Laboratory Experiments Research Articles

Integrated drag coefficient formula for estimating the wave attenuation capacity of Rhizophora sp. mangrove forests

Recently, bulk drag coefficient (C˜D) formulations used to quantify wave energy dissipation by Rhizophora mangroves were developed from laboratory data; however, these formulations have not yet been validated with field data. Additionally, due to the complex geometry of mangrove trees within forests and spatial variability, common criteria for determining the adequate geometric characteristics of mangrove forests are lacking and are required to obtain accurate definitions for C˜D. This paper addresses these knowledge gaps by proposing a newly integrated C˜D formulation based on the comprehensive characterization of a Rhizophora mangle forest combined with wave measurements in field, and by using numerical modeling for the calibration process. The field campaign consisted of 23 continuous days of recorded wave data and spatial distribution observations of the geometric characteristics of the mangrove forest. The variation in frontal area per unit height per square meter (Ahm) along the mangrove forest was reported for three zones with different densities identified along the study transect, with decreasing root density from the vegetation edge to the forest interior. On average, the incident wave height decreased by 34% at 63 m in mangrove forests, and the wave attenuation ratios (r) varied between 0.001 and 0.01 m-1. To estimate the C˜D values associated with these wave height attenuation ratios, the Simulating Waves Nearshore (SWAN) numerical model was used to calibrate the model results with the field observations. The variation in the tree frontal area along the mangrove forest and the wave conditions at the site are considered during the calibration process. To further characterize C˜D for this type of mangrove species, the C˜D values acquired from the calibration together with the values reported in the literature from laboratory experiments are presented as a function of the Keulegan-Carpenter number (KC). Root diameter is defined as the characteristic length according to the inherent geometric characteristics of a Rhizophora sp. forest. The new formulation allows us to predictably estimate C˜D values that can be used as inputs in drag force-based models to estimate the attenuation of wave energy produced by Rhizophora sp. forests.

Predicting the impact of adding metakaolin on the splitting strength of concrete using ensemble ML classification and symbolic regression techniques –a comparative study

The mechanical characteristics of concrete are crucial factors in structural design standards especially in concrete technology. Employing reliable prediction models for concrete’s mechanical properties can reduce the number of necessary laboratory trials, checks and experiments to obtain valuable representative design data, thus saving both time and resources. Metakaolin (MK) is commonly utilized as a supplementary replacement for Portland cement in sustainable concrete production due to its technical and environmental benefits towards net-zero goals of the United Nations Sustainable Development Goals (UNSDGs). In this research work, 204 data entries from concrete mixes produced with the addition of metakaolin (MK) were collected and analyzed using eight (8) ensemble machine learning tools and one (1) symbolic regression technique. The application of multiple machine learning protocols such as the ensemble group and the symbolic regression techniques have not been presented in any previous research work on the modeling of splitting tensile strength of MK mixed concrete. The data was partitioned and applied according to standard conditions. Lastly, some selected performance evaluation indices were used to test the models’ accuracy in predicting the splitting strength (Fsp) of the studied MK-mixed concrete. At the end, results show that the k-nearest neighbor (KNN) outperformed the other techniques in the ensemble group with the following indices; SSE of 4% and 1%, MAE of 0.1 and 0.2 MPa, MSE of 0, RMSE of 0.1 and 0.2 MPa, Error of 0.04% and 0.04%, Accuracy of 0.96 and 0.96 and R2 of 0.98 and 0.98 for the training and validation models, respectively. This is followed closely by the support vector machine (SVM) with the following indices; SSE of 7% and 3%, MAE of 0.2 and 0.2 MPa, MSE of 0.0 and 0.1 MPa, RMSE of 0.2 and 0.3 MPa, Error of 0.05% and 0.06%, Accuracy of 0.95 and 0.94, and R2 of 0.96 and 0.95, for the training and validation models, respectively. The third model in the superiority rank is the CN2 with the following performance indices; SSE of 15% and 4%, MAE of 0.2 and 0.2 MPa, MSE of 0.1 and 0.1 MPa, RMSE of 0.3 and 0.3 MPa, Error of 0.08% and 0.07%, Accuracy of 0.92 and 0.93 and R2 of 0.92 and 0.93, for the training and validation models, respectively. These models outperformed the models utilized on the MK-mixed concrete found in the literature, therefore are the better decisive modes for the prediction of the splitting strength (Fsp) of the studied MK-mixed concrete with 204 mix data entries. Conversely, the NB and SGD produced unacceptable model performances, however, this is true for the modeled database collected for the MK-mixed Fsp. The RSM model also produced superior performance with an accuracy of over 95% and adequate precision of more than 27. Overall, the KNN, SVM, CN2 and RSM have shown to possess the potential to predict the MK-mixed Fsp for structural concrete designs and production.

