Fatigue crack effect on magnetic flux leakage for A283 grade C steel

M.I.M. Ahmad,A. Arifin,S. ABDULLAH,W.Z.W. Jusoh,S.S.K. Singh 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.6

This paper presents the characterization of fatigue crack in the A283 Grade C steel using the MMM method by identifying the effects of magnetic flux leakage towards the crack growth rate, da/dN, and crack length.The previous and current research on the relation between MMM parameters and fatigue crack effect is still unclear and requires specific analysis to validate that. This method is considered to be a passive magnetic method among other Non-Destructive Testing (NDT) methods. The tension-tension fatigue test was conducted with a testing frequency of 10 Hz with 4 kN loaded, meanwhile the MMM response signals were captured using a MMM instrument. A correlation between the crack growth rate and magnetic flux leakage produces a sigmoid shape curve with a constant values which present the gradient, m value is in the ranges of 1.4357 to 4.0506, and the y-intercept, log C in the ranges of 4×10<SUP>-7</SUP> to 0.0303. Moreover, a linear relation was obtained between the crack length and magnetic flux leakage which present the R-Squared values is at 0.830 to 0.978. Therefore, MMM method has their own capability to investigate and characterize the fatigue crack effects as a main source of fracture mechanism for ferrous-based materials.

Prion Protein Genotypes in Pakistani Goats

Babar, M.E.,Nawaz, M.,Nasim, A.,Abdullah, M.,Imran, M.,Jabeen, R.,Chatha, S.A.,Haq, A.U.,Nawaz, A.,Mustafa, H.,Nadeem, A. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.7

The PCR-amplified prion protein (PrP) gene was sequenced to determine the frequency of scrapie-associated as well as novel PrP genotypes in 72 healthy goats representing five breeds. A total of six genotypes were detected, resulting from the three reported 143 (H/R), 154 (R/H) and 240 (S/P) and the two novel 39 (S/R) and 185 (I/F) amino acid polymorphisms. Of the four silent mutations 42 (a$\rightarrow$g), 138 (c$\rightarrow$t), 231 (c$\rightarrow$a) and 237 (g$\rightarrow$c) detected in this study, 237 (g$\rightarrow$c) is novel. A genotype (SIP/RFP) harboring three amino acid polymorphisms 39 (S/R), 185 (I/F) and 240 (S/P) was found in few goats. Although both scrapie-associated genotypes with 143 (H/R) and 154 (R/H) polymorphisms and others with 39 (S/R), 185 (I/F) and 240 (S/P) polymorphisms were present in the studied Pakistani goats, their frequency was lower than that of the wild-type genotype SHRIS/SHRIS (34.7%). These results emphasize the need for further sequencing of the PrP gene in a large number of goats representing the five studied breeds, so that overall PrP variability can be assessed in these breeds in research addressing future concerns about scrapie.

A review on thermochemical seasonal solar energy storage materials and modeling methods

ABDULLAH,Koushaeian M.,Shah N. A.,정재동 대한설비공학회 2024 International Journal of Air-Conditioning and Refr Vol.32 No.1

In the current era, national and international energy strategies are increasingly focused on promoting the adoption of clean and sustainable energy sources. In this perspective, thermal energy storage (TES) is essential in developing sustainable energy systems. Researchers examined thermochemical heat storage because of its benefits over sensible and latent heat storage systems, such as higher energy density and decreased heat loss. Solar energy is a promising alternative among the numerous renewable energy sources. As a result, this study provides an overview of thermochemical heat storage materials, focusing on materials utilized by solar energy systems in buildings. The research examines the storage materials used in relevant studies and the models used to predict and enhance system performance.

A strain-based wire breakage identification algorithm for unbonded PT tendons

A.B.M. Abdullah,Jennifer A. Rice,H.R. Hamilton 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.16 No.3

Tendon failures in bonded post-tensioned bridges over the last two decades have motivated ongoing investigations on various aspects of unbonded tendons and their monitoring methods. Recent research shows that change of strain distribution in anchor heads can be useful in detecting wire breakage in unbonded construction. Based on this strain variation, this paper develops a damage detection model that enables an automated tendon monitoring system to identify and locate wire breaks. The first part of this paper presents an experimental program conducted to study the strain variation in anchor heads by generating wire breaks using a mechanical device. The program comprised three sets of tests with fully populated 19-strand anchor head and evaluated the levels of strain variation with number of wire breaks in different strands. The sensitivity of strain variation with wire breaks in circumferential and radial directions of anchor head in addition to the axial direction (parallel to the strand) were investigated and the measured axial strains were found to be the most sensitive. The second part of the paper focuses on formulating the wire breakage detection framework. A finite element model of the anchorage assembly was created to demonstrate the algorithm as well as to investigate the asymmetric strain distribution observed in experimental results. In addition, as almost inevitably encountered during tendon stressing, the effects of differential wedge seating on the proposed model have been analyzed. A sensitivity analysis has been performed at the end to assess the robustness of the model with random measurement errors.

