Ratio Energy Balance Research Articles

Observational study on the surface radiation budget and energy balance closure of grassland in the eastern arid region of Northwest China

Based on the observation data of the meteorological environment monitoring system (QT-1010) and the open vorticity correlation system (LI-7500DS), we used the block aerodynamics and energy balance ratio method to analyze the surface radiation budget and energy balance closure characteristics of the grassland in the eastern arid region of Northwest China at different time scales.We found that (1) The daily variation curve of the surface radiation flux is unimodal, and the variation amplitude of each component is as follows: Rs↓> RL↑> RL↓> Rs↑. (2) The monthly peak of each radiation component occurs in summer, and the time of reaching the peak of different components has a lag. The changes of radiation components in sunny and cloudy days are multi-modal. In the precipitation weather, the fluctuation of each radiation flux is unimodal.The average annual surface albedo () is 0.24, which is higher in winter than in summer. There is a linear relationship between surface albedo and soil moisture. (3) The Net radiation (Rnet) dominates the sensible heat in spring and the latent heat in summer. H/Rnet and Gn/Rnet are both positive in a day, H/Rnet and LE/Rnet fluctuate wildly before and after sunrise, and Gn is dominant at night. (4) The energy closure is manifested as summer > winter > Autumn > spring, and the energy closure is good throughout the year.

Relationship between fat-free mass index and nutrient intake in protein supplement user among Japanese collegiate soccer athletes.

Protein supplements are widely used by athletes, prompting the scrutiny of their impact on low energy availability. This study investigated whether habitual protein supplement use is linked to physical characteristics and nutrient intake in Japanese university soccer athletes. In addition, an attempt was made to examine the differences in physical characteristics and nutrient intake according to muscle mass in protein supplement users using the fat-free mass index (FFMI), which reflects muscle mass. A dietary survey, physical activity survey, and measurement of the physical characteristics of 38 Japanese collegiate soccer players were conducted. The habitual protein supplement utilization rate among the participants was 50%, and the participants exhibited an FFMI of 19.2 ± 1.3 kg/m2. Significant disparities between the two groups were noted in exercise energy expenditure (p = 0.023); carbohydrates (p = 0.039); copper (p = 0.003); and vitamins B1 (p = 0.016), B2 (p = 0.040), B6 (p = 0.003), C (p = 0.012), and D (p = 0.033), with higher levels observed in the protein-consuming cohort compared to the non-consuming cohort. Protein supplement users (n = 15) were stratified into two groups based on the median FFMI of the entire population (18.9 kg/m2). While the energy balance ratios were comparable between the groups, the high FFMI group tended to exhibit elevated energy intake (p = 0.169), consumption (p = 0.076), and carbohydrate consumption (p = 0.092), compared to the low FFMI group. These findings suggest that adequate carbohydrate and protein intakes are crucial for preserving or augmenting muscle mass in young Japanese soccer athletes, including those consuming protein supplements.

Intercomparison of sensible and latent heat flux measurements from combined eddy covariance, energy balance, and Bowen ratio methods above a grassland prairie

We present a comparison of four different methods of measuring sensible (H) and latent (LE) heat fluxes for a year over a mixed grass prairie ecosystem in the Nebraska SandHills [eddy covariance (EC), energy balance/Bowen ratio (EBBR), residual energy (RES), modified Bowen ratio (MBR) methods]. Additionally, we developed a set of quality control criteria for each method and present a simplification to the traditional EBBR setup. Using EC as reference, all methods yielded similar estimates of yearly H (regression slopes (m) ~ 2% from unity; HEC > HEBBR, HRES, and HMBR). For yearly LE, EBBR and RES yielded similar estimates with EC (m ~ 2% from unity; LEEC < LEEBBR and LERES), while a larger bias was found from MBR (m ~ 8% from unity; LEEC > LEMBR). At shorter time scales (~ hourly), moderate scatter was found about linear regression fits for H between EBBR and EC (R2 = 0.81), with smaller scatter between RES and MBR, and EC (R2 = 0.91). For LE, smaller scatter was also measured between EC, and EBBR and RES (R2 = 0.89 and 0.87, respectively), with the larger scatter between EC and MBR (R2 = 0.65). This suggests methods other than EC may be well suited to longer-term applications (≥ yearly), but have larger uncertainty on individual measurements.

