Journal articles: 'Mass and energy balance analysis'

1

Hock, Regine, Valentina Radić, and Mattias De Woul. "Climate sensitivity of Storglaciären, Sweden: an intercomparison of mass-balance models using ERA-40 re-analysis and regional climate model data." Annals of Glaciology 46 (2007): 342–48. http://dx.doi.org/10.3189/172756407782871503.

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AbstractEstimates of glacier contributions to future sea-level rise are often computed from mass-balance sensitivities derived for a set of representative glaciers. Our purpose is to investigate how mass-balance projections and sensitivities vary when using different approaches to compute the glacier mass balance. We choose Storglaciären, Sweden, as a test site and apply five different models including temperature-index and energy-balance approaches further varying in spatial discretization. The models are calibrated using daily European Centre for Medium-Range Weather Forecasts re-analysis (ERA-40) data. We compute static mass-balance sensitivities and cumulative mass balances until 2100 based on daily temperatures predicted by a regional climate model. Net mass-balance sensitivities to a +1 K perturbation and a 10% increase in precipitation spanned from –0.41 to –0.61 and from 0.19 to 0.22ma–1, respectively. The cumulative mass balance for the period 2002–2100 in response to the climate-model predicted temperature changes varied between –81 and –92m for four models, but was –121m for the fully distributed detailed energy-balance model. This indicates that mass losses may be underestimated if temperature-index methods are used instead of detailed energy-balance approaches that account for the effects of temperature changes on all energy-balance components individually. Our results suggest that future glacier predictions are sensitive to the choice of the mass-balance model broadening the spectrum in uncertainties.

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Sukhov, Vitalіy, and Yaroslav Kozei. "Analysis of mass-energy balance of unmanned aircraft fueled by solar energy." Eastern-European Journal of Enterprise Technologies 3, no. 9 (87) (June 15, 2017): 10–18. http://dx.doi.org/10.15587/1729-4061.2017.101974.

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Pan, Jae Gu, and Joon Shick Rhee. "Mass and energy balance for analysis of oleaginous yeast growth." Korean Journal of Chemical Engineering 2, no. 1 (March 1985): 81–85. http://dx.doi.org/10.1007/bf02697554.

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Clark, W. D., W. R. Seeker, and C. C. Lee. "Engineering analysis of hazardous waste incineration energy and mass balance." Nuclear and Chemical Waste Management 7, no. 1 (1987): 21–28. http://dx.doi.org/10.1016/0191-815x(87)90038-6.

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Oǧkuztöreli, M. N., A. Chambers, and B. Özüm. "Analysis of mass and energy balance equations in gas-solid reactions." Canadian Journal of Chemical Engineering 66, no. 5 (October 1988): 767–75. http://dx.doi.org/10.1002/cjce.5450660510.

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Machguth, Horst, Wilfried Haeberli, and Frank Paul. "Mass-balance parameters derived from a synthetic network of mass-balance glaciers." Journal of Glaciology 58, no. 211 (2012): 965–79. http://dx.doi.org/10.3189/2012jog11j223.

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AbstractGlacier mass-balance parameters such as the equilibrium-line altitude (ELA) play an important role when working with large glacier samples. While the number of observational mass-balance series to derive such parameters is limited, more and more modeled data are becoming available.Here we explore the possibilities of analyzing such 'synthetic' mass-balance data with respect to mass-balance parameters. A simplified energy-balance model is driven by bias-corrected regional climate model output to model mass-balance distributions for 94 glaciers in the Swiss Alps over 15 years. The modeling results in realistic interannual variability and mean cumulative mass balance. Subsequently model output is analyzed with respect to 18 topographic and mass-balance parameters and a correlation analysis is performed. Well-known correlations such as for ELA and median elevation are confirmed from the synthetic data. Furthermore, previously unreported parameter relationships are found such as a correlation of the balance rate at the tongue with the accumulation-area ratio (AAR) and of the glacier elevation range with the AAR. Analyzing modeled data complements in situ observations and highlights their importance: the small number of accurate mass-balance observations available for validation is a major challenge for the presented approach.

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Chern, S. M., Walter P. Walawender, and L. T. Fan. "Mass and energy balance analyses of a downdraft gasifier." Biomass 18, no. 2 (January 1989): 127–51. http://dx.doi.org/10.1016/0144-4565(89)90089-9.

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Medica-Viola, Vedran, Sandi Baressi Šegota, Vedran Mrzljak, and Daniel Štifanić. "Comparison of conventional and heat balance based energy analyses of steam turbine." Pomorstvo 34, no. 1 (June 30, 2020): 74–85. http://dx.doi.org/10.31217/p.34.1.9.

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This paper presents a comparison of conventional and heat balance based energy analyses of steam turbine. Both analyses are compared by using measured operating parameters from low power steam turbine exploitation. The major disadvantage of conventional steam turbine energy analysis is that extracted energy flow streams are not equal in real (polytropic) and ideal (isentropic) expansion processes, while the heat balance based energy analysis successfully resolved mentioned problem. Heat balance based energy analysis require an increase of steam mass flow rates extracted from the turbine in ideal (isentropic) expansion process to ensure always the same energy flow streams to all steam consumers. Increase in steam mass flow rate extracted through each turbine extraction (heat balance based energy analysis) result with a decrease in energy power losses and with an increase in energy efficiency of whole turbine and all of its cylinders (when compared to conventional analysis). All of the obtained conclusions in this research are valid not only for the analyzed low power steam turbine, but also for any other steam turbine with steam extractions.

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Bradley, David P., Roger Kulstad, Natalie Racine, Yoram Shenker, Melissa Meredith, and Dale A. Schoeller. "Alterations in energy balance following exenatide administration." Applied Physiology, Nutrition, and Metabolism 37, no. 5 (October 2012): 893–99. http://dx.doi.org/10.1139/h2012-068.

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Exenatide is a medication similar in structure and effect to native glucagon-like peptide-1, an incretin hormone with glucose-lowering properties. The aim of the study was to measure the change in total energy expenditure (TEE) and body composition during exenatide administration and by deduction the relative contributions of energy expenditure and energy intake to exenatide-induced weight loss. Forty-five obese (body mass index, 30–40 kg·m–2) subjects were identified. After exclusion criteria application, 28 subjects entered into the study and 18 subjects (12 female, 6 male) completed the study, which consisted of 6 visits over 14 weeks and injection of exenatide for an average of 84 ± 5 days. Respiratory gas analysis and doubly labeled water measurements were performed before initiation of exenatide and after approximately 3 months of exenatide administration. The average weight loss from the beginning of injection period to the end of the study in completed subjects was 2.0 ± 2.8 kg (p = 0.01). Fat mass declined by 1.3 ± 1.8 kg (p = 0.01) while the fat-free mass trended downward but was not significant (0.8 ± 2.2 kg, p = 0.14). There was no change in weight-adjusted TEE (p = 0.20), resting metabolic rate (p = 0.51), or physical activity energy expenditure (p = 0.38) and no change in the unadjusted thermic effect of a meal (p = 0.37). The significant weight loss because of exenatide administration was thus the result of decreasing energy intake. In obese nondiabetic subjects, exenatide administration did not increase TEE and by deduction the significant weight loss and loss of fat mass was due to decreased energy intake.

