scholarly journals Geological-petrophysical characteristic of Silurian deposits of the Volyn-Podillya edge of the East-European Platform

2019 ◽  
Vol 4 (181) ◽  
pp. 17-31
Author(s):  
Ihor KUROVETS ◽  
Yulia LYSAK ◽  
Pavlo CHEPUSENKO ◽  
Stepan MYKHALCHUK ◽  
Roman-Danylo KUCHER
Keyword(s):  
Complex Structure ◽  
Correlation Coefficients ◽  
Porous Space ◽  
Regression Equations ◽  
Petrophysical Parameters ◽  
East European ◽  
Reservoir Rocks ◽  
Permeability Factor ◽  
Clay Rocks ◽  
Filtration Properties

Taking into consideration well logging of the Silurian deposits of the Volyn-Podillya plate, the materials of laboratory investigations of petrophysical parameters of reservoir rocks were analyzed and systematized. Studied were capacity-filtration properties of reservoir rocks as well as their lithological-petrographical and structural-textural features. An analysis of the distribution of petrophysical parameters of the Silurian deposits of the Volyn-Podillya plate was executed by the methods of mathematic statistics. Main statistics and correlation coefficients between individual parameters were calculated, histograms of the distribution of the porosity factor Kpor and the permeability factor Kper, volumetric weight δ and carbonation C in rocks were compiled, regression equations between parameters and their alteration with depth were formed. Petrophysical parameters of the samples available for carbonate and terrigenous rocks of Silurian were analyzed separately. Executed investigations of petrophysical properties of rocks testify that in the Silurian deposits the carbonate reservoirs with the complex structure of the porous space were distributed. A visible alteration of capacity-filtration parameters of rocks of Silurian deposits is observed with depth. Porosity of rocks decreases with depth, but permeability increases that is a confirmation of the formation of the secondary fractured-covernous porosity. Increase in the permeability factor with depth is characteristic of carbonate rocks. According to geological-geophysical data available, the reservoir rocks with better capacity-filtration properties are distributed in the zone of the barrier reef. The best reservoir parameters are characteristic of cavernous dolomites and limestones at the Lokachy area and in the region of Lutsk. Reservoir rocks of porous type are practically absent at depths over 2500 m. Here a significant role in improving of collecting properties of rocks belongs to their fracturing. Microfractures are observed in clayed limestones, marls and clay rocks. Under favourable geodynamic conditions the subvertical zones of disconsolidation occur in which composite reservoir rocks with fracture porosity may be formed.

Heat Power Determination of Dv-290 Refrigerator’s Evaporator on the Basis of Thermodynamic Parameters of Inlet Air / Określenie Mocy Cieplnej Parownika Chłodziarki Dv-290 Na Podstawie Parametrów Termodynamicznych Powietrza Wlotowego

2012 ◽  
Vol 57 (4) ◽  
pp. 911-920
Author(s):  
Bernard Nowak ◽  
Zbigniew Kuczera
Keyword(s):  
Thermodynamic Parameters ◽  
Thermal Power ◽  
Correlation Coefficients ◽  
Specific Humidity ◽  
Physical Parameters ◽  
Air Cooling ◽  
Regression Equations ◽  
Evaporation And Condensation ◽  
Before And After ◽  
The Given

Abstract The present paper introduces a method for calculating the thermal power of DV-290 mining air cooler’s evaporator. The power usually differs from the nominal power given by the manufacturer. The thermodynamic parameters of cooled air are not obtained as a result of in situ measurements, but in indirect manner that is by determining the evaporation and condensation’s pressure values of R407C refrigerant. The pressure dependencies formulated as a function of air enthalpy at the evaporator’s inlet were obtained using calculations of a computer program which solves the system of equations describing heat and mass transfer in the refrigerator’s compressor on the basis of previous measurements of air performed before and after its cooling. The obtained dependencies are demonstrated in a graphical (fig. 2 and fig. 3) and analytical (the regression equations (19) and (20)) manner, the values of correlation coefficients are also presented. For the known evaporation and condensation pressure values of the refrigerant, and thus for its basic physical parameters the complete thermal power of the evaporator was determined, that is its: air cooling overt power, dehumidification occult power, temperature, relative humidity and specific humidity of air after its cooling. In addition, using the mentioned method, the capacity of DV-290 refrigerator’s evaporator is provided for the given thermodynamic parameters of air before cooling, along with air thermodynamic parameters after cooling.