A preliminary observational study on the characteristics of surface turbulent fluxes over the South China Sea Islands

AbstractIn recent years, there has been a rise in human activities in oceanic areas, making the land–atmosphere interactions over islands a major scientific concern on a global scale. Examining the observation data from offshore areas enables a more comprehensive understanding of the turbulent fluxes in offshore atmospheric environments, patterns of momentum, energy and material exchange between the atmosphere and underlying surface in an oceanic boundary layer, and development of a heterogeneous atmospheric boundary layer. The related findings will assist in developing theoretical models and parameterization schemes to simulate the influence of heterogeneous surfaces on land–atmosphere interactions on the South China Sea Islands. Existing studies on the turbulent fluxes over the South China Sea Islands were mainly conducted on the Nansha Islands, whereas studies on the waters of the South China Sea are scarce. In this study, we used 10 Hz high‐frequency turbulence measurements to calculate the latent and sensible heat fluxes over the South China Sea Islands using the eddy correlation method. These findings were then compared with data from the Dunhuang Gobi, Ordos desert, and Xilingol grassland regions in inland China, along with the observed net radiation and surface heat fluxes. The findings indicate that the energy fluxes over the South China Sea in summer exhibit prominent diurnal variations. The magnitude of either latent or soil heat flux is low, and the net radiation is predominantly transformed into sensible heat flux, which warms the atmosphere. Furthermore, the daily variation curves of sensible and latent heat fluxes are influenced by intermittent turbulence on the islands and reefs, resulting in a less smooth pattern compared with soil heat flux. Although the South China Sea Islands have small land areas and are surrounded by the sea, the land–atmosphere interactions over the underlying surface of this region are similar to those over the underlying surface of grasslands in inland China during summer. The daily mean sensible heat flux on the islands is higher than that in an inland area, and the time lag in its response to sunrise is longer than that in inland areas by approximately 1 h. The overall energy balance ratio is approximately 0.75, c which is in line with the average level, but an energy balance residual of approximately 25% still exists. Furthermore, extreme weather conditions, such as typhoons, can disrupt the diurnal variations of sensible and latent heat fluxes, and the cyclical patterns are subsequently restored.

Environmental, energy, and economic assessment of Jatropha curcas L. biodiesel production in China

Developing non-grain forestry woody fuel industries such as Jatropha curcas L. (JCL) aligns with the national conditions of countries with food shortages and large populations, such as some countries in Africa and Asia, and is an ideal alternative to replace fossil fuels. Determining appropriate planting densities suitable for different regions is one of the most critical practices for agriculture and forestry to achieve high yields and sustainability. This study conducted a life cycle assessment (LCA) of the JCL biodiesel's environmental impact, energy balance, and economic analysis (3E) of two densities and three of the most suitable planting regions in China. Findings reveal that the density of 2500 plants/ha had a better 3E performance than 1600 plants/ha, and Yunnan province outperformed Guizhou province and Sichuan province. JCL biodiesel effectively mitigates the greenhouse effect (1141.14–1936.59 kg CO2 eq/t) compared to conventional fossil diesel in different cases. Key factors influencing environmental performance include seed yield, urea applied during cultivation, methanol for biodiesel conversion, and electricity for irrigation. The Net Energy Balance (NEB) and Net Energy Ratio (NER) demonstrate the superior energy efficiency of JCL biodiesel over fossil diesel. The cost of producing JCL biodiesel decreased with the maturation of the trees, with water use and labor salary accounting for over 80% due to the necessity of the cultivation stage. Although the Financial Net Present Value (FNPV) was negative when considering only JCL biodiesel, it became positive (12111.64–27342.44 CNY) with the inclusion of by-products (glycerine, press-cake, and shells) in high-density cases. Our findings suggest that JCL biodiesel with appropriate density can serve as a sustainable biofuel alternative, replacing a portion of the fossil diesel currently on the market and significantly contributing to climate change mitigation and nonrenewable energy conservation.

