Search results

This paper seeks to study the corrosion rate (CR) of Al 6063 in aqueous solutions containing food additives, namely ascorbic, citric and tartaric acids with/without chloride ions.

Chemical and electrochemical measurements were used to study the CR of Al 6063 in aerated aqueous solutions. Chemical measurements include weight loss (WL) and atomic absorption (AA). The surface morphology of Al 6063 was studied using scanning electron microscope connected with energy dispersion X‐Ray (EDX). Electrochemical measurements were made using a potentiostat/galvanostat; the effect of pH, temperature and immersion time was studied.

AA gave comparable results to that of WL. EDX results showed the depletion of Mg and Fe from the Al 6063 to carboxylic acid solutions w/without NaCl. From electrochemical measurements, it was found that addition of chloride ions to carboxylic acids increased the CR of Al 6063 especially at low pH and high temperatures but it reduced the CR at long immersion times.

Aluminum (Al) is now known to be a neurotoxin agent yet Al cook wares are widely used in different countries. The acids used in this study are food additives which implies that the Al cook wares may corrode in food containing these acids and other carboxylic acids depending on pH, temperature and the presence of other additives.

AA gave comparable results to that of WL, which shows that it may be used to evaluate leaching metal ions in μg levels or less in corrosion measurements.

The purpose of this paper is to identify the obstacles to the availability of suitable housing units for various socioeconomic segments of society with an emphasis on single-family homes, which is the most preferred housing type in the Saudi society.

To achieve the aim of this paper, the Delphi method was used to explore the experts’ opinions on the most important obstacles.

The findings of the study underline 17 different obstacles affecting the availability of suitable housing units for various segments of the Saudi society. The most critical obstacle is the high cost of land followed by the low income of the families, high cost of construction, high interest rate of mortgages and shortage of suitable residential lands.

The study concludes with a number of proposed recommendations that can contribute to address the current shortage of suitable housing units.

This study aims to explore the effect of Saudi Vision 2030 and its government initiatives on macroeconomic variables related to housing.

This exploratory study used an empirical–analytical approach. Based on secondary data, a set of hypotheses was contrasted to verify whether there has been any change in the trends of macroeconomic variables related to housing after Saudi Vision 2030 entered into force.

The results show that the trend of percentage of housing ownership went from a continuous decrease to accelerated growth since the implementation of Saudi Vision 2030. However, the effect of these advances is not observed in non-oil gross domestic product (GDP) or in the economic activities of the construction, real estate and financial services sectors.

This study notes that despite successful housing outcomes, it appears that Saudi Vision 2030 does not have a positive impact on non-oil GDP. Consequently, government entities should review the degree to which other economic activities contribute to non-oil GDP. A limitation of the study was that the GDP of housing construction and marketing and that of granting mortgage loans were not specifically available, nor were data on public and private investment made for implementing government initiatives.

To the best of the authors’ knowledge, this is the first study to explore the effect of Saudi Vision 2030 on housing and its contribution to the economy.

The importance of housing in enhancing the quality of life has been widely reported. It represents one of the basic human needs, provides protection from harm and ensures survival. Like many developing countries, different Ghanaian governments have variously pursued several programs and interventionsdirected at addressing the country's housing challenges including housing loan schemes in the colonial era to affordable housing projects in the 2000s. Notwithstanding, access to adequate housing for the low to middle-income groups still remains unresolved. This paper is an attempt to gain deeper insights into Ghana's housing situation, its challenges and the efforts made by governments during the periods before independence and after independence. The nature of the housing policies implemented during such eras is explored and the reasons for the implementation failures examined. In the end, the paper provides policy recommendations that could potentially help increase the supply of affordable urban housing in the country. The paper calls for a strong political will and pragmatic intelligence in the implementation of housing policies and programs in the country. Mechanisms to provide sufficienthousing finance for the poor to adequately participate in the housing market have also been outlined. It is concluded that the over-empowerment of the private real estate sector to be the major providers of housing may not be optimal. Rather, it would only lead to the inability of the poor to be able to actively participate in the housing market, consequently exacerbating housing poverty. Effective public-private partnership has the potential to guarantee the supply of reasonably-priced and affordable housing provision.

