Computational Modeling Methods Research Articles

Analyzing the load for the design elements of the working equipment of the loader with a telescopic boom

Problem. The pace of road construction and reconstruction dictates high requirements for modern equipment, and in most cases the requirements relate to work equipment. When performing technological operations, external loads are transmitted through the main working body to all elements of work equipment, components and parts of the machine as a whole. Methodology. The use of software products makes it possible to preanalyze any combinations of design, modeling, as well as strength studies and strength testing. On the basis of the obtained data, it is possible to analyze the load in the nodes of the metal structure of the working equipment without conducting field tests. The work is a continuation of previous studies using computer modeling methods in the engineering industry. Designing or modernization of technical objects at the moment is impossible without creating three-dimensional models. The purpose of this work is to develop a digital model of the telescopic loader equipment in the "Dynamic Simulation" environment of the Autodesk Inventor software package, to perform research on the kinematics of movement and load modes of individual elements. The use of telescopic working equipment expands the capabilities of front loaders on a wheel base, but in turn, leads to an increase in material costs during design and production. Results. The process of separate scooping of bulk material in a stack is considered, which consists in introducing a bucket into the stack with a progressive movement followed by stopping the loader and turning the bucket. Originality. The main forces acting on the working equipment during the rotation of the bucket and the boom during the scooping process are the gravitational forces of the elements of the working equipment, non-conservative forces arising in the cylindrical surface of the section and the normal force from the side of the wall of the stack of material. Practical value. External loads are applied to the edge of the bucket. Their direction depends on the trajectory of the working equipment and in the process of simulation they changed depending on the current vertical coordinate of the cutting edge of the bucket.

METHODS OF THE FRACTAL APPROACH IN SCIENCE EDUCATION: INNOVATIVE TECHNOLOGY AND CONCEPTS OF COMPUTER MODELING

Formulation of the problem. At the present stage of the development of science education and information technology, their integration, complementarity, and implementation are essential. Therefore, the search for methods of teaching natural sciences, based on the principles of self-organization and computer modeling, corresponds to the immediate tasks of the present. Materials and methods. Methods of comparative analysis, computer modeling, and generalization strategy are used. The study is based on the physics course content and the use of the programming language. Results. An innovative fractal approach to the teaching of physical and mathematical disciplines is proposed as a method of improving independent and creative computer modeling of natural phenomena. The fundamental principles of object-oriented programming (encapsulation, inheritance, polymorphism) have proven to be influential in shaping the physical and mathematical aspects of the information architecture of the perception of educational disciplines. The possibility of using this approach in other sections of physics is demonstrated. The developed iterations of the fractal structure are presented in the example of the study of the "Geometric Optics" and "Wave Optics" sections of physics. It is shown that each iteration is characterized by synergy: the addition of a new iteration provides a high-quality and in-depth perception of new information. Conclusions. The formation of the specified integrated fractal structure conditions the integrity of information perception and its formation happens intuitively. The analysis of the conducted studies confirmed the innovativeness and effectiveness of the fractal approach. This approach can be used to develop systems for the processing and transmission of information, intelligent information materials, and artificial intelligence.

Математическое и компьютерное моделирование колебания системы «груз-балка» козлового крана

Introduction. Gantry grappling cranes are the main equipment for cargo transportation in the technological processes of mining and enrichment of rocks. During the operation of the crane, undesirable effects such as the rocking of the payload occur, which in turn affects the dynamic state of the crane beam. Materials and methods. To solve this problem, methods of mathematical and computer modeling of a system with two degrees of freedom were used. To identify the influence of different combinations of the combination of payload mass and cable length on oscillation frequencies, a computational experiment was carried out and the response surface of the oscillation frequency function was constructed. The natural oscillation frequencies of the beam were determined by the finite element method in the NASTRAN program. Results. The results of mathematical modeling were graphs of changes in the angle of deviation of the cable from the vertical and the movement of the trolley, the response surface of the frequency of oscillation of the payload from the length of the cable and the weight of the cargo. Discussion. A comparison of the simulation results of cargo vibrations and crane beam vibrations showed the proximity of the values of the frequencies of the payload vibrations and the gantry crane design, which justifies the need for further analysis of the frequency response of the crane beam to the disturbance of the payload vibration force. Conclusion. The frequency of vibrations of the load significantly affects the static and vibration strength of the crane beam of the gantry crane Resume. The research results can be useful in the development of technical solutions for the engineering implementation of promising gantry crane designs.

