Dry Conditions Research Articles

FS-DDPG: Optimal Control of a Fan Coil Unit System Based on Safe Reinforcement Learning

To optimize the control of fan coil unit (FCU) systems under model-free conditions, researchers have integrated reinforcement learning (RL) into the control processes of system pumps and fans. However, traditional RL methods can lead to significant fluctuations in the flow of pumps and fans, posing a safety risk. To address this issue, we propose a novel FCU control method, Fluctuation Suppression–Deep Deterministic Policy Gradient (FS-DDPG). The key innovation lies in applying a constrained Markov decision process to model the FCU control problem, where a penalty term for process constraints is incorporated into the reward function, and constraint tightening is introduced to limit the action space. In addition, to validate the performance of the proposed method, we established a variable operating conditions FCU simulation platform based on the parameters of the actual FCU system and ten years of historical weather data. The platform’s correctness and effectiveness were verified from three aspects: heat transfer, the air side and the water side, under different dry and wet operating conditions. The experimental results show that compared with DDPG, FS-DDPG avoids 98.20% of the pump flow and 95.82% of the fan flow fluctuations, ensuring the safety of the equipment. Compared with DDPG and RBC, FS-DDPG achieves 11.9% and 51.76% energy saving rates, respectively, and also shows better performance in terms of operational performance and satisfaction. In the future, we will further improve the scalability and apply the method to more complex FCU systems in variable environments.

Assessing Durability and Stability of Calcium Sulfoaluminate Cement-Stabilized Soils Under Cyclic Wet–Dry Conditions

Periodic wet–dry processes are a significant weathering mechanism that can quickly alter a soil’s mechanical characteristics, reducing its resilience and durability. This study investigates the physical and microstructural characterization of stabilized soils through experimental analysis. While the conventional approach to ground improvement involves the application of ordinary Portland cement (OPC) and lime for treating unstable soil, this research explores calcium sulfoaluminate (CSA) cement as an eco-friendly alternative with comparable efficacy and fewer adverse environmental effects. The primary objective is to evaluate the impact of cyclic wet–dry (W–D) events on the durability and stability of CSA cement-treated sand using comprehensive laboratory testing. Various samples were prepared with cement contents of 3%, 5%, 7%, and 10%, corresponding to the optimum moisture content. Stabilized soil specimens underwent testing for unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) after curing for 3, 7, 14, and 28 days. Subsequently, these specimens were exposed to zero, one, three, five, and seven W–D cycles. The outcomes show a decrease in the strength and durability index of the soil with a rising number of W–D cycles. However, the decline in the strength and durability of CSA-treated soil samples is significantly mitigated as the CSA content increases from 3% to 10%. The findings indicate that after seven W–D cycles, the UCS value of 10% cemented samples dropped by 14% after 28 days of curing, whereas 3% specimens experienced a 28% loss in strength. Similarly, UCS values for 5% and 7% cement content reduced from 666 kPa to 509 kPa and from 1587 kPa to 1331 kPa, respectively, indicating improved resilience with higher CSA content. The durability index was less affected during the first three cycles, but showed a more pronounced decline after five and seven cycles. For 3% cemented soil, the durability index dropped from 0.95 to 0.71, whereas for 10% cemented soil, it decreased from 0.97 to 0.82 after seven W–D cycles. The scanning electron microscope (SEM) also determines the cement–soil interaction before and after W–D, and it was noted that the pores and cracks increased after each cycle. Based on the findings, it is established that subgrade materials treated with CSA cement demonstrate durability, environmental sustainability, and suitability for integration into road construction projects.

