Experimental and statistical analysis of hybrid-fiber-reinforced recycled aggregate concrete

Behzad Tahmouresi,Mahdi Koushkbaghi,Maryam Monazami,Mahdi Taleb Abbasi,Parisa Nemati 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.24 No.3

Although concrete is the most widely used construction material, its deficiency in shrinkage and low tensile resistance is undeniable. However, the aforementioned defects can be partially modified by addition of fibers. On the other hand, possibility of adding waste materials in concrete has provided a new ground for use of recycled concrete aggregates in the construction industry. In this study, a constant combination of recyclable coarse and fine concrete aggregates was used to replace the corresponding aggregates at 50% substitution percentage. Moreover, in order to investigate the effects of fibers on mechanical and durability properties of recycled aggregate concrete, the amounts of 0.5%, 1%, and 1.5% steel fibers (ST) and 0.05%, 0.1% and 0.15% polypropylene (PP) fibers by volumes were used individually and in hybrid forms. Compressive strength, tensile strength, flexural strength, ultrasonic pulse velocity (UPV), water absorption, toughness, elastic modulus and shrinkage of samples were investigated. The results of mechanical properties showed that PP fibers reduced the compressive strength while positive impact of steel fibers was evident both in single and hybrid forms. Tensile and flexural strength of samples were improved and the energy absorption of samples containing fibers increased substantially before and after crack presence. Growth in toughness especially in hybrid fiber-reinforced specimens retarded the propagation of cracks. Modulus of elasticity was decreased by the addition of PP fibers while the contrary trend was observed with the addition of steel fibers. PP fibers decreased the ultrasonic pulse velocity slightly and had undesirable effect on water absorption. However, steel fiber caused negligible decline in UPV and a small impact on water absorption. Steel fibers reduce the drying shrinkage by up to 35% when was applied solely. Using fibers also resulted in increasing the ductility of samples in failure. In addition, mechanical properties changes were also evaluated by statistical analysis of MATLAB software and smoothing spline interpolation on compressive, flexural, and indirect tensile strength. Using shell interpolation, the optimization process in areas without laboratory results led to determining optimal theoretical points in a two-parameter system including steel fibers and polypropylene.

Investigation of Shade Darkening Property of Polydimethylsiloxane and Poly (Dimethyl/Diphenyl Siloxane) Modified with Amino Groups on Dyed Textiles

Mahdi Safi,Fahime Gheisar,Farhood Najafi,Behzad Shirkavand Hadavand 한국섬유공학회 2023 Fibers and polymers Vol.24 No.12

This study aimed to investigate the capability of two silicon-based resins, namely Polydimethylsiloxane (PDMSiA) and Poly (dimethyl/diphenyl siloxane) modified with amino groups (PDMDPhSiA), to induce a visible shade-darkening effect when applied as finishing agents on black-dyed polyester and cotton fabrics. The process involved the utilization of deepening agents with a low refractive index to achieve this visual darkening effect. The analysis encompassed several aspects. FTIR spectroscopy was employed to characterize the chemical structure of the synthetic products. The refractive indexes were quantified using the Swaneopeol method. To gauge the effectiveness of the treatment, the color depth of the treated fabrics was assessed using parameters such as color yield (K/S) and the ratio of the difference in lightness (DL*) to the overall color difference (ΔEab*). Moreover, the study delved into the fastness properties of the dyed fabrics after the finishing process. Comparatively, the results highlighted that the use of PDMSiA resin led to an enhanced color depth in the finished fabrics, outperforming the effects of PDMDPhSiA resin. The evaluation of color fastness demonstrated significant improvements across the board, with all samples achieving a grade of 5 or higher. The study determined that the optimal conditions for applying both resins involved a concentration of 20%, a pick-up rate of 85%, and a curing temperature of 180 °C. These conditions yielded the most favorable outcomes in terms of achieving the desired shade-darkening effect on the dyed fabrics.

Spatio-temporal analysis of fire incidences in urban context: the case study of Mashhad, Iran

Mohammad Mahdi Barati Jozan,Alireza Mohammadi,Aynaz Lotfata,Hamed Tabesh,Behzad Kiani 대한공간정보학회 2024 Spatial Information Research Vol.32 No.1

The study aims to identify fire patterns in Mashhad, the second-most populous city in Iran, between 2015 and 2019. Spatial scan statistics were utilized to determine the spatiotemporal patterns of 29,889 fire events in the research area. There were four primary types of fires: (1) structural fires (39%), (2) vehicle fires (11%), (3) green and open space fires (19%), and (4) others (31%). The interval from 12:00 to 23:00 h was identified as the high-risk period for all fire incidents. Fires were common in the nearby city core. Additionally, three significant hourly spatial-temporal clusters of firefighting operations were identified: the western part of the city between 12:00 and 23:00, the city center between 11:00 and 22:00, and the southeastern part between 11:00 and 22:00. Population density, illiteracy ratio, unemployment ratio, youth ratio, lowincome population, and the number of old buildings might be socio-economic criteria that contribute to the spatiotemporal pattern of urban fires. Urban planners might prioritize high-risk neighborhoods when allocating resources for fire safety. Future research could specifically investigate high-risk regions to identify relevant characteristics in these areas.

