• Title/Summary/Keyword: SAFA

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Synthesis and characterization of sugarcane bagasse/zinc aluminium and apple peel/zinc aluminium biocomposites: Application for removal of reactive and acid dyes

  • Safa, Yusra;Tariq, Saadia Rashid;Bhatti, Haq Nawaz;Sultan, Misbah;Bibi, Ismat;Nouren, Shazia
    • Membrane and Water Treatment
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    • v.9 no.5
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    • pp.301-307
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    • 2018
  • In this research work, synthesis of sugarcane bagasse/zinc aluminium biocomposite and apple peel/zinc aluminium biocomposite and their application for removal of Reactive Red-241 and Acid Orange-7, respectively, was studied using various parameters. At pH 2 the sorption was the highest for both dyes. The trend showed that the dye sorption declined by decreasing the biocomposite dose and enhanced by increasing the dye concentration and temperature. Equilibrium was achieved at 60 minutes for Reactive Red-241 onto sugarcane bagasse/zinc aluminium biocomposite and 90 minutes for Acid Orange-7 onto apple peel/zinc aluminium biocomposite.The research data was good fitted to pseudo-2nd-order kinetic model and Langmuir isotherm. FT-IR analysis was used to confirm the biosorption of the selected dyes at the surface of biosorbent through various binding sites. Surface morphology modification of both biocomposites before and after biosorption was inspected through SEM. Crystallinity of biocomposite was examined through XRD analysis. It was implied that sugarcane bagasse/ zinc aluminium biocomposite and apple peel/ zinc aluminium biocomposite are good adsorbents for dyes elimination from aqueous solutions.

A new quasi-3D higher shear deformation theory for vibration of functionally graded carbon nanotube-reinforced composite beams resting on elastic foundation

  • Hadji, Lazreg;Meziane, Mohamed Ait Amar;Safa, Abdelkader
    • Structural Engineering and Mechanics
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    • v.66 no.6
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    • pp.771-781
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    • 2018
  • This study deals with free vibrations analysis with stretching effect of nanocomposite beams reinforced by single-walled carbon nanotubes (SWCNTs) resting on an elastic foundation. Four different carbon nanotubes (CNTs) distributions including uniform and three types of functionally graded distributions of CNTs through the thickness are considered. The rule of mixture is used to describe the effective material properties of the nanocomposite beams. The significant feature of this model is that, in addition to including the shear deformation effect and stretching effect it deals with only 4 unknowns without including a shear correction factor. The governing equations are derived through using Hamilton's principle. Natural frequencies are obtained for nanocomposite beams. The mathematical models provided in this paper are numerically validated by comparison with some available results. New results of free vibration analyses of CNTRC beams based on the present theory with stretching effect is presented and discussed in details. The effects of different parameters of the beam on the vibration responses of CNTRC beam are discussed.

AUTOCOMMUTATORS AND AUTO-BELL GROUPS

  • Moghaddam, Mohammad Reza R.;Safa, Hesam;Mousavi, Azam K.
    • Bulletin of the Korean Mathematical Society
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    • v.51 no.4
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    • pp.923-931
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    • 2014
  • Let x be an element of a group G and be an automorphism of G. Then for a positive integer n, the autocommutator $[x,_n{\alpha}]$ is defined inductively by $[x,{\alpha}]=x^{-1}x^{\alpha}=x^{-1}{\alpha}(x)$ and $[x,_{n+1}{\alpha}]=[[x,_n{\alpha}],{\alpha}]$. We call the group G to be n-auto-Engel if $[x,_n{\alpha}]=[{\alpha},_nx]=1$ for all $x{\in}G$ and every ${\alpha}{\in}Aut(G)$, where $[{\alpha},x]=[x,{\alpha}]^{-1}$. Also, for any integer $n{\neq}0$, 1, a group G is called an n-auto-Bell group when $[x^n,{\alpha}]=[x,{\alpha}^n]$ for every $x{\in}G$ and each ${\alpha}{\in}Aut(G)$. In this paper, we investigate the properties of such groups and show that if G is an n-auto-Bell group, then the factor group $G/L_3(G)$ has finite exponent dividing 2n(n-1), where $L_3(G)$ is the third term of the upper autocentral series of G. Also, we give some examples and results about n-auto-Bell abelian groups.

