Energy Balance Studies Research Articles

Assessment of Local Climate Zone Classification Maps of Cities in China and Feasible Refinements

Local climate zone (LCZ) maps that describe the urban surface structure and cover with consistency and comparability across cities are gaining applications in studies of urban heat waves, sustainable urbanization and urban energy balance. Following the standard World Urban Database and Access Portal Tools (WUDAPT) method, we generated LCZ maps for over 20 individual cities and 3 major economic regions in China. Based on the confusion matrices constructed by manual comparison between the predicted classes and ground truths, we highlight the following: (1) notable variation in overall accuracies (i.e., 60%–89%) among cities were observed, which was mainly due to class incompleteness and distinct proportions of natural landscapes; (2) building classes in selected cities were poorly classified in general, with a mean accuracy of 48%; (3) the sparsely built class (i.e., LCZ 9), which is rare in the selected Chinese cities, had the lowest classification accuracy (32% on average), and the class of low plants had the widest accuracy range. The findings indicate that the standard WUDAPT method alone is insufficient for generating LCZ products that demonstrate practical value, especially for built-up areas in China, and the misclassification is largely caused by the lack of building height data. This result is confirmed by a refinement test, in which the urban DEM retrieved from Sentinel-1 data with radar interferometry technique was used. The study shows a detailed and comprehensive assessment of applying the WUDAPT method in China and a feasible refinement strategy to improve the classification accuracy, especially for the built-up types of LCZ. The study could serve as a useful reference for generating quality-ensured LCZ maps. This study also examines and explores the relationship between socio-economic status and LCZ products, which is essential for further implementations.

Flow through calorimeter to measure fluid heat capacity in CSP applications

Performance tests of concentrating solar collectors are based on energy balance studies which require accurate measurements of fluid mass flow rate, temperature difference over the collector length and the knowledge of the specific heat capacity of the used heat transfer fluid (HTF). Especially at operation temperatures in the range of 200–400 °C, the accuracy of HTF manufacturer data regarding the specific heat capacity of used HTFs is insufficient. This shortcoming contributes significantly to the overall measurement uncertainty of thermal collector assessments. In the present paper, the measurement results of a flow through calorimeter measuring the specific heat capacity of SYLTHERM 800 under field conditions at temperatures up to 330 °C are presented. The HTF measurement shows good agreement (deviation below 1.2%) with a Differential Scanning Calorimetry (DSC) measurement for temperatures below 270 °C. For higher temperatures, the deviation between flow through calorimeter and DSC measurement increases to 3.7% at 330 °C. Furthermore, several technical design and measurement improvements over the calorimeter design presented in 2012 are described in detail. A validation measurement using water reveals deviations below 0.1% from the water reference values at ambient temperatures. A stringent uncertainty analysis reveals the largest individual measurement uncertainty. The unexpectedly large uncertainty of the Coriolis mass flow sensors at temperatures above 270 °C is distinguished by a large individual uncertainty and the comparison to DSC.

Adequacy of Critical Nutrients Affecting the Quality of the Spanish Diet in the ANIBES Study.

