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Elemental composition of three-spot swimming crab Portunus sanguinolentus (Herbst, 1783) shell from the coasts of Sindh and Balochistan, Pakistan 全文
2022
Hassan, Habib Ul | Razzaq, Wajeeha | Masood, Zubia
The present study aimed to investigate the elemental composition of the hard shell of the three-spot swimming crab, Portunus sanguinolentus, collected from the coasts of Pakistan. Thirty crab shells were collected and divided into three groups considering their size. The element detection was performed by energy-dispersive X-ray spectroscopy with scanning electron microscope (SIM/EDAX). The mean concentration of carbon, oxygen, calcium, copper, magnesium, and phosphorus observed in the shell of P. sanguinolentus was 13.63 ± 6.21%, 46.25 ± 12.62%, 34.39 ± 18.33%, 3.19 ± 1.25%, 1.15 ± 0.99%, and 1.39 ± 0.51%, respectively. The concentration pattern of these observed elements in P. sanguinolentus shells was found in the following order: O > Ca > C > Cu > P > Mg. To compare among the three groups of shells, the highest concentration of calcium (54.60%) was obtained in large-sized shell groups, which was significantly different from the other groups (p < 0.05). A high concentration of copper was found to be accumulated in the large-sized (3.55%) and medium-sized (4.21%) shell groups, which was significantly higher than in small-sized shell groups (p < 0.05). In the case of the large-sized shell group, the mean concentrations of magnesium and phosphorus were significantly lower than the medium-sized shell group (p < 0.05). The results indicate that crab shells could act as a good bio-sorbent for several minerals in its ecosystem. P. sanguinolentus shell is very rich in calcium, magnesium, and phosphorus. Extraction of calcium, magnesium, and phosphorus from P. sanguinolentus shells could be profitable for biofertilizer and pharmaceutical industries.
显示更多 [+] 显示较少 [-]Do entrepreneurial orientation and intellectual capital influence SMEs’ growth? Evidence from Pakistan 全文
2022
Abbas, Muhammad Ghazanfar | Wang, Zhuquan | Ullah, Hafeez | Mohsin, Muhammad | Abbas, Hasnain | Mahmood, Memon Rafait
This research analyzes the impacts of intellectual capital (IC) and the balancing power of entrepreneurial orientation (EO) on innovation growth (IG) in Pakistan’s SME sector. A quantitative approach on smart PLS has been applied through the SEM model, backed by a survey to gather primary data from 256 participants of Pakistan’s SME sector. A significant effect of human capital on Pakistani firms’ IG was identified. In contrast, the effect of structural capital was determined to be insignificant over the IG of Pakistani firms. On the other hand, the customer capital’s effect was also significant over Pakistani firms’ innovation growth. Little moderation of EO between human capital and IG has been determined. The moderations of “EO between human capital and innovation growth” and “EO between structural capital and innovation growth” were insignificant. However, the moderation of EO between customer capital and IG was significant. The scope of this study is limited to firms in Pakistan and can be extended to firms in other regions, which can provide broad findings.
显示更多 [+] 显示较少 [-]Catalytic activity of Cu/η-Al2O3 catalysts prepared from aluminum scraps in the NH3-SCO and in the NH3-SCR of NO 全文
2022
Jraba, Nawel | Makhlouf, Thabet | Delahay, Gerard | Tounsi, Hassib
Copper-loaded η-alumina catalysts with different copper contents were prepared by impregnation/evaporation method. The catalysts were characterized by XRD, FTIR, BET, UV-Vis, and H₂-TPR and evaluated, for the first time, in the selective catalytic reduction of NO by NH₃ and in the selective catalytic oxidation of NH₃. The characterization techniques showed that the impregnation/evaporation method permits to obtain highly dispersed copper oxide species on the η-alumina surface when a low amount of copper is used (1wt. % and 2 wt.%). The wet impregnation method made it possible to reach a well dispersion of the copper species on the surface of the alumina for the low copper contents Cu(1)-Al₂O₃ and Cu(2)-Al₂O₃. The latter justifies the similar behavior of Cu(1)-Al₂O₃) and Cu(2)-Al₂O₃ in the selective catalytic oxidation of NH₃ where these catalysts exhibit a conversion of NH₃ to N₂ of the order of 100% at T> 500 °C.
