Fragile Points Research Articles

Sensitivity of seismic fragility curves to multiple parameters using CyberShake simulated ground motions

AbstractSeveral alternatives exist to compute seismic fragility curves. This study takes advantage of the large pool of site‐specific CyberShake simulated ground motions (GMs) to investigate the sensitivity of fragility curves to multiple analysis parameters: the analysis method (Multiple Stripe Analysis (MSA), Cloud Analysis (CA), or Incremental Dynamic Analysis), the number and intensity measure distribution of the GMs used, the GM selection method, and the amount of scaling. To this end, the fragility curve of a two‐dimensional steel frame is calculated for every analysis variation at the life safety limit state. By varying one parameter at a time, we can separate the effects of the various parameters from one another. We also assess the effect of the analysis parameters on the mean annual rate of exceedance of life safety. We find that if GMs are selected adequately for each method, different analysis methods can lead to consistent mean annual rates of exceedance despite some differences in their fragility curves. Generally, MSA and the proposed CA that models the increase of response variability with ground motion intensity best match empirical fragility points. The number of GMs affects the results for all analysis methods, while the intensity distribution of GMs affects results differently in different methods. When GMs are required to match earthquake scenario parameters in addition to intensity, more conservative fragility curves are obtained. Finally, fragility curves are sensitive to excessive scaling. This study provides important insights for performance‐based earthquake engineering.

Fragility analysis of existing RCC frame structure

This In recent years, number of studies have been carried out for the evaluation of vulnerability of structure during seismic events. Fragility analysis is one of the important probabilistic approach to estimate the damage data at different damage state during seismic events. The G+7 Reinforced Concrete frame structure is considered for analysis. The structure is analyzed in ETABS by Non-linear Pushover Analysis. Fragility curve developed for Non-linear Pushover Analysis from results obtained by capacity spectrum method for different damage states. The fragility curves are derived from analytical method. The fragility points for different damage states are derived from analytical formula. Fragility curve is plotted for probability in Y-axis and spectral displacement in X-axis for 4 different damage states from Non-linear Pushover Analysis. From Incremental Dynamic Analysis fragility curve plotted for probability in Y-axis and peak ground acceleration in X-axis for five different damage state. The behavior of fragility curve after achieving the 100% probability for different damage state is constant.

Topography and morphology of the Eira barbara diaphragm

BackgroundThe diaphragm, the main muscle involved in respiration and one of those responsible for maintaining life, is still little explored in terms of its morphology in wild animals. There are few studies on the anatomy of Eira barbara, a carnivorous mustelid that is a victim of the urbanization process. In order to contribute to the conservation of the species, we described the topography and morphology of the diaphragm, which may be involved in injuries caused by the impacts of human activities.ResultsWe studied five specimens of Eira barbara, whose diaphragmatic muscle had a dorsal insertion on the 14th thoracic vertebra, laterally between the 8th and 13th intercostal space (EIC) and ventrally on the 8th EIC, with attachment to the xiphoid process. Consisting of three muscle regions (lumbar, costal and sternal), the diaphragm in Eira barbara showed radially arranged bundles, with the right costal muscle being slimmer than the left; the left pillar wider than the right and between them were the aortic and esophageal hiatuses. The Y-shaped tendinous center housed the foramen of the vena cava bordering the right costal region. In the most dorsal portion of the diaphragm, between the costal regions and the diaphragmatic pillar, we found two triangular-shaped regions devoid of muscle.ConclusionsOur findings, when compared with the current literature, indicate that the location and positioning of the diaphragm are independent of the physical conformation of the species, and that the right costal region, as well as the triangular areas devoid of musculature, may be fragile points for herniation in cases of Eira barbara being run over.

Fragile points method for Euler–Bernoulli beams

In this paper, the recently introduced Fragile Points Method (FPM) is extended to study the static bending, free vibration, and mechanical buckling of isotropic and homogeneous case as well as functionally graded Euler–Bernoulli beams. The beam kinematics is based on the Euler–Bernoulli theory that assumes plane sections remain plane and perpendicular to the neutral axis of the deformed beam. The salient feature of the FPM is that it is a truly meshless method that employs simple local point-based polynomial test and trial functions. The key distinction is that the polynomial test and trial functions are discontinuous and constructed using radial basis functions, in contrast to the conventional Galerkin framework. Further, as the trial and test functions are discontinuous, the continuity requirement imposed by the continuous Galerkin framework is circumvented. The discontinuous trial and test functions lead to inconsistency; to alleviate this, we employ numerical flux corrections inspired by the discontinuous Galerkin method. The efficiency and robustness of the approach are tested with a few standard benchmark examples.

