Experimental Lnvestigation on Mechanical Characteristics and Environmental Effects on Rubber Concrete

Khorrami, Morteza,Vafai, Abolhassan,Khalilitabas, Ahmad A.,Desai, Chandrakant S.,Ardakani, M. H. Majedi Korea Concrete Institute 2010 International Journal of Concrete Structures and M Vol.4 No.1

The feasibility of the use of scrap tire rubber in concrete was investigated. The tests conducted in two groups: replacing of coarse aggregates with crumb rubber and cement particles with rubber powder. To distinguish the properties of new concrete, the following mechanical and durability tests were designed: compressive, tensile and flexural strength, permeability and water absorption. Rubber addition could affect the concrete properties depend on the type and percentage of the rubber added. Although the rubber addition modifies the mechanical characteristics of concrete in a way, but higher rubber content could not be useful. Concrete durability showed more dependency to the type of rubber instead of percentage of rubber. Moreover, to optimize the mechanical and durability of rubberized concrete, the useful percentage of rubber has been recommended.

Experimental Lnvestigation on Mechanical Characteristics and Environmental Effects on Rubber Concrete

Morteza Khorrami,AbolhassanVafai,Ahmad A. Khalilitabas,Chandrakant S. Desai,M. H. Majedi Ardakani 한국콘크리트학회 2010 International Journal of Concrete Structures and M Vol.4 No.1

The feasibility of the use of scrap tire rubber in concrete was investigated. The tests conducted in two groups: replacing of coarse aggregates with crumb rubber and cement particles with rubber powder. To distinguish the properties of new concrete, the following mechanical and durability tests were designed: compressive, tensile and flexural strength, permeability and water absorption. Rubber addition could affect the concrete properties depend on the type and percentage of the rubber added. Although the rubber addition modifies the mechanical characteristics of concrete in a way, but higher rubber content could not be useful. Concrete durability showed more dependency to the type of rubber instead of percentage of rubber. Moreover, to optimize the mechanical and durability of rubberized concrete, the useful percentage of rubber has been recommended.

Experimental Investigation on Mechanical characteristics and Environmental Effects on Rubber Concrete

Morteza Khorrami,AbolhassanVafai,Ahmad A. khalilitabas,Chandrakant S. Desai,M.H. Majedi Ardakani 한국콘크리트학회 2010 International Journal of Concrete Structures and M Vol.4 No.1

The feasibility of the use of scrap tire rubber in concrete was investigated. The tests conducted in two groups: replacing of coarse aggregates with crumb rubber and cement particles with rubber powder. To distinguish the properties of new concrete,the following mechanical and durability tests were designed: compressive, tensile and flexural strength, permeability and water absorption. Rubber addition could affect the concrete properties depend on the type and percentage of the rubber added. Although the rubber addition modifies the mechanical characteristics of concrete in a way, but higher rubber content could not be useful. Concrete durability showed more dependency to the type of rubber instead of percentage of rubber. Moreover, to optimize the mechanical and durability of rubberized concrete, the useful percentage of rubber has been recommended.

Post Deformation at Room and Cryogenic Temperature Cooling Media on Severely Deformed 1050-Aluminum

