Search

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. Highlights: 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]

Wind power-to-gas concepts have a high potential to sustainably cover the increasing demand for hydrogen as an energy carrier and raw material, as it has been shown in the past that there is an enormous potential in energy overproduction, which currently remains unused due to the shutdown of wind turbines. Thus, there is barely experience in maritime production, offshore storage, and transport of large quantities of liquid hydrogen (LH2) due to the developing market. Instead, tank designs refer to heavy standard onshore storage and transport applications with vacuum insulated double wall hulls made from austenitic stainless steel and comparatively high thermal diffusivity and conductivity. This reduces cost effectiveness due to inevitable boil-off and disregards some other requirements such as mechanical and cyclic strength and high corrosion resistance. Hence, new concepts for LH2 tanks are required for addressing these issues. Two innovative technical concepts from space travel and high-temperature applications were adopted, combined and qualified for use in the wind-power-to-gas scenario. The focus was particularly on the high requirements for transport weight, insulation and cryogenic durability. The first concept part consisted of the implementation of FRP (fiber-reinforced plastics)–steel hybrid tanks which have a high potential as a hull for LH2 tanks. However, these hybrid tanks are currently only used in the space sector. Questions still arise regarding interactions with coatings, production, material, temperature resilience and design for commercial use. Thermally sprayed thermal barrier coatings (TBC) in turn show promising potential for surfaces subject to high thermal and mechanical stress. However, the application is currently limited to use at high temperatures and needed to be extended to the cryogenic temperature range. The research on this second part of the concept thus focused on the validation of standard MCrAlY alloys and innovative (partially) amorphous metal coatings with regard to mechanical-technological and insulating properties in the low temperature range. This article gives an overview regarding the achieved results including manufacturing and measurements on a small tank demonstrator. [ABSTRACT FROM AUTHOR]

The largest influences on a building's cooling and heating load come from heat absorption and loss through building surfaces. Most of the heat gain is absorbed by a structure's roof. Applying insulation to building envelopes is an efficient approach to cut back on heating and cooling energy use as well as the damaging effects of the construction industry on the environment. As a result, it is extremely important to choose the right insulation material and determine the ideal insulation thickness. Eight diverse cities with a range of climatic variables that are spread over several Indian areas (geometric coordinates) are the starting point for this investigation. To overcome the constraints of the various climate typology representing the diverse climatic circumstances present in India, a generic method is proposed, considering the numerous climatic parameters for eight selected Indian locations. The subject of the project is the analysis of a composite insulation layer made from a combination of chosen seven insulating materials, each of which has a unique property. This building roof envelope is examined using ANSYS software and e-Quest building energy modeling. The results of simulations over the course of the whole year show a significant decrease in energy use and CO2 emissions. By altering the thickness of the created envelope, the annual energy need is decreased for each of the seven trials in the range of 30–90%. A decrease in heat flow results in sustainable buildings and a low-carbon future by lowering temperatures by 19 degrees and cutting greenhouse gas emissions by 90% to 96%. [ABSTRACT FROM AUTHOR]

Purpose: The use of thermal insulations reduces the risk of hypothermia, therefore decreases the risk of death in trauma victims. The aim of the study was to assess whether thermal insulations cause artifacts, which may hinder the diagnosis of injuries, and how the used thermo-systems alter the radiation dose in polytrauma computed tomography. Methods: Computed tomography scans were made using the road accident victim body wrapped consecutively with 7 different covers. 14 injury areas were listed and evaluated by 22 radiologists. The radiation dose was measured using a dosimeter placed on the victim in the abdominal area. Results: No significant artifacts in any of the tested covers were observed. The presence of few minor artifacts did not hinder the assessment of injuries. Certain materials increased (up to 19,1%) and some decreased (up to -30,3%) the absorbed radiation dose. Conclusions: Thermal insulation systems tested in this study do not cause significant artifacts hindering assessment of injuries in CT scans. Concern for artifacts and increased radiation dose should not be a reason to remove patients' thermal insulation during performing trauma CT-scanning. [ABSTRACT FROM AUTHOR]

