259 research outputs found
Structural study using <sup>29</sup> Si and <sup>27</sup> Al Solid State MAS NMR and compressive strength analysis of metakaolin-based geopolymer paste
No full textGeopolymers are hardened aluminosilicate gel that develop strength via the crosslinking of tetrahedral silicate and aluminate. Past Research has highlighted a wide range of mechanical properties of geopolymer synthesised from various aluminosilicate materials. This research focuses on studying the effect of variation in the percentages of metakaolin, sodium silicate and sodium hydroxide at a fixed water to solids ratio on the development of geopolymer structure and compressive strength. Kaolin was thermally treated and XRD and FTIR traced the changes in crystalline Kaolin and its transformation into a more disordered structure of metakaolin. Characterisation techniques were used for the study of geopolymer produced. FTIR analysis illustrated the changes in the characteristic bands of metakaolin after being activated with sodium silicate and sodium hydroxide to form geopolymer. The 27Al and 29Si Solid State MAS NMR spectra confirmed the formation of polymerised tetrahedral silicate interconnected to tetrahedral aluminate in the form of Q4(4Al) and Q4(3Al) which are responsible for the attained compressive strength of geopolymer. The produced geopolymers exhibited high early compressive strength and high 28-day compressive strength in the range of 30–81 MPa. This promotes the use of geopolymers as a replacement to Ordinary Portland cement especially in targeted construction applications.This study is part of Ph.D of author Heba Fouad and the PhD was a fellowship granted by Yousef Jameel Foundation. Also, Heba Fouad also would like to show her gratitude to Dr. Abdel Hamid Emwas and Dr. Mariusz Jaremko for conducting Solid State MAS NMR samples in KAUST Core lab
[Challenges and steps forward for public services reforms in Libya]
No full text[authors: Mohamed Elmagbri - lead author, Heba Al-Sheikh, Lamis Ben Aiyad, Rima Hamidan]Text arabischArabisc
Challenges and steps forward for public services reforms in Libya
No full textauthors: Mohamed Elmagbri - lead author, Heba Al-Sheikh, Lamis Ben Aiyad, Rima Hamida
Metakaolin-based Geopolymer Concrete; Synthesis, Development and Characterization
No full textGeopolymers are rendered as an essential sustainable replacement to the widely used Ordinary Portland Cement (OPC) which causes immense carbon dioxide emissions, hence a detrimental impact on society’s health and the environment. Geopolymers are three-dimensional networks of polymerized tetrahedral silicate and aluminate in the form of Q4(4Al), Q4(3Al) and Q4(2Al) which act as the principal binding phase in concrete. Past research has reported the synthesis of geopolymers from different aluminosilicates precursors, their characterization, and their wide range properties. However, previous studies still have not properly investigated effective range of synthesis ratios for a particular source material, optimum curing regimes, short- and long-term properties of paste, mortar and concrete, and finally possible construction applications. This research has focused on the study of kaolin calcination for proper geopolymerization of metakaolin using sodium hydroxide and sodium silicate, development of a guidance design chart that shows range of feasible mixes and the design of geopolymer concrete and the study of its mechanical properties. The design chart is the main contribution of this research and aims at providing a well-established baseline for the synthesis of metakaolin geopolymer.
In the first stage, the used kaolin was properly characterized before and after calcination using different spectroscopic techniques including XRD, TGA, FTIR and 27Al and 29Si solid state MAS NMR. It was found that calcination at 750°C for 7 hours results in effective breakage of the hydroxyl group from the kaolin sheets. In the second stage, geopolymer paste was produced at different mixing percentages. A total of 52 mixes were designed and studied. Based on the quantitative analysis of compressive strength and qualitative analysis of setting time and workability, the feasible range for producing a workable geopolymer mix of reasonable strength was highlighted. The 28-day compressive strength of geopolymer paste ranged between 30 to 94 MPa and the workability varied from being very stiff to highly workable depending on the synthesis ratios. The research points out a concern, which was not previously addressed in the literature, the high temperature of geopolymer paste at some synthesis percentages. This requires further investigation for practical handling of the material in construction applications. The stress-strain curves of geopolymer paste showed a brittle behavior and the lowest and highest tangent modulus of elasticity at 7-day was recorded to be 4.4 and 7.3 GPa respectively. 29Si and 27Al MAS NMR analysis detected the presence of tetrahedrally coordinated silicate and aluminate crosslinked in form of Q4(4Al) and Q4(3Al) and thus confirmed the formation of geopolymer gel network. Finally, six geopolymer concrete mixes were developed at specific mixing ratios depending on the developed guidance chart and their mechanical properties were investigated. The studied fresh and mechanical properties include workability, temperature, compressive strength, flexural strength, drying shrinkage, rapid chloride penetration test in addition to chemical resistance in acid (10% hydrochloric acid) and sulfates (saturated magnesium sulfate solution) for a total duration of 4 months.
