Fin efficiency of serrated fins. Part 4. Correction factor for inline arrangement

A correction factor to the theoretical fin efficiency of serrated fins, reported in Part 1 and Part 2 of this report, was derived for an inline arrangement experimentally. The experiment was performed using an open‐type wind tunnel with six kinds of test finned‐tubes made of copper, carbon steel and stainless steel, which were arranged in one to five rows. Heat transfer measurement was done by the local thermal simulation method. The derived correction factor for the 1st row was the same as for staggered arrangement reported in Part 3, for the 2nd and deeper rows, however, a further correction was needed, which may be caused by the difference in the nonuniformity in heat transfer coefficient over the fin surface. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(4): 258–269, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20008     

Structural, electrical and bending properties of transparent conductive Ga-doped ZnO films on polymer substrates

We investigated the characteristics of highly transparent conductive Ga-doped ZnO (GZO) polycrystalline films of 100 nm thickness deposited on glass and polymer substrates. GZO films were deposited by ion plating with dc-arc discharge. We developed multiple-deposition method to obtain various deposition process temperatures lower than 100 °C. Cross-sectional SEM images show that all the GZO films have columnar structure. Analysis of data obtained by XRD measurements shows that all the GZO films with wurtzite structure exhibit highly (002) orientation perpendicular to the substrate. The resistivity of the GZO films deposited on polyester and glass substrates were 5.0 × 10^-4 Ω · cm. The mechanical bending properties of the GZO films were investigated by comparing the sheet resistance determined before and after a bending test with various bending diameters. For the bending diameter of more than 30 mm, all the GZO films exhibited excellent bending properties with no change in sheet resistance. For the bending diameter of less than 20 mm, we found the sheet resistance affected by the bending. We demonstrated that our multiple-deposition method to achieve different controllable polyester substrate temperatures is highly suitable for improving the bending properties of GZO films.     

First-principles study of structure,vacancy formation,and strength of bcc Fe/V<Subscript>4</Subscript>C<Subscript>3</Subscript> interface

Voids are representative of the damage process in both creep and ductile fractures. Although the matrix/precipitate interface has been considered the preferential nucleation site for voids, the relationship between the atomic structure of this interface and the nucleation mechanism of a void has never been sufficiently investigated. In this study, the bcc Fe/V₄C₃ interface is selected as a model interface between a matrix and precipitate. The vacancy formation energy and intrinsic mechanical strength at this interface are investigated using a first-principles calculation because they should be related with the nucleation of creep and ductile voids, respectively. Within the considered interface, the Fe vacancy is found to be dominant. When the Baker–Nutting orientation relationship is satisfied at the interface, the calculated intrinsic mechanical strength of the interface is 23.8 GPa. However, when the geometric coherence at the interface is low as compared to that of the Baker–Nutting orientation relationship, it is found that the interfacial mechanical strength is significantly weakened. At each interface, it is found that the back-bond of the interface determined the interfacial strength because of the strongly bonded Fe–C on the interface. The nucleation mechanism of a void at the matrix/precipitate interface is discussed based on the present findings. It is suggested that local decohesion at the matrix/precipitate interface should be the origin of the nucleation of a ductile void.     

Directional characteristics of radiation reflection on rough metal surfaces with description of heat transfer parameters

In this paper we clarify directional characteristics of thermal radiation reflection on rough metal surfaces and establish a technique for determining the parameters for heat transfer computation of radiation energy exchange among surfaces. Directional distribution of bidirectional reflectance ρ of surfaces of root‐mean‐square roughness Σ = 0.1 to 1 µm to the irradiation of a visible laser of wavelength λ = 0.6328 µm and to that of an infrared laser of λ = 3.39 µm is investigated experimentally. The optical roughness (Σ/λ) ranges from 0.028 to 1.27. A measure of the magnitude of specular reflection is presented. A model for describing the ρ distribution is presented, and the experimental results of the ρ distribution are analyzed quantitatively and systematically to determine the values of the specular reflection component R_s and the perfect‐diffuse reflection component R_d of the hemispherical reflectance R_H, which are input parameters for radiation heat transfer computation. © 2002 Scripta Technica, Heat Trans Asian Res, 31(2): 76–88, 2002; DOI 10.1002/htj.10008     

TAK-603 selectively suppresses Th1-type cytokine production and inhibits the progression of adjuvant arthritis

Lipopeptides carrying a farnesyl thioether or a palmitic acid thioester and a farnesyl thioether were prepared from S-farnesyl cysteine methyl ester by N-terminal extension of the peptide chain employing the base labile Fmoc blocking group of the palladium(0) sensitive Aloc urethane. By means of this technique a lipohexapeptide representing the completely functionalized, i.e. palmitoylated and farnesylated C-terminus of the human N-Ras protein, was prepared. If acid labile blocking functions like the Boc group were used, upon deprotection an undesired addition of the acid to the double bonds of the farnesyl residue occurred. Therefore, acid labile blocking groups should not be employed in the synthesis of farnesylated lipopeptides. The lipopeptide methyl esters which carry only a farnesyl group do not inhibit protein farnesyl transferase, whereas palmitoylated peptides are weak inhibitors of this enzyme.     

Analysis of asymmetric single-buffer polling and priority systems without switchover times

All previous works on single-buffer polling systems assume a nonzero time for a server to switch stations. In this paper, we consider similar systems with zero switchover times. The performance measures in symmetric systems of this type correspond to those in a well-known machine interference problem. Assuming that the stochastic characteristics vary from station to station, we provide an analysis of imbedded Markov chains to calculate the performance measures. In particular, we derive the state transition probabilities for systems with an arbitrary number of stations. Our approach is also applied to non-preemptive priority systems and systems with a mixture of polling and priority scheduling. Furthermore, we obtain the Laplace-Stieltjes transforms of the probability distribution function of waiting time for both polling and priority systems.