Optical Properties of Polydispersed Atmospheric Aerosols Following Wet Removal

It is well known that size distributions of aerosols influence their optical properties. Many previous studies have focused on the optical properties of aerosols with particular weather conditions, such as haze, fog, or pollution. However, few studies have investigated the influence of precipitation on the optical properties of aerosols. In this study, the optical properties of polydispersed atmospheric aerosols following a wet removal process were investigated. For these calculations, a lognormal distribution was used to represent the raindrop size distribution and the tri-modal aerosol size distributions. Variations in aerosol size distributions and the corresponding changes an extinction coefficient caused by the wet scavenging process were quantified with different compositions of aerosols as a function of rain intensity. The results showed that the extinction coefficient decreased and the corresponding visibility was enhanced with the precipitation duration because of the precipitation scavenging. It was also shown that the rain intensity and the refractive index and size distribution of aerosols influenced the calculations of extinction coefficient of aerosols.     

Functional and Molecular Changes of the Bladder in Rats with Crushing Injury of Nerve Bundles from Major Pelvic Ganglion to the Bladder: Role of RhoA/Rho Kinase Pathway

Voiding dysfunction is a common complication after radical pelvic surgery. To reduce this complication, nerve-sparing radical pelvic surgery was introduced. However, several patients experienced voiding difficulty despite nerve-sparing radical pelvic surgery. Thus, we investigated the functional and molecular changes of the bladder in rats, which demonstrated voiding dysfunction induced by nerve damage during nerve-sparing radical pelvic surgery. Male rats were used and assigned to normal, sham-operated, and bilateral crushing nerve bundles from major pelvic ganglion (MPG) to bladder group. After one, two, and four-week crushing injury, significantly decreased contractile response and increased connective tissue of the detrusor were observed and these results were reliable findings with voiding difficulty following nerve-sparing radical pelvic surgery. After crushing injury, significantly increased M2 muscarinic receptor expression was observed and this might be regarded as the compensatory response. However, M3 muscarinic receptor expression was not significantly changed. The expression of RhoA, ROCK-α, and ROCK-β was significantly increased after one, two, and four-week crushing injury. From these results, the down-regulation of RhoA/Rho kinase pathway might lead to the decreased bladder contractility after crushing injury of nerve bundles from MPG to the bladder despite of the compensated up-regulation of M2 muscarinic receptor.     

Customer''s time-variant purchase behavior and corresponding marketing strategies: an online retailer''s case

The traditional customer relationship management (CRM) studies are mainly focused on CRM in a specific point of time. The static CRM and derived knowledge of customer behavior could help marketers to redirect marketing resources for profit gain at the given point in time. However, as time goes on, the static knowledge becomes obsolete. Therefore, application of CRM to an online retailer should be done dynamically in time. Though the concept of buying-behavior-based CRM was advanced several decades ago, virtually little application of the dynamic CRM has been reported to date.

In this paper, we propose a dynamic CRM model utilizing data mining and a monitoring agent system to extract longitudinal knowledge from the customer data and to analyze customer behavior patterns over time for the retailer. Furthermore, we show that longitudinal CRM could be usefully applied to solve several managerial problems, which any retailer may face.     

Copper nanofiber-networked cobalt oxide composites for high performance Li-ion batteries

We prepared a composite electrode structure consisting of copper nanofiber-networked cobalt oxide (CuNFs@CoO _x ). The copper nanofibers (CuNFs) were fabricated on a substrate with formation of a network structure, which may have potential for improving electron percolation and retarding film deformation during the discharging/charging process over the electroactive cobalt oxide. Compared to bare CoO _x thin-film (CoO _x TF) electrodes, the CuNFs@CoO _x electrodes exhibited a significant enhancement of rate performance by at least six-fold at an input current density of 3C-rate. Such enhanced Li-ion storage performance may be associated with modified electrode structure at the nanoscale, improved charge transfer, and facile stress relaxation from the embedded CuNF network. Consequently, the CuNFs@CoO _x composite structure demonstrated here can be used as a promising high-performance electrode for Li-ion batteries.     