A fragile points method with a numerical-flux-based interface debonding model to simulate the delamination migration in composite laminates

Predicting damage in composite laminates is essential for a better utilization of the material, but it is challenging especially when the inter- and intra-ply damages are coupled. In this paper, a Fragile Points Method (FPM) with a numerical-flux-based interface debonding model is proposed to simulate the laminates’ damage. The FPM is a novel meshless method using the discontinuous Galerkin weak formulations and the point-based discontinuous polynomial trial functions. In this work, an orthotropic interface debonding model has been developed based on the numerical fluxes to simulate the mixed-mode inter- and intra-ply damage. For any interior interface in an FPM model, the interface damage is triggered when the damage criterion is satisfied and the interface is separated when the fracture energy is reached. Due to the discontinuous characteristics of the FPM, the inter- and intra-ply damage modes are introduced explicitly, and thus the coupling between them can be naturally captured. In this paper, the proposed FPM is verified by four benchmark examples for Mode I, Mode II and Mixed Mode delamination. Then the proposed method is applied to simulate the delamination migration, used as an example for the inter- and intra-ply damage. The FPM results show that this method is able to provide reliable prediction on the load–displacement curves as well as the damage and crack patterns, and the mechanism governing the delamination migration is also discussed based on the FPM results.

Physical and mechanical properties of hard seed coat on the example of Gleditsia triacanthos L.

The microhardness of individual morphological structures of the hard coat of the seed of Gleditsia triacanthos L. was measured. Measurements were made on the transverse and frontal planes. Based on the differences in the hardness of the two planes, the anisotropy of the seed coat was revealed. The entire seed coat has a special hardness which can be compared with the hardness of hardwood like oat wood. An interesting feature was the hardness of the endosperm, comparable to the hardness of the epidermis. Further study of the processes that occur in seeds during imbibition is based on the obtained data. Mathematical modeling methods are the most promising for these tasks; they will help to identify the points of fragility and the points of the greatest tension in the seed coat. These results will allow us to find the best ways to destroy the seed coat and to accelerate the germination. Research of physical properties of the seed coat is of practical importance in the fact that in the future it will allow reducing of the hard-seeding and increasing the germination of seeds. The obtained data allows us to represent the initial hardness of the seed coat.

Investigating solid-waste management in the Cariri Oeste Region using the Updated Waste Management Condition Index – ICGRA

The northeast region of Brazil has poor waste management and lags in compliance with the National Solid-Waste Policy. The use of indicators is a promising alternative for the specific assessment of solid-waste management conditions. This study investigated the solid-waste management system of municipalities in the Cariri Oeste region (CE) through the characterization of management services and application of the Updated Waste Management Condition Index (ICGRA) method. In ICGRA, indicators are grouped into four categories, namely the characteristics of the management system, Management System Planning, Operational Conditions of the Management System, and specific indicators of the PNRS and new technologies. Data and information regarding the indicators were obtained from websites, academic literature, plans and studies relevant to the subject, field visits, contact with municipal managers, and photographic records. After applying the data diagnosed in the ICGRA method, an inadequate management scenario was determined for all the evaluated municipalities. This result, linked to field observations, complemented the diagnosis, which reflected the status of municipalities. The most fragile points observed in the ICGRA results concern the management compliance with the provisions of PNRS and new technologies. ICGRA proved to be effective in evaluating the management of municipal solid waste in the CE region.

