Web Configurations Research Articles

Structural topology optimization for plastic-limit behavior of I-beams, considering various beam-column connections

This work proposes topology optimization for steel I-beams, including consideration of bolted beam-column connections with geometric and material nonlinear analysis. The aim is to assess and compare the topological configurations influenced by different connections, examining their stress distribution and rotational stiffness to illustrate the potential of structural optimization. The bi-directional evolutionary structural optimization (BESO) approach is implemented. Furthermore, several bolted steel beam-column configurations were validated based on experimental tests. Subsequently, a series of finite element models were developed, contributing to a comprehensive understanding of the plastic-limit behavior of I-beams under different loading conditions. The proposed method could potentially use a lesser quantity of material while maintaining the same level of structural performance. The results indicate that the implementation of structural topology optimization on I-beams while considering various beam-column connections, yields structural performance similar to that of solid web configurations, achieved through material reduction.

Structural evaluation of I-joists with corrugated panel web

Joists with corrugated panel webs are a structural solution that has been little tested on wood-based materials. This study has the objective to develop the potential of wooden I-joists with two different web configurations. Joists with corrugated webs were manufactured and tested in bending tests to determine their mechanical properties. The shear capacity of a joist with a single-panel corrugated web is only 45 %, while a joist with a double-panel corrugated web offers 87 % compared with commercial I-joists. The failure mode of joists is initiated by buckling, followed by the creation of diagonal tension lines in the corrugated web.

Fibre Blend and Web Arrangement for Optimized Dust-Holding, Hydrophobic, and Thermal Properties of Needle-Punched Nonwovens

PM2.5 filters with hydrophobicity and thermal resistance are preferable for automobile cabins, engine air intake, and indoor applications, safeguarding against moisture ingress, microbial growth, and temperature fluctuations, and ensuring optimal air quality. This study explored the effects of blending five fibres with different web arrangements and fibre blend compositions on needle-punched dust-holding, hydrophobic, and thermal properties. Polyphenylene sulfide (PPS), polypropylene (PP), polyester (PET), polylactic acid (PLA), and polyacrylonitrile (PAN) were blended in different proportions to produce the samples. The method included opening, blending, carding, web laying, and needle punching to produce eight samples with cross-laid, parallel-laid, and pre-needled parallel-laid web configurations. Standard test methods were employed for the characterization. The results showed a dust holding capacity of > 3,423,000 particles/cm2, the highest WCA of 133.12°, and the highest thermal resistance of 0.24255 m2KW−1. Based on the ANOVA analysis, web arrangement and pre-needling did not have a significant impact on the hydrophobicity of the samples. N0, N1, and N2 showed similar high water contact angles (~ 126°), indicating that the hydrophobicity was more affected by the chemistry of the fibre blend than by the web structure. Turkey’s analysis of other samples strengthened this idea. However, they had a substantial impact on the porosity, air permeability, dust-holding capacity, and thermal properties at a P-value ≤ 0.05. The findings provide insightful information regarding the complex interactions among fibre content, web layout, and pre-needling to develop sophisticated needle-punched PM2.5 filters.

DE-type little strings from glued brane webs

We propose brane web configurations for D-type and E-type mathcal{N} =(1,0) little string theories based on a trivalent or quadrivalent gluing of 5-brane web diagrams. Tri-/quadri-valent gluing is a powerful way of computing 5d/6d partition functions for supersymmetric gauge theories based on the topological vertex. We generalize the gluing techniques to little string theories by introducing a new compact direction and compute their supersymmetric partition functions on Omega-deformed ℝ4×T2. As concrete examples, we consider little string theories arising from Type IIB NS5-branes probing D4 or D5 singularity. Their effective gauge theory descriptions as the affine D4 or D5 quiver gauge theory can be realized with quadrivalent or trivalent gluing, respectively. Based on these gluings of 5-brane webs, we compute their refined partition functions and compare them with the known results. We extend the computation of the partition function to little string theory engineered from IIB NS5-branes probing E6 singularity based on a trivalent gluing. We also discuss the generalization to higher rank cases and the symmetries of the partition functions.

Filling the gap: a series of 3D-printed titanium truss cages for the management of large, lower limb bone defects in a developing country setting.

