Precise Void Fraction Measurement in Two-phase Flows Independent of the Flow Regime Using Gamma-ray Attenuation

Nazemi, E.,Feghhi, S.A.H.,Roshani, G.H.,Gholipour Peyvandi, R.,Setayeshi, S. Korean Nuclear Society 2016 Nuclear Engineering and Technology Vol.48 No.1

Void fraction is an important parameter in the oil industry. This quantity is necessary for volume rate measurement in multiphase flows. In this study, the void fraction percentage was estimated precisely, independent of the flow regime in gas-liquid two-phase flows by using ${\gamma}-ray$ attenuation and a multilayer perceptron neural network. In all previous studies that implemented a multibeam ${\gamma}-ray$ attenuation technique to determine void fraction independent of the flow regime in two-phase flows, three or more detectors were used while in this study just two NaI detectors were used. Using fewer detectors is of advantage in industrial nuclear gauges because of reduced expense and improved simplicity. In this work, an artificial neural network is also implemented to predict the void fraction percentage independent of the flow regime. To do this, a multilayer perceptron neural network is used for developing the artificial neural network model in MATLAB. The required data for training and testing the network in three different regimes (annular, stratified, and bubbly) were obtained using an experimental setup. Using the technique developed in this work, void fraction percentages were predicted with mean relative error of <1.4%.

EXPERIMENTAL AND COMPUTATIONAL INVESTIGATION OF DIESEL AND GASOLINE INJECTION IN A DIRECT INJECTION COMPRESSION IGNITION ENGINE

Mohammad Nazemi Babadi,Saeid Kheradmand,배충식 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.1

In this paper, the numerical simulation of the diesel and gasoline fuels injection in a constant volume chamber and in a cylinder under the operating conditions of a compression ignition (CI) engine is conducted. The simulation results are compared with the experimental data which derived from fast imaging techniques. In order to check out the possibility of using gasoline instead of diesel to increase the volumetric efficiency of the CI engine, the spray characteristics of the gasoline and diesel with injection pressures of 40 and 80 MPa, as well as temperatures of 243, 273 and 313 K, under cold start condition is investigated. The results show that under the same conditions, the vapor penetration length for the two fuels is approximately equal and due to the lower volatility of the diesel fuel, its liquid penetration length in 40 and 80 MPa injection pressures was found to be 7 and 9 mm higher than gasoline, respectively. In addition, the reduction in fuel temperature from 313 K to 243 K leads an increase in the penetration of gasoline and diesel liquids by 12 and 10 mm, respectively. Finally, the decrease in the evaporation rate causes a non-homogeneous mixture and results an increase in the unburned hydrocarbons and emissions.

Practical Segmentation Methods for Logical and Geometric Layout Analysis to Improve Scanned PDF Accessibility to Vision Impaired

Azadeh Nazemi,Iain Murray,David A. Mc Meekin 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.4

Precise Void Fraction Measurement in Two-phase Flows Independent of the Flow Regime Using Gamma-ray Attenuation

E. Nazemi,S.A.H. FEGHHI,G.H. Roshani,R. Gholipour Peyvandi,S. Setayeshi 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.1

Void fraction is an important parameter in the oil industry. This quantity is necessary forvolume rate measurement in multiphase flows. In this study, the void fraction percentagewas estimated precisely, independent of the flow regime in gaseliquid two-phase flows byusing g-ray attenuation and a multilayer perceptron neural network. In all previous studiesthat implemented a multibeam g-ray attenuation technique to determine void fractionindependent of the flow regime in two-phase flows, three or more detectors were usedwhile in this study just two NaI detectors were used. Using fewer detectors is of advantagein industrial nuclear gauges because of reduced expense and improved simplicity. In thiswork, an artificial neural network is also implemented to predict the void fraction percentageindependent of the flow regime. To do this, a multilayer perceptron neuralnetwork is used for developing the artificial neural network model in MATLAB. Therequired data for training and testing the network in three different regimes (annular,stratified, and bubbly) were obtained using an experimental setup. Using the techniquedeveloped in this work, void fraction percentages were predicted with mean relative errorof <1.4%.

