Search

Purpose. The research purpose is to develop a mathematical model of a pressureless flow in a channel with the occurrence in some areas of overflow layer through the wall. Using this model, it is possible to calculate the overflow layer height and length, as well as the change in flow rate in the channel due to the withdrawal of part of the fluid as a result of the overflow. Methods. The research uses a comprehensive multi-stage analytical approach. Firstly, in order to develop a mathematical model for a pressureless flow in the channel with the occurrence in some areas of overflow layer through the wall, this research analytically determines the dependence of the flow rate through the channel wall based on formulas for calculating the weir discharge coefficient. At the second stage, a mathematical model of a hydraulic mixture pressureless flow in a rectangular channel with an overflow through the wall is developed to determine the parameters and flow regimes of the stream. Findings. The dependences of the dimensionless height of the overflow through the channel wall and the effective critical flow depth on the dimensionless current channel length have been obtained for various values of the acting force parameters and the process parameter of the fluid overflow through the channel wall. This made it possible to study the dynamics of changes in these values along the channel for various values of the specified parameters, and to assess the degree of influence of the relevant factors on the characteristics of the pressureless flow along the channel and the process of fluid overflow through wall. Originality. For the first time, the model of the pressureless flow in the channel is generalized for the case of occurrence in some areas of overflow layer through the wall, when the length and height of the overflow layer are not determined by a hole in the side surface, but are controlled by a decrease in the corresponding flow rate. For the first time, this model makes it possible to calculate the height and length of the overflow layer and the change in the flow rate in the channel due to the withdrawal of part of the fluid as a result of the overflow in cases of overflowing condition of the channel with the stream under unstable and non-calculated flow regimes. Practical implications. The mathematical model and the calculation results can be used to ensure the environmental safety of the logistics systems of mining enterprises, as well as to assess the volume of the environmental pollution in case of overflowing through the wall of the channels of pressureless hydraulic transportation of waste from mineral processing and metallurgical plants. [ABSTRACT FROM AUTHOR]

A new type of gold mineralization has been revealed in rocks of the basement of the Aldan-Stanovoi gold-bearing province, within the Spokoininsky ore cluster of the Tyrkandinsky gold-bearing region of southern Yakutia. A geological model has been created of an object with a bulk-minable nonlinear type gold mineralization related to elements of plicative structures and to the reverse fault type tectonics in the hosting metamorphic rocks of the basement. The modeled object is represented by a combination of lodes with veinlet-disseminated sulfide-(pyrite)-quartz mineralization. A complex has been refined of prospecting guides and criteria, that characterizes this mineralization type represented by the ore-bearing lodes with gold-quartz and gold-low-sulfide-quartz veinlet-disseminated mineralization in rocks of the basement and Late Jurassic-Early Cretaceous magmatic formations. The structural-geological position, the morphological type, the composition of the ore-hosting rocks and ores, and the principal parametric characteristics of the gold mineralization have been determined. Sampled intervals with the gold grades corresponding to the required parameters for the preliminary estimation have been distinguished in the exploration workings. Forecasted resources of the P2 category have been assessed.

Abstract Interpretation of deep‐water channel deposits is challenging because the spatial arrangement of their constituent lithologies is highly variable. This variability is often thought to be a signature of complex interactions between controlling boundary conditions and processes. A three‐dimensional forward stratigraphic model of a sinuous meandering channel is used to explore the production of channelised deep‐water stratigraphy. This model highlights three stages of stratigraphic evolution for channel belts: (1) an initial phase of rapid growth in mean belt width and variability in belt width driven by increasing channel sinuosity; (2) a subsequent phase of reduced belt‐width growth rate because of cutoff processes; and (3) a mature phase during which repeated bend lifecycles act to produce a statistically stable channel‐belt width. When a trajectory defining the vertical movement of a channel over time is added to the model, commonly recognised patterns of deep‐water channel‐belt stratigraphy are produced. These results demonstrate how forward stratigraphic models provide insights into processes governing the evolution of deep‐water stratigraphy that elude interpretations of static outcrops and seismic images of subsurface examples.

When studying medieval cities, along with the complex issues, including the structure, defense system, localization of cities according to written sources, identifying economic districts, is the study of the ancient irrigation system. Although the city of Syganak is mentioned in Arabic and Persian sources of the 10th century, we can find data on the irrigation system of the city in the work of the 16th century “Mikhman-name-iy” by Bukhara Fazlallah ibn Ruzbikhan. The waqf letters discovered by V.V. Bartold mention rivers near the city of Syganak and canals drawn from the Syrdarya. Data on the irrigation of Syganak are contained in the “Book of the Big Drawing”, “Drawing Book of Siberia” by S. Remezov. In Soviet times, E.I. Ageeva and G.I. Patsevich, V.N. Groshev drew attention to the issues of the irrigation system of Syganak. S. Zholdasbaev, who studied the city of Syganak for many years, paid special attention to the origin of the name of the canal Tuman aryk, derived from the Syr Darya. In this article, the authors drew attention to a controversial issue related to the location of the medieval city of Syganak. In some sources, the city is located on the right bank, in others – on the left bank of the Syrdarya River. Some researchers, relying on these sources, suggest that another city, Syganak, is mentioned in written sources. Our field studies have shown that the Syr Darya had several old channels in the vicinity of the city of Syganak. The discovery of these channels confirms that at one time the city was located on the left bank of the Syr Darya. The Sarysu and Shu rivers from Central Kazakhstan and Semirechye at the northwestern end of Karatau flowed into these old channels. Also, in the course of research along the ancient canals, several medieval cities and settlements of the cities of the Syr Darya were identified. The article provides information about ditches, derived from the Syr Darya, also provides data on the rivers originating in the southern part of Karatau, about their ancient names. The authors reveal that the toponymic names of Kyrash, Toktamys, Kelte-Shalkiya, Arystandy, Mynbulak found in vakuf charters have retained their names to this day.

