细化搜索
结果 4491-4500 的 6,535
Numerical simulation and field experiment study on onboard dust removal technology based on airflow–dust pollution dispersion characteristics 全文
2020
Mo, Jinming | Yang, Junlei | Ma, Wei | Chen, Fang | Zhang, Sheji
To solve the problem of dust production by the caving coal seam on the weather side of a fully mechanized coal face with a large mining height, this study proposes coal cutter onboard dust removal technology for the first time. In this work, taking the 12511 fully mechanized coal face of the Bulianta Coal Mine with a large mining height as an example, a mathematical model was built to study the influence of the onboard dust collector on airflow–dust dispersion pollution and the key technological parameters of the dust collector, and field tests were performed for verification. The results of numerical simulation showed that the dust-carrying airflow, after being blocked by the coal cutter, dispersed in the lateral direction, leading to an increase of airflow velocity on the walkway side to 1.75 m s⁻¹, and a dust concentration as high as 2500 mg m⁻³. At the same time, an airflow vortex area with the largest diameter of 3 m was formed near the surface of the coal cutter body, which attracted dust to gather there. However, after the application of the onboard dust removal technology, the lateral dispersion of dust-carrying airflow weakened, and the dust concentration on the walkway side was reduced to below 600 mg m⁻³. In addition, this technology also obviously reduced the influence scope of the vortex and the dust concentration area. It was also found that the installation height of the suction inlet of the dust collector and the air capacity had a large impact on the dust suppression efficiency. The optimum dust suppression efficiency was reached at an installation height of 1.15 m and air capacity of 120 m³ min⁻¹. Field test verification demonstrated that the dust concentration on the walkway side could be reduced by as much as 49.3% with the application of the proposed onboard dust removal technology.
显示更多 [+] 显示较少 [-]Grey water footprint evaluation and driving force analysis of eight economic regions in China 全文
2020
Cui, Shibo | Dong, Huijuan | Wilson, Jeffrey
The grey water footprint (GWF) can be used to connect wastewater quality and quantity, making it a powerful tool for policy makers and those responsible for managing wastewater systems. As a supplementary to existing GWF research, this study explores the GWF evolution of eight economic regions in China by taking into consideration the GWF of livestock feeding. In addition, we use the logarithmic mean division index method to study the background driving forces of GWF in primary industry for eight economic regions. Results show that the overall GWF in China fluctuates from 6082 billion m³ to 6238 billion m³ between the years 2003 and 2015. Primary industry contributes most to the GWF because of livestock feeding, particularly for the northwest economic region, accounting for 84.81% in 2015. The southwest economic region has the highest total GWF, and east coast region has the lowest total GWF. An analysis of driving forces shows that economic scale and industrial structure are the driving forces that best explain the GWF for the East coast, middle of Yellow River, Northwest, and Southwest economic regions. The effects of economic scale and pollution producing intensity are driving the GWF in the Northeast Regions. For the North coast and middle Yangtze River Regions, economic scale, industrial structure, and pollution producing intensity are driving forces for GWF. While for the South coast region, population is an important contributor apart from economic scale and industrial structure. Policy implications from perspective of the agriculture GWF and endowment of different regions were finally discussed.
显示更多 [+] 显示较少 [-]Acute oral toxicity study on Wistar rats fed microalgal protein hydrolysates from Bellerochea malleus 全文
2020
Barkia, Ines | Ketata Bouaziz, Hanen | Sellami Boudawara, Tahiya | Aleya, Lotfi | Gargouri, Ali Faouzi | Saari, Nazamid
Protein hydrolysates and bioactive peptides from various protein sources have demonstrated their effectiveness for the prevention of illness and the improvement of symptoms from several diseases. In particular, the use of microalgae to generate bioactive peptides has received a growing interest because of their potential to be cultivated on non-arable land and high nutritional value. However, scant research is available on the toxicity of peptide-based preparations. The present study aims to evaluate the toxicity of microalgal protein hydrolysates (MPH) from one marine species of microalgae (Bellerochea malleus) to determine the feasibility of their use for functional food applications. Results showed that the oral administration of MPH at three doses (D1, 100 mg kg⁻¹ BW; D2, 400 mg kg⁻¹ BW; and D3, 2000 mg kg⁻¹ BW) to male Wistar rats did not induce any adverse effects or mortality up to13 days of treatment. Data analysis of relative organ weights and biochemical and hematological parameters did not show any significant differences between control and treated groups at the three doses investigated. Data from histopathological observations did not reveal any signs of major toxicity at the doses D1 and D2. However, mild signs of inflammation and necrosis were observed in the kidney of rats fed MPH at D3. All together, these results reveal the overall safety of MPH and provide new evidence for advocating their use for functional food or nutraceutical applications.
