Thermal Conditions Research Articles

Contribution of Glazed Balconies as a Passive Heating System in Contemporary Buildings in Northern Portugal

To mitigate greenhouse gas emissions responsible for global warming and climate change, governments have undertaken concerted efforts and established goals to restructure production and consumption patterns within the current global economy. The construction sector, which in Europe has significant energy use and related greenhouse gas emissions, recognizes adopting passive heating and cooling systems for buildings as a viable solution. The revival of vernacular passive solar strategies emerges as opportune within this context. Through dynamic simulations, this study aims to analyze and quantify the potential contribution of glazed balconies, a traditional passive heating system, to improve contemporary constructions’ thermal behavior and comfort conditions in mild temperate climates, such as in northern Portugal. Results indicate that this system can significantly enhance a building’s energy efficiency, reducing energy needs for heating and cooling by up to 47% while extending periods of thermal comfort indoors by nearly 900 h per year compared to buildings with non-glazed balconies. Proper use of natural ventilation and shading devices is essential to ensure optimal system performance and prevent overheating. This research underscores the potential of glazed balconies as a sustainable solution for enhancing contemporary buildings’ thermal-energy performance and comfort, contributing to the transition towards carbon-neutral constructions.

Investigating the spatial propagation patterns of meteorological drought events and underlying mechanisms using complex network theory: A case study of the Yangtze River Basin, China

AbstractThe spatial propagation patterns of meteorological drought events (MDEs) and underlying mechanisms contribute to elucidating and forecasting drought evolution. In this study, gridded MDEs in the Yangtze River Basin (YRB) throughout the entire year, wet season and dry season were extracted from 3-month Standardized Precipitation Evapotranspiration Index (SPEI-3) series. Event synchronization (ES) and complex networks (CN) were employed to construct the MDE synchronization networks and MDE spatial propagation networks for various periods. The former were utilized to identify MDE synchronized subregions where MDEs co-occur and co-evolve in the YRB, while the latter were used to quantify the MDE spatial propagation patterns over both the basin and its subregions. The driving mechanisms behind MDE spatial propagation were further investigated by diagnosing the concomitant drought-inducing climate systems. The findings reveal the presence of four MDE synchronized subregions during the wet season and five subregions during the entire year and dry season. These subregions exhibited distinct spatial propagation patterns of MDEs, aligning with overall findings across the YRB. Notable differences were observed between wet and dry seasons, with various subregions exhibiting distinctive spatial propagation patterns during each season. These patterns are driven by variations in the controlling atmospheric circulation systems, leading to anomalies of wind patterns and moisture distribution, ultimately resulting in deficient moisture supply. The variations of tropical sea surface thermal conditions, influences of the Tibetan Plateau and MDE self-propagation triggered by land–atmosphere feedback are considered as three primary influencing factors for MDE spatial propagation in the YRB.

Talc: A natural mineral base catalyst for the one pot synthesis of bis(pyrazolyl)methane derivatives under thermal and solvent-free conditions

In this work, we were decontaminated the ore to extract the talc, directly. Then, we used talc as a heterogeneous basic catalyst for one pot synthesis of bis(pyrazolyl)methane derivatives via the condensation of ethylacetoacetate, hydrazine hydrate and aromatic aldehyde derivatives under thermal and solvent-free conditions. This solid type of catalyst was identified by fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDS), EDS mapping and Brunauer–Emmett–Teller (BET) theory. Heterogeneous and solvent-free conditions, catalyst recyclability, high yields of the products and short reaction times are some advantages of this method. The reusability of the catalyst was examined for five times and it was successfully used in each run without any significant decreasing in its activity.

Simulation and verification of cylinder head’s temperature field for marine low-speed engine

Abstract The high load capacity of marine low-speed engines poses a challenge to the thermal load of the cylinder head and temperature field simulation can guide its structural design and optimization. The 3-dimensional models of the fluid domain for the cooling water and the solid domain for the cylinder head are established and meshed, the fluid domain model is simulated to research the heat transfer pattern by Fluent software, and the surface temperature and heat transfer coefficient of the cooling water is calculated. The thermal boundary conditions of the gas in the cylinder are simulated through the analysis of the engine working process. The temperature of the cylinder head is calculated based on the fluid-structure interaction model with the thermal boundary conditions by Workbench software. The validation of the model is carried out by comparing the simulated and measured temperature data in the heated inner wall of the cylinder head. The research results show that compared with the measured value, the error of simulation results is small, which shows that the model and method are reasonable. The temperature in the inner wall of the combustion chamber is low, which can provide possibilities to appropriately improve the power density of the low-speed engine and reduce the risk of low-temperature corrosion.

