Potential Contours Research Articles

Verified solutions for the gravitational attraction to an oblate spheroid: Implications for planet mass and satellite orbits

Forces external to the oblate spheroid shape, observed from planetary to galactic scales, are demonstrably non-central, which has important ramifications for planetary science. We simplify historic formulae and derive new analytical solutions for the gravitational potential and force outside a constant density oblate. Numerical calculations that sum point mass contributions in a >109 element mesh confirm our equations. We show that contours of constant force and potential about oblate bodies are closely approximated by two confocal families whose foci (f) respectively are (9/10)½ae and (3/5)½ae for a body with f = ae. This leads to useful approximations that address internal density variations. We demonstrate that the force on a general point is not directed towards the oblate's center, nor are forces simply proportional to the inverse square of that distance, despite forces in the equatorial and axial directions pointing towards the center. Our results explain complex dynamics of galactic systems. Because most planets and stars have an aspect ratio >0.9, the spherical approximation is reasonable except for orbits within ∼2 body radii. We show that applying the “generalized” potential, which assumes central forces, yields J2 values half those expected for oblate bodies, and probably underestimates masses of Uranus and Neptune by ∼0.2%. We show that the inner Saturnian moons are subject to non-central forces, which may affect calculations of their orbital precession. Our new series should improve interpretation of flyby data.

Vibrational investigation on pharmaceutical activity of m-xylene-4-sulphonic acid by quantum computational and experimental support

ABSTRACTDetailed physical, chemical, thermal and circular vibrational investigations have been made on FT-IR, FT-Raman, NMR and UV–Visible spectra of m-xylene-4-sulphonic acid. The modification of the basic property of the base compound favoured by the asymmetric orientation of the charge levels among the atoms of the compound has been discussed in detail. The transitional pattern among the natural bond orbitals emphasized the inducement of the antibacterial and antifungal activity in the compound. Strong interpretations of the physical and chemical properties by intense observation using excitations between the electronic energy levels within the molecule have been carried out. The arrangement of the dipole moment of the bonds and the change of the resultant magnetic moment were observed from the average polarizability first-order diagonal hyperpolarizability. The receptor and inhibition property of the molecule were interpreted by the identification of reactive sites from the molecular electrostatic potential contour map. The chemical reaction continuity is keenly observed from thermodynamic analysis.

Theoretical Study and Experimental Analysis on 2-(1-Ethyl-4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)-2-oxoacetic Acid (3) Using the DFT Approach

Riley oxidation of 3-acetyl-4-hydroxyquinolin-2(1H)-one (1) with selenium dioxide furnished the unexpected product 2-(1-ethyl-4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)-2-oxoacetic acid (3). The expected product 2-(1-ethyl-4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl)-2-oxoacetaldehyde (2) was excluded based on the spectral data. The elemental analysis and spectral data (IR, and 1H NMR) was used to deduce the structure of compound 3. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations of the electronic structure at the B3LYP/6-311G (d,p) level of theory have been employed for compound 3 to investigated its geometry, linear polarizability 〈Δα〉, first-order hyperpolarizability 〈β〉, natural bonding orbital (NBO), molecular electrostatic potential contours (MEP and ESP), electrophilicity, and UV–Vis spectra in both ethanol and dioxane solvents. The geometrical and energetic parameters have been extensively investigated to reveal the reason behind the selective formation of compound 3, rather than the expected product 2. FT-IR spectra in the solid phase were recorded for compound 3. The thermo-chemical parameters, harmonic vibration frequencies, and the equilibrium geometries have been calculated at the DFT/B3LYP/6-311G (d,p) level. Time-dependent density functional theory (TD-DFT) was used to calculate the excited states of compound 3. Changes in the solvent cause changes in the band intensities and in the positions of the band maxima (λmax). The excited state was identified and contributes to the electronic configurations, and it was characterized in terms of the relevant MOs. The theoretical spectra were computed using the Coulomb-attenuating method (CAM-B3LYP), using the basis set 6-311G (d,p) in the gas phase, and the polarizable continuum model (PCM) in dioxane and ethanol. The results indicate good agreement with the observed spectra.