Impact of downstream obstructions on ogee weir efficiency: a regression analysis

ABSTRACT This study delves into the impact of downstream obstruction angles on the discharge coefficient (Cd) over ogee weirs within open channel flows, a critical factor for accurate flow rate predictions in hydraulic engineering. Employing a series of detailed laboratory experiments the influence of various obstruction angles on Cd was scrutinized applying a suite of regression analysis to develop predictive models. The analysis was enriched by considering hydraulic parameters such as flow rate, water level, and weir geometry. Despite the established importance of Cd in hydraulic designs the nuanced effects of downstream obstructions have received limited attention highlighting a critical research gap. The findings highlight a strong correlation between obstruction angles and Cd, with developed regression models demonstrating notable predictive strength. Remarkably the models exhibited varying levels of accuracy, with the Random Forest regressor achieving an exceptionally low root mean square error (RMSE) of 0.005, indicating superior predictive performance. Conversely, traditional models like Decision tree and XG BOOST reflected higher RMSE values of 0.60, suggesting less predictive accuracy in this context. LASSO, Bayesian Ridge, and OMP regressors stood out with an RMSE of zero, denoting perfect predictions under the study's specific conditions.

Resolved Simulation for the Prediction of Classification in Decanter Centrifuges

Solid–liquid separation plays a decisive role in various industrial applications particularly in the treatment and purification of suspensions. Solid bowl centrifuges, such as the decanter centrifuge, are commonly employed in these processes as they operate continuously and enable high throughputs with short processing times. However, predicting the separation performance of solid bowl centrifuges proves to be challenging due to dynamic phenomena within the apparatus, such as particle settling, sediment build-up, consolidation and sediment transport. In practice, design considerations and the dimensioning of the apparatus rely on analytical models and the manufacturer’s expertise. Computational Fluid Dynamics (CFD) offers a way to deepen our understanding of these devices by allowing detailed examination of flow phenomena and their influence on the separation processes. This study utilizes the open-source software OpenFOAM to simulate multiphase flow in a laboratory-scale decanter centrifuge, solving individual transport equations for each particle size class. The basis is the characterization of the material through targeted laboratory experiments to derive material functions that describe the hindered settling and the sediment consolidation. Furthermore, experiments on a laboratory decanter served as validation. The results demonstrate the solver’s capability to replicate clarification and classification within the apparatus. Furthermore, the solver supports the definition of geometries tailored to specific separation tasks. This research demonstrates the potential of CFD for a better understanding of complex centrifuge processes and for optimizing their design to improve performance.

Experimental evaluation of dynamic geotechnical parameters of tailings

The paper is focused on the testing of material from the "Lyulyakovitsa" tailings dam situated in proximity to the town of Panagyurishte in Bulgaria. The primary objective of this study is to investigate various laboratory techniques aimed at determining essential dynamic characteristics of the studied material. This research is conducted with the goal of subsequently assessing the seismic response of the existing tailings dam. In the context of performing an equivalent linear analysis, a widely used approach in geotechnical earthquake engineering, several crucial relationships and parameters come into play. These include the material's stiffness degradation, the damping ratio, and the small-strain stiffness, expressed through the shear wave velocity. The paper describes analysis of three experiments carried out in the geotechnical laboratory "Komaba" at the University of Tokyo. These experiments introduce undrained cyclic triaxial tests conducted under identical relative density (95%) of the tailings and executed at 50 kPa, 80 kPa, and 100 kPa effective confining stress, specifically, respectively. Additionally, two distinct testing methods were employed to measure the shear wave velocity in the specimens. The findings align with certain established directions in the existing literature for characterizing the dynamic properties of granular soils. Simultaneously, they underscore the practicality of the laboratory experiments adopted for acquiring a comprehensive set of relationships and parameters.

