College of Engineering Technical Reports

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Now showing 1 - 10 of 19
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    Plasma Arc Gasification Application to the City and County of Honolulu, Hawaii
    ( 2018-12) Tramontano, Rocoo ; Singh, Amarjit ; Singh, Amarjit
    This report will examine the application of plasma arc gasification technology to the City and County of Honolulu for the disposal of municipal solid waste. The report will examine history of the technology, the technology itself, and how it can be used to address the existing concerns of the traditional disposal methods of municipal solid waste. The environmental aspects of the technology and its implications will be presented and compared to the traditional WTE process of incineration. Additionally, we will further examine the major financial and economic implications associated of the technology. In a basic explanation, plasma arc gasification is the process where feedstock material (municipal solid waste, construction & demolition debris, hazardous waste, ash, etc.) is burned at extremely high temperatures that creates a molten slag byproduct that can be used for construction applications when cooled, and a synthetic gas that can be used as fuel for electricity. The technology of Alter NRG, the parent company of Westinghouse Plasma Corporation is an industry leader in plasma technology and its application using municipal solid waste will be applied to this study. Their G65 reactor is capable of processing 1000 tons of feedstock (municipal solid waste) that would create 250 tons of slag, 41 net MW of electricity, and send 20 tons of waste to landfill (2% of the initial feedstock) that cannot be recycled through the plant. Our analysis breaks down the cost per ton to process municipal solid waste as a feedstock, and compares it to the existing facilities and technology used on the island. At the end of our analysis it was found that plasma arc gasification can generate a positive net revenue of up to $168 per ton of municipal solid waste depending on the feedstock. What makes this technology so profitable is the high cost of electricity in the State of Hawaii, which is three times the national average across all sectors. The electricity generated can be sold to the Hawaiian Electric Company for profit. Other sources of revenue generated are gate fees to process the waste, recycling of ferrous and nonferrous recyclable materials prior to processing, and the sale of the inert slag byproduct. Together these revenue streams from PAG in Hawaii offset the capital cost of $341.5 million to construct a 1000 ton per day facility. This study will attempt to show how this technology can be a solution to Oahu’s waste predicament as the existing landfill only has the capacity to last less than 25 more years, and how unique factors present in the State of Hawaii could make this technology both environmentally and economically profitable.
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    ANALYSIS OF MAINTENANCE OF CRITICAL UTILITY SYSTEMS ON U.S. NAVY INSTALLATIONS TO DETERMINE OPTIMUM TIMING FOR RECAPITALIZATION
    ( 2023-12) Aderibigbe, Keji ; Singh, Amarjit ; Akiona, Randall ; Robertson, Ian ; Singh, Amarjit ; Akiona, Randall ; Robertson, Ian
    The Naval Facilities Engineering Systems Command (NAVFAC) is responsible for providing Facility Management and Sustainment (FM&S) services for all U.S. Navy installations worldwide. A critical element of this service is maintaining critical utility infrastructure that is key to operating these installations. Currently, most of the critical utility infrastructure systems – electrical, potable water, and wastewater – on U.S. Navy installations are near or past their useful life. When infrastructure start to degrade, the U.S. Navy allocate funds for recapitalization, but budget constraints have made it difficult to predict the timing of this investment and so facility managers must determine how to best extend the life of their utility infrastructure. The purpose of this report is to conduct an analysis of NAVFAC’s preventive maintenance (PM) strategy, performance, and U.S. Navy’s utility infrastructure investment by: • Analyzing the PM strategies NAVFAC uses for facility maintenance on U.S. Navy installations. • Researching PM strategies used in the facility management industry. • Analyzing the PM completion rates for utility systems on U.S. Navy Installations. • Analyzing the level of investment that the U.S. Navy’s provides for maintenance of utility systems. • Determine the optimum time for investing in the recapitalization of critical utility systems at U.S. Navy installations. The methodology used for this report analyzed different processes and reviewed data for the items associated with the report’s objective. The methods include: • Interviewing facility management teams within NAVFAC to determine the PM strategies used at their installations. • Interviewing facility managers outside the Department of Defense to determine their organization’s maintenance strategy and use it as a point of comparison. • Reviewing data on the condition of critical utility systems on U.S. Navy installations. • Reviewing data of PM completion across the NAVFAC enterprise to determine if NAVFAC is meeting its 100% PM completion goal. • Reviewing data on the historical level of U.S. Navy’s investment for critical utility systems, to determine if it is adequate to maintain the systems. The analysis used data obtained from NAVFAC’s electronic facility management systems, and the notes from interviews conducted with facility managers at various U.S. Navy installations. Based on this analysis, the key findings of this report are: • NAVFAC-managed critical utility systems are old; with some past their useful life. • NAVFAC uses a combination of maintenance strategies to maintain its utility systems. • NAVFAC does not meet its PM completion goals. • Maintenance investment from the U.S. Navy is not adequate to maintain the systems. • The timing to receive funding for recapitalization is unpredictable, and utility systems do not compete well for funding during the project prioritization process. Based on these findings, some recommendations for prolonging the life of critical infrastructure and receiving funding for recapitalization include: • Incorporating elements of different maintenance strategies into NAVFAC’s PM strategy. • Addressing staffing issues to increase PM completion. • Advocating for increase in sustainment funding. • Advocating for increase in weighted priorities in the decision lens model, to increase the chances of utility infrastructure projects being selected for funding. • Advocating for targeted funding for recapitalization of utility infrastructure Navy wide. The optimum time to invest in recapitalization for critical utility infrastructure is when systems are at the most significant risk of failure – as determined by the facility condition assessment tools used by NAVFAC. However, the reality of funding unpredictability means that NAVFAC must implement a well-disciplined PM program to help extend the life of critical infrastructure and mitigate the risks associated with projects not being selected for funding during the project prioritization process.
