Radiation Intensity Research Articles

Thermal performance analysis of the novel medium-depth borehole heat exchanger (MDBHE) coupled photovoltaic photothermal (PV/T) heat pump domestic hot water supply system

ABSTRACT As global energy demand continues to rise and traditional energy sources increasingly fail to meet sustainability targets, conventional domestic hot water systems that rely exclusively on either geothermal or solar energy face inefficiencies and seasonal limitations. To tackle these issues, this study introduces an innovative domestic hot water supply system combining MDBHE with a PV/T heat pump and investigates its thermal performance. This system utilizes thermal energy to elevate the temperature of water extracted from the MDBHE, while supplying power through photovoltaic electricity. The results indicate that increasing the circulating water flow rate improves the heat extraction capacity of the MDBHE. However, this also leads to higher flow resistance and an increased power requirement for the circulating water pump. Additionally, at a circulating water flow rate of 32 m3/h, the system fails to extract heat from geothermal energy when the inlet temperature exceeds 34.5°C. Furthermore, with a PV/T module area of 2000 m2, solar radiation intensity of 600 W/m2, and MDBHE depth of 2000 m, the system can attain a maximum water supply temperature of 50.9°C, with solar energy contributing 63%. Moreover, the coefficient of performance (COP) of the system can reach 5.8, outperforming conventional systems.

Experimental investigation of enhanced thermal performance of solar air collectors through optimized selection of manufacturing materials: Energy, exergy, economic, and environmental analysis

AbstractThe current study aims to experimentally investigate the thermal performance of three identical solar air collectors manufactured from three different metals: aluminum, zinc, and steel. The study conducted environmental and economic analyses of the three proposed solar air collectors over a month. The aluminum solar air collector demonstrated superior performance, achieving a maximum thermal efficiency of 24.46%, while the steel and zinc solar air collectors recorded thermal efficiencies of 21.57% and 18.16%, respectively. The exergy efficiency ranges for aluminum from 0.95% to 13.54%, zinc absorber plate exhibits from 0.63% to 11.89%, and steel from 0.6% to 9.98%. The aluminum solar air collector revealed high monthly cost savings of about $1429.6/month, followed by zinc ($1203.8) and steel ($963.4) solar air collectors. Environmental analysis to showed savings entering the atmosphere per month showed that the aluminum reduced about 19,795 kg CO2/month, Zinc solar air heat 16,668 kg CO2/month, and the steel solar air collector recorded 13,339 kg CO2/month. In this study, the absorber plate made of aluminum was the most efficient material, followed by zinc and steel. That confirms its suitability for designing efficient solar air heating systems in areas with high solar radiation intensity, such as Tunisia, and provides a clear direction for future research and development in manufacturing solar air collectors.

Optical properties of a hollow cylindrical quantum wire in a parallel applied magnetic field

In this theoretical study, we investigate optical properties of a hollow cylindrical quantum wire in the presence of a homogeneous magnetic field. The magnetic field is applied parallel to the axis of the quantum wire. The investigations were achieved by solving the Schrödinger equation within the effective mass approximation. The optical properties studied were absorption coefficient (AC) of electromagnetic radiation and changes in refractive index (CRI) of the hollow cylinder. The parallel applied magnetic field lifts the degeneracy of states of opposite angular momentum (the ±|m|\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\pm |m |$$\\end{document} states, m being the angular momentum quantum number) known as the Zeeman splitting. As such, in the presence of magnetic field, AC splits into two branches, one corresponding to a transition involving the positive m states and the other corresponding to a transition involving the negative m states. Increase in intensity of the electromagnetic radiation reduces the magnitude of the AC. Presence of inner radius of the hollow cylindrical wire lowers transition energies. Apart from absorption due to the (m=0→±1)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(m=0 \\rightarrow \\pm 1)$$\\end{document} transitions, the presence of the inner radius also facilitates absorption due the (m=-1→0)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(m=-1\\rightarrow 0)$$\\end{document} transition as the magnetic field strength increases, a phenomenon that does not happen in solid cylindrical quantum wires. The presence of the inner radius also enhances AC in strong magnetic field. Increase in intensity of the electromagnetic radiation affects the CRI (here considered up to third order), introducing a normal dispersion region in an otherwise anomalous region. The parallel magnetic field also splits the CRI depending on the sign of the m states involved in the transitions.