A GIS-based model of potential groundwater yield zonation for a sandstone aquifer in the Juye Coalfield, Shangdong, China

Resolving the potential groundwater yield zonation of sandstone aquifers occurring at depths of several hundred meters has been an important and challenging objective of the hydrogeological research focused on preventing flood hazards in coal mines. Using accessible geological exploration data we put forward a method of predicting the spatial distribution of groundwater storage potential in sandstone aquifers from Permian-age coal deposits in Juye Coalfield, Shangdong, China. A Geological, Tectonic and Lithological Composition Index (GTLCI) model was created using the following parameters: sandstone depth and thickness, faults length density (FaLD), faults density (FaD), fault frequency density (FaFD), fault scale density (FaSD), variation coefficient of the slope (VCS) of the coal seam, intensity index of folds in horizontal direction (IIFoH), and lithological composition index (LCI). Each of these factors was subsequently divided into 5 classes. The analytic hierarchy process (AHP) and trapezoidal fuzzy number (TFN) method was applied to calculate the weight of the conditioning factor and their respective sub-classes. Groundwater yield potential contour map, which was initially constructed using the GTLCI values revealed four groundwater abundance zones. The map was further refined by taking into account hydrogeologic data collected during mining activities. The GTLCI model predictive success rate of 80% was explained by the limited number of boreholes available for validation. It is considered that the GTLCI model is effective at predicting zonation of groundwater yield in the sandstone aquifers from Permian- age coal deposits in Juye Coalfield, China.

Erratum to: Sala L, et al. Action potential contour contributes to species differences in repolarization response to β-adrenergic stimulation

Erratum to: Sala L, et al. Action potential contour contributes to species differences in repolarization response to β-adrenergic stimulation

Action potential contour contributes to species differences in repolarization response to β-adrenergic stimulation.

Repolarization response to β-adrenergic (β-AR) stimulation differs between guinea-pig and canine myocytes and, within the latter, between myocardial layers. Correlative analysis suggests that this may be due to differences in action potential (AP) contour. Here we tested whether AP contour may set the response of current and of repolarization to β-AR stimulation (10 nM isoproterenol, ISO). The responses of AP and current to ISO were measured under I-clamp and "AP-clamp" in guinea-pig (GP), dog epicardial (DEPI) and dog subendocardial (DENDO) myocytes. Dynamic-clamp (DC) was used to evaluate the impact of AP features on AP response to ISO. ISO prolonged AP duration (APD) in GP myocytes, did not affect it in DENDO and shortened it in DEPI ones. The current induced by ISO (IISO) sharply differed between GP and canine myocytes and, to a lesser extent, between DENDO and DEPI ones. Differences in IISO profile likely important in setting APD response (time-to-peak, time-to-reversal), were minimized when canine myocytes where clamped with GP AP-waveforms and vice versa. Introduction of a "notch" in GP AP (by DC) was alone insufficient to affect the APD response to ISO; nevertheless, when incorporated in a GP AP-waveform, the main "canine" AP features ("notch" and low plateau potential) caused IISO of GP myocytes to acquire canine features. Early repolarization contour and level of plateau potential contribute to species-specificity of IISO profile. Changes in AP contour, also when generated by modulation of ISO-insensitive currents, may be crucial in setting APD response to β-AR stimulation.

Effects of electric field methods on modeling the midlatitude ionospheric electrodynamics and inner magnetosphere dynamics

AbstractWe report a self‐consistent electric field coupling between the midlatitude ionospheric electrodynamics and inner magnetosphere dynamics represented in a kinetic ring current model. This implementation in the model features another self‐consistency in addition to its already existing self‐consistent magnetic field coupling with plasma. The model is therefore named as Ring current‐Atmosphere interaction Model with Self‐Consistent magnetic (B) and electric (E) fields, or RAM‐SCB‐E. With this new model, we explore, by comparing with previously employed empirical Weimer potential, the impact of using self‐consistent electric fields on the modeling of storm time global electric potential distribution, plasma sheet particle injection, and the subauroral polarization streams (SAPS) which heavily rely on the coupled interplay between the inner magnetosphere and midlatitude ionosphere. We find the following phenomena in the self‐consistent model: (1) The spatially localized enhancement of electric field is produced within 2.5 < L < 4 during geomagnetic active time in the dusk‐premidnight sector, with a similar dynamic penetration as found in statistical observations. (2) The electric potential contours show more substantial skewing toward the postmidnight than the Weimer potential, suggesting the resistance on the particles from directly injecting toward the low‐L region. (3) The proton flux indeed indicates that the plasma sheet inner boundary at the dusk‐premidnight sector is located further away from the Earth than in the Weimer potential, and a “tongue” of low‐energy protons extends eastward toward the dawn, leading to the Harang reversal. (4) SAPS are reproduced in the subauroral region, and their magnitude and latitudinal width are in reasonable agreement with data.

