Search Results (102)

This work—mixing an original experimental approach, as well as numerical simulations—proposes to study film boiling modes around a small nickel sphere. While dealing with a simple looking phenomenon that is found in many industrial processes and has been solved for basic quenching regimes, we focus on describing precisely how vapor formation and film thicknesses, as well as vapor bubble evacuation, affect cooling kinetics. As instrumenting small spheres may lead to experimental inaccuracies, we optically captured, using a high-speed camera, the vapor film thickness at mid height, the vapor bubble volume, and the bubble detachment frequency, along with the heat flux. More precisely, an estimation of the instant sphere temperature, in different conditions, was obtained through cooling time measurement before the end of the film boiling mode, subsequently facilitating heat flux evaluation. We encountered a nearly linear decrease in both the vapor film thickness and vapor bubble volume as the sphere temperature decreased. Notably, the detachment frequency remained constant across the whole temperature range. The estimation of the heat fluxes confirmed the prevalence of conduction as the primary heat transfer mode; a major portion of the energy was spent increasing the liquid temperature. The results were then compared to finite element simulations using an in-house multiphysics solver, including thermic phase changes (liquid to vapor) and their hydrodynamics, and we also captured the interfaces. While presenting a challenge due to the contrast in densities and viscosities between phases, the importance of the small circulations along them, which improve the heat removal in the liquid phase, was highlighted; we also assessed the suitability of the model and the numerical code for the simulation of such quenching cases when subcooling in the vicinity of a saturation temperature. Full article

Recently, a new solarization method gained a great deal of attention thanks to various advantages in comparison with both the traditional one and soil fumigation (alternative soil treatment based on the use of chemical agents). This method implements traditional solarization by spraying a biodegradable black liquid over the soil surface before the application of a thermic film. This creates a thin black film that acts like a “black body”, significantly increasing soil temperatures at various depths. Thanks to higher temperatures, it is possible to eliminate most of the pathogens in shorter times compared to traditional solarization. In the present paper, the results of different trials carried out on green beans, Romanesco broccoli, and lettuce were reported. The aims of this work were to demonstrate the efficacy on soil borne pathogens, its lower impact on living soil fungal biodiversity and the agronomical performance of the new solarization method. All crops tested showed a significant yield increase when grown in soil treated with the innovative solarization method. Romanesco broccoli also exhibited improved inflorescence quality. Solarization had a positive impact on overall crop productivity: green beans showed a maximum yield increase of 165.3%, lettuce yields rose by 47.5%, and Romanesco broccoli yields were 111.5% higher compared to the non-solarized control. These results confirm that the new solarization method is more effective, as well as environmentally, economically, and socially sustainable compared to traditional methods. Full article

The use of rhenium-based catalysts (Re₂C, Re₃B, ReB₂, and ReS₂) obtained by mechanosynthesis in the pyrolysis of cellulose and lignin from 500 to 800 °C using 10 and 20 wt.% of catalysts is reported. The mechanosynthesis of ReS₂ has been reported for the first time. The catalytic pyrolysis of cellulose resulted in maximum H₂ production at 800 °C and 10 wt.% catalyst, with 44% H₂ yield using a Re₃B catalyst. In contrast, lignin catalytic pyrolysis also showed maximum production under the same conditions, with an 86.1% H₂ yield using the NiO/SiO₂ catalyst; however, the catalyst did not drastically enhance H₂ production. H₂ formation by cellulose pyrolysis is a thermocatalytic process, whereas lignin pyrolysis is an entirely thermic process. A reaction mechanism was proposed to explain the H₂ formation by both catalytic cellulose and lignin pyrolysis. Full article

