Symmetry Factor Research Articles

Identification of geomorphic signatures of active tectonics in the Wadi Hagul Basin, Northwest Gulf of Suez, Egypt: insights from SRTM derived geomorphic indices and watershed analysis

The satellite data, include Landsat 7 Enhanced Thematic Mapper (ETM+), Landsat-8 (OLI), Shuttle Radar Topography Mission (SRTM), were processed and interpreted for creating an integrated geospatial map of the geomorphic indices (GI) of Wadi Hagul Basin (WHB). The present study is considered new, useful, and valuable in northwest of Gulf of Suez region to evaluate active tectonics using SRTM resulting drainage network and GI. Where fairly slight studies on active tectonics recognized on GI were prepared in the investigated area. The GI includes; Ratio of valley floor width to valley height (Vf), Transverse topographic symmetry factor (T), Stream length-gradient index (SL), Drainage basin shape (Bs), hypsometric integral (Hi), geomorphological landform and watershed analysis. Also, GI were integrated and combined with the seismic and structural lineaments intensities maps to create an integrated single index map. The morphotectonic geo-spatial distribution hazards map reveals that the high risky area is 82.75% of the total area, the moderate-risk area is 16.51%, and the low risky morph-tectonic area is 0.81%. Based on this map, it is necessary for planners and decision makers to extremely study attractive applicable action concerning the recommended mitigation measurements from this study to avoid any serious future problems in WHB and its surroundings areas.

Exploring neotectonic activity in a semiarid basin: a case study of the Ain Zerga watershed

AbstractMediterranean basin exposed to ongoing processes of erosion and deformation. Neotectonics is the study of the geological processes involved in the deformation of the Earth’s crust. The topography of the terrain is greatly impacted by these neotectonic events, which has a considerable impact on the drainage pattern and general geomorphology of the region. In this work, the active tectonics were evaluated using the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) and several Geomorphic Indices in the Ain Zerga region of Northeast Algeria. Asymmetry factor, basin form, the ratio of valley floor width to valley height, the sinuosity of mountain fronts, hypsometric integral, hypsometric curve, and transverse topographic symmetry factor were some of the indices used. These findings emphasize the tremendous tectonic activity that exists in the study area. In comparison to sub-watershed N°2, sub-watersheds N°1, N°3, and N°4 had stronger tectonic activity, according to the examination of these geomorphic indicators. The Relative Tectonic Activity Index (Iat) distribution pattern, which concurred with other pieces of information such as stream deflection and lineament analysis, corroborated these conclusions. We were able to learn a lot about the different levels of tectonic activity in the sub-watersheds by using traditional geomorphic indices. The tectonic activity-exhibiting basins consistently displayed connections with structural disturbances, basin geometry, and field research. Geomorphic indices and morphometric characteristics were used to identify tectonically active zones in a portion of the Mellegue transboundary basin, which shows a considerable influence of neotectonic activity in a portion of the Neogene basin.

Monitoring linear accelerator beam with daily quality assurance phantom

This paper aims to analyze the output constancy of a medical linear accelerator using PTW, and to study the suitability as a daily quality assurance device. It is assumed that the device is sensitive enough to detect minor variations in central axis beam, flatness, symmetry, and beam quality factor. PTW, QUICKCHECKwebline is the most efficient wireless device used in daily quality assurance. The measurements of output doses of photons ( 6MV and 15 MV) and electrons (6,9,12, and 15MeV) from a medical linear accelerator before the daily treatment have been graphically analyzed. This study assures the output stability of Varian Clinac iX 2100 CD linear accelerator at Bhaktapur Cancer Hospital, Bhaktapur, Nepal. The beam flatness, symmetry, beam quality factor, and central axis of photon and electron beam have been analyzed for 10x10cm2 and 20x20cm2 field size in separate ways. Among the measurements, observed parameters lie under the tolerance limit as recommended by American Association of Physicists in Medicine viz. ±3%. The outcomes of the measurements are in the acceptable range for the treatment procedure of patients.

