scholarly journals Permeability Prediction of Sandstones Based on Mercury Intrusion Method

2022 ◽  
Vol 2152 (1) ◽  
pp. 012003
Author(s):  
Hongyi Fu
Keyword(s):  
Prediction Models ◽  
General Knowledge ◽  
Permeability Measurement ◽  
General Reference ◽  
Reservoir Evaluation ◽  
Mercury Intrusion ◽  
The Past ◽  
Permeability Prediction ◽  
The Given ◽  
Tight Rocks

Abstract The use of the mercury intrusion method has been one of the most relevant trends in determining the permeability of porous media in the past decades. In this paper, general knowledge of sandstone reservoir evaluation is delineated including the pore distribution of sandstones and air permeability measurement. Based upon the paradigmatic study conducted by Purcell, a schematic diagram illustrating apparatus used in mercury intrusion is shown and introduced, and the relevant procedure is also outlined. Four significant permeability prediction models are described respectively and compared based on researches focusing on tight rocks. By doing so, this article reveals that the performance of the models is different despite the painstaking analysis and the significance of these studies. The contribution of this present study is providing a general reference of permeability prediction by mercury intrusion method as well as its previous momentous studies, giving a comparison among the given models.

Acquiring penmanship and writing skills from the first to fifth grade of primary school: Joined-up writing vs. Comenia Script

2018 ◽  
Vol 6 (2) ◽  
pp. 1-13
Author(s):  
Olga Kučerová ◽  
Anna Kucharská
Keyword(s):  
Primary School ◽  
Error Rate ◽  
Writing Skills ◽  
Fifth Grade ◽  
Point Scale ◽  
The Past ◽  
School Year ◽  
And Gender ◽  
Developmental Dynamics ◽  
The Given

Abstract The project presented here deals with a typical human means of communication – writing. The aim of the project is to map the developmental dynamics of handwriting from the first to the fifth grade of primary school. The question remains topical because of the fact that several systems of writing have been used in the past few years. Our project focuses on comparing the systems of joined-up handwriting (the standard Latin alphabet) and the most widespread form of printed handwriting: Comenia Script. The research can be marked as sectional; pupils took a writing exam at the beginning and at the end of the 2015/2016 school year. The total number of respondents was 624 pupils, evenly distributed according to the school year, system of writing and gender. To evaluate handwriting, the evaluation scale of Veverková and Kucharská (2012) was adjusted to include a description of phenomena related to graphomotor and grammatical aspects of writing, including the overall error rate and work with errors. Each area that was observed included a series of indicators through which it was possible to create a comprehensive image of the form handwriting took in the given period. Each indicator was independently classified on a three-point scale. Thanks to that, a comprehensive image of the form of writing of a contemporary pupil emerged.

Forecasting of Tornadoes and Downbursts

2020 ◽  
Author(s):  
Djordje Romanic
Keyword(s):  
Chaos Theory ◽  
Prediction Models ◽  
Weather Prediction ◽  
Small Scale ◽  
Weather Forecasts ◽  
Wind Speeds ◽  
The Past ◽  
Extreme Wind ◽  
Extreme Wind Speeds ◽  
Numerical Weather Prediction Models

Tornadoes and downbursts cause extreme wind speeds that often present a threat to human safety, structures, and the environment. While the accuracy of weather forecasts has increased manifold over the past several decades, the current numerical weather prediction models are still not capable of explicitly resolving tornadoes and small-scale downbursts in their operational applications. This chapter describes some of the physical (e.g., tornadogenesis and downburst formation), mathematical (e.g., chaos theory), and computational (e.g., grid resolution) challenges that meteorologists currently face in tornado and downburst forecasting.

CPT-based liquefaction case histories compiled from three earthquakes in Canterbury, New Zealand

2021 ◽  
pp. 875529302199636
Author(s):  
Mertcan Geyin ◽  
Brett W Maurer ◽  
Brendon A Bradley ◽  
Russell A Green ◽  
Sjoerd van Ballegooy
Keyword(s):  
New Zealand ◽  
Case History ◽  
Prediction Models ◽  
Free Field ◽  
Case Histories ◽  
Cone Penetration ◽  
History Data ◽  
The Past ◽  
Surface Manifestation ◽  
The Many

Earthquakes occurring over the past decade in the Canterbury region of New Zealand have resulted in liquefaction case-history data of unprecedented quantity. This provides the profession with a unique opportunity to advance the prediction of liquefaction occurrence and consequences. Toward that end, this article presents a curated dataset containing ∼15,000 cone-penetration-test-based liquefaction case histories compiled from three earthquakes in Canterbury. The compiled, post-processed data are presented in a dense array structure, allowing researchers to easily access and analyze a wealth of information pertinent to free-field liquefaction response (i.e. triggering and surface manifestation). Research opportunities using these data include, but are not limited to, the training or testing of new and existing liquefaction-prediction models. The many methods used to obtain and process the case-history data are detailed herein, as is the structure of the compiled digital file. Finally, recommendations for analyzing the data are outlined, including nuances and limitations that users should carefully consider.

