Miracle-dz/UniFAR-FTUs huggingface dataset:
Compressive, tensile and bending basic creep behaviours related to the same concrete

This paper concerns the relationship between compressive, tensile and flexural creep behaviours related to the same concrete. Experimental tests and a numerical simulation are performed in the scope of this work. The main conclusion of this study is that due to the strong scale effect related to the tensile and bending creep behaviours of a “standard” concrete mix design, it is not possible to simulate numerically (with classical Kelvin‐Voigt chains) the bending creep behaviour of that type of concrete knowing the compressive and tensile creep behaviours obtained using the specimen geometries normally used in laboratories.
Modified linear and circular carrier-frequency Fourier-transform method applied for studies of vibrating microelements

Stroboscopic interferometry is the most popular method for investigation of active, vibrating elements. The interferograms obtained in measurement steps may be analysed by temporal phase shifting method or by spatial carrier frequency methods. The first one requires sequential capturing of phase-shifted interferograms which complicates the measurement system and introduces high stability requirements for the setup. The spatial methods need a single interferogram with a proper spatial carrier frequency (SCF), so they are more suitable for dynamic events analysis. The most frequently used spatial method is based on Fourier transform of an interferogram with linear SCF and can be applied to analysis of restricted class of elements represented by quasi-linear fringes. This can be easily expanded by considering elements with circular carrier fringes (CCF). In the paper two approaches to analysis of interferograms with CCF, namely: coordinate transform Fourier transform technique and direct filtering Fourier transform technique are explained. The error analysis of both techniques applied for different classes of interferograms is presented. The methodology of CCF interferogram analysis based on FT methods applied for micromembranes is presented and several exemplary results are given.
Complementary stacked patch antenna with fractal shape defect for wideband characteristics

A complementary staked microstrip antenna with a modified Minkowski fractal shaped defect is presented which has a wide bandwidth of 1.8–6.4 GHz with a fractional BW of 89.1%. The concept of the complimentary stacked parasitic fractal patch has been incorporated to enhance the impedance bandwidth in comparison to the conventional stacked patch antenna. The antenna has a dimension of 42 × 55 × 4.8 mm3, which is printed on a low cost FR4 substrate of dielectric constant 4 and a height of 1.6 mm. The gain of the antenna varies from 5 to 7 dBi throughout the operating band. Simulated and experimental characteristics of the antenna are in good agreement. The proposed antenna can be a potential candidate for wideband communication systems and also capable to operate satisfactorily in 3.3–3.7 GHz (WiMAX), 3.7–4.2 GHz (C‐Band), and 5.15–5.825 GHz (WLAN) frequency bands. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:944–947, 2014
Unsteady rolling moment characteristics for fighter oscillating with yawing-rolling coupled motion

T HE maneuvering flight of an aircraft is very complicated. It usually consists of coupled motions about three body axes; therefore, it is very important to simulate maneuvering flight and measure the unsteady aerodynamics in the wind tunnel. Simple flight maneuvers such as the cobra maneuver [1] and the wing rock can be simulated easily, and tests have been conducted in many wind tunnels [2,3]. However, for the complicated flight maneuvers, such as theHerbstmaneuver [4], there is a yawing–rolling coupledmotion about the body axes when the aircraft encounters high angles of attack. Up to now, the wind-tunnel test data for such complicated coupled motions are very few. The method of the linear superposition is usually used to calculate the unsteady forces and moments of coupled motion to analyze the maneuvering characteristics of the aircraft. The linear superposition model is suitable at low angles of attack, but whether it is suitable at high angles of attack is still not clear. In [5], Zhongjun and Edward adopted the quasi-steady aerodynamic model and the unsteady aerodynamic model to simulate the coupled motion of the aircraft. The results of the two methods are very different. In this investigation, an aircraft configuration with a strake wing was tested in a 3-m low-speedwind tunnel at NanjingUniversity ofAeronautics and Astronautics (NUAA) with large amplitude oscillation. The unsteadiness of the rolling moment as the model oscillates in a yawing–rolling coupled motion is compared with that of in pure yawing motion and rolling motion. The lateral dynamic derivatives were obtained using a mathematical model with the fuzzy logic algorithm and the dynamic derivative simulation. The unsteady rolling moment for the yawing–rolling coupledmotion was obtained by using the quasi-steady aerodynamic model or the unsteady aerodynamic model, respectively, and the results are compared with the experimental data. It is shown that the wind-tunnel tests can provide better results for the unsteady aerodynamics of coupled motion at large angles of attack.
Numerical Prediction of Rock Fracturing During the Process of Excavation

