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1
Gołębiowski, Jerzy, and Marek Zaręba. "Analytical modelling of the transient thermal field of a tubular bus in nominal rating." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 38, no. 2 (March 4, 2019): 642–56. http://dx.doi.org/10.1108/compel-02-2018-0078.
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Purpose The purpose of this paper is to analyse the dynamics of a thermal field generated in a tubular bus with rated current by using two models of electrical resistivity of copper. Design/methodology/approach The boundary-initial problem of the modified heat equation was formulated for the tubular bus. Analytical solutions were obtained by means of Green’s functions as the kernels of the integral operator inverse to the corresponding differential operator. The results were presented graphically and verified using the finite element method. The calculations were made by considering the example of the Storm Power Components tubular bus (USA). Findings Analytical field models were used to determine time- and space-variable heating curves, time constants and steady-state current ratings. Research limitations/implications This paper is related to the structure of a hollow cylinder. Other bus sections can be taken into account by using the coordinate systems of different curvilinear orthogonal symmetry. Originality/value Using the analytical method, the influence of the variable (temperature dependent) electrical resistivity on some important parameters and characteristics of the tubular bus was investigated. The system was considered as an element with distributed parameters.
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Tasic, Bratislav, Jos J. Dohmen, E. Jan W. ter Maten, Theo G.J. Beelen, Wil H.A. Schilders, Alex de Vries, and Maikel van Beurden. "Robust DC and efficient time-domain fast fault simulation." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 33, no. 4 (July 1, 2014): 1161–74. http://dx.doi.org/10.1108/compel-12-2012-0364.
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Purpose – Imperfections in manufacturing processes may cause unwanted connections (faults) that are added to the nominal, “golden”, design of an electronic circuit. By fault simulation one simulates all situations. Normally this leads to a large list of simulations in which for each defect a steady-state (direct current (DC)) solution is determined followed by a transient simulation. The purpose of this paper is to improve the robustness and the efficiency of these simulations. Design/methodology/approach – Determining the DC solution can be very hard. For this the authors present an adaptive time-domain source stepping procedure that can deal with controlled sources. The method can easily be combined with existing pseudo-transient procedures. The method is robust and efficient. In the subsequent transient simulation the solution of a fault is compared to a golden, fault-free, solution. A strategy is developed to efficiently simulate the faulty solutions until their moment of detection. Findings – The paper fully exploits the hierarchical structure of the circuit in the simulation process to bypass parts of the circuit that appear to be unaffected by the fault. Accurate prediction and efficient solution procedures lead to fast fault simulation. Originality/value – The fast fault simulation helps to store a database with detectable deviations for each fault. If such a detectable output “matches” a result of a product that has been returned because of malfunctioning it helps to identify the subcircuit that may contain the real fault. One aims to detect as much as possible candidate faults. Because of the many options the simulations must be very efficient.
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Athavale, M. M., and R. C. Hendricks. "A Small Perturbation CFD Method for Calculation of Seal Rotordynamic Coefficients." International Journal of Rotating Machinery 2, no. 3 (1996): 167–77. http://dx.doi.org/10.1155/s1023621x96000048.
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Seal rotordynamic coefficients link the fluid reaction forces to the rotor motion, and hence are needed in the stability calculations for the overall rotating systems. Presented in this paper is a numerical method for calculations of rotordynamic coefficients of turbomachinery seals with rotors nominally at centered, eccentric and/or misaligned position. The rotor of the seal is assumed to undergo a prescribed small whirling motion about its nominal position. The resulting flow variable perturbations are expressed as Fourier functions in time. The N-S equations are used to generate the governing equations for the perturbation variables. Use of complex variables for the perturbations renders the problem quasi-steady. The fluid reaction forces are integrated on the rotor surface to obtain the fluid reaction forces at several different whirl frequencies. The rotordynamic coefficients are calculated using appropriate curve fitting. Details of the model are presented, and sample results for concentric and eccentric annular incompressible flow seals are included to demonstrate the capability and accuracy of the proposed method.
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McDaniel, James G., and Allison Kaminski. "Surrogate models of complex dynamic systems from energy distributions." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A134. http://dx.doi.org/10.1121/10.0015795.
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Engineers who design complex dynamic systems do not have the luxury of iteration. Numerical analysis of a single design, typically by finite element analysis, requires enormous amounts of CPU time. Therefore, improving a design by trying out many design modifications is impossible. Moreover, it is also impossible to identify which subsystem designs have the largest effects on the dynamic response of the system. The present work addresses this challenge by constructing surrogate models from energy distributions in a nominal design. These surrogate models are surprisingly effective at identifying subsystems that have the largest effects on the dynamic response, and therefore guide engineers to design modifications that matter most. A significant advantage of these surrogate models is the very low cost of creating them, as they are created directly from the frequency response of a nominal design and therefore do not require additional linear solves or other time-intensive calculations. This presentation begins with an analytical justification for considering energy distributions as surrogate models. Next, Monte Carlo Simulations are presented to show strong correlations between energy distributions and the effects of design changes on dynamic responses. These simulations include random structures as well as beams. Work supported by ONR under Grant N00014-19-1-2100.
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Dems, Maria, Krzysztof Komeza, Slawomir Wiak, and Sara Fernández Coya. "Influence of the closing rotor slots on the additional losses in the induction motor." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 34, no. 2 (March 2, 2015): 531–49. http://dx.doi.org/10.1108/compel-07-2014-0183.
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Purpose – The purpose of this paper is to present the distribution of the magnetic field and additional losses analysis of the induction motors (IM) with opened and closed rotor slots. Design/methodology/approach – In the field-circuit approach the distribution and changes of magnetic flux density in the motor are computed using a time-stepping finite element method. The additional losses in each element are evaluated at different frequencies. Findings – An approximate analytical formulation is derived for rapid losses computation confirmed by the results of field-circuit method. For high-voltage motors due to the size ratios of the core and relatively deep stator and rotor slots major role in causing loss of higher harmonics play a fundamental slot harmonics. Higher harmonics order bigger than 100 cause only small part of total higher harmonics core losses. Closed rotor slots construction influenced significantly on no-load losses mainly due to reduction of losses at slot upper part. For nominal load condition that influence is not so strong according to the saturation of slot tips by rotor leakage flux. Nevertheless, core losses at load are several times higher as at no-load. Research limitations/implications – In future research authors will take into account motors feed from PWM inverter, working in the frequency range up to 400 Hz. Practical implications – The results of investigation will be used in more detailed design of IMs especially for motors with closed rotor slots. Originality/value – The methods presented in the paper was not used before. Also results of additional losses in the motor core calculation, especially according motors with closed slots at no load and load conditions are new.
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Mason, Paul M., and Andres Gallo. "An Alternative Estimation Technique for Determining Discount Rates and Earnings Growth Rates in Wrongful Death and Personal Injury Cases." Journal of Forensic Economics 26, no. 2 (December 1, 2016): 181–92. http://dx.doi.org/10.5085/jfe-397.1.
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Abstract Regardless of the time period studied since the 1970s ended, without adjustments for structural factors, both real and nominal interest rates across the spectrum of maturities exhibit non-stationary processes with a unit root. Consequently, simply employing past means of either real or nominal yields losses a degree of credibility. Focusing on the period of the “Great Moderation,” employing structural break analysis can remove the non-stationarity so that forensic economists can chose not to use more complex ARIMA models, stochastic properties of interest rates, or estimating methods more complex than these. Rather, following the analysis in this paper, forensic economists can employ one of a small number of discount rates from a not too distant past time period that reflect systematic variations more likely to be consistent with predictable future interest rates.
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Kim, Sang Su. "A Priching Model for Inflation-indexed Bonds." Journal of Derivatives and Quantitative Studies 19, no. 2 (May 31, 2011): 175–206. http://dx.doi.org/10.1108/jdqs-02-2011-b0003.
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This paper derives the theoretical price of nominal bonds and inflation-indexed bonds through extracting the factors, which are assumed that their stochastic property follows the standard O-U process, in the term structure of nominal interest rates and yields of inflation-indexed bonds by the Principal Component Analysis (PCA). In particular, through reflecting the complex structure of inflation-indexed bonds by accurately applying theoretical price, it brought differentiation from other literatures, and applied this pricing model to Japanese Government Inflation-indexed Bond (JGB) data. The empirical results of above model show that explanation of time series and cross section of Janpan's real and nominal interest rates were outstanding and was found that Fisher hypothesis was rejected in further
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Fabbri, Massimo, Pier Luigi Ribani, and Davide Zuffa. "Design and testing of a magnetic suspension for a 90° horizontal bend conveyor." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 34, no. 1 (January 5, 2015): 380–96. http://dx.doi.org/10.1108/compel-02-2014-0049.