It was concluded that calcined kaolin can be alkaline activated to produce geopolymer concrete of comparable or even advanced mechanical properties at ambient curing temperature. Calcination of kaolin is a primary step that needs to be effectively conducted at the right temperature, duration and rate prior to geopolymerization. The crosslinking of silicate and aluminate species to form geopolymer network depends on the synthesis materials percentages. Research conducted contributed to demonstrating the feasible range of metakaolin, sodium silicate and sodium hydroxide to synthesize geopolymer and clarifying the relationship between the percentages of three component system and the compressive strength development as a first step towards reaching a structure-directed synthesis. Geopolymer concrete exhibited superior mechanical properties and can be used in various construction applications based on the obtained properties
Bridging the Gap: Analyzing Volunteerism Barriers to the International Humanitarian NGOs in Egypt
No full textIn Egypt, volunteerism, within international humanitarian non-governmental organizations (NGOs), functions in distinctive characteristics influenced by, among other things, cultural, educational, and economic factors. NGOs face challenges and obstacles in attracting motivated volunteers, engaging and training volunteers, as well as managing the staff-volunteers relationship, and implementing adequate human resources (HR) policies and strategies. In this context, this thesis seeks to bridge the knowledge gap of volunteerism challenges in Egypt, delving deep into understanding the barriers existing within the international humanitarian NGOs that directly and indirectly influence its volunteer engagement levels. The thesis also aims to understand the successful implementation of policies and procedures that encourage and facilitate effective volunteering engagement. In order to fulfill these objectives, semi-structured interviews were conducted with volunteers and employees of the Egyptian Red Crescent, the Catholic Relief Services, and the Cares Egypt international humanitarian NGOs. The findings of the study indicate that while the Egyptian ecosystem and NGOs\u27 policies and procedures may affect individuals in diverse ways, a professional volunteer management approach that addresses factors such as volunteers\u27 motivational aspects, effective relationships with direct supervisors, and proper recognition for the workload and volunteers’ availability can directly and positively impact volunteering engagement when implemented effectively. Therefore, it is essential to advocate for a professional volunteer management approach that ensures effective volunteer selection and onboarding, effective implementation of supervision techniques and volunteer feedback and communication, implementation of a volunteer recognition program that emphasizes high performance, identification of volunteers\u27 strengths and interests to provide opportunities for skill development and ensuring volunteer flexibility and work-life balance. Ultimately, the implementation of such management policies and strategies can provide volunteers with a pleasant experience while ensuring the effective operation of NGOs, leading to constant and effective volunteer engagement
The sound of egyptian television
No full textThis audio documentary is to clarify how Egyptian soundtracks are the key success that influences the audience’s feelings in a movie or series, through a journey of soundtracks in the history of the Egyptian Television. Along with the interviewees: Dr Rasha Abdalla - Assistant Professor at Ain Shams University Amr Ismail - Egyptian Composer Professor Chelsea Green - Music History Professor at the American University in Cair
Pregnancy and insulin sensitivity in relation to Exercise training (A scoping review)
No full textAbstract: This study is aimed to estimate the relation of exercise training on insulin sensitivity and pregnancy. Twenty females at the second trimester of pregnancy participated in this study. Their age was 20 to 40 years with BMI less than 35 km2. They divided into two equal group. The study group (A) performed exercise program for four weeks, 3 sessions per week. While the control group maintain their daily life activity routine. There was a significance difference in the mean value of insulin sensitivity level in group A and there was a significance difference in the mean value between groups in favoring to group (A). So, it could be concluded that exercise training is an effective method on insulin sensitivity during pregnancy.