A three-dimensional numerical investigation using ethylene–oxygen was conducted to examine the characteristics of detonation waves in a non-premixed rotating detonation engine (RDE) across three equivalence ratio conditions: fuel-lean, stoichiometric, and fuel-rich. The study aims to identify the distinct timescales associated with detonation wave propagation within the combustor and to analyze their impact on detonation wave behavior, emphasizing the influence of equivalence ratio and injector behavior on detonation wave characteristics. The results indicate that the wave behavior varies with mixture concentration, with the ethylene injector demonstrating greater stiffness compared to the oxygen injector. In lean mixtures, characterized by excess oxidizer, waves exhibit less intensity and slower progression toward equilibrium, resulting in prolonged reaction times. Rich mixtures, with excess fuel, also show a delayed approach to equilibrium and an extended chemical reaction timescale. In contrast, the near-stoichiometric mixture achieves efficient combustion with the highest thermicity, rapidly reaching equilibrium and exhibiting the shortest chemical reaction timescale. Overall, the induction timescale is generally 2–3 times longer than its respective chemical reaction timescale, while the equilibrium timescale spans a broad range, reflecting the complex, rapid dynamics inherent in these chemical processes. This study identifies the role of the characteristic chemical timescale in influencing the progression of pre-detonation deflagration in practical RDEs. Prolonged induction times in non-ideal conditions, such as those arising from equivalence ratio variations, promote incomplete reactions, thereby contributing to pre-detonation phenomena and advancing our understanding of the underlying flow physics. Full article

Obesity has emerged as a global epidemic, creating an increased burden of weight-related diseases and straining healthcare systems worldwide. While the fundamental principle of energy balance—caloric intake versus expenditure—remains central to weight regulation, real-world outcomes often deviate from simplistic predictions due to a multitude of physiological and environmental factors. Genetic predispositions, variations in basal metabolic rates, adaptive thermogenesis, physical activity, and nutrient losses via fecal and urinary excretion contribute to interindividual differences in energy homeostasis. Additionally, factors such as meal timing, macronutrient composition, gut microbiota dynamics, and diet-induced thermogenesis (DIT) further modulate energy utilization and metabolic efficiency. This Perspective explores key physiological determinants of the energy balance, while also highlighting the clinical significance of thrifty versus spendthrifty metabolic phenotypes. Key strategies for individualized weight management include precision calorimetry, circadian-aligned meal timing, the use of protein- and whole food diets to enhance DIT, and increases in non-exercise activity, as well as mild cold exposure and the use of thermogenic agents (e.g., capsaicin-like compounds) to stimulate brown adipose tissue activity. A comprehensive, personalized approach to obesity management that moves beyond restrictive caloric models is essential to achieving sustainable weight control and improving long-term metabolic health. Integrating these multifactorial insights into clinical practice will enhance obesity treatment strategies, fostering more effective and enduring interventions. Full article

Dynamic relaxations play an important role in understanding the nature of glass. The conventional methods to explore dynamic relaxations rely on the measurement of mechanical and thermic properties, while new methods that may provide a new perspective to probe dynamic relaxation are desperately required. Here, we show that the β-relaxation of metallic glasses (MGs) can be unveiled by electrical resistivity (ER). Irreversible β-relaxation leads to an increment in electrical resistivity, which can be fitted by the Kohlrausch–Williams–Watts equation well. In contrast, the ER results of the initialized sample only exhibit a negligible change during annealing, which indicates that the reversible β-relaxation change cannot be manifested by ER testing. This work provides the ER measurement as a new means to explore the dynamic relaxation of MGs, which may offer a new insight into the understanding of β-relaxation in glass materials. Full article

