Digital Commons Network^™

A Case For Weakening Patent Rights

Joshua M. Pearce

No abstract provided.

Influence Of Oxygen Concentration On The Performance Of Ultra-Thin Rf Magnetron Sputter Deposited Indium Tin Oxide Films As A Top Electrode For Photovoltaic Devices, Jephias Gwamuri, Murugesan Marikkannan, J. Mayandi, Patrick Bowen, Joshua M. Pearce

Joshua M. Pearce

The opportunity for substantial efficiency enhancements of thin film hydrogenated amorphous silicon (a-Si:H) solar photovoltaic (PV) cells using plasmonic absorbers requires ultra-thin transparent conducting oxide top electrodes with low resistivity and high transmittances in the visible range of the electromagnetic spectrum. Fabricating ultra-thin indium tin oxide (ITO) films (sub-50 nm) using conventional methods has presented a number of challenges; however, a novel method involving chemical shaving of thicker (greater than 80 nm) RF sputter deposited high-quality ITO films has been demonstrated. This study investigates the effect of oxygen concentration on the etch rates of RF sputter deposited ITO films to …

Controlling Optical Absorption In Metamaterial Absorbers For Plasmonic Solar Cells, Wyatt Adams, Ankit Vora, Jephias Gwamuri, Joshua M. Pearce, Durdo O. Guney

Joshua M. Pearce

Metals in the plasmonic metamaterial absorbers for photovoltaics constitute undesired resistive heating. However, tailoring the geometric skin depth of metals can minimize resistive losses while maximizing the optical absorbance in the active semiconductors of the photovoltaic device. Considering experimental permittivity data for InxGa1-xN, absorbance in the semiconductor layers of the photovoltaic device can reach above 90%. The results here also provides guidance to compare the performance of different semiconductor materials. This skin depth engineering approach can also be applied to other optoelectronic devices, where optimizing the device performance demands minimizing resistive losses and power consumption, such as photodetectors, laser diodes, …

Educational Pathways To Remote Employment In Isolated Communities, David C. Denkenberger, Julia Way, Joshua M. Pearce

Joshua M. Pearce

Those who live in isolated communities often lack reliable, skilled employment opportunities, which fundamentally undermines their human security. For individuals who wish to remain in their isolated communities for family, religious, philosophical or other reasons, their attachment to their communities creates a disincentive for higher education. This promotes low educational achievement, which in turn results in low socioeconomic status, lack of social mobility, and a generational cycle of poverty. The human misery that results from such a feedback loop is observed in isolated communities throughout North America, including aboriginal communities in Canada. Fortunately, maturation of information and communication technologies now …

Cost-Effectiveness Of Interventions For Alternate Food To Address Agricultural Catastrophes Globally, David C. Denkenberger, Joshua M. Pearce

Joshua M. Pearce

The literature suggests there is about a 1 % risk per year of a 10 % global agricultural shortfall due to catastrophes such as a large volcanic eruption, a medium asteroid or comet impact, regional nuclear war, abrupt climate change, and extreme weather causing multiple breadbasket failures. This shortfall has an expected mortality of about 500 million people. To prevent such mass starvation, alternate foods can be deployed that utilize stored biomass. This study developed a model with literature values for variables and, where no values existed, used large error bounds to recognize uncertainty. Then Monte Carlo analysis was performed …

Emergence Of Home Manufacturing In The Developed World: Return On Investment For Open-Source 3-D Printers., Emily E. Petersen, Joshua M. Pearce

Joshua M. Pearce

Through reduced 3-D printer cost, increased usability, and greater material selection, additive manufacturing has transitioned from business manufacturing to the average prosumer. This study serves as a representative model for the potential future of 3-D printing in the average American household by employing a printer operator who was relatively unfamiliar with 3-D printing and the 3-D design files of common items normally purchased by the average consumer. Twenty-six items were printed in thermoplastic and a cost analysis was performed through comparison to comparable, commercially available products at a low and high price range. When compared to the low-cost items, investment …