显示更多 [+] 显示较少 [-]Chemical remediation and advanced oxidation process of polychlorinated biphenyls in contaminated soils: a review 全文
2022
Hashmi, Muhammad Zaffar | Kalīm, Muḥammad | Farooq, Umar | Su, Xiaomei | Chakraborty, Paromita | Rehman, Shams Ur
Polychlorinated biphenyls (PCBs) are synthetic organic compounds ubiquitously distributed worldwide due to their persistence, long-range atmospheric transport, and bioaccumulation. Owing to teratogenic properties, PCBs are a global environmental problem. Different physical, biological, and chemical techniques are utilized for the remediation of PCBs. This review paper discusses the recent development in photocatalytic and chemical techniques for the remediation of PCBs in contaminated soils. In particular, the photocatalytic degradation of PCBs combined with soil washing, Fe-based reductive dichlorination, and advanced oxidation process (Fenton advance oxidation and persulfate oxidation) is discussed and reviewed in detail. The review suggested that advanced oxidation is an efficient remediation technique with 77–99% of removal efficiency of PCBs. Persulfate oxidation is the most suitable technique which could work at normal environmental conditions (such as pH, temperature, soil organic matter (SOM), etc.). Different environmental factors such as pH, temperature, and SOM affect the Fe-based reductive dechlorination and Fenton advance oxidation techniques. The surfactants and organic solvents used in soil washing combined with photocatalytic degradation affect the degradation capability of these techniques. This review will contribute to PCBs degradation by the detailed discussion of development in chemical technique future perspective and research needs.
显示更多 [+] 显示较少 [-]Environmental downfall in Bangladesh: revealing the asymmetric effectiveness of remittance inflow in the presence of foreign aid 全文
2022
Kibria, Md Golam
Even though remittance inflow in Bangladesh is a significant earning source for recipient individuals and one of the vital factors to the development model, its environmental impacts have been ignored in the empirical investigation. To fill this research gap, this article aims to elucidate the asymmetric effectiveness of remittance inflow on environmental degradation in Bangladesh by addressing foreign aid as an additional multiplier in a carbon dioxide (CO₂) emissions model, a first for this country. This paper, in doing so, utilizes the newly advanced nonlinear autoregressive distributive lag (NARDL) approach. Data examined are yearly observations throughout 1980–2016, and empirically, the results of the NARDL bound test confirm a long-run cointegrated causality between remittance and CO₂ emissions via approving the theoretical linkage. The asymmetric findings interpret that the intensity of CO₂ emissions raises in the long run relative to the positive shock in remittance, while the elasticity of CO₂ emissions is significant and negative due to the negative shock in remittance. The estimation also reveals the presence of a long-run asymmetric association between the variables. In addition, foreign aid is favorable to ameliorate the quality of the environment over a long period. Focusing on the findings, this paper recommends that the government should concentrate on environment favorable projects and also take measures of tax incentives to remittance investors.
显示更多 [+] 显示较少 [-]Human induced fish declines in North America, how do agricultural pesticides compare to other drivers? 全文
2022
Brain, Richard Aaron | Prosser, Ryan Scott
Numerous anthropogenic factors, historical and contemporary, have contributed to declines in the abundance and diversity of freshwater fishes in North America. When Europeans first set foot on this continent some five hundred years ago, the environment was ineradicably changed. Settlers brought with them diseases, animals, and plants via the Columbian Exchange, from the old world to the new, facilitating a process of biological globalization. Invasive species were thus introduced into the Americas, displacing native inhabitants. Timber was felled for ship building and provisioning for agriculture, resulting in a mass land conversion for the purposes of crop cultivation. As European colonization expanded, landscapes were further modified to mitigate against floods and droughts via the building of dams and levees. Resources have been exploited, and native populations have been overfished to the point of collapse. The resultant population explosion has also resulted in wide-spread pollution of aquatic resources, particularly following the industrial and agricultural revolutions. Collectively, these activities have influenced the climate and the climate, in turn, has exacerbated the effects of these activities. Thus, the anthropogenic fingerprints are undeniable, but relatively speaking, which of these transformative factors has contributed most significantly to the decline of freshwater fishes in North America? This manuscript attempts to address this question by comparing and contrasting the preeminent drivers contributing to freshwater fish declines in this region in order to provide context and perspective. Ultimately, an evaluation of the available data makes clear that habitat loss, obstruction of streams and rivers, invasive species, overexploitation, and eutrophication are the most important drivers contributing to freshwater fish declines in North America. However, pesticides remain a dominant causal narrative in the popular media, despite technological advancements in pesticide development and regulation. Transitioning from organochlorines to organophosphates/carbamates, to pyrethroids and ultimately to the neonicotinoids, toxicity and bioaccumulation potential of pesticides have all steadily decreased over time. Concomitantly, regulatory frameworks designed to assess corresponding pesticide risks in Canada and the USA have become increasingly more stringent and intensive. Yet, comparatively, habitat loss continues unabated as agricultural land is ceded to the frontier of urban development, globalized commerce continues to introduce invasive species into North America, permanent barriers in the form of dams and levees remain intact, fish are still being extracted from native habitats (commercially and otherwise), and the climate continues to change. How then should we make sense of all these contributing factors? Here, we attempt to address this issue.