Large segmental long bone defects are notoriously difficult to manage. Treatment is resource-intensive due to the complexity, cost, and specialized skills required. Truss designs are known for their triangular shapes organized in web configurations. This allows for maximal mechanical strength, the least mass, and a lattice that can be filled with bone graft. Using a truss cage combined with contemporary internal fixation provides immediate stability for bone ingrowth and long-term potential union. The implant is designed using virtual 3D modelling of the patient's bone defect based on a CT scan. The truss cage can be used in a staged procedure combined with Masquelet's induced membrane technique. This study aims to review the outcomes of patient-specific, locally designed 3D titanium truss cages packed with cancellous autograft in treating segmental, long bone defects in the lower limb in a developing country setting. This retrospective series reviewed cases performed at various institutions between January 2019 and March 2022. Parameters assessed included patient demographics, size and location of the defect, time to clinical and radiological union and complications. Nine cases were included for review, with a mean age of 36years (range 19-52). Defects ranged from 60 to 205mm, and eight cases were staged procedures. Eight cases used intramedullary reamings as bone graft. Contemporary intramedullary nails were used for fixation in all cases. No peri- or post-operative complications occurred. All cases progressed to functional union. 3D-printed titanium truss cages combined with bone graft appear to be an effective treatment of large bone defects in the lower limb in a developing country setting in the short term. No complications were encountered, but longer follow-up is needed before definitive recommendations can be made. Level IV (retrospective case series).

Water Ecosystems Tool (WET) 1.0 – a new generation of flexible aquatic ecosystem model

Abstract. We present the Water Ecosystems Tool (WET) – a new generation of open-source, highly customizable aquatic ecosystem model. WET is a completely modularized aquatic ecosystem model developed in the syntax of the Framework for Aquatic Biogeochemical Models (FABM), which enables coupling to multiple physical models ranging from zero to three dimensions, and is based on the FABM–PCLake model. The WET model has been extensively modularized, empowering users with flexibility of food web configurations, and incorporates model features from other state-of-the-art models, with new options for nitrogen fixation and vertical migration. With the new structure, features and flexible customization options, WET is suitable in a wide range of aquatic ecosystem applications. We demonstrate these new features and their impacts on model behavior for a temperate lake for which a model calibration of the FABM–PCLake model was previously published and discuss the benefits of the new model.

PENGGABUNGAN DUA KONEKSI INTERNET SERVICE PROVIDER DENGAN TEKNIK LOAD BALANCING MENGGUNAKAN METODE EQUAL COST MULTI PATH (ECMP)

Computer networks are considered a primary need in the globalization era. Computer networks often used simultaneously at some specific times, leading to a bandwidth overload on the computer network. Overloaded bandwidth can cause disturbances, such as a slower network connection. This study discusses a merge of two internet service providers connections by applying a load balancing technique, namely the equal-cost multipath method. Several stages carried out in this study, including analysis, design, simulation or prototyping, implementation, monitoring, and management. This study successfully shows that an increase in the QoS value can be seen from the test parameters performed. The average throughput and jitter on all computers have increased by 0.17% and 0.68 milliseconds. The average delay for all computers has decreased by 0.9 milliseconds, whereas the average packet loss in all computers experienced a 0.58% quality improvement. Web configurations have been conducted to make the study more manageable.

Beyond sticks and stones: Integrating physical and ecological conditions into watershed restoration assessments using a food web modeling approach

Watershed assessments have become common for prioritizing restoration in river networks. These assessments primarily focus on geomorphic conditions of rivers but less frequently incorporate non-geomorphic abiotic factors such as water chemistry and temperature, and biotic factors such as the structure of food webs. Using a dynamic food web model that integrates physical and ecological environmental conditions of rivers, we simulated how juvenile salmon (Oncorhynchus spp.) biomass responded to restoration at twelve sites distributed across the Methow River (Washington, USA), ranging from headwater tributaries to mainstem reaches. We explored responses to three common river restoration strategies: (1) physical habitat modification, (2) nutrient supplementation, and (3) increased riparian vegetation cover. We also simulated how different food web configurations that exist in salmon-bearing streams, such as the presence of ‘non-target’ fishes and ‘armored’ predation resistant invertebrates, could mediate restoration outcomes. Some locations in the river network experienced relatively large increases in modeled fish biomass with restoration, whereas other locations were almost entirely unresponsive. Spatial variation in restoration outcomes was primarily controlled by non-geomorphic environmental conditions, such as nutrient availability, water temperature, and stream canopy cover. Restoration responses also varied significantly with different food web configurations, suggesting that as the structure of food webs varies across river networks, so too could the outcome of restoration. These findings illustrate that ecological responses to restoration may exhibit substantial spatial variation within river networks, resulting from heterogeneity in environmental conditions that are commonly overlooked—but which can and should be considered—in restoration planning and prioritization.

