Estimate Of Total Energy Research Articles

Changes in food and drink purchasing behaviour in England during the first three months of the COVID-19 pandemic: An interrupted time series analysis.

This study examined changes food and drink purchasing during the first three months of the COVID-19 pandemic in England, and if changes varied by population subgroups. We investigated changes in take-home food and drink purchasing and frequency of out-of-home purchasing using an interrupted time series analysis design. The start of pandemic restrictions (the intervention) was defined as 16th March 2020, when first announced in the UK. London and the North of England. 1,245 households reporting take-home and 226 individuals reporting out-of-home purchases between January 2019 and mid-June 2020 from the GB Kantar Fast Moving Consumer Goods Panel. The marginal mean estimate of total take-home energy purchased was 17.4% (95% CI 14.9, 19.9) higher during the pandemic restriction period compared to the counterfactual. Increases of 35.2% (95% CI 23.4, 47.0) in take-home volume of alcoholic beverages and 1.2% (95% CI 0.1, 2.4) in foods and drinks high in fat, salt and sugar were observed. Reductions in purchased energy from fruit and vegetables (-7.3%, 95% CI -10.9, -3.6), ultra-processed foods (-4.0%, 95% CI -5.2, -2.8), and in out-of-home purchasing frequency (-44.0%, 95% CI -58.3, -29.6) were observed. Changes in chocolate and confectionery, soft drink and savoury snack purchases levelled off over time. Changes in all studied outcomes varied by sociodemographic characteristics and usual purchasing. Pandemic restrictions were associated with positive and negative changes in food and drink purchasing, which differed by individual characteristics. Future research should ascertain if changes persist and translate into changes in health.

Mechanical power made simple: validating a simplified calculation of mechanical power in preterm lungs.

The incidence of chronic lung disease is increasing, suggesting a need to explore novel ways to understand ventilator induced lung injury (VILI) in preterm infants. Mechanical power (MP) is a unifying measure of energy transferred to the respiratory system and a proposed determinant of VILI. The gold-standard method for calculating MP (geometric method) is not feasible in the clinical setting. This has prompted the derivation of simplified equations for calculating MP. To validate the agreement between a simplified calculation of MP (MPSimple) and the true MP calculated using the geometric method (MPRef). MPSimple and MPRef was calculated in mechanically ventilated preterm lambs (n = 71) and the agreement between both measureswas determined using intraclass correlation coefficients (ICC), linear regression, and Bland-Altman analysis. A strong linear relationship (adjusted R2 = 0.98), and excellent agreement (ICC = 0.99, 95% CI = 0.98-0.99) between MPSimple and MPRef was demonstrated. Bland-Altman analysis demonstrated a negligible positive bias (mean difference = 0.131 J/min·kg). The 95% limits of agreement were -0.06 to 0.32 J/min·kg. In a controlled setting, there was excellent agreement between MPSimple and gold-standard calculations. MPSimple should be validated and explored in preterm neonates to assess the cause-effect relationship with VILI and neonatal outcomes. Mechanical power (MP) unifies the individual components of ventilator induced lung injury (VILI) and providesan estimate of total energy transferred to the respiratory system during mechanical ventilation. As gold-standard calculations of mechanical power at the bedside are not feasible, alternative simplified equations have been proposed. In this study, MP calculated using a simplified equation had excellent agreement with true MP in mechanically ventilated preterm lambs. These results lay foundations to explore the role of MP in neonatal VILI and determine its relationship with short and long term respiratory outcomes.

Theoretical study of long-range ordered vacancy distribution in two-dimensional boron structures

