Sand dams are small, reinforced barriers constructed across seasonal and ephemeral streams which trap water in sediments deposited. For these reservoirs to provide sustainable and dependable water supplies or valuable sand for other purposes, they should primarily fill with coarse sand rather than fine sediments. Excessive accumulation of fine sediments in sand dam reservoirs limits recharge and recoverable water. We describe a novel approach to preventing the accumulation of fine sediments in sand dam reservoirs by geomorphic management of reservoir sedimentation. We propose building sand dams with outlets at the foot of the dam to selectively trap coarse sediments (> 0.125 mm; Rouse number = 2.5) across a range of flows and sediment transport rates. An optimal outlet had an "Eiffel Tower" shape which maintains the desired Rouse number, ensuring finer particles will pass out of the reservoir remaining suspended, while coarser particles settle. HEC-RAS simulations confirm that these designs promote uniform coarse sediment deposition within the reservoir and perform effectively, with minimal deviation from the target Rouse number, with a mean squared error (MSE) of less than 1%. Alternative rectangular and circular base cutouts which can be readily made by embedding culvert pipe also performed well across a wide range of flows. These shapes are simpler to construct and maintain greater structural integrity than the more complex Eiffel Tower (ET) shape. While the ET shape gave the most consistent performance in our tests, simpler designs may offer a better balance between performance, ease of construction, and strength.

Low-head dams can be built in ephemeral streambeds to trap sediments which can store water or serve as sand reserves for other uses. For sand dams to provide sustainable and dependable water supplies, or to provide valuable sand for other purposes, these reservoirs should primarily fill with coarse sand rather than fine sediments. The problem of sand dams being negatively impacted by an excess of fine sediments is a widespread issue. In Kenya, 40-60 percent of sand dams are reported to be affected by this problem, which can limit their ability to recharge and provide recoverable water. We describe a novel approach to preventing collection of fine sediments by geomorphic management of reservoir sedimentation. Specifically, we suggest building dams with “Eiffel Tower” shaped outlets (broad at the base and narrowing with height) to remain open until the reservoir is sediment filled. The opening is designed to provide constant Rouse number of 2.5 for 0.125 mm grains so that regardless of flow, only sand of size greater than 0.125 mm will accumulate. Considering the limitations of 1-dimensional simulations in capturing edge effects, a stage discharge relationship acquired through HEC-RAS simulation is utilized to correct the opening. Numerical modeling confirmed that these outlets maintain constant bed shear stress, and thus promote the deposition of uniform coarse sediments within the reservoir regardless of riverine flow rate. The findings of the HEC-RAS simulation demonstrate that bottom-notch openings, especially those of the “Eiffel Tower” shape, exhibit superior performance with an MSE value of less than 1% when determining the deviation between the desired Rouse number (2.5) and the calculated Rouse number.

This contribution to the Women in Mechanical Engineering: Energy and Environment volume is targeted at women who are seeking nontraditional ways to contribute to advancing energy science and technology, combating climate change, or otherwise improving our environment. Numerous options exist for mechanical engineers to have a significant impact, whether in academia, industry, government, or other types of organizations. Through a series of five lessons learned while remaining curious throughout my career, I share my unique insights on various opportunities to have impact through broader, non-research contributions, particularly for PhD degree-holders. The first lesson is that contributions come in many forms and to not discount broader, non-research contributions. I discuss personal experiences and opportunities to make such contributions in the following areas: science and technology policy, as an academic faculty member, through engineering for global development, and in central university administration. The other lessons are that career goals and directions don't have to be fixed; that neither you nor anyone else can say for sure what the future holds; that sometimes the move that goes against conventional wisdom might really be the right one; and that it is most important to remain curious and open to different types of career opportunities.

