Static Method Research Articles

Facile and efficient fabrication of carbon nanotube reinforced epoxy vitrimers through dynamic crosslinking

AbstractCarbon nanotubes (CNT) is an ideal candidate for reinforced epoxy vitrimer composites, however, achieving a desirable improvement of the mechanical properties is a great challenge owing to CNT is extremely easy to aggregate. In this study, well‐dispersed CNT reinforced epoxy vitrimers, namely EVD/CNT, were prepared by combining ultrasonic dispersion and dynamic crosslinking techniques, using multiple wall carbon nanotube as reinforcement filler, sebacic acid as curing agent, diglycidyl ether of bisphenol A (DGEBA) as epoxy monomer, zinc acetylacetonate as transesterification catalyst, torque rheometer (internal mixer) as dynamic crosslinking equipment. The CNT reinforced epoxy vitrimers, namely EVS/CNT, were prepared using traditional static curing method. The structure and morphology, mechanical properties and stress relaxation behavior of EVS/CNT and EVD/CNT were comparatively investigated, and the influence of CNT content on the structure and properties of EVD/CNT prepared by dynamic crosslinking method were also studied. The results indicated that dynamic crosslinking technology can stably disperse CNT into epoxy vitrimer resin matrix under continuous shear force. However, CNT experienced severe secondary agglomeration during the static curing process. When the loading amount of CNT was 2 wt%, the tensile strength and elongation at break of EVD/CNT‐2 were 3.2 times and 2.2 times higher than those of EVS/CNT‐2, respectively. The Young's modulus and glass transition temperature (Tg) of EVD/CNT‐2 (6.43 ± 1.10 MPa, 29.6°C) were also higher than those of EVS/CNT‐2 (5.46 ± 0.31 MPa, 25.4°C). Moreover, dynamic crosslinking technology greatly shortened the reaction time of CNT reinforced epoxy vitrimers, improved production efficiency and reduced reaction energy consumption, and was expected to be used for large‐scale and industrial production.

Returning Cropland to Grassland as a Potential Method for Increasing Carbon Storage in Dry-Hot Valley Areas

A key aspect of mitigating global climate warming is enhancing the carbon storage capacity of terrestrial ecosystems. China’s Grain for Green Program (GFGP) is the largest ecological restoration project in the world, which is closely associated with land use change. A systematic assessment of the GFGP’s impact on regional carbon storage is of great significance for promoting regional development and maintaining ecosystem stability. Therefore, this study selects a typical dry-hot valley area—Yanjin County—as the study area, which serves as an ecological protection barrier in Southwest China. We employed the InVEST model and Geo-detector model based on land use data from three periods (2000, 2014, and 2019), combined with static overlay analysis methods, in order to evaluate the impact of the implementation of GFGP on the spatial and temporal distribution of carbon storage. We also explored the driving factors of the spatial differentiation of carbon storage. The results indicate that, since the implementation of the GFGP, a total of 180.03 km2 of cropland has been converted to forestland, increasing the forest cover rate from 81.83% to 83.37%. The project has contributed 5.88 × 105 t to regional carbon storage, effectively offsetting carbon emissions caused by human activities such as urban expansion while also promoting the growth of regional carbon storage. The implementation of the GFGP has led to changes in three types of land use. Among them, converting cropland to forestland (3262 t/km2) is the most effective carbon sequestration method, and converting cropland to grassland (2530 t/km2) has shown great potential in carbon sequestration. Additionally, the study found that elevation (0.038–0.059) is the main factor affecting the spatial differentiation of carbon storage, and the interaction between elevation and other factors can effectively enhance the carbon sequestration capacity of regional ecosystems. Overall, the GFGP not only plays a significant role in combating climate warming but also makes an important contribution to improving the stability and sustainability of regional ecosystems.

