6,927 research outputs found
EVALUATION OF PRODUCTION-WELL PERFORMANCE IN RESPONSE TO FORMATION CLOGGING AND REHABILITATION FOR THE KEWEENAW BAY TRIBAL FISH HATCHERY
Temporally, the KBIC (Keweenaw Bay Indian Community) Hatchery wells have manifested general trends of declining specific capacity and higher energy consumption due to mineral precipitation in and around the production wells. Monitoring data, laboratory water analyses, and downhole video logging have confirmed that naturally occurring minerals are precipitating and clogging the screens and, likely, the surrounding formations. The reduction in fluid pressures in and around the well-screens from active pumping wells is typical but, ultimately alters the geochemical and physical conditions such that dissolved minerals precipitate on and around the well-screens, therefore, effectively clogging the well. The clogging from mineral precipitation results in increased drawdown causing more pressure losses and clogging, and so on. Consequently, the pumps work harder and ultimately increase energy consumption and reduce production efficiencies.
The Hatchery’s SCADA system now provides the ability to monitor flows and drawdowns, which reflect important information regarding well field performance. To be more economically strategic in managing the well field operations it is apparent that the performance data from the SCADA system must be utilized to conserve well-field-related costs. The analysis of the SCADA data clearly shows that the production well’s performance diminishes with use over time due to well-screen plugging because of mineral precipitation in and around the well-screen. The observed regained performance from well rehabilitation efforts (mechanical scrubbing and/ or acid treatment) demonstrates their effectiveness, and with the use of the spreadsheet tool (developed for the KBIC Hatchery production well field), the frequency of rehabilitation efforts can be assessed on a more financially sound basis by forecasting a relative breakeven cost-benefit analysis for a particular well and associated rehabilitation. The economic analysis of power consumption and treatment costs suggests that well-treatment costs can be recovered in approximately 6-9 years based on the treatment\u27s effectiveness in offsetting the performance declination due to mineral precipitation from pumping and relative drawdown. In other words, the magnitude of the regained well performance will be proportional to the rehabilitation method’s effectiveness in removing the mineral precipitation buildup and unclogging the well screen. The SCADA system is invaluable for monitoring, understanding, and managing the well field. The continued use of the SCADA system and implementation of the other recommendations in this report will be financially beneficial as more informed flow-management decisions can be made with confidence. Furthermore, to improve life on our planet through more sustainable approaches to groundwater management, the continued development of computational tools that utilize field monitoring data in making strategic decisions for well rehabilitation and minimizing drawdown will be essential for groundwater optimization and energy cost reduction now and in the future
An investigation into gaze-based interaction techniques for people with motor impairments
The use of eye movements to interact with computers offers opportunities for people with impaired motor ability to overcome the difficulties they often face using hand-held input devices. Computer games have become a major form of entertainment, and also provide opportunities for social interaction in multi-player environments. Games are also being used increasingly in education to motivate and engage young people. It is important that young people with motor impairments are able to benefit from, and enjoy, them.
This thesis describes a program of research conducted over a 20-year period starting in the early 1990's that has investigated interaction techniques based on gaze position intended for use by people with motor impairments. The work investigates how to make standard software applications accessible by gaze, so that no particular modification to the application is needed. The work divides into 3 phases. In the first phase, ways of using gaze to interact with the graphical user interfaces of office applications were investigated, designed around the limitations of gaze interaction. Of these, overcoming the inherent inaccuracies of pointing by gaze at on-screen targets was particularly important. In the second phase, the focus shifted from office applications towards immersive games and on-line virtual worlds. Different means of using gaze position and patterns of eye movements, or gaze gestures, to issue commands were studied. Most of the testing and evaluation studies in this, like the first, used participants without motor-impairments. The third phase of the work then studied the applicability of the research findings thus far to groups of people with motor impairments, and in particular,the means of adapting the interaction techniques to individual abilities.
In summary, the research has shown that collections of specialised gaze-based interaction techniques can be built as an effective means of completing the tasks in specific types of games and how these can be adapted to the differing abilities of individuals with motor impairments
Peach and Pear Cultivar Trial
As local food production has increased in Iowa, there is renewed interest in tree fruit such as peach and pear. The purpose of this multi-year study is to compare the performance of peach and pear cultivars under soil and environmental conditions at the Horticulture Research Station, Ames, Iowa
Structural Separation versus Vertical Integration: Lessons for Telecommunications from Electricity Reforms
Structural separation between network and retail functions is increasingly being mandated in the telecommunications sector to countervail the market power of incumbent operators. Experience of separation in the electricity sector offers insights for telecommunications. Despite apparent competitive benefits the costs of contracting increase markedly when short-term focused electricity retail operations are separated from longer-term generation infrastructure investments (which require large up-front fixed and sunk cost components). The combination of mismatches in investment horizons entry barriers and risk preference and information asymmetries between generators and retailers leads to thin contract markets increased hold-up risk perverse wholesale risk management incentives and bankruptcies. Direct parallels in the telecommunications sector (e.g. separated retail and infrastructure functions) indicate exposure to similar complications intensifying many of the contractual risks arising from regulated access arrangements. In both sectors competition between vertically integrated providers appears more likely to efficiently and sustainably induce both investment and competition than separation
Long-Term Maintenance Needs Planning
This research contributes to Kentucky’s knowledge base of long-term maintenance needs in two parts. Part 1 presents an estimate of the average revenue needed to maintain four categories of highway in the first fifteen years after each is built or resurfaced. Total maintenance costs per mile for four types of facilities in five AADT volume categories were estimated. The results suggest that Kentucky is not resurfacing all its roads in a timely manner. Part II presents background information on preventive maintenance programs in the states. A review of the states found two recurring themes. The first was the widespread adoption of two types of preventive measures: thin overlays and crack sealing. The second theme was the adoption of maintenance schedules to ensure timely maintenance. The report recommends the development of a routine pavement maintenance program with three elements: (1) more timely resurfacing, (2) scheduled inspections of drainage and ditching, and (3) crack sealing. It is also recommended that the Kentucky Transportation Cabinet adopt ASSHTO’s recommended performance criteria and targets for sub-drainage assets
AVIRIS user's guide
This paper serves as a brief overview of the AVIRIS instrument (Airborne Visible/Infrared Imaging Spectrometer). The AVIRIS sensor collects data that will be used for quantitative characterization of the Earth's surface and atmosphere from geometrically coherent spectroradiometric measurements. This data can be applied to studies in the fields of oceanography, environmental science, snow hydrology, geology, volcanology, soil and land management, atmospheric and aerosol studies, agriculture, and limnology. Applications under development include the assessment and monitoring of environmental hazards such as toxic waste, oil spills, and land/air/water pollution. Mission planning and flight operations are discussed, and recommendations are given regarding the deployment of ground truth experiments
Algal culture studies related to a Closed Ecological Life Support System (CELSS)
In many respects, algae would be the ideal plant component for a biologically based controlled life support system, since they are eminently suited to the closely coupled functions of atmosphere regeneration and food production. Scenedesmus obliquus and Spirulina platensis were grown in three continuous culture apparatuses. Culture vessels their operation and relative merits are described. Both light and nitrogen utilization efficiency are examined. Long term culture issues are detailed and a discussion of a plasmid search in Spirulina is included
Travel Patterns and Expenditures of the Mature Market
Travel by persons over the age of 50 represents a key component of the leisure market. This paper examines participation in favorite activities, distance traveled, length of stay and expenditures for selected outdoor activities by this mature market based upon data from the Nationwide Recreation Survey. The paper then addresses some marketing implications suggested by these data for the development and marketing of leisure services
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