Significant Fluctuations Research Articles

Risk assessment from radon in domestic water for the Greek population.

This study focused on assessing the risk from the exposure to radon contained in domestic water for a significant part (~20%) of the Greek population. Also, the variation of radon in domestic water was monitored from 2017 to 2023 in certain villages that showed relatively high radon levels and relied on boreholes for their water supply. The radon in domestic water activity concentrations measured in the investigated Greek places ranged from lower than the minimum detection limit (2BqL-1) levels up to 187BqL-1 with an average value of 9.1BqL-1. Overall, higher radon in domestic water activity concentrations were observed in places supplied from boreholes located inside granitic and metamorphic rock areas. Only one out of the 487 examined places, which accounts for 0.015% of the examined Greek population, showed an average radon-in-water activity concentration higher than the parametric value of 100BqL-1 adopted by Greece following the EURATOM Directive (2013/51/EURATOM). Therefore, radon-in-water does not pose a health concern (risk) for the investigated Greek population. The total (inhalation and ingestion) annual effective doses to adults, corresponding to the measured radon-in-water activity concentrations, ranged from nearly 0 to 1.20mSv y-1 with an average value of 0.059mSv y-1, while for children, they ranged from almost 0 to 1.26mSv y-1 with an average value of 0.061mSv y-1. Regarding the variation of radon in domestic water monitoring, places supplied with water from one borehole showed no significant fluctuations from their average radon-in-water activity concentration, with standard deviations of ~20% at a coverage factor of k=1. Even though some places supplied from three to four boreholes showed no significant fluctuations (standard deviation <= 30% at k=1) from their average radon level, special attention is needed for places supplied from many boreholes when one measurement over the year is to be performed for the annual effective dose assessment. This is because the prevailing during-year borehole combination may not exist on the measurement day, resulting in an underestimated or overestimated dose assessment. Radon removal from domestic water supplies in the Arnea village (due to elevated radon-in-water activity concentrations) did not affect the inhalation risk for the residents of an examined house in Arnea. However, radon removal from the water supply was essential to reduce the ingestion risk for the house occupants. There is a possibility of radiation overexposure (>20mSv y-1) for the workers in a thermal spa on Ikaria Island, and further investigation needs to be conducted with extended measurement periods.

Commercial resources of saffron cod &lt;i&gt;Eleginus gracilis&lt;/i&gt; in the Russian waters of the Far-Eastern Seas

Saffron cod Eleginus gracilis, being a typical representative of the elittoral ichthyocene, is an important commercial species in the coastal areas of the Far-Eastern Seas. Small- and medium-sized vessels equipped with both active fishing gears as Danish seine or trawl and fixed nets are used for fishery of this species, it is also popular for amateur and sport fishing from the sea ice. The portion of saffron cod in the total landing is the largest in the Karaginsky fishing subzone (8.1 %) and West-Kamchatka fishing subzone (3.6 %). Annual catch of the species in the Far-Eastern Seas fluctuated in 2003–2022 from 16.7 . 103 to 50.6 . 103 t, on average 33.9 . 103 t. The bulk of this value was caught in the waters at Kamchatka, mostly at its western coast where the average catch was 10.5 . 103 t annually in the last decade. The main fishing grounds of saffron cod are located within the Kamchatka-Kuril, West-Kamchatka, East-Sakhalin and Karaginsky fishing subzones, whereas the stocks at Primorye and sparsely populated coasts of the western Okhotsk Sea and northwestern Bering Sea are underexploited. The saffron cod CPUE reaches 4.5 t per hour of trawling on the shelf of West Kamchatka. The biomass of saffron cod is estimated recently as 197.4 . 103 t in the West-Kamchatka subzone, 100.4 . 103 t in the Karaginsky subzone, 32.8 . 103 t in the West Bering Sea fishing zone, 17.2 . 103 t in the Petropavlovsk-Commander subzone, 17.1 . 103 t in the East-Sakhalin sunzone, and 8.7 . 103 t in the North Okhotsk Sea subzone. The species is distinguished by significant fluctuations of commercial stocks caused by both environmental impacts on its recruitment and fishing pressure. The strong year-classes appear usually in relatively warm or moderate environmental conditions. In modern times, abundance and biomass of almost all exploited stocks of saffron cod in the Far-Eastern Seas excess their average long-term level or fluctuate around, so the state of their populations is considered as quite satisfactory.