Round-robin test on thermal conductivity measurement of ZnO nanofluids and comparison of experimental results with theoretical bounds

Ethylene glycol (EG)-based zinc oxide (ZnO) nanofluids containing no surfactant have been manufactured by one-step pulsed wire evaporation (PWE) method. Round-robin tests on thermal conductivity measurements of three samples of EG-based ZnO nanofluids have been conducted by five participating labs, four using accurate measurement apparatuses developed in house and one using a commercial device. The results have been compared with several theoretical bounds on the effective thermal conductivity of heterogeneous systems. This study convincingly demonstrates that the large enhancements in the thermal conductivities of EG-based ZnO nanofluids tested are beyond the lower and upper bounds calculated using the models of the Maxwell and Nan et al. with and without the interfacial thermal resistance.     

Fabrication of aluminum nano-scale structures using direct-embossing with a nickel template

Al plate was patterned by a direct embossing process. An electroformed Ni plate with a nano-sized surface protrusion pattern was used as an embossing mold. The Ni stamp with a nano-sized surface protrusion pattern was pressed onto an electro-polished Al plate; thus, a reversed Al nano-pattern was formed on the Al surface by the localized plastic deformation of Al. The Al plate was softened by annealing at 400 °C for 5 min; thus, high-fidelity pattern transfer was achieved at a low embossing pressure.     

A study on flow characteristics and discharge coefficients of safety valve used in LNG/LNG-FPSO ships

The safety valves used in liquefied natural gas — floating production storage and offloading (LNG-FPSO) ships play an important role in maintaining a fixed pressure by controlling the release of liquefied natural gas (LNG) from pipes in an LNG piping system. Therefore, the discharge coefficient is regarded as the most important parameter influencing the valve performance. In order to satisfy the ship’s classification criteria, the discharge coefficient of the safety valve must usually be over 0.8. Despite the importance of a good understanding of the flow phenomena inside the safety valve for the improvement of the discharge coefficient, the successful design of valves depends on experience and experiments in an industrial field. In this study, a computational fluid dynamics (CFD) investigation was carried out with ANSYS-CFX software to observe the flow phenomena inside the valve and to determine the discharge coefficients from changes in the valve lift, which is the distance between the exit of the nozzle and the lower part of the disc plate. The discharge coefficients obtained were also verified through comparison with available experimental data.     

The effect of man made source processes on the behavior of total gaseous mercury in air: a comparison between four urban monitoring sites in Seoul Korea

Concentrations of total gaseous mercury (TGM) were measured continuously at four urban residential locations (G (Guro-gu); N (Nowon-gu); S (Songpa-gu); and Y (Yongsan-gu)) in Seoul, Korea from 2004 to 2009. The mean concentrations of Hg at these sites were found on the order of N (3.98 ± 1.68 ng m^− 3), S (3.87 ± 1.56 ng m^− 3), G (3.80 ± 1.60 ng m^− 3), and Y (3.36 ± 1.55 ng m^− 3). Evidence indicates that the spatial distribution of Hg should be affected by the combined effects of both local anthropogenic (incineration facilities and thermal power plants) and natural (soil) emission sources in association with the meteorological parameters. Inspection of the Hg temporal patterns indicates the co-existence of contrasting seasonal patterns between the central site Y (winter dominance) and all other outbound sites near city borders (summer dominance). The long-term trend of Hg, if examined by combining our previous studies and the present one, shows that Hg levels in this urban area declined gradually across decadal periods despite slight variabilities in spatial scale: (1) above 10 ng m^− 3 in the late 1980s, (2) ~ 5 ng m^− 3 in the late 1990s, and (3) ~ 3 ng m^− 3 toward the late 2000s. The results of the principal component analysis along with observed differences in seasonal patterns (between study sites) suggest that Hg distributions between different urban sites are greatly distinguishable with strong source signatures at each individual site.     

Instability prediction of GO2/GCH4 flames in a single recessed coaxial injector using 1D lumped network model

Journal of Mechanical Science and Technology - This study analyzes the effect of changes in input parameters on the prediction results in combustion instability. First, applying the centroid...