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While cool coatings have recently received much attention for building applications, their impact on building energy consumption strongly depends upon climatic conditions. Herein we evaluate the energy, cost, carbon, and interior comfort impact of cool coatings applied to a residential multifamily building across 32 climate zones in the United States by applying advanced cool coating properties to established building energy models. The model not only considers promising cool coating properties based upon recent experiments but also an ideal cool coating. Our calculations show that the ideal cool coating can achieve annual cooling energy savings of up to 6.64 kWh/m2 (Phoenix, AZ), annual net utility cost savings up to $1.16/m2 (Brawley, CA), and net annual carbon emission savings up to 7.7 % (Phoenix, AZ). We also estimate the change in interior temperature for buildings without space cooling systems and show that cool coatings make buildings in the warmest climate zones in the U.S. without space cooling more comfortable by 30 % to 50 % on a cooling degree days basis. Using analysis of variance, we examine the statistical relationships between building performance metrics and climatic parameters. The presented methodology enables evaluation of cool coating application to buildings in various climate zones across the world.

In this study, a carbon nanotube‐glass bubble/polyamide 6 (CNT‐GB/PA6) multiscale hybrid composite was manufactured. Through a coagulation process including CNT and GB, a segregated network was formed to produce a composite structure with tunable thermal conductivity. Within the segregated network structure, a complex phenomenon of decrease and increase in thermal conductivity owing to the interaction by CNT and GB, and an equation to predict thermal conductivity through the contents of GB and CNT was formulated. A model to predict the thermal conductivity using the RSM analysis was presented, and the contents of GB and CNT were adjusted according to the required thermal conductivity. It was confirmed through the LFA thermal conductivity measurement that the thermal conductivity increased with GB and CNT contents. Moreover, when 30% of GB was added to the 5 wt% CNT composite, the thermal conductivity increased by about 17%. However, in the experiment to confirm the effect of GB alone, it was confirmed that the thermal conductivity decreased as the GB content increased. Thus, the size of the structural path, which was controlled by the GB content through which electrons pass, played an important role in this study. The results of this study can be used in astronautic fields that require insulation to save energy and in construction engineering where thermal insulation and heat emission are important. [ABSTRACT FROM AUTHOR]

In this warming world, radiative cooling is believed to be one of the most promising techniques for keeping cool without increasing greenhouse gas emissions. Glass bubbles have been proposed as a component of high-performance radiative cooling paints because of the bubbles' controllable size and their enhancement of light scattering. However, the current radiative cooling paints with glass bubbles suffer from low solar reflectivity because of their large particle size. In this study, we propose the idea of breaking the glass bubbles by means of ball milling to enhance the cooling performance of radiative cooling paints. The ball-milling process increases the solar reflectivity from 93.3% to 97.3% with the thermal emissivity of ∼93.4%, while the temperature difference with the ambient air is increased from 1.8 °C to 3.5 °C at noon. When the paint is covered with nanoporous polyethylene film, the temperature is 8.5 °C below the ambient air temperature at noon and 14.1 °C at night. The superior radiative cooling capability of the paint and the record-setting temperature difference achieved in Hong Kong demonstrate its excellent cooling performance, while the simple preparation method and ease of application make this paint promising for commercialization and large-scale production. [Display omitted] • The ball milling process could increase the solar reflectivity from 93.3% to 97.3%. • The temperature difference was increased from 1.8 °C to 3.5 °C at noon. • Record-setting temperature reduction in Hong Kong was achieved. [ABSTRACT FROM AUTHOR]

Various types of additives have been diachronically used in historic mortars, whereas their use in lime-based grouts, used for the restoration of historic structures, is rather limited. In this study, an effort was made to investigate the performance of glass additives in grouts, consisting of lime and natural pozzolan. The additives concerned glass fibers (3 and 6 mm in length), glass beads and bubbles, added in a proportion 0.3–3% w/w of binders. Five grout compositions were manufactured and their properties at fresh and hardened states were tested. From the evaluation of the results, it was asserted that glass additives influenced the grouts’ performance in a favorable way. Their fresh state and physical properties were maintained or slightly improved, while there was a significant enhancement of the long-term mechanical characteristics of the mixes. Additionally, the adhesion capability of grouts was notably increased, which is a crucial aspect indicating their efficacy.

