• Volume 30,Issue 4,2008 Table of Contents
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    • Building Energy Efficiency Design Procedure Based on Digital Technology

      2008, 30(4):1-5. DOI: 10.11835/j.issn.1674-4764.2008.04.001

      Abstract (600) HTML (0) PDF 4.08 M (515) Comment (0) Favorites

      Abstract:Abstract:Digital design technology is crucial for building energy efficiency design, while the key of building energy efficiency design is to analyze the entire design process, dynamic balance and energy cost. Through the application of digital technology in architectural design during its earlier phases, we can analyze such factors as local climate and terrain, create a "virtual building", simulate its actual condition, and conduct a scientific quantitative analysis of the key problems in architectural design. These actions will optimize the proposed design in a timely manner and achieve energy efficient design under the guidance of scientific analysis. Meanwhile, by exploring energy efficiency design procedure based on digital technology, we can adapt to a higher standard of energy efficient design in our new times.

    • Reducing the Heating and Cooling Energy Consumption of Buildings

      2008, 30(4):6-9. DOI: 10.11835/j.issn.1674-4764.2008.04.002

      Abstract (873) HTML (0) PDF 2.46 M (1180) Comment (0) Favorites

      Abstract:Abstract:This research aims at proposing measures to enhance the energy efficiency of buildings in the city of Guiyang. A computer simulation study was conducted on the basis of a building model using the DeST software package. The indoor temperature and yearround heating and cooling loads were simulated. From analysis of the simulation results and taking into account the climate of Guiyang, three measures for energy efficient buildings in Guiyang are proposed. 1) Heating is a greater priority than cooling in comfortable airconditioning system design; 2) Natural ventilation should be given priority in cooling design and adjustment during seasonal transition is important to reducing energy consumption in building cooling; 3) Insulating the building envelope and lowering the glazing ratio of walls are critical for reducing energy consumption in heating buildings. Our conclusions will be useful for guiding energy efficient building design not only in Guiyang but also in mild climatic areas of P. R. China.

    • Using an Oprobit Model for Empirical Research Concerning the Determinants of the Land Transfer Behavior of Farmers

      2008, 30(4):10-14. DOI: 10.11835/j.issn.1674-4764.2008.04.003

      Abstract (628) HTML (0) PDF 1.05 M (2) Comment (0) Favorites

      Abstract:This paper begins with a brief introduction to the research status of factors influencing farmers’ land transfer behavior. A model for studying such behavior was set up using an ordered probitOprobit) regressive method. Data from field questionnaires completed by 142 farmers in two counties in Jiangsu Province, P. R. China, show that the land transfer behavior of farmers is related greatly to their family security level, the number of farm laborers, the number of nonfarm laborers, the value of agricultural assets, the number of years of they have held their land, and other factors. We conclude with suggestions to promote the transfer of farmers’ land.

    • The Maximum Spectral Luminous Efficiency of Mesopic Level

      2008, 30(4):15-18. DOI: 10.11835/j.issn.1674-4764.2008.04.004

      Abstract (599) HTML (0) PDF 1013.62 K (2) Comment (0) Favorites

      Abstract:To obtain the expression of maximum spectral luminous efficiency of mesopic level, we studied the contribution to spectral sensitivity in the mesopic region of the rods and cones based on heterochromatic brightness matching and reaction time, respectively. We next acquitted the expression of maximum spectral luminous efficiency of the mesopic level. Our opinion is that the results based on different experiments reflect different vision characteristics of human beings. The expression of maximum spectral luminous efficiency should be chosen in accordance with the application. We advise that the maximum spectral luminous efficiency based on heterochromatic brightness matching should be chosen in evaluating the effect of night scene lighting. The maximum spectral luminous efficiency based on reaction time should be chosen in designing road lighting.

    • A Visibility Designing Method Based on Luminance Uniformity

      2008, 30(4):19-22. DOI: 10.11835/j.issn.1674-4764.2008.04.005

      Abstract (1118) HTML (0) PDF 2.09 M (8) Comment (0) Favorites

      Abstract:To determine the influence of luminance uniformity on visibility levels, and to study methods of visibility design, we carried out experiments having different luminaire collocation modes. Cutoff luminaire and semicutoff luminaire were used in these experiments. The relationship of luminance uniformity and visibility level distribution of targets was studied based on small target visibility calculation methods. The results indicate that if luminance uniformity is good, the road luminance distribution should remain uniform, then the visibility levels of all targets are positive or negative). If luminance uniformity is insufficient, it can be reduced intentionally and the visibility level of each target can be increased. A higher STV value can be gained for the entire road. The method of limiting road visibility level distribution should be established in road lighting design.