A critical meta-analysis of the past decade’s investigations was carried out with the aim of assessing the use of plant-based techniques for soil remediation. Potentially toxic element (PTE) contaminated soils were selected since these contaminants are considered hazardous and have long-term effects. Furthermore, energy, aromatic, and medicinal plants were studied as their high-value products seem to be affected by PTEs’ existence. Lead (Pb), Cu, Cd, Zn, Cr, Co, Ni, Hg, and As accumulation in different parts of plant species has been investigated using proper indices. Aromatic plants seem to provide high phytoremediation yields. Increasing toxicity levels and the coexistence of many metals enhance the accumulation capacity of aromatic plants, even of toxic Cd. In plants usable as energy sources, antagonistic effects were observed, as the simultaneous presence of Cu and Cd resulted in lower thermic capacity. Finally, in most of the plants studied, it was observed that the phytostabilization technique, i.e., the accumulation of metals mainly in the roots of the plants, was often used, allowing for the aboveground part to be almost completely free of metallic pollutants. Using plants for remediation was proven to be advantageous within a circular economy model. Such a process is a promising solution, both economically and environmentally, since it provides a useful tool for keeping environmental balance and producing safe goods. Full article

Echinoderms are among the most charismatic megabenthic taxa in mesophotic and deep waters. However, they generally have a scattered distribution and are difficult to collect, especially on hardgrounds, so defining their abundance, distribution and ecological preferences is challenging. The largest available Italian remotely operated vehicle dataset, including 624 dives carried out between 2006 and 2022 in coastal and offshore areas in the depth range of 40–1825 m, was used to assess echinoderm diversity and large-scale geographic and bathymetric distributions. Thirty-nine taxa were identified, including three rarely reported from the Mediterranean basin. The maximum diversity and occurrence of the deep-sea echinoderm fauna were reported from the northern areas, and generally, they decreased with depth and distance from the coast. Species, mostly of Atlantic origin, were mainly distributed according to their thermic preferences. The recorded species occurred in a large variety of habitats, including some in which, differently from what was reported in the literature, they formed dense aggregations. The high densities of individuals were hypothesised to be related, in some cases, to reproductive, feeding or stress situations. Environmental predictors were considered in order to both investigate patterns in community composition and the response of the studied community to them. This work enhances the knowledge of deep-sea Mediterranean echinoderms, fundamental to implementing more effective monitoring and conservation strategies for the habitats in which they thrive. Full article

Birds select habitats to optimize resources and maximize fitness, with some species recently colonizing new areas, like the Eurasian Collared Dove (ECD) in the Iberian Peninsula. The ECD spread across Europe in the early 20th century from South Asia. This study reanalyzes data from the Atlas of Breeding Birds in the Province of Alicante (SE Spain) to identify macrohabitat-level environmental variables related to its occurrence and abundance in this semi-arid Mediterranean landscape during the breeding season. We performed Hierarchical Partitioning analyses to identify important environmental variables for the species associated with natural vegetation, farming, topography, hydrographical web, urbanization, and climate. Results show that ECD has a higher occurrence probability near anthropic areas (isolated buildings, suburban areas), water points (medium-sized ponds), larger crop surfaces (total cultivated area), and warmer localities (thermicity index). The species avoids natural habitats like pine forests and scrublands. Abundance is positively linked to anthropic features like larger suburban areas and urban-related land uses. These findings can help predict its expansion in regions with a Mediterranean climate in South America, North America, or Australia, and its continuous natural expansion and population increase within the Mediterranean basin and Europe. Full article

The aim of this paper is to investigate the influence of the molecules of conducting polymers on the properties of potentiometric sensors. Two conducting polymers, poly(3-octylthiophene-2,5-diyl) and poly(3,4-ethylene-1,4-dioxythiophene), were compared in the context of the design of ion-selective electrodes. This study offers a comparison of the most popular conducting polymers in the context of the design of potentiometric sensors. Firstly, the properties of both materials, such as their microstructure, electrical performance, wettability, and thermic properties, were examined. Subsequently, conducting polymers were applied as transducer layers in potassium-selective sensors. The properties of both groups of sensors were evaluated using the potentiometry method. Research has shown that the presence of poly(3-octylthiophene-2,5-diyl) (POT) in the transducer layer makes it superhydrophobic, leading to a long lifetime of sensors. On the other hand, the addition of poly(3,4-ethylene-1,4-dioxythiophene) polystyrene sulfonate (PEDOT:PSS) allows for the enhancement of electrical capacitance parameter values, which beneficially influence the stability of the potentiometric response of sensors. Both examined conducting polymers turned out to be perfect materials for transducer layers in potentiometric sensors, each being responsible for enhancing different properties of electrodes. Full article

