Changes In Flow Rate Research Articles

Effectiveness and safety of mesenchymal stem/stromal cell for radiation-induced hyposalivation and xerostomia in previous head and neck cancer patients (MESRIX-III): a study protocol for a single-centre, double-blinded, randomised, placebo-controlled, phase II study

BackgroundA predominant side effect of radiotherapy for head and neck cancer is salivary gland hypofunction and xerostomia leading to debilitating oral disorders and impaired quality of life (QoL). Intraglandular mesenchymal stem cell therapy has shown promising results as a treatment for xerostomia.MethodsThis is a randomised, double-blinded, placebo-controlled, parallel-group, prospective, single-centre trial investigating the safety, tolerability, and effectiveness of allogeneic stem cells as a treatment for radiation-induced hyposalivation and xerostomia for previous head and neck cancer patients.We will include a total of 120 patients who previously have been treated with radiotherapy for a head and neck cancer in Denmark. Participants will be randomly assigned using block randomisation to one of two parallel groups in a 1:1 ratio to receive ultrasound-guided injection of allogeneic adipose-derived mesenchymal stem cell (ASC) (n = 60) or placebo (n = 60) into the submandibular glands. Placebo will consist of CryoStor10 (BiolifeSolutions), the freeze media for ASCs containing 10% dimethyl sulfoxide (DMSO). The primary endpoint is change in unstimulated whole saliva flow rate. The secondary endpoints are change in stimulated whole saliva flow rate, QoL, and composition of saliva. Further secondary endpoints are safety and immune response (human leukocyte antigen (HLA) response) to the stem cells will be assessed. Patients are evaluated at baseline (before treatment), after 4 months, and after 12 months. All study personnel, except study personnel thawing and preparing the treatment for injection, and participants will be blinded to group assignment. Unblinded study personnel will not participate in the outcome assessment.DiscussionThe trials will investigate the efficacy and safety of ASC injection to the submandibular gland as a potential new treatment for post-radiation xerostomia. We hope the results will pave the way for a clinically relevant treatment to ameliorate patients with xerostomia, a severely hampering condition.Trial registrationThe study is approved by the Danish Data Protection Agency (protocol number P-2020-1164), the National Ethics Committee protocol number: (Protocol number: 1802872), and the Danish Medical Agency (2018-000348-24). The protocol was registered at the ClinicalTrials.gov database (NCT04776538).

Numerical Simulation of Heat Transfer Characteristics of Finned Tube Heat Exchanger at Different Flow Velocities

A heat exchanger is an important component where high-temperature hot air and normal-temperature water exchange heat. The heat exchange area of the finned tube heat exchanger is calculated by the rated working conditions. However, with the decrease of the heat storage temperature, the hot air temperature at the outlet of the thermodynamic energy storage device changes in a large range, directly affecting the heat exchange capacity and efficiency of the finned tube heat exchanger. This paper’s three-dimensional model is established. The heat exchanger of the finned tube is designed according to the temperature of the outlet section and the return section temperature of the heat storage system. The thermodynamic physical parameter property and characteristics of which heat exchanger’s finned tube in the air’s velocity range of 1∼10 m/s are simulated by fluent software. The velocity, temperature, pressure, and heat exchanger coefficient distribution characteristics at different positions along the airflow direction are obtained. The simulation results show that the mean flow velocity is 2.0 m/s and 5.0 m/s at the inlet cross-section. The average temperature difference between the inlet and outlet is 69.5 K and 100.5 K, respectively. The fin surface temperature difference between the first and eighth rows of finned tubes is 12.5 K and 14.4 K, respectively. The air pressure loss at the air channel inlet’s section and outlet’s section is 16.1 Pa and 69.4 Pa, respectively. When the inlet flow rate change from starting at 1.0 m/s and ending at 10.0 m/s, the tube’s wall coefficient of heat transfer, which is the second level of finned tubes, only increases by 1.8 times. The tube’s wall coefficient of heat transfer of the eighth level of finned tubes increases by the maximum, to 5 times the original, but the heat energy exchange capacity of which the second level of finned tubes is always the strongest.

