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Abouelnaga Amal M. Meaz Talaat M. Othman Abdelmageed M. Ghazy Riyad A. El Nahrawy Amany M. 《SILICON》2021,13(3):623-631
Silicon - The nature of the opening silicate- based surface affects the chemical interaction, spectroscopic and antimicrobial efficiency. The aim of this approach was to evaluate the spectroscopic... 相似文献
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Timothy Dube Onisimo Mutanga Elfatih M. Abdel-Rahman Riyad Ismail Rob Slotow 《International journal of remote sensing》2013,34(14):3751-3772
Accurate, reliable, and up-to-date forest stand volume information is a prerequisite for a detailed evaluation of commercial forest resources and their sustainable management. Commercial forest responses to global climate change remain uncertain, and hence the mapping of stand volume as carbon sinks is fundamentally important in understanding the role of forests in stabilizing climate change effects. The aim of this study was to examine the utility of stochastic gradient boosting (SGB) and multi-source data to predict stand volume of a Eucalyptus plantation in South Africa. The SGB ensemble, random forest (RF), and stepwise multiple-linear regression (SMLR) were used to predict Eucalyptus stand volume and other related tree-structural attributes such as mean tree height and mean diameter at breast height (DBH). Multi-source data consisted of SPOT-5 raw spectral features (four bands), 14 spectral vegetation indices, rainfall data, and stand age. When all variables were used, the SGB algorithm showed that stand volume can be accurately estimated (R2 = 0.78 and RMSE = 33.16 m3 ha?1 (23.01% of the mean)). The competing RF ensemble produced an R2 value of 0.76 and a RMSE value of 37.28 m3 ha?1 (38.28% of the mean). SMLR on the other hand, produced an R2 value of 0.65 and an RMSE value of 42.50 m3 ha?1 (42.50% of the mean). Our study further showed that Eucalyptus mean tree height (R2 = 0.83 and RMSE = 1.63 m (9.08% of the mean)) and mean diameter at breast height (R2 = 0.74 and RMSE = 1.06 (7.89% of the mean)) can also be reasonably predicted using SGB and multi-source data. Furthermore, when the most important SGB model-selected variables were used for prediction, the predictive accuracies improved significantly for mean DBH (R2 = 0.81 and RMSE = 1.21 cm (6.12% of the mean)), mean tree height (R2 = 0.86 and RMSE = 1.39 m (7.02% of the mean)), and stand volume (R2 = 0.83 and RMSE = 29.58 m3 ha?1 (17.63% of the mean)). These results underscore the importance of integrating multi-source data with remotely sensed data for predicting Eucalyptus stand volume and related tree-structural attributes. 相似文献
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Sarah Abduljabbar Yaseen Ghadah Abdaljabar Yiseen Chi Sun Poon Christopher K. Leung Zongjin Li 《Journal of the American Ceramic Society》2023,106(8):4967-4986
The current work scrutinizes the effectuation of seawater on morphological properties, pore structure, and compressive strength during the hydration process of fly ash blended cement at 3, 7, 28, 56, and 90 days to better understand the influence of salinity conditions of seawater on the microstructural modification and strength development of the hydration products as well as the total porosity. The chemical reaction's mechanism of mightily soluble salts, for example, Mg2SO4 and NaCl, with hydrated fly ash and blended cement (calcium-bearing phases) was also confirmed. Fourier-transform infrared spectroscopy has been appointed to observe and characterize the energetics of variation in the formulation of portlandite (CH), calcium silicate hydrate, gypsum (Gy), ettringite (AFt), and calcium chloroaluminate (Friedel's salt [FS]) throughout the hydration process of fly ash blended cement with seawater in comparison with deionized water. X-ray diffraction analysis exposed that the peak intensities of FS, portlandite, and some particular phases of the hydrated fly ash blended cement in seawater are higher and sharper than the comparable peaks in deionized water. Mercury intrusion porosimetry-measurements have been appointed that the total porosity of artificial seawater (ASW) was decreased from 28.9% at 3 days to 19.4% at 56 days. In addition, the average, median, and critical pore diameter were decreased in ASW while compared to deionized water (DIW). The reaction products of this work were also characterized using scanning electron microscopy, EDS, compressive strength, and isothermal calorimeter. 相似文献
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AIMS: Progressive loss of neuroretinal rim tissue is known to occur early in glaucoma and measurement of the neuroretinal rim area is possible by magnification corrected analysis of optic disc photographs (planimetry). This study was performed to determine whether the facility to distinguish between glaucomatous and normal optic discs could be improved upon by: (a) taking into account the known relation between optic disc size and neuroretinal rim area, and (b) measuring rim area in a number of segments, in order to detect focal changes. METHODS: Planimetric examination of the optic disc photographs of 88 control subjects and 51 patients with early visual field defects was performed. In the control group, multiple linear regression analysis was performed between neuroretinal rim area and optic disc area, age, sex, eye side, refraction, and keratometry. This was repeated for the whole disc and for each of twelve 30 degree segments. Normal ranges were defined by the 98% prediction intervals of the regression analysis and the sensitivity and specificity for correct identification of optic discs in the two groups determined. RESULTS: Multiple linear regression demonstrated significant associations between the neuroretinal rim area and optic disc area and age in normal subjects. Sensitivity and specificity for glaucoma diagnosis, using the cut off derived from the 98% prediction intervals, was 37.7% and 98.9% respectively when total neuroretinal rim area alone was considered, and 88.7% and 94.3% respectively when the 30 degree segments were included. The most frequent pattern of neuroretinal rim loss was diffuse, followed by thinning in more than one sector and then by thinning in the inferotemporal sector alone. CONCLUSIONS: This method of optic disc analysis enables the examiner to identify glaucomatous optic discs at the stage of early perimetric loss with a high degree of precision. Optic disc photography is simple, and fundus cameras are widely available. This method for glaucoma case identification may therefore be suitable for the primary care setting as well as hospital practice. 相似文献
5.
