خيارات البحث
النتائج 4521 - 4530 من 8,010
Nanoscale zero-valent iron particles supported on MIL-96: a novel material for adsorption-degradation of trichloronitromethane النص الكامل
2021
Zhang, Beibei | Tian, Ye | Liu, Junshen | Gao, Xuezhen | Zheng, Hui
As an emerging class of nitrogenous disinfection by-products, halonitromethanes have caused public health concerns owing to their high toxicity. More and more attention has been paid to the new materials and technologies for the removal of halonitromethanes. In this study, a novel material, nanoscale zero-valent iron (nZVI) supported on MIL-96 (nZVI@MIL-96) with favorable stability and reusability, was synthesized and applied to the adsorption-degradation of trichloronitromethane (TCNM) in the water. The results revealed that almost all the TCNM could be removed under 20 mg/L nZVI@MIL-96 dosage with a wide temperature range. The optimum mass ratio of nZVI to MIL-96 was 1:2, and the TCNM adsorption-degradation followed a pseudo-first-order model. The coexisting ions, such as SO₄²–, PO₄³–, and NO₃–, with high concentration brought adverse effects on the removal of TCNM; however, the effects of Cl– and CO₃²– were insignificant. The concentrations of aluminum and iron ions in water were all within the standard value after adsorption with the nZVI@MIL-96. The degradation mechanism of TCNM by nZVI@MIL-96 included two steps, namely, adsorption and degradation, and methylamine was the terminal dechlorination and denitration products. In a word, the as-prepared nZVI@MIL-96 nanoparticles demonstrated the capabilities as a material of adsorption-degradation of TCNM in the water.
اظهر المزيد [+] اقل [-]Economic complexity, tourism, energy prices, and environmental degradation in the top economic complexity countries: fresh panel evidence النص الكامل
2021
Abbasi, Kashif Raza | Lv, Kangjuan | Radulescu, Magdalena | Shaikh, Pervez Ahmed
The study explores the association between economic complexity index (ECI), tourism (TR), gross domestic products (GDP), gross domestic products per capita (GPC), and energy prices indices (EPI) on CO₂e using the top 18 economic complexity index countries data from 1990 to 2019. We employ the second-generation cointegration methods and cross-sectionally augmented autoregressive distributed lag (CS-ARDL) to analyze the short- and long-term association also Dumitrescu and Hurlin Granger causality test applied. The results of Pesaran and Yamagata slope heterogeneity and Pesaran CD test confirm the presence of cross-sectional unit relationship and slope heterogeneity across countries, while positive long- and short-term associations were found among ECI, GDP, and CO₂e. Also, TR, GPC, and EPI decrease carbon emissions both in the long and short term . Moreover, Augmented Mean Group (AMG) techniques verified and support these findings. The outcomes of the Dumitrescu and Hurlin Granger causality test showed that any policy aim at ECI, TR, GDP, GPC, and EPI has a considerable impact on CO₂e. Based on the rigorous empirical analysis, we suggest that economic complexity, tourism, GDP, GPC, and energy prices would help alleviate high economic complexity countries’ environmental degradation challenges.
اظهر المزيد [+] اقل [-]Value assessment for the restoration of industrial relics based on analytic hierarchy process: a case study of Shaanxi Steel Factory in Xi’an, China النص الكامل
2021
Liu, Yijun | Li, Huimin | Li, Wenlong | Li, Qin | Hu, Xin
Concomitant with the promotion of industrial transformation, sustainable development strategies, and accelerated urbanization, there has been an increase in the number of industrial relic restoration projects. However, there are many disputes over the value and development of such industrial relic restoration projects. In this work, we identified three evaluation indicators based on a study of 106 industrial relic restoration projects in China. A value assessment model composed of five parts combining the Delphi method and analytic hierarchy process was established. The results show that an effective assessment of the value of industrial relic restoration projects can enable the effective use of green technology, reduce construction costs, protect industrial heritage, and inherit historical culture. In addition, there are many uncertain factors in developing these projects, such as brownfield pollution and dilapidated buildings, and appropriate renewal strategies can reduce safety risks as well as maximize the heritage value. As there is limited research assessing the value of industrial relic restoration projects in China, our study can serve as a reference for the value assessment of existing building restoration projects including historical blocks and livable villages.