Seasonal variability of the fatty acid composition in Aurelia aurita (Cnidaria: Scyphozoa): implications for gelativore food web studies.

Jellyfish population play an important role in aquatic food chains, and many animals predate on this ‘mostly water containing’ organisms. However, what gelativores predators could gain from their prey is still poorly understood. This study provides insight into the nutritional value of the moon jelly (Aurelia aurita) by means of its fatty acid (FA) composition, while investigating seasonal variability and differences between its free-swimming life stages. A biweekly sampling was carried out in a temperate coastal ecosystem, the Kiel Fjord, Germany and during two consecutive years. FA profile of A. aurita showed significant seasonal variability, while mature medusae (due to reproductive tissues) possessed highest FA content. In addition, moon jelly contained several essential FAs (i.e. arachidonic acid, 20:4ω6; eicosapentaenoic acid, 20:5ω3; docosahexaenoic acid, 22:6ω3), which likely support predator’s vital physiological functions. Even though total FA contents proved to be low (7 × 10−3–34 × 10−3% per g dry weight), evidence supporting A. aurita’s capability to meet the dietary requirements of predators such as fish and crustaceans is provided. Finally, implications for gelativore and future food web configurations are discussed, while proposing that jellyfish are likely to be, and become, more than an opportunistic prey to many organisms.

5-brane webs for 5d mathcal{N} = 1 G2 gauge theories

We propose 5-brane webs for 5d mathcal{N} = 1 G2 gauge theories. From a Higgsing of the SO(7) gauge theory with a hypermultiplet in the spinor representation, we construct two types of 5-brane web configurations for the pure G2 gauge theory using an O5-plane or an tilde{mathrm{O}5} -plane. Adding flavors to the 5-brane web for the pure G2 gauge theory is also discussed. Based on the obtained 5-brane webs, we compute the partition functions for the 5d G2 gauge theories using the recently suggested topological vertex formulation with an O5-plane, and we find agreement with known results.

Five-brane webs and highest weight representations

We consider BPS-counting functions mathcal{Z} N,M of N parallel M5-branes probing a transverse ℤM orbifold geometry. These brane web configurations can be dualised into a class of toric non-compact Calabi-Yau threefolds which have the structure of an elliptic fibration over (affine) AN −1. We make this symmetry of mathcal{Z} N,M manifest in particular regions of the parameter space of the setup: we argue that for specific choices of the deformation parameters, the supercharges of the system acquire particular holonomy charges which lead to infinitely many cancellations among states contributing to the partition function. The resulting (simplified) mathcal{Z} N,M can be written as a sum over weights forming a single irreducible representation of the Lie algebra mathfrak{a} N −1 (or its affine counterpart). We show this behaviour explicitly for an extensive list of examples for specific values of (N, M ) and generalise the arising pattern for generic configurations. Finally, for a particular compact M5-brane setup we use this form of the partition function to make the duality N ↔ M manifest.

Seismic behaviour of steel plate shear wall systems with staggered web configurations

SummaryUnstiffened steel plate shear walls (SPSWs) are used as lateral load‐resisting systems in building structures. The energy dissipation mechanism of SPSWs consists of the tension yielding of web plates and the formation of plastic hinges at the ends of horizontal boundary elements. However, vertical boundary elements (VBEs) of high‐rise SPSWs may experience high axial forces under lateral loading. This study explores the effectiveness of staggering of web plates on the reduction of VBE forces and drift response of SPSWs during an earthquake event. An analytical study has been conducted to determine the base shear reduction factor so as to match the overstrength of staggered systems with conventional SPSWs. A design methodology has been proposed for staggered SPSWs. Six‐, 9‐, and 20‐storey staggered and conventional SPSWs with varying aspect ratios are considered in this study to compare their seismic response. These study frames are modelled and analysed in OpenSEES platform. Nonlinear static and dynamic analyses are performed to compare the drift response, hinge mechanisms, and steel tonnage. Staggered SPSWs showed uniform drift distribution and reduction in interstorey drift and axial force demand on the VBEs.

