5,783 results on '"Channel"'
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152. Determination of Hydraulic Roughness Coefficients of Some Vegetated Species in Awka, Nigeria
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Luis Chukwuemeka Orakwe, Kingsley Nnaemeka Ogbu, Joseph Ikenna Ubah, Chike Pius Nwachukwu, Chinaza Rosemary Akamonye, and Uchenna Peter Okoro
- Subjects
hydraulic roughness coefficient (n) ,erosion ,discharge ,channel ,vegetation ,Mathematics ,QA1-939 ,Physics ,QC1-999 ,Medicine (General) ,R5-920 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Agriculture (General) ,S1-972 - Abstract
In this study, selected types of grasses were studied to determine their hydraulic roughness coefficient and to select the most suitable grass for erosion control. The experiments were performed in twelve trapezoidal open channels measuring 5 m x 0.12 m x 0.03 m at different flow depths (0.001m, 0.002m, 0.003m, 0.004m and 0.005m) and at varying bed slope (0.2%, 0.3%, and 0.4%). Overall, Bahama grass showed the highest Manning’s n-value due to its deep root system and creeping nature. For each slope, the degree of submergence, Reynolds number, and flow depth increases as Manning’s n decreases. As the flow depth increases, the Reynolds number increased while the drag coefficient, Cd decreases.
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- 2022
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153. The difference between drainage channels and sewers in rural areas: from sewage quality to bacterial characteristics
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Yun Han, Wenkai Li, Tianlong Zheng, Guanghuan Ge, Ke Feng, Po Gao, and Wenhu Cheng
- Subjects
bacteria ,channel ,collection system ,rural sewage ,sewer ,Environmental technology. Sanitary engineering ,TD1-1066 - Abstract
Channels and sewers are commonly used to collect sewage during extensively rural areas. The sewage and bacterial characteristics of rural sewage collection systems can influence their operation and maintenance performance which further affect appropriate system decision. In this study, eight rural sewage collection systems (four each of channels and sewers) were applied to evaluate the sewage quality, bacterial characteristics, and their differences of two kinds of collection systems. The results indicate that significantly distinction existed between the rural sewage collection systems of channels and sewers. Sewage in channels had higher suspended solid (SS) concentration but lower sulfide concentration than that in sewers. The SS, sulfate, and chemical oxygen demand (COD) removal capacity in channels was nearly 3.5, 4.0, and 0.6 times than those in sewers. At least 14 genera and 18 species of bacteria showed significantly distinction between channels and sewers even their main phylum, genus, and species of bacteria communities was Proteobacteria (∼70.3%), Acinetobacter (∼22.3%), and Pseudomonas fragi (∼13.8%), respectively. The structural characteristics and bacterial function caused the difference between channels and sewers. Overall, this study revealed the intrinsic and essential differences of channels and sewers, providing basic and meaningful data for rural sewage collection systems decision. HIGHLIGHTS Sewage quality and bacterial characteristics of channels and sewers were significantly different.; Channels had better SS and sulfate removal abilities but lower COD removal abilities.; Fourteen genera and 18 species of bacteria showed significant distinction between channels and sewers.; Structural characteristics and bacterial function caused the difference between channels and sewers.;
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- 2022
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154. Sediment controls on the transition from debris flow to fluvial channels in steep mountain ranges.
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Neely, Alexander B. and DiBiase, Roman A.
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DEBRIS avalanches ,SEDIMENT control ,CHANNEL flow ,MASS-wasting (Geology) ,FLUVIAL geomorphology ,EROSION ,RATE setting - Abstract
Steep channel networks commonly show a transition from constant‐gradient colluvial channels associated with debris flow activity to concave‐up fluvial channels downstream. The trade‐off between debris flow and fluvial erosion in steep channels remains unclear, which obscures connections among topography, tectonics, and climate in steep landscapes. Here, we analyze steep debris‐flow‐prone channels across the western United States and observe: (1) similar maximum channel gradients across a range of catchment erosion rates and geologic settings; and (2) lengthening colluvial channels with coarsening sediment cover. Following this compilation, we hypothesize that steep channel gradients are controlled by two competing thresholds of motion for bed‐sediment cover: bed failure by mass‐wasting and fluvial entrainment. We use downstream patterns in discharge, channel geometry, and sediment size to calculate discharges needed to mobilize sediment cover by both mechanisms across channels in the San Gabriel Mountains (SGM) and northern San Jacinto Mountains (NSJM) in southern California. Across steep colluvial channels in both landscapes, decadal discharges are below fluvial entrainment thresholds but above mass‐wasting entrainment thresholds for D50 (median) sediment sizes, consistent with recent debris flows captured by repeat imagery. Colluvial channel gradient is similar despite > 3× contrasts in surface sediment grain size. In concave‐up fluvial channels downstream, decadal discharges exceed fluvial entrainment thresholds, and mass‐wasting is not predicted on lower gradients. In both landscapes, fluvial channels steepen downstream compared to gradients needed to mobilize sediment cover, which we interpret to reflect downstream increases in sediment flux. Coarser sediment supply in the NSJM than the SGM increases fluvial entrainment thresholds, which increases total channel relief in the NSJM by (1) lengthening colluvial channels shaped by debris flows and (2) increasing fluvial channel gradients. Our compilation and downstream analysis show how differing sensitivity of fluvial and debris flow processes to sediment grain size impacts the relative relief of colluvial and fluvial regimes in headwater channel networks. [ABSTRACT FROM AUTHOR]
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- 2023
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155. Improving mobile communications with antennas that map the channel and move to local maxima.
- Author
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Artner, Gerald
- Subjects
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MOBILE antennas , *MONOPOLE antennas , *ANTENNAS (Electronics) , *WIRELESS communications , *OFFICE environment , *WIRELESS channels - Abstract
A technique is proposed that improves wireless communication channels in fading environments. The device creates a map of channel measurements. The device then moves its antenna to positions of the previously measured maximum within its reach. Proof‐of‐concept measurements were performed for smartphone‐sized devices in an office environment. A quarter‐wavelength monopole antenna for the 2.4 GHz frequency band successfully kept the channel at local maxima. The results show that small antenna movements over half of a wavelength are sufficient to keep the channel in local maxima, to avoid deep fading notches, and to improve channels over state‐of‐the‐art antennas that move with their devices. A channel model for the wireless communication channel of mobile devices with channel maximum antennas is proposed based on the measurement results. [ABSTRACT FROM AUTHOR]
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- 2023
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156. The alleviation of ammonium toxicity in plants.
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Xiao, Chengbin, Fang, Yuan, Wang, Suomin, and He, Kai
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AMMONIUM , *CROP yields , *CROP quality , *POISONOUS plants , *AGRICULTURE - Abstract
Nitrogen (N) is an essential macronutrient for plants and profoundly affects crop yields and qualities. Ammonium (NH4+) and nitrate (NO3−) are major inorganic N forms absorbed by plants from the surrounding environments. Intriguingly, NH4+ is usually toxic to plants when it serves as the sole or dominant N source. It is thus important for plants to coordinate the utilization of NH4+ and the alleviation of NH4+ toxicity. To fully decipher the molecular mechanisms underlying how plants minimize NH4+ toxicity may broadly benefit agricultural practice. In the current minireview, we attempt to discuss recent discoveries in the strategies for mitigating NH4+ toxicity in plants, which may provide potential solutions for improving the nitrogen use efficiency (NUE) and stress adaptions in crops. [ABSTRACT FROM AUTHOR]
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- 2023
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157. Model test based study on icing process of long-distance water channel operating at low temperature environment.
- Author
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Wang, Yuguo, Ren, Wenyuan, Liu, Hongtai, Jin, Ruishan, Liang, Zhichao, Niu, Lisi, and Zhang, Aijun
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LOW temperatures , *WATER efficiency , *WATER temperature , *ICE , *FLUMES - Abstract
The icing problem seriously affects the efficiency of channel water delivery in low temperature conditions. A low-temperature and long-distance channel model test platform was established to study the icing process. Through this model test platform, water temperature and formation of ice cover were tested and discussed. Furthermore, the relationship between border ice width and its influencing factors were studied quantitatively. The test results show that through the recirculating flume at a negative temperature environment, the model test platform can simulate the icing process under a long-distance water delivery situation. The water temperature decreases with the increase of delivery distance and operating time. The formation of ice cover begins from the growth of border ice; however, the static formation of ice cover is rapid, but the dynamic formation of ice cover shows an obvious process of border ice lateral growth. An equation for border ice width and ice concentration was established for prediction. [ABSTRACT FROM AUTHOR]
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- 2023
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158. Role of voltage-gated proton channel (Hv1) in cancer biology.
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Alvear-Arias, Juan J., Pena-Pichicoi, Antonio, Carrillo, Christian, Fernandez, Miguel, Gonzalez, Tania, Garate, Jose A., and Gonzalez, Carlos
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PROTONS ,REPRODUCTION ,BIOLOGY ,CYTOPLASM ,SPERMATOZOA ,ION channels ,TUMOR microenvironment ,BIOLUMINESCENCE ,CARCINOGENESIS - Abstract
The acid-base characteristics of tumor cells and the other elements that compose the tumor microenvironment have been topics of scientific interest in oncological research. There is much evidence confirming that pH conditions are maintained by changes in the patterns of expression of certain proton transporters. In the past decade, the voltage-gated proton channel (Hv1) has been added to this list and is increasingly being recognized as a target with onco-therapeutic potential. The Hv1 channel is key to proton extrusion for maintaining a balanced cytosolic pH. This protein-channel is expressed in a myriad of tissues and cell lineages whose functions vary from producing bioluminescence in dinoflagellates to alkalizing spermatozoa cytoplasm for reproduction, and regulating the respiratory burst for immune system response. It is no wonder that in acidic environments such as the tumor microenvironment, an exacerbated expression and function of this channel has been reported. Indeed, multiple studies have revealed a strong relationship between pH balance, cancer development, and the overexpression of the Hv1 channel, being proposed as a marker for malignancy in cancer. In this review, we present data that supports the idea that the Hv1 channel plays a significant role in cancer by maintaining pH conditions that favor the development of malignancy features in solid tumor models. With the antecedents presented in this bibliographic report, we want to strengthen the idea that the Hv1 proton channel is an excellent therapeutic strategy to counter the development of solid tumors. [ABSTRACT FROM AUTHOR]
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- 2023
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159. Heat transfer mechanism and thermal performance of a channel with square-wing perforated transverse baffles installed: effect of square-wing location.
