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Geography

Surface-active substances in a laboratory simulated Titan's organic haze: Prebiotic microstructures
submitted by gom 17 hours ago - Topic: Geography
Titan, the largest satellite of Saturn, is a key planetary body for astrobiological studies due to its active organic chemistry, hydrocarbon lakes and possible subsurface water-ammonia liquids. We have investigated the physicochemical properties of organic compounds synthesized in a simulated Titan atmosphere. A laboratory analogue of Titan's aerosols, called tholin, was produced by irradiation...



Numerical tests for effects of various parameters in niching genetic algorithm applied to regional waveform inversion
submitted by reatardella 18 hours ago - Topic: Geography
In this paper, we focus on the influences of various parameters in the niching genetic algorithm inversion procedure on the results, such as various objective functions, the number of the models in each subpopulation, and the critical separation radius. The frequency–waveform integration (F–K) method is applied to synthesize three-component waveform data with noise in various epicentral dis...

Seismic wave modeling in viscoelastic VTI media using spectral element method
submitted by reatardella 18 hours ago - Topic: Geography
Spectral element method (SEM) for elastic media is well known for its great flexibility and high accuracy in solving problems with complex geometries. It is an advanced choice for wave simulations. Due to anelasticity of earth media, SEM for elastic media is no longer appropriate. On fundamental of the second-order elastic SEM, this work takes the viscoelastic wave equations and the vertical tr...

Embedding complex hydrology in the regional climate system – dynamic coupling across different modelling domains
submitted by sdf 19 hours ago - Topic: Geography
To improve our understanding of the impacts of feedback between the atmosphere and the terrestrial water cycle including groundwater and to improve the integration of water resource management modelling for climate adaption we have developed a dynamically coupled climate-hydrological modelling system. The OpenMI modelling interface is used to couple a comprehensive hydrological modelling system...

The Relationship between an Invasive Shrub and Soil Moisture: Seasonal Interactions and Spatially Covarying Relations
submitted by evanni 19 hours ago - Topic: Geography
Recent studies indicate that positive relationships between invasive plants and soil can contribute to further plant invasions. However, it remains unclear whether these relations remain unchanged throughout the growing season. In this study, spatial sequences of field observations along a transect were used to reveal seasonal interactions and spatially covarying relations between one common in...



Environmental upheavals of the Ediacaran period and the Cambrian “explosion” of animal life
submitted by mantodo234 19 hours ago - Topic: Geography
The second half of the Ediacaran period began with a large impact - the Acraman impact in South Australia, which was accompanied by a negative δ 13Ccarb anomaly and an extinction-radiation event involving acritarchs. A few million years later (∼570 Ma?) there was a second, deeper and longer-lived world-wide δ 13Ccarb anomaly (the Shuram anomaly) which coincides with extinction of the acanth...

Influences of northward propagating 25–90-day and quasi-biweekly oscillations on eastern China summer rainfall
submitted by msheroze 20 hours ago - Topic: Geography
The present study reveals that rainfall anomalies associated with the 25–90-day (quasi-biweekly) tropical convective activity propagates northward (northwestward) into northern China (the Yangtze River). Enhanced rainfall over southern China results directly from enhanced convection propagating northward from the South China Sea (SCS)–western north Pacific (WNP), strengthened northward wate...


An ensemble climate projection for Africa
submitted by msheroze 20 hours ago - Topic: Geography
The Met Office Hadley Centre’s PRECIS regional climate modelling system has been used to generate a five member ensemble of climate projections for Africa over the 50 km resolution Coordinated Regional climate Downscaling Experiment-Africa domain. The ensemble comprises the downscaling of a subset of the Hadley Centre’s perturbed physics global climate model (GCM) ensemble chosen to exclud...

Interannual and intra-annual variability of rainfall in Haiti (1905–2005)
submitted by msheroze 20 hours ago - Topic: Geography
The interannual variability of annual and monthly rainfall in Haiti is examined from a database of 78 rain gauges in 1905–2005. The spatial coherence of annual rainfall is rather low, which is partly due to Haiti’s rugged landscape, complex shoreline, and surrounding warm waters (mean sea surface temperatures >27 °C from May to December). The interannual variation of monthly rainfall is m...


Suitability of UNS S31603 steel for geothermal brines in volcanic areas – Influence of different physicochemical conditions on its corrosion behavior
submitted by rhstaathaff 20 hours ago - Topic: Geography
Geothermal sources are found to be the most aggressive natural environments for construction materials in terms of corrosion. This study was focused on investigating the suitability of stainless steel UNS S31603 in volcanic areas of geothermal sites Sibayak and Lahendong (Indonesia). Influence of different factors (temperatures up to 175°C, chloride content up to 1500mg/L and pH down to 2) was...

Gaining insight into regional coastal changes on La Réunion island through a Bayesian data mining approach
submitted by soaram1222 20 hours ago - Topic: Geography
Recent works have highlighted the interest in coastal geographical databases - collected for coastal management purposes - for obtaining insight into current shoreline changes. On La Réunion, a tropical volcanic high island located in the Southern Indian Ocean, a dataset is available which describes shoreline changes, the coastal geomorphology and the presence of anthropic structures. This dat...


Analytical Observability Analysis of INS with Vehicle Constraints
submitted by forilolefeyoh 21 hours ago - Topic: Geography
Vehicle constraints have been gaining increased popularity as a means to mitigate drift of Inertial Navigation Systems in GNSS deprived settings. While useful, such constraints cannot compensate for the drift of all state variables in the navigation solution. To study which variables are affected, empirical analyses under typical scenarios are commonly performed, however, no insight is provided...

Studies of methyldiethanolamine process simulation and parameters optimization for high-sulfur gas sweetening
submitted by samonothco 22 hours ago - Topic: Geography
The energy consumption of high-sulfur gas sweetening was significantly higher than conventional gas, in order to save energy, a novel Methyldiethanolamine (MDEA) modified process is discussed in this paper. The law of operating conditions' impact on gas sweetening efficiency and economic benefits has been obtained by using process simulation and optimization. The results showed that the maximiz...

Wellbore stability model for shale gas reservoir considering the coupling of multi-weakness planes and porous flow
submitted by samonothco 22 hours ago - Topic: Geography
Irregular wellbore collapse phenomena and accidents frequently occur during drilling operations in Longmaxi shale gas reservoir. Considering shale formation with natural cross beddings and fractures, we propose a multi-weakness plane instead of a single weakness plane failure model. Shale samples obtained from the Lower Silurian Longmaxi Strata of Sichuan Basin are investigated based on charact...

Experimental study of the microscopic fractal characteristics of limestone etched by acid
submitted by samonothco 22 hours ago - Topic: Geography
For an acid fracturing treatment, the conductivity of fractures strongly depends on both macroscopic reaction rate and microscopic etched characteristics of fracture walls. A series of experiments of reaction between acid and limestone have been done using orthogonal arrays. Acid concentration, reaction temperature, reaction time and acid type were taken into account. The influences of these fa...