In order to implement the concept of sustainability in the field of construction, it is necessary to find an alternative to the materials that cause pollution by manufacturing, the most important of which is cement. Because factory wastes provide siliceous and aluminous materials and contain calcium such as fly ash and slag that are used in the production of high-strength geopolymer concrete with specifications similar to ordinary concrete, it was necessary for developing this type of concrete that is helping to reduce CO2 (dioxide carbon) in the atmosphere. Therefore, the aim of this study was to study the influence of incorporating various percentages of slag as a replacement for fly ash and the effect of slag on mechanical properties. This paper showed the details of the experimental work that has been undertaken to search and make tests the strength of geopolymer mixtures made of fly ash and then replaced fly ash with slag in different percentages. The geopolymer mixes were prepared using a ground granulated blast-furnace slag (GGBFS) blend and low calcium fly ash class F activated by an alkaline solution. The mixture compositions of fly ash to slag were (0.75:0.25, 0.65:0.35, 0.55:0.45) by weight of cementitious materials respectively and compared with reference mix of conventional concrete with mix proportion 1:1.5:3 (cement: sand: coarse agg.), respectively. The copper fiber was used as recycled material from electricity devices wastes such as (machines, motors, wires, and electronic devices) to enhance the mechanical properties of geopolymer concrete. The heat curing system at 40 oC temperature was used. The results revealed that the mix proportion of 0.45 blast furnace slag and 0.55 fly ash produced the best strength results. It also showed that this mix ratio could provide a solution for the need for heat curing for fly ash-based geopolymer.
Background: The incorporation of rubber has not been entirely successful because it can have detrimental effects on the transverse Strength and hence the rigidity of the denture base. Materials and methods: Zirconium oxide nanoparticales were coated with a layer of trimethoxysilylpropylmethacrylate (TMSPM) before sonication in monomer (MMA) with the percentages 3% by weight then mixed with powder using conventional procedure.(100) samples were prepared and divided into five groups according to the test performed ,Each group consisted of 20 specimens and these were subdivided into 2 groupsGroup (A): control group (10 specimens of high impact acrylic resin without zirconium oxide) and Group (B):zirconium oxide group(10 specimens of high impac
... Show MoreIn this work Study effect of annealing temperature on the Structure
of a-Se and electrical properties of a-Se/c-Si hetrojunction have been
studied.The hetrojunction fabricated by deposition of a-Se film on c-
Si using thermal evaporation.
Electrical properties of a-Se/ c-Si heterojunction include I-V
characteristics, in dark at different annealing temperature and C-V
characteristics are considered in the present work.
C-V characteristics suggested that the fabricated diode was
abrupt type, built in potential determined by extrapolation from
1/C2-V curve. The built - in potential (Vbi) for the Se/ Si System
was found to be increase from 1.21 to 1.62eV with increasing of
annealing temperature
Random laser gain media is synthesized with different types of dye at the same concentration (1×10-3 M) as an active material and silicon dioxide NPs (silica SiO2) as scatter centers through the Sol-Gel technique. The prepared samples are tested with UV–Vis spectroscopy, Fluorescence Spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive X-ray Diffraction (EDX). The end result demonstrates that doped dyes with silica nanoparticles at a concentration of 0.0016 mol/ml have lower absorbance and higher fluorescence spectra than pure dyes. FESEM scans revealed that the morphology of nanocrystalline silica is clusters of nano-sized spherical particles in the range (25-67) nm. It is con
... Show MoreUrban Development refers to many topics such as: increased population density, city size, and individual’s production, distribution of technology and the growth of commercial, industrial and service professions. Such development is linked to the coordination of social and cultural trends in order to achieve social progress and economical prosperity. Knowledge as a topic now is known as intellectual capital wich led to upgrae the concept of urban development to be extended into many fields of knowledge, for example, cultural, social and human development to move the level of community culture into a new better standard.
The research adopted the urban transformation based on knowledge as an important factor in gr
... Show MoreThis paper presents a numerical simulation of the flow around elliptic groynes by using CFD software. The flow was simulated in a flume with 4m long, 0.4m wide, and 0.175m high with a constant bed slope. Moreover, the first Groyne placed at 1m from the flow inlet with a constant the Groyne height of 10cm and a 1cm thickness, and the width of Groynes equals 7cm. A submergence ratio of the elliptic Groynes of 75% was assumed, corresponding to a discharge of 0.0057m3/sec. The CFD model showed a good ability to simulate the flow around Groynes with good accuracy. The results of CFD software showed that when using double elliptic Groy
... Show MoreThe studies on unbonded post-tensioned concrete members strengthened with Carbon Fiber Reinforced Polymers (CFRPs) are limited and the effect of strengthening on the strain of unbonded pre-stressed steel is not well characterized. Estimating the flexural capacity of unbound post-tensioned members using the design methodology specified in the design guidelines for FRP strengthening techniques of bonded post-tensioned members does not provide a reliable evaluation. This study investigates the behavior of unbonded post-tensioned concrete members with partial strand damage (14.3% and 28.6% damage) and strengthened with CFRP laminates using a near-surface mounted technique with and without U-wrap anchorages. The experimental results show
... Show MoreThis paper studies the behavior of reinforced Reactive Powder Concrete (RPC) two-way slabs under static and repeated load. The experimental program included testing six simply supported RPC two-way slabs of 1000 mm length, 1000 mm width, and 70 mm thickness. All the tested specimens were identical in their material properties, and reinforcement details except their steel fibers content. They were cast in three pairs, each one had a different steel fibers ratio (0.5 %, 1 %, and 1.5 %) respectively. In each pair, one specimen was tested under static load and the other under five cycles of repeated load (loading-unloading). Static test results revealed that increasing steel fibres volume fraction from 0.5 % to 1 % and from 1% to 1.5%,
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