In this study, the ballistic behavior of protective armor plates (PaP) obtained by curing between high structural strength AA7075-T651 aluminum plates by reinforcing with glass balls of two different rubber mixtures whose damping properties were developed with carbon nanotube and glass bubbles fillers were investigated. A total of six PaPs at 27, 30, and 35 mm heights were prepared using two different matrix damping rubbers. High-strength liner rubber used in air bellows is vulcanized on the front and back surfaces of PaPs. Between the PaPs, Ø15.875 and Ø6.747 mm, borosilicate glass balls were placed in a particular arrangement that coincides with the middle of the matrix rubber and does not have any gaps. Liner rubber cured on the front face has managed to hold the energy by forming a layer like clothing around the bullet cores. Glass balls between PAPs play an essential role in the energy absorption of GB-filled mixtures. In contrast, in MWCNT-filled mixtures, they act as a second damping element. The ballistic performance of PAPs prepared with multiwalled carbon nanotubes was determined to be better than those prepared with Glass Bubbles. Thanks to the superior mechanical properties and high aspect ratio of MWCNTs, the penetration and swelling heights of the matrix damping rubbers prepared to have excellent results compared to glass bubbles. With the increase in the thickness of the PaPs prepared with MWCNTs, the deformation effect of the penetration depth and bulging height created by the bullet on the anterior and posterior surfaces decreased. As the thickness of PaP increased from 27 mm to 35 mm, penetration depth decreased by 38%, and bulging height reduced by 35%. The amount of penetration and swelling increased in PaPs using rubber filled with glass bubbles. As the plate thickness increased, the damping feature decreased and the glass balls were activated, and the bullet was stopped. [ABSTRACT FROM AUTHOR]

Liquid metals are of great importance in developing wearable devices and soft robotics owing to its high conductivity and flexibility. However, the high density of such metals turned out to be big concern for many practical situations. With generalized purpose, a new conceptual material as lightweight liquid metal entity, which can be as light as water, is proposed here. For illustration, an unconventionally ultralight material composed of eutectic galliumindium alloys (eGaIn) and glass bubbles is demonstrated, whose density can be reduced below 2.010 even 0.448 g cm‐3, even lighter than water, but still maintains excellent conformability, electric conductivity, and stiffness variety under temperature regulation. Such material is further adopted to build various complicated structures through origami or force regulation, representing various application scenarios and can be reused for eight times without evident loss in function. Based on these tests, buoyancy component for water‐related devices is designed, which offers the functions of a switch and loading element. The lightweight liquid metal entities are promising for making diverse advanced soft robotics and underwater devices in the near future. [ABSTRACT FROM AUTHOR]

The effects of the content of glass bubbles, polybenzene particles, slag, polypropylene fiber and calcium stearate and the water cement ratio on the properties of glass bubbles insulation mortar were studied. The obtained results indicate that the dry apparent density and thermal conductivity of insulation mortar can be reduced by increasing water cement ratio and the content of glass bubbles and polybenzene particles. The increase of water-cement ratio and the content of glass bubbles can reduce the 28 d compressive strength of thermal insulation mortar, with the increase of polybenzene particle dosage, the 28 d compressive strength of thermal insulation mortar gradually increase, but the dosage of slag and different types of polypropylene fiber only increases the 28 d strength of mortar within a certain range. In addition, calcium stearate can significantly reduce the water absorption of thermal insulation mortar. The optimal water cement ratio is 2.1~2.2, and the optimal dosage of glass bubbles, polybenzene particles, slag, polypropylene fiber (staple fiber) and calcium stearate are 42%~46%, 2%, 10%, 0.1% and 2%~4% respectively. [ABSTRACT FROM AUTHOR]

