Reference System Research Articles

Exergy and thermoeconomic analysis of a novel polygeneration system based on gasification and power-to-x strategy

This study introduces a novel polygeneration system that integrates biomass gasification, anaerobic digestion, photovoltaic (PV) energy, and electrolysis to enhance system flexibility and efficiency. The system includes an allothermal gasification unit that processes lignocellulosic biomass sourced from a botanical garden. The gasifying agent, either steam or oxygen, is supplied by an alkaline electrolyzer, which operates under a Power-to-X strategy, utilizing surplus energy from a PV field. The resulting syngas and hydrogen are blended with biogas from an anaerobic digester, which treats municipal waste, to power a cogenerator. This cogenerator meets the electricity, heating, and cooling demands of a hospital, while the PV field powers the botanical garden. The systems components are modeled using various tools and integrated into the TRNSYS environment for dynamic simulation. An exergy analysis identifies the main sources of exergy destruction, while a thermo-economic analysis evaluates the energy, environmental, and economic impacts of a demonstration plant located in Bogotá’s Botanical Garden. Simulation results show that the system achieves an overall exergy efficiency of around 35 %, with a 96 % reduction in primary energy consumption compared to a reference system, avoiding nearly 6000 tons of CO2 emissions annually. From an economic perspective, the system is profitable, with a payback period of 3.02 years and a Net Present Value of $15.23 million, almost double the capital cost. The gasification unit's exergy efficiency is significantly higher when using oxygen (0.50) compared to steam (0.25), underscoring the importance of integrating electrolysis for improved biomass conversion. The alkaline electrolyzer operates efficiently within its optimal range, with an energy efficiency close to 0.70 and an exergy efficiency around 0.60, effectively utilizing 25 % of the total PV production.

Laws of conservation of mass and momentum for an ideal fluid in the inertial framework of special relativity

In the realm of Newtonian fluids, fundamental conservation laws such as those governing mass, momentum, and energy are rigorously upheld within absolute reference frames. However, within the framework of special relativity and the concept of space -time, the notions of separate conservation of mass and momentum no longer hold. Instead, the theory relies on Lorentz transformations and relative reference systems, typically denoted as S and S', moving uniformly relative to each other, each with its own temporal framework. Within the context of special relativity, particularly in the study of particles, significant findings pertain to the energy-momentum vector. These findings underscore the necessity, when studying fluids within inertial frames, to apply conservation principles to the energy-momentum tensor.

Diblock Rings as Topological Adhesives at Immiscible Polymer Interfaces.

Disparate polymers often do not mix well, and the resulting immiscible interfaces are mechanically weaker than the bulk, which is undesirable for many technological applications. Large-scale molecular simulations are performed to demonstrate the effectiveness of diblock ring polymers as a new type of adhesive for immiscible polymer interfaces. The peak stress σp and the failure strain γp upon shear deformation approach the bulk values with increasing diblock ring length and coverage. Breaking the diblock rings into pairs of diblock linear chains creates a reference system for comparison. The diblock rings increase both σp and γp compared to the diblock linear chains at the same coverage. Further topological analysis based on the Gauss Linking Number reveals that the threading of diblock rings by linear chains from the two opposite sides is the key mechanism for stronger adhesion, which is analogous to the hook-and-loop process in Velcro tape.

Application of a Real-Time Field-Programmable Gate Array-Based Image-Processing System for Crop Monitoring in Precision Agriculture

