Physical Sciences and Mathematics Commons^™

The Influence Of Hydrogeomorphology, Soil Redox Conditions, And Salinity On The Spatial Zoning Of Saltgrass, Salt Rush, And Cattails In Scotts Creek Marsh, Swanton Pacific Ranch, Ca, Mark D. Gormley

Master's Theses

Scotts Creek Marsh (SCM) is a small coastal wetland ecosystem in Davenport, CA. The vegetation of SCM is dominated by three halophytic zones comprised of saltgrass, salt rush, cattails. The objectives of the study were (i) to investigate the variables that influence the zoning of the three dominant halophyte communities in SCM and (ii) to the test the effectiveness of Indicator of Reduction in Soil (IRIS) tubes to indicate the reduction of S. The study examined the following parameters from April 6 to July 21, 2013: (i) the HGM of Scotts Creek Marsh, (ii) soil oxidation and reduction (redox) conditions, …

Synthesis, Characterization And Application Of Two-Dimensional Layered Metal Hydroxides For Environmental Remediation Purposes, Cleopas Machingauta

Dissertations (1934 -)

Two-dimensional layered nano composites, which include layered double hydroxides (LDHs), hydroxy double salts (HDSs) and layered hydroxide salts (LHSs) are able to intercalate different molecular species within their gallery space. These materials have a tunable structural composition which has made them applicable as fire retardants, adsorbents, catalysts, catalyst support materials, and ion exchangers. Thermal treatment of these materials results in destruction of the layers and formation of mixed metal oxides (MMOs) and spinels. MMOs have the ability to adsorb anions from solution and may also regenerate layered structures through a phenomenon known as “memory effect”. Zinc-nickel hydroxy nitrate was used …

Molecular Characteristics Of The Water Soluable Organic Matter In Size Resolved Aerosols Collected Over The North Atlantic Ocean, Sarah Catherine Gurganus

Chemistry & Biochemistry Theses & Dissertations

Aerosol particulate matter is acknowledged to have effects on health and the environment and further investigation into the molecular characteristics of aerosols is necessary in order to fully understand the potential links between the molecular characteristics and the impacts that these particles have on health and the environment. Aerosols are often discussed with reference to their size because particles of different sizes can often be associated with different primary sources. This study presents a molecular-level chemical characterization of the water soluble organic matter fraction of 17 aerosol impactor samples representing 3 air mass influences (North American, North African, and marine) …

Sustainable Development Of Tajikistan: Perspectives For Tajik Aluminum Company (Talco), Tahmina Azizova

Capstone Collection

Energy efficiency is one the most pressing objectives of the XXI century. Energy efficiency is an intrinsic part of sustainable development of any country. But it is especially crucial for country like Tajikistan, which has an inefficient energy use pattern as a result of the legacy of Soviet era. Energy resources required for economic development can be obtained not only through increased extraction of raw materials, but also through improved energy efficiency at the demand side. Tajikistan imports about 35 percent of its energy needs, which makes the country extremely energy-dependent. That leads to an obvious inference that for Tajikistan …

Probing The Low Temperature Oxidation Of Furanic Biofuels, 2-Methyltetrahydrofuran And 2,5-Dimethylfuran, Utilizing Orthogonal Time-Of-Flight Mass Spectrometry Coupled To Synchrotron Radiation, Matthew Mcmanus

Master's Theses

Concern over natural resources and global climate shifts has increased the focus of sourcing transportation fuels from depleting oil wells to regenerative, biological based solutions. One avenue of biologically sourced fuel involves the extraction of C5 and C6 sugars from the woody, fibrous, and inedible plant materials, otherwise known as lignocellulosic biomass. These cellulosic sugars can be converted to target biofuels and biofuel additives like the furanic compounds, 2,5-dimethylfuran and 2-methylfuran. In this thesis, the low temperature oxidation of two compounds, 2,5-dimethylfuran and 2-methylfuran, are explored. These reactions were conducted at the Advanced Light Source in Berkeley, CA and used …

Quorum Sensing And Metabolism In Marine Environments, Amanda May

Doctoral Dissertations

Quorum sensing (QS) is a phenomenon that allows bacteria to communicate with each other. Small molecules known as autoinducers are synthesized and released by bacteria, and once enough members of the community are around to ensure survival, i.e. quorum, a phenotype, e.g. bioluminescence, is expressed. There are two types of QS molecules, intra- and inter-species.

