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31.
A mixed microbial culture degraded a mixture of benzoate (863 mg/L), 3-chlorobenzoate (3-CB) (69.7 mg/L), and pyruvate (244 mg/L) under denitrifying conditions in a chemostat. Biodegradation under denitrifying conditions was stable, complete (effluent concentrations below detection limits), and proceeded without the production of toxic intermediates like chlorocatechols. The addition of oxygen at mass input rates of 6.2%, 15.5%, and 43.9% of the mass input rate of chemical oxygen demand (COD) (337 mg COD/h) did not induce the synthesis of aerobic biodegradation pathways and thus did not disrupt biodegradation. Rather, the oxygen was used as a terminal electron acceptor, displacing a stoichiometric amount of nitrate, leading to microaerobic conditions (dissolved oxygen concentration <0.050 mg/L) in which oxygen utilization and denitrification occurred simultaneously. The reduction of nitrate occurred fully to N2 gas with no accumulation of nitrite, nitrous oxide, or nitric oxide, although the ability of the culture to transfer electrons to the nitrogen oxides decreased as the oxygen input was increased. The anoxic benzoate uptake capability was unaffected by the increase in oxygen addition, but the anoxic 3-CB uptake capability increased, as did the level of benzoyl-CoA reductase in the cells. 相似文献
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33.
H. Kursat Celik Hasan Yilmaz Allan E. W. Rennie Recep Cinar M. Ziya Firat 《Journal of Failure Analysis and Prevention》2018,18(5):1099-1110
This paper focuses on a design analysis of a flat die used in an agricultural biomass pelletizing machine by considering its high-pressure loading failure susceptibility. The pellet die is one of the key elements in a pelletizing machine, and the strength of the die plate has an important role on the pellet’s quality and producibility. In fact, higher compression ratio (CR—the ratio of effective length and the internal (press channel) diameter of a die orifice/hole) will provide denser pellets which is a desired phenomenon, however, if the compression pressure is too high or CR is not determined to compensate high pressures, the raw material may block the die and the die may experience deformation failure due to overloading. If the desire is to make high-quality pellets with no die failure, optimum flat die hole/orifice design parameters should be used which can provide the best CR for a specific compression pressure. This is the core motivation of this research. In this study, finite element analysis (FEA)-based design exploration has been utilized for a sample single hole flat die with various die geometry parameters against various compression pressure values. Following the FEA design exploration undertaken, a response surface analysis (RSA) was carried out and then estimation models (empirical equations), which could be used to calculate parameters of the die hole/orifice against applied compression pressure and failure susceptibility based on structural stress and deformation, was described. The results gained from the RSA have indicated that the estimation models have high R2 values (higher than 98%) which could be used for adequately predicting failure susceptibility indicators. In addition to this, FEM-based simulation printouts have provided useful stress distribution visuals on the die against different compression pressure values. Most especially, the study has highlighted that a detailed structural optimization study may be scheduled in order to obtain die geometry design parameters with a focus on the failure susceptibility. 相似文献
34.
Emine Billur Sevinis Canan Sahin Mehmet Emin Cinar Mehmet Sayip Eroglu Turan Ozturk 《Polymer Engineering and Science》2016,56(12):1390-1398
In this work, copolymers of dithienothiophenes (DTT) and DTT‐4,4‐dioxide (DTT‐S,S‐O2) with mesitylboron were prepared for optoelectronic applications. Optical and electrochemical investigations were performed giving rise to the band gaps of 2.46–3.21 and 2.18–2.88 eV, respectively. Copolymers possessing DTT‐S,S‐O2 units demonstrated the lower band gaps. Density functional theory investigations of the model compounds revealed the presence of an intramolecular charge transfer transition between the donor DTT units and the boron acceptor atoms. POLYM. ENG. SCI., 56:1390–1398, 2016. © 2016 Society of Plastics Engineers 相似文献
35.
Bulent Icgen Salih Batuhan Salik Lale Goksu Huseyin Ulusoy Fadime Yilmaz 《Journal of surfactants and detergents》2016,19(3):637-644
Due to natural attenuation, anionic detergents in surface waters are not inferred as big environmental issues. However, the effluents from large industrial areas with high detergent concentrations can have significant local impacts. These circumstances can be diminished by using efficient detergent‐degrading bacterial isolates through bioaugmentation. In this study, detergent plant effluents were analysed by using a methylene blue active substance assay to determine detergent content during natural attenuation processes, and after single augmentations of 12 anionic detergent‐degrading bacterial isolates with high detergent tolerating abilities in batch microcosms. Maximum bioattenuation of detergents was determined as 56 % after 66 h incubation under the conditions that mimicked the natural environment. Bioattenuation was enhanced as much as 83 and 91 % in 78 h incubation time through single microbial augmentations of filter‐sterilized and non‐sterilized effluents, respectively. Eight Pseudomonas and one Aeromonas species were found to be highly competitive by showing high biodegradation abilities in pure culture experiments as well as enhancing degradation of detergents in both filter‐sterilized and non‐sterilized effluents through their single augmentations. Although remaining three isolates, namely Pseudomonas fluorescens SDS6, P. resinovorans SDS10‐2, and P. corrugata SDS10‐3 displayed lower degrading abilities in pure culture experiments than the natural attenuation, they later turned out to be actively enhancing the degradation of detergents during their single augmentations. 相似文献
36.