A promising treatment for HIV-1 using biosynthesis of metal nanoparticles

Farahnaz Behzad,Fateme Najafi Kalyani,Azam Samadi,Mahdi Adabi 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

Human immunodeficiency virus (HIV) is the aetiological agent of acquired immunodeficiency diseasesyndrome (AIDS). A noticeable public health worry is associated with the fast growth of drug resistanceto the present treatments and also the drugs with negative side effects because of their long-term use. Lately, there has been a quick progress in using metal nanoparticles (MNPs) due to their anti-virus activities. On the other hand, physicochemical procedures for synthesizing MNPs create some problems owingto use of toxic solvents, high consumption of energy, and formation of non-ecofriendly by-products. Therefore, it is vital to develop environment-friendly methods to synthesize MNPs. This study presentsa review of anti-virus effects of MNPs on HIV/AIDS. In addition, we studied the potential of greenMNPs especially silver (Ag), gold (Au), and zinc oxide (ZnO) NPs, to supply a method for treating HIVand future challenges.

The Prostaglandin Synthase 2/cyclooxygenase 2 (PTGS2/COX2) rs5277 Polymorphism Does not Influence Risk of Colorectal Cancer in an Iranian Population

Khorshidi, Fatemeh,Haghighi, Mahdi Montazer,Mojarad, Ehsan Nazemalhosseini,Azimzadeh, Pedram,Damavand, Behzad,Vahedi, Mohsen,Almasi, Shohreh,Aghdaei, Hamid Asadzadeh,Zali, Mohammad Reza Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8

Background: The prostaglandin-endoperoxide synthase 2 [PTGS2, commonly known as cyclooxygenase-2 (COX-2)] is an enzyme induced by proinflammatory stimuli that is often overexpressed in malignant tissue and involved in the synthesis of prostaglandins and thromboxanes, regulators of processes such as inflammation, cell proliferation, and angiogenesis, all relevant for cancer development. We investigated whether a functional genetic polymorphism, rs5277, in COX-2 may have a risk-modifying effect on sporadic colorectal cancer in an Iranian population. Materials and Methods: We conducted a case-control study on 167 patients with colorectal cancer and 197 cancer-free controls in Taleghani Hospital in Tehran, Iran, between 2007 and 2011. Peripheral blood samples of both groups were processed for DNA extraction and genotyping of the COX-2 gene polymorphism (rs5277) using PCR-RFLP. RFLP results were confirmed by direct sequencing. Logistic regression analysis was performed to calculate the adjusted odds ratio (OR) and 95% confidence interval (95% CI). Results: There was no significant difference in the distribution of COX-2 gene rs5277 polymorphism genotype and the allelic form, among CRC patients compared with the healthy control group (p: 0.867). Conclusions: Our results suggest that rs5277 polymorphism in COX2 could not be a good prognostic indicator for patients with CRC.

Analyzing consolidation data to obtain elastic viscoplastic parameters of clay

Le, Thu M.,Fatahi, Behzad,Disfani, Mahdi,Khabbaz, Hadi Techno-Press 2015 Geomechanics & engineering Vol.8 No.4

A nonlinear creep function incorporated into the elastic visco-plastic model may describe the long-term soil deformation more accurately. However, by applying the conventional procedure, there are challenges to determine the model parameters due to limitation of suitable data points. This paper presents a numerical solution to obtain several parameters simultaneously for a nonlinear elastic visco-plastic (EVP) model using the available consolidation data. The finite difference scheme using the Crank-Nicolson procedure is applied to solve a set of coupled partial differential equations of the time dependent strain and pore water pressure dissipation. The model parameters are determined by applying the algorithm of trust-region reflective optimisation in conjunction with the finite difference solution. The proposed method utilises all available consolidation data during dissipation of the excess pore water pressure to determine the required model parameters. Moreover, the reference time in the elastic visco-plastic model can readily be adopted as a unit of time; denoting creep is included in the numerical predictions explicitly from the very first time steps. In this paper, the settlement predictions of thick soft clay layers are presented and discussed to evaluate and compare the accuracy and reliability of the proposed method against the graphical procedure to obtain the model parameters. In addition, comparison of the available experimental results to the numerical predictions confirms the accuracy of the numerical procedure.

