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The article discusses a research collaboration between PCI and Oak Ridge National Laboratory (ORNL) on next-generation materials for architectural precast insulated wall panels. The project aimed to develop lighter panels with higher thermal performance and a shorter production time. The research focused on developing a concrete mixture with reduced density and early tensile strength, as well as noncorroding inserts for the panels. The collaboration has led to further research opportunities in the precast concrete industry. [Extracted from the article]

Power transformer insulating oil is essential to the transformer's usable life. Mineral base transformer insulation oil is the most commonly used type; however, biodegradable alternatives have been developed due to safety and environmental concerns. This paper improves the insulation properties of power system transformers through the utilization of natural liquid-based insulation with additives. This work aims to enhance the functionality and dependability of transformer insulation-based vegetable seed oil for power system analysis. Here, vegetable seed oil-based natural liquid is used, which includes soybean oil, maize oil, mustard oil, and rice bran oil, which are chosen for analysis together with artificial and natural antioxidants like propyl gallate and citric acid. Blending vegetable seed oil with mineral oil of different compositions and adding additional 0.5 g and 1 g of additives allows for the analysis of the property improvement. The different properties, both with and without the influence of additives, are assessed in accordance with IEC/ASTM standards for breakdown voltage, water content, flash point, fire point, acidity, viscosity, and interfacial tension. The results demonstrate that the proposed natural liquid-based insulation with additives exhibits superior electrical and thermal properties compared to conventional insulation systems. It shows enhanced dielectric strength, improved thermal conductivity, and better resistance to ageing effects. These improvements give the reliability and efficiency of power system transformers. The findings indicate that the proposed insulation system offers significant environmental benefits compared to traditional mineral oil-based insulation. [ABSTRACT FROM AUTHOR]

Highlights This study investigates the mechanical properties and erosion resistance of high temperature–pressure carbon‐epoxy novolac insulation reinforced with ZrB2/SiC particles. For this reason, at first, five samples were fabricated using the hot press, which included resin epoxy novolac EPN1180 base without reinforcement and four samples containing resin with 20:80, 30:70, 40:60, and 50:50 of SiC: ZrB2 particles respectively. After manufacturing of the samples, the mechanical properties were evaluated through bending and tensile testing, followed by erosion resistance properties by the use of oxyacetylene flame erosion tests. Chemical composition and surface morphology analysis of the composites were conducted using energy‐dispersive spectroscopy, scanning electron microscopy, and x‐ray diffraction analysis. Results indicate that the addition of ceramic particles enhances both mechanical properties and erosion resistance of the composite. The pure resin sample exhibited the highest weight loss and thickness reduction, while the sample containing 40% SiC and 60% ZrB2 demonstrated the least weight loss and thickness reduction about 55% and 83% respectively compared to pure sample. Additionally, the sample with 30% SiC and 70% ZrB2 had the lowest backside temperature. Furthermore, the sample with 20% SiC and 80% ZrB2 exhibited the highest mechanical properties, with a tensile strength of 422.5 MPa and flexural strength of 587.11 MPa. Morphological analysis revealed the presence of phases such as SiO2, ZrO2, and ZrSiO4 attributable to the ZrB2/SiC particles, contributing to the enhancement of erosion resistance. Examines volume ratios of ZrB2/SiC. Discovers the best particle ratio (20%SiC, 80%ZrB2) for mechanical properties. Identifies the best particle ratio (30% SiC, 70% ZrB2) for erosion resistance. Reveals key phases enhancing erosion resistance with advanced analysis methods. Linear and mass ablation rate improved by 83% and 55% (best formation). [ABSTRACT FROM AUTHOR]

The external building walls are significant in mitigating adverse weather conditions. Current research on the thermal insulation of exterior walls often overlooks crucial factors such as human comfort, seasonal changes and environmental dynamics. This study introduced a performance evaluation approach for external walls that considered the human thermal zone, annual air temperature and solar radiation. Taking Nanjing City as a case study, the thermal insulation performance of five distinct types of building exterior walls was investigated. The findings highlight the impact of various insulated wall systems on thermal insulation. While different insulated walls exhibited significant variations in effectiveness during extreme weather episodes, these variations were minor over the course of the year. Analysis revealed a spectrum of performance for insulated exterior walls, ranging from excellent to poor: Outer Insulated Wall > Inside Insulated Wall = Sandwich Insulated Wall = Self-Insulated Wall > Mortar-Insulated Wall. The disparity in thermal insulation performance amongst four wall types was minimal, with the mortar-insulated wall demonstrating the lowest performance. The highest temperature recorded for the mortar-insulated wall surpassed 32.2°C over 68 days. This research contributes insights into the nuanced performance of various insulated walls, paving the way for decision-making in climate resilience strategies. [ABSTRACT FROM AUTHOR]

