Melting Rate Research Articles

Flow regimes in a melting system composed of binary fluid: transition from penetrative convection to diffusion

In a horizontally heated melting system, where a solid substance is subject to melting by a warmer liquid beneath, the presence of solute in the liquid introduces a complex interplay between temperature and concentration dynamics. Employing a recently developed sharp interface method (Xue et al., J. Comput. Phys., vol. 491, 2023), we conduct direct numerical simulations to investigate the transient behaviour of the system across a broad range of Rayleigh numbers and solute concentrations. Our observations reveal distinct flow regimes: at low concentrations, the system resembles a temperature-driven melting problem, characterized by vortex rolls beneath the melting interface. As the solute concentration increases, a stably stratified layer emerges beneath the interface, leading to the transition from thermal convection to penetrative convection, which resembles those flow characteristics observed in the double-diffusive convection. This shift results from the competition between the stabilizing effect induced by solute concentration gradient and the destabilizing effect caused by temperature gradient. Otherwise in the diffusion regime, characterized by very high solute concentrations, the flow becomes static due to the complete suppression of convection by the stably stratified layer. This regime further exhibits two distinct patterns: ‘melting’ and ‘dissolution’. Beyond characterizing diverse flow patterns, our study conducts a quantitative analysis, examining heat/mass transfer, melting rates, and the evolution of temperature and concentration at the interface. These insights contribute to a better understanding of the intricate interplay between temperature and solute concentration during phase change, with implications for accurately estimating melting rates in binary fluid systems.

Improving the charging performance of latent heat thermal energy storage systems using triply periodic minimal surface (TPMS) structures

The utilization of latent heat thermal energy storage (LHTES) using phase change materials (PCM) has attracted considerable attention due to their high energy density and thermal regulation. However, the inferior thermal conductivity of PCM has hindered their widespread implementation, triply periodic minimal surface (TPMS) structures could considerably ameliorate the energy storage utilization. TPMS structures offer escalated surface area and pore interconnectivity, which can enhance the apparent thermal conductivity and improve the performance of LHTES systems. This study focuses on investigating the performance and storage capabilities of three unique TPMS structures, namely Gyroid, IWP, and Primitive, at different relative densities and charging temperatures. The computational model is developed, verified, and validated with the relevant experiment results. A comparative analysis of the temperature distribution and liquid fraction evolution in TPMS LHTES units is carried out and compared to pure PCM LHTES. At a charging temperature of 80 °C, compared to the complete melting time of 7206 s for the pure PCM LHTES, the results demonstrate that the G10, IWP10, and P10-PCM LHTES achieve complete melting at 344 s, 276 s, and 368 s, respectively. This affirms the superiority of IWP structures in improving the melting rates due to their escalated surface areas and tortuous paths. The use of TPMS structures improves the total heat storage, heat storage rate, and volumetric heat storage density, while reducing the gravimetric heat storage density, compared to the pure PCM LHTES. The G10-PCM LHTES attains total heat storage, heat storage rate, volumetric, and gravimetric heat storage density of 2120 J, 6.16 W, 63.6 kWh/m3, and 227 kJ/kg, compared to 1910 J, 0.27 W, 57.3 kWh/m3, and 250 kJ/kg for pure PCM LHTES, respectively. Moreover, increasing the relative density of TPMS structures adversely reduces the total heat storage, heat storage rate, and volumetric heat storage density, and significantly increases the heat storage rates. As the charging temperature increases, the complete melting time is reduced and the charging performance indicators are improved, for the pure PCM and TPMS-PCM LHTES units.

