Durability and chemical resistance of nanoparticles fly ash and silica fume belite cement pastes against sulfate and chloride aggressive media- Part II

The durability (chemical resistence) of the Portland cement (OPC), belite cement (BC) and the optimum belite cement (B4), which their physical and chemo/mechanical properties were perviously investigated in Part I, against 4 % MgSO4 and 4% MgCl2 solutions up to 12 months in terms of compressive strength, total sulfate and total chloride was evaluated and studied. Results showed that the optimum belite cement (B4) containing 15 % High pulverized fly ash (HPFA) and 5 % Silica fume (SF) could be resisted up to 6 months, while that of BC could be withstood only up to 5 months, and the OPC could not resist more than three months of immersion in 4% MgSO4 solution. The compressive strength values exhibited by the samples immesed in sulfate solution at 3, 5 and 6 months of immersion were 83.81, 76.38 and 91.13 MPa, respectively. The same trend was displayed when the same samples were exposed to 4% MgCl2 solution. The compressive strength values exhibited by the same samples exposed to chloride solution at 3, 5 and 6 months of immersion were 84.49, 82.23 and 93.32 MPa, respectively. The total sulfate and chloride contents were enhanced with immesion time up to 12 months, but their values were the minimum with B4 and the maximum with OPC, while with BC were the medium. The optimum cement batch (B4) achieved the highest resistance where it recorded the lowest values for sulfate and chloride ions, but the OPC exhibited the lowest resistance where it recorded the highest values of sulfate and chloride contents at all immersion ages till 12 months.

In vitro biological activity of synthesized silver nanoparticles using Myrtus extract

This study aimed to synthesize and characterize silver nanoparticles (AgNPs) from M. communis laves, and determine their potential activity against human cancer cells as well as leishmanial and bacterial cells. The UV-visible spectroscopy showed an absorption peak at 430 nm wavelengths which is one of the characteristic features of AgNPs. The FESEM image showed irregular shape with a size range of 20-70 nm. MTT results in A172 and MCF-7 cell lines exposed to 5-240 g/mL for 48 hours revealed that M. communis-AgNPs were cytotoxic, with IC50 values of 93.2 g/mL for A172 cell lines and 89.1 g/mL for MCF-7 cell lines, respectively. DCFH-DA analysis showed that 24 h exposure to 25- 200 μg/mL concentrations of AgNPs significantly increased ROS production in cells that indicate oxidative stress induction by AgNPs. M. communis-AgNPs showed overexpression of BCL-2 and Bax genes compared with Glucantime®and negative control (p<0.001) as a potent leishmanicidal and bactericidal activity. The primary modes of action seem to be involved by promotion of the ROS production and up-regulation of BCL-2 and Bax against cancer cell lines. As a result, M. communis-AgNPs formulation should be regarded as a promising agent for potential anti-cancer, anti-leishmanial, and anti-bacterial drugs in therapeutic control programs

Gold nanoparticle–Quercetin composite formulation: A Computational Model Structure

Nanoparticle mediated drug delivery is an emerging area of research now a days. In our present study, we emphasized on the mode of interaction of a widely used drug, Quercetin with frequently worked metallic nanoparticle, Gold (Au). At first five –OH groups have been attached separately with gold atom and energy minimization was performed using Avogadro Software for windows system. From this, we found that the –OH groups present at 7 position of ‘A’ ring, 3’ and 4’ positions of ‘B’ ring are most suitable site for gold atom to bind. In the next level of study, a gold atom has been interacted with two quercetin molecules at a time. The gold atom was attached to –OH group of 7 position of one quercetin molecule and 4’ position of the other. The calculated energy was found to be 482.319 KJ/Mol. Further, gold atoms were interacted with all –OH groups of quercetin molecule at a time to see its stability and the structure was found to have quite stable with an energy level of 218.074 KJ/Mol. Lastly we tried to make a quercetin–gold nanoparticle model structure which mimics the actual nanocomposite synthesized in vitro where one gold atom was interacted with two quercetin molecules and the other –OH groups of quercetin molecules were again attached with gold atoms. This structure possesses energy of 439.880 KJ/Mol. The bond lengths and bond angle of interacting C, O and Au atoms were measured to characterize the complex.

