Gas Loss Research Articles

Environmental impact assessment of an air-to-water heat pump through the expanded total equivalent warming impact index based on experimental data

The Total Equivalent Warming Impact (TEWI) index is conventionally used to evaluate emissions from heating, ventilation, air conditioning and refrigeration (HVAC&R) systems. However, a more comprehensive indicator, the Expanded Total Equivalent Warming Impact (ETEWI), has been proposed to overcome the limits of TEWI index and to consider additional environmental impacts such as the effects of urban heat island and the natural gas losses along high-pressure pipelines supplying gaseous fuel to natural gas-fired power plants. In this study, TEWI and ETEWI metrics are applied to an air-to-water electric heat pump (EHP) serving a university building in Benevento (Southern Italy). Real data on EHP electricity consumption have been derived from the entire building's electric load and compared to measured data. ETEWI index has been estimated in two scenarios, one considering the impact of refrigerant charge variation on the performance of the EHP and its environmental impact and the other disregarding it. Additionally, carbon dioxide emission factors for electricity production have been forecasted from 2021 to 2033 to determine the indirect term of ETEWI index. Over the lifetime of the EHP, ETEWI increases by 4.8% compared to TEWI when the variation of refrigerant charge level is not considered. However, this percentage growth is equal to 6.5% when the impact of refrigerant charge change is accounted too. In the latter scenario, the indirect term of ETEWI decreases from 22.7 tCO2 in 2015 to 12.0 tCO2 in 2033 when the forecast of the carbon dioxide emission factors for electricity production is taken into account.

Cactus pear mucilage processing enhances corn silage's quality, ruminal degradability, goat kids' performance, carcass traits, and dietary economic profitability

The objective of this study was to evaluate the effects of different moisture additives to ground corn grain silage on silage quality, performance, and carcass characteristics of goat kids, and the economic efficiency of the diets. The experimental silos were opened 90 days after silage making and analyzed for chemical composition and aerobic stability. Two experiments were carried out simultaneously, one with 32 non-castrated crossbred male Boer goat kids, weighing on average 16.4 ± 2.5 kg at 6 months of age distributed in a randomized block design with four treatments and eight replications to evaluate performance, carcass characteristics and economic efficiency of the diet; the other with four male sheep weighing 30.4 ± 6.0 kg, fistulated and cannulated in the rumen, and distributed in a Latin square design (4 × 4) to evaluate the rumen degradability profile of the diets. The experimental treatments were a control diet with ground corn grain (GC) and three corn grain silages rehydrated with moisture additives: water (RCSwater), cactus pear cladode mucilage (RCSmucilage) and whey (RCSwhey). The evaluation of the chemical composition of the silages showed that the highest DM, NDF and ash contents were in RCSmucilage, while the lowest was in RCSwater (P < 0.0001), and that there was no difference in NDF content between RCSwhey and RCSwater (P > 0.05). Silage pH was higher for RCSwater and did not differ between RCSmucilage and RCSwhey, while N-NH3 content was lower in RCSmucilage and higher in RCSwater and RCSwhey (P < 0.05). CP, lignin, effluent losses, gas losses, dry matter recovery, lactic acid and propionic acid contents did not differ among silages (P > 0.05). However, acetic acid presented a higher concentration (P < 0.05) in RCSmucilage and lower in RCSwhey. DM and NDF intake, ADG, slaughter weight, total income from carcass sales and income over dietary costs were higher for RCSmucilage when compared to the other silages, and like the control treatment. There was no effect of diets on metabolizable energy and CP intake, feed efficiency, hot and cold carcass weight and yield, cooling losses, loin eye area, and subcutaneous fat thickness of the goat kids carcasses (P > 0.05). The total replacement of ground corn grain in the concentrate by RCSmucilage is recommended in the diet of goat kids, since it promotes better silage conservation, increases DM intake and weight gain, and provides better financial income.