Synergy and site dependent kinetics of photo-thermal catalysis over Pt/TiO2 for methanol decomposition

Photo-thermal catalysis which interplay the heat and light-induced effects have drawn broad attention owing to their synergistic effect to extend the capability of chemical transformation. Here, the effect of heat and/or light on methanol decomposition has been clarified. On Pt/TiO2, light irradiation activates the TiO2 and enhance the absorption and the oxidation of intermediates. The main intermediate under PTC condition is formaldehyde, which is the same to TC condition rather than methyl formate under PC condition. Differences CO absorption site correlates with the key intermediates under PC and TC/PTC conditions. Light and heat display their strengths in a synergistic manner, optimizing the activity to promote efficient catalytic processes which is verified to be photo-assisted thermal catalysis. This work offers detailed mechanistic understanding of the surface species and paves the way for an educated microkinetic modeling approach under photo and/or thermal condition over oxide-supported metal catalysts.

Quantitative correlation between temperature difference and sintering neck length in material extrusion-based additive manufacturing

The performance of polymeric parts fabricated via material extrusion-based additive manufacturing (MEAM) is significantly influenced by the sintering neck length between filaments. Despite its importance, elucidating the underlying mechanism governing the formation of inter-filament sintering necks is challenging due to the difficulties in monitoring temperature fields during MEAM. In this work, the thermal condition in MEAM was simplified using a printer with a tubular hotbed, coupled with a high temporal-spatial resolution infrared (IR) camera to monitor temperature field variations during printing. An advanced IR image processing method, integrating multi-directional retrieval and whole-loop average filtering, was developed to accurately measure temperature differences between filaments. By correlating these measurements with micro-CT characterizations, a quantitative relationship between temperature difference and sintering neck length was established. Through single- or multi-loop defect experiments, microscopic defect detection and analysis were conducted, achieving the prediction of sintering neck length variations at a 10 μm level with an 85 % accuracy. This work is believed to provide potential value for further accurate prediction of the mechanical properties of MEAM parts.

The effect of indoor temperature on work performance of fifty-eight people in a simulated office environment

There is general agreement that indoor thermal conditions affect Office Work Performance (OWP); however, consensus on the specific characteristics of this relationship, such as its shape, effect size, and prediction accuracy, remains elusive. To address this gap, we conducted a study with fifty-eight participants exposed to temperatures (23°C, 25°C, 27°C, and 29°C) in a simulated tropical office environment over 165 min to determine how temperature affects OWP. These temperatures were chosen to mirror typical conditions in tropical buildings. We maintained constant variables, including relative humidity (50%), clothing (0.5 clo), metabolic rate (1.1 MET), and airspeed (0.1ms-1). We measured OWP using one cognitive ability and seven neuropsychological tests targeting executive functions like flexible thinking, working memory, and self-control. OWP remained constant across all tested temperatures, despite some participants reporting thermal discomfort at the higher temperatures. Our findings support the Maximum Adaptability Model —aka extended-U model— which claims that human performance remains relatively stable over a wide range of thermal conditions typically found indoors. Given the consistent performance within the typical temperature range for tropical office buildings and participants’ preferred and accepted 25°C the most, we caution against lowering air conditioning set points below this level as it may lead to unnecessary cooling. We shared the database and code, to ensure our research data is openly available and our methodology can be used in other climates to reproduce our results.

