Contact Time Research Articles

Evaluation of characterization and adsorption kinetics of natural organic matter onto nitric acid modified activated carbon

Natural organic substances (NOM) found in drinking water are a major contributor to disinfectant by-product formation and are potentially toxic to humans. Traditional water treatment techniques may not always effectively treat NOMs. Therefore, an advanced treatment method such as adsorption can be inexpensive, simple and efficient. The selected adsorbent's and the NOMs properties both affect the removal effectiveness of the adsorption method. Activated carbon (AC), which is widely used in real-scale water treatment plants, has been modified and used in recent years In order to oxidize the porous carbon surface, raise its acidic qualities, eliminate mineral components, and enhance the surface's hydrophilic qualities. In this research, AC was modified with nitric acid (M-PAC) and NOM removal was investigated. In addition, it is discussed how the modification with nitric acid changes the adsorbent structure and chemistry. A morphology with smooth and irregular voids was observed as a result of nitric acid modification of the original AC by SEM analysis. The particle size increased from 387.65 nm to 502.07 nm for the M-PAC adsorbent. The FTIR spectrum indicates that structures connected to aromatic rings get formed in the M-PAC adsorbent as a result of the modification. The highest NOM removal for the original powdered activated carbon (PAC), 47%, was observed at 36 hours of contact time. On the other hand, M-PAC adsorbent achieved 40% NOM removal at contact times of 72 hours and above. It was concluded that the pseudo-second order kinetic model better represented NOM adsorption for both adsorbents.

The Oscillatory Behaviour of Cu-ZSM-5 Catalysts for N2O Decomposition: Investigation of Cu Species by Complementary Techniques.

Copper-exchanged ZSM-5 (Cu-ZSM-5) is a promising catalyst thanks to the Cu redox pair. A particular feature of this material consists in the presence of spontaneous isothermal oscillations which take place during N2O decomposition reaction, depending on the operating conditions. In the present work, a set of five Cu-ZSM-5 catalysts was synthesised by three procedures and three different copper precursor concentrations: i) wet impregnation, ii) single ion exchange, and iii) double ion exchange. Catalytic tests revealed that the ion-exchanged samples exhibit a low catalytic activity and no oscillatory behaviour, except for the twice-exchanged sample which achieves an average N2O conversion of 26 % at 400 °C. Conversely, the impregnated samples reach higher levels of N2O conversion (66 % for Cu5ZSM5_WI and 72 % for Cu10ZSM5_WI) and demonstrate a similar oscillating pattern. Further investigations disclosed that the most active catalysts, characterised by the presence of oscillatory behaviour, have more abundant and easily reducible copper species (ICP, EDX and H2-TPR) which interact better with the zeolitic support (FT-IR). Catalytic tests under a long time on stream (TOS) suggest that either self-organised patterns or deterministic chaos can be achieved during the reaction, depending on the operating conditions, such as temperature and contact time.

Double Droplets Impact an Inclined Superhydrophobic Surface.

The rebound dynamics of double droplets impacting an inclined superhydrophobic surface decorated with macro-ridges are investigated via lattice Boltzmann method (LBM) simulations. Four rebound regions are identified, that is, the no-coalescence-rebound (NCR), the partial-coalescence-rebound of the middle part bounces first (PCR-M), and the side part bounces first (PCR-S), as well as the complete-coalescence-rebound (CCR). The occurrence of the rebound regions strongly depends on the droplet arrangement, the center-to-center distance of the droplets, and the Weber number. Furthermore, the contact time is closely related to the rebound regions. The PCR-M region can significantly reduce the contact time because the energy dissipation in this region may decrease which can promote the rebound dynamic. Intriguingly, the contact time is also affected by the droplet arrangement; i.e., droplets arranged parallel to the ridge dramatically shorten the contact time since this arrangement increases the asymmetry of the liquid film. Therefore, for multidrop impact, the contact time can be effectively manipulated by changing the rebound region and the droplet arrangement. This work focuses on elucidating the wetting behaviors, rebound regions, and contact time of the multiple-droplet impacting an inclined superhydrophobic surface decorated with macro-ridges.