Biocontrol potential of some bacterial and fungal isolates against the terrestrial snail, Monacha obstructa, evaluating their laboratory and field efficiency

BackgroundThe land snail Monacha obstructa, commonly known as the glassy clover snail, poses a significant threat to crops, causing substantial damage in agriculture and horticulture. It particularly thrives in regions of Egypt, where it can reproduce rapidly, leading to substantial population increases and consequent damage. This study aimed to perform laboratory experiments and field trials to assess the effectiveness of bacterial (Bacillus thuringiensis) and fungal (Metarhizium anisopliae and Trichoderma harzianum) isolates, as well as methomyl, a carbamate compound approved by the Ministry of Agriculture in Egypt against the terrestrial snails. Various methods including contact and leaf dipping as well as baiting techniques were applied under both laboratory and field conditions, using spray and baiting techniques.ResultsBacillus thuringiensis (Bt) and M. anisopliae isolates showed the most effective results outcomes in comparison with methomyl against M. obstructa. Out of all the application approaches tested, the residual film (contact) technique of these microorganisms proved to be the most potent, with LC50 values of 6.49 × 106 cells/ml Bt (after 14 days), 1.24 × 108 and 1.49 × 108 spores/ml (M. anisopliae, T. harzianum, respectively), after 21 days and 620 ppm, for methomyl after 7 days of treatments. Besides, the findings demonstrated that Bt exhibited the highest success rate in decreasing the number of snails in the field. It was also observed that pathological symptoms increased as the duration of exposure increased, and the snails ceased to feed and showed a noticeable decline in their activity. A slimy, almost tan-like substance coated the exterior of their shells for Bt, and part of the soft body came out of the shell for M. anisopliae. In the case of T. harzianum, fungus hypha growth took on a white color formed inside the shell, and in addition, a black substance formed on the mouth of the shell.ConclusionsThe gathered data revealed that Bt and M. anisopliae effectively combatted the terrestrial snail, making them viable options in integrated pest control as substitutes for pesticides.

Numerical investigation for water flow in an irregular channel using Saint–Venant equations

Given recent flood events in Indonesia, understanding the hydraulic dynamics in open channels, mirroring real-world drainage and river scenarios, has become paramount. To address this, our research employs a numerical model to simulate water flow in both regular and irregular open channels. Specifically, we utilize the Saint–Venant Equations to explore fluid flow evolution in irregular channels. This model is solved numerically using a staggered finite volume method. We complement our research with laboratory experiments and validate our numerical model against the data collected. Furthermore, we cross-reference our numerical results with those from HEC-RAS to examine the robustness and accuracy of our model in predicting water levels and velocities under varying conditions. To deepen our understanding, we conduct sensitivity analyses that offer valuable insights into the core factors influencing water levels and velocity. This knowledge provides a foundation for practitioners to normalize rivers.

Abnormal eyes and spine development in zebrafish (Danio rerio) embryos and larvae induced by triphenyltin

