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Muhannad A. Abbasi,Allison M. Blake,Roberto Sarnari,Daniel Lee,Allen S. Anderson,Kambiz Ghafourian,Sadiya S. Khan,Esther E. Vorovich,Jonathan D. Rich,Jane E. Wilcox,Clyde W. Yancy,James C. Carr,Michae 한국심초음파학회 2022 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.30 No.4
BACKGROUND: Cardiac allograft vasculopathy (CAV) is a complication beyond the first-year post-heart transplantation (HTx). We aimed to test the utility of cardiac magnetic resonance (CMR) to detect functional/structural changes in HTx recipients with CAV. METHODS: Seventy-seven prospectively recruited HTx recipients beyond the first-year post-HTx and 18 healthy controls underwent CMR, including cine imaging of ventricular function and T1- and T2-mapping to assess myocardial tissue changes. Data analysis included quantification of global cardiac function and regional T2, T1 and extracellular volume based on the 16-segment model. International Society for Heart and Lung Transplantation criteria was used to adjudicate CAV grade (0–3) based on coronary angiography. RESULTS: The majority of HTx recipients (73%) presented with CAV (1: n = 42, 2/3: n = 14, 0: n = 21). Global and segmental T2 (49.5 ± 3.4 ms vs 50.6 ± 3.4 ms, p < 0.001;16/16 segments) were significantly elevated in CAV-0 compared to controls. When comparing CAV-2/3 to CAV-1, global and segmental T2 were significantly increased (53.6 ± 3.2 ms vs. 50.6 ± 2.9 ms, p < 0.001; 16/16 segments) and left ventricular ejection fraction was significantly decreased (54 ± 9% vs. 59 ± 9%, p < 0.05). No global, structural, or functional differences were seen between CAV-0 and CAV-1. CONCLUSIONS: Transplanted hearts display functional and structural alteration compared to native hearts, even in those without evidence of macrovasculopathy (CAV-0). In addition, CMR tissue parameters were sensitive to changes in CAV-1 vs. 2/3 (mild vs. moderate/severe). Further studies are warranted to evaluate the diagnostic value of CMR for the detection and classification of CAV.
Seismic lateral earth pressure analysis of retaining walls
Ismeik, Muhannad,Shaqour, Fathi Techno-Press 2015 Geomechanics & engineering Vol.8 No.4
Based on limit equilibrium principles, this study presents a theoretical derivation of a new analytical formulation for estimating magnitude and lateral earth pressure distribution on a retaining wall subjected to seismic loads. The proposed solution accounts for failure wedge inclination, unit weight and friction angle of backfill soil, wall roughness, and horizontal and vertical seismic ground accelerations. The current analysis predicts a nonlinear lateral earth pressure variation along the wall with and without seismic loads. A parametric study is conducted to examine the influence of various parameters on lateral earth pressure distribution. Findings reveal that lateral earth pressure increases with the increase of horizontal ground acceleration while it decreases with the increase of vertical ground acceleration. Compared to classical theory, the position of resultant lateral earth force is located at a higher distance from wall base which in turn has a direct impact on wall stability and economy. A numerical example is presented to illustrate the computations of lateral earth pressure distribution based on the suggested analytical method.
Alsheikhy, Ahmed,Almutiry, Muhannad International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.3
The radar tomographic imaging is based on the Radar Cross-Section "RCS" of the materials of a shape under examination and investigation. The RCS varies as the conductivity and permittivity of a target, where the target has a different material profile than other background objects in a scene. In this research paper, we use Hierarchical Performance Modeling "HPM" and a framework developed earlier to determine/spot bottleneck(s) for pattern recognition of materials using a combination of the Single Layer Perceptron (SLP) technique and tomographic images in radar systems. HPM provides mathematical equations which create Objective Functions "OFs" to find an average performance metric such as throughput or response time. Herein, response time is used as the performance metric and during the estimation of it, bottlenecks are found with the help of OFs. The obtained results indicate that processing images consumes around 90% of the execution time.
Ahmed M. Ashteyat,Muhannad Ismeik 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.1
Artificial neural network models can be successfully used to simulate the complex behavior of many problems in civil engineering. As compared to conventional computational methods, this popular modeling technique is powerful when the relationship between system parameters is intrinsically nonlinear, or cannot be explicitly identified, as in the case of concrete behavior. In this investigation, an artificial neural network model was developed to assess the residual compressive strength of self-compacted concrete at elevated temperatures (20-900oC) and various relative humidity conditions (28-99%). A total of 332 experimental datasets, collected from available literature, were used for model calibration and verification. Data used in model development incorporated concrete ingredients, filler and fiber types, and environmental conditions. Based on the feed-forward back propagation algorithm, systematic analyses were performed to improve the accuracy of prediction and determine the most appropriate network topology. Training, testing, and validation results indicated that residual compressive strength of selfcompacted concrete, exposed to high temperatures and relative humidity levels, could be estimated precisely with the suggested model. As illustrated by statistical indices, the reliability between experimental and predicted results was excellent. With new ingredients and different environmental conditions, the proposed model is an efficient approach to estimate the residual compressive strength of self-compacted concrete as a substitute for sophisticated laboratory procedures.
