Characteristic Diameter Research Articles

Evaluation of the performances of two artisanal incubators on the hatching of broiler breeding eggs (Yamoussoukro, Ivory Coast)

To improve poultry production in Ivory Coast, a study was carried out in the commune of Yamoussoukro with 481 eggs from two breeds of meat breeders (Rouge Flesh and Kuroilers) which were collected during their reproduction. These eggs were distributed between three incubators, two of which were artisanal (Incubator 1 and Incubator 2) and one was industrially manufactured (Incubator 3), after determining their characteristics (weight, length and diameter). Incubation parameters were measured twice a day (at 8 a.m. and 5 p.m.) and brooding parameters such as apparent hatching rate, actual hatching rate, mortality rate embryonic and shell mortality rate were estimated. The results showed a significant difference (p<0.05) in the average weight of Rufous Flesh eggs (51.54±5.3 g) compared to Kuroiler eggs (50.02±5.54 g). The average temperatures recorded (37.40±0.55 °C for incubator 1; 37.58±0.49 °C for incubator 2 and 37.59±0.53 °C for incubator 3) were significantly identical (p>0.05). As for the hygrometry, that of incubator 3 (59.98±6.02 %) was significantly higher (p<0.05) than that of incubator 1 (54.58±1.80 %) and from incubator 2 (54.86±3.26 %). The actual hatching rate of incubator 1 (85.76±14.21 %) was significantly higher (p<0.05) than that of incubator 2 (70.85±14.48 %) and identical (p>0.05) to that of incubator 3 (73.95±16.45 %). Concerning the shell mortality rate, incubator 1 (1.03±2.18 %) recorded a significantly lower rate (p<0.05) than that of incubator 3 (7.43±4.56 %) and significantly identical (p>0.05) to that of incubator 2 (2.52±6.35 %). From this study, the artisanal incubators 1 and 2 meet the criteria for brooding and deserve to be used.

Comprehensive analysis of particle emissions from miniature turbojet engine

Emission of particulate matter from jet engines contribute to deterioration of air quality in the vicinty of the airports and to formation of contrails in higher layers of the atmosphere. This article presents the results of the measurements of particle emissions from a miniature jet engine GTM-120 fueled conventional aviation fuel Jet A-1. Analysis of particle size distribution, number, mass and volume emission indexes has been made, as well as the analysis of the emission intenisty and mass emission rate. Obtained results were related to LTO cycle phases. The results shows, that the particle number concentration was the lowest for low engine loads, with characteristic diameter of 69.8 nm and the particles concentration of 7.7 x 106 particles/cm3. For thrust increase, the characteristic diameter is smaller, and the particles distribution is no longer single-mode. The highest particles concentration for cm3 is for 100% thrust and is equal to 1.55 x 107 particles, with characteristic diameter of 34 nm.

Influence of in-situ lunar temperature on the pore structure and solid phases of alkali-activated lunar regolith simulant

The construction of extraterrestrial bases has become an indispensable step in the active exploration of deep space. In this study, alkali-activated lunar regolith simulant (AALRS) activated by sodium hydroxide (SH) and sodium silicate (SS) were prepared and then cured at various lunar temperatures. The compressive strength was tested, and the pore structure characteristics were characterized using mercury intrusion porosimetry (MIP), followed by further in-depth quantitative analysis through fractal theory. The solid phases were characterized using thermogravimetry analysis (TGA) and scanning electron microscopy (SEM). It is found that all the fractal curves are divided into three regions, and the fractal dimensions in all regions are between 2 and 3, suggesting the pores of AALRS paste always have self-similar physical significance. The fractal dimension D1 of the small pore is the largest, followed by fractal dimension D3 of the great pore and fractal dimension D2 of the middle pore. The increase in modulus and temperature leads to an increase in the pore surface area, fractal dimension, amount of N-A-S-H gel and compressive strength and a decrease in total pore volume and characteristic pore diameter, which is mainly attributed to the nucleation effect of soluble Si. The turning pore diameter at the micrometer scale and excessive porosity of AALRS paste, which is distinctly different from that of common cementitious materials, demonstrates looser pore structure of AALRS paste. Based on these results, the influence mechanism of in-situ lunar temperature on the performance of AALRS paste is profoundly discussed and elucidated, which provides a deep understanding of designing and tailoring the various properties of AALRS material.

