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Fusion behavior of pure magnesium during selective laser melting
No full textThis study examined the melting behavior and flowability of pure magnesium during selective laser melting. The potential to increase product density was also investigated. Various combinations of manufacturing parameters were considered. The laser power was gradually increased in different machine runs, with different scanning speeds for each run to vary the energy density (ED). The laser power ranged from 10 W to 75 W, and the scanning speed ranged from 100 mm/s to 800 mm/s. Lower laser powers resulted in poor melting, while higher laser powers produced better melting, with significant differences even when the ED was the same. High EDs between 3.50 J/mm² and 4.30 J/mm² led to a lack of melting at low laser power and to an unstable melt pool with significant spattering at high laser power. In contrast, moderate EDs in the range of 1.40 J/mm² to 2.90 J/mm² resulted in better density at high laser power. Higher scanning speeds helped to avoid the formation of a dense smog cloud and provided sufficient energy in a short time with the aid of higher laser power. Therefore, increasing both laser power and scanning speed improved melting performance and increased product density. The relative product density ranged from 80 % to 96.5 %. Reducing the layer thickness from 50 µm to 25 µm at a laser power of 40 W resulted in the formation of a well-formed melt pool in some areas and significant melt spattering in others, which led to a deterioration in density.V raziskavi smo proučevali obnašanje taljenja čistega magnezija in pretočnost njegove taline med selektvinim laserskim taljenjem. Raziskali smo tudi vpliv različnih kombinacij procesnih parametrov na povečanje gostote izdelka. Moč laserja smo postopoma povečevali in pri tem spreminjali hitrosti skeniranja za vsako serijo izdelkov, s čimer smo vplivali na vnos energije v talilni process (ED). Moč laserja se je gibala od 10 W do 75 W, hitrost skeniranja pa od 100 mm/s do 800 mm/s. Z nižjimi močmi laserja nismo dosegli zadovoljivega taljenja materiala, medtem ko so višje moči laserja povzročile boljše taljenje, z znatnimi razlikami tudi pri enakih vnosih energije - ED. Visoka energijska gostota - ED med 3,50 J/mm² in 4,30 J/mm² je povzročila pomanjkljivo taljenje pri nizki moči laserja oziroma nestabilen talilni bazen z znatnim pršenjem materiala pri visoki moči laserja. Nasprotno pa so zmerne ED v območju od 1,40 J/mm² do 2,90 J/mm² povzročile boljšo gostoto pri visoki moči laserja. Višje hitrosti skeniranja so pomagale preprečiti nastanek gostega oblaka smoga in s pomočjo večje laserske moči zagotovile zadostno energijo v kratkem času. Zato je povečanje tako laserske moči kot hitrosti skeniranja izboljšalo učinkovitost taljenja in povečalo gostoto vzorca. Relativna gostota vzorcev se je gibala od 80 % do 96,5 %. Zmanjšanje debeline plasti s 50 µm na 25 µm pri laserski moči 40 W je na nekaterih območjih povzročilo nastanek dobro oblikovanega bazena taline, na drugih pa znatno brizganje taline, kar je povzročilo poslabšanje gostote
Integrated design, simulation, and experimental validation of advanced cellular metamaterials
Get PDFCellular metamaterials offer supreme properties for engineering, medicine, and defence, but their transition to industrial use faces design, fabrication, and characterisation challenges. This review provides an overview of 20 years of advancements in cellular structures, from open-cell foams to triply periodic minimal surfaces (TPMS), presenting novel fabrication techniques (e.g., explosive compaction for UniPore structures) and demonstrating validated computational models for optimising graded auxetic and hybrid TPMS lattices. The study indicates that porosity and base material primarily govern energy absorption, with closed-cell foams and TPMS outperforming other geometries. Additive manufacturing enables spatially graded designs with tailored mechanical properties. This work accelerates the development of next-generation metamaterials for crash absorption, blast protection, and biomedical devices.Celični metamateriali nudijo vrhunske lastnosti za inženirstvo, medicino in obrambo, vendar njihov prehod v industrijsko uporabo otežujejo izzivi pri razvoju, izdelavi in karakterizaciji. Ta pregled ponuja povzetek 20 let napredka na področju celičnih struktur, od pen z odprtimi celicami do struktur s trojno periodičnimi minimalnimi površinami (TPMS). Predstavlja nove tehnike izdelave (npr. eksplozijsko varjenje za strukture UniPore) in prikazuje validirane računalniške modele za optimizacijo gradiranih avksetičnih in hibridnih TPMS metamaterialov. Študija kaže, da na absorpcijo energije vplivata predvsem poroznost in osnovni material, pri čemer se zaprto-celične pene in TPMS strukture izkažejo bolje kot druge geometrije. Dodajalne tehnologije omogočajo prostorsko gradiranje s prilagojenimi mehanskimi lastnostmi. To delo pospešuje razvoj metamaterialov naslednje generacije za absorpcijo trkov, zaščito pred eksplozijami in biomedicinske naprave
Identification and prioritization of barriers to the implementation of an asset management system in the healthcare sector using a Delphi-AHP approach
Get PDFPurpose – An effective asset management system (AMS) is essential for healthcare organizations looking to
maximize value and performance while minimizing risk and cost. This study aims to identify and evaluate the
barriers to AMS adoption and evaluate them from a healthcare perspective.
