A theoretical study of some hydroxamic acids as corrosion inhibitors for carbon steel

The corrosion inhibition characteristics of two hydroxamic acids, i.e., oxalyl-dihydroxamic acid (C2) and pimeloyl-1,5-di-hydroxamic acid (C7), on carbon steel has been studied using density functional theory (DFT). Quantum chemical parameters such as highest occupied molecular orbital energy (E_HOMO), lowest unoccupied molecular orbital energy (E_LUMO), and energy gap (ΔE) have been calculated using B3LYP/6-31 + G∗∗ basis set. The relationship between the inhibition efficiency and quantum chemical parameters has been discussed in order to elucidate the inhibition mechanism of these compounds.     

Single daily dose of digoxin for maintenance therapy of infants and children with cardiac disease: is it reliable?

Between July 1990 and September 1991, 30 infants and children, most of whom had a congenital heart defect and who had been treated at least during the previous 20 days by two daily doses of digoxin and were in a stable clinical condition, were selected at random. A maintenance dose of digoxin was administered at 24-h intervals for 7 days in the study group (n = 15); no change was made in the 12-h dosage interval in the control group (n = 15). When the serum digoxin concentrations were compared, no significant difference was found between pre- and poststudy values in the study group (1.0 +/- 0.6 and 0.8 +/- 0.3 ng/ml, respectively) or between the control and study groups (0.9 +/- 0.6 and 0.8 +/- 0.3 ng/ml, respectively) in terms of trough serum digoxin concentrations. Although the peak serum concentrations in the study group were increased significantly (2.3 +/- 0.8 ng/ml) compared with prestudy peak levels (1.6 +/- 0.7 ng/ml, p < 0.05) and with the level in the control group (1.5 +/- 0.8 ng/ml, p < 0.05), a toxic concentration was not reached, and toxicity symptoms were not observed clinically. Blood pressure, heart rate, and liver size did not change significantly in any patient during the study.     

Three-dimensional nickel nanodomes: Efficient electrocatalysts for water splitting

Highly efficient and stable three-dimensional (3D) Ni nanodome (Ni-NDs) arrays were fabricated as candidate cathode materials for alkaline water splitting. The NDs were prepared by a combined methods of soft lithography-nanosphere lithography, physical vapor deposition (PVD) and electrochemical deposition using polydimethylsiloxane (PDMS) as template. The water splitting activity of the 3D nanostructures were examined in 6 M KOH solution using polarization and electrochemical impedance spectroscopy techniques. The data obtained showed that well-structured and uniformly distributed Ni-NDs could be fabricated using this combined method. The ND arrays perform excellent hydrogen evolution activity with respect to Ni plate as a reference point since their nano-sized roughness results in larger real surface area. By comparing with Ni plate, lower hydrogen onset potential (85 mV) and charge transfer resistance (90.1%) as well as higher current density (90.4%) corresponding to the amount of evolved hydrogen were observed at the NDs. The Ni-NDs have high time-stability in the electrolysis conditions. It is believed that the Ni-ND arrays contribute to the design of novel electrocatalytic electrodes as candidate supporting materials.     

A review of the current applications of genetic algorithms in assembly line balancing

Most of the problems involving the design and plan of manufacturing systems are combinatorial and NP-hard. A well-known manufacturing optimization problem is the assembly line balancing problem (ALBP). Due to the complexity of the problem, in recent years, a growing number of researchers have employed genetic algorithms. In this article, a survey has been conducted from the recent published literature on assembly line balancing including genetic algorithms. In particular, we have summarized the main specifications of the problems studied, the genetic algorithms suggested and the objective functions used in evaluating the performance of the genetic algorithms. Moreover, future research directions have been identified and are suggested.     

Ultrasound-assisted adsorption of textile dyes using modified nanoclay: Central composite design optimization

The removal of two anionic dyes, C.I. Acid Orange 7 (AO7) and C.I. Acid Red 17 (AR17), by ultrasound-assisted adsorption on the modified nanoclay in aqueous solutions was studied. The modified nanoclay was characterized by SEM/EDX, BET, XRD and FT-IR techniques. The average crystal size for the interlayer spacing of the modified nanoclay was about 14.3 nm. Central composite design (CCD) was used for the optimization of the operational parameters, including the initial dye concentration, sonication time, adsorbent dosage and temperature. The results demonstrated a good agreement between the predicted values obtained by the model and the experimental values for both AO7 (R²= 0.959) and AR17 (R²=0.971).     