Svalbards permafrost is thawing as a direct consequence of climate change. In the Low Arctic, vegetation has been shown to slow down and reduce the active layer thaw, yet it is unknown whether this also applies to High Arctic regions like Svalbard where vegetation is smaller, sparser, and thus likely less able to insulate the soil. Therefore, it remains unknown which components of High Arctic vegetation impact active layer thaw and at which temporal scale this insulation could be effective. Such knowledge is necessary to predict and understand future changes in active layer in a changing Arctic. In this study we used frost tubes placed in study grids located in Svalbard with known vegetation composition, to monitor the progression of active layer thaw and analyze the relationship between vegetation composition, vegetation structure and snow conditions, and active layer thaw early in summer. We found that moss thickness, shrub and forb height, and vascular vegetation cover delayed soil thaw immediately after snow melt. These insulating effects attenuated as thaw progressed, until no effect on thaw depth was present after 8 weeks. High Arctic mosses are expected to decline due to climate change, which could lead to a loss in insulating capacity, potentially accelerating early summer active layer thaw. This may have important repercussions for a wide range of ecosystem functions such as plant phenology and decomposition processes. Plain Language Summary: Temperatures are rising in the Arctic, causing increased thaw of the layer of soil located above the permanently frozen ground. In Low Arctic regions vegetation cools the soil, which reduces the thawing. So far, we do not know whether the small plants growing in the High Arctic may be able to slow or reduce thaw. We measured soil thaw throughout the summer in High Arctic Svalbard in locations where vegetation composition is known. We also measured thickness of the moss layer, height of plants and snow depth. We found that moss thickness was the strongest factor in insulating the soil. Also the cover of plants, height of shrubs and forbs, and height of grass‐like plants slowed soil thaw in the early summer. The insulating effects became less over time and no effects were found 8 weeks after onset of thaw. As climate change is causing changes in the Arctic vegetation, mosses and small shrubs are expected to decrease. As we found these to be the most important factors in insulating the soil, a future decrease in mosses and small shrubs may cause accelerated soil thaw at the start of summer. Key Points: High Arctic vegetation slows active layer thaw in early summer after snow meltMosses show a stronger negative relation with thaw depth than vascular vegetationFactors influencing active layer thaw change over time in early summer [ABSTRACT FROM AUTHOR]

Abstract Transformer is a well-known power system apparatus utilized in conjunction with solid insulations such as paper and press board, as well as liquid insulations like mineral oil, a petroleum-based fluid. Despite the notable drawbacks associated with mineral oil, such as limited resources for future generations and its non-eco-friendly nature, its usage remains ubiquitous. There is a growing imperative to explore alternative fluids that surpass mineral oil in terms of environmental impact and performance. Amidst the global shift towards green energy, this study focuses on vegetable seed oils such as corn oil, soybean oil, mustard oil, and rice bran oil as potential substitutes. The research evaluates these oils based on key transformer properties including breakdown voltage, water content, interfacial tension, viscosity, acidity, flash point, and fire point. Interestingly, rice bran oil and soybean oil exhibit promising characteristics that suggest they could effectively replace petroleum-based fluids in transformers. Furthermore, the study extends to blending mineral oil with vegetable seed oils in various compositions, incorporating natural and synthetic antioxidant additives ranging from 0 to 1%. Comparative analyses between samples with and without additives reveal that the inclusion of 1% propyl gallate yields outstanding performance improvements. For instance, a blend comprising 25 ml of mineral oil and 25 ml of soybean oil, supplemented with 1% propyl gallate, demonstrates 90% higher effectiveness compared to other blends and additives tested. Moreover, the research employs statistical regression analysis to establish relationships between different parameter variables, providing deeper insights into the performance and compatibility of these blended oils in transformer applications. This comprehensive investigation underscores the potential of vegetable seed oils as viable alternatives to mineral oil, contributing to the advancement of eco-friendly solutions in power systems.

In the last decade, growing efforts were made to replace crosslinked XLPE insulations with thermoplastic ones in high-voltage DC cables. The main reason for these development projects is the injection and trapping of charge carriers under DC conditions, leading to a field distribution within the insulation layer different from HVAC cables. Thermoplastic cable insulation is favorable in many respects, except for its thermal stability. So far, HDPE/LDPE and binary or ternary PP-based blends have been tried. The former offers a limited advantage in heat resistance, while the latter is too hard at high PP contents and loses thermomechanical properties at high elastomer contents. In this paper, the compatibility of binary polyolefin blends is first briefly reviewed; then, the cable-specific properties are presented together with examples taken from the literature. Deep trap formation, low conductivity, and optimum breakdown properties are observed in HDPE/LDPE blends under specific crystallization conditions where a fine-grained structure is formed. It results in a proper concentration of the traps, but these are not accumulated at the spherulite boundaries. Trap density and energy are also modulated by the relaxation processes. The future belongs to the PP-based blends, where several compatibilizing agents (copolymers, elastomers, in situ reactions) have been tried to find the balance between electrical, mechanical, and thermal properties. In these materials, again, fine, close to co-continuous structures should be achieved to reach the required properties, but the aromatic and polar comonomer content also contributes to the formation of deep traps in relatively uniform distribution. The PP phase must remain continuous to maintain the necessary thermomechanical properties above the Tg of the soft components.

