323,524 research outputs found
Strengthening Smith Predictor Robustness via Azadi Controller (Positive Feedback)
No full text438-443<span style="mso-ansi-language:EN-AU;font-weight:normal;mso-bidi-font-weight:
bold" lang="EN-AU">A Smith Predictor Controller is one the best nominates for the plants
with large time delays. The controller theoretically performs perfect for
suppressing the plant vibrations with strong consequences. However, when the
plant model have some uncertainties from the nominate values, the robustness of
controller which is based on the plant model violates, and converse results
attains. Many researchers have challenged to overcome these uncertainties on
the plant models either by fine computing the plant models, or by introducing
some other compensators to the Smith predictors. However, when the
uncertainties on the plant dynamics overstates, Smith Predictor cannot achieves
its main function. In this research work,
I applied Azadi controller to the Smith Predictor, and testify the system for
very large variations on the plant dynamic. Azadi Controller actually is an
adaptive controller with just one simple variable gain. This gain varies
adaptively to yield worthy results. The stability analysis, and simulation
results fully confirm that having Azadi controller augmented to the Smith
Predictor can be appropriate for the plants with large uncertainty time delays.
Azadi controller’s initiative division and novelty has approved through patent
No. 75315 registered in Iranian industrial and intellectual property office.<span style="mso-ansi-language:EN-US;font-weight:normal;mso-bidi-font-weight:
bold" lang="EN-US">
</span
Systematically convergent method for accurate total energy calculations with localized atomic orbitals
No full textWe introduce a method for solving a self consistent electronic calculation within localized atomic orbitals, that allows us to converge to the complete basis set (CBS) limit in a stable, controlled, and systematic way. We compare our results with the ones obtained with a standard quantum chemistry package for the simple benzene molecule. We find perfect agreement for small basis set and show that, within our scheme, it is possible to work with a very large basis in an efficient and stable way. Therefore we can avoid to introduce any extrapolation to reach the CBS limit. In our study we have also carried out variational Monte Carlo (VMC) and lattice regularized diffusion Monte Carlo (LRDMC) with a standard many-body wave function (WF) defined by the product of a Slater determinant and a Jastrow factor. Once the Jastrow factor is optimized by keeping fixed the Slater determinant provided by our new scheme, we obtain a very good description of the atomization energy of the benzene molecule only when the basis of atomic orbitals is large enough and close to the CBS limit, yielding the lowest variational energies
Fate of the Resonating Valence Bond in Graphene
No full textWe apply a variational wave function capable of describing qualitatively and quantitatively the so-called ”resonating valence bond” (RVB) in realistic materials, by improving standard ab initio calculations by means of quantum Monte Carlo methods. In this framework we clearly identify the Kekulé and Dewar contributions to the chemical bond of the benzene molecule and establish the corresponding RVB energy of these structures (≃0.01 eV/atom). We apply this method to unveil the nature of the chemical bond in undoped graphene, providing an estimate of the RVB energy gain, and show that this picture remains only within a small ”resonance length” of a few atomic units
Numerical Simulation of Contact Acoustic Nonlinearities in Damaged CFRP Laminates Through Laser-Induced Guided Waves
Full text linkThe importance of Carbon Fiber Reinforced Polymer (CFRP) materials in numerous industries demands more accurate and timely damage identification methods. Delamination, a typical damage mechanism, heavily affects laminates' performance and requires prompt detection to ensure the safeness and operability of CFRP structures. This paper explores the use of guided waves to excite contact acoustic nonlinearities (CANs) in a damaged quasi-isotropic CFRP laminate. Delamination-induced CANs are exploited to identify the shape and position of delamination. The Finite Element Method (FEM) is used to model CAN generation and propagation. In the numerical model, a Gaussian laser beam heating the laminate surface induces Ultrasonic Guided Wave (UGW) propagation. The vertical displacement of the damaged laminate is measured by simulating a Scanning Laser Doppler Vibrometer (SLDV). Using 2D Continuous Wavelet Transformation (2D-CWT), the 2D wavefield is converted into the spatiotemporal frequency domain and analyzed to detect resonance frequencies. Two case scenarios are analyzed for a 16 plies CFRP laminate: delamination between the 13th and 14th layer (near the surface) and delamination between the 4th and 5th layer (near the bottom). The ability of this method to detect and assess both shallow and deep delamination in CFRP laminates is confirmed
PROPAGATION OF GUIDED WAVES IN DAMAGED FIBER REINFORCED POLYMER LAMINATES: NUMERICAL MODELLING
Full text linkDamage diagnosis in Carbon Fiber Reinforced Polymers (CFRPs) is increasingly crucial due to the rising demand for composite products in several industries. Intralaminar transverse cracks (TCs) are among the most common damages in composite laminates under loading. Hence, early TC detection is vital for reliable structural health monitoring (SHM) and design of CFRP structures. In this study, theTC-induced local wave mode conversion phenomenon is used as a diagnostic tool to identify single TC orientation in a damaged cross-ply CFRP laminate. The TC-induced mode conversion in laminates is modelled using the Finite Element Method (FEM). In the numerical model, Laser-induced Ultrasonic Guided Wave (LUGW) propagation is simulated using an inclined Gaussian laser beam acting on the surface of the laminate. Then, the vertical displacement field of the damaged laminate is analyzed to observe the symmetric (S0) wave mode conversion into antisymmetric (A0) mode. Finally, the 2D wavefield is transformed, using 3D-FFT, into the kx-ky wavenumber domain and analyzed to verify the presence of A0 mode components. This method is applied to three orientations of TC to wave direction, namely: 90°, 30°, and 45°, while undamaged plate is considered as reference. The numerical procedure confirmed its capability in early detection and assessment of TC in CFRP laminates
