bluuebunny/crossref_metadata_2025 huggingface dataset:
In Rare Opportunity, Researchers Observe Formation of Icelandic Valleys
Authors: Stanley Sarah
Published: August 2024

During the lead-up to recent volcanic eruptions near the city of Grindav�k, scientists documented graben formation in real time.
GLocal: A global development dataset of subnational administrative areas
Authors: Morales-Arilla Jose , Gadgin Matha Shreyas
Published: August 2024

The purpose of the GLocal dataset is to enable research in international development that requires both global scope and local precision. Leveraging modern geospatial analysis tools, we process a diverse array of sources to provide researchers with a growing set of economic, demographic, ecological and socio-political variables for geographic units relevant to public policy. We provide separate data files for different levels of administrative and periodic aggregation, along with ad-hoc files with more detailed information on specific topics. In this data descriptor paper, we discuss both our data processing methodologies and validation pipelines, and provide a short case study to illustrate the research potential of the dataset. We also introduce a simple web app, glocal.streamlit.app, which offers a user-friendly interface for exploring and visualizing the dataset. Given the growing number of public and granular sources of relevance for international development research, we hope to continue adding features and expand the GLocal dataset in the future.
The effects of facial appearance on measures of generalized trust
Authors: Robbins Blaine G. , Grigoryeva Maria S.
Published: August 2024

Research suggests various associations between generalized trust and a wide range of economic, political, and social dimensions. Despite its importance, there is considerable debate about how best to measure generalized trust. One recent solution operationalizes generalized trust as the average of trust ratings across a small set of trust domains and human faces. Here, we investigate whether heterogeneity in facial appearance affects the psychometric properties of these new instruments. In a survey experiment conducted with a sample of U.S. adults (n = 5001), we randomly assigned respondents to one of five conditions that varied the features of human and AI-synthesized faces. Irrespective of the condition, respondents rated each face along four trust domains. We find that facial heterogeneity has negligible effects on the measurement validity and measurement equivalence of these new instruments. Small differences are observed on a subset of faces for some psychometric tests. These findings contribute to a growing body of work using faces to measure generalized trust, and demonstrate the utility of using AI-synthesized faces in social science research more broadly.
Sustainable practices in manufacturing: harnessing deep learning techniques
Authors: Chacko Mathew
Published: August 2024

The manufacturing industry stands at a crossroads, facing the dual challenge of meeting growing global demand while addressing environmental concerns. Sustainable practices have emerged as a paramount focus, and the integration of deep learning techniques offers a promising avenue for achieving sustainability goals during the manufacturing of parts A deep learning approach for online fault recognition via automatic image processing is developed to identify defects and thereby prevent non-conformities in the Computer Numerically Controlled (CNC) manufacturing process. Analytical research was conducted wherein in-process images of tool wear acquired during the CNC manufacturing process are analyzed via a bi-stream Deep Convolutional Neural Network-based model. Experimental evaluations confirmed the effectiveness of the deep learning methods for the detection and ResNet was identified as the best Deep Learning (DL) algorithm to predict the quality of the part produced with a batch size of 8 epoch 50 learning rate .0001 together with RMS prop optimizer, to hyper-tune the model. This deep learning framework, together with machine learning models like X.G.Boost incorporating real-time data acquisition of input parameters, was able to predict the final quality of the parts manufactured with an accuracy of 96.58% fostering sustainable practices within the manufacturing environment directly impacting 14 KPI’s and indirectly 7KPI’s of the sustainability index.
Research Trends in Machine Learning Applications for Predicting Ecosystem Responses to Environmental Changes
Authors: Maulana Fairuz Iqbal , Adi Puput Dani Prasetyo , Puspitasari Chasandra , Purnomo Agung
Published: August 2024

This research discusses the trends in machine learning (ML) applications for predicting ecosystem responses to environmental changes. A keyword search was conducted in the WoS database using Boolean operators to identify relevant peer-reviewed articles. The search focused on English-language documents published between 2014 and 2023, while excluding non-original articles. Bibliometric data, includingpublication trends, citation counts, author collaboration patterns, and keyword analysis, were extracted from 554 retrieved articles. The data was then analyzed and visualized using R and VOSViewer. The study highlights the significant growth in annual scientific production, reflecting a growing interest in thisinterdisciplinary field. Core concepts such as “climate change,” “biodiversity,” and “ecological responses” continue to receive significant attention, while contemporary themes like “variability,” “time-seriesanalysis,” and “organic matter” are emerging. Co-authorship networks demonstrate extensive collaborationsacross countries, with the United States and China playing prominent roles. The research topics have evolvedfrom “ecological responses” and “community” to a focus on “model,” “optimization,” and “performance,” with an emphasis on fine-tuning models to incorporate climate variability.
Identification of pathogenic gene variants in carpal tunnel syndrome using bioinformatics approaches
Authors: Humolungo Dwi Tiva Widyanti S. , Anjani Ratna , Irham Lalu Muhammad , Sulistyani Nanik , Ma’ruf Muhammad , Amukti Danang Prasetyaning , Adikusuma Wirawan , Sarasmita Made Ary , Khairi Sabiah , Purwanto Barkah Djaka , Suyatmi Suyatmi , Siswanto Lalu Muhammad Harmain , Satria Rahmat Dani , Pranata Satriya , Chong Rockie
Published: August 2024

