International Trade
M. Muendler, Kristy Buzard, Aaron Schroeder
et al.
A BROADSHEET, "Facts about International Trade" (No. 219), issued by P E P (Political and Economic Planning), describes developments since the P E P report on international trade was published in 1937, and is intended to form the starting point for a later examination of some of the main problems of postwar international trade. The main conclusions emerging from the report itself and the present broadsheet are, first, that exports are essentially a means of obtaining necessary or desirable imports: neither Britain, the United States nor any other country should export primarily to create home employment; export and import policy should be deliberately related to a nation's balance of payments and to its long-term foreign lending and borrowing. Secondly, trade restrictions and bilateralism were a symptom more than a cause of the decline in world trade after 1929; post-war policy should aim at a continuing expansion of effective world demand, making full use of the world's man-power and resources. Multilateral trade, while creating the necessary conditions for obtaining the greatest possible advantages from international trade, also heightens the economic interdependence of nations. A restoration of multilateral trade requires: (a) an efficient international monetary exchange clearing system in which all nations have complete confidence; (b) the maintenance of full employment within national economies; (c) the maximum attainable measure of political security. These three requirements are essential to a universal 'economy of peace'. Failing the establishment of a universal multilateral system of trade, the 'low-tariff club' represents a means by which nations most dependent on international trade can secure the benefits of multilateralism on a limited scale. 'Lend-lease' is essentially a war-time method of international exchange and is unlikely to continue after the immediate post-war period of securities; but world prosperity, like peace, is indivisible. Finally, Great Britain's major problem in foreign trade after the War is to increase her visible exports very considerably, to repair the inroads of war here and in overseas investment income, and to maintain the volume of imports vital to her standard of living.
Mechanical quality of hemp fiber as influenced by tillage, cover crop, and nitrogen management in regenerative organic systems
Dinesh Panday, Parinaz Heydar, Casey Lapham
et al.
Industrial hemp (Cannabis sativa L.) is an emerging crop for renewable fiber materials. For farmers, finding a balance between agronomic performance and economic return is crucial, especially when targeting specific markets like the textile industry, which values not just fiber quantity, but overall quality. This field study, conducted at the Rodale Institute in Kutztown, Pennsylvania, assessed the effects of tillage (till vs. no till), cover crop (with cover vs. no cover), and nitrogen (N) rate (0, 50, 100, 150 kg ha⁻¹) on hemp fiber yield, N concentrations in leaf and stalk, and mechanical performance under regenerative organic conditions. Fiber mechanical properties, including maximum load, tenacity, work of rupture, and modulus of elasticity were analyzed at Thomas Jefferson University. Results showed that biomass yield increased with N input, peaking at 9.2 Mg ha⁻¹ under till systems with cover crop at 150 kg N ha⁻¹ . However, fiber quality declined at higher N rates. The highest fiber quality metrics, including tenacity (610.5 MPa), modulus of elasticity (3.5 GPa), and work of rupture (31.4 newton mm⁻²) was achieved in no till system with cover crops and no N addition. A clear trade-off emerged: high N increased biomass yield but compromised fiber quality, while moderate input levels (e.g., till system with cover crop at 50 kg N ha⁻¹) offered a balanced outcome. This suggests that regenerative practices not only support soil health but also improve fiber strength and flexibility. Farmers can tailor input strategies to match end-use goals: low-input systems for premium textile fibers and moderate inputs for bio-composite applications, supporting both ecologically sound and market demands.
China and G7 in the Current Context of the World Trading
N. S. Gonchar, O. P. Dovzhyk, A. S. Zhokhin
et al.
