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Paul, Sumit, Wolfgang Legner, Angelika Krenkow, Gerhard Müller, Thierry Lemettais, Francois Pradat e Delphine Hertens. "Chemical Contamination Sensor for Phosphate Ester Hydraulic Fluids". International Journal of Aerospace Engineering 2010 (2010): 1–9. http://dx.doi.org/10.1155/2010/156281.
Testo completoAbstract (sommario):
The paper deals with chemical contamination monitoring in phosphate-ester-based hydraulic fluids using nondispersive infrared (NDIR) optical absorption. Our results show that NDIR monitoring allows detecting the take-up of water into such fluids and their hydrolytic disintegration as these become additionally stressed by Joule heating. Observations on the O–H stretching vibration band (3200–3800 ) are used for determining the free water content (0–1.5%) and the Total Acid Number (0–1 mgKOH/g). Both quantities can be assessed by monitoring the strength and the asymmetry of the O–H vibration band with regard to the free water absorption band centred around 3500 . As such optical parameters can be assessed without taking fluid samples from a pressurised hydraulic system, fluid degradation trends can be established based on regular measurements, before irreversible damage to the fluid has occurred. Therefore maintenance actions can be planned accordingly, which is very important for the airline, as unscheduled maintenance disturbs the flights organisation and often generates money loss.
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Aliboyev, B. A. "Reliability of tractor hydraulic systems in the context of purity of power fluid". Traktory i sel hozmashiny 82, n. 6 (15 giugno 2015): 26–29. http://dx.doi.org/10.17816/0321-4443-65416.
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The article is dedicated to review and analysis of control and estimation methods of power fluid purity in order to provide reliability of tractor hydraulic systems. It highlights the results of experimental studies concerning contamination of hydraulic system fluids. Comparative analysis of foreign standards of hydraulic system fluids control is performed.
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Majdan, R., Z. Tkáč, B. Stančík, R. Abrahám, I. Štulajter, P. Ševčík e M. Rášo. "Elimination of ecological fluids contamination in agricultural tractors". Research in Agricultural Engineering 60, Special Issue (30 dicembre 2014): S9—S15. http://dx.doi.org/10.17221/27/2013-rae.
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This contribution presents the elimination of pollution for ecological fluids of UTTO (universal tractor transmission oils) type in agricultural tractors. The common oil filling of the transmission and hydraulic system is polluted by residues of old fillings from attachments such as ploughs, trailers, etc. In the tractor Zetor Forterra 114 41, a newly developed synthetic ecological fluid HEPR (VDMA 24568) was applied. The oil showed pollution limits after completing 900 engine hours. For this reason, a filtration device was designed to clean mainly biodegradable fluids UTTO. On the basis of fluid application evaluation and performed filtration, it can be concluded that a simple and affordable filtration system reduces the concentration of the most dangerous contamination particles (particles lager than 14 μm) by up to 30%.
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Main, B. G. "Explosion Hazards in Offshore Motion Compensators". Proceedings of the Institution of Mechanical Engineers, Part A: Power and Process Engineering 199, n. 4 (novembre 1985): 229–35. http://dx.doi.org/10.1243/pime_proc_1985_199_029_02.
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Auto-ignition data for phosphate ester hydraulic fluids and explosion initiators in high pressure hydraulic/pneumatic motion compensators are reviewed. Data obtained in this study highlight the potential increased danger due to contamination of fire-resistant fluids.
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SCHOLZ, Dieter. "Routes of Aircraft Cabin Air Contamination from Engine Oil, Hydraulic and Deicing Fluid". INCAS BULLETIN 14, n. 1 (7 marzo 2022): 153–70. http://dx.doi.org/10.13111/2066-8201.2022.14.1.13.
Testo completoAbstract (sommario):
Purpose: This paper discusses potential contamination of the air in passenger aircraft cabins. It gives an overview of cabin air contamination basics. It further names possible contamination sources and possible routes of contamination. – Methodology: Evidence follows from a review of material found on the Internet and from the documentation of a visit to an aircraft recycling site. Parts were retrieved at the site and investigated later with more time. – Findings: Jet engine seals leak oil in small quantities. Metallic nanoparticles are found in the oil and have been detected in human fatty tissue of aviation workers. It has been observed that the potable water on board can also be contaminated. Oil traces have been found in bleed ducts, air conditioning components, and in air conditioning ducts. Deicing fluid and hydraulic fluid can find their way into the air conditioning system via the APU air intake. Fuel and oil also leak down onto the airport surfaces. These fluids can be ingested by the engine from the ground and can enter the air conditioning system from there. Entropy is the law of nature that states that disorder always increases. This is the reason, why it is impossible to confine engine oil and hydraulic fluids to their (predominantly) closed aircraft systems. This is why engine oil with metal nanoparticles hydraulic fluids, and deicing fluids eventually can go everywhere and finally into the human body. – Research Limitations: No measurements have been made. – Practical Implications: Awareness and prevention of contaminated cabin air can protect passengers and crew. – Social Implications: The exposure of contaminated cabin air provides a basis for a general discussion and shows that people should be alerted and need to act. New technologies need to be implemented such as a bleed free architecture. – Originality: This paper shows many original images of contaminated parts and air ducts between engine compressor and cabin air outlet. Own observations are combined with similar observations found in literature and online. The collected evidence is visualized in a diagram showing the routes of possible aircraft cabin air (and water) contamination.
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Kučera, Marián, Zdeněk Aleš, Jan Mareček e Pavel Máchal. "Effect of Contamination on the Lifetime of Hydraulic Oils and Systems". Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 65, n. 4 (2017): 1205–12. http://dx.doi.org/10.11118/actaun201765041205.
Testo completoAbstract (sommario):
The extensions of service‑lives regarding hydraulic fluids is gaining prominence due to several considerations including environmental pollution, conservation of natural resources and the economic benefits associated with extended service‑life. The presented methods for testing the durability and oxidation stabilities of hydraulic fluids can be simultaneously used in two ways. Firstly for comparing different hydraulic biooils and for selecting more adequate oils with higher oxidation stabilities and longer service lifetimes and secondly for the development of a prognostic model for an accurate prediction of an oil’s condition and its remaining useful lifetime, which could help to extend the service life of the oil without concerns about damaging the equipment.
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Owens, E. H., G. H. Smith e I. A. Reading. "An instrument for measurement of water contamination in hydraulic fluids". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 221, n. 2 (febbraio 2007): 167–70. http://dx.doi.org/10.1243/09544070jauto457.
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Theissen, Heinrich W., David G. Holt, David K. Wills e S. W. Dean. "Effects of Contamination of Biobased Hydraulic Fluids with Mineral Oil". Journal of ASTM International 6, n. 1 (2009): 101598. http://dx.doi.org/10.1520/jai101598.
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Hunt, T. M. "Particle contamination and filtration of hydraulic fluids, lubricants and fuels". Tribology International 21, n. 5 (ottobre 1988): 297–98. http://dx.doi.org/10.1016/0301-679x(88)90012-6.
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Janoško, I., T. Polonec e S. Lindák. "Performance parameters monitoring of the hydraulic system with bio-oil". Research in Agricultural Engineering 60, Special Issue (30 dicembre 2014): S37—S43. http://dx.doi.org/10.17221/32/2013-rae.
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In environmental terms, hydraulic fluids used in the hydraulic system of municipal vehicles represent problems related to a potential leakage from the system into the environment and the subsequent contamination of groundwater and soil. More environment-friendly way is to use green hydraulic fluids that are biodegradable in accidents. This paper aims to investigate the possibilities of biodegradable oil application and its adaptation in the hydraulic systems of municipal vehicles by monitoring the impact of the bio-oil Mobil EAL 46 ESSO on the performance parameters as flow, efficiency, durability, etc. Hydraulic pump revolutions were measured using a non-contact sensor based on the principle of magnetic induction change. Method of tightness monitoring was used to achieve results for functionality and wear of the hydraulic system. During 600 h of the test period no significant deterioration of performance parameters was detected. Results are useful for companies involved in waste collection.
