Low Emission Research Articles

Sustainable Utilization of Waste Glass Powder and Brick Dust as Cement Replacements: Effects on Mortar Performance and Environmental Benefits

With respect to sustainability, the material must maintain the quality and properties of concrete and be safe for human health, the environment, and long-time use. In recent times, the emission of CO2 from cement production processes has lessened with the passage of time due to its effect on the environment. In order to lessen the emissions and reduce environmental waste, available by-products with pozzolanic properties are applied. With respect to Portland limestone cement (CEMI II-BL), i.e., cement with lower carbon dioxide emissions and better workability than CEM I, the two main materials applied in the study as substitutes are brick dust (BD) and waste glass powder (WGP) bottles. Waste glass powder and brick dust, in quantities varying from 5% to 10%, 15%, and 20%, with a water/cement ratio of 0.35 and a 1.5% superplasticizer, were utilized to observe the effectiveness of BD and WGP on the flowability, compressive strength, flexural strength, water absorption, density, drying shrinkage, and fire resistance of the specimen mortar. The output shows that a WGP of 20% increased flowability compared to the control, whereas the inclusion of brick dust decreased it. At the age of 28, glass powder of 20% increased the compressive strength, while 20% brick dust exhibited a reduction; 15% WGP with 5% BD displayed the lowest absorption of water; and the density of all the samples proved to be much lower than the traditional mix, with 20% BD being the lowest (hereby labeled as light mortar). The 10% WGP with 10% BD displayed better resistance to fire, and the drying shrinkage of the sample was relatively low after several days of air curing. The impact on the environment and cost were considered without accounting for the transportation and manufacturing energy. As to the outcome of this experiment, we concluded that the use of both brick dust and glass powder with CEM II for producing mortar has proven very promising in a variety of different respects, including the mechanical and fresh features of mortar, with the combination of 5% WGP and 15% BD exhibiting the most potential in all of the acquired parameters.

Renewable energy strategy impacts on electricity system and carbon emissions in Hunan Province of China

This study investigates the impact of increasing renewable energy capacity on the power industry in Hunan Province, China, focusing on power demand, electricity generation, and CO2 emissions reductions. Using the Low Emission Analysis Platform (LEAP) model, five scenarios (BAU, RES, HEF, HST, and COP) were developed to assess the effects of renewable energy strategies from 2022 to 2035. The analysis considered renewable energy growth, energy storage, and efficiency improvements. The Comprehensive Optimization Scenario (COP) emerged as the most optimal, achieving a 48% share of renewable energy, 17% energy storage, and 23% efficient coal use, leading to significant CO2 emissions reductions while ensuring system flexibility and reliability. The study concludes that the COP scenario is the most effective in supporting a low-carbon transition and maintaining energy security. Practical implications include the need for policy support in areas such as diversified energy storage, distributed energy systems, V2G/V2X technologies, and smart grid development to enhance renewable energy integration and ensure sustainable development in Hunan.

Post‐Synthetic Graphitization and Photoluminescence Tuning of Carbon Dots from L‐Glutamic Acid

Carbon dots are promising luminescent nanostructures. Their availability, based on inexpensive precursors and their intrinsic fluorescent nature, place them as potential choices against traditional quantum dots in some applications. However, the carbon dots nature is nowadays not well defined and understood. They are usually hybrid nanomaterials in terms of structure and composition, which hinders the knowledge of their photoluminescence mechanisms. Herein, the solvent‐free pyrolysis of L‐glutamic acid by microwave synthesis leads to an incomplete graphitization of the precursor resulting in loose polymer‐like nanohybrids. Further experiments confirm that these carbon dots (CD) can be crosslinked and graphitized in a second heating step when using temperatures above 160 °C, reaching a plateau of graphitization over 200 °C. An exhaustive analysis by thermogravimetric analysis, Raman and X‐ray photoelectron spectroscopy highlights the structural changes undergo from 140 to 200 °C, where an increase of stability is observed due to the graphitization process. The condensation and decarboxylation reactions with loss of hydrophilic functional groups like amine and carboxylic acids explain the formation of sp2 domains and the concomitant loss of solubility. The annealed CD exhibit a broader and slightly red‐shifted emission band, with lower emission quantum yields, when compared to the initial nanohybrids.

