To protect materials from surface degradations such as wear, corrosion, and thermal flux, a wide variety of materials can be deposited on the materials by several spraying processes. This paper examines and compares the microstructure and high-temperature corrosion of Ni-20Cr coatings deposited on T22 boiler steel by high velocity oxy-fuel (HVOF), detonation gun spray, and cold spraying techniques. The coatings’ microstructural features were characterized by means of XRD and FE-SEM/EDS analyses. Based upon the results of mass gain, XRD, and FE-SEM/EDS analyses it may be concluded that the Ni-20Cr coating sprayed by all the three techniques was effective in reducing the corrosion rate of the steel. Among the three coatings, D-gun spray coating proved to be better than HVOF-spray and cold-spray coatings. 相似文献
4G wireless networks will integrate heterogeneous technologies such as Wireless LAN and third generation (3G) cellular networks and have the capability to offer various services at any time as per user requirements, anywhere with seamless interoperability at affordable cost. One important challenge in such a heterogeneous wireless environment is to enable network selection mechanisms in order to keep the mobile users always best connected anywhere and at any time. In this paper, a multi-criteria access network selection algorithm is proposed in Worldwide Interoperability for Microwave Access–Wireless Fidelity environment, in order to facilitate the provision of high quality services and at the same time to satisfy different types of user service level agreements. Analytical hierarchy process (AHP) and grey relational analysis (GRA) methods are applying for optimal access network selection. The proposed methodology combines the AHP to decide the relative weights of criteria set according to network’s performance, as well as the GRA to rank the network alternatives. The advantages of the GRA method are that the results are based on the original data, the calculations are simple and straightforward, and finally it is one of the best methods to make decision under heterogeneous wireless network environment. 相似文献
In fifth generation heterogeneous network, small cell is developed to compensate the growing demand for mobile data services. Due to the smaller size of cell, users have a short duration of connection, however, the user may also have the need of handoff frequently. At the time of handoff, different networks are available with different data rate and different other parameters. So, there is the need of frequent selection for the optimal network. In this paper, a utility-aware optimization algorithm has been proposed for network selection in a heterogeneous environment of Wi-Fi, WiMAX, WLAN, LTE, UMTS, and GPRS network. The weight factor is proposed for modified Jaya algorithm which is calculated by the analytical hierarchical process, standard deviation, and entropy method. Different applications are considered such as video, voice, web browsing and email transfer in which available bandwidth, packet jitter, packet loss, cost per byte are taken as dominant attributes, respectively. According to the dominant factor, different networks are selected for different applications because the requirement of all applications cannot be fulfilled by one network. Finally, the proposed algorithm is compared with multi-attribute decision making algorithms and game theory and accuracy of the proposed algorithm is calculated. The accuracy of proposed algorithm is higher as compared to the other algorithms and at the same time, this algorithm requires less computation which can further reduce the handoff latency and failure probability. Hence, the performance of handoff can be improved by using modified Jaya algorithm.
Application-specific integrated circuit (ASIC) design is too risky and prohibitively expensive for many applications. This trend, combined with increasing silicon capability on a die, is fueling the emergence of application-specific programmable architectures. This focus on architecture design for network processors has made programming them an arduous task. Current network processors require in-depth knowledge of the architecture just to begin programming the device. However, for network processors to succeed, programmers must efficiently implement high-performance applications on them. Writing high-performance code for modern network processors is difficult because of their complexity. NP-Click is a simple programming model that permits programmers to reap the benefits of a domain specific language while still allowing for target-specific optimizations. Results for the Intel IXP1200 indicate that NP-Click delivers a large productivity gain at a slight performance expense. 相似文献
Multimedia Tools and Applications - Bowel cancer is one of the most common cancers as stated in the bowel cancer cases statistics. The proposed technique is to recognize the pattern of tissue... 相似文献
Pure aluminum reinforced with carbon nanotube (CNT) composites have been prepared by high energy attritor milling up to 48 hrs. Differential Scanning Calorimetry (DSC) has been carried out to investigate apparent activation energy and order of the reaction between carbon nanotubes and aluminum by Kissinger equation and Crane equation under non-isothermal conditions. The DSC results clearly reveal that an exothermic reaction occurs before the melting of aluminum. The effect of milling time on the initiation of this exothermic reaction has been studied. The peak temperature of the reaction of carbon nanotubes and aluminum is found to depend on the heating rate during the continuous heating. Apparent activation energy was found to get doubled after milling for 36 hrs compared to 24 hrs milled samples. The mechanism of the reaction kinetics which depends on reaction order is instantaneous nucleation and one dimensional growth for both samples. Formation of Al4C3 was confirmed by X-ray diffraction (XRD) of as-milled powders and after performing DSC of the milled powders. 相似文献
The involvement of otolith organs in motion sickness has long been debated; however, equivocal findings exist in literature. The present study thus aimed at evaluating the otolith functioning in individuals with motion sickness. Cervical and ocular vestibular evoked myogenic potentials were recorded from 30 individuals with motion sickness, 30 professional drivers and 30 healthy individuals. The results revealed no significant difference in latencies and amplitudes between the groups (p>0.05). Nonetheless, thresholds were significantly elevated and inter-aural asymmetry ratio significantly higher in motion sickness susceptible group (p < 0.001) for both the potentials. All the individuals in the motion sickness group had high asymmetry ratio at least on one of the two potentials. Thus, reduced response and/or asymmetric otolithic function seem the likely reasons behind motion sickness susceptibility. 相似文献
Current anti-malware tools have proved to be insufficient in combating ever-evolving malware attacks and vulnerability exploits due to inevitable vulnerabilities present in the complex software used today. In addition, the performance penalty incurred by anti-malware tools is magnified when security approaches designed for desktops are migrated to modern mobile devices, such as tablets and laptops, due to their relatively limited processing capabilities and battery capacities. In this paper, we propose a fine-grained anomaly detection defense framework that offers a cost-efficient way to detect malicious behavior and prevent vulnerability exploits in resource-constrained computing platforms. In this framework, a trusted third party (e.g., the publisher) first tests a new application by running it in a heavily monitored testing environment that emulates the target system and extracts a behavioral model from its execution paths. Extensive security policies are enforced during this process. In case of a violation, the program is denied release to the user. If the application passes the tests, the user can download the behavioral model along with the tested application binary. At run-time, the application is monitored against the behavioral model. In the unlikely event that a new execution path is encountered, conservative but lightweight security policies are applied. To reduce overhead at the user end, the behavioral model may be further reduced by the publisher through static analysis. We have implemented the defense framework using a netbook with the Intel Atom processor and evaluated it with a suite of 51 real-world Linux viruses and malware. Experiments demonstrate that our tool achieves a very high coverage (98 %) of considered malware and security threats. The four antivirus tools we compare our tool against were found to have poor virus coverage, especially of obfuscated viruses. By removing safe standard library blocks from the behavioral model, we reduce the model size by 8.4\(\times \) and the user’s run-time overhead by 23 %. 相似文献