Journal articles on the topic 'Envelope function model'
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Zhang, X., C. E. Lee, and X. Shao. "Envelopes in multivariate regression models with nonlinearity and heteroscedasticity." Biometrika 107, no. 4 (June 17, 2020): 965–81. http://dx.doi.org/10.1093/biomet/asaa036.
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Summary Envelopes have been proposed in recent years as a nascent methodology for sufficient dimension reduction and efficient parameter estimation in multivariate linear models. We extend the classical definition of envelopes in Cook et al. (2010) to incorporate a nonlinear conditional mean function and a heteroscedastic error. Given any two random vectors ${X}\in\mathbb{R}^{p}$ and ${Y}\in\mathbb{R}^{r}$, we propose two new model-free envelopes, called the martingale difference divergence envelope and the central mean envelope, and study their relationships to the standard envelope in the context of response reduction in multivariate linear models. The martingale difference divergence envelope effectively captures the nonlinearity in the conditional mean without imposing any parametric structure or requiring any tuning in estimation. Heteroscedasticity, or nonconstant conditional covariance of ${Y}\mid{X}$, is further detected by the central mean envelope based on a slicing scheme for the data. We reveal the nested structure of different envelopes: (i) the central mean envelope contains the martingale difference divergence envelope, with equality when ${Y}\mid{X}$ has a constant conditional covariance; and (ii) the martingale difference divergence envelope contains the standard envelope, with equality when ${Y}\mid{X}$ has a linear conditional mean. We develop an estimation procedure that first obtains the martingale difference divergence envelope and then estimates the additional envelope components in the central mean envelope. We establish consistency in envelope estimation of the martingale difference divergence envelope and central mean envelope without stringent model assumptions. Simulations and real-data analysis demonstrate the advantages of the martingale difference divergence envelope and the central mean envelope over the standard envelope in dimension reduction.
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Zhang, Lei Yu, Rui Hua Zhuo, Li Jian Liu, and Shu Zhong Feng. "A Piecewise Function Smooth Strength Envelope Model." Applied Mechanics and Materials 182-183 (June 2012): 1069–73. http://dx.doi.org/10.4028/www.scientific.net/amm.182-183.1069.
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The method of trigonometric series is one of widely used methods for calculating artificial ground motion. But using this method the speed of time, it was found that the zero line must exist the phenomenon of drift. This text fore person the foundation of the research up, a kind of more perfect model of differentiable nonsingular strength envelope function is proposed .a better resolve this problem. Passing the calculation proved that the new method is reasonable and effective.
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Rodríguez-Coppola, H., J. L. Martínez-Cuellar, and R. Pérez-Álvarez. "Two-Band Envelope Function Model for Graded Interfaces." physica status solidi (b) 158, no. 2 (April 1, 1990): 481–91. http://dx.doi.org/10.1002/pssb.2221580209.
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Dargahi-Noubary, G. R. "An envelope function model for forecasting athletics records." Journal of Forecasting 13, no. 1 (January 1994): 11–20. http://dx.doi.org/10.1002/for.3980130103.
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Strzałka, Radosław, Łukasz Chuchra, and Janusz Wolny. "Envelope Function Analysis of Quasicrystals." Crystals 12, no. 4 (April 11, 2022): 536. http://dx.doi.org/10.3390/cryst12040536.
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Quasicrystals have attracted a growing interest in material science because of their unique properties and applications. Proper determination of the atomic structure is important in designing a useful application of these materials, for which a difficult phase problem of the structure factor must be solved. Diffraction patterns of quasicrystals consist of a periodic series of peaks, which can be reduced to a single envelope. Knowing the distribution of the diffraction image into series, it is possible to recover information about the phase of the structure factor without using time-consuming iterative methods. By the inverse Fourier transform, the structure factor can be obtained (enclosed in the shape of the average unit cell, or atomic surface) directly from the diffraction patterns. The method based on envelope function analysis was discussed in detail for a model 1D (Fibonacci chain) and 2D (Penrose tiling) quasicrystal. First attempts to apply this technique to a real Al-Cu-Rh decagonal quasicrystal were also made.
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Vencovský, Václav. "Roughness Prediction Based on a Model of Cochlear Hydrodynamics." Archives of Acoustics 41, no. 2 (June 1, 2016): 189–201. http://dx.doi.org/10.1515/aoa-2016-0019.
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Abstract The term roughness is used to describe a specific sound sensation which may occur when listening to stimuli with more than one spectral component within the same critical band. It is believed that the spectral components interact inside the cochlea, which leads to fluctuations in the neural signal and, in turn, to a sensation of roughness. This study presents a roughness model composed of two successive stages: peripheral and central. The peripheral stage models the function of the peripheral ear. The central stage predicts roughness from the temporal envelope of the signal processed by the peripheral stage. The roughness model was shown to account for the perceived roughness of various types of acoustic stimuli, including the stimuli with temporal envelopes that are not sinusoidal. It thus accounted for effects of the phase and the shape of the temporal envelope on roughness. The model performance was poor for unmodulated bandpass noise stimuli.
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Wu, Ru-Shan, Jingrui Luo, and Bangyu Wu. "Seismic envelope inversion and modulation signal model." GEOPHYSICS 79, no. 3 (May 1, 2014): WA13—WA24. http://dx.doi.org/10.1190/geo2013-0294.1.
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We recognized that the envelope fluctuation and decay of seismic records carries ultra low-frequency (ULF, i.e., the frequency below the lowest frequency in the source spectrum) signals that can be used to estimate the long-wavelength velocity structure. We then developed envelope inversion for the recovery of low-wavenumber components of media (smooth background), so that the initial model dependence of waveform inversion can be reduced. We derived the misfit function and the corresponding gradient operator for envelope inversion. To understand the long-wavelength recovery by the envelope inversion, we developed a nonlinear seismic signal model, the modulation signal model, as the basis for retrieving the ULF data and studied the nonlinear scale separation by the envelope operator. To separate the envelope data from the wavefield data (envelope extraction), a demodulation operator (envelope operator) was applied to the waveform data. Numerical tests using synthetic data for the Marmousi model proved the validity and feasibility of the proposed approach. The final results of combined [Formula: see text] (envelope-inversion for smooth background plus waveform-inversion for high-resolution velocity structure) indicated that it can deliver much improved results compared with regular full-waveform inversion (FWI) alone. Furthermore, to test the independence of the envelope to the source frequency band, we used a low-cut source wavelet (cut from 5 Hz below) to generate the synthetic data. The envelope inversion and the combined [Formula: see text] showed no appreciable difference from the full-band source results. The proposed envelope inversion is also an efficient method with very little extra work compared with conventional FWI.
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Albin, Nathan, Sergio Conti, and Georg Dolzmann. "Infinite-order laminates in a model in crystal plasticity." Proceedings of the Royal Society of Edinburgh: Section A Mathematics 139, no. 4 (July 8, 2009): 685–708. http://dx.doi.org/10.1017/s0308210508000127.
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We consider a geometrically nonlinear model for crystal plasticity in two dimensions, with two active slip systems and rigid elasticity. We prove that the rank-1 convex envelope of the condensed energy density is obtained by infinite-order laminates, and express it explicitly via the 2F1 hypergeometric function. We also determine the polyconvex envelope, leading to upper and lower bounds on the quasiconvex envelope. The two bounds differ by less than 2%.
