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Objectives: During the early COVID-19 pandemic, college students had to switch to an online learning and online communication environment facing the chances of information overload, misinformation or conflicting information about COVID-19. This study aims to assess the communication needs that have arisen among college students to shed light on the development of a health communication campaign tailored toward college students. Methods: A series of 10 focus group discussions were conducted with 38 total participants. Each group has 2-6 undergraduate or graduate student participants. Nvivo was used to analyze the transcripts. Results: The students reported that they received conflicting information or misinformation. They requested messages with language that was easy to understand with infographics while being culturally appropriate. They advocated for regular and concise email updates from campus leadership. Most participants also preferred COVID-19 control and prevention information on social media. Conclusion: This study revealed the current status and the needs for health information about COVID-19 prevention and control among college students. [ABSTRACT FROM AUTHOR]

In this study, the focus is on the reduction of channel attenuation through diversity techniques. The effectiveness of the diversity system was evaluated based on its ability to lower the carrier noise ratio (CNR) and carrier-to-interference ratio (CIR) at a specific probability of error (Pe). The analysis concentrated on statistically reducing the fading dynamic range of the average CNR and CIR. The aim was to examine two branches (N=2) of diversity systems that employed pre-detection combining, a highly advantageous and effective method in radio mobile communications. The initial phase of the research involved investigating the statistical properties of CNR and CIR without diversity using a Rayleigh fading model. Diversity was then introduced into the experiment. Maximal ratio (MRC) combining, Equal gain (EGC) combining and Selection (SC) combining were simulated and compared. The results showed that the use of diversity techniques significantly reduced the fading dynamic range of the instantaneous CNR γ compared to the instantaneous CIR λ of about 10-3dB Furthermore, maximal-ratio combining (MRC) demonstrated the highest level of performance improvement compared to other methods. [ABSTRACT FROM AUTHOR]

Thin-walled channel beams such as cold-formed steel purlins are primarily used to withstand wind forces in the roofing and walling systems of buildings. Traditionally, these types of members are usually designed for bending moments, with the effects of torsion ignored. However, the loading on thin-walled channels can be much more complicated than simple bending actions. Because of the position of the shear centre outside the section, channels can undergo bending and torsion when subjected to vertical load on the top flange. The applied torsion may cause significant stresses in the channel, which may need to be accounted for in design. There appears to be no research on quantifying the effects of torsion on thin-walled channels subjected to a uniformly distributed load acting on the top flange. In this paper, a theoretical solution is derived for calculating the longitudinal stresses in thin-walled channels subjected to torsion caused by a uniformly distributed load acting on the top flange. The theory is validated by modelling the channels in a finite-element analysis. The theoretical results include calculations of the twist rotation, bimoment, sectorial coordinate and longitudinal stresses, while the results from the finite-element analysis include the twist rotation and longitudinal stresses. The results show that the longitudinal stresses caused by torsion can significantly exceed those caused by the bending moment. Practical advice is also given for engineers on how to minimize torsion in cold-formed steel purlins. [ABSTRACT FROM AUTHOR]

Copyright of Cybernetics & Systems Analysis / Kibernetiki i Sistemnyj Analiz is the property of V.M. Glushkov Institute of Cybernetics of NAS of Ukraine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, there has been a compelling need to adopt cold‐formed ultra‐high‐strength steel (CFUSS) in the construction industry owing to its numerous advantages, such as a higher strength‐to‐weight ratio, flexibility in achieving desired shapes, and adaptability over longer spans. Among the various applications, CFUSS lipped channel sections are commonly used as purlins and joists in steel structural systems. However, these sections are susceptible to different failure modes, particularly web crippling, which presents significant challenges. Currently, the current design rules lack specific guidelines for estimating the web crippling capacity of CFUSS sections. To address this crucial gap, the present study focuses on a comprehensive numerical investigation of the web crippling response of CFUSS lipped channel sections under interior‐two‐flange (ITF) loading conditions. Finite element (FE) models were developed using the ABAQUS package, verified against published test data, and subsequently used in an extensive parametric study. The ultimate web crippling capacity obtained from the parametric study was used to evaluate the accuracy of the current design equations in various design standards. The findings revealed that the existing design equations inadequately predicted the ultimate web crippling capacity of CFUSS lipped channel sections subjected to the ITF loading condition. Consequently, a modified design equation is proposed, utilizing the same approach as the current design standards, and a new direct strength method (DSM) approach is developed and verified through reliability analysis. The proposed modified design equations offer promising solutions to ensure safer and more reliable design practices for CFUSS structures in the construction industry. [ABSTRACT FROM AUTHOR]

Sewage pipes are important conduits for microplastics into the natural environment, but previous studies have paid little attention to the hydraulic characteristics of the confluence of pipe and channel, and the distribution of microplastics at the confluence. This study compared the effects of varying flow rates and particle sizes (Including 500 μm, 700 μm, and 900 μm) on microplastic migration and distribution at the confluence of pipe and channel using experimental measurements. The results obtained using flotation method indicate that flow proportions and particle sizes influence the capacity of flow to transport microplastics. Larger microplastic accumulation occurs in scour holes and separation zones characterized by lower flow velocities, while deposition decreases in acceleration zones characterized by higher flow velocities. Increasing the flow rate of the branch pipe influences the volume of each zone at the pipe-channel confluence. The elongated shape of the scour hole and the acceleration zone facilitate the downstream migration of microplastics. Moreover, the hydrophilic nature of microplastics increases after aging, and it is more likely to migrate to downstream with the water flow, making the downstream microplastics account for more proportion. These results provide valuable insights into the migration and distribution of microplastics at the confluence of pipe and channel, with practical implications for microplastic treatment strategies at these confluences. [ABSTRACT FROM AUTHOR]

Where precision is paramount in managing temperature and fluid dynamics, micro heat exchangers (MHXs) emerge as indispensable tools. This review investigates the significance of MHX technology, offering readers a comprehensive roapmap from conceptualization to market application. We dissect the nuances of material selection, shedding light on cutting‐edge advancements poised to revolutionize MHX efficiency. Furthermore, we explore how the geometry of MHX influences heat transfer dynamics and pressure drop, providing insights into enhancing the overall effectiveness. We delve into the various types of control instrumentation, offering a detailed analysis of their applicability. Beyond the technical prowess, the economic landscape plays a pivotal role in the adoption of MHX technology. [ABSTRACT FROM AUTHOR]

