• Energy Research
• US close
• GB close
• NL close
• RU close
• English close

With an increased demand for renewable energy production, especially the conversion of biomass to biofuels, perennial grasses are gaining interest as a renewable source of biofuel feedstocks. Identifying the trade-offs between bioenergy crop cultivation and nutrient runoff, erosion, and water requirements will be important as the demand for these crops continues to grow. The primary objective of this study is develop an integrated optimal control model that estimates the potential effects on water quality and demand and soil erosion from cultivating switchgrass and other perennial grasses instead of conventional crops at the watershed scale. The Soil and Water Assessment Tool is used to model these land use changes. In this research, we developed an optimization method based on genetic algorithms to evaluate different land cover change scenarios and their effect at the watershed level by coupling the SWAT model with a multi-objective genetic algorithm, that takes into consideration the minimization of nutrient loading, sediment yield due to erosion at the watershed outlet, the effects on regional water resources, while maximizing biomass production. The optimal control model will help further the understanding of the environmental impacts of cultivating biofuel feedstocks and is intended to aid policy makers and stakeholders when making decisions to increase feedstock production.

Writen for practitioner audience ; Provides practitioner-friendly advice on how to develop a makerspace plan and learning activities that are sustainable even with low budgets. ; This project was made possible in part by the Institute of Museum and Library Services RE-05-15-0021-15. ; http://deepblue.lib.umich.edu/bitstream/2027.42/117499/1/tl-sustaining-makerspace.pdf ; Description of tl-sustaining-makerspace.pdf : Main article

Catalytic conversion of biomass-derived oxygenates to fuels and value-added chemicals is a promising strategy in the search for renewable and sustainable energy sources. Most relevant catalytic processes are carried out in an aqueous environment using supported transition metal catalysts. The reaction network consists of multiple series and parallel pathways leading to formation of hydrogen, alkanes, and lighter oxygenates. The final product distribution ultimately depends on the sequence and competition of C−C, C−O, C−H, and O−H bonds scissions. Ethylene glycol (EG) is the simplest model molecule of various biomass-derived polyols that has a C:O stoichiometry of 1:1 and contains all relevant C−C, C−O, C−H, and O−H bonds. While the reaction mechanism of EG reforming is to some degree understood at the metal–gas interface, lack of a well-established methodology for describing the influence of a complex liquid phase on a reaction across a solid–liquid interface has hindered similar theoretical studies in an aqueous environment. In this dissertation, we show how first-principles calculations can be used for a systematic investigation of complex reaction pathways at a metal–water interface. We proposed a multistep strategy where the description of the influence of an aqueous environment on reaction kinetics and equilibria is successively refined. First, we developed a new computational approach for implicit solvation of periodic metal slabs by integrating planewave density functional theory (DFT) calculations with an implicit solvation model. Rapid convergence with size of the metal cluster and basis set was demonstrated for C−C cleavage in dehydrogenated EG at a Pt (111)/H2O interface. The method was then successfully applied for predicting experimentally reported CO frequency shifts in water at Pt (111)/H2O and Pd (111)/H2O interfaces. Next, we developed a hybrid quantum mechanics/molecular mechanics (QM/MM) method to allow an explicit description of water molecules at the metal–water interface, and applied it to ...

As natural resources are decreasing and environmental pollution is increasing, the buildings that play an important role in this problem should be constructed sustainably so their affects are kept to a minimum. Hospitals operate 24 hours a day and 7 days a week, therefore they are one of the largest energy consumers. Hence designers have started to design healthcare facilities according to the Leadership in Energy and Environmental Design (LEED) criteria, believing that it will reduce waste production, energy consumption and increase patient satisfaction by creating brighter and less stressful facilities. To understand if the claims are correct or not, this thesis first studied the results of the patient survey, Hospital Consumer Assessment of Healthcare Providers and System (HCAHPS), undertaken at most of the hospitals in the U.S., and compares the results to LEED and non-LEED certified hospitals. To find answers for the claims related to the financial benefits, this thesis compared three financial indicators; cost of operation of plant, profitability, and inpatient revenue. In the cases where there is a large enough sample size, a t-test is used to compare two groups, however when the sample size was not large enough, two groups are compared based on their means. For the cost of operation of plant and profitability, non-LEED certified hospitals are performing better. However, the patient satisfaction and inpatient revenues are significantly higher at the LEED-certified hospitals.