Coupled indoor air quality and dynamic thermal modelling to assess the potential impacts of standalone HEPA filter units in classrooms

The quality of the classroom environment, including ventilation, air quality and thermal conditions, has an important impact on children’s health and academic achievements. The use of portable HEPA filter air cleaners is widely suggested as a strategy to mitigate exposure to particulate matter and airborne viruses. However, there is a need to quantify the relative benefits of such devices including the impacts on energy use. We present a simple coupled dynamic thermal and air quality model and apply it to naturally ventilated classrooms, representative of modern and Victorian era construction. We consider the addition of HEPA filters with, and without, reduced opening of windows, and explore concentrations of carbon dioxide (CO2), PM2.5, airborne viral RNA, classroom temperature and energy use. Results indicate the addition of HEPA filters was predicted to reduce PM2.5 by 40–60% and viral RNA by 30–50% depending on the classroom design and window opening behaviour. The energy cost of running HEPA filters is likely to be only 1%–2% of the classroom heating costs. In scenarios when HEPA filters were on and window opening was reduced (to account for the additional clean air delivery rate of the filters), the heating cost was predicted to be reduced by as much as − 13%, and these maximum reductions grew to − 46% in wintertime simulations. In these scenarios the HEPA filters result in a notable reduction in PM2.5 and viral RNA, but the CO2 concentration is significantly higher. The model provides a mechanism for exploring the relative impact of ventilation and air cleaning strategies on both exposures and energy costs, enabling an understanding of where trade-offs lie.

Thermal dynamics in deep shale reservoirs: Influences of the kerogen microstructural behavior on the gas adsorption/desorption capacity

In shale gas extraction projects, an investigation into the mechanisms of energy/mass transfer associated with shale gas adsorption/desorption in organic matter (kerogen) microstructure under high temperature and stress condition is crucial for improving the efficiency of shale gas production. This study presents a coupling thermo-hydro-mechanical model based on an improved fractal method that could explain the microstructural evolution of the kerogen system and the resultant alterations during the gas adsorption/desorption process under varying thermal conduction, gas seepage, and stress conditions. The influence of porosity, diameter, and tortuosity on the abundance, length, and complexity of kerogen networks under coupled multi-field effects is evaluated. The significance of this study is it could address the following aspects quantitively: (1) the spatiotemporal evolution of kerogen fractal dimensions following various extraction timelines; (2) the influence of shale temperatures on kerogen structures; (3) the influence of the kerogen fractal dimension on the shale gas desorption capacity and production efficiency; and (4) under different temperatures, when the fractal dimension/tortuosity fractal dimension of kerogen changes due to extraction disturbances, the volumetric deformation induced by gas adsorption increases by a maximum of 26.1%/decreases by 28.1% and in the later stages of extraction, the maximum gas pressure decreases by 44.7%/increases by 47.1%. The proposed fractal method adeptly reveals shale gas desorption behaviors under multi-field coupling conditions from a microscopic perspective, which cannot be found in the literature.

Effects of thermal treatment on air-dried density, color change, average surface roughness, and sound absorption capacity of Scots pine

This study was conducted to investigate some characteristics of thermally treated Scots pine (Pinus sylvestris L.) wood specimens such as air-dried density, color change, average surface roughness, and sound absorption capacity. Heat treatment of Scots pine wood was performed at atmospheric pressure at 140, 160, 180, and 200 °C for 2 h. As a result, the air-dried density values of the thermally treated wood decreased as the temperature of the thermal treatment increased. With the increase of thermal treatment temperature, an increase in total color change values was detected on the surfaces of the samples and the color of the samples became darker. The average surface roughness (Ra) value of samples improved due to thermal treatment conditions and the highest value was determined in thermally treated samples at 200 °C as 3.59 μm. At 140 °C the value of maximum sound absorption coefficient was observed to be 0.48 at 2500 Hz and the highest sound transmission loss value, which was 36.7 dB, was measured at 6300 Hz and at 200 °C.

Changes in the ability of Listeria monocytogenes to resist thermal treatment and simulated gastric condition after exposure to sequential stresses in minced meat

In this study, Listeria monocytogenes from minced pork was evaluated for changes in resistance to thermal treatment and gastric fluid following environmental stresses during food processing. Bacteria were exposed to cold stress, followed by successive exposures to different stressors (lactic acid (LA), NaCl, or Nisin), followed by thermal treatments, and finally, their gastrointestinal tolerance was determined. Adaptation to NaCl stress reduced the tolerance of L. monocytogenes to subsequent LA and Nisin stress. Adaptation to LA stress increased bacterial survival in NaCl and Nisin-stressed environments. Bacteria adapted to Nisin stress showed no change in tolerance to subsequent stress conditions. In addition, treatment with NaCl and LA enhanced the thermal tolerance of L. monocytogenes, but treatment with Nisin decreased the thermal tolerance of the bacteria. Almost all of the sequential stresses reduced the effect of a single stress on bacterial thermal tolerance. The addition of LA and Nisin as a second step of stress reduced the tolerance of L. monocytogenes to gastric fluid, whereas the addition of NaCl enhanced its tolerance. The results of this study are expected to inform processing conditions and sequences for meat preservation and processing and reduce uncertainty in risk assessment of foodborne pathogens due to stress adaptation.