Triphenyltin (TPT) is widely used in crop pest control and ship antifouling coatings, which leads to its entry into aquatic environment and poses a threat to aquatic organisms. However, the effects of TPT on the early life stages of wild fish in natural water environments remains unclear. The aim of this study was to assess the toxic effects of TPT on the early life stages of fish under two different environments: field investigation and laboratory experiment. The occurrence of deformities in wild fish embryos and larvae in the Three Gorges Reservoir (TGR) and the developmental toxicity of TPT at different concentrations (0, 0.15, 1.5 and 15 μg Sn/L) to zebrafish embryos and larvae were observed. The results showed that TPT content was higher in wild larvae, reaching 27.21 ng Sn/g w, and the malformation of wild fish larvae mainly occurred in the eyes and spine under natural water environment. Controlled experiment exposure of zebrafish larvae to TPT also resulted in eye and spinal deformities. Gene expression analysis showed that compared with the control group, the expression levels of genes related to eye development (sox2, otx2, stra6 and rx1) and spine development (sox9a and bmp2b) were significantly up-regulated in the 15 μg Sn/L exposure group, which may be the main cause of eye and spine deformity in the early development stage of fish. In addition, the molecular docking results further elucidate that the strong hydrophobic and electrostatic interactions between TPT and protein residues are the main mechanism of TPT induced abnormal gene expression. Based on these results, it can be inferred that TPT is one of the teratogenic factors of abnormal eye and spine development in the early life stage of fish in the TGR. These findings have important implications for understanding the toxicity of TPT on fish.

Cryogenic gastronomy at The Restaurant at the End of the Universe – exploring interstellar serine synthesis from α-glycyl radical and other ingredients

Amino acids are essential for Earth-like life and are hypothesised to have originated in interstellar space, potentially being transported to Earth via meteorite impacts. Detecting amino acids in interstellar environments and understanding their formation mechanisms through laboratory experiments are crucial for supporting this hypothesis and unravelling the origins of life. In this study, the formation of serine ( NH 2 CH ( CH 2 OH ) COOH ) from α-glycyl ( NH 2 C ⋅ HCOOH ) and hydroxymethyl ( ⋅ CH 2 OH ) radicals was investigated using quantum chemical computations. It was found that the anticipated recombination reaction, along with analogous formation pathways of other natural amino acids, is accompanied by competing reactions yielding alternative products, potentially diminishing serine formation. Alternative interstellar formation pathways for serine are proposed, which could be experimentally tested by future laboratory studies.

Adapting Methods For Bed Level Assessment In And Around Submerged Vegetation

Coastal vegetation has the capacity to reduce flow and orbital velocities near the bed and stabilize the sediment with its root network. As a result it has an effect on sediment dynamics which gains increasing attention as ecosystem service in coastal protection. To quantify and predict this ecosystem service, laboratory experiments with live or artificial vegetation are often conducted. During these experiments the assessment of bed level change is challenged by the presence of the vegetation. Standard optical and acoustic measurement techniques cannot obtain data below vegetation canopies. Especially for submerged flexible vegetation like seagrass, this challenge is aggravated for airborne methods that require flume drainage (e.g. terrestrial laser scanning) (Follett and Nepf, 2012). Flexible blades will spread on the ground during drainage, potentially covering meadow edges and thus excluding areas of interest from the bed level analysis. Moreover, live aquatic vegetation may be stressed by air exposure, if the facility is drained for bed level measurements. This potentially leads to different, non-natural behaviour in consecutive experiments. And finally, draining and refilling the facility is time consuming, especially as it needs to be done very carefully as not to disturb any generated bedforms. This time aspect hampers the collection of time series and thus the assessment of the development of bed level changes with airborne methods. Underwater technology like sonar and echo sounder avoid shading of areas by spread-out vegetation, but are equally not capable of obtaining data below vegetation canopies. Moreover, instruments that can obtain spatially resolved data underwater often require a minimum water depth which may exceed the water depth relevant for experiments with vegetation. In intertidal areas (e.g. salt marshes) the challenge of obtaining bed level data below vegetation canopies is overcome by the use of a sediment-erosion-bar (SEB) (Cahoon et al., 2002). For this method a horizontal bar is installed at a fixed height above the ground and the distance between this bar and the ground is measured at defined locations along the bar and set time intervals to obtain information on the bed level change. SEBs have successfully been adapted to laboratory settings in the past (Spencer et al., 2016), but still required flume drainage. We applied this method in an undrained flume to assess sediment dynamics in and around an artificial seagrass meadow. Additionally, we tested underwater photogrammetry to obtain 3D-spatial information (e.g., 3D models) on bed level and bedforms at and near the vegetation edges. Photogrammetry has been successfully applied to obtain bedform information in the presence of seagrass stands, but to date still required the drainage of the facility (Meysick et al., 2022).

