Lightweight Insulation Research Articles

Facile Synthesis and Properties of Highly Porous Quartz Fiber-Reinforced Phenolic Resin Composites with High Strength.

Lightweight and high-strength insulation materials have important application prospects in the aerospace, metallurgical, and nuclear industries. In this study, a highly porous silica fiber reinforced phenolic resin matrix composite was prepared by vacuum impregnation and atmospheric drying using quartz fiber needled felt as reinforcement and anhydrous ethanol as a pore-making agent. The effects of curing agent content on the structure, composition, density, and thermal conductivity of the composite were studied. The mechanical properties of the composite in the xy direction and z direction were analyzed. The results showed that this process can also produce porous phenolic resin (PR) with a density as low as 0.291 g/cm3, where spherical phenolic resin particles are interconnected to form a porous network structure with a particle size of about 5.43 μm. The fiber-reinforced porous PR had low density (0.372~0.397 g/cm3) and low thermal conductivity (0.085~0.095 W/m·K). The spherical phenolic resin particles inside the composite were well combined with the fiber at the interface and uniformly distributed in the fiber lap network. The composite possessed enhanced mechanical properties with compressive strength of 3.5-5.1 MPa in the xy direction and appeared as gradual compaction rather than destruction as the strain reached 30% in the z direction. This research provides a lightweight and high-strength insulation material with a simple preparation process and excellent performance.

Utilizing mycelium-based materials for sustainable construction

Mycelium-based materials have gained significant attention in recent years as a sustainable alternative for construction in civil engineering projects. This literature review aims to explore the utilization of mycelium-based materials for carbon dioxide (CO2) mitigation in construction practices. The review examines various studies and research articles to understand the potential of mycelium-based materials in reducing carbon emissions in the construction industry. The findings indicate that mycelium-based materials offer promising opportunities for sustainable construction, as they have the ability to sequester CO2 during their growth process. Additionally, mycelium-based materials possess desirable properties such as lightweight, fire resistance, and thermal insulation, making them suitable for structural and non-structural applications. The review also identifies the challenges and limitations associated with the implementation of mycelium-based materials in construction. Overall, this literature review provides valuable insights into the application of mycelium-based materials for carbon dioxide mitigation in civil engineering projects.

Modification Method of Expanded Polystyrene Granular Concrete Based on Computer Data Analysis

Expanded Polystyrene Granular concrete (EPS) is renowned for its exceptional lightweight and thermal insulation properties, yet it is hindered by its low strength. Despite the existence of numerous modification methods, there remains a dearth of quantification and summarization, particularly in the era of Artificial Intelligence (AI). Consequently, this study undertook the quantification of several conventional and novel modifications, uncovering intriguing challenges and discerning future trends in modification techniques. These methods encompass nanomaterials, phase change materials, ceramic concrete, and composite modifications, all aimed at bolstering mechanical properties and introducing novel functionalities to address diverse environmental, energy, and engineering requirements. Challenges encompass intricate processes, high costs, material compatibility issues, nascent processes, and application hurdles. Leveraging the advancements in simulation and AI technology, numerical simulations can meticulously replicate the microstructure of EPS granules and the physical attributes of concrete in numerical models, facilitating accurate prediction of material properties. The application of artificial intelligence techniques also includes utilizing big data analysis to optimize the proportions of various materials in EPS granular concrete, providing a valuable framework for the study of high-performance EPS granular concrete and significantly contributing to the enhancement of concrete performance.

Effect of structural parameters on compression performance of autoclaved aerated concrete: Simulation and machine learning

Autoclaved aerated concrete (AAC) has broad applications in civil engineering due to its lightweight, thermal and sound insulation. However, the relation between the complex random porous structures and the compression performances of AAC is complex, limiting the optimization and application of AAC. In this study, finite element simulation was implemented and validated based on the experimental results. The simulation results showed that the compressive strength of AAC increased by 31.7, 45.8, and 134% with the porosity decreasing from 70% to 40%, the average pore diameter decreasing from 1.5 to 0.5 mm, and the pore connectivity decreasing from 50% to 0, respectively. Then, based on the numerical dataset, integrated machine learning methods were implemented to rapidly predict the compressive properties of AAC and analyze the main factors affecting the compressive properties. The ML results showed that the CatBoost model had the best predictive performance based on the small dataset of simulation results, with an average relative error of 18% and 7% for compressive strength and modulus of AAC, respectively. The component modulus was the most important feature for predicting the compressive strength and modulus of AAC.

