Channel Profile Research Articles

Buckling analysis on various material profiles for truck chassis of ladder frame type

Chassis is the most important part of a truck, because it is closely related to the safety and weight of the truck. The profiles used for truck chassis differ as follows: C-channel, U-channel and rectangular tube. This study aims to reveal the most ideal profile for use as a truck chassis. The study was conducted using finite element analysis. The study conducted was buckling analysis. The variables observed for each test profile are free vibration, buckling safety factor, and deformation scale. the C channel profile is most ideal for use as a truck chassis. The simulation results show that the C channel profile has a buckling safety factor > 1 and the smallest average deformation occurs in each shape mode. The U channel profile has a light weight, but the deformation that occurs in each shape is greater than that of the C channel. The rectangular tube profile has the greatest safety factor in each shape mode, but has the largest deformation scale and weight.

Over-the-air testing for dual-polarized MIMO devices: Setup design and validation

Over-the-air (OTA) testing is considered as the only feasible solution to evaluate radio performances of the fifth-generation (5G) wireless devices which feature two important technologies, i.e., massive multiple-input multiple-output (MIMO) and millimeter-wave (mmWave). The multi-probe anechoic chamber (MPAC) based OTA setup is able to emulate realistic multipath propagation conditions in a controlled manner. This paper investigates an MPAC OTA setup which is capable of evaluating the performances of 5G base stations as the devices-under-test (DUTs) which are equipped with dual-polarized antennas. Both end-to-end setup and probe configuration for the considered MPAC setup will be elaborated. Furthermore, since building a practical MPAC setup is expensive, time-consuming, and error-prone, an end-to-end software testbed is established for validation purpose to avoid technical risks before finalizing an MPAC setup. The architecture of the testbed is presented, which can emulate both the channel profiles perceived by the DUT and the physical-layer behaviors of the considered link conforming to 5G new radio (NR) specifications. Results show that the performances under the emulated channel agree well with those under the target channel, validating the accuracy and effectiveness of the MPAC method.

Genetic Algorithm Based Model for Optimal Selection of Open Channel Design Parameters

Open channels are one of the most used water conveyance systems for delivering water for different purposes. Existing models for the design of open channels mainly assume uniform flow, focus on cross-section sizing, and generally decouple cross-section sizing from the selection of channel alignment and profile. In this study, we developed an optimization model for a comprehensive design of transmission channels. The model minimizes the sum of costs for earthwork, lining, water losses, and land acquisition; accounts for non-uniform, mixed-regime flow; and considers multiple geometric and hydraulic constraints. The model was validated using several idealized scenarios. The model potential in minimizing the cost of real open channel projects was demonstrated through application to an existing irrigation water transmission canal in Egypt (the Sheikh Zayed Canal). The results of validation scenarios matched the anticipated outcomes for channel profile and alignment and reproduced analytical solutions given in the literature for channel cross-section design. Application of the model to the Sheikh Zayed Canal gave a more optimal design; the OCCD model produced a design alternative with ~27% less cost than the constructed alternative.

Feedbacks between sea-floor spreading, trade winds and precipitation in the Southern Red Sea

Feedbacks between climatic and geological processes are highly controversial and testing them is a key challenge in Earth sciences. The Great Escarpment of the Arabian Red Sea margin has several features that make it a useful natural laboratory for studying the effect of surface processes on deep Earth. These include strong orographic rainfall, convex channel profiles versus concave swath profiles on the west side of the divide, morphological disequilibrium in fluvial channels, and systematic morphological changes from north to south that relate to depth changes of the central Red Sea. Here we show that these features are well interpreted with a cycle that initiated with the onset of spreading in the Red Sea and involves feedbacks between orographic precipitation, tectonic deformation, mid-ocean spreading and coastal magmatism. It appears that the feedback is enhanced by the moist easterly trade winds that initiated largely contemporaneously with sea floor spreading in the Red Sea.

