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Affecting Martensitic Transformation And Residual Stress Development Through Stress Superposition And Incremental Forming, Elizabeth Marie Mamros

Doctoral Dissertations

Stress superposition is defined as the incorporation of additional stresses into an existing manufacturing process during a single operation. In this thesis, experiments, simulations, and modeling of stress superposition in sheet metal deformation were investigated. Stress superposition can be used in manufacturing to reduce forming forces, increase material formability, and tailor the final part properties of products according to their intended applications, creating so-called functionally graded materials. Austenitic stainless steels (SS) were the focus due to their susceptibility to strain-induced phase transformation from austenite to martensite based on the stress state applied. In the first chapter, a novel cruciform specimen …

Robust Behavior Cloning For Multi-Step Sequential Task Learning By Robots, Mostafa Abdallah Mohamed Hussein

Doctoral Dissertations

This research is about learning high-level policies of multi-step sequential (MSS) tasks – such as activities of daily living – from demonstrations in a sample efficient manner. This research does not assume access to a simulator or an expert to provide more demonstrations. Learning a task policy in such a setting using state-of-the-art end-to-end approaches is sample inefficient due to a reliance on deep learning frameworks, which are known to require a large amount of data. Besides that, most imitation learning frameworks in robotics assume that a domain expert’s demonstration always contains a correct way of doing the task. Despite …

Physiological And Biochemical Analysis Of The Nitrogen Metabolism And Lead Treatment In Hybrid Poplar Clone Nm6 (Populus Nigra L. X P. Maximowiczii A. Henry), Medini Weerasinghe

Doctoral Dissertations

ABSTRACTThe first objective of my Ph.D. research was focused on understanding the reasoning for changes observed in the physiology and metabolism of the poplar plants in response to foliar application of nitrogen. Increased use of nitrogen in the soil in agriculture, in the form of nitrogen fertilizers, has helped to promote high-yield agriculture over the past decades. However, a large fraction of nitrogen applied to croplands in the form of fertilizer and manure ends up entering the freshwater system causing degradation of the water quality and eutrophication of groundwater, rivers, lakes, and coastal and marine ecosystems. Chemical fertilization is also …

An Analysis Of Fine-Scale Structure Within Ion Upwelling Processes, Niharika Godbole

Doctoral Dissertations

This dissertation showcases the projects that I have been involved with since I joined the Magnetosphere-Ionosphere Research Laboratory (MIRL) at the University of New Hampshire (UNH) in August 2017, under the guidance of my research advisor, Marc Lessard. Chapters 1, 2, and 3 of this dissertation are intended to provide the science background necessary to discuss the research projects presented in Chapters 4, 5, and 6 respectively.

The system that this dissertation addresses is complex and interconnected. In the most general sense, the Sun interacts with the Earth through the highly conductive, magnetized plasma that it emits, which directly shapes …

Building An Open Source Toolkit For Integrating Multiple Datasets For Seafloor Characterization And Habitat Mapping, Massimo Di Stefano

Doctoral Dissertations

Characterizing and mapping the seafloor and its features requires collecting and analyzing datasets of varied types and scales. Remotely-sensed data can increase our understanding of seafloor processes by providing insight into seabed geomorphology, substrate characteristics, etc., over large areas. Collecting direct observations or physical samples of the seafloor, also known as ground-truth data, holds the key to interpreting and validating remote sensing data. In this thesis, the case is made that by concurrently analyzing some or all of these datasets, knowledge about seafloor processes is gained more efficiently and I develop tools for seafloor habitat mapping.

In Paper I, I …

Securing Approximate Computing Systems, Pruthvy Yellu

Doctoral Dissertations

Approximate Computing (AC) techniques have been leveraged to improve computing performance and energy efficiency with minor degradation in accuracy. Different than conventional computing, AC allows the computation to deviate from the reference or deterministic execution behavior. Thus, AC has emerged as a new paradigm of computing systems, especially for the applications such as image processing, audio recognition, and artificial intelligence. The majority of research efforts on approximate computing focus on new approximation mechanism design and implementation, rather than examining the security vulnerabilities of AC systems. To fill this gap, we first analyze the potential security threats induced by the AC …

Non-Covalent Anchoring Strategies For Hybrid Electrocatalytic Systems, Peiyuan Zhao

Doctoral Dissertations

Global climate change, induced by increasing anthropogenic emission of heat trapping gases, has drawn great attention from scientists in recent decades. Reducing carbon emissions by decreasing the usage of fossil fuels and applying low/no carbon energy sources is a promising solution for a sustainable future. Electrocatalytic proton reduction to form hydrogen, using green electricity is a practical starting point.