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Helwig, Andreas, Gerhard Müller e Sumit Paul. "Health Monitoring of Aviation Hydraulic Fluids Using Opto-Chemical Sensor Technologies". Chemosensors 8, n. 4 (13 dicembre 2020): 131. http://dx.doi.org/10.3390/chemosensors8040131.
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Passenger safety requires that in commercial airplanes hydraulic actuators be powered by fire-resistant hydraulic fluids. As a downside, such fluids are hygroscopic which means that these tend to accumulate humidity from the environment and that the dissolved humidity tends to produce acidity which can corrode all kinds of metallic components inside a hydraulic system. As such damage in safety-critical subsystems is hard to localize and expensive to repair, sensor technologies are required which allow the state of water contamination and fluid degradation to be routinely checked and necessary maintenance actions to be scheduled in a way that causes minimum flight interruptions. The paper reviews progress that has been made in developing such sensor systems and in commissioning these into practical flight operation. Sensor technologies that proved optimally adapted to this purpose are multi-channel non-dispersive (NDIR) systems working in the mid-infrared range. Additional options concern optical absorption sensors working in the near-infrared and visible ranges as well as fluorescence sensors.
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Khan, Thawhid, Matthew Broderick e Chris M. Taylor. "Investigating the industrial impact of hydraulic oil contamination on tool wear during machining and the development of a novel quantification methodology". International Journal of Advanced Manufacturing Technology 112, n. 1-2 (22 novembre 2020): 589–600. http://dx.doi.org/10.1007/s00170-020-06370-y.
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AbstractWater based metalworking fluids (MWFs) commonly used for cooling and lubrication during machining are utilised in combination with cutting tools, work materials, fixtures and machine tools. However, they are an often overlooked component of the overall machining process, despite the fact that in some reported cases MWF costs were twice that of tooling costs. During its life cycle in a machine tool, the MWF is exposed to changes due to a range of factors which impact its quality and longevity. The key process variables (KPVs) reviewed in this study are MWF concentration, hydraulic (tramp) oil, solid particulates, water quality, MWF pH and microbial contamination. The aim of the present work is to highlight these KPVs which impact machining quality and health and safety, and to present industrially applicable measurement, monitoring and control (MMC) methods and techniques. This review is supported by a machining case study which demonstrates the impact of a single KPV—hydraulic (tramp) oil on MWF quality and machining output, and the need for applying MMC methods. Continuous hydraulic (tramp) oil contamination into the cutting fluid can cause tool life and wear to vary by 70%. A novel quantification methodology with gas chromatography was developed in this study to quantitatively measure hydraulic (tramp) oil contamination present within MWF and verified through experiments. The study overall highlights the need to apply a strict maintenance programme to increase the MWF lifetime and maintain performance for improved production, experimental process control and operator health and safety.
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Mouallem, Carlos, Wilson Trigueiro de Sousa, Ivo Eyer Cabral e Adilson Curi. "Perspectives for use of hydraulic fracturing in oil and gas production". Rem: Revista Escola de Minas 67, n. 4 (dicembre 2014): 373–78. http://dx.doi.org/10.1590/0370-44672014670168.
Testo completoAbstract (sommario):
Hydraulic fracturing emerges currently, all over the world, as one of the more strategic techniques used by companies in the oil exploitation sector. This technique is characterized by its high productivity and profit in relation to conventional methods of hydrocarbon exploitation. However, in many countries, as is the case of Brazil, there are several divergences considering the employment of this methodology. Many renowned researchers attest that there are several irreversible environmental impacts generated by the use of this methodology. Among the main environmental impacts are the risk of groundwater level contamination, the risk of surface subsidence, and the risk of the environment contamination with fluids used in the process of the oil and gas extraction.
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Martínez-Sánchez, Dilan Arturo, e Giovanny Jiménez Díaz. "Hydraulic fracturing considerations: Insights from analogue models, and its viability in Colombia". Earth Sciences Research Journal 23, n. 1 (1 gennaio 2019): 5–15. http://dx.doi.org/10.15446/esrj.v23n1.69760.
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Fracking is being considered around the world as a potential method in the hydrocarbons extraction given the increase of production in USA and Canada during the last years with its implementation. The most criticized feature of the technique of fracking is the contamination of underground waters by fluids connected through the generated and/or pre-existing fractures. This work evaluates the viability of fracking in Colombian territory based in the study of the analogue models, considering the elastic properties of the reservoir rocks using gelatin, sand and clay that apply scaled pressure (lithostatic pressure to scale). The gelatin is used to simulate the reservoir zone, the clay will simulate one sail and the sand will simulate reservoir rocks of underground water. As a result seven different models were generated. There were simulated as 1) the anisotropy presence, 2) the rock sail presence, and 3) the injection groove of fluids in the pipeline. The completed models show that the required distance between the unconventional reservoir and underground waters to avoid contamination by fluids is ~200 m, also between the hydraulic fracturing point and the faults that connect with the shallows area is ~350 m, and it is suggested to study in detail the permeability of both: nearby faults and the rock sail. Two Colombian basins (Magdalena Midland Valley and Llanos) were taken as the main base to analyze the assessment of fracking according to the previously mentioned results, concluding that it is viable particularly in areas like Llanos Basin and with some precautions in similar zones to Magdalena Midland Valley Basin.
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Dakheel Almaliki, Alaa J., Mohammed J. K. Bashir e Juan F. Llamas Borrajo. "Appraisal of groundwater contamination from surface spills of fluids associated with hydraulic fracturing operations". Science of The Total Environment 815 (aprile 2022): 152949. http://dx.doi.org/10.1016/j.scitotenv.2022.152949.
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Pichtel, John. "Oil and Gas Production Wastewater: Soil Contamination and Pollution Prevention". Applied and Environmental Soil Science 2016 (2016): 1–24. http://dx.doi.org/10.1155/2016/2707989.
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During oil and natural gas production, so-called “produced water” comprises the largest byproduct stream. In addition, many oil and gas operations are augmented via injection of hydraulic fracturing (HF) fluids into the formation. Both produced water and HF fluids may contain hundreds of individual chemicals, some known to be detrimental to public health and the environment. Oil and gas production wastewater may serve a range of beneficial purposes, particularly in arid regions, if managed correctly. Numerous treatment technologies have been developed that allow for injection, discharge to the land surface, or beneficial reuse. Although many papers have addressed the effects of oil and gas production wastewater (OGPW) on groundwater and surface water quality, significantly less information is available on the effects of these fluids on the soil resource. This review paper compiles fundamental information on numerous chemicals used and produced during oil and gas development and their effects on the soil environment. Additionally, pollution prevention technologies relating to OGPW are presented. An understanding of the effects of OGPW on soil chemical, physical, and biological properties can provide a foundation for effective remediation of OGPW-affected soils; additionally, sustainable reuse of oil and gas water for irrigation and industrial purposes may be enhanced.
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Negrini, Daniela, Alberto Passi, Katia Bertin, Federica Bosi e Helge Wiig. "Isolation of pulmonary interstitial fluid in rabbits by a modified wick technique". American Journal of Physiology-Lung Cellular and Molecular Physiology 280, n. 5 (1 maggio 2001): L1057—L1065. http://dx.doi.org/10.1152/ajplung.2001.280.5.l1057.
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Interstitial fluid protein concentration (Cprotein) values in perivascular and peribronchial lung tissues were never simultaneously measured in mammals; in this study, perivascular and peribronchial interstitial fluids were collected from rabbits under control conditions and rabbits with hydraulic edema or lesional edema. Postmortem dry wicks were implanted in the perivascular and peribronchial tissues; after 20 min, the wicks were withdrawn and the interstitial fluid was collected to measure Cprotein and colloid osmotic pressure. Plasma, perivascular, and peribronchial Cproteinvalues averaged 6.4 ± 0.7 (SD), 3.7 ± 0.5, and 2.4 ± 0.7 g/dl, respectively, in control rabbits; 4.8 ± 0.7, 2.5 ± 0.6, and 2.4 ± 0.4 g/dl, respectively, in rabbits with hydraulic edema; and 5.1 ± 0.3, 4.3 ± 0.4 and 3.3 ± 0.6 g/dl, respectively, in rabbits with lesional edema. Contamination of plasma proteins from microvascular lesions during wick insertion was 14% of plasma Cprotein. In control animals, pulmonary interstitial Cprotein was lower than previous estimates from pre- and postnodal pulmonary lymph; furthermore, although the interstitium constitutes a continuum within the lung parenchyma, regional differences in tissue content seem to exist in the rabbit lung.