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Purpose – A conveyor device is studied with the aim to reduce the friction between the inner surface of the beam and the chain. The lower is the friction between the chain and the beam, the lower is the surface wear. The magnetic repulsion force among permanent magnets (PMs) placed on the beam and on the chain is utilized to reduce friction. The paper aims to discuss these issues. Design/methodology/approach – The considered magnetic suspension is realized with PMs in repulsive configuration; it is designed by solving a constrained optimization problem, with reference to the geometry of the 90° horizontal bend FlexLink WL322 conveyor. Flux density field and its gradient are evaluated using volume integral equation method, allowing to calculate the forces acting on the chain and the stiffness of the magnetic suspension. Findings – The magnetic suspension prototype was manufactured and tested. The experimental and calculated values of the forces acting on the chain compares well. A stable horizontal equilibrium of the chain was obtained during both static and dynamical tests. Research limitations/implications – The quasi-static model used neglects the dynamical interactions among the elements of the chain, the PMs and loads weight during motions and the eddy current losses in the aluminium beam. However the dynamical tests on the prototype show that the chain motion is regular up to the nominal velocity all along the conveyor with the exception of the trailing edge of the 90° curve. Practical implications – The tests on the prototype show the possibility of a removal or at least a reduction of the friction force between the chain and the inner side of the beam by means of a passive magnetic suspension. As a consequence a reduction of noise and vibrations and an increase of the mean-time-to-failure is expected. Originality/value – Prototype testing shows that the unavoidable vertical instability of the magnetic forces has no practical consequence since, reducing the allowed vertical gap, the chain is stabilized by the gravitational force.
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Młot, Adrian, and Marian Łukaniszyn. "Analysis of axial flux motor performance for traction motor applications." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 38, no. 4 (July 1, 2019): 1306–22. http://dx.doi.org/10.1108/compel-10-2018-0401.
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Purpose Analysis of test data monitored for a number of electric machines from the low volume production line can lead to useful conclusions. The purpose of this paper is to trace the machine performance to find quality-related issues and/or identify assembly process ones. In this paper, the monitoring of experimental data is related to the axial flux motor (AFM) used in hybrid electric vehicle (HEV) and in electric vehicle (EV) traction motors in the global automobile market. Design/methodology/approach Extensive data analyses raised questions like what could be the causes of possible performance deterioration of the AFM and how many electric motors may not pass requirements during operation tests. In small and medium research units of AFM for HEV or EV, engineers came across a number of serious issues that must be resolved. A number of issues can be eliminated by implementing methods for reducing the number of failing AFMs. For example, improving the motor assembly precision leads to reduction of the machine parameters deterioration. Findings Assembly tolerances on electric motor characteristics should be investigated during motor design. The presented measurements can be usable and can point out the weakest parts of the motor that can be a reason for the reduced efficiency and/or lifetime of the AFM. Additionally, the paper is addressed to electric motor engineers designing and/or investigating electric AFMs. Originality/value Performance of AFM was monitored for a number of identical motors from low volume production line. All tested motors were operated continuously for a long period of time and the tests were repeated every few weeks for half a year to check the reliability of motor design and indicate how much the motor parameters may change. The final results point how many motors fail the requirements of motor performance. A few batches of AFM were selected for testing. Each batch represents a different size (nominal power) of the same type of AFM.
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Sinkevich, Mikhail, Eldar Ramazanov, and Anatoliy Kosoy. "Conceptual methods of starting and controlling operating modes of compressorless combined cycle gas turbine unit." E3S Web of Conferences 289 (2021): 02005. http://dx.doi.org/10.1051/e3sconf/202128902005.
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A method for operation study of a compressorless combined-cycle gas turbine (CCCGT) unit during transients from one steady-state mode to another, including during start-up and shutdown, is proposed. As an example, studies of the transients of an energy complex with a capacity of 60 MW are given. A variant of an algorithm concept for start/stop and transients of such an energy complex is proposed. This concept includes algorithms for starting from the three initial states of the energy complex (cold, hot and standby). For these algorithms, the time and energy consumption characteristics are estimated. It is shown that from a cold state, such an energy complex can be started and brought to the nominal mode in 1.5-2 hours. At the same time, the energy costs will not exceed energy consumption for its own needs in a nominal mode. The start-up time from the hot state can be reduced to 20-25 minutes, and the start-up from the standby state can be 2.5-3 minutes. The proposed concept of control algorithms for transient modes is such, so that a temperature state of the main components and parts of the energy complex is provided at a constant temperature. Thus, the time of transients will be determined only by the speed of the regulatory authorities. Consequently, power systems operating on the CCCGT cycle can operate equally efficiently, both in the basic mode and in the power control mode.
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DALE, RICK, ANNE S. WARLAUMONT, and DANIEL C. RICHARDSON. "NOMINAL CROSS RECURRENCE AS A GENERALIZED LAG SEQUENTIAL ANALYSIS FOR BEHAVIORAL STREAMS." International Journal of Bifurcation and Chaos 21, no. 04 (April 2011): 1153–61. http://dx.doi.org/10.1142/s0218127411028970.
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We briefly present lag sequential analysis for behavioral streams, a commonly used method in psychology for quantifying the relationships between two nominal time series. Cross recurrence quantification analysis (CRQA) is shown as an extension of this technique, and we exemplify this nominal application of CRQA to eye-movement data in human interaction. In addition, we demonstrate nominal CRQA in a simple coupled logistic map simulation used in previous communication research, permitting the investigation of properties of nonlinear systems such as bifurcation and onset to chaos, even in the streams obtained by coarse-graining a coupled nonlinear model. We end with a summary of the importance of CRQA for exploring the relationship between two behavioral streams, and review a recent theoretical trend in the cognitive sciences that would be usefully informed by this and similar nonlinear methods. We hope this work will encourage scientists interested in general properties of complex, nonlinear dynamical systems to apply emerging methods to coarse-grained, nominal units of measure, as there is an immediate need for their application in the psychological domain.
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Pavlov, V. E. "Study of operational modes of an "electric drive–turbomachinery–pipeline" technological complex." iPolytech Journal 26, no. 2 (July 5, 2022): 284–96. http://dx.doi.org/10.21285/1814-3520-2022-2-284-296.
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A developed mathematical model of an asynchronous motor – turbomachinery pipeline technological complex is presented. An analysis of starting conditions is carried out by a nonlinear differential calculus and graphic analytical method. The calculations for the model were performed using the MATLAB software package. The flow, head, efficiency of the pump mechanism and entire pump unit, stator current, angular frequency and torque of the asynchronous motor were calculated at pump start-up and with an increase of pipeline resistance coefficient by 2, 5, 10, and 1000 times. At an increase in the pipeline resistance coefficient by 10 times, the pump efficiency is shown to be reduced by 2.8 times, while the head is increased by 1.28 times; meanwhile, the torque, stator current, and rotational speed of the asynchronous motor change insignificantly. The torque and current decrease by 1.167 and 1.034 times, respectively, while the speed increases by 1.0046 times; the efficiency of the pump mechanism and pump assembly (including motor) decreases by 1.78 and 1.89 times, respectively. The start-up time of the pump motor equals 0.5 s; the maximum stator current at start-up exceeds the nominal value by 4.39 times; the steady-state stator current comprises no more than 59.3 % of the nominal value. The developed mathematical model of the asynchronous motor – turbomachinery – pipeline technological complex is established to allow the operational and energy parameters of the unit to be quantitatively estimated at start-up, while the pump capacity is capable of being controlled by throttling.
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Ho, Serene, Valérie Pattyn, Bruno Broucker, and Joep Crompvoets. "Needs Assessment in Land Administration: The Potential of the Nominal Group Technique." Land 7, no. 3 (July 20, 2018): 87. http://dx.doi.org/10.3390/land7030087.
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This paper introduces the Nominal Group Technique (NGT) for conducting needs assessments in land administration projects. Understanding the local context of what citizens, communities and organisations need remains a complex challenge yet fundamental to the success of land administration projects. To date, key methods of understanding and identifying local needs have been qualitative in nature with various strengths and limitations. For land administration, it is also important for empirical methods to attend to power imbalances amongst participants that are a hallmark and driver of land tenure security. Although NGT has hardly been used in the domain of land administration, based on our experience of employing the method in a research project in East Africa, we argue that it presents a valuable addition to needs assessment strategies. We provide a broad outline of the method before providing a detailed description of how we employed the method. We discuss the opportunities and challenges that NGT offers, arguing that it is a time and resource efficient way of engaging communities in a participatory and equitable process which facilitates the co-production of valid and reliable knowledge on needs, and consensus on how these needs should be prioritised.
