Emission Intensity Research Articles

Concentration- and temperature-dependent luminescence mechanisms and fluorescence dynamic temperature sensing of NaY(MoO4)2:Tb3+ phosphors

High-temperature solid-state reaction technique was used to prepare NaY(MoO4)2:Tb3+ phosphors with different Tb3+ concentrations. XRD patterns showed that the prepared samples contained only single-phased compound NaY(MoO4)2. The concentration-dependent green luminescent intensity of Tb3+ was studied, and it was found that the concentration quenching process is in charge of Ozawa's model. The concentration-effect of luminescence decay of 5D4 level was explained by the Auzel's self-generated quenching theory. Starting from the Reisfeld's theory, the analysis on the luminescence decays also indicated exchange interaction was responsible for the concentration quenching. Temperature dependences of the green emission intensity and decay were comprehended based on the crossover mechanism. A novel temperature sensing technique rooting in the fluorescence dynamics of 5D4 level of Tb3+ in NaY(MoO4)2 was proposed, and the absolute and relative sensitivities were deduced and assessed.

Well-to-Wheel emissions of electric vehicles in Türkiye and emission mitigation by renewable penetration

Automotive technology is currently on the verge of transitioning to electric vehicles, and both the impact of these vehicles on electricity consumption and their environmental performance are the focus of significant interest. In this paper, the emission impacts based on the use of electric vehicles are analyzed using the Well-to-Wheel methodology. In order to evaluate electric vehicle emissions, emissions based on electricity generation and consumption are first determined. Emission intensities are found in gCO2e/kWh for electricity consumption and gCO2e/km for battery electric vehicles. Well-to-wheel emissions are found 172.2 and 89.1 gCO2e/km for conventional and electric vehicles, respectively. With the renewable penetration in electricity generation, the emission intensity will be lower, which means that the emissions of electric vehicles will be further reduced. Thus, a renewable energy supported charging station is simulated and it is shown that emission intensities can be reduced by 60 %. It is concluded that Türkiye should focus primarily on renewable energy sources and then nuclear energy in order to meet the increasing electricity demand and reduce emission intensities.

Tunable emission and energy transfer of Tb3+/Eu3+ co-doped single-phase Sr2MgSi2O7 glass-ceramics

In this work, the Tb3+/Eu3+ co-doped 30SrO-10MgO-50SiO2-5TiO2-5B2O3-1Tb2O3-xEu2O3 (x = 0-2.5 mol% at 0.5 intervals) glasses were prepared by the melt-quenching method, and the single-phase Sr2MgSi2O7 glass-ceramics were obtained after heat treatment. The structural and fluorescence performance of the glasses and glass-ceramics were examined using DSC, XRD, SEM, FTIR, and photoluminescence spectra, and the energy transfer process between Tb3+ and Eu3+ was systematically investigated. With increasing Eu2O3 contents, the thermal stability of the glasses is enhanced and the density of both the glasses and the glass-ceramics rises. The XRD and SEM results reveal the precipitation of the irregular spherical Sr2MgSi2O7 microcrystals with a grain size roughly within 0.5-1 μm. Under 376 nm excitation, the overall emission intensity and lifetime of Eu3+ ions increase with increasing Eu2O3 contents, and the energy transfer efficiency reaches 58.74% from 31.07%. According to the Dexter model, the energy transfer process between the Tb3+ and Eu3+ is dominated by the quadrupole-quadrupole interactions. By varying the Eu2O3 contents, all the glass-ceramics exhibit higher color purity (82.06-96.27%), and their chromaticity coordinates shift from yellowish green towards reddish orange, which is potentially promising for w-LEDs.