Evaluating an adhesive effect on core surface configuration for sandwich panel with peel simulation approach

M. K. Faidzi,S. ABDULLAH,M. F. Abdullah,S.S.K. Singh,A. H. Azman 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

This paper investigates the adhesive effect between the surface layer of sandwich panel with three different core surface configurations by using a peel simulation approach. The sandwich panels with cavity on the core structure can potentially be highly vulnerable to debonding phenomenon when subjected to extreme loading. The three-dimensional sandwich panels based on ASTM D1876 were developed with a finite element modelling and subjected to a constant loading magnitude of 100 MPa in two force directions of 90° and 180°. The result shows that the sandwich panel with a honeycomb core and a dimpled surface core showed increments in stress distributions at bonding area (85 % and 12.8 % at the force direction of 90°; 69.9 % and 11.6 % at the force direction of 180°) compared to that with a solid plate core. Nevertheless, the high shear stress was revealed at a large adhesive area, indicating the high potential for debonding to occur at the adhesive area between panel surface layers. This stress was directly proportional to the total deformation. The size of the adhesive area influences the bonding strength, but an extra reduction in the core density could lead to the early failure of the sandwich panel.

New issue of GaN nanoparticles solar cell

M.A. Qaeed,K. Ibrahim,K.M.A. Saron,M.S. Mukhlif,A. Ismail,Nezar G. Elfadill,Khaled M. Chahrour,Q.N. Abdullah,K.S.A. Aldroobi 한국물리학회 2015 Current Applied Physics Vol.15 No.4

This study involves the synthesis of gallium nitride (GaN) nanoparticles (NPs) under different low temperatures using a simple chemical method. The nanoparticles are spin coated on Si substrate to fabricate the solar cell. The FESEM images obtained indicate the presence of cubic GaN nanoparticle with average diameter of 50 nm synthesized at 90 ℃. The spin coating technique deposited n-GaN NPs/Si(111) produced a heterojunction solar cell with fill factor of 0.56 and conversion efficiency of 2.06%. Based on these results, this study proposes a novel low cost technique for the fabrication of GaN NPs solar cells.

Efficient electrochemical detection of L-lactic acid using platinum nanoparticle decorated Chitosan/ZnTiO3 nanocomposites

M. Faisal,M.M. Alam,Jahir Ahmed,Abdullah M. Asiri,S.A. Alsareii,Raja Saad Alruwais,Norah Faihan Alqahtani,Mohammed M. Rahman,Farid A. Harraz 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

Herein, a facile L-lactic acid electrochemical sensor based on Pt-nanoparticles (NPs)@Chitosan/ZnTiO3nanocomposites (NCs) coated on a glassy carbon electrode (GCE) is demonstrated. Ultra-sonicationmethod followed by irradiation using an Osram Hg-lamp was applied to prepare Pt-NPs@Chitosan/ZnTiO3 NCs, and the characterization of prepared NCs was executed by Field Emission ScanningElectron Microscopy FESEM, Energy Dispersive Spectroscopy EDS, Transmission Electron MicroscopyTEM, High Resolution Transmission Electron Microscopy HRTEM, Fourier Transform InfraredSpectroscopy FTIR, Ultraviolet–visible spectroscopy UV–vis., and X ray Diffraction XRD analysis. A linearcurrent versus potential responses relation was obtained in a concentration range of L-lactic acid of 0. 30 2.40 mM at differential pulse voltammetric (DPV) analysis in a pH 7.0 buffer medium and resultedconcentration range was defined as the dynamic detection range (LDR) for L-lactic acid analysis. The Llacticacid sensor sensitivity (0.4529 lAlM-1cm2), limit of detection (LOD; 22.36 ± 1.12 lM), and limitof quantification (LOQ; 79.88 lM) were obtained. Besides this, the sensor reproducibility and responsetime were found to be reliable. Finally, the assembled sensor probe was validated by the testing of realsamples, which exhibited acceptable and satisfied results. It is introduced a new route for the detection ofchemicals using novel nanocomposite materials by electrochemical approach for the safety of healthcarefields in a broad scales.

