Transformation Method Research Articles

Study Of Tandem Rotor Dual Wake Interaction With Downstream Stator Under Unsteady Numerical Approach

Abstract This paper highlights the intricate rotor-stator interaction between a tandem bladed rotor and a single-bladed stator in the light of unsteady numerical simulations. A low speed tandem bladed compressor stage has been conceptualized and experimentally validated against targeted performance goal. With the evident pressure rise capability of the tandem bladed compressor stage, it becomes obligatory to investigate the rotorstator interaction owing to its dominant effect on overall stage performance. The multi-passage rotor-stator unsteady simulations have been performed using blade transformation methods in ANSYS CFX. Due to the presence of two highly loaded rotor blades, the tandem rotor exhibits peculiar rotorstator interaction in terms of multiple wake impingement on the stator. Incorporating tandem blading on the rotor instead of the stator (which is more common) constricts the design envelope in terms of choice of blade axial overlap and percentage pitch. The variation of aerodynamic loading from hub to tip for both the rotor blades results in spanwise varying wake strength. The initially distinct wake structures merge resulting into a thicker wake. Additionally, the rotor blades are highly loaded in the tip region which results in the complex interaction between end-wall boundary layer and tip leakage flow. Cumulatively, these conditions constitute a challenging aerodynamic field for the downstream stator. The study focuses on the qualitative interaction between the rotor wakes and blockage with the downstream stator and put forwards some aspects of the tandem rotor-single stator stage design especially for core compressors of aero engine application.

Porous Single‐Crystal Nitrides for Enhanced Pseudocapacitance and Stability in Energy Storage Applications

AbstractSupercapacitors have emerged as a prominent area of research in energy storage technology, primarily because of their high power density and notable stability compared to batteries. However, their practical implementation is hindered by their low energy densities and insufficient long‐term stability. In this study, bulk porous Nb4N5 and Ta3N5 single crystals with excellent pseudocapacitance and electrical conductivity are successfully prepared by solid‐phase transformation method. These monolithic porous single crystals (PSC) exhibit a long‐range ordered crystalline architecture and substantial specific surface area, which facilitate rapid charge transport and ion diffusion within the electrolyte‐permeated crystal lattice. Notably, the areal capacitance of the porous Nb4N5 single crystals is 12.9 F cm−2 at a current density of 6 mA cm−2 and 35.08 F cm−2 at a scan rate of 1 mV s−1. Furthermore, the energy density reached 1.79 mWh cm−2 at a power density of 20 mW cm−2, demonstrating their high energy storage capability. Moreover, these porous Nb4N5 single crystals exhibited robust capacitance retention and exceptional cycling stability, making them promising candidates for use as electrodes in energy storage applications. These results underscore the significant potential of porous metal nitride single crystals in advancing the field of capacitive energy storage.

Podophyllotoxin and Aryltetralin Lignans: Methods for the Synthesis of Rings A, B, C, D

Podophyllotoxin, its derivatives and structural analogues are an extensive group of aryl-tetralin-lignans of interest in pharmacology due to their promising anticancer and antitumor activity. The synthesis methods that have been proposed to date seek to resolve synthetic, stereochemical, pharmacodynamic and environmental aspects. In this review we have updated and brought together different classifications of lignan and podophyllotoxin synthesis. Transformation methods focus on the strategies used to form or functionalize rings A, B, C and D, as well as the configuration of the system of four stereogenic centers that fuse rings C and D.

Quantification of electrochemically accessible iridium oxide surface area with mercury underpotential deposition.

Research drives development of sustainable electrocatalytic technologies, but efforts are hindered by inconsistent reporting of advances in catalytic performance. Iridium-based oxide catalysts are widely studied for electrocatalytic technologies, particularly for the oxygen evolution reaction (OER) for proton exchange membrane water electrolysis, but insufficient techniques for quantifying electrochemically accessible iridium active sites impede accurate assessment of intrinsic activity improvements. We develop mercury underpotential deposition and stripping as a reversible electrochemical adsorption process to robustly quantify iridium sites and consistently normalize OER performance of benchmark IrOx electrodes to a single intrinsic activity curve, where other commonly used normalization methods cannot. Through rigorous deconvolution of mercury redox and reproportionation reactions, we extract net monolayer deposition and stripping of mercury on iridium sites throughout testing using a rotating ring disk electrode. This technique is a transformative method to standardize OER performance across a wide range of iridium-based materials and quantify electrochemical iridium active sites.

