Wheel/rail contact dynamics in turnout negotiations with combined nodal and non-conformal contact approach

In railroad turnouts, geometries of tongue and crossing rails are very complex and their shapes are changing along the track. Therefore, wheels are subjected to not only tread and flange contacts, but also the back-of-flange and top-of-flange contacts in the case of spring switches of tram vehicles. For this reason, one needs to deal with significant jumps in contact points for solving wheel/rail contact problems in turnout, and an accurate prediction of jumps in contact points is one of the most important issues that need to be carefully handled in the dynamic simulation of vehicle/turnout interactions. In this investigation, a numerical procedure that can be used for solving such a complex wheel/rail contact problem in turnout is proposed. In particular, a combined nodal and non-conformal contact approach is developed such that significant jumps in contact points are detected using the nodal search, while the exact location of contact point is then determined with continuous surface parameterizations using non-conformal contact equations. With this combined nodal and non-conformal contact approach for the contact geometry analysis of vehicle/turnout interactions, multiple look-up contact tables can be generated in an efficient way without losing accuracy. Since detailed contact search is performed off-line to obtain look-up contact tables, significant changes in contact points in turnout can be efficiently predicted on-line with tabular data to be interpolated in a standard way. Several numerical examples are presented in order to demonstrate the use of the numerical procedure developed in this investigation.     

Screening of Inhibitors Targeting Heat Shock Protein 47 Involved in the Development of Idiopathic Pulmonary Fibrosis

Heat shock protein 47 (HSP47), a collagen-specific molecular chaperone, is causally related to fibrotic diseases, including idiopathic pulmonary fibrosis. The identification of Compounds that interfere with the HSP47-collagen interaction is essential for the development of relevant therapeutics. Herein, we prepared human HSP47 as a soluble fusion protein expressed in E. coli and established an assay system for HSP47 inhibitor screening. We screened a natural and synthetic Compound library established at Nagasaki University. Among 1023 Compounds, 13 exhibited inhibitory activity against human HSP47, of which three inhibited its function in a dose-dependent manner. Epigallocatechin-3-O-gallate, one of these three Compounds, is a typical polyphenol Compound derived from tea leaves. Structurally related Compounds were synthesized and examined for their activity, revealing a hydroxyl group at A-ring position 5 as important for its activity. The present findings provide valuable insight for the development of natural product-derived therapeutics for fibrotic diseases, including idiopathic pulmonary fibrosis.     

Numerical simulation of parallel-plate particle separator for estimation of charge distribution of PM2.5

A numerical simulation of an instrument that is used to measure the charging state of PM2.5 is conducted in order to clarify its measurement uncertainty and to improve its performance. The instrument, a parallel-plate particle separator (PPPS), is designed to classify aerosol particles according to their charging states and measure their quantities. The trajectories of submicron particles in the PPPS are numerically analyzed using the Lagrangian particle tracking method, taking into account the Brownian force and the electrostatic force. First, it is confirmed that the deterioration in the classification accuracy observed in the experiment is due to Brownian diffusion. The optimal condition that improves the accuracy is investigated through a parametric study by varying the balance of flow rates at the inlets, the geometry of the inlet and exit sections, and the applied voltage. It is found that decreasing the flow rate of the central inlet for aerosol or narrowing the central inlet improves the accuracy. The dependence of the accuracy on the flow rate is found to be in accordance with the experimental results. For charged particles, an optimum voltage that maximizes the classification accuracy is found. On the basis of the simulation results, we propose a method to determine the charge distribution of aerosol from the number of particles counted at each exit of the PPPS. In the test assuming aerosol in the air, the charge distribution determined from the number count at the exits is found to perfectly agree with the charge distribution specified at the inlet.

Copyright © 2019 American Association for Aerosol Research     

The Atmospheric Scanning Electron Microscope with open sample space observes dynamic phenomena in liquid or gas

Although conventional electron microscopy (EM) requires samples to be in vacuum, most chemical and physical reactions occur in liquid or gas. The Atmospheric Scanning Electron Microscope (ASEM) can observe dynamic phenomena in liquid or gas under atmospheric pressure in real time. An electron-permeable window made of pressure-resistant 100 nm-thick silicon nitride (SiN) film, set into the bottom of the open ASEM sample dish, allows an electron beam to be projected from underneath the sample. A detector positioned below captures backscattered electrons. Using the ASEM, we observed the radiation-induced self-organization process of particles, as well as phenomena accompanying volume change, including evaporation-induced crystallization. Using the electrochemical ASEM dish, we observed tree-like electrochemical depositions on the cathode. In silver nitrate solution, we observed silver depositions near the cathode forming incidental internal voids. The heated ASEM dish allowed observation of patterns of contrast in melting and solidifying solder. Finally, to demonstrate its applicability for monitoring and control of industrial processes, silver paste and solder paste were examined at high throughput. High resolution, imaging speed, flexibility, adaptability, and ease of use facilitate the observation of previously difficult-to-image phenomena, and make the ASEM applicable to various fields.     