Diet is one of the key modifiable behaviors that can help to control and prevent non-communicable chronic diseases. Therefore, it is important to evaluate the overall diet composition of the population through non-invasive and independent indexes or scores as diet quality indexes (DQIs). The primary aim of the present work was to estimate the adequacy of the intake of critical nutrients in the Spanish “Anthropometry, Intake, and Energy Balance Study” (ANIBES) (n = 2285; 9–75 years), considering, as a reference, the European Food Scientific Authority (EFSA) values for nutrients for the European Union. We also assessed the quality of the diet for adults and older adults using four internationally accepted DQIs, namely the Healthy Diet Indicator (HDI), the Mediterranean Diet Score (MDS), the Mediterranean Diet Score-modified (MDS-mod), and the Mediterranean-Diet Quality Index (MED-DQI), as well as the ANIBES-DQI, stratified by education and income. The ANIBES-DQI was based on compliance with EFSA and Food and Agriculture Organization recommendations for a selected group of nutrients (i.e., total fat, saturated fatty acids (SFAs), simple sugars, fiber, calcium, vitamin C, and vitamin A), with a total range of 0–7. Misreporting was assessed according to the EFSA protocol, which allowed us to assess the DQIs for both the general population and plausible reporters. The majority of the Spanish population had high intakes of SFAs and sugars and low intakes of fiber, folate, and vitamins A and C. In addition, about half of the population had low DQI scores and exhibited low adherence to the Mediterranean diet pattern. Overall, older adults (>65–75 years) showed better DQIs than adults (18–64 years), without major differences between men and women. Moreover, primary education and low income were associated with low MDS and ANIBES-DQI scores. For the ANIBES-DQI, the percentage of the population with low scores was higher in the whole population (69.5%) compared with the plausible energy reporters (49.0%), whereas for medium and high scores the percentages were higher in plausible reporters (41.2% vs. 26.2% and 9.8% vs. 4.3%, respectively). In conclusion, the present study adds support to marked changes in the Mediterranean pattern in Spain, and low education and income levels seem to be associated with a low-quality diet. Additionally, the misreported evaluation in the ANIBES population suggests that this analysis should be routinely included in nutrition surveys to give more precise and accurate data related to nutrient intake and diet quality.

Anaerobic co-digestion of food waste with pretreated yard waste: A comparative study of methane production, kinetic modeling and energy balance

Abstract Solid state anaerobic digestion of food waste (FW) with yard waste (YW) appears to be an efficient technique for bioenergy production. However, the reluctant nature of YW and nutrient imbalance due to high C/N ratio are the two major obstacles for maximum methane production. In this study to improve the methane production potential, YW was thermally pretreated to reduce its recalcitrance nature and then the pretreated YW was co-digested with FW to balance nutrient for anaerobic co-digestion. Moreover, optimization of F/M (Food/Microorganism) ratios (1.0, 1.5, 2.0 and 2.5) for solid state anaerobic co-digestion was also considered. The highest methane production of 431 mL/gVSadded was observed for co-digestion of FW with microwave pretreated YW at the F/M ratio of 1.5. Energy balance of the pretreatment technique was conducted and the highest net energy gain 3.98 kJ/gVS (= output energy of 14.04 kJ/gVS - input energy of 10.05 kJ/g VS) obtained at the F/M ratio of 1.0.

A Mobile System to Improve Quality of Life Via Energy Balance in Breast Cancer Survivors (BENECA mHealth): Prospective Test-Retest Quasiexperimental Feasibility Study