Potential damage area detection of bridges based on single-temporal point cloud

Abstract With advantages of 3D representation, non-contact measurements and intensive sampling capability, it has been a research hotspot to detect the potential damage area of bridges with point cloud by TLS. However, TLS is commonly used to detect a potential damage area by comparing multi-temporal point cloud data, which limits the timeliness of bridge inspection. Therefore, aiming to accurately detect the potential damage areas of bridges with single-temporal point cloud, this paper proposes a normalized normal vector constrained coordinate transformation method. First, the distribution of sharp features is revealed in a single-temporal point cloud at potential damage areas, and a neighborhood growth method constrained by the normal distance is proposed to eliminate the sharp features in point cloud, which is prone to cause incorrect or missing curvature values from point cloud. Second, a normalized normal vector constrained coordinate transformation method is proposed to construct Gaussian curvature model, which can improve the accuracy of point cloud curvature and accurately detect the potential damage areas in bridges. At last, an evaluation criterion is proposed to quantify the bridge condition by integrating the characteristics of small-span concrete bridges in urban areas with actual damage data from the experimental bridges. The experimental results show that the proposed method can effectively detect the potential damage areas of the measured bridges.

Solving Paths Search Problems in Complex Graphs

The construction of models of various systems is associated with the enumeration of the values of the parameters of the elements of the structure and taking into account all the characteristics of operation and interaction of components to find a certain set of solutions that determine the configuration of the system. Such tasks belong to enumeration type tasks and imply that some of the next solutions from this set are obtained from the previous solution in a certain order. It is known that any problem of the enumeration type is solved only by methods of exhaustive search, and other methods for their enumeration do not exist yet. The paper presents a new method of searching paths in a graph – the method of node-graph transformation. The proposed method, unlike the existing ones, allows one to search all directed simple paths in an oriented graph of arbitrary structure much faster. In the known graph search methods (Breadth First Search and Depth First Search), the object of the search is a path. The total number of such paths in the graph determines the size of the search space. The main idea of the node-graph transformation method is to significantly reduce the size of the search space by enlarging the search objects. The enlargement of enumeration objects is performed by clustering paths into combinatorial objects that concentrate some set of paths of the same length according to certain rules. These combinatorial objects are called node-graphs. A node-graph refers to center-peripheral combinatorial objects, and specific node-graph transformation operations have been developed to enumerate all paths in the graph, which allow finding new paths based on previous paths. The method can be used as a basic toolkit to reduce the dimensionality of the search space for solutions to NP-complete problems while maintaining the universality and accuracy of the full search.

Anonymization of Voices in Spaces for Civic Dialogue: Measuring Impact on Empathy, Trust, and Feeling Heard

Anonymity is a powerful component of many participatory media platforms that can afford people greater freedom of expression and protection from external coercion and interference. However, it can be difficult to effectively implement on platforms that leverage spoken language due to distinct biomarkers present in the human voice. In this work, we explore the use of voice anonymization methods within the context of a technology-enhanced civic dialogue network based in the United States, whose purpose is to increase feelings of agency and being heard within civic processes. Specifically, we investigate the use of two different speech transformation and synthesis methods for anonymization: voice conversion (VC) and text-to-speech (TTS). Through a series of two studies, we examine the impact that each method has on 1) the empathy and trust that listeners feel towards a person sharing a personal story, and 2) a speaker's own perception of being heard, finding that voice conversion is an especially suitable method for our purposes. Our findings open up interesting potential research directions related to anonymous spoken discourse, as well as additional ways of engaging with voice-based civic technologies.