Nano-alumina coated with SDS and modified with salicylaldehyde-5-sulfonate for extraction of heavy metals and their determination by anodic stripping voltammetry

Maryam Rajabi,Bahram Mohammadi,Alireza Asghari,Behruz Barfi,Mahdi Behzad 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

A green and highly selective solid phase extraction was employed for simultaneous preconcentration and determination of lead and zinc ions in complex real samples by differential pulse anodic stripping voltammetry. The presented method is based on the adsorption of zinc and lead ions on SDS-coated nano-alumina modified with sodium salicylaldehyde-5-sulfonate (SAS). The influence of effective parameters on the separation and preconcentration of the analytes, such as amount of adsorbent, pH and flow rate of sample, volume and concentration of eluent, and effect of possible matrix ions was investigated. Under the best conditions (eluent: HNO3, 3.0 mL, 3.0 mol L-1; adsorbent: 0.7 g of nanoalumina, 30 mg of SDS, 9.4 mg of SAS; and sample: pH 5), adsorption capacity, enrichment factors, and limits of detection for metal ions were 7.8–8.5 mg g-1, 83–167 and 0.0046–0.026 mg L-1, respectively. Calibration graphs were linear in the range of 0.01–100 and 0.08–150 mg L-1 for Pb (II) and Zn (II), respectively. At the end, the proposed method was successfully applied for determination of the analytes in tap water and different food samples such as rice seed, apple juice, coriander and lettuce.

Photocatalytic degradation of organic dyes using WO3-doped ZnO nanoparticles fixed on a glass surface in aqueous solution

Roya Ebrahimi,Afshin Maleki,Yahya Zandsalimi,Reza Ghanbari,Behzad Shahmoradi,Reza Rezaee,Mahdi Safari,주상우,Hiua Daraei,Shivaraju Harikaranahalli Puttaiah,Omid Giahi 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.73 No.-

The present study aimed at evaluating the application of tungsten oxide-doped zinc oxide nanoparticlesfor the photocatalytic degradation of Direct Blue 15 dye in a sequencing batch reactor. ZnO nanoparticleswere doped with WO3 through hydrothermal synthesis method. To characterize the synthesizednanoparticles scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy,atomic force microscopy, zeta potential analysis, and ultraviolet–visible spectroscopy were used. Theradiation source in this study wasfive 6 W UV lamps. Operational parameters affecting the process,namely pH, light intensity, dopant percentage, dye concentration, and contact time, were evaluated. Theresults of the present study revealed that the efficiency of the photocatalytic process for the degradationof organic dyes was higher at acidic pH values than neutral or basic values. In addition, upon increasingthe light intensity from 172 to 505 W/m2, the efficacy of dye degradation was enhanced from 27.8 to73.5%. Increasing the concentration of the dopant percentage from 1 to 5% w/v increased the degradationefficacy from 30.69 to 73.1%. Increasing the initial dye concentration from 20 to 100 mg/L decreased thedegradation efficacy from 86.9 to 37.5%. Photocatalytic process using WO3-doped ZnO nanoparticlesfixedon a glass surface thus was proven to show a good efficiency for the degradation of organic dye in aquaticsolutions.

The aqueous extract of Allium saralicum R.M. Fritsch efectively treat induced anemia: experimental study on Wistar rats

Samaneh Goorani,Nabi Shariatifar,Niloofar Seydi,Akram Zangeneh,Rohallah Moradi,Behzad Tari,Farzaneh Nazari,Mohammad Mahdi Zangeneh 경희대학교 융합한의과학연구소 2019 Oriental Pharmacy and Experimental Medicine Vol.19 No.4

There are many medicinal plants in traditional medicine which are used to prevent, control, and treat anemia. One of these plants is Allium saralicum R.M. Fritsch. The purpose of our research was to investigate the efect of aqueous extract of A. saralicum leaf in the treatment of hemolytic anemia. In this study, 60 rats were used. Induction of hemolytic anemia was done by three injections of Phenylhydrazine in 50 animals. Then, the rats were divided into six subgroups, including negative healthy control, untreated negative control, and four groups receiving the A. saralicum at 25, 50, 100, and 200 mg/kg concentrations. At the end of day 15 of treatment, the animals of all groups were weight and then sacrifced. The blood, liver and spleen samples were drawn immediately to analyze the hematological, biochemical and histological parameters. All groups of A. saralicum (especially AS200) signifcantly (p≤0.05) reduced the raised concentrations of Fe, ferritin, erythropoietin, ALP, AST, ALT, GGT, cholesterol, LDL, triglyceride, total and conjugated bilirubin, urea, and creatinine and increased the levels of body weight, HDL, total protein, albumin, WBC, lymphocyte, monocytes, platelet, RBC, Hb, PCV, MCV, MCH, and MCHC as compared to the untreated group. Also, A. saralicum at all doses prevented pathological changes in the liver and spleen. In conclusion, because of aqueous extract of A. saralicum leaf anti-anemic property, it can be used as a medical supplement or drug.