bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Energy Consumption and Mode of Energy Saving of Rotary Wheel
Authors: Yue Ming , Ding Yun Fei , Wu Hui Jun
Published: October 2011

A model of rotary wheel combined with heat pump regeneration was presented and an experimental investigation on it was also carried out. Five normal kinds of dehumidification efficiency evaluation standard were introduced in view of the existing various dehumidifying method while the current energy efficiency evaluation indices were analyzed. SMER which defines the dehumidification quantity of unit energy consumption and dehumidification system energy efficiency were introduced and used to compare energy consumption of rotary wheel with or without heat pump. The comparative analysis showed that the system of rotary wheel combined with heat pump regeneration could significantly improve SMER and dehumidification system energy efficiency of rotary wheel.
Static and Dynamic Analysis of the Air-Cooled Condenser Platform Structure in Thermal Power Plant
Authors: Jiang Li Yun , Chu Jian Xiang , Cao Yu Sheng
Published: October 2011

Direct Air Cooled Condenser (ACC) has advantages of energy conservation, convenience repair and low production cost. An air-cooled platform structure is designed considering load conditions and the structure’s mechanical characteristics, a finite element model of the ACC platform is set up and static and dynamic analysis are made. The static analysis result shows that the maximum displacement meets the requirements of the structure’s normal use and the industrial equipment’s normal operation; the dynamic analysis result shows that the structure’s overall performance is excellent, the vibration mode of the structure and free period of vibration are reasonable. Based on the model analysis, the quality model, the stiffness model and the relationship between them are discussed.
Measuring and Analysis on Energy Consumption of Variable Air Volume (VAV) Central Air-Conditioning System
Authors: Ren Qing Chang , Guo Shang Yi , Lei Xiao Feng , Yan Wei Jia
Published: October 2011

With the development of urbanization, the building energy conservation has been paid more and more attention, and 50% to 60% of the power energy consumption—the energy consumption of air-conditioning be paid attention for people. Research about measuring and analysis on energy consumption of VAV air-conditioning system is described in this paper. A measuring and analysis solution has been implemented in the VAV Air-Conditioning laboratory of Xi’an University of Architecture & Technology (XAUAT). The satisfactory results are given.
Experimental Study of the Compressor for the HFC125 Heat Pump
Authors: Wang Feng Kun , Fan Xiao Wei , Wang Fang
Published: October 2011

To study the performance of the compressor in the HFC125 heat pump system, the volumetric and isentropic efficiencies of a variable speed compressor with pendular pistons were measured with the developed experimental system of HFC125 heat pump in the frequency range of 15-115Hz. The result indicted that there were high volumetric and isentropic efficiencies for the compressor in every frequency. A new model for the calculation of volumetric efficiency and isentropic efficiency were proposed in this paper, and the 146 experimental data of the volumetric and isentropic efficiencies were fitted with the new model. For the volumetric and isentropic efficiencies, the average absolute deviations were 1.749% and 2.815%，respectively, and the maximum deviations were 5.397% and 6.793%, respectively. It could be known that the new model could describe accurately the performance of the variable speed compressor with pendular pistons.
Study on the Adjustment Law of Supply Water Temperature of the Fan Coil Unit Based on Daily Air-Conditioning Load
Authors: Gao Zhi Jie , Wang Zhi Wei , Zhao Ji Feng
Published: October 2011

A new adjustment law of supply water temperature of heat pump unit was presented by analyzing heat transfer performance and computing supply water temperature of fan coil unit (FCU) in this paper. The paper established the energy equations for air side, water side and FCU in dry and wet conditions, respectively. And the heat transfer performance of FCU was obtained by analyzing the manufacturers’ performance data. According to an actual central air-conditioning system of residential buildings, we calculated the daily inlet water temperature of FCU and proposed the adjustment law for supply water temperature. The results show that the supply water temperature of cooling design day is 9.3°C, the daily supply water temperature of cooling season is higher than 7°C; the supply water temperature of heating design day is 36.4°C, the highest in heating season is 38.5°C, which is below the rated supply water temperature of heat pump unit, 45°C.
Simulation and Optimization of Denitrifying Phosphorus Removal in A2/O
Authors: Ai Hai Nan , Li Mao Lin , He Qiang
Published: October 2011

The GPS-X was used to simulate the denitrifying phosphorus removal in the A2/O.The improvement actions were obtained due to the simulation result.Moreover, the effect of denitrifying phosphorus removal was forecasted after the application of optimization and improvement. The prediction shows that: by adjusting the operating parameters such as SRT was adjusted to 15ds, the internal reflux ratio was adjusted to 300% and the external reflux ratio was adjusted to 100%,the denitrifying phosphorus removal in the A2/O was obviously increased. Therefore, the employment of GPS-X software in simulation and optimization can provide guidance for the operation and control in wastewater treatment plants.
Test Analysis on Flow Field of Exhaust Hood in Commercial Kitchen
Authors: Jiang Da Hua , Li An Gui , Shi Fa En , Zhao Yu Jiao
Published: October 2011