Boron Neutron Capture Therapy: Microdosimetry at Different Boron Concentrations

This paper explores the role of microdosimetry in boron neutron capture therapy (BNCT), a cancer treatment involving the selective accumulation of boron-containing compounds in cancer cells, followed by neutron irradiation. Neutron interactions with 10B induces a nuclear reaction, releasing densely ionizing particles, specifically alpha particles and recoiling lithium-7 nuclei. These particles deposit their energy within a small tissue volume, potentially targeting cancer cells while sparing healthy tissue. The microscopic energy distribution, subject to significant fluctuations due to the short particle range, influences treatment efficacy. Microdosimetry, by studying this distribution, plays a crucial role in optimizing BNCT treatment planning. The methodology employs paired tissue equivalent proportional counters (TEPCs), one with cathode walls enriched with boron and the other without. Precise assessment of boron concentration is essential, as well as the ability to extrapolate results to the actual 10B concentration within the treatment region. The effective 10B concentrations within four boronated TEPCs, containing 10, 25, 70, and 100 ppm of 10B, have been determined. Results show variations of less than 3% from nominal values. Additionally, dose enhancement due to BNC interactions was measured and found to be proportional to the 10B concentration, with a proportionality factor of 7.7 × 10−3 per ppm of boron. Based on these findings, a robust procedure is presented for assessing the impact of BNCT in the treatment region, considering potential variations in boron content relative to the TEPC used.

Continuous casting heat transfer model – The spray cooling control problem

In the steel industry, the continuous casting process is regarded as the second significant technical innovation after the advent of the oxygen steelmaking process. Prevailing thermal conditions are a dominant factor in the quality of the product. The common practice of spray control in which water flow in the sprays is proportional to the casting speed is inadequate to unsteady state conditions during speed changes. The objectives of the present study were twofold. The first was to study the basic principles of spray control. As a required tool, a mathematical model for the thermal field was developed. This model was to be used to simulate the temperature distribution in the strand. The second objective was to use these principles to develop a model for controlling the sprays. The thermal model has been used to analyze the effects of both practices on the surface temperature of the strand. The results have shown that a significant temperature fluctuation can be generated by proportional control and that the new control model realistically predicts the thermal requirements of the strand during changes in casting speed.

Study on operation characteristics of a compact megawatt nuclear power system

A novel compact megawatt nuclear power system with a heat pipe reactor coupled supercritical CO2 Brayton cycle has been proposed. To investigate its transient operational characteristics, this paper conducts open-loop dynamic response analyses and designs control systems for it under the load-following mode and the reactor-following mode. Subsequently, transient operational characteristics analysis of the system under different operating conditions is conducted. The results indicate that under load-following conditions, the rotation speed is highly sensitive to disturbances. The system can achieve a load variation of 0–100 % at a rate of 6 %FP/min, while at higher rates, there may be a decrease in speed due to exceeding the regulating range of the bypass valve. It can also accommodate continuous stepped load variations and operate at any desired load level. Under load rejection conditions, the system experiences significant fluctuations, but it can still maintain a new steady state and keep parameters within a safe range. In reactor-following mode, the system can achieve rapid power changes.

