1. Electrochemical determination of ammonia at low concentrations : detection of N[sub]2-electroreduction product in alkaline mediumBeata Rytelewska, Anna Chmielnicka, Takwa Chouki, Saim Emin, Iwona A. Rutkowska, Pawel Jozef Kulesza, 2025, izvirni znanstveni članek Opis: A Pt nanoparticle catalyst supported on partially-defective CeO₂ was developed for sensitive voltammetric detection of ammonia (NH₃) in alkaline media (0.5 mol dm⁻³ NaOH), achieving a detection limit of 2–3 μmol dm⁻³. This system enables in situ NH₃ monitoring during nitrogen electroreduction at an Fe₃P catalyst, without medium transfer, minimizing contamination. The Pt-based electrode also serves as a diagnostic tool to confirm electrolyte and gas purity. Selective NH₃ formation with negligible hydrazine or hydroxylamine by-products was confirmed via voltammetry and spectrophotometry.
Ključne besede: electrochemical analysis, ammonia determination, alkaline medium, nitrogen electroreduction, iron phosphide, electroanalytical control experiments, ceria, platinum nanoparticles, rhodium nanoparticles
Objavljeno v RUNG: 21.05.2025; Ogledov: 4; Prenosov: 0
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2. Accounting and reporting in supporting the transition to a circular economy : a bibliometric analysisYuliia Maksymiv, Nadiia Skromyda, Jurij Urbančič, 2024, izvirni znanstveni članek Opis: The development of a circular economy is an important task for socially responsible politicians, scientists and businesses. Despite growing interest in this concept over the past decade, the implementation of circular business models remains limited. One of the key barriers is the insufficient utilization of accounting and reporting capabilities, which are practical tools for transitioning to a circular economy. These tools support informed managerial decision-making in building and maintaining circular business models and processes. To explore the scientific interest in accounting and reporting as a means of supporting the transition to and development of a circular economy, a bibliometric analysis was conducted. This analysis utilized data from the Scopus database (845 documents from 2004 to 2024) and was further processed using VOSviewer to construct maps based on bibliographic data. The data allowed for the identification of authors and their collaboration clusters, dominant publications and regions in the research field, as well as important directions for further studies. The clustering of the conceptual landscape under study revealed seven keyword-based clusters and their interconnections, highlighting research priorities. It was established that, despite significant progress in the theoretical development of the circular economy from an interdisciplinary perspective, organizational and economic tools—particularly accounting and reporting—remain underexplored. The findings indicate the significant potential of accounting and reporting, which must be considered in the training of socially responsible accountants, financiers, and managers. The study emphasizes the need for further adaptation of accounting and reporting to meet the requirements of the circular economy, thereby contributing to achieving the Sustainable Development Goals.
Ključne besede: circular economy, accounting, reporting, sustainability reports, sustainable development, social responsibility, bibliometric analysis
Objavljeno v RUNG: 14.05.2025; Ogledov: 138; Prenosov: 2
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3. A time-evolving optimization model for an intermodal distribution supply chain network : a case study at a healthcare companySara Johansson, My Westberg, 2016, magistrsko delo Opis: Enticed by the promise of larger sales and better access to customers, consumer goods compa- nies (CGCs) are increasingly looking to evade traditional retailers and reach their customers directly–with direct-to-customer (DTC) policy. DTC trend has emerged to have major im- pact on logistics operations and distribution channels. It oers significant opportunities for CGCs and wholesale brands to better control their supply chain network by circumventing the middlemen or retailers. However, to do so, CGCs may need to develop their omni-channel strategies and fortify their supply chains parameters, such as fulfillment, inventory flow, and goods distribution. This may give rise to changes in the supply chain network at all strategic, tactical and operational levels.
Motivated by recent interests in DTC trend, this master thesis considers the time-evolving supply chain system of an international healthcare company with preordained configuration. The input is bottleneck part of the company’s distribution network and involves 20% ≠ 25% of its total market. A mixed-integer linear programming (MILP) multiperiod optimization model is developed aiming to make tactical decisions for designing the distribution network, or more specifically, for determining the best strategy for distributing the products from manufacturing plant to primary distribution center and/or regional distribution centers and from them to customers. The company has got one manufacturing site (Mfg), one primary distribution center (PDP) and three dierent regional distribution centers (RDPs) worldwide, and the customers can be supplied from dierent plants with various transportation modes on dierent costs and lead times. The company’s motivation is to investigate the possibility of reduction in distribution costs by in-time supplying most of their demand directly from the plants. The model selects the best option for each customer by making trade-os among criteria involving distribution costs and lead times. Due to the seasonal variability and to account the market fluctuability, the model considers the full time horizon of one year.
