4D imaging of lithium batteries using correlative neutron and X ray tomography with a virtual unrolling technique

The temporally and spatially resolved tracking of lithium intercalation and electrode degradation processes are crucial for detecting and understanding performance losses during the operation of lithium batteries. Here, high throughput X ray computed tomography has enabled the identification of mechanical degradation processes in a commercial Li MnO2 primary battery and the indirect tracking of lithium diffusion; furthermore, complementary neutron computed tomography has identified the direct lithium diffusion process and the electrode wetting by the electrolyte. Virtual electrode unrolling techniques provide a deeper view inside the electrode layers and are used to detect minor fluctuations which are difficult to observe using conventional three dimensional rendering tools. Moreover, the unrolling provides a platform for correlating multi modal image data which is expected to find wider application in battery science and engineering to study diverse effects e.g. electrode degradation or lithium diffusion blocking during battery cyclin

Tolerância da soja ao manganês em solução nutritiva em três temperaturas Soybean tolerance to manganese in nutrient solution under three temperatures

Foram estudados dois cultivares de soja (Biloxi e Forrest) em soluções nutritivas contendo quatro níveis de manganês (0,11; 2; 4 e 6 mg/litro) combinados com três diferentes temperaturas (22, 25 e 28ºC) em experimento efetuado em Campinas, em 1983. A tolerância foi medida, levando-se em consideração o peso seco das partes aéreas das plantas após 15 dias de cultivo nas soluções, os sintomas visuais de toxicidade e a concentração de manganês das folhas. Os resultados mostraram que, à medida que a temperatura das soluções variou de 28 para 22ºC, houve uma redução marcante no desenvolvimento das plantas dos dois cultivares, afetando, conseqüentemente, a produção de matéria seca. A 25ºC e ao nível de 2 mg/litro de Mn, foi possível distinguir o cultivar Forrest como sensível e Biloxi como tolerante, sendo esta combinação considerada ideal para fazer 'screening' de material genético. Esta separação, porém, poderia também ser feita nas temperaturas de 22 e 28ºC, respectivamente, nos níveis de 4 e 6 mg/litro de Mn. Na temperatura alta (28ºC), observou-se redução de toxicidade de Mn para soja. O cultivar Biloxi apresentou, sob todas as temperaturas, as maiores concentrações de Mn na parte aérea.<br>Two soybean cultivars (Biloxi and Forrest) were grown under three different temperaturas (22, 25 and 28ºC) in nutrient solutions containing four levels of manganese (0.11; 2; 4 and 6mg/l) in an experiment carried out at Campinas, in 1983. Mn tolerante differences were evaluated by dry matter weight of the above ground parts after a period of 15 days of growth. The results showed that as the temperature were reduced from 28 to 22ºC there was a reduction in the plant growth of the two cultivars which affected the dry matter weight. At 25ºC and at the level of 2 mg/l of Mn, Forrest was suceptible and Biloxi, tolerant, being this condition appropriate for screening soybean germoplasm for Mn tolerante. This separation could also be done at 22 and 28ºC at 4 and 6 mg/l levels of Mn, respectively. High temperature (28ºC) showed reduction of Mn toxicity in both soybean cultivars. The cultivar Biloxi always showed at all temperatures greater concentration of Mn than Forrest

Productivity and sustainability of a spring wheat–field pea rotation in a semi-arid environment under conventional and conservation tillage systems

