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1
Beck, S. M., H. Haider, and R. F. Boucher. "Transmission Line Modelling of Simulated Drill Strings Undergoing Water-Hammer." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 209, no. 6 (November 1995): 419–27. http://dx.doi.org/10.1243/pime_proc_1995_209_172_02.
Повний текст джерелаАнотація:
Drill strings and oil production lines are examples of fluid systems for which time-dependent (dynamic) as well as steady state (static) analysis is increasingly needed. These systems are difficult and expensive to instrument and test experimentally. Developments of fluidic non-moving-part controllers to produce water-hammer pulsations stimulated a need to simulate the fluid dynamics of such drill strings to aid the design work. The method of simulation chosen was transmission line modelling (TLM). It is essentially a time-delay method, borrowing its main concepts and the fundamentals of its computational solution scheme from early work by others in the field of electrical power lines. In its elementary form, a fluid network is treated as a set of pipes (or pipe segments) where waves travel with pure time delay. Connecting the pipes are junctions of various types at which the waves are scattered (transmitted, reflected and/or attenuated). The merits and limitations expected with this methodology in comparison with the method of characteristics (MOC) and other wave-analysis methods are discussed. The first adaptations of TLM were for small perturbation analysis. The presentation here takes such work further forward to model large-scale waves in pipe networks of almost arbitrarily complex topology. The basic theory behind the method is presented and the solution schemes are formulated mathematically with comments on the type of data structure and algorithms needed to undertake computationally such solutions. With the aid of modules described elsewhere, providing comprehensive steady state modelling capability, the software provides a powerful tool for implementing static and dynamic TLM simulations of networks. One of the novel aspects of considerable benefit is the ease of implementation of time-varying junctions capable of representing the overall action of control elements such as the fluidic controllers mentioned earlier. A large experimental laboratory facility with a simple circuit containing the essential hydrodynamics of drill strings was used to gather data on water-hammer pulsations. A controlled solenoid valve with a high-resistance bypass acted as an alternating high and low resistance in the main pipe loop. A simplified version of the circuit was simulated with TLM to compare and discuss the results. The TLM time-domain results took a few seconds of computer processing time and revealed the basic features of the circuit dynamics quantifying water-hammer to a fair and useful accuracy. Such results were encouraging and confirmed the power of this computational method as an aid in the design process.
2
Kamil, Raihan, Pranda M. P. Garniwa, and Hyunjin Lee. "Performance Assessment of Global Horizontal Irradiance Models in All-Sky Conditions." Energies 14, no. 23 (November 26, 2021): 7939. http://dx.doi.org/10.3390/en14237939.
Повний текст джерелаАнотація:
Solar irradiance models contribute to mitigating the lack of measurement data at a ground station. Conventionally, the models relied on physical calculations or empirical correlations. Recently, machine learning as a sophisticated statistical method has gained popularity due to its accuracy and potential. While some studies compared machine learning models with other models, a study has not yet been performed that compares them side-by-side to assess their performance using the same datasets in different locations. Therefore, this study aims to evaluate the accuracy of three representative models for estimating solar irradiance using atmospheric variables measurement and cloud amount derived from satellite images as the input parameters. Based on its applicability and performance, this study selected the fast all-sky radiation model for solar applications (FARMS) derived from the radiative transfer approach, the Hammer model that simplified atmospheric correlation, and the long short-term memory (LSTM) model specialized in sequential datasets. Global horizontal irradiance (GHI) data were modeled for five distinct locations in South Korea and compared with hourly measurement data of two years to yield the error metrics. When identical input parameters were used, LSTM outperformed the FARMS and the Hammer model in terms of relative root mean square difference (rRMSD) and relative mean bias difference (rMBD). Training an LSTM model using the input parameters of FARMS, such as ozone, nitrogen, and precipitable water, yielded more accurate results than using the Hammer model. The result shows unbiased and accurate estimation with an rRMSD and rMBD of 23.72% and 0.14%, respectively. Conversely, the FARMS has a faster processing speed and does not require significant data to make a fair estimation.
3
Holzschuh, Josef. "Low‐cost geophysical investigations of a paleochannel aquifer in the Eastern Goldfields, Western Australia." GEOPHYSICS 67, no. 3 (May 2002): 690–700. http://dx.doi.org/10.1190/1.1484512.
Повний текст джерелаАнотація:
Compressional (P) wave and shear (S) wave seismic reflection techniques were used to delineate the sand and gravel aquifer within a highly saline clay‐filled paleochannel in the Eastern Goldfields of Western Australia. The seismic refraction and gravity methods were also used to investigate the paleochannel. The unsaturated loose fine‐grained sand up to 10 m in depth at the surface is a major factor in degrading subsurface imaging. The seismic processing needed to be precise, with accurate static corrections and normal moveout corrections. Deconvolution enhanced the aquifer and other paleochannel reflectors. P‐wave reflection and refraction layer depths had good correlation and showed a total of six boundaries: (1) water table, (2) change in velocity (compaction) in the paleochannel sediments, (3) sand and gravel aquifer, (4) red‐brown saprolite and green saprolite boundary, (5) weathered bedrock, and (6) unweathered bedrock. P‐wave explosive and hammer sources were found to have similar signal characteristics, and the aquifer and bedrock were both imaged using the hammer source. The deep shots below the water table have the most broadband frequency response for reflections, but stacking clear reflections was difficult. The S‐wave reflection results showed high lateral and vertical resolution of the basal saprolite clay, the sand and gravel aquifer, and very shallow clays above the aquifer. The S‐wave reflection stacking velocities were 10–20% of the P‐waves, increasing the resolution of the S‐wave section. The gravity data were modelled to fit the known drilling and P‐wave seismic reflection depths. The refraction results did not identify the top of bedrock, so refraction depths were not used for the gravity modeling in this highly weathered environment. The final gravity model mapped the bedrock topography beyond the lateral extent of the seismic and drilling data.
4
Shin, Ban-Sok, Luis Wientgens, Marius Schaab, and Dmitriy Shutin. "Near-Surface Seismic Measurements in Gravel Pit, over Highway Tunnel and Underground Tubes with Ground Truth Information as an Open Data Set." Sensors 22, no. 17 (September 4, 2022): 6687. http://dx.doi.org/10.3390/s22176687.
Повний текст джерелаАнотація:
In this article, we describe in detail three seismic measurement campaigns based on refraction methods that we conducted at different sites in Bavaria, Germany. The measured data is published as an open data set. The particularity of this data set lies in its available ground truth information about each measurement site. Acquiring seismic data from sites with ground truth information is important for validation of seismic inversion algorithms. Since near-surface seismic field data with ground truth information is rather limited, we anticipate this data set to be a valuable contribution to the research community. For the measurements, three sites have been selected: (1) a gravel pit with a ground water layer, (2) a site above a highway tunnel and (3) a surface over underground tubes. The measurements have been conducted using line arrays of geophones, the Geode Seismograph from Geometrics Inc. and hammer strikes as seismic source. To obtain inversion results a travel time tomography based on first-arrivals within the software SeisImager is used. The inversion results show that we are able to image the ground water layer in the gravel pit, the highway tunnel and partly features of underground tubes. Furthermore, the results coincide with available ground truth information about the measurement sites. This paper summarizes the measurement campaigns and the respective data sets obtained through these campaigns. The data have been published by the authors as an open data set under the license CC BY 4.0 on figshare to make it available to the research community for validation of seismic data processing and inversion techniques.
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Ostapenko, S. P., and S. P. Mesyats. "Methodological approach to characterizing pollution of natural water bodies using satellite data with account of aggregation of finely dispersed mineral processing waste." Mining Industry Journal (Gornay Promishlennost), no. 6/2021 (January 15, 2022): 110–16. http://dx.doi.org/10.30686/1609-9192-2021-6-110-116.
Повний текст джерелаАнотація:
The level of the environmental impact of the mining industry specifies the urgency of ecological management of the natural resources based on the satellite monitoring data. The high content of the suspended mineral particles in the industrial waters and the requirement to reduce their access to the natural water reservoirs determine the need to characterize the mininginduced pollution that can be carried out correctly with due account of the aggregate stability of dispersions. In spite of the theoretical concepts, prediction of the particles aggregation is limited by a lack of data on their interaction parameters. In order to parametrize the interactions in the mineral-water-mineral system it is proposed to use experimental data on aggregation of finely dispersed particles, obtained by the laser diffraction method in the equilibrium conditions. For this purpose the procedure of the experimental appraisal of the effective Hamaker constants has been elaborated using ores of developed deposits of the Kola mining complex as an example. The authors have studied the conditions of the surface layer of natural water reservoirs in the most industrially developed central part of the Murmansk region and defined characteristics of pollution with finely dispersed by-products of the mineral raw material treatment, according to the satellite observation data of the spatial distribution of the normalized difference turbidity index. The authors have established that the least propagation of the pollution into the natural water reservoirs is observed in the case of the apatite-nepheline ores processing by-products, which is explained by the effective aggregation of the finely dispersed nepheline particles. The proposed approach to apply data on mineral particles aggregation for interpretation of the satellite observations does not require carrying out in-situ observations and makes it possible to identify the mining-induced pollution of natural water reservoirs in industrial territories using suspended particles.
