Invasion and Dispersion of the Exotic Species Procambarus clarkii (Decapoda Cambaridae) in Yeongsan River Basin, South Korea

The introduction of exotic species negatively affects the distribution and interactions within local biological communities in an ecosystem and can threaten ecosystem health. This study aimed to provide the basic data required to manage P. clarkii in the Yeongsan River basin. We identified the dispersion pattern and evaluated the ecosystem risk of this newly introduced species. The distribution survey investigated Procambarus clarkii populations at 25 sites in the Yeongsan River basin over a four-year period. The initial introduction occurred in Jiseok Stream. The larvae of P. clarkii were most abundant in areas with a dense aquatic plant cover, whereas adults preferred silt/clay areas. The alterations in the water flow by the river refurbishment project (carried out in 2012) increased their preferred habitats and contributed to P. clarkii dispersion. However, stable isotope analysis showed that the dispersion has had little effect on the freshwater ecosystem. The interrelationship between P. clarkii (i.e., larvae and adults) and other biological communities has been limited. Although the rapid dispersion by P. clarkii in the Yeongsan River basin has not impacted the freshwater ecosystem, further ecological information is required on how to manage P. clarkii beyond this early stage of invasion.

Dispersion pattern of Mansonia in the surroundings of the Amazon Jirau Hydroelectric Power Plant

Mansonia spp. are voracious hematophagous mosquitoes whose mature stages usually breed in freshwater bodies containing aquatic vegetation. The reduction in water flow leads to a proliferation in aquatic plants, increasing their populations. Besides, some species are potential vectors of pathogens such as arboviruses and microfilariae. We evaluated the degree of active dispersion of females of Mansonia spp. in the surrounding area of the Jirau hydroelectric power plant in the Amazon, Rondônia, Brazil, using mark-release-recapture techniques. The flight behavior of the recaptured specimens was summarized with a set of average and maximum distances traveled. We show that the dispersal movement of Mansonia spp. is predominantly performed by random, low, and short flights, with a tendency to remain near the breeding sites in certain vegetation fragments. However, the maximum distances traveled were 2000 m from the release point for Mansonia amazonensis during 2018 and Mansonia humeralis during 2019.

Azimuthal multiple signal classification of dispersive and aliased surface waves recorded in 3D seismic acquisition

Irregular acquisition geometry causes discontinuities in the appearance of surface wave events, and a large offset causes seismic records to appear as aliased surface waves. The conventional method of sampling data affects the accuracy of the dispersion spectrum and reduces the resolution of surface waves. At the same time, ”mode kissing” of the low-velocity layer and inhomogeneous scatterers requires a high-resolution method for calculating surface wave dispersion. This study tested the use of the multiple signal classification (MUSIC) algorithm in 3D multichannel and aliased wavefield separation. Azimuthal MUSIC is a useful method to estimate the phase velocity spectrum of aliased surface wave data, and it represent the dispersion spectra of low-velocity and inhomogeneous models. The results of this study demonstrate that mode-kissing affects dispersion imaging, and inhomogeneous scatterers change the direction of surface-wave propagation. Surface waves generated from the new propagation directions are also dispersive. The scattered surface wave has a new dispersion pattern different to that of the entire record. Diagonal loading was introduced to improve the robustness of azimuthal MUSIC, and numerical experiments demonstrate the resultant effectiveness of imaging aliasing surface waves. A phase-matched filter was applied to the results of azimuthal MUSIC, and phase iterations were unwrapped in a fast and stable manner. Aliased surface waves and body waves were separated during this process. Overall, field data demonstrate that azimuthal MUSIC and phase-matched filters can successfully separate aliased surface waves.

Estimation of the spatial distribution of maximum PM10 and PM2.5 concentration in Bandung City and surrounding countries using WRF-Chem Model (case study in July and October 2018)

Bandung is one of big cities in Indonesia with high activities on industrial and transportation that will increase the air pollutant emission and causes adversely affect the public health. Based on that matter, monitoring of air pollutant concentration is urgently needed to predict the direction of pollutant dispersion and to analyze which locations are vulnerable to maximum exposure of the pollutant. Field monitoring of air pollutant concentration needs much time and high cost, but modeling could help for this. One of the models that can be used to predict the direction of pollutant distribution is the Weather Research Forecasting/Chemistry (WRF-Chem) model, which is a model that combines meteorological models with air quality models. The output of the WRF-Chem running model on July and October 2018, which has been analyzed visually, showed the dispersion pattern of PM10 and PM2.5 is spread mostly to the west, northwest, and north following the wind direction. According to the output of the WRF-Chem model, Bandung Kulon is the most polluted subdistrict by PM10 and PM2.5 with an exposure frequency of 22 hours (PM10), 24 hours (PM2.5) on July 2018 and 19 Hours (PM10), 14 hours (PM2.5) on October 2018. The correlation value for meteorological parameters is quite high in July 2018 (R = 0.9 for wind speed and R = 0.82 for air temperature). So based on the meteorological factor, WRF-Chem model can be used to predict the direction of pollutant distribution.