Carpal Tunnel Syndrome (CTS) is one of the disorders that occur in the upper extremities caused by a narrowing in the carpal tunnel so that there is pressure on the median nerve located in the wrist. In this study, pathogenic variants associated with Carpal Tunnel Syndrome (CTS) were prioritized using bioinformatics and genetic data in populations. The study used GWAS data to identify single nucleotide polymorphisms to look for genomic variants associated with CTS. The data obtained is then continued using HaploReg and GTEx portal for analysis with ensembles. Furthermore, the results of the GTEx portal identified genetic variants with gene expression throughout human tissue. The results obtained obtained two gene variants, namely rs61749613 encoded by VCAN and rs62621197 encoded by ADAMTS10. Of the two variants, the gene as a whole can be expressed in the aortic tissue. The allele frequency distribution of the two gene variants obtained different results from each continent.
Design and analysis of a high-efficiency Tri-Band MIMO antenna for advanced communication systems
Authors: Chbeine Moussab , Azmani Monir , Astito Abdelali , Dkiouak Aziz , Bayjja Mohamed
Published: August 2024

In this article, we introduce a novel design of a tri-band two-element MIMO antenna, powered by a microstrip line. This precisely designed antenna incorporates radiators symmetrically arranged on the Rogers RT5880 substrate, displaying optimized dimensions of 31×11×0.8 mm3. Our approach is characterized by the addition of a comb-shaped etched motif on each rectangular patch element. This feature has demonstrated its effectiveness to operate at frequencies of 24 GHz, 31 GHz, and 36 GHz. In detail, the 24 GHz band is particularly suited for high-quality satellite communications, the 31 GHz frequency is suitable for high-resolution radar applications, and the 36 GHz band is optimized for high-velocity point-topoint communication links. On the other hand, the prototype of the proposed MIMO antenna is simulated, and the mutual coupling between the ports is less than 21 dB. Consequently, the antenna performance metrics, such as the Envelope Correlation Coefficient (ECC) is less than 0.01 with a maximum Diversity Gain (DG) of about 9.95 dB, and the antenna maintains high efficiency of up to 94% across the entire operational band. Additionally, the MIMO antenna exhibits a gain of 7.26 dBi, 6.82 dBi, 7.26 dBi respectively, affirming this MIMO antenna as an excellent candidate for multi-band applications within the realm of fifth-generation wireless communications.
Improving data security with the utilization of matrix columnar transposition techniques
Authors: Tulus  , Sy Syafrizal , Sugeng Kiki A. , Simanjuntak Rinovia , Marpaung J.L.
Published: August 2024

The Graph Neural Network (GNN) is an advanced use of graph theory that is used to address complex network problems. The application of Graph Neural Networks allows the development of a network by the modification of weights associated with the vertices or edges of a graph G (V, E). Data encryption is a technique used to improve data security by encoding plain text into complex numerical configurations, hence minimizing the probability of data leaking. This study seeks to explain the potential of improving data security through the application of graph neural networks and transposition techniques for information manipulation. This study involves an algorithm and simulation that discusses the use of the transposition approach in manipulating information. This is accomplished by the implementation of a graph neural network, which develops the interaction between vertices and edges. The main result of this research shows empirical evidence supporting the notion that the length of the secret key and the number of characters utilized in data encryption have a direct impact on the complexity of the encryption process, hence influencing the overall security of the created data.
An integrated structural model of the DNA damage-responsive H3K4me3 binding WDR76:SPIN1 complex with the nucleosome
Authors: Liu Xingyu , Zhang Ying , Wen Zhihui , Hao Yan , Banks Charles A.S. , Cesare Joseph , Bhattacharya Saikat , Arvindekar Shreyas , Lange Jeffrey J. , Xie Yixuan , Garcia Benjamin A. , Slaughter Brian D. , Unruh Jay R. , Viswanath Shruthi , Florens Laurence , Workman Jerry L. , Washburn Michael P.
Published: August 2024