3D MODELING COMPUTATION TO EVALUATE GROYNE STRUCTURE PERFORMANCE: CASE STUDY OF PASSO COASTAL AREA

Groyne is very important to protect the coastline with the concept of maintaining the balance of sediment transport. Groyne building in theory can work well if worked in groups or more than one. In this study, the Passo beach location was chosen because there is an existing groyne building that, if seen on Google Earth, has been damaged by the scattering of the constituent rocks. If the groyne cannot work to balance the sediment transport, it may occur that mass destruction to the infrastructure behind the groyne itself, such as regional roads, may occur. To find out the level of damage, an in-depth study needs to be carried out. In this paper, Delft-3D mathematical modeling was carried out to investigate groyne damage by looking at the performance of groyne in maintaining the balance of sediment transport in the Passo beach area. Hydrodynamic and coastal sediment modeling analyses were carried out in wet and dry season conditions. Modeling was carried out over one month with a morphology factor of 12 to obtain sediment transport for one year. In the existing dry season conditions, it shows that at the observation point, there is erosion of 2 meters, and in the wet season sediment transport is balanced. It is implied that the groyne structure must be replaced for being surpass the structure lifetime.

Chronic enrichment affects nitrogen removal in tidal freshwater river and estuarine creek sediments.

Population growth in coastal areas increases nitrogen inputs to receiving waterways and degrades water quality. Wetland habitats, including floodplain forests and marshes, can be effective nitrogen sinks; however, little is known about the effects of chronic point source nutrient enrichment on sediment nitrogen removal in tidally influenced coastal systems. This study characterizes enrichment patterns in two tidal systems affected by wastewater treatment facility (WWTF) effluent and assesses the impact on habitat nitrogen removal via denitrification. We collected intact sediment cores from prevalent habitats in a tidal freshwater river (TFZ; swamp forest) and a tidal estuarine creek system (EST; salt marsh) upstream and downstream of a WWTF outfall, and quantified dissolved gas fluxes across the sediment-water interface during wet conditions in early summer and dry conditions in late summer. Data collected during two synoptic water quality monitoring campaigns complimented laboratory experiments to provide environmental context for biogeochemical processing. The two systems exhibited different enrichment patterns such that the river-dominated TFZ system was characterized by consistently elevated nitrate + nitrite concentrations downstream of the WWTF, whereas precipitation and tidal influence affected nutrient distributions in the EST creek. Downstream sediments in TFZ exhibit an apparent saturation response, while upstream rates may be limited by other factors, such as labile organic matter availability. In contrast, downstream sediments in EST denitrify at higher rates than upstream during wet conditions that may enhance transport of effluent. This work provides information on ecosystem functioning in human-influenced environments and can be of use in developing nature-based solutions, such as water treatment wetlands, for nitrogen removal.

Investigations of Microstructures and Properties of SPEEK‐[BMIm][OTf] Ionic Liquid Composite Membrane for Fuel Cells

AbstractUtilizing ionic liquids in proton exchange membranes can greatly enhance the performance of fuel cells, enabling their application in high‐temperature and dry conditions. Further advancements in this field depend on a fundamental comprehension of their structural characteristics. This study focuses on the sulfonated poly(ether ether ketone) (SPEEK)‐1‐butyl‐3‐methylimidazolium trifluoromethanesulfonate [BMIm][OTf] composite membrane system. Effects of sulfonation degree, ionic liquid content, and temperature on the structure and conductivity of the composite membrane are investigated by dissipative particle dynamics (DPD) and molecular dynamics (MD) simulations. Results show that [BMIm][OTf] is predominantly distributed around the sulfonic acid groups of SPEEK. At an optimal sulfonation degree and ionic liquid content, interconnected ionic liquid channels can be formed. Nevertheless, an excessively high sulfonation degree may jeopardize the stability of the membrane structure. Moreover, the aggregation of ionic liquid occurs at a high level of ionic liquid content, which hinders the efficient transfer of protons. Generally, increasing the temperature is more conducive to the formation of monodisperse ionic liquid channels within the SPEEK‐[BMIm][OTf] composite membrane; however, overhigh temperature may compromise the integrity of the composite membrane structure. The findings of this study offer molecular insights for the development of high‐temperature proton exchange membrane fuel cell systems.