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Nirmal, Jagannath, Suprava Patnaik, Mukesh Zaveri, and Pramod Kachare. "Complex Cepstrum Based Voice Conversion Using Radial Basis Function." ISRN Signal Processing 2014 (February 6, 2014): 1–13. http://dx.doi.org/10.1155/2014/357048.
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The complex cepstrum vocoder is used to modify the speaker specific characteristics of the source speaker speech to that of the target speaker speech. The low time and high time liftering are used to split the calculated cepstrum into the vocal tract and the source excitation parameters. The obtained mixed phase vocal tract and source excitation parameters with finite impulse response preserve the phase properties of the resynthesized speech frame. The radial basis function is explored to capture the nonlinear mapping function for modifying the complex cepstrum based real and imaginary components of the vocal tract and source excitation of the speech signal. The state-of-the-art Mel cepstrum envelope and the fundamental frequency (F0) are considered to represent the vocal tract and the source excitation of the speech frame, respectively. Radial basis function is used to capture and formulate the nonlinear relations between the Mel cepstrum envelope of the source and target speakers. Mean and standard deviation approach is employed to modify the fundamental frequency (F0). The Mel log spectral approximation filter is used to reconstruct the speech signal from the modified Mel cepstrum envelope and fundamental frequency. A comparison of the proposed complex cepstrum based model has been made with the state-of-the-art Mel Cepstrum Envelope based voice conversion model with objective and subjective evaluations. The evaluation measures reveal that the proposed complex cepstrum based voice conversion system approximate the converted speech signal with better accuracy than the model based on the Mel cepstrum envelope based voice conversion.
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Qu, Zhipeng, Wei He, Mingyun Lv, and Houdi Xiao. "Large-Strain Hyperelastic Constitutive Model of Envelope Material under Biaxial Tension with Different Stress Ratios." Materials 11, no. 9 (September 19, 2018): 1780. http://dx.doi.org/10.3390/ma11091780.
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This paper reports the biaxial tensile mechanical properties of the envelope material through experimental and constitutive models. First, the biaxial tensile failure tests of the envelope material with different stress ratio in warp and weft directions are carried out. Then, based on fiber-reinforced continuum mechanics theory, an anisotropic hyperelastic constitutive model on envelope material with different stress ratio is developed. A strain energy function that characterizes the anisotropic behavior of the envelope material is decomposed into three parts: fiber, matrix and fiber–fiber interaction. The fiber–matrix interaction is eliminated in this model. A new simple model for fiber–fiber interaction with different stress ratio is developed. Finally, the results show that the constitutive model has a good agreement with the experiment results. The results can be used to provide a reference for structural design of envelope material.
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Cunningham, Thomas, R. C. Barker, and L. C. Chiu. "A comparison using a delta‐function model of envelope function approximations for quantum wells." Journal of Applied Physics 63, no. 11 (June 1988): 5393–97. http://dx.doi.org/10.1063/1.340357.
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Morandi, O., and L. Demeio. "A Wigner-Function Approach to Interband Transitions Based on the Multiband-Envelope-Function Model." Transport Theory and Statistical Physics 37, no. 5-7 (December 18, 2008): 437–59. http://dx.doi.org/10.1080/00411450802536607.
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Borisov, Dmitry, Ryan Modrak, Fuchun Gao, and Jeroen Tromp. "3D elastic full-waveform inversion of surface waves in the presence of irregular topography using an envelope-based misfit function." GEOPHYSICS 83, no. 1 (January 1, 2018): R1—R11. http://dx.doi.org/10.1190/geo2017-0081.1.
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Full-waveform inversion (FWI) is a powerful method for estimating the earth’s material properties. We demonstrate that surface-wave-driven FWI is well-suited to recovering near-surface structures and effective at providing S-wave speed starting models for use in conventional body-wave FWI. Using a synthetic example based on the SEG Advanced Modeling phase II foothills model, we started with an envelope-based objective function to invert for shallow large-scale heterogeneities. Then we used a waveform-difference objective function to obtain a higher-resolution model. To accurately model surface waves in the presence of complex tomography, we used a spectral-element wave-propagation solver. Envelope misfit functions are found to be effective at minimizing cycle-skipping issues in surface-wave inversions, and surface waves themselves are found to be useful for constraining complex near-surface features.
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Sobey, Rodney J., and Han-Bin Liang. "COMPLEX ENVELOPE IDENTIFICATION OF WAVE GROUPS." Coastal Engineering Proceedings 1, no. 20 (January 29, 1986): 57. http://dx.doi.org/10.9753/icce.v20.57.
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The complex envelope function is presented as the natural analysis technique for wave records where the identification of wave groups is a dominant interest. Algorithms have been developed and confirmed for separation of the complex envelope function, estimation of the dominant frequency and unwrapping of the phase function. Cross-correlograms and coherence spectra reveal a link between the envelope amplitude and phase traces that appears to be an intrinsic property of wave groups. Nevertheless, the majority of the information in typical wave records can be described as random, accounting for the relative success of the Gaussian random wave model.
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Shao, Heng, Zhigeng Fang, Qin Zhang, Qian Hu, Jiajia Cai, and Liangyan Tao. "Research on an exponential distribution reliability function model based on multi-source heterogeneous data supplements." Grey Systems: Theory and Application 7, no. 3 (November 6, 2017): 329–42. http://dx.doi.org/10.1108/gs-06-2017-0017.
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Purpose As productions show characteristics of multi-varieties and small batch in a recent new product system, it is more difficult to acquire its failure rate data. With the help of expert experience information, the authors can get the interval estimation of failure rate data under different methods, so how to make the interval convergence with the new information is an important problem to be solved. The paper aims to discuss this issue. Design/methodology/approach In this paper, the concept of generalized standard grey number is used to characterize the multi-source heterogeneous uncertainty failure rate data into a unified framework. Then, the engineering construction method is used to calculate the average failure rate and build the grey exponential distribution reliability function, whose image is presented as the possible region of the two-curve envelope. Findings Further, according to the normal distribution assumption of the regional convergence based on the information supplement, the convergence problem of the reliability function is transformed into the convergence of the area of the curve envelope region, and construct the multi-objective programming model with the minimum envelope area and the lowest total cost of information acquisition, acquire the conclusion that the failure rate is equal to the nuclear of the average failure rate when the envelope region converges. Originality/value Through the case analysis of the equipment ejection system of the Harbinger system, five groups of results are obtained by Matlab simulation, which verify the rationality and feasibility of the model described in this paper.
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Dantas, Renato R. S., Walter E. Medeiros, and Jessé C. Costa. "A multiscale approach to full-waveform inversion using a sequence of time-domain misfit functions." GEOPHYSICS 84, no. 4 (July 1, 2019): R539—R551. http://dx.doi.org/10.1190/geo2018-0291.1.
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Most of the approaches designed to avoid cycle skipping in full-waveform inversion (FWI) involve calculating a sequence of inversions in a multiscale fashion. We have adopted an alternative strategy, which is inverting a sequence of different misfit functions in the time domain. This is an implicit multiscale approach in the sense that the used misfit functions are sensitive to different wavelengths, but all of the inversion steps use the same modeling algorithm and the same model grid. In the first and third inversion steps, the transmitted (early arrivals) and reflected (late arrivals) components of the wavefield envelopes are respectively fitted. The second step promotes a smooth transition between the first and third steps, by using the envelope of the complete waveform. Because fitting just the envelope of the reflected waves has a minor effect on the misfit function of the whole data set, the phases of the reflected waves are mostly fitted in the fourth step, which is based on the waveform misfit function preserving only the late arrivals. The third and fourth steps are of crucial importance to fit the reflected events. We test the sequential inversion approach with the Marmousi model using data sets with different frequencies, obtaining better estimates of the velocity field than those obtained with the classic FWI. The solutions obtained with classic FWI and sequential inversion approach degrade with a progressively higher peak frequency data set, but the classic FWI solution degrades more rapidly.
