Large Emission Research Articles

Near-infrared fluorescent probe with large Stokes shift and long emission wavelength for rapid diagnosis of lung cancer via aerosol inhalation delivery

Near-infrared fluorescent probe with large Stokes shift and long emission wavelength for rapid diagnosis of lung cancer via aerosol inhalation delivery

SOFIA/HAWC+ Far-infrared Polarimetric Large Area CMZ Exploration Survey. II. Detection of a Magnetized Dust Ring in the Galactic Center

We present the detection of a magnetized dust ring (M0.8–0.2) in the central molecular zone (CMZ) of the Galactic center. The results presented in this paper utilize the first data release of the Far-Infrared Polarimetric Large Area CMZ Emission (FIREPLACE) survey (i.e., Paper I of this series). The FIREPLACE survey is a 214 μm polarimetric survey of the Galactic center using the SOFIA/HAWC+ telescope. The M0.8–0.2 ring is a region of gas and dust that has a circular morphology with a central depression. The dust polarization in the M0.8–0.2 ring implies a curved magnetic field that traces the ring-like structure of the cloud. We posit an interpretation in which an expanding shell compresses and concentrates the ambient gas and magnetic field. We argue that this compression results in strengthening of the magnetic field, as we infer from the observations toward the interior of the ring.

Wavelength-tunable photoluminescence of CsPbBr3 microcrystal via in situ halogen doping

Lead halide perovskite semiconductors have received significant attention in recent years as promising candidates for optoelectronic applications. Their controllable bandgap in nanostructures (nanocrystals, nanowires) has been widely and successfully investigated. Intentionally manipulating the atomic behavior with dopants in their macroscopic structure with high quality and stability is still challenging. We studied the crystal structure and photoluminescence (PL) behavior of the anion (Cl) doped CsPbBr3 microcrystals. The doped microcrystal with a low doping concentration has shown a large wavelength-tunable PL emission from 535 nm to 457 nm. Two separate emission peaks (blue and green) are carefully studied in the excitation power dependent PL spectra. The doping and excitation endow the perovskite microcrystal adjustable PL emission band and peak intensities, which may serve as a new degree of manipulation freedom in the color-tunable display and functional optoelectronics.

Large greenhouse gases emissions from lakes in Inner Mongolia, China

Lakes are important component of the regional carbon cycle and a significant sources of greenhouse gases (GHGs) to the atmosphere. However, the regional variations in carbon dioxide (CO2) and methane (CH4) emissions, as well as the factors regulating these emissions are poorly constrained. To investigate the regional GHG emission from lakes and their potential influencing factors, we conducted field measurements in 13 lakes in Inner Mongolia from July to August 2020. We found that the studied lakes were predominantly sources of atmosphere CO2 and CH4. The CO2 partial pressure (pCO2) exhibited supersaturation in 80 % of samplings, but all samplings of CH4 partial pressure (pCH4) showed supersaturation. Moreover, the average pCH4 is 40 times greater than that in the atmosphere. The lakes emitted substantial amounts CO2 and CH4 with average values of 25.8 ± 4.9 mmol m−2 d−1 and 2.1 ± 0.3 mmol m−2 d−1, respectively. At the regional scale, the dynamics of pCO2 and pCH4 are regulated by combination of various environmental factors. CO2 emissions from studied lakes decreased with the catchment net primary productivity (NPP), normalized difference vegetation index (NDVI), and nighttime lights which is indicative of urbanization. Conversely, CH4 fluxes increased with NPP, NDVI, and nighttime lights. We conclude that terrestrial carbon-cycling related variables and human activities significantly affect CO2 and CH4 emissions from lakes by transporting different nutrients, but they show opposite trends. Our results also exhibited that the freshwater lakes are the main contributors of CH4, while saline lakes are the main contributors of CO2. We suggest that increased human activity leads to changes in terrestrial carbon-cycle related processes which affects lake carbon emissions by altering the amount of nutrients input to the lakes.

The origin of large emission line widths in massive galaxies at redshifts z ∼ 3–4

The origin of large emission line widths in massive galaxies at redshifts <i>z</i> ∼ 3–4

Graphene Derived from Municipal Solid Waste.