Computational methods such as molecular dynamics (MD) have illuminated how single‐atom ions permeate membrane channels and how selectivity among them is achieved. Much less is understood about molecular permeation through eukaryotic channels that mediate the flux of small molecules (e.g. connexins, pannexins, LRRC8s, CALHMs). Here we describe computational methods that have been profitably employed to explore the movements of molecules through wide pores, revealing mechanistic insights, guiding experiments, and suggesting testable hypotheses. This review illustrates MD techniques such as voltage‐driven flux, potential of mean force, and mean first‐passage‐time calculations, as applied to molecular permeation through wide pores. These techniques have enabled detailed and quantitative modeling of molecular interactions and movement of permeants at the atomic level. We highlight novel contributors to the transit of molecules through these wide pathways. In particular, the flexibility and anisotropic nature of permeant molecules, coupled with the dynamics of pore‐lining residues, lead to bespoke permeation dynamics. As more eukaryotic large‐pore channel structures and functional data become available, these insights and approaches will be important for understanding the physical principles underlying molecular permeation and as guides for experimental design. [ABSTRACT FROM AUTHOR]

In wire electrical discharge machining (WEDM), cutting efficiency is a significant process index whose improvement has always been the research focus. Among the many factors affecting cutting efficiency, discharge energy is the most important factor. Different energy distribution form pulses were obtained by changing the peak currents at single-pulse different discharge stages. Through single-pulse discharge experiments, pulse energy distribution how to impact discharge channel motion characteristics was studied. When the energy distribution is changed through gradually increasing the peak current, an outward-pointing pressure difference will be formed inside the channel, which provides a driving force for the channel to move faster, accelerating the material erosion rate and increasing the discharge crater surface size. The cutting results reveal consistent variations in the cutting efficiency and surface size of individual discharge crater with the pulse energy distribution form. Through changing single-pulse energy distribution, the cutting efficiency can be improved by about 21%. [ABSTRACT FROM AUTHOR]

Visible-infrared person re-identification (VI Re-ID) is designed to perform pedestrian retrieval on non-overlapping visible-infrared cameras, and it is widely employed in intelligent surveillance. For the VI Re-ID task, one of the main challenges is the huge modality discrepancy between the visible and infrared images. Therefore, mining more shared features in the cross-modality task turns into an important issue. To address this problem, this paper proposes a novel framework for feature learning and feature embedding in VI Re-ID, namely Channel Enhanced Cross-modality Relation Network (CECR-Net). More specifically, the network contains three key modules. In the first module, to shorten the distance between the original modalities, a channel selection operation is applied to the visible images, the robustness against color variations is improved by randomly generating three-channel R/G/B images. The module also exploits the low- and mid-level information of the visible and auxiliary modal images through a feature parameter-sharing strategy. Considering that the body sequences of pedestrians are not easy to change with modality, CECR-Net designs two modules based on relation network for VI Re-ID, namely the intra-relation learning and the cross-relation learning modules. These two modules help to capture the structural relationship between body parts, which is a modality-invariant information, disrupting the isolation between local features. Extensive experiments on the two public benchmarks indicate that CECR-Net is superior compared to the state-of-the-art methods. In particular, for the SYSU-MM01 dataset, the Rank1 and mAP reach 76.83% and 71.56% in the "All Search" mode, respectively. [ABSTRACT FROM AUTHOR]

This article focuses on the advancement of fantasy policy solutions to irregular migration, drawing on the case study of the UK/French border. In 2018 people began to cross the English Channel in significant numbers to seek asylum. This led to much commentary and a raft of new legislation seeking to criminalise people crossing the Channel and end rights to seek asylum in the UK. In this article, we explore the interaction between two sets of fantasies that are advanced by politicians and mainstream political parties in the UK. That is: the liberal technocratic fantasy – that this phenomenon can be efficiently 'fixed' through interventions in policing and multilateral cooperation with neighbouring EU states; and the illiberal fantasy that extreme and performative punishments can solve it. These fantasies intersect and break at different points in time, and involve many of the same policy solutions which are represented in different terms. Importantly, both of these fantasies reproduce racialised and colonial logics and ultimately serve border imperialism. [ABSTRACT FROM AUTHOR]

2,4-Difluoronitrobenzene has been reacted with a linker diamine (ethylenediamine or propylenediamine) and butylamine, in either order, to give new molecular building blocks for porous supramolecular networks. Two structures were established by X-ray single crystal structure determinations. The propylenediamine structure displays small pores, which may be due to the longer and more flexible linker in the structure. [ABSTRACT FROM AUTHOR]

A set of exact solutions is suggested for the Poisson equation in a plane region of a certain form for describing a flow of Newtonian incompressible liquid in a channel at low Reynolds numbers. The motion of an ideal liquid in a region bounded by a rotating contour, torsion of a rod, deflection of a membrane at zero displacement on the boundary of its region, and heating of a rod under certain conditions are equivalent to a mathematically formulated problem of such a flow. A possibility is demonstrated to construct approximate solutions to the said problem for certain sections of a channel, having a parabolic segment of the contour, using exact solutions to this problem. Examples are given for the construction of flow regions in a prismatic channel resting on a parabolic contour. [ABSTRACT FROM AUTHOR]

Among the various types of polymeric materials, geosynthetics deserve special attention. A geosynthetic is a product made from synthetic polymers that is embedded in soils for various purposes. There are some basic functions of geosynthetics, namely, erosion control, filtration, drainage, separation, reinforcement, containment, barrier, and protection. Geosynthetics for erosion control are very effective in preventing or limiting soil loss by water erosion on slopes or river/channel banks. Where the current line runs through the undercut area of the slope, the curvature of the arch is increased. If this phenomenon is undesirable, the meander arch should be protected from erosion processes. The combination of geosynthetics provides the best resistance to erosion. In addition to external erosion, internal erosion of soils is also a negative phenomenon. Internal erosion refers to any process by which soil particles are eroded from within or beneath a water-retaining structure. Geosynthetics, particularly geotextiles, are used to prevent internal erosion of soils in contact with the filters. Therefore, the main objective of this review paper is to address the many ways in which geosynthetics are used for erosion control (internal and external). Many examples of hydrotechnical and civil engineering applications of geosynthetics will be presented. [ABSTRACT FROM AUTHOR]

This study examines the flow dynamics and heat transfer characteristics of Maxwell fluid in a channel influenced by magnetohydrodynamics (MHD), Joule heating, thermal radiation, and boundary layer suction/blowing effects. The governing partial differential equations (PDEs) for momentum, energy, and concentration are transformed into ordinary differential equations (ODEs) using similarity transformations. The boundary value problem (BVP) is solved numerically using the bvp4c solver in MATLAB, yielding accurate solutions for velocity, temperature, and concentration profiles under various parameters. Key findings reveal that the porous parameter decreases the velocity profile but increases the temperature profile for both suction and blowing effects. Additionally, the MHD, Deborah, and Eckert numbers significantly influence the velocity and temperature profiles differently under these conditions. This study highlights the crucial role of integrating MHD, thermal, and boundary control effects to optimize performance and efficiency in engineering systems involving Maxwell fluids, with applications in polymer processing, biomedical engineering, electronics cooling, oil recovery, and chemical processing. [ABSTRACT FROM AUTHOR]