Experimental investigation and optimization of heat pipe heat exchanger performance under two distinct heat transport mediums through TOPSIS approach

This paper presents a comprehensive thermal performance analysis of the heat pipe heat exchanger by varying the input process parameters and optimizing the best condition for waste heat recovery through the TOPSIS technique. In this work, the heat pipe is constructed with a copper tube and segmented into evaporator and condenser sections carrying hot and cold fluids with a half-fill ratio. The heat pipe is oriented in 0° horizontally with the wick material made from stainless steel and works based on the capillary principle. The efficiency of the HPHE is evaluated by varying the input operational parameters, namely heat input, mass flow rate of hot fluid, inlet temperature of hot fluid, and mass flow rate of cold fluid, on response variables, specifically thermal resistance, energy balance ratio, universal heat transfer coefficient, and effectiveness. The experiment was designed for four factors at three levels as per Taguchi’s L27 orthogonal array, and the best optimising condition was determined by employing the multi-objective technique for order preference by similarity to ideal solution (TOPSIS) approach. The best input condition found was A3B1C1D3, in which the heat input was at 90 W, the mass flow rate of hot fluid was at 0.2 kg min−1, the mass flow rate of cold fluid was at 0.1 kg min−1, and the inlet temperature was at 60 °C. The effect of process parameters and their significance on output responses was analysed by executing an analysis of variance (ANOVA) statistical method. The mathematical regression model was generated, and validation was made to investigate the prediction error percentage.

Abstract P190: Association of Meal Timing With Measures of Obesity: The Hispanic Community Health Study/Study of Latinos

Introduction: Time-restricted feeding has been associated with healthier weight, and as a weight-control intervention, can reduce caloric intake without calorie counting. Previous research showed that individuals with overweight who shortened their eating duration (time between first and last food intake of the day) experienced beneficial weight reduction. We explored this association in understudied US Hispanic/Latino individuals, as they experience a high prevalence of overweight and obesity. Hypothesis: We assessed the hypothesis that shorter eating duration is associated with healthier body mass index (BMI), percent body fat, or waist to hip ratio. Methods: We analyzed cross-sectional data from n=12079 Hispanic/Latino participants from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) who were not pregnant, not underweight, had reliable 24-hour dietary recall data, and had at least 3 accelerometer wear days. For each participant, we calculated eating duration, defined as the time between the first and last food intake of the day averaged over two 24-hour dietary recalls. We modeled eating duration in hours as the primary exposure in linear regression models with baseline measured BMI, percent body fat, or waist to hip ratio as outcomes of interest. We adjusted for age, sex, Hispanic background, field center, socioeconomic factors, sleep duration, glycemic status, diet quality, measured physical activity, and energy balance (ratio of energy intake to estimated energy needs). BMI was log transformed to help meet assumptions. Analyses accounted for complex survey design, missing accelerometer data, and accelerometer wear time. Results: Mean (SE) eating duration was 11.9 (0.04) hours. Those with longer eating duration tended to have higher energy intake (though less apparent for those with BMI at least 30), spend more time in moderate or vigorous physical activity, and were more likely to be employed full-time and perform shift work. After adjusting for energy balance and socioeconomic, medical and lifestyle factors, we found a significant positive association between eating duration and log-transformed BMI (regression coefficient 0.003 for eating duration in hours, SE 0.001, p=0.02). This significant association emerged only after adjusting for energy balance, demonstrating the importance of controlling for confounding between eating duration and intake. In sensitivity analysis, we excluded those with prevalent heart disease or diabetes, and obtained similar results. No statistically significant associations were noted between eating duration and the other obesity measures. Conclusions: Longer eating duration was associated with higher BMI in Hispanic/Latino persons after adjusting for covariates and energy balance from self-reported intake.