Study of Two-Phase Microchannel Heat Sink Fabricated by A.M. Technology for Energy Reuse in the Electronic Device

Data centers’ electricity energy consumption accounts for 1% of global electricity demand and 0.3% of all global CO2 emissions. Energy reuse as a core of a net zero carbon data center, as a macro goal benefiting to mankind, needs micro innovations from thermal engineers to reclaim the distributed and low-grade thermal energy from diversified electronic equipment. This article presents the attempt to combine the advantages of high-density heat transferring technology by two-phase microchannels and the agility of Additive Manufacturing (A.M.) technology into a heat sink by which thermal energy can be collected in premium quantity and quality. The heat sink prototype adopted the two-layer microchannel design by leveraging the unique capability of A.M. technology to form complicated spatial geometric features, such as the functional channel profiles with diverged cross-sections along the flow direction, intermittent channels, and curved channels. It was fabricated at one-time processing by AlSi10Mg powder SLS/SLM, had an exterior base area of 25 cm2, and interior micro-fins with a minimal thickness of 0.2 mm and fin pitch of 0.38 mm. A test rig had been built to validate the thermal dynamic and hydraulic performance of this microchannel heat exchanger working with HFE 7100 as the coolant. The heat flux under certain wall superheat and pressure drop catches the equivalent grade of microchannels made by conventional micro-cutting approaches on copper or aluminum. The maximum inlet coolant temperature could be elevated up to 60.0 °C with less than 90.0 °C CPU case temperature, which provides the feasibility of high-grade heat recovery. The test results present the promising prospects of this design and A.M. technology in the field of two-phase microchannel heat exchanging, by which the electronic devices in megawatt hyperscale data center can be changed from energy consumers to energy generators for the greenhouse, district heating, and hot water system.

Use of high throughput ion channel profiling and statistical modeling to predict off-target arrhythmia risk - One pharma's experience and perspective

IntroductionThe use of high throughput patch clamp profiling to determine mixed ion channel-mediated arrhythmia risk was assessed using profiling data generated using proprietary internal and clinical reference compounds. We define the reproducibility of the platform and highlight inherent platform issues. The data generated was used to develop predictive models for cardiac arrhythmia risk, specifically Torsades de Pointes (TdP). MethodsA retrospective analysis was performed using profiling data generated over a 3-year period, including patch clamp data from hERG, Cav1.2, and Nav1.5 (peak/late), together with hERG binding. ResultsAssay reproducibility was robust over the 3-year period examined. High throughput hERG patch IC50 values correlated well with GLP-hERG data (Pearson = 0.87). A disconnect between hERG binding and patch was observed for ∼10% compounds and trended with passive cellular permeability. hERG and Cav1.2 potency did not correlate for proprietary compounds, with more potent hERG compounds showing selectivity versus Cav1.2. For clinical compounds where hERG and Cav1.2 activity was more balanced, an analysis of TdP risk versus hERG/Cav1.2 ratio demonstrated low TdP probability when the hERG/Cav1.2 potency ratios were < 1. Modeling of clinical compound data revealed a lack of impact of the Nav1.5 (late) current in predicting TdP. Moreover, models using hERG binding data (ROC AUC = 0.876) showed an improved ability to predict TdP risk versus hERG patch clamp (ROC AUC = 0.787). DiscussionThe data highlight the value of high throughput patch clamp data in the prediction of TdP risk, as well as some potential limitations with this approach.

In-situ and amplification-free imaging of hERG ion channels at single-cell level using a unique core-molecule-shell-secondary antibody SERS nanoprobe

Research on ion channels and their monoclonal antibodies plays a critical role in drug development and disease diagnosis. The current ion channel researches are often not conducted in the microenvironment for cells survival, which restricts the mechanism study of the links between the cell structure and the ion channel function. In this work, we synthesized gold core-4-mercaptobenzonitrile-sliver shell-goat anti-rabbit immunoglobulin G (Au@4-MBN@Ag@IgG) nanoparticles as surface-enhanced Raman scattering (SERS) nanoprobes for investigating the human ether-a-go-go related gene (hERG) potassium ion channel in cell membranes. This is the first attempt to study ion channels using SERS. Due to the unique core-molecule-shell structure and the silver shell of nanoprobes, strong and stable SERS signal was obtained. With the help of antibodies, the Au@4-MBN@Ag@IgG nanoprobes were captured by hERG antibodies and then bonded with hERG ion channels based on the sandwich immune response. The reporter molecule, 4-MBN, displayed a strong and sharp characteristic peak at 2233 cm-1 in the Raman silent region. The intensity of this peak denoted the concentration of antibodies and the expression of ion channel proteins. We successfully applied this amplification-free method for in-situ imaging the distribution of the hERG ion channel on the transfected HEK293 cell surface at the single-cell level. This hERG ion channel profiling strategy promises a maneuverable tool for ion channel research.

