Variation In Surface Area Research Articles

Temporal variation in glacier surface area and glacial lakes in glaciated river basins of Arunachal Pradesh

Abstract Climate change-induced glacier recession has sparked a dynamic transformation of glaciers in high-mountain areas worldwide, resulting in genesis, expansion, and dissipation of glacial lakes that pose a potential threat to downstream communities, underscoring the need for regular monitoring. This study incorporates the automated glacier extraction index to improve debris-free glacier mapping accuracy by reducing water and shadow area categorization errors using multi-temporal Landsat-5 Thermal Mapper, Landsat-8 Operational Land Imager, and digital elevation model (Shuttle Radar Topography Mission) to obtain precise glacier extent. Waterbodies were delineated using thresholding techniques applied to water indices: normalized difference water index, modified normalized difference water index, normalized difference turbidity index, and slope information. The study attempted to map and analyze the temporal variations of glaciers and glacier lakes in the glaciated sub-basins of Arunachal Pradesh: Dibang Basin, Mago Basin, and Subansiri Basin. Glaciers receded at a shrinkage rate of 1.08% per year (1988–2017) in Mago Basin, 1.01% per year (2013–2022) in Subansiri Basin, and 1.42% per year (1995–2021) in Dibang Basin. Glacier lakes showed an increasing trend in number and area due to glacier melt, expanding at rates of 3.31% in the Mago Basin, 0.48% in the Subansiri Basin, and 0.68% in the Dibang Basin per year. Findings suggest that global climate change is likely the primary factor driving glacier changes in these basins.

Impact of Low Catalyst Loading and Incorporation of Additives on Structure and Performance of PEM Electrolyzer Catalyst Layers

Polymer electrolyte membrane water electrolyzers (PEMWEs) are an important technology that can produce renewable hydrogen on demand, although with challenges posed by the slow kinetics of the anodic oxygen evolution reaction (OER) and degradation issues. The degradation of membrane electrode assemblies (MEAs) prepared with Ir-based catalysts is not well understood, especially with lower-loading catalyst layers and intermittent load inputs. This work investigates low-loading IrO2 catalyst layers made with different carbon-based additives, including high-surface-area carbon (HSC), graphitized HSC (gHSC), Vulcan, graphitic carbon nanofibers (gCNFs), graphitic nanoplatelets (gNPs), nitrogen-doped carbon spheres (NCs), Ti carbide (TiC) and Ti carbonitride (TiCN). While carbon-based supports have issues with corrosion at high oxidizing potentials, these materials provide a range of variations in morphology, shape, size, surface area, graphitization, and composition, allowing exploration of the impact of these parameters on catalyst layer structure to identify promising routes to improve catalyst layer structures. Catalyst layers were characterized with electron microscopy and x-ray spectroscopy to assess the distribution of catalyst, carbon additive, and ionomer. This information was correlated with electrochemical performance measurements to elucidate the impact on kinetic site access and mass transport. Selected samples were also subjected to more extended operation to investigate how the initial structures and their performance evolved.

The distribution of depth, volume, and basin shape for lakes in the conterminous United States

AbstractDepth regulates many attributes of aquatic ecosystems, but relatively few lakes are measured, and existing datasets are biased toward large lakes. To address this, we used a large dataset of maximum (Zmax; n = 16,831) and mean (Zmean; n = 5,881) depth observations to create new depth models, focusing on lakes < 1,000 ha. We then used the models to characterize patterns in lake basin shape and volume. We included terrain metrics, water temperature and reflectance, polygon attributes, and other predictors in a random forest model. Our final models generally outperformed existing models (Zmax ; root mean square error [RMSE] = 8.0 m and Zmean ; RMSE = 3.0 m). Our models show that lake depth followed a Pareto distribution, with 2.8 orders of magnitude fewer lakes for an order of magnitude increase in depth. In addition, despite orders of magnitude variation in surface area, most size classes had a modal maximum depth of ~ 5 m. Concave (bowl‐shaped) lake basins represented 79% of all lakes, but lakes were more convex (funnel‐shaped) as surface area increased. Across the conterminous United States, 9.8% of all lake water was within the top meter of the water column, and 48% in the top 10 m. Excluding the Laurentian Great Lakes, we estimate the total volume in the conterminous United States is 1,057–1,294 km3, depending on whether Zmax or Zmean was modeled. Lake volume also exhibited substantial geographic variation, with high volumes in the upper Midwest, Northeast, and Florida and low volumes in the southwestern United States.