The paper analyses trade between the most developed economies of the world. The analysis is based on the previously proposed model of international trade. This model of international trade is based on the theory of general economic equilibrium. The demand for goods in this model is built on the import of goods by each of the countries participating in the trade. The structure of supply of goods in this model is determined by the structure of exports of each country. It is proved that in such a model, given a certain structure of supply and demand, there exists a so-called ideal equilibrium state in which the trade balance of each country is zero. Under certain conditions on the structure of supply and demand, there is an equilibrium state in which each country have a strictly positive trade balance. Among the equilibrium states under a certain structure of supply and demand, there are some that differ from the ones described above. Such states are characterized by the fact that there is an inequitable distribution of income between the participants in the trade. Such states are called degenerate. In this paper, based on the previously proposed model of international trade, an analysis of the dynamics of international trade of 8 of the world's most developed economies is made. It is shown that trade between these countries was not in a state of economic equilibrium. The found relative equilibrium price vector turned out to be very degenerate, which indicates the unequal exchange of goods on the market of the 8 studied countries. An analysis of the dynamics of supply to the market of the world's most developed economies showed an increase in China's share. The same applies to the share of demand.
‘I’m not burning out, I’m rusting out’: investigating the causes of rustout in teacher educators in Ireland and the United Kingdom
Sabrina Fitzsimons, David S. Smith
Abstract Higher Education-Based Teacher Educators (TEs) are responsible for the preparation of future teachers across the continuum of education. However, despite their significant role in the education ecosystem, their well-being and professional satisfaction often remain overlooked in research and policy. For example, while burnout among academics is extensively studied, it remains under-researched, particularly among TEs. Even less attention is paid to rustout, a phenomenon characterised by professional underutilisation, intellectual stagnation and unfulfillment. Rustout is not a universal experience. However, its presence acknowledges that occupational stress is non-linear and nuanced and that it can vary depending on organisational and personal resources. Like its better-known counterpart, burnout, untreated rustout can have individual and organisational consequences, such as poor mental health, career dissatisfaction and accelerated employee turnover. Through an analysis of surveys and interviews with TEs across Ireland and the United Kingdom (UK), we explore the factors that may contribute to rustout. Guided by rustout literature and validated through collaborative reflection, this paper reveals three core themes: (1) administrative overload and erosion of autonomy, (2) misalignment between professional aspirations and job tasks and (3) systemic barriers to professional growth. Some participants reported being ‘prevented from thriving’, while others actively sought ways to mitigate rustout through new challenges or external opportunities. More broadly, the study shines a light on the ‘silence’ surrounding rustout in academia. The findings also highlight the detrimental effects of rustout on individual well-being and suggest that it is not merely a pre-retirement phenomenon but can emerge at various stages of a TE’s career. Practical implications emphasise the need for Higher Education (HE) sectors and leaders to put ‘rustout’ on the mental health literacy agenda, to balance job demands with resources and to acknowledge the trade-off that can occur when operational efficiency is prioritised over professional well-being.
History of scholarship and learning. The humanities, Social Sciences
Scenario-Based Assessment of Urbanization-Induced Land-Use Changes and Regional Habitat Quality Dynamics in Chengdu (1990–2030): Insights from FLUS-InVEST Modeling
Zhenyu Li, Yuanting Luo, Yuqi Yang
et al.
Against the backdrop of rapid urbanization in western China, which has triggered remarkable land-use changes and habitat degradation, Chengdu, as a developed city in China, plays a demonstrative and leading role in the economic and social development of China during the transition period. Therefore, integrated modeling approaches are required to balance development and conservation. This study responds to this need by conducting a scenario-based assessment of urbanization-induced land-use changes and regional habitat quality dynamics in Chengdu (1990–2030), using the FLUS-InVEST model. By integrating remote sensing-derived land-use data from 1990, 1995, 2000, 2005, 2010, 2015, and 2020, we simulate future regional habitat quality under three policy scenarios: natural development, ecological priority, and cropland protection. Key findings include the following: (1) From 1990 to 2020, cropland decreased by 1917.78 km<sup>2</sup>, while forestland and built-up areas increased by 509.91 km<sup>2</sup> and 1436.52 km<sup>2</sup>, respectively. Under the 2030 natural development scenario, built-up expansion and cropland reduction are projected. Ecological priority policies would enhance forestland (+4.2%) but slightly reduce cropland. (2) Regional habitat quality declined overall (1990–2020), with the sharpest drop (ΔHQ = −0.063) occurring between 2000 and 2010 due to accelerated urbanization. (3) Scenario analysis reveals that the ecological priority strategy yields the highest regional habitat quality (HQ<sub>mean</sub> = 0.499), while natural development results in the lowest (HQ<sub>mean</sub> = 0.444). This study demonstrates how the FLUS-InVEST model can quantify the trade-offs between urbanization and regional habitat quality, offering a scientific framework for balancing development and ecological conservation in rapidly urbanizing regions. The findings highlight the effectiveness of ecological priority policies in mitigating habitat degradation, with implications for similar cities seeking sustainable land-use strategies that integrate farmland protection and forest restoration.