اظهر المزيد [+] اقل [-]Development of chitosan-coated nanoemulsions of two sulfides present in onion (Allium cepa) essential oil and their nematicidal activities against the pine wood nematode, Bursaphelenchus xylophilus النص الكامل
2021
Yang, Eunhye | Yi, Chae-u | Chang, Pahn-Shick | Park, Il-Kwon
Pine wood nematode, Bursaphelenchus xylophilus, is a plant parasitic nematode which causes severe damage to several Pinus species. Two natural compounds, dipropyl trisulfide (DPTS) and methyl propyl trisulfide (MPTS), showed strong nematicidal activity against the pine wood nematode, presenting 4.24 and 17.81 μg/mL LC₅₀ values, respectively. However, hydrophobicity and low stability have limited their practical use in the field as nematicides. To overcome these problems, chitosan-coated nanoemulsions of DPTS and MPTS were developed. The optimum chitosan concentration for the delivery system of the two sulfides was 0.5%. Optimized chitosan-coated nanoemulsions of sulfides have a uniform size distribution (mean diameter = 203.7 and 207.7 nm, mean polydispersity index = 0.176 and 0.178) with sufficient colloidal stability (mean zeta potential = +40 and +45 mV). The LC₅₀ values of DPTS and MPTS nanoemulsions coated with 0.5% chitosan against the pine wood nematode were 5.01 and 16.60 μg/mL, respectively. In addition, chitosan coating improved the long-term storage stability and persistence of nematicidal activity of the nanoemulsions. This study indicates that the chitosan-coated nanoemulsion is a suitable formulation for sulfides as novel nematicides against the pine wood nematode for field application.
اظهر المزيد [+] اقل [-]Biomass yield and carbon abatement potential of banana crops (Musa spp.) in Ecuador النص الكامل
2021
Ortiz-Ulloa, Juvenal Alejandro | Abril-González, Mónica Fernanda | Pelaez-Samaniego, Manuel Raúl | Zalamea-Piedra, Teresa Silvana
Banana is one of the most important agricultural products of Ecuador. It relies on intensive monoculture cropping systems with a large volume of standing biomass and large amounts of residual biomass that can be used for carbon sequestration. This study was performed (1) to quantify the yearly residual biomass generation, (2) to quantify the carbon stock of standing banana biomass, (3) to estimate the carbon sequestration potential by using the residual biomass generated yearly, and (4) to propose a biomass prediction model for banana crops in Ecuador. The study was conducted between March 2018 and January 2019 in the three main banana-producing provinces of Ecuador (Los Ríos, Guayas, and El Oro). Samples of rachis, pseudostem, leaves, and flowers from 36 banana plants of the variety Musa AAA Cavendish were taken for laboratory tests. Physical measurements such as height, circumferences, number of leaves, and weights were determined for the 36 plants. Results showed an average residue-to-product ratio of 3.79 and a country’s yearly biomass generation of 2.65 Mt on a dry basis. The carbon stock of the standing biomass was estimated as 4.18 ± 1.02 Mg/ha, 5.44 ± 0.96 Mg/ha, and 5.13 ± 1.11 Mg/ha for Los Ríos, Guayas, and El Oro, respectively. The estimated carbon abatement capacity of the residual biomass is 3.92 MtCO₂/year. Three biomass estimation models were developed in Python®, using the data collected in this study and least squares fitting for exponential models of the form: Y = AXⁿ + C. The models showed good prediction capacity for Ecuadorian banana plants, with R² up to 0.85. It is expected that this study could serve as the basis for studies on developing sustainable conversion processes of banana residual biomass.