In this paper, the heat treatment of alumina fiber was studied. The infiltration agent on the fiber surface was removed after heat treatment at 450 °C for 6 h. TG-DSC, scanning electron microscope, x-ray diffraction, Fourier infrared spectrometer, energy dispersive spectrometer, and patterning were used to analyze the thermal weight loss, fiber surface morphology, crystal structure, and composition of alumina fibers. The results show that the aluminum oxide fiber has excellent temperature resistance and does not undergo crystal phase transformation during thermal weight loss. After heat treatment, the fiber surface infiltration agent ablates and dissolves from the fiber surface, and the internal crystal structure of the fiber remains stable. The tensile testing machine was utilized to test the breaking strength of alumina fiber. The fiber still maintained high strength after heat treatment, and the retention rate of breaking strength was greater than 74%. ZC-90G high insulation resistance measuring instrument and WDY-Ⅱ automatic voltage tester were utilized to analyze the insulation resistivity and breakdown strength of alumina fiber before and after heat treatment. The results show that heat treatment can effectively improve the insulation performance and breakdown strength of alumina fiber. [ABSTRACT FROM AUTHOR]

Abstract Background To reduce heat loss underwater, marine mammals cover their bodies with insulation. Cetaceans in particular rely solely on blubber for insulation which has low conductivity. Blubber establishes a great thermal gradient between the warmer body core and cooler body surface, reducing heat transfer to the environment. A temperature gradient within the blubber determines the conductive heat transfer from the body trunk, where conduction and convection are the primary heat transfer mechanisms in cetaceans. Therefore, measuring the temperature at the innermost part of the blubber, i.e., the temperature at the muscle–blubber interface (Tmbi), can enhance our understanding of thermoregulatory mechanisms in cetaceans. In thermoregulation, activity-induced heat produced by increased muscle metabolism is another factor that plays an important role, however, the effects of activity on Tmbi have not been investigated in cetaceans. To assess this relationship in free-swimming cetaceans, we measured Tmbi and activity levels in a captive Risso’s dolphin (Grampus griseus) using an implantable biologging device. Results Tmbi and activity data were analyzed for 11 days. The average Tmbi was 35.1 ± 0.6 ºC and the temperature gradient between Tmbi and the water temperature was 13.0 ± 0.7 ºC. Tmbi was higher during the daytime and lower in the early morning. The variation in Tmbi was best explained by both the activity levels and time of day. Tmbi did not simply increase with activity levels; it appeared to remain relatively constant at most activity levels. However, Tmbi appeared to decrease when the animal was inactive and increase when it was intensely active. Conclusion Our results provide important insights into how a dolphin regulates its body temperature underwater. Thermal insulation by blubber and heat production by activity were suggested to play important roles in thermoregulation. Whole-body heat dissipation might be used to regulate temperature increases when heat production is excessive due to intense activity. During inactive periods, decreasing temperature gradient may help reduce heat loss from the body.

This study investigates the impact of insulation on energy consumption and CO2 emissions in high-rise commercial buildings across various climate zones. Through a simulation-based approach using the Hourly Analysis Program (HAP), the effectiveness of insulation in reducing energy demand and carbon emissions are evaluated. The research includes multiple climatic regions of Afghanistan, including arid, semi-arid, and mountainous zones. Methodologically, detailed building characteristics, climatic data, and insulation materials are considered, with energy modeling techniques applied to assess the performance of insulation measures. Results indicate varying degrees of energy savings and CO2 emissions reduction associated with insulation across different climate zones, in cities such as Kabul, Herat, Mazar, and Kandahar. Furthermore, the study calculates CO2 emissions reduction resulting from insulation addition, emphasizing the importance of sustainable building practices in mitigating environmental impacts. By underscoring the scientific value of this research in addressing a pressing global challenge and providing actionable insights for building design and energy policy, this study contributes to the advancement of knowledge in the field of sustainable construction and environmental engineering.

The building and construction industry consumes a significant amount of natural resources alongside contributing to the generation of waste materials. Addressing the dual challenge of waste management and recycling in this sector is imperative. This study begins with a bibliometric assessment to identify waste materials used as insulation in building and construction systems. The assessment of 2627 publications revealed mattress waste materials were seldom considered. The aim of this research focuses on exploring alternative methods for repurposing mattress materials in construction, aiming to mitigate waste generation. While various materials are being recycled for building applications, this research emphasises the potential of incorporating recycled polyurethane foam (PUF) from mattresses as insulation products. A transient plane source (TPS) was employed to determine the thermal conductivity of waste mattress PUF obtained from a recycling plant in Victoria, Australia. The results exhibited promising thermal resistance, with a mean value of 0.053 Wm/K. However, optimal thermal performance was observed with increased thickness, suggesting that a thickness of 215mm aligns with industry standards for building fabric systems. Further research is required to comprehensively analyse moisture resistance and fire retardation of waste mattress materials. This paper presents key findings of current trends, limitations, and future research directions to the use of waste mattress PUF as an insulation material.

