External Zone Research Articles

Evolution of the Júcar-Cabriel fluvial system on the Mediterranean watershed of the Iberian Peninsula (Valencia, eastern Spain)

This study presents the characterization and chronology of the Quaternary terrace sequence developed in the confluence zone of the Júcar and Cabriel river valleys. The study area covers a radius of 10 km from the confluence of the two valleys near the locality of Cofrentes (Valencia). It is located in the northern zone of the Ayora-Cofrentes Graben in the northeastern sector of the External Prebetic Zone adjacent to southern Iberian Chain. This N-S graben is an inherited tectonic feature with an axial salt wall subject to different periods of fluvial dissection and refilling since at least the end of the Messinian Salinity Crisis (MSC). Regional isostatic uplift and local uplift and subsidence processes related to salt flow and dissolution during the Quaternary period, favored by fluvial entrenchment and terrace development. The terrace system and the previous pre-incision erosional and depositional surfaces are analyzed from a geomorphological point of view. The terrace system only develops within the soft Mio-Pliocene sedimentary fill of the graben, whilst upstream and downstream this zone the studied valleys develop important gorges (canyons) carved in the Cretaceous tablelands (Caroch Massif) and Mio-Pliocene deposits (Llanura Manchega). The geochronological control is established from 20 numerical ages obtained by different dating methods, such us Electron Spin Resonance (ESR), Optically Stimulated Luminescence (OSL) in detrital sequences and Th/U series in calcareous tufa deposits. Additionally, four K/Ar dates available for volcanic materials disrupting the upper and oldest terrace have been considered. A total of 14 terrace levels were identified between +130–135 m (T1) and +3–4 m (T14) of relative height above the river thalwegs. The T1 has an approximate age of c. 1.6–2.0 M.a. as indicate the age of the volcanic materials from the Agras Volcano intruded in the terrace, marking the onset of Quaternary fluvial dissection in the zone. The obtained geochronological data indicate that the Lower-Middle Pleistocene boundary is slightly above T6 (+60–65 m), which has an ESR age of 577 ± 43 ka. This terrace also documents the onset of the most important period of rise of the salt within the graben interfering drainage development. The geochronological data indicate the occurrence of a second eruptive event during the second half of the Middle Pleistocene related to the terraces T7 (+50 m) and T8 (+35–40 m), updating the volcanic activity in the zone. The beginning of the Upper Pleistocene is recorded by the top sequences of the T9 terrace (+25–30 m) where numerous OSL and Th/U data have been obtained with ages between ca. 105 and 81 ka (MIS 5). However, these young terraces (T8 to T13) are thickened (8–10 m) recording Middle Pleistocene sediments in their basal sequences with ages between ca. 193 and 137 ka (MIS 6). The study provides important data on valley evolution under the interference of volcanic activity, salt –related deformation (diapirism, solution subsidence) and fluvial incision fostered by the rise of the axial diapir (salt wall) protruding the graben since at least the Brunhes-Matuyama boundary. The analyzed fluvial evolution documents interesting cases of river capture, drainage antecedence and tectonic adaptation of the drainage throughout the Quaternary Period. The paper also poses interesting geochronological data on the long-term Quaternary evolution of Mediterranean valleys in the Iberian Peninsula, poorly explored to the date.

Lipid Content Distribution and its Clinical Implication in Patients with Acute Myocardial Infarction-Plaque Erosion: Results from the Prospective OCTAMI Study.

Plaque erosion (PE) is one of the main plaque phenotypes of acute coronary syndrome (ACS). However, the underlying plaque component and distribution have not been systematically analysed. This study aims to investigate the distribution of lipid and calcium content in culprit lesions assessed by optical coherence tomography (OCT) in patients with PE and explore its relationship with prognosis in a cohort of ST segment elevation myocardial infarction (STEMI) patients. A prospective cohort of 576 patients with STEMI was enrolled in our study. After exclusion, 152 PE patients with clear underlying plaque components were ultimately analysed. The culprit lesion was divided into the border zone, external erosion zone and erosion site in the longitudinal view. Each pullback of the culprit lesions was assessed by 3 independent investigators frame-by-frame, and the quantity and distribution of lipid and calcium components were recorded. Of the 152 PE patients, lipid and calcium contents were more likely to exist in the external erosion zone than in the other regions. In particular, a high level of lipid content proximal to the erosion site was significantly associated with plaque vulnerability and a higher incidence of MACEs. This study revealed that high level of lipid content in the proximal external erosion zone was related to high-risk plaque characteristics and poor prognosis, which provided a novel method for risk stratification and precise management in patients with plaque erosion.

