Search Results (194)

Membrane technology is primarily used for the separation and purification of biotechnological products, which contain proteins and enzymes. Membrane fouling during crossflow filtration remains a significant challenge. This study aims to initially validate crossflow filtration models, particularly related to pore-blocking mechanisms, through a comparative analysis with dead-end filtration models. One crossflow microfiltration (MF) and six consecutive ultrafiltration (UF) stages were implemented to concentrate laccase extracts from Pleurotus ostreatus 202 fungi. The complete pore-blocking mechanism significantly impacts the MF, UF 1000, UF 100 and UF 10 stages, with the highest related filtration constant (Kb_F) estimated at 12.60 × 10⁻⁴ (m⁻¹). Although the intermediate pore-blocking mechanism appears across all filtration stages, UF 100 is the most affected, with an associated filtration constant (Ki_F) of 16.70 (m⁻¹). This trend is supported by the highest purification factor (6.95) and the presence of 65, 62 and 56 kDa laccases in the retentate. Standard pore blocking occurs at the end of filtration, only in the MF and UF 1000 stages, with filtration constants (Ks_F) of 29.83 (s^−0.5m^−0.5) and 31.17 (s^−0.5m^−0.5), respectively. The absence of cake formation and the volume of permeate recovered indicate that neither membrane was exposed to exhaustive fouling that could not be reversed by backwashing. Full article

This study systematically explored the performance of a vacuum membrane distillation (VMD) system equipped with polytetrafluoroethylene (PTFE) hollow fiber membranes for treating simulated, acidic, low-level radioactive liquid waste. By focusing on key operational parameters, including feed temperature, vacuum pressure, and flow velocity, an orthogonal experiment was designed to obtain the optimal parameters. Considering the potential application scenarios, the following two factors were also studied: the initial nuclide concentrations (0.5, 5, and 50 mg·L⁻¹) and tributyl phosphate (TBP) concentrations (0, 20, and 100 mg·L⁻¹) in the feed solution. The results indicated that the optimal operational parameters for VMD were as follows: a feed temperature of 70 °C, a vacuum pressure of 90 kPa, and a flow rate of 500 L·h⁻¹. Under these parameters, the VMD system demonstrated a maximum permeate flux of 0.9 L·m⁻²·h⁻¹, achieving a nuclide rejection rate exceeding 99.9%, as well as a nitric acid rejection rate of 99.4%. A significant negative correlation was observed between permeate flux and nuclide concentrations at levels above 50 mg·L⁻¹. The presence of TBP in the feed solution produced membrane fouling, leading to flux decline and a reduced separation efficiency, with severity increasing with TBP concentration. The VMD process simultaneously achieved nuclide rejection and nitric acid concentration in acidic radioactive wastewater, demonstrating strong potential for nuclear wastewater treatment. Full article

Objectives: Odontogenic sinusitis (ODS) is common but frequently overlooked condition that differs from rhinogenic sinusitis (CRS) and should be suspected in each case of unilateral sinusitis. Clinical symptoms such as foul smell, congestion, rhinorrhea, and unilateral maxillary sinus opacification with overt dental pathology on radiological scans are more suggestive of ODS than CRS, but the distinctive microbiological flora are another clinical factor in diagnosis. The aim of this study was to compare the microbiological load of ODS and CRS and their clinical presentation for better disease recognition and its predisposing factors. Methods: Adult patients scheduled for endoscopic sinus surgery were included in the study. Clinical data and radiological images were analyzed. The otolaryngologist assessed nasal endoscopy for mucopurulence or edema in middle meatus or sinuses, whereas dental specialist confirmed or ruled out the dental cause. Microbiological samples were collected after endoscopic maxillary antrostomy. After irrigation with 0,9% saline, the aspirated rinse was collected into sterile sets and sent for culturing. Results: The study group consisted of 84 patients, 55 with CRS and 29 with ODS. Streptococcus spp prevailed in the CRS group, whereas Staphylococcus spp prevailed in the ODS group. Statistically significant differences between the groups were found in type of discharge, degree of edema, and presence of polyps. However, no statistical correlations were noted for presence of bacteria in the culture and endoscopic or radiological findings. Conclusions: ODS and CRS share some common features: ODS more often presents with purulent discharge, localized maxillary involvement, and the presence of oral pathogens, and Staphylococcus spp in microbial profile. Full article

