Green Methods for Corrosion Control

Corrosion of metals is a serious environmental problem. Most of the corrosion inhibitors are synthetic chemicals that are hazardous to environments and expensive. Today, there has been an increasing search for green corrosion inhibitors, due to the toxicity of some inhibitors. Green corrosion inhibitors are biodegradable and free of heavy metals or other toxic compounds. There is an intensive effort underway to develop new plant origin corrosion inhibitors for metal subjected to various environmental conditions. Salts of rare earth elements can be also used as inorganic alternative nontoxic corrosion inhibitors. Sol-gel coatings can be recommended as green protective films for metal corrosion. The origin of sol-gel process, its advantages and limitations, and the type of coating method are presented in this chapter, as well as a brief summary of recent literature concerning the use of hybrid inorganic-organic sol-gel and nanostructured sol-gel protective coatings for metal corrosion in different media

Passivity characteristics on Ni(Cr)(Fe)SiB glassy alloys in phosphate solution

AbstractPassivity characteristics of three nickel-metalloids glassy alloys (Ni92.3Si4.5B32, Ni82.3Cr7Fe3Si4.5B3.2 and Ni75.5Cr13Fe4.2Si4.5B2.8) and the immersion time effect on the corrosion resistance were carried out by AC and DC electrochemical methods and SEM and XPS analyses. The study also focused on the effect of H3PO4 concentration and its role on the corrosion rate, passivation ability of nickel base glassy alloys surface. The present investigation revealed (i) corrosion resistance of Cr-free alloy shows pseudo passivity at all examined H3PO4 concentrations, (ii) high corrosion resistance of Cr contains alloys due to the formation of protective layer of chromium oxyhydroxide on the surface which acts as a diffusion barrier against alloy dissolution, (iii) the negative resistance observed in the case Ni75.5Cr13Fe4.2Si4.5B2.8 alloy revealed the sudden transition of metal/solution interface from a state of active dissolution to the passive state

The influence of graphitization catalyst electrode in electrical discharge machining of polycrystalline diamond-finishing condition

Electrical Discharge Machining (EDM) is a non-contact machining process that becomes famous in machining of Polycrystalline Diamond (PCD). The material is typically used as the cutting tools for aerospace and automotive industries. However, low electrical conductivity and high melting temperature of PCD has caused slower EDM process. This investigation purposely designed to investigate the influence of different types of electrode which are Copper (ordinary electrode) and Copper-Nickel (newly proposed graphitization catalyst electrode) on EDM performance of MRR and Ra. Interestingly the newly proposed electrode gave positive impact to the investigated performance indication. Cu-Ni electrode recorded 35% better in MRR than the Cu electrode, though with higher short-circuiting rate. Cu-Ni also provided the lowest Ra value with 10% better than the best Ra produced by Cu electrode. This phenomenon occurred as due to the high interaction between the catalyst materials of nickel and diamond which supported by the qualification data provided in this investigation

Impact of cropping system diversification on productivity and resource use efficiencies of smallholder farmers in south-central Bangladesh: a multi-criteria analysis

Diversification of smallholder rice-based cropping systems has the potential to increase cropping system intensity and boost food security. However, impacts on resource use efficiencies (e.g., nutrients, energy, and labor) remain poorly understood, highlighting the need to quantify synergies and trade-offs among different sustainability indicators under on-farm conditions. In southern coastal Bangladesh, aman season rice is characterized by low inputs and low productivity. We evaluated the farm-level impacts of cropping system intensification (adding irrigated boro season rice) and diversification (adding chili, groundnut, mungbean, or lathyrus) on seven performance indicators (rice equivalent yield, energy efficiency, partial nitrogen productivity, partial potassium productivity, partial greenhouse gas footprint, benefit-cost ratio, and hired labor energy productivity) based on a comprehensive survey of 501 households. Indicators were combined into a multi-criteria performance index, and their scope for improvement was calculated by comparing an individual farmer’s performance to top-performing farmers (highest 20%). Results indicate that the baseline system (single-crop aman season rice) was the least productive, while double cropped systems increased rice equivalent yield 72–217%. Despite gains in productivity, higher cropping intensity reduced resource use efficiencies due to higher inputs of fertilizer and energy, which also increased production costs, particularly for boro season rice. However, trade-offs were smaller for diversified systems including legumes, largely owing to lower N fertilizer inputs. Aman season rice had the highest multi-criteria performance index, followed by systems with mungbean and lathyrus, indicating the latter are promising options to boost food production and profitability without compromising sustainability. Large gaps between individual and top-performing farmers existed for each indicator, suggesting significant scope for improvement. By targeting indicators contributing most to the multi-criteria performance index (partial nitrogen productivity, energy efficiency, hired labor energy productivity), results suggest further sustainability gains can be achieved through future field research studies focused on optimizing management within diversified systems

