Deposition Patterns Research Articles

Evaporation of bacteria-laden surrogate respiratory fluid droplets: On a hydrophilic substrate vs contact-free environment confers differential bacterial infectivity

The transmission of viruses/bacteria causes infection predominantly via aerosols. The transmission mechanism of respiratory diseases is complex, which includes direct or indirect contact, large droplet, and airborne routes apart from close contact transmission. With this premise, two modes of droplet evaporation are investigated to understand its significance in airborne disease transmission; a droplet in a contact-free environment, which evaporates and forms droplet nuclei, and a droplet on a hydrophilic substrate (fomite). The study examines mass transport, the deposition pattern of bacteria in the precipitates, and their survival and virulence. The osmotic pressure increases with the salt concentration, inactivating the bacteria embedded in the precipitates with accelerated evaporation. Furthermore, the bacteria's degree of survival and enhanced pathogenicity are compared for both evaporation modes. The striking differences in pathogenicity are attributed to the evaporation rate, oxygen availability, and reactive oxygen species generation.

Time-varying microplastic contributions of a large urban and industrial area to river sediments

The quantification of microplastic (MP) pollution in rivers is often constrained by a lack of historical data on a multi-decadal scale, which hinders the evaluation of public policies. In this study, MP contents and trends were analyzed in dated sediment cores sampled upstream and downstream of a large metropolis, in environmental deposits that exhibited consistent sedimentation patterns from the 1980s to 2021. After a thorough sedimentological analysis, MPs were quantified in samples by micro Fourier Transform InfraRed spectroscopy (μFTIR imaging) and a density separation and organic matter digestion procedure. Microplastics recorded in the upstream core are relatively ubiquitous all along the dated sequence. The results also confirmed a sever increase of microplastics levels in the downstream core, by one order of magnitude, and an increase of polymer types. Polypropylene, polyethylene, and polystyrene represent ubiquitous contamination and were predominant at the two stations, whereas polyvinyl chloride and polytetrafluoroethylene were suspected to be abundant at the downstream station, but were not detected at the upstream station. Their presence could be linked to local contamination from specific industrial sources that manufactured and utilized these polymers. Surprisingly, in the downstream station sediment has recorded a relative improvement in polymers associated with industrial sources since the 2000s and, to a lesser extent, for ubiquitous ones since the 2010s. This trend of mitigation diverges from that of global assessments, that assume uncontrolled MP pollution, and suggest that European Union wastewater policy and regulation on industrial discharges have positively influenced water quality, and certainly also on MPs. However, the accumulation of microplastics remains high in recent deposits and raises the emerging concern of the long-term management of these reservoirs.

PROCEDURE FOR DETERMINING THE NATURE OF CALCIUM CARBONATE FORMATION ON OILFIELD EQUIPMENT

In the article, the authors propose to use the method of X-ray diffraction analysis (XRD) to establish the nature of the formation of oilfield deposits using of calcium carbonate as an example. It was shown for the first time that comparative diffraction patterns of natural and technogenic carbonate mineral deposits of oilfield equipment differ significantly in the physical broadening of diffraction reflections. In addition, it has been established that the diffraction reflections of technogenic calcite are characterized by shifts to the region of large scattering angles. These facts are taken as the basis for establishing the nature of the formation of carbonate deposits using X-ray diffraction analysis. It has been shown that natural (core) carbonate minerals are characterized by narrow reflections with good resolution of doublet lines, while in minerals formed under borehole conditions, the diffraction maxima are much broader, and low-intensity reflections are not resolved. Precision analysis of diffraction patterns showed that the reasons for such atypical broadenings and shifts of reflections in technogenic mineral deposits are the relatively small sizes of grains — crystallites and high microdistortions of the crystal lattice compared to their natural analogues. It is shown that in order to establish the nature of carbonate deposits of oilfield equipment, it is necessary to measure diffraction patterns of natural and technogenic minerals under the same shooting conditions. Subsequently, the obtained diffraction patterns are analyzed and X-ray diffraction data on the microstructure of the studied minerals are determined. It has been established that in technogenic calcite the crystallite sizes in all arbitrarily selected directions (hkl) are more than 1.6 times smaller than in its natural analogue. The X-ray diffraction method has shown that the average value of microdistortion of the crystal lattice of technogenic calcite is 1.7 times greater than that of its natural analogue. As a result of comparing X-ray diffraction data on the fine structure of mineral deposits of oilfield equipment with those obtained from core material, the nature of the formation of the analyzed minerals is established. To confirm the XRD results, visual studies using scanning electron microscopy (SEM) were also carried out.

