Effective coastal adaptation to sea-level rise requires an understanding of how much and how fast glaciers and ice sheets will melt in the coming decades, together with an understanding of the provenance of that ice melt. When land ice is lost to the oceans, sea-levels do not rise uniformly across the globe, but exhibit a “sea-level fingerprint” specific to the source of ice melt, posing an important question motivating this thesis: Which ice mass(es) will contribute the first 1m/3 feet of sea-level rise? The glacial-geologic record archives the vulnerability of ice sheets and their sub-sectors to past warming. To analyze this record of past glacial change, I develop and apply cosmogenic-nuclide techniques for investigating the climate sensitivity of four key ice sheets. The novel geochemical techniques described here also allow me to investigate processes of landscape evolution, including subglacial and subaerial erosion. Subglacial erosion dictates landscape development in glaciated and formerly glaciated settings, which in turn influences ice-flow dynamics and the climate sensitivity of ice masses, making it an important input in ice-sheet models. In Chapter 1, I use 10Be measurements in surficial bedrock and a 4-m-long bedrock near Jakobshavn Isbræ, to constrain the erosion rate beneath the Greenland Ice Sheet (GrIS) on historical and orbital timescales. 10Be concentrations measured below ~2 m depth in a 4-m-long bedrock core are greater than what is predicted by an idealized production-rate depth profile and I develop a model to utilize this excess 10Be at depth to constrain orbital-scale erosion rates. I find that erosion rates beneath GrIS were 0.4–0.8 mm yr-1 during historical times and 0.1–0.3 mm yr-1 on Pleistocene timescales. The broad similarity between centennial- and orbital-scale erosion rates suggests that subglacial erosion rates adjacent to Jakobshavn Isbræ have remained relatively uniform throughout the Pleistocene. In Chapter 2, I present cosmogenic 10Be and 3He data from Ferrar dolerite pyroxenes in surficial rock samples and a bedrock core from the McMurdo Dry Valleys, Antarctica, opening new opportunities for exposure dating in mafic rocks. I describe scalable laboratory methods for isolating beryllium from pyroxene, estimate a spallation production rate for 10Be in this mineral phase, referenced to 3He, of 3.6 ± 0.2 atoms g-1 yr-1, and present initial estimates for parameters associated with 10Be and 3He production by negative muon capture. I also demonstrate that the 10Be-3He pair in pyroxene can be used to simultaneously resolve exposure ages and subaerial erosion rates, and that the precision of my 10Be measurements in pyroxene enable exposure dating on Last Glacial Maximum to Late Holocene surfaces, including moraines, on a global scale. In Chapter 3, I apply exposure dating locally to investigate the Last Glacial Maximum (LGM) and initial deglaciation of the Laurentide Ice Sheet (LIS), the most dynamic continental ice sheet, in southern New England and New York City. I synthesize new and existing exposure age chronologies from moraines and other glacial deposits that span ~26 to 20.5 ka, and quantify retreat rates for the southeastern LIS margin. Initial retreat at <5 to 30 m yr-1 started within the canonical LGM period, representing the slowest LIS retreat rates of the entire New England deglacial record, which I relate to a slow rise in modeled local summer temperatures through the LGM. Employing similar exposure dating techniques in Chapter 4, I describe the first 10Be ages from nunataks of the Juneau Icefield (JIF), Alaska, that I collected through the Juneau Icefield Research Program (JIRP) in order to evaluate icefield thinning during the Late Glacial and Holocene. I find that the JIF was smaller-than-present under warm climate conditions during the early-to-mid Holocene, elucidating the sensitivity of the icefield to warming. Tackling the climate crisis more broadly and in turn, addressing pressing Earth science questions like those posed in this dissertation, requires diverse perspectives. Yet, the Earth sciences have historically been among the least diverse of the STEM disciplines. As one contribution to a comprehensive effort through JIRP to increase diversity in the geosciences pipeline, Chapter 5 details the curriculum for a two-week course titled ‘A Virtual Expedition to the Juneau Icefield’ that I co-designed and co-taught in 2021 to bring accessible polar science experiences to high school students.

