Search Results (584)

Wild potato relatives are vital for breeding programs to tackle rising temperatures. This study proposes a methodological approach based on the examination of genetic variation among 19 accessions belonging to Solanum chacoense and Solanum commersonii from the Embrapa Potato Genebank under heat stress (HS). Heat tolerance coefficient (HTC) was calculated using genotypic values predicted through mixed models. After 15 days of heat stress (DHS), a significant variation in gas exchange and chlorophyll fluorescence indicates strong breeding potential and photosystem resilience. By 35 DHS, increased pigment variation suggests acclimation. Based on predicted genotypic values, S. chacoense outperforms S. commersonii in tuber production and gas exchange under HS, and principal component analysis (PCA) performed using the HTC shows early resistance driven by photosynthesis, mid-term by tuber yield, and long-term by gas exchange and tuber production. Genotypes BRA00167017-3, BRA00167023-1, BRA00167025-6, and BRA00167028-0 excel in heat comprehensive evaluation values (HCEVs)/comprehensive principal component value (F) rankings, demonstrating robust photosynthesis, thermoregulation, and tuber yield. Cluster analysis identifies these as highly tolerant, ideal for breeding heat-resilient potatoes. These PCA-derived weights and genotype clustering system provide a precise tool for selecting heat-tolerant wild potato germplasm, categorizing them into highly tolerant, moderately tolerant, sensitive with late recovery, and highly sensitive groups acquired for specific objectives of the breeding programs to climate change. Full article

Norway spruce (Picea abies (L.) Karst.) is experiencing large-scale decline across Central Europe, with climate warming and bark beetle (Ips typographus L.) outbreaks as primary drivers. In lowland Białowieża Forest, Poland, spruce occupies a range of habitats that differ in their suitability for long-term persistence. We hypothesized that climate change accelerates spruce decline by reducing resilience in suboptimal habitats and increasing susceptibility to bark beetle outbreaks, with long-term persistence limited to optimal hydrological sites. To address this, we analysed spruce share from 1902–2018, its distribution across suitable versus unsuitable habitats, and long-term climate records in relation to outbreaks. Historical maps, forest site classifications, and meteorological data were used to calculate hydro-climatic indices (HTC, SPEI-12, Selyaninov), and outbreak relationships were tested using Welch’s t-test and point-biserial correlation, including lag effects. Spruce share increased from 12% in 1902 to 27% in 2015 and then declined to 9% by 2018. In 2015, 75% of spruce-dominated stands occurred in unsuitable habitats. Bark beetle outbreaks were significantly associated with drought, with outbreak years showing lower precipitation (–121 mm), reduced Selyaninov k (mean 1.40 vs. 1.61), and more negative SPEI-12 values (–0.48 vs. 0.07) compared to non-outbreak years (p < 0.05). One-year lag analysis indicated drought as both a predisposing and triggering factor. These findings highlight the interaction of habitat suitability and drought as a key driver of spruce decline, supporting adaptive management strategies that retain spruce in optimal habitats while converting suboptimal stands to more drought-tolerant species. Full article

Background and Objectives: Hematological parameters are increasingly being investigated as readily accessible biomarkers for the diagnosis of obstructive sleep apnea syndrome (OSAS). In our study, we aimed to investigate the relationship between OSAS and albumin indices and the uric acid-to-HDL ratio (UHR). Methods: The demographic and laboratory data and AHI (apnea–hypopnea index) values of 613 patients who underwent polysomnography were obtained retrospectively from their files. Blood parameters such as white blood cells (WBCs), red blood cell distribution width (RDW), red blood cells (RBCs), hemoglobin (Hb), hematocrit (Hct), platelets (PLTs), C-reactive protein (CRP), albumin, blood urea nitrogen (BUN), and high-density lipoproteins (HDLs) were obtained from the files. Laboratory indices such as the BUN-to-albumin ratio (BAR), neutrophil-to-albumin ratio (NAR), RDW-to-albumin ratio (RAR), CRP-to-albumin ratio (CAR), and UHR were calculated. OSAS was categorized as simple snoring (SS) (control) (AHI < 5), mild (5 ≤ AHI < 15), moderate (15 ≤ AHI < 30), and severe (AHI ≥ 30). The patients were also grouped as severe (AHI ≥ 30) and non-severe (5 > AHI < 30) OSAS and compared in terms of laboratory parameters and indices. Results: Of the 613 participants, 366 (59.7%) were men, and the average age of participants was 55.22 ± 11.13 years. The biomarkers such as RBCs, Hb, Htc, CRP, BUN, creatinine, uric acid, HDLs, CAR, RAR, BAR, and UHR showed significant differences between OSAS patients and controls. WBCs, basophils, RBCs, RDW, Htc, PLTs, HDLs, uric acid, RAR, NAR, and UHR indices were significantly different between the severe OSAS and non-severe OSAS groups (p < 0.05). BAR (OR = 1.151; CI = 1.056 − 1.256; p = 0.001) and UHR (OR = 2.257; 95% CI = 1.507 − 3.382; p < 0.001) were the most important indices predicting OSAS, while RAR (OR = 1.844; CI = 1.224 − 2.778; p = 0.003) and UHR (OR = 2.203; 95% CI = 1.496 − 3.243; p < 0.001) were the strongest indices associated with severe OSAS. Conclusion: In our study, RAR, BAR, and UHR indices were closely associated with the presence and severity of OSAS. These indices can be considered low-cost, readily available methods for predicting OSAS patients. Full article