Innovative approach to estimate structural damage using linear regression and K-nearest neighbors machine learning algorithms

Conventional structural design methodologies often utilize elastic analysis techniques, such as the equivalent static force method and the response spectrum method. While these methods are known for their simplicity and computational efficiency, they prove inadequate in capturing the extent of structural damage caused by seismic forces. Additionally, employing nonlinear dynamic analysis to estimate structural damage represents a challenging and intricate task, posing difficulties for many structural designers. Consequently, the objective of this paper is to present an innovative methodology for evaluating seismic structural damage of moment-resisting frame structures. This involves the utilization of machine learning algorithms, which have been trained and tested on a large data set generated using a newly developed and numerically efficient simulation procedure. The machine learning algorithms employ both linear regression and K-nearest neighbors approaches to accurately replicate the Park-Ang structural damage index.

Experimental Study on Automated Controller of Street Light Management System using IoT

In order to ensure public safety and support nighttime activities, street lighting is crucial to the urban landscape, and this study starts by contextualizing its importance. It then goes on to analyze the shortcomings of the current street lighting systems, which are typified by their static control methods and poor environmental response.These shortcomings underscore the urgent need for a paradigm shift towards more intelligent and adaptive solutions. The core proposition of this project lies in the design and implementation of an advanced street light management system empowered by IoT technology. At its heart, the system comprises a sophisticated network of interconnected devices, including sensors, actuators, and a central control unit. These components collaborate synergistically to capture, analyze, and act upon real-time data gleaned from the surrounding environment. Through the application of cutting-edge data analytics and machine learning algorithms, the system autonomously adjusts lighting levels in accordance with fluctuating parameters such as ambient light levels, traffic density, weather conditions, and pedestrian activity. By dynamically optimizing energy usage while ensuring adequate illumination, the system not only enhances operational efficiency but also contributes to cost reduction and environmental sustainability. Moreover, the proposed system incorporates proactive maintenance features, enabling early fault detection and remote diagnostics. This capability minimizes downtime and enhances system reliability, thereby mitigating the operational challenges associated with traditional street lighting infrastructure. The project further explores the conceptual framework of IoT, elucidating its transformative potential in revolutionizing urban infrastructure management. By seamlessly integrating physical devices with digital intelligence, IoT facilitates the creation of interconnected ecosystems wherein data-driven decision-making and automation converge to drive unprecedented efficiency and innovation

Study on the preparation of SiC–C–t‐ZrO2 composites and its corrosion resistance to crushed after‐used lithium batteries

AbstractIn order to solve the severe erosion of kiln refractories for the high‐temperature treatment used during the process of recovering valuable metal elements from waste lithium batteries, this study investigates the low‐cost, no‐firing preparation technology of erosion‐resistant SiC–C–t‐ZrO2 composites with self‐prepared t‐ZrO2–SiC–C powder, as well as silicon carbide and flake graphite as the main raw materials, and phenolic resin as the binding agent. (1) The effects of different t‐ZrO2–SiC–C powder additions and heat treatment temperatures on the properties of SiC–C–t‐ZrO2 composites were studied in details. (2) The erosion resistance of SiC–C–t‐ZrO2 composites to after‐use lithium battery waste was evaluated using the static crucible method. The mechanical properties of the t‐ZrO2–SiC–C composites was the best that its cold modulus of rupture (CMOR) was 11.37 MPa and cold crush strength (CCS) was 41.96 MPa when heat treatment temperature was 600°C and content of t‐ZrO2–SiC–C powder was 10 wt%. At that condition, the bulk density of samples reached to 3.15 g/cm3 and apparent porosity of it was only at 11.09% which means that the samples designed in this work are compacted enough. In the erosion test, the t‐ZrO2–SiC–C composites had an excellent resistance to erosion of lithium battery waste.

Multi-AUV underwater static target search method based on consensus-based bundle algorithm and improved Glasius bio-inspired neural network

This research introduces a hierarchical strategy for static target searches with multi-autonomous underwater vehicles (AUVs) to optimize cumulative search rewards. The approach comprises two primary elements: task allocation and path planning. A Voronoi diagram segments regions based on peak detection via a maximum filter in the task allocation stage. Then, a consensus-based bundling algorithm ensures the load-balanced distribution of peak sub-regions across AUVs, while a dynamic cooperation mechanism allows for dynamic adjustment of task allocation, thereby increasing the system's operational flexibility. Path planning employs an improved Glasius bio-inspired neural network, leveraging analogies to convolution processes and incorporating mean pooling, multiple convolutions, and resampling. This method enhances global information propagation and optimizes path point selection through a discounted reward function evaluating adjacent nodes, thus boosting the search efficiency of individual AUVs. Simulation experiments validate the method's effectiveness and robustness in multi-AUV static target searches, demonstrating its potential to improve search efficiency.

