Effects Zinc oxide (ZnO) of on the mechanical (bending strength and hardness) and thermal stability of hydroxyapatite (HA) that directly synthesized by mechanical milling in a planetary ball mill, using orthophosphoric acid solution (H3PO4) and calcium hydroxide Ca(OH)2 was evaluated. High purity zinc oxide was added in ratios of 10, 30 and 50 percent by weight. HA/ZnO exhibited increasing in microhardness, and bending strength with increasing amount of ZnO addition. X-ray diffraction after sintering at 1100°C for synthesis of hydroxyapatite showed unstable compound, decomposed to β-TCP, while X-ray for the hydroxyapatite ZnO contained thermally stable HA phase and different amounts of ZnO, depending on the amount of ZnO added.
Shape Memory Alloys (SMAs) have been investigated as one of the most full of promise smart materials in multi applications. Among the commercially obtainable Shape Memory Alloys, nickel–titanium (Nitinol or NiTi) ones are wonderful due to their outstanding performance and reliability. In addition to strain recovery, (Ni-Ti) be an attraction in several medical applications due to its biocompatibility, corrosion resistance and fatigue behavior. Low range of transition temperature was the main challenges in the fabrication of these materials. A novel method was introduced to improve the range of transition temperatures by incorporating the shape memory effect into functionally graded materials concept. Therefore, industrialization and implementing of NiTi functionally graded materials made by a powder metallurgy method were carried out through the current work. Two samples with different seven layers of NiTi/NiTi functionally graded materials were compacted using steel die and punch at the same compacted pressure and different sintered temperature. After inspect the different samples of NiTi/NiTi functionally graded materials under different fabrication conditions, the suitability fabrication regime was determined with the aid of microscopic observations. These materials are designed to have gradual or abrupt Microstructural or compositional variations within the body in one piece of material, these samples have been produced by powder metallurgy approach and the effect of composition for each layer studied on the XRD.
Today glass is used in many forms and it has a short life due to brittleness and ease of breakage. After breakage it either store until re-use or send to landfills, since the glass material is un-degradable so its stockpiling in landfills considered an unfriendly solution for the environments, thus there is great need to take advantage of glass waste such as using in mortar and concrete as additive.
This research deals with studying the effect of adding (incandescent lamps) as a glass powder waste to cement mortar on mechanical properties, where the glass waste is used as additive after converting it into micro powder, and mixed with cement in the proportions (0%, 5%, 10%, 15%) and then mixed with sand in 3:1 ratio to create cement mortar and then poured into molds.
And then put in humidity basin and after 24 hours the cubes removed from molds and treated in clean fresh water, saline solution where the salt is 3% NaCl- and finally in basal solution where the base is 3% NaOH- for 7, 28 days, and then mechanical tests is made where the test used in this research is the compressive strength.
It has been noted that there are differences in the compressive strength when immersed in various solvents. The samples submerged with water only have higher strength than that submerged in NaCl solution which in turns have higher strength than that immersed in NaOH, also strength increases with immersion time (i.e. Compressive strength of samples submerged at 28 days better than that submerged at 7 days).
The repression of the spectral line is a matter of main attention in designing of Time Hopping Impulse Radio (TH-IR) Ultra-Wide Band (UWB) systems. This case has been usually processed by randomizing the locations of every pulse. This requires to employ of very long Pseudo Noise (PN) sequences to suppress the capabilities of spectral lines. This research aims to improve the Power Spectral Density (PSD) by constructing the proposed system using Turbo code technique inside MATLAB’s Simulink. We found that our proposed system provides high performance than Conventional PPM-TH-IR in term of eliminating the spectral lines or make it smoother. We also found that the increasing in interleaver length and constraint length enhances PSD.
Functionally graded material (FGM) is new generations of composite materials where the properties are changed linearly according to the change in composition. This work presents the design, fabrication and characterization of multi NiTi shape memory alloys incorporated into single functionally graded materials. This design assumed to improve the general properties of NiTi shape memory alloys, especially the transformation temperature range. These materials are designed to have gradual microstructural or compositional variations within the body in one piece or single material. The powder metallurgy approach has been used extensively in preparing of NiTi alloys as well as the two models of functionally graded materials. The effect of layers composition, sintering time and temperatures was studied on the; microstructure as well as the developmental phases. Corrosion rate and characteristics as well as the toxicity of sintered materials are investigated also. Corrosion test results show that the current of corrosion (Icorr.) for SMA-FGM samples are less than that obtained at each layer (i.e., 19.02, 15.32 μA/cm2 for SMA-FGM1 SMA-FGM2) respectively, and Nickel ions percentage in Ringer solution after corrosion test show SMA-FGM1 SMA-FGM2 samples less than each layer.