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Živanović, Dragan, Milan Simić, Zivko Kokolanski, Dragan Denić, and Vladimir Dimcev. "Generation of Long-time Complex Signals for Testing the Instruments for Detection of Voltage Quality Disturbances." Measurement Science Review 18, no. 2 (April 1, 2018): 41–51. http://dx.doi.org/10.1515/msr-2018-0007.
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Abstract Software supported procedure for generation of long-time complex test sentences, suitable for testing the instruments for detection of standard voltage quality (VQ) disturbances is presented in this paper. This solution for test signal generation includes significant improvements of computer-based signal generator presented and described in the previously published paper [1]. The generator is based on virtual instrumentation software for defining the basic signal parameters, data acquisition card NI 6343, and power amplifier for amplification of output voltage level to the nominal RMS voltage value of 230 V. Definition of basic signal parameters in LabVIEW application software is supported using Script files, which allows simple repetition of specific test signals and combination of more different test sequences in the complex composite test waveform. The basic advantage of this generator compared to the similar solutions for signal generation is the possibility for long-time test sequence generation according to predefined complex test scenarios, including various combinations of VQ disturbances defined in accordance with the European standard EN50160. Experimental verification of the presented signal generator capability is performed by testing the commercial power quality analyzer Fluke 435 Series II. In this paper are shown some characteristic complex test signals with various disturbances and logged data obtained from the tested power quality analyzer.
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Šimonová, Hana, Barbara Kucharczyková, Ivana Havlíková, Stanislav Seitl, and Zbyněk Keršner. "Complex Evaluation of Fatigue Tests Results of Plain C30/37 and C45/55 Class Concrete Specimens." Key Engineering Materials 592-593 (November 2013): 801–4. http://dx.doi.org/10.4028/www.scientific.net/kem.592-593.801.
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The aim of this paper is to summarize basic fatigue parameter values obtained for plain C30/37 and C45/55 class concrete specimens during dynamic tests. Selected approximation curves for relative mechanical-fracture parameter values over time − compressive cube strength, modulus of elasticity, effective fracture toughness and specific fracture energy − were used to determine the most accurate fatigue parameter values corresponding to the age of specimens at the time dynamic tests were performed. Three models are used for standard description of theS−Ncurve: the Weibull and Gumbel models developed by Castillo et al. as well as the power law equation. Fatigue properties were obtained from three point bending tests conducted on beam specimens (100×100×400 mm nominal size) with a central edge notch (depth 10 mm).
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Hillerstro¨m, G., and J. Sternby. "Adaptive Rejection of Periodic Disturbances With Unknown Period." Journal of Dynamic Systems, Measurement, and Control 118, no. 3 (September 1, 1996): 606–10. http://dx.doi.org/10.1115/1.2801187.
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A disturbance cancellation extension by means of Youla parametrization to a stabilizing nominal controller is investigated. In the case of a known disturbance model, disturbance frequencies or period time, it may be implemented directly as an add-on device to the existing control system. The nominal control system may be designed without consideration of the deterministic disturbances. This way it may suffice with a PID controller. It may also be a more complex one e.g., designed to obtain certain robustness properties. For known relation between the disturbance frequencies (one or more periodic signals) but unknown fundamental frequency, a frequency shaped disturbance model estimation scheme is utilized. This makes it possible to e.g., adapt the disturbance model to minimize the error directly with respect to the output. For periodic disturbances the scheme implements a self-tuning discrete time repetitive controller. To illustrate the feasibility of the approach taken it is used for rejecting a periodic disturbance acting on a nonminimum-phase plant.
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Stec, Daniel, Łukasz Krzywański, Krzysztof Zawierucha, and Łukasz Michalczyk. "Untangling systematics of the Paramacrobiotus areolatus species complex by an integrative redescription of the nominal species for the group, with multilocus phylogeny and species delineation in the genus Paramacrobiotus." Zoological Journal of the Linnean Society 188, no. 3 (January 15, 2020): 694–716. http://dx.doi.org/10.1093/zoolinnean/zlz163.
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Abstract Incomplete descriptions of nominal taxa are one of the most significant obstacles in modern taxonomy, including the taxonomy of Tardigrada. Another major problem in tardigrade systematics is the lack of tests for the reliability of genetic markers in species delineation. Here, we employ an integrative taxonomy approach to redescribe the nominal taxon for the P. areolatus complex, Paramacrobiotus areolatus. Moreover, we obtained multilocus DNA sequences for another 16 populations representing 9–12 Paramacrobiotus species collected from Europe, North America, Africa and Australia, enabling us to reconstruct the most extensive phylogeny of the genus to date. The identification of a pair of potentially cryptic dioecious P. areolatus complex species with divergent genetic distances in ITS2 (1.4%) and COI (13.8%) provided an opportunity to test the biological species concept for the first time in the history of tardigrade taxonomy. Intra- and interpopulation crosses did not differ in reproductive success in terms of F1 offspring. However, because of the low F1 family sizes, we were unfortunately unable to test F1 hybrid fertility. Although our results are only partially conclusive, they offer a baseline not only for further taxonomic and phylogenetic research on the areolatus complex, but also for studies on species delineation in tardigrades in general.
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Petkovšek, Marko, Mitja Nemec, and Peter Zajec. "Algorithm Execution Time and Accuracy of NTC Thermistor-Based Temperature Measurements in Time-Critical Applications." Mathematics 9, no. 18 (September 15, 2021): 2266. http://dx.doi.org/10.3390/math9182266.
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This paper addresses the challenges of selecting a suitable method for negative temperature coefficient (NTC) thermistor-based temperature measurement in electronic devices. Although measurement accuracy is of great importance, the temperature calculation time represents an even greater challenge since it is inherently constrained by the control algorithm executed in the microcontroller (MCU). Firstly, a simple signal conditioning circuit with the NTC thermistor is introduced, resulting in a temperature-dependent voltage UT being connected to the MCU’s analog input. Next, a simulation-based approximation of the actual temperature vs. voltage curve is derived, resulting in four temperature notations: for a look-up table principle, polynomial approximation, B equation and Steinhart–Hart equation. Within the simulation results, the expected temperature error of individual methods is calculated, whereas in the experimental part, performed on a DC/DC converter prototype, required prework and available MCU resources are evaluated. In terms of expected accuracy, the look-up table and the Steinhart–Hart equation offer superior results over the polynomial approximation and B equation, especially in the nominal temperature range of the NTC thermistor. However, in terms of required prework, the look-up table is inferior compared to the Steinhart–Hart equation, despite the latter having far more complex mathematical functions, affecting the overall MCU algorithm execution time significantly.
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Yamaguchi, Tomiharu, and Akinori Ueno. "Capacitive-Coupling Impedance Spectroscopy Using a Non-Sinusoidal Oscillator and Discrete-Time Fourier Transform: An Introductory Study." Sensors 20, no. 21 (November 9, 2020): 6392. http://dx.doi.org/10.3390/s20216392.
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In this study, we propose a new short-time impedance spectroscopy method with the following three features: (1) A frequency spectrum of complex impedance for the measured object can be obtained even when the measuring electrodes are capacitively coupled with the object and the precise capacitance of the coupling is unknown; (2) the spectrum can be obtained from only one cycle of the non-sinusoidal oscillation waveform without sweeping the oscillation frequency; and (3) a front-end measuring circuit can be built, simply and cheaply, without the need for a digital-to-analog (D-A) converter to synthesize elaborate waveforms comprising multiple frequencies. We built the measurement circuit using the proposed method and then measured the complex impedance spectra of 18 resistive elements connected in series with one of three respective capacitive couplings. With this method, each element’s resistance and each coupling’s capacitance were estimated independently and compared with their nominal values. When the coupling capacitance was set to 10 nF or 1.0 nF, estimated errors for the resistive elements in the range of 2.0–10.0 kΩ were less than 5%.
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Glaser, Sarah M., Hao Ye, Mark Maunder, Alec MacCall, Michael Fogarty, and George Sugihara. "Detecting and forecasting complex nonlinear dynamics in spatially structured catch-per-unit-effort time series for North Pacific albacore (Thunnus alalunga)." Canadian Journal of Fisheries and Aquatic Sciences 68, no. 3 (March 2011): 400–412. http://dx.doi.org/10.1139/f10-160.