Effects of Protected Cultivation on Agronomic, Yield, and Quality Traits of Yard-Long Bean (Vigna unguiculata ssp. unguiculata cv.-gr. sesquipedalis)

Protected cultivation is the sustainable approach to horticultural crop production under adverse climates. In this study, the performance of yard-long beans under three protected cultivations, including single-span polyhouse (SSP), five-span polyhouse (FSP), and insect-proof net house (IPN), is examined and compared to open field cultivation. The above protected cultivation can extend the harvest period of pods by 6–10 days, improve their quality, and increase yield by 15.6% to 25.1%, reducing the incidence and severity of thrips and Cercospora leaf spot, rust, and powdery mildew. Among them, yard-long beans grown in SSP are longer and straighter in shape and have the lowest incidence and severity of pests and diseases and the highest levels of total polyphenols, total sugar, soluble protein, starch, and fiber. This indicates that protected cultivation has broad application in the production of yard-long beans. Through full subset regression analysis (FSRA), we report here that the yield and of yard-long bean occurrences of pests and diseases were highly impacted by climatic factors, especially UV radiation intensity and air temperature. These results have considerable implications for improving pod yield and quality and green prevention and control of pests and diseases through optimizing facility structure and fertilizer management.

Bridging the gap: A comparative analysis of indoor and outdoor performance for photovoltaic-thermal-thermoelectric hybrid systems

This research evaluates the performance of a hybrid thermal-thermoelectric photovoltaic air collector system (PV/T-TE) through experimental investigations. By integrating photovoltaic (PV) panels with thermoelectric (TE) modules, the system aims to enhance efficiency and energy output by converting waste heat into additional electricity. The study examines the impact of radiation intensity, ranging from 455.65 to 795.18 W/m2, on the system's performance, utilizing output temperature (To) and plate temperature (Tp) as key metrics. Managing waste heat in PV technology remains a challenge, impacting efficiency. Traditional PV/T systems generate both electricity and thermal energy but suffer efficiency losses due to inadequate heat management. Integrating TE modules into PV/T systems offers a promising solution, but optimal configurations and performance impacts under varying conditions are underexplored. Limited research focuses on PV/T-TE hybrid systems, with most studies addressing PV-TE systems. The objectives of this research are to experimentally assess the impact of integrating TE modules on the thermal and electrical efficiency of PV/T systems under varying radiation intensities and air mass flow rates. The methodology involves setting up a PV/T-TE hybrid system, conducting experiments under controlled conditions, and analyzing key performance metrics. The study explores optimal TE module configurations and installation techniques to maximize heat transfer and electricity generation. Comparative analysis with conventional PV/T systems establishes the superiority of the hybrid system. Findings indicate significant benefits from incorporating TE modules, enhancing energy output and efficiency by maintaining optimal PV panel temperatures.

Sustainability index and a bibliometric of photovoltaic thermal with rectangular channel

The main challenge associated with solar panels is the need to reduce excessive heat and optimize efficiency to achieve stable conditions. Therefore, a combination of collector and cooling technologies, such as Photovoltaic Thermal (PVT) Technology, is needed to address this problem. This research used water-based rectangular channel to cool the PVT through the Ansys simulation method. A total of nine variations of mass flow rates, which ranged from 0.001 to 0.009 kg/s and six solar intensities between 500 W/m2 and 1000 W/m2 were used to achieve the optimal performance. An energetic analytical method with average Sustainability Index (SI) of 0.001-0.009 kg/s and 1.186 at 1000 W/m2 intensity were incorporated. Furthermore, the maximum average Waste Exergy Rasio (WER) value of 0.854 at a 500 W/m2 intensity was used to determine the flow rate. The highest average Exergetic Ecological Index (EcEI) value recorded was -0.687 at a 1000 W/m2 radiation intensity, while the highest average Improvement Potential (IP) value was 421.145 W. The results showed that the simulation serve as a valuable point of reference in the design and advancement of water-based rectangular channel within future PVT technology.