- Author
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Eiamsa-Ard, Smith, Phila, Arnut, Pimsarn, Monsak, Maruyama, Naoki, and Hirota, Masafumi
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HEAT transfer , *NUSSELT number , *JETS (Fluid dynamics) , *PRESSURE drop (Fluid dynamics) , *REYNOLDS number - Abstract
The aim of this study is to report the influence of wing position (h/e) of perforated transverse baffles with square-wings (SW-PBs) on heat transfer rate and pressure drop characteristics in a channel. The channel has a cross-sectional dimension of 15 cm × 4 cm and a length of 60 cm. Two types of baffles: Solid transverse baffles and square-wing perforated transverse baffles, are comparatively tested. The baffle pitch ratio (p/e) is set to 5.0 and remains constant throughout all experiments which encompass Reynolds numbers (Re) of 6000, 9000, 12,000, 15,000, 18,000, 21,000, and 24,000. Square-wings are introduced at four different locations, h/e = 0.92 (highest wing location), 0.83, 0.75, and 0.67 (lowest wing location). The maximum heat transfer rates achieved in channels with SW-PBs at h/e = 0.92, 0.83, 0.75, and 0.67 are 148%, 157%, 166%, and 180% above that of a plain channel, while pressure losses increase by 9.51–10.69, 9.56–10.79, 9.59–10.86, and 9.64–10.99 times, respectively. Experimental results show that square-wings create multiple impinging jet flows and Nusselt number peaks appear adjacent to the rear of the perforated transverse baffles. When compared to solid transverse baffles, SW-PBs cause lower pressure losses and yield higher thermal performance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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160. Analysis of factors determining numerical solution in the calculation of flow with combustion using the ONERA experimental model.
- Author
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Liu, W.
- Abstract
Three-dimensional numerical simulation of a transverse hydrogen jet blowing into a duct with a supersonic flow of air (warmed by a fire heater) has been carried out. The study is based on experimental data obtained at the ONERA-LAERTE facility. The RANS equations for the reacting gas were solved, closed by the SST model and various kinetic mechanisms of hydrogen combustion in air. The channel wall roughness was taken into account in this model. The dependence of the flow characteristics on such physical factors as the shape of the fuel injector channel, the effective roughness height, and various methods of describing molecular diffusion has been studied. It has been established that the equivalent diameter of a grain of sand has a significant influence on the longitudinal pressure distribution in the duct. The influence of chemical kinetics on the flow structure in separation zones within the duct is demonstrated. [ABSTRACT FROM AUTHOR]
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- 2023
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161. Consumer Fairness Concerns and Dynamic Pricing in a Channel.
- Author
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Diao, Wen, Harutyunyan, Mushegh, and Jiang, Baojun
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TIME-based pricing ,WHOLESALE prices ,CONSUMERS ,RETAIL industry ,FAIRNESS ,PRICE cutting - Abstract
Effect of consumer fairness concerns on wholesale and retail price dynamics and manufacturer and retailer profits. The extant literature has shown that when a firm increases its price because of increased demand, some consumers may have fairness concerns and experience psychological disutility when buying the firm's product. This paper provides a two-period model to study the effects of consumers' fairness concerns on firms' dynamic pricing strategies and profits in a channel. Our analysis reveals a strategic link between the two periods—the retailer has a cost-reduction incentive of lowering its first-period price to induce the manufacturer to reduce the wholesale price in the second period. When the retailer's cost-reduction incentive prevails, in equilibrium, the retail price stays unchanged, whereas the wholesale price decreases over time. Hence, our results provide an alternative explanation for the empirical observation that retail prices typically do not decrease when wholesale prices do. Further, we find that a higher demand increase in the second period can lead to a decrease in both wholesale and retail prices. Importantly, we show that consumer fairness concerns can result in a win-win outcome for the manufacturer and the retailer, which suggests that firms may prefer not using tactics such as price framing to alleviate fairness concerns. History: Ganesh Iyer served as the senior editor and Dave Godes served as associate editor for this article. Supplemental Material: The online appendix is available at https://doi.org/10.1287/mksc.2022.1395. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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162. Optimization of Spillway Design of Reconstructed Shavan Dam Using Numerical 2D-Modeling.
- Author
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Borisova, N. M. and Belikov, V. V.
- Abstract
The design of an emergency labyrinth spillway, which must be constructed for the further safe use of the Shavan dam, is analyzed. Two computer hydrodynamic models were developed: (1) an initial model of the emergency spillway with a front width of 50 m and a semicircular channel in plan view; (2) an improved emergency spillway with a front width of 60 m and an almost rectilinear channel. The research was carried out by numerical hydrodynamic modeling methods using the domestic high-precision STREAM 2D CUDA software complex. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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163. Whole-cell patch-clamp recording and parameters.
- Author
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Kodirov, Sodikdjon A.
- Abstract
The patch-clamp technique represents an electrophysiology type of method. This is one of several insightful approaches with five major configurations, namely a loose patch, cell-attached (also known as on-cell), whole-cell, inside-out, and outside-out modes. The patch-clamp method is more advanced compared to classical electrophysiology since it elucidates single-channel activation in a tiny portion of the membrane in addition to action potential (AP), junction potential (JP), endplate potential (EP), electrical coupling between two adjacent cells via Gap junction hemi-channels, excitatory/inhibitory postsynaptic potentials, and resting membrane potential (RMP). In fact, a malfunction of only one channel or even one component will alter AP amplitude or duration in vitro. If parameters are inferred appropriately and recordings are performed properly, the patch-clamp trace readouts and results are robust. The main hallmarks of currents via voltage-dependent calcium (Cav), hyperpolarization-activated cyclic nucleotide gated non-selective cation (HCN), inwardly rectifying potassium (Kir), voltage-dependent potassium (Kv), and voltage-dependent sodium (Nav) channels are similar and tractable among cells even when they are derived from evolutionary distinct organs and species. However, the size of the membrane area, where the functional subunits reside, and current magnitudes vary among cells of the same type. Therefore, dividing current magnitudes by cell capacitance– current density enables the estimate of functional and active channels relative to recorded cytoplasmic membrane area. Since the patch-clamp recordings can be performed in both current- and voltage-clamp modes, the action potential or spike durations can be adequately elucidated. Sometimes, optical methods are preferred to patch-clamp electrophysiology, but the obtained signals and traces are not robust. Finally, not only an alternans of AP durations, but also that of 'action potential shape' is observed with electrophysiology. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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164. Territorio liquido. La roggia Fusia e la morfogenesi della Franciacorta occidentale in antico regime.
- Author
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Dotti, Marco
- Abstract
The aim of this article is to study the process of "locality production", focusing on the western Venetian terraferma and the municipality of Rovato. Since the 14th century, the construction of an important waterworks has significantly influenced the development of this area. The canal, called Fusia, made a previously sparsely populated area fertile, rich and populous, changing both the geographical and political hierarchies of the area. The Fusia Canal became the most important common source of water, but at the same time it was the cause of fierce struggles between communities and territorial bodies, as well as between different social bodies. The town of Rovato benefited greatly from the canal and established itself as the most important town in Franciacorta. The collective resources (water, mills, etc.) were shared and managed by a group of families, called «originari», who had contributed to the acquisition of the canal, between the 14th and 15th centuries. The institutions of the community were modelled in accordance with the management of the commons sources and this made them very successful in protecting the rights on Fusia towards other communities and individuals. However, internal conflicts were fuelled by this institutional arrangement, which remained in place until the end of the old regime. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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165. Efficiency of two decoders based on hash techniques and syndrome calculation over a Rayleigh channel.
- Author
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Alaoui, Seddiq El Kasmi, Chiba, Zouhair, Faham, Hamza, El Assad, Mohammed, and Nouh, Said
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RAYLEIGH fading channels ,ADDITIVE white Gaussian noise ,VIDEO coding ,BLOCK codes ,CONGRUENCES & residues ,LINEAR codes - Abstract
The explosive growth of connected devices demands high quality and reliability in data transmission and storage. Error correction codes (ECCs) contribute to this in ways that are not very apparent to the end user, yet indispensable and effective at the most basic level of transmission. This paper presents an investigation of the performance and analysis of two decoders that are based on hash techniques and syndrome calculation over a Rayleigh channel. These decoders under study consist of two main features: a reduced complexity compared to other competitors and good error correction performance over an additive white gaussian noise (AWGN) channel. When applied to decode some linear block codes such as Bose, Ray-Chaudhuri, and Hocquenghem (BCH) and quadratic residue (QR) codes over a Rayleigh channel, the experiment and comparison results of these decoders have shown their efficiency in terms of guaranteed performance measured in bit error rate (BER). For example, the coding gain obtained by syndrome decoding and hash techniques (SDHT) when it is applied to decode BCH (31, 11, 11) equals 34.5 dB, i.e., a reduction rate of 75% compared to the case where the exchange is carried out without coding and decoding process. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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166. METHOD FOR CALCULATING THE DISSIPATION ENERGY DURING THE FLOW OF GENERALIZED-DISPLACED FLUID IN THE CHANNELS OF TECHNOLOGICAL EQUIPMENT.