Making exhaust hood model in laboratory according to exhaust hood in commercial kitchen, steam instead of fume, and characteristics of flow field are studied in kitchen exhaust hood. The distribution of velocity and temperature at typical planes was measured at valve opening of 45 degrees when water boiling. Results show that in a certain range, air velocity of exhaust hood decreases when air from the exhaust opening distance increases, velocity reduces with x and y increasing, steam velocity reaches maximum value close to exhaust outlet of fan.
Experimental Study on Variable Load Ratio Characteristics of a Multi-Split Air-Conditioning System in Summer Condition
Authors: Nan Xiao Hong , Wang Jian Ying , Yang Mei , Li An Gui
Published: October 2011

This paper studies the variable load ratio characteristics by experimental methods for the multi-spilt air-conditioning system K-1, which is installed in school of Environmental and Municipal Engineering of Xi’an University of Architecture and Technology. The temperature changes along with the refrigerant liquid pipe were tested under different partial load ratio conditions in summer. Experimental results demonstrate that the liquid refrigerant temperature for outdoor unit at outlet increased with the increment of the load ratio. On different load ratio conditions, the liquid refrigerant temperature decreased rapidly along refrigerant vertical pipe and turned to change slowly along horizontal pipe. When load rate is between 50% and 80%, energy efficiency ratio (EER) value is relatively high, about 2.63~2.84. EER value reaches a maximum of 2.84 with 65% load ratio.
Model Experimental Study on Stratified Air Distribution with 2D-PIV for High Ceiling Industrial Plant
Authors: Shen Jian , Li An Gui , Zhao Yu Jiao
Published: October 2011

At present, the research ways of stratified air-conditioning technology mainly have two types, experimental study and numerical simulation. In this paper, a transparent Plexiglas model was designed, of which the size was supposed to be 1/50 of the real scale. PIV technology was innovatively applied into the experiment to measure the air distribution of an industrial plant. Different air supply velocities and different kinds of air supply outlets were taken into account to discuss the influence of them. Results revealed that as the jet velocity increased gradually, the airflow’s stratification effect became more evident. When the aspect ratio changed from 1:2 to 1:8, the diffusion degree in vertical direction increased obviously. In comparison with the rectangular air supply outlet, the circular one had lower decay, longer jet distance and better contractibility. The experimental findings are useful for optimizing the design of air distribution in high ceiling industrial plant.
Experimental Study of Local Heat Transfer Coefficient of R113 Flow Boiling in Vertical Square Tube
Authors: Sun Wei , Guo Ya Jun , Bi Qin Cheng , Gao Bin , Xu Ying Kun
Published: October 2011

This article is based on the experimental investigations on flow boiling heat transfer of R113 with the equivalent diameter of the square tube 15.66mm, mass flow rate 500 ~ 2000kg / (m2•s), steam quality from 0.1 to 1, heat flux 50 ~ 90kW/m2, and pressure 100 ~ 250 kPa. The experimental results show that with the rise of heat flux and mass velocity the local convection heat transfer coefficient increases, and with the enhancement of steam quality the local convection heat transfer coefficient increases firstly and then decreases. By comparison of the experimental data and the calculation results of predecessor’s correlations, a correction coefficient applicable to this experiment was obtained.
The Feasibility Research of Temperature and Humidity Independent Controlled Air-Conditioning System in Textile Factory
Authors: Di Yu Hui , Yu Fu Tao
Published: October 2011

The demand of temperature and humidity in textile factory is higher, in order to be able to accurately independent control temperature and humidity and solve the problem of excessive consumption of energy, Introduce the temperature and humidity independent controlled air-conditioning system (THIC). The enthalpy-humidity chart of the air-conditioning process and energy cost are analyzed and compared for the air-conditioning. It indicates that THIC not only can satisfy the production process requirement, and can use low grade energy and reduce energy consumption.
The Energy Efficiency Reconstruction and Energy Consumption Assessments about a Library in Guangzhou
Authors: Chen Liu Zhi , Xu Xiao Ning , Liu Han Wei
Published: October 2011

How to reduce the energy consumption of the central air-conditioning is important for the building energy efficiency. The energy efficiency reconstruction of the central air-conditioning system on one library in Guangzhou is completed with the network control system self-developed. The operational control and operational management is integrated in the network control system. The energy consumption before and after reconstruction about the air-conditioning system of the library is detected and analyzed in the paper. The result shows the mode that operational control and operational management integrated has better energy efficiency.
Polycyclic Aromatic Hydrocarbons in Surface Sediments of Northern Taihu Lake and the Coupling with the Environment
Authors: Shi Long Qing , Cheng Jian Guang , Wu Jian Jun
Published: October 2011

This research mainly is about the ecological risk and the distribution features of the PAHs in the sediment of Taihu lake as well as the source of PAHs by studying 38 sediment samples of the Taihu Lake. The results show the 16 PAHs which the United States Environmental Protection Agency (EPA) released as priority pollutants in sediments were detected in sediments of Taihu Lake .PAHs in surface sediments at the study area are mainly from the combustion of wood and coal and pyrolysis of fossil fuels; high ring compounds, on behalf of fossil fuels, on the conditions of pyrolysis and high temperature, accounts the total of PAHs for 75.1%.The ecological risk of PAHs is relatively low in surface sediments at the study area, but the river estuary Naphthalene, Acenaphthene, Acenaphthylene, Fluorene, Phenanthrene, Anthracene, at partial the sampling points in the entry of the river, are exceeding to the corresponding TEL, may have a negative effect on the ecological environment.
Treatment of Leachate by Aged-Refuse Reactor in Natural Ventilation during Autumn and Winter
Authors: Luo Jie Yu , Sun Xiao Jie , Wang Dun Qiu , Zhu Yi Nian
Published: October 2011

