Flow Profile Research Articles

Spatter transport in a laser powder-bed fusion build chamber

The adverse effects of spatter particles are well known in laser powder-bed fusion (LPBF) additive manufacturing. To prevent the deposition of spatter particles, an inert gas flow is commonly used to transport these spatters away from the build plate. However, the inert gas flow does not remove all spatters due to varying spatter sizes and ejection angles. Therefore, it is essential to understand and predict spatter trajectories to achieve superior LPBF parts. The present study focuses on numerical modelling of spatter trajectories in Renishaw AM250 using an Eulerian-Lagrangian discrete phase model. The argon velocity profile and spatter trajectories with and against the flow are computed for various materials, sizes and ejection angles. The simulation results are validated with experimental results and show a presence of uneven flow due to inlet geometry along with varying flow profiles across the build height due to inlet location. Spatter analysis shows three methods which result in spatter deposition. Spatter particles either fall directly on the build plate, are transported by the airflow or are re-directed in the recirculation zone. The findings presented in this work indicate the importance of build chamber design along with material-based parameter optimization that results in maximum spatter removal.

Prognostic Implications of Resistive Reserve Ratio in Patients With Nonobstructive Coronary Artery Disease With Myocardial Bridging.

Myocardial bridging (MB) is accompanied by the dynamic extravascular compression of epicardial coronary arteries, leading to intracoronary hemodynamic disturbance with abnormal coronary flow profiles. We aimed to evaluate the prognostic implications of resistive reserve ratio (RRR), a composite measure of flow and pressure parameters that represents the vasodilatory capacity of the coronary arteries, in patients with angina with nonobstructive coronary artery disease (ANOCA) and MB, in comparison with coronary flow reserve (CFR). In this retrospective cohort study, we included patients with ANOCA who underwent coronary reactivity testing, where MB was identified by transient constriction in coronary artery segments between systole and diastole. Abnormal CFR and RRR were defined as <2.5 and <2.62, respectively. Major adverse cardiac events, including cardiovascular death, stroke, myocardial infarction, heart failure, and late revascularization, served as outcomes. Among 1251 patients with ANOCA, 191 (15.3%) had MB. The prevalence of abnormal CFR or RRR was not significantly different between patients with and without MB (P=0.144 and P=0.398, respectively). Over a median follow-up time of 6.9 years, abnormal RRR predicted major adverse cardiac events in patients with MB (hazard ratio [HR], 4.38 [95% CI, 1.71-11.21]; P=0.002) and without MB (HR, 1.91 [95% CI, 1.38-2.64]; P<0.001). Abnormal CFR predicted major adverse cardiac events in patients without MB (HR, 2.15 [95% CI, 1.54-3.00]; P<0.001), whereas it was not predictive of major adverse cardiac events in patients with MB (HR, 2.29 [95% CI, 0.93-5.65]; P=0.073). In patients with ANOCA and MB, impaired RRR was superior to impaired CFR in distinguishing patients at a higher risk of future adverse events, suggesting that RRR may serve as a risk stratification tool in patients with MB and ANOCA.

Impacts of thermally stratified medium on transient convective heat transfer between co‐axial horizontal fixed pipes: Applications of the thermal stratification