Characterizing energy balance closure over a heterogeneous ecosystem using multi-tower eddy covariance

Single point eddy covariance measurements of the Earth’s surface energy budget frequently identify an imbalance between available energy and turbulent heat fluxes. While this imbalance lacks a definitive explanation, it is nevertheless a persistent finding from single-site measurements; one with implications for atmospheric and ecosystem models. This has led to a push for intensive field campaigns with temporally and spatially distributed sensors to help identify the causes of energy balance non-closure. Here we present results from the Chequamegon Heterogeneous Ecosystem Energy-balance Study Enabled by a High-density Extensive Array of Detectors 2019 (CHEESEHEAD19)—an observational experiment designed to investigate how the Earth’s surface energy budget responds to scales of surface spatial heterogeneity over a forest ecosystem in northern Wisconsin. The campaign was conducted from June–October 2019, measuring eddy covariance (EC) surface energy fluxes using an array of 20 towers and a low-flying aircraft. Across the domain, energy balance residuals were found to be highest during the afternoon, coinciding with the period of surface heterogeneity-driven mesoscale motions. The magnitude of the residual varied across different sites in relation to the vegetation characteristics of each site. Both vegetation height and height variability showed positive relationships with the residual magnitude. During the seasonal transition from latent heat-dominated summer to sensible heat-dominated fall the magnitude of the energy balance residual steadily decreased, but the energy balance ratio remained constant at 0.8. This was due to the different components of the energy balance equation shifting proportionally, suggesting a common cause of non-closure across the two seasons. Additionally, we tested the effectiveness of measuring energy balance using spatial EC. Spatial EC, whereby the covariance is calculated based on deviations from spatial means, has been proposed as a potential way to reduce energy balance residuals by incorporating contributions from mesoscale motions better than single-site, temporal EC. Here we tested several variations of spatial EC with the CHEESEHEAD19 dataset but found little to no improvement to energy balance closure, which we attribute in part to the challenging measurement requirements of spatial EC.

A dataset of carbon and water fluxes of the typical grasslands in Duolun County, Inner Mongolia during 2006-2015

Grassland is an important terrestrial ecosystem for the exchange of mass and energy between land and atmosphere, playing an important role in global carbon cycle. However, the direction and size of its carbon sink are still in dispute. The eddy covariance technique can be sued to continuously determine ecosystem-level carbon, water and energy exchanges between vegetation and atmosphere. The long-term observations of carbon and water fluxes can help quantify the carbon sequestration capability of grassland ecosystems and its response to climate change. This dataset consists of two half-hourly data files, including the carbon, water and heat fluxes data file and the meteorological variables data file. All of the flux data were processed according to the flux data processing procedure specified by ChinaFLUX. The observational quality of this dataset is good, with a complete data observation integrity of over 95% throughout the year and a high energy balance ratio (1.04 ± 0.07). This decadal flux dataset from 2006 to 2015 provides a high-quality and continuous long-term eddy flux observation data valuable for the research of diurnal dynamics, seasonal and interannual variations of carbon and water fluxes, which is significant for evaluating the role of China’s temperate typical grasslands in regional and global carbon and water cycles.

