On the Chemical Pathways Influencing the Effective Global Warming Potential of Commercial Hydrofluoroolefin Gases.

The enforcement of a global hydrofluorocarbon (HFC) refrigerant phase down led to the introduction of hydrofluoroolefins (HFOs) as a low Global Warming Potential (GWP) substitute, given their low atmospheric lifetime. However, to this date it is not fully clear the long-term atmospheric fate of HFOs primary degradation products: trifluoro acetaldehyde (TFE), trifluoro acetyl fluoride (TFF), and trifluoroacetic acid (TFA). It particularly concerns the possibility of forming HFC-23, a potent global warming agent. Although the atmospheric reaction networks of TFE, TFF, and TFA have a fair level of complexity, the relevant atmospheric chemical pathways are well characterized in the literature, enabling a comprehensive hazard assessment of HFC-23 formation as a secondary HFO breakdown product in diverse scenarios. A lower bound of the HFOs effective GWP in a baseline scenario is found above regulatory thresholds. While further research is crucial to refine climate risk assessments, the existing evidence suggests a non-negligible climate hazard associated with HFOs.

On the Feasibility of Rugose Lipid Microparticles in Pressurized Metered Dose Inhalers with Established and New Propellants.

Pressurized metered dose inhalers (pMDIs) require optimized formulations to provide stable, consistent lung delivery. This study investigates the feasibility of novel rugose lipid particles (RLPs) as potential drug carriers in pMDI formulations. The physical stability of RLPs was assessed in three different propellants: the established HFA-134a and HFA-227ea and the new low global-warming-potential (GWP) propellant HFO-1234ze. A feedstock containing DSPC and calcium chloride was prepared without pore forming agent to spray dry two RLP batches at inlet temperatures of 55 °C (RLP55) and 75 °C (RLP75). RLPs performance in pMDI formulations was compared to two reference samples that exhibit significantly different performance when suspended in propellants: well-established engineered porous particles and particles containing 80% trehalose and 20% leucine (80T20L). An accelerated stability study at 40 °C and relative humidity of 7% ± 5% was conducted over 3 months. At different time points, a shadowgraphic imaging technique was used to evaluate the colloidal stability of particles in pMDIs. Field emission electron microscopy with energy dispersive X-ray spectroscopy was used to evaluate the morphology and elemental composition of particles extracted from the pMDIs. After 2 weeks, all 80T20L formulations rapidly aggregated upon agitation and exhibited significantly inferior colloidal stability compared to the other samples. In comparison, both the RLP55 and RLP75 formulations, regardless of the propellant used, retained their rugose structure and demonstrated excellent suspension stability comparable with the engineered porous particles. The studied RLPs demonstrate great potential for use in pMDI formulations with HFA propellants and the next-generation low-GWP propellant HFO-1234ze.

Air Humidity Influence on Combustion of R-1234yf (CF3CFCH2), R-1234ze(E) (trans-CF3CHCHF) and R-134a (CH2FCF3) Refrigerants.

The influence of air humidity on flame propagation in mixtures of hydrofluorocarbons (HFCs) with air was studied through numerical simulations and comparison with measurements from the literature. Water vapor added to the air in mixtures of fluorine rich hydrofluorocarbons (F/H≥1) can be considered as a fuel additive that increases the production of radicals (H, O, OH) and increases the overall reaction rate. The hydrofluorocarbon flame is typically a two-stage reaction proceeding with a relatively fast reaction in the first stage transitioning to a very slow reaction in the second stage which leads to the combustion equilibrium products. The transition to the second stage is determined by the consumption of hydrogen-containing species and formation of HF. Despite a relatively small effect of water on the adiabatic combustion temperature, its influence is significant on the reaction rate and on the temperature increase in the first stage of the combustion leading to the increase in burning velocity. The main reaction for converting H2O to hydrogen-containing radicals and promoting combustion is H2O+F=HF+OH, as demonstrated by reaction path analyses for the fluorine rich hydrofluorocarbons R-1234yf, R-1234ze(E), and R-134a (F/H = 2). The calculated burning velocity dependence on the equivalence ratio ϕ agrees reasonably well with available experimental measurements for R1234yf and R-1234ze(E) with and without the addition of water vapor. In agreement with experimental data, with water vapor, the maximum of burning velocity over ϕ is shifted to the lean mixtures (near ϕ = 0.8).

