Historical Forces Research Articles

Interaction between ice cover and floating platform simulated by dilated-polyhedron-based DEM

This study presents a dilated-polyhedron-based discrete element method (DPDEM) aimed at investigating the interaction between the self-propelled ice-resistant platform (IRSPP) and drifting sea ice. The IRSPP is treated as a rigid body anchored by a mooring system, providing six degrees of freedom (6-DOF) in translations and rotations. The simulation of the ice-IRSPP interaction utilizes the DPDEM, incorporating contact forces and bond-failure criteria to account for sea ice collisions and fractures, respectively. To address disparities between DEM sea ice and actual sea ice, as well as the random nature of fracture and fragmentation following IRSPP interaction, an analysis of the dimensional independence of DEM calculation elements is conducted. Additionally, the validity of DEM parameters is assessed by comparing the numerical ice resistance of various previous icebreakers with the Lindqvist formula. Then, the time history of structural ice forces, ice heeling moments, and platform motion responses under varying ice floe thicknesses are investigated. Furthermore, the influences of sea ice conditions on ice load and the value of the ice heeling moment for the IRSPP are analyzed.

Free falling of nonspherical particles in Newtonian fluids, B: Acceleration

The acceleration length of nonspherical particles is required for various aspects of system design. However, no simple or usable equations can be found in literature. Therefore, this study is designed to show that the force balance developed earlier for spherical particles, including the new exponential function for the history force, is also valid for nonspherical particles. To achieve this, a new history force parameter definition considering sphericity has been developed based on numerous experiments. The experimental results confirm the definitions of particle acceleration and velocity of nonspherical particles. The acceleration length can be described as a function of the Archimedes number, density ratio, and particle diameter by analogy to spherical particles, considering the terminal Reynolds number, drag coefficient, and history force parameter as functions of the sphericity. In most cases, the acceleration length describes the experiments well, but it is less accurate for cases of orientation change during acceleration.

Towards a green and just industry? Insights from traditional leather districts in Southern Italy

Artisanal processes are crucial for examining major economic development, industrial, and historical forces. Among the different industries, fashion is regarded as one of the most polluting business activities. The indication of origin “Made in Italy” has found extensive scholarly economic appetite; however, the leather sector in its socioeconomic and environmental components has been scarcely investigated. The paper at hand analyzes selected leather poles in Campania, Italy – namely, the tanning, shoes, and gloves industries. Besides, the industrial processes and sustainability implications required are examined to render these productions. The tannery districts are characterized by a strong artisanal component in the productive processes and follow diverse geographical agglomeration rationales. Field visits and in-depth interviews were conducted in the local districts of Solofra (tanning), Grumo Nevano-Aversa (shoemaking), and Rione Sanità pole (glove-making). The local activities and specific operational industrial processes are mapped, highlighting the technical industrial phases needed to produce the three leather outputs. Besides, the sustainability repercussions of these industries are analyzed. The study finds that most of the activities heavily rely on traditional techniques and would benefit in socioeconomic and environmental terms from modernization, management, ICT upgrades, as well as process revisions and spatial agglomeration organization. Selected sectoral sustainable development, CSR, ESG, labeling, ethics, and environmental strategy recommendations are presented – especially concerning tanning wastewater treatment. These measures result in a compulsion to face the massive multidimensional crises occurring in the three sectors and business activities.

Following the Fish

Abstract This visual essay explores the Catalan exhibition Following the Fish/Toppi jën wi at the Venice Architecture Biennale (2023). The exhibition concentrates on the various geopolitical, economic, and historical forces that have driven many sub-Saharan migrants to flee their homes for the EU, placing them in complexly perilous sites of socio-legal-economic and cultural conditions, ones fraught with danger but also operating in hope with many lessons for EU cities and their civic, public spheres. The exhibition is a collaboration between the Barcelona architectural collective Leve and the organization Top Manta, a Barcelona collective and fashion design manufacturer that creates communal and legal opportunities for migrants who sell their wares on blankets in public squares.