A Prospective Pilot Study Investigating Performance of 18F-Fluciclovine PET Imaging for Detection of Prostate Cancer 2 Years Following Primary Partial Gland Cryoablation

Azadeh Nazemi,William C. Huang,James Wysock,Samir S. Taneja,Kent Friedman,Rozalba Gogaj,Herbert Lepor 대한핵의학회 2022 핵의학 분자영상 Vol.56 No.4

Purpose The goal of partial gland ablation (PGA) is to eradicate focal lesions of clinically significant prostate cancer (csPCa) with minimal adverse impact on functional outcomes. The primary objective of this study is to characterize the performance of 18F-Fluciclovine PET imaging for detection of prostate cancer following PGA. Materials and Methods Subjects 2 years following primary partial gland cryoablation (PPGCA) were invited to participate in an IRB-approved study providing they met the following inclusion criteria: a single reported mpMRI region of interest (ROI) concordant with biopsy Gleason Grade Group (GGG) < 4, no gross extra-prostatic extension on mpMRI, and no GGG > 1 or GGG 1 with a core length > 6 mm on contralateral systematic biopsy. 18F-Fluciclovine PET MRI imaging of the prostate was performed followed by in and out-of-field biopsies. Results Twenty-seven men who met eligibility criteria participated in the prospective study. In-field and out-of-field csPCa recurrence rate was 7.4% and 22.2%, respectively. The sensitivity and positive predictive value of mpMRI and PET imaging did not reach performance to reliably inform who should undergo prostate biopsy. Conclusion At 2 years following PPGCA, the rate of in-field csPCa was exceedingly low indicating a limited role for imaging to inform in-field biopsy decisions. The csPCa detection rate of out-of-field recurrence was 22% which provides an opportunity for imaging to inform out-of-field biopsy decisions. Based on our findings, 18F-Fluciclovine PET MRI cannot be used to inform who should undergo out-of-field prostate biopsy at 2 years following PPGCA.

Proposing a gamma radiation based intelligent system for simultaneous analyzing and detecting type and amount of petroleum by-products

Roshani, Mohammadmehdi,Phan, Giang,Faraj, Rezhna Hassan,Phan, Nhut-Huan,Roshani, Gholam Hossein,Nazemi, Behrooz,Corniani, Enrico,Nazemi, Ehsan Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.4

It is important for operators of poly-pipelines in petroleum industry to continuously monitor characteristics of transferred fluid such as its type and amount. To achieve this aim, in this study a dual energy gamma attenuation technique in combination with artificial neural network (ANN) is proposed to simultaneously determine type and amount of four different petroleum by-products. The detection system is composed of a dual energy gamma source, including americium-241 and barium-133 radioisotopes, and one 2.54 cm × 2.54 cm sodium iodide detector for recording the transmitted photons. Two signals recorded in transmission detector, namely the counts under photo peak of Americium-241 with energy of 59.5 keV and the counts under photo peak of Barium-133 with energy of 356 keV, were applied to the ANN as the two inputs and volume percentages of petroleum by-products were assigned as the outputs.

A NEW APPROACH FOR ASYMPTOTIC STABILITY A SYSTEM OF THE NONLINEAR ORDINARY DIFFERENTIAL EQUATIONS

Effati, Sohrab,Nazemi, Ali Reza 한국전산응용수학회 2007 Journal of applied mathematics & informatics Vol.25 No.1

In this paper, we use measure theory for considering asymptotically stable of an autonomous system [1] of first order nonlinear ordinary differential equations(ODE's). First, we define a nonlinear infinite-horizon optimal control problem related to the ODE. Then, by a suitable change of variable, we transform the problem to a finite-horizon nonlinear optimal control problem. Then, the problem is modified into one consisting of the minimization of a linear functional over a set of positive Radon measures. The optimal measure is approximated by a finite combination of atomic measures and the problem converted to a finite-dimensional linear programming problem. The solution to this linear programming problem is used to find a piecewise-constant control, and by using the approximated control signals, we obtain the approximate trajectories and the error functional related to it. Finally the approximated trajectories and error functional is used to for considering asymptotically stable of the original problem.

