50,140 research outputs found
Precision Feeding in Dairy Ration Cost Minimization Under Producer's Risk Management
The biophysical simulation data from Cornell Net Carbohydrate and Protein System were used in non-linear programming model for least cost ration incorporating ingredient nutrient and price variations. Precision feeding practice indicated to have lower mean cost ration than whole herd feeding in terms of ration cost.Non-linear programming, nutrient variation, price variation, precision feeding, environmental pollution, phosphorus, nitrogen, mean cost ration, whole herd feeding, Livestock Production/Industries, Risk and Uncertainty,
Automation and control in surface irrigation systems: current status and expected future trends
Surface irrigation systems are the most popular methods for irrigating crops and pastures not only in Australia but the world over. However, these systems are often labour intensive and exhibit low water use efficiency. Rising labour costs especially in the developed world and competition for scarce water resources have generated renewed interest in the automation of surface irrigation systems.
This paper provides a comprehensive review of the current level of automation and control of surface irrigation systems. The automation techniques discussed utilise various devices including mechanical, electronic, pneumatic and hydraulic means. The use of telemetry is also discussed. With the almost universal access to high performance computers and fast internet, the concept of real-time control in surface irrigation is not far-fetched. Towards this end, an on-going research project at USQ aimed at modernising furrow irrigation by use of automatic control systems in real time is discusse
Policy framework and systems management of global climate change
Climate change is representative of a general class of environmental issues where decisions have to be taken under controversies. The policy framework for these kinds of decisions is defined by three important traits: scientific ignorance, mediatization and the need for innovation. Scientific ignorance is an issue here because decisions must be taken before the end of scientific controversies about the predictability of future climate. Mediatization is key because agents can't have a sensible experience of the global climate change, and some interest-holders (future generations, distant countries) cannot participate directly in the decision. Third, the need for innovation is crucial because today's technology offers the only alternative between fossil fuels and nuclear power as a main primary energy source.In the case of climate change, the institutional context is the United Nations Framework Convention on Climate Change. The making of global environmental policy is framed not upon a hypothetical code of international law (there is no such a thing), but upon a body of doctrine arising from consistent reference to a given set of principles. The key principles are sustainability (satisfying the need of present generations without preventing future generations to satisfy theirs), precaution (ignorance is not an excuse for inaction), the common but differentiated responsibility (developed countries take the lead in action against climate change), and economic efficiency (which lead to prefer flexible instruments over blind regulation).Given the scientific controversies and the fuzziness of guiding principles, no clear-cut demonstration could justify the choice of a theoretically optimum course of action, even in the short term. Historically, climate negotiations can be seen as an oscillation between two regulation modes. On one side is coordinated policies and measures, where countries adopt an uniform international rate of carbon tax. On the other side is emission trading, where a defined emission reduction target is allocated to each country.changement climatique; Protocole de Kyoto
Managing Water under Uncertainty and Risk: The United Nations World Water Development Report 4
This report introduces new aspects of water issues: 1) it reintroduces the 12 challenge area reports that provided the foundation for the first two World Water Development Reports (WWDR); 2) 4 new reports on water quality, groundwater, gender, and desertification, land degradation and drought; 3) in recognition that the global challenges of water can vary considerably across countries and regions, a series of 5 regional reports have been included; 4) a deeper analysis of the main external forces of freshwater resources and possibilities for their future evolution; 5) managing water under uncertainty and risk
Air Emissions of Ammonia and Methane from Livestock Operations: Valuation and Policy Options
The animal husbandry industry is a major emitter of methane, which is an important greenhouse gas. The industry is also a major emitter of ammonia, which is a precursor of fine particulate matterâarguably, the number-one environment-related public health threat facing the nation. We present an integrated process model of the engineering economics of technologies to reduce methane and ammonia emissions at dairy operations in California. Three policy options are explored: greenhouse gas offset credits for methane control, particulate matter offset credits for ammonia control, and expanded net metering policies to provide revenue for the sale of electricity generated from captured methane gas. Individually, any of these policies appears to be sufficient to provide the economic incentive for farm operators to reduce emissions. We report on initial steps to fully develop the integrated process model that will provide guidance for policymakers.methane, ammonia, carbon dioxide, greenhouse gases, climate change, offset, particulate matter, net metering, environmental policy, CAFO, manure management, biodigester, electricity, global warming, cost-benefit, incentive approach
