Rheology of hybrid matrices composed of cement and alkali-activated supplementary cementitious materials

Face aux préoccupations environnementales liées à la production du ciment Portland, la recherche d’alternatives pour une construction plus durable s’avère une nécessité. En effet, la production du ciment est responsable de l’augmentation du potentiel de réchauffement global (PRG), ce qui remet en question sa grande utilisation de point de vue environnemental. Dans cette perspective, ce projet de doctorat s’inscrit dans l’optique de la réduction de l’impact environnemental des matériaux de construction, notamment les bétons fluides à rhéologie adaptée. Les ajouts cimentaires activés se présentent comme l’une des alternatives intéressantes pouvant réduire l’impact environnemental de la construction. Cependant, l’introduction de ces matériaux dans le secteur de construction confronte des difficultés de compréhension de leurs mécanismes de prise et de durcissement. Ainsi, l’objectif principal de cette thèse est d’étudier l’impact de l’activateur alcalin sur le comportement rhéologique et les mécanismes de prise des cendres volantes et de poudre de verre activées ainsi que des matrices hybrides composées de ciment et d’ajouts cimentaires activés. Plus spécifiquement, cette étude vise à améliorer les performances rhéologiques et les caractéristiques viscoélastiques de ces matrices afin de les incorporer dans la matrice des bétons fluides, notamment le béton autoplaçant. Le couplage des mesures rhéologiques avec la spectroscopie infrarouge à transformée de Fourier et la microstructure permet de comprendre les différents mécanismes régissant le comportement à l’état frais des matrices étudiées. Les résultats obtenus ont permis d’identifier les concentrations optimales de l’activateur alcalin pour obtenir les meilleures performances rhéologiques, tout en prenant en considération les performances à l’état durci requises. La méthodologie utilisée dans cette étude a permis également de lier les performances rhéologiques au processus de géopolymérisation afin d’établir une meilleure compréhension de l’état frais de ces matériaux. Finalement, l’incorporation des pâtes optimisées dans la matrice d’un béton autoplaçant a été également évaluée. Le béton autoplaçant à base de matrice hybride a montré des performances rhéologiques et mécaniques prometteuses, ainsi qu’un potentiel de réchauffement global inférieur à celui du béton autoplaçant conventionnel. Ces résultats montrent que l’utilisation de ce nouveau type de béton autoplaçant propose une solution intéressante de point de vue environnemental, tout en maintenant les performances rhéologiques et mécaniques requises.Abstract : With the increase of the environmental concerns related to the production of Portland cement, the search for alternatives to achieve sustainable and rational construction is becoming a necessity. Indeed, the production of cement is responsible for the increase in global warming potential (GWP), which questions its widespread use from an environmental point of view. In this perspective, this study aims at reducing the environmental impact of building materials, in particular self-consolidating concrete (SCC). Geopolymers are one of the interesting alternatives that can reduce the environmental impact of construction. However, the incorporation of these materials in the construction markets faces difficulties as long as the understanding of their setting and hardening mechanisms is still a hot topic. The main objective of this thesis is to evaluate the impact of alkaline activator on the setting mechanisms and rheological behaviour of alkali-activated fly ash, alkali-activated glass powders, and hybrid matrices composed of cement and geopolymers. This study aims to assess the rheological properties and viscoelastic characteristics of these matrices and evaluate the feasibility of incorporating them to design SCC. Coupling the rheological properties with other measures, including Fourier-transform infrared spectroscopy and microstructure, makes it possible to define different mechanisms governing the fresh state of the investigated matrices. The obtained results allowed to identify the optimal concentrations of the alkaline activator to achieve the required rheological properties and mechanical performance. In addition, the methodology used in this study allowed to correlate the rheological properties to the geopolymerization process. This allowed better understanding of the fresh state of these materials. Finally, the incorporation of the optimized pastes into the matrix of SCC was also evaluated. Self-consolidating concrete based on hybrid matrix has shown promising rheological and mechanical performances, as well as a lower global warming potential than conventional SCC proportioned with cementitious materials. These results proved that the use of hybrid SCC offers an interesting solution from an environmental point of view, while achieving the required rheological and mechanical performances