Establishment and application of highly efficient regeneration, genetic transformation and genome editing system for cucurbitacins biosynthesis in Hemsleya chinensis

Background Hemsleya Chinensis is a perennial plant in the Cucurbitaceae family containing antibacterial and anti-inflammatory compounds. The lack of genetic transformation systems makes it difficult to verify the functions of genes controlling important traits and conduct molecular breeding in H. chinensis.ResultsHighly efficient calli were induced on MS medium added 1.5 mg·L− 1 6-benzylaminopurine (6-BA) and 0.02 mg·L− 1 1-naphthylacetic acid (NAA) with high efficiency (> 95%). The frequency of shoot induction was increased to 90% with a plant growth regulator combination of 1.5 mg·L− 1 6-BA and 0.1 mg·L− 1 NAA. Our results also showed that 100% of shoot regeneration was achieved in a shoot regeneration medium. Additionally, more than 92% of kanamycin-resistant plants were confirmed. Furthermore, we achieved 42% genome editing efficiency by applying this transformation method to HcOSC6, a gene that catalyzes the formation of cucurbitadienol. HPLC analysis showed OE-HcOSC6 lines exhibited significantly higher cucurbitadienol levels than the genome-edited lines. Transcriptomic analysis revealed that some downstream genes related to cucurbitadienol biosynthesis, such as HcCYP87D20, HcCYP81Q58, and HcSDR34, were up-regulated in OE lines and down-regulated in mutants.ConclusionsHere, we established a process for regeneration, transformation, and genome editing of H. chinensis using stem segments. This provides valuable insight into the underlying molecular mechanisms of medicinal compound production. By combining high-efficiency tissue culture, transformation, and genome editing systems, we provide a powerful platform that supports functional research on molecular mechanisms of secondary metabolism.

Linear parameter varying μ synthesis robust control of CDC semi‐active suspension system for nonlinearity and uncertainty

AbstractBecause the continuous damping control (CDC) semi‐active suspension system has complex nonlinear and uncertain characteristics that can significantly affect the performance of the system. And in the controller design process, achieving a balance of multiple performance objectives is often difficult. Therefore, this paper designs a linear parameter varying (LPV) μ synthesis robust controller for the vibration suppression and multi‐objective control of a 7‐degree‐of‐freedom (7‐DOF) vehicle suspension system equipped with CDC dampers. Firstly, the nonlinear force model of the solenoid valve CDC damper is developed based on the actual damping variation. Considering the nonlinear forces of the coil springs, the nonlinear model of the 7‐DOF suspension system is expressed as LPV form. Further, the linear fractional transformation (LFT) method is used to analyze and reconstruct the system model for multiple parameter uncertainties of the suspension. The actuator time delays are also simulated through a frequency domain transfer function, which is considered to be an unmodeled dynamic at the input of the system. Finally, an LPV‐μ synthesis robust controller based on nonlinearity and mixed uncertainty is designed to improve car ride comfort and achieve the best relationship between comfort and handling stability. Simulation and experimental results under random disturbance conditions show that the LPV‐μ synthesis controller has better anti‐jamming performance and controllability compared to the H∞ controller and μ synthesis controller.

Martínez–Kaabar Fractal–Fractional Laplace Transformation with Applications to Integral Equations

This paper addresses the extension of Martinez–Kaabar (MK) fractal–fractional calculus (for simplicity, in this research work, it is referred to as MK calculus) to the field of integral transformations, with applications to some solutions to integral equations. A new notion of Laplace transformation, named MK Laplace transformation, is proposed, which incorporates the MK α,γ-integral operator into classical Laplace transformation. Laplace transformation is very applicable in mathematical physics problems, especially symmetrical problems in physics, which are frequently seen in quantum mechanics. Symmetrical systems and properties can be helpful in applications of Laplace transformations, which can help in providing an effective computational tool for solving such problems. The main properties and results of this transformation are discussed. In addition, the MK Laplace transformation method is constructed and applied to the non-integer-order first- and second-kind Volterra integral equations, which exhibit a fractal effect. Finally, the MK Abel integral equation’s solution is also investigated via this technique.