Background: To reduce heat loss underwater, marine mammals cover their bodies with insulation. Cetaceans in particular rely solely on blubber for insulation which has low conductivity. Blubber establishes a great thermal gradient between the warmer body core and cooler body surface, reducing heat transfer to the environment. A temperature gradient within the blubber determines the conductive heat transfer from the body trunk, where conduction and convection are the primary heat transfer mechanisms in cetaceans. Therefore, measuring the temperature at the innermost part of the blubber, i.e., the temperature at the muscle–blubber interface (Tmbi), can enhance our understanding of thermoregulatory mechanisms in cetaceans. In thermoregulation, activity-induced heat produced by increased muscle metabolism is another factor that plays an important role, however, the effects of activity on Tmbi have not been investigated in cetaceans. To assess this relationship in free-swimming cetaceans, we measured Tmbi and activity levels in a captive Risso's dolphin (Grampus griseus) using an implantable biologging device. Results: Tmbi and activity data were analyzed for 11 days. The average Tmbi was 35.1 ± 0.6 ºC and the temperature gradient between Tmbi and the water temperature was 13.0 ± 0.7 ºC. Tmbi was higher during the daytime and lower in the early morning. The variation in Tmbi was best explained by both the activity levels and time of day. Tmbi did not simply increase with activity levels; it appeared to remain relatively constant at most activity levels. However, Tmbi appeared to decrease when the animal was inactive and increase when it was intensely active. Conclusion: Our results provide important insights into how a dolphin regulates its body temperature underwater. Thermal insulation by blubber and heat production by activity were suggested to play important roles in thermoregulation. Whole-body heat dissipation might be used to regulate temperature increases when heat production is excessive due to intense activity. During inactive periods, decreasing temperature gradient may help reduce heat loss from the body. [ABSTRACT FROM AUTHOR]

This study investigates the effect of positive temperature coefficient (PTC) fillers, i.e., barium strontium titanate (BST‐60) and nano hexagonal boron nitride (h‐BN) fillers, on thermal and dielectric insulation properties of epoxy (EP). The electrical resistivity, DC breakdown strength, space charge, thermal conductivity, thermogravimetric analysis, and glass transition temperature (Tg) of EP composites were measured. Results indicate that, below curie temperature, the EP composites containing 0.5 and 1 wt% of BST and 5 wt% of h‐BN have superior electrical resistivity, breakdown strength, and thermal conductivity. However, above curie temperature, the EP composites containing 2 and 2.5 wt% of BST and 5 wt% of h‐BN have superior insulation properties than the pure EP and other composites. While the thermal properties of EP improve with an increase in h‐BN loading to 10 wt%, its dielectric properties are slightly compromised due to the presence of tiny defects in the composite material. It is hypothesized that the BST‐60 suppresses the negative temperature coefficient effect (NTC) of EP by regulating the electrical resistivity above the curie point, whereas nano h‐BN enhances the thermal conductivity of EP by constructing a heat dissipation path. The proposed mechanism for charge dynamics along with heat conduction‐dissipation explains the fillers' behavior at different temperatures. Highlights: Analysis of epoxy composites with polydopamine‐modified BST and h‐BN fillers.PTC fillers are used to mitigate the negative temperature effect of epoxy.Optimal fillers wt% improves dielectric and thermal properties.This study shows that optimized epoxy composites can be used for packaging. [ABSTRACT FROM AUTHOR]

Functional energy-saving materials with coupled cooling effect have become particularly urgent because traditional cooling systems require high industrial energy inputs and high labor costs. Biomass-derived materials are highly desirable for the environment and energy-related applications, but raw biomass materials cannot satisfy cooling demands for more environment and energy-efficient processes. Herein, inspired by the transpiration of natural plants and radiation cooling of metal materials, this study presents the silver nanoparticles–coated wood with a coupled cooling effect for dual-mode cooling. The silver nanoparticles–coated wood with a natural hollow ordered pore structure can achieve the cooling effect by the capillary phenomenon where water absorption and evaporation. The results revealed that silver nanoparticles with high infrared reflectivity were firmly embedded in the surface of the wood by magnetron sputtering, which empowers the wood with high infrared heat dissipation properties. Compared to the bare porous wood, the surface temperatures of silver nanoparticles coated wood were decreased from 34.6–35.8 to 30.3–31.2 °C. In addition, by combining with the evaporative and radiative heat dissipation, the silver-coated wood obtained the coupled cooling effect under simulated solar radiation, which further improves the cooling effect. Owing to the silver coating, the material possesses an excellent antibacterial property which extends durability. Therefore, the tree-inspired water vapor evaporation and radiation cooling show good harmony and can be well combined by the directional structure design of the material. This dual-mode cooling mechanism provides a novel design concept of cooling materials and further promises to benefit the sustainability of society in many aspects, from health to economy. [ABSTRACT FROM AUTHOR]

