Elucidation of corrosion inhibition property of compounds isolated from Butanolic Date Palm Leaves extract for low carbon steel in 15% HCl solution: Experimental and theoretical approaches

The present work reports on the corrosion inhibition property of compounds isolated from butanolic extract of Date Palm leaves for low carbon steel in 15% HCl solution. Six compounds were isolated from Date Palm leaves and purified using a combination of column chromatography, thin layer chromatography, and Prep HPLC-MS system. The isolated compounds were characterized using 1H NMR, 13C NMR, and GC–MS. Their identity was revealed to be a mixture of fatty alkanes, oleanolic acid (OA), vanillyl alcohol (VA), b-Sitosterol-3-O-b-D-glucoside (b-SSG), sucrose sugar, and carotenoid lutein. As a result of the amount of the different isolates obtained, only three out of the six compounds namely b-SSG, OA, and VA were tested for anticorrosion property for low carbon steel in 15% HCl. The corrosion inhibition of the isolated compounds was performed using weight loss and electrochemical techniques. Surface morphology analysis of the corroded steel in the absence and presence of the isolated compounds was undertaken using SEM/EDAX and 3D optical profilometer. Also, DFT calculations was performed in order to indicate the reactivities and bonding sites of the isolated molecules as well as Monte Carlos simulations (MCS) to determine the energy of interaction between the inhibitors and carbon steel surface. Results obtained show that the values of inhibition efficiency (IE) for the different isolated compounds at the concentration (35 ppm) studied follow the trend: b-SSG (46.57%) > VAisolated (39.30%) > VAcommercial (36.81%) > OA (31.94%) at 25 �C. It is also noted that, for the isolated OA, IE increased with increase in concentration but decreased with increase in temperature. For isolated VA, IE decreased with increase in temperature. However, for the commercial VA, IE slightly increased with rise in temperature. The experimental results are in agreement with the theoretical prediction. In both predicted and experimental results, b-SSG is the best corrosion inhibitor

Kinetics and thermodynamic studies of adsorption of malachite green onto unmodified and EDTA-modified groundnut husk

A batch experiment was applied to study the adsorption of malachite green from aqueous solution by unmodified and ethylene diamine tetraacetic acid (EDTA)-modified groundnut husk. The effect of initial dye concentration, temperature, contact time and pH on the sorption process was investigated. The Langmuir and Freundlich adsorption isotherms were applied to test the experimental data. The chemically modified groundnut husk agreed well with both the Langmuir and Freundlich models at the temperature below the room temperature (25°C) and above the room temperature. Unmodified groundnut husk showed poor agreement with the isotherm at temperature below the room temperature but fits well into the model at higher temperature. Kinetics of the adsorption with respect to the initial dye concentration and temperature was also investigated. The pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to test the kinetic data. Obtained data were fitted properly in the pseudo-second-order kinetic model. The thermodynamic parameters such as change in free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) were also determined and the results obtained confirmed that the sorption process is feasible, spontaneous, and endothermic

Cement–paperboard composite for speaker/woofer casing: Experimental trend analysis (ETA) and performance evaluation

One of the uses of particle board is in the design of speaker/woofer casing, but with increasing demand, the cost is skyrocketing, effects of which lead to the high cost of end-use woofer gadgets. Cement–paper composite reinforced with snail shell powder/banana fiber was developed as an alternative. The fiber was grouped into two; untreated banana fiber (UBF) and treated banana fiber (TBF) (treated with 1 M NaOH). Fibers were infused into the composite at 0%, 0.5%, 1%, 1.5%, 2%, and 2.5% by weight of paper pulp while snail shell powder was added at 15 wt.% constant proportion for all samples produced. Curing was carried out for 28 and 56 days, respectively. The composite boards produced were examined for physical, mechanical, and microstructural properties. Results obtained indicated an uptrend in water absorption and thickness swelling at increasing fiber loading. Internal bond strength, screw holding strength, moduli of rupture, and elasticity were observed to be enhanced with increment in fiber proportion. It was further noticed that alkaline TBF performed better than the untreated fiber, hence recommended for paperboard production. Experimental trend and performance analysis engaged in revealed hydration to be the most efficient experimental variable and important for overall property maximization in cement–paper composite. Performance evaluation conducted showed effective property index was noticed to be highest for composite board doped with 2.5 wt.% TBF

