CORROSION PERFORMANCE OF 1014 MILD AND 304 STAINLESS STEELS IN ACIDIC MEDIA

Corrosion is a degradation of metallic materials under the action of the environment which requires oxygen and moisture to occur. This research work determined the corrosion performance of 1014 low carbon and 304 austenitic stainless steels in different concentration of acidic media. Corrosion tests were carried out using gravimetric technique. One hundred and eighty samples of the metals were prepared and immersed in containers of sulphuric acid (H2SO4), hydrochloric acid (HCl) and nitric acid (HNO3) at 1, 2 & 3 M. The samples were then removed every three days for a period of 15 days to measure the weight loss. These were used to calculate the corrosion rates. The chemical analysis was determined using an Energy Dispersive X-ray (EDX).  Scanning Electron Microscope (SEM) was used to determine the texture of the samples. The results showed that the corroded samples had pitting corrosion damage and cracks propagated generally on the sample surfaces. The corrosion rates of the samples increased with increase in molarities of the reagents, Stainless steel samples had the least corroded surfaces. The study concluded that the higher the level of concentration of acidic media (1 to 3 M), the higher the corrosion rates of samples in increasing order of HNO3, HCl and H2SO4 especially for mild steel sample (4.35 to 17.90, 0.21 to 2.90 and 10.37 to 0.64 mm/y) after 360 hours of immersion respectively. &nbsp

Health Problems and Health Seeking Behaviour of Hospital Cleaners in a Tertiary Health Facility in South West Nigeria

This study aimed to determine the prevalent health problems and also investigate the health seeking behavior among hospital cleaners of Federal Medical Center, Owo, Ondo State. Nigeria. A cross-sectional study of 249 hospital cleaning staff was conducted. Semi-structured interviewer administered questionnaires were used to obtain information. Descriptive statistics were done and associations were explored with the chi square test at 5% level of significance. The mean age of respondent was 34 ±7 years, 142(57.0%) attended secondary school. The workplace health problems of the cleaning staff in the month preceding the study included low back pains 63.1%, muscular and joint pains 38.6% and skin rashes 14.9%, 15.7% had eye problems. The chronic health problems reported among the cleaners were hypertension 5.6%, asthma (0.8%) and epilepsy (0.4%). Some ( 3.2%) of the respondents did not seek healthcare at FMC, Owo because they felt they were not being cared for while 3.6% believed they were healthy and others 4.4% believed the services were too expensive. Like other health workers, hospital cleaners as shown in this study, also have health needs which must be met. Services of the hospital can be made available to the cleaners at subsidized costs. DOI: 10.5901/ajis.2014.v3n6p18

Rare earth interstitial-complexes in Ge : hybrid density functional studies

Please read abstract in the article.The National Research Foundation (NRF) of South Africa [98961]http://www.elsevier.com/locate/nimb2018-10-15hj2017Physic

Rare earth substitutional impurities in germanium : a hybrid density functional theory study

Please read abstract in the article.The National Research Foundation (NRF) of South Africa [(UID) 98961]http://www.elsevier.com/locate/nimb2018-10-15hj2017Physic

Induced defect levels of P and Al vacancy-complexes in 4H-SiC : a hybrid functional study

Please read abstract in the article.The National Research foundation (NRF) of South Africa (Grant specific unique reference number (UID) 98961).http://www.elsevier.com/locate/mssp2020-01-01hj2018Physic

Electrical characterization of defects induced by electron beam exposure in low doped n-GaAs

We have used deep level transient spectroscopy (DLTS) and Laplace DLTS (L-DLTS) to characterize the electrically active point defects introduced in n-type gallium arsenide by electron beam exposure prior to Schottky metallization. The GaAs crystals were exposed to incident electrons at sub-threshold energies which are deemed low and insufficient to form defects through ion solid interactions. DLTS revealed a set of electron traps different from those commonly observed in n-GaAs after particle irradiation. These different signatures from the same radiation type suggest that different mechanisms are responsible for defect formation in the two electron irradiation processes. An analysis of the conditions under which the defects were formed was done to distil a number of possible defect formation mechanisms using the experimental evidence obtained.The South African National Research Foundation (NRF) and the University of Pretoria.http://www.elsevier.com/locate/nimb2018-10-30Physic

Identification of active sites on supported metal catalysts with carbon nanotube hydrogen highways

