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Mustafa Evren Ersahin Recep Kaan Dereli Hale Ozgun Berivan Gunes Donmez Ismail Koyuncu Mahmut Altinbas Izzet Ozturk 《洁净——土壤、空气、水》2011,39(6):543-548
Baker's yeast industry has significant effects on environment due to significant water consumption and high strength wastewater production. Effluents from baker's yeast industry are characterized by high concentrations of biological oxygen demand (BOD5), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), total dissolved solids (TDS), sulfate, and dark brown color. The aim of this study is to provide a detailed quantitative and qualitative identification and characterization of the wastewater sources from different processes of a baker's yeast industry. It is identified that the most polluted wastewater components of the facility are coming from rotary drum filter and evaporation process. However, the highest pollution loads is identified as tank and equipment cleaning effluent due to very high flow rate from this source. The efforts should be on the way to minimize the water usage for the tank and equipment cleaning process, and to recycle less polluted waste streams back to the process. 相似文献
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In this paper, an experimental study on the cut depth, which is an important cutting performance indicator in the abrasive waterjet (AWJ) cutting of rock, was presented. Taguchi experimental design of an orthogonal array was employed to conduct the experiments. A variety of nine types of granitic rocks were used in the cutting experiments. The experimental data were used to assess the influence of AWJ operating variables on the cut depth. Using regression analysis, models for prediction of the cut depth from the operating variables and rock properties in AWJ machining of granitic rocks were then developed and verified. The results indicated that the cut depths decreased with increasing traverse speed and decreasing abrasive size. On the other hand, increase of the abrasive mass flow rate and water pressure led to increases in the cut depths. Additionally, it was observed that the standoff distance had no discernible effects on the cut depths. Furthermore, from the statistical analysis, it was found that the predictive models developed for the rock types had potential for practical applications. Verification of the models for using them as a practical guideline revealed a high applicability of the models within the experimental range used. 相似文献
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This paper presents an experimental study on the sawing of granitic rocks by circular diamond sawblades. The influence of the operating variables and rock properties on the specific energy were initially investigated and analyzed. To determine the most significant operating variables and rock properties influencing the specific energy, statistical analyses were then employed and the models were built for the estimation of specific energy depending on the operating variables and the rock properties. Moreover, the derived models were validated through statistical tests such as the determination coefficient, t-test, F-test, and residuals. The results indicated that the specific energy decreased with the decreasing of peripheral speed and the increasing of traverse speed, cutting depth, and flow rate of cooling fluid, respectively. It was concluded that, rather than the physico-mechanical properties, the mineralogical properties were the dominant rock properties affecting the specific energy. Additionally, the peripheral speed was statistically determined as the most significant operating variable affecting the specific energy. The peripheral speed was followed by the cutting depth, traverse speed, and flow rate of cooling fluid with respect to their level of significance on the specific energy. Furthermore, the model results revealed that the developed models have high potentials as a guidance for practical applications. 相似文献
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Wear Performance of Saw Blades in Processing of Granitic Rocks and Development of Models for Wear Estimation 总被引：1，自引：0，他引：1
This study investigates the wear performance of diamond circular saw blades in cutting of granitic rocks. An alternative wear measuring method is developed to measure the reduced blade radius without taking the blade off the machine. The effect on and contribution to the specific wear rate (SWR) of each operating variable are determined, and the SWR is correlated with rock properties. Morphologies of wearing surfaces of segments and rocks are also evaluated using scanning electron microscopy (SEM). Depending on both operating variables and rock properties, prediction models are developed for estimation of the SWR. Results show that the SWR increases with an increase in the peripheral speed and the traverse speed, while it decreases with an increase in the cutting depth and the flow rate of the cooling fluid. The peripheral speed, and the microhardness and proportions of minerals such as quartz, plagioclase, and feldspar are statistically determined as the significant variables affecting the SWR. Finally, it is disclosed that models developed for estimation of SWR have great potential for practical applications. 相似文献
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Collapse of zooplankton stocks during Liriope tetraphylla (Hydromedusa) blooms and dense mucilaginous aggregations in a thermohaline stratified basin 
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下载免费PDF全文 Izzet Noyan Yilmaz 《Marine Ecology》2015,36(3):595-610
