Structural and properties of Zn-Al2O3-SiC nano-composite coatings by direct electrolytic process

In this paper, Zn-SiC and Zn-Al2O3-SiC composite coating were fabricated by electrodeposition technique from sulfates bath. The resulting composite coating was carried out by adding Al2O3/SiC particulate to a zinc-containing bath. The properties of the composite coating were investigated by SEM equipped with EDS, XRD, and AFM. The electrochemical behavior of the coating alloy was evaluated in 3.65 % NaCl with linear polarization technique and mechanically examined by durascan microhardness tester. The morphology of the thermal treated coatings at 400 °C in 6 h was viewed with high optical microscope (OPM). The results show hardness, thermal stability, and anti-corrosion properties of Zn-Al2O3-SiC were improved significantly as against Zn- SiC coating matrixes. This was attributed to dispersive strengthening effect and grain induced effort of Al2O3/SiC particulate. The decrease in corrosion and thermal stability at 15 g/L of SiC concentration may be as a result of agglomeration and the superimposed particle in the plating bath

Internet service providers responsibilities in botnet mitigation: a Nigerian perspective

Botnet-based attack is dangerous and extremely difficult to overcome as all the primary mitigation methods are passive and limited in focus. A combine efforts of internet service providers (ISPs) are better guides since they can monitor the traffic that traverse through their networks. However, ISPs are not legally banded to this role and may not view security as a primary concern. Towards understudying the involvement of ISPs in Botnet mitigation in Nigeria, this study elicited and summarized mitigation measures from scientific literatures to create a reference model which was validated by structured interview. Although, ISPs role is seen to be voluntary and poorly incentivized, the providers still take customers security very serious but concentrate more on the preventive and notification measures

Multifaceted incorporation of Zn-Al2O3/Cr2O3/SiO2 nanocomposite coatings: anti-corrosion, tribological, and thermal stability

Nano-sized particle incorporation into metal matrix has gained worldwide acceptance. Al2O3, Cr2O3, and SiO2 nanoparticles have been co-deposited with Zn using electrodeposition process to produce advanced alloy. The coatings were characterized using SEM/EDX and XRD. The mechanical properties of the coatings were studied using microhardness indenter and dry abrasive wear tester. Zn-10 g/L Cr2O3 nanocomposite exhibited the highest microhardness of 228 HVN; Zn-5 g/L Al2O3 nanocomposite possessed the highest corrosion resistance and lowest wear loss. Zn-5 g/L SiO2 nanocomposite showed good stability against other composite coatings. The incorporation of the Al2O3, Cr2O3, and SiO2 shows grain refinement and modify orientation on Zn matrix

Effect of WO3 Nanoparticle Loading on the Microstructural, Mechanical and Corrosion Resistance of Zn Matrix/TiO2-WO3 Nanocomposite Coatings for Marine Application

In this study, for marine application purposes, we evaluated the effect of process parameter and particle loading on the microstructure, mechanical reinforcement and corrosion resistance properties of a Zn-TiO2-WO3 nanocomposite produced via electrodeposition. We characterized the morphological properties of the composite coatings with a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS). We carried out mechanical examination using a Dura Scan hardness tester and a CERT UMT-2 multi-functional tribological tester. We evaluated the corrosion properties by linear polarization in 3.5% NaCl. The results show that the coatings exhibited good stability and the quantitative particle loading greatly enhanced the structural and morphological properties, hardness behavior and corrosion resistance of the coatings. We observed the precipitation of this alloy on steel is greatly influenced by the composite characteristics

Hungary and the European Union: the political implications of societal security promotion

Hungary's constitutional commitment to support kin-nationals beyond its borders (nation policy) has been a central feature of its post-1989 foreign policy and highlights a particularly important national security concern—the societal security of national identity, culture, language and tradition. This article examines Hungary's societal security concerns and the policy methods it utilises, including its EU membership and the promotion of minority rights at the European level, to help combat these concerns. It is suggested that Hungary has found it somewhat difficult to balance its societal security policy objective with internal economic demands on its welfare system and its external foreign policy objective to maintain good neighbourly relations. This article also notes that Hungary's attempts to Europeanise, or rather 'EU-ise', minority and ethnic rights issues as a means to enhance societal security for the Hungarian nation has certain political consequences for the EU. This suggests that societal security provision is an issue that cannot be overlooked when trying to understand the longer-term implications of EU eastern enlargement

Corrosion Resistance of AA6063-Type Al-Mg-Si Alloy by Silicon Carbide in Sodium Chloride Solution for Marine Application

The present work focused on corrosion inhibition of AA6063 type Al-Mg-Si alloy in sodium chloride (NaCl) solution with a silicon carbide inhibitor, using the potentiodynamic electrochemical method. The aluminium alloy surface morphology was examined, in the as-received and as-corroded in the un-inhibited state, with scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS). The results obtained via linear polarization indicated a high corrosion potential for the unprotected as-received alloy. Equally, inhibition efficiency as high as 98.82% at 10.0 g/v silicon carbide addition was obtained with increased polarization resistance (Rp), while the current density reduced significantly for inhibited samples compared to the un-inhibited aluminium alloy. The adsorption mechanism of the inhibitor aluminium alloy follows the Langmuir adsorption isotherm. This shows that the corrosion rate of aluminium alloy with silicon carbide in NaCl environment decreased significantly with addition of the inhibito

Chemical interaction, interfacial effect and the microstructural characterization of the induced zinc–aluminum–Solanum tuberosum in chloride solution on mild steel

In this study, we report the effect of Solanum tuberosum (ST) as a strong additive on the morphological interaction, wear, and hardness properties of electroplated zinc coating in chloride bath solutions. The structural and the mechanical behavior of the Zn–Al–ST coating were studied and compared with the properties of Zn coatings. Characterization of the electrodeposited coatings were carried out using scanning electron microscopy, energy dispersive spectrometer, AFM, and X-ray diffraction techniques. The adhesion between the coatings and substrate was examined mechanically using hardness and wear techniques. From the results, amorphous Zn–Al–ST coatings were effectively obtained by electrodeposition using direct current. The coating morphology was revealed to be reliant on the bath composition containing strong leveling additives. From all indications, ST content contribute to a strong interfacial surface effect leading to crack-free and better morphology, good hardness properties, and improved wear resistance due to the precipitation of Zn2Si and Zn7Al2Si3. Hence, addition of ST is beneficial for the structural strengthening, hardness, and wear resistance properties of such coatings

Dynamics of dental evolution in ornithopod dinosaurs.

Ornithopods were key herbivorous dinosaurs in Mesozoic terrestrial ecosystems, with a variety of tooth morphologies. Several clades, especially the 'duck-billed' hadrosaurids, became hugely diverse and abundant almost worldwide. Yet their evolutionary dynamics have been disputed, particularly whether they diversified in response to events in plant evolution. Here we focus on their remarkable dietary adaptations, using tooth and jaw characters to examine changes in dental disparity and evolutionary rate. Ornithopods explored different areas of dental morphospace throughout their evolution, showing a long-term expansion. There were four major evolutionary rate increases, the first among basal iguanodontians in the Middle-Late Jurassic, and the three others among the Hadrosauridae, above and below the split of their two major clades, in the middle of the Late Cretaceous. These evolutionary bursts do not correspond to times of plant diversification, including the radiation of the flowering plants, and suggest that dental innovation rather than coevolution with major plant clades was a major driver in ornithopod evolution