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排序方式: 共有124条查询结果,搜索用时 15 毫秒
1.
ABSTRACT Treatments of phenol formaldehyde producing wastewater (PFPW) by electrooxidation (EO) and electro-Fenton (EF) successive processes were carried out in a batch electrolytic reactor using graphite (Gr) and stainless steel (Ss) electrodes. After the completion of the EO process, the wastewater was further treated with EF process. The influence of operating variables such as current density, operating time, initial pHi and H2O2 concentration was evaluated for removals of phenol, TOC and COD in PFPW. Gr/Gr, Gr/Ss or Ss/Ss and Ss/Gr electrode pair were used as anode and cathode. The best removal efficiency in the EO process was obtained with Gr/Gr (93%) as compared to Gr/Ss (82%), Ss/Ss (63%) and Ss/Gr (55%). The removal efficiencies for the EO process using Gr-Gr electrode pair were obtained as 93% for phenol, 61% for COD and 44% for TOC at initial pHi 7,5 g/L of NaCl, 50 mA/cm2 and 5 h. In the EF process, the removal efficiencies at pHi 3,5 mA/cm2 and 30 mM H2O2 and 45 min were 100% for phenol, 76% for COD and 59% for TOC. This study provided that the successive processes are an effective method for the removal of phenolic compounds from the wastewater. 相似文献
2.
Kenan Bulcar Mustafa Akyol Gönül Akça Ali Osman Ayaş Mustafa Topaksu Ahmet Ekicibil 《Journal of Superconductivity and Novel Magnetism》2014,27(11):2631-2637
We have worked on the structural and magnetic properties of Zn0.99?xMn0.01Gd x O δ (for x = 0.02, 0.03, and 0.04) compounds prepared by using a sol–gel method. The x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy were used to understand the structural properties of the samples. We observed that co-substitution of Mn (1 %) and Gd (2–4 %) into the ZnO does not change the hexagonal structure. Scanning electron microscope (SEM) images show us that the grain size decreases with the increasing amount of the Gd into the ZnO matrix. The magnetic properties of the samples have been investigated by using magnetic hysteresis and DC susceptibility measurements. The ZMG1 sample shows a weak ferromagnetic behavior at room temperature, whereas the ZMG2 and ZMG3 samples exhibit a paramagnetic nature. Furthermore, it is also found that the magnetizations of the samples decrease with increasing Gd content in the ZnMnO system due to the enhancing interaction between Gd 3+ ions. We summarize that the co-substitution of Mn and Gd into the ZnO generates a room-temperature ferromagnetism, but it still needs more work to obtain strong and high coercivity magnetic loops for applications. 相似文献
3.
Efficiency of Gold Nano Particles on the Autoxidized Soybean Oil Polymer: Fractionation and Structural Analysis
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Polyunsaturated plant oils have gained great interest as monomers to produce biodegradable polymers obtained from renewable resources due to the limited existing sources of petroleum oil and environmental issues. Soybean oil was autoxidized by exposure to atomospheric oxygen at room temperature with or without the presence of gold nanoparticles (Au NPs) 5–41 days. When the autoxidation process was catalyzed with Au NPs, the molecular weight of the oxidized oil was increased in 5 days. In contrast to this, without Au NPs, the oxidized oil was still a fluidized liquid. Autoxidized soybean oil polymer in toluene solution with gold NP showed a surface plasmon resonance at λmax = 540 nm in a UV–VIS spectrometer and a fluorescence emission spectrum at λmax = 450 nm, when it was irradiated at λmax = 390 nm. The higher molecular weight of the polymeric oils was successively fractionated by the extraction from the solvent‐non‐solvent mixture CHCl3/petroleum ether with the volume ratio of 5:15. Three polymeric oils fractions with different molecular weight (ca 1000, 4000, and 40,000 g/mol) were obtained. GC–MS analysis, 1H‐NMR and GPC techniques were used in the structural analysis of the fractionated polymeric oils. 相似文献
4.
Ass. Prof. Dr. Gulsun ?zyurt Ali Serhat ?zk��t��k Abdurrahman Polat 《Journal für Verbraucherschutz und Lebensmittelsicherheit》2011,6(2):167-174
The effects of rosemary extract addition on oxidative stability of cooked sea bream during frozen storage period were investigated. Sea bream fillets were fried, oven baked and grilled. Three groups with rosemary extract were also cooked by the same methods and cooked samples (with and without rosemary extract) were stored in ?18?°C for 4?months. After cooking procedures, the FFA formation was quite similar in fresh-raw and fried sea bream fillets, but significantly increased oven baked (0.31?C0.33% oleic acid) and grilled fillets (0.39?C0.40% oleic acid). The highest value of PV was also obtained from grilled fillets (1.18?C1.58?meq/kg). However, TBA values (1.92?mg MA/kg for fresh-raw fillet) did not increase in sea bream fillets after the frying and grilling procedure except oven baking without rosemary extract (2.41?mg MA/kg). A considerable increase in the FFA, PV and TBA was observed in all cooked groups during frozen storage period. The treated samples with rosemary extract generally showed slower PV and TBA formation than those of the untreated samples. However, the additions of rosemary extract have positive effect on sensory quality of baked sea bream. 相似文献
5.