Beyond Deep Learning: An Econometric Example

2020 ◽  
Vol 28 (Supp01) ◽  
pp. 31-38 ◽  
Author(s):  
Ruofan Liao ◽  
Paravee Maneejuk ◽  
Songsak Sriboonchitta
Keyword(s):  
Neural Networks ◽  
Deep Learning ◽  
Prediction Models ◽  
Original Data ◽  
Parametric Model ◽  
Parametric Models ◽  
The Past ◽  
Currency Exchange ◽  
Currency Exchange Rate ◽  
Linear And Nonlinear

In the past, in many areas, the best prediction models were linear and nonlinear parametric models. In the last decade, in many application areas, deep learning has shown to lead to more accurate predictions than the parametric models. Deep learning-based predictions are reasonably accurate, but not perfect. How can we achieve better accuracy? To achieve this objective, we propose to combine neural networks with parametric model: namely, to train neural networks not on the original data, but on the differences between the actual data and the predictions of the parametric model. On the example of predicting currency exchange rate, we show that this idea indeed leads to more accurate predictions.

Reassessment of transient permeability measurement for tight rocks: The role of boundary and initial conditions

2021 ◽  
pp. 104173
Author(s):  
Yue Wang ◽  
Zhiguo Tian ◽  
Steffen Nolte ◽  
Alexandra Amann-Hildenbrand ◽  
Bernhard M. Krooss ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Permeability Measurement ◽  
Tight Rocks

scholarly journals Optimising the AR Engraved Structure on Light-Guide Facets for a Wide Range of Wavelengths

Optics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 25-42
Author(s):  
Ioseph Gurwich ◽  
Yakov Greenberg ◽  
Kobi Harush ◽  
Yarden Tzabari
Keyword(s):  
Theoretical Analysis ◽  
Light Guide ◽  
Spectral Band ◽  
Angular Range ◽  
The Past ◽  
Input And Output ◽  
Wide Range ◽  
The Given ◽  
Theoretical Results ◽  
Shape And Size

The present study is aimed at designing anti-reflective (AR) engraving on the input–output surfaces of a rectangular light-guide. We estimate AR efficiency, by the transmittance level in the angular range, determined by the light-guide. Using nano-engraving, we achieve a uniform high transmission over a wide range of wavelengths. In the past, we used smoothed conical pins or indentations on the faces of light-guide crystal as the engraved structure. Here, we widen the class of pins under consideration, following the physical model developed in the previous paper. We analyze the smoothed pyramidal pins with different base shapes. The possible effect of randomization of the pins parameters is also examined. The results obtained demonstrate optimized engraved structure with parameters depending on the required spectral range and facet format. The predicted level of transmittance is close to 99%, and its flatness (estimated by the standard deviation) in the required wavelengths range is 0.2%. The theoretical analysis and numerical calculations indicate that the obtained results demonstrate the best transmission (reflection) we can expect for a facet with the given shape and size for the required spectral band. The approach is equally useful for any other form and of the facet. We also discuss a simple way of comparing experimental and theoretical results for a light-guide with the designed input and output features. In this study, as well as in our previous work, we restrict ourselves to rectangular facets. We also consider the limitations on maximal transmission produced by the size and shape of the light-guide facets. The theoretical analysis is performed for an infinite structure and serves as an upper bound on the transmittance for smaller-size apertures.

scholarly journals A note on some further determinations of the dielectric constants of organic bodies and electrolytes at very low temperatures

1898 ◽  
Vol 62 (379-387) ◽  
pp. 250-266 ◽  
Keyword(s):  
Dielectric Constant ◽  
Low Temperatures ◽  
Tuning Fork ◽  
Dielectric Constants ◽  
The Past ◽  
Method Of Measurement ◽  
The Given ◽  
Past Summer

In several previous communications we have described the investigations made by us on the dielectric constants of various frozen organic bodies and electrolytes at very low temperatures. In these researches we employed a method for the measurement of the dielectric constant which consisted in charging and discharging a condenser, having the given body as dielectric, through a galvanometer 120 times in a second by means of a tuning-fork interrupter. During the past summer we have repeated some of these determinations and used a different method of measurement and a rather higher frequency. In the experiments here described we have adopted Nernst’s method for the measurement of dielectric constants, using for this purpose the apparatus as arranged by Dr. Nernst which belongs to the Davy-Faraday Laboratory.

