Structural Foundation Research Articles

Sustainable thin shell analysis on structural foundation subjected to seismic loads

Shell structures are recognized for their exceptional performance in withstanding compression forces, often utilized as roof components. However, Southeast Asia experiences significant annual losses due to floods, with inadequate structural mitigation despite high population concentrations in seismic risk areas. Previous research explored thin shell structures as elevated foundations to mitigate flood effects on buildings. Unfortunately, the proposed shell design exceeded the material’s strength limit of 40N/mm2, limiting its feasibility. To address this, our study proposes a modified thin shell with a 600mm thickness. Finite Element analysis using LUSAS software evaluated the new design’s structural behavior under dynamic loads from earthquakes and flood-induced waves. Results demonstrate a substantial reduction of up to 99% in equivalent stress compared to the previous model [Model P]. The revised model [Model C] proves feasible in withstanding intense building loads, ensuring maximum stress remains below the concrete material’s strength limit. Implementation of these findings offers valuable structural mitigation, reducing flood impacts and enhancing both structural resilience and human safety.

Co-exposure to low-dose lead, cadmium, and mercury promotes memory deficits in rats: Insights from the dynamics of dendritic spine pruning in brain development

Lead (Pb), cadmium (Cd), and mercury (Hg) are environmentally toxic heavy metals that can be simultaneously detected at low levels in the blood of the general population. Although our previous studies have demonstrated neurodevelopmental toxicity upon co-exposure to these heavy metals at these low levels, the precise mechanisms remain largely unknown. Dendritic spines are the structural foundation of memory and undergo significant dynamic changes during development. This study focused on the dynamics of dendritic spines during brain development following Pb, Cd, and Hg co-exposure-induced memory impairment. First, the dynamic characteristics of dendritic spines in the prefrontal cortex were observed throughout the life cycle of normal rats. We observed that dendritic spines increased rapidly from birth to their peak value at weaning, followed by significant pruning and a decrease during adolescence. Dendritic spines tended to be stable until their loss in old age. Subsequently, a rat model of low-dose Pb, Cd, and Hg co-exposure from embryo to adolescence was established. The results showed that exposure to low doses of heavy metals equivalent to those detected in the blood of the general population impaired spatial memory and altered the dynamics of dendritic spine pruning from weaning to adolescence. Proteomic analysis of brain and blood samples suggested that differentially expressed proteins upon heavy metal exposure were enriched in dendritic spine-related cytoskeletal regulation and axon guidance signaling pathways and that cofilin was enriched in both of these pathways. Further experiments confirmed that heavy metal exposure altered actin cytoskeleton dynamics and disturbed the dendritic spine pruning-related LIM domain kinase 1-cofilin pathway in the rat prefrontal cortex. Our findings demonstrate that low-dose Pb, Cd, and Hg co-exposure may promote memory impairment by perturbing dendritic spine dynamics through dendritic spine pruning-related signaling pathways.

Security beyond the state: exploring potential development impacts of community policing reform in post-conflict and fragile environment

ABSTRACT This study investigates the significance of understanding police perspectives on community policing as a means of addressing insecurity, particularly within the context of localised and asymmetrical conflicts. It highlights the pivotal role of the police in shaping community security and the substantial impact they can have (positive or negative) in fragile environments. The study contends that the localised nature of the community policing effectively addresses security and development issues and empowering citizens. Qualitative interviews were conducted with senior police in Islamabad, to assess the implementation and potential impacts of community policing in Pakistan’s Federal Capital Territory. The findings reveal how the historical foundations of police structures and operations – which date back to the colonial period – have led to the promotion of fear, mistrust and manipulation under successive regimes. Despite these challenges, the findings are promising highlighting enhanced human security through context-specific community policing. Finally, the paper argues that the movement towards community-oriented policing marks a departure from the control of elites within state systems, and encourages values such as local ownership, social cohesion, mutual engagement, accountability and agency. These developments have profound implications for global security and justice.

