Operation Period Research Articles

Chromium-Induced High Covalent Co-O Bonds for Efficient Anodic Catalysts in PEM Electrolyzer.

The proton exchange membrane water electrolyzer (PEMWE), crucial for green hydrogen production, is challenged by the scarcity and high cost of iridium-based materials. Cobalt oxides, as ideal electrocatalysts for oxygen evolution reaction (OER), have not been extensively applied in PEMWE, due to extremely high voltage and poor stability at large current density, caused by complicated structural variations of cobalt compounds during the OER process. Thus, the authors sought to introduce chromium into a cobalt spinel (Co3O4) catalyst to regulate the electronic structure of cobalt, exhibiting a higher oxidation state and increased Co-O covalency with a stable structure. In-depth operando characterizations and theoretical calculations revealed that the activated Co-O covalency and adaptable redox behavior are crucial for facilitating its OER activity. Both turnover frequency and mass activity of Cr-doped Co3O4 (CoCr) at 1.67V (vs RHE) increased by over eight times than those of as-synthesized Co3O4. The obtained CoCr catalyst achieved 1500mA cm-2 at 2.17V and exhibited notable durability over extended operation periods - over 100h at 500 mA cm-2 and 500h at 100 mA cm-2, demonstrating promising application in the PEMWE industry.

A bridge damage monitoring and assessment strategy based on Gaussian mixture modelling

For the bridges equipped with health monitoring systems, it is essential to precisely assess the health status of the bridge from the data with noise and outliers. An improved Gaussian mixture model clustering algorithm is used to process the obtained bridge strain sensor monitoring data and generate the characteristic data of clustering in order to improve the accuracy of data analysis of bridge health monitoring system. The cluster and feature data are obtained by Expectation Maximization process, and the isolated clusters are filtered out by the threshold parameters of weight and the Euclidean distance between clusters center. Based on the feature data, a scoring strategy is established to assess the bridge health and sensor status. The proposed strategy is used to analyze the monitoring data of a bridge in western China, and the analysis results show the availability of this strategy. Compared with the directly collected data, the processed bridge health scoring curve variation is smooth, which can reduce the influence of noise and abnormal data. The sensor status scoring curve can track changes in collected data and respond to different transformation scenarios. This shows that the proposed strategy can evaluate the state of this bridge and the sensors. provided a reference for bridge maintenance decision during the operational period.

К проблеме неконтролируемой и нерегулируемой миграции как угрозе национальной безопасности России (на примере обеспечения на территории московского территориального гарнизона правопорядка и воинской дисциплины)

The article examines the problem of uncontrolled and unregulated migration processes in modern Russia, leading to problems with ensuring national security (using the example of ensuring law and order and military discipline on the territory of the Moscow territorial garrison). The article emphasizes the importance of maintaining controllability of migration processes, since an uncontrolled influx of migrants can cause an increase in ethnic crime, social and religious conflicts. At the same time, the importance of strengthening civil unity, all-Russian civic identity, interethnic and interfaith harmony, and preserving the identity of the multinational people of the Russian Federation during the period of a special military operation was noted.

Facile preparation of superhydrophobic PVDF/MWCNTs distillation membranes: Synthesis, characteristics and separation performance

In recent years, membrane distillation (MD) has emerged as an effective solution to mitigate the high energy consumption associated with conventional fermentable sugar concentration processes. However, the inherent low mechanical strength of traditional organic membrane surfaces can result in issues related to membrane wetting during long-term MD experiments. In this work, superhydrophobic PVDF/MWCNTs (multi-walled carbon nanotubes) distillation membranes with high mechanical strength were prepared by a combination of templating and co-blending techniques. The process involved peeling the semi-gelation membrane from a sandpaper template, subsequently forming a high aspect ratio microstructure on the membrane surface via tearing and pulling. Additionally, the incorporation of MWCNTs further bolstered the mechanical strength of the membrane. At a peeling time of 90 s and a MWCNTs content of 0.08 wt%, the distillation membrane exhibited an impressive water contact angle of 153.2°, indicating it possess exceptional hydrophobicity while maintaining high mechanical strength. The separation performance of the prepared distillation membranes has been inspected by conducting both experimental analyses and computational fluid dynamics (CFD) modeling of the entire MD process. An appropriate elevation in both feed flow rate and temperature could effectively mitigate the problem of temperature and concentration polarization on the membrane surface. PVDF/MWCNTs distillation membrane demonstrated a modest reduction in permeate flux of about 11.69 % and a stable rejection rate exceeding 99.95 % throughout a 100-hour operational period, and it required only 15 h to concentration of aqueous glucose solution to 100 g/L, significantly enhancing the efficiency of the process. This study also employed a combination of experiments and simulations to optimizes the process conditions guiding the vacuum membrane distillation (VMD) process and could provide guidance for the future application of membrane distillation in the concentration of sugar solutions.