A model predictive control strategy of global optimal dispatch for a combined solar and air source heat pump heating system

Due to low-carbon transformation of heating sources in northern China, the combination of the solar heating system (SHS) and the air source heat pump (ASHP) has attracted widespread attention due to their significant low-carbon and energy-saving characteristics. Nevertheless, different outdoor meteorological parameters simultaneously affect both the SHS and the ASHP. The heat supply of the SHS is primarily influenced by solar radiation intensity, and the efficiency of the ASHP is mainly constrained by outdoor temperature. The dual uncertainty and volatility of the output capacities of these two heat sources pose significant challenges to their coordinated control. Previous research has primarily focused on traditional rule-based control (RBC) and feedback control, prioritizing the utilization of solar energy while employing ASHP to compensate for heating deficiencies. However, these methods ignore the variations in ASHP efficiency due to fluctuations in outdoor temperature, leading to low whole-system operating efficiency and limiting the flexibility and responsiveness of the control. In this paper, a model predictive control strategy of global optimal dispatch for a combined solar and ASHP (SASHP) heating system is proposed, which focuses on the flexibility and adaptability of dual heat source dispatch under different external conditions. A Temporal Convolutional Network (TCN) was used to establish a solar radiation intensity and load prediction model. A solar heat production prediction was realized by combining the mechanism model based on solar radiation intensity prediction; a two-step room temperature prediction model was established by introducing new input parameters in the load prediction. This strategy achieves globally optimal dynamic planning of the heat supply and duration of the SHS and ASHP systems by considering solar radiation, outdoor temperature, room temperature, and energy consumption, ensuring the efficient and stable operation of the system. Compared to RBC, experimental results indicated that under conditions of sufficient solar energy, the heating proportion of the SHS increased by 31.1 %, the average COP of the ASHP improved by 8.7 %, the energy-saving rate was 14.6 %, and the room temperature control was also more effective; whole-season simulation results showed an average energy-saving rate of 8.35 %.

Correlations between Bench-Scale and Large-Scale Extinction Metrics for Firefighting Foams

Locally weighted regressions (LWR) were calculated between MIL-PRF-24385 1.8 m diameter pool fire extinction results and various 19 cm pool fire metrics, as compiled in a recent database. The goal: to define correlations between bench and large-scale foam fire extinction experiments to improve bench-scale experiments to more rapidly screen the firefighting potential of environmentally-friendly foams. Bench-scale metrics included the area under the curve (AUC) for extinction time versus foam flow rate profiles, the average extinction times at binned foam flow rate ranges, and CO2-based extinction times, determined through tunable diode laser absorption spectroscopy (TDLAS) measurements above the pool fire. When cross-validation was implemented within the LWR algorithm, the AUC values, CO2-based extinction times, and extinction times for a flow rate-bin > 1500 ml/min showed the best correlations to large-scale data; however, the R2 values were all below 0.6, indicating a low level of correlation. Although differences between active versus passive firefighter and foam generation methods exist between the two scales, data accuracy and limited data are likely contributing the most to low R2 values. The LWR correlations are promising and can be improved with accurate data, providing confidence in bench-scale testing despite diminished radiation intensity and turbulence associated with larger fires.

Boosting electricity generation associated with Saudi Arabi buildings using PCM and PV cells on walls and roof leading to a sustainable building

In Saudi Arabia, where the majority of regions receive a minimum incident shortwave solar energy exceeding 4 kWh/(m2.year), there is a high potential for electricity generation and simultaneously, a challenge in building cooling. In this study, by adding photovoltaic (PV) on the roof and wall, as well as using phase change material (PCM) inside the walls, electricity production and energy consumption of Saudi residential buildings were investigated. Taking into account the effects of radiation on vertical and horizontal envelopes as well as phase change in PCM, the energy equation was solved using DesignBuilder to specify hourly energy consumption and electricity generation. When installing PV cells at the optimal tilt, incoming radiation to the cells increases. However, creating shadows on subsequent rows of cells diminishes the effective PV surface area. Surprisingly, calculations revealed that if PV cells are installed at zero angle, owing to installing more PV cells, up to 31% extra electricity is produced than when installed at the optimal tilt. As a side effect, the cooling load decreases by 5.1% due to reduced radiation intensity on the roof. The orientation of the walls significantly impacts both phase change material (PCM) and PV-associated electricity generation. Placing PCM on the east wall optimizes its performance, while walls containing PV panels perform best when facing south. To further enhance cooling and reduce electricity demand, phase change material was incorporated into both the roof and wall, resulting in a 2% reduction in overall electricity demand. Notably, in eight major populated areas across Saudi Arabia, under the constraint of the constant PV cell area, installing PV cells on the roof proves three times more advantageous than placing them on the walls.