Small emission sources in aggregate disproportionately account for a large majority of total methane emissions from the US oil and gas sector

Abstract. Reducing methane emissions from the oil and gas (oil–gas) sector has been identified as a critically important global strategy for reducing near-term climate warming. Recent measurements, especially by satellite and aerial remote sensing, underscore the importance of targeting the small number of facilities emitting methane at high rates (i.e., “super-emitters”) for measurement and mitigation. However, the contributions from individual oil–gas facilities emitting at low emission rates that are often undetected are poorly understood, especially in the context of total national- and regional-level estimates. In this work, we compile empirical measurements gathered using methods with low limits of detection to develop facility-level estimates of total methane emissions from the continental United States (CONUS) midstream and upstream oil–gas sector for 2021. We find that of the total 14.6 (12.7–16.8) Tg yr−1 oil–gas methane emissions in the CONUS for the year 2021, 70 % (95 % confidence intervals: 61 %–81 %) originate from facilities emitting <100kgh-1 and 30 % (26 %–34 %) and ∼80 % (68 %–90 %) originate from facilities emitting <10 and <200kgh-1, respectively. While there is variability among the emission distribution curves for different oil–gas production basins, facilities with low emissions are consistently found to account for the majority of total basin emissions (i.e., range of 60 %–86 % of total basin emissions from facilities emitting <100kgh-1). We estimate that production well sites were responsible for 70 % of regional oil–gas methane emissions, from which we find that the well sites that accounted for only 10 % of national oil and gas production in 2021 disproportionately accounted for 67 %–90 % of the total well site emissions. Our results are also in broad agreement with data obtained from several independent aerial remote sensing campaigns (e.g., MethaneAIR, Bridger Gas Mapping LiDAR, AVIRIS-NG (Airborne Visible/Infrared Imaging System – Next Generation), and Global Airborne Observatory) across five to eight major oil–gas basins. Our findings highlight the importance of accounting for the significant contribution of small emission sources to total oil–gas methane emissions. While reducing emissions from high-emitting facilities is important, it is not sufficient for the overall mitigation of methane emissions from the oil and gas sector which according to this study is dominated by small emission sources across the US. Tracking changes in emissions over time and designing effective mitigation policies should consider the large contribution of small methane sources to total emissions.

Experimental and computational fluid dynamics analysis on the influence of fuel injection pressure on engine's behavior of a gasohol based gasoline direct injection engine

AbstractThis work examines the impact of fuel injection pressure (FIP) on engine's behavior of a multi cylinder gasoline direct injection (GDI) engine using gasohol (85% gasoline+15% ethanol by mass) as fuel. The FIP was varied from 90r to 120 bar at 10 bar intervals with the fuel injection timing 320° before top dead center (BTDC). experiments were performed at variable power at a constant speed of 2500 rpm. Computational fluid dynamics (CFD) simulations were carried out for the above said conditions to understand engine's behavior. Considering the conventional FIP (i.e.90 bar), increasing the FIP showed improvement in engine's brake thermal efficiency (BTE) up to110 bar. The maximum BTE was observed as 33.5% at the engine power output of 21 kW (where as it was 27.2% with the FIP of 90 bar). CFD results confirmed the improvement in the air‐fuel mixing rate and swirl motion due to the increased FIP. The hydrocarbon (HC) and carbon monoxide (CO) emission were reduced with increased FIPs. CFD results on the HC and CO emissions indicated well agreement with the experiments. With the higher injection pressures, oxides of nitrogen (NOx) emissions showed an increase at all loads. The in cylinder pressure was observed to be higher with higher FIPs. It is concluded that increasing the FIP might improve performance and lower HC and CO emissions of a Gasohol based fuel in GDI engine. The optimized FIP of 110 bar could be recommended for the aforementioned engine's greatest performance without any modifications in the engine design while injecting the fuel at 320° BTDC. Increase in NOx emissions at higher injection pressure needs attention. The present study restricted the amount of ethanol as 15% by mass. Higher proportions of ethanol admissions require major modifications in the engine design.

Anionic Surfactants from Reactive Separation of Hydrocarbons Derived from Polyethylene Upcycling.

