Effect of Geogrid Reinforcement and Soil Relative Density on Performance and Contact Pressures of Ring Foundations on Sand

Masoud Rezazadeh Anbarani,Saeed Abrishami,Meysam Bayat 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.12

Reinforcing soil beneath foundations is one of the standard methods to improve the foundation performance. However, soil relative density may affect the efficiency of reinforcement. This experimental study has been conducted on a model ring foundation resting on medium, dense, and very dense geogrid-reinforced sand. For this purpose, 17 tests were carried out to evaluate the effect of soil density and reinforcement depth and size on bearing capacity and settlement of the ring foundation and its normal contact pressure distribution. The results show that geogrid-reinforced sand with higher relative densities improves bearing capacity and decreases settlements significantly. It can be shown that implementing a geogrid layer that is equal to the dimensions of the footing is cost-effective. The scale effect analysis has been conducted for the model foundation, sand, and geogrid used in this research. Additionally, normal contact pressure distributions for unreinforced and reinforced sand are presented. Decreasing the depth of reinforcement transforms the form of normal contact pressure distribution from saddle to parabolic.

Using adaptive neuro-fuzzy inference system (ANFIS) for proton exchange membrane fuel cell (PEMFC) performance modeling

S. Rezazadeh,M. Mehrabi,T. Pashaee,I. Mirzaee 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.11

In this paper, an adaptive neuro-fuzzy inference system (ANFIS) is used for modeling proton exchange membrane fuel cell (PEMFC)performance using some numerically investigated and compared with those to experimental results for training and test data. In this way,current density I (A/cm2) is modeled to the variation of pressure at the cathode side PC (atm), voltage V (V), membrane thickness (mm),Anode transfer coefficient αan, relative humidity of inlet fuel RHa and relative humidity of inlet air RHc which are defined as input (design)variables. Then, we divided these data into train and test sections to do modeling. We instructed ANFIS network by 80% of numerical-validated data. 20% of primary data which had been considered for testing the appropriateness of the models was entered ANFIS network models and results were compared by three statistical criterions. Considering the results, it is obvious that our proposed modeling by ANFIS is efficient and valid and it can be expanded for more general states.

Adsorption of crystal violet dye by agricultural rice bran waste: Isotherms, kinetics, modeling and influencing factors

Mojtaba Rezazadeh,Majid Baghdadi,Naser Mehrdadi,Mohammad Ali Abdoli 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.3

In this study, the potential of modified rice bran (MRB) was investigated for the elimination of crystal violet (CV) from plotted effluent. In this regard, rice bran (RB) was modified by chlorosulfonic acid. The results of FTIR, EDX, and SEM analysis showed structural change, an increase in the amount of sulfur, and the formation of a new band (998 and 1,225 ㎝<SUP>-1</SUP>) in MRB, respectively. The impact of different variables such as contact time, MRB dosage, pH, CV concentration, and ions content on removal efficiency was studied by using batch experiments. In addition, response surface methodology was employed to optimize the experiments. The maximum removal efficiency of 97.4% was obtained at the adsorbent dosage of 2 g L<SUP>-1</SUP>, initial CV concentration of 100 ㎎ L<SUP>-1</SUP>, and contact time of 42.75 min. The highest adsorption capacity of 603 ㎎ g-1 was acquired by the Langmuir model. The best description of kinetic data was achieved by the Elovich model. The thermodynamic study of the adsorption indicated an endothermic and spontaneous reaction. MRB could be regenerated by HCl 0.5 ㏖ L<SUP>-1</SUP> and removal efficiency was declined 10 percent after 5 adsorption/desorption cycles. It was concluded that MRB is an operational adsorbent to remove CV from effluents.

Numerical simulation of the wall shear stress distribution in a carotid artery bifurcation

Marzieh Rezazadeh,Ramin Ostadi 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.10

The effect of stenosis for a carotid artery bifurcation with elastic and rigid walls is investigated numerically. In the present study, the blood flow is considered as a laminar pulsatile flow. The effect of fluid-solid interaction is carried out using ANSYS-FLUENT software. The results show that the maximum wall shear stress in the stenosed artery is three times higher than that of a healthy artery. The shear stress gradient in elastic arteries Is lower than in rigid arteries. For rigid artery, the return flow and separation length in the diastolic phase is lower than the systolic phase.

