Resistivity as Dynamic Behavior in Low Density Polyethylene

Bridging the gap between theoretical calculations and experimental data has been the focus of much of the research into the electrical behavior of insulating polymers. Low density polyethylene is the standard test material used in both experimental work and numerical calculations. Resistivity measurements provide more than an absolute value for technical use; they also provide insight into the nature of active charge carriers and trapping behavior within LDPE

Dependence of Resistivity in Low-Density Polyethylene on Space Environment Parameters

The conductivity of high-resistivity polymer films is dependent on the magnitude of applied electric field, repeated electric field exposure, and sample temperature. A traditional constant voltage method was used, maintained under vacuum to more closely resemble the space environment. Both the strength of the applied voltage and the thickness of low-density polyethylene (LDPE) samples were varied to determine the electric field dependence of internal polarization and the leakage current most appropriate in calculating the resistivity. Repetition of same field strength measurements determined the influence of sample history and charging memory. Measuring the resistivity from cryogenic temperatures to well above the glass transition temperature of LDPE allowed for separation of hopping conductivity regimes and correlation with internal morphology. In combination, these measurements provide a picture of the resistivity behavior of LDPE

Break-Out Session 3: the Northern Rockies

Four characteristics of the Northern Rockies that are most important to ecosystem management are the large number of high-profile wildlife species, the diversity of ecological types, the rural socio-economic systems that are highly resource-based, and the fire-dependent natural systems. Potential constraints include the diversity of human values, insufficient knowledge about ecosystems, the tendency for political systems to produce solutions that are not ecologically optimal, and the prevalence of a utilitarian growth orientation coupled with anti-government sentiment. Characteristics most favorable for EM are the large amount of federal ownership, abundant research opportunities, a growing public recognition of the need to make environmental progress, and recognition among the agencies of the need for partnerships

Engaging Faculty in Preparing Students for Non-Academic Environmental Careers

As a biology major at New York University, I was introduced to ecology in a course that bused the class out of New York University\u27s Greenwich Village campus every weekend, to investigate biodiversity patterns in nearby forests and wetlands. After a day crossing bogs and walking through forests, I would take the subway home, hip boots in hand, reflecting on how the day\u27s activities connected to my routine city life. Engaging others in understanding the city connections to adjacent habitats became my life\u27s work. As Dean of Arts and Sciences at a public liberal arts university, I encourage faculty and students to engage in connecting classroom knowledge to real‐world problem solving, as required in non‐academic environmental careers. – CR

HELWAVE: High Efficiency Low Wake Aquatic Vehicle Exterior

This project seeks to find if it is possible to apply soliton theory to reduce or eliminate surface disturbances that a watercraft produces as it moves. It aimed to do so by developing several unique hull shapes crafted from the principles of soliton theory that were optimized for different sizes and styles of vessel. The solitons used were derived from sets of partial differential equations whose solution has the unique ability to maintain its shape as it propagates. Through a combination of modeling programs and advanced manufacturing methods, students created physical and computer models to test the soliton boat design. Utilizing Embry-Riddle’s new non-linear wave lab, students were able to take measurements using high definition and high speed cameras in such a way that the fluid flow around the ship could be recorded. In combination with computer simulations, this quantitative data was analyzed and resulted in HELWAVE’s conclusion surrounding the application of solitons