BackgroundEnergy balance is defined as the difference between energy expenditure and energy intake. The current state of knowledge supports the need to better integrate mechanistic approaches through effective studies of energy balance in the cancer population because of an observed significant lack of adherence to healthy lifestyle recommendations. To stimulate changes in breast cancer survivors’ lifestyles based on energy balance, our group developed the BENECA (Energy Balance on Cancer) mHealth app. BENECA has been previously validated as a reliable energy balance monitoring system.ObjectiveBased on our previous results, the goal of this study was to investigate the feasibility of BENECA mHealth in an ecological clinical setting with breast cancer survivors, by studying (1) its feasibility and (2) pretest-posttest differences with regard to breast cancer survivor lifestyles, quality of life (QoL), and physical activity (PA) motivation.MethodsEighty breast cancer survivors diagnosed with stage I to IIIA and with a body mass index over 25 kg/m2 were enrolled in this prospective test-retest quasi-experimental study. Patients used BENECA mHealth for 8 weeks and were assessed at baseline and the postintervention period. Feasibility main outcomes included percentage of adoption, usage, and attrition; user app quality perception measured with the Mobile App Rating Scale (MARS); satisfaction with the Net Promoter Score (NPS); and barriers and facilitators of its use. Clinical main outcomes included measuring QoL with the European Organization for Research and Treatment of Cancer QoL Questionnaire Core 30 (EORT QLQ-C30), PA assessment with accelerometry, PA motivation measure with a Spanish self-efficacy scale for physical activity (EAF), and body composition with dual-energy x-ray absorptiometry. Statistical tests (using paired-sample t tests) and Kaplan-Meier survival curves were analyzed.ResultsBENECA was considered feasible by the breast cancer survivors in terms of use (76%, 58/76), adoption (69%, 80/116), and satisfaction (positive NPS). The app quality score did not make it one of the best-rated apps (mean 3.71, SD 0.47 points out of 5). BENECA mHealth improved the QoL of participants (global health mean difference [MD] 12.83, 95% CI 8.95-16.71, P<.001), and EAF score (global MD 36.99, 95% CI 25.52-48.46, P<.001), daily moderate-to-vigorous PA (MD 7.38, 95% CI 0.39-14.37, P=.04), and reduced body weight (MD −1.42, 95% CI −1.97 to −0.87, P<.001).ConclusionsBENECA mHealth can be considered feasible in a real clinical context to promote behavioral changes in the lifestyles of breast cancer survivors, but it needs to be enhanced to improve user satisfaction with use and functionality. This study highlights the importance of the use of mobile apps based on energy balance and how the QoL of breast cancer survivors can be improved via monitoring.

Human Osteoblast Cell Behaviour on Titanium Discs Treated with Argon Plasma.

(1) Background. Titanium is characterized by its biocompatibility and resistance to stress and fatigue. Treatment with argon plasma may favour growth of human osteoblasts with respect to cell adhesion and proliferation. The aim of this study was to analyse the behaviour of human osteoblasts (MG-63) on Grade IV and V titanium possessing a sand-blasted, acid-etched (SLA) surface. SLA is a widely used surface treatment to create micro- and macroretentions to enhance osteoconductive properties on the surface. (2) Methods. One group of each grade of titanium was decontaminated with argon plasma and compared. On each disc, 20 × 104 cells were cultivated for morphological analysis, study of cell viability (regarding a negative control [100% viability]) and mitochondrial energy balance. (3) Results. At 24 h titanium treated with SLA showed a higher percentage of cell viability (47.3 ± 8.1%) compared to titanium IV treated with argon plasma, which presented a percentage of 79.1 ± 1.1%. Grade V titanium treated with argon plasma presented a higher viability percentage 91.3 ± 3.0% whereas nontreated Grade V titanium presented 53.3 ± 4.0%. Cells cultivated on the surfaces with an argon-plasma treatment were enlarged in comparison to non-treated discs. The cells with smaller circularity with a greater spread and spindle shape were the ones cultivated on the Grade V titanium surface. Cells seeded on treated titanium IV and titanium V, treated or not, showed higher mitochondrial activity over nontreated titanium IV. (4) Conclusions. Cells cultivated on those Grade V titanium discs that were decontaminated with argon plasma presented higher levels of cell adhesion and proliferation, lower mitochondrial damage and a higher mean cell area compared to those not decontaminated with argon plasma.

Soil moisture estimation with a remotely sensed dry edge determination based on the land surface temperature-vegetation index method