Ground‐based infrared thermometry reveals seasonal evapotranspiration patterns in semiarid rangelands

AbstractDetailed assessment of small‐scale heterogeneity in local surface water balance is essential to accurate estimation of evapotranspiration in semiarid climates. However, meteorological approaches are often impractical to implement in sites with sparse and diverse vegetation composition, especially with seasonally variable leaf canopy features. Ground‐based infrared thermometry (TIR) provides spatially and temporally continuous resolution of surface skin temperature that can be directly related to the land surface energy balance. We made repeated measurements with a portable TIR camera to capture seasonal replicates for patch scale heat images for four sagebrush communities. The heat images near peak foliage and near the end of the growing season were compared by computation of surface energy fluxes from TIR sensing to surface energy balance (SEB) and Bowen ratio (BR). Estimates of sensible (H) and latent heat flux (LE) were evaluated with eddy covariance measurements to disaggregate the expression of seasonal phenology of sagebrush species across wetness and elevation. Estimations showed reasonable agreement with ground‐based LE observations for most cases (r2 = 0.59–0.76 for SEB and 0.22–0.72 for BR; root mean squared error = 73.4–106.4 W m−2 for SEB and 109.9–204.0 W m−2 for BR). Predictability declined as the fraction of senescent foliage increased in dry conditions. The field trials suggest the methods have the potential for monitoring land surface energy fluxes and plant health at a very fine spatial scale. The ability to partition heat fluxes from various plant communities over a range of moisture availability will provide valuable information associated with the consumptive water use and phenological processes in the semiarid West.

Parameter variability across different timescales in the energy balance-based model and its effect on evapotranspiration estimation

Evapotranspiration is a key consideration for addressing a number of scientific and engineering issues. There are considerable errors in current evapotranspiration models due to the high uncertainty in model parameters. Considering that evapotranspiration models maintain the same mathematical form when run on different timescales, we argue that the uncertainty in model parameters can be reduced by considering the parameter variability across different timescales. Here, the four key parameters in the energy balance-based evapotranspiration model, including aerodynamic roughness length, thermodynamic roughness length, surface conductance, and energy balance ratio, are retrieved and evaluated on instantaneous and daily timescales based on the observations from 113 sites in the FLUXNET2015 dataset. Then data-driven instantaneous and daily parameter models are built to estimate evapotranspiration. The results show that strong multi-timescale variability occurs in all four parameters. The coefficients of variation of the four instantaneous parameters range from 0.32 to 1.70. The links of parameters on different timescales are weak. The correlation coefficients of the daily mean value of instantaneous parameter values and daily parameter values vary from 0.44 to 0.83. By considering the multi-timescale variability of the parameters, the accuracy of evapotranspiration estimation can be largely improved, with RMSE of the instantaneous and daily evapotranspiration estimation decreasing from 35.76 to 9.52 W m−2 and from 12.01 to 3.01 W m−2, respectively. We also find that the parameter models perform well on their inherent timescales but degrade significantly when transferring to other timescales. This study proves the necessity of defining parameter variability across different timescales in evapotranspiration models and provides new insight into the model parameters.

Sustainability assessment of palm oil-based refinery systems for food, fuel, and chemicals

Palm-based biorefinery system has gained attention worldwide because of potentially high economic returns. However, environmental impacts also increase with the additional production. Therefore, this study aims to assess the sustainability of (1) current palm-based biorefinery system in Thailand, including cooking oil and biodiesel, and (2) palm-based biorefinery system with value-added products, i.e., succinic acid, lactic acid, bio-hydrogenated diesel (BHD), and epichlorohydrin (ECH) that represent biomaterial, biofuel, and biochemical products, respectively. Accordingly, seven palm-based biorefinery scenarios were designed, and their sustainability was assessed through life cycle assessment (LCA), net energy balance (NEB) and net energy ratio (NER), employment generation, and eco-efficiency. The results revealed that value-added production increased global warming impacts by around 3 – 79% compared with the current system. Although environmental impacts increased due to the additional processes related to the production of the value-added products, total product values also increased, especially for succinic acid, generally leading to higher eco-efficiency values. The current palm-based biorefinery system with succinic acid production had the highest eco-efficiency among all the scenarios considered. The BHD production scenario had the highest NEB and NER because the products were used for energy. Employment generation increased for all the scenarios between 2 – 86% compared with the current system.