Research on the thermal response characteristics of lightweight insulation structure with various shaped lattice units

The study of heat transfer characteristics of various lattice structures is necessary for the lightweight design of lattice structures, which are basic units for integrated insulation-bearing structures in the hypersonic aircraft. In this work, the heat transfer characteristics of six representative volume elements based on single-cell are investigated by numerical and experimental methods. Two lightweight insulation structures are designed using the Gibson-Ashby and tetrakaidecahedron simple-cells, which exhibit superior insulation performance. The thermal response characteristics of two structures are comprehensively investigated. The end face area of the lattice unit significantly influences the insulation performance, with a small end face area leads to a good insulation performances. Compared to the tetrakaidecahedron configuration, the Gibson-Ashby configuration demonstrates a superior insulation performance. The inner wall temperature of the structure containing the Gibson-Ashby lattice unit is consistently lower than that of the structure containing the tetrakaidecahedron lattice unit. In the ground experiments, the maximum relative temperature difference between the inner wall surfaces of the tetrakaidecahedron lattice structure and the Gibson-Ashby lattice structure is 7.6 %, while in the flight experiments, it reaches 18 %. Through heat flux inversion, flight conditions were simulated, and the results show that the temperature on the inner wall surface, which is protected by the lightweight insulation structure, remained below 320 K while the outer wall temperature reaches a high value of 423.6 K. These conclusions provide important references for the lightweight design of aircraft insulation structures.

Optimization of fiber reinforced lightweight rubber concrete mix design for 3D printing

A novel lightweight insulation concrete for 3D concrete printing is developed in this study, which incorporates crumb rubber (R) as a modifier to achieve low density, exceptional thermal insulation properties, and high ductility. The mechanical properties and fiber reinforcement mechanism of lightweight rubber aggregate concrete (CR) are investigated under varying R substitution rates, encompassing compressive strength, flexural strength, tensile strength, and tensile strain of CR. The thermal conductivity test offers insights into the thermal insulation mechanism of CR. The study investigates the compatibility between the material properties of fiber reinforced rubber concrete and the parameter matching of concrete printing equipment, as well as explores the relationship between interlayer bond strength and material composition. The optimal water-binder ratio for 3D printed fiber-reinforced lightweight rubber concrete compatible with printer equipment is determined through fluidity experiments and buildability tests. The findings indicate a statistically significant decrease in CR density by 16.5% when the replacement rate reaches 30%. Although the mechanical strength of CR decrease with the increasing substitution rate of R, the tensile strain showe an increasing trend. The addition of glass fiber reinforcement resulted in a notable enhancement of the mechanical properties and a significant increase in tensile strain for CR. In addition, CR thermal conductivity is reduced by 20.65%, with the excellent thermal insulation performance. This study is of great significance to promote the rational utilization of rubber resources, promote the development of circular economy, and build a conservation-oriented and environment-friendly society.

Abundance and potential sources of floating polystyrene foam macro- and microplastics around Japan

