Wear and corrosion resistant properties of electrodeposited Ni composite coating containing Al2O3-TiO2 composite powder

Electrodeposited Ni composite coatings containing ceramic particles have been widely investigated due to their improved mechanical, wear and corrosion resistant properties over plain nickel coatings. The application of one of the most widely studied plasma spray powder, Al2O3–13 wt-%TiO2, has not been explored in electrodeposited nickel composites. In the present study, Ni/Al2O3–13 wt-%TiO2 coatings have been electrodeposited using physically mixed commercial Al2O3 and TiO2 powders. The microhardness, wear and corrosion resistant properties of the coatings have been investigated. It was found that the area fraction of particles incorporated in the nickel matrix was very high at lower current density, and the corresponding composite coating exhibited a maximum microhardness (∼580 HK). Interestingly, corrosion resistance of Ni/Al2O3–13 wt-%TiO2 composite coating was similar to that reported for Ni/TiO2. The wear behaviour of Ni/Al2O3–13 wt-%TiO2 coating was in between Ni/Al2O3 and Ni/TiO2 coatings and thus exhibited a synergistic effect of the properties of Al2O3 and TiO2 powders

Reclamation of thermal power plant waste as a distributed phase in electrodeposited Ni composite coating

In the exploration for newer and inexpensive distributed phases that can be used in electrodeposited Ni-composite coatings, cenosphere particles which are one of the constituents of fly ash, the waste product of thermal power plants has been explored as a potential candidate material. An attempt was made to prepare electrodeposited Nicenosphere composite coating. The as-received cenosphere particles could be codeposited only after reducing the particle size by ball milling. The loading of cenosphere particles in the Ni-sulphamate bath was varied (25, 75 and 100 g L−1) and a maximum microhardness of 430 HK at 50 gF load was obtained for the coating deposited from 100 g L−1 cenosphere containing bath. The Ni-cenosphere composite coating with higher microhardness exhibited lower wear rate. Thus cenosphere, a waste product from thermal power plants is a potential candidate for a greener surface engineering strategy for improving the wear resistance of electrodeposited Ni composite coating

Fabrication of Superhydrophobic Zinc Stearate Hierarchical Surfaces from Different Precursors

The fabrication of zinc stearate superhydrophobic hierarchical surfaces from two precursors by a simple wet chemical route and its wettability is reported. The zinc stearate coatings were prepared from a single pot using ethanolic solutions of zinc acetate/zinc nitrate and stearic acid. The coatings were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, water contact angle, and sliding angle measurements. The coatings obtained from zinc acetate precursor showed superhydrophobicity (WCA >150°) even at lower precursor concentrations. The morphology of the coatings varied with the nature as well as the concentration of the precursors

In-vitro corrosion studies of plasma sprayed hydroxyapatite coatings fabricated from coprecipitation synthesized powder

Plasma sprayed bioactive hydroxyapatite (HAp) implants on Ti-6Al-4V substrates have been widely used in load-bearing applications because of their biocompatibility and their intimate contact with bone. In the present study, plasma sm. The present paper discusses detailed corrosion behavior of uncoated and hydroxyapatite coated Ti-6Al-4V in simulated body fluid (Hanks` solution) condition. The HAp coated sample exhibited a smoother anodic curve when compared to uncoated substrate suggesting an improved passive nature of the coated surface. The icorr values for the uncoated and HAP coated samples were found to be 20 μA cm-2 and 14 μA cm-2 respectively. Electrochemical impedance spectroscopy studies showed that the HAp coating applied on to the Ti-6Al-4V alloy does not degrade the corrosion protection of the surface but instead offers an improvement to it.m. HAp coating was deposited on Ti-6Al-4V substrate using atmospheric air plasma spraying system. The as synthesized powder exhibited 97% crystallinity, whereas the coating exhibited a crystallinity of 76%. The coating thickness was ~100 µm and it consisted of mostly fully melted regions and unmelted/partially melted regions. The coating exhibited a surface roughness of 5.7 prayable grade hydroxyapatite powder was prepared by co-precipitation technique using mixture of precipitating agents and avoiding agglomeration process like spray drying. The powder possessed good flowability and exhibited an average agglomerated size of 8

Non-solvolytic synthesis of aqueous soluble TiO2 nanoparticles and real-time dynamic measurements of the nanoparticle formation.

Highly aqueously dispersible (soluble) TiO2 nanoparticles are usually synthesized by a solution-based sol-gel (solvolysis/condensation) process, and no direct precipitation of titania has been reported. This paper proposes a new approach to synthesize stable TiO2 nanoparticles by a non-solvolytic method - direct liquid phase precipitation at room temperature. Ligand-capped TiO2 nanoparticles are more readily solubilized compared to uncapped TiO2 nanoparticles, and these capped materials show distinct optical absorbance/emission behaviors. The influence of ligands, way of reactant feeding, and post-treatment on the shape, size, crystalline structure, and surface chemistry of the TiO2 nanoparticles has been thoroughly investigated by the combined use of X-ray diffraction, transmission electron microscopy, UV-visible (UV-vis) spectroscopy, and photoluminescence (PL). It is found that all above variables have significant effects on the size, shape, and dispersivity of the final TiO2 nanoparticles. For the first time, real-time UV-vis spectroscopy and PL are used to dynamically detect the formation and growth of TiO2 nanoparticles in solution. These real-time measurements show that the precipitation process begins to nucleate after an initial inhibition period of about 1 h, thereafter a particle growth occurs and reaches the maximum point after 2 h. The synthesis reaction is essentially completed after 4 h.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Interactions among genes in the ErbB-Neuregulin signalling network are associated with increased susceptibility to schizophrenia

<p>Abstract</p> <p>Background</p> <p>Evidence of genetic association between the NRG1 (Neuregulin-1) gene and schizophrenia is now well-documented. Furthermore, several recent reports suggest association between schizophrenia and single-nucleotide polymorphisms (SNPs) in ERBB4, one of the receptors for Neuregulin-1. In this study, we have extended the previously published associations by investigating the involvement of all eight genes from the ERBB and NRG families for association with schizophrenia.</p> <p>Methods</p> <p>Eight genes from the ERBB and NRG families were tested for association to schizophrenia using a collection of 396 cases and 1,342 blood bank controls ascertained from Aberdeen, UK. A total of 365 SNPs were tested. Association testing of both alleles and genotypes was carried out using the fast Fisher's Exact Test (FET). To understand better the nature of the associations, all pairs of SNPs separated by ≥ 0.5 cM with at least nominal evidence of association (<it>P </it>< 0.10) were tested for evidence of pairwise interaction by logistic regression analysis.</p> <p>Results</p> <p>42 out of 365 tested SNPs in the eight genes from the ERBB and NRG gene families were significantly associated with schizophrenia (<it>P </it>< 0.05). Associated SNPs were located in ERBB4 and NRG1, confirming earlier reports. However, novel associations were also seen in NRG2, NRG3 and EGFR. In pairwise interaction tests, clear evidence of gene-gene interaction was detected for NRG1-NRG2, NRG1-NRG3 and EGFR-NRG2, and suggestive evidence was also seen for ERBB4-NRG1, ERBB4-NRG2, ERBB4-NRG3 and ERBB4-ERBB2. Evidence of intragenic interaction was seen for SNPs in ERBB4.</p> <p>Conclusion</p> <p>These new findings suggest that observed associations between NRG1 and schizophrenia may be mediated through functional interaction not just with ERBB4, but with other members of the NRG and ERBB families. There is evidence that genetic interaction among these loci may increase susceptibility to schizophrenia.</p

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good