Characteristics of Energy Distribution in a Desert Ecosystem in Inner Mongolia, Northern China

Desert ecosystems are vulnerable to climate change because of their fragile environment and poor self-regulation ability. Exploring the land–surface energy balance and the water/heat transfer processes of such regions for water resource management purposes is critical. The processes of surface water and heat transfer throughout the desert ecosystems and the effects of environmental factors on the energy distribution remain poorly studied. In this study, we used an eddy covariance system and surface meteorological data (2019–2021) to investigate the characteristics of the energy balance of Dengkou Desert ecosystem located in Inner Mongolia, northern China. Also, we evaluated the effects of different environmental factors on the energy distribution in this desert ecosystem. We found that the temporal patterns of both sensible heat flux (H) and latent heat flux (LE) with time are consistent with that of net radiation (Rn), and Rn is dominated by H. The sum of the daily average soil heat flux during the observation period was positive, indicating that soil was a heat sink and that the atmosphere transfers heat to the soil. During the observation period, the energy distribution of H/Rn fluctuated greatly, presenting a general U-shaped trend, while LE/Rn presented an inverted V-shaped trend. The main factor affecting H was Rn, followed by saturated vapor pressure, air temperature (Ta), and relative humidity. For LE, the main influencing factors were Ta, and Rn. The energy closure of the half-hour flux in the Inner Mongolian desert ecosystem during the observation period was 48%–68%, and the energy balance ratio was 0.54–0.74. The energy closure at the daily scale was higher than that at the half-hour scale, and the energy closure during daytime was higher than that at night.

Evapotranspiration dynamics and their drivers in a temperate mixed forest in northeast China.

Evapotranspiration (ET) is a vital part of the global water cycle and is closely related to carbon sequestration. Analysing ET dynamics and their drivers would benefit for improving our understanding of the global water and carbon cycles. Using an eddy covariance (EC) approach, we analysed ET dynamics and their drivers in a temperate mixed forest over northeast China from 2016 to 2017. The results showed that 43.55% of our eddy covariance data passed the quality control. In addition, the energy balance ratio was 0.62, indicating that measurements were reliable. The measured ET showed clear single peak patterns with seasonal and diurnal variations. The daily ET ranged from 0 to 7.75 mm d−1 and the hourly ET ranged from 0 to 0.28 mm h−1. The ranges of hourly ET floated from 0 to 0.05 mm h−1 at non-growing season (November to April) while ranged from 0 to 0.28 mm h−1 at active growing season (May to October). The diurnal ET dynamics during the non-growing season were driven by air temperature (Ta), but were governed by global radiation (Rg) during the active growing season. Leaf area index (LAI) comprehensively reflected the variations of Ta and Rg, and was found to be the primary factor shaping the seasonal dynamics of ET. The annual ET rates were 501.91 ± 5.30 mm year−1 and 554.60 ± 11.24 mm year−1 for 2016 and 2017, respectively. Therefore, energy supply, represented by Ta and Rg, governed ET dynamics in our temperate mixed forest, while variables representing the energy supply affecting ET dynamics differed among seasons and time scales. ET dynamics indicated that a temperate mixed forest is important to the global water cycle. Our results improved our understanding of ET dynamics in the studied region.

Ammonia Recovery from Wastewater as a Fuel: Effects of Supporting Electrolyte on Ammonium Permeation through a Cation-Exchange Membrane.

