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Full-Text Articles in Physical Sciences and Mathematics

Palynostratigraphy Of The Umir Formation, Middle Magdalena Valley Basin (Mmvb) Colombia, Carlos Enrique Santos Jan 2012

Palynostratigraphy Of The Umir Formation, Middle Magdalena Valley Basin (Mmvb) Colombia, Carlos Enrique Santos

LSU Master's Theses

The Late Cretaceous Umir Formation in Middle Magdalena Valley Basin (MMVB) was recently acknowledged as a new target. However, there is little known about the regional distribution of the Umir Formation since it is affected by structural complexity and a major regional unconformity. To improve biosteering of the Umir Formation and reduce exploratory risks, a detailed biostratigraphic analysis of the Umir Formation in the MMVB is presented. Eighty samples from four cores drilled in the Central Eastern MMVB were analyzed for palynological content. These cores represent 976.6 meters of the Middle to Upper Umir Formation. The sediment yielded a good …


Impact Of Teaching Style On Student Learning Of Evolution, Laurie Font Jan 2012

Impact Of Teaching Style On Student Learning Of Evolution, Laurie Font

LSU Master's Theses

Natural selection is a topic that is laden with misconceptions. These misconceptions are often not addressed, and students can leave a biology classroom with the same incorrect ideas that they entered with. These misconceptions can be identified and addressed by using the Concept Inventory of Natural Selection (CINS). Furthermore, by teaching using methods that encourage hands-on, inquiry based techniques, students are more apt to reconcile these misconceptions and have a deeper understanding of the natural selection process. The goal of my research was to show a positive correlation between reduction in student misconceptions about natural selection and inquiry based activities. …


The Effects Of Regulatory Uncertainty On The U.S. Acid Rain Program, Narendra Paramanand Jan 2012

The Effects Of Regulatory Uncertainty On The U.S. Acid Rain Program, Narendra Paramanand

LSU Master's Theses

Title IV of the Clean Air Act Amendments of 1990 (CAAA 1990) created the first large scale cap-and-trade program as a means to control acid rain in the United States. The program regulated the emission of sulfur dioxide (SO2) and nitrous oxide (NOx) in the atmosphere—the precursor to acid rain (formerly acid deposition). Economists have long argued for the use of market-based incentive approach as oppose to the traditional command-and-control methods for its ability to be efficient and cost-effective. Title IV went into full effect in 1995 and has been lauded among one of the most successful regulation as it …


Sources Of Salinization Of The Baton Rouge Aquifer System: Southeastern Louisiana, Callie Elizabeth Anderson Jan 2012

Sources Of Salinization Of The Baton Rouge Aquifer System: Southeastern Louisiana, Callie Elizabeth Anderson

LSU Master's Theses

A major environmental and economic problem confronting the Baton Rouge area, southeastern Louisiana, is the progressive salinization of the Baton Rouge aquifer system, an important source of fresh municipal and industrial groundwater. The Baton Rouge fault marks a boundary between fresh groundwaters to the north and predominately brackish waters to the south. Determining the permeability architecture of the fault is an essential component of modeling groundwater flow and saline contamination north of the fault. Understanding the sources and pathways of the saline waters that are migrating into the freshwater sands north of the fault is thus essential in helping to …


Composition And Physiological Characteristics Of The University Lake Ecosystem Phytoplankton Community: Impacts Of Seasonal And Episodic Events, Brianne Elizabeth Norris Jan 2012

Composition And Physiological Characteristics Of The University Lake Ecosystem Phytoplankton Community: Impacts Of Seasonal And Episodic Events, Brianne Elizabeth Norris

LSU Master's Theses

This research determined the changes in phytoplankton community composition in a shallow subtropical lake, influenced by urban surroundings. Specifically this research focused on the effects of seasonal progression and episodic events on the changing inorganic nutrient dynamics and the effects those dynamics had on the phytoplankton community composition and productivity. This research quantified gross primary production and respiration to determine if seasonality or episodic events were acting as forcing functions of the phytoplankton community composition. Water samples were collected weekly at three sites on the lake’s perimeter, as well as following episodic events, to monitor nitrate (NO3), phosphate (PO4-3), ammonium …


Movements And Habitat Use Of Southeastern Blue Sucker Cycleptus Merdionalis In The Lower Pearl River, Devon Charles Oliver Jan 2012

Movements And Habitat Use Of Southeastern Blue Sucker Cycleptus Merdionalis In The Lower Pearl River, Devon Charles Oliver