AbstractThermal stratification improves coaxial pipe systems’ efficiency and stability. Thermal stratification enables accurate temperature maintenance, reduces thermal stress, optimizes heat transmission performance, and minimizes usage of energy to guarantee the system's long‐term performance. The main aim of the current study is to investigate the impacts of thermal stratification on buoyancy force flow and thermal transmission between coaxial fixed pipes. In the present research, the applications of thermally stratified medium on transient convective heat transfer between two coaxial fixed pipes are studied. A two‐dimensional mathematical formulation in terms of mutually nonlinear partial differential equations is used to analyze the unsteady flow and temperature field between the co‐axial pipes, when the internal pipe is uniformly heated and the outer wall of the external pipe is placed at infinity from the surface of the inner fixed pipe. Flow is assumed along the axial direction of the internal pipe and stationary boundary condition is assumed at the surface of the inner pipe. The coupled equations of the simulated model are solved numerically by applying the Implicit Finite Difference Technique. The computed outcomes in the form of geometrical interpretation are highlighted by using the technically advanced software TECHPLOT‐360. Comprehensive detail of the obtained results for the non‐dimensional parameters included in the flow formulation is predicted for steady state velocity, temperature distribution, time‐dependent surface shearness and time‐dependent energy shearness in results and discussion section of the manuscript. The emphasis is placed on the thermal stratification parameter in the above mentioned chief quantities. From the obtained results, it is predicted that the fluid flow pattern and thermal distribution are both reduced for rising values of the thermal stratification parameter S = 0.001, 0.03, 0.05, and 0.07. Minimum flow and thermal profile are observed at S = 0.07. Further, the amplitude of the time‐dependent surface shearness is uniformly distributed throughout the medium and the amplitude of the time‐dependent energy shearness is reduced effectively for S = 1.0, 5.0, and 10.0.

On the feasibility of ultrasound Doppler-based personalized hemodynamic modeling of the abdominal aorta

BackgroundPersonalized modeling is a promising tool to improve abdominal aortic aneurysm (AAA) rupture risk assessment. Computed tomography (CT) and quantitative flow (Q-flow) magnetic resonance imaging (MRI) are widely regarded as the gold standard for acquiring patient-specific geometry and velocity profiles, respectively. However, their frequent utilization is hindered by various drawbacks. Ultrasound is used extensively in current clinical practice and offers a safe, rapid and cost-effective method to acquire patient-specific geometries and velocity profiles. This study aims to extract and validate patient-specific velocity profiles from Doppler ultrasound and to examine the impact of the velocity profiles on computed hemodynamics.MethodsPulsed-wave Doppler (PWD) and color Doppler (CD) data were successfully obtained for six volunteers and seven patients and employed to extract the flow pulse and velocity profile over the cross-section, respectively. The US flow pulses and velocity profiles as well as generic Womersley profiles were compared to the MRI velocities and flows. Additionally, CFD simulations were performed to examine the combined impact of the velocity profile and flow pulse.ResultsLarge discrepancies were found between the US and MRI velocity profiles over the cross-sections, with differences for US in the same range as for the Womersley profile. Differences in flow pulses revealed that US generally performs best in terms of maximum flow, forward flow and ratios between forward and backward flow, whereas it often overestimates the backward flow. Both spatial patterns and magnitude of the computed hemodynamics were considerably affected by the prescribed velocity boundary conditions. Larger errors and smaller differences between the US and generic CFD cases were observed for patients compared to volunteers.ConclusionThese results show that it is feasible to acquire the patient-specific flow pulse from PWD data, provided that the PWD acquisition could be performed proximal to the aneurysm region, and resulted in a triphasic flow pattern. However, obtaining the patient-specific velocity profile over the cross-section using CD data is not reliable. For the volunteers, utilizing the US flow profile instead of the generic flow profile generally resulted in improved performance, whereas this was the case in more than half of the cases for the patients.

Characterisation of biocondensate microfluidic flow using array-detector FCS

BackgroundBiomolecular condensation via liquid-liquid phase separation (LLPS) is crucial for orchestrating cellular activities temporospatially. Although the rheological heterogeneity of biocondensates and the structural dynamics of their constituents carry critical functional information, methods to quantitatively study biocondensates are lacking. Single-molecule fluorescence research can offer insights into biocondensation mechanisms. Unfortunately, as dense condensates tend to sink inside their dilute aqueous surroundings, studying their properties via methods relying on Brownian diffusion may fail. MethodsWe take a first step towards single-molecule research on condensates of Tau protein under flow in a microfluidic channel of an in-house developed microfluidic chip. Fluorescence correlation spectroscopy (FCS), a well-known technique to collect molecular characteristics within a sample, was employed with a newly commercialised technology, where FCS is performed on an array detector (AD-FCS), providing detailed diffusion and flow information. ResultsThe AD-FCS technology allowed characterising our microfluidic chip, revealing 3D flow profiles. Subsequently, AD-FCS allowed mapping the flow of Tau condensates while measuring their burst durations through the stationary laser. Lastly, AD-FCS allowed obtaining flow velocity and burst duration data, the latter of which was used to estimate the condensate size distribution within LLPS samples. ConclusionStudying biocondensates under flow through AD-FCS is promising for single-molecule experiments. In addition, AD-FCS shows its ability to estimate the size distribution in condensate samples in a convenient manner, prompting a new way of investigating biocondensate phase diagrams. General significanceWe show that AD-FCS is a valuable tool for advancing research on understanding and characterising LLPS properties of biocondensates.

