Self-assembled monolayer of 2-(octadecylthio)benzothiazole for corrosion protection of copper

Self-assembled monolayer (SAM) of 2-(octadecylthio)benzothiazole (2-OTBT) was formed on a fresh copper surface obtained by nitric acid etching. Optimum conditions for formation of SAM have been established. XPS, AFM and FTIR studies have been used to characterize the SAM. Corrosion protection ability of the SAM has been evaluated in aqueous NaCl solution using electrochemical impedance, EQCN, potentiodynamic polarization and weight-loss studies. 2-OTBT SAM is found to have excellent corrosion protection efficiency in the aq. NaCl solution. The mechanism of corrosion inhibition of copper by 2-OTBT SAM is discussed.     

Short-term toxicity studies of Ficus thonningii Blume (Moraceae) leaf extract in rats

The short‐term toxicity of Ficus thonningii Blume (FT) was studied in Wistar rats following daily oral administration of the leaf extract (250–500 mg kg^?1) for 15 days. Acute toxicity, body weight changes, organ weight, food intake, clinical signs, haematology, gross and tissue histology were monitored. The body weights of treated rats increased progressively, but the changes were not significantly different from control. The relative weights of the essential organs of treated rats were unaffected in both male and female rats. Of the sixteen haematological parameters studied, only the total leukocyte counts and plateletcrit values in male rats fed 500 mg kg^?1 of FT were significantly greater than similar parameters in controls. Histological findings indicated possible testicular, lung and hepatic toxicities. The LD₅₀ of FT was estimated to be >3000 mg kg^?1. The results suggest that short‐term oral application of F. thonningii may not exert severe toxic effects in rats at doses lower than 500 mg kg^?1.     

Thermodynamic properties of simple anharmonic crystals

The equation of state earlier suggested for simple molecular crystals in the high-temperature region is applied to the calculation of thermodynamic functions of solid argon, krypton, xenon, and radon.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 6, pp. 1018–1023, December, 1980.     

Forced cycling of the catalytic oxidation of CO over a V2O5 catalyst—I: concentration cycling

A study was performed on the behaviour of a catalytic reactor in which CO was oxidized over V₂O₅ under transient conditions using square-wave cycling of the reactant ratio. A maximum in the time-average reaction rate was observed at a period of about 20 min, resembling a resonance phenomenon. A minimum in the time-average reaction rate occurred in the range of periods between 40 and 60 min.     

Investigation on the use of macro- and micro-nutrients to improve maize yield in South Western Nigeria

Investigation into the use of macro- and micro-nutrients to increase maize yield was conducted in both the glasshouse and in the field. The glasshouse studies involved ten soil series commonly cultivated to maize in South Western Nigeria, while the field studies were conducted on one soil at Ibadan.Dry matter yield increased above the control with a single application of N, P, K, Ca, Mg, Fe, Cu, Zn and Mn, suggesting that most of the soils in the South Western Nigeria require additions of each of these elements for increased maize production. The size of the response to each element varied from series to series. Soils which were high in organic matter (over 3%) required the lowest N dressings for optimum dry matter yield of maize.In the field studies, a fertilizer combination which included N, P, K, Mg and the micro nutrients Fe, Cu and Zn gave a higher relative yield than the single application of N, P, K, and a combination of NP, NK, Pk or NPK.In the South West Zone of Nigeria, there is no soil testing programme and fertilizers applied by farmers and researchers have not increased yields as expected. Average maize yield on farmers' field is less than 1000 kgha^–1 while on research stations it is 2500 kgha^–1. When compared with 7000 kgha^–1 in U.S.A., these yields are still very low.Different recommendations for the major plant nutrients have been made by many workers in the South West zone based on fertilizer trials [1, 5, 8, 13, 16].None of the recommendations have included the micronutrients and secondary nutrients and the objective of this project was to supply relevant information on this important aspect.     

