Gregory G. Kremer

Membrane-based wet electrostatic precipitation

Abstract Emissions of fine particulate matter, PM2.5, in both primary and secondary form, are difficult to capture in typical dry electrostatic precipitators (ESPs). Wet (or water-based) ESPs are well suited for collection of acid aerosols and fine particulates because of greater corona power and virtually no re-entrainment. However, field disruptions because of spraying (misting) of water, formation of dry spots (channeling), and collector surface corrosion limit the applicability of current wet ESPs in the control of secondary PM2.5. Researchers at Ohio University have patented novel membrane collection surfaces to address these problems. Water-based cleaning in membrane collectors made of corrosion-resistant fibers is facilitated by capillary action between the fibers, maintaining an even distribution of water. This paper presents collection efficiency results of lab-scale and pilot-scale testing at First Energy’s Bruce Mansfield Plant for the membrane-based wet ESP. The data indicate that a membrane wet ESP was more effective at collecting fine particulates, acid aerosols, and oxidized mercury than the metal-plate wet ESP, even with ∼15% less collecting area.

Enhanced robust stability analysis of large hydraulic control systems via a bifurcation-based procedure

Abstract Because of their size and complexity, the initial design of many hydraulic systems is based primarily on steady state models. Nonlinear system dynamic characteristics are normally checked by simulation and/or prototype testing of the final design configuration, but even at this stage only the nominal system design and a limited number of other possible systems can be analyzed due to the excessive cost of each system analysis. Exhaustive parametric studies that verify the performance and stability of all possible systems are generally not practical. The deficiency associated with this analysis limitation is that hydraulic control systems that are predicted to be stable sometimes exhibit nonlinear pressure oscillations of unacceptably large magnitude. This paper documents the development and demonstration of a bifurcation-based analysis procedure that focuses on potential modes of oscillation rather than on analyzing all possible systems to yield a “practically rigorous” robust stability analysis of large nonlinear systems. Additional contributions of this research include: (1) proposed solutions to the main issues that complicate the robust stability analysis of large nonlinear systems, (2) demonstration of the use of the results from a bifurcation analysis to inform and enable an efficient nonlinear analysis, and (3) a detailed description of the possible nonlinear responses for a large automatic transmission hydraulic system with a 9-dimensional state space and a 24-dimensional parameter space.

A Risk Assessment Method and Safety Plan for a University Research Lab

Risk management processes follow relatively well established steps, but the hazard identification and risk assessment steps often depend heavily on “experts” with relevant expertise and operating experience. This paper presents a tool developed to help novice researchers identify and assess hazards more efficiently. The hazard identification tool was developed in the form of an updatable algorithm, based initially on previous risk assessments for similar situations as well as checklists and guidelines available from academic texts, Occupational Safety and Health Act (OSHA), and industry. Major risk categories included in the algorithm include: a) Ergonomics and Mechanical, b) Chemical, c) Physical (including Electrical Hazards, Fire Safety, Noise Hazards, and Radiation Hazards), d) Psychological and Organizational, and e) Biological. In the initial test of the algorithm, a team of non-experts used the algorithm to identify risks for two Ohio Coal Research Center (OCRC) projects dealing with solid oxide fuel cell and electrostatic precipitator testing. Their results were comparable to the list of risks generated by a group of “research experts” without the algorithm. Future plans include making the algorithm available on a wiki platform to collaboratively develop it with the combined knowledge, experience and perspectives of all participating researchers. This paper also describes the overall safety plan for the Ohio Coal Research Center (OCRC), which operates within the Institute for Sustainable Energy and the Environment (ISEE) at Ohio University. An OCRC safety flow diagram is presented that has been successfully used to improve the safety of new research projects being led by new researchers.Copyright

Engineering Around the World: Driving Local Economics in Africa With Human Power

Engineering projects are a major proponent of development in impoverished areas throughout the world. Designers face difficulties when working on projects for unfamiliar cultures and infrastructure, from problem and constraint definition to final technology transfer. Through a design project and implementation trip, this study will examine the design process as it spans borders, cultures and languages, identifying key steps and methods in the process necessary for the success of such projects. One major problem many rural communities in developing nations experience is a lack of transportation infrastructure. Forms of transport common throughout the rest of the world are, in many cases, neither economically feasible nor locally sustainable. To establish basic infrastructure, a sustainable, affordable method of transporting goods and services is essential. This research project fulfilled this need by designing an appropriate local transportation solution, a human-powered utility vehicle (HPUV). To properly understand the problem, the researcher traveled to two different rural locations in Sub-Saharan Africa (Maase-Offinso, Ghana and Meri, Cameroon) on four different trips to gather information and customer input for the design of the HPUV. A final implementation involved traveling to Meri, Cameroon for three months during which one design prototype was built, tested and reviewed by local farmers and other end-users. The vehicle was tested quantitatively against metrics and specifications derived from initial assessment trips, as well as qualitatively through customer feedback. This direct feedback provides insight into the effectiveness of the machine and the design process followed, as well as identification of possible revisions to enhance the design’s value to those who need it. The design drawings and manufacturing plan are public-domain, and local mechanics in the village were taught the basic skills needed to produce the vehicle. The drawings and manufacturing plan were also presented to a local NGO capable of producing the vehicle using local labor.Copyright

A Study of the “Optimum” Hybridization Ratio for SUVs and Heavy Trucks

In conventional vehicles the entire power is derived from the IC engine, so it is obligatory to size the engine larger than necessary for its cruising speed. The engine must be designed to account for peak power requirements like acceleration. This oversizing of the engine shifts the operating point from its efficient zone and this adversely affects the fuel economy and emissions. The idea of hybridization is that a part of the total power required can be replaced by an auxiliary power source, generally a motor powered by batteries. Hence, the IC engine can be designed for average load and can be operated with better fuel efficiency. A simulation tool called ADVISOR (Advanced Vehicular Simulator) is used for this study. The software takes the vehicle input and the drive cycle from the user, simulates the vehicle drive and gives fuel economy, acceleration performance and emissions. In this study, each of the three vehicle platforms (average SUV, full size SUV and heavy truck) is selected and a reasonable power level for that vehicle platform is taken from the data of the current conventional vehicle type. The powertrain is then hybridized by replacing part of the total power by an equivalent motor power and a set of simulations are run in ADVISOR at three different battery charge capacities to understand the effect of on-board charge. A weighted combination of performance and fuel economy results is recorded for each run, and the simulations are then repeated at a higher level of hybridization. The results for a range of “percent hybridization” levels are then evaluated to determine the optimum level. A cost optimization is also done by adding weighted factors based on cost effect of the motor, batteries, and the projected lifetime fuel costs. The penalty due to the weight of the batteries is reflected in the simulated performance and fuel economy of the vehicle, and the space effect of the batteries is also considered. The results of this thesis support the conclusion that parallel hybridization of the drive train could help SUVs and heavy trucks to improve fuel efficiency. Depending on the assumptions made for replacement battery costs and total mileage over the lifetime of the vehicle, the increased initial cost of a hybrid SUV can be justified by the operating cost savings; the benefits of hybridization are even more pronounced for heavy trucks. The “optimum” hybridization percentages are reported for each platform, with and without cost considerations.Copyright