Natural Radioactivity Levels and Radiogenic Heat Production in River Sediments from Gulu and Amuru Districts, Northern Uganda

The activity concentrations (AC) of 238U, 232Th and 40K in sediments from Gulu and Amuru districts, Uganda were determined using NaI(Tl) detector at Physics Department, Makerere University, Kampala to obtain; radioelement concentrations (RC), radiogenic heat production (RHP) and associated heat flow (Hf). The AC varied from (36.1 ± 2.3 - 261.2 ± 15.3) for 238U, (97.4 ± 13.5 - 334.2 ± 36.6) for 232Th, and (47.5 ± 3.9 - 1442.3 ± 58.9) Bq kg-1 for 40K, with averages of 89.6 ± 6.3, 168.6 ± 17.9, and 275.4 ± 14.0 Bq kg-1, respectively, above the world limits of 35, 30, and 400 Bq kg-1, for 238U, 232Th and 40K. The RC varied from (2.9 ± 0.2 - 20.8 ± 1.2) ppm for 238U, (23.9 ± 3.3 - 82.0 ± 9.2) ppm for 232Th, and (0.2 ± 0.01 - 3.2 ± 0.1) % for 40K, with averages of 7.1 ± 0.5 ppm, 41.3 ± 4.3 ppm, and 1.1 ± 0.05%, respectively. The 238U and 232Th averages were above the Earth’s crust values of 3 ppm and 12 ppm, respectively. The 40K average is below the Earth’s crust value of 2.33%.  The RHP varied from (2.5 ± 0.6 - 10.2 ± 2.6) µW m-3 with an average of 4.5 ± 1.1 µW m-3, above the world average of 4µW m-3. High and moderate RHP, each account for 50% of the samples. The overall RHP mainly depended on 232Th amounts, with 60% contribution. However, an increase in the AC of 238U, 232Th and 40K reflected the integrated effect of RHP. The Hf varied from (19.6 ± 1.0 - 80.0 ± 4.0) mW m-2 with an average of 35.3 ± 1.8 mW m-2. The high RHP and Hf values indicates feasibility for geothermal exploration. This calls for further studies to validate these findings

Thermal Performance of Selected Oils in Uganda for Indirect Solar Domestic Cooking Applications

This study experimentally evaluated the thermal performance of selected oils in Uganda for indirect solar domestic cooking applications. The oil samples used were refined sunflower oil, refined palm oil and thermia B. These oils are locally available in Uganda. Thermal stratification, energy and exergy analysis were performed for each oil to determine their suitability for Thermal Energy Storage (TES) using a thermosiphon principle. The results showed that thermal stratification of refined sunflower oil was higher as compared to refined palm oil and thermia B during the first one hour. The stored energy and exergy for refined sunflower oil was generally higher than that of refined palm oil and thermia B. The thermal performance of refined sunflower oil was comparable to that of refined palm oil which was better than that of thermia B.Keywords: Thermosiphon; thermal stratification; energy; exergy; oi

The Primordial Radionuclides Activity Concentrations and Associated Minerals in Rocks from Selected Quarries in Northern Uganda

The primordial radionuclides (PR) activity concentrations and associated minerals in 20 rock samples from Gulu and Amuru district quarries were determined using Na (Tl) gamma ray spectrometer and Transmitted Light Microscope (TLM). These were carried out at Physics and Geology Departments of Makerere University, Kampala in Uganda. The PR activity concentrations, the gamma dose rates, and the radiological hazard indices were all determined to assess the radiological hazards and risks of the exposure on the quarry workers and on the inhabitants. The minerals were obtained to determine whether minerals containing PR were highly radioactive. The computed PR activity concentrations from the five quarries ranged from 4.1 ± 1.7 to 207.6 ± 6.5 for 238U, 7.0 ± 2.0 to 452.0 ± 2.3 for 232Th, and 8.6 ± 2.0 to 2055.4 ± 73.1 Bq kg-1 for 40K, respectively with averages of 57.1 ± 4.7, 122.3 ± 11.1, and 914.2 ± 30.3 Bq kg-1. These values were found to be above the world limit of 33.0, 45.0 and 420.0 Bq kg-1 by 1.7, 2.7, and 2.2 factors. The computed average values of absorbed gamma dose rates (D), annual effective dose equivalent outdoor (Eo), excess lifetime cancer risk (ELCR), radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin) and gamma index (I) for the five quarries were 134.58 ± 10.13 nGy h-1, 0.34 ± 0.03 mSv yr-1, 1.07 ± 0.09 x 10-3, 294.08 ± 17.88 Bq kg-1, 0.80 ± 0.06, 0.93 ± 0.05 and 1.35 ± 0.09, respectively. The computed average values of D, Eo and ELCR for the five quarries were above the world limit by factors of 2.2, 4.9, and 3.7, respectively. Therefore, quarry workers and the inhabitants were exposed to PR hence significant health risks associated with induced cancer and gene mutation. However, average values of Raeq, Hex, and Hin were found to be below the world limit except for one of the quarry sites. Although the studied rocks could be used as building materials without causing external diseases and respiratory infections, the average value of, I, showed that studied rocks should be used in moderation to limit the radiological hazards except for Palukere rocks. Mineralogical analyses has also shown the presence of quartz, potassium feldspar, plagioclase, biotite, muscovite, and opaque minerals. Quartz was the major mineral while the rest were accessories. The results of this study could be used by different institutions such as Uganda Atomic Energy Council (AEC) that protects the environment from dangers resulting from ionizing radiation. This body could assist to advise quarry workers on good practices. The National Environmental Management Authority (NEMA) that controls environmental systems should ensure that Gulu and Amuru districts work in line with set principles on environment, and where necessary to enforce the quarry by-laws and ordinances. To urge the Directorate of Geological Survey and Mines (DGSM) to also conduct geological studies for valuable radioactive minerals in the study areas of Gulu and Amuru districts. The Uganda Ministry of Health (MoH) experts could also carry out additional studies to establish the correlation of cancer infections and quarry works. This would inform the government on corrective measures that protects the population of the region.