Selection and performance evaluation of roof materials in arid oasis cities: The advantages of white polymer materials

Selecting the appropriate roofing material is crucial for addressing the urban heat island effects. However, uncertainty remains regarding the best roofing material for improving subsurface cooling during hot summers in temperate continental arid climates. Comparative studies on different roof materials under various climatic conditions are essential to determine the most effective heat mitigation strategies for arid oasis cities. We present a conceptual model to examine the relationship between roofing materials and their thermal mitigation capabilities in arid regions during hot summers, while assessing the influence of climate factors on their cooling performance. An experiment in Urumqi evaluated the subsurface heat mitigation capabilities of four roofing materials: white polymer materials (WPM), sod (SOD), asphalt (ASP), and solar photovoltaic panels (SPP). The results showed that the WPM provided the most effective subsurface cooling. Compared with SOD, ASP, and SPP, WPM showed the lowest subsurface temperature. Notably, the subsurface temperature of the WPM was minimally affected by climatic factors and showed no correlation with solar radiation intensity, precipitation, and cloudiness (P > 0.05), highlighting its superior cooling performance. WPM roofs are recommended for heat mitigation during hot summers in arid oasis cities owing to their low maintenance costs, ecological benefits, and superior cooling performance. This study highlights the subsurface cooling capabilities of various roofing materials and their interaction with climatic factors and provides valuable insights for heat mitigation strategies in arid regions.

Electromagnetic radiation of granite under dynamic compression

To elucidate the characteristics and mechanism of electromagnetic radiation in granite under impact loading, based on the quasi-static compression tests, this paper conducts dynamic compression experiments on granite using Hopkinson pressure bar and one-stage light-gas gun as loading methods. Combined with experimental and theoretical analyses, the relationship between mechanical and electromagnetic responses under impact loads of different intensities, and the time-domain signals of electromagnetic radiation generated by a single crack under different strain rates are studied. The intensity and frequency of electromagnetic radiation increase with the increasing compressive strain rate. According to the thermal activation theory, it reveals the microscopic mechanism of the transition from intergranular microcracks to transgranular microcracks in terms of strain sensitivity. It also serves as the physical basis for the increase in electromagnetic radiation intensity amplitude and frequency with increasing compressive strain rate. Transgranular microcracks are the primary cause of electromagnetic radiation generated by fractures.

Experimental study on surface temperature and emissivity of rotating turbine blades of a micro turbojet engine

The temperature of the rotating turbine blades of a turbojet engine must be known to assess the combustion state and improve turbine blade quality. Obtaining online temperature measurements of high-speed rotating turbine blades in high-temperature gas flow remains challenging. A multispectral radiation thermometry method without emissivity assumption is proposed to measure the temperature of high-speed rotating turbine blades of a micro turbojet engine. The relative radiative intensity is calculated by accounting for smooth changes in the wavelength using the moving narrowband method to determine the influence of emissivity on multispectral radiation thermometry results. The method’s performance in measuring the surface temperature of high-speed rotating objects is tested. The wavelength range of 970 nm to 1700 nm is selected because the radiation from gases is weaker in comparison to the radiation emitted by solid surfaces within this band. The spectral radiation of the turbine blade surface is measured at three rotational speeds: 38,000 r/min, 48,000 r/min, and 58,000 r/min. The results show that, unlike thermocouples that measure the temperature of the hot gas flow near the blade, multispectral radiation thermometry provides the average surface temperature with high consistency (with a deviation smaller than 50 K). Multispectral radiation thermometry can be applied to measure the surface temperature and emissivity of high-speed rotating objects, such as the blades of turbojet engines.