Activating Mn Redox for Boosting Performance Enabled by Highly Oxidized Ru in a P2-Type Cathode Material for Sodium-Ion Batteries

To overcome the inherent limitations of sodium-ion batteries (SIBs) such as relatively low energy density and operating voltage compared to lithium-ion batteries (LIBs), Oxygen redox chemistry is considered to realizing a high-performance battery system. However, oxygen redox commonly accompanied problems such as sluggish kinetics, O2 gas loss, and irreversible structural rearrangement with voltage hysteresis. Herein, we suggest a new model that deviates from the tendency of relying on oxygen redox reaction to realize high capacity. A deep investigation of Na0.6Mg0.2Mn0.8O2 (NMM) and Na0.6Mg0.2Ru0.2Mn0.6O2 (NMRM) is conducted by various analysis tools for the comparison. The highly oxidized Ru5+ lowers the Mn oxidation state in the structure without the Jahn-Teller effect. It drives the increased participation of Mn in the overall electrochemical reaction and the charge compensation by oxygen redox reaction is mostly replaced by the Mn3+/Mn4+ redox pair. A strong covalence of Ru stabilizes the structure and prevents cation migration from TM to Na slap. As a result, even though the specific weight increased, practical capacity was improved by maximizing the participation of Na+ ions, and we confirm that cyclability and rate capability also improved.

Effects of five-year field aged zeolite on grain yield and reactive gaseous N losses in alternate wetting and drying paddy system

Clinoptilolite zeolite has been widely used in agricultural production systems for enhancing water and fertilizer savings, mitigating greenhouse gas emissions, and increasing yield. However, there is little information on field-aged effects of zeolite on reactive gaseous N losses under alternate wetting and drying irrigation (AWD). We conducted a five-year field experiment to investigate field-aged effect of natural zeolite addition at 0 (Z0), 5 (Z5), and 10 (Z10) t ha−1 on reactive gaseous N losses (NH3, N2O), N-related global warming potential (GWPN), soil properties and grain yield under two irrigation regimes (CF: continuous flooding irrigation; AWD) in the 4th (2020) and 5th (2021) years since its initial application in 2017. As compared with CF, AWD did not significantly affect grain yield and NH3 volatilization but increased seasonal N2O emissions by 46 %–71 % over two years. Zeolite increased rice yield for five consecutive years. Z10 reduced averaged cumulative NH3 volatilization and GWPN by 23 % and 26 %, compared to zeolite-free treatment, respectively, in the 4th and 5th years. Soil NH4+-N was increased with the increased rate of Z application under both CF and AWD. Z10 increased soil NH4+-N by 27 %–38 % and NO3−-N by 14 %–22 % in five years, compared to Z0, respectively. Compared to AWD without zeolite, the addition of 10 t ha−1 zeolite under AWD lowered NH3 volatilization, cumulative N2O emissions, and GWPN by an average of 28 %, 29 %, and 30 % in two years, respectively. IAWDZ10 did not differ from ICFZ0 on reactive gaseous N losses but significantly lowered reactive gaseous losses relative to IAWDZ0. Therefore, zeolite addition could mitigate the reactive gaseous N losses and GWPN for at least five years after initial application, which is beneficial to promoting zeolite application and ensuring sustainable agriculture.

Carbon and nutrient pools and fluxes in unmanaged mountain Norway spruce forests, and losses after natural tree dieback

