Plant Leave as an Indicator for Pollution by Hydrocarbons and Heavy Metals in Al-Zubair City, Southern Iraq

Sajjad W. Jaafar,Sattar J.Al.Khafaji 대한자원환경지질학회 2023 자원환경지질 Vol.56 No.1

The potential sources and spatial distribution of heavy metals and polycyclic aromatic hydrocarbons (PAHs) were investigated in the leaf plants of Al-Zubair city. A total of 14 samples of conocarpus lancifolius plant leaf were collected and analyzed for their heavy metals and PAHs content using inductively coupled plasma mass spectrometry (ICP-MS) and a 7890 Agilent capillary gas chromatograph (GC) respectively. Bioaccumulation factor calculation revealed the highest pollution of heavy metals , due to the activity of a petrochemical in the area. The diagnostic ratio of Ant/(Phe+Ant), BaA/BaA+Chr), In/(In+BghiP), Flu/Pyr, FlA/FlA+Pyr), ΣLMW/ΣHMW are commonly used for determining the origin and source of PAHs in various environmental media. The diagnostic ratio indicated the anthropogenic origin. PAHs with five-to-six membered rings were dominant in the plant leaf, which likely results from anthropogenic activities. The leaves of C. lancifolius have a preponderance of high molecular weight PAHs compared to low molecular weight PAHs, indicating a combustion origin (car exhaust, petroleum emissions, and fossil fuel). C. lancifolius leaves are a reliable indication of atmospheric PAHs absorption. The background level of heavy metals in the city (or the near environment) is in the order of Fe > Cu > Ni > Cr. On the other hand, the bioaccumulation in plant leaves showed greater tendencies as follows: Co>Cd>Zn=As>Cu>Mn>Ni>Pb>Cr>Fe. Cobalt showed high bioaccumulation, indicating strong uptake of Co by plant leaves. These findings point to human activity and car emissions as the primary sources of roadside vegetation pollution in Al-Zubair city.

Modeling of combined thermal and mechanical action in roller compacted concrete dam by three-dimensional finite element method

Abdulrazeg, A.A.,Noorzaei, J.,Mohammed, T.A.,Jaafar, M.S. Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.1

A combined thermal and mechanical action in roller compacted concrete (RCC) dam analysis is carried out using a three-dimensional finite element method. In this work a numerical procedure for the simulation of construction process and service life of RCC dams is presented. It takes into account the more relevant features of the behavior of concrete such as hydration, ageing and creep. A viscoelastic model, including ageing effects and thermal dependent properties is adopted for the concrete. The different isothermal temperature influence on creep and elastic modulus is taken into account by the maturity concept, and the influence of the change of temperature on creep is considered by introducing a transient thermal creep term. Crack index is used to assess the risk of occurrence of crack either at short or long term. This study demonstrates that, the increase of the elastic modulus has been accelerated due to the high temperature of hydration at the initial stage, and consequently stresses are increased.

A new 3D interface element for three dimensional finite element analysis of FRP strengthened RC beams

Kohnehpooshi, O.,Noorzaei, J.,Jaafar, M.S.,Saifulnaz, M.R.R. Techno-Press 2011 Interaction and multiscale mechanics Vol.4 No.4

The analysis of interfacial stresses in structural component has been the subject of several investigations but it still requires more effort and studies. In this study a general three-dimensional interface element has been formulated for stress and displacement analyses in the interfacial area between two adjacent plate bending element and brick element. Interface element has 16 nodes with 5 degrees of freedom (DOF) in each node adjacent to plate bending element and 3 DOF in each node adjacent to brick element. The interface element has ability to transfer three translations from each side of interface element and two rotations in the side adjacent to the plate element. Stiffness matrix of this element was formulated and implemented in three-dimensional finite element code. Application of this element to the reinforced concrete (RC) beam strengthened with fiber reinforced polymer (FRP) including variation of deflection, slip between plate and concrete, normal and shear stresses distributions in FRP plates have been verified using experimental and numerical work of strengthened RC beams carried out by some researchers. The results show that this interface element is effective and can be used for structural component with these types of interface elements.