“Decolonising” museums through experimental practices: the case of MUBIG, a neighbourhood museum in Milan

The article is focused on MUBIG, an experimental museum in a peripheral neigbourhood of Milan. The museum, a fluid, scattered, dynamic discourse – a process, more than a place – is born out of an urban regeneration project. The reflection attempts to articulate a number of key questions: how are the individual histories embodied by the museum? What points of fragility are envisaged in this regard and how are they addressed, in order to prevent tokenism and the rhetoric of participation perse? What is the role of the visual dimention and of contemporary art? Throughout the article, I argue that neighbourhood museums might be one of the many actors needed on the scene of decolonisation, by this term meaning a process of space-making around the commons based on representation and radical listening. The experience is analyses here through a double lens: while being a member of the collective who co-designed it, I also look at it from my academic position. This allows me to describe the process keeping different “points of distance,” therefore layering methodologies and viewpoints.

Participatory diagnosis of food systems fragility; perspectives from Thailand

Much of the effort toward building resilience has been directed at identifying appropriate metrics and indicators of system resilience, and from this, interventions to strengthen resilience. An essential ingredient of such resilience-building efforts is to apply public processes of dialogue and diagnosis to identify systems fragility and potential for failure. Social learning processes allow people to take new perspectives in understanding their own and other's interests and values, to identify problems and formulate solutions by focusing on the potential for systemic failure. Diagnosis and dialogue tools used in a participatory process in Northern Thailand included food systems mapping, identifying potential points of failure within systems, and applying a self-assessment tool structured around resilience characteristics. This process proved important for developing stakeholder understanding of systems thinking and of concepts of resilience. Yet it is a process that is not without challenges. We noted the difficulty with defining food system boundaries and the tendency for participants to persist with familiar understandings of problems within their sector, with it taking time to shift to thinking about points of fragility within the whole system. We particularly recognize the participatory process itself as being of value, in addition to the specific outcomes such as risk identification or interventions for resilience.

Mechanistic Insights on Hyperthermic Intraperitoneal Chemotherapy in Ovarian Cancer.

Epithelial ovarian cancer is an aggressive disease of the female reproductive system and a leading cause of cancer death in women. Standard of care includes surgery and platinum-based chemotherapy, yet patients continue to experience a high rate of recurrence and metastasis. Hyperthermic intraperitoneal chemotherapy (HIPEC) treatment in highly selective patients extends overall survival by nearly 12 months. The clinical studies are highly supportive of the use of HIPEC in the treatment of ovarian cancer, though the therapeutic approach is limited to academic medical centers. The mechanism underlying HIPEC benefit remains unknown. The efficacy of HIPEC therapy is impacted by several procedural and patient/tumor factors including the timing of surgery, platinum sensitivity, and molecular profiling such as homologous recombination deficiency. The present review aims to provide insight into the mechanistic benefit of HIPEC treatment with a focus on how hyperthermia activates the immune response, induces DNA damage, impairs DNA damage repair pathways, and has a synergistic effect with chemotherapy, with the ultimate outcome of increasing chemosensitivity. Identifying the points of fragility unmasked by HIPEC may provide the key pathways that could be the basis of new therapeutic strategies for ovarian cancer patients.

Integrating Family Farming into School Feeding: A Systematic Review of Challenges and Potential Solutions

Family farming is strengthening its strategic role in school nutrition, but coordinating between school feeding programs and the agricultural sector has proven to be challenging. The goal of this review was to identify the problems that school feeding programs face in acquiring food from family farms. We selected studies from Web of Science, Medline/PubMed, and Scopus and evaluated their methodological quality. Out of 338 studies identified, 37 were considered relevant. We used PRISMA to guide the review process, and we chose not to limit the year or design of the study because it was important to include the largest amount of existing evidence on the topic. We summarized the main conclusions in six categories: local food production, marketing, and logistics channels, legislation, financial costs, communication and coordination, and quality of school menus. In general, the most critical problems emerge from the most fragile point, which is family farming, particularly in the production and support of food, and are influenced by the network of actors, markets, and governments involved. The main problems stem from the lack of investment in family farming and inefficient logistics, which can negatively impact the quality of school meals. Viable solutions include strategies that promote investment in agricultural policies and the organization of family farmers.