scholarly journals Types of Void Space in the Bazhenov Reservoir Rocks

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 269
Author(s):  
Olga V. Postnikova ◽  
Alexander V. Postnikov ◽  
Olga A. Zueva ◽  
Artem E. Kozionov ◽  
Ekaterina V. Milovanova ◽  
...  
Keyword(s):  
Western Siberia ◽  
Distribution Patterns ◽  
Void Space ◽  
X Ray Diffraction ◽  
Bazhenov Formation ◽  
Reservoir Rocks ◽  
Oil Reserves ◽  
Light Oil ◽  
Clay Rocks ◽  
High Degree

The deposits of the Bazhenov formation are a unique reservoir of unconventional oil reserves in Western Siberia. They contain both solid organic matter (kerogen) and liquid light oil. The successful development of these hydrocarbons is largely determined by the adequacy of the void space models. The aim of the study is to identify the types of void space in the sediments of the Bazhenov formation and to identify the distribution patterns across the section of the researched wells. The void space was studied by electron and optical microscopy, and the mineral composition of the rocks was determined by X-ray diffraction analysis. The deposits of the Bazhenov productive formation in the territory of Western Siberia are represented by a wide complex of lithotypes, including various kinds of silicites, carbonate, clay rocks, and mixtites. The reservoir space in the reservoir rocks of the Bazhenov formation is a complex and hierarchically subordinated system, which includes voids and fractures of various sizes, configurations, and genesis. The void space of the Bazhenov formation is characterized by a fairly high degree of spatial heterogeneity, which is controlled by lithological, facies, and tectonic factors, as well as the direction of catagenetic processes.

scholarly journals Standing crops of dominant combretum species at three browsing levels in the Kruger National Park

Koedoe ◽  
1978 ◽  
Vol 21 (1) ◽  
Author(s):  
B.R. Dayton
Keyword(s):  
National Park ◽  
Correlation Coefficients ◽  
Kruger National Park ◽  
Total Biomass ◽  
Regression Equations ◽  
Stem Height ◽  
Basal Diameter ◽  
Independent Variable ◽  
Combretum Apiculatum ◽  
Different Levels

In red bushwillow veld near the Sand River in the Kruger National Park, Republic of South Africa, a determination was made of the standing crops of Combretum apiculatum and C. zeyheri at browsing levels delineated by the maximum feeding heights of impala (1,5 m), kudu (2,5 m) and giraffe (5,5 m). Using harvested sample trees, logarithmic or linear regression equations were generated which related basal diameter or stem height to biomass or percentage of total biomass at the different levels. Biomass was divided into two components: current shoots and wood plus bark. Regression forms and variables which produced the highest correlation coefficients changed with changes in species or browsing level, however, most equations were logarithmic with basal diameter as the independent variable.

scholarly journals Analysis of filtration and electrical properties anisotropy of terrigenous reservoir rocks (for DDB axial zone reservoirs)

2019 ◽  
Keyword(s):  
Electrical Resistivity ◽  
Gas Permeability ◽  
Vertical Direction ◽  
Absolute Permeability ◽  
Electrical Anisotropy ◽  
Reservoir Rocks ◽  
Vertical Permeability ◽  
Irreducible Water Saturation ◽  
Horizontal Permeability ◽  
Filtration Properties

The paper focuses on the filtration and electrical anisotropy coefficients and relationship between vertical and horizontal permeability in sandstone reservoir rocks. Field case study of DDB reservoir rocks. Petrophysical properties and parameters are estimated from core and log data from a Moscovian and Serpukhovian stages of Dnipro-Donetsk Basin (West-Shebelynka area well 701-Bis and South-Kolomak area well 31). Routine core analysis included estimation of absolute permeability, open porosity, irreducible water saturation and electrical resistivity (on dry and saturated by mineralized solution) of 40 core samples along two orthogonal directions. Shale fraction is estimated using well logging data in wells which are analyzed. The authors report that reservoir rocks are represented by compacted poor-porous (φ <10 %), low permeable (k<1mD) laminated sandstone with different ratios of clay minerals (Vsh from 0,03 to 0,7) and high volume of micaceous minerals (in some cases 20-30 %). Research theory. One of the main objectives of the work is to develop empirical correlation between vertical permeability and other capacitive and filtration properties for compacted sandstone reservoirs. A modified Kozeny-Carman equation and the concept of hydraulic average radius form the basis for the technique. Results. Coefficients of the anisotropy of gas permeability (IA) and electrical resistivity (λ) are defined based on the results of petrophysical studies. The experiments proved that IA lies in a range from 0,49 to 5 and λ from 0,77 to 1,06. Permeability and electrical resistivity anisotropy in most cases have horizontal distribution. It has been shown that in West-Shebelynka area sample №1 (depth 4933 m) there is probably no fluids flow in vertical direction and in samples №№3 and 15 fractures have the vertical orientation. We have also found that the values of electrical and filtration anisotropy for all samples of South-Kolomak area are similar, this characterized the unidirectionality in their filtration properties, as well as the fact that the motion of the fluid flow mainly in the horizontal direction. In the studied rocks the degree of anisotropy has been concluded to depend on the volume of clay and micaceous minerals, their stratification, fractures, density, and their orientation. New correlation between vertical permeability, horizontal permeability and effective porosity are developed for Late Carboniferous DDB intervals that are analyzed.

