241 research outputs found
Engineering characteristics of Egyptian limestone
Purpose. Study of physical properties such as porosity, density and mechanical properties such as compressive strength and tensile strength of Egyptian limestone based on experimental investigations.
Methods. In this paper using physical and mechanical properties to evaluate the Egyptian limestone according to the relationship between their properties especially the degree of water saturation. Samples were obtained from six different locations (Helwan, Minia, Assuit, Qena, Sohag, and Aswan).
Findings. The strong correlation between porosity and density, and good correlations between uniaxial strength and tensile strength. Carried out results indicated that, small porosity results in greater rock strength and vice versa.
Originality. Applying the fitting curve technique to check the best correlation between the different property of limestone to identify the best relationship to apply the prediction to find the limestone property in other location as regards applying conditions.
Practical implications. Results carried out that the strong correlation between porosity and density, and good correlations between uniaxial strength and tensile strength as summarize in the outcome of data interpretation. Highest quality stones, in terms of their hydric behavior and mechanical properties, are the index for the suitability of using limestone.Мета. Вивчення фізичних та механічних властивостей вапняку родовищ Єгипту на основі експериментальних досліджень.
Методика. Зразки вапняку відбирались з родовищ шести різних провінцій (Helwan, Minia, Assuit, Qena, Sohag, Aswan). Зразки кернів були підготовлені з використанням бурильного станка відповідно до критеріїв стандарту ISRM. Підготовка до випробування зразків керна проводилася перпендикулярно площинам нашарування. Відповідні властивості для виробництва заповнювача були перевірені з точки зору вмісту води, щільності, стійкості до стирання та стійкості до стирання в кінцевому підсумку на вапняковій ділянці, який більше підходить для виготовлення бетону і асфальту. Фізичні властивості (щільність та пористість) і механічні властивості (міцність на стиск, міцність на розрив і коефіцієнт динамічного дроблення) були досліджені за стандартними методиками для дев’яти зразків вапняку кожної з шести провінцій.
Результати. Для вапняку родовищ Єгипту експериментально виявлено високу кореляцію між пористістю та щільністю, а також хороші кореляції між міцністю на одновісний стиск і міцністю на розрив, що характеризує інженерні вимоги до його використання у цивільному та промисловому будівництві. Проведені результати показали, що низька пористість призводить до більшої міцності порід і навпаки.
Наукова новизна. Полягає у використанні техніки підгонки кривої для перевірки найкращої кореляції між різними властивостями вапняку при встановленні найкращого відношення, застосовуючи цей прогноз для вивчення властивостей вапняку в іншому місці.
Практична значимість. Отримані показники фізичних та механічних характеристик вапняку є корисними для визначення можливої області його застосування в цивільному та промисловому будівництві, тощо.Цель. Изучение физических и механических свойств известняка месторождений Египта на основе экспериментальных исследований.
Методика. Образцы известняка отбирались с месторождений шести различных провинций (Helwan, Minia, Assuit, Qena, Sohag, Aswan). Образцы кернов были подготовлены с использованием бурильного станка согласно критериям стандарта ISRM. Подготовка к испытанию образцов керна проводилась перпендикулярно плоскостям напластований. Подходящие свойства для производства заполнителя были проверены с точки зрения содержания воды, плотности, устойчивости к истиранию и стойкости к истиранию в конечном итоге на известняковом участке, который больше подходит для изготовления бетона и асфальта. Физические свойства (плотность и пористость) и механические свойства (прочность на сжатие, прочность на разрыв и коэффициент динамического дробления) были исследованы по стандартным методикам для девяти образцов известняка каждой из шести провинций.
Результаты. Для известняка месторождений Египта экспериментально обнаружена высокая корреляция между пористостью и плотностью, а также хорошие корреляции между прочностью на одноосное сжатие и прочностью на разрыв, характеризующие инженерные требования к его использованию в гражданском и промышленном строительстве. Проведенные результаты показали, что низкая пористость приводит к большей прочности пород и наоборот.
Научная новизна. Заключается в использовании техники подгонки кривой для проверки наилучшей корреляции между различными свойствами известняка при установлении наилучшего отношения, применяя этот прогноз для определения свойств известняка в другом месте.
