scholarly journals Analysis and Testing of a Natural Convection Solar Dryer for the Tropics

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
A. O. Adelaja ◽  
B. I. Babatope

Solar dryers are imperative for the tropical and sub-Saharan African countries, which are faced with the duo challenges of inadequate electrical energy supply, which has severely limited the application of conventional refrigeration as a means of preservation of agricultural produce, and the need to make produce competitive in the international market. In this study, a cost-effective natural convection solar dryer was developed; the thermal and drying analyses were done and tested to obtain some performance evaluation parameters for the system in order to examine its efficiency and effectiveness by drying some plantain fillets. The collector and system efficiencies are found to be 46.4% and 78.73%, respectively, while a percentage moisture removal of 77.5% was achieved at the 20th hour in order to give final moisture contents of 15.75% in the product, which still maintained its integrity. With a cost of about $195.00, it has been affordable for the small- and medium-scale enterprises as well as for private use in domestic applications.

Author(s):  
Swathi Kumar ◽  
Richard Blanchard

Around 14% of the global population does not have access to electricity. About 95% of those are living in rural Sub-Saharan Africa. Often in these regions, diesel generators are the only source of electricity. The operating cost of these diesel generators is high. However, solar and wind energy are available in most of African countries. This study presents the analysis of designing an off-grid hybrid system with a wind turbine, PV, diesel generator, and battery to power a hospital, school, and 200 household village in four locations across Somalia. The research investigated the availability of wind-solar resources in selected locations. Designing of the system and economic-technical calculations were performed using HOMER. The selection of the optimum design was based on the Cost of Electricity and Net Present Cost. The results show that for Kabaal and Ceel Buur, a WT-PV-DG-Battery is the optimal system as the wind resource in these regions is high. For Saakov and Baki, a PV-DG-Battery system proves to be optimum as the wind resource is limited here. The study also evaluated the control strategy and proved that combined dispatch was the most cost-effective for these locations. The study concluded that hybrid systems are more economical than diesel systems.


2021 ◽  
Vol 8 (2) ◽  
pp. 135-138
Author(s):  
TH BIDYALAKSHMI DEVI ◽  
YOGESH B KALNAR

A sensor based solar dryer was designed to control the drying environment for precision drying of agricultural produce. The system entirely used solar energy utilizing both thermal and electrical effect. Paraffin wax (PCM) was used for storage of thermal energy whereas solar battery was used to store the electrical energy. Hot air blower was also provided to supply heat when there is less or no solar radiation. Temperature sensors were provided to control the environment of drying chamber. The exhaust fan started operating depending on the set temperature and thus control the drying environment. Load cells were provided below each tray to measure the dry weight. The drying chamber was made of mild steel with glass wool insulation. The capacity of the designed dryer was 10-15 kg with 6 trays. The designed dryer has target temperature of 55-60oC.


Author(s):  
Nikolay S. Shulaev ◽  
◽  
Valeriya V. Pryanichnikova ◽  
Ramil R. Kadyrov ◽  
Inna V. Ovsyannikova ◽  
...  

The most essential scientifific and practical task in the area of ecological safety of pipelines operation is the development and improvement of methods of purifification and restoration of oil-contaminated soils. One of the most effificient and cost effective methods is electrochemical purifification, that does not require the use of expensive chemical reagents and soil excavation. However, the consideration of non-uniform contamination of various soil sections is required. The article examines the features of the organization and technological infrastructure for electrochemical purifification of non-uniformly contaminated soils when using a single electrical energy source, a method for calculating the design parameters of the corresponding installation is proposed. Effificient purifification of non-uniformly contaminated soil when using a specifified voltage is possible through the use of different-sized electrodes. For each soil type, the amount of transmitted electric charge required for soil purifification is determined by the concentration of the contaminant. Allocation of cathodes and anodes as parallel batteries and their connection using individual buses is an effective and energy-effificient solution, since an almost-uniform electric fifield is created in an inter-electrode space, thus allowing the reduction of the interelectrode resistance of the medium.