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Huintjes, Eva, Niklas Neckel, Volker Hochschild, and Christoph Schneider. "Surface energy and mass balance at Purogangri ice cap, central Tibetan Plateau, 2001–2011." Journal of Glaciology 61, no. 230 (2015): 1048–60. http://dx.doi.org/10.3189/2015jog15j056.

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AbstractMost glaciers on the Tibetan Plateau are difficult to assess as they are located in remote regions at high altitude. This study focuses on the surface energy-balance (SEB) and mass-balance (MB) characteristics of Purogangri ice cap (PIC). A ‘COupled Snowpack and Ice surface energy and MAss balance model’ (COSIMA) is applied without observational data from the ground. The model is forced by a meteorological dataset from the High Asia Refined analysis. Model results for annual surface-elevation changes and MB agree well with the results of a previous remote-sensing estimate. Low surface velocities of 0.026 ± 0.012 m d−1 were measured by repeat-pass InSAR. This finding supports the validation of the steady-state COSIMA against satellite-derived surface changes. Overall MB of PIC for the period 2001–11 is nearly balanced (−44 kg m−2 a−1). Analysis of the model-derived SEB/MB components reveals that a significant amount of snowfall in spring is responsible for high surface albedo throughout the year. Thus, the average surface energy loss through net longwave radiation is larger than the energy gain through net shortwave radiation. The dry continental climate favours mass loss through sublimation, which accounts for 66% of the total mass loss.

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Jemaa, N., R. D. Noble, and C. A. Koval. "Combined mass and energy balance analysis of an electrochemically modulated equilibrium stage process." Chemical Engineering Science 47, no. 6 (1992): 1469–79. http://dx.doi.org/10.1016/0009-2509(92)80292-k.

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12

Thakur, Vikas Kumar. "A Study on Heat and Mass Transfer Analysis of Solar Still." International Journal of Engineering Research in Mechanical and Civil Engineering (IJERMCE) 9, no. 5 (May 18, 2022): 11–16. http://dx.doi.org/10.36647/ijermce/09.05.a003.

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To evaluate the performance of solar still, it is very important to know about the energy balance and heat transfer. Heat transfer phenomena occur inside the still through three variable modes convection, evaporation, and radiation. As the temperature of water increases, the evaporation rate also increases. Therefore, many modifications have been done to increase the evaporation rate of basin water by the researchers, such as using nanoparticles, photovoltaic module, flat plate collector, heat exchangers, and phase change materials etc. The heat and mass transfer study on different parts of SS along with energy balance is presented in the paper. The reader will get information about the quantity of heat absorbed and the heat released inside the basin. Modification made on SS to increase productivity in the last 4-5 years has also been presented. The study found that the productivity of modified solar still gives 53.95% higher than the conventional solar still after adding external devices and energy storage

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13

Machguth, Horst, Frank Paul, Martin Hoelzle, and Wilfried Haeberli. "Distributed glacier mass-balance modelling as an important component of modern multi-level glacier monitoring." Annals of Glaciology 43 (2006): 335–43. http://dx.doi.org/10.3189/172756406781812285.

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AbstractModern concepts of worldwide glacier monitoring include numerical models for (1) interconnecting the different levels of observations (local mass balance, representative length change, glacier inventories for global coverage) and (2) extrapolations in space (coupling with climate models) and time (backward and forward). In this context, one important new tool is distributed mass-balance modelling in complex mountain topography. This approach builds on simplified energy-balance models and can be applied for investigating the spatio-temporal representativity of the few mass-balance measurements, for estimating balance values at the tongue of unmeasured glaciers in order to derive long-term average balance values from a great number of glaciers with known length change, and for assessing special effects such as the influence of Sahara dust falls on the albedo and mass balance or autocorrelation effects due to surface darkening of glaciers with strongly negative balances. Experience from first model runs in the Swiss Alps and from applications to the extreme conditions in summer 2003 provides evidence about the usefulness of this approach for glacier monitoring and analysis of glacier changes in high-mountain regions. The main difficulties concern the spatial variability of the input parameters (e.g. precipitation, snow cover and surface albedo) and the uncertainties in the parameterizations of the components of the energy balance. Field measurements remain essential to tie the models to real ground conditions.

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Pei, Haipeng, Baosheng Jin, and Yaji Huang. "Quantitative analysis of mass and energy flow in rice straw gasification based on mass and carbon balance." Renewable Energy 161 (December 2020): 846–57. http://dx.doi.org/10.1016/j.renene.2020.08.014.

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Ohol, Sandeep, Mathew VK, Savita Shinde, and G. Balachandran. "Heat balance analysis in electric arc furnace for process improvement." E3S Web of Conferences 170 (2020): 02012. http://dx.doi.org/10.1051/e3sconf/202017002012.

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The current study deals with optimizing the melting process used in electric arc furnace by heat balance equations. Heat balance is a very important aspect in an arc furnace in which the energy input consists of electrical energy [65%], chemical energy [25%] and exothermic reaction heat [10%]. This energy is optimized with the charge mix, charge quantity, fluxes, fuel used, and O2 used in the burners. The present model considers all these aspects and gives heat distribution in the process. The model spreadsheet gives a reasonable prediction in terms of metal yield, composition, and energy consumption. The model also predicts the amount of iron oxidized in the process. The mass and heat balance model is a useful tool for process analysis and improves the process efficiency of electric arc furnace steelmaking.

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16

Azam, M. F., P. Wagnon, C. Vincent, AL Ramanathan, A. Mandal, and J. G. Pottakkal. "Processes governing the mass balance of Chhota Shigri Glacier (Western Himalaya, India) assessed by point-scale surface energy balance measurements." Cryosphere Discussions 8, no. 3 (June 5, 2014): 2867–922. http://dx.doi.org/10.5194/tcd-8-2867-2014.

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Abstract. Recent studies revealed that Himalayan glaciers have been shrinking at an accelerated rate since the beginning of the 21st century. However the climatic causes for this shrinkage remain unclear given that surface energy balance studies are almost nonexistent in this region. In this study, a point-scale surface energy balance analysis was performed using in-situ meteorological data from the ablation zone of Chhota Shigri Glacier over two separate periods (August 2012 to February 2013 and July to October 2013) in order to understand the response of mass balance to climate change. Energy balance numerical modeling provides quantification of the surface energy fluxes and identification of the factors affecting glacier mass balance. The computed ablation was validated by stake observations. During summer-monsoon period, net radiation was the primary component of the surface energy balance with 82% of the total heat flux which was complimented with turbulent sensible and latent heat fluxes with a share of 13% and 5%, respectively. A striking feature of energy balance is the positive turbulent latent heat flux, thus condensation or re-sublimation of moist air at the glacier surface takes place, during summer-monsoon period which is characterized by relatively high air temperature, high relative humidity and almost permanent melting surface. The impact of Indian summer monsoon on Chhota Shigri Glacier mass balance has also been assessed. This analysis demonstrates that the intensity of snowfall events during the summer-monsoon season plays a key role on surface albedo, in turn on melting, and thus is among the most important drivers controlling the annual mass balance of the glacier. Summer-monsoon air temperature, controlling the precipitation phase (rain vs. snow and thus albedo), counts, indirectly, also among the most important drivers for the glacier mass balance.