Electrospun polylactide‐based materials for curcumin release: Photostability,antimicrobial activity,and anticoagulant effect

New microfibrous materials from polylactide and polyvinylpyrrolidone or polyethylene glycol loaded with the natural polyphenolic compound curcumin have been prepared by one‐pot electrospinning. The incorporation of curcumin in the fibers contributes to shielding curcumin from photodestruction and to enhancement of the mechanical properties of the fibers. Moreover, the formation of hydrogen bonds between curcumin and polyvinylpyrrolidone or polyethylene glycol facilitates the drug release. Curcumin release provides for the antibacterial and anticoagulant activity of the curcumin‐loaded mats and prevents adhesion and aggregation of platelets onto the surface of the mats. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42940.     

Diffusion of helium in non-stoichiometric uranium dioxide

Diffusion coefficients of helium in solid UO_2+x at high temperature and various stoichiometric compositions are evaluated by using molecular dynamics simulations based on a partly-ionic model in conjunction with a polaron ‘Free Hopping Approximation’ proposed earlier. The results are compared with existing experimental and simulation data. A strong dependence of the apparent diffusion activation energy on stoichiometry is found and the mechanisms of He migration in non-stoichiometric solid UO_2+x are discussed.     

Control Chart Limits for Monitoring Process Mean Based on Downton's Estimator

Control charts are important tools in statistical process control used to monitor shift in process mean and variance. This paper proposes a control chart for monitoring the process mean using the Downton estimator and provides table of constant factors for computing the control limits for sample size (n ≤ 10). The derived control limits for process mean were compared with control limits based on range statistic. The performance of the proposed control charts was evaluated using the average run length for normal and non‐normal process situations. The obtained results showed that the control chart, using the Downton statistic, performed better than Shewhart chart using range statistic for detection of small shift in the process mean when the process is non‐normal and compares favourably well with Shewhart chart that is normally distributed. Copyright © 2015 John Wiley & Sons, Ltd.     

Investigation of the influence of network‐induced time delays on the activated sludge process behavior in the networked wastewater distributed systems

This paper examines the effects of networked induced time delays on the dissolved oxygen (DO) concentration in the activated sludge process (ASP) of a networked wastewater treatment plant (WWTP). This is a situation in which the controller and the wastewater plant are separated by wide geographical distance. This is a new type of WWTP control that allows two or more WWTPs to be controlled by a single controller placed in a remote location. The objective is to achieve flexibility of control and to reduce its cost. The communication medium between the controller and the WWTPs introduces communication drawbacks into the control system. The influences of network‐induced time delays [controller to actuator delay (τ_ca) and the sensor to controller delay (τ_sc)] over the behavior of the DO process controlled by both nonlinear linearizing and proportional‐integral controllers are investigated for constant and random delays. Investigation of the DO process under random delays was also performed with varying linear controller parameters [proportional gain (K_p) and integral time (T_I)]. Simulation results reveal that large network‐induced time delays in the closed‐loop DO process leads to depletion of the amount of oxygen available for microorganism metabolism, leading to inefficiency of the ASP. The critical delay during which the DO process becomes unstable due to communication drawbacks was also determined for constant and random delays. These values are found to vary depending on the delay type (constant/random), delay magnitude, and the linear controller parameters K_p and T_I. The results of this study would provide useful information for process performance and form the basis for the design of a robust networked control for the DO process capable of mitigating communication drawbacks in a networked wastewater distributed systems. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Preparation and gas transport properties of dual‐layer polysulfone membranes for high pressure CO2 removal from natural gas

Permeability, sorption, and plasticization behaviors of dual‐layer composite membrane were studied. Polysulfone containing 10.7 wt % glycerol as additive was used for preparing a microporous membrane support. A thin top selective layer was prepared using diethylene glycol dimethyl ether as casting solvent. The overall performance of the membrane was evaluated using Scanning Electron Microscopy, and permeation and sorption tests at pressure up to 50 bar. The prepared membrane displayed high permeability at low pressure which gradually decreased with increase in pressure. Permeability of CO₂ was determined to be 84.97 Barrer at 2 bar. Membrane did not show any plasticization tendency up to the experimental pressure of 40 bar. Plasticization pressure and permeability at plasticization pressure were estimated to be 41.07 bar and 6.03 Barrer, respectively. The improved performance of the membrane is associated to the synergistic properties of the two layers prepared from different formulations of the same polymer. Thus, the dual‐layer flat sheet configuration displayed a potential in high pressure CO₂ removal from natural gas. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40924.