Potential of adaptive neuro fuzzy inference system for evaluating the factors affecting steel-concrete composite beam's shear strength

  • Safa, M.;Shariati, M.;Ibrahim, Z.;Toghroli, A.;Baharom, Shahrizan Bin;Nor, Norazman M.;Petkovic, Dalibor
    • Steel and Composite Structures
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    • v.21 no.3
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    • pp.679-688
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    • 2016
  • Structural design of a composite beam is influenced by two main factors, strength and ductility. For the design to be effective for a composite beam, say an RC slab and a steel I beam, the shear strength of the composite beam and ductility have to carefully estimate with the help of displacements between the two members. In this investigation the shear strengths of steel-concrete composite beams was analyzed based on the respective variable parameters. The methodology used by ANFIS (Adaptive Neuro Fuzzy Inference System) has been adopted for this purpose. The detection of the predominant factors affecting the shear strength steel-concrete composite beam was achieved by use of ANFIS process for variable selection. The results show that concrete compression strength has the highest influence on the shear strength capacity of composite beam.

Comparison of dynamic behavior of shallow foundations based on pile and geosynthetic materials in fine-grained clayey soils

  • Shariati, Mahdi;Azar, Sadaf Mahmoudi;Arjomand, Mohammad-Ali;Tehrani, Hesam Salmani;Daei, Mojtaba;Safa, Maryam
    • Geomechanics and Engineering
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    • v.19 no.6
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    • pp.473-484
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    • 2019
  • In this paper, the geotechnical report of the Northern Fereshteh area in Tabriz is used and the characteristics of shallow foundation of a single pile and compared pile group and geogrid in terms of the settlement of a building foundation on clayey soil. Additionally, impacts of existing variables such as the number of geogrid layers, the length of the pile, and the depth of groundwater level affected by the dynamic load caused by the Taiwan Jiji earthquake via numerical analysis using PLAXIS software are examined. The results of fifty-four models indicated that the construction of a pile group with a diameter of 1 meter and a length of 14 meters significantly diminished the consolidation settlement of the soil in the Northern Fereshteh area, where the settlement value has been triggered by the load inflicted by earthquake. Moreover, the construction of four layers of geogrid at intervals of one meter led to a significant decrease in the settlement. Finally, after reaching a maximum depth, it had no reducing effects on the foundation settlement.

Strain rate effects on soil-geosynthetic interaction in fine-grained soil

  • Safa, Maryam;Maleka, Amin;Arjomand, Mohammad-Ali;Khorami, Masoud;Shariati, Mahdi
    • Geomechanics and Engineering
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    • v.19 no.6
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    • pp.533-542
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    • 2019
  • Geosynthetic reinforced soil method in coarse-grained soils has been widely used in last decades. Two effective factors on soil-geosynthetic interaction are confining stresses and loading rate in clay. In terms of methodology, one pull-out test with four different strain rates, namely 0.75, 1.25, 1.75 and 2.25 mm/min, and three different normal stresses equal to 20, 50, and 80 kg have been performed on specimens with dimensions of 30×30×17 cm in the saturated, consolidated condition. The obtained results have demonstrated that activation of geosynthetic strength at contact surface depends on the applied stress. In addition, the increase in normal stress would increase the shear strength at contact surface between clay and geogrid. Moreover, it is concluded that the strain rate increment would increase the shear strength.