Fuzzy fractional shallow water wave equations: analysis, convergence of solutions, and comparative study with depth as triangular fuzzy number

Abstract We explore the integration of fuzzy fractional calculus into the modeling framework, recognizing its significance in capturing the inherent uncertainties and complexities present in Shallow Water Wave (ffSWW) dynamics. By incorporating fuzzy fractional calculus, we aim to enhance the accuracy and robustness of ffSWW equations, particularly in representing vague or imprecise parameters such as seabed topography, initial wave conditions, and material properties. In this article, we consider the time derivative as a fractional order instead of the traditional integer order, which allows us to interpret the behavior of the solution for different orders. Further, the sea depth has been considered as a Triangular Fuzzy Number (TFN). We employ the Homotopy Perturbation Transform Method (HPTM) to obtain the solution of ffSWW equations. The convergence of the obtained series solutions has been investigated theoretically and numerically. Also, the acquired results using the current method are validated through the comparison with pre-existing findings concerning integer order. Furthermore, simulation results for various fractional orders, as well as fuzzy lower and upper solutions of depth-averaged velocity and water surface elevation, are provided for triangular fuzzy numbers.

Analytical Model for Heat Transfer Around Energy Piles in Layered Soil With Interfacial Thermal Resistance by Integral Transform Method

ABSTRACTEnergy piles are commonly deployed in vertically layered geological conditions due to the geological structure and pile foundation backfill. The imperfect contact between adjacent soil layers results in resistance to heat transfer at the interface, known as the interfacial thermal resistance effect. In this paper, the energy pile was simplified as a finite‐length solid cylindrical heat source, and an analytical model was established for layered heat transfer of energy piles considering the interfacial thermal resistance effect. The Laplace‐domain solutions to the temperatures in the layered ground were derived by using the finite Hankel and Laplace transforms. The Crump method was subsequently employed to numerically invert Laplace‐domain solutions to the time‐domain solutions. The proposed model was validated by comparing with an analytical solution of a homogeneous model and COMSOL numerical solution. These solutions were used to analyze the temperature response around energy piles considering interfacial thermal resistance. Finally, a parametric study was performed to explore the effects of interfacial thermal resistance and other thermal properties of the soil layer on the layered heat transfer of energy piles.

Implementasi Fast Fourier Transform dalam Penyelesaian Persamaan Difusi Panas Satu Dimensi

The Fast Fourier Transform (FFT) method for solving the 1-D heat diffusion equation offers an efficient approach for resolving partial differential equations (PDEs) with various time steps . FFT is used to transform the 1-D heat diffusion equation into the frequency domain and back to the time domain through inverse FFT. Using mathematical modeling with initial and Dirichlet boundary conditions, the numerical solutions produced by FFT are compared with analytical solutions. The accuracy of the method is validated using MAE and MSE calculated in Matlab. At several time intervals , the obtained MAE and MSE values indicate a good agreement between the numerical and analytical solutions, with very small errors. Numerical stability analysis confirms the reliability of the FFT method across various The variation in time step has a significant impact on the accuracy and stability of the solution. Smaller time steps improve accuracy and stability but require longer computation times. The optimal time step selected in this study is Increasing the number of discretization points also enhances accuracy but implies an increase in computational load and memory usage. The FFT method demonstrates good numerical consistency with increasing

Two-Stage Locating and Capacity Optimization Model for the Ultra-High-Voltage DC Receiving End Considering Carbon Emission Trading and Renewable Energy Time-Series Output Reconstruction

With the load center’s continuous expansion and development of the AC power grid’s scale and construction, the recipient grid under the multi-feed DC environment is facing severe challenges of DC commutation failure and bipolar blocking due to the high strength of AC-DC coupling and the low level of system inertia, which brings many complexities and uncertainties to economic scheduling. In addition, the large-scale grid integration of wind power, photovoltaic, and other intermittent energy sources makes the ultra-high-voltage (UHV) DC channel operation state randomized. The deterministic scenario-based timing power simulation is no longer suitable for the current complex and changeable grid operation state. In this paper, we first start with the description and analysis of the uncertainty in renewable energy (RE) sources, such as wind and solar, and reconstruct the time-sequence power model by using the stochastic differential equation model. Then, a carbon emission trading cost (CET) model is constructed based on the CET mechanism, and the two-stage locating and capacity optimization model for the UHV DC receiving end is proposed under the constraint of dispatch safety and stability. Among them, the first stage starts with the objective of maximizing the carrying capacity of the UHV DC receiving end grid; the second stage checks its dynamic safety under the basic and fault modes according to the results of the first stage and corrects the drop point and capacity of the UHV DC line with the objective of achieving safe and stable UHV DC operation at the lowest economic investment. In addition, the two-stage model innovatively proposes UHV DC relative inertia constraints, peak adjustment margin constraints, transient voltage support constraints under commutation failure conditions, and frequency support constraints under a DC blocking state. In addition, to address the problem that the probabilistic constraints of the scheduling model are difficult to solve, the discrete step-size transformation and convolution sequence operation methods are proposed to transform the chance-constrained planning into mixed-integer linear planning for solving. Finally, the proposed model is validated with a UHV DC channel in 2023, and the results confirm the feasibility and effectiveness of the model.

