High Loading Rates Research Articles

Highly Aging‐Resistant Polybutadiene Rubber Doped With High‐Loading Antioxidant‐Loaded Titanium Carbide

ABSTRACTThe loading of antioxidants onto inorganic fillers is a vital method for preventing the migration of rubber antioxidants. However, the loading rate is not ideal, which has been a persistent problem for scholars in this field. In this work, the mussel‐based strategy was used to coat titanium carbide (Ti3C2) surfaces with polydopamine (PDA). The amino group on the antioxidant 4‐aminodiphenylamine (RT) is opened with the epoxy group on the silane coupling agent KH560, while the phenol hydroxyl group of PDA condenses with the silanol group on KH560 to prepare titanium carbide‐supported antioxidant molecules (Ti3C2‐RT). The layered Ti3C2 dispersed in the matrix material not only effectively prevents oxygen from entering, but also provides a large specific surface area for the supported antioxidant. At the same time, the introduction of high‐functionality polyamines and silane coupling agents creates conditions for the preparation of inorganic fillers with high loading rates of antioxidants. The loading rate of Ti3C2‐RT was evaluated by TGA, and the mass fraction of antioxidant RT on Ti3C2‐RT was approximately 16.5%, which means that it has the highest loading rate in the field of inorganic fillers loaded with antioxidants. In addition, the mechanical properties of polybutadiene rubber before and after aging were also studied. The test results show that the new antioxidant Ti3C2‐RT has good anti‐aging effect and can effectively prevent antioxidant precipitation. Therefore, compared to organic antioxidants, the supported antioxidant Ti3C2‐RT has a longer ability to scavenge free radicals, resulting in a longer service life of rubber products.

Microbial Nitrogen Removal in South San Francisco Bay: Does It Play a Role in Eutrophication Resistance?

The ecosystem response to anthropogenic nitrogen (N) loading in estuarine systems is determined by hydrodynamics, biogeochemical transformation rates, and other system-specific characteristics. Historically, San Francisco (SF) Bay has been an outlier from other estuaries with an unusual resistance to eutrophication, despite having extremely high rates of nitrogen loading. Recent increases in phytoplankton biomass and an unprecedented harmful algal bloom, however, have increased the urgency to understand rates and drivers of nitrogen removal in the system. To assess benthic N cycling rates, we conducted seasonal measurements across nine sites in South and Lower South SF Bay, the two sub-embayments with the highest rates of area-normalized N loading, to determine the rates and potential drivers of denitrification and dissimilatory nitrate reduction to ammonium (DNRA). Denitrification rates averaged 60.6 ± 8.1 µmol m−2 h−1 and were primarily coupled to nitrification. Denitrification rates were positively correlated with DNRA rates and % clay. DNRA rates ranged from 0 to 20 µmol m−2 h−1 and on an annual basis averaged ~ 10% of total benthic nitrate reduction, with a negative correlation to % clay content in the surface sediment. The measured denitrification rates account for the removal of, on average, 14% of N loaded annually to South SF Bay, leaving a sizeable portion for alternate fates (e.g., recycling, export, or burial) and potential for substantial temporal and spatial variability (1–79%). This identifies the relative importance of sediment denitrification in ecosystems characterized by high nutrients and low productivity.

Enhanced prediction of partial nitrification-anammox process in wastewater treatment by developing an attention-based deep learning network.