EVALUATING CHANGES IN SALIVARY FLOW RATE, PH & MICROBIAL COUNT DURING FIXED ORTHODONTIC TREATMENT - AN IN VIVO STUDY

Aim of the study: Aim of this study is to assess the changes in salivary flow rate, salivary pH, plaque index, Streptococcus mutans, Lactobacillus, and Candida albicans in patients undergoing fixed orthodontic treatment, before and after placement of fixed orthodontic appliances. Materials and Method: In present study salivary samples from 60 patients (30 Males and 30 Females) with age group of 14-25 years would be undergoing fixed orthodontic treatment at the department of orthodontics. Salivary flow rate, pH, plaque index and microbial colony count were measured. Streptococcus mutans, Lactobacillus and Candida albicans colony counts were measured using mitis salivarius agar, rogosa agar and sabouraud dextrose agar respectively. Saliva collected for 5 mins and measured in ml/min. salivary pH measured with digital pH meter. Salivary samples obtained from the same patients at intervals of 8 weeks and 16 weeks after commencement of orthodontic treatment and evaluated for the same. Result: This study showed fixed orthodontic appliances increases salivary flow rate (p=0.0001), decreases salivary pH (p=0.03), increases plaque index (p=0.0001), also increases Streptococcus mutans, Lactobacillus and Candida albicans colony count (p=0.0003, p=0.0001and p=0.019 respectively). Independent t test reported salivary flow rate significantly increases more in male patients at 16 weeks interval (p=0.03). Conclusion: The results of this study confirmed that after placement of fixed orthodontic appliances plaque retention increases, which sequentially decrease the salivary pH and decreased salivary pH promote the growth of microbiota.

Cardiac Vagal Nerve Activity Increases During Exercise to Enhance Coronary Blood Flow.

The phrase complete vagal withdrawal is often used when discussing autonomic control of the heart during exercise. However, more recent studies have challenged this assumption. We hypothesized that cardiac vagal activity increases during exercise and maintains cardiac function via transmitters other than acetylcholine. Chronic direct recordings of cardiac vagal nerve activity, cardiac output, coronary artery blood flow, and heart rate were recorded in conscious adult sheep during whole-body treadmill exercise. Cardiac innervation of the left cardiac vagal branch was confirmed with lipophilic tracer dyes (DiO). Sheep were exercised with pharmacological blockers of acetylcholine (atropine, 250 mg), VIP (vasoactive intestinal peptide; [4Cl-D-Phe6,Leu17]VIP 25 µg), or saline control, randomized on different days. In a subset of sheep, the left cardiac vagal branch was denervated. Neural innervation from the cardiac vagal branch is seen at major cardiac ganglionic plexi, and within the fat pads associated with the coronary arteries. Directly recorded cardiac vagal nerve activity increased during exercise. Left cardiac vagal branch denervation attenuated the maximum changes in coronary artery blood flow (maximum exercise, control: 63.5±5.9 mL/min, n=8; cardiac vagal denervated: 32.7±5.6 mL/min, n=6, P=2.5×10-7), cardiac output, and heart rate during exercise. Atropine did not affect any cardiac parameters during exercise, but VIP antagonism significantly reduced coronary artery blood flow during exercise to a similar level to vagal denervation. Our study demonstrates that cardiac vagal nerve activity actually increases and is crucial for maintaining cardiac function during exercise. Furthermore, our findings show the dynamic modulation of coronary artery blood flow during exercise is mediated by VIP.

Structural Stress Intensity Analysis of Hybrid Heat Exchangers Based on Thermal Hydraulic Performance in S-CO2 Power Cycle

Abstract Hybrid heat exchangers (H2Xs) can be used for heat exchange equipment between high-temperature exhaust gas from ships and high-pressure supercritical carbon dioxide (S-CO2) from the S-CO2 power cycle. We investigate structural stress intensity characteristics of the H2Xs based on thermal-hydraulic performance. Air and S-CO2 are employed as the working fluids and the Stainless Steel 316 (SS316) as the solid substrate. The thermal-hydraulic performance and structural stress intensity characteristics of the H2Xs are conducted by Ansys Fluent and Mechanical, respectively. The results show the mechanical stress induced by pressure loading and the thermal stress induced by temperature gradient are found to be equally important sources of stress intensity. At the inlet and outlet of the H2Xs, the total stress intensity along all paths is not smooth and continuous, and there will be a significant change due to the change in the temperature gradient. The mechanical stress caused by the fluid pressure loss is almost negligible. The change in inlet mass flowrate and temperature mainly affects the stress intensity distribution of the left and right walls on the fin channel. The pressure variation of the diesel engine has little effect on the total stress intensity. Importantly, the total stress intensity of the H2X is mainly affected by the change in S-CO2 fluid pressure.