The turbidite channel of South China Sea has been highly concerned. Influenced by the complex fault and the rapid phase change of lithofacies, predicting the channel through conventional seismic attributes is not accurate enough. In response to this disadvantage, this study used a method combining grey relational analysis (GRA) and support vector machine (SVM) and established a set of prediction technical procedures suitable for reservoirs with complex geological conditions. In the case study of the Huangliu Formation in Qiongdongnan Basin, South China Sea, this study first dimensionalized the conventional seismic attributes of Gas Layer Group I and then used the GRA method to obtain the main relational factors. A higher relational degree indicates a higher probability of responding to the attributes of the turbidite channel. This study then accumulated the optimized attributes with the highest relational factors to obtain a first-order accumulated sequence, which was used as the input training sample of the SVM model, thus successfully constructing the SVM turbidite channel model. Drilling results prove that the GRA-SVM method has a high drilling coincidence rate. Utilizing the core and logging data and taking full use of the advantages of seismic inversion in predicting the sand boundary of water channels, this study divides the sedimentary microfacies of the Huangliu Formation in the Lingshui 17-2 Gas Field. This comprehensive study has shown that the GRA-SVM method has high accuracy for predicting turbidite channels and can be used as a superior turbidite channel prediction method under complex geological conditions. [ABSTRACT FROM AUTHOR]

Copyright of Coal Geology & Exploration is the property of Xian Research Institute of China Coal Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Two-pore channels are pathophysiologically important Na+-and Ca2+-permeable channels expressed in lysosomes and other acidic organelles. Unlike most other ion channels, their permeability is malleable and ligand-tuned such that when gated by the signaling lipid PI(3,5)P2, they are more Na+-selective than when gated by the Ca2+ mobilizing messenger nicotinic acid adenine dinucleotide phosphate. However, the structural basis that underlies such plasticity and single-channel behavior more generally remains poorly understood. A recent Cryo-electron microscopy (cryo-EM) structure of TPC2 bound to PI(3,5)P2 in a proposed open-channel conformation provided an opportunity to address this via molecular dynamics (MD) simulation. To our surprise, simulations designed to compute conductance through this structure revealed almost no Na+ permeation events even at very high transmembrane voltages. However further MD simulations identified a spontaneous transition to a dramatically different conformation of the selectivity filter that involved expansion and a flip in the orientation of two core asparagine residues. This alternative filter conformation was remarkably stable and allowed Na+ to flow through the channel leading to a conductance estimate that was in very good agreement with direct single-channel measurements. Furthermore, this conformation was more permeable for Na+ over Ca2+. Our results have important ramifications not just for understanding the control of ion selectivity in TPC2 channels but also more broadly in terms of how ion channels discriminate ions. [ABSTRACT FROM AUTHOR]

We embarked on an investigation with potential implications for studying blood flow within the cardiovascular system; keeping this application in mind, this investigation aims to provide numerical evaluations for a complex problem involving MHD flow, chemical reactivity, and energy transfer of a Maxwell fluid within a channel. The governing equations for momentum, concentration, and energy are renovated into ODEs for concentrated analysis using a similarity transformation. Dimensionless velocity, temperature, and concentration fields corresponding to steady motions of Maxwell fluid over a channel are numerically recognized using the bvp4c inbuilt software in MATLAB. We validated our results with existing work to check the gained results and got an excellent agreement. The impression of physical parameters on fluid motion is plotted and debated. The quantitative outcome of this study is that the Deborah number surges, and both velocity and temperature experience enhancement while the concentration within the fluid diminishes. This knowledge can be applied to various fields, such as material processing, biomedical engineering, and environmental sciences, to optimize processes and design systems accordingly. The outcomes and key findings of this study indicate that concentration distribution declines with the introduction of a chemical reaction and a complex Schmidt number. Additionally, the quantitative results of this learning are that the impression of the magnetic parameter is observed, resulting in reduced velocity and temperature profiles, while concentration profiles exhibit an increase across the entire domain. Furthermore, the rise in the Reynolds number corresponds to an escalation in the temperature outline. [ABSTRACT FROM AUTHOR]