Serial capture affinity purification (SCAP) is a powerful method to isolate a specific protein complex. When combined with cross-linking mass spectrometry and computational approaches, one can build an integrated structural model of the isolated complex. Here, we applied SCAP to dissect a subpopulation of WDR76 in complex with SPIN1, a histone reader that recognizes trimethylated histone H3 lysine4 (H3K4me3). In contrast to a previous SCAP analysis of the SPIN1:SPINDOC complex, histones and the H3K4me3 mark were enriched with the WDR76:SPIN1 complex. Next, interaction network analysis of copurifying proteins and microscopy analysis revealed a potential role of the WDR76:SPIN1 complex in the DNA damage response. Since we detected 149 pairs of cross-links between WDR76, SPIN1, and histones, we then built an integrated structural model of the complex where SPIN1 recognized the H3K4me3 epigenetic mark while interacting with WDR76. Finally, we used the powerful Bayesian Integrative Modeling approach as implemented in the Integrative Modeling Platform to build a model of WDR76 and SPIN1 bound to the nucleosome.
Correlating local structure and migration dynamics in Na/Li dual ion conductor Na
5
YSi
4
O
12
Authors: Lou Chenjie , Liu Jie , Sun Xuan , Zhang Wenda , Xu Ligang , Luo Huajie , Chen Yongjin , Gao Xiang , Kuang Xiaojun , Fu Jipeng , Xu Jun , Su Lei , Ma Jiwei , Tang Mingxue
Published: August 2024

Na
5
YSi
4
O
12
(NYSO) is demonstrated as a promising electrolyte with high ionic conductivity and low activation energy for practical use in solid Na-ion batteries. Solid-state NMR was employed to identify the six types of coordination of Na
+
ions and migration pathway, which is vital to master working mechanism and enhance performance. The assignment of each sodium site is clearly determined from high-quality
23
Na NMR spectra by the aid of Density Functional Theory calculation. Well-resolved
23
Na exchangespectroscopy and electrochemical tracer exchange spectra provide the first experimental evidence to show the existence of ionic exchange between sodium at Na5 and Na6 sites, revealing that Na transport route is possibly along three-dimensional chain of open channel−Na4−open channel. Variable-temperature NMR relaxometry is developed to evaluate Na jump rates and self-diffusion coefficient to probe the sodium-ion dynamics in NYSO. Furthermore, NYSO works well as a dual ion conductor in Na and Li metal batteries with Na
3
V
2
(PO
4
)
3
and LiFePO
4
as cathodes, respectively.
The yielding of granular matter is marginally stable and critical
Authors: Shang Jin , Wang Yinqiao , Pan Deng , Jin Yuliang , Zhang Jie
Published: August 2024

Amorphous materials undergo a transition from liquid-like to solid-like states through processes like rapid quenching or densification. Under external loads, they exhibit yielding, with minimal structural changes compared to crystals. However, these universal characteristics are rarely explored comprehensively in a single granular experiment due to the added complexity of inherent friction. The discernible differences between static configurations before and after yielding are largely unaddressed, and a comprehensive examination from both statistical physics and mechanical perspectives is lacking. To address these gaps, we conducted experiments using photoelastic disks, simultaneously tracking particles and measuring forces. Our findings reveal that the yielding transition demonstrates critical behavior from a statistical physics standpoint and marginal stability from a mechanical perspective, akin to the isotropic jamming transition. This criticality differs significantly from spinodal criticality in frictionless amorphous solids, highlighting unique characteristics of granular yielding. Furthermore, our analysis confirms the marginal stability of granular yielding by assessing the contact number and evaluating the balance between weak forces and small gaps. These factors serve as structural indicators for configurations before and after yielding. Our results not only contribute to advancing our understanding of the fundamental physics of granular materials but also bear significant implications for practical applications in various fields.
Structure of biofilm-forming functional amyloid PSMα1 from
Staphylococcus aureus
Authors: Hansen Kasper Holst , Byeon Chang Hyeock , Liu Qian , Drace Taner , Boesen Thomas , Conway James F. , Andreasen Maria , Akbey Ümit
Published: August 2024

Biofilm-protected pathogenic
Staphylococcus aureus
causes chronic infections that are difficult to treat. An essential building block of these biofilms are functional amyloid fibrils that assemble from phenol-soluble modulins (PSMs). PSMα1 cross-seeds other PSMs into cross-β amyloid folds and is therefore a key element in initiating biofilm formation. However, the paucity of high-resolution structures hinders efforts to prevent amyloid assembly and biofilm formation. Here, we present a 3.5 Å resolution density map of the major PSMα1 fibril form revealing a left-handed cross-β fibril composed of two C
2
-symmetric U-shaped protofilaments whose subunits are unusually tilted out-of-plane. Monomeric α-helical PSMα1 is extremely cytotoxic to cells, despite the moderate toxicity of the cross-β fibril. We suggest mechanistic insights into the PSM functional amyloid formation and conformation transformation on the path from monomer-to-fibril formation. Details of PSMα1 assembly and fibril polymorphism suggest how
S. aureus
utilizes functional amyloids to form biofilms and establish a framework for developing therapeutics against infection and antimicrobial resistance.
A DNA condensation code for linker histones
Authors: Watson Matthew , Sabirova Dilyara , Hardy Megan C. , Pan Yuming , Carpentier David C. J. , Yates Henry , Wright Charlotte J. , Chan W. H. , Destan Ebru , Stott Katherine
Published: August 2024

