Search results for " Plot"
showing 10 items of 233 documents
Concise review of interrill erosion studies in SE Spain (Alicante and Murcia): erosion rates and progress of knowledge from the 1980s
2005
From the 1980s onward studies on interrill soil erosion were intensified in SE Spain. The main achievements of the research carried out in the field areas of Alicante and Murcia concern: first, (1) the estimation of erosion rates directly in the field under a wide range of methodologies, different scales and different environmental conditions; (2) estimations based on existing models, such as the USLE, carried out for different subcatchments of the Segura and Júcar catchments; and (3) other parametric and physical event-based models have also been calibrated and validated. Second, the progress of the knowledge in understanding erosion mechanisms. New and reviewed concepts regarding mainly h…
Comment on “Determining soil erodibility for the USLE-MM rainfall erosion model by P.I.A. Kinnell”
2018
Abstract The measurements units of the USLE-MM soil erodibility factor are dependent on the exponent of the erosivity term. This circumstance prevents to compare soil erodibility values of sites differing by the value of this exponent. To overcame this problem, Kinnell (2018) suggested to relate the soil erodibility factor of the USLE-MM with that of USLE-M by a linear relationship with the objective to obtain a soil erodibility factor independent of the power of the erosivity term. The USLE-MB, which is a recently proposed model, has also a soil erodibility factor having measurement units common to USLE modelling environment. Kinnell (2018) also showed that the relationship between the pow…
Heart Rate Variability Monitoring during Interferential Current Application in the Lower Back Area: A Cross-Sectional Study
2021
Vasovagal reactions may occur occasionally during electrical stimulation using interferential current (IFC). The purpose of this study was to examine variations in autonomic activity during the application of IFC in asymptomatic participants by analysis of their heart rate variability (HRV). Seventy-three male volunteers were randomly assigned to a placebo group (n = 36
Characterization and properties of PEO coatings on 7075 Al alloy grown in alkaline silicate electrolyte containing KMnO 4 additive
2017
Abstract Plasma electrolytic oxidation (PEO) was used to modify the surface of 7075 Al alloy by applying a bipolar pulsed-current in a silicate based electrolyte containing 0 to 3 g L− 1 KMnO4. For the coating produced in the base electrolyte, crystalline γ-Al2O3 was the main phase, while the coatings formed at the presence of KMnO4 consisted of α-Mn2O3 containing Si and Al oxides. A pancake structure was observed on surface of the coating produced in the base electrolyte, while a foam feature along with some volcano-like areas was detected on the surface of the coatings produced in the presence of KMnO4. The KMnO4 changed the discharge type leading to diminish the pores at the metal/coatin…
The influence of pseudohalide ligands on the SIM behaviour of four-coordinate benzylimidazole-containing cobalt(ii) complexes.
2018
Three, mononuclear complexes of the formula [Co(bmim)2(SCN)2] (1), [Co(bmim)2(NCO)2] (2) and [Co(bmim)2(N3)2] (3) [bmim = 1-benzyl-2-methylimidazole] were prepared and structurally analyzed by single-crystal X-ray crystallography. The cobalt(ii) ions in 1-3 are tetrahedrally coordinated with two bmim molecules and two pseudohalide anions. The angular distortion parameter δ was calculated and the SHAPE program (based on the CShM concept) was used for 1-3 to estimate the angular distortion from an ideal tetrahedron. The molecules of 1-3 are effectively separated, and the values of the shortest distance of cobalt-cobalt are 8.442(6) and 6.774(8) A for 1, 10.349(8) and 10.716(8) A for 2 and 6.7…
Anodic growth of passive layers on steel rebars in an alkaline medium simulating the concrete pores
2006
Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques have been used to study passive layers anodically grown on steel rebars in an aqueous alkaline solution simulating the electrolyte of the concrete pores. Nyquist diagrams recorded by EIS at the different stabilization potentials show a diffusional tail at low frequencies. The analysis of the impedance measurements has been made by means of an equivalent circuit with a Warburg component and within the framework of the point defect model (PDM) theory. It is observed that the calculated concentration of vacancies is a function of the potential in accordance with the theoretical prediction of the PDM.
Oxidation mechanism of the Inconel 601 alloy at high temperatures
2010
The Inconel 601 alloy oxidation was performed in air, in the temperature range 1000-1150 °C, during 90 h. Kinetic results show that the parabolic behavior is always followed in this temperature range. The Arrhenius plot of the kp values shows two different activation energies. Between 1000 and 1050 °C the activation energy is E a1 = 160 ± 10 kJ/mol. In the 1050-1150 °C temperature range a higher value is calculated E a2 = 252 ± 20 kJ/mol. The E a2 value and the X-ray diffraction (XRD) results and scanning electron microscope (SEM) energy dispersive X-ray spectroscopy (EDS) examinations are in accordance with a scale growth mechanism limited by a growing Cr 2 O 3 scale acting as a diffusion …
Photoluminescence study of excitons in homoepitaxial GaN
2001
High-resolution photoluminescence spectra have been measured in high-quality homoepitaxial GaN grown on a free-standing GaN substrate with lower residual strain than in previous work. Unusually strong and well-resolved excitonic lines were observed. Based on free- and bound exciton transitions some important GaN parameters are derived. The Arrhenius plot of the free A exciton recombination yields a binding energy of 24.7 meV. Based on this datum, an accurate value for the band-gap energy, EG(4.3 K) = 3.506 eV, can be given. From the donor bound excitons and their “two-electron” satellites, the exciton localization energy and donor ionization energy are deduced. Finally, estimates of the ele…
Dielectric investigation of sodium potassium niobate ceramic doped 7% of antimony
2012
Abstract Electric properties of sodium potassium niobate ceramic doped antimony (Na0.5K0.5)(Nb0.93Sb0.07)O3 with sintering aid MnO2 (0.5 mol% MnO2) (KNNSbx + 0.5Mn) were investigated in a broad frequency (from 1 Hz to 54 GHz) and temperature (from 110 K to 800 K) ranges. The mean relaxation times calculated from the dielectric permittivity measurements fulfill Arrhenius relationship with dipole activation energy EA = 3409 K (EA/kB = 0.29 eV). The DC conductivity has been extracted from experimental results and the activation energy was calculated EA = 11733.78 K (EA/kB = 1.011 eV).
Constrained minimum variance control of nonsquare LTI MIMO systems
2010
Constrained minimum variance control is offered for nonsquare LTI MIMO systems. A constrained control design takes advantage of the so-called control zeros. The new control strategy is compared with familiar generalized minimum variance control and possible application areas of the two are discussed.