Digital elevation model cell size effect on erosion‐deposition simulation using the unit stream power erosion and deposition model in the dry‐hot valley region of Southwest China

AbstractGully erosion is the main source of sediment in watersheds, and the assessment of soil erosion and deposition in gully systems is very important for land utilization and watershed management. Soil erosion and sediment transport are multiscale, and the digital elevation model (DEM) is one of the most important means to study the scale effect of soil erosion and deposition. To clarify the effect of DEM cell size on soil erosion and deposition in gullies, a series of DEMs with cell sizes of 0.5, 0.7, 1, 1.5, 2, 2.5, 3, 4 and 5 m were generated based on detailed field measurements in dry‐hot valley region. Meanwhile, the unit stream power erosion and deposition (USPED) model was chosen to simulate soil erosion and deposition in this study. The results showed that cell size can greatly influence the average slope and aspect of the DEMs, while the accuracy and average elevation of the DEMs were only affected intensively when the cell size exceeds 3 m. As for the spatial distribution pattern of soil erosion and deposition, the increase of the DEM cell size could cause a concentration of soil erosion and deposition in main channels while weakening the occurrence on hillslopes, and the spatial proximity of soil erosion and deposition would not change with the DEM cell size. The highly positive correlation in simulation results for soil erosion and deposition was primarily observed in DEM cell sizes range of 0.5 to 2 m and from 3 to 5 m. Meanwhile, a slight increase in DEM cell size would significantly affect the simulated results of soil erosion and deposition based on the USPED model when DEM cell size ranged from 0.5 to 0.7 m, whereas the change in DEM cell size would not affect the simulation results when DEM cell size was greater than 0.7 m.

Influence of temperature and pressure gradient on power deposition and field pattern in High Magnetic field Helicon eXperiment

AbstractBased on High Magnetic field Helicon eXperiment, considering the parabolic distribution and Gaussian distribution of radial plasma density, HELIC code was used to study the influence of temperature and pressure gradient on power deposition, electric field, and current density of Helicon Wave Plasma. Three different gradients (positive, negative, and zero gradient) were selected. The results show that positive temperature gradient is beneficial to increase the relative absorption power at the center of plasma. Compared with negative and zero pressure gradients, positive pressure gradient increases the relative absorption power and weakens the current density at the center of plasma, and increases the electric field intensity at the edge of plasma. Larger edge heating will cause the relative absorption power at edge to rise rapidly, which is not conducive to the coupling at the center of plasma. In practical experiments, it is particularly important to reduce the heating effect at edge by cooling the antenna itself. Three different gradients of temperature and pressure have little effect on electric field intensity and current density in plasma, and the variation trend is basically similar, which proves the stability of the antenna mode: m = 1.

Effects of polypropylene microplastics on carbon dioxide dynamics in intertidal mangrove sediments

Microplastics (MPs) in soil can influence CO2 dynamics by altering organic carbon (OC) and microbial composition. Nevertheless, the fluctuation of CO2 response attributed to MPs in mangrove sediments is unclear. This study explores the impact of micro-sized polypropylene (mPP) particles on the carbon dynamics of intertidal mangrove sediments. In the high-tide level sediment, after 28 days, the cumulative CO2 levels for varying mPP dosages were as follows: 496.86 ± 2.07, 430.38 ± 3.84 and 447.09 ± 1.72 mg kg−1 for 0.1%, 1% and 10% (w/w) mPP, respectively. The CO2 emissions were found to be increased with a 0.1% (w/w) mPP level and decreased with 1% and 10% (w/w) mPP at high-tide level sediment, suggesting a tide level-specific dose dependence of the CO2 emission pattern in mangrove sediments. Overall, results indicated that the presence of mPP in mangrove sediments would potentially affect intertidal total CO2 storage under given experimental conditions.