Prosthetic Stiffness and Added Mass Affect Metabolic Power and Asymmetry in Female Runners with a Leg Amputation.

Similar to non-amputees, female athletes with unilateral transtibial amputation (TTA) using running-specific leg prostheses (RSPs) may have worse running economy and higher rates of running-related injury than male athletes. Optimizing RSP configuration for female athletes could improve running economy and minimize biomechanical asymmetry, which has been associated with running-related injury. Nine females with a TTA ran at 2.5 m/s while we measured metabolic rates and ground reaction forces. Subjects used an RSP with a manufacturer-recommended stiffness category, one category less stiff and two categories less stiff than recommended. Use of an RSP two categories less stiff resulted in 3.0% lower net metabolic power (p=0.04), 7.8% lower affected leg stiffness (p=6.01x10-4), increased contact time asymmetry (p=0.04), and decreased stance average vertical ground reaction force asymmetry (p=0.04) compared to a recommended stiffness category RSP. Lower RSP stiffness (kN/m) values were associated with lower net metabolic power (p=0.02), lower affected leg stiffness (p=1.36x10-4), longer affected leg contact time (p=1.46x10-4) and similar affected leg peak and stance-average vertical ground reaction force compared to higher RSP stiffness values. Subjects then used the RSP stiffness category that elicited the lowest net metabolic power with 100 g, 200 g and 300 g added distally. We found no significant effects of added mass on net metabolic power, biomechanics, or asymmetry. These results suggest that female runners with a TTA could decrease metabolic power during running while minimizing biomechanical asymmetries, which have been associated with running-related injury using an RSP two categories less stiff than manufacturer recommended.

Importance of pyrolysis temperature and particle size on physicochemical and adsorptive properties of urban wood-derived biochar

Physicochemical properties of biochars made from urban wood waste at different pyrolysis temperatures (400-700 °C) and particle sizes (1-2 mm and 63-75 μm) were compared to their ability for heavy metals adsorption at various contact times (30-300 min) and adsorbent dosages (0.1-5 g L-1) in real landfill leachate. The yield, volatile matter, hydrogen and oxygen contents, and functional groups of biochars decreased with increasing pyrolysis temperature; while pH, electrical conductivity, ash, fixed carbon, and specific surface area (SSA) increased. FE-SEM images showed that the creation of pores on the surface of biochars increased significantly with increasing pyrolysis temperature. Moreover, particle size exhibited no significant effect on the properties of biochars (p>0.05), except for the SSA. The SSA of biochars with a particle size of 63-75 μm was significantly higher than that measured in 1-2 mm biochars. The adsorption efficiency of heavy metals from landfill leachate increases with increasing pyrolysis temperature, contact time and adsorbent dosage. Conversely, reducing the particle size increases the adsorption efficiency. The highest adsorption efficiency for Pb, Zn, Ni, Cd, and Mn was obtained as a result of using biochar pyrolyzed at 700 °C with a particle size of 63-75 μm (i.e., BC700/63-75) by 60.39%, 75.01, 64.36, 58.87%, and 71.15%, respectively. Pseudo second-order kinetic and the Langmuir isotherm were recognized as the most appropriate models to describe the adsorption process. The chemical adsorption was identified as the main mechanism for the adsorption of metal ions onto BC700/63-75.

Dry Reforming of CH4 Using a Microreactor

In the present study, a comparison of the dry reforming of a gas mixture containing methane, carbon dioxide and nitrogen without contaminants to a ruthenium-based Ru/Al2O3 catalyst was carried out in a microreactor for the first time. The influence of the contact time, temperature and composition of the feed on the conversion was exhaustively investigated. The optimal operating conditions were found to be a contact time of 80 milliseconds, a temperature of 700 °C and a CH4:CO2 ratio of 1. The assessment of diffusional limitations reveals that there is no resistance to mass transfer, which reveals the potential benefit of the determination of intrinsic reaction kinetics within a microreactor.

