Effect of Ground Proximity on Aerodynamic Characteristics of NACA 4412 Airfoil.

Ground effect plays a vital role in modulating the flow behavior over any streamlined body. The most widely used wing-in ground effect (WIG) aircrafts and seaplanes utilize this phenomenon in order to enhance the aerodynamic performance during the landing and take-off phases of flight. This paper investigates the aerodynamics of ground effect on a NACA 4412 rectangular wing without end plates. The experiment was conducted in a low-speed wind tunnel at Re=2×105 for the ground clearance of 1 and 0.5 of the chord, measured from the maximum thickness position on the airfoil. The pressure distribution over the chord length was recorded for α=3° and 6° to verify the effect of ground clearance during takeoffs. The results have shown to be in good accordance with the literature, as the coefficient of lift augmented with increase in ground proximity and the induced drag was minimized.

Numerical simulation and calibration of a single seam WAAM process with a commercial and an open source software

This paper is dealing with the comparison of the FEM result quality between a commercial tool and an open source software with regards to the numerical simulation of a single seam WAAM process. For this purpose, an experimental WAAM process was conducted by a welding robot on a 1.4404 (316L) base plate with a 1.4404 (316L) welding wire, connected with the associated measurement equipment. Furthermore, the equivalent setup was transferred in the FEM tools Simufact Welding and Elmer FEM, using the same parameters for both simulations. The calculations show, that both programs are able to generate high quality results with a good accordance to the temperature development within the experimental processes. In summary it can be said, that both programs offer advantages and the decision what tool has to be used depends on the requirements and the possibilities of the user.

Analysis of physical activity effects on plasma glucose–insulin system dynamics: A mathematical model

The main objective of this paper is to understand and analyse the effect of physical activity on plasma glucose and plasma insulin levels through mathematical modelling. Energy for the human body during physical activity is provided by glucose as sugar, while insulin as hormone supports the absorption of this glucose. Furthermore, glucose and insulin are interrelated physiologically by some parameters that we estimate mathematically by using nonlinear optimization and data collected in Rwanda. Research in this direction has been done by, for example Anirban and colleagues, who developed a dynamic model of exercise effect on plasma glucose and insulin levels. As a benchmark, the results of numerical simulation obtained in this paper have been compared with those of Anirban and colleagues to test the efficiency of our mathematical model. We have concluded that the results of those two separate mathematical models are in good accordance and that the proposed mathematical model allows further investigation of the effects of physical activity on the dynamics of the glucose–insulin system. Moreover, we have implemented a particle filtering algorithm for estimation of glucose and insulin in internal parts of the body such as heart and liver by using measurements from peripheral tissues as noisy data because taking blood samples from all parts of the body is practically and clinically impossible.

Numerical Validation of the Radiative Model for the Solar Cadaster Developed for Greater Geneva

The achievement of the targets for reducing greenhouse gas emissions set by the Paris Agreements and the Swiss federal law on the reduction of greenhouse gas emissions (CO2 law) requires massive use of renewable energies, which cannot be achieved without their adoption by the general public. The solar cadaster developed as part of the INTERREG G2 Solar project is intended to assess the solar potential of buildings at the scale of Greater Geneva—for both industrial buildings and for individual residential buildings—at a resolution of 1 m. The new version of the solar cadaster is intended to assess the solar potential of roofs, as well as that of vertical facades. The study presented here aims to validate this new version through a comparison with results obtained with two other simulation tools that are widely used and validated by the scientific community. The good accordance with the results obtained with ENVI-met and DIVA-for-Rhino demonstrates the capability of the radiative model developed for the solar cadaster of Greater Geneva to accurately predict the radiation levels of building facades in configurations with randomly distributed buildings (horizontally or vertically).

Higher order TN approximation for the neutron diffusion problem in a slab reactor

Higher order approximations of the Chebyshev polynomials of first kind (TN) are used for the first time in calculation of the diffusion lengths of monoenergetic neutrons in a homogeneous slab. In the method, the diffusion lengths of the neutrons are calculated using various values of the c, the number of secondary neutrons per collision. First, the traditional Legendre polynomials (PN) approximation and then the present TN method are used separately. The numerical results for the diffusion lengths are tabulated in the tables up to an order of N = 9. A brief comparison is also done between the results obtained from the present method and the ones in literature. The advantages of the present method can easily be observed from the good accordance between results given in the tables for comparison and its easily executable equations. For many of the c values, the results obtained from TN method are better than the results obtained from PN method.