اظهر المزيد [+] اقل [-]Groundwater quality evolution based on geochemical modeling and aptness testing for ingestion using entropy water quality and total hazard indexes in an urban-industrial area (Tiruppur) of Southern India النص الكامل
2021
Karunanidhi, D. | Aravinthasamy, P. | Deepali, M. | Subramani, T. | Bellows, Barbara C. | Li, Peiyue
This study used geochemical modeling to understand the chemical evolution of groundwater, entropy water quality index to assess the aptness of groundwater for human consumption, and total hazard index to determine the possible non-carcinogenic risks among children, women, and men in an urban-industrial area (Tiruppur region) of southern India. For the above purposes, 40 groundwater samples were collected from tube and dug wells, and they were tested for various physicochemical parameters. Fluoride and nitrate levels ranged from 0.10 to 2.70 mg/l and 10 to 290 mg/l, respectively. Nearly, 50% of the fluoride samples and 58% of the nitrate samples exceeded the WHO limits of 1.5 and 45 mg/l, respectively. The majority of the groundwater samples (22.5%) represented Ca²⁺-Na⁺-Cl⁻ water type while the remaining samples exhibited mixed water types. Approximately, 85% of the samples indicated high levels of salinization since they had Revelle index > 0.5 meq/l. The saturation index (SI) revealed that mineral weathering; dissolution of halite, gypsum, and anhydrite; and precipitation of calcite and dolomite contributed to groundwater chemistry. Based on the entropy water quality index (EWQI), none of the groundwater samples was characterized as excellent or good water quality while 57.5% of the samples had medium water quality, and 32.5% and 10% of the samples exhibited poor and extremely poor water qualities, respectively. The last two categories are designated as unfit for consumption. The cumulative health risk (nitrate and fluoride together) ranged from 0.97 to 11.16 for children, 0.60 to 10.54 for women, and 0.39 to 6.92 for men. These values represent health risks among 88%, 80%, and 73% of the groundwater samples for children, women, and men, respectively. Therefore, proper measures should to be done to reduce the health risks associated with high nitrate and fluoride in the groundwater of the study area, which is used for drinking purposes.
اظهر المزيد [+] اقل [-]Urbanization and carbon emissions: a panel threshold analysis النص الكامل
2021
Khan, Khalid | Su, Chi-Wei
This study analyzes whether an optimal level of urbanization (UB) exists at which the newly industrialized countries (NIC) can reduce carbon dioxide emissions (CE). The results suggest that UB has a positive effect when it is lower than the threshold value. Whereas UB has a negative effect on CE when it is above the threshold value, identify an optimal level in the NIC countries for CE. Moreover, industrialization, economic growth, and energy consumption have a positive significant impact on CE while renewable energy has a negative effect. The study is useful for policymakers to realize optimal UB level to reduce CE. Moreover, the balanced developmental approach for the rural-urban areas and encouragement of internal migration to small cities will minimize the flow of migration to metropolitan cities. Sustainable economic development required continuous energy supply; thus, the event of low carbon energy is extremely vital. The development of low carbon energy is very important and policymakers should improve the structure of energy consumption.
اظهر المزيد [+] اقل [-]Investigating the dynamic relationships between credit supply, economic growth, and the environment: empirical evidence of sub-regional economies in Sub-Saharan Africa النص الكامل
2021
Ntarmah, Albert Henry | Kong, Yusheng | Manu, Emmanuel Kwaku
Sub-Saharan Africa (SSA) is considered the most vulnerable to challenges emanating from climate changes. A number of factors notably accelerated changes in growth influence SSA environment. Linking financial sector within growth and environmental outcomes has been the focus of policy makers and researchers. This study investigated the dynamic relationships between credit supply, economic growth, and the environment from the perspectives of the four sub-regional economies (Central, East, Southern, and West African regions) in SSA over the period 1990–2018. In addition, the study tested Environmental Kuznets Curve hypothesis across sub-regions. We employed panel vector autoregressive (panel VAR) model in a generalized method of moment framework to investigate the topic. The panel VAR results revealed that (i) economic growth negatively influence on carbon emissions of Central African countries but not in the East, Southern and West African sub-regions, (ii) credit supply had significantly positive influence on carbon emissions and economic growth of Central and East African sub-regions but negative influence on carbon emissions and economic growth West African sub-regions in SSA, and (iii) carbon emissions had significantly negatively influence on credit supply of East and West African sub-regions. The granger causality results revealed bidirectional causal links between credit supply and carbon emissions, economic growth, and credit supply in the Central and East African sub-regions, while most of the relationships were unidirectional. The impulse response function revealed that the impact of one variable on another vary throughout the periods and across sub-regions. Similarly, the elasticity of the variables to each other varies across sub-regions over the period studied. EKC hypothesis was validated in East African sub-region but was rejected in Central (u-shape relationship), Southern, and West African sub-regional economies indicating variations in growth and environmental outcomes among the sub-regional economies. Specific sub-regional policy recommendations are discussed.
