Continuous Mode Research Articles

Scalable approach for growing hexagonal boron nitride on silicon and its role in III-nitride van der Waals epitaxy

Hexagonal boron nitride (h-BN) stands out among 2D materials for its insulating properties, making it promising for the integration of 2D and 3D materials. However, achieving wafer-scale growth on silicon substrates remains a significant challenge. In this study, growth strategies for depositing h-BN on Si substrates are explored utilizing the wafer scalable metalorganic chemical vapor deposition. Our investigations reveal that employing a pulsed flow mode scheme is preferable over the conventional continuous flow mode scheme in growing h-BN thin films on 150 mm Si substrates. The as-grown h-BN film on Si exhibits uniform coverage with h-BN[0001]//Si[111]. With the successful wafer-scale growth of h-BN on Si, its role in aiding the van der Waals epitaxy of III-nitrides on Si substrates and subsequent epitaxial lift-off (ELO) of III-nitrides is further exemplified. An optimized h-BN thickness for the ELO process is also determined.

Dentinal tubule occlusion effects of dipotassium oxalate and diode laser combination: a single-blind in vitro study.

Dentin hypersensitivity (DH) affects many patients. Various therapeutic options have been devised to alleviate this condition by achieving dentinal tubules (DT) occlusion. This research aimed to investigate the effects of dipotassium oxalate-containing mouthwash, diode laser and their combination on DT occlusion. Forty dentin samples were obtained from 20 human single-rooted third molars, 40 dentin specimens were obtained, and exposed DT were created in vitro. They were assigned into four groups: Group 1 (n = 10), the control group where no treatment was applied; Group 2 (n = 10), a mouthwash with a 1.4% dipotassium oxalate was applied twice for 60s during a 5-day period in a shaker at 100rpm; Group 3 (n = 10), a combination of the same mouthwash and an 810nm diode laser at an output power of 0.25W in continuous mode was applied for 60s without contact at a distance of 3-4mm; and Group 4 (n = 10), only a diode laser with the same protocol was applied. Occlusion of the DT was observed by scanning electron microscopy. The analysis revealed occlusion of the DT in all treatment groups; however, the effects were more pronounced in the combined treatment group (Group 3). Compared with the test groups, the control group had significantly more open DT in 100 µm2 (p < 0.01). The difference between the Group 2 and Group 4 was not significant (p > 0.05). DT occlusion was achieved via the use of a mouthwash containing 1.4% dipotassium oxalate and an 810nm diode laser. However, the combination resulted in the greatest results and therefore may be utilized in individuals with DH.

A New Third-Order Continuous Sliding Mode Speed and DC-Link Voltage Controllers for a PMSG-based Wind Turbine with Energy Storage System

A New Third-Order Continuous Sliding Mode Speed and DC-Link Voltage Controllers for a PMSG-based Wind Turbine with Energy Storage System

Pressure reduction and suction characteristics of the new digital single use flexible ureteroscope with suction: an in-vitro experimental study.

To assess the time taken by the single use 7.5Fr suction flexible ureteroscope to reduce pressure under 40mm Hg and to characterize the behavior of stones, fragments and dust during suction activation. An in vitro setting was developed for this experiment. A saline-filled globe, with the 7.5Fr single-use suction flexible ureteroscope, PU3033AH (ZhuHai Pusen Medical Technology Co, Ltd, Guangdon, China), an automatic irrigation pump and a pressure monitoring set were used at four modalities; i) continuous suction, no irrigation inflow; ii) continuous suction, irrigation inflow on; iii) one-second rate intermittent suction, irrigation inflow on, and iv) half-second rate intermittent suction, irrigation inflow on. The behavior of calcium oxalate stones from 0.5 to 5mm when being aspirated via the ureteroscope into a plastic container filled with saline was recorded. Suction with the PU3033AH worked properly with the inflow irritation on. The fastest strategy to lower the pressure was by continuously pressing the suction button with the irrigation inflow on. Overall, the median time to reach 40mg was roughly 3.5s. The PU3033AH could aspirate 0.5mm stones. The suction mode on a continuous pattern allowed the relocation of stones ranging from 1 to 5mm on an experimental setup with no obstacles. The PU3033AH was efficient in lowering pressure in a closed cavity mimicking the renal pelvis. Likewise, stone fragments under one millimeter were aspirated by the device whereas stones from one to five mm could be displaced when activating suction in continuous mode on an experimental setup with no obstacles.