The modelling error in multi-dimensional time-dependent solute transport models

Starting from full-dimensional models of solute transport, we derive and analyze multi-dimensional models of time-dependent convection, diffusion, and exchange in and around pulsating vascular and perivascular networks. These models are widely applicable for modelling transport in vascularized tissue, brain perivascular spaces, vascular plants and similar environments. We show the existence and uniqueness of solutions to both the full- and the multi-dimensional equations under suitable assumptions on the domain velocity. Moreover, we quantify the associated modelling errors by establishing a-priori estimates in evolving Bochner spaces. In particular, we show that the modelling error decreases with the characteristic vessel diameter and thus vanishes for infinitely slender vessels. Numerical tests in idealized geometries corroborate and extend upon our theoretical findings.

Study on the microscopic characteristics of pentanol/highly active fuel spray based on high-speed droplet tracking velocimetry technology

Pentanol blending with highly reactive fuels for internal combustion engines holds considerable promise. The atomization of sprays closely influences the efficiency and combustion characteristics of the system. Based on Particle Tracking Velocimetry and high-speed shadow imaging technology, we propose a method termed High-speed Droplet Tracking Velocimetry for analyzing spray particle size. Prior to conducting our study, we validated the reliability of High-speed Droplet Tracking Velocimetry through comparisons with the Malvern and Phase Doppler methods. This study utilized long working distance micro high-speed shadow imaging technology in a visualized constant volume combustion chamber to investigate the spray micro-characteristics of pentanol blended with highly reactive fuels, including Fatty Acid Methyl Ester, Hydrogenated Catalytic Biodiesel, and Diesel. The results indicate that under all operating conditions, the droplets of P20H80 (the volume fraction of 20 % n-pentanol mixed with 80 % Hydrogenated Catalytic Biodiesel) are smaller and more uniformly distributed, demonstrating the minimum Sauter Mean Diameter, characteristic diameter, and width of droplet size distribution. The droplet velocities of P20H80 are the lowest, followed by P20Di80 (the volume fraction of 20 % n-pentanol mixed with 80 % Diesel), and P20B80 (the volume fraction of 20 % n-pentanol mixed with 80 % Fatty Acid Methyl Ester) exhibits the highest velocities. These velocity differences among the three fuels generally remain within 10 %-20 % across various injection pressures. P20Di80 shows the highest Reynolds and Weber numbers, followed by P20H80, with P20B80 having the smallest values due to its intermediate physical properties. The gaps between each fuel type range from 20 % to 30 %.

Associations among the largest follicle, preovulatory estradiol concentrations, and predominant vaginal epithelial cells at the completion of hormonal ovarian stimulation for fixed-time artificial insemination in goats.

The objective of the present study was to investigate the association among the largest follicle (LF), preovulatory estradiol (E2), and predominant vaginal epithelial cell at the completion of hormonal ovarian stimulation for fixed-time artificial insemination (FTAI) in goats. Thirty-seven crossbred Boer does received gonadotropin-releasing hormone (GnRH) and intravaginal progesterone (P4)-releasing devices (day 0). On day 5, P4 devices were removed and does received prostaglandin F2α and equine chorionic gonadotrophin. On day 7, does received GnRH, and FTAI was undertaken. On day 7, does were divided into three groups, i.e. small-sized (3-3.9 mm; n = 5), medium-sized (4-4.9 mm; n = 8), and large-sized (≥5 mm; n = 24) according to the diameter of the ovarian LF; follicular characteristics (number and diameter) were identified, and blood samples and vaginal smears were collected. The average diameters of total antral follicles and LF and the percentage of superficial cell were greatest in large-sized LF does (p < .01). The average diameters of total antral follicle (r = .68) and LF (r = .71), number of preovulatory follicle (r = .58), and plasma E2 concentrations (r = .61) were positively correlated with the percentage of superficial cells (p < .01). The likelihood of a pregnancy outcome after the FTAI increased by 13.71 times in does with a greater average diameter of antral follicle, 14.18 times with emergence of a large preovulatory follicle, and 36.83 times with a higher percentage of vaginal superficial cells (p < .01). It was concluded that there is a relationship between the cell types of the vaginal epithelium, the diameters of the largest ovarian follicles, and the concentration of E2 in goats subjected to FTAI protocols.