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Potapov, Peter, Matthew C. Hansen, Indrani Kommareddy, Anil Kommareddy, Svetlana Turubanova, Amy Pickens, Bernard Adusei, Alexandra Tyukavina, and Qing Ying. "Landsat Analysis Ready Data for Global Land Cover and Land Cover Change Mapping." Remote Sensing 12, no. 3 (January 29, 2020): 426. http://dx.doi.org/10.3390/rs12030426.
Повний текст джерелаАнотація:
The multi-decadal Landsat data record is a unique tool for global land cover and land use change analysis. However, the large volume of the Landsat image archive and inconsistent coverage of clear-sky observations hamper land cover monitoring at large geographic extent. Here, we present a consistently processed and temporally aggregated Landsat Analysis Ready Data produced by the Global Land Analysis and Discovery team at the University of Maryland (GLAD ARD) suitable for national to global empirical land cover mapping and change detection. The GLAD ARD represent a 16-day time-series of tiled Landsat normalized surface reflectance from 1997 to present, updated annually, and designed for land cover monitoring at global to local scales. A set of tools for multi-temporal data processing and characterization using machine learning provided with GLAD ARD serves as an end-to-end solution for Landsat-based natural resource assessment and monitoring. The GLAD ARD data and tools have been implemented at the national, regional, and global extent for water, forest, and crop mapping. The GLAD ARD data and tools are available at the GLAD website for free access.
7
Lyu, Beichen, Stuart D. Smith, Yexiang Xue, Katy M. Rainey, and Keith Cherkauer. "An Efficient Pipeline for Crop Image Extraction and Vegetation Index Derivation Using Unmanned Aerial Systems." Transactions of the ASABE 63, no. 4 (2020): 1133–46. http://dx.doi.org/10.13031/trans.13661.
Повний текст джерелаАнотація:
HighlightsThis study addresses two computational challenges in high-throughput phenotyping: scalability and efficiency.Specifically, we focus on extracting crop images and deriving vegetation indices using unmanned aerial systems.To this end, we outline a data processing pipeline, featuring a crop localization algorithm and trie data structure.We demonstrate the efficacy of our approach by computing large-scale and high-precision vegetation indices in a soybean breeding experiment, where we evaluate soybean growth under water inundation and temporal change.Abstract. In agronomy, high-throughput phenotyping (HTP) can provide key information for agronomists in genomic selection as well as farmers in yield prediction. Recently, HTP using unmanned aerial systems (UAS) has shown advantages in both cost and efficiency. However, scalability and efficiency have not been well studied when processing images in complex contexts, such as using multispectral cameras, and when images are collected during early and late growth stages. These challenges hamper further analysis to quantify phenotypic traits for large-scale and high-precision applications in plant breeding. To solve these challenges, our research team previously built a three-step data processing pipeline, which is highly modular. For this project, we present improvements to the previous pipeline to improve canopy segmentation and crop plot localization, leading to improved accuracy in crop image extraction. Furthermore, we propose a novel workflow based on a trie data structure to compute vegetation indices efficiently and with greater flexibility. For each of our proposed changes, we evaluate the advantages by comparison with previous models in the literature or by comparing processing results using both the original and improved pipelines. The improved pipeline is implemented as two MATLAB programs: Crop Image Extraction version 2 (CIE 2.0) and Vegetation Index Derivation version 1 (VID 1.0). Using CIE 2.0 and VID 1.0, we compute canopy coverage and normalized difference vegetation indices (NDVIs) for a soybean phenotyping experiment. We use canopy coverage to investigate excess water stress and NDVIs to evaluate temporal patterns across the soybean growth stages. Both experimental results compare favorably with previous studies, especially for approximation of soybean reproductive stage. Overall, the proposed methodology and implemented experiments provide a scalable and efficient paradigm for applying HTP with UAS to general plant breeding. Keywords: Data processing pipeline, High-throughput phenotyping, Image processing, Soybean breeding, Unmanned aerial systems, Vegetation indices.
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Schneider, William A., Lindy D. Phillip, and Ernest F. Paal. "Wave‐equation velocity replacement of the low‐velocity layer for overthrust‐belt data." GEOPHYSICS 60, no. 2 (March 1995): 573–79. http://dx.doi.org/10.1190/1.1443795.
Повний текст джерелаАнотація:
Seismic land data are commonly plagued by nonhyperbolic distortions induced by a variable near‐surface, low‐velocity layer (LVL). First‐arrival refraction analysis is conventionally employed to estimate the LVL geometry and velocities. Then vertical static time shifts are used to replace the LVL velocities with the more uniform, faster velocities that characterize the underlying refracting layer. This methodology has earned a good reputation as a geophysical data processing tool; however, velocity replacement with static shifts assumes that no ray bending occurred at the LVL base and that waves propagated vertically through the LVL (even though conventional refraction analysis methods, which are used to derive LVL models from seismic data, are less restrictive). These assumptions often are inadequate in thick, complex LVL situations, where resulting errors may considerably hamper a statics‐based velocity replacement procedure. Wave‐equation datuming may be used to perform LVL velocity replacement when statics are inadequate. This method extrapolates the seismic data from the surface to the LVL base with the LVL velocities. Then it extrapolates the data from the LVL base to an arbitrary datum, with the replacement velocity field. The marine analog of such a procedure has been well documented in the geophysical literature, where the object is to remove distortions caused by an irregular water layer. Application of wave‐equation datuming to land data is more difficult because of certain common characteristics of land data (irregular shooting, large data gaps, and crooked line geometry, combined with lower signal/noise) and because the LVL estimation procedure is considerably more difficult. We demonstrate wave‐equation velocity replacement on land data from a western U.S. overthrust belt. The LVL in this region was particularly thick and complicated and ideal for a wave‐theoretical velocity‐replacement procedure. Standard refraction analysis techniques were employed to estimate the LVL, then wave‐equation datuming was used to perform the velocity replacement. Our derived LVL model was not perfect, so some imaging errors were expected because wave‐equation datuming is highly dependent upon the LVL model. Nevertheless, our results show that wave‐equation datuming generally allowed better shallow reflector imaging than could be achieved with conventional statics processing.
9
Li, xiu, hao jie Yang, pei lin Dou, and shi fa Zhao. "Analysis on water hammer protection of FPSO ballast water system." Journal of Physics: Conference Series 2029, no. 1 (September 1, 2021): 012125. http://dx.doi.org/10.1088/1742-6596/2029/1/012125.
Повний текст джерелаАнотація:
Abstract In practical engineering, the protection of FPSO water hammer is very important. Through simulation analysis, the relevant data are obtained to provide reference for relevant engineering practice. A general-purpose FPSO ballast water pipe network system was established by aft impulse software, and water hammer simulation calculation and analysis were carried out to find out the maximum pressure position of water hammer phenomenon. According to the water hammer generation mechanism, the simulation research was carried out by two-stage valve closing and adding surge tank into the pipeline. It was found that water hammer was easily caused by quick closing valve; the protection method of two-stage valve closing and installation of surge tank has a very objective protective effect, which provides a reference for related projects.
10
Naami, Augustina, and Emmanuel Kwabena Naami. "Women in the shea industry: The case of Kusawgu in the Northern Region of Ghana." Social Work and Social Sciences Review 20, no. 1 (April 6, 2019): 26–46. http://dx.doi.org/10.1921/swssr.v20i1.1273.
Повний текст джерелаАнотація:
: This research sought to highlight the experiences of women in the shea industry in Kusawgu in Ghana. Recommendations to enhance and sustain the industry were also explored. A total of 60 women from four shea production groups, who lived in Kusawgu, participated in focus group discussions. The data was first analysed separately by the two researchers. Results were then compared to reconcile differences. The study demonstrates that the shea industry undoubtedly provided means of livelihood, self-dignity and respect for the women. Positive outcomes for working in groups include quick processing; sense of belonging and social capital; security and peace of mind; and skills development. However, lack of access to microfinance, travelling for longer distances, the period of time required to get water and fuel-wood, gender-based land ownership discrimination, and extinction of shea trees hamper production and income. Regardless of these challenges the women demonstrated resiliency by their continuous work in the industry. Due to the potential of the shea industry to reduce poverty among women, government should work hand-in-hand with the traditional authority to develop measures to sustain the industry. Social work practitioners could build the capability of the women in the shea industry to access existing pro-poor programmes.
