scholarly journals NUMERICAL SIMULATION OF INITIAL PRESSURE EFFECT ON ENERGY INPUT IN SPARK DISCHARGE IN NITROGEN

2019 ◽  
Author(s):  
K.V. Korytchenko ◽  
R.S. Tomashevskyi ◽  
I.S. Varshamova ◽  
D.P. Dubinin ◽  
A.A. Lisnyak ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Energy Input ◽  
Energy Deposition ◽  
Pressure Effect ◽  
Initial Pressure ◽  
Spark Discharge ◽  
Atmospheric Conditions ◽  
Energy Correlation ◽  
Average Value ◽  
Spark Channel

An influence of initial gas pressure on energy deposited by spark discharge in nitrogen during the spark channel expansion is evaluated. Influence of the pressure on efficiency of energy deposition and emitted energy in a discharge channel is simulated. Dependencies of dynamic of energy input and an energy correlation coefficient on the pressure are found out. It was suggested to use an average value of the correlation coefficient to model a load of spark channel by the any initial pressure when a spark load is formed by atmospheric conditions.

scholarly journals EXPERIMENTAL AND NUMERICAL STUDIES OF PRESSURE AND GAP LENGTH EFFECTS ON ENERGY DEPOSITION IN SPARK DISCHARGE

2021 ◽  
pp. 92-97
Author(s):  
K.V. Korytchenko ◽  
I.S. Varshamova ◽  
D.V. Meshkov ◽  
D.P. Dubinin ◽  
R.I. Kovalenko ◽  
...  
Keyword(s):  
Energy Input ◽  
Energy Deposition ◽  
Initial Pressure ◽  
Numerical Studies ◽  
Voltage Probe ◽  
Spark Channel ◽  
Discharge Gap ◽  
Total Discharge ◽  
Channel Development

A study of the influence of the discharge gap length and the initial gas pressure on the energy deposition into the discharge channel was done. The study was conducted at the same total discharge energy. It is experimentally shown that the connection of the voltage probe to the discharge circuit significantly affects the discharge current. The determination of the energy deposited into the spark channel is based on the results of numerical simulation of the spark channel development. Experimentally measured discharge currents at different pressures and the gap length were used as initial data for the calculation. Based on the obtained results, it is determined which of the factors (the initial pressure or the gap length) has the strongest influence on the energy input into the spark channel.

scholarly journals Numerical simulation of gap length influence on energy deposition in spark discharge

2021 ◽  
pp. 35-43
Author(s):  
K.V. Korytchenko ◽  
O.V. Shypul ◽  
D. Samoilenko ◽  
I.S. Varshamova ◽  
А.A. Lisniak ◽  
...  
Keyword(s):  
Total Energy ◽  
Linear Relationship ◽  
Discharge Current ◽  
Energy Input ◽  
Discharge Channel ◽  
Spark Discharge ◽  
Gas Dynamic ◽  
Spark Gap ◽  
Deposited Energy ◽  
Spark Channel

The aim of the work is to study the influence of the length of the spark gap on energy input into the discharge channel during its gas-dynamic expansion. Methodology. The research is carried out by numerical modeling of the process of spark discharge development at variable values of the discharge gap length and at invariable other discharge conditions. The length of the gap was set in the range from 1 mm to 20 mm. The study was conducted using a numerical model of spark development, which takes into account the processes of nonstationary gas-dynamic expansion of the spark channel, the transient process in the electric circuit, nonequilibrium chemical processes, gas ionization, heat transfer and electrons thermal conductivity. The simulation was performed in atmospheric pressure nitrogen. The calculation was performed for various parameters of the RLC circuit, such as capacitance, inductance, resistance and voltage across the capacitor. Results. The study evaluates the influence of the spark length on the discharge current, the resistance of the spark channel, the energy deposited in the spark channel, and the distribution of thermodynamic parameters of the gas during the development of the spark discharge. It is confirmed that increasing the length of the gap increases the resistance of the spark. The deviation from the linear relationship between the deposited energy or the radiated energy and the length of the spark gap is estimated. Scientific novelty. A linear relationship between the gap length and the deposited energy is revealed when the total energy is above tens of Joules. Deviations from the linear dependence were detected in the discharge circuit when the total energy is below one of Joules. Practical value. The research results allow predicting the effect of the spark gap length on the energy input into the discharge channel under conditions of a slight change in the discharge current. In the conditions of essential change of amplitude of discharge current it is expedient to apply numerical researches for specification of changes in the energy deposited into a spark discharge.