Adsorptive decolorization of brilliant green dye in aqueous media using various modified MOF-5 adsorbents

Dye pollution in environmental water is a serious problem worldwide, posing significant environmental and health concerns. To effectively address this problem, this study investigates the adsorptive decolorization of brilliant green (BG) dye in aqueous media by using various metal-organic frameworks (MOF-5)-based adsorbents modified with industrial wastes (coal fly ash (CFA) and rice husk ash (RHA)). The adsorption experiments were conducted to evaluate their performance under varying conditions, and the synthesized and spent adsorbents (selected) were characterized. The results showed that the adsorbent samples possessed the characteristics of a good adsorbent. MOF-5 coated with thermally treated RHA at 900 °C (MOF-5@ RHA900 – with BET surface area = 91.6810 m2 g−1) has the highest observed BG dye adsorption efficiency (92%) and adsorption capacity (30.22 mg g−1) at adsorbent mass of 1.4 g, contact time of 2 h, and initial dye concentration of 20 mg L−1. BG dye removal increased with an increase in contact time and adsorbent amount and decreased with an increase in initial dye concentration. The adsorption kinetics and isotherm equilibrium studies revealed that the adsorption data were best fitted to the pseudo-second-order kinetic model (R2 = 0.9507) and Langmuir isotherm model (R2 = 0. 0.9929), respectively. These findings highlight the potential of mesoporous MOF-5@ RHA900 as an effective adsorbent for BG dye decolorization in aqueous media, with implications for water treatment and the utilization of industrial waste materials.

Preparation of thiourea derivative incorporated Ag3PO4 core shell for enhancement of photocatalytic degradation performance of organic dye under visible radiation light

Photocatalysis is a promising technique to reduce hazardous organic pollutants using semiconductors under visible light. However, previous studies have been concerned with the behavior of silver phosphate (Ag3PO4) as n-type semiconductors, and the problem of their instability is still under investigation. Herein, 4,4′-(((oxalylbis(azanediyl)) bis(carbonothioyl)) bis(azanediyl)) dibenzoic acid is synthesized by green method and used to enhance the photocatalytic behavior for Ag3PO4. The incorporated Ag3PO4 core–shell is prepared and characterized via XRD, FT-IR, Raman, TEM and BET. Besides, the thermal stability of the prepared core shell was investigated via TGA and DSC measurements. The optical properties and the energy band gap are determined using photoluminescence and DRS measurements. The photodegradation of methylene blue in the presence of the synthesized Ag3PO4 core–shell under visible light is examined using UV/Vis measurements. The effect of initial dye concentration and contact time are studied. In addition, the kinetic behavior of the selected dye during the photodegradation process shows a pseudo-first order reaction with rate constant of 0.015 min−1 for ZAg. The reusability of the Ag3PO4 core shell is evaluated, and the efficiency changed from 96.76 to 94.02% after three cycles, indicating efficient photocatalytic behavior with excellent stability.

Adsorption Behavior of Co2+, Ni2+, Sr2+, Cs+, and I- by Corrosion Products α-FeOOH from Typical Metal Tanks.

Throughout the nuclear power production process, the disposal of radioactive waste has consistently raised concerns about environmental safety. When the metal tanks used for waste disposal are corroded, radionuclides seep into the groundwater environment and eventually into the biosphere, causing significant damage to the environment. Hence, investigating the adsorption behavior of radionuclides on the corrosion products of metal tanks used for waste disposal is an essential component of safety and evaluation protocols at disposal sites. In order to understand the adsorption behavior of important radionuclides 60Co, 59Ni, 90Sr, 135Cs and 129I on α-FeOOH, the influences of different pH values, contact time, temperature and ion concentration on the adsorption rate were studied. The adsorption mechanism was also discussed. It was revealed that the adsorption of key nuclides onto α-FeOOH is significantly influenced by both pH and temperature. This change in surface charge corresponds to alterations in the morphology of nuclide ions within the system, subsequently impacting the adsorption efficiency. Sodium ions (Na+) and chlorate ions (ClO3-) compete for coordination with nuclide ions, thereby exerting an additional influence on the adsorption process. The XPS analysis results demonstrate the formation of an internal coordination bond (Ni-O bond) between Ni2+ and iron oxide, which is adsorbed onto α-FeOOH.