The Climatic Resilience of the Sasanian Empire

Abstract The Sasanian Empire (224–651 CE) has been given relatively little attention in research on climate-society interactions when compared to the neighboring Byzantine Empire, despite evidence of changing conditions and an agricultural economy that is theoretically vulnerable to droughts due to low annual precipitation. We review the available historical, archaeological, paleo-environmental, and paleo-climatic evidence to assess whether climatic conditions factored into periods of Sasanian growth and decline. We find evidence for drier conditions across Sasanian territories at the turn of the sixth century, a pattern that extends to the Aegean, Anatolia, and Central Asia. These same conditions contributed to a significant decline for the nearby Kingdom of Himyar but occurred alongside a period of expansion and intensification for the Sasanian Empire. We suggest that a combination of careful management of water infrastructure, including qanats, which can conserve water resources during dry periods, and land-use strategies that are both diverse and flexible, may have mitigated the worst impacts of this dry period. However, we note several weaknesses in the available data that still hinder confident interpretations of the potential impacts of climate change in the Sasanian Empire. Notably, there are gaps in the coverage of paleo-hydrological records and a complete lack of terrestrial paleo-temperature records in the region, as well as low resolution and high chronological uncertainties in the archaeological and paleo-environmental evidence.

Heatwave Future Changes From an Ensemble of Km‐Scale Regional Climate Simulations Within CORDEX‐FPS Convection

AbstractAs global temperatures continue to rise, the impact of heatwaves becomes increasingly striking. The increasing frequency and intensity of these events underscore the critical need to understand regional‐scale mechanisms and feedback, exacerbating or mitigating heatwave magnitude. Here, we use an ensemble of convection‐permitting regional climate models (CPRCMs) to elucidate future heatwave changes at fine spatial scales. We explore whether the recently highlighted drier/warmer signal introduced by CPRCMs improves summer temperature extremes representation and if it modulates future heatwave changes compared to convection‐parameterizing regional climate models (RCMs). In historical runs, CPRCMs show a more realistic representation of summer maximum temperature especially on a ground‐station‐based evaluation. CPRCMs project substantially drier conditions than RCMs. This is associated with a modulation of heatwave temperature changes which show diversified spatial patterns, magnitudes, and signs. CPRCMs ensemble shows an overall reduction in heatwave metrics future changes inter‐model spread compared to the RCMs ensemble.

Changes in the Antibacterial Performance of Polymer-Based Nanocomposites Induced by Additive Manufacturing Processing

The idea supporting the investigation of the current manuscript was to develop customized filters for air conditioners with different pore percentages and geometry with the additional advantage of presenting antibacterial performance. This property was expected due to the reinforcement of Cu nanoparticles in the polymeric matrix of poly(lactic acid) (PLA) and polyurethane (TPU). The filaments were characterized by their chemical composition, thermal and mechanical properties, and antibacterial behavior before and after processing by fused filament fabrication. An X-ray photoelectron spectroscopy showed that the nanocomposite filaments presented Cu particles at their surface in different valence states, including Cu0, Cu+, and Cu2+. After processing, the metallic particles are almost absent from the surface, a result confirmed by micro-computer tomography (μ-CT) characterization. Antibacterial tests were made using solid-state diffusion tests to mimic the dry environment in air conditioner filters. The tests with the nanocomposite filaments showed that bacteria proliferation was hindered. However, no antibacterial performance could be observed after processing due to the absence of the metallic element on the surface. Nevertheless, antimicrobial performance was observed when evaluated in liquid tests. Therefore, the obtained results provide valuable indications for developing new nanocomposites that must maintain their antimicrobial activity after being processed and tested in the dry conditions of solid-state diffusion.

Preparation of nitrogen-doped biocarbon from sewage sludge and pine sawdust for superior hydrogen sulfide removal: Experimental and DFT studies.