A long-term rotation experiment was established in 2001 to compare conservation tillage techniques with conventional tillage in a semi-arid environment in the western Loess Plateau of China. We examined resource use efficiencies and crop productivity in a spring wheat (Triticum aestivum L.)-field pea (Pisum arvense L.) rotation. The experimental design included a factorial combination of tillage with different ground covers (complete stubble removal, stubble retained and plastic film mulch). Results showed that there was more soil water in 0-30 cm at sowing under the no-till with stubble retained treatment than the conventional tillage with stubble removed treatment for both field pea (60 mm vs. 55 mm) and spring wheat (60 mm vs. 53 mm). The fallow rainfall efficiency was up to 18% on the no-till with stubble retained treatment compared to only 8% for the conventional tillage with stubble removed treatment. The water use efficiency was the highest in the no-till with stubble retained treatment for both field pea (10.2 kg/ha mm) and spring wheat (8.0 kg/ha mm), but the lowest on the no-till with stubble removed treatment for both crops (8.4 kg/ha mm vs. 6.9 kg/ha mm). Spring wheat also had the highest nitrogen use efficiency on the no-till with stubble retained treatment (24.5%) and the lowest on the no-till with stubble removed treatment (15.5%). As a result, grain yields were the highest under no-till with stubble retained treatment, but the lowest under no-till with no ground cover treatment for both spring wheat (2.4 t/ha vs. 1.9 t/ha) and field pea (1.8 t/ha vs. 1.4 t/ha). The important finding from this study is that conservation tillage has to be adopted as a system, combining both no-tillage and retention of crop residues. Adoption of a no-till system with stubble removal will result in reductions in grain yields and a combination of soil degradation and erosion. Plastic film mulch increased crop yields in the short-term compared with the conventional tillage practice. However, use of non-biodegradable plastic film creates a disposal problem and contamination risk for soil and water resources. It was concluded that no-till with stubble retained treatment was the best option in terms of higher and more efficient use of water and nutrient resources and would result in increased crop productivity and sustainability for the semi-arid region in the Loess Plateau. The prospects for adoption of conservation tillage under local conditions were also discussed

Efeitos do manganês sobre o desenvolvimento e a composição mineral de quatro leguminosas forrageiras tropicais

Quatro leguminosas forrageiras tropicais (Galactia striata (Jacq) Urb; Glycine wightii cv. Tinaroo, Macroptilium atropurpureum cv. Siratro e Stylosanthes guianensis cv. IRI 1022) foram cultivadas em solução nutritiva recebendo doses de manganês de 0, 5, 10 e 20 ppm, com o objetivo de se verificarem os efeitos das doses crescentes do elemento sobre as diferentes espécies. Submetendo-se os dados de produção de matéria seca e de concentrações de macro e micronutrientes à análise estatística, observou-se o seguinte: a) O estilosantes foi o que se mostrou mais tolerante, não apresentando variação significativa na produção de matéria seca com o aumento dos teores de manganês. Não se observaram sintomas severos nas folhas ou nas raízes. A galactia também mostrou-se tolerante, apresentando queda significativa de produção em presença de 100 ppm de manganês e sentomas mais severos de toxidez que os apresentados pelo estilosantes. b) O Siratro e a soja mostraram-se sensíveis ao excesso de manganês. A soja mostrou a mínima produção em presença de 25 ppm do elemento não havendo modificação significativa nas concentrações mais elevadas. O siratro apresentou a mínima produção de matéria seca total em presença de 50 ppm de manganês. Os sintomas de toxidez apresentados pela soja foram mais severos que os apresentados pelas plantas de siratro. c) A adição de manganês provocou uma diminuição nas concentrações de cálcio, potássio e magnésio nas partes aéreas ou raízes das plantas estudadas; elevação dos teores de zinco e cobre nas aéreas ou raízes e de manganês na planta toda.Four tropical forage legumes (Galactia striata. Glycine wightii, Macroptilium atropurpureum and Stylosanthes guianensis), were grown in nutrient solution under varying levels of manganese (0., 25, 50 e 100 ppm). With respect to the differential tolerance between the species, the following was observed: a) Stylosanthes was not affected neither in therms of growth nor in terms of symptons of toxicity. Galactia was realtively less tolerant: its growth was significantly reduced by 100 ppm of Mn in the substrate which also caused severe toxicity symptons. b) Glycine and Macroptilium were sensitive to high Mn. Growth of the former was decreased by 25 ppm, being not further reduced by higher concentrations. The Mn concentration of 50 ppm caused the highest reduction of the growth of Macroptilium. Toxicity symptoms were more acute in the case of Glycine. c) The addition of Mn induced a decrease in the content of K, Ca and Mg. The levels of Cu and Zn in the tops decreased whereas the Mn concentration increased in the whole plant