A Reliability-based Methodology for Considering Corrosion Effects on Fatigue Deterioration in Steel Bridges - Part I: Methodology -

Abdollah Hosseini,Ali Sahrapeyma,Mohammad S. Marefat 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.4

It is known that the effects of corrosion on fatigue originate from two major sources: stress concentration due to corrosiondiscontinuities (CNF factor) and stress amplification due to loosing net section (NAF factor). In order to account for theseeffects, a performance function is developed which takes CNF and NAF factors into account and considers both random andtime-dependent nature of the involved parameters. In order to consider real fatigue and environmental conditions, the availableCNF-y and y-t functions are extended employing α and ϕ factors, respectively. In addition, some recommendations have beenmade to establish corrosion pattern of different steel sections. The final output of the methodology is development of areliability-based procedure to establish time-dependent deterioration profile of a structural member, which assists in decisionmakingwith regard to maintenance activities. The proposed methodology has been applied to Neka Bridge, a railway bridgein northern Iran, which is presented in Part II.

Determination of defect depth in industrial radiography imaging using MCNP code and SuperMC software

Khorshidi Abdollah,Khosrowpour Behzad,Hosseini S. Hamed 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7

Background: Non-destructive evaluation of defects in metals or composites specimens is a regular method in radiographic imaging. The maintenance examination of metallic structures is a relatively difficult effort that requires robust techniques for use in industrial environments. Methods: In this research, iron plate, lead marker and tungsten defect with a 0.1 cm radius in spherical shape were separately simulated by MCNP code and SuperMC software. By 192Ir radiation source, two exposures were considered to determine the depth of the actual defined defect in the software. Also by the code, displacement shift of the defect were computed derived from changing the source location along the x- or y-axis. Results: The computed defect depth was identified 0.71 cm in comparison to the actual one with accuracy of 13%. Meanwhile, the defect position was recognized by disorder and reduction in obtained gamma flux. The flux amount along the x-axis was approximately 0.5Eþ11 units greater than the y-axis. Conclusion: This study provides a method for detecting the depth and position of the defect in a particular sample by combining code and software simulators

Prediction of Time-varying Maximum Scour Depth Around Short Abutments using Soft Computing Methodologies - A Comparative Study

Khosrow Hosseini,Hojjat Karami,Hossein Hosseinjanzadeh,Abdollah Ardeshir 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.5

Maximum depth of scouring around bridge abutments is a significant criterion in design of safe depth for abutment foundation. Many studies done on maximum scouring depth are limited to specific shape of abutment and there is no general equation in the estimation of time varying scour depth at short abutments. In this research, maximum depth and also the temporal variation of local scour at a vertical-wall, wing-wall and semicircular abutments, and spur dike as well, were investigated experimentally. About 1400 sets of experimental data were collected. The results indicated that 70-90% of the equilibrium scouring depths occurred during the first 20% of overall time of scouring tests. According to the collected data, Multiple Nonlinear Regression (MNLR), Artificial Neural Networks (ANN) and Adaptive Neuro Fuzzy Inference System (ANFIS) were adopted to predict the time variation of scour depth around abutments. The computer models were compared to the other empirical equations presented in the literature. The study showed that the conducted regression model is rather precise and practical (R2 = 0.88). Also, the results of the numerical modeling indicated that ANFIS model produced the best results (R2 = 0.98) in comparison with ANN models using feed forward back propagation (R2=0.96) and radial basis function (R2 = 0.94).

Local Behavior of Column-tree Connections with Considering Bolt-hole Clearance and Bolt Pretension Effects

Rasoul Gharebaghi,Abdollah Hosseini 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.2

In this paper, effects of bolt-hole clearance and bolt pretension level on seismic performance of column-tree moment resisting frames with reduced beam section have been investigated. In a typical constructional environment, manufacturing tolerances and field situations cause inappropriate positioning of bolts in their corresponding holes in bolted connections, so bolt-hole diameter increases by incorrect methods like acetylene gas cutting method. On the other hand, nonlinear local behavior of the connection elements and effects of dynamic friction during the process of applying the bolt pretension cause wrong evaluation of bolt pretension level. In order to investigate these problems, models of column-tree connections with various bolt-hole clearances and bolt pretension levels subjected to cyclic loading were developed and analyzed with 3D FEM and their hysteresis curves were obtained and evaluated. Results show that bolt-hole clearance can reduce the flexural capacity of column-tree connections especially along with reduction in the bolt pretension level while interstory drift angle increases during inelastic cycles.

