TIDICS—Control of tidal residual circulation and tidal exchange in a channel-basin system

A self-excited oscillation of tidal flow occurs in a tidal channel-basin system with a narrow and high speed inflowing tidal jet. The mechanism of this oscillation was examined through hydraulic experiments. Results show that the oscillation is caused by alternation in the strength of asymmetric residual circulation caused by a biased supply of vorticity by asymmetric tidal vortex pairs, and that the mechanism of alternation also depends on negative feed-back between the residual circulation and the vorticity supply.The unstable state of the flow suggested the possibility of controlling the tidal current and tidal exchange in the channel-basin system and this was confirmed experimentally. Under fixed tidal conditions and with fixed basin dimensions, the tidal residual circulation was controlled to form two strong clockwise and anticlockwise circulations or a single circulation by changing the shape of the bay entrance.     

Asteroids approaching the Earth from directions around the Sun

We have estimated close asteroid encounters with the Earth by numerical integrations of a system with the Sun, 9 planets, and 188 near-earth-asteroids during the period 1994–4600. Asteroids approach the Earth from directions within 30? around the Sun in more than 20% of encounters with the closest distance less than 0.01 AU. Since ground-based observations cannot detect these objects, we should develop space-borne and/or lunar observatories in a short time to allow enough warning time before a catastrophic collision.     

Reliability analysis of shallow foundations in reference to design codes development

In this study, FORM analysis is carried out for shallow foundation of a typical building in order to evaluate relative magnitude of uncertainties involved in the force and the resistance sides. The distinguished feature of this study is to take into account the uncertainty of the earthquake force as much as possible. Tthis is because, the seismic design dominates major part of structural design in Japan, and without referring to this problem, no useful information of practical value is gained. The results of the FORM analysis exhibited the reliability index values between 2.0 to 3.5, which is considered to be in a reasonable range. Since the 50 year maximum earthquake force is considered in the reliability calculation, calculated reliability index values are for the period of 50 years. The sensitivity factor obtained in a case more realistic ground variability is taken into account exhibited values not very different from those obtained in the upper structures.     

Formation of stars by implosion of a gas cloud

In the standard Friedmann cosmology the black-body radiation spectrum is usually taken (without explicit proof as far as we know) to have the same familiarT ⁴-form that it has in a flat space. With explicit use of the equation of motion of a quantized massless field propagating in a curved background Robertson-Walker metric we show (for the readily tractable scalar field case) that the assumption is in fact true for an open Universe. For a closed Universe, we find that there is an in principle modification to theT ⁴-law. Unfortunately, the correction turns out to be too small to be experimentally detectable. In passing, we also obtain a simple derivation for the cosmological red shift of frequencies.     

GMS proton flux observation during February 1978

It is suggested that the drop out of the 1.2–4 MeV proton flux, observed by the geostationary satellite GMS, was due to the Earthward shift of the particle boundary in all local time. The particle boundary motions are associated with substorm activities.     

http://www.sciencedirect.com/science/article/pii/S167498711200062X

This paper focuses on the formation mechanism of fractures induced by excavation of a gallery in soft sedimentary rocks in the Horonobe area of Japan.Detailed fracture mapping of the gallery indicates that the fractures consist of both pre-existing shear fractures and excavation damaged zone(EDZ) fractures. EDZ fractures correspond to weak planes associated with bedding planes or transgranular cracks.The EDZ fractures terminate against pre-existing shear fractures.Therefore,even for excavations in soft sedimentary rocks,formation of the EDZ fractures are controlled by pre-existing fractures and earlier weak planes.     

Three-year assessment of particulate organic carbon fluxes in Amundsen Gulf (Beaufort Sea): Satellite observations and sediment trap measurements

Surface concentrations and vertical fluxes of particulate organic carbon (POC) were assessed in the Amundsen Gulf (southeastern Beaufort Sea, Arctic Ocean) over the years 2004 to 2006 by using ocean color remote-sensing imagery and sequential sediment traps moored over the ca. 400 m isobath. Environmental conditions (sea ice, wind) and oceanographic variables (temperature, salinity, fluorescence and currents) were investigated to explain the variability of POC data. Annual downward POC fluxes in 2004, 2005 and 2006 cumulated, respectively, to 3.3, 4.2 and 6.0 g C m^?2 yr^?1 at ～100 m depth, and to 1.3, 2.2 and 3.3 g C m^?2 yr^?1 at ～210 m depth. The fraction of settling POC attributable to autochthonous processes occurring at or next to ice break-up was estimated to be 75–84% of the 100 m annual fluxes and to be 61–75% of the 210 m fluxes. Over the three ice-reduced seasons, distinct scenarios between ice conditions, surface POC pools and vertical POC export at 100 m were identified: (1) in 2004, despite a normal ice break-up, a weak primary production was measured and low vertical fluxes were collected as old ice moved across the region; (2) in 2005, a lengthened ice-free period allowed an extended season of surface POC production near-shore, while an intermediate increase of vertical fluxes was recorded offshore; and (3) in 2006, a late ice melt gave rise to a pulsed ice edge bloom and to large vertical fluxes also associated with extra ice-flushed material. Linear regressions of vertical POC fluxes against satellite-derived surface POC concentrations suggested that the pelagic POC retention in the upper 100 m of the Amundsen Gulf ranged from ca. 70% to 90% depending on the timing of ice cover melt. Regardless of the inter-annual variability, the estimated fraction of the surface POC reservoir reaching the 210 m water depth was reduced to ～5%. Therefore, as the Arctic Ocean warms up, our results support the expectation that the increasing extent of the seasonal ice zone will promote the POC pathways that benefit pelagic webs rather than benthic communities.     

The potential of intra-regional supply and demand of agricultural products in an urban fringe area: A case study of the Kanto Plain,Japan

Geografisk Tidsskrift—Danish Journal of Geography 109(2):147–159, 2009

The increasingly global reach of industrial agricultural production has progressively distanced consumers and producers. Not surprisingly, opposition to the global food system commonly seeks to re-localize agriculture by cutting the distance between agricultural production and consumption. Analysis of potential foodsheds can provide an important basis upon which to recover local systems of production and consumption. Here, we examine the potential for municipal and micro-level foodsheds in the greater Tokyo mega-region. Similar to other large cities in Asia, the urban fringe of Tokyo has extensive areas of mixed urban and agricultural land-uses which are often seen as problematic, but which may have many merits from the standpoint of sustainable foodsheds. Indeed, our results indicate that many areas on the urban fringe of the Tokyo mega-region bear potential to meet demand for both rice and vegetables within their borders. Moreover, many people could meet their food needs within a short distance of their residence. These results demonstrate the need to examine the potential for micro-level foodsheds on the urban fringe.