Influence of More Mechanistic Representation of Particle Dry Deposition on 1850–2000 Changes in Global Aerosol Burdens and Radiative Forcing

AbstractRobust estimates of historical changes in aerosols are key for accurate constraints on climate sensitivity. Dry deposition is a primary sink of aerosols from the atmosphere. However, most global climate models do not accurately represent observed strong dependencies of dry deposition following turbulent transport on aerosol size. It is unclear whether there is a substantial impact of mischaracterized aerosol deposition velocities on historical aerosol changes. Here we describe improved mechanistic representation of aerosol dry deposition in the NASA Goddard Institute for Space Studies (GISS) global climate model, ModelE, and illustrate the impact on 1850–2000 changes in global aerosol burdens as well as aerosol direct and cloud albedo effects using a set of 1850 and 2000 time slice simulations. We employ two aerosol configurations of ModelE (a “bulk” mass‐based configuration and a configuration that more explicitly represents aerosol size distributions, internal mixing, and microphysics) to explore how model structural differences in aerosol representation alter the response to representation of dry deposition. Both configurations show larger historical increases in the global burdens of non‐dust aerosols with the new dry deposition scheme, by 11% in the simpler mass‐based configuration and 23% in the more complex microphysical configuration. Historical radiative forcing responses, which vary in magnitude from 5% to 12% as well as sign, depend on the aerosol configuration.

Characterizing the stress relaxation behavior of unidirectional prepreg through a parallel fractional-order viscoelastic model

In the hot-stamp molding and hot diaphragm forming processes of composites, pressure significantly influences shaping quality. This study establishes a novel parallel fractional-order viscoelastic (PFOV) model with two Scott-Blair elements, achieving remarkable accuracy (R2 = 0.99) with fewer parameters. Unlike traditional models, it incorporates the force history of prepreg, providing a more precise representation of its mechanical response. Comparative analysis against established models underscores its superior ability to capture intricate stress relaxation behaviors. Notably, the model’s reduced parameters enhance its physical interpretability, offering a significant advantage in simulating and predicting prepreg material compression behavior for diverse manufacturing processes.

Facing the Limitations of Teaching and Learning Committed to Solidarity and Social Justice: A Feminist Approach

This study examines how 52 graduate students enrolled in a social justice program in a large urban university in Canada relate to others in and outside the college classroom. Using a method involving creative student audio productions and self-reflections, the study finds that despite extensive learning about others and engaging with postcolonial, race, feminist, Indigenous and other critical theories and knowledges in the program, both racially privileged students and those who are members of disadvantaged and marginalized social groups enact relations extending power structures imagined as “solidarity.” These relations have important gender aspects and are shaped by broader historical forces, such as racism and colonization, as well as contemporary aspects of Canadian academia that have not been studied fully in relation to social justice education. These findings call for social justice curriculum and pedagogies that move learners from thinking critically and feeling empathy for others to behaving ethically and standing in political togetherness with those others as equals. The study suggests that transnational women and feminist political practices of solidarity mobilizing cross-racial and cross-national women’s movements in the 1970s, 1980s and 1990s present valuable pedagogies that could position college students for such relating.

Analyzing the Differences in the Concepts of Love Between Korean and American Women Using the Female Characters in Kim Ji-young, Born in 1982 and The Sun Also Rises as Examples

This paper scrutinizes the differences in the conceptualization of love between Korean and American women.Grounded in an analysis of literary figures, Brett and Kim Ji-young, the study unravels the intricate interplay of cultural, historical, and societal forces shaping these perspectives. The contrasting landscapes of the United States, driven by ideals of freedom and individualism, and Korea, entrenched in Confucian values and collectivism, serve as crucibles for forming women’s roles, self-perception, and societal expectations. The examination extends to communication styles, illuminating the directness of American expression versus Korea’s reliance on formalism. Through this exploration, the paper illustrates the profound impact of cultural contexts on the intricate tapestry of love, offering a nuanced understanding of divergent viewpoints within a global context.