Determining sediment deposition dynamics influenced by check dams in a semi‐arid mountainous watershed

AbstractSemi‐arid environments are characterized by infrequent large magnitude rainfalls that produce flash flood events with high sediment concentration. Control structures such as check dams are widely used in this environment for mitigation. However, their impact on the overall sediment balance of watersheds, particularly those severely affected by anthropogenic activity, is sparsely documented. This study used topographic measurements, sediment analysis, and fallout isotope techniques to assess the effectiveness and service life of 18 rock and masonry check dams that were constructed in the 1930s for controlling sediment fluxes in an 11 ha mountainous watershed in southern Arizona. All of the dams are currently filled with sediment resulting in reduction of local channel gradients by 35 to 71% to between 0.04 and 0.28 depending on location within the reach. Sedimentation occurred over multiple decades at a relatively slow average rate of 0.59 t ha−1 y−1 indicating low instantaneous retention efficiency. The smaller headwater dams were filled soon after construction; however, their share of the overall storage capacity was minor. Although evaluation of 137Cs was an effective method for dating sediment, the 210Pb dating method was not satisfactory because of sediment sorting effects and complex deposition patterns. The abundance of similar control structures in the region points to the opportunity to better understand the process impacts of check dams over multiple decades to inform planning and design of their use in future mitigation projects.

Large wood fluctuation and longitudinal connectivity conditions along a segment of the Blanco River (Chilean Patagonia)

Data collected between 2015 and 2022 was utilised to assess longitudinal connectivity and explain the temporal and spatial fluctuation of large wood (LW) along the Blanco River, which was severely affected by the 2008 eruption of the Chaitén Volcano in southern Chile. The study was performed along a ~ 10.6-km long segment, which was divided into two sub-segments (upper and lower). LW source areas were identified using information from previous research, complemented by the analysis of satellite images to cover the study period. LW fluctuation was studied for the period 2017–2022, using field data and images from an unmanned aerial vehicle along seven 80 m-long reaches located within the lower sub-segment of the river. Using the generated georeferenced orthomosaics and digital elevation models, LW and wood jams (WJs) locations, abundance, dimensions, volumes, and WJs stability were assessed, as well as wood deposition patterns. Streambank erosions and landslides were found to be the main LW sources. Considering wood sourcing, and the variations in the number of LW and WJs, in the dimensions of individual LW and WJs volume and deposition patterns as indicators, it was possible to infer the longitudinal connectivity conditions for the studied segment through time. The results showed that the upper and lower subsegments were poorly connected. However, changes in LW abundance over time, its dimensions and volumes, and the very low stability of WJs, and LW deposition patterns indicative of fluvial transport confirmed that the lower subsegment was longitudinally connected. The results also verified that the presence of LW did not affect water or sediment longitudinal connectivity along the fluvial system. The volume of individual LW and WJs showed a decreasing trend with time in all study reaches. As the bank erosions able to source LW to the channel are also reducing with time, pieces of wood deposited in the active channel may become the only way to sustain LW availability for the next few years. Things could change with the occurrence of an extreme and infrequent flood able to connect the upper and lower sub-segments and force the river to initiate a new phase of planform adjustments.

Lacustrine rhythmites from the Mulhouse Basin (Upper Rhine Graben, France): a sedimentary record of increased seasonal climatic contrast and sensitivity of the climate to orbital variations through the Eocene-Oligocene Transition

The Eocene-Oligocene Transition (EOT) marks the passage from Eocene greenhouse to Oligocene icehouse conditions. It holds keys to our understanding of the behavior of climate systems under major pCO2 shifts. While the environmental impact of the EOT is rather homogenous in oceans, it is much more heterogeneous on continents. Although little to no changes are recorded in some regions, several EOT studies in western Eurasia suggest an increase in seasonal climatic contrast (e.g., higher amplitude of changes in mean temperature or precipitation), along with a higher sensitivity of the climate to orbital variations. However, these variations remain to be properly documented through changes in sedimentary facies and structures and forcing mechanisms. Here we investigate the depocenter of the Mulhouse Basin (Upper Rhine Graben; URG) revealing a prominent transition from massive mudstones to laminated sediments and varves, alongside the emergence of astronomically-forced mudstone-evaporite alternations. These changes are identified in the distal and proximal parts of the southern URG, where they consist of millimeter-thick mudstone-evaporite couplets and siliciclastic-carbonate couplets. The elemental composition and micro-facies analysis of the laminae show a recurrent depositional pattern consistent with a seasonal depositional process, which suggests that they are varves. We propose that the occurrence of varved sediments, together with the observed orbital cyclicity in the southern URG, reflects an increase in seasonal climatic contrast, and an increase in the sensitivity of climate to orbital variations across the EOT. We show that similar changes were noticed in the Rennes and Bourg-en-Bresse basins, and that of other western Eurasian records for similar climatic conditions. This work emphasizes the potential of high-resolution sedimentary structures to serve as markers of climate change across the EOT.