K2CO3‐loaded γ‐Al2O3 for acid removal in waste transformer oil

AbstractTransformer oil plays a critical role in ensuring the insulation and normal operation of power transformers. However, during operation, the transformer oil would undergo oxidation and degradation, leading to the formation of acids and polar compounds that increase its acidity and degrade its performance. Hence, the recycling and regeneration of aged transformer oil is an essential practice in transformer maintenance, contributing significantly to the extension of a transformer's operational lifespan and the reduction of potential risks. Adsorption separation is a preferred method for regeneration, offering simplicity and high efficiency. This study focuses on impregnated γ‐Al2O3 as an adsorbent for acidity removal in waste transformer oil. We conducted static adsorption experiments to investigate the optimal loading amount of the active component and the best calcination temperature for acid removal. XRD technique is employed to monitor the phase changes of the carrier during the calcination process. BET analysis is used to observe variations in the specific surface area and pore volume of the adsorbent during the modification process. DTG‐TGA is utilized to assess the weight loss during the calcination process. FTIR is employed to observe changes in functional groups during modification and adsorption processes. Along with these investigations, a study is also carried out to assess the dynamic acid removal performance of the acid‐removing adsorbent loaded into a fixed bed. The findings contribute to the development of sustainable methods for regenerating transformer oil, ensuring efficient and environmentally friendly operations.

General prediction models for void fraction and specific surface area of gas–liquid microflows

AbstractThe flow characteristics of void fraction and specific surface area are important to predict the mass transfer and reaction performances in gas–liquid microreactors. However, the models and trends for the two parameters in different flow patterns remain ununified and insufficient. Accordingly, this work first time studies the void fraction and specific surface area in a very wide flow pattern range (Taylor, short bubble, bubbly, and bubble swarm flow). The results show that at the same gas–liquid flow rates, the void fraction decreases with bubble size in Taylor and short bubble flow but is totally opposite in bubbly and bubble swarm flow. Importantly, the variation of specific surface area with bubble size is independent of the flow pattern and decreases with bubble size. Finally, based on bubble size, two general models for the two parameters are developed. This work provides a new direction for the unification of flow characteristics.

Varying Heat Release Rates per Unit Area – The Impact in Underground Mines

Abstract The fire behaviour and smoke behaviour of a fire in an underground mine will be largely dictated by the heat release rate of the fire. The heat release rate per unit area is generally the output from small-scale fire experiments and can be applied for larger objects with varying surface area. This paper studies the impact of varying heat release rate per unit area for fires in materials and substances typically found underground. Data from earlier fire experiments were analysed and discussed, and several different heat release rate curves and flame spread velocities for various fuel components were developed and discussed. It was found that the hydraulic hose presented the highest peak heat release rate per unit area of the solid fuel items, followed by the low-voltage cable, cab interior, and tyre in descending order. The increase in the peak heat release rate was highest for the highest incident heat flux levels, representative for scenarios underneath a mining vehicle. The heat release rate per unit area of pool fires underneath a vehicle is significantly higher than a corresponding free burning case - attributed to the higher incident heat flux – but a gravel surface underneath a pool fire will reduce the heat release rate considerably. Line fires in larger bundles of electrical cables were modelled and found to attain the peak flame spread velocity more rapidly compared with a fire in hydraulic hoses. This was caused by the higher heat release rate of the initial fire and ignited segments in the electrical cable case.

Sulfur-Doped porous carbon Adsorbent: A promising solution for effective and selective CO2 capture