Precision agriculture (PA) technologies combined with remote sensors, GPS, and GIS are transforming the agricultural industry while promoting sustainable farming practices with the ability to optimize resource utilization and minimize environmental impact. However, their implementation faces challenges such as high computational costs, complexity, low image resolution, and limited GPS accuracy. These issues hinder timely delivery of prescription maps and impede farmers’ ability to make effective, on-the-spot decisions regarding farm management, especially in stress-sensitive crops. Therefore, this study proposes field programmable gate array (FPGA)-based hardware solutions and real-time kinematic GPS (RTK-GPS) to develop a real-time crop-monitoring system that can address the limitations of current PA technologies. Our proposed system uses high-accuracy RTK and real-time FPGA-based image-processing (RFIP) devices for data collection, geotagging real-time field data via Python and a camera. The acquired images are processed to extract metadata then visualized as a heat map on Google Maps, indicating green area intensity based on romaine lettuce leafage. The RFIP system showed a strong correlation (R2 = 0.9566) with a reference system and performed well in field tests, providing a Lin’s concordance correlation coefficient (CCC) of 0.8292. This study demonstrates the potential of the developed system to address current PA limitations by providing real-time, accurate data for immediate decision making. In the future, this proposed system will be integrated with autonomous farm equipment to further enhance sustainable farming practices, including real-time crop health monitoring, yield assessment, and crop disease detection.

Evaluation of the geometric and dosimetric accuracies of deformable image registration of targets and critical organs in prostate CBCT-guided adaptive radiotherapy.

Kilovoltage cone beam computed tomography (kVCBCT)-guided adaptive radiation therapy (ART) uses daily deformed CT (dCT), which is generated automatically through deformable registration methods. These registration methods may perform poorly in reproducing volumes of the target organ, rectum, and bladder during treatment. We analyzed the registration errors between the daily kVCBCTs and corresponding dCTs for these organs using the default optical flow algorithm and two registration procedures. We validated the effectiveness of these registration methods in replicating the geometry for dose calculation on kVCBCT for ART. We evaluated three deformable image registration (DIR) methods to assess their registration accuracy and dose calculation effeciency in mapping target and critical organs. The DIR methods include (1) default intensity-based deformable registration, (2) hybrid deformable registration, and (3) a two-step deformable registration process. Each technique was applied to a computerized imaging reference system (CIRS) phantom (Model 062M) and to five patients who received volumetric modulated arc therapy to the prostate. Registration accuracy was assessed using the 95% Hausdorff distance (HD95) and Dice similarity coefficient (DSC), and each method was compared with the intensity-based registration method. The improvement in the dCT image quality of the CIRS phantom and five patients was assessed by comparing dCT with kVCBCT. Image quality quantitative metrics for the phantom included the signal-to-noise ratio (SNR), uniformity, and contrast-to-noise ratio (CNR), whereas those for the patients included the mean absolute error (MAE), mean error, peak signal-to-noise ratio (PSNR), and structural similarity index measure (SSIM). To determine dose metric differences, we used a dose-volume histogram (DVH) and 3.0%/0.3mm gamma analysis to compare planning computed tomography (pCT) and kVCBCT recalculations with restimulated CT images used as a reference. The dCT images generated by the hybrid (dCTH) and two-step (dCTC) registration methods resulted in significant improvements compared to kVCBCT in the phantom model. Specifically, the SNR improved by 107% and 107.2%, the uniformity improved by 90% and 75%, and the CNR improved by 212.2% and 225.6 for dCTH and dCTC methods, respectively. For the patient images, the MAEs improved by 98% and 94%, the PSNRs improved by 16.3% and 22.9%, and the SSIMs improved by 1% and 1% in the dCTH and dCTC methods, respectively. For the geometric evaluation, only the two-step registration method improved registration accuracy. The dCTH method yielded an average HD95 of 12mm and average DSC of 0.73, whereas dCTC yielded an average HD95 of 2.9mm and average DSC of 0.902. The DVH showed that the dCTC-based dose calculations differed by <2% from the expected results for treatment targets and volumes of organs at risk. Additionally, gamma indices for dCTC-based treatment plans were >95% at all points, whereas they were <95% for kVCBCT-based treatment plans. The two-step registration method outperforms the intensity-based and hybrid registration methods. While the hybrid and two-step-based methods improved the image quality of kVCBCT in a linear accelerator, only the two-step method improved the registration accuracy of the corresponding structures among the pCT and kVCBCT datasets. A two-step registration process is recommended for applying kVCBCT to ART, which achieves better registration accuracy for local and global image structures. This method appears to be beneficial for radiotherapy dose calculation in patients with pelvic cancer.