Prediction of Microstructure for AISI316L Steel from Numerical Simulation of Laser Powder Bed Fusion
Maria Beatrice Abrami,Marialaura Tocci,Muhannad Ahmed Obeidi,Dermot Brabazon,Annalisa Pola 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.11
Laser powder bed fusion (L-PBF) success in the industrial scenario strongly depends on the ability to manufacture componentswithout defects and with high building rates, but also on the ability to effectively control the microstructure to gain therequired properties in the final component. In this regard, the recently developed numerical simulation software of L-PBFtechnologies can represent an effective tool, since many of them provide solidification data (i.e. temperature gradient andcooling rate) useful for microstructure prediction. In this work, a numerical model was applied to simulate the processingof four single scan tracks of 316L stainless steel processed with different parameters. Temperature and cooling rate aroundthe melt pool were extracted from the numerical model and used to estimate the microstructure cellular arm spacing and themicrohardness. Experimental measurements were then compared with the estimated values revealing good agreement. Thegood agreement between experimental and estimated values shows the advantages of the proposed method for microstructureand microhardness prediction based on numerical modelling as a useful resource for process optimization according to therequired final microstructural features.
Khalil Ruhul Amin,Saeed Nasir,Almutiry Muhannad,Alenezi Ali Hamdan 한국통신학회 2023 ICT Express Vol.9 No.5
The Industrial Internet of Things (IIoT) necessitates low-latency and ultra-reliable communication to support various applications. Besides, the data generated in IIoT must be geo-tagged to take location-aware timely actions. Therefore, this paper proposes an accurate and energy-efficient localization scheme for localizing the devices in IIoT. We introduce a novel anchor activation protocol for the non-cooperative localization of IIoT devices. The proposed method is sequential, distributed, and error adaptive, that first performs distributed scheduling followed by adaptive selection. This distributed localization scheme is well-suited for IIoT due to the non-cooperative nature of the devices; however, at the same time, it is more challenging because no centralized node can disseminate the anchors’ network information. Therefore, the anchors rely only on the local information from other anchors in their vicinity. The distributed approach can significantly benefit such networks because the centralized node can be a system’s bottleneck. Besides the distributed nature, the decision process of anchor selection for localization considers the transmission energy of the anchors to make it energy efficient. Our results show the effectiveness of the proposed method both in terms of localization accuracy and energy efficiency.
UAVs-assisted passive source localization using robust TDOA ranging for search and rescue
Ruhul Amin Khalil,Nasir Saeed,Muhannad Almutiry 한국통신학회 2023 ICT Express Vol.9 No.4
Mobile connections and applications are growing unprecedentedly with the advent and increasing popularity of wireless services worldwide, which greatly increases the demands on data traffic. This led to considering millimeter-wave bands and ultra-dense deployment as part of the key enabler solutions in 5G networks. However, these solutions radically increase the number of handovers (HOs), thus increasing the rate of unnecessary HO and dropping call probabilities. In this regard, optimizing HO control parameters appropriately is the main factor that can efficiently address HO issues during user mobility. This paper proposes a fuzzy-coordinated self-optimizing HO scheme to achieve a seamless HO while users move in multi-radio access networks. The proposed scheme resolves the conflict between mobility robustness and load balancing functions by utilizing a fuzzy system considering three input parameters: signal-to-interference-plus-noise ratio, cell load and UE speed. Simulation results show that the proposed scheme manages to control the mobility optimization in terms of ping-pong HO, radio link failure and HO latency over different mobile speed scenarios. Moreover, the proposed scheme reduces the outage probability compared to other schemes from literature.
Mohammed A. Rashaideh,Kristi E. Janho,Muhannad Jalokh,Eyad S. Ajarmeh,Mohammed As’ad 대한혈관외과학회 2019 Vascular Specialist International Vol.35 No.3
Behçet’s disease (BD) is a multisystemic, chronic autoimmune inflammatory vasculitic disease with an unknown etiology. Although the literature reports that vascular involvement occurs in 7% to 38% of all BD cases, the arteries are rarely involved; however, arterial involvement is usually associated with significant mortality and morbidity. We report the case of a young female patient who presented to the emergency department with severe abdominal pain and a history of weight loss. The patient was evaluated using computed tomography angiography, which revealed a ruptured suprarenal aortic pseudoaneurysm with occlusion of both the superior mesenteric and celiac arteries. Urgent surgery was performed with aortic repair with an interposition graft and superior mesenteric artery embolectomy. The patient’s clinical history and radiological imaging findings were strongly suggestive of the diagnosis of BD with vascular involvement.