Peroxisome Proliferator Activator Receptor (PPAR)- γ

Hepatoprotective potential of peroxisome proliferator activator receptor (PPAR)-α and -γ agonists, fenofibrate (FEN), and pioglitazone (PIO), respectively, against cyclophosphamide (CP)-induced toxicity has been investigated in rat. FEN and PIO (150 and 10 mg/kg/day, resp.) were given orally for 4 weeks. In separate groups, CP (150 mg/kg, i.p.) was injected as a single dose 5 days before the end of experiment, with or without either PPAR agonist. CP induced hepatotoxicity, as it caused histopathological alterations, with increased serum alanine and aspartate transaminases, total bilirubin, albumin, alkaline phosphatase and lactate dehydrogenase. CP caused hepatic oxidative stress, indicated by decrease in tissue reduced glutathione, with increase in malondialdehyde and nitric oxide levels. CP also caused decrease in hepatic antioxidant enzyme levels, including catalase, superoxide dismutase, glutathione peroxidase, and glutathione S-transferase. Furthermore, CP increased serum and hepatic levels of the inflammatory marker tumor necrosis factor (TNF)-α, evaluated using ELISA. Preadministration of PIO, but not FEN, prior to CP challenge improved hepatic function and histology, and significantly reversed oxidative and inflammatory parameters. In conclusion, activation of PPAR-γ, but not PPAR-α, conferred protection against CP-induced hepatotoxicity, via activation of antioxidant and anti-inflammatory mechanisms, and may serve as supplement during CP chemotherapy

Integrated approach for pipe failure prediction and condition scoring in water infrastructure systems

With an increasingly aging water infrastructure, decision makers are directing their attention to better ways to model and predict asset failure. Failure modeling is a discipline that addresses complex deterioration processes to better inform asset management practices. These deterioration processes and contributing factors have been addressed using a variety of models. One statistical model that has been explored in this thesis is the logistic regression model. The proposed approach consisted of developing a logistic regression model to estimate pipe-level failure probabilities in a flexible time interval. The approach further used the probabilities to estimate a Mean Time to Failure and assign pipe condition scores according to a methodology suggested by Opila and Attoh-Okine [1]. This thesis contributes with a practical and systematic methodology to capitalize on failure records and generate actionable failure probabilities and condition scores to integrate in asset prioritization strategies.Civil, Architectural, and Environmental Engineerin

The Relationship Between The University And Industrial Institutions And Its Impact On Scientific Research In Syria

The objective of this study was to assess the assessment of the teachers of The aim of this study was to assess the relationship between the university and the economic and social development institutions and their impact on scientific research in Syria. It is worth mentioning the strategy adopted by the university on the one hand and the developmental institutions on the other, and the evaluation of the relationship between them for the service of scientific research and therefore development in Syria. We used the descriptive analytical method, and relied on the questionnaire to find out the opinions of the respondents, by drawing a random sample of 356 teaching staff members in the Syrian universities and 374 public and private industrial institutions. And then unload the responses by statistical program SPSS.23, And data analysis by statistical methods, and draw conclusions, the most important of which are: - Syrian university procedures do not serve the scientific research process. - The procedures of industrial establishments do not serve the scientific research process. - The relationship between the university and industrial institutions does not serve the scientific research process. هدفت هذه الدراسة إلى تقييم العلاقة بين الجامعة و المؤسسات الصناعية الاقتصادية و الاجتماعية وانعكاسها على البحث العلمي في سورية . و ذلك من خلال الاطلاع على الاجراءات التي تنتهجها  الجامعة من جهة  والمؤسسات الصناعية من جهة أخرى ، و تقييم العلاقة بينهما لخدمة البحث العلمي و بالتالي التنمية في سورية. استخدمنا في هذا البحث المنهج الوصفي التحليلي، و اعتمدنا على الاستبانة لمعرفة آراء المبحوثين ، من خلال سحب عينة عشوائية تضمنت 356 عضو هيئة تدريسية في الجامعات السورية ، و 374 مؤسسة صناعية عامة وخاصة  . ثم تفريغ الاستجابات بواسطة البرنامج الاحصائي SPSS.23 ، و تحليل البيانات بواسطة الأساليب الاحصائية ، و استخلاص النتائج التي كان من أهمها ما يلي : - اجراءات الجامعة السورية لا تخدم عملية البحث العلمي. - اجراءات المؤسسات الصناعية لا تخدم عملية البحث العلمي . - العلاقة بين الجامعة و المؤسسات الصناعية لا تخدم عملية البحث العلمي .