显示更多 [+] 显示较少 [-]Sustainability and CDM potential analysis of a novel vs conventional bioenergy projects in South Asia by multi-criteria decision-making method 全文
2020
Rasheed, Rizwan | Javed, Hajra | Rizwan, Asfra | Yasar, Abdullah | Tabinda, Amtul Bari | Mahfooz, Yusra | Wang, Yubo | Su, Yuehong
In this study, the multi-attribute utility theory model, one of the most widely utilized multi-criteria decision-making methods, is employed to analyze the relative sustainability and cleaner development mechanism (CDM) potential of a novel bioenergy project in Pakistan and four registered CDM bioenergy installations in China, India, Sri Lanka, and Thailand. Four major sustainability evaluation criteria selected for the study are technology, economy, environment, and social aspects, whereas “simple multi-attribute rating technique” (SMART) and “additive synthesis method” were utilized for the calculation of weighting factors. The most significant indicator was emission reduction, and least significant indicator was job creation with 24% and 15% respective weightages, in the sustainability scoring. Moreover, for three considered evaluation scenarios, (I) base case, (II) per kilowatt, and (III) per kilowatt hour, the bioenergy project in Pakistan has the highest comparative sustainability values of 0.735, 0.592, and 0.492 respectively. This analysis will provide an insight assistance to developing countries for establishing sustainable energy installations under CDM.
显示更多 [+] 显示较少 [-]Concentrations, distributions, sources, and risk assessment of polycyclic aromatic hydrocarbons in topsoils around a petrochemical industrial area in Algiers (Algeria) 全文
2020
Benlaribi, Rabia | Djebbar, Safia
Fifty-five samples were collected from topsoils around a petrochemical industrial area at the east of Algiers (Algeria) and analyzed for 16EPA priority PAHs in the aim to determine the concentrations, the distributions, and the possible sources of polycyclic aromatic hydrocarbons (PAHs). The results of the quantification are then devoted to the assessment of the potential risks as the toxicity, the risk for the ecosystem, and the risk for the human health. The sampling sites were classified into four categories: rural, suburban, urban, and industrial-urban. A new extraction method based on the insertion of a preliminary step, using hot water, was proposed to improve the extraction efficiency. Principal component analysis (PCA) and selected diagnostic ratio of PAHs were used to investigate the source apportionment of these PAHs. The potential toxicity, the ecological, and human health risk of PAHs in soil were estimated using the toxic equivalent quotient, the risk quotient, and the total lifetime cancer risk (TLCR) methods, respectively. The proposed new protocol gave improved recovery rates for the sixteen EPA PAHs particularly for low molecular weight PAHs, with satisfactory repeatability (RSD < 10%). The Σ16PAHs concentrations were varied from 143.73 to 4575.65 μg kg⁻¹ with a mean value of 1209.56 μg kg⁻¹. Σ16PAH concentrations found for the industrial areas would be 2 times higher than for urban soils and 3 times higher than for the rural soils. The biplots of PCA and the five diagnostic ratios suggested that the most sources of PAHs in the rural, the suburban, and the urban areas are traffic emissions, biomass burning, and coal combustion sources. Some points of the urban-industrial area are from the petroleum source. The found Σ16PAH concentrations and theirs calculated TEQs showed the following trend: industrial-urban > urban > suburban >rural. The potential cancer of human health risks calculated through TLCR results indicated that the exposure to the 7EPA PAH-contaminated soils produces negligible cancer risk to human health.