Commercial Data Governance: Developing Typology-Based Intellectual Property Protections
Shiya Ma
With the rapid advancement of digital technologies, commercial data have emerged as fundamental elements of the digital economy, demonstrating increasing significance. Characterized by their intangible nature, non-rivalry, and non-excludability, commercial data exhibit substantial compatibility with intellectual property subject matter. The inherent flexibility of intellectual property regimes, coupled with the convergent legislative values of data protection and intellectual property governance, establishes both the feasibility and legitimacy of protecting commercial data within intellectual property frameworks. This context renders the introduction of a categorized protection approach that is theoretically valuable and practically significant. Within the framework of the intellectual property rights system, a classified protection system can be established based on the different characteristics of commercial data. For data collections that are original selections, the protection rules for compilations in copyright law can be applied. For commercial data that meet the requirements of secrecy, value, and confidentiality, protection can be provided through the trade secret system. For general commercial data that have been deeply processed but lack originality or secrecy, exploring the establishment of a new type of data intellectual property rights system is necessary in order to achieve a balance of interests by granting limited exclusive rights. Such differentiated protection mechanisms would systematically address the heterogeneous nature of commercial data assets while maintaining appropriate incentives for data production and circulation in digital markets.
Mechanistic evolution of lamellar heterostructures in high-manganese TWIP steel: Annealing-driven recrystallization and bimodal grain formation
Yaozhou Xie, Zhi Wang, Hangyu Dong
et al.
This study systematically investigates the annealing temperature-dependent microstructural evolution and strengthening mechanisms in a cold-rolled (50 % reduction) high-manganese TWIP steel (0.4C-23.8Mn-0.2Si-3.7Cr-0.5Cu). EBSD and TEM analyses reveal that annealing at 600 °C triggers preferential recrystallization nucleation along deformation twin interfaces, generating a bimodal lamellar heterostructure (1.32 ± 1.98 μm) characterized by fine recrystallized grains and recovered coarse grains. This bimodal distribution arises from divergent growth kinetics, where recrystallized grains nucleate while recovered grains coarsen, evidenced by a sharp decline in Σ3 boundary fraction (51.5 % → 38.6 %) with minimal change in grain orientation spread (7.08° → 5.98°). The heterostructure enables synergistic strengthening via hetero-deformation-induced (HDI) hardening at hetero-zone boundaries, which alleviates stress concentration and delays strain localization. Consequently, the 600 °C annealed sample achieves an optimal strength-ductility balance (yield strength: 1051 MPa, total elongation: 22 %), superior to samples annealed at other temperatures (400–800 °C). Nanoindentation analysis further quantifies substructure contributions, confirming dislocation-dominated hardening in nucleation-stage microstructures and validating the inadequacy of conventional Hall-Petch models for heterogeneous systems. The work establishes annealing at 600°C-700 °C as critical for activating bimodal lamellar heterostructures, providing a mechanistic framework to overcome strength-ductility trade-offs in TWIP steels.
Mining engineering. Metallurgy
Optimization of ISAC Trade-Off via Covariance Matrix Allocation in Multi-User Systems
Danaisy Prado-Alvarez, Daniel Calabuig, Saúl Inca
et al.