Suffusion in gap-graded granular soils subjected to strain-controlled cyclic loading with coupled CFD-DEM method

The suffusion mechanism of gap-graded soils subjected to cyclic loading, which is common in foundations of transportation engineering and marine structures, has not been fully understood. This paper employs the coupled computational fluid dynamics and discrete element method (CFD-DEM) to investigate the effect of cyclic loading on suffusion. The cyclic loading is simulated in a strain-controlled way, by which, samples with different frequencies (i.e., 0.5 Hz, 1 Hz, and 2 Hz) and strain amplitudes (i.e., 0.5 %, 1 %, 2 %) undergo erosion of 20 s duration with a constant hydraulic gradient and confining pressure. The influence of cyclic loading on suffusion is examined from both the macroscopic and microscopic perspective through the capture of erosion mass, void ratio variation, particle velocity field, fines trajectory, and force chain. Results indicate that the higher the cyclic frequency and strain magnitude, the more severe the loss of the fines. The vibratory compaction of dynamic loading could lead to the clogging of the sample, decreasing the hydraulic conductivity. In addition, the different micromechanisms of fines erosion during loading and unloading is presented.

The influence of the protective screen on stress -strain state of surrounding buildings in zone of new constuction

In this article, a study of the effectiveness of the use of a protective screen in densely built-up conditions was carried out. Based on numerical modeling, the impact of new construction on the stress-strain state of a three-story brick building was calculated. The problem was modeled in 2D and 3D settings with the input of the system "excavation structures of the pit - soil massif - protective screen - foundations of the existing building" At a distance of 4 m from the building, a pit with a depth of 6 m was excavated, as a fence of the pit, bored piles were used. The protective screen is made of piles of a metal pipe with a diameter of 159 mm, which was filled with concrete, the pitch of the piles was 0.2 m. Two tasks were solved: the installation of a pit with a protective screen between the retaining wall and the existing building and without a protective screen. The behavior of the soil mass was modeled using the Hardening Soil Model. The calculation was carried out in stages. At the first stage, the initial natural stress-deformed state of the soil massif was created. At the next stage, the operating load was transferred to the foundation structures of the building, after which the resulting deformations were zeroed. Next, piles were installed and the pit was developed step by step (in parts with a depth of 2 m). Regulatory documents declaring the limit values of additional deformations of bases and foundations in the area of compacted buildings and their dependence on the technical condition of the building were analyzed. The main causes of the deformation of the surrounding buildings in zone of influence of the new construction and measures to minimize the negative impact on the existing buildings have been established. It was found that the technology of piling the pit has a significant effect on the stress-strain state of the surrounding buildings. At the stage of drilling pile wells, additional subsidence of the foundations of the house is observed. The positive role of the protective screen in increasing the strength of the pit fence piles was also revealed. It was established that the protective screen allows to avoid an increase in the stresses of the foundations of the existing building and to limit the zone of deformation that occurs as a result of construction works.

Structure and Function of Kdac1, a Class II Deacetylase from the Multidrug-Resistant Pathogen Acinetobacter baumannii.

Proteomics studies indicate that 10% of proteins in the opportunistic pathogen Acinetobacter baumannii are acetylated, suggesting that lysine acetyltransferases and deacetylases function to maintain and regulate a robust bacterial acetylome. As the first step in exploring these fascinating prokaryotic enzymes, we now report the preparation and characterization of the lysine deacetylase Kdac1. We show that Kdac1 catalyzes the deacetylation of free acetyllysine and acetyllysine tetrapeptide assay substrates, and we also report the X-ray crystal structures of unliganded Kdac1 as well as its complex with the hydroxamate inhibitor Citarinostat. Kdac1 is a tetramer in solution and in the crystal; the crystal structure reveals that the L1 loop functions to stabilize quaternary structure, forming inter-subunit hydrogen bonds and salt bridges around a central arginine residue (R30). Surprisingly, the L1 loop partially blocks entry to the active site, but it is sufficiently flexible to allow for the binding of two Citarinostat molecules in the active site. The L12 loop is also important for maintaining quaternary structure; here, a conserved arginine (R278) accepts hydrogen bonds from the backbone carbonyl groups of residues in an adjacent monomer. Structural comparisons with two other prokaryotic lysine deacetylases reveal conserved residues in the L1 and L12 loops that similarly support tetramer assembly. These studies provide a structural foundation for understanding enzymes that regulate protein function in bacteria through reversible lysine acetylation, serving as a first step in the exploration of these enzymes as possible targets for the development of new antibiotics.