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Llewellyn, Garth T., Frank Dorman, J. L. Westland, D. Yoxtheimer, Paul Grieve, Todd Sowers, E. Humston-Fulmer e Susan L. Brantley. "Evaluating a groundwater supply contamination incident attributed to Marcellus Shale gas development". Proceedings of the National Academy of Sciences 112, n. 20 (4 maggio 2015): 6325–30. http://dx.doi.org/10.1073/pnas.1420279112.
Testo completoAbstract (sommario):
High-volume hydraulic fracturing (HVHF) has revolutionized the oil and gas industry worldwide but has been accompanied by highly controversial incidents of reported water contamination. For example, groundwater contamination by stray natural gas and spillage of brine and other gas drilling-related fluids is known to occur. However, contamination of shallow potable aquifers by HVHF at depth has never been fully documented. We investigated a case where Marcellus Shale gas wells in Pennsylvania caused inundation of natural gas and foam in initially potable groundwater used by several households. With comprehensive 2D gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOFMS), an unresolved complex mixture of organic compounds was identified in the aquifer. Similar signatures were also observed in flowback from Marcellus Shale gas wells. A compound identified in flowback, 2-n-Butoxyethanol, was also positively identified in one of the foaming drinking water wells at nanogram-per-liter concentrations. The most likely explanation of the incident is that stray natural gas and drilling or HF compounds were driven ∼1–3 km along shallow to intermediate depth fractures to the aquifer used as a potable water source. Part of the problem may have been wastewaters from a pit leak reported at the nearest gas well pad—the only nearby pad where wells were hydraulically fractured before the contamination incident. If samples of drilling, pit, and HVHF fluids had been available, GCxGC-TOFMS might have fingerprinted the contamination source. Such evaluations would contribute significantly to better management practices as the shale gas industry expands worldwide.
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Máchal, Pavel, Radoslav Majdan, Zdenko Tkáč, Bohuslav Stančík, Rudolf Abrahám, Ivan Štulajter, Peter Ševčík e Milan Rášo. "Design and verification of additional filtration for the application of ecological transmission and hydraulic fluids in tractorc". Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 61, n. 5 (2013): 1305–11. http://dx.doi.org/10.11118/actaun201361051305.
Testo completoAbstract (sommario):
This contribution presents the design and function verification of additional filtration. It is intended for the common transmission and hydraulic oil filling of tractors. The main role of this filtration concept is to ensure a high level of oil cleanness as a condition for the application of ecologic fluids in tractors. The next one is to decrease the wear of lubricated tractor components, the degradation of oil and eventually to extend the interval of oil change. The designed additional filtering is characterized by ease installation through the use of quick couplings and hoses to the external hydraulic circuit. Therefore, the filtration is suitable for various tractor types. Filter element has been designed with the filter ability 1micron and the ability to separate to 0.5 dm3 of water from oil. Function of additional filtration was verified during the 150 engine hours of tractor operation. During this time period the oil contamination was evaluated on the basis of chemical elements content such as Fe, Cu, Si, Al, Ni, Mo and Cr. The additive concentration was evaluated on the basis of chemical elements content such as Ca, P and Zn. During the test operation of tractor the concentration decrease of chemical elements reached the values 25.53 % (Fe), 23.53 % (Si), 25 % (Al) and 5.5 % (Cu). The decrease of additive concentration reached only medium level (6.6 %). Therefore, the designed additional filtration doesn’t remove additives from oil. Based on the evaluation of the content of chemical elements (that representing contamination and additives), we can say that the designed filtering method is suitable for use in agricultural tractors.
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Almaliki, Alaa Jasim Dakheel, Mohammed J. K. Bashir e Juan F. Llamas Borrajo. "The Impact of Climate Change and Soil Classification on Benzene Concentration in Groundwater Due to Surface Spills of Hydraulic Fracturing Fluids". Water 14, n. 8 (8 aprile 2022): 1202. http://dx.doi.org/10.3390/w14081202.
Testo completoAbstract (sommario):
Hydraulic fracturing drilling technology can cause a high risk of surface spill accidents and thus water contamination. Climate change together with the high water demand and rapid increase in industrial and agricultural activities are valued reasons why we should all care about the availability of water resources and protect them from contamination. Hence, the purpose of this study is to estimate the risk associated with a site contaminated with benzene from oil spillage and its potential impact on groundwater. This study focused on investigating the impact of soil variability and water table depth on groundwater contamination. Temperature-dependent parameters, such as soil water content and the diffusion of pollutants, were considered as key input factors for the HYDRUS 1D numerical model to simulate benzene migration through three types of soil (loamy, sandy clay loam, and silt loam) and evaluate its concentration in the water aquifer. The results indicated that an anticipated increase in earth’s average surface temperature by 4 °C due to climate change could lead to a rise in the level of groundwater pollution in the study area by 0.017 mg/L in loamy soil, 0.00046 mg/L in sandy clay loam soil, and 0.00023 mg/L in silt loam soil. It was found that climate change can reduce the amount of benzene absorbed from 10 to 0.07% in loamy soil, 14 to 0.07% in sandy clay loam soil, and 60 to 53% in silt loam soil. The results showed that the soil properties and solute characteristics that depend on the temperature have a major and important role in determining the level of groundwater pollutants.
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Pochi, Daniele, Renato Grilli, Laura Fornaciari, Monica Betto, Stefano Benigni e Roberto Fanigliulo. "Bench Testing of Sensors Utilized for In-Line Monitoring of Lubricants and Hydraulic Fluids Properties". Sensors 21, n. 24 (8 dicembre 2021): 8201. http://dx.doi.org/10.3390/s21248201.
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This work reports the results of a study on the behaviour of five sensors recently developed for oil conditions monitoring, installed in-line in an experimental test rig for lubricants. The tests were carried out on seven oils of different origins (one synthetic ester, two bio-based synthetic esters, four vegetable oils) and use (two UTTOs and five hydraulic oils), under controlled working conditions, according to a specially designed test method. At first, the study concerned the identification of the conditions for the correct sensors’ installation. Then, the tests started applying to the fluids severe work cycles intended to accelerate oil ageing. The data of viscosity, permittivity, relative humidity, electric conductivity, particle contamination, and ferro-magnetic particles provided by the sensors were compared to the results of laboratory analyses made on oil samples taken during the tests with the aim of verifying the sensors measurements accuracy and reliability and selecting the more suitable ones to in-line oil conditions monitoring, in the perspective of introducing them also in field applications, e.g., on agricultural tractors, for preventing damages due to oil deterioration, and in managing the machine maintenance.
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Zhang, Lifu, Michael Tice e Berna Hascakir. "A Laboratory Study of the Impact of Reinjecting Flowback Fluids on Formation Damage in the Marcellus Shale". SPE Journal 25, n. 02 (21 gennaio 2020): 788–99. http://dx.doi.org/10.2118/195336-pa.