A Microfluidic Flow Sensor Based on CuO Nws Enhanced Solid-Liquid Contact Electrification for Trapping Platelets on Collagen and Its Quantification

Platelet number plays an important role in several kinds of diseases such as leukemia, hepatitis C, diabetes, COVID-19, microbial infections, etc. These diseases can result in thrombocytopenia, a condition where patients suffer from reduced platelets, thus requiring the need to frequently monitor the platelet count. Currently existing techniques are complex, costly, and time consuming. The target diseases continue to evolve urging the need to develop rapid, facile point-of-care devices with high precision. In this regard, the current study is focused on the development of a platelet quantification technique based on trapping of platelets in a microfluidic channel adhered with collagen layer, and CuO NWs grown on Cu tube integrated on both the sides of the channel. This trapping of platelets results in a change in the triboelectric output performance from solid-liquid contact electrification due to change in flow rate of platelet content in the plasma. These changes in triboelectric output are enhanced by CuO NWs due to its high surface-area-to-volume ratio. The study of flow sensing by integrating the microfluidic device with solid-liquid contact electrification has been reported for the first time. The flow sensing signal was optimized by variation in viscosity of the flowing liquid, channel geometry, flow rate, and triboelectric voltage measuring methods. The platelet rich plasma (PRP) and platelet poor plasma (PPP) were prepared and mixed in different ratios to prepare the solutions with different concentration of platelets (0% - 100%). The calibration curve for platelet quantification has shown a variation of 9 V for change in platelet concentration from 0% to 100%. The proposed device exhibited a linear response with the variation in platelet counts. The obtained results prove its potential and feasibility as a point-of-care device.

Long-Term Change in Flow Rates in Patients with Coronary Slow Flow

Introduction: Coronary slow flow (CSF) is a condition characterized by impaired blood flow rates in the coronary arteries. It can result in severe cardiovascular outcomes. There is no sufficient evidence regarding the certain etiology and reversibility of slow flow patterns and changes in frame counts with long-term management. Methods: We retrospectively enrolled 48 patients with chronic coronary syndrome and CSF who underwent a second angiography. A corrected coronary frame rate (CFR) >27 was defined as CSF. We created 3 groups according to the change in CSF status as the improved, not changed, and worsened groups. We compared the CFR and CSF status of the patients between the first and second angiographies within a median of 2.6 years. Results: We determined a nonsignificant change in cCFR in left anterior descending (LAD) artery (34.4 [18.9] vs. 31.59 [10.3], p = 0.35), circumflex (Cx) artery (42.84 [12.56] vs. 40.66 [13.2], p = 0.35), and right coronary artery (RCA) (57.80 [30.13] vs. 50.32 [19.5], p = 0.11). In the comparison of CSF status of LAD (75% vs. 63%, p = 0.27), Cx (96% vs. 83%, p = 0.09), RCA (94% vs. 94%, p = 1.0) between first and second angiographies, there was no significant change. In the comparison of the 3 groups according to the improvement of CSF status, there was no significant difference in demographic features, change in laboratory parameters, and time between the groups. Conclusion: There was no significant change in the median CFR and CSF status in the overall group between the two angiographies after 3 years.

Eulerian simulations of local liquid distribution in a Trickle Bed: Effects of flow rates and liquid properties

We performed Eulerian simulations of gas–liquid flow in a Trickle Bed Reactor (TBR) to understand contributions of gas–liquid, gas–solid and liquid–solid interaction forces (F→GL,F→GS,F→LS), capillary-pressure (F→C) and mechanical-dispersion (F→D) forces to local liquid spreading and how their contributions change with changes in flow rates and physical properties. Further, we simulated effects of these parameters on pressure drop (ΔP), overall liquid hold-up (〈εL〉) and importantly on local liquid spreading and validated the predictions using measurements. We have shown that F→LS significantly contributes to local liquid spreading, ΔP and 〈εL〉, whereas F→D contributes marginally. The modified F→LS model led to satisfactory predictions of local liquid spreading, ΔP and 〈εL〉 for a wide range of fluid flow rates and physical properties and predictions are in a satisfactory agreement with the measurements. The present work is an important step in extending the CFD model for simulating reactions and heat effects in TBRs.