Modeling of combined thermal and mechanical action in roller compacted concrete dam by three-dimensional finite element method

A.A. Abdulrazeg,J. Noorzaei,T.A. Mohammed,M.S. Jaafar 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.1

A combined thermal and mechanical action in roller compacted concrete (RCC) dam analysis is carried out using a three-dimensional finite element method. In this work a numerical procedure for the simulation of construction process and service life of RCC dams is presented. It takes into account the more relevant features of the behavior of concrete such as hydration, ageing and creep. A viscoelastic model, including ageing effects and thermal dependent properties is adopted for the concrete. The different isothermal temperature influence on creep and elastic modulus is taken into account by the maturity concept, and the influence of the change of temperature on creep is considered by introducing a transient thermal creep term. Crack index is used to assess the risk of occurrence of crack either at short or long term. This study demonstrates that, the increase of the elastic modulus has been accelerated due to the high temperature of hydration at the initial stage, and consequently stresses are increased.

Effect of Stacking Sequences, Fabric Orientations, and Chemical Treatment on the Mechanical Properties of Hybrid Woven Jute–Ramie Composites

C. Tezara,M. Zalinawati,Januar Parlaungan Siregar,J. Jaafar,M. H. M. Hamdan,A. N. Oumer,K. H. Chuah 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.9 No.1

Natural fibres have been widely used in advanced applications, especially in the automotive industry. These fibres are inexpensive, non-abrasive, environmentally friendly, biodegradable, and possess low density with good mechanical properties. The main issue in using natural fibres is their incompatibility with a polymer matrix that lowers the mechanical properties. Therefore, this research analyses the effect of stacking sequences, fibre orientations, and alkali treatment on the mechanical properties of hybrid jute (J) and ramie (R) reinforced vinyl ester (VE) composites. Initially, woven fibres were fabricated based on the 3 and 4—layer stacking sequence with 0° orientation. The characterisation was done to analyse its properties. It was found that the RJJR stacking sequence possessed a tensile strength higher value of 28.90 MPa. The results for the RJJR sequence were fabricated with various fibre orientations such as 0°, 30°, 45°, and 90° to understand the effect of fibre orientation towards the tensile and flexural properties. The tensile and flexural strength with 0° fibre orientation is significantly higher than the other orientations with values of 28.90 MPa and 66.81 MPa, respectively. Besides, alkali treatment with 5 wt.% and 10 wt.% was used to enhance the mechanical properties, where 0° RJJR with 5 wt.% indicated maximum flexural strength with 34.50% increment compared to untreated RJJR. In conclusion, the combination of fibre orientation and lower alkali treatment concentration (5 wt.%) is highly beneficial in improving fibre hybrid composites’ mechanical properties.

Numerical simulation of soil-structure interaction in framed and shear-wall structures

Dalili, M.,Alkarni, A.,Noorzaei, J.,Paknahad, M.,Jaafar, M.S.,Huat, B.B.K. Techno-Press 2011 Interaction and multiscale mechanics Vol.4 No.1

This paper deals with the modeling of the plane frame structure-foundation-soil system. The superstructure along with the foundation beam is idealized as beam bending elements. The soil medium near the foundation beam with stress concentrated is idealized by isoparametric finite elements, and infinite elements are used to represent the far field of the soil media. This paper presents the modeling of shear wall structure-foundation and soil system using the optimal membrane triangular, super and conventional finite elements. Particularly, an alternative formulation is presented for the optimal triangular elements aimed at reducing the programming effort and computational cost. The proposed model is applied to a plane frame-combined footing-soil system. It is shown that the total settlement obtained from the non-linear interactive analysis is about 1.3 to 1.4 times that of the non-interactive analysis. Furthermore, the proposed model was found to be efficient in simulating the shear wall-foundation-soil system, being able to yield results that are similar to those obtained by the conventional finite element method.

Recent trends of heavy metal removal from water/wastewater by membrane technologies

N. Abdullah,N. Yusof,W.J. Lau,J. Jaafar,A.F. Ismail 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.76 No.-

A literature search revealed a lack of up-to-date and detailed review articles on the use of membranetechnologies for heavy metal removal. Thus, this article provides a comprehensive review of theperformance and capability of different membrane processes and discusses the advantages anddisadvantages of each. This review also discusses the technical challenges of existing membrane processand recommends future research to further enhance membrane performance and render it the bestalternative for treating water laden with heavy metals.