During the process of excavation, blasting can induce cracking inside the surrounding rock. Considering the effects of material properties and loading conditions, a rock blasting excavation model with two successive excavation steps was developed through the use of AUTODYN code. Four kinds of equation of state (EOS), linear, shock, JWL, and compaction were applied to the materials employed in this numerical model. A modified principal stress failure criterion was applied to determining material statuses, and TNT explosive and a relatively homogeneous igneous rock, diorite, were used in this numerical model. By using this numerical model, rock fracturing process during blasting excavation was simulated, and rock fracturing process during two successive excavations is presented.
Control strategy without phase-locked loop based on coordinate transformation for three-phase AC/DC converter

A novel control strategy without phase-locked loop (PLL) for the three-phase AC/DC converter is proposed in this study. There is no need to detect the phase angle of the grid and the defect of inaccurate phase-locking can be remedied. The frequency of the grid can be detected by a frequency tracking method. A linear changed angle from −π to π with the detected grid frequency is generated by the DSP controller to take part in the coordinate transformation. The grid frequency tracking method is realised by negative feedback of reactive power. It can ensure that the frequency of the linear changed angle is the same as the grid frequency. The principle of the proposed control strategy is analysed in details. Compared with the control strategy with PLL, the proposed control strategy does not need complex PLL and it can realise high power factor and low total harmonic distortion in the non-ideal grid. The structure of the proposed grid frequency tracking method is established and the parameters of it are designed. An 18 kW DSP-based bidirectional three-phase AC/DC converter is established. Simulation and experimental results verify theoretical analysis.
Volterra series analysis of distortion in semiconductor laser diodes

A frequency domain analytic study of laser nonlinear distortion is presented, based on the Volterra nonlinear functional series. This analysis is shown to predict all the intermodulation products up to third order, of particular relevance to the design of subcarrier multiplexed systems, when the laser is modulated by an arbitrary number of channels. Illustrative analytic and simulation results are presented for two and three input subcarriers and are shown to match very closely.
A semi-empirical model for the field-effect mobility of hydrogenated polycrystalline-silicon MOSFETs

The quantitative relationship between field-effect mobility ( mu /sub FE/) and grain-boundary trap-state density (N/sub t/) in hydrogenated polycrystalline-silicon (poly-Si) MOSFETs is investigated. The focus is on the field-effect mobility in MOSFETs with N/sub t/ 1*10/sup 2/ cm/sup -2/. It is found that reducing N/sub t/ to as low as 5*10/sup 11/ cm/sup -2/ has a great impact on mu /sub FE/. MOSFETs with the N/sub t/ of 4.2*10/sup 11/ cm/sup -2/ show an electron mobility of 185 cm/sup 2//V-s, despite a mean grain size of 0.5 mu m. The three principal factors that determine mu /sub FE/, namely, the low-field mobility, the mobility degradation factor, and the trap-state density N/sub t/ are clarified. >
A Survey on Change Detection and Time Series Analysis with Applications

With the advent of the digital computer, time series analysis has gained wide attention and is being applied to many fields of science. This paper reviews many traditional and recent techniques for time series analysis and change detection, including spectral and wavelet analyses with their advantages and weaknesses. First, Fourier and least-squares-based spectral analysis methods and spectral leakage attenuation methods are reviewed. Second, several time-frequency decomposition methods are described in detail. Third, several change or breakpoints detection methods are briefly reviewed. Finally, some of the applications of the methods in various fields, such as geodesy, geophysics, remote sensing, astronomy, hydrology, finance, and medicine, are listed in a table. The main focus of this paper is reviewing the most recent methods for analyzing non-stationary time series that may not be sampled at equally spaced time intervals without the need for any interpolation prior to the analysis. Understanding the methods presented herein is worthwhile to further develop and apply them for unraveling our universe.
The code SG99 for high-power laser propagation and its applications