Melting and solidification in periodically modulated thermal convection

Melting and solidification in periodically time-modulated thermal convection are relevant for numerous natural and engineering systems, for example, glacial melting under periodic sun radiation and latent thermal energy storage under periodically pulsating heating. It is highly relevant for the estimation of melt rate and melt efficiency management. However, even the dynamics of a solid–liquid interface shape subjected to a simple sinusoidal heating has not yet been investigated in detail. In this paper, we offer a better understanding of the modulation frequency dependence of the melting and solidification front. We numerically investigate periodic melting and solidification in turbulent convective flow with the solid above and the melted liquid below, and sinusoidal heating at the bottom plate with the mean temperature equal to the melting temperature. We investigate how the periodic heating can prevent the full solidification, and the resulting flow structures and the quasi-equilibrium interface height. We further study the dependence on the heating modulation frequency. As the frequency decreases, we found two distinct regimes, which are ‘partially solid’ and ‘fully solid’. In the fully solid regime, the liquid freezes completely, and the effect of the modulation is limited. In the partially solid regime, the solid partially melts, and a steady or unsteady solid–liquid interface forms depending on the frequency. The interface height can be derived based on the energy balance through the interface. In the partially solid regime, the interface height oscillates periodically, following the frequency of modulation. Here, we propose a perturbation approach that can predict the dependency of the oscillation amplitude on the modulation frequency.

Understanding photo-thermal and melting mechanisms in optical charging of nano and micro particles laden organic PCMs

Engineering efficient optical charging process necessitates efficient photo-thermal energy conversion, transfer, as well as storage of the incident solar radiant energy. The present work is a determining step in deciphering, quantifying, and understanding the aforementioned steps involved in the optical charging of PCMs. Herein, the effect of particle size, concentration and thermochromism have been critically investigated. In particular, detailed optical characterization and photo-thermal experimentation pertinent to non-thermochromic nanoparticles laden PCM (referred to as NP-PCM) and thermochromic micro capsules laden PCM (referred to as TMCP-PCM) has been undertaken. Detailed optical analysis points out that opposed to NP-PCM, TMCP-PCM significantly scatter the incident radiations – the diffuse transmittance (at room temperature) in the two cases being approximately 2 % and 39 % respectively. Furthermore, whereas, optical properties of non-thermochromic nanoparticles are nearly invariant to temperature changes; in the case of thermochromic microcapsules, the magnitude of scattering further increases and diffuse transmittance reaches as high as 51 % at elevated temperatures. Although, thermochromism helps in enhancing the penetration depth at elevated temperatures, but, due to significant fraction of scattering, the photo-thermal energy conversion is not that effective. In terms of temperature field, spatial-temporal temperature distribution curves reveal that temperature spread (in the liquid phase) in case of optical charging of non-thermochromic particles (carbon soot nanoparticles) laden PCMs is significantly high (as high as approximately 24 °C) relative to that observed in case of thermochromic particles (microcapsules) laden PCMs (approximately, 4 °C). The magnitude of the temperature spread (being representative of the deviation from thermostatic optical charging) clearly points out that opposed to non-thermochromic laden PCMs, nearly thermostatic optical charging can be achieved in case of thermochromic particles laden PCMs.Furthermore, in case of optical charging without thermochromic assistance, the temperature spread, peak temperatures and the melting rates increase with increase in particles concentration. Whereas, in the latter case, although the temperature spread and peak temperatures are nearly independent; the melting rates do depend on the particles’ concentration. Overall, the present work is a significant step towards accelerated-thermostatic thermal energy storage.

CFD Modeling of HBI/SCRAP Melting in Industrial EAF and the Impact of Charge Layering on Melting Performance

The melting of scrap and hot briquetted iron (HBI) in an AC electric arc furnace (EAF) is simulated by an advanced 3D computational fluid dynamics (CFD) model that captures the arc heating, the scrap/HBI melting process, and the solid collapse mechanisms. The CFD model is used to simulate a scenario where charge layering and EAF power profiles are provided by a real EAF operation. CFD simulation of the EAF operation shows proper prediction of the charge melting when compared with standard industry practice. Namely, the CFD model predicts a 32.5%/67.5% ratio of solid/liquid steel at the beginning of refining, which approaches the 30%/70% ratio used in standard practice. Based on this prediction, the melting rate in the CFD results differs by 8.3% from actual EAF operation. The impact of charge layering on melting is also investigated. CFD results show that distributing charge material into a greater number of layers in the first bucket (10 layers as compared to 4) enhances the melting rate by 12%. However, including dense material at the bottom of the furnace deteriorates melting performance, reducing the impact of the number of layers of the charge. The CFD platform can be used to optimize the use of HBI/scrap in real EAF operations and to determine best recipe practices.

