Position Of Notches Research Articles

Design criteria for the folding implosion of high-rise RC buildings

Blasting is an efficient method for demolishing high-rise buildings and structures. If the collapse scope of a building to be blasted is insufficient controlled building implosion technology is preferred. However, for the conventional implosion, there is a lot of pre-weakening work that has to be done, and it is almost impossible to demolish the high-rise thin wall structures such as reinforced concrete (RC) chimneys. Therefore, a folding implosion method is proposed. In this method, several wedge-shaped notches should be blasted out in the high-rise building or structure, then these notches will turn to “plastic hinges”, meanwhile, the building or structure will turn to a folding kinematic chain, and the segments will overlap each other after falling down. For this method, some design criteria for the main parameters such as the position, initiation sequence, and initiation time delay of blast notches are proposed. The multi-body dynamics models for bi-folding implosion and tri-folding implosion are deduced to analyze the folding motions and rationality of the blasting plans. In two implosion cases, the design criteria and kinematics models are validated.

Minimized reflectionless bandpass filter with four notches and low insertion loss

ABSTRACTA size-minimized low-insertion-loss reflectionless bandpass filter with four notches is presented in this paper. The insertion loss of two quasi-elliptic-type filters is studied and optimized by a new approach based on cascade resonators branches. Parameters extraction procedure for the desired position of notches is illustrated. The inband performance, bandwidth and notch width are studied. This novel approach brings lower insertion loss. It can be extended to reflectionless bandpass filters with arbitrary number of notches. The size of filter is also minimized. This filter is designed, simulated, fabricated and measured. It is centered at 3.481 GHz with a 3-dB bandwidth of 276 MHz. The minimum measured in-band insertion loss, including the loss of SMA interface, is 1.239 dB. Four notches are located at 2.827, 3.238, 3.825 and 4.306 GHz, respectively. S11 of this filter is less than −10 dB during 2–5 GHz.

Damage detection in CFRP composite beams based on vibration analysis using proper orthogonal decomposition method with radial basis functions and cuckoo search algorithm

This paper presents a new fast approach for crack identification using vibration analysis based on model reduction using proper orthogonal decomposition method with radial basis function (POD-RBF). The method is formulated as an inverse problem for detecting the position, length and depth of crack in Carbon Fibre Reinforced Polymer (CFRP) composite structures, where Genetic and Cuckoo search algorithms are used to minimize the cost function based on numerical and experimental natural frequencies. The results show that the POD-RBF combined with Cuckoo search algorithm is an efficient and a feasible methodology of predicting the width, depth and position of double rectangular notches in CFRP beams. The stability of this technique is tested by introducing a white Gaussian noise in the frequencies data input. The results show that the proposed approach is stable when the noise level is lower than 6%.

Abrasive notches along the Atlantic Patagonian coast and their potential use as sea level markers: the case of Puerto Deseado (Santa Cruz, Argentina)

ABSTRACTPatagonia Argentina is a key area for the study of sea level changes in the southern hemisphere, but the availability of reliable sea level markers in this area is still problematic. In fact the storm deposits (beach ridge) commonly used here to reconstruct past sea level oscillations introduce a wide error. Along the Puerto Deseado coast (Santa Cruz), morphometric analyses of 11 features were carried out using traditional measurement tools and a digital software‐based method (tested on one selected feature) with the aim to investigate the possibility of their use as sea level markers. By undertaking accurate topographic profiles we identified the relationship between notches and current sea level. In detail, we identified two clusters of notch retreat point elevations, with a very low internal variability. The lower was located a little below the mean high tide level (mHT) and the upper located at least 0.5 m above the maximum high tide level (MHT). Field observations of tidal levels and the position of notches suggest that the lower notches are active and the upper are inactive. This study on the abrasive notches attests their quality as sea level markers and opens up the use of fossil abrasive notches as palaeo sea level markers because the error linked to these features is substantially smaller than that introduced by beach ridges commonly used in the study area. Copyright © 2014 John Wiley & Sons, Ltd.