[Dual-Perspective Analysis of the Warming Effect of the Methane Emissions from Animal Husbandry in China].

Accurate quantitative evaluation of the greenhouse effects of methane(CH4) is the foundation for developing effective mitigation strategies. This study was the first to quantitatively evaluate the warming effects of the CH4 emissions from animal husbandry in China using the recently proposed climate metric GWP-star(GWP*), which is designed for short-lived climate pollutants(SLCP), and to compare the results with the commonly used climate metric global warming potential(GWP). The results showed:CH4emissions from animal husbandry in China decreased from 957.0×105 t in 2000 to 764.0×105 t. The GWP results showed that the greenhouse effect of CH4 emissions from animal husbandry in China was increasing between 2015 and 2019, and the GWP* results showed that it decreased compared to that 20 years ago. The amount of reduction was equivalent to removing the warming of 2.1×108 t of carbon dioxide. Under the GWP evaluation system, achieving carbon neutrality in the livestock industry in China requires eliminating or offsetting stable annual CH4 emissions from increased carbon sinks. Instead, under the GWP* evaluation system, China's livestock industry could achieve its carbon neutrality in the short term by effectively reducing CH4 emissions by only 0.3% per year. In the case that the livestock industry in China continues to take effective emission reduction measures, the reduction target under the GWP* metric will be reached earlier than that under GWP. Still, the choice of GWP or GWP* requires careful consideration of the objectives of evaluation, the time scale of assessment, and practical operability.

Integrated Performance Evaluation of Aerogel-Based Fibre-Enhanced Thermal Renders Applied on Building Walls.

In this work, aerogel renders were enhanced with fibres for use in new building walls, emphasising a Mediterranean climate. The main novelty of the study relies on an integrated evaluation of the aerogel-based fibre-enhanced thermal renders from environmental, energy and economic approaches. Therefore, optimum insulation thicknesses, life cycle savings, payback periods, abiotic depletion potential from fossil fuels (ADP-ff) and global warming potential (GWP) impacts were quantified as a function of the energy consumption. The cost optimisation of aerogel-based renders enabled a reduction from 2477.4 to 1021.7 EUR∙m-3 for the reference formulation, and the sisal-optimised render led to the best-integrated performance. A higher DD* (degree-days equivalent) led to higher optimum thicknesses (the Azores required 0.02 m and 0.01 m and Bragança 0.06 m and 0.03 m for cost-optimised and non-optimised thermal renders with sisal fibre, respectively). The optimum thickness related to the ADP-ff and GWP impacts was higher, 0.04 m for the Azores and 0.09 m for Bragança. A steeper decrease in the annual energy consumption occurred for thermal renders up to 0.02 m in the Azores and 0.04 m in Bragança. Aerogel-based fibre-enhanced thermal renders had benefits, mainly from 600 DD* onwards.

Evaluating Sustainable Development Pathways for Protein- and Peptide-Based Bioadsorbents for Phosphorus Recovery from Wastewater.

Recovering phosphate (P) from point sources such as wastewater effluent is a priority in order to alleviate the impacts of eutrophication and implement a circular economy for an increasingly limited resource. Bioadsorbents featuring P-binding proteins and peptides offer exquisite P specificity and sensitivity for achieving ultralow P concentrations, i.e., <100 µg P L-1, a discharge limit that has been implemented in at least one treatment facility in nine U.S. states. To prioritize research objectives for P recovery in wastewater treatment, we compared the financial and environmental sustainability of protein/peptide bioadsorbents to those of LayneRT anion exchange resin. The baseline scenario (reflecting lab-demonstrated performance at a full-scale implementation) had costs that were 3 orders of magnitude higher than those for typical wastewater treatment. However, scenarios exploring bioadsorbent improvements, including increasing the P-binding capacity per unit volume by using smaller P-selective peptides and nanoparticle base materials and implementing reuse, dramatically decreased median impacts to $1.06 m-3 and 0.001 kg CO2 equiv m-3; these values are in line with current wastewater treatment impacts and lower than the median LayneRT impacts of $4.04 m-3 and 0.19 kg CO2 equiv m-3. While the financial viability of capturing low P concentrations is a challenge, incorporating the externalities of environmental impacts may provide a feasible path forward to motivate ultralow P capture.