- Author
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Biletsky, Eduard V., Petrenko, Elena V., and Semeniuk, Dmitrij P.
- Subjects
ENERGY dissipation ,ECONOMIC indicators ,AUTOMATIC screw machines ,BOUNDARY value problems ,EQUIPMENT & supplies - Abstract
This paper considers the problem of determining the dissipation energy during the flow of a generalized-displaced fluid in the channels of technological equipment. It is known that during the flow of highly viscous non-Newtonian fluids, the problem of heating this substance arises. This is primarily due to the fact that during the transportation of the material, the dissipation mechanism takes place, which leads to overheating of the material. In its turn, this affects the changes in the physical and chemical properties of the material and the technical and economic indicators of the corresponding equipment. We propose a method for calculating the dissipation energy during the flow of a generalized-displaced fluid in the channels of screw machines. To solve this problem, we used the superposition method to construct fields of larger dimensions from fields of smaller dimensions with different boundary conditions. A channel of flat and rectangular shape is considered. Fluid movement is carried out in the longitudinal and longitudinal-transverse directions of the channel. To calculate the amount of energy dissipation of a generalizeddisplaced fluid, it is necessary to first divide the channel sections into sections with different expressions for the flow rate. At the same time, each of the subareas consists of two curvilinear triangles and one rectangle. The mandatory steps of the calculations are the breakdown of the rectangle of the cross section of the straight channel, and the calculation of the integrals from the derivatives of the velocity. The proposed method allows to calculate the energy of dissipative heat generation when calculating the optimal parameters of technological equipment. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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167. Influence of notched baffles on aerothermal performance behaviors in a channel
- Author
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Arnut Phila, Warin Keaitnukul, Smith Eiamsa-ard, Paisarn Naphon, Naoki Maruyama, Masafumi Hirota, and Varesa Chuwattanakul
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Channel ,Heat transfer enhancement ,Notched baffle ,Solid baffle ,Transverse baffle ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The proper designs of modified heat transfer surfaces or turbulence enhancement inserts for heat transfer augmentation are extremely important for improving overall aerothermal performances relating to the energy-saving capabilities of thermal systems. A major challenge is to control friction loss as little as possible while maintaining reasonable heat transfer enhancement. Transverse baffles with rectangular notches or notched baffles (NBs) were applied for improving aerothermal performance in a channel with a constant aspect ratio of 3.75 while notch height-to-baffle height ratio (a/e) ranged from 0.125 to 0.5. Reynolds number ranged from 6000 to 24,000, in experiments. Heat transfer enhancement, pressure loss, and aerothermal performance in a rectangular channel with notched baffles were examined. Compared to the solid transverse baffle (SB, a/e = 0), the NBs with a/e = 0.125 increased the heat transfer rate while lessening the pressure loss, as shown by the experimental findings. Obviously, Nusselt number, friction factor and aerothermal performance increased as the a/e ratio decreased. The NBs with the smallest notch height-to-baffle height ratio (a/e = 0.125) exhibited the highest aerothermal performance of 1.17, which can be attributed to the efficient heat transfer enhancement by the strong multi-jet impingements and the moderate friction loss penalty resulting from the presence of notches (spaces) on the baffles.
- Published
- 2023
- Full Text
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168. Impact of viscous dissipation and entropy generation on cold liquid via channel with porous medium by analytical analysis
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Y. Masthanaiah, Nainaru Tarakaramu, M. Ijaz Khan, A. RushiKesava, Sana Ben Moussa, Bandar M. Fadhl, Sherzod Shukhratovich Abdullaev, and Sayed M. Eldin
- Subjects
Magnetic field ,Viscous dissipation ,Couple stress liquid ,Entropy generation ,Porous medium ,Channel ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In the current investigation, it is examined numerically entropy generation (EG) on inherent irreversibility motion of couple stress cold liquid with porous medium via Horizontal channel in presence of viscous dissipation. Present work was studied heat generation on couple stress liquid with porous channel. This work considerable importance in many industrial applications like “Control Mechanism in Material Manufacturing”, “Manufactures of Electronic Chips”, “Crystal Formation”, “Scientific Treatment Problems of Irrigation”, “Soil Erosion and tile drainage” are the present focus of development of channel motion. The formulated physical liquid equations are subsequently calculated by shooting technique with R-K-F (“Runge-Kutta Fehlberg”) scheme. The velocity, temperature as predicted via graphically. we found the velocity dwindle, temperature high production by an escalating statistical value of K (“Couple Stress Parameter”), Ec (“Eckert number”) and Q (“Heat Generation parameter”) respectively. Gradient constraint in addition to improve by an enhancement into Bejan number for various values of “pressure gradient parameter”.
- Published
- 2023
- Full Text
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169. Bipolar Plasticity in Synaptic Transistors: Utilizing HfSe2 Channel with Direct-Contact HfO2 Gate Dielectrics
- Author
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Jie Lu, Zeyang Xiang, Kexiang Wang, Mengrui Shi, Liuxuan Wu, Fuyu Yan, Ranping Li, Zixuan Wang, Huilin Jin, and Ran Jiang
- Subjects
plasticity ,hafnium dioxide ,channel ,interlay ,Inorganic chemistry ,QD146-197 - Abstract
The investigation of dual-mode synaptic plasticity was conducted in thin-film transistors (TFTs) featuring an HfSe2 channel, coupled with an oxygen-deficient (OD)-HfO2 layer structure. In these transistors, the application of negative gate pulses resulted in a notable increase in the post-synaptic current, while positive pulses led to a decrease. This distinctive response can be attributed to the dynamic interplay of charge interactions, significantly influenced by the ferroelectric characteristics of the OD-HfO2 layer. The findings from this study highlight the capability of this particular TFT configuration in closely mirroring the intricate functionalities of biological neurons, paving the way for advancements in bio-inspired computing technologies.
- Published
- 2024
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170. Dipole Oscillations along Principal Coordinates in a Frozen Channel in the Context of Symmetric Linear Thickness of Porous Ice
- Author
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Konstantin Shishmarev, Tatyana Sibiryakova, Kristina Naydenova, and Tatyana Khabakhpasheva
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dipole ,oscillations ,channel ,ice plate ,porous ice ,ice deflections ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 ,Oceanography ,GC1-1581 - Abstract
The problem of periodic oscillations of a dipole, specifically its strength, along the principal axes in a three-dimensional frozen channel is considered. The key points of the problem are taking into account the linear thickness of ice across the channel and ice porosity within Darcy’s law. The fluid in the channel is inviscid and incompressible; the flow is potential. It is expected that the oscillations of a small radius dipole well approximate the oscillations of a small radius sphere at a sufficient depth of immersion of the dipole. It was found that during oscillations along the channel and vertical oscillations, waves are generated in the channel, propagating along the channel with a frequency equal to the frequency of dipole oscillations. These waves decay far from the dipole, and the rate of decay depends on the porosity coefficient.
- Published
- 2024
- Full Text
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171. The Bright Side of Having an Enemy.
- Author
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Harutyunyan, Mushegh and Jiang, Baojun
- Subjects
ECONOMIC competition ,MANUFACTURER-dealer relationship ,RETAIL industry ,MARKET entry ,MARKET exit ,PRICING - Abstract
Conventional wisdom suggests that more intense competition will lower firms' profits. The authors show that this may not hold in a channel setting with exclusive retailers. They find that a manufacturer and its retailer can both become worse off if their competing manufacturer and retailer with quality-differentiated products exit the market. Put differently, in a channel setting, more intense competition can be all-win for the manufacturer, the retailer, and the consumers. Interestingly, a high-quality manufacturer can benefit from an increase in its competitor's perceived quality (e.g., due to favorable product reviews from consumers or third-party rating agencies). In other words, a manufacturer may prefer a strong rather than a weak enemy, and the manufacturer can have an incentive to help its competitor improve product quality or remain in the market. Furthermore, the authors show that a multiproduct monopolist manufacturer with an exclusive retailer may make higher profits by spinning off a product into a competing manufacturer that has its own retail channel, even without accounting for any proceeds from the spinoff. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
172. Cryo-EM structure of OSCA1.2 from Oryza sativa elucidates the mechanical basis of potential membrane hyperosmolality gating
- Author
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Maity, Koustav, Heumann, John M, McGrath, Aaron P, Kopcho, Noah J, Hsu, Po-Kai, Lee, Chang-Wook, Mapes, James H, Garza, Denisse, Krishnan, Srinivasan, Morgan, Garry P, Hendargo, Kevin J, Klose, Thomas, Rees, Steven D, Medrano-Soto, Arturo, Saier, Milton H, Piñeros, Miguel, Komives, Elizabeth A, Schroeder, Julian I, Chang, Geoffrey, and Stowell, Michael HB
- Subjects
Biochemistry and Cell Biology ,Biological Sciences ,1.1 Normal biological development and functioning ,Underpinning research ,Generic health relevance ,Amino Acid Sequence ,Anoctamins ,Arabidopsis ,Arabidopsis Proteins ,Calcium Channels ,Cryoelectron Microscopy ,Cytoplasm ,Mass Spectrometry ,Membrane Potentials ,Oryza ,Osmotic Pressure ,Protein Conformation ,Water ,osmotic stress ,channel ,structure ,cryo-EM ,rice - Abstract
Sensing and responding to environmental water deficiency and osmotic stresses are essential for the growth, development, and survival of plants. Recently, an osmolality-sensing ion channel called OSCA1 was discovered that functions in sensing hyperosmolality in Arabidopsis Here, we report the cryo-electron microscopy (cryo-EM) structure and function of an OSCA1 homolog from rice (Oryza sativa; OsOSCA1.2), leading to a model of how it could mediate hyperosmolality sensing and transport pathway gating. The structure reveals a dimer; the molecular architecture of each subunit consists of 11 transmembrane (TM) helices and a cytosolic soluble domain that has homology to RNA recognition proteins. The TM domain is structurally related to the TMEM16 family of calcium-dependent ion channels and lipid scramblases. The cytosolic soluble domain possesses a distinct structural feature in the form of extended intracellular helical arms that are parallel to the plasma membrane. These helical arms are well positioned to potentially sense lateral tension on the inner leaflet of the lipid bilayer caused by changes in turgor pressure. Computational dynamic analysis suggests how this domain couples to the TM portion of the molecule to open a transport pathway. Hydrogen/deuterium exchange mass spectrometry (HDXMS) experimentally confirms the conformational dynamics of these coupled domains. These studies provide a framework to understand the structural basis of proposed hyperosmolality sensing in a staple crop plant, extend our knowledge of the anoctamin superfamily important for plants and fungi, and provide a structural mechanism for potentially translating membrane stress to transport regulation.