Mathematical model of the hydrocarbon displacement process by water in zonally heterogeneous deformable reservoirs

The problem of displacing hydrocarbon systems injected into the reservoir by water in zonally heterogeneous collectors is considered. In this case, the reservoir of circular shape, developed by a single central well, is assumed to consist of two zones with different reservoir and rheological properties. The solution to the problem is obtained, taking into account the incomplete displacement, compressibility of water, and PVT properties of the hydrocarbon system—phase transformation, mass exchange between phases of the hydrocarbon system. Based on the binary representation of the complex hydrocarbon system, a solution to the considered problem is obtained, and an algorithm for calculating the main indicators of the hydrocarbon displacement process to the well is proposed. This algorithm accounts for the fact that the reservoir has different reservoir and rheological characteristics in the near-wellbore region (internal zone) and the distant part of the reservoir (i.e., in the external zone). Keywords: Displacement; Gas-condensate mixture; Volatile oil; Heterogeneous reservoir; Water flooding; Binary model; Unsteady-state flow.

Current Review of the Function and Regulation of Tuberoinfundibular Dopamine Neurons.

Tuberoinfundibular dopamine (TIDA) neurons have cell bodies located in the arcuate nucleus of the mediobasal hypothalamus. They project to the external zone of the median eminence, and the dopamine (DA) released there is carried by the hypophysial portal vasculature to the anterior pituitary. The DA then activates D2 receptors to inhibit prolactin (PRL) secretion from lactotrophs. The TIDA neuronal population is the principal regulatory factor controlling PRL secretion. The neuroendocrine role subserved by TIDA neurons sets them apart from other dopaminergic populations like the nigrostriatal and mesolimbic DA neurons. TIDA neurons exhibit intrinsic oscillatory fluctuations in their membrane potential that give rise to phasic firing and bursting activity. TIDA neuronal activity is sexually differentiated and modulated by gonadal hormones and PRL, as well as an array of small molecule and peptide neurotransmitters. This review covers these characteristics.

Effect of vane angle on turbulence-chemistry interactions, temperature, flow field, burnout, and NOx emissions in swirling flames fueled by semicoke mixtures.

To enhance the combustion efficiency and reduce NOx emissions in large-scale semicoke and bituminous coal blends, an extensive numerical study was conducted. The focus of this study was to optimize the quaternary air vane angle (αv) through detailed analysis of the temperature and flow fields, turbulence-chemistry interactions, char burnout, and NOx formation in a carefully scaled 1:5 dual-swirl burner. The results showed that with increasing αv, the high-temperature flame region was narrowed and the peak temperature was reduced along with the broadened inner recirculation zone and the shrunken external recirculation zone due to better pulverized fuel-oxidant blending and reinforced convective heat transfer. The peak turbulent Damköhler number Dat evidently increased from 197.5 to 496 with increasing αv, which implied a strengthened homogeneous combustion. Additionally, the corresponding mixing time scales increased while the chemical kinetics time scales decreased, which denoted that an intense diffusing flame was generated with a strong turbulent intensity. The peak heterogeneous Damköhler number Das-O2 showed a reduction from 2.54 to 2.27, while the peak values of Das-CO2 and Das-H2O decreased from 0.1 to 0.077 and from 0.02 to 0.015, respectively. The char-O2 reaction was controlled by diffusion/kinetics; both char-CO2 and char-H2O reactions were determined by kinetics, and all gas‒solid reactions showed a kinetically controlled regime. With increasing αv, the enlarged inner recirculation region increased the residence time, and a higher dilution level lessened the peak temperature, which led to reductions in fuel-NOx and the thermal-NOx. The αv range of 30-45° (or swirl number Sn = 0.55-0.95) was suggested by taking the high burnout and low-NOx formation into account.