The valorization of Prunus mahaleb shell through acid modification for the sorption of Pb2+ removal from aqueous solution

AbstractThis study aimed to investigate the biosorption performance of acid-modified waste Prunus mahaleb (PMA) shells in the removal of Pb2+ ions from aqueous solutions. Changes in the morphological properties and functional components of PMA biosorbent were characterized using SEM–EDX, FT-IR, BET, and PZC analyses. The effect of various parameters such as initial Pb2+ concentration, pH, PMA dosage, contact time, and temperature on biosorption was investigated using a batch biosorption procedure. The maximum biosorption capacity, determined using the Langmuir isotherm, was calculated to be 119 mg g−1. It was found that the biosorption kinetic mechanism followed pseudo-second-order kinetics and intraparticle diffusion model. According to the determined thermodynamic parameters, the biosorption mechanism was found to be endothermic (ΔH° > 0), spontaneous (ΔS° > 0), and entropy-increasing (ΔG° < 0). The outcomes of the experiment were evaluated in comparison to other sorbents that have been previously commonly used in the literature. It was demonstrated that PMA could be a promising, environmentally friendly, cost-effective, and sustainable potential biosorbent for the removal of Pb2+ ions.

Enhancing Wastewater Depollution: Sustainable Biosorption Using Chemically Modified Chitosan Derivatives for Efficient Removal of Heavy Metals and Dyes.

Driven by concerns over polluted industrial wastewater, particularly heavy metals and dyes, this study explores biosorption using chemically cross-link chitosan derivatives as a sustainable and cost-effective depollution method. Chitosan cross-linking employs either water-soluble polymers and agents like glutaraldehyde or copolymerization of hydrophilic monomers with a cross-linker. Chemical cross-linking of polymers has emerged as a promising approach to enhance the wet-strength properties of materials. The chitosan thus extracted, as powder or gel, was used to adsorb heavy metals (lead (Pb2+) and copper (Cu2+)) and dyes (methylene blue (MB) and crystal violet (CV)). Extensive analysis of the physicochemical properties of both the powder and hydrogel adsorbents was conducted using a range of analytical techniques, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and scanning electron microscopy (SEM), as well as 1H and 13C nuclear magnetic resonance (NMR). To gain a comprehensive understanding of the sorption process, the effect of contact time, pH, concentration, and temperature was investigated. The adsorption capacity of chitosan powder for Cu(II), Pb(II), methylene blue (MB), and crystal violet (CV) was subsequently determined as follows: 99, 75, 98, and 80%, respectively. In addition, the adsorption capacity of chitosan hydrogel for Cu(II), Pb(II), MB, and CV was as follows: 85, 95, 85, and 98%, respectively. The experimental data obtained were analyzed using the Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. The isotherm study revealed that the adsorption equilibrium is well fitted to the Freundlich isotherm (R2 = 0.998), and the sorption capacity of both chitosan powder and hydrogel was found to be exceptionally high (approximately 98%) with the adsorbent favoring multilayer adsorption. Besides, Dubinin has given an indication that the sorption process was dominated by Van der Waals physical forces at all studied temperatures.

Synthesis of zero valent copper/iron nanoparticles using Piper betle leaves for the removal of pharmaceutical contaminant atorvastatin

In this study, bimetallic Cu–Fe nanoparticles were synthesized using the green approach with Piper betle leaves, and the removal efficiency of one of the pharmaceutical compounds, Atorvastatin, was investigated. UV, SEM, FTIR, EDAX, particle size, and zeta potential measurements were used to confirm nanoparticle fabrication. The removal efficiency of Atorvastatin (10 mg/L) by bimetallic Cu–Fe nanoparticles was 67% with a contact time of 30 min at pH 4, the adsorbent dosage of 0.2 g/L, and stirring at 100 rpm. Piper betle bimetallic Cu–Fe nanoparticles have demonstrated excellent stability, reusability, and durability, even after being reused five times. Furthermore, the synthesized bimetallic Cu–Fe nanoparticles demonstrated remarkable antimicrobial properties against gram-negative strains such as Escherichia coli and Klebsiella pneumoniae, gram-positive strains such as Staphylococcus aureus and Bacillus subtilis, and fungi such as Aspergillus niger. In addition, the antioxidant properties of the synthesized bimetallic Cu–Fe nanoparticles were assessed using the DPPH radical scavenging assay. The results indicated that the nanoparticles had good antioxidant activity. Thus, using Piper betle extract to make Cu–Fe nanoparticles made the procedure less expensive, chemical-free, and environmentally friendly, and the synthesized bimetallic Cu–Fe nanoparticles helped remove the pharmaceutical compound Atorvastatin from wastewater.