<sec>In a two-dimensional boron structure, the ordered high-concentration vacancy distribution can enhance structural stability and significantly modulates material properties. Based on recent experimental progress, herein we particularly focus on the two-dimensional boron structures with a striped distribution of hexagonal vacancies, in order to explore the formation of long-period boron structures.</sec><sec>Utilizing the structures of alloy generation and recognition (SAGAR) program developed by our group, we eliminate duplicate structures according to the structural symmetry to reduce computational cost. An effective model system is proposed to investigate the effect of vacancy distribution on the stability of the system, where the interactions between vacancies are utilized for estimating the total energy. By selecting structures with appropriate concentrations and combining first-principles calculations, the parameters in the model are fitted for different vacancy neighbor interactions, which can be further used to predict stable structures at various vacancy concentrations. The feasibility of model analysis is emphasized for structural screening, showing the good agreement between the parameterized model and the first-principles calculations.</sec><sec>Interestingly, under the same vacancy concentration, stable boron structures with different cell sizes exhibit distinct vacancy distributions, indicating a trend of long-period distribution for ground state structures. To address this phenomenon, when the stable candidate structures from the 1/6 series are dominant in number within the computable range and the changes in neighbor statistics can be clearly seen, we select the structures from this concentration series for detailed calculations.</sec><sec>The calculation results indicate that the convergence of the average energy is primarily influenced by the interaction between the fourth nearest neighbor and the sixth nearest neighbor. When considering only these two neighbors, the system energy changes with the increase of cell size as follows: the average energy of structures with a cell size being an even multiple of the minimum cell size keeps unchanged, while the average energy of structure with a cell size being an odd multiple of the minimum cell size gradually decreases, eventually converging to a stable value. When including the interactions between the ninth nearest neighbor and the tenth nearest neighbor, the average energy of structures with a cell size being an even times the minimum cell size also decreases gradually. The average energy decreases with oscillations, with the magnitude gradually diminishing and eventually stabilizing. This discovery reveals that the enhanced stability of long-period structures is attributed to the competitive interactions among different neighboring vacancies.</sec>

Changes in food and drink purchasing behaviour in England during the first 3 months of the COVID-19 pandemic: an interrupted time-series analysis

BackgroundRestrictions related to the COVID-19 pandemic affected many health behaviours, including diet. We aimed to examine changes in food and drink purchasing during the first 3 months of the COVID-19 pandemic in England. MethodsIn this interrupted time-series analysis, we used transaction-level purchasing data for food and drink items bought for at-home (n=1245 households) and out-of-home consumption (n=226 individuals) for London and the North of England (Kantar GB). Outcomes included household-level weekly purchased total energy, energy from specific products, alcohol volume, and frequency of out-of-home purchasing occasions. We compared purchases between March 16 and June 11, 2020 (pandemic restrictions, the intervention) and Jan 1, 2019, to March 15, 2020 (counterfactual). The effect of the intervention was modelled using 2-part negative binomial regression models adjusted for time, season, festivals, region, and sociodemographic characteristics. Subgroup analyses explored interactions between the intervention and sociodemographic characteristics and usual purchasing levels. FindingsThe marginal mean estimate of total take-home energy purchased was 17·4% (95% CI 14·9–19·9; 6130 kcal) higher during the intervention period than during the counterfactual period. Increases of 35·2% (23·4–47·0; 505 mL) in take-home volume of alcoholic beverages and 1·2% (0·1–2·4; 165 kcal) in foods and drinks high in fat, salt, and sugar were observed. Reductions in purchased energy from ultraprocessed foods (–4·0%, –5·2 to –2·8; –541 kcal), and out-of-home purchasing frequency (–44·0%, –58·3 to –29·6; –0·6 days) were observed. Highest socioeconomic status was associated with largest increases in total purchased energy (increase of 7217 kcal, 95% CI 5450–8985, vs 2479 kcal, 935–4023, among low socioeconomic status), while older age groups reported fewer changes in purchasing. Higher usual purchasing levels were associated with greater reductions during pandemic restrictions and vice versa, except for the absolute difference in alcohol purchasing, which increased the most for those with higher pre-pandemic purchasing (lowest 123·2 mL, 95% CI 71·3–175·0; highest 708·3 mL, 381·3–1035·3). InterpretationPandemic restrictions were associated with marked changes in purchasing, notably increases in energy and alcohol and decreases in ultra-processed-food and out-of-home purchasing, which differed by individual characteristics. Future research should ascertain if changes persisted, if these changes translate into changes in health, and whether other regions experienced similar effects. FundingNational Institute for Health and Care Research (NIHR) School for Public Health Research (SPHR).

