Recommended Flow Rate Research Articles

Study on the Flow Velocity of Safe and Energy-Saving Transportation of Light-Particle Slurry

In order to determine the recommended flow velocity for the safe and energy-saving transport of ice-slurry-type light particle slurries, it is necessary to study the flow characteristics of light particle slurries, especially the critical flow velocity. Therefore, in this paper, a numerical simulation method based on the mixed turbulence model with the RANS (Reynolds averaged Navier Stokes) equation is used, and a new concentration distribution method is proposed for the first time to derive the critical flow velocity, as follows: the flow velocity of the light particle slurry when the ratio of the solid volume fraction vf at the position of 0.08D above the bottom of the pipeline to that at the center of the pipeline, vf/vf(y) = 0.75, is taken as the critical flow velocity. The flow changes in the slurry (polyethylene particles with a density of 922 kg/m3 and water) under 0.1–1.0 m/s (at intervals of 0.1 m/s) were investigated experimentally, and the pressure drop data obtained from the experiments were used to determine the recommended flow rate for safe and energy-saving transportation of the light particle slurry. The pipe diameter used for the experiments and simulations was 28 mm, and the solid-phase particle sizes were 0.3 mm, 0.4 mm, and 0.5 mm, with solid-phase contents of 5 vol%, 10 vol%, 15 vol%, and 20 vol%. In addition, the experimental and numerical simulation results show that an increase in solid-phase content and particle size leads to an increase in critical flow velocity.

EVALUATING CUTTING TRANSPORT ON 12 ¼” SECTION WELL TM-1

Mud hydraulics on a 12-1/4" section needs to be planned properly. Mud hydraulics design on a 12-1/4" section includes determining mud density, flow type, pressure loss, pump specifications, bit hydraulics and cutting lifting design. The purpose of bit hydraulics design is to determine the optimum flow rate. Mud hydraulics optimization is carried out using methods the Bit Hydraulic Horse Power (BHHP), Bit Hydraulic Impact (BHI) and Jet Velocity (JV) methods, where the analysis is in the form of graphs. The graph is analyzed by using a trial and error method to obtain the recommended flow rate so as to provide good cutting lifting. where the expected recommendation analysis are Cutting Transport Ratio (Ft) > 90%, Cutting Concentration (Ca) < 5%, and Carrying Capacity Index (CCI) > 1. The analysis results from the graph show that for the hole 12-1/4", it is recommended to use an optimum flow rate of 626.6 gpm with minimum value of Ft is 90.01%, Ca is 0.87% and CCI is 1.95. These values are stated to be good by using 15-15-16 nozzle bit combination. The Flowrate value can be increased up to 785 gpm by using 18-18-20 nozzle bit combination.. Keywords: Hydraulic Mud Planning, Optimum Flow Rate, Cuttings Removal.

Oxygen as an abortive therapy in cluster headache: a narrative review and clinical practice aspects.

Cluster headache (International Classification of Headache Disorders third edition, ICHD-3 3.1) is a primary headache disorder affecting around 0.12% of individuals. It is characterized by severe headache attacks causing significant negative impact on the lives of patients. While administration of 100% oxygen is considered to be the first-choice acute treatment, undertreatment also exists. Reasons for undertreatment may entail problems with the correct prescription of oxygen, reimbursement issues or the practical implementation of home oxygen therapy. The aim of this manuscript is to review the scientific evidence on oxygen therapy for cluster headache and provide a practical guidance for both physicians and patients to optimize its use in an acute setting. The current evidence of the administration of 100% oxygen as a safe and effective treatment for cluster headache is strong. Based on several clinical trials and surveys, the recommended flow rates range between 12 and 15L/min via a non-rebreathing mask, for at least fifteen minutes. The frequency of cluster headache attacks and thus the need for acute treatment can be very high. Fortunately, the Belgian social security system provides a full and lifetime reimbursement of oxygen therapy for cluster headache if the diagnosis and the need for this therapy has been certified by a neurologist, neurosurgeon or neuropsychiatrist.