Efficient treatment of secondary treated refinery wastewater using sand biofiltration: Removal of hazardous organic pollutants

This study explored the potential of sand biofiltration for tertiary treatment of real refinery wastewater. The biofilter (2 cm (I.D.) x 15 cm (L)) operated on secondary treated refinery wastewater at flow rate of 1 mL/min had empty bed contact time (EBCT) of 47.12 min for one circulation. Maximum reduction in COD after 4, 8 and 12 times recirculation was 25 %, 52 % and 56 %; while the TOC reduction was 33 %, 43 % and 51 %, respectively, after biofilm development over 30 days. Quantification using two dimensional gas chromatography – time of flight mass spectrometry (GCxGC-TOF MS) revealed that several of the identified target compounds could not be detected in the wastewater after 12 recirculations. After 8 times recirculation, most of the compounds showed very high removal efficiency. For biofiltration over the flow rate range 2–10 mL/min, the reduction in COD and NH4+-N ranged from 62–73 % and 78–86 %, respectively, after 8 times recirculation. The nitrite concentration first increased and subsequently decreased, while the nitrate concentration continuously increased with increase in the number of recirculations. Solid phase micro-extraction (SPME) analysis of the aqueous phase using GCxGC-TOF MS and a semi-quantitative approach indicated that the removal of predominant classes of compounds was greater than 95 % after 8 times recirculation, with maximum reduction occurring in the first pass through the biofilter. Assimilable organic carbon (AOC) reduction was 98 % after 8 times recirculation. Metagenomic analysis revealed that Proteobacteria was the most dominant phylum in the biofilter. Many known polynuclear aromatic hydrocarbon (PAH) degraders, such as Sphingomonadales, Burkholderiales, Rhodobacterales and Rhodospirillales, were found in the biofilter leading to high removal efficiency of hazardous organic pollutants.

Rebound characteristics of a water droplet impacting on a superhydrophobic cone

Precise control of droplet rebound behavior on superhydrophobic surfaces is essential for various industrial applications like anti-icing and self-cleaning. However, current studies still lack a comprehensive understanding of this phenomenon. Herein, we conduct a numerical investigation on the rebound dynamics of water droplets impacting on superhydrophobic conical cones under various Weber numbers and cone angles. A phase diagram illustrating impact outcome transitions from non-impalement to impalement and ring bouncing is presented. A semi-empirical model is proposed to identify the impalement transition by correlating critical Weber number with cone angle. While ring bouncing reduces contact time by up to 47 % compared to flat surfaces, it is a transient regime due to low rebound velocity, causing the liquid ring to recontact the cone and eventually rebound from the cone tip in a conventional manner with a prolonged contact time. We also observe attractive phenomena upon ring bouncing, including periodically oscillating radial extension and rapid rotation. Shorter contact times in conventional bouncing are achieved at larger cone angles and lower Weber numbers by minimizing radial expansion and falling distance. Furthermore, a theoretical model that accurately predicts the contact time of ring bouncing is developed. It is demonstrated that rebound velocities in both conventional and ring bouncing rise as cone angle decreases, attributed to reduced viscous dissipation and surface energy. Notably, in conventional bouncing, rebound velocity increases by 63 % on average compared to flat surfaces when the cone angle is 60°.