Experimental investigation of hydrogen production performance of various salts with a chlor-alkali method

In this experimental study, the hydrogen production performance of aqueous solutions of NaCl, KCl, and CaCl2 salts via an electrochemical method through a chlor-alkali reactor is investigated. For this purpose, a laboratory-scale reactor consisting of anode and cathode compartments is built. The compartments of the reactor are separated by a cation exchange membrane which prevents the mixing of anolyte and catholyte solutions and also allows positive ions (Na+, K+, and Ca2+) and some water to pass through. Electrodes made of 316 stainless steel are used in the compartments of the reactor due to their economic efficiency. While the anode compartment of the reactor is fed with the aqueous solutions of NaCl, KCl, and CaCl2 salts one by one, the cathode compartment is fed with one of the diluted aqueous solutions of NaOH, KOH, and Ca(OH)2 bases depending on the type of salt used. Experiments are carried out at three different cell voltages (3, 4, and 5 V) and three different cell temperatures (30, 50, and 70 °C), and five different electrolyte flows (0.4, 0.6, 0.8, 1.0, and 1.2 g/s). Since the reactor dimensions are very small, experiments are also carried out with small changes in the electrolyte mass flow rate. It is observed that active chlorine gas causes serious contamination in the anode compartment and erosion on the electrode in this compartment. Therefore, the expected chlorine gas output from the anode compartment of the reactor is not observed. Luckily, a significant amount of hydrogen gas output is observed from the cathode compartment of the reactor. The minimum hydrogen production rate is 37.23 mL/h when the aqueous solution of CaCl2 is used with a mass flow rate of 0.4 g/s and cell voltage of 3 V at the cell temperature of 30 °C. The maximum hydrogen production rate is 437.72 mL/h when KCl salt solution is used with a mass flow rate of 1.2 g/s and cell voltage of 5 V at the cell temperature of 70 °C.

Numerical Simulation of Soot Formation in Ethylene Laminar Diffusion Flame

The soot produced by fossil fuel combustion affects climate and human health, and the ethylene laminar flame is a crucial research object of soot generation. After verifying the accuracy of the numerical calculation model by comparing experimental data, the impact of changes in inlet flow rate and fuel flow composition operating conditions on the generation of soot were compared and analyzed. The calculated results obtained are consistent with the experimental data in terms of distribution trend. The deviation of the calculated peak integral smoke volume fraction is only 5%. Under the operating conditions set in this study, increasing the volume flow rate of the accompanying air will increase the volume fraction of soot generated by the ethylene laminar diffusion flame. Increasing the fuel volume flow rate will first increase and then decrease the volume fraction of soot.

Multilevel method for predicting flow fields in radial turbines based on sparsity-promoting dynamic mode decomposition

PurposeThe purpose of this study is to propose a fast method for predicting flow fields with periodic behavior with verification in the context of a radial turbine to meet the urgent requirement to effectively capture the unsteady flow characteristics in turbomachinery. Aiming at meeting the urgent requirement to effectively capture the unsteady flow characteristics in turbomachinery, a fast method for predicting flow fields with periodic behavior is proposed here, with verification in the context of a radial turbine (RT).Design/methodology/approachSparsity-promoting dynamic mode decomposition is used to determine the dominant coherent structures of the unsteady flow for mode selection, and for flow-field prediction, the characteristic parameters including amplitude and frequency are predicted using one-dimensional Gaussian fitting with flow rate and two-dimensional triangulation-based cubic interpolation with both flow rate and rotation speed. The flow field can be rebuilt using the predicted characteristic parameters and the chosen model.FindingsUnder single flow-rate variation conditions, the turbine flow field can be recovered using the first seven modes and fitted amplitude modulus and frequency with less than 5% error in the pressure field and less than 9.7% error in the velocity field. For the operating conditions with concurrent flow-rate and rotation-speed fluctuations, the relative error in the anticipated pressure field is likewise within an acceptable range. Compared to traditional numerical simulations, the method requires a lot less time while maintaining the accuracy of the prediction.Research limitations/implicationsIt would be challenging and interesting work to extend the current method to nonlinear problems.Practical implicationsThe method presented herein provides an effective solution for the fast prediction of unsteady flow fields in the design of turbomachinery.Originality/valueA flow prediction method based on sparsity-promoting dynamic mode decomposition was proposed and applied into a RT to predict the flow field under various operating conditions (both rotation speed and flow rate change) with reasonable prediction accuracy. Compared with numerical calculations or experiments, the proposed method can greatly reduce time and resource consumption for flow field visualization at design stage. Most of the physics information of the unsteady flow was maintained by reconstructing the flow modes in the prediction method, which may contribute to a deeper understanding of physical mechanisms.