Computational fluid dynamics simulation of earth air heat exchanger combined with the Quonset type greenhouse to develop a sustainable controlled environment

The current study aims to evaluate the performance of an earth air heat exchanger (EAHE) combined with a Quonset-type greenhouse in a summer climate to create a controlled environment for optimum crop development and energy efficiency. The integrated systems thermal performance and airflow patterns are analyzed using computational fluid dynamics (CFD) models. The result shows that greenhouse room air can be satisfactorily achieved in the comfortable temperature range (27–37 ℃) for plant growth by combined EAHE even during the hottest summer days. EAHE reduces greenhouse temperature with a minimum temperature gradient of 17 °C between the ambient and air at the exit of EAHEs after the heat exchanging process. It is observed from the analysis that as the flow rate of air entering into EAHE increases, the greenhouse room's temperature decreases up to 0.5 kg/s; after that, there is no significant change in temperature, which makes 0.5 kg/s the recommended flow rate for the model used in the simulation. Pressure loss is reduced in a multi-pipe EAHE system compared to a single-pipe system. This advantage can increase energy efficiency and lower operating costs in greenhouse cooling. The Quonset GiTPV system generates 29.22 kWh of electrical energy daily, making it self-sustaining.

The perspectives of UK personnel towards current killing practices for laboratory rodents

Rodents are the predominant species used for scientific research and must be humanely killed upon completion of the work. In the UK this is regulated by Schedule 1 of the Animals Scientific Procedures Act 1986, which lists permitted methodologies considered capable of humane killing, including overdose of an anaesthetic, exposure to carbon dioxide (CO2) gas, dislocation of the neck and concussion of the brain by striking the cranium. Although all are permitted, operator motivations behind method selection and individual operator preference remain unknown. The views of 219 laboratory animal personnel on institutional availability and use of Schedule 1 killing methods for laboratory rodents were obtained. Only 10% of participants reported that all four methods were available at their institution with 57.5% of respondents preferring cervical dislocation. For CO2, only 18.6% of participants reported using the recommended flow rate, while 45.5% did not know the flow rate employed. We highlight the urgent requirement for the development of quality-controlled training programmes, to improve knowledge and confidence in the selection and application of killing methods. We advocate for continuous review of killing practices to ensure best practice is reflected in legislation and achieve optimal protection of the welfare of laboratory rodents during killing.

Drilling in Gas Hydrates: Managing Gas Appearance Risks

This article provides a detailed analysis of issues related to the complications while drilling in hydrate-bearing rocks of permafrost areas. The goal of the paper is to develop recommendations for preventing gas occurrence while drilling gas hydrate deposits and to eliminate gas leakiness of the intercasing space of the well. The results of modeling the effect of drilling mud injection on the temperature field of the well are presented. It is revealed that the most significant role is played by the injection rate of drilling mud and its temperature. The recommended flow rate of the process fluid should be within 0.30–0.45 m3/s, and its temperature should not exceed 20 °C. Controlling the parameters of drilling mud and its flow rate allows for avoiding intensive gas occurrence while drilling in gas hydrates. The presence of gas hydrates may be the cause of gas leakiness of the intercasing space in the permafrost area. One of the ways to eliminate leakiness is colmatation (clogging). A method of preventing leaks in the intercasing space of the gas well is the use of colmatating solution. An aqueous solution of sodium silicate with the addition of 2% polymer is used as a colmatating composition.