Integrated Sensing and Communication (ISAC) is envisioned as a foundational technology for future wireless networks, enabling simultaneous wireless communication and environmental sensing using shared resources. A key challenge in ISAC systems lies in managing the trade-off between communication data rate and sensing accuracy, especially in multi-user scenarios. In this work, we investigate the joint design of transmit signal covariance matrices to optimize the sum data rate while ensuring certain sensing performance. Specifically, we formulate a constrained optimization problem where the transmit covariance matrix is allocated to maximize the communication sum-rate under sensing-related constraints. These constraints condition the design of the transmit signal’s covariance matrix, impacting both the sensing channel estimation error and the sum data rate. Our proposed method leverages convex optimization tools to achieve a principled balance between communication and sensing. Numerical results demonstrate that the proposed approach effectively manages the ISAC trade-off, achieving near-optimal communication performance while satisfying sensing requirements.
Urban Greenprint: A Decision Support Tool for Optimizing Urban Forest Strategies in Sustainable Cities
Marco di Cristofaro, Federico Valerio Moresi, Mauro Maesano
et al.
Urban forests (UFs) play a crucial role in mitigating climate change, but their management presents complex trade-offs between environmental, economic, and social aspects. We developed a Decision Support Tool (DST) to simulate 27-year UF dynamics under six different management strategies, aiming to maximize socio-economic and environmental benefits while considering costs. Business as Usual (BaU), Yielding Scenario (YS), High Management (HM), Forest Development (FD), Social Boost (SB), and Cover Maximizing (CM) strategies were tested with the DST in the Vazzieri district of Campobasso, central Italy. The DST integrates CO<sub>2</sub> removal, management expenditures and revenues, and the social usability of UFs. The findings show that while all the strategies contribute to climate change mitigation, FD and SB offer the best balance between the environmental and social sides. FD demonstrates significant CO<sub>2</sub> removal with moderate expenditures, whereas SB maximizes CO<sub>2</sub> removal despite its high management expenditures. Otherwise, YS and BaU show limited environmental benefits with beneficial economic outcomes. While achieving the highest environmental and social benefits, CM incurs the greatest economic costs. This study highlights the need for long-term, integrated UF strategies to harmonize climate change mitigation with economic viability and social inclusivity. The DST provides a valuable framework for urban planners and policymakers to optimize sustainable UF management.
Geography. Anthropology. Recreation, Social Sciences
Oil Price Shock and Trade Balance in Nigeria
J. Ozigbu
This study used the Brent crude oil price to examine whether the variability in the trade balance of Nigeria is linked to the fluctuation in oil price.To achieve this, the study used annual frequency data from 1981 to 2021 sourced from the United Nations Conference on Trade and Development (UNCTAD), the World Bank’s World Development Indicator (WDI), and the Central Bank of Nigeria (CBN) Statistical Bulletin. The bound test procedure to cointegration was adopted and the nexus between oil shock and trade balance was examined within the autoregressive distributed lag (ARDL) framework. Additionally, the augmented Dickey-Fuller approach to unit root was used in determining the degree of integration of the series. Certain findings were made from the analyses. First, the study confirmed that there is long-run relationship among the variables. Second, oil price hikes lead to a surplus trade balance in the long run, but only insignificantly. Contrariwise, the positive impact of oil price hikes on the trade balance in the short run was significant. Third, the study found that inflation had an insignificant positive effect on the trade balance. Fourth, the estimation revealed that an increase in real effective exchange rate and trade openness is insignificant and lead to a deficit trade balance in the long run. The study recommends that domestic oil shocks in the form of low oil production should be mitigated by addressing the security challenges in the country.
Trade Wars with Trade Deficits
Pau Pujolas, Jack Rossbach
Trade imbalances significantly alter the welfare implications of tariffs. Using an illustrative model, we show that trade deficits enhance a country's ability to alter its terms of trade, and thereby benefit from tariffs. Greater trade deficits imply higher optimal, or welfare maximizing, tariffs. We compute optimal unilateral and Nash equilibrium tariffs between the United States and China $\unicode{x2014}$ the countries with the largest bilateral trade imbalance $\unicode{x2014}$ using a multi-region, multi-sector applied general equilibrium model with service sectors and input-output linkages, a computationally complex task. Free trade benefits both countries compared to a trade war. Relative to existing tariff rates, however, the United States gains from a trade war with China $\unicode{x2014}$ a result that hinges on their bilateral trade imbalance.
