Quantitative corrosion imaging of pipelines using multi helical guided ultrasonic waves

Dehghan-Niri, Ehsan,Salamone, Salvatore Techno-Press 2016 Structural monitoring and maintenance Vol.3 No.3

This paper presents a multi helical ultrasonic imaging approach for quantitative corrosion damage monitoring of cylindrical structures. The approach consists of two stages. First a multi helical ultrasonic imaging (MHUI) algorithm is used to provide qualitative images of the structure of interest. Then, an optimization problem is solved in order to obtain quantitative damage information, such as thickness map. Experimental tests are carried out on a steel pipe instrumented with six piezoelectric transducers to validate the proposed approach. Three thickness recesses are considered to simulate corrosion damage. The results show the efficiency of the proposed approach for quantifying corrosion location, area and remnant thickness.

Current-Type Nine-Switch Inverters

Dehghan, Seyed Mohammad,Mohamadian, Mustafa,Yazdian, Ali The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.2

In this paper two dual output current-type inverters are proposed. These inverters have been called a current source nines-witch inverter and a current-type z-source nine-switch inverter by the authors. The proposed inverters have two independent current source outputs. Compared to two independent current source inverters, the proposed converters are implemented with fewer semiconductor switches. Space vector modulation (SVM) is proposed for these converters. Simulation results show the validity and performance of the proposed inverters.

ON THE REFLEXIVE SOLUTIONS OF THE MATRIX EQUATION AXB + CYD = E

Dehghan, Mehdi,Hajarian, Masoud Korean Mathematical Society 2009 대한수학회보 Vol.46 No.3

A matrix $P{\in}\mathbb{C}^{n{\times}n}$ is called a generalized reflection matrix if $P^*$ = P and $P^2$ = I. An $n{\times}n$ complex matrix A is said to be a reflexive (anti-reflexive) matrix with respect to the generalized reflection matrix P if A = PAP (A = -PAP). It is well-known that the reflexive and anti-reflexive matrices with respect to the generalized reflection matrix P have many special properties and widely used in engineering and scientific computations. In this paper, we give new necessary and sufficient conditions for the existence of the reflexive (anti-reflexive) solutions to the linear matrix equation AXB + CY D = E and derive representation of the general reflexive (anti-reflexive) solutions to this matrix equation. By using the obtained results, we investigate the reflexive (anti-reflexive) solutions of some special cases of this matrix equation.

Green Synthesis of ZnO/αFe2O3 Nano-photocatalyst for Efficient Removal of Carbamate Pesticides in Wastewater: Optimization, Mineralization, and Financial Analysis

Dehghan Ali,Aliasghar Arash,Rahmati Roxana,Delnavaz Mohammad,Khoshvaght Hoda 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.1

As emerging organic agricultural pollutants, carbamate pesticides can react with other contaminants in aquatic environments to produce new toxic compounds threatening aquatic life and ecosystems. This study introduces a novel, nonhazardous, and greener method to synthesize a cross-linked ZnO/αFe 2 O 3 nano-photocatalyst to treat carbamate pesticides via ball milling. ZnO/αFe 2 O 3 was characterized through various methods, including XRD, EDX, XRF, DRS, BET, FE-SEM, PL, and FTIR analyses. Using the Response Surface Methodology (RSM), the ability of ZnO/αFe 2 O 3 nano-photocatalyst to remove carbamate from synthesized wastewater was assessed. The BET result indicated a decrease in the diameter of the nanocomposite size after the synthesis. At the same time, the BET surface area and total pores increased from 4.9871 m 2 .g −1 and 0.02806 cm 3 .g −1 to 6.8524 m 2 .g −1 and 0.069497 cm 3 .g −1 , respectively. In addition, the band-gap energy decreased from 3.179 eV for ZnO to 1.907 eV for ZnO/αFe 2 O 3 and eventually reached 1.878 eV for heat-treated ZnO/αFe 2 O 3 nanocomposite. The catalyst concentrations used in the experiments were 0.5, 1, and 1.5 g/L. The solution pH was set to 5, 8, and 11, and three diff erent residence times of 1, 2, and 3 h were used. The model’s results indicated a strong agreement between the experimental and predicted data (R 2 = 0.99). When the nanocomposite’s concentration, pH, and retention time were set at 1 g/L ZnO/αFe 2 O 3 , 8.51, and 3 h respectively, the optimized conditions predicted a removal effi ciency of 89%. In addition, the cost of COD removal was reduced by 50% using ball milling and heat-treatment synthesis. The photocatalyst’s reusability was tested in three stages, and the outcomes demonstrated its stability throughout these three stages.