The effective and selective capture of CO2 through the rational design of microstructures and the synthesis of carbon materials with enriched surface functionality is of utmost importance in mitigating CO2 emissions. In this study, we successfully prepared a novel type of S-doped porous carbon material with a high surface area and a significant volume of micropores in a straightforward manner. This was achieved by pyrolyzing carbonized coconut shells (CS) with potassium thiosulfate K2S2O3 (PT) as an activating and sulfur supply agent. By adjusting the pyrolysis temperature within the range of 650–750 °C, we obtained carbon materials with varying surface areas (887–1924 m2/g), pore volumes (0.35–0.95 cm3 g−1), and a homogeneous distribution of sulfur content (up to 12.26 wt%) within the carbon framework. The optimal S-doped porous carbon demonstrated the adsorption capacities of 3.59 mmol g−1 at 25 °C and 5.31 mmol g−1 at 0 °C under 1 bar. Additionally, the prepared sorbent exhibited favorable CO2/N2 selectivity, high isosteric heat, and stable cycling performance. These excellent CO2 capture properties can be attributed to the materials' high microporosity and well-dispersed sulfur functionality in the carbon framework. Collectively, these findings highlight the potential of these novel carbon materials with heteroatom doping as efficient adsorbents for the selective capture of CO2, presenting a viable solution in the quest for effective CO2 mitigation.

Cyprus Surface Water Area Variation Based on the 1984–2021 Time Series Built from Remote Sensing Products

Cyprus experiences the highest level of water stress among European Union countries due to several interplaying factors such as rainfall variability and increasing water demand. These instigate the nation to build dams on almost all rivers of the island to satisfy the requirements for drinking water and irrigation. Many studies have been primarily conducted on assessing water availability for various uses, particularly for drinking water supply and irrigation. However, there is still a gap/less explored area in terms of a better understanding of changes in surface water over time. Thus, this study aims to evaluate the water surface area variation in Cyprus over the past four decades based on remote sensing products, timeseries analysis and trend detection. The result reveals a statistically significant increasing trend (p < 0.05) in water surface area between 1984–2021. However, following the completion of the final reservoir in 2010, a statistically significant decreasing trend (p < 0.05) was observed in the permanent water surface area. This decline is related to both climatic variability and increased water demands. We observed cycles of 6, 8, and 11 years in permanent water. These cycles indicate a recurring pattern of water scarcity, with severe implication already observed on both economic activity and agriculture. The recent decade has witnessed a decline in rainfall, and this is evident through the decrease in vegetation greenness in rainfed agricultural regions, highlighting its impact. Therefore, the findings of this study underscore not only the necessity for the development of infrastructure aimed at conserving water, but also reinforces the need to discuss water use priorities in Cyprus.

Optimization of moving bed biofilm reactors for the treatment of municipal wastewater

The properties of biocarriers significantly influence the performance of a moving bed-biofilm reactor (MBBR). This study aimed to assess the impact of media type, filling ratio, and hydraulic retention time (HRT) on biofilm formation and MBBR performance in both batch and continuous setups using real municipal wastewater. Two different media, high-density polyethylene (HDPE) and polypropylene (PPE), with varying surface area and properties were used. Biofilm growth and MBBR performance were monitored and optimized using response surface methodology. The effect of different media was investigated for three filling ratios of 20%, 40% and 60% and HRT of 4, 6 and 8 h. Results depicted a better biofilm growth on HDPE media in comparison to PPE carriers due to difference in media structure and surface properties. At all the conditions tested, HDPE media showed comparatively better performance for the removal of organic matter and nutrients than PPE media. The maximum organic matter removal efficiency was found as 77% and 75% at an HRT of 6 h and filling ratio of 40% for HDPE and PPE media, respectively. The ammonia removal was also found better for HDPE media due to its geometry and structure favoring the anoxic conditions with maximum removal of 89% achieved at 6-h HRT and 40% filling ratio. Overall, the system with HDPE media indicated more stability in terms of reactor performance than PPE carriers with variations in the operating conditions.

A new approach towards extracorporeal gas exchange and first invitro results.

Extracorporeal life support (ECLS) pertains to therapeutic and prophylactic techniques utilized in a wide range of medical applications, with severe pulmonary diseases being the most prominent cases. Over the past decades, little progress has been made in advancing the basic principles and properties of gas exchangers. Here, in an unconventional approach, dialysis hollow fibers are handled with silicone to create a purely diffusive coating that prevents plasma leakage and promotes gas exchange. Commercial dialyzers of varying surface area and fiber diameter have been coated with silicone, to determine the impact of each parameter on performance. The impermeability of the silicone layer has been validated by pressurization and imaging methods. SEM images have revealed a homogeneous silicone film coating the lumen of the capillaries, while fluid dynamic investigations have confirmed its purely diffusive nature. The hemodynamic behavior and the gas exchange efficiency of the silicone-coated prototypes have been investigated invitro with porcine blood under various operating conditions. Their performance has been found to be similar to that of a commercial PMP oxygenator. This novel class of gas exchangers is characterized by high versatility and expeditious manufacturing. Intraoperability between conventional ECLS systems and dialysis machines broadens the range of application infinitely. Ultimately, long-term clinical applicability ought to be determined over invivo animal investigations.