Low‐velocity impact response of 3D carbon fiber reinforced polymer auxetic lattice structures

AbstractIn this paper, low‐velocity impact properties and impact damage responses of a novel type of 3D hybrid auxetic structures made from carbon fiber‐reinforced polymer (CFRP) laminates were investigated experimentally and numerically. The structures were first fabricated with three different rib's width ratios t1/t0, and then impacted with three different impact energies of 30, 40, and 50 J using a drop tower impact system equipped with a cylindrical impactor. The finite element (FE) models were built in ABAQUS/Explicit, and the Hashin criteria were applied to predict the failure of the structures. The contact force histories, energy histories, displacements, and failure modes were compared between the experiment and FE simulation at all three impact energy levels. The failure morphologies and mechanisms were obtained and studied. The impact testing results suggest that the 3D auxetic structure with a higher t1/t0 ratio can lead to higher peak contact force and sustain higher impact energy. The failure of the structure starts from the middle area and propagates to the upper and lower areas. This research provides a better understanding of the impact responses and failure modes of the 3D auxetic lattice structure, which can promote the potential applications of the auxetic materials.Highlights Drop weight low‐velocity impact responses of 3D novel hybrid auxetic lattice structures are investigated through both experiment and finite element simulation. The effects of structural parameters on the impact performance of the 3D auxetic structures at different impact energy levels are analyzed. The failure morphologies and mechanisms of the 3D auxetic structures are studied.

New model ensemble reveals how forcing uncertainty and model structure alter climate simulated across CMIP generations of the Community Earth System Model

Abstract. Climate simulation uncertainties arise from internal variability, model structure, and external forcings. Model intercomparisons (such as the Coupled Model Intercomparison Project; CMIP) and single-model large ensembles have provided insight into uncertainty sources. Under the Community Earth System Model (CESM) project, large ensembles have been performed for CESM2 (a CMIP6-era model) and CESM1 (a CMIP5-era model). We refer to these as CESM2-LE and CESM1-LE. The external forcing used in these simulations has changed to be consistent with their CMIP generation. As a result, differences between CESM2-LE and CESM1-LE ensemble means arise from changes in both model structure and forcing. Here we present new ensemble simulations which allow us to separate the influences of these model structural and forcing differences. Our new CESM2 simulations are run with CMIP5 forcings equivalent to those used in the CESM1-LE. We find a strong influence of historical forcing uncertainty due to aerosol effects on simulated climate. For the historical period, forcing drives reduced global warming and ocean heat uptake in CESM2-LE relative to CESM1-LE that is counteracted by the influence of model structure. The influence of the model structure and forcing vary across the globe, and the Arctic exhibits a distinct signal that contrasts with the global mean. For the 21st century, the importance of scenario forcing differences (SSP3–7.0 for CESM2-LE and RCP8.5 for CESM1-LE) is evident. The new simulations presented here allow us to diagnose the influence of model structure on 21st century change, despite large scenario forcing differences, revealing that differences in the meridional distribution of warming are caused by model structure. Feedback analysis reveals that clouds and their impact on shortwave radiation explain many of these structural differences between CESM2 and CESM1. In the Arctic, albedo changes control transient climate evolution differences due to structural differences between CESM2 and CESM1.

Historical changes in wind-driven ocean circulation drive pattern of Pacific warming

The tropical Pacific warming pattern since the 1950s exhibits two warming centers in the western Pacific (WP) and eastern Pacific (EP), encompassing an equatorial central Pacific (CP) cooling and a hemispheric asymmetry in the subtropical EP. The underlying mechanisms of this warming pattern remain debated. Here, we conduct ocean heat decompositions of two coupled model large ensembles to unfold the role of wind-driven ocean circulation. When wind changes are suppressed, historical radiative forcing induces a subtropical northeastern Pacific warming, thus causing a hemispheric asymmetry that extends toward the tropical WP. The tropical EP warming is instead induced by the cross-equatorial winds associated with the hemispheric asymmetry, and its driving mechanism is southward warm Ekman advection due to the off-equatorial westerly wind anomalies around 5°N, not vertical thermocline adjustment. Climate models fail to capture the observed CP cooling, suggesting an urgent need to better simulate equatorial oceanic processes and thermal structures.

