Henrik Davidsson

Mn diffusion in Ga1-xMnxAs/GaAs superlattices

Ga1−xMnxAs∕GaAs superlattices with Mn concentrations of 1% and 5% in the Ga1−xMnxAs layers and a GaAs spacer thickness of 4 and 60 GaAs monolayers have been studied by cross-sectional scanning tunneling microscopy. By achieving atomic resolution of the superlattices, we observe individual Mn atoms in the Ga1−xMnxAs layers and in the GaAs spacer. We find that about 20% of the total amount of Mn diffuses from the GaMnAs layers into the GaAs spacer layers. Our results can be related to previous measurements of the magnetic properties of short period Ga1−xMnxAs∕GaAs superlattices.

Facilitating integrated agricultural technology development through participatory research

ABSTRACT Purpose: In this paper, we discuss the role of participatory research in integrated agricultural technology development using the example of a solar fruit drying project in Mozambique. Design/methodology/approach: We engage in seven participatory exercises with groups of farmers from two farmers’ associations in Inharrime district in Mozambique to identify their needs for solar fruit drying that are crucial for solar dryer technology design. We focus in the analysis on three of these exercises including a daily schedule exercise, SWOT (Strengths Weaknesses Opportunities and Threats) analysis and technology requirement exercise. Findings: Participatory research takes a dual function for integrated agricultural technology development. First, it can help to identify the technology needs of farmers and second it can enable the exchange and creation of different sets of knowledge for agricultural technology development between multiple stakeholders. Practical implications: Participatory research provides a tool for joint knowledge exchange and creation, which allows the identified technology requirements to be translated into practical technology design. Theoretical implications: This paper extends the concept of integrated research to integrated agricultural technology development and shows how participatory research is a tool that enables transdisciplinarity, which presents the most desired form of integrated research. Originality: This research is highly relevant for researchers working in an interdisciplinary environment with agricultural technology development in cross-cultural contexts. From a meta-level perspective, it provides insights for joint and integrated technology development.

The importance of gender roles and relations in rural agricultural technology development: a case study on solar fruit drying in Mozambique

Abstract Many agricultural technology interventions that aim to improve farmers’ livelihoods focus on households as the unit of analysis and ignore gender roles that entail different benefits and costs for different household members. Agricultural projects have shown limited success where gender roles and relations were ignored and thus more gender sensitive research is needed in agricultural technology development to ensure social acceptance. In this study, we address this need by investigating the importance of gender roles and relations in the case of solar fruit drying in Mozambique. We apply a variety of gender sensitive participatory methods that enable farmers to actively take part in the technology development process. First results indicate that the costs and benefits of solar fruit drying are not shared equally between genders. Women have much less time available for using the solar fruit dryer. The data also indicate that certain steps in the solar fruit drying process are clearly gender divided. We finally discuss potential mechanisms that can be applied in agricultural technology projects that can create awareness of the risk to reproduce traditional gender roles and unequal relations in the development process of new agricultural technologies.

Heat Loss for a Run-Around Hybrid Ventilation System with Heat Recovery

The heat recovery system for ventilation is of major importance when low energy buildings are built. One alternative to the mechanical ventilation systems with heat recovery is to use a brine based run-around system that allows for heat recovery in for instance hybrid ventilated buildings. This type of heat recovery system has the potential to lower the need for electricity for the fans. Also, the installation has the potential to be simpler when pipes transporting the brine replace traditional air ducts. However, pipes needed to transport the brine will suffer from thermal losses. This will lower the efficiency of the heat recovery system. High losses could in practice make the system unusable. In order to estimate how much this affects the annual heat recovery a simulation tool was developed using TRNSYS. The result from the investigation shows that the losses for a system with 40 m pipes in total are approximately 300 kWh annually. This corresponds to approximately 9% of the energy savings from the ventilation heat recovery system. Insulating the pipes can reduce this heat loss by approximately 250 kWh annually. (Less)