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A Study on Pullout Test of Root Subjected to Axial Load Полный текст
2020
Lun Zhang, Zhenyao Xia, Wennian Xu, Xiao Hai, Daxiang Liu,Liming Liu , Bingqin Zhao
Vegetation can enhance the stability of slopes by increasing the shear resistance of the soil. Shear stress applied to the soil matrix is resisted by the pullout strength of the roots via the friction at contact points between the soil and the roots. The effectiveness of root reinforcement depends on interface friction between soil and roots. In this study, tests were carried out on Indigofera amblyantha Craib roots, by measuring resistance as they are pulled out of the soil where the soil has varying dry densities. The results reveal three phases in the relationship between the pullout force and the slippage of the roots, i.e. (1) steep rise, (2) steep fall, and (3) gradual decline. In the first phase, the pullout force is increasing sharply and linearly up to a maximum when the slippage is about 10mm. With continued slippage, the required pullout force decreases significantly and nonlinearly in up and down fluctuations. Eventually, the pullout force reaches zero. For soil with a given dry density, the maximum pullout force increases linearly with increasing root diameter, and the correlation coefficient is greater than 0.9. Further, for a root with a given diameter, the maximum pullout force increases with increasing soil dry density. When the root breaks on pulling, it is called tensile failure; when the root is fully pulled out, it is called friction failure. The mode of failure for all roots is friction failure, for soil with dry densities of 1.35 g/cm3, 1.45 g/cm3, and 1.55 g/cm3. For soil with a dry density of 1.65 g/cm3, and root diameter under 0.716 mm, the observed failure mode is generally tensile; for diameters over 0.716 mm, the failure mode changes to friction; that is, thin roots break, thick roots get pulled out
Показать больше [+] Меньше [-]Influence of Government Subsidies for Green Technology Development on the Performance of Chinese New-Energy Automobile Enterprises Полный текст
2020
Hongjun Xiong and Yi Shen
Recently, facing situations of insufficient energy and harsh environmental conditions, new-energy vehicles begin to enter people’s lives. But considering many factors such as price and market acceptance development of new-energy automobile market must not lack government incentives. In recent two years, the government’s subsidy for green technology development to new-energy automobile enterprises has entered the post-subsidy era. To explore the sustainable development of new-energy automobile enterprises, Foton automobile was selected as the research object and the scale of government subsidy for green technology development to Foton automobile was clearly defined, the performance was analyzed by using multiple regression method. Results show that government subsidy and tax return for green technology development have a positive effect on Foton automobile’s performance, environmental regulation stringency has a significant positive moderating effect. Referring to the conclusions, some suggestions were put forward for Foton automobile’s future development and the development of newenergy automobile industry.
Показать больше [+] Меньше [-]Comparison of Lead Tolerance and Accumulation Characteristics of Fourteen Herbaceous Plants Полный текст
2020
Xiongfei Cai, Xinjie Yu, Li Lei, Bin Xuan, Ji Wang, Lingyun Zhang and Shijie Zhao
To compare lead (Pb) tolerance and accumulation characteristics, 14 herbaceous plants were treated with different concentrations of lead (0 mg?kg-1, 500 mg?kg-1, 1000 mg?kg-1, 1500 mg?kg-1, 2000 mg?kg-1) through an indoor pot experiment. Results indicated that the shoot dry weights (DWs), tolerance index (TI) and root tolerance index (RTI) of 14 herbaceous plants decreased with the increase of lead concentration. After comprehensive evaluation, Campsis grandiflora, Polygonum lapathifolium, Lolium perenne, and Poa annua were confirmed as tolerant plants to be cultivated in lead-zinc mining area. Moreover, shoots of the Rudbeckia hirta could effectively absorb the lead (I I) with the bioconcentration factor (BCF) of 2.29. The translocation factor (TF) of 6 herbaceous plants were larger than 1.0. They are: Polygonum lapathifolium (3.04) > Medicago sativa (2.49) > Rudbeckia hirta (1.72) > Talinum paniculatum (1.44) > Capsicum annuum cv. 276 (1.36) > Trifolium repens (1.21. Finally, after integration the BCF, TF and repair potential indices, we found that Rudbeckia hirta had a good restoration potential and its lead cumulation in the shoot was the highest (2.576 mg per plant) when the concentration was up to 1000 mg?kg-1. Therefore, Rudbeckia hirta could be identified as a pioneer species of Pbhyperaccumulator.
