Environmental Load Research Articles

The Impact of Differential Settlement on Sloshing Dynamics in Coastal Zone Storage Tanks Under External Excitation: Implications for Sustainable Development

Large storage tanks situated in coastal areas are vulnerable to environmental hazards, with earthquakes being one of the most destructive forces threatening their structural safety. Additionally, differential settlement can significantly alter conditions in the tank, including the inclination, thereby changing the direction of external applied excitation forces and affecting the liquid sloshing response. To investigate the coupled effects of structural settlement and external excitation, model tests were conducted in series to analyze liquid sloshing behavior in a tilted tank subjected to harmonic excitation. The results revealed that the liquid response under combined environmental loads displayed distinct characteristics compared with that under single excitation. While the inclination angle had minimal influence during the unstable sloshing stage, it became crucial during the stable stage, particularly for third-order resonant responses, leading to intensified sloshing. More specifically, as the tilt angle of the storage tank from 0° to 8°, the steady-state wave height at third-order resonance increased by approximately 69%. This highlights the amplified risks to the structural stability and safety posed by differential settlement. Furthermore, variations in steady-state wave heights due to differential settlement conditions were investigated. The water level elevation along the tank walls varies as the inclination angles increase, which leads to potential risks to the stability of liquid storage under forced motion, especially under symmetric structural designs, and increases the likelihood of structural instability, oil spills, and other coastal disasters. These results provide valuable insights into the safety risks and sustainable utilization of coastal infrastructure, serving a basis for assessing and mitigating the risks associated with structural settlement and seismic excitations.

A Damage Combination Method for Fatigue Analysis of Pressure Equipment in Floating Nuclear Power Plants

The operation of floating nuclear power plants is subject to a number of environmental factors in addition to the typical working temperature and pressure loads. These include marine environmental loads, which can cause fatigue damage and therefore must be taken into account. The fatigue analysis of marine structures frequently employs frequency domain methods, whereas the fatigue analysis of pressure equipment predominantly utilizes time-domain methods. At present, there is no comprehensive and accessible approach for conducting a fatigue analysis of pressure equipment in floating nuclear power plants. In light of the aforementioned considerations, this paper puts forth a novel approach to evaluating fatigue damage based on the principle of damage combination. This article presents a finite element model of pressure equipment and a methodology for calculating the transfer function of such equipment under wave loads. The frequency domain method is employed to calculate the fatigue damage caused by wave loads, with consideration given to both the working temperature and pressure load. The stress time history curve of pressure-bearing equipment is then calculated using the time-domain method. Subsequently, the fatigue damage caused by thermal pressure loads is obtained through a combination of the rainflow counting method and cumulative damage theory, with verification conducted using time-domain calculations. In comparison to alternative damage combination methodologies, the novel approach offers more precise and straightforward damage calculations, with promising potential for integration into engineering design.

Deep Reinforcement Learning‐Based Control for Real‐Time Hybrid Simulation of Civil Structures

ABSTRACTReal‐time Hybrid Simulation (RTHS) is a cyber‐physical technique that studies the dynamic behavior of a system by combining physical and numerical components that are coupled through a boundary condition enforcer. In structural engineering, the numerical components are subjected to environmental loads that become dynamic displacements of the physical substructure applied through an actuator. However, the dynamics of the coupling between components and the complexities of the system lead to synchronization challenges that affect the accuracy of the simulation. Thus, requiring tracking controllers to ensure the fidelity of the simulation. This paper studies deep reinforcement learning (DRL) as a novel alternative to designing the tracking controller. Three controllers are designed: a DRL agent combined with a conventional time delay compensation, a conventional feedback controller combined with a DRL agent, and a DRL agent with a complex neural network architecture. The proposed approaches are tested using a virtual RTHS benchmark problem, and the results are compared with an optimized controller that has a proportional‐integral‐derivative controller and phase‐lead compensation. The results show that DRL can address the synchronization challenges of RTHS with a model‐free approach and simple neural network architectures. The work shown in this study is a critical step toward model‐free control methodologies that can transform and further develop the RTHS method. The proposed methodology can be used to address important challenges related to RTHS, including nonlinearities and uncertainties of the physical substructure, complex boundary conditions, and the computational efficiency when physical structures with complex dynamics are present.

