Central Section Research Articles

Safety Analysis and Condition Assessment of Corroded Energy Pipelines under Landslide Disasters

Corrosion poses a significant risk to the safety of energy pipelines, while landslide disasters emerge as the primary threat responsible for triggering pipeline failures across mountainous areas. To date, there is limited research focused on the safety of energy pipelines considering the synergistic effect of corrosion and landslides. The present study proposes a finite element (FE)-based model to assess the condition of corroded pipelines under landslides. The effects of corrosion dimensions (length and depth) and location are determined. A novel equation is finally developed to predict the maximum stress and determine the most disadvantageous position for corroded pipelines under various landslide displacements. The results demonstrate that (1) as the landslide progresses, the pipeline’s stress significantly increases; (2) corrosion depth has a more significant impact on the pipeline condition than the corrosion length, and it is positively correlated with the pipe’s stress; (3) the maximum stress exhibits a nonlinear relationship with the landslide-facing position and the corrosion circumferential location; and (4) when the axial position of the corrosion is more than 6.5 m away from the center of the landslide, the location of maximum stress shifts from the corrosion region to the central section of the pipeline within the landslide. This work contributes to helping pipeline owners to understand the applicability of energy pipelines subjected to the combined effects of corrosion and landslides and provides support for future risk assessment efforts in pipeline integrity management.

Using genetic comparisons of populations from Arizona, Mexico, and Texas to investigate fall armyworm migration in the American southwest.

Fall armyworm (FAW) is a global agricultural pest, causing substantial economic losses in corn and many other crops. Complicating efforts to control this pest is its capacity for long distance flights, which has been described in greatest detail for the central and eastern sections of the United States. FAW infestations are also routinely found in agricultural areas in southern Arizona, which lie beyond the western limits of the mapped migratory pathways. Climate suitability analysis found that the affected Arizona locations cannot support permanent FAW populations, indicating that these FAW most likely arise from annual migrations. A better understanding of this migration would provide insights into how large moth populations can move across desert habitats as well as the degree of gene flow occurring between FAW populations across the North American continent. In this study the Arizona populations were genetically characterized and compared to a selection of permanent and migratory FAW from multiple sites in the United States and Mexico. The results are consistent with migratory contributions from permanent populations in the states of Texas (United States) and Sinaloa (Mexico), while also providing evidence of significant barriers to gene flow between populations within Mexico. An unexpected finding was that two genetically distinct FAW subpopulations known as "host strains" have a differential distribution in the southwest that may indicate significant differences in their migration behavior in this region. These findings indicate that the combination of mitochondrial and Z-linked markers have advantages in comparing FAW populations that can complement and extend the findings from other methods.

Bayesian inversion for modelling 3-D density structures in the eastern margin of Bayan Har block and its tectonic implications

SUMMARY Recently, the eastern margin of the Tibetan plateau has experienced three moderate earthquakes. Deep crustal structure is a critical factor for understanding the seismotectonic environment and deformations in this region. Although several multidisciplinary geophysical approaches have been used to develop crustal structure models for this area, substantial inconsistencies still persist in the results due to the intricate structural properties of crust. In this study, we introduce a novel approach to construct a 3-D crustal model with assimilated density structure (MADS) at a resolution of 0.2° × 0.2° × 5 km. This model is built by integrating data from various source, including multisource gravity anomalies and diverse available crustal structure reference models. We use a model-assimilated gravity inversion process with Bayesian parameter optimization. First, we combine the terrestrial gravity profiles data set with published global gravity field models to create a data set rich in reliable high-frequency anomaly information. Secondly, we incorporate three reference models derived from different seismological methods as prior constraints for our model. These models encompass seismic tomography, surface wave dispersion and receiver function data. We optimize the hyper-parameters of these constraints using the Bayesian criterion. The results demonstrate that the MADS not only captures significant changes in the crustal density but also discerns subtle variations in the upper and middle crust, thereby providing detailed insights into the morphologies of major faults. For instance, the central section of the Longmenshan fault is revealed as a high-angle deep thrust feature, while the frontal section of the Longmenshan fault appears as a low-angle mid-deep thrust feature, and the Xianshuihe fault exhibits a vertical deep subduction feature. Additionally, our findings indicate a correlation between the locations of moderate-to-large earthquakes in this region and the high density-gradient zones or asperities with high density within MADS. We believe that the insights into density characteristics offered by the new MADS model can shed light on the study of asperities associated with recent moderate earthquakes and enhance our understanding of deformation in this region.