Development of Advanced CNC Interpolation Algorithm With Consideration of Command and Dynamic Errors

2015 ◽  
Author(s):  
Meng-Shiun Tsai ◽  
Ying-Che Huang
Keyword(s):  
The Other ◽  
Contour Error ◽  
Interpolation Algorithm ◽  
Interpolation Scheme ◽  
Error Equation ◽  
The Past ◽  
Cnc Interpolation ◽  
Dynamic Errors ◽  
Simulation Results ◽  
The Given

In this paper, an integrated acceleration/deceleration with dynamics interpolation scheme is proposed to confine the maximum contour error at the junction of linear junction. The dynamic contour error equation is derived analytically and then it is utilized for the interpolation design. Based on the derived formulations which could predict the command and dynamic errors, the advanced interpolation design could adjust the connecting velocity of the two blocks to confine the overall contour errors under the given tolerance. Simulation results validate the proposed algorithm can achieve higher accurate trajectory as compared to the other interpolation algorithm proposed in the past.

scholarly journals Evaluating Financial Performance of Saudi Listed Firms: Using Statistical Failure Prediction Models

2019 ◽  
Vol 2 (1) ◽  
pp. 1-18
Author(s):  
Deena Saleh Merza Radhi ◽  
Adel Sarea
Keyword(s):  
Financial Performance ◽  
Prediction Models ◽  
Stock Exchange ◽  
Failure Prediction ◽  
Financial Decisions ◽  
Listed Firms ◽  
Industrial Companies ◽  
Statistical Relationships ◽  
The Given ◽  
Altman Model

The study aims to compare the classification power of three statistical failure prediction models for evaluating financial performance of Saudi Listed Firms. The study sample consisted of 122 listed industrial companies in the Saudi Stock Exchange for the period from 2014 to 2016. Altman model 1968, Kida model and Zmijewski are used as examples of statistical failure prediction models to evaluate the classification power of the given models to assess the financial performance of firms listed on Saudi Stock Exchange. The results showed that Zmijewski model was more powerful in predicting the financial performance of Saudi listed firms than Altman model (1986) and Kida model. The results showed that there are a statistical relationships between some ratios included in the three models and the financal performance of industrial companies, which was measured by EPS. The study recommended users of financial statements of Saudi listed companies to use Zmijewski ?model, which performs well in evaluating their finacial position to be used when making the ?financial decisions.

Hemostatic and thrombotic disorders in the pediatric patient

Blood ◽  
2021 ◽  
Author(s):  
Sarah H. O'Brien ◽  
Ayesha Zia
Keyword(s):  
Venous Thromboembolism ◽  
Prediction Models ◽  
Oral Anticoagulants ◽  
Direct Oral Anticoagulants ◽  
Hospital Setting ◽  
Von Willebrand Disease ◽  
Assessment Tools ◽  
Excessive Bleeding ◽  
The Past ◽  
New Treatment

This review focuses on significant advances in the field of pediatric hemostasis and thrombosis, with a focus on published studies within the past decade. The evaluation and management of patients with excessive bleeding remain a cornerstone of consultative hematology. We will describe the development of validated bleeding assessment tools relevant to pediatric practice, laboratory advances in the evaluation of von Willebrand Disease, and a shift in clinical practice regarding the interpretation of normal coagulation studies in patients with significant bleeding phenotypes. There have also been critical advances in the management of hemostatic disorders. This review highlights new treatment paradigms in hemophilia and the rise of multidisciplinary medical homes for women living with bleeding disorders. Given the continued increase in the incidence of thrombosis, particularly in the hospital setting, a full call to arms against pediatric venous thromboembolism is now essential. This review will describe recently completed clinical trials of direct oral anticoagulants in children and adolescents and ongoing work to elucidate the appropriate duration of therapy for children with provoked thrombosis. Recent work regarding the prevention of pediatric venous thromboembolism is highlighted, including studies of thromboprophylaxis and the development of risk-prediction models for hospital-acquired thrombosis. Finally, we review advances in our understanding of post-thrombotic sequelae and the need for continued refinement of our evaluation tools. Despite the significant advances in pediatric hemostasis and thrombosis over the past decade, many unanswered questions remain for the next generation of investigators.

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