scholarly journals Address for correspondence: Lugovaja Inna S. – Belarusian National Technical University, 12 Ya. Kolasa str., 220013, Minsk, Republic of Belarus. Tel: +375 17 292-84-37 [email protected]

2019 ◽  
Vol 18 (5) ◽  
pp. 422-426
Author(s):  
I. S. Lugovaja
Keyword(s):  
Construction Materials ◽  
High Viscosity ◽  
Petroleum Products ◽  
Working Fluid ◽  
Hydraulic Systems ◽  
Viscous Liquids ◽  
Mineral Oils ◽  
Low Viscosity ◽  
Working Bodies ◽  
Minced Meat

Hydraulic systems used in mechanisms and machines are intended for mechanical movements: load lifting, material pressing, moving of working bodies, etc. Mineral oils with low viscosity are used in them as working fluids. Such liquids include food products (honey, molasses, tar, minced meat, dough, pasta, creams, starches), construction materials (clay, cement, sealant), petroleum products, etc. which are found in chemical and textile, wine and bakery, cosmetic and confectionery, dairy and paintwork, construction industry and many other areas of activity. At the same time, hydraulic systems are used in various sectors of the national economy, which are designed for pumping or transporting a high-viscosity working fluid. However, description of such hydraulic systems, their classification, specific features of the devices of which they consist, has yet received insufficient attention. In this regard, this paper provides a classification of hydraulic systems for pumping and transporting highly viscous liquids, a description of their composition, main types of pumps and devices for controlling and performing technological tasks widely used in various industries. It is shown that all pumps used for these purposes can be divided into two groups: dynamic and volumetric. The paper presents schemes of devices, a brief description and operational principle of pumps used for these purposes. The executed analysis has shown that an operation of hydraulic systems for pumping highly viscous liquids necessitates further study of their characteristics, as well as development of methods for calculation and design.

Micro Surface Shaping for the High-Pressure Operation of Piston Machines With Water as a Working Fluid

2015 ◽  
Author(s):  
Meike H. Ernst ◽  
Monika Ivantysynova
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Working Fluid ◽  
Hydraulic Systems ◽  
Machinery Construction ◽  
Pressure Buildup ◽  
Piston Cylinder ◽  
Low Viscosity ◽  
Load Carrying ◽  
Surface Shaping

Oil is the main working fluid used in the hydraulics industry today — but water is nonflammable, environmentally friendly and cheap: it is the better choice of working fluid for hydraulic systems. However, there is one caveat. Water’s extremely low viscosity undermines its ability to carry load. In forest machinery, construction machinery, and aircraft systems, today’s hydraulic circuits have high operating pressures, with typical values between 300 and 420 bar. These high pressures create the need for high load-carrying abilities in the fluid films of the tribological interfaces of pumps and motors. The most challenging of these interfaces is the piston-cylinder interface of swashplate type piston machines, because the fluid must balance the entire piston side load created in this design. The low viscosity of the water turns preventing metal-to-metal contact into quite a challenge. Fortunately, an understanding of how pressure builds and shifts about in these piston-cylinder lubrication interfaces, coupled with some clever micro surface shaping, can allow engineers to drastically increase the load-carrying ability of water. As part of this research, numerous different micro surface shaping design ideas have been simulated using a highly advanced non-isothermal multi-physics model developed at the Maha Fluid Power Research Center. The model calculates leakage, power losses, film thickness and pressure buildup in the piston-cylinder interface over the course of one shaft revolution. The results allow for the comparison of different surface shapes, such as axial sine waves along the piston, or a barrel-shaped piston profile. This paper elucidates the effect of those surface profiles on pressure buildup, leakage, and torque loss in the piston-cylinder interface of an axial piston pump running at high pressure with water as the lubricant.

scholarly journals Alternative rapeseed based oil fluid for hydraulic systems of tractors

2021 ◽  
Vol 37 ◽  
pp. 00030
Author(s):  
Alexander P. Bychenin ◽  
Oleg S. Volodko ◽  
Denis N. Bazhutov
Keyword(s):  
Vegetable Oils ◽  
Tribological Properties ◽  
Rapeseed Oil ◽  
Alternative Fuels ◽  
Working Fluid ◽  
Hydraulic Systems ◽  
Agricultural Machinery ◽  
Laboratory Findings ◽  
Hydraulic Oil ◽  
Mineral Oils

The paper analyzes the main applications of alternative fuels and lubricants in automotive vehicles, considers the possibility of using vegetable oils as a working fluid for hydraulic systems of agricultural machinery. Based on the laboratory findings, it states the ways to improve a lubrication formula based on rapeseed oil. The formula is proven to be optimal if it includes 88.9% rapeseed oil + 3.7% D-11 + 3.2% EFO + 4.197% graphite + 0.003% MS-200A, which is superior in tribological properties to MGE-46V hydraulic oil, and can be recommended for use in hydraulic systems of agricultural machinery as an alternative to mineral oils.