A model for predicting the unsteady hydrodynamic characteristics on the blades of a horizontal axis tidal turbine

Tidal current turbines operate in a highly turbulent environment, which results in significant fluctuations in unsteady loads and consequent fatigue and dynamic failures in the rotor. Therefore, accurate calculation of these unsteady loads is crucial. However, the existing models do not take into account the influence of varying relative blade section thickness on dynamic stall when predicting the unsteady characteristics of horizontal axis tidal turbine (HATT) blades. To forecast the unsteady characteristics of the HATT blades, this study developed a method that considers the influence of relative blade thickness on dynamic stall. The modified Leishman-Beddoes (L-B) dynamic stall model, 3D rotational augmentation model, and steady-state BEM model were combined to predict the unsteady hydrodynamic characteristics of blades by synthesizing the transient inlet velocities induced by waves, shear flow and turbulence. In this method, the static parameters required for the modified L-B dynamic stall model were calculated by XFOIL within a range of small angle of attack (AoA) and then extrapolated to cover the entire range of AoA using the Viterna extrapolation method. The required dynamic parameters were obtained by CFD numerical simulation. This method, that we call HATT-UCPM, can consider both the effects of a single element on the unsteady hydrodynamic characteristics of the blades, as well as the combined effects of shear flow, waves, and turbulence on the blades in the actual marine environment. The accuracy of the method was validate through CFD numerical simulation. The results showed that the proposed method has a high consistency with the numerical simulation results, indicating that it has a good accuracy in the prediction of unsteady characteristics of HATT blades. Finally, the study examined several cases to investigate the impacts of shear flow, waves, and turbulence on the unsteady loads of blades, both individually and in combination.

Safety and efficacy profile of intravitreal ranibizumab vs dexamethasone in treatment of naïve diabetic macular edema.

To compare the safety and efficacy parameters of intravitreal ranibizumab vs intravitreal dexamethasone (IVD) in the treatment of patients with naïve diabetic macular edema (DME) in terms of best-corrected visual acuity (BCVA), central macular thickness (CMT), and possible complications like intraocular pressure (IOP) rise and cataract progression. A hospital-based prospective and comparative study of naïve DME patients was conducted between November 2020 and October 2021 with a minimum follow-up (F/U) period of 6 months. Thirty phakic patients received one dose of IVD implant (Group A) and the other 30 (Group B) received three consecutive monthly doses of ranibizumab. The main exclusion criteria were steroid responders and the presence of ocular inflammation. The mean pre-injection CMT in Group A was 405µ and reduced to 297.07µ at 3 months and 278.35µ at 6 months. Mean increase in logMAR BCVA was 0.55. The mean pre-injection IOP was 16.28 and 17.64 mm of Hg at 6 months. In Group B, the mean pre-injection CMT was 401.07µ and reduced to 276.1µ at 3 months and 292.9µ at 6 months. Mean BCVA increased to 0.37. The mean pre-injection IOP was 17.28 mm Hg and 16.42 mm Hg at 6 months. There was no significant progression of cataract in both groups. The mean decrease in CMT was comparable in both the groups at 6 months F/U with an improvement of BCVA with no significant IOP fluctuation or cataract progression. Hence, IVD appears to be noninferior to ranibizumab in the treatment of naïve DME.

Unraveling the relationship between plant species and physicochemical properties on rhizosphere and rhizoplane fungal communities in alpine wet meadows

