CCD QE in the Soft X-ray Range

e2v has previously provided back-illuminated CCDs for several solar observation projects, resulting in a number of key articles on CCD QE in the soft X-ray region. To update these, e2v has arranged for tests on X-ray optimised EMCCDs at a synchrotron. These have shown QE of at least 45% from 40 eV to 2000 eV, with Enhanced process devices having significantly higher QE than Basic process. The measured values were similar to data published from the SDO SXI mission, showing that the e2v process has been stable over many years. The soft X-ray QE measurements show a reasonable fit to the simple layer model for energies > 600 eV. For energies < 100 eV, measurements show slightly lower QE than the model prediction for both Basic and Enhanced processes. For energies 100 eV to 600 eV, measurements show a reasonable fit to the model for the Basic process, but less improvement from the Enhanced process than the model predicts. Comparing the ~80% typical QE for UV-optimised CCDs at 385 nm with the 45% QE measured at 120 eV in this study, there is a discrepancy in QE for two photon energies with the same absorption length measured on CCDs from the same back-thinning process (one type with AR coating, one type without)

Investment Analysis of Alternative Dairy Systems under MILC

Three dairy systems, 120-cow grazing, 120-cow conventional, and 600-cow concentrated, were evaluated by internal rate of return (IRR) accounting for the Milk Income Loss Contract (MILC). With MILC, the grazing and conventional systems had higher IRRs. Without MILC, the 600-cow dairy had the highest IRR. Results were sensitive to assumptions.Concentrated feeding, conventional, grazing, internal rate of return, Livestock Production/Industries,

Using Total Solids Concentration to Estimate Nutrient Content of Feedlot Runoff Effluent from Solid Settling Basins, Vegetative Infiltration Basins, and Vegetative Treatment Areas

Increased environmental awareness has promoted the need for improved feedlot runoff control. The use of vegetative treatment systems (VTSs) to control and treat feedlot runoff may enhance environmental security and protect water quality. Knowledge of effluent nutrient concentrations throughout the vegetative treatment system is required to evaluate impact on water quality and system performance. Previously collected VTS monitoring data has provided the opportunity to investigate relationships between effluent quality parameters. The objective of this study was to evaluate, through correlation and regression, the relationships between total solids, nutrients, and effluent quality indicator concentrations of feedlot runoff at various stages of treatment in a VTS, including solid settling basin, vegetative infiltration basin, and vegetative treatment area effluent. Results of a correlation and primary factor analysis showed that most of the parameters’ concentrations were strongly correlated to each other, with a single factor capable of describing more than 60% of the variability of monitored parameters. Regression equations were developed to relate nutrient content and effluent quality indicator concentrations to total solids concentrations. Results were satisfactory for most parameters, indicating that total solids concentrations provided significant insight into VTS performance relative to nutrient concentration and effluent quality indicators. A comparison between predicted, based on total solids content, and monitored mass release of the parameters was conducted. No statistical difference was found for most parameters; indicating that effluent volume release along with total solids concentrations can be used to provide an estimate of nutrient mass in solid settling basin, vegetative infiltration basin, and vegetative treatment area effluent

Comparison of Construction Costs for Vegetated Treatment Systems in the Midwest

Vegetated treatment systems (VTSs) provide an alternative to containment basin systems for beef feedlot runoff control. Beef producers in the Midwestern United States have shown an increasing interest in using VTSs as a perceived lower cost option to containment basin systems. This paper reports the actual construction costs associated with 21 VTSs (eight on permitted Concentrated Animal Feeding Operations (CAFOs) and 13 on non permitted Animal Feeding Operations (AFOs)) located within Iowa, Minnesota, South Dakota, and Nebraska. The VTS construction costs are reported on a per head basis in 2009 adjusted dollars for each system. Cost comparisons are presented between CAFO and AFO facilities, by location and by system type. Additionally, estimated construction cost comparisons between open feedlots with VTS systems, open feedlots with containment basins, monoslope barns and hoop structure beef production systems are provided. Results from the cost comparison indicate that monoslope barns with concrete floors are the highest cost at $621 per head on average followed by hoop structures at$395 per head. Vegetated Treatment Systems designed for CAFO facilities ($77 per head avg.) are less expensive to construct than a traditional containment basin ($129 per head avg.) The same results indicated that an AFO VTS ($62 per head avg.) was less expensive to build than a containment basin on a similar facility ($195 per head). The data indicated that the least expensive VTS for an AFO is a sloped or sloped and level VTA ($42 per head avg.) followed by a pump sloped VTA ($68 per head avg.) and a sprinkler VTS ($87 per head avg.)