Celiac disease in children: increasing prevalence and changing clinical presentations

Isa, Hasan M.,Farid, Eman,Makhlooq, Jaafar J.,Mohamed, Afaf M.,Al-Arayedh, Jumana G.,Alahmed, Fawzeya A.,Medani, Shima The Korean Pediatric Society 2021 Clinical and Experimental Pediatrics (CEP) Vol.64 No.6

Background: Celiac disease (CD) is a chronic autoimmune enteropathy. It results from genetic predisposition and exposure to gluten-containing food. The prevalence and presentation of CD vary among populations. Purpose: This study aimed to describe the prevalence and clinical characteristics of CD in children in Bahrain. Methods: We retrospectively reviewed the medical records of children diagnosed with CD in the pediatric department, Salmaniya Medical Complex, Bahrain, in 1988-2018. Their clinical, biochemical, serological, and histopathological findings were documented. Adherence to the recommended gluten-free diet (GFD) was assessed. Results: Of 86 patients with CD, 67 were included. The CD prevalence was 0.02%. A significant increase in prevalence in the last decade was observed (P<0.0001). Thirty-eight patients (56.7%) were males. The median (interquartile range) age at presentation was 4.45 (1.5-7.3) years. A family history of CD was positive in 13 out of 43 patients (30.2%). Pallor and failure to thrive were the most common presentations. The most frequent associated disease was iron-deficiency anemia in 23 patients (69.7%). Positive serology was found in 32 of 45 patients (71.1%). Marsh-Oberhuber type III was found in 16 of 35 patients (45.7%). Seropositive patients were significantly older (P=0.025) and had more severe duodenal histology (P=0.002). Adherence to GFD was poor in 27 patients (64.3%). Conclusion: This study revealed a significant increase in CD prevalence over the last decade. Atypical presentations were frequent. Most patients had poor adherence to GFD.

Study on synthesis and physical properties of charged surface modifying macromolecules with different end-capping materials for membrane applications

M.N.A. Mohd Norddin,A.F. Ismail,T. Matsuura,R. Sudirman,J. Jaafar,D. Rana 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.6

Polyol and end-capping agent were changed systematically when charged surface modifying macromolecules (cSMMs) were synthesized and characterized. Fourier transform infrared spectroscopy detected different degrees of hydrogen bonding interactions for different polyols and end-capping agents via shifting of absorption bands characteristic to the urethane group. Polyol of the lower molecular weight showed the stronger interaction and thus increased the cSMM’s structural rigidity. The cSMM’s rigidity increased from hydroxyl benzene sulfonate to hydroxyl propane sulfonate when poly(propylene glycol) was used as polyol. The effects of polyol and end-capping agent on the contact angle and water uptake were studied.

Effect of temperature on the transition in deformation modes in Mg single crystals

Sim, Gi-Dong,Xie, Kelvin Y.,Hemker, Kevin J.,El-Awady, Jaafar A. Elsevier 2019 ACTA MATERIALIA Vol.178 No.-

<P><B>Abstract</B></P> <P>Here, an experimental study utilizing <I>in-situ</I> scanning electron microscopy (SEM) micro-compression testing and post-mortem transmission electron microscopy (TEM) imaging is presented to quantify the effect of temperature on the transition in deformation modes in twin-oriented Mg single crystals. Single crystal micropillars were fabricated using FIB milling, then tested by <I>in-situ</I> SEM micro-compression from 20 °C to 225 °C. It is observed that plasticity in the deformed Mg microcrystals at temperatures at and below 100 °C is governed by { 10 1 ¯ 2 } extension twinning. However, an anomalous increase of the flow stresses is observed at 100 °C, which is likely due to paucity of dislocation sources that are required to promote twin boundary migration. At 150 °C and above, extension twinning is suppressed and a continuous plastic flow and strain softening induced by prismatic dislocation mediated plasticity is observed. By comparing the current results with those from bulk scale studies for other hexagonal-closed-pack single crystals (e.g. titanium (Ti) and zirconium (Zr)), a general trend for the effect of temperature on the transition in deformation modes in HCP materials is proposed.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>