Terrestrial Condition Research Articles

10806 高Pr数流体における液柱内マランゴニ対流の振動流遷移に対する液柱サイズの影響(OS6-1【熱流体工学のフロンティア(1)】)

Thermocapillary convection is known that flow affects the quality of grown crystal by a Floating Zone (FZ) method. Half zone system is often employed to understand a nature of flow behavior as a simplified model. Two-dimensional steady flow transits to three dimensional oscillatory one at critical temperature difference ΔT_C between supporting disks. This transition condition is organized using critical Marangoni number. The objective of this study is to investigate influence of size on the onset condition of oscillatory flow by comparing experimental results both under terrestrial condition and microgravity aboard the International Space Station. Consequently, it is found that ΔT_C depends on liquid bridge size and linearly decreases with a growing number of liquid bridge length.

Paleoclimate Reconstruction during Mamu Formation (Cretaceous) Based on Clay Mineral Distributions

Paleoclimate was reconstructed by the clay mineral assemblages within the age of Cretaceous (Campanian - Maastrichtian) of the Mamu Formation. To compare with clay mineral assemblages in this formation, selected samples were collected from sections along the road cuts from the King Petrol Station up the Miliken Hills and at the left bank of River Ekulu near the bridge to Onyeama mine, around Iva Valley and along Enugu Port-Harcourt road in Enugu State. Collected samples were prepared using standard clay mineral methodology. Their identification was made on X-Ray diffractographs, Kaolinite covered a range of 22-45%, its variation style in this formation could be a marker of climate changes from wet to dry which is supported by the lithological changes. Illite percentage varies from 5-10 and increases from Enu.1.1-1.5 to Enu.2.1-2.5. This may be due to dominant dry climate. Montmorrilonite ranges from 7 - 10% and its presence is due to terrestrial depositional condition. It seems thus, the present results can be indicated a possible procedure for ancient climate changes evaluation.

Bulk Growth of InGaSb Alloy Semiconductor under Terrestrial Conditions: A Preliminary Study for Microgravity Experiments at ISS

As a preliminary experiment for the growth of InGaSb alloy crystals under microgravity at International Space Station (ISS), bulk crystal was grown under terrestrial condition using the same gradient heating furnace (GHF). Czochralski grown GaSb <111>B single crystal was used as a seed and feed crystals for the growth of InGaSb bulk crystals. During the growth, heat pulses were intentionally introduced periodically to create the growth striations. From the striations, the growth rate of the grown crystal was estimated. The results show that the growth rate was gradually increased from the beginning of the growth and became stable. On the other hand the In composition of the grown crystal decreased along the growth direction. From the In composition, the temperature gradient in the solution was estimated and it was almost the same of that fixed during the growth.

A marine stem-tetrapod from the Devonian of western North America.

The origin of terrestrial vertebrates represents one of the major evolutionary and ecological transformations in the history of life, and the established timing and environment of this transition has recently come under scrutiny. The discovery and description of a well-preserved fossil sarcopterygian (fleshy-limbed vertebrate) from the Middle Devonian of Nevada helps to refine and question aspects of the temporal and anatomical framework that underpins the tetrapod condition. This new taxon, Tinirau clackae, demonstrates that substantial parallelism pervaded the early history of stem-tetrapods, raises additional questions about when digited sarcopterygians first evolved, and further documents that incipient stages of the terrestrial appendicular condition began when sarcopterygians still retained their median fins and occupied aquatic habitats.