Performance, kinetic characteristics and bacterial community of short-cut nitrification and denitrification system at different ferrous ion conditions.

In order to explore the operation performance, kinetic characteristics and bacterial community of the short-cut nitrification and denitrification (SND) system, the SND system with pre-cultured short cut nitrification and denitrification sludge was established and operated under different ferrous ion (Fe (II)) conditions. Experimental results showed that the average NH4+-N removal efficiency (ARE) of SND system was 97.3% on Day 5 and maintained a high level of 94.9% ± 1.3% for a long operation period. When the influent Fe(II) concentration increased from 2.3to 7.3 mg L-1, the sedimentation performance, sludge concentration and organic matter removal performance were improved. However, higher Fe(II) of 12.3 mg L-1 decreased the removal of nitrogen and CODCr with the relative abundance (RA) of Proteobacteria and Bacteroidetes decreased to 30.28% and 19.41%, respectively. Proteobacteria, Bacteroidetes and Firmicutes were the dominant phyla in SND system. Higher Fe(II) level of 12.3 mg L-1 increase the RA of denitrifying genus Trichococcus (33.93%), and the denitrifying genus Thauera and Tolumonas dominant at Fe(II) level of no more than 7.3 mg L-1.

Enhanced interfacial evaporation of CF@NC fabric via coupled photo-thermal and Joule-heating effect

To address the challenges of global water pollution and scarcity, solar-driven interfacial water evaporation has emerged as a viable method for producing clean water. Nevertheless, the efficacy of most extant interfacial evaporation systems were contingent upon abundant sunlight, thereby constraining their utility. To surmount the limitation, this study introduced a coupled tunable photo-thermal and Joule-heating process for interfacial evaporation utilizing carbon fiber (CF) modified by N-doped carbon nanotubes (NC). The CF@NC had highly graphitized structure, excellent light-absorbing ability and hydrophilicity, which made it suitable for photo-thermal and Joule-heating conversion. Under the coupled effect of photo-thermal and Joule-heating, the evaporation rate reached 10.37 kg·m−2·h−1 with 1 sun and 2.5 V, while the rate was 1.81 kg·m−2·h−1 under only 1 sun and 7.63 kg·m−2·h−1 with 2.5 V. Meanwhile, the CF@NC fabric evaporator also showed promising potential in salt tolerance and dye wastewater treatment. Under continuous all-day operation, a superior purification performance was achieved, which realized long periods of no salt operation and effectively remove the Rhodamine B and methyl orange in the water. Considering the high evaporation rate and reliable water yields obtained from simulated seawater and dye wastewater, the CF@NC fabric evaporator hold great promise for highly efficient purification.

Impact of Pseudo-Stochastic Pulse and Phase Center Variation on Precision Orbit Determination of Haiyang-2A from Experimental HY2 Receiver GPS Data