Review of the distribution of granite using geomagnetic methods at Bukit Nunggal Air Mesu Village, Pangkalan Baru Sub-District, Bangka Tengah District

Exploration is activities happens before the mining activity. It has purposes to know, predict and obtain the dimension in quality and quantity from a reserve that has economic value. From surveying at bukit Nunggal, Mesu Village, Pangkalan Baru Sub-district, Bangka Tengah District showed that there are outcrops indicating the potential for becoming a reserve for granite. Measurement is conducted to know the resource estimation and it is done by an approach of geomagnetic method that is environment friendly. Geomagnetic is passive method to measure the magnetism level or susceptibility from the measuring point. The total of the line to know the dispersion pattern and the depth of the resource is 13 lines with the space between measurement is 10m. From the geomagnetic measurement obtained IGRF value is 42969, inclined degree 0.424 declined degree – 21.157, susceptibility value in between -54.2nT to 56.1 nT, and the granite susceptibility value is in between 21 nT to 50nT. The anomalies map showed that there is a resource potential, and the dispersion is from east to west. Viewed from the topography and the residential areas, mining activity is recommended to be done in the west area.

Pore-Scale Simulation of the Interplay between Wettability, Capillary Number, and Salt Dispersion on the Efficiency of Oil Mobilization by Low-Salinity Waterflooding

Summary Nonuniform mixing during low-salinity waterflooding (LSWF) is a function of the pore geometry and flow patterns within the porous system. Salinity-dependent wettability alteration (WA) changes the entry capillary pressure, which may mobilize the trapped oil depending on the flow regime and salt dispersion pattern. The complex interplay between the wettability, capillary number (NCa), and salt dispersion caused by pore-scale heterogeneity on the efficiency of LSWF is not well understood. In this paper, direct numerical simulations in a pore-doublet model (PDM) were carried out with OpenFOAM® (OpenCFD, Berkshire, UK) using the volume-of-fluid (VOF) method. Oil trapping and remobilization were studied at relevant NCa as low as 10−6 under different initial wettability states. Depending on the effective salinity ranges (ESRs) for the low-salinity effect (LSE), three WA models were implemented, and the effects of WA degree and salinity distribution on LSWF flow dynamics were investigated. The slow process of WA by means of thin film phenomena was captured by considering a diffuse interface at the three-phase contact line. Because of the pore structure of the pore doublet, only in nonwater-wet cases, oil is trapped in the narrower side channel (NSC) after high-salinity waterflooding (HSWF) and may be remobilized by LSWF. In strongly oil-wet cases, oil is recovered gradually by LSWF by means of a film-flow mechanism near the outlet. In moderately oil-wet cases, however, the entire trapped oil ganglion can be mobilized, provided that the entry capillary pressure is sufficiently reduced. The degree of WA, ESR, kinetics of WA, and the wettability of pore surface at the outlet are determining factors in the drainage of the trapped oil. The salt dispersion pattern in the flowing region [i.e., wider side channel (WSC)] controls the wettability distribution and the rate and magnitude of oil recovery from the stagnant region (i.e., NSC). The difference between the WA models is more apparent near the outlet, where the salinity profile is more dispersed. The ESR in which WA occurs determines the speed of the entry capillary pressure reduction and, thus, the recovery factor. In cases where WA occurs at a salinity threshold (ST), the highest recovery is obtained, whereas with the full-salinity-range WA model, the oil recovery performance is lowest. From the capillary desaturation perspective, it is found that the LSE becomes more pronounced when NCa is less than 10−5, and the dispersion regime is in the power-law interval. Because the adverse effect of salt dispersion in the flowing region is delayed, the LSE is intensified. For the simulations to be representative of the actual conditions in the porous medium, much lower NCa than currently used in many research works must be studied. Otherwise, the simulations may lead to over- or underestimation of the LSE. The synergetic or antagonistic effects caused by the interplay between viscous and capillary forces and dispersion may lead to total recovery or entrapment of oil, regardless of WA. Based on the pore geometry, initial wettability state, and balance of forces, the mobilized oil may flow past the conjunction (favorable) or in the backward direction (unfavorable) to the WSC and get retrapped. Successful drainage of oil from the pore system after WA is essential for observing incremental oil recovery by LSWF.