PvT Properties and Thermodynamic Property Correlations for the Low Global Warming Potential Hydrofluoroolefin Refrigerant R-1132a (1,1-Difluoroethene).

R-1132a is increasingly being considered as a low global warming potential component in alternative mixtures to R-23 in specialized low temperature and ultra-low temperature refrigeration systems. Though the thermodynamic properties of R-1132a were investigated in several studies up to 2018, reinvestigations have been carried out in recent years. In order to contribute toward these renewed measurements, the critical parameters of R-1132a were experimentally re-determined. Thirty-two vapor pressures from 240 K to the critical temperature, fifteen saturated vapor and six saturated liquid densities above 254 K and the PvT properties in both the vapor phase (98 points) and liquid phase (34 points) from densities of 50 kg·m-3 to 760 kg·m-3 were also measured. Specific correlations for each of these properties were optimized and compared to previously available data from the literature. Additionally, the Peng-Robinson equation of state was used to represent the aforementioned properties and further utilized to determine the enthalpy and entropy of R-1132a. Supplementary Information: The online version contains supplementary material available at 10.1007/s10765-023-03184-4.

Subsurface fertilization boosts crop yields and lowers greenhouse gas emissions: A global meta-analysis.

The subsurface application (SA) of nitrogenous fertilizers is a potential solution to mitigate climate change and improve food security. However, the impacts of SA technology on greenhouse gas (GHG) emissions and agronomic yield are usually evaluated separately and their results are inconsistent. To address this gap, we conducted a meta-analysis synthesizing 40 peer-reviewed studies on the effects of SA technology on GHG and ammonia (NH3) emissions, nitrogen uptake (NU), crop yield, and soil residual NO3-N in rice paddies and upland cropping system. Compared to the surface application of N, SA technology significantly increased rice yields by 32 % and crop yield in upland systems by 62 %. The largest SA-induced increases in crop yield were found at low N input rates (<100 kg Nha-1) in rice paddies and medium N input rates (100-200 kg Nha-1) in upland systems, suggesting that soil moisture is a key factor determining the efficiency of SA technology. SA treatments increased yields by more at reduced fertilizer rates (~30 % less N), a shallow depth (<10 cm), and with urea in both cropping systems than at the full (recommended) N rate, a deeper depth (10-20 cm), and with ammonical fertilizer. SA treatments significantly increased NU in rice paddies (34 %) and upland systems (18 %), and NO3-N (40 %) in paddyland; however, NO3-N decreased (28 %) in upland conditions. Ammonia mitigation was greater in paddyland than in upland conditions. SA technology decreased the carbon footprint (CF) in paddyland by 29 % and upland systems by 36 %, and overall by 33 %. Compared with broadcasting, SA significantly reduced CH4 emissions by 16 %, N2O emissions by 30 %, and global warming potential (GWP) by 10 % in paddy cultivation. Given SA increased grain yield and NU while reducing NH3, CF, and GWP, this practice provides dual benefits - mitigating climate change and ensuring food security.

Sustainable strategies related to soil fertility, economic benefit, and environmental impact on pear orchards at the farmer scale in the Yangtze River Basin, China.

Pears are an important income source in China, and unreasonable management practices have had a negative impact on the sustainability of pear orchards. However, multi-objective synergistic strategies are unclear on a farmer scale. In this study, we quantified indicators of soil fertility (soil organic matter (SOM)), environmental impact (global warming potentials (GWP)), and economic benefit (ratio of benefit and cost (BCR)) and analysed the synergetic strategies based on survey data from 230 smallholders in the Yangtze River Basin (Shanghai City, Chongqing City, Zhejiang province, and Jiangxi province). The average SOM, GWP, and BCR were 28.9 g kg-1, 17.3 t CO2-eq ha-1, and 3.63, respectively. Furthermore, optimised solutions using the Pareto multiple-objective optimisation model can reduce the GWP by 44.6% and improve the SOM and BCR by 34.4% and 43.9%, respectively, when fertiliser N rate and density are both decreased and the ratio of organic fertiliser application is increased compared to farmer management practices. The structural equation model indicated that planting density and fertiliser N rate can directly influence GWP and indirectly increase SOM and BCR; organic fertiliser application directly affects the GWP, SOM, and BCR. Our research provides a bottom-up approach based on the farmer scale, which can improve the sustainability of pear systems, and these findings can be used as guidelines for policymakers and pear orchard managers.