Landfilling is long the most common method of disposal for municipal solid waste (MSW). However, many countries seek to implement different methods of MSW treatment due to the high global warming potential associated with landfilling. Other methods such as recycling and incineration are either limited to only a fraction of generated MSW or still produce large greenhouse gas emissions, thereby providing an unsustainable disposal method. Here, the production of graphene from treated MSW is reported that including treated wood waste, using flash Joule heating. Results indicated a 71%-83% reduction in global warming potential compared to traditional disposal methods at a net cost of -$282 of MSW, presuming the graphene is sold at just 5% of its current market value to offset the cost of the flash Joule heating process.

Directional thermal emission and display using pixelated non-imaging micro-optics

Thermal radiation is intrinsically broadband, incoherent and non-directional. The ability to beam thermal energy preferentially in one direction is not only of fundamental importance, but it will enable high radiative efficiency critical for many thermal sensing, imaging, and energy devices. Over the years, different photonic materials and structures have been designed utilizing resonant and propagating modes to generate directional thermal emission. However, such thermal emission is narrowband and polarised, leading to limited thermal transfer efficiency. Here we experimentally demonstrate ultrabroadband polarisation-independent directional control of thermal radiation with a pixelated directional micro-emitter. Our compact pixelated directional micro-emitter facilitates tunable angular control of thermal radiation through non-imaging optical principles, producing a large emissivity contrast at different view angles. Using this platform, we further create a pixelated infrared display, where information is only observable at certain directions. Our pixelated non-imaging micro-optics approach can enable efficient radiative cooling, infrared spectroscopy, thermophotovoltaics, and thermal camouflaging.

Design of Fiber Laser Based on Erbium-ion

Erbium ions (Er3+) exhibit good characteristics of fiber lasers in the 1500-1550 nm band, including three-level systems, high tilt efficiency, and large emission cross sections. This article focuses on studying the spectral characteristics of erbium ions, simulating the power propagation equation of erbium-doped ion fiber lasers, and calculating the pump power threshold and output power. The findings of the simulation indicate that the laser begins to produce 10 W of pump optical power. The laser power hits 34.38 W and the oblique power is determined to be 38.20% as soon as the pump power exceeds 100 W. Experimental results show that when pump light propagates forward, the forward propagation power of the pump light will weaken, the forward propagation power of the signal light will increase, the reverse propagation of the signal light will weaken and the reverse propagation of the pump light will Transmission will also weaken, with directional transmission remaining largely unchanged. This study carried out numerical simulations on the experimental parameters of the fiber laser doped with Er3+and finally obtained the output power of pump light and signal light under these conditions, providing better data support for the preparation of 1500-1550 nm fiber laser doped with erbium ion.

Taking stock of carbon dioxide removal policy in emerging economies: developments in Brazil, China, and India

ABSTRACT Deliberately removing carbon dioxide from the atmosphere is an important element of bringing mitigation pathways in line with the climate goals of the Paris Agreement. To reach global net-zero CO2 emissions and limit global warming to 1.5°C with no or limited overshoot, global mitigation pathways assessed by IPCC’s Sixth Assessment Report require some world regions to achieve net-negative CO2 emissions with large-scale carbon dioxide removal (CDR) deployment. This raises important questions about the availability and feasibility of CDR deployment in different societal and political contexts. This paper therefore combines an analysis of CDR deployment in a sample of scenarios from the IPCC AR6 database with a bottom-up analysis of the state of CDR governance and policy in countries considered key in scaling up CDR capacity and not yet covered by existing research. In particular, the paper focuses on Brazil, China, and India as important emerging economies and large emitters. We highlight the expected use of CDR methods in those regions in scenarios and systematically assess and compare the level of CDR regulation and innovation across these countries. This comparative perspective has the potential to broaden the understanding of existing and emerging CDR policies and politics. The synthesis of the case studies provides three key contributions to existing literature: First, we explore the state of CDR governance and policymaking in key emerging economies. As in OECD countries, there is a notable lack of CDR regulation and innovation to enable the scale of CDR required in the short- and medium term. Second, we identify that repurposing policies is a key type of emerging CDR policymaking in these countries targeting CDR methods in the land use, land use change and forestry (LULUCF) sector. We find that the repurposing efforts strengthen the level of regulation and innovation for this group of methods. Third, we explore three building blocks (regional differentiation, delay of upscaling, sustainability thresholds) of plausible CDR deployment narratives that could help bridge integrated assessment models and comparative case studies in future research.