Strength Evaluation of Deteriorated RC Bridge Columns 总被引:1,自引:0,他引:1
Condition-rating methods followed by load rating calculations are used for evaluating existing bridges in the United States. Ratings are assessed visually based on engineering expertise and experience, and in some cases supplemented by nondestructive tests. Good understanding of the effects of deterioration on the structural performance leads to better inspection procedures, planning, and cost-effective rehabilitation methods. This paper presents a bridge pier column strength evaluation method that can be adapted into a currently used bridge condition evaluation method. This method uses damaged material properties, and accounts for amount of corrosion and exposed bar length for each reinforcement, concrete loss, bond failure, and type of stresses in the corroding reinforcement. The proposed evaluation method provides a good estimate of the condition and load-carrying capacity of bridge piers that currently cannot be obtained by normal visual surveys. In addition, the proposed evaluation approach will help reduce repair costs, avoid overconservative condition ratings, and result in a more uniform level of safety of concrete bridge substructure in the United States. 相似文献
6.
Abduljabbar Dhuha Abdulhadi Hashim Siti Zaiton Mohd Sallehuddin Roselina 《Telecommunication Systems》2020,74(2):225-252
Telecommunication Systems - Over the past couple of decades, the research area of network community detection has seen substantial growth in popularity, leading to a wide range of researches in the... 相似文献
7.
The performance characteristics of vehicle suspension systems based on two alternative forms of control law are studied, evaluated, and compared with those of the pertinent semi-active counterparts and passive suspension systems. A two-dimensional four degree-of-freedom linear vehicle model, subjected to random roadway irregularities, is adopted. Time delays inherent in the feedback loops are included. The particular combinations of state variable values of interest are derived using linear optimal control theory for both active and semi-active systems. 相似文献
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Md. Riyad Tanshen ;Sinil Lee ;Junhyo Kim ;Donghoon Kang ;Jungpil Noh ;HanShik Chung ;HyoMin Jeong ;Sunchul Huh 《中南工业大学学报(英文版)》2014,(6):2341-2348
Effective thermal performance of oscillating heat pipe (OHP) is driven by inside pressure distribution. Heat transfer phenomena were reported in terms of pressure and frequency of pressure fluctuation in multi loop OHP charged with aqueous Al2O3 and MWCNTs/Al2O3 nanoparticles. The influences on thermal resistance of aqueous Al2O3, MWCNTs as well as the hybrid of them in OHP having 3 mm in inner diameter were investigated at 60% filling ratio. Experimental results show that thermal characteristics are significantly inter-related with pressure distribution and strongly depend upon the number of pressure fluctuations with time. Frequency of pressure depends upon the power input in evaporative section. A little inclusion of MWCNTs into aqueous Al2O3 at 60% filling ratio achieves the highest fluctuation frequency and the lowest thermal resistance at any evaporator power input though different nanofluids cause different thermal performances of OHPs. 相似文献
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Nada Sadoon Ahmedzeki Haider Abdulkarem Rashid Asir Abduljabbar Alnaama Maha Hadi Alhasani Zainab Abdulhussain 《Korean Journal of Chemical Engineering》2013,30(12):2213-2218
Adsorption techniques are widely used to remove certain classes of pollutants from wastewater. Phenolic compounds represent one of the problematic groups. Na-Y zeolite has been synthesized from locally available Iraqi kaolin clay. Characterization of the prepared zeolite was made by XRD and surface area measurement using N2 adsorption. Both synthetic Na-Y zeolite and kaolin clay have been tested for adsorption of 4-Nitro-phenol in batch mode experiments. Maximum removal efficiencies of 90% and 80% were obtained using the prepared zeolite and kaolin clay, respectively. Kinetics and equilibrium adsorption isotherms were investigated. Investigations showed that both Langmuir and Freundlich isotherms fit the experimental data quite well. On the other hand, the adsorption of phenol was found to obey first-order kinetics. 相似文献