Catalysts consisting of metal particles supported on reducible oxides exhibit promising activity and selectivity for a variety of current and emerging industrial processes. Enhanced catalytic activity can arise from direct contact between the support and the metal or from metal-induced promoter effects on the oxide. Discovering the source of enhanced catalytic activity and selectivity is challenging, with conflicting arguments often presented based on indirect evidence. Here, we separate the metal from the support by a controlled distance while maintaining the ability to promote defects via the use of carbon nanotube hydrogen highways. As illustrative cases, we use this approach to show that the selective transformation of furfural to methylfuran over Pd/TiO2 occurs at the Pd-TiO2 interface while anisole conversion to phenol and cresol over Cu/TiO2 is facilitated by exposed Ti3+ cations on the support. This approach can be used to clarify many conflicting arguments in the literatureWe acknowledge financial support from the National Science Foundation, Grant CAREER1653935. Use of the Advanced Photon Source is supported by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences, under Contract DE-AC02-06CH11357. MRCAT operations are supported by the Department of Energy and the MRCAT member institutions. E.C.W. and J.T.M. were supported in part by Center for Innovative Transformation of Alkane Resources (CISTAR) by the National Science Foundation under Cooperative Agreement No. EEC-1647722. Open access fees fees for this article provided whole or in part by OU Libraries Open Access Fund.Ye

The effects of high-energy proton irradiation on the electrical characteristics of Au/Ni/4H-SiC Schottky barrier diodes

Please read abstract in the article.The University of Pretoria and the National Research Foundation (NRF) of South Africa, Grant number 98961.http://www.elsevier.com/locate/nimb2018-10-15hj2017Physic

Differences and Commonalities in Physical, Chemical and Mineralogical Properties of Zanzibari Geophagic Soils

The function of human geophagy has long been questioned. We sought to test hypotheses concerning its potential physiological effects through analysis of soils and patterns in geophagy behavior. Eleven samples of geophagic soils consumed by pregnant women on Pemba Island, Zanzibar, Tanzania, were characterized according to their color, texture, major element chemistry, trace element chemistry, bulk mineralogy, and clay mineralogy. An epidemiological study (N = 2367) and ethnographic interviews (N = 57) on Pemba yielded information about geophagic behaviors and socio-demographic and biological characteristics of those who consumed earth. The soils varied widely in color, ranging from light red to white through various shades of brown and yellow, and texture ranged from clay to sand. Major element chemistry of the soils also varied greatly; most were low in Fe and Ca. Trace elements, whether of biological or non-biological significance, were uniformly low when compared with normal ranges of mineral soils. The sole commonality among the samples is that all clay fractions were dominated by a kaolin mineral: kaolinite, halloysite, or a mixture of both. Geophagy behavior also varied greatly, with one major exception: a greater proportion of pregnant women (7.1%) and young children (4.5%) consumed earth than non-pregnant women (0.2%) or men (0%). The presence of kaolin mineral in all samples, its palliative and detoxifying properties, and the highest prevalence of geophagy among those most biologically vulnerable suggest that geophagy may be a protective behavior

Determination of neo- and d-chiro-Inositol Hexakisphosphate in Soils by Solution 31P NMR Spectroscopy

The inositol phosphates are an abundant but poorly understood group of organic phosphorus compounds found widely in the environment. Four stereoisomers of inositol hexakisphosphate (IP6) occur, although for three of these (scyllo, flea, and D-chiro) the origins, dynamics, and biological function remain unknown, due in large part to analytical limitations in their measurement in environmental samples. We synthesized authentic neo- and n-chiro-IP6 and used them to identify signals from these compounds in three soils from the Falkland Islands. Both compounds resisted hypobromite oxidation and gave quantifiable P-31 NMR signals at delta = 6.67 ppm (equatorial phosphate groups of the 4-equatorial/2-axial conformer of neo-IP6) and delta = 6.48 ppm (equatorial phosphate groups of the 2-equatorial/4-axial conformer of D-chiro-IP6) in soil extracts. Inositol hexakisphosphate accounted for 46-54% of the soil organic phosphorus, of which the four stereoisomers constituted, on average, 55.9% (myo), 32.8% (scyllo), 6.1% (neo), and 5.2% (n-chiro). Reappraisal of the literature based on the new signal assignments revealed that neo- and D-chiro-IP6 occur widely in both terrestrial and aquatic ecosystems. These results confirm that the inositol phosphates can constitute a considerable fraction of the organic phosphorus in soils and reveal the prevalence of neo- and D-chiro-IP6 in the environment. The hypobromite oxidation and solution P-31 NMR spectroscopy procedure allows the simultaneous quantification of all four IP6 stereoisomers in environmental samples and provides a platform for research into the origins and ecological significance of these enigmatic compounds