Life-cycle Prediction of Steel Bridges using Reliability-based Fatigue Deterioration Profile: Case Study of Neka Bridge

Ali Sahrapeyma,Abdollah Hosseini,Mohammad S. Marefat 한국강구조학회 2013 International Journal of Steel Structures Vol.13 No.2

Fatigue deterioration profiles of critical elements in a railway truss bridge are determined using a probabilistic approach. A performance function including fatigue strength, R, and fatigue action, D, is used, where R is a material property with lognormal distribution. The random variable D depends on AASHTO category, stress spectrum and traffic features. By applying Monte-Carlo simulations on the performance function of each year, reliability index profile is calculated. The reliability profile decreases with life, and whenever reaches to a critical value, an MR&R action should be implemented. A numerical approach is presented to specify the effects of MR&R actions on the deterioration profile. These actions include re-welding, attaching CFRP and combination of them. The structural model is calibrated by results of a loading test. In addition, the uncertainties arisen from future traffic volume and the relevant S-N curve are considered by a statistical analysis. For a target reliability of 2.0, the retrofit time for deck and truss are estimated. Finally, the outputs of the research are used to recommend a plan for maintenance of Neka Bridge.

Impact of Barium in Improving Corrosion Resistance and Properties of Electroless Ni–Ba–B Alloy Deposits

Sareh Rahmani,Abdollah Omrani,Sayed Reza Hosseini 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.7

Electroless Ni–B deposits have found many applications because of their unique properties. To enhance the performance ofNi–B deposit, one can add a third element and accordingly Ni–Ba–B ternary alloy synthesized and characterized for the firsttime. The alloy deposits of Ni–Ba–B on steel substrate are characterized for their chemical composition, microstructures,morphology, and micro-hardness by means of different instrumental techniques. Microstructural examination by FE-SEMindicated that the grains of coatings are in the form of nodule with different microstructures. The XRD experiments confirmedthe simultaneous presence of amorphous and microcrystalline phases in the Ni–Ba–B deposits. Compared to Ni–B deposits,the micro-hardness and corrosion resistance of the ternary deposits are also improved.

Glutathione-responsive hydrogel and molecularly imprinted polymer nanospheres: New aspect on cisplatin delivery

Mohammad Hassan Loghmani,Abdollah Fallah Shojaie,Seyyedeh Azadeh Hosseini 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.96 No.-

In this study, Glutathione-responsive hydrogel, MIPs and their related NIPs were synthesized byprecipitation polymerization method. Effect of HEMA/MAA and EGDMA/TRIM as functional monomerand crosslinking agents on size, morphology, drug loading and releasing were studied. BACy as a disulfidecross-linking agent was used in praparation of Glutathione-responsive hydrogel. The size andmorphology of MIPs and NIPs were examined by FE-SEM technique. Results showed EGDMAsynthesizedMIPs had the smaller size than TRIM-prepared MIPs. In order to measure the capacity of MIPsor NIPs for binding to cisplatin, static and dynamic adsorption experiments were done. The amounts ofcisplatin were measured by HPLC method. The binding capacity of drug by MIPs is observed to be higherthan NIPs. The EGDMA-synthesized polymers showed a high percentage of adsorption. NIPs weresaturated much sooner than MIPs. In vitro release assays of cisplatin were done in PBS at pH = 7.4 andtemperature of 37 C. The results showed that increase of the amount of GSH cause to increase release ofthe drug from hydrogel.

Buckling-restrained brace with CFRP encasing: Mechanical behavior & cyclic response

S. Ali Razavi,Amirhossein Kianmehr,Abdollah Hosseini,S. Rasoul Mirghaderi 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.27 No.6

Buckling-restrained braces (BRBs) have received considerable attention in seismic design of various types of structures. Conventional BRBs are composed of steel core and surrounding steel tube filled with concrete. Eliminating the steel tube can be advantageous to BRB. In this study the idea of replacing the steel tube by CFRP layers in BRBs is proposed. The advantages of this type of BRB are mentioned, and its design criteria are introduced. The construction procedure of two BRB specimens is described. The specimens are uniaxially tested based on moderate, and severe earthquake levels and the performance of the specimens is investigated. The backbone curves resulted from the hysteresis curve are presented for the design proposes. The results of this study show that CFRP layers can effectively provide the expected performance of the encasing, and the proposed BRB can be considered a viable alternative to the conventional BRBs.