Testo completoAbstract (sommario):
Summary Reuse of flowback water in hydraulic fracturing is usually used by industry to reduce consumption, transportation, and disposal cost of water. However, because of complex interactions between injected water and reservoir rocks, induced fractures may be blocked by impurities carried by flowback and mineral precipitation by water/rock interactions, which causes formation damage. Therefore, knowledge of flowback water/rock interactions is important to understand the changes within the formation and effects on hydraulic fracturing performance. This study focuses on investigating flowback water/rock interactions during hydraulic fracturing in Marcellus Shale. Simple deionized water (DI)/rock interactions and complicated flowback water/rock interactions were studied under static and dynamic conditions. In static experiments, crushed reservoir rock samples were exposed to water for 3 weeks at room condition. In the dynamic experiment, continuous water flow interacted with rock samples through the coreflooding experimental system for 3 hours at reservoir condition. Before and after experiments, rock samples were characterized to determine the change on the rock surfaces. Water samples were analyzed to estimate the particle precipitation tendency and potential to modify flow pathway. Surface elemental concentrations, mineralogy, and scanning electron microscope (SEM) images of rock samples were characterized. Ion contents, particle size, total dissolved solids (TDS), and zeta-potential in the water samples were analyzed. After flowback water/rock interaction, the surface of the rock sample shows changes in the compositions and more particle attachment. In produced water, Na, Sr, and Cl concentrations are extremely high because of flowback water contamination. Water parameters show that produced water has the highest precipitation tendency relative to all water samples. Therefore, if flowback water without any treatment is reused in hydraulic fracturing, formation damage is more likely to occur from blockage of pores. Flowback water management is becoming very important due to volumes produced in every hydraulic fracturing operation. Deep well injection is no longer a favorable option because it results in disposal of high volumes of water that cannot be used for other purposes. A second option is the reuse of waste water for fracturing purposes, which reduces freshwater use significantly. However, the impurities present in flowback water may deteriorate the fracturing job and reduce or block the hydraulic fracturing apertures. This study shows that a simple filtration process applied to the flowback water allows for reinjection of the flowback water without further complication to the water/rock interaction, and does not cause significant formation damage in the fractures.
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Ahmed, Amna, Teresa Zhu e Amna Majeed. "Taking the hydro out of hydrofracturing: Application of ultra-light weight proppants to cryogenic liquid nitrogen as a fracturing fluid". University of Ottawa Science Undergraduate Research Journal 1 (23 agosto 2018): 57. http://dx.doi.org/10.18192/osurj.v1i1.3711.
Testo completoAbstract (sommario):
In the last decade, hydraulic fracturing has rapidly gained popularity worldwide, emerging as the leading method of natural gas extraction in the United States. However, the practice remains controversial due to its contribution to greenhouse gas emissions and the contamination of freshwater used in fracturing fluids. Although waterless fracturing fluids have been developed, including those using N2, CO2, oil, and alcohol, their application has been limited largely due to reduced fracturing power. Recent research has demonstrated that cryogenic nitrogen may prove a viable alternative, if this issue is properly addressed. Addition of durable, lightweight proppants is one way to increase fracturing power. This study aims to investigate the effect of proppant addition on the fracturing capabilities of cryogenic nitrogen. Three ultra-lightweight proppants will be combined with liquid nitrogen and fracturing power will be measured using triaxial stress tests. This novel approach has not yet been explored and will open more avenues of research into sustainable and efficient fracturing using cryogenic nitrogen.
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Song, Charles C. S., e Mingshun Yuan. "A Weakly Compressible Flow Model and Rapid Convergence Methods". Journal of Fluids Engineering 110, n. 4 (1 dicembre 1988): 441–45. http://dx.doi.org/10.1115/1.3243575.
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A weakly compressible flow model for small Mach number flows is applied to the computation of steady and unsteady inviscid flows. The equations of continuity and motion are decoupled from the energy equation, but, unlike the equations for incompressible fluids, these equations retain the ability to represent rapidly changing flows such as hydraulic transients and hydroacoustics. Two methods to speed up the process of convergence when an explicit method is used to calculate steady incompressible flows are proposed. The first method which is quite similar to the artificial compressiblity method is to assume an arbitrarily small sound speed (equivalent to large Mach number) to speed up the convergence. Any positive finite number may be used for M. One disadvantage of this method is the contamination of the steady flow solution by acoustic noise that may reverberate in the flow field for some time after the steady flow has been essentially established. The second method is based on the concept of valve stroking or boundary control. Certain boundary stroking functions that will unify the hydroacoustic and hydrodynamic processes can be found by using the inverse method of classical hydraulic transients. This method yields uncontaminated steady flow solution very rapidly independent of the Mach number.
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Peng, Weihong, Menglin Du, Feng Gao, Xuan Dong e Hongmei Cheng. "A New Analysis Model for Potential Contamination of a Shallow Aquifer from a Hydraulically-Fractured Shale". Energies 11, n. 11 (1 novembre 2018): 3010. http://dx.doi.org/10.3390/en11113010.
Testo completoAbstract (sommario):
Hydraulic fracturing (HF) is widely used in shale gas development, which may cause some heavy metals release from shale formations. These contaminants could transport from the fractured shale reservoirs to shallow aquifers. Thus, it is necessary to assess the impact of pollution in shallow aquifers. In this paper, a new analysis model, considering geological distributions, discrete natural fractures (NFs) and faults, is developed to analyze the migration mechanism of contaminants. Furthermore, the alkali erosion of rock caused by high-pH drilling of fluids, is considered in this paper. The numerical results suggest that both NFs and alkali erosion could reduce the time required for contaminants migrating to aquifers. When NFs and alkali erosion are both considered, the migration time will be shortened by 51 years. Alkali erosion makes the impact of NFs, on the contaminant migration, more significant. The migration time decreases with increasing pH values, while the accumulation is on the opposite side. Compared with pH 12.0, the migration time would be increased by 45 years and 29 years for pH 11.0 and 11.5, respectively. However, the migration time for pH 12.5 and 13.0 were found to be decreased by 82 years and 180 years, respectively. Alkali erosion could increase the rock permeability, and the elevated permeability would further enhance the migration velocity of the contaminants, which might play a major role in assessing the potential contamination of shallow aquifers.
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Osenbrück, Karsten, Eva Blendinger, Carsten Leven, Hermann Rügner, Michael Finkel, Natalia Jakus, Hartmut Schulz e Peter Grathwohl. "Nitrate reduction potential of a fractured Middle Triassic carbonate aquifer in Southwest Germany". Hydrogeology Journal 30, n. 1 (7 dicembre 2021): 163–80. http://dx.doi.org/10.1007/s10040-021-02418-9.
Testo completoAbstract (sommario):
AbstractNitrate reduction constitutes an important natural mechanism to mitigate the widespread and persistent nitrate contamination of groundwater resources. In fractured aquifers, however, the abundance and accessibility of electron donors and their spatial correlation with groundwater flow paths are often poorly understood. In this study, the nitrate reduction potential of a fractured carbonate aquifer in the Upper Muschelkalk of SW Germany was investigated, where denitrification is due to the oxidation of ferrous iron and reduced sulfur. Petrographical analyses of rock samples revealed concentrations of syn-sedimentary and diagenetically formed pyrite ranging from 1 to 4 wt.% with only small differences between different facies types. Additional ferrous iron is available in saddle dolomites (up to 2.6 wt.%), which probably were formed by tectonically induced percolation of low-temperature hydrothermal fluids. Borehole logging at groundwater wells (flowmeter, video, gamma) indicates that most groundwater flow occurs along karstified bedding planes partly located within dolomites of the shoal and backshoal facies. The high porosity (15–30%) of these facies facilitates molecular diffusive exchange of solutes between flow paths in the fractures and the reactive minerals in the pore matrix. The high-porosity facies together with hydraulically active fractures featuring pyrite or saddle dolomite precipitates constitute the zones of highest nitrate reduction potential within the aquifer. Model-based estimates of electron acceptor/donor balances indicate that the nitrate reduction potential protecting water supply wells increases with increasing porosity of the rock matrix and decreases with increasing hydraulic conductivity (or effective fracture aperture) and spacing of the fracture network.
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Ułanowicz, Leszek, Grzegorz Jastrzębski, Michał Jóźko, Ryszard Sabak e Paweł Szczepaniak. "Hydraulic plunger pump contamination sensitivity evaluation". Journal of KONBiN 48, n. 1 (1 dicembre 2018): 371–83. http://dx.doi.org/10.2478/jok-2018-0061.
Testo completoAbstract (sommario):
Abstract The correct operation of the hydraulic pump and achieving the assumed durability depends on the purity of the used working fluid. The research paper discusses a method for evaluating the contamination sensitivity of a hydraulic plunger pump. The theoretical grounds for evaluating the contamination sensitivity of hydraulic plunger pumps of a hydraulic drive based on the contamination sensitivity factor were presented. An example of evaluating contamination sensitivity of an NP-34M hydraulic plunger pump was discussed.
