scholarly journals Methods of statistical analysis stationary kinetic model ideal mixing cell

2019 ◽  
Vol 80 (4) ◽  
pp. 133-137
Author(s):  
V. M. Zarochentsev ◽  
T. V. Kondratenko ◽  
A. K. Makoeva
Keyword(s):  
Statistical Analysis ◽  
Kinetic Model ◽  
Simulation Model ◽  
Flow Reactor ◽  
Mutual Influence ◽  
Chemical Interaction ◽  
Model Identification ◽  
Ideal Mixing ◽  
Perfect Mixing ◽  
Statistical Analysis Method

The article describes the statistical analysis method of the stationary kinetic model of perfect mixing cell which can be applied to devices using spatial combination of perfect mixing cells. A simulation model of interaction of two substances in a continuous-flow reactor of perfect mixing and graphs of chemical interaction of the substances is elaborated. A parametric simulation model identification method of least squares is conducted. The adequacy of the model obtained using the F-test and the hypothesis of heterogeneity of variances of random processes and functions is evaluated. The possible intervals of the linear zed equation coefficients using t-test are significance estimated coefficients are determined for the chosen form of the equation. The obtained values of the possible intervals are caused by in the stochastic factors simulation model by and mutual influence of deviations of different parameters. The calculation results are shown in Example 1 and Example 2. The relative error for output concentration was more than 10%. Therefore averaging over five repeated observations at each point in order to reduce the dispersion was performed. The averaged values of the parameters are suitable for the simulation and analysis processes. The results of research can be used for the development of mathematical modeling methods and analysis in fixed-chemical processes occurring in solutions.

scholarly journals Financial Performance of Non-oil Manufacturing Companies Listed on the Libyan Stock Market (LSM): Mixed Methods Study

2019 ◽  
Vol 9 (4) ◽  
pp. 77
Author(s):  
Khalifa Mohamed Khalifa Omar
Keyword(s):  
Statistical Analysis ◽  
Stock Market ◽  
Financial Performance ◽  
Manufacturing Companies ◽  
Analysis Method ◽  
Affecting Factors ◽  
Structured Interviews ◽  
Turnover Ratio ◽  
Statistical Effect ◽  
Statistical Analysis Method

The major objective of this study is to assess the financial performance and identify the affecting factors in this performance of non-oil manufacturing companies from 1999 to 2008. The study sample consisted of all non-oil manufacturing companies' enlisted at Libyan stock market which count (8). The data collected was analyzed by using statistical analysis method such as descriptive statistics, correlation test, Multiple- regression, as well as semi-structured interviews method. The results regarding to the statistical analysis method (net working capital, inventory turnover ratio, selling and general administrative expenses ratio, and company size and company age), have a positive statistical effect on the financial performance(ROA), while the variables of (current ratio, quick ratio and account receivable turnover ratio), have a negative statistical effect on the financial performance (ROA). The results regarding to semi-structured interviews method, reveal that the respondents in the interviews were confirmed that the selected factors have a significant effect on financial performance (ROA). The researcher recommended that the selected companies must consider the listed decision on the Libyan stock market; even when their financial performance is good.

scholarly journals Variability of Prognostic Results Based on Biological Parameters in Sickle Cell Disease Cohort Studies in Children: What Should Clinicians Know?

Children ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 143
Author(s):  
Julie Sommet ◽  
Enora Le Roux ◽  
Bérengère Koehl ◽  
Zinedine Haouari ◽  
Damir Mohamed ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Sickle Cell Disease ◽  
Cohort Studies ◽  
Statistical Methods ◽  
Sickle Cell ◽  
Biological Parameters ◽  
Analysis Method ◽  
Cell Disease ◽  
Statistical Analysis Method

Background: Many pediatric studies describe the association between biological parameters (BP) and severity of sickle cell disease (SCD) using different methods to collect or to analyze BP. This article assesses the methods used for collection and subsequent statistical analysis of BP, and how these impact prognostic results in SCD children cohort studies. Methods: Firstly, we identified the collection and statistical methods used in published SCD cohort studies. Secondly, these methods were applied to our cohort of 375 SCD children, to evaluate the association of BP with cerebral vasculopathy (CV). Results: In 16 cohort studies, BP were collected either once or several times during follow-up. The identified methods in the statistical analysis were: (1) one baseline value per patient (2) last known value; (3) mean of all values; (4) modelling of all values in a two-stage approach. Applying these four different statistical methods to our cohort, the results and interpretation of the association between BP and CV were different depending on the method used. Conclusion: The BP prognostic value depends on the chosen statistical analysis method. Appropriate statistical analyses of prognostic factors in cohort studies should be considered and should enable valuable and reproducible conclusions.