Polystyrene foam is widely used due to its lightweight, impact resistance, and excellent thermal insulation properties. Meanwhile, weak adhesion between beads in polystyrene foam leads to fragmentation, generating a substantial amount of microplastics (<5 mm). Such polystyrene foam debris littered on beaches diminishes the aesthetic value of coastal areas, negatively impacting tourism. Due to its density lower than other plastics, polystyrene foam macroplastics float on the sea surface and, thus, they are significantly influenced by wind drag during oceanic transport. In contrast, polystyrene foam microplastics drifting beneath the sea surface are carried mostly by ocean currents. These properties of polystyrene foam macroplastics and microplastics hinder the elucidation of their transport, distribution, and fate in nature, despite their potential to adversely impact marine ecosystems. To elucidate the generation, transport, and fragmentation processes of polystyrene foam ocean plastics, we conducted concurrent visual observations and surface net towing from seven training vessels around Japan during 2014–2020. Overall, the abundances of polystyrene foam ocean plastics were higher in the Sea of Japan than in the North Pacific south of Japan. The average abundances of polystyrene foam microplastics and macroplastics were 0.33 pieces/m3 and 0.45 pieces/km, respectively, over the entire sea area around Japan. In the Sea of Japan, the peak abundances of polystyrene foam macroplastics occurred in upstream of the Tsushima Current, while the peak for microplastics occurred downstream, suggesting that continuous fragmentation occurred during transport between the two peaks. Backward-in-time particle tracking model experiments suggested that the sources of polystyrene foam macroplastics observed in the Sea of Japan included aquaculture buoys and styrene debris beached around the Tsushima Strait. The present study demonstrated that reducing the release of polystyrene foam aquaculture floats will likely diminish the abundance of ocean plastics in the Sea of Japan.

Lightweight zirconium modified carbon–carbon composites with excellent microwave absorption and mechanical properties

With the rapid development of space technology, multi-functional materials with advantages such as heat insulation, lightweight, and electromagnetic (EM) wave absorption have gained broad application prospects. Since porous carbon fiber reinforced carbon (C/C) composites often have lightweight and high heat insulation properties, improving their mechanical and electromagnetic wave absorbing properties will significantly expand their application. In this study, a new kind of zirconium-modified C/C (Zr-C/C) composites prepared by polymer infiltration and pyrolysis using zirconium-modified phenolic resin is presented. By adjusting the content of Zr, the compressive strengths of the composites are increased up to 48% compared with the composites without Zr, while the thermal insulation properties are little changed. The incorporation of zirconium can make the composites exhibit better microwave absorption performance to some extent, and Zr-C/C composites with 10% zirconium have the best microwave absorption performance among all the samples. The excellent electromagnetic wave absorption performance of Zr-C/C composites is attributed to the enhanced interfacial polarization effect and the improved electrical conductivities of the material due to its internal carbon microsphere structure. Multi-functional Zr-C/C composites that combine lightweight, high thermal insulation, high compressive strength, and high electromagnetic wave absorption have obvious applications in fields such as stealth aircraft. Therefore, this work provides a new way to prepare multi-functional materials.

Energy Performance and Optimization of Commercial Building under Composite Climate using BIM

Abstract: The use of BIM REVIT for Energy Performance and Optimisation of Buildings (EPOBs) has been shown in this research to be a sustainable and energy-efficient response to the problems posed by climate change and growing energy expenses. These buildings are made to produce as much energy as they consume, ensuring that their net energy consumption is zero. The paper explores the evolution of energy performance and optimisation of buildings and the latest emerging technologies that are enabling their development, comprising innovative sensors, lightweight insulation panels, energy-efficient lighting and HVAC systems, building integrated photovoltaic (BIPV) systems, and smart building automation systems. The effectiveness of these strategies is analysed using Autodesk insights and Revit software. In order to ascertain the effectiveness of energy-efficient and renewable energy strategies, the article also compares energy use intensity (EUI) before and after implementation. The proposed building achieved a significant 44.3% reduction in energy consumption after implementing various energy performance and Optimization strategies for commercial building design, resulting in a mean EUI value of -33.1 kWh/sq. m/year. The analysis was conducted using Autodesk Insights and Revit software, utilising the Building Information Modelling (BIM) approach for building design. This paper concludes with a discussion on the future of energy performance and optimisation and how they are an important step towards achieving sustainable and efficient energy use in the building sector, resulting in cost savings and reducing carbon emissions.