显示更多 [+] 显示较少 [-]Study on industrial selection of counterpart cooperation between Jilin province and Zhejiang province in China from the perspective of low carbon 全文
2020
Li, Dongrui | Lei, Yalin | Li, Li | Liu, Lingna
Counterpart cooperation is a major innovative measure in China’s strategy for revitalizing north-eastern China. While promoting economic progress, regional counterpart cooperation should also focus on low-carbon economy and sustainable development. Under the background of China’s proposed innovative cooperation strategy, using a multi-regional input-output (MRIO) model and structural decomposition analysis (SDA), this study takes Jilin province and its counterpart Zhejiang province as an example and decomposes the change in carbon emission intensity (CEI), which is a widely used indicator to measure regional carbon emission performance. The decomposition spans the years 2007 to 2012, at the level of two provinces and departments. By comparing the factors that drive and inhibit CEI in the two provinces, it was found that the production technology effect in Jilin province primarily drove the growth in CEI, while in Zhejiang province, the opposite occurred. Second, the structural effects of agriculture and heavy industry in Jilin province accounted for the largest proportion of this change, and the pulling effect on the increase in CEI in Jilin was significantly higher than that in Zhejiang province. Third, the scale effect of agricultural demand in Zhejiang province was much higher than that in Jilin province, and the same trend was observed for the scale effect of heavy industrial exports.
显示更多 [+] 显示较少 [-]Oxidative stress, biochemical, lipid peroxidation, and antioxidant responses in Clarias gariepinus exposed to acute concentrations of ivermectin 全文
2020
Ogueji, Emmanuel | Nwani, Christopher | Mbah, Christian | Iheanacho, Stanley | Nweke, Friday
The short-term effects of ivermectin (IVMT) on the oxidative stress and biochemical parameters of Clarias gariepinus juvenile was assessed under semi-static conditions at concentrations of 9 to 25 μg L⁻¹ for up to 4 days. Juveniles were highly sensitive to ivermectin, with an LC₅₀ of 15 μg L⁻¹.The antioxidant enzyme profile assessed included glutathione reductase (GR), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT). General stress biomarkers such as serum glucose, protein, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were also determined at 24-h, 48-h, 72-h, and 96-h exposure durations. Lipid peroxidation showed significant (p < 0.05) decreases in higher concentrations (21 μg L⁻¹and 25 μg L⁻¹) and durations of exposure (72 h and 96 h). Significant concentration-dependent increases (p < 0.05) were recorded in the liver function enzymes, superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR) when compared to the control. GPx decreased significantly (p < 0.05) in higher concentrations (21 μg L⁻¹and 25 μg L⁻¹) and durations of exposure (48–96 h). Protein showed significant concentration-dependent decreases, while glucose recorded a mixed trend. The changes in the hepatic antioxidant enzyme activities and serum metabolites were indicative of oxidative stress induced by IVMT. This showed that IVMT is toxic to fish and should be used with utmost caution.
显示更多 [+] 显示较少 [-]An environmentally friendly strategy for determining organic ultraviolet filters in seawater using liquid-phase microextraction with liquid chromatography–tandem mass spectrometry 全文
2020
Ku, Ping-Chang | Liu, Ting-Yu | Lee, Shu Hui | Kung, Te-An | Wang, Wei-Hsien
Benzophenone-3, benzophenone-8, and 4-methylbenzylidene camphor are used in sunscreens because they can protect the skin from UV radiation. The widespread use of organic UV filters may mean that they directly or indirectly enter seawater during recreational activities or through sewage discharge. In this study, a simple and efficient method using 1-octanol:isooctane (2:8, v/v) as an extraction solvent and liquid chromatography–electrospray tandem mass spectrometry was developed to measure trace levels of organic UV filters in seawater samples. This proposed method proved to be a highly sensitive, low-cost, and green analytical tool that requires minimal sample preparation. The method was validated and it exhibited favorable performance as well as acceptable accuracy (67 to 115%), precision (2.1 to 7.3%), coefficients of determination (0.9952 < R² < 0.9987), sensitivity (limits of quantification [3.3 to 5.7 ng L⁻¹]), and an acceptable matrix effect (87 to 99%). This methodology was successfully applied to analyze seawater taken from Kenting National Park located in the Hengchun Peninsula of southern Taiwan. Benzophenone-3 was detected at all sampling sites and at a higher concentration than the other organic UV filters. The highest concentration of benzophenone-3 was 514.6 ng L⁻¹ in a sample collected from Baisha Beach.