Thermal boundary conditions and rotation effects on the onset of casson fluid convection in a permeable layer produced by purely interior heating

In this work, we inspect the effect of thermal boundary conditions and rotation on the coming of Casson fluid convective motion generated by purely internal warming in a flat porous layer. Two types of thermal boundaries are utilized, namely, type (I) both boundary planes are isothermal and type (II) bottom boundary plane is insulated and top plane is isothermal. The altered Darcy model is used to characterize the rheological performance of Casson fluid movement in porous medium. The classical Horton–Rogers Lapwood stability examination is accomplished and the resultant eigenvalue problem is resolved numerically with the help of advanced-term Galerkin technique with the internal Rayleigh Darcy number as the eigenvalue. It is observed that the Taylor Darcy number has a stabilizing weight while the Casson parameter shows the dual influence on the system. The structure is more stable when both boundary planes are isothermal. The magnitude of the convection cells falls with increasing both the Taylor Darcy number and the Casson parameter. In the absence of Taylor Darcy number, the system’s stability decreases with the Casson parameter. Further, it is remarkable to observe that without rotation, the Casson parameter has no impression on the magnitude of convection cells.

Experimental study on snow melting and deicing of carbon fiber heating roads considering thermal insulation conditions

Experimental study on snow melting and deicing of carbon fiber heating roads considering thermal insulation conditions

Exploring Impacts of Thermal and Lighting Conditions on Office Workers’ Subjective Evaluations, Cognitive Performance and EEG features in Multi-person Offices

Modern office workers spend lots of time in multi-person offices. For human-centered building design and operation, it is essential to investigate the influence of coupled physical environments on occupants’ well-being and task performance. In this study, to assess impacts of thermal and lighting environments on brainworkers, experiments were conducted under 64 conditions of different temperature, correlated color temperature, and illumination in a multi-person office. Electroencephalogram (EEG) signals were collected to measure the mental state of brainworkers and neurobehavioral tests were utilized to replicate cognitive tasks. The results indicated that only the interaction between the temperature and illumination regarding the sensation of CCT was significant. Primarily, lower illumination in colder environments made subjects perceive the lighting was warmer. Furthermore, cross-domain effects influenced office workers’ sensation via synesthetic effects. And the validity of the hue-heat hypothesis on thermal sensation depended on whether subjects received enough stimulation. Besides, for brainworkers, visual comfort peaked at 5000 K and 750 lux but the optimal temperature varied based on specific requirements, with 24 °C promoting overall comfort and 26 °C enhancing executive cognitive performance. The study preliminarily explored the effects among acceptable levels of T, CCT, and I on EEG features, revealing that temperature could adjust occupants’ mental load. However, the further investigation requests equipment with finer temporal granularity, cost-effective techniques and advanced analytical methods to guide office building design and operation.

Exploring impacts of thermal and lighting conditions on office workers’ subjective evaluations, cognitive performance and EEG features in multi-person offices

Modern office workers spend lots of time in multi-person offices. For human-centered building design and operation, it is essential to investigate the influence of coupled physical environments on occupants' well-being and task performance. In this study, to assess impacts of thermal and lighting environments on brainworkers, experiments were conducted under 64 conditions of different temperature, correlated color temperature, and illumination in a multi-person office. Electroencephalogram (EEG) signals were collected to measure the mental state of brainworkers and neurobehavioral tests were utilized to replicate cognitive tasks. The results indicated that only the interaction between the temperature and illumination regarding the sensation of CCT was significant. Primarily, lower illumination in colder environments made subjects perceive the lighting was warmer. Furthermore, cross-domain effects influenced office workers' sensation via synesthetic effects. And the validity of the hue-heat hypothesis on thermal sensation depended on whether subjects received enough stimulation. Besides, for brainworkers, visual comfort peaked at 5000 K and 750 lux but the optimal temperature varied based on specific requirements, with 24 °C promoting overall comfort and 26 °C enhancing executive cognitive performance. The study preliminarily explored the effects among acceptable levels of T, CCT, and I on EEG features, revealing that temperature could adjust occupants’ mental load. However, the further investigation requests equipment with finer temporal granularity, cost-effective techniques and advanced analytical methods to guide office building design and operation.