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Xu, Yidong, Wei Xue, and Wenjing Shang. "A Pan-Function Model for the Utilization of Bandwidth Improvement and PAPR Reduction." Mathematical Problems in Engineering 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/658093.
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Aiming at the digital quadrature modulation system, a mathematical Pan-function model of the optimized baseband symbol signals with a symbol length of4Twas established in accordance with the minimum out-band energy radiation criterion. The intersymbol interference (ISI), symbol-correlated characteristics, and attenuation factor were introduced to establish the mathematical Pan-function model. The Pan-function was added to the constraints of boundary conditions, energy of a single baseband symbol signal, and constant-envelope conditions. Baseband symbol signals with the optimum efficient spectrum were obtained by introducing Fourier series and minimizing the Pan-function. The characteristics of the spectrum and peak-to-average power ratio (PAPR) of the obtained signals were analyzed and compared with the minimum shift keying (MSK) and quadrature phase-shift keying (QPSK) signals. The obtained signals have the characteristics of a higher spectral roll-off rate, less out-band radiation, and quasi-constant envelope. We simulated the performance of the obtained signals, and the simulation results demonstrate that the method is feasible.
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Zhang, Pan, Ru-Shan Wu, and Liguo Han. "Source-independent seismic envelope inversion based on the direct envelope Fréchet derivative." GEOPHYSICS 83, no. 6 (November 1, 2018): R581—R595. http://dx.doi.org/10.1190/geo2017-0360.1.
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Seismic envelope inversion (EI) uses low-frequency envelope data to recover long-wavelength components of the subsurface media. Conventional EI uses the same waveform Fréchet derivative as conventional full-waveform inversion. Due to linearization of the sensitivity operator (Born approximation), neither of these methods can yield good inversion results for media with strong preturbations, such as salt domes, when the source lacks low-frequency information. Because seismic envelope data contain large amount of ultra-low-frequency information and the direct envelope Fréchet derivative maps envelope data perturbation directly to velocity perturbation, the direct envelope inversion (DEI) method (based on the direct envelope Fréchet derivative) can handle such strong nonlinear inversion problems. However, this method is sensitive to source wavelet errors. We developed a source-independent DEI method. To achieve the source-independent objective function, we derive a convolution expression for the envelope data. We derive the gradient of the new objective function by using the direct envelope Fréchet derivative. Numerical tests conducted on a 2D salt model indicate that our method can achieve good reconstruction of salt bodies (strong velocity perturbations) and recover low-velocity background structures (weak velocity perturbations), despite using an inaccurate source wavelet.
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Wood, M. A., and D. E. Winget. "A Variational Approach to Understanding White Dwarf Evolution." International Astronomical Union Colloquium 114 (1989): 282–85. http://dx.doi.org/10.1017/s0252921100099711.
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The observed falloff in the white dwarf luminosity function at log (L/L⊙) ≈ −4.5 (Liebert, Dahn, and Monet 1988) is most easily explained as a result of the finite age of the Galactic disk. Using a simple perturbation approach as our method and a white dwarf evolution code as our tool, we have mapped the sensitivity of the ages of the model sequences in this low-luminosity regime to the uncertainties in the input physics and model parameters. We present here a preliminary overview of what we’ve learned.We have updated the White Dwarf Evolution Code of Lamb and Van Horn (1975) to include both carbon and oxygen in the core. We interpolate to the mixture composition using our pure-C and pure-O tables and the additive-volume technique (Fontaine, Graboske, and Van Horn 1977). The envelope subroutines calculate stratified H/He/C envelopes of essentially arbitrary layer masses within the range 0 to ∼ 10−2M*, and treat the composition transition zones as discontinuities. Because the equation of state tables referenced by the envelope routines do not include crystallization, a given sequence ends when the crystallization front reaches the core/envelope boundary.
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Huang, C., L. Dong, Y. Liu, and B. Chi. "Elastic envelope inversion using multicomponent seismic data without low frequency." Nonlinear Processes in Geophysics Discussions 1, no. 2 (December 5, 2014): 1757–802. http://dx.doi.org/10.5194/npgd-1-1757-2014.
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Abstract. Low frequency is a key issue to reduce the nonlinearity of elastic full waveform inversion. Hence, the lack of low frequency in recorded seismic data is one of the most challenging problems in elastic full waveform inversion. Theoretical derivations and numerical analysis are presented in this paper to show that envelope operator can retrieve strong low frequency modulation signal demodulated in multicomponent data, no matter what the frequency bands of the data is. With the benefit of such low frequency information, we use elastic envelope of multicomponent data to construct the objective function and present an elastic envelope inversion method to recover the long-wavelength components of the subsurface model, especially for the S-wave velocity model. Numerical tests using synthetic data for the Marmousi-II model prove the effectiveness of the proposed elastic envelope inversion method, especially when low frequency is missing in multicomponent data and when initial model is far from the true model. The elastic envelope can reduce the nonlinearity of inversion and can provide an excellent starting model.
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Xiaobao, Yu, Tan Zhongfu, Chen Kangting, Ju Liwei, and He Puyu. "Efficiency Evaluation for Smart Grid Management Based on Stochastic Frontier Model and Data Envelope Analyses Model." Mathematical Problems in Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/142764.
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For the technical and allocative efficiency evaluation of smart grid, this paper has proposed two methods. One is based on Data Envelopment Analysis and another is based on Stochastic Frontier Model. Among them, the former considered the dynamics of smart grid development and development dynamics is the influence parameter. The latter analyzed self-duality between the Cobb-Douglas production function and cost function; then, it deduced the smart grid resources optimization allocative efficiency evaluation model which can avoid price information needs of input factor in conventional allocative efficiency evaluation. The validity and rationality of the two methods are verified by a case study.
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Chen, Xin, Hongwei Yang, Min Guo, and Baoshu Yin. "(2 + 1)-Dimensional Coupled Model for Envelope Rossby Solitary Waves and Its Solutions as well as Chirp Effect." Mathematical Problems in Engineering 2017 (2017): 1–12. http://dx.doi.org/10.1155/2017/1378740.
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Using the method of multiple scales and perturbation method, a set of coupled models describing the envelope Rossby solitary waves in (2+1)-dimensional condition are obtained, also can be called coupled NLS (CNLS) equations. Following this, based on trial function method, the solutions of the NLS equation are deduced. Moreover, the modulation instability of coupled envelope Rossby waves is studied. We can find that the stable feature of coupled envelope Rossby waves is decided by the value of S. Finally, learning from the concept of chirp in the optical soliton communication field, we study the chirp effect caused by nonlinearity and dispersion in the propagation of Rossby waves.
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Nuzaihan Aras Agus Salim, Gan peng huai, and Ahmad Sanusi Hassan. "Simulation on Building Envelope Design using Biomimicry Conceptual of Palm Leaf Pattern for Self Cleaning Maintenance." Journal of Advanced Research in Applied Sciences and Engineering Technology 28, no. 3 (November 30, 2022): 376–92. http://dx.doi.org/10.37934/araset.28.3.376392.
