Thermophysical parameters from laboratory measurements and tests in borehole heat exchangers

Besides the type of thermal regime, the performance of borehole heat exchangers relies on the overall thermal resistance of the borehole. This parameter strongly depends on the underground thermal conductivity, which accounts for most of the heat that can be extracted. The geometric configuration and the increase of thermal conductivity of the grout filling back the bore can yield a non-negligible enhancement in thermal performances. In this paper, we present a study on a pilot geothermal plant consisting of two borehole heat exchangers, 95 m deep and 9 m apart. Laboratory and in situ tests were carried out with the aim of investigating underground thermal properties, mechanisms of heat transfer and thermal characteristics of the filling grouts. Samples of grouting materials were analysed in the lab for assessing the thermal conductivity. An attempt to improve the thermal conductivity was made by doping grouts with alumina. Results showed that alumina large concentrations can increase the thermal conductivity by 25-30%

Digital transformation in healthcare: Analyzing the current state-of-research

Abstract Digital transformation in healthcare is of increasing relevance for both scholars and practitioners in the field. Our article attempts to assess the research question how multiple stakeholders implement digital technologies for management and business purposes. To answer this question, we perform a systematic literature review about the state of the art of digital transformation in healthcare. Our findings show that prior research falls into five clusters: operational efficiency by healthcare providers; patient-centered approaches; organizational factors and managerial implications; workforce practices; and socio-economic aspects. These clusters are linked together into a model showing how these various forms of technology implementation lead to operational efficiencies for services providers. Various directions for future research and management implications are offered

The role of hydrogeological conditions and thermophysical properties on the evaluation of geothermal exchange potential in Central Italy

A multidisciplinary investigation aimed at optimising low enthalpy geothermal plants in the Marche Region (Central Italy) is currently in progress. The main goal is to improve the present-day knowledge of the geological structure, the hydogeological setting and the thermophysical characters of the subsoil and to obtain a better picture of the regional geothermal exchange potential. Since the seasonal climatic variation can affect the temperature and moisture content of the shallower portion of the subsoil, we are focusing our attention on the continuous monitoring of the physical properties of groundwater (temperature and electrical conductivity above all). Moreover, recording of undisturbed temperature-depth profiles in available boreholes is underway. Meanwhile, we have started an extensive campaign of laboratory measurements of thermal conductivity, volume heat capacity, thermal diffusivity, porosity, density and permeability of the several lithologies forming the sedimentary deposits of the Umbria-Marche successions. In this paper, we present the first results so far achieved concerning the field monitoring and the laboratory experiments. These data will be fundamental for the subsequent implementations of numerical thermal models of the subsoil, which incorporate conductive and advective heat transfer and which can evaluate the behaviour of borehole heat exchangers under different hydrogeological conditions

A mathematical model to infer underground thermal characteristics for the design of borehole heat exchangers

Geothermal exchangers are exploited as tools for the indirect analysis of the thermal properties of the underground material. Two simple inverse problems based on different heat transfer models are proposed: the first one is based on the cylindrical model of heat transfer and yields the thermal parameters of the borehole, the second one is based on a forced convective model and yields the soil thermal profile. We test our approach on sets of data collected by direct numerical simulation and from a real experiment

Controls of Radiogenic Heat and Moho Geometry on the Thermal Setting of the Marche Region (Central Italy): An Analytical 3D Geothermal Model

none7sìopenSantini, S.; Basilici, M.; Invernizzi, C.; Jablonska, D.; Mazzoli, S.; Megna, A.; Pierantoni, P.P.Santini, S.; Basilici, M.; Invernizzi, C.; Jablonska, D.; Mazzoli, S.; Megna, A.; Pierantoni, P. P

Iron Metabolism in Liver Cancer Stem Cells

Cancer stem cells (CSC) which have been identified in several tumors, including liver cancer, represent a particular subpopulation of tumor cells characterized by properties similar to those of adult stem cells. Importantly, CSC are resistant to standard therapies, thereby leading to metastatic dissemination and tumor relapse. Given the increasing evidence that iron homeostasis is deregulated in cancer, here we describe the iron homeostasis alterations in cancer cells, particularly in liver CSC. We also discuss two paradoxically opposite iron manipulation-strategies for tumor therapy based either on iron chelation or iron overload-mediated oxidant production leading to ferroptosis. A better understanding of iron metabolism modifications occurring in hepatic tumors and particularly in liver CSC cells may offer new therapeutic options for this cancer, which is characterized by increasing incidence and unfavorable prognosis

Reproducibility and Accuracy of the Radiofrequency Echographic Multi-Spectrometry for Femoral Mineral Density Estimation and Discriminative Power of the Femoral Fragility Score in Patients with Primary and Disuse-Related Osteoporosis

We aimed to investigate the reproducibility and accuracy of Radiofrequency Echographic Multi-Spectrometry (REMS) for femoral BMD estimation and the reproducibility and discriminative power of the REMS-derived femoral fragility score. 175 patients with primary and disuse-related osteoporosis were recruited: one femoral Dual-energy X-ray Absorptiometry (DXA) scan and two femoral REMS scans were acquired. No significant test—retest differences were observed for all REMS-derived variables. The diagnostic concordance between DXA and REMS was 63% (Cohen’s kappa = 0.31) in patients with primary osteoporosis and 13% (Cohen’s kappa: −0.04) in patients with disuse-related osteoporosis. No significant difference was observed between REMS and DXA for either femoral neck BMD (mean difference between REMS and DXA: −0.015 g/cm(2)) or total femur BMD (mean difference: −0.004 g/cm(2)) in patients with primary osteoporosis. Significant differences between the two techniques were observed in patients with disuse-related osteoporosis (femoral neck BMD difference: 0.136 g/cm(2); total femur BMD difference: 0.236 g/cm(2)). Statistically significant differences in the fragility score were obtained between the fractured and non-fractured patients for both populations. In conclusion, REMS showed excellent test-retest reproducibility, but the diagnostic concordance between DXA and REMS was between minimal and poor. Further studies are required to improve the REMS—derived estimation of femoral BMD

Cap rock efficiency of geothermal systems in fold-and-thrust belts:evidence from paleo-thermal and structural analyses in Rosario de La Frontera geothermal area (NW Argentina)

Cap rock characterization of geothermal systems is often neglected despite fracturing may reduce its efficiency and favours fluid migration. We investigated the siliciclastic cap rock of Rosario de La Frontera geothermal system (NW Argentina) in order to assess its quality as a function of fracture patterns and related thermal alteration. Paleothermal investigations (XRD on fine-grained fraction of sediments, organic matter optical analysis and fluid inclusions on veins) and 1D thermal modelling allowed us to distinguish the thermal fingerprint associated to sedimentary burial from that related to fluid migration. The geothermal system is hosted in a Neogene N-S anticline dissected by high angle NNW- and ENE-striking faults. Its cap rock can be grouped into two quality categories: ● rocks acting as good insulators deformed by NNW–SSE and E–W shear fractures, NNE-SSW gypsum- and N-S striking calcite-filled veins formed during the initial stage of anticline growth. Maximum paleo-temperatures (<60°C) were experienced during deposition to folding phases. ● rocks acting as bad insulators deformed by NNW-SSE fault planes and NNW- and WNW-striking sets of fractures associated to late transpressive kinematics. Maximum paleo-temperatures higher than about 115°C are linked to fluid migration from the reservoir to surface (with a reservoir top at maximum depths of 2.5 km) along fault damage zones. This multi-method approach turn out to be particularly useful to trace the main pathways of hot fluids and can be applied in blind geothermal systems where either subsurface data are scarce or surface thermal anomalies are lacking