This research aims to reduce electricity use and promote activities to reduce electricity use within the organisation through a case study from the PCB assembly department. It was found that the total annual electricity consumption is approximately 2,099,093 kWh/y. The amount of PCB production per time is 7 sheets, and the delay time to release PCB sheets is 15 s per sheet. Therefore, the researcher used the AHP techniques to identify the problems. The solution is to introduce innovative insulation wrapping that can help reduce heat radiation from the machine. From the experiment, it was found that after the improvement, the production number increased to 11 sheets, with a delay time of 10 s per sheet. Production increased by 33.3%, heat loss decreased by 53.5%. As a percentage per power dropped 51% and the percentage of the electricity cost was 70.1% the payback period was 1.69 years. [ABSTRACT FROM AUTHOR]

This paper seeks to assist in the surveying of listed properties and the considerations that may be taken when addressing whether to insulate solid flooring and, if so, how to go about it. The author seeks to address a variety of potential problems and opportunities that may be found when assessing the property and does not consider this paper to cover all eventualities. One of the main things the author is aware of is the merit of each property needing to be assessed as a unique and individual entity. In many cases, it may also be worth looking at areas within the property itself; different rooms will have different needs, uses and potentially differing existing flooring and will therefore need to be addressed on a room-by-room basis. As the author runs a company that specialises in limecrete flooring, she is aware of her own potential bias and the weighted information that she will provide in her own specialist field. Therefore, this paper does not aim to suggest a single answer approach to the question of insulating solid floors in listed buildings; however, more detail will be given with regard to an insulated limecrete flooring approach. The author does not hold any design liability, and any design ideas described in this paper are based upon her knowledge and experience in the field. In particular, when it comes to limecrete floor design, she is drawing on designs that her company has been given by their customers to work on and the opportunities this has given for consideration in this paper. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Herein, the cellulose aerogel (CellA) material was synthesized from bulk cellulose derived from corn stalks with poly(vinyl alcohol) (PVA) as the binding agent. In detail, the influence of precursor mass ratio on the physicochemical properties and adsorption capacity of CellA was thoroughly investigated, which illustrated the cellulose:PVA ratio of 15:1 as the suitable fabrication of cellulose aerogel, with favorable density, porosity, and characteristic behaviors. The surface modification for the prepared CellA was also carried out using stearic acid and polydimethylsiloxane, followed by a carbonization treatment. The obtained results revealed that the 500 °C-carbonization of the stearic acid-coated sample exhibited superior adsorption capacity of cooking oil (32.98 g/g) as well as a high hydrophobicity with a wetting angle of 131.7°. Besides, the sample also provided a relatively low thermal conductivity at 0.067–0.069 W/m K within a surveyed temperature range of 40–50 °C. Conclusively, the environmentally-inspired CellA material highlights an effective utilization of corn stalks—an abundant biomass source via a facile preparation effort as an alternative candidate for the adsorption of non-polar organic compounds and thermal insulation. [ABSTRACT FROM AUTHOR]

Biobased foams have the potential to serve as eco-friendly alternatives to petroleum-based foams, provided they achieve comparable thermomechanical and physical properties. We propose a facile approach to fabricate eco-friendly cellulose nanofibril (CNF)-reinforced thermomechanical pulp (TMP) fiber-based foams via an oven-drying process with thermal conductivity as low as 0.036 W/(m·K) at a 34.4 kg/m3 density. Acrodur®, iron chloride (FeCl3), and cationic polyacrylamide (CPAM) were used to improve the foam properties. Acrodur® did not have any significant effect on the foamability and density of the foams. Mechanical, thermal, cushioning, and water absorption properties of the foams were dependent on the density and interactions of the additives with the fibers. Due to their high density, foams with CPAM and FeCl3 at a 1% additive dosage had significantly higher compressive properties at the expense of slightly higher thermal conductivity. There was slight increase in compressive properties with the addition of Acrodur®. All additives improved the water stability of the foams, rendering them stable even after 24 h of water absorption. [ABSTRACT FROM AUTHOR]