Показать больше [+] Меньше [-]The Effect of Ejectors on Reduction of Indoor Air Pollution in the Welding Room Полный текст
2020
Sattar Yunus, Makmur Saini, Rizal Sultan, Rusdi Nur and Ibrahim
In this study, the ejector installation has been designed and processed according to the plan and further investigated the effect of the ejector’s performance on reducing air pollutants in a welding chamber. This is done after gas and dust particles appear during the welding process. The measurement of air pollutants was carried out in two conditions. The first condition during the welding process was without using the ejector and the second condition is when the welding process continues and the ejector runs simultaneously. The measurements were made for carbon monoxide (CO) gas, nitrogen monoxide (NO) gas and total suspended particles. The ambient gas sampler was used in measuring CO and NO gases, while the Staflex air sampler measures dust particles. The results show that when the ejector is run or in the second condition, carbon monoxide and nitrogen monoxide and total dust particles are lower in concentration compared to the situation when the ejector is not running.
Показать больше [+] Меньше [-]Isolation and Characterization of Bacterial Isolates from Psidium guajava Obtained from Local Markets of Patna and Their Antibiotic Sensitivity Test Полный текст
2020
Deepak Kumar Jha, Ritu Raj, Pravritti, Samiksha, Aditi, Gulistan Parveen and Niti Yashvardhini
The study was conducted to investigate the presence of antibiotic resistant bacteria in guava, sold in the local markets of Patna. A total of twenty five fresh samples of guava were collected from five different market places in Patna city. Several microbiological tests were performed to assess the growth and type of bacteria. The colonies were isolated and identified as isolate 1 and 3 (identical to Staphylococcus spp.), isolate 2 (identical to Escherichia spp.) and isolate 4 and 5 (identical to Bacillus spp.) based on their cultural, morphological, Gram’s staining and biochemical characteristics. Antibiotic susceptibility tests were conducted to detect their actual resistance capability. In the present study, S1 and S3 were found resistant to ampicillin, chloramphenicol, ofloxacin and intermediate to gentamycin while S2 was found resistant to ampicillin, chloramphenicol, gentamycin, ciprofloxacin, cephalexin and intermediate to ofloxacin. The isolates S4 and S5 were found sensitive to gentamycin, intermediate to chloramphenicol and resistant to ciprofloxacin. Results of this study showed that the guava samples obtained from different markets of Patna possess multidrug resistant bacteria.
Показать больше [+] Меньше [-]Potency of Mancozeb Conjugated Silver Nanoparticles Synthesized from Goat, Cow and Buffalo Urine Against Colletotrichum gloeosporioides Causing Anthracnose Disease Полный текст
2020
S. N. Raghavendra, H. S. Raghu, C. Chaithra and A. N. Rajeshwara
Silver nanoparticles of 22-40 nm size were synthesized using goat, cow and buffalo urine. These nanoparticles are conjugated with a fungicide (Mancozeb). The antifungal activity of these conjugated nanoparticles (Mc-AgNPs) was tested against Colletotrichum gloeosporioides which causes anthracnose disease in various fruits and vegetables. This fungus infects during pre and post-harvesting seasons causing a significant decrease in the quantity and quality of the product. The fungicide conjugated AgNPs were characterized by UV-Visible, FTIR, SEM and XRD analysis. The synthesis of AgNPs was confirmed by the UV-visible spectroscopy. The shape of AgNPs was found to be spherical. The Mc-AgNPs from goat, cow and buffalo urine exhibited 146.15%, 133.33% and 114.28% more antifungal activity than the fungicides alone respectively. The results indicate that the Mc-AgNPs from goat urine showed more efficacy than cow and buffalo urine. The fungicide-conjugated AgNPs drastically reduce the amount of fungicide to be applied against Colletotrichum gloeosporioides, which in turn reduce the hazardous effect caused by fungicides. Further, these can be tested to control other pathogenic fungi also.
