Effect of paragliding wing dome shape on its aerodynamic characteristics

Double-membrane gliding parachutes (DGP) obtain their wide variety of application, including the solution of cargo transportation problems. This parachute is a flexible canopy, which shape is maintained by ram air. In terms of the aerodynamic performance calculation and analysis when operating, DGP is the most complex aero elastic system. The computation of DPG aerodynamic performance is only possible, utilizing the methods of nonlinear aerodynamics and the nonlinear theory of elasticity methods.This paper investigates the aerodynamic characteristics of stable geometric shapes for various gliding parachutes, taking into account their dome shape both chord-wise and span-wise. Notably, the volumetric parachute profile is modeled by its median surface. The research, conducted by the authors, showed that such an aero elastic model of DGP allows you to obtain results that reflect correctly the qualitative effects of detached and free streamline flow. To solve the problem about the airflow over a gliding parachute, considering its canopy curvature, the method of discrete vortices with closed frames is employed, which allows you to calculate the paragliding wing aerodynamic performance within a wide range of angles of attack. There is also a possibility of flow separation simulation. The ideal incompressible liquid flow over the median surface of a stable shape for a double-membrane gliding parachute is regarded. The parachute fabric porosity is not analyzed, since the upper and lower DGP panels are made of either the low permeable or non-porous fabric. In the separated flow past, the aerodynamic coefficients are identified by time averaging to its large values after computing. The DGP aerodynamic performance computation results are given at a different value of its dome shape, as in the free streamline flow as in the flow separation. The computed coefficients, that allow us to consider the influence of canopy dome shape on its aerodynamic characteristics, are obtained. The proposed technique can be used for operational estimates of aerodynamic forces while designing and planning a pipe experiment.

Spatial Distribution of Grain Size Within Nitraria retusa Coppice Dune in Kuwait

Nabkhas are desert and sabkha perennial plants that form stabilized dunes. A total of 23 sediment samples were taken from the surface and subsurface (30 cm depth) of nabkha that formed around Nitraria retusa as the dominant perennial plant species in Ghudai-Kuwait. The morphological and ecological functions of sabkha nabkha are distinguishable. The existence of shallow fresh groundwater that floats atop the saline water bodies and is recharged by rainwater and surface drainage routes is due to the presence of thriving nabkhas within a salty sabkha environment. the selected non-protected Nitraria nebkhas have an elongated dome shape with a height of 1.30 m and an average length of 11.80 m. also, the greatest distances between isolated nabkhas are found in Nitraria dominated coppice dunes. There are three types of Nitraria dominated coppice dunes, namely: single (one plant), coupled (two plants), and complex (three or more). Nitraria is considered one of Kuwait’s most effective plant species for trapping mobile sand, Nitraria can to tarp to 21 m3 of mobile sand and dust. The variations in grain size sediments in Nitraria retusa between surface and root zone, border and crest, upwind and downwind, are efficient for retaining water. Furthermore, Nitraria retusa from the sabkha environment is the most effective in collecting mobile sand in the region.

New Importance Measures Based on Failure Probability in Global Sensitivity Analysis of Reliability

This article presents new sensitivity measures in reliability-oriented global sensitivity analysis. The obtained results show that the contrast and the newly proposed sensitivity measures (entropy and two others) effectively describe the influence of input random variables on the probability of failure Pf. The contrast sensitivity measure builds on Sobol, using the variance of the binary outcome as either a success (0) or a failure (1). In Bernoulli distribution, variance Pf(1 − Pf) and discrete entropy—Pfln(Pf) − (1 − Pf)ln(1 − Pf) are similar to dome functions. By replacing the variance with discrete entropy, a new alternative sensitivity measure is obtained, and then two additional new alternative measures are derived. It is shown that the desired property of all the measures is a dome shape; the rise is not important. Although the decomposition of sensitivity indices with alternative measures is not proven, the case studies suggest a rationale structure of all the indices in the sensitivity analysis of small Pf. The sensitivity ranking of input variables based on the total indices is approximately the same, but the proportions of the first-order and the higher-order indices are very different. Discrete entropy gives significantly higher proportions of first-order sensitivity indices than the other sensitivity measures, presenting entropy as an interesting new sensitivity measure of engineering reliability.