By using 6,6-((sulfonylbis (4,1-phenylene)) bis (azanediyl)) bis (thiophen-2-ylm- ethylene)) bis (6H-di-benzo[c,e][1,2]oxaphosphinine 6-oxide (DOPO-N) as phosphorus-nitrogen flame retardant, the polyurea (PUA) with flame retardant properties (PUA/DOPO-N) was prepared. In addition, organically modified montmorillonite (OMMT) and magnesium hydroxide (MH) were used as co-effectors respectively, and the flame retardant PUA (PUA/DOPO-N/OMMT and PUA/DOPO-N/MH) were also prepared. Thermal properties, flame retardant properties, flame retardant mechanism and mechanical properties of PUA/DOPO-N, PUA/DOPO-N/OMMT and PUA/DOPO-N/MH were investigated by thermogravimetric (TG) analysis, limiting oxygen index (LOI), UL 94, cone calorimeter test, scanning electron microscopy (SEM), and tensile test. The results show that the LOI value of PUA/20%DOPO-N, PUA/18%DOPO-N/2%OMMT and PUA/15%DOPO-N/5%MH are 27.1%, 27.7%, and 28.3%, respectively, and UL 94 V-0 rating is attained. Compared with PUA, the peak heat release rate (pk-HRR), total heat release (THR) and average effective heat combustion (av-EHC) of PUA/20%DOPO-N, PUA/18% DOPO-N/2%OMMT and PUA/15%DOPO-N/5%MH decrease significantly. SEM results indicate that the residual chars of PUA/20%DOPO-N, PUA/18%DOPO-N/2%OMMT and PUA/15% DOPO-N/5%MH are completer and more compact. The complex of DOPO-N/OMMT and DOPO-N/MH have synergistic flame retardancy. The mechanical properties of PUA can be improved by the addition of DOPO-N, DOPO-N/OMMT and DOPO-N/MH, respectively. The insulation performance test shows that the volume resistivity of PUA/20%DOPO-N is 6.25×1016 Ω.cm. Furthermore, by using modified boron nitride (MBN) as heat dissipating material, the complex of PUA/MBN was prepared, and the thermal conductivity of PUA/MBN was investigated. The thermal conductivity of PUA/8%MBN complex coating at room temperature is 0.166 W/(M·K), which is a 163% improvement over pure PUA. [ABSTRACT FROM AUTHOR]

The building and construction industry consumes a significant amount of natural resources alongside contributing to the generation of waste materials. Addressing the dual challenge of waste management and recycling in this sector is imperative. This study begins with a bibliometric assessment to identify waste materials used as insulation in building and construction systems. The assessment of 2627 publications revealed mattress waste materials were seldom considered. The aim of this research focuses on exploring alternative methods for repurposing mattress materials in construction, aiming to mitigate waste generation. While various materials are being recycled for building applications, this research emphasises the potential of incorporating recycled polyurethane foam (PUF) from mattresses as insulation products. A transient plane source (TPS) was employed to determine the thermal conductivity of waste mattress PUF obtained from a recycling plant in Victoria, Australia. The results exhibited promising thermal resistance, with a mean value of 0.053 Wm/K. However, optimal thermal performance was observed with increased thickness, suggesting that a thickness of 215mm aligns with industry standards for building fabric systems. Further research is required to comprehensively analyse moisture resistance and fire retardation of waste mattress materials. This paper presents key findings of current trends, limitations, and future research directions to the use of waste mattress PUF as an insulation material. [ABSTRACT FROM AUTHOR]

Precast concrete sandwich wall panels (PCSPs) are popular for building exteriors due to their high thermal efficiency, composite performance, and low manufacturing and maintenance costs. Researchers have investigated the possibility of reducing the panel thickness while maintaining the cladding components' thermal efficiency and strength to further improve efficiency and to reduce material consumption. However, limited research has been conducted on the shear bonding of steel plates, which is critical to ensuring durability and energy efficiency. This study investigated the shear behaviour of PCSPs with an S-type shear connector (SSC) through nine push-off tests and non-linear finite element modelling using Abaqus. Parametric studies were carried out to investigate the influence of the geometric properties of the SSC, the yield strength of the steel and the insulation thickness. The results suggest that the maximum secant stiffness for SSCs was achieved at a width of 101.4 mm and a thickness of 2 mm. Therefore, it is recommended that the width of the SSCs be limited to this value or less. Furthermore, the study found that increasing the yield strength of the steel beyond a thickness of 2 mm and a width of 101.4 mm did not improve the results and had a negative impact on the secant stiffness of the SSCs. [ABSTRACT FROM AUTHOR]

Cooling system is in charge of a high percent of total energy consumption in buildings. Different cooling systems and devices have different effects on the cooling load and energy consumption. The main objective of this paper is to study the effects of floor and ceiling temperature in comparison with other parameters including location of air diffusers and application of insulation and sealant. On the other hand, hospitals are huge buildings with high energy requirements and systems compared to other buildings such as universities, schools and offices. In this paper the impacts of these different cooling parameters on the temperature and cooling load in a room of a hospital are studied using Design of Experiments (DOE) and the Taguchi method. The experiments are simulated in Energy Plus to achieve the comfort temperature in one hospital’s room in Iran during six months of spring and summer. Using different cooling systems such as chilled floor (during night to decrease the peak load during day) and ceiling in combination with air handling unit can provide people satisfaction while optimizing energy consumption. The results show that the location of inlet and outlet diffusers has the most effect while the chilled floor (when the other systems are off) has the less impact on reaching comfort temperature. The ranking of parameters and their interactions has been discussed through the paper. [ABSTRACT FROM AUTHOR]