"EXPERIMENTAL STUDIES OF THE DEPENDENCE OF TOOL PERFORMANCE ON DESIGN PARAMETERS"

"The comparative analysis allowed us to consider the equipment for processing solid household waste (SHW), tool designs, to monitor the work processes and come to the conclusion about their low level of resource conservation and not rational wear. There was also a high level of demand for collapsible tools for equipment for processing SHW. A collapsible tool has been designed for equipment for processing SHW, after that an algorithm for calculating the design parameters of the tool was developed, which was included in the tool design program for equipment for processing SHW in Microsoft Office Excel. This program allows you to design a tool model in accordance with the design parameters, technical characteristics of the equipment, needs and capabilities of the activity. The article presents the developed method of computer modeling to determine the optimal design parameters of a tool for equipment for processing SHW, the results of testing 3D models of tools for equipment for processing SHW in different variations. The materials of this work can be used in the educational process as a methodological guide and/or recommendations for computer modeling, analysis and selection of tool designs for recycling equipment. Keywords: SHW recycling, utilization, SHW, solid waste, tool. "

Гибридное технологическое оборудование: к вопросу рационального выбора объектов модернизации при проведении работ, связанных с дооснащением стандартной станочной системы дополнительным концентрированным источником энергии

Introduction. Improving the competitiveness of manufactured products is impossible without achieving high rates of resource and energy saving, while providing modern machine tools with the proper level of production flexibility in combination with guaranteed high values of processing productivity and the required level of parts manufacturing quality. Insufficient or excess capacity of technological equipment leads to a decrease in its economic efficiency, an increase in capital costs and, as a result, an increase in the cost of production. In the machine tool industry, which is a strategically significant and basic industry for the modernization of mechanical engineering, there is a special interest in the development of a new type of technological equipment that makes it possible to implement methods for modifying the surface layers of parts by processing it with concentrated energy sources. The combination of two processing technologies (mechanical and surface-thermal operations) in the conditions of integrated equipment makes it possible to level the shortcomings of monotechnologies and obtain new effects that are unattainable when using technologies separately. Ensuring an optimal level of quality — one of the unconditional requirements of a market economy — is a priority when developing the overall concept of technological equipment. Thus, it should be noted that the required and specific set of consumer properties are laid down during the design. And, therefore, the problem of quality optimization belongs to the field of forecasting and should be comprehensively addressed at the initial stage of developing the concept of technological equipment. The purpose of this research is to rationally choose the objects of modernization when carrying out work related to retrofitting a standard machine tool system with an additional concentrated energy source. Methods: Theoretical studies of the possible structural composition and layout of hybrid equipment during the integration of mechanical and surface-thermal processes were carried out taking into account the main provisions of structural synthesis and components of metal-cutting systems. During the research, issues related to the main provisions of system analysis, the geometric theory of surface formation, the design of metal-cutting equipment, methods of mathematical and computer modeling were raised. Results and discussion. Theoretical studies is found that currently, most of the parameter-oriented (dimension) series of general-purpose metal-cutting machines, built according to the law of geometric progression with a constant denominator, are the cause of multiple duplication of individual size ranges on machines of the same series. This gives grounds to talk about an unreasonable increase in the number of its members and, as a result, to an increase in the cost of designing, manufacturing and operating equipment. The authors adhere to the point of view that in order to ensure maximum efficiency of hybrid metal-cutting equipment, it is necessary to implement a parameter-oriented series built with a variable denominator. Such a principle of forming a parameter-oriented series makes it possible to provide an almost equal probability of processing a surface of any size with maximum productivity with a threefold overlap of ranges. Approbation of the technique for forming the structure of parametric series is carried out. It is theoretically proven that during the operation of vertical milling machines of the operating parameter-oriented series with the denominator φ = 1.26 (GOST 9726-89), there is a multiple overlap of individual size ranges, reaching a ninefold value in a certain range of sizes, which, of course, affects the efficiency of the existing machine tool holding. In turn, when synthesizing a promising parametric series of vertical milling machines with a cross table, it was shown that the new parameter-oriented series has a smaller number of members. Reducing the range of manufactured and modernized machine tools will increase the serial production and reduce current expenses on repairs and maintenance. Moreover, this effect is achieved while maintaining the flexibility of the machine tool holding.

