Search Results (52)

An assembly of fourth-century BCE Samarian silver coins and late-fifth-century BCE Samarian cut silver sheets, Sidonian and Philistian coins from a hacksilber hoard allegedly found in the region of Samaria belonging to the David and Jemima Jeselsohn collection, were characterized by metallurgical analyses. The aims of the research were to identify the items’ composition and manufacturing processes. We affirmed that the Samarian coins were made of silver–copper alloy produced by a controlled process. The microstructural and elemental analyses revealed that the sheets were produced from various materials, including pure silver, silver–copper, and silver–copper–gold alloys, whereas the Sidonian and Philistian coins were made of silver–copper alloy. Continuity in style and production techniques was observed. This information provides a better understanding of the material culture and technological skills in the Persian-period province of Samaria. Full article

The significance of traditional agroforestry systems in preserving and enhancing tropical forest biodiversity in landscapes dominated by human activities has recently been recognized. We assessed the role of traditional vanilla cultivation on sustaining plant diversity in the tropical forests of northern Veracruz, Mexico. We analyzed the composition, alpha (Shannon and Simpson exponential) and beta diversity, the structure (stem density and basal area) and types of regeneration of woody plants across different vanilla production systems, including traditional vanilla plots, the agroforestry production of vanilla, the citrus–vanilla system, and fragments of tropical rain forest. Our findings revealed that traditional vanilla plots preserve 67% of the woody plants’ richness, with an alpha diversity similar to that of the forest fragments. The similarity between vanilla production systems and vegetation fragments was less than 30%. Traditional vanilla plots accounted for 34% of the basal area and had a stem density similar to that of the forest, while retaining 25% of shade-tolerant species. These results suggest that traditional vanilla plots are key landscape elements for conserving plant diversity and supporting the ecological functions of tropical forests. Full article

The paper presents a methodology for determining the minimum split DC link capacitance for a family of three-phase, three-level grid-connected bidirectional AC-DC converters operating under arbitrary power factor under restriction of DC-only zero-sequence injection. The approach is based on the recently revealed generalized behavior of split DC link voltages in the above-mentioned converters family while distinguishing between leading and lagging power factors in order to highlight different impacts on split DC link capacitor voltages pulsating components. The minimum capacitance value is derived from the boundary condition, ensuring the mains voltage remains below or equal to the capacitor voltage at all times. It is revealed that operation with the lowest expected leading power factor should be employed as the design operating point. The accuracy of the proposed methodology is validated by simulations and experiments carried out employing a 10 kVA grid-connected T-type converter prototype. The results demonstrate close agreement between theoretical predictions and experiments, confirming the practical applicability of the proposed method. Full article

Numerous studies have explored the placement of solar panels on the facades or roofs of buildings. This study investigates a new approach to estimating energy generation from transparent, double-sided solar panels integrated into the facade of an existing building, focusing on how the façade’s color influences panel performance. The most significant advantages of integrating double-sided and transparent solar panels on the sides of a building are the natural lighting provided by the sunlight entering the building and the additional energy generated when the radiation returns to the back of the panel. The light beam strikes the front panel, allowing some radiation to pass through the transparent panel to the back side, where it hits the surface. Part of the beam is then reflected toward the rear panel. The fraction of light reflected (albedo) depends on the surface’s color. We first constructed a double-sided, transparent solar panel and integrated it with MATLAB software 2024 code. The model was verified by comparing the simulation results, specifically the I–V and P–V graphs, with data from the manufacturer’s specifications. We conducted an extensive investigation into panels installed on surfaces made of different materials during each installation. This investigation aimed to understand the behavior and performance of the panels when installed on the surfaces of various materials. Full article