Health risk assessment of exposure to benzene, toluene, ethylbenzene, and xylene (BTEX) in a composite manufacturing plant: Monte-Carlo simulations

This study aimed to assess the possible non-cancer and cancer risks associated with BTEX in a composite manufacturing plant for the first time. Air samples of BTEX were gathered from the breathing zone of participants based on the method of NIOSH 1501 using an adsorbent tube containing activated coconut charcoal and a pump at the recommended flow rate between 50 and 200 milliliters per min. After the preparation, the samples were analyzed using GC mass spectrometry. To evaluate the non-cancer and cancer risks of the pollutants, the method proposed by the United States environmental protection agency (USEPA) was applied. The mean concentrations of BTEX were found lower than the threshold limit values (TLV). The non-carcinogenic risk values of benzene, ethylbenzene, and xylene were found to be 46.00, 6.96, and 22.4 times, respectively, higher than the threshold levels set by the US EPA. Whereas the risk of toluene was lower than the acceptable limit. Moreover, the results point to a specific risk of cancer for the workers exposed to benzene and ethylbenzene in this industry, indicating a potential for 1.66 and 1.91 additional cases per 100 workers exposed to benzene and ethylbenzene, respectively.

Капельное орошение молодых плантаций виноградников в условиях Республики Крым

Purpose: to determine elements of irrigation technology for young vineyard plantations using the drip irrigation method on various types of soil in the Republic of Crimea and test them under the conditions of this region. Materials and methods. The research was carried out in the village of Pavlovka, Belogorsky district of the Republic of Crimea. The establishment of field experiments and observations were carried out using generally accepted methods for setting up and conducting field experiments. Results. As a result of the research, the water-physical properties of soils of the Republic of Crimea were analyzed and rational elements of the technology for irrigating young vineyard plantations using drip irrigation on various types of soils (limits of optimal soil moisture, dripper consumption, wetted depth, irrigation period and water application rate) were calculated. When calculating the irrigation regime for the drip irrigation method, it is necessary to take into account the wetted layer depth, the physical properties of soil, the planting pattern, the moisture contour shape, the dripper flow rate and pre-irrigation soil moisture. The elements of irrigation technology for young vineyard plantations vary significantly, for example, the recommended flow rate of drippers varies from 2–4 l/h on chernozems to 6–8 l/h on light chestnut soils and steppe solonetzes, while the duration of irrigation varies from 2–3 h on light chestnut soils up to 6–9 h on ordinary chernozems. Conclusions. When testing the results, it was found that the drip irrigation method has a positive effect on the survival rate of table grape cuttings. On average, this indicator for varieties was 98.8%. For soil and climatic conditions of the Republic of Crimea, the varieties Sport, Podarok to Irina, Baikonur and Zabava turned out to be the most responsive in terms of their morphological characteristics. During the growing season of the first year young table grapes (in a medium-dry year), 16 irrigations of 30 cubic m/ha with an irrigation rate of 480 cubic m/ha were carried out, while the total water consumption excluding the use of moisture from soil was 3740 cubic m/ha.

Python-provided algorithm for calculating oil field operation parameters for expansion drive reservoirs

The paper provides a brief description of the Python programming language, as well as its advantages and disadvantages. It considers a practical task to be solved for the oil and gas industry and ways to solve it through the Python capabilities. It proposes calculations for expansion drive oil reservoirs. Recently, much attention has been paid to computer-assisted systems aimed at processing huge amounts of expert information in the field of technical and economic appraisal of oil and gas fields. From an applied point of view, economic efficiency of an oil and gas investment project is assessed through a certain mathematical model built for calculating and analyzing project criteria based on a variety of forecast technological indicators for reservoirs produced and the field as such. Mathematical modeling in projects is challenging and demanding due to constant updating, because each field is individual, being developed in its own specific geological and technological way, with multiple options and standards for capital and operating costs. In this regard, the paper aims to create and apply smart information technology for field development, which involves collecting information on gas production wells using the Python software. The calculated dependencies and the Python software product can determine critical and recommended flow rate (with a margin of 10-20%) for wells to operate smoothly as long as sand and fluid is accumulated at the bottomhole.

