John S. Lioumbas

The Gadouras Reservoir, Rhodes Island’s primary water source, experiences recurrent whiting events—milky turbidity from calcium carbonate precipitation—that challenge treatment operations, with impacts compounded by a major 2023 wildfire in this fire-prone Mediterranean setting. To elucidate these dynamics, a pragmatic, multi-source monitoring framework integrates archived Sentinel-2 and Landsat imagery with treatment-plant records (2017–mid-2025). Unitless spectral indices (e.g., AreaBGR) for whiting detection and chlorophyll-a proxies are combined with laboratory measurements of turbidity, pH, total organic carbon, manganese, and hydrological metrics, analyzed via spatiotemporal Hovmöller diagrams, Pearson correlations, and interrupted time-series models. Two seasonal whiting regimes are identified: a biogenic summer mode (southern origin; elevated chlorophyll-a; water temperature > 15 °C; pH > 8.5) and a non-biogenic winter mode (northern inflows). Following the wildfire, the system exhibits characteristics that could be related to possible hypolimnetic anoxia, prolonged whiting, a ~50% rise in organic carbon, and a manganese excursion to ~0.4 mg L⁻¹ at the deeper intake. Crucially, the post-fire period shows a decoupling of AreaBGR from turbidity (r ≈ 0.233 versus ≈ 0.859 pre-fire)—a key diagnostic finding that confirms a fundamental shift in the composition and optical properties of suspended particulates. The manganese spike is best explained by the confluence of a wildfire-induced biogeochemical predisposition (anoxia and Mn mobilization) and a consequential operational decision (relocation to a deeper, Mn-rich intake). This framework establishes diagnostic baselines and thresholds for managing fire-impacted reservoirs, supports the use of remote sensing in data-scarce systems, and informs adaptive operations under increasing climate pressures.

This study aims to optimize the frying process of natural porous materials (like potatoes) by enhancing heat and mass transfer phenomena through significant horizontal acceleration values following a spatially periodic pattern that alternates the intensity of inertia forces uniformly across the frying vessel. The generated horizontal inertial forces act complementary to the normal vertical buoyancy force for the creation of agitating convective currents in the oil and for vapor bubbles’ departure from the surface of frying objects. The use of an innovative frying device, employing simultaneous rotation around two vertical axes at a different speed in a so-called planetary type of motion, serves to facilitate this production of horizontal acceleration values that allows intensifying the performance of frying. The present investigation examines the impact of rotational speed, along with oil temperature and frying duration, on the water loss and sensory evaluation of fried items. The potato-to-oil ratios typically found in industrial frying operations are employed. The intended outcome is a more energy-efficient frying process, reduced cooking times, and a healthier product due to lower frying temperatures and the consequent decreased formation of harmful compounds. This approach carries substantial implications for food processing, potentially enhancing productivity while limiting operational costs.

Water utilities often use extended open surface water reservoirs to produce drinking water. Biotic and abiotic factors influence the water level, leading to alterations in the concentration of the dissolved substances (in cases of flood or drought), entry of new pollutants (in case of flooding) or reduction in the availability and inflow speed of water to the treatment plant (in case of drought). Spaceborne image analysis is considered a significant surrogate for establishing a dense network of sensors to monitor changes. In this study, renowned inundation mapping techniques are examined for their adaptability to the inland water reservoirs’ conditions. The results, from the Polyphytos open surface water reservoir in northern Greece, showcase the transferability of the workflows with overall accuracies exceeding—in cases—98%. Hydroperiod maps generated for the area of interest, along with variations in the water surface extent over a four-year period, provide valuable insights into the reservoir’s hydrological patterns. Comparison among different inundation mapping techniques for the surface water extent and water level reveal challenges and limitations, which are related to the spatial resolution, the data take frequency and the influence of the landscape synthesis beyond the water reservoir boundaries.

The purpose of this work was to study the transition from the smooth to the wavy stratified flow regime for various pipe inclination angles and liquid physical properties. The accurate characterization of both the structure of the gas-liquid interface and the flow field inside the liquid layer can improve our physical understanding of the mechanisms involved in the evolution of waves in stratified gas-liquid flow. To study the influence of liquid properties on the mechanisms promoting wave formation, several liquids are used (i.e., water, Tween®, and aqueous-glycerin solutions). The experiments are conducted in a 24 mm i.d. pipe for various inclination angles (1–9°) with respect to the horizontal position. Liquid layer thickness time records are acquired using a parallel-wire conductance technique from which mean layer thickness, rms, and power spectra of the fluctuations as well as wave celerities are calculated. Measurements of the axial velocity component in the liquid layer using laser-Doppler anemometry are also reported. Statistical analysis of such local liquid velocity data in conjunction with the liquid layer characteristics reveals a strong interplay between wave evolution at the interface and the flow field development inside the liquid layer. Finally, results of numerical calculations using a CFD code are obtained to facilitate data interpretation.