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Machine learning based models for predicting compressive strength of geopolymer concrete

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1028-1049页

作者： Quang-huy LE Duy-hung NGUYEN Thanh SANG-TO samir KhATIR hoang LE-MINh Amir h.GANDOMI Thanh CUONG-LE Center for Engineering Application and Technology Solutions Ho Chi Minh City Open UniversityHo Chi Minh 700000Vietnam Institute of Civil Engineering Ho Chi Minh City University of TransportHo Chi Minh 700000Vietnam Faculty of Engineering&Information Technology University of Technology SydneyUltimoNSW 2007Australia

Recently,great attention has been paid to geopolymer concrete due to its advantageous mechanical and environmentally friendly *** effort has been made in experimental studies to advance the understanding of geopolymer concrete,in which compressive strength is one of the most important *** facilitate engineering work on the material,an efficient predicting model is *** this study,three machine learning(ML)-based models,namely deep neural network(DNN),K-nearest neighbors(KNN),and support vector machines(SVM),are developed for forecasting the compressive strength of the geopolymer concrete.A total of 375 experimental samples are collected from the literature to build a database for the development of the predicting models.A careful procedure for data preprocessing is implemented,by which outliers are examined and removed from the database and input variables are standardized before feeding to the fitting *** standard K-fold cross-validation approach is applied for evaluating the performance of the models so that overfitting status is well managed,thus the generalizability of the models is *** effectiveness of the models is assessed via statistical metrics including root mean squared error(RMSE),mean absolute error(MAE),correlation coefficient(R),and the recently proposed performance index(PI).The basic mean square error(MSE)is used as the loss function to be minimized during the model fitting *** three ML-based models are successfully developed for estimating the compressive strength,for which good correlations between the predicted and the true values are obtained for DNN,KNN,and *** numerical results suggest that the DNN model generally outperforms the other two models.

关键词： geopolymer concrete compressive strength prediction machine-learning based model deep neural network K-nearest neighbor support vector machines

Manipulating Nb-doped SrFeO_(3−δ)with excellent performance for proton-conducting solid oxide fuel cells

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Journal of Advanced Ceramics 2024年第5期13卷 579-589页

作者： hailu Dai hongzhe Du samir Boulfrad Shoufu Yu Lei Bi Qinfang Zhang School of Materials Science and Engineering Yancheng Institute of TechnologyYancheng 224051China College of Science&Engineering Hamad Bin Khalifa UniversityDoha 34110Qatar School of Resource Environment and Safety Engineering University of South ChinaHengyang 421001China

Nb-doped SrFeO_(3−δ)(SFO)is used as a cathode in proton-conducting solid oxide fuel cells(h-SOFCs).First-principles calculations show that the SrFe0.9Nb0.1O_(3−δ)(SFNO)cathode has a lower energy barrier in the cathode reaction for h-SOFCs than the Nb-free SrFeO_(3−δ)*** experimental studies show that Nb doping substantially enhances the performance of the SrFeO_(3−δ)***,oxygen vacancies(VO)were introduced into SFNO using the microwave sintering method,further improving the performance of the SFNO *** mechanism behind the performance improvement owing to VO was revealed using first-principles calculations,with further optimization of the SFNO cathode achieved by developing a suitable wet chemical synthesis route to prepare nanosized SFNO *** method significantly reduces the grain size of SFNO compared with the conventional solid-state reaction method,although the solid-state reaction method is generally used for preparing Nb-containing *** a result of defect engineering and synthesis approaches,the SFNO cathode achieved an attractive fuel cell performance,attaining an output of 1764 mW·cm−2 at 700℃ and operating for more than 200 *** manipulation of Nb-doped SrFeO_(3−δ)can be seen as a“one stone,two birds”strategy,enhancing cathode performance while retaining good stability,thus providing an interesting approach for constructing high-performance cathodes for h-SOFCs.

关键词： SrFeO_(3−δ)-(SFO) cathode proton conductor solid oxide fuel cells(SOFCs)

Controlled Synthesis of Bismuth Oxyhalides-based Nanomaterials and Their Catalytic Applications

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Controlled Synthesis of Bismuth Oxyhalides-based Nanomateria...

