2,687 research outputs found
Numerical optimization of the suction distribution for laminar flow control aerofoils
No full textIn recent years there has been an increasing interest in the search of methods for drag reduction on aircraft. A promising technique for the reduction of the skin-friction drag is to postpone transition from laminar to turbulent flow using either suction - Laminar Flow Control - or suction plus a favourable pressure gradient - Hybrid Laminar Flow Control. However, for an efficient application of these concepts, the suction distribution has to be optimized to ensure that the gain in drag reduction exceeds the power penalty. In this thesis a numerical algorithm has been developed to optimize the suction distribution over several independent suction panels either while maintaining transition at a desired location or while minimizing the overall power consumption. The numerical code comprises four steps; the calculation of the boundary-layer flow, the determination of the spatial amplification factors of the two-dimensional Tollmien-Schlichting waves, the prediction of the transition location via the eN-method, and finally, the optimization of the suction flow rates. Optimizing the suction distribution while maintaining transition at a desired location can be expressed as a constrained optimization problem, which is solved using an adaptive algorithm based on the gradient projection method. The numerical solution of this problem is very intensive computationally, therefore the use of parallel computation techniques is of advantage. The numerical code has first been applied to flat-plate boundary layers with zero and non-zero pressure gradients and up to eight suction panels, and later to flows over NACA aerofoil sections. Comparison with experimental results has permitted the validation of the code. The results show that suction is a suitable means for the postponement of transition. The optimum suction distribution has been found to be strongly dependent on the pressure distribution, the configuration of the suction panels and the desired transition location.(DX184260)</p
APLIKASI PEMERIKSAAN PERSYARATAN YUDISIUM PADA PROGRAM STUDI TEKNIK INFORMATIKA UNIVERSITAS KRISTEN PETRA
No full textInformatics Engineering Department Petra Christian University do inspection process for judicium manually. This manual process spends considerable time and difficulty in adjusting to the curriculum and regulations. Based on the problems faced by the Department of Informatics, the author develops an application to help speed up and simplify the judicium inspection. This application includes the setting of curriculum, setting fields of study, inspection requirements judicium, determining areas of study graduated students and graduation report. This application was created using ASP.Net programming language and MYSQL as a database. Based on the testing processes, this application has been able to meet the needs of Department of Informatics in the judicium inspection process
Mada'in Salih, a Nabataean town in north west Arabia: analysis and interpretation of the excavation 1986-1990
No full textThis research concerns Mada'in Salih, an archaeological site in north-west Saudi Arabia. Historically, it was part of the Nabataean kingdom which flourished in northwest Arabia (Jordan, parts of Syria, Palestine and some parts of Saudi Arabia), with Petra in Jordan as its capital. The Nabataeans were famous for their trading role, as they transported frankincense and myrrh and exported balsam and bitumen. They built monumental tombs in Petra and Mada'in Salih as well as other public buildings such as temples theatres and baths. They were also famous for their skills in hydraulic engineering and the production of very thin, distinctively painted pottery. Mada'in Salih was an important station on the trade route which linked south Arabia with Mediterranean countries. The main feature of the site is the monumental tombs, which are about eighty in number, some of them dated and bearing inscriptions. Those inscriptions are in Aramaic and usually contain information about the owner name, legal rights, and occasionally the mason's name. Little was known about the site's history and other aspects such as the economy, culture, society and religions prior to the excavation. Various questions were raised which the thesis attempts to address. The archaeological work conducted on the site included a survey, several trenches around the town wall and in front of some of the tombs as well as an excavation in the settlement area. The excavation revealed a private house which furnished us with information regarding house planning, building techniques and materials. A large amount of pottery, small finds and coins were recovered, studied and classified. The results added some information to what was already known about the Nabataeans in general and Mada'in Salih in particular. The site had witnessed its peak during the first century A.D. As most previous archaeological work had been carried out in the northern parts of the Nabataean kingdom, the results of this excavation are important for comparative studies between this, the largest Nabataean settlement centre in the south, to the centres of the north. The trade which had been an important factor in the establishment of the site declined when the trade route was shifted from land to sea by the Romans during the last half of the first century A.D
Professional development portfolio - Petra Trojanová