Flow Through a Passage With Scaled Additive Manufacturing Roughness Representing Different Printing Orientations

Abstract Components with internal passages created using some laser-sintering based, additive manufacturing (AM) systems can exhibit anisotropic surface features with an appearance of three-dimensional roughness superimposed on two-dimensional, rib-like features. This paper presents an investigation of flow over roughness representing internal cooling passages printed at different angles to the AM printing plane. A roughness geometry was acquired using an X-ray tomography scan of a direct-metal-laser-sintering (DMLS) created coupon with internal cooling passages. The base surface scan was then used to create four surfaces with notional rib-like features positioned at different angles relative to the spanwise flow direction. The flow resistance of each surface was measured using the roughness internal flow tunnel. The mean flow velocity profiles for the cases with ReDh ≤ 30,000 were characterized using a four-camera, tomographic, and particle tracking system. The results demonstrate roughness orientation effects include (1) reduced bulk flow resistance as the alignment angle from the spanwise direction increases, (2) generated flow in the spanwise direction and increased tunnel flow swirl as the alignment angle increases, and (3) velocity profile changes as the flow migrates away from the rough side of the tunnel to the opposing smooth wall. The particle tracking system also demonstrates that the mean streamwise flow profiles change significantly between the 30 deg and 45 deg roughness orientations. Finally, the equivalent sandgrain roughness measurements for the four surfaces were found to follow the trends predicted using the correlations of Bons (2002, “St and cf Augmentation for Real Turbine Roughness With Elevated Freestream Turbulence,” ASME J. Turbomach., 124(4), pp. 632–644.) and Sigal and Danberg (1990, “New Correlation of Roughness Density Effect on the Turbulent Boundary Layer,” AIAA J., 28(3), pp. 554–556.).

Application Of Particle Image Velocimetry For The Anatomical Comparison Of Haemodynamics In Healthy And Treated Aortas.

The leading cause of mortality and morbidity globally is cardiovascular disease (CVD). CVD can present in the thoracic aorta as atherosclerosis, an aneurysm or a dissection, which can be related to certain fluid mechanics metrics. This study investigates the fluid flow profiles within a healthy and a branched endovascular graft-treated rigid phantom, manufactured from Sylgard 184, to determine the effect geometry has on the resulting fluid mechanics and the subsequent biological processes. Planar particle image velocimetry data was recorded to visualise steady flow conditions at Reynolds numbers 4500 (peak), 3400 (mean), and −225 (reverse). Evaluation of anatomical features affecting the flow fields, concluded that the tapering of the healthy thoracic aorta naturally aids in the prevention of low flow on the inner arch wall more effectively than the untapered graft-treated model. Focus on the aortic branches demonstrated the angle of the aortic branches in relation to the aortic arch, highly affects the regions of low and high blood flow present within each branch. However, due to the biological response (or lack of) associated with a cellular boundary and synthetic material, the haemodynamic changes in the aortic arch and branches have different challenges. Therefore, direct replication of a healthy geometry is not necessarily optimal for the design of an endovascular graft.