Application of TOPSIS model in active tectonic prioritization: Madeira watershed, South America

The Andes orogenic belt is one of the most tectonically active zones located between the convergent margins of the South American plate and the Pacific plate. From the dissected western belt to the expanded alluvial plain of Amazon basin, the Madeira watershed bears recent tectonic imprints. The tectonic signature is well documented by the spatial and linear characteristics of the five sub watersheds along with the Madeira trunk river and channels. The level of tectonic activeness has been assessed on the sub watersheds of the Madeira River, which is one of the main right-hand tributaries of the Amazon River. On the five defined sub-watersheds and the main channel watershed of Madeira, several morphometric indices, viz., asymmetry factor (AF), tilt angle (β), sinuosity index (SI), channel concavity (ɵ), elongation ratio (Re), circularity ratio (Rc), transverse topographic symmetry factor (T) and basin shape index (Bs), have been used. To rank the watersheds based on tectonic activity, we applied the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) The active tectonics was also tested by a comparative study of linear indicators as Hack profiles, longitudinal profiles and segment-wise stream gradient index (SL) of watersheds 2 (rank 1) and 3 (rank 6). The results reveal that the most tectonically active watershed 2 is located in a high seismic magnitude zone with several deep earthquake epicenters. The least tectonically active watershed 6 is located in a low seismic zone.

Transverse momentum decorrelation of the flow vector in Pb–Pb collisions at sqrt{s_{_{textrm{NN}}}} = 5.02 TeV

Anisotropic flow, typically defined as the azimuthal correlations of the produced particles with respect to the common symmetry plane over a large kinematic, has been a popular approach in the last three decades to explore the properties of hot and dense QCD matter in high-energy heavy-ion collisions. These flow studies are usually based on the multi-particle correlations method, assuming that multi-particle correlations can be factorized into the product of flow coefficients. However, recent LHC measurements, based on new four-particle correlation observables, show evidence of flow angle decorrelation and flow magnitude decorrelation. These decorrelations break the assumption of the common symmetry plane and factorization. In this paper, we perform systematic studies to investigate the decorrelation with A Multi-Phase Transport (AMPT) model. We examine different tunings of the initial conditions, partonic cross sections, and hadronic interactions, revealing that the decorrelations are mainly driven by the initial geometry fluctuations while weakly influenced by the system’s dynamic evolution. Comparison to experimental data and the AMPT calculations presented in this paper promotes a new possibility to further constraints on the initial conditions of the heavy-ion collisions.

Morphometric parameters of the relief and drainage network of a tropical subbasin

This research analyzed the morphological/morphometric parameters of the relief and drainage network of the Formiga River subbasin, southern Minas Gerais State, Brazil. This study identified and examined the influences of control mechanisms in the development of current configurations. The methodology was based on the application of indices and parameters: (1) slope length (Hack's Sl); (2) normalized slope index (ksn); (3) river hierarchy; (4) drainage density; (5) hydrographic density; (6) sinuosity index; (7) density of structural lineaments; (8) transverse topographic symmetry factor; (9) asymmetry factor of drainage basins; (10) topographic profiles transverse to the valleys; (11) relief ratio; (12) roughness index; (13) roughness concentration index; (14) compactness coefficient; (15) circularity index and (16) form factor. The results indicated 3 sectors of the subbasin with distinct geomorphic behaviors, which resulted in peculiar surface structures and divergent current dynamics. The subbasin presents physical evidence that demonstrates and corroborates strong tectonic and structural control in the development of the current drainage network and relief. Human action has also affected, from the construction of dams, the dynamics of the lower course of the river, drowned by the reservoir of the hydroelectric plant of Furnas.