Optimization of primary freeze drying conditions for powdered chicken meat hydrolysate from mechanically deboned chicken residues

Abstract

In this study, mechanically deboned chicken meat residues were hydrolyzed by protease enzyme and chicken meat hydrolyzate was freeze-dried in order to produce high-quality meat powder. Due to its high cost, energy and time consumption, freeze-drying conditions needed to be optimized. Response surface methodology was used for optimization with the independent variables shelf temperature, lyophilization temperature and freezing rate. The responses were sublimation time, solubility and in vitro protein digestibility. The optimum conditions were shelf temperature, 15?°C; lyophilization temperature, –10?°C; and freezing rate, 2.0?°C/min. Sublimation time, solubility and in vitro protein digestibility for this optimum conditions were found to be 590.344?min, 25.626% and 23.808%, respectively.     

Desulfurization of a Turkish lignite at various gas atmospheres by pyrolysis. Effect of mineral matter

An investigation was made of the removal of pyritic and organic sulfur by pyrolysis at ambient pressure of a Turkish lignite under nitrogen and carbon dioxide atmospheres and the effect of mineral matter on the sulfur removal in pyrolysis of HCl and HCl/HF-treated coal under carbon dioxide atmosphere. Results obtained indicated that both pyritic and organic sulfur removal increased with increasing pyrolysis temperature. The pyrolysis in carbon dioxide atmosphere had more effect on the organic sulfur removal at high temperatures. As a consequence of treatment of coal with HCl, pyritic sulfur removal increased but organic sulfur removal decreased. This implies that the removal of carbonates from coal negatively affects the organic sulfur removal. The observed decrease in organic sulfur removal may be related to the decrease in pyrolytic conversion. It was observed that HCl/HF treatment has an increased effect on the pyritic removal and organic sulfur removal during pyrolysis. The increase in organic sulfur removal after HF-treatment therefore might be due to the removal of clay minerals in the raw coal structure. In addition, it may be said that the presence of silicate minerals in the coal matrix can be induced that the easily removable organic sulfur compounds are converted to thermally stable and non-removable organic sulfur compounds (thiophenic or condensed thiophenic compounds) at these temperatures. Increase in the pyritic sulfur removal of HCl-treated and HCl/HF-treated coal samples may be attributed to the fact that increase of mass and/or heat transport in comparison with untreated coal as a result of elimination of mineral matter.     

Synthesis and interfacial properties of aminosilane derivative of acrylated epoxidized soybean oil

In this study silanized acrylated epoxidized soybean oil (silanized‐AESO), a multifunctional monomer, was synthesized by reacting acrylated epoxidized soybean oil with 3‐Aminopropyltriethoxysilane via a Michael addition reaction using less than equivalent amount of the silane. The characterization of silanized‐AESO was done by NMR and IR spectroscopy. Free radically initiated homopolymer of silanized‐AESO was synthesized by using the residual acrylate groups. The silanized‐AESO homopolymer was characterized by IR spectroscopy. The interfacial adhesion of the polymer on glass surface before and after moisture cure was measured according to ASTM D 4541 Pull‐Off Adhesion Test. After moisture curing process, an approximate of eightfold improvement was observed in the adhesion strength. Prolonged exposure to 92% humidity for 48 h caused to approximately 15% decrease in the adhesion strength. Silanized‐AESO was copolymerized with styrene in 1 : 1 weight ratio via radical polymerization. The effect of increased crosslink density upon moisture cure on the mechanical and physical properties of silanized‐AESO‐styrene copolymer was analyzed by DMA (Dynamic Mechanical Analysis), swelling, and surface hardness tests. Upon moisture cure 35% improvement was observed in the storage modulus because of the increase in the crosslink density. According to tan δ curves and surface hardness tests, silanized‐AESO‐styrene copolymer shows heterogeneous morphology in crosslinked areas. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2244–2253, 2007     

Chemical Characteristics of Kavurma with Selected Condiments

A traditional meat product, kavurma, was prepared with the addition of various condiments (sage, thyme, ginger). The effects of condiments and storage time on thiobarbutiric acid (TBA) value, color attributes, pH, moisture, protein and fat contents of kavurma samples were investigated. Also, the effect of condiments on the sensory properties of samples was determined. The TBA values of condiments added samples were significantly lower than that of control. Ginger had a highest antioxidative activity and sensory scores compared to others samples. Color attributes generally decreased during storage and the additives differently affected the color of sample. The moisture content of samples was significantly affected from the condiments and storage period. Although sensory scores of the sample with condiments were higher than control, the difference was not statistically significant. It could be concluded that natural condiments could be used in kavurma production to improve quality characteristics of the product.