Study The Of The Effect Of Non-Performing Loans On The Efficiency Of Banking Profits (An Applied Study On Traditional Syrian Private Banks)

This research seeks to highlight the impact of non-performing loans on the efficiency of profits (alternative and standard), as non-performing loans became the focus of all banks because of their impact on financial performance. The study was conducted on traditional private banks in the Syrian Arab Republic during the period from 2005 to 2016. In the first stage, the efficiency of alternative and standard profits was estimated using the Stochastic Frontier Analysis (SFA) method. In the second stage, the Tobit Regression Model regression analysis is used to detect the effect of non-performing loans on profit efficiency, where the most important results: -  There were significant statistical differences in Profit efficiency of alternative and standard between traditional private banks. -  Negative impact of non-performing loans on profit efficiency (alternative and standard). -  The use of the Stochastic Frontier Analysis (SFA) method in estimating the efficiency of alternative and standard better than the use the Least Square Method, which aims to separate the components of the error from the case of inefficiency. -  The efficiency of alternative profit is higher than the profit efficiency on average for the study period and according to averages for each year. يسعى هذا البحث إلى إبراز أثر القروض المتعثرة على كفاءة الأرباح (البديلة والمعيارية) حيث أصبحت القروض المتعثرة محل اهتمام كل المصارف وذلك لما لها من تأثير على الأداء المالي، وتم إجراء الدراسة على المصارف الخاصة التقليدية في الجمهورية العربية السورية خلال الفترة من عام 2005 لغاية 2016  وذلك باتباع منهج من مرحلتين ، في المرحلة الأولى تم تقدير كفاءة الأرباح البديلة والمعيارية من خلال استخدام طريقة حد التكلفة العشوائيSFA )Stochastic Frontier Analysis  )،  أما في المرحلة الثانية تم استخدام تحليل انحدار Tobit Regression Model  للكشف عن أثر القروض المتعثرة على كفاءة الأرباح،  حيث كانت أهم النتائج: v   وجود فروق ذات دلالة إحصائية في كفاءة الأرباح البديلة والمعيارية بين المصارف الخاصة التقليدية. v    وجد أثر سلبي للقروض المتعثرة على كفاءة الأرباح (البديلة والمعيارية). v   إن استخدام طريقة حد التكلفة العشوائي في تقدير كفاءة الأرباح البديلة والمعيارية أفضل من استخدام طريقة المربعات الصغرى، حيث تهدف إلى فصل مكونات الخطأ عن حالة نقص الكفاءة. v   أن كفاءة الربح البديل أعلى من كفاءة الربح المعياري بالمتوسط لفترة الدراسة وأيضاً حسب المتوسطات لكل سنة

أثر برنامج تدريبي باستخدام التلقين لتنمية اللغة الاستقبالية "المفاهيم البيئية" لدى عينة من الأطفال المصابين باضطراب طيف التوحد

أثر برنامج تدريبي باستخدام التلقين لتنمية اللغة الاستقبالية "المفاهيم البيئية" لدى عينة من الأطفال المصابين باضطراب طيف التوح

The influence of nano-additives in strengthening mechanical performance of 3D printed multi-binder geopolymer composites