Research on Power Line as Communication Channel with Multi-Tap and Multi-Branch Configuration

To study the effect of different branch configuration on transmission characteristic in-home low-voltage (LV) communication power line communication (PLC) channel, the influences of branch length, number of branch and tap, and branch terminal impedance on the performance of PLC are investigated. The two type power line network structures of the one-tap with multi-branch (OTMB) and the multi-tap with multi-branch (MTMB) are studied. The transmission characteristics of the PLC channel are simulated by varying the length and terminal impedance of the branch for two configurations. Simulation results show that the length and terminal impedance of the branch have significant influence on the amplitude and phase response of the transfer function. The position and number of notches and crests in the amplitude responses are affected by different branch types and the configurations of branch length and branch terminal impedance. The models developed in this paper can easily handle an arbitrary topology of power line channel and provide accurate calculation for the channel responses of the all kinds of channel branch structures in indoor LV power line network

단상 BLDC 전동기의 코깅토크 저감을 위한 고정자 형상 최적설계

This paper proposes the optimal design of stator shape for cogging torque reduction of single-phase brushless DC (BLDC) motor with asymmetric notch. This method applied size and position of asymmetric notches to tapered teeth of stator for single-phase BLDC motor. Which affects the variation of the residual flux density of the permanent magnet. The process of optimal design included the extraction of the sampling point by using Latin Hypercube Sampling(LHS), and involved the creation of an approximation model by using kriging method. Also, the optimum point of the design variables were discovered by using the Genetic Algorithm(GA). Finite element analysis was used to calculate the characteristics analysis and cogging torque. As a result of finite element analysis, cogging torque were reduced approximately 39.2% lower than initial model. Also experimental result were approximately 38.5% lower than initial model. The period and magnitude of the cogging torque were similar to the results of FEA.

Modeling Transfer Function of Electrical Power Lines for Broadband Power Line Communication

The indoor access network is characterized by several branches that cause many reflections. In this paper, we present an approach to model the transfer function of electrical power lines for broadband power line communication. The assuming channel consists of three wires, which is widely used in many countries. As an application of the proposed method, the effect of line length from transmitter to receiver, branched line length and number of branched are also studied. From the frequency response of the transfer function (magnitude and phase), it is seen that the position of notches and peaks in the magnitude responses are largely affected in terms of attenuation by the electrical network which consists of 15 branches.

Optical Quality-Assessment of High-Order One-Dimensional Silicon Photonic Crystals With a Reflectivity Notch at $\lambda \sim 1.55\ \mu\hbox{m}$

In this paper, high-order silicon/air vertical 1-D photonic crystals (PhCs) featuring a deep reflectivity notch (Q of about 3000) within the third telecommunication transmission window are fabricated by electrochemical micromachining of silicon and optically characterized. Although, from scanning electron microscope (SEM) investigations, the microfabricated structures appear to be of high quality in terms of in-plane and out-of-plane uniformity as well as of low surface roughness, optical measurements highlight variability of the spectral position of reflectivity notches, which turns out to be affected by fine variations of structural features induced by fabrication. A nondestructive optical method is used to recover the distribution of typical fabrication features, which is not easily quantifiable with other techniques in these high aspect-ratio vertical structures, from the experimentally detected distribution of the optical features. Optical distribution is obtained by scanning the device with high spatial resolution and recording spectral reflectivity at normal incidence (in the wavelength range 1.0-1.7 μm) on different locations of the 1-D PhC surface (X-Y plane). Distribution of silicon thickness variation on the X-Y plane is then inferred by best fitting the experimental spectral reflectivity data with theoretical spectra that are calculated by taking into account nonidealities of both PhC structure and measuring setup. On-sample fabrication-induced variation of the average silicon thickness, as a function of the X-Y position, is estimated to be limited to ±80 nm (percentage error of ±1%) within a range of ±100 μm from a reference location. As a consequence of such thickness variation, a maximum shift of the reflectivity spectrum of 40 nm occurs as a function of the X-Y position in the range of ±100 μm. Sample-to-sample average silicon thickness variation among nominally equivalent structures is also tested in similar X-Y positions and found to be lower than ±1.5% (absolute variation of ±120 nm), within a range of ±15 μm, with respect to the average value on the investigated samples.