Haiyang-2A (HY-2A) is the first marine dynamic environment satellite established by China, which has made significant contributions to the marine scientific research field. It carries the satellite-based GPS receiver named HY2, which was independently developed by China. It is an experimental satellite-borne GPS receiver for low earth orbit satellites, and during its operational period in orbit, the satellite-borne GPS data are not made accessible to the public. Therefore, this paper assesses the quality of HY-2A satellite-borne GPS data based on indicators such as satellite visibility, multipath effect, and ionospheric delay. The results indicate that the data acquired by the HY2 receiver are of high quality. The precise orbit determination (POD) uses the reduced-dynamic (RD) method. The adjustment effects of the pseudo-stochastic pulse time interval and a priori sigma on POD are analyzed, and the antenna phase center variation (PCV) is estimated using the direct method and residual method. Furthermore, this paper investigates the impact of PCV models with different resolutions (10° × 10° and 5° × 5°) on satellite orbit determination. To evaluate the orbit precision, three methods are used for validation, including carrier phase residual analysis, external precise science orbit (PSO) validation, and SLR three-dimensional (3D) validation, respectively. The results indicate that the highest orbit precision is achieved when the pseudo-stochastic pulse time interval is configured to 15 min, with the a priori sigma of 1 × 10−8 m/s2. The orbit carrier phase residuals reach the millimeter level. The 10° × 10°PCV model was estimated using the direct method and residual method, respectively; the root mean square of the external orbit validation for both methods show a millimeter-level improvement. The results obtained from the direct method and residual method are comparable. The resolution is increased from 10° to 5°, and the improvement in orbital precision is relatively small. The results obtained from the SLR 3D validation are consistent with those from the external PSO validation. The experimental results contribute valuable information for the POD of the HY2 series satellites.

Influence of vegetation and substrate type on removal of emerging organic contaminants and microbial dynamics in horizontal subsurface constructed wetlands

Constructed wetlands (CWs) offer an efficient alternative technology for removing emerging organic contaminants (EOCs) from wastewater. Optimizing CW performance requires understanding the impact of CW configuration on EOC removal and microbial community dynamics. This study investigated EOC removal and microbial communities in horizontal subsurface flow (HSSF) CWs over a 26-month operational period. Comparison between tuff-filled and gravel-filled CWs highlighted the superior EOC removal in tuff-filled CWs during extended operation, likely caused by the larger surface area of the tuff substrate fostering microbial growth, sorption, and biodegradation. Removal of partially positively charged EOCs, like atenolol (29–98 %) and fexofenadine (21–87 %), remained constant in the different CWs, and was mainly attributed to sorption. In contrast, removal rates for polar non-sorbing compounds, including diclofenac (3–64 %), acyclovir (9–85 %), and artificial sweeteners acesulfame (5–60 %) and saccharin (1–48 %), seemed to increase over time due to enhanced biodegradation. The presence of vegetation and different planting methods (single vs. mixed plantation) had a limited impact, underscoring the dominance of substrate type in the CW performance. Microbial community analysis identified two stages: a startup phase (1–7 months) and a maturation phase (19–26 months). During this transition, highly diverse communities dominated by specific species in the early stages gave way to more evenly distributed and relatively stable communities. Proteobacteria and Bacteroidetes remained dominant throughout. Alphaproteobacteria, Acidobacteria, Planctomycetes, Salinimicrobium, and Sphingomonas were enriched during the maturation phase, potentially serving as bioindicators for EOC removal. In conclusion, this study emphasizes the pivotal role of substrate type and maturation in the removal of EOCs in HSSF CW, considering the complex interplay with EOC physicochemical properties. Insights into microbial community dynamics underscore the importance of taxonomic and functional diversity in assessing CW effectiveness. This knowledge aids in optimizing HSSF CWs for sustainable wastewater treatment, EOC removal, and ecological risk assessment, ultimately contributing to environmental protection.

Haemodynamic responses to intubation, extubation and post‐operative analgesia after intravenous lignocaine in laparoscopic cholecystectomy surgeries: a randomized control study