Leadership in small and medium enterprises (SMEs) has remained an under-researched area in the management literature, especially in developing countries such as Nigeria. SME owner-managers in Nigeria lacked in-depth understanding of their leadership style to objectively evaluate its implication on long-term performance and growth of their enterprise. The purpose of this qualitative multiple-case study was to explore the experiences of SME owner-managers in Nigeria to gain an in-depth understanding of their leadership style and its implication for long-term performance and growth of their enterprise. The conceptual framework for this study was anchored in two key concepts; leadership styles and leadership in SMEs, with the full range leadership model as the theoretical foundation. The research question sought to explore the role of SMEs owners and managers leadership styles in the long-term success of their enterprise. Interview data were collected from 6 SME owner-managers who employ less than 200 employees within the manufacturing, education, and trading sectors. The cross-case synthesis technique was used for data analysis which allowed for within-case analysis and cross-case comparisons. Findings from this study showed that Nigerian SME owner-managers do not follow any specific leadership style. They exhibited few characteristics of transformational and transactional leadership behaviors, leaning more to transactional leadership. This study has significance for positive social change by providing insights on how leadership styles can improve the performance and sustainability of Nigerian SMEs, thus increasing their capacity to create employment.

One of the major problems with using renewable energy is the mismatch between power generation and demand as renewable energy generation and energy usage from HVAC equipment depend on unsynchronized natural factors. To reduce this supply-demand mismatch many researchers suggested using thermal energy storage to shift cooling and/or heating loads. A thermal energy storage (TES) tank can be integrated with building heating and cooling systems using several methods described in the open literature. This thesis explores a novel method to integrate water-based TES with an indoor air coil using a three fluid heat exchanger (TriCoil(TM)). The three fluid heat exchanger will thermally connect water from the TES, refrigerant from the outdoor unit, and indoor air. A test setup has been developed inside the Psychrometric Coil Testing Facility of Oklahoma State University (OSU) to test the TriCoil(TM). The heat balance of the test setup for different operation modes and test points was within +/-5%. An uncertainty analysis has been performed on the test results and major sources of uncertainties have been identified. In the experiment done for this thesis, water from the TES was successfully charged up to 15 kW (cooling) with a log mean temperature difference (LMTD) of 18.5 K using a 4-ton capacity outdoor unit. TriCoil(TM) was also used to discharge the water from TES with a max capacity of 11.5 kW (heating) with an LMTD of 8.7 K, a water flow rate of 1700 kg/h, and an airflow rate of 1600 CFM.

A single dose of additive contributes to three consecutive fine coal unit operations, i.e., flotation, dewatering and reconstitution, whereby the fine coal is first combined with water in a predetermined proportion so as to formulate a slurry. The slurry is then mixed with a heavy hydrocarbon-based emulsion in a second predetermined proportion and at a first predetermined mixing speed and for a predetermined period of time. The conditioned slurry is then cleaned by a froth flotation method to form a clean coal froth and then the froth is dewatered by vacuum filtration or a centrifugation process to form reconstituted products that are dried to dust-less clumps prior to combustion.