Forest areas infected by insects are increasing in Europe and North America due to accelerating climate change. A 2000–2020 mass budget study on major elements (C, N, P, Ca, Mg, K) in the atmosphere-plant-soil-water systems of two unmanaged catchments enabled us to evaluate changes in pools and fluxes related to tree dieback and long-term accumulation/losses during the post-glacial period. A bark-beetle outbreak killed >75 % of all trees in a mature mountain spruce forest in one catchment and all dead biomass was left on site. A similar forest in a nearby catchment was only marginally affected. We observed that: (1) the long-term (millennial) C and N accumulation in soils averaged 10–22 and 0.5–1.1 kg ha−1 yr−1, respectively, while losses of Ca, Mg, and K from soils ranged from 0.1 to 2.6 kg ha−1 yr−1. (2) Only <0.8 % and <1.5 % of the respective total C and N fluxes entering the soil annually from vegetation were permanently stored in soils. (3) The post-disturbance decomposition of dead tree biomass reduced vegetation element pools from 27 % (C) to 73 % (P) between 2004 and 2019. (4) Tree dieback decreased net atmospheric element inputs to the impacted catchment, and increased the leaching of all elements and gaseous losses of C (∼2.3 t ha−1 yr−1) and N (∼14 kg ha−1 yr−1). The disturbed catchment became a net C source, but ∼50 % of the N released from dead biomass accumulated in soils. (5) Despite the severe forest disturbance, the dissolved losses of Ca and Mg represented 52–58 % of their leaching from intact stands during the peaking atmospheric acidification from 1970 to 1990. (6) Disturbance-related net leaching of P, Ca, Mg, and K were 4, 69, 16, and 114 kg ha−1, respectively, which represented 7–38 % of the losses potentially related to sanitary logging and subsequent removal of the aboveground tree biomass.

A new look at the sorption kinetics in reference gas standards

The preparation of calibration gas mixtures in cylinders using the gravimetric method (ISO 6142-1) has enabled the production of a wide range of mixtures down to the pmol/mol level with low uncertainties reaching 0.01% relative and beyond. The gravimetric method has limited use however for reactive components that adsorb on the cylinder wall or valve. For such components the adage ‘what comes in = what comes out’ no longer holds. To quantify gas losses in cylinders due to adsorption on the inner surfaces, two methods are typically used: by comparison against other gas mixture preparation methods (e.g. dynamic methods) or by decanting part of a mixture in an identical cylinder followed by cross-comparison. Here we present a new method to elucidate the sorption dynamics based on the use of isotopes (here 12C-methanol and 13C-methanol isotopes). The amount fraction evolution of both isotopes in gas phase is followed in time using laser spectroscopic methods. This way, the kinetics of desorption (mainly 13C-methanol) and adsorption (12C-methanol) can be followed in time. In this paper we will present the results from a pilot study on methanol mixtures at trace amount fractions prepared in different cylinder materials and treatments.

Experimental and numerical studies of thermal power conversion and energy flow under high-compression ratios of a liquid methane engine (LME)

To improve the performance of a liquid methane engine (LME) under universal characteristics, the in-cylinder combustion process and thermal power conversion under different compression ratios were studied by experiment. The experimental results show that increasing the compression ratio results in a linear increase in EEE (effective expansion efficiency) and EER (effective expansion ratio). Moreover, the thermal efficiency varies significantly with the compression ratio only at low and medium loads. The effective thermal efficiency can reach up to 48.69%. For high-speed conditions, it is recommended to reduce friction losses and pump gas losses. Furthermore, a 1-D simulation model was developed to simulate the in-cylinder energy flow with a compression ratio of 12.6. The simulation results show that exhaust timing has a more pronounced effect on the in-cylinder energy flow (thermal balance) than intake timing. When the engine speed is 800 rpm, advancing the exhaust timing by 20°CA can increase the effective thermal efficiency by about 1%.

A New Method for Comprehensive and Quantitative Characterization of Shale Microfractures: A Case Study of the Lacustrine Shale in the Yuanba Area, Northern Sichuan Basin

Microfractures can connect isolated pores within shale, significantly increasing the shale’s storage capacity and permeability, and benefiting shale gas exploitation. Therefore, the quantitative characteristics of microfractures are important parameters for shale reservoir evaluation. In this paper, taking the Jurassic Da’anzhai Member (J1z4) lacustrine shale in the Yuanba area of the northern Sichuan Basin as an example, we propose a method for comprehensive and quantitative characterization of shale microfractures that combines rock thin section (RTS) and scanning electron microscopy (SEM) observations. The different magnifications of RTSs and SEM images lead to the identification and characterization of microfractures of different scales using these two methods. RTSs are mainly used to characterize microfractures with widths larger than 10 μm, while SEM is mainly used to characterize microfractures with widths smaller than 10 μm. These techniques can be combined to comprehensively and quantitatively characterize microfractures of different scales in shale. The microfracture characterization results show that the average total porosity of the J1z4 shale is 4.46%, and the average microfracture surface porosity is 1.20% in the Yuanba area. The calculated average percentage of microfracture porosity to total porosity is 21.09%, indicating that the J1z4 shale reservoir space is dominated by pores and has the conditions for stable shale gas production and potential for shale gas exploration. However, the percentage of microfracture porosity to total porosity of shale near faults and fold zones approaches or exceeds 50%, which may lead to the loss of shale gas. The new method proposed in this study is also useful for quantitative characterization of shale microfractures in the Sichuan Basin and other basins.