Unification of particle size analysis results, part 1 − comparison of particle size distribution functions obtained by various measurement methods

This article concerns comparing the grain size distribution functions of mineral powder samples and analyzes errors obtained by various measurement methods. The research used three standard and currently most frequently used methods: sieve analysis, laser diffraction analysis and vision analysis. The most important research, from the point of view of unification of results, consisted in performing precise analyses of the grain size of mineral powders (fly ash, gneiss, quartz sand and Cu ore) in various grain classes. The measurement techniques used in the research and issues related to measurement analytics were characterized. The distribution functions of the grain size distributions of the tested material samples were obtained by different measurement methods and the measurement errors were compared. Using the coefficient of variation CV calculated for characteristic particle diameters, the accuracy of measurements made using various methods was analyzed. It has been shown that different particle size measurement techniques give significantly different particle size distributions for the same material, with the grain size distribution of the measured samples having a greater impact on the results than the material itself. The lowest values of the coefficients of variation were obtained for wet sieve analysis and the highest for laser diffraction. Reliable data informing about grain size distributions were generated for further model calculations necessary to standardize the results between measurement methods.

Comparison of devices used for continuous production of emulsions: Droplet diameter, energy efficiency and capacity

Liquid-liquid emulsions are used in various sectors, including food, health care, personal care, home care and nutrition. There is an increasing need for developing equipment and devices for producing emulsions with desired drop size distribution (DSD) in a continuous mode of operation to fulfil market demands. In this work, we experimentally investigated droplet size distributions of emulsions made using selected cavitation-based emulsion producing devices operated in a continuous mode. Emulsion production devices considered in this work are wet mill, Soldo cavitator, Dynaflow cavitator and different scales of vortex based hydrodynamic cavitation devices. The continuous emulsion production experiments were performed for generating 5 % rapeseed oil-in-water emulsions using different devices. Performance of different emulsion production devices based on energy efficiency of emulsification (η), energy consumption per kilogram of emulsion (E), interfacial area created per unit energy consumption (Anet)P, Sauter mean diameter (d32), other characteristic diameters (D10,D50,D90), and drop size distribution (DSD) was compared. Among all the devices, vortex based hydrodynamic cavitation (HC) devices showed excellent performance in terms of lower d32 and DSD with low E and high η. The smallest scale of vortex-based HC device exhibited the highest efficiency (∼0.16 % at E = 2.6 kJ/kg) over the entire range of E compared to the other devices considered in this study. The presented data and analysis will be useful for selection of emulsion producing devices for desired emulsion characteristics and production capacity.

Basic performance, cavitation and runaway investigations of a high specific speed Francis turbine with emphasis on cavitation analysis: A case study

The paper presents comprehensive experimental research on a high specific speed model Francis turbine with a characteristic runner diameter of 250 mm under the head of 12 m. Essentially, the turbine was designed for use at heads between 10 and 50 m, which are typical for installations with low specific speed Kaplan turbines. The basic performance, cavitation and runaway characteristics of the machine, which were determined as a result of the work, are quite rarely available in the literature in the case of high specific speed Francis turbines. The turbine achieved the maximum efficiency of 91%, kinematic specific speed of 82, and relatively wide operation range, so that it can be attractive as an alternative to the low specific speed Kaplan, semi-Kaplan or propeller turbines.In result of the basic laboratory tests, the performance characteristics of the machine operation in a wide range of guide vane opening angles between 9° and 36° as well as the shell efficiency characteristics were determined. On the characteristics plotted vs. rotational speed, the saddle effect was identified for the guide vane opening angles with values greater than the optimal one (22°). During the operation of the machine in the area of saddles, the change in the flow rate took quite surprising patterns. The share of the turbine thrust torque in the total torque was also determined, the characteristics of which are also burdened with a similar saddle effect.In the case of cavitation tests, a multi-aspect approach to cavitation diagnostics was used to characterize the cavitation phenomenon from the viewpoint of various criteria. Following this approach, the signals of the draft tube wall acceleration, acoustic emission at the draft tube cone upper flange, and pressure fluctuations inside the draft tube were used. The determined cavitation characteristics indicate little cavitation susceptibility of the Francis turbine blade system, despite the presented turbine having been designed to operate at higher flow rates than the classic high head Francis turbines with long interblade channels. The cavitating flow in the draft tube, directly below the runner, was also visualized during the cavitation tests. The paper presents the results of visualization for all cavitation states at five selected settings of the guide vane opening angle (two states in Partial Load, two states in High Load area and one state in the Best Efficiency Point), thanks to which it was possible to track the development of vortices during pressure reduction in the flow system.The runaway coefficient was determined as a result of the runaway tests. The value of 1.497 was reached at the optimum guide vane opening angle.Additionally, the work also presents in detail the efficiency scale effects to be expected at prototype turbines, i.e. those intended for operation at a higher head and with larger runner diameters. The efficiency of the machine with a runner diameter of 1.5 m and working at a head of 50 m reaches ∼93%. The influence of water viscosity on the change in efficiency of the prototype turbine is also shown.The presented methodology can be used for the proper selection of turbines intended for hydropower plants and for the proper installation of the runner in respect to the tailwater level in order to avoid the phenomenon of cavitation erosion.