Earth and Space Science Open Archive PosterOpen AccessYou are viewing the latest version by default [v1]A New Approach to the Siltation Problem in the Sand Storage DamAuthorsSevvalGuldureniDJoeEllingsoniDJohnSelkeriDKendraSharpGordonGrantiDSee all authors Sevval GuldureniDCorresponding Author• Submitting AuthorOregon State UniversityiDhttps://orcid.org/0000-0002-7925-7356view email addressThe email was not providedcopy email addressJoe EllingsoniDOregon State UniversityiDhttps://orcid.org/0000-0002-8969-5026view email addressThe email was not providedcopy email addressJohn SelkeriDOregon State UniversityiDhttps://orcid.org/0000-0001-9751-6094view email addressThe email was not providedcopy email addressKendra SharpOregon State Universityview email addressThe email was not providedcopy email addressGordon GrantiDOregon State UniversityiDhttps://orcid.org/0000-0002-3012-5192view email addressThe email was not providedcopy email address

The objective of this paper is to develop a methodology to better understand behavioral empathy in the design process for the purpose of addressing user needs. To accomplish this, content analysis was conducted on undergraduate student assignments that documented group projects designing a consumer product. Using qualitative data analysis, the assignments and presentations were coded for their levels of behavioral empathy, using a scale that applied psychology and design theories. The Interpersonal Reactivity Index was administered to the students to assess their trait empathy. Results from these two analyses showed little connection between levels of behavioral empathy and self-assessed trait empathy of the student groups. The student assignments did reveal empathic waves that demonstrated comprehension and application of expressed user needs, evidenced by ascending and descending the empathy scale. These results indicate that is it not trait empathy that leads to empathic design, but rather applied empathy in the design process; developing internal empathy is not sufficient if it does not effectively translate user needs to technical requirements in the final design.

While filtration, chlorination, and UV drinking water treatments are commonplace, globally an estimated 1.2 billion people continue to boil their drinking water over inefficient biomass fires instead because it allows them to use available resources paired with a time-tested and trusted method. Although boiling water is culturally well-established, there is vast potential to improve human health, environmental impact, and efficiency by leveraging the fact that a significant reduction in pathogenic microorganisms occurs at temperatures well below boiling through a process known as pasteurization. This paper presents the evaluation of a community-scale, biomass-powered, flow-through water pasteurization system that was designed to heat water to the temperature required for pasteurization to occur before recuperating heat while cooling treated water down to a safe-to-handle temperature. The system is then compared to other common thermal treatment methods including batch-boiling over open fires and improved cookstoves. Results from computational modeling and empirical analysis show that the water pasteurizer significantly increases the overall water treatment capacity (from 7.9 to 411 L/h, adjusted for one hour of treatment via household boiling and operation of the water pasteurizer at steady-state, respectively) and uses far less biomass fuel (from 22 to 5.5 g/L, adjusted for treatment of 1 L of water via household boiling and operation of the water pasteurizer at steady-state, respectively). Notable comparisons to the batch-boiling of water over institutional-sized traditional and improved cookstoves are also demonstrated. Further, the results of fecal indicator reduction through the system (8 log and 6 log reduction of E. coli and bacteriophage MS2, respectively) suggest compliance with US-EPA (6 log and 4 log reduction of E. coli and bacteriophage MS2, respectively) and WHO requirements (effluent concentrations below the detection limit, specified as <1 E. coli CFU/100 mL and <10 bacteriophage MS2 PFU/mL) for the reduction in and effluent concentration of E. coli and bacteriophage for water treatment processes. It is recommended that engineers continue to explore the use of heat transfer and microorganism reduction theory to design technologies that increase the capacity and efficiency for thermal water purification that uses locally-available biomass resources.