The effect of temperature on two stage aged-refuse-based reactor which treats leachate in natural ventilation was investigated in autumn and winter. Results indicate that the average concentrations of COD in treated effluent increase from 726 mg/L in autumn to 2000 mg/L in winter in the first stage reactor while they are 246 mg/L and 1010 mg/L respectively in the second stage reactor. The average concentrations of NH3-N in treated effluent increase from 123.7 mg/L in autumn to 620 mg/L in winter in the first stage reactor while they are 123.7 mg/L and 620 mg/L respectively in the second stage reactor. Accordingly, the average removal rates of COD decrease from 81.7% of autumn to 73% of winter in the first stage reactor and decrease from 64.7% to 52% in the second stage reactor, and finally, the total COD removal rate in this system drops from 92.7% in autumn to 85.8% in winter. So we can conclude that the effect of temperature on the first stage aged refuse reactor is better than that on the second stage aged refuse reactor.
The Application of Radiant Concrete Ceiling’s Heat Storage in Wu Han, China
Authors: Li Na , Yuan Dong Li
Published: October 2011

In temperature and humidity independent control system, although the heat storage capability of the concrete ceiling is not big, for energy-saving building with small air-conditioning load, its potential of operating cost’ saving is not negligible. Based on an energy-saving dwelling building’s typical room in Wu Han, China, this paper dynamically analyzes the room’s load and concrete ceiling’s radiating capability, get conclusion that: according to the peak-valley electricity price and reasonable intermittent operation strategy, the temperature control system can save cost by 16.6% in summer, 27.3% in winter.
Study on the Solar Photocatalytic Degradation Characteristics of Phenol by the Double-Skin Sheet Reactor with Immobilized Catalyst
Authors: Li Jie Rui , Lin Shao Hua , Gu Zong Liang
Published: October 2011

A new type of a non-light concentrating solar photoreactor with immobilized catalyst was developed, where a flat and transparent structured box made of polymethylmethacrylate comprised the main body, and immobilized TiO2 membrane supported on glass fiber net with sol-gel method was used as catalyst. Phenol was used as model pollutant to evaluating the device performance. The limitation of mass transfer was diminished when the circular flux exceeded 2L/min. The apparent reaction kinetics was first order with respect to the phenol concentration, and the apparent kinetic constants decreased with the increase of initial concentration. The linear dependence between apparent reaction rate and radiation density flux was found from 12.8 to 47.6 W/m2. The new reactor, which treated phenol in tap water with high efficiency, has a promising prospective in real drinking water treatment.
Phosphate Removal and Recovery with Seed Crystals in Low Concentrated Phosphate Wastewater
Authors: Qiu Li Ping , Wang Guang Wei , Zhang Shou Bin , Yu Tao
Published: October 2011

The phosphate removal and recovery from lower concentrated phosphate wastewater with the quartz sand, ceramsite, blast furnace slag and steel slag as seed crystals were investigated. The results showed that the steel slag performed a better phosphate removal performance than the other threes. The phosphate crystallization occurred under the reaction conditions of Ca/P 2.0, pH 9.0, phosphate concentration 10 mg/L and reaction time 12h. The steel slag could be employed as an effective seed crystal, of which the phosphate concentration decreased drastically in 12h and almost had been removed completely in 48h. The XRD analysis showed that the main crystallization products were hydroxyapatite (HAP) and the crystallinity increased with the reaction time.
Efficiency of Copper Removal from Wastewater with Zeolite/EPDM Composite
Authors: Liu Xiu Qi , Xing He Qin
Published: October 2011

In our study, a new kind of material for Copper (Cu2+) absorbency was prepared by melt blending with EPDM as the matrix and modified zeolite as the filler. In order to overcome this obstruction, PEG-2000 was used as pore forming agent. By calculating, trial parameter n was 1.9, so, the composite was easy absorption. By SEM and XRD measurement, it was confirmed that the composite was more suitable as filler than the original zeolite and the acid modified zeolite. It can be showed that the pore forming agent adding was necessary and effective for the absorption by SEM micrograph of suction passage in EPDM and the composite.
Study on the Effects of Shear Strength and Aeration Method on Membrane Fouling in Vertical A/O-MBR Process
Authors: Chen Xiu Bo , Liu Zhi Qiang , Liu Xu Hua , Yu Gai Jing , Zhang Zhi Hua
Published: October 2011

Vertical Anoxic/Oxic Membrane Bioreactor (A/O-MBR) was used to treat domestic sewage. PVDF hollow fiber membrane has been used in MBR. According to the comparison of intercommunity between three non-Newtonian fluid models (Bingham model, Ostwald model and Herschel-Bulkley model) and the test data, the Ostwald model was chose to describe the function relationship between shear intensity and aeration amount. In order to initiating a circulation velocity and to enhancing the scour to the MBR, the traditional aeration method was changed in this experiment. Two baffles were placed on both sides of the membrane modules, and aeration heads were scattered between two baffles. The influence of shear intensity and new aeration method to membrane fouling was investigated in this paper at shear intensity of 20s-1, 40s-1, 60s-1 and 80s-1. The result shows that the stronger shear intensity is, the heavier is the MBR been scoured and the smaller is the change of TMP. The best shear intensity was G=60s-1 after considering all factors comprehensively. Finally, the membrane modules were analyzed by scanning electron microscope (SEM). By the SEM pictures we can see that there are some spots on the membrane surface which deposited by fine grains, EPS and SMP. The spots have different size and location, large scale or compact contamination layer can not been found in the pictures. So it indicates that the changing of aeration method and the controlling of shear intensity has a positive impact on slowing down the membrane fouling.
Biochemical Characteristics of UBAF in Different Influent NH4+-N Concentration under Yellow River Condition
Authors: Liu Jian Guang , Li Kai , Liu Hui , Feng Meng Meng
Published: October 2011