Chemical upcycling of polyethylene (PE) to long-chain alkylaromatics through tandem hydrocracking/aromatization has potential to provide value-added chemicals. However, the liquid product is a complex mixture of alkanes, alkylbenzenes, and polyaromatics, limiting its direct usability. The most valuable component of the product mixture is the alkylbenzenes because of their potential as precursors to anionic surfactants. In this study, a one-pot reactive separation is described. Sulfonating the product mixture from PE upcycling with silica sulfuric acid followed by neutralization with sodium hydroxide yields sodium alkylbenzenesulfonates (up to 93 mol % selectivity), along with a separate phase of lubricant-range hydrocarbons as a coproduct. Compared to petroleum-based sodium dodecylbenzenesulfonates, the reported PE-derived surfactant molecules show competitive physicochemical properties, including surface tension and interfacial tension. According to life cycle assessment, the described reaction strategy demonstrates 20% lower greenhouse gas emissions, when considering uses for the coproducts of PE upcycling, compared to conventional linear alkylbenzenesulfonates (LAS) manufacturing directly from petrochemical feedstocks.

Utilizing waste materials in concrete: A review on mechanical and sustainable performance

The construction industry consumes more natural resources than any other sector, necessitating sustainability practices. Utilizing waste materials in concrete addresses disposal challenges while enhancing sustainability. Many waste materials possess pozzolanic properties, improving concrete performance. This review aims to examine sustainable concrete incorporating waste materials such as fly ash (FA), silica fume (SF), recycled concrete aggregate (RCA), slag (S), waste perlite powder (WPP), groundnut husk ash (GHA), and nano silica (NS). The methodology involves a comprehensive analysis of life cycle assessment (LCA) studies, country-specific waste production, and concrete performance focusing on environmental and economic impacts. Results show that FA, SF, S, WPP, and NS enhance concrete's compressive strength, with SF yielding a 41% increase at a 12% substitution rate. Additionally, substituting FA can reduce carbon dioxide (CO2) emission by 68% and combining 5% SF and 15% FA lower CO2 emission by 16% compared to reference concrete. Furthermore, combining WPP and RCA results in a 17% cost reduction compared to reference concrete, while GHA substitution decreases cost by up to 30%. These findings highlight the potential of utilizing waste materials to improve mechanical performance, reduce environmental impact, and lower construction costs. The review suggests future research directions to further improve performance.

Investigating the Impact of Sustainable Rice Cultivation Processes (Alternative Wetting and Drying and Direct Seeded Rice) on the Indian Agrarian Economy and its Contribution to the UN’s Sustainable Development Goals

Sustainability has become an integral part of the United Nations’ development goals to ensure that the usage of resources in the present does not deplete the quality or quantity of resources available for future generations. The importance of sustainable agricultural practices has increased by manifolds when combating environmental and food security challenges. Rice cultivation in India alone comprises 26% of global rice production hence alternative rice farming methods are being explored for their potential contribution to fulfilling the Sustainable Development Goals (SDGs) and ensuring that the agrarian economy in India is growing at a sustainable rate.i This study aims to analyse the extent to which alternative sustainable rice cultivation methods (Alternative Wetting and Drying [AWD] and Direct Seeded Rice [DSR]) align with Social Development goals and impact the Indian economy. The research employs a qualitative analysis of secondary data from academic journals, government reports, and industry publications to evaluate the environmental and economic impacts of sustainable rice farming methods. The findings indicate that practices such as DSR and AWD significantly reduce water usage, lower greenhouse gas emissions, and improve soil health aligning with the SDGs (specifically SDG 12 [Responsible Consumption and Production] SDG 13 [Climate Change] and SDG 15 [Life on Earth]). Additionally, these practices are shown to offer long-term economic benefits for farmers through increased yields and reduced input costs and provide an external benefit to society by reducing the harmful impact of the wastage of water and greenhouse gas emissions on the environment. This study also discusses various government policies and private-sector projects that have incentivised farmers to adopt these sustainable rice cultivation practices. This research contributes to a deeper understanding of how sustainable agricultural practices can be leveraged to achieve global sustainability goals, offering a model for integrating environmental and economic objectives in agricultural policy.

