In this paper, a practical Multidisciplinary Design Optimization (MDO) system for an aircraft design is developed. The MDO system is based on the integration of computational fluid dynamics (CFD) codes and the NASTRAN based aeroelastic-structural interface code. Kriging model is employed to save the computational time of objective function evaluation in Multi-Objective Genetic Algorithm (MOGA). As a result of optimization, several nondominated solutions, indicating the trade-off among the drag, the structural weight, the drag divergence and the pitching moment, have been found.
In this paper, we describe a multidisciplinary design exploration technique with a high-fidelity analysis applied to the winglet design for a commercial jet aircraft. The minimization of the block fuel at a fixed aircraft operating range and a maximum takeoff weight were selected as design objectives. Both objective functions were estimated from a computational fluid dynamics based aerodynamic drag and a finite element method based structural weight. Various computational fluid dynamics and optimization techniques, such as the midfield drag decomposition method, the automatic computational fluid dynamics mesh generation, the kriging surrogate model, and multi-objective genetic algorithms, were integrated and applied to the detail design exploration. Computational fluid dynamics with the midfield drag decomposition method showed the effect on wave, induced, and profile drag components due to different winglet defining parameters. Practical design decision was explored based on the Pareto front and some design criteria that were uncovered within the numerical optimization. Finally, the design process was validated through the validation of the kriging approximation and aerodynamic characteristics based on the wind-tunnel test. Nomenclaturechord length of wing C wr = root chord length of winglet C wt = tip chord length of winglet F ind = induced drag seed vector F s;H = entropy & enthalpy drag seed vector k w = form factor of winglet l w = span length of winglet M = Mach number n = unit normal vector to a surface P = pressure R = gas constant Re c = Reynolds number based on mean aerodynamic chord S ref = reference wing area S wet = wetted area t=c = winglet thickness divided by local chord length u = velocity vector V = control volume W = structural weight WA = Trefftz plane = specific heat ratio s = entropy variation H = enthalpy variation w25 = winglet sweep angle at 25% chord length l = laminar viscosity coefficient t = turbulent viscosity coefficient = density Subscript 1 = freestream value
[1] The flowing fluid electric conductivity (FFEC) logging method is an efficient way to provide information on the depths, salinities, and inflow strengths of individual conductive features intercepted by a borehole, without the use of specialized probes. Using it in a multiple-flow rate mode allows, in addition, an estimate of the transmissivities and inherent (far-field) hydraulic heads in each of the conductive features. The multirate method was successfully applied to a 500-m borehole in a granitic formation and reported recently. The present paper describes the application of the method to two zones within a 1000-m borehole in sedimentary rock, which produced, for each zone, three sets of logs at different pumping rates, each set measured over a period of about 1 day. The data sets involve several complications, such as variable well diameter, gradual water level decline in the well during logging, possible fluid flow through the unfractured rock matrix, and effects of drilling mud.Various techniques were applied to analyze the FFEC logs: direct-fitting, mass integral, and the multirate method mentioned above. In spite of complications associated with the tests, analysis was able to identify 44 hydraulically conducting fractures distributed over the depth interval 150-775 m below ground surface. The salinities (in FEC), and transmissivities and hydraulic heads (in dimensionless form) of these 44 features were obtained and found to vary significantly among one another. These results were compared with transmissivity and head values inferred from eight packer tests that were conducted in this borehole over the same depth interval. FFEC results were found to be consistent with packer test results, thus demonstrating the robustness of the FFEC logging method under nonideal conditions. Citation: Doughty, C., C.-F. Tsang, K. Hatanaka, S. Yabuuchi, and H. Kurikami (2008), Application of direct-fitting, mass integral, and multirate methods to analysis of flowing fluid electric conductivity logs from Horonobe, Japan, Water Resour. Res., 44, W08403,
NIR WGM resonators are fabricated from energy-donating and accepting conjugated polymers.
In rice (Oryza sativa L.), seeds exposed to heat stress during grain filling exhibit delayed germination because of DNA methylation levels at promoters of abscisic acid (ABA, a germination-inhibiting hormone) catabolism genes and α-amylase (starch-hydrolyzing enzyme) genes, affecting their expression levels. Cold atmospheric plasma is known as an innovative and sustainable energy that has positive effects on the growth and development of many plant species. We, therefore, treated seeds that matured under heat stress with cold plasma and found that subsequent germination was significantly restored; genes involved in ABA biosynthesis (OsNCED2 and OsNCED5) were downregulated, whereas genes involved in ABA catabolism (OsABA8′OH1 and OsABA8′OH3) and α-amylase genes (OsAmy1A, OsAmy1C, OsAmy3B, and OsAmy3E) were upregulated. Cold plasma treatment caused significant hypermethylation of the OsNCED5 promoter and hypomethylation of OsAmy1C and OsAmy3E promoters, which matched their expression patterns. We suggest that cold plasma treatment can significantly improve the germination of rice seeds affected by heat stress by affecting epigenetic regulation.
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