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Net solar generation potential from urban rooftops in Los Angeles
Rooftops provide accessible locations for solar energy installations. While rooftop solar arrays can offset in-building electricity needs, they may also stress electric grid operations. Here we present an analysis of net electricity generation potential from distributed rooftop solar in Los Angeles. We integrate spatial and temporal data for property-level electricity demands, rooftop solar generation potential, and grid capacity constraints to estimate the potential for solar to meet on-site demands and supply net exports to the electric grid. In the study area with 1.2 million parcels, rooftop solar could meet 7200 Gigawatt Hours (GWh) of on-site building demands (~29% of demand). Overall potential net generation is negative, meaning buildings use more electricity than they can produce. Yet, cumulative net export potential from solar to grid circuits is 16,400 GWh. Current policies that regulate solar array interconnection to the grid result in unutilized solar power output of 1700 MW. Lower-income and at-risk communities in LA have greater potential for exporting net solar generation to the grid. This potential should be recognized through investments and policy innovations. The method demonstrates the need for considering time-dependent calculations of net solar potential and offers a template for distributed renewable energy planning in cities
Tools for Assessing Climate Impacts on Fish and Wildlife
Climate change is already affecting many fish and wildlife populations. Managing these populations requires an understanding of the nature, magnitude, and distribution of current and future climate impacts. Scientists and managers have at their disposal a wide array of models for projecting climate impacts that can be used to build such an understanding. Here, we provide a broad overview of the types of models available for forecasting the effects of climate change on key processes that affect fish and wildlife habitat (hydrology, fire, and vegetation), as well as on individual species distributions and populations. We present a framework for how climate-impacts modeling can be used to address management concerns, providing examples of model-based assessments of climate impacts on salmon populations in the Pacific Northwest, fire regimes in the boreal region of Canada, prairies and savannas in the Willamette Valley-Puget Sound Trough-Georgia Basin ecoregion, and marten Martes americana populations in the northeastern United States and southeastern Canada. We also highlight some key limitations of these models and discuss how such limitations should be managed. We conclude with a general discussion of how these models can be integrated into fish and wildlife management
Big Data and the Internet of Things
Advances in sensing and computing capabilities are making it possible to
embed increasing computing power in small devices. This has enabled the sensing
devices not just to passively capture data at very high resolution but also to
take sophisticated actions in response. Combined with advances in
communication, this is resulting in an ecosystem of highly interconnected
devices referred to as the Internet of Things - IoT. In conjunction, the
advances in machine learning have allowed building models on this ever
increasing amounts of data. Consequently, devices all the way from heavy assets
such as aircraft engines to wearables such as health monitors can all now not
only generate massive amounts of data but can draw back on aggregate analytics
to "improve" their performance over time. Big data analytics has been
identified as a key enabler for the IoT. In this chapter, we discuss various
avenues of the IoT where big data analytics either is already making a
significant impact or is on the cusp of doing so. We also discuss social
implications and areas of concern.Comment: 33 pages. draft of upcoming book chapter in Japkowicz and Stefanowski
(eds.) Big Data Analysis: New algorithms for a new society, Springer Series
on Studies in Big Data, to appea
Ensuring Urban Water Security in Water-Scarce Regions of the United States
On December 11-13, 2013, The Johnson Foundation at Wingspread, along with partner ReNUWit, convened experts from different parts of the country to discuss the implications of chronic and episodic water scarcity on our nation's water infrastructure -- with the goal of moving beyond the "case-by-case" conversation to one about how cities can transform their infrastructure and management strategies. The resulting report identifies key principles of water security and explores components of good strategy and innovative water supply options while building the case for transformation
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Challenges to the Integration of Renewable Resources at High System Penetration
Successfully integrating renewable resources into the electric grid at penetration levels to meet a 33 percent Renewables Portfolio Standard for California presents diverse technical and organizational challenges. This report characterizes these challenges by coordinating problems in time and space, balancing electric power on a range of scales from microseconds to decades and from individual homes to hundreds of miles. Crucial research needs were identified related to grid operation, standards and procedures, system design and analysis, and incentives, and public engagement in each scale of analysis. Performing this coordination on more refined scales of time and space independent of any particular technology, is defined as a âsmart grid.â âSmartâ coordination of the grid should mitigate technical difficulties associated with intermittent and distributed generation, support grid stability and reliability, and maximize benefits to California ratepayers by using the most economic technologies, design and operating approaches
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