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Косолапов, В. М., С. И. Тютюнов, А. Э. Ставцев, and С. В. Зверев. "Optimization of hammer grinder for white lupine “Dega” processing." Кормопроизводство, no. 2(2021) (March 25, 2021): 36–41. http://dx.doi.org/10.25685/krm.2021.2021.2.007.
Повний текст джерелаАнотація:
Исследования проведены в 2019 году в лаборатории «Технология и техника мукомольно-крупяного производства» ВНИИ зерна и продуктов его переработки – филиала ФГБНУ «ФНЦ пищевых систем им. В. М. Горбатова» РАН. В качестве объекта исследований использовали зерно белого люпина сорта Дега. Эксперименты по изучению условий измельчения зерна проводились на лабораторной молотковой дробилке с регулируемой частотой вращения ротора. Рассматривалось влияние влажности зерна, скорости молотков и диаметра отверстий рабочего сита дробилки на выход крупки и содержание в ней недоруша (зёрен и частиц с остатками оболочки, крупных частей неотвеянной оболочки). Использование простой технологической схемы обрушения зерна белого люпина на базе молотковой дробилки позволило получить до 70% крупки с повышенным содержанием белка и низким содержанием клетчатки. С ростом скорости молотков и уменьшением диаметра отверстий рабочего сита дробилки выход крупки снижался, что объяснимо ростом доли мелкой фракции, которая отвеивается при пневмосепарации. Крупка представляет из себя частицы ядра с недорушем, а относы являются смесью дроблёной оболочки с мучкой — мелкой фракцией дробленого ядра. Основная доля мучки ядра была сосредоточена во фракции меньше 1,5–2,0 мм, в которой содержится больше белка. Данная фракция составляла около половины массы относов или около 15% от массы зерна. Наличие недоруша в крупке повышало содержание в ней клетчатки и снижало содержание белка. С ростом влажности и диаметра отверстий рабочего сита дробилки содержание недоруша возрастало, а при росте скорости — падало. При фиксированной влажности содержание недоруша можно снизить за счёт повышения скорости удара (увеличения числа оборотов) или уменьшения диаметра отверстий рабочего сита дробилки, но и тот и другой метод повышают энергозатраты. При возрастании скорости удара росла и производительность. The research was conducted in 2019. Hammer grinder with adjustable rotor speed was used to crush the grain of white lupine “Dega”. The effects of grain water content, crushing speed and sieve size were analyzed on grain crushing and hulling as well as the proportion of unhulled grain. This technology resulted in up to 70% of crushed hulled grain rich in protein but poor in fiber. Increase in hammer speed and decrease in sieve size negatively affected the proportion of crushed grain due to the high content of fine fractions discarded further via pneumatic separation. Crushed hulled grain is normally combined with unhulled grain. The mixture of crushed hulls and fine particles of crushed grain are to be separated. Most of the bran was found in the fraction of 1.5–2.0 mm containing more protein. This fraction amounted to 15% of grain mass and 50% of the mass to be discarded. Unhulled grain mixed with crushed hulled grain increased fiber content in the mixture but reduced protein concentration. Higher grain water content and larger sieve size increased the amount of unhulled grain, while higher hammer speed decreased its fraction. Higher hammer speed as well as smaller sieve size reduce the content of unhulled grain but increased energy costs under constant grain water content. Increase in hammer speed improved the capacity of the grinder.
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Lu, Zhaohui, Zongyi Qin, Michael Hood, Yiyu Lu, and Dihon Tadic. "Numerical modelling of percussion water jets driven by multiple collisions." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 5 (June 30, 2014): 976–84. http://dx.doi.org/10.1177/0954406214541797.
Повний текст джерелаАнотація:
A numerical model is proposed in this research to analyse the behaviour of the pulse jet driven by percussion hammer. The mass of the hammer is usually larger than that of the piston and the resistance of compressed water can low down the piston, thus multiple collisions occur each time when the hammer strikes the piston. The proposed model has the merit to consider various striking possibilities to simulate the process of pulse water jet generated by multiple hammer collisions. In addition, a hammer-driven percussion pulse jet is developed and the corresponding experiments are carried out for verifying the reliability of the numerical model. Comparison results show that the predicted pressure and velocity values match well with the experimental data. The simulation of the generation of pulsed jet reveals the collisions and motions of the hammer and the piston and provides understanding of the mechanism of the pulse jet generation. The design of the hammer-driven pulse water jet device can be optimised through modelling different combinations of the parameters of the chamber, hammer, piston and nozzle for a specific purpose of rock fragmentation.
13
Choct, M., E. A. D. Selby, D. J. Cadogan, and R. G. Campbell. "Effects of particle size, processing, and dry or liquid feeding on performance of piglets." Australian Journal of Agricultural Research 55, no. 2 (2004): 237. http://dx.doi.org/10.1071/ar03105.
Повний текст джерелаАнотація:
Currently, most feed grains are processed by either hammer mill or roller mill before the inclusion in pig diets. However, the effect of these two types of milling and particle size on the performance and feed utilisation has not been adequately examined. The effect of milling processing (hammer mill v. roller mill), particle size, and feeding method (liquid v. dry) was assessed in a factorial design with 120 weaner pigs over 21 days. These pigs had been weaned for 7 days when the experiment commenced. The results revealed that pigs fed on hammer-milled diets had a better performance than those on roller-milled diets. Particle size of hammer-milled diets did not affect the performance of pigs, but influenced the digestible energy content of the diets. However, the feed conversion ratio was poorer for pigs fed coarsely or medium roller-milled diets only at Day 7–14 after weaning. There was a marked advantage in terms of feed efficiency associated with liquid feeding. For pigs offered the hammer-milled diets between 0 and 14 days, simply adding the feed to water improved feed efficiency by some 22%. For the roller-milled diets the corresponding improvement in feed efficiency was 28%. Liquid feeding improved digestible energy (DE) value by 1.5 MJ/kg for medium particle size and depressed DE value by 0.8 MJ/kg for fine particle size for hammer mill. Liquid feeding improved DE values for both medium and fine particle treatments by 0.9 MJ/kg for roller-milled diets. It should be noted that the full advantages of liquid feeding could only be taken if feed wastage from this system can be minimised as much as possible.The study was conducted to investigate if processing method (roller v. hammer mill), particle size (coarse, medium, and fine), and feeding method (liquid v. dry) significantly improved the growth rate, feed intake, and feed conversion of the weaner pig.
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Zhao, Li, Yusi Yang, Tong Wang, Wensheng Han, Rongchu Wu, Pengli Wang, Qiaoning Wang, and Liang Zhou. "An Experimental Study on the Water Hammer with Cavity Collapse under Multiple Interruptions." Water 12, no. 9 (September 14, 2020): 2566. http://dx.doi.org/10.3390/w12092566.
Повний текст джерелаАнотація:
Pressurized pipeline system damage is primarily caused by the highly destructive water hammer force. Currently, research on water hammer-caused collapse is mostly based on single-point collapse cases, but water hammer research, which involves multipoint collapse, is insufficient. Here, we establish an experimental platform to realize water hammers with multipoint collapse. With different schemes, i.e., various initial flow rates and valve closing speeds, we observed the hydraulic transient process with a high-speed camera, analyzed its characteristics and explained experimental phenomena with theoretical knowledge. Using experimental data analysis, we summarized the influencing factors and laws of the cavity length and water hammer pressure. Flow and pressure data for the different schemes were recorded to provide basic simulation data. Water column separation experimental phenomena were observed: completely atomized, completely cavitated and partially cavitated, and both cavitated and atomized. At the pump outlet, three hydraulic transition states occurred simultaneously in the horizontal pipe section: completely atomized, completely cavitated, and both cavitated and atomized. Two hydraulic transition states occurred in the knee region: completely and partially cavitated, and without atomization. The experimental results reveal that the initial flow rate and valve closing speed greatly affect the water hammer pressure rise and cavity length. The higher the initial flow rate and valve closing speed are, the larger the water hammer pressure rise and cavity length are.
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Azoury, P. H., M. Baasiri, and H. Najm. "On the Optimum Utilization of Water Hammer." Proceedings of the Institution of Mechanical Engineers, Part A: Power and Process Engineering 202, no. 4 (November 1988): 249–56. http://dx.doi.org/10.1243/pime_proc_1988_202_035_02.
Повний текст джерелаАнотація:
The computerized method of characteristics was used to analyse, for a single pipeline discharging into the atmosphere, the effects of valve-closure schedule and pipe length on optimum water-hammer strength. It was found that the criteria of optimum water-hammer utilization are a non-linear inherent valve schedule in which the bulk of the pressure surge occurs near the beginning or towards the end of valve closure, together with as small a value of dimensionless valve-closure time and as high a value of wide-open valve area as is consistent with cavitation-free operation. Also, a comparison of the results with hydraulic ram test data suggests that optimum drive pipe length may be based solely on optimum water-hammer strength, in the light of the relative effects of pipe friction and dimensionless valve-closure time. In general, optimum pipe length is not highly sensitive to inherent valve-closure schedule, water-hammer strength, pipe size or reservoir head.
