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Hydraulic Performance and Energy Loss Effect of Pit Structure Optimized Drip Irrigation Emitter
2022
Tianyu Xu, Shuteng Zhi, Qiuyue Yu | Ennan Zheng
The pit structure optimized drip irrigation emitter (PODE) is a novel type of irrigation emitter that may provide shunts, quick diversion, and mixed flow to maximize energy loss. To study the influence of the geometric parameters of the flow channel on the hydraulic characteristics and energy loss effect, twenty-five sets of orthogonal test schemes were established. Using numerical simulation and verification tests, the flow index and energy loss coefficient were obtained. The results showed that the flow index of the PODE was 0.4632-0.5265, and its hydraulic performance was good. The energy loss coefficient under the pressure head of 5-15 m was 510-2221, which showed that the energy loss effect was obvious. The influence order of the geometric parameters on the flow index was B>P>C>D>A, the optimal solution was P0.6D1.4A85B0.25C0.12. The determination coefficient of the regression model based on geometric parameters and flow index was 0.85. In addition, the verification test showed that the relative error among the test value, simulated value, and estimated value were less than 5%, and the flow index can be estimated reliably. The research can provide a reference for the pre-research and evaluation of the hydraulic performance and energy loss effect of the PODE.
Mostrar más [+] Menos [-]Preparation of Silver and Copper Co-impregnated Nano-ZnO Immobilized on Mesoporous SiO2 and its Photocatalytic Performance
2022
Qinlin Yuan, Hang Xu, Shaokang Wang, Zhewen Yang, Wenke Zhang | Qinggao Ma
To improve light usage, Ag and Cu were co-impregnated with nano-ZnO, and the mesoporous silica gel (meso-SiO2) was chosen as the carrier. The sol-gel method was used to successfully construct a composite photocatalyst with 3 percent Ag/0.1 percent Cu/nano-ZnO/meso-SiO2. For the evaluation of the photocatalytic activity of the as-prepared catalysts, Reactive Black 5 was used as a simulated organic pollutant in aqueous. The results revealed that uniform spherical nano-ZnO particles with a diameter of 10 nm were attached to the surface and mesopore of meso-SiO2. The average pore width and specific surface area of this composite were 7.06 nm and 305 m2.g-1, respectively. The optimal amount of loaded Ag and Cu were 3% and 0.1%, respectively, which resulted in around 100% removal of Reactive Black 5 after 280 min UV-light irradiation. The degradation process followed pseudo-first-order kinetics. Ag and Cu-loaded nano-ZnO/SiO2 could be advantageous for suppressing the recombination of photo-generated holes and electrons, thus improving the degradation efficiency. The constant of degradation rate and adsorption equilibrium of 3%Ag/0.1%Cu/nano-ZnO/meso-SiO2 were 0.049 min–1 and 2.14 L.g-1, respectively. After three reuses, the Ag/Cu/ZnO/meso-SiO2 photocatalyst remained very stable during the photocatalytic process with no loss of photocatalytic activity. According to the GC-MS results, a probable degradation mechanism was estimated.
Mostrar más [+] Menos [-]Study on Spatiotemporal Characteristics of the Impacting Factors of Agricultural Carbon Emissions Based on the GTWR Model: Evidence from the Yellow River Basin, China
2022
Haifeng Huang | Ni Zhu
Scholars have turned their attention to the ecological protection and high-quality development of China’s Yellow River Basin in recent years. The basin is a major agricultural production area in China, hence investigating agricultural carbon emission reduction strategies in the basin is crucial. The research object in this article is the agricultural departmen.ts of China’s nine provinces in the Yellow River Basin from 2005 to 2018. Agricultural carbon emissions are measured using agricultural land usage, rice planting, crop planting, straw burning, and livestock breeding as agricultural carbon sources. In addition, the GTWR model is used to examine the spatiotemporal aspects of the impact of five factors on agricultural carbon emissions in this paper. The findings reveal that the five factors have varying degrees and directions of influence.
