Wing-tip vanes as vortex attenuation and induced drag reduction devices

Analytical studies have been conducted to examine the feasibility of utilizing wing tip turbines to remove swirl from the wing trailing vortex, and hence reduce the potential for upset of following aircraft. Energy recovery from the turbines is also analyzed. A computer routine has been developed to permit rapid parametric studies of various tip turbine designs. It is shown that the optimum turbine is a non-rotating set of vanes which reduce swirl and recover energy in the form of reduced overall configuration induced drag. A specific case study indicates a 23% reduction in induced drag for a rectangular wing of aspect ratio 5.33, operated at a lift coefficient at 1.0

Repair of Steel Bridge Girders Damaged by Distortion-Induced Fatigue

Several studies have identified distortion-induced fatigue as the leading cause of cracks in steel bridges built prior to the mid-1980s. Experimental and computer simulations of 914-mm (36-in.) deep girder-cross frame subassemblies subjected to cyclic loading were carried out to study the effects of distortion-induced fatigue and to evaluate the effectiveness of various retrofit measures. Previous repair methods for distortion-induced fatigue damage have attempted to reduce the stress demand at the critical web-gap region by increasing the flexibility of the girder web in the out-of-plane direction or by restraining the lateral motion of the web by fixing the connection stiffener to the girder flange. A new approach was investigated in this study intended to reduce the stress demand in the web-gap region by re-distributing the out-of-plane force transferred through the girder-cross frame connection over a larger area of the girder web. A new retrofit measure is proposed based on this approach, which consists of adding steel angles connecting the girder web and the connection plate (CP), and a steel plate on the back side of the girder web to distribute the lateral force over a wider region of the web. Experimental and computer simulation results are presented showing that this repair method is very effective in preventing the growth of horseshoe-shaped cracks around the web cross-frame connection and of horizontal cracks near the junction between the flange and web

Design and Analysis of Fractal Monopole Antennas for Multiband Wireless Applications

In this report three antenna designs using fractal geometry have been proposed. Fractal is a concept which is being employed in patch antenna to have better characteristics than conventional microstrip antenna. In the first design, a Sierpinski fractal antenna is proposed for multiband wireless applications. It consists of three-stage Sierpinski fractal geometry as the radiating element. The proposed antenna has compact dimension of 75×89.5×1.5 mm3. The multiband characteristic for a return loss less than 10dB is achieved. The model is applied to predict the behavior of fractal antenna when the height of the antenna is changed. The proposed antenna is considered a good candidate for Multiband Wireless applications. In the second proposal, a Sierpinski Carpet fractal antenna is proposed for multiband wireless applications. It consists of two-stage Sierpinski Carpet fractal geometry as the radiating element. The proposed antenna has compact dimension of 59.06×47.16×1.6 mm3. The multiband characteristic for a return loss less than 10dB is achieved. The major advantage of Sierpinski Carpet antenna is, it exhibits high self-similarity and symmetry. In the third proposal, multiband Koch curve antenna with fractal concept is presented. It consists of two-stage Koch curve as the radiating element. The proposed antenna is a compact dimension of 88×88×1.6 mm3. The multiband characteristic for a return loss less than 10dB is achieved. The proposed design is appropriate for mobile communication systems. CST Microwave Studio Suite 2012 is used to simulate these antennas. All the proposed antennas are fabricated on FR4 substrate of relative permittivity of 4.4 and height 1.6mm has been used

Vortex sheet modeling with higher order curved panels

A method to predict the shape of the vortex sheet in the vicinity of its generating lifting surface is presented. The method uses potential flow vortex panels with a bilinear vorticity distribution and bicubic position interpolant to enable continuity to the necessary order. Positions of the panel nodes of successive streamwise stations are iteratively updated using the induced velocities computed from the sheet\u27s configuration during the previous cycle;Complex wing loadings can be used, such as the case of deployed partial span flaps, or stalled conditions. However, the spanwise node density must be adjusted accordingly;Good correlation was obtained for a simply loaded wing tested in the Boeing Company Research Wind Tunnel, and the results show a considerable improvement over current methods of prediction which use discrete vortex filaments;Such a method would be useful in predicting certain stability derivatives in various flight regimes, as well as in the evaluation of the induced effects on other aircraft surfaces