Modeling of velocity and shear stress profiles in the ecological channel with floating vegetation.

Floating vegetation occurs in various environments, such as artificial floating islands, wetlands, river courses, and lakes, which constitute an important part of the river landscape and ecological restoration. The vertical distribution of the streamwise velocity of the channel flow with floating vegetation is of the utmost importance, and therefore, it is the basis for research on bed erosion and pollutant transport. Laboratory experiments on an open-channel flow covered by floating vegetation with unanchored roots have shown a two-layer structure of the velocity profile and a rapid decrease in the Reynolds stress across the interface in the vegetation layer but gradual in the non-vegetation layer. The flow was divided into four subzones in a vertical direction according to the organized flow structure in the experiment as follows: (I) the uniform region deep within the non-vegetation layer, (II) the outer region in the non-vegetation layer, (III) the inner region in the vegetation layer, and (IV) the uniform region deep within the vegetation layer. An analytical model based on the momentum balance in each subzone was developed to predict the profiles of velocity and Reynolds stress. The predictions from analytical models agree well with those from laboratory studies of floating vegetation and lay the theoretical foundation for future studies on water eutrophication and the transport of pollutants, sediments, and algae.

New interaction formula for plastic resistance of channel sections under combinations of bending moments My,Ed, Mz,Ed and bimoment BEd

The interaction formulae for the plastic resistance of channel sections under combination of 4 internal forces: the bending moment about strong axis My,Ed, the bending moment about weak axis Mz,Ed, the bimoment BEd and the axial force NEd were created and analyzed. The exact interaction curves obtained by the linear programming for 4 internal forces have enabled to create and to verify the proposed approximate interaction formula for 3 internal forces.The approximate interaction formula for the design plastic resistance of channel sections under combination of 3 internal forces: the bending moment about strong axis My,Ed, the bending moment about weak axis Mz,Ed and the bimoment BEd was analyzed and verified. The explicit interaction formula that takes into account these 3 internal forces is missing in Eurocodes. A large parametrical study was performed for the rolled channel profiles within the size range UPE 80 UPE 400. The differences between the results of the approximate interaction formula and the exact interaction curves were analyzed and summarized.Till today nobody presented results of the parametrical study of the channel sections under the combination of 4 internal forces.

Insight on the regulation mechanism of the nanochannels in hard and brittle materials induced by sparially shaped femtosecond laser.

The efficient fabrication of nanochannels on hard and brittle materials is a difficult task in the field of micro and nano processing. We have realized nanochannel arrays on silica with characteristic scales varying from 50–230 nm using a single femtosecond Bessel beam pulse of 515 nm. By characterizing the surface openings, we found that the characteristic scales of the nanopore openings are inextricably linked to the surface energy deposition effect. We achieved not only three asymmetric channel profiles by adjusting the laser-sample interaction region, but also high aspect ratio nanochannels with characteristic scales about 50 nm and aspect ratios over 100. These results on hard and brittle materials provide a broader platform and application scenarios for smart particle rectifiers, DNA molecular sequencing, biosensors, and nanofluidic devices, which are also more suitable for future practical applications due to their low cost, good durability, and high productivity.

Improvement of the subcooled boiling model using a new net vapor generation correlation inferred from artificial neural networks to predict the void fraction profiles in the vertical channel

In the one-dimensional thermal-hydraulic (TH) codes, a subcooled boiling model to predict the void fraction profiles in a vertical channel consists of wall heat flux partitioning, the vapor condensation rate, the bubbly-to-slug flow transition criterion, and drift-flux models. Model performance has been investigated in detail, and necessary refinements have been incorporated into the Safety and Performance Analysis Code (SPACE) developed by the Korean nuclear industry for the safety analysis of pressurized water reactors (PWRs). The necessary refinements to models related to pumping factor, net vapor generation (NVG), vapor condensation, and drift-flux velocity were investigated in this study. In particular, a new NVG empirical correlation was also developed using artificial neural network (ANN) techniques. Simulations of a series of subcooled flow boiling experiments at pressures ranging from 1 to 149.9 bar were performed with the refined SPACE code, and reasonable agreement with the experimental data for the void fraction in the vertical channel was obtained. From the root-mean-square (RMS) error analysis for the predicted void fraction in the subcooled boiling region, the results with the refined SPACE code produce the best predictions for the entire pressure range compared to those using the original SPACE and RELAP5 codes.