- Published
- 2019
173. Structure optimization of continuous casting tundish with channel-type induction heating using mathematical modeling
- Author
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Yang Bin, Liu Kun, Lei Hong, and Han Peng
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channel ,induction heating ,chamber ,inclusion ,flow ,Technology ,Chemical technology ,TP1-1185 ,Chemicals: Manufacture, use, etc. ,TP200-248 - Abstract
There are few studies on the shape and structure of the channel-type induction heating tundish on multi-physics field. Computational fluid dynamics has been used to study the influence of the structure of the tundish on the macroscopic transport behavior of the tundish with channel induction heating. The results show that increasing the depth of the molten pool is conducive to dynamic behavior of multiphase, the deeper the molten pool, the larger the active area, the longer residence time, the more inclusions removal and the higher ratio of plug to dead volume. Meanwhile, the larger the channel diameter, the more inclusions removal in the receiving chamber and channel. The channel induction heating has enough ability to increase the superheat and temperature compensate for the heat loss caused by the excessive residence time of the molten steel in the tundish. The change in the channel structure is crucial to the macroscopic transport behavior of the fluid. The change in channel diameter has the greatest effect on the multi-physics field in the molten pool.
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- 2022
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174. Clinical efficacy and safety of posterior minimally invasive surgery in cervical spondylosis: a systematic review
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Junqiao Lv, Jun Mei, Xiaoning Feng, Xuefeng Tian, and Lin Sun
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Cervical spondylosis ,Posterior minimally invasive surgery ,Systematic review ,Percutaneous endoscopy ,Channel ,Keyhole ,Orthopedic surgery ,RD701-811 ,Diseases of the musculoskeletal system ,RC925-935 - Abstract
Abstract Background Posterior minimally invasive surgery has been increasingly used in in recent years for the clinical treatment of cervical spondylosis. However, this treatment remains challenging and has not been comprehensively reported. The aim of this study was to provide a systematic review of posterior minimally invasive treatment for cervical spondylosis to demonstrate the clinical efficacy and safety of this procedure. Method We collected information from patients with myelopathy or radiculopathy cervical spondylosis who underwent posterior minimally invasive surgery and verified the clinical efficacy and safety of these surgeries with different measurement indicators from five electronic databases: the Nurick, visual analog scale score, Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), EuroQol Five Dimensions Questionnaire (EQ-5D) score, Short-Form Health Survey Physical Component Summary (SF12-PCS) questionnaire score, Short-Form Health Survey Mental Component Summary (SF12-MCS) questionnaire score, and the MOS item short form health survey (HF-36) score. The decompression effect, cervical spine stability, average surgery time, surgical blood loss volume, length of hospital stay, and related complications were included in the descriptive analysis. Reporting of this protocol followed the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines checklist. Results We identified 14 observational studies of cervical spondylosis with 479 patients, mainly including 197 cases of myelopathy and 207 cases of radiculopathy. Channel and endoscopic techniques were used. This study was certified by PROSPERO: CRD42021290074. Significant improvements in the quantitative indicators (Neck-VAS in 9 studies, JOA in 7 studies, NDIs in 5 studies, Nurick, ARM-VAS, and EQ-5D in 2 studies each, and the SF12-PCS, SF12-MCS, and HF-36 in 1 study each) were observed between pre- and postoperation (P
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- 2022
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175. Measuring the through-plane and in-plane oxygen apparent diffusion coefficients in the gas diffusion layer
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Keguang Yao, Tiehan Long, Yajun Wang, Xiao-Zi Yuan, Yao Yao, and Haijiang Wang
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proton exchange membrane fuel cells ,gas diffusion layer ,oxygen diffusion coefficients ,land ,channel ,General Works - Abstract
Accurately predicting oxygen mass transport resistance and current distribution in fuel cells requires significant knowledge of oxygen diffusion coefficients in both in-plane and through-plane directions. However, there are few methods for measuring in-plane oxygen diffusion coefficients, which are important parameters for simulating oxygen flux distribution in gas diffusion layers (GDLs). In this study, we establish measurement methods and calculations for both in-plane and through-plane oxygen diffusion coefficients. Using in-house designed cells, we measure the in-plane and through-plane oxygen apparent diffusion coefficients of a commercial carbon paper (AvCarb EP40) at various torques and gas flow rates. We also simulate oxygen flux distributions in the GDL under each torque and gas flow rate. Our results show that the channel part is the major contributor to total oxygen flux at high torque conditions and that an increase in torque leads to a decrease in the contribution from the land part. Simulation results also suggest that a higher gas flow rate and lower torque contribute to a more uniform distribution of oxygen flux in the GDL.
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- 2023
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176. Viewing river corridors through the lens of critical zone science
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Adam S. Wymore, Adam S. Ward, Ellen Wohl, and Judson W. Harvey
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river corridor ,critical zone ,watersheds ,floodplain ,channel ,ecosystems ,Environmental technology. Sanitary engineering ,TD1-1066 - Abstract
River corridors integrate the active channels, geomorphic floodplain and riparian areas, and hyporheic zone while receiving inputs from the uplands and groundwater and exchanging mass and energy with the atmosphere. Here, we trace the development of the contemporary understanding of river corridors from the perspectives of geomorphology, hydrology, ecology, and biogeochemistry. We then summarize contemporary models of the river corridor along multiple axes including dimensions of space and time, disturbance regimes, connectivity, hydrochemical exchange flows, and legacy effects of humans. We explore how river corridor science can be advanced with a critical zone framework by moving beyond a primary focus on discharge-based controls toward multi-factor models that identify dominant processes and thresholds that make predictions that serve society. We then identify opportunities to investigate relationships between large-scale spatial gradients and local-scale processes, embrace that riverine processes are temporally variable and interacting, acknowledge that river corridor processes and services do not respect disciplinary boundaries and increasingly need integrated multidisciplinary investigations, and explicitly integrate humans and their management actions as part of the river corridor. We intend our review to stimulate cross-disciplinary research while recognizing that river corridors occupy a unique position on the Earth's surface.
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- 2023
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177. Qualitative modeling of solar panel cooling by nanofluid jets: Heat transfer and second law analysis
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Naifa S. Alatawi, Abeer M. Almutairi, S.A. Khalil, Asma Obaidallah Alatawi, Wejdan Al-Anazi, and Mourad Magherbi
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Heat transfer ,Created entropy ,Mixed convection ,Nanofluid ,Channel ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The present paper highlights heat transfer and entropy generation due to mixed convection for an inclined channel. The channel is heated by its upper wall and cooled by two jets of nanofluids penetrating through its lower wall. The studied configuration is chosen to model, in qualitative way, a cooling system for photovoltaic panel. The set of partial differential equations that governing the flow was numerically solved using COMSOL software. Effects of the inclination angle of the channel, Reynolds number and nanoparticles fraction, on heat transfer, hydrodynamic and created entropy are examined. The inclination angle, the Reynolds number and the nanoparticle fraction are ranging from 0° to 30°, from 50 to 150 and from 0% to 8% respectively. It was found that the effect of the angle of inclination, on heat transfer and thermal irreversibility, is weak and that it cannot exceed 2%. Whereas the nanofluid concentration and the Reynolds numbers alter at once the created entropy and the heat transfer. Results show an increase of nearly 15% of Nusselt number and thermal irreversibility when the nanoparticle concentration reaches 8%. The local irreversibility maps reveal that the created entropy is significantly localized at the impact locations of the cooling jets. Since irreversibility is synonymous with the aging of the system, which naturally leads to usury, it can be concluded that the channel may be damaged at these locations.
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- 2023
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178. Role of voltage-gated proton channel (Hv1) in cancer biology
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Juan J. Alvear-Arias, Antonio Pena-Pichicoi, Christian Carrillo, Miguel Fernandez, Tania Gonzalez, Jose A. Garate, and Carlos Gonzalez
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Hv1 ,cancer ,tumor ,channel ,proton ,pH ,Therapeutics. Pharmacology ,RM1-950 - Abstract
The acid-base characteristics of tumor cells and the other elements that compose the tumor microenvironment have been topics of scientific interest in oncological research. There is much evidence confirming that pH conditions are maintained by changes in the patterns of expression of certain proton transporters. In the past decade, the voltage-gated proton channel (Hv1) has been added to this list and is increasingly being recognized as a target with onco-therapeutic potential. The Hv1 channel is key to proton extrusion for maintaining a balanced cytosolic pH. This protein-channel is expressed in a myriad of tissues and cell lineages whose functions vary from producing bioluminescence in dinoflagellates to alkalizing spermatozoa cytoplasm for reproduction, and regulating the respiratory burst for immune system response. It is no wonder that in acidic environments such as the tumor microenvironment, an exacerbated expression and function of this channel has been reported. Indeed, multiple studies have revealed a strong relationship between pH balance, cancer development, and the overexpression of the Hv1 channel, being proposed as a marker for malignancy in cancer. In this review, we present data that supports the idea that the Hv1 channel plays a significant role in cancer by maintaining pH conditions that favor the development of malignancy features in solid tumor models. With the antecedents presented in this bibliographic report, we want to strengthen the idea that the Hv1 proton channel is an excellent therapeutic strategy to counter the development of solid tumors.