Linker histones play an essential role in chromatin packaging by facilitating compaction of the 11-nm fiber of nucleosomal “beads on a string.” The result is a heterogeneous condensed state with local properties that range from dynamic, irregular, and liquid-like to stable and regular structures (the 30-nm fiber), which in turn impact chromatin-dependent activities at a fundamental level. The properties of the condensed state depend on the type of linker histone, particularly on the highly disordered C-terminal tail, which is the most variable region of the protein, both between species, and within the various subtypes and cell-type specific variants of a given organism. We have developed an in vitro model system comprising linker histone tail and linker DNA, which although very minimal, displays surprisingly complex behavior, and is sufficient to model the known states of linker histone-condensed chromatin: disordered “fuzzy” complexes (“open” chromatin), dense liquid-like assemblies (dynamic condensates), and higher-order structures (organized 30-nm fibers). A crucial advantage of such a simple model is that it allows the study of the various condensed states by NMR, circular dichroism, and scattering methods. Moreover, it allows capture of the thermodynamics underpinning the transitions between states through calorimetry. We have leveraged this to rationalize the distinct condensing properties of linker histone subtypes and variants across species that are encoded by the amino acid content of their C-terminal tails. Three properties emerge as key to defining the condensed state: charge density, lysine/arginine ratio, and proline-free regions, and we evaluate each separately using a strategic mutagenesis approach.
Fundamental frequency as an acoustic mirror of interpreters’ cognitive states
Authors: Shao Zhangminzi , Defrancq Bart
Published: August 2024

The present study proposes the acoustic parameter of fundamental frequency (F0) as an alternative method for gauging interpreters’ cognitive load and fatigue during simultaneous interpreting (SI). The data collected from an English-Chinese SI experiment reported in Shao and Chai (2021) were re-analysed for the purposes of this study. Cognitive load was measured as the number of undelivered information chunks within the ear-voice span (EVS), whereas fatigue was assumed to increase with time. F0 variables were correlated with cognitive load within the EVS of selected sentences and with fatigue in one-minute segments distributed over the entire interpreting performance. The results show that cognitive constructs are associated in various ways with F0-related variables. Higher F0 peaks and a wider F0 range appear to be associated with higher cognitive load in a majority of interpreters. A higher mean F0 and, to a lesser extent, higher F0 peaks are associated with fatigue. The findings suggest that F0 could be used as a promising indicator of cognitive load and fatigue in SI.
AFRIMETS supplementary comparison on calibration of setting rods
Authors: ElMelegy Ahmed , Obayi Bede , Bore Calvin , James Joseph , Charles Angela , Mutale Daniel , Gandah Burnhard , Kame Modiriemang , Ntima Pamidzani , Pryam Tomeswar , Pallut Ramasawmy
Published: August 2024

Main text

National Metrology Institutes from 8 African countries, namely Egypt, Nigeria, Kenya, Tanzania, Zambia, Zimbabwe, Botswana, and Mauritius have participated in an international supplementary comparison on the calibration of setting rods.

This comparison was a part of larger supplementary comparison between 13 African countries for the calibration of hand measuring instruments. This larger comparison which was carried out during the period between December 2019 - December 2022 has been piloted by NIS, Egypt and has been registered in BIPM-KCDB database on December 2019. The artifacts have been prepared by NIS, Egypt and measured before sent to circulate between all participant countries in round-robin scheme and returned back again for NIS, Egypt where a final measurement was made for stability check.

The main purpose of these comparisons is to support submission of CMCs for calibration of hand length measuring instruments in BIPM-KCDB.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
AFRIMETS supplementary comparison on pin gauges
Authors: ElMelegy Ahmed , Obayi Bede , Mutale Daniel , Gandah Burnhard , Kame Modiriemang , Ntima Pamidzani , Pryam Tomeswar , Pallut Ramasawmy
Published: August 2024

Main text

National Metrology Institutes from 6 African countries, namely Egypt, Nigeria, Zambia, Zimbabwe, Botswana, and Mauritius have participated in an international supplementary comparison on the calibration of pin gauges.

This comparison was a part of larger supplementary comparison between 13 African countries for the calibration of hand measuring instruments. This larger comparison which was carried out during the period between December 2019 - December 2022 has been piloted by NIS, Egypt and has been registered in BIPM-KCDB database on December 2019. The artifacts have been prepared by NIS, Egypt and measured before sent to circulate between all participant countries in round-robin scheme and returned back again for NIS, Egypt where a final measurement is made for stability check.