显示更多 [+] 显示较少 [-]Applications of waste-derived visibly active Fe-TiO2 composite incorporating the hybrid process of photocatalysis and photo-Fenton for the inactivation of E. coli 全文
2022
Thakur, Ina | Verma, Anoop | Örmeci, Banu | Sangal, Vikas
The study reports the applications of waste-derived visibly active Fe-TiO₂ composite for the inactivation of E. coli present in water. The Fe/TiO₂ catalyst holds remarkable properties of in situ hybrid effect via combining the TiO₂-photocatalytic and photo-Fenton process in one system causing increased production of OH˚. The quantum yield (QY) and reaction rate constant of this hybrid process at 40 W m⁻² (UV-A irradiation) were found to be significantly higher in less treatment time (45 min) of E. coli inactivation. 23% synergy of in situ hybrid process over single processes was also observed. The increase in the K⁺ concentration at regular intervals confirmed the cell wall damage. In fully inactivated samples, no regrowth of cells was observed even after 24 and 48 h of dark study. Additionally, even after 100 recycles, the Fe/TiO₂ catalyst demonstrated an exceptional durability/recyclability efficacy. The findings of this study highlight the potential of the hybrid process as a viable idea for post-treatment of the wastewater that can be implemented effectively in practice.
显示更多 [+] 显示较少 [-]Are electric vehicles cost competitive? A case study for China based on a lifecycle assessment 全文
2022
Yang, Lai | Yu, Biying | Malima, Gabriel | Yang, Bo | Chen, Hao | Wei, Yiming
Promoting the development of electric vehicles (EVs) is regarded as an important measure to ensure energy security, mitigate climate change, and solve the transport sector’s air pollution problems. Nowadays, compared to gasoline vehicles, whether the EVs are more competitive in terms of cost is still a question. There is no consensus achieved since the total cost depends on the development stage of the automobile industry and power generation structure as well as the cost accounting boundary. Many of existing studies did not include the costs occurred in all the stages. In response to this concern, this study estimates the lifecycle cost covering the whole process of production, use, disposal, and infrastructure construction as well as externalities for passenger battery electric vehicle (BEV), fuel cell vehicle (FCV), and gasoline vehicle (GV) by applying the comprehensive lifecycle cost model to China. The results indicate that in 2018, BEV and FCV were more expensive than GV (1.2–5.3 times), but that BEV will become cheaper after 2025, and its cost advantage will be enlarged to $419 (5%) compared to GV by 2030. The lifecycle cost of FCV will be $527 (or 5%) lower than that of GV by 2030. These results clarify that the costs of vehicle production account for the largest proportion in the total lifecycle cost.
显示更多 [+] 显示较少 [-]Does industrial agglomeration affect the regional environment? Evidence from Chinese cities 全文
2022
Hao, Yu | Song, Jingyang | Shen, Zhiyang
This study examines the impact of industrial agglomeration on the regional environment using panel data of 13 prefecture-level cities in the Beijing-Tianjin-Hebei region from 1998 to 2018. The empirical results show a strong spatial autocorrelation and a strong spatial lag and spatial error effect on the environmental pollution level in the Beijing-Tianjin-Hebei region. The results further show that the manufacturing agglomeration significantly aggravates the regional pollution; service agglomeration significantly alleviates the regional environmental pollution; the synergistic agglomeration of manufacturing and service industry has a significant inverted “U” type relationship on the regional environmental pollution. More specifically, the development of synergistic agglomeration intensifies regional environmental pollution at the early stage, and after reaching the inflection point, synergistic agglomeration alleviates regional environmental pollution. The inflection point occurs when the level of synergistic agglomeration is around 2.85. At the same time, there is no significant spillover effect of synergistic agglomeration on neighboring regions after calculating the feedback effect. Study findings provide insights for promoting the strategy of “two-wheel-drive development” and alleviating the contradictory relationship between industrial development and environmental pollution.
显示更多 [+] 显示较少 [-]Comparison of metal burden in different muscle tissues of Great cormorant (Phalacrocorax carbo) 全文
2022
Lehel, József | Grúz, Adrienn | Bartha, András | Pintér, Imre | Lénárt, Zoltán | Major, László | Menyhárt, László | Szabó, Rita | Budai, Péter
Concentrations of 12 metals (As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb and Zn) were examined in the pectoral and thigh muscle of great cormorants (Phalacrocorax carbo). The samples were collected from Central Tisza-Jászság Nature Conservation Area in Hungary. The tissue samples were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The aim of the study was to examine the impacts of heavy metal pollution on the water birds, determine the concentrations of the abovementioned metals in the different muscle tissues of these wetland birds, and provide the basic materials for monitoring the environmental pollution. Among the investigated elements/metals, the detected concentrations of As, Ba, Cd, Co, Cr, Mo and Ni were below the detection limit. Higher concentration of Cu, Hg, Mn and Pb was measured in the pectoral muscle compared to the thigh muscle, but only in the case of Cu and Mn were found significant differences between the tissues. In the case of the Zn concentration, the higher value was detected in the thigh muscle. There were no statistical differences between males and females in either metal concentrations.
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