The upflow biological aerated filter(UBAF) filled with grain slag was applied in Yellow River treatment. The aim is to study the reactor’s ability withstanding ammonia nitrogen volumetric loading in Yellow River water treatment. As influent NH4+-N concentration increases from 0.2mg/L to 3.0mg/L, the average removal rate of turbidity, CODMn and NH4+-N were 82%, 27% and 97% respectively, and removal of NH4+-N occurs mainly in the filter layer depth changing from 150cm to 210cm. The nitrification performance improves when PO43- -P concentration in water reach 60μg/L, and the removal of NH4+-N occurs mainly in the filter media layer depth shortened from 210cm to 90cm.
Numerical Simulation of Shock Diffraction on Cartesian Grid
Authors: Chen Hong , Zhu Wei Bing , Sun Run Peng , Zhang Bin
Published: October 2011

Shock diffraction over geometric obstacles is performed on two-dimensional cartesian grid using the TVD WAF method in conjunction with the HLLC approximate Riemann solver and dimensional splitting. Present cartesian grid results for popular and challenging two-dimensional shock diffraction problems are presented and compared to experimental photographs. Benchmark and example test cases were chosen to cover a wide variety of Mach numbers for weak and strong shock waves, and for square and circular geometries. The results show that the comparisons between experimental and simulated images are consistent.
Applications of Carbon Fiber Composites
Authors: Zhu Cheng Li
Published: October 2011

Owing to the excellent properties, carbon fiber composites have been applied in many fields. This article outlined the new applications and development trends of carbon-fiber composite materials, and pointed out some problems existing in their development. Moreover, a new kind of billiard cloth made of the mixture of carbon fiber composites and wool was argued in the paper.
Magneto-Elastic Analysis of a Superconducting Film with a Crack-Like Flaw
Authors: Yong Hua Dong , Zeng Jun , Zhou You He
Published: October 2011

This paper analyzes the magnetoelastic response of type-II superconducting film. Cracks can lead to large local current enhancement near the crack-like flaw tips, Based on the previous work, the effects of the flaw on the stress field are discussed. It is found that the presence of the flaw markedly enhances the concentration of the stress near the tips of the flaw. In addition, as the geometry increases, the position where the maximum stress occurs increases.
Virtual Boundary Element Collocation Method with RBF Interpolation on Virtual Boundary and Diagonalization Feature in Fast Multipole Method
Authors: Si Wei , Xu Qiang
Published: October 2011

The algorithm idea of virtual boundary element collocation method with RBF interpolation on virtual boundary and diagonalization feature in fast multipole method is presented to study 2-D elasticity problems in this paper. In other words, the new fast multipole method (FMM) adopting diagonalization and the generalized minimal residual (GMRES) algorithm are jointly employed to solve the equations related to virtual boundary element collocation method (VBEM) with RBF interpolation on virtual boundary. In this paper, the numerical scheme suitable for original FMM with respect to two-dimensional problem of elasticity is optimized, through the introduction of concept of diagonalization, in terms of the radial basis function to express the unknown virtual load functions, in order to further improve the efficiency of the problem to be solved. Then large-scale numerical simulations of elastostatics might be achieved by the method. Numerical examples in the paper have proved the feasibility, efficiency and calculating precision of the method.
Influence of Soil Saturation on the Free Field Response of Liquefiable Soils
Authors: Liu Fu Sheng , Bian Han Bing
Published: October 2011

Free field response of partially saturated sands to cyclic loading, with a particular attention to soil liquefaction has been studied. The study has been conducted using a numerical model elaborated for the liquefaction of partially saturated soils together with a cyclic elastoplastic constitutive relation implemented in a finite element program. The numerical model and the analysis of the influence of soil saturation on the free field response, for different positions of the water table have been investigated respectively. The result shows that the soil saturation degree largely affects the free field response to cyclic loading, with a decrease in soil saturation leading to a decrease in the rate of generation of excess pore-water pressure, and consequently to a reduction in the liquefaction risk.
The Seismic Response Analysis of Continuous Rigid-Frame Bridge - Energy Method
Authors: Yu Qi Cai , Liu Ai Rong , Xiong Ren , Yu Hui Jun
Published: October 2011

A 3D Finite Element model of a continuous rigid-frame bridge is constructed by the Midas/Civil bridge finite element analysis program in this paper, where fiber elements and plastic hinges are used for bridge piers. The lump mass method is used to simplify the infinite-degree-of-freedom continuous rigid-frame bridge into a multi-degree of freedom model. The energy solution of continuous rigid-frame bridge is given, and the time-history analysis of the bridge is applied. In addition, the energy response of continuous rigid-frame bridge with different pier height and reinforcement ratio are given based on the energy method, revealing the impact of pier height and reinforcement ratio on the displacement and energy response of continuous rigid-frame bridge.
Effects of Site Classification on Platform Value of Response Spectrum
Authors: Li Ping , Bo Jing Shan , Guo Xiao Yun , Sun You Wei , Zhang Yu Dong
Published: October 2011

