Residual Levels Research Articles

Styrene Migration from Polystyrene for Food Contact: A Case Study on the Processing Chain of Yoghurt Pots

A precautionary specific migration limit of 40 µg/kg for styrene from food contact materials is currently under evaluation in Europe. In the ongoing discussion about applicable methods to demonstrate compliance, testing with food instead of simulants or total transfer calculations has been proposed. In this study, the residual styrene levels in high-impact polystyrene (HIPS) blended with general-purpose polystyrene (GPPS) were determined at several levels of the processing chain of yoghurt pots (from pellets to sheets, then to pots). The styrene migration from extruded sheets and thermoformed pots was analyzed in food simulants at 10 days/20 °C and 40 °C, as well as in yoghurt after storage at 8 °C after 50 days. The obtained results show that the residual styrene content in the PS materials correlates with migration. However, the migration of styrene was far below the total transfer assumption. Styrene migration from the sheets into food simulants and into yoghurt exceeded that migrating from the pots. Styrene migration into food simulants in 20% ethanol at 10 days/20 °C and 40 °C and, more clearly, in 50% ethanol at 10 days/40 °C, was higher than that into yoghurt tested on the best-before date. Styrene migration from PS pots into yoghurt after storage at 8 °C for 50 days reached up to 15 µg/kg (applying the EU cube model), which would be conservatively covered by testing the PS pots with 20% ethanol at 10 days/20 °C.

Regulatory Effects of Chlormequat Chloride on the Yield and Chemical Composition of Angelica sinensis Radix

Chlormequat chloride (CCC), as a commonly used plant growth regulator in the production of rhizomatous medicinal herbs, can effectively control the bolting phenomenon in Angelica sinensis, significantly increasing the yield of underground rhizomes (medicinal part). However, its specific effects on the intrinsic quality of Angelica sinensis, especially medicinal components, require further investigation. The objective of this study is to conduct a thorough examination of CCC residue and its influence on the yield and medicinal components of Angelica sinensis. By spraying different concentrations of CCC on Angelica sinensis, we systematically monitored the final yield of Angelica sinensis Radix (ASR) in each treatment group and the residual concentration of CCC in ASR. Using UPLC-QTOF-MS technology, we conducted an in-depth analysis of the metabolic profile of ASR. Subsequently, UFLC-MS/MS was employed to accurately quantify the changes in the content of nine key active components in ASR. The results of this study indicate that the application of CCC significantly improves the yield of ASR, with the best effect observed at 0.1 g/L, resulting in a yield increase of 24.8%. Meanwhile, the residual amount of CCC in ASR is positively correlated with the application concentration, with the residual levels as high as 7.12 mg/kg in the high-concentration treatment group. Metabolomic analysis preliminarily identified 21 chemical components in ASR, including four organic acids and 13 phthalides. It is worth noting that the quantitative analysis results indicate significant changes in active components such as butylphthalide, Z-ligustilide, and ferulic acid after the application of CCC. Specifically, high-concentration CCC significantly increased the content of butylphthalide and levistolide A, while low-concentration CCC significantly promoted the accumulation of coniferyl ferulate and senkyunolide A, accompanied by a significant decrease in Z-ligustilide and ferulic acidy. In conclusion, while CCC use can increase yield, the associated increase in residues and imbalanced composition ratios may threaten the quality and safety of ASR. Therefore, it is crucial to control the amount of CCC used rationally to balance yield enhancement and quality assurance.

Levels of organochlorine pesticides in the chewable and leftover parts of the khat (Catha edulis) sold in local markets of Jimma Town, Southwest Ethiopia