In the process of partial nitrification and anaerobic ammonia oxidation (anammox) for nitrogen removal, the process offers simple metabolic pathways, low operating costs, and high nitrogenous loading rates. However, since the partial nitrification-anammox (PN-anammox) process combines partial nitrification and anammox reactions within the same reactor, strict control of dissolved oxygen (DO) is essential. Additionally, assessing treatment performance through chemical measurement involves time lag, making it challenging to recover the biological process when issue arise, especially in the PN-anammox process, where strict DO control and the sensitivity of anammox bacteria to conditions and substrates demand timely intervention. Therefore, modelling for PN-anammox process is of great significance. Because of traditional modelling methods have limitations in this process, in this study, deep learning networks were applied to model and predict the process by constructing a dataset based on long-term experiments. Specifically, Long Short-Term Memory Network (LSTM) and Densely Connected Convolutional Network (DenseNet) were employed, and an enhanced Attention-based DenseNet (AttentionNet) was developed to further improve the prediction performance. These networks were utilized for long-term continuous PN-anammox reactors for nitrogen removal in low-strength wastewater. The results demonstrated that both DenseNet and the proposed AttentionNet effectively modeled the PN-anammox processes, even under conditions of unstable influent quality and relatively poor treatment performance. The mean relative error (MRE) for DenseNet was under 15%, while AttentionNet achieved an MRE of approximately 10% or less, highlighting the superior performance of the Attention layer. These findings were further validated by Bland-Altman analysis. Additionally, further analysis of AttentionNet showed that predictions for pH, nitrite nitrogen, and total nitrogen in the effluent were more accurate than those for other output parameters.

Tin(IV)Porphyrin-Based Porous Coordination Polymers as Efficient Visible Light Photocatalyst for Wastewater Remediation.

Two porphyrin-based polymeric frameworks, SnP-BTC and SnP-BTB, as visible light photocatalysts for wastewater remediation were prepared by the solvothermal reaction of trans-dihydroxo-[5,15,10,20-tetrakis(phenyl)porphyrinato]tin(IV) (SnP) with 1,3,5-benzenetricarboxylic acid (H3BTC) and 1,3,5-tris(4-carboxyphenyl)benzene (H3BTB), respectively. The strong bond between the carboxylic acid group of H3BTC and H3BTB with the axial hydroxyl moiety of SnP leads to the formation of highly stable polymeric architectures. Incorporating the carboxylic acid group onto the surface of SnP changes the conformational frameworks as well as produces rigid structural transformation that includes permanent porosity, good thermodynamic stability, interesting morphology, and excellent photocatalytic degradation activity against AM dye and TC antibiotic under visible light irradiation. The photocatalytic degradation activities of AM dye were found to be 95% by SnP-BTB and 87% by SnP-BTC within 80 min. Within 60 min of visible light exposure, the photocatalytic degradation activities of TC antibiotic were found to be 70% by SnP-BTB and 60% by SnP-BTC. The enhanced catalytic photodegradation performances of SnP-BTB and SnP-BTC were attributed to the synergistic effect between SnP and carboxylic acid groups. The carboxylic acid connectors strongly resist the separation of SnP from the surface of SnP-BTB and SnP-BTC during the photodegradation experiments. Therefore, the high degradation rate and low catalyst loading make SnP-BTB or SnP-BTC more efficient than other reported catalysts. Thus, the present investigations on the porphyrin-based photocatalysts hold great promise in tackling the treatment of dyeing wastewater.

Anti-inflammatory supramolecular hydrogel loaded chicoric acid based on graphene oxide modified hyaluronic acid and polyethylene glycol for rheumatoid arthritis treatment.

Chicoric acid (CA) as one of Chinese medicines had anti-inflammatory, less gastrointestinal irritation, less drug-resistance and low cost properties compared with chemical synthesized drug and biologics for rheumatoid arthritis (RA) treatment. To make CA preciously and effectly RA therapy, we firstly developed a supramolecular hydrogel (GHCAP) comprising β-cyclodextrin and graphene oxide (GO) modified hyaluronic acid (CD-HA-GO) as the "host" polymer and adamantane-modified four-arm polyethylene glycol (PEG-AD) as the "guest" polymer, and then the CA was loaded into the supramolecular hydrogel (DGHCAP). The results showed that DGHCAP exhibited injectable, high modulus, high CA loading rate (43.38 %) and slow CA releasing ratio (releasing 80 % in 80 h) compared with those of the supramolecular hydrogel without GO (DHCAP). Moreover, the DGHCAP demonstrated excellent compatibility and effect anti-inflammatory (down regulated proinflammatory cytokines such as IL-1β, IL-6, TNF-α and iNOs) in both in vitro and in vivo assays. The supramolecular hydrogels loaded Chinese medicine could provide another method to treat RA in clinical.