Performance Investigations of the Charging and Discharging Processes in a 3-Tank Thermal Energy Storage System

The paper presents a 3 tank thermal energy storage system. The system consists of cold oil reservoir, heat storage tank, and a residual drainage tank. Cold oil flows by gravity into a heating chamber and after being heated to the required temperature, a mechanical thermostat opens allowing the hot oil to flow into a heat storage tank. The storage tank was discharged through the cooking unit by boiling 0.5 litres of water. The used oil flowed by gravity to the drainage tank. The discharge flow rates of 0.5, 2.1, 2.8 and 6.5 g/s were considered. A charging efficiency of 51.3% and overall discharging efficiency range of 15.3 34.7% were achieved. Charging efficiency increased when the source was embedded in the storage tank. The instantaneous discharge power had a peak value for each flow rate. The adopted cooking unit had a thermal transfer efficiency range of 34.7 57.6%. A method for sizing oil based TES systems was proposed and illustrated based on the obtained discharge results. Keywords:     3-tank, sizing, discharging, efficiency, thermal energ

Effect of different organic substrates on reproductive biology, growth and offtake of the African night crawler earthworm (Eudrilus eugeniae)

Rapid growth and high fecundity of E. eugeniae makes it a commercial vermicomposting agent. The worm is also a rich protein source (50-70%CP) in livestock diets. The major question, however, is how do we promote earthworm production as a strategy for ecological livestock intensification and integration with crops through earthworm domestication as a source of protein and vermicompost. Reproduction characteristics, growth and offtake of E. eugeniae were studied using four organic substrates including abattoir waste (AW), cattle manure (CM), soya bean crop residue (SBCR) and a mixture of cattle manure and soya bean crop residue (CM+SBCR) aged for 15 days. Irrespective of the substrate, length and biomass of earthworms increased at a decreasing rate between the 1st and 8th weeks. Clitellum appearance was initiated at 31.5±2.4, 32.8±3.2, 33.7±3.3 and 35.5±2.4 days for AW, CM, CM+SBCR and SBCR, respectively, while cocoon initiation was at 69.0±1.4 (AW), 54.9±2.3 (CM), 51.7±1.7 (CM+SBCR) and 60.0±2.4 (SBCR) days. Organic substrate used affected reproductive biology, growth and offtake of E. eugeniae. Higher survivability, total earthworm biomass accumulation and offtake when cultured on CM and a binary combination of CM + SBCR is an indication that a strategy for sustainable crops-livestock integration can be sparked off by earthworm domestication. Earthworm domestication can be promoted using CM or a combination of (CM+SBCR) as substrate

A ray tracer model for analysis of solar concentrating systems

This study describes a 3D ray tracer model for analysis of a small-scale solar concentrating system where thermal heat is collected for cooking purposes. Emitted sun rays were traced from the source through all reflections until they intercepted with the receiver or were lost. The algorithm of the ray tracer and its implementation in MATLAB is clearly described. The ray tracer was programmed to contribute to the development of small-scale concentrating solar energy systems with integrated heat storage units. The ray tracer was demonstrated for selected cases where continuous reflecting surfaces and flat mirror-tiled surfaces were compared. Off-focus sensitivity analysis was shown and this could provide guidelines for the required solar tracking accuracy. The flux distribution on the absorber was analysed and found to be concentrated on a small area on the target for continuous reflecting surfaces and having high intensities. However, for reflectors with mirror tiles, an elongated image was formed centred on the focal point with low intensities. Small misalignment of the reflector in the order 0.2° had minimal impact on the interception ratio, but any further increase in the tracking errors caused a sudden drop in the interception ratio to zero. Results showed that there is close agreement in flux distribution and the tracking error impact on interception ratio, when compared with the literature. This model could be a useful tool when designing the reflection and absorption components of solar concentrators for complex systems with several components in a non-symmetric 3D arrangement

Evaluation of the surveillance system in Kiryandongo Refugee Settlement, Kiryandongo District, Uganda, April 2017