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17

Westerterp, K. R., B. Kayser, L. Wouters, J. L. Le Trong, and J. P. Richalet. "Energy balance at high altitude of 6,542 m." Journal of Applied Physiology 77, no. 2 (August 1, 1994): 862–66. http://dx.doi.org/10.1152/jappl.1994.77.2.862.

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Weight loss due to malnutrition and possibly intestinal malabsorption is a well-known phenomenon in high-altitude climbers. Up to approximately 5,000 m, energy balance may be attained and intestinal energy digestibility remains normal. To see whether 1) energy balance may also be attained at 6,542 m and, if not, 2) whether decreased energy digestibility would play a significant role in the energy deficit, energy intake (EI), energy expenditure, body composition, and energy digestibility of 10 subjects (4 women, 6 men; 27–44 yr) were assessed during a 21-day sojourn on the summit of Mt. Sajama, Bolivia (6,542 m). EI was measured during two 3-day intervals: EI1 (days 7–9) and EI2 (days 17–19). Total fecal energy loss during EI1 was calculated from fecal energy measured by bomb calorimetry. Average daily metabolic rate (ADMR) at altitude was measured in six subjects (2 women, 4 men) using doubly labeled water over a 10-day interval (days 9–19). Basal metabolic rate was measured before and after the expedition by respiratory gas analysis. Body composition was estimated from skinfolds and body mass before and during the altitude sojourn. Subjects were in negative energy balance throughout the observation period (EI1-ADMR = -2.9 +/- 1.8 MJ/day and EI2-ADMR = -2.3 +/- 1.8 MJ/day based on a gross energy digestibility of 95%). The activity level, expressed as ADMR to basal metabolic rate, was 1.56–2.39. The loss of fat mass (3.7 +/- 1.5 kg) represented 74 +/- 15% of the loss of body mass.(ABSTRACT TRUNCATED AT 250 WORDS)

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Gabbi, J., M. Huss, A. Bauder, F. Cao, and M. Schwikowski. "The impact of Saharan dust and black carbon on albedo and long-term mass balance of an Alpine glacier." Cryosphere 9, no. 4 (July 30, 2015): 1385–400. http://dx.doi.org/10.5194/tc-9-1385-2015.

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Abstract. Light-absorbing impurities in snow and ice control glacier melt as shortwave radiation represents the main component of the surface energy balance. Here, we investigate the long-term effect of snow impurities, i.e., mineral dust and black carbon (BC), on albedo and glacier mass balance. The analysis was performed over the period 1914–2014 for two sites on Claridenfirn, Swiss Alps, where an outstanding 100-year record of seasonal mass balance measurements is available. Information on atmospheric deposition of mineral dust and BC over the last century was retrieved from two firn/ice cores of high-alpine sites. A combined mass balance and snow/firn layer model was employed to assess the effects of melt and accumulation processes on the impurity concentration at the surface and thus on albedo and glacier mass balance. Compared to pure snow conditions, the presence of Saharan dust and BC lowered the mean annual albedo by 0.04–0.06 depending on the location on the glacier. Consequently, annual melt was increased by 15–19 %, and the mean annual mass balance was reduced by about 280–490 mm w.e. BC clearly dominated absorption which is about 3 times higher than that of mineral dust. The upper site has experienced mainly positive mass balances and impurity layers were continuously buried whereas at the lower site, surface albedo was more strongly influenced by re-exposure of dust and BC-enriched layers due to frequent years with negative mass balances.

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Barbagallo, Salvatore, Simona Consoli, and Alfonso Russo. "SURFACE ENERGY BALANCE OVER ORANGE ORCHARD USING SURFACE RENEWAL ANALYSIS." Journal of Agricultural Engineering 40, no. 4 (December 31, 2009): 39. http://dx.doi.org/10.4081/jae.2009.89.

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Reliable estimation of surface sensible and latent heat flux is the most important process to appraise energy and mass exchange among atmosphere and biosphere. In this study the surface energy fluxes were measured over an irrigated orange orchard during 2005-2008 monitoring periods using a Surface Renewal- Energy Balance approach. The experimental area is located in a representative orchard growing area of eastern Sicily (Italy). The performance of Surface Renewal (SR) analysis for estimating sensible heat flux (H) was analysed and evaluated in terms of correlation with H fluxes from the eddy covariance (EC) method. Study revealed that the mean available energy (RN- G) and latent heat flux (LE) were of about 300 W m-2 and 237 W m-2, respectively, during dry periods and unstable-case atmospheric conditions. The estimated crop coefficient Kc values for the orchard crop averaged close to 0.80, which is considerably higher than previous FAO studies that found the value to be 0.65 for citrus with 70% of ground cover. The intercepted photosynthetically active radiation (LI PAR) by the crop was measured and relationships between LAI and crop coefficient (Kc) were established.

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Kaplan, A. F. H., and G. Groboth. "Process Analysis of Laser Beam Cladding." Journal of Manufacturing Science and Engineering 123, no. 4 (April 1, 2000): 609–14. http://dx.doi.org/10.1115/1.1344899.

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The technology of laser beam cladding of metals by single-step powder delivery is analyzed with a process model which is based on balance equations of energy and mass. Effects like powder heating, clad layer formation, substrate dilution and overlapping of tracks are discussed in dependence of the process parameters. In particular, the powder catchment efficiency and the beam energy redistribution in the material can be optimized by the powder mass flow rate and by the geometrical properties of the beam and of the powder jet.

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Harto, Andang W., and Mella Soelanda. "Mass and Energy Balance Analysis of Methanol Production Using Atmospheric CO2 Capture with Energy Source from PCMSR." E3S Web of Conferences 42 (2018): 01004. http://dx.doi.org/10.1051/e3sconf/20184201004.

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The rising of atmospheric CO2 concentration is the major source to global warming system. Many methods have been proposed to mitigate global warming, such as carbon penalty, carbon trading, CO2 sequestration, etc. However these proposed methods are usually uneconomical, i.e., these methods do not produce economic valuable substances. This paper will propose a method to absorb atmospheric CO2 to produce economic valuable substances such as methanol, dimethyl ether, ethylene, several hydrocarbon substances and derivatives and several graphite substances. This paper is focused on methanol production using atmospheric CO2 capture. The overall process is endothermic. Thus a sufficient energy source is needed. To avoid more CO2 emission, the energy source must not use conventional fuels. To assure the continuity of energy deliberation, nuclear energy will be used as the energy source of the process. In this paper, the Passive Compact Molten Salt Reactor (PCMSR) will be used as the energy source. The 460 MWth PCMSR is coupled with atmospheric CO2 capture, desalination, hydrogen production and methanol production facilities. The capturing CO2 capacity is 7.2 ton/h of atmospheric CO2. The valuable outputs of this system are 3.34 ton/h of H2, 34.56 ton/h of O2, 5.24 ton/h of methanol and 86.74 MWe of excess electricity.

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Peltola, Petteri, Tero Tynjälä, Jouni Ritvanen, and Timo Hyppänen. "Mass, energy, and exergy balance analysis of chemical looping with oxygen uncoupling (CLOU) process." Energy Conversion and Management 87 (November 2014): 483–94. http://dx.doi.org/10.1016/j.enconman.2014.07.044.