Containerless Solidification and Characterization of Industrial Alloys (NEQUISOL)

Containerless solidification using electromagnetic levitator (EML), gas atomization and an instrumented drop tube, known as impulse atomization is investigated for Al-Fe and Al-Ni alloys. The effects of primary phase and eutectic undercooling on the microstructure of Al-Fe alloys are investigated using the impulse drop tube and parabolic flight. The TEM characterization on the eutectic microstructure of impulse-atomized Al-Fe powders with two compositions showed that the metastable AlmFe formed in these alloys. Also, the growth undercooling that the dendritic front experiences during the solidification of the droplet resulted in variation of dendrite growth direction from <100> to <111>. For Al-4 at%Fe, it was found that in reduced-gravity and in the impulse-atomized droplets the primary intermetallic forms with a flower-like morphology, whereas in the terrestrial EML sample it has a needle like morphology. For Al-Ni, the effect of primary phase undercooling on dendrite growth velocity under terrestrial and reduced-gravity condition is discussed. It is shown that under terrestrial conditions, in the Ni-rich alloys with increasing undercooling the growth velocity increases, whereas in the Al-rich alloys the growth velocity decreases. However, the Al-rich alloy that was studied in reduced-gravity showed similar behavior to that of Ni-rich alloys. Furthermore, the effect of cooling rate on the phase fractions and metastable phase formation of impulse-atomized Al-Ni alloys is compared with EML. A microsegregation model for the solidification of Al-Ni alloys is applied to impulse atomized powders. The model accounts for the occurrence of several phase transformations, including one or several peritectic reactions and one eutectic reaction.

Clay Mineralogical Composition of the Quaternary Sediments Collected in the North Coast of Ariake Bay, and the Relation to Depositional Environment and Weathering in the Terrestrial Condition

Clay Mineralogical Composition of the Quaternary Sediments Collected in the North Coast of Ariake Bay, and the Relation to Depositional Environment and Weathering in the Terrestrial Condition

The long bone histology of Ceresiosaurus (Sauropterygia, Reptilia) in comparison to other eosauropterygians from the Middle Triassic of Monte San Giorgio (Switzerland/Italy)

Ceresiosaurus is a secondarily marine reptile that lived during the Middle Triassic (Ladinian–Anisian) in a subtropical lagoonal environment with varying open marine influences. The genus comprises two species, Ceresiosaurus calcagnii and C. lanzi, and represents one of the largest vertebrate of up to 3-m snout-tail length from the UNESCO World Heritage site Monte San Giorgio, which is settled along the Swiss–Italian border. Earlier morphological studies identified this genus as basal sauropterygian still possessing many similarities with the plesiomorphic ancestral terrestrial condition. Interspecific morphological variation was interpreted as indicator for different habit(at) preferences by ascribing two locomotion types for each of the species. In this study, detailed data on the microstructure of the long bones are given and findings were put into a palaeoecological and phylogenetic context in comparison to other sauropterygians from Monte San Giorgio. Results showed that both Ceresiosaurus species retain a calcified cartilaginous core in the medullary region in at least young individuals. They both exhibit cyclical bone growth of lamellar to parallel-fibred bone matrices with undulating incremental growth marks and low to moderate vascularisation (lamellar-zonal bone tissue type). Interspecific variation comprises differences in the distribution of differently organised bone matrices and the size, orientation and number of vascularisation. The vascularisation pattern (abundance and orientation of the canals) of the pachyosteosclerotic long bones of C. calcagnii mostly resembles the histotype of the stratigraphically youngest pachypleurosaurid from Monte San Giorgio, Neusticosaurus edwardsii (except for the presence of primary osteons in the cortex of the former). The bone sample of C. lanzi is only osteosclerotic and most similar to young Nothosaurus (except for the irregular presence of fibrolamellar bone in the latter). The slightly different growth pattern already at young ontogenetic stages might be linked to a different mode of life within the restricted lagoonal basin for Ceresiosaurus, which supports previous studies on the morphological data that ascribed two different locomotion types.