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Contemporary architectural designs acting to increase the aesthetic value of the building’s overall perspective. The complexity of the maintenance works for the building envelope cleanliness becomes challenging in maintenance operations. Biomimicry – innovation inspired by nature, reveals an opportunity to simplify the cleaning process mentioned by infusing the self-cleaning characteristic of palm tree species on the design of building envelope. This research is intentionally to determine of the most ideal building envelope form that utilize the effect of the biomimicry conceptual as self-cleaning maintenance properties by finding the wind velocity to assess the dust flow behaviour. The basic architectural forms that commonly applied by the architects is used as a model to create the building forms in a way to find the physical self-cleaning characteristic by using the palm leaf pattern. By using the Autodesk Computational Fluid Dynamics (CFD) software, this tool is used to simulate the environmental situation and examine the efficiency of the self-cleaning function on different building models. The results are compared among the different models to identify the best building model that fully employ the self-cleaning function using the palm leaf pattern. The finding on self-cleaning properties of architectural forms is potentially developed the solution of sustainable building envelope design for a better functional and free maintenance.
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Şahin, İsmail Hakkı, and Coşku Kasnakoğlu. "Control of a small helicopter with linear matrix inequality-based design assuring stability and performance." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, no. 3 (September 24, 2019): 624–39. http://dx.doi.org/10.1177/0954410019877699.
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This article focuses on linear matrix inequality-based controller designs that can achieve stabilization and reference tracking for a small unmanned helicopter at various flight conditions. A nonlinear mathematical model of a small-scale helicopter is constructed. Then trim conditions are found and linearized around different equilibrium points. Local [Formula: see text] controllers are designed at trim conditions based on the local linear models. The pointwise controllers achieve local stability and performance, but fail at stabilization and tracking over the full envelope. A scheduling controller is built by blending the local controller outputs. In addition, grid-based [Formula: see text] controllers are designed at each operating point with common Lyapunov function. This allows controller scheduling between the adjacent design points with guaranteed stability and performance across the design envelope. Based on the family of linear systems which are obtained from the nonlinear model, an affine parameter-dependent model is built to exploit the approximate linear parameter dependency. Then, a parameter-dependent linear parameter varying controller is synthesized for the affine parameter-dependent model. Although local performance is satisfactory for all given design methods, local [Formula: see text] controllers and affine parameter-dependent controller cannot yield satisfactory performance over the full flight envelope apart from the grid-based controller with common Lyapunov function approach.
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Tang, Jiwei, Weicheng Xie, Xiaoliang Wang, and Cheng Chen. "Simulation and Analysis of Fluid–Solid–Thermal Unidirectional Coupling of Near-Space Airship." Aerospace 9, no. 8 (August 11, 2022): 439. http://dx.doi.org/10.3390/aerospace9080439.
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Based on the biaxial experiment data of the membrane material under hot and cold conditions, the mechanical properties calculation model of envelope material was established with consideration of the effects of varying stress ratios, stress magnitudes and temperatures on the mechanical properties of near-space airship material. Using the heat source model, Computational Fluid Dynamics (CFD) simulation, User-Defined Function (UDF), structural finite element analysis software and the user subroutine of an airship to define the behaviour of fabric material, the fluid–structure–thermal coupling model of airship envelopes was established. In addition, a near-space airship was selected as the research subject to calculate the diurnal temperature differences during the summer solstice and analyse the diurnal temperature distribution of the envelope. Under controlled environmental conditions, the deformation law of the near-space airship under the influence of fluid–structure–thermal coupling was calculated and summarised. The present fluid–solid–thermal coupling model takes into account the anisotropy of materials, temperature, stress magnitude, stress ratio and other influencing factors, which can more accurately reflect and predict the stress–strain distribution and the deformation law of near-space airships.
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Ревин, А. А., А. М. Михайлова, А. А. Конаков, В. В. Цыпленков, and В. Н. Шастин. "Долинно-орбитальное взаимодействие в германии, легированном донорами V группы: количественный анализ." Физика и техника полупроводников 55, no. 10 (2021): 901. http://dx.doi.org/10.21883/ftp.2021.10.51441.40.
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In the framework of the envelope function approximation, the wave functions of electrons localized at shallow donors P, As, Sb in Ge are calculated taking into account the valley-orbit coupling caused by the donor short-range potential. It is proposed an approach that makes it possible to include inter-valley mixing in the equation for a multi-component envelope function. The calculation of the effects of the valley-orbit interaction was carried out according to the perturbation theory, while the "bare" single-valley functions were found using the Ritz method. The parameters of the short-range part of the potential and the coefficient of inter-valley mixing were found individually for each donor, making it possible to obtain the best agreement with the results of experimental measurements of the energies of the singlet and triplet states. The envelope functions of the 1s(A1) and 1s(T2) states are calculated. The parameters of the valley-orbit interaction are found for each donor. It is also shown how the functions of the excited 2s, 2p0, 2p±, 3p0 states should be modified in order to remain orthogonal to the singlet and triplet functions within the framework of a more rigorous multivalley model.
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Bodoor, Khaldon, Sarah Shaikh, Paul Enarson, Sharmin Chowdhury, Davide Salina, Wahyu Hendrati Raharjo, and Brian Burke. "Function and assembly of nuclear pore complex proteins." Biochemistry and Cell Biology 77, no. 4 (August 25, 1999): 321–29. http://dx.doi.org/10.1139/o99-038.
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Nuclear pore complexes (NPCs) are extremely elaborate structures that mediate the bidirectional movement of macromolecules between the nucleus and cytoplasm. The current view of NPC organization features a massive symmetrical framework that is embedded in the double membranes of the nuclear envelope. It embraces a central channel of as yet ill-defined structure but which may accommodate particles with diameters up to 26 nm provided that they bear specific import/export signals. Attached to both faces of the central framework are peripheral structures, short cytoplasmic filaments, and a nuclear basket assembly, which interact with molecules transiting the NPC. The mechanisms of assembly and the nature of NPC structural intermediates are still poorly understood. However, mutagenesis and expression studies have revealed discrete sequences within certain NPC proteins that are necessary and sufficient for their appropriate targeting. In addition, some details are emerging from observations on cells undergoing mitosis where the nuclear envelope is disassembled and its components, including NPC subunits, are dispersed throughout the mitotic cytoplasm. At the end of mitosis, all of these components are reutilized to form nuclear envelopes in the two daughter cells. To date, it has been possible to define a time course of postmitotic assembly for a group of NPC components (CAN/Nup214, Nup153, POM121, p62 and Tpr) relative to the integral inner nuclear membrane protein LAP2 and the NPC membrane glycoprotein gp210. Nup153, a dynamic component of the nuclear basket, associates with chromatin towards the end of anaphase coincident with, although independent of, the inner nuclear membrane protein, LAP2. Assembly of the remaining proteins follows that of the nuclear membranes and occurs in the sequence POM121, p62, CAN/Nup214 and gp210/Tpr. Since p62 remains as a complex with three other NPC proteins (p58, p54, p45) during mitosis, and CAN/Nup214 maintains a similar interaction with its partner, Nup84, the relative timing of assembly of these additional four proteins may also be inferred. These observations suggest that there is a sequential association of NPC proteins with chromosomes during nuclear envelope reformation and the recruitment of at least eight of these precedes that of gp210. These findings support a model in which it is POM121 rather than gp210 that defines initial membrane-associated NPC assembly intermediates and which may therefore represent an essential component of the central framework of the NPC. Key words: nuclear pore complex, nucleoporin, mitosis, nuclear transport
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Ben-Haim, Yakov, and Isaac Elishakoff. "Non-Probabilistic Models of Uncertainty in the Nonlinear Buckling of Shells With General Imperfections: Theoretical Estimates of the Knockdown Factor." Journal of Applied Mechanics 56, no. 2 (June 1, 1989): 403–10. http://dx.doi.org/10.1115/1.3176097.