No full textThe content of the professional development portfolio of Petra Trojanová includes 10 obligatory chapters, dealing with questions about personality and work of a high school teacher. The portfolio brings a look at professional development and self-reflection of writer during her Bachelor's program of Teacher Training in Vocational Education and Training at Faculty of Education, Charles University. One part of the portfolio is devoted to a case study of one selected school focused on teaching vocational training in the field of cosmetic services. The author also maps teacher's individual work activities and their schedule over a month using analysis of professional development of a particular high school teacher. Theoretical knowledge is gathered from the fields of pedagogy, sociology and psychology. KEY WORDS teacher, pupils, burnout syndrome, case study,professional development, individual work activitie
The automatic control of boundary-layer transition: Experiments and computation
No full textIn recent years there has been an increasing interest in the control of boundary-layer transition through the use of wall suction. In the current work suction is provided through one or more suction panels situated close to the leading edge of a plate. Experiments show that boundary-layer pressure fluctuation measurements can be used to identify the position of transition. Transition can be maintained at a desired location with minimum power consumption by employing an automatic adaptive feedback control loop which regulates the suction flow rates of two independent suction panels. This can be expressed as a constrained optimization problem. To allow the suction flow rates to be updated, a modified least mean squares algorithm is used within the control loop. Experimental measurements show that the control algorithm allows fast and stable convergence towards the optimum suction distribution for a double suction panel configuration. Numerical simulations have also been performed. The two-dimensional boundary layer was calculated allowing the viscous boundary layer to interact with the inviscid outer flow. Following linear stability theory the spatial growth rates are calculated by solving an Orr-Sommerfeld type eigenvalue problem, with the streamwise location of transition predicted via the eN -method. Applying the same optimization strategy as in the experiments, good qualitative agreement between computations and experiments was found. The optimization algorithm has been applied to computer models where the relation between suction flow rates and transition location is described by an empirical analytical function. This shows that the controller can in principle be applied to systems with more than two suction panels.</p
German writing author from Bohemia Hanna Demetz (interpretation ot the autobiographical novel "Ein Haus in Böhmen")
No full textTitle: Geman writing Author from Bohemia Hanna Demetz (interpretation of the autobiographical novel "Ein Haus in Böhmen") Department: Department of German language and literature Author: Petra Králíková Supervisor: PhDr. Viera Glosíková, CSc. Pages: 56 Language: German Keywords: The Second World War, Protectorate of Bohemia and Moravia, German written literature, Jews, Germans in Czechoslovakia, anti-Semitism, autobiography, interpretation Abstract: The bachelor thesis comprises the interpretation of the autobiographical novel Ein Haus in Böhmen from a German writing Author from Ústí nad Labem Hanna Demetz. The Analyses were centred on motives of the "coexistence" of the three national groups (Czechs, Jews and Germans) in the days of the Protectorate of Bohemia and Moravia
Factors that affect trust and the access to credit in a bank-firm relationship
No full textAuthor Petra HofbauerAbstract in englischer SpracheMasterarbeit Universität Linz 201
Factors that affect trust and the access to credit in a bank-firm relationship
No full textAuthor Petra HofbauerAbstract in englischer SpracheMasterarbeit Universität Linz 201
Inkjet printing and nanoimprint lithography of biomaterial photopolymers
No full textAuthor Petra Vekszler, BScMasterarbeit Johannes Kepler Universität Linz 2025Arbeit gesperr
Techniques of Respiratory Physiotherapy in Inhalation Therapy of Chronic Pulmonary Disease
No full textOF THE BACHELOR'S THESIS Author: Petra Mandovcová Supervisor: Mgr. Martina Havlová Opponent: Title of bachelor's thesis: Techniques of Respiratory Physiotherapy in inhalation Therapy of Chronic Pulmonary Disease Abstract: This paper is focused on the techniques of respiratory physical therapy in inhalation therapy of chronic pulmonary diseases. The paper is divided into two parts - theoretical and practical. The aim of the theoretical part is to briefly describe anatomy and physiology of respiration. Next, the theoretical part deals with chronic obstructive pulmonary disease and possibilities of its treatment. The emphasis is put on the inhalation therapy and the description of particular techniques of respiratory physical therapy which are used in the therapy of chronic pulmonary diseases. The practical part includes two case histories of patients who are being treated for chronic obstructive pulmonary disease. To evaluate the state of the patient, spirometry testing and the MMRC dyspnea scale are used. The aim of this paper is to show the influence of respiratory physical therapy on efficacy of inhaled medicine concerning the patients with chronic pulmonary diseases. Key words: chronic obstructive pulmonary disease, inhalation therapy, respiratory physical therapy, instrumental technique
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