ملخص البحث :

Silica is considered one of the most prevalent components in the Earth’s shell and is synthesized for use in technological applications. Nevertheless, new methods for finding a better, cheaper, and more ecologically friendly supply of silica with less energy consumption are unavoidable. This study investigates whether nanopowders made from waste with a great silica amount (fly ash and glass) can be utilized as fillers in an epoxy glue to enhance its characteristics. Four different contents (5, 10, 15, and 20 wt%) of nano–fly ash, nanoglass, and nanosilica powder were introduced into the samples. Fourier transform infrared analysis, differential scanning calorimetry analysis, viscosity testing, and microhardness testing were conducted for nanoglass/epoxy and nano–fly ash/epoxy samples, which were compared with the silica/epoxy samples. Results indicated that the nanoglass and nano–fly ash powder have the same impact as nanosilica on the characteristics of epoxy. The hardness and viscosity of epoxy increased with the increase in the added filler. At 20 wt%, the hardness value of the nanoglass/epoxy composites was greater than that of the nanosilica/epoxy and fly ash/epoxy composites by about 15% and 7%, respectively. The results also indicated that the highest viscosity values were obtained when using nano–fly ash powder of 20 wt%. Furthermore, the modification of the epoxy by the nanoparticles had no significant effect on the values of the glass transition temperatures.

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In this study, polymer composites were manufactured with epoxy-based resin and wastes as a mineral additive. The wastes including a high content of silica (Silica fume, glass and fly ash) powder were used as fillers for an epoxy adhesive to improve its wear resistance properties. They were supplemented to mixes in various ratios via substituting the resin from 0 to 20% by weight. Tests of wear rate and hardness were conducted upon all-polymer composites at all fillers ratios. Results indicated that the epoxy hardness increased with increasing the filler addition. Consequently, the addition of wastes that include silica raised the wear resistance of polymer composites; nevertheless, it caused the composites harder materials. The wear rate decreased with increasing the silica fume, glass, and fly ash addition. In the case of fly ash addition, the minimum wear rate was at 15%, and after this percentage, the wear rate increased. However, in the case of glass addition, the minimum wear rate was at 10%, and after this percentage, the wear rate increased.

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This paper investigates the effect of nano-papyrus cane ash as an additive on concretes’ mechanical and physical properties. Three types of concrete mixtures, 1:2:4, 1:1.5:3, and 1:1:2 were prepared for each mixture, nano-papyrus ash was added in five different dosages of 0.75, 1.5, 3, 4.5, and 6% by weight of cement; therefore, eighteen mixes would be studied in this work. Physical properties represented by dry density and slump were also measured for each mix. Moreover, to evaluate the mechanical properties development split tensile strength and compressive strength were obtained at age (7 and 28). Results manifested that the adding of nano ash developed the compressive strength and split tensile strength of concrete and the maximum enhancement recognized in the mixes with a content of 4.5% nano-papyrus in each studied mixture in this work. The slump test results indicated that the workability of concrete increased with adding nano-papyrus ash gradually with increasing nanoparticles' content. As well as, dry density was significant increased with nano-papyrus ratio; greater values were recorded in mixtures with 1.5-4.5% content of nano-papyrus. When comparing the concrete mixes used, it was found that the best results were obtained with 1:1:2 mixtures. This remarkable improvement in concrete properties considers the nano-papyrus is considered a cement economical and useful replacement for traditional construction material.

ملخص البحث :

In the present study, the compressive strength assessments of cement mortar containing different amounts of ZrO2, SiO2, Al2O3 and CaCO3 nanoparticles have been investigated. Four different contents for each nanoparticles type were utilized as a partial replacement of cement 1%, 1.5%, 3% and 5% by the cement weight. The compressive strength was estimated for two ages (7) and (28) days. The end results manifested that the specimens’ compressive strength enhanced via the addition of the nanoparticles of ZrO2 and SiO2 to the paste of cement till 3.0% and then decreased but remained greater than the reference mix. While, the compressive strength of specimens enhanced via the addition of the nanoparticles of Al2O3 and CaCO3 ZrO2 up to 5%. Maximum compressive strength recorded was 42.5 MPa for mixes with 3% nano SiO2 followed by 38 MPa, 37 MPa and 33.5 MPa for mixes with 4% nano Al2O3, 3% nano and ZrO2 and 4% nano CaCO3, respectively.