Gréta Gergely Filiz Cinar Sahin Gültekin Göller Onuralp Yücel Csaba Balázsi 《Journal of the European Ceramic Society》2013,33(12):2313-2319
Nano hydroxyapatite (nHA)–zirconia (ZrO2) composites have been produced by spark plasma sintering (SPS). During the SPS process low temperatures (600–950 °C) and short dwelling time (5 min) have been applied to avoid the decomposition of nHA as well as the reaction between nHA and ZrO2. The grain size of the sintered composites was between 200 and 1000 nm. Carbon diffusion was induced from the graphite die and layered composite structure was formed. These observations might be related to the spark plasma sintering side effects. The microstructure and mechanical properties of high hydroxyapatite content zirconia composites have been found to be influenced and strongly correlated with the specialties of SPS method. 相似文献
37.
The microwave‐assisted polycondensation of maleic anhydride and 1,6‐hexanediol was carried out using p‐toluenesulfonic acid as catalyst. The resulting unsaturated polyester was characterized using Fourier transform infrared (FTIR) and 1H NMR spectroscopy, and the molecular weight determined using gel permeation chromatography. 4,4′‐Decanediyldioxydi(N‐methyl‐p‐phenylenenitrone) was chosen as a model compound for the crosslinking of the unsaturated polyester. The crosslinking, which is known to proceed via 1,3‐dipolaric cycloaddition, was followed using differential scanning calorimetry. Additionally, the kinetics of the cycloaddition was evaluated at 120 °C using FTIR spectroscopy. Copyright © 2012 Society of Chemical Industry 相似文献
38.
39.
In the present study, silver nanoparticles were produced by hydrazine hydrate and oleylamine/oleic acid systems in order to investigate the effects of reducing agents with different strengths on the reduction mechanism. Particle size and size distribution of silver particles produced by slow reducing system were studied in detail by using transmission electron microscopy (TEM), X-Ray Diffraction (XRD), photon correlation spectroscopy (PCS), and surface plasmon resonance spectroscopy (SPR). Finally, reduction mechanism by oleylamine and oleic acid system was clarified and particles with average diameter of 2.7 nm were produced. Nano-sized particles were then placed at the center of the polymer fibers by coaxial electrospinning and nanocable like structures were produced. SEM and TEM were used for the characterization of these cables. 相似文献
40.
Cs. Balázsi F. Gillemot M. Horváth F. Wéber K. Balázsi F. Cinar Sahin Y. Onüralp Á. Horváth 《Journal of Materials Science》2011,46(13):4598-4605
Although capability of steels has been improved in the past by thermomechanical treatment, utilization of powder metallurgy
provides more controlled microstructure, a homogeneous dispersion of nanosized oxide particles in the metal matrix and tailored
properties in terms of strength and radiation resistance. This article is summarizing recent results on preparation, structural,
and mechanical investigation of oxide dispersed strengthened steel (ODS). Two commercial steel powders, austenitic 17Cr12Ni2.5Mo2.3Si0.1C
and martensitic Fe16Cr2Ni0.2C powders have been used as starting materials. Nanosized yttria dispersed martensitic and austenitic
sintered steel samples have been realized by powder metallurgical methods. An efficient dispersion of nano-oxides in ODS steels
was achieved by employing high efficient attrition milling. A combined wet and dry milling process of fine ceramic and steel
particles is proposed. Spark Plasma Sintering (SPS) was applied to realize nanostructured steel compacts. Grains with 100 nm
mean size have been observed by SEM in sintered austenitic ODS. In comparison, the sintered martensitic dry milled and martensitic
dry and combined milled ODS microstructure consisted of grain size with 100–300 nm in each case. A brittle behavior is shown
in all of the cases. The martensitic ODS is two times harder than the austenitic ODS. The bending strength high as 1806.7 MPa
was found for the martensitic ODS, whereas 1210.8 MPa was determined for the austenitic ODS. The combined milling assured
higher strength and hardness compared to dry milling. 相似文献