Aluminum Bronze Crystallization on Deformed Base during Electron Beam Additive Manufacturing

To obtain products by using additive manufacturing (AM) methods, it is necessary to take into account the features of the formed internal structure of the material. The internal structure depends on the 3D printing parameters. To predict it, it is effective to use computer modeling methods. For this purpose, using the example of aluminum bronze, the influence of the base structure and heat input during surfacing on the grain structure of the deposited layers was studied. To create numerical models, we used data obtained from electron backscatter diffraction (EBSD) analysis of samples. The heterogeneity of the formation of the structure in each selected zone is established, which indicates the heterogeneity of heat input in local areas of the material in one mode of surfacing. For typical cases of crystallization, modeling using the molecular dynamics (MD) method of crystallization processes with different heat inputs to the base with characteristics specified based on experimental data was carried out. It was established that the amount of heat input determines the degree of melting and the inherited defectiveness of growing crystals. The formation of misorientation boundaries and crystallization centers of new grains is determined by the conditions of joint growth of grains with given crystallographic parameters of the computational model. The grain structure obtained as a result of simulation is consistent with the experimentally observed structure of the samples.

Field studies of a thermoelectric system for thermal action on the anterior segment of the human eyeball

Objective. The aim of the study is to develop the design of a thermoelectric system (TPS) for thermal action on the anterior segment of the human eyeball, as well as to conduct its field studies.Method. The study is based on the methods of thermodynamic analysis, natural and computational modeling of processes and life support facilities.Result. The design of TPP for thermal impact on the anterior segment of the human eyeball is presented. Its fullscale studies were carried out in accordance with the existing methods of thermophysical measurements. Curves of changes in the temperature of the surface of the gelatin model of the human eyeball over time during cooling and heating were obtained for the supply currents of the thermoelectric module (TEM) included in the TPP, equal to 2.5 A, 3 A, 3.5 A, A and 1 A, 1 .2 A, 1.4 A, as well as changes in the temperature of the object of influence over time when changing the cooling mode to heating and vice versa. To assess the possibilities of heat removal from the hot junctions of TEMs in the system, data were obtained on the change in their temperature over time during the cooling effect for various values of the module supply current.Conclusion. It has been established that standard modules produced by domestic firms can be used as TEMs in the system. The duration of entering the TPP mode is about 230 s. The refore, it seems appropriate to bring the TPP to the operating mode before the actual procedures are carried out. It has been established that the duration of TPP switching from cooling to heating mode and vice versa is 230 s, which requires further optimization of the design and operating modes of the device through the use of more advanced types of TEMs and the use of forced operation of thermal modules in the transient mode.

Modeling of regasification and recirculation processes during the transportation of liquefied natural gas

Objective. The purpose of the research is modeling and analysis of technological processes occurring at the transshipment terminal of liquefied natural gas.Method. The study is based on the methods of thermodynamic analysis, full-scale and computational modeling of processes and objects of refrigeration and cryogenic equipment in order to find optimal solutions in terms of efficiency, reliability and service life of low-temperature installations, machines and apparatus.Result. The article describes the operation algorithm of an LNG transshipment terminal and proposes a mathematical apparatus for modeling the technological processes occurring in it. Information about the causes of the formation of LNG vapors (Boil-off gas (BOG)) during its transportation and reloading is presented, methods for utilizing excess LNG vapors are considered.Conclusion. To maintain the cryogenic temperature of the unloading arms, an LNG recirculation line (recirculation pipelines) is provided.

