fluid parameters
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BACKGROUND: In modern research standards, a semi-quantitative evaluation scale with crosses is used to characterize turbid cerebrospinal fluid samples, where the absence of turbidity is evaluated as a clear cerebrospinal fluid (a variant of norm), and turbidity is evaluated, depending on the severity, by a different number of crosses. This approach is highly subjective. AIM: Development of a simple objective method for assessment of turbidity of the cerebrospinal fluid. MATERIALS AND METHODS: The optimal wavelength was determined by examination of the optical density of turbid samples of barium sulfate at various wavelengths on Stat Fax photometer (Awarenes, USA). Turbidity was standardized using Shank–Hoagland scale. The reference range was evaluated based on the results of 10 measurements of 10 samples of visually unchanged cerebrospinal fluid. At the same time, the stability and reproducibility of the measured parameters were evaluated. RESULTS: The optimal wavelength diabase is the range emitted by red light filter (λ = 670 nm). Stability of cerebrospinal fluid parameters is preserved for 2 hours after its obtaining. The reference range for normal cerebrospinal fluid samples does not exceed 0.1 units of turbidity on Shank–Hoagland scale. CONCLUSION: The presented methods demonstrate the importance and possibilities of objectivization of characterization of the properties of cerebrospinal fluid with use of the proposed method.

The work considers for the first time the preparation of sorbents based on hypercrosslinked polysterene (HCP) and chelating agent N,N,N′,N′-tetraoctyldiglycolamide (TODGA) by impregnation in the supercritical (SC) CO2 medium. Such sorbents can be applied for further isolation and separation of lanthanides, actinides and other metals. They are usually prepared by impregnation in toxic organic solvents (e.g., methanol, dichloromethane). Our study shows that application of SC CO2 instead of organic solvents can significantly speed up the impregnation, perfom it in one stage and make the process more eco-friendly. At the same time, the obtained sorbents are close in their parameters to the classical ones. This article presents the results of measuring the TODGA adsorption isotherms on two HCP sorbents (MN202 and MN270) on a wide range of SC fluid parameters. Adsorption measurements were carried out using on-line supercritical fluid chromatography and gravimetry. Based on the sorption capacity parameter, MN202 sorbent was selected as the better carrier for TODGA. An impregnation temperature increase within the range 313–343 K in isochoric conditions (ρ = 0.780 g/mL) reduces the maximum of TODGA adsorption from ~0.68 mmol/g to ~0.49 mmol/g.

This paper deals with the dynamics of cylindrical collapse with anisotropic fluid distribution in the framework of [Formula: see text] gravity. For this purpose, we consider non-static and static cylindrical spacetimes in the inner and outer regions of a star, respectively. To match both geometries at the hypersurface, we consider the Darmois junction conditions. We use the Misner–Sharp technique to examine the impacts of correction terms and effective fluid parameters on the dynamics of a cylindrical star. A correlation between the Weyl tensor and physical quantities is also developed. The conformally flat condition is not obtained due to the influence of anisotropic pressure and higher-order nonlinear terms. Further, we assume isotropic fluid and specific model of this theory which yields the conformally flat spacetime and inhomogeneous energy density. We conclude that the collapse rate reduces as compared to general relativity due to the inclusion of effective pressure and additional terms of this theory.

In this investigation, we have analyzed the peristaltic movement of MHD Carreau nanofluids in a curved channel by taking the thermophoresis and Brownian motion effects into account. The governing equations of the fluid flow like the equations of continuity, momentum, temperature and concentration are modulated and abridged by using the theory of lubrication approximations. A regular perturbation is used to solve the simplified coupled nonlinear differential equations. The changes of various fluid parameters on axial velocity, temperature and concentrations are carefully calculated, and the graphical results are analyzed. According to the result of this study, it is determined that the resulting velocity of nanofluid decreases significantly when the applied radial magnetic field is strengthened. In addition, the curvature parameter has a significant impact on the concentration function, and when the curvature of the channel is increased, the absolute value of the nanoparticle concentration distribution diminishes.

Abstract Two main topics are presented in this work which enable more efficient use of oil condition monitoring systems based on resonant fluid sensing. A new fluid model for a recently introduced compact measurement unit for oil condition monitoring based on simultaneous measurement of viscosity and density is discussed. It is shown that a new fluid model allows achieving higher accuracies, which is demonstrated by comparison to earlier models. The second topic deals with measuring fluid parameters over varying temperatures and thus providing additional monitoring parameters and enhanced data consistency. We propose an alternative representation of the Vogel model using transformed parameters having a clear physical meaning and which are more stable in presence of measurement noise.