The Impact of Trade Openness on Carbon Emissions: Empirical Evidence from Emerging Countries

Emerging countries are the main source of new CO2 emissions and the major net carbon importers, and they have also become an important part of the global trade pattern. In this study, the impact of trade openness on CO2 emissions was investigated by approaches such as fully modified least squares (FMOLS), dynamic ordinary least squares (DOLS), and pooled mean group-autoregressive distributive lag (PMG-ARDL) methods. Further estimations were conducted by employing methods such as DCCEMG (dynamic common-correlated effect mean group) and Driscoll–Kray to strengthen the robustness of the results. Moreover, the Granger causality between trade openness and CO2 emissions was tested by using the Dumitrescu–Hurlin method. Conclusions can be drawn as follows: First, economic growth, energy consumption, trade openness, and CO2 emissions are all interconnected in the long term. Specifically, higher levels of economic growth and trade openness are associated with lower CO2 emissions, whereas energy consumption contributes to higher emissions. However, in the short term, economic growth and energy consumption lead to an increase in CO2 emissions, while trade openness does not have a significant impact. Moreover, there is a two-way Granger causality between trade openness and CO2 emissions. Additionally, economic growth and energy consumption have an indirect effect on CO2 emissions by influencing trade openness. Given these findings, emerging market countries should focus on enhancing their service sectors, promoting technological advancements, and fostering international collaboration in green technologies. By actively engaging in efforts to combat climate change, these countries reach a point where trade expansion and carbon reduction are achieved.

Study on enhancement of imaging effect of silicon-based up-conversion NIR detector by cascade material fusion method

The nonlinear frequency conversion of the up-conversion materials facilitates the conversion of near-infrared (NIR) into visible, which can be detected by the silicon-based detector. However, the low emission intensity of up-conversion materials limited the application. In this paper, a cascade material fusion (CMF) method was proposed to increase the visible emission intensity, which enhanced the imaging of up-conversion silicon-based NIR detectors. The energy level transition mechanism of CMF suggested that the host material (HM) could realize four stimulated emissions under 1550 nm excitation to enhance the up-conversion emission intensity of HM. The silicon-based NIR imaging detectors based on CMF and HM were prepared, and it was observed that the fusion ratio of doped material (DM) and HM has a significant impact on the silicon-based NIR imaging detector upon 1550 nm excitation. The enhanced imaging effect was optimal when the fusion ratio of DM and HM was 0.125, which enhanced about 3.4 times by comparison with the HM detector.

CO2e Life-Cycle Assessment: Twin Comparison of Battery–Electric and Diesel Heavy-Duty Tractor Units with Real-World Data

In 2023, the EU set the target to reduce greenhouse gas (GHG) emissions by 55% until 2030 compared to 1990. The European Transport Policy sees battery–electric vehicles as a key technology to decarbonize the transport sector, so governments support the adoption through dedicated funding programs. Battery–electric trucks hold great potential to decarbonize the transport sector, especially for high-impact, heavy-duty trucks. Theoretical life-cycle assessments (LCA) predict a lower CO2e emission impact from battery–electric trucks compared to conventional diesel trucks. Yet, one concern repeatedly mentioned by potential users is the doubt about the ecological advantage of battery–electric vehicles. This is rooted in the problem of a much higher CO2e impact of the lithium-ion batteries production process. As heavy-duty trucks have a much larger battery, the hypothec in the construction phase of the vehicle is significantly higher, which must be regained during the use phase. Although theoretical assessments exist, CO2e evaluations using real-world application data are almost nonexistent, as the technology is at the very start of the adoption curve. Exemplary is the fact that there were only 72 registered battery–electric heavy-duty tractor trucks throughout the whole of Germany at the start of 2023. This paper aims to deliver one of the first real-world quantifications using operational data for the actual reduction impact of battery–electric heavy-duty trucks compared to diesel trucks. This study uses the methodology of the life-cycle assessment approach according to ISO 14040/14044 to gain a systematic and holistic technology comparison. For this LCA, the system boundaries are considered from cradle to cradle. This includes the production of raw materials and energy, the manufacturing of the trucks, the use phase, and the recycling afterward. The research objects of this study are battery–electric and diesel Volvo FM trucks, which have been in use by the German freight company Nord-Spedition GmbH since May 2023. The GREET® database is used to assess the emission impact of the material production and manufacturing process. The Volvo tractor trucks resemble a critical case, as the vehicles have a battery size of 540 kWh—around 11 times larger than a usual passenger car. The operation data is directly provided by the logistics company to observe fuel/electricity consumption. Other factors are assessed through company interviews as well as a wide literature research. Finally, a large question mark concerning total emissions lies in the cradle-to-cradle capabilities of large-scale lithium-ion batteries and the electricity grid mix. Different scenarios are being considered to assess potential disposal or recycling paths as well as different electricity grid developments and their impact on the overall balance. The findings estimate the total emissions reduction potential to range between 34% and 69%, varying with assumptions on the electricity grid transition and recycling opportunities. This study displays one of the first successful early-stage integrations of battery–electric heavy-duty trucks into the daily operation of a freight company and can be used to showcase the ecological advantage of the technology.