scholarly journals COMPARATIVE ANALYSIS OF DIFFERENT CRITERIA OF SITE STRUCTURAL STABILITY IN THE TIME SERIES

2019 ◽  
pp. 119-128
Author(s):  
Liliya Andreevna Landman ◽  
Andrei Vladimirovich Faddeenkov
Keyword(s):  
Time Series ◽  
Regression Model ◽  
Structural Changes ◽  
Least Squares Method ◽  
Complex Structure ◽  
Standard Normal Distribution ◽  
Regression Equations ◽  
Unknown Parameters ◽  
Chow Test ◽  
Wide Range

The concept of structure is used to describe a set of stable relations between the main parts of the object, which describe its integrity and identity, i.e, preserving the basic properties for a wide range of internal and external changes. This concept usually relates to the concepts of system and organization. The structure expresses a stable part of the system that is slightly changed during different reforms. Over the years structural changes take place because of active economic policy or as a result of spontaneous, uncontrollable processes. Therefore, it seems to be quite natural to find out whether there have been structural changes in the observation period, and to find them reflected in the specification of the model. The basic ideas of methods for determining structural changes in the time series dynamics have been considered, such as Chow test, Gujarati test and Poirier method. The power study was conducted for the three possible cases of change in time series trends. The random error was modeled according to the standard normal distribution. A linear multiple regression model with three independent variables was used as a time series model. Estimation of the vector of unknown parameters of the model was conducted using least squares method. For each of the three criteria the of test the null hypothesis about time series instability was carried out using the F -criterion, which involves finding the residual sum of squares of a regression model and analysis of correlation between its decline and the loss of degrees of freedom. It can be noted that Gujarati and Poirier equations have a more complex structure than equation of Chow test; however, using Chow test assumes estimation of the parameters of the three regression equations.

scholarly journals INFLUÊNCIA DA TEXTURA E PROFUNDIDADE DO SOLO NA CALIBRAÇÃO DA SONDA DE NÊUTRONS

Irriga ◽  
1998 ◽  
Vol 3 (1) ◽  
pp. 6-12
Author(s):  
Reginaldo Ferreira Santos ◽  
Reimar Carlesso
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Correlation Coefficients ◽  
Regression Equations ◽  
Transparent Plastic ◽  
Neutron Probe ◽  
Calibration Curves ◽  
Santa Maria