Ecosystem Service Trade-Offs in Peri-Urban Landscapes: Drivers, Governance Obstacles and Improvements
Marcin Spyra, Nica Claudia Caló, Guillermo J. Martínez Pastur
et al.
Trade-offs in ecosystem services (ESs) manifest when the enhancement of one service leads to the diminishment of another. These trade-offs pose a notable challenge, impacting the sustainability of particular socioecological system peri-urban landscapes (PULs). This issue arises from the dynamic processes associated with peri-urbanization, which threaten natural ecosystems and their services in peri-urban areas. Additionally, the escalating demand for ecosystem services in PULs contributes to these trade-offs. Policymaking and planning concerning ES trade-offs in PULs should prioritize promoting a balance between conflicting services and fostering synergies among them. However, it is noteworthy that ES trade-offs in PULs are not given high priority in policy and planning agendas. Knowledge regarding policy development and planning for ES trade-offs in PULs often remains concealed within specific country and regional case studies. Consequently, this research seeks to characterize the ES trade-offs in selected PUL case studies, with the objective of identifying potential commonalities among them. Furthermore, this study aims to identify (i) the factors driving ES trade-offs, (ii) challenges related to how policymaking and planning address ES trade-offs in PULs, and (iii) recommendations for enhancing governance practices to better manage peri-urban ES trade-offs. We designed a semi-quantitative survey and collected information about 24 case studies located across the world. The answers from this survey were analyzed using principal component analysis. The results showed that the most common trade-offs occurred between “cultural and provisioning” and “regulating and provisioning” ESs. It was found that urban development is the primary driver behind the emergence of the examined trade-offs. To address this issue at the governance level, this study recommends establishing mechanisms to facilitate collaboration among stakeholders. This should be accompanied by robust dissemination efforts and the promotion of awareness among actors regarding the fundamental concepts of ESs and PULs.
North Korea’s COVID-19 policy dilemma: epidemic prevention conflicting with trade
Byungjin Park, Joonmo Cho
Abstract Background Amidst the COVID-19 pandemic, striking a delicate balance between sustaining economic activity and safeguarding public health has become a crucial concern. The border closures for COVID-19 prevention have further intensified concerns for North Korea, which conducts over 90% of its trade with China and Russia, countries sharing its borders. Methods This study aims to scrutinize North Korea’s response to these competing imperatives by examining the impact of border closures on the country’s trade dynamics with China and Russia. This study employed the difference-in-difference (DID) method to analyze transformations in North Korea’s economic activity before and after the border closures, utilizing trade data and nighttime satellite imagery captured in 2019 and 2020. Results The results reveal that North Korea actively reoriented its trade priorities towards Russia and accorded precedence to its epidemic prevention system over its economy during the pandemic. A noticeable increase in imports of food and pharmaceuticals was observed, indicating a significant rise in the inflow of these essential commodities. Conclusion The findings of this study suggest that during the early stages of the COVID-19 pandemic, North Korea placed significant policy emphasis on preserving public health. However, due to economic hardships and food shortages, if the pandemic persists in the long term, it indicates the possibility of partial or complete lifting of border closures to mitigate these challenges.
Public aspects of medicine
Interpreting EU Internal Market Powers in Light of Article 9 TFEU Social Objectives: Implications for the Attribution of Competences
Silvia Giudici
The inclusion of the so-called ‘horizontal social clause’, namely Article 9 TFEU, in EU primary law imposes on the EU legislator an obligation to balance the objectives of a specific policy area with the social interests contained therein. For instance, when adopting internal market measures pursuant to Article 114 TFEU, the EU legislator would need to reconcile free trade aims and social interests. At the same time, this process also has consequences on the scope of EU competences. Hence, this article analyses which implications related to the scope of EU competences stem from the obligation to read Article 114 TFEU in light of Article 9 TFEU. In addition, it accounts for the consequences that this process entails for the division of powers between the EU and the Member States. The main argument proposed is that the obligation to read internal market powers in light of Article 9 TFEU not only influences the use of EU competences to pursue certain social objectives, but also leads to an expansion of EU harmonising powers in domains that remain of national competence. Thus, the division between EU and Member State competences becomes increasingly blurred. The Court of Justice of the EU has favoured this tendency by recognising on many occasions the possibility for the EU to rely on Article 114 TFEU, while developing a restrictive interpretation of the limitations of EU competences in social fields enshrined in the Treaties.