Study of the Fragile Points Method for solving two-dimensional linear and nonlinear wave equations on complex and cracked domains

This paper presents the meshless Fragile Points Method (FPM) for the two-dimensional linear and nonlinear wave equations on irregular and complex domains. Time derivatives of the wave equation are discretized using finite difference schemes, and the theorems of stability and convergence of this semi-discrete scheme are given. A simple Galerkin was applied with the domain divided into subdomains by a Voronoi diagram for spatial discretization of problems. Numerical flux corrections are applied to avoid incompatibilities in this study. In case of encountering a crack or discontinuity in the common neighborhood of the selected points, the connection between the two points is cut off without making any particular change in the result. Hence in this method, the points are called “fragile” and it is suitable for solving problems with cracks and discontinuities. A predictor–corrector scheme is used to obtain an appropriate approximation for the nonlinear term in the wave equation. FPM yields symmetric and sparse point stiffness matrices, making it a computationally efficient method that reaches the appropriate accuracy in a short time according to the conditions of the problem. Test problems on complex and cracked domains are evaluated that show the acceptable accuracy and efficiency of the proposed method.

A meshless fragile points method for the solution of the monodomain model for cardiac electrophysiology simulation

Meshless methods for in silico modeling and simulation of cardiac electrophysiology are gaining more and more popularity. These methods do not require a mesh and are more suitable than the Finite Element Method (FEM) to simulate the activity of complex geometrical structures like the human heart. However, challenges such as numerical integration accuracy and time efficiency remain, which limit their applicability. Recently, the Fragile Points Method (FPM) has been introduced in the meshless methods family. It uses local, simple, polynomial, discontinuous functions to construct trial and test functions in the Galerkin weak form. This allows for accurate integration and improved efficiency while enabling the imposition of essential and natural boundary conditions as in FEM. In this work, we consider the application of FPM for cardiac electrophysiology simulation. We derive the cardiac monodomain model using the FPM formulation and we solve several benchmark problems in 2D and 3D. We show that FPM leads to solutions of accuracy and efficiency similar to FEM while alleviating the need for a mesh. Additionally, FPM demonstrates comparable convergence to FEM in the considered benchmarks.

Financial structure, cycle, and instability

The subprime loan mortgage crisis has revived scholarly interest in Minsky’s financial instability hypothesis. The related mathematical models present two types of Minskian financial structures. We construct macrodynamic models that consider both structures and discuss financial instability and cycles. We also demonstrate that one of the financial cycles occurs when a real factor stabilizes the economy. The burden of interest-bearing debt is an important determinant of the cycle. We posit that the escalating financial fragility in this cycle is a more appropriate interpretation of the Minskian financial structure that refers to hedging, speculative and Ponzi behaviors. We further demonstrate that another financial structure destabilizes the economy. If the instability occurs at the point of fragility, then the economy may deteriorate into financial crisis. Fragility then becomes instability.

A meshless fragile points method for rule-based definition of myocardial fiber orientation

Background and objective: Rule-based methods are commonly used to estimate the arrangement of myocardial fibers by solving the Laplace problem with appropriate Dirichlet boundary conditions. Existing algorithms are using the Finite Element Method (FEM) to solve the Laplace–Dirichlet problem. However, meshless methods are under development for cardiac electrophysiology simulation. The objective of this work is to propose a meshless rule based method for the determination of myocardial fiber arrangement without requiring a mesh discretization as it is required by FEM.Methods: The proposed method employs the Fragile Points Method (FPM) for the solution of the Laplace–Dirichlet problem. FPM uses simple discontinuous trial functions and single-point exact integration for linear trial functions that set it as a promising alternative to the Finite Element Method. We derive the FPM formulation of the Laplace–Dirichlet and we estimate ventricular and atrial fiber arrangements according to rules based on histology findings for four different geometries. The obtained fiber arrangements from FPM are compared with the ones obtained from FEM by calculating the angle between the fiber vector fields of the two methods for three different directions (i.e., longitudinal, sheet, transverse).Results:The fiber arrangements that were generated with FPM were in close agreement with the generated arrangements from FEM for all three directions. The mean angle difference between the FPM and FEM vector fields were lower than 0.030∘ for the ventricular fiber arrangements and lower than 0.036∘ for the atrial fiber arrangements.Discussion:The proposed meshless rule-based method was proven to generate myocardial fiber arrangements with very close agreement with FEM while alleviates the requirement for a mesh of the latter. This is of great value for cardiac electrophysiology solvers that are based on meshless methods since they require a well defined myocardial fiber arrangement to simulate accurately the propagation of electrical signals in the heart. Combining a meshless solution for both the determination of the fibers and the electrical signal propagation can allow for solution that do not require the definition of a mesh. To our knowledge, this work is the first one to propose a meshless rule-based method for myocardial fiber arrangement determination.