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Kapsch, Marie-Luise, Uwe Mikolajewicz, Florian A. Ziemen, Christian B. Rodehacke, and Clemens Schannwell. "Analysis of the surface mass balance for deglacial climate simulations." Cryosphere 15, no. 2 (March 3, 2021): 1131–56. http://dx.doi.org/10.5194/tc-15-1131-2021.

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Abstract. A realistic simulation of the surface mass balance (SMB) is essential for simulating past and future ice-sheet changes. As most state-of-the-art Earth system models (ESMs) are not capable of realistically representing processes determining the SMB, most studies of the SMB are limited to observations and regional climate models and cover the last century and near future only. Using transient simulations with the Max Planck Institute ESM in combination with an energy balance model (EBM), we extend previous research and study changes in the SMB and equilibrium line altitude (ELA) for the Northern Hemisphere ice sheets throughout the last deglaciation. The EBM is used to calculate and downscale the SMB onto a higher spatial resolution than the native ESM grid and allows for the resolution of SMB variations due to topographic gradients not resolved by the ESM. An evaluation for historical climate conditions (1980–2010) shows that derived SMBs compare well with SMBs from regional modeling. Throughout the deglaciation, changes in insolation dominate the Greenland SMB. The increase in insolation and associated warming early in the deglaciation result in an ELA and SMB increase. The SMB increase is caused by compensating effects of melt and accumulation: the warming of the atmosphere leads to an increase in melt at low elevations along the ice-sheet margins, while it results in an increase in accumulation at higher levels as a warmer atmosphere precipitates more. After 13 ka, the increase in melt begins to dominate, and the SMB decreases. The decline in Northern Hemisphere summer insolation after 9 ka leads to an increasing SMB and decreasing ELA. Superimposed on these long-term changes are centennial-scale episodes of abrupt SMB and ELA decreases related to slowdowns of the Atlantic meridional overturning circulation (AMOC) that lead to a cooling over most of the Northern Hemisphere.

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Azam, M. F., P. Wagnon, C. Vincent, AL Ramanathan, V. Favier, A. Mandal, and J. G. Pottakkal. "Processes governing the mass balance of Chhota Shigri Glacier (western Himalaya, India) assessed by point-scale surface energy balance measurements." Cryosphere 8, no. 6 (November 27, 2014): 2195–217. http://dx.doi.org/10.5194/tc-8-2195-2014.

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Abstract. Some recent studies revealed that Himalayan glaciers were shrinking at an accelerated rate since the beginning of the 21st century. However, the climatic causes for this shrinkage remain unclear given that surface energy balance studies are almost nonexistent in this region. In this study, a point-scale surface energy balance analysis was performed using in situ meteorological data from the ablation zone of Chhota Shigri Glacier over two separate periods (August 2012 to February 2013 and July to October 2013) in order to understand the response of mass balance to climatic variables. Energy balance numerical modelling provides quantification of the surface energy fluxes and identification of the factors affecting glacier mass balance. The model was validated by comparing the computed and observed ablation and surface temperature data. During the summer-monsoon period, net radiation was the primary component of the surface energy balance accounting for 80 % of the total heat flux followed by turbulent sensible (13%), latent (5%) and conductive (2%) heat fluxes. A striking feature of the energy balance is the positive turbulent latent heat flux, suggesting re-sublimation of moist air at the glacier surface, during the summer-monsoon characterized by relatively high air temperature, high relative humidity and a continual melting surface. The impact of the Indian Summer Monsoon on Chhota Shigri Glacier mass balance has also been assessed. This analysis demonstrates that the intensity of snowfall events during the summer-monsoon plays a key role on surface albedo (melting is reduced in the case of strong snowfalls covering the glacier area), and thus is among the most important drivers controlling the annual mass balance of the glacier. The summer-monsoon air temperature, controlling the precipitation phase (rain versus snow and thus albedo), counts, indirectly, also among the most important drivers.

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Gabbi, J., M. Huss, A. Bauder, F. Cao, and M. Schwikowski. "The impact of Saharan dust and black carbon on albedo and long-term glacier mass balance." Cryosphere Discussions 9, no. 1 (February 24, 2015): 1133–75. http://dx.doi.org/10.5194/tcd-9-1133-2015.

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Abstract. Light-absorbing impurities in snow and ice control glacier melt as shortwave radiation represents the main component of the surface energy balance. Here, we investigate the long-term effect of snow impurities, i.e. Saharan dust and black carbon (BC), on albedo and glacier mass balance. The analysis was performed over the period 1914–2014 for two sites on Claridenfirn, Swiss Alps, where an outstanding 100 year record of seasonal mass balance measurements is available. Information on atmospheric deposition of mineral dust and BC over the last century was retrieved from two firn/ice cores of high-alpine sites. A combined mass balance and snow/firn layer model was employed to assess the dust/BC-albedo feedback. Compared to pure snow conditions, the presence of Saharan dust and BC lowered the mean annual albedo by 0.04–0.06 and increased melt by 15–19% on average depending on the location on the glacier. BC clearly dominated absorption which is about three times higher than that of mineral dust. The upper site has experienced mainly positive mass balances and impurity layers were continuously buried whereas at the lower site, surface albedo was more strongly influenced by re-exposure of dust-enriched layers due to frequent years with negative mass balances.

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Sun, Z. F., and C. G. Carrington. "Application of Nonequilibrium Thermodynamics in Second Law Analysis." Journal of Energy Resources Technology 113, no. 1 (March 1, 1991): 33–39. http://dx.doi.org/10.1115/1.2905777.

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We examine the exergy balance of a multi-component fluid subject to viscous dissipation processes, heat transfer by conduction, heat transfer by radiation, matter diffusion and chemical reactions. The differential equations for exergy balance in the fluid formalize the relationship between the exergy input/output approach to second law analysis and the entropy generation procedure using the Gouy-Stodola theorem. The balance relations for mass, momentum, energy and entropy are used to establish the validity conditions for the exergy balance equations. In particular, we define the role and significance of the assumption of local thermodynamic equilibrium. The general functions and restrictions of nonequilibrium thermodynamics within second law analysis are also discussed.

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Rouboa, Abel, Valter Silva, and Nuno Couto. "Exergy Analysis in Hydrogen-Air Detonation." Journal of Applied Mathematics 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/502979.

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The main goal of this paper is to analyze the exergy losses during the shock and rarefaction wave of hydrogen-air mixture. First, detonation parameters (pressure, temperature, density, and species mass fraction) are calculated for three cases where the hydrogen mass fraction in air is 1.5%, 2.5%, and 5%. Then, exergy efficiency is used as objective criteria of performance evaluation. A two-dimensional computational fluid dynamic code is developed using Finite volume discretization method coupled with implicit scheme for the time discretization (Euler system equations). A seven-species and five-step global reactions mechanism is used. Implicit total variation diminishing (TVD) algorithm, based on Riemann solver, is solved. The typical diagrams of exergy balances of hydrogen detonation in air are calculated for each case. The energy balance shows a successive conversion of kinetic energy, and total enthalpy, however, does not indicate consequent losses. On the other hand, exergy losses increase with the augment of hydrogen concentration in air. It obtained an exergetic efficiency of 77.2%, 73.4% and 69.7% for the hydrogen concentrations of 1.5%, 2.5%, and 5%, respectively.

