Critical Study of a Residual Viscosity Correlation of JOSSI: Pure Hydrocarbons Case

2020 ◽  
Vol 986 ◽  
pp. 61-67
Author(s):  
Mohamed Jaouad Malzi ◽  
Aziz Ettahir ◽  
Christian Boned ◽  
Bernard Lagourette ◽  
Kamal Kettani ◽  
...  
Keyword(s):  
Equations Of State ◽  
Critical Study ◽  
Average Deviation ◽  
Cubic Equation ◽  
Viscosity Correlation ◽  
Opposite Situation ◽  
Pure Substances ◽  
Reduced Density

The most common residual viscosity correlation used in the petroleum models is JOSSI et al [1] where the residual viscosity is represented by a polynomial function of 4th degree involving the reduced density ρr ([(η-η*)ξ+10-4]1/4=Σ41=0(aiρri)). Based on this formula, it is possible to predict various uncertainties that can be accumulated and thus alter the performance of viscosity restitution which depends on several factors:The quality of the initial adjustment of the coefficients ai;The precision on the density;The accuracy with which are known the characteristics of the constituents of bases;The validity of the rule of the mixtures selected for the determination of the pseudo-critical coordinates Tcm and Pcm and the equivalent molar mass of the mixture.As far as the results are concerned, we reveal that with the new set of coefficients it is possible to obtain a more preciserepresentation compared to that of JOSSI. The method of JOSSI seems to be especially interesting for the viscosities restitution of systems containing light and close paraffins. However, for some pure substances, the opposite situation could be true. Among the four equations-of-state used, it has been found that the cubic equation-of-stateof PENG and ROBINSON should not be used since we would like to generate the density. Finally, we are not expecting a perfect systematic representation. As demonstrated in our model, if for light alkanes one can expect an average deviation ofless than 10%, for certain pure substances the deviation exceeds 20%.

scholarly journals Performance of the Self-Referencing Model on the Determination of Viscosity versus Pressure and Temperature of Various Hydrocarbons and Their Mixtures

2019 ◽  
Vol 9 (2) ◽  
pp. 3289-3297
Keyword(s):  
Calibration Procedure ◽  
The Self ◽  
Reference Temperature ◽  
Light Hydrocarbons ◽  
Average Deviation ◽  
Gaseous State ◽  
Pure Substances ◽  
Experimental Values

The predictive model of the viscosimetric behavior studied in this article is the self-referencing model developed in our laboratory by KANTI et al. The dominant idea of this method is to characterize the dynamic viscosity (P,T) of a fluid just knowing its viscosity at P0=0.1MPa and at a reference temperature T0 (generally ambient temperature). For this purpose, we used the database developed by us (more than 15000 experimental couples P, T of 56 references) from which we extracted 4304 viscosity values (P,T) corresponding to 1866 experimental values of pure substances and 2213 of mixtures with 216 values of petroleum cuts Our study shows that the absolute average deviation respectively for pressures ≤ 1000 bars and ≤ 5055 bars (7.3% and 10.5%) obtained for pure substances (≥6 carbons) and (6.8 and 7.5%) for mixtures is satisfactory. Moreover when coupled with mixing rules (GRUMBERG-NISSAN and KENDALL-MONROE equations) without adjustable parameters it was able to account satisfactory for the variation of the viscosity (P,T,x) of the mixtures on the simple knowledge of the viscosity of the components of the mixture considered, at reference temperature T0 and at 0.1MPa. For all the mixtures studies an absolute average deviation respectively for pressures ≤1000 bar and ≤5055 bars of 8.6% and 9.8 without binary C1+C10 and 12.5% and 13% with binary C1+C10 was observed. It should also be noted that the self-referencing method seems to be particularly interesting for the restitution of the viscosities of systems containing heavy hydrocarbons in the liquid state and finds its limits for substances on gaseous state or light hydrocarbons (<6 carbons). The method depends also on the quality of the adjustment of the coefficients. If we consider that the coefficients were initially adjusted to moderately heavy substances, it might be interesting to resume the calibration procedure by including lighter substances

scholarly journals A MultiScale Gibbs-Helmholtz Constrained Cubic Equation of State

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Angelo Lucia
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
Internal Energy ◽  
Equations Of State ◽  
Energy Parameter ◽  
New Approach ◽  
Cubic Equation Of State ◽  
Cubic Equation ◽  
Dynamics Simulations