Application of an integrated loach-plant-substrate-microbes non-aerated saturated vertical flow constructed wetlands: Mechanisms of pollutants removal and greenhouse gases reduction.

This study established an integrated loach-plant-substrate-microbes non-aerated saturated vertical flow constructed wetlands (VFCWs) to enhance pollutants removal efficiencies and reduce greenhouse gas emissions simultaneously. The results of the VFCWs experiment indicated that the removal efficiencies of chemical oxygen demand, total phosphorous, and total nitrogen in loach systems were significantly higher than those of non-loach systems, achieving 59.16%, 35.98%, and 40.96%, respectively. The CH4 and N2O emission fluxes were also significantly reduced in the integrated system, resulting in lower global warming potential (GWP) and GWP per unit of pollutants removal. Loaches promoted the transportation of oxygen, facilitated the re-contact and utilization of sediments, reduced CH4 emission, and enhanced nitrogen conversion and phosphorus accumulation. Increased bioavailable carbon and nitrate-nitrogen in the integrated system improved the abundance of denitrifying bacteria, which supported complete denitrification, reducing N2O emissions with high pollutant removal.

Implementing an appropriate metric for the assessment of greenhouse gas emissions from livestock production: A national case study.

Livestock farming is of major economic relevance but also severely contributes to environmental impacts, especially greenhouse gas (GHG) emissions such as methane (CH4; particularly from ruminant production) and nitrous oxide (N2O; mainly from manure management and soil cultivated for feed production). In this study, we analyse the impact of GHG emissions from Austrian livestock production, using two metrics: a) the commonly used global warming potential (GWP) over 100 years (GWP100 in CO2-equivalents, CO2-e), and b) the recently introduced metric GWP*, which describes additional warming as a function of the timeline of short-lived GHG emissions (unit CO2 warming equivalents, CO2-we). We first compiled the sectoral (i.e. only direct emissions without upstream processes) GWP100 for different livestock categories with a focus on dairy cattle, beef cattle and pigs in Austria between 1990 and 2019. We also estimated product-related (i.e. per kg carcass weight or per litre of milk) GWP100 values, including upstream processes. We then calculated the corresponding GWP* metrics, both sectoral and product-related, and compared them with the GWP100 values. Decreasing livestock numbers and improved production efficiency were found to result in strong sectoral emission reductions from dairy production (-32 % of GWP100 from 1990 to 2019) and from pigs (-32 % CO2-e). This contrasts with low reductions from other livestock categories and even increases for cattle other than dairy cows (+3 % CO2-e), mainly due to rising suckler cow numbers. Allocated results per kg milk and kg body mass show quite similar results. Using the GWP* metric, the climate impacts of Austrian livestock production are less severe. When assuming constant management and emission intensity over a period of at least 20 years, the CO2-we (GWP*) is almost 50 % less than CO2-e (GWP100) per kg Austrian raw milk due to the different impacts of the short-lived CH4. A similar trend applies to an average cattle carcass (-40 % warming impact). The emission reductions of the shrinking Austrian livestock population represent an important contribution to a climate-neutral agriculture: The CH4 reductions of livestock production during the past 20 years reduce the current total Austrian CO2-we by 16 %. Continuous CH4 reduction, as we show it here for Austrian livestock, is an effective option to tackle the climate crisis in the short term. It shall be stressed that a relatively low GWP* should not be interpreted as a concession for further CH4 emissions but as an actual reduction of (additional) warming.

[Effect of Winter Cover Cropping on Soil Greenhouse Gas Emissions in a Dryland Spring Maize Field on the Loess Plateau of China].

