89 research outputs found
Promises and pitfalls of the Belt and Road Initiative
No full textFor more about the East-West Center, see http://www.eastwestcenter.org/Bipul Chatterjee and Saurabh Kumar, Executive Director and Policy Analyst, respectively, at CUTS International, explain that “China may accrue significant benefits if it reduces tariffs through free trade zones, particularly on products from BRI countries.
Interaction of VVO2−hydrazonates with lysozyme
No full textVanadium compounds (VCs) exhibit a broad range of pharmacological properties, with their most significant medical applications being in the treatment of cancer and diabetes. The therapeutic effects and mode of action of VCs may be associated with their ability to bind proteins and, consequently, understanding the VC–protein interaction is of paramount importance. Among the promising VCs, the VVO2 complex with the aroylhydrazone furan-2-carboxylic acid ((3-ethoxy-2-hydroxybenzylidene)hydrazide, hereafter denoted as VC1), deserves attention, since it exhibits cytotoxicity against various cancer cell lines, including HeLa. The interaction between VC1 and its analogue, denoted as VC2 (the dioxidovanadium(V) complex with (E)-N′-(1-(2-hydroxy-5-methoxyphenyl)ethylidene)furan-2-carbohydrazide), and hen egg white lysozyme (HEWL) was examined by UV–vis spectroscopy, fluorescence, circular dichroism, and X-ray crystallography. The interaction of VC1 and VC2 with HEWL does not alter the protein secondary and tertiary structure. Crystallographic studies indicate that the two metal complexes or V-containing fragments originating from VC1 and VC2 bind the protein via non-covalent interactions. Furthermore, when bound to HEWL, two VC1 molecules and two VC2 molecules form a supramolecular association stabilized by stacking interactions. This type of interaction could favour the binding of similar compounds to proteins and affect their biological activity
Trade and Food Security
No full textThe evolving food security agenda offers governments a chance to address some urgent concerns and strengthen the multilateral trade system. The Doha Agenda has been overtaken by time and events. Many of the lessons for food security of the past decade point to the need for new rules. International markets have seen three food commodity price spikes, and the financial collapse of 2008 and the resulting turmoil in international trade and financial markets has left its mark. Governments have been reluctant at the World Trade Organization to confront the implications of these changes. Many developed countries are advocating a “new” trade agenda (around investment, stronger intellectual property rights, and services), which are contentious issues for most developing countries. Most developing countries insist that nothing new should be added to the negotiating agenda until the Doha Agenda (in some form) is agreed. The impasse has yet to be resolved. Yet there are quite a few issues on which governments could advance if they were to focus on confidence-building, and ensuring that they can protect their food security interests while working within a multilateral trading system
Lateral resistance of pipes and strip anchors buried in dense sand
No full textThe response of buried pipes and vertical strip anchors in dense sand under lateral loading is compared based on finite-element (FE) modeling. Incorporating strain-softening behaviour of dense sand, the progressive development of shear bands and the mobilization of friction and dilation angles along the shear bands are examined, which can explain the variation of peak and post-peak resistances for anchors and pipes. The normalized peak resistance increases with embedment ratio and remains almost constant at large burial depths. When the height of an anchor is equal to the diameter of the pipe, the anchor gives approximately 10% higher peak resistance than that of the pipe. The transition from the shallow to deep failure mechanisms occurs at a larger embedment ratio for anchors than pipes. A simplified method is proposed to estimate the lateral resistance at the peak and also after softening at large displacements.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
Large-strain finite element analyses of a retrogressive landslide triggered by pile driving in sensitive clays: The Case of the 1978 Rigaud landslide in Québec
No full textA retrogressive landslide triggered by pile driving in sensitive clays in Rigaud, Quebec, is analyzed. The article presents the landslide characteristics, post-failure assessments, and potential failure mechanisms. To gain deeper insights into the triggering and propagation of failure, large-strain finite element (FE) modelling was conducted using a Eulerian-based FE approach. The FE simulations reveal that pile installation can induce localized shear band formation, ultimately leading to a large-scale landslide without the need for additional external loading. Key factors influencing the failure pattern include soil stratification, sensitivity, and the rate of post-peak shear strength degradation. The numerical modelling effectively replicates the observed field behaviour of the landslide, capturing crucial aspects such as retrogression distance, failure pattern, and the downslope displacement of failed soil masses. Although the landslide involved complex three dimensional effects and triggering conditions, the current two-dimensional large-strain FE simulations under plane strain conditions provide valuable insights into the underlying progressive failure mechanisms—insights that cannot be obtained using traditional limit equilibrium and conventional FE analyses. These findings underscore the significant role of pile driving in initiating landslides in sensitive clays and highlight the necessity of advanced numerical approaches to accurately predict and mitigate such failures.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Large deformation finite-element modelling of earthquake-induced landslides considering strain-softening behaviour of sensitive clay
No full textLarge-scale landslides in sensitive clays cannot be explained properly using the traditional limit equilibrium or Lagrangian-based finite-element (FE) methods. In the present study, dynamic FE analysis of sensitive clay slope failures triggered by an earthquake is performed using a large deformation FE modelling technique. A model for post-peak degradation of undrained shear strength as a function of accumulated plastic shear strain (strain-softening) is implemented in FE analysis. The progressive development of â shear bandsâ (the zone of high plastic shear strains) that causes the failure of a number of soil blocks is successfully simulated. Failure of a slope could occur during an earthquake and also at the post-quake stage until the failed soil masses come to a new static equilibrium. Upslope retrogression and downslope runout of the failed soil blocks are examined for varying geometries and soil properties. The present FE simulations can explain some of the conditions required for causing different types of seismic slope failure (e.g., spread, flowslide or monolithic slides) as observed in the field.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Modeling of large deformation behaviour of marine sensitive clays and its application to submarine slope stability analysis
No full textPost-slide investigations suggest that many large scale submarine landslides occur through marine sensitive clay layers. A nonlinear mathematical model for post-peak degradation of undrained shear strength of sensitive clay is proposed based on experimental results. A method for estimation of model parameters is presented. Incorporating the model, an analytical solution is developed to examine possible mechanisms of large scale submarine landslides. Analyses are performed for mild infinite slopes where the failure initiates from a “fully weakened zone” of soil having undrained shear strength lower than the shear stress acting parallel to the slope. The driving force, in excess of resistance, generated from the fully weakened zone is then transferred to the surrounding soil elements resulting in shear band formation due to strain-softening behaviour of sensitive clays. When the length of the fully weakened zone is greater than a critical length, catastrophic shear band propagation (self-driven without any additional external force) occurs that could result in large-scale offshore landslides. A simple design chart is developed to calculate the critical length. Compared with a previous study based on a linear post-peak shear strength degradation model (Puzrin and Germanovich 2005), the present study gives a conservative estimation of critical length for catastrophic shear band propagation.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
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