Effect of water distribution in gas diffusion layer on proton exchange membrane fuel cell performance

Water management of proton exchange membrane fuel cells remains a prominent issue in research concerning fuel cells. In this study, the gas diffusion layer (GDL) of a fuel cell is partially treated with a hydrophobic agent, and the effect of GDL hydrophobicity on the water distribution in the fuel cell is examined. First, the effect of the position of the cathode GDL hydrophobic area relative to the channel on the fuel cell performance is investigated. Then, the water distribution in the fuel cell cathode GDL is observed using X-ray imaging. The experimental results indicate that when the hybrid GDL's hydrophobic area lies on the channel, water tends to accumulate under the rib, and the water content in the channel is low; this improves the fuel cell performance. When the hydrophobic area is under the rib, the water distribution is more uniform, but the performance deteriorates.     

Preparation of Polymer-Based Nanocomposites Composed of Sustainable Organo-Modified Needlelike Nanoparticles and Their Particle Dispersion States in the Matrix

Polymer-based nanohybrid materials were created using sustainable sepiolite clay composed from ubiquitous elements. Although sepiolite is generally recognized as a fibrous natural clay mineral, it turned out to be an acicular microcrystal because of the organo-modification of the outermost surface. Surface modification was performed using phosphonic acid derivatives containing hydrocarbon chains or fluorocarbon chains. Formation of a bidentate bond enhanced the desorption temperature and made nanocomposite preparation possible by melt compounding with polymers having a high melting point. As a result of organo-modification, amphiphilic sepiolite was obtained, and nanodispersion in an organic solvent was achieved. This technology was useful for detailed evaluation of sepiolite morphology. The nanocomposite of crystalline polymers/organo-modified sepiolites achieved uniform dispersion of these nanofillers in the matrix polymer. The introduction of 1 wt% nanofillers did not impair the transparency of the matrix polymer. As a result, a lamellae structure of the polymer developed, the crystallinity increased, and the mechanical properties improved. In addition, the crystallization temperature was improved, indicating that organo-modified sepiolites may act as a nucleating agent. It was found that sepiolite nanofiller with a highly aggregated tendency can achieve a well-nanodispersed state, even in phase-separable fluoropolymers, by applying fluorocarbon modification. POLYM. ENG. SCI., 60:541–552, 2020. © 2019 Society of Plastics Engineers     

Cu behaviors and effects of mine drainage in Kosaka River,Hokuroku mining district,Northeast Japan

Focusing on the origin of the heavy metal, this study aims to build an imputed method to estimate the heavy metal content in river water by making a distinction between the heavy metal of natural origins and that caused by human activities. Supported by GIS, Kosaka watershed within the Hokuroku basin was divided into several sub-watershed polygons and the outflows of water and Cu were calculated for each polygon. Compared with the natural origin, the dominant Cu emissions affected the river water more significantly in local. Based on the mass balance closure, the heavy metal content of Cu in the Kosaka River was estimated by the conflux accumulation of tributaries and mine drainages. The estimated Cu concentrations were checked by comparing with the actually measured values at monitoring points along the Kosaka River and the results are coincidence with each other in general. It is revealed that the mainstream water quality could be estimated by seizing the water quality of upstream tributaries and human drainages.     

Effects of supplied gas humidity change on PEFC transient power generation

Polymer electrolyte fuel cells (PEFCs, PEMFCs) are gaining increasingly more attention as clean and efficient energy‐conversion devices. Vapor and liquid transport has a strong impact on the power generation characteristics and efficiency of PEFCs, and so proper water management is needed for efficiency and durability. However, water transport factors are not well understood, particularly during unsteady operation—often the case in vehicles and distributed stationary power generators. In this study, to understand and generalize the effects of local water transport on PEFC performance, transient mass transport characteristics inside a PEFC were investigated experimentally and numerically. For this purpose, we developed an unsteady two‐dimensional numerical model based on mass‐ and charge‐conservation equations in the channel, gas diffusion layer (GDL), and membrane electrode assembly (MEA). As necessary parameters for model development, we measured the water content of the MEA, the membrane resistivity, the activation overvoltage, overall mass transfer coefficient, and so on. The membrane resistivity greatly increases as the relative humidity decreases. The activation overvoltage is also affected by the relative humidity, and not only by the current density and oxygen activity. Current load and voltage changes are frequently used as PEFC transient inputs, but lead to very complicated and intractable phenomena such as changes in the amount of generated water and electro‐osmosis, state of the electrical double layer, and so on. Hence, stepwise changes in the relative humidity of the supplied gas were adopted in this study. The experimental and numerical transient responses were in good agreement under most operating conditions, and the reliability of our measurement methods for the water transport properties and our numerical model were confirmed. Here we discuss the dominant factor in the transient responses, and conclude that the transport resistance at the PEM–GDL interface is the largest and most dominant factor in a relatively dry state under unsteady operating conditions. © 2011 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20371     

