No description available.

No description available.

Electrochemical Ion Exchange (EIX) was studied to determine the viability of the process for treatment of metal bearing effluents containing Cu, Zn and Ni. Other metals used during the investigation were Na and Cs. The EIX process was examined at the laboratory scale and later in a pilot plant. Process performance and cell design were evaluated both in absorption and regeneration cycles. A mathematical representation of the system was developed based on the Nemst-Planck equation. Zirconium phosphate, Purolite S930 , Purolite S950 and Purolite PrAOH were the ion exchangers used during the study. The EIX cell was made of two perspex blocks, each 490 mm by 125 mm and 20 mm thick. Each block contained a half cell made up of an EIX electrode and a counter electrode on either side of a heterogeneous ion exchange membrane with dimensions of 280 mm by 63 mrn by 5 mm. The EIX electrode consisted of a platinised titanium mesh, acting as a current feeder, embedded in the membrane. The counter electrode was a platinised titanium mesh placed on the opposite side to the current feeder. The process was operated by applying a potential across the membrane.

No description available.

No description available.

Thesis advisor: Noah P. Snyder / The Souhegan River is a tributary of the Merrimack River that drains a 443 km<super>2</super> watershed in southern New Hampshire. The lowermost barrier on the Souhegan River, the Merrimack Village Dam (MVD), was demolished and removed in August and September 2008. The modern MVD impoundment contained at least 62,000 m<super>3</super> of sediment, mostly sand. Analysis of topographic and historical maps, and photographs suggests that approximately twice the area of what is now the modern impoundment has been affected by over 200 years of damming at the site. I use repeat surveys of cross sections and the river longitudinal profile, and sediment samples, to document the response of the Souhegan River to the MVD removal. A base level drop of 3.9 m caused immediate incision of the sand-sized sediment and channel widening. The impoundment later segmented into a non-alluvial, bedrock and boulder controlled reach; and a quasi-alluvial sand and gravel reach with erosion and deposition modulated by the presence of vegetation on the channel banks. One year after the removal, the Souhegan River has excavated 38,100 m<super>3</super> (65%) of the sediment in the modern impoundment. The response of the Souhegan River was rapid and the channel and floodplain continue to evolve toward a quasi-equilibrium configuration. Continued response will be substantially influenced by the establishment of vegetation within the former impoundment and the magnitude and frequency of high discharge events. / Thesis (MS) — Boston College, 2010. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Geology and Geophysics.

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Thesis advisor: Noah P. Snyder / Dam removal is typically used to restore fish passage, natural flow regimes, and sediment transport in streams. However, dam removal also impacts the riparian vegetation, a change that can have wider effects throughout the ecosystem. Quantifying vegetation change requires a multi-year record to document pre-removal communities and both the immediate and delayed responses. In this study, vegetation change was assessed at the Merrimack Village Dam on the Souhegan River in Merrimack, NH, which was removed in August 2008. The removal caused a ~3 meter drop in water level and rapid erosion of impounded sediment, with ~50% removed in the first three months. The vegetation was sampled using plots at specific intervals along 7 monumented transects that were perpendicular to the channel or adjacent wetland. Tree, shrub, and herbaceous communities were assessed using species percent areal coverage techniques in July 2007, 2009, 2014 and 2015. Change over time was quantified using Analysis of Similarity (ANOSIM) on the Bray-Curtis dissimilarity matrix. As expected, vegetation communities in control plots upstream of the impoundment did not show significant change during the study period. Tree and shrub communities adjacent to the impoundment also did not show significant change. All herbaceous communities adjacent to the impoundment changed significantly (p < 0.05). The herbaceous plots closest to the channel changed to bare sand in 2009 due to erosion in the former impoundment, but by 2014 the riparian fringe community seen in 2007 had re-established and expanded in this area, but at a lower elevation. Between 2007 and 2014, the wetland herbaceous community changed from aquatic species to a stable terrestrial community that persisted without significant change in 2015. From 2007 to 2014, the vegetation community on a mid-channel island of impoundment sand changed from a community with ~50% invasive reed canary grass to a ~98% community of invasive black swallowwort, a species not recorded at the site pre-removal. The vegetation response was greatest in areas with largest geomorphic and hydrologic change, such as along the channel margin where erosion and bank slumping created an unstable scarp or on the mid-channel island and off-channel wetland strongly impacted by the lowered water table. However, large unvegetated areas never persisted nor did the areal coverage of invasive species expand: two common concerns of dam removals. / Thesis (BS) — Boston College, 2016. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Scholar of the College. / Discipline: Earth and Environmental Sciences.

Thesis (LL. M.)--Judge Advocate General's School, U.S. Army, 1961. / "April 1961." Typescript. Includes bibliographical references (leaf 74). Also issued in microfiche.

Ashe Juniper (Juniperus ashei) is native to the Edwards Plateau in central Texas. In the past 150 years, however, this species has rapidly increased in abundance within its range. Reduced fire frequency and increased livestock grazing, are two factors attributed to the rapid rate of juniper encroachment. While the losses associated with brush encroachment are recognized, many ranchers lack the funds necessary to implement management practices to reduce juniper densities on their property. The high cost associated with clearing brush has led to the creation of cost-share programs, which help offset the expenses incurred by participating landowners. The Leon River Restoration Project (LRRP), implemented on private lands within Coryell and Hamilton Counties, Texas, is one such cost-share program. Funding for the LRRP is received through non-programmatic sources, in the form of grants, from various state and federal organizations and agencies. The Natural Resources Conservation Service (NRCS) provides a second source of funding through the Environmental Quality Incentives Program (EQIP). Participants contracted through LRRP funds receive 85% cost-share benefits, up to a maximum of $15,000. Landowners participating in the LRRP under EQIP funds receive 50% cost-share incentives, up to a maximum of $250,000. The purpose of this study was to record changes that occurred on land enrolled in the LRRP, following juniper removal, and the economic benefits recognized by this work. Thirty landowners scheduled to participate in the LRRP were interviewed in 2003, prior to juniper control work. In 2006, 23 of the original 30 landowners participated in a second interview, following their completion of brush removal work. Changes attributed to juniper removal were recorded during these post-clearing interviews. Stocking rate changes were used as the basis for measuring economic benefits recognized by the clearing efforts. Changes in hunting or grazing lease rates resulting from juniper clearing were also used to monitor economic benefits of the brushwork. A second component of the study tested for differences in landowner satisfaction between LRRP participants enrolled under LRRP funds, and those contracted under EQIP funds. Importanceperformance matrixes were created to display satisfaction differences.