Thermal Outflows Research Articles

Galactic outflows in different geometries

In the gravitational potential well of a galaxy, the behavior of outflows has been studied in different geometries i.e. constant flux tube, divergent and extreme divergent environments. First of all, we describe the hydrodynamic model by which we approach the outflows system. This model treats all the waves as fluids and applies fluid mechanics to them(cosmic rays, thermal plasma & Alfvén wave). Whereas outflows mean the gas regime above and below the center of the galactic disk, and we have taken it as a system where interaction between cosmic rays and plasma occurs. After discussing the hydrodynamic three-fluid model, we define three geometrical structures which can be acquired by outflows and relate these structures with thermal plasma, cosmic and Alfvén waves pressures, thus seeking for its behavior. The solution of the system is categorically divided into three branches, supersonic, subsonic and unphysical solutions.The most interesting of all is the transonic solution, a solution that evolves from subsonic to supersonic. First of all, we discuss only thermal plasma outflows and explain their evolution in three cases of outflows environments, followed by the addition of cosmic waves and Alfvén waves. After discussing three fluid outflows in different structures, we compared the results of thermal outflows with three fluid outflows and see how the addition of waves in the system affects the dynamics of the system. At last, the findings of this paper are discussed.

Counterstreaming Cold H+, He+, O+, and N+ Outflows in the Plasmasphere

The Naval Research Laboratory (NRL) Sami3 is Also a Model of the Ionosphere (SAMI3) ionosphere/plasmasphere code is used to examine H+, He+, N+, and O+ thermal outflows during a storm. Here, H+ and He+ outflows are associated with refilling while O+ and N+ outflows are associated with ring current heating. An improved model of counterstreaming H+ outflows from the two hemispheres is presented, using an implementation of SAMI3 with two fluid species for H+. The two-fluid H+ model avoids nonphysical high-altitude “top-down refilling” density peaks seen in one-fluid H+ simulations. Counterstreaming cold ion populations are found in all cases. In these fully three-dimensional simulations with realistic magnetosphere boundary conditions, nonphysical top-down refilling density peaks were milder than those found in previous single-field-line or single-magnetic-longitude simulations. In the present two-fluid H+ case, “bottom-up refilling” density peaks were so mild as to be difficult to detect. For O+ and N+, the nonphysical high-altitude density peak is a brief (1–2 h) transient that occurs when heating-driven northward and southward flows first meet. In general, He+ outflows mimic H+ outflows while N+ outflows mimic O+ outflows.

Thermal baths as sources of pharmaceutical and illicit drug contamination

Despite the fact that there are tens of thousands of thermal baths in existence, knowledge about the occurrence of pharmaceutically active compounds (PhACs) in untreated thermal wastewater is very limited. Because used thermal water is typically legally discharged into surface waters without any treatment, the effluent poses environmental risks for the receiving water bodies. The aim of this study was to show the occurrence patterns and spatiotemporal characteristics of 111 PhACs in thermal wastewater. Six thermal water outflows of different thermal baths were tested in different seasons in the Budapest metropolitan region (Hungary), and diurnal analysis was performed. After solid-phase extraction, the samples were analysed and quantified by coupling supercritical fluid chromatography and mass spectrometry to perform simultaneous multi-residue drug analysis. The results confirm that water discharge pipes directly transport pharmaceuticals into surface water bodies; 34 PhACs were measured to be over the limit of quantification at least once, and 21 of them were found in more than one water sample. The local anaesthetic drug lidocaine, antiepileptic carbamazepine, analgesic derivative tramadol and illicit drug cocaine were detected in more than half of the samples. Caffeine, metoprolol and bisoprolol (cardiovascular drugs), benzoylecgonine (cocaine metabolite), diclofenac (NSAID), citalopram (antidepressant) and certain types of hormones also have a significant frequency of 30-50%. However, the occurrence and concentrations of PhACs vary according to the season and number/types of visitors. As demonstrated by the diurnal fluctuation, drug contamination of thermal waters can significantly vary, even for similar types of baths; furthermore, the quantity and types of some pollutants rapidly change in the discharged thermal wastewater.