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Klok, E. J., M. Nolan, and M. R. Van Den Broeke. "Analysis of meteorological data and the surface energy balance of McCall Glacier, Alaska, USA." Journal of Glaciology 51, no. 174 (2005): 451–61. http://dx.doi.org/10.3189/172756505781829241.

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AbstractWe report on analysis of meteorological data for the period 27 May–20 August 2004, from two automatic weather stations on McCall Glacier, Alaska, USA, aimed at studying the relationship between climate and ablation. One station is located on a mountain ridge and the other in the ablation area where we also analyzed the energy balance. The weather station on the glacier measured an average temperature of 5.3°C (at 2 m height above surface) and wind speed of 3.1 m s−1 (at 3 m height). A sonic height ranger and ablation stakes indicate a specific mass balance of –1.94 ± 0.09 m w.e between 15 June and 20 August. The specific mass balance calculated from the surface energy balance, –2.06 ± 0.18 m w.e., is in close correspondence to this. The latter is the sum of 0.12 m w.e. of snowfall, 0.003 m w.e. of deposition and –2.18 m w.e. of melt. Net radiation contributes 74% of the melt energy. Compared to ablation measurements in the early 1970s, summer ablation was large. This increase is explained by a combination of a relatively higher net radiation, a lower albedo and larger turbulent heat fluxes that led to more energy being available for melting. No single meteorological variable can be isolated as being the principal reason for the high ablation, however. The lower ice albedo (0.19) is possibly due to ash deposits from forest fires.

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Gavrisheva, A. I., B. F. Belokopytov, V. I. Semina, E. S. Shastik, T. V. Laurinavichene, and A. A. Tsygankov. "Mass-energy balance analysis for estimation of light energy conversion in an integrated system of biological H2 production." Biofuel Research Journal 2, no. 4 (December 1, 2015): 324–30. http://dx.doi.org/10.18331/brj2015.2.4.7.

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Mott, Rebecca, Andreas Wolf, Maximilian Kehl, Harald Kunstmann, Michael Warscher, and Thomas Grünewald. "Avalanches and micrometeorology driving mass and energy balance of the lowest perennial ice field of the Alps: a case study." Cryosphere 13, no. 4 (April 15, 2019): 1247–65. http://dx.doi.org/10.5194/tc-13-1247-2019.

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Abstract. The mass balance of very small glaciers is often governed by anomalous snow accumulation, winter precipitation being multiplied by snow redistribution processes (gravitationally or wind driven), or suppressed snow ablation driven by micrometeorological effects lowering net radiation and/or turbulent heat exchange. In this case study, we analysed the relative contribution of snow accumulation and ablation processes governing the long- and short-term mass balance of the lowest perennial ice field of the Alps, the Ice Chapel, located at 870 m a.s.l. in the Berchtesgaden National Park (Germany). This study emphasizes the importance of the local topographic setting for the survival of a perennial ice field located far below the climatic snow line. Although long-term mass balance measurements of the ice field surface showed a dramatic mass loss between 1973 and 2014, the ice field mass balance was rather stable between 2014 and 2017 and even showed a strong mass gain in 2017/2018 with an increase in surface height by 50 %–100 % relative to the ice field thickness. Measurements suggest that the winter mass balance clearly dominated the annual mass balance. At the Ice Chapel surface, 92 % of snow accumulation was gained by snow avalanching, thus clearly governing the 2017/2018 winter mass balance of the ice field with mean snow depths of 32 m at the end of the accumulation period. Avalanche deposition was amplified by preferential deposition of snowfall in the wind-sheltered rock face surrounding the ice field. Detailed micrometeorological measurements combined with a numerical analysis of the small-scale near-surface atmospheric flow field identified the micrometeorological processes driving the energy balance of the ice field. Measurements revealed a katabatic flow system draining down the ice field throughout the day, showing strong temporal and spatial dynamics. The spatial origin of the thermal flow system was shown to be of particular importance for the ice field surface energy balance. Numerical simulation indicates that deep katabatic flows, which developed at higher-elevation shaded areas of the rock face and drained down the ice field, enhance sensible heat exchange towards the ice field surface by enhancing turbulence close to the ice surface. Conversely, the shallow katabatic flow developing at the ice field surface appeared to laterally decouple the local near-surface atmosphere from the warmer adjacent air suppressing heat exchange. Numerical results thus suggest that shallow katabatic flows driven by the cooling effect of the ice field surface are especially efficient in lowering the climatic sensitivity of the ice field to the surrounding rising air temperatures. Such micrometeorological phenomena must be taken into account when calculating mass and energy balances of very small glaciers or perennial ice fields at elevations far below the climatic snow line.

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Shi, Xiaogang, Matthew Sturm, Glen E. Liston, Rachel E. Jordan, and Dennis P. Lettenmaier. "SnowSTAR2002 Transect Reconstruction Using a Multilayered Energy and Mass Balance Snow Model." Journal of Hydrometeorology 10, no. 5 (October 1, 2009): 1151–67. http://dx.doi.org/10.1175/2009jhm1098.1.

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Abstract The lateral and vertical variability of snow stratigraphy was investigated through the comparison of the measured profiles of snow density, temperature, and grain size obtained during the Snow Science Traverse—Alaska Region (SnowSTAR2002) 1200-km transect from Nome to Barrow with model reconstructions from the Snow Thermal Model (SNTHERM), a multilayered energy and mass balance snow model. Model profiles were simulated at the SnowSTAR2002 observation sites using the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) as meteorological forcing. ERA-40 precipitation was rescaled so that the total snow water equivalent (SWE) on the SnowSTAR2002 observation dates equaled the observed values. The mean absolute error (MAE) of measured and simulated snow properties shows that SNTHERM was able to produce good simulations for snowpack temperature but larger errors for grain size and density. A spatial similarity analysis using semivariograms of measured profiles shows that there is diverse lateral and vertical variability for snow properties along the SnowSTAR2002 transect resulting from differences in initial snow deposition, influenced by wind, vegetation, topography, and postdepositional mechanical and thermal metamorphism. The correlation length in snow density (42 km) is quite low, whereas it is slightly longer for snow grain size (125 km) and longer still for snow temperature (130 km). An important practical question that the observed and reconstructed profiles allow to be addressed is the implications of model errors in the observed snow properties for simulated microwave emissions signatures. The Microwave Emission Model for Layered Snowpacks (MEMLS) was used to simulate 19- and 37-GHz brightness temperatures. Comparison of SNTHERM–MEMLS and SnowSTAR2002–MEMLS brightness temperatures showed a very good match occurs at 19 GHz [a root-mean-square error (RMSE) of 1.5 K (8.7 K) for vertical (horizontal) polarization] and somewhat larger [5.9 K (6.2 K) for vertical (horizontal) polarization] at 37 GHz. These results imply that the simulation of snow microphysical profiles is a viable strategy for passive microwave satellite–based retrievals of SWE.

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DePinto, J. V., R. Raghunathan, V. J. Bierman, P. W. Rodgers, T. C. Young, and S. C. Martin. "Analysis of Organic Carbon Sediment-Water Exchange in Green Bay, Lake Michigan, USA." Water Science and Technology 28, no. 8-9 (October 1, 1993): 149–59. http://dx.doi.org/10.2166/wst.1993.0613.