Keywords: pregnancy, insulin senstivity, exercise training.
Title: Pregnancy and insulin sensitivity in relation to Exercise training (A scoping review)
Author: Heba Embaby, Mohamed Elbanna
International Journal of Novel Research in Healthcare and Nursing
ISSN 2394-7330
Vol. 9, Issue 3, September 2022 - December 2022
Page No: 192-198
Novelty Journals
Website: www.noveltyjournals.com
Published Date: 10-November-2022
DOI: https://doi.org/10.5281/zenodo.7310301
Paper Download Link (Source)
https://www.noveltyjournals.com/upload/paper/Pregnancy%20and%20insulin%20sensitivity-10112022-1.pdfInternational Journal of Novel Research in Healthcare and Nursing, ISSN 2394-7330, Novelty Journals, Website: www.noveltyjournals.co
Relationship between Nursing Students' Motivation to Learn and Their Competency Self-Efficacy at Secondary Technical Schools of Nursing
No full textAbstract: Motivation to learn and competency self-efficacy(CSE) are two of the most influential factors that affect nursing students academic performance and clinical success. Aim: Investigate the relationship between nursing students' motivation to learn and their competency self-efficacy. Study design: A descriptive correlational research design was utilized to conduct this study. Setting: in 6 schools (3 female- 3male) out of 19 Secondary Nursing Technical Schools in Kafr El-Shikh governorate. Subjects: included Nursing Students in the previously selected settings (n=278) (134 female and 144 male). Tools: Two tools were used to conduct this study: Motivation to learn questionnaire and Nursing competency self-efficacy scale (NCSE). Results: The finding of this study revealed that the vast majority of the studied nursing students had high level of motivation to learn and nursing students had high level of competency self-efficacy. Conclusion: There was high levels of nursing students’ motivation to learn and high levels of competency self-efficacy (CSE). A statistically significant relationship was noticed between motivation to learn and competency self-efficacy. Recommendations: Develop strategies to motivate nursing students to learn and improve their competency self-efficacy.
Keywords: Motivation to learn, Nursing competency self-efficacy, Nursing students.
Title: Relationship between Nursing Students’ Motivation to Learn and Their Competency Self-Efficacy at Secondary Technical Schools of Nursing
Author: Asmaa Gomaa El-Gaafarey Mohamed, Neamat Mohamed El-sayed, Heba Mohamed Alanwar Ashour
Title: Relationship between Nursing Students’ Motivation to Learn and Their Competency Self-Efficacy at Secondary Technical Schools of Nursing
Author: Asmaa Gomaa El-Gaafarey Mohamed, Neamat Mohamed El-sayed, Heba Mohamed Alanwar Ashour
International Journal of Novel Research in Healthcare and Nursing
ISSN 2394-7330
Vol. 10, Issue 1, January 2023 - April 2023
Page No: 22-35
Novelty Journals
Website: www.noveltyjournals.com
Published Date: 12-January-2023
DOI: https://doi.org/10.5281/zenodo.7528763
Paper Download Link (Source)
https://www.noveltyjournals.com/upload/paper/Relationship%20between%20Nursing%20Students-12012023-1.pdfInternational Journal of Novel Research in Healthcare and Nursing, ISSN 2394-7330, Novelty Journals, Website: www.noveltyjournals.co
The impact of perceived quality of after-sale services on post-purchase evaluation outcomes of passenger automobiles customers in Egypt
No full textThe purpose of this research is to asses the impact of after-sale services on post purchase evaluation outcomes of customers. Three directions of outcomes had been focused on: positive outcomes, negative outcomes, and cognitive dissonance. A survey was conducted and structural equation modelling was used to test hypothesis. The results indicate that after-sale services had a triple effect on post purchase outcomes as they enhance positive outcomes (satisfaction, loyalty, and PWOM), decrease negative outcomes (regret and NWOM) adding to that its positive impact on reducing cognitive dissonance
The impact of perceived quality of after-sale services on post-purchase evaluation outcomes of passenger automobiles customers in Egypt
No full text- …