Effects of hotter, drier conditions on gaseous losses from nitrogen fertilisers

Global warming is expected to cause hotter, drier summers and more extreme weather events including heat waves and droughts. A little understood aspect of this is its effects on the efficacy of fertilisers and related nutrient losses into the environment. We explored the effects of high soil temperature (>25 °C) and low soil moisture (<40% water filled pore space; WFPS) on emissions of ammonia (NH3) and nitrous oxide (N2O) following application of urea to soil and the efficacy of urease inhibitors (UI) in slowing N losses. We incubated soil columns at three temperatures (15, 25, 35 °C) and three soil moisture contents (20, 40, 60% WFPS) with urea applied on the soil surface with and without UIs, and measured NH3 and N2O emissions using chambers placed over the columns. Four fertiliser treatments were applied in triplicate in a randomised complete block design: (1) urea; (2) urea with a single UI (N-(n-butyl) thiophosphoric triamide (NBPT); (3) urea with two UI (NBPT and N-(n-propyl) thiophosphoric triamide; NPPT); and (4) a zero N control. Inclusion of UI with urea, relative to urea alone, delayed and reduced peak NH3 emissions. However, the efficacy of UI was reduced with increasing temperature and decreasing soil moisture. Cumulative NH3 emission did not differ between the two UI treatments for a given set of conditions and was reduced by 22–87% compared with urea alone. Maximum cumulative NH3 emission occurred at 35 °C and 20% WFPS, accounting for 31% of the applied N for the urea treatment and 25%, on average for the UI treatments. Urease inhibitors did not influence N2O emissions; however, there were interactive impacts of temperature and moisture, with higher cumulative emissions at 40% WFPS and 15 and 25 °C accounting for 1.85–2.62% of the applied N, whereas at 35 °C there was greater N2O emission at 60% WFPS. Our results suggest that inclusion of UI with urea effectively reduces NH3 losses at temperatures reaching 35 °C, although overall effectiveness decreases with increasing temperature, particularly under low soil moisture conditions.

Revealing steam temperature characteristics for a double-reheat unit under coal calorific value variation

Currently, the severe fluctuation of steam temperature in double-reheat (DR) ultra-supercritical (USC) units has become a major problem that constrains their efficient and flexible operation, wherein the deviation of coal calorific value from the design value is one of the major reasons for this issue. However, the effect of coal calorific value variation on the steam temperature characteristics during the flexible operation of DR USC units remains unclear. A dynamic model of a 1000 MW DR USC unit is developed with primary principles and validated with real operation data. The effect of the coal calorific value variation on the steam temperature characteristics is revealed. Results show that as the calorific value of the coal increases, the main steam temperature can always maintain at the design value with attempering water adjustments, while the two reheat steam temperatures decrease. The steady-state deviations of the reheat steam temperatures are positively correlated with the magnitude of the coal calorific value variation, where the deviation of the secondary reheat steam temperature is larger. Meanwhile, as the load increases, the steady-state deviations of reheat steam temperatures increase, but the response time decreases. Finally, the effect of calorific value variation on the boiler efficiency is studied. As the coal calorific value increases, the boiler efficiency firstly rises caused by the decrease in the loss of the flue gas and then falls caused by the limited furnace temperature increase. This study provides guidance on the DR USC boiler operation under coal variation.

Jellyfish galaxies with the IllustrisTNG simulations – when, where, and for how long does ram pressure stripping of cold gas occur?