In steel continuous casting, the secondary cooling zone is usually equipped with air-mist nozzles. Spray nozzle clogging is a common problem that reduces cooling efficiency and affects product quality. This study uses a 3D CFD model to investigate its impact on heat transfer. The model includes the full-size caster geometry and actual nozzle layout to analyze the effect of clogging on the cooling process. The solidification process is modeled using the enthalpy-porosity method. Spray cooling is defined through empirical HTC correlations on the slab surface. The study focuses on how nozzle clogging changes the surface temperature, cooling rate, and metallurgical length (ML). Simulation results show that clogging raises the local surface temperature by about 100 K and increases the ML. More clogged nozzles lead to a longer ML. Clogging near the meniscus has a stronger impact, showing that early-stage cooling plays an important role in solidification. Even a single clogged nozzle can increase the ML by 3.2%, highlighting the significant effect of nozzle clogging on the casting process. Full article

This study experimentally investigates the boiling heat transfer characteristics of R32 and R410A refrigerants in heat exchangers, systematically analyzing the effects of tube thickness, saturation temperature, latent heat, liquid-phase density, and viscosity. The average boiling heat transfer coefficients (HTCs) of R32 and R410A were compared across varying mass flow rates and saturation temperatures. The results reveal that, independent of tube thickness, the boiling HTC of R32 exhibits a non-monotonic increase followed by a decrease with rising mass flow rate. Additionally, elevated saturation temperatures reduced vaporization latent heat, liquid-phase density, and gas-phase viscosity, while the flow pattern may also change. Meanwhile, R32 demonstrated superior boiling heat transfer performance compared to R410A under equivalent conditions. Furthermore, the correlation is proposed to predict the HTCs, indicating ±10% prediction error. This study provides critical insights for optimizing refrigeration systems and advancing heat exchanger modeling frameworks. Full article

Water contamination by heavy metals, particularly lead, derived from industrialization, climate change, and urbanization, represents a critical risk to human health and the environment. Several agricultural biomass residues have demonstrated efficacy as contaminant adsorbents. In this context, the study aimed to evaluate the potential of sugarcane tip (ST) waste biomass treated by hydrothermal carbonization (HTC) to produce hydrochar as an adsorbent material for Pb²⁺ in aqueous solutions. Samples were synthesized from the waste biomass at temperatures of 180 °C, 215 °C, and 250 °C, with a constant pressure of 6 MPa. Aqueous solutions of Pb²⁺ were prepared at concentrations of 10, 25, 50, 75, and 100 mg/L. Each solution was stirred at 1 g of hydrochar at 150 rpm, 25 °C, and pH 5 for 15 to 120 min. The solutions were filtered and stored at 4 °C for flame atomic absorption spectrophotometry analysis. In all cases, equilibrium was reached rapidly—within 15 min or less—as indicated by the stabilization of q_t values over time. At an initial concentration of 100 mg L⁻¹, the highest equilibrium uptake was observed for the hydrochar synthesized at ST HTC 180 °C (4.90 mg g⁻¹), followed by 4.58 mg g⁻¹ and 4.52 mg g⁻¹ for ST HTC 215 °C and ST HTC 250 °C, respectively. For the ST HTC 180 °C, the Sips model provided the best correlation with the experimental data, exhibiting a high maximum capacity (q_max = 240.8 mg g⁻¹; K_s = 0.007; n = 1.09; R² = 0.975), which reinforces the heterogeneous nature of the material’s surface. Hydrothermal synthesis increased the amount of acidic active sites in the ST HTC 180 °C material from 1.3950 to 3.8543 meq g⁻¹, which may influence the electrical charge of the Pb²⁺ adsorption process. HTC-treated sugarcane tip biomass represents a promising alternative for the synthesis of adsorbent materials, contributing to water remediation and promoting the circular economy by sustainably utilizing agricultural waste. Full article