Background: Total energy expenditure (TEE) is the total energy expended by an individual to sustain life, activities, and growth. TEE is formed by four components: resting energy expenditure (REE), activity energy expenditure (AEE), growth-related energy expenditure (GEE), and the thermic effect of feeding (TEF). Some energy expenditure (EE) components may change throughout childhood and cannot be reliably estimated using prediction formulae. Objective: To summarize measured TEE components as reported in the literature in healthy and critically ill children. Methods: We searched MEDLINE, EMBASE, and CINAHL for studies published between 1946 and 7 September 2023. The primary outcome was energy expenditure. Included studies were published in English and measured one or more of TEE, AEE, GEE, and TEF with Indirect Calorimetry or Doubly Labeled Water in participants between 1 month and 18 years of age. We excluded studies reporting only REE or using predictive equations. Following abstraction, reported values were converted into kcal/kg/day or kcal/day as possible. Weighted mean values were calculated using median or means of EE measurements. Results: We found 138 studies, 8163 patients, and 16,636 eligible measurements. The median (IQR) study sample size was 20 (12, 35) patients. TEE was the most evaluated component. The median (IQR) TEE in infants was 73.1 (67.0, 76.5), in children 78.0 (66.0, 81.3), and in adolescents was 44.2 (41.8, 51.9) kcal/kg/day. Very few studies reported on GEE and TEF. Conclusions: This is one of the first studies that summarizes components of total energy expenditure in different pediatric age groups in healthy and critically ill children. Growth- and feeding-associated energy expenditure are poorly reported in healthy children, while all components of TEE (except REE) are poorly reported in critically ill children. Full article

(1) Objective: The aim of this study was to assess the biological behavior of bone tissue on a machined surface (MS) and modifications made by a laser beam (LS) and by a laser beam incorporated with hydroxyapatite (HA) using a biomimetic method without thermic treatment (LHS). (2) Methods: Scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM/EDX) was performed before and after installation in the rabbit tibiae. A total of 20 Albinus rabbits randomly received 30 implants of 3.75 × 10 mm in the right and left tibias, with two implants on each surface in each tibia. In the animals belonging to the 4-week euthanasia period group, intramuscular application of the fluorochromes calcein and alizarin was performed. In implants placed mesially in the tibiofemoral joint, biomechanical analysis was performed by means of a removal torque (N/cm). The tibias with the implants located distally to the joint were submitted for analysis by confocal laser microscopy (mineral apposition rate) and for histometric analysis by bone contact implant (%BIC) and newly formed bone area (%NBA). (3) Results: The SEM showed differences between the surfaces. The biomechanical analysis revealed significant differences in removal torque values between the MSs and LHSs over a 2-week period. Over a 4-week period, both the LSs and LHSs demonstrated removal torque values statistically higher than the MSs. BIC of the LHS implants were statistically superior to MS at the 2-week period and LHS and LS surfaces were statistically superior to MS at the 4-week period. Statistical analysis of the NBA of the implants showed difference between the LHS and MS in the period of 2 weeks. (4) Conclusions: The modifications of the LSs and LHSs provided important physicochemical modifications that favored the deposition of bone tissue on the surface of the implants. Full article

