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1

Evaluation of reliability of perioral muscle pressure measurements using a newly developed device with a lip piece

Takahashi M., Koide K., Suzuki H., Satoh Y., Iwasaki S.-I.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 1

145--153

EN

Purpose: We examined the reliability of measurements using a newly developed perioral muscle pressure measuring device with a lip piece in healthy adults. Methods: Subjects were 40 healthy men (25.8 years) with normal stomatognathic function. Perioral muscle pressure measuring device with a lip piece was used to measure upper lip, lower lip and tongue pressure, and a balloon-based measurement device was used to measure tongue and cheek pressure. Each measurement was taken twice with a 1-min interval between the two measurements. We determined intra-rater reliability by using the intra-class correlation coefficient as a test of relative reliability. As a test of absolute reliability, Bland–Altman analysis was used to assess systematic bias and the 95% confidence interval of the minimal detectable change was calculated. Additionally, the coefficient of variation was calculated. The Spearman–Brown formula was calculated the number of measurements needed to achieve a confidence coefficient ≥0.9. Each set of measurements was followed by a second set that were taken 1 week later. Results: All measurements showed high values of intra-class correlation coefficient. Upper lip, tongue, and cheek pressure can be determined based on a single measurement, while lower lip pressure requires averaging twice. No systematic bias was observed. The coefficients of variation of measurements were almost the same between the two devices. Conclusion: Measurements were highly reliable regardless of the type of perioral muscles. Our findings suggest that the method described in this study is useful as a quantitative chair side method for examining perioral muscle pressure.

2

Evolutes and involutes of frontals in the euclidean plane

Fukunaga T., Takahashi M.

Demonstratio Mathematica

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2015

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Vol. 48, nr 2

147--166

EN

We have already defined the evolutes and the involutes of fronts without inflection points. For regular curves or fronts, we can not define the evolutes at inflection points. On the other hand, the involutes can be defined at inflection points. In this case, the involute is not a front but a frontal at inflection points. We define evolutes of frontals under conditions. The definition is a generalisation of both evolutes of regular curves and of fronts. By using relationship between evolutes and involutes of frontals, we give an existence condition of the evolute with inflection points. We also give properties of evolutes and involutes of frontals.

3

Permeability and deformation characteristics of Shirahama sandstone under a general stress state

Takahashi M.

Archives of Mining Sciences

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2007

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Vol. 52, no 3

355-369

EN

In this paper, results of experimental studies on the dependence between the permeability and the deformation mode of Shirahama sandstone subjected to an axi-symmetric triaxial compressive stress state and a true triaxial compressive stress state are presented. Under conventional triaxial compression conditions, in the brittle faulting regime, permeability decreases with increasing axial strain until the onset of dilatancy when it increases significantly with ongoing axial strain. For specimens subjected to effective confining pressures of less than 10 MPa, the final permeability is greater than the initial value; by contrast, in both the brittle-ductile transition and ductile regimes the permeability following the onset of dilatancy increases only slightly. Deformed and failed specimens show a final value of permeability that is lower than the initial pre-deformation value. Whether shear displacement exerts a significant control on the permeability of faults in rock masses is a major topic of concern in the fields of engineering and earth sciences. To c1arify the relation between permeability and the internal structure of a rock sample, the three principal strains and permeability along the intermediate principal stress direction were measured during deformation as a function of the three principal stresses. The specimen was deformed under a true triaxial compression stress state in which the intermediate principal stress was different to the minimum and maximum principal stress.

PL

W artykule przedstawione są wyniki badań nad zależnością pomiędzy przepuszczalnością a charakterem deformowania się próbek piaskowca Shirahama w warunkach osiowo-symetrycznego i asymetrycznego (prawdziwie trójosiowego) stanu naprężeń ściskających. Mioceński piaskowiec Shirahama pochodzi z półwyspu Kii na wyspie Honsiu w środkowej Japonii. Jest to skała zbudowana głównie z ziaren kwarcu (44,23%) i okruchów skał (46,41%). Wielkość ziaren kwarcu wynosi średnio ok. 0,15 mm. W piaskowcu dominują pustki o wielkości l [...]; całkowita porowatość skały wynosi ok. 13% (rys. 1). Badania nad przepuszczalnością piaskowca Shirahama w warunkach konwencjonalnego trójosiowego ściskania przy różnych ciśnieniach okólnych zostały przeprowadzone za pomocą aparatury przedstawionej na rysunku 2. Badane były próbki walcowe o średnicy 30 mm i wysokości 60 mm. Przy niskich ciśnieniach okólnych próbki skały doznawały dylatancji i pękały ścięciowo w stadium pokrytycznym. W warunkach wysokich ciśnień skała zachowywała się ciągliwie, a odkształcenie objętościowe i zmiany objętości porów wskazywały na stałą, trwałą kompakcję materiału skalnego podczas próby na ściskanie (rys. 4). Należy jednak dodać, że wyniki pomiarów porowatości całkowitej wykonanych za pomocą porozymetru rtęciowego pokazały, że porowatość rośnie ze wzrostem ciśnienia okólnego (rys. 5). Odkrycie to potwierdzone zostało pomiarami powierzchni właściwej przestrzeni porowej skały wykonanymi za pomocą metody BET (rys. 6). Wynika stąd, że im większa głębokość w górotworze, tym większa porowatość towarzyszy odkształceniom niesprężystym. A więc w warunkach dużych ciśnień na dużych głębokościach i wysokiego naprężenia dewiatorowego skały mają wysoką zdolność do magazynowania płynów (zdolność zbiornikową). Próby na tzw. prawdziwe trójosiowe ściskanie próbek piaskowca Shirahama przeprowadzono w celu zbadania przepuszczalności materiału skalnego w kierunku równoległym do pośredniego naprężenia głównego. W aparacie trójosiowym Koidego i Takahashiego, którego fragment pokazany jest na rysunku 7, badano próbki prostopadłościenne o wymiarach 34 mm x 34 mm x 70 mm. Przepuszczalność mierzona była w sposób ciągły podczas całego procesu deformowania się próbki skalnej: od stadium odkształceń sprężystych, poprzez stadium odkształceń plastycznych, aż do stadium poślizgu na ściankach ostatecznego makropęknięcia. W wyniku przeprowadzonych badań stwierdzono, że przemieszczeniom stycznym wzdłuż płaszczymy makropęknięcia ścięciowego (uskoku) w próbce nie towarzyszą istotne zmiany przepuszczalności (rys. 8 i 9).

