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Effectiveness of China’s protected areas in reducing deforestation Texte intégral
2019
Yang, Hongbo | Viña, Andrés | Winkler, Julie Ann | Chung, Min Gon | Dou, Yue | Wang, Fang | Zhang, Jindong | Tang, Ying | Connor, Thomas | Zhao, Zhiqiang | Liu, Jianguo
Protected areas (PAs) are considered a cornerstone of biodiversity conservation, and the number and extent of PAs are expanding rapidly worldwide. While designating more land as PAs is important, concerns about the degree to which existing PAs are effective in meeting conservation goals are growing. Unfortunately, conservation effectiveness of PAs and its underlying determinants are often unclear across large spatial scales. Using PAs in China as an example, we evaluated the effectiveness of 472 PAs established before 2000 in reducing deforestation between 2000 and 2015. Our results show that the majority (71%) of the PAs were effective in reducing deforestation. Without their establishment, deforestation within the PAs would have increased by about 50% (581 km²), with about 1271 megaton of carbon per year not being sequestered. We also found some attributes of PAs, including surrounding deforestation level, roughness of terrain, and travel time to the nearest city, are significantly related to their effectiveness in reducing deforestation. Our findings highlight the need of systematically evaluating the effectiveness of PAs and incorporating this effectiveness into conservation planning and management to more fully realize the goals of PAs not only in China but also around the world.
Afficher plus [+] Moins [-]Cost-effectiveness of boron (B) removal from irrigation water: an economic water treatment model (EWTM) for farmers to prevent boron toxicity Texte intégral
2019
Türker, Onur Can | Yakar, Anıl | Türe, Cengiz | Saz, Çağdaş
Protection of water sources which are used for irrigation has raised great interest in the last years among the environmental strategists due to potential water scarcity worldwide. Excessive boron (B) in irrigation water poses crucial environmental problems in the agricultural zones and it leads to toxicity symptoms in crops, as well as human beings. In the present research, economic water treatment models consist of dried common wetland plants (Lemna gibba, Phragmites australis, and Typha latifolia) and Lemna gibba accumulation was tested and assessed to create a simple, cost-effective, and eco-friendly method for B removal from irrigation water. Significant amount of B was removed from irrigation water samples by EWTMs and B concentrations decreased below < 1 mg L⁻¹ when the components were exposed to 4 and 8 mg L⁻¹ initial B concentrations. Moreover, the results from batch adsorption study demonstrated that dried L. gibba had a higher B loading capacity compare to other dried plants, and B sorption capacity of dried L. gibba was found as 2.23 mg/g. The optimum pH value for sorption modules was found as neutral pH (pH = 7) in the batch adsorption experiment. Boron sorption from irrigation water samples fitted the Langmuir model, mostly B removed from irrigation water during the first 2 h of contact time. Techno-economic analysis indicated that EWTM is a promising method that appears to be both economically and ecologically feasible, and it can also provide a sustainable and practical strategy for farmers to prevent B toxicity in their agricultural zones.
Afficher plus [+] Moins [-]Variability in Antarctic sea ice from 1998 to 2017 Texte intégral
2019
Wu, Zhankai | Wang, Xingdong
This study was based on the daily sea ice concentration data from the NASA Team algorithm from 1998 to 2017. The Antarctic sea ice was analyzed from the total sea ice area (SIA), first-year ice area, and multiyear ice area. On a temporal scale, the changes in sea ice parameters were studied over the whole 20 years. The results showed that the total SIA increased by 0.0087 × 10⁶ km² year⁻¹ (+ 2.08% dec⁻¹) between 1998 and 2017. The multiyear ice area increased by 0.0141 × 10⁶ km² year⁻¹ from 1998 to 2017. The first-year ice area decreased by − 0.0058 × 10⁶ km² year⁻¹ between 1998 and 2017. On a spatial scale, the entire Antarctic was divided into two areas, namely West Antarctica (WA) and East Antarctica (EA), according to the spatial change rate of sea ice concentration. The total sea ice and multiyear ice areas showed a decreasing trend in WA. However, the total SIA and multiyear ice area all showed an increasing trend in EA. Therefore, Antarctic sea ice presented an increasing trend, but there were different trends in WA and EA.
