Control of Snow Falling Flow around NACA0015 Blade using a Plasma Electrode with Weather Resistant Design

The plasma actuation (PA) effect on the snow falling flow was investigated using a plasma electrode with weather resistant design and the natural snow wind facility of the Hokkaido University of Science. NACA0015 test blade with chord length c of 300 mm was used. Wind tunnel tests were carried out under the angle of the attack of the blade was fixed at 15 degrees, and the main flow velocity is U=5 m/s. PIV (Particle image velocimetry) measurements were conducted on various PA conditions using natural dry snowflakes as a tracer. When the actuator was driven under the condition of the fundamental frequency of F=50 kHz, and the pulsed modulated frequency f of fc/U=1 and Duty ratio (Ratio of plasma ON time to pulse duration time) =1%, movement of snowflakes was controlled the most effectively tested. It was clarified that the fundamental frequency of PA also affects the control of snow flow. Under snowfall conditions, the weather resistant designed plasma electrode has suffered no damage and operated successfully.

Study Correlation between Physical-Mineralogical Properties of Sandstone Used in Ptolemaic Temples in Upper Egypt and Its Weathering Resistance

This article focuses on study of a relation between physical-mineralogical properties of sandstone used in Ptolemaic temples in Upper Egypt and its resistance of deterioration factors affecting it. In the present study, sandstone samples were collected from four sites;namely the temples of Dendera, Esna, Edfu and Kom Ombo which are located in Upper Egypt. Polarized light microscope (PLM), Scanning Electron Microscope (SEM), X-Ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX) were used to determine mineralogical properties, microstructure, and chemical compositions of the deteriorated sandstone samples, addition to physical properties tests;results of the study confirmed that sandstone samples containing a high percentage of salts, clay minerals and iron oxides have been significantly affected by deterioration factors. The deteriorated sandstone samples were treated by paraloid B72 3% enhanced with Nano silica 5% to improve the physical properties of stone. Results of the study indicated that the samples which were consolidated by Nanoparticles based on acrylic Copolymers (Paraloid B72 and its Nanocomposite with Nano silica) achieved the best results for improvement of its physical-mineralogical properties. This is the ultimate aim of the study for the purpose of conservation and sustainability of building materials of the temples.

Effects of neodymium and gadolinium on weathering resistance of ZnO-B_2O_3-SiO_2 glass

The ZnO-B203-SiO2 glass doped with Nd2O3 and Gd2O3 was prepared by high temperature melt cooling method. The standard sample of the zinc borosilicate glass was placed in the constant temperature and humidity chamber in order to simulate the atmospheric corrosion process. The surface of the weathered glass was analyzed by scanning electron microscope and energy disper- sive spectrometry and the filtrate was analyzed by inductively coupled plasma-atomic emission spectrometry. The results showed that humidity was the most important factor influencing weathering; the morphology of glass surface of altered layer and the product on the surface was observed; the corroding degree of the zinc borosilicate glass doped with Nd or Gd was significantly lighter than that of the base glass. Adding rare earth Nd or Gd in the zinc borosilicate glass could suppress Na, Zn, Si ion release in weathering.

Corrosion Behavior of S450EW Low-alloy Weathering Steel in Cyclically Alternate Corrosion Environments

Weathering steel is widely used in various fields due to its excellent mechanical properties and high corrosion resistance. The effect of chromium content on the S450 EW weathering steel in cyclic immersion test was studied. The results indicated that the corrosion resistance of S450 EW weathering steel is closely related to chromium content. The addition of chromium significantly inhibited the weathering steel corrosion. The corrosion rate of experimental steel after 96 h immersion was 1.101 g·m-2·h-1. The rust of S450 EW weathering steel was mainly constituted of Fe OOH and Fe3O4 phase, and the elevation of chromium content promoted the formation of α-Fe OOH. The fine precipitates of the two phases contributed to the formation of dense dust layer of test steel. Furthermore, the increase of chromium is beneficial for the cure of original defects and cracks of the rust layer via the enrichment of chromium. The corrosion potential and the resistance of corrosion process were thus increased, protecting the experimental steel from further corrosion. A S450 EW steel with corrosion resistance more than 1.5 times of Q450NQR1 steel was prepared.