Discrimination of Iranian honeybee populations (Apis mellifera meda) from commercial subspecies of Apis mellifera L. using morphometric and genetic methods

Salehi Shahoo,Nazemi-Rafie Javad 한국응용곤충학회 2020 Journal of Asia-Pacific Entomology Vol.23 No.2

The morphological characters of honeybees have an important role for discriminating honeybee subspecies. In the present research, Iranian populations of honeybee (Apis mellifera) were collected from 19 areas in Iran. The samples were collected from stationary beekeeping sites. Moreover, pictures of honeybee forewings held in the Bee Data Bank in Oberursel were compared with Iranian honeybee populations. 19 morphological characters were measured for each forewing of worker honeybee to evaluate differentiation of Iranian honeybee populations from the commercial honeybee subspecies A. m. mellifera, A. m. carnica, A. m. caucasica and A. m. ligustica. Additionally, part of the tRNAleu gene, an intergenic region and part of COII was used to confirm differentiation of the commercial subspecies from Iranian honeybee populations. Results of the cluster analyses showed that 19 morphological characters of forewings differentiated Iranian populations from the commercial subspecies. Moreover, the phylogenetic tree of part of the tRNAleu gene, an intergenic region and part of COII differentiated the commercial subspecies from Iranian honeybee populations. Results of the discriminant function analyses (DFA) indicated that the references samples of A. m. meda overlapped with Iranian populations.

Evaluation of the efficacy of mitochondrial ATP 6 and 8, Cyt b and 16S rDNA genes for differentiation of Iranian honeybees (Apis mellifera meda) from commercial subspecies of Apis mellifera L. and comparison with geometric morphometric method

Khoshraftar Mahin,Nazemi-Rafie Javad,Ghobari Hamed 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

Mitochondrial DNA sequence variations and the geometric morphometric method can be used to differentiate honeybee subspecies and evolutionary lineages. Molecular markers are powerful tools for discriminating hon eybee subspecies. In this study, 19 beekeeping sites were selected to collect Iranian honeybee samples. The honeybee forewing images stored at Oberursel (the Bee Data Bank) were used to compare with those of Iranian honeybees using the geometric morphometric method. Furthermore, the abilities of DNA markers to differentiate Iranian honeybees (A. m. meda) from the most common commercial subspecies (A. m. carnica and A. m. ligustica) were assessed. In the present research, 16S rDNA (Mitochondrial 16S rDNA Region) showed greater ability in differentiating Iranian honeybees from other subspecies compared with ATP 6 and 8 and Cyt b. The phylogenetic tree derived from 16S rDNA differentiated A. m. carnica and A. m. ligustica from Iranian honeybees. Principle component analysis (PCA) discriminated C lineage and Z subgroup from A and M lineages using 16S rDNA. In addition, the phylogenetic tree of the 16S rDNA affirmed the findings of the cluster analysis derived from the geometric morphometric method in differentiating A. m. carnica and A. m. ligustica from Iranian honeybees. The cluster analysis grouped reference subspecies of A. m. meda with Iranian honeybees. Moreover, the Discriminant Function Analyses (DFA) differentiated Iranian honeybees from A. m. ligustica and A. m. carnica.

Patient Accounting Systems: Are They Fit with the Users’ Requirements?

Haleh Ayatollahi,Zahra Nazemi,Hamid Haghani 대한의료정보학회 2016 Healthcare Informatics Research Vol.22 No.1

Objectives: A patient accounting system is a subsystem of a hospital information system. This system like other informationsystems should be carefully designed to be able to meet users’ requirements. The main aim of this research was to investigateusers’ requirements and to determine whether current patient accounting systems meet users’ needs or not. Methods: Thiswas a survey study, and the participants were the users of six patient accounting systems used in 24 teaching hospitals. Astratified sampling method was used to select the participants (n = 216). The research instruments were a questionnaire and a checklist. The mean value of ≥3 showed the importance of each data element and the capability of the system. Results: Generally, the findings showed that the current patient accounting systems had some weaknesses and were able to meet between 70% and 80% of users’ requirements. Conclusions: The current patient accounting systems need to be improved to be able to meet users’ requirements. This approach can also help to provide hospitals with more usable and reliable financial information.