The main purpose of these comparisons is to support submission of CMCs for calibration of hand length measuring instruments in BIPM-KCDB.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCL, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Fluctuation-induced first order transition to collective motion
Authors: Martin David , Spera Gianmarco , Chaté Hugues , Duclut Charlie , Nardini Cesare , Tailleur Julien , van Wijland Frédéric
Published: August 2024

The nature of the transition to collective motion in assemblies of aligning self-propelled particles remains a long-standing matter of debate. In this article, we focus on dry active matter and show that weak fluctuations suffice to generically turn second-order mean-field transitions into a ‘discontinuous’ coexistence scenario. Our theory shows how fluctuations induce a density-dependence of the polar-field mass, even when this effect is absent at mean-field level. In turn, this dependency on density triggers a feedback loop between ordering and advection that ultimately leads to an inhomogeneous transition to collective motion and the emergence of inhomogeneous travelling bands. Importantly, we show that such a fluctuation-induced first order transition is present in both metric models, in which particles align with neighbors within a finite distance, and in ‘topological’ ones, in which alignment is based on more complex constructions of neighbor sets. We compute analytically the noise-induced renormalization of the polar-field mass using stochastic calculus, which we further back up by a one-loop field-theoretical analysis. Finally, we confirm our analytical predictions by numerical simulations of fluctuating hydrodynamics as well as of topological particle models with either k-nearest neighbors or Voronoi alignment.
Logical Mapping-based hierarchical safe reinforcement learning for autonomous driving
Authors: Nie Jihui , Li Yingda
Published: August 2024

Making decisions in complex and multiple scenarios presents great challenges for autonomous driving systems (ADS). In recent years, deep reinforcement learning algorithms (DRL) have made remarkable breakthroughs in decision-making. However, there remain many problems, such as sparse reward and slow convergence in traditional DRL when facing multiple sub-goals. In this paper, we propose a hierarchical deep deterministic policy gradient (DDPG) based on the BDIK model for autonomous driving, which enables ADS to have the ability to make decisions in human-like deliberation ways as well as deal with uncertainties in the environment. First, we propose the BDIK model based on the Beliefs-Desires-Intentions (BDI) model so that the agents are guided by domain knowledge when generating their sub-goals. Furthermore, in contrast to traditional BDI systems making plans by hand, a BDIK hierarchical DDPG (BDIK HDDPG) algorithm is employed to deduce the optimal actions automatically in an uncertain environment. The results show that our method outperforms the standard DDPG for both processing speed and effectiveness in multiple and complex scenarios.
Fractional order Lipschitz recurrent neural network with attention for long time series prediction
Authors: Zhu Zelong , Zhao Chunna , Huang Yaqun
Published: August 2024

Time series data prediction holds a significant importance in various applications. In this study, we specifically concentrate on long-time series data prediction. Recurrent Neural Networks are widely recognized as a fundamental neural network architecture for processing effectively time-series data. Recurrent Neural Network models encounter the gradient disappearance or gradient explosion challenge in long series data. To resolve the gradient problem and improve accuracy, the Fractional Order Lipschitz Recurrent Neural Network (FOLRNN) model is proposed to predict long time series in this paper. The proposed method uses the Lipschitz continuity to alleviate the gradient problem. The fractional order integration is applied to compute the hidden states of the Recurrent Neural Network in the proposed method. The intricate dynamics of long-time series data can be captured by fractional order calculus. It has more accurate predictions compared with Lipschitz Recurrent Neural Networks models. Then self-attention is used to improve feature representation. It can describe the correlation of features and improve predict performance. Some experiments show that the FOLRNN model achieves better results than other methods.
Research on regional difference mechanism of circulation innovation based on panel regression model
Authors: Li Chongyan , Li Xianke
Published: August 2024

The panel regression model is remarkably persuasive in exploring the causal relationship. Therefore, combined with China’s macroeconomic data from 2004 to 2021, this paper uses a panel regression model to reveal the influence mechanism of regional differences affecting innovation flow. Using the improved Theil index to construct panel data of regional differences, this paper explores the reasons for the unbalanced development of technological innovation circulation in China. The empirical results of the fixed effects model show that after controlling for the differences in economic opening environment and firm profit space, the differences in government support and circulation environment significantly affect the regional differences in technological innovation circulation level. This result helps to verify the existence of a “double wheel drive” mechanism in the construction of China’s circulation innovation system, that is, the dual leading role of “effective government” and “efficient market” with Chinese characteristics.
Harnessing RES Potential in Balkan Peninsula
Authors: Vokshi Adi , Zgureva-Filipova Denitza , Markov Detelin
Published: August 2024

