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1.
Comparison of the mechanical properties of hardfacings made by standard coated stick electrodes and a newly developed rectangular stick electrode
Edvard Bjelajac, Andrej Skumavc, Gorazd Lojen, Mirza Manjgo, Tomaž Vuherer, 2024, izvirni znanstveni članek

Opis: Cladding with a stick electrode is one of the oldest arc processes for adding a deposit on a base material. The process is suitable for outdoor working, but the disadvantages are low productivity and large dilution rates. In this work, a simple solution is proposed, which would enable cladding of a larger area with one pass and decrease the dilution rate at the same time—a new type of electrode was developed, exhibiting a rectangular cross-section instead of a round one. Hardfacings, welded with E Fe8 electrodes according to EN 14 700 Standard were welded on mild steel S355 J2 base material with three different coated stick electrodes. The first one was a commercially available, standard, round hardfacing electrode, the second was the same, but with a thinner coating, and the third one was a newly developed rectangular electrode. All three types had equal cross-sections of the metallic core and the same type of coating. Manufacturing of the rectangular electrodes in the laboratory is explained briefly. One- and multi-layer deposits were welded with all three types. Differences were observed in the arc behavior between the round and rectangular electrodes. With the rectangular electrode, the microstructure of the deposit was finer, penetration was shallower, and dilution rates were lower, while the hardness was higher, residual stresses predominantly compressive, and the results of instrumented Charpy impact tests and fracture mechanics tests were better.
Ključne besede: hardfacing, dilution rate, hardness, Charpy impact toughness, residual stress, fracture toughness
Objavljeno v DKUM: 14.05.2024; Ogledov: 121; Prenosov: 8
.pdf Celotno besedilo (10,82 MB)
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2.
The impact of psychological interventions with elements of mindfulness on burnout and well-being in healthcare professionals : a systematic review
Polona Selič-Zupančič, Zalika Klemenc-Ketiš, Sara Onuk Tement, 2023, pregledni znanstveni članek

Opis: Background Healthcare professionals are highly likely to experience various causes of work-related stress, which often leads to burnout. This became even more obvious during the Covid-19 pandemic. This systematic review aimed to analyze articles where psychological interventions with elements of mindfulness (PIM) were used to support healthcare professionals to foster well-being and reduce burnout levels. Compared to other recently published reviews, it is unique, due to its focus on a wide group of healthcare professionals, a broader selection of psychological interventions, and the evaluation of any sustained effects. Methods Systematic searches were carried out in February 2021 with different combinations of Boolean operators within six electronic databases: PubMed, EBSCOhost, MEDLINE, PsycArticles, Cochrane Library, JSTOR and Cobiss. We included articles that had been published in the last ten years (2011 to 2021) and which reported on original research focused on evaluating the influence of PIM on healthcare professionals. MERSQI was used to assess the quality of the included studies. Results Of 1315 identified studies, 15 were included in this systematic review. Regardless of the specific type, duration and setting (individual vs group) of PIM applied, the results demonstrated a positive impact on well-being and burnout in participating healthcare professionals. The most studied interventions involved MBSR (mindfulness-based stress reduction) and other mindfulness training programmes, in online as well as in-person versions. Conclusion Given the new reality with the presence of the SARS-Cov-2 virus, it is of the utmost importance to offer feasible, effective interventions for burnout reduction to vulnerable groups of healthcare professionals. By focusing on their needs, several key aspects of burnout and mindfulness could be efficiently improved; this review demonstrates that short, online interventions could be as effective as longer, in-person ones.
Ključne besede: mindfulness, burnout, perceived stress, well-being, Covid-19, MBSR
Objavljeno v DKUM: 26.03.2024; Ogledov: 106; Prenosov: 3
.pdf Celotno besedilo (1,14 MB)
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3.
The role of oxidative stress in kidney injury
Nejc Piko, Sebastjan Bevc, Radovan Hojs, Robert Ekart, 2023, pregledni znanstveni članek

