Direct design process of aerodynamic profiles using the Joukowsky transformation

This document shows the results of a part of the direct design process of airfoils. The research and design of these geometric shapes are of great relevance for their application in aerodynamic devices, since, if a wing profile with a great aerodynamic fineness is developed, the efficiency of the devices that have this geometric shape will be improved on its wings, propellers, etc. This project started from two analytical processes, the first was to obtain the shape of the wing profiles through the Joukowsky transformation, later the pressure distribution of each aerodynamic profile was obtained through the methodology developed by Theodorsen, the profiles that achieved optimal results were subjected to the third and last analysis in the Qblade software, this software allows to find the angle of attack that produces the maximum aerodynamic fineness, in addition to an approximation to the lift and drag coefficients, in this way several curved and aerodynamic profiles were obtained. Various thicknesses whose aerodynamic fines range between 100 and 250 at the optimum angle of attack.

題目設定引導設計邏輯發展之教學研究

<p>傳統的建築設計課程皆以每學期幾次不同題型的設定，期望在設計操作的反復練習中，幫助操作者探索合適的操作方法並從中建立設計邏輯。設計題目的設定規範了操作的方向與期望的成果，但因設計發展並沒有既定的步驟與方法，常因個人經驗與所選擇設計方式的不同，導致過於感性的思維模式，也造就了理性建築設計教學的挑戰。此研究針對題目設定與設計邏輯的關係，試圖避開操作者可預期的結果，並藉過程中不同階段性的操作設定，試圖建立一種設計邏輯發展的依據。</p> <p>&nbsp;</p><p>Traditionally, architecture design studio requires few exercises per semester for students to practice design method and develop design thinking. As design exercises often direct design approach and also establish expectation of outcome, there is no guaranty procedure or design method to follow in order to achieve the best outcome. Since design development heavily based on experience of operation and choice of approach, sensible thinking process is often involved and sets challenge for rational architectural pedagogy. This research aims to exam the design thinking process of students by setting up specific design exercise to avoid predictable operation process, in order to direct specific design approach according to established guidance for further development. </p> <p>&nbsp;</p>

Optimum sizing of members of truss structures using direct design and a self-adaptive mutationdifferential evolution

Direct design using nonlinear inelastic analysis has been recently enabled for structural design as this approach can directly predict the behaviour of a structure as a whole, which eliminates capacity checks for individual structural members. However, the use of direct design is often accompanied by excessive computational efforts, especially for complicated structural design problems such as optimization or reliability analysis. In this study, we introduce an efficient method for the sizing optimization of truss structures employing nonlinear inelastic analysis for the direct design of structures. The objective function is the total weight of the structure while the strength and serviceability constraints are evaluated with nonlinear inelastic analysis. To save computational cost, an improved differential evolution (DE) algorithm is employed. Compared to the conventional DE algorithm, the proposed method has two major improvements: (1) a self-adaptive mutation strategy based on the p-best method to enhance the balance between global and local searches and (2) use of the multi-comparison technique (MCT) to reduce redundant structural analyses. The numerical results of a 72-bar truss case study demonstrate that the performance of the proposed method has significant advantages over the traditional DE method.

Enhancing Design Features of Asymmetric Spur Gears Operating on a Specified Center Distance Using Tooth Sum Altered Gear Geometry

Asymmetric gears have evolved from the rising demand for power transmission drives with high load-carrying capacity, surface durability, and service life. Direct design and S± profile shifted system are the most common approaches used for enhancing design features by geometry modification in asymmetric gears. This paper aims at establishing asymmetric gear geometry modification using tooth sum alteration for a family of gears running on a specified center distance as a feasible design approach. A complete mathematical treatment of the design approach is provided, and an in-house developed computer program is used for numerical simulation. The paper explores the influence of dynamic load factors, location factors for bending, specific sliding on load-bearing capacity, and surface durability on different tooth sum alterations. The study concludes that tooth sum altered asymmetric gear geometry can be employed as an effective design technique that offers designers flexibility in designing gears for surface wear, load-bearing, and tooth life.

POSSIBILITIES FOR MODIFICATION OF SURGICAL OBTURATOR INTO TEMPORARY OBTURATOR

Background: Maxillary resection causes different types of damages in the maxillofacial area, which are treated by surgical and prosthetic restorative methods. Aim: The described clinical case follows up the initial stages of the prosthetic treatment, as well as the possible modification of surgical obturator into temporary obturator in a patient with maxillary resection. Materials and methods: The prosthetic treatment of a 55-years-old female patient with a surgical operation of upper jaw cancer is described. The surgical obturator is developed a week after the resection. The preliminary impressions are taken with irreversible hydrocolloid impression material. The occlusion height and central relation are fixed by occlusion rims. The surgical obturator was fabricated by heat cured acrylic resin with a low amount of residual monomer. Moreover, metal clasps were used for retention and stability. The borders of the obturating part were covered with a thin layer of relining silicone material after the adjustment. The surgical obturator was modified into a temporary one directly in the patient's mouth after two months by applying the same rebasing material and designing a silicone hollow-bulb obturating part. Results: The treatment results revealed a successful restoration of the patient's speaking, feeding, and swallowing abilities. The application of silicone material inhibited the appearance of decubitus ulcers and facilitated the normal healing process. The direct design of hollow-bulb silicone obturating part significantly improved the retention and stability of the obturator. Conclusion: The application of prosthetic treatment methods in the first days after the maxillary resection allows for restoration of speaking and feeding.

