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Electric machines form an essential part of a wide range of modern systems. When speed control is required, the use of pulse width modulation‐based inverters is generally the solution of choice. It is also usual to connect the machine to the inverter using a cable. The combination of these three elements produces the potential for voltages which exceed the dc link voltage to occur at the machine terminals. Methods for predicting the terminal voltage exist; however, these methods assume that the pulses applied to the system can be considered as isolated, discrete events. The authors highlight an issue with this assumption. When a switching event occurs, it will cause a voltage disturbance in the unswitched phases of the system due to the mutual coupling between the phases. If a second switching event occurs within a short time of this event the resultant voltage will interact with the previous switching event resulting in a higher terminal voltage than would be the case for an isolated event. This effect can be problematic for insulation design if it is not considered. This issue is demonstrated, with the worst‐case scenarios identified and potential methods of reducing terminal voltage being proposed. [ABSTRACT FROM AUTHOR]

In this paper, the thermal insulation performance of silica aerogel was studied. Aerogel heat insulation blankets can be widely used in the military, cold storage, aerospace, automotive and other industries. The heat insulation principle of aerogel was analyzed theoretically, and the heat transfer model of aerogel was established. Experiments are designed to verify the accuracy of the model, and it is concluded that the distance between the aerogel and the target is more important for the thermal insulation effect than the thickness of the aerogel. [ABSTRACT FROM AUTHOR]

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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]

Electric power provision for all the customers is not always possible for distribution companies. Some customers are interested in serving their load through renewable resources regarding the climate situation. Electrically off‐grid zero‐energy building is an applicable concept, in which the electrical energy provision of the buildings is isolated from the power supply infrastructures. This paper introduces a robust bi‐level programming model to create a cost‐effective off‐grid zero energy complex in Kish Island under risk management. The upper level of the planning is composed of two components, the passive design of buildings within the complex and the design of a stand‐alone energy system. The passive design as an energy‐saving tool includes the selection of insulation material for building external walls and finding the optimum thickness. Also, the stand‐alone energy system design denotes the sizing of diesel generator, photovoltaic, and battery energy storage as the distributed energy resources. The lower‐level problem optimally handles the annual scheduling of these resources to meet the complex demand under the impact of passive cooling. The Karush–Kuhn–Tucker condition method is used to solve this bi‐level planning problem. Furthermore, the battery degradation is concerned via the throughput model to consider the replacement cost of the problem. [ABSTRACT FROM AUTHOR]

Enhancing the energy efficiency and climate resilience of existing buildings is crucial amid growing environmental challenges. While extensive research has focused on non-residential buildings, studies on thermo-hygrometric conditions in warehouse-type buildings, particularly in subtropical climates, remain limited. This study investigated the impact of building envelope deficiencies on indoor thermal and moisture regulation at the Nori Distribution Center. Using infrared thermal imaging and long-term environmental monitoring, significant thermo-hygrometric fluctuations were identified, primarily due to design and construction deficiencies. Poor insulation, inadequate sealing, and the lack of moisture barriers contributed to unstable indoor temperature and humidity. Seasonal analysis showed that during summer, the median second-floor air temperature reached 28.8 °C, peaking at 39.2 °C, with relative humidity exceeding 70% for 45% of the time. First-floor relative humidity surpassed 70% for 72% of the time. While condensation risk remains low year-round, it increases significantly with air infiltration through gaps in the building envelope. This study recommends enhancing the sealing of the building envelope, upgrading insulation materials and moisture barriers, particularly in the roof, and optimizing the HVAC system to improve energy efficiency and storage conditions. These findings offer valuable recommendations for retrofitting warehouse-type buildings in subtropical climates to improve energy efficiency and climate resilience. [ABSTRACT FROM AUTHOR]

In hilly regions, the average ambient temperature during summers and winters typically ranges from 297 to 307 K (24 to 34 °C) and 277 to 293 K (4 to 20 °C). Therefore, this paper aims to describe the development and evaluation of an insulated Himshakti biogas plant (plant 2) for hilly regions and its comparison with the conventional biogas plant (plant 1). In terms of gas production, plant 1 generated an average of 0.614 m3 (614.18 L), while plant 2 produced significantly more gas, i.e., 0.775 m3 (775.23 L) due to its insulation which generates more income. Henceforth, the results indicated that the biogas production rate in the insulated plant was highest (820 L or 0.82 m3) when the temperature was at 307 K (34 °C) in the month of May. The comparative economic analysis showed that the insulated plant model is the most feasible for hilly regions, covering the total expenditure in less than 3 years and giving returns within the next 22 years. The developed biogas plant is favorable for its temperature, greater life span, more income, and reduced daily expenses (in terms of LPG). [ABSTRACT FROM AUTHOR]