Development of Surface EMG for Gait Analysis and Rehabilitation of Hemiparetic Patients.

The quantification of electromyographic activity using surface electrodes is invaluable for understanding gait disorders in patients with central nervous system lesions. We propose to evaluate a commercially available low-cost system compared to a reference system in participants with stroke-related movement disorders in functional situations. Three hemiparetic participants performed three functional tasks: two treadmill walks at different speeds and a sit-to-stand test. The vastus lateralis and gastrocnemius medialis muscles were equipped with two EMG sensors. The comparison between the two EMG systems was based on 883 identified cycles. Spearman's correlation coefficients (SCs), linear correlation coefficients (LCCs), and cross-correlation coefficients (CCCs) were calculated. The main results indicate good to very good similarity of the EMG signals collected from the two tested sEMG systems. In the comfortable-walking condition, an SC of 0.894 ± 0.091 and an LCC of 0.909 ± 0.094 were noted. In the fast-walking condition, an SC of 0.918 ± 0.064 and an LCC of 0.935 ± 0.056 were observed. For the 1 min sit-to-stand test, an SC of 0.880 ± 0.058 and an LCC of 0.881 ± 0.065 were noted. This study demonstrates good to very good similarity between the two sEMG systems, enabling the analysis of muscle activity during functional tasks.

Analysis of Current Trends in the Dynamics of Material Damage from Emergencies in the Southern Federal District and Its Regions

The dialectic of the development of socio-economic objects includes the periodic occurrence in the process of such development of various emergency situations (emergencies), perceived by society as random phenomena with very severe economic consequences. Such a random nature makes it difficult to perceive them as specific processes, as well as their economic assessment, as well as the development of measures to prevent and reduce negative consequences. The article reflects a study on the use of statistical data to identify trends in the development of emergency situations and the severity of their economic consequences in the Southern Federal District of Russia. She presents the opportunities that open up for emergency management bodies and also makes outlines for the creation of a methodology for working with statistical data that could be used to create a special information and reference system for information support of the emergency management process. Such a process approach makes it possible to understand trends, give them an economic interpretation, as well as develop effective ways to prevent the occurrence and mitigate overcoming. So far, such scientific and information tools are not actively used in practice, although with their application it would be possible to have a complex, dynamically developing picture.

Realistic 3D Simulators for Automotive: A Review of Main Applications and Features.

Recent advancements in vehicle technology have stimulated innovation across the automotive sector, from Advanced Driver Assistance Systems (ADAS) to autonomous driving and motorsport applications. Modern vehicles, equipped with sensors for perception, localization, navigation, and actuators for autonomous driving, generate vast amounts of data used for training and evaluating autonomous systems. Real-world testing is essential for validation but is complex, expensive, and time-intensive, requiring multiple vehicles and reference systems. To address these challenges, computer graphics-based simulators offer a compelling solution by providing high-fidelity 3D environments to simulate vehicles and road users. These simulators are crucial for developing, validating, and testing ADAS, autonomous driving systems, and cooperative driving systems, and enhancing vehicle performance and driver training in motorsport. This paper reviews computer graphics-based simulators tailored for automotive applications. It begins with an overview of their applications and analyzes their key features. Additionally, this paper compares five open-source (CARLA, AirSim, LGSVL, AWSIM, and DeepDrive) and ten commercial simulators. Our findings indicate that open-source simulators are best for the research community, offering realistic 3D environments, multiple sensor support, APIs, co-simulation, and community support. Conversely, commercial simulators, while less extensible, provide a broader set of features and solutions.