Recovering oil and water from palm oil mill effluent reduces environmental pollution and promotes sustainable practices. An effective method to achieve this is ultrafiltration (UF), which uses semi-permeable membranes to separate oil, solids, and other contaminants from wastewater under pressure. To assess the most effective recovery method, an experimental comparison was conducted between PVDF and α-Al₂O₃ UF membranes at constant permeate of 20–50 LMH for PVDF and 20–70 LMH for α-Al₂O₃ membranes. Both membranes achieved 99.8% chemical oxygen demand (COD) rejection, with oil concentration factor (F_o) of 186.8% and 253.0%, and water recovery (R_w) of 46.6% and 60.5%, respectively. The permeate water quality was superior to the Malaysian discharge standards, and the fat, oil, and grease (FOG) content was suitable for phase separation processes. The optimal permeate fluxes, with stable transmembrane pressures (TMP), were observed at 40 LMH (PVDF) and 60 LMH (α-Al₂O₃). Total resistance (R_t) values were 1.30 × 10¹² m⁻¹ (PVDF) and 1.59 × 10¹² m⁻¹ (α-Al₂O₃). The ratio of irreversible to total resistances (R_ir/R_t) was 0.02 (PVDF) and 0.06 (α-Al₂O₃), indicating minimal irreversible fouling. Overall, the α-Al₂O₃ membrane demonstrated superior performance in oil and water recovery with more stable operation compared to the PVDF membrane. UF membrane technology emerges as an efficient technique for recovering oil and water compared to conventional methods. Full article

Membrane filtration, including reverse osmosis filtration, is widely applied in water treatment worldwide, offering solutions to a broad range of separation challenges. However, due to the porous structure of membranes, they are prone to fouling, which reduces their efficiency and can eventually render the membranes incapable of functioning. In such cases, a systemic intervention becomes necessary, highlighting the importance of accurately predicting the expected fouling time. Various approaches for estimating fouling processes and times are well documented in the literature. However, a common limitation of these methods is that they typically assume constant and well-defined operating parameters over time. Under such stable conditions, the process can be described deterministically, and the fouling time can be predicted using straightforward extrapolation techniques. However, in industrial practice, process conditions often fluctuate due to multiple influencing factors, making fouling time a variable quantity. Therefore, it can be more appropriately treated as a random variable characterized by a mean value and standard deviation. Rather than predicting a precise fouling time, it is more relevant to define a probabilistic interval within which the fouling is expected to occur with a specified confidence level (e.g., 95%). The associated maintenance scheduling can then be optimized based on economic criteria. The probability-based model presented herein defines this interval based on operational measurements, thereby providing users with a time window during which maintenance should be planned. From this point forward, the exact timing of interventions becomes a matter of technical feasibility and economic optimization. Full article

Laser surface texturing (LST) is a versatile method for enhancing material surface properties, offering high precision and flexibility for surface modification. This review comprehensively examines the application of laser texturing technology for surface protection and functional regulation of aluminum alloys, focusing on wettability, anti-icing, corrosion resistance, and wear resistance. It highlights recent progress in laser surface patterning techniques, describing the principles and attributes of methods such as direct laser writing, laser interference patterning, and laser shock treatment. The influence of laser intensity, scanning velocity, and texture spacing on surface topography is discussed thoroughly. Mechanisms of wettability control via laser surface texturing are summarized, emphasizing the key factors required to achieve superhydrophobic or hydrophilic properties through texture design. Advancements in enhancing anti-icing, anti-frost, anti-fouling, and anti-corrosion properties through multi-scale textures and their synergistic effects with functional coatings are analyzed. Additionally, the enhancement of wear resistance and friction performance under both dry and lubricated conditions is reviewed, with a focus on how the geometry and arrangement of textures affect the coefficient of friction and wear rate. Finally, the paper addresses challenges and future directions, including process optimization, scalability, and the integration of LST with advanced coatings to maximize its potential in aluminum alloy applications. Full article

The Mediterranean Sea is considered a hotspot for bioinvaders. Nonetheless, information on non-indigenous benthic foraminifera is still fragmented. This study documents for the first time the presence along the northwestern Adriatic coast of the non-indigenous benthic foraminifera species Virgulinella fragilis, Grindell and Collen (1976). Due to the low abundance recorded in the study area, the presence of this species may represent an early colonization phase. We discuss the temporal and spatial patterns of V. fragilis arrival in the Mediterranean and Adriatic Seas, and we hypothesize stowaway transport (via ship fouling or ballast water) as the main introduction pathway. Morphological test analyses suggest that V. fragilis prefers a low oxygen content, consistent with the ecological requirements reported for this taxon in the literature. The application of Maximum Entropy (MaxEnt) modeling indicates that the key factor influencing the presence of V. fragilis in the Mediterranean basin is the bacterial concentration expressed as NO₃. Projections under future climate scenarios (RCP 4.5) point to a decline of habitat suitability conditions, making widespread invasion unlikely in the Mediterranean. We emphasize the importance of continuous biomonitoring for early detection of alien species, improving our understanding of invasion dynamics and enabling prompt conservation actions, especially in regions impacted by anthropogenic activities. Full article