A facies‐constrained geostatistical seismic inversion method based on multi‐scale sparse representation

AbstractGeostatistical seismic inversion is an important method for establishing high‐resolution reservoir parameter models. There is no accurate representation method for reservoir structural features, and prior information about structural features cannot be incorporated into geostatistical inversion. Based on the assumption of the sparsity of stratigraphic sedimentary features, the same type of structural feature is used to represent the sedimentary pattern of reservoirs within the same facies. Different sparse representation patterns are used to represent the differences in sedimentary patterns between facies. Although changes in depositional environment might result in the multi‐scale characteristics of geological structures for varying sedimentary rhythms, this paper proposes a facies‐constrained geostatistical inversion method based on multi‐scale sparse representation to better accommodate such situation. Using the method of sparse representation combined with wavelet transform, the multi‐scale sedimentary structural features of reservoirs are learned from well‐logging data. Seismic facies and multi‐scale features are used as prior information for geostatistical inversion. Further, the likelihood function is constructed using seismic data to obtain the posterior probability distribution of reservoir parameters. Finally, the accurate inversion result is obtained by using multi‐scale sparse representation as a constraint in the posterior probability distribution of reservoir parameters. Compared with conventional geostatistical methods, this algorithm can better match the structural features of reservoir parameters with varying geological conditions. Field data tests have shown the effectiveness of this method in improving the accuracy and resolution of reservoir parameter structural features.

Channel morphological change monitoring using high-resolution LiDAR-derived DEM and multi-temporal imageries

Natural processes and human activities both cause morphological changes in channels. Remote sensing products are often used to assess planform changes, but they tend to overlook vertical changes. However, considering both planform and vertical changes is crucial for a comprehensive evaluation of morphological changes. Using spatiotemporal aerial imagery and topographic data, remote sensing plays a vital role in evaluating channel morphological changes and flood-carrying capacity. This study aimed to investigate the morphological changes of a creek in an urban catchment using very high-resolution remote sensing products. In this study, we developed a new framework for investigating overall channel morphology change by employing very high-resolution aerial imagery and a LiDAR-derived digital elevation model (DEM). By digitizing channel boundaries using ArcGIS Pro 3.0, and analyzing various morphological parameters, erosion, and deposition patterns, we examined the impact of urban expansion and infrastructure development on channel adjustments. Channel adjustments have been performed in the case study catchment (Dry Creek, South Australia, Australia) due to urban expansion and development of infrastructure in the downstream reaches. Our findings revealed a significant southwest shift in the planform of the channel, with a maximum shift of 478 m and an average shift of 217 m since 1998. This alteration resulted in an increase in the sinuosity index reaching 1.2. Over the period from 2018 to 2022, the channel experienced a net deposition depth of 3.4 cm to 3.6 cm in downstream reaches. The annual deposition volume in the downstream reaches was 1963 m3, necessitating regular desilting to prevent channel capacity loss and flooding in the surrounding environment. This study also highlights the incremental growth of riparian vegetation within the channel, which affects surface roughness, channel slope, and carrying capacity. These findings provide a valuable baseline for future investigations into stream channel morphology changes and emphasize the importance of implementing appropriate measures such as desilting and vegetation management to mitigate deposition levels, reduce flood risks, and enhance the overall health and functionality of Dry Creek. The framework used in this study can be applied to other case studies employing reliable and high-resolution remote sensing data products.