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A non-probabilistic, set-theoretical treatment of the buckling of shells with uncertain initial geometrical imperfections is presented. The minimum buckling load is determined as a function of the parameters which describe the (generally infinite) range of possible initial imperfection profiles of the shell. The central finding of this paper is a theoretical estimate of the knockdown factor as a function of the characteristics of the uncertainty in the initial imperfections. Two classes of set-theoretical models are employed. The first class represents the range of variation of the most significant N Fourier coefficients by an ellipsoidal set in N-dimensional Euclidean space. The minimum buckling load is then explicitly evaluated in terms of the shape of the ellipsoid. In the second class of models, the uncertainty in the initial imperfection profile is expressed by an envelope of functions. The bounding functions of this envelope can be viewed as a radial tolerance on the shape. It is demonstrated that a non-probabilistic model of uncertainty in the initial imperfections of shells is successful in determining the minimum attainable buckling load of an ensemble of shells and that such an approach is computationally feasible.
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Santoliquido, Filippo, Michela Mapelli, Nicola Giacobbo, Yann Bouffanais, and M. Celeste Artale. "The cosmic merger rate density of compact objects: impact of star formation, metallicity, initial mass function, and binary evolution." Monthly Notices of the Royal Astronomical Society 502, no. 4 (February 3, 2021): 4877–89. http://dx.doi.org/10.1093/mnras/stab280.
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ABSTRACT We evaluate the redshift distribution of binary black hole (BBH), black hole–neutron star binary (BHNS), and binary neutron star (BNS) mergers, exploring the main sources of uncertainty: star formation rate (SFR) density, metallicity evolution, common envelope, mass transfer via Roche lobe overflow, natal kicks, core-collapse supernova model, and initial mass function. Among binary evolution processes, uncertainties on common envelope ejection have a major impact: the local merger rate density of BNSs varies from ∼103 to ∼20 Gpc−3 yr−1 if we change the common envelope efficiency parameter from αCE = 7 to 0.5, while the local merger rates of BBHs and BHNSs vary by a factor of ∼2–3. The BBH merger rate changes by one order of magnitude, when 1σ uncertainties on metallicity evolution are taken into account. In contrast, the BNS merger rate is almost insensitive to metallicity. Hence, BNSs are the ideal test bed to put constraints on uncertain binary evolution processes, such as common envelope and natal kicks. Only models assuming values of αCE ≳ 2 and moderately low natal kicks (depending on the ejected mass and the supernovae mechanism), result in a local BNS merger rate density within the 90 per cent credible interval inferred from the second gravitational-wave transient catalogue.
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He, G., Y. Meng, J. Zhu, and S. Zhang. "A simplified model for calculating heat transfer through the double skin facade." Journal of Physics: Conference Series 2069, no. 1 (November 1, 2021): 012097. http://dx.doi.org/10.1088/1742-6596/2069/1/012097.
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Abstract Double skin façade (DSF) has been recognized as a flexible type of envelope that can adapt to various building needs, such as insulation, solar heat gain, ventilation, and shading. This adaption ability makes the DSF a potentially high performance envelope. However, the reliable calculation of the heat flow in the DSF has been a challenging task due to the complex heat transfer process involved in the DSF. In this study, we propose a simple model that aims to simplify the heat transfer calculation involved in the DSF. In this model, a characteristic function of heat transfer coefficient (CFHTC) was proposed for the heat transfer between the inner layer and the outside air, which would otherwise call the complex convective heat transfer in the cavity. We use experimental data to demonstrate that this function can be expressed as a function of the incident solar intensity. This CFHTC is supposed to be dependent on the geometry of the DSF. With the CFHTC, the calculation of the heat transfer between the inner layer of the DSF and the outside air is simplified and can be incorporated in energy simulation tools.
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Wieringa, Roeland, Antoine A. F. de Vries, Sabine M. Post, and Peter J. M. Rottier. "Intra- and Intermolecular Disulfide Bonds of theGP2b Glycoprotein of Equine Arteritis Virus: Relevance forVirus Assembly andInfectivity." Journal of Virology 77, no. 24 (December 15, 2003): 12996–3004. http://dx.doi.org/10.1128/jvi.77.24.12996-13004.2003.
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ABSTRACT Equine arteritis virus (EAV) is an enveloped, positive-strand RNA virus belonging to the family Arteriviridae of the order Nidovirales. EAV virions contain six different envelope proteins. The glycoprotein GP5 (previously named GL) and the unglycosylated membrane protein M are the major envelope proteins, while the glycoproteins GP2b (previously named GS), GP3, and GP4 are minor structural proteins. The unglycosylated small hydrophobic envelope protein E is present in virus particles in intermediate molar amounts compared to the other transmembrane proteins. The GP5 and M proteins are both essential for particle assembly. They occur as covalently linked heterodimers that constitute the basic protein matrix of the envelope. The GP2b, GP3, and GP4 proteins occur as a heterotrimeric complex in which disulfide bonds play an important role. The function of this complex has not been established yet, but the available data suggest it to be involved in the viral entry process. Here we investigated the role of the four cysteine residues of the mature GP2b protein in the assembly of the GP2b/GP3/GP4 complex. Open reading frames encoding cysteine-to-serine mutants of the GP2b protein were expressed independently or from a full-length infectious EAV cDNA clone. The results of these experiments support a model in which the cysteine residue at position 102 of GP2b forms an intermolecular cystine bridge with one of the cysteines of the GP4 protein, while the cysteine residues at positions 48 and 137 of GP2b are linked by an intrachain disulfide bond. In this model, another cysteine residue in the GP4 protein is responsible for the covalent association of GP3 with the disulfide-linked GP2b/GP4 heterodimer. In addition, our data highlight the importance of the correct association of the minor EAV envelope glycoproteins for their efficient incorporation into viral particles and for virus infectivity.
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Kaplan, Melike, and Arzu Akbulut. "A Mathematical Analysis of a Model Involving an Integrable Equation for Wave Packet Envelope." Journal of Mathematics 2022 (February 9, 2022): 1–10. http://dx.doi.org/10.1155/2022/3486780.
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This study investigates new optical solutions to a model with an integrable equation for wave packet envelopes. For this purpose, we have employed two reliable techniques involving the modified extended tanh function and the exponential rational function procedures. We have also given the 3D graphics of the obtained solutions.
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Zhao, Baojun, Ruyun Wang, and Hongwei Yang. "Three-Dimensional Coupled NLS Equations for Envelope Gravity Solitary Waves in Baroclinic Atmosphere and Modulational Instability." Mathematical Problems in Engineering 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/4276591.
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Envelope gravity solitary waves are an important research hot spot in the field of solitary wave. And the weakly nonlinear model equations system is a part of the research of envelope gravity solitary waves. Because of the lack of technology and theory, previous studies tried hard to reduce the variable numbers and constructed the two-dimensional model in barotropic atmosphere and could only describe the propagation feature in a direction. But for the propagation of envelope gravity solitary waves in real ocean ridges and atmospheric mountains, the three-dimensional model is more appropriate. Meanwhile, the baroclinic problem of atmosphere is also an inevitable topic. In the paper, the three-dimensional coupled nonlinear Schrödinger (CNLS) equations are presented to describe the evolution of envelope gravity solitary waves in baroclinic atmosphere, which are derived from the basic dynamic equations by employing perturbation and multiscale methods. The model overcomes two disadvantages: (1) baroclinic problem and (2) propagation path problem. Then, based on trial function method, we deduce the solution of the CNLS equations. Finally, modulational instability of wave trains is also discussed.