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The presence of complex, nonlinear dynamics in fish populations, and uncertainty in the structure (functional form) of those dynamics, pose challenges to the accuracy of forecasts produced by traditional stock assessment models. We describe two nonlinear forecasting models that test for the hallmarks of complex behavior, avoid problems of structural uncertainty, and produce good forecasts of catch-per-unit-effort (CPUE) time series in both standardized and nominal (unprocessed) form. We analyze a spatially extensive, 40-year-long data set of annual CPUE time series of North Pacific albacore ( Thunnus alalunga ) from 1° × 1° cells from the eastern North Pacific Ocean. The use of spatially structured data in compositing techniques improves out-of-sample forecasts of CPUE and overcomes difficulties commonly encountered when using short, incomplete time series. These CPUE series display low-dimensional, nonlinear structure and significant predictability. Such characteristics have important implications for industry efficiency in terms of future planning and can inform formal stock assessments used for the management of fisheries.
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Jankowiak, Katarzyna, Marcin Naranowicz, and Karolina Rataj. "Metaphors are like lenses: Electrophysiological correlates of novel meaning processing in bilingualism." International Journal of Bilingualism 25, no. 3 (February 27, 2021): 668–86. http://dx.doi.org/10.1177/1367006921996820.
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Aims and objectives: The study provides new insights into how bilingual speakers process semantically complex novel meanings in their native (L1) and non-native language (L2). Methodology: The study employs an EEG method with a semantic decision task to novel nominal metaphors, novel similes, as well as literal and anomalous sentences presented in participants’ L1 and L2. Data and analysis: In total, 29 native speakers of Polish (L1) who were highly proficient in English (L2) took part in the study. The collected EEG signal was analyzed in terms of an event-related potential analysis. The statistical analyses were based on behavioral data (reaction times and accuracy rates) as well as mean amplitudes for the four conditions in the two languages within the N400 and LPC time windows. Findings: The results revealed the N400 effect of utterance type modulated by language nativeness, where the brainwaves for anomalous sentences, novel nominal metaphors, and novel similes converged in L2, while in L1 a graded effect was observed from anomalous sentences to novel nominal metaphors, novel similes and literal sentences. In contrast, within the late time window, a more pronounced sustained negativity to novel nominal metaphors than novel similes was observed in both languages, thus indicating that meaning integration mechanisms might be of similar automaticity in L1 and L2 when bilingual speakers are highly proficient in their L2. Altogether, the present results point to a more taxing mechanisms involved in lexico-semantic access in L2 than L1, yet such an increased effort seems to be resolved within the meaning integration phase. Originality: The findings present novel insights into how bilinguals construct new unfamiliar meanings and show how and when cognitive mechanisms engaged in this process are modulated by language nativeness. Significance: The study might provide crucial implications for further research on bilingual semantic processing as well as human creativity.
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Kaufmann, Dorit, and Juergen Rossmann. "Integration of structural simulations into a real-time capable Overall System Simulation for complex mechatronic systems." International Journal of Modeling, Simulation, and Scientific Computing 10, no. 02 (April 2019): 1940002. http://dx.doi.org/10.1142/s1793962319400026.
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To meet the rising demand of performing complex tasks in a highly technologized world, the development of mechatronic systems faces two major challenges: First, the system is integrated in a fast changing environment and has to cope with dynamically modified tasks and circumstances. At the same time, the development of new methods has to be fast, cost-effective and efficient. By taking care of both aspects simultaneously, simulations have become an acknowledged tool to cost-effectively and rapidly test and optimize new solutions for complex mechatronic systems, as they are common in, e.g., robotics. Mostly, simulation methods are specialized for one purpose and thus used as a stand-alone tool to analyze the behavior of single components or certain aspects of the whole system. But with size and complexity of the system, the susceptibility to errors rises when the interaction between components fails. If a component shows minimal deviations to its nominal behavior, huge interdependencies between components of complex systems might cause system failure. The structural behavior of a single component is therefore as crucial to the functionality of the whole system as the interplay of all components. Both aspects have to be analyzed in parallel, which is nowadays barely considered. Consequently, this work presents the integration of structural simulations into the overall picture. The developed approach consists of a concept, an implementation and the validation for an automated bidirectional interaction to integrate results from Finite Element Analysis (FEA) into an existing, real-time capable Overall System Simulation for mechatronic systems in general and robotics in particular.
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Bernhart, Gérard, F. Nazaret, and T. Cutard. "Fibre Reinforced Refractory Castables :An Alternative Solution for SPF Die Manufacturing." Materials Science Forum 551-552 (July 2007): 37–42. http://dx.doi.org/10.4028/www.scientific.net/msf.551-552.37.
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Today heat resistant cast steels are the nominal solution for Ti-SPF forming die manufacturing. Nevertheless, this materials present some drawbacks related to delivery time and cost. A fibre reinforced refractory castable (FRRC) is proposed as a new solution for prototype SPF die manufacturing. Due to the general brittleness of refractory castables, a short fibre reinforcement has been investigated in order to avoid catastrophic failure during the forming process. General macroscopic behavior of such materials is very complex and presents large evolutions with the testing temperature. The paper addresses the important benefits of the reinforcement for refractory castable in the case of loading on a complex structure. The capability of the material to support several cracks is shown in the case of a technological sample with a complex shape.
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Appelbaum, Joseph, and Tamir Maor. "Dependence of PV Module Temperature on Incident Time-Dependent Solar Spectrum." Applied Sciences 10, no. 3 (January 31, 2020): 914. http://dx.doi.org/10.3390/app10030914.
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The operating temperature of photovoltaic (PV) modules affects the photovoltaic conversion process. The operating temperature depends on various environmental conditions and on material-dependent properties of the PV modules. Many expressions for the operating temperature have been proposed in the literatures, some are simplified working Equation as NOCT (Nominal Operating Cell Temperature), and others are more complex, being based on a combination of the energy balance Equation and NOCT. The present study offers a new approach (model) for determining the PV module temperature based on the energy balance Equation and on the solar spectrum irradiance. While using the new model, the operating temperature has been determined for four module technologies: c-Si, a-Si/ μ c-Si, CdTe, and CIGS and it shows that the operating temperatures for the different cell types are close to the manufacturers’ NOCT data-sheet temperatures. For c-Si technology, for example, the simulation resulted in 43.2° and 46° for the spectrum and NOCT models, respectively. The proposed new model offers a new approach for determining the operating temperature of PV modules.
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Li, Xinye, Tao Yu, Lijuan Zhang, Hao Zeng, and Congcong Duan. "Theoretical and Numerical Analysis of Coupled Axial-Torsional Nonlinear Vibration of Drill Strings." Shock and Vibration 2021 (October 26, 2021): 1–15. http://dx.doi.org/10.1155/2021/8046635.
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Based on a lumped parameter model with two degrees of freedom, the periodic response of the coupled axial-torsional nonlinear vibration of drill strings is studied by HB-AFT (harmonic balance and alternating frequency/time domain) method and numerical simulations. The amplitude-frequency characteristic curves of axial relative displacement and torsional relative angular velocity are given to reveal the mechanism of bit bounce and stick-slip motion. The stability of periodic response is analyzed by Floquet theory, and the boundary conditions of bifurcation of periodic response are given when parameters such as nominal drilling pressure, angular velocity of turntable, and formation stiffness are varied. The results show that the amplitude of the periodic response of the system precipitates a spontaneous jump and Hopf bifurcation may occur when the angular velocity of the turntable is varied. The variation of parameters may lead to the complex dynamic behavior of the system, such as period-doubling motion, quasiperiodic motion, and chaos. Bit bounce and stick-slip phenomenon can be effectively suppressed by varying the angular velocity of turntable and nominal drilling pressure.
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Radmilovic, Nebojsa, Slavisa Stojakovic, and Goran Kvascev. "One solution of main controller in thermal power plants." Journal of Automatic Control 18, no. 1 (2008): 5–8. http://dx.doi.org/10.2298/jac0801005r.
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This paper describes functionality between pressure regulation of steam boiler and electrical power regulation of turbine-generator system at thermal power plants. Importans of this control is essentially in coordinate work mode when these complex and non-linear systems have to work as one integrated entity with tendency to produce electrical power at optimal and stable way. Steam generator - boiler is system with long transport delay and here is recommendation for improving pressure regulation. This regulation realized at thermal power plant nominal power 308MW and given working results in real time. Index Terms - boiler control, combustion control, thermal power plants, PID controller.