BackgroundWet meadows, a type of wetland, are impacted by significant climate fluctuation and human activity, impacting soil microorganisms that play an essential role in ecosystem processes. Understanding the underlying ecological mechanisms and processes of wet meadows depends on the fungal communities associated with the plant roots. We used Illumina MiSeq profiling for amplicon sequencing to determine how environmental factors and elevation affect the fungal communities of the rhizosphere and rhizoplane related to three plant species, Cremanthodium ellisii, Cremanthodium lineare, and Caltha scaposa, in alpine wet meadows.ResultsThe phyla Ascomycota and Basidiomycota dominated the rhizosphere (54.5% and 20.9%) and rhizoplane (51.6% and 36.4%), while the predominant fungal genera in the rhizosphere and rhizoplane were Unclassified fungi, Unclassified Ascomycota, Pseudeurotium, Tetracladium, Vishniacozyma, Rhodotorula, Cadophora, and Penicillium. Mantel test and network analysis revealed that the soil water content (SWC), soil organic carbon (SOC), and total nitrogen (TN) were the primary drivers of fungal communities. However, the influence of microbial biomass C (MBC), pH, microbial biomass N (MBN), and elevation varied. Stochastic assembly processes were dominant in both rhizosphere and rhizoplane fungal communities. FUNGuild functional prediction revealed site-specific variation in the trophic level and guild of plant-root-associated fungal communities. The rhizosphere contained 58.5% saprotrophs, 11.7% pathotrophs, and 12.6% symbiotrophs. In addition, 60.4% of the observed OTUs were arbuscular mycorrhizae, 13.2% were endophytes, 20.9% were ectomycorrhizae, and 1.09% were orchid mycorrhizae. The rhizoplane comprised 51.3% of OTUs linked with saprotrophs, 13.9% with pathotrophs, and 7.92% with symbiotrophs. Moreover, 36.1% of OTUs represented arbuscular mycorrhizae, 25.0% were endophytes, 30.6% were ectomycorrhizae, and 2.77% were ascribed to orchid mycorrhizae in the rhizoplane. The abundance of saprotrophs and pathotrophs in the rhizosphere was highest in C. ellisii at SI and SIII, while symbiotrophs were highest in C. lineare at SIII. Similar variations among the plant species and sites were observed in the fungal functional groups (guilds).ConclusionsIt was concluded that although root compartments significantly influenced the fungal communities in the rhizosphere and rhizoplane, environmental factors and plant types exhibited distinct effects. This study explains how physicochemical properties, plant species, and sites can alter the overall structure and functional repertoire of fungal communities in alpine wet meadows.Graphical

Assessing the dynamic thermal performance of prefabricated wall panels in extreme hot weather conditions

Given the potential for extreme weather conditions to cause significant damage to both property and human life, it is imperative to take action to mitigate the impact of such events. Buildings as one of the main shelters of peoples’ lives become critical to study. Especially, building envelopes components that seal the buildings and act as a barrier between indoor and outdoor environments are imperative to evaluate their thermal performance. Moreover, the incorporation of prefabricated wall panels can play a pivotal role in addressing challenges associated with extreme weather conditions due to their capacity to enhance structural resilience, accelerate construction, and encourage sustainable practices. While prefabricated construction has been shown to offer significant advantages in energy conservation, low-carbon emission, and environmental protection, its thermal performance remains uncertain when subjected to significant temperature fluctuations. Therefore, the objective of this paper is to evaluate the dynamic thermal performance of a prefabricated wall panel under extreme weather conditions. Accordingly, a prefabricated wall panel was tested in an environmental chamber, simulating a heat wave that occurred in Chicago in July 2012. The metrics of Decrement factor (DF) and Time lag (TL) were used to measure the dynamic thermal properties. The results show DF of 0.07 and TL of 8 h indicating when considering thickness as a factor, the tested wall panel exhibits superior dynamic thermal performance compared to the other wall panels from the literature. This study provides valuable insights into the impact of building materials and design on energy efficiency and indoor thermal comfort.

A GEOSPATIAL ANALYSIS ON RIVER DYNAMICS IN UPPER ACTIVE BRAHMAPUTRA-JAMUNA FLOODPLAIN REGION, BANGLADESH

The hydro-geomorphic dynamism of the Brahmaputra-Jamuna River system in Bangladesh poses critical challenges for sustainable river management, given the country's vulnerability to climate change and riverbank erosion. The present study employs a longitudinal analysis of Landsat and Sentinel images from 1988 to 2023, integrated with Remote Sensing (RS) and Geographic Information Systems (GIS), to provide a temporal assessment of the river’s dynamic behavior. Results reveal significant temporal and seasonal fluctuations in the riverbed's spatial extent, dynamism rate, and common area, underlining the system's inherent volatility. Between 1988 and 2023, the riverbed’s area exhibited marked variability, ranging from 237.9537 km² to 365.8552 km². Seasonal evaluations also pinpointed pronounced changes, particularly in pre-monsoon and monsoon periods, revealing substantial variations in dynamism area and rates. The study uncovers intriguing patterns, such as the anomalous high dynamism area in 2020 and the surge in winter dynamism rate in 2022, calling for a deeper inquiry into potential climatic anomalies or anthropogenic influences and the need for ongoing monitoring and adaptive river management, particularly under increased environmental stress from climate change.