ملخص البحث :

To study the effects of nanomaterials on the microscopic structure of the mortar interconnection zone that is prepared by a compound bond comprising nanomaterials. And to clarify its impact on compressive strength improvement. In this study, the compressive strength, SEM analysis and XRD analysis were estimated for mortar containing different amounts of ZrO2, SiO2, Al2O3 and CaCO3 nanoparticles. Four different contents of each nanoparticles' types were used as a partial replacement of cement with 1%, 1.5%, 3% and 5% by the weight of cement. Results manifested that the mortar compressive strength enhancement can be ascribed to the microstructure amelioration of the interfacial transition region. Besides, XRD analysis and SEM micrographs elucidated the formation of hydration compounds and the improvement in bonding due to the existence of nanoparticles.

ملخص البحث :

Cement production uses large quantities of natural resources and contributes to the release of CO2. In order to treat the environmental effects related to cement manufacturing, there is a need to improve alternative binders to make concrete. Accordingly, extensive study is ongoing into the utilization of cement replacements, using many waste materials and industrial. This paper introduces the results of experimental investigations upon the mortar study with the partial cement replacement. Fly ash, silica fume and glass powder were used as a partial replacement, and cement was replaced by 0%, 1%, 1.5%, 3% and 5% of each replacement by the weight. Compressive strength test was conducted upon specimens at the age of 7 and 28 days. Microstructural characteristic of the modified mortar was done through the scanning electron microscope (SEM) vision, and X-ray diffraction (XRD) analysis was carried out for mixes with different replacements. The tests results were compared with the control mix. The results manifested that all replacements present the development of strength; this improvement was less in the early ages and raised at the higher ages in comparison with the control specimens. Microstructural analysis showed the formation of hydration compounds in mortar paste for each replacement. This study concluded that the strength significantly improved by adding 5% of silica fume compared with fly ash and glass powder.

ملخص البحث :

The technological effect of porous implants in biomedical applications has stepped up the look for advanced shaping tools. The present work was mostly concerned on create and control on porosity and surface roughness of zirconia structures that production by electrophoretic deposition (EPD) technique. Distilled water is utilized in this study to help to create the porosity and increase the surface roughness by its addition in little amounts to ethanol suspension. The obtained porous structures were investigated using SEM and AFM analyses. The addition of water affected the properties of the alcohol suspension, reducing the pH and increasing the dielectric constant. The results show that even adding a small amount of water to an electrolytic suspension leads to gas release on the electrode. The resulted zirconia structures showed the 1 ml water addition was the ultimate value to create uniform pores on the deposited part in the case of 0.5 g zirconia powder volume.

ملخص البحث :

Sustainability and reducing environmental damage caused by CO2 emissions have become issues of interest to researchers in the construction sector around the world. Reducing the cement content in concrete by partially substituting it with by-products or waste falls within this field as the cement industry is responsible for 7% of global CO2 emissions. On the other hand, self-compacting concrete (SCC) is one of the special types of concrete that contains a large amount of powder (most of which is cement) to ensure its flow under the influence of its weight without separating its components. Therefore, to produce eco-friendly SCC, many researchers have replaced part of the cement with clay brick waste powder (CBWP) since brick units are among the most widely used building materials after concrete. Accordingly, this study aims to review previous research that included using CBWP in SCC. The effect of these wastes on the fresh, mechanical, durability and microstructural properties of cement was reviewed. Additionally, a comparison between the environmental impacts of SCCs with different CBWP contents has been conducted using the life cycle assessment (LCA) approach. It was found that the highest value of CBWP that can be used without negatively affecting the different properties of concrete is 10% by weight of cement. Moreover, regarding environmental impact, using CBWP as a substitute for cement reduces environmental damage, and the lowest environmental impact that can be achieved per strength unit (MPa) is 37.5%.

ملخص البحث :

This work is a study of the effect of polyethylene glycol (PEG) on electrophoretic deposition ) EPD) of alumina and zirconia particles. The effect of polyethylene glycol as a binder material and the toluene as a dielectric liquid, on the pH of suspension, the final thickness and green density of the deposed parts were studied. There was a difference in the behavior of polyethylene glycol when added for the alumina suspension and the zirconia suspension. The increase in polyethylene glycol was useful to deposit the zirconia more than alumina. The pH for both alumina and zirconia suspension increases with the increase of polyethylene glycol content and with the addition of toluene due to increase of the OH– concentration in the suspension. This increase of pH enhances the particle surface charge and enhances the deposition rate, which led to the increase of density of the deposit.