Ignition Characteristics of a Fischer-Tropsch Synthetic Jet Fuel

2008 ◽  
Author(s):  
P. Gokulakrishnan ◽  
M. S. Klassen ◽  
R. J. Roby
Keyword(s):  
Kinetic Model ◽  
Ignition Delay ◽  
Flow Reactor ◽  
Kinetic Mechanism ◽  
Jet Fuel ◽  
Synthetic Jet ◽  
Jet Fuels ◽  
Ignition Delay Times ◽  
Delay Times ◽  
Ignition Characteristics

Ignition delay times of a “real” synthetic jet fuel (S8) were measured using an atmospheric pressure flow reactor facility. Experiments were performed between 900 K and 1200 K at equivalence ratios from 0.5 to 1.5. Ignition delay time measurements were also performed with JP8 fuel for comparison. Liquid fuel was prevaporized to gaseous form in a preheated nitrogen environment before mixing with air in the premixing section, located at the entrance to the test section of the flow reactor. The experimental data show shorter ignition delay times for S8 fuel than for JP8 due to the absence of aromatic components in S8 fuel. However, the ignition delay time measurements indicate higher overall activation energy for S8 fuel than for JP8. A detailed surrogate kinetic model for S8 was developed by validating against the ignition delay times obtained in the present work. The chemical composition of S8 used in the experiments consisted of 99.7 vol% paraffins of which approximately 80 vol% was iso-paraffins and 20% n-paraffins. The detailed kinetic mechanism developed in the current work included n-decane and iso-octane as the surrogate components to model ignition characteristics of synthetic jet fuels. The detailed surrogate kinetic model has approximately 700 species and 2000 reactions. This kinetic mechanism represents a five-component surrogate mixture to model generic kerosene-type jets fuels, namely, n-decane (for n-paraffins), iso-octane (for iso-paraffins), n-propylcyclohexane (for naphthenes), n-propylbenzene (for aromatics) and decene (for olefins). The sensitivity of iso-paraffins on jet fuel ignition delay times was investigated using the detailed kinetic model. The amount of iso-paraffins present in the jet fuel has little effect on the ignition delay times in the high temperature oxidation regime. However, the presence of iso-paraffins in synthetic jet fuels can increase the ignition delay times by two orders of magnitude in the negative temperature (NTC) region between 700 K and 900 K, typical gas turbine conditions. This feature can have a favorable impact on preventing flashback caused by the premature autoignition of liquid fuels in lean premixed prevaporized (LPP) combustion systems.

Fouling Tendency of Ash Resulting From Burning Mixtures of Biofuels

2005 ◽  
Author(s):  
Mischa Theis ◽  
Bengt-Johan Skrifvars ◽  
Mikko Hupa ◽  
Honghi Tran
Keyword(s):  
Flow Reactor ◽  
Chemical Interaction ◽  
Substrate Surface ◽  
Agricultural Waste ◽  
Pulp Mill ◽  
Considerable Change ◽  
Chemical Fractionation ◽  
Feed Composition ◽  
Linear Pattern ◽  
Fractionation Analysis

Specified mixtures of peat with bark and peat with straw were burned in a lab-scale entrained flow reactor that simulates conditions in the superheater region of a biomass-fired boiler. Deposits were collected on an air-cooled probe that was inserted into the reactor at the outlet. For both mixtures, the deposition behaviour followed a non-linear pattern, which suggests that physico-chemical interaction between the ashes of the different fuels has taken place. The results indicate that it is possible to burn up to 30 wt-% bark (renewable biofuel and pulp mill waste) and up to 70 wt-% straw (renewable biofuel and agricultural waste) in mixtures with peat without encountering increased deposition rates in the reactor. The deposit composition was compared to the fuel ash composition using chemical fractionation analysis and SEM/EDX. While the composition of deposits obtained from pure fuels resembles the feed composition, a considerable change is observed in deposits obtained from mixtures. K and S compounds are attached to Si spheres and the substrate surface. The deposition rate is significantly lowered when removing K, S, Cl and Na in bark prior to burning by washing and mechanical/thermal dewatering.

