The present investigation is based on the idea of intensifying the gas-solids contact in a circulating fluidized bed by introducing obstacles into it. Such obstacles may effectively suppress radial inhomogeneities in the solids flux and concentration, increase the dynamic solids hold-up, and break up solids clusters. This article (Part I) deals with the hydrodynamics (pressure drop and solids h...

AIM To determine any variation in the respiratory responses to hypoxia/hypercapnia of infants born small for gestational age (SGA) to smoking and to non-smoking mothers. METHODS A total of 70 average for gestational age (AGA) infants (>36 weeks gestation, >2500 g, >25th centile for gestational age, and no maternal smoking), and 47 SGA infants (<10th centile for gestational age) were studied a...

The accurate calculation of temperature distribution in key parts of a nuclear plant plays a crucial role in maximising the power output and the plant efficiency, whilst ensuring safe operation. The need for making the most profitable use of the available sources of energy requires the full exploitation of plant operational capacity. Temperature dependent material properties mean that increasin...

objective: the aim of this study is to evaluate the effect of tissue composition on dose distribution in electron beam radiotherapy. methods : a siemens primus linear accelerator and a phantom were simulated using mcnpx monte carlo code. in a homogeneous cylindrical phantom, six types of soft tissue and three types of tissue-equivalent materials were investigated. the tissues included muscle (s...

background: the compositions of ferrous sulphate, agarose and xylenol orange dye (fax) and ferrous sulphate, gelatin and xylenol orange dye (fgx) in solution of distilled water and sulphuric acid are two tissue-equivalent gel dosimeters. ionizing radiation causes oxidation of fe2+ ion to fe3+ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours af...

Introduction: In recent years, the number of complex coronary angiography (CA) is increasing rapidly. These procedures have a significant contribution to medical exposure to the general population. Exposure of patients to high doses of x-rays could cause deterministic effects on the skin. Therefore, the assessment of radiation doses of patients is of great importance. ...

This paper investigate the possibility and effectiveness of multi-mode vibration control of a plate through real-time FPGA (Field Programmable Gate Array) implementation. This type of embedded system offers true parallel and high throughput computation abilities. The control object is an aluminum panel, clamped to a Perspex box’s upper side. Two types of control laws are studied. The first belo...

Introduction: The purpose of this work was to study the ability of MRI normoxic polymer gel dosimetry for evaluating the dose distribution in HDR brachytherapy of esophagial cancer at Imam Reza brachytherapy center (Mashhad, Iran). Materials and Methods: Initially, 2liters of normoxic gel (MAGIC) was fabricated and then poured into 12 calibration test tubes and placed in a perspex walled phanto...

Background: The magnetic resonance imaging (MRI)-based radiotherapy planning method have been considered in recent years because of the advantages of MRI and the problems of planning with two images modality. The first step in MRI-based radiotherapy is to evaluate magnetic resonance (MR) images geometric distortion. Therefore, the present study aimed to evaluate system related geometric distort...