S-4,5-Dihydroxy-2,3-pentanedione (DPD) is a byproduct of the activated methyl cycle which recycles methionine. This has led to the discussion as to whether DPD is a metabolic byproduct or is the interspecies signal as proposed previously. The detection and quantitation of DPD however, has not …

Adsorption Of Antimony By Birnessite And The Impact Of Antimony On The Electrostatic Surface Properties Of Variable-Charge Soil Minerals, Kalyn Alaine Vergeer

Masters Theses

Antimony (Sb) is a toxin that can be found in high concentrations in the soil due to anthropogenic sources. Antimony exists in soil as Sb(V) in the monovalent antimonate hydroxyanion. The adsorption mechanisms of Sb(V) are not well-characterized. The objective of this study was to further elucidate Sb(V) adsorption mechanisms by examining the impact of adsorption on surface charging characteristics of gibbsite, goethite, birnessite, and kaolinite. Also examined was Sb(V), SO₄ [sulfate], and PO₄ [phosphate] adsorption by birnessite. Electrophoretic mobility and potentiometric titrations were employed to examine the ζ-potential [zeta-potential] and net proton surface charge density as a …

Cycling Of Molecular Hydrogen In Subarctic Sweden, Victoria Ward

Honors Theses and Capstones

No abstract provided.

Transformations, Bioavailability And Toxicity Of Manufactured Zno Nanomaterials In Wastewter, Sewwandi Rathnayake

Theses and Dissertations--Plant and Soil Sciences

In order to properly evaluate the ecological and human health risks of ZnO Manufactured nanomaterials (MNMs) released to the environment, it is critical to understand the likely transformation products in the wastewater treatment process and in soils receiving biosolids. To address this critical knowledge gap, we examined the transformation reactions of 30 nm ZnO MNMs in single component and multi-component systems, with phosphate and natural organic matter (NOM). We also assessed the influence of nano ZnO transformation on the bioavailability, and toxicity of ZnO transformation products to Triticum aestivum. The data revealed that ZnO MNMs react with phosphate at …

Use Of Sweet Potato To Develop A Medium For Cultivation Of Lactic Acid Bacteria, Saeed A. Hayek

Dissertations

This study investigated the use of sweet potatoes (Ipomoea batatas) as a basic component to develop a medium for cultivation of lactic acid bacteria (LAB). Extract from baked sweet potatoes was used to form a sweet potato medium (SPM). SPM was supplemented with 4 g/L of each nitrogen source (beef extract, yeast extract, and proteose peptone #3). Lactobacilli MRS was used as a control medium. Ten LAB strains were used to determine the suitability of SPM serving the growth of LAB. Our results showed no significant (p < 0.05) differences in the optical density, maximum specific growth rates, and bacterial populations between MRS and SPM. SPM also maintained higher pH values throughout the incubation period compared to that in MRS. The cost of SPM was 47% less than the cost of MRS. Further step was taken to determine the suitability of SPM serving LAB enzymatic activity. LAB strains growing in SPM showed relatively higher β-glucosidases, acid phosphatase, and phytase activities and lower a-glucosidase compared to that in MRS. Strains of L. reuteri showed the …

My Experience Exploring The Effects Of Lead (Pb +2) Toxicity In Drosophila Melanogaster Using Sociability Interaction Testing And Microarrays At The University Of Puerto Rico-Rio Piedras In San Juan, Puerto Rico, Charlton Diaz

Honors Theses

Lead is an environmental contaminant widely dispersed throughout the world. Exposure to lead causes neurological damage in humans and may be linked to neurodevelopmental pathologies such as attention deficit hyperactivity disorder, antisocial behavior, and autistic spectrum disorders (ASD). Drosophila melanogaster (fruit flies) have been used to understand the behavioral, synaptic, and molecular changes that occur after developmental exposure to lead and to study ASD-associated pathology. Flies were exposed through the mother and until eclosion to either a lead-laced medium or a control corn-based medium and were isolated until the beginning for the behavioral studies. Sociability testing was done using a …

Treatment Of Reverse Osmosis Brine With Advanced Oxidative Processes For Enhanced Phosphorus Removal, Petrease Patton

Theses and Dissertations (Comprehensive)

Current regulations for sensitive receiving waters are approaching the limit of technology for phosphorus removal and improved methods are required. Existing methods target removal of the orthophosphate form of phosphorus, but to achieve low effluent limits other non-reactive (NRP) forms, such as condensed phosphate and organic phosphorus, must be removed as well. This could be accomplished by developing a quaternary step in wastewater treatment that utilizes reverse osmosis (RO) followed by advanced oxidation processes (AOP) on the produced brine (RO concentrate). The objective during advanced treatment is to convert NRP in the brine to reactive phosphorus for removal by traditional …

Determination Of Copper Speciation, Bioavailability And Toxicity In Saltwater Environments, Tara N. Tait

Theses and Dissertations (Comprehensive)

The speciation of copper plays a strong role in determining bioavailability and toxicity upon copper exposure in marine environments. Specifically, natural organic matter (NOM) can complex with copper, influencing speciation and decreasing bioavailability. The aim of this research was to determine accurate copper speciation values using literature and new techniques and applying the techniques that reflect the most accurate speciation values to investigate the influence of NOM quantity and quality on copper speciation and toxicity. The results from this study will have implications on the development of a marine Biotic Ligand Model (BLM). Free copper was measured using a flow-through …