Uncalcined Zn/Al Carbonate LDH and Its Calcined Counterpart for Treating the Wastewater Containing Anionic Congo Red Dye

In this investigation, Zn/Al carbonate layered double hydroxide (ZAC-LDH) and its derived material on calcination were synthesized for removing the anionic azo dye Congo red (CR) from wastewater. Numerous factors were methodically investigated, including temperature, adsorbent dosage, pH, starting Dye Concentration (DC), and contact time. The CR elimination percentage dropped as the initial DC increased from 25 mg/L to 100 mg/L at 30 °C for uncalcined LDH, and from 97.96% to 89.25% for calcined LDH. The pH analysis indicates that the highest level of dye removal was recorded within the acidic pH range through the electrostatic attraction mechanism. The sorption kinetics analysis results demonstrated that the pseudo-second-order kinetic model exhibited a stronger fit to both uncalcined LDH and CZA-LDH, with the maximum correlation coefficient value. The Van’t Hoff plots indicate the spontaneous nature of the physisorption process with a negative ΔG° (<−20 kJ/mol), while the endothermic adsorption process exhibited a positive ΔH°. The X-ray diffraction of calcined LDH reveals a significant intercalation of CR dye molecules, both prior to and following adsorption, showcasing a distinctive memory effect. The Brunauer–Emmett–Teller (BET) gas sorption measurements were performed to support the mesoporous nature of ZAC-LDH and CZA-LDH. The FTIR spectrum confirms the interaction of dye molecules on the surface of uncalcined and calcined LDH. These findings emphasize the efficacy of both the synthesized LDHs in removing CR dye, with CZA-LDH demonstrating superior efficiency compared to uncalcined LDH in the context of CR removal from wastewater.

Probing structural features in potato starch granules at moderate hydration through the modelling of 1H->13C polarization transfer kinetics

The structural arrangement of starch polymers in presence of water is known to impact the functional properties of starchy products. In this study, the hydration of potato starch granules was investigated at the molecular level through various 1H->13C polarization transfer solid-state Nuclear Magnetic Resonance (ss-NMR) experiments. The impact of increasing the water content from 12.3 % to 45.9 % was assessed using 13C Cross Polarization Magic Angle Spinning (CPMAS), Variable Contact Time (VCT-CPMAS), Variable Spin Lock (VSL-CPMAS), and T One Rho QUEnching (TORQUE) NMR sequences. Of these, VCT-CPMAS proved to be the most promising. When applied with an optimal number of contact times, it enabled the application of several mathematical models that provided detailed insights into the structuring of protons in the hydrated potato starch granules. At low hydration (12.3 %), the models enabled various structural domains to be distinguished, which we suggest are associated with helical and amorphous structures. At moderate hydration (45.9 %), we tested two fitting models. Two pools of protons were revealed, corresponding to loosely ordered structures on the scale of tens of nanometers. These findings suggest varying water distribution during starch hydration and are likely to indicate variable hydration levels in the multilamellar amorphous structures of starch granules.

Stability of Running Stride Biomechanical Parameters during Half-Marathon Race

This study explores the stability of biomechanical parameters of the running stride of male trained athletes during a half-marathon competition. Using a field-based descriptive design, eight male athletes from a local training group were monitored throughout an official half-marathon race under identical conditions, assessing biomechanical parameters including ground contact time (GCT), leg spring stiffness (LSS), vertical oscillation (VO), and stride length (SL) recorded via the Stryd Summit Power Meter. A repeated measures analysis of variance (RM ANOVA) was conducted to detect significant changes in biomechanical parameters as the race progressed. Results demonstrated minimal changes in all parameters, with no significant differences observed for GCT (F = 0.96, p = 0.38), VO (F = 0.23, p = 0.87), and SL (F = 1.07, p = 0.35), and a small (η2 = 0.004) yet statistically significant difference in LSS (F = 5.52, p = 0.03) between the first and second segments, indicating that athletes were able to maintain stable biomechanical parameters throughout the race. The conclusion highlights the need for personalized training programs tailored to the unique biomechanical adaptations and demands of endurance running.