The potential of Virtual Reality (VR) in enhancing learning and training is being widely explored. The relationship of immersion, as one of the core technical features of VR, with knowledge types has not been fully explored. This study aims to investigate how VR immersion levels (high vs. low) affect the acquisition of declarative and procedural knowledge, as well as related cognitive and affective factors. A 2 × 2 mixed design was adopted, with 64 college students who had no VR experience and no background in professional medical knowledge being randomly assigned to either a high-immersion group (using HTC Vive Pro headsets) or a low-immersion group (using desktop monitors). Participants completed learning tasks on thyroid and related diseases (declarative knowledge) and cardiopulmonary resuscitation (procedural knowledge), followed by knowledge tests and self-report questionnaires to measure presence, motivation, self-efficacy, cognitive load, and emotional states. Results showed that high immersion significantly improved learning outcomes for both types of knowledge with large effect sizes. In both knowledge domains, high immersion also enhanced presence, intrinsic motivation, self-efficacy, and positive emotions. However, cognitive load was reduced only for declarative knowledge, and no significant effects were observed for self-regulation. These findings highlight the differential impact of VR immersion on knowledge acquisition and provide insights for optimizing VR-based educational interventions. Full article

Microplastics (MPs) represent a persistent class of emerging contaminants, of which significant amounts can be found in sewage sludge. In this study, the effect of hydrothermal carbonization (HTC) temperature on MPs and the properties of digested sewage sludge (DSS) was evaluated. The HTC process was carried out at temperatures of 200, 210, and 220 °C for 2 h in a batch reactor, and the solid products were subjected to (i) mass balance and fuel properties and (ii) microplastic occurrence analysis using Confocal Raman Microspectroscopy and Scanning Electron Microscopy. In digested sludge, 2700 ± 475 MP particles/100 g d.m. were detected, mostly fragments with ~350 ± 100 fibers. Hydrocharcontained only black and brown fragments in the following amounts: 4175 ± 575 (200 °C), 4450 ± 700 (210 °C), and 1450 ± 590 (220 °C), respectively, after 2 h. The microplastic removal rate was 54% for the highest temperature. Polystyrene (PS) was identified in untreated sludge, while only PE was detected after HTC at 200–210 °C, and no MPs were identifiable at 220 °C. The surfaces of post-MPs exhibited progressive degradation with increasing HTC temperature. The results confirm that HTC lowers the content and alters the physicochemical properties of microplastics, reducing their thermal stability and degrading their structure, while simultaneously improving the fuel properties of hydrochars by increasing the calorific value and carbon content. Full article

Due to its complex composition and toxicity, the waste liquid from hydrothermal carbonization (HTC) poses a serious environmental challenge that must be addressed before disposal. In this study, the photochemical treatment of HTC liquid in a microreactor flow system was investigated. The effects of wavelength, the presence of atmospheric oxygen, oxidizing agent (H₂O₂) and catalyst (FeSO₄), residence time and pH on the efficiency of the photo-treatment were investigated. In addition, the influence of the addition of deep eutectic solvent (DES) on photo-treatment was studied. The results showed that the photochemical treatment was more efficient at 365 nm than at 420 nm, and that the acidic conditions gave better results than the basic ones. UV₃₆₅ treatment in the presence of H₂O₂ (at a dosage of 1 vol%) resulted in removal efficiencies of 31.6% for COD, 17.6% for TOC, 16.9% for NH₄-N and 17.2% for PO₄-P. The addition of FeSO₄ caused coagulation/flocculation effects, but improved phosphorus removal. The addition of DES resulted in slight discolouration of the liquid and proved unsuccessful in COD removal. The GC-MS analysis and 3D-EEM spectra showed significant changes in the fate of organics and in the fluorescence intensity of aromatic proteins and humic acid-like substances. Photochemical treatment in a microreactor flow system in the presence of H₂O₂ under the selected operating conditions reduced the content of organics and nutrients in the HTC liquid, but the process liquids still showed toxic effects on the organisms V. fischeri and Daphnia magna. Full article

