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排序方式: 共有136条查询结果,搜索用时 15 毫秒
1.
Asim Muhammad Nabeel Ghani Muhammad Usman Ibrahim Muhammad Ali Mahmood Waqar Dengel Andreas Ahmed Sheraz 《Neural computing & applications》2021,33(11):5437-5469
Neural Computing and Applications - In order to provide benchmark performance for Urdu text document classification, the contribution of this paper is manifold. First, it provides a publicly... 相似文献
2.
Syed Waqar Haider Wouter C. Brink Neeraj Buch 《International Journal of Pavement Engineering》2017,18(7):645-657
The performance prediction models in the Pavement-ME design software are nationally calibrated using in-service pavement material properties, pavement structure, climate and truck loadings, and performance data obtained from the Long-Term Pavement Performance programme. The nationally calibrated models may not perform well if the inputs and performance data used to calibrate those do not represent the local design and construction practices. Therefore, before implementing the new M-E design procedure, each state highway agency (SHA) should evaluate how well the nationally calibrated performance models predict the measured field performance. The local calibrations of the Pavement-ME performance models are recommended to improve the performance prediction capabilities to reflect the unique conditions and design practices. During the local calibration process, the traditional calibration techniques (split sampling) may not necessarily provide adequate results when limited number of pavement sections are available. Consequently, there is a need to employ statistical and resampling methodologies that are more efficient and robust for model calibrations given the data related challenges encountered by SHAs. The main objectives of the paper are to demonstrate the local calibration of rigid pavement performance models and compare the calibration results based on different resampling techniques. The bootstrap is a non-parametric and robust resampling technique for estimating standard errors and confidence intervals of a statistic. The main advantage of bootstrapping is that model parameters estimation is possible without making distribution assumptions. This paper presents the use of bootstrapping and jackknifing to locally calibrate the transverse cracking and IRI performance models for newly constructed and rehabilitated rigid pavements. The results of the calibration show that the standard error of estimate and bias are lower compared to the traditional sampling methods. In addition, the validation statistics are similar to that of the locally calibrated model, especially for the IRI model, which indicates robustness of the local model coefficients. 相似文献
3.
Mixed Convection of Water at 4 °C Along a Wedge with Variable Surface Temperature in a Porous Medium
Waqar?A.?Khan Rama?Subba?Reddy?GorlaEmail author 《International Journal of Thermophysics》2011,32(10):2079-2091
In this study, the mixed convection of water at 4 °C along a wedge in a porous medium is investigated numerically using a
finite difference method. To explore the effect of mixed convection, both forced and free convection-dominated regimes are
considered. Non-similarity solutions are obtained for the variable walltemperature boundary condition. Velocity and temperature
profiles as well as local dimensionless skin friction and the Nusselt number are obtained and compared with available numerical
results for various values of different parameters. The wedge angle geometry parameter m and mixed convection parameter ξ ranged from 0 to 1 in both regimes, whereas different values of λ are considered for the purpose of comparison of heat transfer results. 相似文献
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Zahra Shabeh tu Syed Waqar A.A. Rafiq Nouman Shah Wiqar H. Iqbal Zafar 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(2):321-328
Protection of Metals and Physical Chemistry of Surfaces - Chromium oxide thin films were grown on Al2O3 substrates by ablating a pure Cr2O3 target using a KrF excimer laser. The energy density on... 相似文献
7.
Waqar Ahmad Ali Al-Matar Zaheer Aslam Izhar A. Malik Hafiz M. Irshad 《Chemical Engineering Communications》2020,207(7):946-960
AbstractA series of Cu-K/Al2O3 catalysts were synthesized by wet impregnation technique. The reduced catalysts were further used for conversion of carbon dioxide to methane and carbon monoxide. Moreover, the fresh and used catalysts were characterized to investigate the changes in the surface morphology, metal dispersion, surface area, crystalline phases, and functional groups of studied catalysts. The SEM analysis of fresh and spent catalysts showed no remarkable difference in surface morphology with irregular shaped agglomerated particles. Furthermore, TEM micrographs presented the well distribution of metal catalyst over alumina support. The decrease in surface area from 115 to 77?m2/g for Cu1.62-K0.5/Al2O3 after reaction was related to sintering and oxidation of catalyst during reaction. XRD revealed the disappearance of some minor peaks which can be associated with the sintering of spent catalyst. FTIR also presented some new peak for spent catalyst which can be linked with metal oxides. Moreover, various reaction conditions of temperature (230, 400, and 600?°C), pressure (1 and 7?bar), and feed molar ratio of H2/CO2 (2:1 and 4:1) were investigated using different Cu loading (0, 1, 1.25, 1.62, and 4 weight percent). A maximum CO2 conversion of 63% with 39% CH4 selectivity was achieved by using Cu1.62-K0.5/Al2O3 at 600?°C, molar ratio of H2/CO2 4 under 7?bar. The presence of K on the surface of synthesized catalyst increased the CO2 conversion from 48% (Cu1/Al2O3) to 55% (Cu1-K0.5/Al2O3) at above mentioned reaction conditions which suggested the promoter effect of K during conversion of carbon dioxide. 相似文献
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Lubna Sajjad Asaf Rahmatullah Jan Abdul Latif Khan Waqar Ahmad Saleem Asif Ahmed Al-Harrasi Kyung-Min Kim In-Jung Lee 《International journal of molecular sciences》2022,23(5)
The mechanism and course of Triticum plastome evolution is currently unknown; thus, it remains unclear how Triticum plastomes evolved during recent polyploidization. Here, we report the complete plastomes of two polyploid wheat species, Triticum sphaerococcum (AABBDD) and Triticum turgidum subsp. durum (AABB), and compare them with 19 available and complete Triticum plastomes to create the first map of genomic structural variation. Both T. sphaerococcum and T. turgidum subsp. durum plastomes were found to have a quadripartite structure, with plastome lengths of 134,531 bp and 134,015 bp, respectively. Furthermore, diploid (AA), tetraploid (AB, AG) and hexaploid (ABD, AGAm) Triticum species plastomes displayed a conserved gene content and commonly harbored an identical set of annotated unique genes. Overall, there was a positive correlation between the number of repeats and plastome size. In all plastomes, the number of tandem repeats was higher than the number of palindromic and forward repeats. We constructed a Triticum phylogeny based on the complete plastomes and 42 shared genes from 71 plastomes. We estimated the divergence of Hordeum vulgare from wheat around 11.04–11.9 million years ago (mya) using a well-resolved plastome tree. Similarly, Sitopsis species diverged 2.8–2.9 mya before Triticum urartu (AA) and Triticum monococcum (AA). Aegilops speltoides was shown to be the maternal donor of polyploid wheat genomes and diverged ~0.2–0.9 mya. The phylogeny and divergence time estimates presented here can act as a reference framework for future studies of Triticum evolution. 相似文献
10.
Z. Waqar 《Journal of Materials Science》2007,42(4):1169-1176
Studies of Atomic Hydrogen accumulation in highly oriented pyrolytical graphite (HOPG) have been performed using scanning
tunnelling microscope (STM) and atomic force microscope (AFM). It is found that after intercalation atomic hydrogen is stored
among graphene layers in H2 gas form, captured inside graphene blisters. On desorption of hydrogen, some lateral etching of upper graphene layers takes
place. Significant information about intake, retention and possibility of manifold accumulation of hydrogen in HOPG has been
found. 相似文献