Regarding the design response spectrum in the code for seismic design of buildings as target spectra，the 28 acceleration histories are formed artificially．They are used as the inputs ground motion in earthquake response analysis．Four site classifications profiles were selected or constructed from practical site profiles．With the use of 1-D equivalent linearization wave motion method that is wildly used at present in site seismic response analysis, the platform values of surface response spectrum for different profiles under different ground motion inputs were calculated．Different platform values of the response spectrum and relational expression which is seven input earthquake motion intensity and site classifications have been given by statistical analysis.
The Anti-Bending Bearing Capacity Analysis of the Reinforced RC Girder with External Prestress Base on ABAQUS
Authors: Zhang Yu Xu
Published: October 2011

The reinforced RC girder with external prestress is applied more and more widely. Reinforcement of the girder is influenced by various factors, among which the concrete intensity degree and the prestress degree are mainly analyzed through the finite element software ABAQUS to learn their influence on the anti-bending bearing capacity of the externally reinforced RC simply supported beam. Since the reinforcement stresses of RC girder (regular reinforced concrete beam) are far less than the maximum intensity of the reinforcing steel bar, the concrete in the pulled area cracks, which causes the stiffness of constructional elements to decrease, deform and expand so that the elements become useless before it is damaged. External prestress can effectively improve such defect of the RC girder, and a great deal of research has been carried out. Due to the experimental boundedness and discreteness, large general finite element software ABAQUS is adopted to analyze the anti-bending bearing capacity of the externally reinforced RC girder, which is based on the size of experimental constructional elements in literature.
Application of Models-3/CMAQ on Asian Dust Storm
Authors: Wang Yi Bai , Fei Jian Fang , Huang Xiao Gang , Cheng Xiao Ping , Ge Yi Jun
Published: October 2011

A coupled modeling system has been developed to describe the mineral dust cycle in the atmosphere. It is composed of MM5, ECIP, WE (wind erosion model) and CMAQ. A strong dust storm of North China in 2002 is simulated by this system. The modeled results show good consistent with observations and pre-existing researches in aspects of dust emission flux in source regions, distributions , vertical profiles and time variation of dust aerosol. Therefore, it can be used for further study on Asian dust storms. Furthermore, this system can be developed for further studies of the impact of dust aerosols on air quality.
Environmental Sustainability of Microalgae Production as a Biofuel Source
Authors: Zhu Lian Dong , Naaranoja Marja , Hiltunen Erkki
Published: October 2011

The issues of energy shortage, global warming and climate change have led to an increased interest in new energy sector, such as microalgae-based biofuels. There are many advantages to produce microalgae as a biofuel feedstock, for instance, high photosynthesis efficiency and uncompetition with traditional agriculture on farmlands. Benefiting from current culturing technologies, such as open ponds and photobioreactors, commercial microalgae farming (e.g., Earthrise) is booming. In this regard, identifying the main environmental benefits associated with microalgae production is pretty important to support this promising industry. Although there are many researches on microalgae production, published information available on the sustainably environmental benefits is fragmented. The aims of this paper are to investigate and analyze environmental benefits related with microalgae biomass production for biofuel usage from sustainability perspective, systematically and explicitly, including water resource, land, nutrient, greenhouse gases and genetic modification dimensions.
Three-Dimensional Face Stability Analysis of EPBS Tunnels
Authors: Huang Xue Gang , Yang Yu You , Wang Gui He
Published: October 2011

A three-dimensional (3D) failure mechanism, based on the framework of the kinematical approach of limit analysis theory, is applied to calculate the face supporting pressure of a circular tunnel driven by the Earth Pressure Balance Shield (EPBS). The geometry of the mechanisms considered is composed of a sequence of truncated rigid cones. The numerical results obtained are presented.
Microstructure and Properties of WCP/Cu Layered Functionally Graded Materials Prepared by Vacuum Hot-Pressed Sintering
Authors: Guo Rong Xin , Yan Feng , Xia Hai Ting
Published: October 2011

The aim of this study is to fabricate WCp/Cu functionally graded materials (FGMs) and test its properties. Vacuum Hot-pressed Sintering technique is used to develop the graded WC particle reinforced Cu matrix composite. Using powder layering technique, a multi-layered WCp/Cu FGM have been prepared successfully. Scanning electron microscopy is used for microstructural analysis. Microscopic observations display that the microstructure of WCp/Cu FGM distribute gradually, and have no visible macroscopic interface. The mechanical properties of WCp/Cu functionally graded materials have been investigated, including Vickers's hardness, Young’s modulus and Tensile strength. Experimental results show that the properties of WCp/Cu FGM strongly depend on compositional variation.
Model Test Research on Bearing Behavior of Pile-Net Composite Foundation in Super Large Area and Deep Soft Soil
Authors: YU Jin Jiang , Cheng Qian Gong , Li Cheng Hui , Wu Jiu Jiang , Wen Hua
Published: October 2011