Sericulture has a pivotal position in the agricultural production of China. The number of silkworms is one of the key indicators in the process of silkworm breeding, which is crucial to the feeding and healthy growth of silkworms. Accurate detection of the number of silkworms can ensure the quality of sericulture products. However, manual counting has not fully met the needs of large-scale production in recent years. There is a high demand to combine AI technology for silkworm counting. In this study, silkworm detection and counting were studied from the perspective of deep learning. Several challenges were solved in the detection of silkworms. Since the silkworms belonged to the small targets, it was difficult to detect the fewer features; When the number of silkworms was high, serious masking occurred to cause interference in the detection of densely distributed silkworms; It was difficult to ensure that the clear images of silkworms were captured from the actual production. The blur images were easy to deteriorate the accuracy of detection. Two tasks were covered as follows. 1) The image dataset of silkworms was constructed; 2) MAM-YOLO, a silkworm detection and counting model was proposed using multi-dimensional perception. The pictures of silkworms were first taken from the Guangxi Sericulture Technology Promotion Station. These pictures of silkworms were preliminarily processed. The polygon annotation was then selected, according to the body and distribution of silkworms. The pictures of silkworms were annotated with the open-source tool (Labelme). Finally, the dataset was expanded using image transformation and noise addition. The silkworm picture dataset was obtained for the subsequent training, verification, and testing. An improved YOLOv8 (MAM-YOLO) was proposed to detect the silkworm, in order to realize the accurate detection and counting. A silkworm detection and counting model was proposed using space-to-depth transformation and image deblurring. The fine-grained detection performance of blurred images was improved in the MAMYOLO model. The space-to-depth transformed convolution was utilized instead of stride convolution for the pooling layer in the feature extraction. The fine-grained features were extracted from the images, in order to further improve the detection of the low-resolution and small targets. In addition, the impact of blurred images on the detection performance was reduced by introducing a deblurring module into the model. RCS-OSA module was added to the YOLOv8 model. The network feature extraction was improved to integrate the information of different sizes in the receptive fields. The detection head of the original network was improved into the multi-dimensional sensing head. The three-dimensional features of size, space, and channel were aggregated to enhance the detection of silkworm targets. The loss function was replaced with the EIOU loss function. The regression accuracy of the detection frame was improved to reduce the object occlusion. Experimental results show that the MAM-YOLO more accurately detected the silkworm targets. The detection speed of mAP@0.5:0.95 reached 74.8% and 22.2 frames per second, indicating the better functions of silkworm detection and counting with high precision and high rate. The detection requirements were fully met in the actual work of the Guangxi sericulture station. The results show that the silkworm detection and counting system of the technical indicators met the application requirements. The finding can provide the detection services for the actual production work of the silkworm breeding station. In the end, a generalization experiment was conducted on the Global Wheat Challenge 2021 dataset. It was found that the MAM-YOLO was also achieved in the better detection performance of wheat ears, particularly on the small targets similar to dense occlusion.Sericulture has a pivotal position in China's agricultural production. The number of silkworms is a key indicator in the process of silkworm breeding, which is crucial to the feeding and healthy growth of silkworms, and accurate detection of the number of silkworms can ensure the quality of sericulture products. The traditional way of counting silkworms manually is inefficient, and it needs to be combined with technology to intelligently complete this kind of heavy work. In this thesis, from the perspective of deep learning, a silkworm detection and counting method is studied, and several problems in silkworm detection are solved: silkworms belong to small targets, which have fewer features so that they are not easy to detect; silkworms are densely distributed, and when the number of silkworms is high, serious masking phenomenon occurs which causes interference in the detection; it is difficult to ensure that the images of silkworms obtained in the actual production are clear, and blur images will make the detection affected. The main research content of this thesis is as follows: This chapter completed two main tasks: 1) Completed the production of silkworm image data set; 2) MAM-YOLO, a silkworm detection and counting model based on multi-dimensional perception, was proposed.In this paper, pictures of silkworms were taken by workers from Guangxi Sericulture Technology Promotion Station. First, these pictures of silkworms were preliminically processed. Then, according to the characteristics of the body and distribution of silkworms, the polygon annotation method was selected, and the pictures of silkworms were annotated with the open-source tool Labelme. Finally, the data set is expanded by means of image transformation and noise addition, and finally the silkworm picture data set is obtained for subsequent training, verification and testing.This chapter proposes an improved silkworm detection method based on YOLOv8, MAM-YOLO, which realizes accurate detection and counting of silkworm. Secondly, aiming at the problems of loss of fine-grained information and poor detection performance of blurred images in the MAM-YOLO model, a silkworm detection and counting model based on spaceto-depth transformation and image deblurring is proposed. The model utilizes space-to-depth transformed convolution instead of stride convolution and pooling layer in the feature extraction process, so that fine-grained features in the image can be extracted, which further improves the detection capability for low-resolution and small targets. In addition, the impact of blurred images on the detection performance is reduced by introducing a deblurring module into the model. By adding RCSOSA module to YOLOv8 model, the capability of network feature extraction is improved, and the information of different size receptive fields is integrated. The detection head of the original network is improved into multi-dimensional sensing head, and the three-dimensional characteristics of size, space and channel are aggregated to enhance the detection ability of silkworm targets. By replacing the loss function with EIOU loss function, the regression accuracy of detection frame is improved and the problem caused by object occlusion is reduced. Experiments show that MAM-YOLO can more accurately detect silkworm targets, and the detection speed of mAP@0.5:0.95 reaches 74.8% and 22.2 frames per second, which realizes the functions of silkworm detection and counting with high precision and high rate, and can meet the detection requirements in the actual work of Guangxi sericulture station. results show that the silkworm detection and counting system of the technical indicators have met the application requirements, and can provide detection services for the actual production work of silkworm breeding station.In the end, a generalization experiment was conducted on the Global Wheat Challenge 2021 data set, and it was found that MAM-YOLO also showed a high improvement in the detection performance of wheat ears, proving that the proposed method can generalize to other small targets similar to dense occlusion. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the voltage instability in proton exchange membrane fuel cells operating at high current densities, which is important for improving their reliability and durability. Based on experimental findings regarding transparent fuel cells, a method is proposed to identify different types of voltage instability via statistical results of linear changing rate and oscillation amplitude. The types and boundaries of voltage instability are elucidated while evaluating the impact of cathode relative humidity and flow rate on voltage instability. The findings reveal that (1) the voltage instability is greatly influenced by the cathode-side relative humidity and flow rate, (2) there are three typical types of voltage instability: voltage decline, voltage oscillation, and both, and (3) voltage decline occurs at low cathode humidity, while voltage oscillation becomes more severe at large cathode humidity and low flow rate; (4) Reduction of water content in the membrane leads to voltage decline, while an increase in water content in the catalyst layer, gas diffusion layer, and channels leads to voltage oscillation. A full-condition map diagram demonstrating voltage instability during high current density conditions is presented. The method for creating this map for voltage instability will be employed to enhance fuel cell performance. [ABSTRACT FROM AUTHOR]

As an alternative to hydrogen peroxide (H2O2) production by complex anthraquinone oxidation process, photosynthesis of H2O2 from water and oxygen without sacrificial agents is highly demanded. Herein, a covalently connected molecular heterostructure is synthesized via sequential C−H arylation and Knoevenagel polymerization reactions for visible‐light and sacrificial‐agent‐free H2O2 synthesis. The subsequent copolymerization of the electron‐deficient benzodithiophene‐4,8‐dione (BTD) and the electron‐rich biphenyl (B) and p‐phenylenediacetonitrile (CN) not only expands the π‐conjugated domain but also increases the molecular dipole moment, which largely promotes the separation and transfer of the photoinduced charge carriers. The optimal heterostructured BTDB‐CN0.2 manifested an impressive photocatalytic H2O2 production rate of 1920 μmol g−1 h−1, which is 2.2 and 11.6 times that of BTDB and BTDCN. As revealed by the femtosecond transient absorption (fs‐TA) and theoretical calculations, the linkage serves as a channel for the rapid transfer of photogenerated charge carriers, enhancing the photocatalytic efficiency. Further, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) uncovers that the oxygen reduction reaction occurs through the step one‐electron pathway and the mutual conversion between C=O and C−OH with the anchoring of H+ during the catalysis favored the formation of H2O2. This work provides a novel perspective for the design of efficient organic photocatalysts. [ABSTRACT FROM AUTHOR]