The Influence of Lubricant Viscosoty in Cold Work Forward Extrusion Using Micro–Pits Tool

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
A. Norhayati ◽  
S. Maizan ◽  
H.M. Zin ◽  
J. Y. Wira ◽  
W. B. Wan Nik ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Plane Strain ◽  
Cold Work ◽  
High Viscosity ◽  
Experimental Results ◽  
Grid Pattern ◽  
Mineral Oils ◽  
Low Viscosity ◽  
Billet Surface ◽  
Taper Die

The present research concerns on the study of the effects of micro–pits arrays formed on taper die using cold forward plane strain extrusion experiments. Each pit was of reverse pyramids configuration having 330 microns diagonal length. The pits were 860 microns apart each others. Two additive free paraffinic mineral oils with low viscosity (P2) and high viscosity (P3) were used in this experimental work. The experimental results were compared with the results obtained from the plane strain extrusion experimental works with taper die without micro–pits (NA). The experimental results focused on the extrusion load, billet surface roughness and billet grid pattern on inclination slope. From the results, the existence of the micro–pits array on the taper die surface affected the extrusion load. At the same time, the micro–pits array affected the extruded billet surface roughness after the experiments. From this experiment, we could conclude that the micro–pits formed on the taper die (PA) would control the frictional constraint on the taper die compared to those without the micro–pits (NA). However, high viscosity lubricant (P3) was found to cause more effects compared to low viscosity lubricant (P2).

Single-Phase Model for Electric Submersible Pump (ESP) Head Performance

SPE Journal ◽  
2006 ◽  
Vol 11 (01) ◽  
pp. 80-88 ◽  
Author(s):  
Datong Sun ◽  
Mauricio G. Prado
Keyword(s):  
Single Phase ◽  
High Viscosity ◽  
Phase Model ◽  
Theoretical Research ◽  
Working Fluid ◽  
Two Phase ◽  
Cross Sectional ◽  
Pump Performance ◽  
Low Viscosity ◽  
Artificial Lift

Summary This paper presents a new incompressible single-phase model for ESP head performance. Sachdeva (1988, 1994) and Cooper and Bosch (1966) developed models for ESP channels and for inducers, respectively. The model presented in this paper is based on 1D approximation along an ESP channel. The new derived pressure ordinary differential equation (ODE) for frictionless incompressible flow (Bird 1960) is consistent with the pump Euler equation. New models for pump frictional and shock losses have been proposed. Finally, a comparison between the predicted pump performance and the pump performances derived from the affinity law for different rotational speeds is presented. The single-phase model can predict ESP performance under different fluid viscosities and also is the basis of a gas/liquid model for ESP head performance. Introduction ESPs are dynamic multistage devices that use kinetic energy to increase liquid pressure. The relationship between the head developed by the pump and the flow rate through the pump for a certain rotational speed is usually known as the pumphead performance curve. This curve is experimentally determined by the pump manufacturer using water as the working fluid. As a consequence, published pumphead performance curves can be used for any other low-viscosity, single-phase liquid, independent of its density. Pump performance, however, is significantly affected by the presence of free gas or high-viscosity fluids. The U. of Tulsa Artificial Lift Projects (TUALP) is currently conducting experimental as well as theoretical research to improve the understanding of pump performance when handling viscous fluids and two-phase flow mixtures at different pump rotational speeds. A better understanding of the pump performance under those conditions will certainly contribute to a reduction in the uncertainty of engineering tools for the selection, design, and operation of ESPs in more challenging applications. This paper presents the new single-phase model developed for the prediction of an ESP's performance. The model consists of the mass and momentum equations, based on the streamline approach or 1D assumption. In the momentum equations, the calculation of the friction factor proposed by Sachdeva is improved by incorporating the channel curvature, channel rotation, and channel cross-sectional effects. A new shock loss model, including rotational speeds, has been proposed. The new single-phase model is capable of predicting the pump performance for different pump rotational speeds and for different fluid viscosities.

scholarly journals A Low-Viscosity BisGMA Derivative for Resin Composites: Synthesis, Characterization, and Evaluation of Its Rheological Properties

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 338
Author(s):  
Ali Alrahlah ◽  
Abdel-Basit Al-Odayni ◽  
Haifa Fahad Al-Mutairi ◽  
Bashaer Mousa Almousa ◽  
Faisal S. Alsubaie ◽  
...  
Keyword(s):  
Substantial Reduction ◽  
Triethylene Glycol ◽  
High Viscosity ◽  
Resin Matrix ◽  
Resonance Spectroscopy ◽  
Dental Resin ◽  
Triethylene Glycol Dimethacrylate ◽  
Oh Groups ◽  
Low Viscosity ◽  
13C Nuclear Magnetic Resonance