ABSTRACT This study aimed to determine the residual levels of organochlorine pesticides (OCPs) in chewable (tender leaves) and leftovers (mature leaves) of khat sold in local markets in Jimma town, southwest Ethiopia. Samples were collected from various local khat market places in Jimma town, based on their growing origin. A modified QuEChERS method was used to extract pesticides from the samples before their analysis by GC‒MS. The findings indicated that p,p’-dichlorodiphenyldichloroethylene (p,p’-DDE) and p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT) were detected in 88.3% and 76.6% of chewable samples, and in 86% and 69% of khat leftovers samples. The p,p’-DDE and p,p’-DDT levels found in chewable khat ranged from 10.12–45.39 and 8.53–34.15 µg/kg, respectively. While in leftover khat they ranged from 30.12–45.04 and 6.73–32.16 µg/kg, respectively. It was found that the concentration of p,p’-DDE is greater than its precursor compound p,p’-DDT for each sample, indicating past use of DDT in the study area. None of the detected analytes exceeded the maximum residue level (MRL) values established by the FAO/WHO or European Commission (EC) of 50 µg/kg. However, no information is available regarding these pesticides’ collective and synergetic negative impacts on consumers.

Effectiveness of three treatment methods on melanosis inhibition and SO2 residual concentration in pink shrimps (Parapenaeus Longirostris) after various sulphite-based treatments in Morocco

ABSTRACT Melanosis in seafood is a natural post-mortem enzymatic process that results from the action of polyphenol oxidase from the animal’s own tissues. It reduces the organoleptic quality of the shrimp and their commercial value. This work concerns prevention of melanosis in pink shrimp (Parapenaeus longirostris) using the latest technology of enzymatic biosensor for sulphite detection. Three application methods (dipping, dusting, and spraying) with four commercial products were tested. Sulphite concentrations (1–3%) were applied for 1–10 min. Parameters measured included residual SO2 levels, pH, melanosis, and odour. Findings showed that the dusting method gave the best sensory scores, but had harmful residual SO2 values. The dipping method provided safe SO₂ levels below normative limits, when using products with 240 g Kg−1 SO₂ content applied at 1.25% bisulphite/seawater for 1 minute. Regarding the spraying method, the results remain promising. Nevertheless, further studies are necessary to understand its potential and limitations fully.

Influence of atmospheric state on variability of long-term residual ambient sound level measurements in a subalpine valley.

Two natural influences on the acoustic environments of mountainous parks and communities are flowing water and shifting weather. A central purpose of the acoustic measurement design used by the United States National Park Service is to provide spectral estimates of residual ambient sound level metrics at a seasonal time scale. Acoustic monitoring sampling methodologies are often designed using a sequence of similar measurements. When source and residual ambient spectra overlap, an estimate of variability in the latter is beneficial to successful monitoring design. The observed and modelled effects of atmospheric state on sound level are analyzed to reveal variability due to these effects at a long-term monitoring site in Denali National Park, Alaska. The analysis of variability incorporates a covariate that is otherwise challenging to estimate in remote settings: vertical temperature gradients in the atmospheric boundary layer. Results reveal inversions (positive gradients) in the atmosphere ≥30% between 19:00 and 09:00. Inversion strengths above 0.06 °C/m are associated with 10-15 dB increases in sound level over hourly time scales. Because inversions tend to occur during otherwise quiescent times of day, they ultimately reduce seasonal variability at the site and corresponding uncertainty in noise metrics for transportation noise arriving from varied directions.

Clinical implications of residual normal plasma cells within bone marrow across various disease stages in multiple myeloma.

Residual normal plasma cells (NPCs), which compete with tumor plasma cells, play an important role in multiple myeloma. However, large-scale cohort studies investigating residual NPCs, especially at the minimal residual disease (MRD) phase, are currently lacking. In this study, we conducted a comprehensive investigation into the clinical significance of residual NPCs throughout the entire disease course in 1363 myeloma patients from the NICHE cohort (NCT04645199). Our results revealed that myeloma patients with high baseline NPCs ratio (≥5%) exhibited distinct indolent features, characterized by lower tumor burden, reduced frequencies of cytopenia, immunoparesis, and high-risk cytogenetics. Importantly, high residual NPCs ratio at diagnosis or relapse was independently associated with favorable survival. High absolute percentages of NPCs at undetectable MRD were related with superior clinical benefit and immune reconstitution. At MRD-positive phases, grouping based on NPCs ratio (<50%, 50-90%, ≥90%) demonstrated better risk stratification compared to residual tumor log levels. Based on the time-dependent NPCs ratio trend, we developed a dynamic MRD model that classifies patients into three groups with diverse longitudinal trends, leading to distinct prognoses. Collectively, residual NPCs serves not only as a valuable complementary biomarker for risk stratification but also provides valuable insights on reclassifications and kinetics of MRD.

