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Abstract: The content of this paper presents the research results of a three-year research project in which a multi-criteria evaluation model (according to the DEX methodology) was developed for the evaluation of three different food sectors (represented by a cattle breeding chain, a pig farming chain, and a milk production chain) with added value in Slovenia. Indicators for the assessment of the economically, socially, and environmentally sustainable development of food chains were taken into account. The data for the analysis, such as prices and costs of food, wage levels by sector, food miles and others, were obtained from various public services between 2020 and 2023. The final qualitative assessment of the food sectors was uniform (“average”), while the longest analysis of the results using the plus-minus-1 analysis method showed the reasons for such an assessment in individual sectors (such as the ratio between the price of agricultural products and the price of agricultural inputs is poor, the ratio between average gross salary in the individual food sector and gross salary in the agricultural sector is poor, etc.). In addition to the results already mentioned, recommendations or suggestions for building a sustainable food chain were made using the results of the modelling. The research results contributed to a better understanding of the importance of stable relationships between different groups of indicators and later showed their importance for improving the functioning of agri-food chains. The results of the research will help various stakeholders (such as the agricultural advisory service, decision-makers at the level of agricultural policy, researchers in further analyses, and especially the international professional public interested in various case studies from EU countries) to further analyse and plan for the organisation of the agricultural sector.
Keywords: food sectors, value added, DEX methodology, plus-minus-1 analysis, Slovenia
Published in DKUM: 29.11.2024; Views: 0; Downloads: 2
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Abstract: The static and dynamic loading capacities of components depend on the stress level to which the material is exposed. The fatigue behavior of materials manufactured using additive technology is accompanied by a pronounced scatter between the number of cycles at the same stress level, which is significantly greater than the scatter from a material with the same chemical composition, e.g., AISI 316L, but produced by rolling or forging. An important reason lies in the fact that fatigue cracks are initiated almost always below the material surface of the loaded specimen. Thus, in the article, assuming that a crack will always initiate below the surface, we analyzed the fatigue behavior of specimens with the same bearing cross section but with a different number of bearing rods. With a larger number of rods, the circumference around the supporting part of the rods was 1.73 times larger. Thus, experimental fatigue of specimens with different sizes showed that the dynamic loading capacity of components with a smaller number of bars is significantly greater and can be monitored by individual stress levels. Although there are no significant differences in loading capacity under static and low-cycle loading of materials manufactured with additive technologies, in high-cycle fatigue it has been shown that the ratio between the circumference and the loading cross section of tensile-loaded rods plays an important role in the lifetime. This finding is important for setting a strategy for manufacturing components with additive technologies. It shows that a better dynamic loading capacity can be obtained with a larger loading cross section.
Keywords: AISI 316L stainless steel, additive manufacturing, FEM, high-cycle fatigue, fractography analysis
Published in DKUM: 25.11.2024; Views: 0; Downloads: 6
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Abstract: Many details of glucose-stimulated intracellular calcium changes in [beta] cells during activation, activity, and deactivation, as well as their concentration-dependence, remain to be analyzed. Classical physiological experiments indicated that in islets, functional differences between individual cells are largely attenuated, but recent findings suggest considerable intercellular heterogeneity, with some cells possibly coordinating the collective responses. To address the above with an emphasis on heterogeneity and describing the relations between classical physiological and functional network properties, we performed functional multicellular calcium imaging in mouse pancreas tissue slices over a wide range of glucose concentrations. During activation, delays to activation of cells and any-cell-to-first-responder delays are shortened, and the sizes of simultaneously responding clusters increased with increasing glucose concentrations. Exactly the opposite characterized deactivation. The frequency of fast calcium oscillations during activity increased with increasing glucose up to 12 mM glucose concentration, beyond which oscillation duration became longer, resulting in a homogenous increase in active time. In terms of functional connectivity, islets progressed from a very segregated network to a single large functional unit with increasing glucose concentration. A comparison between classical physiological and network parameters revealed that the first-responders during activation had longer active times during plateau and the most active cells during the plateau tended to deactivate later. Cells with the most functional connections tended to activate sooner, have longer active times, and deactivate later. Our findings provide a common ground for recent differing views on [beta] cell heterogeneity and an important baseline for future studies of stimulus-secretion and intercellular coupling. NEW & NOTEWORTHY: We assessed concentration-dependence in coupled [beta] cells, degree of functional heterogeneity, and uncovered possible specialized subpopulations during the different phases of the response to glucose at the level of many individual cells. To this aim, we combined acute mouse pancreas tissue slices with functional multicellular calcium imaging over a wide range from threshold (7 mM) and physiological (8 and 9 mM) to supraphysiological (12 and 16 mM) glucose concentrations, classical physiological, and advanced network analyses.
Keywords: beta cells, calcium imaging, glucose-dependence, network analysis
Published in DKUM: 15.10.2024; Views: 0; Downloads: 6
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Abstract: The stay-at-home restrictions to control the spread of COVID-19 led to unparalleled sudden change in daily life, but it is unclear how they affected urban crime globally. We collected data on daily counts of crime in 27 cities across 23 countries in the Americas, Europe, the Middle East and Asia. We conducted interrupted time series analyses to assess the impact of stay-at-home restrictions on different types of crime in each city. Our findings show that the stay-at-home policies were associated with a considerable drop in urban crime, but with substantial variation across cities and types of crime. Meta-regression results showed that more stringent restrictions over movement in public space were predictive of larger declines in crime.
Keywords: criminology, crime, pandemic, restrictions, stay-at-home, analysis
Published in DKUM: 03.10.2024; Views: 0; Downloads: 1
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Abstract: Metals with certain porosity are a new class of materials with extremely low density and a unique combination of excellent mechanical, thermal, electrical, and biocompatible properties. Absorption of impact and shock energy, dust and fluid filtration, construction materials, and most importantly, biocompatible implants are all potential applications for metallic foams. An orthopaedic implant made of metallic foam can provide an open-cell structure that allows for the ingrowth of new bone tissue and the transport of body fluids. Due to its strong biocompatibility and stable fixation between the implant and human bone, titanium foam has recently received much attention as an implant material. Finite element modelling is a suitable method to obtain an efficiently designed implant. Accurate finite element analyses depend on the precision before implementation as well as the functionality of the material properties employed. Since the mechanical performances of titanium foam and solid titanium are different, a constitutive model for porous metal is required. The model of Deshpande and Fleck in the finite element analysis software ABAQUS is used to describe the compressive and flexural deformation properties of titanium foam with 63.5% porosity. The finite element simulation results were compared with the practical mechanical properties obtained by compression testing of the foam. Finally, the material modelling was used to investigate the stress distributions on the dental implant system.
Keywords: finite element analysis, ABAQUS, titanium foam, sintering, dental implant, material modeling, mechanical properties, bending, compressing
Published in DKUM: 25.09.2024; Views: 0; Downloads: 3
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