Показать больше [+] Меньше [-]Detoxification of Glucose, Ammonium and Formaldehyde Using Nitrification and Plant Processes Полный текст
2020
Denesya Natalia Paris and Sarwoko Mangkoedihardjo
The purpose of this study was to obtain the removal efficiency values from glucose, ammonium and formaldehyde based on toxicity units. The nitrification process is applied using nitrifying bacteria and the process of plants using water hyacinth. The toxicity tests used were bacterial respiration test and test with batch reactor system for plants. The results show that the EC50 value of formaldehyde was smaller than ammonium and glucose. Formaldehyde was the most toxic substance among these substances, but its detoxification efficiency was high; this may be due to an antagonistic effect (from toxic to less toxic) mixture of substances.
Показать больше [+] Меньше [-]Effective Removal of Cr(VI) from Aqueous Solution Using Modified Orange Peel Powder: Equilibrium and Kinetic Study Полный текст
2020
L. P. Liang, Q. Wang, F. F. Xi, W. S. Tan, Y. T. Zhang, L. B. Cheng, Q. Wu, Y. Y. Xue and X. Meng
A new adsorbent modified from orange peel (OP) was successfully synthesized by ethylenediamine crosslinking method to remove Cr(VI) from wastewater. The modified orange peel powder (MOPP) was investigated in a batch adsorption system, including both equilibrium adsorption isotherms and kinetics. Effects of several factors, including adsorbent dose, initial pH and Cr(VI) concentration were studied. The data indicated that the pH was not an essential factor that affected the adsorption process, it has a wide pH range from 4 to 10, and high adsorbent dose and lower Cr(VI) concentration could increase the Cr(VI) removal efficiency. Equilibrium data were analysed using the Langmuir, Freundlich and Temkin isotherm models and found to be well represented by the Langmuir isotherm model. The maximum capacity (qmax) obtained from Langmuir model was 52.08 mg/g at pH 6.0. The kinetics of adsorption followed the pseudo-second-order kinetic equation. The results suggest that MOPP is an inexpensive and efficient adsorbent for removing Cr(VI) from aqueous solution.
Показать больше [+] Меньше [-]Desulfurization of Fuel by [Bmim]CoCl3 and Potassium Monopersulfate Полный текст
2020
Jun Zhang, Hang Xu and Yang Li
Functional ionic liquid [Bmim]CoCl3 was prepared with potassium monopersulfate compound (PMS) to form extraction catalytic oxidative desulfurization system for benzothiophene (BT) removal. The best reaction conditions for removing BT were as follows: m (ionic liquid) = 2 g, m(PMS) = 1.5 g, C (initial sulphur) = 500 ppm, T = 40°C ~ 50°C. The desulfurization rate could be reached at 92.4 %. The ionic liquid still had higher activity after 5 cycles of reuse which exhibited that there was only a slight difference in the amount of the oxidant. It was proved that [Bmim]CoCl3 ionic liquid combined with oxidant PMS has an excellent desulfurization performance.
Показать больше [+] Меньше [-]Microclimate Energy Considerations in Building Design for Arid Regions Полный текст
2020
A. A. Alaskary, A. M. Hasson, M. J. Jweeg and M. L. Al-Waily
Climate is one of the main parameters that can influence building designs in Iraq. Analysis and assessment of microclimatological data can aid urban architects and engineers to optimize human comfort through environmentally sustainable practices. The results indicated that the long-term measurements of total solar insolation and ambient temperatures have increased by 2.9% and 6.5% respectively. Albedo resulted in good correlation with heating coefficients and temperature of R2 = 0.89 and 0.63 respectively. Annual cooling degree days and heating degree days have reduced, while annual mean ambient temperatures and annual solar radiation have increased.
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