From coffee waste to nutritional gold: bioreactor cultivation of single‐cell protein from Candida sorboxylosa

AbstractBACKGROUNDIndustrial effluents are continuously discharged into the environment. These wastewaters contain valuable compounds that can be reused for biotechnological applications. Coffee wastewater (CWW) is a powerful effluent that can be used for single‐cell protein (SCP) production reaching important content (up to 80%). Several yeast species can be used for SCP production, but Candida species are commonly applied for this purpose (17 species reported including the novel C. sorboxylosa). In addition, SCP can be produced in bioreactors under controlled conditions under three operation modes. Thus, batch mode is frequently used but continuous mode presents interesting advantages in economic terms, although it has been poorly applied in SCP production.RESULTSThe initial evaluation under batch operation mode showed that volumetric oxygen transfer coefficient (kLa of 101 h−1) improved biomass production (1.39 g L−1) and SCP yield (59.9%) in C. sorboxylosa. Thus, continuous mode was established at selected kLa and feeding with optimized medium composed of 87.5% (v/v) CWW, 1.38 g L−1 yeast extract, and 7.24 g L−1 (NH4)2SO4, in order to provided necessary nutrients. In this sense, the process presented higher values in dry cell weight and SCP productivity (0.57 and 0.29 g L−1·h, respectively), achieving a 3.35‐ and 2.90‐fold increase in biomass and protein productivity, respectively, compared to batch mode. The SCP from C. sorboxylosa exhibited an interesting essential amino acid profile under continuous mode (33.704%).CONCLUSIONThe bioprocess highlights several advantages during bioreactor cultivation, including: (i) reduced energy consumption for temperature control; (ii) successful establishment of an initial continuous operation mode with promising performance; and (iii) SCP from C. sorboxylosa exhibited a notable composition of essential amino acids, which could be beneficial for potential use in animal feed. © 2024 Society of Chemical Industry (SCI).

Comparison of different techniques used for inferior alveolar nerve block anaesthesia regarding the pain caused in cooperative children.

The aim of this study is to compare the application of inferior alveolar nerve block (IANB) anaesthesia in children with traditional plastic syringe (TPS) and computer-controlled injection device Dentapen® using two different modes [continuous mode (DC) and ramp-up mode (DR)] in terms of pain. This study included 96 children aged 7-12 who were determined to be positive (3) or definitely positive (4) according to the Frankl Behaviour Evaluation Scale and in need of treatment who had IANB anaesthesia indication in the right and left regions. Patients were divided into three groups and compared in terms of pain felt during IANB anaesthesia according to heart rate, oxygen saturation, Wong Baker Pain Rating Scale, Face Legs Activity Cry Consolability Pain Scale and patient preference distributions. Heart rate values increased significantly during the injection of IANB anaesthesia with all methods [TPS, DC and DR methods (p < 0.05)]. No significant differences were found in terms of pain between the TPS, DC and DR methods in the intragroup and intergroup assessments. However, among the patient preferences of TPS and DC methods, the number of patients who preferred the DC method was found to be statistically significantly higher those who preferred the TPS method (p = 0.026). Although the TPS group scored higher than the Dentapen® groups in terms of pain, the difference between the investigated IANB anaesthesia techniques was not statistically significant. However, the majority of the patients preferred the Dentapen® device compared to the TPS. It appears that more research is needed on the Dentapen® device in local anaesthesia applications in children.

Stability and receptivity analyses of the heated flat-plate boundary layer with variable viscosity