Experimental investigation and analysis on flexural behavior of CFSTTC beams

A series of experiments and analyses on the flexural behavior of concrete filled steel tubular truss composite (CFSTTC) beams were presented in this paper. Flexural tests were performed with two CFSTTC beams with different web configurations: one specimen has the transverse and diagonal braces and the other one only has transverse braces. The failure modes, deflection shapes, load capacities, strain responses at different locations as well as the local buckling phenomenon on the two tested specimens were evaluated. Some suggestions were proposed to prevent the local buckling on CFSTTC structures. Finite element (FE) models were developed and verified by the obtained experimental results. In addition, parametric studies were conducted to investigate the influence of core concrete in chords, concrete slab etc. A simplified method was proposed in this paper to predict the flexural strength of CFSTTC beams with fully or partially concrete filled chords. The proposed method was validated on the basis of the experimental and numerical results.

Biomass Reallocation between Juveniles and Adults Mediates Food Web Stability by Distributing Energy Away from Strong Interactions.

Ecological theory has uncovered dynamical differences between food web modules (i.e. low species food web configurations) with only species-level links and food web modules that include within-species links (e.g. non-feeding links between mature and immature individuals) and has argued that these differences ought to cause food web theory that includes within-species links to contrast with classical food web theory. It is unclear, however, if life-history will affect the observed connection between interaction strength and stability in species-level theory. We show that when the predator in a species-level food chain is split into juvenile and adult stages using a simple nested approach, stage-structure can mute potentially strong interactions through the transfer of biomass within a species. Within-species biomass transfer distributes energy away from strong interactions promoting increased system stability consistent with classical food web theory.

Top-down consumptive and trait-mediated control do affect soil food webs: It’s time for a new model

Soil food webs are complex and exhibit many of the features that are indicative of bottom-up or resource control. The perceived dominance of bottom-up control has resulted in food web models that have underexplored mechanisms of top-down or predator control. Developing soil food web models that include more mechanisms of top-down control may improve our ability to predict changes in food web configurations and ecosystem processes. Specifically, models could be improved by considering more detailed density-mediated and trait-mediated top-down effects via the inclusion of non-linear feeding relationships and context-specific variation in physiology, morphology, and behavior.

A management oriented 1-D ecosystem model: Implementation in the Gulf of Trieste (Adriatic Sea)

In this paper a coupled physical–biogeochemical one-dimensional numerical model (BFM–POM 1D) was implemented in the Gulf of Trieste, (northern Adriatic Sea) and its structure was tested in order to evaluate its usability as a tool to support coastal management and planning. The evaluation concerned the ability of the model to reproduce the main trophic pathways, as well as their temporal variability, in terms of seasonal variations. The ecosystem structure comprised three phytoplankton groups, four zooplankton groups, one bacterial group, and a simple benthic return in order to parametrise benthic processes. The dynamics and interactions between groups were studied, as well as the model’s sensitivity to different trophic web configurations. Results showed that the model was capable of replicating the behaviour of seasonal vertical profiles of the major biogeochemical elements, and the prevalence of the microbial food web shaping the trophic chain in the Gulf of Trieste. The model also responded to strong forcings at the surface and different trophic arrangements, thus providing initial evidence of its potential as a scientific tool aimed at marine coastal management.

Trophic Transfer of Methyl Siloxanes in the Marine Food Web from Coastal Area of Northern China

