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Ole H. Caspersen MSc PhD. Cecil C. Konijnendijk Anton S. Olafsson 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(2):7-20
Geografisk Tidsskrift, Danish Journal of Geography 106(2):7–20, 2006 In its Regional Plan of 2005, The Greater Copenhagen Authority (abbreviated as “HUR” in Danish) places special emphasis on the future recreational values associated with the regional green structure. In this paper, the development of the urban green structure in Greater Copenhagen is elaborated upon, focusing on land use changes and the effectiveness of regionally coordinated planning measures. EU MOLAND data are used to analyse the development of the region's green structure during the period 1954 to 1998. Analysis of two “green wedges” within the green structure illustrates that the development of the green recreational areas is the result of both formal and more informal planning initiatives. Development has shown equal phases that correspond to the applied regional planning measures and the general economic conditions. However, local preferences in the involved municipalities likewise have played an important role and have resulted in different urbanisation pressure within the two wedges. Land use has transformed from an agricultural to a primarily recreational landscape. In some areas, however, urbanisation pressure has resulted in residential and green industrial areas instead of the planned recreational land use. Based on its historical development it is concluded that future preservation and development of the green structure in Greater Copenhagen requires regional planning measures to be incorporated into municipal plans. In this way the increasingly independent municipalities will comply to objectives of the Regional Plan 2005. 相似文献
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Y. C. Zhao Ph.D. X. Y. Yi Ph.D. M. Zhang MSc. L. Liu W. J. Ma 《International Journal of Environmental Science and Technology》2010,7(2):359-366
This research describes application of laccase from white-rot fungi (polyporus) to remove dichlorodiphenyltrichloroethane in soil. The degradation kinetics of dichlorodiphenyltrichloroethane in soil was also investigated by laboratory batch experiments. The results showed that laccase from white-rot fungi can effectively degrade dichlorodiphenyltrichloroethane and the degradation of total dichlorodiphenyltrichloroethane (the sum of the four dichlorodiphenyltrichloroethane compounds in a sample) was pseudo-first-order kinetics. The residues of almost all the dichlorodiphenyltrichloroethane components and total dichlorodiphenyltrichloroethane in soils treated with laccase decreased rapidly during first 15 days and then kept at a stable level during next 10 days. The residues of total dichlorodiphenyltrichloroethane in soils with different dosages laccase decreased by about 21–32 %, 29–45%, 35–51 % and 36–51 % after 5, 10, 15 and 25 days of incubation, respectively. The half-life of total dichlorodiphenyltrichloroethane in soils with different dosages laccase ranged from 24.75 to 41.75 days. The residues of total dichlorodiphenyltrichloroethane in three different types of soils decreased by 25–29 %, 39–43 %, 44–47 % and 47–52 % after 5, 10, 15 and 25 days of incubation with laccase, respectively. The half-life of total dichlorodiphenyltrichloroethane in different types of soil ranged from 24.71 to 27.68 days. The residues of total dichlorodiphenyltrichloroethane in soils with different pH levels decreased by 18–24 %, 29–39 %, 36–39 % and 39–50% after 5, 10, 15 and 25 days of incubation with laccase, respectively. The half-life of total dichlorodiphenyltrichloroethane ranged from 25.63 to 36.42 days. Laccase can be an efficient and safe agent for remediation of dichlorodiphenyltrichloroethane-contaminated soil. 相似文献
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M. A. Sheikh N. M. Noah BSc. MSc. K. Tsuha BSc. MSc. T. Oomori Professor 《International Journal of Environmental Science and Technology》2007,4(1):49-59
Surface sediment samples were collected from Tanzanian major commercial ports and studied for the distribution and behavior of tributyltin (TBT) compounds and heavy metals. The content of TBT in sediments ranged from ND-3670 ng (Sn) g1dry wt (1780 ± 1720) (Mean ± SD) at Zanzibar and from ND-16700 ng (Sn)g1 dry wt (4080 ± 7540) at Dar es Salaam ports, respectively. Maximum TBT levels were detected inside the both ports. Metabolic degradation of butyltin compounds (BTCs) showed that MBT + DBT > TBT %, this may be attributed by the warm ambient water and intense sunlight in the tropical regions. A sequential extraction procedure was undertaken to provide detailed chemical characteristics of heavy metals in the sediments. The procedure revealed that about 50% of Fe in the both ports is in immobile fraction (residual fraction) while other metals; Cd, Cu, Ni, Co, Zn, Pb, and Mn were mostly found in exchangeable or carbonate fractions and thus can be easily remobilized and enter the aquatic food chain. This paper provides basic information of TBT compounds contamination and chemical characteristics of heavy metals in the marine ecosystem in Tanzania. To our knowledge, this is the first documentation of Organotin compounds (OTCs) in marine environments in East Africa and suggests the importance of further detailed OTCs studies in other sub-Saharan Africa regions 相似文献