Research on the application of lightweight deep learning model in automatic identification of electricity-related public safety hazards in distribution lines

Abstract In view of the current problems of low speed, high network complexity, and difficulty in accurately detecting small target defects in insulator defect detection methods, this study proposes a lightweight insulator defect detection model. First, by enhancing both the convolutional block (CBL) and the efficient long-range aggregation network (ELAN-S) within the feature extraction network, the extraction capability for defect features is significantly augmented. Secondly, the CA-Tiny Spatial Pyramid Pooling (SPP) module was crafted by seamlessly integrating the coordinate attention mechanism with Tiny SPP, enabling the model to prioritize insulator defect characteristics and thereby enhancing defect detection accuracy. Finally, utilizing the positioning loss function WIoUv3 loss for loss calculation, a smaller gradient gain is assigned to low-quality anchor boxes, minimizing harmful gradients and enhancing the model’s positioning performance. Experimental outcomes demonstrate that the enhanced YOLOv7-tiny model excels in rapid and precise defect detection. In comparison to the original YOLOv7-tiny model, the proposed version is well-suited for edge device deployment, enabling real-time insulator defect detection.

Additive manufacturing of novel lightweight insulation refractory with hierarchical pore structures by direct ink writing

A direct ink writing process using fly ash foaming slurries was employed for the additive manufacturing of lightweight mullite insulation refractory with hierarchical pore structures. The viscosity, thixotropy, and shear thinning behavior of the inks were analyzed to investigate the effect of the inorganic binder and dispersant of the foaming inks. A slurry exhibiting excellent rheological characteristics was identified, consisting of 45 wt% fly ash floating beads, 55 wt% water, 3.0 wt% additional dispersant, and 6.0 wt% additional binder. Furthermore, through the optimization of printing parameters such as printing pressure and printing speed, notable enhancements were achieved in the pore structure and properties of the final insulation refractory. Upon heating the lightweight insulation refractory to 1300 °C, the bulk density, compressive strength, and thermal conductivity were determined to be 0.61 g/cm3, 1.01 MPa, and 0.13 W/(m·K), respectively. The direct ink writing technique demonstrates substantial potential in manufacturing lightweight refractories that possess superior thermal insulation and reliable usage strength.

A lightweight and high compressive resistance thermal insulation material with dual-network structure

A lightweight and high compressive resistance thermal insulation material with dual-network structure

Sound insulation enhancement of PVB film by additive engineering

In recent years, noise pollution has become a prominent topic in the energy field. The lightweight and high sound insulation materials have attracted more and more attentions. This study focuses on improving the sound insulation properties of PVB films by adding a little water during the processing. When the water content was 4 %, the average sound transmission loss improved by 5.7 dB at 500–1100 Hz, with a maximum improvement of 17.6 dB, due to porous structure formed by the water additives. Meanwhile, the tensile stress was 28.1 MPa and the elongation at break achieved 140.4 %, which were 1.06 and 1.24 times higher than that of PVB without water, respectively. The porous structure and sound insulation mechanism for PVB films were characterized by SEM, BET and acoustic impedance tubes, etc. .1

Analysis of heat transfer characteristics of sandwich cylindrical shell with an aerogel-metal-rubber composite core

Metal-rubber sandwich cylindrical shell displays a broad range of potential applications in the field of thermal insulation due to its advantages of lightweight, high-temperature stability, and superior high-temperature thermal insulation properties. To optimize the thermal insulation performance of a sandwich cylindrical shell with a metal-rubber core, this study proposes the idea of filling the pores of the metal-rubber with aerogel, thereby forming a composite structure of aerogel and metal-rubber (AMR). Through finite element analysis, the law of internal temperature changes in the AMR composite structure and the distribution laws of the velocity field, viscosity field, and pressure field of the sandwich cylindrical shell under varying wind speeds are investigated. These findings are further verified through heat transfer and forced convection tests. The results reveal that the thermal conductivity of the AMR composite structure at the same density is lower than that of the metal-rubber, and the thermal insulation performance of the AMR composite structure is directly proportional to its density. Meanwhile, through the analysis of forced convection heat transfer in the cylindrical shell, it is found that wind speed has a direct relationship with the pressure field, velocity field, and viscosity field. In addition, there is a relatively high viscosity and a low flow rate near the wall of the cylindrical shell, with a higher flow rate at the axis of the cylindrical shell. At the same wind speed, the temperature rise of the sandwich cylindrical shell shows a positive correlation with an increase in density, and the maximum stable temperature also increases correspondingly. Moreover, at the same density, the thermal conductivity demonstrates a negative correlation with increasing temperature.