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A steady-state sediment carbon mass balance has been performed using data from the Green Bay Mass Balance Study. This analysis aided the calibration of sediment organic carbon resuspension for use in the time-variable PCB mass balance model of the bay. The steady-state analysis indicated that the spatial range of open water resuspension rates was 32 to 195 rara/y, with larger values in shallow, high energy areas of the bay. Under ice, resuspension rates ranged spatially from 15 to 63 mm/y. Gross water column to sediment deposition fluxes and gross resuspension fluxes were by far the largest paniculate carbon fluxes in the systems, with their difference leading to net deposition velocities that ranged spatially from 0.02 to 0.27 m/d during the open water period and from 0.09 to 0.64 m/d under ice.

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Xu, Jinchao, Wei Li, and Siyuan Meng. "Kinematic and Dynamic Simulation Analysis of Modified Conventional Beam Pumping Unit." Energies 15, no. 15 (July 29, 2022): 5496. http://dx.doi.org/10.3390/en15155496.

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The large net torque fluctuations in the reducer output shafts of conventional beam pumping units and the existence of negative torque are the decisive factors that lead to their low efficiency and high energy consumption. This study developed a positive torque modulation scheme for conventional beam pumping units, which was based on the principle of the follow-up secondary balance of the connecting rod. The CYJ10-4.2-53HF conventional beam pumping unit was selected as the research object. The kinematic and dynamic simulation analysis of the modified pumping unit was carried out using ADAMS software. The results showed that secondary balance torque curves could realize the function of “peak cutting and valley filling” for the curves after the primary balance and that the modified pumping unit could achieve a full-cycle positive value for the reducer output shaft and verify the feasibility of our modulation scheme. A secondary balance offset angle of 315° was the best choice as the amplitude of the torque curve clearly increased and the phase remained basically the same when the radius of the mass center of the secondary balance increased. Therefore, when the offset angle value of the secondary balance weight was determined, the radius of the mass center could be changed by adjusting the position of the secondary balance weight to achieve the balance adjustment.

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Bin, Peng, Vincent Lemort, Arnaud Legros, Zhang Hongsheng, and Gong Haifeng. "Variable thickness scroll compressor performance analysis—Part I: Geometric and thermodynamic modeling." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 231, no. 4 (April 11, 2016): 633–40. http://dx.doi.org/10.1177/0954408916640418.

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In order to investigate the performance of variable thickness scroll compressors, a detail mathematical modeling based on energy and mass balances is established in this two-part. In part I, the geometric modeling and thermodynamic modeling are developed. The profile based on circle involute, high order curve, and arc is built up using the base line method. The volume of working chambers from suction to discharge is defined. Thereafter, the evolution and derivative of the working chamber volume with respect to the orbiting angle are discussed. The energy and the mass balance for working chamber are described. Suction gas heating, radial and flank leakage, heat transfer between the working fluid, scroll wraps and plates are considered in the thermodynamic modeling. The established geometric modeling and thermodynamic modeling can provide better understanding of the variable thickness scroll compressor working process. The dynamical modeling and model validation are reported in part II.

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HEUETT, WILLIAM J., and HONG QIAN. "COMBINING FLUX AND ENERGY BALANCE ANALYSIS TO MODEL LARGE-SCALE BIOCHEMICAL NETWORKS." Journal of Bioinformatics and Computational Biology 04, no. 06 (December 2006): 1227–43. http://dx.doi.org/10.1142/s0219720006002430.

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Stoichiometric Network Theory is a constraints-based, optimization approach for quantitative analysis of the phenotypes of large-scale biochemical networks that avoids the use of detailed kinetics. This approach uses the reaction stoichiometric matrix in conjunction with constraints provided by flux balance and energy balance to guarantee mass conserved and thermodynamically allowable predictions. However, the flux and energy balance constraints have not been effectively applied simultaneously on the genome scale because optimization under the combined constraints is non-linear. In this paper, a sequential quadratic programming algorithm that solves the non-linear optimization problem is introduced. A simple example and the system of fermentation in Saccharomyces cerevisiae are used to illustrate the new method. The algorithm allows the use of non-linear objective functions. As a result, we suggest a novel optimization with respect to the heat dissipation rate of a system. We also emphasize the importance of incorporating interactions between a model network and its surroundings.

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Syahrul, S., S. Sukmawaty, A. Priyati, J. Sari, and M. Mirmanto. "Analysis of Heat Energy on the Drying Process of Paddy Using Fluidized Beds Dryer." IOP Conference Series: Earth and Environmental Science 913, no. 1 (November 1, 2021): 012038. http://dx.doi.org/10.1088/1755-1315/913/1/012038.

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Abstract The purpose of this study was to determine the amount of heat energy in the paddy drying process using a fluidized bed dryer. The method used in this research was an experimental method using an energy balance. This test was carried out using a fluidized beds dryer, with paddy material, where the paddy was dried at a certain temperature with 3 mass treatments, namely 5, 6 kg, and 7 kg with an air velocity of 21 m/s. The results showed that the total energy that enters the drying chamber for a mass of 5 kg material is 1,022 kJ with a useful energy of 1.339 kJ. The energy that enters the drying chamber for a mass of 6 kg is 1,043 kJ with a useful energy of 2.192 kJ. For a mass of 7 kg of material, the energy that enters the drying chamber is 1,187 kJ with a useful energy of 3.578 kJ.

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Zhang, Zhi, Bo Lin Li, Chi Zhang, and Hua Chai. "Analysis on Mass Balance and Optimization of Operating Performance in Anaerobic-Anoxic-Aerobic Oxidation Ditch Process." Advanced Materials Research 243-249 (May 2011): 4864–67. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.4864.

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The equations of COD, nitrogen and phosphate mass balance is established and the results show that the COD, nitrogen and phosphorus balance ratios are 98.3%, 73.1%, 98.4%. COD removal is achieved by the discharge of aerobic oxidation and excess sludge, accounting for 86.3% of the total. The loss of nitrogen balance is due to the existing of SND. Nitrogen removal is mainly achieved by the discharge of denitrification process, including anoxic denitrification process (33.6%) and SND process (23.3%). In order to solve the problem of large energy consumption, some optimized control measures are proposed and the test results indicate that TN removal rate has increased from 89.2% to 93.1%, tons of water at power consumption has dropped from 0.35 to 0.26kW•h/m3.

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Van Gerpen, J. H., and H. N. Shapiro. "Second-Law Analysis of Diesel Engine Combustion." Journal of Engineering for Gas Turbines and Power 112, no. 1 (January 1, 1990): 129–37. http://dx.doi.org/10.1115/1.2906467.

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A second-law analysis of the combustion process in a diesel engine is presented for a single-zone model. Expressions for availability and the availability balance are developed in detail from the energy and entropy balances and applied in a manner that allows the irreversibility due to combustion to be separated from that associated with heat transfer to the walls. Availability is divided into two components: thermomechanical and chemical availability. For the first time, chemical availability of the cylinder contents is dealt with rigorously, which allows for a correct determination of combustion irreversibilities. The analysis is applied in a parametric study of the effects of combustion timing, mass burning rate, and heat transfer rate on the irreversibility and system availability.

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Kagawa, Takahiro. "Validation of Balance Map Analysis of Walking at Different Speeds." Applied Bionics and Biomechanics 2022 (March 23, 2022): 1–9. http://dx.doi.org/10.1155/2022/9268134.