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Cozzens, D. A., P. D. Rao, W. W. Olson, J. W. Sutherland e J. Mark Panetta. "An Experimental Investigation into the Effect of Cutting Fluid Conditions on the Boring of Aluminum Alloys". Journal of Manufacturing Science and Engineering 121, n. 3 (1 agosto 1999): 434–39. http://dx.doi.org/10.1115/1.2832700.
Testo completoAbstract (sommario):
Boring tests were conducted on aluminum alloys to investigate the effects of cutting fluid on machining performance. Statistically designed experiments were used to examine the role of such process variables as tool geometry, cutting conditions, work material, cutting fluid presence, cutting fluid concentration, and hydraulic oil contamination of cutting fluid. Responses for the boring tests were surface texture, forces, and observed built-up edge (BUE). The results indicate that the cutting fluid presence, oil concentration, and hydraulic oil contamination do not play a significant role in process performance under the conditions tested.
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Dusa, Petru, Eugen Purice, Radu Lupascu, Iustina Ripanu e Gabriel Fandarac. "Configuring a system for hydraulic oil contamination management". MATEC Web of Conferences 178 (2018): 04008. http://dx.doi.org/10.1051/matecconf/201817804008.
Testo completoAbstract (sommario):
Through contamination, we can understand anything foreign to a hydraulic system. In this paper we only refer to particle contamination. Analyzing and optimizing processes with regard to component cleanliness and fluid purity is the target of contamination management. The paper proposes a conceptual installation solution for the use of particle counters in order to optimize the measurement process. There is also a way of using the facility within a contamination management system.
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Jozef Krilek, Jozef, Jan Kovach, Tomash Kuvik e Lucia Dobrotova. "Analysis of the hydraulic oil to drive band sawmill". Scientific Bulletin of UNFU 29, n. 10 (26 dicembre 2019): 89–92. http://dx.doi.org/10.36930/40291018.
Testo completoAbstract (sommario):
Transport and material handling is a sum of technological processes in the wood-processing industry. Hydraulic drives are one of the drive options used as a basic part of the transport – handling machines. Contamination control involves preventing contaminants from entering a hydraulic system and placing filters in strategic locations throughout the system to trap any contaminants to find their way into the fluid. But for critical equipment, a successful contamination control program must also include regular assessment of the hydraulic fluid cleanliness. It must be often done every two to six months or after every 500 or 1,000 hours of operation, depending on the equipment duty cycle, operating environment, and how critical it is to overall operation. Pressure forces in hydraulic drives are transferred to hydraulically-operated devices which also serve to lubricate the elements, displace and remove heat from the system. To increase the service life of hydraulic drives, hydraulic oil must meet individual physical characteristics. To ensure reliability, timely diagnosis of hydraulic oil is required. Some experts also recommend that fluid to be tested immediately after any maintenance event that exposes the hydraulic system to the external environment. This could occur when a hose or other component is replaced or fluid is added to the reservoir. Fluid replenishment can be particularly troublesome because new fluid is notorious for being dirty – often from improper storage and handling practices. The article deals with the methodology of measuring the basic physical properties of hydraulic oil by the respective diagnostic devices directly on the hydraulic drive of the bend saw in the full operation of the machine. The methodology suggested enables making decisions for improvement of the hydraulic oil state.
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Elshahawi, Hani, Mohamed Naguib Hashem, Daniel McKinney, Mario Ardila e Cosan Ayan. "The Power of Real-Time Monitoring and Interpretation in Wireline Formation Testing-Case Studies". SPE Reservoir Evaluation & Engineering 10, n. 03 (1 giugno 2007): 241–50. http://dx.doi.org/10.2118/94708-pa.
Testo completoAbstract (sommario):
Summary Modern wireline formation testers (WFTs) are able to collect a massive amount of data at multiple depths, thus helping to quantify changes in rock and fluid properties along the wellbore, to define hydraulic flow units, and to understand the reservoir architecture. They are being used routinely in a wide range of applications spanning pressure and mobility profiling vs. depth, fluid sampling, downhole fluid analysis (DFA), interval pressure-transient testing (IPTT), and microfracturing. Because of the complex tool strings and the elaborate operational aspects involved in wireline formation testing, success requires detailed upfront planning and procedural design as well as real-time operational and interpretational support. It is becoming increasingly critical for operating and service company experts to remotely monitor and interpret WFT surveys in real time through Web-based systems. The importance of meeting all rock and fluid data-acquisition objectives cannot be overstated, given the high cost of offshore operations and the implications of obtaining false or misleading information. The main objective of real-time monitoring remains to assure that the planned data are acquired according to pre-established procedures and contingency plans. However, even in developed reservoirs, unexpected circumstances arise, requiring immediate response and modifications to the preplanned job procedures. Unexpectedly low or high mobilities, probe plugging, unanticipated fluid types, the presence of multiple phases, and excessive fluid contamination are but a few examples of such circumstances that would require real-time decision making and procedural modifications. Real-time decisions may include acquiring more pressure data points, extending sampling depths to several zones, extending or shortening sampling times, and repeating microhydraulic fracture reopening/closure cycles, as well as real-time permeability, composition, or anisotropy interpretation to determine optimum transient durations. This paper describes several examples of formation tester surveys that have been remotely monitored in real time to ensure that all WFT evaluation objectives are met. The power of real-time monitoring and interpretation will be illustrated through these case studies. Introduction WFT has become a standard part of the evaluation program of most newly drilled wells, but the objectives vary from offshore deepwater exploration and appraisal wells to old cased-hole and development wells later in the life of a field. Given the wide range of applications and combinations, each WFT evaluation program is unique. Some may include only a pressure-gradient survey for reservoir depletion and communication information, whereas others may seek information on the precise nature of the hydrocarbon fluids and water in terms of chemical and physical properties, phase behavior, and commingling tendencies. Cased-hole surveys might look for bypassed hydrocarbon zones or have objectives that could not be achieved during the openhole phase. Regardless of the type of survey performed, understanding the exploration and appraisal or field-development objectives and translating these into acquisition objectives is essential for success. Figs. 1 and 2 schematically illustrate the real-time monitoring concept. Real-time data are viewable by authorized personnel anywhere around the world, thus allowing virtual collaboration between field staff and off-site service- and operating-company experts throughout the operation. This paper includes several examples of WFT surveys that were monitored and supervised in real time. The cases presented span the entire spectrum of WFT applications including pressures, gradients, sampling, downhole fluid analysis (DFA), IPTT, and microfracturing. The power of real time monitoring and interpretation is clearly illustrated by these examples.
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Gunko, Iryna, Mykola Stadnik, Serhiy Shargorodskiy e Volodymyr Rutkevych. "COMPREHENSIVE FILTRATION SYSTEM FOR CLOSED HYDROSYSTEMS OF AGRICULTURAL EQUIPMENT". ENGINEERING, ENERGY, TRANSPORT AIC, n. 1(112) (23 marzo 2021): 113–25. http://dx.doi.org/10.37128/2520-6168-2021-1-13.
Testo completoAbstract (sommario):
The article the issue of increasing the durability and reliability of units of closed hydraulic systems of agricultural equipment by ensuring the purity of the working fluid is considered. The analysis of existing systems of filtration of working liquid for the closed hydraulic systems of the agricultural equipment is resulted. It is noted that the basis of the created and implemented filtration systems are filtration installations in pressure mains, including with automatic washing, which provide filtration fineness up to 50 μm, filter elements which have high strength, reliability and are capable of countercurrent washing at working pressure of hydraulic system. The complex system of filtration of working liquid for the closed hydraulic systems of the agricultural equipment is offered. The filtration system of the working fluid provides for the use of filters with backwash and filtration elements with a slit-like brass wire of round cross section. The total length of the filtration gap of one filtration element with a width of 0.05 mm is 40 m The filter provides passive cleaning technology - countercurrent flushing, as the simplest in design, easy to manufacture and sufficiently efficient and cheap. Feature of the filtration installation is a possibility of washing of its filtration elements by a countercurrent of working liquid. The signal for flushing is the occurrence of a pressure drop on the filter, which can be used to judge the degree of contamination and the readings of manometers installed at the inlet and outlet of a closed hydraulic system of agricultural equipment. It is noted that the developed complex filtration system for closed hydraulic systems of agricultural equipment will increase the reliability of control hydraulics at least twice and reduce costly downtime of agricultural machinery due to failure of sealed elements of hydraulic equipment.
