Moment Of Opening Research Articles

Performance of nodal regions of reinforced concrete frame corners subjected to opening bending moments

Design of frame corners in presence of opening moments is a task that has concentrated many research and engineering efforts in the past. It deals with the response of discontinuity regions, where beam theory does not hold valid and the use of equilibrium-based models (such as strut-and-tie models or stress fields) could be a suitable manner to understand the transfer of forces and to lead to consistent reinforcement detailing. However, the assessment of efficiency factors for equilibrium-based models is not straightforward for such details as their response has been observed to be governed in many cases by the tensile resistance of concrete and crack propagation. Furthermore, most efforts so far have been devoted to determining only the resistance of the region as a function of its reinforcement detailing, but limited works have been dedicated to their post-peak response. The post-peak response is nevertheless instrumental for redundant structures, as it governs the level of potential redistributions of internal forces in order to develop the full structural resistance of the system. Such aspect has become even more significant in present days, where the assessment of existing structures with potentially poor nodal detailing has become a need to avoid unnecessary retrofitting or replacement, in an effort to reduce carbon footprint of construction. In this paper, comprehensive research on this topic is presented. It is based on the results of a large database compiled by the authors comprising 126 tests. After filtering of the database, conclusions on the expected response of several details are obtained. Also, a general procedure grounded on an equilibrium-based model is proposed, providing tailored efficiency factors as a function of the mechanical reinforcement ratio and detailing type, but also providing a complete description of the post-peak response. This latter model is based on a kinematically-compatible displacement field for the post-peak phase, allowing to evaluate the opening of the cracks in the nodal region and the associated softening of resistance.

Moment Capacity of Bolted-Side Plate for the Eaves Joint of Nested Tapered Box Beam Portal Frame

The joints of cold-formed steel (CFS) portal frames with box sections are primarily formed either through stiffened welded connections or by bolted end plates, which typically involve costly full penetration butt welds. In New Zealand, CFS portal frames with nested tapered box beam (NTBB) sections are popular, and the joints of these portal frames are also formed through a bolted end plate system. In literature, it was found that welds in these joints are prone to cracking in the heat-affected zone (HAZ) under bearing opening moments (tension). Therefore, this paper focuses on proposing an alternative connection system (bolted-side plate) for eaves joints without any weld, aiming to reduce the overall cost of construction and increase construction speed. The performance (strength and stiffness) of these joints is mainly dependent on the geometric details of the bolted-side plate, which is limited in Australia/New Zealand standards (AS/NZ 4600). Herein, a non-linear finite element (FE) model was developed for the NTBB portal frame and validated against the experimental test results from the literature. Firstly, the validated FE model was used to investigate the feasibility of using bolted-side plates for NTBB portal frames and found that the bolted-side plate can increase the ultimate capacity of NTBB portal frame by 9%. A parametric study was then conducted by considering different geometric details of the bolted-side plates under both closing (gravity) and opening (wind uplift) moments. Finally, unified design equations for the moment capacity of bolted-side plates were proposed based on the results of the parametric study, and their accuracy was assessed through reliability analysis.

Damage analysis in welded steel pipe elbow under strong cyclic loading

According to cyclic loading modes, highly pressurized tubular elements, such as those in elbows, differ from other straight tubular structures in their modes of stress and damage. This work aims to perform a numerical prediction of a tubular structure. It consists of an X52 steel elbow welded to X65 grade ends by straight tubular sections. This pressurized structure is subjected to strong cyclic loading in bending moment applied until damage occurs. The bending moment is combined with different orientations between the closing or opening moment and the out-of-plane moment, presenting a possible but rarely analyzed situation. This cyclic loading mode is taken as an evaluative parameter in its various amplitudes, orientations, and patterns. The cyclic hardening of the elbow and straight tubular sections, including those of the welded joints, are all formulated by the combined isotropic and kinematic model introduced in the ABAQUS calculation code with parameters calibrated according to the Voce model and experimental results, using plasticity by the Von Mises equivalent stress flow theory. The appropriate XFEM (Extended Finite Element Method) technique is used in conjunction with the hardening model to overcome numerical calculation difficulties and predict damage in traction laws, separation by crack initiation and propagation. The results, in the form of hysteresis curves in cyclic bending moment and angular displacement, have shown a strong dependency that conditions the structure’s response as well as the level of its damage.

