Development of a Ti-based alloy: Design and experiment

We proposed the design methodology for titanium-based alloys based on a combination of literature survey, simulation, and experiment. We have selected and investigated the properties of novel Ti-Fe-Zr alloys specifically designed for densification via powder metallurgy techniques. Samples were produced by die compaction of mixed elemental powders with subsequent densification by sintering at 1,275°C in vacuum. Scanning electron microscopy and optical microscopy were used to examine the sintered microstructures to compliment hardness and tensile testing. The results show that density and mechanical properties increase with the iron and zirconium content. The best property combination was obtained with the addition of 5 wt.% iron and 5 wt.% zirconium when vacuum sintered at 1,275°C for 60 min.     

Modified linear prediction algorithm for narrowband interference suppression in universal mobile telecommunication system

Narrow band interference (NBI) deteriorates the quality of the spectrum, leading to a poorer performance of modern universal mobile telecommunication system (UMTS) spread spectrum systems. The linear prediction algorithm is one of the most significant techniques to overcome NBI and enhance the performance of UMTS systems. In this paper, a modified linear prediction algorithm is proposed for NBI suppression in a conditionally stationary environment. This modification improves the error energy estimation in the auto‐regression model of the linear prediction. The convergence of the proposed algorithm is evaluated, and its robustness is verified using Kullback–Leibler metrics for conditionally stationary NBI signals. Computer simulations are carried out, and the obtained results demonstrate the performance of the proposed algorithm and its compliance with UMTS protocols. Copyright © 2012 John Wiley & Sons, Ltd.     

Reuse of RO Desalination Plant Reject Brine

In this work we try to study the feasibility of salt production from a reject brine coming from a desalination plant in Skhira in the south of Tunisia, This plant treats 22,008 m³/day of raw water to produce 9984 m³ of fresh water and 12,024 m³ of rejected water and has the advantages of being environmentally friendly and producing commercial products in crystalline, slurry, and liquid forms. The process involves an application of the solubility diagrams in order to valorize the reject brines. These solutions are considered as strongly concentrated brines and containing several elements such as: Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, and SO₄ ²⁻. This observation leads us to consider the complete hexary system Na⁺, Mg²⁺, K⁺, Ca²⁺/Cl⁻, SO₄ ²⁻//H₂O which includes four quinary systems. A number of physico-chemical analyses were employed (Potentiometry, complexometry, gravimetry, XRD, and SEM). At the end of an isothermal and isobaric evaporation of the reject brine, we could recover various salts (NaCl, KCl, CaSO₄·2H₂O, MgSO₄·7H₂O…) very useful for industry and agriculture.