Mechanical properties and durability assessment of nylon fiber reinforced self-compacting concrete

[EN] The higher paste volume in Self Compacting Concrete (SCC) makes it susceptible to have a higher creep coefficient and cracking and has brittle nature. This brittle nature of concrete is unacceptable for any construction industry. The addition of fibers is one of the most prevalent methods to enhance the ductile and tensile behavior of concrete. Fibers reduce the cracking phenomena and improve the energy absorption capacity of the structure. Conversely, the addition of fibers has a negative impact on the workability of fresh concrete. In this research work, a detailed investigation of the influence of Nylon fibers (NFs) on fresh properties, durability, and mechanical properties of SCC was carried out. NFs were added into concrete mixes in a proportion of 0.5%, 1%, 1.5%, and 2% by weight of cement to achieve the research objectives. Durability assessment of modified SCC having Nylon fibers was performed using water absorption, permeability, carbonation resistance, and acid attack resistant. Mechanical tests (compressive and tensile) were conducted for modified as well as control mix. Test results indicate that the passing and filling ability decreased while segregation and bleeding resistance increased with NFs. Furthermore, test results showed a significant increase in strength up to 1.5% addition of nylon fibers and then strength decreases gradually. Durability parameters were significantly improved with the incorporation of NFs relative to the control mix. Overall, this study demonstrated the potential of using nylon fibers in self-compacting concrete with improved durability and mechanical properties.SIThe author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through group research program under grant number RGP. 1/100/42 and Taif University Researchers Supporting Project (number TURSP- 2020/276), Taif University, Taif, Saudi Arabi

Solution properties of hydrophobically modified

We tested nine hydrophobically modified polyacrylamides with molecular weights situated between 1.58 and 0.89 × 106 g/mol for enhanced oil recovery applications. Their solution properties were investigated in the distilled water, brine solution, formation water and sea water. Their critical association concentrations were determined from the relationship between their concentrations and the corresponding apparent viscosities (ηapp) at 30 °C at shear rate 6 s−1. They were between 0.4 and 0.5 g/dl. The brine solutions of 0.5 g/dl of HM-PAMs were investigated at different conditions regarding their apparent viscosities. Such conditions were mono and divalent cations, temperature ranging from 30 to 90 °C, the shear rate ranging from 6 to 30 s−1 and the aging time for 45 days. The surface and interfacial tensions for the HM-PAMs were measured for concentration range from 0.01 to 1 g/dl brine solutions at 30 °C and their emulsification efficiencies were investigated for 7 days. The discrepancy in the properties and efficiencies of the tested copolymers was discussed in the light of their chemical structure

Synthesis and characterization of high molecular weight hydrophobically modified polyacrylamide nanolatexes using novel nonionic polymerizable surfactants

In this article, nine hydrophobically modified polyacrylamides (HM-PAM) nanolatexes, were synthesized by copolymerizing the acrylamide monomer and novel polymerizable surfactants (surfmers). The reaction was carried out by inverse microemulsion copolymerization technique. The copolymerization was initiated by redox initiators composed of potassium peroxodisulphate and sodium bisulfite. The emulsion was stabilized using mixed tween 85 and span 80 as nonionic emulsifiers. The prepared HM-PAMs were classified into three groups according to the surfmers used in the copolymerization. The chemical structures of the prepared HM-PAMs were confirmed by FT-IR, 1H NMR and 13C NMR. The thermal properties were estimated with the thermal gravimetric analysis (TGA). The size and morphology of the prepared latexes were investigated by the dynamic light scattering (DLS) and the High Resolution Transmission Electron Microscope (HRTEM). Finally, the molecular weights of the prepared copolymers were determined by the GPC and the viscosity average molecular weight method. They were situated between 1.58 × 106 and 0.89 × 106

تاثيرات الجوسيبول و ابوجوسيبول و جوسيبولون علي خصوبة ذكور الفئران وحركة الحيوانات المنوية خارج الجسم

