Case Report
Evaluation of Propellant Slosh Effects and Baffle Requirements in a Hybrid Rocket Oxidizer Tank
Gedlu Solomon*
,
Yishak Tamiru
Issue:
Volume 7, Issue 3, September 2026
Pages:
84-95
Received:
3 June 2026
Accepted:
12 June 2026
Published:
17 July 2026
DOI:
10.11648/j.rd.20260703.11
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Abstract: This paper investigates the necessity of incorporating internal baffles in the oxidizer tank of a vertically launched hybrid rocket employing a regressive fuel grain configuration. The study begins with a review of potential sources of rocket instability, with particular emphasis on propellant slosh and its influence on vehicle stability throughout the flight mission. A systems engineering methodology is adopted to define the mission objectives and establish the corresponding design requirements. These requirements are subsequently decomposed into lower-level requirements and verified through analytical methods to ensure compliance with the overall system objectives. The propulsion system performance is evaluated using NASA Chemical Equilibrium with Applications (CEA) software, considering Hydroxyl-Terminated Polybutadiene (HTPB) as the fuel and Nitrous Oxide (N2O) as the oxidizer at an oxidizer-to-fuel ratio of 8 and a combustion chamber pressure of 30 bar. To characterize the operational environment, the NRLMSIS atmospheric model is employed to obtain atmospheric temperature, air density, and gravity data for 5 May 2026 over an altitude range from sea level to 20 km with 1 km intervals. Based on the derived requirements, preliminary oxidizer tank design activities are conducted, including tank sizing, material selection, wall-thickness determination, and the definition of internal tank features. The dynamic effects of oxidizer motion during flight are analytically evaluated and compared with the stabilizing forces generated by tank ullage pressure. The results demonstrate that the forces induced by oxidizer slosh are significantly smaller than the available stabilizing forces and therefore have a negligible impact on vehicle stability. Consequently, the study concludes that internal baffles are not required for the proposed oxidizer tank design, enabling a simpler and lighter tank configuration without compromising flight stability.
Abstract: This paper investigates the necessity of incorporating internal baffles in the oxidizer tank of a vertically launched hybrid rocket employing a regressive fuel grain configuration. The study begins with a review of potential sources of rocket instability, with particular emphasis on propellant slosh and its influence on vehicle stability throughout...
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Research Article
On-Farm Performance Evaluation of Koekoek Layers Chicken in West Arsi Zone of Oromia, Ethiopia
Issue:
Volume 7, Issue 3, September 2026
Pages:
96-102
Received:
8 April 2026
Accepted:
1 June 2026
Published:
17 July 2026
DOI:
10.11648/j.rd.20260703.12
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Abstract: This study was conducted with the objective of evaluating the egg production performance and egg quality of Koekoek chicken breed under farmer management conditions with locally formulated rations and determines the economic feasibility. Chickens were managed under a semi-scavenging system and supplemented with a locally formulated diet, except for one household which served as a control (no formulated ration). The ingredients used were maize (35%), soybean (20%), wheat bran (19.5%), noug cake (22%), salt (1.5%), premix (1%), and limestone (1%). Each bird received 90 g of the formulated feed daily. A total of 240 Koekoek chickens (200 pullets and 40 cockerels) were distributed and purposive sampling approach was employed to select 20 smallholder farmers (10 from each district) in collaboration with Development Agents, and Kebele leaders. Results showed that formulated ration feeding improved survival rate and egg production performance. Nagele Arsi had a higher survival rate (95%) compared to Kofele (78%). Egg production per hen per year increased with ration, from 122 to 180 eggs in Kofele and from 183 to 222 eggs in Nagele Arsi. While egg quality parameters (egg length, egg width, and yolk color and shell weight) showed no statistically significant differences, egg weight, albumen weight and shell thickness was improved with formulated ration. Formulated ration improved the economic performance of Koekoek layers under farmer management conditions. Farmers perceived Koekoek chickens as more productive when supplemented, less broody, and resilient to disease and predatory compared to local breeds. The study concludes that locally formulated ration improves egg productivity from 153-201, income and survival of Koekoek layer chickens under smallholder management conditions.
Abstract: This study was conducted with the objective of evaluating the egg production performance and egg quality of Koekoek chicken breed under farmer management conditions with locally formulated rations and determines the economic feasibility. Chickens were managed under a semi-scavenging system and supplemented with a locally formulated diet, except for...
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Review Article
Civic Educators' Comprehension of Citizenship and Its Influence on Civic Engagement in Selected Universities and Secondary Schools in Zambia
Issue:
Volume 7, Issue 3, September 2026
Pages:
103-110
Received:
8 February 2026
Accepted:
20 February 2026
Published:
22 July 2026
DOI:
10.11648/j.rd.20260703.13
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Abstract: This study established the Civic Educators' comprehension of citizenship and its influence on civic engagement in selected universities and secondary schools in Zambia. Using a qualitative research approach and descriptive research design. The target population were lecturers and students at University of Zambia, Kwame Nkrumah University and Chalimbana University. The sample size was 30 participants. Inductive thematic analysis was used to analyse data because themes were strongly linked to data. The findings revealed that lecturers had a comprehensive conception of citizenship. They defined citizenship to comprise rights and duties. This aligns with the definition of citizenship as practice and the communitarian theory of citizenship, that takes into consideration both rights and duties as important aspects of citizenship. The teachers and student teachers conceptualised citizenship in terms of belonging and qualification. This conception emphasized rights over duties as per the liberalist theory of citizenship. The study argued that the participants’ comprehension of citizenship influenced their conception of civic engagement in universities and selected secondary schools in Zambia. The findings of the study recommended the need for enhanced Civic education training and curriculum development to foster meaningful civic engagement and understanding of the concept of citizenship. The study also recommended professional development programmes and relevant curriculum reforms.
Abstract: This study established the Civic Educators' comprehension of citizenship and its influence on civic engagement in selected universities and secondary schools in Zambia. Using a qualitative research approach and descriptive research design. The target population were lecturers and students at University of Zambia, Kwame Nkrumah University and Chalim...
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