A MONTE CARLO SIMULATION STUDY ON THE DOME EFFECT

A dome-shape deformation has been found to affect the photogrammetric surface reconstruction in several real and simulated experiments. Its origin has been recognised in inaccurate estimation of the camera parameters and many papers already concentrated on conditions to avoid its development, especially as far as block design is concerned. This paper presents a Monte Carlo simulation to investigate surface reconstruction elevation errors in UAV (Unmanned Aerial Vehicle) photogrammetric blocks. The simulation tests are designed to find out the effect of block shape, camera axis inclination, side-lap, cross strips addition and block control by GCP or GNSS-assisted on the extent of the deformations. The main findings are: i) that GNSS-assisted blocks are generally more robust compared to GCP-controlled ones; ii) that, in GNSS-assisted blocks, unless a mix of nadiral and inclined strips is present, at least one fixed GCP must be provided; iii) that cross strip can conveniently be slimmed to save flight time and processing time; iv) that the effectiveness of GNSS deteriorate as the block shape slims out.

ANALISIS BENTUK KUBAH DAN AKULTURASI BUDAYA PADA BANGUNAN MASJID AL OSMANI MEDAN

<div class="WordSection1"><p><strong><em>Abstract</em></strong></p><p><em>Medan City is a combination of several ethnicities and cultures, because in Medan there are several Acehnese, Batak and Malay ethnic groups. Medan has a Malay Deli building with exotic religious and artistic nuances to visit, especially if we like typical Malay buildings such as the Al Osmani Mosque building which still elevates and preserves cultural arts even though there has been a renewal of traditional architecture into modern architecture, but the Malay building still has value. aesthetics with various types of ornament forms, colors, placement of Malay ornaments and also the acculturation of various cultures. Al Osmani Mosque was first built in 1854 with selected wood materials imported from Penang. During the VII Deli Malay Sultanate, namely Sultan Osman Perkasa Alam. Then in 1870 - 1872 the wooden mosque was built permanently by his son, Sultan Mahmud Perkasa Alam (VIII Sultan of Deli). The Al Osmani mosque building was designed by a German architect named GD Langereis with materials sent from Spain and Persia. This study uses a historical approach and aesthetic approach. The historical approach will involve a discussion of the origins of the building form of the Al Osmani Mosque and its functional development since it was founded until now. The aesthetic approach will involve a discussion of the dome shape of the Al Osmani Mosque, what cultural acculturations are there in the Medan Al Osmani Mosque building so that it can attract attention and have unique characteristics? The results showed that the Al Osmani Mosque and its interior as well as the space filling elements in it were not fully influenced by the aesthetics of the forms that came from the Deli Malay culture but were also influenced by the aesthetic forms of Chinese, European, Indian and Middle Eastern cultures.</em><em></em></p><p><strong><em>Keywords : </em></strong><em>Acculturation, Ornaments, Aesthetics, History, Al Osmani Mosque.</em></p><p><strong><em> </em></strong></p><p><strong> </strong></p><p><strong>Abstrak</strong></p><p>Kota Medan merupakan perpaduan dari beberapa etnis dan budaya, karena di Kota Medan di dapati beberapa etnis Aceh, etnis Batak dan etnis Melayu. Medan memiliki bangunan Melayu Deli bernuansa seni dan religi yang eksotis untuk dikunjungi khususnya jika kita menyukai bangunan-bangunan khas Melayu seperti Bangunan Masjid Al Osmani masih mengangkat dan melestarikan seni budaya meskipun terjadi pembaharuan arsitektur tradisional menjadi arsitektur modern, tetapi pada bangunan Melayu tersebut masih memiliki nilai estetis dengan berbagai jenis bentuk ornamen, warna, penempatan ornamen Melayu dan juga akulturasi dari berbagai budaya. Masjid Al Osmani pertama kali dibangun pada tahun 1854 dengan bahan kayu pilihan yang didatangkan dari Penang. Pada masa Kesultanan Melayu Deli ke-VII yaitu Sultan Osman Perkasa Alam. Kemudian pada tahun 1870 - 1872 masjid yang terbuat dari bahan kayu itu dibangun permanen oleh putranya yakni Sultan Mahmud Perkasa Alam (Sultan Deli ke-VIII). Bangunan masjid Al Osmani di desain oleh arsitek asal Jerman yang bernama GD Langereis dengan material yang dikirim dari Spanyol dan Persia. Penelitian ini menggunakan pendekatan sejarah dan pendekatan estetika. Pendekatan sejarah akan menyangkut pembahasan tentang asal-usul bentuk bangunan Masjid Al Osmani dan perkembangan fungsionalnya sejak didirikan hingga sekarang. Pendekatan estetika akan menyangkut pembahasan tentang bentuk kubah Masjid Al Osmani, akulturasi budaya apa saja yang terdapat pada bangunan Masjid Al Osmani Medan sehingga bisa menarik perhatian dan memiliki ciri khas yang unik?. Hasil penelitian memperlihatkan bahwa Masjid Al Osmani dan interiornya serta elemen pengisi ruang di dalamnya tidak sepenuhnya dipengaruhi oleh estetika bentuk yang berasal dari budaya Melayu Deli tetapi juga dipengaruhi oleh estetika bentuk dari kebudayaan China, Eropa, India dan Timur Tengah.</p></div><p><strong>Kata Kunci :</strong> Akulturasi, Ornamen, Estetika, Sejarah, Masjid Al Osmani.</p>