This study aimed to synthesize new bisphenol A-glycidyl methacrylate (BisGMA) derivatives, targeting a reduction in its viscosity by substituting one of its OH groups, the leading cause of its high viscosity, with a chlorine atom. Hence, this monochloro-BisGMA (mCl-BisGMA) monomer was synthesized by Appel reaction procedure, and its structure was confirmed using Fourier transform infrared spectroscopy, 1H and 13C-nuclear magnetic resonance spectroscopy, and mass spectroscopy. The viscosity of mCl-BisGMA (8.3 Pa·s) was measured under rheometry conditions, and it was found to be more than 65-fold lower than that of BisGMA (566.1 Pa·s) at 25 °C. For the assessment of the viscosity changes of model resins in the presence of mCl-BisGMA, a series of resin matrices, in which, besides BisGMA, 50 wt % was triethylene glycol dimethacrylate, were prepared and evaluated at 20, 25, and 35 °C. Thus, BisGMA was incrementally replaced by 25% mCl-BisGMA to obtain TBC0, TBC25, TBC50, TBC75, and TBC100 blends. The viscosity decreased with temperature, and the mCl-BisGMA content in the resin mixture increased. The substantial reduction in the viscosity value of mCl-BisGMA compared with that of BisGMA may imply its potential use as a dental resin matrix, either alone or in combination with traditional monomers. However, the various properties of mCl-BisGMA-containing matrices should be evaluated.

scholarly journals A Conceptional Approach of Resin-Transfer-Molding to Rosin-Sourced Epoxy Matrix Green Composites

Aerospace ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Sicong Yu ◽  
Xufeng Zhang ◽  
Xiaoling Liu ◽  
Chris Rudd ◽  
Xiaosu Yi
Keyword(s):  
Composite Laminates ◽  
Resin Transfer Molding ◽  
High Viscosity ◽  
Ramie Fiber ◽  
Liquid Composite Molding ◽  
Curing Agent ◽  
Molding Process ◽  
Transfer Molding ◽  
Low Viscosity ◽  
Composite Molding

In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites.

Electrochemical Evaluation for Rust Preventive Properties of Rust Preventive Oils Coated on Fe-Cu-C Sintered Steel

2014 ◽  
Vol 783-786 ◽  
pp. 2537-2540 ◽  
Author(s):  
Satoshi Sunada ◽  
Norio Nunomura ◽  
Sayaka Hirata ◽  
Naoki Nagase
Keyword(s):  
Open Circuit Potential ◽  
High Viscosity ◽  
Open Circuit ◽  
Second Step ◽  
Sintered Steel ◽  
Corrosive Solution ◽  
The Third ◽  
Low Viscosity ◽  
Sintered Steels ◽  
Electrochemical Evaluation

Since Fe-Cu-C sintered steels are easily rusted, they are coated with rust preventive oils. High viscosity of those rust preventive oils decrease workability, and low viscosity deteriorates rust preventive performance. Therefore, it is necessary to develop new rust preventive oils with contradictory properties of low viscosity and superior rust prevention. However, precise methodology to evaluate rust prevention ability has not been established. In this study, we developed new technique to quantitatively evaluate rust prevention ability by measuring the open circuit potential through thin corrosive solution on Fe-Cu-C sintered steels coated with a rust preventive oils. As a result, the ability for rust prevention can be measured quantitatively, and it decreases slowly over time, with repeating destruction and restoration. Furthermore, it was found that the deteriorating processes of rust prevention ability for rust prevention oils are composed of three characteristics steps respectively. That is, in the first step the great open circuit potential changes from 0V to-0.3V with repetition were observed where the excellent rust prevention ability was kept, in the second step it decreases slowly from-0.1V to-0.4V with oscillation of the small potential changes where the gradual decrease of rust prevention ability was recognized and in the third step it decreases monotonously in the lower potential than-0.4V where the rust was observed because of the remarkable deteriorating of the rust prevention ability.

