Educational trails of the Racławka Valley Nature Reserve and their potential for geoeducation

The Racławka Valley is located west of Krakow, in the Krakow-Częstochowa Upland. This is a place of high bio- and geodiversity, where various rocks of different ages outcrop in vast excavation pits, narrow gorges or form characteristic monadnocks. The richness of various morphological forms and special habitats led to the constitution of a nature reserve, covering most of the Racławka Valley and adjacent, southern parts of the Szklarka Valley. Three educational trails lead through the reserve, connecting a number of geosites. The Geotourism Students’ Scientific Club (GSSC) from AGH University of Science and Technology examined the usability of these trails for geoeducation. After completing geotourism valorisation, adequate teaching materials were prepared, and different age groups were guided around the trails. Their comprehension has been verified by quizzes and opinions gathered through questionnaires. On the bases of these, the three educational trails were widely described and assessed in respect for their terrain difficulty, accessibility, and infrastructure. Each trail has a leitmotif and a specific theme, however geosites from different trails can be combined together to get a route of a chosen theme. The GSSC also released three new geotourism guidebooks, one for each trail, as a result of AGH rector's grant projects in the years 2018–2020.Dolina Racławki położona jest na zachód od Krakowa, na Wyżynie Krakowsko-Częstochowskiej. Stanowi ona obszar o dużejbio- i georóżnorodności, gdzie rozmaite skały o różnym wieku odsłaniają się w rozległych wyrobiskach, na ścianach wąwozów lub w postaci ostańców. Ze względu na bogactwo form morfologicznych i wykształcone na nich siedliska, większość doliny Racławkii przyległą, południową część doliny Szklarki objęto rezerwatem przyrody. Przez obszar rezerwatu prowadzą trzy ścieżki dydaktyczne łączące szereg geostanowisk. Koło Naukowe Geoturystyka (KNGt) z Akademii Górniczo-Hutniczej zbadało ich przydatność dla geoedukacji. Po dokonaniu waloryzacji geoturystycznej opracowano materiały dydaktyczne, a następnie po ścieżkach oprowadzono różne grupy wiekowe. Za pomocą quizów sprawdzono zrozumienie przez uczestników omawianych tematów, a opinie zebrano w formie ankiet. Działania te umożliwiły dokładne opisanie ścieżek oraz ich ocenę pod kątem trudności terenu, dostępnościi infrastruktury. Każda ze ścieżek ma motyw przewodni, można je jednak z powodzeniem łączyć, by zaplanować trasę o określonej tematyce. KNGt przygotowało też trzy przewodniki geoturystyczne po dolinie Racławki, po jednym dla każdej ze ścieżek, w ramach Grantu Rektora AGH w latach 2018–2020

Critical evaluation of the thermometric performance of ratiometric luminescence thermometers based on Ba3(VO4)2:Mn5+,Nd3+ for deep-tissue thermal imaging

Near-infrared (NIR) luminescence thermometry has been brought to the fore as a reliable approach for remote thermal sensing and imaging. Lanthanide (Ln3+)-based nanophosphors are often proposed as NIR nanothermometers of choice. However, the combination of Ln3+ with transition metal (TM) ions has recently emerged as a strategy to introduce additional emission bands and/or TM ↔ Ln3+ energy transfer pathways whose temperature dependence can be harnessed to increase the sensitivity of the thermometric approach. Yet, the examples of the combination of luminescence nanothermometers working in the NIR and hosting simultaneously TM and Ln3+ are scarce, leaving plenty of space for the exploration of these systems. Herein, we report on the preparation and optimization of the thermometric performance of Ba3(VO4)2:Mn5+,Nd3+ nanophosphors. The different temperature dependences of the emission intensity of the two doped luminescent centers allow using the ratio between Mn5+ and Nd3+ as a reliable thermometric parameter with a relative thermal sensitivity of 1% K−1 close to room temperature. We then showcase the suitability of this nanophosphor for employment in 2D NIR luminescence thermal imaging. Lastly, we critically evaluate the possibility of using this thermal imaging approach through opaque media with the help of phantoms with tissue-like optical properties. As expected, a loss of reliability of the thermometric method is observed due to tissue-induced photon scattering and absorption that differentially affect the emission of Mn5+ and Nd3+. Overall, the reported results underscore the good performance of the newly developed nanothermometer, while consolidating the call for the use of luminescence nanothermometers working in the time-domain (rather than in the spectral domain) for deep-tissue thermal readout/imaging

