Results 1 - 10 of 142
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[en] Water deficit is a serious threat to the global crop production. Marigold (Tagetes erecta L.), an economically important annual is resistant to drought stress, however, anatomical adaptations confirming drought tolerance are still unexplored. In this context, key growth and anatomical difference of two marigold (T. erecta L.) cultivars, Inca (drought resistant) and Bonanza (drought sensitive), to water deficit conditions were studied. Plants of both marigold cultivars were subjected to control (T0; 100% FC) and water deficit conditions (T1; 60 FC and T2; 40 FC) three weeks after transplantation. Drought stress caused a significant reduction in growth of cv. Bonanza while cv. Inca remained unaffected. However, drought stress significantly affected anatomical features in both marigold cultivars. Increasing drought stress levels enhanced the reduction in root vascular area of both cultivars. Under both levels of water stress, shoot cortex area decreased only in cv. Bonanza. Leaf thickness and cortex area decreased at 40% FC in both cultivars. The growth and biomass performance of cv. Inca was better than cv. Bonanza under water stress conditions. (author)
[en] Of all series of diseases that might define survival rates, seed size was investigated intensively and is regarded as of specific importance at stages of early seedling. The larger-seeded species seedlings generally perform better than smaller seeded species seedlings to face various hazards. However, the smaller-seeded species are to confer a growth advantage in the favorable habitats. This study studied the correlation between seed size and the compensatory capacity of cotyledon to recover from simulated herhivory, and if the capacity could be affected by seeding depth, and whether smaller seeded species grow faster than larger ones in response to cotyledonsherbivoryat seedling stage. Five defoliation treatments (control, one cotyledon damage, both cotyledons damage, one cotyledon and apical meristem damage, apical meristem damage) and two seeding depths (1cm and 3cm) were used in the pot experiment. The compensation of cotyledon area, thick and mass were increased with increasing seed size, but cotyledon longevity was decreased with increasing seed size in each defoliation level, and there is a significant effect of seeding depth on them. All the factors strongly affected the seedlings biomass and significantly altered belowground and aboveground biomass ratio of seedlings. The relative growth rate of smaller-seeded species is significant higher than that of large-seeded species in response to cotyledonsdamageat early seedling stage. The growth advantage of smaller seeded species seedlings and the difference of cotyledonal compensation ability may account for a range of coexisting strategies. (author)
[en] The participation of renewables sources of energy in the Brazilian Energy generation mix is among the highest in the world. The Brazilian government has been striving to develop clean energy generation projects and to diversify the electricity matrix, which is strongly dependent of hydropower. This paper gives an overview of recent activities aimed at the development of nuclear power as effective option for collaborate with the diversification of the Brazilian energy mix, mitigate the impacts from climate change and democratize the population's access to electricity throughout a continental country territory.
[en] The influence of real operating conditions of the solar modules (solar radiation intensity, ambient temperature, wind speed) on their output performances is analyzed. An analytical expression is proposed, allowing to approximate the temperature of the solar modules. An algorithm for assessing the operating power of solar modules based on their data sheet information has been developed. The MatLab-Simulink simulation has shown that the identification of ambient and solar module temperatures leads to errors of up to 20 percent in estimating the operating power of solar modules
[en] This study is concerned with the sorption behavior of natural radionuclides (226Ra, 210Po, 228Th - originated from TENORM waste associated with petroleum industry) onto silica/olive pomace nanocomposite. Initially, nanocomposites of extracted silica and olive pomace are prepared and characterized by physicochemical techniques. In the batch technique, 60% SiO2 40% olive pomace (AM3) nanocomposite showed a considerable group sorption for 226Ra and 210Po larger than 228Th in 1M HNO3 and HClO4 solutions. In case of sorption by the compacted disc, sorption of 226Ra was similar to batch method, sorption of 228Th increased slightly to ∼ 17%, while sorption of 210Po was decreased to 77%. Thus, AM3 nanocomposite can be considered as an efficient nano-adsorbent for sorption and separation of Ra-isotopes and 210Po-radionuclides from 226Ra-210Po-228Th admixture associated with nuclear and non-nuclear industries. (author)