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Mortality of emergency abdominal surgery in high-, middle- and low-income countries

Background: Surgical mortality data are collected routinely in high-income countries, yet virtually no low- or middle-income countries have outcome surveillance in place. The aim was prospectively to collect worldwide mortality data following emergency abdominal surgery, comparing findings across countries with a low, middle or high Human Development Index (HDI). Methods: This was a prospective, multicentre, cohort study. Self-selected hospitals performing emergency surgery submitted prespecified data for consecutive patients from at least one 2-week interval during July to December 2014. Postoperative mortality was analysed by hierarchical multivariable logistic regression. Results: Data were obtained for 10 745 patients from 357 centres in 58 countries; 6538 were from high-, 2889 from middle- and 1318 from low-HDI settings. The overall mortality rate was 1⋅6 per cent at 24 h (high 1⋅1 per cent, middle 1⋅9 per cent, low 3⋅4 per cent; P < 0⋅001), increasing to 5⋅4 per cent by 30 days (high 4⋅5 per cent, middle 6⋅0 per cent, low 8⋅6 per cent; P < 0⋅001). Of the 578 patients who died, 404 (69⋅9 per cent) did so between 24 h and 30 days following surgery (high 74⋅2 per cent, middle 68⋅8 per cent, low 60⋅5 per cent). After adjustment, 30-day mortality remained higher in middle-income (odds ratio (OR) 2⋅78, 95 per cent c.i. 1⋅84 to 4⋅20) and low-income (OR 2⋅97, 1⋅84 to 4⋅81) countries. Surgical safety checklist use was less frequent in low- and middle-income countries, but when used was associated with reduced mortality at 30 days. Conclusion: Mortality is three times higher in low- compared with high-HDI countries even when adjusted for prognostic factors. Patient safety factors may have an important role. Registration number: NCT02179112 (http://www.clinicaltrials.gov)

Associate, Hyperdomainlike, and Presimplifiable Hyperrings

Based on the works of Axtell et al., Anderson et al., and Ghanem on associate, domainlike, and presimplifiable rings, we introduce new hyperrings called associate, hyperdomainlike, and presimplifiable hyperrings. Some elementary properties of these new hyperrings and their relationships are presented

Influence of Organic Acids and Related Organic Compounds on Corrosion Behavior of Stainless Steel—A Critical Review

Stainless steel is one of the most commonly used structural materials in industry for the transportation of liquids such as water, acids, and organic compounds. Corrosion is a major concern in industry due to the use of strong mineral acids, feedstock contamination, flow, aqueous environments, and high temperatures. Stainless steel is the most commonly used material in the petrochemical industry because of its characteristics of self-protectiveness, offered by thin passive oxides, and its metallurgical composition. However, chlorides and mineral acids attack the stainless steel continuously, consequently breaking down the passivation film, causing a continuous challenge from corrosion. The corrosion in stainless steel is influenced by many factors including flow rate, temperature, pressure, ethanol concentration, and chloride ion content. This review describes the impact of organic compounds and organic acids on the degradation behavior of stainless steel. The review also summarizes the commonly used organic compounds and their applications. It has been demonstrated that organic acid concentration, temperature, and halide impurities have significant effects on susceptibility to pitting corrosion by damaging the passivation film. The phenomenon of corrosion in stainless steel is quite different in immersion tests and electrochemical potentiodynamic polarization. This review article discusses the importance of organic compounds and their corrosion behavior on steel. The article also puts emphasis on the roles of corrosion inhibitors, monitoring methods, corrosion management, and forms of corrosion