Objective. The aim of the study was to determine the dependence of the distributions of average integral hydraulic resistances and convective heat transfer in turbulent flow in pipes with small (short channel) and large (long channel) sequences of semicircular periodic protrusions based on numerical solutions of the Reynolds equation systems, closed using Menter's shear stress transfer models, and energy equations on a multi-scale intersecting structured grid.Method. The calculation technique based on finite volume solutions of the Reynolds equation, closed using the Menter shear stress transfer model and the energy equation on a multi-scale intersecting structured grid, made it possible, with acceptable errors, to calculate the average coefficients of hydraulic resistance and heat transfer in a pipe with different quantities annular semicircular ledges.Result. Analytical comparisons were made of the calculated ratios for relative heat transfer and hydraulic resistance on the number of protrusions in channels with different values of relative heights of turbulators h/D, relative steps between turbulators t/D, different values of the Reynolds criteria Re, with other equivalent parameters, which showed that in in which case the qualitative deviations of the above characteristics are carried out monotonously, and in which case they are accompanied by extrema or inflections, and also showed cases of qualitative changes in the calculated characteristics. With the transition from 30 protrusions to 50, as a rule, only quantitative differences occur for the relative parameters of hydraulic resistance and heat transfer, and their qualitative changes are insignificant; with a further transition from 50 protrusions to 100, their quantitative changes also become insignificant.Conclusion. The nature of the patterns of distributions of the mean integral characteristics of flows and heat transfer for a channel with protrusions of various numbers must be taken into account for a short channel. An analysis of the calculated information obtained showed that when moving from a short channel with turbulators to a long one, most often, there is an increase in relative heat transfer and a decrease in relative hydraulic resistance, which justifies the advantage, from the point of view of intensification, of heat transfer by turbulence of the flow of the last channels in relation to the first channels.

• A new lamilloy structure equipped with staggered internal minichannels is put forward to achieve an effective cooling. • The lamilloy structure consists of three cooling effects: the impingement cooling, forced convective heat transfer and the film cooling. • The effect on the cooling performance of mass flow ratio and temperature ratio are investigated and compared. The efficiency improvement of the advanced high-power heavy-duty gas turbine will certainly make the design of the combustor develop in the direction of high temperature rise and high heat capacity. Lamilloy cooling is considered the promising cooling structure that can replace the currently commonly used film cooling. This paper proposes a novel long-channel lamilloy cooling structure equipped with internal channels and pin-fins used in combustor flame cylinders, and the cooling and flow characteristics of the proposed structure are studied by combining experiment and simulation. An experimental system is established to explore the cooling characteristic of the proposed structure, and the effect on the cooling characteristic of mass flux ratio (1.07 %∼2.35 %) and temperature ratio (0.5∼0.7) are studied and compared. The cooling effectiveness is found to be increased by 39.62 % when the mass flux ratio increases from 1.07 % to 2.35 % while keeping the temperature ratio at 0.5, and increased by 28.14 % when the temperature ratio increases from 0.5 to 0.7 while keeping the mass flux ratio at 1.07 %. The numerical results show that when T * =0.6, m f * increases from 1.07 % to 2.35 %, the η a increases from 0.469 to 0.628, correspondingly increased by 33.9 %. When m f * =1.93 %, T * increases from 0.5 to 0.7, the η a increases from 0.567 to 0.602, correspondingly increased by 6.27 %, the corresponding increment is weak. The flow field structure shows that strong vortex structures are formed around the pin-fins, and the secondary flow is induced when the coolant flows through the region of the pin-fins, which will enhance the local heat transfer effect. Moreover, the coolant ejecting from the film hole acts as a "baffle", blocking the direct contact between the mainstream and the LLC, playing a similar role to the film cooling. The long-channel lamilloy cooling structure proposed is an effective measure to replace the film cooling, and the research herein provides some reference for designing the combustor flame cylinder cooling structure. [ABSTRACT FROM AUTHOR]

• The improved two-phase flow model in channel is proposed. • The contact angle hysteresis is incorporated into the model. • The effect of channel wettability on liquid water distribution is investigated. • The effect of liquid water in channel on fuel cell is comprehensively investigated. • The existence of liquid water in straight channel reduced the optimal inlet humidity. Water management in channel plays a crucial role in influencing the performance of proton exchange membrane fuel cell (PEMFC). However, the limited comprehensiveness of existing model has hindered the investigation of this phenomenon. To investigate the impact of liquid water transport in channel on overall water and gas transport, as well as the performance of PEMFC, this study modifies the existing model by incorporating factors such as the channel wall wetting properties. Specifically, contact angle hysteresis is incorporated into the model. Based on the modified model, this study investigates the impact of liquid water in channel under various operational conditions and channel design schemes. The results demonstrate that the existence of liquid water in straight channel increases the liquid water saturation in gas diffusion layer while reducing the optimal inlet humidity and operating temperature. When relative humidity (RH) is around 0.5, the difference in the prediction results of the performannce of PEMFC is greatest when considering whether liquid water in channel is present or not. Channel wall with larger static contact angle and smaller hysteresis contact angle reduces liquid water volume fraction within channel, thereby enhancing oxygen transport while decreasing membrane water content. [ABSTRACT FROM AUTHOR]