Carbon emission scenario analysis of data centers in China under the carbon neutrality target

The low-carbon transformation of data centers is of great significance to achieve the goals of carbon peaking and carbon neutrality. This study compared and analyzed the overall situation of data centers in China. Based on China's CO2 emission and intensity targets in key years, the four variables of energy efficiency improvement rate, nonfossil energy consumption proportion, negative emission technology intensity, and waste energy utilization rate were introduced, and a net zero emission path model of data centers was established. Using scenario analysis to predict the total CO2 emissions and emission intensity from 2021 to 2060, three emission reduction path scenarios were obtained. Results showed that the energy consumption of data centers increased gradually, the carbon emissions first increased and then decreased, and the power usage effectiveness (PUE) of the data centers decreased gradually. The carbon peak time of the three scenarios is 2030, and the time for carbon neutrality is 2055, 2053, and 2051 in three scenarios. The data center industry should further improve the energy efficiency utilization rate, increase the proportion of nonfossil energy consumption, strengthen the technological innovation of carbon capture and storage, enhance the level of carbon sink, and optimize the utilization rate of waste energy.

ESIPT+TICT-based Near-IR Detection of Al3+ and F- in Live Cells: Molecular Docking with Acetylcholinesterase.

The interplay of ESIPT+TICT mechanisms in 1,8-naphthalimide-hydroxyquinoline (NQ-OH) molecular rotor were reported for the near-IR 'turn-on' emission (λmax 600 nm) and ratiometric (A405nm/A345nm) absorbance-based detection of Al3+ ions in aqueous medium and live cells which were supported by NMR, IR and CV techniques. The limit of detection (LOD) for Al3+ ions is 100 nM and 14.57 nM. The self-assembled spherical aggregates of NQ-OH transformed into cuboidal aggregates upon coordination with Al3+ ions supported by microscopic and dynamic light scattering (DLS) techniques. The complex NQ-OH+Al3+ was further used for the secondary detection of F- ions in aqueous medium via displacement approach with LOD as low as 2.67 nM. A deeper study revealed that the NQ-OH is a solvatochromic dye. Probably, the NQ-OH either in the aggregated state or in the coordination state with Al3+ ions, showed an increase in the emission intensity at 600 nm due to inhibition of the ESIPT process and trigger of the TICT process. We have demonstrated the utility of NQ-OH for the detection of Al3+ ions and NQ-OH+Al3+ complex for the detection of F- ions in MCF7 live cells. We have also discussed the molecular docking studies of NQ-OH with acetylcholinesterase enzyme.

Soil pH-dependent efficacy of DMPP in mitigating nitrous oxide under different land uses

The emission pathways and intensities of nitrous oxide (N2O) vary across land uses, and the efficacy of mitigation measures may also differ. To investigate the key factors influencing the effectiveness of the nitrification inhibitor 3,4-Dimethylpyrazole phosphate (DMPP) in mitigating N2O under various land use conditions, we collected ten pairs of soils from tea plantations and adjacent cultivated land for laboratory incubation. As a complementary study, we conducted a meta-analysis based on 261 pairs of observations from 40 incubation studies to investigate the determinants of soil N2O mitigation by DMPP and to validate our experimental results. Results of the incubation experiment showed that DMPP was significantly less effective in mitigating N2O in tea plantation soils (73%) than in cropland soils (82%). Soil pH is a key factor influencing DMPP efficiency under different land use conditions. The lower pH of acidic tea plantation soils resulted in lower abundance and activity of ammonia-oxidizing bacteria (AOB). Under these low pH conditions, heterotrophic nitrification became an important source of N2O emissions in acidic tea plantation soils. As DMPP primarily inhibits AOB, it was less effective against heterotrophic nitrification, which likely contributed to its reduced efficacy in tea plantation soils compared to cropland soils. Our meta-analysis further confirmed the critical role of soil pH in determining DMPP effectiveness. The effect of soil pH on DMPP efficacy was mainly attributed to its regulation of heterotrophic and AOB-derived nitrification. These findings suggest that the field efficacy of DMPP in N2O abatement in tea plantations requires further investigation. Given the significant contribution of heterotrophic nitrification to N2O emissions in strongly acidic tea plantation soils, alternative N2O mitigation strategies should be explored.