GAM4water: An R-based method for extracting wetted areas from remotely-sensed images

We present ‘GAM4water,’ a R-based method to classify wetted and non-wetted (dry) areas using remotely sensed image indices derived from such images. The GAM4water classification algorithm is built around a Generalized Additive Model (GAM) capable of accounting for non-linear responses. GAM4water can use any type of radiometric data, whether from drones, satellites or other platforms, and can be used with data of different spatial resolutions, geographic extents and spatial reference systems. It is a supervised tool that uses pixel information to distinguish between wetted and dry areas within an image set, extract them and produce a rich output that includes a binary raster, polygons of wetted areas, and a classification performance report. We tested the method in two case-studies, one using high resolution drone images and another using satellite images. The tests show that GAM4water can produce highly accurate classifications of wetted and non-wetted areas, and has the additional benefit of being easily customizable and not requiring complex implementation procedures.•This paper introduces the first R based method of wetted area extraction for remotely-sensed images.•The method is based on Generalized Additive Models and is applicable to any remotely-sensed data.

Analysis of legislative basis for medical rehabilitation in Russia

Background. In recent years, there have been significant changes in the regulatory documentation related to medical rehabilitation, caused by the need to consolidate the principles for rehabilitation of patients in post-COVID period and standardize the procedures used for it. Therefore, it is important to analyze the existing regulatory framework and the proposed changes that will come into force in the near future.Objective: to assess the regulatory legal acts governing the provision of medical rehabilitation in Russia.Material and methods. Regulatory legal acts and their drafts were obtained through the reference and legal systems “Kontur Standard”, “ConsultantPlus”, and the Federal Portal of Draft Regulatory Legal Acts. The following electronic libraries, databases and other sources were used to collect secondary information: eLibrary, Google Scholar, PubMed/MEDLINE, Yandex and social networks.Results. Article 41 of the Constitution of the Russian Federation guarantees the right to health protection and medical care. Within the latter the use of medical rehabilitation can be considered. Going down to the next level, the term “medical rehabilitation” is found in Federal Law dated November 27, 2011 No. 323-FZ “On the fundamentals of health protection of citizens in the Russian Federation”. However, the requirements in the field under consideration are specifically described in Orders of the Ministry of Health of Russia No. 788n and 878n, which establish a three-stage provision of medical rehabilitation and give specific time instructions for the frequency and duration of care prcedures. The conditions for the transition of patients between the stages of medical rehabilitation are presented, and creating interdisciplinary rehabilitation teams is specified.Conclusion. The analysis of innovations in the regulatory framework showed no fundamental changes in the regulation of medical rehabilitation. At the moment, there is a need to expand it by regulating the activities of multidisciplinary rehabilitation teams. A more detailed elaboration of normative documentation regulating the provision of medical rehabilitation to children is necessary.

IoT-Based Wireless System for Gait Kinetics Monitoring in Multi-Device Therapeutic Interventions.

This study presents an IoT-based gait analysis system employing insole pressure sensors to assess gait kinetics. The system integrates piezoresistive sensors within a left foot insole, with data acquisition managed using an ESP32 board that communicates via Wi-Fi through an MQTT IoT framework. In this initial protocol study, we conducted a comparative analysis using the Zeno system, supported by PKMAS as the gold standard, to explore the correlation and agreement of data obtained from the insole system. Four volunteers (two males and two females, aged 24-28, without gait disorders) participated by walking along a 10 m Zeno system path, equipped with pressure sensors, while wearing the insole system. Vertical ground reaction force (vGRF) data were collected over four gait cycles. The preliminary results indicated a strong positive correlation (r = 0.87) between the insole and the reference system measurements. A Bland-Altman analysis further demonstrated a mean difference of approximately (0.011) between the two systems, suggesting a minimal yet significant bias. These findings suggest that piezoresistive sensors may offer a promising and cost-effective solution for gait disorder assessment and monitoring. However, operational factors such as high temperatures and sensor placement within the footwear can introduce noise or unwanted signal activation. The communication framework proved functional and reliable during this protocol, with plans for future expansion to multi-device applications. It is important to note that additional validation studies with larger sample sizes are required to confirm the system's reliability and robustness for clinical and research applications.