In Vitro Corrosion and Bioactivity Performance of Surface-Treated Ti-20Nb-13Zr Alloys for Orthopedic Applications

The influence of surface treatments on the microstructure, in vitro bioactivity and corrosion protection performance of newly fabricated Ti-20Nb-13Zr (TNZ) alloys was evaluated in simulated body fluid (SBF). The TNZ alloy specimens were treated with separate aqueous solutions of NaOH and H2O2 and with a mixture of both, followed by thermal treatment. The nanoporous network surface structure observed in H2O2-treated and alkali-treated specimens was entirely different from the rod-like morphology observed in alkali hydrogen peroxide-treated specimens. XRD results revealed the formation of TiO2 and sodium titanate layers on the TNZ specimens during surface treatments. The water contact angle results implied that the surface-treated specimens exhibited improved surface hydrophilicity, which probably improved the bioactivity of the TNZ specimens. The in vitro corrosion protection performance of the surface-treated TNZ specimens was analyzed using electrochemical corrosion testing in SBF, and the obtained results indicated that the surface-treated specimens exhibited improved corrosion resistance performance compared to that of the bare TNZ specimen. The in vitro bioactivity of the treated TNZ specimens was assessed by soaking in SBF, and all the investigated treated specimens showed numerous apatite nucleation spheres within 3 days of immersion in SBF

Impact of the decision to use healthcare facilities among farming households on labour productivity in Ogun State, Nigeria

Productivity of agricultural labour is central to the improvement of livelihoods of rural population. This study used an instrumental variable approach to examine the impact of healthcare facilities use on household labour productivity using distance to healthcare facilities as an instrument. A multistage sampling procedure was used in selecting 200 households comprising 96 users and 104 non-users of healthcare facilities. The result revealed that the agricultural productivity of users of healthcare facilities was ₦652.34 (USD 1.65) per man-day higher than non-users. The result further showed that age (p < 0.1), sex (p < 0.05), contact with health extension worker (p < 0.01), incapacitation due to illness (p < 0.05) and distance to healthcare facilities (p < 0.01) significantly influenced the decision to use healthcare facilities while membership of cooperative society (p < 0.05), area cultivated and use of health care facilities (p < 0.1) significantly influenced labour productivity. The study concluded that increased distance to healthcare facilities reduces its utilisation while being member of cooperative society and utilisation of healthcare facilities increases labour productivity. This study recommended that health extension workers need to intensify their efforts in educating the households on the need to use healthcare facilities when they are sick; this is expected to improve the healthy time of the households which will invariably increase their productivity

Effect of Solutionizing Duration and Temperature on the Electrochemical Corrosion and Pitting Resistance of Cold-Rolled Super Austenitic Stainless Steel

The solution annealing of cold rolled super austenitic stainless steel UN08029 alloy was carried out to investigate the role of solutionizing duration and temperature on the electrochemical corrosion and pitting resistance of the alloy. Linear polarization, cyclic potentiodynamic, and electrochemical impedance spectroscopy techniques were used to evaluate the electrochemical behavior in 3.5% NaCl solution. The microstructural analysis of the solutionized samples revealed the formation of uniform equiaxed grains from elongated columnar grains, which size increases with duration and temperature. The charge transfer resistance shows an increasing corrosion protectiveness of 46 to 60% with increasing solutionizing duration from 30 to 120 min. Similarly, a 45, 52, 60, and 26% improvement in the corrosion performance was obtained for sample solutionized at 1000, 1100, 1200, and 1300 °C, respectively. In general, the solutionized samples demonstrated improved resistance over the as-received alloy, and this behavior increases with solutionizing duration and temperature. Though the pitting potential drops below that of the as-received alloy, the hysteresis loop revealed that the solutionized samples are less prone to pitting damage, and the sample solutionized at 1200 °C for 120 min exhibited optimum pitting corrosion resistance. The microstructural influence on corrosion was also discussed