A ‘Woollgari-Zone Mosasaur’ (Squamata; Mosasauridae) from the Carlile Shale (Lower Middle Turonian) of Central Kansas and the Stratigraphic Overlap of Early Mosasaurs and Pliosaurid Plesiosaurs

Anew specimen of russellosaurine mosasaur (FHSM VP-17564) from the middle Fairport Chalk Member (Collignoniceras woollgari zone, early Middle Turonian), Carlile Shale of central Kansas is among the earliest records of a derived mosasaur known from the North American Western Interior Seaway. Unequivocally the oldest recorded occurrence of a russellosaurine mosasaur from Kansas, and one of only four Kansas occurrences consisting of more than a single element, the specimen includes seven successive proximal caudal vertebrae bearing articulating hemal facets. No demonstrable characters ally the specimen to a more refined taxonomic subgroup, although the relative dimensions of the vertebral centra are significantly longer than equivalent caudal series in Platecarpus and Tylosaurus. This suggests that the tails of early russellosaurines were composed of a lesser number of longer caudal vertebrae than their successors, with less hydrodynamic adaptation from the terrestrial condition. Size of the vertebrae in relation to Platecarpus and Tylosaurus indicates a relatively large animal roughly 3.2 m in total body length, although this may be an over-estimate given the difference in vertebral dimensions as compared to more derived russellosaurines of the Niobrara Formation. The middle of the Fairport Chalk interval continues to produce a large number of vertebrate specimens despite the rarity of exposures. A pliosaurid plesiosaur skull (FHSM VP-321) is known from similar geographic and stratigraphic position as FHSM VP-17564, and the record of pliosaurs (FHSM VP-17469) continues into younger Blue Hill Shale (Prionocyclus hyatti zone, middle Middle Turonian) demonstrating with certainty that pliosaurs and early mosasaurs inhabited the same stretch of seaway for roughly one million years.

Terrestrial – Ocean environmental change in the northwestern Pacific from the glacial times to Holocene

The Mixed Water Region (MWR) between the Oyashio Current and the Kuroshio Extension and surrounding terrestrial region have been affected by the global climatic change. The sedimentary core KR02-15 PC6 collected at 40°23.8871′N, 143°29.8663′E in the MWR provides detailed records of pollen and spores and alkenone sea surface temperature (SST) during the last 15 kyr, showing that both ocean and terrestrial environments have been appreciably linked. Abundance of Picea, a proxy for terrestrial cool climate, fluctuated, coinciding with the alkenone-SST change during the interstadial period (15.0–7.7 cal kyr B.P.). Alkenone-SST increased to the modern level at 8.0 cal kyr B.P. and remained almost constant until 2.0 kyr B.P. while the terrestrial warming still continued until 4.0 cal kyr B.P. The rainfall under terrestrial warm condition increased gradually from 7.9 cal kyr B.P. and rapidly from 2.0 cal kyr B.P. Both terrestrial and marine environments cooled down during the last 2 kyr possibly due to the intensified cold Oyashio Current.

Carbon budget alteration due to landcover-landuse change in wetlands: the case of afforestation in the Lower Delta of the Paraná River marshes (Argentina)

The objective of this work was to analyse the effects on carbon budget caused by the replacement of freshwater marshes by salicaceae plantations at ecosystem and regional scales, in the Lower Delta of the Paraná River in Argentina. Biomass and net aboveground primary productivity were estimated for one of the main species planted in the delta, Salix babylonica var. sacramenta, and for the dominant species of the marshes that are most widespread in the study area, Scirpus giganteus and Schoenoplectus californicus. Soil organic carbon was also estimated. Afforestation and marshes were mapped based on the digital classification of Landsat imagery. Aboveground biomass stored by afforestation is higher than by marshes (113.4 Mg/ha vs. around 10 Mg/ha). Nevertheless, soil organic matter accumulation is 10-fold higher in the marshes. A huge amount of carbon is released into the atmosphere when marshes are converted to forest due to change from a wetland to a terrestrial condition.