In this paper, the physical models of the code SG99, which is used to simulate the pulse behavior in high power laser system, are presented in details. The experimental results are also presented to show that SG99 is capable of simulating pulse propagation well and yields reasonable results. In the last, some results in design of TIL(Technical Integrated Experiment Line), the prototype of ShenGuangIII, are also introduced.
Performance analysis for MIMO systems using zero forcing detector over fading channels

In the paper, the performance of multiple-input-multiple-output (MIMO) systems using a zero forcing detector is studied over Rayleigh and Rice fading channels. Approximation to the distribution of non-central complex Wishart distribution is used to derive the distribution of the post-detection signal-to-noise (SNR) ratio. A closed-form expression of bit error rate is obtained in terms of the hypergeometric and Gamma functions. The performance of MIMO systems under the scenario that the individual sub-channels are correlated is also investigated. It is shown that, for the exponential correlation channel model, an increase in channel correlation between the transmission paths results a decrease in SNR at the receiver. It is concluded that with the same SNR at the receiver, the performance of MIMO systems over a Rice fading channel degrades compared to that over an independent and identical distributed (i.i.d.) Rayleigh fading channel.
Effect of Nitrogen Fertilizer Levels on Grain Yield, N Uptake and N Use Efficiency of Malt Barley (Hordeum Vulgare L.) Varieties at Wolmera District, Central Highland of Ethiopia

A field experiment was carried out during the 2017 cropping season at Holetta Agricultural Research center to determine the effect of nitrogen fertilizer levels on grain yield and quality of malt barley ( Hordeum vulgare L.) varieties at Wolmera district, central highland of Ethiopia. The treatments include a factorial combination of four nitrogen levels (0, 18, 36, and 54 kg Nha -1 ) and four malt barley varieties (Holker, Ibon174/03, HB-1963, and Explorer). The experiment was laid in a randomized complete block design with three replications. The higher (6170.70 kgha -1 ) grain yield were obtained with the combination of Ibon174/03 variety and application of 36 kg N/ha. The highest (130kgha -1 ) grain N uptake were recorded with combination of HB-1963 variety and application of 54 kg N/ha rates, while the lowest (47kgha -1 ) grain N uptake were obtained with combination of control treatment and Explorer variety. The highest nitrogen use efficiency (327.03%) was recorded with the combination of 18 kgha -1 N fertilizer along with Ibon174/03 variety. The highest net benefits (49,015.45 EBha -1 ) with marginal rate of return (136%) were obtained from the combination of 36 kg Nha -1 with Ibon174/03 variety. Therefore, application of 36 kg Nha -1 fertilizer rates and Ibon174/03 variety was found to be better both agronomically and economically feasible for malt barley production in Wolmera area. Keywords : Nitrogen fertilizer, Nitrogen uptake, Nitrogen use efficiency and Variety
Piezoelectric micromachined ultrasonic transducers with rectangular diaphragms for dual-frequency applications

Piezoelectric micromachined ultrasonic transducer (pMUT) consisting of a piezoelectric capacitor built on a micromachined silicon membrane has been used for ultrasound transmitting and sensing. It typically operates at the fundamental flexural vibration frequency, where maximum sensitivity can be achieved, and is insensitive at higher order of resonances because the harmonic signals generated from different parts of the diaphragm tend to cancel with each other. This leads to a very narrow bandwidth. In this paper, rectangular-shaped pMUTs for dual-frequency application are proposed and fabricated using piezoelectric P(VDF-TrFE) copolymer coating and silicon micromachining technologies. The electrode patterns are properly designed to efficiently make use of both (0, 0) and (2, 0) vibration modes of the rectangular membrane. By adjusting the length and width of the diaphragm, the ratio of the two frequencies can be varied on demand within a wide range. The corresponding design principles are also useful for other micromachined devices such as surface acoustic wave devices, delay lines, resonators, etc.
Exploitation of reciprocity in measured mimo channels