Chronic tympanic membrane perforation represents a prevalent otological condition, necessitating a reliable animal model for the validation and safety assessment of surgical techniques and materials employed in myringoplasty. This prospective study involved the establishment of chronic tympanic membrane perforation animal models in 16 chinchillas. A thermic myringotomy was conducted on the right ear (study group), followed by cold instrument myringotomy, coupled with the topical application of mitomycin C and dexamethasone solution on the left ear (control group). Results revealed that tympanic membrane perforations in the study group persisted for a minimum of 4 weeks in 93.7% of cases and extended to 12 weeks in 62.5% of the cases. In contrast, all tympanic membrane perforations in the control group were present at 4 weeks, with only 37.5% persisting after 12 weeks, although statistical tests did not find significant differences between the two groups (chi-square: p-value = 0.157, Kruskal–Wallis: p-value = 0.093, Mann–Whitney: p-value = 0.121). The thermic myringotomy employed to induce chronic tympanic membrane perforation in animals demonstrated efficiency and sustainability. This model, characterized by stability and reproducibility, holds promise for future experimental applications in the field. Full article

Background: Acute compartment syndrome is a major surgical emergency with complex pathophysiology and a highly unpredictable pattern of evolution. We hypothesized that the onset of acute compartment syndrome of the leg or forearm is associated with variations in the surface temperature of the distal segment (foot or hand) with a distinct pattern, which acts as an early warning sign. Materials and Methods: We developed a monitoring device that consists of two thermic sensors attached to a modular limb splint, which continuously measure the temperature difference between the proximal and distal regions of the limb (i.e., arm–hand, thigh–foot). Firstly, we investigated both the arm–hand and thigh–foot temperature gradients of hospitalized patients’ healthy limbs (43 patients, 56 upper limbs, 64 lower limbs) in order to establish a baseline. Secondly, we examined the correlation between the thermic gradients and intracompartmental pressure values in compartment syndrome limbs (20 patients, 6 upper limbs, 14 lower limbs). Results: For the control group, the mean values for the normal limb thermic gradients were −0.17 °C for the upper limbs. and 0.03 °C for the lower limbs. In the impending compartment syndrome group (defined by intracompartmental pressure values), the mean index was −0.38 °C. In the fully developed compartment syndrome group, the mean value was 4.11 °C. Discussions: Analysis was performed using the ANOVA one-way statistical method. This showed significant differences between the compartment syndrome group and the impending and control groups. A decreasing trend in the thermic gradient in patients with impending compartment syndrome compared with the control group was noted. Conclusions: The thermic gradient of limbs presenting signs of impending compartment syndrome decreases as a result of the increased temperature of the distal segment. This pattern can be used as an early diagnostic method for acute compartment syndrome. This technique is non-invasive and bears no risk to the patient, allowing facile continuous monitoring during immobilization. Full article

(1) Background: Periprosthetic joint infections (PJIs) are severe and frightening complications in orthopaedic surgery, and they are generally divided into three categories: early infections (those occurring within the first 4–6 weeks), delayed infections (those occurring between 3 and 24 months), and late infections (those occurring more than 2 years after surgery). PJI treatment comprises “debridement, antibiotics, and implant retention” (DAIR), single-stage revision, and double-stage revision. Nowadays, to improve the chances of retaining an infected implant and to improve the traditional DAIR method, a modified surgical technique has been developed, named DAPRI (debridement, antibiotic pearls, and retention of the implant). Our study aims to present an up-to-date concept evaluation of the DAPRI technique and its success rate. (2) Methods: Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) standards were followed, applying a protocol defined by the authors: a total of 765 articles were identified, and at the end of the screening process only 7 studies were included. (3) Results: Currently, the DAPRI procedure can be performed only on patients who have had PJI symptoms for less than 4 weeks, and in order to achieve the highest success rate, indications are quite strict: it is appropriate in patients with acute, superficial infections without sinus tract presence, and well-fixed implants with known sensitive bacteria. The DAPRI surgical method follows a step-by-step process consisting of a first phase of biofilm identification with intra-articular injection of methylene blue, followed by biofilm removal (thermic, mechanical, and chemical aggression), and a last step consisting of prevention of PJI recurrence by using calcium sulphate antibiotic-added beads. (4) Conclusions: The DAPRI approach improves the traditional DAIR technique. It is a correct treatment for acute and early haematogenous PJI, and improves the DAIR success rate. Full article