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Walking balance about falling in the forward direction is associated with the body’s center of mass and placement of the swing foot during the swing phase. Balance map analysis evaluates walking balance based on the prediction of the reachability of an appropriate foot placement using a simple biomechanical model during the swing phase without active joint torque (ballistic walking model). The ballistic walking model can be justified in terms of the preferred walking speed because the metabolic energy consumption associated with muscle activity in faster and slower walking is higher than that in preferred speed walking. Therefore, the assumption that the active joint torque is sufficiently small during the swing phase may not hold in faster or slower walking, which can be a significant limitation of balance map analysis. In this study, it was hypothesized that steady-state walking at various walking speeds would be evaluated as stable for validation of the balance map analysis, and the gait patterns for three types of walking speeds (slow, normal, and fast) were examined. The results showed that the trajectories during the swing phase were within stable regions for all conditions, with a sufficient margin from the forward balance loss region. In addition, the margin from forward balance was reduced with an increase in walking velocity. The decrease in the margin during fast walking resulted from an increase in the forward velocity of the body’s center of mass in relation to the velocity of the swing leg. These results suggest that balance map analysis effectively measures walking balance at various speeds.

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Saravanakumar, Ayyadurai, Wei-Hsin Chen, Kantha Deivi Arunachalam, Young-Kwon Park, and Hwai Chyuan Ong. "Pilot-scale study on downdraft gasification of municipal solid waste with mass and energy balance analysis." Fuel 315 (May 2022): 123287. http://dx.doi.org/10.1016/j.fuel.2022.123287.

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Rao, M. S., S. P. Singh, M. S. Sodha, A. K. Dubey, and M. Shyam. "Stoichiometric, mass, energy and exergy balance analysis of countercurrent fixed-bed gasification of post-consumer residues." Biomass and Bioenergy 27, no. 2 (August 2004): 155–71. http://dx.doi.org/10.1016/j.biombioe.2003.11.003.

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Goran, M. I., J. Calles-Escandon, E. T. Poehlman, M. O'Connell, and E. Danforth. "Effects of increased energy intake and/or physical activity on energy expenditure in young healthy men." Journal of Applied Physiology 77, no. 1 (July 1, 1994): 366–72. http://dx.doi.org/10.1152/jappl.1994.77.1.366.

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This study was designed to examine effects of alterations in energy balance on adaptive changes in components of total energy expenditure (TEE). Nineteen young healthy males were studied during a 10-day sedentary energy balance baseline period and then randomly assigned to one of four 10-day treatment groups: 1) no change in energy intake (EI) or physical activity (PA; energy balance at low energy flux), 2) EI increased by 50% with no change in PA (positive energy balance), 3) TEE increased by 50% by increasing PA, matched by a 50% increase in EI (energy balance at high energy flux), and 4) TEE increased by 50% by increasing PA with no change in EI (negative energy balance). TEE was measured with doubly labeled water, resting metabolic rate (RMR) by indirect calorimetry, and thermic response to feeding (TEF) by indirect calorimetry; energy expenditure of physical activity (EEPA) was estimated by subtracting RMR, TEF, and prescribed PA from TEE. TEE was significantly increased by PA (by design) but not EI. There was a significant main effect of intake and a significant intake-by-activity interaction for changes in RMR. In post hoc analysis, RMR was significantly increased during positive energy balance and energy balance at high energy flux relative to change in RMR when energy balance was maintained at low energy flux. A significant increase in RMR was also noted during negative energy balance after adjustment for change in fat-free mass. There was no significant difference in change in RMR among the three treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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Temporim, Ramoon B. L., Alessandro Petrozzi, Valentina Coccia, Franco Cotana, and Gianluca Cavalaglio. "A Prototype Plant for Oilseed Extraction: Analysis of Mass and Energy Flows." Sustainability 12, no. 22 (November 23, 2020): 9786. http://dx.doi.org/10.3390/su12229786.

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The focus of this study is to analyze the energy flows related to cardoon oil processing based on the estimated electricity consumption. It was carried out in a prototype oilseed extraction plant located in Umbria Region, Italy. This installation consists of the following processes: seed weight-storage, transportation, sifting, milling, filtering, and oil storage. Approximately 49,000 kg dry basis (DB) of cardoon seeds (Cynara cardunculus) were processed. Cardoon seeds were chosen as a feedstock due to their sustainability characteristics. Before processing, samples of raw material were analyzed in terms of moisture, oil content, impurity, density, and lower heating value. The input–output flows were measured in terms of weight and energy consumption. Its data were used to perform the mass-energy balance and estimate the efficiency of processes. About 8505 kg of filtered oil was obtained from raw material. The efficiency of the process chain was 84.42% concerning the oil content in the seeds. For the same period, the plant required a total of 17,556 MJ of electric energy from the grid for its operation. 321,507 MJ were obtained from oil and 688,875 MJ from oilcake. About 5.48% of the energy produced by oil extraction was virtually used in the process.

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Shin, Kook-Sik, Seung-Hwan Kim, Seong-Yong Oh, Sang-En Lee, Chang-Hyun Kim, and Young-Man Yoon. "Study for Clean Energy Farming System by Mass and Energy Balance Analysis in the Controlled Cultivation of Vegetable Crop (Cucumber)." Korean Journal of Soil Science and Fertilizer 45, no. 2 (April 30, 2012): 280–86. http://dx.doi.org/10.7745/kjssf.2012.45.2.280.

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Saputro, Erwan Adi, Rachmad Ramadhan Yogaswara, Nerissa Arviana, Luckyana Aini, A. R. Yelvia Sunarti, and Reva Edra Nugraha. "Mass Balance Analysis of Bioethanol Production from Petai Peel (Parkia speciosa) through Enzymatic Process." International Journal of Eco-Innovation in Science and Engineering 2, no. 02 (November 29, 2021): 29–32. http://dx.doi.org/10.33005/ijeise.v2i02.48.

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The consumption of fuel for transportation is increasing during the last decade. Bioethanol is one of the renewable energy has a good opportunity to be applied when the lack of fossil fuel. Bioethanol is derived from the lignocellulose substance through a fermentation process. In this research, the lignocellulose came from the petai peel (Parkia speciosa). The peel was hydrolyzed using an enzyme and continuously fermented for 5 days. The aim of this research is to analyst the mass balance of the bioethanol production from petai peel (Parkia speciosa) through the enzymatic process. The enzyme used in this research are alfa amylase (10 ml) and glucoamylase (10 ml), also Saccharomyces cerevisiae used in the fermentation process. The result shows that the initial material of petai peel was 57 grams will produce bioethanol around 14 grams.

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Syguła, Ewa, Kacper Świechowski, Małgorzata Hejna, Ines Kunaszyk, and Andrzej Białowiec. "Municipal Solid Waste Thermal Analysis—Pyrolysis Kinetics and Decomposition Reactions." Energies 14, no. 15 (July 26, 2021): 4510. http://dx.doi.org/10.3390/en14154510.