Fabrication of melamine formaldehyde/graphene oxide composite for efficient static and dynamic adsorption of lead ions from aqueous medium.

The present work discusses the synthesis, characterization, and environmental applications of graphene oxide (GO), melamine formaldehyde resin (MF), and melamine formaldehyde/graphene oxide composite (MGO) for the efficient removal of Pb2+ from aqueous medium via batch and column procedures. TGA, XRD, TEM, zeta potential, nitrogen adsorption/desorption, ATR-FTIR, and other characterization techniques revealed that MGO is characterized by a greater surface area (609 m2/g), total pore volume (1.0106 cm3/g), pHPZC (6.5), and the presence of various surface chemical functional groups. The synthesized solid adsorbents were used in both static and dynamic adsorption processes to remove Pb2+, with varying application parameters such as pH, starting concentration, adsorbent dosage, and shaking time in the case of static adsorption method. While through the column adsorption process the effects of column bed height, flow rate, and starting Pb2+ were taken into consideration. Results of the batch adsorption demonstrated that MGO had the highest Langmuir adsorption capacity (201.5 mg/g), and the adsorption fit the nonlinear Langmuir adsorption model and Elovich kinetic models. The adsorption of Pb2+ onto all prepared solid materials is endothermic, spontaneous, and physical in nature, as demonstrated by thermodynamic studies. Column adsorption of Pb2+ well fitted by Thomas and Yoon Nelson nonlinear adsorption models. MGO showed a maximum column adsorption capacity of 168 mg/g when applying 4 cm, 15 mL/min, and 150 mg/L as bed height, flow rate, and initial Pb2+, respectively. With only a 12.6% reduction in its adsorption capacity, column regeneration showed that MGO exhibited a high degree of reusability even after five cycles of adsorption/desorption studies.

Integrated geo-techno-economic and real options analysis of the decision to invest in a medium enthalpy deep geothermal heating plant. A case study in Northern Belgium

Deep geothermal energy (DGE) is a renewable energy source that is considered to cause a low global warming impact. The potential of DGE for heating is widespread and interest in deep geothermal heating (DGH) has been growing in Europe to help achieving the decarbonization of the heating mix. Nevertheless, despite its large potential, DGH development in Europe remains underexplored. DGH investments are hindered by the risks born by geological and market uncertainties. However, various flexibility options inherent to the development process, such as the option to abandon or defer, could partly mitigate these risks. To account for managerial flexibility in the investment analysis, this study suggests a novel real options (RO) framework. The RO model splits DGH development into five phases, and considers several compound options and geological and market uncertainties to investigate the timing and value of DGH development at the Campine Basin in Northern Belgium. The RO model is coupled to a geo-techno-economic model and is solved using the Least Squares Monte Carlo algorithm. The RO analysis finds a 51% probability of abandonment and an average deferral time for the development of 12 years. The abandon option mitigates the risk of large financial losses in case of inadequate geological conditions. The defer option allows the investors to wait for more favorable market conditions before investing, to increase the project value. The results show that DGH development in the investigated area is not economically desirable. However, the investors' flexibility increases the project value by 12.16 million EUR, compared to a conventional techno-economic analysis. The implementation of supporting policy measures improves the economic performance of the plant. The consideration of flexibility leads to supporting policy measures with 3–4 times lower governmental expenditure, compared to a conventional techno-economic analysis. This study shows that a RO approach is more suitable to investigate DGH investments than static techno-economic methods. The inclusion of flexibility allows for identifying development pathways that increase the project value and for designing more cost-efficient supporting policy schemes.

Innovative Brace Damper System for Mitigating Seismic Response in High-Rise Steel Structures

This study investigates the seismic response of a G+14 steel frame building with composite columns using fluid viscous dampers. The effectiveness of these dampers is assessed through analysis employing the Equivalent Static Method, Response Spectrum Method, and Time History Analysis in ETABS. Results indicate a significant 40–60% reduction in displacement and storey drift, underscoring the efficacy of fluid viscous dampers in enhancing structural resilience. This research underscores the importance of innovative damping systems in mitigating seismic risks in tall steel buildings.

