Dynamic Optimization of Nitrogen Use in Agriculture

Agricultural production is highly dependent on inorganic substances including fertilizers. High-yielding crop varieties, such as corn, require large amounts of primary nutrients including nitrogen, phosphorus and potassium. Farmers often add a surplus of nutrients to crops to maximize yields. Utilization of primary nutrients has increased by more than 300% while that of nitrogen alone has increased by more than 600% between 1960 and 2007 (USDA, 2009). From 1964 to 2007, the use of nitrogen in the corn sector alone increased from 1,623,000 to 5,714,000 nutrient tons (USDA, 2009). While increasing production, increased fertilizer use can potentially create negative externalities in the form of nitrate-nitrogen contamination in groundwater. Groundwater is the source of drinking water for about half the total U.S. population and nearly all of the rural population, and it provides over 50 billion gallons per day for agricultural needs (USGS, 2009). In the U.S. the main source of nitrate pollution in the groundwater results from the actions of farmers through the use of fertilizers and other chemicals (Haller, et al. 2009). Nitrogen-nitrate contamination can have adverse human affects including methemoglobinemia or ―blue-baby‖ syndrome (Majumdar, 2003). The potential for nitrate contamination in corn production is especially problematic as corn alone accounts for over 90% of feed grains produced in the U.S. (USDA, 2009). The USDA estimates that approximately 80 million acres of land is planted to corn, with the majority in the Heartland region (the Midwest) of the U.S. (2009). The Heartland region is primarily rural and much of the population there derives its drinking water from groundwater. Therefore, the potential for groundwater contamination is greatly increased in this region.Environmental Economics, Nitrogen/Nitrate Contamination, Dynamic Optimization, Agriculture, Agricultural and Food Policy, Demand and Price Analysis, Environmental Economics and Policy, C61, C63, Q10, Q51, Q53,

Regional differences in technology : theory and empirics

The aim of this paper is, on the one hand, to give a review of several streams in the litera-ture which differ with respect to the extent they assume knowledge to spread over regions. On the other hand, this paper shows the extent to which these theories are supported empirically. The regional neoclassical growth model focuses on the immediate diffusion of technological knowledge. Alternative theories like cumulative causation and imperfect diffusion theories focus on the issue that technology gaps between regions will persist over time. Cumulative causation assumes that there exists no diffusion of knowledge, while imperfect diffusion theories assume that diffusion will take place, though slowly. These theoretical insights lead to several testable hypotheses on the presence and the development over time of regional technology gaps. This paper attempts to use a new set of data on R&D in the European Union to explore this field. Evidence from regional R&D statistics will be used to highlight differences in technological activity between the regions within the leading European economies. Also the factors that are proposedly related to the relative technological activity of a region are analysed, in addition to the long term implications of technology gaps.research and development ;

Green Up Pavement Rehabilitation Design Tool

While designers produce pavement rehabilitation recommendations every day, for projects of all sizes, most designers have little information on the environmental impact of their recommendations. This research developed a new decision tool, called the “Green Up Pavement Rehabilitation Design Tool,” to allow the comparison of different rehabilitation solutions in terms of greenhouse gas emissions and to encourage sustainable practices such as materials recycling and the use of permeable, cool, and quiet pavement surfaces. The project aligns with the major goal of California Senate Bill 1, which is “to address deferred maintenance on the state highway system and the local street and road system,” by providing a rehabilitation strategy selection tool as well as an educational tool to promote sustainable pavement practices. The Green Up graphic and the overall methodology were finalized in consultation with representatives of the portland cement concrete and asphalt industries in California. For designers interested in learning more, the tool includes fact sheets about sustainable pavement rehabilitation strategies and links to additional online resources

Analysis of chemical constitutents and additives in hydraulic fracturing waters 1. Technical review and proposal for a non-target approach

This technical report is a first one of series of reports addressing the issue of chemical constituents and additives occurring in the waters related to hydraulic fracturing in the exploitation of unconventional hydrocarbons. Specific focus is on the types of chemical constituents being addressed so far in flowaback, produced waters and potentially exposed ground and surface water. It gives on overview on typical approaches. With regard to organic constituents it addresses the typically examined compounds and investigates to which extent non-targeted approaches with accurate mass spectrometry can be used to fill existing knowledge gaps. The concept of an envisaged feasibility study for a imoproved baseline assessment is described, too.JRC.D.2-Water and Marine Resource

Rheology and Settling Dynamics of a Particle Filled Aqueous Polymer Gel for Hydraulic Fracturing Fluid Systems

Outstanding Undergraduate Award for Research Excellence 2013Outstanding Undergraduate Award for Research Excellence 2015Hydraulic fracturing, more commonly known as fracking, is a hydrocarbon capturing method that uses a high pressure fluid to fracture layers of shale, which then releases the hydrocarbons which flow to the surface for capture. In order to keep the fractures open, special sands called proppants are carried in with the fracking fluid. This functions by keeping the fracture open, while allowing natural gas to flow through the fracture. Hydroxypropyl Guar (HPG) is a high molecular weight, water soluble polymer used in the food industry as a viscosifier of water based foods, and in the petroleum industry as an additive in hydraulic fracturing fluids. The fracking fluid is further modified via addition of a cross linker, which causes the fluid to become a gel, making it extremely viscous. Once the proppant is suspended in the fracture, a breaker is added to the solution which allows the fluid to flow again, while retaining the structure of the fracture. Unfortunately, some of the current fluid components used in industry are hazardous and present health risks upon unanticipated exposure. This research aims to maintain, or surpass, current fluid standards by developing potential substitutes for the presently used components. To do this, a full factorial experimental design has been conducted with cross linker concentration and chopped nylon fiber concentration as exploratory variables. It is observed that the addition of the chopped fibers significantly decreases the settling velocity of suspended proppant particles, while not significantly affecting the fluid viscosity, thus allowing for a decrease in the toxic cross linker concentration for a given required settling velocity. Further, with rheological information, theoretical models will be developed for predicting settling velocities in a hypothetical fluid system.Ohio State College of EngineeringNo embargoAcademic Major: Chemical Engineerin