Challenges in two‐scale computational homogenization of mechanical metamaterials

AbstractThanks to the advancement of additive manufacturing technologies, mechanical metamaterials have attracted a great deal of attention in recent years. With the employment of such technologies, materials with exceptional or tailored mechanical properties can be easily manufactured mainly by 3D printing of different microstructures rather than by changing the material composition. These lattice materials can provide remarkable material properties in spite of being significantly lighter than typical bulk materials. Due to the large number of degrees of freedom for engineering structures, single‐scale numerical simulation of such cellular materials is computationally demanding. Therefore, two‐scale computational homogenization approaches, such as FE2 and FE‐FFT, can perform a key role in the cost‐effective numerical modeling of metamaterials. Two‐scale computational homogenization methods rely on solving a boundary value problem (BVP) for each of the macroscopic and microscopic scales in a nested procedure. Although representative homogenization techniques have been widely used to study materials with heterogeneous microstructures, there still exist some challenges in their employment for lattice materials. This study addresses main challenges in two‐scale‐based computational homogenization methods for numerical modeling of mechanical metamaterials. High dependence of convergence rate and accuracy on phase contrast for fast Fourier transform (FFT) solvers and comparable macro and micro characteristic lengths in metamaterials (i.e. the applicability of the principle of scale separation) are some examples of such challenges.

Способ сокращения времени подачи резервного питания в системах электроснабжения с двигательной нагрузкой

Nowadays fast-acting automatic transfer equipment is commonly applied in power supply systems with a motor load since it ensures uninterrupted power supply of critical consumers. However, their application requires the use of high-speed breakers. The implementation of a “high-speed” transfer to a backup power source when using vacuum switches may not be possible due to the long turn-on and turn-off times. Therefore, the purpose of the paper is relevant. The aim of the paper is to study the possibility to reduce the backup power supply time by improving the algorithm to control the vacuum switches of the main and backup power sources in the modes “high-speed” switching by the fast-acting automatic device in case of short circuits in the external power supply network. To achieve this purpose, computer modeling methods are used. They are based on mathematical models of electrical network elements written using systems of differential equations. The authors have defined the regularities of the transient processes in synchronous and induction motors when switching to a backup power source by the fast-acting automatic device in case of short circuits in the external power supply network. It makes possible to set the limit value of the mismatch angle between the residual voltage vectors on the section of the main power source and the voltage of the backup power source, at which the level of the self-starting current does not exceed the values of the starting currents. Also, it makes possible to develop an algorithm to control breakers. The proposed algorithm is based on changing the operation order of the switches of the main and backup power sources. The obtained results show that implementation of the proposed algorithm to control breakers of the main and backup power sources in fast-acting automatic devices in case of short circuits in the external power supply network of the main power source makes it possible to reduce the backup power supply time and decrease the level of self-starting currents that do not exceed the level of starting currents of electric motors without use of high-speed switches.

DFT Calculation and MD Simulation Studies on Gemini Surfactant Corrosion Inhibitor in Acetic Acid Media.