Analysis of the Odor Levels at the Closest Receptors Depending on the Stack Terminal Types

This paper presents the results of a numerical analysis for evaluating the effects of different stack terminal configurations on the odor levels estimated at the receptors located close to the plant. Stack terminals may be of different types, for example vertical unobstructed, vertical with rain cap, horizontal, gooseneck or with any slope with respect to the vertical. The comparison between CALPUFF and LAPMOD with vertical unobstructed stacks, rain capped stacks and different emission temperatures shows that the results are comparable, even though there is a tendency of LAPMOD to underpredict when vertical unobstructed stacks are used. A detailed numerical analysis has then been performed with the LAPMOD dispersion model, which adopts a numerical plume rise scheme capable to simulate releases with any orientation. Two different sites have been considered, both located in northern Italy: one with almost flat orography, and one with relatively complex orography. The results show that the choice of the stack terminal has important effects on the odor levels predicted at the closest receptors. The vertical unobstructed stack always has a smaller impact than all the other terminal types, particularly for low emission temperatures.

Investigating factors influencing CO2 emissions in selected G20 countries

This study aims at identifying the factors that influence CO2 emissions in some G20 countries. It examines various possibilities such as electricity consumption, foreign investments, fuel and metal exports, economic growth, population growth, renewable energy consumption, trade, urbanization, and even the effects of the global economic crisis of 2008. The results show that increased electricity consumption, economic growth, and population increase result in higher levels of CO2 emissions which demonstrates the environmental impact of industrialization and urbanization. Conversely, the use of renewable energy and foreign investment are correlated with lower emissions which proves that a shift towards cleaner energy and sustainable investments can be effective. The findings of the study also point towards the fact that the G20 countries need to shift towards the use of renewable energy, enhance energy efficiency, and encourage the development of sustainable urban environments. It provides a practical approach for the policymakers to follow for emission reduction along with promoting economic growth in a sustainable manner.

Heterogeneous multi-agent deep reinforcement learning based low carbon emission task offloading in mobile edge computing

Heterogeneous multi-agent deep reinforcement learning based low carbon emission task offloading in mobile edge computing

Development of sustainable concrete with pulverized coal bottom ash for low cost and carbon emission

Development of sustainable concrete with pulverized coal bottom ash for low cost and carbon emission

Sustainable stabilization/solidification of electroplating sludge using a low-carbon ternary cementitious binder

Electroplating sludge (ES), due to its high dosages of heavy metals (HMs), is classified as hazardous waste, presenting risks to both health and environment. Stabilization/solidification (S/S) technology is extensively applied in ES treatment. This study designs a low-carbon ternary cementitious binder, limestone calcined clay cement (LC3), for S/S treatment of ES and investigates the immobilization mechanism of HMs in the crystalline products and calcium alumino-silicate hydrate (C-A-S-H) within LC3. Results show that CrO42- and Cd2+ are primarily stabilized in aluminate crystalline products by replacing SO42- and Ca2+ in the double-layered plate structure, respectively. The remaining CrO42- is captured by the (SiOOH)2AlCa⁺ groups in C-A-S-H generated from substitution of aluminum tetrahedra to bridging silicon tetrahedra. For positively charged Cd2+, it is mainly stabilized through ion exchange with Ca2+ on the C-A-S-H chains. The pozzolanic reaction of calcined clay increases the Al/Ca and Si/Ca atomic ratios in C-A-S-H, enhancing the immobilization efficiency of C-A-S-H to CrO42- and Cd2+. The synergistic effect of calcined clay and limestone, along with the dissolution of aluminosilicates in calcined clay, changes the structure and composition of hydration products, facilitating the chemical binding of CrO42- and Cd2+ by aluminate products. Moreover, the extra hydration products generated by the pozzolanic reaction and the formation of numerous carboaluminate phases strengthen the physical encapsulation performance to HMs. Regarding actual S/S performance, multi-scale evaluation results show that the designed LC3 binder achieves sustainable S/S of ES with high strength, low carbon emission, low cost, and low energy consumption.

