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271.
Po-Hsin Lai Michael G. Sorice Sanjay K. Nepal Chia-Kuen Cheng 《Environmental management》2009,43(6):985-998
High demand for outdoor recreation and increasing diversity in outdoor recreation participants have imposed a great challenge
on the National Park Service (NPS), which is tasked with the mission to provide open access for quality outdoor recreation
and maintain the ecological integrity of the park system. In addition to management practices of education and restrictions,
building a sense of natural resource stewardship among visitors may also facilitate the NPS ability to react to this challenge.
The purpose of our study is to suggest a segmentation approach that is built on the social marketing framework and aimed at
influencing visitor behaviors to support conservation. Attitude toward natural resource management, an indicator of natural
resource stewardship, is used as the basis for segmenting park visitors. This segmentation approach is examined based on a
survey of 987 visitors to the Padre Island National Seashore (PAIS) in Texas in 2003. Results of the K-means cluster analysis
identify three visitor segments: Conservation-Oriented, Development-Oriented, and Status Quo visitors. This segmentation solution
is verified using respondents’ socio-demographic backgrounds, use patterns, experience preferences, and attitudes toward a
proposed regulation. Suggestions are provided to better target the three visitor segments and facilitate a sense of natural
resource stewardship among them. 相似文献
272.
Robert Dilmore Craig Griffith Zhu Liu Yee Soong Sheila W. Hedges Richard Koepsel Mohammad Ataai 《International Journal of Greenhouse Gas Control》2009,3(4):401-410
A novel CO2 separation concept is described wherein the enzyme carbonic anhydrase (CA) is used to increase the overall rate of CO2 absorption after which hydrated CO2 reacts with regenerable amine-bearing polyacrylamide buffering beads (PABB). Following saturation of the material's immobilized tertiary amines, CA-bearing carrier water is separated and recycled to the absorption stage while CO2-loaded material is thermally regenerated. Process application of this concept would involve operation of two or more columns in parallel with thermal regeneration with low-pressure steam taking place after the capacity of a column of amine-bearing polymeric material was exceeded. PABB CO2-bearing capacity was evaluated by thermogravimetric analysis (TGA) for beads of three acrylamido buffering monomer ingredient concentrations: 0 mol/kg bead, 0.857 mol/kg bead, and 2 mol/kg bead. TGA results demonstrate that CO2-bearing capacity increases with increasing PABB buffering concentration and that up to 78% of the theoretical CO2-bearing capacity was realized in prepared PABB samples (0.857 mol/kg recipe). The highest observed CO2-bearing capacity of PABB was 1.37 mol of CO2 per kg dry bead. TGA was also used to assess the regenerability of CO2-loaded PABB. Preliminary results suggest that CO2 is partially driven from PABB samples at temperatures as low as 55 °C, with complete regeneration occurring at 100 °C. Other physical characteristics of PABB are discussed. In addition, the effectiveness of bovine carbonic anhydrase for the catalysis of CO2 dissolution is evaluated. Potential benefits and drawbacks of the proposed process are discussed. 相似文献
273.
Andrew Keats Man-Ting Cheng Eugene Yee Fue-Sang Lien 《Atmospheric environment (Oxford, England : 1994)》2009,43(3):510-519
The chemical mass balance (CMB) receptor model is commonly used in source apportionment studies as a means for attributing measured airborne particulate matter (PM) to its constituent emission sources. Traditionally, error terms (e.g., measurement and source profile uncertainty) associated with the model have been treated in an additive sense. In this work, however, arguments are made for the assumption of multiplicative errors, and the effects of this assumption are realized in a Bayesian probabilistic formulation which incorporates a ‘modified’ receptor model. One practical, beneficial effect of the multiplicative error assumption is that it automatically precludes the possibility of negative source contributions, without requiring additional constraints on the problem. The present Bayesian treatment further differs from traditional approaches in that the source profiles are inferred alongside the source contributions. Existing knowledge regarding the source profiles is incorporated as prior information to be updated through the Bayesian inferential scheme. Hundreds of parameters are therefore present in the expression for the joint probability of the source contributions and profiles (the posterior probability density function, or PDF), whose domain is explored efficiently using the Hamiltonian Markov chain Monte Carlo method. The overall methodology is evaluated and results compared to the US Environmental Protection Agency's standard CMB model using a test case based on PM data from Fresno, California. 相似文献
274.