On the factors and the degree of their effect on subglacial melt and changes in the state of Antarctic subglacial lakes

ABSTRACT This study presents the results of mathematical modeling of the degree of effects of various characteristics on basal conditions in Antarctica. The model is based on the numerical solution of the one-dimensional Stefan problem. Five factors determining the nature of subglacial processes have been studied: ice thickness, snow-firn thickness, surface mass balance, air temperature, and geothermal heat flux. It was found that on the Antarctic plateau, slope, and coast, the geothermal heat flux has the greatest influence on the basal conditions. It is the heat flux that is responsible for the transition of most Antarctic lakes from a stable state to an active one (except for the ice stream regions). In areas where the ice sheet is thinner than 1,500 m, air temperature is the second most important factor affecting subglacial conditions. In areas where the glacier is thicker, the ice thickness begins to have a greater effect. The snow-firn thickness and snow accumulation have little effect on subglacial melt in most parts of Antarctica. Calculations over a 100-year period show that if meltwater accumulates on the bedrock rather than being completely channeled, it leads to a decrease in the average rate of subglacial melting by approximately 10 times.

Deriving iceberg ablation rates using an on-iceberg autonomous phase-sensitive radar (ApRES)

Abstract The increase in iceberg discharge into the polar oceans highlights the importance of understanding how quickly icebergs are deteriorating and where the resulting freshwater injection is occurring. Recent advances in quantifying iceberg deterioration through combinations of modeling, remote sensing and direct in situ measurements have successfully calculated overall ablation rates, and surface and sidewall ablation; however, in situ measurements of basal melt rates have been difficult to obtain. Radar has successfully measured iceberg thickness, but repeat measurements, which would capture a change in iceberg thickness with time, have not yet been collected. Here we test the applicability of using an on-iceberg autonomous phase-sensitive radar (ApRES) to quantify basal ablation rates of a large (~800 m long) non-tabular Arctic iceberg during an intensive 2019 summer field campaign in Sermilik Fjord, southeast Greenland. We find that ApRES can be used to measure basal ablation even over a short deployment period (10 d), and also provide a lower bound on sidewall melt. This study fills a critical gap in iceberg research and pushes the limits of field instrumentation.

Experimental study on the melting characteristics modulation of cubic ice cubes with different trace air contents under natural convection condition

Ice as a typical phase change material has the advantages of low cost, high latent heat and environmental friendliness, and the ice melting process under natural convective conditions is a fundamental study that has received wide attention. For the cubic ice cubes having different air contents, their melting characteristics becomes more complicated. The melting model of cubic ice under natural convection conditions was developed, which can accurately predict the time of the entire melting process. To validate the accuracy of the model, a series of melting experiments on cubic ice cubes are conducted and analyzed, with mass and air contents varied from 20 g to 50 g, and from 0 to 3.9 %, with a model error of less than ±20 %. Based on the maximum melt rate and the change in shape to a pyramid of cubic ice, the melting process can be divided into the initial melting, frustum-shaped, and pyramid-shaped stages. Varying the air content of the ice regulated the total melting time and the time proportion of the initial melting stage and the frustum-shaped stage of the ice. The proportion of time in the pyramid-shaped stage decreased from 64.3 % to 51.5 % for bubble ice with an air content of 3.9 % compared to clear ice. The proportion of time in the pyramid-shaped stage during the ice melting process is not significantly related to the air content and mass, and remains at approximately 27 %. Results of this study are meaningful for regulating the melting process and optimizing phase change energy storage technologies.

Bacterial cellulose infusion: A comprehensive investigation into textural, tribological and temporal sensory evaluation of ice creams