The TP53 intron 6 G13964C Polymorphism and Risk of Thyroid and Breast Cancer Development in the Iranian Azeri Population

Dehghan, Roghayeh,Feizi, Mohammad Ali Hosseinpour,Pouladi, Nasser,Adampourezare, Mina,Farajzadeh, Davoud Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.7

Background: TP53 mutations are the most common genetic alterations in human cancers. There are also several polymorphisms in both exons and introns of TP53 that may influence its anti-tumor functions and increase the risk of cancer development. Associations of the TP53 intron 6 G13964C polymorphism with increased risk of development of several cancers have been investigated in numerous studies, but the results were controversial and conflicting. In this study, we aimed to investigate the probable association of this polymorphism with risk of both thyroid and breast cancers among the Iranian-Azeri population. Materials and Methods: We performed two separate case control studies on associations of the intron 6 polymorphism with two different kinds of cancer. In one case-control study, a total of 75 patients with thyroid carcinoma and 180 controls were analyzed and the other study included 170 patients with breast cancer and 135 healthy women. The intron 6 genotype was determined by RFLP-PCR and the SPSS 16 program was applied for data analysis. Results: For thyroid cancer, the frequencies of GG genotype were 96.0% in patients and 93.3% in controls. The GC genotype had a frequency of 4.0 % in patients and 6.7% in controls. In the study on breast cancer, the frequency of GG and GC genotypes in patients were 95.3% and 4.7%, respectively. In breast related control group, the frequency of GG genotype was 93.3 % and the frequency of GC genotype was 6.7%. None of the cases and controls had the CC genotype. Conclusions: There was no significant association between the TP53 intron 6 G13964C polymorphism and risk of development of both thyroid and breast cancer in Iranian-Azeri patients.

Isolation, Characterization, and Investigation of Surface and Hemolytic Activities of a Lipopeptide Biosurfactant Produced by Bacillus subtilis ATCC 6633

Dehghan-Noudeh Gholamreza,Housaindokht Mohammadreza,Bazzaz Bibi Sedigeh Fazly The Microbiological Society of Korea 2005 The journal of microbiology Vol.43 No.3

Bacillus subtilis ATCC 6633 was grown in BHIB medium supplemented with $Mn^{2+}$ for 96 h at $37^{\circ}C$ in a shaker incubator. After removing the microbial biomass, a lipopeptide biosurfactant was extracted from the supernatant. Its structure was established by chemical and spectroscopy methods. The structure was confirmed by physical properties, such as Hydrophile-Lipophile Balance (HLB), surface activity and erythrocyte hemolytic capacity. The critical micelle concentration (cmc) and erythrocyte hemolytic capacity of the biosurfactant were compared to those of surfactants such as SDS, BC (benzalkonium chloride), TTAB (tetradecyltrimethylammonium bromide) and HTAB (hexadecyltrimethylammonium bromide). The maximum hemolytic effect for all surfactants mentioned was observed at concentrations above cmc. The maximum hemolytic effect of synthetic surfactants was more than that of the biosurfactant produced by B. subtilis ATCC 6633. Therefore, biosurfactant would be considered a suitable surface-active agent due to low toxicity to the membrane.