Barefoot pressure distribution of diabetic patients and non-diabetic volunteer subjects after sensorimotor training with an unstable shoe construction

BackgroundForty-three percent of all diabetic foot ulcers occur under the medial forefoot due to a medial deviation of elevated pressures and premature forefoot ground contact in neuropathic diabetic patients. A 6-week sensorimotor training period with an unstable shoe construction reduces in-shoe peak pressures and contact times under the medial aspect of the forefoot. MethodsThe study was designed as a Randomised Control Trial with two diabetic groups (one served as intervention group and one as control group) and one non-diabetic intervention group. Measurements for barefoot pressure distribution and contact times were taken by means of an Emed® pressure measurement platform (Novel GmbH, Munich) before and after 6 weeks. During this time the diabetic and the non-diabetic intervention groups were required to wear an unstable shoe construction (Masai Barefoot Technology, MBT®) for at least four hours per day. FindingsResults for the non-diabetic intervention group showed significantly later contact times for the medial portion of the forefoot, resulting in shorter contact times. Peak pressure was also reduced under the medial aspect of the foot while it was increased under the lateral aspect of the foot. Changes for the diabetic intervention group followed the same pattern while the values of the diabetic control group shifted away from the reference values. InterpretationA 6-week sensorimotor training period with an unstable shoe construction can change barefoot peak pressures and contact times in non-diabetic subjects and in diabetic patients in the most endangered area, i.e. the medial forefoot.

Enhanced removal of lead and zinc by a 3D aluminium sulphate-functionalised graphene aerogel as an effective adsorption system

The discharge of heavy metals into the environment has adversely affected the aquatic ecosystem due to their toxic and non-biodegradable nature. In this research, a three-dimensional graphene oxide/carboxymethylcellulose/aluminium sulphate (GOCAS) aerogel was synthesised and evaluated as a novel means for lead and zinc removal. The GOCAS aerogel was prepared via ice-templating of graphene oxide with carboxymethylcellulose and aluminium sulphate as the crosslinking and functionalisation additives. Characterisation of the aerogel by various analytical techniques confirmed the successful integration of the chemical additives. The hydroxyl and sulphate groups in the aerogel were found to participate in the adsorption of both metals. The equilibrium of lead adsorption was found to correlate well to the Freundlich isotherm, while zinc adsorption fitted closely the Langmuir isotherm. The kinetic adsorption behaviour of both metals was best described as pseudo-second-order. The interactive influences of concentration, temperature, contact time and adsorbent dose on the metal removal were explored by a central composite design, and the optimum adsorption capacity for lead was determined to be 138.7 mg/g at a GOCAS dose of 20 mg, initial concentration of 100 mg/L, temperature of 50 °C and contact time of 45 min. The optimum adsorption capacity for zinc was 52.69 mg/g at 30 mg, 65 mg/L, 45 °C and 40 min. Furthermore, regeneration studies with hydrochloric acid eluant were successfully conducted for up to four adsorption-desorption cycles. Overall, this work demonstrates that GOCAS aerogel is a viable nanosorbent for the adsorption of lead and zinc from water systems.

Assessing Trail Running Biomechanics: A Comparative Analysis of the Reliability of StrydTM and GARMINRP Wearable Devices.

This study investigated biomechanical assessments in trail running, comparing two wearable devices-Stryd Power Meter and GARMINRP. With the growing popularity of trail running and the complexities of varied terrains, there is a heightened interest in understanding metabolic pathways, biomechanics, and performance factors. The research aimed to assess the inter- and intra-device agreement for biomechanics under ecological conditions, focusing on power, speed, cadence, vertical oscillation, and contact time. The participants engaged in trail running sessions while wearing two Stryd and two Garmin devices. The intra-device reliability demonstrated high consistency for both GARMINRP and StrydTM, with strong correlations and minimal variability. However, distinctions emerged in inter-device agreement, particularly in power and contact time uphill, and vertical oscillation downhill, suggesting potential variations between GARMINRP and StrydTM measurements for specific running metrics. The study underscores that caution should be taken in interpreting device data, highlighting the importance of measuring with the same device, considering contextual and individual factors, and acknowledging the limited research under real-world trail conditions. While the small sample size and participant variations were limitations, the strength of this study lies in conducting this investigation under ecological conditions, significantly contributing to the field of biomechanical measurements in trail running.