Afficher plus [+] Moins [-]Enhanced arsenate removal from aqueous solution by Mn-doped MgAl-layered double hydroxides Texte intégral
2019
Li, Shifeng | Guo, Yang | Xiao, Min | Zhang, Tan | Yao, Shuhua | Zang, Shuyan | Fan, Hongtao | Shen, Yanming | Zhang, Zhigang | Li, Wenxiu
In this study, Mn-doped MgAl-layered double hydroxides (LDHs) were successfully synthesized for efficient removal arsenate from aqueous solution. The structure and composition of Mn-doped MgAl-LDHs intercalated by different ions such as CO₃²⁻, Cl⁻, or NO₃⁻ were investigated. The characterizations of XRD, ATR FT-IR, SEM, TG-DTA, and N₂ adsorption-desorption presented that the Mn-doped MgAl-LDHs (donated as Mn-LDHs) have very similar physical morphologies and properties to the MgAl-Cl-LDHs (donated as Mg-LDHs). However, the Mn-LDHs exhibits more preferable arsenate adsorption than Mg-LDHs. The As(V) removal kinetics data of Mn-LDHs is followed pseudo-second-order expression. The adsorption capacity of As(V) on Mn-LDHs via Langmuir isotherm model was 166.94 mg g⁻¹. The results of XPS revealed that the enhanced removal mechanism can be attributed to surface complexation of As(V) with Mn on the surface of Mn-LDHs. These results prove that Mn-doped LDHs can be considered as a potential material for adsorption As(V) from wastewater.
Afficher plus [+] Moins [-]Re-visiting environmental Kuznets curve: role of scale, composite, and technology factors in OECD countries Texte intégral
2019
Sohag, Kazi | Kalugina, Olga | Samargandi, Nahla
This study assesses environmental Kuznets curve (EKC) hypothesis corroborating the role of scale, composite, and technology effects in OECD countries. To this end, we analyze the panel time series data from 1980 to 2017 using cross-sectional-autoregressive distributed lags (CS-ARDL). We document that economic growth and carbon emissions follow a U-shaped relationship, contrary to the EKC hypothesis, which our analysis attributes to the substantial contributions of the industrial, manufacturing, and service sectors to GDP. Technological progress has a somewhat marginal impact in reducing carbon emissions through energy efficiency but is unable to validate the existence of EKC hypothesis.
Afficher plus [+] Moins [-]Long-term spatiotemporal variations of aerosol optical depth over Yellow and Bohai Sea Texte intégral
2019
Shen, Xiaojing | Vēlāyutan̲, T. A. | Qiu, Zhongfeng | Sun, Deyong | Wang, Shengqiang | Zhu, Weijun
In this study, MODerate resolution Imaging Spectroradiometer (MODIS) Collection 6.1 (C6.1) level-2 Dark Target (DT) Aerosol Optical Depth (AOD) observations at 550 nm (AOD₅₅₀) for the highest quality flag assurance (QA = 3) were obtained to analyze spatiotemporal variations of aerosol optical properties over the Yellow and the Bohai Sea from 2002 to 2017. Spectral AOD observations at 470 nm (AOD₄₇₀) and 660 nm (AOD₆₆₀) were obtained to calculate Angstrom Exponent (AE₄₇₀–₆₆₀) and classify the aerosol types including clean continental (CC), clean maritime (CM) biomass and urban industrial (BUI), dust (D), and mixed (MXD) aerosol types. Results showed a very distinct spatial pattern of AOD distribution over the Bohai Sea which looks suspicious, i.e., high aerosol loadings (AOD > 0.8) throughout the entire time period, whereas relative low AOD distribution was observed over the adjacent land pixels especially in autumn and winter, which suggested that the DT algorithm might be influenced by a large number of sediments located in the Bohai Sea. Significant differences in spatial distributions were found in different seasons in terms of area coverage as a maximum number of pixels were available during autumn, and regional high and low aerosol loadings were observed during autumn and summer, respectively. Trend analysis from 2002 to 2017 showed that AOD was increased up to 0.04 over the Bohai Sea and decreased up to 0.04 over the Yellow Sea, and this trend varies from month to month. Aerosol classification showed significant contributions of BUI and CC over the region, and contributions of CM, DUST, and MXD aerosols over the Yellow Sea were relatively high compared to the Bohai Sea.
Afficher plus [+] Moins [-]Assessment of Melissa officinalis L. essential oil as an eco-friendly approach against biodeterioration of wheat flour caused by Tribolium castaneum Herbst Texte intégral
2019
Upadhyay, Neha | Singh, Vipin Kumar | Dwivedy, Abhishek Kumar | Das, Somenath | Chaudhari, Anand Kumar | Dubey, N. K.
The study reports efficacy of Melissa officinalis L. essential oil (MOEO) as a safe plant-based insecticide against Tribolium castaneum Herbst (TC) by induction of oxidative stress. MOEO nanoencapsulation in chitosan matrix was performed to enhance its bioefficacy. GC–MS analysis of MOEO depicted geranial (31.54%), neral (31.08%), and β-caryophyllene (12.42%) as the major components. MOEO showed excellent insecticidal potential in contact (100% mortality at 0.157 μL/cm²) and fumigant bioassays (LC₅₀ = 0.071 μL/mL air) and 100% repellency at concentration ≤ 0.028 μL/cm². Increased reactive oxygen species (ROS), superoxide dismutase (SOD), catalase (CAT), and decreased ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) at the LC₅₀ dose suggested significant oxidative stress on TC in MOEO treatment sets. The encapsulated MOEO exhibited enhanced activity as fumigant (LC₅₀ = 0.048 μL/mL air) and showed significant antifeedant activity in situ (EC₅₀ = 0.043 μL/mL). High LD₅₀ value (13,956.87 μL/kg body weight of mice) confirmed favorable toxicological profile for non-target mammals. The findings depict potential of nanoencapsulated MOEO as an eco-friendly green pesticide against infestation of stored food by TC.