Vasotocin/V2-Type Receptor/Aquaporin Axis Exists in African Lungfish Kidney but Is Functional Only in Terrestrial Condition

The vasopressin/vasotocin (VT)-V2-type receptor (V2R)-aquaporin (AQP)-2 axis plays a pivotal role in renal water reabsorption in tetrapods. It is widely thought that this axis evolved with the emergence of the tetrapods, reflecting a requirement of water retention in terrestrial environment. Here we report that lungfish, the closest living relatives of tetrapods, already possess a system similar to the VT-V2R-AQP2 axis in the kidney, but the system is functional only in the terrestrial estivating condition. We cloned a novel AQP paralogous to AQP0. The water permeability of Xenopus oocytes was increased by injection with the AQP cRNA and was further facilitated by preincubation with cAMP. In the kidney of estivating lungfish, the AQP protein was localized on the apical plasma membrane of the late distal tubule and was colocalized with basolateral V2R. By contrast, we found only little expression of the AQP mRNA and protein in the kidney of lungfish in aquatic condition. The expression levels of mRNA and protein were dramatically increased during estivation and decreased again by reacclimation of estivating lungfish to water. The AQP mRNA levels positively correlated with the VT mRNA levels in the hypothalamus, suggesting that the AQP exerts tubular antidiuretic action under control of VT. Because the tetrapod AQP2/AQP5 lineage is considered to be evolved from duplication of an AQP0 gene, the paralogous AQP0 in the lungfish probably represents ancestral molecule for tetrapod AQP2.

Bubble Behavior and Heat Transfer in Quasi-Steady Pool Boiling in Microgravity

Pool boiling of degassed FC-72 on a plane plate heater has been studied experimentally in microgravity. A quasi-steady heating method is adopted, in which the heating voltage is controlled to increase exponentially with time. Compared with terrestrial experiments, bubble behaviors are very different, and have direct effect on heat transfer. Small, primary bubbles attached on the surface seem to be able to suppress the activation of the cavities in the neighborhoods, resulting in a slow increase of the wall temperature with the heat flux. For the high subcooling, the coalesced bubble has a smooth surface and a small size. It is difficult to cover the whole heater surface, resulting in a special region of gradual transitional boiling in which nucleate boiling and local dry area can co-exist. No turning point corresponding to the transition from nucleate boiling to film boiling can be observed. On the contrary, the surface oscillation of the coalesced bubble at low subcooling may cause more activated nucleate sites, and then the surface temperature may keep constant or even fall down with the increasing heat flux. Furthermore, an abrupt transition to film boiling can also be observed. It is shown that heat transfer coefficient and CHF increase with the subcooling or pressure in microgravity, as observed in normal gravity. But the value of CHF is quite lower in microgravity, which may be only about one third of that at the similar pressure and subcooling in terrestrial condition.

A study of influence of gravity on bulk behaviour of particulate solid

This paper examines the influence of gravity on the bulk responses of a granular solid. The loading scenarios in this study include confined compression, rod penetration into a granular medium and discharging through an orifice. Similar loading and flow conditions are likely to be encountered in the stress and deformation regimes that regoliths are subjected to in extraterrestrial exploration activities including in situ resource utilisation processes. Both spherical and non-spherical particles were studied using the discrete element method (DEM). Whilst DEM is increasingly used to model granular solids, careful validations of the simulation outcomes are rather rare. Thus in addition to exploring the effect of gravity, this paper also compares DEM simulations with experiments under terrestrial condition to verify whether DEM can produce satisfactory predictions. The terrestrial experiments were conducted with great care and simulated closely using DEM. The key mechanical and geometrical properties for the particles were measured in laboratory tests for use in the DEM simulations. A series of DEM computations were then performed under reduced gravity to simulate these experiments under extraterrestrial environment. It was found that gravity has no noticeable effect on the force transmission in the confined compression case; the loading gradient in the rod penetration is linearly proportional to the gravity; the mass flow rate in silo discharge is proportional to square root of the gravity and the angle of repose increases with reducing gravity. These findings are in agreement with expectation and existing scientific evidence.