INFLUÊNCIA DA TEXTURA E PROFUNDIDADE DO SOLO NA CALIBRAÇÃO DA SONDA DE NÊUTRONS   Reginaldo Ferreira SantosDepartamento de Engenharia Rural - UNESP, CP: 237 - CEP:18603 970, Botucatu, SP Reimar CarlessoDepartamento de. Engenharia da Universidade Federal de Santa Maria, - UFSM, Campus Universitário, CEP: 97119 900, Santa Maria - RS  1 RESUMO A sonda de nêutrons é um equipamento usado na determinação do conteúdo de água do solo baseado no espalhamento e atenuação de nêutrons rápidos. Para tanto, há necessidade de calibração no campo e, conseqüentemente, verificar a influência da textura e da profundidade do solo e determinar as curvas de calibração em relação ao conteúdo de umidade. O trabalho foi desenvolvido na Universidade Federal de Santa Maria em um conjunto de lisímetros, protegidos das precipitações pluviométricas com plástico transparente. Foram usados três solos de diferentes texturas e quatro repetições e em três profundidades (10, 30 e 50 cm) a partir da superfície do solo. Foram determinadas as equações de regressão lineares entre as contagens propiciadas pela sonda e o conteúdo de umidade do solo respectivos pelo método gravimétrico. Os resultados demonstraram que houve interferência da textura e da profundidade do solo, analisados conjuntamente, nas curvas de calibração, sendo que os valores observados e os estimados variaram entre 0,02 e 0,06 cm3/ cm3 do conteúdo de água do solo e os coeficientes de correlação foram 0,86, 0,95 e 0,89 para os solos de textura argilosa, franco-argilo-siltoso e franco-arenoso, respectivamente. Já para os fatores textura e profundidade dos solos, analisados separadamente, as diferenças entre os valores observados no campo e os estimados, variaram entre 0,0 e 0,02 cm31cm3 do conteúdo de água do solo e apresentaram coeficientes de correlação entre 0,97 e 1,0. UNITERMOS: sonda de nêutrons. umidade do solo. textura e profundidade do solo  SANTOS, R.F., CARLESSO, R. Soil texture and depth influence on the neutron probe calibration   2 SUMMARY  The neutron probe is an equipment used on determination of the soil water content, based on the fast neutron attenuation. Therefore, there is a calibration need in the field and, consequently, to verify the soil texture and depth influence for to determining the calibration curves in relation to the water content. The study was developed at Santa Maria's Federal University in a lisímeter group, protected from the rains with transparent plastic. Three different soil textures, three depths (10, 30 and 50 cm from the soil surface) and four replicates were used. Linear regression equations between neutron counts and soil water contents were made. The results showed that there was interference of the texture and depth of the soil, analyzed jointly, on the calibration curves, and the observed and estimated values varied from 0,02 to 0,06 cm3 / cm3 of the soil water content and the correlation coefficients were 0,86, 0,95 and 0,89 for clayay, franc-silt-clayay and franc-sandy, respectively. For soil texture and depth, analyzed separately, the differences among the values observed in the field and the estimated ones, varied from 0,0 to 0,02 cm3/cm3 soil water content and presented correlation coefficients between 0,97 and 1,0. KEYWORDS: neutron probe, soil water content, soil texture and depth.

scholarly journals Morphological characterization of Arab and Oromo goats in northwestern Ethiopia

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Oumer Sheriff ◽  
Kefyalew Alemayehu ◽  
Aynalem Haile
Keyword(s):  
Body Weight ◽  
Coat Color ◽  
Strong Association ◽  
Correlation Coefficients ◽  
Field Research ◽  
Morphological Characterization ◽  
The Body ◽  
Regression Equations ◽  
Body Measurements ◽  
Chest Girth

Abstract Background An exploratory field research was conducted in northwestern Ethiopia, to characterize the morphological features of Arab and Oromo goat populations as an input to design community-based breeding programs. Ten qualitative and nine quantitative traits were considered from 747 randomly selected goats. All data collected during the study period were analyzed using R statistical software. Results Plain white coat color was predominantly observed in Arab goats (33.72%) while plain brown (deep and light) coat color was the most frequent in Oromo goats (27.81%). The morphometric measurements indicated that Oromo goats have significantly higher body weight and linear body measurements than Arab goats. Positive, strong and highly significant correlations were obtained between body weight and most of the body measurements in both goat populations. The highest correlation coefficients of chest girth with body weight for Arab (r  =  0.95) and Oromo (r  =  0.92) goat populations demonstrated a strong association between these variables. Live body weight could be predicted with regression equations of y  =  − 33.65  +  0.89  ×  for Arab goats (R2  =  90) and y  =  − 37.55  +  0.94  ×  for Oromo goats (R2  =  85), where y and x are body weight and chest girth, respectively, in these goat types. Conclusions The morphological variations obtained in this study could be complemented by performance data and molecular characterization using DNA markers to guide the overall goat conservation and formulation of appropriate breeding and selection strategies.

scholarly journals TANAKA AND JOHNSTON'S MIXED DENTITION VALIDITY: AN ANALYSIS AMONG YEMENI ADULTS IN SANA'A CITY

2022 ◽  
Author(s):  
Waleed Abdualaziz Mohammad Dahag ◽  
Abdulwahab Ismail Mohamed Al-Kholani ◽  
Taghreed Ahmed M Al-Kibsi ◽  
Hussein Shoga Al-Deen ◽  
Hassan Abdulwahab Al-Shamahy ◽  
...  
Keyword(s):  
Peer Review ◽  
School Children ◽  
Correlation Coefficients ◽  
T Test ◽  
Mixed Dentition ◽  
Primary School Children ◽  
Regression Equations ◽  
Chi Square ◽  
Anterior Teeth ◽  
Tooth Width