Three-dimensional GRMHD Simulations of Neutrino-cooled Accretion Disks from Neutron Star Mergers

Abstract Merging binaries consisting of two neutron stars (NSs) or an NS and a stellar-mass black hole typically form a massive accretion torus around the remnant black hole or long-lived NS. Outflows from these neutrino-cooled accretion disks represent an important site for r-process nucleosynthesis and the generation of kilonovae. We present the first three-dimensional, general-relativistic magnetohydrodynamic (GRMHD) simulations including weak interactions and a realistic equation of state of such accretion disks over viscous timescales (380 ms). We witness the emergence of steady-state MHD turbulence, a magnetic dynamo with an ∼20 ms cycle, and the generation of a “hot” disk corona that launches powerful thermal outflows aided by the energy released as free nucleons recombine into α-particles. We identify a self-regulation mechanism that keeps the midplane electron fraction low (Y e ∼ 0.1) over viscous timescales. This neutron-rich reservoir, in turn, feeds outflows that retain a sufficiently low value of Y e ≈ 0.2 to robustly synthesize third-peak r-process elements. The quasi-spherical outflows are projected to unbind 40% of the initial disk mass with typical asymptotic escape velocities of 0.1c and may thus represent the dominant mass ejection mechanism in NS–NS mergers. Including neutrino absorption, our findings agree with previous hydrodynamical α-disk simulations that the entire range of r-process nuclei from the first to the third r-process peak can be synthesized in the outflows, in good agreement with observed solar system abundances. The asymptotic escape velocities and quantity of ejecta, when extrapolated to moderately higher disk masses, are consistent with those needed to explain the red kilonova emission following the NS merger GW170817.

Exergy-Based Formulation for Aircraft Aeropropulsive Performance Assessment: Theoretical Development

Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for an efficient design process. A theoretical formulation based on exergy management is proposed for assessing the aeropropulsive performance of future aircraft configurations. It consists of the combination of a momentum balance and a fluid flow analysis involving the first and second laws of thermodynamics. The exergy supplied by the propulsion system and its partial destruction within the control volume is associated with the aircraft mechanical equilibrium. Characterization of the recoverable mechanical and thermal outflows is made along with the identification of the irreversible phenomena that destroy their work potential. Restriction of the formulation to unpowered configurations yields connections to some well-known far-field drag expressions and shows that their underlying theory can be related to exergy considerations. Because the exergy balance does not rely on the distinction of thrust and drag, it is especially suitable for the performance evaluation of highly integrated aeropropulsive concepts like boundary-layer ingestion.

Characteristics of thermal ion outflows in the polar cap according to data of the Interball-2 satellite

Characteristics of polar wind fluxes at a height of ∼20000 km measured by the Hyperboloid mass-spectrometer installed onboard the Interball-2 satellite are presented in the paper. The characteristics are presented for the upwelling flows of ionospheric ions H+, He+, and O+ from the sunlit polar cap in the period of solar activity minimum. Orbit segments with minimal precipitation of magnetospheric ions and electrons were preliminarily selected, and the measurements where the fluxes of ions coming from the cusp/cleft were excluded as carefully as possible. Thus, the densities, field-aligned velocities, and temperatures of ions in the regions where fluxes of polar wind could be detected with the maximal probability degree are presented in the paper. It is found that cases when only H+ ions are reaching the detector are with high probability the polar wind outflows. Their characteristics agree well with the Tube-7 hydrodynamic model and are as follows: n ≈ 1.5 cm−3, V∥ ∼ 21 km/s; T∥ = 3500 K, and T⊥ = 2000 K. In cases when He+ and O+ ions are also detected, the temperatures are substantially higher than the model ones, and the measured field-aligned velocities of O+ fluxes are several times higher than the model ones. Moreover, it was revealed that the polar wind outflows are predominantly observed in the polar cap regions where the polar rain fluxes are very small.