Ground water availability assessment for a data-scarce river basin in Nepal using SWAT hydrological model

Abstract Mountainous river basins are expected to experience significant seasonal fluctuations in water supply due to climate change. Thus, hydrological modeling becomes further challenging while accounting for data-scarce mountainous basins observing climate change impacts. In this study, Soil and Water Assessment Tool (SWAT) was used to predict hydrological flow in the Sunkoshi River Basin (SRB) based on daily rainfall and temperature data spanning 36 years. The specific objectives of this study were: (i) to use the SWAT model to simulate the long-term hydrological response, (ii) to generate spatially distributed rainfall–runoff and subbasin-wise water balance components using well-established performance indicators. Calibration and validation at the outlet of the study area were successful, with the values of R2/Nash–Sutcliffe efficiency (NSE) calculated as 0.91/0.82 for monthly data and 0.79/0.73 for daily data. In the validation phase, the values of R2/NSE were 0.91/0.84 for monthly data and 0.82/0.75 for daily data, respectively. This study predicted the average yearly flow and precipitation at the SRB outlet to be 279 m3/s and 368.25 mm, respectively. Approximately, 30% of water loss was attributed to evapotranspiration, 18% to runoff, and 30% to lateral flow. The findings of this study will contribute to water resource management.

Calibration and Experimental Study of a Self-Developed Particle-Number Measurement Instrument

To accurately evaluate the size and distribution characteristics of the emission particles exhausted from in-use motor vehicle engines, we independently developed a condensation particle counter (CPC) known as BHCPC. It was calibrated by conducting the calibration procedures stated in the International Standard ISO 27981. After calibration, we conducted on-site measurements and offline sampling analysis of soot particles exhausted from different engines at a motor vehicle inspection center. The calibration results show that the detection efficiency is 90% when the particle diameter is 20.6 nm and the startup response time of the instrument is 3.53 s. The experiment results show that the self-developed BHCPC demonstrates good consistency in measuring particle-number concentration (PNC) in motor vehicle exhaust, with significant count fluctuations only occurring when PNC is higher than 25,000 P/cc. Under idle conditions, motor vehicles compliant with China VI emission regulations exhibit markedly lower exhaust emission PNC compared to those adhering to China IV emission regulations. Moreover, the results obtained from the offline electron microscope analysis show that fuel content in particle samples significantly decreases as engine speed increases, and a similar variation was also found in particle size. The micro-characteristics of the particle can give potential support to the combustion diagnostics.

Genomic and proteomic analysis of Salmonella Enteritidis isolated from a patient with foodborne diarrhea.