Finite Sequences Representing Expected Order Statistics

Characterizations of finite sequences β1<⋯<βn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta _{1}<\\cdots <\\beta _{n}$$\\end{document} representing expected values of order statistics from a random sample of size n are given. As a by-product, a characterization of binomial mixtures, when the mixing random variable is supported in the open interval (0, 1), is presented; this enables the exact description of the convex hull of the open binomial curve, as well as the open moment curve.

Labour in Fisheries Through Migration Studies: Burmese Fish Worker Regularisation and Agency in the Thai Fishing Industry

ABSTRACT In recent years, labour in fisheries has emerged as a field of study, gaining traction both from academics and through policy implementations. Fish workers often migrate across jurisdictional borders to work on industrial fishing boats around the world. I argue that research on labour in fisheries would benefit from the inclusion of concepts found within migration studies that can unpack the implications of being a migrant in a host country. In this paper, I borrow the concepts of ‘regularisation’ and ‘migrant agency’ from migration studies to examine how migrant fish workers navigate migration regimes in order to work in the offshore fishing industry. I illustrate my argument through a case of Burmese fish workers in the border city of Ranong, Thailand. Methodologically, I focus on three disruptions to Thai fisheries – labour regulatory reforms, the pandemic, and the recent military coup in Myanmar, in 2021—as open moments to explore ways in which Burmese migrant fish workers navigate their livelihood strategies. Regularisation highlights the trade-off between the benefits and the costs for migrant fish workers of gaining legal status during the disruptions. The concept of migrant agency provides a lens through which to capture how migrants explored the space of possibilities through the cultivation of ethnicity and digital technology during the disruptions. I conclude that theoretically drawing on concepts found within migration studies has the potential to reveal the complexity of migrant fish workers, who exercise their agency, rather than being understood as mere victims in the unruly nature of ocean governance.

Transient-state modeling and thermodynamic analysis of self-pressurization liquid hydrogen tank considering effect of vacuum multi-layer insulation coupled with vapor-cooled shield

The transient-state model of self-pressurization of liquid hydrogen tank is constructed. It consists a heat and mass transfer model of fluid domain and a heat conduction model of VMLI (vacuum multi-layer insulation) coupled with VCS (vapor-cooled shield). The vapor consumption factor λv, the dormancy extension factor λd and the unit factor λ are defined. λv is the ratio of vapor consumption with the initial hydrogen mass in tank, and λd is the extension of the dormancy with VCS opened relative to that with VCS closed, and λ is the efficiency of VCS shielding heat leakage. The effects of the mass flowrate in VCS, λv, dimensionless position of VCS, opening moment of VCS on λd and λ are investigated. The results show that, when λv and the operating time of VCS are fixed, the best dimensionless position of SVCS (single vapor-cooled shield) and DVCS (double vapor-cooled shield) that maximizes λd is 0.622 and (0.333,0.644) respectively. Under condition that the duration time of VCS and λv are fixed, for SVCS and DVCS, the best opening moment that maximizes λd is observed to be day 23.26 and day 34.84 respectively, and the maximum of λd with DVCS is 29.5 % larger than that with SVCS.

When, where, and how can land governance overcome path dependency? A trajectory of land governance change

Land governance deals with the intersections of policies, processes, and institutions on access, use, and interest in land and its resources. Path dependence on land governance can lead to unsustainable land control, shaping people’s livelihoods and well-being. Agency in land governance is well explored. The link between actors, their aims, and their agencies for transformative action has been established. However, these concepts have not sufficiently explained why land governance change can happen. Why certain governance is preferred over others is still open for interpretation. To address this gap, we incorporate insights from the social-ecological systems (SES) and socio-technical systems (STS) studies and add timing and strategic structures in analyzing the transformation process in land governance literature to build a trajectory of land governance changes that indicate ways out of the path dependency in land governance. The trajectory has scholarly novelty in adding ‘where’ (leverage points) and ‘when’ (triggers) to the existing strategic aspects of ‘who’ (actors) and ‘how’ (agency), and linking the four to indicate ways out of the path dependency. The agency of change in land governance emerges only when certain triggers destabilize incumbent land governance. Agencies and leverages are interrelated. Failure to gather momentum leads to inefficient utilization of design leverage, dropping key actors into a barrier of change, wasting the open moment, and missing the opportunity for change.