Associations between endogenous spike cytokinins and grain-number traits in spring wheat genotypes

Genetic variation in grain number has been positively associated with levels of cytokinins in inflorescences in cereals, although studies quantifying endogenous levels in the field are currently lacking. The present study, using a spring wheat association mapping panel (HiBAP II) of 150 lines, quantified associations between spike hormone levels and grain number and associated traits. The HiBAP II panel was grown in the field in NW Mexico under irrigated conditions for one year and a subset of ten genotypes in the glasshouse under well-watered conditions for three years. The spike levels of four cytokinins (trans-zeatin riboside, trans-zeatin, isopentenyladenosine, and isopentenyladenine) were measured by using ultra-high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. In the glasshouse experiments, spike hormone levels were measured at booting and anthesis, and in the field experiment at anthesis. In the glasshouse experiments, cytokinin levels were also measured in the basal, central, and apical spikelets separately in addition to at the whole spike level. The spike cytokinin levels did not differ significantly between the basal, central and apical sections of the spike. or show a spike position × genotype interaction. In the glasshouse experiments, significant genetic variation was detected for the expression of the four cytokinins in spikes at booting. At booting, spike trans-zeatin concentration ranged amongst genotypes from 4.5 to 16.0 ng g−1 FW and was positively correlated with grain number per main shoot (r = 0.77, P < 0.05). In the field at anthesis, the spike levels of each of trans-zeatin, trans-zeatin riboside and isopentenyl adenosine were positively correlated with grains per m2 (r = 0.17–0.19, P < 0.05). Our results indicated that selection for high spike cytokinin levels in wheat germplasm offers scope to raise grain number and yield potential in wheat.

Spatial distribution, ecological risk and origin of soil heavy metals in Laoguanhe watershed of China's South-to-North Water Diversion Middle Route Project

The central section of China's South-to-North Water Diversion Project has been designated as a national water conservation area, and the soil ecological security in its associated watersheds is of great importance. A total of 204 soil samples (0–20 cm depth) were obtained from the Laoguanhe River Basin. The concentrations of seven elements (Cd, Cr, Cu, Ni, Zn, Pb and Hg) were determined using inductively coupled plasma mass spectrometry and atomic fluorescence spectrometry following a near-total acid dissolution. Data analyses (including potential ecological risk, principal component analysis, geostatistical analysis and the positive matrix factorization model) were applied to evaluate the contamination of soil heavy metals and to identify their sources. The research results demonstrated that the mean contents of these seven elements exceeded background values for Henan Province, China, indicating human disturbance. Ecological risk evaluation revealed that Cd was the most frequently detected and the heavy metal causing the most pollution. Principal component analysis indicated that Cr, Ni and Cu stem from natural sources, while Zn and Cd are predominantly influenced by agricultural activities. Additionally, industrial activities and atmospheric deposition were responsible for the excess presence of Pb and Hg. The study suggests taking measures to control Cd sources in agricultural areas, reducing input of heavy metals into the river and providing scientific support for managing water quality.

Surface rupturing earthquakes along the eastern Rhine Graben Boundary Fault near Ettlingen-Oberweier (Germany)