    • Thinking of the Architectural Language and Concept

      2008, 30(4):23-26. DOI: 10.11835/j.issn.1674-4764.2008.04.006

      Abstract (644) HTML (0) PDF 994.72 K (1) Comment (0) Favorites

      Abstract:There is difference and relationship among the concepts of architectural language, architectural image and architectural conception. Understanding their connotations and extensions is important for revealing the aesthetic theme of architecture and understanding the purpose of the architectural creation. By analyzing ancient scholar Wang Bi’s “Zhou Yi Lue LiMing Xiang”, I illustrate the dialectical relations among these concepts: architectural language is the material means of architectural image creation, architectural image is the media of architectural conception, and architectural conception is the aesthetic theme of architectural creation. In what I have written here, I try to provide a new and rational thinking pattern for architects.

    • Ecothinking Model of Modern Landscape Design PhilosophiesIllustrated with a Case Study of South Entrance of Tongniuling in Dalian

      2008, 30(4):27-32. DOI: 10.11835/j.issn.1674-4764.2008.04.007

      Abstract (914) HTML (0) PDF 3.35 M (5) Comment (0) Favorites

      Abstract:We discussed the trends and challenges of rapid urbanization for modern landscape from a development viewpoint. We analyzed the problems of modern landscape in P. R. China. Based on ecological principles, we proposed a corresponding eco-thinking model composing eco-thinking of vision, culture, environmental protection and public participation. We carried out a case study of the south entrance of Tongniuling Scenic Spot in Dalian. We constructed diverse scenarios according to the leading factors selected by factor analysis. We assessed them with the Delphi method and public anticipation. The priority rating was, in order, scenario number 2 (48.3%), number 1 (30.5%) and number 3 (15.7%). Scenario number 2 was the best for its prominent visual image, typical culture presentation, weaker disturbance and reasonable cost. Scenario numbers 1 and 3 took culture and environment as leading factors, respectively. The cost of the former was low while the latter was high. Our work indicates that the eco-thinking model, as a brand-new thinking for modern landscape, is feasible.

    • A Community Development Approach to the Conservation and Improvement of Historic Conservation Areas

      2008, 30(4):33-37. DOI: 10.11835/j.issn.1674-4764.2008.04.008

      Abstract (634) HTML (0) PDF 1.02 M (4) Comment (0) Favorites

      Abstract:In this paper, we introduce the concept and notion of community development. We analyze the nature and character of Chinese historic conservation areas. We recommend using a community development approach in historic conservation area to transform historic conservation plans of physical environments into comprehensive community development plans. We encourage and promote the organized participation of community inhabitants in such plans and in the implementation of joint conservation and improvement tasks with the government for historic conservation areas.

    • City Residence in the View of Regional Culture: Protection and Renovationof Humanism in Luoyang Cross Street

      2008, 30(4):38-42. DOI: 10.11835/j.issn.1674-4764.2008.04.009

      Abstract (825) HTML (0) PDF 1.97 M (10) Comment (0) Favorites

      Abstract:Problems of cultural environmental protection are acute during the reconstruction of some historic cultural cities. In order to understand the regional cultural features of the old cross street of Luoyang in P. R. China, we analyze the principle of humanistic protection of the street. Based on this understanding, we put forward principles and methods for protection and renovation. We also studied creative ways to protect the historical culture block at present and in the future.

    • The Relationship between Land Scale for Constructionand Social Economic Development

      2008, 30(4):43-47. DOI: 10.11835/j.issn.1674-4764.2008.04.010

      Abstract (458) HTML (0) PDF 1.88 M (1) Comment (0) Favorites

      Abstract:I studied land use under the macroscopic background of rapid urbanization in P. R. China. Currently, there are many problems in land use which restrict the urbanization development. Therefore, I hope to discover existing problems, find out the dynamic law of land use, analyze the affecting factors, and probe into the counter-measures and ways to prohibit the shortterm use and blind development in land use in the urbanization process. I analyze the relationship between construction land, macroeconomic indicators and social development. I mainly analyze data about construction land, GDP, fixed assets, industry, real estate, traffic, and more. I conclude by pointing out their interrelationships.