Effects of liquid viscosity and air injection rate on air invasion in a highly compacted granular material

Using laboratory experiments on a network scale together with numerical simulations on a granular scale, we investigate the displacement process as air invades a highly compacted granular material. Experiments in a vertically placed Hell-Shaw cell reveal a non-monotonic behavior of branching formation as air injection rate Q increases from 0.1 to 50 ml min–1 when the liquid viscosity is less than 22.5 mPa s. In the low-injection-rate region where Q < 1 ml min–1, fractures grow in random directions, and the number of branches increases as the air injection rate decreases. However, after the transition to the high-injection-rate region where Q≥ 1 ml min–1, the number of branches increases with increasing air injection rate. At a given air injection rate, increasing the liquid viscosity from 1.01 to 219 mPa s leads to an increasingly concentrated air flow. The numerical simulations exhibit good agreement with the experimental results. More importantly, they shed light on the physics underlying the growth of the fractures by capturing the distribution of the magnitude of velocity, as well as computing the inter-grain force chains in the granular material. The simulations suggest that a high liquid viscosity concentrates the velocity field and force chains and reduces the speeds and inter-grain forces of the grains adjacent to fractures, while a higher air injection rate increases the grain speeds and inter-grain forces. In addition, the distribution of the forces chains behaviors non-monotonically as the air injection rate decreases, which explains the non-monotonic behavior of branching formation observed in the experiments.

Salinity effects on germination of Portulaca oleracea L.: A multipurpose halophyte from arid rangelands

Salt resistance studies have, unfortunately, mainly been focused on conventional crops, with very few studies being conducted on the potential of available halophytes as new crops in the future. Portulaca oleracea L. has been listed as one of the most used medicinal plants by the World Health Organization as an edible halophyte. It is a fast-growing herbaceous annual with high nutritional relevance. The present work was designed to determine the effect of six soluble salts (NaCl, Na2SO4, KCl, CaCl2, CaCO3, and MgCl2) on germination of P. oleracea seeds. The effect of salinity was tested on final germination percentage (FGP%), and germination tolerance index (GTI%) using five concentrations (0, 200, 300, 400, and 600mM) of each salt. In addition, laboratory experiments were conducted to assess the effects of salinity on germination recovery from high saline conditions (600mM). Salinity level and salt composition significantly influenced germination attributes. P. oleracea seeds were non-dormant, exhibited approximately 100% germination in distilled water. Both FGP and GTI gradually decreased with increasing salinity. This study showed that seeds of P. oleracea can germinate under 300mM in all tested salts. The salts causing germination inhibition exhibited specificity, with an increasing trend observed in the following sequence: MgCl2 > Na2SO4 > NaCl > KCl > CaCl2 > CaCO3. Transferring ungerminated seeds from 600mM to distilled water recovered their germination ability. Based on these results, we can conclude that P. oleracea is a high salt-tolerant species that can tolerate a variety of salts found in soil. Therefore, P. oleracea may be considered a promising species for improving ecological balance in saline soils.

Exploring the demand for elective egg freezing: A laboratory experiment

We conducted a proof-of-concept analysis to demonstrate that government funding decisions can be studied within a lab experiment: We explore the effects of government funding levels, information level, and various participant characteristics on the demand for elective egg freezing (EEF) and in vitro fertilization (IVF), two types of fertility treatment, and determine price and income elasticities of demand within an incentive-compatible experiment.We recruited 217 female participants without children aged 20-29 years. Participants were assigned to one of three between-subjects experimental treatments that varied income endowment and information provided. Additionally, the experiment consisted of 3 within-subjects conditions corresponding to different levels of government funding for IVF and EEF with 2 decision periods (‘planning period’ and ‘family-formation period’) and participants had to indicate their treatment choice aiming to achieve a live birth.The demand for EEF and IVF were shown to be price-inelastic. We found that the increase in the price for EEF and IVF through restrictions in government funding significantly reduced demand for such treatments. However, demand did not significantly change with income level, suggesting a high value associated with fertility treatment.Overall, our study shows that government funding decisions for medical interventions can be explored within an experimental setting.

