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In this paper, the influence law was analyzed, the effective parameter range was determined. Based on the significance analysis of the orthogonal experiment with three factors and three levels, the order of the influence degree of each parameter on the forming quality of the end is obtained. According to the optimized simulation analysis in the effective scheme, the optimal forming process parameters were determined. The results show that the order of the influence of various factors on the diameter of the roll cut is as follows: roll cutting speed> friction factor> baffle gap; the best combination of process parameters is A2B1C1, the friction factor is 0,5, the roll cutting speed is 1/rad · s–1 and the baffle gap is 0,1/mm. [ABSTRACT FROM AUTHOR]

Particle-into-Liquid Samplers (PILS) have become a standard aerosol collection technique, and are widely used in both ground and aircraft measurements in conjunction with off-line ion chromatography (IC) measurements. Accurate and precise background samples are essential to account for gas-phase components not efficiently removed and any interference in the instrument lines, collection vials or off-line analysis procedures. For aircraft sampling with PILS, backgrounds are typically taken with in-line filters to remove particles prior to sample collection once or twice per flight with more numerous backgrounds taken on the ground. Here, we use data collected during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ) to demonstrate that not only are multiple background filter samples are essential to attain a representative background, but that the chemical background signals do not follow the Gaussian statistics typically assumed. Instead, the background signals for all chemical components analyzed from 137 background samples (taken from ∼78 total sampling hours over 18 flights) follow a log-normal distribution, meaning that the typical approaches of averaging background samples and/or assuming a Gaussian distribution cause an over-estimation of background samples – and thus an underestimation of sample concentrations. Our approach of deriving backgrounds from the peak of the log-normal distribution results in detection limits of 0.25, 0.32, 3.9, 0.17, 0.75 and 0.57 μg m −3 for sub-micron aerosol nitrate (NO 3 − ), nitrite (NO 2 − ), ammonium (NH 4 + ), sulfate (SO 4 2− ), potassium (K + ) and calcium (Ca 2+ ), respectively. The difference in backgrounds calculated from assuming a Gaussian distribution versus a log-normal distribution were most extreme for NH 4 + , resulting in a background that was 1.58× that determined from fitting a log-normal distribution. [ABSTRACT FROM AUTHOR]

The development of the approximate blank size should be done to determine the size of a blank to produce the shell to the required depth and to determine how many draws will be necessary to produce the shell. This is determined by the ratio of the blank size to the shell size. Various methods have been developed to determine the size of blanks for drawn shells. These methods are based on algebraic calculations; the use of graphical layouts; a combination of graphical layouts and mathematics. [ABSTRACT FROM AUTHOR]

Abstract: In the deep drawing of cups, the earing defect is caused by planar anisotropy in the sheet and friction between the blank and punch/die. In the past, several research efforts have been directed toward developing strategies for eliminating or mitigating the formation of ears. In this paper, we consider the concept of using drawbeads to minimize ear formation, thus overcoming the effects of anisotropy and friction. The study conducted and described here is entirely numerical. The object is to establish a numerical algorithm that will lead to an optimal drawbead contour that minimizes the earing defect in deep drawing. The algorithm is iterative in nature and involves performing simulations of the deep drawing process using finite element analysis, constructing an error metric at the end of each iteration, and utilizing the error metric to adjust the drawbead contour at the end of each iteration. The cycle is repeated until the error metric satisfies a preset convergence criterion. This iterative design process leads to an optimal drawbead contour. Several different test problems are considered, including the drawing of circular and square cups. Simulation results are very encouraging with reasonable number of iterations to arrive at the optimal drawbead contour. [Copyright &y& Elsevier]

Experimental investigations into the drawing of hemispherical cups were conducted with aluminium and copper blanks using the recently developed friction-actuated blank-holding technique. Blanks of different diameters and thicknesses were used in the experiments. Urethane pads of different hardnesses were also tested. Conditions for consistently producing wrinkle-free cups were established. To ascertain the quality of the cups produced, the variations of the thickness, the equivalent strain imposed on the metal, the hardness and the roughness along the cup wall were measured. Results from these investigations are presented in this paper. [Copyright &y& Elsevier]

Chinese dome digesters are usually operated at long hydraulic retention times (HRT) and low influent total solids (TS) concentration because of limited mixing. In this study, a newly optimised Chinese dome digester with a self-agitating mechanism was investigated at a pilot scale (digester volume = 500 L) and compared with a conventional Chinese dome digester (as blank) at 15% influent TS concentration at two retention times (30 and 40 days). The reactors were operated at ambient temperature: 27–33 °C. The average specific methane production, volatile fatty acids and percentage of volatile solids (VS) reduction are 0.16 ± 0.13 and 0.25 ± 0.05L CH4/g VS; 1 ± 0.5 and 0.7 ± 0.3 g/L; and 51 ± 14 and 57 ± 10% at 40 days HRT (day 52–136) for the blank and optimised digester, respectively. At 30 days HRT (day 137–309) the results are 0.19 ± 0.12 and 0.23 ± 0.04 L CH4/g VS; 1.2 ± 0.6 and 0.7 ± 0.3 g/L; and 51 ± 9 and 58 ± 11.6%. Overall, the optimised digester produced 40% more methane than the blank, despite the high loading rates applied. The optimised digester showed superior digestion treatment efficiency and was more stable in terms of VFA concentration than the blank digester, can be therefore operated at high influent TS (15%) concentration. [ABSTRACT FROM AUTHOR]