Defect Engineering for SnO2 Improves NO2 Gas Sensitivity by Plasma Spraying.

Large emissions of nitrogen dioxide (NO2) pose a significant threat to human health, Monitoring its content and implementing timely measures are crucial. Utilizing oxide semiconductors, such as tin dioxide (SnO2), has proven to be an effective way to detect and analyze NO2. The design and preparation of sensing materials with high sensitivity and excellent selectivity is the key to improve the detection efficiency. SnO2 nanopowders with small and uniform particle size, large specific surface area, adjustable defect content, and no impurities were prepared by a new plasma spraying method. The SnO2 nanopowders exhibit outstanding performance in detecting NO2 at a low temperature of 100 °C, the response to 5 ppm of NO2 reaches 48, and the material demonstrates rapid response and recovery times, coupled with excellent selectivity. The exceptional gas-sensitive properties can be attributed to the superior morphology and structure of SnO2. It provides more reaction sites for gas sensitive reactions, fast electron transport, a large number of charge carriers, and improved adsorption of the material to the target gas. This study provides valuable insights into nanomaterial preparation and the enhancement of gas-sensitive properties for SnO2.

Experimental study of heat pipes for battery cooling technology in EVs

Abstract The modern world is moving towards electric vehicles (EV) due to the increment in greenhouse gas (GHG) emissions, global warming, and the lack of fossil fuels. EVs can overcome these issues by using batteries instead of fuel. But increasing and maintaining the batteries is a major challenge in EVs because of the large heat emissions from the batteries. In order to overcome these issues and increase the performance of the batteries, a heat pipe (HP) is attached to the passive cooling system. This study aims to improve the performance of batteries and the thermal conductivity of HP with a combination of refrigerant and nanofluid (nanorefrigerant) as working fluids. Copper HP with R-134a or SWCNT is selected for this study. The thermal resistance and thermal conductivity of HP with R-134a and SWCNT were observed for several heat conditions. From the study, it was well observed that changing the working fluid inside the HP affects the thermal performance and the cooling capacity of batteries. Fixing an HP to a battery would decrease the battery’s temperature effectively. Furthermore, increasing the heat power in an evaporator section decreases the thermal resistance and enhances thermal conductivity with the shortest time limit because of Brownian motion.

Can Australia become APAC’s CCS hub of choice?

Carbon capture and storage (CCS) is critical in Australia for future production of lower-carbon natural gas for domestic use and international export. There may also be targeted applications in other sectors, such as electricity, industrial heat generation and manufacturing, but only a small portion of the country’s carbon dioxide (CO2) emissions are likely to be addressed with carbon capture. That leaves significant CO2 storage potential untapped. Wood Mackenzie’s analysis suggests that Australia’s CCS opportunity lies less in the reduction of domestic emissions, and more in enabling other countries’ net zero ambitions. This involves building hubs to transport and store CO2 at scale, using Australia’s vast geological resources. Such hubs are major capital projects and typically require billions of dollars of investment. However, supporting CO2 storage hubs with public funding may feel like a bitter policy pill to swallow, if there is not a large Australian emissions reduction number on the other side of it. So, why should Australia put its money towards this, and fast? In this paper, we will size the economic opportunity, benchmark Australia’s competitiveness with other aspiring hubs in the region and assess the amount of investment and policies required to get there.

