A methodology to work on geometrically complex heat transfer systems: the cases of heat conduction through composite slabs

Geometrical complexity considered in the present study is characterized by a large degree of freedom in placement of constituents in a composite system. The constituent sizes are not negligibly small compared to the system’s expanse, so approximations of their configurations and placement patterns by some simple equivalents are not feasible. Numerical analysis is a means to estimate heat transfer performance of the system, but a strategy is required to navigate through a vast number of possible constituent patterns to find ones that produce higher heat transfer performance. In the proposed methodology the constituent pattern is captured as a two-dimensional mosaic image of solid cells embedded in a substrate. On an image assumed as a starter, the singular-value decomposition (SVD) analysis is performed to find its (SVD) building block elements. By shuffling the building block elements variants of the starter image are created. Heat transfer analysis is performed on sample systems that are picked up from the ensemble of variants. Using the Taguchi method and through a genetic algorithm-type reasoning, those element arrangements that do not significantly affect the heat transfer performance are weeded out. The methodology is demonstrated on the cases of heat conduction through composite slabs.     

Optical Transition in Reduced C60 Thin Films

Absorption spectra of C60 thin film reduced in an electrochemical cell are studied. The results are compared with data of chemically reduced C60 anions. Absorption with relatively broad line-width below the energy of 1 eV is observed in the film besides the peaks at 1.14 ∼ 1.4 eV observed in C60 anion solution. The electronic states of reduced COT are discussed in terms of the solid state effect.     

Estimation of friendship and hierarchy from conversation records

We have developed a method for estimating the level of friendship between two people and the strength of their hierarchy. This information is important because building the relationships needed to create something new requires an understanding of current relationships. Using records of conversation among people, our method first identifies the sentence types and then uses the identified types to estimate the level of friendship and the strength of the hierarchy. Testing using records for various types of conversation demonstrated that this method can robustly estimate both values from one-person-fixed conversation records.     

Absorption and Electrical Conductivity during Electrochemical Reduction in Fullerene Film

The results of in-situ measurements of optical absorption and electrical conductivity in C₆₀/C₇₀ (9/1) film during electrochemical reduction in a cell using solid polymer electrolyte are reported. The drastic change of absorbance and the increase of conductivity upon Li doping were obtained and the results are discussed.     

Experimental and mathematical evaluation of trichloroethylene removal from saturated soil using acetic acid with saturated ozone

The present study is an experimental and numerical analysis of trichloroethylene (TCE) removal from soil by ozone oxidation combined with acetic acid flushing. A one-dimensional advective–dispersive flow model is proposed to mathematically describe the TCE dissolution and oxidation from the porous medium using acetic acid and ozone, respectively. The model could reasonably well predict the experimental data in the effluent for dissolution, oxidation, and total removal of TCE. Sensitivity analyses evaluated the effects of different parameters, such as ozone and acetic acid concentration, flow rate, and initial TCE concentration, on the dissolution and oxidation processes. Remediation time was reduced by more than 29% by applying acetic acid solutions saturated with ozone. Increasing the ozone concentration was the best method for reducing remediation time, followed by increasing acetic acid concentration and increasing flow rate.     

Electroplasticity memory devices using conducting polymers and solid polymer electrolytes

Erasable memory devices are fabricated by the combination of a conducting polymer and solid polymer electrolyte. The former is used as a memory channel and the latter as an electrolyte medium. The channel conductivity can be controlled over 3-4 orders of magnitude by electrochemical doping through a writing electrode. The response time, depending on the writing voltage, is several seconds. The characteristics of the memory device are discussed.     

New Lanthanoid Metallofullerenes and their HPLC Elution Behavior

HPLC behaviors of metallofullerenes of 14 lanthanoid elements were studied by use of radiotracers, and the species of some of the metallofullerenes were identified by mass spectroscopy. From the HPLC elution behaviors, 14 lanthanoid elements forming metallofullerenes were found to be grouped into two, namely, Sm, Eu, Tm and Yb as one group and the rest of the elements as another. Some new species of metallofullerenes like La@C₇₄, and M@C_n (M=Eu, Tm, Yb; n=74, 82, 84, 88, 90, 92, 94) have been identified. The observed retention times of metallofullerenes are discussed in terms of the number of carbon atoms of the cage and from consideration of the electron donor and acceptor relation between the fullerene species and the HPLC stationary phases.     

Stability of electrochemomechanical strains in polypyrrole films using ionic liquids

Electrochemomechanical strain (ECMS) of conducting polymers, polypyrrole (PPy) films was studied using several kinds of ionic liquids and the mixed solution with organic solvents from the view points of strain and stability. The PPy films, which were electrodeposited from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), showed porous morphology. The ECMS in the films operated in ionic liquids was less than 5%, demonstrating a cation movement behavior and stable cycling. By the operation in ionic liquid/propylene carbonate (PC) mixed solution, the ECMS increased up to 24% showing the anion movement, and gradually decreased upon cycling to 16% at 10^th cycle. The strain and stability of the ECMS in mixed electrolyte solution with various ratios of the ionic liquid and PC were studied and discussed in terms of mechanisms of ECMS in mixed solutions.     

连铸工艺中弯月面控制的发展

在生产效率和板坯质量方面,连铸工艺中的弯月面控制总是十分重要的.为了掌握弯月面控制的发展方面,本文首先概括介绍早期针对生产效率而采用的弯月面控制技术,进而介绍当前为了提高板坯质量而采用的顶部凹槽的弯月面控制技术.80年代,两项关于生产效率的弯月面控制技术发展起来.一项是结晶器状况监测系统,另一项是高速结晶器调宽技术.至于板坯质量方面,最近我们发展了在结晶器周围加上低频交流电磁场的电磁连铸技术(EMC),并且开展了中间实验和连铸生产规模的应用研究.关于EMC技术在弯月面控制的三方面作用得到证实,即结晶器和凝固坯壳之间的软接触,垂直搅拌,焦耳热使初始凝固阶段能适度冷却.     

Ozone decomposition of hazardous chemical substance in organic solvents

Performance on the ozonation of hazardous chemicals in non-aqueous solutions, i.e. organic solvents, was studied in comparison with those in water. The specific conclusions obtained from this study are as follows: the rate of decomposition and the specific amount of decomposition per ozone consumption for orange II were higher in organic solvents like acetic acid, acetone, ter-butyl alcohol than in distilled water. The rates of trichloroethylene decomposition in organic solvents like acetic acid, acetone, and ethyl acetate were also higher than those in distilled water.