High-rate nitrogen loading accelerates organic phosphorus loss through enzymatic and non-enzymatic processes in a semi-arid grassland

Semi-arid grasslands suffer from increased nitrogen (N) loading, which affects phosphorus (P) cycling. Phosphorus is essential but limited for all living organisms. Organic P (Po) is crucial for P supply in grasslands response to N loading, but its transformation process remains unclear. To elucidate P cycling, we evaluated P fractions, phosphatase activities, and their coding genes (pho genes phoD, phoX, and phoC) at both DNA and RNA levels in response to a nitrogen loading gradient. The results showed that the total P and Po contents significantly decreased with increasing N loading rates. In contrast, plant and litter biomass P exhibited an opposite trend but were insufficient to offset soil P loss. Unexpectedly, neither the phosphatase activities nor microbial biomass increased with increasing N loading rates, although the DNA abundance of pho genes responded positively to N enrichment. A partial correlation network indicated that N loading rates decreased Po levels through phosphatase activities, which were significantly associated with soil pH and the RNA abundance of pho genes. Moreover, non-enzymatic mineralization may be enhanced in Po cycling in semi-arid grasslands undergoing high N loading, especially following the initial stage of enzymatic mineralization. Although the activity of phosphatases did not continue to rise with increased N loading, the strategy for addressing N-induced P limitation through overconsumption of Po via non-enzymatic processes would accelerate the degradation of the ecosystem in the future.

Studies on Bio-denitrification of Wastewater Using Immobilized GAC in Draft Tube Spouted Bed Reactor

Introduction: The draft tube-spouted bed bioreactor with GAC particles immobilized with Pseudomonas syringae is being evaluated to study the effect of suspended biomass and biofilm thickness on the rate of denitrification. Though the biofilm thickness is not directly controlled in wastewater treatment by the diffusion limitation and consequent substrate penetration in the biofilm, biofilm thickness will probably have a significant impact on bacteriological activity. Materials and Methods: The reactor studies were accomplished to study the result of dilution rate on attached biomass, suspended biomass, and biofilm thickness with nitrate reduction under steady-state conditions. A spouted bed reactor with the growth media prepared was used to study the bio-denitrification using Pseudomonas syringae. Results: The study of the attached biomass on nitrate reduction indicated that, as the attached biomass increased from 0.35 g/g to 0.54 g/g at a 0.166/h dilution rate, the nitrate reduction percentage decreased from 98.18% to 88.2%. During the study, it was observed that the biomass and biofilm thickness increased and decreased, respectively, with a rise in influent nitrate concentration and dilution rate. The rise in dilution rate as well as influent nitrate concentration throughout the study increased the rate of suspended biomass. Conclusion: The nitrate reduction rate was high with higher rates of loading in a draft tube spouted bed bioreactor, due to well-organized recirculation of the solids inside the reactor. The formation of biofilm thickness on solids is a significant character as it increases the nitrate reduction rate to meet the effluent standards

Deciphering the Antimicrobial and Antibiofilm Efficiency of Thyme Essential Oil Encapsulated Zeolitic Imidazole Framework-8 Against Foodborne Pathogens.

Food Packaging using antibacterial substances plays a vital role in food industry in controlling contamination caused by food borne pathogens. Stability and pH dependent degradation characteristics of zeolitic imidazole framework-8 (ZIF-8) makes its suitable candidate for biomedical applications. The present study focuses on thyme essential oil (TEO) encapsulated in ZIF-8 to achieve a synergistic antibacterial effect and prolonged drug release, aiming to extend the shelf life of food products. Optical, structural and surface characterizations of TEO encapsulated within ZIF-8 (ZIF-8@TEO) reveals successful incorporation of TEO into ZIF-8 nanoparticles. High drug loading and pH dependent release rate with higher release rate at acidic condition (75%) makes ZIF-8 a promising drug delivery system. ZIF-8@TEO exhibited potent antimicrobial against Staphylococcus aureus, Bacillus subtilius and Pseudomonas aeruginosa, also attenuated the biofilm forming ability of these food borne pathogens. In vitro and in vivo toxicity studies reveal the non-hemolytic and non-toxic nature indicating its biocompatible nature. The results of the study reveal that ZIF-8@TEO nanoconjugate can be used for the development of novel antibacterial nanocomposite-based films for food packaging applications.

