Pub Date : 2024-07-22DOI: 10.21608/ajst.2024.290876.1032
H.A Fetouh
: This systematic review presenting fundamentals of geopolymer (GP) for concrete technology. Geopolymer formulated by activation of sustainable aluminosilicate (minerals) binders (eco-friendly, available, cheap, sustainable natural raw materials fly ash and slag wastes). Geopolymer concrete decrease scarcity of global ordinary Portland cement and decrease energy 0.110 kWh per gram and CO 2(g) emission (800 kg ton -1 ). Durability, mechanical strength, resistance to water and leaching improved via by TiO 2 nanoparticles as nanofiller. Polycondensation yield and physicochemical characteristics of GP are monotonic functions of (binder's chemistry, alkali concentration& types, reinforcing fibers, Si to Al ratio, precursors firing, types of solid wastes, heating activation, types and curing conditions. Concrete quality is controlled by geopolymer (composition, additives, mechanical strength and compressive strength). Nano fillers materials SiO 2 , Fe 2 O 4 and Al 2 O 3 improved (mechanical characteristics, microstructure, functionality, durability, mortar strength, slurry mobility, permeability, impact
:这篇系统性综述介绍了混凝土技术中土工聚合物（GP）的基本原理。土工聚合物通过活化可持续的铝硅酸盐（矿物）粘结剂（生态友好、可用、廉价、可持续的天然原料粉煤灰和矿渣废料）配制而成。土工聚合物混凝土减少了全球普通硅酸盐水泥的稀缺性，并降低了每克 0.110 千瓦时的能耗和二氧化碳排放量（800 千克/吨-1）。纳米填充物 TiO 2 纳米颗粒提高了混凝土的耐久性、机械强度、耐水性和耐沥滤性。土工聚合材料的缩聚率和理化特性与下列因素有关：粘结剂的化学成分、碱的浓度和类型、增强纤维、硅铝比、前驱体的烧制、固体废弃物的类型、加热活化、类型和固化条件。混凝土质量由土工聚合物（成分、添加剂、机械强度和抗压强度）控制。纳米填充材料 SiO 2、Fe 2 O 4 和 Al 2 O 3 改善了混凝土的机械特性、微观结构、功能性、耐久性、砂浆强度、泥浆流动性、渗透性、抗冲击性和耐久性。
{"title":"Geopolymers as sustainable alternates for portland cement in constructive concrete: systematic review","authors":"H.A Fetouh","doi":"10.21608/ajst.2024.290876.1032","DOIUrl":"https://doi.org/10.21608/ajst.2024.290876.1032","url":null,"abstract":": This systematic review presenting fundamentals of geopolymer (GP) for concrete technology. Geopolymer formulated by activation of sustainable aluminosilicate (minerals) binders (eco-friendly, available, cheap, sustainable natural raw materials fly ash and slag wastes). Geopolymer concrete decrease scarcity of global ordinary Portland cement and decrease energy 0.110 kWh per gram and CO 2(g) emission (800 kg ton -1 ). Durability, mechanical strength, resistance to water and leaching improved via by TiO 2 nanoparticles as nanofiller. Polycondensation yield and physicochemical characteristics of GP are monotonic functions of (binder's chemistry, alkali concentration& types, reinforcing fibers, Si to Al ratio, precursors firing, types of solid wastes, heating activation, types and curing conditions. Concrete quality is controlled by geopolymer (composition, additives, mechanical strength and compressive strength). Nano fillers materials SiO 2 , Fe 2 O 4 and Al 2 O 3 improved (mechanical characteristics, microstructure, functionality, durability, mortar strength, slurry mobility, permeability, impact","PeriodicalId":504746,"journal":{"name":"Alexandria Journal of Science and Technology","volume":"70 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141817593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-13DOI: 10.21608/ajst.2024.257728.1024
Heba Mohamed, Bassma H. Elwakil, Mohamed A. Hagar, M. Aouad, N. Rezki, Z. Olama, Y. El Kilany, Mohamed A. Zakaria
: Drug resistance is a major global problem leading to higher morbidity and mortality rates especially among hospitalized patients. Hence, in the present study, 1,2,3-Triazole-acetophnone molecular conjugates 3a-c were resynthesized and then used in nanoformulated composites ( 3a-cCNPs) using chitosan as a matrix to give nano compounds of particle sizes ranging from 20 to 40 nm. Antimicrobial activity of the synthesized compounds and the nanoformulated analogues against some multi-drug resistant microbes revealed that 3bCNPs was the most potent candidate due to its high efficiency against multi-drug resistant (MDR) microbes that reached complete microbial cells eradication after 4 hours. The synthesized nanoparticles