A comprehensive observation of organic and inorganic nitrogen in gases, particulate matter and precipitation in the northern suburb of Nanjing, East China, with an emphasis on size-resolved particulate nitrogen

China is considered one of the nitrogen deposition hotspots in the world. Measurements to date have focused mainly on inorganic nitrogen, organic nitrogen and the size distribution of particulate nitrogen has yet to be studied. Lack of dry deposition observations imposes a reliance on models, resulting in a much larger uncertainty relative to wet deposition which is routinely measured. In this study, dry and wet organic and inorganic nitrogen deposition were comprehensively measured in Nanjing in 2019, and nitrogen species in size-segregated particles were investigated. Total annual nitrogen deposition flux was up to 29.96 kg N ha−1 yr−1 in Nanjing, with wet deposition contributed slightly more (51.90%) to total deposition than dry deposition (48.10%). Observations revealed that reduced nitrogen (NHx = NH3 + NH4+) contributed 65.49% of the total inorganic nitrogen deposition budget, which implied that the control of reduced N in urban environments is needed to improve local air quality. Dry deposition of ammonia played an especially key role in dry deposition, contributing from 18.17% to 55.91% in different seasons. The deposition flux of water-soluble organic nitrogen (WSON) dominated by wet deposition, with the wet WSON about 4.6 times higher than that of dry deposition and contributed 41.18% of the wet nitrogen deposition. The wet N deposition in summer was significantly higher than in the other three seasons. The seasonal patterns in dry deposition were driven mostly by seasonal concentration patterns. The highest deposition of ammonia occurred in summer, while the deposition of nitrogen dioxide, particulate ammonium and nitrate peaked in winter. The maximum dry and wet WSON deposition appeared in autumn. Higher NH4+ concentration almost distributed in each size bin and centered in ranges of 0.18–1.0 μm, while higher NO3− concentration scattered in particle size ranges of 1.8–5.6 μm and 0.18–1.0 μm.

Multi-scale habitat influences sprainting and group size of a freshwater-obligate smooth-coated otter (Lutrogale perspicillata) in Tungabhadra Otter Conservation Reserve, India

BackgroundThe impact of changing land-use patterns and associated anthropogenic threats on scale-dependent habitat use of semi-aquatic mustelids in scent-marking and social behaviour can provide important insights into the habitat ecology of smooth-coated otters (Lutrogale perspicillata).MethodsWe sampled 180 stream segments (100–400 m) as spatial replicates of 60 1-km2 sites to record indirect evidence (i.e. spraints and mass latrine sites) and group sizes of smooth-coated otters along the Tungabhadra Otter Conservation Reserve (TOCR) during the dry season. To quantify habitat, we recorded stream characteristics, riparian vegetation, and anthropogenic disturbances at the local scale, and hydro-environmental characteristics and land uses at the landscape scale. Using Markovian-chain detection and occupancy models, we assessed the multi-scale habitat use of otters in their selection of suitable areas for scent-marking based on repeated presence-absence data on spraint/latrine locations along the TOCR. We further used linear regression techniques to explore relationships between the number of individuals in smooth-coated otter group and hydro-environmental characteristics, spraint/latrine encounter rate, anthropogenic pressure, land cover, topography, and vegetation.ResultsAt the local scale, the probability of spraint deposition and group size decreased with anthropogenic disturbance while the probability of spraint detections decreased with grass cover. At the landscape scale, the probability of otter site use for spraint deposition and group sizes increased in southeast flowing streams. Spraint deposition increased with the proportion of sugarcane fields, whereas in contrast, group size decreased with proportion of sugarcane fields.ConclusionsOur findings highlight the first empirical evidence on multi-scale habitat use of a southern Indian population of smooth-coated otters in an inland freshwater ecosystem surrounded by the scrub jungle–agriculture matrix. We suggest that habitat models built from analytical approaches that account for correlated detections can avoid biased predictions when estimating occupancy and detection probability of semi-aquatic or riparian mammal communities with linear distributions. Our findings indicate that human activity can impose constraints on the choice of sites used for spraint deposition and preliminary patterns in otter groups. The study provides some crucial evidence on the need to maintain areas with minimal human interference for sustainability of freshwater reserves.