ABSTRACT:
 Objectives: To evaluate the effect of intravenous lignocaine on haemodynamic responses to intubation, extubation and post‐operative analgesia in laparoscopic cholecystectomy surgeries.
 Methods: This prospective, randomized, double blinded study was conducted in patients for elective laparoscopic cholecystectomy surgery in tertiary care hospital of Tamil Nadu. Group A (n=60) received 0.9% normal saline for perioperative intravenous infusion and Group B (n=60) received preservative free lignocaine 2% (20mg/ml) as intravenous infusion Hemodynamic responses were recorded to intubation, extubation and post‐operative analgesia in both groups. VAS scores and pain free period were also compared.
 Results: Pulse rate (PR) and mean arterial pressure (MAP) were significantly increased in both the groups during laryngoscopy and intubation, though the rise of both in lignocaine group was significantly less than normal saline group. (p<0.0001) Similarly, both PR and MAP were significantly increased during extubation in both the groups. (p<0.0001) However, the rise of both the parameters in lignocaine group was significantly less as compared to normal saline group. (p<0.0001) VAS scores in immediate post operative period were better in lignocaine group than normal saline group. The mean pain free period was less than an hour in normal saline group, while it was approximately 4 hours in lignocaine group. (p<0.0001)
 Conclusions: This study concluded that i.v infusion of lignocaine had significantly increased the pain free period post operatively. So those who are not affordable for epidural block, lignocaine i.v infusion is better alternative for post operative analgesia.

A mass and energy balance for a specific refuelling of Angra 2 nuclear power plant from a life cycle perspective

This work presents a detailed analytical balance of the material and energy flows associated with the nuclear fuel dynamics of the Angra 2 nuclear power plant (Brazil). A model is proposed for tabulation of material and energy flows, applied to each life stage of the nuclear fuel cycle, from extraction of raw material and production of nuclear fuel to post-use of fuel assemblies (FAs), when these are transformed into nuclear tailings. The tabulated and systematized data refer to the plant operation over a full load period. Approximately one year is the period of the plant operation after a regular refuelling and, at this period, all the materials and energy inputs are considered in addition to the wastes generated by the nuclear fuel cycle, including the ones due to operation and maintenance of the power plant in that period. Since 1/3 of the FAs of the core are replaced by fresh FAs, this analysis considers energy and material flows related to the production of fresh FAs. Related to these processes, it is taken into account what follows: 1) Uranium mining and processing, 2) Conversion of uranium concentrate into uranium hexafluoride (UF6), 3) Uranium (UF6) enrichment, 4) reconversion of the enriched UF6 to uranium dioxide (UO2), 5) Production of nuclear fuel - from the pellets to FAs, 6) Power generation from plant operation, and 7) Generation and management of nuclear tailings arising from the regular operation of the plant in that period. The analysis of systematized data from the various stages of the cycle allows a broader analysis and the perception of critical aspects, such as the need for technological improvements, logistical advances, care for the environment and public health, increased energy efficiency, in addition to the need for materials recycling, among other possibilities.

AN INVESTIGATION ON THE CAUSES OF CORROSION IN AISI 1009 STEEL PIPE OF THE FIRE LINE IN THE GAS REFINERY

In view of several reported cases of cracking in the piping of the fire extinguishing sector in the oil tanks, a detailed identification of the failure mechanisms was required for the safe continuation of gas processing. Therefore, this study investigated the damage of steel fire extinguishing pipes after a certain period of operation. Severe thinning of the wall thickness was observed in two parts of the pipe. Comprehensive analytical investigations, including optical microscope (OM), quantometer, XRD, FE-SEEM, EDS and microhardness were performed. In addition, the corrosion behavior of the material was investigated by polarization and EIS analysis and the most plausible reactions and corrosion mechanisms were elucidated. The corrosion products on the inside of the pipe included oxide compounds, while on the outside, it was mainly sulfides and oxides. A drastic and slight decrease in microhardness was observed near the inner and outer surfaces, respectively. Electrochemical tests proved the formation of a porous and non-protective layer of corrosion products. The corrosion resistance was found to be weak due to several factors: the nature of the AISI-1009 steel, several micropores, the periodic formation and removal of non-continuous oxide layers and the roughness that accelerated the strong thickness reduction.