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Sadek, Mohammad, and Ying Chen. "Discrete element modelling (DEM) of hemp processing using a hammermill." Canadian Biosystems Engineering 63, no. 1 (February 7, 2022): 2.01–2.11. http://dx.doi.org/10.7451/cbe.2021.63.2.1.
Повний текст джерелаАнотація:
The discrete element method (DEM) was used to develop a model to simulate hemp processing using a hammer mill. The model was computed using a commercial software package - Particle Flow Code in Three Dimensions (PFC3D). In the model, a simulated hemp stem was defined using spherical particles connected with parallel bonds implemented in the PFC3D. The breakage of the bonds mimics the hemp breaking phenomenon within the hammermill. A micro property, bond strength of the hemp stems, was calibrated using the literature data from compression tests of hemp stems. The calibrated bond strength was 2.2 x106 Pa. With the calibrated bond strength, the model was used to simulate the power and energy distributions within the hammermill. The simulations were performed for different hammer rotational speeds and feeding masses. The results showed that both the specific kinetic and strain energies increased with the increase of the feeding mass; however, the effects of the hammer rotational speed did not follow any particular trends.
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Ding, Yi, Feng Niu, Shi Min Zhang, Jin Jun Zhang, Wei Zhang, and Guang Yang. "The Optimized Design of Coanda Effect Control Switch in the Water Hammer Vibrator." Applied Mechanics and Materials 644-650 (September 2014): 276–81. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.276.
Повний текст джерелаАнотація:
As injector injects coiled tubing into well to a certain depth, the coiled tubing is unable to be injected continuously because of the increasing friction between the coiled tubing and the wellbore. With the core technology being an effective role in the Coanda Effect control switch, the Water Hammer Vibrator may extend the depth of the coiled tubing into the wellbore. Firstly, the paper verifies the effectiveness of the Coanda Effect control switch in Water Hammer Vibrator. Secondly, it optimizes the structure of the Coanda Effect control switch and improves the driving force of the piston of the water hammer vibrator without changing the injection flow rate, pressure and the other boundary conditions. Finally, it obtains varying patterns of the hydraulic cylinder pressure at both ends in the process of the Coanda feedback and trigger action by the experiment of the Coanda Effect control switch to measure pressure at both ends of hydraulic cylinder with the NI data acquisition unit. The results confirm the validity of the optimized Coanda Effect control switch in water hammer vibrator, so as to ensure the implementation and improvement in the water hammer effect of Water Hammer Vibrator.
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Bousbia-Salah, Anis. "Assessment of water hammer effects on boiling water nuclear reactor core dynamics." Nuclear Technology and Radiation Protection 22, no. 1 (2007): 18–33. http://dx.doi.org/10.2298/ntrp0701018b.
Повний текст джерелаАнотація:
Complex phenomena, as water hammer transients, occurring in nuclear power plants are still not very well investigated by the current best estimate computational tools. Within this frame work, a rapid positive reactivity addition into the core generated by a water hammer transient is considered. The numerical simulation of such phenomena was carried out using the coupled RELAP5/PARCS code. An over all data comparison shows good agreement between the calculated and measured core pressure wave trends. However, the predicted power response during the excursion phase did not correctly match the experimental tendency. Because of this, sensitivity studies have been carried out in order to identify the most influential parameters that govern the dynamics of the power excursion. After investigating the pressure wave amplitude and the void feed back responses, it was found that the disagreement between the calculated and measured data occurs mainly due to the RELAP5 low void condensation rate which seems to be questionable during rapid transients. .
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Lupa, S.-I., M. Gagnon, S. Muntean, and G. Abdul-Nour. "Investigation of Water Hammer Overpressure in the Hydraulic Passages of Hydropower Plants Equipped with Francis Turbines." IOP Conference Series: Earth and Environmental Science 1079, no. 1 (September 1, 2022): 012003. http://dx.doi.org/10.1088/1755-1315/1079/1/012003.
Повний текст джерелаАнотація:
Abstract Water hammer shortens hydraulic passage lifespan and may cause sudden failure. The primary goal is to use a hierarchical approach to assess the main parameters associated with water hammer. This will help investigate their influence and assist in decision making. Analytical calculation results and a numerical model are compared against experimental data. Our investigations examine water hammer overpressure loading induced by transient regimes. We used data from experimental campaigns carried out within the Hydro-Québec fleet that cover different types of hydraulic turbines and hydraulic passage configurations as experimental dataset. Guide vane closing rate was the main parameter controlled during the overpressure experiments and a general trend was identified for overpressure. This empirical trend is compared to model estimates in order to validate the hypothesis taken into account for calculations. An in-depth understanding of the water hammer phenomenon helps to select the appropriate theoretical model and recommend the optimal operating parameters to extend lifetime and to avoid catastrophic failures. Our study case suggests that available experimental data can be used along with gradually increasing analysis complexity to identify the optimal methodology for a given configuration.
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Jacobs, Trent. "ConocoPhillips’ Water-Hammer Analysis Highlights Potential for a Complex Dataset." Journal of Petroleum Technology 73, no. 07 (July 1, 2021): 22–25. http://dx.doi.org/10.2118/0721-0022-jpt.
Повний текст джерелаАнотація:
It has often amounted to little more than background noise. Now, engineers with one of the largest shale producers in the US consider the water-hammer signal to represent a potential trove of insight into stimulation performance. ConocoPhillips has spent almost 3 years developing a new approach to water-hammer analysis and recently shared the first public details of that work in a technical paper (SPE 204154). Perhaps the core takeaway is that within a few minutes of post-stage data, a picture of reservoir and stimulation quality is available. The challenge lies in how to bring that picture into proper focus. The water hammer is a pressure pulse that moves through the wellbore at the speed of sound in fluid, or around 5,000 ft/s, which is more than four-fold the speed of sound in air. Its name comes from the often-audible slam made on one end of the pipe when a column of moving fluid is slowed or halted. One is usually generated as a valve is turned, or a pump slowed or stopped at the end of a fracture stage. This makes the water hammer ubiquitous in the context of hydraulic-fracturing operations the world over. As the wave bounces up and down the wellbore it generates noticeable pressure spikes on wellhead gauges. These oscillating signatures have been the subject of industry intrigue for decades. They’ve also proven to be difficult to decipher and trust. As such, the water hammer has not entered into the shale sector’s pantheon of fracture-design inputs. ConocoPhillips’ ongoing research and development project may help change that. Based on a review of treatment data from more than 150 of the operator’s low-permeability wells from an unnamed field in North America, those with fast-decaying water-hammer signals amounted to the best performers, achieving an output equivalent to 94–110% of their estimated recoveries. On the other hand, wells with more prolonged or low decay rates commonly fell 10–20% below their original type curve. “The high decay rates indicated more near-wellbore fracture surface area, which related to higher well productivity. While conversely, low decay rates mean less near-wellbore friction, longer fractures, lower well productivity,” explained Dung “Zoom” Nguyen. Nguyen is a staff completions engineer at ConocoPhillips and coauthor of the paper that she presented at the annual SPE Hydraulic Fracturing Technology Conference in May. She elaborated that analysis on frac hits, or fracture-driven interactions (FDIs), supports the relationship between fracture geometry and water-hammer decay rates, i.e., low decay rates equate to fewer, longer, and less-complex fractures.
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Axworthy, David H., and Normand Chabot. "Pressure transients in a Canadian sewage force main." Canadian Journal of Civil Engineering 31, no. 6 (December 1, 2004): 1039–50. http://dx.doi.org/10.1139/l04-067.
Повний текст джерелаАнотація:
Severe water hammer following pump shutdown was suspected to be the cause of pipe displacement at a pump station in Saguenay, Quebec, because it appeared that insufficient surge protection was installed on the force main. To confirm this assertion and prevent further pipe displacement, data logging of a field test of the sewage pump station undergoing power failure was conducted in combination with the development of a water-hammer computer model for the design of additional surge protection measures. This paper describes the results of field testing, both before and after the installation of additional surge protection, and the calibration of a method of characteristics water-hammer model that accounts for vaporous cavitation and unsteady friction effects within the force main. Good agreement is shown between measured and computed pressure head histories at the pump station and at a vacuum relief valve following loss of power to a pump. To the authors' knowledge, this paper presents one of the first applications of the unsteady friction model referenced in this paper to a real system.Key words: sewage, force main, pump, water hammer, unsteady friction, data logging.
