47 research outputs found

    Low temperature magnetism of KAgF3

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    KAgF3_3 is a quasi one-dimensional quantum antiferromagnet hosting a series of intriguing structural and magnetic transitions. Here we use powder neutron diffraction, μ\muSR spectroscopy, and Density Functional Theory calculations to elucidate the low temperature magnetic phases. Below TN1=29T_{N1}=29K we find that the material orders as an A-type antiferromagnet with an ordered moment of 0.47μB\mu_{\rm B}. Both neutrons and muons provide evidence for an intermediate phase at temperatures TN1<T<TN2T_{N1}<T<T_{N2} with TN266T_{N2}\approx 66 K from a previous magnetometry study. However, the evidence is at the limit of detection and its nature remains an open problem.Comment: 11 pages, 8 figures. Supplementary information is included in a separate fil

    Low-temperature magnetism of KAgF3

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    KAgF3 is a quasi-one-dimensional quantum antiferromagnet hosting a series of intriguing structural and magnetic transitions. Here we use powder neutron diffraction, μSR spectroscopy, and density functional theory calculations to elucidate the low-temperature magnetic phases. Below TN1 = 29 K we find that the material orders as an A-type antiferromagnet with an ordered moment of 0.52 μ B . Both neutrons and muons provide evidence for an intermediate phase at temperatures TN1 < T < TN2 with TN2 ≈ 66 K from a previous magnetometry study. However, the evidence is at the limit of detection and its nature remains an open problem

    Changeability and agility enablers in one-of-a-kind product development and design processes

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    The smart factories that are already beginning to appear employ a completely new approach to product creation. Smart products are uniquely identifiable and know both their current status and alternative routes to achieving their target state. Smart factories allow individual customer requirements to be met, meaning that even one-off items can be manufactured profitably. In smart industry, dynamic business and engineering processes enable last-minute changes to design and production, delivering the ability to respond flexibly to disruptions and failures on behalf of suppliers. This paper presents a case study of product development and design process renovation according to changeability paradigm in one-of-a-kind industrial environment. It demonstrates how integration of changeability with agile design strategies crucially contribute to improve the operations of a highly individualized product development business. Successful management of ‘never-ending’ engineering changes appears to be the most important aspect in this field. Contribution of the presented work is a generalized framework that demonstrates how companies in such specific environments can improve competitiveness through the utilization of changeability concepts. The included case study validated the proposed changeability model and offers valuable insights into how to implement this in practice

    Mechanism and kinetics of CBDA decarboxylation into CBD in hemp

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    Cannabidiol (CBD) is a pharmacologically active ingredient for use in medical, cosmetic, and food products. CBD forms from cannabidiolic acid (CBDA) with the process of decarboxylation by heating cannabis (Cannabis sativa L.) material. During the production of CBD-rich material, decarboxylation should be performed in precise conditions regarding temperature and time. The experiments were performed by heating hemp samples at 100, 110, 120, 130, and 140 °C for 180 min. Materials were sampled every 20 min and cannabinoid content was analyzed using HPLC, followed by calculation of kinetic parameters. Experimental results showed an exponential reduction of CBDA in the samples during heating. CBD simultaneously increased, and after a specific point, CBD started degrading. The optimal conditions were 140 °C for 30 min. At the level of molecular orbitals, reaction steps, and reaction coordinates, along with the corresponding changes in molecular energy, the molecular mechanism of CBDA decarboxylation and CBD formation was described. Computational analysis has confirmed that the mechanism of CBDA decarboxylation is a direct beta-keto acid pathway. The course of CBDA decarboxylation depends on the time, temperature, and chemical composition of the sample

    Radioecology studies in the vicinity of a closed uranium mine

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    Although the influential area of the former uranium mine at Zirovski vrh, Slovenia has been under continuous radiological monitoring, more detailed radioecology studies, focused on assessing mobility and bioavailability of deposited radionuclides, were initiated about five years ago. The mobility of 238U, 234U, 230Th and 226Ra was studied applying two sequential extraction protocols. The results revealed that both sequential extraction protocols are not comparable as the data obtained are protocol- and radionuclide-dependent. It was found that the most mobile ones were uranium isotopes, followed by 226Ra and 230Th. In addition, uptake of particular radionuclides by the wetland plants (Molinia arundinacea, Juncus effusus and Caltha palustris) grown in soils contaminated with seepage waters from the tailings was studied. The plants contained higher levels of 238U, 226Ra and 230Th compared to the plants from the control site. Activity concentration of 226Ra was the highest for all three plant species. Activity concentration of natural radionuclides in milk collected from the area of Zirovski vrh was comparable to the reference location, except for uranium where the content was higher. The combined annual effective dose for adults consuming milk from the Zirovski vrh area is 13 ± 2 μSv yr−1
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