Meandering Subtropical Jet and Precipitation over Summertime East Asia and the Northwestern Pacific

Abstract It has been revealed that in summertime, precipitation is enhanced to the south of the upper-level tropopausal potential vorticity contours, which are accompanied by instantaneous jets, over the eastern coastal region of China to the northwestern Pacific. It is frequently exhibited as precipitation bands ranging in size from over a thousand to several thousands of kilometers long. In this study, an analysis was conducted to quantify the relationship depending on the phase of upper-level disturbances. With composite analysis, it is shown that the enhancement along the contours occurs at all phases; it occurs not only to the east but also to the west of the upper-level troughs, although it is weaker. The midtropospheric distributions of upwelling and the Q-vector convergence are collocated with the precipitation enhancement, suggesting the importance of dynamical induction by geostrophic flow at all phases. The effects of upper-level disturbances and low-level jets (LLJs) with a southerly component are investigated by using an idealized nondimensional quasigeostrophic model supporting latent heating. While upper-level waves induce upwelling and downwelling to the east and west, respectively, of the upper-level troughs, LLJs tend to offset the downwelling, enabling precipitation to the west too. Both in the observational composite and the idealized model with LLJ, confluence and diffluence contribute to the Q-vector convergence to induce upwelling along the subtropical jet irrespective of upper-level disturbance phases. This induction is explained as a general feature of a veered jet where geopotential isolines rotate clockwise with height without requiring wind variation along the jet.

Piezoresponse force microscopy studies of domains in PbFe1/2Nb1/2O3 ceramics

ABSTRACTLi-doped PbFe1/2Nb1/2O3 ferroelectric ceramics was investigated by the Piezoresponse Force Microscopy (PFM) and Kelvin Probe Force Microscopy (KPFM) methods. Areas with principally different piezoresponse were observed at the PFM images. The stripe-like structures were revealed, which seem to be either 110±4° or 67±4° ferroelectric domains. The electric potential contours of the KPFM images demonstrate a significant discrepancy with the surface topography, which may be valuable for characterization of the samples.

Late sodium current and intracellular ionic homeostasis in acute ischemia.

Blockade of the late Na+ current (I NaL) protects from ischemia/reperfusion damage; nevertheless, information on changes in I NaL during acute ischemia and their effect on intracellular milieu is missing. I NaL, cytosolic Na+ and Ca2+ activities (Nacyt, Cacyt) were measured in isolated rat ventricular myocytes during 7min of simulated ischemia (ISC); in all the conditions tested, effects consistently exerted by ranolazine (RAN) and tetrodotoxin (TTX) were interpreted as due to I NaL blockade. The results indicate that I NaL was enhanced during ISC in spite of changes in action potential (AP) contour; I NaL significantly contributed to Nacyt rise, but only marginally to Cacyt rise. The impact of I NaL on Cacyt was markedly enhanced by blockade of the sarcolemmal(s) Na+/Ca2+ exchanger (NCX) and was due to the presence of (Na+-sensitive) Ca2+ efflux through mitochondrial NCX (mNCX). sNCX blockade increased Cacyt and decreased Nacyt, thus indicating that, throughout ISC, sNCX operated in the forward mode, in spite of the substantial Nacyt increment. Thus, a robust Ca2+ source, other than sNCX and including mitochondria, contributed to Cacyt during ISC. Most, but not all, of RAN effects were shared by TTX. (1) The paradigm that attributes Cacyt accumulation during acute ischemia to decrease/reversal of sNCX transport may not be of general applicability; (2) I NaL is enhanced during ISC, when the effect of Nacyt on mitochondrial Ca2+ transport may substantially contribute to I NaL impact on Cacyt; (3) RAN may act mostly, but not exclusively, through I NaL blockade during ISC.