Polymer-based energy storage media are widely used in electrical and electronic applications due to their high power density and excellent charge and discharge efficiency. In this paper, thermoplastic polyurethane elastomer (TPU) organic fillers were doped with polyetherimide (PEI) by the solution blending method to prepare PEI composite films with excellent energy storage properties. The effects of different TPU contents on the dielectric properties, leakage current density, and energy storage performance of the composite films were explored. The results showed that the flexible TPU fillers, which could improve the inter-chain interactions and spatial structure of PEI, reduced the chain spacing of the polymer, effectively hindered the input of charge carriers, and mitigated the electric field distortion, thus improving the insulation and dielectric properties of PEI. When the mass fraction of the added TPU elastomer reaches 0.75%, the energy storage density of the composite film reaches 11.51 J/cm3, which is 2.88 J/cm3 higher than that of the pure polyetherimide, while maintaining a high charge/discharge efficiency (87.32%), and the energy storage performance has been significantly improved under an applied electric field strength of 600 MV/m. The results show that the composite film is more efficient than the pure polyetherimide, and the energy storage performance has been significantly improved. [ABSTRACT FROM AUTHOR]

Assessing the insulation condition of oil‐impregnated paper (OIP) bushings is necessary to guarantee the safe operation of power transformers. Moisture is the main threat to the insulation of OIP bushings. Therefore, accurately estimating their moisture value is crucial to keep power systems running smoothly. However, it has been suggested that the ageing status of OIP bushings should be considered while assessing the moisture. Dielectric frequency‐domain spectroscopy (FDS) has been extensively employed for assessing insulation condition of OIP insulations due to its benefits. A new approach was proposed to assess the insulation condition of OIP bushings using FDS results. Various OIP samples with various moisture levels and degrees of polymerisation (DP) were selected. The extended Debye model (EDM) parameters related to each sample were calculated using their tanδ − f curve. A time constant database (TCD) was created using the obtained time constants of EDM, which includes the dominant time constant and time constant related to the R0 – C0 branch, and their corresponding insulation condition. Then, a method was introduced based on the created TCD to estimate the insulation condition of OIP bushings. The results showed that the average relative error of moisture and DP estimation is 8.33% and 6.32%, respectively. [ABSTRACT FROM AUTHOR]

Cellulose and paper produce significant waste such as ash, activated sludge, and sludge from the pulp and paper industry. Depending on the raw material, legislation, and subprocesses, these sludges contain around 30–50% organic matter, mainly composed of less than 0.02 mm cellulose fibers and hemicellulose and lignin. This work used sludge from the pulp and paper industry as a substrate for manufacturing mycelium-based biomaterials using the white rot fungus Trametes versicolor. Chemical and surface analyses revealed the formation of new materials. Acoustic impedance analyses revealed that these materials have a noise reduction coefficient and sound absorption average comparable to extruded polystyrene and polyurethane. In addition, the material's thermal conductivity was near that of sheep wool. Therefore, the biomaterials fabricated using sludge and Trametes versicolor have the potential to be a game-changer in the industry as promising thermoacoustic insulators. [ABSTRACT FROM AUTHOR]

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]

The problem of energy shortages and changing climatic conditions has received a lot of attention in recent years. The building sector accounts for 60% of global energy consumption, with domestic buildings accounting for 20% to 40%. Most of this energy is used for heating, cooling, and ventilation. To address such energy shortages, the development of extremely energy-efficient buildings is a critical requirement for improving Pakistan's environmental status. Innovative building insulation solutions may be able to assist the country in coping with the crisis. The focus of this study was on the northern areas of Pakistan, intending to evaluate approaches for better thermal performance of buildings in cold climates. Insulation materials that are both innovative and cost-effective have the potential to minimize operational energy requirements and hence make buildings more efficient. In this study two commercially available insulating materials, polyethylene and polystyrene were assessed experimentally for a residential building in Murree, a hill station of Pakistan. The case study building was monitored using extruded polystyrene and polyethylene. Thermal data was recorded on hourly basis using a Testo Saveries System for 14 days in 2019 and for the current study 6 hourly data is used. Comparison of these two market available insulation materials in test room 1 and test room 2 are compared with the control room. The test materials were additionally compared based on their cost and minimum available thickness being applied. Polyethylene (PE) was observed to be five times cost effective than the other insulation material. In addition, the thermal performance of PE was comparatively better than extruded polystyrene (XPS), as in most of the days, the indoor temperature did not drop below 3°C, while Room with XPS had minimum 2°C and the control room showed more fluctuations in temperature from - 2°C to 2.5°C in that duration of the year. Polyethylene was also concluded to be the better material in terms of thickness necessary for optimum thermal performance and is hence suggested for use in buildings in Pakistan's colder regions. [ABSTRACT FROM AUTHOR]

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]