A growing number of studies report an increase in jellyfish populations worldwide that may have consequences for marine planktonic food web dynamics. The principal objective of this study was to understand the changes in a zooplankton community during blooms of Liriope tetraphylla and subsequent mucilage events in the Sea of Marmara, a small highly stratified transitional basin between the Black and Aegean Seas. Liriope blooms observed in 2006 and 2007 reached a maximum abundance of 2978 ind.·m?3, following the species' first observation in 2005. Jellyfish species are known to play a key guild role by restructuring plankton communities and in the Sea of Marmara Liriope caused a temporal regime shift from a crustacean‐ to a jellyfish‐controlled system. A rapid decline in abundance of most important zooplankton species followed the Liriope increase, together with a drastic shift in community structure. The dominant summer–autumn species Penilia avirostris (Cladocera) vanished in the autumn of 2006 and was diminished ~30‐fold in 2007 when compared with years without Liriope. The decline in zooplankton and the devastating effects of mucilage on pelagic ecosystem and socio‐economics through restricting commercial fisheries implied sensitivity of the already perturbed Marmara ecosystem to changes in predator densities and environmental stability. 相似文献
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Buckling behavior of cross-ply cylinders under hydrostatic pressure is investigated using a semi-analytical finite element based on a consistent first order shear deformable shell theory. Potential loss due to external pressure, also called pressure stiffness (PS) is taken into account by making use of Koiter's related energy expression. A number of verification problems are solved and the numerical results are compared with the analytical results available in the literature and excellent agreement is observed. New numerical results are presented to assess the effect of PS on buckling due to hydrostatic pressure. It is shown that PS causes a decrease in the buckling load and this decrease depends on the size of the cylinder and the material. Also, issues related to thickness optimization are examined and optimal lamina thicknesses are determined for a number of cases with and without PS taken into account. 相似文献
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This paper presents an experimental and statistical study on the kerf width, used instead of the width of the cut in abrasive waterjet (AWJ) cutting. Pre-dimensioned granitic rocks were sampled for the experimentations designed by using Taguchi orthogonal arrays. The effects of the AWJ operating variables on the kerf width were studied and the rock properties were correlated with the kerf widths. Additionally, predictive models for the kerf widths were developed using multi-variable regression analysis and the developed models were verified through some statistical tests. The results demonstrated that the standoff distance and the traverse speed have significant effects on the kerf widths. The results also showed that water absorption, unit weight, microhardness, the maximum grain size of rock-forming minerals, and mean grain size of the rock have significant correlations with the kerf widths of the tested rocks. Furthermore, the modeling results revealed that the predictive models derived from rock properties, can be successfully used as a practical guideline. 相似文献
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We study quasinormal modes (QNMs) of uncharged Grumiller black hole (GBH). This massive BH has a Rindler acceleration a, and hence it is also called Rindler modified Schwarzschild BH. After reducing the radial equation of the massless Klein-Gordon equation to the Zerilli equation, we compute the complex frequencies of the QNMs of the GBH. To this end, an approximation method which considers small perturbations around its horizon is used. Considering the highly damped QNMs in the process proposed by Maggiore, the quantum entropy and area spectra of these BHs are found. Although the QNM frequencies are tuned by the Rindler term, we show in detail that the spacing does not depend on it. Here, the dimensionless constant ? of the area spectrum is found to be double of its Schwarzschild value. The latter result is also discussed. 相似文献
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Glucose‐fed high‐rate UASB reactors were tested at three COD/SO4 ratios and hydraulic retention times to promote sulfate reducing activity and observe the effects on reactor performance. Different COD/SO4 ratios (20, 10, and 5) resulted in changes in organic matter removal, methane production, alkalinity, dissolved sulfide and biomass concentrations and profile. The COD removal dropped from 95 to 80–84 % at the lowest COD/SO4 ratio. Sulfate was removed at 79 to 89 % at the highest ratio and dropped to 72 to 74 % with increasing sulfate loading. Alkalinity was produced at higher levels with increasing sulfate loading. Specific methane production dropped with decreasing hydraulic retention times. Sulfate‐reducing activity used a maximum of 11.7 % of organic matter at the highest sulfate loading level, producing a slight shift to sulfate‐reducing activity in the substrate competition between sulfate‐reducing bacteria and methanogens. Increased sulfate loading at COD/SO4 ratios of 10 and 5 caused deterioration of the concentration profile of the sludge, resulting in biomass washout and decreased volatile fraction of biosolids in the reactors. 相似文献