Cross-shore and longshore sediment size distribution on southern Currituck Spit, North Carolina

Using Q-mode factor analysis, 87 surficial sediment samples collected from Duck and Whalehead beach, North Carolina, were analyzed using the weight percent of the gravel and sand fraction subdivided at 0.5 phi class interval as variables. An additional data set composed of 178 surficial sediment samples from Duck beach (bimodal) and Coquina beach (unimodal fine) representing three years of sampling at monthly intervals were analyzed by the same technique using only the sand fraction. The spatial and temporal patterns of sediment factor groups support three main inferences. (1) Bimodal beaches display a more distinct sediment zonation than unimodal beaches. (2) On a long term basis (yearly), cross-shore grain-size distributions represent depositional processes. Particularly on bimodal beaches, the association of sediment factor groups with specific zones of the beach profile delineates a textural differentiation produced by the type and amount of energy inherent in each zone. Combinations of Q-mode factor analysis and other environmental sensitive techniques (e.g. log-probability plots of grain-size distributions) proved to be useful for interpreting sedimentary processes at the depositional site. (3) The cross-shore patterns which represent an average of the sedimentary processes occurring under fair weather and storm conditions indicate that coarse sediments are concentrated on the backshore. In contrast, fine sediments are located landward or shoreward of this zone where they are exposed to energy conditions that result in their depletion in the subaerial beach. Using the Q-mode factor model, 350 new sediment samples from beaches located between Duck and Oregon Inlet were mapped in the factor space defined by the Duck-Coquina data set. The along-coast results support the cross-shore trends observed in the previous studies and indicates that there are several sources of coarse sediments between Duck and Oregon Inlet. Sedimentologic, stratigraphic and seismic data offshore and landward of the barrier substantiate these findings and demonstrate that differences in subaerial beach morphology in this part of Currituck Spit, is primarily due to the availability of coarse sediments from the paleodrainage of the Albemarle river

The ‘national turn’ in climate change loss and damage governance research: constructing the L&D policy landscape in Tuvalu

Loss and damage (L&D) is now a key area of climate policy. Yet studies of L&D governance have focused disproportionately on the international level while the national scale of analysis has been overlooked. Recent developments in the UNFCCC negotiations and a growing call for a ‘science of loss’ that can support policy-makers to address L&D suggest the need for a greater understanding of L&D governance at the national level. How do national policy-makers understand the concept of L&D? What types of policies have been developed, implemented and funded to address L&D? We study the paradigmatic case of Tuvalu to illustrate the value of turning to the national level of analysis, while recognizing that other countries might frame L&D and its relevance for the national context differently, and thus devise a diverse set of policy responses. Drawing on semi-structured interviews with national stakeholders and a systematic policy review using methods of interpretive policy analysis, we show that the concept of L&D was introduced in official documentation in 2012 and is not explicitly distinguished from adaptation. We find that managing L&D constitutes a complex governance system with competencies and responsibilities diffused across different national actors and multiple governance scales. As conceptualized by policy-makers and within policy documents, L&D is closely tied to issues related to national sovereignty, human mobility, infrastructure investment and protection of the Exclusive Economic Zone. We conclude by suggesting that there is a need for a ‘national turn’ in research on L&D governance to produce knowledge that will support policy-makers, but also argue that national level analyses will always need to be situated within a multi-scalar context

Microstructural and Corrosion Properties of Cold Rolled Laser Welded UNS S32750 Duplex Stainless Steel

The main goal of this work was to study the effect of plastic deformation on weldability of duplex stainless steel (DSS). It is well known that plastic deformation prior to thermal cycles can enhance secondary phase precipitation in DSS which can lead to significant change of the ferrite-austenite phase ratio. From this point of view one of the most important phase transformation in DSS is the eutectoid decomposition of ferrite. Duplex stainless steels (DSSs) are a category of stainless steels which are employed in all kinds of applications where high strength and excellent corrosion resistance are both required. This favorable combination of properties is provided by their biphasic microstructure, consisting of ferrite and austenite in approximately equal volume fractions. Nevertheless, these materials may suffer from several microstructural transformations if they undergo heat treatments, welding processes or thermal cycles. These transformations modify the balanced phase ratio, compromising the corrosion and mechanical properties of the material. In this paper, the microstructural stability as a consequence of heat history due to welding processes has been investigated for a super duplex stainless steel (SDSS) UNS S32750. During this work, the effects of laser beam welding on cold rolled UNS S32750 SDSS have been investigated. Samples have been cold rolled at different thickness reduction (\u3b5 = 9.6%, 21.1%, 29.6%, 39.4%, 49.5%, and 60.3%) and then welded using Nd:YAG laser. Optical and electronical microscopy, eddy\u2019s current tests, microhardness tests, and critical pitting temperature tests have been performed on the welded samples to analyze the microstructure, ferrite content, hardness, and corrosion resistance. Results show that laser welded joints had a strongly unbalanced microstructure, mostly consisting of ferritic phase (~60%). Ferrite content decreases with increasing distance from the middle of the joint. The heat-affected zone (HAZ) was almost undetectable and no defects or secondary phases have been observed. Both hardness and corrosion susceptibility of the joints increase. Plastic deformation had no effects on microstructure, hardness or corrosion resistance of the joints, but resulted in higher hardness of the base material. Cold rolling process instead, influences the corrosion resistance of the base material