The tensile behaviour of paper under high loading rates

AbstractThis work deals with the strain-rate dependent characterization of paper under uniaxial tension at high strain-rates. Experiments were performed involving a Split Hopkinson bar for high strain-rate testing, comparing the results with conventional quasi-static tests. Tests were conducted in a strain-rate range between 0.0083 and 212 s−1, which is equivalent to testing velocities between 0.0003 and roughly 13.6 m/s. For the first time the change in tensile behaviour of paper is comprehensively characterized and modelled, using the Cowper-Symonds model for strain-rate hardening. The experimental tests showed that the tensile strength as well as the initial stiffness were gradually increasing with increasing strain-rate. The increase in tensile strength between the lowest and the highest strain-rate was 58% on average whereas the mean increase in stiffness between these two strain-rates was almost 115%. Regarding the fracture strain, it was observed that it significantly decreases with increasing strain-rate. While the average fracture strain of the quasi-static tests was at roughly 6% it was close to 3% for the dynamic tests. In case of the Split Hopkinson bar tests, high-speed videos of the samples were made to determine their elongation via target tracking and digital image correlation (DIC). We found that strain localization, which is a highly relevant mechanism for quasi-static tensile failure, is likely related to short term plastic creep of the material as strain localization nearly entirely disappears at high loading rates of paper.

Ideal Bi-Based Hybrid Anode Material for Ultrafast Charging of Sodium-Ion Batteries at Extremely Low Temperatures

HighlightsMetallic nanoparticles with excellent size controllability and high loading rate are obtained via ultrafast high temperature shock method.The Bi/CNRs-15 electrode exhibits an unprecedented rate performance (237.9 mAh g−1 at 2 A g−1) at − 60 °C, while the energy density of the full cell can reach to 181.9 Wh kg−1 at − 40 °C.A novel strategy of high-rate activation is proposed to obtain high capacity and superior stability at low temperature by creating new active sites for interfacial reaction.

In–Li Counter Electrodes in Solid‐State Batteries – A Comparative Approach on Kinetics, Microstructure, and Chemomechanics

AbstractA key challenge for solid‐state batteries is the fabrication of high‐capacity cathodes with high area loading and good rate performance. To reliably quantify the performance of high‐capacity cathodes, electrochemically stable, and high‐rate counter electrodes are essential. Otherwise, a three‐electrode setup is required. In–Li alloy electrodes are used for years in a kind of standard approach, since these seem to offer stable operation. In this comparative study, seven preparation methods for In–Li electrodes are examined, determining their suitability for cathode testing. The microstructure of a planar (i.e., foil) and a particle‐based (i.e., composite) anode configuration is analyzed in more detail. Their rate‐dependent electrode performance as well as electrochemical and chemomechanical reversibility in full‐cell configuration are analyzed. The combined results demonstrate the limitations of In–Li electrodes for high‐capacity testing, especially at high rates, while confirming their suitability for simple lab‐scale testing. Preparation significantly influences the electrode microstructure and kinetics, consequently impacting the performance benchmarks of cathodes. These findings underscore both the challenges involved in applying In–Li counter electrodes and the resulting limited comparability of results from different laboratories.

Impact of Cognitive Tasks on Biomechanical Adjustments During Single-Leg Drop Landings in Individuals with Functional Ankle Instability

This study aimed to evaluate the biomechanics of single-leg drop landing in individuals with functional ankle instability (FAI) during cognitive tasks, contrasting these findings with those of healthy controls to provide insights for evidence-based rehabilitation strategies. Fifteen FAI participants, identified using clinical tools, were age- and activity-matched with controls. They performed drop landings with and without a cognitive task, and the data were analyzed using a 2 × 2 mixed ANOVA. At the initial ground contact (IC), the FAI group’s affected side showed a significantly smaller plantarflexion angle than the control group (p = 0.008). With cognitive tasks, this angle increased in the FAI group (p = 0.005). The FAI group also had larger knee flexion at contact (p = 0.002) and greater knee valgus at peak vertical ground reaction force (vGRF) (p = 0.027). They exhibited a higher peak vGRF, shorter time to peak vGRF (T-vGRF), and higher loading rate (LR) (all p < 0.05). No differences were found in other variables (p > 0.05). This study shows that FAI individuals make specific biomechanical adjustments under cognitive tasks, notably increased plantarflexion at IC, suggesting reactive compensations. Despite similar motor control to controls, this may reflect long-term adaptations rather than equal proficiency.