Numerical investigation of tip clearance flow in a variable geometry turbine with non-uniform partial clearance

Abstract In variable geometry turbine vanes, tip clearance height and shape vary with the rotation of the vane, which affect the aerodynamic performance significantly. However, these issues are rarely considered in published studies. The current paper investigated the flow field features of transonic variable geometry turbine vanes with non-uniform partial clearance induced by the vane rotating. The results show that: The influence of guide vane rotation on the clearance height and its distribution cannot be ignored. At the same turning angle, the maximum clearance difference is up to 0.79 mm (0.8 % vane height). The height and shape variation of the non-uniform clearance leads to the change in the leakage flow rate, secondary flow structure, and aerodynamic loss of the variable guide vane. Under the combined effect of pressure difference on both sides of the clearance, axial and circumferential non-uniformity of clearance height, the total pressure loss coefficient is up to 9.44 % when the turning angle is −10°. The effect of the pivot on the clearance flow was also analyzed. The pivot increases the pressure in the gap flow field and reduces leakage flow velocity. However, a backflow region appears at the suction side of the pivot, which increases the aerodynamic losses.

Long Term Antidepressant Effects of Deep Brain Stimulation for Treatment Resistant Depression – A Research Protocol

Introduction: Individuals with treatment resistant depression (TRD) are those with severe major depressive disorder who fail to respond to conventional pharmacological treatment. As a result, novel technologies in the field of neuromodulation have been investigated to alleviate depressive symptoms in this population. One such neuromodulation therapy is deep brain stimulation (DBS), in which electrodes are neurosurgically implanted into target regions of the brain associated with depression, such as the subgenual anterior cingulate cortex (sgACC). While previous studies have explored the use of DBS as a therapy for TRD, few studies with adequate statistical power have explored the sustained antidepressant effects of DBS when targeting the sgACC of the brain. Methods: This study aims to explore the long-term effects in DBS patients for TRD by measuring changes in cerebral blood flow and cerebral metabolic rate in the sgACC, and its correlation to changes in self-reported depressive symptoms. Forty-five participants will be enlisted into this study. Psychometric evaluation and positron-emission topography imaging will be conducted prior to neurosurgery. Electrodes will be implanted into the sgACC, with extension wires attaching the electrodes to the internal pulse generator. In the six-week blinded phase, progressive increases in stimulation will be administered within the blinded group and sham stimulation in controls. The three-month open label phase will administer the same degree of high-frequency biphasic stimulation to the control and blinded groups and assess depression scores, neuroimaging, and adverse events. After cessation of active stimulation, a one-year, three-year, seven-year, and ten-year follow-up will monitor changes in antidepressant effects of DBS using simple linear contrasts and paired-sample t-tests. Expected Results: This study expects to find a sustained antidepressant response marked by decreases in sgACC metabolism and cerebral blood flow, and a reduction in self-report depression scores. Discussion: The use of DBS shows promise as a successful treatment intervention with sustained long-term effects for individuals with TRD. Additional secondary outcomes to be expected are improved quality of life and health behaviours. Conclusion: Though minor fluctuations are expected due to the presence of comorbidities, this study expects to showcase the long-term efficacy of deep brain stimulation for treatment resistant depression.

Quantifying the relationship between spreading depolarization and perivascular cerebrospinal fluid flow

Recent studies have linked spreading depolarization (SD, an electro-chemical wave in the brain following stroke, migraine, traumatic brain injury, and more) with increase in cerebrospinal fluid (CSF) flow through the perivascular spaces (PVSs, annular channels lining the brain vasculature). We develop a novel computational model that couples SD and CSF flow. We first use high order numerical simulations to solve a system of physiologically realistic reaction–diffusion equations which govern the spatiotemporal dynamics of ions in the extracellular and intracellular spaces of the brain cortex during SD. We then couple the SD wave with a 1D CSF flow model that captures the change in cross-sectional area, pressure, and volume flow rate through the PVSs. The coupling is modelled using an empirical relationship between the excess potassium ion concentration in the extracellular space following SD and the vessel radius. We find that the CSF volumetric flow rate depends intricately on the length and width of the PVS, as well as the vessel radius and the angle of incidence of the SD wave. We derive analytical expressions for pressure and volumetric flow rates of CSF through the PVS for a given SD wave and quantify CSF flow variations when two SD waves collide. Our numerical approach is very general and could be extended in the future to obtain novel, quantitative insights into how CSF flow in the brain couples with slow waves, functional hyperemia, seizures, or externally applied neural stimulations.

