The genus Buddleia, included in the family Loganiaceae, and previously classified in a family of its own, the Buddlejaceae, is now classified in the family Scrophulariaceae. Native to Asis, Africa, North and South America, Buddleia is a genus containing 100 species, 50 being distributed in America, of which 16 grow in Mexico . Buddleia species are widespread and share some remarkable similarities in their medicinal uses. This may well indicate the presence of the same or similar compounds with a particular pharmacological action. A patterns is emerging about the composition of these compounds; flavonoid and iridoid glycosids being the major seccondary metabolites that have been isolated to date . Buddleiaperfoliata became officialy recognized in the 1930 Mexican Pharmacopoeia where it was shown to have antisudorific activity . This plant also contains essential oil, tannic, gallic and oxalic acids . In folk medicines, it is used in the treatment for tuberculosis as well as for catarrh, ptyalism and headaches . In the present paper, we evaluated the inhibitory effect ofBuddleiaperfoliata in the corrosionof 1018 carbonsteel in 0.5M H 2 SO 4 by using both gravimetric and electrochemical techniques.
was mild steel. All potentials given in this study were referred to this reference electrode. The working electrode was immersed in the test solution for 30 min to a establish steady state open circuit potential (Eocp). After measuring the E ocp , the electrochemical measurements were performed. All electrochemical tests have been performed in aerated solutions at 298 ± 2 K. The EIS experiments were conducted in the frequency range with high limit of 100 kHz and different low limit 0.1 Hz at open circuit potential, with 10 points per decade, at the rest potential, after 30 min of acid immersion, by applying 10 mV ac voltage peak-to-peak. Nyquist plots were made from these experiments. In order to extract the electrochemical parameters, the Z-view software was used.
About 2kg of Jatropha was obtained from Omu-Aran town, the Jatropha stem was sun dried and then grinded with an industrial grinder into a powdered form, it was then filtered. The fine powder obtained was completely soaked in ethanol solution for 24hrs with intermittent stirring to have a homogeneous solution and the extract collected through filtering in the form of a paste-like sample. The filtrate was then subjected to evaporation process to remove the excess of alcohol in it. The filtrate obtained was the inhibitor in pure form, so the pure extract was later collected and stored. The stock solution of the extract was prepared by using different weights of the extract that dissolved in 10 liters of seawater. The chemical compositions of the Jatropha stem were determined. Acetone was then used to dry and preserve the extract in a desiccator to prevent it from reacting with the environment.
Corrosion represents high losses to the economy, therefore, researches on the minimization of its damages in materials, mainly the metallic ones, are necessary. Among the various alternatives of protection against corrosion, there is the application ofcorrosion inhibitors that can minimize or even stop the corrosive process of metallic materials. However, at present, substances usually used as corrosion inhibitors present high toxicity, being considered harmful components to the environment and to human health. Therefore, there is an urgent need for studies on viable corrosion inhibitors, by considering not only economic but also environmental costs. The present work studied the use of cocoa bark extract (Theobrama cacao L), for possible replacement of benzotriazole (BTAH) in the corrosioninhibitionof ASTM 1020 carbonsteel (CS- ASTM 1020) in 18.23 g.L -1 hydrochloric acid
The inhibition efficiency(IE)ofcarbonsteel immersed in aqueous medium for one day in the absence and presence of inhibitor at various concentration has been measured by weight loss study[12-14]. The corrosioninhibition efficiency of phthalic acid alone is given in the Table 1. It is found that the inhibition efficiency is decreases the concentration of phthalic acid increases. For example 50 ppm of phthalic acid shows 61% of IE, but 150ppm of phthalic acid accelerate the corrosion. The inhibition efficiency of Zn 2+ alone in the system shows some IE (Table 2).
This is an indication that the mass loss is sensitive to the concentration of the lignin extract. This trend is most likely due to the fact that adsorption and surface coverage of the steel increases with concentration of the inhibitor . Thus the surface of the steel is more effectively separated from the medium . The inhibitive effect of the lignin extract is attributed to the presence of some functional groups in the extract as revealed by the Infrared Spectrophotometer result (Figure 4).