ABSTRACT Jellyfish galaxies are prototypical examples of satellite galaxies undergoing strong ram pressure stripping (RPS). We analyse the evolution of 512 unique, first-infalling jellyfish galaxies from the TNG50 cosmological simulation. These have been visually inspected to be undergoing RPS sometime in the past 5 Byr (since z = 0.5), have satellite stellar masses $M_\star ^{\rm sat}\sim 10^{8\!-\!10.5}\, {\rm M}_\odot$, and live in hosts with $M_{\rm 200c}\sim 10^{12\!-\!14.3}\, {\rm M}_\odot$ at z = 0. We quantify the cold gas (T ≤ 104.5 K) removal using the tracer particles, confirming that for these jellyfish, RPS is the dominant driver of cold gas loss after infall. Half of these jellyfish are completely gas-less by z = 0, and these galaxies have earlier infall times and smaller satellite-to-host mass ratios than their gaseous counterparts. RPS can act on jellyfish galaxies over long time-scales of ≈1.5–8 Gyr. Jellyfish in more massive hosts are impacted by RPS for a shorter time span and, at a fixed host mass, jellyfish with less cold gas at infall and lower stellar masses at z = 0 have shorter RPS time spans. While RPS may act for long periods of time, the peak RPS period – where at least 50 per cent of the total RPS occurs – begins within ≈1 Gyr of infall and lasts ≲2 Gyr. During this period, the jellyfish are at host-centric distances ∼0.2–2R200c, illustrating that much of RPS occurs at large distances from the host galaxy. Interestingly, jellyfish continue forming stars until they have lost ≈98 per cent of their cold gas. For groups and clusters in TNG50 $(M_{\rm 200c}^{\rm host}\sim 10^{13\!-\!14.3}\, {\rm M}_\odot)$, jellyfish galaxies deposit more cold gas ($\sim 10^{11\!-\!12}\, {\rm M}_\odot$) into haloes than what exists in them at z = 0, demonstrating that jellyfish, and in general satellite galaxies, are a significant source of cold gas accretion.

Modeling the Chemical Enrichment History of the Bulge Fossil Fragment Terzan 5

Terzan 5 is a heavily obscured stellar system located in the inner Galaxy. It has been postulated to be a stellar relic, a bulge fossil fragment witnessing the complex history of the assembly of the Milky Way bulge. In this paper, we follow the chemical enrichment of a set of putative progenitors of Terzan 5 to assess whether the chemical properties of this cluster fit within a formation scenario in which it is the remnant of a primordial building block of the bulge. We can explain the metallicity distribution function and the runs of different element-to-iron abundance ratios as functions of [Fe/H] derived from optical-infrared spectroscopy of giant stars in Terzan 5 by assuming that the cluster experienced two major star formation bursts separated by a long quiescent phase. We further predict that the most metal-rich stars in Terzan 5 are moderately He-enhanced, and we predict a large spread of He abundances in the cluster, Y ≃ 0.26–0.335. We conclude that current observations fit within a formation scenario in which Terzan 5 originated from a pristine or slightly metal-enriched gas clump about one order of magnitude more massive than its present-day mass. Losses of gas and stars played a major role in shaping Terzan 5 the way we see it now. The iron content of the youngest stellar population is better explained if the white dwarfs that give rise to type Ia supernovae (the main Fe factories) sink toward the cluster center, rather than being stripped by the strong tidal forces exerted by the Milky Way in the outer regions.

The importance of biochar quality and pyrolysis yield for soil carbon sequestration in practice