Geo-political risks, uncertainty, financial development, renewable energy, and carbon intensity: Empirical evidence from countries at high geo-political risks

Geopolitical risks and uncertainty negatively affect the economy and environmental quality. High geopolitical risks and high uncertainty increase carbon emission intensity by increasing dependence on fossil fuels. However, research in this area is still in its infancy and more empirical evidence is needed to justify the causal link. This research examines the causal mechanism linking geopolitical risk, uncertainty, financial development, renewable energy, and carbon intensity in a sample of eighteen countries with high geopolitical risk between 1985 and 2021. The selected countries have a high intensity of geopolitical risks due to internal and external conflicts that have worsened in recent years. We employ cointegration techniques from Hatemi-J [1] and Maki [2] in the presence of structural breaks, fully modified ordinary least squares (FMOLS), canonical cointegration regression (CCR) models, and static time-variant Granger causality (1969) test. We find robust empirical evidence that geopolitical risk, financial development, renewable energy, uncertainty, and carbon intensity have a cointegrating relationship in the presence of structural breaks. Results from FMOLS and CCR models indicate that carbon intensity responds differently to changes in geopolitical risk, renewable energy, uncertainty, and financial development. Environmental and energy policymakers should mitigate carbon intensity through long-run rather than short-run mechanisms to achieve SDG12 and SDG13.

Optimizing sustainable development in arid river basins: A multi-objective approach to balancing water, energy, economy, carbon and ecology nexus

The ongoing water crisis poses significant threats to the socioeconomic sustainability and ecological security of arid and semi-arid river basins. Achieving Sustainable Development Goals (SDGs) within a complex socio-ecological nexus requires effective and balanced resource management. However, due to the intricate interactions between human societies and environmental systems, the tradeoffs and synergies of different SDGs remain unclear, posing a substantial challenge for collaborative management of natural resources. Here we introduce a gray fractional multi-objective optimization (GFMOP) model to balance multi-dimensional SDGs through a novel water–energy–economy–carbon–ecology nexus perspective. The model was applied to a typical arid river basin in Northwest China, where thirty-two scenarios were explored, considering factors such as shared socioeconomic pathways, carbon removal rates, water conveyance efficiencies, and ecological requirements. The results reveal a strong tradeoff between marginal benefit and carbon emission intensity, indicating that improving the economic efficiency of water use can simultaneously reduce emissions and protect the environment. Given the immense power generation potential, wind power development should be prioritized in the future, with its share in the energy structure projected to increase to 23.3% by 2060. Furthermore, promoting carbon capture technologies and expanding grassland coverage are recommended to achieve regional carbon neutrality, contributing 39.5% and 49.1% to carbon absorption during 2021–2060, respectively. Compared with traditional single-objective models, GFMOP demonstrates a superiority in uncovering interrelationships among multiple SDGs and identifying compromised alternatives within the compound socio-ecological nexus. The model also provides detailed strategies for resource allocation and pollutant control, offering valuable guidance to policymakers and stakeholders in pursuing sustainable and harmonious watershed management.

The use of infrared thermography as an indicator of methane production in hair sheep.

Infrared thermography may be an alternative technology for measuring the amount of CH4 produced and has the advantages of low cost, speed and efficiency in obtaining results. The study's objective was to determine if the infrared thermography is adequate for predicting the emission of CH4 in hair sheep and the best time after feeding to carry out the measurement. Twelve Santa Inês lambs (females, non-pregnant, with twelve months old and mean body weight of 39.3 ± 2.1kg) remained for two days in respirometric chambers, in a semi-closed system, to determine the CH4 production. The animals were divided into two treatments, according to the diet provided. During this period, seven thermographic photographs were taken, at times - 1h, -0.5h, 0h, 0.5h, 1h, 2h, 3h, 5h, and 7h, according to the feeding time, defined as 0h. CH4 production was measured over 24h. Thermographic images measured the maximum, minimum, average and point temperatures at the left and right flanks. The temperature difference between the left and right flanks (left minus right) was calculated each time. Pearson correlation coefficients, multiple regression and principal component analysis were carried out in SAS®. The best prediction of emission intensity of CH4 (kg of CH4 per dry matter intake) was obtained at 3h after feeding: CH4/DMI = 13.9016-0,38673 * DifP2 + 3.39089 * DifMed2 (R² = 0.48), using the difference between left and right flanks for point and average temperature measures. Therefore, infrared thermography can be used as an indicator of CH4 production in hair sheep three hours after feeding.

