Effects of NH4+, Na+, and Mg2+ ions on the corrosion behavior of galvanized steel in wet–dry cyclic conditions

The effect of cations on the corrosion of galvanized steel (GS) is scarcely reported. In this study, a wet–dry cyclic test was conducted to study NH₄ ⁺, Na⁺, and Mg²⁺ cation effect on the corrosion behavior of GS available in Nepal. Fourteen wet–dry cycles (18 h wet and 6 h dry) were performed by exposing samples at 298 K with a relative humidity of 90% in a wet cycle and 50% in a dry cycle for 14 days. The cations strongly affect the corrosion rate of the GS sample estimated by weight loss and potentiodynamic polarization. The potentiodynamic polarization curves showed the inhibition of cathodic and anodic reactions by Mg²⁺ ion, while the NH₄ ⁺ ion only changed the cathodic reaction. Mg²⁺ ion was found to shift the corrosion potential to noble values compared with NH₄ ⁺ and Na⁺ ions. A compact and thin corrosion products layer was developed in Mg²⁺ salt solution in contrast to a thick and porous corrosion products layer in NH₄ ⁺ and Na⁺ salt solutions. Red rust due to corrosion of underlying steel appeared in the presence of NH₄ ⁺ and Na⁺ salt solutions. Finally, the weight loss data revealed that the corrosivity of cations for GS decreased in the order Na⁺ > NH₄ ⁺ > Mg²⁺.     

Degumming rice bran oil using phospholipase‐A1

The efficacy of enzymatic degumming was assessed using the third generation phospholipase‐A₁, Lecitase®‐Ultra (EC 3.1.1.3) from Thermomyces lanuginosa/Fusarium oxysporum with different qualities of crude rice bran oil. The phosphorus content in the oil reduced to ～10 mg/kg from an initial level of 390 mg/kg after 2 h of incubation period at 50°C. However, in the solvent‐phase degumming, there was practically no phospholipid reduction at lower water content (2%) due to the poor contact between the highly nonpolar solvent and the aqueous phase (citric acid, NaOH, and enzyme solutions). Increasing the water content to 20% reduced the phosphorus level in the degummed‐oil to 71 mg/kg but did not match the performance of oil‐phase degumming. The degumming efficiency of Lecitase®‐Ultra was effective in oil‐phase and suitable for practical application. Solvent‐phase enzymatic degumming offers more benefits but needs greater efforts to overcome the challenges.     

浅析建筑与景观的空间构成关系——以港口中国博物馆景观设计为例

本文以中国港口博物馆景观设计为例,分析了建筑与景观的空间构成性质和特点,从建筑界面、空间限定要素、空间氛围与植物配合三个层面上论述了建筑与景观的内外连续性、建筑空间限定要素在构成上的拆解、建筑与景观空间氛围的整合与植物造景对建筑空间的柔化,进而阐述了建筑与景观的空间构成关系。     

A virus-based nanoblock with tunable electrostatic properties

Five different "HIS tag" mutants of cowpea mosaic virus were made by genetically introducing six contiguous histidine residues at various locations on the virus capsid. The mutant particles showed differential affinity for binding nickel, and their electrostatic properties could be controlled as a function of the protonation state of the exposed histidine sequence. The specific addressability of the HIS tag was corroborated by the selective modification of the histidine sequence with nanogold cross-linked to the Ni-NTA moiety.     

Mean free path effects in superfluid4He

The mean free path effects in superfluid He II was studied with a vibrating wire method in the temperature range from T down to 20 mK under the saturated vapour pressure. The transition from the hydrodynamic regime to the ballistic regime was clearly observed at around 0.7 K with a 47 µm diameter wire. In the hydrodynamic regime the usual Stokes' approximation was found to be insufficient to interpret the results. In the ballistic regime the results can be explained quantitatively with the kinetic theory of phonons. However, below about 0.15 K there appear non-linear effects such as the distortion of the resonance line shape and a hysteresis behavior, which become stronger with decreasing temperature.     

Enhancement and Modeling of Drain Current in Negative Capacitance Double Gate TFET

Silicon - The drain current improvement in a Negative Capacitance Double Gate Tunnel Field Effect Transistor (NC-DG TFET) with the help of Heterojunction (HJ) at the source-channel region is...     

Development of autonomous gamma dose logger for environmental monitoring

Continuous monitoring and archiving of background radiation levels in and around the nuclear installation is essential and the data would be of immense use during analysis of any untoward incidents. A portable Geiger Muller detector based autonomous gamma dose logger (AGDL) for environmental monitoring is indigenously designed and developed. The system operations are controlled by microcontroller (AT89S52) and the main features of the system are software data acquisition, real time LCD display of radiation level, data archiving at removable compact flash card. The complete system operates on 12 V battery backed up by solar panel and hence the system is totally portable and ideal for field use. The system has been calibrated with Co-60 source (8.1 MBq) at various source-detector distances. The system is field tested and performance evaluation is carried out. This paper covers the design considerations of the hardware, software architecture of the system along with details of the front-end operation of the autonomous gamma dose logger and the data file formats. The data gathered during field testing and inter comparison with GammaTRACER are also presented in the paper. AGDL has shown excellent correlation with energy fluence monitor tuned to identify (41)Ar, proving its utility for real-time plume tracking and source term estimation.     

Role of Bi-excess on structural,electrical, optical,and magnetic properties BiFeO3 nanoparticles

Journal of Materials Science: Materials in Electronics - The influence of Bi content on structural, optical, and multiferroic properties of BiFeO3 has been studied. The nanoparticles of BiFeO3 with...     

A comparison of single and multiple strategy instruction on third-grade students' mathematical problem solving.

The purposes of this study were to assess the differential effects of a single strategy (schema-based instruction; SBI) versus multiple strategies (general strategy instruction, GSI) in promoting mathematical problem solving and mathematics achievement as well as to examine the influence of word problem-solving instruction on the development of computational skills. Eighty-eight 3rd graders and their teachers were assigned randomly to conditions (SBI and GSI). Students were pre- and posttested on mathematical problem-solving and computation tests and were posttested on the Pennsylvania System of School Assessment Mathematics test, a criterion-referenced test that measures student attainment of academic standards. Results revealed SBI to be more effective than GSI in enhancing students' mathematical word problem-solving skills at posttest and maintenance. Further, results indicate that the SBI groups' performance exceeded that of the GSI group on the Pennsylvania System of School Assessment measure. On the computation test, both groups made gains over time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)