Recent examples of heterogenized molecular catalysts have shown promise but stable anchoring to electrode surfaces is still a challenge. Heterogeneous electrocatalysis shows much more stability, but these systems lack the selectivity provided by a molecular system when more challenging reactions are …

Nonlinear System Identification And Motion Control System Design For Uncrewed Underwater Vehicles, Oguzhan Oruc

Doctoral Dissertations

Modeling and control of marine robotics have become a conspicuous research topic in the controlengineering community in the last decade. Remotely operated underwater vehicles (ROVs) are deployed and used in commercial, military, and scientific areas for many different purposes such as inspection and maintenance of submerged infrastructure, underwater surveillance/maritime, security, and ocean floor mapping most of which cannot be achieved effectively by human operators. However, to be able to operate these vehicles, an effective controller must be obtained, and an accurate dynamic mathematical model of the vehicle from which to design the controller is necessary. Although conventional modeling approaches are …

Evaluating Growth Patterns Of Beech Bark Disease Fungal Agents Neonectria Faginata And Neonectria Ditissima Under Different In Vitro Conditions, Santiago Rivera Reyes

Master's Theses and Capstones

The co –occurring fungal species Neonectria ditissima and Neonectria faginata are major canker-forming pathogens in the beech bark disease (BBD) systems which has caused restructuring of forests throughout northeastern North America. The role of nutrients in structuring microbial community interactions has been studied in BBD forests stands but has yet to be fully understood and examined under specific in-vitro conditions. This study aimed to investigate how nitrogen, phosphorus, and temperature levels influence the growth, reproduction, and competitive hierarchies between N. ditissima and N. faginata. We performed in-vitro assays where species were first individually and then jointly grown under different concentrations …

Climate Change Resiliency In Coastal New Hampshire Roads With The Application Of Natural And Nature-Based Features, Lauren Emma Dwyre

Master's Theses and Capstones

Coastal communities rely heavily on their road network for the transportation of goods, services, and people. However, rising sea levels due to climate change are causing many of the communities’ transportation infrastructure to become vulnerable to coastal stressors. Understanding how sea-level rise (SLR) will impact pavement performance and identifying adaptation strategies is vital for making coastal communities more resilient. Natural and Nature-Based Features (NNBF) are becoming increasingly recognized as an adaptation solution to protect coastal communities from SLR-induced stressors and provide ecological and social benefits. This research aims to identify the linkages between storm surge and pavement damage and identify …

Changing Long-Term Spatial Climate Patterns Of The Northeastern U.S., Emily Landry

Master's Theses and Capstones

Climate variables such as temperature, precipitation, and dewpoint are dynamic and important drivers of many ecosystem processes. In the northeastern United States, climate change, including increasing temperatures and changing precipitation regimes, is well documented, yet changes in regional climate patterns have been largely overlooked. A previous study completed a regional climate analysis of the northeastern US using multiple linear regressions that produced coefficients that describe broad-scale spatial climate patterns using monthly climate normals from 1951-1980. Here, we complete a reanalysis of the previous study using the newest monthly climate normals from 1991-2020 to assess how the spatial climate patterns have …

Variable Light Penetration And Chlorophyll Concentrations From A Vertical Profiler In The Gulf Of Maine, With Implications For Remote Sensing And Ecosystem Modeling, Terence W. O'Brien

Master's Theses and Capstones

Variability in light field penetration into the ocean alters both radiant heat flux and oceanic primary production. Both are increasingly important in the context of quantifying biologically-mediated atmospheric carbon fluxes and sea surface temperature increase in a changing climate. Accurate determination of light penetration into the upper ocean depends upon accurate estimates of the depth-resolved water absorption and attenuation properties through the water column, properties that are often assumed homogeneous vertically and slowly variant in time. This thesis explores all-new Gulf of Maine datasets collected using a moored vertical profiler that provides sub-hourly light attenuation profiles with sub-m vertical resolution …

Shoreline Oil Spill Response Knowledge Gaps And Technological Development Opportunities: A Workshop Report, Crrc, Noaa, Bsee

