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Geometries, Stability, Magnetic Behavior and Electronic Properties of Small PtxSny (x + y ≤ 5) Atomic Clusters
Elisa Marina Sosa Hernandez,
Peter Gilbert Alvarado Leyva,
John Martin Montejano Carrizales
Issue:
Volume 1, Issue 4, December 2021
Pages:
28-35
Received:
15 September 2021
Accepted:
23 December 2021
Published:
29 December 2021
DOI:
10.11648/j.reports.20210104.11
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Abstract: The nanoalloying process has allowed us to the possibility of creating new nanomaterials with new properties and new functionalities, one of the most studied nanoalloys both experimentally and theoretically is PtSn. We report the results of our calculations which were carried out to study the equilibrium structures, stability, magnetism and catalytic activity of small free PtxSny clusters with x + y ≤ 5, the study was done in the scheme of density functional theory as implemented in SIESTA code in the pseudopotential approach. Our results show that the global minimum structures prefer geometries with high coordination for the atoms, the nanoalloys rich in Sn atoms present a large average bond length and this study reveals a favorable mixing of Pt and Sn atoms, the clusters considered here leaves at least one Pt atom available for chemical reactions; in this regime we found magnetic only in 4 clusters with a ferromagnetic-like order into the nanoalloys. The value of the binding energy per atom increases as the number of Sn atoms decreases in the clusters, the reactivity of the PtSn nanoalloys was studied considering the electron affinity, the ionization potential and the chemical hardness, we found that some clusters with 5 atoms present the lowest value in the chemical hardness making them favorable as catalysts.
Abstract: The nanoalloying process has allowed us to the possibility of creating new nanomaterials with new properties and new functionalities, one of the most studied nanoalloys both experimentally and theoretically is PtSn. We report the results of our calculations which were carried out to study the equilibrium structures, stability, magnetism and catalyt...
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Review on: Inter-Cropping System and Its Advantages
Issue:
Volume 1, Issue 4, December 2021
Pages:
36-42
Received:
22 November 2021
Accepted:
16 December 2021
Published:
29 December 2021
DOI:
10.11648/j.reports.20210104.12
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Abstract: The only way to increase agricultural production in the small or marginal units of farming is to increase the productivity per unit time and area. One method of increasing productivity is by using multiple cropping systems. It uses management practices where the total crop production from a single piece of land is achieved by growing single crops in close sequence, growing several crops simultaneously, or combining single and mixed crops in some sequence. Intercropping which is one of the multiple cropping systems is a growth of two crops in the same field, where the component crops are not necessarily sown at the same time nor harvested at the same time, but they are grown simultaneously for a portion of their growing periods. The objective of this paper is to revise intercropping systems and its advantages across the world. Some of the advantages of intercropping are increase productivity, greater stability of yield over different seasons, better use of growth resources, better control of weeds, pests and diseases, control erosion, fixation of nitrogen by the legume component and others. In Ethiopia, maize intercropped with common bean reduced the severity of Angular leaf spot (ALS) disease. When susbtaible faba bean cultivar was grown with either barley, oat, triticale or wheat, on average there was 47.2% reduction of disease severity for intercrops compared to that of the faba bean monocrop and 29.6% less disease area under the disease progress curve (AUDPC) for intercrops compared to the faba bean monocrop. Disease spread was reduced in mixed cropping because physical barriers against aerial pathogens and their vectors, trapping effect, altering microclimate (shading and humidity) and by spacing effect. The prevalence of the legume-based intercropping systems improves soil fertility by biological N fixation. Biological N; fixation (BNF) is a natural process in legume crops, where atmospheric nitrogen (N2) is fixed into ammonia (NH3) in plant root nodules by a symbiotic form of Rhizobia. At the end yield advantage occurs because component crops differ in their use of growth resources in such a way that when they are grown in combination they are able to ‘complement’ each other and so make better overall use of resources than when grown separately. For example Sorghum and common bean row intercropping gave the highest agronomic advantage (43%) at Babile and 40% at Alemaya over sole cropping of the component crops.
Abstract: The only way to increase agricultural production in the small or marginal units of farming is to increase the productivity per unit time and area. One method of increasing productivity is by using multiple cropping systems. It uses management practices where the total crop production from a single piece of land is achieved by growing single crops i...
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Observational Study on Infestation and Management of Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) at Jimma, Ethiopia
Issue:
Volume 1, Issue 4, December 2021
Pages:
43-46
Received:
25 November 2021
Accepted:
24 December 2021
Published:
31 December 2021
DOI:
10.11648/j.reports.20210104.13
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Abstract: Spodoptera frugiperda is an invasive and a destructive insect pest of maize and other cereals in Ethiopia. Fall armyworm infestation and different management options were assessed at Jimma agricultural research field stations. Preliminary findings show that percentage of fall armyworm infestation ranged from 3.57% to 100% with average infestation of 54.73% in main growing season. Severe infestation due to fall armyworm is expected to decrease yield. To reduce its infestation, massive larvae collection, phermonal control and insecticides were used. Within a month a total of 601 fall armyworm moths were captured by a single sex pheromone trap. Per week 77 to 211 Spodoptera frugiperda was captured. In addition, handpicking is the most effective cultural practice for fall armyworm management. During assessment, earwig predator was abundantly found both during wet and dry season that could play a role in reducing the fall armyworm population as biological control agent. This study highlights the importance of using phermonal control, hand picking, early planting and biological agent can manage fall armyworm, and used as component of integrated pest management. Further studies are recommended to strengthen more the findings of the current study especially on the massive rearing of indigenous natural enemies and yield loss due to fall armyworm.