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- 2023
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179. A Channel Allocation Method Considering the Asymmetry of Available Channels for Centralized Underwater Cognitive Acoustic Networks.
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Yun, Changho
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RESOURCE allocation , *COGNITIVE radio , *FAIRNESS - Abstract
Due to the unpredictable presence of Non-Cognitive Users (NCUs) in the time and frequency domains, the number of available channels (i.e., channels where no NCUs exist) and corresponding channel indices per Cognitive User (CU) may differ. In this paper, we propose a heuristic channel allocation method referred to as Enhanced Multi-Round Resource Allocation (EMRRA), which employs the asymmetry of available channels in existing MRRA to randomly allocate a CU to a channel in each round. EMRRA is designed to enhance the overall spectral efficiency and fairness of channel allocation. To do this, the available channel with the lowest redundancy is primarily selected upon allocating a channel to a CU. In addition, when there are multiple CUs with the same allocation priority, the CU with the smallest number of available channels is chosen. We execute extensive simulations in order to investigate the effect of the asymmetry of available channels on CUs and compare the performance of EMRRA to that of MRRA. As a result, in addition to the asymmetry of available channels, it is confirmed that most of the channels are simultaneously available to multiple CUs. Furthermore, EMRRA outperforms MRRA in terms of the channel allocation rate, fairness, and drop rate and has a slightly higher collision rate. In particular, EMRRA can remarkably reduce the drop rate compared to MRRA. [ABSTRACT FROM AUTHOR]
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- 2023
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180. Decreased heat sensitivity of lungfish TRPV1 revealed by the heterologous expression system.
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Hori, Shogo and Saitoh, Osamu
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TRPV cation channels , *AMPHIBIANS , *HIGH temperatures - Abstract
In this study, we focused on TRPV1 of African lungfish, Protopterus annectens. During drought at high temperature, African lungfish can survive by undergoing into aestivation in mud cocoons. Therefore, lungfish is considered to have some specialized heat-sensor, TRPV1, for heat tolerance. Further, lungfish which shares similarities with fishes and amphibians, is one of important species for investigating the fish-tetrapod transition. Since fish TRPV1 and tetrapod TRPV1 have some differences, character of lungfish TRPV1 attracts attention. Here, we first cloned TRPV1 paralogue from lungfish, Protopterus annectens (lfTRPV1) and determined the chemical and thermal sensitivities of lfTRPV1 by two-electrode voltage clamp method using frog oocytes. We detected activation of lfTRPV1 by acid and 2-APB, but capsaicin-induced activation was not observed. The sensitivity to acid of lfTRPV1 was similar to that of rat TRPV1 (rTRPV1), but the 2-APB sensitivity of lfTRPV1 was relatively weaker than rTRPV1. Heat stimulation up to 44 °C did not activate lfTRPV1 and the heat-activation was not detected even on acid condition of pH6. This dramatically decreased heat-sensitivity of TRPV1 may contribute the heat tolerance of African lungfish. Moreover, this might be the property of ancient tetrapod-type TRPV1 gene. • We first cloned TRPV1 paralogue from lungfish. • Lungfish TRPV1 was activated by acid and 2-APB, but not by capsaicin. • Heat stimulation did not activate lungfish TRPV1. [ABSTRACT FROM AUTHOR]
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- 2023
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181. Multi-Channel Assessment Policies for Energy-Efficient Data Transmission in Wireless Underground Sensor Networks.
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Soundararajan, Rajasoundaran, Stanislaus, Prince Mary, Ramasamy, Senthil Ganesh, Dhabliya, Dharmesh, Deshpande, Vivek, Sehar, Sountharrajan, and Bavirisetti, Durga Prasad
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WIRELESS sensor networks , *MULTICHANNEL communication , *NONLINEAR regression , *GENERATIVE adversarial networks , *SIGNAL-to-noise ratio , *DATA transmission systems , *SUPPORT vector machines - Abstract
Wireless Underground Sensor Networks (WUGSNs) transmit data collected from underground objects such as water substances, oil substances, soil contents, and others. In addition, the underground sensor nodes transmit the data to the surface nodes regarding underground irregularities, earthquake, landslides, military border surveillance, and other issues. The channel difficulties of WUGSNs create uncertain communication barriers. Recent research works have proposed different types of channel assessment techniques and security approaches. Moreover, the existing techniques are inadequate to learn the real-time channel attributes in order to build reactive data transmission models. The proposed system implements Deep Learning-based Multi-Channel Learning and Protection Model (DMCAP) using the optimal set of channel attribute classification techniques. The proposed model uses Multi-Channel Ensemble Model, Ensemble Multi-Layer Perceptron (EMLP) Classifiers, Nonlinear Channel Regression models and Nonlinear Entropy Analysis Model, and Ensemble Nonlinear Support Vector Machine (ENLSVM) for evaluating the channel conditions. Additionally, Variable Generative Adversarial Network (VGAN) engine makes the intrusion detection routines under distributed environment. According to the proposed principles, WUGSN channels are classified based on the characteristics such as underground acoustic channels, underground to surface channels and surface to ground station channels. On the classified channel behaviors, EMLP and ENLSVM are operated to extract the Signal to Noise Interference Ratio (SNIR) and channel entropy distortions of multiple channels. Furthermore, the nonlinear regression model was trained for understanding and predicting the link (channel behaviors). The proposed DMCAP has extreme difficulty finding the differences of impacts due to channel issues and malicious attacks. In this regard, the VGAN-Intrusion Detection System (VGAN-IDS) model was configured in the sensor nodes to monitor the channel instabilities against malicious nodes. Thus, the proposed system deeply analyzes multi-channel attribute qualities to improve throughput in uncertain WUGSN. The testbed was created for classified channel parameters (acoustic and air) with uncertain network parameters; the uncertainties of testbed are considered as link failures, noise distortions, interference, node failures, and number of retransmissions. Consequently, the experimental results show that DMCAP attains 10% to 15% of better performance than existing systems through better throughput, minimum retransmission rate, minimum delay, and minimum energy consumption rate. The existing techniques such as Support Vector Machine (SVM) and Random Forest (RF)-based Classification (SMC), Optimal Energy-Efficient Transmission (OETN), and channel-aware multi-path routing principles using Reinforcement Learning model (CRLR) are identified as suitable for the proposed experiments. [ABSTRACT FROM AUTHOR]
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- 2023
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182. Mapping Drainage Ditches in Forested Landscapes Using Deep Learning and Aerial Laser Scanning.
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Lidberg, William, Paul, Siddhartho Shekhar, Westphal, Florian, Richter, Kai Florian, Lavesson, Niklas, Melniks, Raitis, Ivanovs, Janis, Ciesielski, Mariusz, Leinonen, Antti, and Ågren, Anneli M.
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DITCHES , *AIRBORNE lasers , *FORESTED wetlands , *DEEP learning , *LAND management , *WETLAND hydrology , *WETLAND soils - Abstract
Extensive use of drainage ditches in European boreal forests and in some parts of North America has resulted in a major change in wetland and soil hydrology and impacted the overall ecosystem functions of these regions. An increasing understanding of the environmental risks associated with forest ditches makes mapping these ditches a priority for sustainable forest and land use management. Here, we present the first rigorous deep learning–based methodology to map forest ditches at regional scale. A deep neural network was trained on airborne laser scanning data (ALS) and 1,607 km of manually digitized ditch channels from 10 regions spread across Sweden. The model correctly mapped 86% of all ditch channels in the test data, with a Matthews correlation coefficient of 0.78. Further, the model proved to be accurate when evaluated on ALS data from other heavily ditched countries in the Baltic Sea Region. This study leads the way in using deep learning and airborne laser scanning for mapping fine-resolution drainage ditches over large areas. This technique requires only one topographical index, which makes it possible to implement on national scales with limited computational resources. It thus provides a significant contribution to the assessment of regional hydrology and ecosystem dynamics in forested landscapes. [ABSTRACT FROM AUTHOR]
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- 2023
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183. Investigation of drag and heat flux reduction induced by a novel combinational spike-aerodisk and channel concept for hypersonic blunt body.
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Guo, Jian, Fang, Shuzhou, Wang, Ziyu, Ni, Zijian, and Xu, Yang
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DRAG reduction , *HEAT flux , *MACH number , *DRAG coefficient , *DRAG (Aerodynamics) , *JETS (Fluid dynamics) - Abstract
For the drag and heat flux reduction of hypersonic blunt body, a novel combinational spike-aerodisk and channel concept has been proposed. The high pressure air behind the bow shock flows into the channel at the head of the aerodisk, and then sprays out through the lateral jet in the middle of the spike. The Reynolds-averaged Navier-Stokes (RANS) equations coupled with the shear stress transport (SST) k - ω turbulence model have been employed to simulate the flow field. The numerical results reveal that compared with the spike-aerodisk, with the application of the channel, the lateral jet pushes the separated shock wave away from the spike. The range of the recirculation zone between the shear layer and the spike is increased, and the intensity of the reattached shock wave is significantly weakened, so the drag and heat flux reduction properties of the combinational configuration are significantly improved. The influences of the channel convergent half angle and lateral jet location on the flow field, drag and heat flux reduction properties are investigated thoroughly. When the channel convergent half angle is appropriate and the location of the lateral jet is close to the middle of the spike, the drag and heat flux reduction effect becomes better. Besides, with the increase of the Mach number and the decrease of the flying height, the drag and heat flux reduction performance become more significant. In the research range, the combinational configuration in which the convergent half angle is 60° and the lateral jet is located in the middle of the spike has a better overall effect of drag and heat flux reduction, and the effect reaches the best when the Mach number is 6 and the flying height is 20 km. Compared with the spike-aerodisk, the total drag coefficient of the configuration is reduced by 12.95%, and the peak value of Stanton number along the blunt body surface is reduced by 35.19%. • A novel combinational spike-aerodisk and channel concept was numerically investigated. • The combinational concept has better performance in both drag and heat flux reduction. • Effects of channel convergent half angle and lateral jet location on drag and heat flux reduction were studied. • Variation laws of drag and heat flux reduction under different Mach numbers and flight altitudes were analyzed. [ABSTRACT FROM AUTHOR]
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- 2023
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184. Effect of triangular porous layer on the transfer of heat and species in a channel‐open cavity.