Translated article] Chronic outpatient treatment with topical sevoflurane in patients with vascular ulcers

ObjectiveTo show the effectiveness and safety of topical sevoflurane after ambulatory and prolonged administration in patients with refractory vascular ulcers . MethodsRetrospective observational study analysing clinical improvement and vascular ulcers surface area variation after topical application of sevoflurane. Inclusion criteria were patients with painful vascular ulcers refractory to usual therapies and who were treated with topical sevoflurane for at least 36 months. The following variables were collected: age, sex, medical history, associated comorbidity, ulcer aetiology, and medical treatment. The visual analogue scale was used to measure baseline and break through pain intensity before and after treatment. ResultsNine patients met the inclusion criteria of the total number of patients treated whose median age was 74.8±7.5 years. Cases 2 and 9 died during follow-up. In all cases, the analgesic action of topical sevoflurane was rapid (3.1±2.1 min), intense (visual analogic scale: 7±1.1 to 1.4 ± 1.1 points), and long-lasting (6–24 h). With the exception of case 4, all patients experienced a large reduction in vascular ulcers surface area (15.1±5.0 to 2.7±4.2) and tolerance wasn't observed over time. ConclusionTopical application of sevoflurane is an analgesic and re-epithelialising strategy for vascular ulcers with a successful safety profile.

Identification of Differences in Body Composition Measures Using 3D-Derived Artificial Intelligence from Multiple CT Scans across the L3 Vertebra Compared to a Single Mid-Point L3 CT Scan.

Body composition analysis in colorectal cancer (CRC) typically utilises a single 2D-abdominal axial CT slice taken at the mid-L3 level. The use of artificial intelligence (AI) allows for analysis of the entire L3 vertebra (non-mid-L3 and mid-L3). The goal of this study was to determine if the use of an AI approach offered any additional information on capturing body composition measures. A total of 2203 axial CT slices of the entire L3 level (4-46 slices were available per patient) were retrospectively collected from 203 CRC patients treated at Western Health, Melbourne (97 males; 47.8%). A pretrained artificial intelligence (AI) model was used to segment muscle, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) on these slices. The difference in body composition measures between mid-L3 and non-mid-L3 scans was compared for each patient, and for males and females separately. Body composition measures derived from non-mid-L3 scans exhibited a median range of 0.85% to 6.28% (average percent difference) when compared to the use of a single mid-L3 scan. Significant variation in the VAT surface area (p = 0.02) was observed in females compared to males, whereas male patients exhibited a greater variation in SAT surface area (p < 0.001) and radiodensity (p = 0.007). Significant differences in various body composition measures were observed when comparing non-mid-L3 slices to only the mid-L3 slice. Researchers should be aware that considering only the use of a single midpoint L3 CT scan slice will impact the estimate of body composition measurements.

Isolating the drivers of the species‐area relationship in experimental habitat islands

AbstractAimConsidered one of ecology's laws, the species‐area relationship (SAR) is among the most intensively studied ecological phenomena, yet the mechanisms through which the SAR arises and under what circumstances remain poorly understood. Here, we experimentally test the effects of area alone in the absence of commonly invoked mechanistic drivers of the SAR in both sub‐tidal bay and inter‐tidal marsh habitats.LocationLouisiana, U.S.A.TaxonInvertebrate macrofauna.MethodsTo determine if surface area alone may generate the SAR, we conducted a small‐scale, ephemeral habitat island experiment in a subtidal soft‐bottom bay and in an intertidal soft‐bottom coastal salt marsh. Cellulose sponge habitat islands of varying surface areas, but with constant energy content and habitat diversity, were deployed in each location to isolate the effects of surface area on the SAR in the absence of species‐energy relationships and habitat diversity.ResultsArea alone, likely through passive sampling, generated significant SARs in both habitats, with the salt marsh producing the strongest relationship, likely due to differential physical structuring between habitats. Communities of low surface area sponges were generally nested within those of high surface area sponges, and dispersal limitation may have increased the importance of nestedness relative to species replacements in structuring communities between habitats.Main ConclusionsThat area alone, in the absence of covariates such as energy availability and habitat diversity may, significantly impact the species richness of experimental and ephemeral marine benthic habitat island communities. Our methodology may provide a new avenue for SAR research, allowing for the isolation and simultaneous testing of potential drivers through the physical manipulation of ephemeral habitats.