Development of Innovative Techniques for the Instrumentation of Composite and Wet on Wet Pavement Sections at MnROAD

Composite and wet on wet concrete pavements are a promising solution for the economical, sustainable and durable construction and renewal of highways. Wet-onwet pavements consist of Portland cement concrete (PCC)-over-PCC, with a relatively thin PCC layer placed wet on a wet thicker layer made of a less expensive PCC mixture. A composite pavement here will be referred to as, a relatively thin hot mix asphalt (HMA) layer placed over a less expensive PCC mixture. In order to acquire knowledge on the performance of these pavements, three heavily instrumented pavement sections were constructed at the Minnesota Road Research Facility (MnROAD) in May 2010. The purpose of the instrumentation is to establish the magnitude of the environmental loads that develop within these pavements and the response of the pavement to both these environmental loads as we as traffic loads. Without this, the development of a rational mechanistic-empirical design process is not possible. The instrumentation of PCC pavements constructed in two lifts has never been performed before and presents a surmountable challenge. Discussed below are novel instrumentation techniques that were developed to overcome these challenges.

A Review of Experiment Methods, Simulation Approaches and Wake Characteristics of Floating Offshore Wind Turbines

With the urgent demand for net-zero emissions, renewable energy is taking the lead and wind power is becoming increasingly important. Among the most promising sources, offshore wind energy located in deep water has gained significant attention. This review focuses on the experimental methods, simulation approaches, and wake characteristics of floating offshore wind turbines (FOWTs). The hydrodynamics and aerodynamics of FOWTs are not isolated and they interact with each other. Under the environmental load and mooring force, the floating platform has six degrees of freedom motions, which bring the changes in the relative wind speed to the turbine rotor, and furthermore, to the turbine aerodynamics. Then, the platform’s movements lead to a complex FOWT wake evolution, including wake recovery acceleration, velocity deficit fluctuations, wake deformation and wake meandering. In scale FOWT tests, it is challenging to simultaneously satisfy Reynolds number and Froude number similarity, resulting in gaps between scale model experiments and field measurements. Recently, progress has been made in scale model experiments; furthermore, a “Hardware in the loop” technique has been developed as an effective solution to the above contradiction. In numerical simulations, the coupling of hydrodynamics and aerodynamics is the concern and a typical numerical simulation of multi-body and multi-physical coupling is reviewed in this paper. Furthermore, recent advancements have been made in the analysis of wake characteristics, such as the application of instability theory and modal decomposition techniques in the study of FOWT wake evolution. These studies have revealed the formation of vortex rings and leapfrogging behavior in adjacent helical vortices, which deepens the understanding of the FOWT wake. Overall, this paper provides a comprehensive review of recent research on FOWT wake dynamics.

Quality of life in HIV patients treated at a primary care clinic: a cross-sectional study in Tobago

This study assessed the quality of life (QOL) among persons living with HIV (PLHIV) in Tobago using the WHOQOL-HIV-BREF and EuroQol EQ-5D-3L instruments, focusing on sociodemographic and clinical predictors. Conducted from October 2021 to March 2022 at the Tobago Health Promotion Clinic, it included 233 participants (average age 47.45 years; 46.2% male, 53.8% female). Results indicated significantly lower QoL compared to general norms, adjusted for age and sex. Negative predictors included opportunistic infections, detectable viral loads (environment domain P = 0.009, spiritual domain P = 0.002), aging, and government aid. Positive influences were stable relationships, higher income, longer antiretroviral therapy, female sex, non-heterosexuality, marriage, higher education, and employment (P < 0.05 for all). These findings emphasize the need for gender-sensitive interventions and enhanced social support to improve PLHIV’s QoL.

Sustainable Extraction Technology of Fruit and Vegetable Residues as Novel Food Ingredients.

Fruit and vegetable waste (FVW) is a global waste issue with environmental impacts. It contains valuable compounds such as polysaccharides, polyphenols, proteins, vitamins, pigments, and fatty acids, which can be extracted for food applications. This study aims to review sustainable extraction methods for FVW and its potential in the food industry. This paper provides an overview of the sources and sustainable methods of high value-added compounds extracted from FVW. Sustainable techniques, including supercritical fluid extraction and ultrasound-assisted extraction, are compared with traditional methods, for their efficiency in extracting high-value compounds from FVW while minimizing environmental impact. Sustainable extraction of FVW compounds is sustainable and beneficial for novel food ingredients. However, challenges in scalability and cost need to be addressed for wider adoption in the food sector. Sustainable extraction techniques effectively extract phytochemicals from FVW, preserving bioactivity and reducing environmental load. These methods show promise for sustainable food ingredient development.