Development of a reliable adaptive estimation approach for a low‐cost attitude and heading reference system

AbstractA main challenge within inertial navigation systems involves attitude determination, which refers to the process of estimating the angles that define orientations. A new algorithm is presented to estimate a reliable and proper model for a low‐cost attitude and heading reference system (AHRS), while also, including long‐term global navigation satellite system (GNSS) outages with various dynamical manoeuvres. In the proposed approach, the initial AHRS model is continuously refined at each time step through the incorporation of complementary terms using a new prediction method. These complementary terms are determined using attitude information from the accelerometers output and the GNSS as reference systems. The proposed estimation technique undergoes mathematical analysis to ascertain stochastic stability and is further assessed through real‐world aerial experimental tests conducted with hardware‐in‐the‐loop mechanisation. The obtained results demonstrate a significant enhancement in the reliability and accuracy of the AHRS through the proposed estimation algorithm, even under GNSS blockages. The comparative results highlight the higher performance of the suggested data fusion scheme in providing a reliable and accurate model for the AHRS in normal conditions and assisting a powerful neural network‐based algorithm to provide reliable heading information even during long‐term GNSS outages under dynamical manoeuvres.

Analytical Performance of the FreeStyle Libre 2 Glucose Sensor in Healthy Male Adults.

Continuous Glucose Monitoring (CGM) not only can be used for glycemic control in chronic diseases (e.g., diabetes), but is increasingly being utilized by individuals and athletes to monitor fluctuations in training and everyday life. However, it is not clear how accurately CGM reflects plasma glucose concentration in a healthy population in the absence of chronic diseases. In an oral glucose tolerance test (OGTT) with forty-four healthy male subjects (25.5 ± 4.5 years), the interstitial fluid glucose (ISFG) concentration obtained by a CGM sensor was compared against finger-prick capillary plasma glucose (CPG) concentration at fasting baseline (T0) and 30 (T30), 60 (T60), 90 (T90), and 120 (T120) min post OGTT to investigate differences in measurement accuracy. The overall mean absolute relative difference (MARD) was 12.9% (95%-CI: 11.8-14.0%). Approximately 100% of the ISFG values were within zones A and B in the Consensus Error Grid, indicating clinical accuracy. A paired t-test revealed statistically significant differences between CPG and ISFG at all time points (T0: 97.3 mg/dL vs. 89.7 mg/dL, T30: 159.9 mg/dL vs. 144.3 mg/dL, T60: 134.8 mg/dL vs. 126.2 mg/dL, T90: 113.7 mg/dL vs. 99.3 mg/dL, and T120: 91.8 mg/dL vs. 82.6 mg/dL; p < 0.001) with medium to large effect sizes (d = 0.57-1.02) and with ISFG systematically under-reporting the reference system CPG. CGM sensors provide a convenient and reliable method for monitoring blood glucose in the everyday lives of healthy adults. Nonetheless, their use in clinical settings wherein implications are drawn from CGM readings should be handled carefully.

Numerical analysis of the complete active-space extended Koopmans's theorem.

We investigate the numerical accuracy of the extended Koopmans's theorem (EKT) in reproducing the full configuration interaction (FCI) and complete active-space configuration interaction (CAS-CI) ionization energies (IEs) of atomic and molecular systems calculated as the difference between the energies of N and (N - 1) electron states. In particular, we study the convergence of the EKT IEs to their exact values as the basis set and the active space sizes vary. We find that the first FCI EKT IEs approach their exact counterparts as the basis set size increases. However, increasing the basis set or the active space sizes does not always lead to more accurate CAS-CI EKT IEs. Our investigation supports the observation of Davidson et al. [J. Chem. Phys. 155, 051102 (2021)] that the FCI EKT IEs can be systematically improved with arbitrary numerical accuracy by supplementing the basis set with diffuse functions of appropriate symmetry, which allow the detached electron to travel far away from the reference system. By changing the exponent and the center of the diffuse functions, our results delineate a complex pattern for the CAS-CI EKT IE of LiH, which can be important for the spectroscopic studies of small molecules.