Innovative Designs in Household Biogas Digester in Built Neighbourhoods

Most household biogas digesters operate on continuous automatic stirring modes. Often, these digesters rely on electrical energy for their continuous operations which are often mesophilic. Rarely do manually-stirred discontinuous household biogas digesters operating on hyper-thermophilic conditions exist. This work seeks to highlight some innovative designs in a household biogas digester piloted in Terterkessim slum in the K.E.E.A. Municipality of the Central Region, Ghana. A pyramidal dome-shape biogas digester was constructed on an abandoned septic tank using blocks and concrete. The digester has a rectangular sub-surface base and a pyramidal gas holder above the surface of the soil. The digester has a two-blade manual stirrer, a ball bearing affixed at the bottom and a handle to manually mix the content of the digester. In order to heat the content of the digester to a hyper-thermophilic condition for hygienising the digestate, a solar-photovoltaic was installed on the roof of a toilet connected to the household biogas digester.

Structural phase transition and superconductivity hierarchy in 1T-TaS2 under pressure up to 100 GPa

The adoption of high pressure not only reinforces the comprehension of the structure and exotic electronic states of transition metal dichalcogenides (TMDs) but also promotes the discovery of intriguing phenomena. Here, 1T-TaS2 was investigated up to 100 GPa, and re-enhanced superconductivity was found with structural phase transitions. The discovered I4/mmm TaS2 presents strong electron–phonon coupling, revealing a good superconductivity of the nonlayered structure. The P–T phase diagram shows a dome shape centered at ~20 GPa, which is attributed to the distortion of the 1T structure. Accompanied by the transition to nonlayered structure above 44.5 GPa, the superconducting critical temperature shows an increasing trend and reaches ~7 K at the highest studied pressure, presenting superior superconductivity compared to the original layered structure. It is unexpected that the pressure-induced re-enhanced superconductivity was observed in TMDs, and the transition from a superconductor with complicated electron-pairing mechanism to a phonon-mediated superconductor would expand the field of pressure-modified superconductivity.