Philippine mangroves: species composition, characteristics, diversity, and present status

Through the years mangrove areas in the Philippines continued to decline due to human activities. This paper aims to present the status of the Philippine mangroves based on species composition, diversity, and mangrove forest area through manuals, books, and other local and international online resources. Results showed that there were 35 species of mangroves described in terms of their external features, substrate, and zone preference. Bohol had the most diverse mangrove ecosystem with 26–34 species. The most prevalent species were Avicennia, Sonneratia, and Rhizophora that grew in muddy substrates. Among the provinces, 18.52% had mangrove areas recognized as protected areas. Mangrove decline is attributed to the increase of brackish water culture ponds and the greatest decline occurred when shrimp culture boomed in the 1980s. Other causes are over exploitation, weak law enforcement, lack of manpower and resources, corruption, and poor management of mangrove areas and brackish water ponds. Along with this is the loss of flood control and coastal protection indicating increased susceptibility to climate change. Thus, reforestation and reversion of abandoned brackish water ponds are needed. Reforestation must ensure the suitability of mangrove species to the physical characteristics of the environment. Also, the government must actively spearhead the sustainable use of mangrove ecosystems.

The Closed Resolver Project: Measuring the Deployment of Inbound Source Address Validation

Ingress filtering, commonly referred to as Source Address Validation (SAV), is a practice aimed at discarding packets with spoofed source IP addresses at the network periphery. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Outbound</i> SAV, i.e., dropping traffic with spoofed source IP addresses as it leaves its source network, has received widespread attention in operational and research communities. It is one of the most effective ways to prevent Reflection-based Distributed Denial-of-Service (DDoS) attacks. Contrariwise, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">inbound</i> SAV, i.e., dropping incoming spoofed traffic at the destination network edge, has received less attention, even though it provides protection for the deploying network. In this paper, we present the results of the Closed Resolver Project, our initiative aimed at finding networks without inbound SAV and raising awareness of the issue. We perform the first Internet-wide active measurement study to enumerate networks that enforce (or not) inbound SAV. We reach open and closed Domain Name System (DNS) resolvers in tested networks and determine whether they resolve requests with spoofed source IP addresses. Our method provides unprecedented insight into <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">inbound</i> SAV deployment by network operators, revealing 49% IPv4 and 26% IPv6 Autonomous Systems (AS) that suffer from a consistent or partial absence of inbound filtering. By identifying dual-stack DNS resolvers and ASes, we further show that inbound filtering is generally deployed consistently across IPv4 and IPv6. Finally, the lack of inbound SAV exposes 2.5M IPv4 and 100K IPv6 purportedly closed DNS resolvers to many types of external attacks, including NXNSAttack, zone poisoning, or zero-day vulnerabilities in DNS software.

Migration behavior of water molecules and chloride ions at the nanopore scale based on molecular properties under temperature effect

The durability of cement-based materials is closely related to the transmission characteristics of water and chloride ions in the pores of calcium silicate hydrate (C-S-H) gel, especially in the climate conditions with significant temperature difference. The local structure and transport process of water molecules and chloride ions in gel pores are affected by interfacial effects. The unsaturated transport model of sodium chloride solution in C-S-H gel pores is established on the molecular scale, under different temperature and pore size conditions. Divide the regions in the C-S-H gel pore model into internal adsorption zone, external adsorption zone, and free zone. Taking into account the intrinsic mechanisms and molecular properties of water molecules and ions during transport in the C-S-H gel pores, the local structures and dynamic properties of water molecules and ions in the gel pores are quantitatively described. The electrical double layer and the double-layer water film overlap in the 1.5 nm gel pore, the water molecule and the chloride ion are closely arranged. Thus the diffusion coefficient is far lower than others, and is rarely affected by temperature. Considering the changes in the molecule properties of water and ion in different zones in molecular simulation results, a theoretical model of nanopore water and ion migration was established, revealing the migration behavior of water and ions. The results indicate that the steady-state diffusion fluxes of water and chloride ions are positively correlated with the effects of temperature and pore size, and the increasing amplitude of their diffusion fluxes is characterised by a similar phenomenon with that. This research provides a theoretical basis for the mechanism and durability of cement-based materials corroded by water and chloride ions in marine environments.