The eastern Rhine Graben Boundary Fault (eastern RGBF) forms the eastern margin of the Upper Rhine Graben (URG), the most seismically active area in the plate interiors of Europe. Despite seismic activity posing a significant threat to the densely populated URG and critical facilities therein, only a few studies have documented the paleoearthquake history and associated seismic hazard, focusing mainly on the western margin. We present the results of the first paleoseismological trenching ever conducted on the central section of the eastern RGBF. Following high-resolution near-surface geophysical studies, we excavated six trenches near Ettlingen-Oberweier (south of Karlsruhe, Germany) on one of its secondary fault strands. The nearly-vertical fault is transtensional left-lateral and splits into several NNW-SSE en échelon branches, forming a negative flower structure. Stratigraphic and structural relationships along with radiocarbon and Optically Stimulated Luminescence dating reveal a minimum of three surface-rupturing paleoearthquakes with a Mw of potentially 6.5 ± 0.5, occurring from old to young, >56 ka (EX), between 54 and 19 ka (EY), and between 15 and 1 ka (EZ). The events are poorly constrained in age due to erosional unconformities. Based on the cumulative vertical separation of 1.2 ± 0.3 m, we calculate an average vertical slip rate of 0.02 ± 0.005 mm/yr. From a horizontally offset alluvial channel, we infer a cumulative left-lateral slip of 5.9 ± 0.7 m and derive an average horizontal slip rate of 0.1 ± 0.01 mm/yr. The average net slip rate is 0.1 ± 0.02 mm/yr for the past 59.5 ± 3.8 ka. This value represents a minimum slip rate for the eastern RGBF, considering slip distribution within the different fault strands of the fault system. Our findings highlight the seismic potential of the eastern RGBF, providing new evidence of the Late Pleistocene and Holocene tectonic activity of its central section.

Assessing the results of work on strengthening the soils of the foundation of lock № 5 of the Volga-Don shipping canal and proposals for stabilizing the chamber position

The results of work to strengthen the soil foundation of the chamber of lock № 5 of the Volga-Don Shipping Canal, carried out in 2016–2017, are analyzed. The need to carry out work to strengthen the soil was caused by an increase in the intensity of sedimentation of the central sections of the lock chamber, which began in 2005. To stabilize the chamber position, the technology of two-component jet grouting is implemented. This technology assumes the formation of several longitudinal soil-cement walls in the soils of the lock chamber base, which would transfer the load from the weight of the chamber to the harder clay soils of the water-resistant layer. However, as a result of the work performed, the precipitation intensity has increased. Engineering-geological, hydrological and geophysical studies conducted in 2018–2020 recorded the absence of formed soil-cement elements in the soils of the chamber base. An analysis of the soil samples characteristics taken from the chamber base has showed that a layer of soils of 10–12 m thickness is composed of loess rocks, below which water-resistant clayey rocks lie. Initially, there were several confined and non-confined aquifers in the soils of the lock base, and the creation of a hydroelectric complex and the formation of a level difference between the upper and lower pools led to the formation of a filtration flow with a significant pressure gradient at the base of the chamber. An analysis of the properties and structure of loess soils has showed their predisposition to subsidence, transition to a floating state and liquefaction with an increase in water content. Under the conditions of weak water-saturated loess soils, the supply of a cement mixture into them under significant pressure did not lead to the formation of soil-cement elements. Thus, in accordance with the current regulatory documents, the technical condition of the gateway is defined as pre-emergency, and the security level is defined as unsatisfactory. Methods for reducing the intensity of the chamber sedimentation such as cutting through the loess layer with piles, physical and chemical strengthening of soils and water protection of the massif at the base of the chamber are considered and evaluated.

Role of Q-heterochromatin and thermal conductivity of the human body in the development of obesity

Introduction and Aim: Obesity, commonly known as a complex multifactorial disease, has emerged as a significant medical and societal issue in recent decades. The objective of this study is to assess if there is a significant impact of Q-heterochromatin (Q-HR) and thermal conductivity (k) in the body on the risk of obesity. Methods: This prospective analytical cohort study included 300 individuals from both genders aged 35.24 4.21 years who do not have oncological, hormonal, or other forms of diseases that predispose to morbid obesity. Results: In obese individuals, the temperature distribution in the peripheral and central parts of the body has a high level of variability relative to the control. In the main group, Q HR has a clear gradient from 0 to 2, and the average numerical parameter is 1.21 0.11, which is more than twice as low as in the control group (2.94 0.14). In obese individuals, the chromatin concentration decreased with increasing temperature gradient (X2 = -16.8; p0.001). Conclusion: The level of Q-HR is considerably lower in obese people compared to the control group. When compared to the control, obese people had a higher k between the central and peripheral sections. The level of Q-HR and k were shown to be inversely correlated.