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Procrastination is a pervasive problem in education. In computer science, procrastination and lack of necessary time management skills to complete programming projects are viewed as primary causes of student attrition. The most effective techniques known to reduce procrastination are resource-intensive and do not scale well to large classrooms. In this thesis, we examine three course interventions designed to both reduce procrastination and be scalable for large classrooms. Reflective writing assignments require students to reflect on their time management choices and how these choices impact their classroom performance. Schedule sheets force students to plan out their work on an assignment. E-mail alerts inform students of their current progress as they work on their projects, and provide ideas on improving their work behavior if their progress is found to be unsatisfactory. We implemented these interventions in a junior-level course on data structures. The study was conducted over two semesters and 330 students agreed to participate in the study. Data collected from these students formed the basis of our analysis of the interventions. We found a statistically significant relationship between the time a project was completed and the quality of that work, with late work being of lower quality. We also found that the e-mail alert intervention had a statistically significant effect on reducing the number of late submissions. This result occurred despite students responded negatively to the treatment. / Master of Science

The objective of this research was to establish a relationship between arc spot weld shear strength and the arc time used to form the weld. Lap shear tests were performed on both 3/4 in. and 5/8 in. nominal diameter welds. Each weld was formed in one-, two-, or four-layers of sheet steel ranging from 22 gauge (0.028 in.) to 16 gauge (.057 in.). Three distinct time series were tested for each unique weld size, thickness of sheet steel and layer configuration. The first of these series were the full-time welds. The two remaining series, 2/3-time and 1/3-time welds, had arc times equal to 2/3 and 1/3 of the average full-time weld arc time, respectively. Both weld shear strength tests and weld sectioning were performed for each series of weld. Strength tests were performed on a minimum of three specimens from every weld series. If the strength of any specimen deviated by over ten percent from the mean strength, an additional specimen was tested, helping to better understand the true behavior of the weld. Comparisons were made between the strengths of full-time, 2/3-time and 1/3-time welds. Comparisons were also made between the observed strength of each weld and the strengths calculated using the 2001 AISI Specification. Each sectioning test involved measuring and documenting the visual diameter, average diameter and effective diameter of the weld. Weld penetrations were also documented as sufficient or insufficient and any porosity was noted. A single sectioning test was performed for each full-time series, while three were performed for every 2/3-time and 1/3-time series. The data taken from the strength tests and the sectioning samples proved that welds formed using reduced arc times were considerably smaller and weaker than full-time welds. The tests also proved that proper penetration is not dependent on the arc time, but is instead a function of the welding current and sheet steel thickness. / Master of Science

Systemic risk is a complex topic, with a large number of variables and constraints. In this thesis we introduce an agent-based network to study the effects of financial shocks on the financial network. The model takes into consideration the repurchase agreement (repo) market and rehypothecation. We introduce a financial network consisting of financial agents who are connected through direct channels (bilateral contracts) and indirect channels (markets). Each fi- nancial agent has a balance sheet with liquid assets (cash), collateral (bonds, shares), reverse repo assets, fixed assets (loans and mortgages) on the asset side and repo loans, deposits and equities on the liability side. Agents (i.e., banks) need to satisfy constraints on (i) liquidity, which deals with financial shocks, (ii) collateral, related to repo liabil- ities, rehypothecation, and (iii) solvency constraints, ensuring that equity is positive. Liquidity constrain can be broken by a financial shock (e.g., a bank run), while the collateral constraint can be broken by hoarding credit and collateral price reduction. When liquidity and collateral constraints are broken the financial agent will try to fix them through recalling reverse repos and firesale of fixed assets. Banks that fail to fix their constraints by the end of the day will be considered defaulted. We introduce netting and novation techniques to deal with defaulted banks and lower the stress on the financial markets. In the netting step we lower the exposure of financial agents by removing cycles in the repo liabilities between banks, while in the novation we redistribute the ownership of bilateral contracts and settle any residuals that are left. We also establish that, under certain conditions on the set of defaulted banks, that the novation step is order indifferent. Different network topologies and balance sheet compositions are tested under several financial shocks to check the robustness of the financial network under our framework. / Thesis / Doctor of Philosophy (PhD)