Oligopoly and exchange rate dynamics in Nigeria
Omolara Omotunde Duke, Adeniyi Olatunde Adenuga, Toyin Segun Olusegun
et al.
We examine the short-run and long-run oligopoly - exchange rate nexus, with a focus on access to forex in Nigeria, using the Autoregressive Distributed Lag (ARDL) model; controlling for other macroeconomic fundamentals (inflation rate, interest rate, oil price, and net trade balance). Oligopoly is defined using the Herfindahl-Hirshman Index (HHI) on the sectoral utilization of foreign exchange in Nigeria. While the concentration in forex allocation to firms and industries became oligopolistic between 2014 and 2015, the Naira/USD exchange rate also recorded a jump from N164.8/US$ to N195.5/US$; indicating possible association. Oligopoly in forex allocation in Nigeria caused a weakly (strongly) significant appreciation (depreciation) in the exchange rate in the short-run (long-run). Imperatively, the exchange rate benefits of forex allocation to selected big firms are not sustainable. Net trade balance and oil price also reduced the pressure on Nigeria's forex market and stimulated potential Naira appreciation, but only in the short run; suggesting the need to diversify the economy from reliance on oil-based trade and embrace a more sustainable trade path.
No-Regret Learning in Bilateral Trade via Global Budget Balance
Martino Bernasconi, Matteo Castiglioni, A. Celli
et al.
Bilateral trade models the problem of intermediating between two rational agents — a seller and a buyer — both characterized by a private valuation for an item they want to trade. We study the online learning version of the problem, in which at each time step a new seller and buyer arrive and the learner has to set prices for them without any knowledge about their (adversarially generated) valuations. In this setting, known impossibility results rule out the existence of no-regret algorithms when budget balanced has to be enforced at each time step. In this paper, we introduce the notion of global budget balance, which only requires the learner to fulfill budget balance over the entire time horizon. Under this natural relaxation, we provide the first no-regret algorithms for adversarial bilateral trade under various feedback models. First, we show that in the full-feedback model, the learner can guarantee Õ(√T) regret against the best fixed prices in hindsight, and that this bound is optimal up to poly-logarithmic terms. Second, we provide a learning algorithm guaranteeing a Õ(T 34) regret upper bound with one-bit feedback, which we complement with a Ω(T 57) lower bound that holds even in the two-bit feedback model. Finally, we introduce and analyze an alternative benchmark that is provably stronger than the best fixed prices in hindsight and is inspired by the literature on bandits with knapsacks.
21 sitasi
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Computer Science
Investigating the Dynamic Relationship between Exchange Rate and Trade Balance in Egypt: ARDL Bounds Testing Approach
M. Abonazel, Abanoub M. Shafik, Suzan Abdel-Rahman
Exchange rate policies are among the most important economic tools in the country for their impact on the balance of payments in general and the balance of trade. This study used the autoregressive distributed lag (ARDL) model to estimate the long-term relationship between the exchange rate and the trade balance deficit while clarifying the impact of potential determinants during the period 1990 to 2021 in Egypt. The data for trade balance and its economic determinants (exchange rate, foreign direct investment, and money supply) was obtained from the World Bank. The results indicated that the best model was ARDL (2,1,2,3). The exchange rate is found to have a significant negative effect on the trade balance, confirming the perceptions of the economic theory. The money supply is positively and significantly related to the trade balance while there is no significant effect of foreign direct investment in the long term on the trade balance deficit. Economic adjustments between the four variables occur in the short run (after about 14 months only). The study recommends continuing the policy of liberalizing the exchange rate while working on expanding the production base to increase exports.
No-Regret Learning in Bilateral Trade via Global Budget Balance
Martino Bernasconi, Matteo Castiglioni, Andrea Celli
et al.