Transformation of Bi4Cl2S5 into sub-10 nm Bi2O2CO3 nanowires for electrochemical reduction of CO2

The development of highly efficient catalysts for the selective electrochemical reduction reaction of CO2 (eCO2RR) to high-valued formate remains a challenge in achieving carbon neutrality and renewable energy conversion. In this study, ultrathin Bi4Cl2S5 nanowires, synthesized using different branched-chain thiols as sulfur sources, were reported for the first time as precatalysts for eCO2RR to formate. Systematic material characterization demonstrated that Bi4Cl2S5 can undergo in-situ evolution into Bi2O2CO3 nanowires, serving as the genuine electrocatalyst for eCO2RR. Through the fine-tuning of ligands during the synthesis of Bi4Cl2S5 nanowires, the optimized Bi4Cl2S5-derived Bi2O2CO3 nanowires exhibited a maximum formate Faradaic efficiency (FEformate) of 95.3 % in eCO2RR using a traditional H-cell, surpassing other prepared samples. Furthermore, an FEformate of over 92.9 % was achieved in a wide potential window of 500 mV, and high performance was maintained over 20 h. This outstanding performance is attributed to the high intrinsic activity, accelerated charge transfer, and the large electrochemical active surface area associated with the characteristic sub-10 nm diameter nanowire structure. Moreover, density function theory calculations further revealed that Bi2O2CO3 can reduce the energy barriers for the formation of *OCHO intermediate and bolster formate production. Our work provides a novel synthesis strategy for excellent Bi-based catalysts in electrocatalysis.

Determination of prickle effect detection thresholds in Llama fiber knitted fabrics

The study delves into determining the detection thresholds for the prickle effect in Llama fiber knitted fabrics, crucial for fabric acceptability assessment, by consumers of garments made from natural fibers. Employing standard evaluation methods involving moistened skin and perception scoring, coupled with the identification of objectionable (coarse) fiber content as a pivotal variable, the research using 41-invited panelist elucidates the intricate interplay between fiber characteristics (diameter) and prickle perception. Despite efforts to mitigate hairiness through finishing processes, the study unveils the nuanced impact of fiber protrusion on the prickle effect, necessitating a comprehensive evaluation approach. Through pairwise comparisons and perception scales, the study unveils strong associations between prickle perception and expression degrees, reaffirming panelists' sensitivity in detecting subtle variations. Statistical analyses underscore significant differences in coarse fiber content and diameter between paired samples, further corroborating panelists' discernment. It can be clearly concluded, from this analysis, the prickle effect detection thresholds in llama fiber fabrics range from 2.36 to 2.42% in coarse fiber differences and from 0.11 to 1.63 microns in fiber diameter difference, in the 95% of the tested cases or more probability. In conclusion, the study delineates critical thresholds (2.36%) for prickle detection in Llama fiber fabrics, offering invaluable insights for fabric evaluation and refinement processes, and emphasizing the heightened sensitivity of finished fabric samples in prickle perception.

Radiographic bone loss around dental implants: a large-cohort, long-term follow-up revealing prevalence and predictive factors.