The study examines how adding bacterial cellulose also referred to as Symbiotic Culture of Bacteria and Yeast (SCOBY) to ice cream affects the textural, tribological, and sensory attributes, particularly texture and mouthfeel perception. Analytical assessments were performed on three types: SCOBY-added ice cream and two reference samples (control and guar gum-added ice creams). Evaluations included physicochemical properties, textural and tribological characteristics, and dynamic sensory mouthfeel using the temporal dominance of sensation (TDS) methodology. SCOBY ice cream showed higher probiotics content, lower pH, and higher acidity than reference samples. The addition of SCOBY increased hardness and altered the textural properties. TDS analysis highlighted distinct temporal dominance patterns, with guar gum ice cream presenting a pronounced mouth/residual coating pre-swallowing, while SCOBY and control ice cream exhibited a thin/fluid perception. The frictional factor at 37 °C was positively correlated with the melting rate, graininess, and thin/fluid perception while negatively correlated with firmness, smoothness and mouthfeel liking. Additionally, the mouthfeel liking was higher with firm, smooth and mouth/residual coating sensations and lower with grainy and thin/fluid perception. In summary, incorporating SCOBY in ice cream formulations can provide health benefits and meet consumer preferences for natural ingredients, while ensuring careful optimization of mouthfeel.

Optimization of a finned multi-tube latent heat storage system using new structure evaluation indexes

The latent heat thermal energy storage (LHTES) is one of the most promising ways of storing solar thermal energy. Since the thermal conductivity of phase change materials are low, traditional shell and tube heat exchangers tend to develop dead zones. Therefore, structural optimization is essential, and a finned multi-tube design is recommended. In this work, nineteen structures for a heat storage tank are designed to explore the influence of different specifications of heat exchange tubes and fins on heat storage/release performance. After establishing 3D physical models, ANSYS/Fluent simulation and a two-step optimization for charging and discharging processes were conducted. Among these structures, N3-M3-D10.2 emerged as the most efficient during charging process in terms of reducing the complete melting time by 25 % and increasing the 3-h heat storage volume by 2.95 times; however, it shows low performance during discharging process, especially with a 2.24 times non-uniformity factor. In the four preferred structures, the benefit-to-cost ratio of N3-M3-D10.2 is 48 %–86.6 % higher than that of the others. The results also show that the number of tubes and fins are negatively related to the melting rate, and positively related to the solidification rate. Moreover, the influence of fin diameter is greater than that of fin number and tube diameter on heat transfer rate. The novelty of this work is not only lies in both considering the charging and discharging processes, but also in using dimensionless normalized indexes and different weights based on customers’ actual requirements for optimization.

Influence of Brown Rice, Pea, and Soy Proteins on the Physicochemical Properties and Sensory Acceptance of Dairy‐Free Frozen Dessert

ABSTRACTFat and protein derived from milk are prime ingredients in a frozen dessert such as ice cream conferring multiple desirable functionalities. However, this frozen dairy dessert is not suitable for individuals having lactose intolerance, cow milk allergy, or vegans. Hence, the study aimed to formulate dairy‐free frozen desserts using plant oils and plant proteins and compare their physicochemical characteristics and sensory acceptance against an ice cream containing milk fat and milk protein. Results indicated that the types of protein significantly influenced the physicochemical properties and sensory acceptance of the frozen dessert samples. Frozen desserts containing brown rice, pea, and soy protein showed greater resistance to melting (0.29, 0.12, and 0.19%/min vs. 1.95%/min), but they scored lower in sensory quality than ice cream made with milk protein; although they remained at an acceptable level. When compared among the plant proteins, the physicochemical characteristics of frozen desserts containing brown rice, pea, and soy protein varied because of the differences in the respective protein composition. Frozen dessert with brown rice protein showed higher overrun (47.50% vs. 40.78% and 37.8%), lower hardness (20.02 N vs. 22.24 and 26.37 N), and higher melting rate (0.29%/min vs. 0.19 and 0.12%/min) than frozen desserts containing soy and pea protein. Additionally, the brown rice protein frozen dessert received lower sensory acceptance than soy and pea protein frozen desserts. In summary, brown rice, pea, and soy proteins showed potential to be used as viable alternatives to milk protein for dairy‐free frozen dessert applications.

How to infer ocean freezing rates on icy satellites from measurements of ice thickness

Abstract Liquid-water oceans likely underlie the ice shells of Europa and Enceladus, but ocean properties are challenging to measure due to the overlying ice. Here, we consider gravity-driven flow of the ice shells of icy satellites and relate this to ocean freeze and melt rates. We employ a first-principles approach applicable to conductive ice shells in a Cartesian geometry. We derive a scaling law under which ocean freeze/melt rates can be estimated from shell-thickness measurements. Under a steady-state assumption, ocean freeze/melt rates can be inferred from measurements of ice thickness, given a basal viscosity. Depending on a characteristic thickness scale and basal viscosity, characteristic freeze/melt rates range from around O(10−1) to O(10−5) mm/year. Our scaling is validated with ice-penetrating radar measurements of ice thickness and modelled snow accumulation for Roosevelt Island, Antarctica. Our model, coupled with observations of shell thickness, could help estimate the magnitudes of ocean freeze/melt rates on icy satellites.