Effects of hot isostatic pressing on the micron-scale residual stress of nickel-based single-crystal superalloys

Quantifying the residual stress at micron-scale is crucial for comprehending the trans- and inter-granular deformation mechanisms and the influence of heat treatment, but remains technically challenging. This study utilized focused ion beam and digital image correlation (FIB-DIC) techniques to assess residual stress within the dendrite stem and arm of nickel-based single-crystal superalloys. The influence of hot isostatic pressing (HIP) on the microstructure and residual stress was also elucidated. Our results revealed that the residual stresses in the dendrite stem and arm regions manifest as tensile stress along the x-axis and compressive stress along the y-axis, with a range of -720 MPa to 680 MPa. HIP treatment effectively improved microstructure and regulated residual stress in nickel-based single-crystal superalloys, leading to a rapid reduction in residual stress levels. The present study lays a solid theoretical groundwork for optimizing processing strategies to regulate residual stress and enhance mechanical properties in next-generation single-crystal superalloys.

Asymptomatic Elevated Inflammatory Markers: Is There a Risk for Infection or Revision in Primary Total Knee Arthroplasty?

BackgroundTotal knee arthroplasty (TKA) is the treatment of choice for advanced knee osteoarthritis. Long-term studies report high patient satisfaction, while complications such as periprosthetic joint infection (PJI) can be devastating. Knowledge regarding risk factors for PJI is critical to minimize and ideally avoid complications. The purpose of this study was to investigate the risk of PJI and revision in patients who had preoperative asymptomatic high C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels in primary TKAs. MethodsPatients undergoing primary TKA between 2010 and 2022 were eligible. Inclusion criteria were patients who had preoperative complete biochemical parameters and a minimum follow-up of 12 months. Patients who died during the first year, and those who had a history of inflammatory arthritis, autoimmune disease, renal pathologies or septic arthritis, were excluded. Patients who had elevated blood CRP and ESR levels taken within 48 hours before surgery underwent a thorough medical examination with a focus on infection symptoms. After screening and consultation, residual elevated CRP and ESR levels were classified as asymptomatic. After exclusions, 1,528 patients were included. The mean age was 66 years (range, 35 to 92) and the mean follow-up time was 6.4 years (range, 1.6 to 12.3). ResultsThe rate of revision within one year after surgery was 1.6%, whereas the rate of revision in the first five years was 3.8%. The PJI rates for the 1st and 5th postoperative years were 1.7 and 2.9% respectively. Regression analysis did not show any of the potential variables to be a risk factor for revision or PJI. ConclusionAsymptomatic elevated acute-phase reactants are not a risk factor for periprosthetic joint infection or aseptic revision. At a mean follow-up of 6.4 years, overall survival was 96.7%, with only 2.2% of patients revised due to a PJI.

United Nations Goals for Child Welfare in Pakistan: An Analysis of Midpoint Agenda

The primary objective of this study was to examine Pakistan's child welfare policies and programs in light of the United Nations' goals for 2030. The study aims to examine Pakistan's performance in child-related SDGs (Sustainable Development Goals) and to compare it to its neighbors, Sri Lanka, Bangladesh, and India. As a 'Quant-Qual Cross-sectional Study,' the researchers reviewed a number of secondary data sources available through their websites. Along with these many sources of quantitative data, the researchers also obtained qualitative information (e.g., child policies, programs, legislation, plans of action, etc.). It was a halfway evaluation, named the "Midpoint Agenda," of what is to be achieved by 2030. The Midpoint Agenda was analyzed in May 2024, nearly halfway through the UN goals set in 2015. The analysis of data leads us to the conclusion that child welfare in Pakistan remains at a residual level after 77 years. The welfare personnel's justified attitude has made it clear that Pakistan's residual welfare is the result of insufficient public investment and poor governance. Urgent attention is also required to overhaul all child welfare programs and instruments.