Often in engineering for global development, product designers do not have the time or resources to conduct long-term technology adoption studies with large sample sizes for every iteration of their design and therefore must rely on shorter, targeted studies that measure both the technical and user acceptance parameters. This work presents a combination of experimental engineering and rapid anthropological methods to provide a mixed-methods approach to evaluate and improve the design of a novel water treatment technology, the InStove Water Purifier. This product uses the principles of pasteurization and heat recuperation to theoretically reduce energy consumption for water purification by 97% in a continuous process, producing enough water for 1400 people each day. The case study in Mbale, Uganda, used rapid ethnographic methods that included participant observation, focal follow, and time allocation; and engineering performance experiments that included fuel efficiency tests, water bacteria measurements, and data collection of temperature and flow rates. Data from all methods were synthesized in a Diffusion of Innovations (DoI) framework to gain insight into potential barriers and benefits of adoption of the technology within this specific context. As defined in a DoI framework, potential benefits to adoption include decreased overall time and labor to purify water, decrease in use of biomass resources, increase in overall water throughput, and low learning curve for the product operator. Similarly, potential barriers to user acceptance include the trust required by users towards product efficacy, lack of customization, and potentially undesirable changes in time allocation and fuel wood preparation.

Energy access for all is the seventh Sustainable Development Goal (SDG) put forth by the United Nations in 2015. This initiative has been taken on by many non-governmental organizations (NGOs), national governments and communities alike. Traditional approaches to cooking often rely on three-stone fires (or other open wood fires). The smoke from these open cooking fires is known to cause significant negative health impacts, thus access to cleaner energy sources is especially important for to improve cooking conditions. One alternative cooking fuel is biogas, which has the advantages of smoke reduction, and decreased reliance on and impact of firewood collection. In this article, we develop a method of analyzing the feasibility of biogas projects for rural communities. The method enables both evaluation of an ideal digester design for specific environments and determination of the scale, cost, and yields of a biogas plant. For example, in a cooking application 1-m3 of biogas can be compared to 1.3 kg of firewood or approximately 10 minutes not spent collecting firewood. Such evaluation is critical to help communities and organizations determine whether or not this type of project is ideal for their environments. All too often, development project concepts are funded prematurely, before the realization that the implemented technology does not function properly or is unsustainable for specific applications. The feasibility analysis we describe is a contribution to the literature because it provides a condensed, simplified resource that enables development practitioners and communities to readily evaluate whether or not a biogas energy solution is appropriate and sustainable for their setting prior to investing valuable resources and time into implementation.

Access to water is extremely important in schools around the world, where students spend most of their day. As schools expand, particularly in areas with limited water resources, it is necessary to develop and manage water resources to ensure their sustainability. In this article we describe a method of analyzing water piping distribution networks using an open-source software package that allows practitioners to model the increased demands on water distribution systems associated with school growth. The methodology was then applied to the case study of a community-level water distribution system in rural Tanzania. This method is valuable because it is both condensed and easy to follow for those in the field with or without technical backgrounds. Minimal tools are needed for practitioners to develop their own system models (only a GPS, tape measurer, bucket, stopwatch and access to a computer with the software downloaded). Overall, this condensed written resource is more accessible than others available to many practitioners and thus improves the ease of modeling for pre-planning and analysis of expansion or other water distribution system modifications.

In a rush to attain the Sustainable Development Goal 6 (clean drinking water and sanitation), many technology-based water and sanitation projects lack a long-term maintenance program, particularly when the organization initiating and/or sponsoring the project is not located near the implementation site. Since 2015, Burleson (lead author) conducted three field study efforts on community drinking water projects in Eastern Uganda. In the field, Burleson observed the consequences of both good and bad maintenance programs in drinking water projects, underpinning the importance of maintenance programming at the outset of the project. Additionally, Uganda's water supply strategy of decentralization with an emphasis on stakeholder engagement across public, private, and community-based entities is presented and analyzed, of which only one of the three Ugandan projects discussed in this paper appears to comply with. The other two projects did not follow the country's multi-stakeholder framework, nor did they incorporate sufficient long-term sustainability plans and thus the projects were terminated by default. The third Ugandan project did incorporate long-term sustainability planning from the outset and was still operational three years after inception. We discuss the success or lack thereof for these three case studies with respect to the aspects listed above within a framework of assessing failure modes, including a particular focus on planning for maintainability. We will compare the failure modes of these three projects to four other water development projects in the literature, and will relate the impact of such planning to observe its project termination or longevity.