Electrodeionization (EDI) is used to recover ammonia from wastewater as a fuel, but how its performance for ammonia recovery is affected by the supporting electrolyte is not very clear. This study involved experimental tests and theoretical calculations on NH3 recovery, NH4+ permeation, and NH4+ and Na+ interacting with the functional groups in a cation exchange membrane (CEM) using Na2SO4 as the supporting electrolyte. The results demonstrated that a low concentration (≤0.250 mol L–1 of Na2SO4) was conducive to NH4+ permeation, while the a concentration (0.750 mol L–1 of Na2SO4) hindered NH4+ permeation. A maximum recovery efficiency of ammonia of 80.00%, a current efficiency of 70.10%, and an energy balance ratio of 0.66 were obtained at 0.250 mol L–1 of Na2SO4. Numerical results indicated that an increase in Na2SO4 concentration caused severe concentration polarization that resisted NH4+ migration in the CEM. The DFT results demonstrated that competitive adsorption of Na+ to the CEM hindered NH4+ migration. The weaker interacting force between NH4+ and the sulfonate functional group (−SOH3) in comparison to that between Na+ and −SOH3 might be related to the geometric and orientation effects, which generated an additional energy barrier for NH4+ transport. Therefore, this study suggests that the supporting electrolyte concentration should be matched with that of the desalted ions.

A Methodology for Providing Surface-Cover-Corrected Net Radiation at Heterogeneous Eddy-Covariance Sites

A one-point measurement of net radiation is typically not representative of radiative energy available for the turbulent exchange of latent and sensible heat at eddy-covariance sites with heterogeneous surface cover. We propose a methodology for providing surface-cover-corrected net radiation matching the footprint of turbulent fluxes at a heterogenous eddy-covariance site. This is demonstrated at a complex sub-alpine site in southern central Norway over a week. The methodology is assessed by comparing the energy balance closure calculated with the regular one-point net radiation measurement at the flux tower against the surface-cover-corrected net radiation. The assessment indicates a decrease in the energy imbalance by 8% when assessed with the energy balance ratio, but no improvement is revealed when assessed with regression methods. However, only a small dataset serves as basis for this demonstration, and the findings therefore cannot necessarily be generalized. Further testing and application of the methodology is required to understand the full effect of surface-cover-correcting mismatching footprints of turbulent fluxes and net radiation at heterogeneous eddy-covariance sites.

Energy Exchange and Evapotranspiration over the Ejina Oasis Riparian Forest Ecosystem with Different Land-Cover Types

Investigating the energy and water vapor exchange in oasis riparian forest ecosystems is of significant importance to improve scientific understanding of land surface processes in extreme arid regions. The Heihe Watershed Allied Telemetry Experimental Research (HiWATER) provided many observations of water vapor and heat fluxes from riparian forest ecosystem by using a network of eddy-covariance (EC) systems installed over representative surfaces in the Ejina Oasis, which is located in the downstream areas of the Heihe River Basin, northwestern China. Based on EC flux measurements and meteorological data performed at five stations and covering representative surface types of Populus euphratica tree with associated Tamarix chinensis shrub, Tamarix chinensis shrubland, cantaloupe cropland, and barren-land, this study explored the spatio-temporal patterns of heat and water vapor fluxes over the Ejina Oasis riparian forest ecosystem with five different surface types over the course of a growing season in 2014. Energy balance closure of the flux data was evaluated; footprint analysis for each EC site was also performed. Results showed that energy balance closure for the flux data was reasonably good, with average energy balance ratio (EBR) of 1.03. The seasonal variations in net radiation (Rn), latent (LE), and sensible heat flux (H) over the five contrasting surfaces were similar, and a reverse seasonal change was observed in energy partitioning into LE and H. Remarkable differences in Rn, LE, and H between the five surfaces were explored preliminarily, associated closely with the soil properties and foliage phenology. Over the growing season (May–October) in 2014, the total ET ranged 622–731 mm for mixed forest of P. euphratica trees with associated T. chinensis shrubs with average daily ET of 3.6–4.2 mm; ET from T. chinensis shrubland was about 541 mm, with average daily ET of 3.6 mm. ET for barren-land was 195 mm. The total ET in irrigated cantaloupe cropland with plastic mulch was 431 mm for its four-month growing period with a total average of 3.8 mm d−1. Determination of ET over riparian forest ecosystem helps to improve reasonable use of limited water resource in the Ejina Oasis.