Smart Mesoporous Silica Nanoparticles Loading Curcumin Inhibit Liver Cancer.

Curcumin (CUR) as one of the natural edible pigments is approved by the World Health Organization due to its nontoxic and anticancer effect. However, the utility of CUR is restricted due to its low oral bioavailability. Nanoparticle drug delivery systems like mesoporous silica nanoparticles (MSNs) have been extensively used due to their high specific surface area, high loading rate, and ease of modification. This study developed lactobionic acid (LA)-modified carboxymethyl chitosan (CMCS)-coated MSNs to deliver CUR specifically targeting hepatocellular carcinoma. Among these nanoparticles, LA targets liver cancer cells. CMCS utilizes pH-responsive release of CUR. The LA-CMCS-MSN@CUR (MSN@CUR) were evaluated using several methods, including Fourier transform infrared spectroscopy, transmission electron microscopy, and zeta potential measurements. Liver cellular uptake of MSN@CUR depends on a specific LA receptor-mediated endocytosis mechanism. Additionally, MSN@CUR performed with a better antitumor effect than Cur in H22 orthotopic transplantation of liver cancer and H22 solid tumor mouse models. Treatment with MSN@CUR significantly reduced the protein of VEGF, p-PI3K, and AKT, increased the protein of caspases 3 and 8, ultimately inhibited tumor migration, and promoted apoptosis. This study provides a new path for delivery of natural active ingredients with excellent bioavailability in the antitumor field.

Arginine enhances activity of anammox consortia and process stability with increased nitrogen loading

Cross-feeding based on amino acids metabolism is an important strategy by which anammox bacteria and the co-existing heterotrophs facilitate their own growth and survival. Arginine is one of the necessary amino acids required for bacterial protein biosynthesis but whether adding arginine could benefit growth of anammox bacteria remains unknown. In this study, arginine was supplemented at dose of 5 mg·L−1 to promote the nitrogen removal performance of anammox bioreactors under varied loading rates. The results showed that nitrogen removal efficiency increased by 10.2 % under higher loading rates. Arginine addition substantially simulated the secretion of extracellular proteins and polysaccharides within anammox consortia as a strategy against unfavorable conditions. Canditatus Kuenenia dominated the anammox consortia and their 16S rRNA abundance and anammox-related functional genes were significantly increased by up to 0.42 times and 5.81 times, respectively. The findings of this study provided a feasible strategy to improve the performance of anammox reactors with arginine supplementation.

Advancing characterization of VOC diffusion in indoor fabrics: A dual-porosity modeling approach

Volatile organic compounds (VOCs) are major chemical pollutants in indoor air. Indoor fabrics, such as curtains, carpets, sofas, and clothes, strongly adsorb VOCs due to their high loading rates and large specific surface areas. The desorption of VOCs from these fabrics can act as a secondary source, worsening indoor air pollution and prolonging its effects. The diffusion coefficient is a key parameter that determines the source-sink properties of fabrics. In this study, the VOC diffusion characteristics in fabrics were investigated through microstructural examination, mass transfer analysis, and environmental chamber experiments. Yarn and fiber gaps were identified as dual mass transfer channels within the fabrics and were represented using two distinct fractal models. A dual-porosity medium (DPM) model, based on these fractal representations, was developed to predict the VOC diffusion coefficients in indoor fabrics and was validated via experiments under various environmental conditions and fabric-VOC combinations. The results highlight the significant impact of fabric structure and composition on VOC adsorption and emission dynamics. The validated DPM model provides a comprehensive approach to predicting VOC diffusion in fabrics, providing a more accurate method for assessing indoor air quality and fabric-mediated human exposure.