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Yang, Shuai, Dazhuan Wu, Zhounian Lai, and Tao Du. "Three-dimensional computational fluid dynamics simulation of valve-induced water hammer." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 231, no. 12 (February 11, 2016): 2263–74. http://dx.doi.org/10.1177/0954406216631780.
Повний текст джерелаАнотація:
In this study, three-dimensional computational fluid dynamics simulation was adopted to evaluate the valve-induced water hammer phenomena in a typical tank-pipeline-valve-tank system. Meanwhile, one-dimensional analysis based on method of characteristics was also used for comparison and reference. As for the computational fluid dynamics model, the water hammer event was successfully simulated by using the sliding mesh technology and considering water compressibility. The key factors affecting simulation results were investigated in detail. It is found that the size of time step has an obvious effect on the attenuation of the wave and there exists a best time step. The obtained simulation results have a good agreement with the experimental data, which shows an unquestionable advantage over the method of characteristics calculation in predicting valve-induced water hammer. In addition, the computational fluid dynamics simulation can also provide a visualization of the pressure and flow evolutions during the transient process.
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Ghidaoui, Mohamed S., Ming Zhao, Duncan A. McInnis, and David H. Axworthy. "A Review of Water Hammer Theory and Practice." Applied Mechanics Reviews 58, no. 1 (January 1, 2005): 49–76. http://dx.doi.org/10.1115/1.1828050.
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Hydraulic transients in closed conduits have been a subject of both theoretical study and intense practical interest for more than one hundred years. While straightforward in terms of the one-dimensional nature of pipe networks, the full description of transient fluid flows pose interesting problems in fluid dynamics. For example, the response of the turbulence structure and strength to transient waves in pipes and the loss of flow axisymmetry in pipes due to hydrodynamic instabilities are currently not understood. Yet, such understanding is important for modeling energy dissipation and water quality in transient pipe flows. This paper presents an overview of both historic developments and present day research and practice in the field of hydraulic transients. In particular, the paper discusses mass and momentum equations for one-dimensional Flows, wavespeed, numerical solutions for one-dimensional problems, wall shear stress models; two-dimensional mass and momentum equations, turbulence models, numerical solutions for two-dimensional problems, boundary conditions, transient analysis software, and future practical and research needs in water hammer. The presentation emphasizes the assumptions and restrictions involved in various governing equations so as to illuminate the range of applicability as well as the limitations of these equations. Understanding the limitations of current models is essential for (i) interpreting their results, (ii) judging the reliability of the data obtained from them, (iii) minimizing misuse of water-hammer models in both research and practice, and (iv) delineating the contribution of physical processes from the contribution of numerical artifacts to the results of waterhammer models. There are 134 refrences cited in this review article.
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Kubrak, Michał, Agnieszka Malesińska, Apoloniusz Kodura, Kamil Urbanowicz, and Michał Stosiak. "Hydraulic Transients in Viscoelastic Pipeline System with Sudden Cross-Section Changes." Energies 14, no. 14 (July 6, 2021): 4071. http://dx.doi.org/10.3390/en14144071.
Повний текст джерелаАнотація:
It is well known that the water hammer phenomenon can lead to pipeline system failures. For this reason, there is an increased need for simulation of hydraulic transients. High-density polyethylene (HDPE) pipes are commonly used in various pressurised pipeline systems. Most studies have only focused on water hammer events in a single pipe. However, typical fluid distribution networks are composed of serially connected pipes with various inner diameters. The present paper aims to investigate the influence of sudden cross-section changes in an HDPE pipeline system on pressure oscillations during the water hammer phenomenon. Numerical and experimental studies have been conducted. In order to include the viscoelastic behaviour of the HDPE pipe wall, the generalised Kelvin–Voigt model was introduced into the continuity equation. Transient equations were numerically solved using the explicit MacCormack method. A numerical model that involves assigning two values of flow velocity to the connection node was used. The aim of the conducted experiments was to record pressure changes downstream of the pipeline system during valve-induced water hammer. In order to validate the numerical model, the simulation results were compared with experimental data. A satisfactory compliance between the results of the numerical calculations and laboratory data was obtained.
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Lupa, Sorin-Ioan, Martin Gagnon, Sebastian Muntean, and Georges Abdul-Nour. "The Impact of Water Hammer on Hydraulic Power Units." Energies 15, no. 4 (February 18, 2022): 1526. http://dx.doi.org/10.3390/en15041526.
Повний текст джерелаАнотація:
Water hammer influences the life cycle of hydraulic passages and may even cause catastrophic structural failures. Several catastrophic failures of hydraulic power units have been reported in the literature due to the effects of transient regimes. The objective of the study is to highlight the global trend in water hammer assessment and to quantify the effect of factors influencing overpressure in hydraulic passages during load rejection in different hydropower plants. A brief and concise literature review is conducted to document the parameters associated with the water hammer phenomenon and to thereby identify the necessary prerequisites to validate theoretical and numerical results against experimental data. The purpose of the analysis is to identify extreme transient loads on hydraulic passages in order to properly adapt hydropower unit operation, to make recommendations for design and industry, and to guide the progress of adapted models and numerical simulations to capture complex phenomena. Empirical correlations are determined based on the experimental data that are transferable from one unit to another, even if a deep flow analysis is performed. The experimental results confirm that the rapid closure rate of the guide vanes has a significant impact on the phenomenon. A third order polynomial equation is applied to capture the general overpressure trends. Equation parameters change from case to case depending on the type of hydraulic power unit, closing rate and the type of hydraulic passage. The results confirm also that overpressure values depend significantly on other factors, some of which are not usually taken into account (e.g., runner speed). Experimental correlations make it possible to understand the water hammer phenomenon, which could help not just assessing and optimizing loads, but also verifying and validating more complex physical models, to ensure that hydraulic passages are reliable. A well-documented analysis also makes it possible to optimize equipment design, improve and adapt maintenance programs and to recommend appropriate operating parameters to increase equipment lifespan, while preventing incidents.
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Kubrak, Michał, Apoloniusz Kodura, Agnieszka Malesińska, and Kamil Urbanowicz. "Water Hammer in Steel–Plastic Pipes Connected in Series." Water 14, no. 19 (October 2, 2022): 3107. http://dx.doi.org/10.3390/w14193107.
Повний текст джерелаАнотація:
This paper experimentally and numerically investigates the water hammer phenomenon in serially connected steel and HDPE pipes with different diameters. The aim of the laboratory tests was to obtain the time history of the pressure head at the downstream end of the pipeline system. Transient tests were conducted on seven different pipeline system configurations. The experimental results show that despite the significantly smaller diameter of the HDPE pipe compared to the steel pipe, introducing an HDPE section makes it possible to suppress the valve-induced pressure surge. By referring to the results of the experimental tests conducted, the comparative numerical calculations were performed using the fixed-grid method of characteristics. To reproduce pressure wave attenuation in a steel pipe, Brunone-Vitkovský instant acceleration-based model of unsteady friction was used. To include the viscoelastic behavior of the HDPE pipe wall, the one-element Kelvin–Voigt model was applied. By calibrating the unsteady friction coefficient and creep parameters, satisfactory agreement between the calculated and observed data was obtained. The calibrated values of parameters for a single experimental test were introduced in a numerical model to simulate the remaining water hammer runs. It was demonstrated that using the same unsteady friction coefficient and creep parameters in slightly different configurations of pipe lengths can be effective. However, this approach fails to reliably reproduce the pressure oscillations in pipeline systems with sections of significantly different lengths.
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Ivandic, Monika, Ayse Kaslilar, and Christopher Juhlin. "Subsurface seismic imaging with a hammer drilling source at an exploration drilling test center in Örebro, Sweden." Advances in Geosciences 56 (January 27, 2022): 163–69. http://dx.doi.org/10.5194/adgeo-56-163-2022.
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Abstract. Seismic imaging while drilling (SWD) technology offers possibilities of imaging ahead of the drill-bit, which could be useful for determining when to go from hammer drilling to core drilling. Also, seismic images of the surrounding rock can improve geological models which could be then used to guide drilling programs. An SWD field test was carried out in August 2020 at an exploration drilling test site in Örebro, Sweden, with the aim to determine if the signals from hammer drilling can be used for seismic imaging around the drill-bit in a hard-rock environment where the strong drill-rig noise interference is one of the main challenges. The test site had previously been investigated with various geophysical methods, geological mapping and diamond core drilling, and it therefore represented an ideal location to perform this feasibility study. After data pre-processing and cross-correlation with the trace from the geophone closest to the rig, the shot-gathers were vertically stacked over the length of a drill pipe to achieve further signal improvement. A comparison with the active seismic data shows reasonable agreement, in spite of the fact that the noise level is significant even after careful processing. However, the lack of clear reflections in the active seismic data, indicating no detectable changes in the bedrock lithology in the near surface, hinders the full assessment of the seismic signal generated with hammer drilling at this site.