Gemini surfactant corrosion inhibitor (CI) is one type of CI mainly used in mitigating corrosion in the complex system of oil/gas production industries. Computer modeling methods such as density functional theory (DFT) calculation and molecular dynamic (MD) simulation are required to develop new CI molecules focusing on their application condition as a prediction or screening process before the physical empirical assessment. In this work, the adsorption inhibition efficiencies of two monomer surfactants (2B and H) and their respective Gemini structures with the addition of different spacers (alkyl, benzene, ester, ether, and ketone) are investigated using DFT calculation and MD simulation method in 3% sodium chloride (NaCl), and 1500 ppm acetic acid solutions. In DFT calculation, 2B-benzene molecules are assumed to have the most promising inhibition efficiency based on their high reactivity and electron-donating ability at their electron-rich benzene ring region based on the lowest bandgap energy (0.765 eV) and highest HOMO energy value (-2.879 eV), respectively. DFT calculation results correlate with the adsorption energy calculated from MD simulation, where 2B-benzene is also assumed to work better as a CI molecule with the most adsorption strength towards Fe (110) metal with the highest negative adsorption energy value (-1837.33 kJ/mol at temperature 323 K). Further, diffusion coefficient and molecular aggregation analysis in different CI concentrations through MD simulation reveals that only a small amount of Gemini surfactant CI is needed in the inhibition application compared to its respective monomer. Computer simulation methods successfully predict and screen the Gemini surfactant CI molecules that can work better as a corrosion inhibitor in acetic acid media. The amount of Gemini surfactant CI that needs to be used is also predicted. The future planning or way forward from this study will be the development of the most promising Gemini surfactant CI based on the results from DFT calculation and MD simulations.

Quantifying social performance: A review with implications for further work.

Human social performance has been a focus of theory and investigation for more than a century. Attempts to quantify social performance have focused on self-report and non-social performance measures grounded in intelligence-based theories. An expertise framework, when applied to individual differences in social interaction performance, offers novel insights and methods of quantification that could address limitations of prior approaches. The purposes of this review are 3-fold. First, to define the central concepts related to individual differences in social performance, with a particular focus on the intelligence-based framework that has dominated the field. Second, to make an argument for a revised conceptualization of individual differences in social-emotional performance as a social expertise. In support of this second aim, the putative components of a social-emotional expertise and the potential means for their assessment will be outlined. To end, the implications of an expertise-based conceptual framework for the application of computational modeling approaches in this area will be discussed. Taken together, expertise theory and computational modeling methods have the potential to advance quantitative assessment of social interaction performance.

Impact of organic dye-photosensitizer on TiO2 nanocrystalline surface for high performance organic electronic devices: A computational insight

Using computational modelling methods as density functional theory (DFT) and time-dependent density functional theory (TD-DFT), the optoelectronic properties of different compounds from Thiophene-Cyanoacrylic-Acid derivatives have been performed for organic electronic devices. New challenges in specific properties of organic-π-conjugated system of Thiophene-Cyanoacrylic-Acid derivatives are of great significance since they have become the most encouraging for the organic electronic device technology such as solar cells. The use of electronic excitations and reorganization energies (λ) are viable methods for increasing its efficiency and enhanced harvesting of the solar spectrum. Different Donor parts are anchoring to the Thiophene-Cyanoacrylic-Acid Acceptor part for their high electron extraction to semi-conductor devices. The impact of Acceptor parts in each π-conjugated systems, were investigated in their isolated form as well as upon adsorption on TiO2 cluster surface in chelating state [dye-(TiO2)16]. For the three series of dyes studied in this investigation: D–A–π–A, D–π–π–A and D–A-π–π–A, the adsorptions were effective on the TiO2 surface. The calculated results suggest that the HOMO-LUMO energy gap (ΔEgap), ionization potential (IP), electron affinity (EA), reorganization energies (electron and hole) (λ), open-circuit voltage (Voc), fill factor (FF), short-circuit current density (Jsc), light-harvesting efficiency (LHE), dye regeneration driving force (ΔGregn), electron injection driving force (ΔGinjec), and density of state (DOS) are affected by Acceptor introducing groups in different Thiophene-Cyanoacrylic-Acid Derivatives. Moreover, our investigation shows that these considered novel optoelectronic Photosensitizer dyes can exhibit enhanced organic electronic parameters and are fitting candidates for preparation of high-performance charge-transport materials.