The Balkan Peninsula presents a unique and compelling case study for the harnessing of renewable energy sources (RES) to meet growing energy demands sustainably. This paper investigates the current status and future potential of RES deployment across eleven countries in the region: Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Greece, Kosovo, Montenegro, North Macedonia, Romania, Serbia, and Slovenia. In this comprehensive analysis, we begin by providing an overview of the installed capacity of RES in these countries for the year 2021, drawing upon data from reputable sources such as the International Renewable Energy Agency (IRENA) and national energy agencies. Building upon this foundation, we delve into an in-depth examination of the wind and solar energy potential in the region, utilizing geographic information system (GIS) data and modelling techniques to assess resource availability and feasibility. Furthermore, we explore two distinct scenarios for maximizing solar energy deployment in the Balkans. Firstly, we analyse the implications of covering the entire territory of each country with solar panels, estimating the potential electricity production and its relation to current consumption levels. Secondly, we use a more pragmatic approach, focusing on the strategic deployment of solar panels in areas with the highest energy generation potential, while considering land use constraints and environmental considerations. In addition to evaluating the technical and economic aspects of RES deployment, we also quantify the environmental benefits in terms of carbon emissions reduction. By comparing emissions from renewable sources with those from conventional fossil fuel-based electricity generation, we highlight the significant contribution of RES to mitigating climate change and achieving sustainability goals. In conclusion, this paper underscores the immense potential of renewable energy in the Balkans and emphasizes the importance of strategic planning and policy interventions to unlock this potential. By leveraging the region’s abundant natural resources and embracing innovative technologies, the Balkan countries can chart a course towards a more resilient, equitable, and sustainable energy future.
An initial evaluation of humidified discharge cycle for liquid air energy storage
Authors: Borissova Ana , Hristov Kaloyan , Popov Dimityr
Published: August 2024

The research community is becoming more interested in liquid air energy storage among the leading innovative technologies for long duration and grid-scale energy storage. Practical Uses of liquid air energy storage are currently somewhat limited, though, mostly due to the intricate design of LAES plants and the poor “roundtrip efficiency” that is the ratio of the energy recovered from the LAES system during the discharge cycle to the total energy input. With so many components already present in the LAES plant, nearly every research project underway adds even more complexity to the mix. The objective of the work that is being presented aims to increase the use of the heat of compression that has been stored during the charging without adding additional complexity. A mixture of water vapour and air, or humidified air, serves as the working fluid in the presented concept. Thermodynamic performance of the proposed discharge configuration is evaluated and compared on a consistent basis with the stand alone LAES system. The results demonstrate significant increase in the roundtrip efficiency.
Investigation and Mathematical Modelling of Anaerobic Biofermentation of Dairy Cattle Manure: Influence of Addition of Citrus Peel Waste and Lycoperdon Perlatum Spores
Authors: Tzanova Anelia I. , Koparanov Kiril A. , Antonova Elena V. , Minkovska Daniela V. , Antonov Svetlin , Stefanov Bozhidar I.
Published: August 2024

The production of biogas from organic and carbon-neutral sources through biomethanization is essential for achieving the goals of the circular economy and reducing carbon emissions. Crucial for the optimal efficiency of anaerobic biofermentation processes is the influence of organic substrate and the application of methanogenesis enhancement additives. This study explores the possibilities of using a substrate of citrus biomass (waste peelings) for methane production from dairy cattle manure, as well as the influence of an addition of puffball mushroom (Lycoperdon perlatum) spores on the process. Experimental data obtained over a period of 31 days were mathematically modelled using a Verhulst logistic growth model to forecast their future development. The results indicate an inhibitory effect of citrus biomass on methanogenesis processes with a 20% lower yield, but a positive effect of Lycoperdon perlatum spores with nearly double the amount of biogas produced and higher methane content.
Study of the thermal behavior of pellets made from different waste materials
Authors: Mileva N , Radenkov V , Zlateva P
Published: August 2024

The study of waste materials pellets by some thermal analysis methods represents an important area of research and industrial practice. Thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTG) were used for this study. Five different types of pellets were analyzed at heating rates of 5°C/min and 10°C/min up to a temperature of 750°C. The results of this study contribute to a better understanding of the thermal properties of pellets and their behavior under different temperature conditions. This analytical approach not only provides important information for improving the quality and efficiency of pellets but also can be beneficial for optimizing their production processes. The results obtained are expected to be relevant for the development of innovative solutions in areas such as the energy sector, manufacturing, and biomass industries while helping to achieve sustainable resource use and waste reduction.
Simulation of winter heat fluxes through a clay wall with added wheat straw using the finite element method
Authors: Tashkov L , Zlateva P
Published: August 2024

This study focuses on the simulation of heat transfer through a brick wall using an experimental model of unfired ceramic bricks with different additions of wheat straw. A digital model of the wall was created using computer software. Using the finite element method, the behavior of the external brick wall of a residential building is analyzed under changing external temperatures and constant internal temperature. The analysis process is divided into two main parts. The first part covers the stationary problem, which determines the temperature distribution in the wall. In the second part, this solution serves as an initial condition for dynamic analysis. This approach allows investigating how the wall responds to heat by analyzing the dynamic temperature distribution, heat flow and stored energy in the wall. The analyzes will serve to improve the energy efficiency and comfort of residential buildings.
Modelling of hydrocarbon synthesis process using barrier discharge
Authors: Iliev I.K. , Gizzatullin A. R. , Filimonova A. A. , Chichirova N. D. , Malanichev V.E. , Kangalov Plamen G.
Published: August 2024

