Numerical simulation of ice accretion phenomena on rotor blade of axial blower

Ice accretion is the phenomenon that super-cooled water droplets impinge and accrete on a body. It is well known that ice accretion on blades and airfoils leads to performance degradation and severe accidents. For this reason, experimental investigations have been carried out using flight tests or icing tunnels. However, it is too expensive, dangerous, and difficult to set actual icing conditions. Hence, computational fluid dynamics is useful to predict ice accretion. A rotor blade is one of jet engine components where ice accretes. Therefore, the authors focus on the ice accretion on a rotor blade in this study. Three-dimensional icing phenomena on the rotor blade of a commercial axial blower are computed here, and ice accretion on the rotor blade is numerically investigated.     

Enhanced production of extracellular inulinase by the yeast Kluyveromyces marxianus in xylose catabolic state

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Microbial community structure in deep natural gas-bearing aquifers subjected to sulfate-containing fluid injection

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Headspace GC/MS analysis of residual vinyl chloride and vinylidene chloride in polyvinyl chloride and polyvinylidene chloride products

A headspace GC/MS analysis method for the simultaneous determination of residual vinyl chloride (VC) and vinylidene chloride (VDC) in polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC) products was developed. A test sample was swelled overnight with N,N-dimethylacetamide in a sealed vial. The vial was incubated for 1 hour at 90 degrees C, then the headspace gas was analyzed by GC/MS using a PLOT capillary column. The recoveries from spiked PVC and PVDC samples were 90.0-112.3% for VC and 85.2-108.3% for VDC. The determination limits were 0.01 microg/g for VC and 0.06/microg/g for VDC, respectively. By this method, VC was detected in two PVC water supply pipes at the levels of 0.61 and 0.01 microg/g. On the other hand, VC and VDC were not detected in any of the food container-packages or toys tested.     

Rapid quantification of coliforms in ready-to-eat foods using lateral-flow immunochromatographic assay

The degree of coliform contamination in pastries was estimated based on culturing times until positive results were obtained with the lateral-flow immunochromatographic assay (LFIA). Coliform genera Citrobacter, Cronobacter, Enterobacter, Klebsiella, Kluyvera, Pantoea, Raoultella, and Serratia were detected in spoiled pastries, as established with next-generation sequencing. A lateral-flow test strip was constructed using antibodies recognizing the above genera. The culture times required for positive detection with LFIA were 0, 3, 6, and 9 hr at initial inoculation concentrations of 3.8, 2.8, 1.8, and 0.8 log₁₀ (cfu/ml), respectively. In pastries contaminated with >5.0, 3.0–5.0, 2.0–3.0 log₁₀ (cfu/g) coliform bacteria, samples became LFIA-positive from 3, 6, and 9 hr culture, respectively. LFIA showed negative for pastries with <2.0 log₁₀ (cfu/g) coliform contamination. The quantitative category of initial coliform content before culture was predictable with 87% accuracy. This novel method can be applied to monitor food safety of other ready-to-eat consumables.     

Integrated solutions for urban runoff pollution control in Brazilian metropolitan regions

One of the most important causes for poor water quality in urban rivers in Brazil is the low collection efficiency of the sewer system due to unforeseen interconnections with the stormwater drainage system. Since the beginning of the 20th century, Brazilian cities have adopted separate systems for sanitary sewers and stormwater runoff. Gradually these two systems became interconnected. A major challenge faced today by water managers in Brazil is to find efficient and low cost solutions to deal with this mixed system. The current situation poses an important threat to the improvement of the water quality in urban rivers and lakes. This article presents an evaluation of the water quality parameters and the diffuse pollution loads during rain events in the Pinheiros River, a tributary of the Tietê River in S?o Paulo. It also presents different types of integrated solutions for reducing the pollution impact of combined systems, based on the European experience in urban water management. An evaluation of their performance and a comparison with the separate system used in most Brazilian cities is also presented. The study is based on an extensive water quality monitoring program that was developed for a special investigation in the Pinheiros River and lasted 2.5 years. Samples were collected on a daily basis and water quality variables were analyzed on a daily, weekly or monthly basis. Two hundred water quality variables were monitored at 53 sampling points. During rain events, additional monitoring was carried out using an automated sampler. Pinheiros River is one of the most important rivers in the S?o Paulo Metropolitan Region and it is also a heavily polluted one.     