Design/methodology/approach – The study is based on a combination of the Delphi method and the analytic
hierarchy process (AHP) with 30 participants from various Slovenian healthcare organizations. Through
iterative consensus and prioritization, the Delphi-AHP process resulted in 23 validated barriers, ranked
according to their perceived importance for AMS implementation.
Findings – The resultsidentified key barriersto implementing AMS in healthcare organizations and categorized
them into five dimensions: strategic, human resources, contextual, structural and procedural. The highest ranked barriers were deficient leadership, a shortage of qualified personnel and workforce overload. This
indicates that strategic alignment and organizational capacity are perceived as the most critical obstacles to
adopting AMS.
Originality/value – Thisstudy advancesthe existing literature by addressing a critical gap and providing deeper
insight into the factors that impede the successful implementation of AMS in healthcare settings, a domain
where empirical evidence remains limited
Pripravljenost na kibernetsko varnost v evro-sredozemski regiji
Get PDFPurpose:
The article presents a comparison of national cybersecurity strategies and
global indices in 12 Euro-Mediterranean countries to determine the extent to
which they align with international standards and the presence of any map
readiness disparities. A harmonised regional agenda to strengthen collective
resilience is proposed.
Design/Methods/Approach:
The article presents a comparative literature review of national strategies,
the International Telecommunication Union’s (ITU) Global Cybersecurity Index
(GCI) and the Cybersecurity Capacity Maturity Model (CMM). Equal weight is
given to the ITU-GCI pillars and CMM indicators, while the European Union
Agency for Cybersecurity (ENISA) and national reports provide the qualitative
context.
Findings:
European Union (EU) member states show mature legal, organisational and
capacity measures, while several non-European Union (non-EU) Mediterranean
states encounter fragmented laws and resource gaps. Common patterns include
institutionalised Computer Emergency Response Team/Computer Security
Incident Response Team (CERT/SCIRT) functions and a convergence on
international frameworks, yet actionable gaps persist in enforcement and crossborder coordination.
Research Limitations/Implications:
The findings are limited by the asynchronous index updates and the
countries’ varying national cybersecurity strategy (NCSS) formats. Future work
could track implementation metrics and refresh comparative baselines as new
index data emerge.
Practical Implications:
Priority must be given to legal interoperability, baseline incident reporting,
and shared regional exercises to minimise weakest-link risk in interconnected
infrastructures.
Originality/Value:
The first structured comparison of Euro-Mediterranean cybersecurity
readiness to integrate global indices with NCSS analysis.Namen: Članek predstavlja primerjavo nacionalnih strategij kibernetske varnosti in globalnih indeksov v 12 evro-sredozemskih državah z namenom ugotoviti usklajenost z mednarodnimi standardi in ali med državami obstajajo razlike v pripravljenosti. Predlagan je usklajen regionalni program za krepitev skupne odpornosti. Metode: Članek predstavlja primerjalni pregled literature nacionalnih strategij, globalni indeks kibernetske varnosti (GCI) Mednarodne telekomunikacijske zveze (ITU) in model zrelosti zmogljivosti kibernetske varnosti (CMM). Stebri ITU-GCI in kazalniki CMM so enakovredno uteženi, poročila Agencije Evropske unije za kibernetsko varnost (ENISA) in nacionalni dokumenti pa zagotavljajo kvalitativni kontekst. Ugotovitve: Države članice Evropske unije (EU) izkazujejo zrele pravne, organizacijske in zmogljivostne ureditve, medtem ko se nekatere sredozemske države izven EU soočajo z razdrobljenimi pravnimi okviri in pomanjkanjem virov. Prisotna sta institucionalizacija nacionalnih odzivnih centrov za kibernetsko varnost/ ekip strokovnjakov, ki zagotavlja hiter in učinkovit odziv na varnostne incidente (Computer Emergency Response Team/Computer Security Incident Response Team (CERT/CSIRT)) ter približevanje mednarodnim okvirjem, vrzeli pa ostajajo pri izvrševanju in čezmejnem usklajevanju. Omejitve: Rezultate omejujejo neusklajene posodobitve indeksov in raznoliki formati nacionalnih strategij kibernetske varnosti (NCSS). Nadaljnje delo bi lahko spremljalo kazalnike izvajanja in posodabljalo primerjalna izhodišča ob novih objavah indeksov. Praktična uporabnost: Prednost je treba dati pravni interoperabilnosti, osnovnemu poročanju o incidentih in skupnim regionalnim vajam, da bi zmanjšali tveganje najšibkejšega člena v regionalni verigi odpornosti. Izvirnost/Pomembnost prispevka: Gre za prvo strukturirano primerjavo pripravljenosti na kibernetsko varnost v evro-sredozemski regiji, ki združuje globalne indekse in analizo NCSS