Theoretical investigation of the free fall of a spherical particle in a viscous fluid using continuous piecewise linearization method

This article presents a theoretical investigation of the problem of free fall of a spherical particle in a viscous fluid. The classic Boussinesq-Basset-Oseen (BBO) model for particle motion in laminar flow was modified for generalized flow by using a drag law that is applicable for 0<Re≤2.0×105. By assuming that the acceleration in the Basset force integral is constant, the Basset force effect was approximated to form an integrated added mass coefficient. Consequently, the integro-differential equation of the BBO model was transformed to a first-order nonlinear ordinary differential equation that accounts for the Basset force effect and was solved using the continuous piecewise linearization method (CPLM). The CPLM algorithm was developed based on the jerk-velocity relationship and is applicable to zero and non-zero initial conditions, steady motion, increasing or decreasing velocities and the corresponding acceleration and jerk responses. The CPLM algorithm was shown to predict published experimental results accurately and compared very well with numerical solutions and existing analytical solutions. Examination of the fall response under varying parameters showed that the fall distance, fall time and terminal velocity depend strongly on the sphere diameter, sphere density, and the density and viscosity of the fluid medium. Also, an analytical solution for the power dissipated in the fluid medium as the sphere falls to reach its terminal velocity was derived. The power dissipated was found to increase exponentially as the initial velocity deviates positively from the terminal velocity.

Towards the definition of a solar forcing dataset for CMIP7

Abstract. The solar forcing prepared for Phase 6 of the Coupled Model Intercomparison Project (CMIP6) has been used extensively in climate model experiments and has been tested in various intercomparison studies. Recently, an International Space Science Institute (ISSI) working group has been established to revisit the solar forcing recommendations, based on the lessons learned from CMIP6, and to assess new datasets that have become available, in order to define a road map for building a revised and extended historical solar forcing dataset for the upcoming Phase 7 of CMIP. This paper identifies the possible improvements required and outlines a strategy to address them in the planned new solar forcing dataset. Proposed major changes include the adoption of the new Total and Spectral Solar Irradiance Sensor (TSIS-1) solar reference spectrum for solar spectral irradiance and an improved description of top-of-the-atmosphere energetic electron fluxes, as well as their reconstruction back to 1850 by means of geomagnetic proxy data. In addition, there is an urgent need to consider the proposed updates in the ozone forcing dataset in order to ensure a self-consistent solar forcing in coupled models without interactive chemistry. Regarding future solar forcing, we propose consideration of stochastic ensemble forcing scenarios, ideally in concert with other natural forcings, in order to allow for realistic projections of natural forcing uncertainties.

An efficient impact force identification methodology via a single sensor utilizing the concept of generalized transmissibility

The issue of localizing and reconstructing the impact force through double-inverse approaches is widely recognized as an ill-posed and computationally demanding problem. Such a challenge has emerged as a prominent research topic of interest and great concern in the field of structural health monitoring. This study proposes a novel and efficient hierarchical methodology that is adept at ascertaining both the location and time history of an impact force through data obtained from a single accelerometer. The proposed methodology entails an efficient retrieval of uncorrected modal constants with a ratio function referred to as generalized transmissibility. The generalized transmissibility symbolizes the ratio of responses from identical accelerometer subjected to two distinct impacting scenarios, one excited at a yet-to-be-identified location and the other at a pre-determined reference location. The theoretical disclosure of the correlation between the generalized transmissibility at pole frequencies and retrieved uncorrected modal constants is demonstrated in details herein. These modal constants are then served as a signature to identify the impact location. Following localization, the force reconstruction problem is tackled by fitting a parametric model, wherein a gaussian basis function is employed to effectively approximate the time history of impact force. Experimental demonstrations on a metallic plate and a composite wing were carried out to validate the efficient and accurate localization as well as the rapid reconstruction capabilities in response to an impact force applied anywhere on a 2D structure.