Investigation of Electroplastic Effect on Four Grades of Duplex Stainless Steels

Since the late 1950s, an effect of electrical current in addition to joule heating on the deformation of metals called the Electroplastic Effect (EPE) has been known. It is used nowadays in the so-called Electrically Assisted Forming (EAF) processes, but the understanding of the phenomenon is not very clear yet. It has been found that EPE increases the formability of high stacking fault energy (SFE) materials, while low SFE materials reach fracture prematurely. Since Duplex Stainless Steels (DSSs) possess a microstructure consisting of two phases with very different SFE (low SFE austenite and high SFE ferrite) and they are widely used in industry, we investigated EPE on those alloys. Tensile tests at 5 A/mm2, 10 A/mm2 and 15 A/mm2 current densities along with thermal counterparts were conducted on UNS S32101, UNS S32205, UNS S32304 and UNS S32750. The DSS grades were characterized by means of optical microscopy, X-ray diffraction and their mechanical properties (ultimate tensile strength, total elongation, uniform elongation and yield stress). An increase in uniform elongation for the electrical tests compared to the thermal counterparts as well as an increase in total elongation was found. No differences were observed on the yield stress and on the ultimate tensile strength. Un uneven distribution of the current because of the different resistivity and work hardening of the two phases has been hypothesized as the explanation for the positive effect of EPE

Governing people on the move in a warming world: Framing climate change migration and the UNFCCC Task Force on Displacement

Different ways of framing the nexus between climate change and migration have been advanced in academic, advocacy and policy circles. Some understand it as a state-security issue, some take a protection (or human security) approach and yet others portray migration as an adaptation or climate risk management strategy. Yet we have little insight into how these different understandings of the ‘problem’ of climate change-related migration are beginning to shape the emergence of global governance in the climate regime. Through a focus on the UNFCCC Task Force on Displacement we argue that these different framings of climate change migration shape how actors understand the appropriate role of the TFD, including the substantive scope of its mandate; its operational priorities; the nature of its outputs and where it should be situated in the institutional architecture. We show that understanding the different framings of the nexus between climate change and migration – and how these framings are contested within the UNFCCC – can help to account for institutional development in this area of climate governance

High-energy events and short-term changes in superficial beach sediments

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Making sense of the politics in the climate change loss & damage debate

The Warsaw International Mechanism for Loss and Damage (L&D) associated with Climate Change Impacts (WIM) was established in 2013 to advance i) knowledge generation; ii) coordination and iii) support to address losses and damages under the UNFCCC. So far, the work undertaken by the WIM Executive Committee (ExCom) has focused on enhancing understanding and awareness of the issue and promoting collaboration with relevant stakeholders. Delivering on the WIM’s third function on action and support has lagged behind, and ‘the political’ nature of L&D has often been blamed for this. Key terrains of contention among Parties have included the positioning of L&D governance vis-à-vis the adaptation space and struggles around state liability and compensation. As a way to facilitate discussion on implementation options, recent research has suggested de-politicising aspects of the L&D debate; yet we have very little insight into how the politics are understood within the realm of international L&D governance. This paper brings an analysis of ‘the political’ into the picture by identifying the complex and underlying issues that fuel contention within UNFCCC L&D negotiations. It gives centre stage to the way different framings of norms and material interests affect the debate, and challenges the tendency in current L&D literature to overlook the socio-historical and political underpinnings of this area of policy-making. We employ a qualitative multi-methods research design which draws on content analysis of 138 official Parties’ submissions and statements, 14 elite interviews with key current and former L&D negotiators and is built on a foundation of 3 years of participant observation at COPs and WIM meetings. We approach this data with a political ethnographic sensibility that seeks to explore how meanings are constructed within and across different sources of data. Our empirical results show that, rather than being a monolithic dispute, L&D catalyses different yet intertwined unresolved discussions. We identify five areas of contention, including continued disputes around compensation; conflicts on the legitimacy of L&D as a third pillar of climate action; tensions between the technical and political dimension of the debate; debates over accountability for losses and damages incurred; and the connection of L&D with other unresolved issues under the Convention

Understanding the Politics and Governance of Climate Change Loss and Damage

This introduction to the 2023 special issue of Global Environment Politics brings questions related to politics and political processes to the forefront in the study of climate change loss and damage. The aim of avoiding the detrimental impacts of climate change has been at the heart of the international response to global climate change for more than thirty years. Yet the development of global governance responses to climate change loss and damage—those impacts that we cannot, do not or choose not to prevent or adapt to—has only over the last decade become a central theme within the discussions under the United Nations Framework Convention on Climate Change (UNFCCC). Loss and damage has also become a research topic of growing importance within an array of disciplines, from international law to the interdisciplinary environmental social sciences. However, the engagement of scholars working in the fields of political science and international relations has been more limited so far. This is surprising because questions about how to best respond to loss and damage are fundamentally political, as they derive from deliberative processes, invoke value judgments, imply contestation, demand the development of policies, and result in distributional outcomes. In this introduction we describe the context and contributions of the research articles in the special issue. By drawing on a wide range of perspectives from across the social sciences, the articles render visible the multifaceted politics of climate change loss and damage and help to account for the trajectory of governance processes