Experimental research on the lowering process of the three and four-bucket jacket foundation of offshore wind turbine

Whether or not the top of the multi-bucket jacket foundation is open during the lowering process affects the air-water replacement process in the bucket. The bucket's layout impacts the skirt effect, the shielding effect under the wave load, and the force during the lowering process. For four types of multi-bucket jacket foundations, the method of the experiment is adopted to study the influence of the foundation structure type, the lowering velocity, the perforation ratio of the top, and the initial air storage in the bucket on the foundation dynamic characteristics and response mechanism during the lowering process under the two construction methods of ventilation and active air storage. During the lowering operation of the top ventilation, the air pressure response trend of the three-bucket and four-bucket jacket foundation with the same size are consistent. The effect of the lowering velocity on the air cushion height in the bucket is greater than that of the perforation ratio. During the lowering process of active air storage, before the top cover is completely submerged, the air cushion height in the bucket basically increases linearly, and is stable when it continues to be lowered, and increases slightly at the landing on the seabed stage. The dynamic amplification factor (DAF) value and failure factor of the sling during the lowering process of the four kinds of multi-bucket jacket foundations all meet the design requirement. The initial air storage in the bucket can be between 5% and 15%.

Research on Bearing Difference between Single-Pile Composite Foundation Field Test and Group-Pile Composite Foundation of High-Rise Buildings

The reliability of high-rise buildings’ rigid-pile composite foundations primarily relies on the load test results of single-pile composite foundations. Field load tests were conducted for a high-rise building in the loess area of China, the results conformed to the design requirements. Nevertheless, the buildings experienced significant settlement after construction, which was quite different from the test results. Investigating bearing disparities between the single-pile and group-pile composite foundations in high-rise structures was necessary. Firstly, conducting an indoor interface shear test to propose a pile–soil hyperbolic contact model and integrate it into the numerical model. Subsequently, a finite element model was employed that accounts for pile–soil interactions in order to analyze discrepancies in bearing. The results show that the settlement difference rises by 56.4% as the load escalates by 100 kPa from the initial level and increases by 28.9% as the load ascends by 100 kPa to the final level. The settlement difference changes with an increasing load in a hardened curve pattern. Furthermore, differences in pile bearing characteristics and pile–soil interaction were analyzed. Negative friction occurs within 1/4 of the pile length within group-pile composite foundations, while in single-pile composite foundations, the range contracts to 1/10.

In vitro and in silico perspectives on the activation of antioxidant responsive element by citrus-derived flavonoids.

Oxidative stress plays an essential role in the pathogenesis of chronic diseases. Disrupting the Keap1-Nrf2 pathway by binding Keap1 is identified as a potential strategy to prevent oxidative stress-related chronic diseases. Therefore, of special interest is the utilization of dietary antioxidations from citrus, including narirutin, naringenin, hesperetin, hesperidin, naringin, neohesperidin dihydrochalcone, neohesperidin, and nobiletin, has been exploited as a prospective way to treat or prevent several human pathologies as Keap1-Nrf2 inhibitors for modulation of antioxidant properties. To probe into the structural foundation of the molecular identification of citrus-derived antioxidations, we calculated the antioxidant responsive element activation ability of citrus-derived flavonoids after binding with Keap1. Also, the quantum chemistry properties and binding mode were performed theoretically with frontier molecular orbitals, molecular electrostatic potential analysis, molecular docking, and absorption, distribution, metabolism, excretion (ADME) calculation. Experimental findings combining computational assays revealed that the tested citrus-derived flavonoids can be grouped into strong agonists and weak agonists. The citrus-derived antioxidations were well housed in the bound zone of Keap1 via stable hydrogen bonding and hydrophobic interaction. Eventually, three of eight antioxidations were identified after ADME and physicochemical evaluations. The citrus-derived flavonoids were identified as potential dietary antioxidants of the Keap1-Nrf2 interaction, and can be used to improve oxidative stress-related chronic diseases.