Hydroelastic wave interaction with a circular crack of an ice-cover in a channel together with some related problems is considered, based on the linearized velocity potential theory and Kirchhoff plate theory. The domain decomposition method is adopted in the solution procedure. Two sub-domains are divided by the crack, one below the inner ice sheet and the other below the outer ice sheet. By using the Green function of an ice-covered channel, the velocity potential in the outer domain is established from the source distribution formula over an artificial vertical surface extended from the crack. The source distribution is expanded in both vertical and circumferential directions, which allows the velocity potential to be obtained in an explicit form with unknown coefficients. The velocity potential in the inner domain is expanded into a double series. An orthogonal inner product is used to impose continuity conditions on the artificial vertical surface and the edge conditions at the crack. The derived formulation is not just limited to the circular crack problem but can also be readily used in a variety of other problems, including wave diffraction by a surface-piercing vertical cylinder, polynya and circular disc floating on the free surface in a channel. Extensive results are provided for the forces on the inner ice sheet, the transmission and reflection coefficients. In particular, a detailed analysis is made on their behaviours near the natural frequencies of the channel, and the natural frequencies corresponding to the motion of the inner ice sheet. [ABSTRACT FROM AUTHOR]

Identification of geological features from seismic data such as faults, salt bodies, and channels, is essential for studies of the shallow Earth, natural disaster forecasting and evaluation, carbon capture and storage, hydrogen storage, geothermal energy development, and traditional resource exploration. However, manual seismic interpretation is distinctly subjective and labor-intensive. With the advent and rise of 3D surveys, the size of seismic data has increased dramatically, making purely manual interpretation impractical. Since 1989, a large number of machine learning-based methods for identifying geological features have been proposed to address these challenges. To date, these methods have not been reasonably synthesized. Motivated by a progressive increase in applications, this review presents an overview of advances in the utilization of machine learning to identify geological features from seismic data. First, we classify these methods from five different perspectives. Second, we provide a comprehensive overview of 241 publications related to seismic geological feature identification and offer a detailed analysis of the development of these methods categorized by geological feature type. Third, 20 field and 12 synthetic seismic datasets, which are publicly available and relevant to the identification of faults, salt bodies, channels, caves, and horizons, are cataloged. Fourth, we discuss the issue of false positive identification caused by the limited geological features in the training dataset. To address the problems of false positives and insufficient labeled training datasets, we propose a simulation framework for generating 3D synthetic seismic data and corresponding geological labels that include a rich variety of geological features. To the best of our knowledge, this is the synthetic seismic dataset that contains the richest geological features. Finally, we discuss in depth the current challenges and future opportunities to inspire further relevant research. • Conducted a comprehensive review of ML-based seismic subsurface feature identification from 1989 to 2023. • Synthesized publicly available datasets and open-source projects for fault, channel, salt body, cave, and horizon identification. • Released a large seismic dataset with fault labeling for benchmarking. • Discussed the impact of limited geological features in training data and proposed an improved workflow for generating 3D synthetic seismic data. • Provided an in-depth analysis of current challenges and future opportunities. [ABSTRACT FROM AUTHOR]

Research in the field of pharmacology aims to generate new treatments for pathologies. Nowadays, there are an increased number of chronic disorders that severely and durably handicap many patients. Among the most widespread pathologies, obesity, which is often associated with diabetes, is constantly increasing in incidence, and in parallel, neurodegenerative and mood disorders are increasingly affecting many people. For years, these pathologies have been so frequently observed in the population in a concomitant way that they are considered as comorbidities. In fact, common mechanisms are certainly at work in the etiology of these pathologies. The main purpose of this review is to show the value of anticipating the effect of baseline treatment of a condition on its comorbidity in order to obtain concomitant positive actions. One of the implications would be that by understanding and targeting shared molecular mechanisms underlying these conditions, it may be possible to tailor drugs that address both simultaneously. To this end, we firstly remind readers of the close link existing between depression and diabetes and secondly address the potential benefit of the pleiotropic actions of two major active molecules used to treat central and peripheral disorders, first a serotonin reuptake inhibitor (Prozac ®) and then GLP-1R agonists. In the second part, by discussing the therapeutic potential of new experimental antidepressant molecules, we will support the concept that a better understanding of the intracellular signaling pathways targeted by pharmacological agents could lead to future synergistic treatments targeting solely positive effects for comorbidities.

Protein tunnels are essential in transporting small molecules into the active sites of enzymes. Tunnels' geometrical and physico-chemical properties influence the transport process. The tunnels are attractive hot spots for protein engineering and drug development. However, studying the ligand binding and unbinding using experimental techniques is challenging, while in silico methods come with their limitations, especially in the case of resource-demanding virtual screening pipelines. Caver Web 1.2 is a new version of the web server combining the capabilities for the detection of protein tunnels with the calculation of the ligand trajectories. The new version of the Caver Web server was expanded with the ability to fetch novel ligands from the Integrated Database of Small Molecules and with the fully automated virtual screening pipeline allowing for the fast evaluation of the predefined set of over 4,300 currently approved drugs. The virtual screening pipeline is accompanied by a comprehensive user interface, making it a viable service for the broader spectrum of companies and the academic user community. The web server is freely available for academic use at https://loschmidt.chemi.muni.cz/caverweb.