Extension Of Spatial Filtering Technique Using Kalman Filters For Real-Time Pipe Flow Profile Measurements

Spatial filtering is used for real-time velocity measurement due to its computational efficiency. However, this method can be noisy in real measurement environments, requiring the averaging of a substantial number of measurements to achieve reliable results, which compromises temporal resolution. This study proposes enhancing the spatial filtering algorithm by implementing Kalman filtering for pipe flow profile measurements. Kalman filtering is expected to mitigate the noise issue more effectively than traditional methods like low-pass filtering while maintaining or improving the temporal resolution of measurements.

Dynamics and spectral character of unsteady pressure field on afterbody of generic space launcher: Transonic flows

The unsteady pressure field over an axisymmetric backward-facing step was investigated experimentally at transonic freestream Mach numbers of 1.05, 1.2, and 1.4. The study was aimed at examining the influence of transonic freestream Mach numbers on the spatio-temporal character of the unsteady pressure field and on the dominant modes/mechanisms driving it. Surface flow visualization, schlieren, and unsteady pressure measurements were carried out as part of the experimental investigation. From oil flow visualization and schlieren, the reattachment region was identified, and consequently, the mean reattachment length was estimated. The mean reattachment length shows an increase with the increase in freestream Mach number. The coefficient of mean pressure along the rearbody imitates a classical backward-facing step flow profile and can be divided into three distinct regions. The peak values of the coefficient of mean pressure and the coefficient of root mean square of the fluctuation are seen to decrease with an increase in the freestream Mach number. Conventional spectral analysis reveals that as the freestream Mach number increases, the dominant peak in the spectra shifts to lower frequencies. From the spectra, three dominant fluid dynamic mechanisms depending on the freestream Mach number have been identified. Proper Orthogonal Decomposition (POD) analysis shows that 79–84 % of the total energy contribution comes from the first six modes. The temporal dynamics of the POD modes indicate three prominent mechanisms are responsible for the unsteady pressure field. Spectral analysis of POD modes indicates that the spectra are primarily driven by the first three POD modes for freestream Mach number of 1.05 and the first two modes for freestream Mach numbers of 1.2 and 1.4. Moreover, it reveals the presence of three dominant modes, and the freestream Mach number strongly dictates the dominant mode that is driving the pressure field.

Hydrodynamics in a randomly packed bed of cylindrical particles: A comparison between PR-CFD simulations and MRI experiments

Slender catalytic packed bed reactors are widely used in the chemical industry for chemical processes accompanied with significant heat liberation necessitating efficient heat removal. The employed catalyst particles are often cylindrical shaped, because these are easily manufactured via extrusion. The packing of these cylindrical particles results in a random structure of the bed causing flow maldistribution which reduces the reactor efficiency. The goal of this work is to capture the flow maldistribution with particle-resolved Computational Fluid Dynamics simulations and Magnetic Resonance Imaging experiments. By utilising the packing configuration reconstructed from the experiments, we are able to study the average fluid flow profiles and flow distribution in the bed as well as the local velocity profiles. It can be concluded that there is an overall good correspondence between the experiments and simulations. The minor deviations in the experimental and computed velocity distributions can be attributed to experimental error and slight differences in the experimental and reconstructed packing.

Non-Similar Analysis of Mixed Convection Biomagnetic Boundary Layer Flow Over a Vertical Plate with Magnetization and Localized Heating/Cooling

Theoretical and numerical investigation of an applied magnetic field on mixed convection flow of a biofluid through a vertical plate using contained heating or cooling is observed in this study. The mathematical formulation is that of the full Biomagnetic Fluid Dynamics (BFD) model which deals with on the ferrohydrodynamics (FHD) and magnetohydrodynamics (MHD) principle. In this work, the study is performed on a specific biofluid, viz. human blood. Assume that the magnetization very linearly with magnetic field strength, temperature dependency of dynamic viscosity and thermal conductivity is noticed. A system of non-linear equations with appropriate boundary condition is obtained by familiarizing suitable non-dimensional variables in the physical problem. For the numerical solution, we used finite difference method which is based on an efficient technique is applied in the problem. Computations for flow profiles, local skin friction coefficient and local heat transfer coefficient are performed with the magnetic parameter Mn, the viscosity/temperature parameter θr and the thermal/conductivity parameter S∗. The effect of the localized heating or cooling is examined. The computational results presented graphically and have been validated in an appropriate manner. The study reveals that the impact of a magnetic field for blood flow in arteries is found significantly. The results presented bear the promise of valuable applications in physiology, medicine and bioengineering.