Resonating Valence Bond wave function with molecular orbitals: application to first-row molecules
Full text linkWe introduce a method for accurate quantum chemical calculations based on a simple variational wave function, defined by a single geminal that couples all the electrons into singlet pairs, combined with a real space correlation factor. The method uses a constrained variational optimization, based on an expansion of the geminal in terms of molecular orbitals. It is shown that the most relevant non-dynamical correlations are correctly reproduced once an appropriate number n of molecular orbitals is considered. The value of n is determined by requiring that, in the atomization limit, the atoms are described by Hartree-Fock Slater determinants with Jastrow correlations. The energetics, as well as other physical and chemical properties, are then given by an efficient variational approach based on standard quantum Monte Carlo techniques. We test this method on a set of homonuclear (Be2, B2, C2, N2, O2, and F2) and heteronuclear (LiF, and CN) dimers for which strong non-dynamical correlations and/or weak van der Waals interactions are present
Houscaper: Developing a tool for easy access of architectural polygonization using the Boolean Marching Cubes Algorithm
No full textThe demand for lower construction costs comes at the price of duplicating architectural designs. As a result, the misperception that modular architecture is repetitive prevails. However, the developments in computational design and MMC (modern methods of construction) can suggest a standardized manufacturing approach to provide mass customization. The research explores the computation of Modular building envelope systems using the Boolean marching cube algorithm under the premise of a ‘participatory generative design framework’ of the 'GO-Design' developed by Pirouz Nourian and Shervin Azadi [1]. In this project, (1) a set of architectural tilesets is developed that incorporates mass-customization by providing the potential for generating various configurations, and (2) a prototype of an interactive digital tool is established to enable future inhabitants to customize the configuration of their modular houses based on the predefined tileset. The algorithm is developed and applied in the Rhino & Grasshopper environment. The BMC algorithm reads the voxels' labels pertaining to each cube's vertices (a collection of 8 neighboring voxels) to load and choose the corresponding tile from a predefined tileset. The project's focus is the design of such a tileset, its engineering consistency, and architectural coherence. As an input, a voxelated massing will be the input, possibly later accompanied by a colored zoning scheme. and the output will be a modular architectural assembly. This workflow is envisaged to become a procedural component of a Configure, Price, & Quote (CPQ) system for the industrialization of mass customizable housing.Architecture, Urbanism and Building Sciences | Building Technolog
Freedom at a Cost: Human Suffering and the Irony of Independence in Chaman Nahal’s Azadi
Full text linkChaman Nahal’s Azadi (1975) stands as one of the most compelling fictional accounts of the 1947 Partition of India foregrounding the lived experiences of displacement, identity fragmentation, and ethical disintegration that accompanied the achievement of political independence. This article examines Azadi as a narrative of forced migration and refugee trauma, arguing that the novel exposes the paradox of freedom attained through mass suffering. Drawing upon Trauma theory and Identity studies and Partition historiography, the article analyzes how Partition transforms ordinary citizens into refugees and how displacement extends beyond physical exile to encompass psychological alienation and moral erosion. Episodes of extreme violence, self-sacrifice, and ethical compromise reveal the normalization of brutality during Partition, marking a profound moral collapse within both society and the emerging nation-state. The assassination of Mahatma Gandhi at the novel’s conclusion is read as a symbolic culmination of this ethical failure, underscoring the disjunction between nationalist ideals and lived realities. By foregrounding refugee suffering and moral disillusionment, Azadi challenges triumphalist narratives of independence and insists on remembering Partition through its human cost. The article concludes that Nahal’s novel remains a vital literary intervention, offering a critical lens through which displacement and identity loss can be understood as enduring legacies of decolonization
The First Season (2009) of Archaeological Research by the Iranian-Italian Joint Expedition at Qaleh Kutchek, Halil Valley (Jiroft, Kerman Province, SE Iran)
No full textFrom January 2009 a campaign of systematic study began, conducted by a joint mission of archaeologists and topographers, Iranians and Italians, in the archaeological area of Qaleh Kutchek, about 20 km S of Jiroft, Kerman province, in southern Iran. During this first campaign were carried out a series of preliminary topographical studies aimed at the realization of a basic cartography of the area and for the acquisition of data relevant for the implementation of a webGIS of the study area. The survey allowed us to reconstruct preliminary chronological evaluations in order to understand the settlement life and to relate the site to the latest epigraphic sources
Jin Jiyan Azadi: Kurdish women resisting in the 4 parts of Kurdistan
No full textThe death of the Kurdish woman Jina Amini in September 2022 sparked an inferno of protests throughout Iran, under the banner of “Jin, Jiyan, Azadi.” This Kurdish language slogan, which translates to “Women, Life, Freedom,” soon showed up on banners carried throughout the cities of Eastern Kurdistan (northwest Iran), and quickly became the official slogan of what many deemed a new “Iranian Revolution.” It was not long until “Jin, Jiyan, Azadi” was projected onto the Brandenburg Gate in Berlin, chanted at the Cannes Film Festival, and shouted by Western women politicians in European Parliaments. Women all across social media even began cutting pieces of their hair before reciting the phrase into their web cameras. [...
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