Turbocharged DISI engine low-load performance improvement investigation through ozone seeding with residual gases and excess air charge dilution

The automotive industry has long prioritized the search for more efficient engines, driven by environmental concerns, fuel prices, and consumer demand for fuel-efficient vehicles. Various technologies and strategies are explored to enhance performance while reducing fuel consumption and emissions. Despite potential combustion stability issues, techniques like using lean mixtures or retaining exhaust gases are commonly employed. Ozone seeding has emerged as a combustion enhancer for internal combustion engines, particularly effective under lean mixtures or high residual gas levels, aiming to stabilize de-throttling conditions, minimize pumping losses, and enhance engine efficiency by enhancing the reactivity of the mixture through the release of radicals that facilitate fuel oxidation. This study investigates the impact of ozone addition on engine performance, emissions, and fuel consumption using a turbocharged SI vehicular engine on a dynamometer bench under different loads. Ozone was introduced to the engine intake using an ozone generator with compressed air, considering two mixture dilution strategies: fresh air and residual gases. Results show that ozone application, with Brazilian Gasoline Type C, induces autoignition of the end-gas under specific low-load, low-engine speed conditions. Up to 1000 ppm, ozone has no discernible impact on DISI engine operation under excess air dilution, maintaining performance equivalent to the baseline. For specific operating conditions with 3 and 4 bar BMEP, where ozone stabilizes combustion with higher residual gas fraction (RGF) percentages, there is a notable reduction in specific fuel consumption, suggesting a potential 1%–1.5% increase in brake efficiency. However, ozone seeding with high RGF percentages leads to a slight increase in CO emissions, elevated NOX emissions, and a tendency to reduce THC emissions up to a certain RGF limit.

AVALIAÇÃO FÍSICO-QUÍMICA E MICROBIOLÓGICA DAS ÁGUAS DE BEBEDOUROS DE COZINHAS DA ESCOLA CIEP-216 PREFEITO JUAREZ ANTUNES

The objective of this work was to evaluate the water quality used in the Ciep – 216 Prefeito Juarez Antunes school in the Vila Martins, in the municipality of Nova Iguaçu – RJ, in terms of physicochemical and microbiological parameters. This state school was selected for water collection at two points: kitchen faucets and drinking fountain for analysis and comparison of parameters such as total coliforms, heterotrophic bacteria and Escherichia coli, as well as color, pH, turbidity and residual chlorine level, ammonia, total alkalinity, hardness, iron, oxygen consumed. The results showed that the water used by the school for various purposes, such as food preparation, personal hygiene and thirst quenching, is within the standards established by the ministry of health, drinking water.

Mycovirus-Containing Aspergillus flavus Alters Transcription Factors in Normal and Acute Lymphoblastic Leukemia Cells.

Transcription factors control genes to maintain normal hemopoiesis, and dysregulation of some factors can lead to acute lymphoblastic leukemia (ALL). Mycoviruses are known to alter the genetics of their fungal host. The present study evaluates the effects of the products of a mycovirus-containing Aspergillus flavus (MCAF), isolated from the home of a patient with ALL, on certain transcription factors of normal and ALL cell lines. Our published studies have shown that ALL patients have antibodies to MCAF, and that exposure of the mononuclear leukocytes of patients in complete remission to its products, unlike controls, results in the re-development of genetic and cell surface phenotypes characteristic of ALL. For the present study, normal, pre-B, and B-cell leukemia cell lines were exposed to the culture of MCAF. Pre- and post-exposure levels of PAX5, Ikaros, and NF-κB were assessed. Exposure to MCAF resulted in apoptosis, cell cycle changes, and complete downregulation of all transcription factors in normal cell lines. In acute leukemia cell lines, cellular apoptosis and alterations in the cell cycle were also noted; however, while there was downregulation of all tested transcription factors, residual levels were retained. The noted alterations in the transcription factors caused by MCAF are novel findings. The possible role of MCAF in leukemogenesis needs to be further investigated. Mycovirus-containing Aspergillus flavus was initially isolated from a leukemia patient's home. Our prior published studies have illuminated intriguing associations of this organism with leukemia. Unlike controls, patients diagnosed with acute lymphoblastic leukemia (ALL) harbor antibodies to this organism. Furthermore, the exposure of mononuclear cells from patients with ALL in complete remission to the products of this organism reproduced genetic and cell phenotypes characteristic of ALL. These findings underscore the potential role of environmental factors in leukemogenesis and hint at novel avenues for therapeutic intervention and preventive strategies.