Structural Optimized Design of a Powder Mixer for Multi-Material Directed Energy Deposition Based on CFD-DPM

Directed energy deposition (DED) offers an unprecedentedly convenient and efficient additive manufacturing approach to novel alloy designs such as high entropy alloys. As a critical component of the novel DED system, a powder mixer to stably and uniformly mix different powders plays an important role in the DED process. In this paper, the computational fluid dynamics-discrete phase model (CFD-DPM) method was used to simulate the characteristics of the gas-solid coupled fluid inside the powder mixer. The influence of the structural details of the powder mixer on the motion characteristics of the gas-solid coupled fluid was investigated by numerical simulation. Based on the numerical simulation results, the range of parameters of critical structure such as the inlet angle, the diameter and height mixing chamber, and the height of the bottom was determined. The difference in powder mixing uniformity among different powder mixers was qualitatively analyzed through powder mixing experiments. The BSE-EDS results of mixed powder samples show that the mixer with reasonable structural parameters has better mixing uniformity. In summary, this work provides a powerful reference for the rapid optimization design of the powder mixer structure.

TO THE CALCULATION OF RING PLATES ON A VARIABLE ELASTIC BASE

The article examines the bending of ring plates on a variable elastic base. There are different models of elastic base. The simplest is the Winkler model, or the spring model. For beams on a constant elastic base, this model allows obtaining an exact solution, but not for slabs. The case is even more complicated when the elastic basis is variable. There is no single approach to building a universal analytical solution. Therefore, numerical calculation methods are used in engineering practice. The analytical method of direct integration and computer modeling in PC LIRA-CAD with subsequent calculations by the method of finite elements are used. Two examples are considered: a steel plate, which is rigidly clamped along the inner contour, and its outer contour is hinged, and a concrete slab, which is rigidly clamped along the outer contour, and its inner contour is hinged. The results of the numerical implementation show that the values of deflections when calculated by the author's method and the method of finite elements in PC LIRA-CAD practically coincide, and the difference in the values of bending moments reaches 10%. Moreover, the difference in deflections is manifested only in the fourth (and sometimes in the fifth) sign after the comma. It is noted that the method of direct integration demonstrated very high accuracy when solving numerous test problems that have an exact solution. The authors explain the discrepancy in the values of the bending moments obtained here by the semi-automatic breakdown of the finite-element mesh in PC LIRA-CAD. This statement is based on the fact that when the mesh is thickened in the circumferential direction, the results obtained by the two methods for determining the radial and circumferential bending moments are substantially converged.

STRATEGIC MANAGEMENT OF THE PORTFOLIO OF FINANCIAL ASSET

Until now, three approaches to asset portfolio management have been used. The first approach is the classic one, based on the "Efficient Market Hypothesis" (EMH). The second and more modern approach is related to the "Fractal Market Hypothesis" (FMH). Modern economic practice is characterized by the presence of structurally unstable markets, included as nodes in the network of the world economy, which functions in real time. The structure of the available financial instruments is heterogeneous and non-Markovian processes arise in them. The third approach is the formation of a dynamic strategy of investment management of the asset portfolio. Due to the complex structure of the modern global financial market, the heterogeneous structure of available financial instruments and traders using different approaches and time horizons, forecasts, as a rule, require a large number of observations, work poorly at the edges of bifurcations, and do not have a computer model that could build forecasts in real time. In these structures, slow diffusion-type processes with a memory phenomenon occur, i.e., non-Markovian processes. Therefore, the formation of a dynamic strategy using modern methods of mathematical and computer modeling is very promising.
 Real financial data is expressed in rational numbers. Computational models were developed on the basis of classical substance analysis. Therefore, p-adic analysis methods are increasingly used in financial mathematical modeling. These methods are used, in particular, in the construction of neural networks, cellular automata, and percolation models. The paper seems to have taken the first step towards building a "synthetic" model of dynamic asset portfolio management. The model has the form of a differential equation in fractional derivatives obtained using the so-called interbasin kinetics method. A general form of the energy market model is also offered, as one of the specific, especially nowadays, markets.

