Fine Grid Numerical Solutions of Triangular Cavity Flow

Numerical solutions of 2-D steady incompressible flow inside a triangular cavity are presented. For the purpose of comparing our results with several different triangular cavity studies with different triangle geometries, a general triangle mapped onto a computational domain is considered. The Navier-Stokes equations in general curvilinear coordinates in streamfunction and vorticity formulation are numerically solved. Using a very fine grid mesh, the triangular cavity flow is solved for high Reynolds numbers. The results are compared with the numerical solutions found in the literature and also with analytical solutions as well. Detailed results are presented

BIOLOGY OF SILKWORM (BOMBYX MORI) IN TURKEY

According to oldest records the first time silkworm was cultivated and silk was obtained from cocoonat China. Silkworm eggs and mulberry seeds was brought to Istanbul illegally the year 552 at age of Byzantine Empire although China kept it as a secret. It started to spread Marmara regione specially Bursa and It’s neighbourhood. Then it was spreaded to allover the world. Sericulture have been economical, cultural and traditional cultivating sector at Turkey for 1500 years. Silkworm is cultivated at about 30 countries that include Turkey. Silk fiber is superior to other fibers in terms of stability, flexibility and brightness. Amount of need is approximately twice the amount of cultivating. In whole world Turkish silk fiber quality is at second rank after japanese silk. Silkworm is a general term that includes a range from worm to the butterfly. Silkworm is a kind of night butterflies. Butterflies are light cream colour have chubby bodies and have soft feathers. Wingspan is about 4-5 cm. Butterfly have lost flying ability because of domestication also have 2 or 3 days life and at that period doesn’t feed and doesn’t fly. Silkworm is fed with mulberry leaves. One cocoon is made from a single silk fiber it’s lenght is 800 meters. Real silkworm named “Bombyx Mori L” is bred at mulberry tree which is cultivated at China is white breed. Bombyx Mori L silkworm producesbest silk fiber amoung other genus and it is most special genus cultivated

A Novel Broadband Multilevel Fast Multipole Algorithm with Incomplete-Leaf Tree Structures for Multiscale Electromagnetic Problems

An efficient and versatile broadband multilevel fast multipole algorithm (MLFMA), which is capable of handling large multiscale electromagnetic problems with a wide dynamic range of mesh sizes, is presented. By invoking a novel concept of incomplete-leaf tree structures, where only the overcrowded boxes are divided into smaller ones for a given population threshold, versatility of using variable-sized boxes is achieved. Consequently, for geometries containing highly overmeshed local regions, the proposed method is always more efficient than the conventional MLFMA for the same accuracy, while it is always more accurate if the efficiency is comparable. Furthermore, in such a population-based clustering scenario, the error is controllable regardless of the number of levels. Several canonical examples are provided to demonstrate the superior efficiency and accuracy of the proposed algorithm in comparison with the conventional MLFMA. � 2016 IEEE

Broadband multilevel fast multipole algorithm for large-scale problems with nonuniform discretizations

We present a broadband implementation of the multilevel fast multipole algorithm (MLFMA) for fast and accurate solutions of multiscale problems involving highly nonuniform discretizations. Incomplete tree structures, which are based on population-based clustering with flexible leaf-level boxes at different levels, are used to handle extremely varying triangulation sizes on the same structures. Superior efficiency and accuracy of the developed implementation, in comparison to the standard and broadband MLFMA solvers employing conventional tree structures, are demonstrated on practical problems. © 2016 IEEE

Efficient analysis of phased arrays of microstrip patches using a hybrid generalized forward backward method/green's function technique with a DFT based acceleration algorithm

A hybrid method based on the combination of generalized forward backward method (GFBM) and Green's function for the grounded dielectric slab together with the acceleration of the combination via a discrete Fourier transform (DFT) based algorithm is developed for the efficient and accurate analysis of electromagnetic radiation/scattering from electrically large, irregularly contoured two-dimensional arrays consisting of finite number of probe-fed microstrip patches. In this method, unknown current coefficients corresponding to a single patch are first solved by a conventional Galerkin type hybrid method of moments (MoM)/Green's function technique that uses the grounded dielectric slab's Green's function. Because the current distribution on the microstrip patch can be expanded using an arbitrary number of subsectional basis functions, the patch can have any shape. The solution for the array currents is then found through GFBM, where it sweeps the current computation element by element. The computational complexity of this method, which is originally O(Ntot 2 being the total number of unknowns) for each iteration, is reduced to O(Ntot) using a DFT based acceleration algorithm making use of the fact that array elements are identical and the array is periodic. Numerical results in the form of array current distribution are given for various sized arrays of probe-fed microstrip patches with elliptical and/or circular boundaries, and are compared with the conventional MoM results to illustrate the efficiency and accuracy of the method. © 2008 IEEE