In this work we study the feasibility of relative calibration to exploit channel reciprocity in a multipleinput multiple-output (MIMO) time division duplex (TDD) system. As an extension to the work of Guillaud et al. (2005), where the method was only applied to SISO and SIMO channels, real two-directional channel measurements were performed using the Eurecom MIMO Openair Sounder (EMOS). The setup considered here is more realistic, since a faster repetition rate, synchronization of transmitter and receiver over the air, and frequency offset, are accounted for. One of the major findings in the paper is a modification to the system model that correctly describes the non-negligible phase drift present in the measurements. We demonstrate that in a single-user MIMO channel and for low signal-to-noise (SNR) ratios, the relative calibration method can increase the capacity close to the theoretical limit.
Aircraft corrosion and crack inspection using advanced magneto-optic imaging technology

A next generation magneto-optic imaging system, the MOI 303, has recently been introduced with the ability to generate real-time, complete, 2D eddy current images of cracks and corrosion in aircraft. The new imaging system described features advanced, digital remote control operation and on- screen display of setup parameters for ease of use. This instrument gives the inspector the capability to more rapidly scan large surfaces areas. The magneto-optic/eddy current imaging technology has already been formally approved for inspection of surface cracking on an aircraft fuselage. The improved magneto-optic imager is now poised to aid rapid inspection for corrosion and subsurface cracking. Previous magneto-optic imaging systems required the inspector to scan the surface twice for complete inspection coverage: a second scan was necessary with the imager rotated about 90 degrees from the orientation of the first pass. However, by providing eddy current excitation simultaneously from two orthogonal directions, complete, filled-in magneto-optic images are now generated regardless of the orientation of the imager. THese images are considerably easier to interpret and evaluate. In addition, there is a synergism obtained in applying eddy current excitation simultaneously in multiple directions: better penetration is obtained and the resulting images have better signal to noise levels compared to those produced with eddy current excitation applied only in one direction. Examples of these improved images are presented.
Human Hand Model Calibration Using 3D Reconstruction From Multiple Silhouette Views

As real-time performance of 3D graphics machines is achieved the ability to interact more naturally with synthetic 3D scenes is needed. Humans manipulate objects in a spatial environment most easily with their hands and the same should be true for synthetic 3D scene manipulation. Thus, a system is needed for recognition of human hand position and configuration which does not encumber hand movement. This paper describes a system which computes a 3D reconstruction from multiple camera views of a human hand. A polyhedron synthetic model of the human hand is then modified to most closely match the size and shape of the reconstructed human hand. Ulti-mately, the calibrated hand model will be used in a real-time model-based hand configuration recognition system. This system will include multiple cameras and back-lighting surrounding a convenient hand working space of perhaps one cubic meter. In order to manage the combinatorial explosion of all possible hand configurations, the hand model is divided into components (fingers, thumb and palm) and all possible configurations of the individual components are stored. Hand configuration recognition will be achieved by hierarchical partial matches of hand model components to the reconstructed user's hand. The search for the best matching hand model configuration will be limited by assuming a maximum possible range of hand component movements from frame to frame. Preliminary results from model-based hand configuration recognition experiments will be shown and methods for real-time implementation of the system will be discussed.
Switched-capacitor power electronics circuits

One of the main orientations in power electronics in the last decade has been the development of switching-mode converters without inductors and transformers. Light weight, small size and high power density are the result of using only switches and capacitors in the power stage of these converters. Thus, they serve as ideal power supplies for mobile electronic systems (e.g. cellular phones, personal digital assistants, and so forth). Switched-capacitor (SC) converters, with their large voltage conversion ratio, promise to be a response to such challenges of the 21st century as high-efficiency converters with low EMI emissions and the ability to realize steep step-down of the voltage (to 3 V or even a smaller supply voltage for integrated circuits) or steep step-up of the voltage for automotive industry or Internet services in the telecom industry. This paper is a tutorial of the main results in SC-converter research and design.
Domain decomposition methods for simulation of printing and inspection of phase defects