Computational fluid dynamics analysis of flat plate type solar collector under different fin variables to enhance air-based heat transfer

Purpose This study begins by outlining the core principles of how flat plate solar collectors (FPSC) operate and the underlying mechanisms of heat transfer. It underscores the pivotal role of fin patterns in enhancing convective heat transfer. Design/methodology/approach The primary objective is to examine the impact of diverse fin patterns on the thermal performance of FPSCs. The study involves the development of a 3D-CFD model for FPSC using the computational fluid dynamics (CFD) software ANSYS FLUENT. The analysis is conducted for variable mass flow rates (mf) ranging from 0.01 to 0.05 kg/s with an interval of 0.02 kg/s. Each flow rate is assessed for three distinct fin patterns: straight plate fins, V-shaped fins and wavy fins. Recognizing the variation in solar radiation intensity throughout the day, the analysis is executed at six different time points ranging 10:00 a.m. to 03.00 p.m. with a time interval of 1.00 h. Findings It is observed that the wavy fin pattern with a mass flow rate of 0.01 kg/s exhibited the highest outlet temperature, showing a significant temperature difference of 12.4 K at noon. Conversely, the V-shaped fin pattern with a mf of 0.05 kg/s has the lowest temperature difference value, measuring only 3 K. The analysis included the calculation of thermal efficiency for each case, revealing that the V-shaped fin pattern at a mf of 0.05 kg/s and a sun radiation intensity of 885.42 W/m2 achieved the maximum instantaneous thermal efficiency (ηth) of 34.7%. The study records the outlet air temperature for all of these combinations and presents the data graphically in the paper. Originality/value The findings of the simulations indicate that the thermal performance that is ηth and maximum temperature of outlet air of FPSCs can be improved through the utilization of variable fin patterns.

Energy Advantages and Thermodynamic Performance of Scheffler Receivers as Thermal Sources for Solar Thermal Power Generation

This article examines the prospects of Scheffler solar receivers integrated into renewable energy power plants for civil applications. This kind of solar receiver can offer satisfactory energetic performance with acceptable energy conversion efficiency when compared to other technologies to harness solar energy since the high-quality focal receiver can reduce heat losses also supposing great levels of evaporation temperature. In this research, energetic optimization and a broad assessment of Scheffler-type solar receivers are thoroughly conducted for variable sun radiation and considering a broad range of working conditions. To achieve this goal, thermodynamic optimization of the chief factors was attained via a numerical model which calculated the energy efficiency of the Scheffler solar receiver at part-load working conditions by computing all energy losses negatively affecting the heat exchange phase in the cavity receiver. The results obtained in this study show that the solar collector efficiencies of Scheffler receivers appear more promising than that of usual parabolic trough collectors; moreover, Scheffler receivers persisted with less sensitivity to reductions in solar radiation intensity. For these reasons, solar power systems based on Scheffler-type systems can be used from tens to hundreds of kW to ensure the energetic supply of small urban settlements with acceptable efficiency, optimistic investments, simple construction and reduced overall sizes.