This article presents the modal, non-modal, and resolvent analyses of the boundary layer developed over a heated flat-plate with temperature-dependent viscosity using linear stability theory. The governing equations are derived in the normal velocity–vorticity form by imposing small infinitesimal disturbances on the base flow with the Oberbeck-Boussinesq (OB) approximation. The spectral method is employed to discretize the governing stability equations in the wall-normal direction. The base flow comes from the similarity solution using R-K4th order method along with shooting techniques. The effects of viscosity stratification, inertia, shearing, and buoyancy on the stability of the boundary layer are investigated by varying the sensitivity parameter (ϵ), Reynolds (Re), Prandtl (Pr), and Richardson numbers (Ri). The modal analysis shows the time-asymptotic behavior of the disturbances and onset of instability is mainly caused by amplification of Tollmien–Schlichting (T-S) waves similar to as observe in the traditional Blasius case. The modal stability increases with increase in sensitivity parameter and stabilizing effects become more pronounced for liquid than gas. However, the thermal effects lead to destabilize the flow and strong destabilizing effects produced for higher Prandtl number. On the other hand, non-modal analysis displays an early transient growth of disturbances and an existence of these non-normality effects identified from the pseudospectra via. resolvent analysis. The non-modal growth increases with increase in ϵ even though T-S modes shift towards the damped region, which indicates the continuous modes in the eigenspectrum are more dominated than the discrete T-S modes due to the thermal effects. To clarify this qualitative change, a component-wise input–output analysis is performed to measure the receptivity to particular external disturbances. The results show the thermal energy of the disturbances is converted into kinetic energy due to thermal effects, resulting in strong receptivity amplification at the continuous mode due to the non-normality of the linear operator. Thus, the boundary layer under the influence of viscosity stratification, heating, and shearing effects is vulnerable to free-stream disturbances that could significantly affect bypass transition

Real-time monitoring of aqueous total N-nitrosamines by UV photolysis and chemiluminescence.

N-nitrosamines such as N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), and N-nitrosopyrrolidine (NPYR) have been established as potent carcinogens that can induce diverse types of cancer. Several studies have extensively investigated the accurate quantification of total N-nitrosamines (TONO) and the intricate nature of the matrix in which they are detected. The potential for the formation of N-nitrosamines in post-combustion CO2 capture (PCCC) and water treatment has raised concerns. This study outlines a unique method for the quantification of TONO in aqueous matrices using UV photolysis and the subsequent detection of NO by chemiluminescence. This method offers benefits such as operation in the continuous mode and handling of high sample flow rates to achieve a low limit of detection (LOD) and a low limit of quantification (LOQ). The observed LODs for the individual N-nitrosamines of NDMA, N-nitrosomorpholine (NMOR), N-nitrosodibutylamine (NDBA), and NPIP range between 0.06 and 0.2µM at a sample flow rate of 0.25mL/min, while the LOD range is reduced to between 0.02 and 0.06µM at 0.75mL/min. Linear responses for the NO produced from specific N-nitrosamines are observed between 0.5 and 10µM. The developed method is resistant to interfering chemicals (i.e., nitrite, amines, and carbonyls) and exhibits high specificity.

The power of 810 nm near-infrared photobiomodulation therapy for human asthenozoospermia

Sperm motility is a crucial factor in male fertility. Photobiomodulation (PBM) has been reported to increase sperm motility, but a consistent approach suitable for identifying standardizable protocols is lacking. We collected asthenozoospermic (n = 70) and normozoospermic (n = 20) semen. The asthenozoospermic samples were irradiated with an 810 nm diode laser, in continuous wave mode, at 0.25 W, 0.5 W, 1 W and 2 W for 60 s on a circular area of 1 cm2 through a novel handpiece with an innovative flat-top profile. Sperm motility was assessed immediately, after 30 and 60 min. A sample size calculator, unpaired t-test and one-way ANOVA with post-hoc Tukey HSD tests were used for statistics. One and 2 W were the most effective outputs in increasing progressive motility compared to control (p < 0.001). The maximum effect was immediately after 1 W-PBM (p < 0.001) and decreased after 60 min (p < 0.001). Time physiologically decreased vitality (p < 0.001), but less in the 1 W-PBM samples (p < 0.05). 1 W-PBM did not affect chromatin condensation. Asthenozoospermic samples displayed an impairment of 80% in oxygen consumption and ATP production and a slight inefficiency of oxidative phosphorylation compared to normozoospermic samples (p < 0.001). 1 W-PBM partially restored the functionality of aerobic metabolism (p < 0.001) by recovery of oxidative phosphorylation efficiency. PBM did not affect lactate dehydrogenase (glycolysis pathway). No irradiated samples increased accumulated malondialdehyde, a marker of lipidic peroxidation. In conclusion, PBM improves progressive motility in asthenozoospermia through increased mitochondrial energetic metabolism without harmful oxidative stress.

