シンドウネンショウノキソテキケンキュウ

京都大学0048新制・論文博士工学博士乙第1730号論工博第398号新制||工||179(附属図書館)2700UT51-46-B115(主査)教授 佐藤 俊, 教授 大東 俊一, 教授 神元 五郎学位規則第5条第2項該当Kyoto UniversityDA

A Simple Theory for Heat and Mass Transfer in a Compressible Tubulent Boundary Layer on a Flat Plate with Foreign Gas Transpiration

As a preparatory study of ablation cooling or transpiration of combustible gases into a boundary layer, a simple theory has been developed for the calculation of skin-friction, heat transfer and mass transfer coefficients of a flat plate turbulent boundary layer transpired with foreign gas. For this purpose, the theory previously developed by the author has been extended. The extension was made in two points, namely that the assumption on the Prandtl and Schmidt number with their values being unity was removed, and that a compressibility of fluid was successfully taken into account. The extended theory is also similar to those by Rubesin and Pappas, and by Denison. However, an improvement has been made in that any number of chemical species is allowed to compose the fluid. This is very neccessary in order to apply the theory to the problems mentioned above. The results abtained are in fairly good agreement with the available experimental results. Also, the computational time is believed to be much shorter than that needed in similar numerical colculations by Landis and Mills

Numerical Study of Confined Jets : I. Prediction of Flow Pattern and Turbulence Quantities with a Two-equation Model of Turbulence

This paper presents numerical predictions of the flow pattern and the turbulence quantities in confined jets which have almost no recirculating flow. Basic equations relevant for this problem are an elliptic type of differential equations. The turbulence model employed is a two-equation model in which an eddy viscosity introduced is given from the local turbulent kinetic energy and its dissipation rate. The calculated results of the mean flow pattern are in fairly good agreement with the experimental counterparts, and the observable discrepancy is discussed in relation with the turbulence quantities. Additionally, a few comments are presented for future study of a better turbulence model

Studies on Thin Liquid Film of Annular-mist Two-phase Flow : I. Wave Characteristics and Heat Transfer

This paper presents measurements both of the heat transfer coefficient and wave characteristics of liquid film in an annular-mist two-phase two component flow. The liquid film surface waves were obtained by a two-wire conductance method. Comparing the increasing tendency of the heat transfer coefficient on the liquid flow rate with that of the wave height, the enhancement of the heat transfer coefficient is found to correspond to the onset of disturbance waves. Additionally, the relationship between the wave velocity and its height was obtained, using two sets ofconductance probes. The velocity of ripple increases with its height, while the velocity of disturbance wave increases with apparent gas phase velocity, regardless of its height

Study on Turbulent Boundary Layer with Injection and Combustion

Results are presented of the calculation of the velocity field and of the experiments of mean profile measurements in the turbulent boundary layer with injection and combustion. The agreement between the present calculation, which is the extension of the Economos' method, and the experimental results of other investigators is not very good. Thus, the cause of this disagreement is discussed by making use of the results of the present measurements. Through further examination of the same experimental results, some characteristics of the flow are clarified, and the important points to be considered during future study are pointed out

Velocity measurements and flow structure visualizations of a self-sustained oscillating jet

The purpose of this study is the experimental investigation on self-sustained oscillating jet characteristics. Main aim was to describe vertical structures of turbulent air jet issuing from the nozzle of special configuration modified by the controlled oscillations in free jet setup. In the present experiments was used so-called "whistler nozzle", a simple-structured device capable to induce self-sustained excitations with controllable frequencies depending on the nozzle geometrical configuration. The frequency of the excitation measured with a far-field condenser microphone probe was around 1-2 kHz. The jet Reynolds number was in the range 48,000-95,000 in all experimental conditions presented in this paper. Flow field velocity measurements were provided in the free jet setup, with and without self-sustained excitations. The images of both free and impinging jets were taken with a high-speed digital video camera. The flow field and structure of the jet were found to be extremely sensitive to the excitation and dependent on the excitation conditions. This fact can lead to the conclusion that the local heat transfer characteristics of jet impingement are also remarkably dependent on the jet excitation