Effect of Nano Materials on Performance Characteristics of High Strength Self Compacting Concrete

In today's fast-growing world, it is critical to utilize green, sustainable, and resilient materials keeping the impact of carbon in mind. The use of Nanomaterials has evolved to improve the performance characteristics of cement composites. As a result, Graphene Oxide (G.O) was discovered to be one of the Nanomaterials with an exceptional variety of characteristics with the potential to improve the strength and toughness of cement-based composites. Nano-material concrete is a new kind of concrete composed of materials with Nano scale particle sizes. Graphene Oxide can be used in concrete to create high strength concrete. The mix design was calculated for M80 by substituting 15% cement with Fly Ash and another 15% cement with Ground Granulated Blast Furnace Slag (GGBS or GGBFS) to get High Strength Self-Compacting Concrete (HSSCC). In this paper, Graphene Oxide was added in 0%, 0.02%, 0.04%, 0.06%, 0.08% and 0.1% by weight of powder content to the Self Compacting Concrete. Fresh properties were determined by performing Slump Flow test, V-Funnel test, and L-Box test. Hardened properties were determined by conducting compression test, split tensile test and flexural test at 7 days and 28 days of age. By inclusion of Graphene Oxide to the self-compacting concrete, desired properties were achieved.

Synthesis and characterization of stable aqueous dispersion of silver nanoparticle from citrullus vulgaris seed oil via lecithin

Nanoparticles are known to be of wide applications in various fields of human endeavours. Many methods of syntheses such as physical, chemical are harmful to the environment, thus, this study utilised green production of nanoparticles via waste product such as Citrulus vulgaris seed. Oil was extracted using soxhlet extractor from the prepared Citrulus vulgaris seed. Physico-chemical properties such as percentage yield, acid value, peroxide value were carried out on the Citrulus vulgaris seed oil. Citrulus vulgaris was further processed to form lecithin. The lecithin extracted was characterized for colour, Peroxide Value, Acetone Insoluble (AI), Acid Value, solubility in water and organic solvents. The result of the physico-chemical parameters was in conformity with the standard and various literatures. Therefore, lecithin is processed into dispersed aqueous silver nanoparticles by the addition of silver nitrate. The chemical reaction was monitored progressively using visual assessment, UV-visible and FTIR Spectroscopy. The size and surface of the dispersed silver nanoparticles produced was analysed using Atomic Force Microscopy. Therefore, a dispersed aqueous silver nanoparticle was produced from lecithin made from Citrulus vulgaris seed oil.

Physical and Chemo/Mechanical behaviors of fly ash and silica fume belite cement pastes- Part I

Physical, chemical and mechanical properties of high belite cement (HBC) blended with high pulverized fly ash (HPFA) with stable ratio of silica fume (SF) in comparison with Portland cement (OPC) were investigated. Results showed that the water of consistency and setting times (Initial and final) tended to increase with the increase of HPFA content. The bulk density and compressive strength were also improved and enhanced with the increase of HPFS content at all hydration times, but only up to 15 % HPFA, and then decreased with further increase. However, the total porosity slightly decreased, but started to increase with further increase of >15 % HPFA. The free lime content of the pure OPC and HBC gradually were increased as the hydration times progressed up to 90 days, while those of blended cements increased only up to 7 days and then decreased onward. The results were confirmed by measuring the heat of hydration and ultrasonic pulse velocity for the optimum cement pastes comparing with those of both OPC and HBC. The heat of hydration of the optimum cement pastes was decreased at all hydration times and become lower than those of OPC and HBC. The ultrasonic pulse velocity test (USPV) proved that the uniformity and quality of the matrix of the hardened cement pastes are good with no cracks.

Synthesis and Characterizations of Cadmium Doped Aluminium Oxide Nanoparticles

The cadmium doped aluminium oxide (CdAl2O3) nanoparticles were prepared by reverse precipitation method. The prepared CdAl2O3 nanoparticles were characterized by Powder X-Ray Diffraction in order to confirm the crystalline nature of the sample and found average crystallite size in the range 27.6 nm. Fourier transform infrared spectroscopy confirms the presence of metal oxygen bonds in the CdAl2O3 nanoparticle.