A detailed study of the domain decomposition method by edges (edge-DDM) is used to show the smallest feature sizes that can be accurately simulated using the decomposition, and thereby understand the domain of applicability for this simulation method during printing. For features in arbitrary layouts, edge-DDM is accurate to better than 1% for any mask lateral feature dimension of 2l or longer. The smallest feature dimension could be even smaller, depending on the types of edges present in the layout. Design graphs are produced to show the smallest feature dimension for any specific layout. In general, the TE polarization limits the edge-DDM applicability, and extensions to model the boundary interactions at small CDs may be able to reduce the smallest feature dimension to equal that of the TM polarization, resulting in a 1 - 1.5 λ minimum dimension. A 'defect projector' method for rapidly and accurately simulating defect printability is introduced and combined with edge-DDM. Calculations of the CD change from the defect projector method agree with calculations of CD change from rigorous simulations with embedded defects to within 30%, despite low NILS values from the test structure used in this study. Finally, the impacts on edge-DDM accuracy for both off-axis illumination and the larger numerical apertures utilized during inspection are investigated. Results show that high spatial frequency errors resulting from edge-DDM synthesis of the near fields are problematic for inspection. Asymptotic anticipation is suggested for modeling the high frequency components.
Electrical Model of Inside Sense Outside Drive Frame Micro-Gyroscope Including Quadrature Error and Coriolis Offset

Quadrature error and Coriolis offset are main errors of micro-gyroscopes which caused by manufacturing imperfections. They deteriorate the overall performance of micro-gyroscopes. For inside sense outside drive frame micro-gyroscope, quadrature error and Coriolis offset have their own characters. Based on the mechanical analysis of inside sense outside drive frame micro-gyroscope in imperfect condition, the dynamic equations of condition with quadrature error and Coriolis offset are investigated, and an equivalent electrical model with quadrature error and Coriolis offset is presented. It is convenient to observe the effect of quadrature error and Coriolis offset by equivalent electrical model simulating. Three conditions are simulated and compared. The results indicate that the Coriolis offset reduces the amplitude of instantaneous displacement to a very small extent. Its effect can be neglected. Quadrature error causes an error displacement with the amplitude much bigger than the prefect displacement’s amplitude. It is the overwhelming error in ISOD frame micro-gyroscope.
Strategic Decisions

In Strategic Decisions, Planellas and Muni provide an invaluable tool for anyone facing the challenge of taking strategic decisions. Using their 'circle of strategic decisions' framework, they guide readers smoothly through the decision-making process. Following this, they present thirty of the most widely used strategic models, including Porter's Five Forces, Ansoff's Matrix, Blue Ocean Strategy, Open Innovation, and the 8-Step Change Model. For each model, they demonstrate the content, context, and application, using clear and eye-catching graphics. This is a must-have book for all M.B.A. students and business managers.
In-service Teachers' Attitudes Towards Technology Integration in the Bahraini Classroom

In order for Bahrain to realize its 2030 Economic Vision, digital literacy is required on the part of its citizens. Digital literacy is the ability to make use of Information and Computer Technology (ICT) in learning and work activities (Erstad 2006; Krumsvisk 2006) , and can be understood clearly by understanding the role of ICT in schools (Hadjerrouit 2008) . Such a role is successfully implemented mainly when certain conditions are met, among them the adoption of a positive attitude towards the utilization and integration of ICT in instruction on the part of the teachers. This study examines to what extent teachers in the Bahraini public school system adopt such an attitude, while at the same time (1) focusing on the amount of support they receive in terms of ICT training and resources and (2) identifying shortcomings that need to be addressed for successful ICT integration in teaching and learning.