AbstractBiochar is a carbon (C)‐rich material produced from biomass by anoxic or oxygen‐limited thermal treatment known as pyrolysis. Despite substantial gaseous losses of C during pyrolysis, incorporating biochar in soil has been suggested as an effective long‐term option to sequester CO2 for climate change mitigation, due to the intrinsic stability of biochar C. However, no universally applicable approach that combines biochar quality and pyrolysis yield into an overall metric of C sequestration efficiency has been suggested yet. To ensure safe environmental use of biochar in agricultural soils, the International Biochar Initiative and the European Biochar Certificate have developed guidelines on biochar quality. In both guidelines, the hydrogen‐to‐organic C (H/Corg) ratio is an important quality criterion widely used as a proxy of biochar stability, which has been recognized also in the new EU regulation 2021/2088. Here, we evaluate the biochar C sequestration efficiency from published data that comply with the biochar quality criteria in the above guidelines, which may regulate future large‐scale field application in practice. The sequestration efficiency is calculated from the fraction of biochar C remaining in soil after 100 years (Fperm) and the C‐yield of various feedstocks pyrolyzed at different temperatures. Both parameters are expressed as a function of H/Corg. Combining these two metrics is relevant for assessing the mitigation potential of the biochar economy. We find that the C sequestration efficiency for stable biochar is in the range of 25%–50% of feedstock C. It depends on the type of feedstock and is in general a non‐linear function of H/Corg. We suggest that for plant‐based feedstock, biochar production that achieves H/Corg of 0.38–0.44, corresponding to pyrolysis temperatures of 500–550°C, is the most efficient in terms of soil carbon sequestration. Such biochars reveal an average sequestration efficiency of 41.4% (±4.5%) over 100 years.

Study on gas desorption law and gas loss estimation in a positive pressure reverse circulation sampling process

The accurate estimation of gas loss is a difficult problem in direct methods for measuring coalbed gas content. When using positive pressure reverse circulation (PPRC) technology to determine gas content, estimating the gas loss of coal samples under positive pressure based on the desorption law under atmospheric pressure may lead to significant errors. To study the gas desorption law in granular coal during PPRC sampling, positive pressure (PP) and positive pressure to atmospheric pressure (PP-AP) gas desorption experiments were conducted, and the gas diffusion kinetic parameters were analysed. The results showed that when the desorption pressure changed from PP to AP, the gas desorption capacity suddenly increased. Under a PP condition, the initial gas desorption rate decreased with increasing desorption PP, which could be expressed by a power function. While the AP initial gas desorption rate increased. Compared to the AP condition, the larger mass transfer resistance Bi and the smaller mass transfer Fourier number F0 in the PP experiments indicated that PP limited the migration of gas in coal particles, resulting in a smaller gas diffusion coefficient. The t model, power model, and logarithmic model were used to analyse the gas desorption data, confirming that existing methods for estimating gas loss have significant errors, and the power model can better describe the PP desorption process. Finally, a device was proposed to avoid pressure changes during sampling and underground desorption analysis. It was verified that using this device, the estimation error in gas loss could be reduced to within 10%. These results can provide guidance for further improving PPRC sampling technology.

Surface geochemical anomaly pattern of medium-to-high temperature geothermal systems in South China and its application

The existence of thermal storage will correspondingly increase the temperature of surrounding strata and promote the continuous expansion, volatilization, upward migration, and loss of gas in the strata. As a result, a low-concentration gas field will be formed in the strata above geothermal reservoirs. Geothermal reservoirs could in turn heat formation water and increase the solubility of soluble inorganic salts in the surrounding rocks and the total dissolved solids (TDS) content in the formation water. Since water can strongly wet and permeate strata, the dissolved inorganic salts migrate into upper strata along with water, giving rise to the formation of a high-concentration inorganic salt field in the strata above geothermal reservoirs. A higher geothermal reservoir temperature corresponds to more significant characteristics mentioned above. Therefore, a medium-to-high temperature geothermal system has a surface geochemical anomaly pattern of high inorganic salt concentrations and low gas concentrations (also referred to as the high-salt and low-gas pattern). This pattern is applied to the surface geochemical exploration of the two geothermal fields in Guangdong Province, i.e., the Huangshadong geothermal field in Huizhou City and the Xinzhou geothermal field in Yangjiang City, revealing low-concentration gas fields above both. The application results also show that the exposed thermal spring water in both geological fields has higher concentration of dissolved inorganic salt than the surface water and nearby seawater, forming high-amplitude anomalies on the surface above geothermal reservoirs. These characteristics, as well as the measured temperature at known geothermal wells, verify the validity of the high-salt and low-gas pattern of medium-to-high temperature geothermal systems proposed in this study. Moreover, the high-salt and low-gas pattern proposed predicts three favorable medium-to-high temperature geothermal zones in the surface geochemical exploration of the Shiba Basin near the Huangshadong geothermal field.