Surrogate models for the magnitude of convection in droplets levitated through EML, ADL, and ESL methods

Fluid flow and heat transfer in levitated droplets were numerically investigated. Three levitation methods: electro-magnetic levitation (EML), aerodynamic levitation (ADL), and electro-static levitation (ESL) were considered, and conservative laws of mass, momentum, and energy were applied as common models. The Marangoni effect was applied as a velocity boundary condition, whereas heat transfer and radiation heat loss were considered as thermal boundary conditions. As specific models to EML, the Lorentz force, and Joule heat were calculated based on the analytical solution of the electromagnetic field. For the ADL model, besides the Marangoni effect, the flow driven by the surface shear force was considered. For ADL and ESL models, the effect of laser heating was introduced as a boundary condition. All the equations were nondimensionalized using common scales for all three levitations. Numerical simulations were performed for several materials and droplet sizes, and the results were evaluated in terms of the Reynolds number based on the maximum velocity of the flow in the droplet. The order of magnitude of Reynolds numbers was evaluated as $\text{Re} \sim 10^4$ for EML, $\text{Re} \sim 10^3$ for ADL, and $\text{Re} \sim 10^1$ for ESL. Based on the simulation results, we proposed simple formulas for predicting the Reynolds number of droplet internal convection using combinations of nondimensional numbers determined from the physical properties of the material and the driving conditions. The proposed formulas can be used as surrogate models to predict the Reynolds numbers, even for materials other than those used in this study

De novo NSF mutations cause early infantile epileptic encephalopathy

N‐ethylmaleimide‐sensitive factor (NSF) plays a critical role in intracellular vesicle transport, which is essential for neurotransmitter release. Herein, we, for the first time, document human monogenic disease phenotype of de novo pathogenic variants in NSF, that is, epileptic encephalopathy of early infantile onset. When expressed in the developing eye of Drosophila, the mutant NSF severely affected eye development, while the wild‐type allele had no detectable effect under the same conditions. Our findings suggest that the two pathogenic variants exert a dominant negative effect. De novo heterozygous mutations in the NSF gene cause early infantile epileptic encephalopathy

miR-200b Precursor Can Ameliorate Renal Tubulointerstitial Fibrosis

Members of the miR-200 family of micro RNAs (miRNAs) have been shown to inhibit epithelial-mesenchymal transition (EMT). EMT of tubular epithelial cells is the mechanism by which renal fibroblasts are generated. Here we show that miR-200 family members inhibit transforming growth factor-beta (TGF-beta)-induced EMT of tubular cells. Unilateral ureter obstruction (UUO) is a common model of EMT of tubular cells and subsequent tubulointerstitial fibrosis. In order to examine the role of miR-200 family members in tubulointerstitial fibrosis, their expression was investigated in the kidneys of UUO mice. The expression of miR-200 family miRNAs was increased in a time-dependent manner, with induction of miR-200b most pronounced. To clarify the effect of miR-200b on tubulointerstitial fibrosis, we injected miR-200b precursor intravenously. A single injection of 0.5 nM miR-200b precursor was sufficient to inhibit the increase of collagen types I, III and fibronectin in obstructed kidneys, and amelioration of fibrosis was confirmed by observation of the kidneys with Azan staining. miR-200 family members have been previously shown to inhibit EMT by reducing the expression of ZEB-1 and ZEB-2 which are known repressors of E-cadherin. We demonstrated that expression of ZEB-1 and ZEB-2 was increased after ureter obstruction and that administration of the miR-200b precursor reversed this effect. In summary, these results indicate that miR-200 family is up-regulated after ureter obstruction, miR-200b being strongly induced, and that miR-200b ameliorates tubulointerstitial fibrosis in obstructed kidneys. We suggest that members of the miR-200 family, and miR-200b specifically, might constitute novel therapeutic targets in kidney disease