PARAMETERS OF THE ST-40M HALL THRUSTER WITH INCREASED POWER DISCHARGE SUPPLY


 
 
 Abstract. The article presents the results of experimental investigation of the ST-40M Hall thruster modification developed by the Space Electric Thruster Systems (SETS). The thruster used a new filament hollow cathode with an emitting insert made of lanthanum hexaboride (LaB6). The use of a new hollow cathode made it possible to study the thruster’s parameters in the discharge power range of 300 – 550 W. The investigation was carried out using a stabilized voltage supply as a discharge power supply. As a result of experimental investigation, the current-voltage characteristics of the discharge in the accelerating channel of the thruster were obtained at fixed values of the anode’s mass flow rate of the working gas - xenon. The experimental dependences of thrust on the anode’s mass flow rate of the working substance and the discharge voltage, as well as the dependences of the specific impulse and thruster efficiency on the discharge voltage, are obtained. Experimental studies have shown that with a change in the discharge voltage in the range of 250 – 400 V and a change in the mass flow rate of the working gas in the range of 0.9 – 2.2 mg/s, the thruster provides a thrust value of 12 – 33 mN, a specific impulse value of 1200 – 1800 s, and the maximum value of the anode’s efficiency is 48 – 52%. The article also contains oscillogramsillustratingtherepeatedprocessofthethrusterstarting. Experimentalinvestigationofthemodified thruster ST-40M with the new hexaboride hollow cathode showed a significant improvement in thruster parameters compared to the prototype parameter before modification. In the process of experimental investigation, it was found that in some modes of the thruster operation, significant fluctuations in the discharge current occur, which led to a significant decreasing in the thruster parameters. For a more accurate clarification of the nature and parameters of the discharge current oscillations, it is necessary to conduct additional studies. The obtained experimental parameters of the modified ST-40M thruster made it possible to determine the values of its optimal parameters for various space missions.
 
 

Transient Study (Annual) of the Heat Transfer of a Two-Channel Solar Air Collector

Abstract In this paper, a numerical heat transfer study of a solar air collector with two channels (SAC-2C) was carried out. Energy global balances in two dimension (2D) and unsteady state were considered, as well as bio-climatic conditions of Toluca city in Mexico (sub-humid temperate climate). Six mass flowrates (0.01, 0.05, 0.1, 0.2, 0.4, and 0.5 kg/s) were considered during the numerical simulation, for the coldest and the warmest day of each month during a complete year (2019). Among the results, it was found that thermal efficiency of the system increases up to 35% when the mass flowrate changes from 0.01 to 0.2 kg/s, meanwhile, maximum efficiency of 84% were obtained for a mass flowrate of 0.5 kg/s. Finally, based on a cost-benefit analysis, it was determined that the SAC-2C has a recovery time of the initial investment ($ 250 USD) of three and a half years. So that the SAC-2C has the capacity to produce 1, 654, 451 kW h/m2 of clean energy annually, which is equivalent to ceasing to produce 871, 895 kg CO2 per square meter of installation.

The development of simultaneous transducer ultrasonic with dual-transducer to measure flow velocity in the pipe

There are still several obstacles to calculating fluid flow rate measurement on custody transfer, such as the distribution of one-phase fluid flow rate, less sTable pressure, and fluid flow rate changes, which are still the main problems in the process of a measuring system. To calculate the flow rate of one phase fluid, there is a method often used, namely transit time. In practice, the transit time works to send the ultrasonic pulse from upstream to downstream, which had to have a delay because the transducer must switch the function of a transducer to become transmitter or receiver. So, this paper proposed a new strategy of measurement multipath ultrasonic flowmeter (UFLW) with a simultaneous transit time method using a dual transmitter and receiver. The simultaneous method is a measuring technique that utilizes a pair of ultrasonic transducers as both trigger and receiver. The first transducer serves as the transmitter, while the second functions as the receiver, capturing the signal at the same time without changing their positions or roles. In order to implement the configuration setup, let’s try to use 3 paths configuration with 6 pairs of transducers, 3 on the upstream and 3 on the downstream. To estimate the flow velocity, let’s use long short-term memory (LSTM), which is one of the recurrent neural networks (RNN) architectures in the deep learning algorithm, and to evaluate the performance, let’s use the Bland-Altman plot and root mean squared error (RMSE) and validation loss of the LSTM model. The result shows RMSE 0.289 from the actual flow velocity, which means an LTSM with simultaneous multipath ultrasonic can reduce the error between prediction and actual measurement