The influence of fluid shear stress on the expression of Cbfa1 in MG-63 cells cultured under different gravitational conditions

Author Purpose This study was aimed to explore the effect of flow shear stress on the expression of Cbfa1 in human osteosarcoma cells and to survey its functional alteration in simulated microgravity. After culture for 48 h in two different gravitational environments, i.e. 1 G terrestrial gravitational condition and simulated microgravity condition, human osteosarcoma cells (MG-63) were treated with 0.5 or 1.5 Pa fluid shear stress (FSS) in a flow chamber for 15, 30, and 60 min, respectively. The total RNA in cells was isolated. RT-PCR analysis was made to examine the gene expression of Cbfa1. The total protein of cells was extracted and the expression of Cbfa1 protein was detected by means of Western blotting. Results MG-63 cells cultured in 1 G condition reacted to FSS treatment with an enhanced expression of Cbfa1. Compared with no-FSS control group, Cbfa1 mRNA expression increased significantly at 30 and 60 min with the treatment of FSS ( P P P P P P Conclusions FSS can significantly increase the gene and protein expression of Cbfa1 in human osteosarcoma cells. And this inducible function of FSS was adversely affected by simulated microgravity.

The nonmarine environment of Quaternary foraminifers in Yanghuzhuang, China: Evidence from boron and strontium isotopes

The concentrations and isotopic compositions of boron and strontium of Quaternary foraminifers and bivalve fossils collected in the Yanghuzhuang section of Yanqing, Beijing and of modern gastropods living in the Guishui River and of river water were measured. The concentrations and isotopic compositions of Quaternary foraminifers and bivalve fossils differed from those of modern marine foraminifers and were similar to those of modern terrestrial gastropods from the Guishui River. These results indicate that early Quaternary foraminifers in the Yanghuzhuang section inhabited a nonmarine environment and that these foraminifers were not the result of a transgression or sea flooding. The foraminifers were not special halobios and can survive in the terrestrial condition that resembled those of the ocean.

Big concepts, small N

Big concepts, small N

Gravity-Induced Convection during Directional Solidification of Hypermonotectic Alloys

A two-phase volume-averaging model developed for the simulation of the dynamic decomposition and solidification of hypermonotectic alloys was used to study the occurrence of convection phenomena during directional solidification of a hypermonotectic alloy (Al-10 wt.%Bi) under terrestrial condition. The model accounts for nucleation and growth of secondary phase droplets, Marangoni and Stokes forces, solute partitioning, heat release due to decomposition and solidification. It is shown that the appearance and growth of secondary droplets is accompanied with a continuous downwards motion of droplets, which rapidly becomes unstable. After relaxation of this dynamic motion the advancing solidification front freezes in the resulting non-uniform droplet distribution.

Predicting the optical properties of the West Florida Shelf: resolving the potential impacts of a terrestrial boundary condition on the distribution of colored dissolved and particulate matter