اظهر المزيد [+] اقل [-]40K, 226Ra, 232Th, 238U and 137Cs relationships and behaviour in sedimentary rocks and sediments of a karstic coastal area (Kaštela Bay, Croatia) and related rocks and sediments’ differentiation النص الكامل
2021
Lovrenčić Mikelić, Ivanka | Oreščanin, Višnja | Barišić, Delko
Natural (⁴⁰K, ²²⁶Ra, ²³²Th, ²³⁸U) and anthropogenic (¹³⁷Cs) radionuclides in consolidated sedimentary rocks (limestones s.l. and marls) and unconsolidated sediments (stream sediments and soils) of the Kaštela Bay (Adriatic Sea, Croatia) coastal area were studied. Kaštela Bay is a typical karstic environment and it is under strong anthropogenic influence due to industrialisation and urbanisation. Relationships between radionuclides, their behaviour in different types of samples and possible influencing factors were studied. Radionuclides were also studied in relation to selected metals (Al, K, Ca, Fe, Ti, Mn, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Pb and As) and distribution in limestones s.l., marls, stream sediments and soils. Radionuclides’ massic activities were determined by gamma-spectrometry and metal mass fractions were measured by EDXRF technique. Relationships were studied using statistical tools (principal component analysis, factor analysis). It was found that stream sediments were more similar to source rocks (limestones s.l. and marl) than to soils in terms of natural radionuclides’ activities. ⁴⁰K and ²³²Th in consolidated rocks were preferentially bound to alumosilicates and associated with the majority of studied metals. However, this was not the case with ²²⁶Ra and ²³⁸U, which did not show any preferences regarding binding to mineral components or associating with metals. On the other hand, all four natural radionuclides presented the same behaviour in unconsolidated sediments, i.e. they were all preferentially bound to alumosilicates and associated with the majority of metals. ¹³⁷Cs did not associate with any of the metals or other radionuclides in sediments. The statistical approach applied in this study revealed differences in radionuclides’ relationships and behaviour in a karstic environment and implied possible influencing processes or factors. This approach can be applied in other types of environments as well to study preferential radionuclides’ binding to certain mineral components that influences radionuclides’ mobility and transport to other environmental compartments.
اظهر المزيد [+] اقل [-]A technological innovation and economic progress enhancement: an assessment of sustainable economic and environmental management النص الكامل
2021
Hao, Wu | Rasul, Farhat | Bhatti, Zobia | Hassan, Muhammad Shahid | Ahmed, Ishtiaq | Asghar, Nabila
This study examines the role of technological innovation and economic progress on environmental pollution by using STRIPAT and EKC theoretical frameworks in 25 developing Asian countries from the period 1998 to 2019. For technological advancement, the energy intensity has been used to gauge how much of the quantity of energy is employed to produce the additional unit of gross domestic product at domestic level. Therefore, the volume of the energy used in the production process is highly important as it is documented through the energy intensity. To capture the impact of innovation, the sum of total patent applications and trademark applications for the sampled countries has been used. This study applied second-generation unit root and panel cointegration techniques to estimate the results. To estimate the long-run relationship of variables and the cross-sectional interdependence, Pedroni Residual and Westerlund Cointegration tests are applied. Further, the Hausman-Taylor-type test has been used to check the efficiency of the pool mean group (PMG). The results of PMG regression confirm the existence of EKC in the developing Asian countries. The results of this study showed that technological development, innovations, and economic progress have the potential to reduce carbon emission and to protect the environment in developing Asian economies. Moreover, the results of error correction model indicate that in case of any external shock, this model will converge towards equilibrium within 64.6 years. The study proposed that a policy framework related to technological innovations should be sustained and the advancement of human capital and research and development should be the primary focus of the developing nations to mitigate the environmental challenges.
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