On site-selective optically and thermally induced processes in Lu2O3:Tb,Ta\mathrm{{Lu_2O_3}:Tb,Ta} storage phosphors

Photo- thermo- and optically stimulated luminescence properties of $\mathrm{Lu_2O_3:Tb,Ta}$ ceramics sintered at 1700 °C in air were investigated. Low temperature (10 K) excitation and emission spectra using synchrotron excitation in the range of 150–330 nm are also discussed. The effect of the dopant contents on the various luminescence effects and processes was tackled. The ceramics showed intense thermoluminescence (TL) and the glow curve consisted of two main peaks around 170 and 250 °C upon 5 °C/s heating rate. The shape of the glow curve and TL intensity depended strongly on the dopant concentrations. Above 0.1% of their contents the TL quickly lessened to disappear around 1%. This was in contrary to photoluminescence which hardly showed any quenching up to the concentration of 1%. In addition to the regular first order TL kinetics some contribution from tunneling and semi-localized transitions was proved

Tracing mechanism of optically and thermally stimulated luminescence in Lu2O3:Tb,MLu_2O_3:Tb,M (M = Hf, Zr, Ti) ceramic storage phosphors

A series of energy storage phosphors, Lu2O3:Tb,M (M = Hf, Zr, Ti), were investigated by means of photo- and thermoluminescence techniques to compare the effect of the co-dopant from the same group of periodic table of elements on charge carriers trapping capability and trap parameters. Most of the investigated processes were tracked individually for the Tb3+ in the two different metal sites offered by the Lu2O3 host – noncentrosymmetric C2 and centrosymmetric C3i. It is proved that both Tb3+ ions participate in hole trapping and electrons are immobilized in traps whose depths are defined by the co-dopant. Deepest traps, ∼1.79 eV, appear upon Ti addition, while Zr and Hf generate traps of very similar, ∼1.40–1.44 eV, depths. The stored energy may be released not only by means of thermal stimulation but also upon the impact of optical photons. Light from the 390–430 nm range of wavelengths was found the most efficient in the latter process. Also deep red radiation of 780 nm releases most of the trapped electrons in Zr/Hf co-doped ceramics but is much less effective in the case of Tb, Ti material. Consistent scheme of electronic levels engaged in charge carriers trapping and subsequent generation of thermo- and optically stimulated luminescence was constructed

Lu2O3-based storage phosphors. An (in)harmonious family

Ceramics of Lu2O3 activated with either Tb3+ or Pr3+ and co-doped with one of the transition metal ions – Ti, Hf or Nb – were investigated for their energy storage properties. Photoluminescence, thermoluminescence (TL) and optically stimulated luminescence spectra were recorded and discussed together with thermoluminescent glow curves. The Pr3+ and Tb3+ ions constitute luminescent centers and participate in the energy storage. However, as the thermoluminescence glow curves showed, the Ti, Hf and Nb co-dopants have a significant impact on glow curve pattern, in particular on the temperature at which the maximum thermoluminescence occurred. For the Tb,Ti and Pr,Ti as well as for the Pr,Nb one main TL peak appeared around 360–370 °C. For other compositions it varied from 210 °C for Tb,Nb, through 230 °C for Tb,Hf to 250 °C for Pr,Hf. In either case additional TL components of lower intensities were observed. They spread over 50–450 °C. The TL data led to the conclusion that the co-dopant – a necessary component to induce a significant energy storage capacity in the materials – may not be directly involved in trapping the excited carriers. Instead, it may rather generate other point defects which, individually or as clusters, would do the work. Energy storage was found to be connected with an appearance of an induced excitation/absorption band spreading over around 350–500 nm and peaking near 400 nm. A prolonged stimulation into this band caused green (for Tb-series) or red (for Pr-series) optically stimulated emission. Such a stimulation allows entirely bleaching out the induced absorption. The optically stimulated luminescence for all members of the Tb-series led to luminescence from both C2 and C3i sites offered by the host lattice. All compositions of the Pr-series produced optically stimulated emissions upon 400 nm radiation only by means of the Pr3+ occupying the C2 site.Accepted Author ManuscriptRST/Fundamental Aspects of Materials and Energ