"The microwave wireless power transfer system can be divided into five elements, including energy emission component, energy harvesting module, energy storage component, power conditioning component and functioning module. This dissertation is dedicated to developing a new class of microwave wireless power transfer system by investigating the first three elements. To increase the energy harvesting efficiency, the metamaterial absorber based energy harvesting device was introduced. The investigation to this new device started with a transmission line model to characterize the metamaterial absorber and followed by demonstration in both simulation and experiment for the energy harvesting based on metamaterial absorber with varies of substrate materials. Both simulation and experimental results are qualitatively consistent with the transmission line model prediction that the signal transfer ratio reduces when the dielectric loss of the substrate increases. The highest experientially demonstrate signal transfer ratio reaches 96% when using Rogers 5880LZ as the substrate material. In order to increase the transmission efficiency between the emission component and energy harvesting module, it is desired to identify the incident wave direction from the energy harvesting perspective and enhance the antenna gain from both emission and energy harvesting perspectives. To identify the incident wave direction, we have adapted the basic design of metamaterial absorber to fabricate a microwave subwavelength imaging device. Similar to an optical camera, such device is able to track the incident wave direction when combining with a microwave lens. The performance test of the imaging device based on metamaterial absorber has shown that it can not only identify the position of the focused beam with an accuracy of 1% wavelength in the far field imaging test, but also is capable of carrying out near field imaging by capturing the electromagnetic power distribution with ignorable distortion to the original power distribution. The gain enhancement was proposed by placing a artificial magnetic conductor (AMC) underneath the radiation antenna. AMC is able to reflect the microwave with a phase shift of between -90 and 90 degree in a frequency band, call in-phase reflection band. We have built a transmission line model for AMC. Derivation based on this transmission line model reveals that the in-phase reflection bandwidth has a theoretical limit as a function of the thickness and permeability of AMC substrate. The method of making the in-phase reflection bandwidth of an AMC sample approaching its theoretical limit has been proposed. Experimentally, a ratio to the theoretical limit of 98.5% has been achieved, which is the highest compared to a number of reported values in AMC simulation and experiment results. By comparing out proposed method to two previously reported methods, we found that our proposed method gives more restricted value. Finally, work has been carried out to develop a new class of energy storage component for the microwave wireless transfer system. A Fe-Ni based electrochemical negative electrodes has been experimentally demonstrated by sintering chemically prepared Fe–Ni nanoparticles into a nanoporous pellet with thickness of 65 μm and mass loading density of 20 mg/cm-2. This electrode is consisted of nanoscale mixture of an Fe-rich body-centered cubic Fe(Ni) phase and a Ni-rich face-centered cubic Fe–Ni phase. The high conductive and structure stability is provided by the Ni-rich phase and the electrochemically active component of the electrodes is produced by the selective conversion of the Fe-rich phase to hydroxides. The experimental measurement shows the compositionally optimized electrodes exhibit a specific capacitance in excess of 350 F/g by normalizing to the whole electrode mass and retain more than 85% of their maximum specific capacitance after 2000 charging/discharging cycles. This desirable combination of physical and electrochemical properties indicates that such electrodes may be useful as the negative electrode in high performance asymmetric supercapacitors."

Global endeavors to reduce emissions in the shipping industry are accelerating the interest in fuel cell systems. This paper explores the application of different fuel cell types (LT-PEMFC, HT-PEMFC and SOFC) in combination with different fuels (LH2, LNG,MeOH and NH3) in expedition cruise ships. An impact model is developed for the first design phase. The goal of this paper is to evaluate the impact of the combination of fuel cell system implementation and operational profile on expedition cruise vessels. Impact is expressed in ship size, capital cost, operational cost and emissions. The model takes into account: fuel storage, on-board fuel processing, fuel cell system characteristics, balance of plant components, fuel cost over operational lifetime and all onboard emissions. In the research, seven different fuel cell systems and three different hybridization strategies are considered. For the six best performing combinations of fuel cell system and hybridization strategy, the range, endurance and capacity requirements are systematically varied to determine whether the best performing option depends on these requirements. Finally, hybrid option 2 (using diesel generators to support during long transits) combined with a methanol fueled LT-PEMFC system results in the lowest newbuild price. This option does comply with emission regulations and CO2 goals for 2030. Hybrid option 2 combined with an LNG fueled LT-PEMFC system results in the lowest total cost (newbuild price and fuel cost). This option does comply with emission regulations, but does not meet CO2 goals for 2030. When it is desired to reach this CO2 target, hybrid option 2 with methanol fueled LT-PEMFC is also recommended from a total cost perspective. ; Marine Technology

Analyzed wind resource characteristics at elevated heights (50 m-200+m) incuding shear and turbulence profiles for some areas of the Great Lakes and M idwest sites.