Energy flux observation in a shrub ecosystem of a gully region of the Chinese Loess Plateau

Flux observations are important for understanding the basic processes of carbon and water cycling in an ecosystem. In 2020 (1 January 2020 to 31 December 2020), we continuously monitored the surface energy fluxes of a shrub ecosystem using an eddy covariance system. Additionally, meteorological variables, such as temperature and rainfall, were measured. The study site was located in Chunhua of China, which is a gully region of the Chinese Loess Plateau. The diurnal and seasonal dynamic changes in the energy balance of this region were analysed, Bowen and energy balance ratios were calculated, and environmental factors affecting the variations in latent (LE) and sensible heat fluxes (H) were explored. The results showed that the annual net radiation (Rn), LE, H, and soil heat flux (G) were 2385.6, 1059.1, 787.6, and - 48.3 MJ/m2, respectively, with 490.58 MJ/m2 energy remaining undetected. The main part of the annual energy of the shrub ecosystem was latent heat, accounting for 44.4% of Rn. A seasonal variation in each energy component was evident, and the diurnal variation showed a single peak curve. LE in the growing season was dominant, and the proportion of LE and H in the net radiation in the non-growing season showed little difference. The Bowen ratio changed monthly and significantly fluctuated from 0.2 in July to 4.0 in December. It was high in winter and low in summer, with little fluctuation. The annual energy balance ratio was 0.8. The energy balance closure in the non-growing season was greater than that in the growing season. Both H and LE were significantly correlated with net radiation, and H was negatively correlated with rainfall, soil moisture, and soil temperature. Unlike H, LE was significantly positively correlated with soil temperature. In addition, LE was positively correlated with air humidity gradient and water vapour pressure difference.

Biorefinery of genetically modified soybean as biodiesel with sustainable production system in Indonesia: A review

Fossil energy consumption in Indonesia is high every year, and this can cause an imbalance between demand and the availability of available fuel. Besides, fossil fuels are also classified as non-renewable fuels, so that the availability of fuel can be used up if exploited continuously. High diesel consumption makes it necessary to search for other energy sources that can be used to meet diesel needs in Indonesia. Alternative diesel replacement that can be used is biodiesel fuel from soybeans. One of the disadvantages of using soy as a biodiesel feedstock is its low oil content. An alternative that can be done is by using genetically modified (GM) soybeans that have higher oil content. The biorefinery approach can also be carried out as an effort to make biodiesel production sustainable, both economically and environmentally. GM soybean can be assembled through several stages, which are selection of varieties, assembly of GM soybean, and then testing and licensing. After that, soybeans can be used and utilized in the Indonesian market. The biodiesel production system from GM soybeans using a biorefinery approach is carried out by utilizing residues during production into other products so that it can be an additional income, and reduce the impact of environmental pollution. A high net energy balance ratio (NER) in some biodiesel production from soybeans makes biodiesel production from soybeans can be said to be renewable and economically sustainable. Biodiesel production from GM soybeans with the concept of biorefinery has the opportunity to become a sustainable industry, both economically and environmentally.

Finite Element Bus Rollover Test Verification

&#x0D; &#x0D; &#x0D; This study is conducted to verify the rollover test of the finite element bus model. Verification is a process of determining that a computational model accurately represents the theoretical mathematical model and its solutions. In case of bus rollover simulation, the verification process is by looking into its energy balance, in which all energy associated with the bus rollover process must be equal and preserved before and after the rollover. Any energy imbalance indicates errors in the rollover process and must be rectified so that the errors remain in acceptable tolerance. The main energies involved in calculations are potential energy, kinetic energy, internal energy, contact energy, rigidwall energy, damping energy, hourglass energy, and total energy. The finite element bus model used is CONTRAST bus developed by CM/E Group, Politecnico di Milano. The rollover test standard used is UN R66, and the software used to set up and solve the simulation are LS-PrePost and LS- DYNA. Energy balance and energy ratio from the rollover simulation shows that the verification procedure is followed, results are within acceptable values, and the rollover test is verified.&#x0D; &#x0D; &#x0D;