Energy Efficiency and Greenhouse Gas Emissions: A Panel ARDL Model of Top Five Emitters in Africa

The Paris Agreement has mandated drastic decarbonization by developed and developing economies. Many of the top African emitters are now exploring drastic restructuring of the production processes in a way that promotes energy utilization efficiency. This is critical for ensuring an environmentally benign growth process. This study presents a unique addition to the body of existing knowledge by analysing the effect of some indicators of energy efficiency on three indicators of environmental quality among the top five emitters of GHG in Africa. The data were from the World Development Indicators (WDI), covering the 1990-2020 periods for South Africa, Egypt, Nigeria, Algeria, and Libya. The panel Autoregressive Distributed Lag (ARDL) model was used for data analysis. The results showed that all the included series were stationary at first difference. The optimum lag lengths were determined independently in STATA 17 software, and the most frequent lags across the countries were selected. The Hausman test revealed that the pooled mean group (PMG) estimation was preferred to other estimators. The results showed that in the long-run, particulate emission damages, CO2 intensity, and energy use intensity positively impacted GHG emissions, while GDP per capita and renewable energy utilization produced mixed results. In the short run, the error correction mechanism parameters were all significant (p<0.01) in Libya for all emission indicators, while Algeria showed significance (p<0.01) in total GHG and CO2 per capita models. The coefficient of particulate emission damages significantly reduced (p<0.01) total GHG emissions in Libya and Nigeria and renewable energy significantly increased (p<0.01) GHG emissions in South Africa but reduced them in Nigeria. Also, CO2 emission intensity significantly (p<0.01) and positively impacted GHG emissions in South Africa, Egypt, Libya, and Nigeria, while electricity power transmission losses increased total emissions and CO2 emissions in Libya and Algeria. It was concluded that initiatives to reduce GHG emissions should focus on developing countries’ sensitivity to emission damages, and promotion of initiatives for using renewable energies. Also, promotion of energy efficiency across industries offers a prospect for ensuring environmental sustainability.

Study of condensable particulate matter from stationary combustion sources: Source profiles, emissions, and impact on ambient fine particulate matter

Although significant progress has been made in controlling emissions from stationary combustion sources in China over the past decade, understanding of condensable particulate matter (CPM) emissions from these sources and their impact on ambient PM2.5 remains limited. In this study, we established the source profiles and emission inventories of CPM from coal-fired industrial boilers (CFIBs), coal-fired power plants (CFPPs), and iron and steel industry (ISIs) for the Yangtze River Delta (YRD) region of China; furthermore, the air quality model (Community Multiscale Air Quality, CMAQ) was used to evaluate the impact of their CPM emissions from these three types of stationary combustion sources on ambient PM2.5 during Feb. 2018, a month characterized by elevated PM2.5 concentrations. The results indicated that CPM emissions from these three sources in the YRD region before and after the implementation of the ultra-low emissions (ULE) policy amounted to 109,839 and 43,338 tons, respectively, with particularly high emission intensity along the Yangtze River. The implementation of CFPPs ULE policy was shown to reduce the impact of CPM emissions from the three stationary sources on monthly PM2.5 concentrations from 0.92 μg/m3 to 0.41 μg/m3 (with a maximum of 5.35 μg/m3), a reduction that exceeded the decrease of 0.31 μg/m3 in PM2.5 concentrations resulting from the emission reductions of conventional pollutants (FPM, SO2 and NOx). CPM emissions from the three stationary sources were found to increase the PM2.5 by 0.68 μg/m3 during pollution periods. The largest components of PM2.5 contributed by CPM emissions from stationary combustion sources were sulfate, organic carbon, and nitrate, accounting for 21.4 %, 21.1 %, and 18.2 %, respectively. Particularly, CPM's contributions to PM2.5 varied by altitude, with a relatively large impact at altitudes between 220 and 460 m. Attention should be given to CPM emission control, with particular priority placed on implementing ULE measures for ISIs and CFIBs.