Researchers are calling on practitioners to use more robust mixed-method approaches in program and product evaluations in the global development sector. Using qualitative and quantitative research methods from both experimental engineering and applied anthropology fields can provide more holistic and accurate information regarding potential impact and application of a product or program in its actual usage context. This paper presents a mixed-method approach for the evaluation of a new water treatment technology, the InStove Water Purifier. A combination of technical and ethnographic methods are used to estimate the product's efficacy in a high-school dormitory in Mbale, a city in Eastern Uganda. Methods include participant observation, focal follow, time allocation and data collection of system parameters including fuel usage, flowrate, and temperature. Additionally, a holistic approach to water treatment implementation is applied by experimentally evaluating water storage treatment methods to prevent recontamination of water before its point-of-use. This study highlights the importance of method triangulation and, more specifically, the value of ethnographic methods to evaluate engineering solutions. While two methods concluded statistically insignificant results (time allocation and fuel usage) due to limited sample size and duration of the study, this work emphasizes the value that comes from working closely with end-users in an uncontrolled experimental environment. Informal interviewing during participant observation combined with time allocation and fuel usage data show a high potential for user acceptance due to the Purifier's time and fuel savings (42% and 67% savings; respectively), increased water capacity, and reduction of emissions. Potential barriers to user adoption of the Purifier, identified in this study, include the trust required by users, lack of water outlet temperature control, and a size change of fuel wood. These findings have been reported to InStove, the manufacturer of the product, to begin design modifications to improve its potential impact to users. Ultimately, this paper aims to encourage engineering practitioners to become more comfortable performing ethnographic methods and integrating qualitative data to more accurately evaluate their projects in the field and provide design changes that increase user adoption and sustained impact.

Approximately 14% of the world’s population — 1.1 billion people — live without access to any electricity, and countless more lack access to reliable electricity. This article looks at electrification opportunities via small hydropower strategically placed within rural communities. We approach the challenge through a unique blend of technical feasibility and policy/legal dimensions to create a “toolkit” that promotes small run-of-river hydropower development. This toolkit can be used by emerging economies to ensure that the necessary conditions are in place to facilitate successful development. It includes at a minimum: (1) assessment of site-specific hydropower resource potential; (2) a stable and accessible governance structure; and (3) social acceptability of development and an involved local community. Pakistan is used as a case study, because Pakistan is actively seeking to increase its power generation capacity, is rich in hydropower resources, and is in the process of amending its regulatory scheme.

ABSTRACTWhile global climate models (GCMs) are useful for simulating climatic responses to perturbations in the Earth's climate system, there are many instances where higher spatial resolution information is necessary. In all instances, interpretation of interpolated or downscaled GCMs must be done cautiously because each method has its own set of assumptions and potential disadvantages. Here, we present an update to the Global Climate Data (GCD) package, which enables the package to efficiently bias correct and interpolate precipitation and air temperature output from GCM simulations to very high spatial resolutions using the delta change method. While the delta change method is relatively simple, it has previously been shown to enhance the physical representation of interpolated climate time‐series compared to directly interpolating the gridded climate time‐series to a higher spatial resolution. The bias correction methods programmed into the GCD package are univariate empirical quantile mapping (QM) and bivariate empirical joint bias correction (JBC). The skill of QM and JBC for improving GCM simulations processed with the delta change method is evaluated through comparing the cumulative distribution functions (CDFs) of the interpolated GCM simulations to the CDFs of Global Historical Climatology Network (GHCN) station observations for three test regions: Oregon (in the USA), the Alps (spanning several countries in Europe), and the Ganges Delta (in India and Bangladesh). We also assess the representation of precipitation and mean temperature joint probability distributions relative to those present in GHCN station observations. Overall, GCM simulations that are bias corrected with QM prior to being input to the delta change method perform best under our analysis.