2020 ◽  
Author(s):  
Ngozi A Erondu ◽  
Sagal A Ali ◽  
Mohamed Ali ◽  
Schadrac C Agbla

BACKGROUND In sub-Saharan Africa, underreporting of cases and deaths has been attributed to various factors including, weak disease surveillance, low health-seeking behaviour of flu like symptoms, and stigma of Covid-19. There is evidence that SARS-CoV-2 spread mimics transmission patterns of other countries across the world. Since the Covid-19 pandemic has changed the way research can be conducted and in light of restrictions on travel and risks to in-person data collection, innovative approaches to collecting data must be considered. Nearly 50% of Africa’s population is a unique mobile subscriber and it is one of the fastest growing smart-phone marketplaces in the world; hence, mobile phone platforms should be considered to monitor Covid-19 trends in the community. OBJECTIVE We demonstrate the use of digital contributor platforms to survey individuals about cases of flu-like symptoms and instances of unexplained deaths in Ethiopia, Kenya, Nigeria, Somalia, and Zimbabwe. METHODS Rapid cross-sectional survey of individuals with severe flu and pneumonia symptoms and unexplained deaths in Ethiopia, Kenya, Nigeria, Somalia and Zimbabwe RESULTS Using a non-health specific information platform, we found COVID-19 signals in five African countries, specifically: •Across countries, nearly half of the respondents (n=739) knew someone who had severe flu or pneumonia symptoms in recent months. •One in three respondents from Somalia and one in five from Zimbabwe respondents said they knew more than five people recently displaying flu and/or pneumonia symptoms. •In Somalia there were signals that a large number of people might be dying outside of health facilities, specifically in their homes or in IDP or refugee camps. CONCLUSIONS Existing digital contributor platforms with local networks are a non-traditional data source that can provide information from the community to supplement traditional government surveillance systems and academic surveys. We demonstrate that using these distributor networks to for community surveys can provide periodic information on rumours but could also be used to capture local sentiment to inform public health decision-making; for example, these insights could be useful to inform strategies to increase confidence in Covid19 vaccine. As Covid-19 continues to spread somewhat silently across sub-Saharan Africa, regional and national public health entities should consider expanding event-based surveillance sources to include these systems.


2014 ◽  
Vol 2 (2) ◽  
Author(s):  
Shuaib Lwasa

Africa’s urbanization rate has increased steadily over the past three decades and is reported to be faster than in any other region in the world . It is estimated that by 2030, over half of the African population will be living in urban areas . But the nature of Africa’s urbanization and subsequent form of cities is yet to be critically analyzed in the context of city authorities’ readiness to address the challenges . Evidence is also suggesting that urbanization in African countries is increasingly associated with the high economic growth that has been observed in the last two decades . Both underlying and proximate drivers are responsible for the urbanization, and these include population dynamics, economic growth, legislative designation, increasing densities in rural centers, as well as the growth of mega cities such as Lagos, Cairo and Kinshasa, that are extending to form urban corridors . With the opportunities of urbanization in Sub–Saharan Africa, there are also challenges in the development and management of these cities . Those challenges include provision of social services, sustainable economic development, housing development, urban governance, spatial development guidance and environmental management, climate change adaptation, mitigation and disaster risk reduction . The challenge involves dealing with the development and infrastructure deficit, in addition to required adaption to and mitigation of climate change . This paper examines the current state of urban management in Africa .


Having broadly stabilized inflation over the past two decades, many policymakers in sub-Saharan Africa are now asking more of their monetary policy frameworks. They are looking to avoid policy misalignments and respond appropriately to both domestic and external shocks, including swings in fiscal policy and spikes in food and export prices. In many cases they are finding current regimes—often characterized as ‘money targeting’—lacking, with opaque and sometimes inconsistent objectives, inadequate transmission of policy to the economy, and difficulties in responding to supply shocks. At the same time, little existing research on monetary policy is targeted to low-income countries. What do we know about the empirics of monetary transmission in low-income countries? (How) Does monetary policy work in countries characterized by a huge share of food in consumption, underdeveloped financial markets, and opaque policy regimes? (How) Can we use methods largely derived in advanced countries to answer these questions? And (how) can we use the results to guide policymakers? This book draws on years of research and practice at the IMF and in central banks from the region to shed empirical and theoretical light on these questions and to provide practical tools and policy guidance. A key feature of the book is the application of dynamic general equilibrium models, suitably adapted to reflect key features of low-income countries, for the analysis of monetary policy in sub-Saharan African countries.