Validation of the Ocean Wave Spectrum from the Remote Sensing Data of the Chinese–French Oceanography Satellite

Since the launch of CFOSAT on 29 October 2018, more than three years of observational data of ocean wave spectra with a frequency range of 0.02–0.26 Hz and a horizontal resolution of 70–90 km have been obtained. This study compares wave spectra retrieved from 6°, 8°, and 10° incidence angle beams and their combination provided by CFOSAT with corresponding data from 98 buoys from the National Data Buoy Center (NDBC) in order to validate the remote sensing wave spectral accuracy from 1 January 2020 to 31 December 2022. The correlation coefficient of frequency spectra (Rs) between CFOSAT and buoys is used to represent the accuracy of the spectral form; the root mean square (RMS) of the significant wave height (SWH) is used to represent the accuracy of the total energy. The results indicate that CFOSAT can retrieve reliable wave frequency spectral forms with a high significant wave height (Rs > 0.8 when SWH > 3 m; RS < 0.4 when SWH < 1 m). The low-frequency noise in the swell part causes the main error, the RMS of the swell height is 0.4 m whereas the RMS of wind wave height is 0.24 m, and the mask filter used for spectral partitioned provided by CFOSAT can eliminate the low-frequency noise and improve the Rs of 10° beam wave spectra from 0.59 to 0.64. For the wind wave spectra, the correct spectra have been achieved and the mask filter cannot improve the accuracy. The wave spectra from the 10° beam without mask filtering provides the best estimation of total energy, the RMS of SWH is 0.23 m, after the mask filtering, the best estimation of spectral form can be achieved, the Rs is 0.64. The novelty of this study is that we found the strong correlation between SWH and Rs, where the scatter of SWH and Rs can be fitted as: Rs = 1 − exp(−0.89·SWH + 0.20); according to this approximate formula, we can estimate the reliability of wave spectra provided by CFOSAT according to the SWH in any region, which is important for wave spectral assimilation in the numerical model. The validation of wave direction indicates that the accuracy of wave spectra in the directional component is poor; further research is needed on the causes of directional errors. Generally, this study is not only an evaluation of the quality of the CFOSAT spectral data, but also an important reference for a series of research requiring the CFOSAT spectral data.

Comparison of regression analysis for estimation of initial and total fracture energy of concrete

Comparison of regression analysis for estimation of initial and total fracture energy of concrete

From Hydrometeor Size Distribution Measurements to Projections of Wind Turbine Blade Leading-Edge Erosion

Wind turbine blade leading-edge erosion (LEE) is a cause of increased operation and maintenance costs and decreased annual energy production. Thus, detailed, site-specific quantification of likely erosion conditions are critically needed to inform wind plant owner/operator decisions regarding mitigation strategies. Estimating the damage potential at a wind plant site requires accurate measurement of precipitation intensity, phase, droplet size distributions, wind speeds and their joint statistics. The current work quantifies the effect of disdrometer type on the characterization of LEE potential at a site in the US Southern Great Plains. using observations from three co-located disdrometers (an optical, an impact and a video disdrometer), along with hub-height wind-speed observations from a Doppler lidar and two LEE models: a kinetic energy model and the Springer model. Estimates of total kinetic energy of hydrometeor impacts over the four-year study period vary by as much as 38%, and coating lifetime derived from accumulated distance-to-failure estimates from the Springer model differ by an even greater amount, depending on disdrometer type. Damage potential at this site is concentrated in time, with 50% of impact kinetic energy occurring in 6–12 h per year, depending on which set of disdrometer observations is used. Rotor-speed curtailment during the most erosive 0.1–0.2% of 10 min periods is found to increase blade lifetimes and lead to the lowest levelized cost of energy.

An Integrating PV plant 689 kWp into Coal-Fired Power Plant (CFPP) 615 MW at Paiton: To reduce auxiliary load and coal consumption

Integrating solar energy into a coal-fired power plant is a promising way to reduce auxiliary load and numerous environmental issues related to the coal-based power generation sector. This paper will discuss the annual performance of PV plant 689 kWp at ash disposal that integrated into 615 MW coal-fired power plant PT xxx, including an estimate of total potential energy that can be generated; analysis of auxiliary load to improve performance and decreasing pollutant emissions by coal consumption reduction. The PV Plant has been operated for at least 2 years, built on an area of 5,000m2, is an On-grid PV Plant system with 11 grid Inverters and has 2,120 solar modules installed. Based on the simulation using Helioscope software, it can generate electrical energy up to 977,442 kWh per year with a performance ratio of 79.3%. The result of the PV plant utilization evaluation shows the amount of electrical energy produced is 1,096,105 kWh in 2021, above the estimation from the simulation. This result means auxiliary power load was decreasing by 0.4932%, It is also considered to be able to save the use of 263.065 kiloliters per year of diesel and also save the use of coal up to 386.634 tons or equivalent to 0.007% coal consumption per year. From an environmental point of view, it is also assessed to reduce CO2 emissions equivalent to 920.729 tons/year and the equivalent of planting 4,602 trees per year.