Metabolomic Analysis of Elymus sibiricus Exposed to UV-B Radiation Stress

Plants cultivated on the Qinghai-Tibet Plateau (QTP) are exposed to high ultraviolet radiation intensities, so they require effective mechanisms to adapt to these stress conditions. UV-B radiation is an abiotic stress factor that affects plant growth, development, and environmental adaptation. Elymus sibiricus is a common species in the alpine meadows of the QTP, with high-stress resistance, large biomass, and high nutritional value. This species plays an important role in establishing artificial grasslands and improving degraded grasslands. In this study, UV-B radiation-tolerant and UV-B radiation-sensitive E. sibiricus genotypes were subjected to simulated short-term (5 days, 10 days) and long-term (15 days, 20 days) UV-B radiation stress and the metabolite profiles evaluated to explore the mechanism underlying UV-B radiation resistance in E. sibiricus. A total of 699 metabolites were identified, including 11 primary metabolites such as lipids and lipid-like molecules, phenylpropanoids and polyketides, organic acids and their derivatives, and organic oxygen compounds. Principal component analysis distinctly clustered the samples according to the cultivar, indicating that the two genotypes exhibit distinct response mechanisms to UV-B radiation stress. The results showed that 14 metabolites, including linoleic acid, LPC 18:2, xanthosine, and 23 metabolites, including 2-one heptamethoxyflavone, glycyrrhizin, and caffeic acid were differentially expressed under short-term and long-term UV-B radiation stress, respectively. Therefore, these compounds are potential biomarkers for evaluating E. sibiricus response to UV-B radiation stress. Allantoin specific and consistent expression was up-regulated in the UV-B radiation-tolerant genotype, thereby it can be used to identify varieties resistant to UV-B radiation. Different metabolic profiles and UV-B radiation response mechanisms were observed between the UV-B radiation-tolerant and UV-B radiation-sensitive E. sibiricus genotypes. A model for the metabolic pathways and metabolic profiles was constructed for the two genotypes. This metabolomic study on the E. sibiricus response to UV-B radiation stress provides a reference for the breeding of new UV-B radiation-tolerant E. sibiricus cultivars.

On the Physical Nature of Lyα Transmission Spikes in High-redshift Quasar Spectra

We investigate Lyman-alpha (Lyα) transmission spikes at 5.2 < z < 6.8 using synthetic quasar spectra from the “Cosmic Reionization on Computers” simulations. We focus on understanding the relationship between these spikes and the properties of the intergalactic medium (IGM). Disentangling the complex interplay between IGM physics and the influence of galaxies on the generation of these spikes presents a significant challenge. To address this, we employ Explainable Boosting machines, an interpretable machine learning algorithm, to quantify the relative impact of various IGM properties on the Lyα flux. Our findings reveal that gas density is the primary factor influencing absorption strength, followed by the intensity of background radiation and the temperature of the IGM. Ionizing radiation from local sources (i.e., galaxies) appears to have a minimal effect on Lyα flux. The simulations show that transmission spikes predominantly occur in regions of low gas density. Our results challenge recent observational studies suggesting the origin of these spikes in regions with enhanced radiation. We demonstrate that Lyα transmission spikes are largely a product of the large-scale structure, of which galaxies are biased tracers.

Estimation of Longwave Radiation Intensity Emitted from Urban Obstacles in Each Direction Using Drone-Based Photogrammetry

Longwave radiation is a crucial factor affecting human thermal comfort and thermal stress, especially in outdoor spaces in summer, owing to the vast effect of longwave radiation emitted from high-heated asphalt roads, building walls, and automobiles. Although controlling the longwave radiation environment to improve thermal comfort in summer is crucial, the prediction of the longwave radiation environment is frequently conducted only at the assessment stage of the final proposal because of the high computational cost of radiation calculations and unsteady heat balance analysis considering multiple reflections. This is a significant constraint for the design of urban and architectural environments. A previous study proposed a method to rapidly estimate the longwave radiation environment based on a point-by-point method with longwave radiation intensity distributions of the heat sources. To use this method, 3D models of the geographical objects in urban areas, such as buildings and trees, must be accurately generated, and these models should have information on the longwave radiation emitted in each direction from each object. However, no specific examples of a 3D model and longwave radiation intensity distribution have been presented. In this study, a 3D modeling method for geographical objects in urban areas with longwave radiation information based on drones and photogrammetric techniques was utilized. Moreover, a 3D model of a small-scale building was generated. A longwave radiation intensity distribution was produced for the building. Based on the distribution data, the directional characteristics of longwave radiation were discussed, and the availability of the proposed method was assessed.

