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Proof of Concept MFD Optimization of the Aftbody Geometry of Axisymmetric Slender Body Based on Wave Drag Considerations

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Journal of Mechanics Engineering and Automation 2013年第8期3卷 473-490页

作者： harijono djojodihardjo Eddy Prijono Department of Aerospace Engineering Faculty of Engineering University Putra Malaysia Nurtanio University

A comprehensive, universally valid, elegant and yet simple method to design slender axisymmetric body of minimum wave drag in transonic and supersonic flows is developed. Computational aerodynamics is also used as a tool for numerical experiments in gaining physical understanding of the drag mechanism due to the geometry of the aftbody, such as the correlation between wave drag and wave distribution of the aftbody geometry. The method utilizes MFD （modified feasible direction） based optimization program, along with the linear slender body aerodynamics, for its elegance and generic optimization convenience. The efforts are focused on inviscid flow. A practical method of reducing the wave drag of a given body is developed for both bodies with pointed end and with base area, using shock wave generator at a particular location on the aftbody. The results show that the MFD optimization program can be effectively utilized in an aerodynamic optimization problem.

关键词： Aerodynamics computational fluid dynamics optimization slender body transonic flow supersonic flow axisymmetricflow shock-generation.

Conceptual Design and Aerodynamic Study of Joined-Wing Business Jet Aircraft

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Journal of Mechanics Engineering and Automation 2013年第5期3卷 263-278页

作者： harijono djojodihardjo Kim Em Foong Department of Aerospace Engineering Faculty of Engineering Universiti Putra Malaysia Serdang 43400 Selangor Malaysia

The concept of joined-wing aircraft with nonplanar wings as conceived and patented by Wolkovitch is attractive due to various advantages such as light weight, high stiffness, low induced drag, high trimmed CLmax, reduced wetted area and parasite drag and good stability and control, which have been supported by independent analyses, design studies and wind tunnel tests. With such foreseen advantages, the present work is carried out to design joined-wing business-jet aircraft and study and investigate its advantages and benefits as compared to the current available conventional business jet of similar size, passenger and payload capacity. In particular, the work searches for a conceptual design of joined-wing configured business-jet aircraft that possesses more superior characteristics and better aerodynamic performance in terms of increased lift and reduced drag, and lighter than the conventional business jet of similar size. Another significant objective of this work is to prove that the added rigidity possessed by the joined wing configuration can contribute to weight reduction.

关键词： Aircraft conceptual design aerodynamic design joined wing box wing.

Kinematic and Aerodynamic Modelling of Bi- and Quad-Wing Flapping Wing Micro-Air-Vehicle

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Advances in Aerospace Science and Technology 2016年第3期1卷 83-101页

作者： harijono djojodihardjo Alif Syamim S. Ramli Surjatin Wiriadidjaja Azmin Shakrine Mohd Rafie Aerospace Engineering Department Faculty of Engineering Universiti Putra Malaysia Serdang Malaysia

A generic approach to model the kinematics and aerodynamics of flapping wing ornithopter has been followed, to model and analyze a flapping bi- and quad-wing ornithopter and to mimic flapping wing biosystems to produce lift and thrust for hovering and forward flight. Considerations are given to the motion of a rigid and thin bi-wing and quad-wing ornithopter in flapping and pitching motion with phase lag. Basic Unsteady Aerodynamic Approach incorporating salient features of viscous effect and leading-edge suction are utilized. Parametric study is carried out to reveal the aerodynamic characteristics of flapping bi- and quad-wing ornithopter flight characteristics and for comparative analysis with various selected simple models in the literature, in an effort to develop a flapping bi- and quad-wing ornithopter models. In spite of their simplicity, results obtained for both models are able to reveal the mechanism of lift and thrust, and compare well with other work.

关键词： Bi-Wing Ornithopter Flapping Wing Aerodynamics Flapping Wing Ornithopter Micro Air Vehicle Quad-Wing Ornithopter

Analysis of Antibiotic Usage in Critical COVID-19 Patients with Secondary Infections

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Journal of Biosciences and Medicines 2022年第12期10卷 122-133页

作者： Widyati Widyati Pandu harijono Syahrul Tuba Dr. Ramelan Navy Hospital Surabaya Indonesia Faculty of Military Pharmacy The Republic of Indonesia Defense University Sentul Indonesia Medical Faculty of Hang Tuah University Surabaya Indonesia

Background: Infrequent data exist on the frequency of bacterial co-infections and secondary infection among COVID-19-infected patients admitted to intensive care units (ICU). Objective: To describe the quantity and the quality of antimicrobial usage in COVID-19 with secondary infection, multiple drug resistance organisms and the outcome of antimicrobial treatment. Methods: This study applies observational design with a cross sectional approach. All the patients with laboratory-confirmed severe COVID-19 pneumonia who were discharged from the Intensive Care Unit (ICU) Dr. Ramelan Navy Hospital from February 1st to June 30th 2022 included. The quantity of antibiotics usage was assessed by counting the Defined Daily Dose (DDD). Result: During the study period, 126 patients were referred to the ICU for COVID-19 with severe pneumonia. There were 70.6% (89 patients) treated with antibiotics and 29.4% (37 patients) untreated with antibiotics. Quantitative analysis of 89 patients revealed that levofloxacin was the most common antibiotic prescribed with 43 DDD, followed by Meropenem and Cefoperazone-Sulbactam, which were 17.76 DDD and 16.87 DDD, respectively. Meanwhile, qualitative analysis resulted in 81 antibiotics (43.55%) being used appropriately. No indications of the use of antibiotics were found in 53 antibiotics (28.49%). Klebsiella pneumonia was the main pathogen identified in the blood, sputum. While E. Coli was found to be the main pathogen in urine. Conclusion: A high death rate in patients treated with antibiotics compared to patients not treated with antibiotics.

关键词： Bacterial Coinfection Critical COVID-19 Intensive Care Unit Antibiotics Pneumoniae