Evaluation of heat transfer conditions during polydisperse gas–solid flow in an industrial fluidised bed reactor

Knowledge of heat transfer conditions in large-scale circulating fluidised bed reactors plays an essential role in their proper design and optimization of theirs. This work presents an evaluation of the heat transfer conditions taking into account the coordinate height of the furnace chamber and the fluidised bed flow regime in the reactor. Experimental tests used method and measurement technique that provides reliable temperature data. The vertical and horizontal temperature profiles were obtained at different 966MWth fluidised bed reactor operating conditions. Four characteristic areas can be distinguished in the furnace chamber: the bottom region with a high-temperature gradient from 10.6 °C/m to 22.7 °C/m; the dense region with a medium temperature gradient from 4.7 °C/m to 7.3 °C/m; the dilute area with the lowest temperature gradient from 0.7 °C/m to 3.1 °C/m and the exit region with a temperature gradient (4.3 °C ≤ grad T ≤ 9.6 °C) similar to dense region. The horizontal temperature profiles confirmed a core-annular flow structure inside the furnace chamber. At the pressure drop below 5 kPa, the low variation of average temperature (from ±0.7 °C to ±4.2 °C) inside the furnace chamber of the CFB reactor was observed. As a result of fly ash recirculation of 3.86 kg/s, the lowest temperature gradient 0.2 °C/m was achieved in the bottom region of the furnace chamber. In the range of bed material circulation rates of 32 to 68 were registered temperature fluctuations 115 °C. The experimental results also showed the variation of the bed temperature was small and kept at a very low level of ±13 °C whereas the fluidised bed reactor was operated with a fluidisation velocity range of 1.8 to 2.4. Obtained findings provide unique data on heat transfer conditions in industrial facilities and thus fill the gap in literature data for CFB reactors. Based on main tests carried out in a large-scale CFB reactor, it can be concluded that detailed experimental data on thermal conditions provide important information to validate guidelines and for verifying empirical relationships, which are used in the design, optimization, and scaling of heat transfer surfaces in commercial fluidised bed reactors.

Comparative Study of Natural Fibres to Improve Insulation in Wooden Beehives Using Sensor Networks

The beekeeping sector is increasingly focused on creating optimal and natural environments for honeybees to reduce dependence on external factors, especially given progressively hotter summers. Improving hive thermal conditions can enhance bee wellbeing and production. While pinewood hives are predominant, some have started using insulating materials like polystyrene. However, many synthetic materials, despite their excellent insulation properties, are incompatible with organic food production, requiring alternative solutions. This study compares the thermal insulation properties of various natural materials, including white and black agglomerated cork, wood fibres, and rock mineral wool. These materials are potentially compatible with organic food production. Additionally, the research evaluates cost-effective sensor networks to monitor bioclimatic variables in real time. Lab tests using a Langstroth-type hive with a controlled heat source were conducted, monitoring temperature and humidity inside and outside the hive. The results revealed that all selected materials provided similar thermal insulation, superior to a hive without insulation. This finding suggests that using natural materials can enhance hive thermal comfort (i.e., the material’s ability to maintain a stable internal temperature), thereby improving honeybee wellbeing and productivity in a manner compatible with organic food production.