Development and Implementation of a RC Snubber to Suppress Breaker Arcing Present in High-Stored-Energy Superconducting Magnet Systems

Arc suppression Snubbers offer safety in high energy superconducting magnet systems. Large superconducting magnets may have arcing across their breakers at the moment of slow dump initiation resulting from a sudden current redistribution in the powering circuit. The ATLAS Experiment at CERN experiences such arcing with its 7.3 H Toroidal magnet powering circuit. To discharge the magnets, the current is redistributed to a parallel branch called the Run Down Unit (RDU) by means of a breaker. Due to the physical layout and other metallic components in the vicinity, the power supply and RDU branches have undesirable and unavoidable parasitic inductance, causing a voltage spike over the main breakers at the moment of opening. The resulting arcing deteriorates the breaker contacts, resulting in increased operating temperatures and a more frequent need for maintenance. The arc suppression system developed takes the form of an RC Snubber (Resistor-Capacitor). The Snubber offers the current a low-impedance path, thus smoothing out the current redistribution and suppressing the voltage spike. This initial charging period of the capacitors gives the current enough time to overcome the parasitic inductance, therefore allowing the RDU to smoothly ramp up without a sudden voltage spike. To test the concept, a 1/50th scale demonstrator was developed and showed successful results. After the demonstrator, endurance testing of the electrolytic capacitors was performed to ensure no degradation of the charging characteristics for an equivalent of 20 years of operation. The Snubber was manufactured and implemented with successful results on the ATLAS Toroidal powering circuit.

Paratexts as Portals

In an understudied cluster of films from the 1920s in Spain that feature the tumultuous lives of female music-hall entertainers, posters, postcards, and magazines not only mirror the shape of windows, doors and thresholds, but also direct the flow of circulating images of women. These portable, paper media immobilize or propel women’s bodies into motion, constituting portals that enable or disrupt fame, security and “happiness.” Rectangular artifacts both don the walls, windows, and cabinets in these films' mise-en-scène, and drive the story, character development, and the production of gender and racial identity. These films show characters interacting with posters, postcards, and magazines in a way that becomes as determining as the gripping plots, enabling women to pivot between stark, atavistic, or impoverished rurality and electrifying urban spaces. In this article, I examine the governing status of paratexts and the female star image in early Spanish film culture by tracing the history of La gitana blanca, a film directed by Ricardo de Baños initially released in 1919 and then reedited and redistributed internationally in 1923. In its opening moments, La gitana blanca offers us a view into how paratexts not only saturated the media ecology of the 1920s but also were “responsible for popular culture’s encounters with countless story worlds.” In the context of Spanish film historiography’s master narratives, in which cultural hierarchies remain tightly enmeshed with gendered and racialized logics, a cross-media perspective proves instrumental in revealing the extent to which film culture mediated the real and fictive lives of women.

Behavior of reinforced concrete stair slabs strengthened with steel plates and near surface mounted steel bars

The bends in Reinforced Concrete Stair Slabs (RCSS) subjected to opening moments may be damaged due to improper detailing of tensile reinforcement or construction errors. The damaged bends in RCSS need to be strengthened to restore their flexural strengths. However, there are very limited investigations into the behavior of strengthened RCSS. This paper reports experimental and simulation works on the structural behavior of RCSS strengthened with externally bonded steel plates and near surface mounted steel bars. The test program and results of six full-scale strengthened RCSS loaded to failure are described in detail. A finite element model is developed using ABAQUS to simulate the experimentally measured responses of strengthened RCSS. It is shown that the utilized strengthening techniques significantly improve the cracking load, ultimate load, and energy absorption capacity of RCSS. There is a good agreement between computer simulations and experimental results, suggesting that the model of nonlinear inelastic analysis can be used with confidence to conduct further parametric studies.

Moment capacity of eaves brackets of cold-formed steel portal frames

The strength and stiffness of cold-formed steel portal frames are heavily related to the performance of their joints; these joints are normally formed through brackets, bolted to the webs of channels. Previous research in the literature has considered the strength of the apex bracket, and design equations proposed to predict its moment capacity. No similar research, however, has been undertaken for the eaves bracket. In the literature, the only design guidance found is a design chart, limited to eaves joints fully restrained against lateral torsional buckling, for use under a closing moment and an eaves bracket details having a stiffener along its hypotenuses. This paper describes a finite element study comprising 7,560 models, that addresses all these limitations. Unified equations are presented that can be used for the design of eaves brackets in practical partially restrained eaves joints, as found in New Zealand practice, both closing and opening moments, and different arrangements of stiffeners in the detail of the eaves bracket.

“What’s your name?”