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Yang, Yu Si, Ru Dong, and Jie Gao. "The Fehleranalyse Error Analysis of Fully Characteristic Curve of Pump to Be Nominalization and Study for the Influence on Result of Hydraulic Transients Calculation." Advanced Materials Research 250-253 (May 2011): 3696–701. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.3696.
Повний текст джерелаАнотація:
In this paper，by transforming the fully characteristic curve of pump with eighty specific speed to be numeralization he obtained fehleranalyse error of discrete data were analyzed based on the pump similarity theory and the difference between certain assumed condition and real situation in numeralization process. Then the influence of the fehleranalyse error of numeralization method on the pressure boost caused by Pump-off water hammer was computed by a Pump-off water hammer calculation within an real engineering project. The reliability of numeric calculation method of fully characteristic curve of Pump is proved.
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T. J. Bowser, P. R. Weckler, and R. Jayasekara. "DESIGN PARAMETERS FOR OPERATION OF A STEAM INJECTION HEATER WITHOUT WATER HAMMER WHEN PROCESSING VISCOUS FOOD PRODUCTS." Applied Engineering in Agriculture 19, no. 4 (2003): 447–51. http://dx.doi.org/10.13031/2013.14912.
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Gimaltdinov, Il'dus, Bulat Ziganshin, Ilgiz Galiev, Andrey Dmitriev, Al'bert Muhametshin, and Aleksandr Gricenko. "PREVENTIVE MAINTENANCE STRATEGY FOR CRUSHING EQUIPMENT." Vestnik of Kazan State Agrarian University 15, no. 3 (November 30, 2020): 71–76. http://dx.doi.org/10.12737/2073-0462-2020-71-76.
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The research was carried out in order to develop a mathematical model and a diagnostic complex to determine the residual life of the rotor bearings of hammer crushers. Residual life information is essential for proactive maintenance and to prevent equipment crashes. To achieve this goal, Kazan State Agrarian University (Republic of Tatarstan) carried out calibration studies of the dependence of the diagnostic parameters of vibration on the value of the radial clearances of the bearings. 3610 bearings with different radial clearances (0.02 mm, 0.08 mm, 0.13 mm, 0.2 mm, 0.27 mm) were alternately installed on the rotor of the KD-2 hammer mill, from the drive pulley side and from the fan side) and recorded the vibration parameters. The information was read using a piezoelectric sensor. Signal processing was performed using a VVM-201 vibrometer. The results of mathematical processing of these data are presented in earlier publications. To determine the change in the value of the radial clearance from the operating time in hours, retrospective studies were carried out directly in the agricultural enterprises of the Republic of Tatarstan: “Shaimurzinskoe agricultural enterprise named after A.Sh. Abdreev” of Drozhzhanovskiy region, JSC “Kiyatskoe”of Buinskiy region, the agricultural production complex “Ural”of Kukmorskiy region, etc. The average operating time of the bearings of the rotor of the hammer-type KD-2 forage grinder before the onset of a pre-failure state on the drive side was 1900 ... 2000 hours, on the fan side - 2000 ... 2100 h. Based on the results of the research, the values of the radial clearances and vibration parameters of the rolling bearings of the rotor of hammer crushers were experimentally established, the regularities of the change in the radial clearance of the rolling bearings of the rotor of hammer crushers were revealed depending on the operating time. The developed mathematical models for determining the radial clearance in the rotor bearings of the hammer crusher by vibration parameters and calculating the residual life are implemented in a diagnostic complex consisting of a commercially available VVM-201 vibrometer and a residual life attachment
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Achak, N., B. Bahrar, and K. Gueraoui. "Numerical modeling transient flow in plastic pipes." MATEC Web of Conferences 286 (2019): 07001. http://dx.doi.org/10.1051/matecconf/201928607001.
Повний текст джерелаАнотація:
We present a numerical code for calculating transient flow in plastic pipes, especially in the polyethylene pipe, to analysis effect of material viscoelasticity on water hammer phenomena. The set partial differential equations to be solved is obtained using conservation laws and behavior for the fluid and the pipe wall, associated with constitutive equations of the two media, and relationships compatibility of interfaces on velocities and stresses. A global digital processing is achieved using the method of characteristics. The results obtained are in good agreement with those found in the literature.
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Yu, Chao, Xiaodong Yu, Lei Zhang, Bhusan Neupane, and Jian Zhang. "Approximate approach for improving pressure attenuation accuracy during hydraulic transients." Water Supply 22, no. 3 (December 8, 2021): 3387–98. http://dx.doi.org/10.2166/ws.2021.394.
Повний текст джерелаАнотація:
Abstract The quasi-steady friction model is generally adopted in water hammer simulation in pipe network systems, which cannot accurately reflect the attenuation of pressure, while the existing unsteady friction model is challenging to use in complex pipe network systems. In this study, a convenient method for treating the friction term is proposed based on the Moody diagram. The attenuation process of water hammer pressure can be accurately reflected by reading the relationship curve between Reynolds number and the Darcy friction factor in the pipeline transient process. Combined with the classical water hammer experiment and the long pipe valve closing experiment in our laboratory, the accuracy of this model is verified, and the influence of absolute roughness (e) and Reynolds number (Re) on the model was analyzed as well. The results show that the pressure attenuation using the Method of Characteristics (MOC) and the proposed friction model has a good agreement with the experimental data. The absolute roughness has little influence on the results in hydraulically smooth pipe, while the minimum Reynolds number has a significant influence. When selecting the minimum Reynolds number, 2% ∼ 5% of the initial flow rate is recommended for calculation.
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Germanova, O. A., V. A. Germanov, M. Y. Stepanov, A. V. Germanov, I. O. Prokhorenko, and M. V. Piskunov. "THE INFLUENCE OF THE HYDRAULIC EFFECT OF THE BLOOD DYNAMICS AT THE EXTRASYSTOLY ON THE MORPHOLOGY OF MAINSTREAM ARTERIES." Morphological newsletter 27, no. 3 (September 30, 2019): 24–31. http://dx.doi.org/10.20340/mv-mn.2019(27).3.24-31.
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The influence of various types of extrasystole on the change in arterial hemodynamics and the morphology of changes in the wall of the mainstream arterial vessels is not well understood. The purpose of the study was to determine the effects of water hammer on the hemodynamics of the main arteries in various types of extrasystoly. The study was conducted on 228 patients (122 men and 106 women) aged 43 to 76 years, the average age was 62 ± 4.3 years. For the analysis, the data apex-cardiography, daily monitoring by Holter, echocardiography, electrocardiography, sphygmography, color Doppler mapping of the vessels of the head and neck and extremities were compared. Water hammer of extrasystoles leads to mechanical damage to the endothelium of the arterial wall and serves as a trigger for inflammation and activation of the process of neolipogenesis, the formation of the atheroma. Additional hydraulic waves contribute to trauma to the vascular wall, growth and increase in area of atheromas. The described morphological changes in the vascular wall, the authors describe as «water hammer syndrome» and analyze its role and pathophysiological mechanisms of the development of vascular complications at extrasystoles and reconstructive operations on arterial vessels.
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Adigamov, Nail R., Rafis R. Shaikhutdinov, Ildus H. Gimaltdinov, Rishat R. Akhmetzyanov, and Rafik S. Basyrov. "Determining the residual resource of the hammer crushers’ rotor bearings." BIO Web of Conferences 17 (2020): 00239. http://dx.doi.org/10.1051/bioconf/20201700239.
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The practice of operating machinery and equipment that are used in animal husbandry and in the processing of its products has shown low reliability of feed crushers. As of 01.01.2019, in the agricultural enterprises of the Republic of Tatarstan there are about 1200 machines for grinding feed, of which 800 pcs. are hammer crushers. Most of these crushers have a service life of 10 to 13 years and are objects with low reliability. Mostly emergency stops occur due to the destruction of the rotor bearings. In the event of a sudden failure, unplanned repairs and a decrease in production efficiency occur. At the Department of Operation and Repair of Machines of Kazan State Agrarian University, research was carried out and a scientific result was obtained, which was implemented in the adapter to the vibrometer to determine the residual life of rolling bearings. Input data for this device were obtained during operational research and further analysis of the data.
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Doroszuk, Błażej, and Robert Król. "Industry Scale Optimization: Hammer Crusher and DEM Simulations." Minerals 12, no. 2 (February 14, 2022): 244. http://dx.doi.org/10.3390/min12020244.