Emerging Business Models For Open Source Hardware, Joshua M. Pearce

Joshua M. Pearce

The rise of Free and Open Source models for software development has catalyzed the growth of Free and Open Source hardware (also known as “Libre Hardware”). Libre Hardware is gaining significant traction in the scientific hardware community, where there is evidence that open development creates both technically superior and far less expensive scientific equipment than proprietary models. In this article, the evidence is reviewed and a collection of examples of business models is developed to service scientists who have the option to manufacture their own equipment using Open Source designs. Profitable Libre Hardware business models are reviewed, which includes kit, …

Open-Source 3-D Printing Technologies For Education: Bringing Additive Manufacturing To The Classroom, Chelsea Schelly, Gerald C. Anzalone, Bas Wijnen, Joshua M. Pearce

Joshua M. Pearce

Objective 3-D printing technologies have the potential to improve both Science, Technology, Engineering, and Mathematics (STEM) education and Career and Technical Education (CTE), as well as integrating these two educational emphases and providing opportunities for cross-curriculum engagement. The objective of this study is to investigate the potential of open-source (OS) technologies in an educational setting, given the combination of economic constraints affecting all educational environments and the ability of OS design to profoundly decrease the cost of technological tools and technological innovation. Methods This paper reports on a 3-day workshop augmented with online instructional and visual tools designed for middle …

Maximizing Return On Investment For Public Health With Open-Source Medical Hardware, Joshua M. Pearce

Joshua M. Pearce

No abstract provided.

Service Learning In Engineering, Angela R. Bielefeldt, Joshua M. Pearce

Joshua M. Pearce

No abstract provided.

Effects On Amorphous Silicon Photovoltaic Performance From High-Temperature Annealing Pulses In Photovoltaic Thermal Hybrid Devices, M. Pathak, Joshua M. Pearce, S. J. Harrison

Joshua M. Pearce

There is a renewed interest in photovoltaic solar thermal (PVT) hybrid systems, which harvest solar energy for heat and electricity. Typically, a main focus of a PVT system is to cool the photovoltaic (PV) cells to improve the electrical performance; however, this causes the thermal component to under-perform compared to a solar thermal collector. The low temperature coefficients of amorphous silicon (a-Si:H) allow the PV cells to be operated at high temperatures, which are a potential candidate for a more symbiotic PVT system. The fundamental challenge of a-Si:H PV is light-induced degradation known as the Staebler–Wronski effect (SWE). Fortunately, SWE …

Expanded Microchannel Heat Exchanger: Design, Fabrication And Preliminary Experimental Test, David C. Denkenberger, Michael J. Brandemuehl, Joshua M. Pearce, John Zhai

Joshua M. Pearce

This article first reviews non-traditional heat exchanger geometry, laser welding, practical issues with microchannel heat exchangers, and high effectiveness heat exchangers. Existing microchannel heat exchangers have low material costs, but high manufacturing costs. This article presents a new expanded microchannel heat exchanger design and accompanying continuous manufacturing technique for potential low-cost production. Polymer heat exchangers have the potential for high effectiveness. This article discusses one possible joining method – a new type of laser welding named ‘forward conduction welding’, used to fabricate the prototype. The expanded heat exchanger has the potential to have counter-flow, cross-flow, or parallel-flow configurations, be used …

Improved Performance Of Hydbrid Photovoltaic-Trigeneration Systems Over Photovoltaic-Cogen Systems Including Effects Of Battery Storage, Amir H. Nosrat, Lukas G. Swan, Joshua M. Pearce

Joshua M. Pearce

Recent work has proposed that hybridization of residential-scale cogeneration with roof-mounted solar PV (photovoltaic) arrays can increase the PV penetration level in ideal situations by a factor of five. In regions where there is a significant cooling load PV-cogen hybrid systems could be coupled to an absorption chiller to utilize waste heat from the cogen unit. In order to investigate realistic (non-ideal) loads that such a hybrid system would need to service, a new numerical simulation called PVTOM (PV-trigeneration optimization model) was created and coupled to the results of the established CHREM (Canadian Hybrid Residential End-Use Energy and Emissions Model). …

Commentary: Open-Source Hardware For Research And Education, Joshua M. Pearce

Joshua M. Pearce

No abstract provided.