Impact of Swirling Flow on the Overall Cooling Effectiveness and TBCs Insulation Characteristics of Turbine Vane

Modern gas turbines find extensive applications in aero engines, power generation, marine, and various other industries. Most numerical studies concentrate on turbine aero-thermal performance under different external conditions with vane or coupon; there are a few published results on combustor-turbine interactions. This study reveals the cooling performance of the first stage with or without coatings to provide a reference for high-performance combustors and turbine-integrated design. The results of the study show that (1) The velocity and temperature distribution inside the combustion chamber are obviously affected by the swirling flow. A central recirculation zone is formed near the central axis, and two external recirculation zones are formed between the inlet section of the combustion chamber and the fluid reattachment point. (2) Inside the combustion chamber, the flame temperature in the central recirculation zone is relatively high, and the range of the high-temperature zone expands with the increase of axial distance. Increasing the swirl number decreases the peak temperature level in the combustion chamber. (3) Under the influence of swirl number, the greater the swirl number, the greater the cooling effectiveness of most areas on the vane surface. (4) In regions where there is a decrease in local heat flux, positive values are evident. This suggests that the application of a coating in these areas results in a reduction of heat transfer from the vane to the mainstream. (5) When comparing the coated vane to the uncoated vane, the cooling effectiveness across the entire surface is notably enhanced, with a particularly significant improvement observed on the vane’s suction side. With the increase of Cax, the difference in cooling effectiveness increment under different swirl numbers also increases.

Evolution from Carbonate Platform to Pelagic Environments in the South Iberian Paleomargin (Pliensbachian–Early Toarcian, Early Jurassic): Carbonate Features and Isotope Geochemistry

This paper studies ten Subbetic (Betic External Zones) stratigraphic sections spanning the Pliensbachian–early Toarcian time interval. Eight lithofacies were distinguished: crinoidal limestones, peloidal limestones, breccias, cherty limestones, nodular limestones, hardground surfaces and condensed levels, marls and marly limestone alternance, and dark marls. The biostratigraphy matches data from ammonite and calcareous nannofossil zonations. In addition, we analyzed C and O isotopes from bulk samples from three of the studied sections in which the lower Toarcian sedimentation crops out. The demise of the Lower Jurassic shallow platform developed in the South Iberian Paleomargin was a complex process driven by rifting, which led to tilted blocks giving way to different sedimentary environments. The tectonic stages occurred in the Sinemurian–Pliensbachian transition (R1), toward the lower part of the Ibex Zone (FO of the Biscutum grande, R2), in the Ibex–Davoei zones boundary (FO of Lotharingius barozii, R3), in the lower–upper Pliensbachian (R4), and in the lower boundary of the NJT4d nannofossil Subzone (R5) (Lavinianum Zone, upper Pliensbachian). After this last phase, sedimentation became pelagic in origin throughout the basin, represented by the sections studied. However, the isotope data show no clear record of the different C-isotopic events, though the Davoei–Margaritatus Event, the late Pliensbachian Event, and the Pliensbachian–Toarcian Boundary Event (PTBE) could be cautiously identified. These geochemical features are explained by the convergence of marine currents from Panthalassa (through the Hispanic Corridor) and Tethys.

Factors Related to Limb Occlusion After Endovascular Abdominal Aortic Aneurysm Repair (EVAR)

Limb occlusion is a potentially serious consequence of endovascular abdominal aortic aneurysm (EVAR). This case-control study identifies factors that predispose to limb occlusion. A consecutive series of patients from two centres undergoing EVAR over an eleven-year period 2007- 2017 were identified retrospectively. Patient records were interrogated allowing collations of demographics, intra- and peri-operative data and surveillance data. The pre-operative computed tomography (CT) angiogram was analysed to determine EVAR relevant anatomical data. The primary outcome was occlusion of the iliac limb of the implanted EVAR. Raw data is presented as percentages, with comparative data analysed using Mann-Whitney U and binomial logistic regression. A total of 787 patients (702 males; median age 78 years, range 53-94 years old) were analysed. Fifty patients reached the primary outcome, resulting in an overall limb occlusion rate of 6.35%. Factors predictive of limb occlusion were oversizing by >10% native vessel diameter, with oversizing of >20% in 50% of those that occluded. External iliac artery landing zone (12/50 limb occlusions) 24% and post-operative kinking (5/50 limb occlusions) 10% were also more common in those that occluded. 50 randomly selected controls with similar baseline characteristics were studied. Oversizing of the iliac endograft was found to be significantly greater in the limb occlusion group compared to the controls (p <0.001) which remained significant on regression analysis. There was no correlation with iliac tortuosity. The Cook stent graft had a 9% limb occlusion rate across sites. Medtronic and Vascutek endografts had 2.4% and 2.5% limb occlusion rates respectively. Oversizing of iliac limbs by >20% could be a contributing factor to limb occlusion after EVAR and judicious oversizing should be used.