Vegetated Treatment System Models: Modeled vs. Measured Performance

Vegetated treatment systems (VTS) are designed to control runoff from beef feedlots. A VTS consists of a solids settling basin followed by either a vegetated treatment area (VTA) or a vegetated infiltration basin (VIB) followed by a VTA. Two computer models were developed at Iowa State University (ISU) to simulate traditional containment, a VTS with a settling basin and a VTA, and a VTS with a settling basin, VIB, and VTA. The models predict runoff volume and nutrient mass entering and leaving the system for a given design and specific weather conditions. In this paper, the monitored performance of four feedlot VTSs in Iowa is compared to the performance predicted by each site model run. These sites are undergoing extensive monitoring to determine the mass of nutrients discharged from each system component. Weather data including maximum temperature, minimum temperature and precipitation are also continuously recorded. System component discharge data collected at each site is compared to data generated by the model using site specific weather data for model calibration purposes. Comparisons of modeled versus monitored system performance indicate that the VTS models currently under predict discharge from the VTAs at all four sites. The VTS models also under predicted the VIB performance for both of the VIB sites. While the measured and monitored flow volumes from the SSB matched relatively well, the nutrient concentration released from the SSB was much higher than the concentration predicted by the VTS models

Performance of Six Vegetative Treatment Systems for Controlling Runoff from Open Beef Feedlots in Iowa

Beef feedlots of all sizes are looking for more cost-effective solutions for managing feedlot runoff. Vegetative treatment systems (VTSs) are one potential option that has been proposed. Iowa State University (ISU) has monitored the performance of six VTSs on open beef feedlots throughout Iowa since 2006. These feedlots have interim, National Pollution Discharge Elimination System (NPDES) permits that allow the use of VTSs to control and treat feedlot runoff. As part of the permit requirements for these feedlots the effluent volumes, nutrient concentrations, and nutrient masses exiting each component of the VTS were monitored. This paper describes the VTSs and monitoring methods used in this study and evaluates the effectiveness, in terms of both effluent concentration and nutrient mass transport reductions, of each system. During the three-year monitoring period, results have shown that VTSs are capable of reducing the nutrient mass exiting the VTSs by 65 – 99% as compared to a settling basin only system, with performance varying by both site and year. In addition to overall mass transport reductions, nutrient concentrations were also reduced, typically reduced by 50-90%, during treatment. Furthermore, monitoring results have shown a consistent improvement in system performance during the three years of the study. Much of this improvement can be attributed to improved management techniques and system modifications that addressed key performance issues

Evaluation of Vegetative Treatment System Performance of CAFO Beef Feedlot Runoff Control

Rules released by EPA in 2003 require beef feedlots defined as Concentrated Animal Feeding Operations (CAFO) to control rainfall runoff from their feedlots. The rules included verbiage that allowed for the design and use of “Alternative Technologies” and require that any “Alternative Technology” be modeled to show they are at the least as effective as traditional storage systems. The objective of this project is to evaluate, through field monitoring, the performance of vegetative treatment systems (VTSs). Six Iowa beef feedlots are being monitored, and through additional funding and partnering organizations, four other sites are being monitored in Nebraska, Minnesota, and South Dakota. Results from the Iowa sites thus far have shown nutrient mass release reductions 40 – 99% as compared to a settling basin only system