Opis: Acute kidney injury and chronic kidney disease are among the most common non-communicable diseases in the developed world, with increasing prevalence. Patients with acute kidney injury are at an increased risk of developing chronic kidney disease. One of kidney injury’s most common clinical sequelae is increased cardiovascular morbidity and mortality. In recent years, new insights into the pathophysiology of renal damage have been made. Oxidative stress is the imbalance favoring the increased generation of ROS and/or reduced body’s innate antioxidant defense mechanisms and is of pivotal importance, not only in the development and progression of kidney disease but also in understanding the enhanced cardiovascular risk in these patients. This article summarizes and emphasizes the role of oxidative stress in acute kidney injury, various forms of chronic kidney disease, and also in patients on renal replacement therapy (hemodialysis, peritoneal dialysis, and after kidney transplant). Additionally, the role of oxidative stress in the development of drug-related nephrotoxicity and also in the development after exposure to various environmental and occupational pollutants is presented.
Ključne besede: acute kidney injury, acute tubular necrosis, chronic kidney disease, oxidative stress, reactive oxygen species
Objavljeno v DKUM: 19.03.2024; Ogledov: 119; Prenosov: 21
.pdf Celotno besedilo (1007,69 KB)
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4.
Honey, there´s something on my mind --- : adverse consequences of negative and positive work rumination on attention to the partner, and the advantage of talking about it
Julia Schoellbauer, Sara Tement, Christian Korunka, 2023, izvirni znanstveni članek

Opis: In the contemporary 24/7 working society, the separation of work and private life is increasingly turning into an unrealizable ideal. Ruminating about work outside the work context lets work spill over into private lives and afects the dynamics of workers’ private relationships. Although negative work rumination was linked to couples’ reduced relationship satisfaction, little is known about the mechanism of action and the impact of positive work rumination. Drawing on the load theory of selective attention, we hypothesize that both negative and positive work rumination occupy attentional resources and thus reduce workers’ attention to the partner on the same day. Lower levels of attention to the partner, in turn, should relate to lower levels of both partners’relationship satisfaction. However, sharing the work-related thoughts with the partner might support the resolution of the work issue the worker is ruminating about, which releases attentional resources and thus bufers the negative association between rumination and attention to the partner. We conducted a daily diary study and the fndings based on 579 daily dyadic observations from 42 dualearner couples support the proposed cognitive spillover-crossover mechanism and the bufer mechanism of thought-sharing. We conclude that negative and positive work rumination takes up scarce attentional resources and thus jeopardizes relationship quality. However, sharing thoughts with one’s partner seems to be a useful strategy for couples to maintain or even increase their relationship satisfaction in the light of work rumination.
Ključne besede: Diary study, Dyadic research, Relationship quality, Psychological availability, Spillover-crossover, Actor-partner interdependence mode, family conflict, perceptual load, relationship satisfaction, marital, quality, daily-diary, couples, stress, experiences depression, crossover, Psychology
Objavljeno v DKUM: 20.02.2024; Ogledov: 182; Prenosov: 9
.pdf Celotno besedilo (989,06 KB)
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5.
Effect of residual stresses on fatigue strength on the smooth and splined parts of spring torsion bars
Vinko Močilnik, Jožef Predan, Nenad Gubeljak, 2023, izvirni znanstveni članek

Opis: The article discusses the effect of residual stresses on the fatigue strength of torsion bars by using the Dang Van fatigue criterion, at the stress concentration at the root of the tooth and at the smooth part of the torsion bar. Residual compressive stresses were induced on the surface during the technological processes by cold surface rolling and torsional pre-strain (pre-setting) to the plastic range, to increase the elastic linear range and to reduce the stress state during torsional loading. Normally, the stress reduction in the torsion bar at the mounting point is provided by the increased diameter of the splined part, compared to the smooth part of the torsion bar. In the case of a small difference between the diameter of the splined and the smooth parts of the torsion bar, a fatigue crack can be initiated in the notch, which causes the torsion bar to break during operation after a few hundred loading cycles. FEM stress analysis of a torsion bar was performed in the article. The actual residual stresses were measured by the non-destructive X-ray method at the place of stress concentration on the smooth and splined parts with a notch of the torsion bar, and Dang Van’s failure criterion was used to determine the fatigue behavior during torsional loading. Therefore, in the paper, the three methods were combined to determine the optimum lifetime of a torsion bar exposed to the required cyclic torque. The results of the analysis showed that the residual compressive stresses are useful up to a certain limit where the retarded fatigue crack initiation occurred, but a further increase of compressive stress caused an increase of the maximum shear stresses, which, in turn, caused the initiation of fatigue and failure at the splined part of the torsion bar before achieving the required number of cycles.
Ključne besede: Dang Van fatigue criterion, torsion bars, pre-setting, high-cycle fatigue, residual stress
Objavljeno v DKUM: 30.11.2023; Ogledov: 317; Prenosov: 23
.pdf Celotno besedilo (7,29 MB)
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6.
International transmission of conventional and unconventional monetary policy and financial stress shocks from the euro area to Russia
Silvo Dajčman, Alenka Kavkler, Sergey Merzlyakov, Sergey E. Pekarski, Dejan Romih, 2022, izvirni znanstveni članek

