s. kashian

Value Engineering (VE) enables project managers to discover the size and location of problems in a project and to mitigate any potential backwardness. The current research aimed to find major impressive criteria and to measure their impact level on promoting the value of large-scale/mega projects using VE concepts. The hindrance and obstacles available in the application of VE in construction engineering were considered to ensure the accuracy. The main research objective was to forecast the effect of quality, cost, and time factors on the project value using an adaptive neuro fuzzy inference system (ANFIS) model. To create the ANFIS model, the required data were collected through a five-point scale Likert questionnaire, by which the expert opinions were obtained, and pairwise comparisons of the items were accomplished. The model was created using MATLAB. The statistical population was adopted from the experts and managers working in a large-scale project who were familiar with the concepts and details of VE and project management. According to the literature, more than 50 VE criteria were found, which were then reduced to 25 criteria based on experts’ opinions. These final criteria were categorized into three groups: cost, time, and quality. Afterwards, the data collected via the questionnaires were analyzed by the ANFIS model. Before completing the calculations, validity and reliability of the analytical model were investigated to ensure that the results are both valid and reliable enough for further use. The results showed that the criterion entitled ‘proper programming …’ had the highest impact on promoting the projects value, while the criterion entitled ‘prevention of work and responsibility interference …’ had the least influence. Both of the mentioned criteria were situated in the group of cost, indicating the higher importance of this group than that of the other groups.

Considering the importance of quality control of radiotherapy systems and 3D dose mapping possibility done with a Fricke agarose gel dosimeter, this dosimeter based on ferrous solution and agarose gel was prepared. The prepared Fricke gel dosimeters was investigated under gamma irradiation with a dose range up to 20 Gy. Concerning the effect of the gel dosimeter constituent’s concentration on the response of the dosimeter, different compositions were surveyed for better sensitivity and repeatability. So, the responses were evaluated for different concentrations of ferrous ion, sulphuric acid, and the indicator. We found that the Fricke agarose gel dosimeter has a linear behavior up to 20 Gy. In addition, the best composition of Fricke agarose gel dosimeter with high sensitivity and stability was determined to be 0.2 mM ferrous, 25 mM sulphuric acid, and 0.15 mM Xylenol orange.

Fast neutron flux (14.8 MeV) of a neutron generator has been measured by activation technique. The measurements performed using Cu and Ni threshold detectors. 62Cu and 57Ni were produced through 63Cu (n, 2n) 62Cu and 58Ni (n, 2n)57Ni reactions. They decay by emitting 511 keV and 1377 keV gamma rays, respectively. The half life of 62Cu is 9.74min and that of 57 Ni is 36 hours. The flux of neutron has been calculated by measuring the activity after the irradiation time. Gamma spectroscopy of the activated foils was performed using a HPGe detector. By employing this technique the neutron flux of 2.64×107±3%n/s was obtained for 60 μΑ deuteron of 110 keV energy, bombarding a solid target of 3H.