Direct In Situ Determination of the Surface Area and Structure of Deposited Metallic Lithium within Lithium Metal Batteries Using Ultra Small and Small Angle Neutron Scattering

AbstractDespite being the major cause of safety and performance issues in lithium metal batteries, experimental difficulties in quantifying directly the morphology of lithium deposited at electrode surfaces have meant that the mechanism of metallic lithium growth within batteries remains elusive. This study demonstrates that quantitative detail about the morphology of metallic lithium within batteries can be derived non‐destructively and directly using in situ ultra‐small and small‐angle neutron scattering. This information is obtained over a large electrode area in cells where lithium deposition processes are typical of real‐world applications. Complex variations of surface area and interfacial distances 1–10 µm and 100–300 nm are revealed in size that are influenced by current density and cell cycling history, providing valuable insight into the growth of metallic lithium features detrimental to battery performance. Such quantitative insight into the process of lithium growth is required for the development of safer high‐performance lithium metal batteries.

Estimation of Variation of Surface Area and Volume of Water in Fishing Bays of Lake Baikal

The research estimated the water surface area and volume of the bay Proval and Posol'skiy sor in Lake Baikal by using the QGIS geographic information system. The research indicated that the bays in question were very sensitive to changes in the water level of Lake Baikal. Surface area has been found to be more sensitive to changes in water level than volume. These indicators are important for the estimation of the receiving capacity of an area and can be used to predict the quantity of receiving capacity in low water periods. The results obtained may be useful in taking measures to stabilize the population of Baikal omul and its rational use.

Diversity and evolution of cerebellar folding in mammals.

The process of brain folding is thought to play an important role in the development and organisation of the cerebrum and the cerebellum. The study of cerebellar folding is challenging due to the small size and abundance of its folia. In consequence, little is known about its anatomical diversity and evolution. We constituted an open collection of histological data from 56 mammalian species and manually segmented the cerebrum and the cerebellum. We developed methods to measure the geometry of cerebellar folia and to estimate the thickness of the molecular layer. We used phylogenetic comparative methods to study the diversity and evolution of cerebellar folding and its relationship with the anatomy of the cerebrum. Our results show that the evolution of cerebellar and cerebral anatomy follows a stabilising selection process. We observed two groups of phenotypes changing concertedly through evolution: a group of 'diverse' phenotypes - varying over several orders of magnitude together with body size, and a group of 'stable' phenotypes varying over less than 1 order of magnitude across species. Our analyses confirmed the strong correlation between cerebral and cerebellar volumes across species, and showed in addition that large cerebella are disproportionately more folded than smaller ones. Compared with the extreme variations in cerebellar surface area, folial anatomy and molecular layer thickness varied only slightly, showing a much smaller increase in the larger cerebella. We discuss how these findings could provide new insights into the diversity and evolution of cerebellar folding, the mechanisms of cerebellar and cerebral folding, and their potential influence on the organisation of the brain across species.

Paleoglaciological reconstruction and geomorphological mapping of Dobrowolski Glacier, King George Island, Antarctica

The paper aims to reconstruct the fluctuations of Dobrowolski Glacier, a tidewater glacier located in the inner position of the Admiralty Bay (King George Island, Antarctica), from the Little Ice Age (1400-1700) until the present. Measurements of the glacier’s area and length were based on multitemporal satellite imagery and submarine glacial landforms. The glacier surface area variations between the Little Ice Age and 2014 A.D were estimated. Morainic banks and paleoglacial reconstructions provided evidence of fluctuations in the surface area of the glacier between PIG and 2014 AD. Therefore, four stages of analysis were established: Stage I (Part I) (1400 to 1700), Stage I (Part II) (1700 until the mid-20th century), Stage II (mid-20th century until the 1980s), Stage III (1980 to 2000), and Stage IV (2000 to 2020). The climate during the Little Ice Age triggered the last major glacial advance, and their grounding line position was recorded by an external and prominent morainic bank. After the major glacial advance position of the grounding line, the ice-margin has undergone higher retreat rates (stage I) as response to the warming trend and the loss of anchoring point. The stage II (Unit B) is recorded by distal and discontinuous morainal ridges and glacial lineations formed in the context of an active ice flow at a deeper point in the fjord. During stage III (Unit C) glacial lineations and steep slopes occur, while landforms are less preserved, revealing a fast shrinkage phase. Stage IV is characterized by discontinuous morainic ridges (Unit D), when the glacier presents the highest annual glacial area loss. Currently, the accelerated shrinkage may be linked to the loss of anchorage on seamounts (serving as pinning points) and increased warming. The U-shaped valley geometry has also influenced the glacier shrinkage processes and the redirection of glacial paleoflow during the last 300 years. The retreat rate to mid-20th century-2020 period is higher than Little Ice Age- mid-20th century period.