Transgenic rice with microbial high-temperature-resistant β-glucosidase gene significantly improved 2-acetyl-1-pyrroline content and edible quality.

The content of 2-acetyl-1-pyrroline (2-AP) directly affects the aroma and taste of rice. Δ1-Pyrroline and methylglyoxal are the precursors of 2-AP synthesis, and β-glucosidase plays an important role in the synthesis of methylglyoxal. In this study, β-glucosidase gene cloned from Pyrococcus furiosus was molecularly modified to obtain the high-temperature-resistant β-glucosidase gene 371-β-glucosidase (T371A), which was transformed into kitaake varieties (Oryza sativa L. subsp. japonica) by Agrobacterium-mediated transformation method, and transgenic rice with heterologous expression of T371A was obtained. Experiments were conducted in transgenic rice to investigate whether this gene had an effect on the synthesis of 2-AP. Under the optimum reaction temperature of 50°C and cooking temperature of 100°C, the enzyme activity of β-glucosidase in transgenic rice seeds was prominently increased by 260-280% and 419-426% over that of the control, respectively. The content of 2-AP in transgenic rice seeds significantly increased by 75-105% under normal temperature and high-temperature cooking conditions compared with the control. It was also found that transgenic rice increased the content of methylglyoxal and decreased the expression of betaine aldehyde dehydrogenase (BADH2). The high-temperature-tolerant β-glucosidase gene obtained in this study provides an innovative technical strategy for molecular breeding of high-edible aroma crops and has wide application potential. © 2024 Society of Chemical Industry.

STEWART PLATFORM MULTIDIMENSIONAL TRACKING CONTROL SYSTEM SYNTHESIS

Context. Creating guaranteed competitive motion control systems for complex multidimensional moving objects, including unstable ones, that operate under random controlled and uncontrolled disturbing factors, with minimal design costs, is one of the main requirements for achieving success in this class devices market. Additionally, to meet modern demands for the accuracy of motion control processes along a specified or programmed trajectory, it is essential to synthesize an optimal control system based on experimental data obtained under conditions closely approximating the real operating mode of the test object. Objective. The research presented in this article aims to synthesize an optimal tracking control system for the Stewart platform’s working surface motion, taking into account its multidimensional dynamic model. Method. The article employs a method of a multidimensional tracking control system structural transformation into an equivalent stabilization system for the motion of a multidimensional control object. It also utilizes an algorithm for synthesizing optimal stabilization systems for dynamic objects, whether stable or not, under stationary random external disturbances. The justified algorithm for synthesizing optimal stochastic stabilization systems is constructed using operations such as addition and multiplication of polynomial and fractional-rational matrices, Wiener factorization, Wiener separation of fractional-rational matrices, and the calculation of dispersion integrals. Results. As a result of the conducted research, the problem of defining the concept of analytical design for a Stewart platform’s optimal motion control system has been formalized. The results include the derived transformation equations from the tracking control system to the equivalent stabilization system of the Stewart platform’s working surface motion. Furthermore, the structure and parameters of the main controller transfer function matrix for of this control system have been determined. Conclusions. The justified use of the analytical design concept for the Stewart platform’s working surface optimal motion control system formalizes and significantly simplifies the solution to the problem of synthesizing complex dynamic systems, applying the developed technology presented in [1]. The obtained structure and parameters of the Stewart platform’s working surface motion control system main controller, which is divided into three components W1, W2, and W3, improve the tracking quality of the program signal vector, account for the cross-connections within the Stewart platform, and increase the accuracy of executing the specified trajectory by increasing the degrees of freedom in choosing the controller structure

Research on High Power Density Flyback Converter With a New Passive Lossless Snubber