A computational model for hydrocarbon synthesis by natural gas decomposition using barrier discharge is presented. The model describes the kinetics of the main reactions occurring in the plasma and accounts for the following processes: excitation/relaxation by direct electron impact, decomposition and ionization by electron impact, charge loss due to diffusion to the walls, and 92 chemical reactions. The rates of hydrocarbon production under various discharge parameters and changes in the composition of the starting gas have been calculated. The calculated rates of hydrocarbon production and discharge parameters were correlated with experimental data. The deviation of the calculated electrical parameters from the experiment does not exceed 7%. The model also demonstrated high accuracy in terms of product selectivity and their production rates. The calculations showed a promising result that the synthesis process efficiency depends on the signal shape while maintaining constant power input into the discharge.
A direct coupled photovoltaic - electrolyser system for producing green hydrogen
Authors: Gavrailov D Y , Boycheva S V , Gao Xin
Published: August 2024

This study focuses on the direct coupling between photovoltaic modules (PV) and Proton Exchange Membrane Electrolysers (PEMEC) through data collection to ascertain an optimal and highly efficient operational configuration. The objective is to align the maximum power point line (MPPL) of PV panels with the current-voltage (I-V) characteristic curve of the electrolyser, thereby obviating the need for a DC to DC converter and simplifying the connection while reducing costs and losses. We utilized a polarization curve of Proton Exchange Membrane Electrolyser modelled in COMSOL Multiphysics software and a single PV module with a peak power of 220W. This arrangement necessitates thorough sizing and investigation to achieve maximum system efficiency and green hydrogen production.
Audit of opportunities for improving the energy performance of office buildings by renewable sources
Authors: Penev A D , Rusev S B
Published: August 2024

This paper represents a simple approach to an energy audit for using different types of renewable sources integrated into office buildings. Regression analysis of the results of the simulations with the baseline of the building’s energy consumption and identifying the significant energy use of the buildings were done. It studied various options for building facilities for producing energy from renewable sources on the roof structures and options for a covered parking lot with photovoltaic (PV) panels around the buildings. The technical-economic analysis of the financial indicators of the different types of renewable sources was made and in conclusion were calculated the best payback period (PB), internal rate of return (IRR), net present value (NPV), net present value coefficient (NPVQ), etc.
Model predictive control design for axial-piston pump
Authors: Mitov A , Kralev J , Slavov Ts
Published: August 2024

The article presents model predictive control (MPC) design of the displacement volume control of a variable displacement axial-piston pump. The pump is intended for application in open loop circuit hydraulic drive system. The authors are developed a real-time control system contains two basic components: an electro-hydraulic proportional valve and an industrial controller. The proportional valve replaced the conventional hydro-mechanical controller that changes the swash plate swivel angle, and hence the displacement volume, respectively the flow rate of the pump. The system was developed as a laboratory test bench enabling experimental investigation. The authors are performed system identification based on experimental data and obtained a state space mathematical model of the system. This model was used to synthesize the MPC controller. The behaviour of the controller has been studied both in simulation and in experimental conditions. The analysis of the control performance is carried out comparing transients’ response at different flow rates reference and pump load modes.
Toward detailed modeling of tires with linear elastic rubber compounds using finite element method
Authors: Tchuigwa Baurice Sylvain Sadjiep , Krmela Jan , Pokorny Jan
Published: August 2024

Against a backdrop of increasing depletion of natural and energy resources and worsening global warming, the tire industry, like many other industries, is currently confronted with the pressing need to enhance not only its resilience but also the sustainability and cost-effectiveness of its products through advanced numerical simulations. Numerical simulation is a valuable tool in the tire development process that provides manufacturers with in-depth insights into their products from design to mass production. This paper aims to introduce a detailed finite element-based modeling process for tires that can be used for a wide range of simulations, including steady state, transient rolling, and failure scenarios such as layer delamination, blowout, and part breakage. The selected tire for the implementation in this study is designated 175/75R14 and was modeled in a static loading setup in ABAQUS standard with an implicit scheme considering linear elastic rubber compounds and other assumptions. Unlike the commonly used homogenized approach for reinforced layers, the proposed method takes into account the real physical and mechanical properties of the tire structure. In addition, important information pertaining to the creation of mesh and the interactions between elements is provided. The obtained results align with the assumptions and can serve as a proof of concept for more detailed and advanced tire modeling and enhancement in the future.
A numerical study of the influence of the choice of rubber material behavior on the static response of tires
Authors: Tchuigwa Baurice Sylvain Sadjiep , Krmela Jan , Pokorný Jan
Published: August 2024