Methane Emission Estimation and Dispersion Modeling for a Landfill in West Java, Indonesia

Methane gas (CH4) is a greenhouse gas that can potentially induce global warming and it is known as surface ozone precursor. CH4 is generally produced from biological process occurred at the landfill which is not equipped with CH4 recovery and treatment system. Note that, very few of landfills in Indonesia have been operated as sanitary landfill but rather most of them act as dumping site. One landfill in West Java Province is Sarimukti Landfill which receives nearly 604,674 ton of solid waste annually. Existing studies have been using the first tier of the Intergovernmental Panel on Climate Change (IPCC) guideline for the emission estimation which provides high uncertainty due to the international default data. In addition, there are uncertainties for the multi years estimation because the kinetic rate of biological processes was not involved in the calculation. To fill in this gap, this research was conducted to use an alternative of methodology for estimating CH4 from landfill using a well known software of the Landfill Gas Emissions Model (LandGEM) which facilitates biological reaction in the calculation. We will also perform calculations using the traditional IPCC method for the Sarimukti landfill as a case study. To quantify the impact of CH4 emission, its dispersion was calculated using the AMS/EPA Regulatory Model (AERMOD). Potential impact on surface ozone formation was assessed using ozone formation potential (OFP) metric. The results of this study indicate that methane gas emissions have increased every year, where the highest emissions occurred in 2025 of 14,810.41 Mg/year (LandGEM) and 11,462.66 Mg/year (IPCC). Likewise, the potential for OFP from methane gas concentrations has increased every year where the highest concentration of surface ozone formation is in 2025 of 183,40 Mg/year. Meanwhile, the methane emission (CH4) has a dispersion pattern which is influenced by meteorological factors around the Sarimukti landfill.

CT-guided transforaminal epidural steroid injection for discogenic lumbar radiculopathy: influence of contrast dispersion and radiologist’s experience on clinical outcome

Objective To investigate the impact of contrast dispersion pattern/location during lumbar CT-guided transforaminal epidural steroid injection (TFESI) and experience of the performing radiologist on therapeutic outcome. Materials and methods In this single-center retrospective cohort study, two observers analyzed contrast dispersion during CT-guided TFESI of 204 patients (age 61.1 ± 14 years) with discogenic unilateral single-level L4 or L5 radiculopathy. The contrast dispersion pattern was classified as “focal,” “linear,” or “tram-track”; the location was divided into “extraforaminal,” “foraminal,” or “recessal.” Pain was assessed before and 4 weeks after treatment using a numerical rating scale (0, no pain; 10, intolerable pain). Additionally, the patient global impression of change (PGIC) was assessed. The TFESI was performed by musculoskeletal radiologists (experience range: first year of musculoskeletal fellowship training to 19 years). Contrast pattern/location and radiologist’s experience were compared between “good responder” (≥ 50% pain reduction) and “poor responder” (< 50%). A p-value < 0.05 was considered to be statistically significant. Results Overall, CT-guided TFESI resulted in a substantial pain reduction in 46.6% of patients with discogenic radiculopathy. The contrast dispersion pattern and location had no effect on pain relief (p = 0.75 and p = 0.09) and PGIC (p = 0.70 and p = 0.21) 4 weeks after TFESI. Additionally, the experience of the radiologist had no influence on pain reduction (p = 0.92) or PGIC (p = 0.75). Regarding pre-interventional imaging findings, both the location and grading of nerve compression had no effect on pain relief (p = 0.91 and p = 0.85) and PGIC (p = 0.18 and p = 0.31). Conclusion Our results indicate that neither contrast agent dispersion/location nor the experience of the radiologist allows predicting the therapeutic outcome 4 weeks after the procedure.

Comparative assessment of fluorine, sodium, and lithium distributions in snow cover in Siberia

Based on field studies of the snow cover and systematization and analysis of scientific data and technical literature data, the distributions of fluorine, sodium, and lithium, as elements included in the raw materials used for aluminum production, in the snow cover in areas proximal to Siberian aluminum smelters were considered. The results showed that the changes in concentrations of fluorine, sodium, and lithium in the snow cover near various plants have the same dispersion pattern, which can be described by an exponential relationship. Exponential relationships of diminishing concentration with distance from the emission source had high correlation coefficients. From the examples established by these relationships, an assumption was made that the behavior of these aerosols in the atmosphere is determined by the general physical and chemical properties, irrespective of the technologies and natural climatic regions of the plant locations. It is suggested that deposition of aerosols from industrial aluminium production can be achieved at a minimum distance from the plants or within the plant area through particle enlargement by various technological methods in aluminium production or by changing the atmospheric scattering capacity.