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191.
Surface roughness has an important role in the performance of finished components. End ball milling is used for achieving high surface quality, especially in complex geometries. Depending on the cutting conditions selected for ball end milling, different milling strategies can be applied. The produced surface quality is greatly affected from the selected milling strategy. The present paper examines the influence of the milling strategy selection on the surface roughness of an Al7075-T6 alloy. A number of cutting parameters are tested (axial and radial depth of cut, feed rate, inclination angles φ and ω) in order to perform 96 experiments and their results are processed using regression analysis and analysis of variance. All possible milling strategies are considered (vertical, push, pull, oblique, oblique push and oblique pull) and for each one of them, a mathematical model of the surface roughness is established, considering both the down and up milling. All models are statistically validated and experimentally verified, and can be used within the limits of the investigating cutting conditions. The polynomials produced are of the third order and the statistically most significant parameters are presented. 相似文献
192.
Improvement of COD and color removal from UASB treated poultry manure wastewater using Fenton's oxidation 总被引:1,自引:0,他引:1
The applicability of Fenton's oxidation as an advanced treatment for chemical oxygen demand (COD) and color removal from anaerobically treated poultry manure wastewater was investigated. The raw poultry manure wastewater, having a pH of 7.30 (+/-0.2) and a total COD of 12,100 (+/-910) mg/L was first treated in a 15.7 L of pilot-scale up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated for 72 days at mesophilic conditions (32+/-2 degrees C) in a temperature-controlled environment with three different hydraulic retention times (HRT) of 15.7, 12 and 8.0 days, and with organic loading rates (OLR) between 0.650 and 1.783 kg COD/(m3day). Under 8.0 days of HRT, the UASB process showed a remarkable performance on total COD removal with a treatment efficiency of 90.7% at the day of 63. The anaerobically treated poultry manure wastewater was further treated by Fenton's oxidation process using Fe2+ and H2O2 solutions. Batch tests were conducted on the UASB effluent samples to determine the optimum operating conditions including initial pH, effects of H2O2 and Fe2+ dosages, and the ratio of H2O2/Fe2+. Preliminary tests conducted with the dosages of 100 mg Fe2+/L and 200 mg H2O2/L showed that optimal initial pH was 3.0 for both COD and color removal from the UASB effluent. On the basis of preliminary test results, effects of increasing dosages of Fe2+ and H2O2 were investigated. Under the condition of 400 mg Fe2+/L and 200 mg H2O2/L, removal efficiencies of residual COD and color were 88.7% and 80.9%, respectively. Under the subsequent condition of 100 mg Fe2+/L and 1200 mg H2O2/L, 95% of residual COD and 95.7% of residual color were removed from the UASB effluent. Results of this experimental study obviously indicated that nearly 99.3% of COD of raw poultry manure wastewater could be effectively removed by a UASB process followed by Fenton's oxidation technology used as a post-treatment unit. 相似文献
193.
Bulent Aktas Suleyman Tekeli Serdar Salman 《Journal of Materials Engineering and Performance》2014,23(1):294-301
In this study, 8 mol% yttria-stabilized cubic zirconia (8YSZ) powder as a matrix material and 0-15 wt.% La2O3 powder as an additive were used to determine the effect of La2O3 addition and its amount on the phase stability, microstructure, sintering, and mechanical properties of 8YSZ. Colloidal processing was used to mix the powders uniformly and to obtain a homogenous microstructure. XRD results showed the existence of only a cubic crystal structure for 1 and 5 wt.% La2O3 addition amounts. However, La2Zr2O7 with a hexagonal and cubic crystal structure was observed in 8YSZ specimens doped with 10 and 15 wt.% La2O3. Further, up to 5 wt.% La2O3 was completely dissolved in the crystal structure of the specimens; however, above 5 wt.%, La2O3 reacted with 8YSZ at high temperatures and formed pyrochloric La2Zr2O7. Grain size measurements revealed that the grain size of 8YSZ increased up to 1 wt.% La2O3 addition, and then decreased beyond this amount. The hardness and fracture toughness of 8YSZ decreased and increased, respectively, with the increasing La2O3 amount. 相似文献
194.
Ayla Kaya Betul Demirci Suleyman Doğu Muhittin Dinç 《International Journal of Food Properties》2017,20(11):2639-2644
The genus Stachys L. one of the largest genera of Lamiaceae and Stachys species are used by many people for the therapeutic value of their essential oils. In this study, water-distilled essential oil of three species of Stachys was analysed. The analysis was performed by using gas chromatography-flame ionisation detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) systems simultaneously. The major components found were hexadecanoic acid (23.7%), dodecanoic acid (11.3%), and caryophyllene oxide (10.7%) for S. sericantha P.H. Davis (endemic); α-pinene (53%), β-pinene (8.2%) for S. gaziantepensis M. Dinc and S. Do?u (endemic); Menthyl acetate (15.3%), isomenthone (15.0%), pulegone (10%), spathulenol (7.0%), and caryophyllene oxide (6.7%) for S. mardinensis (Post) R. Mill. 相似文献