Yu Lan Tang

Effect of Temperature on Electricity Generation of Single-Chamber Microbial Fuel Cells with Proton Exchange Membrane

The effects of temperature on electricity performance and microbial activity were investigated in single-chamber microbial fuel cell with proton exchange membrane (S-PEM-MFC) using glucose as substrate with phosphate buffer solution(PBS). The results showed that S-PEM-MFC able to adapt to a wide temperature range of 11, 18, 25, 30 and 35°C. The open circuit voltage, polarization, power density and microbial activity of S-PEM-MFC were increased with increasing temperature from 11 to 30°C. The maximum power density were 193.8mW∙m-3 at 30°C. Compared to 30°C, the battery open circuit voltage increased by only 4.8% at 35°C, while the polarization and power density is almost the same. These results demonstrate that according to the principle of economy which 30°C should be the optimal operating temperature of S-PEM-MFC.

Low-Temperature Domestication of an Iron and Manganese Oxidizing Bacteria

Abstract.One superior iron and manganese bacteria were separated from the stable operation of porcelain granular BAF filters of removing iron, manganese and ammonia. The bacteria was domesticated at low temperature. By analyzing the sample water containing iron and manganese in the role of iron and manganese bacteria which was not domesticated and domesticated at different temperature, observing the Iron and manganese concentration with time going on, studying the bacteria’s removal of iron and manganese property and the domesticated effect. Studies show that: the selected bacteria with 1% bacterial liquid at proper temperature within 48h ,the removal rate of iron and manganese was 75% and 35% respectively;After domesticated at low temperature, the removal rate of the iron and manganese domesticated bacteria at 10°C was improved 0.4 and 2 times more than the before domesticated; The iron and manganese domesticated bacteria at 10°C did not grow at 4°C,but the bacteria’s removal rate was better than the bacteria cultured at 30°C,and the iron removal rate was improved from 23% to 35%,the manganese removal rate was improved from 5% to 11%.

Research on Heavy Metal Pollution Sudden Emergency Processing Method in Water Environment

The paper introduced the source and harmfulness of heavy metal pollution in water environment and summarized the applications of the chemical method, physiochemical method and biological method in heavy metal pollution of sudden emergency accident. Meanwhile, the heavy metal pollution emergency processing technology of rivers, lakes and other water bodies were elaborated and the emergency engineering technology of heavy metal pollution in rivers and lakes were analyzed. Finally, the application of bioremediation on heavy metal pollution caused by sudden emergency accident was prospected.

Effect of Anode with Pretreatment on the Electricity Generation of a Single Chamber Microbial Fuel Cell

Electricity can be generated during the wastewater treatment by microbial fuel cell (MFC). Effect of the anode pretreatment method, anode modification and electronic media in anolyte on electricity generation of a single chamber microbial fuel cell (SCMFC) with an air cathode was investigated by performance measurement of the MFC during one cycle of generating electricity. Results show that the discharge time of MFCs with stainless steel anode pretreated by NH4Cl and HCl is longer than that with anode pretreated by the distilled water and NaOH; the performance of MFC with anode pretreated by NH4Cl is the best; comparison with stainless steel anode and adhere activated carbon, the current of MFC with the stainless steel anode adhere the carbon fiber is the maximum and its Coulombic efficiency is the highest; The electricity generation characteristics of the MFC with the anode adhered carbon fiber and pretreated by NH4Cl and the anolyte added the electronic media is the best. The action of the electronic medium and the NH4Cl on the MFC is synergism. Its of great significance that the research results improve the performance of MFC by anode pretreatment.

Establishment of the Lakes and Reservoirs’ Model

This article describes the simulation method of water temperature and the model classification of water quality in lakes and reservoirs, and classic model of ecosystem dynamics of lakes and reservoirs - BA model from the water quality parameters of the relationship between two aspects of the basic equations are introduced. On this basis, establish the eutrophication of ecological models of lakes and reservoirs.

The Simulation Study of Si3N4 Ceramics Nano-Cutting Process

Silicon nitride nanoscale cutting model was established by molecular dynamics simulation, and interactions force between atoms of work-piece was calculated by Tersoff potential function. Through the three-dimensional simulation of silicon nitride nanocutting process, the changes of cutting force, kinetic energy and potential energy in the nanoscale cutting process, and the effects of cutting thickness and cutting speed on the entire cutting process were analyzed. The results showed that the kinetic energy, potential energy and cuting force increased along with the cutting thickness increasing, both kinetic energy and potential energy decreased with cutting speed increasing.

Effect of Machining Parameters on Nano-Cutting of SiC Ceramics

SiC ceramics is very promising to be widely applied due to the excellent physical and chemical properties.However, the very difficult process of SiC ceramics hinders its application. In this paper, the nano-cutting of SiC ceramics is simulated based on molecular dynamics. The influences of the tool rake and cutting depth on the cutting force, the kinetic energy and potential are analyzed. The results show that the cutting force, system kinetic energy and potential energy increase firstly,reach the maximum, and then decrease in the process; with the increase of the tool rake, the cutting force and the kinetic energy decrease; with the increase of the cutting depth, the cutting force increases, and the kinetic energy and the potential energy decreases. These results are very helpful to understanding the process mechanism of SiC ceramics and increasing its process efficiency

Simulation of Nano-Indentation of Nano SiC Ceramic Micro-Component

A 3D model of molecular dynamics for nanoceramic SiC is adopted to simulate the hot pressing sintering and preparation process of SiC, and mechanical properties such as density, hardness and elastic modulus are calculated. Finite element model of indentation is established based on the mechanical performance parameters from MD simulation. Conical indenter is adopted in indentation simulation. The FEM simulation results show that: Maximum equivalent stress appears at the place of indenter tip, and equivalent stress curves are appeared hemispherical. As indentation depth increases, the stress increased. As the distance of away from the indenter increases, the displacement in equivalent displacement nephogram gradually decreased until zero. During unloading process, elastic restitution is occurred. The elastic restitution in the area of below the indenter is obviously. Residual stress in the center of indentation is maximal after unloading.

Effect of Surface Relaxation on Characteristics of Nanomachined Surface

With the development of Micro-electro-mechanical systems (MEMS) and Nano-electro-mechanical systems (NEMS), dimension of their parts is required to nanometer scale, and the characteristics of machined-surface of nano-scale parts affect strongly its application. Surface relaxation plays an important role to the characteristics of the machined-surface. In this paper, machined-surface of monocrystal copper used as the specimen of surface relaxation, and its surface relaxation process is simulated. The influences of surface relaxation on surface energy, atom array, surface roughness, surfaces hardness and surface residual stress of the monocrystal copper are analyzed. Results show that surface energy and surface hardness decrease due to relaxation; work-hardening can’t be completely eliminated by the relaxation; compression residual stress of the machined surface is changed gradually to tensile stress during the relaxation. These research results are very helpful to the application of nano-machined parts.

Nano-Process of SiC Ceramics by Molecular Simulation

SiC ceramics have been widely used in a variety of areas due to the excellent physical and chemical properties. However, the process of SiC ceramics is difficult and high-cost, molecular simulation is an effective and feasible method to study the nano-process of SiC ceramics. In this paper, a molecular model is presented to simulate the stress and energy in the nano-cutting of SiC ceramics. The influences of the cutting depth and cutting speed on the kinetic energy and potential are analyzed. The results show that potential energy increases with the decrease of the cutting depth. Kinetic energy increases with the increase of the cutting speed. The results are very helpful for improvement the level of ultra-precision processing and nano-processing of brittle ceramics.