Influence of solvent viscosity ratio on the creeping flow of viscoelastic fluid over a channel confined circular cylinder

In this study, the role of solvent viscosity ratio (β) on the creeping flow characteristics of Oldroyd-B fluid over a channel-confined circular cylinder has been explored numerically. The flow governing equations have been solved by RheoTool, an open-source toolbox based on OpenFOAM, employing the finite volume method for extensive ranges of Deborah number (De=0.025–1.5) and solvent viscosity ratio (β=0.1–0.9) at a fixed wall blockage (B = 0.5). The present investigation has undergone extensive validation, with available literature under specific limited conditions, before obtaining detailed results for the relevant flow phenomena, such as stream function, pressure and stress contour profiles, pressure coefficient (Cp), wall shear stress (τw), normal stress (τxx), first normal stress difference (N1), and drag coefficient (CD). The flow profiles have exhibited a distinctive behavior characterized by a loss of symmetry in the presence of pronounced viscoelastic effects. The results for low De notably align closely with those for Newtonian fluids, and the drag coefficient (CD) remains relatively constant regardless of β, as the viscoelastic influence is somewhat subdued. These observations indicate that at high De and low β, viscoelasticity causes asymmetry in creeping flow around a circular cylinder. With an increase in De, the maximum velocity in gap between cylinder and channel walls increases; however, the cylinder experiences significantly less drag force. Within this parameter range, the prevailing force governing the flow is the pressure drag force.

Stability of plane Couette flow under anisotropic superhydrophobic effects

We study the linear stability of plane Couette flow subject to an anisotropic slip boundary condition that models the slip effect of parallel microgrooves with a misalignment about the direction of the wall motion. This boundary condition has been reported to be able to destabilize channel flow far below the critical Reynolds number of the no-slip case. Unlike channel flow, the no-slip plane Couette flow is known to be linearly stable at arbitrary Reynolds numbers. Nevertheless, the results show that the slip can cause linear instability at finite Reynolds numbers also. The misalignment angle of the microgrooves that maximizes the destabilizing effect is nearly π/4, and the unstable modes are of small streamwise wavenumbers and relatively large spanwise wavenumbers. The flow is always more destabilized by two slippery walls compared to a single slippery wall. These observations are in qualitative agreement with the slippery channel flow with the same boundary condition, indicating that such an anisotropic superhydrophobic effect has a rather general destabilizing effect in shear flows regardless of the profile of the base flow. The absence of the Tollmien–Schlichting instability allows us to reveal the inverse relationship between the critical Reynolds number and the slip length as well as the misalignment in the small-parameter regime. The results suggest that arbitrary nonvanishing slip length and misalignment, with arbitrarily weak anisotropy, may suffice to destabilize plane Couette flow.

Investigation of geometrical hopper and initial packing state on the inter-phase momentum transfer with granular flow in vertical packed bed

Abstract For the specific application of vertical packed bed design, the main task is to optimize and improve the granular flow pattern, since a worse granular flow pattern is detrimental to the performance of heat transfer and flow in vertical packed bed. To improve the uniformity of granular flow profiles, an application of the discrete element method is used to investigate the granular flow pattern in a vertically packed bed under the condition of different tapered hopper angles and initial packing states. The uniformity of granular dramatically decreases with an increase in the fluctuation of granular velocity distribution. The variation of structural parameters has a positive influence on enhancing the stability of the granular layer. Coefficient of variation and relative fluctuation kinetic energy are introduced as criteria to describe the stability of the granular layer. This study numerically reveals the evolution of initial packing states has a slight influence on improving the stability of granular flow.