The engineering profession is increasingly recognizing that engineers’ abilities to utilize a systems perspective and collaborate on multidisciplinary teams are critical professional competencies required to solve contemporary engineering challenges. Understanding context, including but not limited to social and cultural context, is one aspect of systems thinking that is important to effective problem-solving, yet such training is not yet standard in our engineering curricula. Humanitarian engineering-related capstone design projects offer both hands-on and field opportunities to integrate social and cultural appropriateness into a formal engineering design curriculum. Over the 2015-2016 academic year, Oregon State University offered a capstone project aimed at optimizing and implementing an improved soap-making process for TERREWODE, a non-governmental organization in Uganda. The ultimate goal of this soap-making project was to expand income-generating opportunities for victims and survivors of obstetric fistula. The project consisted of a six-month, on-campus design phase and a three-week field implementation and research trip in Soroti, Uganda. Six Social Justice (SJ) criteria were used in assessing project context and developing design requirements. Throughout the design phase, experimental testing drove the majority of design decisions. During field implementation and research, the three-student capstone design team worked closely with TERREWODE and their members to optimize the process, understand cultural conditions, and recommend options for potential local solar power systems.

Abstract. Making meaningful projections of the impacts that possible future climates would have on water resources in mountain regions requires understanding how cryosphere hydrology model performance changes under altered climate conditions and when the model is applied to ungaged catchments. Further, if we are to develop better models, we must understand which specific process representations limit model performance. This article presents a modeling tool, named the Conceptual Cryosphere Hydrology Framework (CCHF), that enables implementing and evaluating a wide range of cryosphere modeling hypotheses. The CCHF represents cryosphere hydrology systems using a set of coupled process modules that allows easily interchanging individual module representations and includes analysis tools to evaluate model outputs. CCHF version 1 (Mosier, 2016) implements model formulations that require only precipitation and temperature as climate inputs – for example variations on simple degree-index (SDI) or enhanced temperature index (ETI) formulations – because these model structures are often applied in data-sparse mountain regions, and perform relatively well over short periods, but their calibration is known to change based on climate and geography. Using CCHF, we implement seven existing and novel models, including one existing SDI model, two existing ETI models, and four novel models that utilize a combination of existing and novel module representations. The novel module representations include a heat transfer formulation with net longwave radiation and a snowpack internal energy formulation that uses an approximation of the cold content. We assess the models for the Gulkana and Wolverine glaciated watersheds in Alaska, which have markedly different climates and contain long-term US Geological Survey benchmark glaciers. Overall we find that the best performing models are those that are more physically consistent and representative, but no single model performs best for all of our model evaluation criteria.

TERREWODE, a non-governmental organization in Uganda, works to eradicate obstetric fistula in local communities and provide income-generating skills training to the affected women. Obstetric fistula is a traumatic childbirth injury caused by prolonged, obstructed labor and delayed intervention. The condition is preventable with proper medical attention, however, in rural areas women who suffer from the condition are typically disowned from their families and communities [1]. As part of their social reintegration program, TERREWODE provides training for women post-treatment in multiple income-generating skill areas; jewelry making, baking, cooking, sewing, and buying/selling produce. The soap-making idea originated within TERREWODE itself and is intended to create an income stream for the women participating. The scope of this senior capstone project, in collaboration with several organizations, is to increase efficiency, reliability, and repeatability of the soap-making process and explore potential avenues for powering the system in an off-grid setting. A weighted-design matrix was used to make engineering decisions throughout the project. The two primary engineering aspects of this project were the selection of soap-making process (hot vs. cold) and the selection of a mixing device and powering unit. Understanding of appropriate manufacturing technologies in Uganda was necessary as all materials and tools needed to be locally available for success for the project. The hot process requires maintaining the soap mixture at a constant temperature for roughly two hours or until the gel phase occurs. This process allows for a short curing time, permitting the soap to be ready for use sooner. Opposing this, the cold process requires little cook time but a lengthy curing time. Experimental data showed that maintaining a consistent temperature over an extended period of time while using a cookstove is nearly impossible, even in a controlled lab environment. The cold process was selected as a better suited solution for manufacturing due to field conditions and available resources. A mixing device is crucial to the soap-making process. Due to the unreliability of grid-based electricity in the region, the team considered both a human-powered mixing solution and a solar-powered mixing solution [2]. TERREWODE leadership steered the team away from creating a human powered bike mixer for fear of discouraging women to participate, due to potential health and comfort issues. The team selected a solar powered system and has tested a U.S. manufactured prototype. The ultimate goal of this soap-making project is to provide an opportunity for victims and survivors of obstetric fistula to earn a livelihood. The work done by the Oregon State (OSU) mechanical engineering design team, in conjunction with the OSU Anthropology department, University of Oregon College of Business, several private artists and entrepreneurs, and TERREWODE, will provide potential improvements to the process and implementation plan to more effectively and economically create soap.