Vortex sheet modeling with higher order curved panels

A numerical technique is presented for modeling the vortex sheet with a deformable surface definition, along which a continuous vortex strength distribution in the spanwise direction is applied, so that by repeatedly modifying its shape, its true configuration is approached, in the proximity of its generating wing. Design problems requiring the inclusion of a realistic configuration of the vortex sheet are numerous. Examples discussed include: control effectiveness and stability derivatives, longitudinal stability, lateral stability, canards, propellers and helicopter rotors, and trailing vortex hazards

The Role Of Reputation In Market Entry: Evidence From French Public Procurement

This article studies the impact of reputation on market entry in public procurement. Based on the observation of a French firm with a strong reputation, we demonstrate a significant effect of the difference in public contracts won between date t-1 and date t. Our model provides empirical proof that selection of a supplier with a strong reputation does not hinder entry in public procurement nor does it prevent free competition. This result thus questions the justification for the European Union regulation that limits the use of information on past performance to select suppliers in public markets. The findings also suggest that reputation mechanisms can help reduce uncertainty during contract execution.

INDIGENOUS PEOPLE: EMANCIPATORY POSSIBILITIES IN CURRICULUM DEVELOPMENT

In this article, I argue that emancipatory possibilities for Mäori, the Indigenous people of New Zealand, rely on structural changes that enable them to have control over resources, decision making, and meaning, and that emancipation is a journey traveled by oppressed groups as they exercise their collective agency. The 1990s development of Pängarau, the national mathematics curriculum policy in the medium of Mäori, provides the context for this discussion. Recent developments indicate that state structures have shifted towards giving Mäori more control in curriculum writing. Key words: collective agency, state structures, Indigenous curriculum development, New Zealand education, Mäori education, mathematics education Dans cet article, l’auteure soutient que les possibilités d’émancipation des Maori, le peuple autochtone de la Nouvelle‐Zélande, reposent sur des changements structu‐ raux qui leur permettent d’avoir la haute main sur des ressources, la prise de déci‐ sions et l’orientation générale et que l’émancipation est un chemin parcouru par des groupes opprimés qui exercent une action collective. L’élaboration dans les années 1990 de Pängarau, la politique nationale relative à l’enseignement des mathématiques en maori, fournit le contexte de l’analyse présentée ici. Des faits récents indiquent que les structures de l’État évoluent vers la remise d’un contrôle accru aux Maori pour ce qui est de l’élaboration des programmes d’études. Mots clés : action collective, structures étatiques, élaboration de programmes d’études par des autochtones, éducation en Nouvelle‐Zélande, éducation dispensée aux Maori, enseignement des mathématiques

PELATIHAN KONDISI FISIK PELATIH CABANG OLAHRAGA KOTA TANGERANG DALAM RANGKA PERSIAPAN PORPROV BANTEN 2022

Permasalahan latihan Fisik dan penyusunan program latihan fisik terkadang diabaikan baik itu dalam program dan pembinaan atlet yang berprestasi baik ditingkat Provinsi, Nasional maupun Internasional. Penelitian ini bertujuan untuk mengetahui Pelatihan kondisi fisik pada para pelatih cabang olahraga kota Tangerang dalam rangka Persiapan Porprov Banten 2022. Penelitian ini menggunakan metode survei. Sampel dalam penelitian ini adalah para Pelatih cabang olahraga Kota Tagerang. Teknik analisis data yang digunakan dalam penelitian ini adalah menggunakan analisis deskriptif. Penelitian tentang  Pelatihan kondisi fisik pada para Pelatih cabang olahraga Kota Tangerang Dalam Rangka Persiapan  Porprov Banten 2022 agar para pelatih memahami tentang pentingnya latihan fisik, membuat program latihan Fisik. Semua yang terlibat dalam pelatihan ini harus mendapatkan pembekalan yang mendalam agar dapat menyusun dan membuat program latihan dengan tepat sesuai sasaran atau tujuan di Porprov 2022 dan mencapai prestasi yang optimal dan dimana sekaligus Kota Tangerang menjadi Juara Umum Pada Porprov Banten 202

Constraints on the evolution of Taranaki Fault from thermochronology and basin analysis: Implications for the Taranaki Fault play