An efficient mmWave communication interface requires optimized selection of channel-noise aware transmitter components, noise-reduction amplifiers, low-BER (Bit Error Rate) receiver-components and efficient modulation techniques. A wide variety of such optimization models are proposed by researchers, and each of them very in terms of their internal & external operating characteristics. For instance, channel modelling techniques focus on optimizing transmitter components, while amplifier & de-amplifier design models focus on modulation & demodulation component optimizations. Due to such a wide variation is component designs, it becomes ambiguous for designers to identify optimal models for the context-specific communication interface designs. To reduce this ambiguity, a detailed survey of modern-day mmWave communication interfaces is discussed in this text. This discussion includes analysis of these models in terms of their functional nuances, contextual advantages, application-specific limitations, and deployment-specific future scopes. It was observed that deep learning models & bioinspired optimization techniques outperform others in terms of communication efficiency under real-time use cases. Based on this discussion, readers will be able to observe similar recommendations and identify optimal models for their mmWave communication radio designs. This discussion is further extended via a comparative evaluation of these models in terms of their computational complexity, processing delay, efficiency of optimization, BER levels, and scalability levels. Using this comparison, readers will be able to evaluate these models, and use them for their performance-specific use cases. To further contemplate this discussion, these parameters were combined to calculate a novel Communication Interface Rank Metric (CIRM), which will assist readers to identify micro-level communication interfaces that have higher overall efficiency levels even under different noise and channel conditions. [ABSTRACT FROM AUTHOR]

ABSTRACTThe Kir1.1 (ROMK) family of weak inward rectifiers controls K secretion in the renal CCT and K recycling in the renal TALH. A single point mutant of the inward rectifier, F127V-Kir1.1b was used to investigate the K transition between the selectivity filter and the outer mouth of the channel. We hypothesize that normally an aromatic Phe at the external entryway of Kir1.1b facilitates outward K secretion. We tested this by replacing F127-Kir1.1b with a small aliphatic Val. Results indicate that removal of the Phe at 127 suppresses outward currents that normally contribute to K secretion. Results with the F127V mutant could be explained by increased polyamine block and/or a decrease in the avidity of Kir1.1 for K ions near the outer mouth of the channel. The latter is supported by F127V-Kir1.1b having a lower affinity (Km = 33 mM) for K than wild-type Kir1.1b (Km = 7 mM) during external K elevation. Conversely, chelation of K with 18-Crown-6 ether reduced K conductance faster in F127V (half-time = 6s) than in wt-Kir1.1b (half-time = 120s), implying that F127V is less hospitable to external K. In other experiments, positive membrane potentials gated the F127V mutant channel closed at physiological levels of external Ca, possibly by electrostatically depleting K adjacent to the membrane, suggesting that the Phe residue is critical for outward K secretion at physiological Ca. We speculate that the avidity of wt-Kir1.1b for external K could result from a cation-Pi interaction between K and the aromatic F127.

This study conducts a thorough numerical analysis of a complex problem involving magnetohydrodynamic flow, radiation, activation energy, Soret, the Dufour effect, and heat transfer in a permeable channel for a Maxwell fluid. Governing equations for momentum, concentration, and heat are transformed into ordinary differential equations through a similarity transformation, enabling focused analysis. Utilizing a fourth-order Runge-Kutta scheme, we compute dimensionless velocity, temperature, and concentration fields for the steady motion of a Maxwell fluid in a channel. To ensure accuracy, our results are validated against existing research, showing excellent agreement. The study investigates the impact of various physical parameters on fluid motion, revealing insights such as decreased velocity and concentration with increased chemical reaction, and rising fluid temperature. Additionally, concentration distribution decreases with a chemical reaction and a higher Schmidt number. This research enhances understanding of complex fluid dynamics, providing valuable insights for engineering applications, particularly in industries requiring precise fluid behavior control.

AbstractIn this article, we report the design and fabrication of a ‘do-it-yourself’ microfluidic channel with a circular cross-section, created outside a cleanroom facility. In this approach, the fabrication of the channel do not require any chemical etching or lithography steps, making it safe and suitable for small research groups. The channel is fabricated using the soft-lithography method in polydimethylsiloxane (Sylgard® 184). A copper wire with a diameter of 240 µm is used as a mold, and the channel is created using the wire pull-out method. This work also addresses the optimal use of polydimethylsiloxane in channel fabrication, as well as the challenges faced when connecting the microchannel to the outside world via tubing and techniques to overcome them. All simulations were conducted using COMSOL Multiphysics 6.0. The analytical, simulation, and test results, show a good match.

Background and Objectives: In practice, there are often processes in which in the initial state the working medium is single-phase, for example, in the form of gas (steam), and during the process under study conditions are created for the appearance of a new phase in the form of droplets (nuclei). The process of nucleation and further condensation growth of clusters in supersaturated vapor is one of the most important processes leading to the development of the dispersed phase. The liquid phase nuclei that appear as a result of nucleation are quite small (nano-sized) and, therefore, subject to Brownian wander, which leads to their mutual collisions and coagulation. The processes of evaporation and condensation in various media are used to obtain nanomaterials (in particular, in the synthesis of carbon nanotubes), as well as to obtain nano- and ultradisperse particles in expanding channels due to nucleation and their condensation and coagulation growth. Materials and Methods: Using a quasi-equilibrium model based on the equations of mechanics of multiphase media, the flow of a dispersed mixture in a channel with sudden expansion in the presence of processes of nucleation, coagulation of nuclei (clusters) and phase transitions (evaporation, condensation) in a two-dimensional formulation was studied. The homogeneous nucleation model is used to describe the nucleation process. It is assumed that the process of coagulation of clusters occurs due to their Brownian motion. To determine the rate of phase transitions, the Hertz – Knudsen – Langmuir formula is used. The problem of the flow of a gas-dispersed mixture in a channel with sudden expansion in a twodimensional formulation is considered. It was assumed that in the narrow part of the channel, under certain conditions, nuclei of the dispersed phase continuously appear, which enterthewidened part ofthe channelwiththe flow. The calculationswere carried out based onthe algorithm of the numerical “large particles” method, which is based on splitting the original equations into physical processes. Results: As a result of the study, the basic properties of the flow of a two-phase mixture in a channel in the presence of nucleation, coagulation and phase transitions have been established. It has been shown that the flow has a vortex structure, and the largest particles are formed precisely in the vortex zone. Calculations have established that the coagulation process has a fairly strong effect on the distribution of cluster sizes inside the channel. The influence of the degree of steam supercooling on the flow of the dispersed mixture in the channel has been studied and it has been found that this parameter significantly affects the density distribution of the dispersed phase. The flow pattern obtained using calculations is consistent with experiment. Conclusion: The basic properties of the behavior of the mixture parameters along the expanding channel at presence of nucleation, coagulation and phase transitions have been established. The results obtained can be useful in various areas of modern technology: when designing various heat-power and heat-exchange installations, for studying the process of outflow of various mixtures from containers, for modeling the processes of formation and growth of nuclei (in particular, nanoclusters) in saturated media, etc.