Limitations Of Nuclear Power As A Sustainable Energy Source, Joshua M. Pearce

Joshua M. Pearce

This paper provides a review and analysis of the challenges that nuclear power must overcome in order to be considered sustainable. The results make it clear that not only do innovative technical solutions need to be generated for the fundamental inherent environmental burdens of nuclear energy technology, but the nuclear industry must also address difficult issues of equity both in the present and for future generations. The results show that if the concept of just sustainability is applied to the nuclear energy sector a global large-scale sustainable nuclear energy system to replace fossil fuel combustion requires the following: (i) a …

A Review Of Solar Photovoltaic Levelized Cost Of Electricity, K. Branker, M. Pathak, Joshua M. Pearce

Joshua M. Pearce

As the solar photovoltaic (PV) matures, the economic feasibility of PV projects is increasingly being evaluated using the levelized cost of electricity (LCOE) generation in order to be compared to other electricity generation technologies. Unfortunately, there is lack of clarity of reporting assumptions, justifications and degree of completeness in LCOE calculations, which produces widely varying and contradictory results. This paper reviews the methodology of properly calculating the LCOE for solar PV, correcting the misconceptions made in the assumptions found throughout the literature. Then a template is provided for better reporting of LCOE results for PV needed to influence policy mandates …

Optimizing Limited Solar Roof Access By Exergy Analysis Of Solar Thermal, Photovotaic, And Hybrid Thermal Systems, M. Pathak, P. G. Sanders, Joshua M. Pearce

Joshua M. Pearce

An exergy analysis was performed to compare a conventional (1) two panel photovoltaic solar thermal hybrid (PVT x2) system, (2) side by side photovoltaic and thermal (PV + T) system, (3) two module photovoltaic (PV) system and (4) a two panel solar thermal (T x2) system with identical absorber areas to determine the superior technical solar energy systems for applications with a limited roof area. Three locations, Detroit, Denver and Phoenix, were simulated due to their differences in average monthly temperature and solar flux. The exergy analysis results show that PVT systems outperform the PV + T systems by 69% …

The Effects Of Dispatch Strategy On Electrical Performance Of Amorphous Silicon-Based Solar Photovoltaic-Thermal Systems, Joseph Rozario, A. H. Vora, S. K. Debnath, M. Pathak, Joshua M. Pearce

Joshua M. Pearce

Previous work has shown that high-temperature short-term spike thermal annealing of hydrogenated amorphous silicon (a-Si:H) photovoltaic thermal (PVT) systems results in higher electrical energy output. The relationship between temperature and performance of a-Si:H PVT is not simple as high temperatures during thermal annealing improves the immediate electrical performance following an anneal, but during the anneal it creates a marked drop in electrical performance. In addition, the power generation of a-Si:H PVT depends on both the environmental conditions and the Staebler–Wronski Effect kinetics. In order to improve the performance of a-Si:H PVT systems further, this paper reports on the effect of …

Mobile Open-Source Solar-Powered 3-D Printers For Distributed Manufacturing In Off-Grid Communities, Debbie L. King, Adegboyega Babasola, Joseph Rozario, Joshua M. Pearce

Joshua M. Pearce

Manufacturing in areas of the developing world that lack electricity severely restricts the technical sophistication of what is produced. More than a billion people with no access to electricity still have access to some imported higher-technologies; however, these often lack customization and often appropriateness for their community. Open source appropriate tech­nology (OSAT) can over­come this challenge, but one of the key impediments to the more rapid development and distri­bution of OSAT is the lack of means of production beyond a specific technical complexity. This study designs and demonstrates the technical viability of two open-source mobile digital manufacturing facilities powered with …