This retrospective study analyzed radiographic bone levels of 10,871 dental implants in a cohort of 4,247 patients over a 22-year period. The objectives of the study were to assess and explore risk factors associated with the radiographic bone level of dental implants. A longitudinal observational cohort study based on data collected from 1995 to 2019 was conducted on implants placed by a single periodontist. Inclusion criteria included both partially and fully edentulous sites. Exclusion criteria were patients who were considered ASA 3 or greater. Information on medical and dental status prior to implant placement such as diabetes and smoking were included in the analysis. Implant factors such as the implant characteristics (length and diameter) and surgical site were recorded. The outcome assessed was the prevalence of bone loss around implants and any associative factors related to the bone loss. Overall, dental implants lost an average of 0.05 ± 0.38 mm of bone 2 to 3 years after placement and 0.21 ± 0.64 mm 8 years after placement. The soft tissue condition was evaluated using the Implant Mucosal Index (IMI), and bone loss around dental implants was significantly higher when bleeding on probing was multi-point and moderate, multi-point and profuse, and when infection with suppuration was recorded. The mean difference in bone level between smokers and nonsmokers was 0.26 mm (P < .01) over a 4-year period. A mean difference of 0.10 mm (P = .04) in bone loss over 4 years was found between those with an autoimmune disease compared to those without. The diameter of the implant and immediate loading of the dental implant did not influence the radiographic bone levels over time. This large dataset of dental implants highlights predictive risk factors for bone loss around dental implants and the impact these risk factors have on the implant bone level. Consideration of these risk factors by both the dental team and the patient prior to dental implant placement will promote success of the treatment.

Estimating droplet size distribution of emulsions using turbidity measurements: A soft sensor based on artificial neural network

Ability to characterise droplet size distribution (DSD) of emulsions in real-time is essential for on-demand production of customised emulsions. In this work, for the first time, we demonstrate a possibility of estimating full DSD of oil in water emulsions from turbidity measurements using a single wavelength light source. We used recently published data of DSD and turbidity measurements of rapeseed oil in water emulsions (oil volume fractions of 0.15, 0.3 and 0.45) produced with vortex based hydrodynamic cavitation device. Measured DSDs are represented by weighted sum of three log-normal distributions. We developed an approach and a methodology based on artificial neural network (ANN) to estimate DSD from a single measurement of turbidity. A mathematical model is developed to simulate measured turbidity profiles using the known DSDs. The validated model was then used to generate simulated data of turbidity and oil volume fraction pairs (105 pairs). This synthetic data was used to train ANN which used turbidity and volume fraction as input and eight parameters of DSD as output. The developed ANN was able to capture the experimentally measured characteristic diameters and DSDs very well for three oil volume fractions and four different number of passes. The presented methodology and results will be useful for developing an in-line soft sensor based on turbidity measurements for real time estimation of full DSDs of emulsions.

Experimental investigation of rectangular nozzle aspect ratio effects on high-pressure helium leakage characteristics

High-pressure hydrogen leakage is one of the bottlenecks restricting the development of the hydrogen energy industry. In this study, a high-pressure helium leakage experimental system with stable pressure was built to research the influence of aspect ratio on concentration decay rate and mass flow rate. Similar to the circular nozzle, the centerline helium concentration of the rectangular jet is also inversely proportional to the distance from the nozzle. For the rectangular nozzles with aspect ratio of 1–4, the helium concentration decay rate is consistent with the circular nozzle when the leakage pressure is lower than 6.5 MPa. However, the decay rate is obviously larger for rectangular nozzles with aspect ratio of 10 when the leakage pressure is greater than 5.0 MPa. The aspect ratio has a greater influence on the flow coefficient, which increases with the aspect ratio under the same leakage pressure. To comprehensively consider the effects of nozzle size and shape, a weighted characteristic diameter of equivalent diameter and rectangular width, dc=αde+1−αdw, was proposed in this study. The results indicate that the equivalent diameter has greater impact on the centerline concentration decay rate, while the width of nozzles has substantial influence on the flow coefficient.