As a crucial parameter in land surface systems, soil moisture plays an important role in surface energy balance studies, environmental detection, and global climate change research. Remotely sensed data have been used for estimating soil moisture through different approaches, which has resulted in many achievements. Previous studies showed that the land surface temperature (LST) vegetation index method (LST-VI method) can obtain surface soil moisture with remote sensing sources, and it is relatively simple and easy to operate at a regional scale. However, one thorny difficulty is the dry edge determination from the LST-VI feature space. In this study, a remote sensing method is proposed to determine the theoretical dry edge from the LST-VI scatter plots, which do not require any ground measured auxiliary data. Based on the surface energy balance principle, this method derived the maximum LSTs for bare soil and full vegetation cover using MODIS products. The air temperature is parameterized by the LST using a semiempirical formula as the theoretical wet edge. The estimated soil moisture is validated by in situ measurements at a comprehensive weather station of Yucheng. The coefficient of determination is ∼0.60, and the root mean square error is about 0.08 m3 / m3. The relevant key parameters in determining the dry edge are also validated from the meteorological observation. The air temperature and net surface shortwave radiation flux all reach a very high level, with an RMSE of 3.75 k and 49.3 W m − 2, respectively. The results demonstrated that the proposed method can derive the accurate dry edge to estimate soil moisture from the remote sensing data, which will provide great help for future studies of soil moisture estimation using remote sensing techniques.

Creation of a Novel Inbred Mouse Model for High Activity with a Small Muscle Phenotype

Given challenges of studying skeletal form and function in humans, experimental models of skeletal loading are important for understanding both basic and applied questions of the musculoskeletal and associated physiological systems (e.g., energy balance, metabolism, behavior). Experimental approaches have frequently involved controlled loading, often axial loads placed on the ulna or tibia. Although appealing in allowing for precise estimates of stress and strain, these approaches often generate extremely high tissue strains, resulting in potentially pathological overload. Conversely, natural models of locomotor loading result in unknown levels of tissue strain but benefit by representing behaviors that animals will perform in life. Voluntary locomotion via an activity wheel can be used to explore the behavioral and physiological challenges of long‐term voluntary exercise. Furthermore, because activity is a heritable trait, it can be selected upon to gradually increase across generations. From an outbred experimental population of Hsd:ICR mice that had already experienced 51 generations of selective breeding for high levels of voluntary wheel‐running behavior (resulting in an approximately 2.5–3‐fold increase in activity over non‐selected controls), we began inbreeding via sib‐sib mating while simultaneously continuing selection for activity. These mice were also homozygous for an allele that results in an approximately 50% reduction in limb muscle mass. At generation 30 of inbreeding, the Hsd:ICR‐Myh4minimsc mice were found to engage in an average of 487 minutes (females) and 371 minutes (males) of activity, with a mean speed of 13.1 m/min (females) and 14.7 m/min (males). These activity values place Hsd:ICR‐Myh4minimsc at the high end of duration and the mid‐range of speed, when compared with other inbred strains. When housed without wheels and compared with outbred ICR mice, Hsd:ICR‐Myh4minimsc mice have significantly lower body mass (27.9 ± 3.7 g sd vs 40.1 ± 5.9 g) and abdominal adipose tissue (0.18 ± 0.06 g vs. 0.30 ± 0.06 g) at 17 weeks of age. Compared with other inbred, high‐activity strains, Hsd:ICR‐Myh4minimsc has advantages with good overall health, strong breeding success, and large litters (median 10 pups/litter). After 39 generations of brother‐sister mating, we estimate &gt; 99.9% homozygosity, at which point the line was transferred to the Mutant Mouse Resource and Research Center, where it will be available to the community as a model system for studies of high voluntary exercise, energy balance, skeletal phenotypes, and musculoskeletal integration.Support or Funding InformationNSF DEB‐1655362 (to TG); NIH NIAMS EARDA sub‐award from 5G11HD052368‐03 (to KMM); California University San Bernardino Department of Biology (to KMM); University of Missouri School of Medicine (to KMM)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Hysteresis resulting in forestry heat storage underestimation: A case study of plantation forestry in northern China