Threatened fishes of the world: Cyprinodon bifasciatus Miller 1968 (Cyprinodontidae)

Common Names: Cuatrociengas pupfish, cachoritto de Cuatrociengas. Conservation Status: Listed as Threatened (SEMARNAT 2002). Current IUCN Red List status: Lower Risk/least concern. Identification: Morphologically streamlined. Mature males are chalky blue, have yellow eyes, and a thin, terminal black band on the caudal fin. Females and juveniles have two dark brown lateral lines, with a light blue to pale brown base color. Juveniles and adults have no ocellus on dorsal or anal fin. Mature males range from 30.9 to 51.4 mm SL, mature females from 29.5 to 41.3 mm SL (Miller 1968). Image: modification of mature male holotype in Miller (1968). Distribution: Endemic to the Cuatrociengas basin, Coahuila, Mexico. Abundance: Abundant, with generally large and stable populations throughout its range. Habitat and ecology: Inhabits stable, physicochemically benign thermal springs, outflows, and rivers (Miller 1968; Minckley 1969). Young are omnivorous, but diet is largely plant/ sediment based after 24–29 mm SL (Arnold 1972). Co-occurs with many fish species (Miller 1968) and is stenoplastic (Carson et al. 2008). Often sympatric with C. atrorus in intermediate environments, where natural hybridization is extensive. Ancient hybridization led to complete replacement of C. bifasciatus mitochondrial genome by that of C. atrorus, but nuclear gene introgression from C. atrorus appears minor to absent (Carson and Dowling 2006). Reproduction: Mature males breed and feed in leks in shallow water. Mature females school and feed in deeper water, entering leks to spawn. Breeding occurs year-round, though is reduced in winter (Arnold 1972). Threats: Groundwater extraction is primary. Expanded eco-tourism and introduction of non-native species are also of concern. Conservation action: In 1994 the Cuatrociengas basin was declared a Natural Protected Area by the Mexican government. Conservation efforts since have been weakly-effective (Figueroa and Sanchez-Cordero 2008). Conservation recommendations: Elimination of groundwater extraction is urgently needed. Effective conservation strategies need to be devised and implemented. Environ Biol Fish (2009) 86:445–446 DOI 10.1007/s10641-009-9546-8

Origin and evolution of the Steamboat Springs siliceous sinter deposit, Nevada, U.S.A.

Siliceous hot spring deposits from Steamboat Springs, Nevada, U.S.A., record a complex interplay of multiple, changing, primary environmental conditions, fluid overprinting and diagenesis. Consequently these deposits reflect dynamic geologic and geothermal processes. Two surface sinters were examined—the high terrace, and the distal apron-slope, as well as 13.11 m (43 ft) of core material from drill hole SNLG 87-29. The high terrace sinter consists of vitreous and massive-mottled silica horizons, while the distal deposit and core comprise dominantly porous, indurated fragmental sinters. Collectively, the three sinter deposits archive a complete sequence of silica phase diagenetic minerals from opal-A to quartz. X-ray powder diffraction analyses and infrared spectroscopy of the sinters indicate that the distal apron-slope consists of opal-A and opal-A/CT mineralogy; the core yielded opal-A/CT and opal-CT with minor opal-A; and the high terrace constitutes opal-C, moganite, and quartz. Mineralogical maturation of the deposit produced alternating nano–micro–nano-sized silica particle changes. Based on filament diameters of microbial fossils preserved within the sinter, discharging thermal outflows fluctuated between low-temperatures (< 35 °C, coarse filaments) and mid-temperatures (∼ 35–60 °C, fine filaments). Despite transformation to quartz, primary coarse and fine filaments were preserved in the high terrace sinter. AMS 14C dating of pollen from three horizons within core SNLG 87-29, from depths of 8.13 to 8.21 m (26′8″ to 26′11″), 10.13 to 10.21 m (33′3″ to 33′6″), and 14.81 to 14.88 m (48′7″ to 48′10″), yielded dates of 8684 ± 64 years, 11,493 ± 70 years and 6283 ±60 years, respectively. In the upper section of the core, the stratigraphically out-of-sequence age likely reflects physical mixing of younger sinter with quartzose sinter fragments derived from the high terrace. Within single horizons, mineralogical and morphological components of the sinter matrix were spatially patchy. Overall, the deposit was modified by sub-surface flow of alkali-chloride thermal fluids depositing a second generation of silica, and periodically, by acidic steam condensate formed during periods when the water table was low. Local faulting produced considerable fracturing of the sinter. Hence, the Steamboat Springs sinter experienced a complex history of primary and secondary hydrothermal, geologic and diagenetic events, and their inter-relationships and effects are locked within the physical, chemical and biological signatures of the deposit.