Discussion of the W-Sn-REE Metallogenic Background in the Nanling Region of South China: Evidence from Satellite Gravity and Magnetic Data

The Nanling region is located at the intersection of the Yangtze Block and Cathaysia Block and is characterized by complex geological and tectonic processes, as well as distinct W-Sn-REE mineralization. Despite extensive research on the mineralization of W-Sn and REE deposits in the Nanling region, the factors impacting the distribution pattern of eastern tungsten and western tin deposits, as well as the mechanism of REE enrichment in the parent rocks, remain uncertain. Deep structural and tectonic variability plays a crucial role in the formation of mineral deposits in the upper crust. Information on deep structural and tectonic variability is contained in the Moho depth, Curie depth, effective elastic thickness, lithospheric density, and thermal structure derived from the processing and inversion of satellite gravity and magnetic data. In this paper, we comprehensively analyse satellite gravity and magnetic data from the Nanling region, integrating the processing and inversion results with the tectonic evolution of this region and relevant geological information. It is hypothesized that the Chenzhou–Linwu fault serves as a channel for mineral and thermal transfer in the Sn ore aggregation zone, facilitating the material transport from the deep mantle to the surface and ultimately leading to the formation of Sn-enriched granite. The collection area of tungsten ore is more weakly associated with the Chenzhou–Linwu fault, and through deep heat transfer, tungsten components are primarily concentrated in the Earth’s crust to produce W-enriched granite. The primary source of REE enrichment in the parent rocks associated with REE mineralization is predominantly derived from the felsic crust, and the rapid intrusion of deep magma resulting from the subduction and retraction of the Palaeo-Pacific Plate is a contributing factor to the contrasting enrichment of light and heavy rare-earth elements. Mineral crystalline differentiation is relatively high, leading to the formation of ore-forming parent rocks with high heavy rare-earth element contents.

Field implementation to resist coastal erosion of sandy slope by eco-friendly methods

Coastal erosion is a global issue that not only compresses land space but also undermines offshore structures. In this study, two eco-friendly technologies (microbially and enzyme induced calcium carbonate precipitation) were implemented at a sandy slope field site to enhance erosion resistance. Improvement of the treated sandy slope against erosion was assessed by penetration resistance, calcium carbonate content, cone penetration testing (CPT) results, terrain data and microscopic morphology. Results indicated that the penetration resistance and calcium carbonate content of treated slopes increased first and then decreased over time because of the gradual formation of calcium carbonate and the erosion caused by the marine environment. Calcium carbonate content and penetration resistance presents an obvious linear relationship. The existence of the superficial cemented crust layer increased the water retention capacity of the sand in the atmosphere region. The calcium carbonate content and CPT results in the tidal region shows the characteristics of layered cement. The spherical calcium carbonate cementation improves the roughness and integrity of the terrain, enhances the particle size of the sand, gradually changing the topography from pre-treatment dynamic erosion to depositional patterns. The treated slope still maintained a certain penetration resistance and calcium carbonate content for 60 days until being eroded by the wind in the atmosphere region. However, the effective protection duration in the tidal zone which encounters wind, wave, tide and reflow was about 24 days, and would thus need to be reinforced periodically over time to obtain long-term protection.

Numerical simulation of the transport of breath-exhaled aerosol from manikin with realistic nasal airway over short social distances

This study delves into the dynamics of respiratory droplet dispersion in indoor settings, focusing on three pivotal aspects: the use of Respiratory Models (RM) versus Non-Respiratory Models (NRM), the influence of social distancing, and the size of exhaled droplets. Our advanced simulations reveal that RMs are essential for accurately predicting airflow and droplet trajectories, whereas NRMs tend to overestimate deposition. We further explore how variations in the distance between an infector and a susceptible individual significantly affect droplet behavior and potential transmission. Additionally, our findings highlight the critical role of droplet size in determining their travel and deposition patterns. These insights collectively provide a comprehensive understanding of aerosol transmission in indoor environments, offering valuable contributions to public health strategies aimed at controlling airborne diseases.