The model is analyzed and developed step by step, and its functionality is demonstrated by conducting experiments on the distribution network from our case study. In addition, the case study distribution network topology is utilized to create random instances with random parameters and the model is also evaluated on these instances. The computational experiments on instances show that the model finds good quality solutions, and demonstrate that significant cost reduction and modality improvement can be achieved in the distribution network. Using one-year actual data, it has been shown that the ratio of direct shipments could substantially improve. However, there may be many factors that can impact the results, such as short-term decisions at operational level (like scheduling) as well as demand fluctuability, taxes, business rules etc. Based on the results and managerial considerations, some possible extensions and final recommendations for distribution chain are oered.
Furthermore, an extensive sensitivity analysis is conducted to show the eect of the model’s parameters on its performance. The sensitivity analysis employs a set of data from our case study and randomly generated data to highlight certain features of the model and provide some insights regarding its behaviour.
Ključne besede: optimization, mixed-integer linear programming, supply chain, distribution network, sensitivity analysis
Objavljeno v RUNG: 14.04.2025; Ogledov: 323; Prenosov: 2
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4. Designing the intermodal multiperiod transportation network of a logistic service provider company for container managementTobias Sahlin, 2016, magistrsko delo Opis: Lured by the promise of bigger sales, companies are increasingly looking to raise the volume of international trade. Consequently, the amount of bulk products carried in containers and transported overseas exploded because of the flexibility and reliability of this type of transportation. However, minimizing the logistics costs arising from the container flow management across different terminals has emerged asa major problem that companies and affiliated third-party logistics firms face routinely.
The empty tankcontainer allocation problem occurs in the context of intermodal distribution systems management and transportation operations carried out by logistic service provider companies. This paper considers the time-evolving supply chain system of an international logistic service provider company that transports bulk products loaded in tank containers via road, rail and sea. In such system, unbalanced movements of loaded tank containers forces the company to reposition empty tank containers. The purpose of this paper is to develop a mathematical model that supports tactical decisions for flow management of empty tank containers. The problem involves dispatching empty tank containers of various types to the meet on-time delivery requirements and repositioning the other tank containers to storage facilities, depots and cleaning stations. To this aim, a mixed-integer linear programming (MILP) multiperiod optimization model is developed.
The model is analyzed and developed step by step, and its functionality is demonstrated by conducting experiments on the network from our case study problem, within the boarders of Europe. The case study constitutes three different scenarios of empty tank container allocation. The computational experiments show that the model finds good quality solutions, and demonstrate that cost and modality improvements can be achieved in the network The sensitivity analysis employs a set of data from our case study and randomly selected data to highlight certain features of the model and provide some insights regarding the model’s behavior.
Ključne besede: supply chain, distribution network, repositioning, intermodal transport, sensitivity analysis
Objavljeno v RUNG: 14.04.2025; Ogledov: 1446; Prenosov: 2
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5. Characterization of brown carbon absorption in different European environments through source contribution analysisHector Navarro-Barboza, Jordi Rovira, Vincenzo Obiso, Andrea Pozzer, Marta Via, Andrés Alastuey, Xavier Querol, Jesús Yus-Díez, Matic Ivančič, Martin Rigler, 2025, izvirni znanstveni članek Opis: Brown carbon (BrC) is a fraction of organic aerosol (OA) that absorbs radiation in the ultraviolet and short visible wavelengths. Its contribution to radiative forcing is uncertain due to limited knowledge of its imaginary refractive index (k). This study investigates the variability of k for OA from wildfires, residential, shipping, and traffic emission sources over Europe. The Multiscale Online Nonhydrostatic Atmosphere Chemistry (MONARCH) model simulated OA concentrations and source contributions, feeding an offline optical tool to constrain k values at 370 nm. The model was evaluated against OA mass concentrations from aerosol chemical speciation monitors (ACSMs) and filter sample measurements, as well as aerosol light absorption measurements at 370 nm derived from an Aethalometer™ from 12 sites across Europe. Results show that MONARCH captures the OA temporal variability across environments (regional, suburban, and urban background). Residential emissions are a major OA source in colder months, while secondary organic aerosol (SOA) dominates in warmer periods. Traffic is a minor primary OA contributor. Biomass and coal combustion significantly influence OA absorption, with shipping emissions also notable near harbors. Optimizing k values at 370 nm revealed significant variability in OA light absorption, influenced by emission sources and environmental conditions. Derived k values for biomass burning (0.03 to 0.13), residential (0.008 to 0.13), shipping (0.005 to 0.08), and traffic (0.005 to 0.07) sources improved model representation of OA absorption compared to a constant k. Introducing such emission source-specific constraints is an innovative approach to enhance OA absorption in atmospheric models.
