Design and testing of thermoacoustic electricity generators for rural areas of developing countries

This thesis outlines a detailed study comprising the simulation, design, construction, and experimental validation of two prototypes of looped-tube travelling wave thermoacoustic electricity generators. The prototypes used air at atmospheric pressure as working gas, an audio loudspeaker as linear alternator, while most of acoustic resonator parts were made of PVC components. The hot heat exchangers were externally heated. The first prototype was a small size, single-stage generator powered by combustion from a propane gas burner. The feedback pipe includes a branched alternator and an acoustic impedance matching stub. The effect of the heat input on the generator performance has been investigated. 13W of electrical power, extracted by 12Ω electric load, was achieved at flue gas temperature of 627.4°C and regenerator temperature difference of 430K. The second prototype was a larger sized (resonator inner diameter is 128 mm) two-stage generator. Here, the heat source was an electric air heat “gun” than provides air stream at 650°C. Firstly, the single-stage engine was examined at frequencies of 48.82, 64.45 and 70.31Hz. The experiments show that the streaming can reduce acoustic power from 110.63 to 63.4W at 70.31Hz. Furthermore, the acoustic power increases from 111.45 to 153 W when the frequency is increased from 48.82 to 64.45 Hz. Subsequently, a linear alternator was attached to the engine to convert the produced acoustic power into electricity. At a load of 9Ω the single-stage generator achieved 8.52W of electricity and 1.47% efficiency. The generator was further improved by incorporating an identical second stage. The effects of matching stub length, variable load and heat input were investigated. The two-stage prototype generated 14.18W of electrical power to a load of 9Ω with a thermal-to-electrical efficiency of 2.1%. The result indicated that the generators can supply enough electricity to power LED bulbs, and charge mobile phones and batteries

Economic Analysis of Spatial Integration of Pulse Market in Ethiopia; A case of Selected Pulse Market in Ethiopia

In order to solve the problem of food insecurity the Government of Ethiopia has adopted different strategies since the introduction of agricultural extension services in the early 1970s, to improve the performance of the agricultural sector. However, most of this strategy has focused on how to increase agricultural productivity at the farm level through the dissemination of improved production technologies, while the marketing aspect has been given less attention.  Considering this, in order to improve the market efficiency, significant numbers of empirical studies have been conducted on market integration but they focused mainly on cereal[1] market while pulse market has not been given adequate attention. Yet pulse is the third largest export crop in the country and generates USD 232.5 million annually and it has been showing a significant growth in export and production in the last decade. The study assesses the price transmission of selected pulse market in Ethiopia using monthly wholesale price data in Birr/Quintal covering the period January 2003 to December 2013 for Horse beans and Chickpeas from Ethiopian Grain Trade Enterprise. The stationarity of the price data was tasted using Augmented Dickey-Fuller (ADF) and Phillips-Perron tests. To test the co integration level Engle and Granger (Engle and Granger, 1987) test were applied. To identify which market price change will cause a price change in other market, Granger Causality model was used. The selected markets are Addis Ababa as a central market; Adama as closest market based on distance form central market; Diredewa as remotest both for Horse beans and Chickpeas. While Desse and Gonder as main producing market of Horse beans and Chickpeas respectively. The finding indicates that all the selected markets are co integrated. However, Addis Ababa- Desse for the case of Horse beans and Addis Ababa- Gonder for Chickpeas markets have strongly integrated.  Concerning causality, Addis Ababa - Desse, Addis Ababa - Adama, Desse - Diredawa markets are unidirectional while Desse - Adama are bidirectional for horse bean. However, for Chickpeas, all the selected markets do not Granger Cause each other in both directions except between Diredawa - Adama which were unidirectional. This implies that there is a need of improvement in market information systems especially to producing markets, and also timely accurate price information for trade participant to distribute commodities from surplus area to deficit markets. Key Words: Pulse, Ethiopia, Granger Causality, price transmission [1] Studies focused mainly on cereal market: Maize, Wheat, Sorghum and Teff (Negassa, 1998; Negassa et al., 2004; Getnet et al., 2005; Getnet, 2007; Tadesse and Shively, 2009 and Sinishaw, 2013)

Revisiting the Kaleidoscope Model for Policy Analysis and Exploring its Applicability to the Complex Agrifood Systems of Countries in Central and West Asia and North Africa: Methodological Guideline