Combined rupture mechanism of shallow foundations under drained conditions

Current technical standards and codes of practice for shallow foundation design at the ultimate limit state require the analysis of rupture mechanisms that involve only the soil by assuming that the foundation structure does not undergo any yielding or rupture, but do not consider the case of combined rupture mechanisms in the soil and in the foundation structure, a situation that was recently observed in experiments on wind turbine foundations. By means of special numerical techniques for the analysis of soil–foundation interaction at the ultimate limit state under drained conditions, this work extends previous numerical investigations on undrained conditions and shows that the internal actions, the bearing contact pressures and the contact shear stresses beneath a yielding, flexible shallow foundation are much different with respect to those evaluated under undrained conditions. In any case, it is shown that foundation plasticisation leads to a potentially strong reduction of the bearing capacity depending on the loading condition. This work draws attention to some possible design situations that may be relevant for the optimised structural design of shallow foundations and paves the way to the development of simplified approaches that could be used in the usual design practice.

Structural Foundations for Improving Reliability and Durability of Machine Parts

Structural Foundations for Improving Reliability and Durability of Machine Parts

Host nutrient sensing is mediated by mTOR signaling in cnidarian-dinoflagellate symbiosis

To survive in the nutrient-poor waters of the tropics, reef-building corals rely on intracellular, photosynthetic dinoflagellate symbionts. Photosynthates produced by the symbiont are translocated to the host, and this enables corals to form the structural foundation of the most biodiverse of all marine ecosystems. Although the regulation of nutrient exchange between partners is critical for ecosystem stability and health, the mechanisms governing how nutrients are sensed, transferred, and integrated into host cell processes are largely unknown. Ubiquitous among eukaryotes, the mechanistic target of the rapamycin (mTOR) signaling pathway integrates intracellular and extracellular stimuli to influence cell growth and cell-cycle progression and to balance metabolic processes. A functional role of mTOR in the integration of host and symbiont was demonstrated in various nutritional symbioses, and a similar role of mTOR was proposed for coral-algal symbioses. Using the endosymbiosis model Aiptasia, we examined the role of mTOR signaling in both larvae and adult polyps across various stages of symbiosis. We found that symbiosis enhances cell proliferation, and using an Aiptasia-specific antibody, we localized mTOR to symbiosome membranes. We found that mTOR signaling is activated by symbiosis, while inhibition of mTOR signaling disrupts intracellular niche establishment and symbiosis altogether. Additionally, we observed that dysbiosis was a conserved response to mTOR inhibition in the larvae of a reef-building coral species. Our data confim that mTOR signaling plays a pivotal role in integrating symbiont-derived nutrients into host metabolism and symbiosis stability, ultimately allowing symbiotic cnidarians to thrive in challenging environments.

Synergy level of pollution and carbon reduction in the Yangtze River Economic Belt: Spatial-temporal evolution characteristics and driving factors

Achieving synergistic control of air pollution and carbon emissions is crucial for addressing environmental changes. This study aims to assess the synergy level of pollution and carbon reduction, identify driving factors, and provide realization paths to reduce pollution and carbon emissions synergistically. Using a coupling coordination degree model and optimal parameters-based Geographical detector model, this study focuses on 108 cities in the Yangtze River Economic Belt. Results reveal that PM2.5 control is more effective than carbon emission management in the YREB. The synergy level of pollution and carbon reduction shows an upward trend with the mean synergy level increasing 7.2% from 2006 to 2019. Spatially, significant heterogeneity exists, with higher synergy degrees in upstream areas. Social and natural factors including industrial structure, technological innovation, energy structure, human capital, and economic foundation significantly influence pollution and carbon reduction synergy. The interaction between natural constraints and high-quality development factors such as technological innovation and the digital economy further strengthens the driving force, with the strengthening of a single factor reaching up to 75%. Based on regional differences in synergy levels, this study proposes targeted applicable suggestions, including strengthening inter-city interaction, optimizing regional industrial and energy structures, and promoting technological innovation.

Evaluation of Influence of Seasonally Operating Cooling Devices on Thermophysical Processes of Soils of Railway Embankment Foundation

Construction in the regions of the Far North is characterised by numerous natural barriers, the presence of permafrost soils in the foundations of structures, the lack of infrastructure and extreme natural and climatic conditions. Thus, the most urgent task both in design and construction, and in further operation of transport infrastructure in the Arctic regions is to ensure reliability of the foundation of the structure.To ensure reliability of structures designed on permafrost soils, it is necessary to carry out thermophysical calculations and make forecasts of the influence of temperature processes on the foundation soils.The territory of the permafrost soils (PFS) occupies a large part of Russia, therefore, expanding the possibilities of using these regions for development of the transportation network is an important strategic task for the state. Today, in accordance with the Strategy for Spatial Development of the Russian Federation for the period up to 2025, the Arctic zone of the Russian Federation is a priority region in terms of economic growth and strategic impact.The article analyses the impact of the technology of seasonally operating cooling devices on the foundation soils of Salekhard- Nadym section of the Northern Latitudinal Railway line (Kilometre points 2825+00 - PK 2830+00). The effectiveness of seasonally operating cooling devices on permafrost soils of the railway embankment foundation is shown in combination with heat­insulating material. The advantages and disadvantages of seasonally operating cooling devices are summarised.