Millimeter-wave (mmWave) communications promise Gigabit/s data rates thanks to the availability of large swaths of bandwidth between 10–100 GHz. Although cellular operators prefer the lower portions of the spectrum due to popular belief that propagation there is more favorable, the measurement campaigns to confirm this – conducted by ten organizations thus far – report conflicting results. Yet it is not clear whether the conflict can be attributed to the channel itself – measured in different environments and at different center frequencies – or to the differences in the organizations’ channel sounders and sounding techniques. In this paper, we propose a methodology to measure mmWave frequency dependence, using the 26.5–40 GHz band as an example. The methodology emphasizes calibration of the equipment so that the measurement results represent the channel alone (and not the channel coupled with the channel sounder). Our results confirm that free-space propagation is indeed frequency invariant – a well understood phenomena but to our knowledge reported nowhere else at mmWave to date. More interestingly, we found that specular paths – the strongest after the line-of-sight path and so pivotal to maintaining connectivity during blockage – are the least invariant compared to weaker diffracted and diffuse paths.

In this paper, the effect of water- iron oxide (Fe3O4) nanofluid on a channel heat transfer in the presence of perpendicular to the flow variable magnetic field with creating axial obstacles using a mixed single-phasee model is investigated numerically. The effects of magnetic field are added to governing equations of ferrofluid by writing codes and the problem geometry is generated and networked in Gambit 2.4 software. The network used is constructed in a three-dimensional and the governing non-linear differential equations are solved according to the finite volume method by using the Fluent software. Also, the effect of parameters such as obstacles in the flow path, dimensionless number of magnetic field intensity and Reynolds dimensionless number on heat transfer have been studied. The results show that creating obstacles in the flow path causes turbulence in the fluid flow, which increases the overall heat transfer. Also, the application of a magnetic field on the magnetic nanofluid causes the penetration of the cool boundary layer in the central parts of the channel and with increasing the intensity of the magnetic field, the penetration of this layer increases. As a result, the amount of Nusselt number and heat transfer has increased, and this improvement in heat transfer and Nusselt number increases with increasing Reynolds number.

Wireless systems have become an increasingly pivotal part of our lives. Various critical applications and use cases such as healthcare, financial transactions, e-commerce, transportation, industrial automation, etc. rely on secure and reliable communication for their proper operation. Despite their widespread adoption, conventional cryptographic security mechanisms are unable to scale with the increasingly decentralized and heterogeneous networks. Physical layer security (PLS), on the other hand, provides a promising complementary solution to ensure authenticity, confidentiality, integrity, and availability of legitimate transmissions by exploiting the dynamic characteristics of the wireless environment. Despite the plethora of literary works regarding different facets of PLS being present, a unified framework is still absent. In this paper, we provide a PLS framework that not only encompasses the existing works but also enables the development of next-generation PLS methods. In line with this, the importance of PLS for emerging technologies such as joint sensing and communication, vehicular communication, non-terrestrial networks, millimeter-wave, terahertz communication, etc. is highlighted. Furthermore, the key challenges and directions for future PLS mechanisms are identified.

This paper presents for the first time the design, fabrication, and demonstration of a dielectric waveguide (DWG)-based ortho-mode sub-THz interconnect channel for planar chip-to-chip communications. By combining the proposed new transition of microstrip line with DWG orthogonally, the ortho-mode transition is constructed to form an ortho-mode channel. The measured minimum insertion losses for the Ey11 mode and the Ex11 mode are 6.6 dB with 20.3-GHz 3-dB bandwidth and 6.5 dB with 55.2-GHz 3-dB bandwidth, respectively. The simulation and measurement results agree well with each other.

This paper conducts a state-of-the-art review for a particular emerging field of Production Research: pricing optimisation, channel and uncertainty. This is achieved by presenting a set of state-of-the-art papers accepted to this special issue, and co-word analysis to trace the development of this research field. Data for co-word analysis is based on literature search in the International Journal of Production Research, since 1961 using Web of Science with the Keywords 'pricing optimization', 'channel' or 'uncertainty'. Pricing approaches and tools have attracted more and more attentions from multiple disciplinary such as supply-chain management and marketing. The objective of this special issue is to contribute new insights to the extant body of knowledge in pricing optimisation, channel and uncertainty, specifically for 55th anniversary of International Journal of Production Research. [ABSTRACT FROM AUTHOR]

A novel approach for multichannel epilepsy seizure classification which will help to automatically locate seizure activity present in the focal brain region was proposed. This paper suggested an Internet of Things (IoT) framework based on a smart phone by utilizing a novel feature termed multiresolution critical spectral verge (MCSV), based on frequency-derived information for epileptic seizure classification which was optimized using a flower pollination algorithm (FPA). A wireless sensor technology (WSN) was utilized to record the electroencephalography (EEG) signal of epileptic patients. Next, the EEG signal was pre-processed utilizing a multiresolution-based adaptive filtering (MRAF) method. Then, the maximal frequency point at which the power spectral density (PSD) of each EEG segment was greater than the average spectral power of the corresponding frequency band was computed. This point was further optimized to extract a point termed as critical spectral verge (CSV) to extract the exact high frequency oscillations representing the actual seizure activity present in the EEG signal. Next, a support vector machine (SVM) classifier was used for channel-wise classification of the seizure and non-seizure regions using CSV as a feature. This process of classification using the CSV feature extracted from the MRAF output is referred to as the MCSV approach. As a final step, cloud-based services were employed to analyze the EEG information from the subject's smart phone. An exhaustive analysis was undertaken to assess the performance of the MCSV approach for two datasets. The presented approach showed an improved performance with a 93.83% average sensitivity, a 97.94% average specificity, a 97.38% average accuracy with the SVM classifier, and a 95.89% average detection rate as compared with other state-of-the-art studies such as deep learning. The methods presented in the literature were unable to precisely localize the origination of the seizure activity in the brain region and reported a low seizure detection rate. This work introduced an optimized CSV feature which was effectively used for multichannel seizure classification and localization of seizure origination. The proposed MCSV approach will help diagnose epileptic behavior from multichannel EEG signals which will be extremely useful for neuro-experts to analyze seizure details from different regions of the brain. [ABSTRACT FROM AUTHOR]

