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71.
Corrosion Properties of NdFeB Magnets Coated by a Ni/Cu/Ni Layer in Chloride and Sulfide Environments 总被引:2,自引:0,他引:2
I. Rampin F. Bisaglia M. Dabalà 《Journal of Materials Engineering and Performance》2010,19(7):970-975
In this study, the corrosion behavior of a permanent magnetic alloy, Nd-Fe-B, coated by a triple layer of nickel-copper-nickel
was studied. The corrosion resistance was investigated by (i) flux tests, carried out at 90 °C in an atmosphere containing
chlorides or at 70 °C containing sulfides, (ii) electrochemical impedance spectroscopy (EIS), and (iii) potentiodynamic polarization
tests, carried out in solution at different temperatures (0-90 °C) containing chlorides or sulfides. The morphology and the
composition of the samples and the corrosion products were analysed by optical microscopy and scanning electron microscopy,
equipped with an energy dispersive x-ray detector. The magnetic properties were characterized by magnetic flow measurements.
The flux tests indicated that the triple layer of coating provided a greater corrosion resistance in atmosphere containing
chlorides than the one with sulfides. The potentiodynamic and the EIS tests showed that the corrosion rate increased with
temperature. The magnetic properties of the sample remained unchanged after exposure to the aggressive environment. 相似文献
72.
Javier Guerrero Carlota Tayà Albert Guisasola Juan A. Baeza 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(10):1508-1511
The interaction between enhanced biological phosphorus removal (EPBR) and biological nitrogen removal may result in EBPR failure in full‐scale wastewater treatment plants (WWTPs). This work studies one of the common causes of this failure: the presence of nitrate in the anaerobic phase, which may act as an inhibitor for polyphosphate accumulating organisms (PAO) activity or may activate the competition between PAO and denitrifying bacteria for the carbon source. Several batch experiments were performed with different carbon sources (acetic acid, propionic acid and sucrose) at different nitrate concentrations using PAO‐enriched sludge from two different pilot plants: an anaerobic/aerobic sequential batch reactor (SBR) and an anaerobic/anoxic/aerobic (A2/O) continuous plant. The results imply that the operational conditions of the A2/O pilot plant selected a PAO population capable of i) coexisting with nitrate without an inhibitory effect and ii) outcompeting denitrifying bacteria for the carbon source, in contrast to the SBR pilot plant where nitrate had an inhibitory effect on EBPR. Copyright © 2012 Society of Chemical Industry 相似文献
73.
Luigi Catuogno Roberto Gassirà Michele Masullo Ivan Visconti 《Information Security Technical Report》2013,17(3):93-104
A smart card is a tamper-resistant miniature computer that performs some basic computations on input a secret information. So far, smart cards have been widely used for securing many digital transactions (e.g., pay television, ATM machines).We focus on the implementation of operating system security services leveraging on smart cards. This very challenging feature allows one to personalize some functionalities of the operating system by simply changing a smart card. Current solutions for integrating smart card features in operating system services require at least a partial execution of some of the operating system functionalities at “user level”. Unfortunately, system functionalities built on top of components lying at both kernel and user levels may negatively affect the overall system security, due to the introduction of multiple points of failure.In this work, we present the design and implementation of SmartK: a framework that integrates features of smart cards uniquely in the Linux kernel. In order to validate our approach, we propose a host of enhancements to the Linux operating system built on top of SmartK: 1) in-kernel clients' authentication with Kerberos; 2) execution of trusted code; 3) key management in secure network filesystems.In particular, we present an experimental Linux OS distribution (SalSA), which addresses the security issues related to downloading packages and to updating an operating system through the Internet. 相似文献
74.
75.
A. P. Kirchheim V. Fernàndez-Altable P. J. M. Monteiro D. C. C. Dal Molin I. Casanova 《Journal of Materials Science》2009,44(8):2038-2045
Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) have been used to study the microstructural
changes and phase development that take place during the hydration of cubic (pure) and orthorhombic (Na-doped) tricalcium
aluminate (C3A) and gypsum in the absence and presence of lime. The results demonstrate that important differences occur in the hydration
of each C3A polymorph and gypsum when no lime is added; orthorhombic C3A reacts faster with gypsum than the cubic phase, forming longer ettringite needles; however, the presence of lime slows down
the formation of ettringite in the orthorhombic sample. Additional rheometric tests showed the possible effects on the setting
time in these cementitious mixes. 相似文献
76.
This article proposes an analytical model for evaluating the number of simultaneous communications that can be sustained by
an ad-hoc network in which the nodes are equipped with fully adaptive smart antennas. The presented mathematical framework
adopts realistic models for the antenna radiation pattern and the channel behavior, and is able to take into account the network
topology and the characteristics of the medium access control (MAC) protocol in the spatial domain. The model is employed
to investigate the impact of the spatial channel model and of the angular spread on network performance. Additionally, this
article examines the influence of the transmission policy of the control and data packets of the MAC layer on the number of
simultaneous communications. 相似文献
77.
Imma Andorrà Sara Landi Albert Mas Braulio Esteve-Zarzoso José M. Guillamón 《Food research international (Ottawa, Ont.)》2010,43(3):773-779
The population dynamics of micro-organisms during grape-must fermentation has been thoroughly studied. However, the main approach has relied on microbiological methods based on plating. This approach may overlook micro-organisms that (i) grow slowly or do not grow well on artificial media or (ii) whose population size is small enough to be detected by regular sampling. Culture-independent methods have been used and compared with the traditional plating method during wine fermentations performed at two different temperatures (13 °C and 25 °C). These methods include a qualitative technique, the DGGE; a semi-quantitative technique, the direct cloning of amplified DNA; and a quantitative technique, the QPCR. The biodiversity observed in the must and at the beginning of fermentation was much higher when DGGE or direct cloning were used. Quantification of the most frequent non-Saccharomyces yeast, Hanseniaspora uvarum and Candida zemplinina, showed that they survived throughout the fermentation process and, specifically, it revealed the quantitatively relevant presence of C. zemplinina until the end of fermentation. 相似文献
78.
79.
Thermally induced protein unfolding/folding processes have been studied on alpha-lactalbumin and alpha-apolactalbumin. Experiments monitored by fluorescence and circular dichroism spectroscopic techniques on alpha-apolactalbumin showed the formation of an intermediate species, whereas in the case of alpha-lactalbumin, this intermediate species was not detected. The presence and resolution of this intermediate species, its spectrum, and the evolution of all conformations during protein unfolding/folding processes were estimated using the multivariate curve resolution-alternating least-squares method. Elucidation of the nature and contribution of the different secondary structure motifs in each of the resolved protein conformations, including the intermediate, was also carried out. Multivariate resolution has shown to be an excellent tool for the complete characterization of all protein conformations involved in folding processes, including intermediate species that cannot be isolated by physical or chemical means. Indeed, it is in the determination and modeling of these intermediates that this chemometric approach outperforms in power and reliability previous methodologies based on simpler measurements and data treatments and fills the void linked to the elucidation and interpretation of complex mechanisms in protein folding processes. 相似文献
80.
Rod Oldehoeft 《The Journal of supercomputing》2002,22(1):5-6