Halide-assisted differential growth of chiral nanoparticles with threefold rotational symmetry

Enriching the library of chiral plasmonic nanoparticles that can be chemically mass-produced will greatly facilitate the applications of chiral plasmonics in areas ranging from constructing optical metamaterials to sensing chiral molecules and activating immune cells. Here we report on a halide-assisted differential growth strategy that can direct the anisotropic growth of chiral Au nanoparticles with tunable sizes and diverse morphologies. Anisotropic Au nanodisks are employed as seeds to yield triskelion-shaped chiral nanoparticles with threefold rotational symmetry and high dissymmetry factors. The averaged scattering g-factors of the l- and d-nanotriskelions are as large as 0.57 and − 0.49 at 650 nm, respectively. The Au nanotriskelions have been applied in chiral optical switching devices and chiral nanoemitters. We also demonstrate that the manipulation of the directional growth rate enables the generation of a variety of chiral morphologies in the presence of homochiral ligands.

Coupling covariance matrix adaptation with continuum modeling for determination of kinetic parameters associated with electrochemical CO2 reduction

Coupling covariance matrix adaptation with continuum modeling for determination of kinetic parameters associated with electrochemical CO2 reduction

Experiments and discrete element simulations of crack initiation angle of mixed-mode I/II in PMMA material

Complex crack configuration causing mixed-mode I/II usually occurs in various situations in engineering, and it is difficult to accurately predict the direction of crack initiation by theory. In fact, there is a great difference between the finite-plate theoretical prediction and the experimental results. To investigate the effects of crack configuration on crack initiation angle, new brittle polymethyl methacrylate (PMMA) specimens were designed. Multiple sets of fracture experiments of mixed-mode I/II were performed systematically to obtain the crack initiation angle of PMMA specimens. The variation of the crack initiation angle with the size ratio was obtained experimentally, which indicated that the crack initiation angle increases with the increase of the size ratio. As a supplement to the physical experiments, corresponding numerical simulations were carried out based on the Discrete Element Method. Firstly, the material parameters of the numerical simulation were calibrated by reproducing the failure process of the sample in the experiment. Then, the numerical modeling and calculation were carried out for the samples that are inconvenient to process in the experiment. Combining the results of both experiment and numerical simulation, a prediction formula for the crack initiation angle was obtained. Furthermore, the effects of symmetry factor and preexisting crack length on the tensile capacity and the crack initiation angle were investigated by simulation systematically. By adjusting the crack configuration parameters, the direction of crack initiation can be artificially controlled, which is of great importance for ensuring engineering safety.

Hierarchies of RG flows in 6d (1, 0) massive E-strings

We extend the analysis of [9] to the 6d (1, 0) SCFTs known as massive E-string theories, which can be engineered in massive Type IIA with 8 − n0< 8 D8-branes close to an O8− (or O8* if n0 = 8, 9). For each choice of n0 = 1, …, 9 the massive {E}_{1+left(8-{n}_0right)} -strings (including the more exotic {overset{sim }{E}}_1 and E0) are classified by constrained E8 Kac labels, i.e. a subset of Hom(ℤk, E8), from which one can read off the flavor subalgebra of {E}_{1+left(8-{n}_0right)} of each SCFT. We construct hierarchies for two types of Higgs branch RG flows: flows between massive theories defined by the same n0 but different labels; flows between massive theories with different n0. These latter flows are triggered by T-brane vev’s for the right SU factor of the SCFT global symmetry, whose rank is a function of both k and n0, a situation which has so far remained vastly unexplored.