显示更多 [+] 显示较少 [-]Qualitative and quantitative analysis of municipal solid waste in Iran for implementation of best waste management practice: a systematic review and meta-analysis 全文
2020
Kamarehie, Bahram | Jafari, Ali | Ghaderpoori, Mansour | Azimi, Faramarz | Faridan, Mohammad | Sharafi, Kiomars | Ahmadi, Fatemeh | Karami, Mohammad Amin
With the rapid growth of population, development of different industries, and production of several ranges of products, the generation of municipal solid waste (MSW) has been growing significantly in the recent years. However, if MSW is not managed properly, it can greatly contribute to an environmental crisis. In the present study, we aimed to examine the characteristics and quantity of MSW generated in Iran through a meta-analysis and systematic review. The major international and Iranian national databases including Science direct, Scopus, PubMed, Google scholar, and SID and Magiran were searched completely using appropriate keywords to identify the articles that have been published from 2003 up to November 2019 on the topic on interest. Based on the inclusion criteria, a number of 13 papers were found eligible to be reviewed in this study. The results showed that the amount of generated waste per capita in Iran is 839 g/capita/day. Moreover, organic matters, paper and cardboard, plastics, glasses, textiles, rubber, polyethylene terephthalate (PET), metals (ferrous and non-ferrous), wood materials, and other wastes were found to be contributed to 65.85%, 8.79%, 8.39%, 2.73%, 2.74%, 1.18%, 1.07%, 2.83%, 1.20%, and 5.22% of total MSW in Iran, respectively. Due to the high level of organic waste in MSW stream in Iran, composting program is recommended as a practical and beneficial approach. Of note, the recyclable materials include plastic, PET, glass, metals, and paper and cardboard have accounted for 24.05% of total MSW in Iran.
显示更多 [+] 显示较少 [-]Ameliorative effect of curcumin against lead acetate–induced hemato-biochemical alterations, hepatotoxicity, and testicular oxidative damage in rats 全文
2020
Abdelhamid, Fatma M. | Mahgoub, Hebatallah A. | Ateya, Ahmed I.
Lead, toxic heavy metal of global concern, induces toxicity in various organs via oxidative stress. Thereby, in this study, the protective role of curcumin against lead acetate-induced toxicity was evaluated. Thirty-two male albino rats were allocated equally into four groups and orally administered with corn oil as a vehicle (Cont.), curcumin (CUR) (400 mg/kg bw), lead acetate (LA) (100 mg/kg bw), and lead acetate plus curcumin (LA + CUR). All rats had received their treatments daily for 4 weeks. The results revealed that LA toxicity induced normocytic normochromic anemia with significant leukocytosis and lymphocytosis. Moreover, LA-intoxicated rats showed a marked elevation in the liver enzyme activities, serum cholesterol, and triglyceride levels. In contrast, sero-immunological parameters, total protein, albumin, globulin, and testosterone levels were significantly reduced compared to the control rats. Additionally, LA-induced hepatic and testicular oxidative damage revealed by marked increased in MDA level with prominent reduction in the antioxidant system. The gene expression of the hepatic pro-inflammatory markers and testicular steroidogenic biomarkers including LHR and aromatase were significantly upregulated; meanwhile, the expressions of testicular StAR, CYP17a, 3B-HDS, SR-B1, and P450SCC were significantly downregulated in the LA-intoxicated group. Curcumin treatment could partially improve the hematological, biochemical, and histopathological alterations induced by LA. Also, it was observed that curcumin significantly restored hepatic pro-inflammatory markers and testicular steroidogenic enzymes. In conclusion, curcumin has antioxidant, anti-inflammatory, and immunomodulatory effects and is able to minimize the LA-induced oxidative damage in rats.
显示更多 [+] 显示较少 [-]