Introduction: Integrated Disease Surveillance and Response (IDSR) involves surveillance of priority diseases and conditions, and is implemented in many African countries, including Uganda. During humanitarian emergencies, public health surveillance systems such as IDSR may face challenges. We assessed the capacity of health facilities (HF) in Kiryandongo District, a district with a large and recent refugee influx, to perform IDSR core functions. Methods: We visited five HF serving refugee settlements and one serving the host community. We interviewed HF in-charges, surveillance Focal Persons, and District Health Team (DHT) members about their capacity to perform IDSR. We reviewed paper-based forms in IDSR to evaluate system attributes during April 2016-March 2017. We determined the average weekly health Management Information System (HMIS) reporting rate for weeks 1-13 of 2017. Results: All HFs were well-staffed. However, half of the 12 suspected disease outbreaks reported in the past year were not investigated. The average weekly reporting rate was 79% (target: 80%). Barriers to IDSR included absence of standard case definition booklets (50%) and updated paper forms (67%), incomplete filling of registers, and inadequate data analysis (33%). The District Epidemic Preparedness and Response Committee (DEPRC) was non-functional. Conclusion: There was low capacity of the district to conduct IDSR, which could have slowed detection of and response to outbreaks. We recommended IDSR refresher trainings in two-year cycles and supplying guidelines to all HFs. The DEPRC and DHT should be strengthened through funding, regular meetings, and supplies of essential commodities

Dynamic model of a small scale concentrating solar cooker with rock bed heat storage

This study presents a dynamic model for a concentrating solar energy collector with an integrated rock bed heat storage system. The model is based on numerical integration of a set of conservation equations for mass, momentum and energy of the heat carrier, the rock pebbles and the walls. The heat carrier is compressible air. Numerical solutions are implemented based on implicit time integration without iterations. Stability problems at large time steps do not occur but the accuracy is reduced. The model predicts pressure, velocity, density and temperatures of the fluid, rock bed and wall in time and along the bed. The model is validated with experimental results in a laboratory setting on temperature profiles during charging and discharging of rock bed heat storage. The intention is that the model shall serve as a computational tool for upscaling of air based concentrating solar energy systems with rock bed heat storage units

Collaborative autoethnography and reclaiming an African episteme: investigating “customary” ownership of natural resources

Collaborative autoethnography can function as a means of reclaiming certain African realities that have been co-opted by colonial epistemes and language. This can be significant in very concrete ways: northern Uganda is suffering a catastrophic loss of tree cover, much of which is taking place on the collective family landholdings that academia and the development sector have categorized as “customary land.” A collaboration by ten members of such landholding families, known as the Acholi Land Lab, explores what “customary ownership” means to them and their relatives, with a view to understanding what may be involved in promoting sustainable domestic use of natural resources, including trees

Impact of early continuous positive airway pressure in the delivery room (DR-CPAP) on neonates < 1500 g in a low-resource setting: a protocol for a pilot feasibility and acceptability randomized controlled trial

Background Preterm birth is the leading cause of childhood mortality, and respiratory distress syndrome is the predominant cause of these deaths. Early continuous positive airway pressure is effective in high-resource settings, reducing the rate of continuous positive airway pressure failure, and the need for mechanical ventilation and surfactant. However, most deaths in preterm infants occur in low-resource settings without access to mechanical ventilation or surfactant. We hypothesize that in such settings, early continuous positive airway pressure will reduce the rate of failure and therefore preterm mortality. Methods This is a mixed methods feasibility and acceptability, single-center pilot randomized control trial of early continuous positive airway pressure among infants with birthweight 800-1500 g. There are two parallel arms: (i) application of continuous positive airway pressure; with optional oxygen when indicated; applied in the delivery room within 15 min of birth; transitioning to bubble continuous positive airway pressure after admission to the neonatal unit if Downes Score ≥ 4 (intervention), (ii) supplementary oxygen at delivery when indicated; transitioning to bubble continuous positive airways pressure after admission to the neonatal unit if Downes Score ≥ 4 (control). A two-stage consent process (verbal consent during labor, followed by full written consent within 24 h of birth) and a low-cost third-party allocation process for randomization will be piloted. We will use focus group discussions and key informant interviews to explore the acceptability of the intervention, two-stage consent process, and trial design. We will interview healthcare workers, mothers, and caregivers of preterm infants. Feasibility will be assessed by the proportion of infants randomized within 15 min of delivery; the proportion of infants in the intervention arm receiving CPAP within 15 min of delivery; and the proportion of infants with primary and secondary outcomes measured successfully. Discussion This pilot trial will enhance our understanding of methods and techniques that can enable emergency neonatal research to be carried out effectively, affordably, and acceptably in low-resource settings. This mixed-methods approach will allow a comprehensive exploration of parental and healthcare worker perceptions, experiences, and acceptance of the intervention and trial design. Trial registration The study is registered on the Pan African Clinical Trials Registry (PACTR) PACTR202208462613789. Registered 08 August 2022. https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=23888