hours of immersion. The C-steelcorrosion rate (Wcorr) was greatly reduced upon the addition of the inhibitors for all immersion times, reaching 0.736 mm/y and 0.925 mm/y in the presence of the extract and its fraction after 48 h of immersion, respectively. Even these corrosion rates are relatively high, the inhibitory action of these extracts is undoubted. According to Gentil, for cheap materials, like carbonsteel, the corrosion rate could be acceptable in the range of 0.225 to 1.5 mm/y 22 . The inhibition eiciency for
The corrosioninhibition efficiency (IE) of an aqueous extract Tridax Procumbens(TP) in controlling the corrosionofcarbonsteel aqueous medium containing 60 ppm of chloride ions in absence and presence of Zn 2+ has been studied by weight loss method. The formulation consisting of 1 ml of Tridax Procumbens extract and 150 ppm of Zn 2+ offers 96% inhibition efficiency. The synergistic effect exists between Tridax Procumbens and Zn 2+ system. Polarization study shows that the Tridax Procumbens – Zn 2+ system function as a cathodic inhibitor. AC impedance spectra reveal that a protective film formed on the surface. The Adsorption equilibrium exhibited better fit to Langmuir isotherm than Freundlich isotherm. FTIR spectra reveal that the protective film consists of Fe 2+ -Tridax Procumbens and Zn(OH) 2 .
the blank (maximum shifts of 25 and 16 mV, respectively), which demonstrates that this extract acts as a mixed-type inhibitor with predominantly anodic characteristics. The cathodic Tafel slopes (bc) did not change signiicantly with the addition of the extracts (Table 1), which indicates that the adsorbed inhibitor molecules did not affect the hydrogen evolution reaction, i.e., the hydrogen evolution was diminished exclusively by the surface blocking effect. Regarding the anodic region, the anodic Tafel slopes (ba) also did not change signiicantly with the addition of the inhibitor, which reveals that the inhibitor, which adsorbed to the carbonsteel, did not affect the metal dissolution reaction. The inhibition eficiency calculated from the j corr
Plant extract contains organic compounds having polar atoms or groups which are adsorbed on the metal surface. Obot and Obi-Egbedi  reported that compounds interact by mutual repulsion or attraction when Ipomoea Involcrata plant extract was used as an inhibitor. This may be advocated as the reason for the slight departure of the slope values from unity as explained by Obot and Obi-Egbedi . Although, in this study, the slope is fixed at 1 prior to linear fitting but few points were still slightly deviated from the straight line, which may be due to mutual repulsion or attraction of the polar atoms or groups as observed by Obot and Obi-Egbedi .
The rate-determining step for the hydrogen evolution reaction is the recombination of adsorbed hydrogen atoms to form hydrogen molecules Eq. 8. At low concentration (1M) the transition state of the rate determining recombination step represent less orderly arrangement relative to initial state and hence a positive value for the entropy of activation was obtained. As acid concentration increased (3 M), the values of ∆S * decreased, but it still positive. This may be due to the activated complex have some order than the initial state. Further increase in acid concentration (5 M), the entropy of activation has a negative value. These indicate that the activated complex is more orderly relative to the initial state.
Abstract: Problem statement: Damage due to corrosion is a significant problem worldwide. Countries around the world have estimated that the cost ofcorrosion to their national economies to be 3-4% of their gross national product. Approach: Design and implementation a new steel piling of the Corrosion Management Program (CMP) in Al-Zubare harbor. Corrosion management algorithm can be divided into three major phases. Phase 1 of the program is the programmatic assessment of the project. Phase 2 of the program involves physical assessment and actual remediation. Phase 3 of the program mainly deals with future monitoring of the repaired structure. Results: The CMP included activities performed to mitigate corrosion, to repair corrosion-induced damage and to replace the structures that are badly corroded. Installation and maintenance requirements are identified. Conclusion: The data was collected from the tide table for Al-Zubare Harbor in the year 2004. The highest tide of the year would fall on 17 October 2004 at 1.05 am with level 3.5 m, while the lowest tide of the year would fall on 3 July 2004 at 5.13 am with level 0m. The detection results show that this program is feasible and effective.
Linalool, the mild steel surface roughness was significantly reduced indicating the inhibiting action of both additives. The reduction in the surface roughness of mild steel coupons in the presence of CA compared to the Linalool confirms that leaf extractof CA is a better corrosion inhibitor than that of its chemical constituent, Linalool. The surface morphology results are in agreement with the results obtained from electrochemical impedance spectroscopy and polarization curves measurements and points to the existence of good inhibiting action of CA leaf extract and Linalool.