LSU Master's Theses

Riverine fisheries management programs often do not focus on non-sport and non-commercial fishes, such as catostomids, yet many suckers have become threatened or endangered throughout river systems in the United States because of habitat alterations. In the Pearl River, sedimentation, dam construction, and other hydrologic modifications have negatively impacted habitats used by southeastern blue suckers Cycleptus meridionalis, a species of concern in both Louisiana and Mississippi. The principal objective of this project was to investigate habitat use of likely historically abundant southeastern blue suckers in the lower Pearl River. During electrofishing surveys in 2010 and 2011, we observed no southeastern …


Investigation Of Colored Dissolved Organic Matter And Dissolved Organic Carbon Using Combination Of Ocean Color Data And Numerical Model In The Northern Gulf Of Mexico, Nazanin Chaichitehrani Jan 2012

Investigation Of Colored Dissolved Organic Matter And Dissolved Organic Carbon Using Combination Of Ocean Color Data And Numerical Model In The Northern Gulf Of Mexico, Nazanin Chaichitehrani

LSU Master's Theses

The first part of this thesis includes evaluating and developing empirical band ratio algorithms for the estimation of colored dissolved organic matter (CDOM) and dissolved organic carbon (DOC) for SeaWiFS, MODIS and MERIS ocean color sensors for the northern Gulf of Mexico. For CDOM, matchup comparison between SeaWiFS-derived CDOM absorption coefficients and in situ absorption measurements at 412 nm (aCDOM(412)) were examined using the D’Sa et al. (2006) and the Mannino et al. (2008) algorithms. These reflectance band ratio algorithms were also assessed to retrieve aCDOM(412) from MODIS and MERIS data using the Rrs(488)/Rrs(555) and Rrs(510)/Rrs(560) band ratios, respectively. Since …


Thermal And Pore Pressure History Of The Haynesville Shale In North Louisiana: A Numerical Study Of Hydrocarbon Generation, Overpressure, And Natural Hydraulic Fractures, William C. Torsch Jan 2012

Thermal And Pore Pressure History Of The Haynesville Shale In North Louisiana: A Numerical Study Of Hydrocarbon Generation, Overpressure, And Natural Hydraulic Fractures, William C. Torsch

LSU Master's Theses

New drilling technology has led to a revival of drilling in mature petroleum basins such as the Haynesville Formation in east Texas and north Louisiana. In north Louisiana, the Upper Jurassic (Kimmeridgian) aged Haynesville shale has a basinward SW dip and is located at depths ranging from around 10,500 ft to the northeast and 14,000 ft to the southwest with local minimums at the Sabine and Monroe Uplifts. Formation thickness ranges from 100 to 400 feet. Prolific natural gas production is attributed to relatively high average porosity (8 to 14%) and a high geopressure gradient > 0.9 psi/ft. (Wang and Hammes, …


Integrating Tasks, Technology, And The Common Core Standards In The Algebra Ii Classroom, Beth Perkins Mcinnis Jan 2012

Integrating Tasks, Technology, And The Common Core Standards In The Algebra Ii Classroom, Beth Perkins Mcinnis

LSU Master's Theses

The Common Core State Standards for Mathematics were released in June of 2010. The standards were developed by a team of over 75 teachers and specialist in response to improve math education in the United States through more focused, coherent, rigorous standards to help our students be competitive in the 21st century. As of June 2012, 45 states had adopted the new standards which better coordinate what students at individual grade level should know and be able to do to in order to be college and career ready by grade twelve. With new computer based assessments being developed and set …


Mapping Of The Oil Window In The Eagle Ford Shale Play Of Southwest Texas Using Thermal Modeling And Log Overlay Analysis, Austin Pourciau Cardneaux Jan 2012

Mapping Of The Oil Window In The Eagle Ford Shale Play Of Southwest Texas Using Thermal Modeling And Log Overlay Analysis, Austin Pourciau Cardneaux

LSU Master's Theses

The Eagle Ford formation in South Texas has been an established hydrocarbon play since 2008. The Eagle Ford is considered an unconventional resource because it is a source, reservoir, and seal. Hydraulic fracturing and horizontal drilling have enabled this play. As drilling and production continue the limits of this play are being defined. The area between dry gas and wet gas/condensate has been known for some time since the initial production started in dry gas and moved up-dip. After the oil window was discovered, the contact between wet gas/condensate started to become more defined. Now companies are beginning to delineate …