Mostrar más [+] Menos [-]Towards a Framework for Sustainable Municipal Solid Waste Management: The Case of Swakopmund Municipality, Namibia
2022
Timoteus Kadhila | Martin P. de Wit
If municipal solid waste (MSW) is not properly managed, harmful environmental consequences are imminent. MSW materials are rarely wasted in many affluent countries, but rather are kept in the economic cycle through circular economy models. While in many developing countries, MSW materials are discarded with little to no effort of repairing or recycling. Moving to a circular economy will drastically reduce the amount of waste currently disposed of. This study examines how the Swakopmund Municipality in Namibia’s present municipal solid waste management techniques could be adjusted toward sustainability to reap environmental and socioeconomic benefits from the trash. Source reduction, separation at source, and recycling are some of the most effective strategies in the circular economy models that will help achieve the United Nations (UN) Sustainable Development Goals (SDGs). Swakopmund Municipality should invest in infrastructure, techniques, and programs that are within the circular economy model as an emerging system for sustainability.
Mostrar más [+] Menos [-]Delineation of Groundwater, Drought and Flood Potential Zone Using Weighted Index Overlay Analysis and GIS for District Patna, Bihar, India
2022
Nikhilesh Gaurav | Geeta Singh
For groundwater evaluation, delineation, discovery, and resource management in drought and flood zones, the geographical information system (GIS) has a wide range of uses. For the study area, various thematic layers were prepared, such as a digital elevation map (DEM), geomorphology, LULC, soil, drainage density, precipitation, and slope. The thematic layers were combined using the WIOA technique. The possible areas for groundwater have been demarcated into four zones: 1-poor, 2-moderate, 3-good, and 4-very good. In the eastern parts of the district, very strong (GWPZs) were found, while in the west and mid regions, moderate and bad categories were found. Drought and flood potential danger areas were divided into four zones: 1-no risk, 2-low risk, 3-moderate risk, and 4-high risk. In the middle part of the region, there was a higher risk of drought and a reduced risk of flooding in the eastern part of the area, an elevated risk of flooding in the eastern part of the area, and a lower to no risk of flooding in the western and central regions. The groundwater, drought, and flood potential zonation map built in the present study will be useful for scholars, and implementers in exploring appropriate water exploration locations and implementing resource utilization.
Mostrar más [+] Menos [-]Elimination of Greenhouse Gas Emissions by Utilization of Industrial Wastes in High Strength Concrete for Environmental Protection
2022
R. Divahar, K. Naveen Kumar, P. S. Aravind Raj | S. P. Sangeetha
Greenhouse gases prevalence in the atmosphere is a primary reason for global warming. The cement manufacturing sectors are a significant producer of greenhouse gases, contributing one metric tonne of carbon dioxide into the environment for every metric tonne of cement produced. The heat of concrete is increased by several degrees during the pozzolanic reaction, and CO2 is released. The development of binary and ternary cementitious systems has minimized the unfavorable reactions of conventional cementitious materials. Metakaolin and alccofine, two mineral admixtures derived as waste products from industries, were used as cement substitutes in this study. The compressive strength of alccofine was compared to a metakaolin-based high strength eco-friendly concrete mix of grade M50 in an experimental investigation. In the case of binary and ternary blended cementitious systems with alccofine and metakaolin, twelve alternative mix proportions were tested, ranging from 0 to 20% in 5% increments. Based on the observed mechanical characteristics of concrete, it was discovered that the optimum replacement of alccofine was 15% and metakaolin was 5% by volume of cement in the binary cementitious system. Similarly, in the ternary cementitious system, replacing 15% alccofine with 5% metakaolin in the cement mixture results in the greatest increase in compressive strength when compared to the other experiments. As a result, it is concluded that using extra cementitious materials in concrete with mineral admixtures such as alccofine and metakaolin results in significant cost and energy savings, as well as a notable reduction in environmental pollution.
Mostrar más [+] Menos [-]Interpretive Structural Modelling (ISM) of Enablers Affecting Green Accounting in Indian Manufacturing Sector: A Conceptual Model
2022
Anjali Singh, Archana Singh | Biju G. Pillai
Green accounting is vital for every economy in the world. Indian manufacturing sectors are regarded as one of the most significant contributors to environmental and socioeconomic problems, and as a result, the country lacks global sustainability and progress. This paper focuses on how these industries can contribute to the sustainability of the environment. The paper aims to analyze how these industries can promote ecopreneurial behavior. Also, the researchers and expert opinions lead to a theoretical framework and conceptual model using a well-defined and explained literature review and the derived model to understand, observe, and analyze various environment awareness concerns. To gather the expert opinions, various calls and surveys were scheduled with chartered accountants, academicians, environmental experts, commerce people, to understand how the identified variables are influenced by each other. Environmental management accounting and green accounting came out as the most significant and vital factors. All the identified variables were complementing. Three levels came out for the model. The authors created an ISM on factors affecting green accounting in the Indian manufacturing sector, emphasizing the context and concept related to the discovered variables that have been tested in the real world.