The Effects Of Snowfall On Solar Photovoltaic Performance, Rob W. Andrews, Andrew Pollard, Joshua M. Pearce

Joshua M. Pearce

Solar photovoltaic (PV) systems are frequently installed in climates with significant snowfall. To better understand theeffects of snowfall on the performance of PV systems, a multi-angle, multi-technology PV system was commissioned andmonitored over two winters. A novel methodology was introduced and validated with this system, which allows for thedetermination of snowfall losses from time-series performance data with correlated meteorological observations down toa 5-minute resolution. In addition, a new method for determining the probability distribution of snow deposition on amodule from image data was developed. It was found that the losses due to snowfall are dependent on the angle andtechnology being …

A New Method To Determine The Effects Of Hydrodynamic Surface Coatings On The Snow Shedding Effectiveness Of Solar Photovoltaic Modules, Rob W. Andrews, Andrew Pollard, Joshua M. Pearce

Joshua M. Pearce

As solar photovoltaic (PV) installations have become more common in regions that experience substantialsnowfall, losses in energy production due to snow coverage have grown in concern. Several post-productionsurface coatings have been proposed to enhance snow shedding to reduce these snow related losses. In thispaper, a novel methodology is developed to determine the effectiveness of a snow clearing from a PV moduleand is used to evaluate the snow shedding effectiveness of any module surface treatment. Measured PVoutput is compared to modelled PV output in a generalizable method that allows for the determination of the length of time a panel is covered …

Simple And Low-Cost Method Of Planning For Tree Growth And Lifetime Effects On Solar Photovoltaic Systems Performance, C. Dereli, C. Yücedağ, Joshua M. Pearce

Joshua M. Pearce

The use of distributed solar photovoltaic (PV) systems is growing more common as solar energy conversion efficiencies increase while costs decrease. Thus, PV system installations are increasing in non-optimal locations such as those potentially shaded with trees. Tree-related shading can cause a significant power loss and an increasing collection of laws have been enacted and are under development to protect the right of PV owners to solar access. This paper provides a new method to predict the shading losses for a given tree species, orientation to a PV array, and geographic location using existing free tools in order to assist …

A New Model For Enabling Innovation In Appropriate Technology For Sustainable Development, Joshua M. Pearce, Scott Albritton, Gabriel Grant, Garrett Steed, Ivana Zelenika

Joshua M. Pearce

The task of providing for basic human necessities such as food, water, shelter, and employment is growing as the world’s population continues to expand amid climate destabilization. One of the greatest challenges to development and innovation is access to relevant knowledge for quick technological dissemination. However, with the rise and application of advanced information technologies there is a great opportunity for knowledge building, community in-teraction, innovation, and collaboration using various online platforms. This article examines the potential of a novel model to enable innovation for collaborative enterprise, learning, and appropriate technology development on a global scale.

Open-Source Development Of Solar Photovoltaic Technology, A. J. Buitenhuis, Joshua M. Pearce

Joshua M. Pearce

The rise of solar photovoltaic (PV) technology as a driver of rural electrification in the developing world and a contributor to climate change mitigation suggests that innovations enhancing PV efficiency and scalability could make considerable strides in reducing both poverty and greenhouse gas emissions. The nearly global access to the solar resource coupled to innovation-driven decreases in the costs of PV provides a path for a renewable energy source to accelerate sustainable development. Open-source software development has proven to produce reliable and innovative computer code at lower costs than proprietary software through sharing development responsibility with a large community of …

Evaluation Of Potential Fair Trade Standards For An Ethical 3-D Printing Filament, Savanna R. Feeley, Bas Wijnen, Joshua M. Pearce