Salmonella is a major cause of foodborne diseases and clinical infections worldwide. This study aimed to investigate the drug resistance, genomic characteristics, and protein expression of foodborne Salmonella in Shanxi Province. We isolated a strain of Salmonella Enteritidis from patient feces and designated it 31A. The drug resistance of 31A against 14 antibiotics was determined using an antimicrobial susceptibility test. Whole-genome sequencing and quantitative proteomic analysis were performed on the 31A strain. Functional annotation of drug resistance genes/proteins and virulence genes/proteins was conducted using various databases, such as VFDB, ARDB, CAZY, COG, KOG, CARD, GO, and KEGG. The focus of this study was understanding the mechanisms related to food poisoning, and the genetic evolution of 31A was analyzed through comparative genomics. The 31A strain belonged to ST11 Salmonella Enteritidis and showed resistance to β-lactam and quinolone antibiotics. The genome of 31A had 70 drug resistance genes, 321 virulence genes, 12 SPIs, and 3 plasmid replicons. Functional annotation of these drug resistance and virulence genes revealed that drug resistance genes were mainly involved in defense mechanisms to confer resistance to antibiotics, while virulence genes were mainly associated with cellular motility. There were extensive interactions among the virulence genes, which included SPI-1, SPI-2, flagella, fimbriae, capsules and so on. The 31A strain had a close relationship with ASM2413794v1 and ASM130523v1, which were also ST11 Salmonella Enteritidis strains from Asia and originated from clinical patients, animals, and food. These results suggested minimal genomic differences among strains from different sources and the potential for interhost transmission. Differential analysis of the virulence and drug resistance-related proteins revealed their involvement in pathways related to human diseases, indicating that these proteins mediated bacterial invasion and infection. The integration of genomic and proteomic information led to the discovery that Salmonella can survive in a strong acid environment through various acid resistance mechanisms after entering the intestine with food and then invade intestinal epithelial cells to exert its effects. In this study, we comprehensively analyzed the drug resistance and virulence characteristics of Salmonella Enteritidis 31A using a combination of genomic and proteomic approaches, focusing on the pathogenic mechanism of Salmonella Enteritidis in food poisoning. We found significant fluctuations in various virulence factors during the survival, invasion, and infection of Salmonella Enteritidis, which collectively contributed to its pathogenicity. These results provide important information for the source tracing, prevention, and treatment of clinical infections caused by Salmonella Enteritidis.

Tailoring Three-Dimensional Cross-Linked Networks Based on Water-Soluble Polymeric Materials for Stable Silicon Anode.

For stable battery operation of silicon (Si)-based anodes, utilizing cross-linked three-dimensional (3D) network binders has emerged as an effective strategy to mitigate significant volume fluctuations of Si particles. In the design of cross-linked network binders, careful selection of appropriate cross-linking agents is crucial to maintaining a balance between the robustness and functionality of the network. Herein, we strategically design and optimize a 3D cross-linked network binder through a comprehensive analysis of cross-linking agents. The proposed network is composed of poly(vinyl alcohol) grafted poly(acrylic acid) (PVA-g-PAA, PVgA) and aromatic diamines. PVgA is chosen as the polymer backbone owing to its high flexibility and facile synthesis using an ecofriendly water solvent. Subsequently, an aromatic diamine is employed as a cross-linker to construct a robust amide network that features a resonance-stabilized high modulus and enhanced adhesion. Comparative investigations of three cross-linkers, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-oxidianiline, and 4,4'-oxybis[3-(trifluoromethyl)aniline] (TFODA), highlight the roles of the trifluoromethyl group (-CF3) and the ether linkage. Consequently, PVgA cross-linked with TFODA (PVgA-TFODA), featuring both -CF3 and -O-, establishes a well-balanced 3D network characterized by heightened elasticity and improved binding forces. The optimized Si and SiOx/graphite composite electrodes with the PVgA-TFODA binder demonstrate impressive structural stability and stable cycling. This study offers a novel perspective on designing cross-linked network binders, showcasing the benefits of a multidimensional approach considering chemical and physical interactions.

What happens in ice age, does not stay in ice age: Phylogeography of Bombus terrestris revealed a low genetic diversity amongst the Eurasian populations