Assessment of thermal circulations in strike-slip fault systems: the Terme di Valdieri case (Italian western Alps)

Abstract Individual faults, faults linking at depth in flower structure zones and jogs bounded by faults are common structural elements in strike–slip fault systems and can play an important role in controlling thermal fluid flows. This paper explores the influence of these structures on the thermal circulations and fluid outflows of Terme di Valdieri, in the crystalline basement of the Argentera Massif (western Alps). In this site, thermal waters upwell at the tip of a NW-trending right-lateral fault, but exactly which structures control infiltration of meteoric waters and deep circulation is not clear from field surveys. Three-dimensional thermohydraulic numerical models calculated in steady-state and in transient regimes are presented for three alternative hypotheses. These account for circulations occurring: (i) within a single fault and adjoining host rocks; (ii) in faults intersecting at depth; and (iii) in faults interacting by means of a permeable step-over. The simulations show that advective flows can coexist with convective flows in models (i) and (iii), provided that the fault permeabilities are higher than 2×10 −13 m 2 , while advection prevails in model (ii) at all values of permeability. Model (iii) achieves the best fit to the data under the assumption of advective and convective flows. This finding provides a first quantitative estimate of the importance of jog structures bounded by strike–slip faults in favouring thermal outflows. Moreover, the numerical results suggest that thermal convection can coexist with advection also in mountainous settings.

Hot Accretion with Conduction: Spontaneous Thermal Outflows

Motivated by the low collisionality of gas accreted onto black holes in Sgr Aand other nearby galactic nuclei, we study a family of two-dimensional advective accretion solutions with thermal conduction. While we only impose global inflow,the accretionflow spontaneously develops bipolar outflows.The role of conduction is key in providing the extra degree of freedom (latitudinal energy transport) necessary to launch these rotating thermal outflows. The signoftheBernoulliconstantdoesnotdiscriminate betweeninflowingandoutflowingregions.Ourparametersurvey covers mass outflow rates from � 0% to 13% of the net inflow rate, outflow velocities from � 0% to 11% of the local Keplerian velocity, and outflow opening angles from � 0 � to 60 � . As the magnitude of conduction is increased, out- flows canadopt aconical geometry,pureinflow solutionsemerge, andthelimit oftwo-dimensional nonrotatingBondi- like solutions is eventually reached. These results confirm that radiatively inefficient, hot accretion flows have a hydrodynamic propensity to generate bipolar thermal outflows. Subject headingg accretion, accretion disks — black hole physics — conduction — hydrodynamics Online material: color figures

Investigating damselfly populations at springs in Banff National Park, Canada, with special focus on Argia vivida, Amphiagrion abbreviatum, and Ischnura cervula (Odonata: Coenagrionidae)

The objective of this study was to estimate Argia vivida (Odonata: Coenagrionidae) populations, identify breeding habitat, and investigate movement of adults within Banff National Park, Alberta, Canada, during the summer of 2003. Mark-recapture techniques and standardized dip-net surveys were used to monitor Argia vivida at various life stages. A reproductive index identified which sites Argia vivida recognized as suitable breeding habitat, and exuvia surveys confirmed breeding sites. The basic structure of emergent and surrounding vegetation was measured to investigate the importance of available ovipositing or roosting sites and the condition of the matrix habitat. Data was recorded for Amphiagrion abbreviatum and Ischnura cervula (both Odonata: Coenagrionidae) to determine if these spring-associated damselflies were successfully breeding within Banff National Park. Comparisons were made between the highly protected Middle Springs and the heavily altered Cave & Basin Springs. Additional surveys at the Vermilion Lake cool spring and Middle Springs Bog investigated their use as breeding habitat for Amphiagrion abbreviatum and Argia vivida, respectively. Results suggest the ecological value of thermal springs extends beyond their origin to outflows and downstream pools. Conservation of Argia vivida must recognize the value of unobstructed thermal outflows, and consider the condition of the forested habitat surrounding springs with regard to its potential use as nocturnal roosts and dispersal corridors. Amphiagrion abbreviatum was confirmed breeding within Banff National Park, while no sign of breeding activity was recorded for Ischnura cervula.