Characteristics of solidification and melting in the water‐saturated porous medium cooled from the top (response of solid–liquid interface due to time‐varying cooling temperature)

This paper describes the response of a solid–liquid interface in a water‐saturated porous box to a time‐varying cooling temperature. Spherical soda glass beads with an average diameter of 5 mm constitute a porous matrix. The lower boundary of the matrix is kept at 8°C at all times during the experiments, while the upper plate is set at a temperature, lower than the liquids 0°C. After a steady state is reached, the cooling temperature is varied periodically with a fixed amplitude of 4°C. The solid–liquid interface positions are measured and the characteristic amplitudes and the phase delays are determined for different periods ranging from one hour to ten hours at four different cooling temperatures. It has been found that the amplitude of the interface is proportional to the cooling temperature period length, and that a thicker solid layer causes larger phase delays. The proposed one‐dimensional model has been found appropriate for predicting the response of the horizontally averaged position of the solid–liquid interface. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(5): 330–341, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20015     

Multifunctional High‐Power Sources for Smart Contact Lenses

Powering an electrical contact lens is a significant challenge for wearable applications such as augmented reality displays and iontophoretic drug delivery to the eye. Here a hybrid power generation device is developed comprising a wireless power transfer system and a bioabsorbable metal–air primary battery, which provides a multifunctional direct current (DC) and/or alternating current (AC) output. The DC power is generated by Zn loop anode and a bilirubin oxidase (BOD) biocathode in an artificial tear. The Zn‐based loop anode is also used as the antenna of a wireless power transfer system that results in high power transfer efficiency of 17.6% at 13.56 MHz. The wireless‐powered AC voltage is boosted from 1.5 to 1.5 V + 0.5 V_pp by a DC offset, enabling red light‐emitting diode (LED) emission. Furthermore, the hybrid AC and DC offset voltages are boosted to 2.3 V + 0.5 V_pp by a capacitive booster circuit that provides blue LED emission. No hydrogen evolution or pH change is observed in the tear electrolyte. The present hybrid power source can potentially power wearable electronics in body fluids.     

Tailoring Amino‐Functionalized Graphitic Carbon‐Encapsulated Gold Core/Shell Nanostructures for the Sensitive and Selective Detection of Copper Ions

The effective transfer of strong electromagnetic field from the gold core through the coating shell represents the most significant challenge for the applications of plasmonic nanoparticles. This study applies a one‐step arc discharge method to synthesize graphitic carbon‐encapsulated gold nanoparticles (Au@G NPs) functionalized with amino groups uniformly via adding NH₃ into He background gas. By tailoring the coating shell into few‐layered graphene, a strong localized surface plasmon resonance (LSPR) absorption band is achieved. The NH₃ introduces H radicals to strengthen the LSPR characteristic by etching the coating graphitic shell, as well as provides dissociated NH or NH₂ species to functionalize the surfaces with amino groups. With an LSPR‐based colorimetric method, it is demonstrated that trace Cu²⁺ ions can be detected rapidly with excellent sensitivity (as low as 10 × 10^‐9m linearly) and selectivity against other metal ions (Na⁺, K⁺, Mg²⁺, Ca²⁺, Co²⁺, Fe²⁺, Cd²⁺, Pb²⁺, and Hg²⁺ ions) by amino‐functionalized Au@G NPs in water samples.     

A method of eliminating B-mode dielectric breakdown failure in gateoxides utilizing a charging phenomenon

An investigation of the dielectric breakdown characteristics of charged samples is discussed. B-mode dielectric breakdown failure was eliminated by scrubbing gate oxide films using a brush. Various scrubbing experiments revealed that this occurred due to charging to a voltage close to the intrinsic breakdown voltage of the gate oxide film. Other characteristics such as C-V curves and time-dependent dielectric breakdown characteristics were not degraded by the charging. The method can be of value in the manufacture of reliable oxide films in ULSI