Author(s):  
Peter Kayode Oniemola ◽  
Jane Ezirigwe

To achieve universal energy access will attract huge capital investments. If sub-Saharan Africa is to realize anything close to the ambitious goals set for its energy access, then new actors, innovative funding mechanisms and sustainable technologies will have to be attracted. Finance is needed for activities such as rural electrification, clean cooking facilities, diesel motors and generators, other renewable energy technologies, oil and gas infrastructures, etc. Finance is also needed in research and development of suitable technologies and funding options as well as investment in the capacity to formulate and implement sound energy policies. This chapter examines the varied financing options for energy access in sub-Saharan Africa. It argues that with appropriate laws in place and effective mechanism for implementation, African countries can significantly engage private sector financing, international financial institutions and foreign donors. The role of the law here will be in creating an enabling environment for financing.


2019 ◽  
Vol 6 ◽  
Author(s):  
C. Merritt ◽  
H. Jack ◽  
W. Mangezi ◽  
D. Chibanda ◽  
M. Abas

Background. Capacity building is essential in low- and middle-income countries (LMICs) to address the gap in skills to conduct and implement research. Capacity building must not only include scientific and technical knowledge, but also broader competencies, such as writing, disseminating research and achieving work–life balance. These skills are thought to promote long-term career success for researchers in high-income countries (HICs) but the availability of such training is limited in LMICs. Methods. This paper presents the contextualisation and implementation of the Academic Competencies Series (ACES). ACES is an early-career researcher development programme adapted from a UK university. Through consultation between HIC and LMIC partners, an innovative series of 10 workshops was designed covering themes of self-development, engagement and writing skills. ACES formed part of the African Mental Health Research Initiative (AMARI), a multi-national LMIC-led consortium to recruit, train, support and network early-career mental health researchers from four sub-Saharan African countries. Results. Of the 10 ACES modules, three were HIC-LMIC co-led, four led by HIC facilitators with LMIC training experience and three led by external consultants from HICs. Six workshops were delivered face to face and four by webinar. Course attendance was over 90% and the delivery cost was approximately US$4500 per researcher trained. Challenges of adaptation, attendance and technical issues are described for the first round of workshops. Conclusions. This paper indicates that a skills development series for early-career researchers can be contextualised and implemented in LMIC settings, and is feasible for co-delivery with local partners at relatively low cost.


Author(s):  
Emmanuel Nii-Boye Quarshie ◽  
Samuel Kofi Odame

AbstractSuicidal ideation is a critical risk for attempted suicide and eventual suicide. Little is known about suicidal ideation among rural adolescents in most sub-Saharan African countries. We aimed to estimate the 12-month prevalence of suicidal ideation and to describe some of the common and gender-specific associated factors among in-school adolescents in rural Ghana. We conducted a cross-sectional survey involving a random sample of 1101 in-school adolescents aged 10–19 years in a rural district in Eastern Ghana. The Suicidal Behavior Questionnaire-Revised was used to assess suicidal ideation. Overall, 25.1% participants (95% CI = 22.5–27.7), representing 28.3% females (95% CI = 24.7–32.2) and 21.5% males (95% CI = 18.0–25.2) reported suicidal ideation during the previous 12 months. Females who experienced personal and interpersonal adversities mainly outside the family context were likely to report suicidal ideation, while suicidal ideation among males was associated with conflict with parents. Regardless of gender, adolescents who reported exposure to a friend’s attempted suicide were about two times more likely to report suicidal ideation. The prevalence of suicidal ideation among adolescents in rural Ghana compares with in-school estimates from other countries within sub-Saharan Africa, but also underscores the need for targeted and universal prevention programmes and intervention efforts to mitigate the potential transition from suicidal ideations to suicidal attempts and eventual deaths by suicide among rural adolescents.


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