Boundary shear flow past a cylinder near a wall

An investigation on boundary shear flow past a circular cylinder near a wall is numerically performed via a stabilized finite element method. The main focus is to uncover its major difference with the flows corresponding to the symmetry boundary, and to two identical circular cylinders in a side-by-side arrangement. In particular at Reynolds number extensive simulations are made for different gaps between the cylinder and wall. It is noted that in the wake of the cylinder the vortex contour lines shift upwards. At the flow behind a cylinder near the wall may be time dependent. With a reduction of the gap spacing to a magnitude in (0.75,1), the vortex shedding nearly vanishes. For the flow behind two identical circular cylinders side and side, the flow may change from periodic flow to totally irregular one. The drag force CD, lift force CL,rms and Strouhal number St of the circular cylinder near the wall vary differently with the gap, compared with those in the other two cases. When the cylinder is located in the boundary layer, the boundary shear flow has strong effect on the hydrodynamic quantities. Extensive simulations are also made for 400, 600 and 800. It is found that the Reynolds number has strong effect on the flow and force on the cylinder, not only through the variation of Re itself but also the boundary layer of the wall. Withe Re increasing, strong vortex shedding from the near-wall cylinder at starts above a Re in (200, 300)

Effect of temperature on moromi fermentation of soy sauce with intermittent aeration

Soy sauce has been widely used as one of the main seasoning agents in Asian countries. Soy sauce is produced by two-steps fermentation processes, namely koji fermentation and moromi fermentation. Inthis study, different temperatures (25, 35 and 45°C) for moromi fermentation in bioreactor were investigated for understanding their influences on soya sauce quality, in terms of pH variations, ethanolconcentrations and total nitrogen contents in raw soy sauce during moromi fermentation. It was learned that as the aging of moromi took place, the pH level was decreased from pH 7 to 4.88. Also, the soy sauce had lower concentration of ethanol when higher temperature was used in moromi fermentation but the difference of temperature did not show significantly effect on total nitrogen content in soy sauce. This study indicated that the temperature used in the moromi fermentation, coupled with intermittent aeration, imposed significant effects on soy sauce aging and quality. Higher fermentation temperature of 45°C enhanced the aging of soy sauce, accompanying with lower contents of ethanol and higher pH level in soy sauce. However, the total nitrogen content in the soy sauce was notsignificantly influenced by the fermentation temperature

Efficient Communication of Sensors Monitoring Overhead Transmission Lines

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A Review of the Natural History and Laboratory Culture Methods for the Yellow Dung Fly, Scathophaga stercoraria

The yellow dung fly Scathophaga stercoraria (L.) (Diptera: Scathophagidae) is a widespread and locally abundant fly associated with the dung of large mammals, especially farm animals. This species has recently become a standard test organism for evaluating toxic effects of veterinary pharmaceuticals in livestock dung. In this context, a review of its natural history and a general description of the field and laboratory rearing methods of this species are provided here to benefit the scientific community as well as government regulators and applicants of eco-toxicological studies. For guidance, means and ranges are included for all relevant standard life history traits stemming from previously published data on Swiss populations

Preliminary numerical analysis of the seismic response of steel frames with masonry infills retrofitted by buckling-restrained braces

Existing steel moment-resisting frames in several seismic regions worldwide are often characterised by high vulnerability to earthquakes due to insufficient local and/or global ductility. Nowadays, it is of paramount importance to assess their response under strong motions and provide cost-effective retrofitting strategies. Amongst others, the seismic behaviour of these frames is often strongly affected by the presence of masonry infills which, from one side, if adequately distributed, beneficially contribute to the seismic resistance of the structure providing stiffness and strength to the frame, from the other side often experience a brittle behaviour and are very vulnerable to seismic actions. To this end, the H2020-INFRAIA-SERA project HITFRAMES (i.e., HybrId Testing of an Existing Steel Frame with Infills under Multiple EarthquakeS) experimentally evaluated a case study building representative of non-seismically designed European steel frames with masonry infills and investigated a possible retrofit strategy. This paper takes advantage of the experimental results of the HITFRAMES project to calibrate numerical models in OpenSees of a case study building which is analysed as bare, infilled and retrofitted frame with buckling-restrained braces (BRBs). The impact of masonry infills and BRB-retrofit is investigated by comparing the response of models with different configurations. The numerical results provide some insights on the ability of BRB-retrofit option in protecting not only the steel frames from experiencing critical damage during earthquakes but also the masonry infills and on the importance of using appropriate models for the masonry infills in the assessment procedures