Effect of positioning of shear walls in a multi-storied building on response to earthquake

Seismic events are a matter of concern for structural engineers because of their devastating effects. These events are neither can be predicted. nor can be prevented. To mitigate its impacts on the structures several measures are taken. But none of them can be treated as 100% effective, there is a lot of scope for improvement. In this study, the dynamic behavior of structures under seismic loading was investigated, focusing on the combined influence of geometric shapes, different types of shear walls, and their position on lateral displacement and drift. Specifically, four different geometric shapes of plans of identical floor areas were taken for this study. Two types of shear walls, oupled shear walls, and core shear walls were placed in four different positions. The Static Equivalent Load method to assess the seismic response of structures is employed in this study, following the guidelines given in the Bangladesh National Building Code 2006 using ETABS software. Key findings of the study are the efficacy of shear walls in mitigating lateral displacement. The optimum results were achieved for central positions and core wall configurations. The study discloses the significance of different geometric shapes on seismic responses. This study provides a perception of effective seismic retrofitting strategies.

The chemical and optical stability evaluation of injectable restorative materials under wet challenge

ObjectivesTo investigate and compare the chemical and optical stability of four restorative composite materials: two injectable resins, one flowable resin and one compomer. MethodsTwo injectable nano-filled composite resins: G-aenial Universal (GU) and Beautifil Injectable XSL (BI), a flowable composite resin: Filtek Supreme Flowable (FS) and a compomer: Dyract Flow (DF), in A2 shade were tested and compared. Water sorption and solubility were conducted according to ISO4049:2019 standard; ICP-OES and F-ion selective electrode were used to test the elemental release; Degree of conversion (DC) was obtained by using FTIR; water contact angle was obtained by static sessile drop method, and a spectrophotometer was used for optical properties (ΔE⁎, ΔL⁎ and TP). SPSS 28.0 was used for statistical analysis and the significant level was pre-set as α = 0.05. ResultsGU performed the best in water sorption and solubility, FS had the lowest elemental release, the best colour stability, and the highest DCIM and DC24-h. DF, the compomer had the lowest, and GU and BI, the injectable composites had the largest water contact angle, respectively. Correlations were found between water sorption and water solubility. ConclusionsThe four composite restorative materials showed different chemical and optical behaviours. Overall, composite resins performed better than compomer, while additional laboratory and in vivo tests are necessary to obtain a more comprehensive comparison between injectable and flowable composite resins. Wsp and Wsl are influenced by many common factors, and the values are highly positively related. Clinical SignificanceA comprehensive understanding of materials is crucial before selecting materials for clinical practice. Composite resins rather than compomers are recommended because of their exceptional properties, which make them eligible for a wide range of clinical applications and an elongated lifespan.

Active site remodeling in tumor-relevant IDH1 mutants drives distinct kinetic features and potential resistance mechanisms

Mutations in human isocitrate dehydrogenase 1 (IDH1) drive tumor formation in a variety of cancers by replacing its conventional activity with a neomorphic activity that generates an oncometabolite. Little is understood of the mechanistic differences among tumor-driving IDH1 mutants. We previously reported that the R132Q mutant unusually preserves conventional activity while catalyzing robust oncometabolite production, allowing an opportunity to compare these reaction mechanisms within a single active site. Here, we employ static and dynamic structural methods and observe that, compared to R132H, the R132Q active site adopts a conformation primed for catalysis with optimized substrate binding and hydride transfer to drive improved conventional and neomorphic activity over R132H. This active site remodeling reveals a possible mechanism of resistance to selective mutant IDH1 therapeutic inhibitors. This work enhances our understanding of fundamental IDH1 mechanisms while pinpointing regions for improving inhibitor selectivity.

Laboratory Evaluation of Strength Performance of Full-Depth Reclamation with Portland Cement Material

Laboratory Evaluation of Strength Performance of Full-Depth Reclamation with Portland Cement Material

Reinventing shake flask fermentation: The breathable flask.