Realization of blue-red dual-emission via energy transfer in Na3KMg7(PO4)6: Eu2+, Mn2+ phosphor for plant growth application☆

A blue-red dual-emitting phosphor, Na3KMg7(PO4)6: Eu2+, Mn2+ was developed in this study. Eu2+ acts as a sensitizer ion in Na3KMg7(PO4)6: Mn2+, which significantly improves the undesirable luminous efficiency of Mn2+. The energy transfer between Eu2+ and Mn2+ significantly boosts both internal quantum efficiency (IQE) and external quantum efficiency (EQE) of the phosphor, achieving values of 72.5% and 42.6%, respectively. Additionally, the phosphor demonstrates exceptional thermal stability, at 150 °C, maintaining 71.49% of its initial emission intensity. The emission spectrum of the phosphor closely matches the chlorophyll’s absorption spectra, with similarities of 75.06% and 94.52%, respectively. This was further confirmed through a fabricated LED with a n-UV chip (395 nm). To further assess the potential for agritech applications, a light-conversion film incorporating the developed phosphor in PDMS glue was prepared. An outdoor cultivation trial with Chlorella showed that the algae's growth rate improves by 27.3% relative to a control group. These results reveal the significant potential of the Na3KMg7(PO4)6: Eu2+, Mn2+ phosphor for enhancing plant growth in practical applications.

The highly efficient and stable near-infrared phosphor Ca3MgSnGe3O12: Cr3+ for multifunctional application

The investigation of efficient and stable near-infrared (NIR) luminescent materials is crucial for rapidly developing near-infrared spectroscopic techniques. Herein, NIR phosphors Ca3MgSnGe3O12: Cr3+ with ultra thermal stability and high internal quantum yield (IQY) are explored. The emission intensity remained at 91.75 %@423 K of room temperature and the IQY/EQE reaches 91.41 %/34.04 % after doping the H3BO3 flux agent for optimization. Moreover, a single luminescence center was identified by cryogenic photo luminescence spectroscopy (PL) from 4 K to 300 K and lifetime decay curve. Importantly, NIR light can easily removes all kinds of background interference that cannot be easily eliminated by visible light, which is not only widely used in night vision and biological tissue penetration, but also has higher application prospects in NIR fingerprint detection. Moreover, it clearly displays high level of fingerprint details under high temperature conditions and after water immersion, thus it is perfectly suited for using in Automatic Fingerprint Identification System (AFIS) systems. Therefore, Ca3MgSnGe3O12: Cr3+ NIR pc-LEDs have great potential for latent fingerprint detection at actual crime scenes.

High-efficiency RbASiF6:Mn4+ (A = K, Cs) phosphors obtained by one-step green synthesis method

Red-emitting Mn4+-doped fluoride phosphors are recognized as promising materials for high-performance warm white light-emitting diodes (WLEDs). However, the extensive use of toxic hydrofluoric acid in traditional synthesis methods hinders their development and commercialization. Furthermore, the traditional solid-phase method often has cumbersome sintering steps, high temperature, long holding time, and certain safety hazards, so it is very necessary to develop a green synthesis method with simple steps and low energy consumption. In this study, a low-temperature solid-state method is proposed to synthesize RbASiF6:Mn4+ (A = K, Cs) phosphors by one step. Optimal emission intensities were observed at Mn4+ concentrations of 1.2 % in RbKSiF6 and 2.1 % in RbCsSiF6. These phosphors demonstrated high thermal stability. At 423 K, the photoluminescence intensities of RbKSiF6:1.2 %Mn4+ and RbCsSiF6:2.1 %Mn4+ reached 114 % and 87 % of their respective values at room temperature. Meanwhile, the chromaticity shifts were almost negligible, and high color purity was achieved for both phosphors. The electro-optical performance of WLED devices utilizing these phosphors, in combination with YAG:Ce3+ and GaN chips, showed high color rendering indices (CRI) and low correlated color temperatures (CCT) across varying currents. Specifically, under a driving current of 20 mA, the device incorporating RbKSiF6:1.2 %Mn4+ exhibited a CRI of 94 and a CCT of 3732 K, with a luminous efficacy of 61 lm/W. These findings highlight the potential of green-synthesized RASFM phosphors in advancing the application of warm WLEDs.