Polybrominated diphenyl ethers (PBDEs) can be metabolically converted to their hydroxylated metabolites (OH-PBDEs). The estrogenic effects of PBDEs may be mediated by OH-PBDEs, but the mechanisms of which are still not understood. This study investigated the glucuronidation of 11 OH-PBDEs and their potential in modulating UDP-glucuronosyltransferases (UGTs) activity of 17β-estradiol (E2) in rat liver microsomes. The number of bromine atoms at phenolic ring was observed as the most influential factor of OH-PBDEs glucuronidation. 2′-OH-BDE-28 having one bromine atom at phenolic ring showed the fastest metabolic rates with t1/2 value of 3.86 min, while 6-OH-BDE-137 having four bromine atoms at phenolic ring was the poorest substrate with t1/2 value over 60 min. Regarding to the modulation of E2-UGTs activity, the phenolic hydroxyl group in OH-PBDEs played an essential role. Depending on the substitution patterns of bromine and hydroxyl group, OH-PBDEs inhibited or stimulated E2-UGTs activity. Ten of OH-PBDEs inhibited both 3-glucuronidation and 17-glucuronidation of E2 with IC50 values varying from 3.80 to 129.38 μM, while 3′-OH-BDE-100 exhibited stimulating effects on 3-glucuronidation with EC50 value of 35.95 μM. Kinetic analysis suggested noncompetitive inhibition mode of E2 glucuronidation by 3′-OH-BDE-7, 6-OH-BDE-47 and 2′-OH-BDE-68 with Ki values varying from 11.95 to 67.22 μM. This study demonstrated OH-PBDEs exhibited large interindividual differences in glucuronidation and modulation of E2-UGTs activity. By inhibiting the formation of E2 glucuronidation, OH-PBDEs may increase E2 bioavailability in target tissue, thereby exerting an indirect estrogenic effect. 相似文献
275.
Biodegradation of pentaerythritol tetranitrate (PETN) by anaerobic consortia from a contaminated site 总被引:1,自引:0,他引:1
This study examined the role of denitrifying and sulfate-reducing bacteria in biodegradation of pentaerythritol tetranitrate (PETN). Microbial inocula were obtained from a PETN-contaminated soil. PETN degradation was evaluated using nitrate and/or sulfate as electron acceptors and acetate as a carbon source. Results showed that under different electron acceptor conditions tested, PETN was sequentially reduced to pentaerythritol via the intermediary formation of tri-, di- and mononitrate pentaerythritol (PETriN, PEDN and PEMN). The addition of nitrate enhanced the degradation rate of PETN by stimulating greater microbial activity and growth of nitrite reducing bacteria that were responsible for degrading PETN. However, a high concentration of nitrite (350 mg L−1) accumulated from nitrate reduction, consequently caused self-inhibition and temporarily delayed PETN biodegradation. In contrast, PETN degraded at very similar rates in the presence and absence of sulfate, while PETN inhibited sulfate reduction. It is apparent that denitrifying bacteria possessing nitrite reductase were capable of using PETN and its intermediates as terminal electron acceptors in a preferential utilization sequence of PETN, PETriN, PEDN and PEMN, while sulfate-reducing bacteria were not involved in PETN biodegradation. This study demonstrated that under anaerobic conditions and with sufficient carbon source, PETN can be effectively biotransformed by indigenous denitrifying bacteria, providing a viable means of treatment for PETN-containing wastewaters and PETN-contaminated soils. 相似文献
276.
Juang KW Lee YI Lai HY Wang CH Chen BC 《Environmental science and pollution research international》2012,19(4):1315-1322
Purpose
Although the ecotoxicological effects of copper (Cu) on grapevine are of global concern due to the intensive and long-term application of Cu-based fungicides in vineyards, comparatively little is known about the phytotoxicity, accumulation, and translocation of Cu in grapevines. Therefore, this study was to conduct a hydroponic experiment to determine the influence of solution Cu concentration not only on bioaccumulation and the translocation of Cu in grapevine roots, stems, and leaves, but also on the subsequent growth inhibition of the roots. 相似文献277.