Vibrational and NMR Investigation on Pharmaceutical Activity of 2,5- Dimethoxy-4-Ethylamphetamine by Theoretical and Experimental Support

The Detailed physical, chemical, thermal and circular vibrational investigations have been made on FT-IR, FTRaman, NMR and UV-Visible spectra of 2,5-Dimethoxy-4-ethylamphetamine. The modification of the basic property (deficit hyperactivity disorder) of the base compound (Amphetamine) is favoured by the insertion of two methoxy and ethyl-methyl groups have been discussed in detail. The transitional pattern among NBO emphasized the inducement of the psychedelic activity in the compound. The strong interpretation made on the physical and chemical properties by intense observation using excitations between the electronic energy levels within the molecule have been carried out. The arrangement of the dipole moment of the bonds and the change of resultant magnetic moment were observed from the average Polarizability first order diagonal hyperpolarizability. The receptor and inhibition property of the molecule were interpreted by the identification of reactive sites from molecular electrostatic potential contour map. The chemical reaction continuity is keenly observed from thermodynamical analysis.

Persistent landfalling atmospheric rivers over the west coast of North America

AbstractLandfalling atmospheric rivers (ARs) are linked to heavy precipitation and extreme flooding, and are well known along the western coast of North America. The hydrological impacts of ARs upon landfall are correlated with their duration and magnitude. In order to improve the forecast of these hydrologically significant landfalling events, a better understanding of how they differ from other landfalling events must be established through an investigation of the mechanisms leading to their development prior to landfall. A subset of persistent landfalling AR events between 30°N and 50°N is identified in 3‐hourly Modern‐Era Retrospective Analysis for Research and Applications reanalysis and validated against existing data sets. These events are identified as features in the low troposphere with high moisture transport and extended geometry that persist over a limited region of the coastline for longer than 63 h (85th percentile of AR duration). A composite analysis shows that persistent events have distinct thermodynamical and dynamical characteristics compared to all AR events. They are characterized by greater moisture content, suggestive of Pineapple Express‐type events, a perturbed upper level jet and anticyclonic overturning of potential vorticity contours associated with anticyclonic Rossby wave breaking. Moreover, the location of the Rossby wave breaking is shifted inland compared to all AR events. Analogue analysis of the 500 hPa geopotential height anomalies is used to find nonpersistent events with similar dynamical characteristics to persistent events. Despite their similarity to persistent events, nonpersistent analogues show very little shift toward longer duration. A comparison of the development of persistent and nonpersistent analogues shows that persistent events have much greater moisture content.

Practical Theology from the Perspective of Catholic Spirituality: A Hermeneutic of Discernment

Abstract This article examines practical theological hermeneutics through the lens of Catholic spirituality. Key to understanding the movement from description to analysis to revised praxis is the ways in which interpretive communities understand the connections between divine reality and human reality. In light of this, the article explores the relationship between epistemology and pneumatology found within Christian tradition by proposing an approach to practical theological hermeneutics rooted in the Ignatian practice of spiritual discernment. By doing so, this article seeks to contribute the potential contours of a distinctive Roman Catholic contribution to practical theology, and in a broader sense, show how the practice of discernment presents studies and methods in practical theology with a way of understanding connections among practical wisdom, habitus, research, and theological interpretation.

Geophysical analysis of the Alpha–Mendeleev ridge complex: Characterization of the High Arctic Large Igneous Province