Numerous studies are exploring methodologies to enhance flame resistance and minimize the emission of toxic gases and chemicals from building materials in the event of a fire, aiming to mitigate risks and save lives. To that end, this study produced an insulation material using stabilized fiber based on polyacrylonitrile (PAN). Stabilized fiber provides flame retardancy by forming aromatic bonds in existing PAN fiber through heat treatment. To manufacture an insulation material with fiber, a separate adhesive is needed to maintain the shape, and cellulose was selected as the adhesive. Cellulose is an environmentally friendly material that can be obtained from natural sources and has the additional advantages of excellent stability and heat resistance. For this study, PAN-based stabilizing fiber (PSF) insulation was prepared and further processed using cellulose adhesive (PSF-C). Combustion experiments and gas analysis were performed to assess the combustion risks of the developed PSF insulation, and the contents of the hazardous gases and smoke generated were measured. The hazardous gases and smoke released during combustion were considerably reduced, and the heat resistance of the insulation was improved. Furthermore, the pyrolysis reaction and thermal stability were investigated. The results demonstrated a substantial reduction in the combustion hazards associated with the PSF when cellulose was used, i.e., PSF-C was used. The findings of this study are expected to substantially contribute to advancing the practical applicability of PSF-C insulating materials and the development of safe building and fire prevention systems. We developed PAN-based stabilized fiber insulation to enhance fire safety and minimize human casualties. We utilized an eco-friendly cellulose adhesive for structural integrity and studied its fire-safety properties, including HCN emissions. The developed insulation with cellulose adhesive (PSF-C) significantly reduced HCN emissions compared with a PAN insulator alone (PSF). PSF-C reduces human casualties [ABSTRACT FROM AUTHOR]

In recent years, there has been a paradigm shift in the building sector towards more sustainable, resource efficient, and renewable materials. Bio-based insulation derived from renewable resources, such as plant or animal fibres, is one promising group of such materials. Compared to mineral wool and polystyrene-based insulation materials, these bio-based insulation materials generally have a slightly higher thermal conductivity, and they are significantly more hygroscopic, two factors that need to be considered when using these bio-based insulation materials. This study assesses the hygrothermal properties of three bio-based insulation materials: eelgrass, grass, and wood fibre. All three have the potential to be locally sourced in Sweden. Mineral wool (stone wool) was used as a reference material. Hygrothermal material properties were measured with dynamic vapour sorption (DVS), transient plane source (TPS), and sorption calorimetry. Moisture buffering of the insulation materials was assessed, and their thermal insulation capacity was tested on a building component level in a hot box that exposed the materials to a steady-state climate, simulating in-use conditions in, e.g., an external wall. The tested bio-based insulation materials have significantly different sorption properties to stone wool and have higher thermal conductivity than what the manufacturers declared. The hot-box experiments showed that the insulating capacity of the bio-based insulators cannot be reliably calculated from the measured thermal conductivity alone. The results of this study could be used as input data for numerical simulations and analyses of the thermal and hygroscopic behaviour of these bio-based insulation materials. [ABSTRACT FROM AUTHOR]

Exposure to radon gas in households presents serious health risks, including an increased likelihood of lung cancer. Following the COVID-19 pandemic, the change in individual habits has led to more time spent in indoor environments with remote activities; thus, the need to raise the awareness of air quality in dwellings and to mitigate the exposure of inhabitants to radon has emerged. This study investigated radon gas concentrations in the air of Latvian dwellings. RadTrack2 passive detectors were deployed in a representative sample of households across 106 municipalities of Latvia (98% of the territory), yielding data from 487 households (973 detectors). The data revealed a median radon concentration of 52 Bq/m3 (Q1 and Q3 were 29 and 93 Bq/m3), with the majority of samples (95.6%) falling below the national reference limit of 200 Bq/m3. The building type and presence of a cellar significantly impacted radon levels, with structures lacking cellars and older buildings exhibiting higher concentrations. Mechanical ventilation proved to be more effective in reducing radon levels, compared to natural ventilation. These findings emphasize the necessity of proactive measures to mitigate indoor radon exposure and to ensure the well-being of occupants. Additionally, the dissemination of research data on radon exposure through open-access scientific publications is vital for raising awareness and implementing effective mitigation strategies. [ABSTRACT FROM AUTHOR]

The consumption of poly(ethylene terephthalate) (PET) has experienced a surge in recent times, owing to the widespread use of single-use plastic bottles, particularly in the context of beverages and drinking water. PET, a thermoplastic polymer, is known for its recyclability, and the recycled variant is referred to as rPET. The incorporation of rPET in fiber manufacturing is favored due to its cost-effectiveness, and the functionalized rPET fibers present an innovative product that can be used in a variety of applications. This study aimed to functionalize rPET fibers using the spun-bond technique, imparting antibacterial and flame-retardant properties, which are commonly employed in thermal insulator products. Nano zinc oxide (nano-ZnO) was used to confer antibacterial functionality, while phosphorus flame retardant (PFR) was used to impart flame-retardant properties. The core-sheath bicomponent fiber structure was employed to achieve the desired outcomes. The extrusion process was used to incorporate PFR and ZnO as the core and sheath components, respectively, at various ratios. The presence of nano-ZnO on the fiber shell was confirmed by the EDX data. The flame retardant study was utilized to observe the level of burning damage. The findings of the study demonstrated that increasing the percentage of PFR (maximum 8%) resulted in a significant decrease in the damage distance of the nonwoven material, with reductions of up to 60% was observed. Furthermore, the results of the antibacterial test indicated that the inclusion of an additional 3 wt% of ZnO resulted in a considerable reduction of the bacteria S. aureus and K. pneumoniae by about 99.96 and 98.79%, respectively. Based on the results obtained, it was determined that the most effective functionalized fiber was synthesized by including 3 wt% of ZnO and 5 wt% of PFR. Moreover, the incorporation of varying proportions of additives resulted in modifications to the mechanical and thermal characteristics of the fibers. This work highlights the potential of functionalized rPET bicomponent fibers as viable candidates for thermal insulator products. The utilization of functionalized rPET bicomponent fibers as a sustainable alternative for thermal insulator products showcases the commitment to environmentally friendly solutions, contributing to the overall goal of sustainability in the manufacturing industry. [ABSTRACT FROM AUTHOR]