Small-scale hydropower systems are popular both in the United States and much of the developing world due to the emphasis on renewable energy and the general cost-competitiveness of hydroelectric power generation. We present a novel modeling package, referred to as the Hydropower Potential Assessment Tool (HPAT), to assess historic and projected future small-scale run-of-river hydropower resource potential at a single location or distributed over a study region. HPAT implements a fully-distributed streamflow model, which is coupled to a digital elevation model to assess hydropower resource potential. To demonstrate HPAT, we implement the models for a privately-owned run-of-river facility on Falls Creek outside of Sweet Home, Oregon, USA. We use an ensemble of Global Climate Models (GCMs) for two future climate scenarios to project a plausible range of future changes at this site. For the Falls Creek facility, HPAT projects that the timing of peak streamflow will shift from spring to winter and that mean annual hydropower potential will likely decrease slightly from average 1980–2010 historic conditions through the end of the 21st century. All inputs to HPAT are globally available, except for streamflow observations necessary for calibration.

Obstruction of fluid flow by stationary bubbles in a microchannel hemodialyzer decreases filtration performance and increases damage to blood cells through flow maldistribution. A polyethylene oxide (PEO)-polybutadiene (PB)-polyethylene oxide surface modification, previously shown to reduce protein fouling and water/air contact angle in polycarbonate microchannel hemodialyzers, can improve microchannel wettability and may reduce bubble stagnation by lessening the resistive forces that compete with fluid flow. In this study, the effect of the PEO-PB-PEO coating on bubble retention in a microchannel array was investigated. Polycarbonate microchannel surfaces were coated with PEO-PB-PEO triblock polymer via radiolytic grafting. Channel obstruction was measured for coated and uncoated microchannels after injecting a short stream of air bubbles into the device under average nominal water velocities of 0.9 to 7.2 cm/s in the channels. The presence of the PEO coating reduced obstruction of microchannels by stationary bubbles within the range of 1.8 to 3.6 cm/s, average nominal velocity. Numerical simulations based on the lattice Boltzmann method indicate that beneficial effects may be due to the maintenance of a lubricating, thin liquid film around the bubble. The determined effective range of the PEO coating for bubble management serves as an important design constraint. These findings serve to validate the multiutility of the PEO-PB-PEO coating (bubble lubrication, biocompatibility, and therapeutic loading). © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 941-948, 2016.

This paper highlights the influence of contact line (pinning) forces on the mobility of dry bubbles in microchannels. Bubbles moving at velocities less than the dewetting velocity of liquid on the surface are essentially dry, meaning that there is no thin liquid film around the bubbles. For these "dry" bubbles, contact line forces and a possible capillary pressure gradient induced by pinning act on the bubbles and resist motion. Without sufficient driving force (e.g., external pressure), a dry bubble is brought to stagnation. For the first time, a bipartite theoretical model that estimates the required pressure difference across the length of stagnant bubbles with concave and convex back interfaces to overcome the contact line forces and stimulate motion is proposed. To validate our theory, the pressure required to move a single dry bubble in square microchannels exhibiting contact angle hysteresis has been measured. The working fluid was deionized water. The experiments have been conducted on coated glass channels with different surface hydrophilicities that resulted in concave and convex back interfaces for the bubbles. The experimental results were in agreement with the model's predictions for square channels. The predictions of the concave and convex back models were within 19% and 27% of the experimental measurements, respectively.