Lightweight sound insulation optimization of simply supported locally resonant plate

A theoretical model of the normal sound insulation of a rectangular locally resonant (LR) plate with simply supported boundary conditions is established. The accuracy of the model is verified through comparison with finite element simulation results. Considering a 1-m2 aluminum plate as the research object, a non-dominated genetic algorithm is introduced. The algorithm optimizes the lightweight sound insulation of an LR finite plate with a center frequency band of 20–800 Hz as the optimization objective of maximum average sound insulation and minimum mass. The optimization parameters are substrate thickness and local resonance parameters (including resonator target frequency (fobj), number of resonators, additional mass ratio, and resonator damping). Optimization results indicate that the average sound insulation fluctuates at approximately 2 dB due to changes in fobj. The results also provide an optimal solution to the algorithm. The optimal sound insulation value curve of LR plates corresponding to different surface densities of intermediate improved cases is fitted and compared with the sound insulation value of an equal-mass bare plate. Under lightweight optimization, the resonators are deemed capable of improving the local frequency band sound insulation. In contrast, the wideband average sound insulation can approximate but not surpass the insulation provided by the equal-mass bare plate. In practical applications, an LR plate that can improve the local frequency band sound insulation and ensure the overall lightweight sound insulation performance of the wide frequency band can be obtained. This can be achieved by analyzing the frequency spectrum of optimal points in the lightweight sound insulation optimization process. Relevant research can provide a basis for the evaluation and design of the low-frequency sound insulation of plates for transportation equipment, such as airplanes, high-speed trains, and cars.

A green flame retardant coating based on one-step aqueous complexation of phytic acid and urea for fabrication of lightweight and high toughness flame retardant EPS insulation board

Green flame retardants have drawn much attention because of their environmental friendliness. But for the high flame retardancy of flammable polymers, most existing green flame retardants are unsatisfactory, even the flame-retardant process can not achieve high efficiency and environmental protection. In this work, flame retardants and flame-retardant process are addressed in a two-pronged approach. An eco-friendly bio-based synergistic flame retardant (PAU) was synthesized based on phytic acid (PA) and urea (U) through simple complexation assembly in water. The designed flame retardant coating can be directly coated on the surface of any topological shape with polydopamine as an adhesive. Flame retardant expandable polystyrene (EPS-PAU) with light weight and high toughness is prepared with the designed PAU flame-retardant coating. The coated EPS plates exhibit V-0 UL-94 rating and 42.0 % of limited oxygen index and excellent smoke suppression. Moreover, the density of EPS-PAU is slightly increased only by 2.27 % on the basis of the neat EPS, and the hard shell formed using PDA as an adhesive layer is beneficial for the improvement of impact strength. This novel biomass-based PAU system provides a promising strategy for manufacturing polymer products with excellent flame retardancy, smoke inhibition and light weight.

Multicomponent Si–Zr-based lightweight nanofiber films with a hollow structure exhibiting excellent thermal insulation properties

Hollow-structured ceramic fibers with multiple components are ideal as lightweight insulation materials. In this study, tetraethyl orthosilicate, boric acid, and zirconia octahydrate were used as raw materials for fabricating SiZrBOC hollow ceramic fibers through coaxial electrospinning. These ceramic fibers exhibit a low thermal conductivity and an excellent temperature resistance. The electrospun SiZrBOC hollow ceramic fibers display a clean and compact morphology with internal folds. Fourier-transform infrared spectroscopy and thermogravimetric analysis (TGA) were used to assess the transformation process and thermal behavior of the hollow ceramic fibers. The results suggest that the incorporation of B promotes the formation of Si–O–B bonds within the system, leading to a maximum yield of 75.49 wt% for the production of the SiZrBOC hollow ceramic fibers. The phase composition and microstructure of the SiZrBOC hollow ceramic fibers were analyzed via X-ray diffraction (XRD) measurements. The pyrolysis at 1000 °C resulted in the appearance of diffraction peaks corresponding to SiO2 and SiC in the XRD patterns of the SiZrBOC hollow ceramic fibers. Laser thermal conductivity measurements reveal that the SiZrBOC hollow ceramic fibers exhibit a thermal conductivity of only 0.06 W‧m−1K−1 at 25 °C and 0.124 W‧m−1K−1 at 500 °C, indicating a significantly superior thermal insulation performance compared with conventional solid SiZrBOC ceramic fibers.