First-Principles Study on the Mechanism of Greenhouse Gas Generation in Aluminum Electrolysis

Greenhouse gases emitted by the aluminum electrolysis industry have brought great challenges to environmental protection. To address this problem, understanding the micro-generation mechanism of greenhouse gases in the electrolysis process is of great significance to their source suppression. Based on the first principles calculation method, the formation paths of CO, CO2 and COF2 during normal electrolysis were obtained by studying the adsorption behavior of oxygen and fluorine complex anions (short for [O]2−, [F]−) on the anode surface in cryolite alumina molten salt. The calculation results indicate that the O and F atoms prefer to adsorb at bridge site 1 of Model A, with the adsorption energies of −4.82 eV and −3.33 eV. In the [O]2− priority discharge stage, Path 3 is the most likely path for CO2 generation, while in the [O]2−, [F]− co-discharge stage, Path 3 is the most likely path for COF2 generation. It is deduced that the thermal decomposition of COF2 at high temperature should account for the generation of CF4 with a low concentration of the so-called non-anode effect PFC (NAE-PFC). Experiments were also conducted to verify the calculation by disclosing the bonding information of C, O and F, which are in good accordance with the results calculated by the first principle.

Stability assessment of maize hybrids by different methods in relation to their zoning

A many-sided evaluation of grain yield stability of 22 maize hybrids from the early group (FAO 300-400), tested in 4 locations was done. Different methods and models were applied: variation and regression analysis; AMMI and cluster analysis as well. A modified method for grouping of hybrids by mean yield and mean values of the regression coefficient bi was proposed. A good accordance between that method and AMMI-1 analysis was observed. The cluster analysis also confirms this consent. Calculated theoretical yields by locations create conditions for more precise zoning of hybrids according to environments.

Development and Validation of Bioanalytical UV-Spectrophotometric Method for Determination of Candesartan and Development and Validation of UV-Spectrophotometric Method for Determination of Candesartan in Bulk Drug and Formulation

The accurate, precise, sensitive and economical spectrophotometric bioanalytical method was developed and validated for estimation of candesartan in plasma. The UV method was also employed for estimation of candesartan in bulk drug and in dosage form. The absorption maximum found for candesartan was 245nm. The correlation coefficient was found to be 0.999. The mean recovery for candesartan was found to be 99.92%. The developed method was validated according to ICH guidelines and values of accuracy, precision and other statistical analysis were found to be in good accordance with the prescribed values. Thus the proposed method was successfully applied for estimation of candesartan in plasma and for routine industrial work.

Determination of Dislocation Density and Correlation Length of Si, Ti, Au and Zno on Ge by Peak Profile

In this study, X-ray diffraction peaks of Si, Ti, Au and ZnO grown on Ge substrate with thickness of 500 nm by using sputtering method are analyzed to determine correlation length and dislocation density. It is seen that in most dense region of peaks, peak behaviour is in accordance with Gauss function. Right and left tails of peaks are in good accordance with q3 law. For randomized dislocations, obeying q3 law is typical and they can be monitored with w-scans by using open detectors. Whole profile is fitted with a limited dislocation dispersion. Edge dislocation density and correlation length are determined in the degree of 1010cm-2 and 103 nm, respectively. In order to gain these values, semi-experimental equations in Kragner method are used. For making a good fit, fit iteration step is taken as 9x106.

Orthocorrection of KH-5 ARGON Satellite Imagery of Aral Sea

Declassified Intelligence Satellite Imagery is a unique source of historical environmental data. Three consecutive and overlapping images of the ARGON, the first dedicated mapping mission from 1962 depicting the surrounding of the Aral Sea were orthocorrected using Ground Control Points. As ARGON mission had a frame type camera, a least squares estimation of exterior orientation parameters were estimated using space resection. A modified space resection algorithm was used to estimate (beside the exterior orientation) the camera principal point coordinates and lens distortion correction coefficients. The overall accuracy of the orthocorrected images are in good accordance with the results of other authors.