Characterization and Geological Meaning of the Crystalline Basement Occurrence in the Unaí Region, Minas Gerais State (Central Brasilia Belt)

Granitoid rocks petrographically and compositionally characterized as tonalite, monzonite granodiorite and granite were observed in restricted areas in the central portion of the external zone of the Brasilia Belt. These outcrops of peraluminous rocks were interpreted as the sialic basement of the region, associated with paleogeographic highs prior to the deposition of the Proterozoic sedimentary cover. U-Pb zircon age of 2.14 Ga and geochemical analysis are compatible with other Paleoproterozoic bedrock areas observed mainly in the north Brasilia Belt. The existence of a basement bulkhead conditioned the Neoproterozoic deformation, causing the inflection of regional structures from NNW to N60-70W and over again to the NNW regional trend. The absence of contact metamorphism along the adjacent supracrustal rocks, regional foliation attitude that is different from that observed in the granitoids (tonalite, granotiorite, monzonite and granite) and the older age, show that these rocks represent basement windows and not younger intrusive bodies, as previously interpreted. The rocks studied in this research are correlated to the Aurumina Suite, which represents the main basement rock set in the North Brasília Belt.

The scale-free theory of stellar convection

Context. A new, self-consistent, scale-free theory of stellar convection was recently developed (SFCT) in which velocities, dimensions, and energy fluxes carried by the convective elements are defined in a rest frame co-moving with the convective element itself. As the dynamics of the problem is formulated in a different framework with respect to the mixing length theory (MLT), the SFCT equations are sufficient to determine all the properties of stellar convection in accordance with the physics of the environment alone, with no need for the mixing length parameter (MLP). Subsequently, the SFCT was improved by introducing suitable boundary conditions at the surface of the external convective zones of the stars, and the first stellar models and evolutionary tracks on the Hertzsprung–Russell diagram were calculated. Aims. The SFCT received alternatively positive and negative attention that spurred us to reconsider the whole problem. In this work, we aim to re-examine the physical foundations and results of the SFCT, elucidate some misconceptions on its physical foundations, reply to reported criticisms, and present some recent improvements to the SFCT. Methods. The analysis was done using the same formalism of the previous studies, but novel arguments and demonstrations are added to better justify the controversial points, in particular the relaxation of instantaneous hydrostatic equilibrium between a convective element and the surrounding medium. Results. The main results include (i) a novel detailed discussion of the boundary conditions to ensure that the temperature gradients in the outermost regions of a star are adequate for analyses of stability or instability in asteroseismology; (ii) a quantitative comparison with the MLT; and, finally, (iii) the recovery of the MLT as a particular case of the SFCT, but also in this case with no need for the MLP. Conclusions. In conclusion, the SFCT is a step forward with respect to the classical MLT.

Control of the flame and flow characteristics of a non-premixed bluff body burner using dielectric barrier discharge plasma actuators

Reducing emissions and improving combustion are necessary steps to reach greener combustion systems. In this study, the effect of employing an annular plasma actuator mounted on the surface of a bluff body in a non-premixed burner is numerically investigated. Activating the plasma actuator induces an ionic wind near the surface of the bluff body that modifies the flow features. While the previous relevant studies were mainly focused on volume dielectric barrier plasma discharges, this study investigates the influences of surface plasma discharges. Also, the effect of plasma actuator position, fuel-to-air velocity ratio, and the size of the bluff body are investigated. The characteristics of the flow and temperature fields, the mass fraction of carbon monoxide and carbon dioxide inside the burner in the presence, and the absence of a plasma actuator are analyzed. Also, spatial mixing deficiency (SMD) is used to evaluate the plasma actuator's influence on the reactants' mixing. The results show that among various configurations of annular plasma actuators, positioning the plasma actuator on the bluff body surface acting upwards near the air duct, strengthens the external recirculation region which leads to a favorable change in the characteristics of the flame inside the burner. With the activation of the plasma actuator, the spatial mixing deficiency (SMD) values decrease by an average of 12.75%, showing improvement in mixing, and the flame becomes more uniform compared to the baseline case leading to the reduction of CO concentration. In addition, the root of the flame is strengthened and the height of the body of the flame measured from the bluff body surface is reduced by about 43%. For both low and high fuel-to-air velocity ratios, the presence of a plasma actuator leads to a positive effect on the flame structure. For a high fuel-to-air velocity ratio, the external recirculation area has a favorable size. The created flame is elongated and the root of the flame is entirely away from the burner. When the plasma actuator is active, it causes the flame to get closer to the burner tip. For various diameters of the bluff body, the plasma actuator showed reasonable capability in altering the flame behavior. For larger bluff body diameters, the plasma actuator strengthens both recirculation zones, especially the external recirculation zone, leading to a uniform and shorter flame.