The objective of this research was to assess the genetic diversity and phylogeography of Bombus terrestris and examine the historical events that shaped its contemporary genetic structures using the COI mitochondrial marker. Specimens of the species were collected from its distribution range alongside the Alborz Mountain range, and GenBank sequences from the Eurasian distribution range were incorporated into the dataset. The COI sequences were employed in Bayesian and Maximum Likelihood analyses to generate phylogenetic trees for the species populations and to investigate the evolutionary history of the species. Additionally, species occurrence points and climate data were utilized in Species Distribution Modeling (SDM) analyses to reconstruct the species range under past, present, and future climate conditions. The ML and BI trees yielded similar topologies, indicating extremely low genetic diversity and a homogeneous structure in the species population distribution range in Eurasia. Demographic analyses suggested that the species may have experienced a bottleneck during the last glacial maximum in Eurasia, followed by a recent expansion. The SDM analyses revealed significant fluctuations in the species range in the past and expansion under present conditions. Given the high dispersal ability of the species, the population expansion rate has surpassed the rate of developing new genetic diversity, and the estimated polymorphic sites for the species are likely relatively recent. This low level of genetic variation can also be attributed to the absence of geographical barriers and the excellent flying ability of the queen bee, leading to sustained gene flow throughout the entire continent. Despite the general correlation between larger populations and higher genetic diversity, bumblebees can expand their population size without increasing genetic diversity when residing in resourceful habitats.

Entanglement-enabled decoherence-free transmission of two-color photons through a single mode fiber.

We demonstrate decoherence-tolerant transmission of a Bell state through a single-mode fiber (SMF) using the photon frequency degree of freedom. To this end, a slightly non-degenerate polarization-entangled singlet, |Ψ -⟩=(|HV⟩-|VH⟩)/2, is localized at the SMF as the depolarization channel subject to random noise due to incessant fiber bending. Two-photon beats and quantum state tomography jointly verify the absence of collective decoherence, showing that |Ψ -⟩ is the sought-after one-dimensional decoherence-free subspace (DFS) pertaining to SMF. Efficient splitting and combining of photon streams in our DFS help outperform the DFS in time domain. This motivates us to attempt DFS-enabled fault-tolerant fiber transmission of biphoton qubits. Two-photon BB84 protocol is implemented in a polarization-maintaining fiber to which dephasing noise is relevant so that a two-dimensional DFS is appropriate. A low bit error rate 5.4% is achieved by encoding one-qubit information onto the biphoton state in spite of significant polarization fluctuation. Our scalable frequency-based DFS has a natural affinity for wavelength division multiplexing in fiber communication by design and as such is extensible to multi-particle entanglement.

Demand Prediction of Shared Bicycles Based on Graph Convolutional Network-Gated Recurrent Unit-Attention Mechanism

Shared bicycles provide a green, environmentally friendly, and healthy mode of transportation that effectively addresses the “final mile” problem in urban travel. However, the uneven distribution of bicycles and the imbalance of user demand can significantly impact user experience and bicycle usage efficiency, which makes it necessary to predict bicycle demand. In this paper, we propose a novel shared-bicycle demand prediction method based on station clustering. First, to address the challenge of capturing patterns in station-level bicycle demand, which exhibits significant fluctuations, we employ a clustering method that combines graph information from the bicycle transfer graph and potential energy. This method aggregates closely related stations into corresponding prediction regions. Second, we use the GCN-CRU-AM (Graph Convolutional Network-Gated Recurrent Unit-Attention Mechanism) model to predict bicycle demand in each region. This model extracts the spatial information and correlation between regions, integrates time feature data and local weather data, and assigns weights to the input features. Finally, experimental results based on the data from Citi Bike System in New York City demonstrate that the proposed model achieves a more accurate demand prediction.

Analysis of the stability of the Kuban river landslide slope involving the materials of landslide hazard monitoring