Spanning two decades (2000–2021), this study delves into how TF-induced momentum shifts differ between regular season and playoff matchups, factoring in home-court advantage and team score status at the time of the call. Analyzing 4196 cases of technical fouls (TFs) called against coaches, we employ big data analytics to uncover distinct patterns in momentum shifts and their strategic implications. Using advanced statistical modeling, we identify how these effects vary across game contexts, demonstrating how big data enhances decision-making in competitive sports. Logistic regression revealed a significant season-by-location interaction (p < 0.03). The findings revealed that, in the regular season, TFs in home games were associated with a 44%-win rate, compared to 28% in away games. However, in the playoffs, this shifted to 50% at home and 23% away. These results provide valuable insights into the TF–momentum shift phenomenon. Leveraging game analytics to identify patterns in TF-related momentum shifts can help coaches make more informed decisions, including pinpointing the optimal moments for TFs and other strategic actions. Full article

Antifouling paints are essentially used to prevent biological fouling of marine vessels and structures, but their release into the environment has resulted in various marine ecosystem problems. Irgarol, a representative antifouling paint substance, is well known for its direct effects on plankton productivity, but studies on its harmful effects on estuarine organisms are limited. This study aimed to determine the impact of irgarol exposure at the transcriptional level in Macrophthalmus japonicus, a highly dominant crab species in estuaries. To this end, we characterized the M. japonicus arginine kinase (AK) gene, which plays a role in energy metabolism in invertebrates, and examined its expression levels in response to irgarol exposure. Consequently, AK was identified as a highly prevalent enzyme in invertebrate species, including crustaceans and insects. Following irgarol exposure, the gills of M. japonicus exhibited relatively elevated AK gene expression compared to the control group at 4 and 7 days of exposure. In addition, elevated AK gene expression was observed in the hepatopancreas. Notably, the relatively low irgarol exposure concentrations of 1 and 10 μg L⁻¹ demonstrated comparatively higher AK gene expression in the hepatopancreas than the relatively high irgarol concentration of 30 μg L⁻¹. The results of this study imply that irgarol exposure may disrupt the equilibrium of energy metabolic processes regulated by AK gene expression in the M. japonicus crab. Moreover, the sustained environmental accumulation of irgarol indicates that it may serve as a significant disturbance factor within estuarine ecosystems. Full article

Per- and polyfluoroalkyl substances (PFASs) have been widely used in the production of consumer products globally due to the excellent water and oil resistance and anti-fouling properties. The multiple toxic effects of some PFASs also pose a threat to human health and ecosystem, and the frequent use of certain consumer products increased the risk of human exposure to PFASs. More data on the occurrence, concentration, and migration of PFASs in consumer products is urgently needed to address the possible risks posed by exposure to consumer products. This paper reviews the PFAS concentrations found, the migration characteristics known, and the exposure risks of PFASs arising from several types of consumer products over the last five years. The types of consumer products considered here include food contact materials, textiles, and disposable personal hygiene products. The influence of different factors on the migration process of PFASs from these products are summarized and discussed. Additionally, the main approaches and models of exposure assessment are evaluated and summarized. Current challenges and future research prospects in this field are discussed with a view to providing guidance for the future assessment and regulation of PFASs in consumer products. Full article

This study analyzes the design, installation, and performance evaluation of a photovoltaic farm located in Tulcea County, Romania, connected to a 20 kV distribution network. With a peak capacity of approximately 2800 kWp, the farm takes advantage of Romania’s favorable climate conditions and the support provided by renewable energy policies. The analysis covers both the photovoltaic panel array and the electrical energy evacuation system. The substation at the park is equipped with technology that complies with European standards and integrates advanced features typical of modern distribution networks. The operational performance evaluation includes detailed calculations of the performance ratio and power losses, attributed to factors such as temperature fluctuations, panel fouling, inverter efficiency, grid-related issues, and system availability. The farm contributes around 3620 MWh of electricity to the grid annually, demonstrating the important role of photovoltaic installations in promoting sustainable energy solutions at the regional level. Full article