Improvement of Seed Quality of Wheat (Triticum aestivum) as Affected by Brassinolide under Different Irrigation Regimes

Marzieh Dehghan,Hamidreza Balouchi,Alireza Yadavi 한국작물학회 2020 Journal of crop science and biotechnology Vol.23 No.2

Irrigation interruption owing to time of incidence is affecting the seed quality. The aim of this research was to determine whether the brassinolide and spraying time of this hormone in two stages of applying irrigation interruption could be improved the quality of produced grain wheat during 2014-2016. Irrigation regimes were carried out at irrigation interruption from the flowering and grain-filling stage and full irrigation as a control. The second factor was including factorial of zero, 0.05, and 0.1 mg l-1of brassinolide and spraying time before the flowering and grain-filling stages. The maximum grain weight had no significant difference between the both irrigation interruptions. The lowest period and the highest rate of grain filling were observed after irrigation interruption in the flowering stage. The seed germination and vigor index of seedlings were increased in irrigation interruption at the flowering stage and without the spraying of hormones. The foliar application of 0.1 mg l-1 brassinolide caused the highest seedling vigor index and the lowest electrolyte leakage from grain. Overall, the application of 0.1 mg l-1 brassinolide improved the quality of wheat seed affected by the irrigation interruption at the flowering and grain-filling stages in water restriction.

On the Cultural Schema and Iranian EFL Learners` Reading Performance: A Case of Local and Global Items

( Farzaneh Dehghan ),( Firooz Sadighi ) 범태평양응용언어학회 2011 범태평양응용언어학회지 Vol.15 No.2

Reading skill has taken on an important role in most EFL teaching situations. While linguistic knowledge is only one aspect of this skill, background knowledge including culture can also play an important role (Alptekin, 2006; Johnson, 1981; Pritchard, 1990; Steffensen, Chitra, & Anderson, 1979). This study investigated the effect of cultural background or cultural schema on the performance of Iranian EFL students on local (bottom-up) and global (top-down) processes. Sixty-six female pre-university students took part in the study. They read five texts with familiar cultural themes and five texts with culturally unfamiliar topics (total=10). The multiple-choice items were designed in a way to test both bottom-up processing (word recognition, literal comprehension and finding referents of pronouns) and top-down processing (making inferences, skimming, scanning, etc). The findings showed that our students performed significantly better on local items compared with global items both for (un)familiar texts. It was also observed that their overall performance was mostly influenced by text familiarity. Their higher scores on local items can be explained by the fact that these items are totally easier to process due to the linguistic context available. In contrast, the difficulty of the global items can be explained because our EFL learners need extra linguistic knowledge to process such items. Also, this difference could be attributed to the teaching situation in which language teachers do not teach students how to read at all and learners are not familiar with higher-level, global processes being important in reading comprehension.

Nonlinear Simulator model Identification of a Walking Beam Furnace Using Recurrent Local Linear Neuro-Fuzzy Network

Hamed Dehghan Banadaki,Hassan Abbasi Nozari,Hossein Kakahaji 보안공학연구지원센터(IJCA) 2011 International Journal of Control and Automation Vol.4 No.4

Morphology study of nanofibers produced by extraction from polymer blend fibers using image processing

Neda Dehghan,Mohammad Ali Tavanaie,Pedram Payvandy 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.9

The morphology of nanofibers extracted from the industrial-scale produced polypropylene/polybutylene terephthalate (PP/PBT) blend fibers was studied. To study the morphology and diameter measurements of the nanofibers, image processing method was used, and the results were compared with the results of a conventional visual method. Comparing these two methods indicated the good performance of image processing methods for the measuring of nanofiber diameter. Among the various applied image processing methods, the fuzzy c-means (FCM) method was determined as the best for image thresholding. Additionally, the distance transform method was determined as the best way for measuring nanofiber diameter. According to high regression coefficient (R=0.98) resulting between the draw ratio and nanofibers diameter, the high effectiveness of draw ratio to nanofiber diameter is concluded. The spherical (drop) shapes of the PBT dispersed phase particles were eventually deformed into very thin fibrils during the drawing process. The results of measuring the nanofiber diameters showed that the diameter means of nanofibers varied from 420 nm to 175 nm with the highest draw ratio. Good uniformity for diameter of nanofibers was observed, which had not been observed in previous works.