A multi-task deep learning approach for landslide displacement prediction with applications in early warning systems
Get PDFAccurate landslide displacement prediction is important for the construction of reliable landslide early warning systems (LEWS). Recently, deep neural networks have become the dominant approach for landslide displacement modeling. However, we show that focusing solely on low prediction residuals is not perfectly aligned with the goals of LEWS, where the emphasis is on precise forecasts near the warning threshold. This can result in poor efficiency of threshold-based warning prediction. We propose a multi-task approach to model training, where auxiliary targets are used to optimize the model towards the performance relevant for LEWS. The methodology is validated using the data from the deep-seated Urbas landslide in north-western Slovenia, which has been monitored by GNSS since 2019. Developing a displacement prediction model for Urbas is a step towards extending the existing wire-based mechanical alarm system. We employ a convolutional neural network for day-ahead displacement prediction using recent landslide activity, hydrometeorological measurements and seismological data. The proposed multi-task model retains a competitive score for warning prediction while achieving a significantly lower mean absolute error compared to the reference models. The proposed methodology is generally applicable and has the potential to improve the efficiency of landslide modeling in the context of LEWS
Vpliv pandemije Covid-19 na klinično-patološke značilnosti in razširjenost raka debelega črevesa in danke ob postavitvi diagnoze in izbor zdravljenja
Get PDFPredvideno ravnanje z radioaktivnimi odpadki in izrabljenim gorivom iz JEK2 ter s tem povezanimi stroški
Get PDFAn essential early phase of any new nuclear power plant (NPP) project is the drafting and preparation of a radioactive waste management strategy. The paper outlines the major steps in such a strategy, presented in a case study approach for the new NPP project in Krško (the JEK2 project). The paper includes analyses of the options and strategies for radioactive waste (RAW) and spent nuclear fuel (SNF) management. This article presents a proposed management plan for the RAW and SNF expected to be produced during the operation and decommissioning of JEK2, together with an assessment ofthe anticipated decommissioning and waste management costs. The document examines further the existing financing framework for radioactive waste management in Slovenia, which is regulated legally for the current nuclear facilities. A similar approach is planned for JEK2, including the expansion of the existing and planned facilities for waste handling and storage. Accordingly, additional financial resources will be required through contributions to the national decommissioning and disposal fund. An analysis was therefore conducted, to estimate the scale of the additional contributions needed to ensure adequate funding for the new NPP project in Krško.Ključen del priprav projekta JEK2 predstavljajo analize, potrebne za dolgoročno, varno in učinkovito načrtovanje ravnanja z radioaktivnimi odpadki (RAO), izrabljenim gorivom (IG) in razgradnjo elektrarne po koncu obratovanja. Članek na primeru projekta JEK2 predstavi glavne elemente takšne strategije. Vključuje pregled možnosti in pristopov k ravnanju z RAO in IG, za katere se pričakuje, da bodo nastali med obratovanjem in razgradnjo JEK2, skupaj z oceno predvidenih stroškov. Dokument dodatno preučuje obstoječi finančni okvir za ravnanje z radioaktivnimi odpadki v Sloveniji, ki je zakonsko urejen za obstoječe jedrske objekte. Podoben pristop je predviden za JEK2, vključno s širitvijo obstoječih in načrtovanih objektov za ravnanje z odpadki, njihovo skladiščenje in odlaganje. Ekonomski vidik financiranja ravnanja z RAO temelji na uveljavljeni praksi zbiranja sredstev prek namenskega sklada, ki deluje kot mehanizem za upravljanje finančnih virov
Raziskovanje različnih oblik razvoja majhnih mest v srednji in vzhodni Evropi
Get PDFSmall town research represents a dominant part in urban geography. Being a transitional settlement type between urban and rural landscapes, it is important to define the roles of small towns regarding economy, services and infrastructure, recreation, or simply by their representations and identity. In this article, we aim to provide an insight into small town research in Central Eastern Europe and beyond, based on a 2024 summer school, focusing on the changing development paths of small towns.Raziskovanje malih mest predstavlja pomemben del urbane geografije. Ker gre za prehodni tip naselja med mestnimi in podeželskimi krajinami, je pomembno opredeliti vloge malih mest glede na gospodarstvo, storitve in infrastrukturo, rekreacijo ter njihovo reprezentacijo in identiteto. V tem članku podajamo vpogled v raziskovanje malih mest v srednji in vzhodni Evropi ter širše na podlagi poletne šole iz leta 2024 in s poudarkom na spreminjajočih se razvojnih poteh malih mest