The article discusses the improvement of methods for calculating the landslide threat in the monitoring of landslide hazard areas on the Kuban River and the study of the possibility of their negative impact on the operated hydraulic structures. The growth of economic activity, intensive use of water resources in the Kuban River basin leads to a decrease in the bearing capacity of slopes and an increase in landslide phenomena. These processes are also observed in the basins of other anthropogenically developed rivers of the Russian Federation. Shore protection structures and their construction are justified on the basis of the limit state method in accordance with the requirements of SR 58.13330.2011. The stability of such structures should be determined by reference to the stability conditions of the entire slope taking into account all acting loads and impacts. To solve this problem it is very effective to use a complex of structures regulating the flow of the river, flow guides (dams made of selected rockfill), slope-strengthening ones, etc. Measures justifying economic activity on a landslide slope are very effective. The right slope of the Kuban River in the suburbs of Armavir, Krasnodar Krai is characterized by the fact that significant (more than 3 m) fluctuations in inter-level and flood flow of rare frequency are observed on this section of the river. Realizing anti-landslide and bank strengthening measures it is necessary to provide for both a reduction in general and local erosion of the left bank and the drainage of groundwater and surface from the anthropogenically developed area adjacent to the right slope of the river Kuban. The purpose of this research is to substantiate the stability of the right slope of the Kuban River in the vicinity of the city of Armavir, Krasnodar Krai, where initial collapses are already taking place in connection with the construction of residential buildings in the immediate vicinity of the bank and the development of general and local erosion of the right bank of the river. The calculation is carried out according to several methods for the basic and special load combinations. These calculations are necessary to substantiate landslide and bank protection measures on the right bank of the Kuban River.

Photochemical Modification of the Extracellular Matrix to Alter the Vascular Remodeling Process.

Therapeutic interventions for vascular diseases aim at achieving long-term patency by controlling vascular remodeling. The extracellular matrix (ECM) of the vessel wall plays a crucial role in regulating this process. This study introduces a novel photochemical treatment known as Natural Vascular Scaffolding, utilizing a 4-amino substituted 1,8-naphthimide (10-8-10 Dimer) and 450 nm light. This treatment induces structural changes in the ECM by forming covalent bonds between amino acids in ECM fibers without harming vascular cell survival, as evidenced by our results. To further investigate the mechanism of this treatment, porcine carotid artery segments were exposed to 10-8-10 Dimer and light activation. Subsequent experiments subjected these segments to enzymatic degradation through elastase or collagenase treatment and were analyzed using digital image analysis software (MIPAR) after histological processing. The results demonstrated significant preservation of collagen and elastin structures in the photochemically treated vascular wall, compared to controls. This suggests that photochemical treatment can effectively modulate vascular remodeling by enhancing the resistance of the ECM scaffold to degradation. This approach shows promise in scenarios where vascular segments experience significant hemodynamic fluctuations as it reinforces vascular wall integrity and preserves lumen patency. This can be valuable in treating veins prior to fistula creation and grafting or managing arterial aneurysm expansion.

Designing Parameters to Reshape the Inverter Output Impedance Based on the D-Split Method under Weak Grid Conditions

Novel energy generation technologies, such as high-permeability wind power and photovoltaic systems, exhibit inherent intermittency, randomness, and volatility. During periods of energy production from these sources, the impedance of the electrical grid frequently experiences significant fluctuations. Consequently, the grid manifests characteristics akin to a weak grid, highlighting the challenges associated with integrating renewable energy sources with variable output profiles. These fluctuations lead to a shift in resonance spikes of the LCL-type filter towards the lower frequency band, consequently impacting the stability of inverter grid connections. To mitigate this issue, the present study introduces a novel approach integrating the D-split method and a proportional–differential feedforward strategy. This combination aims to reshape the inverter’s output impedance, ensuring its consistent stability even amidst significant fluctuations in grid impedance. In this research, the optimal controller parameters for systems operating under robust grid conditions are initially determined. This selection process involves the application of the D-split method, supported by graphical visualization. Additionally, the amplitude and phase angle margin tester is employed while considering the system bandwidth as a limiting constraint. Moreover, accounting for the influence of grid impedance, the D-split method is reapplied to ascertain the most suitable values for the proportional–differential feedforward parameters. This adjustment aims to enhance the adaptability of the grid-connected inverter specifically in scenarios characterized by a weak grid. The hardware-in-the-loop (HIL) simulation results demonstrate that despite the presence of harmonics within the grid and a short circuit impedance ratio (SCR) of 3, the inverter maintains grid stability and effectively suppresses harmonics. Moreover, the total harmonic distortion factor (THD) of the grid-connected current remains below 5%.