Live SARS‐CoV‐2 is difficult to detect in patient aerosols

Live SARS‐CoV‐2 is difficult to detect in patient aerosols

Calibration of hydrogen Coriolis flow meters using nitrogen and air and investigation of the influence of temperature on measurement accuracy

The performance of four Coriolis flow meters designed for use in hydrogen refuelling stations was evaluated with air and nitrogen by three members of the MetroHyVe JRP consortium; NEL, METAS and CESAME EXADEBIT.A wide range of conditions were tested overall, with gas flow rates ranging from (0.05–2) kg/min and pressures ranging from (20–86) bar. The majority of tests were conducted at nominal pressures of either 20 bar or 40 bar, in order to match the density of hydrogen at 350 bar and 20 °C or 700 bar and −40 °C. For the conditions tested, pressure did not have a noticeable influence on meter performance.When the flow meters were operated at ambient temperatures and within the manufacturer's recommended flow rate ranges, errors were generally within ±1%. Errors within ±0.5% were achievable for the medium to high flow rates.The influence of temperature on meter performance was also studied, with testing under both stable and transient conditions and temperatures as low as −40 °C.When the tested flow meters were allowed sufficient time to reach thermal equilibrium with the incoming gas, temperature effects were limited. The magnitude and spread of errors increased, but errors within ±2% were achievable at moderate to high flow rates. Conversely, errors as high as 15% were observed in tests where logging began before temperatures stabilised and there was a large difference in temperature between the flow meter and the incoming gas.One of the flow meters tested with nitrogen was later installed in a hydrogen refuelling station and tested against the METAS Hydrogen Field Test Standard (HFTS). Under these conditions, errors ranged from 0.47% to 0.91%. Testing with nitrogen at the same flow rates yielded errors of −0.61% to −0.82%.

Modified Approach for Proppant Conductivity Measurement

The main goal of this study is to combine two widely used standard proppant conductivity measurement methods in order to harvest some of their advantages in case of resin-coated proppants. The available literature was studied to determine which elements can be eliminated or modified for the measurement to simplify the method and shorten its length. The proposed measurement procedure provides as short a solution as possible while maintaining suitable accuracy. An additional object of the study is to investigate the effect of different flow rates through a propped pack and find the limit of non-Darcy flow. Since higher than recommended flow rates can be utilized, less complex differential pressure measurement devices can be used. Different evaluation methods have been tried out for improved solution.

Automated systematic method for calculating the operating mode of gas wells using concentric tubing during self-pressure

The article proposes a solution to the problem of operating wells, at the bottom of which, during the production of reservoir products, fluid accumulates. It is shown that traditionally this field problem is solved by carrying out underground repairs, which creates the risk of the wells not being brought back to the initial parameters, primarily in terms of flow rate. The solution to this type of complication in the wells of the Cenomanian deposit of the Urengoy oil and gas condensate field is to transfer the wells to operation using concentric lift columns. This relatively new innovative technology allows for the removal of liquid from the bottom together with gas, thereby avoiding killing the well and its subsequent repair, as well as possible stimulating treatments to restore the necessary flow. It is shown that by calculating the dependencies and the software package it is possible to determine the critical and recommended flow rates for well operation without complications.

Development of a static test apparatus for evaluating the performance of three PM2.5 separators commonly used in China

PM2.5 separator directly affects the accuracy of PM2.5 sampling. The specification testing and evaluation for PM2.5 separator is particularly important, especially under China's wide variation of terrain and climate. In this study, first a static test apparatus based on polydisperse aerosol was established and calibrated to evaluate the performance of the PM2.5 separators. A uniform mixing chamber was developed to make particles mix completely. The aerosol concentration relative standard deviations of three test points at the same horizontal chamber position were less than 0.57%, and the particle size distribution obeyed logarithmic normal distribution with an R2 of 0.996. The flow rate deviation between the measurement and the set point flow rate agreed to within ±1.0% in the range of −40 to 50°C. Secondly, the separation, flow and loading characteristics of three cyclone separators (VSCC-A, SCC-A and SCC112) were evaluated using this system. The results showed that the 50% cutoff sizes (D50) of the three cyclones were 2.48, 2.47 and 2.44 μm when worked at the manufacturer's recommended flow rates, respectively. The geometric standard deviation (GSD) of the capture efficiency of VSCC-A was 1.23, showed a slightly sharper than SCC-A (GSD =1.27), while the SCC112 did not meet the relevant indicator (GSD = 1.2 ± 0.1) with a GSD = 1.44. The flow rate and loading test had a great effect on D50, while the GSD remained almost the same as before. In addition, the maintenance frequency under different air pollution conditions of the cyclones was summarized according to the loading test.

