Resource-based cities (RBC): a road to sustainability

Resource-based cities (RBC) have made momentous contributions to urbanization in China. However, as natural resources are exhausted, RBC are facing an enormous challenge. In this paper we put forward a resource-based city sustainability index (RCSI) and a resource-based city coordination index (RCCI), including environmental, social, and economic dimensions, adopted three weight scenarios, and selected 13 cities for study. The results: (a) help locate the problems by analyzing both dimensions and indicators; (b) simulate the trends of how RBC emerged, grew, declined, and regenerated; (c) categorize RBC into four types by integrating RCSI and RCCI; (d) give policy makers a holistic and comprehensive perspective in the future urban regulation and management; and (e) highlight a road to sustainability.     

Institutions,policies and soil degradation: theoretical examinations and case studies in Southeast China

Abstract

Southeast China is one of the severe soil degradation areas in China. This paper theoretically examines the impact of some important institutional arrangements and policies, like land management pattern, the rural off-farm employment, land property change and changes in prices of agricultural products, on soil degradation in this area. It further conducts some case studies to confirm the potential relationship between the institutions & policies and soil degradation, applying the surveyed and the second hand data. The paper at last makes some conclusions and proposes some suggestions on how to promote soil conservation by improving the ways of policy decision-making and the effects of policies on land use.     

Influencing Factors of the Levels of Intensive Use of Typical Industrial Land

The article establishes an evaluation index system of the intensive land use from the perspective of enterprises. It is based on the questionnaire survey and evaluates the levels of the intensive use of the land in the electrical machinery and equipment manufacturing industry in Changzhou, Nantong, and Yancheng of Jiangsu Province. The evaluation result shows that there is obvious difference in the levels of the intensive use of the land in this industry in the three cities. The present article makes a detailed analysis on the causes of the difference. The analysis shows difference in results of the socio-economic and urban development stage, industrial features, population density, and technological progress. Finally, it proposes some suggestions to improve the efficiency of the industrial land use.     

Analysis of BIM application relationship with integration degree of construction environment

As the world pays more attention to low-earbon and sustainable development,there’s a growing trend in architecture,engineering and construction fields to construct greener,more energy efficient and more sustainable buildings with the help of building information modeling(BIM).As BIM application becomes popular in industry,more and more scholars and engineers point out that an integrated construction environment is better for BIM’s fully functional capability.This paper illustrates the relationship between BIM application and an integrated construction environment based on case survey data.It is found that even though an integration construction environment is not necessary in BIM application,the statistical results showed that DBB(design-bid-build)and CM(construction management)modes have great differences in BIM’s application implementation scope and implementation deepness,while DB and CM modes do not.     

Experiment-based investigations on the effect of ignition energy on dust explosion behaviors

Explosion behaviors of typical light metal and carbonaceous dusts induced by different ignition energies were investigated based on systematic experiments in a Siwek 20 L vessel. Comparative analysis reveals that the explosion mechanism of carbonaceous dust is the volatile combustion, whereas the mechanism for light metal dust mainly features the surface heterogeneous oxidation. Influences of ignition energy on severity and flammability limit are much more significant for carbonaceous dust than light metal, especially for the powder with less volatile. An innovative approach was introduced to derive flame thickness from the pressure–time trace. The relation between explosion induction time and combustion duration of ignitor was also analyzed. Results show inappropriate ignition energy will cause under-/over-driving in the thermodynamic/kinetic characteristic measurements. In this way, a dimensionless parameter pressure ratio was introduced to evaluate the under-driving, while two methods by using flame thickness and induction time respectively, were proposed to evaluate over-driving. To improve the accuracy of dust explosion tests, authors advocate that explosion severity determination should be conducted at the critical ignition energy. Moreover, a comparison between the European and Chinese flammability limit determination procedures was also conducted, indicating that EN 14034-3 is suitable for light metal but not for carbonaceous, while GB/T 16425 appears to be slightly conservative for both carbonaceous and light metal dusts.     

On–off control of aeration time in the simultaneous removal of ammonia and manganese using a biological aerated filter system

The biological aerated filter (BAF) system, a new alternative in drinking water treatment, was designed to remove NH₄⁺–N and Mn²⁺ simultaneously. This study aimed to control the aeration time in the BAF system for simultaneous NH₄⁺–N and Mn²⁺ removal to achieve the Malaysian effluent quality regulation for drinking water. The experiment was conducted under four strategies of S1, S2, S3 and S4. The results demonstrated that acceptable levels of NH₄⁺–N and Mn²⁺ were achieved over a 6 h aeration period (S1), producing effluent concentrations of 0.7 mg/L (93.2% removal) and 0.08 mg/L (79.6% removal), respectively. At the initial treatment of S1 and S2, the dissolved oxygen (DO) level rapidly increased until it reached a saturated concentration (6.8 mg/L DO) after 2 h period. Automatic on–off aeration time to maintain 3 mg/L DO set point (S4) resulted with a good effluent quality of NH₄⁺–N and Mn²⁺ compared with the 2 mg/L DO set point (S3) which did not meet the regulated standard limits. Through the automatic on–off aeration time, the saturated and excessive DO levels in the BAF system can be avoided consequently reduce the wastage of energy and electrical consumption for simultaneous NH₄⁺–N and Mn²⁺ removal from drinking water treatment.     

High-performance Si-Containing anode materials in lithium-ion batteries:A superstructure of Si@Co–NC composite works effectively

To mitigate the massive volume expansion of Si-based anode during the charge/discharge cycles, we synthesized a superstructure of Si@Co–NC composite via the carbonization of zeolite imidazolate frameworks incorporated with Si nanoparticles. The Si@Co–NC is comprised of Si-nanoparticle core and N-doped/Co-incorporated carbon shell, and there is void space between the core and the shell. When using as anode material for LIBs, Si@Co–NC displayed a super performance with a charge/discharge capacity of 191.6/191.4 mA h g-1 and a coulombic efficiency of 100.1％ at 1000 mA g-1 after 3000 cycles, and the capacity loss rate is 0.022％ per cycle only. The excellent electrochemical property of Si@Co–NC is because its electronic conductivity is enhanced by doping the carbon shell with N atoms and by incorporating with Co particles, and the pathway of lithium ions transmission is shortened by the hollow structure and abundant mesopores in the carbon shell. Also, the volume expansion of Si nanoparticles is well accommodated in the void space and suppressed by the carbon host matrix. This work shows that, through designing a superstructure for the anode materials, we can synergistically reduce the work function and introduce the confinement effect, thus significantly enhancing the anode materials' electrochemical performance in LIBs.     

Steel slag quality control for road construction aggregates and its environmental impact: case study of Vietnamese steel industry—leaching of heavy metals from steel-making slag

Environmental Science and Pollution Research - Steel slag is an industrial by product of steel manufacturing processes and has been widely utilized within civil and construction materials for road...     

Predictions for isomer distributions of toxic dioxins and furans in selected industrial combustion processes

Three thermodynamic databases of polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) have been used to simulate the PCDD/F isomer distribution in industrial combustion processes. The three databases had been derived using the Group Additivity approach and two computational molecular modelling methods, Modified Neglect of Diatomic Overlap (MNDO) and Parametrized Model 3 (PM3), respectively. The predictions of the toxic PCDD/F isomer distributions using the three different databases have been compared with measured values from industrial processes. An excellent agreement between the predictions using the MNDO method and the measured data has been obtained. It is concluded that the PCDD/F isomer distributions within each group observed in these combustion processes may be thermodynamically controlled.