Mostrar más [+] Menos [-]The role of mesopelagic fishes as microplastics vectors across the deep-sea layers from the Southwestern Tropical Atlantic
2022
Justino, Anne K.s. | Ferreira, Guilherme V.b. | Schmidt, Natascha | Eduardo, Leandro N. | Fauvelle, Vincent | Lenoble, Véronique | Sempéré, Richard | Panagiotopoulos, Christos | Mincarone, Michael M. | Frédou, Thierry | Lucena-frédou, Flávia
Microplastics (MPs; <5 mm) are a macro issue recognised worldwide as a threat to biodiversity and ecosystems. Widely distributed in marine ecosystems, MPs have already been found in the deep-sea environment. However, there is little information on ecological mechanisms driving MP uptake by deep-sea species. For the first time, this study generates data on MP contamination in mesopelagic fishes from the Southwestern Tropical Atlantic (SWTA) to help understand the deep-sea contamination patterns. An alkaline digestion protocol was applied to extract MPs from the digestive tract of four mesopelagic fish species: Argyropelecus sladeni, Sternoptyx diaphana (Sternoptychidae), Diaphus brachycephalus, and Hygophum taaningi (Myctophidae). A total of 213 particles were recovered from 170 specimens, and MPs were found in 67% of the specimens. Fibres were the most common shape found in all species, whereas polyamide, polyethylene, and polyethylene terephthalate were the most frequent polymers. The most contaminated species was A. sladeni (93%), and the least contaminated was S. diaphana (45%). Interestingly, individuals caught in the lower mesopelagic zone (500–1000 m depth) were less contaminated with MPs than those captured in the upper mesopelagic layer (200–500 m). Our results highlight significant contamination levels and reveal the influence of mesopelagic fishes on MPs transport in the deep waters of the SWTA.
Mostrar más [+] Menos [-]Delineation of Groundwater Salinity Zones in Shefa and Malampa Provinces, Vanuatu
2022
K. K. Kotra, S. Bathula | E. Sami
A preliminary assessment was carried out in identifying the salinity zones due to considerable concern over salty groundwater resources in Vanuatu’s Shefa and Malampa regions. Electrical conductivity (EC) and pH were measured on the islands of Efate, Lamen, and Nguna in Shefa province, as well as the islands of Ambrym and Paama in Malampa province. Thirty-four percent of the samples exceeded Vanuatu’s National Drinking Water Standards with an average of 3123 μS/Cm indicating possible salinity zones. Whereas the average pH of 7.21 was in the range of acceptable levels. EC values as high as 18,520 μS/cm indicate groundwater in some locations are unfit for drinking. The average Total Dissolved Solids (TDS) of 1717 mg.L-1 is also indicating non-compliance with standards. Salinity zone maps were developed based on the observations. Further detailed studies need to be conducted to ascertain the factors that influence groundwater salinity, such as geology, island type, and seasonality.
Mostrar más [+] Menos [-]Pectin Production from Biowaste (Fruits & Vegetables) by Crosscurrent Solid-Liquid Extraction Technique
2022
Akshi Kunwar Singh | S. S. Kumar
The impact of fruit and vegetable waste is becoming a significant concern for the environment. The biomaterial waste generated from fruit processing industries is very high. When discharged as processed waste, it also increases water pollution. 45% of the total industrial organic pollution originates from food processing industries. These generated wastes are suitable for the production of biochemicals. Pectin is one such biochemical that plays a vital role in reducing the burden on the environment. Pectin helps in the manufacturing of confectionaries. Vegetable waste like beetroot, carrot, beans can also act as a source for pectin production. This study depicts extracting Pectin from mixed fruit pomace waste. Mixed fruit (Orange, Pomegranate, Banana & grapes) pomace waste reacts with 0.1N HCl. This reaction uses a 2-stage crosscurrent solid-liquid extraction technique. For its nature, obtained pectin was tested as calcium pectate using methylated spirit. The filtrate from 2-stage crosscurrent leaching was further dried in an oven. RSM technique helps in optimizing parameters like drying time, temperature, pH, and concentration. The experimental setup generated Pectin gave an efficiency of 11.52% for 22.4g of dried mixed fruit pomace waste.
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