. Specifically, in the case of stable rrth order ΣΔ\Sigma\Delta schemes we show that the reconstruction error decays exponentially in the bit-rate. For example, this result applies to the 1-bit, greedy, first-order ΣΔ\Sigma\Delta scheme
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