MACROECONOMIC STRATEGIC PLAN AS AN ALTERNATIVE TOOL FOR REDESIGNING OF PREFERENCES AND PRIOTIES OF THE NATIONAL ECONOMY: PROPOSAL FOR EMERGING MARKETS ECONOMY

Amaç: Kamu otoriteleri, gelecekteki operasyonlarında yeni fırsatları gözetebilmek ve sistemdeki aktörler arasında eşgüdümlü aksiyonlar alarak geleceğe dair öngörülerinin tutarlığını arttırabilmek maksadıyla sürdürülebilirliği ve kapsayıcılığı yüksek makro ölçekli stratejik planların tasarımını önemsemektedirler. Bu çalışmada kilit makroekonomik performans ve istikrar göstergeleri analiz edilmiş, karar alma ve uygulama süreçlerinin aktörler açısından kesiştiği/ayrıştığı alanlar ile ulusal ekonominin tercihleri ve öncelikleri değerlendirilerek yükselen piyasalar için alternatif bir makroekonomik stratejik plan tasarlamak amaçlanmıştır.
 Yöntem: Çalışmada ilk olarak seçilmiş yükselen piyasa ekonomilerine ilişkin makroekonomik göstergeler ve iç/dış paydaşlar tarafından hazırlanan raporlar incelenerek ülkelerin mevcut durumları belirlenmiştir. Daha sonra SWOT ve PEST yaklaşımları kullanılarak 21. yüzyılda yaşanan gelişmelerin etkisiyle oluşturulmasının gerekliliği ortaya çıkan makroekonomik stratejik plana uygun olacak şekilde yeni bir matris tasarımı yapılmıştır. Ardından oluşturulan yeni matriste yer alan faktör elemanlarının önem derecelerini belirlemek amacıyla Analitik Hiyerarşi Süreci (AHP) kullanılmıştır. AHP yöntemi ile makroekonomik stratejik planın ana eksenleri ve bileşenleri için ikili karşılaştırma matrisleriyle ağırlıklar elde edilmiştir. Böylece ülkelerin hangi makroekonomik ana eksene ve üretilen strateji önerisine daha fazla önem vermeleri gerektiği ortaya çıkarılmıştır.
 Bulgular: Çalışma sonucunda yükselen piyasa ekonomilerinin tercih ve önceliklerini güncelleme sürecinde en önemli ana ekseni, mukayeseli dezavantaj oluşturabilecek alanlar olduğu belirlenmiştir. İlgili ülkelerin ekonomik ilerlemelerinin olası engeli olarak görülebilecek dezavantaj noktalarının belirlenmesi ve uygun tedbirleri üretmesi gerekmektedir. Ayrıca, birinci strateji yükselen piyasa ekonomileri için kamu otoritesi tarafından oluşturulacak stratejik plan açısından ulusal ekonomik güvenlik ve savunma sisteminin, ulusal yapının ve ilişkiler sisteminin güçlendirilmesine öncelik verilmesi gerektiği sonucuna ulaşılmıştır. İkinci en önemli strateji ise, iş dünyasının yükümlülüğü olarak ele alınan işletmelerin stratejik tepki üretme kapasitesinin iyileştirilmesidir.
 Özgünlük: Çalışmada, 21. yüzyılın gereklilikleri ve ülkelerin girdiği yeni patikalar dikkate alınarak yükselen piyasalar için özgün bir makroekonomik stratejik planın bileşenleri SWOT ve PEST yaklaşımları bağlamında ele alınmıştır. Bu sebeple, çalışma literatüre yeni bir makroekonomik stratejik plan önerisi geliştirme bakımından katkı sağlamaktadır. Çalışmada elde edilen stratejik planın bileşenlerinin önem derecelerinin belirlenmesiyle oluşturulan plan, politika yapıcılar için izlenecek bir yol haritası niteliği taşımaktadır. Ayrıca çalışmada disiplinler arası bir yaklaşım sergilenerek ekonomi politik bir analiz ortaya konmuştur.