ملخص البحث :

Electrophoretic deposition (EPD) technique is used to prepare zirconia–alumina composite layers based on the principle of functionally graded materials (FGM). The FGM were prepared with five layers. The outer layer was composed of pure α-alumina to promote biocompatibility while the inner layer was stabilised zirconia (3Y-TZP), to benefit from its tough properties. The intermediate layers were stepwise graded layers. The stability of the EPD suspensions was the main challenge during the preparation steps. Due to availability and low cost, alcoholic solutions of polyethylene glycol (PEG) and toluene were used to control conductivity, dielectric constant and the viscosity of the suspension. The appropriately applied potential, (ζ), for the deposition of each layer, was achieved via gradation of the applied voltage, which was to optimise the packing of each layer and avoid cracking after sintering at 1500 °C. The cylindrical-shaped green specimens were obtained via deposition on graphite electrodes. A small amount of acetic acid was added during the deposition of the final outer alumina layer to introduce porosity, via the bubbling of acetic acid, to encourage osseointegration. The sintered specimens were implanted in rabbit tibial bone. In vivo histological tests showed the successful osseointegration of the implants to the rabbit bone.

ملخص البحث :

This paper provides an overview of the mechanical properties of reinforced Al- 12%Si alloy by uni-directional of the eutectic phases in specific direction. A special solidification unit have been designed and manufactured to ensure the correct orientation of growing eutectic phase. Two types of insulation materials have been used to isolate the carbon steel mold of solidification unit, (dry sand and glass wool). The second type insulator found to be favorable in augmenting the growth and unidirection of eutectic phase with the conditions of cold water flow through the unit. The produced microstructure consists of little elongated α-phase with a noticeable correct orientation of the growing discontinuous eutectic phase in the direction of heat sink. Hardness, tension, compression and impact properties have improved in comparison with the samples of free mold isolation case (i.e. free solidification). These results reflect directly the effect of uni-directional growth of eutectic phase in the reinforcement process of the investigated alloy as an in situ-composite material.

ملخص البحث :

Electrophoretic deposition (EPD) is continued to be a major activity of science and technology in view of its advantages of controlling the deposit thickness, morphology, and microstructure. The method enables the formation of films on substrates of complex geometry that suits for various applications including biomaterials. However, the method involves controlling of various process parameters, which are of vital effects on the properties of the deposit. Besides, deposition of zirconia nano particles is vital for production of parts used in restorative dentistry. This work was a study the effect of polyethylene glycol polymer as a binder-suspension agent, the amount the solid loading (zirconia particles), and the effect of the toluene as a dielectric liquid, on the final thickness and green density of the deposed parts.

ملخص البحث :

Electrophoretic deposition (EDP) is gaining increasing attention both in science and industry because this method has allowed the formation of thin films or multilayer films of controlled thickness and morphology. The method enables the formation of films on substrates of complex geometry that suits for various applications. This work is a study the effect of polyethylene glycol as a binder-suspension agent, the amount the solid loading (alumina particles), and the effect of the toluene as a dielectric liquid, on the pH of suspension, the final thickness and green density of the deposed parts. It has been shown that a certain amount of polyethylene glycol when added to ethanol or ethanol- 30%toluene has given good results for both the green density and the thickness.

ملخص البحث :

In this paper, mixing of the recycled glass, which possesses a high SiO2 (silicon dioxide) percentage, was utilized to produce a green concrete with remarkable properties. Waste glasses were utilized as cement or fine aggregate partial replacement with various contents (5%, 10%, 15% and 20%) via the weight of cement or fine aggregate. The compressive strength for three ages (7, 14, and 28) days and slump was measured for each concrete mix. Results evinced that the recorded compressive strength increased with the glass content up to10% and then decreased when using glass as replacement of cement, while when using glass as replacement for fine aggregate, the compressive strength decreased initially and then increased with the content of glass. The results of slump test manifested that the concrete workability increased with the content of glass whether the powder of glass employed as cement or fine aggregate replacement.