{"title":"Novel Chitosan Nanoparticles based 1,2,3-triazole moieties as potent drugs against multi-drug resistant bacteria","authors":"Heba Mohamed, Bassma H. Elwakil, Mohamed A. Hagar, M. Aouad, N. Rezki, Z. Olama, Y. El Kilany, Mohamed A. Zakaria","doi":"10.21608/ajst.2024.257728.1024","DOIUrl":"https://doi.org/10.21608/ajst.2024.257728.1024","url":null,"abstract":": Drug resistance is a major global problem leading to higher morbidity and mortality rates especially among hospitalized patients. Hence, in the present study, 1,2,3-Triazole-acetophnone molecular conjugates 3a-c were resynthesized and then used in nanoformulated composites ( 3a-cCNPs) using chitosan as a matrix to give nano compounds of particle sizes ranging from 20 to 40 nm. Antimicrobial activity of the synthesized compounds and the nanoformulated analogues against some multi-drug resistant microbes revealed that 3bCNPs was the most potent candidate due to its high efficiency against multi-drug resistant (MDR) microbes that reached complete microbial cells eradication after 4 hours. The synthesized nanoparticles","PeriodicalId":504746,"journal":{"name":"Alexandria Journal of Science and Technology","volume":"81 S363","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140393774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. ABSTRACT: This research was planned to isolate a marine bacterium that is able to biosynthesize silver nanoparticles to be used for therapeutic applications. The environmentally friendly production of nanoparticles from biological sources is frequently simple, inexpensive, and free of hazardous chemicals. Silver nanoparticles (AgNPs) are part of a new class of biomaterials that is being created more and more for use in scientific and medical endeavours. Given how important the biological system is, it is essential to have a basic understanding of how inorganic nanoparticles affect cellular development and function. Resazurin, a rapid screening assay, was applied to evaluate the antibacterial effects of the synthesized AgNPs against the pathogenic microbes. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay was utilized to test silver nanoparticles for cell cytotoxicity and anticancer activity. Silver nanoparticles (AgNPs) were tested for wound healing effects using a scratch assay on a human epithelial cell line (WISH-CCL-25). Halomonas sp. FSSH, among many isolates successfully biosynthesized silver nanoparticles with interesting properties. The present finding revealed that supernatant of Halomonas sp. FSSH could be effectively used as a reducing agent for the green production of AgNPs. These AgNPs are considered efficient antimicrobial, anticancer, and wound-healing agents without cytotoxic effects .
{"title":"Laboratory-synthesized biogenic silver nanoparticles (AgNPs) with potential therapeutic applications","authors":"Fatima Hamed, Hanan Ghozlan, Soraya Sabry, Samia Abouelkhir","doi":"10.21608/ajst.2024.260958.1025","DOIUrl":"https://doi.org/10.21608/ajst.2024.260958.1025","url":null,"abstract":". ABSTRACT: This research was planned to isolate a marine bacterium that is able to biosynthesize silver nanoparticles to be used for therapeutic applications. The environmentally friendly production of nanoparticles from biological sources is frequently simple, inexpensive, and free of hazardous chemicals. Silver nanoparticles (AgNPs) are part of a new class of biomaterials that is being created more and more for use in scientific and medical endeavours. Given how important the biological system is, it is essential to have a basic understanding of how inorganic nanoparticles affect cellular development and function. Resazurin, a rapid screening assay, was applied to evaluate the antibacterial effects of the synthesized AgNPs against the pathogenic microbes. The 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay was utilized to test silver nanoparticles for cell cytotoxicity and anticancer activity. Silver nanoparticles (AgNPs) were tested for wound healing effects using a scratch assay on a human epithelial cell line (WISH-CCL-25). Halomonas sp. FSSH, among many isolates successfully biosynthesized silver nanoparticles with interesting properties. The present finding revealed that supernatant of Halomonas sp. FSSH could be effectively used as a reducing agent for the green production of AgNPs. These AgNPs are considered efficient antimicrobial, anticancer, and wound-healing agents without cytotoxic effects .","PeriodicalId":504746,"journal":{"name":"Alexandria Journal of Science and Technology","volume":"11 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140434762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-22DOI: 10.21608/ajst.2024.257068.1023
Esraa Elghanam, Ahmed M. A. El-Sayed, Mahmoud Elalem
: Here we study the existence of solution and its continuous dependence of a constrained problem of a nonlinear functional integral equation subject to a constraint of an initial value problem of a pantograph differential equation. The Hyers-Ulam stability of the problem will be proved.