Construction of Rotation Channels for Pathogens Using the Repacking Method of Elements from Metamaterial Penetrated By Ultraviolet C Radiation

Our proposal involves a novel approach to fluid decontamination, targeting substances like aerosols, infected water, blood, and plasma. We aim to achieve this by employing a combination of repacking methods involving both large and small elements within a metamaterial. This strategy is formulated to generate rotational pathways that enhance the movement of pathogens in regions with elevated ultraviolet C radiation, specifically at a wavelength of around 260 nm. Through the utilization of two key mechanisms, repacking and centrifugal manipulation, we plan to create a groundbreaking decontamination method. In this procedure, we optimize the contact area by repacking a foundational structure made up of transparent spheres with smaller ones. Concurrently, we design helical channels resembling those found in centrifuges to manipulate pathogens such as viruses, bacteria, fungi, and aerosols within regions exposed to heightened ultraviolet C radiation. Our research reveals that as we reduce the size of the repacked components within the transparent metamaterial, the centrifugal force acting upon them intensifies. This effect directs pathogens and aerosols toward the evanescent region of the metamaterial, where the concentration of ultraviolet C radiation is elevated.

Offshore Wind Turbine Monopile Foundation Systems in Multilayered Soil Strata under Aerodynamic and Hydrodynamic Loads: State-of-the-Art Review

Due to the large demand to produce clean and renewable energy, offshore wind farms are extensively being used to help with economic development. Offshore Wind Turbine (OWT) structures are usually supported by various types of foundations and its selection depends on several factors such as water depth, economic costs, construction methodologies, seabed bathymetry, soil characteristics, and load characteristics. The present State-of-the-Art review focuses on OWT-monopile foundation systems embedded in multi-layered soil strata subjected to aerodynamic and hydrodynamic loading conditions. The purpose of this study is to carry out a comprehensive review on the performance of OWT-monopile foundation structures to support the design and drafting choices and thereby provide an understanding to reduce the costs. Two specific subject areas are addressed in this paper: (1) Factors affecting the performance of OWT-Monopile Foundation Systems; and (2) Experimental modeling and numerical analyses of OWT-Monopile Foundation Systems. The immediate challenge to the design of OWTs is to analyze the dynamic response of the foundation structure when exposed to both aerodynamic and hydrodynamic loads acting simultaneously. The limitations of the existing guidelines point to the need for improved design methods to obtain an economical design of OWT-monopile foundations. The use of Finite Element (FE) models is effective in studying the functioning of OWT-monopile structures. The present study suggests the development of further numerical models and modifications to the existing ones to properly assess soil-monopile interactions. This study also suggests further investigations on the design and analysis of OWT-monopile foundations considering the effect of (i) aerodynamic and hydrodynamic loading conditions with soil-monopile interactions, and (ii) multi-layered seabed characteristics.

Hard Tissue Augmentation - A Review

It has become possible to provide the structural foundation of osseous tissue needed to support dental implants using a number of methods and materials. Alveolar abnormalities with insufficient bone height and width have become a major concern with the introduction of dental implants.