Post-Transition-State Direct Dynamics Simulations on the Ozonolysis of Catechol.

On-the-fly dynamics simulations are performed for the reaction of catechol + O3. The post transition state (TS) dynamics is studied at temperatures of 400 and 500 K. The PM7 semiempirical method is employed for calculating the potential energy gradient needed for integrating Hamilton's equations of motion. This semiempirical method provides excellent agreement in terms of energy and geometry of the TSs as well as minimum energy states of the system with respect to B3LYP/6-311+G (2df, 2p) calculated results. In the dynamics, first, a peroxyacid is formed, which further dissociates to different fragments. Four major channels forming CO, CO2, H2O, and small carboxylic acid (SCA) fragments are seen in this reaction. Rates of each of the channels and the overall unimolecular reaction are calculated at both temperatures. Branching ratios of all these product channels are calculated and compared with experiment. The minimum energy profile of CO2, CO, and H2O channels are calculated. A qualitative estimate of activation energies for all the channels are obtained and compared with the explicit TS energies of three product channels, which ultimately correlate with the reaction probabilities.

Long-term investigation of morphodynamic variations of a tidal inlet by remote sensing: A case study of the Meidani Inlet, Hormozgan, Iran

Barrier-island inlets are among the most common inlets worldwide. The variation of the inlets, different sediment bypassing mechanisms, and lack of data are some issues for using numerical modeling in all cases. Remote sensing techniques are helpful for analytical investigation and making time series of the study area for categorizing the inlets and defining the morphological processes. The current study employs a feasible method for investigating tidal inlets, evaluates the morphodynamic changes, and applies the method to the Meidani Inlet in Iran. In this study, Landsat images from 1972 to 2019 were acquired and corrected to investigate changes in the ebb-tidal delta by employing the shoreline determination method, performing bathymetry in shallow areas, evaluating the extracted profiles in specific locations within the ebb-tidal delta, and comparing the Landsat image series at various times (change detection). In order to illustrate the morphological changes during the study period, a conceptual model was proposed. The conceptual model presents three reiterated actions of the ebb-tidal delta that varied from 15–25 years due to different environmental conditions. Regional waves, tidal, and wind data were analyzed in detail using Landsat image intervals to investigate the effects of factors causing changes and instability in the cyclic morphodynamic behavior of the Meidani Inlet and characterize the region’s environmental behavior pattern. By employing the method mentioned above, preparing a temporal inlet channel profile and sedimentation trend in the ebb-tidal delta, the Meidani Inlet is determined to be a mixed-energy inlet and a possibility of long-term behavior is predicted. Eastward main inlet channel and the whole ebb-tidal delta migration is the strongest possibility based on the remote sensing investigation over the investigated period.

An Effective Generative Model Based Channel Estimation Method With Reduced Overhead

The traditional channel estimation for OFDM systems suffers from big overheads caused by pilots. Current channel estimation methods only consider the correlation among pilots within a time-frequency grid, which is a kind of local channel information. In this article, we propose a Generative Adversarial Network (GAN) based channel estimation method to utilize not only local channel information but also correlation across multiple frames, thus much fewer pilots are needed. We propose to explore GAN to establish a mapping from a low dimensional space to a high dimensional channel space. Then based on very few pilots, we solve an optimization problem to localize the low dimensional vector corresponding to the specified channel and generate the corresponding channel. Furthermore, we propose an improved conditional GAN (cGAN), which takes the multi-path number as conditional information, making the proposed generative channel model more robust in various scenarios. Experiments demonstrate that the proposed cGAN-based method can be applied to multiple channel profiles once trained offline, and it is robust to the mismatch of multi-path number. Besides, the proposed method outperforms the ideal ALMMSE and ChannelNet methods under the same pilot density. In the best case, it can achieve comparable performance with only about half the number of pilots.