Hydrogen is a priority energy vector for energy transition. Its production from renewable feedstock like ethanol is suitable for many applications. The performance of a Ni catalyst supported on samaria-doped ceria in the production of hydrogen by the reforming of ethanol is investigated, adding Sm₂O₃ to CeO₂ in molar ratios of 1:9, 2:8, and 3:7. A CeO₂-supported Ni catalyst was also evaluated for comparative purposes. The supports were prepared by the coprecipitation method and Ni was incorporated by incipient wetness impregnation to obtain catalysts with a Ni/(Ce+Sm) molar ratio of 4/6. The catalysts were characterized by a nitrogen adsorption isotherm, X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Increasing Sm₂O₃ content leads to a more homogeneous distribution of Sm₂O₃ and Ni particles on the support, and higher oxygen mobility, favoring the catalytic properties. The catalyst with a Sm₂O₃/CeO₂ molar ratio of 3/7 showed outstanding behavior, with an average ethanol conversion of 97%, hydrogen yield of 68%, and great stability. The results suggest that the main route for hydrogen production is ethanol dehydrogenation, followed by steam reforming of acetaldehyde, and acetone and ethylene formation are promoted by increasing Sm content in the outer surface of the catalyst. Full article

The promotion of geological heritage can significantly contribute to geoeducation. As geosites are areas that can be visited by everyone and not just experts on the field, a good comprehension of the processes under which they were formed can improve their understanding of the Earth in general. In this work, we have selected two Greek regions, namely Samaria Gorge (Crete) and Mount Pentelicus (Attica), and their sites of geological interest were mapped. Subsequently, some georoutes are proposed, covering both these sites and other locations of cultural, historical, archaeological, and/or religious interest. Through a detailed description of each site and its georoutes, we intend to promote the two areas’ geological heritage on the one hand, and contribute to the development of geoeducation on the other hand. For this purpose, we have also created an online story map and a Virtual Reality (VR) application for each one of them, both addressed to the general public. Full article

The effect of ceria doping of (ZrO₂)_1−x(Sm₂O₃)_x crystals on their phase composition, microhardness and fracture toughness was studied. The (ZrO₂)_0.995−x(Sm₂O₃)_x(CeO₂)_0.005 crystals (where x = 0.032, 0.037 and 0.04) were grown using directional melt crystallization in a cold crucible. The mechanical properties, such as microhardness and fracture toughness, were explored using Vickers indentation. It was shown that the (ZrO₂)_0.995−x(Sm₂O₃)_x(CeO₂)_0.005 solid-solution crystals contained both Ce⁴⁺ and Ce³⁺ ions. Phase analysis data suggested that CeO₂ doping increased the tetragonality degree of the transformable t phase and reduced the tetragonality degree of the non-transformable t’ phase as compared to the (ZrO₂)_1−x(Sm₂O₃)_x crystals. As a result, the t→m phase transition triggered by the indentation-induced stress in the CeO₂-doped crystals was more intense and covered greater regions. CeO₂ doping of the solid solutions increased the fracture toughness of all the crystals studied, whereas the microhardness of the crystals changed only slightly. CeO₂ doping of the (ZrO₂)_1−x(Sm₂O₃)_x solid solutions in the experimental concentration range did not improve the high-temperature phase stability of the crystals and did not prevent high-temperature degradation of their fracture toughness. Full article

This work focuses in-depth on the quantitative relationships between primary first-order microstructural parameters (i.e., volume fractions of various phases and particle size distribution) with the more complex second-order topological features (i.e., connectivity of phases, three-phase boundary length (TPB_L), interfacial areas, or tortuosity). As a suitable model material, a cermet nickel/samaria-doped ceria (Ni-SDC) is used as an anode in a solid oxide fuel cell (SOFC). A microstructure description of nano-sized Ni-SDC cermets, fabricated at various sintering conditions from 1100 °C to 1400 °C, was performed using FIB-SEM nanotomography. The samples were serially sectioned employing a fully automated slicing procedure with active drift correction algorithms and an auto-focusing routine to obtain a series of low-loss BSE images. Advanced image processing algorithms were developed and applied directly to image data volume. The microstructural–topological relationships are crucial for the microstructure optimisation and, thus, the improvement of the corresponding electrode performance. Since all grains of individual phases (Ni, SDC, or pores) did not percolate, special attention was given to the visualisation of the so-called active TPB_L. Based on the determined microstructure characteristics of the prepared Ni-SDC cermets, including simulations of gas flow and pressure drop, thermal treatment at 1200 °C was recognised as the most appropriate sintering temperature. Full article