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Brouwers, M. G., C. W. Ormel, A. Bonsor, and A. Vazan. "How planets grow by pebble accretion." Astronomy & Astrophysics 653 (September 2021): A103. http://dx.doi.org/10.1051/0004-6361/202140476.
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Context. In the theory of pebble accretion, planets form by the subsequent accretion of solids (micron-sized dust and larger pebbles) and gas. The amount of nebular gas that a planet can bind is limited by its cooling rate, which is set by the opacity of its envelope. Accreting dust and pebbles contribute to the envelope opacity and, thus, influence the outcome of planet formation. Aims. Our aim is to model the size evolution and opacity contribution of solids inside planetary envelopes. We then use the resultant opacity relations to study emergent trends in planet formation. Methods. We design a model for the opacity of solids in planetary envelopes that accounts for the growth, fragmentation, and erosion of pebbles during their sedimentation. It also includes a separate dust component, which can be both replenished and swept up by encounters with pebbles, depending on the relative velocities. We formulate analytical expressions for the opacity of pebbles and dust and map out their trends as a function of depth, planet mass, distance, and accretion rate. Results. The accretion of pebbles rather than planetesimals can produce fully convective envelopes, but only in lower-mass planets that reside in the outer disk or in those that are accreting pebbles at a high rate. In these conditions, pebble sizes are limited by fragmentation and erosion, allowing them to pile up in the envelope. At higher planetary masses or reduced accretion rates, a different regime applies, where the sizes of sedimenting pebbles are only limited by their rate of growth. The opacity in this growth-limited regime is much lower and declines steeply with depth and planet mass but is invariant with the pebble mass flux. Our results imply that the opacity of a forming planet’s envelope cannot be approximated by a value that is constant with either depth or planet mass. Applying these results to the Solar System, we argue that Uranus and Neptune could not have maintained a sufficiently high opacity to avoid runaway gas accretion unless they both experienced sufficiently rapid accretion of solids and formed late.
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Hutchison, C. J., J. M. Bridger, L. S. Cox, and I. R. Kill. "Weaving a pattern from disparate threads: lamin function in nuclear assembly and DNA replication." Journal of Cell Science 107, no. 12 (December 1, 1994): 3259–69. http://dx.doi.org/10.1242/jcs.107.12.3259.
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The major residual structure that remains associated with the nuclear envelope following extraction of isolated nuclei or oocyte germinal vesicles with non-ionic detergents, nucleases and high salt is the lamina (Fawcett, 1966; Aaronson and Blobel, 1975; Dwyer and Blobel, 1976). The nuclear lamina is composed of intermediate filament proteins, termed lamins (Gerace and Blobel, 1980; Shelton et al., 1980), which polymerise to form a basket-weave lattice of fibrils, which covers the entire inner surface of the nuclear envelope and interlinks nuclear pores (Aebi et al., 1986; Stewart and Whytock, 1988; Goldberg and Allen, 1992). At mitosis, the nuclear envelope and the lamina both break down to allow chromosome segregation. As a consequence, each structure has to be rebuilt during anaphase and telophase, allowing cells an opportunity to reposition chromosomes (Heslop-Harrison and Bennett, 1990) and to reorganise looped chromatin domains (Franke, 1974; Franke et al., 1981; Hochstrasser et al., 1986), which may in turn control the use of subsets of genes. Because of the position that it occupies, its dynamics during mitosis and the fact that it is an essential component of proliferating cells, the lamina has been assigned a number of putative roles both in nuclear metabolism and in nuclear envelope assembly (Burke and Gerace, 1986; Nigg, 1989). However, to date there is little clear cut evidence that satisfactorily explains the function of the lamina in relation to its structure. In this Commentary we will describe some of the recent work that addresses this problem and attempt to provide a unified model for the role of lamins in nuclear envelope assembly and for the lamina in the initiation of DNA replication.
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Kim, Joowook, and Michael J. Brandemuehl. "Application Method of a Simplified Heat and Moisture Transfer Model of Building Construction in Residential Buildings." Energies 14, no. 14 (July 10, 2021): 4180. http://dx.doi.org/10.3390/en14144180.
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Several building energy simulation programs have been developed to evaluate the indoor conditions and energy performance of buildings. As a fundamental component of heating, ventilating, and air conditioning loads, each building energy modeling tool calculates the heat and moisture exchange among the outdoor environment, building envelope, and indoor environments. This paper presents a simplified heat and moisture transfer model of the building envelope, and case studies for building performance obtained by different heat and moisture transfer models are conducted to investigate the contribution of the proposed steady-state moisture flux (SSMF) method. For the analysis, three representative humid locations in the United States are considered: Miami, Atlanta, and Chicago. The results show that the SSMF model effectively complements the latent heat transfer calculation in conduction transfer function (CTF) and effective moisture penetration depth (EMPD) models during the cooling season. In addition, it is found that the ceiling part of a building largely constitutes the latent heat generated by the SSMF model.
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Tadić, M., and Z. Ikonić. "Multiband envelope function model of twinning boundaries and superlattices: electronic structure and infrared optical properties." Solid State Communications 110, no. 7 (April 1999): 397–402. http://dx.doi.org/10.1016/s0038-1098(99)00050-2.
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Bozler, Julianna, Huy Q. Nguyen, Gregory C. Rogers, and Giovanni Bosco. "Condensins Exert Force on Chromatin-Nuclear Envelope Tethers to Mediate Nucleoplasmic Reticulum Formation in Drosophila melanogaster." G3 Genes|Genomes|Genetics 5, no. 3 (March 1, 2015): 341–52. http://dx.doi.org/10.1534/g3.114.015685.
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Abstract Although the nuclear envelope is known primarily for its role as a boundary between the nucleus and cytoplasm in eukaryotes, it plays a vital and dynamic role in many cellular processes. Studies of nuclear structure have revealed tissue-specific changes in nuclear envelope architecture, suggesting that its three-dimensional structure contributes to its functionality. Despite the importance of the nuclear envelope, the factors that regulate and maintain nuclear envelope shape remain largely unexplored. The nuclear envelope makes extensive and dynamic interactions with the underlying chromatin. Given this inexorable link between chromatin and the nuclear envelope, it is possible that local and global chromatin organization reciprocally impact nuclear envelope form and function. In this study, we use Drosophila salivary glands to show that the three-dimensional structure of the nuclear envelope can be altered with condensin II-mediated chromatin condensation. Both naturally occurring and engineered chromatin-envelope interactions are sufficient to allow chromatin compaction forces to drive distortions of the nuclear envelope. Weakening of the nuclear lamina further enhanced envelope remodeling, suggesting that envelope structure is capable of counterbalancing chromatin compaction forces. Our experiments reveal that the nucleoplasmic reticulum is born of the nuclear envelope and remains dynamic in that they can be reabsorbed into the nuclear envelope. We propose a model where inner nuclear envelope-chromatin tethers allow interphase chromosome movements to change nuclear envelope morphology. Therefore, interphase chromatin compaction may be a normal mechanism that reorganizes nuclear architecture, while under pathological conditions, such as laminopathies, compaction forces may contribute to defects in nuclear morphology.