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Akimova, Elvira, and Tatiana Mochalova. "Representation of the Lexical and Semantic Field “Time” in the “Dictionary of Russian Dialects on the Territory of the Republic of Mordovia”." Vestnik Volgogradskogo gosudarstvennogo universiteta. Serija 2. Jazykoznanije, no. 1 (April 2019): 86–98. http://dx.doi.org/10.15688/jvolsu2.2019.1.7.
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The article deals with the specifics of the national language world picture of the Republic of Mordovia. On the basis of the lexicographic data analysis the authors note a set of language units that represent the lexical and semantic field "Time" and define its structural and semantic peculiarities. The paper shows that lexemes with time semantics are a segment of the regional dictionary. In accordance with the results of the field complex analysis, this dialectal unity of words is characterized by various meanings of time. The authors prove that the nouns nominate different intervals of time (nominations connected with religious views of rural inhabitants as well as ritual traditions are frequent). The adjectives characterize a thing or an event qualifying them depending on their relation to any time scheme. The verbs point to the actions connected with eating meals at the definite time intervals. The adverbs represent two main meanings – definite or indefinite time. The nominations of time intervals that are referred to the past demonstrate a high level of variability. The authors conclude that the lexical and semantic field "Time" demonstrates a complex lexical and semantic unity with the units that are linked into a system by basic paradigmatic relations (polysemy, synonymy, antonymy, homonymy).
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Mejia-Barron, Arturo, David Granados-Lieberman, Jose Razo-Hernandez, Juan Amezquita-Sanchez, and Martin Valtierra-Rodriguez. "Harmonic PMU Algorithm Based on Complex Filters and Instantaneous Single-Sideband Modulation." Electronics 8, no. 2 (January 29, 2019): 135. http://dx.doi.org/10.3390/electronics8020135.
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Phasor measurement units (PMUs) have become powerful monitoring tools for many applications in smart grids. In order to address the different issues related to harmonics in power systems, the fundamental phasor estimator in a PMU has been extended to the harmonic phasor estimator by several researchers around the world. Yet, the development of harmonic phasor estimators is a challenge because they have to consider time-varying frequencies since the frequency deviation in the harmonic components is proportional to the harmonic order in a dynamic way. In this work, a new algorithm for harmonic phasor estimation using an instantaneous single-sideband (SSB) modulation is presented. Unlike other SSB-based approaches, its implementation in this work is based on concepts of instantaneous phase and instantaneous frequency. In general, the proposed algorithm is divided into two stages. Firstly, the estimation of the fundamental phasor is carried out by means of a complex finite impulse response (FIR) filter which provides the analytic signal used to compute the instantaneous magnitude, phase, and frequency. Secondly, a complex FIR filter bank is proposed for the estimation of the harmonic components, where the instantaneous SSB modulation technique is applied in order to center the harmonic components into specific narrow bands for each complex filter when an off-nominal frequency occurs. The validation of the proposed algorithm is carried out by means of the current standards of phasor measurement units, i.e., Std. C37.118.1-2011 and C37.118.1a-2014, which involve steady-state, dynamic, and time performance tests.
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Tortajada, Ignacio Asensi. "Upgrade of the ATLAS Hadronic Tile Calorimeter for the High Luminosity LHC." EPJ Web of Conferences 170 (2018): 01001. http://dx.doi.org/10.1051/epjconf/201817001001.
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The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade, in 2024, will accommodate the upgrade of the detector and data acquisition system for the HL-LHC. The Tile Calorimeter (TileCal) will undergo a major replacement of its on- and off-detector electronics. In the new architecture, all signals will be digitized and then transferred directly to the off-detector electronics, where the signals will be reconstructed, stored, and sent to the first level of trigger at the rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. Changes to the electronics will also contribute to the reliability and redundancy of the system. Three different front-end options are presently being investigated for the upgrade, two of them based on ASICs, and a final solution will be chosen after extensive laboratory and test beam studies that are in progress. A hybrid demonstrator module is being developed using the new electronics while conserving compatibility with the current system. The status of the developments will be presented, including results from the several tests with particle beams.
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Lijun, Wang, and Li Qingbo. "Finite element method for solving asphalt mixture problem." International Journal of Structural Integrity 10, no. 4 (August 12, 2019): 569–79. http://dx.doi.org/10.1108/ijsi-09-2018-0052.
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Purpose Asphalt mixture is widely used in road engineering, and its performance research is particularly important. But the study of asphalt mixture performance needs a lot of tests, such as bending test, splitting test and so on. It also needs a lot of time and material resources. The purpose of this paper is to obtain test results through finite element numerical simulation, and show that this saves a lot of manpower and material resources. Design/methodology/approach The mechanical parameters of the material are obtained through uniaxial compression tests. The true stress and plastic strain are calculated according to nominal stress and nominal strain. A constitutive model is established. Then a finite element model of asphalt mixture is established. The numerical simulation and performance study of asphalt mixture bending test is carried out. At the same time, according to the above method, the asphalt mixture is subjected to freeze-thaw cycles and ultraviolet aging, and the mechanical parameters are obtained by a uniaxial compression test. A numerical model is established to simulate the bending characteristics of asphalt mixture after freeze-thaw cycles and ultraviolet aging. Findings A uniaxial compression test of the asphalt mixture is conducted to obtain nominal stress and nominal strain. The true stress and plastic strain are calculated and the elastic modulus is established with Poisson’s ratio as the elastic part, and the true stress and plastic strain as the plastic part. The model is constructed, the finite element model is established and the bending test is numerically simulated. The verified trend is consistent, and the method is feasible. According to the above method, the concrete is subjected to freeze-thaw cycle and ultraviolet aging, and the finite element model is established by using uniaxial compression test to obtain parameters. The bending test is simulated and the verification method is feasible. With the increase of the number of freeze-thaw cycles and the increase of UV aging time, the maximum bending strain of SBS modified asphalt mixture and matrix asphalt mixture is decreased .The low-temperature performance of SBS modified asphalt mixture is better than that of matrix asphalt mixture. Originality/value A method of simulating asphalt mixture test by finite element method numerical simulation is established. By using this method, the performance of asphalt mixture is studied, which saves a lot of manpower and material resources. At the same time, this method can be used to study the characteristics of asphalt mixture under complex conditions.
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Hayward, Vincent, Laeeque Daneshmend, and Ajit Nilakantan. "Trajectory generation and control for automatic manipulation." Robotica 12, no. 2 (March 1994): 115–25. http://dx.doi.org/10.1017/s0263574700016702.
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SUMMARYA method is described to convert information available at manipulator programming level into trajectories which are suitable for tracking by a servo control system. This process generates trajectories in real time which comply with general dynamic and kinematic constraints. Tracking accuracy will depend mainly on the acceleration demand of the nominal trajectory setpoints - the actuator output demands, in particular, must remain bounded. Our scheme takes into consideration at the trajectory computation level the dynamics of the underlying system, dynamically available information acquired through sensors, and various types of constraints, such as manipulators. It has been developed in the context of a multi-manipulator programming and control system called Kali and developed at McGill University.
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Hassan, Saad S. M., and Mona A. Ahmed. "New Liquid Membrane Electrode for Determination of Lidocaine in Local Anesthetic Formulations." Journal of AOAC INTERNATIONAL 69, no. 4 (July 1, 1986): 618–20. http://dx.doi.org/10.1093/jaoac/69.4.618.
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Abstract A new lidocaine-responsive liquid membrane electrode based on the use of the lidocaine reineckate ion pair complex in nitrobenzene solvent has been developed. The electrode displays a linear response for 10-2-10-5M lidocaine over the pH range of 3-6.5. The response time varies from 35 s to 1 min depending on the lidocaine concentration. The life span of the electrode is at least 1 month. Excipients and diluents commonly used in local anesthetic formulations do not interfere. Determination of lidocaine in some pharmaceutical preparations gives results with an average recovery of 99% of the nominal values and a mean standard deviation of 1.7% which compare favorably with those obtained by the U.S. Pharmacopeia method.
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Sen and Ibeas. "Parametrical Non-Complex Tests to Evaluate Partial Decentralized Linear-Output Feedback Control Stabilization Conditions from Their Centralized Stabilization Counterparts." Applied Sciences 9, no. 9 (April 26, 2019): 1739. http://dx.doi.org/10.3390/app9091739.