Recent technological advances have renewed the research interest in current-source inverters (CSIs). Nonetheless, CSI research still falls behind its voltage-source counterpart with regards to topologies, modulation, and control. Acknowledging the above, this paper presents a novel single-phase five-level CSI topology. The proposed circuit utilises eight switches and two inductors for the generation of five distinct output levels while maintaining low output voltage THD and $dv/dt$. Furthermore, by offsetting the inductor currents from a binary 1:2 to a trinary 1:3 ratio, the proposed inverter can generate seven current levels at its output. The inverter offers built-in short-circuit protection and can boost a low input DC voltage to a higher peak AC output voltage. These merits, alongside an electrolytic-capacitor-free design, simple current balancing mechanism, and fault-tolerant characteristics, make it a promising candidate for PV module-integrated inverter (MII) systems. The current topology utilises two inductors but is fully functional with single-inductor operation. The paper provides a functional analysis of the inverter topology alongside the inverter switching states and corresponding conduction paths. A detailed analysis of the inductor current dynamics as well as a current-balancing algorithm for dual- and single-inductor operations are given. The theoretical analysis of the proposed circuit and its functional operation are verified using simulations and experimental results carried out on a laboratory prototype. Full article

Samaria-doped ceria (SDC) overlayers were deposited on Ag cathodes by sputtering. The SDC sputtering time was varied to investigate the properties of the Ag–SDC overlayer cathode-coated fuel cells depending on the thickness of the SDC overlayers. Among the fabricated fuel cells, Ag with a 10-nm-thick SDC overlayer (Ag-SDC10) cathode-coated fuel cell exhibited the highest peak power density of 6.587 mW/cm² at 450 °C, showing higher performance than a pristine Pt-coated fuel cell. Moreover, electrochemical impedance spectroscopy revealed that the Ag-SDC10 cathode-coated fuel cell significantly mitigated polarization loss originating from enhanced oxygen reduction reaction kinetics compared to the pristine Ag-coated fuel cell. Full article

Light-emission data were collected before, during, and after the occurrence of the flash event in pressureless electric-field-assisted (flash) sintering experiments on ZrO₂: 8 mol% Y₂O₃ (8YSZ) and CeO₂: 20 mol% Sm₂O₃ (20SDC) ceramic green pellets to analyze the luminescent emission from the samples. The experiments were performed at 800 °C with an applied electric field of 100 V·cm⁻¹ at 1 kHz, limiting the electric current to 1 A. Luminescence data were obtained in the 200–1200 nm (ultraviolet–visible–near-infrared) range. The deconvolution of the optical spectra allowed for the identification of emission bands in the visible range due exclusively to the samples. The wavelength maxima of the emission bands in 8YSZ were found to be different from those in 20SDC. It is suggested that these bands might originate from the interaction of the electric current, resulting from the application of the electric field, with the depleted species located at the space-charge region at the grain boundaries of these ceramics. The main results represent a contribution to help to clarify the mechanisms responsible for the fast densification with inhibition of grain growth in electroceramics. Full article

This work examines the environmental challenges occasioned by Samaria’s ‘imperial singleness’ in prophet Hosea’s text from an African perspective. The interaction between the ‘seat of power’ in Samaria and imperial forces in Hosea’s time appears to have negatively influenced Israel’s attitude towards land use (Hos 12:1, 2; 1 Ki 21:1–28; 2 Ki 9:26). Such interface becomes evident in a shift, by Samaria’s ‘seat of power’, from Yahweh’s prescribed land-use policy to those of their imperial masters—Assyria and Egypt. Despite Israel’s liberation from Egypt by Yahweh during the exodus (Hos 11:1), their susceptibility to treaty alliances with these imperial forces remains vivid in Hosea’s narrative (Hos 7:1–16; 12:1–2). Echoing the words of Ngwa, such an alliance seemingly classifies Samaria’s monarchy as a ‘localised imperial singularity’ and a ‘single hero’ as against the ‘communal oneness with the divine, humans and the earth itself’. This ‘localised imperial singleness’ and its effect on Israel’s land was subjected to a critical engagement premised on the principles of interconnectedness and the voice of the earth, while a combination of Mburu’s African Hermeneutics and Kavus’ Ecological Hermeneutics is employed for the purpose of critical decolonial discourse. Full article