Weak Solutions to the Stationary Cahn–Hilliard/Navier–Stokes Equations for Compressible Fluids

We are concerned with the Cahn-Hilliard/Navier-Stokes equations for the stationary compressible flows in a three-dimensional bounded domain. The governing equations consist of the stationary Navier-Stokes equations describing the compressible fluid flows and the stationary Cahn-Hilliard type diffuse equation for the mass concentration difference. We prove the existence of weak solutions when the adiabatic exponent $\gamma$ satisfies $\gamma>\frac{4}{3}$. The proof is based on the weighted total energy estimates and the new techniques developed to overcome the difficulties from the capillary stress.

Gaia EDR3 Proper Motions of Milky Way Dwarfs. II Velocities, Total Energy, and Angular Momentum

Abstract Here we show that precise Gaia EDR3 proper motions have provided robust estimates of 3D velocities, angular momentum, and total energy for 40 Milky Way dwarfs. The results are statistically robust and are independent of the Milky Way mass profile. Dwarfs do not behave like long-lived satellites of the Milky Way because of their excessively large velocities, angular momenta, and total energies. Comparing them to other MW halo populations, we find that many are at first passage, ≤2 Gyr ago, i.e., more recent than the passage of Sagittarius, ∼4–5 Gyr ago. We suggest that this is in agreement with the stellar populations of all dwarfs, for which we find that a small fraction of young stars cannot be excluded. We also find that dwarf radial velocities contribute too little to their kinetic energy when compared to satellite systems with motions only regulated by gravity, and some other mechanism must be at work such as ram pressure. The latter may have preferentially reduced radial velocities when dwarf progenitors entered the halo until they lost their gas. It could also explain why most dwarfs lie near their pericenter. We also discover a novel large-scale structure perpendicular to the Milky Way disk, which is made by 20% of dwarfs orbiting or counter-orbiting with the Sagittarius dwarf.

Well-Posedness of the Second-Order SDEs Describing an N-Particle System Interacting via Coulomb Interaction

This paper concerns a second-order N interacting stochastic particle system with singular potential for any dimension n ≥ 2. By some estimates of total energy of the system, we prove that there is no collision among particles almost surely in any finite time interval, then the well-posedness of this interacting particle system can be established.

Investigation of the electronic, magnetic, elastic, thermodynamic and thermoelectric properties of Mn2CoCr Heusler compound: A DFT-based simulation

Heusler compounds have been promising materials for their applications in spintronic, memory and thermoelectric devices. The Mn2CoCr, a full Heusler compound, has been investigated here for its mechanical, thermodynamic and thermoelectric prospective for the first time using full potential linearized augmented plane wave (FP-LAPW) method in support of density functional theory (DFT). The estimation of total energy conferred to Fm-3m structure in ferromagnetic phase, which was in accordance to the others finding. The estimated total magnetic moment was found to be 5.02 (in the units of Bohr magneton), which was in accordance with the Pauling-Slater rule and available data. The electronic structure using generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) revealed its metallic nature in both the spin configurations. Further, we have calculated the thermodynamic and thermoelectric constants such as specific heat, Debye temperature, Gruneisen constant, thermal conductivity, Seebeck coefficient and power factor. Our predicted value of specific heat at constant volume is 66.6 J/mol.K at 300 K and 0 GPa, which at higher temperature (1000 K) followed Dulong-Petit limit. The power factor was calculated to be 25x1012 Wm-1K−2 at 500 K, demonstrating its suitability in thermoelectric applications.

Relation Dynamic Shear Stress and Wake Boat Waves Energy

Coastal area is the most populated throughout the world due to its business activities especially those involves commercial or recreational vessels to bring people or goods. Inadvertently, heavily vessels traffic will create effect on shoreline, riverbank or estuaries in which resulting an erosion problem. Overcoming the problem, a few local state authorities are enforcing a regulation for the vessels to cruise along the coastline to minimize the erosion impact. This research was conducted to study the relationship of dynamic shear stress generated from wake boat and tidal flow induced energy at Kemaman river estuary, which located at Kemaman province, East Coast of Peninsular Malaysia. Evidence shows that erosion occurred along the riverbank, and it was confirmed that the vessels contribute to the erosion problem due to negligence of vessels’ speed. In addition, apart from the generated energy coming from the vessel, the dimension of the vessels also contributes to the erosion problem. The estimation of total energy created by each vessel is established by a formula through the relationship with wave energy under influenced of maximum wave height. The results indicate that increases in energy will increase the dynamic shear stress due to orbital wave velocity whereby it is a function of wave height generated by boat wave. Finally, the results also indicate addition minimum tidal flow rate and wake boat contributes higher dynamic shear stress as compared to mud bed shear stress. Therefore, it can be concluded that wake boat waves play a significant role in determining the riverbank erosion. The finding of this study serves some information as guidance to local state authority to impose regulation to community whom using the vessels to navigate through this estuary.