Healthy nutrition is of great importance to maintain the physical and mental health of individuals. In recent years, products such as snack bars have become widely used to encourage healthy eating habits. This study compared the environmental footprints of four snack bar prototypes that adhere to the Mediterranean diet (MD) through a life cycle assessment (LCA). LCA is used to calculate an environmental footprint, encompassing six impact categories: Global Warming Potential (GWP), Abiotic Depletion (AD), Human Toxicity (Cancer (HTC) and Non-Cancer Effects (HTNC)), land use (LU), and water use (WU). The total impacts were as follows (prototypes 1–4, respectively): GWP 0.221/0.224/0.234/0.194 kg CO₂-eq; AD 2.35/2.87/2.63/2.01 MJ; HTC 9.13 × 10⁻¹⁰/7.69 × 10⁻¹⁰/9.82 × 10⁻¹⁰/9.88 × 10⁻¹⁰ CTUh; HTNC 1.03 × 10⁻⁸/1.51 × 10⁻⁹/4.16 × 10⁻⁹/3.03 × 10⁻⁹ CTUh; LU 14.8/21.6/21.8/10.8; WU 0.132/0.287/0.198/0.068 m³. Prototype 4, which yielded the lowest value across four indicators (GWP, AD, LU, and WU), is the most environmentally favorable. A range of 89–91% of the GWP originates from raw material production, while the share attributed to transportation is 3–4%. Nuts and dried fruit contents are decisive for WU and LU. The findings suggest that environmental impacts are highly sensitive to ingredient composition and agricultural inputs, and that selecting raw materials and optimizing the supply chain is critical for mitigation. Full article

Improving the pool boiling heat transfer by changing the properties of the heating surface has been experimentally studied by many researchers. In this paper, two novel microstructured surfaces with open channels were simulated and investigated. The two microstructured surfaces had different cavity positions and different groove widths of open channels. At the same time, a pool boiling experiment on the plain-heated surface was carried out to verify the reliability and accuracy of the CFD model. The results showed the relationship between the heat flux and wall superheat. Moreover, the bubble dynamic behaviors of different surfaces were obtained. It was found that both microstructured surfaces could enhance the pool boiling heat transfer coefficient (HTC) and critical heat flux (CHF). Enlarging the length of the groove gap can not only increase the heat transfer area, but also increase the bubble nucleation rate. However, constantly increasing the groove width will cause the horizontal coalescence of bubbles on the heating surface at low heat flux. When the negative effect of bubble coalescence is higher than the enhancement effect, the boiling heat transfer capacity of the heating surface will decrease unless the heat flux is high enough to delay bubble coalescence. Full article

In Korea, policy efforts are being made to achieve carbon neutrality in the agricultural sector by promoting the production and utilization of livestock manure-derived biochar. Recently, new quality standards for livestock manure biochar have been introduced. However, some of the produced biochar does not meet the criteria required for soil carbon sequestration. In this study, a literature review evaluated the technical feasibility of livestock manure biochar to support its industrial utilization and activation. This study performed a literature review to comparatively assess the physicochemical properties of woody, herbaceous, and livestock manure biomass, and to evaluate the quality standards of biochar derived from these feedstocks through pyrolysis and hydrothermal carbonization (HTC). According to an analysis of previous studies, the carbon content of woody biochar produced by pyrolysis ranged from 46.3% to 93.5% (n = 29), with average H/C and O/C molar ratios of 0.49 and 0.09, respectively. Herbaceous biochar exhibited a carbon content ranging from 26.1% to 83.8% (n = 34), with mean H/C and O/C molar ratios of 0.48 and 0.28, respectively. Thus, most woody and herbaceous biochars met the biochar quality criteria (H/C < 0.7, O/C < 0.4). In contrast, manure-derived biochar demonstrated a comparatively lower carbon content, ranging from 29.0% to 44.6% (n = 21). The average H/C molar ratio for manure-derived biochar was higher at 0.60, and 73% of samples exceeded the established quality threshold for H/C (<0.7). Hydrothermal carbonization (HTC), which is suitable for high-moisture feedstocks such as manure, yields hydrochar with an average H/C ratio of 1.01, indicating lower aromaticity and reduced carbon stability, thereby limiting its potential for long-term carbon sequestration. These findings underscore the necessity for region-specific standards and further investigation into the properties of manure-derived biochar to promote sustainable soil carbon sequestration practices. Full article