GHG emission quantification and reduction pathway of subway shield tunnel engineering: a case study on Guangzhou Metro, China.

The shield method is a commonly used construction technique in subway tunnel engineering. However, studies on greenhouse gas (GHG) emissions specifically in subway shield tunnel engineering are lacking. This study aims to investigate the GHG emission characteristics and GHG reduction pathways during the construction period of subway shield tunnels. Firstly, based on the life cycle assessment (LCA) method, a greenhouse gas (GHG) emission quantification model for the shield tunnel construction period was developed using a multi-level decomposition of construction. Then, the GHG emission level and intensity during the construction period of a case project are quantified, and its emission characteristics and GHG reduction potential points are assessed. Finally, a comprehensive path for GHG reduction in subway shield tunnel engineering is proposed. The research results indicate that constructing 1 km of subway shield tunnel can generate 19,294.28 t CO2eq. Among these, material production element dominates the emissions with a percentage of 89.05%, while transportation and mechanical construction elements contribute 1.81% and 9.14%, respectively. From the structure perspective, the main structure contributes 88.73% of total emissions, while the ancillary structure contributes 11.27%. Among them, the working shaft and tunnel segments are the main sources of emissions for the main structure, accounting for 23.65% and 65.08%, respectively. Connecting channel and end reinforcement are the main emission sources of the ancillary structures, accounting for 43.63% and 31.30%, respectively. These findings provide a scientific foundation for the environmentally friendly transformation of urban railway development regarding pursuing "carbon peaking and carbon neutrality" strategic goals.

CATHODIC AND ANODIC PLASMA ELECTROLYSIS ON NITRATE SYNTHESIS

Nitrogen fixation using plasma electrolysis is an alternative in the production of liquid nitrate fertilizer which is safe for the environment because it does not produce emissions that pollute the environment. The effectiveness of nitrate production is shown from the position of plasma formation at cathodic and anodic levels. This study aims to analyze the comparison of cathodic and anodic plasma electrolysis levels in producing nitrate. Current-voltage characterization is carried out to determine the position of plasma formation. The glow discharge of the cathodic plasma is achieved after the critical voltage (280 V) is lower than that of the anodic plasma (650 V). Measurement of emission intensity using electron spin resonance to determine reactive species that play a role in the formation of nitrate in cathodic and anodic plasma. Nitrate formation is influenced by reactive species in the form of N, N2*, N2+, •OH, •H and •O, especially reactive species of nitrogen and •OH are needed to form nitrate both from the NO pathway (anodic plasma) and from the ammonia pathway (cathodic plasma). The results of this study showed that anodic plasma electrolysis was more effective for nitrate synthesis. Nitrate produced from anodic plasma is 1889 mg L-1, greater than cathodic plasma as much as 213 mg L-1.

Sustainability transitions in the agri-food system: Evaluating mitigation potentials, economy-wide effects, co-benefits and trade-offs for the case of Austria

As a major source of greenhouse gas (GHG) emissions and with a substantial potential of carbon storage, agriculture and food (agri-food) systems play a two-fold role in achieving the Paris goal of well below 2 °C of global warming. Against this background, this paper assesses the mitigation potentials, economic effects, co-benefits and trade-offs of biophysically feasible transitions of the Austrian agri-food system. By combining biophysical accounting with a comparative-static multi-sectoral computable general equilibrium model, we assess both supply- and demand-side driven transition scenarios. These scenarios entail substantial changes in the Austrian agri-food system, mitigating between 70 and 110% of GHG emissions relative to the reference pathway in 2050, with lower emission intensities from agricultural practices and enhanced sinks through afforestation. Two out of three scenarios lead to economy-wide costs of up to 1% of gross domestic product. Despite these small changes at the macroeconomic scale, output effects within the Austrian agri-food sectors are substantial, with primary production and manufacturing of plant-based products emerging as winners in terms of sectoral revenue, while animal-based primary production and manufacturing lose. The agri-food system transitions considered create health co-benefits, but reveal trade-offs between mitigation potentials, biodiversity conservation and economic effects.