Optimal Design and Operation of an Ultrasonic Driving System for Algae Removal Considering Underwater Environment Load.

This study investigates the optimal design and operation of an underwater ultrasonic system for algae removal, focusing on the electromechanical load of Langevin-type piezoelectric transducers. These piezoelectric transducers, which operate in underwater environments, exhibit variations in electrical-mechanical impedance due to practical environmental factors, such as waterproof molding structures or variations in pressure and flow rates depending on the water depth. To address these challenges, we modeled the underwater load conditions using the finite element method and analyzed the impedance characteristics of the piezoelectric transducer under realistic environmental conditions. Based on this analysis, we developed an ultrasound-driven system capable of efficient output control by incorporating the impedance characteristics of the transducer under load variations and subaquatic conditions. This study proposes analytical and experimental methods for modeling and analyzing practical ultrasound-driven systems for algae removal.

Indication of air pollution based on the comparison of mercury and other elements in the faeces of marmots from the Western Carpathians and the Dzungarian Alatau.

The Dzungarian Alatau in Central Asia and the Western Carpathians in Central Europe are exposed to anthropogenic sources of pollution that are impacting high-altitude mountain systems through long-range transport of emissions. Based on analyses of the autumn faeces of two species of marmots (Marmota baibacina from the alpine habitats of Zhongar Alatau National Park, Marmota marmota latirostris from the alpine habitats of the Western Tatras), we determined the environmental load of mercury and other chemical elements. Our results show significantly higher levels of total mercury amounts (p < 0.0001) in faeces of marmots from the Western Tatras, Slovakia (mean = 0.066 µg/g dry weight; SD = 0.43), than in Zhongar Alatau National Park, Kazakhstan (mean = 0.034 µg/g dry weight; SD = 0.01), as well as sulphur and heavy metals (Ba, Mn, Mo, Zn, Cu, and Cr) that originate from anthropogenic activities. Other significant differences in levels of mineral nutrients (K, Cl, Ca, Fe) and Sr rather indicate differences in food sources reflecting environmental factors.

Numerical Simulation Study on Hydrodynamic Characteristics of Offshore Floating Photovoltaics

With the development of renewable energy and the utilization of marine resources, large-scale offshore floating photovoltaics have gradually attracted widespread attention. In order to develop offshore floating photovoltaics and promote sustainable development, it has become necessary to explore the hydrodynamic characteristics of floating photovoltaic units and floating arrays. In this work, based on the viscous flow theory, the Computational Fluid Dynamics (CFD) and the discrete element method (DEM) methods are used to analyze the hydrodynamics of the floating body unit of offshore floating photovoltaics. The influencing factors include mooring length, mooring radius, and floating unit length. In addition, the hydrodynamic performance of the floating body unit and the floating body array under different wave heights and periods is also discussed to explore the influence of environmental loads on the floating body unit and the floating body array. The results indicate that the mooring tension exhibits an opposite trend with the surge and heave motions when the mooring line length and radius are varied. The motion is found to be more pronounced when the floating body unit length is 0.4 times the wavelength. The heave motion of the floating body unit exhibits a strong linear relationship with wave height, increasing by 0.01 m for every 0.015 m increase in wave height. The motion of the floating body units on both sides connected to the mooring lines decreases as the array length increases.

Optimum design, nonlinear dynamic response and vibration of graphene-reinforced laminated composite with negative Poisson’s ratio under dynamic load in thermal environment

Optimum design, nonlinear dynamic response and vibration of graphene-reinforced laminated composite with negative Poisson’s ratio under dynamic load in thermal environment

Performance degradation of glued-laminated timber beams under multi-factor environmental aging and sustained load

Performance degradation of glued-laminated timber beams under multi-factor environmental aging and sustained load

Achilles tendon morphology adaptations in chronic post-stroke hemiparesis: a comparative analysis with neurologically intact controls.