Laboratory comparison of new high flow rate respirable size-selective sampler

A newly developed high flow rate respirable size-selective cyclone sampler (GK4.162—also known as the Respirable Air Sampling Cyclone Aluminum Large (RASCAL)) was calibrated to determine its optimum operating flow rate. The Health and Safety Laboratory in the United Kingdom and two laboratories from the National Institute for Occupational Safety and Health in the United States conducted experiments using two different methods: (1) polydisperse aerosol and time-of-flight direct reading instrument (Aerodynamic Particle Sizer (APS)) and (2) monodisperse aerosol and APS. The measured performance data for the cyclone was assessed against the international respirable convention using the bias map approach. Although the GK4.162 cyclone was tested using different aerosols and detection methods, the results from the three laboratories were generally similar. The recommended flow rate based on the agreement of results from the laboratories was 9.0 L/min.

A novel hybrid energy system combined with solar-road and soil-regenerator: Sensitivity analysis and optimization

Abstract To reduce the dependency of fossil fuels and greenhouse effect, the authors have proposed a novel solar-road and soil-regenerator hybrid energy system (SRSRHES), which utilizes a combination of Photovoltaic-Thermal (PVT) and soil heat storage technologies on the roadways. Design parameters and meteorological conditions affect the thermal storage performance of SRSRHES, which directly influences its annual performance and cost-effectiveness. Therefore, the study investigated the influence of flow rate, soil thermal properties, collector area, and borehole depth on electrical and thermal performance in three different cities with a numerical method to realize rational configuration of design parameters for the system. The results indicated that the recommended flow rates are 0.5, 0.3, and 0.3 kg/s in Beijing, Harbin, and Barkam respectively; Overall energy efficiency for different soils is different that is increased in the order of clay, sandy soil, sandstone, limestone, and granite. Collector area exerts a positive effect on total energy generation, but has a negative effect on overall energy efficiency. Borehole depth has a positive effect on both total energy generation and overall energy efficiency; Furthermore, the influence of various parameters on power generation performance is less than thermal storage performance, and overall energy efficiency mainly depend on thermal storage performance.

A model for oxygen conservation associated with titration during pediatric oxygen therapy.

BackgroundContinuous oxygen treatment is essential for managing children with hypoxemia, but access to oxygen in low-resource countries remains problematic. Given the high burden of pneumonia in these countries and the fact that flow can be gradually reduced as therapy progresses, oxygen conservation through routine titration warrants exploration.AimTo determine the amount of oxygen saved via titration during oxygen therapy for children with hypoxemic pneumonia.MethodsBased on published clinical data, we developed a model of oxygen flow rates needed to manage hypoxemia, assuming recommended flow rate at start of therapy, and comparing total oxygen used with routine titration every 3 minutes or once every 24 hours versus no titration.ResultsTitration every 3 minutes or every 24 hours provided oxygen savings estimated at 11.7% ± 5.1% and 8.1% ± 5.1% (average ± standard error of the mean, n = 3), respectively. For every 100 patients, 44 or 30 kiloliters would be saved—equivalent to 733 or 500 hours at 1 liter per minute.ConclusionsOngoing titration can conserve oxygen, even performed once-daily. While clinical validation is necessary, these findings could provide incentive for the routine use of pulse oximeters for patient management, as well as further development of automated systems.