Opis: This paper studies the international transmission of the euro area´s monetary policy and financial stress to Russia. The results show that financial stress in the euro area damages Russian economic activity and stock prices, but not its trade balance. The contractionary euro area monetary policy shock decreases Russian GDP, leads to real appreciation of the euro against the Russian rouble, damages Russian stock prices, but does not significantly affect the trade balance between countries. We also found that the Central Bank of the Russian Federation adjusts to monetary policy shocks in the euro area.
Ključne besede: conventional monetary policy, unconventional monetary policy, financial stress, Russia, international transmission
Objavljeno v DKUM: 26.09.2023; Ogledov: 345; Prenosov: 19
.pdf Celotno besedilo (1,85 MB)
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7.
The effect of the Ala16Val mutation on the secondary structure of the manganese superoxide dismutase mitochondrial targeting sequence
Matic Broz, Veronika Furlan, Samo Lešnik, Marko Jukič, Urban Bren, 2022, izvirni znanstveni članek

Opis: Manganese Superoxide Dismutase (MnSOD) represents a mitochondrial protein that scavenges reactive oxygen species (ROS) responsible for oxidative stress. A known single nucleotide polymorphism (SNP) rs4880 on the SOD2 gene, causing a mutation from alanine to valine (Ala16Val) in the primary structure of immature MnSOD, has been associated with several types of cancer and other autoimmune diseases. However, no conclusive correlation has been established yet. This study aims to determine the effect of the alanine to valine mutation on the secondary structure of the MnSOD mitochondrial targeting sequence (MTS). A model for each variant of the MTS was prepared and extensively simulated with molecular dynamics simulations using the CHARMM36m force field. The results indicate that the alanine variant of the MTS preserves a uniform α-helical secondary structure favorable for the protein transport into mitochondria, whereas the valine variant quickly breaks down its α-helix. Thus, the alanine MTS represents the more active MnSOD variant, the benefits of which have yet to be determined experimentally.
Ključne besede: manganese superoxide dismutase, polymorphism rs4880, mutation Ala16Val, molecular dynamics simulations, oxidative stress
Objavljeno v DKUM: 21.08.2023; Ogledov: 293; Prenosov: 10
.pdf Celotno besedilo (5,14 MB)
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8.
Validation of boundary element method for assessment of weld joints accounting for notch stress : magistrsko delo
Rok Skerbiš, 2022, magistrsko delo

Opis: Robust, automated mesh generation on arbitrary weld joint geometries, using finite element method (FEM) is a problematic task. It was previously discovered, that an arbitrary weld joint geometry can be parameterized inside a CAD environment [1], however when it comes to domain discretization and boundary conditions assignment, the parameterized approach becomes too demanding inside FEM. This results in long FEM model preparation times and sometimes in problems with the parametric model itself, which leads to a need for an additional numerical method - boundary element method (BEM), which overcomes this issue and is beneficial in this case. BEM is a numerical method, that in addition to other applications finds a use in the elasto-mechanic problems, where the only concern is the boundary of the considered geometric domain. Since notch stress calculations of weld joints fall into this category, their calculation can be carried out with it. Since there is not much available information on whether or not such calculations are a suitable alternative for the currently used FEM, this thesis had to be confirmed through a structured and step by step procedure. First, a notch mesh quality study has been made, then other entities followed. It was discovered that BEM is applicable to the problem and capable of calculating results with sufficient quality. Furthermore, the parameter driven approach and automated calculation provide for additional advantageous potentials.
Ključne besede: weld joint, boundary element method, finite element method, spatial discretization, notch stress
Objavljeno v DKUM: 02.11.2022; Ogledov: 466; Prenosov: 0
.pdf Celotno besedilo (4,62 MB)