A field experiment was carried out to study the effects of winter cover cropping on soil greenhouse gas emissions in dryland maize. Four cover crop treatments, namely oat, lentil, a mixture of oat and lentil, and no cover crops (CK), were included during the winter fallow period. Greenhouse gas emission fluxes from soil were measured using the static chamber-gas chromatograph technique. The results showed that:both soil CO2 and N2O were emitted, but the soil acted as a sink for CH4. Compared with the that in CK, oat and lentil had no effect on the cumulative amount of soil CO2 emissions during the winter fallow period and increased the cumulative amount of soil CO2 emissions by 7.77% and 25.7% (P<0.05) in the spring maize growing period, respectively; the mixture increased the cumulative amount of soil CO2 emissions by 19.1% and 14.5% (P<0.05) during the winter fallow and spring maize growing periods. In the winter fallow and spring maize periods, compared with that in CK, oat declined the cumulative amount of soil N2O emissions by 11.6% and 14.7% (P<0.05), and lentil increased the cumulative amount of soil N2O emissions by 31.9% and 14.9% (P<0.05), respectively. Compared to that in the CK, the mixture declined the cumulative amount of soil N2O emissions by 19.2% (P<0.05) in the winter fallow period but had no effect in the spring maize period. Compared with the CK, oat, lentil, and their mixture resulted in a declined cumulative amount of soil CH4 uptake by 37.9%, 23.6%, and 29.6% (P<0.05) in the winter fallow period and by 19.4%, 33.5%, and 31.5% (P<0.05) in the spring maize growing period, respectively. Compared with the CK, oat had no effect on global warming potential (GWP), maize yield, and greenhouse gas intensity (GHGI). Lentil and the mixture increased GWP, and lentil showed a greater increase in GWP than that of the mixture. Compared with the CK, lentil and the mixture increased maize yield by 20.3% and 15.4% (P<0.05), respectively, and had no effect on GHGI. The findings from this study show that the lentil and oat mixture can significantly increase maize yield and decrease GHGI.

[Life Cycle Assessment and Key Parameter Comparison of Hydrogen Fuel Cell Vehicles Power Systems].

Hydrogen fuel cell vehicles (HFCVs) are regarded as potential solutions to the problems of energy security and environmental pollution. To explore the energy consumption and pollutant emissions of fuel cell vehicle power systems, data inventories of an HFCV power system were established, and quantitative evaluation calculations and prediction analysis were carried out for fuel life cycle energy consumption and greenhouse gas emissions of Chinese fuel cell vehicles in 2030 based on the technology roadmap for new energy vehicles by modeling with GaBi software. The effects of different types of bipolar plates, different energy control strategies, and different hydrogen production methods on the environment were studied, with uncertainty analysis as the key parameter. The results showed that fossil energy consumption (ADPf), global warming potential (GWP, CO2 equivalent), and acidification potential (AP, SO2 equivalent) for the HFCV power system in the fuel life cycle were 1.35×105 MJ, 9108 kg, and 15.79 kg, respectively. The energy consumption and greenhouse gas emissions in the production of the power system were higher than those in the use stage, mainly because of the fuel cell stack and hydrogen storage tank. In the manufacturing process of metal bipolar plates, graphite composite bipolar plates, and graphite bipolar plates, graphite composite bipolar plates had the most comprehensive environmental benefits. Optimizing the energy control strategy will reduce hydrogen energy consumption. When the hydrogen energy consumption was reduced by 22.8%, the life cycle energy consumption and greenhouse gas emissions of the power system were reduced by 10.4% and 8.3%, respectively. For life cycle power systems, the use of hydrogen from electrolysis operated with water power reduced the GWP by approximately 39.6% relative to steam methane reforming. In contrast, the application of hydrogen from electrolysis operated with the Chinese electricity grid mix resulted in an increase in GWP of almost 53.7%. Measures to reduce fossil energy consumption and global warming potential in the life cycle of fuel cell vehicle powertrains include optimizing energy control strategies to reduce hydrogen energy consumption, scaling up the hydrogen production industry using water electrolysis for renewable energy power generation, and focusing on key technologies of fuel cell stacks to improve performance.

The key role of propane in a sustainable cooling sector.

Split air conditioners (ACs) are the most used appliance for space cooling worldwide. The phase-down of refrigerants with high global warming potential (GWP) prescribed by the Kigali Amendment to the Montreal Protocol has triggered a major effort to find less harmful alternative refrigerants. HFC-32 is currently the most common refrigerant to replace HFC-410A in split ACs. The GWP of HFC-32 is about one-third that of HFC-410A but still considerably higher than that of a growing number of nonfluorinated alternatives like propane with a GWP of <1, which have recently become commercially available for split ACs. Here, we show that a switch to propane as an energy-efficient and commercially available low-GWP alternative in split ACs could avoid 0.09 (0.06 to 0.12) °C increase in global temperature by the end of the century. This is significantly more than the 0.03 (0.02 to 0.05) °C avoided warming from a complete switch to HFC-32 in split ACs.