The Alpha–Mendeleev ridge complex is a first-order physiographic and geological feature of the Arctic Amerasia Basin. High amplitude “chaotic” magnetic anomalies (the High Arctic Magnetic High Domain or HAMH) are associated with the complex and extend beyond the bathymetric high beneath the sediment cover of the adjacent Canada and Makarov–Podvodnikov basins. Residual marine Bouguer gravity anomalies over the ridge complex have low amplitudes implying that the structure has minimal lateral density variability. A closed pseudogravity (magnetic potential) contour around the ridge complex quantifies the aerial extent of the HAMH at ~1.3×106km2.We present 2D gravity/magnetic models for transects across the Alpha Ridge portion of the complex constrained with recently acquired seismic reflection and refraction data. The crustal structure is modeled with a simple three-layer geometry. Large induced and remanent magnetization components were required to fit the observed magnetic anomalies. Density values for the models were based on available seismic refraction P-wave velocities. The 3000kg/m3 lower crustal layer is interpreted as a composite of the original crustal protolith and deep (ultramafic) plutonic intrusions related to a plume sourced (High Arctic) LIP. The 2900kg/m3 mid-crustal and 2600kg/m3 upper-crustal layers are interpreted as the combined effect of sills, dikes, and flows. Volumetric estimates of the volcanic composition include (at least) 6×106km3 for the mid- and upper-crust and between 13×106 and 17×106km3 within the lower crust — for a total of ~20×106km3.We compare the magnetic structure, pseudogravity, and volumetric estimates for the HAMH portion of the HALIP with global large igneous province analogs and discuss implications for Arctic tectonics. Our results show that the closest analog to the HAMH/HALIP is the Kerguelen Plateau, which is considered a continental plateau intensively modified by plume-related volcanism.

Potential Contour Ensembles

In the paper a contour ensemble image segmentation concept is presented. It bases on the previously observed relationship between contours and classifiers. Because of the specificity of the active contour segmentation the method requires a special procedure to obtain ensemble members with desired properties. In this work it is achieved by early stopping of randomized optimization algorithm. The results of the method are illustrated with a practical problem of heart ventricle segmentation by means of active potential contours. Automatically found contours may be of use in a process of pulmonary embolism diagnosis.

Nanostructural adsorption of vanadium oxide on functionalized graphene: a DFT study.

Rutile-monoclinic phase transitions of vanadium oxide (VO2) nanocrystals adsorbed on graphene-based substrates are of current scientific interest, although their adsorption and growth mechanisms have not been investigated theoretically. In this study, we use density functional theory (DFT) calculations for determining the binding energies and predicting the corresponding directions of growth of VO2 nanostructures (rutile and M1-monoclinic) interacting with both pure graphene and functionalized graphene nanoribbons. Several adsorption sites of pure graphene including the top, bridge, and hollow sites are considered, while additional adsorption sites of functionalized graphene nanoribbons, epoxy, alcohol and carboxylate are investigated. Vanadium oxide nanostructures are found to favor physical adsorption on the hollow sites of pure graphene, while chemical adsorption is favored on the carboxylate sites of functionalized graphene nanoribbons (FGNRs). Charge density maps showed the electron distribution originating from the interaction between VO2 and graphene substrates, helping to understand the mechanism of charge transfer. Electronic local potentials showed vertical growth tendencies for rutile VO2, while M1-monoclinic VO2 showed horizontal growth tendencies. Partial density of states (PDOS) helped examine the electronic structure of metallic rutile VO2 binding to hollow and carboxylate sites of functionalized graphene. These results provide an improved understanding of the controlled and oriented growth of VO2 nanocrystals on graphene-based substrates which can enable various properties such as the metal-insulator transition (MIT) of VO2 in light regulation applications.

Conformational, vibrational spectroscopic, nonlinear optical activity, and structure–activity studies on 2-hydroxy-3,5-dinitropyridine: Combined experimental and density functional theory approach

ABSTRACTThe conformational analysis was carried out to predict the most stable, optimized structure of 2-hydroxy-3,5-dinitropyridine among various conformers. The most stable, optimized structure of the molecule was predicted by the density functional theory (DFT) using the B3LYP method with the cc-pVQZ basis set. The vibrational frequencies, natural atomic charge distribution, and thermodynamic properties were calculated. The molecular electrostatic potential surface and contour map were simulated. The experimental and theoretical vibrational frequencies were assigned on the basis of potential energy distribution calculation. The density of states (DOS) spectrum was simulated. The frontier molecular orbital analysis was carried out. The natural bond orbital (NBO) analysis was performed to evaluate the donor–acceptor interactions in the molecule. The structure–activity descriptors were determined by Fukui functions and local reactivity descriptor calculations. The nonlinear optical (NLO) activity of the molecule was studied. The second harmonic generation test confirms the NLO activity of the title molecule.