Практическая значимость. Полученные показатели физических и механических характеристик известняка являются полезными для определения возможной области его применения в гражданском и промышленном строительстве и т.д.This research was partially supported by Mining and Petroleum Engineering Department, Faculty of Engineering Al-Azhar University, Egypt, that provided machines to finish the research
The Burr XII-Burr XII Distribution: Mathematical Properties and Characterizations
We introduce a new continuous distribution called the Burr XII-Burr XII distribution. Some of its properties are derived. The method of maximum likelihood is used to estimate the unknown parameters. An application is provided with details to illustrate the importance of the new. The new model provides adequate fits as compared to other related models with smallest values for A-IC, B-IC, CA-IC and HQ-IC. Characterization results are presented based on two truncated moments, hazard function as well as based on the conditional expectation
The Transmuted Weibull-Pareto Distribution
A new generalization of the Weibull-Pareto distribution called the transmuted Weibull-Pareto distribution is proposed and studied. Various mathematical properties of this distribution including ordinary and incomplete moments, quantile and generating functions, Bonferroni and Lorenz curves and order statistics are derived. The method of maximum likelihood is used for estimating the model parameters. The flexibility of the new lifetime model is illustrated by means of an application to a real data set
Comparison Between Different Algorithms for Maximum PPT in Photovoltaic Systems and its Implementation on Microcontroller
This paper presents the practical implementation of fuzzy logic control algorithm for maximum power point tracking (MPPT) in photovoltaic (PV) systems. A prototyping PV system is implemented with a boost DC-DC converter using Microchip® PIC18F452 microcontroller to execute the MPPT algorithms. The common algorithms like perturbation and observation (P&O) and incremental conductance (IncCon.) as well as the proposed fuzzy logic control algorithm are implemented and tested under different conditions, and the test results are analyzed and compared. The results show that the proposed fuzzy logic control algorithm can give better performance than perturbation and observation and incremental conductance algorithms. Keywords: Photovoltaic, Maximum power point tracking, Fuzzy logic control, Microcontrollers
The Transmuted Exponentiated Additive Weibull Distribution: Properties and Applications
A new generalization of the transmuted additive Weibull distribution is proposed by using the quadratic rank transmutation map, the so-called transmuted exponentiated additive Weibull distribution. It retains the characteristics of a good model. It is more flexible, being able to analyze more complex data; it includes twenty-seven sub-models as special cases and it is interpretable. Several mathematical properties of the new distribution as closed forms for ordinary and incomplete moments, quantiles, and moment generating function are presented, as well as the MLEs. The usefulness of the model is illustrated by using two real data sets
Traumatic cerebrospinal fluid leakage following septorhinoplasty
Septoplasty/septorhinoplasty is a common ear, nose and throat procedure offered for those patients with deviated septum who are suffering from nasal obstruction and functional or cosmetic problems. Although it is a basic and simple procedure, it could lead to catastrophic complications including major skull base injuries which result in cerebrospinal fluid (CSF) leaks. We describe two different cases of traumatic CSF leaks following septoplasty/septorhinoplasty at two different sites. The first patient suffered a CSF leak following septoplasty and presented to Alexandria University Hospital. The leak was still active at presentation and identified as coming from a defect in the roof of the sphenoid sinus and was repaired surgically. The second patient presented 4 days after her cosmetic septorhinoplasty with a CSF leak and significant pneumocephalus. She was managed conservatively. Understanding the anatomical variations of the paranasal sinuses and implementing proper surgical techniques are crucial in preventing intracranial complications when performing either septoplasty or septorhinoplasty. A good quality computed tomography of the nose and paranasal sinuses is a valuable investigation to avoid major complications especially CSF leaks following either procedure
Determinants of Emerging Technology Adoption For Safety Among Construction Businesses
This study aims to identify the antecedents of emerging technology adoption in
construction businesses. The objectives of this study were to identify the determinants and
barriers to the adoption of emerging technologies in the construction industry. This study used a descriptive research design, a quantitative research method, and a stratified simple random sampling technique to select contractors registered with the Construction Industry Development Board (CIDB) in the eastern region of Malaysia. Out of the 75 copies of questionnaire distributed to the contractors, only 24 completed and usable responses were received, yielding a response rate of 32 %. Inferential analysis and relative importance index were used to achieve the research objectives. Regarding the first objective, the findings from this research showed that project characteristics would influence the adoption of emerging technology for construction safety. The social-related factor is next to it. The other factors are environmental, technological, and organizational factors. Finally, individual factors had the least influence on adoption. Regarding the second objective of this study, the economic factor is the most influential barrier to adopting emerging technologies for construction safety, followed by personal factors in this trend. Organizational factors and time-related factors are barriers that have the least influence on adoption
The Marshall-Olkin Generalized-G Family of Distributions with Applications
We introduce a new class of distributions called the Marshall-Olkin generalized-G family. Some of its mathematical properties including explicit expressions for the ordinary and incomplete moments, order statistics are discussed. The maximum likelihood method is used for estimating the model parameters. The importance and flexibility of the new family are illustrated by means of two applications to real data sets
The association of ideal cardiovascular health with incident type 2 diabetes mellitus: the Multi-Ethnic Study of Atherosclerosis
Levels of ideal cardiovascular health (ICH) and incident type 2 diabetes mellitus have not been examined in a multiethnic population. We assessed the total and race/ethnicity-specific incidence of diabetes based on American Heart Association (AHA) ICH components
Effect of mutation and vaccination on spread, severity, and mortality of COVID-19 disease
Coronavirus disease 2019 (COVID-19) has had different waves within the same country. The spread rate and severity showed different properties within the COVID-19 different waves. The present work aims to compare the spread and the severity of the different waves using the available data of confirmed COVID-19 cases and death cases. Real-data sets collected from the Johns Hopkins University Center for Systems Science were used to perform a comparative study between COVID-19 different waves in 12 countries with the highest total performed tests for severe acute respiratory syndrome coronavirus 2 detection in the world (Italy, Brazil, Japan, Germany, Spain, India, USA, UAE, Poland, Colombia, Turkey, and Switzerland). The total number of confirmed cases and death cases in different waves of COVID-19 were compared to that of the previous one for equivalent periods. The total number of death cases in each wave was presented as a percentage of the total number of confirmed cases for the same periods. In all the selected 12 countries, Wave 2 had a much higher number of confirmed cases than that in Wave 1. However, the death cases increase was not comparable with that of the confirmed cases to the extent that some countries had lower death cases than in Wave 1, UAE, and Spain. The death cases as a percentage of the total number of confirmed cases in Wave 1 were much higher than that in Wave 2. Some countries have had Waves 3 and 4. Waves 3 and 4 have had lower confirmed cases than Wave 2, however, the death cases were variable in different countries. The death cases in Waves 3 and 4 were similar to or higher than Wave 2 in most countries. Wave 2 of COVID-19 had a much higher spread rate but much lower severity resulting in a lower death rate in Wave 2 compared with that of the first wave. Waves 3 and 4 have had lower confirmed cases than Wave 2; that could be due to the presence of appropriate treatment and vaccination. However, that was not reflected in the death cases, which were similar to or higher than Wave 2 in most countries. Further studies are needed to explain these findings
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