The pathogenesis of ventricular tachycardia (VT) in most patients with a prior myocardial scarring is reentry involving compartmentalized muscle fibers protected within the scar. Often the 12-lead ECG morphology of the VT itself is not available when treated with a defibrillator. Consequently, VT ablation takes on an interesting challenge of finding critical targets in sinus rhythm. High-density recordings are essential to evaluate a substrate based on whole electrogram voltage and activation delay, supplemented with substrate perturbation through alternate site pacing or introducing an extra stimulation. In this article, we discuss contemporary intracardiac electrogram targets for VT ablation, with explanation on each of their specific fundamental physiology. [ABSTRACT FROM AUTHOR]

Mass media serves as a veritable instrument for information dissemination in J-VJ_agriculture. This paperinvestigated farmers' access to mass media channels and their usage for receiving agricultural information. This study applied mixed research methods. The study involved a proportionate sample of 364 farm households selected using a systematic random sampling technique. A semi-structured interview schedule was administered during June and July of 2020. Descriptive statistics and bivariate analysis were employed for the data analysis. Three focus group discussions with model farmers were held, and the data was thematically analysed. The results indicated that mobile phones, radio, television, and print media were accessed by farmers to receive agricultural information. However, mass media methods have not been extensively used by farmers. The low ownership of media devices, lack of communication infrastructure, low coverage of agricultural programmes, and high levels of illiteracy were attributed to the low access and utilisation of mass media. This study therefore recommends that farmers be encouraged to own mass media outlets such as radio and mobile phones, and that the state extension system (government) and other development organisations work together to improve communication infrastructure such as power supply. The mass media channels should be promoted to increase the number of agricultural programmes they transmit per week and make them more suitable for local contexts. [ABSTRACT FROM AUTHOR]

Vibro-acoustic processes are an interacting set of pulsations of the working fluid and vibrations of mechanical structural elements. The simulation of vibro-acoustic processes in a long pipe with an elastic round cylinder is considered. The mathematical model is developed in a coupled formulation, when not only pressure pulsations cause pipe vibrations, but also vibrations of the mechanical subsystem affect sound wave propagation in the working fluid. The influence of vortex formation processes in the channel on the system dynamics is taken into account. The fluid flow is found using delayed detached eddy simulation. The flow regimes around a single round cylinder corresponding to various Reynolds numbers are investigated to validate the computational algorithm. The distributions of the flow quantities and vibro-acoustic behavior of the system are discussed. [ABSTRACT FROM AUTHOR]

The pipeline transportation of coal slurries is always subject to a temperature difference between the outdoors environment and the fluid body. As slurries' viscosity is typically temperature dependent, the flow is accompanied by the heat transfer. In this study, we used the CFD method to investigate temperature distributions and flow structures in straight and curved channels, which has not previously been investigated, according to our knowledge. First, the results demonstrate that the cooling process influences the flow structures along the stream. The fluid turns more sharply in the cooler fluid in the curved channel, the streamlines overlap at an earlier position within the bend, and the velocity maximum zone is wider. Cooling also has a significant impact on transverse flow. Because of the higher viscosity of the more cooled fluid and thus the difficulty of shearing the fluid in the stream-wise direction, the vorticity and strength of the vortex flow are greater. The fluid velocity at the central part of the channel points toward the inner wall at the beginning of the bend, resulting in an inner-wall biased temperature distribution, as the heat transfer is partially carried out by the fluid velocity. The central velocity points toward the outer wall at the end of the bend, resulting in the outer-wall biased temperature profile. [ABSTRACT FROM AUTHOR]

The graphene-based nano-mechanical systems have attracted a lot of attention due to their unique properties. Owing to its planar shape, it is hard to control the direction of motion of graphene. In this study, a directional system based on graphene with a channel driven by a thermal gradient was examined by means of molecular dynamics simulations. The results showed that the channel could direct the motion and correct the rotation of graphene nanoflakes. The movement of graphene nanoflake not only depended on the interaction between the nanoflake and the substrate, but also the configuration of the graphene in the channel. A larger thermal gradient was needed to drive a hydrogen-passivated graphene nanoflake. However, the movement of a passivated nanoflake was more stable. Our results showed that a passivated graphene nanoflake could move steadily along a direction in a channel, which might shed light on the design of nano-mechanical systems based on graphene. [ABSTRACT FROM AUTHOR]