This paper presents a radically new approach to cubic equations of state (EOS) in which the Gibbs-Helmholtz equation is used to constrain the attraction or energy parameter, a. The resulting expressions for for pure components and for mixtures contain internal energy departure functions and completely avoid the need to use empirical expressions like the Soave alpha function. Our approach also provides a novel and thermodynamically rigorous mixing rule for . When the internal energy departure function is computed using Monte Carlo or molecular dynamics simulations as a function of current bulk phase conditions, the resulting EOS is a multiscale equation of state. The proposed new Gibbs-Helmholtz constrained (GHC) cubic equation of state is used to predict liquid densities at high pressure and validated using experimental data from literature. Numerical results clearly show that the GHC EOS provides fast and accurate computation of liquid densities at high pressure, which are needed in the determination of gas hydrate equilibria.

scholarly journals A New Method to Calculate the Pure Component Parameters of Any Two-Parameter Equation of State

2011 ◽  
Vol 2011 ◽  
pp. 1-6
Author(s):  
Isam H. Aljundi
Keyword(s):  
Equation Of State ◽  
Equations Of State ◽  
Saturated Vapor ◽  
Pure Component ◽  
New Method ◽  
Average Deviation ◽  
Cubic Equation ◽  
Parameter Equation ◽  
Temperature Dependences ◽  
Two Parameter

Reliable equations of state are very important in the design of refrigeration cycles, since thermodynamic properties can be calculated by simple differentiation. In this paper, a new method to calculate the parameters of any two-parameter equation of state is presented. The method is based on the use of Clapeyron equation and the experimental PVT data. This method was tested on a newly developed cubic equation of state and proved to be simple and fast. Results showed orders of magnitude enhancement in prediction of the saturated vapor pressure even near the critical region. The Percent Absolute Average Deviation (%AAD) was always less than 0.1 in the studied cases. It also showed that the parameters calculated using the original equation deviate strongly from the “experimental” values as the temperature decreases below the critical point. This method can be used to redefine the temperature dependences of these parameters and develop new mixing rules for the mixtures.

Role of the National Institute of Standards and Technology (NIST) in Support of the Vitamin D Initiative of the National Institutes of Health, Office of Dietary Supplements

2017 ◽  
Vol 100 (5) ◽  
pp. 1260-1276 ◽  
Author(s):  
Stephen A Wise ◽  
Susan S-C Tai ◽  
Carolyn Q Burdette ◽  
Johanna E Camara ◽  
Mary Bedner ◽  
...  
Keyword(s):  
Vitamin D ◽  
Dietary Supplements ◽  
National Institutes Of Health ◽  
Critical Study ◽  
Dihydroxyvitamin D3 ◽  
Assurance Scheme ◽  
Quality Assurance Scheme

Abstract Since 2005, the National Institute of Standards and Technology (NIST) has collaborated with the National Institutes of Health (NIH), Office of Dietary Supplements (ODS) to improve the quality of measurements related to human nutritional markers of vitamin Dstatus. In support of the NIH-ODS Vitamin D Initiative, including the Vitamin D Standardization Program (VDSP), NIST efforts have focused on (1) development of validated analytical methods, including reference measurement procedures (RMPs); (2) development of Standard ReferenceMaterials (SRMs); (3) value assignment of critical study samples using NIST RMPs; and (4) development and coordination of laboratory measurement QA programs. As a result of this collaboration, NIST has developed RMPs for 25-hydroxyvitamin D2 [25(OH)D2], 25(OH)D3, and 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3]; disseminated serum-based SRMs with values assigned for 25(OH)D2, 25(OH)D3, 3-epi-25(OH)D3, and 24R,25(OH)2D3; assigned values for critical samples for VDSP studies, including an extensive interlaboratory comparison and reference material commutability study; provided an accuracy basis for the Vitamin D External Quality Assurance Scheme; coordinated the first accuracy-based measurement QA program for the determination of 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3 in human serum/plasma; anddeveloped methods and SRMs for the determination of vitamin D and 25(OH)D in food and supplement matrix SRMs. The details of these activities and their benefit and impact to the NIH-ODS Vitamin D Initiative are described.