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In this study, 12 organic waste materials were subjected to TG/DTG thermogravimetric analysis and DSC calorimetric analysis. These analyses provided basic information about thermochemical transformations and degradation rates during organic waste pyrolysis. Organic waste materials were divided into six basic groups as follows: paper, cardboard, textiles, plastics, hygiene waste, and biodegradable waste. For each group, two waste materials were selected to be studied. Research materials were (i) paper (receipts, cotton wool); (ii) cardboard (cardboard, egg carton); (iii) textiles (cotton, leather); (iv) plastics (polyethylene (PET), polyurethane (PU)); (v) hygiene waste (diapers, leno); and (vi) biodegradable waste (chicken meat, potato peel). Waste materials were chosen to represent the most abundant waste that can be found in the municipal solid waste stream. Based on TG results, kinetic parameters according to the Coats–Redfern method were determined. The pyrolysis activation energy was the highest for cotton, 134.5 kJ × (mol∙K)−1, and the lowest for leather, 25.2 kJ × (mol∙K)−1. The DSC analysis showed that a number of transformations occurred during pyrolysis for each material. For each transformation, the normalized energy required for transformation, or released during transformation, was determined, and then summarized to present the energy balance. The study found that the energy balance was negative for only three waste materials—PET (−220.1 J × g−1), leather (−66.8 J × g−1), and chicken meat (−130.3 J × g−1)—whereas the highest positive balance value was found for potato peelings (367.8 J × g−1). The obtained results may be applied for the modelling of energy and mass balance of municipal solid waste pyrolysis.

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Maussion, F., W. Gurgiser, M. Großhauser, G. Kaser, and B. Marzeion. "ENSO influence on surface energy and mass balance at Shallap Glacier, Cordillera Blanca, Peru." Cryosphere 9, no. 4 (August 21, 2015): 1663–83. http://dx.doi.org/10.5194/tc-9-1663-2015.

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Abstract. The El Niño/Southern Oscillation (ENSO) is a major driver of climate variability in the tropical Andes, where recent Niño and Niña events left an observable footprint on glacier mass balance. The nature and strength of the relationship between ENSO and glacier mass balance, however, varies between regions and time periods, leaving several unanswered questions about its exact mechanisms. The starting point of this study is a 4-year long time series of distributed surface energy and mass balance (SEB/SMB) calculated using a process-based model driven by observations at Shallap Glacier (Cordillera Blanca, Peru). These data are used to calibrate a regression-based downscaling model that links the local SEB/SMB fluxes to atmospheric reanalysis variables on a monthly basis, allowing an unprecedented quantification of the ENSO influence on the SEB/SMB at climatological time scales (1980–2013, ERA-Interim period). We find a stronger and steadier anti-correlation between Pacific sea-surface temperature (SST) and glacier mass balance than previously reported. This relationship is most pronounced during the wet season (December–May) and at low altitudes where Niño (Niña) events are accompanied with a snowfall deficit (excess) and a higher (lower) radiation energy input. We detect a weaker but significant ENSO anti-correlation with total precipitation (Niño dry signal) and positive correlation with the sensible heat flux, but find no ENSO influence on sublimation. Sensitivity analyses comparing several downscaling methods and reanalysis data sets resulted in stable mass balance correlations with Pacific SST but also revealed large uncertainties in computing the mass balance trend of the last decades. The newly introduced open-source downscaling tool can be applied easily to other glaciers in the tropics, opening new research possibilities on even longer time scales.

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Maussion, F., W. Gurgiser, M. Großhauser, G. Kaser, and B. Marzeion. "ENSO influence on surface energy and mass balance at Shallap Glacier, Cordillera Blanca, Peru." Cryosphere Discussions 9, no. 3 (May 28, 2015): 2999–3053. http://dx.doi.org/10.5194/tcd-9-2999-2015.

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Abstract. The El Niño/Southern Oscillation (ENSO) is a major driver of climate variability in the tropical Andes, where recent Niño and Niña events left an observable footprint on glacier mass balance. The nature and strength of the relationship between ENSO and glacier mass balance, however, varies between regions and time periods, leaving several unanswered questions about its exact mechanisms. The starting point of this study is a four-year long time series of distributed surface energy and mass balance (SEB/SMB) calculated using a process-based model driven by observations at Shallap Glacier (Cordillera Blanca, Peru). These data are used to calibrate a regression-based downscaling model that links the local SEB/SMB fluxes to atmospheric reanalysis variables on a monthly basis, allowing an unprecedented quantification of the ENSO influence on the SEB/SMB at climatological time scales (1980–2013, ERA-Interim period). We find a stronger and steadier anti-correlation between pacific sea surface temperature (SST) and glacier mass balance than previously reported. This relationship is most pronounced during the wet season (December–May) and at low altitudes where Niño (Niña) events are accompanied with a snowfall deficit (excess) and a higher (lower) radiation energy input. We detect a weaker but significant ENSO anti-correlation with total precipitation (Niño dry signal) and positive correlation with the sensible heat flux, but find no ENSO influence on sublimation. Sensitivity analyses comparing several downscaling methods and reanalysis datasets resulted in stable mass balance correlations with pacific SST but also revealed large uncertainties in computing the mass balance trend of the last decades. The newly introduced open-source downscaling tool can be applied easily to other glaciers in the tropics, opening new research possibilities on even longer time scales.

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Bendea, Gabriel, Ioan Felea, Cristina Hora, Codruta Bendea, Adrian Felea, and Alin Blaga. "Energy Performance Analysis of a Heat Supply System of a University Campus." Energies 16, no. 1 (December 23, 2022): 174. http://dx.doi.org/10.3390/en16010174.

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The energy efficiency of a system and the performance level of its equipment and installations are the two key elements based on which the investment decision in its modernization is made. They are also very important for setting up optimal operation strategies. The energy audit is a well-known and worldwide recognized tool for calculating energy performance indicators and developing improvement measures. This paper is a synthesis of the energy audit results performed for a district heating network that uses geothermal energy as its primary source of energy. The location of the heating system is inside a university campus. The first part explains the necessity of a comprehensive study on district heating networks and introduces the defining elements that characterize the analyzed equipment and installations. The complex energy balance methodology that has been developed and applied to this district heating system is presented in the second part of the paper. Next, the methodology for collecting the input data for the energy and mass balance is explained. In the final part, the numerical values of the performance indicators and the technical measures that must be applied to improve energy efficiency are shown, and conclusions are drawn.

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Zolles, Tobias, and Andreas Born. "Sensitivity of the Greenland surface mass and energy balance to uncertainties in key model parameters." Cryosphere 15, no. 6 (June 28, 2021): 2917–38. http://dx.doi.org/10.5194/tc-15-2917-2021.

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Abstract. We investigate the sensitivity of a distributed glacier surface mass and energy balance model using a variance-based analysis, for two distinct periods of the last glacial cycle: the present day (PD) and the Last Glacial Maximum (LGM). The results can be summarized in three major findings: the sensitivity towards individual model parameters and parameterizations is as variable in space as it is in time. The model is most sensitive to uncertainty related to atmospheric emissivity and the down-welling longwave radiation. While the turbulent latent heat flux has a sizable contribution to the surface mass balance uncertainty in central Greenland today, it dominates over the entire ice sheet during the cold climate of the LGM, in spite of its low impact on the overall surface mass balance of the Greenland ice sheet in the modern climate. We conclude that quantifying the model sensitivity is very helpful for tuning free model parameters because it clarifies the relative importance of individual parameters and highlights interactions between them that need to be considered.

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Journal articles on the topic 'Mass and energy balance analysis'

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