Orthodox Jewish anti-LGBTQ+ ideologies, with implications for clinical practice with Orthodox Jewish LGBTQ+ persons

ABSTRACT Lesbian, gay, bisexual, transgender, queer, questioning, and other sexual and gender minority (LGBTQ+) clients experiencing conflict over personally-held conservative religious beliefs benefit from their clinicians’ having knowledge of their movements’ specific anti-LGBTQ+ ideologies. This paper examines anti-LGBTQ+ ideologies found in Ultra-Orthodox, and Modern Orthodox Judaism. Orthodox Jewish anti-LGBTQ+ ideologies are impacted by historical and intellectual traditions, their adherents’ privileged or oppressed positions in society, their institutions’ relationships to national and global politics, and various historical, social, and economic forces that they help their adherents face. Orthodox Jewish institutions are also associated with certain benefits of staying and costs of leaving, which may draw LGBTQ+ persons to remain involved with them despite having to cope with an intolerant milieu. We suggest classic theories of rational choice, identity development, and religious judgment as ways of understanding and working with LGBTQ+ persons experiencing conflict over personally-held Orthodox Jewish ideas.

Physics-informed deep learning for scattered full wavefield reconstruction from a sparse set of sensor data for impact diagnosis in structural health monitoring

This paper presents a physics-informed deep learning framework for the reconstruction of full scattered spatiotemporal Lamb wavefields (video images) in plate-like structures from a sparse set of time-series sensor data. The reconstructed scattered wavefield contains a wealth of information about the wave propagation phenomenon including any interactions of the propagating wave with damage in the structure. This information is paramount for damage diagnosis as is demonstrated in this paper via impact diagnosis—a key structural health monitoring application. A physics-informed neural network (PINN) that encodes the underlying elastodynamic field equations into the learning/training process in the neural network is proposed for this purpose. This prior wavefield physics knowledge embedded in the loss function acts as a regularization agent for the minimization problem in the neural network training, thereby enabling the extrapolation of a sparse set of one-dimensional time-series signals into two-dimensional scattered wavefield. The wavefield reconstruction capabilities of the proposed supervised forward PINN framework are first verified both numerically and experimentally for a stiffened aluminum panel under a couple of narrowband ultrasonic-frequency excitations, and the results confirm its robustness to low spatial resolution and substantial noise in the measured sensor data. The PINN requires far fewer sensors for scattered wavefield reconstruction, thereby permitting for a higher sensor spacing or lower spatial sampling. To this end, it is shown that a sensor spacing of 5λ generates good wavefield reconstruction accuracy, which is a 10-fold increase over the Nyquist–Shannon sampling limit (λ/2). Two sets of experiments are then conducted on a long-stiffened aluminum panel to validate the proposed framework via low-velocity impact diagnosis in the near-ultrasonic frequency range. The first set of experiments, with the known excitation force incorporated into the PINN, allows the wavefields to be accurately reconstructed with the sensor spacing up to 5λ as expected. The second set of experiments assumes unknown impact force history—a classical case of impact diagnosis where the impact force history is not known a priori. It is shown that the wavefield reconstruction through PINN still provides good accuracy albeit with a less generous sensor spacing of 2λ. A convolutional neural network long short-term memory (CNN-LSTM) model then solves the mathematically inverse problem of inferring the impact location and impact force history by analyzing the reconstructed impact generated wavefield. The impact location is predicted well with 93% accuracy, and the impact force history is reconstructed with 90% accuracy, further validating the proposed framework.

Проблема движущих сил исторического процесса и ее значение для философии истории: методологический аспект

Introduction. The work one of the main problems of the philosophy of history — the problem of the driving forces of the historical process. The author identifies specific driving forces of history, put forward in historiosophy. The methodological aspects of the formation of the philosophy of history as a whole, determined by the problem of the driving forces of history, are shown. The purpose of the article is to show driving forces issue in forming the problem field of historiosophy. Methods. The author uses the following general scientific methods: modeling, structural-functional, systemic and comparative analysis; movement from abstract to concrete and from concrete to abstract. Scientific novelty of the research. The author identifies problems existing in the philosophy of history and gives an analysis of these problems. The author shows that the one of the most important problem that integrates other historiosophical issues is the problem of the driving forces of history. The specific driving forces of history are identified and analyzed in historiosophy. It is shown that, methodologically, the problem of driving forces in history plays a special role in the philosophy of history in a number of aspects: conceptual, integrative, test, and the aspect of complementarity. Results. The author shows that the problem of driving forces in history solves a number of problems in historiosophy. Firstly, each specific driving force makes it possible to create new theories in the philosophy of history. Secondly, it forms a special picture of historical dynamics. Thirdly, it allows us to consider various factors of history as the main ones in a system of other parameters, thereby finding their true place in analyzing the historical process. Fourth, it demonstrates the need to jointly analyze various driving forces to create a common historical picture. Conclusions. The work examines only a few specific driving forces of history, but they must continue to be identified. The author has identified four aspects that reveal the special methodological role of the driving forces problem of history in historiosophy. In fact, more of them can be identified.