Adaptive design methodology of segmented non-uniform fin arrangements for trans-critical natural gas in the printed circuit heat exchanger

As the core heat transfer equipment of a floating storage regasification unit (FSRU), the printed circuit plate heat exchanger (PCHE) has a significant impact on the gasification performance of liquefied natural gas (LNG). During LNG regasification process, natural gas undergoes a trans-critical process and its thermal properties such as density, viscosity and specific heat capacity vary considerably especially near the pseudo-critical point, which will probably lead to more volatile flow heat transfer mechanism. The traditional design scheme of uniform finned channel is difficult to give full play to the efficiency and compactness of PCHE because of lacking considering the local fluid thermodynamic variation. Therefore, this paper provides a novel design method for optimizing the flow channel profile of PCHE by applying adaptive segmented non-uniform finned micro-channels. Firstly, the entire flow channels are segmented by qualifying the gradient of density with temperature ∂ρ/∂t of trans-critical natural gas. Subsequently, within the constraints of heat exchange requirements, maximum allowable pressure drop, existing manufacturing techniques and structural strength, a mathematical optimization design model considering non-uniform fin arrangements and interlinked thermal states among these segmented channels is established. Then, to comprehensively improve entropy generation number and volume, Pareto solutions covering local flow channel parameters are obtained based on multi-objective genetic algorithm. Finally, the actual performance differences between two optimization methods respectively derived from the conventional uniform fin channels and the proposed non-uniform fin arrangements are compared based on distributed parameter model. The results show that the deviation of the entropy generation number between the optimized and validated values for the non-uniform design is very small at 6.5%, much less than that of 31.4% in the uniform design. Moreover, under the premise of the similar heat transfer efficiency, the volume for the PCHE by the non-uniform design can be reduced by 9.3%. These indicate that the proposed design methodology of segmented non-uniform fin arrangements indeed makes the PCHE more compact and enables the thermal-hydraulic performance better. The current work will serve as a framework for the design and optimization of PCHEs with drastic changes in fluid physical properties.

Analysis of interferometric configuration for optical devices

Abstract With the exponential growth in information related applications and the continuous increase in voice over IP (VoIP) applications, the carriers are expanding their networks to provide improved services to their end users. In such cases, the synchronous optical network/synchronous digital hierarchy model is not suitable. In this work, we are going to investigate the electro optic switch with the help of a VB script to simulate the device for various parameters. Further, we will then scan the central electrode voltages and take account of the overlap integral taking place at the output port with the help of waveguide mode. The best switching for switches at different voltages so as to have negligible coupling loss for different input signals is investigated. We aim to evaluate the MZI switches with the Li-Tn channel profile wave guiding structure and confirm their performance as compared to the existing MZI switches.

Hydromorphological Characterization of the Piney Creek Watershed of Raleigh County, West Virginia, a Tributary of the New River Gorge National Park

In this investigation information was collected regarding the habitat condition, channel profile, and stream discharge of key waterways within the Piney Creek Watershed in vicinity of Beckley, Raleigh County, West Virginia. Piney Creek is a major tributary that flows into the New River within the New River Gorge National Park and Preserve. To establish robust and sustainable ongoing stream monitoring, West Virginia University Institute of Technology (WVU Tech), Beckley Sanitary Board (BSB) and Piney Creek Watershed Association (PCWA) partnered in conducting stream habitat assessments at key sites within the watershed utilizing the guidelines provided by the West Virginia Department of Environmental Protection’s Save Our Streams initiative. Additionally, the organizations developed standard operating procedures for calculating flow and discharge utilizing low-cost, easy-to-perform float gauging methodology. In total, 21 sites from five named streams (Beaver Creek, Cranberry Creek, Little Whitestick Creek, Whitestick Creek, and Piney Creek) and seven unnamed streams were selected and assessed for channel width and depth, velocity, discharge, sediment deposition, embeddedness, bank stability, riparian buffer, and stream bed composition. Streambed composition and discharge showed variability among the subwatershed sites. Nine site habitat scores received overall habitat scores of “suboptimal”, while ten were scored as “marginal” and two as “poor” stream habitat. Lack of riparian buffer was found to be the most frequent habitat score deficiency in the Piney Creek Watershed, with 18 out of the 42 total stream banks receiving a score of “poor” in this category. Characterization of the watershed is important for establishing baseline information as well as identifying important sites for future research and execution of improvement projects. This study defines an area that could serve as an accessible research resource and model watershed.