M. Sarkari Khorrami,M. Kazeminezhad 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.2

The annealed 1050-aluminum sheets were initially subjected to the severe plastic deformation through two passes of constrainedgroove pressing (CGP) process. The obtained specimens were post-deformed by friction stir processing at roomand cryogenic temperature cooling media. The microstructure evolutions during mentioned processes in terms of grainstructure, misorientation distribution, and grain orientation spread (GOS) were characterized using electron backscattereddiffraction. The annealed sample contained a large number of “recrystallized” grains and relatively large fraction (78%) ofhigh-angle grain boundaries (HAGBs). When CGP process was applied on the annealed specimen, the elongated grainswith interior substructure were developed, which was responsible for the formation of 80% low-angle grain boundaries. TheGOS map of the severely deformed specimen manifested the formation of 43% “distorted” and 51% “substructured” grains. The post deformation of severely deformed aluminum at room temperature led to the increase in the fraction of HAGBsfrom 20 to 60%. Also, it gave rise to the formation of “recrystallized” grains with the average size of 13 μm, which werecoarser than the grains predicted by Zener–Hollomon parameter. This was attributed to the occurrence of appreciable graingrowth during post deformation. In the case of post deformation at cryogenic temperature cooling medium, the grain sizewas decreased, which was in well agreement with the predicted grain size. The cumulative distribution of misorientationwas the same for both processing routes. Mechanical properties characterizations in terms of nano-indentation and tensiletests revealed that the post deformation process led to the reduction in hardness, yield stress, and ultimate tensile strengthof the severely deformed aluminum.

Effect of calcination temperature on the particle sizes of zinc ferrite prepared by a combination of sol-gel auto combustion and ultrasonic irradiation techniques

S. Abedini Khorrami,G. Mahmoudzadeh,S. S. Madani,F. Gharib 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.5

ZnFe2O4 nanocrystallites were synthesized successfully by a combination of sol-gel auto combustion and ultrasonic irradiation techniques. The influence of the calcination temperature on the particle sizes was investigated. The particles have been calcined at temperatures varying from 400 to 900 oC. The studies were carried out using XRD and SEM techniques. The gradual increase in the crystallite size with the calcination temperature indicates the formation of bigger particles by the calcination.

Seismic response of RC structures rehabilitated with SMA under near-field earthquakes

Shiravand, M.R.,Khorrami Nejad, A.,Bayanifar, M.H. Techno-Press 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.4

During recent earthquakes, a significant number of concrete structures suffered extensive damage. Conventional reinforced concrete structures are designed for life-time safety that may see permanent inelastic deformation after severe earthquakes. Hence, there is a need to utilize adequate materials that have the ability to tolerate large deformation and get back to their original shape. Super-elastic shape memory alloy (SMA) is a smart material with unique properties, such as the ability to regain undeformed shape by unloading or heating. In this research, four different stories (three, five, seven and nine) of reinforced concrete (RC) buildings have been studied and subjected to near-field ground motions. For each building, two different types of reinforcement detailing are considered, including (1) conventional steel reinforcement (RC frame) and (2) steel-SMA reinforcement (SMA RC frame), with SMA bars being used at plastic zones of beams and steel bars in other regions. Nonlinear time history analyses have been performed by "SeismoStruct" finite element software. The results indicate that the application of SMA materials in plastic hinge regions of the beams lead to reduction of the residual displacement and consequently post-earthquake repairs. In general, it can be said that shape memory alloy materials reduce structural damage and retrofit costs.

The Effects of Thyme and Cinnamon Essential Oils on Performance, Rumen Fermentation and Blood Metabolites in Holstein Calves Consuming High Concentrate Diet

Vakili, A.R.,Khorrami, Behzad,Mesgaran, M. Danesh,Parand, E. Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.7

Essential oils have been shown to favorably effect in vitro ruminal fermentation, but there are few in vivo studies that have examined animal responses. The objective of this study was to evaluate the effects of thyme (THY) and cinnamon (CIN) essential oils on feed intake, growth performance, ruminal fermentation and blood metabolites in feedlot calves fed high-concentrate diets. Twelve growing Holstein calves ($213{\pm}17kg$ initial BW) were used in a completely randomized design and received their respective dietary treatments for 45 d. Treatments were: 1-control (no additive), 2-THY (5 g/d/calf) and 3-CIN (5 g/d/calf). Calves were fed ad libitum diets consisting of 15% forage and 85% concentrate, and adapted to the finishing diet by gradually increasing the concentrate ratio with feeding a series of transition diets 5 wk before the experiment started. Supplementation of THY or CIN did not affect DMI and ADG, and feed efficiency was similar between treatment groups. There were no effects of additives on ruminal pH and rumen concentrations of ammonia nitrogen and total VFA; whereas molar proportion of acetate and ratio of acetate to propionate decreased, and the molar proportion of propionate increased with THY and CIN supplementation. Rumen molar concentration of butyrate was significantly increased by adding CIN compared to control; but no change was observed with THY compared with control group. No effects of THY, or CIN were observed on valerate, isobutyrate or isovalerate proportions. Plasma concentrations of glucose, cholesterol, triglyceride, urea-N, ${\beta}$-hydroxybutyrate, alanine aminotransferase and aspartate aminotransferase were not changed by feeding THY or CIN. Results from this study suggest that supplementing a feedlot finishing diet with THY or CIN essential oil might be useful as ruminal fermentation modifiers in beef production systems, but has minor impacts on blood metabolites.