IMBALAN DAN GAYA KEPEMIMPINAN PENGARUHNYA TERHADAP KEPUASAN KERJA KARYAWAN DI BALAI BESAR INDUSTRI HASIL PERTANIAN BOGOR

2018 ◽  
Vol 1 (01) ◽  
pp. 17
Author(s):  
Ramlan Ruvendi
Keyword(s):  
Job Satisfaction ◽  
Multiple Regression ◽  
Correlation Coefficient ◽  
Analysis Of Variance ◽  
Partial Correlation ◽  
Multiple Correlation Coefficient ◽  
Multiple Correlation ◽  
Average Value ◽  
Partial Correlation Coefficient

The study was carried out to find out whether there were influence and correlation bet-ween : a) Reward received by the IRDABI’s employees on their job satisfaction. b) style of the leader-ship on the job satisfaction. c) Reward together with style of leadership on the job satisfaction of IR-DABI’s employees.The result of the study showed that there was significant correlation and influence between the reward on the job satisfaction with was shown by the value of partial correlation coefficient of 0.6185 and coefficient of multiple regression for reward variable (β1) of 0.412. The influence of variable for style of leadership on the job satisfaction was also significant with the partial correlation coefficient of 0.5495 and coefficient of multiple regression (β2) of 0.355.In the test of Analysis of Variance (ANOVA) on the equation of multiple regression show that F-value was bigger that F-table (F = 58.97 > F-table = 3.098) or the Probability Value smaller than 0.05. At showed that there was significant correlation and influence between reward variables all together with style of leadership on the job satisfaction of employees. The value of multiple correlation coefficient (R) was 0.751 and R Square (R2) was 0.564. Value of R Square (0.564) meant that 56.5% of variation pro-portion total of job satisfaction can be eliminated of equation of multiple regression was used as the es-timator rather than using average value of job satisfaction as the estimator.

scholarly journals KORELASI ANTARA POLA PEMBINAAN AKHLAK DENGAN PERILAKU PESERTA DIDIK KELAS XI PONDOK PESANTREN DARUL AMAN GOMBARA MAKASSAR

2020 ◽  
Vol 9 (1) ◽  
pp. 46
Author(s):  
Muhammad Rusmin B
Keyword(s):  
Moral Development ◽  
Correlation Coefficient ◽  
Strong Correlation ◽  
Boarding School ◽  
T Test ◽  
Test Results ◽  
Average Value ◽  
The Relationship ◽  
Correlation Level

The results of the moral development of the students of class XI of the Darul Aman Gombara Islamic Boarding School in Makassar are quite good. This is based on a questionnaire distributed and interviews with several teachers, not found any students who have committed acts that violate the norms of behavior / morals. Behavior of students of class XI Darul Aman Gombara Makassar Islamic Boarding School which obtained the highest score was 87 and the lowest score was 67. The average value obtained from 30 students was 78.3. So it can be concluded that the behavior of students of class XI Darul Islamic Boarding School safe in Gombara Makassar is included in both categories. The relationship between moral development and the behavior of students in class XI Darul Aman Gombara Islamic Boarding School Makassar, namely the level of relationship is classified as very strong. In the correlation coefficient table and the t test results obtained rtable is 0.99> 0.361, then H0 is rejected and H1 is accepted. This can be concluded that there is a correlation or the relationship between moral development with the behavior of students of class XI Darul Aman Gombara Islamic Boarding School in Makassar, with a very strong correlation level.

scholarly journals Consistency Fuzzy Sets and a Cosine Similarity Measure in Fuzzy Multiset Setting and Application to Medical Diagnosis

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ezgi Türkarslan ◽  
Jun Ye ◽  
Mehmet Ünver ◽  
Murat Olgun
Keyword(s):  
Correlation Coefficient ◽  
Similarity Measure ◽  
Fuzzy Set ◽  
Medical Diagnosis ◽  
Uncertain Data ◽  
Cosine Similarity ◽  
Comparison Analysis ◽  
Average Value ◽  
Truth Function ◽  
Cosine Similarity Measure