Hydrogen sulfide (H2S) is a major air pollutant posing a serious threat to both the environment and public health. In this study, a novel nitrogen-rich biocarbon that effectively removes H2S was produced from a mixture of sewage sludge and pine sawdust using melamine as nitrogen source. Compared with pristine biocarbons, nitrogen (N)-doped biocarbons possessed an adjustable porosity, e.g., higher specific surface area of 786-1547 m2/g, richer nitrogen content of 9.02-10.22%, and larger pore volume of 0.31-0.88 cm3/g. In particular, when H2S flow rate was 100 mL/min at 25 °C under dry conditions, a higher H2S adsorption capacity (376.7 mg/g) was observed on nitrogen-rich biocarbon pyrolyzed at 800 °C (BC800N) due to the larger surface area (1547 m2/g), higher pore volume (0.88 cm3/g), and richer nitrogen content (10.22%). The presence of CO2 in the gas reduced H2S adsorption; however, this was partially overcome by the presence of water vapor. After ten consecutive adsorption/desorption cycles, BC800N retained 96.7% of its adsorption capacity. Scanning electron microscopy, X-ray diffraction analysis, and quasi-in-situ X-ray photoelectron spectroscopy were employed to identify the transformed composites of H2S on the biocarbons. The higher nitrogen content resulting from melamine doping mainly increased the pyridinium N-6 and pyrrole N-5 levels, which serve as nitrogen-containing active sites for H2S adsorption. Density functional theory analysis confirmed that the N-6 atoms affected the adsorption of H2S molecules significantly and play an important role in gas adsorption. This innovative biocarbon material has the potential to facilitate optimized adsorption of H2S and assist in effectively mitigating the environmental impact thereof.

Tribological behavior under adhesion and dry friction conditions of copper-steel composites manufactured by wire-feed electron beam additive technology

Tribological behavior under adhesion and dry friction conditions of copper-steel composites manufactured by wire-feed electron beam additive technology

Technological evaluation of stones from the eastern region of the state of São Paulo, Brazil, for railway ballast

The correct choice of a stone aggregate for railway ballast is directly related to the stability, safety, efficiency, and maintenance costs of the track. The aggregate must meet several criteria to ensure it is the most appropriate material. Thus, the present study aimed to evaluate four distinct stones: two granites, a diabase, and a basalt, all mined in the eastern region of the state of São Paulo, Brazil, regarding their applicability as ballast. Using Brazilian and ASTM procedures for stone samples, the tests were conducted on 55 and 75-mm specimens, in dry and wet conditions. As a result, all stones met the physical properties established by the standards. Among the mechanical properties, uniaxial compressive strength stood out, with all stones where the tested materials advantageously exceeding the 100 MPa required by the Brazilian standard. Regarding the accelerated weathering test with ethylene glycol, only basalt showed more significant changes, although its resistance to weathering was still lower than 10%. Our findings indicate that these stones perform adequately as ballast for railway applications. The study is expected to contribute to revisions of technical standards and the improvement of a database on Brazilian stone materials for use as railway ballast.

A long-term drought reconstruction based on oxygen isotope tree ring data for central and eastern parts of Europe (Romania)

Abstract. This study investigates the relationship between oxygen isotope ratios (δ18O) in oak tree ring cellulose and past drought variability in Letea Forest, Romania. A δ18O site chronology spanning 1803–2020 was compiled from seven individual time series. δ18O values exhibited a significant negative correlation with moisture-related variables (cloud cover, relative humidity, and precipitation) and a positive correlation with temperature and sunshine duration. This confirms that δ18O from tree rings can be a good proxy for moisture availability. The strongest correlation was found between δ18O and the August Standardized Precipitation Evapotranspiration Index for an accumulation period of 9 months (SPEI9) for central and eastern Europe. This highlights SPEI9 as a superior indicator of drought compared to individual parameters like temperature or precipitation. Using a linear regression model, we reconstructed August SPEI9 variability for the past 200 years. The reconstruction captured interannual and decadal variations, with distinct wet and dry periods. Analysis of large-scale atmospheric circulation patterns revealed a link between high δ18O values (indicating dry conditions) and a high-pressure system over the North Atlantic. Conversely, low δ18O values (indicating wet conditions) corresponded to negative pressure anomalies over Europe. Moreover, extreme values of δ18O are also associated with the prevalence of a hemispheric teleconnection pattern, namely wave number 4. This δ18O chronology and the corresponding August SPEI9 reconstruction offer valuable tools for understanding past climate variability and its relationship with large-scale atmospheric and oceanic circulation patterns.