Morphologic analysis of odontogenic cysts with computed tomography

PURPOSE: The purpose of this study was to analyze the effects of lesion site and epithelial keratinization on the morphologic characteristics of odontogenic cysts and clarify determinate factors for cyst morphology. MATERIAL AND METHODS: Computed tomographic images of 92 odontogenic cysts were analyzed: 31 primordial, 31 dentigerous and 30 radicular. Thirty-four cysts were located in the maxilla (6 primordial, 10 dentigerous, and 18 radicular) and 58 in the mandible (25 primordial, 21 dentigerous, and 12 radicular). Histologically, 31 cysts showed epithelial keratinization (18 primordial and 13 dentigerous). No keratinization was seen in radicular cysts. The morphologic features of cysts were assessed by measuring long length parallel to dental arch and short length vertical to it and calculating the long/short ratio. In addition, the computed tomography pattern of the cyst was classified into unilocular, lobulated, and multilocular patterns. Appearance of the sclerotic rim and surrounding cortex were classified into three and four patterns respectively to evaluate the developmental features of the cyst. RESULTS: As a whole, the long length of the primordial cysts was statistically larger than the other two cyst groups and resulted in a larger long/short ratio. Statistical differences of CT pattern were also seen among cyst groups. There was no preference in any cyst group for the appearance of the sclerotic rim and cortex. There were statistical differences between maxilla and mandible in short axis and long/short ratio. The maxillary cysts generally showed round shapes irrespective of their histologic characteristics. A multilocular pattern was more frequent in the keratinized group of mandibular primordial cysts. In dentigerous cysts, a multilocular pattern was seen only in the keratinized group and the long/short ratio was statistically larger; cyst shape was elliptical along the long axis. CONCLUSION: Our results demonstrated morphologic differences of odontogenic cysts caused by lesion site and keratinization. The dentigerous cyst with predominant keratinization should be included in the primordial cyst (odontogenic keratocyst) group.     

Sonographic analysis of recurrent parotitis in children: a comparative study with sialographic findings

BACKGROUND: Patients with asthma show altered surface expression of the adhesion molecules CD11b and L-selectin on airway granulocytes compared with blood granulocytes. OBJECTIVE: To investigate whether this modulation is related to disease activity or due to transendothelial migration, we compared the CD11b and L-selectin expression on blood and induced sputum eosinophils and neutrophils between patients with asthma and normal subjects. METHODS: Eleven normal subjects (21-43 years), nine patients (21-34 years) with mild atopic asthma and 10 patients (20-47 years) with moderate to severe atopic asthma on regular treatment with inhaled steroids underwent sputum induction by inhalation of nebulized hypertonic saline (4.5%). CD11b and L-selectin expression on granulocytes from blood and DTT-homogenized sputum were analysed by flow cytometry. Eosinophils could be discriminated from neutrophils by using depolarized light scatter. Disease activity was assessed by baseline FEV1 and airway responsiveness to histamine (PC20). RESULTS: Sputum eosinophils showed higher expression of CD11b (P<0.001) and lower expression of L-selectin (P<0.001) compared with peripheral blood eosinophils. CD11b and L-selectin expression on eosinophils from blood or sputum did not differ between the three groups. Similar results were obtained for neutrophils. The PC20 in the patients with moderate-to-severe asthma was related to CD11b expression on blood (R=-0.92, P=0.001) and sputum eosinophils (R=0.75, P=0.02). CONCLUSIONS: Flow cytometry of induced sputum granulocytes from asthmatic as well as normal subjects is feasible. We conclude that the modulated expression of CD11b and L-selectin on airway granulocytes is not specific for asthmatic airway inflammation, but is probably the result of tissue migration per sé. This implies that CD11b and L-selectin expression on granulocytes in induced sputum cannot be used as marker of disease activity.