Development of a calculation scheme for selecting the optimal mode of operation of a gas condensate well taking into account the deformation conditions of the formation

To establish premature optimal well operation modes, it is necessary to consider the process of well operation within the framework of ongoing processes in the common reservoir-well hydrodynamic system and take into account the peculiarities of changes in the properties of the gas condensate mixture and the thermobaric conditions of the reservoir in it. Therefore, the object of the study is the operation of a gas condensate well in the event of technological complications in it, which requires the selection of the necessary optimal operating mode to prevent these complications by comprehensively taking into account the factors influencing this process in the “reservoir-well” system.
 The article proposes a calculation scheme for establishing the optimal operating mode of a gas condensate well without the formation of a liquid plug at the bottomhole, taking into account the formation deformation during field development in the depletion mode. The problem is solved by determining the required current working volume of produced gas (as well as condensate), bottomhole and contour values of reservoir pressure, condensate saturation and reservoir porosity. As a result of the study, it was revealed that the determined characteristics of the selected optimal mode of a gas condensate well are significantly affected by a change in the reservoir properties of the reservoir (for example, the permeability of the reservoir), which in turn leads to a change in the optimal working gas flow rate of the well.
 The considered problem has not been previously studied in its full formulation, which is presented in this article, where the solution of the problem under study is achieved taking into account the change in the physical properties of the reservoir fluid and gas, as well as the reservoir properties of the reservoir under conditions of a change in the state of the reservoir system due to emerging deformation processes in the reservoir

Plasma-based CO2 conversion: How to correctly analyze the performance?

Plasma-based CO2 conversion is promising for carbon capture and utilization. However, inconsistent reporting of the performance metrics makes it difficult to compare plasma processes systematically, complicates elucidating the underlying mechanisms and compromises further development of this technology. Therefore, this critical review summarizes the correct definitions for gas conversion in plasma reactors and highlights common errors and inconsistencies observed throughout literature. This is done for pure CO2 splitting, dry reforming of methane and CO2 hydrogenation. We demonstrate that the change in volumetric flow rate is a critical aspect, inherent to these reactions, that is often not correctly taken into account. For dry reforming of methane and CO2 hydrogenation, we also demonstrate inconsistent reporting of energy efficiency, and through numerical examples, we show the significance of these deviations. Furthermore, we discuss how to measure changes in volumetric flow rate, supported by data from two experimental examples, showing that the sensitivity inherent to a standard component and a flow meter is essential to consider when deriving the performance metrics. Finally, some general recommendations and good practices are provided. This paper aims to be a comprehensive guideline for authors, to encourage more consistent calculations and stimulate the further development of this technology.

Studying the impact of impeller geometrical parameters on the high-efficiency working range of pump as turbine (PAT) installed in the water distribution network

The development plan for micro hydropower is expanding with an increasing focus on renewable energy sources. There is increasing attention to using PATs to recover extra hydraulic energy in the water distribution network (WDN) pipelines. In this paper, the performance curves of PAT installed instead of pressure-reducing valves in WDN were investigated. The quality and reliability of numerical simulations were validated compared to the experimental results. Investigating hourly flow rate variations in WDN shows that the PAT working conditions change frequently and operate for a long time under off-design conditions. Since there are no tools to control and guide the fluid to the impeller, there is no proper conformance between the inlet flow and the blade profile, and in this condition loss increases and efficiency decreases. In order to improve the PAT performance in the working range, the effect of modifying parameters of blade thickness, blade number, and blade inlet width is numerically investigated. Optimal geometric parameters for designing a special impeller were determined by considering the flow rate changes of the PRS over 4 working months. Analyzing the PAT performance with a special impeller indicates that losses caused by the flow separation at the leading and trailing edges of the blade as well as the formation of vortices are significantly reduced. Moreover, the fluid's tendency to follow the blade profile is improved due to the flow field form in impeller passages, and the PAT's high-efficiency working range is extended. The greatest increase in efficiency occurs in the overload flow rate (1.2QBEP) and is improved by 6.48%. In this case study, the power generation capacity of the soft pressure regulating system (SPRS) will increase by 5.1% using the special impeller.