The experimental examination of local heat transfer, thermal intensification, friction factors, and thermal performance factors (TPF) in a rectangular channel with square-winged transverse baffles (SW-TB) are presented in this paper. The purpose of this study is to modify the typical transverse baffles (TB) into square-winged transverse baffles (SW-TB) in order to improve the thermal performance and heat transfer rate of the channel. The effects of SW-TBs with various wing attack angles and Reynolds numbers on the heat transfer performance characteristics were examined using a thermochromic liquid crystal sheet. In the experiments, the SW-TBs were attached to the bottom wall of the channel, which had an aspect ratio (W:H) of 3.75:1. The SW-TBs had a width (w) of 150 mm, a square perforated cross-sectional area (a × b) of 8 × 8 mm2, and attack angles (θ) of 0° (solid transverse-baffle), 22.5°, 45°, 67.5°, and 90°. The bottom wall of the channel was evenly heated, while the other walls were insulated. The temperature contours on the heated surface were plotted using temperatures obtained through using the thermochromic liquid crystal (TLC) image-processing method. Experimental results revealed that the SW-TBs created multiple impinging jets, apart from the recirculation. At the proper attack angles (θ = 22.5° and 45°), the SW-TBs offered greater heat transfer rates and caused lower friction losses, resulting in higher TPFs than the solid transverse baffles. In the current work, channels where the SW-TBs display a θ = 45° presented the greatest TPF, as high as 1.26. The multiple impinging jets issuing by the SW-TBs suppressed the size of the recirculation flow and allowed better contact between the fluid flow and channel wall. [ABSTRACT FROM AUTHOR]

For the high performance of a fuel cell where a bipolar plate (BP) is applied, rectangular channel, microchannel width, micro-rib, enough channel quantity, adequate channel depth, and innovative flow field design should be realized from a configuration standpoint. In this study, a stainless-steel BP with a microchannel flow field is fabricated with a powder bed fusion (PBF) 3D printer to improve fuel cell performance. A BP with a triple serpentine flow field, rectangular channel, 300 μm channel width, 300 μm rib, and 500 μm channel depth is designed. The print is completed perfectly until the flow field. The bending phenomenon due to thermal deformation does not occur in the BP fabricated by designing the thickness at 2 mm. Performance tests are conducted using fabricated stainless-steel BPs. The current density value is 1.2052 A/cm2 at 0.6 V. This value is higher by 52.8% than the BP with 940 μm channels (rectangle, 940 μm ribs, and 500 μm channel depth). In addition, the value is higher by 24.9% than a graphite BP with 940 μm channels (rectangle, 940 μm ribs, and 1000 μm channel depth). The current density values are measured at 0.6 V for 260 h. [ABSTRACT FROM AUTHOR]

The low terahertz band (0.1–1 THz) offers very high data rates for novel mobile applications and constitutes a promising candidate to meet the requirements in aviation, enabling future wireless in-flight entertainment (IFE) systems. An extensive knowledge of the propagation effects in the radio channel in complex scenarios is a prerequisite to successfully design a communication system. This article presents a measurement campaign in a real aircraft investigating the radio channel at 300 GHz for different deployments of a wireless IFE system. The propagation effects as well as temporal and spatial channel characteristics are analyzed for likely communication links between an access point and a user equipment (UE). In the same way, interference links between two UEs are studied, reporting transmission and reflection losses for various components of the aircraft. A deterministic and geometry-based channel model is derived and extended to cover the effect of human blockage that suggests an integration of the access point into the passenger service unit. The measurement and realistic path loss models can be used in further link and system level simulations and contribute to the design of future IFE systems. [ABSTRACT FROM AUTHOR]

Avian obligate brood parasites and their hosts exhibit coevolution, where parasites respond to the evolution of host defences with counter-adaptations, such as egg mimicry, which can then lead to the evolution of more efficient host defences. Using objective measurements and avian visual modelling, we quantified the degree of similarity between the eggs of the channel-billed cuckoo (Scythrops novaehollandiae) and the eggs of three host species from the hosts' visual perspective. We found no evidence that this cuckoo species has host-specific egg types, but it does appear to mimic one of its primary hosts, the pied currawong (Strepera graculina), in both colour and pattern. Currawongs showed significantly higher interclutch variation in colour and luminance than the other two hosts and had significantly lower intraclutch variation in pattern than interclutch variation. High interclutch and low intraclutch variation in a host could make it more difficult for a cuckoo to match closely any particular host clutch, potentially allowing a host to detect a parasitic egg more easily. This is the first empirical study using objective measurements to quantify the degree of egg mimicry in the channel-billed cuckoo and the results suggest a potential host defence to egg mimicry that merits further investigation. [ABSTRACT FROM AUTHOR]

A three‐dimensional numerical laminar mixed convection analysis has been examined to investigate thermal transfer, fluid flow, and second law behaviors in an inclined channel with four heated blocks within, submitted under a constant heat flux using Al2O3–Cu water‐based hybrid nanofluid as a circulating fluid. Our main purpose is to perform a close‐to‐reality approach, which leads to results that can be applied in many experimental and industrial fields. This study focuses on the analysis of the effect of Reynolds number (100 ≤ Re ≤ 500), Richardson number (0.1 ≤ Ri​​​​​​​ ≤ 2), nanoparticles concentration (0 ≤ ϕ $\phi $ ≤ 0.05), blocks positions, and inclination of the channel (0° ≤ θ ≤ 90°) to examine the variation of Nusselt number Nu, temperature gradient entropy Sh, fluid friction entropy Sf, and the number of Bejan Be. Results show that the enhancements provided to the Nu number by elevating previous parameters reached a percentage rate of 3.2% when increasing ϕ $\phi $, 12.9% with Ri, and 8.58% with Re; however, the aligned position reveals higher values. There is also an increment in Be number when Ri and Re increase, but in this case, the not‐aligned position reveals the highest values. To predict Nu number values, correlations were developed to examine the effects of ϕ $\phi $, Ri, and Re on Nu, for both aligned and not‐aligned positions. [ABSTRACT FROM AUTHOR]