A refreshing perspective on electrochromic materials: Phenoxazine as an opportune moiety towards stable and efficient electrochromic polyimides

In our attempt to develop appealing EC materials, here we address the electrochromic materials field by employing the aryl-substituted phenoxazine (POZ) as a new member of triarylamine family with excellent potential for electrochromic applications. Thus, a simple synthetic strategy was followed to build a novel POZ-based diamine that was further used in polycondensation reaction with commercially available aromatic dianhydrides to develop three novel polyimides (PIs). Complementarily, POZ-based model compounds were synthesized to get insights into the electrochemical and electrochromic behavior of the synthesized PIs. With the support of the computational quantum mechanical modeling methods (Density-Functional Theory – DFT and Time-Dependent (TD)–DFT), the mechanism responsible for the absence of the dimerization process upon POZ oxidation was established. Without resorting to any structural modification to block the para position of POZ, the present PIs demonstrated exquisite electrochemical and electrochromic performance, including high redox stability during 100 repetitive cyclic voltammetry scans, unique deep-purple coloration during oxidation, high optical contrast, up to 62%, response time below 6.5 s for coloring and 5.1 s for bleaching, excellent electrochromic efficiency, up to 193 cm2/C and a maximum 21% decay of the electrochromic efficiency after 500 cycles. The most efficient EC polyimide was used as an active layer in electrochromic prototype devices to survey the full applicative potential of these PIs. The devices rendered an optical contrast of 51%, 7.9 s for coloring, and 7.2 s for bleaching, electrochromic efficiency of 178 cm2/C, and decay of the electrochromic efficiency of 6.1% after 100 cycles, placing for the first time the POZ-based PIs among the perspective electrochromic materials.

Study of the melting temperature baric dependence for Au, Pt, Nb

In this work we present new analytical (i.e., without computer modeling) method for calculating the dependence of the melting temperature (Tm) on pressure (P) for a single-component crystal. The method is based on the paired four–parameter Mie–Lennard-Jones interatomic interaction potential, and the delocalized criterion of melting. This method was used to calculate the baric dependences of the melting temperature Tm(P) and its pressure derivative Tm′(P) for gold, platinum and niobium in the pressure range: P = 0–1000 GPa. It has been shown that the dependences calculated by this method for gold and platinum are in better agreement with experimental data than the dependences obtained by computer modeling methods: the molecular dynamics simulations and the ab initio Z-method calculations. For niobium, the calculated Tm(P) dependence turned out to be steeper, i.e. the Tm′(P) values turned out to be greater than the experimental data obtained in [D. Errandonea et al. Communications Materials 1, 1 (2020)]. It has been indicated that this deviation can be caused both by a decrease in the Lindemann parameter with an increase in pressure, and by the redistribution of electrons in the s-to-d orbitals during compression of transition metals with a bcc structure. Furthermore, the discrepancy may also be due to the highly-correlated chain-like self-diffusion, which is inherent in bcc metals before melting.

Abstract 3111: The Sygnature CHARMD platform - combinatorial high-throughput assembly and review of molecular degraders