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]

Local buckling (wrinkling) is very common in metal-faced insulating sandwich panels (MFISPs) due to the small thickness of their face sheets. In some cases, wrinkling leads to sudden failures, while in others it leads to degradation of the overall stiffness and can decrease the failure load. A simplified finite-element modelling approach is presented to estimate the local buckling pressure of such panels. In the proposed approach, only the face sheet under compression is modelled, thus avoiding the need to perform a full three-dimensional (3D) structural analysis. The working assumption is that the relative deflection of the buckled face against the face under tension (unbuckled face) can be modelled using a two-parameter elastic foundation approach. The elastic foundation is simulated by closely spaced horizontal and vertical springs that model the rigidities of the foam core. Two models are used to determine the elastic foundation properties. The simplified approach was validated through comparisons with 3D analyses of full sandwich panels and available experimental results. It was found that the proposed approach can be applied to various types of MFISPs (flat or heavily profiled) with a variety of foam cores and face sheet thicknesses. [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]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Large amounts of seaweed are deposited on shores worldwide daily. The presence of this natural pollutant on the coast is not only considered an environmental burden but also often hinders the development of tourism in the affected areas. Depending on the beach surface area, local governments worldwide spend considerable portions of their budgets to remove seaweed from beaches. Moreover, the removed seaweed occupies increasing space in landfills where it is disposed. Seaweed is noncombustible and decomposes slowly over long periods. In this study, we consider the use of seaweed (a natural waste) as a value-added product for insulation and building materials. Seaweed (Posidonia Oceanica) boards with dimensions of 250 mm × 60 mm × 10 mm were obtained by pressing a mixture of processed seaweed and an organic binder. The as-prepared boards were analyzed for their physical–mechanical properties according to the British standards. The boards with a mean humidity level of 9.15% and density of 0.4045 g·cm−3 demonstrated a maximum bending resistance of 2.720 × 103 N·m−2 and mean expansion upon water adsorption of ∼10% with regards to length and width and ∼30% with regards to height. The tested samples showed significant humidity resistance according to the boiling test and an average thermal conductivity of 0.047 W·m−1·K−1, which is comparable to that of polystyrene. Computational analysis of the “seaweed material” model revealed significant thermal and mechanical properties. The mechanical strength of the computed material, including its high Young’s and shear moduli, renders it a promising candidate in construction.

Abstract 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.

RELEVANCE. The current technical condition of electrical networks at the moment is generally unsatisfactory with an average level of physical wear of about 60-70 %, therefore,the development of fundamentally new methods for assessing their technical condition is currently an urgent task. The methods of assessing the technical condition of electrical networks analyzed in the article are based to a greater extent on the subjective and insufficiently accurate method of expert assessments, which actually does not take into account the data of its technical diagnostics, as well as statistics of defects and failures. OBJECT. To develop a methodology for assessing the technical condition of electrical networks, which would be based on probabilistic models characterizing the physical processes occurring in electrical networks, as well as data from their technical diagnostics, statistics of defects and failures. METHODS. To assess the technical condition of electrical networks, a probabilistic assessment method was used. In this case, the methodology involves sequential determination of the probabilities of occurrence of selected groups of emergency modes, the probability of failure of a network element as a whole, as well as the probability of failure of an object and a group of objects of the power grid. RESULTS. Based on the research results, probabilistic models of failure of electrical networks were obtained, which, unlike the assessment methods discussed in the article, are based on data from technical diagnostics and inspections of electrical equipment. An example of the implementation of the developed methodology on real electrical network objects is given. CONCLUSION. The developed methodology allows for a more reasonable prioritization of technical impacts on electrical grid equipment, which will make it possible to replace or repair equipment that has actually exhausted its physical resource, which will reduce the frequency of emergency conditions and reduce damage from power supply interruptions.