Ključne besede: aerosols, brown carbon, source contribution analysis
Objavljeno v RUNG: 04.03.2025; Ogledov: 660; Prenosov: 6
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6. Modeling of solvent role in protein folding experiments : dissertationKnarik Yeritsyan, 2025, doktorska disertacija Opis: The Zimm-Bragg (ZB) model serves as a fundamental framework for elucidating conformational transitions in biopolymers, offering simplicity and efficacy in processing experimental data. This study provides a comprehensive review of the Zimm-Bragg model and its Hamiltonian formulation, with particular emphasis on incorporating water interactions and chain size effects into the computational framework. We propose a modified ZB model that accounts for water-polypeptide interactions, demonstrating its ability to describe phenomena such as cold denaturation and helix-coil transitions. In the realm of NanoBioTechnologies, the manipulation of short polypeptide chains is commonplace. Experimental investigation of these chains in vitro often relies on techniques like Circular Dichroism (CD) and timeresolved infrared spectroscopy. Determining interaction parameters necessitates processing the temperature dependence of the normalized degree of helicity through model fitting. Leveraging recent advancements in the Hamiltonian formulation of the Zimm and Bragg model, we explicitly incorporate chain length and solvent effects into the theoretical description. The resulting expression for helicity degree adeptly fits experimental data, yielding hydrogen bonding energies and nucleation parameter values consistent with field standards. Differential Scanning Calorimetry (DSC) stands as a potent tool for measuring the specific heat profile of materials, including proteins. However, relating the measured profile to microscopic properties requires a suitable model for fitting. We propose a novel algorithm for processing DSC experimental data based on the ZB theory of protein folding in water. This approach complements the classical two-state paradigm and provides insights into protein-water and intraprotein hydrogen bonding energies. An analytical expression for heat capacity, considering water interaction, is derived and successfully applied to fit numerous DSC experimental datasets reported in the literature. Additionally, we compare this approach with the classical two-state model, demonstrating its efficacy in fitting DSC data. Furthermore, we have developed and launched a free online tool for processing CD and DSC experimental data related to protein folding, aiming to support scientific research.
Ključne besede: Zimm-Bragg model, conformational transitions, helix-coil transitions, cold denaturation, circular dichroism, differential scanning calorimetry, protein folding, water-protein interaction, hydrogen bonding energy, degree of helicity, short polypeptide chains, protein heat capacity, protein data analysis, dissertations
Objavljeno v RUNG: 27.01.2025; Ogledov: 835; Prenosov: 13
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10. Uncertainty modeling and stability assessment of minimum spanning trees in network designAhmad Hosseini, 2024, izvirni znanstveni članek Opis: The Minimum Spanning Tree (MST) problem in networks focuses on finding efficient routes, with applications in transportation, logistics, telecommunications, and more. However, catastrophes can make these networks uncertain, requiring robust computational models for decision-making. This paper introduces an uncertainty theory-based model to analyze the stability of MSTs in uncertain networks. By incorporating reliability and risk variables, we assess the robustness of uncertain MSTs (UMSTs) and address the challenge of computing link tolerances, which define the range within which network links can vary without compromising MST optimality. This study proposes computational formulations to systematically calculate these tolerances, offering a more efficient alternative to traditional re-optimization methods.
Ključne besede: operations research, transportation, sensitivity analysis, uncertainty, reliability
Objavljeno v RUNG: 03.12.2024; Ogledov: 963; Prenosov: 7
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