The present work aimed to study the efficiency of nanofiltration (NF) and reverse osmosis (RO) membrane for heavy metal removal from wastewater and study the factors affecting the performance of these two membranes: feed concentrations for heavy metal ions, pressure, and flow rate. The experimental results showed, heavy metals concentration in permeate increase with raise in feed concentrations, decline with increase in flow rate. The raise of pressure, heavy metals concentration decreases for RO membrane, but for NF membrane the concentration decrease and then at high pressure increase. The rejection percentage for chromium in NF and RO is 99.7% and 99.9%, for copper is 98.4% and 99.3%, for zinc is 97.9% and 99.5%, for nickel is 97.2% and

Abstract

Theoretical and experimental methodologies were assessed to test curved beam made of layered   composite material. The maximum stress and maximum deflection were computed for each layer and the effect of radius of curvature and curve shape on them. Because of the increase of the use of composite materials in aircraft structures and the renewed interest in these types of problems, the presented theoretical assessment was made using three different approaches: curved beam theory and an approximate 2D strength of material equations and finite element method (FEM) analysis by ANSYS 14.5 program for twelve cases of multi-layered cylindrical shell panel differs in fibe

The results of theoretical and experimental investigations carried out to study the effect of load and relative sliding speed on the abrasive wear behavior in drilling bit teeth surfaces of an insert tungsten carbide bit have been presented. Experimentally, an apparatus for abrasive wear tests conducted on the modified ASTM-G65 was modified and fabricated to facilitate loading and measurement of wear rate for the sand/ steel wheel abrasion test, which involves two cases of contact; first is at dry sand and second is under wet condition. These tests have been carried under varied operating parameters of normal load and sliding speed. A theoretical model based upon the Archard equation has been developed for predicting wear simulation by u

In the recent decade, injection of nanoparticles (NPs) into underground formation as liquid nanodispersions has been suggested as a smart alternative for conventional methods in tertiary oil recovery projects from mature oil reservoirs. Such reservoirs, however, are strong candidates for carbon geo-sequestration (CGS) projects, and the presence of nanoparticles (NPs) after nanofluid-flooding can add more complexity to carbon geo-storage projects. Despite studies investigating CO2 injection and nanofluid-flooding for EOR projects, no information was reported about the potential synergistic effects of CO2 and NPs on enhanced oil recovery (EOR) and CGS concerning the interfacial tension (γ) of CO2-oil system. This study thus extensively inves

Due to its high energy density and near-isothermal storage capability, phase change materials (PCMs) can play a pivotal role in mitigating the temporal mismatch between energy supply and demand in solar thermal systems. The present research addresses the interplay between PCM behavior and fluid flow conditions through comprehensive experimental investigation of two systems of PCM-based thermal collectors throughout charging, melting, and discharging eras. Both systems use paraffin wax as PCM, one with a melting temperature of 38 °C, and the other with 50 °C. The two systems were designed, manufactured, and tested simultaneously in same real outdoor conditions under four water flow rates covering laminar and turbulent regimes. It is found

All alive languages had passed linguistic changes that made the mother language not recognized by its present speakers. Some of these changes are: syntactical, semantical, orthographical, phonetical and lexical.During the period of changes which extends over centuries, there had been a lof of written texts, such as literately texts, biographies, personal memories and manuscripts which are conserved until now as a literatel, historic and linguistic testimonies.Spanish is one of these languages that had been changed, so, the poem of the Cid (1145) was written in a Spanish which differs from the Spanish in which Cervantes wrote the Don Quixote in (1605/1615) and the Spanish of both of them differs from the Spanish of Francisco Ayala and Azorin

En el contexto de la disponibilidad léxica, Esta investigación surge de la necesidad de enseñar, a los estudiantes extranjeros de comunicación que cursan sus estudios en nuestra universidad, el español especializado que realmente necesitan. La metodología disponibilidad léxica ofrece una oportunidad en cuanto a la elaboración de los manuales.

Abstract

This article presents the lexical availability as a practical tool, this research can be exploited didactically in the teaching of vocabulary as a foreign languages LE.

El presente trabajo es un estudio sintáctico y práctico en que se trata de explicar el funcionamiento de "ya" en la oración, el objetivo principal de este estudio es el análisis del complejo significado de "ya" teniendo en cuenta el modo de la acción del verbo sobre el que incide semánticamente el adverbio.

   En este estudio empírico aclaramos los distintos valores de "ya" e intentamos demostrar que es un adverbio que significa una determinada modalidad del enunciado.

   Pero antes de explicar detalladamente nuestro estudio presentaremos un resumen del adverbio en general , porque "ya" es uno de los adverbios de tiempo , este p