Introducing a tailored site delineation approach to optimize the design of managed aquifer recharge surface spreading infrastructure

Managed aquifer recharge (MAR) is an emerging solution to effectively replenish overused groundwater resources, but high associated costs often hinder its uptake. There are several parameters to consider when determining the cost of MAR, including recharge types, scale of MAR schemes, land acquisition, operation and maintenance period, and the hydrogeological setting. Hydraulic conductivity and its spatial variability are the most significant hydrogeological parameters for predicting infiltration rates at MAR sites, but limited data availability makes accurate predictions often challenging. Hence, it is essential to increase data availability to optimize MAR efficiency and to better assess its economic performance. Therefore, a novel approach for MAR planning is presented in this article to efficiently enhance the data availability during the conceptual stage of MAR planning by combining site exploration, spatially resolved infiltration rate estimation, and cost analysis. The approach was applied at an actual MAR site in Vincenza, Italy, and incorporated an electromagnetic induction survey and direct push profiling as across-scale investigation methods to enhance site delineation and subsequent parameterization of the identified zones using laboratory analysis of collected samples. This MAR site is particularly suitable for its heterogeneous subsurface structure and potential to counteract groundwater depletion. The performed investigation resulted in an image of the lateral variation of subsurface conditions and allowed the delineation of three zones with different infiltration behavior, with 99.5% of infiltration occurring in just two zones, representing only 22.1% of the site. In this particular scenario, the overall cost per cubic meter of recharged water can be reduced by 59.1% by identifying and eliminating unfavorable zones. This study provides scientists and practitioners with a useful tool for MAR planning that can be applied to a wide range of sites with complex geology, thereby reducing water costs, minimizing the environmental impact of infrastructure construction, and reducing land use conflicts.

Numerical study of soil heat and moisture migration in seasonal ground heat storage

Heat and moisture transfer is an important factor leading to soil drying shrinkage and heat transfer attenuation in the process of seasonal soil heat storage with high temperature. The purpose of this study is to establish a numerical model to explore the characteristic of heat and moisture migration in heat storage soil. The numerical model is verified by the experimental data. In this study, two months heat storage with high-temperature (80℃) and five months heat extraction with low-temperature (20℃) seasonal operation period was simulated, and the changes in the temperature and moisture content of the heat storage soil were analyzed. After a seasonal period, the mean temperature in the backfill and the original soil would increase. The moisture content in original soil would increase, while the moisture content in the backfill would decrease. For the typical backfill with 0.4 m diameter, the obvious heat and moisture migration phenomenon only occurs in the backfill and the part of the original soil close to the backfill.

Deep dynamic high-order graph convolutional network for wear fault diagnosis of hydrodynamic mechanical seal

The hydrodynamic mechanical seal (HDMS) in the reactor coolant pump of third-generation nuclear power units is vulnerable to failure due to prolonged operational periods and inevitable wear. However, traditional fault diagnosis methods are not robust to noise and can not leverage both the topological relationships among samples and local features. To resolve these challenges, in this paper, we propose a novel graph convolutional network (GCN) for wear fault diagnosis of HDMS called deep dynamic high-order graph convolutional network (DDHGCN). A dynamic graph learning module is designed to control the connectivity and sparsity of the iterated graph and thus eliminate errors and redundancies caused by noise. A high-order GCN module is proposed to effectively model the correlations between nodes, capturing contextual information and mutual influences among them. A residual convolutional module is applied to extract local features hidden in individual samples to further improve the classification performance. All three modules are jointly optimized for reliable wear fault diagnosis of HDMS. Experimental results demonstrate that our DDHGCN can achieve higher performance when compared with the state-of-the-arts.

An Observational Study on Port-site Infection and its Management in Patients Undergoing Laparoscopic Cholecystectomy

Background: With increasing number of performed laparoscopic cholecystectomies, there is an increasing number ,of port site infection, although it occurs infrequently, but it has significant influence on overall outcomes of laparoscopic cholecystectomy. The aims of the present study was to identify the causative organism involved in port-site infection (PSI) and its management and outcome after laparoscopic cholecystectomy objectives and to evaluate causative organism involved in port site infection after laparoscopic cholecystectomy.Materials & Methods: Patients who underwent laparoscopic cholecystectomy and now presenting with PSIin General Surgery OPD and Emergency of Burdwan Medical College and Hospital. Thorough clinical historytaking followed by swabs was taken for culture and sensitivity in all patients who developed port site infection after laparoscopic cholecystectomy. Tissue samples were taken for detection of mycobacterium tuberculosis by CBNAAT. All patients were followed up for 6 months post operatively. Incidence of PSI in relation to gender, pre-operative diagnosis, spillage, relation with different port sites and the type of microorganism associated was evaluated and compared with previous study.Results: In the present study 90 patients who underwent laparoscopic cholecystectomy, 19 patients reported port site infection after surgery, whereas the remaining 71 patients had uneventful post operative period. Out of the 19 infected 7 were male [25% of total male cases] and 12 were female [19% of total female cases]. Cases of port site infection were 21% of total cases. Conclusion: The incidence of PSI was higher in cases of acutely inflamed GB, biliary spillage, open port creation, avoidance of endo-bag, and in comorbidities. They were managed with either antibiotics, dressing or surgical exploration.