Coastal Response Research Center

The Bureau of Safety and Environmental Enforcement (BSEE) partnered with NOAA’s Office of Response and Restoration (OR&R) and UNH’s Coastal Response Research Center (CRRC) to plan and facilitate an in-person workshop on the NOAA WRC in Seattle, WA. This event entitled “Shoreline Oil Spill Response Knowledge Gaps and Technological Development Opportunities” identified knowledge gaps and opportunities regarding technologies and scientific research associated with oil spill shoreline response. This effort included the exploration of the current state of the science of oil spill research associated with impacts of crude oil to shoreline environments and identified countermeasures and response alternatives that may …

Strawberry Production Guide For The Northeast, Midwest, And Eastern Canada 2nd Edition, Rebecca Sideman, Kaitlyn Orde

UNH Cooperative Extension

This guide is intended as a comprehensive resource for both novice and experienced strawberry growers in northeastern North America. It provides information on all aspects of strawberry culture. The second edition has been updated and revised throughout, and includes expanded and new information on variety selection (Ch. 3), production systems (Ch. 4), harvesting, handling and transportation (Ch. 12), marketing (Ch. 13) and budgeting/economics (Ch. 14). In addition, a new section on diagnosing problems in strawberry plantings has been added (Ch. 15).

Investigation Of Temperature And Deformation Path Effects On Induced Martensite Transformation Of Ss304l During Double-Sided Incremental Forming, Matthew Dana Adams

Master's Theses and Capstones

Incremental sheet forming (ISF) was invented to make sheet metal manufacturing more flexible, enabling rapid prototyping. However, it was initially plagued with inaccurate tolerances. With the advent of double-sided incremental forming (DSIF) more accurate sheet metal parts are capable and thus has received more interest from industry in recent years. In this thesis, the effects of both temperature control, using a vortex tube with compressed shop air, and deformation path, utilizing a reverse, reforming sequence, have on the strain induced γ-austenite to a’-martensite phase transformation in stainless steel 304L (SS304L) during double sided incremental forming were studied on a pyramidal …

Laboratory Techniques For Measurements Of A Dynamic Water Surface, Vivek Anand Bheeroo

Master's Theses and Capstones

The free surface at an air-water interface can provide information regarding bathymetriccomplexities, as well as the subsurface flow. This work covers an exploration of optical techniques that allow for non-intrusive measurements over a wide domain of the free surface. We present a comparison of the performance of two recent advances in light-based optical techniques for free surface measurements, Total Internal Reflection-Deflectometry and Moon- Glade Background Oriented Schlieren, with the more established method of Free-Surface Synthetic Schlieren. We make use of an optical flow algorithm over the more traditional Digital Image Correlation, in order to obtain higher spatial resolution data across …

Habitat Suitability Modeling Long-Term Growth And Healthy Cover Trends Of Staghorn Coral (Acropora Cervicornis) Outplants In The Lower Florida Keys, Glenna Dyson

Master's Theses and Capstones

In the Florida Keys Acropora cervicornis has been targeted for restoration due to its importance as a reef building stony coral. Habitat suitability models have been utilized within restoration ecology to identify potential locations for outplanting. To date, habitat suitability models have used coarse spatial data of large areas throughout the Florida Keys, resulting in recommended outplant sites that restoration groups have financial and logistical limitations to access and regularly monitor, due to being far away. Additionally, outplanting success can vary widely within a limited space, necessitating improved predictive abilities of coral outplant success within a restoration site. With the …

Effects Of Perennial Forage Composition And Harvest Intensity On The Weed Seedbank Community, Lilly E. Hartman

Master's Theses and Capstones

Most arable weeds arise from a resident soil seedbank and are typically controlled with tillage and herbicides, each of which pose sustainability challenges to growers and consumers. However, agronomic management practices that reduce weed seed input to the seedbank and that accelerate mortality of seeds already in the soil could reduce the need for more conventional weed control. Previous research and farmer practice has demonstrated that rotation of annual crops with several years of perennial forage can reduce weed abundance and the need for chemical weed control. In perennial forage systems, crop species and harvest intensity may have important effects …

Evaluation Of A Wave Powered Water Pump Performance By Ocean Field Testing And Wec-Sim Modeling, Chelsea Kimball