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The paper shows the preparation of the numerical models necessary for the simulation mapping of industrial-scale crushers of problematic material, such as copper ore with complex lithology. The crushers investigated in this work are located in the KGHM Polska Miedz S.A. copper ore processing plant. The complex ore consisting of sandstone, dolomite and shale is modeled using the Discrete Element Method (DEM) with Particle Replacement Model (PRM) that was chosen to simulate the crushing process. The article discusses the tests and calibration of material parameters and proceeds to test a breakage model in a laboratory-scale jaw crusher. The results are finally validated with the data from actual industrial-scale crushers and compared with the simulations. As an optimization option, the new shape of hammers is proposed and tested in a numerical environment. The performance of the newly designed hammers was examined using numerical methods. The numerical tests showed that the new design performed worse than the current solution. As a result, time and money were saved by avoiding industrial tests. In conclusion, the work shows how complex processes can be characterized in the numerical environment and used for further analysis.
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Aliabadi, Hamed Karimian, Ahmad Ahmadi, and Alireza Keramat. "Frequency response of water hammer with fluid-structure interaction in a viscoelastic pipe." Mechanical Systems and Signal Processing 144 (October 2020): 106848. http://dx.doi.org/10.1016/j.ymssp.2020.106848.
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Herasymov, Henrikh H., Ievgenii G. Gerasimov, Sergiy Y. Ivanov, and Oleg L. Pinchuk. "Experimental Study of the Effectiveness of a Combined Closure of the End Gate Pipeline Valve." Archives of Hydro-Engineering and Environmental Mechanics 66, no. 1-2 (June 1, 2019): 3–13. http://dx.doi.org/10.1515/heem-2019-0001.
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Abstract One of the ways to ensure a reliable operation of irrigation systems is to protect them from water hammer (hydraulic shock) damage that occurs when starting or stopping a pumping station. This can be achieved by creating conditions in which a water hammer will not occur in the pressure pipeline as a result of closing the end gate valve (EGV). The aim of the present study was to investigate processes occurring in the pipeline during a linear closure of the EGV, during a closure with one break point and during an intermittent closure, as well as to verify the effectiveness of a combined end gate valve closure of the pipeline. Based on experimental data and calculations, the article recommends a linear closure of the EGV with one break point.
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Wang, Feng Yuan, De Hui Huang, and Sheng Li. "Identification of Inertial Parameters of Heavy Truck Powertrains." Applied Mechanics and Materials 43 (December 2010): 225–28. http://dx.doi.org/10.4028/www.scientific.net/amm.43.225.
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Based on the quality of line frequency response function and the principle of rigid body micro-vibration, a technique was proposed to verify the experimental accuracy for the heavy truck powertrain by using rigid body inertia tensor transformation and additive theory. The measurement of inertial parameters of a heavy truck powertrain was carried out by hammer method. The total least square processing theory was proposed to process the experimental data. The experimental results showed satisfactory accuracy and reliability.
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Pangelova, Natalia, and Natalia Vasylenko. "COMPARATIVE ANALYSIS FUNCTIONAL CONDITION SENSOMOTOR SYSTEMS QUALIFIED METALISTS HAMMER (HEALTHY AND HEARING IMPAIRED)." Sports Bulletin of the Dnieper 1 (2020): 100–108. http://dx.doi.org/10.32540/2071-1476-2019-1-100.
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Introduction. Adaptation of the athlete's organism with auditory deprivation to training and competitive activity is ensured by the active participation of the central nervous system, sensory systems, among which the important role is played by visual, vestibular, kinesthetic, tactile-vibration analyzers, which ensure the quality of movement. In this regard, studying the activity of sensorimotor systems of healthy athletes and hearing impaired will determine the ways of correction of the motor activity of the latter. The objective - study and comparative analysis of physiological features of sensorimotor systems of qualified hammer throwers (healthy and hearing impaired). Materials and methods. Research methods: analysis, generalization and systematization of data scientific and methodological literature; psychophysiological methods (simple visual-motor reaction; reaction to a moving object; tepping test; choice and discrimination reaction; critical part of light flickering; attention assessment); methods of mathematical statistics. Nine female athletes specializing in hammer throwing participated in the study: 7 of them are masters of sports of Ukraine, 2 - masters of sports of international class (5 female athletes have hearing impairments, 4 are healthy). The studies were conducted in October-November 2019 at the Donetsk Regional Children's and Youth Sports School for Persons with Disabilities (Mariupol). Results. The studies suggest that the thrower hammer with hearing problems (especially in persons with bilateral sensorineural deafness), in most cases there is a lack of speed of receiving and processing visual information, poor concentration and stability of attention, increasing the number of errors compared to almost healthy athletes. It should also be noted in hammer throwers with hearing impairment that there is an imbalance of nerve processes with a predominance of inhibition, their weakness and inertia. Conclusions. The data obtained confirm the need for the development of a training program, the basis of which is a deliberate impact on visual and vestibular analyzers in order to correct existing abnormalities and compensate for hearing impairment by further improving the functioning of the motor analyzer. Key words: sensorimotor systems, functional state, hammer throwers, hearing defects.
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Glazyrin, Gleb, Yury Kazantsev, and Nikolay Tverdokhlebov. "The Transient Processes Simulation of Kaplan Turbine Operating in Propeller Modes." Applied Mechanics and Materials 698 (December 2014): 655–59. http://dx.doi.org/10.4028/www.scientific.net/amm.698.655.
Повний текст джерелаАнотація:
In this paper simulation of basic elements of hydropower plant (penstock, turbine, and generator) is considered. A new integral method of water hammer effect representation with elastic water column is proposed. The model of Kaplan turbine in propeller modes, considering the change of rotor speed during the transient process, is developed in Simulink simulation environment and tested for the case of real experimental data.
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Henclik, Sławomir. "Application of the shock response spectrum method to severity assessment of water hammer loads." Mechanical Systems and Signal Processing 157 (August 2021): 107649. http://dx.doi.org/10.1016/j.ymssp.2021.107649.
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Dvořák, Richard, and Libor Topolář. "Effect of Hammer Type on Generated Mechanical Signals in Impact-Echo Testing." Materials 14, no. 3 (January 28, 2021): 606. http://dx.doi.org/10.3390/ma14030606.
Повний текст джерелаАнотація:
The impact-echo diagnostic method is a well-known nondestructive pulse compression test method, which can be relatively easily used for the testing of concrete and reinforced concrete elements. The evaluation of the measurement with this method is based on the analysis of the signal itself in the time and frequency domains. This allows acquisition of information on the velocity of the mechanical wave, the resonant frequency of the specimen or on the presence of internal defects. The ability to interpret these measurements depends on the experience of the diagnostic technician. The advent of classification algorithms in the field of machine learning has brought an increasing number of applications where the entire interpretation phase can be considerably simplified with the help of classification models. However, this automated evaluation procedure must be provided with the information of whether the signal acquired by the test equipment has actually been measured under optimally set conditions. This paper proposes a procedure for the mutual comparison of different measuring setups with a variable tip type, hammer handle and impact force. These three variables were used for a series of measurements which were subsequently compared with each other using multi-criteria evaluation. This offers a tool for the evaluation of measured data and their filtering. As an output of the designed method, each measurement is marked by a score value, which represents how well the acquired signal fit the weight demands for each observed feature of the signal. The method allows the adjustment of selected demands for a specific application by means of set thresholds. This approach enables the understanding of characteristics of the signal in the automated pre-processing of measured data, where computing power is limited. Thus, this solution is potentially suitable for remote long-term observations with sensor arrays or for acoustic emission signals pre-processing.
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Bondarchuk, E. N., A. S. Pochtar, S. V. Vinogradov, and V. I. Popov. "Experimental studies of in-line gasification of mechanically activated coal fuel." Journal of Physics: Conference Series 2119, no. 1 (December 1, 2021): 012158. http://dx.doi.org/10.1088/1742-6596/2119/1/012158.
Повний текст джерелаАнотація:
Abstract The 1 MW experimental stand was modernized with a scroll swirler and a crushed fuel supply system. Comparative data on combustion and gasification of coal fuel crushed in high-stress mills - disintegrator, vibrocentrifugal and hammer mill - at a stand with a thermal power of 1 MW were obtained. The experiments used coal of the Kuznetsk Basin, grade D, with technical characteristics: Wr, % = 5.4; Ar, %=22.3; Vr, % = 32.3; Qsr, MJ/kg = 20.0. Elemental analysis showed that: Cr, %=54.6; Hr, % = 4.1; Nr, % = 1.3; Sr, % = 0.5; Or = 11.8. In experiments with grinding coal on a disintegrator mill, the value of H2 = 4.5 vol.% and CO = 9.4 vol.%, when grinding in a vibro-centrifugal mill, the values of H2 = 0.6 vol.% and CO = 5.8 vol.%, when grinding in a hammer mill, the values of H2 = 0.3 vol.% and CO = 2.8 vol.%. When studying the combustion of mechanochemically treated coal samples, it was found that, all other things being equal, the gasification parameters, namely, the gas concentration and the distribution of temperature zones, depend strongly on the type of equipment used for processing. In particular, processing to approximately the same degree of fineness in mechanical mills-activators with constrained impact and in free impact mills (disintegrators) resulted in different flame parameters.