Progress in enrichment methods for protein N-phosphorylation

Protein phosphorylation is one of the most common and important post-translational modifications that regulates almost all life processes. In particular, protein phosphorylation regulates the development of major diseases such as tumors, neurodegenerative diseases, and diabetes. For example, excessive phosphorylation of Tau protein can cause neurofibrillary tangles, leading to Alzheimer's disease. Therefore, large-scale methods for identifying protein phosphorylation must be developed. Rapid developmentin efficient enrichment methods and biological mass spectrometry technologies have enabled the large-scale identification of low-abundance protein O-phosphorylation modifications in, allowing for a more thorough study of their biological functions. The N-phosphorylation modifications that occur on the side-chain amino groups of histidine, arginine, and lysine have recently received increased attention. For example, the biological function of histidine phosphorylation in prokaryotes has been well studied; this type of modification regulates signal transduction and sugar metabolism. Two mammalian pHis kinases (NME1 and NME2) and three pHis phosphatases (PHPT1, LHPP, and PGAM5) have been successfully identified using various biological methods. N-Phosphorylation is involved in multiple biological processes, and its functions cannot be ignored. However, N-phosphorylation is unstable under acidic and thermal conditions owing to the poor chemical stability of the P-N bond. Unfortunately, the current O-phosphorylation enrichment method, which relies on acidic conditions, is unsuitable for N-phosphorylation enrichment, resulting in a serious lag in the large-scale identification of protein N-phosphorylation. The lack of enrichment methods has also seriously hindered studies on the biological functions of N-phosphorylation. Therefore, the development of efficient enrichment methods that target protein N-phosphorylation is an urgent undertaking. Research on N-phosphorylation proteome enrichment methods is limited, hindering functional research. Thus, summarizing such methods is necessary to promote further functional research. This article introduces the structural characteristics and reported biological functions of protein N-phosphorylation, reviews the protein N-phosphorylation modification enrichment methods developed over the past two decades, and analyzes the advantages and disadvantages of each method. In this study, both antibody-based and nonantibody-dependent methods are described in detail. Owing to the stability of the molecular structure of histidine, the antibody method is currently limited to histidine phosphorylation enrichment research. Future studies will focus on the development of new enrichment ligands. Moreover, research on ligands will promote studies on other nonconventional phosphorylation targets, such as two acyl-phosphates (pAsp, pGlu) and S-phosphate (pCys). In summary, this review provides a detailed analysis of the history and development directions of N-phosphorylation enrichment methods.

Trade-off in a reef-building coral after six years of thermal acclimation

There is growing evidence that reef-building corals can acclimate to novel and challenging thermal conditions. However, potential trade-offs that accompany acclimation remain largely unexplored. We investigated physiological trade-offs in colonies of a globally abundant coral species (Pocillopora acuta) that were acclimated ex situ to an elevated temperature of 31 °C (i.e., 1 °C above their bleaching threshold) for six years. By comparing them to conspecifics maintained at a cooler temperature, we found that the energy storage of corals was prioritized over skeletal growth at the elevated temperature. This was associated with the formation of higher density skeletons, lower calcification rates and consequently lower skeletal extension rates, which entails ramifications for future reef-building processes, structural complexity and reef community composition. Furthermore, symbionts were physiologically compromised at 31 °C and had overall lower energy reserves, likely due to greater exploitation by their host, resulting in an overall lower stress resilience of the holobiont. Our study shows how biological trade-offs of thermal acclimation unfold, helping to refine our picture of future coral reef trajectories. Importantly, our observations in this six-year study do not align with observations of short-term studies, where elevated temperatures were often associated with the depletion of energy reserves, highlighting the importance of studying acclimation of organisms at relevant biological scales.

Comparative Analysis of Thermal Adaptations of Extremophilic Prolyl Oligopeptidases

Prolyl oligopeptidases (POPs) from psychrophilic, mesophilic, and thermophilic organisms found in a range of natural environments are studied using a combination of protein structure prediction, atomistic molecular dynamics, and trajectory analysis to determine how the S9 protease family adapts to extreme thermal conditions. We compare our results with hypotheses from the literature regarding structural adaptations that allow proteins to maintain structure and function at extreme temperatures, and find that in the case of POPs, only a subset of proposed adaptations are employed for maintaining stability. The catalytic and propeller domains are highly structured, limiting the range of mutations that can be made to enhance hydrophobicity or form disulfide bonds without disrupting the formation of necessary secondary structure. Rather, we observe a pattern in which overall prevalence of bound interactions (salt bridges and hydrogen bonds) is conserved by using increasing numbers of increasingly short-lived interactions as temperature increases. This suggests a role for an entropic rather than energetic strategy for thermal adaptation in this protein family.