Assessment of Progressive Collapse Behaviour of Moment Frames Strengthened with Knee Elements

Peiman Rezazadeh,Mohammad R. Sheidaii2,Alireza Salmasi 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.2

Knee element can be used in junction of beam and column elements for strengthening steel moment frames against progressive collapse. Two diff erent types of knee elements, namely strong and weak knee elements have been used to strengthen the frames. Strong knee element has been designed in a way that it prevents the occurrence of plastic hinge on knee element before beam element. But in weak knee elements, formation of plastic hinge on knee element will be prior to formation of the plastic hinge on the beam element. The nonlinear static alternate path analysis in accordance with the UFC guideline has been used to determine the resistance of structures against progressive collapse. The results indicate the priority of strong knee elements compared to weak knee elements in strengthening the structure against progressive collapse. Installing strong knee element reduces the eff ective length of beams and columns and changes the direction of fl ow of forces from the beam–column connection to out of the knees area and changes the position for the formation of plastic hinges. Eventually, the installation of strong knee elements will increase stiff ness and structural strength and result in better behaviour against progressive collapse.

Food frequency questionnaires developed and validated in Iran: a systematic review

Arezoo Rezazadeh,Nasrin Omidvar,Katherine L,Tucker 한국역학회 2020 Epidemiology and Health Vol.42 No.-

OBJECTIVES: To systematically review and identify food frequency questionnaires (FFQs) developed for the Iranian population and their validation and reproducibility in order to determine possible research gaps and needs. METHODS: Studies were selected by searching for relevant keywords in the PubMed, Scopus, Science Direct, Google Scholar, SID, and Iranmedex databases, unpublished data, and theses in November 2016 (updated in September 2019). All English-language and Persian-language papers were included. Duplicates, articles with unrelated content, and articles only containing a protocol were excluded. The FFQs were categorized based on: (1) number of food items in to short (≤80 items) and long (>80 items) and; (2) the aim of the FFQ to explore total consumption pattern/nutrients (general) or to detect specific nutrient(s)/food group(s) (specialized). RESULTS: Sixteen reasonably validated questionnaires were identified. However, only 13 presented a reproducibility assessment. Ten FFQs were categorized as general (7 long, 3 short) and 6 as specialized (3 long, 3 short). The correlation coefficients for nutrient intake between dietary records or recalls and FFQs were 0.07-0.82 for long (general: 0.07-0.82 and specialized: 0.26-0.67) and 0.20-0.67 for short (general: 0.24-0.54 and specialized: 0.20-0.42) FFQs. Long FFQs showed higher validity and reproducibility than short FFQs. Reproducibility of FFQs was acceptable (0.32-0.89). The strongest correlations were reported by studies with shorter intervals between FFQs. CONCLUSIONS: FFQs designed for the Iranian population appear to be appropriate tools for dietary assessment. Despite their acceptable reproducibility, their validity for assessing specific nutrients and their applicability for populations other than those they were developed for may be questionable.

Reduction of carbon dioxide by bio-façades for sustainable development of the environment

Hamidreza Rezazadeh,Zahra Salahshoor,Ferial Ahmadi,Farshad Nasrollahi 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.2

Nowadays, air pollution and consequently global warming are the major problems that the earth is faced with. These issues can influence climate change and human health. Building façades can play a significant role in the air quality of the urban environment. Therefore, this study draws upon the ability of nature in controlling carbon dioxide to compare three types of bio-façades (i.e. Water façade, Green façade, and Microalgae façade) and to identify an appropriate one. For this purpose, we analyzed documents and scientific literature qualitatively. Then, we identified the aforementioned types of biological façades and selected the most optimal one through the comparison. Additionally, for this comparison, the analytical hierarchy process (AHP) method was employed that resulted in achieving the higher scores by the microalgae façade among other bio-façades mentioned above. The major criteria considered for the AHP analysis included climatic, economic, architectural, environmental, and structural aspects of using the noted bio-façades in buildings. It should be emphasized that the environmental aspect was obtained as the most influential criterion among others. Finally, some technical tips and design requirements for bioreactors are depicted and discussed along with their upcoming challenges and future research direction.