Evaluation Of Pleistocene To Holocene (Mis 5 To 1) Climatic Changes In Southwestern Black Sea: A Palynological Study Of Dsdp Site 380, Shannon Ferguson Jan 2012

Evaluation Of Pleistocene To Holocene (Mis 5 To 1) Climatic Changes In Southwestern Black Sea: A Palynological Study Of Dsdp Site 380, Shannon Ferguson

LSU Master's Theses

Site 380 of the Deep Sea Drilling Program [DSDP] is located in the southwestern region of the Black Sea (42°05.94’, 29°36.82’E). The location of this site is important due to its proximity to the narrow Bosphorus strait, the only present-day connection between the Black Sea and the Aegean Sea. Drops in eustatic sea level during extensive Pleistocene glacial episodes disconnected the Black Sea from the Aegean Sea at the Bosphorus strait, creating a change from brackish to freshwater within the Black Sea during these intervals. Organic-walled phytoplankton (dinoflagellate cysts, acritarchs, and fresh-water algae) are investigated to better constrain these glacio-eustatic …


Habitat- And Region-Specific Reproductive Biology Of Female Red Snapper (Lutjanus Campechanus) In The Gulf Of Mexico, Dannielle Helen Kulaw Jan 2012

Habitat- And Region-Specific Reproductive Biology Of Female Red Snapper (Lutjanus Campechanus) In The Gulf Of Mexico, Dannielle Helen Kulaw

LSU Master's Theses

This study compares reproductive biology estimates of female red snapper among three habitat types (natural shelf-edge banks, standing petroleum platforms and toppled petroleum platforms) and among six regions in the Gulf of Mexico (central Florida, northwest Florida, Alabama, Louisiana, north Texas and south Texas). In both studies, batch fecundity and spawning frequency increased with length, weight and age, and batch fecundity was best correlated with maternal length. Gulf-wide, 75% maturity was achieved by age-3 and 100% maturity was reached by age-8. Sizes- and ages-at-maturity differed among habitat types and regions. Females from natural habitat reached 50% maturity the slowest (age-5, …


Proton Dose Calculations In Homogeneous Media, John Wesley Chapman, Jr. Jan 2012

Proton Dose Calculations In Homogeneous Media, John Wesley Chapman, Jr.

LSU Master's Theses

In this study, a proton pencil beam dose calculation algorithm was developed for a parallel, monoenergetic beam incident on a homogeneous water phantom. Fermi-Eyges theory (Eyges 1948) was used to transport pencil beams, and the characteristic width of elastic scatter events was modeled using the differential Moliere scattering power (Gottschalk 2010). The incorporation of this scattering power formalism allowed our model to account for multiple Coulomb scattering, single scattering, plural scattering, and rigorously accounted for material effects on scatter. Nonelastic nuclear interactions were incorporated into an additional pencil beam model. The attenuation of primary fluence due to nuclear events was …


Artificial Oyster Reefs In The Northern Gulf Of Mexico: Management, Material, And Faunal Effects, Jessica Nicole Furlong Jan 2012

Artificial Oyster Reefs In The Northern Gulf Of Mexico: Management, Material, And Faunal Effects, Jessica Nicole Furlong

LSU Master's Theses

Artificial oyster reefs seek to restore reef ecosystem services, such as water filtration, shoreline protection, and habitat for nekton. This study established three objectives to address the dispersed nature of artificial reef information in the Gulf of Mexico (GoM) and lack of post-construction monitoring assessments. First, to document the extent of activities in the GoM, we developed a database of all inshore artificial oyster reefs created for restoration purposes. Of the 422 reefs in the resultant database, a third or less provided records of entities involved (27%), restoration goals (24%), area (20%), monitoring efforts (15%), relief (9%), and costs (8%). …


Depositional Environments Of Upper Meiocene Through Pleistocene Siliciclastic Sediments, Baton Rouge Aquifer System, Southeastern Louisiana, Elizabeth Laurel Chamberlain Jan 2012

Depositional Environments Of Upper Meiocene Through Pleistocene Siliciclastic Sediments, Baton Rouge Aquifer System, Southeastern Louisiana, Elizabeth Laurel Chamberlain