EVALUASI DAN PERBAIKAN DESAIN USER INTERFACE UNTUK MENINGKATKAN USER EXPERIENCE PADA APLIKASI MOBILE SIARAN TANGSEL MENGGUNAKAN METODE GOAL DIRECT DESIGN (GDD)

Mobile Siaran is an official reporting application intended for the people of the city of Tangerang Selatan (South Tangerang). However, after conducting interviews with stakeholders and respondents, there were several problems with the display of the mobile application. From the results of the interview, it indicates that there are still some applications that need improvement. To fix the problem with the Mobile Siaran application display, the solution given is to improve the user interface design using the Goal Direct Design method. In addition, it also uses the success rate calculation technique and the System Usability Scale (SUS) to measure the usability value. Meanwhile, the User Experience Questionnaire (UEQ) measures the value of user experience. The result of this research is a user interface design made in stages in the Goal Direct Design method, namely research, modeling, requirements, frameworks, and refinement. The final evaluation, the results of the improvement using calculations, the success rate has increased from 93.5% to 99.3%, SUS from an average score of 58.19 which can be said to be quite satisfactory with the letter D value to 81.83 which can be accepted with the value of the letter A, while UEQ shows all aspects that have improved with very good and good criteria which means that improvements to user interface design can solve problems that exist in the application and improve the user experience.

Comparative Investigation on Hydrodynamic Performance of Pump-Jet Propulsion Designed by Direct and Inverse Design Methods

Pump-jet propulsion, a new propulsion technology, is primarily designed for underwater vehicles. Because of its concealment and excellent performance, it has been widely used, but due to its confidentiality and complexity, few studies have been published. To explore the relevant design theory of pump-jet propulsion with the aim of increasing its performance, in this study, we applied the direct and inverse design methods to construct a three-dimensional pump-jet model. The direct design method was carried out by comparing the lifting and lifting-line design methods, followed by further geometric optimization of the better model. In a numerical study using computational fluid dynamics (CFD) simulations, the Reynolds Averaged Naviere-Stokes (RANS) equations with SST k-ω turbulence model were solved in a cylindrical computational domain around the pump-jet propulsion device. A numerical investigation of the E779A propeller was carried out beforehand, using different advance ratios, in order to validate the accuracy of the numerical simulation method. The results show that for the direct method, although the model designed using the lifting-line method produced a greater thrust and the pump-jet designed using the lifting method was more efficient and stable, which is more suitable for small and medium underwater vehicles. When considering the inverse design method, the pump-jet propeller obviously accelerated the fluid, and the speed was obviously greater than that designed using the direct design method, while the turbulent kinetic energy in the flow field was higher, as well as the energy loss. Therefore, for small- and medium-sized underwater vehicles, if the priorities are high thrust and high efficiency, the inverse design method is the best option, whereas if stability and lower energy loss are preferred, the direct design method should be adopted.

System-based reliability analysis of stainless steel frames under gravity loads

Current structural codes for steel and stainless steel structures such as AISC 360-16, AISC 370-21, AS/NZS 4100 and Eurocode 3 are based on the traditional two-step member-based design approach, in which internal actions are first obtained from a structural analysis, usually elastic, and the strength of each member and connection is subsequently checked using a structural design standard. However, the most recent versions of these standards already incorporate preliminary versions of the direct, or one-step, system-based design alternative, which is based on the design-by-analysis concept and allows evaluating the strength of structures directly from numerical simulations, although the standards in their current form do not provide reliability requirements for structural systems. Therefore, it is necessary to build a rigorous structural reliability framework to investigate acceptable target reliability indices for structural systems and to provide adequate system safety factors and system resistance factors. While this framework has been developed based on advanced Finite Element analysis for hot-rolled and cold-formed carbon steel structures in recent years in the form of the Direct Design Method (DDM), the framework does not exist for stainless steel structures. This paper presents an extension of the DDM to the analysis of stainless steel structures, in which system reliability calibrations are presented for six stainless steel portal frames under gravity loads covering the three most common stainless steel families and different failure modes using advanced numerical simulations. From the derived reliability calibrations, suitable system safety factors and system resistance factors are proposed for the direct design of stainless steel frames in the European, US and Australian design frameworks under gravity loads.