Heat storage (Q) is an important component of the near-surface energy balance, and has been increasingly considered in recent energy balance studies. Studies have revealed that the hysteresis of heat storage was always been ignored, which leaded to the underestimation of heat storage proportion in energy balance.So, for further understanding the role of hysteresis effect in forestry heat storage, an observation experiment of heat storage in forestry of Pinus sylvestris var. mongolica Litv forestry - a common species in northern China - was conducted. Heat storage in the atmosphere beneath canopy, in the canopy biomass, and in the soil above a soil heat-flow plate were monitored continuously, to determine the distribution of stored heat, and solar radiation was simultaneously monitored to verify the hysteresis of heat storage versus radiation. Seasonal variations were separately analyzed to further clarify phenological effect on hysteresis. Correlation relationship was tested of lag time and underestimated energy versus climatic factors and physiological characteristics, for clarifying the reasons that resulting in hysteresis differences under different experimental day.The main results were as follows: (1) Hysteresis exists in heat storage and the lag time was 3.79 h in our study area; (2) The evaluation of hysteresis is crucial to avoid an underestimation of heat storage. Correction of lag time increases the heat storage proportion in R from 3.78% to 8.48%; (3) Increasing of air temperature and humility daily differences will enhance the underestimated energy. High radiation condition will weak the underestimation on heat storage and short the lag time. Soil moisture and leaf area index were not effect energy hysteresis significantly in sandy vegetation. Climatic factors were the main reason that resulting in the differences of hysteresis.This study helps to improve understanding energy transmitting in canopy and offering a new view in solving surface energy imbalance.

A Study of Energy Balance in Deformed Metals for Assessment of Damage Accumulation Stage

The work is devoted to study of energy balance in metals under plastic deformation and failure. Based on our previous experimental results we develop a phenomenological thermodynamic model of heat dissipation in metals. It allows us to simulate the energy balance under plastic deformation, to study the failure process of metals based on the stored energy criterion and the process of fatigue crack propagation. New internal thermodynamic variable is introduced as defect induced deformation and calculated based on the solution of statistical problem of mesodefect evolution. The developed model is adapted for using in standard final-elements numerical code (Abaqus) to simulate energy dissipation under quasi-static and cyclic loading in 3D geometries. The theoretical results were illustrated by computing of energy dissipation both under tensile test of Armco iron specimens and crack propagation under cyclic loading.

Study of CO2 Flow and Energy Balance in a Transition Forest in Southwestern Amazonia by the Modified Bowen Ratio Methods and Eddy Covariance

Study of CO2 Flow and Energy Balance in a Transition Forest in Southwestern Amazonia by the Modified Bowen Ratio Methods and Eddy Covariance

Energy Balance and Blood Metabolites Status of Local Sheep Based on Indigofera sp and Sproutbean Waste Ration

&lt;p&gt;This research was undertaken to evaluate energy utilization and blood metabolites status of male Indonesian local sheep involving nutrient balances and using urea space techniques for measurement body composition. Factorial randomized completely design was used in this study using 16 growing male local sheep. Factor A was breed which consisted of 8 Garut sheep (av.BW 14.90 kg) and 8 Jonggol sheep (av.BW 13.60 kg). Factor B was different ration which received of diet containing Indigoferasp. and sproutbean waste. The ration offered were pellets containing CP around 16% and energy 15.6 MJ GE/kg. Energy balance and blood metabolites studies were conducted during three-months trial. Intake, digestibility, urinary and metabolism variables were measured based on total collection method. Methane energy was measured by rusitec technique and methane gas production multiplied by calory equivalent value of methane. Energy retention (RE) was measured by urea space technique. Heat production was calculated from ME-RE. Plasma glucose, cholesterol and urea-N were measured by using spectrophotometry. Results showed that there were signiϐicant differences of energy intakes, digestibilities and metabolism among the rations. Animals fed with sproutbean waste ration has higher energy utilization compared to those fed Indigofera sp ration. There were no signiϐicant different for all blood metabolite variables among breed and its interaction between combination treatments. It is concluded that sproutbean waste in local sheep ration has higher energy utilization and daily gain than Indigofera sp.&lt;/p&gt;

Análisis del sector energético del Paraguay. Balance energético en energía útil 2011