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Vogel, Alexander, Jörg Nikolaus, Katrin Weise, Gemma Triola, Herbert Waldmann, Roland Winter, Andreas Herrmann, and Daniel Huster. "Interaction of the human N-Ras protein with lipid raft model membranes of varying degrees of complexity." Biological Chemistry 395, no. 7-8 (July 1, 2014): 779–89. http://dx.doi.org/10.1515/hsz-2013-0294.
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Abstract Ternary lipid mixtures composed of cholesterol, saturated (frequently with sphingosine backbone), and unsaturated phospholipids show stable phase separation and are often used as model systems of lipid rafts. Yet, their ability to reproduce raft properties and function is still debated. We investigated the properties and functional aspects of three lipid raft model systems of varying degrees of biological relevance – PSM/POPC/Chol, DPPC/POPC/Chol, and DPPC/DOPC/Chol – using 2H solid-state nuclear magnetic resonance (NMR) spectroscopy, fluorescence microscopy, and atomic force microscopy. While some minor differences were observed, the general behavior and properties of all three model mixtures were similar to previously investigated influenza envelope lipid membranes, which closely mimic the lipid composition of biological membranes. For the investigation of the functional aspects, we employed the human N-Ras protein, which is posttranslationally modified by two lipid modifications that anchor the protein to the membrane. It was previously shown that N-Ras preferentially resides in liquid-disordered domains and exhibits a time-dependent accumulation in the domain boundaries of influenza envelope lipid membranes. For all three model mixtures, we observed the same membrane partitioning behavior for N-Ras. Therefore, we conclude that even relatively simple models of raft membranes are able to reproduce many of their specific properties and functions.
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Sudha, U. P. V., G. S. Deodhare, and K. Venkatraman. "A comparative assessment of flutter prediction techniques." Aeronautical Journal 124, no. 1282 (October 27, 2020): 1945–78. http://dx.doi.org/10.1017/aer.2020.84.
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ABSTRACTTo establish flutter onset boundaries on the flight envelope, it is required to determine the flutter onset dynamic pressure. Proper selection of a flight flutter prediction technique is vital to flutter onset speed prediction. Several methods are available in literature, starting with those based on velocity damping, envelope functions, flutter margin, discrete-time Autoregressive Moving Average (ARMA) modelling, flutterometer and the Houbolt–Rainey algorithm. Each approach has its capabilities and limitations. To choose a robust and efficient flutter prediction technique from among the velocity damping, envelope function, Houbolt–Rainey, flutter margin and auto-regressive techniques, an example problem is chosen for their evaluation. Hence, in this paper, a three-degree-of-freedom model representing the aerodynamics, stiffness and inertia of a typical wing section is used(1). The aerodynamic, stiffness and inertia properties in the example problem are kept the same when each of the above techniques is used to predict the flutter speed of this aeroelastic system. This three-degree-of-freedom model is used to generate data at speeds before initiation of flutter, during flutter and after occurrence of flutter. Using these data, the above-mentioned flutter prediction methods are evaluated and the results are presented.
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Yang, Xinzhen, Svetla Kurteva, Sandra Lee, and Joseph Sodroski. "Stoichiometry of Antibody Neutralization of Human Immunodeficiency Virus Type 1." Journal of Virology 79, no. 6 (March 15, 2005): 3500–3508. http://dx.doi.org/10.1128/jvi.79.6.3500-3508.2005.
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ABSTRACT The human immunodeficiency virus envelope glycoproteins function as trimers on the viral surface, where they are targeted by neutralizing antibodies. Different monoclonal antibodies neutralize human immunodeficiency virus type 1 (HIV-1) infectivity by binding to structurally and functionally distinct moieties on the envelope glycoprotein trimer. By measuring antibody neutralization of viruses with mixtures of neutralization-sensitive and neutralization-resistant envelope glycoproteins, we demonstrate that the HIV-1 envelope glycoprotein trimer is inactivated by the binding of a single antibody molecule. Virus neutralization requires essentially all of the functional trimers to be occupied by at least one antibody. This model applies to antibodies differing in neutralizing potency and to virus isolates with various neutralization sensitivities. Understanding these requirements for HIV-1 neutralization by antibodies will assist in establishing goals for an effective AIDS vaccine.
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Daidzic, Nihad E. "MATHEMATICAL MODEL AND SIMULATION OF FREE BALLOON LIFTOFF IN THE PRESENCE OF SURFACE WINDS." Aviation 26, no. 1 (March 23, 2022): 22–31. http://dx.doi.org/10.3846/aviation.2022.16621.
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A mathematical model of free balloon launches in windy conditions is based on the conservation of the linear momentum in horizontal and vertical axes. Linear momentum conservation equations are represented by a set of four nonlinear first-order ODEs. Some ODEs were solved analytically, while the nonlinear Riccati ODE with variable coefficients for the vertical acceleration was solved using numerical ODE solvers. Transient aerodynamic lift and horizontal drag are caused by the slip flow over the balloon envelope. It takes free balloon ten half times to reach 90.9% of the wind velocity in a step function response. A launch condition was developed in terms of the minimum required envelope temperature for which the net aerostatic lift overcomes inert weight of a balloon. Perturbation analysis was used to explore changes in the net aerostatic lift. Simulations were performed to cases with and without envelope distortion and enhanced cooling due to forced convection. Since all balloon takeoffs are performed downwind, obstacle clearance becomes an issue due to rapid loss of aerodynamic lift. Balloons may stop climbing and even start descending shortly after liftoff despite intense heating representing real hazard.
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Jiang, Kaili, Xiaomin Chen, Qiuming Zhu, Lele Chen, Dazhuan Xu, and Bing Chen. "A Novel Simulation Model for Nonstationary Rice Fading Channels." Wireless Communications and Mobile Computing 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/8086073.
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In this paper, we propose a new simulator for nonstationary Rice fading channels under nonisotropic scattering scenarios, as well as the improved computation method of simulation parameters. The new simulator can also be applied on generating Rayleigh fading channels by adjusting parameters. The proposed simulator takes into account the smooth transition of fading phases between the adjacent channel states. The time-variant statistical properties of the proposed simulator, that is, the probability density functions (PDFs) of envelope and phase, autocorrelation function (ACF), and Doppler power spectrum density (DPSD), are also analyzed and derived. Simulation results have demonstrated that our proposed simulator provides good approximation on the statistical properties with the corresponding theoretical ones, which indicates its usefulness for the performance evaluation and validation of the wireless communication systems under nonstationary and nonisotropic scenarios.
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Tapley, Erin C., Nina Ly, and Daniel A. Starr. "Multiple mechanisms actively target the SUN protein UNC-84 to the inner nuclear membrane." Molecular Biology of the Cell 22, no. 10 (May 15, 2011): 1739–52. http://dx.doi.org/10.1091/mbc.e10-08-0733.
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Approximately 100 proteins are targeted to the inner nuclear membrane (INM), where they regulate chromatin and nuclear dynamics. The mechanisms underlying trafficking to the INM are poorly understood. The Caenorhabditis elegans SUN protein UNC-84 is an excellent model to investigate such mechanisms. UNC-84 recruits KASH proteins to the outer nuclear membrane to bridge the nuclear envelope (NE), mediating nuclear positioning. UNC-84 has four targeting sequences: two classical nuclear localization signals, an INM sorting motif, and a signal conserved in mammalian Sun1, the SUN—nuclear envelope localization signal. Mutations in some signals disrupt the timing of UNC-84 nuclear envelope localization, showing that diffusion is not sufficient to move all UNC-84 to the NE. Thus targeting UNC-84 requires an initial step that actively transports UNC-84 from the peripheral endoplasmic reticulum to the NE. Only when all four signals are simultaneously disrupted does UNC-84 completely fail to localize and to function in nuclear migration, meaning that at least three signals function, in part, redundantly to ensure proper targeting of UNC-84. Multiple mechanisms might also be used to target other proteins to the INM, thereby ensuring their proper and timely localization for essential cellular and developmental functions.