Impact of elevated direct factor Xa inhibitor plasma levels on perioperative blood loss in patients undergoing urgent surgery.

Data on the perioperative bleeding risk associated with elevated plasma levels of direct factor Xa inhibitors (FXa inhibitors) are limited. This study examines perioperative red blood cell (RBC) loss in patients undergoing urgent surgery with a residual FXa inhibitor level exceeding 100 mcg/L and without preoperative FXa inhibitor reversal. This retrospective analysis includes data from 32 patients who underwent urgent noncardiac surgery between 2018 and 2022. This study aims to analyze perioperative RBC loss in patients undergoing urgent surgery with a residual FXa inhibitor level exceeding 100 mcg/L and without preoperative FXa inhibitor antidote-based reversal or unspecific treatment with 4-factor prothrombin complex concentrate (PCC). All patients were managed using a watch-and-wait strategy. The last determination of FXa inhibitor plasma concentration prior to surgery showed a median of 245 mcg/L (IQR 144-345), with a median time interval of 3.8 h (IQR 2.4-7.2) before incision. Median RBC loss during surgery was 49 mL (IQR 0-253), 189 mL (IQR 104-217) until POD1 and 254 mL (IQR 58-265) until POD3. Only one patient required intraoperative treatment with 4-factor-PCC and none required reversal with andexanet alfa. Linear regression models found no significant influence of FXa inhibitor plasma levels on intraoperative RBC loss. Rivaroxaban was associated with higher RBC loss until postoperative Day 1 compared with apixaban. No thromboembolic events were observed. Despite markedly elevated plasma concentrations of residual direct FXa inhibitors, perioperative RBC loss was limited in patients undergoing urgent noncardiac surgery. The intraoperative watch-and-wait strategy with selective intraoperative FXa inhibitor reversal or treatment only when required appears to be an appropriate approach.

Prediction of radiotherapy toxicity: 20 years of COPERNIC radiosensitivity diagnosis procedure

PurposeSince 2004, in the frame of the care pathway, our Research Unit has replied to the demand of expertise of radiation oncologists about the individual radiosensitivity of some of their patients. This procedure, called COPERNIC, is based on a skin biopsy and the radiation-induced nucleoshuttling of the ATM protein (the RIANS model), a major actor of DNA break repair and signaling. In 2016, with the first 117COPERNIC fibroblast lines, we obtained a significant correlation between the maximum number of the nuclear ATM foci, pATMmax, and the CTCAE severity grade of the post-radiotherapy tissue reactions. In this study, we propose to verify the validity of our previous findings with a new COPERNIC data subset obtained in the 2014–2024 period. Materials and methodsWe applied a standard immunofluorescence technique to quiescent COPERNIC fibroblasts to assess, after 2Gy, the level of micronuclei, γH2AX and pATM foci. The 117 COPERNIC data published in 2016 were considered as the reference data subset. A new COPERNIC data subset composed of 133fibroblast cell lines was considered as the validating data subset. ResultsOur data showed that spontaneous or residual micronuclei levels, and residual γH2AX foci levels cannot predict CTCAE grades. Conversely, the linear formula linking the maximal number of pATM foci and the corresponding CTCAE grade and obtained in 2016 from the reference data subset fitted well the validating data. ConclusionsThe maximal number of pATM foci appears to be one of the most reliable biomarkers for predicting post-radiotherapy radiotoxicity.