Parameters of the P300 auditory evoked potential and autonomic heart rate regulation in adolescents residing in different climatic and geographical conditions of Russia

BACKGROUND: The physiological functions and body development take place as the body adapts to the environment. For schoolchildren aged 16-17, their primary focus is on studying, which involves processing and retaining a significant volume of diverse information. The P300 auditory evoked potential reflects the neurophysiological aspects of cognitive functions such as attention and memory. This assessment is particularly relevant when considering the autonomic heart rate regulation in young individuals residing in the northern and southern regions of Russia.&#x0D; AIM: The objective of this study was to assess the auditory evoked potential components, namely P300 and N2, along with heart rate variability parameters in a group of healthy young Russian adolescents living in different climatic and geographical conditions.&#x0D; MATERIAL AND METHODS: The study sample consisted of 156 individuals aged 1617 years permanently residing in Arkhangelsk, Nadym and Simferopol. The assessment of the autonomic nervous system was carried out according to the parameters of heart rate variability on the agro-industrial complex Varikard. Registration of P300 and N2 components was carried out on the Neuron-Spectrum-4/VPM electroencephalograph (Neurosoft, Russia), using the oddball paradigm.&#x0D; RESULTS: The predominance of sympathetic nervous system activity in the regulation of heart rate and the lengthening of the N2 latency was revealed in adolescents in Nadym. In residents of Arkhangelsk and Simferopol, there were no differences in the parameters of heart rate variability and components of the auditory evoked potential of P300. Interhemispheric asymmetry of N2 latency was observed in young people of Arkhangelsk, where the time was shorter in the central (C4, p=0.04) and right anterior temporal (F8, p=0.01) sections.&#x0D; CONCLUSIONS: The imbalance in the autonomic nervous system towards the predominance of sympathetic influences in the heart rate regulation is reflected in slower recognition and differentiation of the sound signal.

DEM Simulation of the Single-Acting Pressed and Double-Acting Pressed Nd–Fe–B Compacts

The orientation distribution of Nd-Fe-B compacts under single-acting pressing (SAP) and double-acting pressing (DAP) was simulated by the discrete element method (DEM). The results showed that for both SAP and DAP compacts, the particles in the central section had a higher alignment degree than those near the die wall in the direction parallel to the applied magnetic field, due to the relative motion between different sections within the compacts. Moreover, the sections near the punches had more poorly aligned particles because they underwent a longer movement distance and a larger compressive force. Meanwhile, the DAP compact had a higher alignment degree than the SAP compact, owing to the smaller differences in movement distance among various sections in the DAP compact during the pressing process. Furthermore, the orientation direction varied in the direction parallel to the applied magnetic field, and exhibited a mirror symmetry in the direction parallel to the applied compressive force for the DAP compact. The results provided an insight to optimize the magnetic pressing process and improve the quality of Nd-Fe-B compacts.

The Evaluation of WaveSAX Power Generation to Support Port Energy Self-Sufficiency

Remarkable advancements have been made in wave energy converters, notably the innovative WaveSAX technology—an oscillating water column system conceptually designed for coastal structures. Proven effective in existing installations, particularly at Civitavecchia Port, Italy, where the WaveSAX-1 prototype was tested in 2018 and the WaveSAX-2 was updated in 2021. The device’s power generation capacity was evaluated using a Simulating WAves Nearshore (SWAN) model that simulated 30 years of wave conditions. Validation with radar and Acoustic Doppler Profiler instruments showed excellent performance in wave height simulation. Results revealed higher wave power generation near the harbor breakwater, surpassing offshore levels, especially in central and northern sections. WaveSAX-2, featuring an improved Wells turbine, demonstrated a remarkable 37% increase in average efficiency compared to WaveSAX-1. If a linear WaveSAX array were installed, it could produce 4 GWh annually, satisfying 20% of the port’s energy needs and reducing around 2800 tCO2e/year. Doubling arrays and incorporating triangular modules could significantly enhance sustainability for port operations, offering a promising path toward self-sufficiency and environmental responsibility.

FORMING THE READINESS OF THE FUTURE SPECIALIST TO USE INFORMATION TECHNOLOGIES

The article exposes the problematic of creating the readiness of the future individual to use information technologies. Computers open up new ways in the progress of intellectual assistances and the facility to explain professional tasks when training future specialists in higher education. The main directions of using information technologies are highlighted. The effectiveness of computer use at various stages of the pedagogical process is determined. The practice of computer technologies by students in the progression of education the basics of science pays to growing the success of the educational process in the field of learning the ability to independently accumulate and present knowledge. The informational component of a specialist’s readiness is defined, which is today an central section of defining the value of his training.The process of forming a new information environment of society creates unique opportunities for human progress, for the real answer of several professional, economic, social and everyday difficulties. The socio-economic change of the nation depends on the presence of a modern information sphere of society. The information sector primarily depends on qualified personnel, which, in turn, crucially depends on the education system in the country. One of the main tasks facing the education system is the task of forming the basics of the information values of the future expert.