Protective Effect of Portulaca oleracea Extract Against Lipopolysaccharide-Induced Neuroinflammation, Memory Decline, and Oxidative Stress in Mice: Potential Role of miR-146a and miR-let 7

Rasha M. Hussein,Ahmed M. Youssef,Mousa K. Magharbeh,Saed M. Al-Dalaen,Nariman A. Al-Jawabri,Taymaa N. Al-Nawaiseh,Abdullah Al-Jwanieh,Fakhir S. Al-Ani 한국식품영양과학회 2022 Journal of medicinal food Vol.25 No.8

Neuroinflammation is an adaptive immune response to the central nervous system (CNS) injury induced by infection or toxins. MicroRNAs (miRs) showed critical roles in neuroinflammation as either proinflammatory or anti-inflammatory molecules. Interestingly, Portulaca oleracea (purslane) is an edible plant capable of ameliorating several diseases, including headache, burns, and diabetes; however, its effect on the neuroinflammation-associated miRs was not previously investigated. This study aimed to investigate the effect of aqueous purslane extract on the neuroinflammation induced by lipopolysaccharide (LPS) in mice and to identify its effect on animal cognition, oxidative stress, and expressions of miR-146a and miR-let 7. Adult mice were divided into the following groups: Normal group, LPS group, and Purslane+LPS group. Novel target recognition test, brain histopathology, and measurement of oxidative stress and inflammatory markers were performed. The results showed that LPS group exhibited significant decline in the cognitive memory, brain histopathological injury and a decrease in the number of intact neurons compared to the normal group. Furthermore, the LPS group showed a significant increase in malondialdehyde concentration, whereas superoxide dismutase and catalase activities were decreased. The LPS group also showed an increase in the inflammatory markers tumor necrosis factor-α and nuclear factor kappa B and downregulation of miR-146a and miR-let 7 expressions in the brain cells compared to the normal group, P value <.05. Interestingly, all these changes were reversed by administration of the aqueous purslane extract. In conclusion, the aqueous purslane extract protected from LPS-induced neuroinflammation and memory decline in mice through antioxidant and anti-inflammatory effect where upregulation of miR-146a and miR-1et 7 expressions was involved.

Lean Cu-immobilized Pt and Pd films/–H+ Conducting Membrane Assemblies: Relative Electrocatalytic Nitrate Reduction Activities

Mohammad A. Hasnat,Sami Ben Aoun,Mohammed M. Rahman,Abdullah M. Asiri,Norita Mohamed 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.28 No.-

Asymmetric reactors having the configuration (PtjNafionjM–Cu, M = Pt, Pd) were designed and appliedto the electrocatalytic nitrate reduction reaction (NRR) with no supporting electrolyte. Theelectrochemically–fabricated Cu–M (M = Pt, Pd) catalysts showed a highly-efficient catalytic activityby effectively reducing more than ca. 99% of nitrate ions, under static-reactor conditions, with first-orderrate constants of ca. 0.040 min 1 and ca. 0.057 min 1 for Cu–Pt and Cu–Pd, respectively. Similarreactivity trends were observed under flow mode irrespective of flow rates while NRR rates werepredominantly controlled by diffusion-limited mass-transfer. A maximum of ca. 93% nitrate removal atCu–Pd catalyst was achieved within ca. 60 min. The comparatively lower CuO content of ca. 9%, asconfirmed by XANES, resulted in a greater number of free NRR active sites inducing the superior catalyticactivity of the Cu–Pd catalyst. On the other hand, NRR product selectivity investigations showed that Cu–Pd catalyst was highly ammonia–selective with a maximum of ca. 24% selectivity at a flow rate of0.1 mL min 1, while Cu–Pt catalyst was much selective to intermediate nitrite ions reaching a maximumof ca. 35% selectivity at the same flow rate.

Salvage flow diverter stent across the posterior communicating artery for persistent retrograde filling of a giant internal carotid artery aneurysm after parent vessel occlusion

Manzoor Muhammad Usman,AlRashed Abdullah A.,Alghabban Fatimah A.,Alqahtani Sultan M.,Alturki Abdulrahman Y. 대한뇌혈관외과학회 2021 Journal of Cerebrovascular and Endovascular Neuros Vol.23 No.2

Giant internal carotid artery (ICA) aneurysms are complex vascular lesions which are difficult to treat with open as well as endovascular surgery. Parent vessel occlusion is a well-established treatment option for such aneurysms. However, there have been a few reported cases of ruptured aneurysms related to the persistent retrograde filling after parent vessel occlusion. We report a case which highlights the usage of the flow diverter stent as a potential treatment strategy for the management of retrograde filling of aneurysms. A 54-year-old female was found to have a giant left ICA aneurysm on a brain magnetic resonance imaging during workup for headaches. She underwent occlusion of the left ICA proximal to the aneurysm using multiple coils. However, follow up angiograms after 6 months and 2 years demonstrated persistent retrograde filling of the left ICA aneurysm through the posterior communicating (PCOM) artery. Eventually, she was successfully treated with a flow diverter stent across the PCOM artery into the distal ICA. Follow up angiogram after 6 months showed patent flow in the PCOM artery and the distal ICA. with complete occlusion of the aneurysm. Using a flow diverter stent after insufficient parent vessel occlusion for giant intracranial aneurysms may be a feasible treatment option and an addition to the neurovascular treatment armamentarium.