Converting cellulose to biogas with anaerobic digestion at incubation temperatures of 5 °C difference in the effort for efficiency and low carbon emission

Converting cellulose to biogas with anaerobic digestion at incubation temperatures of 5 °C difference in the effort for efficiency and low carbon emission

Ticks jump in a warmer world: Global distribution shifts of main pathogenic ticks are associated with future climate change.

In recent decades, the threats of ticks and tick-borne diseases (TBDs) increased extensively with environmental change, urbanization, and rapidly changing interactions between human and animals. However, large-scale distribution of tick and TBD risks as well as their relationship with environmental change remain inadequately unclear. Here, we first proposed a "tick-pathogen-habitat-human" model to project the global potential distribution of main pathogenic ticks using a total of 70,714 occurrence records. Meanwhile, the effects of ecological factors and socio-economic factors driving the distribution pattern were evaluated. Based on this, the risk distribution of TBDs was projected by large-scale "tick-pathogen-disease" analysis. Furthermore, the distribution shifts of tick suitability were projected under different shared socio-economic pathways in the future. Our findings demonstrate that warm temperate countries (e.g., the United States, China and European countries) in the Northern Hemisphere represent significant high risk regions for ticks and TBDs. Specifically, solar radiation of January emerges as the main decisive factor determining the risk distribution pattern. Future shifts of tick suitability showed decrease trend under low greenhouse gas emission scenarios but increase trend under high scenarios. These suitability shifts were significantly correlated with future temperature- (9 species) and precipitation- (19 species) related factors. Collectively, in this study we first shaped the global risk distribution of main ticks and TBDs as well as tick suitability shifts correlated with future global climate change, which will provide helpful references for disease prevention and administration. The methods proposed here will also shed light on other emerging and recurrent zoonotic diseases (e.g., COVID-19, monkeypox) in the future.

Low impact emissions H2 production via biogas steam reforming in a foam structured membrane reactor: Energy efficiency and exergy analyses, and H2 production cost assessment

Low impact emissions H2 production via biogas steam reforming in a foam structured membrane reactor: Energy efficiency and exergy analyses, and H2 production cost assessment

Reducing methane emissions by developing low-fumarate high-ethanol eco-friendly rice.

Methane in rice paddies is mainly produced by methanogenic communities feeding on carbon from root exudates and debris. However, the dominant root secretion governing methane emissions is not yet identified after decades of studies, even though secreted carbohydrates and organic acids have been shown to contribute to methane emissions. In this study, we discovered that fumarate and ethanol are two major rice-orchestrated secretions and play a key role in regulating methane emissions. Fumarate released in the rhizosphere is metabolized by microorganisms, supporting the growth of methanogenic archaea that produce methane as an end carbon product, while ethanol mitigates methane emissions through inhibition of methanogenic activity and growth as well as reducing fumarate synthesis in the rice root. Furthermore, we elucidated the route of fumarate metabolism in the anoxic rhizospheric zone. We found that fumarate in the rice root is produced from acetate via propionate and succinate, and when released into soil directly is oxidized to propionate before conversion via acetate into methane as the end product. The knowledge on fumarate and ethanol metabolism in rice was then used for hybrid breeding of new rice varieties with the property of low methane emission. Cultivation of these novel rice lines or employing our findings for rice cultivation managements showed up to 70% reductions in methane production from seven paddy field sites during 3 years of cultivation trials. Taken together, these findings offer great possibilities for effective mitigation of the global climatic impact of rice cultivation.