Construction of graphene oxide intercalated with UiO-66-PEI heterostructure membrane for efficient pervaporation dehydration of isopropanol

The separation of isopropanol (IPA)-water mixtures is a critical process in chemical, bioprocess, and electronics industries. This study aims to develop a high-performance pervaporation (PV) membrane for IPA-water separation through incorporating UiO-66-PEI into graphene oxide (GO) membrane by leveraging the combined properties of 2D and 3D nanomaterials. Polyethyleneimine (PEI) was grafted into UiO-66-NH2 to synthesize UiO-66-PEI using Schiff base reactions with glutaraldehyde. The UiO-66-PEI was subsequently intercalated into GO layers to fabricate the membrane in hydrolyzed polyacrylonitrile support using pressure filtration. This intercalation significantly impacted the chemical properties and structure of the GO, leading to an enhanced PV performance in IPA-water mixture separation. The resulting membrane demonstrated a remarkable separation efficiency with a permeation flux of 1479 g∙m−2∙h−1 and a high water content in the permeate of 99.60 wt%. Notably, the exceptional separation performance of the nanocomposite membranes was sustained across varying feed concentrations, operating temperatures, and during long-term operational periods. The findings in this work offer valuable insights into the fabrication of GO-based heterostructure membranes with significant implications for advancing PV separation technology.

Determination of volume of radioactive waste in activated VVER-1200 reactor structures

The results of calculation studies of the amount of solid high-level, intermediate-level, low-level, very lowlevel radioactive waste (HLW, ILW, LLW, VLLW, respectively) generated during neutron activation of structural materials adjacent to the core of the VVER-1200 reactor plant, depending on the time after the final stopping it. An assessment of the volumes of radioactive waste (RAW) of activation origin generated over 60 years of operation of a VVER-1200 type reactor was carried out on the basis of computational studies of the induced activity of structural and protective materials using reactor and Monte Carlo program codes (SERPENT 2, TVS-M, DYN3D , MCU-PD). Specific activities for each isotope, total specific activities and activities, masses and volumes of activated structural and protective reactor materials for various categories of radioactive waste were calculated after the specified period of operation of VVER-1200 and over time after the final shutdown of the reactor. The obtained dependences of changes in the masses and volumes of activated materials over time after the final shutdown of the reactor make it possible to determine these parameters of materials separately for each category of radioactive waste and in total at any point in time. Thus, the masses of activated materials related to radioactive waste will decrease by 264 tons (from 713 to 449 tons) over 200 years of aging, and the volumes will decrease by 74.3 m3 (from 169 to 94.7 m3). Forecast quantitative data on the volumes and mass of activated reactor structures, depending on the duration of their exposure after the final shutdown of the power unit, will make it possible to develop technical proposals, forecast plans and schedules for organizing a radioactive waste management system during the decommissioning of the VVER-1200 reactor plant, as well as possible technological and design solutions for the disposal system for these radioactive waste.

Prediction model for high arch dam stress during the operation period using LightGBM with MSSA and SHAP