Joshua M. Pearce

Following the rapid rise of distributed additive manufacturing with 3-D printing has come the technical development of filament extruders and recyclebots, which can turn both virgin polymer pellets and post-consumer shredded plastic into 3-D filament. Similar to the solutions proposed for other forms of ethical manufacturing, it is possible to consider a form of ethical 3-D printer filament distribution being developed. There is a market opportunity for producing this ethical 3-D printer filament, which is addressed in this paper by developing an “ethical product standard” for 3-D filament based upon a combination of existing fair-trade standards and technical and life …

Effects Of Spectral Albedo On Solar Photovoltaic Devices, M. P. Brennan, A. L. Abrahamse, Rob W. Andrews, Joshua M. Pearce

Joshua M. Pearce

Although the spectral effects of direct and diffuse radiation on solar photovoltaic (PV) performance are relatively well understood, recent investigations have shown that there can be a spectral bias introduced due to albedo from common ground surfaces that can impact the optimal selection of PV materials for a known location. This paper extends analysis to the effects of spectral bias due to the specular reflectivity of 22 commonly occurring surface materials (both man-made and natural) and analyzes the albedo effects on the performance of seven PV materials covering three common PV system topologies: industrial (solar farms), commercial flat rooftops and …

Community Voices: Perspectives On Renewable Energy In Nunavut, Nicole C. Mcdonald, Joshua M. Pearce

Joshua M. Pearce

Nunavut communities currently depend on imported diesel fuel for virtually all of their energy needs. This dependency not only hinders the ability of communities to be self-sufficient, but also has negative impacts on their environment, health, and social well-being. The current practices waste 65% of the energy created and place a serious economic strain on the society by consuming 20% of the government’s annual budget. Although renewable energy technologies (RETs) could partially offset diesel use, there is a lack of sufficient information to mold appropriate policy. This investigation of community perspectives contributes to information needed to develop sustainable energy policies …

Toward Renewable Eenergy Geo-Information Infrastructures: Applications Of Giscience And Remote Sensing That Build Institutional Capacity, K. Calvert, Joshua M. Pearce, W. E. Mabee

Joshua M. Pearce

Sustained policy support is necessary in order to drive a transition toward renewable energy (RE). The ability to realize RE policy objectives is constrained by a range of geographic factors related to resource potential, the distribution of resources, land availability/suitability, the absorptive capacity of proximal infrastructure, and local socio-political acceptance. With this in mind, this paper provides a systematic review of how geographic information science and remote sensing techniques have been applied to reduce uncertainties surrounding renewable energy development, with emphasis on policy and planning needs. The concept of a ‘geo-information infrastructure’ is used to bring coherence and direction to …

Environmental Impacts Of Distributed Manufacturing From 3-D Printing Of Polymer Components And Products, Megan Kreiger, Joshua M. Pearce

Joshua M. Pearce

Although additive layer manufacturing is well established for rapid prototyping the low throughput and historic costs have prevented mass-scale adoption. The recent development of the RepRap, an open source self-replicating rapid prototyper, has made low-cost 3-D printers readily available to the public at reasonable prices (

As the open source 3-D printers continue to evolve and improve in both cost and performance, the potential for economically-viable distributed manufacturing of products increases. Thus, products and components could be customized and printed on-site by individual consumers as needed, reversing the historical trend towards centrally mass-manufactured and shipped products. Distributed manufacturing reduces embodied …

Barriers To Appropriate Technology Growth In Sustainable Development, Ivana Zelenika, Joshua M. Pearce

Joshua M. Pearce

Given the urgency of development problems world-wide, as well as the opportunities of open source appropriate technology (OSAT) to help expedite sustainable development goals, a better understanding of the barriers limiting the scaling of OSAT is needed. In this study, key organizations and researchers working in the field of appropriate technology (AT) were interviewed to identify barriers to OSAT. The data was analyzed via pattern coding and content analysis. Results reveal that among the most pressing problems for those working in the field of AT were the need for better communication and collaboration between the agencies and communities to share …