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Y. He MSc Ph.D. C. Duan MSc Ph.D. H. Wang MSc Ph.D. Y. Zhao MSc Ph.D. D. Tao MSc Ph.D. 《International Journal of Environmental Science and Technology》2011,8(1):73-82
Separation of metal laden solid wastes for their recycling utilization using passive pulsed air and active pulsing air classifiers was studied. Laboratory investigation showed that the active pulsing air separator performs more efficiently than the passive pulsed air separator due to the ability to accurately control operating parameters. By studying the difference of drag coefficients of the particles moving through the airflow of varying Reynolds numbers, models of the dynamic particle motion were developed and a computer simulation was prepared. Results of the simulation were reported to predict the observed results with artificial tracing spheres being separated by the laboratory equipment. Two different, real world feed materials were separated with the laboratory scale active pulsing air classifier. The discarded catalyst consisting of precious metal components and sintered magnetic beads was separated with the separation efficiency, of 97.6 %. The second real-world feed, electronic scrap crushed to a size of 0.5 to 2 mm, showed a separation efficiency of 92.41 %. At the same time, the grade of the recovered concentrate of metals was above 98 %. 相似文献
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Major Mark C Breach MA MSc ARICS RE 《Journal of Geodesy》1985,59(3):221-232
A method of determining azimuth by gyrotheodolite without electronic registration is described. The method requires observations
of time at each instant the moving mark passes a scale division. Thus many observations of time may be achieved in a single
oscillation of the moving mark. The observations when used in the appropriate observation equation may determine azimuth with
a standard error of ±3″ with 2 hours of observations. This assumes knowledge of the additive constant to about 1″.3 and neglects
the effects of dislevelment in the prime vertical. For practical application of the method a time recording device and microcomputer,
such as the Hewlett Packard HP41CV and HP85, are recommended. 相似文献
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Biodiesel production using solid metal oxide catalysts 总被引：1，自引：1，他引：0
A. A. Refaat BSc. MSc. 《International Journal of Environmental Science and Technology》2011,8(1):203-221
Biodiesel production is worthy of continued study and optimization of production procedures due to its environmentally beneficial attributes and its renewable nature. Heterogeneous transesterification is considered to be a green process. The process requires neither catalyst recovery nor aqueous treatment steps and very high yields of methyl esters can be obtained, close to the theoretical value. However, heterogeneously catalyzed transesterification generally requires more severe operating conditions, and the performance of heterogeneous catalysts is generally lower than that of the commonly used homogeneous catalysts. Heterogeneous catalysis for biodiesel production has been extensively investigated in the last few years. Many metal oxides have been studied for the transesterification process of oils; these include alkali earth metal oxides, transition metal oxides, mixed metal oxides and supported metal oxides. The use of solid metal oxides as catalysts in oil transesterification is well established, accordingly, researchers’ attempts are now focused on how to attain the highest catalyst activity. Catalyst activity is a function of its specific surface area, base strength and base site concentration. High specific surface area, strong base strength and high concentration of base sites are characteristics of an active transesterification catalyst. This review provides a brief overview of the different metal oxides frequently used in the process of transesterification of oils for the production of biodiesel with special reference to the various methods of catalyst preparation and catalyst characterization. Reaction conditions and catalyst leaching analysis are also highlighted. Finally, concluding remarks regarding catalyst selection and catalyst preparation steps are provided. 相似文献
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