Transitioning to low-GWP alternatives with enhanced energy efficiency in cooling non-residential buildings of China.

The electricity demand for space cooling in the non-residential building (NRB) sector of China is growing significantly and is becoming increasingly critical with rapid economic development and mounting impacts of climate change. The growing demand for space cooling will increase global warming due to emissions of hydrofluorocarbons used in cooling equipment and carbon dioxide emissions from the mostly fossil fuel-based electricity currently powering space cooling. This study uses the Greenhouse Gas and Air Pollution Interaction and Synergies (GAINS) model framework to estimate current and future emissions of hydrofluorocarbons and their abatement potentials for space cooling in the NRB sector of China and assess the co-benefits in the form of savings in electricity and associated reductions in greenhouse gas (GHG), air pollution, and short-lived climate pollutant emissions. Co-benefits of space cooling are assessed by taking into account (a) regional and urban/rural heterogeneities and climatic zones among different provinces; (b) technical/economic energy efficiency improvements of the cooling technologies; and (c) transition towards lower global warming potential (GWP) refrigerants under the Kigali Amendment. Under the business-as-usual (BAU) scenario, the total energy consumption for space cooling in the NRB sector will increase from 166 TWh in 2015 to 564 TWh in 2050, primarily due to the rapid increase in the floor space area of non-residential buildings. The total GHG mitigation potential due to the transition towards low-GWP refrigerants and technical energy efficiency improvement of cooling technologies will approximately be equal to 10% of the total carbon emissions from the building sector of China in 2050. Supplementary Information: The online version contains supplementary material available at 10.1007/s11027-022-10021-w.

Effects of no-tillage on greenhouse gas emissions in maize fields in a semi-humid temperate climate region.

Agricultural tillage practices have a significant impact on the generation and consumption of greenhouse gases (GHGs), the primary causes of global warming. Two tillage systems, conventional tillage (CT) and no-tillage (NT), were compared to evaluate their effects on GHG emissions in this study. Averaged from 2018 to 2020, significant decreases of CO2 and N2O emissions by 7.4% and 51.1% were observed in NT as compared to those of CT. NT was also found to inhibit the soil CH4 uptake. In this study, soil was a source of CO2 and N2O but a sink for CH4. The effect of soil temperature on the fluxes of CO2 was more pronounced than that of soil moisture. However, soil temperature and soil moisture had a weak correlation with CH4 and N2O flux variations. As compared to CT, NT did not affect maize yields but significantly reduced global warming potential (GWP) by 8.07%. For yield-scaled GWP, no significant difference was observed in NT (9.63) and CT (10.71). Taken together, NT was an environment-friendly tillage practice to mitigate GHG emissions in the soil under the tested conditions.

Being applied at rice or wheat season impacts biochar's effect on gaseous nitrogen pollutants from the wheat growth cycle.

Biochar (BC) application to agricultural soil can impact two nitrogen (N) gases pollutants, i.e., the ammonia (NH3) and nitrous oxide (N2O) losses to atmospheric environment. Under rice-wheat rotation, applied at which growth cycle may influence the aforementioned effects of BC. We conducted a soil column (35 cm in inner diameter and 70 cm in height) experiment to evaluate the responses of wheat N use efficiency (NUE), NH3 volatilization, and N2O emission from wheat season to biochar applied at rice (R) or wheat (W) growth cycle, meanwhile regarding the effect of inorganic fertilizer N input rate, i.e., 72, 90, and 108 kg ha-1 (named N72, N90, and N108, respectively). The results showed that BC application influenced the wheat growth and grain yield. In particular, BC applied at rice season increased the wheat grain yield when receiving 90 and 108 kg N ha-1. The improved wheat grain yield was attributed to that N90 + BC(R) and N108 + BC(R) enhanced the wheat NUE by 53.8% and 52.8% over N90 and N108, respectively. More N input led to higher NH3 volatilization and its emission factor. Interestingly, 19.7%-34.0% lower NH3 vitalizations were recorded under treatments with BC applied in rice season, compared with the treatments only with fertilizer N. BC applied at rice season exerted higher efficiency on mitigating N2O emission than that applied at wheat season under three N input rates, i.e., 60.5%-77.6% vs 29.8%-34.8%. Overall, considering the crop yield and global warming potential resulting from NH3 volatilization and N2O emission of wheat season, N90 + BC(R) is recommended. In conclusion, farmers should consider the application time and reduce inorganic fertilizer N rate when using BC.