This work investigates the problem of efficient packet scheduling and transmission for IEEE 802.15.4e TSCH based on the Traffic-Aware Scheduling Algorithm (TASA). Three Integer Linear Programming (ILP) formulations are proposed, namely ILP1, ILP2, and ILP3, to comprehensively address key aspects of how packets are optimally delivered from child nodes to the root node, including node parent selection, packet scheduling, and frequency assignment. ILP1 is proposed to model the fundamental operations of TASA including packet scheduling and frequency assignment, while ILP2 further takes node parent selection into consideration for jointly optimizing node parent selection, packet scheduling, and frequency assignment. Despite its superior performance, ILP2 is only applicable to relatively small network problems due to high computational complexity. Therefore, we finally propose ILP3 for fast and efficient node parent selection. ILP3 can be combined with ILP1 and, most importantly, TASA for achieving effective node parent selection atop packet scheduling and frequency assignment for practical TSCH networks. ILP3 combined with ILP 1 led to computational complexity while ILP3 combined with TASA yielded good performance where it required less than one second of execution time and less packet delivery time.

The evolution of wireless communication in the presence of multipath fading and shadowing is generally strained by the worsening of propagation conditions. Thus, in order to estimate the achievable improvements of the link quality (due to channel enhancement), such a parameter as diversity gain is usually used. The diversity gain is classically defined as a limit for infinitely increasing signal-to-noise ratio (SNR) at the receiver input, theoretically attained only in asymptotics, and in practice attained at very high SNR values (e.g., 50–70 dB), which are unrealistic from the practical perspectives for wireless fading channels. In this case, a modified version of the same metric (i.e., the finite-SNR diversity gain; FSDG) was proposed. The presented research performs a comparative analysis of the FSDG for the case of a multipath channel with fading induced by second order scattering and fluctuating line-of-sight (LoS) component (i.e., fluctuating double-Rayleigh with Line-of-Sight; fdRLoS). The signal model included the hexagonal quadrature amplitude modulations (QAM) with regular and irregular constellations. For the considered problem, an exact expression for the FSDG was derived and analyzed as a function of channel parameters (responsible for fading severity and shadowing intensity) and modulation formats. It has been found that the FSDG can exceed the classical (asymptotic) diversity gain by the order of magnitude, and scenarios have been identified where this can occur (for example, the maximum is achieved under conditions of light shadowing and strong line-of-sight component). A nonmonotonic dependence of FSDG on the QAM constellation size (for any type of constellation) was found out: for low-to-moderate average SNR, for extremely weak and extremely strong LoS, the highest FSDG is achieved with smaller constellations, whereas for moderate LoS components, with larger constellations. [ABSTRACT FROM AUTHOR]

The reliable design of multiphase micro‐structured apparatus requires a precise knowledge of the internal flow regime. Previous research indicated that classifiers based on artificial neural networks (ANN) are relatively simple to develop and provide a reasonable accuracy when trained with data for specific inlet designs. This paper introduces advanced ANN classifiers capable of predicting all relevant flow regimes regardless of the inlet design with a recall of 94 % and above for Taylor, churn, dispersed, rivulet, and parallel flows, between 89 % and 94 % for annular and bubbly flows, and 83 % for Taylor‐annular flow. These classifiers were trained and validated by using more than 13,000 experimental data points extracted from 97 flow maps. [ABSTRACT FROM AUTHOR]

The mobile flume has the advantages of not easy to be silted up and can be moved and reused in many places, etc. Compared with the fixed type, the streamlined shape of the measuring flume has good hydraulic performance, and the diffusion section of the flume has a great influence on the hydraulic performance, however, there is a lack of research on the design principle and method of the diffusion section at present. In order to study the influence of flume structure on hydraulic properties, and to provide theoretical guidance for the design of streamlined flume structure, This paper establishes a D40Ushaped channel simulation model, and then uses FLOW-3D to simulate the semi-elliptical with semi-elliptical, semi-elliptical with parabolic, semi-elliptical with arc, semi-elliptical with Myring curve, and fish-shaped flume under flow rates of 35, 45, and 55 L/s. Furthermore, the accuracy effect of numerical simulation is verified by prototype test, and then the design principle and method of diffusion section are discussed. Finally, based on the isight platform, the semi-elliptical with Myring curve and fish-shaped flume with better hydraulic performance are optimized. The results show that the relative error between the numerical simulation and the experimental water depth is 0.1%-1.3% and the relative errors of velocity in upstream, throat and downstream sections are 0.19%-6.63%, 0.06%-6.15% and 0.02%-6.22% at 45 L/s flow rate, respectively. The numerical simulation results have high accuracy. The Froude number in the upstream of the five flumes is less than 0.5, and the maximum backwater height is 5.71 cm, which meets the requirements of flow measurement accuracy and channel safety. Among them, the head loss and backwater height of the semi-elliptical with Myring curve flume are the lowest, the critical submergence degree of the semi-elliptical with semi-elliptical flume is the highest, and the Froude number is the smallest. The design principle of the diffusion section of the flume is: under the condition of slightly reducing the critical submergence degree, the first half of the diffusion section is designed as a curve with larger curvature to reduce the upstream backwater; the second half is designed as a curve with opposite curvature and smaller curvature to improve the flow state, smooth the water flow and reduce the head loss. After optimization, the curvature of the first half of the semi-ellipse with Myring curve and the fish-shape flume increases, and the curvature of the second half decreases, the backwater and Froude number are reduced, and the head loss is reduced by 5.5% and 6.3%, respectively. The study can provide theoretical guidance for the design and optimization of streamlined measuring tank structures. [ABSTRACT FROM AUTHOR]

The micro-channel fabrication in carbon fiber-reinforced polymer (CFRP) composite through electrical discharge machining (EDM) process followed by the comprehensive study of dimensional deviation in the conceived micro-channels are presented in this work. The factors namely, voltage (V), tool rotational speed (TRS), and feed rate (FR) were considered for assessing their impact on channel width deviation (CWD). In addition to the variance analysis,, two potential metaheuristic optimizers, the Butterfly optimization algorithm (BOA) and the Spotted Hyena optimization algorithm (SHO) were used to identify the optimal operating parameters of the aforementioned process. The BOA revealed that the optimal process variables were FR = 5.99 µm/s, V = 150 volt, and TRS = 577.08 rpm for a CWD = 74.96 µm. In contrary, SHO revealed that FR = 5.99 µm/s, V = 150 volt, TRS = 542.96 rpm, and CWD = 74.53 µm were the corresponding optimal values. Overcuts were observed in the fabricated micro-channels and a detailed illustration of the mechanism of overcut formation was provided. [ABSTRACT FROM AUTHOR]