States and channels are fundamental and instrumental ingredients of quantum mechanics. Their interplay not only encodes information about states but also reflects uncertainties of channels. In order to quantify intrinsic uncertainties generated by channels, we exploit the action of a channel on an orthonormal basis in the space of observables from three different perspectives. The first concerns the uncertainty generated by a channel via noncommutativity between the Kraus operators of the channel and an orthonormal basis of observables, which can be interpreted as a kind of quantifier of the total uncertainty generated by a channel. The second concerns the uncertainty in terms of the Tsallis- entropy of the Jamiołkowski–Choi state associated with the channel via the channel–state duality, which can be interpreted as a quantifier of the classical uncertainty generated by a channel. The third concerns the uncertainty of a channel as the deviation from the identity channel in terms of the Hilbert–Schmidt distance, which can be interpreted as a kind of quantifier of the quantum uncertainty generated by a channel. We reveal basic properties of these quantifiers of uncertainties and establish a relation between them. We identify channels producing the minimal/maximal uncertainties for these three quantifiers. Finally, we explicitly evaluate these uncertainty quantifiers for various important channels, use them to gain insights into the channels from an information-theoretic perspective, and comparatively study the quantifiers. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To investigate the correlation between scoliosis direction and oblique lateral lumbar interbody fusion (OLIF) operation channel angle in patients with degenerative lumbar scoliosis. PATIENTS AND METHODS: 80 cases of degenerative lumbar scoliosis and 40 cases of lumbar degenerative diseases without scoliosis were retrospectively studied in our hospital from January 2018 to January 2021. The general data and imaging indexes of all patients were analyzed, and the correlation between the rotation angle of vertebral body and the channel angle of OLIF operation was evaluated. RESULTS: The distance between abdominal aorta and psoas muscle in L2-3 and L3-4 segments, and the distance between abdominal aorta and lumbar sympathetic trunk in L3-4 segments, as well as the angles of OLIF operation channels in L2-3, L3-4 and L4-5 segments of the right-scoliosis group were all significantly greater than those in the no-scoliosis group (p < 0.05). The distance between abdominal aorta and lumbar sympathetic trunk in L4-5 segments of the left-scoliosis group was significantly greater than that in the no-scoliosis group and the right-scoliosis group (p < 0.05). The angle of OLIF operation channel in L3-4 and L4-5 segments of the left-scoliosis group was significantly smaller than that in the non-scoliosis group (p < 0.05), and the distance between psoas major and transverse axis of vertebral body in L2-3 and L3-4 segments of the left-scoliosis group was significantly greater than that in the non-scoliosis group (p < 0.05). The distance between adjacent vertebral bodies in L2-3 and L3-4 segments of the right-scoliosis group was significantly larger than that in the non-scoliosis group (p < 0.05). The distance between psoas major and transverse axis of vertebral body in L4-5 segment of the left-scoliosis group was significantly larger than that in the no-scoliosis group and the right-scoliosis group (p < 0.05). Correlation analysis showed that there was a negative correlation between OLIF operation channel angle and vertebral rotation angle in the left scoliosis group (p < 0.05), and a positive correlation between OLIF operation channel angle and vertebral rotation angle in the right scoliosis group (p < 0.05). CONCLUSIONS: The scoliosis direction of patients with degenerative lumbar scoliosis can directly affect the angle of OLIF operation channel, so targeted design and operation adjustment should be given according to the scoliosis direction of patients before operation. [ABSTRACT FROM AUTHOR]

Dynamic channel pruning has been proved to be an effective method by dynamically adjusting the inference path to reduce the computing costs. However, in most existing work, the classification performance decreases rapidly with the increase of pruning rate because their pruning strategy weakens the representation ability of the model to a certain extent. To resolve this problem, a dynamic channel pruning method based on activation gate (DCPAG) is proposed, which can better maintain the classification performance while reducing the computing costs. First, a pipeline aiming for generating pruning strategy, namely channel pruning auxiliary (CPA) is proposed, which considers both the representation ability and computing costs. Second, the pruning strategy generated by CPA is embedded into dynamic rectifying linear unit (DyReLU) to form the embedded dynamic rectifying linear unit (EB-DyReLU), which achieves dynamic channel pruning while maintaining the representation capability. Third, each input sample was self-classified according to its identification difficulty during pruning, and additional training was given to hard samples to achieve better classification performance. Finally, some experiments are carried out on CIFAR-10 and ImageNet respectively to verify the effectiveness of DCPAG in accuracy and floating point of per second (FLOPs). The results show that the proposed method achieves better performance than other similar channel-based methods at the same pruning rate. Specifically, this method not only achieves 0.5-1.5% improvement in classification accuracy, but also reduces the computational costs by 5%-20%. [ABSTRACT FROM AUTHOR]

We investigated the effect of the acetylcholine muscarinic receptor inhibitor benztropine on voltage-dependent K+ (Kv) channels in rabbit coronary arterial smooth muscle cells. Benztropine inhibited Kv currents in a concentration-dependent manner, with an apparent IC50 value of 6.11 ± 0.80 μM and Hill coefficient of 0.62 ± 0.03. Benztropine shifted the steady-state activation curves toward a more positive potential, and the steady-state inactivation curves toward a more negative potential, suggesting that benztropine inhibited Kv channels by affecting the channel voltage sensor. Train pulse (1 or 2 Hz)-induced Kv currents were effectively reduced by the benztropine treatment. Furthermore, recovery time constants of Kv current inactivation increased significantly in response to benztropine. These results suggest that benztropine inhibited vascular Kv channels in a use (state)-dependent manner. The inhibitory effect of benztropine was canceled by pretreatment with the Kv 1.5 inhibitor, but there was no obvious change after pretreatment with Kv 2.1 or Kv7 inhibitors. In conclusion, benztropine inhibited the Kv current in a concentration- and use (state)-dependent manner. Inhibition of the Kv channels by benztropine primarily involved the Kv1.5 subtype. Restrictions are required when using benztropine to patients with vascular disease. [ABSTRACT FROM AUTHOR]