Genome-Enabled Prediction Methods Based on Machine Learning.

Growth of artificial intelligence and machine learning (ML) methodology has been explosive in recent years. In this class of procedures, computers get knowledge from sets of experiences and provide forecasts or classification. In genome-wide based prediction (GWP), many ML studies have been carried out. This chapter provides a description of main semiparametric and nonparametric algorithms used in GWP in animals and plants. Thirty-four ML comparative studies conducted in the last decade were used to develop a meta-analysis through a Thurstonian model, to evaluate algorithms with the best predictive qualities. It was found that some kernel, Bayesian, and ensemble methods displayed greater robustness and predictive ability. However, the type of study and data distribution must be considered in order to choose the most appropriate model for a given problem.

Gas-Phase Chemistry of 1,1,2,3,3,4,4-Heptafluorobut-1-ene Initiated by Chlorine Atoms.

The possibility of mitigating climate change by switching to materials with low global warming potentials motivates a study of the spectroscopic and kinetic properties of a fluorinated olefin. The relative rate method was used to determine the rate constant for the reaction of heptafluorobut-1-ene (CF2=CFCF2CF2H) with chlorine atoms in air. A mercury UV lamp was used to generate atomic chlorine, which initiated chemistry monitored by FTIR spectroscopy. Ethane was used as the reference compound for kinetic studies. Oxidation of heptafluorobut-1-ene initiated by a chlorine atom creates carbonyl difluoride (CF2=O) and 2,2,3,3 tetrafluoropropanoyl fluoride (O=CFCF2CF2H) as the major products. Anharmonic frequency calculations allowing for several low-energy conformations of 1,1,2,3,3,4,4 heptafluorobut-1-ene and 2,2,3,3 tetrafluoropropanoyl fluoride, based on density functional theory, are in good accord with measurements. The global warming potentials of these two molecules were calculated from the measured IR spectra and estimated atmospheric lifetimes and found to be small, less than 1.

Life cycle flaring emissions mitigation potential of a novel Fischer-Tropsch gas-to-liquid microreactor technology for synthetic crude oil production.

This paper compares the environmental impacts of the operation of a novel Gas-to-Liquid (GtL) process for synthetic crude oil production with conventional crude oil production. This process uses novel microreactor technology (NetMIX) applied in Steam Methane Reforming and Fischer-Tropsch (FT-SMR) for the conversion of associated gas originated on offshore Oil and Gas exploration. Data from literature for Oil and Gas extraction together with data obtained from Aspen Plus ® simulations was used to build the life cycle inventory. An attributional Life Cycle Assessment (LCA) was performed to compare the FT-SMR pathway to conventional crude oil production, using 1 MJ LHV as the functional unit. An additional assessment was also conducted by reporting the impact to 1 barrel. This is done to assess the effect that the add-on technology may have on the impact of current crude production. Converting associated gas using the FT-SMR pathway produces a synthetic crude with negative net GWP impacts. This is because the amount of avoided emissions is larger than the emissions due to the operation of the pathway. The remaining impact categories increase since the FT-SMR has additional intermediary steps, with added fuel energy needs, and additional process emissions. Moreover, the amount of natural gas required to produce 1 MJ of synthetic crude oil (abbreviated in the text as syncrude) results in larger impacts in the extraction phase, than those associated with the extraction of 1 MJ of conventional crude. The obtained syncrude has a GWP impact of -0.34 [-0.62, -0.14] kg CO2 eq/MJ, in comparison to 0.012 [0.009, 0.017] kg CO2 eq/MJ of conventional crude. A reduction of 8% to the impacts per daily barrel of crude (70.3 kg CO2 eq/barrel and 64.6 kg CO2 eq/barrel before and after using the FT-SMR pathway) was observed for a reduction of 34% of the total flared gas mass.