Effect of Layer Thickness on Structural, Morphological and Superconducting Properties of Nb\u3csub\u3e3\u3c/sub\u3eSn Films Fabricated by Multilayer Sequential Sputtering

Superconducting Nb3Sn films can be synthesized by controlling the atomic concentration of Sn. Multilayer sequential sputtering of Nb and Sn thin films followed by high temperature annealing is considered as a method to fabricate Nb3Sn films, where the Sn composition of the deposited films can be controlled by the thickness of alternating Nb and Sn layers. We report on the structural, morphological and superconducting properties of Nb3Sn films fabricated by multilayer sequential sputtering of Nb and Sn films on sapphire substrates followed by annealing at 950 °C for 3 h. We have investigated the effect of Nb and Sn layer thickness and Nb:Sn ratio on the properties of the Nb3Sn films. The crystal structure, surface morphology, surface topography, and film composition were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive X-ray spectroscopy (EDS). The results showed Sn loss from the surface due to evaporation during annealing. Superconducting Nb3Sn films of critical temperature up to 17.93 K were fabricated

Let us conserve and exchange seeds: celebrating traditional crop diversity of the Nepali lowlands

A seed fair is an activity to create awareness about and appreciate local crop diversity, exchange seed and related knowledge, and celebrate farmers’ efforts to conserve agrobiodiversity. It takes considerable time and effort to organize a seed fair. This brief describes the seed fair organized at the Agyauli Community Seedbank, Nawalparasi in the southern region of Nepal. About 30 members of 10 community seedbanks from the terai (the southern lowland) region of Nepal came together for this. Apart from exchanging seeds of traditional crop varieties, they also shared stories about the socio-cultural, religious, spiritual, nutritional and medicinal values of their varieties. The recent formal registration of the Community Seed Banks Association of Nepal (CSBAN) was also celebrated

Deposition of Nb₃Sn Films by Multilayer Sequential Sputtering for SRF Cavity Application

Nb3Sn is considered as an alternative of Nb for SRF accelerator cavity application due to its potential to obtain higher quality factors and higher accelerating gradients at a higher operating temperature. Magnetron sputtering is one of the effective techniques that can be used to fabricate Nb3Sn on SRF cavity surface. We report on the surface properties of Nb3Sn films fabricated by sputtering multiple layers of Nb and Sn on sapphire and niobium substrates followed by annealing at 950°C for 3 h. The crystal structure, film microstructure, composition and surface roughness were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and atomic force microscopy (AFM). The RF performance of the Nb3Sn coated Nb substrates were measured by a surface impedance characterization system. We also report on the design of a multilayer sputter deposition system to coat a single-cell SRF cavity

A novel approach for implementing community seed banks in the mountain area of Nepal

Community seed bank (CSB) is one of the approaches successfully applied in Nepal and globally for conservation and use of local crop diversity for food and agriculture. However, there are only a few success examples of CSBs in high mountain areas of Nepal, particularly focusing on traditional underutilized crops. This chapter aims to present the modality and experiences of implementing community seed banks in mountain districts, namely, Humla, Jumla, Lamjung and Dolakha, by the UNEP GEF Local Crop Project (LCP) jointly implemented by Bioversity International, NAGRC, DoA and LI-BIRD. The project was implemented in 2014 in Nepal for providing diversity rich solutions and mainstreaming the conservation and use of local agricultural biodiversity in the mountain agricultural production landscapes. The LCP adopted Diversity Field School (DFS) approach to sensitize and mobilize communities about the importance of local crop genetic resources, paving way in realizing the need of CSB and its institutionalization. DFS approach has been found effective to identify and mobilize custodians of agrobiodiversity, promote good practices such as participatory variety selection, grass-roots breeding, food fairs and promote farmer- to-farmer learning and sharing as a part of local capacity building processes. DFS approach has empowered women farmers to take leadership roles in managing community seed banks. The project engaged local governments (Palikas) from the beginning to make them realize the vital need of CSBs, strengthen local seed systems as a mechanism to increase access to quality seeds of traditional and underutilized crop species. It has resulted a positive outcome to develop ownership on institutionalizing CSB in local agriculture development plans and providing significant amount of financial resources and material support to establish and sustain CSBs in LCP sites. In remote high mountain areas, where seed business opportunity is limited; engagement of and ownership of local government is crucial to sustain CSBs

Symbiotic nitrogen fixation, growth and yield response of common bean and cowpea for Rhizobia inoculation and micronutrients (B and Mo) application in mid-hill regions of Nepal

This is a CIFSIRF funded project.Challenges associated with legume production in Nepal include: lack of high yielding varieties and crop specific management (e.g., disease/pest management) practices, loss of soil fertility including micronutrients, poor access to agricultural inputs and services, shortage of irrigation water, lack of mechanization, and labour shortages which led to poor yields and low economic returns to farmers (Chapagain and Gurung, 2010; Chapagain and Raizada, 2017). Farmers mostly used untreated seeds from previous season harvest to cultivate these crops and very little attention has been given to study the effects of bacterial inoculation on the crop performance and soil health through systemic on-farm trials. Symbiotic nitrogen fixation of 3 legumes can be improved by introducing efficient rhizobia strains for N fixation (Thilakarathna and Raizada, 2017), and also through application of soil deficient micronutrients which are important for different stages of SNF (Weisany et al., 2013). This research explores the opportunities to use different rhizobia strains (native as well as exotic) along with micronutrients (Boron and Molybdenum) on two legume crops (e.g., cowpea and common bean) to enhance SNF, crop yields (grain and plant biomass), plant and grain N content, and offers the most productive combination(s) for each crop

Seasonal and year-round intercropping systems for smallholder farmers : results from on-farm intercropping trials on terraces in Nepal on maize, millet, mustard, wheat and ginger

We would like to thank the Canadian International Food Security Research Fund (CIFSRF), jointly sponsored by the International Development Research Centre (IDRC, Ottawa) and Global Affairs Canada (GAC) for funding.Low yield and total land productivity are major challenges associated with smallholder terrace agriculture in developing countries. Crop intensification and diversification by introducing legumes as intercrop could help alleviate these challenges. We compared 10 intercrop combinations with sole cropping system for two rotation cycles (2015-17) to identify the most productive and economic intercrop combinations for smallholder terrace agriculture. In the spring-summer season (March/April-July/August), cowpea (var. Makaibodi and Suryabodi) and bean were intercropped with maize in rows of 1:1 whereas soybean, blackgram and horsegram were broadcasted with millet (30:70 ratios) during summer-rainy season (July/August-November/December). Pea and lentil were used as winter intercrop (November/December-March/April) in wheat (30:70 ratios) while mustard was planted with pea. Ginger was planted with maize in 1:1 rows during spring-summer season in which the maize rows were replaced by soybean and lentil during summer-rainy and winter season, respectively

Key directions for research and development of superconducting radio frequency cavities

Radio frequency superconductivity is a cornerstone technology for many future HEP particle accelerators and experiments from colliders to proton drivers for neutrino facilities to searches for dark matter. While the performance of superconducting RF (SRF) cavities has improved significantly over the last decades, and the SRF technology has enabled new applications, the proposed HEP facilities and experiments pose new challenges. To address these challenges, the field continues to generate new ideas and there seems to be a vast room for improvements. In this paper we discuss the key research directions that are aligned with and address the future HEP needs.Comment: contribution to Snowmass 202