Iran’s Proxy War Strategy

This article analyzes Iran’s Shia Imamate project that shapes its proxy war strategy. The Islamic Republic of Iran’s (IRI) indirect surrogate warfare doctrine is discussed in three stages. First, the historical forces behind Tehran’s proxy war approach and ideological factors that drive it are analyzed. Second, the historical execution of its militia strategy is examined; and third, the consequences of the Iranian-Hezbollah military entrenchment in Syria and its impact on the October 2023 Gaza War are assessed. The author concludes that Iran and its Shia proxies are poorly positioned to sustain a regional war against Israel to save Hamas.

Salvation Through Womanhood: The Doctrine of Woman Leadership and Portrayal of Ko P'allye as the Great Mother in Chŭngsando

Abstract: The South Korean religion of Chŭngsando places pronounced emphasis on women by teaching that their emancipation is a precondition for surviving an apocalyptic transition, whereafter gender inequities will end. It further highlights the role of historical personage and mother, Ko P'allye (1880–1935), in the early history of the Chŭngsan movement as having been an active subject and the religious successor to male founder, Chŭngsan Kang Ilsun (1871–1909). This doctrine, and Chŭngsando's scriptual portrayal of Ko are explicitly challenging to traditional and contemporary patriarchy, yet it is Chŭngsando's current male leader, An Kyŏngjŏn, who has elevated these elements to a greater degree than any other sect. This article examines representations of womanhood and motherhood within Chŭngsando's current scripture through a close reading of the gendered aspects of the doctrine and portrayal of Ko P'allye. While addressing the textual history, it approaches the scripture as a cultural text for which the most recent version offers the richest elaboration. It analogizes to popular culture to interpret a core characteristic of the text: interplay of the mundane (historical reality) and the extraordinary (religious content). It meanwhile historicizes the tensions with structural patriarchy by situating the Chŭngsan religion as a subaltern salvationist movement. I argue the doctrine and portrayal are neither invention nor contradictory to the movement but trace to two historical forces: emancipatory discourse(s) of women, and Ko's own lived reality as a subaltern.

Numerical study on wind-loading characteristics of a high-speed train running over the bridge under tornado-like vortices

With global warming intensifying, weather patterns become more volatile and extremes more common. Tornadoes are the most destructive natural disasters causing significant damage to infrastructure. Meanwhile, high-speed railways now face greater risks from tornado events as the national railway network and mass transit trains expand. Thus, studying the tornado flow characteristics and associated effects on high-speed trains is necessary. A study is presented regarding the wind-loading characteristics of a high-speed train running over a railway bridge induced by a tornado belonging to the future railway network. The wind-loading characteristics analyses are performed using the improved delayed detached eddy simulation method. After verifying the numerical approach and mesh strategy, computational studies are conducted to produce a tornado-like vortex and investigate the tornado-induced wind-loading characteristics of a high-speed train running on the bridge by combining a tornado simulation with a moving mesh technique. For the wind-loading parameters studied herein, the selected train's velocity range is between 50 and 350 km/h, the typical operation speed of either regular or high-speed trains. The numerical results show that the time histories of aerodynamic forces on the train revealed a pattern in tornadic flow variability, the time evolutions of the wind loads on the train were affected by train speeds, and the fluctuation was the greatest when the train ran at 50 km/h. Moreover, the train is subjected to larger aerodynamic forces and moments when it operates along with the rotating vortex flow, especially in the core region, and the train is more dangerous when it runs at a lower speed. The results in this study provide references for assessing operation safety, while a train running on the bridge encounters tornadoes.