AN INVESTIGATION OF SUSTAINABLE FLUORIDE WATER TREATMENT TECHNOLOGIES WITH A FOCUS ON ETHIOPIA

Human consumption of unsafe drinking water from an unimproved source is a global issue affecting approximately 748 million people worldwide. While this number has been decreasing in recent years, an additional 1.2 billion people are estimated to lack access to water that is consistently free from health risks. This dissertation begins with a literature review investigating drinking water improvement initiatives around the world and a discussion of reasons why these initiatives often fail. Resources are provided for researchers and practitioners working on drinking water treatment implementations and examples of implementations that have failed or succeeded are discussed. The conclusion from this review is that global drinking water solutions will be more effective when designed and implemented by personnel from multiple disciplines. For example, people in several fields, including: social sciences, engineering and business, should collaborate and share ideas and expertise. Ideally this collaboration should start at the genesis of a project and continue through implementation and follow up. There is hope that the synergistic efforts of multidisciplinary teams will help to increase the number of successful water initiatives. Next the dissertation focuses on the problem of elevated fluoride concentrations in drinking water. Naturally occurring fluoride is the second largest issue contributing to the global water crisis. It is estimated that globally over 200 million people are affected by elevated concentrations of fluoride in drinking water. The goal of the technical portion of this dissertation is to investigate locally available and sustainable materials that can be used to remove fluoride from drinking water, with a focus on Ethiopia and eastern Sub-Saharan Africa. Bone char is very effective as an adsorptive material, but is not always accepted by communities due to religious or cultural beliefs. Therefore, this research evaluated methods to improve the fluoride removal capacity of bone char as well as investigated materials that might serve as a replacement for bone char in appropriate communities. Eucalyptus trees are prevalent in Ethiopia where a large fluoride problem exists, and thus, eucalyptus wood char was investigated as a potential substitute for bone char. This dissertation studied wood char produced from Eucalyptus robusta as an adsorption material to remove fluoride from water, thereby making it safe for consumption. Although the use of eucalyptus wood char alone removed minimal fluoride, when it was amended with aluminum and iron oxides it evidenced much higher fluoride removal capacities. Metal oxides, produced from starting materials such as aluminum sulfate and iron (III) nitrate, were used to amend the wood char. Metal amendments resulted in fluoride removal capacities ranging from 3 to 50 times higher than wood char without amendment. The combination of wood char and metal oxide amendment is synergistic because the wood char provides a matrix with a high specific surface area for the metal oxides to adhere to while the metal oxide amendment increases the electrostatic attraction of the char surface for fluoride. Additionally, wood char was pretreated with oxidizing agents such as hydrogen peroxide and potassium permanganate prior to metal amendment. These pretreated and metal amended chars were found, in most cases, to have increased metal loading rates and, in some cases, higher fluoride removal capacities. This dissertation also looked at ways to improve the adsorption effectiveness of bone char for communities where bone char is an acceptable material for drinking water treatment. Amending bone char with aluminum nitrate showed an increase in fluoride removal at high equilibrium concentrations but not at low equilibrium concentrations close to the WHO recommended value for fluoride (1.5 mg/L). Select fluoride removal materials, including aluminum impregnated wood char, activated alumina, bone char and aluminum amended bone char, were studied in the field using groundwater from a well in a rural Ethiopian community. Field results suggested that the combination of elevated groundwater pH along with competing ions such as sulfate (both common in ground waters of the Ethiopian Rift Valley) affected the fluoride removal capacities of the materials studied, particularly the aluminum impregnated wood char. Finally, this research tested the validity of the Rapid Small Scale Column Tests (RSSCT) principles for bone char adsorbing fluoride from water. These experiments indicated that RSSCT principles are applicable for bone char; use of this approach can result in large time and cost savings to researchers and implementers. Overall, this dissertation provides several conclusions that are practically helpful to researchers in the field and also foundational research on which future studies can build to continue efforts to find sustainable and appropriate fluoride removal technologies

Sustainable use and implementation of bone char as a technology for arsenic and fluoride removal

Arsenic and fluoride are key issues in the global water challenge as they exist above the World Health Organization (WHO) recommended limits of 0.010 mg/L and 1.5 mg/L, respectively, in the natural drinking water sources of many regions of the world. The suitability of using several types of bone char as a sustainable removal technology for arsenic and fluoride in remote areas of developing countries is evaluated. The results suggest that 500˚C is the ideal charring temperature for fish bone char based on removal capacity and aesthetic concerns, such as water discoloration and smell, and that there is no significant competition found when removing fluoride and arsenic simultaneously. Current water projects often fail after one to three years for a variety of reasons. Therefore, implementation strategies will also be discussed

Perceptions of wildlife damage and species conservation: lessons learned from the Utah prairie dog

The Utah prairie dog (Cynomys parvidens), a federally listed threatened species, causes damage to agricultural operations, yet little incentive exists for private landowners to conserve them. Therefore, we surveyed Utah residents to identify stakeholder attitudes regarding prairie dog management. We assessed how perceptions of wildlife damage affect respondent attitudes regarding conservation among agricultural producers, rural residents, and urban residents. Higher levels of perceived wildlife damage were reported for agriculture respondents (79%) than for urban (20%) or rural (45%) respondents. Compensation for damage caused by Utah prairie dogs was supported by those engaged in agricultural production but not by rural or urban respondents. Agricultural producers, rural residents and urban residents all stated a preference for private conservation organizations to fund damage compensation rather than a government agency. Most agricultural respondents (61%) and rural respondents (64%) believed that Utah prairie dogs should be only on public lands. Some agricultural respondents (23%) thought they should be on no land. Attitudes regarding the Utah prairie dog varied, with agricultural producers being the most negative and urban respondents the most positive. The negative attitude of rural residents and agricultural producers probably results from both the damage caused by Utah prairie dogs and land-use restrictions resulting from the species being listed as threatened. Acceptance of Utah prairie dogs by private landowners may be key to the recovery of the species, and our findings suggest that alleviation of damage issues may increase landowner acceptance of conservation measures to protect Utah prairie dogs.n