Luminescence enhancement behavior of KSr1.96Sm0.04Nb5O15/PVDF composite thick film after electric polarization

A novel composite thick film exhibiting luminescent enhancement behavior was prepared using Sm3+ doped KSr2Nb5O15 ferroelectric microcrystals and polyvinylidene difluoride (PVDF) polymer via a tape-casting technology. After compositing with PVDF, the thick film retained the ferroelectric polarization behavior, and the PVDF phase had negligible impact on the reflectivity and optical absorption edge of ferroelectric microcrystals. The photoluminescent emission intensities of the characteristic transitions of Sm3+ exhibited significant enhancement after electric polarization, with a maximum modulation ratio exceeding 200 %. The underlying luminescence modulation mechanism is discussed. This work proposed a novel strategy for fabrication of flexible composite thick films with coupling behavior between luminescent and ferroelectric properties.

Colourful 3-amino-1,8-naphthalimide alkyl-substituted fluorescent derivatives

The optical properties of four 3-amino-1,8-naphthalimide derivatives differing in the degree of substitution at the amino functionality were synthesised and studied by UV–visible absorbance and fluorescence spectroscopy in 1:1 (v/v) methanol/water and methanol. The compounds were structurally characterized by NMR, IR and HRMS. The charge transfer absorbance band was observed to shift to longer wavelength with increasing ethyl substitution. The emission band was also observed to shift to longer wavelengths with a decrease in the emission intensity with increasing ethyl substitution due to the peri effect. Irradiation of dye methanol solutions and in the solid state with a 365 nm UV lamp reveals distinct emission colours for each compound. Significantly larger Stokes shifts are observed in methanol than in mixed aqueous methanol. Quantum chemical calculations at the B3LYP/TZVP level of theory provided insight into the optimized ground state geometry, frontier molecular orbitals levels and solute-solvent dynamics revealing a stronger hydrogen bond between the 3-amino-1,8-naphthalimides and methanol in the lowest S1 excited state. The dyes were tested as fluorescent stains in MCF-7 cancer cells and observed to emit green emission in various organelles.

Low-emission hydrogen production from gasification of Australian coals – Process simulation and technoeconomic assessment

Although renewable energy-based technologies such as water electrolysis and biomass gasification for hydrogen production are cleaner than fossil energy-based routes, there are still prevailing challenges associated with the high cost and operational challenges in the scale-up of those technologies in the short term. Considering the abundance of coal as a current primary source of energy in Australia, the use of coal to produce hydrogen is not only in line with Australia's resource endowment but is also expected to become a supplement to the other hydrogen production pathways during the global energy transition period. This paper presents a comprehensive techno-economic assessment of low-emission hydrogen production from Australian coal gasification integrated with carbon capture and storage (CCS). The study explores four cases of hydrogen production, comparing Australian brown coal (Victorian brown coal) and black coal (Queensland black coal) gasification. Variations in gasifiers, gasification agents, and associated operating conditions contribute to differences in energy efficiency, costs, and CO2 emissions among the cases. The findings reveal a levelized cost of hydrogen from coal gasification ranging between A$4.12–4.90 per kg of hydrogen. Notably, entrained flow gasification of Victorian brown coal in a mixture of oxygen and steam environment demonstrates advantages under the current market conditions. However, less mature technologies like dual fluidized bed gasifiers could emerge as viable alternatives if deployed on a commercial scale. The study also addresses direct carbon emissions from the process, indicating a CO2 emission intensity range of 16.3–20.9 kg CO2/kg H2 without CCS and 0.1–1.1 kg CO2/kg H2 with CCS for the four cases. These insights contribute valuable information for decision-making in the pursuit of sustainable and economically feasible hydrogen production methods during the ongoing energy transition.