Dam stress is an important physical quantity to assess high arch dam safety during the operation period. To address the issues of low prediction capability and poor interpretability for high arch dam stress, a prediction model for high arch dam stress during the operation period incorporating the multi-strategy sparrow search algorithm (MSSA), light gradient boosting machine (LightGBM) and Shapley additive explanation (SHAP) is proposed utilizing the measurement data from the dam. First, the initial population diversity and quality of sparrows are improved by using Tent chaotic mapping and refractive inverse learning strategy, and the global search ability of the sparrow search algorithm (SSA) is enhanced by making sparrows jump out of local optimal positions based on adaptive t-distribution mutation. Second, the MSSA conducts optimization analysis on the LightGBM model, effectively solving the issue of the machine learning algorithm converging to local optimal solutions and enabling the determination of optimal hyperparameters. Finally, SHAP is introduced to enhance the interpretability of the MSSA-LightGBM model. The performance measurement indicates that the MSSA, which combines several excellent methods, outperforms SSA and particle swarm algorithm (PSO) in terms of global search ability. The MSSA-LightGBM dam stress model exhibits superior prediction precision compared to the SSA-LightGBM, PSO-LightGBM, LightGBM, and extreme gradient boosting models. SHAP can enhance the interpretability of the MSSA-LightGBM model and identify the crucial features affecting high arch dam stress. This research is highly significant in enhancing the prediction and analysis capabilities of high arch dam stress.

Study on the effect and regularity of plating parts cleaning wastewater by enhanced aerobic process with high-density bacterial flora

In this research, we established an enhanced aerobic biological method utilizing a high-density bacterial flora for the treatment of low-biochemical plating parts washing wastewater. The elucidation of pollutant removal mechanisms was achieved through a comprehensive analysis of changes in sludge characteristics and bacterial community structure. The results demonstrated that throughout the operational period, the organic load remained stable within the range of 0.01–0.02 kgCOD/kgMLSS·d, the BOD5/COD ratio increased from 0.004 mg/L to 0.33 mg/L, and the average removal rates for key pollutants, including COD, NH4+-N, and TN, reached 98.13%, 99.86%, and 98.09%. MLSS concentration remained at 7627 mg/L, indicating a high-density flora. Notably, Proteobacteria, Bacteroidota, and Acidobacteriota, which have the ability to degrade large organic molecules, had been found in the system. This study affirms the efficacy of the intensive aerobic biological method for treating low-biochemical plating washing wastewater while ensuring system stability.

Inferior alveolar nerve block anesthesia in children: The effect of ibuprofen and phentolamine mesylate on pain perception.

For successfully managing pediatric dental patients, local anesthesia is essential to eliminate pain during or after the operative period. An early recovery from soft-tissue anesthesia after an inferior alveolar nerve block (IANB) should benefit a young child patient by avoiding the risk of inadvertently biting the soft tissues. Hence, the purpose of the study was to (1) evaluate and compare the efficacy of pre- and postoperative ibuprofen on pain perception in children who undergo IANB anesthesia with or without the use of PM and (2) evaluate the average time required for reversal of anesthesia symptoms using phentolamine mesylate. The present study was a randomized, clinical trial performed among 60 children between 6 and 8 years of age using a convenient sampling method. The children were randomly assigned into four equal groups of 15 each using the computer-generated randomization sequence. IANB anesthesia was performed using 2% lignocaine with 1:100,000 epinephrine, and a mandibular primary molar pulpotomy was performed on each group. Group 1: the ibuprofen tablet was taken 1 h before the onset of the procedure. Group 2: ibuprofen tablet 30 min after the pulpotomy procedure. Group 3: the ibuprofen tablet was taken 1 h before the onset of the procedure, and the Phentolamine mesylate (PM) injection was administered. Group 4: immediately after the pulpotomy, the PM injection was administered, and an ibuprofen tablet was taken 30 min after the pulpotomy procedure. All children were assessed for the duration of soft-tissue anesthesia, their behavior scores and pain rating, as well as the incidence of postoperative self-inflicted injuries. A one-way ANOVA was used to compare the average time needed for the reversal of anesthetic symptoms between groups. The effects of phentolamine, local anesthetics, and ibuprofen on the child's behavior and pain scores were compared using the Student's t-test. For the study, P < 0.05 was accepted as statistically significant. The time needed for the full reversal of anesthetic symptoms to manifest on the tongue and lip was substantially reduced by the injection of phentolamine (P < 0.001). The use of phentolamine for reversal or the intake of ibuprofen pre- or postoperatively did not exhibit any significant variation in the behavior, pain experience, or incidence of self-inflicted injuries in the child. It is evident that although phentolamine injections shorten the duration of anesthesia, the adjunctive use of pre- or postoperative ibuprofen did not significantly alter pain scores.