Green synthesized nano-TiO2 from Tamarindusindica leaf extract for photo-degradation of combination of dyes by suspension and immobilization on inert supports

ABSTRACT The present study aims to use green synthesized TiO2 as a photocatalyst in suspended and immobilized form under UV light to efficiently degrade a combination of reactive dyes, namely titan yellow, methyl orange, rhodamine B, and methylene blue. TiO2 nanoparticles (NPs) were synthesized using Tamarindus indica leaf extract and were utilized to parametrically study photo-degradation at room temperature. The green synthesized NPs were characterized by Powder XRD, SEM, and FTIR techniques to understand the crystalline phase/purity, morphology, and functional groups respectively. The TiO2 in suspension under UV light showed >90% degradation towards a 10 ppm composite dye at a loading of 1.5 gL−1, pH 7, and an irradiation time of 120 min. Subsequently, TiO2 was further immobilized in-situ, on inert supports of perlite granules and glass and studied for catalytic activity in batch and continuous modes. The TiO2 nanoparticles immobilized on perlite granules and glass showed 59 and 48% degradation in batch operation under the same conditions as in suspended form. In continuous mode, the highest degradation activity was recorded at 2 Lh−1 after 4 passes. Further, kinetic studies reveal that the degradation reaction is best described by Langmuir Hinshelwood kinetics for both suspended and immobilized TiO2.

A New Three‐Port DC–DC Converter: Analysis, Design, and Verification for Hybrid Energy Systems

ABSTRACTA research study on the three‐port DC–DC converters is done in this article. The proposed converter is a power electronic unit with a low‐voltage, high‐voltage, and battery port. The power of the input ports can be transferred to the output port simultaneously and individually. In this converter, the power can flow bidirectional. In other words, the battery can be charged not only by the low‐voltage port but also by the returned energy from the high‐voltage port. Hence, the proposed converter can operate in step‐up and step‐down modes. Continuous input current, the low voltage stress on semiconductors, and the low count of the devices are other advantages of the converter. These features and the benefits mentioned above make the proposed converter proper for hybrid energy systems. This converter is analyzed in continuous conduction mode, resulting in mathematical equations. To validate these theoretical analyses, a laboratory scale of the converter performs at 50 kHz, 200 W, and 115 V.

Enhanced High‐Gain Switched Capacitor DC–DC Converter Optimizing Renewable Energy Integration

ABSTRACTA novel high‐gain switched capacitor (HGSC) DC–DC converter for carbon neutral energy applications is presented in the scientific paper. It consists of two MOSFET switches, and utilization of a simultaneous switching approach for the switches enables simplified control. The switched capacitor (SC) technique is utilized to extract high gain from the proposed HGSC topology; the basic idea is periodic charging and discharging of the capacitor. The proposed HGSC topology operational mode is carried out in Continuous Conduction Mode (CCM) along with the steady‐state analysis, and different switching stages are discussed in detail. Then, an analysis is carried out to demonstrate the proposed HGSC converter's special feature with other high‐gain converters. An averaging state‐space technique is used to determine the suggested converter's dynamics performance, and a small signal analysis is used to verify its stability. Furthermore, the HGSC topology is thoroughly analyzed in terms of power losses. For comparing the practical efficiency of the designed converter, nonidealities voltage gain is derived. The maximum efficiency of 96.7% is obtained at 150 W output power with the help of the dSPACE 1104 controller. Whenever the HGSC converter is fed with an input voltage supply of 20 V. It generates output voltages between 140 and 240 V. Extensive experimental investigation is carried out on a 200 W laboratory prototype model to verify the practicability and feasibility of HGSC DC–DC converter topology.

Spatiotemporal structure of flow field by a dielectric-barrier-discharge plasma actuator using phase-resolved particle image velocimetry