In this paper, we revisit the Canadian experience with floating exchange rates since 1950. Canada was a pioneer in successfully adopting a floating exchange rate during the Bretton Woods pegged exchange rate regime. Since then, most advanced countries have followed the Canadian example. A key finding of our paper based on historical narrative and econometric analysis is that economic performance under floating depended on its monetary policy performance as Milton Friedman originally argued in his seminal 1953 article making the case for floating exchange rates. Canadian monetary policy achieved low and stable inflation once it adopted inflation targeting as a nominal anchor. Also, Canada's floating exchange rate provided it with a modicum of insulation from external shocks, especially commodity price shocks that influenced both the level and volatility of the real exchange rate over the past three decades. The Canadian experience with floating (along with that of other small open economies such as Australia, New Zealand and Sweden) combined with inflation targeting became a global model for sound monetary policy. [ABSTRACT FROM AUTHOR]

Energy-efficient materials are essential in buildings to reduce energy consumption, lower greenhouse gas emissions, and enhance indoor comfort. These materials help address the increasing energy demand and environmental impact of traditional construction methods. This paper presents a comprehensive literature review that explores advanced materials and technologies for improving building energy efficiency, sustainability, and occupant comfort. The study applies a comparative analysis of peer-reviewed research to examine key technologies analyzed include building-integrated photovoltaics, advanced insulating materials, reflective and thermal coatings, glazing systems, phase-change materials, and green roofs and walls. The study highlights the significant energy savings, thermal performance, and environmental benefits of these materials. By integrating these technologies, buildings can achieve enhanced energy efficiency, reduced carbon footprints, and improved indoor comfort. The findings underscore the potential of advanced building materials in fostering sustainable construction practices. The methodology of this review involves collecting, analyzing, summarizing, comparing and synthesizing existing research to draw conclusions on the performance and efficiency of these technologies. [ABSTRACT FROM AUTHOR]

Abstract This study assesses the technical, economic, and environmental assessment of a developed improved cookstove (ICS) for domestic uses focusing on outperforming the traditional charcoal cookstove by improving technical performance, fuel economy, and environmental savings. A set of experiments were conducted to verify the performance of the ICS. The technical performance involved measuring the cooking time (tc), maximum cooking temperature (Tmax), fuel consumption (fcons), thermal efficiency (ηth), and cooling time (tcool). The economic assessment involved daily and annual fuel cost, and daily and annual fuel cost saving while environmental saving involved annual reduction of CO, CO2, NO, and NOx gases. The Tmax of the ICS reached 1273 K, reducing the tc by 18 mins, a drop of 43%. Furthermore, this reduced the fcons by approximately 50 g, around 30%. The ICS had an enhanced tcool of about 24.53 mins and attained ηth of 43.3%. In five tests, the ICS consumed about 596 g, which costs TZS 870 and TZS 317,550 per year. The reduction in consumption significantly reduces fuel costs by 29.83%. The results showed the ICS reduced the emission of CO, CO2, NO, and NOx concentrations by 258, 650, 2, and 2.5 ppm, respectively, compared to a traditional charcoal cookstove.

Thermal insulation and evaporative resistance of protective clothing are basic parameters that influence thermal stress and human performance. During training, the firefighter instructors wear an accessory (bolero) to discriminate them from the exercising personnel. Such boleros may be available at training sites in one size only. At one training site an instructor repeatedly reported pain sensation and first degree burns, while at another site problems did not occur, while similar amount of fuel in fires and comparable weather conditions were expected to lead to the same heat and radiation load. The other suspected reasons for pain and burns could be the aging effect on clothing properties, different materials in turnout gear compared to the materials in original procurement or the effect of the size of the added bolero. This limited study measured the thermal properties of the protective ensemble used by the firefighters today and focused on the case of the influence of clothing and bolero size on thermal insulation by the means of a thermal manikin. The tests complemented test series on firefighter ensembles commonly used in different incident scenarios. Additionally, a correct size and one size bigger ensemble were tested both with and without bolero. Use of bolero showed 3.6-6.7% insulation increase for size L, and no change or slight reduction for XL, indicating increasing thermal risks during exposure to heat and flames when protective layers get compressed by using wrong sizes.

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.

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.

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]

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]

The investigation into the dielectric properties of transformer oils has been a focal point in both historical and contemporary electric insulation technology as high-voltage applications have greatly benefited from the continuous research efforts in this field. The dielectric permittivity is one of the factors to be negotiated when discussing the electric insulation of any material. This work aims to showcase a new short-circuited coaxial cable method to evaluate the complex dielectric permittivity of palm, sunflower and rapeseed oil and review other previously used measurement techniques. Mainly, the test was performed using a sample holder that represents a short-ended coaxial cable filled with the test material which is connected to one port of a vector network analyser. The measurements of the input impedance for various oil samples were conducted at frequencies ranging from 1 MHz to 10 MHz. The technique uses the value of the input impedance which depends on the reflected signals from the test sample to the network analyser, consequently, the value of the dielectric permittivity and dielectric loss have been calculated using the short circuit impedance formula which involves numerical methods to get the results which shows that this method can be used as an alternative to investigate the oils insulation parameters as it provides smooth results for permittivity without any divergence, ensuring more reliable and consistent measurements as well as providing high accuracy in determining the permittivity of materials. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

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]