El presente trabajo se enfoca en el análisis del sector energético paraguayo partiendo del primer Balance Energético en Energía Útil del Paraguay, elaborado mediante un proyecto conjunto entre la Itaipu Binacional y la Fundación Parque Tecnológico Itaipu - Paraguay, con la colaboración de la Fundación Bariloche - Argentina, tomando como año base el 2011. En el análisis se examina la situación del sector energético paraguayo en materia de energía hidroeléctrica, así como de los demás componentes de la Matriz Energética del Paraguay. El estudio compara los diferentes sectores de consumo de energía: Residencial, Industrial, Transporte, Agropecuario y Forestal, así como Comercial, Servicios y Público. El trabajo también presenta iniciativas en eficiencia energética que se han implementado en algunos sectores, destacando medidas que se esperan sean implementadas para incentivar el uso racional de la energía en todas sus fuentes. Finalmente, a modo de complemento, se exponen los principales resultados de la actualización al año 2013 del Balance Energético en Energía Útil empleado para la elaboración de la Prospectiva Energética Nacional, base para la formulación de la Política Energética Paraguay 2040

HERschelObservations of Edge-on Spirals (HEROES)

We present results of the detailed dust energy balance study for the seven large edge-on galaxies in the HEROES sample using three-dimensional (3D) radiative transfer (RT) modelling. Based on available optical and near-infrared (NIR) observations of the HEROES galaxies, we derive the 3D distribution of stars and dust in these galaxies. For the sake of uniformity, we apply the same technique to retrieve galaxy properties for the entire sample: we use a stellar model consisting of a Sérsic bulge and three double-exponential discs (a superthin disc for a young stellar population and thin and thick discs for old populations). For the dust component, we adopt a double-exponential disc with the new THEMIS dust-grain model. We fit oligochromatic RT models to the optical and NIR images with the fitting algorithmFITSKIRTand run panchromatic simulations with theSKIRTcode at wavelengths ranging from ultraviolet to submillimeter. We confirm the previously stated dust energy balance problem in galaxies: for the HEROES galaxies, the dust emission derived from our RT calculations underestimates the real observations by a factor 1.5–4 for all galaxies except NGC 973 and NGC 5907 (apparently, the latter galaxy has a more complex geometry than we used). The comparison between our RT simulations and the observations at mid-infrared–submillimetre wavelengths shows that most of our galaxies exhibit complex dust morphologies (possible spiral arms, star-forming regions, more extended dust structure in the radial and vertical directions). We suggest that, in agreement with results from the literature, the large- and small-scale structure is the most probable explanation for the dust energy balance problem.

Determination of soil ground heat flux through heat pulse and plate methods: Effects of subsurface latent heat on surface energy balance closure

The soil heat flux plate method is popularly applied in surface energy balance studies. Previous studies have shown that impervious plate blocks the flow of water and vapor within soil. Soil heat flux is generally commonly measured below surface, and its exact constitution is required in calculating surface energy balance. When subsurface evaporation occurs, subsurface latent heat sink constitutes an important proportion of the apparent ground heat flux. However, the plate method fails to detect such occurrence. In aboveground meteorological measurement, evaporated vapor moving out of soil profile is also being detected and the subsurface latent heat sink is recognized as part of turbulent latent heat flux. Thus, caution should be exercised when excluding the potential error from double counting of subsurface latent heat sink in surface energy balance evaluation. In this study, two common combination methods were used to determine the ground heat flux without latent heat sink (G0). One method is a combination of gradient-based heat pulse measurements and calorimetric method (GradC), and the other method is a combination of plate measurements at shallow depths and calorimetric method (PlateC). Results demonstrated that, in contrast to the PlateC method, the GradC method minimized the disturbance in soil structure and reduced the disruption in heat and water flow. Furthermore, the estimated G0 from the PlateC method was only 49.2% of that of the GradC method during daytime. Moreover, surface energy balance closure (EBC) was evaluated using the estimated G0 and aboveground turbulent energy flux data. In comparison with the PlateC method, the GradC method improved the surface EBC from 79.3% to 87.7% during daytime. In summary, accurate knowledge on the composition of ground heat flux and the location of water evaporation is necessary to calculate surface energy balance during micro-meteorology measurements.