Considering the present-day environmental and energy objectives set forth by governments and aiming at minimizing carbon footprints and fuel consumption in the transportation sector, it is of utmost importance for manufacturers to enhance tire design. This is because doing so has the potential to revolutionize the automotive industry by promoting advancements in structural performance and fuel efficiency while reducing environmental impact and ensuring safer, more dependable vehicle structural performance. Moreover, such an approach has the advantage that the choice of model’s features such as the geometry and material mechanical properties, is done in a more detailed manner. The mechanical behavior of rubber compounds used in tire manufacturing has a direct impact on the static as well as the dynamic response of tires in various operating scenarios, such as steady state and transient dynamic. However, in the literature, there is a plethora of works that often consider basic rubber constitutive laws without a consistent study of the impact on the model results. Therefore, this paper proposes a comparative study of the static response of a radial tire using finite element method for different choices of incompressible rubber material behavior ranging from elastic(EL), hyperelastic(HE), visco-hyperelastic(VH) to hyper-pseudoelastic(HM). Simulations of an inflated tire and vertically loaded were conducted in ABAQUS Explicit, and the resulting radial deformation, maximum Von Mixes stress, CPU time, contact patch, and contact pressure were selected as four consistent comparisons. The results show that among the four material cases, the VH and HM material models lead to the most accurate result with a shorter CPU time with the latter. Also, their contact pressure and body stress are higher than those of the elastic and hyperelastic models, and this brings an important solution to the disparity between the calculated and experimentally measured contact pressure in previous works.
Comparison of VVER1000 plant respond during MSLB scenario using TRACE and RELAP computer codes
Authors: Stefanova Antoaneta , Groudev Pavlin
Published: August 2024

This paper presents a comparison of the results from simulation of „Main steam line break (MSLB) “accident using RELAP5/mod3.3 and TRACE50p5 computer codes. The work is based on the VVER-1000 MSLB OECD benchmark. The main purpose of this work was to demonstrate the capability of the TRACE computer code for modelling of 3D thermal hydraulic reactor vessel at the integral VVER 1000 model and to predict correctly the plant respond and spatial disturbance in the reactor vessel. In addition, this investigation was focused on validation of the correct predictability of the important integral parameters in VVER1000 TRACE 50p5 models. The other objectives were to provide the elements for the safety, to validate the safety analysis tools and to improve codes and methods for VVER comprehensive safety assessment. The investigated scenario is a “Main steam line break (MSLB) with inside diameter (ID) 580 mm” in a VVER1000 between the steam generator (SG) and the steam isolation valve (SIV), outside of the containment. This event is characterized with significant spatial effects in the core caused by asymmetric cooling and assumed stuck-out of control rods after SCRAM. One of the major concerns for this case is the possible return of power and criticality after SCRAM, as a result of the reactor core overcooling. The reactor state is at the beginning of 1st fuel campaign. For the purpose of the investigation, the simulation of MSLB accident with RELAP5/MOD3.3 and TRACE50p5 computer codes with modelling of reactor physics using point kinetics has been performed initially. Additionally, the 3D thermal hydraulic reactor vessel model with a point kinetic physics has been developed at the integral VVER1000 TRACE 50p5 model. The newly developed integral model of VVER1000 with 3D reactor vessel of TRACE50p5 has been validated with simulation of MSLB accident by code to code comparison with already validated VVER1000 models of RELAP5/MOD3.3 and 1D TRACE50p5 codes. The comparison between the results predicted by the codes demonstrates good agreement, except some of the parameters. The newly developed integral VVER1000 with 3D vessel model of TRACE50p5 predicts reasonable results. The predicted results by used computer codes demonstrate the stability of the reactor system during the accident progression of “Main steam line break”.
Evaluation of Minor Actinides Build-up in VVER Power Reactors’ Fuel Assemblies
Authors: Mitev M , Filipov K , Nedelchev L
Published: August 2024

The recent developments in the electricity production policies suggest major increase in the share of the nuclear power in the following decades. This trend will pull the nuclear spent fuel storage and handling from the current populist rhetoric to a real political and engineering task to be solved. One of the main challenges is the minor actinides build-up in the fuel during its use in the reactor core. These, together with the plutonium build-up are the main sources of residual heating and radiotoxicity of the spent nuclear fuel. Therefore a long-term solution for their further utilization should be found. The good knowledge of the isotopes content in the spent fuel is vital for investigation of the further handling possibilities. Three fuel assemblies for reactors of VVER type are studied in this paper by means of theoretical modelling. Modern codes and contemporary crossections are used for the calculations. Results for regular and extended fuel cycles are obtained for the minor actinides build-up during their operation. The obtained results provide sound basis for discussion on the further approaches for spent fuel utilization.
Regarding extension of the lifetime of lined clothing
Authors: Atanasova Radka , Pavlova Magdalena
Published: August 2024

This study focuses on sustainable fashion and a method for extending the life of lined garments. Three models of women’s jackets with a classic design, made from high-quality fabric, were selected for the study. The jackets had reached the end of their useful life due to worn lining. In the context of sustainable fashion, a sequence of actions for replacing the lining is proposed. The lining details are unstitched and digitized using a digitizer. This way they are entered into a specialized CAD system for clothing to be used as production patterns for cutting out a new lining. Fabrics with interesting patterns are chosen for the new lining. The resulting garments have a renewed design and are attractive to wear again. A survey confirms that consumers are motivated to wear the repaired garments again instead of throwing them away. This approach slows down the “fast fashion” process and reduces the environmental impact of the clothing industry.