Using Microalgae as a Good Motivator of Ossimi Lamb's Health and Growth

ABSTRACTIn tropical and subtropical countries like Egypt, sheep breeding faces environmental thermal stress, especially during the summer when air temperature and humidity are very high. Using Microalgae as an alternative feedstuff can significantly improve sheep growth, health and oxidative status. Therefore, this study aimed to evaluate the effect of consuming two different species of microalgae: Spirulina platensis (SP) and Chlorella vulgaris (C. vulgaris) on the following: growth performance, oxidative status, kidney and liver function, serum Glu, proteins and lipids profile and haematological parameters under hot dry environmental conditions. A total of 32 Ossimi male lambs were divided randomly into four equal groups (n = 8), (G1) was fed the control diet, (G2) was supplemented with S. platensis, (G3) was supplemented with a combination between (S. platensis and C. vulgaris) and (G4) was supplemented C. vulgaris. The results of our study revealed that microalgae supplementation significantly (p ≤ 0.05) enhanced lamb's growth, liver and kidney function, levels of serum immunoglobulin IgG, glutathione peroxidase (GPX) and haematological parameters. Moreover, the levels of thyroid hormones and serum proteins profile were significantly increased in all treated lambs compared to the control group. Our research revealed that including microalgae in sheep's feed can enhance their immune system, promote growth and enhance their general health by mitigating the harmful effects of heat and oxidative stress.

Incoming flow calculation in Nam Theun 2 Reservoir

Laos is a country with a humid tropical climate, consisting of two seasons: the rainy season and the dry season. The southwest monsoon influences the region from mid-May to early October, while the northeast monsoon affects the area from early November to mid-March. Generally, the average annual rainfall ranges from 1400 mm to 2500 mm and exceeds 3500 mm in the central and southern regions. In September 2018, a hydroelectric dam encountered issues, causing part of the dam to collapse in southern Laos, Attapeu province. This disaster resulted in severe damage, with 98 people missing and 6,600 people displaced. In early September 2024, northern Laos experienced sudden flooding in Luang Namtha province, causing significant property damage. Additionally, heavy rainfall influenced by Typhoon Yagi led to the release of water from northern Laos dams for safety, including Nam Tha, Nam Ou, Nam Lik, Nam Khan 2-3, and Xayaburi dams. The issues arose from heavy rainfall and miscalculations in water flow into reservoirs, particularly in dam water management to provide early warning information to downstream communities. The purpose of this study is to assess the accuracy of the Intergrade Flood Analysis System (IFAS) model in calculating water inflow into reservoirs, specifically Nam Theun 2, to support to the water management and prevent flood-related issues. The performance of the IFAS model result used NSE (Nash-Sutcliffe efficiency), PBIAS (percent bias), R2 (coefficient of determination), and RSR (root mean square error) to compare calculated by IFAS and the water balance from 2010 to 2024, with results of NSE = 0.58, PBIAS = 8.79, R2 = 0.68, and RSR = 0.65. The 2023 study showed the highest accuracy with NSE = 0.73, PBIAS = -12, R2 = 0.83, and RSR = 0.52, Ev = 9.6 % The findings concluded that the IFAS model can calculate daily water inflow but has limitations in calculating peak and the extreme climate dry condition, such as in 2020 and 2022.