    • A Comparative Study of European and American PublicHousing Policies and Its Findings

      2008, 30(4):48-52. DOI: 10.11835/j.issn.1674-4764.2008.04.011

      Abstract (779) HTML (0) PDF 1.01 M (12) Comment (0) Favorites

      Abstract:I studied the similarities and differences of public housing policy between European countries and the United States using historic and comparative methods. Public housing policy was put in place in postwar European countries and the U.S. Differences in the policies of these countries were that the European policy intervened in the housing market directly and thoroughly but the American policy intervened in the housing market indirectly by financial and revenue means. The key finding is that housing in P. R. China is an important part of the people's livelihood and the government should not completely pass responsibility for providing it to the market. China should set up its own public housing policy and change the mode of land supply and housing manufacturing. China also should adopt multiplicative means, including direct government investment and encouraging the social anticipation and planning adjustment to guarantee the housing rights of middle-and-low-income households.

    • Ecological Planning Based on Landscape Ecology: A Case Study of Lianyungang City

      2008, 30(4):53-57. DOI: 10.11835/j.issn.1674-4764.2008.04.012

      Abstract (600) HTML (0) PDF 31.75 M (7) Comment (0) Favorites

      Abstract:Landscape ecological planning here is addressed to the issues of landscape patterns, landscape ecological process and interactions between human activities and landscapes. Building on existing landscape ecology and ecological planning methods, we developed a method for landscape ecological planning by applying Ecological Service Value (ESV) and Landscape Fragmentation (LF) analysis. Using classified Landsat TM (May 20, 2006) images, we quantified the regional ESV and LF for Lianyungang City. A spatial differentiation map of ESV and LF overlays was used to create a map of landscape ecological planning. Scenarios for landscape ecological planning were represented in 4 major functional zones for Lianyungang City, including optimized, emphasized, restricted and forbidden development zones.

    • Preliminary Optimization of Partial Singlelayer Reticulated Shells Based on Uniform Design[JP]

      2008, 30(4):58-63. DOI: 10.11835/j.issn.1674-4764.2008.04.013

      Abstract (686) HTML (0) PDF 27.22 M (583) Comment (0) Favorites

      Abstract:Size, shape and topology optimizations are involved in the structural design of partial singlelayer reticulated shells. To meet the requirements of computation efficiency during preliminary design, a uniform design method was adopted to achieve multilevel optimization. Only existing software packages for reticulated shells were used in the experiment design. By regressing the computing data, approximate functional relations between the indexes (steel weight, deflections, basic frequency, and minimal nonlinear buckling load) and variables (rise of the shell, singlelayer area, and design stress ratio for singlelayer members) were obtained. The best combination of the variables was acquired by solving a simple programming problem. Comparative design of a multipointsupported hexagonal reticulated shell verified the efficiency and reliability of this approach.

    • Synthesis Mode of Stress and Strain for Complexus Theory of Geomaterials Damage

      2008, 30(4):64-67. DOI: 10.11835/j.issn.1674-4764.2008.04.014

      Abstract (618) HTML (0) PDF 1.01 M (1132) Comment (0) Favorites

      Abstract:Although the constitutive model for geomaterial damage has developed significantly, there is still dispute regarding the synthesis mode of stress and strain for the complexus theory of geomaterials damage. The synthesis mode of stress and strain for the complexus theory of geomaterials damage was studied in depth in light of the basic concepts of continuum mechanics. A general synthesis mode of stress and strain for the complexus theory of geomaterials damagmall. The amount of sampling could sharply decrease by using the dual sampling method. During the comparison, the supporting role exaggeration of the line element, which is used in the FEM model to simulate the initial lining and rock bolt, was found by FEM simulation. The lining element reaction forces which were greater than usual were reported in FEM analysis results. Deeply Buried Tunnel Reliability Analysis was developed on the platform of ANSYS.