LSU Master's Theses

Saltwater encroachment northward into freshwater sands of the Baton Rouge aquifer system, southeast Louisiana, poses a serious environmental threat to the metropolitan water source. The aquifer consists of a 0.6 mile-thick succession of interbedded, unconsolidated south-dipping siliciclastic sandy units and confining mudstones dating from the Upper Miocene through the Pleistocene. The study area is crosscut by the Baton Rouge fault, a west-east trending listric fault that serves as a leaky barrier to saltwater intrusion from the south. A better understanding of the connectivity, morphology and depositional setting of this aquifer system and hydraulic properties of the Baton Rouge fault is …


Sediment Flux & Fate For A Large-Scale Diversion: The 2011 Mississippi River Flood, The Bonnet Carré Spillway, And The Implications For Coastal Restoration In South Louisiana, Jeffrey Bryant Fabre Jan 2012

Sediment Flux & Fate For A Large-Scale Diversion: The 2011 Mississippi River Flood, The Bonnet Carré Spillway, And The Implications For Coastal Restoration In South Louisiana, Jeffrey Bryant Fabre

LSU Master's Theses

Dams and hardened levees built by European settlers in the last two centuries have degraded or stopped the cyclic sedimentation patterns that built the Mississippi River Delta Plain over the past 7,000-8,000 years. Man-made diversions of sediment-laden river water along the lower Mississippi, operated during high water periods, are being considered as a primary mechanism for combating the land loss induced by rising sea-level and these modern controls. To date, no study has documented the sediment-delivery potential of a large man-made river diversion during a single high water event. In the spring of 2011, historic flooding on the Mississippi River …


Variations In Pore Water Salinities Above And Below Allochthonous Salt Sheets In The Deepwater Gulf Of Mexico: Implications For Mechanisms Of Solute Transport, Miles Alexander Mccammon Jan 2012

Variations In Pore Water Salinities Above And Below Allochthonous Salt Sheets In The Deepwater Gulf Of Mexico: Implications For Mechanisms Of Solute Transport, Miles Alexander Mccammon

LSU Master's Theses

Spatial variations in salinity of pore waters in marine sediments provide useful information on processes and rates of subseafloor fluid flow and solute transport, particularly if there are evaporites in the section. Pore water salinities were determined for 18 drill holes which penetrated allochthonous salt bodies in 12 widely-scattered protraction blocks on the Louisiana offshore continental shelf and slope. Salinities were calculated from Log ASCII Standard-Logging While Drilling (LAS-LWD) logs using the Revil et al. (1998) dual-conductivity technique. The sites represent a wide range of field settings. Water depths range from 30 to 1990 m, depths to the top of …


Soil Accretion And Organic Carbon Accumulation In The Tidal Salt Marshes Of The Liaohe Delta, China, Nicholas Lawrence Yuknis Jan 2012

Soil Accretion And Organic Carbon Accumulation In The Tidal Salt Marshes Of The Liaohe Delta, China, Nicholas Lawrence Yuknis

LSU Master's Theses

Wetlands provide a multitude of functions to people and ecosystems and because of this, maintaining or increasing wetland area is important. Wetlands can be significant carbon sinks because of the relatively high primary productivity and slow decomposition of organic matter in these systems and can thus impact the global carbon cycle and potentially climate change. The marshes of the Liaohe Delta are the largest in Liaoning Province; however, very little research has been done in this area to determine the rate of accretion and organic carbon sequestration in the salt marshes there. By using Cs-137 and Pb-210 dating techniques and …


Pretesting In Science: Effect On Unit Test Scores, Mary Catherine Johnson Jan 2012

Pretesting In Science: Effect On Unit Test Scores, Mary Catherine Johnson

LSU Master's Theses

ABSTRACT This study examines the effect that pretesting has on unit test scores in a high school Biology I classroom. The experimental classes were given a pretest before four units of curriculum and then taught the concepts of these units with a traditional lecture based methodology. Their unit test scores were compared to a control class that did not take pretests before the units. In addition, the End of Course (EOC) test scores of the control and experimental classes were compared to determine if pretesting improved transfer of knowledge to a different type of test. Pretesting did not cause a …


Mathematical Modeling In The High School Classroom, Selena Oswalt Jan 2012

Mathematical Modeling In The High School Classroom, Selena Oswalt

LSU Master's Theses

Mathematical modeling is the procedure whereby students apply mathematical concepts learned in class to new and unfamiliar situations. A modeling task is a mathematically-rich problem that engages students in mathematical thinking, drawing upon their previously learned knowledge and supporting their understanding of the mathematical concepts currently being covered. Modeling requires students to assign meaning to the mathematical concepts and to extend the concepts beyond rote learning. In order for students to be successful in a classroom that is centered around the idea of mathematical modeling, the students must be taught how to collaborate with other students, persevere through challenging problems, …