Methyl siloxanes, which belong to organic silicon compounds and have linear and cyclic structures, are of particular concern because of their potential characteristic of persistent, bioaccumulated, toxic, and ecological harm. This study investigated the trophic transfer of four cyclic methyl siloxanes (octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), dodecamethylcyclohexasiloxane (D6), and tetradecamethylcycloheptasiloxane (D7)) in a marine food web from coastal area of Northern China. Trophic magnification of D4, D5, D6, and D7 were assessed as the slope of lipid equivalent concentrations regressed against trophic levels of marine food web configurations. A significant positive correlation (R = 0.44, p < 0.0001) was found between lipid normalized D5 concentrations and trophic levels in organisms, showing the trophic magnification potential of this chemical in the marine food web. The trophic magnification factor (TMF) of D5 was estimated to be 1.77 (95% confidence interval (CI): 1.41-2.24, 99.8% probability of the observing TMF > 1). Such a significant link, however, was not found for D4 (R = 0.14 and p = 0.16), D6 (R = 0.01 and p = 0.92), and D7 (R = -0.15 and p = 0.12); and the estimated values of TMFs (95% CI, probability of the observing TMF > 1) were 1.16 (0.94-1.44, 94.7%), 1.01 (0.84-1.22, 66.9%) and 0.85 (0.69-1.04, 48.6%) for D4, D6, and D7, respectively. The TMF value for the legacy contaminant BDE-99 was also estimated as a benchmark, and a significant positive correlation (R = 0.65, p < 0.0001) was found between lipid normalized concentrations and trophic levels in organisms. The TMF value of BDE-99 was 3.27 (95% CI: 2.49-4.30, 99.7% probability of the observing TMF > 1), showing the strong magnification in marine food webs. To the best of our knowledge, this is the first report on the trophic magnification of methyl siloxanes in China, which provided important information for trophic transformation of these compounds in marine food webs.

Concentrations and trophic magnification of cyclic siloxanes in aquatic biota from the Western Basin of Lake Erie, Canada

We examine the concentrations and food web biomagnification of three cyclic volatile methylsiloxanes (cVMS) octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) using aquatic biota collected from Lake Erie. Concentrations of cVMS in biota were within the range reported for other studies of cVMS in aquatic biota. Trophic magnification factors (TMF) were assessed in various food web configurations to investigate the effects of food web structure. TMF estimates were highly dependent on the inclusion/exclusion of the organisms occupying the highest and lowest trophic levels and were >1 for D4 and D5, indicating biomagnification, in only 1 of the 5 food web configurations investigated and were <1 in the remaining 4 food web configurations. TMF estimates for PCB180 were also dependant on food web configuration, but did not correspond with those obtained for cVMS materials. These differences may be attributed to environmental exposure and/or lipid partitioning differences between PCB180 and cVMS.

Mini-BLAST: computer systems to search for the pattern sequences in the bioinformatics databases

Bioinformatics focuses on developing and applying computationally intensive techniques to increase the understanding of biological processes. In this report we de- scribe the compact computer system Mini-BLAST, designed to find DNA sequences in bioinformatics databases placed in local or web configurations. Our system allows the identification of gene sequences relating to new patterns (metagenome) that are not yet identified in such databases, containing data on known nucleotides. Such a task is a quite expensive and time consuming operation; therefore, for large genomes parallel algorithms are required. We developed a user-friendly graphical interface that allows the simple input of query data and outputs representative statistical analysis. Additionally, users can select particular databases for cases when a specific alignment is required. Although the package is developed in MS .NET 3.5/4.0 Visual C# system, it works with no limitations in Linux through the Mono framework.

Maximal feeding with active prey-switching: A kill-the-winner functional response and its effect on global diversity and biogeography

Predators’ switching towards the most abundant prey is a mechanism that stabilizes population dynamics and helps overcome competitive exclusion of species in food webs. Current formulations of active prey-switching, however, display non-maximal feeding in which the predators’ total ingestion decays exponentially with the number prey species (i.e. the diet breadth) even though the total prey biomass stays constant. We analyse three previously published multi-species functional responses which have either active switching or maximal feeding, but not both. We identify the cause of this apparent incompatibility and describe a kill-the-winner formulation that combines active switching with maximal feeding. Active switching is shown to be a community response in which some predators become prey-selective and the formulations with maximal or non-maximal feeding are implicitly assuming different food web configurations. Global simulations using a marine ecosystem model with 64 phytoplankton species belonging to 4 major functional groups show that the species richness and biogeography of phytoplankton are very sensitive to the choice of the functional response for grazing. The phytoplankton biogeography reflects the balance between the competitive abilities for nutrient uptake and the degree of apparent competition which occurs indirectly between species that share a common predator species. The phytoplankton diversity significantly increases when active switching is combined with maximal feeding through predator-mediated coexistence.