Melt sensitivity of irreversible retreat of Pine Island Glacier

Abstract. In recent decades, glaciers in the Amundsen Sea Embayment in West Antarctica have made the largest contribution to mass loss from the entire Antarctic Ice Sheet. Glacier retreat and acceleration have led to concerns about the stability of the region and the effects of future climate change. Coastal thinning and near-synchronous increases in ice flux across neighbouring glaciers suggest that ocean-driven melting is one of the main drivers of mass imbalance. However, the response of individual glaciers to changes in ocean conditions varies according to their local geometry. One of the largest and fastest-flowing of these glaciers, Pine Island Glacier (PIG), underwent a retreat from a subglacial ridge in the 1940s following a period of unusually warm conditions. Despite subsequent cooler periods, the glacier failed to recover back to the ridge and continued retreating to its present-day position. Here, we use the ice-flow model Úa to investigate the sensitivity of this retreat to changes in basal melting. We show that a short period of increased basal melt was sufficient to force the glacier from its stable position on the ridge and undergo an irreversible retreat to the next topographic high. Once high melting begins upstream of the ridge, only near-zero melt rates can stop the retreat, indicating a possible hysteresis in the system. Our results suggest that unstable and irreversible responses to warm anomalies are possible and can lead to substantial changes in ice flux over relatively short periods of only a few decades.

Modelling the effect of free convection on permafrost melting rates in frozen rock clefts

Abstract. This research develops a conceptual model of a karst system subject to mountain permafrost. The transient thermal response of a frozen rock cleft after the rise in the atmospheric temperature above the melting temperature of water is investigated using numerical simulations. Free convection in liquid water (i.e. buoyancy-driven flow) is considered. The density increase in water from 0 to 4 °C causes warmer meltwater to flow downwards and colder upwards, resulting in significant enhancement of the heat transferred from the ground surface to the melting front. Free convection increases the melting rate by approximately an order of magnitude compared to a model based on thermal conduction in stagnant water. The model outcomes are compared qualitatively with field data from the Monlesi ice cave (Switzerland) and confirm the agreement between real-world observations and the proposed model when free convection is considered.

Effects of different processing methods on physicochemical and microbiological properties of kefir ice cream

In this study, kefir ice cream was produced using two different methods. In method 1, the ice cream mixture was incubated with kefir starter culture until a pH value of 6.1 or 5.5 was reached, and in method 2, the ice cream mixture was blended with kefir to reach a pH value of 5.5 or 6.1. Kefir ice cream produced by method 2 had a higher overrun and lower firmness than that produced by method 1. When comparisons were made based on the pH value of the ice cream mixture, kefir ice cream produced from the ice cream mixture with a pH of 6.1 instead of 5.5 had a higher overrun and melting rate and a lower firmness. The slightly higher counts on MRS agar, M17 agar, MSE agar, DSM 254 medium, and YGC agar were determined in the kefir ice cream samples produced by method 1 or produced from an ice cream mixture with a pH of 5.5. Although it is unknown if the number of bacteria on MRS agar detected in the samples, where the number was greater than 6 log cfu g−1 even after 90 days of storage, are probiotics or not, kefir ice cream has the potential to be a probiotic product. In this study, it has been demonstrated that kefir ice creams with different physicochemical and microbiological properties can be produced by altering the ice cream production method and pH value of the ice cream mixture.