Plasma sprayed thermal barrier coatings (TBCs), applied in internal combustion engines, can have a profound impact on the apparent rate of heat release. Upon fuel jet contact with the piston wall, the heat loss seems to increase compared to an uncoated piston and combustion appears delayed. Permeable porosity of plasma sprayed TBCs is identified as one of the possible causes for this unwanted effect. In this article the impact of open porosity and sealing of the TBC surface are investigated with single cylinder engine experiments and with simulations. Based on the results, a mechanism is presented to explain the observations. [ABSTRACT FROM AUTHOR]

Thermal balance is paramount to human comfort and safety. To better understand the effects of the material and environment, a modified sweating-hot-plate test was used to incorporate environmental parameters such as the ventilation and microclimate thickness. It was found that at wind speeds ≤ 0.5 m/s, the environment has the most significant effect on the insulation. However, at an increased wind speed (1.3 m/s), the construction of the material has a large influence on the insulation of the system. At a low metabolic rate, the heat storage can be compensated for through dry heat loss; but, at a higher metabolic rate, substantial differences in the sweating rates are required based on the material and environment. The various aspects of the environment wind speed, microclimate thickness, and ventilation are crucial, but, in certain combinations, the material can have a significant impact as well. [ABSTRACT FROM AUTHOR]

One of the most important factors in the LPDC process is the heat transfer during the solidification of the molten alloys, which is responsible for the resulting microstructure and, thus, the quality of the cast piece. The use of foundry coatings has been lately suggested as a proper strategy to control the heat transfer while protecting bonded moulds from aluminium adhesion by providing a barrier between the surface and the liquid metal. LPDC die coating failures usually come from the loss of adherence or excessive wear originated in the successive filling processes, which requires stopping production for the reapplication of the coating. In the present work, coatings with different insulation capabilities have been evaluated, in terms of adherence and wear tests, in order to select the most promising alternative for LPDC die coating. This study confirmed that surface preparation and cleanliness are vital for an adequate adhesion of the coatings to ensure their durability. The results evinced that the use of a primer layer provided a higher adhesion of the coatings and considerably improved their perfomance. The coating that presented the best results in terms of adhesion and wear resistance under different abrasive testing conditions was coating B3. [ABSTRACT FROM AUTHOR]

The rapid development of new energy automobile industry has put forward higher requirements for the temperature resistance of insulating enameled wire of automobile motor. The preparation of high-performance and low-cost enameled wire coating has become a research hotspot in this field. In this paper, the one-step solvent-thermal method was used to prepare pentagonal star-like ZrO2 particles. In situ polymerization method was used to prepare a PI/ pentagonal star-like ZrO2 composite film with high performance and low cost. The results showed that the prepared pentagonal star-like ZrO2 particles were uniformly distributed, which improved the dispersion of ZrO2 in PI polymer. Compared with pure PI films, the hydrophobic properties and tensile stress of PI/ pentagonal star-like ZrO2 composite films are improved by 4. 8 times after adding 3% of ZrO2 nanoparticles. The initial thermal decomposition temperature was increased by 8.30%. The dielectric constant is increased by 3. 2 times. It can be seen that the five-pointed star ZrO2 has significantly improved the insulation and high temperature resistance of pure PI film. This work has important guiding significance for developing new formula of high performance enameled wire. [ABSTRACT FROM AUTHOR]

Following the invasion of Ukraine and the associated energy policy tensions with Russia, the EU began looking at how it could replace Russian energy sources. One of the proposed solutions is to decrease energy consumption. Buildings have been the principal target, owing to their high energy usage – especially of natural gas, which the EU is particularly keen on reducing. This literature review article summarises existing knowledge on the potential energy savings that can be made through energy efficiency improvements to existing buildings in Central and Eastern Europe. The countries in this region share common traits due to their Communist past and associated legacy of poor energy efficiency, both generally and in buildings in particular. At the same time, Central and Eastern Europe contains a range of geographical and climatic regions, and so, the findings of this paper are applicable to other regions. This bibliometric analysis identifies three main areas (insulation, heating source and policy) in which the academic literature has identified potential for energy efficiency improvements to buildings. On the basis of these findings, this paper looks at the policy implications for reducing energy consumption in buildings and thus helps the EU to become less dependent on energy supplies from Russia. [ABSTRACT FROM AUTHOR]