A survey of methane point source emissions from coal mines in Shanxi province of China using AHSI on board Gaofen-5B

Abstract. Satellite-based detection of methane (CH4) point sources is crucial in identifying and mitigating anthropogenic emissions of CH4, a potent greenhouse gas. Previous studies have indicated the presence of CH4 point source emissions from coal mines in Shanxi, China, which is an important source region with large CH4 emissions, but a comprehensive survey has remained elusive. This study aims to conduct a survey of CH4 point sources over Shanxi's coal mines based on observations of the Advanced Hyperspectral Imager (AHSI) on board the Gaofen-5B satellite (GF-5B/AHSI) between 2021 and 2023. The spectral shift in centre wavelength and change in full width at half-maximum (FWHM) from the nominal design values are estimated for all spectral channels, which are used as inputs for retrieving the enhancement of the column-averaged dry-air mole fraction of CH4 (ΔXCH4) using a matched-filter-based algorithm. Our results show that the spectral calibration on GF-5B/AHSI reduced estimation biases of the emission flux rate by up to 5.0 %. We applied the flood-fill algorithm to automatically extract emission plumes from ΔXCH4 maps. We adopted the integrated mass enhancement (IME) model to estimate the emission flux rate values from each CH4 point source. Consequently, we detected CH4 point sources in 32 coal mines with 93 plume events in Shanxi province. The estimated emission flux rate ranges from 761.78 ± 185.00 to 12 729.12 ± 4658.13 kg h−1. Our results show that wind speed is the dominant source of uncertainty contributing about 84.84 % to the total uncertainty in emission flux rate estimation. Interestingly, we found a number of false positive detections due to solar panels that are widely spread in Shanxi. This study also evaluates the accuracy of wind fields in ECMWF ERA5 reanalysis by comparing them with a ground-based meteorological station. We found a large discrepancy, especially in wind direction, suggesting that incorporating local meteorological measurements into the study CH4 point source are important to achieve high accuracy. The study demonstrates that GF-5B/AHSI possesses capabilities for monitoring large CH4 point sources over complex surface characteristics in Shanxi.

Hydrazone-linked covalent organic framework functionalized with cysteine as a fluorescence sensor and Exploration of paper chip for p-nitrophenol detection

The large use and emission of p-nitrophenol (p-NP) seriously pollute the environment and endanger human health. In this work, a hydrazone-linked fluorescent covalent organic framework (BATHz-COF) was simply synthesized at room temperature and covalently linked N-acetyl-L-cysteine (NALC) via the "thiol-ene" click reaction, where carboxyl groups were introduced to improve dispersion and fluorescence intensity. As a rapid, good selectivity and reusability fluorescence sensor, the obtained COF-NALC has been used for quantitative analysis of p-NP predicated on the internal filtering effect (IFE). Under optimal conditions, COF-NALC enabled quantitative detection of p-NP with a linear range of 5–50 μM and the detection limit was 1.46 μM. The application of COF-NALC to the detection of p-NP in river water samples was successful, and the satisfactory recoveries were 98.0%–109.3%. Furthermore, the fluorescent COF paper chips constructed by in situ growth were combined with a smartphone to build a visual platform for the quick and real-time detection of p-NP, providing an excellent illustration for the development of intelligent fluorescence sensing in environmental analysis.

Debris cover effects on energy and mass balance of Batura Glacier in the Karakoram over the past 20 years

Abstract. The influence of supraglacial debris cover on glacier mass balance in the Karakoram is noteworthy. However, understanding of how debris cover affects the seasonal and long-term variations in glacier mass balance through alterations in the glacier's energy budget is incomplete. The present study coupled an energy–mass balance model with heat conduction within debris layers on debris-covered Batura Glacier in Hunza Valley to demonstrate the influence of debris cover on glacial surface energy and mass exchanges during 2000–2020. The mass balance of Batura Glacier is estimated to be -0.262±0.561 m w.e. yr−1, with debris cover accounting for a 45 % reduction in the negative mass balance. Due to the presence of debris cover, a significant portion of incoming energy is utilized for heating debris, leading to a large energy emission to the atmosphere via thermal radiation and turbulent sensible heat. This, in turn, reduces the melt latent heat energy at the glacier surface. We found that the mass balance exhibits a pronounced arch-shaped structure along the elevation gradient, which is associated with the distribution of debris thickness and the increasing impact of debris cover on the energy budget with decreasing elevation. Through a comprehensive analysis of the energy transfer within each debris layer, we have demonstrated that the primary impact of debris cover lies in its ability to modify the energy flux reaching the surface of the glacier. Thicker debris cover results in a smaller temperature gradient within debris layers, consequently reducing energy reaching the debris–ice interface. Over the past 2 decades, Batura Glacier has exhibited a trend towards less negative mass balance, likely linked to a decrease in air temperature and reduced ablation in areas with thin or sparse debris cover.