Policies are critical to improving agrifood systems innovations and overall economic performance. While favorable policy decisions shape the incentives and actions of stakeholders, suboptimal policies could create bottlenecks and hinder development progress (Haggblade and Babu 2017; Resnick et al. 2018). Therefore, having an impact on policy decisions requires a good understanding of a given country’s underlying policy processes. Policies are, however, implemented by a range of stakeholders and bringing them together for action is often a challenge. The Kaleidoscope Model (KM) can be used to analyze policy and institutional constraints and key drivers of agrifood policy change in Central and West Asia and North Africa (CWANA). This research is being implemented by a team of researchers from CGIAR research centers ICARDA, IFPRI, and IWMI and in collaboration with international and national partners across CWANA countries

Characterizing and Assessing Innovation Platforms in Central and West Asia and North Africa

Innovation platforms (IPs) can provide a multidisciplinary research environment to test outcome-oriented research/ scientific ideas, technologies, and innovations. These are particularly effective when agrifood challenges require cross-sectoral solutions and joint efforts of stakeholders who have a stake in both the problem and solution. IPs allow stakeholders to experiment together and share knowledge, resources, benefits, and risks for issues they cannot solve on their own, and benefit from the synergistic effects of working together. IP functions include innovations relating to technology, capacity development, organization, policy, institutional governance, and the integration of these dimensions. Contemporary tools of monitoring, evaluation, and learning (MEL) can be used to assess the IPs’ contribution to these dimensions and generate lessons for future scaling. Three aspects of the IPs can be monitored and evaluated. These are activities, process changes, and results generated by the IP for beneficiary groups. The member stakeholders or a designated sub-team should define the indicators and rubric thresholds to measure these changes. The International Centre for Agricultural Research in the Dry Areas (ICARDA) can upgrade its research stations into National Innovation Platforms (NIPs) by engaging diverse partners and stakeholders to jointly identify their challenges and test their innovations to address those challenges. For example, improved varieties of cereals and forages could be entry points to set up NIPs in these research stations. ICARDA’s country offices may be able to characterize the research stations and take the initiative to set up a NIP. The characterization and assessment of the research stations can proceed with the involvement of key stakeholders, including policymakers and the private sector

National Alliance of Stakeholders for the Wheat Sector in Lebanon: Multistakeholder Workshop Report

On July 24, 2023, the International Center for Agricultural Research in the Dry Areas (ICARDA) and the Lebanese Agricultural Research Institute (LARI) under the Ministry of Agriculture organized a Multistakeholder Workshop on “National Alliance of Stakeholders for the Wheat Sector in Lebanon”. The agenda of the workshop is provided in Appendix 1. More than 20 representatives of various stakeholders attended the workshop, including officials of key government ministries and agencies, researchers from multiple research institutes, non-governmental and non-profit organizations, representatives of the United Nations (UN) agencies, and the private sector

Knowledge, attitudes and practices of health professionals towards people living with lymphoedema caused by lymphatic filariasis, podoconiosis and leprosy in northern Ethiopia

BACKGROUND: Podoconiosis, lymphatic filariasis and leprosy are highly stigmatised neglected tropical diseases that cause lymphoedema. Their enormous impacts on health-related quality of life, mental health and economic productivity can be significantly reduced by morbidity management and disability prevention (MMDP) services, but to deliver such services requires appropriate training of healthcare professionals. The aim of this study was to assess the knowledge, attitudes and practices (KAP) of rural Ethiopian healthcare professionals towards people with lymphoedema as a way to assess training needs. METHODS: This study used questionnaires to quantitatively assess KAP towards people with lymphoedema among rural healthcare professionals in northwest Ethiopia before and 12 months after a short training intervention. RESULTS: Questionnaires were administered to 14 health professionals at baseline and 21 at follow-up. At baseline, 71% (10/14) were found to hold at least one stigmatising attitude towards lymphoedema patients, compared with 66% (14/21) at follow-up. Large gaps in knowledge were noted, with many unable to identify ways of treating/preventing the diseases. CONCLUSIONS: This study showed high proportions of healthcare workers holding stigmatising views and lacking essential knowledge about lymphoedema. To maximise the impact of MMDP interventions, further research is urgently needed to understand how to address these issues