Cultivating cells in shake flasks is a routine operation that is largely unchanged since its inception. A glass or plastic Erlenmeyer vessel with the primary gas exchange taking place across various porous plugs is used with media volumes typically ranging from 100 mL to 2 L. Oxygen limitation and carbon dioxide accumulation in the vessel is a major concern for studies involving shake flask cultures. In this study, we enhance mass transfer in a conventional shake flask by replacing the body wall with a permeable membrane. Naturally occurring concentration gradient across the permeable membrane walls facilitates the movement of oxygen and carbon dioxide between the flask and the external environment. The modified flask called the breathable flask, has shown a 40% improvement in mass transfer coefficient (kLa) determined using the static diffusion method. The prokaryotic cell culture studies performed with Escherichiacolishowed an improvement of 28%-66% in biomass and 41%-56% in recombinant product yield. The eukaryotic cell culture study performed with Pichia pastoris expressing proinsulin exhibited a 40% improvement in biomass and 115% improvement in protein yield. The study demonstrates a novel approach to addressing the mass transfer limitations in conventional shake flask cultures. The proposed flask amplifies its value by providing a membrane-diffusion-based sensing platform for the integration of low-cost, noninvasive sensing capabilities for real-time monitoring of critical cell culture parameters like dissolved oxygenand dissolved carbon dioxide.

An innovative booster-assisted dynamically installed fish anchor and its installation characteristics considering the action of ocean currents

The fish anchor is an economically viable offshore foundation engineering technology that has been proposed in recent years. By fish anchor, we mean a fish-shaped dynamically installed anchor that can penetrate into the seabed through water by its own weight. However, the existing research studies seldom consider the hydrodynamic characteristics of its free fall installation, resulting in uncertainties regarding its underwater installation characteristics. Therefore, based on OpenFOAM, this study first investigated the directional stability of fish anchors during its underwater falling process through the static model analysis method and dynamic model analysis method. The findings indicated that the directional stability of fish anchors was insufficient, rendering them suitable only for release and installation at low heights (i.e., less than 4.2 times the anchor length) without marine environmental loads. Furthermore, the anchor inclination angle during installation is significant, thereby impacting its penetration depth and pull-out capacity in the seabed. To solve this problem, the concept of an innovative booster-assisted fish anchor is proposed, which can significantly enhance the directional stability of conventional fish anchors. Results show that the maximum installation height of the new booster-assisted fish anchor is increased by 2.4 times compared to the original design, thereby enhancing both the penetration speed and uplift capacity. Based on the findings, recommended installation and construction conditions are provided. Finally, a predictive formula for the installation height and verticality of the new booster-assisted fish anchor under current action is presented to offer guidance for engineering applications.

Hydrodynamic and bearing behaviors of two typical deepwater dynamically installed anchors: torpedo anchor and fish anchor

Dynamically installed anchors, such as torpedo and fish anchors, are innovative and cost-effective anchorage foundations. In this study, the advantages and disadvantages of these two types of dynamically installed anchors are discussed by comparing the hydrodynamic and bearing characteristics of torpedo and fish anchors commonly used in practical engineering. First, based on OpenFOAM, 3D numerical models were established to investigate the directional stability and simulate the underwater free-fall process of anchors using static and dynamic model analysis methods. Using the validated model, the hydrodynamic performances (i.e., inclination angle, installation offset distance, penetration velocity, and drag coefficient) of torpedo and fish anchors were explored and compared. Based on these findings, the installation height of each anchor was recommended. Finally, the bearing performances of the torpedo and fish anchors were investigated using ABAQUS, and the selection principles of these two types of dynamically installed anchors were presented based on their hydrodynamic and bearing behaviors.