Bilateral trade models the problem of intermediating between two rational agents -- a seller and a buyer -- both characterized by a private valuation for an item they want to trade. We study the online learning version of the problem, in which at each time step a new seller and buyer arrive and the learner has to set prices for them without any knowledge about their (adversarially generated) valuations. In this setting, known impossibility results rule out the existence of no-regret algorithms when budget balanced has to be enforced at each time step. In this paper, we introduce the notion of \emph{global budget balance}, which only requires the learner to fulfill budget balance over the entire time horizon. Under this natural relaxation, we provide the first no-regret algorithms for adversarial bilateral trade under various feedback models. First, we show that in the full-feedback model, the learner can guarantee $\tilde O(\sqrt{T})$ regret against the best fixed prices in hindsight, and that this bound is optimal up to poly-logarithmic terms. Second, we provide a learning algorithm guaranteeing a $\tilde O(T^{3/4})$ regret upper bound with one-bit feedback, which we complement with a $Ω(T^{5/7})$ lower bound that holds even in the two-bit feedback model. Finally, we introduce and analyze an alternative benchmark that is provably stronger than the best fixed prices in hindsight and is inspired by the literature on bandits with knapsacks.
Decentralized Energy Market Integrating Carbon Allowance Trade and Uncertainty Balance in Energy Communities
Yuanxi Wu, Zhi Wu, Wei Gu
et al.
With the sustained attention on carbon neutrality, the personal carbon trading (PCT) scheme has been embraced as an auspicious paradigm for scaling down carbon emissions. To facilitate the simultaneous clearance of energy and carbon allowance inside the energy community while hedging against uncertainty, a joint trading framework is proposed in this article. The energy trading is implemented in a peer-to-peer (P2P) manner without the intervention of a central operator, and the uncertainty trading is materialized through procuring reserve of conventional generators and flexibility of users. Under the PCT scheme, carbon allowance is transacted via a sharing mechanism. Possible excessive carbon emissions due to uncertainty balance are tackled by obliging renewable agents to procure sufficient carbon allowances, following the consumption responsibility principle. A two-stage iterative method consisting of tightening McCormick envelope and alternating direction method of multipliers (ADMM) is devised to transform the model into a mixed-integer second-order cone program (MISOCP) and to allow for a fully decentralized market-clearing procedure. Numerical results have validated the effectiveness of the proposed market model.
Angular momentum balance in gravitational two-body scattering: Flux, memory, and supertranslation invariance
Massimiliano Maria Riva, Filippo Vernizzi, Leong Khim Wong
Two puzzles continue to plague our understanding of angular momentum balance in the context of gravitational two-body scattering. First, because the standard definition of the Bondi angular momentum $J$ is subject to a supertranslation ambiguity, it has been shown that when the corresponding flux $F_J$ is expanded in powers of Newton's constant $G$, it can start at either $O(G^2)$ or $O(G^3)$ depending on the choice of frame. This naturally raises the question as to whether the $O(G^2)$ part of the flux is physically meaningful. The second puzzle concerns a set of new methods for computing the flux that were recently developed using quantum field theory. Somewhat surprisingly, it was found that they generally do not agree with the standard formula for $F_J$, except in the binary's center-of-mass frame. In this paper, we show that the resolution to both of these puzzles lies in the careful interpretation of $J$: Generically, the Bondi angular momentum $J$ is \emph{not} equal to the mechanical angular momentum $\mathcal{J}$ of the binary, which is the actual quantity of interest. Rather, it is the sum of $\mathcal{J}$ and an extra piece involving the shear of the gravitational field. By separating these contributions, we obtain a new balance law, accurate to all orders in $G$, that equates the total loss in mechanical angular momentum $Δ_\mathcal{J}$ to the sum of a radiative term, which always starts at $O(G^3)$, and a static term, which always starts at $O(G^2)$. We show that each of these terms is invariant under supertranslations, and we find that $Δ_\mathcal{J}$ matches the result from quantum field theory at least up to $O(G^2)$ in all Bondi frames. The connection between our results and other proposals for supertranslation-invariant definitions of the angular momentum is also discussed.