Refining the gut colonization Zophobas morio larvae model using an oral administration of multidrug-resistant Escherichia coli

BackgroundThe darkling beetle Zophobas morio can be implemented as an alternative in vivo model to study different intestinal colonization aspects. Recently, we showed that its larvae can be colonized by multidrug-resistant Escherichia coli strains administered via contaminated food (for 7 d) for a total experimental duration of 28 d. MethodIn the present work, we aimed to shorten the model to 14 d (T14) by administering the previously used CTX-M-15 extended-spectrum β-lactamase-producing ST131 E. coli strain Ec-4901.28 via a single oral administration (5 µL dose of 108 CFU/mL), using a blunt 26s-gauge needle connected to a 250 μL gastight syringe. Force-feeding was performed either without or with (larvae placed on ice for 10 min before injection) anaesthesia. In addition, phage-treated larvae were orally injected with 10 µL of INTESTI bacteriophage cocktail (∼105–6 PFU/mL) on d 4 (T4) and 7 (T7). ResultsGrowth curve analyses showed that, while larvae rapidly became colonized with Ec-4901.28 (T1, ∼106–7 CFU/mL), only those anaesthetized maintained a high bacterial load (∼102–3 vs. ∼105–6 CFU/mL) and survival rate (76% vs. 99%; P < 0.001) by T14. Moreover, bacteriophage administration to anaesthetized larvae significantly reduced the bacterial count of INTESTI-susceptible Ec-4901.28 at T14 (5.17 × 105 vs. 2.26 × 104, for non-treated and phage-treated larvae, respectively; P = 0.04). ConclusionsThe methodological refinements applied to establish the intestinal colonization model simplify the use of Z. morio larvae, facilitate prompt evaluation of novel decolonization approaches and reduce experiments involving vertebrate animals in accordance with the Replacement, Reduction and Refinement principles.

Enrichment of Methanothrix species via riboflavin-loaded granular activated carbon in anaerobic digestion of high-concentration brewery wastewater amidst continuous inoculation of Methanosarcina barkeri

Effective treatment of high-concentration brewery wastewater through anaerobic digestion (AD) has always been a challenging issue. Enhancing direct interspecies electron transfer (DIET) was demonstrated to increase methane production during AD under high organic loading rate (OLR). Herein, the feasibility of enhancing DIET with the addition of riboflavin-loaded granular activated carbon (RF-GAC) as well as co-addition with Methanosarcina barkeri (Rf-GAC+M.barkeri) was investigated (M.barkeri is well-known to be capable of DIET with electroactive bacteria). During the whole process, the Rf-GAC and the Rf-GAC+M.barkeri group both achieved average COD removal rates above 97 %, which was 14 % higher than that of the control. The average methane production in the Rf-GAC group and the Rf-GAC+M.barkeri group respectively reached 0.334 ± 0.02 L(stp)/g COD and 0.345 ± 0.02 L(stp)/g COD, 1.35 and 1.39 times higher than the 0.247 ± 0.03 L(stp)/g COD reached by the control. The control reactor deteriorated at an OLR of 12 kg COD/(m3·d), whereas the Rf-GAC and the Rf-GAC+M.barkeri group maintained stable as the OLR reached as high as 17.5 kg COD/(m3·d) and the volatile fatty acids concentration was consistently below 10 mM. The RF-GAC performed better than Rf-GAC+M.barkeri in enriching Methanothrix, whose relative abundance was 60.6 % in the former group. Metabolic pathway analysis revealed the addition of RF-GAC upregulated genes related to DIET in Methanothrix species, including hdrA and fpoD. Furthermore, Methanothrix remained the dominant archaea even continuously inoculating pure strains of M.barkeri during the entire operational period. Pure culture experiments proved that GAC inhibited M.barkeri growth. The results of this study can be optimized for practical application of AD treating high-concentration brewery wastewater.