Turbulence micro-meteorological characteristics over the plantation canopy.

Based on the eddy-covariance system monitoring during leaf germination (15th March to 15th April 2015) and leaf forming (15th July to 15th August), the turbulence characteristics, turbulence intensity, normalized standard variance of turbulent wind speed and bulk transfer coefficient over forest plantation canopy in the Xiaolangdi Ecosystem Location Research Station were analyzed, aiming to deepen the understanding of the micro-meteorological characteristics of the forest ecosystem and provide scientific basis for the further studies of energy balance and material exchange. Results showed that turbulence spectrum of the plantation had a peak frequency in the low frequency zone and the inertial subarea had an obvious dissipation tendency, which was basically in accor-dance with the law of -5/3. Turbulence intensity was significantly affected by canopy structure. When the turbulence was strong, the wind speed was less than 3 m·s-1 in spring and less than 2 m·s-1 in summer. Normalized standard variance of turbulent wind speed in horizontal direction was better than that in vertical direction, which conformed to the similarity law of 1/3 power. The ratio of normalized standard deviation and the friction velocity in u, v, w components of canopy wind speed was 2.55, 2.06 and 1.30 in spring, 2.61, 2.45 and 1.21 in summer, respectively. The bulk transfer coefficient decreased with the increases of stability, with a difference of 1-2 orders of magnitude or more between unstable and stable conditions. Canopy structure had direct influence on the turbulence of the wind speed in each direction, and thereby changed the diffusion direction of the canopy material and energy.

Differences in leaf thermoregulation and water use strategies between three co-occurring Atlantic forest tree species.

In the first study of leaf energy balance in tropical montane forests, we observed current leaf temperature patterns in the Atlantic forest, Brazil, and assessed whether and why patterns may vary among species. We found large leaf‐to‐air temperature differences that were influenced strongly by radiation and differences in leaf temperature between 2 species due to variation in leaf width and stomatal conductance. We highlight the importance of leaf functional traits for leaf thermoregulation and also note that the high radiation levels that occur in montane forests may exacerbate the threat from increasing air temperatures.

Energy Balance and Power Loss Pathway Study of a 120 cc Four-Stroke Internal Combustion Engine

Efforts to improve the range and endurance of group 2 (10–25 kg), internal combustion engine (ICE) powered unmanned aerial vehicles (UAVs) have been underway for several years at Air Force Research Laboratory (AFRL). To obtain the desired performance improvements, research into improving the overall efficiency of the ICE powerplants is of great interest. The high specific energy of hydrocarbon fuels (13,000 W h/kg for gasoline), but low fuel conversion efficiency for small ICEs means that relatively minor improvements in the fuel conversion efficiency of the engines can yield large improvements in range and endurance. Little information is available however for the efficiency of ICEs in the size range of interest (10–200 cm3 displacement volume) for group 2 UAVs. Most of the currently available efficiency data for 10–200 cm3 ICEs is for two-stroke engines. The goal of this study was to provide an in-depth probe of the efficiency and energy losses of a small displacement four-stroke engine which could potentially be used to power a group 2 UAV. Energy balances were performed on a Honda GX120 four-stroke engine using empirical research methods. The engine was a 118 cm3 displacement, single cylinder ICE. Energy pathways were characterized as a percentage of the total chemical energy available in the fuel. Energy pathways were characterized into four categories: brake power, cooling load, exhaust sensible enthalpy and incomplete combustion. The effect of five operating parameters was examined in the study. Fuel conversion efficiency ranged from 22.2% to 25.8% as engine speed was swept from 2000 to 3600 RPM, from 20.8% to 27.3% as equivalence ratio was swept from 0.85 to 1.25, and from 15.7% to 24.9% as throttle was swept from 28.5% to 100%. Combustion phasing and cylinder head temperature sweeps showed only minor changes in fuel conversion efficiency.