The main purpose of this study is to construct a base for a new fuzzy set concept that is called consistency fuzzy set (CFS) which expresses the multidimensional uncertain data quite successfully. Our motive is to reduce the complexity and difficulty caused by the information contained in the truth sequence in a fuzzy multiset (FMS) and to present the data of the truth sequence in a more understandable and compact manner. Therefore, this paper introduces the concept of CFS that is characterized with a truth function defined on a universal set 0,1 2 . The first component of the truth pair of a CFS is the average value of the truth sequence of a FMS and the second component is the consistency degree, that is, the fuzzy complement of the standard deviation of the truth sequence of the same FMS. The main contribution of a CFS is the reflection of both the level of the average of the data that can be expressed with the different sequence lengths and the degree of the reasonable information in data via consistency degree. To develop this new concept, this paper also presents a correlation coefficient and a cosine similarity measure between CFSs. Furthermore, the proposed correlation coefficient and cosine similarity measure are applied to a multiperiod medical diagnosis problem. Finally, a comparison analysis is given between the obtained results and the existing results in literature to show the efficiency and rationality of the proposed correlation coefficient and cosine similarity measure.

scholarly journals Development of a Hybrid Lagrangian–Eulerian Model to Describe Spark-Ignition Processes at Engine-Like Turbulent Flow Conditions

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Riccardo Scarcelli ◽  
Anqi Zhang ◽  
Thomas Wallner ◽  
Sibendu Som ◽  
Jing Huang ◽  
...  
Keyword(s):  
Energy Deposition ◽  
Combustion Process ◽  
Spark Ignition ◽  
Computational Time ◽  
Ignition Process ◽  
Time Step ◽  
Eulerian Model ◽  
Constant Volume Chamber ◽  
Spark Channel ◽  
Deposition Models

With the engine technology moving toward more challenging (highly dilute and boosted) operation, spark-ignition processes play a key role in determining flame propagation and completeness of the combustion process. On the computational side, there is plenty of spark-ignition models available in literature and validated under conventional, stoichiometric spark ignition (SI) operation. Nevertheless, these models need to be expanded and developed on more physical grounds since at challenging operation they are not truly predictive. This paper reports on the development of a dedicated model for the spark-ignition event at nonquiescent, engine-like conditions, performed in the commercial CFD code converge. The developed methodology leverages previous findings that have expanded the use and improved the accuracy of Eulerian-type energy deposition models. In this work, the Eulerian energy deposition is coupled at every computational time-step with a Lagrangian-type evolution of the spark channel. Typical features such as spark channel elongation, stretch, and attachment to the electrodes are properly described to deliver realistic energy deposition along the channel during the entire ignition process. The numerical results are validated against schlieren images from an optical constant volume chamber and show the improvement in the simulation of the spark channel during the entire ignition event, with respect to the most commonly used energy deposition approach. Further developmental pathways are discussed to provide more physics-based features from the developed ignition model in the future.

scholarly journals Determination of the Key Comparison Reference Value from Multiple Field Calibration of Sentinel-2B/MSI over the Baotou Site

2020 ◽  
Vol 12 (15) ◽  
pp. 2404
Author(s):  
Caixia Gao ◽  
Yaokai Liu ◽  
Jinru Liu ◽  
Lingling Ma ◽  
Zhifeng Wu ◽  
...  
Keyword(s):  
Weighted Average ◽  
Reference Value ◽  
Atmospheric Conditions ◽  
Key Comparison ◽  
Field Calibration ◽  
Average Value ◽  
True Value ◽  
Chi Squared ◽  
Calibration Samples ◽  
Relative Differences