ON THE PERFECTION OF THE APPROACH TO THE FORMATION OF A PROGRAM FOR INCREASING THE RELIABILITY OF FIELD PIPELINES IN OC ROSNEFT

The article describes an approach for ranking and selecting field pipelines based on the total cost of ownership of the facility for the purpose of timely repairs and minimization of accidents, as well as its software implementation. The principle of the proposed approach is to apply a technical and economic model of the total cost of ownership of a pipeline, which takes into account the costs of maintaining the pipeline over a long period of time, which include the costs of pipeline maintenance activities, pipeline failures and replacement of pipeline sections. This model allows determining which replacement year corresponds to the minimum accumulated maintenance costs, by varying the year of pipeline replacement from the start of operations to the planning horizon. The model also allows to take into account the impact of operational technological measures on the cost of pipeline ownership and the selection of the optimal year of repair.In order to take into account the level of pipeline accidents in the process of operation on the basis of operational data, a mathematical probabilistic model based on the Weibull distribution was developed. The mathematical model allows to take into account for each pipeline the influence of technical characteristics (diameter, length, wall thickness, material, coating, design features), operating conditions (type of pumped medium, technological mode of pipeline operation) and information on inspection and diagnostics. The accuracy of failure prediction using this model is at least 90 %.The approach to the formation of programs to improve the reliability of field pipelines with regard to optimal repair periods based on the total cost of ownership model is described, taking into account various objectives and constraints, among which the main ones are:- required achievable level of accidents;- acceptable amounts of financing for re-pairs;- permissible physical volumes of repairs along the length.The approach to forming reliability improvement programs described in this article has been implemented in Rosneft's corporate software system RN-SM. The implementation of this software package in production activities is being implemented in 2023–2024.

Dual-wavelength lasing at ∼1.2 μm and ∼2.0 μm in a Ho3+-doped fluoroaluminate glass microsphere

This study presents the experimental realization of a microsphere laser resonator designed to operate within the approximate wavelength range of 1.2 μm and 2.0 μm. This resonator, employing a Ho3+-doped fluoroaluminate glass microsphere, was stimulated by a 1150 nm laser, marking the first demonstration of its kind. The observed laser emissions at ∼1.2 μm and ∼2.0 μm were ascribed to the transitions of Ho3+ ions, specifically 5I6 → 5I8 and 5I7 → 5I8, respectively. The fabrication of the microsphere, possessing a characteristic diameter of approximately 50 μm, entailed the controlled melting of a fluoroaluminate glass filament through the application of a focused CO2 laser beam. Concurrently, a tapered fiber with a waist diameter of ∼2 μm was created by subjecting a standard silica single-mode fiber to a process of controlled heating and stretching. The findings of this investigation suggest promising prospects for the development of multi-wavelength lasers utilizing fluoroaluminate glass microspheres, particularly in intricate environmental settings.

Impacts of Rainfall Characteristics and Slope on Splash Detachment and Transport of Loess Soil

To identify the key parameters and develop accurate experimental models of detachment and transport, splash detachment and transport of loess soil were investigated in relation to the rainfall characteristics and slope. The experiment was conducted under 25 combinations of five rainfall intensities (60, 84, 108, 132 and 156 mm h−1) and five slope gradients (0°, 5°, 10°, 15° and 20°), using a custom splash pan. Raindrop characteristics (diameter, velocity and kinetics) and splash mass were measured in downslope and upslope. The results indicated that rainfall intensity and slope contributed 94.77% and 0.46%, respectively, to the detachment rate, and 24.39% and 67.82%, respectively, to the transport rate. From a holistic viewpoint, the positive effect of slope became more visible on the detachment rate when the rainfall intensity exceeded 108 mm h−1, and on the transport rate when the slope exceeded 15°. Based on the rainfall simulator in this study, the rainfall kinetic energy (KE, J), raindrop median particle size (D50, mm) and raindrop terminal velocity (V, m s−1) all increased with increasing rainfall intensity (I) within the 60~108 mm h−1 range but decreased with increasing rainfall intensity within the 132~156 mm h−1 range. The rainfall intensity and raindrop characteristics (D50/V/KE) are the key parameters of splash detachment (Dr, g·m−2 min−1), and three detachment models were developed: (1) Dr = 0.1153 I1.09D500.79 (R2 = 0.99, NSE = 0.98, p &lt; 0.01); (2) Dr = 0.0162 I1.11V1.22 (R2 = 0.99, NSE = 0.99, p &lt; 0.01); and (3) Dr = 0.0813 I1.10KE0.18 (R2 = 0.99, NSE = 0.99, p &lt; 0.01). The rainfall intensity and slope are the key parameters for splash transport (Tr, g·m−2 min−1), and the developed transport models could be expressed as: (1) Tr = 0.00657 I1.343S0.116 (R2 = 0.914, NSE = 0.874, p &lt; 0.01) (slopes of 0°, 5° and 10°) and (2) Tr = 0.00218 I1.165S1.033 (R2 = 0.986, NSE = 0.986, p &lt; 0.01) (slopes of 15° and 20°). The results of this study could enhance the understanding of soil splash detachment and transport on loess slopes.