Channel Turn-Off Energy Model for Zero-Voltage-Switching Wide Bandgap Devices

Accurate estimation of the switching loss for power MOSFETs is critical to predict the device junction temperature and the efficiency in power converters. In recent power electronics design, wide bandgap (WBG) devices are adopted with zero-voltage switching (ZVS) to achieve higher efficiency. For devices with ZVS, the only switching loss will be channel turn-off loss, and on the contrary to hard switching, the energy stored in C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">oss</sub> will be recycled. The models for the estimation of total turn-off energy have been discussed in the literature, whereas the model of channel turn-off energy is absent. In this article, a behavioral model of channel turn-off energy using a simple α- β equation for curve fitting is proposed, which can be applied to an entire current and voltage range. The proposed model is verified by different GaN HEMTs and SiC MOSFETs with a double-pulse test circuit in simulation and experiment.

Assessment of excreta collection methods to estimate true metabolizable energy of waterfowl foods in wild ducks

ABSTRACTTrue metabolizable energy (TME) of waterfowl foods is commonly estimated for use in energetic carrying capacity models in association with conservation planning efforts under the North American Waterfowl Management Plan. Researchers define and estimate TME as the net energy from excreta collected from an individual after feeding a precise quantity of a food item compared with excreta collected during a fasted control. We evaluated an alternative excreta collection method for use in TME assays for comparison with traditional excreta collection methodology for waterfowl. We fed widgeongrass (Ruppia maritima) to wild‐caught mallards (Anas platyrhynchos) during autumn 2016 at Forbes Biological Station, Havana, Illinois, USA, and quantitatively collected excreta using a harness‐style excreta collection method and a traditional basin‐style collection method. We were unable to find support for a difference in total excreta energy, mass loss, and TME estimates between collection methods, but high variation in TME among samples prohibited our ability to consider the collection methods similar. Time required for processing harness samples was 60–175 minutes less per sample than for basin samples. The basin method has been the standard for TME trials on waterfowl, but we found the harness method to be much more efficient and potentially allow for better animal husbandry practices. We suggest the harness method be tested further with increased sample sizes or alternate foods prior to widespread application, but researchers conducting TME assays of waterfowl foods should consider using this method in the future. © 2019 The Wildlife Society.

Handling missing data in an FFQ: multiple imputation and nutrient intake estimates.

We aimed to examine missing data in FFQ and to assess the effects on estimating dietary intake by comparing between multiple imputation and zero imputation. We used data from the Okazaki Japan Multi-Institutional Collaborative Cohort (J-MICC) study. A self-administered questionnaire including an FFQ was implemented at baseline (FFQ1) and 5-year follow-up (FFQ2). Missing values in FFQ2 were replaced by corresponding FFQ1 values, multiple imputation and zero imputation. A methodological sub-study of the Okazaki J-MICC study.ParticipantsOf a total of 7585 men and women aged 35-79 years at baseline, we analysed data for 5120 participants who answered all items in FFQ1 and at least 50% of items in FFQ2. Among 5120 participants, the proportion of missing data was 3·7%. The increasing number of missing food items in FFQ2 varied with personal characteristics. Missing food items not eaten often in FFQ2 were likely to represent zero intake in FFQ1. Most food items showed that the observed proportion of zero intake was likely to be similar to the probability that the missing value is zero intake. Compared with FFQ1 values, multiple imputation had smaller differences of total energy and nutrient estimates, except for alcohol, than zero imputation. Our results indicate that missing values due to zero intake, namely missing not at random, in FFQ can be predicted reasonably well from observed data. Multiple imputation performed better than zero imputation for most nutrients and may be applied to FFQ data when missing is low.