Circularly Polarized Radio Emission from an X-Ray Protostar

IRS 5, an embedded young stellar object in the nearby Corona Australis molecular cloud, was recently detected as an X-ray source with the ASCA and ROSAT satellites. We report here the detection of circularly polarized continuum emission from IRS 5 at centimeter wavelengths. Already known to be a highly variable radio source, the polarization fraction is seen to range from V/I10% to 37% on a day timescale. This demonstrates that radio emission from protostars, previously attributed in most cases to ionized thermal outflows, can sometimes arise instead from nonthermal processes, i.e., gyrosynchrotron emission from particles accelerated in situ by magnetic reconnection flares. Together with the X-ray data and indications of MeV particles in the solar nebula obtained from meteoritic materials, it contributes to the growing evidence for high-energy processes during the earliest stages of low-mass star formation.

“Cost-benefit” analysis of a state-wide hypertension screening program: Thomas R. Sharpe, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677; Benjamin F. Banahan III

Siliceous hot spring deposits from Steamboat Springs, Nevada, U.S.A., record a complex interplay of multiple, changing, primary environmental conditions, fluid overprinting and diagenesis. Consequently these deposits reflect dynamic geologic and geothermal processes. Two surface sinters were examined—the high terrace, and the distal apron-slope, as well as 13.11 m (43 ft) of core material from drill hole SNLG 87-29. The high terrace sinter consists of vitreous and massive-mottled silica horizons, while the distal deposit and core comprise dominantly porous, indurated fragmental sinters. Collectively, the three sinter deposits archive a complete sequence of silica phase diagenetic minerals from opal-A to quartz. X-ray powder diffraction analyses and infrared spectroscopy of the sinters indicate that the distal apron-slope consists of opal-A and opal-A/CT mineralogy; the core yielded opal-A/CT and opal-CT with minor opal-A; and the high terrace constitutes opal-C, moganite, and quartz. Mineralogical maturation of the deposit produced alternating nano–micro–nano-sized silica particle changes. Based on filament diameters of microbial fossils preserved within the sinter, discharging thermal outflows fluctuated between low-temperatures (< 35 °C, coarse filaments) and mid-temperatures (∼ 35–60 °C, fine filaments). Despite transformation to quartz, primary coarse and fine filaments were preserved in the high terrace sinter. AMS 14C dating of pollen from three horizons within core SNLG 87-29, from depths of 8.13 to 8.21 m (26′8″ to 26′11″), 10.13 to 10.21 m (33′3″ to 33′6″), and 14.81 to 14.88 m (48′7″ to 48′10″), yielded dates of 8684 ± 64 years, 11,493 ± 70 years and 6283 ±60 years, respectively. In the upper section of the core, the stratigraphically out-of-sequence age likely reflects physical mixing of younger sinter with quartzose sinter fragments derived from the high terrace. Within single horizons, mineralogical and morphological components of the sinter matrix were spatially patchy. Overall, the deposit was modified by sub-surface flow of alkali-chloride thermal fluids depositing a second generation of silica, and periodically, by acidic steam condensate formed during periods when the water table was low. Local faulting produced considerable fracturing of the sinter. Hence, the Steamboat Springs sinter experienced a complex history of primary and secondary hydrothermal, geologic and diagenetic events, and their inter-relationships and effects are locked within the physical, chemical and biological signatures of the deposit.