Epigenetics and Congenital Heart Diseases.

Congenital heart disease (CHD) is a frequent occurrence, with a prevalence rate of almost 1% in the general population. However, the pathophysiology of the anomalous heart development is still unclear in most patients screened. A definitive genetic origin, be it single-point mutation or larger chromosomal disruptions, only explains about 35% of identified cases. The precisely choreographed embryology of the heart relies on timed activation of developmental molecular cascades, spatially and temporally regulated through epigenetic regulation: chromatin conformation, DNA priming through methylation patterns, and spatial accessibility to transcription factors. This multi-level regulatory network is eminently susceptible to outside disruption, resulting in faulty cardiac development. Similarly, the heart is unique in its dynamic development: growth is intrinsically related to mechanical stimulation, and disruption of the intrauterine environment will have a direct impact on fetal embryology. These two converging axes offer new areas of research to characterize the cardiac epigenetic regulation and identify points of fragility in order to counteract its teratogenic consequences.

Knapsack Cipher-based metaheuristic optimization algorithms for cryptanalysis in blockchain-enabled internet of things systems

The integration of the Internet of Things (IoT) and blockchain demand the use of public-key cryptography systems to secure network communications. In this study, one of those public-key algorithms, known as Merkle–Hellman Knapsack Cryptosystem (MHKC), is employed to cryptographically analyze its utilization for blockchain technology using a metaheuristic algorithm. To do so, eight well-known metaheuristic algorithms are employed to determine the trustworthiness of MHKC against cryptoanalysis attacks using various knapsack lengths, ranging from 8 to 32 bits. The experimental findings showed that pathfinder algorithm (PFA) and slime mold optimizer (SMA) could exploit MHKC under 8-bit ASCII code, and their performance gradually deteriorates with higher bit representations, while the performance of manta ray foraging optimization (MRFO) could be superior for the knapsack lengths higher than 8-bit. Additionally, MRFO would not attack MHKC under 32-bit; thus, some genetic operators have been integrated to manipulate the binary solutions obtained by this algorithm to promote its exploration capability in a variant, namely HMRFO. The experimental findings revealed that HMRFO is a better alternative to the existing ones for attacking the MHKC with knapsack lengths higher than 8-bit to appear their fragility points, while both SMA and PFA are competitive for 8-bit ASCII code and superior to the other algorithms.

Ideal Glass Transitions from the View Point of Fragility in Polymer-Dimer Mixture

Ideal Glass Transitions from the View Point of Fragility in Polymer-Dimer Mixture

A new meshless Fragile Points Method (FPM) with minimum unknowns at each point, for flexoelectric analysis under two theories with crack propagation, I: Theory and implementation

Flexoelectricity refers to a phenomenon which involves a coupling of the mechanical strain gradient and electric polarization. In this study, a meshless Fragile Points Method (FPM), is presented for analyzing flexoelectric effects in dielectric solids. Local, simple, polynomial and discontinuous trial and test functions are generated with the help of a local meshless Differential Quadrature approximation of derivatives. Both primal and mixed FPM are developed, based on two alternate flexoelectric theories, with or without the electric gradient effect and Maxwell stress. In the present primal as well as mixed FPM, only the displacements and electric potential are retained as explicit unknown variables at each internal Fragile Point in the final algebraic equations. Thus the number of unknowns in the final system of algebraic equations is kept to be absolutely minimal. An algorithm for simulating crack initiation and propagation using the present FPM is presented, with classic stress-based criterion as well as a Bonding-Energy-Rate(BER)-based criterion for crack development. The present primal and mixed FPM approaches represent clear advantages as compared to the current methods for computational flexoelectric analyses, using primal as well as mixed Finite Element Methods, Element Free Galerkin (EFG) Methods, Meshless Local Petrov Galerkin (MLPG) Methods, and Isogeometric Analysis (IGA) Methods, because of the following new features: they are simpler Galerkin meshless methods using polynomial trial and test functions; minimal DoFs per Point make it very user-friendly; arbitrary polygonal subdomains make it flexible for modeling complex geometries; the numerical integration of the primal as well as mixed FPM weak forms is trivially simple; and FPM can be easily employed in crack development simulations without remeshing or trial function enhancement.