High-sensitivity multi-gas detection using dual-ridge metasurface emitters with polarization-distinguishable emission spectra

The metasurface thermal emitter offers an energy-efficient, compact, and sensitive solution as a radiation source for non-contact gas detection, enabling the “molecular fingerprint” technique to be widely applied, from medical diagnostics to environmental monitoring. However, most narrowband emitters are designed for a single target gas, hindering the miniaturization of multi-gas detection systems. In this work, a one-dimensional dual-ridge grating emitter is employed, achieving dual-band and tri-band polarization-distinguishable emission spectra through the excitation of Fabry-Perot (FP) resonances and quasi-bound states in the continuum (qBICs). These emission spectra can be readily matched to multiple non-overlapping absorption peaks of gases such as CH4, CO2, CO, NO, and NH3 within the 3–6 µm range, thereby reducing the impact of mixed gases on measurements. Compared to conventional metal-dielectric-metal structures, the use of a single metal layer results in lower material losses, enabling higher Q-factors and more pronounced directional radiation intensity variations. Furthermore, adjusting the asymmetry to modulate the qBIC-excited absorption peaks does not affect the Q-factor of the FP resonance absorption, thus achieving high-sensitivity multi-band gas detection. This work provides a promising approach for the miniaturization and integration of multi-gas channel detection, facilitating more accurate and sensitive sensing strategies.

Thermal Performance of Novel Eco-Friendly Prefabricated Walls for Thermal Comfort in Temperate Climates

The global threat of climate change has become increasingly severe, with the efficiency of buildings and the environment being significantly impacted. It is necessary to develop bioclimatic architectural systems that can effectively reduce energy consumption while bringing thermal comfort, reducing the impact of external temperatures. This study presents the results of a real-scale experimental house prototype, MHTITCA, using a unique design composed of novel eco-friendly prefabricated channel walls filled with a blend of soil, sawdust, and cement for walls and roofs. The experimental analysis performed in this study was based on dynamic climatology. A solar orientation chart of the place was constructed to identify the solar radiation intensity acting on the house. Measurements of roof surface temperatures were conducted to determine temperature damping and temperature wave lag. Monthly average temperature and direct solar radiation data of the site were considered. Compared to other alternative house prototypes, the system maximizes thermal comfort in high-oscillation temperate climates. Temperature measurements were taken inside and outside to evaluate the thermal performance. A thermal insulating layer was added outside the wall and the envelope to improve the prototype’s thermal comfort and reduce the decrement factor even more. This MHTITCA house prototype had 85% thermal comfort, 0% overheating, and 15% low heating. This eco-friendly prototype design had the best thermal performance, achieving a thermal lag of twelve hours, a reduced decrement factor of 0.109, and preventing overheating in areas with high thermal fluctuations. Comparatively, the other prototypes examined provided inferior thermal comfort. The suggested MHTITCA system can be an energy-saving and passive cooling option for thermal comfort in low-cost houses in temperate climates with high thermal oscillations in urban or rural settings.

Layered Perovskite La2Ti2O7 Nanostructures for Photocatalytic Degradation of Congo Red Dye Pollutant

AbstractIn photocatalytic innovation, there has been a lot of interest in creating broad spectral responsive photocatalysts to get superior catalytic performance. In this study, we synthesized highly visible‐light responsive La2Ti2O7 perovskite photocatalysts by the probe ultrasonication procedure followed by high‐temperature calcination. Such materials are characterized using UV‐vis diffuse reflectance spectra, powder X‐ray diffraction, X‐ray photoelectron spectroscopy, and scanning electron microscopy to illustrate the optical absorption activities, crystalline properties, chemical composition, and microscopic features. La2Ti2O7 extends optical absorption towards the visible light spectrum and narrows the band gap. The photocatalytic efficacy of the resulting La2Ti2O7 nanostructures was investigated by performing photocatalytic degradation of persistent Congo red (CR) dye while subjected to visible photon illumination using three Osram 150 W tungsten halogen lamp ((λ≥400 nm), 5000 lm nominal luminous flux, 80,600 lx radiation intensity. With effective efficiency, the optimum degradation of the 10 ppm CR dye with a percentage of 95.9 was achieved after 90 min during exposure to the La2Ti2O7 perovskite with a catalyst dosage of 30 mg/100 mL at pH 6. Consequently, La2Ti2O7 nanostructures alone depicted 19.8 % adsorption efficiency for CR dye. In addition, OH⋅ and holes were important in degrading CR dye, which included many different reaction pathways. The treated solution can also demonstrate the environment's safety for accepting water. In summary, under natural visible light irradiation, the synthesized La2Ti2O7 showed enormous promise for eliminating different organic contaminants using photocatalytic methodology.