The predictors of adolescents’ smoking in Egypt, the global youth tobacco survey findings

This study secondary analysed the last Global Youth Tobacco Survey (GYTS) implemented in Egypt which is a cross-sectional school-based survey used self-administered questionnaire to research smoking among a national representative sample of (2,141) adolescents aged 13–15 years. The study identified that male adolescents are more likely to smoke than female adolescents in Egypt. The likelihood of adolescents’ smoking in Egypt was significantly associated with age; low educational level of fathers; having no weekly pocket of money; poor self-confidence to refuse friends’ smoking offers; absence of restriction on selling cigarettes to adolescents near their schools; and observing teachers’ smoking inside schools. Whereas accessing information, through schools, about smoking consequences prevents adolescents’ smoking. Adolescence is critical period for experimenting and continue smoking. The study identified some personal, parenteral, and school related factors that influence adolescents’ smoking in Egypt. These factors should be considered in designing smoking prevention program that targets adolescents

DETERMINATION CADMIUM, LEAD AND ZINC IN HUMAN HAIR BY USING FLAME ATOMIC ABSORPTION SPECTROMETRY (FAAS)

The heavy metals mean serious hazard in environmental pollution. Some of them are vital for many organisms in a low concentration, however the others ought to be poisonous at low concentrations, too. This paper gives an example for the correlation of the attention in human hair and in the environment of different heavy metals. Human hair (n=50) Volunteers (35 males and 15 females) of different age groups between 1 to 57 years samples were collected in Al – Ajailat, Libya. Hair samples were analyzed for heavy metals (Cd, Pb and Zn) by Flame Atomic Absorption Spectrophotometric technique (FAAS). The results showed that the samples concentrations ranged between 0.0001 and 0.3840 mg.kg−1 for cadmium, followed by zinc between 68.99 mg kg−1 and 225mg. kg−1while lead was between 0.632 mg kg−1 and 7.708mg. Kg−1. The results indicated that metal concentrations in male samples varied based on age, such that age group 33-43 years had the highest zinc concentration (206.2±11.6 mg/kg), and age group 1-10 years had the highest Cd (0.384±0.01 mg/kg) and Pb (1.929±0.05 mg/kg) concentrations. while, the cadmium and lead contents in children’s hair samples of both sexes was higher than compared to the values available in some countries. The difference between male and female concentration could be due to individual differences in exposure to heavy metal load as a result of habitual or environmental factors

Malocclusion, psycho-social impacts and treatment need: A cross-sectional study of Tanzanian primary school-children

<p>Abstract</p> <p>Background</p> <p>studies on the relationship between children's malocclusion and its psycho-social impacts are so far largely unexplored in low-income countries. This study aimed to assess the prevalence of malocclusion, reported dental problems and dissatisfaction with dental appearance among primary school children in Tanzania. The relationship of dissatisfaction with socio-demographic characteristics, clinically defined malocclusion and psychosocial impacts of dental anomalies was investigated. Orthodontic treatment need was estimated using an integrated socio-dental approach.</p> <p>Method</p> <p>One thousand six hundred and one children (mean age 13 yr) attending primary schools in the districts of Kinondoni and Temeke completed face to face interviews and a full mouth clinical examination. The survey instrument was designed to measure a Kiswahili translated and culturally adapted Child Oral Impact on Daily Performance (Child-OIDP) frequency score, reported dental problems, dissatisfaction with dental appearance/function and socio-demographic characteristics.</p> <p>Results</p> <p>The prevalence of malocclusion varied from 0.9% (deep bite) to 22.5% (midline shift) with a total of 63.8% having at least one type of anomaly. Moderate proportions of children admitted dental problems; ranging from 7% (space position) to 20% (pain). The odds ratio of having problems with teeth position, spaces, pain and swallowing if having any malocclusion were, respectively 6.7, 3.9, 1.4 and 6.8. A total of 23.3% children were dissatisfied with dental appearance/function. Children dissatisfied with their dental appearance were less likely to be Temeke residents (OR = 0.5) and having parents of higher education (OR = 0.6) and more likely to reporting problem with teeth position (OR = 4.3) and having oral impacts (OR = 2.7). The socio-dental treatment need of 12% was five times lower than the normative need assessment of 63.8%.</p> <p>Conclusion</p> <p>Compared to the high prevalence of malocclusion, psycho social impacts and dissatisfaction with appearance/function was not frequent among Tanzanian schoolchildren. Subjects with malocclusion reported problems most frequently and malocclusion together with other psycho-social impact scores determined children's satisfaction with teeth appearance- and function.</p