Synthesis and Characterization of Polydimethylsiloxane (PDMS) with Medium Viscosity via Ring-Opening Polymerization

2021 ◽  
Vol 1028 ◽  
pp. 346-351
Author(s):  
Soni Setiadji ◽  
Zulfi Mofa Agasa ◽  
Diba G Auliya ◽  
Fitrilawati ◽  
Norman Syakir ◽  
...  
Keyword(s):  
Ring Opening ◽  
Vitreoretinal Surgery ◽  
High Viscosity ◽  
Ring Opening Polymerization ◽  
Vitreous Humour ◽  
Synthesis And Characterization ◽  
Low Viscosity ◽  
A Value ◽  
Medium Viscosity

Duration of use and injectability are external factors for Polydimethylsiloxane (PDMS) that needs to be considered when PDMS utilized as a vitreous substituted liquid in vitreoretinal surgery. In general, PDMS which has been used as a substitute for vitreous humour is PDMS with a low viscosity in the value about 1000 cSt and a high viscosity at a value of about 5000 cSt. Various deficiencies have been encountered from low and high viscosity of PDMS, causing research to be continued to obtain PDMS which has suitable properties as a substitute for vitreous humour. One of them is research to obtain medium viscosity of PDMS with a viscosity value of about 2000 cSt. Here, we reported synthesis and characterization of PDMS with medium viscosity in ranges from 1800 to 2600 mPas. PDMS was synthesized through Ring-Opening Polymerization (ROP) pathway using the monomer of Octamethylcyclotetrasiloxane (D4) and the chain terminator of Hexamethyldisiloxane (MM). Various concentrations of potassium hydroxide (KOH) of 3, 4, 6 and 8 %(w/v) were applied as initiator to form gel of PDMS. All synthesized PDMS samples were identified to have viscosity values of 1800-2600 mPas, refractive index values of 1.4042-1.4044 and surface tension values of 22-23 mN/m. Meanwhile, the results of Fourier-Transform Infrared (FTIR) measurement showed that the absorption peaks were similar to that of our previous report.

Calculation of a closed hydraulic volumetric system

2021 ◽  
pp. 27-30
Author(s):  
Keyword(s):  
Power Plant ◽  
Wind Power ◽  
Hydraulic System ◽  
Working Fluid ◽  
Wind Power Plant ◽  
Hydraulic Systems ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Oil Pump ◽  
Selection Of

An algorithm is proposed for calculating a closed volumetric hydraulic pump-hydraulic motor system using the example of the hydraulic system of a wind power plant, based on the calculation of the hydraulic systems of mobile machines. The main characteristics of the system components, the selection of initial data for the calculation, working fluid and diameters of hydraulic lines are analyzed. Keywords: hydraulic system, energy, fluid, oil, pump, motor, renewable energy source, wind power plant, machine. [email protected]

Impact of Resin Composite Viscosity and Fill-technique on Internal Gap in Class I Restorations: An OCT Evaluation

2021 ◽  
Author(s):  
KR Kantovitz ◽  
LL Cabral ◽  
NR Carlos ◽  
AZ de Freitas ◽  
DC Peruzzo ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Resin Composite ◽  
Oral Care ◽  
High Viscosity ◽  
Class I ◽  
Low Viscosity ◽  
Significant Difference ◽  
Before And After ◽  
Internal Adaptation ◽  
Internal Gap

SUMMARY The aim of this in vitro study was to quantitatively evaluate the internal gap of resin composites of high-and low-viscosity used in single- and incremental-fill techniques in Class I cavities exposed to thermal cycling (TC) using optical coherence tomography (OCT). Cavities of 4-mm depth and 3-mm diameter were prepared in 36 third molars randomly distributed into four groups, according to viscosity of restorative resin-based composite (high or low viscosity, all from 3M Oral Care) and technique application (bulk or incremental fill) used (n=9): RC, high-viscosity, incremental-fill, resin-based composite (Filtek Z350 XT Universal Restorative); BF, high-viscosity, bulk-fill, resin-based composite (Filtek One Bulk Fill); LRC, low-viscosity, incremental-fill, resin-based composite (Filtek Z350 XT Flowable Universal Restorative); and LBF, low-viscosity, bulk-fill, resin-based composite (Filtek Flowable Restorative). Single Bond Universal Adhesive system (3M Oral Care) was used in all the experimental groups. The incremental-fill technique was used for RC and LRC groups (2-mm increments), and a single-layer technique was used for BF and LBF groups, as recommended by the manufacturer. The internal adaptation of the resin at all dentin walls was evaluated before and after TC (5000 cycles between 5°C and 55°C) using OCT images. Five images of each restored tooth were obtained. Images were analyzed using ImageJ software that measured the entire length of the gaps at the dentin–restoration interface. The length of gaps (μm) was analyzed using two-way repeated measures ANOVA and the Tukey tests (α=0.05). There was a significant interaction between material types and TC (p=0.006), and a significant difference among all material types (p<0.0001), before and after TC (p<0.0001). Increased internal gaps at the dentin–restoration interface were noticed after TC for all groups. RC presented the lowest value of internal gap before and after TC, while LBF showed the highest values of internal gap after TC. In conclusion, TC negatively affected the integrity of internal gap, whereas high-viscosity, incremental-fill, resin-based composite presented better performance in terms of internal adaptation than low-viscosity, bulk-fill materials in Class I cavities.

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