6.
Derya Eren Akyol G. Mirac Bayhan 《The International Journal of Advanced Manufacturing Technology》2008,37(5-6):576-588
This paper addresses the problem of scheduling a set of independent jobs with sequence-dependent setups and distinct due dates
on non-uniform multi-machines to minimize the total weighted earliness and tardiness, and explores the use of artificial neural
networks as a valid alternative to the traditional scheduling approaches. The objective is to propose a dynamical gradient
neural network, which employs a penalty function approach with time varying coefficients for the solution of the problem which
is known to be NP-hard. After the appropriate energy function was constructed, the dynamics are defined by steepest gradient
descent on the energy function. The proposed neural network system is composed of two maximum neural networks, three piecewise
linear and one log-sigmoid network all of which interact with each other. The motivation for using maximum networks is to
reduce the network complexity and to obtain a simplified energy function. To overcome the tradeoff problem encountered in
using the penalty function approach, a time varying penalty coefficient methodology is proposed to be used during simulation
experiments. Simulation results of the proposed approach on a scheduling problem indicate that the proposed coupled network
yields an optimal solution which makes it attractive for applications of larger sized problems. 相似文献
7.
8.
Abdurrahman Karabulut Engin Gedik Ali Keçebaş Mehmet Ali Alkan 《Renewable Energy》2011,36(4):1293-1297
In the present study, to discover how teaching of renewable energy sources in Turkey is carried out at the university level, a questionnaire was developed and applied at different universities in Turkey. The analyses conducted on the data obtained from the questionnaire revealed that education about geothermal, solar and wind energy is given at master’s level, other renewable energy sources are taught at the undergraduate level within the curriculum of some engineering courses. The teaching performed about renewable energy sources is in Turkish and at encyclopedic level. As preparing and obtaining the required materials are costly, some problems are encountered in the teaching of renewable sources. In Turkish universities, no degree about renewable energy sources is granted. Hence, the country must make use of the people having engineering degree to capitalize on its renewable energy sources. As there is no program specializing on providing training about the renewable energy sources, it seems to be difficult to find experts about this issue. The current state of renewable energy sources education seems to be inadequate and it should be expanded and strengthened. 相似文献
9.
A Survey of Handover Techniques for Wireless ATM Networks 总被引:1,自引:0,他引:1
This paper provides a review and comprehensivecomparison of existing handover schemes proposed forwireless ATM networks. Existing schemes include thoseproposed by NEC, Olivetti, Bell Labs, Cambridge, Stanford, CMU, Berkeley, Michigan, VTT, andColumbia. We highlight the methodologies employed by thevarious schemes and reveal their differences. We discussissues related to the effect of ATM switch architectures on mobility implementation and on futurehandover paradigms. 相似文献
10.
Bahadir K Krbaht Bekir Salih Abdurrahman Tanyola 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(1):70-76
The electrochemical conversion of highly concentrated synthetic phenolic wastewater was studied on carbon electrodes in a batch electrochemical reactor. The effects of reaction temperature, electrolyte concentration, current density and initial phenol concentration on phenol conversion were elucidated. The wastewater was synthetically prepared and used in reactions carried out generally at 25 °C with an initial phenol concentration of 3500 mg dm?3. Although current density increased, phenol conversion% and initial phenol conversion rate did not increase correspondingly above 35 °C and an electrolyte concentration of 90 g dm?3. As the voltage values applied were increased, the increasing current density resulted in fast phenol conversion. Kinetic investigations denoted that overall phenol destruction kinetics was of zero order with an activation energy of 10.9 kJ mol?1. Under appropriate conditions, phenol was completely converted within 15 min for an initial phenol concentration of 98 mg dm?3 while 8 h was required to gain 95% conversion using 4698 mg dm?3. Solid polymeric materials were produced at initial phenol concentrations above 500 mg dm?3 using the appropriate current density. In the reaction medium, only mono‐, di‐ and tri‐substituted chlorophenols were formed and 100% of all species were either oxidised or contributed to the formation of a polymeric structure. Almost all of the phenol loaded to the reactor was converted into non‐passivating polymeric products, denoting a safe and easy method for the separation of phenol. © 2001 Society of Chemical Industry 相似文献