The modern communication network has advanced to such an extent that it is now possible for devices within a wireless personal area network (WPAN) to communicate among themselves directly. However, the limited shared radio resources of a WPAN lead to numerous issues, such as cross-layer interference and data collisions, which wind up affecting the quality of communication. A load based dynamic channel allocation (LB-DCA) model has been proposed to enhance the performance of device-to-device communication in WPAN. This model uses several control schemes in collaboration with interference estimation and channel load balancing mechanisms to allocate and manage the radio resources efficiently. The objective of this model is to achieve high throughput, low interference and low energy consumption. The control schemes implemented are based on distributed coordination and a cell-splitting approach. These schemes are utilized to estimate the channel usage and number of active nodes in a network. The interference estimation is done by using a new efficiency formula. Further, channel load balancing takes into account the hops and load factor values. The proposed model obtained 98.58% CSI, 95.86% MCC, 96.35% delta-P, 97.96% FMI, 99.83% BMI, 21.52% enhanced spectrum efficiency, 16.38% enhanced scalability, 18.79% enhanced signal quality, 18.64% enhanced power control and 18.89% enhanced energy efficiency. [ABSTRACT FROM AUTHOR]

With the advent of fifth Generation of cellular communication with its key features that superior over all the precedent generations. However, there are some challenges need to be taken into consideration. The main crucial part of communication system is the receiver and as it is known there are two main types of receivers which can be used to demodulate the signals and recover the transmitted data. In this paper, we used those two types of algorithm receivers which are the Non-Coherent and Coherent receivers. They are firstly demonstrated in details in accordance with receiver specification design and then moved to the practical side of implementation. In which novelty of our work is highlighted, by carrying out those different algorithms on the ADSP 21364 SHARC board where initially sampling the received DPSK signal, design the Bandpass and lowpass digital filtering respectively and all to be compiled by Analog Devices VisualDSP + + software that is programmed by C language prior to download to the ADSP Board chip. The same algorithm is followed in the frame synchronization for both of them by detecting the message through distinguishing the preamble of the message " + + + + " data which is before the 72 bytes (real message).Then that actual message will be stored and dumped to the memory and displayed to ensure from the received message whether it is corrupted with errors or not. However, it is clearly noticed that the Coherent receiver is more efficient than the Non-coherent, but it still a bit expensive because used double look-up tables for cosine and sine in IQ converter. Finally, coherent receiver with Costas loop algorithm was implemented as well to improve the previous differential detection scheme. [ABSTRACT FROM AUTHOR]

The Radar Cross Section (RCS) plays a crucial role in radar systems, serving to detect and characterize radar targets. Moreover, the need to penetrate foliage and capture images of man-made structures like roads and buildings has driven the development of very high frequency/ultra high frequency (VHF/UHF)-based radar systems. In this context, we propose a novel polyphase-coded spread spectrum (PCSS) radar system designed for RCS measurements and ISAR imaging over VHF/UHF radio channels in open environments. To provide a comprehensive understanding, we examined the open range, considering factors such as amplitude distribution function, root mean square (RMS) delay, and coherence bandwidth, followed by a link budget analysis. We also conducted a comparative study of RCS measurements to evaluate the performance of the proposed radar system, demonstrating its effectiveness through theoretical calculations. Furthermore, we assessed the radar imaging capabilities by applying the CLEAN algorithm to improve the quality of the generated images. [ABSTRACT FROM AUTHOR]

This study chooses a transnational perspective to understand the practice of American culture in Indonesia. As this study discussed identity formed in social media and involved popular music singers, the theories applied in this study are the theories of identity, youth culture, new media, and popular music from the popular culture approach. In examining this study, the content analysis method was applied. After reviewing primary and secondary sources and find suppported theories for the data, it is find that the cegil identity is channeled through Taylor Swift and NIKI’s musicality due to the interconnection of youth culture and new media in treating popular music. The star and stardom of Swift and NIKI influence people's perspectives on their songs. The cegil community likes their lyricism in descriptive, imaginative, and poetic songs. Global access and media allow Spotify and X as the mediums to communicate and participate for cegil to express their feelings. They were also the place where the cegil term was coined. The last factor is a youth culture that treats music as the soundtrack of life and hence sees songs as a medium to express themselves. [ABSTRACT FROM AUTHOR]

The process by which debris flows shift from an active channel and branch out into new transport or depositional areas is termed "avulsion." They pose serious risks for structures and populations on debris-flow fans, yet avulsion mechanisms are relatively unknown and unaccounted for in hazard assessments, as compared to avulsions of rivers and streams, which are better understood. This study analyzes six debris-flow fans in the White Mountains of California and Nevada to identify relationships between avulsion locations and channel characteristics, constrain the controlling factors on avulsion, assess the probability that avulsion will occur at specified locations, and develop a method to predict avulsion locations. A database of avulsion locations and their channel characteristics was compiled in the field. These were compared to the characteristics of other positions on the fan surface that show evidence of debris flows that did not avulse through stepwise, binary logistic regression. Results indicate that two-thirds of avulsion likelihood can be attributed to the percentage of boulders at the site, slope angle, channel width, and the ratio between flow thickness and average slope at the avulsion location. The accuracy of this model can be improved when it accounts for the presence of a coarse channel plug, which increases the likelihood of avulsion. Application of the model is demonstrated by runout simulations with forced avulsions from modeled channel plugs. [ABSTRACT FROM AUTHOR]

A model of the channel and catchment components of sediment runoff has been developed. The model makes it possible to estimate the intensity of redistribution of river and bottom sediment in the riverbed, the size distribution of deposited or migrating particles, the mass of particles in the riverbed and catchment components of sediment load, as well as the contribution of the catchment component. The model is based on the assessment of the transport potential of the watercourse and the dynamics of the curves of the granulometric composition of bottom sediment, and products of soil and channel erosion. This approach is focused on the steady flow movement without additional sources of tributary sediment, intensive abrasion of river banks, and products of anthropogenic load. Calculations based on the model applied to the Narva River showed that the contribution of the catchment component to the sediment flow of this watercourse after intense rain is approximately 98%. The obtained results are well confirmed by the weak dynamics of channel deformations in the studied part of the watercourse. [ABSTRACT FROM AUTHOR]

Pellets have voids in their structure, which form a pore space. Pellet pores can be represented by closed volumes or channels, capillaries. The volume of capillaries can be estimated by impregnating pellets with water. The purpose of this work is to assess the possibility of studying the pore space of burnt pellets using the capillary-porous solids model. For this purpose, samples of laboratory and industrial pellets were presented. According to the data obtained, samples with a high moisture capacity value have a higher recoverability. This method of evaluating the pores of burnt pellets provides information about open porosity, which can be used to predict their recoverability. [ABSTRACT FROM AUTHOR]