Abstract Recent interest the ability to degrade oncogenic proteins has grown exponentially, and the advent of Protein-Targeting Chimeras (PROTACs) has allowed many previously undruggable targets to be specifically targeted. However, the successful development of these bioavailable heterobifunctional degraders relies on the identification of a combination of ligase recruiter, linker and exit vector that allow formation of a competent ternary complex and target degradation. To this end, conventional single-compound synthesis is time-consuming and poses challenges for selection of degrader components with predictive SAR and ADME properties of the assembled bifunctional compound. Here, we demonstrate a high-throughput integrated platform for generation and assessment of bifunctional degraders, incorporating combinatorial chemistry using both commercial and bespoke linkers, cell-based activity assays, and assessment of in vitro DMPK properties (lipophilicity, metabolic stability and experimental polar surface area). Alongside this, we have in place computational methods for ternary complex modelling, linker design and PROTAC prioritisation. Altogether, our approach facilitates rapid screening and identification of bifunctional lead compounds for challenging oncology targets with the potential to deliver significant patient benefit. Our platform approach has been exemplified through application to oncology targets of significant current interests and our results in this area will be highlighted. Citation Format: Roland Hjerpe, Louise Birch, Alex Brien, Lola Cusin, Lorna Duffy, Benoit Gourdet, Rachel Lawrence, Philip MacFaul, Hannah Mortlock, Hannah Neal, Christopher Pearce, Erica Pitti, Gonzalo Robles, Edith Rodrigues, Catriona Scott, Rajesh Singh, Stuart Thomson, Yujia Zhang, Allan Jordan. The Sygnature CHARMD platform - combinatorial high-throughput assembly and review of molecular degraders [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3111.

A hybrid model- and deep learning-based framework for functional lung image synthesis from multi-inflation CT and hyperpolarized gas MRI.

Hyperpolarized gas MRI is a functional lung imaging modality capable of visualizing regional lung ventilation with exceptional detail within a single breath. However, this modality requires specialized equipment and exogenous contrast, which limits widespread clinical adoption. CT ventilation imaging employs various metrics to model regional ventilation from non-contrast CT scans acquired at multiple inflation levels and has demonstrated moderate spatial correlation with hyperpolarized gas MRI. Recently, deep learning (DL)-based methods, utilizing convolutional neural networks (CNNs), have been leveraged for image synthesis applications. Hybrid approaches integrating computational modeling and data-driven methods have been utilized in cases where datasets are limited with the added benefit of maintaining physiological plausibility. To develop and evaluate a multi-channel DL-based method that combines modeling and data-driven approaches to synthesize hyperpolarized gas MRI lung ventilation scans from multi-inflation, non-contrast CT and quantitatively compare these synthetic ventilation scans to conventional CT ventilation modeling. In this study, we propose a hybrid DL configuration that integrates model- and data-driven methods to synthesize hyperpolarized gas MRI lung ventilation scans from a combination of non-contrast, multi-inflation CT and CT ventilation modeling. We used a diverse dataset comprising paired inspiratory and expiratory CT and helium-3 hyperpolarized gas MRI for 47 participants with a range of pulmonary pathologies. We performed six-fold cross-validation on the dataset and evaluated the spatial correlation between the synthetic ventilation and real hyperpolarized gas MRI scans; the proposed hybrid framework was compared to conventional CT ventilation modeling and other non-hybrid DL configurations. Synthetic ventilation scans were evaluated using voxel-wise evaluation metrics such as Spearman's correlation and mean square error (MSE), in addition to clinical biomarkers of lung function such as the ventilated lung percentage (VLP). Furthermore, regional localization of ventilated and defect lung regions was assessed via the Dice similarity coefficient (DSC). We showed that the proposed hybrid framework is capable of accurately replicating ventilation defects seen in the real hyperpolarized gas MRI scans, achieving a voxel-wise Spearman's correlation of 0.57±0.17 and an MSE of 0.017±0.01. The hybrid framework significantly outperformed CT ventilation modeling alone and all other DL configurations using Spearman's correlation. The proposed framework was capable of generating clinically relevant metrics such as the VLP without manual intervention, resulting in a Bland-Altman bias of 3.04%, significantly outperforming CT ventilation modeling. Relative to CT ventilation modeling, the hybrid framework yielded significantly more accurate delineations of ventilated and defect lung regions, achieving a DSC of 0.95 and 0.48 for ventilated and defect regions, respectively. The ability to generate realistic synthetic ventilation scans from CT has implications for several clinical applications, including functional lung avoidance radiotherapy and treatment response mapping. CT is an integral part of almost every clinical lung imaging workflow and hence is readily available for most patients; therefore, synthetic ventilation from non-contrast CT can provide patients with wider access to ventilation imaging worldwide.