Taranaki Fault is the major structure defining the eastern margin of Taranaki Basin and marks the juxtaposition of basement with the Late Cretaceous-Paleogene succession in the basin. Although the timing of the basement over-thrusting on Taranaki Fault and subsequent marine onlap on to the basement block are well constrained as having occurred during the Early Miocene, the age of formation of this major structure, its character, displacement history and associated regional vertical movement during the Late Cretaceous- Recent are otherwise poorly known. Here we have applied (i) apatite fission track thermochronology to Mesozoic basement encountered in exploration holes and in outcrop to constrain the amount and timing of Late Cretaceous-Eocene exhumation of the eastern side of the fault, (ii) basin analysis of the Oligocene and Miocene succession east of the fault to establish the late-Early Miocene - Early Pliocene subsidence history, and (iii), regional porosity-bulk density trends in Neogene mudstone to establish the late uplift and tilting of eastern Taranaki Basin margin, which may have been associated with the main period of charge of the underlying Taranaki Fault play. We make the following conclusions that may be useful in assessing the viability of the Taranaki Fault play. (1) Mid-Cretaceous Taniwha Formation, intersected in Te Ranga-1 was formerly extensive across the western half of the Kawhia Syncline between Port Waikato and Awakino. (2) Taranaki Fault first formed as a normalfault during the Late Cretaceous around 85±10 Ma, and formed the eastern boundary of the Taranaki Rift-Transform basin. (3) Manganui Fault, located onshore north of Awakino, formed as a steeply east dipping reverse fault and accommodated about four km of displacement during the mid-Cretaceous. (4) Uplift and erosion, involving inversion of Early Oligocene deposits, occurred along the Herangi High during the Late Oligocene. This may have been associated with initial reverse movement on Taranaki Fault. (5) During the Early Miocene (Otaian Stage) the Taranaki and Manganui Faults accommodated the westward transport of Murihiku basement into the eastern margin of Taranaki Basin, but the amount of topography generated over the Herangi High can only have been a few hundred metres in elevation. (6) The Altonian (19-16 Ma) marked the start of the collapse of the eastern margin of Taranaki Basin that lead during the Middle Miocene to the eastward retrogradation of the continental margin wedge into the King Country region. During the Late Miocene, from about 11 Ma, a thick shelf-slope continental margin wedge prograded northward into the King Country region and infilled it (Mt Messenger, Urenui, Kiore and Matemateaonga Formations). (7) During the Pliocene and Pleistocene the whole of central New Zealand, including the eastern margin of Taranaki Basin, became involved in long wavelength up-doming with 1-2 km erosion of much of the Neogene succession in the King Country region. This regionally elevated the Taranaki Fault play into which hydrocarbons may have migrated from the Northern Graben region

When Revolution Meets Design Studio: Initiating academic debate on “a new urban order”

In the context of the January 2011 Revolution, architects and planners in Egypt were inspired by the revolutionary process. They envisioned new modes of pedagogy and professional practice. This paper exposes an initiative led by the Architectural Department at Cairo University to develop the 2011 graduation project as a contribution to the ongoing restructuring of the city and public space into citizen-initiated and inclusive settings for emerging social and political orders. This paper documents the work of 16 students, each with his or her particular site and project, within the broader framework of the “Building Legitimacy” mashru‘ (project). It critically discusses the limitations and challenges encountered during the process and reflects on the capacity of the Studio to contribute to the wider urban debate in Egypt.Après le 25 janvier 2011, architectes et urbanistes se sont inspirés du processus révolutionnaire pour imaginer de nouvelles pédagogies et de nouvelles pratiques professionnelles. Cet article décrit une initiative pilotée par le département d’architecture de l’Université du Caire, dont les projets de fin d’étude visent à contribuer à la restructuration du Caire et de ses espaces publics. La promotion 2011 a cherché à faire de ces contributions des projets laissant l’initiative aux citoyens, en accord avec un ordre social et politique émergeant. L’article rend compte du travail de 16 étudiant-e-s, chacun-e avec sur un site ou un projet particulier, dans le cadre plus général d’un projet baptisé « Building Legitimacy ». Il aborde de manière critique les limites et défis rencontrés au cours de la démarche et s’interroge sur la capacité de l’atelier à contribuer à un débat urbain plus large en Egypte