The Adrenal Gland of Squamata (Reptilia): A Comparative Overview.

The adrenal gland is a complex endocrine organ composed of two components: a steroidogenic tissue, which produces steroid hormones, and a chromaffin tissue, which mainly produces norepinephrine and epinephrine. Through evolution, their relationships with each other changed. They begin as isolated chromaffin and steroidogenic cell aggregates, typical of fish, and end with the advanced compact gland, typical of mammals, which consists of an external steroidogenic cortical zone and an internal chromaffin medullary zone. The adrenal gland of reptiles is unique because, with few exceptions, it is near the gonads and genital ducts, and the chromaffin and steroidogenic tissues are closely associated. However, the degree of mixing is variable. For example, in Squamata, the mixing degree of chromaffin and steroidogenic tissues, their reciprocal position in the gland, and the relative quantities of norepinephrine and epinephrine secreted by the chromaffin cells are extremely variable. This variability could be related to the phylogenetic history of the species. After a brief discussion of the adrenal gland and its main functions in vertebrates, this overview will examine the general characteristics of the adrenal gland of squamates, the differences in morphology of the gland, and the possible relationships with the phylogeny of the different species.

Numerical Simulation and Experimental Investigation of Variable Mass Flow in Horizontal Wellbores: Single-Phase and Multiphase Analysis

Considering the current limitations and restricted scope of existing experiments, as well as the absence of corresponding numerical simulation verifications and comparisons, and the lack of actual case studies of variable mass flow calculation and comparison, this study focuses on high production oilfields in the Mideast and South China Sea. The objective is to investigate single-phase and multiphase variable mass flow through numerical and experimental simulations. The study develops linear regression equations to establish the relationship between the mixture pressure drop caused by side flow and the velocities of the main flow, as well as the ratio between side and main flow velocities. Actual calculations using these equations are provided. The comprehensive analysis reveals that, for a fixed total flow rate, an increase in the side versus main injection velocity ratio leads to an increase in pressure loss before and after the injection hole. In single-phase flow, the friction factor for side hole flow is generally higher than that for only axial main flow, with the same total flow rate. In multiphase flow, when the gas-liquid ratio (GLR) is relatively large, the side flow has minimal impact on pressure drop, while at lower GLR values, the side flow significantly increases the pressure drops. When predicting the pressure drop for single-phase variable mass flow in horizontal wellbores, it is appropriate to consider only the mixture pressure drop caused by the closest hole to the calculation section, assuming the injection hole flow rates are approximately equal. In terms of predicting the productivity of single-phase variable mass flow, it is crucial to consider the mixture pressure drop. Neglecting the mixture pressure drop can lead to relatively larger productivity prediction results, with potential production rate errors exceeding 50%. The accuracy of the prediction is influenced by the ratio of mixture pressure drop to production pressure differential, and the pressure along the external zone of the screen pipe is higher when considering the mixture pressure drop compared to when it is neglected. Additionally, the flow rate along the external zone of the screen pipe becomes more non-uniform when the mixture pressure drop is considered. Furthermore, the findings from the single-phase and multiphase flow experiments suggest that significant deviations in production rates may occur in scenarios with low gas-liquid ratio (GLR), highlighting the need for further investigation in this area.

Study of main factors influencing unsteady-state temperature drop in oil tank storage under dynamic thermal environment coupling

With the increasing oil demand, the construction of oil energy reserves in China needs to be further strengthened. However, given that there has been no research on the main influencing factors of crude oil temperature drop in storage tanks under actual dynamically changing environments, this paper considers the influence of dynamic thermal environment and internal crude oil physical properties on the fluctuating changes in crude oil temperature. A theoretical model of the unsteady-state temperature drop heat transfer process is developed from a three-dimensional perspective. According to the temperature drop variation law of crude oil storage tank under the coupling effect of various heat transfer modes such as external forced convection, thermal radiation, and internal natural convection, the external dynamic thermal environment influence zone, the internal crude oil physical property influence zone, and the intermediate transition zone of the tank are proposed. And the multiple non-linear regression method is used to quantitatively characterize the influence of external ambient temperature, solar radiation, wind speed, internal crude oil density, viscosity, and specific heat capacity on the temperature drop of crude oil in each influencing zone. The results of this paper not only quantitatively explain the main influencing factors of the oil temperature drop in the top, wall, and bottom regions of the tank, but also provide a theoretical reference for oil security reserves under a dynamic thermal environment.