A Lightweight Insulator Detection Methodology for UAVs in Power Line Inspection

The defect of insulators on the power line may lead to the failure of the electric transmission system, which in turn endangers the safe and reliable operation of the whole power system. Therefore, timely and accurate detection of insulators has become a current research hotspot. However, manual inspection cannot guarantee real-time detection and is prone to security accidents. Thanks to the convenience of Unmanned Aerial Vehicles (UAVs), collecting insulator images by UAVs and designing detection algorithms on insulators for real-time and accurate insulator detection have become a practical option. In this paper, considering the poor computing resources of UAVs, a lightweight object detection algorithm, NanoDet, is trained to detect insulators. In addition, to fully utilize the computing resources, the proposed model is segmented. Power-efficient layers are mapped to the central processing units (CPUs) for execution. Experimental results indicate that the proposed model can cut down the power consumption by up to 46.4% without violating the time constraint.

Tuning the Degree of Protonation to Prepare Ultra-light and High Thermal Insulation Mullite Nanofiber Aerogels

Ceramic fiber aerogels play an important role in thermal insulation due to their high specific surface area and porosity. They have great potential in aircraft, the military industry, and metal smelting. Although traditional ceramic fiber has the advantages of high-temperature resistance, its brittleness, tensile resistance, and high production cost, greatly limit the application of ceramic aerogels. Using the sol-gel method and electrostatic spinning technique, we controlled the fibers’ random winding and mechanical properties by controlling the protonation of the spinning fluid. We prepared ultralightweight, flexible, and highly insulated mullite nanofiber aerogels with a volume density as low as 7 mg / cm3, thermal conductivity as low as 27 mW m−1 K−1, excellent thermal stability at 1,300 °C, high thermal insulation and retention of up to 50% of the ceramic fiber after initial compression. This material’s fabrication process and excellent insulation properties propose new opinions on the lightweight and durable insulation materials needed for aerospace and military insulation.

Developing fired clay bricks by incorporating scrap incinerated waste and river dredged sediment

The global extraction of several billions of clean clay resources, which destroy millions square meters of land, is triggering environmental problems. Incorporating different dosages of incinerated waste or dredged sediment in bricks production has been studied by many researchers. Research articulating the combined effect of incinerated waste material (IWM) and river dredged sediments (RDS) addition on the performance of bricks is scarce. This paper aims to present findings on the engineering performance of fired bricks developed with the addition of IWM and RDS. In this regard, bricks were made with 5 wt% IWM and different dosages of RDS (i.e., 0 – 15 wt%). Physical, durability, mechanical, thermal and microstructure of the developed bricks is examined. Bricks’ shrinkages were found meeting quality performance criterion in the 1.42 – 4.11% range. The highest bulk density of 1.85 g/cm3 permit to classify bricks obtained as lightweight. Water absorptions were mostly within the acceptable 20% tolerance level postulating the developed bricks high durability standard. Compressive strength reductions, which were confined within 5.28 and 21.57 MPa, showed the developed bricks applicability to structural weight-supporting construction as well as specialized engineering construction works. The 40.5% thermal conductivity reduction in WB15 bricks (at 800 °C) theorized its suitability for thermal insulation construction. Mineralogical and morphological analyses of fired bricks clearly showed kaolinite polymorphic phase transformation, which contributed to the different morphologies in the brick matrices. Consequently, reuse of IWM and RDS offered a chance to advance sustainable use of scarce clay resources in lightweight and thermal insulation brick production.