Understanding the process-microstructure-property relationships in material extrusion additive manufacturing of polylactic acid microcellular foams

Process-microstructure-property relationships are reported for microcellular foams printed via material extrusion (MEX) additive manufacturing (AM) process. Polylactic acid and thermally expandable microspheres were mixed and extruded to prepare the filament. In situ foaming during MEX AM process was then conducted to investigate the impact of nozzle temperature, flow rate, and print speed on the cellular morphology, mesostructure, part density, and the mechanical behavior of the foams. The temperature and the residence time were identified as the two key factors governing the foaming behavior and thus the resultant microstructure and properties. Too excessive temperature and residence time resulted in the deformed, wrinkled, or collapsed microspheres due to gas loss and contraction. On the other hand, too low temperature and residence time caused limited number of microspheres to expand, due to insufficient energy and time. Both overly activated and partially unexpanded microspheres provided nonuniform cellular morphologies and higher densities and thus adversely affected the tensile properties. The foam expansion/shrinkage behavior during the MEX AM process was demonstrated as a function of a combined process variable that unifies temperature, flow rate, and print speed. Upon the utilization of the optimum process variables, foam samples with uniform morphology, low density, and high toughness were achieved. The results shed light on the understanding and advancing of MEX AM process as a novel manufacturing approach to produce quality foams.

Carbon isotope evidence for shale gas preservation conditions and large methane release over million years: A case study of shale gas reservoirs of Wufeng and Longmaxi Formations in the Sichuan Basin

Although carbon isotope reversal and its reasons in shale gas reservoirs have been widely recognized, the application of the reversal is yet to be investigated. A study on high-maturity shale from Wufeng and Longmaxi Formations in the Sichuan Basin not only reveals the relationship between the degree of isotopes inversion and the production capacity (e.g., estimated ultimate recovery (EUR)) of the gas well but also indicates the preservation conditions of shale gas reservoirs. (1) Although there are differences in gas isotopes in different shale gas reservoirs, the isotope fractionation of shale gas is small during the production stage of gas wells, even when the wellbore pressure drops to zero. The main cause of the difference in carbon isotopes and their inversion degree can be the uplift time during the Yanshan period and the formation pressure relief degree of shale gas reservoirs in distinct structural positions. Thus, carbon isotope inversion is a good indicator of shale gas preservation condition and EUR of shale gas wells. (2) The degree of carbon isotope inversion correlates strongly with shale gas content and EUR. The calculation formula of shale-gas recoverable reserves was established using Δδ13C (δC1-δC2) and EUR. (3) The gas loss rate and total loss amount can be estimated using the dynamic reserves and isotopic difference values of gas wells in various shale gas fields, which also reflects the current methane loss, thereby demonstrating great potential for evaluating global methane loss in shales.

Yield and nutritional value of silage of different sorghum hybrids inoculated with Azospirillum brasilense

ABSTRACT The objective of this study was to evaluate sorghum hybrids associated or not associated with Azospirillum brasilense and nitrogen fertilization (N) during planting on the yield, fermentative profile, and nutritional value of the respective silages. Five sorghum hybrids (Volumax, 201813B, 201814B, 201709B, BRS716) were evaluated with three nitrogen fertilization strategies using urea (100 kg ha−1 of N) and Azospirillum brasilense, and urea (100 kg ha−1 of N)/A. brasilense in association. A randomized block design was used in a 5 × 3 factorial scheme, with five hybrids, three fertilization strategies and three replications (blocks). The useful area of each experimental unit was 3 m x 3 m. The biomass sorghum hybrids showed a dry matter (DM) production (P = 0.01) 48.31% higher than the DM production of the Volumax forage (mean of 17.49 t ha−1 of dry matter). There was no difference between the sorghum hybrid silages in the pH values (mean of 4.11; P = 0.68), gas losses (mean of 3.74% of DM; P = 0.19). The sorghum hybrids biomass 201709B and BRS 716 showed better digestible and DM productivity. Azospirillum brasilense can be used as a nitrogen fertilization strategy in partial or total replacement of urea.