A High-Resolution Palynological Analysis Of The St. Stephens Quarry, Alabama: Locating The Eocene-Oligocene Boundary And Characterizing The Environmental Changes Across The Margin, Kevin Jensen Jan 2012

A High-Resolution Palynological Analysis Of The St. Stephens Quarry, Alabama: Locating The Eocene-Oligocene Boundary And Characterizing The Environmental Changes Across The Margin, Kevin Jensen

LSU Master's Theses

The Eocene-Oligocene (E-O) transition is a key interval in geological history because it marks a major change in Earth’s climate and because these strata are also popular oil targets in the Gulf Coast. E-O sequences in Alabama are stratigraphically complex. The St. Stephens Quarry (SSQ) in Alabama is one of the few accessible quarries along the Gulf Coast where the E-O boundary is visible in outcrop. Despite the abundance of research projects conducted in the SSQ, many controversies still surround the E-O boundary placement and correlation to the Global Stratotype in the Massignano section in Italy that is based on …


A 2-D, Variable-Density Numerical Model Of Subsurface Fluid Flow Through The Edwards Aquifer, New Braunfels, Tx: Mechanisms Inhibiting Flow Across The Freshwater/Saline-Water Interface, Scott Ryan Tipple Jan 2012

A 2-D, Variable-Density Numerical Model Of Subsurface Fluid Flow Through The Edwards Aquifer, New Braunfels, Tx: Mechanisms Inhibiting Flow Across The Freshwater/Saline-Water Interface, Scott Ryan Tipple

LSU Master's Theses

The Edwards aquifer in south-central Texas, U.S., composed of faulted carbonate bedrock, contains freshwater and saline water. In aquifers that are used as a source of drinking water and that contain fresh and saline waters, saline-water intrusion can result in degradation of water quality. Yet, in the Edwards aquifer, limited saline-water intrusion has occurred. The questions addressed are “Why is the saline-water intrusion less than expected,” and “Is there a trigger that will result in saline-water intrusion into the freshwater reservoir?” Three hypotheses were tested. One: an extremely saline water density might prevent mixing across the interface. Two: faults could …


Effect Of Instructional Methodologies On Student Achievement Modeling Instruction Vs. Traditional Instruction, Jacqueline Grace Barker Jan 2012

Effect Of Instructional Methodologies On Student Achievement Modeling Instruction Vs. Traditional Instruction, Jacqueline Grace Barker

LSU Master's Theses

ABSTRACT Different teaching styles can impact student learning in many ways. The purpose of this study was to determine the effectiveness of Modeling Instruction on student achievement in a high school Chemistry course. Different tests were used to compare the data at the beginning of a school year and at the end of the school year. The tests used were to determine gains in chemistry content knowledge, abilities to reason scientifically, and attitudes about learning chemistry. The control group was taught by traditional instruction through the use of lecture, note-taking, and textbook guided assignments. The experimental group was taught by …


Using A Collaborative Inquiry Process And Data To Affect Curriculum In An Independent School, Sheri Lyn Pastor Goings Jan 2012

Using A Collaborative Inquiry Process And Data To Affect Curriculum In An Independent School, Sheri Lyn Pastor Goings

LSU Master's Theses

Literature clearly supports the use of data to support and drive school policy. Data can be immensely informative; however test scores are not the sole indicator of school effectiveness. To successfully implement a plan for data use, it is imperative to a provide climate of teacher buy-in and collaboration. Multiple sources of data should be considered collectively prior to making any judgment(s) about students, teachers, curriculum, or schools. Data use for effective decision-making is an on-going process that requires strategic planning and a long-term commitment. Over the past year, I have led the math department through a modified version of …


Nitrogen Biogeochemistry In A Restored Mississippi River Delta: A Modeling Approach, Benjamin Lee Branoff Jan 2012

Nitrogen Biogeochemistry In A Restored Mississippi River Delta: A Modeling Approach, Benjamin Lee Branoff

LSU Master's Theses

There is evidence that significant reductions (about 50%) in surface water nitrate concentrations within coastal deltaic wetlands receiving diverted Mississippi River water can be contributed to denitrification. Yet there is also contrasting evidence that other processes could be responsible for this nitrate reduction. As Louisiana plans the implementation of major Mississippi River sediment diversions, a thorough understanding of nitrogen dynamics is necessary to reduce risks of coastal eutrophication and offshore hypoxia. A mechanistic numerical computer model has been developed to simulate nitrogen biogeochemistry within the wetlands of the prograding Wax Lake Delta. This model is calibrated to observed fluxes within …