A qualitative study on the implementation of a holistic care package for control and management of lymphoedema: experience from a pilot intervention in Northern Ethiopia

Background Neglected Tropical Diseases (NTDs) such as podoconiosis, lymphatic filariasis (LF) and leprosy mainly affect communities in low resource settings. These diseases are associated with physical disability due to lymphoedema as well as poor mental health and psychosocial outcomes. Integration of care across these NTDs at primary health care level, which includes mental health and psychosocial care alongside physical health care, is increasingly recommended. Methods A holistic integrated care package was developed and piloted as part of the EnDPoINT project in Gusha district, Awi zone, Ethiopia. The intervention was conducted at the health care organization, health facility and community levels. To assess the impact of the care package in terms of acceptability, scalability, sustainability and barriers to implementation, a qualitative study was conducted in January 2020. This included four focus group discussions (29 participants) and ten key informant interviews with decision makers, health professionals, patients, and community representatives. Results The integrated lymphoedema care package was found to be efficient compared to vertical programs in saving time and resources. It also resulted in improved awareness of the causes, treatment and prevention of lymphoedema, in marked improvements in the lymphoedema, and in reduced stigma and discrimination. The care package was found to be acceptable to patients, health professionals and decision makers. The barriers to integrated care were unrealistic patient expectations, inadequate dissemination across health workers, and poor transportation access. Health professionals, decision makers and patients believed the integrated lymphoedema care package to be scalable and sustainable. Conclusion The integrated holistic care package was found to be acceptable to patients, health professionals and decision makers. We recommend its scale-up to other endemic districts

Household crowding, social mixing patterns and respiratory symptoms in seven countries of the African meningitis belt.

OBJECTIVES: To describe the variation in household crowding and social mixing patterns in the African meningitis belt and to assess any association with self-reported recent respiratory symptoms. METHODS: In 2010, the African Meningococcal Carriage Consortium (MenAfriCar) conducted cross-sectional surveys in urban and rural areas of seven countries. The number of household members, rooms per household, attendance at social gatherings and meeting places were recorded. Associations with self-reported recent respiratory symptoms were analysed by univariate and multivariate regression models. RESULTS: The geometric mean people per room ranged from 1.9 to 2.8 between Ghana and Ethiopia respectively. Attendance at different types of social gatherings was variable by country, ranging from 0.5 to 1.5 per week. Those who attended 3 or more different types of social gatherings a week (frequent mixers) were more likely to be older, male (OR 1.27, p<0.001) and live in urban areas (OR 1.45, p<0.001). Frequent mixing and young age, but not increased household crowding, were associated with higher odds of self-reported respiratory symptoms (aOR 2.2, p<0.001 and OR 2.8, p<0.001 respectively). A limitation is that we did not measure school and workplace attendance. CONCLUSION: There are substantial variations in household crowding and social mixing patterns across the African meningitis belt. This study finds a clear association between age, increased social mixing and respiratory symptoms. It lays the foundation for designing and implementing more detailed studies of social contact patterns in this region

Investigation of the effect of different materials on convective heat transfer

Conventionally, the study of convection heat transfer merely focuses on the behavior of air flow without considering the conductive effect of the horizontal flat plate. However, it is expected that the conductive effect of the horizontal plate somewhat affects the air flow temperature across the flat plate. Therefore, it is motivated to study the variation of air flow temperature across different materials of flat plate in various time frame. The materials used in this study are aluminium, stainless steel and cast iron. Infrared camera and FloEFD simulation software are used to measure the upper surface temperature of the flat plate. For forced convection, the study is carried out within the range of 103 £ Re £ 104 and within the range of 1 × 107 £ Ra < 2.2 × 107 for natural convection. Flow velocity of 2.3 m/s, 4.1 m/s and 5.2 m/s are used for the forced convection. The results showed that aluminium plate cools down faster than the other two metal plates used in all scenarios. Stainless steel’s temperature goes down faster compared to cast iron. These results were supported by the fact that aluminium has higher heat transfer rate of other metals. For forced convection, the discrepancies of temperatures between experimental and simulation studies are below 10%, which demonstrates that the results are reasonably acceptable. For natural convection, even though the discrepancies between simulation and experimental results on temperature variations are relatively large, the temperatures varied in similar pattern. This indicates that the results are reliable