A typical dielectric-barrier-discharge plasma actuator (DBD-PA) operating in continuous mode generates a self-similar starting vortex followed by a quasi-steady wall jet. In the burst mode, it generates periodic vortices, leading to a spatially wider mean flow field. The characteristics of periodic vortices can be controlled by adjusting the duty cycle α and burst frequency fb of the actuation signal. In the present study, the flow field generated by the actuator in burst mode is studied for 50%≥α≤90%, and 10 Hz ≥fb≤90 Hz. The Reynolds number of mean flow based on the maximum induced velocity and jet half-width ranges from 171 to 524. High-speed laser-sheet visualization and time-resolved particle image velocimetry are used for flow field measurements. The flow field generated during burst mode operation shows the strong influence of the burst frequency. Periodic vortices with comparable size and convection speed of starting vortex are generated at low fb. Dipoles and small-scale vortices are formed at moderate fb similar to the behavior of a transitional wall jet. Kelvin–Helmholtz instability is observed at higher burst frequency. An ornamental vortex consisting of several small periodic vortices is formed at high values of fb during the starting period. Based on the temporal evolution of momentum, the flow field generated by the DBD-PA can be classified into (i) starting flow regime, (ii) transitional flow regime, and (iii) periodic flow regime. The self-similarity of the mean flow field generated by the DBD-PA is verified by comparing the mean velocity profile at multiple downstream locations with the self-similar solutions of laminar and turbulent wall jets. The entrainment coefficient of the mean flow field is similar to that of an axisymmetric turbulent wall jet. The bi-orthogonal analysis shows that both coherent mode energy content and the entropy are minimum (about 5% only) for the continuous mode actuation. For the burst mode actuation, both the coherent mode energy content and the entropy are higher in magnitude compared to that of continuous mode and decrease with increasing burst frequency. The vortices in the periodic flow regime are locked in with fb. The distance between subsequent vortices, λx and flow frequency, f follow a power-law relationship, λx=cf−n, where c is a constant and n can be approximated as 2/3.

Film-immobilized carbon nitride for the degradation of pharmaceuticals: A continuous flow photoreactor performance upheld by excitation-emission matrix fluorescence spectroscopy

The validation of immobilized photocatalysts is a fundamental matter regarding the scaling-up process in the photocatalytic degradation of aqueous pollutants in natural surface waters. This work presents the comprehensive evaluation of graphitic carbon nitride (g-C3N4, CN) immobilized onto a polymeric film (F) placed inside a continuous flow operation planar reactor for the removal of a mixture of pharmaceuticals (i.e., venlafaxine, citalopram, carbamazepine, tramadol, ketoprofen, and diclofenac, 3 μM each) under visible light. The resulting CN/F (8 mg of CN per cm2 of film and with significant preservation of optical and structural properties after more than 350 h of reuse) yielded the complete removal under total recirculation of all pharmaceuticals after 90 min under visible light, except for ketoprofen, probably ascribed to competition for photogenerated holes, as suggested by the proposed mechanism. Under dead-end continuous flow mode, the steady-state conversion averaged 67 % in deionized water, increasing up to 76 %, and 80 % in natural surface waters obtained from the Douro River and the effluent from a wastewater treatment plant (Northwestern Portugal), respectively, related to the promotion effect of carbonates anions and organic matter. The assessment of excitation-emission matrix (EEM) fluorescence spectroscopy coupled with parallel factor (PARAFAC) analysis further demonstrated the removal (ca. 50 %) of the protein- and humic-like substances contained in the collected wastewater, thus evidencing the continuous flow mode performance of the immobilized photocatalyst for real environmental applications.

Performance evaluation of resin wafer electrodeionization for enhanced nitrogen recovery from ammonium-containing water environment

Ammonium ion (NH4+) is a common pollutant from various sources like human and animal waste, industrial effluents, agricultural runoff, and commercial products, with traditional treatment methods often generating secondary contaminants, such as nitrite and nitrate. In this study, an energy-efficient resin-wafer electrodeionization (RW-EDI) process was employed for nitrogen recovery from ammonium-rich water. The system was operated in a continuous mode, with voltage-current curve measurements identifying a limiting current density of 2.2 A cm−2. With the NH4+ concentration of 1 g/L and a flow rate of 2.4 mL min−1, the system was tested at various cell voltages (1.2–7.2 V). The system could achieve 80 % NH4+ removal efficiency at a cell voltage of 3 V, current density of 2.2 A cm−2, influent NH4+ level of 3 g/L, and flow rate of 6.4 mL min−1. The observed current efficiency and the calculated power consumption were 41 % and 0.78 kWh m−3, respectively. Finally, a mass balance model was developed to predict the number of RW-EDI stacks for complete removal of NH4+ from the feed. Overall, the result from this study demonstrates that the RW-EDI-based system could be a promising technology for recovering nitrogen from wastewater.

