A Study on the Mechanism of Consolidation

Reducing the linear Biot's equations into a single governing equation, the mechanism ofmulti-dimensional consolidation is considered by means of a variational principle. Particularly, the investigation is made for the geometrical meaning of the linear relation between the distribution of excess pore water pressure and that of deformation, which is obtained by observing the consolidation process from the final steady state. As the results of the present study, we can conclude that (1) Biot's equations of consolidation are reduced into a single governing equation with the excess pore water pressure as the only unknown function, if we choose the final steady state as the reference, (2) the consolidation process is interpreted as a series of minimum norm problems in a metric vector space, i.e., the Function Space, and (3) the equilibrium condition of consolidation is equivalent to determining a point in some subset which has the shortest distance from the origin of the Function Space

Eigenvalue Problem of Consolidation

Following the preceding paper, the discussion in this paper will be that the governing equation of the multi-dimensional consolidation expressed in terms of the excess pore water pressure alone, can be treated analytically through the eigenvalue problem similar to that of the one-dimensional case. Especially, we will emphasize the importance of the first eigenvalue for the practical application of this theory. The main conclusions of this study are : (1) We can find a set of eigenvalues and eigenfunctions of the multi-dimensional consolidation quite similar to those derived from Terzaghi's one-dimensional equation. (2) The magnitude of the eigenvalue is proportional to the dissipative energy due to the seepage flow. (3) The degree of consolidation is mostly determined by the first eigenvalue and therefore it can be used to estimate the effectiveness of the sand drain as an application

Sea-Ice Production in Antarctic Coastal Polynyas Estimated From AMSR2 Data and Its Validation Using AMSR-E and SSM/I-SSMIS Data

Antarctic coastal polynyas are very high sea-ice production areas. The resultant large amount of brine rejection leads to the formation of dense water. The dense water forms Antarctic bottom water, which is the densest water in the global overturning circulation and a key player in climate change as a significant sink for heat and carbon dioxide. In this study, an algorithm was developed that uses Advanced Microwave Scanning Radiometer 2 (AMSR2) data (2012-present) to detect polynya area and estimates thin ice thickness by a method similar to that used to develop the algorithm for Advanced Microwave Scanning Radiometer for EOS (AMSR-E) data. Landfast sea-ice areas were also detected using AMSR2 data. Ice production in the polynyas was estimated by a heat flux calculation using AMSR2 sea-ice data. In four major polynyas, AMSR2 ice production was compared with AMSR-E (2003-2011) ice production through comparison of them with Special Sensor Microwave Imager (SSM/I) and Special Sensor Microwave Imager/Sounder (SSMIS) ice production. The comparison confirmed that the ice production from AMSR-E/2 data, which have higher spatial resolution than SSM/I-SSMIS data, can be used to analyze time series covering more than 10 years. For example, maps of annual ice production based on AMSR-E/2 data revealed detailed changes of the Mertz Polynya, where the ice production decreased significantly after the Mertz Glacier Tongue calving in 2010. Continuous monitoring of the coastal polynyas by the AMSR series sensors is essential for climate-change-related analyses in the Antarctic Ocean

Evaluation of Carotid Arterial Intima-Media Thickness (IMT) and Its Relation to Clinical Parameters in Japanese Children

The aim of this study was to evaluate the carotid arterial intima-media thickness (IMT) and its relation to clinical parameters in Japanese children. Fifty-two healthy children (39 boys and 13 girls), aged 6-14 years, were enrolled in this cross-sectional investigation study. IMT of the common carotid artery was determined using ultrasonography. We also investigated anthropometric parameters, blood pressure (BP), lifestyles and blood examinations. The mean value of IMT was 0.4±0.1mm, which was lower than the normal value (1.0mm) in adults. IMT was positively correlated with age (r＝0.340) and height (r＝0.346) in boys, while it was positively correlated with body mass index (BMI) (r＝0.584) and diastolic BP (DBP) (r＝0.563) in girls. In addition, IMT was associated with sleeping hours and hours of watching television (TV) by using stepwise regression analysis. In conclusion, IMT increased with aging, and it was linked to some clinical parameters of atherosclerosis and lifestyles in children. Therefore, this reference data will be helpful for future assessment of age-related change in Japanese children in clinical practice, and IMT might be a good predictor of atherosclerosis in Japanese children

Seismic Response Analysis of Offshore Seabed with Depth-Proportional Shear Modulus

Referring to the results of the PS-logging performed at the boring site of the 150 m-deep seabed in Osaka Bay, it is found that there exists a relationship between the celerity of the transversal wave, vₛ (m/s), and the depth of soil layers, z (m) , as vₛ= 30z⁰.5. Other information obtained from the soil exploration also indicates that the seabed is almost normally consolidated at the site. These data show that the shear modulus increases proportionally with depth. In this paper, the characteristic function of such a ground is deduced by solving the fundamental differential equation, and the procedure of seismic response analysis is described. By the numerical calculation for a modeled seabed subjected to a simulated irregular seismic excitation at the base ground, it is known that, at the mudline, all responses reach their maximum values. In particular, the acceleration response attains as high as 4.7 times the input ground motion

The investigation into the Ice shelf-Ocean Interaction of East Antarctica with special focusing on the Ocean Circulation

The Tenth Symposium on Polar Science/Special session: [S] Future plan of Antarctic research: Towards phase X of the Japanese Antarctic Research Project (2022-2028) and beyond, Tue. 3 Dec. / 2F Auditorium, National Institute of Polar Researc