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Hui, Ji, Nie Song-Lin e Bai Xiao-Rong. "Simulation on mechanism of contamination mitigation through Higee and hydrocyclone techniques in fluid power system". Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 232, n. 1 (13 dicembre 2016): 77–93. http://dx.doi.org/10.1177/0954408916684161.
Testo completoAbstract (sommario):
In this study, an innovative Higee hydraulic oil purification device capable of removing the solid particle contaminants and water moisture simultaneously is developed for dealing with the contamination control problem of fluid power systems. The purification device is considered as a combination of two units (hydrocyclone separator and rotating packed bed) according to different separation functions. The mathematical models about the migration regularity and dynamic behavior of different phases have been established, in which discrete phase model model is employed to simulate the solid particles – hydraulic oil separation, and Eulerian model is selected as the multiphase simulation model to simulate the hydraulic oil – water moisture separation. Simulation results demonstrate that the hydrocyclone separator can remove solid particles of 5 to 15 µm, while the rotating packed bed can mitigate water moisture. The results indicate that the developed Higee hydraulic oil purification device can provide an effective and efficient manner for controlling the contamination level of fluid power systems.
34
Kosiba, J., Z. Tkáč, Ľ. Hujo, B. Stančík e I. Štulajter. "The operation of agricultural tractor with universal ecological oil". Research in Agricultural Engineering 59, Special Issue (13 dicembre 2013): S27—S33. http://dx.doi.org/10.17221/48/2012-rae.
Testo completoAbstract (sommario):
This contribution presents the results of the research into the characteristics of ecological oil labelled MOL Farm UTTO Synt in the tractor operating conditions. Biodegradable fluid was applied in the gear and hydraulic circuits of the tractor Zetor Forterra 114 41. The fluid was assessed for contamination and lubrication properties by its effect on the wear of tractor hydraulic pump during the application. The hydraulic pump was removed from the tractor at specified time intervals because of its technical condition relating to the flow efficiency. The measurements were calculated as flow efficiency with minimum environmental impact of oil on the hydraulic pump wear.
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Angelaki, Anastasia, Alkiviadis Dionysidis, Parveen Sihag e Evangelia E. Golia. "Assessment of Contamination Management Caused by Copper and Zinc Cations Leaching and Their Impact on the Hydraulic Properties of a Sandy and a Loamy Clay Soil". Land 11, n. 2 (14 febbraio 2022): 290. http://dx.doi.org/10.3390/land11020290.
Testo completoAbstract (sommario):
Soil hydraulic properties are crucial to agriculture and water management and depend on soil structure. The impact of Cu and Zn cations on the hydraulic properties of sandy and loamy clay soil samples of Central Greece, was investigated in the present study. Metal solutions with increased concentrations were used to contaminate the soil samples and the effect on hydraulic properties was evaluated, demonstrating the innovation of the current study. The soil samples were packed separately into transparent columns and the initial values of hydraulic conductivity, cumulative infiltration, infiltration rate and sorptivity were estimated. In order to evaluate soil adsorption, metal concentrations were measured at the water leachate. After the contamination of the soil samples, the hydraulic properties under investigation were determined again, using distilled water as the incoming fluid; the differences at the hydraulic parameters were observed. After doubling metal concentrations into the incoming solution of loamy clay soil, metal adsorption and the values of the hydraulic parameters increased significantly. Loamy clay soil showed interaction between the clay particles and the positive charge in the incoming fluid, which led to a possible increase in aggregation. Furthermore, aggregation may led to pore generation. Contamination of sandy soil exhibited no impact on aggregation and soil structure. In order to evaluate the differences on the hydraulic properties and soil structure, the experimental points were approximated with two infiltration models.
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Domagała, Mariusz, Hassan Momeni, Joanna Fabiś-Domagała, Grzegorz Filo e Paweł Lempa. "Simulations of Safety Vales for Fluid Power Systems". System Safety: Human - Technical Facility - Environment 1, n. 1 (1 marzo 2019): 670–77. http://dx.doi.org/10.2478/czoto-2019-0085.
Testo completoAbstract (sommario):
AbstractHydraulic power systems are widely used in heavy machinery. Safety of such a systems have a major importance due to the fact that any failure may cause environmental contamination or serious injury. One of the component which protects hydraulic drive systems against excessive rising of working pressure is a safety valve which aim is to maintain pressure in the systems below acceptable level. Pressure control valves which plays important role in a hydraulic systems may have very simple or complex structure. Even in case of the simplest structure of such valve modeling is not an easy task. The new quality in designing hydraulic valves bring CFD method and FSI (Fluid Structure Interaction) methods.
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Hujo, Lubomir, Jozef Nosian, Marcin Zastempowski, Jan Kosiba, Jerzy Kaszkowiak e Matej Michalides. "Laboratory tests of the hydraulic pump operating load with monitoring of changes in the physical properties". Measurement and Control 54, n. 3-4 (2 febbraio 2021): 243–51. http://dx.doi.org/10.1177/0020294020983385.
Testo completoAbstract (sommario):
The present article deals with the physical properties monitoring of the transmission-hydraulic fluid, and changes of those properties due the operating load of the hydraulic pump in laboratory conditions. Tests of the transmission-hydraulic fluid were performed in laboratory conditions with the simulation of the operating load, so as to simulate the real conditions under which hydraulic circuit of the agricultural tractors operates. The universal transmission-hydraulic fluid was subjected to analysis, where the samples of the fluid were taken sequentially according to the chosen methodology at intervals of 250 and 500 h. The results of the present article include the evaluation of the physical properties of the fluid and the flow efficiency change of the hydraulic pump after 250 and 500 h of operation, while simulating the operation load. Based on a laboratory test, we found that after working for 500 h, the dynamic viscosity of the examined hydraulic fluid at 40°C decreased by 2.92 mPa.s and at 100°C decreased by 0.64 mPa.s. When determining the kinematic viscosity of the hydraulic fluid after working for 500 h, we recorded its decrease, namely, at a temperature of 40°C by a value of 3.37 mm2/s and at a temperature of 100°C, its value decreased by 0.77 mm2/s. In the analysis of the test oil samples, we found that the level of water contamination of the hydraulic fluid decreases with increasing number of hours worked. Specifically, the water concentration in the hydraulic fluid decreased by 0.031%. At the same time, we recorded a slight decrease in the flow efficiency of the hydraulic pump, specifically by a value of 0.03% after 500 h worked. After working 500 h, we found that the range of abrasion particles in the transmission-hydraulic fluid is within the prescribed range, which is determined by the standard D6595-00.
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Baryshev, V. I., e V. V. Panov. "Key deterioration factors of hydrostatic bearings of the axial-piston hydraulic machines". Traktory i sel hozmashiny 80, n. 1 (15 gennaio 2013): 34–37. http://dx.doi.org/10.17816/0321-4443-65912.
Testo completoAbstract (sommario):
Formation of porous stoppers in delivery capillaries of hydrostatic bearings and their obliteration are substantiated as secondary factors of bearings deterioration under the impact of working fluids contaminations. Findings of the laboratory investigations are given.
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Pimonov, Igor, Igor Pohorilyi e Maksim Fedyuchkov. "Establishment of rational parameters of temperature of working liquid in the hydraulic drive of the excavator of the fourth dimensional group at different equipment". Bulletin of Kharkov National Automobile and Highway University, n. 95 (16 dicembre 2021): 98. http://dx.doi.org/10.30977/bul.2219-5548.2021.95.0.98.