Plasmid-Mediated Quinolone-Resistance (qnr) Genes in Clinical Isolates of Escherichia coli Collected from Several Hospitals of Qazvin and Zanjan Provinces, Iran

Maryam Rezazadeh,Hamid Baghchesaraei,Amir Peymani 질병관리본부 2016 Osong Public Health and Research Persptectives Vol.7 No.5

Objectives: Escherichia coli is regarded as the most important etiological agent of urinary tract infections. Fluoroquinolones are routinely used in the treatment of these infections;however, in recentyears, a growing rate of resistanceto thesedrugs has been reported globally. The aims of this study were to detect plasmid-mediated qnrA, qnrB, and qnrS genes among the quinolone-nonsusceptible E. coli isolates and to investigate their clonal relatedness in Qazvin and Zanjan Provinces, Iran. Methods: A total of 200 clinical isolates of E. coli were collected from hospitalized patients. The bacterial isolates were identified through standard laboratory protocols and further confirmed using API 20E test strips. Antimicrobial susceptibility was determined by the standard disk diffusion method. Polymerase chain reaction (PCR) and sequencing were used for detecting qnrA, qnrB, and qnrS genes and the clonal relatedness of qnr-positive isolates was evaluated by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) method. Results: In total, 136 (68%) isolates were nonsusceptible to quinolone compounds, among which 45 (33.1%) and 71 (52.2%) isolates showed high- and low-level quinolone resistance, respectively. Of the 136 isolates, four (2.9%) isolates were positive for the qnrS1 gene. The results from ERIC-PCR revealed that two (50%) cases of qnr-positive isolates were related genetically. Conclusion: Our study results were indicative of the presence of low frequency of qnr genes among the clinical isolates of E. coli in Qazvin and Zanjan Provinces, which emphasizes the need for establishing tactful policies associated with infection-control measures in our hospital settings.

Use of double-glazed window as a photobioreactor for CO₂ removal from air

Hamidreza Rezazadeh,Maria Kordjamshidi,Ferial Ahmadi,Alireza Eskandarinejad 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.2

The important issue of increasing CO₂ emissions to the atmosphere requires developing the environmentally sustainable strategies. One of the most innovative approaches in building design is using the microalgae photobioreactor (PBR) façades. In the current research, performance of a new green window was examined as an environmentally friendly method for the noted purpose. This window is a double-glazed window wherein the space enclosed by its two glasses was used as a PBR system. This window was investigated in two different conditions, namely as a window installed in a wall opening as a building façade element and also in laboratory condition. The experiments of the former condition were performed in Tehran city, where is known for the greatest air-polluted city in Iran, while tests of the later were carried out in Bablosar city located in northern Iran. Experiments include measuring absorption amounts of CO₂, temperature, optical density of cultivation medium, and evaporation. The obtained results validate performance of the proposed green window in decreasing CO₂ amounts. It was also observed that microalgae growth decreased the window transparency so that, in observing the general rules of Islamic and Iranian architecture, can enhance the visual privacy from non-mahram adjacent neighbors for Muslim women.

An investigation on quilled nozzle-less electrospinning in comparison with conventional methods for producing PAN nanofibers

Sayed Pedram Rezazadeh Tehrani,Mehdi Hadjianfar,Mehran Afrashi,Dariush Semnani 한국의류학회 2018 Fashion and Textiles Vol.5 No.1

Over the last decades by appearing nanotechnology electrospinning has been reconsidered as a significant method. However, electrospinning production rate is limited by the rate at which the polymer solution or melt is fed to a single jet. Feeding rate can be increased through implementing a wide range of methods such as multiple nozzle electrospinning. In the present work, an innovative “quilled” drum with a peculiar design was rotated in a PAN polymer solution in an electrical field to optimize energy consumption, uniform nanofiber distribution on the collector, and increase production rate. The produced nanofibers were compared with those produced from modified multi-nozzle and single-nozzle electrospinning methods. The mean diameters of nanofibers produced from the quilled drum was 32% greater than that of single-nozzle and 28% less than multi-nozzle electrospinning. The CV% of thickness of the webs were 7.9, 11.2, and 12.5% for the quilled, single nozzle and multi-nozzle methods, respectively which showed the presented method produced more uniform webs. The production rate of this electrospinning was 60 and 17 times more than single and multi-nozzle methods, respectively.