Tingkat Pemahaman Kompetensi Guru Pada Mahasiswa Pendidikan Geografi Sebagai Calon Guru Geografi

2020 ◽  
Vol 21 (1) ◽  
pp. 102-117
Author(s):  
Novia Zalmita ◽  
Muhajirah Muhajirah ◽  
Abdul Wahab Abdi
Keyword(s):  
Prospective Teachers ◽  
Prospective Teacher ◽  
Quantitative Description ◽  
Population Data ◽  
Geography Education ◽  
Teacher Competence ◽  
Education Department ◽  
Long Time

One that influences human resource indicators is education. The teacher is a profession as a job of academic specialization in a relatively long time in college. Understanding related to teacher competence is very important to have by a prospective teacher because it can affect the quality of performance as a professional teacher. The teacher's competence is known as pedagogic, professional, social and personality competencies. The issue in this study is how the competency of the teacher of the Department of Geography Education FKIP Unsyiah as a prospective teacher of geography? The purpose of this study was to determine the competence of teachers in the Department of Geography Education FKIP Unsyiah as prospective geography teachers. Quantitative description approach is used in this study to find answers to the issue. The population in this study were students of the Department of Geography Education FKIP Unsyiah class of 2015 and 2016 who had been declared to have passed the Micro Teaching and Magang Kependidikan 3 course totaling 50 people. Because the population is small and can be reached, the determination of the sample using total sampling techniques so that the sample in this study is the whole population. Data collection is done by distributing test questions to respondents. The data was analyzed using the descriptive statistics percentage formula. The results of the study indicate that the level of teacher competence of Geography Education Department students as prospective teachers is in the moderate category, namely as many as 22 respondents (44%). A total of 12 respondents (24%) were in the high category, 15 respondents (30%) were in the low category and 1 respondent (2%) were in the very low category.

Fluctuations of Annual Precipitation and Water Resources Quality in Ukraine

2016 ◽  
Vol 10 (4s) ◽  
pp. 621-629
Author(s):  
Valentina Pidlisnyuk ◽  
◽  
John Harrington JR ◽  
Yulia Melnyk ◽  
Yuliya Vystavna ◽  
...  
Keyword(s):  
Water Resources ◽  
Surface Waters ◽  
Precipitation Amount ◽  
Ion Concentration ◽  
Annual Precipitation ◽  
Resource Quality ◽  
Phosphate Ion ◽  
Regional Trends

The article focuses on examining the influence of fluctuations in annual precipitation amount on the quality of surface waters. Water quality was estimated with data on BOD, COD and phosphate–ion concentration within five selected regions of Ukraine. Analysis of the precipitation data (1991 – 2010) showed different regional trends. Using the statistics, determination of the interconnection between precipitation amount and water resources quality were done. The obtained regularities and associated uncertainties can be used for prediction of changes in water resource quality and as a guide for future adaptation to possible climate change.

POTENSI PENGEMBANGAN SADE SEBAGAI DESA WISATA LOMBOK

2016 ◽  
Vol 20 (2) ◽  
pp. 69-82
Author(s):  
W. Suprihatin ◽  
H. Hailuddin
Keyword(s):  
Analytical Hierarchy Process ◽  
Environmental Aspect ◽  
Priority Level ◽  
Highest Weight ◽  
Local Tradition ◽  
Tourist Village ◽  
Hierarchy Process ◽  
Initial Pattern

The background of the problems in this study is the decreasing quality of Sade hamlet amid rising tourist arrivals. From the environmental aspect, the conditions of the hamlet began to decline, in which the initial pattern of Sade has started a lot of changes towards the deficient and began to leave the local tradition. One effort to improve the condition of Sade hamlet in social, cultural and the environmental aspect is through the formulation of a sustainable structuring, the presence and identity maintaining and making a sustainable Tourism Village. Through analysis of AHP (Analytical Hierarchy Process) by collecting the perceptions of some experts through interviews and questionnaires, obtained by weighting the priority of the experts, namely the preservation of culture as an element of priority-level goals to be achieved in the development of Sade Hamlet as a tourist village at 0,476. While the determination of the level of the main criteria in the achievement of these objectives is the highest weight while maintaining a typical village environment at 0.319. Priority strategies that get the highest weight of the experts is that Sade Hamlet Revitalization with a priority weighting of 0.583. The second priority is the relocation of Hamlet at 0.235. Lowest weighting or last priority is Replication Sade Hamlet at 0.182.

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