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Jausovec, Marko, and Metka Sitar. "Comparative Evaluation Model Framework for Cost-Optimal Evaluation of Prefabricated Lightweight System Envelopes in the Early Design Phase." Sustainability 11, no. 18 (September 18, 2019): 5106. http://dx.doi.org/10.3390/su11185106.
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This paper proposes an extended comparative evaluation model framework (ECEMF) that highlights two objectives: (1) a specific economic evaluation method for the cost-optimisation of prefabricated lightweight system envelopes to achieve a greater value of the building, and (2) a comparative evaluation model framework usable by different profiles of stakeholders, when adopting the decision on the most optimal envelope type in the early design phase. Based on the proposed framework, the analysis was conducted for the case study building representing a small single-family house located in Slovenia. The methodology applied is based on the life cycle cost (LCC) including construction, operation, maintenance, and refurbishment costs, but excluding dismantling, disposal, and reuse, for the period of 50 years’ lifetime of the building which combines the Building Information Modelling (BIM) with Value for Money (VfM) assessment. To exploit the automated evaluation process in the computing environment, several tools were used, including Archicad for BIM in combination with Legep software for LCC. On one hand, the model confirms the assumption that the optimal value parameters of a building do not only depend on the typical costs related to high-performance buildings. On the other hand, from the stakeholders’ view, the model enables the choice of the optimal solution regarding the envelope type to be made in the early design phase. In this view, the model could function as an important decision tool, with a direct economic impact on the value.
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Król, Barbara, and Krzysztof Kupiec. "Optimal Location of the Active Thermal Insulation Layer in the Building Envelope." Thermo 3, no. 1 (February 8, 2023): 176–200. http://dx.doi.org/10.3390/thermo3010011.
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One of the modern methods of protecting against building heat losses is active thermal insulation (ATI). In winter conditions, ATI works by supplying heat into the envelope, which increases the temperature in the ATI layer. A low-temperature renewable energy medium feeds the active insulation layer directly, e.g., through solar or geothermal energy. A model for heat transfer through the building envelope with an ATI layer was developed. The numerical simulations verified the simplifying assumptions in the model. A relationship was derived to determine the optimal location of the ATI layer in the envelope. The objective function of the summed costs of the thermal energy supplied to the internal space and the envelope was assumed. We took into account the fact that the unit price of energy supplied to the ATI layer is lower than the price of the energy supplied to the internal space. Based on the results of the measurements carried out in a building facility with the ATI layer installed, the actual savings effects due to the ATI layer were compared to the calculated values.
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Akbarian, Mojtaba, Esmaeil Najafi, Reza Tavakkoli-Moghaddam, and Farhad Hosseinzadeh-Lotfi. "A Network-Based Data Envelope Analysis Model in a Dynamic Balanced Score Card." Mathematical Problems in Engineering 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/914108.
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Performance assessment during the time and along with strategies is the most important requirements of top managers. To assess the performance, a balanced score card (BSC) along with strategic goals and a data envelopment analysis (DEA) are used as powerful qualitative and quantitative tools, respectively. By integrating these two models, their strengths are used and their weaknesses are removed. In this paper, an integrated framework of the BSC and DEA models is proposed for measuring the efficiency during the time and along with strategies based on the time delay of the lag key performance indicators (KPIs) of the BSC model. The causal relationships during the time among perspectives of the BSC model are drawn as dynamic BSC at first. Then, after identifying the network-DEA structure, a new objective function for measuring the efficiency of nine subsidiary refineries of the National Iranian Oil Refining and Distribution Company (NIORDC) during the time and along with strategies is developed.
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McGee, Matthew D., Regina Rillo, Amy S. Anderson, and Daniel A. Starr. "UNC-83 Is a KASH Protein Required for Nuclear Migration and Is Recruited to the Outer Nuclear Membrane by a Physical Interaction with the SUN Protein UNC-84." Molecular Biology of the Cell 17, no. 4 (April 2006): 1790–801. http://dx.doi.org/10.1091/mbc.e05-09-0894.
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UNC-84 is required to localize UNC-83 to the nuclear envelope where it functions during nuclear migration. A KASH domain in UNC-83 was identified. KASH domains are conserved in the nuclear envelope proteins Syne/nesprins, Klarsicht, MSP-300, and ANC-1. Caenorhabditis elegans UNC-83 was shown to localize to the outer nuclear membrane and UNC-84 to the inner nuclear membrane in transfected mammalian cells, suggesting the KASH and SUN protein targeting mechanisms are conserved. Deletion of the KASH domain of UNC-83 blocked nuclear migration and localization to the C. elegans nuclear envelope. Some point mutations in the UNC-83 KASH domain disrupted nuclear migration, even if they localized normally. At least two separable portions of the C-terminal half of UNC-84 were found to interact with the UNC-83 KASH domain in a membrane-bound, split-ubiquitin yeast two-hybrid system. However, the SUN domain was essential for UNC-84 function and UNC-83 localization in vivo. These data support the model that KASH and SUN proteins bridge the nuclear envelope, connecting the nuclear lamina to cytoskeletal components. This mechanism seems conserved across eukaryotes and is the first proposed mechanism to target proteins specifically to the outer nuclear membrane.
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Teng, Rui Jing, Xiao Jun Zhou, Chen Long Yang, and Zhao Li. "Application of Improved LMD in Gear Fault Diagnosis." Advanced Materials Research 734-737 (August 2013): 2930–33. http://dx.doi.org/10.4028/www.scientific.net/amr.734-737.2930.
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Local mean and envelope functions are obtained by moving average method in local mean deocompsition (LMD). If the moving average step length is not suitable, the calculation will be very slow. LMD based on cubic interpolation was proposed, which makes the calculation much faster. To restrain the endpoint effect, the extension model based on the mean generating function was proposed. Analysis results of simulation signal and gear fault data show that the proposed method is effective .
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Cho, Jaeho, Jaeyoul Chun, Inhan Kim, and Jungsik Choi. "QFD Based Benchmarking Logic Using TOPSIS and Suitability Index." Mathematical Problems in Engineering 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/851303.
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Users’ satisfaction on quality is a key that leads successful completion of the project in relation to decision-making issues in building design solutions. This study proposed QFD (quality function deployment) based benchmarking logic of market products for building envelope solutions. Benchmarking logic is composed of QFD-TOPSIS and QFD-SI. QFD-TOPSIS assessment model is able to evaluate users’ preferences on building envelope solutions that are distributed in the market and may allow quick achievement of knowledge. TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) provides performance improvement criteria that help defining users’ target performance criteria. SI (Suitability Index) allows analysis on suitability of the building envelope solution based on users’ required performance criteria. In Stage 1 of the case study, QFD-TOPSIS was used to benchmark the performance criteria of market envelope products. In Stage 2, a QFD-SI assessment was performed after setting user performance targets. The results of this study contribute to confirming the feasibility of QFD based benchmarking in the field of Building Envelope Performance Assessment (BEPA).