作者： Ahmad samir Karimi haqmal 北京化工大学

学位级别：硕士

卤氧化铋(BiOX,X=Cl、Br或I)因其独特的结构特性,如二维层状结构和大量暴露的表面原子,而受到广泛关注。这些特性使它们成高效的光催化剂,并被广泛应用于水处理、有机合成等领域。然而,它们在其他催化中的潜力,如作为金属铋的前体或作... 详细信息

卤氧化铋(BiOX,X=Cl、Br或I)因其独特的结构特性,如二维层状结构和大量暴露的表面原子,而受到广泛关注。这些特性使它们成高效的光催化剂,并被广泛应用于水处理、有机合成等领域。然而,它们在其他催化中的潜力,如作为金属铋的前体或作为单原子催化剂的载体,还处于起步阶段。在本论文中,我们研究了卤素离子和形貌对以卤氧化铋为前驱体合成的金属铋电催化剂的结构的影响,及其在氮还原反应(NRR)中的性能,并以氯氧化铋为载体制备了 Pt单原子催化剂,探究了其在苯乙炔反马仕加成硅氢化反应中的催化性能。本论文取得的主要研究成果如下:在第一个工作中,我们发展了一种电还原卤氧化铋制备的金属铋纳米片(BNSs)的合成方法,并将其应用于电催化氮还原反应(NRR)。BNSs可分别由具有不同卤素离子的卤氧化铋纳米片前体以及溴氧化铋纳米棒制备的。X射线衍射(XRD)表征结果显示成功形成了铋纳米片,而电子显微镜表明,以溴氧化铋纳米棒为前驱体制备的BNS1尺寸在70-120纳米之间,以溴氧化铋纳米片为前驱体制备的BNS2尺寸在150-200 nm之间。值得注意的是,在环境温度下,在0.1M Na2SO4水溶液中,在-0.6 VvsRhE时,BNS2的氨产率和法拉第效率分别为3.99 μ gNh3 mgBi-1 h-1和7.04%,而 BNS1 则分别为 2.52 μ gNh3 mgBi-1 h-1 和 4.93%。在第二个工作中,我们采用光沉积策略制备了沉积在氯氧化铋纳米片上的铂单原子催化剂(PtxBOC SAC,该催化剂在苯乙炔的反马氏硅氢化加成反应中表现出优异的催化性能。我们首先合成了氯化氧铋纳米片,然后通过光沉积方法沉积了铂单原子。透射电子显微镜、X射线衍射、X射线光电子能谱、能量色散X射线光谱和CO吸收红外光谱结果表明,铂以单原子的形式均匀分布在氯氧化铋纳米片上。电感耦合等离子体质谱结果表明,铂单原子催化剂的铂负载量在0.5 wt%-4.0 wt%范围内。其中,Pt1BOC在苯乙炔的反马氏氢化硅烷化反应中表现出最高的催化性能,转化频率为156 min-1。该值远高于铂纳米颗粒对比样,也高于文献报道的值。此外,该催化剂表现出优异的稳定性,在5个循环后催化性能没有明显衰减。

关键词：卤氧化铋氮还原反应光沉积单原子催化剂反马尔可夫尼科夫氢硅化化反应

Oscillation of third-order functional dynamic equations on time scales

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Science China Mathematics 2011年第12期54卷 2597-2614页

作者： saker samir h. College of Science Research Centre King Saud University P.O. Box 2455 Riyadh 11451 Saudi Arabia

We consider the nonlinear functional dynamic equation (p(t)[(r(t)xΔ (t))Δ]γ )Δ + q(t)f (x(τ (t))) = 0, for t≥t0, on a time scale T, where γ > 0 is the quotient of odd positive integers, p, r, τ and q are positive rd-continuous functions defined on the time scale T, and limt→∞τ (t) = ∞. The main aim of this paper is to establish some new sufficient conditions which guarantee that the equation has oscillatory solutions or the solutions tend to zero as t →∞. The main investigation depends on the Riccati substitution and the analysis of the associated Riccati dynamic inequality. Our results extend, complement and improve some previously obtained ones. In particular, the results provided substantial improvement for those obtained by Yu and Wang [J Comput Appl Math, 225 (2009), 531-540]. Some examples illustrating the main results are given.531–540]. Some examples illustrating the main results are given.

关键词：时间尺度动态方程振荡非线性动力学方程 Riccati 三阶连续函数正整数

Interval oscillation criteria for forced Emden-Fowler functional dynamic equations with oscillatory potential

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Science China Mathematics 2013年第3期56卷 561-576页

作者： ANDERSON Douglas R. saker samir h. Department of Mathematics and Computer Science Concordia College Department of Mathematics Faculty of Science Mansoura University

Interval oscillation criteria are established for a second-order functional dynamic equation of Emden-Fowler type with oscillatory potential by applying Riccati and generalized Riccati techniques. The results represent further improvements on those given even for differential and difference equations. Some examples are considered to illustrate the main results.

关键词：区间振动准则动态方程线性 Riccati 电位振荡差分方程黎卡提

Comments on process of duplex coatings on aluminum alloys

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Journal of Central South University of Technology 2004年第3期11卷 239-245页

作者： samir h.A. 钱翰城夏伯才吴仕明 School of Mechanical Engineering Chongqing University Chongqing 400044 China

Despite the great achievements made in improvement of wear resistance properties of aluminum alloys, their applications in heavy surface load-bearing are limited. Single coating is insufficient to produce the desired combination of surface properties. These problems can be solved through the duplex coatings. The aim of the present study is to overview the research advances on processes of duplex coatings on (aluminum) alloys combined with micro plasma oxidation process and with other modern processes such as physical vapour deposition and plasma assisted chemical vapour deposition and also to evaluate the performance of micro plasma oxidation coatings in improving the load-bearing, friction and wear resistance properties of aluminum alloys in comparison with other coatings. Wherein, a more detailed presentation of the processes and their performances and disadvantages are given as well.