The Effects of Load Impedance, Line Length, and Branches in Typical Low-Voltage Channels of the BPLC Systems of Developing Countries: Transmission-Line Analyses

This paper presents the influence of line length, number of branches (distributed and concentrated), and terminal impedances on the performance of a low-voltage broadband power-line communication channel. For analyses, the systems chosen are typical low-voltage power-line networks found in Tanzania. The parameters varied were the network's load impedances, direct line length (from transmitter to receiver), branched line lengths, and number of branches. From the frequency responses of the transfer functions (ratio of the received and transmitted signal), it is seen that the position of notches and peaks in the amplitude responses are affected by the aforementioned network parameters and topology. As a result, the time-domain responses are attenuated and distorted. Time-domain responses of power-line channels under various conditions are also investigated for a given pulse input at the transmitter. The observations presented in this paper could be useful for suitable power-line communication system design.

Current-level discrimination and spectral profile analysis in multi-channel electrical stimulation

In experiment 1, six cochlear-implant (CI) listeners discriminated a stimulation pattern eliciting equal loudness for each electrode from a stimulation pattern in which the stimulation at one or more electrodes was increased (peak) or decreased (notch). Three cochlear locations and three bandwidths were tested, without and with level roving. Listeners could always detect peaks but not always notches. Increasing the bandwidth beyond two electrodes produced no improvement in just-noticeable differences (JNDs). JNDs for the basal location were higher than for the apical and middle locations, although listeners had highly individual tendencies. In experiment 2, listeners discriminated changes in the peak heights and notch depths. JNDs for higher peaks were better while JNDs for deeper notches were worse than for experiment 1. In experiment 3, listeners discriminated the electrode position of peaks or notches. JNDs were approximately one electrode. In experiment 4, the first three experiments were repeated with large amounts of level roving. There was no evidence that CI listeners performed an across-channel comparison in these tasks.

Numerical Analysis of the Effects of Pinna Shape and Position on the Characteristics of Head‐Related Transfer Functions

There are distinctive notches and peaks in Head‐Related Transfer Functions (HRTFs). Some of them are considered as important cues in the perception of the elevation angle and thus the roles of these peaks and notches should be clarified. It is known that the characteristics of HRTFs are deeply related to listener's anthropometry. It is thus naturally expected that frequencies of the peaks and notches also change according to the individuality of listeners' anthropometry. Therefore, in this study, effects of ear shapes and positions on frequency positions of the peaks and notches are examined by numerical analyses. The analysis was performed with boundary element method (BEM). A three‐dimensional model of a dummy‐head was constructed with a three‐dimensional laser scanner and HRTFs of the model were numerically computed with a BEM solver. The model was modified on some features as follows: 1) pinna position, 2) pinna size, 3) angle of pinna toward listener's head, and 4) existence of wrinkles of pinna. HRTFs of the modified models were also computed. From the comparison among the results of calculation, several systematic changes were found. For example, the frequency position of notches around 8 kHz is shifted toward lower frequency as the size of pinna increases.

The Influence of Load Impedance, Line Length, and Branches on Underground Cable Power-Line Communications (PLC) Systems

An underground cable power transmission system is widely used in urban low-voltage power distribution systems. In order to assess the performance of such distribution systems as a low-voltage broadband power-line communication (BPLC) channel, this paper investigates the effects of load impedance, line length, and branches on such systems, with special emphasis on power-line networks found in Tanzania. From the frequency response of the transfer function (ratio of the received and transmitted signals), it is seen that the position of notches and peaks in the magnitude are largely affected (observed in time-domain responses too) by the aforementioned network configuration and parameters. Additionally, channel capacity for such PLC channels for various conditions is investigated. The observations presented in this paper could be helpful as a suitable design of the PLC systems for better data transfer and system performance.

Tidal notches in Vinodol Channel and Bakar Bay, NE Adriatic Sea: Indicators of recent tectonics

Detailed mapping of coastline in Vinodol Channel and adjacent bays in the Kvarner area (Northern Adriatic Sea) revealed the existence of well expressed submerged notches ranging in their elevation from 45 to 115 cm below mean sea level. Noticeable difference in the height of these presumably coeval tidal notches is attributed to neotectonic movements since the Roman times. The difference of ∼ 0.1 m on opposite parts of Vinodol Channel is in accordance with the presumed thrusting tectonics in the adjacent Vinodol Valley. The deeper position of coeval tidal notches in Bakar Bay (the drowned part of Vinodol Valley) indicates it is the tectonically most active zone. Investigation of tidal notches in this case complements information from the solid rock geology and measurements of recent tectonic movements revealed by GPS positioning. Moreover, it indicates the potential of detailed mapping of tidal notches for neotectonic research in some coastal areas.