Abstract The Operator's challenge was the construction of a sub-horizontal well with 1500 m liner section in area with limited offset experience. The main development difficulty of the East Urengoy license area is the abnormally high pore pressure Achimov deposit. The widely used practice of drilling for these reservoirs with S-shaped profile wells has been utilized for a long while. However, the construction of sub-horizontal wells is still a challenge, and often accompanied by high incident rates. Before drilling the well, all necessary fluid engineering modelling was performed. According to the hydraulic calculations, drilling of the horizontal well with traditional fluid properties was not possible due to exceeding the maximum ECD range. Multiple laboratory tests were performed to optimize the drilling fluid parameters and rheological properties with respect to ECD reduction and reducing potential for weight fluctuations due to barite sag. Based on the data obtained, recommendations were issued to predict ECD levels while drilling and tripping. At the same time, step-by-step action plans were developed for trouble-free drilling. While utilizing this optimized fluid, with close interaction and cooperation between the project Operator (ROSPAN International), the Customer's research and development center, technical support service and the drilling contractor, the first sub-horizontal well on this licensed site has been successfully drilled. The following main actions were developed and executed during the well construction process: Maintained the hydraulic pressure (marginally) above the pore pressure through careful fluid management. The rheological properties of the drilling fluid were maintained to the developed (lab verified) specifications. Careful hydraulic pressure management during tripping. Extensive planning of the tripping operations included increasing the mud weight before tripping to create the necessary margin and optimization of the tripping rate. Ensuring effective drilling parameters and preparing the wellbore for the casing run according to hydraulic calculations. Recommended optimized drilling fluid parameters aimed at preventing barite sag under abnormally high pore pressure and high bottom hole temperatures (up to 110 deg C). Use of specialized pills to assist prevent the loss of circulation and wellbore instability. This article is devoted to the development of drilling fluid solutions and practical techniques for effectively drilling wells in the area with challenging formations. This case study, as well as the lessons learned will be used for ongoing drilling projects in the area.

Background. The article provides an overview of existing complexes (units) for continuous monitoring of drilling fluid parameters in automatic mode. Aim. To justify the need to develop a complex (module) that will allow combining existing technologies and making a step forward in the field of process automation in terms of monitoring the parameters of drilling fluids. Materials and methods. In the current realities of well construction, the control of drilling fluid parameters on almost all drilling rigs operating on the territory of Russia (possibly with the exception of a few off shore projects) is carried out by the work of a solution engineer, usually a representative of a service company. The analysis of the parameters, depending on the number of personnel, the speed of penetration, the complexity or importance of the well, can be carried out from 2 to 6 times a day [1, 2]. This means a complete analysis, rather than monitoring the density and conditional viscosity, which can be measured by a representative of the drilling crew, for rapid response, and with greater frequency. Due to such a low measurement discreteness, there is a high probability of a significant deviation of the drilling fluid parameters from the design values. As a result, the probability of various complications, both geological and technological, increase significantly. Results. During the analysis of information from open sources, the most promising complexes (modules) from the point of view of application in the current conditions were identified, their positive and negative sides were evaluated. As a result of the conducted review of open sources, the most promising complexes (modules) in terms of application in the current conditions are identified, the positive and negative sides of the systems under consideration are displayed, and the need to develop a complex (module) that will combine all the best that is available today and make a qualitative step forward in the field of “peopleless” technologies used during drilling wells in terms of monitoring the parameters of drilling fluids is justified. Conclusions. The necessity of developing a complex (module) for automating processes in terms of monitoring the parameters of drilling fluids is justified.

We present a recent development of the MUFITS reservoir simulator aiming at modelling the transport of fluids whose properties and phase equilibria are calculated in a user-supplied external shared library. Both the explicit correlations and tabulated data for the fluid parameters can be implemented in the library that we name the EoS-module (Equation of State-module). An iterative approach—which, for example, is based on the phase equilibria calculation through the Gibbs energy minimisation (GEM) method, can also be used in the EoS-module. A considerable effort has been undertaken to minimise the number of program procedures exported by the shared library. This should facilitate and ease the usage of the developed software extension by the scientific community. Furthermore, we supplement the article with the source code of two simple EoS-modules that can serve as templates in other modelling and software development efforts. The EoS-modules are also useful for coupling MUFITS with other elaborate software for fluid property prediction. To demonstrate such a possibility, we supplement the article with the source code of a more complicated EoS-module that couples MUFITS with the geochemical code GEMS3K. This module is used in a simple 1-D benchmark study showing the capabilities of MUFITS for modelling reactive transport in porous media.