9.
ǂThe ǂimpact of climate change on urban thermal environment dynamics
Igor Žiberna, Nataša Pipenbaher, Daša Donša, Sonja Škornik, Mitja Kaligarič, Lučka Kajfež-Bogataj, Zalika Črepinšek, Jaša Veno Grujić, Danijel Ivajnšič, 2021, izvirni znanstveni članek

Opis: The human population is increasing. The ongoing urbanization process, in conjunction with climate change, is causing larger environmental footprints. Consequently, quality of life in urban systems worldwide is under immense pressure. Here, the seasonal characteristics of Maribor's urban thermal environment were studied from the perspectives of surface urban heat island (SUHI) and urban heat island (UHI) A remote sensing thermal imagery time series and in-situ measurements (stationary and mobile) were combined with select geospatial predictor variables to model this atmospheric phenomenon in its most intensive season (summer). Finally, CMIP6 climate change scenarios and models were considered, to predict future UHI intensity. Results indicate that Maribor's UHI intensity maximum shifted from winter to spring and summer. The implemented generalized additive model (GAM) underestimates UHI intensity in some built-up parts of the study area and overestimates UHI intensity in green vegetated areas. However, by the end of the century, UHI magnitude could increase by more than 60% in the southern industrial part of the city. Such studies are of particular concern, in regards to the increasing frequency of heat waves due to climate change, which further increases the (already present) heat stress in cities across the globe.
Ključne besede: urbanizacija, mestni toplotni otoki, poletni vročinski stres, GAM, CMIP6, urbanisation, urban heat island, summer heat stress
Objavljeno v DKUM: 02.09.2022; Ogledov: 666; Prenosov: 18
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10.
The psychodynamic processes related to the involvement in peacekeeping missions : experiences of Slovenian police officers
Branko Lobnikar, Špela Vesel, Emanuel Banutai, 2011, izvirni znanstveni članek

Opis: Purpose: The purpose of this paper is to review the decade of Slovenian police officer’s experiences with international peacekeeping operations. The main goal of police officers, involved in these missions, is to prevent conflicts between opposite sites, to implement basic agreements, protect humanitarian missions and reinforce policing operations in the conflict area. The purpose of the paper is to acknowledge the lessons learned while planning and implementing further cooperation of Slovenian police officers in peacekeeping (police) operations. The main purpose of the paper is to analyze the consequences of deployment to peacekeeping missions for police officers as well as their family members (partners and children) by analyzing the psychodynamic processes related to the involvement in peacekeeping missions. Design/Methods/Approach: The paper is based on the review of literature. The empirical part of the paper presents the results of the research on a small sample of police officers (n = 36) and their family members (n = 25 partners + 35 children). Findings: Police peacekeepers should be well prepared for different stress situations; they are exposed to various stress factors before, during, and after serving in a mission. That is why training and reintegration programmes are of great importance. We establish that respondents assess that deployment to a peacekeeping mission has a positive and negative impact on the relationships between family members. As many as ¾ of mission members believe deployment can have a positive impact above all in the sense of strengthening the emotional ties between partners, increased mutual trust and strengthening of the partnership. For them, deployment to a peacekeeping mission is a challenge and personal experience, which can change the way they see the world. 2/3 of partners state similar positive impacts and they also believe that there is more trust between the partners after the experience with the peacekeeping mission, they treasure their time together and thus represent bigger support for each other in difficult times. As the most common problem, respondents perceived marital problems and the occurrence of negative feelings among family members (anger, avoidance, judgment ...). A large share of respondents stressed problems with children. 43.8% of respondents also named depression as a problem. Research limitations/implications: The findings are limited to the Slovenian police and their police officer’s experiences, serving in various police peacekeeping missions and their family members. Practical implications: Based on lessons learned this paper complements the results of different surveys of the researched topic. The results cannot be completely generalized, although some findings could also be useful to similar police organizations in Europe. Originality/Value: This paper addresses and explores different small scale surveys, conducted on sampled Slovenian police officers who served in peacekeeping missions and their family members. Findings could be of interest for the general as well as expert audience.
Ključne besede: police, police officer’s family, peacekeeping missions, Slovenia, stress, training and reintegration programmes, SE Europe
Objavljeno v DKUM: 05.05.2020; Ogledov: 1124; Prenosov: 55
.pdf Celotno besedilo (624,54 KB)
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