Performance evaluation of the novel 3D-printed aquatic plant-microbial fuel cell assembly with Eichhornia crassipes

Plant-Microbial Fuel Cells (PMFCs) are a sustainable derivative of fuel cells that capitalizes on plant rhizodeposition to generate bioelectricity. In this study, the performance of the novel 3D-printed aquatic PMFC assembly with Eichhornia crassipes as the model plant was investigated. The design made use of 1.75 mm Protopasta Conductive Polylactic Acid (PLA) for the electrodes and 1.75 mm CCTREE Polyethylene Terephthalate Glycol (PETG) filaments for the separator. Three systems were prepared with three replicates each: PMFCs with the original design dimensions (System A), PMFCs with cathode-limited surface area variations (System B), and PMFCs with anode-limited surface area variations (System C). The maximum power density obtained by design was 82.54 µW/m2, while the average for each system is 26.99 µW/m2, 36.24 µW/m2, and 6.81 µW/m2, respectively. The effect of variations on electrode surface area ratio was also examined, and the results suggest that the design benefits from increasing the cathode surface area up to a cathode-anode surface area ratio of 2:1. This suggests that the cathode is the crucial component for this design due to it facilitating the rate-limiting step. Plant health was also found to be a contributing factor to PMFC performance, thereby suggesting that PMFCs are an interplay of several factors not limited to electrode surface area alone. The performance of the novel PMFC did not achieve those obtained from existing studies. Nevertheless, the result of this study indicates that 3D-printing technology is a possible retrofit for PMFC technology and can be utilized for scale-up and power amplification.

Variation in bill surface area is associated with local climatic factors across populations of the plain laughingthrush.

Recent studies have found that avian bill and tarsus morphology may have evolved in response to climatic conditions, and these organs play important roles in thermoregulation and water retention in extreme environments. Here, we examined whether bill surface area and tarsus length were associated with climatic conditions in the plain laughingthrush, Garrulax davidi, which mainly occurs in north China and occupies several climatic zones from east to west. We measured bill surface area and tarsus length in 321 adults from 11 populations, almost encompassing all habitat types of the species. We analyzed the relationships among these morphological traits and local climatic factors. Bill surface area was positively correlated with maximum temperature, indicating that bill surface area tended to be larger in hotter environments. Furthermore, we found a negative relationship among bill surface area and winter precipitation, indicating that bill surface area tended to be larger in arid areas. However, we did not find any relationships between tarsus length and climatic factors. These results suggest that local climates may shape the evolution of bill morphology divergence, and summer seems to be the critical season for thermoregulation in this temperate zone passerine.

A Coin-Shaped Polypropylene Bio-Carrier Fabricated Using a Filament-Based 3D Printer for Wastewater Treatment

The utilization of the moving bed biofilm reactor (MBBR) has been identified as a promising technology for reducing water pollutants. This study focuses on designing a novel bio-carrier using 3D printing technology for use in an MBBR for wastewater treatment. The bio-carrier is made of polypropylene filament with four variations in specific surface area. The study investigates the relationship between the specific surface area and the amount of adhering biofilm on the bio-carrier. Results show that type-4 bio-carrier with a specific surface area of 1438.16 m2/m3 and a pore diameter of 1.8 mm to 4.9 mm has the highest mass of biofilm attachment at 2.598 grams. This research provides insights for designing bio-carriers with suitable pore diameters and specific surface areas for improved MBBR performance in wastewater treatment.