Analysis of vortex combustion flow in a chamber of guide ring coupling with swirl flow

To investigate the impact of different vortex structure on the combustion stability in a chamber, this paper evaluates the performance of a vortex combustion chamber coupled with a swirler and a guide ring. The simulated cases include different guide ring angles of 95°, 105°, 115°, 125° and 135°, in addition to a control case without coupling the guide ring. The distributions of velocity, vorticity, temperature, outlet temperature distribution factor ( OTDF), reaction rate, turbulent kinetic energy ( k), synergy angle ( β), and NO emission are numerically analyzed. Results show that the coupling of the swirler and guide ring changes the vortex structure and significantly influences the chamber performance. The increase of the guide ring angles ( α) enhances the interaction between the swirl flow and the direct jet, which intensifies heat and mass transfer, as well as turbulence. The application of the guide ring induces external entrainment of the jet, leading to the formation of a large central recirculation zone compared to that without a guide ring. With increasing the α from 95° to 135°, both average outlet velocity and tangential velocity ( Vt) at the coaxial line position decrease, while the flame length decreases by 286 mm. And the OTDF variation among all cases is less than 0.065. The β of the central section decreases from 76.18° to 70.17°. Furthermore, combustion chamber without the guide ring exhibits higher temperature and OTDF.

Characterization and scanning electron microscopy of Malassezia species isolated from central line tips of neonates on total parenteral nutrition

Background: Aim of this study was to demonstrate colonization by Malassezia species in the central lines of very low birth weight newborns on total parental nutrition (TPN). We also aimed to perform scanning electron microscopy (SEM) of central line tip cut sections to document the quality of the biofilm, cell structure, micro-colony characteristics, and the presence of extracellular matrix. Methods: We collected central line tips of very low birth weight newborns (&lt;1.5 kg) over a one-year period. We included a total of 63 samples, which were cultured on slants along with controls purchased from CBS Netherlands. We incubated the cultures at 32°C and observed them every two days for three weeks. Once growth occurred, we phenotypically identified the cultures and observed the central line tip cut sections with SEM. Results: Among the 63 central line tips, two (3.1%) were colonized by Malassezia. We observed a visible biofilm on the tips. We confirmed the phenotypic identification of the isolates as M. furfur and M. restricta by gene sequencing. Conclusions: Our study revealed Malassezia colonization in the central line used for total parenteral nutrition. Hence, it is important to have a high index of suspicion towards Malassezia catheter-related blood stream infection in newborns on TPN with a clinical picture of fever (in spite of antibiotic therapy), leukocytosis, thrombocytopenia with cardiac disease, and pulmonary infiltrates. The outbreak potential of Malassezia warrants preventive steps, and early identification and treatment.

Crustal and uppermost mantle structure near the Gloria Fault, North Atlantic, from ocean bottom seismometer surface wave observations