Rate dependency and fragmentation response of phase field models with micro inertia and micro viscosity terms

We present elliptic, parabolic, and hyperbolic phase field (PF) equations, referred to as EPF, PPF, and HPF, for cohesive zone model (CZM) and Linear Elastic Fracture Mechanics (LEFM) PF models. The micro viscosity and micro inertia terms result in PPF and HPF, that can be solved explicitly in time. The additional advantage of the HPF is implying a finite damage propagation speed and a more favorable time advance limit. The desired micro-viscosity for the HPF is shown to correspond to a damping factor of one. The appropriate length and time scales, nondimensional equations, and (asymptotic) strain-stress solutions are provided for each differential equation. Two sources of rate sensitivity are discussed. First, when the fields are spatially uniform (0D solution) the rate effect arises from the form of differential equation. Asymptotic solutions show that at high loading rates, the energy dissipation has the rates of 2/3 and 1 for the PPF and HPF, respectively, with the former matching the Grady’s rate-sensitivity. The dynamic strength and failure strain show half of this rate. The analysis is extended to damage models with stress-based and bounded driving forces. Second, the rate effect arises from the deviation of 1D from 0D solutions as the damage exceeds a critical value and fragments form. Since this critical value tends to zero for quasi-static loading, this rate-effect is mainly present for low loading rates. This results in lower- and upper-shelf energy limits for the EPF at low and high loading rates, resembling some experimentally observed sigmoidal rate models for energy dissipation.

Stormwater treatment in constrained urban spaces through a hybrid Sequential Sedimentation Biofiltration System

Urban areas face increasing pressures on water resources, necessitating innovative approaches to climate adaptation and water quality management. Nature-based Solutions (NbS) offer a sustainable pathway, yet their integration with existing infrastructure in urban settings remains occasional. This study presents a novel hybrid system—Sequential Sedimentation Biofiltration System (SSBS)—designed for stormwater treatment within confined urban spaces. The system was adjusted to the existing stormwater infrastructure by integrating a sedimentation tank (SED), three Permeable Reactive Barriers (PRBs), and a biofiltration zone (BIO). The SSBS was evaluated for its efficiency in removing nutrients and sediments, focusing on the performance of PRBs. Our findings showed limited sediment removal in SED and PRBs due to spatial constraints and a high Hydraulic Loading Rate (HLR = 1.31 m/d), achieving an average of 13.6% Total Suspended Solids (TSS) removal. However, PRBs demonstrated effective removal of ammonium (43.4%) and phosphate (59.3%), potentially due to sorption and biofilm activity, with dominant microbial communities including Proteobacteria, Bacteroidetes, and nutrient-transforming taxa such as Nitrospirae. Interestingly, PRBs increased nitrite levels (57.1%) but did not significantly impact nitrate, chloride, or TSS. The BIO zone further enhanced nutrient retention (56% PO4–P) and served as a sink for TSS (52%). This study underscores the potential for integrating traditional urban infrastructure with NbS in a sequential stormwater treatment system, demonstrating its effectiveness in space-constrained urban environments.

Lumbar Spine Orientation Affects Compressive Fracture Outcome.

Understanding how spinal orientation affects injury outcome is essential to understand lumbar injury biomechanics associated with high-rate vertical loading. Whole-column human lumbar spines (T12-L5) were dynamically loaded using a drop tower to simulate peak axial forces associated with high-speed aircraft ejections and helicopter crashes. Spines were allowed to maintain natural lordotic curvature for loading, resulting in a range of orientations. Pre-test X-rays were used to quantify specimen orientation at the time of loading. Primary fracture types were identified (wedge, n = 6; burst, n = 4; hyperextension, n = 4) and compared for loading parameters and lumbar orientation. Fracture type was dependent on peak acceleration, bending moment, Cobb angle, sagittal spinal tilt, and location of the applied load. Lumbar spine orientation under high-rate axial acceleration affected the resulting fracture type. Analysis of pre-test X-rays revealed that spines that sustained wedge and burst fractures were oriented straighter at the time of loading. The load was applied centrally to T12 in spines with burst fractures, and anteriorly to T12 in spines with wedge fractures. Spines that sustained hyperextension fracture had lower peak accelerations, larger Cobb angles at the time of loading, and sustained larger extension moments. Fracture presentation is an important and understudied factor that influences biomechanical stability, clinical course, and long-term patient outcomes.