TiN and TiAlVN films have been prepared by DC magnetron sputtering technique at room temperature. TiN target has been used to deposit TiN thin film under pure argon (100 percent Ar) gas. Additionally, Ti6Al4V alloy target has been used to deposit TiAlVN under nitrogen and argon gas (50 percent Ar and 50 percent N₂). In this paper, two substrate types have been used: stainless steel 304 and Si(100). This analysis has confirmed that the nitride films, (TiN/Si) and TiAlVN in both cases, have been produced. Energy Depressive X-ray Spectroscopy (EDX) measurement confirmed that the TiN/Si was stoichiometry, where the N/Ti ratio was about 1 with low oxygen contamination. The results obtained have indicated that the TiAlVN has more resistance to corrosion than TiN film in 3.5 percent NaCl at 25°C (seawater). Both films, TiAlVN/SS304 and TiN/SS304, have shown improved corrosion resistance compared with virgin 304 substrate. Microhardness was carried out using Vickers method; the microhardness values for TiN/SS304 and TiAlVN/SS304 were approximately 7.5 GPa and 25.3 GPa, respectively. The paper aims to discuss these issues.

The films were prepared by a DC magnetron sputtering system starting from high pure (99.99 percent) Ti6Al4V target (Al 6wt%, V 4wt% and balance Ti) in plasma discharge argon/nitrogen (50 percent Ar and 50 percent N₂) for deposition of TiAlVN film. Pure TiN target (99.99 percent) was used for preparation of TiN film in pure argon plasma. The diameter of target was 50 mm and the power applied for preparation of the two films was 100 W. A cylindrical high-vacuum chamber (Figure 2) made of stainless steel 316, with height 363 mm diameter, was fabricated locally. Scanning electron microscope images have been used to discover the films morphology. The composition of the films has been determined by EDX technique for films deposited on Si substrate. The electrochemical corrosion test was carried out using conventional three-electrode cell of 300 ml capacity by using Voltalab PGZ 301 system (France) using Tafel extrapolation method and electrochemical impedance spectroscopy techniques.

TiN and TiAlVN films have been prepared by DC magnetron sputtering technique without heating of the substrates holder. The effects of the composition of nitride films on mechanical and corrosion properties were investigated. The composition of the films has been determined by EDX technique. The effect of using titanium alloy (Ti with Al and V) on the composition and crystalline quality has been investigated. The microhardness is strongly dependent on the addition of the Al and V elements, and it consequently improves mechanical proprieties. The microhardness values for TiN/SS304 were approximately 7.5 GPa and 25.3 GPa for TiAlVN/SS304. They indicate that prepared films prevent the aggressive action of corrosion media.

TiN and TiAlVN films have been prepared by DC magnetron sputtering method at room temperature. Titanium nitride film, especially TiAlVN, is an effective method to improve the corrosion resistance of SS304. TiAlVN film has exhibited enhanced corrosion resistance and higher microhardness. Independent time-of-flight elastic recoil detection analysis has been used to determine the composition of the film.

To investigate the inhibitive effect of Congo red dye (CR) for aluminium corrosion in strong alkaline solutions and evaluate the synergistic effect of halide ions on the inhibition efficiency.

Corrosion rates of aluminium test coupons were determined by gravimetric technique at 30 and 60°C. Inhibition efficiencies of the additives (0.01‐5.0 mM CR and 5.0 mM CR+0.5 mM halides) were evaluated by comparing corrosion rates of the test coupons in 2 M KOH solution in the absence and presence of the additives.

CR inhibited aluminium corrosion in 2 M KOH by physical adsorption of the dye molecules on the corroding metal surface. Maximum efficiency at 30 and 60°C was 31.72 and 19.32 per cent, respectively. Dye adsorption was enhanced in the presence of halides in the order KCl < KBr < KI, with KI increasing efficiency up to 48.63 and 41.70 per cent at 30 and 60°C, respectively.

Further studies to involve variation of dye and halide concentrations for CR+halide systems to determine the best combination for optimum inhibition synergism.

This paper forms part of an extensive database on the inhibition characteristics of organic dyes for corrosion of different metals in various aggressive environments. This is to serve as a guide to possible applications in metal‐surface anodizing and as additives in surface coatings for service in different environments.

The purpose of this paper is to investigate the effect that different concentrations of the inhibitor sulphathiazole have on the corrosion of aluminum in 0.01, 0.05 and 0.10 M trichloroacetic acid (TCA), and to elucidate the mechanisms of inhibition for this system.

Gravimetric measurements and galvanostatic polarization were used to investigate the effect of sulphathiazole on the corrosion of aluminum in TCA solution. The findings were used to determine the corrosion rates and efficiencies of the inhibitor at different concentrations.