Based on the treatment of in-situ foundation, two distinct model tests for pile-net composite foundation in super large area and deep soft soil with different pile spacing were designed to study the bearing behavior of the piles. The result shows: the axial force of pile shaft increases with the growth of embankment filling load and gradually rises down along pile shaft to a certain depth, then slowly decreases afterwards. The velocity of force changing varies from the correlated soil layers, which indicates that pile shaft resistance appears to be unlike in different pile sites; The ratio of pile shaft resistance area to the overall pile length is relatively high while of normal resistance area is smaller ,and when the upper load is mainly supported by bearing course on pile end, pile-net composite foundation turns to be friction and end-bearing pile; For each level of loads, both pile-soil stress ratio and load shearing ratio of pile increase modestly, then tend to be steady till the next load level is applying on.
Seismic Response Characteristics of Deep Soft Site with Depth under Far-Field Ground Motion of Great Earthquake
Authors: Zhan Ji Yan , Chen Guo Xing , Jin Dan Dan
Published: October 2011

Considering the dynamic nonlinear characteristics of soil by equivalent linear method, one-dimensional wave models were established to study the seismic effects along depth of deep soft sites under far-field ground motions of great earthquake. The results show that the magnified effect of acceleration response spectrum of each layer present more outstanding under far-field ground motions than under Suzhou artificial waves, with the increasing of bedrock peak ground acceleration, there is probability that the peak of long-period component of acceleration response spectrum appears higher than that of the short-period within 15m depth, which may adversely affect the long-period building structures. However, the reduction coefficient of peak ground acceleration (PGA) along depth according to the three levels of earthquake fortification standard was relatively higher when inputting far-field ground motions of great earthquake. As the curve fitted by Longjun Xu et al. based on records collected California Strong Motion Instrumentation Program geotechnical arrays of the United States and Hosokura Mine arrays of Japan, is not suitable for Suzhou area, suited quantitative formula about reduction coefficient curve of PGA with depth in deep soft site is given. Besides, maximum shear strain at the depth of approximately 15m and 40m present to be greatly changed when inputting far-field ground motions of great earthquake, with the growth of inputting bedrock peak ground acceleration, the layer in the depth of about 15m comes to be the most unfavorable position of shear deformation.
Blast-Induced Cumulative Effects in Surrounding Rock of Largespan Tunnel under Multiple Blasts
Authors: Li Li Feng , Li Xi Bing , Ma Hai Peng , Xie Jiang Feng
Published: October 2011

The blasting vibration derived from multiple blasts and its effects on surrounding rock in a longspan tunnel will probably give rise to cumulative damage of surrounding rock, and weaken surrounding rock’s stability. Blastmate III, made by the Canadian company Instantel, is utilized to monitor the vibration signals from multiple blasts. Blasting vibration decay law and allowed safety distance of blasting are calculated by using Sadaovsk formula. Then, cumulative effects are analyzed by Hilbert-Huang Transform method as well as consequential instantaneous energy spectrum, and UTEP is presented to indicate the change of cumulative effects and damage in surrouding rock. The research shows that during the progress of damage evolution, “strengthening” and” deteriorating” may alternately appear several times. This is a zigzag reciprocating process in damage evolution of surrounding rock.
Investigation on Random Parameters of Aircraft Structural Reliability Model
Authors: Hu Jian Jun , Chen Yue Liang , Tan Xiao Ming , Bian Gui Xue , Xu Li
Published: October 2011

By studying on reliability model of aircraft structure holistic life assessment, several random parameters are chosen to analyze the randomness of aircraft structure life in this document, the sensitivity of random parameters is investigated to determine the important parameters. The fuzzy random parameters are also studied in this document, the influence of these parameters to aircraft structure reliability is analyzed in the final.
Sliding Mode Control with Adaptive Approaching Law for Bioreactor
Authors: Fan Li Ping , Song Ying , Zhang Jun
Published: October 2011

Bioprocesses have high nonlinearity and parameter uncertainty. In view of these specific natures of the bioreactor, system identification method was firstly used to linearize the nonlinear system and simplify the model of the biological reactor; then a new sliding mode controller with adaptive reaching law is designed for the reactor. The control method can not only analysis the sliding mode movement near or along the switching surface, but also design the dynamic process in trending segments of the system effectively, thus ensure good movement quality in the entire state space. Simulation results prove that the sliding mode control with adaptive reaching law can improve the control performance with negligible chattering and enhanced robustness.
Improved Extraction of the Local Carrier Generation Lifetime from Forward Diode Characteristics
Authors: Pengchan W. , Phetchakul Toempong , Poyai Amporn
Published: October 2011

This paper is proposed to extract the local carrier generation lifetime from forward current-voltage (I-V) characteristics of p-n junctions in case of non-uniform defects. The different geometry p-n junctions have been fabricated by a standard CMOS technology. The forward I-V and high frequency capacitance-voltage (C-V) characteristics of p-n junctions have been measured. The recombination current density can be extracted from the area forward current density by subtracting with the area diffusion current density. Form the recombination current density, the local generation and recombination lifetime can be obtained.
Preparation of the Three Main Layers of CdS/CdTe Thin Film Solar Cells Using a Single Vacuum System
Authors: Alamri Saleh N. , Benghanem M. S. , Joraid A. A.
Published: October 2011