Thermal performance and flash point analyses of concentrator photovoltaic (CPV) system using multiple types of PCMs and various panel inclination angles under the effect of a constant heat flux

This numerical study conducts a comparative analysis of various phase change materials (PCMs) including Lauric Acid, Paraffin, RT 24, RT 31, RT 35, RT 38, RT 42, RT 47, RT 50, and Lithium Nitrate Trihydrate (LiNO3.3H2O) to assess their suitability for optimizing the thermal management of a solar concentrator photovoltaic (CPV) system. The analysis focuses on the temperature regulation capabilities, melting dynamics of the used PCMs, along the electrical efficiency of the CPV system across a range of inclination angles (0°, 15°, 30°, 45°, 60°, 75°, and 90°) under a constant heat flux of 1000 W/m². The research aims to identify the most effective solutions for enhancing the efficiency and reliability of solar concentrator systems. Key considerations such as PCM’s flash points, liquid fraction and convective behavior are addressed for each PCM type. Numerical results obtained using ANSYS Fluent indicate that Lithium Nitrate Trihydrate (LiNO3.3H2O) outperformed most paraffin-based PCMs, such as RT 24 and RT 35, with around 24 % higher electrical efficiency. Although Lauric Acid was approximately 19.5 % less efficient than Lithium Nitrate Trihydrate, it offered superior long-term thermal stability due to its slower melting rate and phase change temperature of 43–44°C, taking 45.33 % longer to melt compared to Paraffin RT 24. RT 50, with its higher melting temperature of 50°C, provided a balance between melting period and efficiency, making it an ideal PCM for applications requiring both moderate efficiency and sustained thermal regulation.

Maximizing thermal management of photovoltaic-thermal systems with proper configuration of porous fins and phase change materials

Effective thermal management is crucial to enhance the performance and longevity of photovoltaic-thermal (PVT) systems. Phase change materials (PCMs) offer a promising solution for absorbing excess heat from PV modules; however, their poor thermal conductivity limits their effectiveness. This work explores the incorporation of porous fins within PCMs to improve heat absorption and thermal regulation in PVT systems. A detailed mathematical model is developed to analyze the effects of varying fin porosity (0.85 to 0.95), fin thickness (7 to 21 mm), fin height (7 to 21 mm), and fin inclination (-15° to 30°) on PCM melting and PVT cooling performance. Results show that optimally configured porous fins significantly enhance PCM melting rates and heat extraction from PV cells. Incorporating optimal fins reduces peak PV temperatures by up to 5°C compared to PCM alone at irradiation rate of 1000 W/m2. Meanwhile, reducing the fin thickness from 21 to 7 mm accelerates the overall PCM melting rate by 14%. The cooling performance also shows a nonlinear increase with fin tilt angle, with maximum enhancement occurring at 15° downward tilt for the studied configuration. The optimized fin-enhanced PVT design achieves 3.1% higher electrical efficiency and 15% increase in thermal efficiency compared to conventional PCM-PVT systems without fins. Findings provide design guidance to harness porous fins for maximized PCM-based cooling of PVT systems.

Accelerated glacier mass loss in the mid-latitude Eurasia from 2019 to 2022 revealed by ICESat-2

The dynamics of glaciers serve as one of the most important indicators of climate change. Whilst current research has primarily concentrated on long-term interannual glacier mass balance and its response to climate change, glaciers may respond more rapidly to climate change, highlighting the urgent need for intra-annual mass balance estimations. Investigating seasonal or short-term variations in glacier mass balance not only enhances our understanding of the interactions between glaciers and the climate system but also provides crucial data for water resource management and ecological protection. The ICESat-2 and NASADEM datasets were used to estimate the inter- and intra-annual glacier mass balance changes in the mid-latitude Eurasia from 2019 to 2022. Additionally, the response of glacier mass balance to regional air temperature and precipitation values was analysed using ERA5-Land data and multiple regression analysis, respectively. From 2019 to 2022, glacier mass loss in mid-latitude Eurasia reached −45.02 ± 34.21 Gt per year, contributing to a global sea-level rise of 0.12 ± 0.09 mm per year. The glacier melt rate in the study area from 2019 to 2022 was 2.33 times higher than that from 2000 to 2019. With the exception of the Western Kunlun region, which experienced a weak accumulation rate of 0.04 ± 0.35 m w.e. per year, all other areas experienced ablation states. Seasonal mass balance responds differently to temperature and precipitation variations across seasons: higher temperatures in different seasons lead to more negative mass balances, while increased winter and spring precipitation can slow down glacier melt. Air temperature dominates the glacier mass balance changes in the study area. The intense heat in 2022 raised average glacier temperatures by 1.04 °C compared to 2019–2021, resulting in a more negative mass balance and an increased ice loss of −0.34 ± 1.01 m w.e. per year (−35.07 ± 103.22 Gt per year). This analysis indicates that glacier mass balance is highly sensitive to climate change, even on a seasonal scale. Moreover, the high precision and spatiotemporal resolution ICESat-2 data can facilitate the investigation of large-scale glacier mass balance on short time scales.

