Abstract: In this work, the magnesia modified activated carbon (MgO-AC) adsorbent was characterized by scanning electron microscopy (SEM). The effects of co-existing anions on the MgO-AC adsorbent were investigated. The effects of adsorbent dose and solutions pH that influenced the sorption of anions and cations at the solid-liquid interface were also determined. The MgO-AC adsorbent could remove fluoride efficiently over a wide pH range of 5.00-8.00. The impact of major anions on fluoride adsorption followed the order of PO43− >HCO3− >SO42− >Cl− >NO3−.
Abstract: The effects of Cu addition on microstructure, mechanical properties and damping capacity of Mg-3%Ni based alloy were investigated by using tensile tests, X-ray diffraction, scanning electron microscope and dynamic mechanical analyzer. The results show that Cu addition could reduce the size of -Mg dendrites and a new binary phase Mg2Cu can be identified, which mostly distributes among the inter-dendrites in the form of typical lamellar-like eutectic microstructure and improve the mechanical properties. In low strain amplitude, with the increase of Cu addition, the damping capacities of Cu contained alloys change little, while in high strain range, the internal friction values decrease gradually with the grain refinement and increasing content of eutectic phase.
Abstract: The quality of modes of 3PE heat shrinkable sleeve is determined by tackiness of hot melt adhesive rather than aging, according to TGA and aging tests. The tackiness of hot melt adhesive influences on pipeline remaining life and the transmission safety of oil or gas. This paper mainly discussed how the tackiness is determined by hot melt adhesive moisture performance which depends on melt rheology and polymer polarity and offer basic information to further modification. Finally, this paper offers a choice data after such follow experiment. About rheology, apparent viscosity was tested by capillary rheometer and tackiness strength was measured by universal material testing machine. Those tests show that Eτ (Fe/Fe) raises and Ep(Fe/PE) increases at first then decreases with apparent viscosity increasing. About polarity, the polarity was tested by dynamic contact angle locator. This measurement indicates that the moisture improves with polarity increasing and tackiness increases at same time. Generally, the hot-melt adhesive apparent viscosity and polarity extend, consider to pipeline materials properties and oil or gas transmission condition, should hold at 450 Pa•s≤ηa (100°C ,20kg)≤520 Pa•s and 82.0°≤γ≤90.6°.
Abstract: The semiconductors have conductions ranged between the conductors and nonconductors. Conduction makes the semiconductors one of the most important materials for electric applications. Therefore, with the receiving pulses from cathode in different geometries such as Cartesian, cylindrical and spherical the most commonly used pulse is the pulse created by the detector with cubic geometry.
Abstract: To study the possibilities of volatilization in the asphalt pavement during service process, this paper presented an experimental investigation in the laboratory-based environment by simulating the circumstances of Infrared (IR) and Ultraviolet Radiation (UV). The Vacuum (Va) condition was also conducted to discuss the possibilities of volatilization in the asphalts. The changes of asphalt mass, chemical compositions and viscosity were conducted to analyze the experimental results. All the results on the circumstance of Va, that the decrement of asphalt mass, the decrement of light components and the increment of VI values, indicated that there may exist the volatilization in the asphalt. Different trends between IR and UV with asphalts demonstrate that the volatilization is affected by asphalt species and environmental conditions. In addition, ultraviolet radiation may take a vital role on the volatilization of asphalt.
Abstract: Three material properties (density, modulus of elasticity, bending creep deflection) of poplar wood modified with low molecular resin was examined and evaluated by an experimental approach. Poplar specimens were treated to achieve full penetration using a vacuum schedule with different low molecular resins. These resins were urea-formaldehyde (UF) and phenol-formaldehyde (PF) prepolymer solution. Creep tests were conducted under a varying climate with 16 °C ~ 31 °C and 40 % ~ 80 % relative humidity. The specimens were loaded in bending for approximately 140 days. Then the curves of the creep tests were analyzed to derive the development of bending creep performance. The results show modification leads to significant changes on material properties. Modification increases both the density and elastic modulus, and also tends to deflect creep deformation obviously less than untreated specimens.
Abstract: Experimental modal analysis is quickly developed area of science in last years. Experimental approach for solving technical problems is a means to estimate or evaluate modal properties of a mechanical structure. The paper is focused at dynamic properties of milling centers, namely at the resonance frequencies and vibration shapes of a simplified tool-work piece system. All this properties are identified by measurements. The machine tool vibration was excited by impulse force and a response of excited vibration was recorded. The measurement points for vibration were selected at the spindle head, the table and the clamping device. The paper aims to present comparative results of theoretical studies with experimental results obtained from impact test to the machining centers.
Abstract: Different final processing methods can bring about the difference in physical properties of metal materials, such as micro-structures, surface hardness, and residual stress. It can in turn influence the anti-fatigue performance of material. To compare the effects of two commonly used final processing methods on the properties mentioned above, two groups of smooth round bar specimens of LZ50 axle steel were utilized. The final machining process for the first group is finish turning, and that for the second one is surface rolling. Layer-stripping test results reveal that much higher residual compressive stress is engendered in surface and sub-surface of the rolling specimen. The surface micro-hardness of the first group is also higher than that of the second one. Furthermore, the micro-structures of these two kinds of specimens are somewhat different in local regions. Stress controlled fatigue tests were performed. The average fatigue life of surface rolling specimens is more than six times the life of finish turning ones. So the former final processing method is more suitable for improving the performance of present material.
Abstract: Over the last decades, there has been increasing global concern over the public health impacts attributed to environmental pollution. Natural materials that are available in large quantities or certain waste from agricultural operations may have the potential to be used as low cost adsorbent ,widely available and are environmentally friendly after using them. Thus, rice husk RH, a commonly available waste in Iraq. RH and activated rice husk ARH (pretreated by 13M H2SO4 with 0.5 NaOH and thermally treated at573k) have been studied as sorbents for heavy oil cleanup operations in the aqueous environment (water pumped from brooks to sedimentation unit). Batch adsorption experiments were performed as a function of pH (2-10) , adsorbent dose(0.25-1g ), initial concentration (1-20g/100ml water) , agitation time (15-75min) and different temperature(298-338K),with100rpm.The maximum removal took place in the pH range of 8, adsorbent dose 1g ,initial concentration 20g/100ml water , agitation time 45 min and temperature 338k . The sorption data obtained from studies at optimized conditions have been subject to Freundlich and Langmuir isotherm studies .The data fits well to both the Freundlich and Langmuir isotherm models indicating favorable and monolayer adsorption .X-ray diffraction analysis ,which indicates that the RH and ARH mainly consist of amorphous materials .The adsorbents were characterized using FTIR . It was found that the pretreatment of rice husk increase the specific surface area and changed the functional groups , therefore leads to increase the capacity of adsorption.
Abstract: The low cycle fatigue (LCF) behaviour of aluminium-magnesium-silicon alloy AA6061 processed by equal channel angular pressing (ECAP) was studied. Solutionized specimens of the alloy were subjected to one, two and three passes of ECAP at room temperature using route Bc. Compared to the values of the solutionized material an overall increase in yield strength and ultimate tensile strength with decrease in % elongation is observed for the ECAP processed material. While the solutionized material exhibits cyclic hardening at all strain levels, the ECAP processed material shows different behaviour depending on the number of passes - stable response/cyclic softening/ softening followed by hardening. The ECAP processed material after three passes exhibit superior LCF lives at low strains presumably due to higher strength and large refinement of grains.