The Effects of Load Impedance, Line Length, and Branches in the BPLC—Transmission-Line Analysis for Indoor Voltage Channel

This paper presents the effects of load impedance, line length and branches on the performance of an indoor voltage broadband power line communications (BPLC) network. The power line network topology adopted here is similar to that of the system found in Tanzania. Different investigations with regard to network load impedances, direct line length from transmitter to receiver, branched line length, and number of branches has been carried out. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude and phase responses are largely affected by the above said network parameters/configuration, mainly in terms of attenuation and dispersion. These effects are observed in the time domain responses also. The observations presented in the paper could be helpful in the suitable design of the BPLC systems for a better data transfer and system performance.

The Effects of Load Impedance, Line Length, and Branches in the BPLC—Transmission-Lines Analysis for Medium-Voltage Channel

This paper presents the effects of load impedance, line length and branches on the performance of medium-voltage power-line communication (PLC) network. The power-line network topology adopted here is similar to that of the system in Tanzania. Different investigation with regard to network load impedances, direct line length (from transmitter to receiver), branched line length and number of branches has been investigated. From the frequency response of the transfer function (ratio of the received and transmitted signal), it is seen that position of notches and peaks in the magnitude and phase responses are largely affected in terms of attenuation and dispersion by the above said network parameters/configuration. These are observed in the time domain responses too. The observations presented in the paper could be helpful in suitable design of the PLC systems for a better data transfer and system performance.

Analysis of Contact Singular Stresses with Relief Notch by Using Dynamic Photoelasticity(II)

The dynamic photoelastic technique had been utilized to investigate the possibillity of relieving the large local singular stresses induced at the corner of a right- angle- indenter. The indenter compressed a semi-infinite body dynamically with an impact load applied on the top of the indenter. The effects of the geometric changes of the indenter in terms of the diameter (d) and the location (1) of the stress relieving notch on the behavior of the dynamic contact stresses were investigated. The influence of stress relieving notches positioned along the edge of the semi-infinite body on the dynamic contact stresses were also studied by changing the diameter (D) and the location (L) of the notch. A multi-speak-high speed camera with twelve sparks were used to take photographs of full field dynamic isochromatic fringe patterns. The contact singular stresses were found to be released significantly by the stress relief notches both along the indenter and the edge of the semi-infinite body. The optimal position and geometry of the stress relieving notches were obtained with the aid of limited experimental results.

Nontraditional cutting for ceramic plates with elastic working.

In this paper, two cutting methods for ceramic plates with elastic working are proposed. Both methods are applications which take advantage of the results of bending fractured brittle materials. In our experiments, ceramic materials such as alumina, zirconia, sialon, and others, were cut along precise cut lines by making notches on the surface of these ceramic materials before cutting. By using this procedure, we were able to produce cut surfaces that were precisely perpendicular to the surface of the plate, and in the exact position of the original notches. The significant characteristics of both methods are that the cutting was done without generating any dust, the amount of energy required was very small, and the time required for the cutting process was very short.

The Effect of Notches at the Tooth Root Fillet on the Endurance Strength of Gears

Notches at the tooth root fillet can be caused by shaving or grinding. The influence of different notches at the root fillet on the endurance strength of case hardened spur gears was investigated in back-to-back tests and pulsator tests. Data of the test gears: MnCr and CrNi Steels, module 3 (8 DP) and module 8 (3 DP). Besides the a.m. tests photo elastic investigations were performed. On the basis of some characteristic parameters, it was possible, to find a calculation procedure, to determine the loss of endurance strength due to the effect of various kinds of notches. Moreover it was investigated to what extent the endurance strength of notched gears could be increased by regrinding or shot peening the root fillet. It is known that notches at the tooth root fillet can essentially reduce the endurance strength of gears. This is of special importance for case hardened gears. It is desirable that such notches should be avoided, but sometimes notches are produced by shaving or grinding due to inadequacy of tooling or non-uniform heat distortion. Therefore the influence of geometry and position of notches at the root fillet on the endurance of case hardened spur gears was investigated in back-to-back and pulsator tests. Additionally the extent the endurance strength of notched gears could be increased by regrinding or shot peening the root fillets was studied.