The effect of the naturally occurring polyphenolic pigment, gossypol, and some of its metabolites, apogossypol and gossypolone, on the fertility of male rats has been studied in vivo. The normal growth of the rats was significantly retarded in gossypol and gossypolone treated groups compared to either the controls or to apogossypol group. The in vivo effect of these compounds on sperm mobility was also examined. Gossypol acetic acid and gossypolone injection (5 mg/Kg body weight) decreased significantly the sperm count and sperm motility. Whereas apogossypol (5 mg/Kg body weight) showed insignificant effects on the sperm count and sperm motility. Gossypol and gossypolone decrease significantly the sperm mobility in vitro at different concentrations studied (5 up to 40 mg/ml saline). Apogossypol, only at high concentration (40 mg/ml) indicate inhibitory effect on sperm motility. Gossypol showed intermediate effect between the highly toxic compound, gossypolone, and the less toxic one, apogossypol.تمت دراسة التأثيرات - داخل الجسم الحي - التي يحدثها الجوسيبول - وهي صبغة عديدة الفينولات من النواتج الطبيعية - ومشتقاتها ابوجوسيبول وجوسيبولون على الخصوبة في ذكور الفئران ، كما درس أيضاً تأثير المركبات الثلاثة على حركة الحيوانات المنوية خارج الجسم الحي . تأخر النمو الطبيعي للفئران المعالجة بواسطة جوسيبول وجوسيبولون بفروق احصائية واضحة مقارنة بالفئران المعالجة بواسطة ابوجوسيبول أو بحيوانات المجموعة الضابطة . وقد أدى حقن الفئران بالجوسيبولون - 5ملليجرام / كيلو جرام من وزن الجسم - إلي حدوث نقص احصائي واضح لكل من عدد و حركة الحيوانات المنوية . في حين لم يظهر حقن ابوجوسيبول أي تأثير على الخصوية ، إلا أنه أظهر تأثيرا على حركة الحيوانات المنوية خارج الجسم الحي فقط عند تركيز 40 ملليجرام / ملليلتر مذيب . ويمكن اعتبار ابوجوسيبول مانع للخصوبة فقط في التركيزات المرتفعة ، وقد أظهر الجوسيبول تأثيرا متوسطاً بين الجوسيبولون - المركب عالي السمية - و ابوجوسيبول - الأقل في درجة السمية

تأثير جوسيبول وجوسيبولون وأبوجوسيبول على الليبيدات في مصل الدم والسائل المنوي في ذكور الفئران

The neutral and polar lipids of serum and seminal fluid of male rats were investigated under the effect of gossypol acetic acid, apogossypol and gossypolone. The total phospholipids and the neutral serum lipids showed positive and negative significant correlation with the duration of gossypol acetic acid treatment, respectively. At the same time, free fatty acids content significantly increased with apogossypol and gossypol acetic acid. In seminal fluids, the total lipid fraction showed insignificant variation in spite of the correlation between triglycerides and sterylester content. In control animals, triglycerides and sterylester contents showed positive and negative correlation, respectively. Only sterylester showed a negative significant correlation with the duration of apogossypol treatment. This result may be related to the negative effect of apogossypol on fertility. The effect of gossypol acetic acid, apogossypol and gossypolone on the total phospholipids constituents of male rat serum and seminal fluid were studied. Phosphatidyl inositol was significantly decreased under the effect of gossypol acetic acid and gossypolone in the serum, and negatively significant correlated with the duration of gossypol acetic acid and gossypolone treatment in the seminal fluid. The results indicate that infertility dose of gossypol and gossypolone exhibit some metabolic effect by elevation of lipolysis and perhaps depression of phospatidyl inositol biosynthesis.تمت دراسة تأثيرات خلات الجوسيبول وأبوجوسيبول وجوسيبولون على الدهون المتعادلة والدهون القطبية في مصل السم وسائل المني في ذ كور الفئران . أظهرت مجموعة الفسفوليبيدات ومجموع الليبيدإِت المتعادلة في المصل علاقة تزايدية معنوية ويقابلها علاقة تناقصية معنوية على الترتيب مع زمن المعالجة بخلات الجوسيبول في نفس الوضآ زاد معثوياً محتوى الأحماخى الدهنية الحرة تحت تاثير الجوسيبول والأبوجوسيبول . في السائل المنل ي - أظهر مجموع الليبيدات الكلية تغي!راً غير معنوي بالنخكم من وجود علاقة معنوية بين محتواها من الجلسريدات الثلاثية سأسترات الأستينيل . في المجموعة القياسية - أمكن تحديد علاقة تزايدية معنوية بين كمية الجلسريدات الثلاثية ورْمن الدراسة يقابلها علاقة تناقصية في كمية أسترات ستيريل لنفس المجموعة . فقط تحت تا اثيرات أبوجوسيبولى أظهر علامة تثاقصية بين أسترات ستيريل وزمن المعالجة . هذه النتيجة يمكن ربطها بالتأثير السلبي للأبوجوسيبول على الخصوبة . بدراسة تأثير خلات الجوسيبول وأبوجوسيبول وجوسيبولوق على مكونات الفسفوليبيدات إِلكلية في مصل لمحم وسائل المثي لشكور الفئران وجد أن فوسفاتيهديل اللإنيزيتول بالمصل انخفضت كميتها بدرجة معنوية تحت تأثير خلات جوسيبول والجوسيبولون وكانت العلاقة تناقصية معثوية بسرمجة كبيرة بين كمية فوسفاتيديل الإنيزيتول في السائل الملنوي وزمن المعالجة بخلات الجوسيبول والجوسيبولت . تشير الثتائج إلى أن الجرعات المسببة للعقنم من جوسيبول وجوسيبولون تعطي بعض الث ثيرات على الأيض من رفع لمعدل تحلل الدهون وبالتالي خفض في معدل بناء فوسفاتيديل أثيروتول