Finite volume simulation of 2-D steady square lid driven cavity flow at high reynolds numbers

In this work, computer simulation results of steady incompressible flow in a 2-D square lid-driven cavity up to Reynolds number (Re) 65000 are presented and compared with those of earlier studies. The governing flow equations are solved by using the finite volume approach. Quadratic upstream interpolation for convective kinematics (QUICK) is used for the approximation of the convective terms in the flow equations. In the implementation of QUICK, the deferred correction technique is adopted. A non-uniform staggered grid arrangement of 768x768 is employed to discretize the flow geometry. Algebraic forms of the coupled flow equations are then solved through the iterative SIMPLE (Semi-Implicit Method for Pressure-Linked Equation) algorithm. The outlined computational methodology allows one to meet the main objective of this work, which is to address the computational convergence and wiggled flow problems encountered at high Reynolds and Peclet (Pe) numbers. Furthermore, after Re > 25000 additional vortexes appear at the bottom left and right corners that have not been observed in earlier studies

An electromagnetic sensing system incorporating multiple probes and single antenna for wireless structural health monitoring

In this study, a wireless and passive displacement/strain sensing system is proposed for structural health monitoring (SHM). The wireless and passive interrogation of the sensing unit [a variant of a nested split-ring resonator (NSRR)] is achieved through the near-field interaction and electromagnetic coupling between the single antenna in the system and the multiple sensors called the NSRR probes. It is demonstrated that the system can acquire data from more than one NSRR probe simultaneously in a real-life scenario, where the probes are confined within concrete inside a beam, while the antenna monitors them from outside. © 2017 Euraap

A wireless passive sensing system for displacement/strain measurement in reinforced concrete members

In this study, we show a wireless passive sensing system embedded in a reinforced concrete member successfully being employed for the measurement of relative displacement and strain in a simply supported beam experiment. The system utilizes electromagnetic coupling between the transceiver antenna located outside the beam, and the sensing probes placed on the reinforcing bar (rebar) surface inside the beam. The probes were designed in the form of a nested split-ring resonator, a metamaterial-based structure chosen for its compact size and high sensitivity/resolution, which is at µm/microstrains level. Experiments were performed in both the elastic and plastic deformation cases of steel rebars, and the sensing system was demonstrated to acquire telemetric data in both cases. The wireless measurement results from multiple probes are compared with the data obtained from the strain gages, and an excellent agreement is observed. A discrete time measurement where the system records data at different force levels is also shown. Practical issues regarding the placement of the sensors and accurate recording of data are discussed. The proposed sensing technology is demonstrated to be a good candidate for wireless structural health monitoring (SHM) of reinforced concrete members by its high sensitivity and wide dynamic range. © 2016 by the authors; licensee MDPI, Basel, Switzerland

Multi-Point Single-Antenna Sensing Enabled by Wireless Nested Split-Ring Resonator Sensors

In this paper, simultaneous multi-point wireless sensing is proposed and demonstrated via multiple sensors in nested split-ring resonator (NSRR) geometry coupled to a single illuminator antenna. In this passive multi-point sensing system, each probe in the sensor array is assigned a non-overlapping spectral interval for frequency shift in response to local mechanical loading around a unique operating resonance frequency in the band of the antenna. Here, it is shown that the antenna is capable of capturing the responses from all probes in a single frequency sweep. Furthermore, the inter-coupling between the array elements and the effect of antenna illumination on the coupling are experimentally investigated in a systematic way. In addition, as a proof-of-concept real-life application in structural health monitoring, two NSRR sensors are located inside a concrete beam to monitor the strain forming on reinforcing bars, and this dual-probe system is demonstrated to record strain simultaneously via both of the embedded probes. © 2001-2012 IEEE