    • Settlement Analysis of a Laboratory Model Test of Dewatering of a Metro Station in Shanghai

      2008, 30(4):68-72. DOI: 10.11835/j.issn.1674-4764.2008.04.015

      Abstract (548) HTML (0) PDF 2.02 M (729) Comment (0) Favorites

      Abstract:With the exploitation of urban underground spaces, deep foundation pit constructions increasingly are evaluated. Pits in soft soil areas adjacent to operating subway are especially difficult to excavate. After indoor testing of water drainage for a station on the Shanghai Metro line 9, and on the basis of treatment and analysis of water level drain hole and flux monitoring data, pore water pressure, layered settlement and surface soil settlement, we summarize the relationship between factors influencing settlement during water drainage. This research offers design experience and blueprints for water drainage and ensures the safety of metro pit construction and enclosure structure stability.

    • Pile Foundation Analysis Using a Boundary Element Method

      2008, 30(4):73-77. DOI: 10.11835/j.issn.1674-4764.2008.04.016

      Abstract (721) HTML (0) PDF 1.20 M (914) Comment (0) Favorites

      Abstract:Taking the extended Mindlin solution of a vertical point load acting in the interior of a multilayered elastic medium as the basic solution, an indirect boundary element method (BEM) was adopted to analyze pile foundations embedded in a multilayered elastic soil. The numerical analysis was carried out by the compiled program for a pile foundation in an homogeneous soil and a pile foundation in a multilayered soil. Reasonably good agreement is obtained between the present and existing solutions. Compared with the FEM software ABAQUS, the computational speed of BEM is much faster than that of FEM. Applying BEM in practice is convenient. It is pointed out that the exact measurement of elastic modulus is the key factor for applying BEM in geotechnical engineering.

    • Reliability Analysis of Initial Support in a Highway Tunnel Based on the Monte Carlo Method 

      2008, 30(4):78-81. DOI: 10.11835/j.issn.1674-4764.2008.04.017

      Abstract (561) HTML (0) PDF 1.04 M (824) Comment (0) Favorites

      Abstract:The Monte Carlo Finite Element Method is superior to other methods when it is used to analyze the reliability of the initial support of a highway tunnel. A correct reliability index could be collected when an adequate number of samples is selected because the failure probabilities of engineering structures are usually very small. The amount of sampling could sharply decrease by using the dual sampling method. During the comparison, the supporting role exaggeration of the line element, which is used in the FEM model to simulate the initial lining and rock bolt, was found by FEM simulation. The lining element reaction forces which were greater than usual were reported in FEM analysis results. Deeply Buried Tunnel Reliability Analysis was developed on the platform of ANSYS.

    • The Application of Gene Expression Programming in Concrete Creep Analysis

      2008, 30(4):82-86. DOI: 10.11835/j.issn.1674-4764.2008.04.018

      Abstract (629) HTML (0) PDF 1.23 M (890) Comment (0) Favorites

      Abstract:The creep analysis of concrete is of great importance in stress calculation and deformation analysis of concrete structures. Since many factors affect concrete creep, the creep function is highly nonlinear, making it difficult to obtain satisfactory results using the traditional regression method. The gene expression programming (GEP) method, which combines the advantages of GA and gene programming, shows great promise and capability of data mining in nonlinear fitting. Based on theoretical analysis of GEP, the data mining model of the creep function was established by using GEP. Examples indicate this model is more accurate than functions obtained by conventional methods.

    • A Calculating Method of NonLinear Earth Pressure Behind Retaining Walls

      2008, 30(4):87-90. DOI: 10.11835/j.issn.1674-4764.2008.04.019

      Abstract (624) HTML (0) PDF 1.04 M (1174) Comment (0) Favorites

      Abstract:Based on equilibrium analysis of forces and moment with inclined soil element, an analytical solution of earth pressure with inclined surface of fill and rough retaining wall was proposed, and the influence of slope angle of fill on earth pressure also was discussed. It is shown that the classical Rankine's earth pressure theory is a special case of the analytical solution with horizontal surface of fill and a smooth retaining wall. The results also show that the limiting rupture angle of a slidingwedge behind a retaining wall decreased with increasing slope angle of fill or friction angle between soil and a retaining wall, with the settled value of the internal friction angle of fill. The nonlinear character of earth pressure exhibited distinctly for the earth pressure along a retaining wall was obtained by an analytical solution. The value of earth pressure is 0 at the toe of retaining wall, consistent with the testing results. In addition, the value of earth pressure at the toe of the retaining wall will increase rapidly with increasing slope angle of fill. The analytical solution of earth pressure behind a retaining wall with fill of clay soils can be further studied with the investigative method we developed.