This study investigates the preparation of the three main layers of a CdS/CdTe thin film solar cell using a single vacuum system. A Close Space Sublimation System was constructed to deposit CdS, CdTe and CdCl2 solar cell layers. Two hot plates were used to heat the source and the substrate. Three fused silica melting dishes were used as containers for the sources. The properties of the deposited CdS and CdTe films were determined via Atomic force microscopy, scanning electron microscopy, X-ray diffraction and optical transmission spectroscopy. An J-V characterization of the fabricated CdS/CdTe solar cells was performed under solar radiation. The short-circuit current density, Jsc, the open-circuit voltage, Voc, fill factor, FF and conversion efficiency, η, were measured and yielded values of 27 mA/cm2, 0.619 V, 58% and 9.8%, respectively.
Failure Analyses of Damaged Booster Pumps in a Power Plant
Authors: Alavi-Shoushtari Ali , Mousavi S. M. , Azimi-Yancheshmeh D.
Published: October 2011

the most common forms of damage mechanisms in water transportation pumps are cavitaion, erosion and corrosion. Type and intensity of failure mechanisms are affected by type of fluent, operation condition, and materials which are used in pump fabrication. Realizing the active mechanisms on failure of booster pump's inner surface was the aim of this investigation. In this study, scanning electron and optical microscopy and image analyses software were used to investigate morphology. Corrosion rate was measured by electrochemical test and water analyses. The results showed that cavitaion was the main mechanism of failure. In addition, scanning electron microscopy images and total hardness of feed water prove the erosion mechanism.
Study of Dye-Sensitized Solar Cells with Nanostructure Inn Compact Layer and Au Nano Particles
Authors: Chen Cheng Chiang , Chen Lung Chien , Kuo Shu Jung
Published: October 2011

This study examined the nanostructure InN compact layer and Au nano particles to dye-sensitized solar cells (DSSCs).We presents the DSSCs with Nitrided indium compact layer (InN-CPL) prepared by radiofrequency magnetron sputtering and doping Au particle in photoelectrode. The InN-CPL effectively reduces the back reaction in the interface between the indium tin oxide (ITO) transparent conductive film and the electrolyte in the DSSC. The Au particles effect conduction band of the TiO2 to rise open-circuit voltage to 0.7 v. The Au particles effectively rise inject electrons efficiency. For the DSSC without InN-CPL, the short-circuit current density and solar energy conversion efficiency are 15.6 mA/cm2 and 6.35 %, respectively. However, DSSCs with InN-CPL effectively rise short-circuit current density. The DSSC fabricated on 90 nm InN-CPL and doping Au particle showed the maximum power conversion efficiency of 8.9 % (AM1.5G) due to effective prevention of the electron transfer to electrolyte.
Density of States Extraction in Bulk Channel Area of a-Si:H Thin-Film Transistors by Using Low-Frequency Noise Analysis
Authors: Lee Kyunghwan , Son Younghwan , Lee Jaeho , Lee Jae Hong , Jang Seunghyun , Park Jung Jin , Kim Shinhyung , Shin Hyung Cheol
Published: October 2011

Density of states in the channel bulk area of a-Si:H thin-film transistors (TFTs) was extracted by using low-frequency noise analysis. The drain current noise power spectral density shows 1/ƒγ behavior at relatively high frequencies (ƒ > 1 kHz), which is due to the exponential distribution of tail states. For the analysis, the modified number fluctuation model which is correlated with mobility fluctuation was used. From the relationship (γ=1- kT/Et ) between exponent γ and the slope of exponential distribution Et of band tail states, the distribution of the band tail near conduction band was extracted.
Design and Simulation of Low-Power Multistage Amplifiers
Authors: Ren Ming Yuan
Published: October 2011

This paper presents a low-power multistage amplifier with a novel capacitor-multiplier frequency compensation (CMFC) technique. The proposed compensation strategy can allow the circuit to occupy less silicon area and to drive large capacitive loads more effectively. Moreover, smaller physical capacitance results in higher gain-bandwidth product (GBW) and improved transient responses. Furthermore, the capacitor multiplier stage (CMS) embedded in CMFC creates a left-half plane (LHP) zero, which boosts the phase margin and enhances the stability of the amplifier. Implemented in a commercial 0.5-μm CMOS technology and driving 500pF capacitive load, a three-stage CMFC amplifier achieves over 120dB gain, 1.699MHz GBW and 1.625V/μS average slew rate, while only dissipating 330μW under 3.3V supply.
Equilibrium and Thermodynamics of Adsorption of Fe/Ac for Aniline from Dilute Solutions
Authors: Li Bing Zheng , Guo Ya Bing , Liu Lai Shuan , Xue Yong Bing , Sun De Kui
Published: October 2011

The effect of iron doping on physical and chemical properties of activated carbon, the effect of initial concentration and temperature on adsorption behavior of adsorbents for aniline from water, and adsorption equilibrium and thermodynamics were investigated. The results show that Fe doping obviously increase acidic oxygen-containg groups of activated carbon surface. Effect of Fe doping on adsorption capacity of aniline at the low concentration is insignificant. Equilibrium adsorption uptake decreases with an increase in adsorption temperaure. Freundlich model can better describe adsorption behavior of aniline on AC and Fe/AC. Aniline adsorption is spontaneous and exothermic.
Chloride Penetration through Cracks in Concrete with Various Mixing Properties
Authors: Yoon In Seok
Published: October 2011