Pile Group Effect Modeling and Parametric Sensitivity Analysis of Scoured Pile Group Bridge Foundations in Sandy Soils under Lateral Loads

Scour can increase the earthquake-induced damage in pile group foundations. Quantifying the parameter sensitivity of the seismic performance for scoured pile group foundations is essential for the optimal design and retrofit of bridges located in seismic-prone regions. Such quantification requires numerical models that are computationally efficient and accurate in describing the mechanical behavior associated with the complex soil–foundation–structure interaction of these systems. This study proposes an efficient finite-element model (FEM) of pile groups based on a beam on the nonlinear Winkler foundation approach. This FEM uses asymmetric p-multipliers to describe the different soil resistance exerted on leading and trailing piles when applying cyclic lateral loads. The proposed FEM is validated by comparing the numerical response with the experimental measurements taken from a quasi-static test available in the literature and is used to perform an extensive parametric sensitivity analysis to quantify the response sensitivity to 11 structural and soil parameters. Tornado diagrams are employed to identify an importance ranking of these parameters on the seismic performance of scoured pile groups. The obtained results indicate that the proposed FEM is able to capture both the global and local structural responses of pile group foundations. The parametric sensitivity analysis shows that pile group foundations have considerable ductility capacity. Pile diameter and axial load ratio of piles are the most important parameters for the seismic performance of pile groups. Increasing the pile diameter is the most efficient approach to improve the seismic performance of a pile group when considering scour effects. The seismic performance of a scoured pile group deteriorates with increasing piles’ axial load ratio. For a deep pile group foundation, seismic performance is very little sensitive to pile length and relative density of sand. Based on the results of the parametric analysis, recommendations are proposed for the seismic design of pile group foundations with scour effects.

ПРОГНОЗУВАННЯ НЕСУЧОЇ СПРОМОЖНОСТІ ПЛИТНОГО ФУНДАМЕНТА ЗА ЧИСЛОВИМ МЕТОДОМ ГРАНИЧНИХ ЕЛЕМЕНТІВ

Construction is one of the leading branches of the national economy in the historical aspect of its development. The first design task is to determine the strength of building structures. Therefore, the study of the stress-strain state and related calculations are the most important in construction. The purpose of studying soil mechanics and foundation construction techniques is the calculation and construction of structures on or in soil. The main task is the construction of structures with a sufficient degree of reliability.The selection of an adequate theoretical model remains the main problem of soil mechanics. Indeed, the deformation of the dispersed granular material of the soil takes place during the mutual sliding of the grains, the rheology of the soil is complex, as evidenced by a large amount of experimental material. Today, the path of development of soil mechanics is related to the study of problems within the framework of the elastic-plastic dilatation model and the improvement of this model based on experiments. A mathematical model of a technical object at the micro level is a system of differential equations in partial derivatives, the exact solution of which can be obtained only in a few partial cases, therefore a discrete model is built using numerical methods that use the Poisson idea that the behavior of a complex model can be represented by the behavior of its individual component elements. The intensive development and widespread use of computers significantly brought fundamental mathematical problems closer to applied ones, and strengthened their mutual influence.The emergence of a new, powerful and general method of research - a numerical experiment, more than ever before closely connected the physical content of the problem, its mathematical formulation, numerical methods of calculation and modern computers. The work uses the numerical method of boundary elements. A promising way to develop foundations and foundation structures is to use the ratios of the theory of plastic flow, and the level of development of soil mechanics significantly affects the economy and reliability of the decisions made.

Preschool Children's Loose Parts Play and the Relationship to Cognitive Development: A Review of the Literature.

Play is an integrative process, and the skills acquired in it-overcoming impulses, behavior control, exploration and discovery, problem-solving, reasoning, drawing conclusions, and attention to processes and outcomes are foundational cognitive structures that drive learning and motivation. Loose parts play is a prominent form of play that many scholars and educators explicitly endorse for cognitive development (e.g., divergent thinking, problem-solving). It is unique among play types because children can combine different play types and natural or manufactured materials in one occurrence. While educators and policymakers promote the benefits of loose parts play, no previous research has explored the direct relationship between preschool-age children's indoor loose parts play experiences and cognitive development. We address this gap by bringing together the relevant literature and synthesizing the empirical studies on common play types with loose parts, namely object and exploratory, symbolic and pretend, and constructive play. We also focus on studies that examine children's experiences through loose parts, highlighting the impact of different play types on learning through the reinforcement of cognitive skills, such as executive function, cognitive self-regulation, reasoning, and problem-solving. By examining the existing literature and synthesizing empirical evidence, we aim to deepen our understanding of the relationship between children's play with loose parts and its impact on cognitive development. Ultimately, pointing out the gaps in the literature that would add to the body of knowledge surrounding the benefits of play for cognitive development and inform educators, policymakers, and researchers about the significance of incorporating loose parts play into early childhood education.