Introduction and objective: Mixed dentition space analysis methods via Tanaka-Johnston analysis are regularly used all over the world. Conversely, the appropriate of this analysis between different ethnic groups is dubious. The study aimed to test the appropriate of the Tanaka-Johnston analysis for Yemeni adults and to arise regression equations designed for Yemen population if needed.  Methods: The study included two hundred and twenty-seven (106 males and 121 females) Yemenis from Sana'a University, University of Science and Technology, and Al-Rehab Private Clinic. The mesiodistal widths of the four permanent lower canines, incisors, and premolars for the entire quadrants were determined with a digital caliper to the nearest 0.01 mm. To compare average presentation values ​​derived from this study with values ​​derived using Tanaka-Johnston equations, Student's paired t-test was used, as well as the chi-square (χ2) test used for appropriateness of fit. Result: Gender differences were observed in the total mesiodistal width of both canines and premolars in both arches as revealed by the t-test (p < 0.001). The sum of the actual mesiodistal width of the canines and premolars was compared with the expected widths derived from the Tanaka and Johnston equation and significant differences (p<0.001) were found. Regression analysis indicated that the sum of the mesiodistal width of the permanent mandibular incisors is a good predictor of that of un-erupted canines and premolars, with correlation coefficients ranging from 0.51 to 0.61. Accordingly, two linear regression equations were developed to predict tooth width for Yemeni males and females. Conclusion: It was concluded from this study that the Tanaka-Johnston analysis did not accurately predict the mesiodistal width of the unruptured canines and premolars of the Yemeni population. Moreover, new regression equations have been developed for the research sample that can be a standard for Yemen. However, further studies must be performed to verify the applicability and accuracy of these equations.                   Peer Review History: Received: 10 November 2021; Revised: 12 December; Accepted: 29 December, Available online: 15 January 2022 Academic Editor: Dr. Asia Selman Abdullah, Pharmacy institute, University of Basrah, Iraq, [email protected] UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency.  Received file:                Reviewer's Comments: Average Peer review marks at initial stage: 6.5/10 Average Peer review marks at publication stage: 7.5/10 Reviewers: Dr. A.A. Mgbahurike, University of Port Harcourt, Nigeria, [email protected] Rola Jadallah, Arab American University, Palestine, [email protected] Similar Articles: PREVALENCE AND CAUSES OF TRAUMATIC DENTAL INJURIES TO ANTERIOR TEETH AMONG PRIMARY SCHOOL CHILDREN IN SANA'A CITY, YEMEN OCCLUSAL CHARACTERISTICS OF THE PRIMARY DENTITION AMONG A SAMPLE OF YEMENI PRE-SCHOOL CHILDREN

DISTRIBUTION OF MERCURY IN COAL SEAM C7н OF PAVLOHRADSKA MINE FIELD

2020 ◽  
pp. 26-33
Author(s):  
Valerii Ishkov ◽  
◽  
Yevhen Kozii
Keyword(s):  
Coal Seam ◽  
Raw Materials ◽  
Weighted Average ◽  
Correlation Coefficients ◽  
Industrial Area ◽  
Mercury Content ◽  
Ash Content ◽  
Practical Significance ◽  
Regression Equations ◽  
Mine Field

Purpose. Investigation of regularities of mercury distribution in coal of formation c7n of the Pavlogradska mine field. Methodology. Method of atomic absorption analysis of furrow samples of wells. Processing of geochemical and structural-geological data by methods of mathematical statistics using Excel 2016 and Statistica 6.0. The computer program Surfer was used to build maps/ Results. In article considered the distribution of mercury in the coal seam c7н of the Pavlohradska mine field of the Pavlohrad-Petropavlivka geological and industrial district of Donbas. As a result of the study, a map of isoconcentrates and a map of the regional component of mercury content in the coal of the seam were constructed and analyzed. Correlation coefficients between mercury concentration and formation morphological parameters and coal sulfur were calculated. The regression equations between this element and the ash content of coal are also established, which will allow predicting their concentration in the main working coal seams of the geological-industrial area relative to the values of coal ash content. The nature of sulfur distribution is established and the weighted average concentrations and the main descriptive statistics of this element are calculated. Scientific novelty. Peculiarities and regularities of mercury accumulation in coal of formation c7n are revealed. Practical significance. The constructed maps and established correlations are the factual basis for long-term forecasting of mercury concentrations in extracted raw materials and adjustment of technological schemes of coal beneficiation. Keywords: mercury, mine, coal height, ash content, stratum depth, sulfur content, regression equation, correlation coefficient.

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