Heat flow through a liquid–vapor interface in a nano-channel: the effect of end-grafting polymers on a wall

Heat transfer through a liquid–vapor interface is a complex phenomenon and crucially relevant in heat-removal and cryogenic applications. The physical coupling among confining walls, liquid and vapor phases is very important for controlling or improving cooling rates or condensation efficiency. Surface modification is a promising route, which has been explored to taylor the heat transfer through confined two-phase systems. We use coarse-grained molecular-dynamics simulations to study the heat transfer through a nano-confined liquid–vapor interface as a function of fluid filling. We set up a stationary heat flow through a liquid–vapor interface, stabilized with the liquid in contact with a colder wall and a vapor in contact with a hotter wall. For these physical conditions, we perform extensive simulations by progressively increasing the number of fluid particles, i.e. the channel filling, and measure the fluid distribution in the channel, density, pressure and temperature profiles We also compare the heat flux behavior between a bare-surfaces nano-channel and others where the hot surface was coated with end-grafted polymers, with different wetting affinities and bending properties. We take extreme cases of polymer properties to obtain a general picture of the polymer effect on the heat transfer, as compared with the bare surfaces. We find that walls covered by end-grafted solvophylic polymers change the heat flux by a factor of 6, as compared with bare walls, if the liquid phase is in contact with the polymers. Once the liquid wets the coated wall, the improve on heat flux is smaller and dominated by the grafting density. We also find that for a wall coated with stiff polymers, the jump in heat flux takes place at a significantly lower channel filling, when the polymers’ free ends interact with the liquid surface. Interestingly, the morphology of the polymers induces a ‘liquid bridge’ between the liquid phase and the hot wall, through which heat is transported with high (liquid-like) thermal conductivity.

Effect of rigid, bank vegetation on velocity distribution and water surface profile in open channel

Abstract The effects of rigid ditch bank vegetation on velocity distribution and water surface profile in trapezoidal open channels were investigated. Forty-eight tests were used to study the impacts of different vegetation densities. Tests were run for three vegetation densities (1,600, 400, and 178 stems/m2) along a fixed, 4.00 m reach, against four different discharges, each with three different depths. The measured water levels and velocities were analyzed and it was found that increasing the vegetation density increased the water depth upstream of the vegetated reach. while lowering it within it, when compared to the unvegetated case. The water's velocity profile as a ratio to the unvegetated case (V/u) is sigmoid, i.e., the maximum velocity (V/u) max occurs in the lower half of the water column, increasing shear stress near the bed, and, in turn, the likelihood of bed erosion along the vegetated channel's centerline. V/u increased with increasing vegetation density and Fro. A multiple regression analysis was done to assess the impact of ditch bank vegetation density on flow parameters.

The Effect of Flow Channel Geometry on Thermomechanical Performance of Printed Circuit Heat Exchanger (PCHE)

Abstract The carbon-free energy systems such as nuclear can benefit from compact and highly efficient heat exchanger technologies. The plate-type compact heat exchangers such as the printed circuit heat exchanger (PCHE) holds promise to fulfill these requirements. This work presents the thermal-hydraulic and structural analysis of PCHE for molten salt applications with thermal energy storage. In this study, three distinct types of geometry are chosen for the analysis, i.e., the zigzag channel type, the airfoil fin type, and the slotted fin type. For the working fluid, FLiBe (Li2BeF4) and solar salt (60% NaNO3 and 40% KNO3) are chosen for hot side and cold side, respectively. Titanium grade 5 is chosen as the structural material. The study is conducted by computational fluid dynamics (CFD) and finite element method (FEM) analysis. The thermomechanical behavior including pressure drop, fluid temperature, velocity profile, stress, and deformation of the flow channel were considered in this work. From the results, the zigzag channel geometry gives the best thermal hydraulic performance in terms of heat transfer and pressure drop. The structural analysis shows that the stress intensity has an exponential growth with power generation level with zigzag channel geometry being the highest out of three geometries. Overall, the zigzag channel PCHE is still the most suitable geometry for this application. Zigzag channel geometry should be substituted with an alternative geometry at a high-power application having both airfoil-fin and slotted-fin geometry at relatively identical stress intensity.