U-Pb Geochronology Of Detrital Zircon In Quartzites Of The Sawtooth Metamorphic Complex, Sawtooth Range, Idaho, Usa, Philip Gerard Bergeron Jan 2012

U-Pb Geochronology Of Detrital Zircon In Quartzites Of The Sawtooth Metamorphic Complex, Sawtooth Range, Idaho, Usa, Philip Gerard Bergeron

LSU Master's Theses

In southwest Laurentia, the Paleoproterozoic Selway terrane has been proposed to extend as basement from the Wyoming Province to the Proterozoic rifted margin of Laurentia primarily based on limited exposures. The Sawtooth Metamorphic Complex (SMC), Idaho, a series of high-grade metasupracrustal rocks lies within the proposed region of the Selway terrane and may represent remnants of this terrane. Alternatively, it may represent another basement terrane of cratonic North America. To test the hypothesis that the SMC belongs to the Selway terrane, detrital zircon U/Pb ages of five quartzite samples were analyzed by LA-ICP-MS to establish age, possible provenance, and age …


The Context Of Public Acceptance Of Hydraulic Fracturing: Is Louisiana Unique?, Crawford White Jan 2012

The Context Of Public Acceptance Of Hydraulic Fracturing: Is Louisiana Unique?, Crawford White

LSU Master's Theses

Hydraulic fracturing has received increased attention over the past decade. The rapid adoption of this technique coupled with accurate directional horizontal drilling has unlocked several US shale formations. Amid the possibility of 100% domestically sourced natural gas, public perception varies and opponents question the long-term risks and repercussions of the technique. This thesis will provide context to some of the variation seen in the public perception of hydraulic fracturing among three states: Louisiana, Pennsylvania, and Texas. Two surveys of Louisiana stakeholders were conducted in order to rank the state in terms of acceptance amongst previously conducted surveys of its two …


Opportunistic Lookahead Routing Procedure For Delay Tolerant Networks, Priyanka Rotti Jan 2012

Opportunistic Lookahead Routing Procedure For Delay Tolerant Networks, Priyanka Rotti

LSU Master's Theses

Delay Tolerant Networks are wireless networks that have sporadic network connectivity, thus rendering the existence of instantaneous end-to-end paths from a source to a destination difficult or impossible. Hence, in such networks, message delivery relies heavily on the store-and-forward paradigm to route messages. However, limited knowledge of the contact times between the nodes poses a big challenge to effective forwarding of messages. In this thesis, we discuss several aspects of routing in DTNs and present one algorithm and three variants for addressing the routing problem in DTNs: (i) the Look-ahead Protocol, in which the forwarding decision at each node to …


Writing In Geometry With The Common Core State Standards: Developing Mathematical Thinkers, Yvonne Mariki Chimwaza Jan 2012

Writing In Geometry With The Common Core State Standards: Developing Mathematical Thinkers, Yvonne Mariki Chimwaza

LSU Master's Theses

The newly released Common Core State Standards (CCSS) were adopted with the goal in mind that in the future our students will leave high school ready and better prepared for college and careers. In particular, the CCSS insists that a faithful implementation of the eight Standard of Mathematical Practices will lead to a generation of mathematical thinkers who have learned how to read, write, model, reason, and solve problems in mathematical terms. Unfortunately, at present, my students and others do not know how to write and reason mathematically. By way of this thesis, I searched for ways to help forty-five …


Evaluation Of A Proton Pencil Bean Algorithm For Dose Calculations In Heterogenous Media, Nels C. Knutson Jan 2012

Evaluation Of A Proton Pencil Bean Algorithm For Dose Calculations In Heterogenous Media, Nels C. Knutson

LSU Master's Theses

Purpose: To develop an improved nuclear halo dose model of a pencil beam algorithm (PBA) for dose calculation of proton beams in heterogeneous media. Methods: The proton PBA consisted of a central axis term and an off axis term. The central axis term was determined from a central axis depth dose profile of a Monte Carlo simulated proton beam in water and was scaled by a mass stopping power ratio to account for other materials. The off axis term was determined from Fermi-Eyges scattering theory with material-dependent scattering powers to calculate the lateral spread of the proton beam in heterogeneous …