The pressure drop of fibrous surface filters for gas Filtration: Modeling and experimental studies

Surface filters are extensively utilized for the control of particulate matter and air pollution, and predicting the pressure drop can offer theoretical guidance in the selection of operational parameters for fibrous surface filters. However, there is presently a dearth of efficient and user-friendly methods for predicting the pressure drop. This paper focuses on the accurate and convenient prediction of the pressure drop of fibrous surface filters for gas filtration. Firstly, an analytical model for pressure drop, including the blocked fiber layer and the dust cake, was developed by considering the characteristics of the filter media, dust properties, and loading conditions. The model was validated through laboratory experiments, and the relative error between the model values and experimental data remains within a 15% error. Furthermore, based on the model, the quantitative analysis of the relationship between the pressure drop of the fiber layer and the pressure drop of the dust cake, and the filtration parameter importance were conducted. The influence of filtration parameters on the pressure drop follows the order of filtration velocity, dust concentration, and dust particle size, which provides guidance for choosing the gas filtration operating conditions in the efficient and low-resistance operation of surface filters. Additionally, the model was validated through field test data collected with large-scale cartridge filters in bulk grain loading. The predicted values fit well with the field test results. Overall, this study provides a promising tool for predicting the pressure drop of fibrous surface filters.

Production of polyhydroxybutyrate from industrial flue gas by microbial electrosynthesis

The aim of this work was to produce the biopolymer polyhydroxybutyrate (PHB) from industrial flue gas as CO2 source and electrolysis originating hydrogen via microbial electrosynthesis. Besides the laboratory experiments, the experiments were carried out under industrial conditions directly on-site in a cogeneration plant. We were able to demonstrate that the use of flue gas as a CO2 source has no detectable negative effect on bacterial growth and PHB production in comparison to a pure gas mixture. In an electrochemical H-cell 333 ± 44 mg L−1 PHB were obtained, which corresponds to a PHB content of 43 ± 3 % of the cell dry weight. By using flue gas for the production of the biopolymer PHB, not only CO2 emissions are reduced, but also possible environmental pollution from non-biodegradable plastics. To the best of our knowledge, this is the first time that the production of PHB from flue gas has been demonstrated using Cupriavidus necator.

Fate of synthetic chemicals in the agronomic insect pest Spodoptera littoralis: experimental feeding-contact assay and toxicokinetic model.

Insecticides prevent or reduce insect crop damage, maintaining crop quality and quantity. Physiological traits, such as an insect's feeding behavior, influence the way insecticides are absorbed and processed in the body (toxicokinetics), which can be exploited to improve species selectivity. To fully understand the uptake of insecticides, it is essential to study their total uptake and toxicokinetics independent of their toxic effects on insects. We studied the toxicokinetics (TK) of insecticidally inactive test compounds incorporating agro-like structural motifs in larvae of the Egyptian cotton leafworm (Spodoptera littoralis,Lepidoptera),and their distribution across all biological matrices, using laboratory experiments and modeling. We measured Spodoptera larval behavior and temporal changes of whole-body concentrations of test compounds during feeding on treated soybean leaf disks and throughout a subsequent depuration period. Differences in the distribution of the total quantities of compounds were found between the biological matrices leaf, larva, and feces. Rate constants for uptake and elimination of test compounds were derived by calibrating a toxicokinetic model to the whole-body concentrations. Uptake and elimination rate constants depended on the physicochemical properties of the test compounds. Increasing hydrophobicity increased the bioaccumulation potential of test compounds. Incomplete quantities in larval matrices indicated that some compounds may undergo biotransformation. As fecal excretion was a major elimination pathway, the variable time of release and number of feces pellets led to a high variability in the body burden. We provide quantitative models to predict the toxicokinetics and bioaccumulation potential of inactive insecticide analogs (parent compounds) in Spodoptera.