In order to investigate the formation pathway of hydrochar during hydrothermal carbonization (HTC) and to identify the optimal process conditions for producing high-quality pyrolysis feedstock, the effect of hydrothermal temperature (220, 250, and 280 °C) on tar and hydrochar properties were analyzed by GC-MS, XRD, XPS, FT-IR, and SEM using protein-rich brewer’s spent grain (BSG) as raw material. The results showed that aromatic compounds play a major role in tar production. Increasing hydrothermal temperature significantly enhanced volatile matter removal and consequently increased the fixed carbon content from 23.14 wt.% in HC-220 to 27.07 wt.% in HC-280, while the catalytic effect of H₃O⁺ produced by high-temperature water facilitated the dehydration and decarboxylation reactions, resulting in a reduction in the H/C atomic ratio from 1.44 in HC-220 to 1.25 in HC-280 and the O/C atom ratio from 0.32 in HC-220 to 0.25 in HC-280. HC-280 exhibited superior fuel properties, with a high heating value (HHV) of 35.4 MJ/kg. XPS analysis indicated that elevated temperatures promote the conversion of sp³ C to sp² C (the value of sp² C/sp³ C increased from 1.13 in HC-220 to 1.49 in HC-280), significantly increasing the aromatic condensation degree of hydrochar. The more pronounced reduction in the -OH content compared to -COOH indicated that dehydration reactions predominated over decarboxylation. Finally, the formation pathways of hydrochar during HTC were revealed based on the properties of different products. The results demonstrate that HTC is an effective method for converting BSG into pyrolysis feedstock with potential applications in energy production. Future work should focus on the technical–economic assessment of the process at a pilot scale and evaluating the hydrochar’s performance in real pyrolysis systems. Full article

In this study, Stevia rebaudiana biomass was hydrothermally carbonized (HTC) at 215 °C for 60 min with acrylic acid (AA) as a catalyst at concentrations of 0.25, 0.50, and 1.00 mol L⁻¹. The maximum hydrochar yield (48.5%) was obtained at 0.25 mol L⁻¹ AA, while fixed carbon contents ranged from 20.79% to 34.27%. Higher heating values (HHV) varied between 26.95 and 36.61 MJ kg⁻¹, with the highest catalytic HHV (32.20 MJ kg⁻¹) achieved at 1.00 mol L⁻¹ AA (HC15). Acrylic acid addition significantly promoted deoxygenation, reducing the O/C ratio from 0.67 in raw biomass to 0.21, thereby improving fuel quality. FT-IR and XRD analyses indicated enhanced aromatization and partial graphitization with increasing acid concentration, while SEM images revealed carbon microspheres and porous morphologies. Thermogravimetric analysis showed that HC15 exhibited the lowest mass loss and highest residual carbon, indicating superior thermal stability. GC-MS analysis demonstrated that acrylic acid markedly increased phenolic derivatives, with phenol content rising from 19.47% (without catalyst) to 40.92% (1.00 mol L⁻¹ AA). The aqueous phase contained TOC values of 14,280–28,728 mg/L and COD values of 43,227–113,920 mg/L. Overall, acrylic acid-assisted HTC enhances both the energy-related properties of hydrochars and the chemical diversity of liquid products, providing a sustainable route for valorizing Stevia rebaudiana waste into value-added fuels and chemicals. Full article

Municipal sewage sludge (S.S.) and abundant olive-tree pruning on Lesvos Island present both a disposal challenge and an untapped energy resource. This study proposes and evaluates on a preliminary level an integrated system that utilizes both sewage sludge and pruning. The integrated system converts sewage sludge into Hydrochar (HC) via Hydrothermal Carbonization (HTC), removes the aqueous phase using passive solar distillation, and co-gasifies the dried HC with olive pruning in an autothermal downdraft gasifier. HTC experiments on anaerobically digested sludge produced HC with higher heating values exceeding 20 MJ kg⁻¹ while reducing the chemical oxygen demand of the process liquor. Gasification modelling, using the MAGSY equilibrium model, demonstrated that replacing up to 50% of lignocellulosic biomass with HC increased hydrogen content and the Lower Heating Value (LHV) of syngas. Mass and energy balances suggest that the system could provide approximately 590 kW of continuous power, contributing around 4720 MWh to the island’s annual electricity generation. These results indicate that combining HTC, solar distillation, and co-gasification offers a viable pathway to close waste loops, reduce landfill needs, and deliver renewable energy. Future work will focus on Aspen Plus design and optimization, along with a life-cycle assessment in order to assess the environmental benefits. Full article