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Al‐Hassan, Ali Q. Abd and Ismael, Muneer A.
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HEAT transfer , *HEAT convection , *NUSSELT number , *LAMINAR flow , *FINITE element method , *RAYLEIGH number - Abstract
This paper addresses the heat and species transfer in a composite cavity linked with a horizontal channel. The cavity comprises a triangular porous layer and one of its vertical sides is exposed to a high temperature and concentration. The mathematical conservation equations are solved numerically using the Galerkin finite element method. The ranges of Reynolds and Richardson numbers are taken to ascertain laminar flow, Re = 50–250 and Ri = 0.1–100. The size of the porous layer is quantified by the thickness of the porous layer Hp = 0.25–1. The problem is studied for two cases of heat and species sources; the opposing case, when the active side is on the right, and assisting case, when the active side is on the left. Results reveal that for specified conditions, the triangular porous layer increases Nusselt and Sherwood numbers by 30% and 32%, respectively, more than the horizontal porous layer. The opposing case gives maximum convective heat transfer, where for Ri = 0.01, the Nusselt number is higher by 61% and 134% for Re = 50 and 250, respectively, while for Ri = 100, the percentages increase are 67% and 43%. [ABSTRACT FROM AUTHOR]
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- 2023
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185. Seafloor pockmarks on the South Westland margin of the South Island/Te Waipounamu, Aotearoa New Zealand.
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Maier, Katherine L., Orpin, Alan R., and Neil, Helen
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SUBMARINE valleys , *TURBIDITY currents , *CONTINENTAL slopes , *WATER depth , *MULTIBEAM mapping , *SUBMARINE fans - Abstract
Enclosed depressions, termed pockmarks, are widespread seafloor morphologies, commonly associated with fluid seepage. This study provides the first detailed documentation of pockmarks offshore the South Westland margin of the South Island/Te Waipounamu, Aotearoa New Zealand. Pockmarks are identified from multibeam bathymetry (25-m grid) through manual and semi-automated selection in water depths of 100–2600 m. Pockmarks are most concentrated at 400–850 m water depth on continental slope areas between submarine canyons. A continuum of pockmark morphologies includes – (1) large (>0.5 km2 area) and irregularly shaped pockmarks above partially infilled channels; (2) small and circular pockmarks (∼100–200 m diameter; ∼0.008–0.03 km2 area) occurring between canyons; and (3) elongated and intermediate size pockmarks, generally oriented along-slope and often occurring above buried sediment waves. Elongated pockmarks appear to have been modified by near-seafloor oceanographic and/or turbidity current flows. Pockmark features occur across many locations around Aotearoa, including both the eastern and western margins. Some similar pockmark morphologies are identified in these different tectonic, sedimentary, and oceanographic settings, suggesting that there may be some similarity in formative mechanisms, but clear mechanisms leading to their formation remain enigmatic. [ABSTRACT FROM AUTHOR]
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- 2023
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186. A Comparative Study of Entropy Generation Analysis Through Cartesian and Cylindrical Annulus Geometries.
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Sakly, Abir and Said, Nejla Mahjoub
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FORCED convection , *MASS transfer , *MASS transfer coefficients , *RADIATIVE transfer equation , *ENTROPY , *FINITE volume method , *LIQUID films , *RAY tracing - Abstract
This research paper presents a comparative study dealing with entropy generation analysis in Cartesian and cylindrical annulus geometries. This numerical investigation involves heat and mass transfer coupled with forced convection and gas radiation in a semitransparent medium during the evaporation of a thin liquid film. The systems of equations are solved with interfacial and boundary conditions using an implicit finite volume method by the tridiagonal matrix algorithm method. The radiative transfer equation (RTE) was solved by the Ray tracing model. The statistical narrow band correlated-K model with the updated model parameters was applied to calculate the gas transmissivity. The main intent of this paper is to compare the entropy generation components in two different configurations. The result shows that the entropy generation related to heat and mass transfer in the channel is higher than that estimated for the cylindrical annulus. Regarding optimal design selection, the entropy generation analysis, detailed in this paper, suggests a preference for the cylindrical annulus geometry. Our results may guide designers to select from the studied configuration. [ABSTRACT FROM AUTHOR]
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- 2023
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187. اثر خاکپوشهای زيستی بر مقاومت برشی کانالهای خاکی تحت شبیهسازی باران و فرسايش خاک.
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سید احمد حسینی, فرود شريفی, and محمدرضا غريبرضا
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Introduction Mechanical properties of most soils alter upon the increase of moisture and saturation. In some soils, certain phenomena appear due to increased moisture. Some of these phenomena lead to major damage in development projects. These soils are called Sensitive soils to water”. The most significant types of these soils are swelled soils, dispersive soils, and collapsible soils. Dispersive soils refer to clay soils that are easily washed up in waters with a low concentration of salt. Dispersion is a progressive phenomenon that starts from one point and is gradually extended. The start point of the dispersive phenomenon may refer to cracks resulting from shrinkage, soil deposition, or cracks made due to the roots of plants. This phenomenon is of great importance in such plans as soil dams and water supply channels where there is a water concentration inside the soil too. One of the essential reasons for soil erosion and sediment production in irrigation and drainage networks is the instability of canal soil, so it is necessary to use erosion control methods in parts of the canal route, especially at the intersection with other structures. To this end, the solution investigated and tested in this article is the use of biological mulches to reduce the erosion of the side slopes of earthen channels. Materials and Methods This research has been conducted on soil with a Loam sandy texture of irrigation and drainage channels network of the Arayez Plain of Khuzestan that lies on the west side of the Karkheh River. Using a simulated system, two-nozzle rainfall of the K18 feature was performed. To determine the effect of mulches on parameters of side wall erosive resistance of the soil structure, after the soil of the region passes through a sieve of 4.76 mm was put in the basin designed for 1 x 0.33 x 0.1 m for about 25 kg. After filtration, leveling, and pressing the soil to the edge of the Flume basin proportionate to the physical special weight of the soil, the stabilizing materials, and different bio mulches were sprayed in their different concentrations. Then, the basins inside the Flume with a side slope of 80% were put into a depth of 10 cm. In this research, with the objectives of determining the type and most appropriate level of biological mulches and their effect on the soil erosion resistance parameters of the lateral wall of the drainage channels of the Araiz plain of Khuzestan, the necessary experiments were conducted in the rain simulator laboratory of the Soil Conservation and Watershed Research Institute. So that using four types of water-based biological mulch, which were named with numbers 1 to 4 and at three levels of minimum (C1), medium (C2), and maximum (C3), experiments were conducted on the soil sample of the researched area. Each of the experimental treatments on a flume with a side slope of 1 to 1.25, similar to the side slope of canals in nature, was repeated and simulated three times in two rainfall intensities of 30 and 80 mm h-1. In each experiment, primary and secondary soil moisture, runoff volume, sediment weight, the intensity of water penetration in the treatments, and the shear strength of the treatments were measured. The experiments were conducted in a randomized complete block design in the form of split plots and the data were analyzed using SAS software and the averages were compared using the Student–Newman–Keuls (SNK) multi-domain test. Finally, by using mathematical models with optimization and minimization of sediment amounts and economic costs, the most suitable treatment for stabilizing the lateral walls of drains was determined. SPSS software was used for the statistical analysis of data and ANOVA and the Duncan test were used for the statistical comparison of data. Considering the tables obtained from data variance analysis and considering the statistic F and significance level, it can be said that all treatments are different in a significance level of 5% concerning the extent of sediment and there is a significant difference in the sediment amount. Results and Discussion The tests conducted on the soil of drainage channels of Arayez plain with a loamy – sand texture indicated that the presence of mulch coverage results in reduced sediment arising from rainfall in the manner that by the increase of density in any of the mulches, sedimentation reduces accordingly. The results obtained from the statistical analysis of this research confirmed that there is a significant difference in a level of 5% between sediment amounts of test control and mulch treatments for the sample of the soil under study. Therefore, bio mulches have an effective role in erosion control and the decrease of sediment from the walls of soil channels. The results indicated that only two types of biological mulches used in this study had a positive effect on shear resistance. General Linear Model (GLM) results showed that the interaction of two parameters of rainfall intensity with the type of treatment on shear strength is significant, so the interaction of rainfall intensity parameters with the level of materials used was not significant at the 5% level. In addition, the interaction of the type of treatment with the level of the materials used was also significant. According to the results of the analysis of variance in investigating the role of rainfall intensity on biological mulch treatments, it was found that rainfall intensity affected shear strength. Conclusion According to the above photos, all mulches compared to the control treatment have had a remarkable effect on the decrease of sediment. Moreover, it was found that the increase in the density of mulches used in all densities has had a remarkable effect on the decrease of outlet sediment. Furthermore, it was realized that the rainfall factor affects the increase of sediment. Thus, this effect in mulch 2 is the least effective in such a manner that upon increased rainfall in mulch 2m we see the minimum increase in the amount of sediment. The results after conducting system engineering and analyses related to the optimization of sediment amounts and economic costs indicated that mulch 2 at the C3 level has the best efficiency in increasing shear resistance. This conclusion could help the decision makers to allocate their soil conservation budget for the best performance activities. [ABSTRACT FROM AUTHOR]
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- 2023
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188. 水-力-热耦合作用下梯形渠道 断面尺寸优化组合.