The purpose of this study is to identify and quantify the effect of the mixing features of concrete such as size of coarse aggregate, high strength and steel fiber reinforcement on chloride penetration through micro-cracks. In examining the effect of size of coarse aggregate on chloride penetration through cracks, the cracks should not impact on chloride penetration directly, although small size of coarse aggregate can lead to complicated micro-cracks in concrete. On the contrary, chloride should easily penetrate through micro-cracks concentrated at the surface of coarse aggregates. In examining the effect of high strength concrete on chloride penetration through cracks, high strength concrete has an excellent performance to resist with chloride penetration. If cracks are generated in high strength concrete, however, its performance is reduced up to the level of ordinary concrete.
Growth of Vertically Aligned ZnO Nanowires on Iron Oxide Layer
Authors: Pung Swee Yong , Choy Kwang Leong
Published: October 2011

A low cost and substrate-independent method has been established to synthesize vertically aligned ZnO nanowires (NWs) on iron oxide films coated silicon substrates via low pressure Chemical Vapor Deposition (CVD) method at 650oC. In this study, Si substrates were dipped into the iron (III) nitrate nonahydrate solution prior to the synthesis process. This oxidized iron film facilitated the growth of highly oriented (002) ZnO seed layer, which allowed subsequent vertically aligned ZnO NWs to be grown on top of it during the synthesis. This approach has provided a good alternative to grow vertically aligned ZnO NWs without the need of considering the epilayer relationship between the ZnO and the material to be used as substrate.
Study on the Water Proof Seal for Underwater Robot Using MR Fluid
Authors: Yun Dong Won , Jinho Kyung , Kim Soo Hyun
Published: October 2011

Water proofing is an obvious problem in developing successful underwater robots. In previous research, most underwater robots have used a mechanical seal for water proofing. However, this kind of seal has not proved reliable because of friction and wear between the stationary parts and moving parts. This paper presents a method to seal the moving parts in underwater robots, especially robot fish. The proposed seal for under water robots is developed using Magneto Rheology (MR) fluid. MR fluid is a kind of smart material, of which the viscosity varies with the external magnetic field. This fluid is composed of silicon oil and small magnetic particles, which are micrometer sized, and when an external magnetic field is applied to the fluid, the small particles align with the magnetic flux line. The arrays of magnetic particles in the fluid inhibit the fluid flow, which changes the viscosity of fluid. Taking advantage of this phenomenon, we devised a seal with a permanent magnet and MR fluid. Our analysis demonstrates the performance of the developed seal. The magnetic equivalent circuit method and FEM (Finite Element Method) are used to calculate the magnetic field and the analysis results show that the developed seal can sustain 10 atm pressure.
On the Analysis and Design of Steel Structure to Mitigate Progressive Collapse
Authors: Mirtahery M. , Abbasi Zoghi M.
Published: October 2011

Since Ronan Point tower local collapse in UK in 1968, progressive collapse phenomenon in structures attracted more attention for civil engineers all over the world so there were no useful researches and manual codes related to progressive collapse designing before. Progressive collapse occurs when loading pattern, boundary condition and resisting path changed, so critical elements undergo excessive unpredicted loading. We cannot omit reason of collapse as well as prevention of distribution of it that cause progressive collapse. Also, we cannot predict exact location of collapse beginning, so we should generalized design guides to whole or part of structures elements based on risk analyzing. Also we can use load carrying element removal scenario for critical elements. To prevent progressive collapse, structural systems require to having a well-distributed, redundant lateral load resisting system and ductile connections capable of undergoing large inelastic rotations without failing. There are some new guides and criteria for elements and connections to be designed to resist progressive collapse. Depends on required accuracy, importance of the buildings and acceptable risk level, the analysis methodologies ranged from linear to nonlinear with static and dynamic approaches. In this paper, codes and researches recommendations to resist progressive collapse for steel structures are presented, classified and compared. Also, applicable design methods based on codes and some retrofitting methods are summarized.
Analytical Solutions for Moving Elliptical Paraboloid Heat Source in Semi-Infinite Plate
Authors: Ghosh Aniruddha
Published: October 2011

An attempt has been made in this paper to findout the trainsent temperature distribution on the welded plates through analytical as well as numerical method considering double elliptic paraboloid moving heat source volume.It has been assumed that heat is distributed through gaussian manner on the welded plates and modes of heat transfer for welded plates are conduction as well as convection.With the help of these solutions dimnesions of weld bead geometry,HAZ width and thermal stress have been predicted and validated with the experimental data.
Isochronal and Isothermal Annealing of Wrought Aluminum Alloy
Authors: Abdel-Rahman M.A. , Kamel N.A. , Refeay Abdullah A. , Lotfy Yahia A. , Badawi Emad A.
Published: October 2011

Positron annihilation lifetime (PAL) is one of the most important nuclear techniques used in material science. Electrical measurements are also used in material science. Samples of 25 % deformation have been used for these studies. Both positron annihilation lifetime and electrical measurements were used to determined the activation energy of migration the dislocation in 7075 alloy. The isothermal annealing measurements were performed at 643, 663, 683 and 703 K. The activation energy of migration the dislocation are obtained as 1.35 ± 0.16 eV and 1.25 ± 0.05 eV for positron annihilation lifetime and electrical techniques respectively.