Cross-Laminated Timber (CLT) panels have many structural benefits but do not have much thermal resistance. We have developed a solution to insulate CLT structures that uses high-performance insulation panels that provide R-values up to R40/inch. The CLT panels are made of layers of wood laminates (three, five, seven or more). The solution replaces some of the wood laminates in the CLT production with the insulation panels in a staggered fashion so that the wood laminates maintain contact throughout the panel, ensuring the CLT panel's structural integrity. The insulated CLT panels have factory-installed water-resistive barriers reducing the installation time by eliminating installing insulation and water-resistive barriers on site. Per simulations, the CLT/insulation panel achieved code-required insulation levels with commonly available insulation materials. The significance of the thermal mass of CLT/insulation hybrid building envelopes was quantified by comparing the whole building energy performance and peak demand of traditional low mass and CLT wall assemblies resulting in up to 7% reduction in peak demand for cooling in Knoxville, TN, in a multifamily building. Buildings contribute over 40 percent of carbon emissions. The proposed CLT/insulation hybrid building envelope addresses both operational and embodied carbon by having high thermal resistances due to the embedded insulation sections and eliminating the use of high embodied carbon materials such as steel and concrete. The carbon benefit is estimated. [ABSTRACT FROM AUTHOR]

This paper attempts to ascertain the thermal and acoustic impacts of introducing a vegetative roof layer on insulated and uninsulated metal roofs for tropical climates, through field measurements in Skudai, Johor, Malaysia, that were conducted for both dry and wet days. Four small-scale roof modules were tested, namely an uninsulated metal roof (uiMDR), an insulated metal roof (iMDR), and two identical corresponding modules with an additional vegetative component (uiGR and iGR, respectively). Outdoor ambient temperature (Tamb) was the most influential correlated variable affecting the roof outer surface temperature (RTOS) in 50% of the assessed scenarios. On the selected dry day, the inter-quartile ranges (IQR) of iGR, iMDR, uiGR, and uiMDR were 6.21 °C, 8.32 °C, 6.69 °C, and 1.66 °C, respectively; the IQRs were 1.6 °C, 4.11 °C, 2.59 °C, and 1.78 °C, respectively, on the selected wet day. Based on design U-value calculations, iGR was better than iMDR and uiMDR for both dry and wet days. The U-value of uiGR was also better than iMDR under dry-day conditions. The Wilcoxon signed-rank test also indicated a statistically significant difference in the roof inner surface temperature (RTIS) measurements (p-value = 0.00) during Malaysian daylight hours, between 8.00 a.m. and 6.00 p.m., regardless of the weather. In terms of sound level reduction under dry-day conditions, the Kruskal–Wallis and Wilcoxon signed-rank tests showed statistically significant differences in sound level reductions, with iGR and uiGR performing better than iMDR and uiMDR (p-values = 0.00). The sound level reductions for iGR, iMDR, and uiGR were 51%, 32%, and 31%, respectively, while uiMDR experienced sound level amplifications by 6%, possibly due to the acoustic resonance effect. This proof of concept may encourage a broader application of extensive GRs in Malaysia using metal roofs, beyond the conventional RC base construction method. [ABSTRACT FROM AUTHOR]

The paper is devoted to an overview of the development of insulating materials and media used in high-voltage equipment over the past 150 years. The transition from traditional dielectrics such as air, porcelain, and glass to modern developments based on polymers and polymeric composites is considered. The increase in the use of synthetic liquids such as silicone and specialty oils is discussed, and the emergence of alternatives, such as liquid nitrogen for technological applications of superconductivity, is considered. Special attention is paid to the use of different gases, for example, fluoronitriles and ketones at different pressure values as an alternative to air and gas for gas insulation of high-voltage equipment. [ABSTRACT FROM AUTHOR]

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Vortex generators are very effective tools in increasing heat transfer from one region to another, especially by convection, and appear to be a very promising concept to be coupled with heat recovery systems. On the other hand, Thermoelectric Generators (TEGs) are devices able to convert differences in temperature into electrical power using the Seebeck effect, the main advantage being working on high or even low differences in temperature. These TEG modules could be very effective tools in the hybridization of heat recovery systems. In this context, the present paper suggests an innovative system that couples three important energy axes together such as Heat recovery, TEGs, and Vortex generators. The current study employs a TEG in a rectangular channel to analyze the influence of the TEG on the flow and the effect of the effect of flow regime on producing electric power in order to assess the viability of this recently proposed concept. The investigation is conducted by varying the Reynolds number in a range of five values: 1000, 2000, 4000, 7000, and 10,000, applying six different configurations. Consequently, the results show that several factors affect the electrical power generated by TEG such as the emplacement, angle of attack, and absence/presence of vortex generators. On the other side, the heat recovered by the flow is affected by the TEG and Re, where the highest heat recovery is achieved at Re = 10,000 for configuration 4 with electrical power of 7.4 W, and for configuration 5 heat recovered by the flow of 1913 W. Besides, it was concluded that TEGs decreased the losses in both hot and cold sides by 1.42 times.

The uncontrollable rise in energy consumption become a most significant issue in recent decades. One of the largest consumers of energy resources across all industries is the residential building sector. Researchers have suggested several strategies to reduce energy loss, including enclosing insulation in wall structures because air conditioning systems account for the majority of energy use inside homes. The main goal of this article is to increase residents' thermal comfort (Tc) while reducing their heating load (HL) and cooling load (CL). Using the EnergyPlus program, the building model was simulated in sample cities with various climatic conditions. For optimization, the first seven design variables were determined in Jeplus software and then multi-objective optimization was performed by the Non-dominated Sorting Genetic Algorithm (NSGA-Ⅱ) algorithm. As a result, Tc, HL, and CL values improved by 38–62, 61 to 100, and 17 to 39 percent, respectively.