Structural and optical characteristic of 1-(4-Methylsulfonyl Phenyl)-3-(4-n, n Dimethyl (amino Phenyl)-2-Propen- 1-One (MSPPP) Chalcone doped ZnO nanoparticles

The purpose of this paper is to investigate the structural and optical characteristics of 1-(4-Methylsulfonyl Phenyl)-3-(4-n, n Dimethyl (amino Phenyl)-2-Propen- 1-One (MSPPP) Chalcone doped in ZnO nanoparticles. Part of the aim is to study the characterization of chalcone doped ZnO nanoparticles by several techniques such as X-ray diffraction, Scanning electron microscope, FTIR spectroscopy, and diffuse reflection spectra. All doped samples showed a hexagonal wurtzite structure. This study has shown that the crystallite size of pure ZnO varied from 23.50 to 27.45 nm and when increasing the chalcone percentage by 0.5 and 1.5%, has increased the crystallite sizes in the range of 33.40–33.80 nm and 33.80–36.20 nm, respectively. The value of the energy gap (Eg) for ZnO nanoparticles was 3.14 eV. For 0.5 and 1.5% chalcone doped ZnO, the energy gap decreased by an order of magnitude 0.16 eV.

Extraction of lignin from wastes of sugarcane bagasse and its utilization as an admixture for Portland cement

The influence of the prepared carboxy-methylated lignin extracted from sugarcane bagasse was investigated. Results showed that the w/c ratio and also setting times of the blank (L0) were reduced with the lignin content. The heat of hydration, combined water content, bulk density and compressive strength of the blank (L0) slightly increased with increasing of lignin content, but only up to 0.3 % lignin (L5) and then decreased. The free lime content decreased with the lignin content nearly at all hydration times up to 90 days due to the gradual reduction of the cement portion. The total porosity of the blank (L0) reduced gradually with lignin content up to 0.3 % lignin, and then increased with further increase of lignin. The FTIR spectra illustrated that the rate of hydration increased with lignin content. The SEM-EDAX image analysis showed the improved microstructure of cement pastes in presence of carboxy-methylated lignin when compared with that of the blank.

Petrological, Chemical, and Mineralogical Characterization of Anka (Zamfara State) Manganese Ore

Manganese deposit reserves exist in Nigeria, which have potentials as raw materials for industrial applications such as batteries, steel and electrical appliances. The present level of exploitation of Manganese is very low and, in most cases, appropriate processing would be necessary to attain desirable qualities. This paper provides petrological, chemical and mineralogical characterization of manganese ore in Anka area of Zamfara state, Nigeria. A chip of about 1/8 of an inch and about 1 inch by 1 inch was cut from the lumps of Anka (Zamfara state) manganese sample using rock cutter, after which their surfaces were trimmed and the chip was mounted on a grinding machine to make the surface smooth. The samples were mounted on a slide and viewed using Leica Petrological Microscope. 500 g of the ore was weighed using digital weighing balance. The sample was crushed and ground until 80% passing of 250µm is achieved. The ground ore was blended homogenously before the analysis while for the ore microscopy study, true fraction representative of the manganese ore samples were prepared, polished mounts and characterized using Scanning Electron Microscope-energy dispersed X-ray (SEM/EDX). However, X-ray Fluorescence was used to determine the chemical composition while identification of the associate mineral phase was done using X-ray Diffraction. From the petrological analysis carried out on the crude samples reveals the presence of heavy mineral and segregation distribution of the mineral. The XRF results shows 77.81% MnO, 60.26% Mn, 10.9% Fe2O3, 4% Al2O3 while Spessartine (3MnO.Al2O3, 0.830), Silicon oxide (SiO2, 1.122), Quartz (SiO4, 0.728), Pyrolusite (MnO, 1.543), and Almandine (Fe3Al2SiO12, 1.583) were identified as the major phases in the ore.