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1.
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   
2.
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   
3.
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   
4.
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   
5.
6.
The sequestration of calcium by polyphosphates in the presence of oxalate as a precipitating agent is reported at 25 and 60C in the pH range of 5–12. Sequestration increased with temperature. The sensitivity of sequestration to pH changes decreased with increase in the chain length of the polyphosphates. Magnesium sequestration by polyphosphates in the presence of sodium oleate is given at pH values of 10.5 and 9.0. In dilute solution with pH values higher than 9.5, tripolyphosphate and pyrophosphate were found to be the most effective calcium and magnesium polyphosphate sequestrants on a weight basis, respectively. The results are discussed from a semi-theoretical viewpoint.  相似文献   
7.
Semiconductors - Abstract—Our work reports on the influence of etching modes and their combination on the design, microstructural and optical properties of compliant substrates based on...  相似文献   
8.
In this paper, the effect of reinforcement corrosion and loss of concrete cover on structural behavior of bridge columns is quantified by developing moment–axial load (M–P) interaction diagrams using modified analysis procedure and advanced deteriorated material models. The results of this study suggest that corrosion of steel bars on the compression side of column section reduces the effective depth, and causing more reduction than left side or tension side deterioration, in compression controlled region. However, in general, corrosion of tension reinforcement causes more strength reduction than corrosion of reinforcement in compression or left/right side reinforcement, particularly, in tension controlled region.  相似文献   
9.
In the past decade, the use of marine mussels as seafood is being more popular. They considered being a rich source of various nutritional bioactive compounds that aroused the scientific community's interest. This study investigated the antioxidant and the antithrombotic consequences on Sprague-Dawley male rats after adding dried New Zealand mussel Perna canaliculus in their diet. The biochemical, hematological and histopathological changes were also observed. Forty rats were divided into four groups according to the amount of dried mussels in their diet, in addition to a control group that consumed a basal diet only. Group 1 consumed 25% dried mussels in its basal diet; Group 2 consumed 35% dried mussels in its basal diet, and Group 3 was consumed 45% dried mussels in its basal diet. The biochemical parameters showed improvements in liver function. Interestingly, the lipid profile decreased, especially the low-density lipoprotein cholesterol (LDL-C) levels which were reduced significantly in Group 3 (p < .01). These observations were accompanied by a decrease in iron levels significantly as the amount of dried mussels increased (p < .01). Furthermore, the noticed changes in the hematological profile prove that there is an increase in antithrombotic activity. Dried mussels had potent antioxidant effects in the liver as shown by increased lipid peroxide (p < .05), reduced glutathione (p < .05), and glutathione peroxidase (GSH-Px; p < .05). Additionally, antioxidant activity in the kidney was shown to increase through GSH-Px activity (p < .01). In conclusion, these results indicate that consuming dried mussels resulted in improved biochemical and antioxidants activities and could be used as an antithrombotic agent.  相似文献   
10.
Cutaneous leishmaniasis in Morocco occurs mainly in the south and is caused by Leishmania major and L. tropica. In 1995, for the first time, 4 autochthonous cases were confirmed by smear and/or culture from the province of Taza in north Morocco. An active survey revealed 128 more cases. The number had increased gradually since 1994. Most of the cases (86%) came from the suburbs of the city of Taza. All cultured and typed parasites were characterized as L. tropica MON-102. A leishmanin skin test survey among a random sample of the exposed population showed an overall positivity rate of 19.9%, with no correlation with age or gender. The spatial distribution of the cases and skin test positivity, their occurrence in all age groups, the highly variable clinical picture, the severity and large size of lesions in older patients, the slow recovery of some treated patients, and the isoenzymic monomorphism of the parasite, all suggested that cutaneous leishmaniasis caused by L. tropica is an emerging disease in Taza.  相似文献   
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