Simulations of nozzle gas flow and gas-puff Z-pinch implosions on the Weizmann Z-pinch

We present simulations of an oxygen gas puff Z-pinch on a University scale generator at the Weizmann Institute of Science. The work accounts for the detailed geometry of the nozzle, the initial neutral gas density distribution, and the subsequent implosion. The modeling results show significant improvement with data for the current at the time of stagnation in comparison with a previous effort [Rosenzweig et al., Phys. Plasmas 27, 022705 (2020)]. As a first step, we performed simulations of the flow of neutral diatomic oxygen from a plenum through a nozzle within a recessed cathode, across a gap, and into the anode with a recessed grounded honeycomb. These simulations show an agreement with the measured initial gas density profiles within the region not blocked by the recesses and accessible to visible measurements. The computed neutral gas flow profile serves as the initial condition for a radiation magnetohydrodynamic simulation of the implosion using the MACH2-TCRE code. By considering the specific details of the nozzle and chamber geometry, we find agreement with the measured current profile, including the inductive notch. The simulations predict that the plasma undergoes a strong pinch within the hidden anode recess. The simulations also predict the strongest radiation pulse occurs within the anode recess and at the time of the observed inductive notch.

Characterization of internal jugular vein region-specific distension and flow patterns during progressive volume shifting.

Blood volume shifts during postural adjustment leads to irregular distension of the internal jugular vein (IJV). In microgravity, distension may contribute to flow stasis and thromboembolism, though the regional implications and associated risk remain unexplored. We characterized regional differences in IJV volume distension and flow complexity during progressive head-down tilt (HDT) (0°, -6°, -15°, -30°) using conventional ultrasound and vector flow imaging. We also evaluated low-pressure thigh cuffs (40 mmHg) as a fluid shifting countermeasure during -6° HDT. Total IJV volume expanded 139±95% from supine (4.6±2.7 mL) to -30° HDT (10.3±5.0 mL). Blood flow profiles had greater vector uniformity at the cranial IJV region (P<0.01) and became more dispersed with increasing tilt (P<0.01). Qualitatively, flow was more uniform throughout the IJV during its early flow cycle phase, and more disorganized during late flow phase. This disorganized flow was accentuated closer to the vessel wall, near the caudal region, and during greater HDT. Low-pressure thigh cuffs during -6° HDT decreased IJV volume at the cranial region (-12±15%; P<0.01) but not the caudal region (P=0.20), although flow uniformity was unchanged (both regions,P>0.25). We describe a distensible IJV accommodating large volume shifts along its length. Prominent flow dispersion was primarily found at the caudal region, suggesting multi-directional blood flow. Thigh cuffs appear effective for decreasing IJV volume but effects on flow complexity are minor. Flow complexity along the vessel length is likely related to IJV distension during chronic volume shifting and may be a precipitating factor for flow stasis and future thromboembolism risk.

Atypical applications of transverse diffusion of laminar flow profiles methodology for in-capillary reactions in capillary electrophoresis.

Capillary electrophoresis (CE) is a powerful separation technique offering quick and efficient analyses in various fields of bioanalytical chemistry. It is characterized by many well-known advantages, but one, which is perhaps the most important for this application field, is somewhat overlooked. It is the possibility to perform chemical and biochemical reactions at the nL scale inside the separation capillary. There are two basic formats applicable for this purpose, heterogeneous and homogeneous. In the former, one reactant is immobilized onto a particle or monolithic support or directly on the capillary wall, and the other is injected. In the latter, the reactant mixing inside a capillary is based on electromigration or diffusion. One of the diffusion-based methodologies, termed Transverse Diffusion of Laminar Flow Profiles, is the subject of this review. Since most studies utilizing in-capillary reactions in CE focus on enzymes, which are being continuously and exhaustively reviewed, this review covers the atypical applications of this methodology, but still in the bioanalytical field. As can be seen from the demonstrated applications, they are not limited to reactions, but can also be utilized for other biochemical systems.

