tetrahydrobenzo[b]pyran derivatives 1 were utilized for the synthesis of several new pyrano[2,3-d]pyrimidine derivatives 2. compound 2 was obtained in the presence of ac2o/h2so4 (as a catalyst) and was confirmed by spectroscopic data such as ir, 1h nmr and 13c nmr. ab initio calculation was carried out to study geometric optimization, thermodynamic parameters, aromaticity and dynamic process of...

nanocrystalline zno particles were prepared by a novel sonochemical route from zinc acetate and sodium hydroxide without any requirement of calcination steps at high temperature and without surfactants. variations in several parameters and their effects on the structural (crystal size and morphology) properties of nanoparticles were investigated. characterizations were carried out by x-ray diff...

This paper presents a mathematical model that could assist in measuring, monitoring and controlling tem-perature variation in cold and ‘red-hot’ metal working conditions of machining. A numerical analysis tech-nique of the temperature distribution, based on the theory of complex applied potential, was carried out using the principles of relationship analysis between the paths of heat supply in ...

understanding how a cutout influences the load bearing capacity and buckling behavior of cylindrical shells is fundamental in the design of structural components used in automobiles, aircrafts, and marine structures. in this article, simulation and analysis of steel cylindrical shells with various lengths, include quasi elliptical cutout, subjected to axial compression were systematically carri...

this paper presents a mathematical model that could assist in measuring, monitoring and controlling tem-perature variation in cold and ‘red-hot’ metal working conditions of machining. a numerical analysis tech-nique of the temperature distribution, based on the theory of complex applied potential, was carried out using the principles of relationship analysis between the paths of heat supply in ...

Qeshm Channel is a shallow and narrow waterway located between Qeshm Island and the mainland in the vicinity of Hormuzgan Province, Islamic Republic of Iran. This channel is important because of its economic, industrial, fisheries and navigation role it plays as well as environmental issues it presents in the region. A prognostic study was performed to simulate currents in this channel, using C...

The Extracorporeal CO2 removal device (ECCO2RD) is used in clinics to treat patients suffering from respiratory failures like acute respiratory distress syndrome (ARDS) or chronic obstructive pulmonary disease (COPD). The aim of this device is to decarboxylate blood externally with low blood flow. A mathematical model is proposed to describe protective ventilation, ARDS and an extracorporeal CO...

  Background and Objective: According to the fact that neonatal infection is a challenging diagnosis field, several studies have tried to test sensitivity and specificity of diagnostic tests. This study was conducted to evaluate the sensitivity and specificity of procalcitonin (PCT) as a single early marker of neonatal sepsis. Materials and Methods: In this study, 150 neonates admitted to NIC...