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. This paper formulates sufficiency-type linear-output feedback decentralized closed-loop stabilization conditions if the continuous-time linear dynamic system can be stabilized under linear output-feedback centralized stabilization. The provided tests are simple to evaluate, while they are based on the quantification of the sufficiently smallness of the parametrical error norms between the control, output, interconnection and open-loop system dynamics matrices and the corresponding control gains in the decentralized case related to the centralized counterpart. The tolerance amounts of the various parametrical matrix errors are described by the maximum allowed tolerance upper-bound of a small positive real parameter that upper-bounds the various parametrical error norms. Such a tolerance is quantified by considering the first or second powers of such a small parameter. The results are seen to be directly extendable to quantify the allowed parametrical errors that guarantee the closed-loop linear output-feedback stabilization of a current system related to its nominal counterpart. Furthermore, several simulated examples are also discussed.
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Long, Philip, Christine Chevallereau, Damien Chablat, and Alexis Girin. "An industrial security system for human-robot coexistence." Industrial Robot: An International Journal 45, no. 2 (March 19, 2018): 220–26. http://dx.doi.org/10.1108/ir-09-2017-0165.
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Purpose The installation of industrial robots requires security barriers, a costly, time-consuming exercise. Collaborative robots may offer a solution; however, these systems only comply with safety standards if operating at reduced speeds. The purpose of this paper is to describe the development and implementation of a novel security system that allows human–robot coexistence while permitting the robot to execute much of its task at nominal speed. Design/methodology/approach The security system is defined by three modes: a nominal mode, a coexistence mode and a gravity compensation mode. Mode transition is triggered by three lasers, two of which are mechanically linked to the robot. These scanners create a dynamic envelope around the robot and allow the detection of operator presence or environmental changes. To avoid velocity discontinuities between transitions, the authors propose a novel time scaling method. Findings The paper describes the system’s mechanical, software and control architecture. The system is demonstrated experimentally on a collaborative robot and is compared with the performance of a state-of-art security system. Both a qualitative and quantitative analysis of the new system is carried out. Practical implications The mode transition method is easily implemented, requires little computing power and leaves the trajectories unchanged. As velocity discontinuities are avoided, motor wear is reduced. The execution time is substantially less than a commercial alternative. These advantages can lead to economic benefits in high-volume manufacturing environments. Originality/value This paper proposes a novel system that is based on industrial material but can generate dynamic safety zones for a collaborative robot.
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RIVOALEN, ELIE, SERGE HUBERSON, and OMAR M. KNIO. "NUMERICAL STUDY OF SOUND RADIATION BY AXISYMMETRIC VORTEX RINGS." Journal of Computational Acoustics 11, no. 01 (March 2003): 11–45. http://dx.doi.org/10.1142/s0218396x03001808.
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The sound production by vortex rings is investigated by means of an axisymmetric vortex particle method. The predictions are first calibrated by analyzing the noise generated by steady vortex rings that are described by the analytical solutions of Fraenkel and Norbury. The noise produced by isolated vortex rings for both nominally steady and unsteady cores is then analyzed. For nominally steady cores, computed results indicate that the efficiency of sound radiation decreases as the slenderness parameter is reduced, and the acoustic signals reveal a dominant period that is approximately half the eddy turnover time. For unsteady cores, the amplitude of the radiated sound is substantially higher than that of similar steady rings. When the initial core vorticity distribution is nonuniform, complex internal motion may also occur within the core which is also reflected in the corresponding far-field acoustic signal. Finally, the effect of vortex stretching is analyzed based on computations of two coaxial corotating vortex rings.
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Kruse, R., and M. Steinbrecher. "Visual data analysis with computational intelligence methods." Bulletin of the Polish Academy of Sciences: Technical Sciences 58, no. 3 (September 1, 2010): 393–401. http://dx.doi.org/10.2478/v10175-010-0037-z.
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Visual data analysis with computational intelligence methodsVisual data analysis is an appealing and increasing field of application. We present two related visual analysis approaches that allow for the visualization of graphical model parameters and time-dependent association rules. When the graphical model is defined over purely nominal attributes, its local structure can be interpreted as an association rule. Such association rules comprise one of the most prominent and wide-spread analysis techniques for pattern detection, however, there are only few visualization methods. We introduce an alternative visual representation that also incorporates time since patterns are likely to change over time when the underlying data was collected from real-world processes. We apply the technique to both an artificial and a complex real-life dataset and show that the combined automatic and visual approach gives more and faster insight into the data than a fully-automatic approach only. Thus, our proposed method is capable of reducing considerably the analysis time.
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Panov, Evgenyi N., and Larissa Yu Zykova. "Differentiation and Interrelations of Two Representatives of Laudakia stellio Complex (Reptilia: Agamidae) in Israel." Russian Journal of Herpetology 4, no. 2 (October 15, 2011): 102–14. http://dx.doi.org/10.30906/1026-2296-1997-4-2-102-114.
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Field studies were conducted in Central Negev within the breeding range of Laudakia stellio brachydactyla and in NE Israel (Qyriat Shemona) in the range of an unnamed form (tentatively “Near-East Rock Agama”), during March – May 1996. Additional data have been collected in Jerusalem at a distance of ca. 110 km from the first and about 170 km from the second study sites. A total of 63 individuals were caught and examined. The animals were marked and their subsequent movements were followed. Social and signal behavior of both forms were described and compared. Lizards from Negev and Qyriat Shemona differ from each other sharply in external morphology, habitat preference, population structure, and behavior. The differences obviously exceed the subspecies level. At the same time, the lizards from Jerusalem tend to be intermediate morphologically between those from both above-named localities, which permits admitting the existence of a limited gene flow between lizard populations of Negev and northern Israel. The lizards from NE Israel apparently do not belong to the nominate subspecies of L. stellio and should be regarded as one more subspecies within the species.
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Baechler, Raffaela. "Diachronic complexification and isolation." Yearbook of the Poznan Linguistic Meeting 1, no. 1 (December 1, 2014): 1–28. http://dx.doi.org/10.1515/yplm-2015-0001.
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Abstract One may hear that over time languages tend to simplify their grammar and notably their morphological system. This intuition, probably based on linguists’ knowledge of the rich inflectional systems of older Indo-European languages, has been challenged, particularly by sociolinguistic typologists (e.g. Trudgill 2011; Braunmuller 1984, 2003; Nichols 1992). They hypothesise that languages spoken by small and isolated communities with a dense network may complexify their grammar (Trudgill 2011: 146-147). The present article investigates the nominal inflection systems of 14 varieties of German in order to survey whether there is any such diachronic tendency towards simplification and whether instances of complexification can be observed, too. The varieties under analysis include present-day Standard German, Old High German and Middle High German (two older stages of German) and eleven present-day non-standard varieties which make part of the Alemannic dialect group. First, it will be shown that there is a diachronic tendency towards simplification if we consider the total complexity of nominal inflection. Second, however, we can identify instances of diachronic complexification too if we take a closer look at single categories. Interestingly, diachronic complexification appears only in the non-standard varieties, not so in the standard variety. This may support the hypothesis that isolated varieties are more complex than non-isolated ones.
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RICE, STANLEY A., and KATHERINE A. RICE. "Variable modes of larval development in the Polydora cornuta complex (Polychaeta: Spionidae) are directly related to stored sperm availability." Zoosymposia 2, no. 1 (August 31, 2009): 397–414. http://dx.doi.org/10.11646/zoosymposia.2.1.28.
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Reproductive crosses between geographically separated populations of the nominal species, Polydora cornuta, support the hypothesis that the Florida/ Gulf of Mexico populations represent a single, potentially interbreeding lineage that is reproductively isolated from West Coast (California) and East Coast (Carolinas to Maine) populations. Previous research has indicated that California populations are reproductively compatible with worms from North Carolina but reproductively isolated from Maine populations. In spite of these species-level differences, all populations of this nominal species deposit egg capsules inside the female’s tube that usually develop into three-chaetiger planktonic larvae measuring about 200 µm in length. Although adelphophagy (feeding upon unfertilized eggs within an egg capsule) has been reported in some populations of P. cornuta and in numerous other spionid polychaetes, the relationship between stored sperm in the female parent and the size of larvae within capsules has not been explored. We raised isolated female P. cornuta from three genetically and reproductively distinct populations (Florida, California and Maine) over a period of about 16 weeks and determined percent fertilization and larval size in successive spawnings over time until the females ran out of stored sperm. As each female used up stored sperm during successive spawnings, the percent of fertilized eggs per capsule declined and larval size at release increased. In some cases, the largest larvae produced by an isolated female were 114% larger than the smallest larvae produced by the same female. Larvae inside capsules containing unfertilized eggs fed upon these eggs and grew larger than larvae that did not have unfertilized eggs to feed upon. The effects of producing larger larvae following stored sperm depletion were completely reversed by transfer of fresh spermatophores to the isolated females. Variable larval size produced by a single female worm (poecilogony) may therefore be a result of stored sperm limitations rather than a genetically determined reproductive strategy in this species complex.