Application of Atmospheric Cold Plasma (ACP) for Processing of Raw Bovine Colostrum: Investigation of Antimicrobial Efficacy of Different ACP Treatments

As a rich source of bioactive components, bovine colostrum (BC)1 can be used to produce valuable nutraceuticals. Achieving this goal with common thermal pasteurization processes is challenging due to the heat-sensitive nature of raw BC. This research aimed to investigate the potential of atmospheric cold plasma (ACP) as a novel non-thermal process in inactivating the microbial population in BC. Raw BC was treated with different ACP treatments, including direct dielectric barrier discharge (DBD) in both static and continuous modes, indirect DBD, corona discharge, and gliding arc discharge. The occurrence of creaming and curdling of BC during the treatments was one of the challenges of this research, which was the most and least severe during static and continuous treatments, respectively. The continuous and the indirect DBD treatments were the most and least effective in terms of microbial inactivation. The inactivation of natural microflora with the continuous ACP at the voltage of 15 kV for 20 min was approximately 98%. The indirect DBD treatment led to an increase in the microbial population of BC. In addition, the initial microbial population significantly affected the antimicrobial efficacy of ACP. Treatment voltage and time had a significant effect on the creaming and curdling, natural microflora population, and the total coliform population of the treated samples. The voltage of 14.5 kV and the exposure time of 14.2 min were determined as optimal treatment conditions by response surface methodology (RSM) to achieve the maximum reduction of microbial population, without pH changing of ACP-treated BC. The optimal treatment conditions of ACP reduced the total plate count and total coliform count of raw BC by 1.41 and 3.55 log CFU/ml, respectively, with a minor change in pH. These results promise the potential of ACP technology for BC processing.

Multi-objective design of fractional frequency-load control for hydro-thermal system considering nonlinear models and uncertainty

One of the crucial quantities in the power system problem is frequency, which should never exceed its nominal value. In normal conditions of load changes, the frequency is adjusted by automatic generation control. Still, in the face of special conditions, such as logging of the downstream network from the main network or a significant amount of generated power leaving the circuit, the power imbalance between generation and consumption causes a rapid frequency drop. In this case, the automatic generation control cannot stop the frequency drop, so the frequency tends toward instability. In this paper, to automatically produce a water-thermal system in two zones of discrete and continuous modes, the design of a fractional controller is discussed and investigated in different functional conditions and uncertainties. The proposed NSGA-II multi-objective method is used in this article to optimize each area’s load frequency control parameters for various goals. The ideal response for the entire network will be obtained by modifying these responses using a multi-factor method. This paper defines a multi-zone frequency load control based on time objective functions and eigenvalues. Based on the speed changes for the proposed algorithm and the novel approachfunction method employed in the control design. The simulation performed and analyzed in different working conditions with different comparative criteria has been discussed and investigated. Compared to more contemporary techniques, the simulation results show that the system’s performance is guaranteed. The main successes of the suggested method in comparison to earlier methods have been the reduction of overshoot, undershoot, and settling time.

Laser NIR Irradiation Enhances Antimicrobial Photodynamic Inactivation of Biofilms of Staphylococcus aureus.