ABSTRACTThis paper proposes a flyback converter with a new passive lossless snubber. It eliminates the power dissipation of the traditional RCD snubber, while providing protection against MOS breakdown from energy stored in the power‐transformer leakage. This energy is used to power the power chip, which simplifies the design of the transformer. Meanwhile, an optimal design method for high power density planar transformers is presented. Applying the principle of flux cancellation, a matrix transformer that originally needed an independent magnetic core was integrated into a single magnetic core to reduce the volume of the core. This method effectively reduces the printed circuit board (PCB) layer number of the planar transformer and increases the possibility of the application of the planar transformer in the flyback converter. The detailed operation principle and design considerations are presented. Finally, a multi‐output flyback converter with a frequency of 100 kHz is designed to verify the practical performance of the structure.

Digital transformation in Russia: Turning from a service model to ensuring technological sovereignty

The paper outlines core aspects of the digital transformation process in Russia since the early 2000s, as well as recent legislative initiatives and practices at the federal level. It considers the digitalization of public services, efforts towards ‘sovereignization’ of the Russian segment of the Internet, and the current focus on cybersecurity and the development of artificial intelligence. The paper highlights the tendency to strengthen the factor of protection of state interests and national security alongside control over online activities of citizens in comparison with the initial understanding of digital transformation as a human-oriented process aimed at increasing the accessibility and convenience of public services. It can be assumed that this change in the goals and methods of digital transformation is one of the manifestations of a broader political, social and cultural process of separation, primarily from the West, that Russian society is currently undergoing, amidst a growing official narrative of threats from both external and internal forces that require greater independence and increased vigilance, including in the digital domain.

A microscale cellular automaton method for solid-state phase transformation of directed energy deposited Ti6Al4V

Directed energy deposition is a promising additive manufacturing technology that fabricates complex geometries by fusing feed material layer-by-layer. However, the formation mechanism of the directed energy deposited Ti6Al4V solid-state phase transformation process, which is crucial for understanding the process-structure–property relationship, has remained unclear. In this study, a microscale cellular automaton method is proposed to simulate the microstructure evolution process for Ti6Al4V, specifically the β→α/α′ phase transformation process within a few β grains. The method is further integrated with the mesoscale cellular automaton method, which predicts the prior β grain structure, the solid-state phase transformation kinetics model for the prediction of the phase volume fractions, and the finite volume method, which is used for the thermal-fluid flow modelling, providing a temperature field to the former. The integrated numerical framework not only links the thermal history with the phase volume fractions but also provides the columnar β grain structures and acicular α/α′ grain structures in satisfying agreement with the available experimental observation. Moreover, the predictions shed some light on the formation mechanism of the hierarchical α/α′ structure and their particular clusters. The influence of the cooling rate on the α/α′ grain formation is illustrated via the three-layer case simulation. The findings on the formation mechanism of α/α′ are beneficial in tailoring the microstructure of Ti6Al4V for excellent mechanical properties in directed energy deposited Ti6Al4V.

Piezoelectric-enhanced MoS2@PVDF-HFP composite for photocatalytic degradation of tetracycline

In this work, composite films of molybdenum disulfide (MoS2) with poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were fabricated using aqueous phase transformation and hydrothermal methods, aiming at efficiently degrading tetracycline hydrochloride (TC). The findings revealed that the degradation efficiency of TC by MoS2@PVDF-HFP, when subjected to a combined photocatalysis process involving a simulated pressure electric field and aeration, reached a remarkable 96.11% within 1 hour-surpassing the performance observed under individual conditions. The changes in the electron density cloud on the films surface induced by the pressure electric field and the acceleration of electron transfer rate between contact interfaces were evident. Notably, the composite films exhibited a stable performance with a TC removal rate of 90.23% after five cycles, including a relatively stable degree of mineralization. We employed Density Functional Theory (DFT) to investigate the changes in the state density of MoS2@PVDF-HFP under different conditions, such as compressive stress, tension, and no force. This further clarified the mechanism of piezoelectric coupling photocatalysis promoting induced charge transfer on the films surface. The research findings presented in this paper provide a promising avenue for the application of piezoelectric field-assisted photocatalysis in enhancing material performance.