The impact of different fertiliser management options and cultivars on nitrogen use efficiency and yield for rice cropping in the Indo-Gangetic Plain: Two seasons of methane, nitrous oxide and ammonia emissions

This study presents detailed crop and gas flux data from two years of rice production at the experimental farm of the ICAR-Indian Agricultural Research Institute, New Delhi, India. In comparing 4 nitrogen (N) fertiliser regimes across 4 rice cultivars (CRD 310, IR-64, MTU 1010, P-44), we have added to growing evidence of the environmental costs of rice production in the region. The study shows that rice cultivar can impact yields of both grain, and total biomass produced in given circumstances, with the CRD 310 cultivar showing consistently high nitrogen use efficiency (NUE) for total biomass compared with other tested varieties, but not necessarily with the highest grain yield, which was P-44 in this experiment. While NUE of the rice did vary depending on experimental treatments (ranging from 41% to 73%), 73%), this did not translate directly into the reduction of emissions of ammonia (NH3) and nitrous oxide (N2O). Emissions were relatively similar across the different rice cultivars regardless of NUE. Conversely, agronomic practices that reduced total N losses were associated with higher yield. In terms of fertiliser application, the outstanding impact was of the very high methane (CH4) emissions as a result of incorporating farmyard manure (FYM) into rice paddies, which dominated the overall effect on global warming potential. While the use of nitrification and urease inhibiting substances decreased N2O emissions overall, NH3 emissions were relatively unaffected (or slightly higher). Overall, the greatest reduction in greenhouse gas (GHG) emissions came from reducing irrigation water added to the fields, resulting in higher N2O, but significantly less CH4 emissions, reducing net GHG emission compared with continuous flooding. Overall, genetic differences generated more variation in yield and NUE than agronomic management (excluding controls), whereas agronomy generated larger differences than genetics concerning gaseous losses. This study suggests that a mixed approach needs to be applied when attempting to reduce pollution and global warming potential from rice production and potential pollution swapping and synergies need to be considered. Finding the right balance of rice cultivar, irrigation technique and fertiliser type could significantly reduce emissions, while getting it wrong can result in considerably poorer yields and higher pollution.

Strategies To Improve the Performance of Hydrogen Storage Systems by Liquefaction Methods: A Comprehensive Review.

The main challenges of liquid hydrogen (H2) storage as one of the most promising techniques for large-scale transport and long-term storage include its high specific energy consumption (SEC), low exergy efficiency, high total expenses, and boil-off gas losses. This article reviews different approaches to improving H2 liquefaction methods, including the implementation of absorption cooling cycles (ACCs), ejector cooling units, liquid nitrogen/liquid natural gas (LNG)/liquid air cold energy recovery, cascade liquefaction processes, mixed refrigerant systems, integration with other structures, optimization algorithms, combined with renewable energy sources, and the pinch strategy. This review discusses the economic, safety, and environmental aspects of various improvement techniques for H2 liquefaction systems in more detail. Standards and codes for H2 liquefaction technologies are presented, and the current status and future potentials of H2 liquefaction processes are investigated. The cost-efficient H2 liquefaction systems are those with higher production rates (>100 tonne/day), higher efficiency (>40%), lower SEC (<6 kWh/kgLH2), and lower investment costs (1-2 $/kgLH2). Increasing the stages in the conversion of ortho- to para-H2 lowers the SEC and increases the investment costs. Moreover, using low-temperature waste heat from various industries and renewable energy in the ACC for precooling is significantly more efficient than electricity generation in power generation cycles to be utilized in H2 liquefaction cycles. In addition, the substitution of LNG cold recovery for the precooling cycle is associated with the lower SEC and cost compared to its combination with the precooling cycle.