Energy Requirements for Biomass Harvest and Densification

This research quantified the unit and bulk density of several biomass crops across a variety of harvest and processing methods, as well as the energy and fuel requirements for these operations. A load density of approximately 240 kg·m−3 is needed to reach the legal weight limit of most transporters. Of the three types of balers studied, only the high density (HD) large square baler achieved this target density. However, the specific energy and fuel requirements increased exponentially with bale density, and at the maximum densities for corn stover and switchgrass, the dry basis energy and fuel requirements ranged from 4.0 to 5.0 kW·h·Mg−1 and 1.2 to 1.4 L·Mg−1, respectively. Throughputs of tub grinders when grinding bales was less than any other harvesting or processing methods investigated, so specific energy and fuel requirements were high and ranged from 13 to 32 kW·h·Mg−1 and 5.0 to 11.3 L·Mg−1, respectively. Gross size-reduction by pre-cutting at baling increased bale density by less than 6% and increased baling energy requirements by 11% to 22%, but pre-cut bales increased the tub grinder throughput by 25% to 45% and reduced specific fuel consumption for grinding by 20% to 53%. Given the improvement in tub grinder operation, pre-cutting bales should be considered as a means to increase grinder throughput. Additional research is needed to determine the energy required to grind high density pre-cut bales at high throughputs so that better estimates of total energy required for a high density bale system can be made. An alternative bulk feedstock system was investigated that involved chopping moist biomass crops with a precision-cut forage harvester, compacting the bulk material in a silo bag, and then segmenting the densified material into modules optimized for efficient transport. The specific fuel use for chopping and then compacting biomass crops in the silo bag ranged from 1.6 to 3.0 L·Mg−1 and 0.5 to 1.3 L·Mg−1, respectively. At the proposed moistures, the compacted density in the silo bags was sufficient to achieve weight-limited transport although there would be less dry matter (DM) shipped than with the high density dry bale system. Additional development work is needed to create transportable modules from the compacted silo bag. The overall results of this research will allow more accurate estimates of biomass logistics costs based on product density and energy expenditures.

Configurational Energies of Nanoparticles Based on Metal–Metal Coordination

Nanoparticle sintering remains a fundamental problem in heterogeneous catalysis, motivating mechanistic studies toward mitigating deactivation of precious metal catalysts. We present a model based on the local coordination environment of metal atoms that can be used to provide total energy estimates for metal nanoparticles in a space of generic configurations. All energies are based only on a small set of density functional theory calculations of single metal atom adsorption on metal slabs. A model that can provide accurate nanoparticle energies is an important step toward the goal of understanding their sintering behavior in practical catalytic contexts.

Nutritional adequacy of dietary intake in women with anorexia nervosa.

Understanding nutrient intake of anorexia nervosa (AN) patients is essential for the treatment. Therefore, estimates of total energy and nutrient consumption were made in a group of young women (19 to 30 years) with restricting and binge purge subtypes of AN participating in an ecological momentary assessment study. Participants completed three nonconsecutive 24-hour diet recalls. Mean nutrient intakes were stratified by subtype and by quartiles of energy intake and compared to the age specific Dietary Reference Intake (DRI) levels, as well as to the reported intakes from the What We Eat In America (WWEIA) dietary survey 2011–2012. Reported intake was determined for energy, macronutrients, and micronutrients. The mean body mass index (BMI) for all participants was 17.2 ± 0.1 kg/m2. Reported nutrient intake was insufficient for participants in quartiles 1–3 of both AN subtypes when compared to the DRIs. Intake reported by participants in quartile 4 of both subgroups met requirements for most nutrients and even met or exceeded estimated energy needs. Counseling of AN patients should be directed to total food consumption to improve energy intake and to reduce individual nutritional gaps.

Modeling shock waves generated by explosive volcanic eruptions

Atmospheric shock waves induced by explosive volcanic eruptions can provide valuable information about eruption characteristics. Shock waves are manifested as pressure‐density gradients that can be remotely observed with relatively little noise. Field measurements of expanding shock waves can be directly recorded by pressure transducers or imaged under the proper illumination and atmospheric conditions. In this paper, an open‐ended shock tube was used to generate weak shock waves in the laboratory that are representative of explosive volcanic eruptions. They indicate that strong shock wave theory can be used for modeling moderate volcanic eruptions. Based on that finding, we use strong shock theory to estimate the sudden explosive energy released from several explosive eruptions. Our energy calculations are well correlated with total energy estimates derived from plume height or erupted mass.