Abstract 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 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.

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.

The widespread use of cellulose nanofiber (CNF)-based aerogels is hindered by their limited flame retardancy and mechanical properties. This study addresses these challenges by developing cellulose nanofiber/sodium alginate/fly ash (CNF/SA/FA) aerogel through a one-pot method, utilizing industrial waste fly ash (FA) as a reinforcing material. Various characterization and analytical techniques were employed to evaluate the properties of the CNF/SA/FA aerogel. The findings have revealed that resulting aerogel exhibited excellent thermal insulation performance, with a thermal conductivity of 0.485 W/(m·K), along with an impressive compressive strength of 88.4 kPa and favorable shape processability. Vertical combustion tests demonstrated a V-0 rating, indicating superior flame retardancy, and the aerogel achieved a remarkable 79.16% residual carbon, confirming their effective heat shielding capabilities. Notably, the incorporation of FA significantly enhanced both the thermal and mechanical properties of the composite aerogel, presenting a sustainable and effective solution to optimizing the properties of aerogel for thermal insulation.

Replacing thermoset insulation by healable and recyclable covalent adaptable networks is a promising approach to the sustainable development of electrical and electronic devices. However, the repair performance gifted by dynamic covalent bonds always conflicts with the excellent mechanical properties gifted by stiff cross‐linked networks. In this paper, by introducing dynamic thiocarbamate bonds, polythiourethane (PTU) with excellent mechanical properties and electrical insulation comparable to commercial epoxy resins are successfully developed, which exhibit superior healability and recyclability properties. Sub‐centimeter scale electrical breakdown failures of the PTU samples could be efficiently self‐healed with a healing efficiency up to 90%, while the storage modulus and volume resistivity exceeded 2 GPa and 1016 Ω cm, respectively. Even though the electrical breakdown strength inevitably declined after multiple repair processes, PTU samples could restore their initial excellent insulation performance by simply reprocessing with the efficiency above 95%. Moreover, the efficient healability performance of large‐sized electrical breakdown failures remained after the reprocessing. These outstanding characteristics underscore the tremendous potential of PTU materials as a new generation of sustainable high voltage insulation. [ABSTRACT FROM AUTHOR]

RELEVANCE. The length and complexity of the geography of medium voltage cable lines is at a high level. Such lines extend underground, on supports in the air. In order to constantly maintain the reliability of city power supply at a high level, any interruptions and accidents should be promptly corrected.TARGET. The main goal of the work is to develop the theory of medium voltage CL research, to practically and theoretically substantiate the search for the most convenient and effective installation for CL diagnostics, to study and develop possible modifications of CL diagnostic installations.METHODS. A variant of CL diagnostics based on the CPDA-60 installation is proposed, which makes it possible to find and localize the places where defects occur in the insulation based on the measurement and analysis of partial discharges (PD). Suitable for insulation monitoring in all types of high voltage cables. The CPDA installation can be used when testing new cable lines being put into operation, and to analyze the condition of old cables in operation.RESULTS. Cable lines require an integrated approach to diagnostics and monitoring, since the reliability of modern authentication systems for the generation and distribution of electricity is largely determined by the electrical reliability of electrical equipment. Technical diagnostics of equipment is a key link, the quality of which determines the efficiency of the processes of organizing production activities, strategic planning and renovation of electric grid assets.CONCLUSION. The study and analysis of the presented data and research allows us to form a conclusion regarding the method of measuring and localizing partial discharges (PD) in power cable lines (CL) using the Online Wire Testing System (OWTS) diagnostic system. The OWTS system allows real-time measurements without interrupting cable lines, making it especially valuable to the energy industry. Thanks to the introduction of advanced technologies and signal processing algorithms, the method has high accuracy and sensitivity to minimal manifestations of private discharges, which allows not only to detect, but also to accurately localize the location of defects in the insulation. The use of this method can significantly increase the service life of power cables, reduce the likelihood of sudden accidents and, as a result, reduce the cost of repair and maintenance of electrical power equipment. Ultimately, improvements in diagnostic and monitoring techniques, including the method of measuring and localizing PD in power lines using OWTS, represent a significant step towards improving the reliability and safety of electrical power systems. This will not only reduce operating costs, but also ensure uninterrupted and high-quality power supply to consumers.