In individuals with chronic post-stroke hemiparesis, slow walking speed is a significant concern related to inadequate propulsion of the paretic limb. However, an overlooked factor is this population's altered morphology of the Achilles tendon, which may compromise the propulsive forces by the paretic limb. This study aimed to explore changes in Achilles tendon morphology, including gross thickness and intra-tendinous collagen fiber bundle organization, following stroke-induced brain lesions. Fifteen individuals with chronic post-stroke hemiparesis (at least 6 months post-stroke) and 19 neurologically intact controls participated. Ultrasound imaging was used to evaluate Achilles tendon thickness and collagen organization in the paretic and non-paretic limbs of post-stroke participants, as well as in the right limb (control limb) of the neurologically intact control group. Compared to control individuals, the paretic limb in individuals post-stroke showed increased tendon thickness at the Achilles tendon insertion and 2 cm above it. The collagen fiber bundle at the Achilles tendon insertion of the paretic limb showed reduced organization compared to that in the control limb. Individuals post-stroke also exhibited slower walking speed, and increased plantarflexor muscle tone in the paretic limb compared to controls. In conclusion, individuals with chronic post-stroke hemiparesis demonstrated tendon thickening and collagen disorganization in the paretic limb, particularly at the insertion site of the Achilles tendon, likely due to an abnormal loading environment influenced by increased plantarflexor muscle tone, muscle co-activation, and muscle disuse and atrophy. These changes may increase tendon compliance, impair force transmission and propulsion, and contribute to slower walking speed. Addressing Achilles tendon integrity should be incorporated as a component of strategies to improve neuromuscular control in this population.

Strength and fatigue analysis of mudline wellhead and its tie-back system in offshore drilling

This article presents a new operational approach for mudline wellheads, aimed at transforming exploration wells into development wells, thus reducing costs and construction time in marginal oil fields. It includes a fatigue life analysis of mudline wellhead systems and tie-back systems at different platform heights (20 m and 100 m). The study develops mechanical models to assess structural integrity under environmental loads such as wind, waves, and currents. Stress concentrations, especially at connection points, are analyzed to determine fatigue life. The study not only establishes the service life for both water depth scenarios but also offers structural optimization suggestions for the tie-back system. Incorporating marine environmental data, it provides a comprehensive strength and fatigue analysis, ensuring the structural safety of the mudline wellhead and tie-back system. This research underpins the economic viability of the mudline wellhead tie-back operation mode, contributing significantly to offshore drilling design, efficiency, and sustainability, marking progress in offshore engineering.

Structure failure and strength evaluation of honeycomb-based sandwich composites under variable hydro-thermal-mechanical load

The high-strength and lightweight sandwich structures have broad application prospect in aerospace, wind turbine generator, traffic and civil engineering. The sandwich structures usually service with severe environment and complicated mechanical load, structure failure and strength prediction are crucial issues. Under time-varying and optional position hydro-thermal–mechanical loading, this paper systematically analyzes strength failure, buckling and delamination of a sandwich beam with carbon fiber-reinforced polymer face sheet and aluminum honeycomb core. Effects of elastic boundary conditions, hydrothermal stress, configuration of honeycomb cell and thickness of face sheet on failure pattern and critical failure loading are evaluated. The theoretical deformation model is verified by performing a bending experiment of cantilever beam. For the honeycomb core with small re-entrant angle and shot horizontal cell wall, the sandwich cantilever beam occurs strength failure of face sheet and delamination is happened in simply supported beam. With increase of re-entrant angle and cell wall length, buckling of horizontal cell wall becomes the primary failure pattern of sandwich beam. With thickness increase of face sheet, the failure pattern switches from face sheet’s strength failure to delamination. The critical load for delamination decreases to a volley value and then increases with thickness of face sheet.

Research on the influence of environmental loads on the rheological properties of laterite nickel ore during liquefaction

Research on the influence of environmental loads on the rheological properties of laterite nickel ore during liquefaction

Dynamic estimation of the soil environmental carrying capacity for Benzo(a)pyrene in an industrial city, China: Insight from both duration and rate of regional emission.

An in-depth investigation of the maximum environmental load is crucial for soil security and pollution prevention. This research focused on soil environmental carrying capacity (SECC) for different risk receptors in a Chinese industrial city. By determining risk threshold for various land use types, we integrated mass balance and iterative models to capture dynamic net input fluxes with spatial heterogeneity. This enabled quantitative characterization of Benzo(a)pyrene (BaP) SECC through top-down and bottom-up approaches (corresponding to duration (D) and rate of regional emission, respectively). The thresholds were in the order of agricultural land<residential land<forest<industrial land<park. The top-down analysis showed D increased ∼1.5x with a 5% input flux decline until 2031. The bottom-up analysis suggested industrial emissions decreased by approximately 10% as the pollution control period was extended from 20 to 50 years. Both methods showed that at maximum background values (C0), D was ∼4x and the industrial emission rate was ∼10% higher than at minimum C0. SECC values near industrial areas significantly decreased, even reaching negative values, signifying complete carrying capacity loss. This study provided an approach to the dynamics of SECC under diverse scenarios, aiding informed decision-making for sustainable land management.

