Volume 12, Issue 4, August 2021

Simulation Based Propulsion Evaluation of Deployed J-2X Nozzle

Kashif Marjan, Mukkarum Husain

Studio360 Learning
Institute of Space Technology, Pakistan

Abstract- Area ratio of convergent-divergent nozzle plays a vital role in its performance and structural integrity. Nozzle thrust highly depends upon the expansion of gases in the divergent section. Expansion of gases depends upon the area ratio and outside atmospheric pressure. Atmospheric pressure decreases with altitude and therefore a nozzle design for sea level cannot perform optimally at higher altitudes. Altitude compensation nozzles are therefore used to overcome this problem because they work competently at the range of altitude. A variety of altitude compensation nozzles exist, and an extendable nozzle is one of them. Design and analysis of these nozzles is a cyclic process and requires a number of design iterations. The J-2 rocket engine was developed by Rocketdyne and used as an upper stage propulsion system. Extension of the nozzle was then developed and mounted to the basic J-2 nozzle exit to extend its area ratio up to 55:1. The extended J-2 nozzle is known as the J-2X nozzle, and it is an altitude compensating nozzle. The present work investigates the flow physics inside of the J-2 and J-2X nozzles. Computational Fluid Dynamics (CFD) is a numerical tool frequently used for flow prediction and investigation. In the present study, CFD computations are carried out for J-2 and J-2X nozzles. The gain in the thrust for altitude compensating nozzle has been computed. Results are encouraging and depicting the benefit of the nozzle extensions. Improvement in the thrust of altitude compensating nozzle is considerable, but at the same time the weight of the engine is increased. A comparative study between the gain in the thrust and an increase in the weight would be carried out in the future.

Keywords- Altitude Adaptive Nozzle, J-2 Rocket Engine, Extendable Rocket Nozzle and Convergent-Divergent Nozzle

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Evaluation of FARC Multi-action Thresher for Finger Millet Threshing

Gelgelo Kibi, Kamil Ahimad, Mekibab Alamayo

Oromia Agricultural Research Institute, Bako Agricultural Engineering Research Center, P.O.Box 07, West Shoa, Bako

Abstract- Finger millet is a cereal crop grown in most parts of Ethiopia, used for food, in different forms and as an input in preparing traditional alcoholic drinks in some areas. The traditional methods of finger millet threshing are the only method available in most parts of the country, including the major producer western part of Oromia. Hence, this activity is aimed to evaluate an engine powered smaller crops and spice Grains multi-action thresher for finger millet threshing then determine baseline data for modification/development of thresher for the crop. The experimental was conducted in a split- plot design having drum speeds (V1 = 600rpm, V2= 700rpm and V3 = 800rpm) in main plots and concave clearance (20 and 25mm) in sub-plots with three replications as block. The maximum threshing capacity of 82.74 kg/hr was recorded at combination effect 800 rpm and 27 mm drum speed and concave clearance respectively. At this optimum threshing capacity, cleaning efficiency, percentage of loss and threshing efficiency is 48.81, 7.14 and 93.81% respectively. Based on the results obtained, regarding to performance indices like low threshing capacity and cleaning efficiency and to reduce percentage of loss, it is recommended that machine requires a modification.

Keywords- Evaluation, Finger Millet and Threshing

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A Constructive eHealth Model for Population-based Chronic Diseases Management: An Experimental Study for a Randomized Sample Trial

Anam Shahzadi and M. Junaid Arshad

Department of Computer Science, UET, Lahore

Abstract- Different health systems are used in private and some public hospitals in Pakistan. Some hospitals have started to use the electronic health system but not completely implemented. Mostly the hospitals are dependent on paper-based record keeping. The systems are not completely implemented and mainly are developed for hospital management and not for individual users. The system intended in this study is developed to make it patient-centric, providing individuals the self-management support in a secure, cost-effective, time-efficient and usable form and also facilitates hospitals to manage information by overcoming maximum barriers affecting health system. There are some chronic diseases that need more attention of physicians than normal patient. There is a communication gap between patients and doctors. Often patients from distant areas are not able to come in the clinic in case of emergency, this may cause serious threat to the patient’s health. A constructive electronic health model covering major domain of eHealth like EHR for individual users to maintain their medical record, which graphically represents the behavior of diseases and patient health status by providing continuous monitoring at patient level and a chat system to overcome communication gap between doctors and patients (a proactive solution for self-management support of patients) was developed. The system was tested through black box testing technique and conformance testing. A post evaluation analysis was also conducted through two methods including System Usability Scale and expert and doctors review.

Keywords- eHealth, mHealth, EHR, EMR and Chronic Diseases

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Modification and Evaluation BakoTeff Thresher to Tractor PTO Operation

Gelgelo Kibi

Oromia Agricultural Research Institute, Bako Agricultural Engineering Research Center, P.O. Box 07, West Shoa, Kenya

Abstract- Commonly available teff threshers are engine driven, convectional drum type and primarily adapted to thresh teff only. The existing machine has eight long beaters bar, this cause un harmonized the force distribution system resulting in high increased vibration stresses, fixed concave that is only used for teff and less active threshing area. So to overcome the problems of existing teff thresher, this study was initiated with the objectives modify and evaluated the teff thresher machine to tractor PTO operation. Three levels of drum speed 700, 750 and 800rpm and 30Kg/min feeding rate were used to evaluate the performance of the machine at two different districts (Ambo and Gobu Sayo) of teff produce. Performance parameters such as threshing capacity (TC, Kg/hr), cleaning Efficiency (CE, %), and threshing loss (TL, %) were used to review capable achievement of the modified thresher. Based on the results obtained, the grand mean threshing capacity, cleaning Efficiency and threshing loss of 549.88Kg/, 92.68% and 4.18% is recorded for the adapted prototype; respectively. As compared to the previous thresher the modified one had more than 150 Kg/hr threshing capacity. Fuel consumption of 40lit was recorded for threshing 31.5kun of teff at Ambo district. Any users can used 750rpm drum speed in order to get high values of threshing capacity (572.13Kg/hr), cleaning efficiency (94.37%) and minimum threshing loss (2.62%) for any grain straw ratio of teff.

Keywords- Grain Straw Ratio, Modify, Performance and Threshing

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