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周蔚蔚 and 李 昂
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Copyright of Water Conservancy Science & Techonlogy & Economy is the property of Water Conservancy Science & Technology & Economy Editorial Office 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.)
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- 2023
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189. Closed-Form Capacity Reliability Analysis of Multiuser MIMO System in the Presence of Generalized Multipath Fading.
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Gvozdarev, Aleksey S., Alishchuk, Aleksandra M., and Kazakova, Marina A.
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MIMO systems , *NUMERICAL analysis , *ANTENNAS (Electronics) , *ERROR probability - Abstract
This research studies the problem of a joint capacity/capacity reliability analysis of the multiuser multi-input multioutput (MIMO) system functioning in the presence of generalized multipath fading. The study presents the derived results of the closed-form analytical statistical description of the ergodic sum-rate capacity, the capacity reliability and the capacity's higher-order statistics in the case of complex Nakagami-m distributed channel transmission coefficients. A numerical verification of the derived expressions was performed, and it demonstrated excellent correspondence with the simulation. The system performance was evaluated with the help of a numerical analysis of the joint first- and second-order statistics description, depending on the channel and system parameters. The results demonstrated several peculiarities, e.g., the existence of a specific extremum of the capacity reliability for small-sized MIMO systems, its opposite behavior (in terms of the varying number of antenna elements) for heavy and light fading, and the existing asymptotic regions of the system and the channel parameters. [ABSTRACT FROM AUTHOR]
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- 2023
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190. Dynamics of the translocation pore of the human peroxisomal protein import machinery.
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Ghosh, Mausumi, Denkert, Niels, Reuter, Maren, Klümper, Jessica, Reglinski, Katharina, Peschel, Rebecca, Schliebs, Wolfgang, Erdmann, Ralf, and Meinecke, Michael
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SIGNAL recognition particle receptor , *MEMBRANE proteins , *PROTEINS , *PEROXISOMES - Abstract
Peroxisomal matrix proteins are synthesized on cytosolic ribosomes and imported in a posttranslational manner. Intricate protein import machineries have evolved that catalyze the different stages of translocation. In humans, PEX5L was found to be an essential component of the peroxisomal translocon. PEX5L is the main receptor for substrate proteins carrying a peroxisomal targeting signal (PTS). Substrates are bound by soluble PEX5L in the cytosol after which the cargo-receptor complex is recruited to peroxisomal membranes. Here, PEX5L interacts with the docking protein PEX14 and becomes part of an integral membrane protein complex that facilitates substrate translocation into the peroxisomal lumen in a still unknown process. In this study, we show that PEX5L containing complexes purified from human peroxisomal membranes constitute water-filled pores when reconstituted into planar-lipid membranes. Channel characteristics were highly dynamic in terms of conductance states, selectivity and voltage- and substrate-sensitivity. Our results show that a PEX5L associated pore exists in human peroxisomes, which can be activated by receptor-cargo complexes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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191. Flume experiment study of the formation process and sedimentary characteristics of a shallow‐water delta.
- Author
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Chen, Cheng, Zhu, Yixiang, Lei, Zhengdong, Li, Shunming, and Jiang, Yun
- Subjects
- *
SEDIMENTATION & deposition , *FLUMES , *FLUVIAL geomorphology , *WATER levels , *WATER depth , *SUPPLY & demand , *SEDIMENTS , *SUBMARINE fans - Abstract
This paper investigates the influence of water level oscillation and sediment supply volume on shallow‐water delta development by means of a flume experiment. The experiment simulated the natural water level by dividing a cycle of sediment period into four parts: the draught period, the flood period (FP), the interflood period in a falling limb (IPF) and the interflood period in a rising limb (IPR). During the FP, flooding broke former channels and a large amount of sediments were evenly unloaded at the surface of lobes. Erosion often appeared at the beginning of the IPF and was dominant at low stand. Most sediments were concentrated in incised valleys and unloaded at the channel mouth to form a new lobe during the falling limb. Erosional channels and lobes were broken at the IPR. Sediments homogeneously covered the surface of lobes and few new lobes appeared during the period. Different sediment supplies influenced the characteristics of incised valley and channel style. Low sediment supply to the delta was strongly influenced by water level change, while high sediment supply was mainly affected by fluvial processes. Based on the flow sand content of water, channels can be classified into four types: (a) narrow and deep multiple channels, (b) narrow and shallow branch channels, (c) broad and shallow main channels, and (d) broad and deep stable channels. Their width‐to‐depth ratios are 1.1–3.5, 5.1–12.9, 7.3–20.2, 2.6–4.6, respectively. Most mouth bars were initially formed but then broken by water level oscillation and channel bifurcation. The preserved mouth bars were well preserved at the far end of lobes, where they entered the low‐energy environment. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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192. Structural Mechanics of Flexible Baffle Used in Enhancing Heat Transfer of Power Law Fluids in Channel-Trapezoidal Cavity.
- Author
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Yaseen, D. T. and Ismael, M. A.
- Subjects
- *
STRUCTURAL mechanics , *REYNOLDS stress , *HEAT transfer , *NON-Newtonian fluids , *POLITICAL succession , *PSEUDOPLASTIC fluids , *NATURAL heat convection , *CONVECTIVE flow - Abstract
Recent studies have proven the reliability of using flexible baffles in enhancing the rate of energy exchange in non-Newtonian fluids. The current study focuses on the deflection and the resulting stress in a baffle used in enhancing the heat transfer in an open trapezium filled with non-Newtonian fluid. The computational domain is a trapezoidal cavity opened to a parallel plate channel. A flexible baffle is hanged on the upper wall of the channel and its free end downwards towards the cavity center. The baffle interacts with the flow passing through the channel and also with the convective currents rising from the hot base of the cavity. The mathematical model is solved by ALE based on the finite element method. The study is performed by inspecting the roles of Reynolds number, the elasticity modulus of the baffle (governed by the Cauchy number) and the position of the baffle. The results showed that for shear thinning fluid the von Misses stress decreases with Reynolds number while for shear thickening fluid the trend is inverted. It is also found that the flexible baffle exhibits lower stress than the stiffer baffle, where at Re = 100, the von Misses stress is 518.5 and 642.7 at Ca = 10–4 and 10–5, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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193. Differences of Polygonal Faults with Irregularly Polygonal Geometries: A Case Study from the Changchang Sag of Qiongdongnan Basin, Northern South China Sea.
- Author
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Li, Yufeng, Pu, Renhai, Zhang, Gongcheng, and Fan, Xiaowei
- Abstract
Polygonal faults (PFs) generally have a classic polygonal geometry in map view. However, under the influence of tectonic faults, diapirs, channels, and slopes, the classic polygonal geometry of PFs is not preserved, demonstrating differences (different characters) in map-view 3D seismic data covering an area of 334 km
2 of the Changchang (CC) sag, are used to document the map-view and cross-sectional characteristics of PFs. These data also help investigate the irregularly polygonal geometries of PFs due to the presence of influence factors, such as transtensional faults, submarine fans, channels, diapirs/gas chimneys, and the basal slope within the lower-middle Miocene strata. Results show that various irregularly polygonal geometries of PFs can be classified into en-echelon and arcuate PFs, channel-segmenting and -bounding PFs, radial PFs, and rectangular PFs in map-view. En-echelon and arcuate PFs are induced by transtensional faults and exhibit a unique 'flower' structure in NE- and SE-trending cross-sections in the NW area of the study area. This finding is documented for the first time. Channel-segmenting PFs occur in the (northwest) low-amplitude muddy channel and are inhibited in the (southeast) high-amplitude sandy channel in the SW area. Radial PFs are radially aligned around a gas chimney/diapir containing some high-amplitude anomalies (HAAs) in the middle area. The presence of intrusive sandstones with HAAs along the periphery of the diapirs restricts the occurrence of PFs. Two high-amplitude submarine fans act as a mechanical barrier to the propagation of PFs. Meanwhile, the (moderate) slope in the NE area induces rectangular PFs. Additionally, the geneses of the PFs in the current study are comprehensively discussed. This study adds to our understanding of the differences between PFs with irregularly polygonal geometries. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
194. Downstream Controls on Coastal Plain River Avulsions: A Global Study.
- Author
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Colombera, Luca and Mountney, Nigel P.