The weak mechanical properties the 3D printed parts can limit the competence of this technology when compared to conventionally cast-in-mold cementitious composites structures. However, experimental results in this study showed that the incorporation of nano additives could improve the mechanical property of printed structures. Six geopolymeric mixtures were designed and tested for their flow-ability, shape stability, buildability and mechanical performance. Different dosage of nano graphite platelets (NGPs) ranging from 0.1% to 1%, by the weight of geopolymer, were incorporated to the best performing geopolymer. The 3D printed geopolymer with 1% of NGPs increased the flexural strength by 89% and 46% compared to the same 3D printed and casted geopolymer without any NGPs, respectively. The same increase for compressive strength was 28% and 12%. Moreover, the geopolymer mix containing 1% of NGPs demonstrated the best shape retention and buildability

Rheology of hybrid matrices composed of cement and geopolymer

Face aux préoccupations environnementales liées à la production du ciment Portland, la recherche d’alternatives pour une construction plus durable s’avère une nécessité. En effet, la production du ciment est responsable de l’augmentation du potentiel de réchauffement global (PRG), ce qui remet en question sa grande utilisation de point de vue environnemental. Dans cette perspective, ce projet de doctorat s’inscrit dans l’optique de la réduction de l’impact environnemental des matériaux de construction, notamment les bétons fluides à rhéologie adaptée. Les géopolymères se présentent comme l’une des alternatives intéressantes pouvant réduire l’impact environnemental de la construction. Cependant, l’introduction de ces matériaux dans le secteur de construction confronte des difficultés de compréhension de leurs mécanismes de prise et de durcissement.Ainsi, l’objectif principal de cette thèse est d’étudier l’impact de l’activateur alcalin sur le comportement rhéologique et les mécanismes de prise des géopolymères à base de cendres volantes et de poudre de verre activées ainsi que des matrices hybrides composées de ciment et de géopolymères. Plus spécifiquement, cette étude vise à améliorer les performances rhéologiques et les caractéristiques viscoélastiques de ces matrices afin de les incorporer dans la matrice des bétons fluides, notamment le béton autoplaçant. Le couplage des mesures rhéologiques avec la spectroscopie infrarouge à transformée de Fourier et la microstructure permet de comprendre les différents mécanismes régissant le comportement à l’état frais des matrices étudiées. Les résultats obtenus ont permis d’identifier les concentrations optimales de l’activateur alcalin pour obtenir les meilleures performances rhéologiques, tout en prenant en considération les performances à l’état durci requises. La méthodologie utilisée dans cette étude a permis également de lier les performances rhéologiques au processus de géopolymérisation afin d’établir une meilleure compréhension de l’état frais de ces matériaux. Finalement, l’incorporation des pâtes optimisées dans la matrice d’un béton autoplaçant a été également évaluée. Le béton autoplaçant à base de matrice hybride a montré des performances rhéologiques et mécaniques prometteuses, ainsi qu’un potentiel de réchauffement global inférieur à celui du béton autoplaçant conventionnel. Ces résultats montrent que l’utilisation de ce nouveau type de béton autoplaçant propose une solution intéressante de point de vue environnemental, tout en maintenant les performances rhéologiques et mécaniques requises.With the increase of the environmental concerns related to the production of Portland cement, the search for alternatives to achieve sustainable and rational construction is becoming a necessity. Indeed, the production of cement is responsible for the increase in global warming potential (GWP), which questions its widespread use from an environmental point of view. In this perspective, this study aims at reducing the environmental impact of building materials, in particular self-consolidating concrete (SCC). Geopolymers are one of the interesting alternatives that can reduce the environmental impact of construction. However, the incorporation of these materials in the construction markets faces difficulties as long as the understanding of their setting and hardening mechanisms is still a hot topic.The main objective of this thesis is to evaluate the impact of alkaline activator on the setting mechanisms and rheological behaviour of geopolymers based on fly ash, alkali-activated glass powders, and hybrid matrices composed of cement and geopolymers. This study aims to assess the rheological properties and viscoelastic characteristics of these matrices and evaluate the feasibility of incorporating them to design SCC. Coupling the rheological properties with other measures, including Fourier-transform infrared spectroscopy and microstructure, makes it possible to define different mechanisms governing the fresh state of the investigated matrices. The obtained results allowed to identify the optimal concentrations of the alkaline activator to achieve the required rheological properties and mechanical performance. In addition, the methodology used in this study allowed to correlate the rheological properties to the geopolymerization process. This allowed better understanding of the fresh state of these materials. Finally, the incorporation of the optimized pastes into the matrix of SCC was also evaluated. Self-consolidating concrete based on hybrid matrix has shown promising rheological and mechanical performances, as well as a lower global warming potential than conventional SCC proportioned with cementitious materials. These results proved that the use of hybrid SCC offers an interesting solution from an environmental point of view, while achieving the required rheological and mechanical performances