Morphotectonic Analysis of Wadi Al-Batin Alluvial Fan, South of Iraq, Using Remote Sensing and GIS Techniques

This research aimed to know the tectonic activity of the Wadi Al-Batin alluvial fan using hydrological and morphotectonic analyses. Wadi Al-Batin alluvial fan is deposited from Wadi Al-Rimah in Saudi Arabia, which extended to Iraqi and Kuwait international boundaries. The longitudinal and transverse faults that characterize this region were common. The Abu- Jir-Euphrates faults have a significant impact on the region. The faults zone consists of several NW- SE trending faults running from the Rutba in western Iraq to the south along the Euphrates through Kuwait and meeting the Al-Batin fault to the Jal Al-Zor fault. The Hydromorphometric analysis of the present fan shows five watersheds having asymmetry shapes, more elongated and activity from the elongation ratio and asymmetry factor values. In contrast, transverse topographic symmetry and mountain front sinuosity factor have moderate to low activity from the stream length gradient index. The morphotectonic analysis suggests that the Wadi Al-Batin alluvial fan has a moderate tectonic activity due to the tectonic activity of the subsurface lineaments and the oil field activities found in the region.

Evaluation of Active Tectonic Features of Nandakini River Basin, Lesser Himalaya, India by Using Morphometric Indices: A GIS Approach

Tectonic geomorphology has been evidenced as an essential tool to define and measure recent tectonic deformation. The Nandakini River originates from Nanda Ghunti glacier at 6886 m in Lesser Himalaya. It covers about ~551 km&lt;sup&gt;2&lt;/sup&gt; basin area, with a fourth-order stream. It confluences with the Alaknanda River near Nand Prayag (at elevation 852 m), Chamoli district of Uttarakhand. The drainage pattern is predominantly dendritic in the study area. The morphotectonic indices are measured to know the tectonic activity of the drainage basin. Morphometric indices reflecting hypsometric Integral is 1.07, indicating a deeper incision and a slight erosion. The basin elongation ratio is 0.17, suggesting that the area is tectonically active. The drainage basin asymmetric factor (44) suggest tilting. In addition, the drainage basin shape (3.27) indicates the basin is tectonically strong, the transverse topographic symmetry factor (0.31) indicates the asymmetric nature, the valley floor width to valley height ratio is 0.54 shows the deep, narrow valleys, and Active V-shaped incision. Stream longitudinal profile showing the area tectonically influenced. The Sinuosity Index of 1.12 suggests that low sinuous nature. The Stream length-gradient Index is 10.64, indicating high tectonic activity in valleys and basin areas. The transverse profile helps to understand the tilting of the basin. The Surface profile shows irregularity, and the linear trend of the profile shows the tilting of the basin. River carrying capacity with large boulder-size sediment indicates youth stage and tectonically active environment. The morphotectonic indices suggest that the drainage basin was affected by the regional structures and the present tectonics.

A Hybrid Analytical Model for the Electromagnetic Analysis of Surface-Mounted Permanent-Magnet Machines Considering Stator Saturation

This article presents the process of building a hybrid analytical model (HAM) for surface-mounted permanent-magnet machines. The HAM couples a reluctance network (RN) model in the stator region with a magnetic scalar potential analytical model in the air gap and magnets regions. This hybrid model can deal with the slotting effect with straight teeth, and takes magnetic saturation into account in the stator iron material using the RN model. It is calculated under open-circuit and loaded conditions. The magnetic flux density, flux linkage, back electromotive force (EMF), and torque of the machines are also calculated. This hybrid model is compared with the subdomain method. It is also compared with the finite element method (FEM) both in terms of the size of the matrix that needs to be calculated and in terms of the torque error. We analyzed this method for two surface-mounted permanent-magnet machines, one with a symmetry factor of four and another with a symmetry factor of three. In both cases, HAM reduced the size of the matrix that needed to be solved compared to FEM. In the machine with a symmetry factor of three, when the matrix size of both FEM and HAM was around 1700 × 1700, the torque error of FEM was 2.62% compared to the high-mesh-density FEM simulation, while the torque error of HAM was only 0.17% compared to the same simulation. HAM also had significant advantages over the subdomain method, as it reduced the torque error from 16.8% to 0.08% in the case of high magnetic saturation. The HAM can, hence, play a significant role in the design and optimization of surface-mounted permanent-magnet machines, especially in cases where magnetic saturation is present.