{"title":"A constrained problem of a nonlinear functional integral equation subject to the pantograph problem","authors":"Esraa Elghanam, Ahmed M. A. El-Sayed, Mahmoud Elalem","doi":"10.21608/ajst.2024.257068.1023","DOIUrl":"https://doi.org/10.21608/ajst.2024.257068.1023","url":null,"abstract":": Here we study the existence of solution and its continuous dependence of a constrained problem of a nonlinear functional integral equation subject to a constraint of an initial value problem of a pantograph differential equation. The Hyers-Ulam stability of the problem will be proved.","PeriodicalId":504746,"journal":{"name":"Alexandria Journal of Science and Technology","volume":"70 11-12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140499200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-17DOI: 10.21608/ajst.2024.252610.1022
Shaymaa Nasim, Ahmed M. A. El-Sayed, Wagdy El-Sayed
: In this paper we study the initial-value problem of the fractal differential equation
:在本文中，我们研究了分形微分方程的初值问题
{"title":"Solvability of an Initial-value Problem of Non-linear Implicit Fractal Differential Equation","authors":"Shaymaa Nasim, Ahmed M. A. El-Sayed, Wagdy El-Sayed","doi":"10.21608/ajst.2024.252610.1022","DOIUrl":"https://doi.org/10.21608/ajst.2024.252610.1022","url":null,"abstract":": In this paper we study the initial-value problem of the fractal differential equation","PeriodicalId":504746,"journal":{"name":"Alexandria Journal of Science and Technology","volume":" 706","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139617454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-16DOI: 10.21608/ajst.2024.250598.1021
Malak M. S. Ba-Ali
: In this work, we use the De Blasi measure of noncompactness and Darbo fixed point Theorem to study the existence of solutions for an initial value problem of a delay implicit functional integro-differential equation. The sufficient condition for the uniqueness of the solution will be given. The continuous dependence of the unique solution on some data will be studied.
:在这项工作中，我们利用非紧凑性的 De Blasi 度量和 Darbo 定点定理来研究延迟隐式函数积分微分方程初值问题解的存在性。将给出解唯一性的充分条件。还将研究唯一解对某些数据的连续依赖性。
{"title":"On a Delay Implicit Functional Integro - Differential Equation","authors":"Malak M. S. Ba-Ali","doi":"10.21608/ajst.2024.250598.1021","DOIUrl":"https://doi.org/10.21608/ajst.2024.250598.1021","url":null,"abstract":": In this work, we use the De Blasi measure of noncompactness and Darbo fixed point Theorem to study the existence of solutions for an initial value problem of a delay implicit functional integro-differential equation. The sufficient condition for the uniqueness of the solution will be given. The continuous dependence of the unique solution on some data will be studied.","PeriodicalId":504746,"journal":{"name":"Alexandria Journal of Science and Technology","volume":"42 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140505992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-01-03DOI: 10.21608/ajst.2024.333736
magdy feshar, Fatma Mahgoub, Ashraf Abdel-Gaber
: The principal aim of this research is to meticulously detect and comprehend the reasons behind the longitudinal facial crack (LFC) defect during the casting of low-carbon, low-manganese flat steel products. The overarching goal is to mitigate the likelihood of the defect occurring by optimizing key process parameters. Even seemingly minor defects are considered unfavorable in the final product due to the substantial manufacturing losses entailing economic repercussions. The research employs a diverse array of techniques, including the utilization of a scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), potentiodynamic polarization curve measurements, and electrochemical impedance spectroscopy
:这项研究的主要目的是在铸造低碳低锰扁钢产品的过程中，仔细检测并理解产生纵向表面裂纹（LFC）缺陷的原因。首要目标是通过优化关键工艺参数来降低缺陷发生的可能性。即使是看似微小的缺陷，在最终产品中也会被认为是不利的，因为会造成巨大的生产损失和经济影响。研究采用了多种技术，包括扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDX)、电位极化曲线测量和电化学阻抗光谱。
{"title":"Optimization of the Steel Casting Process Parameters to Control the Longitudinal Facial Crack (LFC) Defect Appearance","authors":"magdy feshar, Fatma Mahgoub, Ashraf Abdel-Gaber","doi":"10.21608/ajst.2024.333736","DOIUrl":"https://doi.org/10.21608/ajst.2024.333736","url":null,"abstract":": The principal aim of this research is to meticulously detect and comprehend the reasons behind the longitudinal facial crack (LFC) defect during the casting of low-carbon, low-manganese flat steel products. The overarching goal is to mitigate the likelihood of the defect occurring by optimizing key process parameters. Even seemingly minor defects are considered unfavorable in the final product due to the substantial manufacturing losses entailing economic repercussions. The research employs a diverse array of techniques, including the utilization of a scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), potentiodynamic polarization curve measurements, and electrochemical impedance spectroscopy","PeriodicalId":504746,"journal":{"name":"Alexandria Journal of Science and Technology","volume":"35 26","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139389128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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