4

Sur le comportement dilatant d'un gres dans les conditions de compression triaxiale vraie

Kwaśniewski M., Takahashi M., Li X.

Studia Geotechnica et Mechanica

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2005

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Vol. 27, nr 1-2

117-124

FR

Il résulte des essais triaxiaux que la pression de confinement inhibe fortement le processus de dilatance dans les grès à grain moyen testé dans les conditions de compression triaxiale conventionnelle. Le phénomène de dilatance était également limité de façon significative par la contrainte principale intermédiaire. Alors que l’importante déformation dilatante correspondait à la contrainte différentielle ultime avec les faibles contraintes principales intermédiaires, dans les conditions de fortes contraintes intermédiaires, le matériau rocheux subissait l’endommagement de façon beaucoup moins importante.

5

Structure analysis and local magnetic parameters of magnetoresistance tunnel junctions

Kim C., Kim C. O., Hu Y., Kanak J., Stobiecki T., Ogata S., Tsunoda M., Takahashi M.

Materials Science

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2003

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Vol. 21, No. 1

9-23

EN

The Magnetoresistance Tunnel Junctions (MTJ) were deposited by DC magnetron sputtering method in the following layer sequence: Ta(50A)/Cu(100A)/Ta(50A)/Ni80Fe20(20A)/Cu(50A)/Mn75Ir25(100A)/Co70Fe30(25A)/Al-O/Co70Fe30(25A)/Ni80Fe20(t) /Ta(50A)/, with t = 0A, 100A and 1000A. X-ray diffraction analysis revealed that highly oriented fcc-(111) of IrMn3, Cu, Ni80Fe20 and Co70Fe30 crystal planes are stacked parallel to the substrate plane. The improvement of (111) texture and crystallinity was observed after annealing. The tunneling magnetoresistance ratio of patterned junction with electrode layer of Ni80Fe20 (t = 1000A), deposited on the free layer of Co70Fe30 (25A) exceeds 40% at room temperature after annealing at 200°C in magnetic field 1kOe. The local hysteresis loops were measured using the magneto-optical Kerr effect system. The relatively irregular variations of coercive force Hc and unidirectional anisotropy field Hua in as-deposited sample are revealed. After 200°C annealing Hc decreases but Hua increases with smooth local variations. Two-dimensional plots of Hc and Hua show the symmetric saddle shapes with their axes aligned with the pinned layer. The distribution of surface roughness is symmetric with respect to the center of MTJ. Correlation between surface roughness and the variation of Hua suggests that the Hua variation of the free layer is well described by dipole interactions in the form of socalled Néel "orange peel" coupling.

6

Probabilistic methods for estimating the long-term spatial characteristics of monogenetic volcanoes in Japan

Martin A., Takahashi M., Umeda K., Yusa Y.

Acta Geophysica Polonica

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2003

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Vol. 51, nr 3

271-289

EN

The long-term future spatial distribution of monogenetic volcanoes is much more difficult to estimate than for polygenetic volcanoes because the location of the next eruption forming a new edifice is different. Current knowledge of the complex geological factors and natural processes controlling the locations of monogenetic volcanoes is insufficient to estimate future spatial and temporal patterns. This has been achieved instead through the development and application of the probabilistic and statistical approach, especially during the last two decades. In Japan, a lot research has been focused on the construction of volcanic hazard maps in the event of a volcanic eruption for natural disaster management - the consequences of volcanism - but not the probability of new volcanic edifices forming within or nearby volcanic fields for geological disposal. In this paper, the development of the probabilistic approach is described and the results of probabilistic case studies on the Higashi-Izu (59 vents) and the Kannabe -Oginosen (38 vents) Monogenetic Volcano Groups In Japan are reported using: (1) a spatial model; and (2) a spatio-temporal nearest-neighbor model. The accuracy of each model is also examined.