Improving Productive and Reproductive Performance of Holstein Dairy Cows through Dry Period Management

  • Safa, S.;Soleimani, A.;Heravi Moussavi, A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.5
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    • pp.630-637
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    • 2013
  • To determine the effects of dry period (DP) length on milk yield, milk composition, some blood metabolites, complete blood count (CBC), body weight and score and follicular status, twenty five primiparous and multiparous Holstein cows were assigned to a completely randomized design with DP-60 (n = 13) and DP-20 (n = 12) dry period lengths. Cows in the DP-60 produced more milk, protein, SNF, serum non-esterified fatty acids (NEFA) and beta hydroxyl butyrate acid (BHBA) compared with cows in DP-20 ($p{\leq}0.05$). Serum glucose, blood urea nitrogen (BUN), urea, and glutamic oxaloacetic transaminase (GOT) were all similar among the treatments. Body Condition Score (BCS), body weight (BW), complete blood count (CBC) and health problems were similar between the treatments. Diameter of the first dominant follicle and diameter of the dominant follicle on d 14 were different among the treatments. Thus, results of this study showed that reducing the dry period length to DP-20 had a negative effect on milk production, milk composition and reproductive performance in Holstein dairy cows.

Influence of Breed, Slaughter Weight and Gender on Chemical Composition of Beef. Part 2. Fatty Acid Composition of Fat in Rib Samples

  • Hollo, G.;Csapo, J.;Szucs, E.;Tozser, J.;Repa, I.;Hollo, I.
    • Asian-Australasian Journal of Animal Sciences
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    • v.14 no.12
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    • pp.1719-1723
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    • 2001
  • The effect of slaughter weight and gender on fatty acid composition of homogenised rib samples of Hungarian Simmental (HS) and Holstein-Friesian (HF) cattle breeds was investigated. In the first experiment 22 Hungarian Simmental and 18 Holstein-Friesian cattle's meat, in the second experiment 15 females and 12 males Holstein-Friesian cattle's meat was analysed on fatty acid content. Saturated and mono- or polyunsaturated fatty acid profile did not seem to vary either by breed or by slaughter weight categories. The effect of gender, however, proved to be significant in influencing the quantity of polyunsaturated fatty acids, including linoleic and linolenic acids, as well as polyunsaturated fatty/saturated fatty acids (PUFA/SAFA) ratio. The amount of polyunsaturated fatty acids (PUFA) was higher in males than in females. Negative correlation was established between the quantity of PUFA and the amount of adipose tissue in rib samples.

Front End Planning Tool (FEPT) Based on an Electronic Process Management

  • Safa, Mahdi;Haas, Carl T.;Hipel, Keith W.;Gray, Joel
    • Journal of Construction Engineering and Project Management
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    • v.3 no.2
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    • pp.1-12
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    • 2013
  • Research indicates that good front-end planning (FEP) results in the achievement of higher levels of project performance. By facilitating collaboration among stakeholders in diverse locations with the use of workflow-enabled processes, such pressures can be reduced, and the overall process and results of FEP can be improved. With these goals, a front-end planning tool (FEPT) has been developed as support for owners and major contractors who are engaged in front-end planning. This paper presents the new FEPT and describes how it has been used for construction megaprojects in the nuclear power, oil and gas, and mining industries. The paper begins with the definitions related to and an explanation of the general process for implementing and applying the FEPT and then describes and analyzes how the FEPT was applied in case study projects in order to test its validity. The results indicate that the FEPT increases the efficiency and effectiveness of front-end planning for the megaprojects studied and that it has the potential to produce similar results for other megaprojects.

Experimental study of the behavior of composite timber columns confined with hollow rectangular steel sections under compression

  • Razavian, Leila;Naghipour, Morteza;Shariati, Mahdi;Safa, Maryam
    • Structural Engineering and Mechanics
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    • v.74 no.1
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    • pp.145-156
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    • 2020
  • There are separate merits and demerits to wood and steel. The combination of wood and steel as a compound section is able to improve the properties of both and ultimately increase their final bearing capacity. The composite cross-section made of steel and wood has higher hardness while showing more ductility and the local buckling of steel is delayed or completely prevented. The purpose of this study is to investigate the behavior of composite columns enclosed in wooden logs and the hollow sections of steel that will be examined in a laboratory environment under the axial load to determine the final bearing capacity and sample deformation. In terms of methodology, steel sheet and carbon fiber reinforced polymer sheet (FRP) are tested to construct hollow rectangular sections and reinforce timber. Besides, the method of connecting hollow sections and timber including glue and screw has been also investigated. As a result, timber lumber enclosed with carbon fiber-reinforced polymer sheets in which fibers are horizontally located at 90° are more resistant with better ductility.