Assessment of the quality, effectiveness, and acceptability of ceramic water filters in Tanzania

Globally, approximately two billion people drink contaminated water. Use of household water treatment (HWT) methods, such as locally manufactured ceramic filters, reduces the diarrheal disease burden associated with unclean water. We evaluated the quality, effectiveness, and acceptability of ceramic filters in two communities in Arusha, Tanzania, by conducting: 1) baseline household surveys with 50 families; 2) filter flow rate testing; 3) filter distribution with training sessions; 4) follow-up surveys at 2, 4, and 6 weeks after distribution; and 5) project end focus group discussions. We tested Escherichia coli (E. coli) and turbidity at baseline and the first two follow-ups. We found: 1) filter quality was low, as only 46% of filters met recommended flow rate guidelines and 18% of filters broke during the 6-week study; 2) filter effectiveness was moderate, with 8% and 35% of filters effectively reducing E. coli to <1 CFU/100 mL and <10 CFU/100 mL, respectively, at follow-ups; and, 3) filter acceptability was high, with 94% overall satisfaction and 96–100% reported use in the previous day. These results highlight the importance of mixed methods research as HWT product quality, effectiveness, and acceptability all impact product efficacy, and the need for quality assurance/quality control and certification schemes for locally manufactured HWT products.

The effect of carbon dioxide flow rate on the euthanasia of laboratory mice

Laboratory rodents are commonly euthanized by exposure to gradually increasing concentrations of carbon dioxide (CO2). Current recommended flow rates range between 10 and 30% chamber vol/min and result in insensibility before exposure to painful concentrations (<40%). However, this method causes dyspnea, indicated by deep, rapid breathing. In humans dyspnea is associated with a negative affective experience. Sensations of dyspnea may explain why rodents find CO2 concentrations >3% aversive. This study aimed to assess the effect of CO2 flow rates on time between the onset of dyspnea and various measures of insensibility (recumbency, loss of the righting reflex and loss of the pedal withdrawal reflex) to identify flow rates that minimize the potential experience of dyspnea. The results of this study indicate that a flow rate of 50% chamber vol/min, while holding the CO2 cage concentration just below 40%, minimizes the interval between the onset of labored breathing and recumbency. Using a 50% flow rate this interval averaged (± SE) 30.3 ± 2.9 s versus 49.7 ± 2.9 s at 20% chamber vol/min (F3,22 = 7.83, P = 0.0013). Similarly, the interval between the onset of labored breathing and loss of the righting reflex averaged 38.2 ± 2.4 s at a flow rate of 50% versus 59.2 ± 2.4 s at 20% chamber vol/min of CO2 (F3,22 = 13.62, P < 0.0001). We conclude that higher flow rates reduce the duration of dyspnea, but even at the highest flow rate mice experience more than 30 s between the onset of dyspnea and the most conservative estimate of insensibility.

A practical approach to the theoretical models to calculate NO parameters of the respiratory system

Expired nitric oxide (NO) is used as a biomarker in different respiratory diseases. The recommended flow rate of 50 mL s−1 (FENO0.05) does not reveal from where in the lung NO production originated. Theoretical models of NO transfer from the respiratory system, linear or nonlinear approaches, have therefore been developed and applied. These models can estimate NO from distal lung (alveolar NO) and airways (bronchial flux). The aim of this study was to show the limitation in exhaled flow rate for the theoretical models of NO production in the respiratory system, linear and nonlinear models. Subjects (n = 32) exhaled at eight different flow rates between 10–350 mL s−1 for the theoretical protocols. Additional subjects (n = 32) exhaled at tree flow rates (20, 100 and 350 mL s−1) for the clinical protocol. When alveolar NO is calculated using high flow rates with the linear model, correction for axial back diffusion becomes negligible, –0.04 ppb and bronchial flux enhanced by 1.27. With Högman and Meriläinen algorithm (nonlinear model) the corrections factors can be understood to be embedded, and the flow rates to be used are ≤20, 100 and ≥350 mL s−1. Applying these flow rates in a clinical setting any FENO can be calculated necessitating fewer exhalations. Hence, measured FENO0.05 12.9 (7.2–18.7) ppb and calculated 12.9 (6.8–18.7) ppb. In conclusion, the only possibility to avoid inconsistencies between research groups is to use the measured NO values as such in modelling, and apply tight quality control to accuracies in both NO concentration and exhaled flow measurements.