Predicting the distribution of Inherent Optical Properties (IOPs) in the water column requires predicting the physical, chemical, biological, and optical interactions in a common framework that facilitates feedback responses. This work focuses on the development of ecological and optical interaction equations embedded in a 2D hindcast model of the shallow water optical properties on the West Florida Shelf (WFS) during late summer/fall of 1998. This 2D simulation of the WFS includes one case with a Loop Current intrusion above the 40-m isobath and one with the Loop Current intrusion in addition to a periodic terrestrial nutrient supply below the 10-m isobath. The ecological and optical interaction equations are an expansion of a previously developed model for open ocean conditions (Bissett, W.P., Carder, K.L., Walsh, J.J., Dieterle, D.A., 1999a. Carbon cycling in the upper waters of the Sargasso Sea: II. Numerical simulation of apparent and inherent optical properties. Deep-Sea Research, Part I: Oceanographic Research Papers, 46 (2), 271–317; Bissett, W.P., Walsh, J.J., Dieterle, D.A., Carder, K.L., 1999b. Carbon cycling in the upperwaters of the Sargasso Sea: I. Numerical simulation of differential carbon and nitrogen fluxes. Deep-Sea Research, Part I: Oceanographic Research Papers, 46 (2), 205–269). The expansion includes an increase in the number of elemental pools to include silica, phosphorus, and iron, an increase in the number of phytoplankton functional groups, and a redevelopment of the Dissolved Organic Matter (DOM) and Colored Dissolved Organic Matter (CDOM) interaction equations. It was determined from this simulation that while the Loop Current alone was able to predict the water column conditions present during the summer, the Loop Current alone was not enough to simulate the magnitude of optical constituents present in the fall of 1998 when compared to satellite imagery. Simulating terrestrial inorganic and organic nutrients and CDOM pulses coinciding with significant meteorological events and high freshwater pulses released from the major rivers feeding the WFS were required to accurately predict the distribution and scale of the inherent optical properties at the surface during the fall months. Modeling the in situ light field for phytoplankton growth and community competition requires addressing the CDOM optical constituent explicitly. The majority of the annually modeled CDOM on WFS was created via in situ production; however, it was also rapidly removed via advection and photochemical destruction. A pulse of terrestrial nutrient and organic color was required to simulate the dramatic changes in surface color seen in satellite imagery on the WFS. The dynamics of the biogeochemical portion of the simulation demonstrate the importance of nonstoichiometric supplies of terrestrial nutrients on the WFS to the prediction of nutrient and CDOM fluxes.

An Evaluation of the Individual Components and Accuracies Associated with the Determination of Impervious Area

The percentage of impervious surface area in a watershed has been widely recognized as a key indicator of terrestrial and aquatic ecosystem condition. Although the use of the impervious indicator is widespread, there is currently no consistent or mutually accepted method of computing impervious area and the approach of various commonly used techniques varies widely. Further, we do not have reliable information on the components of impervious surfaces, which would be critical in any future planning attempts to remediate problems associated with impervious surface coverage. In cooperation with the USGS Geographic Analysis and Monitoring Program (GAM) and The National Map, and the EPA Landscape Ecology Program, this collaborative research project utilized very high resolution imagery and GIS techniques to map and quantify the individual components of total impervious area in six urban/suburban watersheds in different parts of the United States. These data were served as ground reference, or "truth," for the evaluation for four techniques used to compute impervious area. The results show some important aspects about the component make-up of impervious cover and the variability of methods commonly used to compile this critical emerging indicator of ecosystem condition.

Navigating in a virtual three-dimensional maze: how do egocentric and allocentric reference frames interact?

Spatial navigation in the presence of gravity restricts one's displacement to two-dimensional (2D) planes. Therefore, self-motion only includes translations and yaw rotations. In contrast, in weightlessness, one can translate and turn in any direction. In the first experiment, we compared the ability to memorize a virtual three-dimensional (3D) maze after passive exploration in three self-motion conditions, each using a different set of rotations for turning. Subjects indicated which pathway they traversed among four successive corridors presented from an outside perspective. Results showed that exploring in the terrestrial condition (including only yaw rotations, the viewer's virtual body remaining upright) allowed better recognition of the corridor than in the weightless condition (which included pitch and yaw rotations according to the turns), particularly for more complex 3D structures. The more frequently the viewer-defined (egocentric) and the global environment (allocentric) verticals were aligned during exploration, the more easily subjects could memorize the 3D maze, suggesting that simplifying the relationship between the egocentric and allocentric reference frames facilitates spatial updating. Nevertheless, with practice, performance in the weightless condition improved whereas in the natural terrestrial condition performance remained at its initial maximum, indicating that the cognitive processes involved were innate for this particular condition. The second experiment revealed that single rotations in the terrestrial condition must be performed around the body axis in order to obtain optimal spatial updating performance, and that the latter is independent of the conflict with gravity that might favor this condition when one is actually upright. This suggests that although humans can memorize 3D-structured environments their innate neurocognitive functions appear to be specialized for natural 2D navigation.