Modeling the vortex intensification of turbulent heat transfer in narrow engine ducts using single-row dimples was carried out within the framework of multi-block computing technologies implemented in a special VP2/3 package. The cases of a rectangular section with the placement of vortex generators—single-row packages of oval and spherical dimples on the initial hydrodynamic section and the section of the stabilized flow are excluded. The connection between the generated vortex structures and the predominant increase in heat transfer compared to the increase in hydraulic losses for various dimple layouts has been established: zigzag, ladder, and centers shifted and in a longitudinal-transverse order. The superiority in heat removal from the thickness with inclined oval dimples is shown—1.23 times compared to spherical ones with a decay in hydraulic resistance by 1.16 times. [ABSTRACT FROM AUTHOR]

The motion of an individual particle in a circular channel flow induced with fluid injection is considered. Analysis takes into account drag and gravitational forces acting on an individual particle. The change in the radial structure of the flow in a channel with fluid injection on the motion of a particle is studied. A number of simplifying assumptions about the structure of the fluidflow in the channel makes it possible to obtain an analytical solution of the problem for particles. The results of a qualitative analysis of particle trajectories in the channel with fluid injection are compared with numerical simulations. The singular points of the particle trajectory are found in a wide range of characteristic non-dimensional parameters of the problem. The modes of motion of an individual particle in a channel with fluid injection are classified depending on the Stokes and Froude numbers. [ABSTRACT FROM AUTHOR]

The present study intended to review the historical development of the regime geometry equations proposed by many researchers since 1895. Kennedy started the search for the attributes of stable channels on the Upper Bari Doab Canal of Punjab in 1980-1984. The regime concept was presented by Lindley (1919) that later on Lacey (1930) modified to a set of most widely used regime relations. Later on, Blench (1941-1957), and Simons and Albertson (1960) presented their equations. This period is called 'canal regime period' because most of the research focused on canal design. The concept of regime was extended to river systems by Leopold and Maddock in 1953. In 1963, Henderson proposed some regime equations that can be applied for predicting canal and river geometry. This period was the transition from canal regime period to river regime period and from an empirical approach to analytical approach and is called as 'Transitional Period'. Many other researchers written the information based on analytical approach, or a combination between analytical and empirical approaches, and more focused to river regime especially gravel bed river regime. This period is, called 'River regime period'. Flow discharge, sediment size, and bed-load sediment are the three main factors that influence the geometry of alluvial channels. The hydraulic geometry relationships indicate that sediment size and bed-load sediment strongly influence the channel slope, moderately influence the flow velocity, and slightly influence the channel depth and the channel width. This study also shows that in terms of Shields parameter, the exponents of discharge, sediment size, and sediment transport are dependent on the relative submergence (D/d50). [ABSTRACT FROM AUTHOR]

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.

The 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 (K m  = 33 mM) for K than wild-type Kir1.1b (K m  = 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.

Crucial physiological processes, like neural communication and muscle contraction, are mediated by protein channels in cell membranes. These natural channels typically have a central hydrophilic pore with tightly defined dimensions, which can be opened or closed ('gated') by external stimuli. Mimicking natural ion channels using synthetic molecules is a long-standing goal in artificial channel research. Although current synthetic channels have not yet achieved the same combination of high activity, high selectivity, and gating as natural channels, foldamers offer a new approach. Foldamers are unnatural oligomers that fold into defined three-dimensional shapes, similar to the way that natural polypeptides fold into secondary structures. With defined shapes and often multi-nanometre dimensions, foldamers have become valuable tools to mimic the behaviour of natural proteins in membranes. This review highlights selected recent examples of foldamer channels, examples that indicate how foldamer architectures may lead to controllable channels with high activity and selectivity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Oxygen delivery and tear exchange are considered essential to maintain corneal homoeostasis during contact lens wear. Since the 1940s, fenestrations and back surface channels have been utilised in scleral, corneal rigid, and soft contact lenses in an attempt to enhance corneal oxygen transmission, facilitate the removal of carbon dioxide from the post-lens tear layer, minimise corneal oedema and prevent post-lens tear stagnation. This review examines the use of contact lens fenestrations and channels in both clinical and laboratory settings, and the effect of these modifications upon tear exchange and corneal oedema. Despite almost a century of modifying contact lenses to alter tear dynamics and promote corneal health, the evidence regarding the efficacy of fenestrations and channels is mixed.

Channels are typically gated by several factors, including voltage, ligand and mechanical force. Most members of the calcium homeostasis modulator (CALHM) protein family, large-pore ATP release channels, exist in different oligomeric states. Dynamic conversions between CALHM1 heptamers and octamers to gate the channel were proposed. Meanwhile, the latest study observed that the transient receptor potential vanilloid 3 (TRPV3) channel adopts a dynamic transition between pentamers and canonical tetramers in response to small molecule treatment. These results suggest that oligomeric rearrangement may add a new layer to regulate the channel activities., Competing Interests: Yue Ren, Xue Yang and Yuequan Shen declare that they have no conflict of interest., (© The Author(s) 2024.)

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., (© 2024 The Authors. The Journal of Physiology © 2024 The Physiological Society.)