Effects of vegetation density on flow, mass exchange and sediment transport in lateral cavities

Large-Eddy Simulations (LES) were used to investigate the hydrodynamics and mass transfer between the flow in the main channel and a vegetated lateral cavity. Fourteen vegetation densities (0 to 10.65 %) were tested, revealing two distinct hydrodynamic patterns. For cavities with low vegetation density (a < 3.99 %), one primary gyre in contact with the interface between main channel and cavity with high velocity was formed; the thickness of the mixing layer grew longitudinally along the interface, and regions with high vorticity and turbulence kinetic energy appeared at the interface and inside the cavity. For cavities with high vegetation density (a > 3.99 %), two gyres in contact with the interface with low velocity were formed, the thickness of the mixing layer did not grow, and the vorticity and turbulence kinetic energy were low inside the cavity. The mass transport presented the same threshold value as the hydrodynamics (a = 3.99 %). For cavities with low vegetation density, a fast mass transfer occurred through the interface between the main channel and cavity and inside the cavity, while the opposite was observed for cavities with high vegetation density. Finally, the modelled hydrodynamics was used to infer possible sediment deposition patterns and flow resistance.

The Impact of Climate Change on Sultan Dam

The Sultan Dam, located in the Jaghatu District of wardak province of Afghanistan, is a crucial water resource supporting irrigation, hydropower generation, and domestic and industrial water supply. However, the dam is increasingly vulnerable to the impact of climate change. This study assesses the specific impact of climate change on the Sultan Dam during the period of 2015 to 2023. By employing a multidisciplinary approach, including historical climate data analysis, hydrological modeling, and GIS, the study examines changes in water resources, sedimentation patterns, and reservoir dynamics. The analysis focuses on climate change-related effects such as shifts in precipitation patterns, temperature variations, and changes in the frequency and intensity of extreme weather events like droughts and floods. The findings highlight the significant challenges faced by the dam and its water resources due to climate change such as a lack of water capacity, the collapse of the wall of sultan dam, lack of agricultural products, heavy rains, increase of floods and soil erosion and so on. Recommendations include enhancing water management practices, upgrading dam infrastructure, and integrating climate-informed operations. Incorporating an integrated water resource management approach, promoting public awareness, and investing in ecological restoration efforts are crucial for improving the dam's resilience and ensuring sustainable water availability. The study's outcomes provide valuable insights for policymakers, decision-makers, and researchers working towards effective climate change adaptation strategies for the Sultan Dam and similar water resources in the region.

Enhancing Inhalation Drug Delivery: A Comparative Study and Design Optimization of a Novel Valved Holding Chamber.

This paper presents an innovative approach to the design optimization of valved holding chambers (VHCs), crucial devices for aerosol drug delivery. We present the design of an optimal cylindrical VHC body and introduce a novel valve based on particle impaction theory. The research combines computational simulations and physical experiments to assess the performance of various VHCs, with a special focus on the deposition patterns of medication particles within these devices. The methodology incorporates both experimental and simulation approaches to validate the reliability of the simulation. Emphasis is placed on the deposition patterns observed on the VHC walls and the classification of fine and large particles for salbutamol sulfate particles. The study reveals the superior efficacy of our valve design in separating particles compared to commercially available VHCs. In standard conditions, our valve design allows over 95% of particles under 7 μm to pass through while effectively filtering those larger than 8 μm. The optimized body design accomplishes a 60% particle mass flow fraction at the outlet and an average particle size reduction of 58.5%. When compared numerically in terms of size reduction, the optimal design outperforms the two commercially available VHCs selected. This study provides valuable insights into the optimization of VHC design, offering significant potential for improved aerosol drug delivery. Our findings demonstrate a new path forward for future studies, aiming to further optimize the design and performance of VHCs for enhanced pulmonary drug delivery.

Programming crack patterns with light in colloidal plasmonic films

Crack formation observed across diverse fields like geology, nanotechnology, arts, structural engineering or surface science, is a chaotic and undesirable phenomenon, resulting in random patterns of cracks generally leading to material failure. Limiting the formation of cracks or “programming” the path of cracks is a great technological challenge since it holds promise to enhance material durability or even to develop low cost patterning methods. Drawing inspiration from negative phototropism in plants, we demonstrate the capability to organize, guide, replicate, or arrest crack propagation in colloidal films through remote light manipulation. The key consists in using plasmonic photothermal absorbers to generate “virtual” defects enabling controlled deviation of cracks. We engineer a dip-coating process coupled with selective light irradiation enabling simultaneous deposition and light-directed crack patterning. This approach represents a rare example of a robust self-assembly process with long-range order that can be programmed in both space and time.