Surfactant effect on synthesize of SrAl2O4 nanoparticles prepared by reverse micelle process

Azita Moheb,Saeid Abedini Khorramie,Shahram Moradi Dehaghi 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.2

Strontium aluminate (SrAl2O4) spinel nanoparticles were synthesized by microemulsion method using micro-reactors made ofdifferent nonionic surfactants (Span 20, Span 40 and Span 60) in a nonpolar solvent cyclohexane. The synthesizednanomaterials were characterized by X-ray diffraction (XRD) technique. The morphology of the synthesized materials wasstudied by field emission scanning electron microscope (FESEM). The average particles size was estimated by XRD andtransmission electron microscope (TEM) with using software of IMAGE J. The effect of different surfactants on the particlessize and morphology was determined. It was found that the average particles size was decreased by decreasing HLB(Hydrophilic-Lipophilic Balance) of surfactants and also the average particles size was decreased from 31 to 21 nm. HLB ofsurfactants is a major factor in controlling the final particles size of SrAl2O4 powder. Dislocation of peaks (2θ) in XRD withdecreasing HLB of surfactant was decreased slightly. The XRD analysis of all the powders indicated the formation of singlephasespinel structure on calcinations.

Calcination temperature and molar ratio effects of nanosized CeO2 and La2O3/γ-Al2O3 synthesized within reverse micelles of surfactant/cyclohexane/ water microemulsion

Roshanak Lotfi,Saeid Abedini Khorrami 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.9

A porous composite of ceria and lanthana/g-alumina was prepared by inverse microemulsion method. The precursor is heatedat several calcination temperature between 823 to 1123 K. Also, the effect of different molar ratio of Ce : La on thecrystallization was studied. The study of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electronmicroscopy (SEM) and temperature programmed reduction (TPR) suggested that well crystalline nanosized particles areobtained. The product samples possess mesoporosity with broadly distributed pores between 14 to 22 nm diameter. Surfacearea increases by increasing the calcination temperature. Also, the particle size of the composite samples decreases with anincreasing in molar ratio of Ce : La.

Surfactant effect on synthesize of BaAl2O4 nanoparticles prepared by reverse micelle process

Azita Moheb,Saeid Abedini Khorramie,Shahram Moradi Dehaghi 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.3

Barium aluminate (BaAl2O4) spinel nanoparticles were prepared by a reverse micelle method using micro-reactors made ofdifferent nonionic surfactants (Span 20, Span 40 and Span 60) in a nonpolar solvent benzene. The synthesized nanomaterialswere characterized by X-ray diffraction (XRD) technique. The morphology of the synthesized materials was studied by fieldemission scanning electron microscope (FESEM). Particle size was estimated by XRD and transmission electron microscope(TEM) with using software of ImageJ. The effect of different surfactants on the particles size and morphology was determined. The results revealed, that particle size was increased by decreasing HLB (Hydrophilic-Lipophilic Balance) of surfactants andalso particle size was increased from 23 to 35 nm. HLB of surfactants is a major factor in controlling the final particles sizeof BaAl2O4 powder. The X-ray powder diffraction analysis indicated, all the formation of hexagonal phase on calcinations. Dislocation of peaks (2θ) in XRD with decreasing HLB of surfactant was decreased slightly.