scholarly journals The role of scientific research in achieving economic development Applied to White Nile state- Sudan (2015- 2018): دور البحث العلمي في تحقيق التنمية الاقتصادية دراسة ميدانية في ولاية النيل الأبيض – السودان (للفترة من 2015م - 2018م)

2020 ◽  
Vol 4 (7) ◽  
Author(s):  
Mahdi Abdalla Mohamed, Musa Abdalla Mohamed
Keyword(s):  
Economic Development ◽  
Statistical Analysis ◽  
Scientific Research ◽  
Analysis Method ◽  
Important Target ◽  
Statistical Analysis Method ◽  
White Nile ◽  
Descriptive Method

The study is focusing on the factors which are leading to know the weakness link between the scientific research and economic development in the White Nile state. The important target of the study is to determinate the role of scientific research in the economic development. The study dependence on the statistical analysis method, historical and descriptive method. It aims to collect information related to the problem. The most important result of the study that state has significant savings in production. The most important recommendations of the study the necessity of using scientific research to achieve economic development.

scholarly journals Modeling of diversification of foreign economic interactions

2018 ◽  
Vol 16 (1) ◽  
pp. 155-165
Author(s):  
Ihor Hroznyi ◽  
Oleh Kuzmak ◽  
Olena Kuzmak ◽  
Olha Rusinova
Keyword(s):  
Dynamic System ◽  
Simulation Model ◽  
Mutual Influence ◽  
Model Development ◽  
Complex Dynamic ◽  
Complex Dynamic System ◽  
World Markets ◽  
Economic Interactions ◽  
Simulation Package

The article developed a basic simulation model of diversification of foreign economic interactions, which makes it possible to assess the mutual influence of key economic indicators and their reaction to changes in the equilibrium in world markets. The peculiarity of the developed model of diversification of foreign economic interactions is its functioning as a complex dynamic system in which many factors are interrelated, and the connections are dynamic. This makes it possible to calculate a simulation model that takes into account hidden and subtle connections. While modeling foreign economic interactions and evaluating the influence of various regulators on them, in addition to the stage of model development itself, mandatory parameterization of this model is proposed, that is, the determination of specific types of dependence between the factors included in the model and the parameters of these dependencies. The implementation of this model can be carried out in any simulation package.

Test Reliability of Impurity Parameters of Uster AFIS

2011 ◽  
Vol 331 ◽  
pp. 516-527
Author(s):  
Peng Zi Sun ◽  
Ji Peng Cao
Keyword(s):  
Statistical Analysis ◽  
Test Reliability ◽  
Test Time ◽  
Test Results ◽  
Analysis Method ◽  
Sample Weight ◽  
Reliable Test ◽  
Sampling Process ◽  
Statistical Analysis Method ◽  
Card Sliver

This paper presents test reliablity of Uster AFIS for impurity test by calculating the Reliable Test Time (hereinafter referred to as RTT) and CV% of test results. The CV% value of test results of impurity-related parameters in card sliver obtained in 8 experiments totally with 313 different plans were calculated. By statistical analysis method, the reliable test time of AFIS for some impurity-related parameters was estimated. It is concluded that the impurity result obtained by 10-time tests with AFIS was inaccurate. The reasons for this are that the sample weight is too small, the impurity is unevenly distributed and the impurity in card sliver may have some loss in the manually-sampling process.

Statistical Analysis Method for Literature Information

Informetrics ◽  
2017 ◽  
pp. 185-206
Author(s):  
Junping Qiu ◽  
Rongying Zhao ◽  
Siluo Yang ◽  
Ke Dong
Keyword(s):  
Statistical Analysis ◽  
Analysis Method ◽  
Literature Information ◽  
Statistical Analysis Method
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