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    POHAKULOA TRAINING AREA: FRAMING NEGOTIATIONS, ENVIRONMENTAL REMEDIATION, AND SUSTAINABLE PROCESSES FOR LONG-TERM USE
    ( 2024-05) Walton, James ; Singh, Amarjit ; Singh, Amarjit
    The Pohakuloa Training Area (PTA), located on the Island of Hawai’i, is a critical military training installation used by the U.S. Army and joint forces in the Indo-Pacific Area of Operations. This report reviews the environmental remediation requirements and sustainable processes necessary for extending the Army Land Lease Agreement with the State of Hawai’i, focuses on unexploded ordnance (UXO) remediation techniques and procedures. PTA, spanning over 133,000 acres, is strategically vital for U.S. Indo-Pacific Command forces. However, the presence of UXOs, hazardous materials, and cultural sensitivities presents challenges to renewing the existing lease set to expire in 2029. The U.S. Army currently leases approximately 22,000 acres from the State of Hawai’i. The lease agreement has been under much scrutiny due to environmental concerns and a lawsuit resulting in the development of a state mandated management plan. Key proposed actions for upcoming negotiations include ‘Full Retention’ (retain the entire 22,000 acres), ‘Modified Retention’ (retain ~ 19,700 acres), and ‘Minimum Retention and Access’ (retain ~ 10,100 acres and limited road access). This report addresses environmental challenges and data gaps in recent environmental impact statements by the executive agent overseeing the real estate transaction, the U.S. Army Corps of Engineers. The report offers an overview of UXO and environmental regulatory frameworks, and proposes techniques for Cost Engineering Requirements, UXO and environmental control and monitoring, and emerging technologies and procedures for remediation activities. Furthermore, the report closely examines the land lease agreement through evaluating historical context, cultural perspectives, legal and regulatory variables, and offers negotiation techniques and best alternatives to negotiated agreements. The report underscores the critical importance of UXO remediation at PTA and recommends leveraging advanced technologies and negotiation strategies to ensure environmental sustainability and maintain military readiness. Implementing comprehensive environmental monitoring systems and cost-effective remediation techniques will be essential for a favorable lease agreement with the State of Hawai’i.
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    A Feasibility Study on the Implementation of 100% Electric Buses in the State of Hawai'i
    ( 2020-05) Phillip, Solomon ; Singh, Amarjit ; Akiona, Randall ; Shen, Lin
    This research will examine the feasibility of converting the present inventory of public transportation buses in the state of Hawaii to 100% battery-electric powered buses, along with all the necessary infrastructure modifications and additions. Moving forward, the term “e-bus” will be used to refer to a fully battery-electric powered, public transportation bus. It is imperative to understand that this study solely focuses on the public transportation bus system and does not include regular electric vehicles (EVs), publicly or privately owned.
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    Identifying Delamination in Airport Pavement at HNL with Embedded Asphalt Strain Gages
    ( 2019-06) Riege, Matthew ; Singh, Amarjit
    The demand of air transportation requires high levels of performances from asphalt pavements. Failures of pavements can delay flights, damage airplanes, and require costly expedient repairs. Common failures airport pavements are slippage failures including surface shoving and slippage cracking. Slippage failure is typically caused by either the deterioration of bonding between asphalt layers (delamination) or a lack of shear resistivity within the surface layer asphalt mix. Bonding between asphalt layers can be measured using embedded asphalt strain gages. In 2018, an asphalt strain gage system was installed at Daniel K. Inouye International Airport (HNL), Honolulu, HI. This report details the background of pavement monitoring at HNL, collection and processing of strain data, and analyzes the strain responses collected. Indicators of delamination are identified either through large discrepancies in peak strain experienced in asphalt layers or a low correlation of strain responses from the force of an airplane on the pavement. Data collected for this report is the start of an aggregated comparison to determine performance of installed pavement versus design. Ideally this comparison will take data from installation of overlay layer until replacement. Statistical analysis methods are employed to determine if recordings and calculated amounts are comparable across the time frame of this report. Results of this report are that pavement installed in August of 2018 has indicators of delamination, but is performing as a homogenous well bonded pavement. There are several items noted that require further monitoring and visual inspection. There are recommendations for follow on work under this project.