    • A Transfer Precision Study of Interior Horizontal Coordinates of Oblique Super HighRise Buildings

      2008, 30(4):91-95. DOI: 10.11835/j.issn.1674-4764.2008.04.020

      Abstract (518) HTML (0) PDF 1.48 M (1202) Comment (0) Favorites

      Abstract:When staking out super highrise building construction, it is important to analyze the horizontal coordinate precision of the control point of the axis. For coordinate transfer of control points of oblique super highrise buildings with high accuracy and precision, methods combining the electronic tachometer with laser aligner were adopted. The measurement sections were transited by sections many times on the floors. The coordinates of control points of lower floors gradually were transferred to the top floor by relays. We then could use the electronic tachometer to measure the linear distance between the control points of each floor and the control point of the axis, calculate the coordinates of the axis control point, and analyze the precision of the coordinates. Thus, integrated methods of transferring horizontal coordinates of super highrise buildings setting out of axis repeatedly can be taken from the control points to the monitoring points section by section. The precision integrated methods improve the coordinates of the control point of the axis by adopting advanced measurement equipment. We recommend choosing an electronic tachometer with different precision and a laser aligner to analyze the control point error quickly and accurately, provide a complete and systematic method for optimizing the stakingout scheme in construction, and guide the stakingout work and deformation monitoring work of super highrise buildings or oblique super highrise building construction.

    • Stability of Particlesize Improved Roadbed in Permafrost

      2008, 30(4):96-98. DOI: 10.11835/j.issn.1674-4764.2008.04.021

      Abstract (690) HTML (0) PDF 1010.57 K (826) Comment (0) Favorites

      Abstract:Roadbed stability, including thermal and strength stability, is the ability of roadbed to adapt to pavement settlement, slurry effusion, shear slide and haunching up of the roadbed resulting from moving vehicles and many natural influences. Thermal stability is the sensitivity of the thermal state of the roadbed to the external environmental condition. It is the key point of the roadbed stability in permafrost. Research concerning roadbed thermal stability in permafrost is analyzed, and the judgment principle of thermal stability is discussed. The regular change of the ground temperature and deformation of particlesize improved roadbeds are analyzed by studying field observation data of the particlesize improved roadbed after two freezing and thawing cycles. We conclude that the particlesize improved roadbed can raise the upper limit of frozen soil. Based on the judgment principle, the particlesize improved roadbed is regarded as a new type of stable structure.

    • A Numerical Simulation of Coalbed Methane Desorption and Diffusion Enhanced by Ultrasound Heating

      2008, 30(4):99-104. DOI: 10.11835/j.issn.1674-4764.2008.04.022

      Abstract (531) HTML (0) PDF 1.12 M (949) Comment (0) Favorites

      Abstract:We discuss the development of coal bed microstructure and the mechanism of enhancing the desorption/diffusion of coalbed methane by ultrasound. We present a mathematical model to describe the desorption/diffusion process of coalbed methane due to the ultrasound heating effect. Two cases of gas release with or without ultrasound fields in coal samples were simulated. We found that the temperature and the micropore diffusion coefficient of the system were improved by ultrasound transferred heat energy, while the dynamic fraction of free gas in pores was enhanced and the dynamic fraction of adsorbed gas was weakened.

    • Mechanical Behaviors of LargeSpan Space Structures in the Construction Process

      2008, 30(4):105-108. DOI: 10.11835/j.issn.1674-4764.2008.04.023

      Abstract (639) HTML (0) PDF 2.59 M (12) Comment (0) Favorites

      Abstract:Traditional structural design emphasizes checking whether a loaded structure satisfies design requirements without considering the construction process. There is a great difference in structures between the states in construction processes and design, however. To solve the above problems, a method of nonlinear timevarying mechanics was adopted to analyze the construction process of a structure. The structural characteristics in each construction stage were analyzed by timevarying mechanics and the variations of internal force and displacements obtained. We conclude that designs will not be safe if the time varying effect in the construction process analysis is not considered. We offer advice on the design and construction of largespan structures.