Numerical modelling of masonry infill walls in existing steel frames

It is now widely recognised that masonry infill plays an essential role in the seismic behaviour of existing steel buildings; however, there is still a lack of clear guidance on the modelling of masonry infill in the current Eurocode 8-Part 3. Several methods for the numerical modelling of masonry infills have been proposed in literature over the past few decades, which either adopt a detailed approach (micro-model) or a simplified approach (macromodel). In the former case, bricks are individually modelled, taking into account the brickmortar cohesive interface, which is able to provide detailed insights of the behaviour of masonry infills and the frame-wall interaction but usually at a high computational cost. On the other hand, a simplified model can be easily built within finite element software, most of which replace the infill wall panel with one or more equivalent struts in the diagonal direction. It has been demonstrated that the strut models can simulate RC infilled structures’ global response with acceptable accuracy; however, there are still no adequate recommendations for their modelling within steel frames. Besides, these models are generally incapable of capturing the interactions between the infills and the frame members. To this end, the present paper numerically investigates an Abaqus macro-model of the infilled steel frame, which was experimentally tested as part of the recent SERA HITFRAMES project. The preliminary re-sults shows that the different detailing of steel frames could lead to different damage patterns in the infill walls when compared to RC frames. In particular, instead of a single diagonal strut, at most three struts were observed in this study. The results also suggested that the number and geometry of struts could change with increasing displacement demands, hence it might not be appropriate to use the same strut model for infill walls on different floors

Co3O4 particles grown over nanocrystalline CeO2: influence of precipitation agents and calcination temperature on the catalytic activity for methane oxidation

Crystalline cobalt oxides were prepared by a precipitation method using three different precipitation agents, IJNH4)2CO3, Na2CO3 and COIJNH2)2. Cobalt oxide nanoparticles corresponding to a Co3O4 loading of 30 wt% were also deposited over high-surface area nanocrystalline ceria by the same precipitation agents. The effect of calcination temperature, 350 or 650 °C, on the morphological and structural properties was evaluated. Characterization by BET, XRD, SEM, TEM, Raman spectroscopy, H2-TPR, XPS and NH3-TPD was performed and the catalytic properties were explored in the methane oxidation reaction. The nature of the precipitation agent strongly influenced the textural properties of Co3O4 and the Co3O4–CeO2 interface. The best control of the particle size was achieved by using COIJNH2)2 that produced small and regular crystallites of Co3O4 homogeneously deposited over the CeO2 surface. Such a Co3O4–CeO2 system precipitated by urea showed enhanced low-temperature reducibility and high surface Co3+ concentration, which were identified as the key factors for promoting methane oxidation at low temperature. Moreover, the synergic effect of cobalt oxide and nanocrystalline ceria produced stable full conversion of methane in the entire range of investigated temperature, up to 700–800 °C, at which Co3O4 deactivation usually occurs

N = 2 SCFTs: An M5-brane perspective

Inspired by the recently discovered holographic duality between N=2 SCFTs and half-BPS M-theory backgrounds, we study probe M5-branes. Though our main focus is supersymmetric M5-branes whose worldvolume has an AdS_n factor, we also consider some other configurations. Of special mention is the identification of AdS_5 and AdS_3 probes preserving supersymmetry, with only the latter supporting a self-dual field strength.Comment: 27 page

Preferential regulation of stably expressed genes in the human genome suggests a widespread expression buffering role of microRNAs

In this study, we comprehensively explored the stably expressed genes (SE genes) and fluctuant genes (FL genes) in the human genome by a meta-analysis of large scale microarray data. We found that these genes have distinct function distributions. miRNA targets are shown to be significantly enriched in SE genes by using propensity analysis of miRNA regulation, supporting the hypothesis that miRNAs can buffer whole genome expression fluctuation. The expression-buffering effect of miRNA is independent of the target site number within the 3'-untranslated region. In addition, we found that gene expression fluctuation is positively correlated with the number of transcription factor binding sites in the promoter region, which suggests that coordination between transcription factors and miRNAs leads to balanced responses to external perturbations

Research on the Security of Cold-Chain Logistics

In this paper, the definition of cold-chain logistics and security features are analyzed. Based on overview of China's cold-chain logistics, cold chain, through the status quo at home and abroad contrast, we present some of China's food chain problems. With security control system of thought, and risk management theory, the establishment of a more comprehensive evaluation of cold chain logistics system, through a cold-chain business case analysis, put forward suggestions to solve a few cold-chain logistics security strategy