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.

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]

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]

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]

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]

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]

This research aims to reduce electricity use and promote activities to reduce electricity use within the organisation through a case study from the PCB assembly department. It was found that the total annual electricity consumption is approximately 2,099,093 kWh/y. The amount of PCB production per time is 7 sheets, and the delay time to release PCB sheets is 15 s per sheet. Therefore, the researcher used the AHP techniques to identify the problems. The solution is to introduce innovative insulation wrapping that can help reduce heat radiation from the machine. From the experiment, it was found that after the improvement, the production number increased to 11 sheets, with a delay time of 10 s per sheet. Production increased by 33.3%, heat loss decreased by 53.5%. As a percentage per power dropped 51% and the percentage of the electricity cost was 70.1% the payback period was 1.69 years.

Wind power-to-gas concepts have a high potential to sustainably cover the increasing demand for hydrogen as an energy carrier and raw material, as it has been shown in the past that there is an enormous potential in energy overproduction, which currently remains unused due to the shutdown of wind turbines. Thus, there is barely experience in maritime production, offshore storage, and transport of large quantities of liquid hydrogen (LH2) due to the developing market. Instead, tank designs refer to heavy standard onshore storage and transport applications with vacuum insulated double wall hulls made from austenitic stainless steel and comparatively high thermal diffusivity and conductivity. This reduces cost effectiveness due to inevitable boil-off and disregards some other requirements such as mechanical and cyclic strength and high corrosion resistance. Hence, new concepts for LH2 tanks are required for addressing these issues. Two innovative technical concepts from space travel and high-temperature applications were adopted, combined and qualified for use in the wind-power-to-gas scenario. The focus was particularly on the high requirements for transport weight, insulation and cryogenic durability. The first concept part consisted of the implementation of FRP (fiber-reinforced plastics)–steel hybrid tanks which have a high potential as a hull for LH2 tanks. However, these hybrid tanks are currently only used in the space sector. Questions still arise regarding interactions with coatings, production, material, temperature resilience and design for commercial use. Thermally sprayed thermal barrier coatings (TBC) in turn show promising potential for surfaces subject to high thermal and mechanical stress. However, the application is currently limited to use at high temperatures and needed to be extended to the cryogenic temperature range. The research on this second part of the concept thus focused on the validation of standard MCrAlY alloys and innovative (partially) amorphous metal coatings with regard to mechanical-technological and insulating properties in the low temperature range. This article gives an overview regarding the achieved results including manufacturing and measurements on a small tank demonstrator.

This study investigates the high-value recycling of stone wool from construction and demolition waste into alkali-activated lightweight insulation aggregates, designed for ground cover insulation. Various proportions of milled and as-is stone wools are alkali-activated to produce aggregates. The aggregates demonstrate loose bulk densities ranging from 720 to 850 kg m−3 and dry thermal conductivity from 0.075 to 0.094 W m−1·K−1, with moderate water sorption capacities. The fibre morphology of as-is stone wool influences rheology, introducing a greater number of pores or defects, which results in a decrease in mechanical strength. Hydrothermal simulations reveal that the floor assembly of the rehabilitated crawl space, partially filled with the fabricated aggregates, shows a reduction in water content and an increase in floor surface temperature. This observation suggests potential benefits for maintaining the structural integrity of buildings and enhancing occupant comfort.