常压制备秸秆活性炭对水溶液中磷元素的吸附 总被引:1,自引:0,他引:1
开发了非真空制备秸秆活性炭的新方法,以稻草秸秆为原料,醋酸钙和氯化锌为活化剂,经热处理,一步合成改性秸秆活性炭。XRD图谱显示,产物为碳酸钙改性活性炭;SEM和TEM的表征结果显示,该活性炭具有微米-纳米多维孔结构,碳酸钙颗粒均匀分布在活性炭的表面和基体中;BET比表面积实验测得不同浓度碳酸钙改性活性炭的比表面积在324~846 m2/g之间。含磷水溶液吸附实验表明,当改性活性炭中碳酸钙含量为1.5%时,活性炭具有最大吸附速率1.76 L/mg;碳酸钙含量为2.0%时,活性炭具有最大吸附容量3.21 mg/g。改性活性炭对磷元素的吸附过程符合Langmuir模型,说明改性活性炭对磷的吸附为单分子层吸附。 相似文献
278.
Yu-Huei Peng Yang-hsin Shih Yen-Chun Lai Yuan-Zan Liu Ying-Tong Liu Nai-Chun Lin 《Environmental science and pollution research international》2014,21(16):9529-9537
The increasing usage and the persistence of polyester polyurethane (PU) generate significant sources of environmental pollution. The effective and environmental friendly bioremediation techniques for this refractory waste are in high demand. In this study, three novel PU degrading bacteria were isolated from farm soils and activated sludge. Based upon 16S ribosomal RNA gene sequence blast, their identities were determined. Particularly robust activity was observed in Pseudomonas putida; it spent 4 days to degrade 92 % of Impranil DLNTM for supporting its growth. The optimum temperature and pH for DLN removal by P. putida were 25 °C and 8.4, respectively. The degradation and transformation of DLN investigated by Fourier transformed infrared spectroscopy show the decrease in ester functional group and the emergence of amide group. The polyurethanolytic activities were both presented in the extracellular fraction and in the cytosol. Esterase activity was detected in the cell lysate. A 45-kDa protein bearing polyurethanolytic activity was also detected in the extracellular medium. This study presented high PU degrading activity of P. putida and demonstrated its responsible enzymes during the PU degradation process, which could be applied in the bioremediation and management of plastic wastes. 相似文献
279.
Darren Delai Sun Lilin Zhang Dickson Lai 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1469-1473
Disposal of mercury waste has always provided unique challenges due to its high degree of complexity and volatility. This study evaluated the feasibility of using waste LF slag to form a cementitious matrix capable of providing an effective stabilization/solidification solution for the treatment of mercury wastes. The new matrix was synthesized and simulated through a combination of alkali activation and autoclaving process and doped with mercury nitrate at increasing dosage while monitoring the final form of the mercury and its effects on the mineral stability and structure of the new matrix. Compressive strength of up to 20 N/mm2 was achievable for the original matrix. Promising results were obtained in terms of reduced leachability of the mercury when compared to ordinary Portland cement systems at low doping concentration of around 0.5% by weight. A series of precipitation reactions was found to be the main cause responsible for this successful stabilization, especially the metal sulfide precipitation that occurred with the sulfur present in the original waste LF slag.
Implications: Using waste to treat waste as a concept is a new approach that not only solves waste disposal problems but also minimizes the toxicity and the potential hazard of leaching of heavy metals. This study evaluated the feasibility of using waste ladle furnace slag generated from steel-making industries to form a cementitious matrix capable of providing an effective stabilization/solidification solution for the treatment of mercury-containing wastes. Promising results were obtained, and it clearly showed this approach is feasible, which could be a one-stone-kills-two-birds solution for mercury stabilization as well as an industrial waste disposal problem. 相似文献
280.
采用共沉淀-浸渍法制备了固体超强酸SO24-/TiO2-SnO2/Ce4+,并用XRD、SEM等方法对其结构进行了表征。以苯酚的光催化降解为反应模型,确定了最佳的工艺条件和催化剂再生方法。结果表明:在pH值为6,苯酚初始浓度为50mg/L,催化剂投加量4 g/L,光照距离12 cm,光照时间为150 min,降解率达67.73%,添加助催化剂H2O2后,反应60 min,苯酚降解率达到86.33%,催化剂的最佳再生方法是先用1 mol/L的硫酸浸渍24 h后,在450℃下焙烧6 h。 相似文献