Photodynamic inactivation (PDI) is a powerful technique for eradicating microorganisms, and our group previously demonstrated its effectiveness against planktonic cultures of Staphylococcus aureus bacteria using 5,10,15,20-tetrakis[4-(3-N,N-dimethylaminopropoxy)phenyl]porphyrin (TAPP) and visible light irradiation. However, biofilms exhibit a lower sensitivity to PDI, mainly due to limited penetration of the photosensitizer (PS). In the context of emerging antibacterial strategies, near-infrared treatments (NIRTs) have shown promise, especially for combating resistant strains. NIRT can act either through photon absorption by water, causing a thermal effect on bacteria, or by specific chromophores without a significant temperature increase. Our objective was to enhance biofilm sensitivity to TAPP-PDI by pretreatment with NIRT. This combined approach aims to disrupt biofilms and increase the efficacy of TAPP-PDI against bacterial biofilms. In vitro biofilm models of S. aureus RN6390 were utilized. NIRTs involved a 980 nm laser (continuous mode, 7.5 W/cm2, 30 s, totaling 225 J/cm2) post-TAPP exposure to enhance photosensitizer accumulation. Subsequent visible light irradiation at 180 J/cm2 was employed to perform PDI. Colony-forming unit counts evaluated the synergistic effect on bacterial viability. Scanning electron microscopy visualized the architectural changes in the biofilm structure. TAPP was extracted from bacteria to estimate the impact of NIRT on biofilm penetration. Using in vitro biofilm models, NIRT application following biofilm exposure to TAPP increased PS accumulation per bacteria. Under these conditions, NIRT induced a transient increase in the temperature of PBS to 46.0 ± 2.6°C (ΔT = 21.5°C). Following exposure to visible light, a synergistic effect emerged, yielding a substantial 4.4 ± 0.1-log CFU reduction. In contrast, the PDI and NIRT treatments individually caused a decrease in viability of 0.9 ± 0.1 and 0.8 ± 0.2-log respectively. Interestingly, preheating TAPP-PBS to 46°C had no significant impact on TAPP-PDI efficacy, suggesting the involvement of thermal and nonthermal effects of NIR action. In addition to the enhanced TAPP penetration, NIRT dispersed the biofilms and induced clefts in the biofilm matrix. Our findings suggest that NIR irradiation serves as a complementary treatment to PDI. This combined strategy reduces bacterial numbers at lower PS concentrations than standalone PDI treatment, highlighting its potential as an effective and resource-efficient antibacterial approach.

Filtro empacado con residuos de lodos de Al para la eliminación de fósforo como sistema de pulimento en una planta de tratamiento de aguas residuales

Recently, using residual aluminum sludge (Al-sludge) from drinking water treatment plants for phosphorus removal has been assessed and it has shown to be highly efficient. However, most of the studies have been conducted using synthetic water. Only a few works have applied this method to real wastewater (WW), and none of them have been tested in continuous mode, as a polishing step, in a pilot-scale, decentralized wastewater treatment plant (WWTP). This paper aimed to evaluate the performance of an immersed filter packed with a bed of residual Al-sludge as a polishing system for Phosphorous removal, in a pilot-scale, decentralized WWTP. The study determined at laboratory-scale the capacity for phosphorus removal through batch and continuous tests using both synthetic and real wastewater and evaluated the effect of retention time. Based on the results, an Al-sludge immersed filter (Al-sludge Filter) at pilot-scale was constructed, implemented, and evaluated as a polishing step for the effluent of a decentralized-WWTP. The results showed that during continuous testing with real WW, the phosphorus removal capacity was 2.55 mg P-PO43-∙g-1 per gram of Al sludge using a retention time of 120 min. The Al-sludge filter as a polishing system presented an average removal efficiency of 94 ± 8 % and an effluent concentration of under 0.50 mg P-PO43-∙l-1 during the first 20 operational days. For the next 17 days, the system removed 85 ± 9 % on average, showing an effluent concentration of under 1.0 mg P-PO43-∙l-1. From operational day 32 onwards, the removal efficiency was 63.6 ± 10.7 %, with an average effluent concentration of 2.20 ± 0.39 mg P-PO43-∙l-1.

Extra-framework cations promoted zeolite-encaged cobalt catalysts towards efficient ethylbenzene dehydrogenation

The transformation of ethylbenzene to styrene through direct dehydrogenation is essential process in chemical industry, indispensable for the synthesis of polymers and plastics. Herein, faujasite zeolite encaged cobalt catalyst with potassium ion as the extraframework cations, namely K-Co@Y, is reported to be a robust catalyst for ethylbenzene direct dehydrogenation, showing ethylbenzene conversion of ∼45 % and styrene selectivity of ∼95 % simultaneously under employed conditions. The superior performance of K-Co@Y in comparison with Na-Co@Y is attributed to the effective modulation of zeolite-encaged Co2+ species by extraframework K+ ions, which increases the electron density of cobalt sites and facilitates CH bond activation. Although coke deposits cause gradual deactivation, the structural integrity of K-Co@Y can be well preserved during the dehydrogenation reaction and the performance can be full restored via a simple calcination regeneration step, making K-Co@Y an eligible catalyst for long-term running in the continuous regeneration mode. This study highlights the vital role of extraframework cations in zeolite-encaged single-site catalysts for target chemical transformations and opens up a new way to modulate the performance of zeolite catalysts.