تأثير جوسيبول وأبوجوسيبول وجوسيبولون على نمط الأحماض الدهنية لأقسام الليبيدات في مصل الدم والسائل المنوي للفأر

he fatty acids pattern of the total lipid fractions of male rat serum and seminal fluids were studied under the effect of gossypol and some of its metabolites (Apogossypol and gossypolone). The applied dose of gossypol and its derivatives exhibits some metabolic effects such as significant decrease of the saturated fatty acids and a significant increase of polyunsaturated fatty acids. In the serum, eicosapentaenoic acid (C20:5) in sterylester fraction was significantly increased under the effect of apogossypol. While in the free fatty acids fraction, palmitic acid (C16:0) content was significantly decreased, meanwhile significant increase of polyunsaturated fatty acid (C22:5) with apogossypol and gossypolone treatment. Stearic acid (C18:0) was significantly decreased in the total phospholipids fraction due to the treatment with gossypol acetic acid, apogossypol and gossypolone. In the seminal fluid, also eicosapentaenoic acid (C20:5), in sterylester fraction, was significantly increased with apogossypol treatment. In triglycerides, free fatty acids and phospholipids fractions, mono-unsaturated fatty acids were significantly decreased after gossypol and gossypolone treatment. Also, linoleic acid was significantly increased in the main fractions (triglycerides) under the effect of gossypol and gossypolone. Gossypol and gossypolone which induced sterility, may have significant effect on NAD and NADP-dependent enzymes, ATPase and/or have local effect on the germinal cells. Therefore, apogossypol which did not cause sterility, has no effect on the process of spermatogenesis as well as the content of seminal monounsaturated fatty acids.دُرست أنماط الأحماض الدهنية لأقسام الليبيدات الكلية في مصل الدم وسائل منوي من ذكر الفأر وذلك تحت تأثير جوسيبول وبعض مشتقات الأيض الخاصة به (أبوجوسيبول وجوسيبولون ) . أظهرت النتائج أن الجرعة المستخدمة من جوسيبول وأبوجوسيبول وجوسيبولون تؤثر على أيض بعض مركبات مثل خفض الأحماض الدهنية المشبعة وزيادة معنوية للأحماض الدهنية عديدة الروابط الغير مشبعة . في مصل الدم زاد معنوياً حمض (ك 20 :5 ) في قسم استرالاستيرولات وذلك تحت تأثير أبوجوسيبول . وبينما نقص معنوياً حمض البالميتيك من قسم الأحماض الدهنية الحرة وظهر في نفس الوقت زيادة معنوية للحمض الدهني خماسي الروابط الغير مشبعة (ك 22 :5 ) بالمعالجة بأبوجوسيبول وجوسيبولون . وفي قسم الفسفوليبيدات الكلية انخفض معنوياً حمض إستياريك (ك 18 : 0 )نتكليجة للمعالجة بواسطة خلات الجوسيبول وجوسيبولون وأبوجوسيبول . في السائل المنوي زاد أيضاً معنوياً محتوى استرات ستيرولات من حمض (ك 20 :5 ) بالمعالجة بأبوجوسيبول . وفي أقسام الجلسريدات الثلاثية وقسم الأحماض الدهنية الحرة وأقسام الليبيدات الفسفاتية انخفض معنوياً محتواها من الأحماض الدهنية وحيدة الرابطة الغير مشبعة ، وذلك لمعالجتها بجوسيبول وجوسيبولون حيث ظهرت زيادة معنوية واضحة لحمض اللينوليك في القسم الرئيسي للدهون (جلسريدات ثلاثية) ، ويعطي هذا احتمالية أن مسببات العقم من جوسيبول وجوسيبولون لها تأثير معنوي على ن اد وإنزيمات تعتمد على ن اد الذي لا يسبب العقم ليس له تأثير على إنتاجية الحيوانات المنوية ولا بيئتها من الأحماض الدهنية (أحادية الروابط الغير مشبعة)

Kinetic study and techno-economic indicators for base catalyzed transesterification of Jatropha oil

Fatty acid methyl ester (biodiesel) has been identified as biodiesel alternative fuel obtained from renewable sources. Efforts in Egypt are directed toward the development of new non-edible sources. At the forefront of these non-edible sources comes Jatropha curcas oil (JCO) because it has been grown successfully in Egypt using primary treated municipal wastewater for irrigation. Based on previous research findings for the production of biodiesel from (JCO) using heterogeneous catalyst, some kinetic data on the transesterification reaction were provided. This was achieved by conducting the reaction at various temperatures, reaction time, and dose of catalyst and reactant molar ratios. The transesterification reaction was observed with regard to the percent biodiesel yield versus time and the reaction order was found to be a first order reaction rate equation. Techno-economic indicators revealed that the price of biodiesel produced by heterogeneous base catalyzed method was $0.665/L with a gross profit per year of$37,403,643