Afficher plus [+] Moins [-]Sensitivity analysis of the reference crop evapotranspiration in a humid region Texte intégral
2019
Biazar, Seyed Mostafa | Dinpashoh, Yagob | Singh, V. P. (Vijay P.)
This study examined the sensitivity of reference crop evapotranspiration (ET₀) to climatic variables in a humid region in Iran. ET₀ was estimated using the FAO-56 Penman–Monteith (PMF-56), Blaney–Criddle (BC), and Hargreaves–Samani (HG) methods. Sensitivity analysis was performed by two distinct methods which were (i) changing the value of a certain climatic parameter in a range between ± 20% of its long-term mean with an increment of 5%, and calculating the percentage of change in ET₀, while the other parameter values were kept constant; and (ii) calculating the sensitivity coefficients (SCs) for each of the climatic variables. For each of the climatic parameters, the Iso-SC maps were plotted using the Arc-GIS software. Results indicated that the most sensitive parameter for ET₀ was the maximum air temperature (Tₘₐₓ) by PMF-56 and HG methods. Increasing Tₘₐₓ up to 20% led to an increase in ET₀ between 8.5 and 15%, at the selected stations by PMF-56. In contrast, the less sensitive parameter for ET₀ was the minimum air temperature (Tₘᵢₙ) for PMF-56 and Tₘₑₐₙ for HG. For PMF-56, increasing the minimum relative humidity (RHₘᵢₙ) to 20% led to a decrease in ET₀ in the range between 0.5 and 5%. The highest values of SC in the cases of Tₘₐₓ and Tₘᵢₙ were found to be equal to 0.8 and 0.53, respectively. Similarly, the SC in the case of RHₘᵢₙ varied between − 0.29 and − 0.0038. This range for wind speed was between 0.06 and 0.22 and in the case of sunshine hours it was between 0.272 and 0.385. These findings would be useful in the scientific management of water resources in the region.
Afficher plus [+] Moins [-]The origin of high hydrocarbon groundwater in shallow aquifer: experimental evidences from water-rock interaction Texte intégral
2019
Liu, Shan | Qi, Shihua | Luo, Zhaohui | Mapoma, Harold Wilson T. | Chen, Zhihua | Cheng, Shenggao
The current studies had already revealed the hydrocarbons could migrate from relatively high hydrocarbon potential stratum to shallow groundwater by corrosion emission and extraction emission in karst area and further impact on human health. Then, the comprehensive experiments were used to understand the mechanism and process of hydrocarbon emission as a continuation of a long-term study on original high hydrocarbon groundwater in shallow Triassic aquifer, taking northwest Guizhou, China, as a reference. The results determined water-rock interaction that lead to the hydrocarbon emission into groundwater with salinity acting as the main driving force. Relatively high salinity promotes the rock corrosion and hydrocarbon emission in the study area. The hydrocarbon emission process varied with different strata, as the results show that the hydrocarbon uniformly distributed in T₂g³ than that in T₁yn⁴. Furthermore, the stratum with uniformly distributed hydrocarbon would likely contain high hydrocarbon groundwater, as determined by the process of sedimentation. In addition, “corrosion rate estimation method” and “mineral constituent estimation method” were firstly employed to estimate the hydrocarbon concentration in groundwater to date. Compared with the hydrocarbon concentration of local groundwater samples (0 to 0.14 mg L⁻¹), the result of “mineral constituent estimation method” was analogous to measured value of groundwater samples in the area (0.05 to 0.50 mg L⁻¹), indicating the concentration of hydrocarbon could be estimated by mineral constitutions of groundwater, which was related to the concentration of Ca²⁺ and Mg²⁺. Based on the methods and theories in this study, the concentration of original hydrocarbon in shallow groundwater could be estimated and help to understand the mechanism of water-rock interaction in shallow aquifer and original high hydrocarbon groundwater strategic assessment.
Afficher plus [+] Moins [-]Impact of stabilizer on the environmental behavior of PVC films reinforced 1,2,4-triazole moiety Texte intégral
2019
Yousif, Emad | Ahmed, Dina S. | Ahmed, Ahmed | Abdallh, Mustafa | Yusop, Rahimi M. | Mohammed, Salam A.
A new Schiff base containing 1,2,4-triazole ring system (L) was synthesized and confirmed by ¹HNMR, FTIR spectroscopy. The chemical modification of PVC with a new Schiff base (L) was synthesized to produce a homogenous blend (PVC-L). A homogenous blend (PVC-L) was added to copper chloride to produce PVC-L-Cu (II). The PVC films had been irradiated with ultraviolet light for a long period and confirmed by FTIR spectroscopy and weight loss; the surface morphology was inspected by scanning electron microscopy.
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