Terrain Correction in the Gradient Calculation of Spontaneous Potential Data

AbstractTerrain correction is to eliminate the effect of terrain relief around measurement points on observation results in gravitational and geoelectrical prospecting. Because the microscopic mechanism of spontaneous potential anomalies formed by terrains is rather complex, it is difficult to obtain an analytic formula, whereas a more intuitive method can be adopted instead to find out the fitting formula between these two variables. According to the study, in spontaneous potential gradient calculation, spontaneous potential anomalies caused by topography can be divided into two types: one is that anomalies have a mirror‐image relation with terrain relief, which accounts for the majority of cases; the other one is that anomalies have an inverted mirror‐image relation with terrain relief. The relation between a majority of anomalies and terrain relief could be linear, quadratic or exponential, among which linear relation is the primary. As for which fitting relation should be adopted specifically, it can be decided by selecting a typical terrain and spontaneous potential curve first and judging through the law of variations; and trial calculation method can be adopted as well to choose the appropriate fitting formula by comparing the correction effects.The Ordos Basin was selected to be the research site in this paper and the terrain correction method which is applicable to spontaneous potential gradient calculation was put forward. Through the comparison of the correction results of three kinds of fitting formulas, it was concluded that the linear fitting formula can better describe the relationship between relative height and spontaneous potential correction amount in the surveyed area. Terrain correction can effectively eliminate the correlation between relative height and spontaneous potential. The corrected spontaneous potential curves can reflect subsurface geological structure better, and the anomalies showed by the spontaneous potential contour map can be more prominent. Terrain relief can influence the appearance of anomalies in spontaneous potential gradient calculation, especially when the area of rugged terrain is comparable to the area of target geological bodies, which may make it difficult to distinguish these two anomalies. Thus the study on terrain correction has great importance in practice.

Spectroscopic investigation and chemical properties analysis on anticancer compound; α,α,ά,ά-Tetrabromo-p-Xylene with computational analysis

In order to explore the pharmaceutical applications, the vibrational spectra of α,α,ά,ά-Tetrabromo-p-Xylene (4αBX) were recorded using IR, Raman and NMR spectrometer with FT technique. The modified optimized structural bond parameters and vibrational group wavenumbers of molecule based on substitutional bonds, Mulliken atomic charge distribution, frontier molecular orbital levels, chemical properties, temperature dependence of thermodynamic parameters, NLO studies and natural bond orbital calculations of the molecule were performed using the HF and DFT model theories. The intense observation was made over the excitations between the electronic energy levels within the molecule which enable to explore the electronic properties. The distribution of Mulliken charges of present molecule were calculated and were interrelated with the architecture of the molecular bonds. The charge transformation over the frontier molecular orbitals between the ligand and rings has been thoroughly observed. The average Polarizability first order diagonal hyperpolarizability have been calculated and from which the linear and non linear optical activity of the molecule is interpreted in detail. The reactive site of the molecule was predicted from the molecular electrostatic potential contour map. From the thermodynamical analysis, it was found that, the values of thermo dynamic parameters were increasing with increasing temperature.

Vibrational Spectroscopic and Structural Investigations of 2-Amino-6-Methoxy-3-Nitropyridine: a DFT Approach

The conformational analysis of 2-amino-6-methoxy-3-nitropyridine molecule (AMNP) has been carried out using density functional theory calculations. The vibrational spectra of the molecule is simulated theoretically and compared experimentally, and the vibrational frequencies are assigned on the basis of potential energy distribution calculations. Electronic properties of the molecule derived from the theoretical ultraviolet–visible spectrum are validated experimentally. The higher non-linear optical activity of the molecule is indicated in the first-order hyperpolarizability calculations. The natural bond orbital and Mulliken atomic charge distribution analysis confirm intramolecular charge transfers and intramolecular interactions. The Frontier molecular orbitals are plotted, and the related molecular properties are calculated and discussed. The molecular electrostatic potential contour map is simulated. As the presence of intramolecular interactions and the associated charge transfers between the pyridine ring of AMNP molecule and the lone pair of oxygen is a common molecular feature of a pharmaceutical compound, this investigation paves the way for its possible biomedical applications. Further, the considerably higher non-linear optical (NLO) activity of the molecule identified suggests its potential applications in the design of new optical materials.