Comparison of the Energy Efficiency of Fixed and Tracking Home Photovoltaic Systems in Northern Poland

The relevance of the article’s results lies in presenting the actual energy yields of PV panels of various generations and types of installations. The aim of the article is to provide answers about the effective operation of three different photovoltaic systems: a stationary off-grid system operated for several years, a stationary on-grid system, and a system mounted on trackers. A stationary on-grid system was used as the reference system, taking its area and energy yield as the reference point. The assessment was made on the basis of energy and cost efficiency analysis using the comparative method. The obtained results were compared to the results of other PV systems whose parameters were obtained from literature analysis. The analysis showed significant differences in adapting them to different sunlight conditions. The results confirmed the validity of using fixed PV panels (Installation II) in the short term and the advantage of the PV panel tracking system (Installation III) in the long term. The results also confirm that Installation I, despite its eight years of operation time, shows a relatively small decrease in efficiency, which confirms the validity of the long-term operation of the PV installation.

Выбор элемента(ов) прототипа модели медицинской организации в целях оптимизации процессов регионального проекта с использованием методов динамического программирования.

Changes in federal legislation regulating the provision of patients suffering from cardiovascular diseases initiate a revision of the regional legislation, and inevitably raises questions of practical adaptation and optimization of the processes of ongoing projects, taking into account resources in the established management model in medical organizations. Finding elements of a prototype model of a medical organization implementing a regional project as objects of influence for theoretical proof of hypotheses using the dynamic programming method (callback function, recursion) is the task of optimizing the project processes considered in this article. The purposeof the research question was to optimize the processes of a regional project using the dynamic programming method, which is focused on finding the objective function F(i) – the number of ways to return the function. The subgoal was to justify the use of dynamic programming methods. Materials and methods. The information base for the study was federal and regional regulatory legal acts published in the legislative reference and legal systems of the Russian Federation, and electronic resources. The study was carried out using methods of dynamic programming, optimization, recursion, and modeling. Results. We did not find similar studies in the available literature. This study was carried out using the dynamic programming method, which is designed to solve the problem of finding the target function(s) F(i) of regional projects. The authors attempted to find a prototype of an operating procedure at the level of project executors, which is indivisible and elementary for subsequent optimization of the variable (non-constant) elements of the prototype of a medical organization model from the found objective function. Finding F(i) by categories of patients (object of influence) registered at the dispensary, obtained using the callback function F(0), F(1), F(2), F(3), …F(k); F (0) ←F (1) ←F (2) ← F (3) ……F(n‑1) ← Fn (recursion) consists of decomposing the problem into smaller subproblems, finding the optimal solution to the subproblems recursively and using the resulting solution subtasks for constructing a solution to the original problem – optimizing an element of a prototype model of a medical organization, a regional project as a whole. Conclusion. The main tasks associated with project optimization are the tasks of minimizing the cost of the project for a given deadline for its implementation and minimizing (maximizing) the project completion period for a given marginal cost of its implementation. In search of a solution to optimization issues, the authors proposed finding F(i) by categories of patients (object of influence) registered as “D”, obtained using the callback function F (0) ←F (1) ←F (2) ← F (3) ……F(n‑1) ← Fn (recursion).

The explicit bonding reaction ensemble Monte Carlo method.

We present the explicit bonding Reaction ensemble Monte Carlo (eb-RxMC) method, designed to sample reversible bonding reactions in macromolecular systems in thermodynamic equilibrium. Our eb-RxMC method is based on the reaction ensemble method; however, its implementation differs from the latter by the representation of the reaction. In the eb-RxMC implementation, we are adding or deleting bonds between existing particles, instead of inserting or deleting particles with different chemical identities. This new implementation makes the eb-RxMC method suitable for simulating the formation of reversible linkages between macromolecules, which would not be feasible with the original implementation. To enable coupling of our eb-RxMC algorithm with molecular dynamics algorithm for the sampling of the configuration space, we biased the sampling of reactions only within a certain inclusion radius. We validated our algorithm using a set of ideally behaving systems undergoing dimerization and polycondensation reactions, for which analytical results are available. For dimerization reactions with various equilibrium constants and initial compositions, the degree of conversion measured in our simulations perfectly matched the reference values given by the analytical equations. We also showed that this agreement is not affected by the arbitrary choice of the inclusion radius or the stiffness of the harmonic bond potential. Next, we showed that our simulations can correctly match the analytical results for the distribution of the degree of polymerization and end-to-end distance of ideal chains in polycondensation reactions. Altogether, we demonstrated that our eb-RxMC simulations correctly sample both reaction and configuration spaces of these reference systems, opening the door to future simulations of more complex interacting macromolecular systems.