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    Plasma Arc Gasification Plant Benefits to the County of Hawaii
    ( 2022-12) Logan, Lydia ; Singh, Amarjit
    This report will examine the application and benefits of constructing a Plasma Arc Gasification plant on the Island of Hawaii. First, the waste composition and generation of the United States is discussed along with the current methods of disposal and their implications. Then, specifically the Island of Hawaii waste generation and management is analyzed. The State of Hawaii faces unique challenges of waste management due to its geographic isolation; this makes it a perfect candidate for a waste to energy technology. Incineration is a typical waste to energy technology but emits hazardous toxins and greenhouse gases through the combustion of waste. Plasma Arc Gasification however, uses extreme heat to vaporize the waste and converts it back into its elemental compounds. This process creates a syngas that can be used as fuel for electricity and a molten slag that is applicable as aggregate to the construction industry. Plasma Arc Gasification has multiple benefits including a flexible feedstock, electricity generation, a byproduct of non-hazardous slag. A cost analysis is performed comparing the current landfill operations with the potential profit of a Plasma Arc Gasification plant. A 1000 tpd PAG plant is used for this analysis because even though the Island of Hawaii disposed of approximately 185,000 tons of MSW in 2020, the waste disposal rate for the island on average increases 4.6 percent per year. The cost analysis determines that by constructing a PAG plant on the Island of Hawaii, there is a potential profit of $227.87 per ton of MSW, that equates to over $41 million a year. Compared to the current landfill operation there would be a net gain of $202.29 per ton of MSW or more than $37 million a year. The high initial capital cost of constructing a Plasma Arc Gasification plant is offset by its revenue generation.
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    Corrosion tests in Hawaiian geothermal fluids
    (National Research Council of Canada, 1984) Larsen-Basse, Jorn ; Lam, Kam-Fai
    Exposure tests were conducted in binary geothermal brine on the island of Hawaii. The steam which flashes from the high pressure, high temperature water as it is brought to ambient pressure contains substantial amounts of H2S. In the absence of oxygen this steam is only moderately aggressive but in the aerated state it is highly aggressive to carbon steels and copper alloys. The liquid after flashing is intermediately aggressive. The Hawaiian fluid is unique in chemistry and corrosion behavior; its corrosiveness is relatively mild for a geothermal fluid falling close to the Iceland-type resources.
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    Hawaii Geothermal Project : the effect of steady withdrawal of fluid in geothermal reservoirs
    (Hawaii Geothermal Project, University of Hawaii at Manoa, 1975) Cheng, Ping ; Lau, Kah Hie
    The problem of combined free and forced convection in geothermal reservoirs resulting from steady withdrawal of fluid is investigated numerically. The aquifer is confined by caprock on the top, heated by an impermeable surface at the bottom, and is recharged continuously from the ocean. The governing quasilinear partial differential equations in terms of pressure and temperature are approximated by finite difference equations which are solved numerically by iteration. Computations were carried out for both cylindrical and rectangular reservoirs for a selected set of parameters. It is found that the withdrawal rates and the location of the withdrawal site have a significant effect on heat transfer and fluid flow characteristics in a geothermal reservoir.
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    Hawaii Geothermal Project : the effect of dike intrusion on free convection in geothermal reservoirs
    (Hawaii Geothermal Project, University of Hawaii at Manoa, 1974) Lau, Kah Hie ; Cheng, Ping
    A perturbation analysis is made for the simultaneous heat and mass transfer in unconfined geothermal reservoirs with dike intrusion. The perturbation equations are of elliptic type that can be solved numerically by the finite difference method. Up to the second-order approximations are retained in the numerical computation. The effects of dike intrusion on streamlines, temperature distribution, and the shape of water table in two-dimensional aquifers with low permeability are shown.
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    Hawaii Geothermal Project : buoyancy induced flows in a saturated porous medium adjacent to impermeable horizontal surfaces
    (Hawaii Geothermal Project, University of Hawaii at Manoa, 1975) Cheng, Ping ; Chang, I-Dee
    Boundary-layer analysis is performed for the buoyancy-induced flows in a saturated porous medium adjacent to horizontal impermeable surfaces. Similarity solutions are obtained for the convective flow above a heated surface or below a cooled surface, where wall temperature is a power function of distance from the origin. Analytical expressions for boundary layer thickness, local and overall surface heat flux are obtained. Applications to convective flow in a liquid-dominated geothermal reservoir are discussed.