关键词：铝合金金属腐蚀微量等离子氧化摩擦学

Alcohol,inflammation,and gut-liver-brain interactions in tissue damage and disease development

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World Journal of Gastroenterology 2010年第11期16卷 1304-1313页

作者： h Joe Wang samir Zakhari M Katherine Jung Division of Metabolism and health Effects National Institute on Alcohol Abuse and Alcoholism National Institutes of Health

Chronic inflammation is often associated with alcoholrelated medical conditions. The key inducer of such inflammation, and also the best understood, is gut microflora-derived lipopolysaccharide (LPS). Alcohol can significantly increase the translocation of LPS from the gut. In healthy individuals, the adverse effects of LPS are kept in check by the actions and interactions of multiple organs. The liver plays a central role in detoxifying LPS and producing a balanced cytokine milieu. The central nervous system contributes to anti-inflammatory regulation through neuroimmunoendocrine actions. Chronic alcohol use impairs not only gut and liver functions, but also multi-organ interactions, leading to persistent systemic inflammation and ultimately, to organ damage. The study of these interactions may provide potential new targets for therapeutic intervention.

关键词： Chronic alcohol use Chronic inflammation Li- popolysaccharides Pro-inflammatory and anti-inflammatory cytokines Kupffer cells Monocytes Tumor necrosis factor α Interleukin-10 Neuroendocrine hypothalamo-pituitary-adrenal axis Glucocorticoid

Overactivation of histone deacetylases and EZh2 in Wilms tumorigenesis

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Genes & Diseases 2023年第5期10卷 1783-1786页

作者： Chao-hui Chen Nguyen Yen Nhi Ngo Alun Wang samir El-Dahr hongbing Liu Department of Pediatrics Tulane University School of MedicineNew OrleansLA 70112USA Department of Pathology and Laboratory Medicine Tulane University School of MedicineNew OrleansLA 70112USA

Wilms tumor (WT) is the most common childhood kidney cancer. Although WT is largely curable, current treatments fail in up to 15 percent of patients. Moreover, survivors suffer from the complications and late effects of the aggressive treatments. Thus, there is a critical need to improve our understanding of tumorigenesis to develop novel therapies to reduce the treatment burden while maintaining excellent survival rates. WT is believed to arise from the immature kidney cells, nephron progenitor cells (NPCs), which have failed to differentiate properly. Previous studies revealed that Wilms cells share a transcriptional and epigenetic landscape with normal renal stem cells.1 Although several studies have shown the positive associations between WT in children and embryonic exposure to adverse environments, the underlying mechanisms remain unknown. Altered epigenetics is central to oncogenesis in many pediatric cancers. The critical contribution of epigenetic dysregulation to pediatric tumors provides a compelling rationale for the therapeutic potential of epigenetic drugs. histone deacetylases (hDACs) and Enhancer of Zeste homolog 2 (EZh2, a histone h3K27 methyltransferase), have been demonstrated to play a critical role in self-renewal and differentiation of mouse NPCs.2,3 In addition, altered expression and mutations of hDACs and EZh2 have been linked to many human cancers, including WT. Thus, they are among the most promising therapeutic targets for cancer treatment. We reasoned that WT would result from the unrestrained proliferation of progenitor cells due to overactive hDAC1/2 (hDAC1 and hDAC2), and EZh2. We tested this hypothesis by analyzing a clinical specimen received from the left kidney tumor of an 11-year-old male patient diagnosed with WT and four other human WT specimens. We have the approval from Tulane human Research Protection Office & Institutional Review Boards (Study number: 2019–623) to study WT specimens. The tumor (9.5 cm × 8 cm × 7.5 cm) is cl

关键词： EZh2 Figure approval

Stabilization and Synchronization of Discrete-time Fractional Chaotic Systems with Non-identical Dimensions

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Acta Mathematicae Applicatae Sinica 2021年第3期37卷 523-538页

作者： samir BENDOUKhA Department of Electrical Engineering College of EngineeringYanbuTaibah UniversitySaudi Arabia

This paper investigates the stabilization and synchronization of two fractional chaotic maps proposed recently,namely the 2D fractional hénon map and the 3D fractional generalized hénon *** show that although these maps have non–identical dimensions,their synchronization is still *** proposed controllers are evaluated experimentally in the case of non–identical orders or time–varying *** methods are used to illustrate the results.

关键词： discrete chaos fractional discrete calculus hénon based maps stabilization synchronization