Among global steel markets in recent years, China steel industry expands the fastest with the largest capacity and most fiercest competitions, also bringing the greatest impacts to global and Taiwan steel markets. A few aggressive Taiwan mills have set up their production facilities in China and commissioned. This study conducts in-depth analysis on the leading Taiwan middlestream galvanizers & coil coaters (the products are hot-dip galvanized & pre-painted steel sheets, hereinafter called ¡§galvanized & pre-painted steel¡¨). Besides, the steel works are categorized into Taiwan works, China works-Taiwan capital, China works-foreign capital, and China local works based on different capital sources. Analysis and evaluation are done in light of every activity in value chain. Six types of galvanizers & coil coaters are categorized based on different facilities and processes. Type I: Integrated galvanizers & coil coaters Type II: CSP galvanizers & coil coaters Type III: Independent galvanizers Type IV: Independent coil coaters Type V: Independent galvanizers & coil coaters Type VI: Independent full-process galvanizers & coil coaters Owing to their different market environments, development backgrounds, technologies, human resources and management, this study will analyze their strengths, strategies adopted, possible future development trends and potential challenges. This study especially focuses on one issue: in the atmosphere of competition and cooperation between steel mills in Taiwan and China, how China independent galvanizers & coil coaters-Taiwan capital and Taiwan parent company upgrade their competitiveness is crucial. Synthesizing related literature & theories, market & mill information and interviews, verifying by comparison, four conclusions are obtained as follows. 1. The more value chain activities a mill has, the more profits and stronger competitiveness it acquires. 2. Taiwan markets of galvanizing & pre-painted steel are already saturated. The competitiveness & development strategy a globalization enterprise should adopt is to increase its export percentages and establish offshore production bases. 3. For those mills setting up independent galvanizers & coil coaters in both China and Taiwan, the marketing strategies they should employ are described as follows. 3.1 Both China and Taiwan works receive orders and manufacture for their domestic markets. In terms of exports, only Taiwan parent company receives orders for both. But they export through Taiwan¡¦s existing channels globally. 3.2 To ally with different downstream industries and benefit each other. 3.3 China products are exported to ASEAN 10 nations, or 10+3, or 10+4, or any country that hasn¡¦t accuse China mills of dumping, whereas Taiwan products are sold to China, or any country that hasn¡¦t accuse Taiwan mills of dumping. 3.4 Products should be differentiated. Order receiving, production planning, lead-time and customer service should be flexible and elastic. 3.5 The chosen customers and suppliers must be big and strong in their region. Thus, the overall enterprise competitiveness is excellent. 4. In the past, steel companies self-expand to grow whereas today they grow via merger and acquisition. Any enterprise must have its value-creation strategy, i.e. it must have a growth strategy to react to the fierce market competitions. This study provides six recommendations for the competitiveness & growth strategies which could be adopted by domestic Taiwan independent galvanizers & coil coaters. 1. For the investors who invest in independent galvanizers & coil coaters for the first time, the first choice should be Type VI: independent full-process galvanizers & coil coaters. The second choice should be Type V: Independent galvanizers & coil coaters. Next, to set up an independent galvanizer is superior to an independent coil coater. 2. Independent Galvanizers & Coil Coaters should adopt the growth strategy that horizontal developing to a certain scale at the outset is the priority. Next, they should develop toward upstream instead of downstream. In order to eliminate capacity, they should ally with different downstream industries. 3. In the market of demand exceeding supply, mills usually self-expand to achieve larger scale. Nevertheless, when the market is oversupplied, it is recommended to adopt acquisitions. 4. Independent galvanizers & coil coaters choose the most beneficial investment items & scale and start their oversea development based on their growth strategies. 5. In the initial phase of plant construction, independent galvanizers & coil coaters should negotiate with upstream raw material suppliers regarding raw material supply matters. A good relationship should be built in order to secure stability of raw material sources. 6. To manage China mills-Taiwan capital and compete with other mills, the following measures are recommended. 6.1 To take advantage of the enterprise strength, develop specialized products and promote marketing features. 6.2 To promptly establish market reaction mechanism via the internationalization strategy of ¡§Integration-Responsiveness¡¨. 6.3 To employ human resources management to aid internationalization strategy. 6.4 Integration model created by overseas plant construction or acquisition can be adopted to integrate an enterprise¡¦s organization, culture and resources via dynamics management system.

This diploma thesis covers a solution of designing the information system for HNS mechanix ltd. This company provides auditorial services of optical products. During the desining not only the requirements of functionality and attributes of the system itself but also implementation and developing tools are necessary to be followed. The system is required to be available as WWW service with multilevel user access.

In this thesis we investigate current sheets in the solar corona. The well known 1D model for the tearing mode instability is presented, before progressing to 2D where we introduce a non-uniform resistivity. The effect this has on growth rates is investigated and we find that the inclusion of the non-uniform term in η cause a decrease in the growth rate of the dominant mode. Analytical approximations and numerical simulations are then used to model current sheet formation by considering two distinct experiments. First, a magnetic field is sheared in two directions, perpendicular to each other. A twisted current layer is formed and we find that as we increase grid resolution, the maximum current increases, the width of the current layer decreases and the total current in the layer is approximately constant. This, together with the residual Lorentz force calculated, suggests that a current sheet is trying to form. The current layer then starts to fragment. By considering the parallel electric field and calculating the perpendicular vorticity, we find evidence of reconnection. The resulting temperatures easily reach the required coronal values. The second set of simulations carried out model an initially straight magnetic field which is stressed by elliptical boundary motions. A highly twisted current layer is formed and analysis of the energetics, current structures, magnetic field and the resulting temperatures is carried out. Results are similar in nature to that of the shearing experiment.