Abstract This study investigates the role of identification and frame mismatch in Korean telephone call openings using conversation analysis on a series of problematic telephone calls made to the emergency center from a Korean governor (Moon-Soo, Kim) in 2011. Close examination of the problematic interaction indicates how delivering emergency care as a public service may evolve into a dispute in the Korean cultural context of kwandungsengmyeng (“identifying oneself by official status”). A mismatch between frames (Tracy, 1997) can be identified when the governor asks for the name of the answerer instead of presenting the reason for the call. Comparable examples from Korean conversational telephone calls are noted in which the answerer provides their name in the opening moments of the interaction, thereby depicting a strong expectation for identification and recognition in Korean openings. This paper argues that the governor’s actions can be explained by a mismatch between the public and private frames in relation to identification practices. The study findings may highlight the important role that identification and recognition plays in Korean culture and suggest methods through which future problematic emergency calls can be prevented.

Numerical characterisation of the rotational behaviour of grey cast iron tunnel joints

The structural assessment of segmental grey cast iron (GCI) tunnel linings to nearby construction is challenging due to the presence of the joints affecting the stiffness of the tunnel lining. This paper presents an extensive investigation, using 3D finite element (FE) analyses, into the bending moment-rotation (M-θ) behaviour of two GCI tunnel joint geometries. These two geometries correspond to standard running and station tunnels of the London Underground network. The contribution of this study is two-fold. i) The novel characterisation of the M-θ response enables the development of new models for simulating the mechanical response of GCI tunnel joints with structural elements which can be used in simplified, 2D geotechnical analysis for tunnel safety assessments. ii) The analyses provide insight into the behaviour of GCI tunnel linings that would be difficult to achieve through experimental and field observations alone. More specifically, the analyses show that when the bolts are removed from the joints the possibility of tensile failure can be disregarded; that the initial bolt preload influences the rotational stiffness only after some rotation has taken place and does not alter the bending moment of opening; and that the out-of-plane displacement restraint has little influence on the joint response.

The role of the escrow account agreement in the squeeze-out procedure

The article is devoted to the analysis of an escrow agreement. The legal regulation of this contract is determined in the Civil Code of Ukraine. The specified contractual construction is also applied within the squeeze-out procedure, i.e. the mandatory sale of shares by shareholders at the request of a person (persons acting jointly) who is the owner of a dominant controlling block of shares. The research argues that the norms of the Law of Ukraine "On Joint Stock Companies" contain separate provisions regarding the escrow account and are essentially special in relation to the prescriptions of the Civil Code of Ukraine.&#x0D; It was established that the parties to the escrow agreement are the account holder, the beneficiary and the bank. Within the squeeze-out procedure defined by Art. 95 of the Law of Ukraine "On Joint-Stock Companies", the owner of the escrow account is the applicant of the public irrevocable claim, while the shareholders whose shares are subject to redemption are the beneficiaries and have the right to receive funds from the escrow account. Beneficiaries under the escrow agreement may also be the legal assignees of such shareholders or other persons who, in accordance with the law, has the right to receive funds. It is substantiated that in the analyzed contractual structure the bank performs the role of an independent party, an escrow agent trusted by both parties.&#x0D; It is emphasized that the moment of opening an escrow account in the squeeze-out procedure and the term of depositing funds into it are clearly separated at the legislative level. The second one is closely related to the time limit for submitting a competing claim specified by the Law. The advantages and disadvantages of using this approach in national legislation are characterized.&#x0D; The changes that have taken place in the national legislation regarding the escrow agreement in connection with the adoption of the Law of Ukraine "On Joint Stock Companies" in 2022 have been analyzed. Attention has been drawn to the increase of the period during which the bank, in which the escrow account is opened, is obliged to make payments to the beneficiaries due to them.

The emotional life of rupture at Cambodia's Lower Sesan 2 hydropower dam

This article aims to extend and deepen our understanding of how emotions figure in experiences of major nature-society disruptions or “rupture.” Cambodia's Lower Sesan 2 hydropower dam is an example of rupture, which refers to dramatic, adverse, and disruptive episodes that ripple across scale. Against a historical backdrop of land enclosures and dispossession, the dam sparked significant community and civil society resistance. This emotionally charged campaign emphasized that the dam and associated resettlement would erase the impacted communities’ deep customary relationships to the area. Although some community members ultimately refused the resettlement package and moved to customary lands near their flooded village, the majority accepted resettlement. We explore the emotional dimensions of these communities’ experiences, finding that rupture is an inherently emotional process, within layered historical processes of change and violence. The intense emotions that such processes evoke can spark action within the “open moment” (Lund, 2016) that episodes of rupture create; yet the outcomes are highly unpredictable within the asymmetrical political and economic settings that underpin nature-society rupture.