Simulations of laminar methane flames doped with iron nitrate/1-butanol aerosol in a novel matrix burner

A novel matrix burner enabled the investigation of aerosol-doped laminar low-pressure flames. Iron nitrate dissolved in 1-butanol was used as a typical model system, also found in the flame spray pyrolysis for synthesis of iron oxide. The state of the aerosol entering the flame front was quantified by single-droplet evaporation calculations. Three-dimensional simulations were conducted to quantify thermal losses and the impact of buoyancy on the deviation from an ideal one-dimensional approximation. Highly resolved simulations of the burner matrix confirmed the compact, external mixing zone and the flatness of the flame in the low-pressure operation. Simulations based on the one-dimensional approximation demonstrated the suitability of the experimental setup for reaction kinetics investigations. The results were compared and validated by temperature measurements and probing mass spectrometry. Based on investigations of the particle-producing flame, a hypothesis about the origin of gas-borne nanoparticles in the spray-flame synthesis process was derived. This work demonstrates the suitability of the novel matrix burner for the investigation of reaction kinetics in aerosol doped, quasi-premixed, flat flames using one-dimensional, laminar flame simulations.

The Dynamics and Driving Mechanisms of Rural Revitalization in Western China

By constructing a rural revitalization index evaluation system and using measurement models and software such as AHP, the entropy method, the BCG matrix, and GeoDetector, this paper quantitatively analyzed the evolution mode and driving mechanism of rural revitalization performance based on the research of 131 cities and autonomous prefectures in western China to further put forward relevant policy suggestions and establish a new framework that integrates “performance evaluation, evolution model, driving mechanism, and management strategy”. Findings: firstly, rural revitalization in western China showed slow development and significant regional heterogeneity, with a coefficient of variation of 0.46 or even higher; secondly, the different dimensions of rural revitalization and development varied greatly, with the order being: thriving businesses (about 0.04) &lt; effective governance (about 0.06) &lt; pleasant living environment (about 0.09) &lt; social etiquette and civility (about 1.0) &lt; prosperity (about 0.23); thirdly, the growth and decline of rural revitalization performance coexisted in the context of rapid development in western China, and the evolution was in diversified patterns; fourthly, there were many factors affecting the change of rural revitalization performance, and different factors exhibited significant synergistic effects with each other, with super-interacting factor pairs having a force of over 0. 7 (maximum 1), including permanent population, urbanization rate, added value of primary industry, and per capita GDP as key factors; fifthly, based on the superposition analysis of the evolution pattern and driving forces of rural revitalization, western cities are classified into 8 types (including external assistance zone, general development zone, general retention zone, general demonstration zone, internal governance zone, important development zone, important retention zone, important demonstration zone) for establishment of a zoning planning and management system and design of differentiated development policies, providing a basis for “evidence-based decision-making” for the government.

The effect of the dielectric barrier discharge plasma actuator in the control of non-reactive flow in a non-premixed bluff body burner

Active flow control methods based on dielectric barrier discharge plasma actuators can be used to increase the efficiency of combustion systems. In this study, the influence of the location of plasma actuators on the bluff body in a non-premixed burner on the non-reactive flow field of fuel and oxidizer is investigated numerically. Flow field properties and spatial mixing deficiency (SMD) are calculated to evaluate the plasma actuator's influence on the reactants' mixing inside the burner. The results show that the plasma actuator can influence the recirculation areas and are effective in mixing fuel and oxidizer. The presence of the plasma actuator results in the formation of a vortex, which slows down the movement of the flow and improves the mixing between the fuel and airflow streams resulting in more favorable combustion. The results show that at a higher air velocity (4 m/s), the formation of a plasma zone near the air duct strengthens the external circulation zone (ERZ) in such a way that it surrounds the internal recirculation zone and reduces the value of SMD by an average of 7.89%. While activating the actuator also strengthens the ERZ for a lower air velocity (0.3 m/s), this affects the air inflow, and the flow field becomes dominated by the fuel jet flow. When the diameter of the bluff body is increased, both when the plasma actuator is active or inactive, the ERZ is greatly strengthened, and the flow field is more dominated by the airflow.