Numerical simulation of fluid-thermal-structural coupling characteristics of stratospheric non-rigid airship

The voluminous stratospheric non-rigid airship is very sensitive to the external thermal environment. The temperature change of internal gas caused by the variation in the external thermal environment and wind speed will lead to a change in the shape and buoyancy of the airship, thereby affecting its flight control. The traditional static analysis method is difficult to accurately reflect this fluid-thermal-structural coupling process. In this paper, the iterative analysis method was established for the fluid-thermal-structural coupling effect of stratospheric non-rigid airship based on the models of fluid, thermal, and structural deformation. Considering the load such as the internal thermal effect and external flow field of the airship, the simulation of the thermo-induced structural deformation effect was conducted using Fluent and Abaqus software. The influence of local time and external wind speed on the structural deformation, volume, and equilibrium altitude of the airship was analyzed. The results demonstrate that, at low wind speed, the influence of aerodynamic pressure on the deformation of the airship is negligible. However, a great amount of heat is carried away by the wind, then the structural deformation caused by internal and external pressure difference is alleviated and the equilibrium altitude of the airship change obviously. This can serve as a guideline for the design and flight test of the long-endurance stratospheric non-rigid airship.

A CRITICAL EVALUATION OF SECURITY APPROACHES FOR DETECTION AND PREVENTION OF SQL INJECTION ATTACKS IN WEB-BASED APPLICATIONS

SQL Injection Attack (SQLIAs) is a web application attack that has been known for almost two decades, and that has been among the biggest cyber threats especially because most of the world’s population interacts with web apps in one way or the other. Over the years many methods have been developed to identify and deter SQLIAs, thereby reducing the risk on web applications. Four various methods used to identify and stop SQLIAs are reviewed, compared and critically evaluated in this paper, these include tokenization and lexicon detection process, combined static and dynamic method, novel, and search-based methods. This work further reveals the gap in current knowledge, specifically, increased efficiency can be achieved by integrating two of the most effective approaches. Furthermore, a real-world application of these methods is presented and finally, recommendations are made for further study.

Analysis of Base Shear and Story Drift in the Low-Rise RC Sructure

<p class="Abstract">Earthquakes frequently occur in Indonesia because it is an earthquake-prone area. Due to lateral load from an earthquake can cause a weakly constructed building to collapse. Designers often only consider tall buildings in designing earthquake-resistant building structures but ignore earthquake-resistant designing for low-rise buildings. This study focuses on the analysis of earthquake resistant structures with a case study of low-rise buildings in the form of a 3-story reinforced concrete (RC) building in the South Jakarta area. The objective of the study is to analyze the base shear and story drift of the structure due to lateral or earthquake loads. The structure is a reinforced concrete with the concrete compressive strength of <em> </em>= 30 MPa and longitudinal reinforcement of = 420 MPa and stirrups of = 280 MPa. This study uses equivalent static analysis manually and using ETABS 20.1.0 application. The results showed that three story buildings analyzed using equivalent static analysis method and using ETABS 20.1.0 application had almost the same results on horizontal forces with manual result of 1680.97 kN and ETABS of 1648.46 kN. The elastic story deflection and inelastic story drift in this study are still within safe limits because it is below the drift limit.</p>

Modeling heterogeneous and adaptive homeowners’ decision-making for green retrofit

Green retrofitting (GR) of existing residential buildings is widely acknowledged as a potential solution for addressing climate and energy challenges. However, the realization of GR potential depends on homeowners’ decision-making, as they play a pivotal role in initiating GR and are the primary users of retrofitted homes. Previous studies have explored homeowners’ GR decisions from various perspectives. The majority of these studies may have encountered limitations, such as the use of static analysis methods, homogeneity assumptions, and oversimplified decision processes. These limitations can potentially hinder a comprehensive understanding of homeowners’ GR adoption, indicating the need for further research. To address this research gap, this study develops a decision-making model for homeowners that incorporates multiple dimensions: heterogeneity (e.g., individual attributes and GR motivations), a multi-stage decision process (needs-utility-willingness-adoption), and dynamic adaptability (both at individual and overall networks). The proposed model is empirically validated through Python simulations based on a case study in China. The findings of this study reveal the critical roles of GR needs, perceived (actual) utility, and perceived behavioral control in homeowners’ adoption of GR. Moreover, this study highlights the significance of coordinating homeowners’ overall perceived utility with the specific sub-utility associated with their motivations. Furthermore, empirical evidence underscores the influence of social factors on GR adoption and emphasizes the existence of gaps across different stages of the decision-making process. Drawing from these research findings, policy implications are proposed for promoting housing GR. This research contributes to the advancement of decision models for building GR and provides valuable insights for policymakers to promote housing GR.