Ścieżki edukacyjne Rezerwatu Przyrody Dolina Racławki i ich potencjał geoedukacyjny

The Racławka Valley is located west of Krakow, in the Krakow-Częstochowa Upland. This is a place of high bio- and geodiver-sity, where various rocks of different ages outcrop in vast excavation pits, narrow gorges or form characteristic monadnocks. The richness of various morphological forms and special habitats led to the constitution of a nature reserve, covering most of the Racławka Valley and adjacent, southern parts of the Szklarka Valley. Three educational trails lead through the reserve, connecting a number of geosites. The Geotourism Students’ Scientific Club (GSSC) from AGH University of Science and Technology examined the usability of these trails for geoeducation. After completing geotourism valorisation, adequate teaching materials were prepared, and different age groups were guided around the trails. Their comprehension has been verified by quizzes and opinions gathered through questionnaires. On the bases of these, the three educational trails were widely described and assessed in respect for their terrain difficulty, accessibility, and infrastructure. Each trail has a leitmotif and a specific theme, however geosites from different trails can be combined together to get a route of a chosen theme. The GSSC also released three new geotourism guidebooks, one for each trail, as a result of AGH rector's grant projects in the years 2018–2020.Dolina Racławki położona jest na zachód od Krakowa, na Wyżynie Krakowsko-Częstochowskiej. Stanowi ona obszar o dużej bio- i georóżnorodności, gdzie rozmaite skały o różnym wieku odsłaniają się w rozległych wyrobiskach, na ścianach wąwozów lub w po-staci ostańców. Ze względu na bogactwo form morfologicznych i wykształcone na nich siedliska, większość doliny Racławki i przyległą, południową część doliny Szklarki objęto rezerwatem przyrody. Przez obszar rezerwatu prowadzą trzy ścieżki dydaktyczne łączące szereg geostanowisk. Koło Naukowe Geoturystyka (KNGt) z Akademii Górniczo-Hutniczej zbadało ich przydatność dla geoedukacji. Po dokona-niu waloryzacji geoturystycznej opracowano materiały dydaktyczne, a następnie po ścieżkach oprowadzono różne grupy wiekowe. Za po-mocą quizów sprawdzono zrozumienie przez uczestników omawianych tematów, a opinie zebrano w formie ankiet. Działania te umożliwiły dokładne opisanie ścieżek oraz ich ocenę pod kątem trudności terenu, dostępności i infrastruktury. Każda ze ścieżek ma motyw przewodni, można je jednak z powodzeniem łączyć, by zaplanować trasę o określonej tematyce. KNGt przygotowało też trzy przewodniki geoturystycz-ne po dolinie Racławki, po jednym dla każdej ze ścieżek, w ramach Grantu Rektora AGH w latach 2018–2020

Characterization of Al₂O₃ Matrix Composites Fabricated via the Slip Casting Method Using NiAl-Al₂O₃ Composite Powder

This work aimed to characterize Al2O3 matrix composites fabricated by the slip casting method using NiAl-Al2O3 composite powder as the initial powder. The composite powder, consisting of NiAl + 30 wt.% Al2O3, was obtained by mechanical alloying of Al2O3, Al, and Ni powders. The composite powder was added to the Al2O3 powder to prepare the final powder for the slip casting method. The stained composite samples presented high density. EDX and XRD analyses showed that the sintering process of the samples in an air atmosphere caused the formation of the NiAl2O4 spinel phase. Finally, the phase composition of the composites changed from the initial phases of Al2O3 and NiAl to Al2O3, Ni, and NiAl2O4. However, in the area of Ni, fine Al2O3 particles remaining from the initial composite powder were visible. It can be concluded that after slip casting, after starting with Al2O3 and the composite powder (NiAl-Al2O3) and upon sintering in air, ceramic matrix composites with Ni and NiAl2O4 phases, complex structures, high-quality sintered samples, and favorable mechanical properties were obtained