• The ball-milling process could increase solar reflectivity from 75.8% to 95.8%. • Larger glass bubbles can be used to make high-performance radiative cooling paints. • The larger glass bubbles are over 60% cheaper than the original glass bubbles. Radiative cooling technology potentially can be applied to buildings to reduce cooling energy consumption. One general approach to making radiative cooling paints is to mix polymers with reflective materials. However, the high cost of materials has limited the large-scale application of radiative cooling in real scenarios. In this work, we propose another method to make high-performance radiative cooling paint, at a lower cost. This method entails ball-milling larger glass bubbles instead of the commonly used small glass bubbles. Glass bubbles with a median particle size of 47.9 μm were chosen as the component. After only 5 min of ball-milling, the median particle size was reduced to 9.7 μm. The solar reflectivity of paint made from glass bubbles after 5 min of ball-milling increased from 75.8 % (without ball-milling) to 95.8 %. In field tests, radiative cooling paint made from unground 47.9 μm glass bubbles was found to be 9.4 °C warmer than the ambient temperature at noon, while the paint made by 5 min of ball-milling of these glass bubbles achieved a temperature close to that of ambient air. Moreover, the price per unit of weight of 47.9 μm glass bubbles is only 40 % that of the previous 16.1 μm glass bubbles. [ABSTRACT FROM AUTHOR]

In this work, PEDOT: PSS syntactic foams with different glass bubbles (GB) contents were prepared. The effect of the generated microstructure on the electrical conductivity and its thermal stability were experimentally studied. Additionally, a finite element analysis was carried out to determine the effect of microstructures of the syntactic foams on the prediction of their electrical and thermal conductivity. The result of DMSO doping on electrical conductivity was also analyzed. The syntactic foams showed two types of microstructures depending on the content of GB. The most efficient material to conduct the electric field was obtained with 75 wt % of GB because an electrically conductive segregated network was formed. The finite element simulation showed that the microstructure is not the only key factor in improving electrical conductivity; being the intrinsic electrical conductivity of the matrix also very important. Doping with DMSO increased, even more, the electrical conductivity of the foams with high percentages of GB. Finally, the thermal stability was positively influenced by the microstructure with segregated phases and by the low thermal conductivity of the materials. Essentially, this work reveals a novel and more sustainable process for generating materials like aerogels which potentially could be used as thermoelectric material. [Display omitted] • Syntactic foam of PEDOT: PSS with high content of glass increases the electrical conductivity. • Finite Element Analysis could be a powerful tool for predicting the electrical and thermal conductivity of syntactic foams. • Novel and more sustainable process for generating materials like aerogels with potential thermoelectrical applications. [ABSTRACT FROM AUTHOR]

The recycled polypropylene (rPP) materials that meet technical requirements such as reducing the dimensions and improving the tensile, elongation, impact strength, thermal stability, as well as melt processing, are required for the manufacturing industry. In this paper, we studied the mechanical and thermal properties of post-consumer rPP by adding both synthesized thermoplastic elastomers, and glass bubbles (GB) by a melt allowing process. Styrene-butadiene (SBS) and styrene-isoprene (SIS) block-copolymers that had a styrene content of 30 wt% were synthesized by anionic sequential polymerization. The obtained post-consumer rPP composites were characterized by optical microscopy, scanning electron microscopy (SEM), mechanical analyses (tensile, density, hardness, VICAT softening temperature (VST), heat deflection temperature (HDT), dynamic mechanical analysis (DMA), IZOD strength) and thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). Weight reduction and improvement of the tensile, elongation, impact strength, thermal stability, as well as melt processing of post-consumer recycled polypropylene (rPP) properties compounded with thermoplastic elastomers and glass bubbles, sustain the use of these formulations for engineering applications.