Characteristics of ice cream from black soybean sprout juice – red dragon fruit with yolk emulsifier

Black soybean germination into sprouts reportedly improved nutrition digestibility and bioactive compound content. Red dragon fruit (RDF) and egg yolk (EY) can be used as natural and halal colorants and emulsifiers. Black soybean sprout (BSS) juice made non-dairy ice cream with red dragon fruit and egg yolk as an emulsifier. This research aimed to measure the effect of various red dragon fruit and egg yolk concentrations on the characteristics of ice cream made from BSS juice. A completely randomized design was applied to six formulations made using the ratio of RDF : EY of FA (20%: 3%), FB (20%: 4%), FC (20%: 5%), FD (40%: 3%), FE (40%: 4%), and FF (40%: 5%). BSS juice was made using 48 hours of room temperature incubated sprout and water at a 1:4 (b/v) ratio. Filtrate was then mixed with sugar, cornstarch, and salt into a dough, which was then mixed with RDF and EY at various concentrations. Nutritional proximate composition, radical scavenging activity, phenolic content, total anthocyanin content, vitamin C, and sensory acceptance were analyzed. Data was then statistically analyzed using one-way ANOVA, followed by Duncan’s Multiple Range Test. Results showed that higher RDF significantly changed overrun, melting rate, increased moisture content, vitamin C (20.4 – 40.23 mg/100 g), antioxidant activity (34.9 – 62.78 % radical scavenging activity), total phenolics (0.341 – 0.536 mg/g GAE), and total anthocyanin (3.905 – 9.726 mg/kg), and hedonic score, but shorter melting time. The shortest melting time was obtained by ice cream made using 20% RDF and 5% EY, the lower concentration of fruit, and the highest concentration of egg yolk, respectively. The results indicated that BSS juice could be used as the main ingredient to make non-dairy ice cream, with red dragon fruit and egg yolk as natural colorants and emulsifiers, respectively. Keywords: Black soybean sprout, Non-dairy ice cream, Red dragon fruit

Microplastic and Associated Black Particles From Road‐Tire Wear: Implications for Radiative Effects Across the Cryosphere and in the Atmosphere

AbstractThe environmental effects of airborne micro‐ and nano‐size plastic particles are poorly understood. Microscopy and chemical analyses of atmospherically deposited particles on snow surfaces at high elevation (2,865–3,690 m) in the Upper Colorado River basin (UCRB; Colorado Rocky Mountains) revealed the presence of black substances intimately associated with microplastic fibers, particles interpreted to have originated as tire matter. Identical and similar particles occur in shredded tires and road‐surface samples. The substance responsible for the black color of all tires is carbon black, a graphitic light‐absorbing tire additive produced by hydrocarbon combustion that homogeneously permeates the mixture of tire polymers and other additives. Such black tire matter may thus exert radiative effects closely similar to those of black carbon. The presence in snow of many organic compound types common to tires, measured by two‐dimensional gas chromatography, suggests that atmospherically deposited black road‐tire‐wear matter is among the light‐absorbing particulates that advance the onset and rate of snow melt in the UCRB. The mass of road‐tire‐wear particles shed from vehicles may be estimated by multiplying measured amounts of eroded tire‐per‐distance traveled by vehicular distances. Under a combination of measurements and assumptions about the amounts and radiative properties of atmospheric tire‐wear particles, the radiative effects of these particles might add about 10%–30% to those effects from black carbon, an estimate ripe for revision. On regional and global scales, the amounts and effects of emitted and deposited tire‐wear matter likely vary by factors of geographic source, transport pathway, and depositional setting.