Life is too short to be small: An experiment on mortality salience and prosocial behavior

We study how mortality salience influences people's time preference and prosocial behavior in a laboratory experiment. We made mortality salient through priming subjects in the treatment group with grid tasks, and studied its impact on altruistic giving in an Andreoni-Miller dictator game. We found that the priming made subjects think bigger, and become more concerned with the overall social welfare, though it did not necessarily make them care more about their opponents' well-being per se. Subjects in the treatment group became more altruistic only when the price of giving is low. We built a two-period model to explain the mechanism of the findings. Our model showed that the priming altered altruistic giving through changing the subjects' time preference and social preference parameters. Finally, we strengthened our findings by showing that the priming didn't change subjects' mood.

Influence of Combustion Temperature and Composition of Organic Soil Horizons on the PAH Content (Laboratory Experiment)

Influence of Combustion Temperature and Composition of Organic Soil Horizons on the PAH Content (Laboratory Experiment)

Coal-derived conductive pavement for winter de-icing: prototype, modeling, and simulation

Existing pavement de-icing methods result in high installation and maintenance costs, traffic delays, excessive weariness and corrosion, and negative environmental and safety impacts. To overcome these challenges, this paper presents an innovative pathway to design and construct smart self-heating pavements using a low-cost coal-char bearing asphalt material. The conductive asphalt incorporates coal char, i.e., a key byproduct of the coal pyrolysis process, into the Stone Mastic Asphalt (SMA) mixture. This asphalt containing coal-derived solid carbon exhibits highly tailorable electrical conductivity, satisfactory mechanical and thermophysical properties, and superior cost-efficiency as compared to other conductive pavement materials. The de-icing performance was also demonstrated by laboratory experiments on a bench-scale prototype. Furthermore, an efficient thermal network model was developed and validated by experiments to investigate the transient thermal behavior and energy performance of the Ohmic heating pavement system. The whole-year energy simulation case studies were conducted on a bridge pavement with an annual energy use of 24.6–––1444.8 kWh/m2, showcasing its potential in field applications across cool humid, cold humid, and subarctic/arctic climate zones

The competition of heavy metals between hyporheic sediments and microplastics of driving factors in the Beiluo River Basin

Both sediments and microplastics (MPs) are medias of heavy metals (HMs) in river ecosystems. This study investigated HMs (Mn, Cr, V, As, Cu, Co, Cd, Pb, and Ni) concentration and driving factors for competitive enrichment between hyporheic sediments versus MPs. The medias basic characteristics indicated that the sediments were mostly sand and rich in Fe2O3; three polymer types were identified, with blue, fragment, less than 500μm being the main types of MPs. The results have shown that the average content of extracted HMs in MPs was much higher than that of the same metals accumulated in sediments. HMs in sediments and MPs reached heavily polluted at some points, among which As and Cd were ecological risks. Electrostatic adsorption and surface complexation, and biofilm-mediated and organic matter complexation were the interaction mechanism of HMs with sediments and MPs. Further, the driving factors affecting the distribution of HMs in the two carriers were analyzed by multivariate statistical analysis. The results demonstrated that carrier characteristics, hydrochemical factors, and the inherent metal load of MPs were the main causes of the high HMs content. These findings improved our understanding of HMs fate and environmental risks across multiple medias. Environmental ImplicationOwing to large specific surface area and hydrophobicity, microplastics adsorb heavy metals (HMs) from the surrounding environment, aggravating potential ecological hazards and posing a threat to aquatic organisms. Many laboratory experiments have confirmed the compound effect of the two, but the attribution of HMs in natural rivers under the influence of multiple factors remains to be studied.This study investigated the distribution of HMs concentrations in different media, assessed HMs pollution in sediments and microplastics, and explained the drivers of uneven HMs concentrations. The finding provides new insights for further understanding of the fate of HMs in ecosystems.