    • Study on Vibration Performance of Engineered Wood Truss Joist Floors

      2008, 30(4):109-113. DOI: 10.11835/j.issn.1674-4764.2008.04.024

      Abstract (781) HTML (0) PDF 1.10 M (1) Comment (0) Favorites

      Abstract:In recent years wood trusses are widely used in buildings due to their excellent performance and ease of construction. As with solid lumber joists, however, the vibration of wood truss joist floors can cause occupants to feel discomfort. To understand the relationship between the vibration performance of wood truss joist floors and the perceptions of occupants, experimental and subjective evaluations were conducted on six truss joist floors. The results show there is close relationship between perceptions of occupants and the fundamental natural frequency, static deflection and vibration acceleration of truss joist floors. The installation of bracings and straps greatly improved the vibration performance of light truss joist floors. We suggest that two or more factors should be included in the design criteria for controlling wood floor vibration, such as static deflection and fundamental natural frequency. Peak acceleration can be adopted as a factor in the evaluation system of vibration performance of wood truss joist floors.

    • An Attribute Mathematical Model and Its Application in Predicting and Classifying Rockbursts

      2008, 30(4):114-120. DOI: 10.11835/j.issn.1674-4764.2008.04.025

      Abstract (611) HTML (0) PDF 1.10 M (4) Comment (0) Favorites

      Abstract:Based on attribute mathematical theory, an attribute recognition model to predict and classify rockbursts was established. Firstly, the main factors of rockburst, such as the maximum tangential stress of cavern walls σθ, uniaxial compressive strength σc, uniaxial tensile strength σt, and the elastic energy index of rockWet, were chosen for the analysis; and three factors, includingσθ/σc,σc/σt andWet, were chosen as the criterion indices for rockburst prediction in the proposed model. Secondly, attribute measurement functions were constructed to compute the attribute measurement of a single index. Thirdly, the index weight was determined by similar weights defined by similar figures. Finally, the possibility and classification of rockburst were recognized by the confidence criterion. A series of underground rock projects were assessed with the proposed model and method to verify the proposed model. The study indicates that the synthetic assessment results agree well with the practical records, and are coherent to those of the fuzzy synthetic evaluation model and the matter-elements model. Moreover, the proposed model was used to predict rockbursts of a hydropower station and Qinling Tunnel. The results are coherent to those of the synthetic evaluation method, such as artificial neural network and distance discriminant analysis method, and others. The research indicates that an attribute recognition model can predict and classify rockbursts in engineering projects deep underground and provides a new method in practice.

    • A Stress Path Damage Constitutive Model for Sang

      2008, 30(4):121-124. DOI: 10.11835/j.issn.1674-4764.2008.04.026

      Abstract (822) HTML (0) PDF 1.06 M (2) Comment (0) Favorites

      Abstract:A hypothesis that the skeleton deformation of sand is only the deformation of the interfaces of grains, and the deformation characteristics including nonlinearity, plastic deformation and shear dilation are controlled by the sliding of interfaces of grains within skeleton, is presented.The contact between grains is classified as perfect contact and sliding contact in this paper.In the elastic deformation phase, the contact between grains is regarded as perfect contact.With the increase of shear stress, there are gradual conversions from perfect contacts to sliding contacts which are viewed of damages in this paper.Based on MohrCoulomb law, a calculation method for the damage ratio is given according to the relative distance of the stress point to the initial damage line and failure line.On this basis, a damage constitutive model is proposed.The model properties can be conveniently obtained through conventional triaxial compression test and constant stress ratio consolidation test.Test results indicate that the model is capable of predicting deformation behavior for various conditions, including varying consolidation conditions and stress paths.

    • Correlation of Algae Growth with Nitrogen and Phosphorus Concentrations at the Mouth of the Jialing River

      2008, 30(4):125-128. DOI: 10.11835/j.issn.1674-4764.2008.04.027

      Abstract (610) HTML (0) PDF 1.00 M (9) Comment (0) Favorites

      Abstract:Correlation analysis was used to evaluate the influencing factors and relationship of algae growth and nitrogen and phosphorus concentration in order to determine the algae growth change rule at the mouth of the Jialing River in Chongqing, P. R. China. The results indicate that algae grows rapidly during June and July. Under the same climate conditions and small differences of nutrient concentration, there is a negative correlation between algae cell density and flow velocity. Areas having tranquil water flows are advantageous for algae multiplication. Algae cell density has a positive linear relationship to nitrogen and phosphorus concentrations. Phosphorus has a greater influence weight than nitrogen, however, indicating that phosphorus is the restrictive factor for algae growth.Phosphorus affects algae growth more strongly in areas with tranquil water flows where the algae is more active. Fast flow velocity, abundant sediment content, low water temperature, and other factorss will affect the correlation of algae growth with nitrogen and phosphorus concentrations. This correlation is not obvious during rising flood stages. The results provide important parameters for understanding the changing water quality patterns of the Jialing River and the conditions and mechanism analysis of water eutrophication.