Osteogenic differentiation of mesenchymal stem cell on poly sorbitol sebacate scaffold under shear stress in a bioreactor.

Mechanical loading plays a pivotal role in regulating bone anabolic processes. Understanding the optimal mechanical loading parameters for cellular responses is critical for advancing strategies in orthopedic bioreactor-based bone tissue engineering. This study developed a poly (sorbitol sebacate) (PSS) filmscaffold with a sorbitol-to-sebacic acid molar ratio of 1:4. The scaffold underwent extensive characterization, including physical and mechanical property evaluations, biocompatibility assessments, and cell adhesion analysis. The Young's modulus of the PSS polymer was determined to be 6.81 ± 0.44 MPa under dry conditions, 6.37 ± 1.09 MPa in a wet state, and 6.38 ± 0.71 MPa after ethanol washing (70 %). The average contact angle of the PSS film was measured at 88.806 ± 1.644°, indicating moderate hydrophilicity. To investigate the osteogenic potential, a fluid flow inducing a shear stress of 1 Pa at a frequency of 1 Hz was applied to mesenchymal stem cells (MSCs) cultured on the PSS scaffold. Cells were exposed to dynamic fluid flow for one hour daily on days 4, 5, 6, and 7 of culture, followed by a static culture period of 14 days. The expression of osteogenic differentiation markers, including osteopontin (OPN), osteocalcin (OCN), type I collagen, and calcium deposition, was significantly elevated under dynamic conditions compared to static culture. This study highlights the importance of mechanical stimulation in enhancing MSC osteogenesis and underscores the osteoconductive properties of the PSS scaffold. These findings provide valuable insights into scaffold design and mechanical loading strategies for laboratory-based bone tissue engineering applications.

Trends and Spatiotemporal Patterns of the Meteorological Drought in the Ili River Valley from 1961 to 2023: An SPEI-Based Study

Drought presents significant challenges in arid regions, influencing local climate and environmental dynamics. While the large-scale climatic phenomena in Xinjiang, northwest China, are well-documented, the finer-scale climatic variability in subregions such as the Ili River Valley (IRV) remains insufficiently studied. This knowledge gap impedes effective regional planning and environmental management in this ecologically sensitive area. In this study, we analyze the spatiotemporal evolution of drought in the IRV from 1961 to 2023, using data from ten meteorological stations. The SPEI drought index, along with Sen’s trend analysis, the Mann–Kendall test, the cumulative departure method, and wavelet analysis, were employed to assess drought patterns. Results show a significant drying trend in the IRV, starting in 1995, with frequent drought events from 2018 onwards, and no notable transition year observed from wet to dry conditions. The overall drought rate was −0.09 per decade, indicating milder drought severity in the IRV compared to broader Xinjiang. Seasonally, the IRV experiences drier summers and wetter winters compared to regional averages, with negligible changes in autumn and milder drought conditions in spring. Abrupt changes in the drying seasons occurred later in the IRV than in Xinjiang, with delays of 21 years for summer, and over 17 and 35 years for spring and autumn, respectively, indicating a lagged response. Spatially, the western plains are more prone to aridification than the central and eastern mountainous regions. The study also reveals significant differences in drought cycles, which are longer than those in Xinjiang, with distinct wet–dry phases observed across multiple time scales and seasons, emphasizing the complexity of drought variability in the IRV. In conclusion, the valley exhibits unique drought characteristics, including milder intensity, pronounced seasonal variation, spatial heterogeneity, and notable resilience to climate change. These findings underscore the need for region-specific drought management strategies, as broader approaches may not be effective at the subregional scale.

Biome conservatism prevailed in repeated long-distance colonization of Madagascar's mountains by Helichrysum (Compositae, Gnaphalieae).