Forecast of Foreground Cleaning Strategies for AliCPT-1

We report the test results of several independent foreground cleaning pipelines used in the Ali CMB Polarization Telescope experiment (AliCPT-1), a high-altitude cosmic microwave background (CMB) imager in the Northern Hemisphere with thousands of detectors dedicated to the search for a primordial CMB polarization B-mode signature. Based on simulated data from four detector modules and a single season of observation, which we refer to as Data Challenge 1 (DC1), we employ different and independent pipelines to examine the robustness and effectiveness of estimates on foreground parameters and primordial B-mode detection. The foreground cleaning strategies used in the pipelines include the parametric method of template fitting (TF) and the nonparametric methods of constrained internal linear combination (cILC), analytical blind separation (ABS), and generalized least squares (GLS). We examine the impact of possible foreground residuals on the estimate of the CMB tensor-to-scalar ratio (r) for each pipeline by changing the contamination components in the simulated maps and varying the foreground models and sky patches for various tests. According to the DC1 data with the simulation input value r true = 0.023, the foreground residual contamination levels in the TF/ABS/cILC/GLS pipelines are well within the corresponding statistical errors at the 2σ level. Furthermore, by utilizing the tension estimator, which helps identify significant residual foreground contamination in the detection of the primordial B-mode signal by quantifying the discrepancy between various r measurements, we conclude that the presence of small foreground residuals does not lead to any significant inconsistency in the estimation of r.

Numerical Modeling of Extreme Sea Levels on the Laptev Sea Coast

The present study is devoted to the analysis of extreme sea level oscillations of the Laptev Sea using the ADCIRC model. The numerical modeling is performed on a high-resolution grid and verified for sea level observations from three tide gauges. We have revealed regional characteristics of extreme sea level oscillations for different parts of the Laptev Sea coast. The maximum total sea level range was 544 cm in Ebelyakh Bay, while the minimum was 267 cm in Khatanga Bay, where maximum tidal ranges were obtained. Some areas in Khatanga Bay and Anabar Bay had maximum tidal ranges exceeding 200 cm. The study provided an estimation of the possible magnitude of coastal flooding by calculating the extreme total and residual sea levels for different return periods: 1, 2, 5, 10, 20, 50, and 100 years. The amplitude of extreme surges calculated for the 100-year return period can exceed 300 cm for several sections of the Laptev Sea coast, with the maximum sea level range being about 680 cm for Anabar and Ebelyakh Bays.

Study of thermoluminescence characteristics of quartz for high radiation doses (>1kGy): Implications for extending the luminescence dating range

Quartz is an omnipresent abundant natural mineral, used for luminescence dating. Lately, quartz optically stimulated luminescence (OSL) technique is widely used to estimate the equivalent doses (De) for dating geological events (up to 250 Gy, limited by saturation). Some works report thermoluminescence (TL) saturation around ∼ (10–40) kGy. Still dose estimates for such high radiation dose (HRD) range are not achieved. Significant research exists about luminescence response for low dose ranges (<250 Gy) but limited studies are done for HRDs (>1 kGy). This work characterizes the luminescence response of quartz for HRDs (1–21 kGy) to improve existing understanding of luminescence mechanism. Results show that the characteristics of the trap (<200 °C) differ significantly at HRDs than low doses. TL in multi-spectral detection (UV–Visible) band suggest an increase in 340–380 °C peak intensity up to 11 kGy dose. The measurements of saturation dose suggest that it depends on the trapping centres but is independent of recombination centres for the samples used for study. The traps are found bleachable by sunlight, reducing TL signal to residual levels in 1 h. Further, the bleachability is found to be anti-correlated with luminescence emission wavelength. At HRDs luminescence sensitivity is influenced by dose given in previous cycle which is difficult to correct by routine normalization procedures. The work also explores the various normalization methods to find appropriate method for HRD estimation and recommends the use of mass normalization as other normalization methods do not correct the sensitivity changes at HRDs adequately.

Residual levels of pesticides in filet green beans from Souss-Massa, Morocco.