Asclepias subulata plant extract has previously demonstrated antiproliferative activity and antimutagenicity against heterocyclic aromatic amines (HAAs) commonly found in cooked meat. The objective of this work was to evaluate the in vitro ability of an ethanolic extract from the medicinal plant Asclepias subulata extract (ASE), non-heated and heated (180 °C), to inhibit the activity of CYP1A1 and CYP1A2, which are largely responsible for HAAs bioactivation. Ethoxyresorufin and methoxyresorufin O-dealkylation assays were performed in rat liver microsomes exposed to ASE (0.002–960 µg/mL). ASE exerted an inhibitory effect in a dose-dependent manner. The half inhibitory concentration (IC₅₀) for unheated ASE was 353.6 µg/mL and 75.9 µg/mL for heated ASE in EROD assay. An IC₄₀ value of 288.4 ± 5.8 µg/mL was calculated for non-heated ASE in MROD assay. However, after heat treatment, the IC₅₀ value was 232.1 ± 7.4 µg/mL. Molecular docking of corotoxigenin-3-O-glucopyranoside, one of the main components of ASE, with CYP1A1/2 structure, was performed. Results show that the interaction of corotoxigenin-3-O-glucopyranoside with CYP1A1/2s’ α-helices, which are related with the active site and the heme cofactor, may explain the plant extract’s inhibitory properties. Results showed that ASE inhibits CYP1A enzymatic subfamily and may potentially act as a chemopreventive agent by inhibiting bioactivation of promutagenic dietary HAAs. Full article

Phytolith analysis is a well-established archaeobotanical tool, having provided important insights into pre-Columbian crop cultivation and domestication across Amazonia through the Holocene. Yet, its use as a palaeoecological tool is in its infancy in Amazonia and its effectiveness for reconstructing pre-Columbian land-use beyond archaeological sites (i.e., ‘off-site’) has so far received little critical attention. This paper examines both new and previously published soil phytolith data from SW Amazonia to assess the robustness of this proxy for reconstructing pre-Columbian land-use. We conducted the study via off-site soil pits radiating 7.5 km beyond a geoglyph in Acre state, Brazil, and 50 km beyond a ring-ditch in northern Bolivia, spanning the expected gradients in historical land-use intensity. We found that the spatio-temporal patterns in palm phytolith data across our soil-pit transects support the hypothesis that pre-Columbian peoples enriched their forests with palms over several millennia, although phytoliths are limited in their ability to capture small-scale crop cultivation and deforestation. Despite these drawbacks, we conclude that off-site soil phytolith analysis can provide novel insights into pre-Columbian land use, provided it is effectively integrated with other land-use (e.g., charcoal) and archaeological data. Full article

Statistical characteristics of the wind speed in the Samaria region of Israel have been analyzed by processing 11 years of wind data provided by the Israeli Meteorological Service, recorded at a 10 m height above the ground. The cumulative mean wind speed at a measurement height was shown to be 4.53 m/s with a standard deviation of 2.32 m/s. The prevailing wind direction was shown to be characterized by a cumulative mean azimuth of 226° with a standard deviation of 79.76°. The results were extrapolated to a 70 m height in order to estimate wind characteristics at the hub height of a medium-scale wind turbine. Moreover, Weibull distribution parameters were calculated annually, monthly, and seasonally, demonstrating a good match with histogram-based statistical representations. The shape parameter of the Weibull distribution was shown to reside within a narrow range of 1.93 to 2.15, allowing us to assume a Rayleigh distribution, thus simplifying wind turbine energy yield calculations. The novelty of the current paper is related to gathering wind statistics for a certain area (Samaria), and we are not aware of any published statistics regarding wind velocity and direction in this area. These data may be interesting for potential regional wind energy development in which the obtained Weibull distribution could be used in calculations for the expected power generation of particular turbines with a known power dependence on velocity. We have given an example of these calculations for three different types of turbines and obtained their yield in terms of electric power and economic value. We also point out that the fact that realistic wind velocity statistics can be described well by an analytic formula (Weibull distribution) is not trivial, and in fact, the fit may have been poor. Full article