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Farihi, J., J. J. Hermes, T. R. Marsh, A. J. Mustill, M. C. Wyatt, J. A. Guidry, T. G. Wilson, et al. "Relentless and complex transits from a planetesimal debris disc." Monthly Notices of the Royal Astronomical Society 511, no. 2 (February 8, 2022): 1647–66. http://dx.doi.org/10.1093/mnras/stab3475.
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ABSTRACT This article reports quasi-continuous transiting events towards WD 1054–226 at d = 36.2 pc and V = 16.0 mag, based on simultaneous, high-cadence, multiwavelength imaging photometry using ULTRACAM over 18 nights from 2019 to 2020 March. The predominant period is 25.02 h and corresponds to a circular orbit with blackbody Teq = 323 K, where a planetary surface can nominally support liquid water. The light curves reveal remarkable night-to-night similarity, with changes on longer time-scales, and lack any transit-free segments of unocculted starlight. The most pronounced dimming components occur every 23.1 min – exactly the 65th harmonic of the fundamental period – with depths of up to several per cent, and no evident colour dependence. Myriad additional harmonics are present, as well as at least two transiting features with independent periods. High-resolution optical spectra are consistent with stable, photospheric absorption by multiple, refractory metal species, with no indication of circumstellar gas. Spitzer observations demonstrate a lack of detectable dust emission, suggesting that the otherwise hidden circumstellar disc orbiting WD 1054–226 may be typical of polluted white dwarfs, and detected only via favourable geometry. Future observations are required to constrain the orbital eccentricity, but even if periastron is near the Roche limit, sublimation cannot drive mass loss in refractory parent bodies, and collisional disintegration is necessary for dust production.
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Dolzhenko, N. G. "Temporal semantics of sentences with a deverbative turn (based on the works by E. D. Aypin)." Bulletin of Ugric studies 11, no. 3 (2021): 427–34. http://dx.doi.org/10.30624/2220-4156-2021-11-3-427-434.
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hich is one of the important structural and semantic indicators of any syntactic construction. Objective: to describe the grammatical meaning of the temporality of simple polypropositive sentences that include verbal nominal grammems, as well as a turn with these grammems and dependent word forms (deverbative turns); to identify the features of the time of these sentences. Research materials: simple sentences with deverbative turns, extracted from two essays by E. D. Aypin, in which time plays the most important meaning, organizing and functional-stylistic roles within the entire text. Results and novelty of the research: the result of the study is the representation of a complex, multidimensional picture of time in the designated structures. Against the background of the absolute meaning of the past tense, various forms of the relative tense of the verbal noun and constructions, in which these names are the main components, are identified. The article describes the taxis and deixis of simple polypropositive sentences, the synchronous and asynchronous time perspective expressed in sentences by formal, lexical means, as well as by the logic of represented events. The novelty of the research is both the material itself (sentences with deverbative turns used in certain literary texts), and the identification of a complex composition of a time perspective, a specific time relationship of two events, two situations within a simple sentence.
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Ning, Shungang, Jianzhong Sun, Cui Liu, and Yang Yi. "Applications of deep learning in big data analytics for aircraft complex system anomaly detection." Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability 235, no. 5 (March 14, 2021): 923–40. http://dx.doi.org/10.1177/1748006x211001979.
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Big data analytics with deep learning approach have attracted increasing attention in transportation engineering, involving operations, maintenance, and safety. In commercial aviation sectors, operational, and maintenance data produced on modern aircraft is increasing exponentially, and predictive analysis of these data is an exciting and promising field in aviation maintenance, which has a potential to revolutionize aerospace maintenance industry. This study illustrates the state-of-the-art applications of deep learning in big data analytics for predictive maintenance and a real-world case study for commercial aircraft. A Long Short-Term Memory network based Auto-Encoders (LSTM-AE) is proposed for complex aircraft system fault detection and classification, which makes use of the raw time-series data from heterogeneous sensors. The proposed method uses nominal time-series samples corresponding to healthy behavior of the system to learn a reconstruction model based on LSTM-AE framework. Then the system health index (HI) and fault feature vectors are derived from the reconstruction error matrix for fault detection and classification. The proposed method is demonstrated on a real-world data set from a commercial aircraft fleet. The typical PCV faults as well as the 390 F sensor and 450 F sensor faults due to sense line air leakage are successfully detected and distinguished based on the extracted features. The case study results show that the computed HI can effectively characterize the health state of the aircraft system and different fault types can be identified with high confidence, which is helpful for line fault troubleshooting.
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Hashlamoun, Taha M., Sergey B. Vygovsky, Sergey T. Leskin, and A. Safa Duman. "Determination of 18-month fuel cycle parameters for the purpose of fuel costs minimization at the basis of use constructions of fuel assemblies in VVER-1200 reactors." Nuclear Energy and Technology 5, no. 1 (March 20, 2019): 9–15. http://dx.doi.org/10.3897/nucet.5.33976.
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This article presents the results of research, that were focused on determining the optimal parameters of the extension of (reactor life-time) reactor fuel cycle in order to reduce the total operating costs of nuclear power plants during the transition from 12-month reactor fuel cycle to 18-month fuel cycle. The relevance of the research is related to the fact that, in recent years, there is a transition at all operating nuclear power plants VVER-1000 (1200) from 12-month reactor fuel cycle to extended 18-month fuel cycle. At the same time, represent the interests to solve the problem of conservation the extension of reactor life-time while reducing the number of loaded fuel assemblies with fresh fuel assemblies, which would reduce the total operating, and fuel costs. Search for solutions of this problem is associated with mandatory implementation of all requirements for the safe operation of the reactor and the reduction of the maximum fast neutron fluence on the reactor vessel in comparison with its value at the operating nuclear power plants. In the present work, with using the program PROSTOR software complex researched the neutron-physical characteristics of the core at the nominal parameters of the VVER-1200 reactor through the implementation of various fuel cycle strategies. The article developed various schemes of fuel-reloading for an 18-month fuel cycle with a different number of fuel assemblies. The article carries out a comparative analysis of the main parameters in the core for fuel-reloading schemes options of an 18- and 12-month fuel cycle with each other. Determine the minimum amount of fuel assemblies and provide the necessary duration of the reactor life-time for 18-month fuel cycle with using the extension of reactor life-time by reducing the power at the end of the reactor cycle to 70% of the nominal power. In the article, the arrangements of fuel assemblies were developed to provide limitations of local power by volume of the core, which reduce the fluence of fast neutrons on the reactor vessel in comparison with the projected value of the fluence. This article shows that the 18-month fuel cycle for the VVER-1200 reactor is more economical than the 12-month fuel cycle. These studies were carried out for the VVER-1200 reactor at the power of 100% of the nominal.
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Terry, W. Scott. "Everyday Forgetting: Data from a Diary Study." Psychological Reports 62, no. 1 (February 1988): 299–303. http://dx.doi.org/10.2466/pr0.1988.62.1.299.
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50 subjects were asked to keep a diary of instances in which they realized they had forgotten something. The 750 forgettings recorded were grouped on the basis of nominal similarity, with 64% of them falling into one of 24 categories. The major categories included forgetting to comply with requests, failures of habitual actions, absentmindedness, and forgetting to bring something. Most failures involved the forgetting to perform a future action (i.e., forgetting to do something) as opposed to forgetting facts, names, or other information once known. These results suggest that the failure to retrieve the intention to do something at the appropriate time is the source of many forgettings, and this finding may have implications for the construction of memory inventories.
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Kim, M.-H., and S.-W. Kang. "Testing and analysis of fatigue behaviour in edge details: A comparative study using hot spot and structural stresses." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, no. 12 (December 1, 2008): 2351–63. http://dx.doi.org/10.1243/09544062jmes999.