Effects of dietary Spirulina on antioxidant status, lipid profile, immune response and performance characteristics of broiler chickens reared under high ambient temperature

Mirzaie, Sara,Zirak-Khattab, Fahim,Hosseini, Seyed Abdollah,Donyaei-Darian, Hamid Asian Australasian Association of Animal Productio 2018 Animal Bioscience Vol.31 No.4

Objective: Spirulina has been recognized formerly as a filamentous spiral-shaped blue- green algae but more recently as a genus of photosynthetic bacteria (Arthrospira). This microorganism is considered as a rich source of essential nutrients for human and animals. The present study was conducted to determine potential application of Spirulina for heat- exposed broilers. Methods: Two hundred and fifty Cobb 500 chicks with male to female in equal ratio with average initial weight of 615.6 g at 17 days of age were divided into 5 treatments with 5 replicates of 10 chicks. Treatment groups were as follows: positive and negative controls with 0% Spirulina supplement and three Spirulina receiving groups with 5 g/kg (0.5%), 10 g/kg (1%), and 20 g/kg (2%) supplementation. Spirulina receiving groups as well as positive control were exposed to high ambient temperature at $36^{\circ}C$ for 6 h/d from 38 to 44 days of age. Biochemical variables were measured in serum samples at 35, 38, 42, and 45 days of broiler chickens age. Results: The results showed that supplementation of the diet with Spirulina decreased concentration of stress hormone and some serum lipid parameters while enhanced humoral immunity response and elevated antioxidant status whereas it didn't meaningfully affect performance characteristics. Nevertheless, feed conversion ratio was improved numerically but not statistically in broilers fed with 1% Spirulina under high ambient temperature. Conclusion: Overall, the present study suggests that alleviation of adverse impacts due to high ambient temperature at biochemical level including impaired enzymatic antioxidant system, elevated stress hormone and lipid profile can be approached in broiler chickens through supplementation of the diet with Spirulina platensis.

Copro-molecular diagnosis of the Toxoplasmatinae subfamily in dog and cat populations in northern Iran

Leila Izadi,Shahabeddin Sarvi,Seyed Abdollah Hosseini,Afsaneh Amouei,Mehdi Sharif,Mohammad Taghi Rahimi,Tooran Nayeri,Ahmad Daryani 한국역학회 2020 Epidemiology and Health Vol.42 No.-

OBJECTIVES: The oocysts of the Toxoplasmatinae subfamily (Neospora caninum, Hammondia hammondi and H. heydorni, and Besnoitia besnoiti) are morphologically similar to Toxoplasma gondii, and indistinguishable from each other. This study investigated the prevalence of the Toxoplasmatinae subfamily in dog and cat fecal samples using a nested polymerase chain reaction method. METHODS: Overall, 200 fecal samples from domestic dogs (n=120) and cats (n=80) were collected from 15 farms in northern Iran. The samples were homogenized in 2.5% potassium dichromate solution and subsequently concentrated with sucrose solution. DNA was extracted from samples using a genomic DNA kit. Specific primers and the 18S rDNA gene were used to screen and detect all Toxoplasmatinae oocysts. RESULTS: Overall, 2.5% (3 of 120) and 22.5% (18 of 80) of the fecal samples collected from dogs and cats were infected with Toxoplasmatinae. In dogs, 2 samples were positive for N. caninum and 1 sample was positive for T. gondii. In cats, all 18 positive samples belonged to T. gondii. No contamination with H. heydorni was observed in dog fecal samples or H. hammondi and B. besnoiti in cat fecal samples. A phylogenetic analysis revealed that the T. gondii (cat) and N. caninum (dog) found had similarities with parasites reported from other regions of the world. CONCLUSIONS: This is the first study to provide data on the epidemiology of Toxoplasmatinae oocysts in Iran. The findings suggest that public-health monitoring for the effective control of feces from cats and dogs and improved pet hygiene habits are needed.