Probability model for gas–liquid annular flow in dynamic equilibrium among the processes of atomization, deposition, breakup, and coalescence

In this paper, an improved probability model is introduced to provide a more comprehensive prediction of annular flow. Unlike previous work, which did not consider atomization and deposition, as well as breakup and coalescence, simultaneously, the improved model integrates all four processes into its framework. The mechanisms of these processes are described in detail by the present model. When annular flow is fully developed, the four processes reach dynamic equilibrium. A numerical program is compiled based on the influence of the four processes on the droplets. Five important parameters, including the droplet-diameter probability density distribution, characteristic droplet diameters, entrainment ratio, liquid film thickness, and interfacial shear-stress coefficient, are calculated when the annular flow is in dynamic equilibrium. The validity and accuracy of the improved model are assessed by comparison with 377 cases from 12 experiments. For most cases used to validate the predicted droplet-diameter probability density distribution, the prediction curves closely match the experimental data. The mean absolute percentage errors (MAPEs) for the two experiments used to validate the predicted characteristic droplet diameters are 20.74% and 24.04%, respectively. Additionally, the mean MAPEs of the entrainment ratio, liquid film thickness, and interfacial shear-stress coefficient are found to be 34.11%, 20.60%, and 27.28%, respectively. This demonstrates the effectiveness and reliability of the improved probability model in predicting annular flow.

Optimal valve closing law for improved water hammer control: a case from a water supply pipeline in Guelma, Algeria

Abstract Finding the most suitable closing law is essential to decrease the shock wave pressure caused by transient flow and minimize the potential damage to equipment. The closure of a valve can occur instantly, rapidly, or gradually, and the appropriate law can be convex, linear, or concave, depending on various factors. These factors include the pipe's characteristics (type, diameter, roughness, and length), the conveyed fluid (nature and temperature), and operating conditions (pressure and flow rate). Other factors that receive less attention, such as the duration of slow closure and the impact of soil load on the pipe, are also considered in this study. The main focus of this article is to investigate how the optimal law evolves based on the time it takes for a valve to gradually close, specifically in the case of a valve located at the end of an underground gravity supply pipe. The findings reveal that when the slow closure time (t) exceeds 0.50 times the return period (t4), the exponent of the optimal law becomes a damped periodic function. Each closure time corresponds to a unique optimal law, and as the valve closure time increases, the range of optimal laws becomes narrower.

Application of the Global Uncertainty and Sensitivity Analysis to assess the importance of deadwood characteristics for forest biodiversity

AbstractData acquisition for sustainable forest management has focused on obtaining high quality information to estimate biomass. Improving the quality of non-timber sustainability indicators, like deadwood volume, has been a minor interest. To explore how inventory approaches could be improved, we applied a Global Uncertainty and Sensitivity Analysis (GUSA) to evaluate which factors propagate more errors in deadwood modelling and how better data collection can minimize them. The impact of uncertainty on deadwood characteristics (diameter, collapse ratio, decay class, tree species, and position) was explored under stakeholders´ preferences, management actions, and climate change scenarios. GUSA showed that removing the prediction error in deadwood tree species and diameter would alter the most the total uncertainty in deadwood volume. We found that assessment of high deadwood volume was less uncertain for the scenarios where small deadwood items were left decaying on the forest floor (BAU) and for high-end climate change scenario (RCP8.5) which resulted in lower deadwood accumulation in forest stands and therefore also in lower likelihood of erroneous estimates. Reduced uncertainty in tree species and diameter class will elevate the certainty of deadwood volume to a similar level achieved in living biomass estimation. Our uncertainty and sensitivity analysis was successful in ranking factors propagating errors in estimate of deadwood and identified a strategy to minimize uncertainty in predicting deadwood characteristics. The estimation of uncertainty in deadwood levels under the scenarios developed in our study can help decision makers to evaluate risk of decreasing deadwood value for biodiversity conservation and climate change mitigation.