Abstract: Spodoptera frugiperda is an invasive and a destructive insect pest of maize and other cereals in Ethiopia. Fall armyworm infestation and different management options were assessed at Jimma agricultural research field stations. Preliminary findings show that percentage of fall armyworm infestation ranged from 3.57% to 100% with average infestation o...
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Review on Climatic Change Upshot on Livestock Husbandry in Ethiopia
Petros Chavula,
Benson Turyasingura
Issue:
Volume 1, Issue 4, December 2021
Pages:
47-53
Received:
5 December 2021
Accepted:
25 December 2021
Published:
31 December 2021
DOI:
10.11648/j.reports.20210104.14
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Abstract: Climate change and extreme weather events have an impact on crop and livestock husbandry in developing countries, particularly in Sub-Saharan Africa. The direct effects posed by anthropogenic to changes in environmental conditions have been thoroughly proven in recent years through empirical studies. As a result, since 1960, the global average temperature has risen by 1 degree Celsius. In Ethiopia, climate change has had an impact on livestock production and productivity. The majority of livestock owners in the country believe climate change will influence pasture shortages, water shortages, livestock genetic resource losses, loss of livestock life, and less meat on mature livestock or reduced growth rate to achieve the required weight. Consequently, regarding mature animals, that leads to reduced livestock physiological processes, low milk supply, and impaired procreant function. Drought oxen will become malnourished and will be unable to generate the required draught power or energy for farm activities such as ox-cart, ploughing, causing crop cultivation to be hampered. Moreover, conferring to patterns and occurrences of rainfall have a significant impact on the present quantity of water and pasture for livestock. As a result, the absence of quality pasture for livestock and enough water roots livestock productivity and reproduction to suffer in Ethiopia. Higher temperatures caused by climate change may hasten the growth of diseases and parasites that may proliferate in or outside of the host livestock for too long. However, climate variation and climate change are anticipated to far reach more detrimental effects on livestock well-being and productivity, particularly in disadvantaged areas. Therefore, in these food and human livelihood are of essence for survival. The purpose of this study is to highlight the potential effects of changes in climate contribution to livestock production and productivity in Ethiopia.
Abstract: Climate change and extreme weather events have an impact on crop and livestock husbandry in developing countries, particularly in Sub-Saharan Africa. The direct effects posed by anthropogenic to changes in environmental conditions have been thoroughly proven in recent years through empirical studies. As a result, since 1960, the global average temp...
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Efficacy of Insecticides Application for Management of Pod Borer (Helicoverpa armigera) of Chickpea in Midland of Guji Zone, Southern Ethiopia
Deresa Shumi,
Tekalign Afeta,
Belachew Debelo,
Rehoboth Nuguse
Issue:
Volume 1, Issue 4, December 2021
Pages:
54-58
Received:
1 November 2021
Accepted:
26 November 2021
Published:
31 December 2021
DOI:
10.11648/j.reports.20210104.15
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Abstract: Chickpea pod borer (Helicoverpa armigera) is a major insect pest constraining chickpea production in Ethiopia. A field experiment was conducted to evaluate and select the efficacy of insecticides for effective foliar spray against the pod borer in chickpea crop under field using two chickpea varieties; Dalota and Habru with six insecticides (Helerat 5% E.C at 400 ml/ha, Profit 72% E.C at 500 ml/ha, Perfecto 175 SC at 150-400 ml/ha, Con-fidence 35% at 250 ml/ha, Lipron 50 SC at 600 ml/ha and Highway 50 EC at 250 ml/ha). The result revealed that Helerat was the most effective against pod borer on percent larval reductions. Helerate, Profit and Highway are more effective and reduced H. armigera larvae population by 56.67%, 51% and 45.62% on Habru variety respectively. Helerat resulted maximum seed yield 2349kg/ha and 2049 kg/ha for Dalota and Habru, respectively. The plot sprayed with Helerat gave the maximum net return birr 75102/ha and 78,525/ha for Dalota and Habru, respectively. Therefore, production of chickpea with the application of Helerate was most profit for economical production compared to other insecticides and recommended for the study area.
Abstract: Chickpea pod borer (Helicoverpa armigera) is a major insect pest constraining chickpea production in Ethiopia. A field experiment was conducted to evaluate and select the efficacy of insecticides for effective foliar spray against the pod borer in chickpea crop under field using two chickpea varieties; Dalota and Habru with six insecticides (Helera...
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