A total of 30 samples of filet green beans (Phaseolus vulgaris) from various popular markets in the Souss-Massa region (Morocco) were analyzed during 2021 for the presence of pesticide residues. We performed a QuEChERS extraction (Quick, Easy, Cheap, Effective, Rugged, and Safe) combined with Liquid Chromatography-Mass Spectrometry (LC-MS/MS) and Gas Chromatography-Mass Spectrometry (GC-MS/MS). The method was validated in accordance with SANTE 11312/2021 guidelines. The results of this survey indicated that 8 out of 30 green bean samples are positives (0.015 to 0.112mg/kg). Azoxystrobin was the most frequently detected pesticide, occurring in 5 samples. For authorized pesticides, none of the samples exceeded the European Maximum residue level (EU MRL) in green beans, but residue of fipronil-unauthorized substance was detected in one sample at 0.027mg/kg. Hence, it is important to increase inspections for locally marketed fresh green beans and align agricultural practices with regulatory requirements.

Influence of Organic Loading Rates on the Treatment Performance of Membrane Bioreactors Treating Saline Industrial Wastewater

This study investigated the efficacy of membrane bioreactor (MBR) technology in treating saline industrial wastewater, focusing on the impact of the organic loading rate (OLR) and the food-to-microorganism (F/M) ratio on treatment performance. This research utilized saline industrial wastewater from Al-Hasa, which had salinity levels ranging from 5000 to 6900 mg/L. It explored treatment processes at varying Chemical Oxygen Demand (COD) concentrations of 800, 1400, and 2000 mg/L, corresponding to an OLR of 0.80 ± 0.05, 1.41 ± 0.07, and 1.98 ± 0.12 g COD/L, respectively. The average F/M ratios used were 0.20, 0.36, and 0.50 g COD/g MLSS·d, maintaining a constant Sludge Residence Time (SRT) of 12 days, a hydraulic retention time (HRT) of 24 h (hrs.), and a flux of 10 L/m2·h. The MBR system demonstrated high COD removal efficiencies, averaging 95.7 ± 1.6%, 95.5 ± 0.4%, and 96.1 ± 0.3%, alongside Biochemical Oxygen Demand (BOD) removal rates of 98.3 ± 0.2%, 99.8 ± 0.1%, and 98.5 ± 0.1%, respectively. However, an increased OLR led to elevated residual COD and BOD levels in the treated effluent, with COD concentrations reaching 34.2 ± 12.8, 63.3 ± 5.9, and 76.5 ± 5.4 mg/L, respectively. This study also reveals a significant decline in ammonia and Total Kjeldahl Nitrogen (TKN) removal efficiencies as OLR increases, dropping from 96.1 ± 0.5% to 80.2 ± 0.9% for ammonia and from 83.8 ± 3.4% to 65.8 ± 2.3% for TKN. Furthermore, higher OLRs significantly contribute to membrane fouling and elevate the transmembrane pressure (TMP), indicating a direct correlation between OLRs and operational challenges in MBR systems. The findings suggest that for optimal performance within the Saudi disposal limits for industrial wastewater, the MBR system should operate at an F/M ratio of ≤0.33 g COD/g of Mixed Liquor Suspended Solid (MLSS)·d. This study underscores the critical role of the OLR and F/M ratio in treating saline industrial wastewater using MBR technology, providing valuable insights for enhancing treatment efficiency and compliance with environmental standards.

Effect of controlling residual moisture in atmospheric plasma spray-Y2O3 coatings on random defect generation by halogen-based plasma

The fluorine-based plasma resistance properties of atmospheric plasma spray (APS)-Y2O3 coatings were investigated based on residual moisture control levels. APS-Y2O3 coatings at different moisture levels are exposed to F-poor (Ar, NF3, and O2) and F-rich (NF3 and O2) plasma. Outgassing varies with the residual moisture control level. When the plasma supplies sufficient energy, internal moisture reacts with the coating surface to form Y-OH, accelerating the coating degradation. This confirms the decreasing random defect occurrence in the moisture-controlled coatings. The F radical preferentially binds to Y-OH bonds, which have a lower strength than Y-O bonds in F-poor plasma, and reacts with Y-OH and Y-O bonds to form YOxFy in F-rich plasma. YOxFy formed by Y-OH bonds is vulnerable to plasma owing to its low binding strength, which accelerates the formation of random defects. This study highlights the importance of reducing random defects by effective moisture control.