    • Influence of Shock Loading on the Operating Performance of an Anaerobic Baffled Reactor

      2008, 30(4):129-131. DOI: 10.11835/j.issn.1674-4764.2008.04.028

      Abstract (699) HTML (0) PDF 1.36 M (2) Comment (0) Favorites

      Abstract:Wastewater from a slaughtering house was treated by an anaerobic baffle reactor (ABR). The effects of variable loads on the operating performance of the ABR were studied. The results show that the ABR was very stable with respect to shock loading due to its special structure. The change in COD removal efficiency was less than 5% when the influent COD concentration was kept between 2 500~3 000 mg/L and the HRT decreased from 27.5h to15h. When HRT was kept for 20h and the influent COD concentration increased from 2 500 mg/L to 4 800 mg/L, COD removal efficiency only decreased by 69% the second day after the load change.

    • Research on Preparation of Non-Autoclaved Aerated Concrete with Phosphorus Slag

      2008, 30(4):132-135. DOI: 10.11835/j.issn.1674-4764.2008.04.029

      Abstract (508) HTML (0) PDF 1.01 M (11) Comment (0) Favorites

      Abstract:In order to prepare aerated concrete with alkali-phosphorus slag and better use of industrial waste, the powder composition of the slurry was investigated. The impacts of certain factors on aerated concrete, including the foaming agent, sodium silicate modulus, alkali content and the temperature of alkali solution also were investigated using single-factor test methods. The results indicate that: the cement and fly ash in powder have impacts on the pouring stability of slurry, and the bulk density of aerated concrete is impacted by the amount of foaming agent, sodium silicate modulus and alkali content. In the experiment, aerated concrete with bulk density in range of 535~887 kg/m3 and compressive strength of 6~9.5 MPa was produced; its mechanical performance conforms to the requirements of the standard GB 119682006.

    • Properties of Steel Fiber Asphalt Concrete and Its Application

      2008, 30(4):136-140. DOI: 10.11835/j.issn.1674-4764.2008.04.030

      Abstract (613) HTML (0) PDF 1.18 M (0) Comment (0) Favorites

      Abstract:To prevent asphalt pavement from cracking under low temperatures and prolong its fatigue life, we tested the properties of a new type of steel fiber asphalt pavement. The tests evaluated Marshall stability, dynamic ruts, and cleavage strength under both low and normal temperature conditions. We also analyzed the anti-corrosion property of steel fiber and the factors affecting the properties of the steel fiber asphalt mixture. The steel fiber asphalt pavement was installed on a highway in Chongqing, P. R. China to investigate the construction art of the steel fiber asphalt mixture and examine its effect in field use. The test results and concrete use in the field show that the cleavage strength and flexibility of steel fiber asphalt concrete increase due to the action of steel fiber. We conclude that the anti-cracking capacity of asphalt pavement under low temperature conditions can be improved by steel fiber. The construction art of steel fiber asphalt pavement is the same as common asphalt pavement without the necessity of anti-corrosion processing for steel fiber. The research results are useful for pavement material selection in low temperature regions and heavy traffic road pavement designs.

    • Advances in the Study of Nitrogen and Phosphorus Removal Mechanisms in Constructed Wetlands

      2008, 30(4):141-146. DOI: 10.11835/j.issn.1674-4764.2008.04.031

      Abstract (815) HTML (0) PDF 1.05 M (21) Comment (0) Favorites

      Abstract:Constructed wetlands are wastewater treatment ecosystems composed of substrata, plants, microorganisms and water. We summarize herein recent research findings about nitrogen and phosphorus removal mechanisms in wastewater treated by constructed wetlands and the influencing factors, such as substrata, plants, microorganisms, hydraulic loads, temperature and dissolved oxygen. To increase the nitrogen and phosphorus removal efficiency and extend the fields of constructed wetland application, nitrogen and phosphorus removal mechanisms, influencing factors and techniques must be studied intensively in the future.

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