Field calibration is a feasible way to evaluate space-borne optical sensor observations via natural or artificial sites on Earth’s surface with the aid of synchronous surface and atmospheric characteristic data. Since field calibration is affected by the coupled effects of surface and atmospheric characteristics, the single calibration results acquired under different surface and atmospheric conditions have different biases and different uncertainties, making it difficult to determine the consistency of these multiple calibration results. In view of this, by assuming that the radiometric performance is invariant during field calibration and the calibration samples are independent of each other, the surface–atmosphere invariant Key Comparison Reference Value (KCRV) is essentially derived from various calibration results. As the number of calibration samples increases, the uncertainty in the KCRV should decrease, and the KCRV should approach the “true” value. This paper addresses a novel method for estimating a weighted average value from multiple calibration results that can be used to compare each calibration result, and this value is accepted as the KCRV. Furthermore, this method is preliminarily applied to the field calibration of the Multispectral Instrument (MSI) onboard the Sentinel-2B satellite via the desert target at the Baotou site, China. After employing a chi-squared test to verify that 12 calibration samples are independent from each other, the KCRV of the 12 calibration samples at the Baotou site is derived, which exhibits much lower uncertainty than a single sample. The results show that the KCRVs of the relative differences between the simulated and observed at-sensor reflectance are 3.75%, 5.11%, 6.09%, and 5.03% for the four bands of Sentinel-2B/MSI, respectively, and the corresponding uncertainties are 1.84%, 1.87%, 1.90%, and 1.93%. It is noted that the KCRV uncertainty obtained with only 12 calibration samples is reduced significantly, and in the future, more samples in other instrumented sites will be used to validate this method thoroughly.

Choose the Best Coach Based on the Theory of Grey System

2014 ◽  
Vol 998-999 ◽  
pp. 1757-1760 ◽  
Author(s):  
Jia Zhao
Keyword(s):  
Correlation Coefficient ◽  
Evaluation Model ◽  
Relative Size ◽  
Coefficient Matrix ◽  
Weight Matrix ◽  
Target Range ◽  
Grey System ◽  
Average Value ◽  
Dynamic Weight ◽  
Correlation Coefficient Matrix

In order to select “the best all time college coach” across both genders and all possible sports, we establish a multi-hierarchy evaluation model based on the theory of grey system. Without affecting the reliability of the results, we analyze the distribution of every index to determine the initial screening standard, narrow target range and simplify the problem. Then, we use the theory of grey system to evaluate coaches. We first normalize all indexes to make them comparable. Second, we determine a set of the best indexes as the reference vector and obtain the correlation coefficient matrix. On the issue of the weight of all indexes, we introduce the concept of dynamic weight matrix by considering the distribution and relative size of them. After that, we obtain the value of the final evaluation from the correlation coefficient matrix and dynamic weight matrix .As for the influence of time on the evaluation, we regroup the data of coaches according to the time section for five years, which results in some statistical variables, and then we draw the trend graph of them. To sum up, the number of excellent coaches of every sport is increasing over time, but the average value and standard deviation of winning percentage is decreasing. The model has the adaptability on different sports by comparison. And because the data of women coaches is insufficient, the influence of genders on the evaluation needs to be researched further.

scholarly journals The Climatology, precipitation types and atmospheric conditions of extreme precipitation events in western Turkey

2018 ◽  
Author(s):  
Bulent Oktay Akkoyunlu ◽  
Hakki Baltaci ◽  
Mete Tayanc
Keyword(s):  
Eastern Mediterranean ◽  
Balkan Peninsula ◽  
Marmara Region ◽  
Atmospheric Conditions ◽  
Pressure Center ◽  
Western Turkey ◽  
Average Value ◽  
Circulation Types ◽  
Extreme Precipitation Events ◽  
Rugged Topography

Abstract. This paper investigates the climatology, precipitation types and background physical mechanisms of extreme precipitations events (EPEs) over western Turkey during the period 2006–2015. The EPEs are described as the precipitation values above the 90th percentile obtained from the hourly precipitation dataset having high spatial resolution. Precipitation types associated with EPEs are identified by using radar outputs and Lamb Weather Type (LWT) approach. It is found that EPEs occurred more frequently in the Marmara and Aegean regions during autumn and winter months. In Marmara, mainly 21 %, 17 % and 15 % of total autumn EPEs are observed as convective (E circulation types (CTs)), cyclonic (C), and sea-effect (NE) extreme precipitations (EPs), in order. While convective EPEs are generally more active in the southern portions having rugged topography, cyclonic and sea effect EPs are more effective in the southwest and northeastern parts of Marmara. Among these three precipitation types, convective CTs produce more intense daily precipitation in the Marmara region with daily average value of 66.1 mm. Based on the hourly observations, convective types of EP which developed by the interaction between high pressure center over Balkan Peninsula and low pressure center over eastern Mediterranean, show two peak values during afternoon and evening times of the day and are linked to diurnal heating. In terms of Aegean region, cyclonic originated EPs, which include 65 % of the total winter EPEs, are more common in the whole territory and reach to its peak value during the first hours of the day.

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