Colonization and diversification processes are responsible for the distinctiveness of island biotas, with Madagascar standing out as abiodiversity hotspot exceptionally rich in species and endemism. Regardless of its significance, the evolutionary history and diversification drivers of Madagascar's flora remain understudied. Here we focus on Helichrysum (Compositae, Gnaphalieae) to investigate the evolutionary and biogeographic origins of the Malagasy flora. We inferred a highly resolved phylogeny based on target-enrichment data from 327 species (including 51% of Malagasy endemics) and conducted ancestral range estimation analyses. Our results revealed at least six trans-oceanic dispersal events from different African regions to Madagascar during the Pliocene. In this process, biome conservatism prevailed, as evidenced by similarities between Malagasy lineages and their African relatives. The southern African grasslands, known to be the center of diversification and the main source of African Helichrysum lineages, played a key role in the colonization of Madagascar as the ancestral source area of at least three clades. The Tropical Afromontane region was revealed as the source of at least two montane Malagasy lineages that substantially radiated in-situ. Finally, a dispersal event from southwestern Africa led to a lineage represented by a single species adapted to the island's southwestern arid conditions. The main radiations of Helichrysum in Madagascar's mountains occurred within the last 2 My, coinciding with a transition towards cooler and drier conditions and the expansion of open habitats, likely driven by a combination of geographic and ecological speciation. Overall, our findings highlight the affinities between the montane floras of continental Africa and Madagascar.

خصائص التأكل الجاف لأكسدة القوس الصغير المطبقة على سبائك صفائح الماغنيسيوم (31ZA) مع اضافات اللانثانيم

In this research, AZ31 alloys were enhanced with 0.2% and 0.5% La (Lanthanum) using the low-pressure die casting method. These alloys underwent hot rolling at 400°C with speeds of 4.7 and 10 (m/min) meters per minute, Maintaining a deformation rate of 30% with each pass. Post-production, Micro Arc Oxidation (MAO) has been utilized. The durability against wear of the extracted material sheet samples, each having different surface morphologies due to varying La percentages, was investigated under dry conditions following The ASTM G-133 standard method assesses the sliding wear of ball-on-flat surfaces using a linear reciprocating motion. This study conducted a systematic analysis of how the MAO coating and the addition of La influence wear resistance, supported by microstructure analysis. Keywords: AZ31, La, Wear, Hot rolling, MAO.

α-MnO2 catalysts with efficient ozone-catalyzed decomposition under high humidity conditions.

Ground-level ozone pollution poses significant risks to ecosystems and human health and requires effective control measures. This study focused on the monolithic ozone degradation catalyst based on powdered α-MnO2 and comprehensively investigated its catalytic performance, moisture resistance, and stability. The monolithic catalyst achieved the optimal catalytic activity with an ozone conversion rate of 99% after being calcined at 400 °C for 3 hours. The detailed characterization of the catalyst properties at pH = 1, 4, and 7 revealed the adverse effects of residual acid ions on the catalyst activity. The catalyst at pH = 7 had more oxygen vacancies, which was related to the reduction of sulfate ion residues and the exposure of more active sites during the washing process. At pH = 7 and a space velocity of 900 000 h-1, the conversion rates of α-MnO2 to 18 ppm ozone reached 100% and 95% within 3 hours under 90% relative humidity and dry conditions, respectively. In addition, the monolithic catalyst exhibited significant moisture resistance and performed well in continuous alternating humidity cycle tests and sustained high humidity. It still maintained 90% ozone decomposition efficiency after 3 hours of testing under high humidity conditions. Meanwhile, the α-MnO2 monolithic catalyst showed excellent stability, with an ozone conversion rate exceeding 99% during the 50 - hour test period. These findings highlight the great potential of the α-MnO2 monolithic catalyst in ozone removal applications.

Hyperspectral imaging for detection of macronutrients retained in glutinous rice under different drying conditions

Hyperspectral imaging for detection of macronutrients retained in glutinous rice under different drying conditions