The flow and heat transport presentation of the nanofluid flowing through the metal foam (MF) positioned inside the asymmetrical heated horizontal channel is evaluated computationally in the current study. The MF of 20 pores per inch (PPI) with porosity 0.918 is inserted into horizontal channel test section. The test segment is heated from the top wall with the help of plate (aluminum) heater assemblage positioned at the top of the channel. The novelty of the current examination is to extract the consequences of nanofluids such as Al2O3-H2O and CuO-H2O flowing through the MF filled test segment at various velocities ranging from 0.02 to 0.15 m/s. The conjugate heat transport examination is executed through MF region using integrated DEF (Darcy Extended Forchheimer) with LTE (local thermal equilibrium models). The improvement in thermal presentation achieved for nanofluids are likened with H2O and H2O-C2H6O2 (water with 50 % ethylene glycol) solution and also with clear channel. The procedure adopted in the current analysis is initially confirmed with the help of comparison of present work result with literature upshots. The outcomes are presented in terms of friction factor (FF), Nusselt number (Nu), Colburn j factor, performance evaluation criteria (PEC) and pumping power (PP). The CuO-H2O nanofluid showed the best performance (average PEC of 1.4) among all the fluids considered in the present examination.

In this paper, two heated blocks and three flexible baffles that are alternately placed on the upper and bottom sides of a rectangular channel are used to replicate the transient heat and air movement. The novelty of this research is the use of flexible baffles to destruct the thermal boundary layer with maintaining little pressure drop, and thus reducing the required pumping capacity. The finite thickness blocks are subject to a constant heat flux, while the baffles are very thin and deforms depending on the strength of the flow of coolant (air). Finite element method with arbitrary Lagrangian–Eulerian approach is used for solving such deforming domain problem. The problem is inspected transiently by varying the dimensionless time (τ=0.0 to 10) and two salient parameters which are Reynolds number Re=10−500, and baffle elasticity parameter E=105−108. Results show that the flexibility feature of the baffles contributes not only in directing the coolant towards the hot blocks, but also contributes in reducing the skin friction and pressure drop through the channel. At Re=150, the skin friction and pressure drop of the flexible baffles are 13.2% and 16.5%, respectively lesser than the rigid baffles. The improvement of Nusselt number with flexibility parameter is marginal and within a limited low Reynolds number, where the maximal improvement is about 3.4% at Re=150.

Abstrak Saluran Parit Berkat merupakan salah satu saluran di daerah rawa pasang surut Desa Punggur Besar, Kecamatan Sungai Kakap yang mengalami perubahan dasar saluran, yakni pendangkalan akibat proses sedimentasi. Pendangkalan yang terjadi di saluran Parit Berkat terutama pada bagian hilir dapat mengganggu aliran ke sungai dan menyebabkan meningkatnya muka air di hulu sehingga air lebih cepat meluap ke permukaan saat musim hujan atau saat terjadi air pasang dan dapat mengakibatkan kekeringan saat musim kemarau. Tujuan dari penelitian ini adalah untuk mengetahui debit angkutan sedimen dasar di saluran Parit Berkat. Data yang digunakan adalah data primer dan data sekunder. Data primer berupa penampang saluran dan sampel sedimen dasar. Data sekunder berupa peta catchment area, curah hujan harian stasiun Sungai Kakap PTK-12 dan tinggi muka air pasang surut selama 15 hari. Simulasi aliran dan angkutan sedimen menggunakan program aplikasi HEC-RAS 6.0 dengan metode Meyer-Peter Muller. Hasil penelitian menunjukkan besar angkutan sedimen dasar tertinggi saat kondisi pasang untuk debit periode ulang 10 tahun, yaitu sebesar 1,73 kg/det di titik 1, sedangkan saat kondisi surut, besar angkutan sedimen dasar terendah untuk debit periode ulang 10 tahun adalah sebesar 0,92 kg/det di titik 1. Kata kunci: sedimen dasar, HEC-RAS, Meyer-Peter Muller, saluran, Parit Berkat Abstract Parit Berkat channel is one of the channels in the tidal swamp area of Punggur Besar Village, Sungai Kakap District which has experienced changes in the basis of the channel, namely silting due to the sedimentation process. Siltation that occurs in the Parit Berkat channel, especially in downstream, can disrupt the flow to the river and cause an increase in the water level upstream so that water overflows to the surface faster during the rainy season or high tide and can cause drought during the dry season. This study aimed to determine the amount of bed load transport in the Parit Berkat channel. The data used are primary data and secondary data. Primary data are channel cross-sections and bed load samples. Secondary data are catchment area maps, daily rainfall of Sungai Kakap PTK-12 station, and tidal water levels for 15 days. Flow and sediment transport simulation using the HEC-RAS 6.0 application program with the Meyer-Peter Muller method. The results showed the highest bed load transport during tidal conditions for the 10-year return period, which was 1.73 kg/sec at point 1, while at low tide, the lowest bed load transport for the 10-year return period was 0.92 kg/sec at point 1. Keywords: bed load, HEC-RAS, Meyer-Peter Muller, channel, Parit Berkat

Purpose: hydraulic calculations of the current water supply network of the Chernozemelskaya irrigation system channels. Materials and methods. The materials for the calculations were: operational records of the Chernozemelskaya irrigation system, the results of field surveys of channels and data from instrumental measurements of water levels, velocities and water discharges in the surveyed discharge section lines of distributary channels. The field work was carried out according to the generally accepted rules and methods of surveys, hydrometric measurements and assessment of the reclamation facilities state. Channel hydraulic calculations were performed for the conditions of constant water flow in their channels on rectilinear sections. Calculations of the main elements of the water cross-section of the Chernozemelskaya irrigation system channels were carried out using passport data and the results of field surveys of these channels. Results. Calculations of the main elements of the water cross-section of the channels for the control stations on the Yashkul and Gashun distribution canals of the Chernozemelskaya irrigation system were performed, rating curves of discharge and average water flow velocity in channels from the depth of their filling were constructed; permissible (non-eroding and non-silting) velocities of water flow in the channels were determined. Conclusions. It was found for the discharge section line on the Gashun distribution canal, that siltation of the channel will occur at a water flow discharge of Q < 2.75 m³/s and channel filling of h < 1.0 m. When assessing the channel of the Gashun canal for the susceptibility to erosion, it was determined that the channel in the control station section can pass the specified discharge without being eroded. Checking the channel of the Yashkul distribution canal in the control section for siltation and erosion showed that its channel will not be eroded in the considered range of water flow velocities from 0.62–1.14 m/s.