Laboratory experiment was aimed to determine the appropriate hydraulic ratio between the important cross-sections of the modification device, and next to influence of the modifier amount and the pressure altitude on values of residual magnesium, as necessary conditions for the formation of spheroidal graphite. There are a large number of possible influences during modification process and to eliminate them these variables were determined for the measurement - change of amount of modifier, the change of pressure altitude modification. The variables set as unchanging were - cross-sectional areas of flow of modification device, chemical composition of the initial cast iron, the method of melting, overheating temperature of the initial cast iron, modifier - type, granulation, the amount of inoculants.
pharmacological activities are potentially of interest to clinical use for Alzheimer’s disease . Eighteen medicinal plants of Brazil were screened for inhibitory activity on AChE, the results show that various plants are very interesting for further isolation of acetylcholinesterase inhibitors, which are widely used in the treatment of Alzheimer’s disease, galanthamine, an alkaloid from plants of the Amaryllidaceae family, is a selective reversible long-acting and competitive acetylcholinesterase inhibitor (AChEI). The extract is considered to be more effective in the treatment of Alzheimer’s disease (AD) and to have fewer limitations than physostigmine and tacrine are relevant in terms of searching for novel formulations or compounds for AD treatment . This is the result of the first tests, yellow backgrounds with white spots for inhibiting extract was visible after about 5 minutes and so L. styraciflua aerial parts methanol extract apparently tested positive enzyme inhibition in concentration of 10 mg/mL. The activity of the methanol extractof L. styraciflua may be explained by the presence of carbohydrates, triterpenes, flavonoids and tannins and also for the isolated bioactive compounds where some of the isolated compounds (kaempferol sugars) showed a significant acetylcholinesterase inhibiton . Also many plants as Sophora flavescens showed a significant acetylcholinesterase inhibition and this activity is due to prenylated flavonoid, 8- lavandulylkaempferol which exhibited significant inhibitory effects with IC 50 values of 7.10 and 8.11μM for
and 58% for N = 2 and N = 3, respectively). This is because bidders are very heterogeneous and the seller should set a high screening level to avoid low bidders from participating. This somehow carries over for median and higher quality and size auctions when the seller’s private value is the appraisal value. Policy recommendations with such a low probability of selling may not make sense in practice, especially for goods with a potential high storage cost. This effect seems to be less expressive when the seller faces no outside option. As can be seen, the practical implementation of the auction theory can be sometimes difficult in the sense that usual choices for the seller’s private value may lead to recommendation of mechanisms with very low probability of trading. This may question the relevance of considering expected payoff in the maximization process.
As we know that to find the area of sector the angle made by the chord (that is chord which divides the circle) is required. But in the below method we find the ratio of the segments of the circle. Thus by relating the area of segment to the area of sector the area of sector could be found. The ratio of area of segments is related to tangents that are drawn through diameter on either side.
was based on plastic contrast. For example, to emphasize the central part among the other composition, the architect 'in the middle third of the main wall had arranged an extensive (5.60 m) but shallow (75 cm) niche‖ [16, 46p]. The building itself was small in scale, and to emphasize its monumentality and visually to expand its interior, the sculptors correlated the height of zofor (1.40 m) to 6-meter span of the building. Frieze made with account of the angle of perspective, was decorated with garlands, supported by frames of children. The images of the frieze were original in the "very understanding of the ideal of human beauty and its artistic expression in plastic forms" [44, 61p]. Often in these images there was observed a deliberate asymmetry (in the faces), the disproportion (in the figures), aimed to correct the visual angle. For the sculpture in Toprak-kala "a rhythmic repetition of similar sculptural groups, determining architectonic division of interior, was characteristic" . The style and the manner of sculpture, for example, of friezes were the same as of acanthus, volutes. So, it can be assumed that the ancient sculptors have been actively involved not only in the development of sculptures, but in architectural and decorative compositions (especially of capitals), and the connection between the latters was very tight. In general, the nature of decoration of the premises depended on the functions of the latter: "household and service rooms were modestly furnished, as for residential and ceremonial rooms they were finished with the appropriate splendor‖ [46, 67p]. The sculpture, obeying the architecture, served as an element of its design. In Bactria a monumental sculpture "was designed primarily to be installed in the temples" [22, 901p]. In architectural
A methodology for quantifying the contamination after abrasive blasting by Aluminum Oxide and Martensitic CarbonSteel particles in Super Duplex and CarbonSteel substrates has been developed. The method consisted of performing x-ray diffraction in the blasted steel substrates and calculating the particle contamination using Rietveld Quantitative Method. In this way, it is possible to evaluate the substrate volume in which the abrasive particles have been trapped (taking into account the surface roughness) rather than solely performing visual examination, as indicated by standards documents. Equations describing the intensity model of the diffracted peaks as well as those describing the quantitative measurements are presented. Correction functions are also employed to compensate the effect of the surface roughness generated on the metallic substrates after blasting. Alumina and martensitic steel abrasives contaminations were detected and quantiied in both steel substrates. Results showed that Super Duplex Steel substrates revealed a higher degree of contamination when compared to the CarbonSteel substrates, both for alumina abrasives as for martensitic abrasives. Also, the abrasive that generated the lower degree of contamination was the Martensitic CarbonSteel, for both substrates.