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Oduntan, O. B., and B. O. Omitoyin. "Wear of disc mill hammer in wet grinding processes on groundnut cake for fish feed production." Research in Agricultural Engineering 61, No. 4 (June 2, 2016): 162–69. http://dx.doi.org/10.17221/67/2013-rae.
Повний текст джерелаАнотація:
There is need to determine the wear rates of disc mill hammer used for grinding groundnut cake, a major plant protein in fish feed. This surface wear damage characterised by scoring, cutting, deep grooving and gouging on a metal surface leads to high costs of production. The hammer wear rate was carried out using disc mill for different combinations of processing conditions: disc speed of 2,175, 3,900 and 4,350 rpm; screen size of 1.0, 2.0 and 3.0 mm; moisture contents of 12, 14 and 16% w.b. at 300 operating hours. Response Surface Method was used to optimize the operating variables. The wear rate was found to increase as the moisture content of the groundnut cake decreased. Quadratic models developed for the four responses (tip length loss, width loss, thickness loss and absolute mass) studied indicated the optimum conditions at disc speed 3,262.50 rpm, screen size 2.0 mm and moisture content 14% w.b. The study established that experimental data and model predictions agreed well.
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Hayfield, Colin, John Pouncett, and Pat Wagner. "Vessey Ponds: a ‘prehistoric’ water supply in East Yorkshire?" Proceedings of the Prehistoric Society 61 (1995): 393–408. http://dx.doi.org/10.1017/s0079497x00003145.
Повний текст джерелаАнотація:
Vessey Ponds are a pair of irregularly-shaped hollows high on the Chalk Wolds of East Yorkshire at about 220 m OD (Fig. 1). Recent fieldwalking recovered a large flint scatter in the vicinity of these hollows. Mesolithic activity was represented by worked flint displaying soft hammer technology whereas hard hammer technologies indicate Neolithic and Bronze Age tool production and usage. The presence of large numbers of cores and a vast quantity of industrial waste indicates on-site preparation of tools. Statistical analysis of the fieldwalking data implies that the flints are concentrated around the hollows. Auger sampling across the ponds revealed natural clay deposits that still hold water close to the pond surface. Consideration of exploitation of mineral resources on the Wold top and possible mechanisms of formation of Vessey Ponds highlights the complex effects of glacial activities on the local surface geology. Karstic origins for some features of surface geology are suggested. The nature of the ‘prehistoric’ economies represented by the flint scatter is considered along with ethnoarchaeological evidence to support the assumption that the ponds at Vessey were a potential water supply during the Mesolithic, Neolithic, and Bronze Ages. Evidence from Vessey Ponds and elsewhere in Yorkshire implies an association between areas of ‘prehistoric’ activity and the availability of surface water. Above all else, this work highlights the impact of water supply on settlement pattern and land use on the Chalk of the Yorkshire Wolds.
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Pal, Susovan, Prashanth Reddy Hanmaiahgari, and Martin F. Lambert. "Efficient approach toward the application of the Godunov method to hydraulic transients." Journal of Hydroinformatics 22, no. 5 (July 9, 2020): 1370–90. http://dx.doi.org/10.2166/hydro.2020.037.
Повний текст джерелаАнотація:
Abstract The proposed study investigated the applicability of the finite volume method (FVM) based on the Godunov scheme to transient water hammer with shock front simulation, in which intermediate fluxes were computed using either first-order or second-order Riemann solvers. Finite volume (FV) schemes are known to conserve mass and momentum and produce the efficient and accurate realization of shock waves. The second-order solution of the Godunov scheme requires an efficient slope or a flux limiter for error minimization and time optimization. The study examined a range of limiters and found that the MINMOD limiter is the best for modeling water hammer in terms of computational time and accuracy. The first- and second-order FVMs were compared with the method of characteristics (MOCs) and experimental water hammer measurements available in the literature. Both the FV methods accurately predicted the numerical and experimental results. Parallelization of the second-order FVM reduced the computational time similar to that of first-order. Thus, the study presented a faster and more accurate FVM which is comparable to that of MOC in terms of computational time and precision, therefore it is a good substitute for the MOC. The proposed study also investigated the implementation of a more complex convolution-based unsteady friction model in the FVM to capture real pressure dissipation. The comparison with experimental data proved that the first-order FV scheme with the convolution integral method is highly accurate for computing unsteady friction for sudden valve closures.
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Sonnenberg, H., M. Rustler, M. Riechel, N. Caradot, P. Rouault, and A. Matzinger. "Best data handling practices in water-related research." Water Practice and Technology 8, no. 3-4 (September 1, 2013): 390–98. http://dx.doi.org/10.2166/wpt.2013.039.
Повний текст джерелаАнотація:
Data play an important role in water-related research. Based on experiences in data collection and data processing in water-related research this paper proposes – both from a computer scientist's and an environmental engineer's point of view – a set of rules for data handling: Rule 1: Protect raw data; Rule 2: Save metadata; Rule 3: Use databases; Rule 4: Separate data from processing; Rule 5: Use programming; Rule 6: Avoid redundancy; Rule 7: Be transparent; Rule 8: Use standards and naming conventions. Applying these rules (i) increases the quality of data and results, (ii) allows to prepare data for long-term usage and make data accessible to different people, (iii) makes data processing transparent and results reproducible, and (iv) saves – at least in the long run – time and effort. With this contribution the authors would like to start a discussion about best data handling practices and present a first checklist of data handling and data processing for practitioners and researchers working in the water sector.
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Afsharmanesh, M., T. A. Scott, and F. G. Silversides. "A comparison of grinding processes and wet feeding of wheat-based diets on AME, production, and gastrointestinal tract development of broiler chicks." Canadian Journal of Animal Science 86, no. 2 (June 1, 2006): 255–61. http://dx.doi.org/10.4141/a05-072.
Повний текст джерелаАнотація:
This experiment studied the effect of grind mill type [hammer (HM) or attrition (AM)], grind size (5.6 mm 4.8 mm, and 2.4 mm) and wheat type [Durum or Hard Red Spring (HRS)] on the performance, energy retention (AME), and the gut development of broilers fed these diets with or without 1.2 g water-1 g dry feed added. Twenty-four dietary treatments (2 grind types × 3 grind sizes × 2 wheat types × wet or dry feeding) were each fed to four cages of six male broilers from 1 to 17 d of age. Wet diets were prepared daily. Feeding diets with water increased 17 d body weight and feed intake of broilers compared with feeding the diets dry. Body weight and feed intake of broilers fed the HM diets were greater than those of broilers fed diets containing wheat processed by AM. Feed intake and FCR with HRS-based diets were higher than those for Durum-based diets. The AME for Durum was higher than for HRS and the ME efficiency (kcal g-1 BW) was greater, indicating a lower efficiency. The AME intake of HM ground wheat was higher than for that for wheat ground with the AM. The type of grinding, the wheat type, and the addition of water all affected the length and weight of the digestive system, likely through their effects on the rate of water absorption and passage through the gut. Particle size did not affect any measurement. Hammer milling produced a uniform particle size and less fines and may be better suited for processing wheat in broiler diets. Key words: Broiler, wheat, wet feeding, AME, gut development
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Gunawan, I., and S. Alawiyah. "Terrain Correction in Gravity Data Processing using Hybrid Land Survey and Shuttle Radar Topography Mission Digital Elevation Model: A Case Study in Mount Pandan, Indonesia." Journal of Physics: Conference Series 2243, no. 1 (June 1, 2022): 012012. http://dx.doi.org/10.1088/1742-6596/2243/1/012012.
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Abstract A clean corrected complete Bouger anomaly would perform reasonable geological subsurface interpretation. As a part of the processing phase, the terrain correction has a significant influence. Since the terrain correction entangles a vast area, it is not easy to fulfill with land survey. Our study aimed to apply an SRTM DEM in addition to land survey data to overcome a satisfactory terrain correction. We have applied the SRTM data to calculate the terrain correction for the outer zone (i.e., D to M) using the Hammer method. In Mount Pandan, Indonesia, we have set this method to generate a complete Bouguer anomaly as a case study. The terrain correction in the outer zone has corrected the gravity anomaly up to 14.74 mGal. The result shows that the hybrid elevation data may provide sufficient terrain correction in gravity data processing for practical geological subsurface interpretation.
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Zhaochunlei. "Research on big data processing of water conservancy automation." IOP Conference Series: Earth and Environmental Science 768, no. 1 (May 1, 2021): 012114. http://dx.doi.org/10.1088/1755-1315/768/1/012114.
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