- Subjects
COASTAL plains ,ALLUVIAL plains ,WATERSHEDS ,TSUNAMIS ,RIVER channels ,SUBMARINE fans - Abstract
The avulsion frequency of coastal‐plain rivers is primarily governed by the rate at which channels become superelevated over neighboring plains, which is itself controlled by multiple factors. Notably, the importance of wave and tidal processes, the rates of relative sea‐level (RSL) change, and the bathymetry of the receiving basin are thought to affect channel morphodynamics and channel‐mouth progradation, thereby controlling streambed aggradation and influencing the avulsion frequency and drainage density of coastal plains and deltas. This work tests the significance of these downstream factors on the avulsion histories of 57 Holocene lowland river systems. A quantitative analysis is performed of relationships between variables that quantify downstream controls and estimations of avulsion frequency, based on the number of avulsion events, active or abandoned channel paths, and delta lobes; measures of spatiotemporal avulsion "density" are also derived by normalizing these metrics by the size of study areas and the number of distinct drainage systems. Relationships between avulsion‐frequency metrics and descriptors of process regime indicate that wave and tidal processes may stabilize coastal channel systems, but also that their influence may be modest. No consistent relationship is seen between avulsion‐frequency proxies and the offshore bathymetric gradient, which in the studied examples does not scale with the rate of shoreline progradation. No evident trend exists between measures of avulsion frequency and estimated rates of either eustatic or RSL fluctuations. Overall, the considered variables do not leave a clear statistical signature in Holocene avulsion histories, suggesting that upstream or intrabasinal factors may represent more important controls. Plain Language Summary: Lowland rivers flowing near marine or lacustrine shorelines are affected by waves and tides, by relative variations in sea or lake level, and by the morphology of nearshore areas. These factors may affect the ability of coastal rivers to "avulse," that is, to establish new channel courses. This is expected because of how certain processes sculpt coastal landscapes: for example, waves may sweep sediment away from river mouths, tides can enhance sediment transfer along distributaries, and sea‐level rise or seaward advance of the shoreline can drive vertical shifts in the elevation of riverbeds. These factors can variably determine the degree to which coastal river channels may become raised above neighboring coastal areas, a situation that makes them prone to diversion to new paths following levee breaching. The significance of these supposed controls is evaluated through statistical analyses of the number of (a) channel diversions, (b) historical channel paths, and (c) landforms or sediment bodies representing increments of delta growth (delta lobes), as recognized in the millennial to centennial histories of 57 fluvial systems. Waves and tides may play a modest role in stabilizing coastal rivers, but the studied factors appear to exert a limited control on river diversions overall. Key Points: Holocene avulsion histories of 57 coastal plain river systems are analyzedRelationships between the intensity of wave and tides and river avulsion frequency are modestRiver avulsion frequency is not related to modern rates of absolute and relative sea‐level change [ABSTRACT FROM AUTHOR]
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- 2023
- Full Text
- View/download PDF
195. Computational analysis and expression profiling of potassium transport-related gene families in mango (Mangifera indica) indicate their role in stress response and fruit development.
- Author
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Lin Tan, Waqas, Muhammad, Rehman, Abdul, Rashid, Muhammad Abdul Rehman, Fiaz, Sajid, Manzoor, Hamid, and Azeem, Farrukh
- Subjects
FRUIT development ,GENE expression ,GENE families ,TROPICAL fruit ,DROUGHT tolerance ,COMPUTATIONAL neuroscience ,MANGO - Abstract
Mango (Mangifera indica) fruit is known for its taste, health benefits, and drought tolerance. Potassium (K
+ ) is one of the most abundant ions in a plant cell. It is important for various biological functions related to plant growth, development, and flowering/fruiting. It significantly contributes to fruit yield, quality, and drought tolerance in plants. However, molecular mechanisms comprising K+ transport in mango are least known. In the present study, 37 members of K+ transport-related genes (PTGs) were identified in mango, which include 22 K+ transporters (16 HAKs, 1 HKT, and 6 KEAs) and 15 K+ channels (6 TPKs and 8 Shakers). All PTGs were predicted to be expressed at the plasma membrane and possess characteristic motifs and domains. Phylogenetic analysis identified a strong kinship of PTGs among Oryza sativa, Arabidopsis thaliana, Cicer arietinum, Malus domestica, and M. indica. The promoter analysis identified 60 types of cis-elements related to various biological processes. RNA-seq-based expression profiling identified that MiTPK1.2, MiHAK1, MiHAK2.1, HAK6.1, and MiAKT1.1 were most upregulated in roots and that MiKEA2, MiAKT2, and MiAKT1 were upregulated in leaves. Moreover, MiAKT6, MiHAK1.1, MiKAT2, MiKAT2.1, MiHKT1, MiTPK1.1, MiHAK7, and MiHAK12 were highly expressed during the five growth stages of mango fruit. The current study is the first comprehensive report on K+ transport system in tropical fruits. Therefore, it will provide the foundation knowledge for the functional characterization of K+ genes in mango and related plants. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
196. Certain Exact Solutions to the Problem of Liquid Flow in Prismatic Tubes.
- Author
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Moshinskii, A. I.
- Subjects
- *
MECHANICS (Physics) , *REYNOLDS number , *CHANNEL flow , *LIQUIDS , *TUBES - Abstract
The problems of different sections of physics and mechanics share a mathematical model that is based on the Poisson equation with a constant right-hand side and a zero (constant) value of the sought function on the contour of a two-dimensional region. A set of exact solutions to the formulated problem is presented in the "plane" region of certain form to describe the following problems: flow of a liquid in the channel at small Reynolds numbers; motion of an ideal liquid during the rotation of the contour bounding the region; torsion of a rod; deflection of the membrane at the zero displacement on the boundary of the region; heating of the rod. The possibility to construct approximate solutions for certain cross sections of the channel, etc. by using these exact solutions is noted. Examples are given. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
197. Structural and mechanistic insights into the precise product synthesis by a bifunctional miltiradiene synthase.
- Author
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Tong, Yuru, Ma, Xiaoli, Hu, Tianyuan, Chen, Kang, Cui, Guanghong, Su, Ping, Xu, Haifeng, Gao, Wei, Jiang, Tao, and Huang, Luqi
- Subjects
- *
CRYSTAL structure , *FUNCTIONAL analysis , *DITERPENES , *AMINO acids , *MUTAGENESIS , *TRIPTOLIDE - Abstract
Summary: Selaginella moellendorffii miltiradiene synthase (SmMDS) is a unique bifunctional diterpene synthase (diTPS) that catalyses the successive cyclization of (E,E,E)‐geranylgeranyl diphosphate (GGPP) via (+)‐copalyl diphosphate (CPP) to miltiradiene, which is a crucial precursor of important medicinal compounds, such as triptolide, ecabet sodium and carnosol. Miltiradiene synthetic processes have been studied in monofunctional diTPSs, while the precise mechanism by which active site amino acids determine product simplicity and the experimental evidence for reaction intermediates remain elusive. In addition, how bifunctional diTPSs work compared to monofunctional enzymes is attractive for detailed research. Here, by mutagenesis studies of SmMDS, we confirmed that pimar‐15‐en‐8‐yl+ is an intermediate in miltiradiene synthesis. Moreover, we determined the apo‐state and the GGPP‐bound state crystal structures of SmMDS. By structure analysis and mutagenesis experiments, possible contributions of key residues both in class I and II active sites were suggested. Based on the structural and functional analyses, we confirmed the copal‐15‐yl+ intermediate and unveiled more details of the catalysis process in the SmMDS class I active site. Moreover, the structural and experimental results suggest an internal channel for (+)‐CPP produced in the class II active site moving towards the class I active site. Our research is a good example for intermediate identification of diTPSs and provides new insights into the product specificity determinants and intermediate transport, which should greatly facilitate the precise controlled synthesis of various diterpenes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
198. DISCOVERING WIRELESS NETWORKS VIA MODIFIED SCRIPTS IMPLEMENTING LINEAR ALGORITHMS FOR LINUX BASED OPERATING SYSTEMS.
- Author
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Boyanov, Petar Kr.
- Subjects
- *
LINUX operating systems , *SCRIPTS , *ALGORITHMS - Abstract
In this scientific paper modified scripts, implementing linear algorithms for discovering wireless networks in Linux based operating systems are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
199. Inhibition of transient receptor potential cation channel 6 promotes capillary arterialization during post‐ischaemic blood flow recovery.
- Author
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Numaga‐Tomita, Takuro, Shimauchi, Tsukasa, Kato, Yuri, Nishiyama, Kazuhiro, Nishimura, Akiyuki, Sakata, Kosuke, Inada, Hiroyuki, Kita, Satomi, Iwamoto, Takahiro, Nabekura, Junichi, Birnbaumer, Lutz, Mori, Yasuo, and Nishida, Motohiro
- Subjects
- *
TRP channels , *BLOOD flow , *HINDLIMB , *COLLATERAL circulation , *VASCULAR smooth muscle , *BLOOD circulation , *PERIPHERAL vascular diseases , *PERIPHERAL circulation - Abstract
Background and Purpose: Capillary arterialization, characterized by the coverage of pre‐existing or nascent capillary vessels with vascular smooth muscle cells (VSMCs), is critical for the development of collateral arterioles to improve post‐ischaemic blood flow. We previously demonstrated that the inhibition of transient receptor potential 6 subfamily C, member 6 (TRPC6) channels facilitate contractile differentiation of VSMCs under ischaemic stress. We here investigated whether TRPC6 inhibition promotes post‐ischaemic blood flow recovery through capillary arterialization in vivo. Experimental Approach: Mice were subjected to hindlimb ischaemia by ligating left femoral artery. The recovery rate of peripheral blood flow was calculated by the ratio of ischaemic left leg to non‐ischaemic right one. The number and diameter of blood vessels were analysed by immunohistochemistry. Expression and phosphorylation levels of TRPC6 proteins were determined by western blotting and immunohistochemistry. Key Results: Although the post‐ischaemic blood flow recovery is reportedly dependent on endothelium‐dependent relaxing factors, systemic TRPC6 deletion significantly promoted blood flow recovery under the condition that nitric oxide or prostacyclin production were inhibited, accompanying capillary arterialization. Cilostazol, a clinically approved drug for peripheral arterial disease, facilitates blood flow recovery by inactivating TRPC6 via phosphorylation at Thr69 in VSMCs. Furthermore, inhibition of TRPC6 channel activity by pyrazole‐2 (Pyr2; BTP2; YM‐58483) promoted post‐ischaemic blood flow recovery in Apolipoprotein E‐knockout mice. Conclusion and Implications: Suppression of TRPC6 channel activity in VSMCs could be a new strategy for the improvement of post‐ischaemic peripheral blood circulation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
200. Akvadukty v antickom Grécku (6.–2. storočie pred Kr.).
- Author
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Lindáková, Simona
- Subjects
WATER distribution ,TECHNOLOGY transfer ,AQUEDUCTS ,WATER supply - Abstract
Copyright of Studia Archaeologica Brunensia is the property of Masaryk University, Faculty of Arts 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.)
- Published
- 2023
- Full Text
- View/download PDF
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