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At present, the fatigue design of welded structures is primarily based on a nominal stress or hot spot stress (HSS) approach with a series of classified weld S-N curves. Although well accepted by major industries, the nominal stress-based fatigue design approach is relatively cumbersome in terms of securing a series of S-N curves corresponding to each class of joint types and loading modes. Moreover, it is very difficult, if not impossible, to determine the nominal stress at each structural component, particularly in complex ship structures. The HSS-based fatigue design is based on the stress at the weld toes obtained by linear or quadratic extrapolation of stresses over two or three points in front of the weld toe. Finite-element analysis is mostly applied. However, this method has a difficulty of finding a proper stress through the global model, the medium size model and the detail model of ship structure. Besides, the calculated HSS values may vary depending on the extrapolation technique used. Recently, a mesh-size insensitive structural stress (SS) definition that gives a stress state at the weld toe with a relatively large mesh size has been proposed. The SS definition is based on the elementary structural mechanics theory and provides an effective measure of a stress state in front of the weld toe. As an experimental validation of the Battelle SS method in obtaining the fatigue strength of weldments, a series of experiments are carried out for various sizes of weldments. Based on the results from this study, it is expected to achieve the development of a more precise fatigue strength evaluation technique and saving on the time required in the fatigue design of ship and offshore structures.
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Puchkov, A. F., V. F. Kablov, M. P. Spiridonova, N. A. Tret'yakova, O. A. Vysochinskaya, and E. I. Gerasimenko. "The Possibility of using Complex Anti-Agers for Rubber Compounds Based on Polyisoprene Rubbers and Operating under Extreme Conditions." International Polymer Science and Technology 45, no. 4 (April 2018): 147–51. http://dx.doi.org/10.1177/0307174x1804500403.
Full textAbstract:
The effect of complex anti-agers on the behaviour under extreme conditions of rubber compounds based on SKI-3 isoprene rubber was studied. Data for rubber compounds containing only N-isopropyl-N-phenyl-p-phenylenediamine (IPPD) or a complex salt that besides IPPD contains ∊-caprolactam (PRS-1N) were compared. The nominal tensile strength, ft, and dynamic strength, N, were determined on an MRS-2 machine, the abrasive wear, α, on a Grasselli machine, and the amount of sol fraction (SF) on a viscometer, and the equilibrium degree of swelling in toluene, Qequ, was also determined. IR spectra were obtained using a Nicolet-6700 Fourier IR spectrometer, and electron micrographs using an EM-14 microscope. Heat treatment of the rubber compounds under critical (for isoprene rubbers) temperature conditions (at 140°C) for different periods of time, τ, makes it possible to increase N considerably, and to reduce α. The values of N are practically the same for rubber compounds with IPPD and PRS-1N, and the maximum is achieved at τ = 25 h. The values of α are considerably lower for rubber compounds containing PRS-1N. The results with respect to SF, Qequ, IR spectroscopy, and electron microscopy confirm the presence of a certain temperature-time zone in which physicochemical processes postponing catastrophic failure of the rubber compound occur. The use of complex anti-agers with synergy in their protective action enables the time before catastrophic failure of an article to be increased.
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Anand, Shin, Saxena, and Memon. "Accelerated Reliability Growth Test for Magnetic Resonance Imaging System Using Time-of-Flight Three-Dimensional Pulse Sequence." Diagnostics 9, no. 4 (October 25, 2019): 164. http://dx.doi.org/10.3390/diagnostics9040164.
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A magnetic resonance imaging (MRI) system is a complex, high cost, and long-life product. It is a widely known fact that performing a system reliability test of a MRI system during the development phase is a challenging task. The major challenges include sample size, high test cost, and long test duration. This paper introduces a novel approach to perform a MRI system reliability test in a reasonably acceptable time with one sample size. Our approach is based on an accelerated reliability growth test, which consists of test cycle made of a very high-energy time-of-flight three-dimensional (TOF3D) pulse sequence representing an actual hospital usage scenario. First, we construct a nominal day usage scenario based on actual data collected from an MRI system used inside the hospital. Then, we calculate the life-time stress based on a usage scenario. Finally, we develop an accelerated reliability growth test cycle based on a TOF3D pulse sequence that exerts highest vibration energy on the gradient coil and MRI system. We use a vibration energy model to map the life-time stress and reduce the test duration from 537 to 55 days. We use a Crow AMSAA plot to demonstrate that system design reaches its useful life after crossing the infant mortality phase.
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Zhunusova, M. K., and A. Zh Sayazhanova. "The syntactic structure of the initial and final sentences." Bulletin of the Karaganda University. Philology series 99, no. 3 (September 30, 2020): 65–72. http://dx.doi.org/10.31489/2020ph3/65-72.
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The article analyzes the key role of syntactic features in the composition of the text. It was determined that the first and last sentences of the text are syntactically diverse. Sentence words, simple, introductory, and complex sentences perform communicative, expressive, and stylistic functions in the text. The semantic and compressed structures, modality, expressiveness, and stylistic skills that are based on various structures of these sentences were studied to reveal the clarity and comprehensibility of the idea of sentences. It is emphasized that with the help of syntactic laws, by means of one-or two-part sentences that convey the idea of the text, the features of the character are briefly and concisely revealed. The features of the formation of various initial sentences are defined. The syntactic structure of initial and final sentences is different: simple, ambiguous, complete, incomplete, positive, negative. All types of single-part components are nominal, vocative, and non-articulate sentences. However, such sentences are not complex, they are mostly simple short sentences. Semantic and syntactic characteristics of initial and final sentences are described in their idiomatic, narrative, interrogative, and complex forms. It was determined by the semantic properties of rhetorical questions in the initial proposals. It should be noted that the nominal structure of the initial sentences of the text is used not only for ease of description but also for emotionality as if it is related to certain aspects of the plot or the general content of the story and affects the reader's feelings. It is believed that the authors in the initial sentences not only indicate the time or place of the event, but also describe human behavior in relation to the environment and nature, and thus allow the reader to predict the end of the story. It was ascertained that the initial and final sentences, depending on the historical period, can be used in both positive and negative meanings.
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Mayorga-Macías, Walter Alejandro, Luis Enrique González-Jiménez, Marco Antonio Meza-Aguilar, and Luis Fernando Luque-Vega. "Velocity Sensor for Real-Time Backstepping Control of a Multirotor Considering Actuator Dynamics." Sensors 20, no. 15 (July 29, 2020): 4229. http://dx.doi.org/10.3390/s20154229.
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A real-time implementation of a control scheme for a multirotor, based on angular velocity sensors for the actuators, is presented. The control scheme is composed of two loops: an inner loop for the actuators and an outer loop for the unmanned aerial vehicle (UAV). The UAV control algorithm is designed by means of the backstepping technique and a robust sliding mode differentiator, and the actuator control strategy is based on a standard proportional-integral-derivative (PID) controller. A robust exact differentiator, based on high order sliding modes, is used to estimate the complex derivatives present in the proposed control law. As the measurements of the propeller’s angular velocities are required for the control law, velocity sensors are mounted in the axles of the rotors to retrieve them and a signal conditioning stage is implemented. In addition, dynamical models for the actuators of the aircraft were calculated by means of transfer functions obtained via experimental measurements in a test bench developed for this purpose. This test bench permits to characterize the parameters of the transfer functions by comparing the forces computed using the nominal parameter to the measured forces. To this end, it is assumed that the loads in the actuators of the vehicle are insignificant during flight. The effectiveness of the proposed sensor, its signal conditioning, and the overall control scheme are validated by means of simulation results and real-time experiments.
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Danışman, Can Burak, Filiz Şahin, Onuralp Yücel, and Gültekin Göller. "Microstructural Investigation of TZM Alloys processed by Spark Plasma Sintering." MRS Advances 1, no. 17 (December 28, 2015): 1183–90. http://dx.doi.org/10.1557/adv.2015.44.
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ABSTRACTMolybdenum based alloy having a nominal composition Mo–0.5Ti–0.1Zr–0.02C (wt%) popularly known as TZM alloy possess high temperature strength, high creep resistance, low coefficient of thermal expansion and high thermal conductivity. Processed TZM alloy contains TiC, ZrC and complex carbides which inhibit recrystallization at high temperatures and also improve the working conditions. In this study, the effect of sintering temperature, holding time and pressure on densification, microstructure and hardness of the spark plasma sintered TZM alloys were investigated. The sample sintered at 1575 °C for 150 second under 40 MPa exhibited the highest relative density, ∼98%. Microstructural characterization was performed by using FESEM and it was observed that TiC and ZrC dispersed through the microstructure. The average size of precipitates were measured as 7.5 and 3.5 µm for TiC and ZrC, respectively.