From January to December 2022, a study on biofouling was conducted in the southeast wharf of Leizhou Bay. Over a year, a total of 44 species were recorded, belonging to 10 phyla. The dominant species in the community were coastal warm-water organisms typical of subtropical inner bay environments. The peak settlement period occurred between April and September, with the highest adhesion strength observed in summer. Among the dominant and representative species, Perna viridis stood out, followed by Podocerus brasiliensis, Crassostrea ariakensis, Musculus senhousei, Dreissena polymorphia, Caprella equilibra, Gammaropsis digitata, Stenothoe gallensis, Parhyale hawaiensis, Amphibalanus reticulatus, EnteromorpHa prolifera, Gracilaria bailinae, and Pennaria disticha. Due to competition for settlement space and food, individuals in the biofouling community exhibited mutual dependence or restraint and displayed a specific spatiotemporal distribution pattern adapted to environmental factors. Temperature was the most crucial environmental factor determining the geographic distribution of biofouling species, reflecting the differences in community composition across various climate zones. The number of species, settlement stage, and settlement rate of biofouling organisms were closely tied to water temperature. Additionally, local natural conditions such as salinity, dissolved oxygen, and light, as well as human activities such as aquaculture production, played significant roles in the settlement of biofouling organisms. Full article

In enclosed water bodies, water quality deterioration has emerged as a critical environmental issue. Eutrophication contributes to phenomena such as red tides and blue tides, raising concerns about foul odors and adverse impacts on surrounding aquatic ecosystems. Despite efforts to reduce nutrient loading through water quality management measures, reports of stagnant or a worsening water quality persist. One key factor is the accumulation of nutrients in deep layers. Nutrient-rich fluids form density currents along the lakebed, transporting nutrients and organic matter to deeper regions. This study investigates the hydrodynamic properties of a nutrient release from the lakebed in Lake Biwa using hydrodynamic and ecosystem models. The results reveal that a nutrient release triggers plume formation along sloping lakebed surfaces, facilitating the transport of nutrients and dissolved organic matter. Additionally, water circulation driven by density currents and nutrient concentrations along the slopes generate compensatory flows, leading to dynamic variability in Lake Biwa’s hydrodynamics. Full article

With the widespread use of plastic products, microplastic (MP) pollution has become an important factor threatening the water environment and human health. Ultrafiltration (UF) technology, based on organic polymer membranes, is a common method to remove MPs in water treatment processes, offering high removal efficiency and scalability. However, in water treatment plants (WTPs), oxidation pretreatment is often applied before UF, and the presence of oxidants can affect membrane performance. In this study, we constructed a polyvinylidene fluoride (PVDF) ultrafiltration membrane for a gravity filtration system to investigate the impact of sodium hypochlorite oxidation pretreatment on the removal of polystyrene (PS) MPs under gravity filtration. As a result, pre-chlorination reduced PS microplastic deposition on membranes by improving flux stability (15.1%) but significantly decreased the removal rate (from 36.6% to 22.6%). Pre-oxidation facilitated a shift in fouling behavior toward intermediate blocking while reducing standard blocking and enhancing irreversible fouling recovery. However, continuous chlorine exposure increased membrane porosity and pore size, substituted fluorine with chlorine, and led to organic carbon leaching, indicating pre-oxidation jeopardizes membrane stability and separation performance. These findings provide insights into the development of novel strategies aimed at enhancing the efficiency and sustainability of membrane treatment processes in WTPs. Full article

To overcome the limitations of traditional Reverse Osmosis (RO) desalination, Membrane Distillation (MD) has gained attention as an effective solution for improving the treatment of seawater and RO brine. Despite its potential, the formation of inorganic scales, particularly calcium sulfate (CaSO₄), continues to pose a major challenge. This research aims to explore the scaling mechanisms in MD systems through a combination of experimental analysis and dynamic modeling. Using real seawater and RO brine as feed sources, the scaling behavior was examined under various operational conditions, such as temperature and feed concentration. Optical Coherence Tomography (OCT) was utilized to monitor the real-time development of fouling layers, offering valuable insights into surface crystal formation processes. A System Dynamics Model (SDM) was created based on the experimental data to predict flux decline trends with precision. The model correlated well with experimental observations, highlighting key factors that drive scaling severity. This integrated approach deepens our understanding of scaling dynamics and provides actionable strategies to mitigate fouling in MD systems, thereby enhancing the efficiency and stability of MD desalination operations. Ultimately, this study underscores the potential of combining OCT with system dynamics modeling as a powerful approach for visualizing and validating scaling processes, offering a practical framework for optimizing MD performance and contributing to more sustainable desalination practices. Full article