Testo completoAbstract (sommario):
The article considers the hydraulic drive of a modern excavator on which the influence of the working fluid temperature on the power is established, depending on the technical condition of the hydraulic elements. Studies have shown that new pumps and which have operating wear, have different rational temperature of the working fluid. It is impossible to imagine modern construction machines without equipping them with a hydraulic drive. The operation of the hydraulic drive largely determines the efficiency of operation of both a single machine and the entire fleet, which consists of new and old machines . The efficiency of hydrated machines is ensured in their design, manufacture, and operation, where an important role is played by the parameters of the working fluid: the degree of its contamination and temperature (viscosity). The influence of the temperature of the working fluid on the efficiency of the hydraulic drive and the ability to control the efficiency of the hydraulic drive with the help of temperature have not been studied enough. One of the promising areas in determining the rational temperature of the working fluid is the development of new designs of heat exchangers, heaters, diagnostic devices, which will be able to assess the technical condition of individual elements and the hydraulic drive as a whole. Establishing a rational temperature of the working fluid as a necessary parameter of the hydraulic system is mandatory when using modern methods to increase the efficiency of operation, maintenance and repair of hydraulic drives. With increasing temperature of the working fluid, its viscosity decreases and the loss of pressure and power in the mains of the hydraulic drive. However, this increases the internal flow of hydraulic units, which leads to an increase in power loss. Studies have shown that new pumps and which have operational wear, have different rational temperature of the working fluid. At rational values of temperature to the hydraulic motor the worn out pumps can give almost twice more power, than at 50 ° C, recommended for new pumps. The driving power of the pump, thus, practically does not change.
40
Barbour, S. L., e N. Yang. "A review of the influence of clay–brine interactions on the geotechnical properties of Ca-montmorillonitic clayey soils from western Canada". Canadian Geotechnical Journal 30, n. 6 (1 dicembre 1993): 920–34. http://dx.doi.org/10.1139/t93-090.
Testo completoAbstract (sommario):
Natural Ca-montmorillonite clay soils or engineered clay barriers in western Canada are often used to contain brine generated from the surface disposal of potash tailings or from drilling activities associated with the oil and gas industry. The performance of these barriers has ranged from excellent to poor. The influence of salt brines on the geotechnical properties of these soils has been recognized as a potentially important factor for some time. It has been well documented in the literature that the behavior of clayey soils is strongly influenced by physicochemical interactions between clay particles and pore-fluid chemistry; consequently, the properties of these soils are sensitive to changes in the electrolyte concentration of the pore fluid. An increase in the concentration of the pore fluid to the levels of a concentrated brine can cause significant changes in the geotechnical properties of the soil. In this paper, the impact of brine contamination on the geotechnical properties of two Ca-montmorillonitic clayey soils of glacial origin from western Canada is reviewed. The influence of clay–brine interactions on the index properties (liquid limit, plastic limit, plastic index, mineralogy, density, grain size, and compaction characteristics), mechanical properties (volume change and shear strength), and hydraulic properties (hydraulic conductivity) is described. A quantitative explanation for the changes that occur in the hydraulic and mechanical properties of these soils as a result of brine permeation is also provided. This explanation relates the changes in pore-fluid chemistry to changes in an effective physicochemical stress state. This approach may be used to predict the changes in hydraulic conductivity, volume, or shear strength of a clayey soil as a result of brine contamination. Key words : clay–brine interactions, diffuse double layer, hydraulic conductivity, soil structure, physicochemical.
41
Hay, Nicola. "Because looks aren't everything. A meter for contamination testing of hydraulic fluid". Electronics Education 1994, n. 2 (1994): 25–27. http://dx.doi.org/10.1049/ee.1994.0051.
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Park, Gun, Hyungchul Yoon e Ki-Nam Hong. "Proposed Equations for Calculating Dynamic Hydraulic Pressure in a Rectangular Structure". Applied Sciences 10, n. 23 (26 novembre 2020): 8406. http://dx.doi.org/10.3390/app10238406.
Testo completoAbstract (sommario):
When damaged by an earthquake, a general structure suffers only primary damage such as in the structure’s collapse, whereas a fluid storage structure can cause secondary damage such as environmental contamination or personal injury due to leakage of its internal fluid. In this study, the flow characteristics of fluid inside a fluid storage structure during an earthquake were analyzed, and an equation to calculate the dynamic hydraulic pressure of the fluid acting on the structure during an earthquake was proposed. The seismic load applied to the fluid storage structure was modified to satisfy the design response spectrum in 300 frequencies so that sufficient earthquake energy was obtained in any natural frequency of the fluid storage structure. In addition, the flow characteristics of the fluid inside the fluid storage structure were examined according to the shape change of the seismic wave and the ratio of the height of the fluid to the width of the fluid storage structure. A resulting equation for calculating the hydraulic pressure reflecting the fluctuation characteristics of the fluid was derived, and structural analysis was performed based on this equation and equations proposed by prior research to compare the member force and the hydraulic pressure in a dangerous section. As a result, it was confirmed that the equation proposed in this study showed similar values to previously proposed equations and could obtain fairly reliable results. Therefore, based on the proposed equation in this study, it is possible to calculate hydraulic pressure by reflecting the free-water surface fluctuation characteristics of fluid inside a fluid storage structure during an earthquake.
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He, Zhenghui, Mingqi Cheng e Xiaoping Ji. "AN ANALYSIS OF THE PARTICULATE CONTAMINATION IN HYDRAULIC FLUID USING PATTERN RECOGNITION TECHNIQUES". Proceedings of the JFPS International Symposium on Fluid Power 1989, n. 1 (1989): 595–99. http://dx.doi.org/10.5739/isfp.1989.595.
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Shanbhag, Vignesh V., Thomas J. J. Meyer, Leo W. Caspers e Rune Schlanbusch. "Defining acoustic emission-based condition monitoring indicators for monitoring piston rod seal and bearing wear in hydraulic cylinders". International Journal of Advanced Manufacturing Technology 115, n. 9-10 (28 maggio 2021): 2729–46. http://dx.doi.org/10.1007/s00170-021-07340-8.
Testo completoAbstract (sommario):
AbstractFluid leakage from hydraulic cylinders is a major concern for the offshore industries as it directly affects hydraulic cylinder energy efficiency and causes environmental contamination. There have been attempts made in literature to develop robust condition monitoring techniques for hydraulic cylinders. However, most of these studies were performed to identify degradation of single components. Therefore, in this study, the aim is to monitor degradation of multiple components simultaneously in hydraulic cylinders using acoustic emissions. Experiments performed consist of three test phases and were performed using a hydraulic test rig. In the first test phase, the study is performed to identify acoustic emission features that can be used to monitor piston rod seal wear. In the second test phase, acoustic emission features are identified that can be used to understand bearing wear when unworn, semi-worn or worn piston rod seals are used in hydraulic test rig. In the third test phase, a run-to-failure test is conducted to identify acoustic emission features that can indicate fluid leakage initiation due to piston rod seal wear. The median frequency feature showed good repeatability in all the three test phases to identify piston rod seal wear, bearing wear and fluid leakage initiation during the initial stages in the hydraulic test rig. The proposed acoustic emission-based condition monitoring technique is robust and can be used for the hydraulic cylinders in the industries, as it identifies acoustic emission features based on particular frequency bands associated to specific components, making it less susceptible to noise from other components.
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Fang, Sheng, e Xian Lin Gen. "Managing Varnish of Turbine Oil". Advanced Materials Research 842 (novembre 2013): 341–44. http://dx.doi.org/10.4028/www.scientific.net/amr.842.341.
Testo completoAbstract (sommario):
Varnish now becomes the severe problem of gas turbine, nuclear power plant and other industry which use lubricant oil and hydraulic fluid. The cause of varnish formation is heat, oxidation and contamination. Varnish can cause many turbine problems. The Membrane Patch Colorimetry (MPC) test can be used to measure varnish. Partial or all oil change, Filtration with Cellulose Media and System Chemical Cleaning can be applied to mitigate varnish.
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Otto, Christopher, Svenja Steding, Morgan Tranter, Torsten Gorka, Mária Hámor-Vidó, Wioleta Basa, Krzysztof Kapusta, István Kalmár e Thomas Kempka. "Numerical Analysis of Potential Contaminant Migration from Abandoned In Situ Coal Conversion Reactors". Advances in Geosciences 58 (21 novembre 2022): 55–66. http://dx.doi.org/10.5194/adgeo-58-55-2022.