Master's Theses and Capstones

A rising demand for macroalgae (or seaweed) has led researchers to seek out methods of increasing macroalgae aquaculture yields. Macroalgae is a food product, and may be used in biofuel, animal feed, and fertilizer. Applying upwelling technology to macroalgae aquaculture has been shown to increase biomass yield. A wave-powered upwelling device (or water pump) generates cold, nutrient-rich water flow to the surface of an aquaculture operation. A wave pump device developed at University of New Hampshire was refurbished and outfitted with instrumentation to determine its performance. Testing in the laboratory on both the device and instrumentation was conducted to prepare …

Laboratory Assessment Of Rapid-Setting Concrete Used For Field Placed Connections In Accelerated Bridge Construction, Spencer William Mckinnon

Master's Theses and Capstones

Accelerated bridge construction (ABC) has become commonplace thanks to its reduced impact and delays on public infrastructure and traffic. While ABC projects enjoy high material quality due to a large fraction of precast and prefabricated elements, connections between these elements must be placed in-situ. Many transportation agencies as well as project sponsors have adopted the use of rapid-setting concrete (RSC) for the construction of connections between precast elements in ABC bridges, which are often treated as a “weak-links” in the ABC approach due to potential risk for inferior performance and durability concerns. This research aimed to access and explore correlations …

Mass Loading Model Of Per- And Polyfluoroalkyl Substances To New Hampshire's Great Bay With A Focus On Surface Waters, Gage Moran

Master's Theses and Capstones

Per- and polyfluoroalkyl substances (PFAS) have been used in manufacturing as textile stains, soil repellants, grease proof products, food product coatings, aqueous film forming foams, and more for over 50 years. The carbon-fluorine chain of these compounds is chemically and thermally stable, resistant to biodegradation, and has both hydrophobic and lipophobic properties, making its chemistry unique for many commercial and industrial uses. This research work gathered existing concentration information from New Hampshire’s Environmental Monitoring Database on PFAS in the watershed and discharging to the Great Bay to better frame monitoring locations, temporal trends, and data gaps in the watershed. A …

Movement Patterns, Habitat Use, And Survival Of Anadromous Rainbow Smelt In Great Bay Estuary, Nh, Chloe Pearson

Master's Theses and Capstones

Anadromous rainbow smelt in the northeastern USA have experienced range contraction over the past few decades, and are now restricted to waters in Massachusetts and northwards. In their current range, populations appear to be in decline, including in New Hampshire; in Great Bay, New Hampshire, conservation methods such as habitat restoration and stocking efforts have been suggested to improve populations, with projects underway to implement these methods. To optimize these conservation efforts, specific knowledge regarding rainbow smelt habitat use in estuaries is needed, including the specific habitats used as well as timing and duration of use. In March 2021, we …

Spatially Revealing The Liver’S Genetics In The Dehydration Resistant Cactus Mouse, Sean Pierre-Louis

Master's Theses and Capstones

This study is motivated by the global issue of climate change and its impact on the increasing prevalence of hot and arid environments, which in turn leads to water scarcity. While acknowledging these challenges, our research focuses on understanding the how desert-dwelling cactus mouse, P. eremicus, have adapt to their native desert environment. Using spatial transcriptomic sequencing, we created a spatial atlas of gene expression in hepatocytes and examined the baseline expression patterns in different zones. In this spatial atlas, hepatocyte genes were sequenced from their original spatial location in the tissue to establish the zonal patterns with neighboring hepatocytes. …

Unh Researchers Awarded Close To $3 Million To Develop Sustainable In-Space Manufacturing, Robbin Ray

Media Relations

No abstract provided.

Researchers Awarded Close To $3 Million To Develop Sustainable In-Space Manufacturing, Robbin Ray

UNH Today Archive

No abstract provided.

Office Of Research, Economic Engagement And Outreach Update, August 30, 2023, Office Of Research, Economic Engagement And Outreach

Office of Research, Economic Engagement and Outreach

No abstract provided.

Unh Rifc 50 Index Gains 6.7% In Q2 With Strong Recovery Of Franchising Sector, Robbin Ray

Media Relations

No abstract provided.

When The Gig Is Up; Gig Workers Don’T Always Trust Their Boss And That Might Be A Good Thing, Robbin Ray

Media Relations

No abstract provided.

Researchers Identify Unusually Large Bloom Of Brown Algae In Gulf Of Maine, Robbin Ray

Media Relations

No abstract provided.

Unh Students, Graduates Powering The Granite State With Eversource, Keith Testa

UNH Today Archive

No abstract provided.