The corrosion rate of aluminum decreased with increasing inhibitor concentrations and the efficiency of inhibition increased with increasing concentration of inhibitor up to almost 89 percent in 0.01 M TCA and up to 65.87 percent in 0.10 M TCA. The concentrations of inhibitor were in the range of 5‐20 mM. Absorption of the inhibitor was onto the aluminum surface and consistent with the Langmuir adsorption isotherm. A plot of log (θ/1−θ) versus log C gave a straight line, which suggests that the inhibitor covers both the anodic and cathodic regions. From the plot of the isotherm, it was observed that one inhibitor molecule occupies more than one active site. The mean ΔG_ads⁰ values were negative almost in all cases, indicating that the adsorption was spontaneous and that the mechanism of adsorption was physical – i.e. electrostatic attraction. Polarization data revealed that the inhibitor functions as a mixed inhibitor.

The paper deals with the inhibition of corrosion of 2S commercially pure aluminum in 0.01, 0.05 and 0.10 M solutions of TCA. To date, not much detailed information has been generated about this problem.

To appraise the inhibiting effect of Ocimum basilicum extract on aluminium corrosion in 2 M HCl and 2 M KOH solutions, respectively, at 30 and 60°C.

Corrosion rates were determined using the gas‐volumetric technique and the values obtained in absence and presence of extract was used in calculation of the inhibition efficiency. The mechanism of inhibition was estimated from the trend of inhibition efficiency with temperature.

Ocimum basilicum extract was found to inhibit aluminium corrosion in the acidic and alkaline environments. Inhibition efficiency increased with extract concentration but decreased with rise in temperature, suggesting physical adsorption of the organic matter on the metal surface. These results were corroborated by kinetic and activation parameters for corrosion and adsorption processes evaluated from the experimental data at the temperatures studied. Halide additives synergistically improved the inhibition efficiency of the extract.

This paper provides new information on the possible application of Ocimum basilicum extract as an environmentally friendly corrosion inhibitor. The mixed extract – iodide formulation provides an effective means for retarding aluminium corrosion even in highly aggressive alkaline environments.

The purpose of this paper is to discuss the housing delivery within the Saudi Vision 2030 through an in-depth reading of the Saudi Vision 2030 from the researcher’s point of view and to identify the most significant aspects that may affect housing delivery in the country.

In this study, the desktop study technique was followed to review the key related literature, collect the data and analyze secondary data. The content analysis technique was used for data analysis of gathered documents and secondary data.

The findings reveal that there are several commitments in the Saudi Vision 2030 from the Saudi Government to be an exemplary leading nation in all aspects, including the delivery of affordable housing. Housing shortage, housing cost, demographic changes and land scarcity are identified as significant reasons for the lack of providing affordable housing.

The opinions of policymakers is very important, but due to time limitation, it has not been addressed. Future research can assess the Saudi Vision 2030 based on the study of the policymakers, professionals and academics to have better insights.

The paper contributes to discussing the housing delivery within the Saudi Vision 2030 and identifying the most significant aspects that may affect the housing delivery from the researcher’s point of view. Only a few studies have discussed the housing issues within the Saudi Vision 2030.

To investigate the efficacy of Congo red dye (CR) as an inhibitor of the acid corrosion of mild steel and aluminium alloy (AA 1060) and to assess the influence of halide ions on the inhibition efficiency.

Corrosion rates were estimated by monitoring the weight losses of the metal specimen as a function of time at different temperatures. Inhibition efficiency was determined by comparing the corrosion rates in the acid medium in the absence and presence of the additive.

CR dye reduced the corrosion rates of mild steel and aluminium in the acidic environment. Better inhibition was observed with the mild steel specimen. Protection efficiency was sensitive to inhibitor concentration as well as temperature and generally increased with an increase in CR dye concentration. The halide additives improved the inhibition efficiency in the order KCl < KBr < KI.

The inhibiting effect of CR dye was studied within a fixed concentration range, which could be expanded for further studies. The same applies to the CR+halide systems. Also, the dye structure could be modified by introducing different functional groups, and the effect on inhibition efficiency investigated.

The research findings could find practical application in corrosion control in aqueous acidic environments.

This paper provides new information on the inhibiting characteristics of CR dye under the specified conditions, as a guide to possible applications in metal surface anodizing and surface coatings.