Обзор программных комплексов в области охраны труда

The article is dedicated to the issues of the application of various occupational safety software products at enterprises of different spheres of activities. The implementation of electronic document management in the sphere of occupational safety has been substantiated; the legislative basics for document management and occupational safety management by electronic tools at enterprises have been considered. References to the basic regulatory legal acts covering the use of information systems in occupational safety electronic document management have been provided. The main software products existing in the market of occupational safety information systems have been reviewed and analyzed. Comparative characteristics of functional capabilities and consumer properties of basic software products used for the arrangement of occupational safety document management have been provided. It is shown that the computerization tools of occupational safety by functionality can contain the following basic elements: automated workplaces, training and control systems, information and analytical systems, and reference systems. Potential positive and negative features of various approaches to the choice of occupational safety software products have been noted. The recommendations on the choice of occupational safety software tools in accordance with the specifics of the enterprise have been provided. In terms of functional capabilities, it is essential to select an occupational safety software considering the specifics of a company, such as its activity field, number of employees, financial capabilities, etc. Therefore, in many cases, «flexible» software products that allow a client or a supplier to adapt the software and integrate it into the already existing system of the company’s document management are chosen.

XXVII МНТК “Геофорум-2024”

Information about the next, traditional, annual International Scientific and Technical Conference “Geoforum-2024” (April 10-12, 2024, Lviv-Bryukhovychi), organized as always by the Western Geodetic Society of UTGC. The conference featured a ceremonial opening, plenary and sectional meetings, presentations, a professional exhibition of geodetic and photogrammetric equipment and modern technologies, as well as scientific and educational literature. A round table was held dedicated to the 20th anniversary of the USK 2000 DGM and the development of the national geodetic reference system. The resolution adopted by the “Geoforum-2024” ISTC is aimed at solving urgent problems in the field. Participants included specialists from various regions of Ukraine and abroad.

Revisiting the Excitation of Free Core Nutation

AbstractEarth possesses a Poincaré mode called Free Core Nutation (FCN) due to the misalignment of the rotation axes of the mantle and fluid outer core. FCN is the primary signal in the observations of Celestial Pole Offsets (CPO) and maintained by geophysical mechanisms that are yet to be understood. Earlier studies suggested an origin in Atmospheric Angular Momentum (AAM)—and to a lesser degree Oceanic Angular Momentum (OAM)—but discrepancies between these geophysical excitations and the geodetic (CPO‐based) excitation were too large to reach definite conclusions. Here we use newly calculated, 3‐hourly AAM and OAM series for the 1994–2022 period, in conjunction with the latest CPO series from the International Earth Rotation and Reference Systems Service (IERS 20 C04 series), to demonstrate a markedly lower power ratio (4.6) of geophysical over geodetic excitation at the FCN frequency compared to previous works (ratio 10). Among all excitation sources, the AAM pressure term exhibits the highest coherence (0.56) and correlation (0.48) with the geodetic excitation, whereas the coherence with OAM is smaller by a factor of 3. Similar analyses using existing angular momentum series give comparable, albeit smaller coherence and correlation results. We attribute the relevant AAM pressure term signal to Northern Hemispheric landmasses and further show consistent temporal variations in the amplitude of geophysical and geodetic excitations around the FCN band. Our results thus corroborate evidence for large‐scale atmospheric mass redistribution to be the main cause of continuous FCN excitation.