‘Openness in Action’ Early Steps in Cosmic Phenomenology

‘Openness in Action’ Early Steps in Cosmic Phenomenology

Moment capacity of apex brackets of cold-formed steel portal frames

The strength and stiffness of cold-formed steel portal frames are heavily related to the performance of their joints; these joints are normally formed through brackets, bolted to the webs of channels. They should have adequate strength to ensure the frame fails within the members, and the design moment capacity of a joint should be equal to or exceed the moment to which the joint is subjected. For apex brackets, based on the results of a non-linear elasto-plastic finite element study, the authors have recently proposed design guidance in the form of equations for predicting the moment capacity. However, this prediction was limited to fully restrained apex joints against lateral torsional buckling, which is an arrangement not commonly used in practice. Furthermore, the joints considered were composed of back-to-back brackets connecting back-to-back channels. The design recommendations were further limited to apex joints under bearing gravity load, equivalent to the opening moment applied to the bracket. This paper extends the previous work by now considering both single and double apex brackets, which are partially restrained, consistent with New Zealand practice, and considering both opening and closing moments on apex joints (or gravity and wind uplift load on portal frames). This study proposes unified design equations from a parametric study comprising 5,040 finite element models.

Trajectories, bifurcations and hysteresis in the Argentine economic cycle: the economic policy of Sudden Stops

This paper analyzes the evolution of the Argentine gross domestic product between 1875-2010. It intends to analyze its trajectory over time according to the periods of greater or lesser economic integration that the country experienced. An explanation of the poor performance that occurs between 1970-2010 (second globalization) is presented and compared with the period 1885-1914 (first globalization). This paper presents a series of graphic arguments that will allow us to analyze the evolution of the Argentine gross product from 1885 to 2010. It is not intended to explain or investigate the specific causes or reasons for the prosperity or depression that Argentina experienced in each of its episodes. Instead, an attempt is made to present longterm stylized facts seeking to compare moments of opening versus those of a closed economy over which the country oscillated in order to analyze long-term growth and economic volatility.

A double-break current injection vacuum DCCB: Principle and analysis

To improve the breaking performances of current injection vacuum DC circuit breaker (DCCB), a double-break current injection DCCB proposed. The opening moments of the two breaks are not simultaneously, one of the breaks is arc breaking, which is used for cut off the fault current, and the other is non-arc breaking, which is used to enhance the transient recovery voltage (TRV) withstand capability. During the interruption process, let the arc-breaking contact first open, the contact starts to separate and produce arcs, then the pre-charged capacitor injects a reverse current to extinguish the arc, meanwhile, the current commutation of non-arc-breaking contact is realized by a coupling inductor. In addition, freewheeling diodes connected in parallel at the contacts to delay the occurrence of transient recovery voltage, thereby further increasing the voltage withstand capability of the CB. The principle and analysis of proposed DCCB scheme are discussed. Finally, the effectiveness of the proposed DCCB scheme is verified by simulation

Numerical Analysis of Mechanical Behavior of Self-Centering Joint between CFDST Column and RC Beam

The existing connection between the concrete-filled double steel tubular (CFDST) column and the reinforced concrete (RC) beam is difficult to repair and reuse after damage. In this paper, a self-centering joint between the CFDST column and the RC beam is proposed. The self-centering of the joint is realized by prestressed steel strands, and the energy dissipation is realized by friction. The overall purpose of the research is to analyze the influence of steel strand and friction on the mechanical behavior of the joint. By comparing the envelope curve and the restoring force model of a numerical joint model with theoretical values, accuracy of the numerical model was verified. Then, joints with different parameters, including the friction, prestress of steel strands, and ratio of the resisting moment provided by steel strands to the resisting moment provided by friction in the opening moment of joints, were numerically analyzed. The results showed that the joints with greater friction and prestress of steel strands had higher bearing capacity. Increasing the friction could increase the energy dissipation capacity of the joint, but it would increase the residual deformation of the joint. To reduce residual deformation, the prestress of steel strands should be increased. When the resultant force of the pretension of steel strands was greater than friction, the steel head could be kept pressed on the connecting block, making the stress changes of steel strands and the self-centering performance of the joint stable.