THE ROLE OF SURROGATE MODELS AND MACHINE LEARNING IN MODERN ULTRASONIC FLOW MEASUREMENT

Recent developments in the field of machine learning have found their application in a wide range of design processes. They have particular use where numerical simulations are involved and fast, more accurate predictions and optimized models are very much needed. In order to speed up experiments on a device or system model, it is necessary to speed up its execution (simulation). Instead of detailed models, you can create a surrogate. Its main task is fast execution, small amount of occupied memory and preservation of the specified error threshold in relation to the detailed model. This article demonstrates the integration of machine learning into the flow measurement process using ultrasonic flowmeters. The main source of errors in the application of the modern ultrasonic principle of flow measurement arises from the difficulty of taking into account the actual velocity profile of the measuring flow. In practice, the distribution of velocities in the cross-section of the pipeline differs from the theoretical one introduced in the calculation algorithm. However, if the velocity profile is known, an appropriate correction can be estimated and taken into account during calibration. This will increase the accuracy of measurements. In this study, an intelligent compensation of errors caused by profile distortion was presented to improve the accuracy of using multipath meters in such ultrasonic conditions. The purpose of such an intelligent correction arises in the search for the optimal layout and the minimum sufficient number of chords in the measuring transducer for various installation conditions. The adoption of a new approach based on a surrogate model with a neural network made it possible to take an approximate flow profile that has a certain distortion. So, for the chosen topology of the acoustic flow sensing channels, programmatically, by changing the location angle of the measuring system, instead of the local resistance, add such a position of the chords for which it is possible to set maximum admissible measurement accuracy. This means using a neural network for the required input correction model, especially in an environment characterized by a change in the velocity profile under the influence of different flow distortions.

Analisis Kapasitas Efektif Tampungan Kali Pancir

Kali Pancir is one of the rivers in Jombang Regency which often experiences flooding. The cause was heavy rain and the critical condition of the embankments. In this research, flood discharge analysis was carried out using synthetic hydrographs and hydraulic modeling for river flow. The data needed is rain data from rain stations around the Pancir River and river profiles. The method used to calculate flood discharge is the Nakayasu Synthetic Unit Hydrograph for 6 different return periods. Simulation using HEC-RAS software is used to simulate flow profiles to determine river cross-sections that are critical to flooding. Based on the results of the calculation analysis, it was found that the peak flood discharge occurred at 3.5 hours. The greater the return period, the greater the river cross section that experiences overflow. At a return period of 1.01 years, the critical cross section starts at STA 45, while at a return period of 50 years, the critical cross section occurs starting at STA 6.

Redox-mediated Biomolecular information transfer in single electrogenetic biological cells

Electronic communication in natural systems makes use, inter alia, of molecular transmission, where electron transfer occurs within networks of redox reactions, which play a vital role in many physiological systems. In view of the limited understanding of redox signaling, we developed an approach and an electrochemical–optical lab-on-a-chip to observe cellular responses in localized redox environments. The developed fluidic micro-system uses electrogenetic bacteria in which a cellular response is activated to electrically and chemically induced stimulations. Specifically, controlled environments for the cells are created by using microelectrodes to generate spatiotemporal redox gradients. The in-situ cellular responses at both single-cell and population levels are monitored by optical microscopy. The elicited electrogenetic fluorescence intensities after 210 min in response to electrochemical and chemical activation were 1.3 × 108±0.30 × 108 arbitrary units (A.U.) and 1.2 × 108±0.30 × 108 A.U. per cell population, respectively, and 1.05 ± 0.01 A.U. and 1.05 ± 0.01 A.U. per-cell, respectively. We demonstrated that redox molecules' mass transfer between the electrode and cells – and not the applied electrical field – activated the electrogenetic cells. Specifically, we found an oriented amplified electrogenetic response on the charged electrodes' downstream side, which was determined by the location of the stimulating electrodes and the flow profile. We then focused on the cellular responses and observed distinct subpopulations that were attributed to electrochemical rather than chemical stimulation, with the distance between the cells and the stimulating electrode being the main determinant. These observations provide a comprehensive understanding of the mechanisms by which diffusible redox mediators serve as electron shuttles, imposing context and activating electrogenetic responses.