Obese Mice Are Protected From Increased Energy Intake in Response to Voluntary Wheel Running

Diseases of metabolism pose an increasing threat to public health that has led to greater demand for effective treatments. Obesity is a highly prevalent metabolic disease that afflicts over 100 million Americans and increases the risk of developing diabetes and cardiovascular disease. Lifestyle modifications that incorporate exercise are a standard prescription for obesity, but its effectiveness is limited due to variability in compliance and physiological adaptations (e.g. compensatory increases in energy intake). Previous studies have shown that voluntary exercise fails to induce weight loss in high fat fed mice, but little is known regarding the onset of exercise. Here, we tested the hypothesis that chronic overnutrition from high fat feeding will mitigate the compensatory increase in food intake that commonly accompanies increased energy expenditure from voluntary exercise.Starting at 12 weeks of age, male C57BL/6J mice were weight matched, singly housed and fed a chow (n=8) or high fat diet (HFD; 60% calories from fat; n=6) for 4 weeks. At 18 weeks of age, mice were housed in a Promethion Metabolic Analyzer to measure energy expenditure, food intake and physical activity. Experiments were performed at 21°C with running wheels locked for four days then unlocked for the subsequent nine days. Body composition was assessed both prior to and immediately following indirect calorimetry experiments. Ethoscan (Sable Systems) analysis was performed to examine voluntary wheel running (VWR) distance, duration and speed and measured the time and distance for off‐wheel activities (i.e. roaming and feeding).HF‐fed mice were heavier (WT: 26.9 ± 1.1 vs. HF: 36.8 ± 4.2 g; p &lt; 0.05) and had greater fat mass (WT: 3.5 ± 0.6 vs. HF: 11.1 ± 3.1 g; p &lt; 0.05) than chow‐fed mice prior to energy balance studies. VWR caused a decrease in whole body (WT: −0.3 ± 0.8 vs. HF: −4.0 ± 1.3 g; p &gt; 0.05) and fat mass (WT: 0.3 ± 0.6 vs. HF: −3.0 ± 0.9 g; p &lt; 0.05) in HFD‐fed, but not in chow‐fed mice. VWR distance, duration, and speed were not affected by diet. VWR increased energy expenditure (EE) with both diets equally, but energy intake (EI) only increased in chow‐fed mice. VWR decreased overall off‐wheel activity (OWA) regardless of diet.These data demonstrate that 9 days of VWR cause weight loss in HFD‐fed mice but not mice fed a chow‐diet. Because VWR did not vary between diets, the efficacy of VWR in HFD‐fed mice could instead be attributed to resistance to specific behavioral compensations (i.e. increased food intake) that occur with the introduction of VWR in lean mice.Support or Funding InformationDSL (16POST29910001); D.H.W. (NIH DK054902 and DK076169)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Fluxo de calor no solo modelado a partir de dados de temperatura em dois níveis de profundidade em uma floresta tropical na Amazônia Ocidental

The global climate is dependent of ecological balance of forests, especially tropical. The heat flux in the soil is an important factor in studies of energy balance representing the main form of energy exchange between soil and atmosphere. The aim of the present work was to estimate soil heat flux using soil temperature measurements at two depth levels in a tropical forest in the Western Amazon, in order to obtain coherent data for both the use of the values and for the filling of failures in database. Had been used data on temperature and soil heat flux collected in a micrometeorological tower belonging to the towers network of the Large Scale Biosphere-Atmosphere Program in the Amazon, located in the Jaru Biological Reserve. The estimated data presented 94% agreement with the measured data, the two have similar behaviors that allow the use in filling of failures in a demonstrative way. However, there is a delay in the estimated values of the heat flux in the soil in relation to the measured one, which interferes in the result of the model, provoking more studies to improve it.