Testo completoAbstract (sommario):
Abstract. In the context of a potential utilisation of coal resources located in the Mecsek mountain area in Southern Hungary, an assessment of groundwater pollution resulting from a potential water-borne contaminant pool remaining in in situ coal conversion reactors after site abandonment has been undertaken in the scope of the present study. The respective contaminants may be of organic and inorganic nature. A sensitivity analysis was carried out by means of numerical simulations of fluid flow as well as contaminant and heat transport including retardation to assess spatial contaminant migration. Hereby, the main uncertainties, e.g., changes in hydraulic gradient and hydraulic contributions of the complex regional and local fault systems in the study area, were assessed in a deterministic way to identify the relevant parameters. Overall 512 simulations of potential groundwater contamination scenarios within a time horizon exceeding the local post-operational monitoring period were performed, based on maximum contaminant concentrations, cumulative mass balances as well as migration distances of the contaminant plume. The simulation results show that regional faults represent the main contaminant migration pathway, and that contamination is unlikely assuming the given reference model parametrisation. However, contamination within a simulation time of 50 years is possible for specific geological conditions, e.g., if the hydraulic conductivity of the regional faults exceeds a maximum value of 1 × 10−5 m s−1. Further, the parameter data analysis shows that freshwater aquifer contamination is highly non-linear and has a bimodal distribution. The bivariate correlation coefficient heatmap shows slightly positive correlations for the pressure difference, the fault permeability and the simulation time, as well as a negative correlation for the retardation coefficient. The results of this sensitivity analysis have been integrated into a specific toolkit for risk assessment for that purpose.
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Quigley, R. M., F. Fernandez, E. Yanful, T. Helgason, A. Margaritis e J. L. Whitby. "Hydraulic conductivity of contaminated natural clay directly below a domestic landfill". Canadian Geotechnical Journal 24, n. 3 (1 agosto 1987): 377–83. http://dx.doi.org/10.1139/t87-048.
Testo completoAbstract (sommario):
The hydraulic conductivity of natural clays in the 1.5 m contamination zone below a 15 year old domestic waste landfill has been determined.Water-soluble contaminants such as chloride, sodium, and dissolved organic carbon have migrated about 1.0 m compared with only 15 cm for copper, zinc, iron, lead, and manganese. The migration, primarily by diffusion, has rendered the clay perfect for assessment of clay–leachate compatibility with respect to hydraulic conductivity, k.Oedometer tests on tube samples of the clay yielded k values of 1.4 × 10−8 cm/s with a slight decrease to about 1 × 10−8 cm/s in the upper 20 cm of clay at the waste–clay interface. Direct measurement of k on "undisturbed" tube samples, reconsolidated to their field stress state and permeated with pore fluid squeezed from adjacent contaminated samples, yielded values of 1.5 × 10−8 cm/s at 1 m depth decreasing to 0.75 × 10−8 cm/s at the interface.The decrease in k near the interface seems to correlate directly with increased pollutant concentration of soluble species, total heavy metal concentration, and a slight decrease in void ratio. The changes in k are so small, however, that for the test leachates and undisturbed test soils at this domestic waste site, it is concluded that the hydraulic conductivity has not changed significantly as a result of contamination. Key words: domestic waste, leachate, hydraulic conductivity, clay barriers, compatibility.
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Yılmaz, Özgür, Murat Aksoy e Zehan Kesilmiş. "Investigation of the Relationship between Vibration Signals Due to Oil Impurity and Cavitation Bubbles in Hydraulic Pumps". Electronics 11, n. 10 (12 maggio 2022): 1549. http://dx.doi.org/10.3390/electronics11101549.
Testo completoAbstract (sommario):
Although hydraulic pumps are frequently used in daily life, improper use due to oil analysis or oil contamination is ignored. There is no instantaneous inspection; instead, the oil is changed periodically at certain times, whether it is contaminated or not. Hydraulic systems operate based on Pascal’s law, which states that the fluid will distribute the pressure equally to every point in a closed area. The fluid oil taken from an oil reservoir is moved into the pump by engine power. During this movement, as it passes through different pressure areas and different sections, undesirable events such as viscosity change and gas formation occur in the hydraulic oil. These formations collide with the outer walls and cause cavitation with respect to unwanted oil impurities. This cavitation causes unwanted vibration signals to occur in the normal working order of the system. As a result of cavitation, the particles that affect the lubricity and fluidity of the oil in the oil are mixed into the liquid and circulate freely. At the connection points, the blockage caused by the liquid in the pump cylinder block or the valve plate and the collisions of particles is effective. As a result, it creates vibrations of different frequencies. The frequency and amplitudes of these vibrations differ according to the degree of oil contamination. A method has been developed to find the degree of contamination of the oil circulating in the pump by looking at the amplitude and frequency of these vibrations measured from the motor body. There exist standards about the pollution of hydraulic fluid. With these standards, the maximum number of particles allowed for a given pollution level is defined. This topic is discussed in the conclusion to this study. This method has also been proven experimentally. Error and vibration analysis studies on pumps using a different approach are available in the literature. In these studies, pressure variation, total energy transmission, or artificial intelligence models were used to detect anomalies in the pump. In this study, the impurity rate of the oil was set at five different levels and the operating regime of the pump at each level was investigated experimentally. Rayleigh–Plesset and Zwart–Gerber–Belamri models, which are the most common cavitation models, were used to explain the bubble formation in the moving oil and the relationship of these bubbles with vibration. Frequency components were examined by the Discrete Fast Fourier Analysis method, where the operation of the pump was affected by the increase in oil impurity.
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Yuan, Chenggang, Vinrea Lim Mao Lung, Andrew Plummer e Min Pan. "Theoretical and Experimental Studies of a Digital Flow Booster Operating at High Pressures and Flow Rates". Processes 8, n. 2 (10 febbraio 2020): 211. http://dx.doi.org/10.3390/pr8020211.
Testo completoAbstract (sommario):
The switched inertance hydraulic converter (SIHC) is a new technology providing an alternative to conventional proportional or servo-valve-controlled systems in the area of fluid power. SIHCs can adjust or control flow and pressure by means of using digital control signals that do not rely on throttling the flow and dissipation of power, and provide hydraulic systems with high-energy efficiency, flexible control, and insensitivity to contamination. In this article, the analytical models of an SIHC in a three-port flow-booster configuration were used and validated at high operating pressure, with the low- and high-pressure supplies of 30 and 90 bar and a high delivery flow rate of 21 L/min. The system dynamics, flow responses, and power consumption were investigated and theoretically and experimentally validated. Results were compared to previous results achieved using low operating pressures, where low- and high-pressure supplies were 20 and 30 bar, and the delivery flow rate was 7 L/min. We concluded that the analytical models could effectively predict SIHC performance, and higher operating pressures and flow rates could result in system uncertainties that need to be understood well. As high operating pressure or flow rate is a common requirement in hydraulic systems, this constitutes an important contribution to the development of newly switched inertance hydraulic converters and the improvement of fluid-power energy efficiency.
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Taherdangkoo, Reza, Alexandru Tatomir, Mohammad Taherdangkoo, Pengxiang Qiu e Martin Sauter. "Nonlinear Autoregressive Neural Networks to Predict Hydraulic Fracturing Fluid Leakage into Shallow Groundwater". Water 12, n. 3 (17 marzo 2020): 841. http://dx.doi.org/10.3390/w12030841.
Testo completoAbstract (sommario):
Hydraulic fracturing of horizontal wells is an essential technology for the exploitation of unconventional resources, but led to environmental concerns. Fracturing fluid upward migration from deep gas reservoirs along abandoned wells may pose contamination threats to shallow groundwater. This study describes the novel application of a nonlinear autoregressive (NAR) neural network to estimate fracturing fluid flow rate to shallow aquifers in the presence of an abandoned well. The NAR network is trained using the Levenberg–Marquardt (LM) and Bayesian Regularization (BR) algorithms and the results were compared to identify the optimal network architecture. For NAR-LM model, the coefficient of determination (R2) between measured and predicted values is 0.923 and the mean squared error (MSE) is 4.2 × 10−4, and the values of R2 = 0.944 and MSE = 2.4 × 10−4 were obtained for the NAR-BR model. The results indicate the robustness and compatibility of NAR-LM and NAR-BR models in predicting fracturing fluid flow rate to shallow aquifers. This study shows that NAR neural networks can be useful and hold considerable potential for assessing the groundwater impacts of unconventional gas development.