The current most efficient solution to extinguish liquid hydrocarbon (class B) pool fires involves fire-fighting foams containing fluorinated surfactants. However, fluorocarbon surfactants are unsafe due to their environmental persistence and negative toxicological/bioaccumulative impact. To this end, we show that fluorine-free aqueous suspensions of Glass Bubbles (GB) modified with hydrophilic polymer grafted layers can efficiently extinguish hydrocarbon pool fires. Namely, GB grafted with poly(oligo (ethylene glycol) methyl ether methacrylate) (POEGMA), GB-G was fabricated employing "grafting-through" and "grafting-from" methods and used to obtain the suspensions. It was found that the GB suspension, with a grafted layer of higher molecular weight and lower grafting density (GB-GL), proved superior to the more densely grafted GB-GH and nongrafted GB-0 system. The GB-GL suspensions displayed less negative spreading coefficients and viscosities lower than those of GB-GH/GB-0 compositions. When siloxane-polyoxyethylene surfactant was added to all GB suspensions, the interfacial properties were dominated by the surfactant, with all suspensions having the same positive spreading coefficient. However, the GB-GL-surfactant composition had the lowest viscosity among the suspensions studied in this work. Specifically, the viscosity of GB-GH and GB-0 suspensions at a shear rate of 77 s -1 was ∼110% and 70% higher than that of GB-GL. Due to the lower viscosity, the GB-GL suspension demonstrated the most efficient spreading over model hydrocarbon solid (polyethylene) and liquid (hexadecane) surfaces when the surfactant was added. The suspension also showed the best performance in the retardation of hexane evaporation when placed over the heated hexane pool. After 50 min, the amount of hexane that evaporated through GB-GH and GB-0 suspensions was ∼8 and 11 times higher, respectively, compared to the GB-GL suspension. We found that the GB-GL-surfactant system was the most efficient GB suspension in extinguishing the fire due to its superior spreading and sealing ability. It was within 10% of fluorine-containing foam's fire extinguishment performance. The GB suspensions are much safer in terms of burnback resistance as a torch applied directly to the suspension after extinguishment could not reignite the fire. The GB material is recyclable, since it can be collected and reused after application to a fire.

Energy-absorbing materials represent an important group of products in the field of increasing the safety of citizens. Research and development including physical properties testing leads to improvement of these materials and protective constructions. Two types of fillers were chosen for testing: macro and microfillers, together with a two-component polyurethane binder. Different recipes of energy absorbing materials were tested and the resulting physico-mechanical properties, namely bulk density and flexural, compressive and impact strength, are listed in this article. Deformation curves were recorded during pressure loading of materials with macrofillers incorporated. Based on these curves, the rate and mode of energy absorption can be predicted. Most samples underwent the Split-Hopkinson pressure bar test which was the crucial method for the determination of impact energy absorption. [ABSTRACT FROM AUTHOR]

Fragmental rock accumulates around the perforation channel and the permeability of this zone decreases during drilling. Underbalanced drilling cleans the perforation channel and increases oil production. A superlight Saraline drill-in fluid produces a pressure differential. Glass bubbles (GB) were used to reduce the density of this fluid. The required viscosity and stability of the fluid were maintained by adding homogenizing and stabilizing agents. Laboratory tests showed that the density of the fluid with a Saraline:GB mass ratio of 60:40 and a homogenizing and stabilizing agent content of 3 and 9 wt. % can be 500 kg/m, i.e., much lower than the density of pure Saraline, 722.2 kg/m. [ABSTRACT FROM AUTHOR]

The recycled polypropylene (rPP) materials that meet technical requirements such as reducing the dimensions and improving the tensile, elongation, impact strength, thermal stability, as well as melt processing, are required for the manufacturing industry. In this paper, we studied the mechanical and thermal properties of post-consumer rPP by adding both synthesized thermoplastic elastomers, and glass bubbles (GB) by a melt allowing process. Styrene-butadiene (SBS) and styrene-isoprene (SIS) block-copolymers that had a styrene content of 30 wt% were synthesized by anionic sequential polymerization. The obtained post-consumer rPP composites were characterized by optical microscopy, scanning electron microscopy (SEM), mechanical analyses (tensile, density, hardness, VICAT softening temperature (VST), heat deflection temperature (HDT), dynamic mechanical analysis (DMA), IZOD strength) and thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). Weight reduction and improvement of the tensile, elongation, impact strength, thermal stability, as well as melt processing of post-consumer recycled polypropylene (rPP) properties compounded with thermoplastic elastomers and glass bubbles, sustain the use of these formulations for engineering applications., Competing Interests: The authors declare no conflict of interest.