Особенности движений глаз в задаче зрительного поиска в зависимости от вербализуемости и симметричности стимулов

Background. Visual search is considered today as an active process, usually implemented with the participation of eye movements. Modern search models assume the influence of both stimulus and cognitive variables on its characteristics and effectiveness. However, in research, as a rule, only one type of variables is controlled, which requires the creation of new experimental paradigms that allow studying the influence of both types of factors and their interaction. Objective. Investigation of the influence of factors of verbalizability and symmetry of the target stimulus on the effectiveness and speed of its search and characteristics of search eye movements. Methods. The created stimuli were identical in basic stimulus characteristics (color, shape, size, slope, number of elements) but differed in the symmetry of configuration and the level of verbalizability. An intragroup experimental plan was used. Eye movements were recorded in the process of visual search with the SMI HiSpeed 1250 eye tracker. Sample. The total sample of the study consisted of 48 participants: 18 people (10 men, 8 women, average age — 20) — at the stage of assessing the verbalizability of stimuli; 30 people (6 men, 24 women, average age — 20) — at the main stage. Results. None of the factors affected the effectiveness of visual search, it remained at a high level. In the absence of the target stimulus in the matrix, the search for symmetrical targets with verbalizability was completed faster, the search for asymmetric stimuli with low verbalizability was the slowest. Both factors influenced the features of searching eye movements: the search for "simple" (symmetrical and/or highly verbalizable) stimuli was characterized by shorter fixations and wide-amplitude saccades than the search for "complex" targets. ANOVA showed that there is no interaction between the factors of verbalizability and symmetry. Conclusion. The results generally support the hypothesis about the influence of symmetry and verbalizability on the visual search, testifying in favor of their independent influence on the dynamics of search eye movements.

ВОСПРИЯТИЕ СИММЕТРИЧНОСТИ ПРАВИЛЬНО ОРИЕНТИРОВАННОГО И ИНВЕРТИРОВАННОГО ЛИЦА

Background. X e uniqueness of human face perception mechanisms and their variability has become a subject for extensive investigation and wide discussion in the recent decades. While now the concept that human face is perceived as a whole is taken as a fact, the same cannot be said about the structure and methods to measure holistic processing. In the present study the factor of symmetry is investigated as one of the possible aspects of conW gural processing of facial perception. Objective. X e aim of the study was to apply the inversion method to the investigation of how distortion of facial conW guration perception impacts the rating of its symmetry/asymmetry Sample. 54 participants (24 female and 30 male) aged 18 to 68 (mean age 26) took part in the study. Method. An intra-individual experimental design was used. Participants rated asymmetry of normally oriented and inverted face-stimuli on a W ve-point scale. To set the symmetry level, leY eye and/or mouth regions were rotated around their W ducial points, there were three rotation angles for each feature region. Zero asymmetry faces were created by blending halves of normal and mirror images of the sample face-stimulus. X e mean asymmetry subjective ratings were submitted to repeated measures analysis of variance and paired samples t-test. Results. X e study revealed signiW cant diZ erences in the asymmetry ratings of upright and inverted faces: normal upright faces with rotated features were rated as more asymmetric compared to inverted. X us, we may conclude that symmetry perception is aZ ected by inversion. It was also revealed, that the eZ ect of the eye region and the lips region rotation were not equivalent: the higher the level rotation of the eye area was the more signiW cant the diZ erence between the rates of upright and inverted faces was, while rotation of the lips area did not result in higher diZ erence between the rates. Conclusion.X e observed face-inversion eZ ect in the perception of symmetry in facial stimuli suggests that (a)symmetry is a component of holistic (conW gurative) processing of human face perception. At the same time, the contributions of individual features to the overall facial conW guration may diZ er.