Appraising annual post-maintenance functional performance of asphalt roadway based on causal inference approach

ABSTRACT To maintain good functional pavement performance and extend the service life of asphalt pavements, the long-term performance of pavements under maintenance policies needs to be evaluated and favourable options need to be chosen based on the condition of the pavement. A major challenge in evaluating maintenance policies is to produce valid treatments for the outcome assessment under the control of uncertainty of vehicle loads and the disturbance of freeze-thaw cycles in the climatic environment. In this study, a novel causal inference approach, combining a classical causal structural model and a potential outcome model framework, is proposed to appraise the annual post-maintenance performance of four preventive preservation treatments of pavements for longitudinal cracking over a 5-year period of upkeep. Three fundamental issues were brought to our attention: detection of causal relationships prior to variables under environmental loading (identification of causal structure); obtaining direct causal effects of treatment on outcomes excluding covariates (identification of causal effects) and sensitivity analysis of causal relationships. The results show that the method can accurately evaluate the effect of preventive maintenance treatments, assess the maintenance time to cater well for the functional performance of different preventive maintenance approaches and develop appropriate maintenance strategies for pavements.

Development of smart films based on soy protein and cow horn dissolved in a deep eutectic solvent: Physicochemical and environmental assessment.

With the urge to reduce the use of petroleum-based materials, the aim of this work is to valorize biowaste to develop smart films through a sustainable fabrication way. In this regard, choline chloride/urea (1:2) deep eutectic solvent (DES) at different concentrations (25, 40, 50 and 75 wt%) was used to dissolve cow horn, used as reinforcement agent in soy protein films. The film fabrication was carried out by compression molding, a fast and cost-effective. As proved by SEM/EDX, cow horn was well-dispersed in the films, suggesting a homogeneous distribution of the sulfur from the cysteine present in keratin, the main component of cow horn. FTIR spectroscopy suggested interactions between the components of the formulation, which reduce the water uptake from 180 % to 140 %. Additionally, the films could be heat-sealed. With the aim of developing smart films, blueberry extract was incorporated into the formulation. This extract provided the films with pH sensitivity, which was followed by the film color change in presence of ammonia vapor. In particular, it is worth noting the ability of those films prepared with 40 wt% Horn/DES and 15 wt% blueberry extract to detect food spoilage. Finally, the environmental assessment of the films showed a minimal environmental impact of the procedure, with DES preparation and soybean production as the main relative contributors of the environmental load.

Feeding citrus pomace fermented with combined probiotics improves growth performance, meat quality, fatty acid profile, and antioxidant capacity in yellow-feathered broilers.

The reasonable and efficient utilization of agricultural by-products as animal feed has the capacity to not only mitigate the scarcity of conventional feedstuff but also alleviate the environmental load. This study was aimed to investigate the effects of feeding citrus pomace (CP) fermented with combined probiotics on growth performance, carcass traits, meat quality and antioxidant capacity in yellow-feathered broilers. A cohort of 540 female yellow-feathered broilers (Qingyuan partridge chicken, 90-day-old) were randomly divided into three groups and, respectively, fed the basal diet (Control), diet containing 10% unfermented CP (UFCP) and diet containing 10% fermented CP (FCP). The results showed that dietary FCP significantly increased (p < 0.05) the final-body-weight and average-daily-gain of broilers, and the pH45 min and b*24 h values in breast muscle, while tendentiously lowering the feed-to-gain ratio (p = 0.076). The levels of inosine monophosphate (p < 0.05) and intramuscular fat (p = 0.083) in the FCP group were higher than those in the control group. Remarkably, dietary FCP and UFCP increased the levels of polyunsaturated fatty acids (PUFAs) and n-6 PUFAs (p < 0.05). Moreover, dietary FCP decreased (p < 0.05) the malondialdehyde content and increased (p < 0.05) the glutathione peroxidase content in serum. Ingestion of FCP and UFCP increased the levels of total antioxidant capacity and catalase activity in serum, and concentrations of glutathione peroxidase and catalase in breast muscle (p < 0.05). Additionally, diet containing FCP or UFCP upregulated the expression of SREBP - 1c, FAS, NRF2, GSH-Px, and CAT in breast muscle (p < 0.05). Overall, dietary supplementation with FCP obviously improved meat quality, enhanced the antioxidant capacity and regulated the lipid metabolism, contributing to the improvement of growth performance of yellow-feathered broilers.