SUMMARY In this work, we present both 1-D and 3-D shear wave velocity (Vs) models of the oceanic crust and uppermost mantle below the Deep OCean Test ARray area, located ∼ 70 km north of the central section of the Gloria Fault, in the eastern North-Atlantic Ocean. The velocity models are inferred from the dispersion of surface waves recorded on ocean bottom seismometers. Dispersion measurements are obtained from the analysis of ambient seismic noise at short periods (&amp;lt; 14 s) and teleseismic surface waves at long periods (&amp;gt; 14 s) using the two-station method. The 1-D Vs model is inferred from the joint inversion of Rayleigh wave phase velocities and Love wave group and phase velocities. The 3-D tomographic model is obtained by inversion of 2-D Love wave group velocity maps as a function of depth, further constrained by the average of Love wave phase velocities obtained from ambient noise (4–9 s) and the average Rayleigh and Love wave phase velocities calculated from teleseismic data (14–44 s). The 1-D Vs model shows a sediment layer with a low velocity of 1.05 km s−1, similar to previous studies in the region. Below the sediments, we find an oceanic crust with velocities ranging from 3.3 to 4.5 km s−1. The model reaches an unusually high velocity of 4.9 km s−1 in a 20 km thick layer at depths between 16 and 36 km. We interpret this fast velocity layer as indicative of the presence of harzburgite, a residue of enhanced melting that might have been formed by the proximity between the Mid-Atlantic Ridge and the Azores mantle plume. At greater depths the velocity decreases, forming a low-velocity zone that reaches a minimum at ∼ 70 km depth, which we interpret as the maximum depth for the lithosphere–asthenosphere boundary. The 3-D model shows a structure that is mostly horizontally layered, with Vs isocontours at 3.5–4.5 km s−1 highlighting oscillations of the crustal structure with wavelengths of ∼25–30 km. These oscillations may be due to changes in the rate of mantle upwelling and magma supply rate.

The analysis of the destabilizing motion of a hyperbolic cooling tower during demolition blasting

The destabilizing motion characteristics of the hyperbolic cooling tower in demolition blasting are thoroughly investigated through the establishment of a numerical simulation calculation model, leading to the following conclusions regarding its destabilizing motion. The tensile-compression elastic-plastic model, which possesses the characteristics of parameter modification function and independence from unit size, can more effectively capture the mechanical properties of concrete materials and find better application in the simulation and calculation research of reinforced concrete structures. The self-oscillation frequency check and collapse morphological analysis are employed to validate the accuracy of the simulation calculation model for hyperbolic cooling towers, as well as to assess the rationality of parameters in the tensile-compression elastic-plastic model. The collapse of a cooling tower induces flexural deformation in the lateral wall, tensile disturbance in the upper and middle sections of the cylinder, and compressive disturbance in the vertical cross-section. The cylinder body has incurred damage as a result of the tower wall’s front end striking the ground at the directional window position on the front side of the throat, leading to a significant extrusion deformation issue. The buckling deformation in the central and lower sections of the rear wall propagated towards the back side of the tower wall upon reaching the ground, ultimately resulting in an “inverted V-shaped” damage along the buckling deformation line. The research findings hold significant relevance for future endeavors.

Simulation Study on Stress-Strain and Deformation of Separator Under Battery Temperature Field

Understanding the thermal stress, thermal strain, and deformation law of separators under a battery temperature field significantly improves battery safety. This article analyzes the temperature field distribution characteristics of an NCM523 soft pack lithium-ion battery under different discharge rates, and the thermal stress, strain, and deformation laws of the separator in the battery temperature field are evaluated through numerical simulation. The results show that the tabs have the lowest temperature in the battery, and the highest temperature is observed in the middle lower part of the center section of the cell. At a constant external temperature of 300 K and a discharge rate of 0.5 C, the maximum temperature of the battery at the end of discharge is 302.402 K. As the discharge rate increases, the maximum temperature of the battery gradually increases. The distribution of the thermal stress and thermal strain of the separator is related to the distribution of the battery temperature field; where the battery temperature is high, the thermal stress and thermal strain of the separator are large. The largest deformation of the separator occurs in the corner region. Moreover, with increasing discharge rate, the expansion of the separator increases.

Polymetamorphism during the Grenvillian Orogeny in SE Ontario: Results from trace element mapping, in situ geochronology, and diffusion geospeedometry