Fabrication process development and basic evaluation of eggshell-based column packing material for reversed-phase preparative separation

Purification of basic drugs in reversed-phase mode is often difficult, mainly due to adsorption of positively charged compounds to the silica gel-based stationary phase. Since this adsorption can be suppressed under alkaline condition, columns with alkali-resistance are required. In addition, compounds with acid-sensitive structures are sometimes degraded during separation on silica gel-based columns which exhibit acidity due to their surface structure. We prepared an alkali-resistant reversed-phase packing material, Eggshell-PMAcO based on eggshells modified with an amphiphilic copolymer, poly(maleic acid-alt-1-octadecene) (PMAcO). The height equivalent to a theoretical plate (HETP) of the Eggshell-PMAcO column was improved by surface treatment with ammonium acetate buffer (900 mM, pH = 3.7), which is an inexpensive reagent, and the retention behavior for hydrophobic compounds was compared to a typical ODS column based on silica gel, resulting in sufficient selectivity of the eggshell-based column for hydrophobic compounds, as indicated by the ratio of retention factors of pentylbenzene and butylbenzene (Eggshell-PMAcO column: 1.55, ODS column: 1.65). Column temperature-dependent retention behavior of naphthalene was investigated in the temperature range from 25 °C to 45 °C, followed by the calculation of thermodynamic parameters. There was little difference in the standard molar enthalpy (Eggshell-PMAcO: −19.6 kJ/mol, ODS: −21.7 kJ/mol). The absolute value of the standard free Gibbs energy for the Eggshell-PMAcO column was much smaller than that of the ODS column (Eggshell-PMAcO: −0.284 kJ/mol, ODS: −13.0 kJ/mol), indicating that the Eggshell-PMAcO column had a weaker retention strength for naphthalene than the ODS column mainly due to the large difference in the standard molar entropy (Eggshell-PMAcO: −64.9 J/mol K, ODS column: −29.2 J/mol K). The retention capacities for imipramine under neutral (water/methanol) and alkaline (0.1% triethylamine water/methanol) conditions were 0.2 mg and 5 mg, respectively, based on injection mass-dependent HETP, retention factor and symmetry factor. Finally, the prepared column was applied to the purification of a building block for nucleic acid drugs. This study demonstrated that reversed-phase columns, which can be fabricated from eggshells and an amphiphilic copolymer in an inexpensive and eco-friendly way, have the ability to purify basic compounds and acid-sensitive compounds.

Neotectonics assessment using geomorphic indices: A study from the passive continental margin of India

ABSTRACT The response of landforms to tectonic deformative processes can be effectively understood by using geomorphic indices. The objective of this study is to evaluate the extent of neotectonic activities in the fourth-order sub-basins of a tropical river basin (Kallada River basin) in the Southern Granulite TerrainIndia. The extend of neotectonism was analyzed using geomorphic indices such as asymmetry factor, transverse topographic symmetry factor, hypsometric integral, stream-length gradient index, drainage basin shape index, ratio of valley floor to valley height, and mountain front sinuosity, with values varying from 0.3 to 41.20, 0.12 to 0.54, 0.13 to 0.69, 12.76 to 1036.49, 0.63 to 3.81, 0.05 to 6.04, and from 1.02 to 3.08, respectively. Further, the relative active tectonics index (IRAT) was derived from the geomorphic indices using GIS and the values vary from 1.67 to 3.0. Based on the degree of relative tectonic activity, Kallada River basin was classified into class 1, 2, 3 and 4 corresponding to very high (1.0-1.5), high (1.5-2), moderate (2.0-2.5), and low (IRAT>2.5) values. The spatial distribution of different “IRAT” classes shows a gradational pattern from east to west, suggesting a gradual decrease in the neotectonic activity in the basin.