Peroxisome Proliferator Activator Receptor (PPAR)-γ Ligand, but Not PPAR-α, Ameliorates Cyclophosphamide-Induced Oxidative Stress and Inflammation in Rat Liver

Hepatoprotective potential of peroxisome proliferator activator receptor (PPAR)-α and -γ agonists, fenofibrate (FEN), and pioglitazone (PIO), respectively, against cyclophosphamide (CP)-induced toxicity has been investigated in rat. FEN and PIO (150 and 10 mg/kg/day, resp.) were given orally for 4 weeks. In separate groups, CP (150 mg/kg, i.p.) was injected as a single dose 5 days before the end of experiment, with or without either PPAR agonist. CP induced hepatotoxicity, as it caused histopathological alterations, with increased serum alanine and aspartate transaminases, total bilirubin, albumin, alkaline phosphatase and lactate dehydrogenase. CP caused hepatic oxidative stress, indicated by decrease in tissue reduced glutathione, with increase in malondialdehyde and nitric oxide levels. CP also caused decrease in hepatic antioxidant enzyme levels, including catalase, superoxide dismutase, glutathione peroxidase, and glutathione S-transferase. Furthermore, CP increased serum and hepatic levels of the inflammatory marker tumor necrosis factor (TNF)-α, evaluated using ELISA. Preadministration of PIO, but not FEN, prior to CP challenge improved hepatic function and histology, and significantly reversed oxidative and inflammatory parameters. In conclusion, activation of PPAR-γ, but not PPAR-α, conferred protection against CP-induced hepatotoxicity, via activation of antioxidant and anti-inflammatory mechanisms, and may serve as supplement during CP chemotherapy

Personal hygiene among college students in Kuwait: A Health promotion perspective

Background: Most infectious diseases result from a lack of knowledge and poor personal hygiene. Hand hygiene, in particular, is one of the most common means by which pathogens are transmitted. The aim of this study was to determine college student's knowledge and awareness of personal hygiene in Kuwait. Materials and Methods: A multi-dimensional health assessment approach was followed using a self-administered questionnaire that was distributed among students of two colleges (the College of Nursing and the College of Health Sciences). Item analysis was conducted on 33 items of the questionnaire and measure five types of hygiene practices: hand hygiene, body hygiene, special hair application, oral care, and clothes hygiene. The data collected in the questionnaires and results were analyzed using statistical software SPSS version 23. Statistical analysis was performed using ANOVA and Student's t-test. Internal consistency, reliability was good, with an overall Cronbach's Alpha value of 0.749. Results: Most respondents were female with 64%, while 80% of the college students were in the age of <20-year-old. Twelve items were underhand hygiene practices, and four items under body hygiene. Nine items were under oral care; three, items were under hair application. Three were under clothes hygiene. Conclusions: This study showed that female students had a better knowledge and were more hygienic in hand hygiene, hair application, and body hygiene whereas, male students showed a better oral hygiene practice. Nevertheless, this study shows that the hygiene questionnaire is an acceptable and reliable measure of awareness and practice among college students