AbstractThe Flinton Group is a metasedimentary succession of the Grenville Province in SE Ontario, potentially allowing insight into the tectono‐thermal evolution of continental crust during the Mesoproterozoic. At its Green Bay locality, Flinton Group metapelites of the staurolite zone contain abundant, post‐kinematic garnet porphyroblasts. Whereas the larger garnet crystals are typically impinged, smaller crystals are isolated from each other, occasionally exhibiting elongated shapes with apparently trigonal morphology. Central sections of the garnet population of a representative sample reveal that garnet is composed of different compositional and microstructural domains. In the largest crystals of the population, garnet contains rectangular to rhombic domains, marked by sharp increases in the concentrations of Nb, V, Ti, and Cr. These domains are associated with irregularly shaped patches, characterized by spatially heterogenous enrichments of Ca and LREE, and depletions in the contents of P, Y, MREE, and HREE, accompanied by increased densities of comparatively coarse‐grained quartz inclusions hosting apatite. Microstructural relationships indicate that these domains correspond to portions of garnet that pseudomorphed biotite, with the enrichments of Nb, V, Ti, and Cr outlining the original biotite shapes. The compositional patterns formed by Ca, P, Y, and REE indicate that apatite participated in the grain‐fluid interactions that operated during the metasomatic replacement of biotite by garnet. The statistical analyses of the garnet number and size distributions confirm that garnet initially nucleated on biotite, controlled by the kinetics of attachment and detachment processes at the garnet/biotite interface, resulting in the typical impingement habit. In situ Lu–Hf garnet geochronology applied to garnet that did not pseudomorph biotite, and hence is enriched in HREE, points to a first metamorphic event at c. 1080 31 Ma. Subsequent pseudomorphism of staurolite by white mica in a Al2O3‐ and FeO‐mobile system resulted in the concomitant crystallization of a new garnet generation, forming overgrowths on the first garnet generation and nuclei in the fine‐grained matrix. Garnet that nucleated during this event grew to isolated and elongated crystals with apparently trigonal morphology, aligned in a direction c. perpendicular to the rock matrix foliation. The open‐system behaviour during this event limits the use of whole‐rock‐based geochronological and thermobarometrical applications. However, previously published in situ U–Pb ages of monazite included in the rims of the garnet crystals and in the rock matrix indicate that this event took place at c. 976 4 Ma, likely associated with a period of increased hydrothermal activity late in the metamorphic history of the Grenvillian Orogeny. Diffusion geospeedometry calculations indicate that garnet growth during this hydrothermal event lasted for less than 6 Myr.

Coseismic Kinematics of the 2023 Kahramanmaras, Turkey Earthquake Sequence From InSAR and Optical Data

AbstractWe derive the ALOS‐2 coseismic interferograms, pixel‐offsets and Sentinel‐2 sub‐pixel offsets of the 2023 Mw7.8 and Mw7.7 Kahramanmaras, Turkey earthquake sequence. Offset maps show that the sequence ruptured ∼300 km along the East Anatolian Fault (EAF) and ∼180 km along the secondary Cardak and Dogansehir faults. We infer the coseismic slip distribution and interseismic fault motion by inverting the co‐ and inter‐seismic observations. Inversion results show that the coseismic slip (∼8.0 m) and interseismic strike‐slip rate (∼4.6 mm/yr) on the main rupture of the Mw7.8 event are basically consistent with the ∼8.4 m and ∼3.9 mm/yr of the Mw7.7 event. Most coseismic slips of the Mw7.8 and Mw7.7 events occur within 10 and 12 km at depth, respectively, in keeping with the interseismic locking depth of 10.4 ± 3.3 km and 11.1 ± 3.1 km. This implies that the coseismic rupture kinematics correlate with the interseismic strain accumulation. Moreover, static stress changes show that the Mw7.7 event is likely promoted by ∼2 bar stress increase from the Mw7.8 event on the central section of its main rupture.

Theoretical derivation of hydraulic geometry equations for a gravel bed river channel

The geomorphic relations of hydraulic geometry at-a-station and downstream, expressed as power laws, are derived for a straight, single thread, gravel river channel. The cross-section has a plane central bed, narrow or wide, flanked by curved sides or banks. The analysis employs mechanistic formulae for fixed and mobile bed flow resistance, downchannel bedslope, bedload transport and the novel introduction of bedload ratings all expressed as power laws. Steady uniform flow and equilibrium bedload transport conditions are assumed to occur above the central section. Water discharge and sediment size are assumed to be the only known variables. Exponents of the relations of hydraulic geometry are fixed and are consistent with reported theoretical estimates and field measurements. Coefficients are also explicitly derived and are consistent with field measurements and vary owing to the presence of independent variables in their definition. Here aspect ratio has the major influence. The derived equations can provide coarse estimates for the design of canal and river control works. Conditional separate relations between both width and depth, and bed material size or bed slope are also determined for the occurrence of at-many-stations hydraulic geometry. To improve generality, future work should consider the hydraulic geometry of straight gravel channels with bedload transport, but having an irregular cross-section.