Naturally Occurring Montmorillonite-Based Polymer Monolith Composites as Stationary Phases for Capillary Liquid and Gas Chromatography

This work is associated with the preparation of capillary chromatographic columns containing inorganic-organic composites comprised of naturally occurring montmorillonite (MMT) clay mineral and polymethacrylate monolithic material. The prepared composites combine the best qualities of both constituents, offering desirable properties for use under the disparate conditions of both GC and HPLC at the same time. The stationary phases were investigated by scanning electron microscopy (SEM), the specific surface area, and thermogravimetric analysis (TGA) and examined in terms of various conditions utilized for GC and HPLC methods. The prepared columns demonstrated an excellent permeability and stability against common chromatographic conditions, such as the eluent type, flow rate, pressure, and temperature. The results confirmed that the addition of small amounts of MMT into the monolith induced significant improvement in the specific surface area, which contributed to the formation of more active sites and enhanced the retention of analytes. The registered column backpressures did not exceed 980 kPa and 16,500 kPa for the prepared GC and HPLC columns, respectively. The prepared columns were subjected to the separation of various interesting compounds possessing different chemistries and polarities, including alkanes, alkylbenzenes, polycyclic aromatic hydrocarbons (PAHs), alcohols, ketones, phenols, some common organic solvents, and isomeric mixtures. Under the optimal conditions, the efficiency of the columns fell between 4900–38,500 plates m−1 for GC and 3400–58,800 plates m−1 for capillary HPLC applications. In all cases, the measured chromatographic resolution was more than 1.38, with excellent an peak symmetry and low tailing factors. In comparison with the most commonly used commercial columns, the polysiloxane open tubular column for GC and silica-based C18 packed column for HPLC, the prepared GC columns demonstrated a faster separation with a higher efficiency, comparable resolution and tailing factors, and lower consumption of carrier gas. Regarding the capillary columns prepared for HPLC, the chromatographic experiments exposed a much lower run time with a comparable efficiency and resolution and drastically lower consumption of mobile phase solvents and samples. The results demonstrate that the MMT-based polymethacrylate monolith composites are applicable as novel and promising separation media for analyzing various mixtures of interest in different fields, such as petrochemical and environmental samples.

Metal dissolution from first principles: Potential-dependent kinetics and charge transfer

Metal dissolution and its inverse process are integral to both corrosion and electrodeposition; however, many mechanistic details regarding the dissolution process are challenging to decipher. These include how ion dissolution kinetics and charge transfer are influenced by the competition between metal and solvent interactions under an electrode potential. In this work, we introduce a computational framework based on density functional theory with grand-canonical treatment of electrons to directly predict the potential energy landscape for metal dissolution at a constant potential. Using aluminum as an example, we demonstrate that dissolution kinetics is governed by competing kinetics between two physical processes associated with metal–metal bond breaking and ion-migration within the electrical double layer, respectively. We identify a kinetic transition between regimes dominated by each of these processes and show that this transition depends on the operating electrode potential, among other key factors. It is further found that kinetics and thermodynamics of these processes can be described with a simple, one-parameter Marcus-theory-type model. Beyond offering new understanding of charge transfer during dissolution, our simulation protocol provides a recipe for directly predicting other important quantities in electrochemical reactions from first principles that are difficult to measure, such as the symmetry factor.

All-orders asymptotics of tensor model observables from symmetries of restricted partitions

The counting of the dimension of the space of polynomial invariants of a complex 3-index tensor as a function of degree n is known in terms of a sum of squares of Kronecker coefficients. For , the formula can be expressed in terms of a sum of symmetry factors of partitions of n denoted , which also counts the number of bipartite ribbon graphs with n edges. We derive the large n all-orders asymptotic formula for making contact with high order results previously obtained numerically. We explain how the different terms in the asymptotics are associated with probability distributions over ribbon graphs. The derivation of the asymptotics relies on the dominance in the sum, of partitions with many parts of length 1. This large n dominance of small parts also leads to conjectured formulae for the asymptotics of invariants for general d-index tensors. The coefficients of powers of in these expansions involve Stirling numbers of the second kind along with restricted partition sums.