Dielectric and Dilatometric Studies of Glass Transitions in Thin Polymer Films

Dielectric relaxation and thermal expansion spectroscopy were made for thin polystyrene films in order to measure the temperature $T_{\alpha}$ corresponding to the peak in the loss component of susceptibility due to the $\alpha$-process and the $\alpha$-relaxation time $\tau$ as functions of film thickness $d$. While the glass transition temperature $T_{\rm g}$ decreases with decreasing film thickness, $T_{\alpha}$ and $\tau$ were found to remain almost constant for $d>d_{\rm c}$ and decrease drastically for $d<d_{\rm c}$ for high temperatures. Here, $d_{\rm c}$ is a critical thickness. Near the glass transition temperature, the thickness dependence of $T_{\alpha}$ and $\tau$ is more prominent. The relation between the fragility index and non-exponentiallity is discussed for thin films of polystyrene.Comment: 4 pages, 5 figure

Fracture energy of gels

To clarify effects of crack speed and cross-link density on fracture energy of acrylamide gels, we evaluated the roughness of the fracture surface and measured the fracture energy taking into account the roughness. The fracture energy increases linearly with crack speed $V$ in a fast crack speed region, and the increasing rate of fracture energy with $V$ decreases with increasing cross link density in the gels. In a slow crack speed region the fracture energy depends on crack speed more strongly than in the fast crack speed region. This indicates that a qualitative change exists in fracture process of the gels.Comment: 7 pages, 8 figures. Some errors in the first version have been correcte

Simple Methods for Estimating Outflow Salinity from Inflow and Reservoir Storage

Reservoir storage reduces fluctuation in streamflow salinity, as inflow blends with stored water. This process is directly relevant to reservoir management, yet the methods for predicting outflow salinity from inflow and storage data are not adequately addressed. This study examined three simple methods for estimating outflow salinity on a monthly time step. The first method applies when inflow approximately equals outflow. The second method is applicable to changing reservoir storage. The third method utilizes a two-layer model in which evaporative concentration is assumed to occur in the top layer. The third method requires the full account of the water balance, including evaporation and percolation losses. All three methods require reservoir storage blend with inflow in a stepwise manner. Outflow salinity was then computed monthly as a moving average. These methods were applied to high and low storage periods up to two years at three large reservoirs (Elephant Butte, Amistad, and Falcon) located along the Rio Grande. All of the equations tested provided good estimates of outflow salinity with the standard errors of estimate ranging from 5 to 10%. When a matching factor (accounting for ungauged inflow and water levels) was used in the first or the second method, they provided the estimate of monthly outflow salinity just as accurately as did the two-layer model. The accuracy of prediction, especially by the third method, can be improved if the initial reservoir salt storage is assessed with greater accuracy. Although the third method is more descriptive, the first two methods are also useful when detailed water balance data are not available

Chemical zoning of olivines in the Yamato-791717 CO3 chondrite

The chemical zoning profiles of olivines in the Yamato (Y)-791717 CO3 chondrite have been analyzed in order to explore its thermal history. Two alternative models were applied to distinguish igneous processes from metamorphic features; they are fractional crystallization and diffusive modification of primary composition. It was clarified that chemical zoning of olivines in Y-791717 has been formed by a diffusion process, suggesting that this meteorite has been thermally metamorphosed. Thermal metamorphism of Y-791717 we have shown is consistent with that proposed on the basis of thermoluminescence investigation. A diffusion model also allows us to examine its thermal history in a quantitative way. Using a diffusion model, we have most successfully reproduced measured zoning profiles in isolated and chondrule olivine grains from Y-791717 in the temperature range 800-300℃. The temperature range is broadly consistent with the previously proposed peak metamorphic temperatures for CO3 chondrites

Uniform Cyclic Group Factorizations of Finite Groups

In this paper, we introduce a kind of decomposition of a finite group called a uniform group factorization, as a generalization of exact factorizations of a finite group. A group $G$ is said to admit a uniform group factorization if there exist subgroups $H_1, H_2, \ldots, H_k$ such that $G = H_1 H_2 \cdots H_k$ and the number of ways to represent any element $g \in G$ as $g = h_1 h_2 \cdots h_k$ ($h_i \in H_i$) does not depend on the choice of $g$. Moreover, a uniform group factorization consisting of cyclic subgroups is called a uniform cyclic group factorization. First, we show that any finite solvable group admits a uniform cyclic group factorization. Second, we show that whether all finite groups admit uniform cyclic group factorizations or not is equivalent to whether all finite simple groups admit uniform group factorizations or not. Lastly, we give some concrete examples of such factorizations.Comment: 10 pages. To appear in Communications in Algebr

Fracture behavior of single crystal silicon with thermal oxide layer

This paper reports on the effect of oxidation on fracture behavior of single crystal silicon (SCS). SCS specimens were fabricated from (1. 0. 0) silicon-on-insulator wafer with 5-μm-thick device layer and oxide layer were thermally grown. Quasi-static tensile testing of as-fabricated, oxidized and oxidized layer removed specimens was performed. The fracture origin location transited from the surface to silicon/oxide interface and inside of silicon. The transition may be caused by surface smoothing, thickening oxide layer and formation of oxide precipitation defects in silicon during oxidation. The radius of the oxide precipitation defects was estimated, which is well agreed with the fracture-initiating crack sizes

Mehr Gesundheit und sozialer Zusammenhalt durch Bildung: Politikempfehlungen und zukünftige Prioritäten der OECD

Bei den nachstehenden Ausführungen handelt es sich um die Übersetzung der Schlussfolgerungen des Berichts "Improving Health and Social Cohesion through Education" in gekürzter Fassung. Die Daten wurden im Rahmen des OECD-Projekts "Social Outcomes of Learning" (SOL) generiert. Im Zentrum steht die These, dass Personen mit höherem Bildungsstand häufig länger leben, seltener straffällig werden und sich stärker in der Gesellschaft engagieren als Personen mit niedrigerem Bildungsstand. Der OECD-Bericht fragt nach den entsprechend empirischen Erkenntnissen und rekapituliert die Befunde auf der Grundlage der rasant wachsenden Literatur zum Thema "Benefits". Auf dieser Basis werden Politikempfehlungen formuliert und weitere Forschungsbedarfe aufgezeigt

The Specific Practice of School Based Curriculum Development - Organizational Practice of Japanese language learning through the Interpretation of the School Educational Aims -

本研究の目的は，学校カリキュラムの開発において，「目指す子ども像」の共有と，その姿の実現に向けた取り組みの具体的な展開，実践の詳細を検討することにある。具体的には，カリキュラム開発に携わるリーダーシップと意思決定のあり方，そしてそれが機能した（機能しつつある）開発の過程についての事例として，岡山大学教育学部附属小学校国語部の取り組みを検討した。検討を通じて明らかになったことは，「目指す子ども像」をもとに授業自体を解釈し直し，授業の意味を探ることを通じて，授業者自身にも「目指す子ども像」を具現化した授業がイメージできるようになり，学校全体を通じた組織的な取り組みとなる可能性があるということである。さらに，こうした取り組みを行う中で，実践的リーダーは，解釈のモデルを示したり，やりとりをする中で別の解釈を引き出したりすることや，解釈自体を修正したりすることが重要となることが明らかになった