[en] This work investigates the foliage’s changes reported on seedlings and regenerated sprouts of Acacia saligna (Labill.) H.L.Wendl. cultivated in Tunisia. First, a tracking of leaves development on 50 three-month old heteroblastic seedlings was performed. The transition from juvenile foliage to mature leaves occurs through four several stages. The first two leaves were pinnately compound and stand opposite each other (stage 1). The following initiated five leaves are alternate and bipinnately compound (stage 2). The eighth leaf corresponds to a transition form (stage 3). After three months of growth, from the ninth leaf, seedlings start the initiation of phyllodes (stage 4). Second, in order to better understand the leaves’ chronological switching and to examine the influence of the cutting height on the sprouting ability and on the biomass production, a total of 60 adult trees of A. saligna were randomly selected and cut at heights of 10, 30 and 50 cm above ground level (20 trees each). The results indicated that the 50 cm stump height alowed a maximum rejuvenation expressed by the highest number of sprouts and juvenile bipinnately compound leaves; reminding those that have been developed on seedlings. Also, six-month old sprouts promoted the best transition phenomenon rate, the longest and the broadest phyllodes that are more vigorous than those developed on seedlings and adult trees. (author)
[en] At a time when the world is facing global warming and the burden on natural resources is increasing. Now, the world is switching towards cleaner form of energies. Renewable solar roof top is one of them. Most developed economies of the world have started their solar programmes by targeting household rooftops. Solar power has reached grid parity and is the cheapest source of distributed power across the world
[en] Variable renewable energy sources are increasingly contributing to global energy generation today and are planned to play an even more prominent role in the future. Recent predictions show that the share of renewables (including non-variable) could increase from 22% in 1995 to 28% in 2020 and more than 70% by 2050. At the same time nuclear power generation is predicted to be fairly constant at approximately 3,000 TWh per year, with global power generation increasing to approximately 50,000 TWh by 2050. As a result of the rapid increase in renewable energy production, mostly from solar, wind and hydropower, the global share of nuclear power production is expected to decrease from 18% in 1995, and 10% in 2020 to approximately 5% in 2050. Nuclear power remains the second most important (after hydropower) dispatchable greenhouse gas lean energy source and is foreseen to play an important role in balancing variable renewable energy generation from renewables.
[en] World energy demand is increasing and non-renewable resources are decreasing by exponentially putting a huge burden on the energy sector specifically on the oil and gas industry. To overcome these challenges, renewable energy is the best option with production optimization in the oil and gas sector. However, among all renewable energies, geothermal is the most suitable energy due to its sustainability and presence around the clock. Moreover, there are three types of wells for harnessing geothermal energy such as: producing oil and gas well, abandoned oil and gas wells and geopressured brine well with dissolved gas. In this research study, the author’s considers the technical aspects of electricity generation through oil and gas wells. The power capacity of these wells is determined by the production rate of the well mass flow (m) and temperature (T) of these wells. The main factors that control the wellhead temperature are mass flow rate and formation temperature. Our assessment of gas-producing well in the Kandhkot region showed the wellhead temperature of the produced fluid is too low, compared to ambient temperature for commercial generation of geothermal power. In our work, a conceptual design system to produce power from produced gas by using Solid Works Software is proposed and we have found some positive results. Seven well from the Kandhkot gas field were selected with different mass flow rates and negligible wellhead temperature difference. Author’s found the minimum power net output 21kW at the gas mass flow rate of 0.098504 kg/s with 7.5% thermal efficiency and maximum net output 27.5 kW at gas mass flow rate of 4.102524 kg/s with 10% thermal efficiency. The overall net output power produced from seven well is 174kW and can supply to local communities. (author)
[en] In the last decades the use of satellite images and remote sensing for agricultural activities has increased to encompass factors such as plant growth or biomass. However, satellite images may not be available for all regions or during all seasons (cloud cover) and precision agriculture requires smaller resolutions for mapping small elements as for example trees or smaller crops. The application of multispectral cameras mounted on UAVs (Unmanned Aerial Vehicles) is therefore a new and fast developing market and methodology. In order to explore its opportunities a training course on the use of UAVs and multispectral camera systems in agriculture was organized for the staff of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture in Vienna, Seibersdorf from 23-27 September 2019. The course was led by Mr Erik de Badts (Micasense) but included several guest lecturers from different companies and research facilities. In total six staff members from the SWMCN laboratory and section participated. The course provided insights into the different UAVs available, camera systems, software and data processing programmes. IAEA staff learnt how to plan a UAV survey and process acquired data.