Applied Mechanics and Materials Vols. 71-78

Abstract: A new modified organo-bentonite using dithizone(D-O-bentonite) was used for preconcentration, separation and determination of silver(I) in natural water by flame atomic absorption spectrometry (FAAS). The experimental conditions for effective adsorption and elution of trace levels of silver (I) were optimized with respect to different experimental parameters. The influences of some common coexisting ions were also examined. The results show that the silver ion could be adsorbed on the D-O-bentonite. The adsorbed quantitively was affected by the pH value of medium and contact time. In the medium of pH 4-8, the contact time was 15 min, and capacity of the sorbent was 19.7 mg·g^-1. The silver(I) adsorbed on the sorbent could be completely eluated by using 1 mol·L^-1 HNO₃. The preconcentration factor is 100. The detection limit of the method for silver was 0.02 µg·L^-1. The method was applied to the pre-concentration/separation of silver in the environmental water with satisfactory results.

Abstract: The adsorption capability of nano-barium-strontium titanate coated by dithizone(BST- dithizone) for mercury in environmental water samples was studied. The optimum experimental parameters for the adsorption and desorption of the mercury, such as pH values, contact time and eluent, have been investigated. The results showed that the mercury ion in water could be adsorbed on the BST- dithizone. The adsorption capability was affected by the pH value of medium and contact time. In the medium of pH 3-8, the adsorption time was more than 15 min, and capacity of adsorption was 15.3 mg·g-1. The used adsorbent could be completely regenerated using 2 mol·L-1 HNO3. A new method for the removal of mercury in water samples was proposed. The method has been applied to the removal of mercury in waste water samples with satisfied results.

Abstract: The indoor thermal comfort and its effect on building energy consumption have been conducted by literature reviewing in the study. The linear relationship and the related formulations of various thermal comfort indictors are summarized to evaluate the human comfort. These parameters include predicted mean vote, thermal sensation vote, adaptive predicted mean vote, thermal comfort vote, and thermal acceptability. Under different climatic or regional conditions, both relationships between thermal comfort parameters and indoor or outdoor air temperature, and between comfort vote and another comfort parameter, are summarized for their definition and formulation. The comfort parameters such as local air speed, neutral temperature, PMV set point and others will directly impact the building energy usage. It is of significance to seek an optimal alternative for energy savings.

Abstract: This study reviews some published literatures on the benchmarking and ranking guidelines, tools and comparison of buildings. Energy performance, Indoor air quality and thermal comfort can be covered for the rating tools for buildings. Further, the energy performance can also be calculated by the other parameters related to the room thermal properties. A rating system to benchmark buildings can employ several parameters including indoor environment quality, clothing volume, predicted mean vote, operative temperature, and thermal energy consumption. It can be concluded that the indoor air quality or thermal comfort can be used to evaluate buildings due to their influence on the occupant satisfaction and job performance. Also, building benchmarking or rating will be various because Different comfort criteria may lead to different comfort temperature.

Abstract: The magnetized water which is used to mix concrete can improve the performance of concrete. This paper presents the effect of magnetized water on performance of sprayed concrete in laboratory, also carries out the changes of dust concentration and rebound rate of sprayed concrete mixed with magnetized water in mine roadway. The results indicate that the early strength of concrete mixed with magnetized water has been obviously improved and the dust concentration and the rebound rate can be effectively reduced while spraying concrete.

Abstract: To promote the enterprise of wind power generation, optimize the structure of wind power tower and improve the generating efficiency, a mini-type timberwork wind power generation tower model was designed and fabricated. Based on the tests by the leeward loading scheme, static characteristics and dynamic characteristics of the model were analyzed by numerical simulation. The results calculated through the finite element simulation were in a reasonable agreement with the test results. Additionally, considering the impact of different load levels, the bearing capacity, stiffness and the dynamic behavior can meet the requirements, which has significant reference value on practical application.

Abstract: In this study, we can measure the permeability of Marshall specimens by modified osmotic pressure meter, which is improved by osmotic pressure meter. We get different voidage Marshall specimens and rutting plates by changing compaction times and rolling times. Modified osmotic pressure meter measures the permeability of Marshall specimens. Pavement ooze water meter measures the permeability of rutting plates. The results showed that: Because of the internal air, side sealing and different formula, the permeability coefficient measured by Pavement ooze water meter is not accurate. Modified osmotic pressure meter eliminates many adverse effects when we measure the permeability of asphalt mixture. So the correlation of voidage and permeability coefficient is better.

Abstract: Bronze powders were prepared using high-energy ball mill method. Effects of different additives on particle size and its distribution, gloss, water coverage and oxidation resistance of powders were discussed. The results shows that aluminum stearate has a great impact to sheet formation of bronze powder. Hexadecanoic acid has a great influence on the gloss and water surface covering. Polyvinyl alcohol(PVA) has a marked effect to improve oxidation resistance of the bronze powders.

Abstract: Besides live loads like cars,earthquakes and people,wind loads should not be neglected on small bridges in mountainous areas,especially by taniguchi and mountain pass.This text does an analogue computation taking a typical slant legged rigid frame bridge in a mountainous area of Chongqing. This bridge lies in the taniguchi of mountainous area where wind condition is complicated.Mathematical model conforming to the local wind load should be established according to the meteorological and hydrological conditions of the bridge site and hydrodynamics and energy conservation principle in order to truly reflect the actual condition of wind in bridge site. Comparing with the calculating result by ANSYS and model of static wind load for normal design, it shows that model of fluctuating wind load established almost accords with the model of static wind load which provides a new train of thoughts and method for further promoting the model of wind load to lead the wind-resist design of bridge construction of taniguchi in mountainous area to better approximate to the real facts.

Abstract: To obtain a faster response speed and higher synchronization accuracy, the paper firstly discusses the difficulties and disadvantages of organizing servo motion network with traditional fieldbus. Then, a novel method for constructing multi-axis motion system based on EtherCAT is presented. With DSP and an improved PID control algorithm, the hardware and software design is introduced in details. The system has realized high-speed remote data transmission and high-precision velocity control for Multi-axis which the traditional fieldbus can’t achieve.