Photobiomodulation for pain relief: Model-based estimates of effective doses of light at the neural target

IntroductionPhotobiomodulation (PBM) has been studied since the 1960s as a clinical tool. More recently, PBM has been observed to reduce compound action potential components and hypersensitivities associated with neuropathic pains. However, no definitive description of efficacious light parameters has been determined. Some reasons may be that previous meta-analyses and reviews have focused on emitter output rather than the light at the target tissue and have included data sets that are large but with notable variability (e.g., combining data from various disease etiologies, and data from PBM at various wavelengths). This fact has made it difficult to successfully define the range of effective parameters. MethodsIn this study, photon propagation software was used to estimate irradiance at a target nerve using several published data sets chosen for their narrow criteria to minimize variability. Utilizing these estimates, effective and ineffective light irradiances at the nerve of interest for wavelengths of 633 nm or 808–830 nm were examined and estimated. These estimates are focused on the amount of light required to achieve a reduction in pain or a surrogate measure via a hypothesized nerve block mechanism. ResultsAccounting for irradiance at the target nerve yielded a clear separation of PBM doses that achieved small-fiber nerve block from those that did not. For both the 633 nm group and the 808–830 group, the irradiance separation threshold followed a nonlinear path with respect to PBM application duration, where shorter durations required higher irradiances, and longer durations required lower irradiances. Using the same modeling methods, irradiance was estimated as a function of depth from a transcutaneous source (distance from skin surface) for emitter output power using small or large emitter sizes. ConclusionTaken together, the results of this study can be used to estimate effective PBM dosing schemes to achieve small-fiber inhibition for various anatomical scenarios.

Near-infrared two-photon absorption and excited state dynamics of a fluorescent diarylethene derivative

Near-infrared two-photon absorption and excited state dynamics of a fluorescent diarylethene (fDAE) derivative were investigated by time-resolved absorption and fluorescence spectroscopies. Prescreening with quantum chemical calculation predicted that a derivative with methylthienyl groups (mt-fDAE) in the closed-ring isomer has a two-photon absorption cross-section larger than 1000 GM, which was experimentally verified by Z-scan measurements and excitation power dependence in transient absorption. Comparison of transient absorption spectra under one-photon and simultaneous two-photon excitation conditions revealed that the closed-ring isomer of mt-fDAE populated into higher excited states deactivates following three pathways on a timescale of ca. 200 fs: (i) the cycloreversion reaction more efficient than that by the one-photon process, (ii) internal conversion into the S1 state, and (iii) relaxation into a lower state (S1’ state) different from the S1 state. Time-resolved fluorescence measurements demonstrated that this S1’ state is relaxed to the S1 state with the large emission probability. These findings obtained in the present work contribute to extension of the ON–OFF switching capability of fDAE to the biological window and application to super-resolution fluorescence imaging in a two-photon manner.Graphical

Global nitrous oxide emissions from livestock manure during 1890-2020: An IPCC tier 2 inventory.

Nitrous oxide (N2O) emissions from livestock manure contribute significantly to the growth of atmospheric N2O, a powerful greenhouse gas and dominant ozone-depleting substance. Here, we estimate global N2O emissions from livestock manure during 1890-2020 using the tier 2 approach of the 2019 Refinement to the 2006 IPCC Guidelines. Global N2O emissions from livestock manure increased by ~350% from 451 [368-556] Gg N year-1 in 1890 to 2042 [1677-2514] Gg N year-1 in 2020. These emissions contributed ~30% to the global anthropogenic N2O emissions in the decade 2010-2019. Cattle contributed the most (60%) to the increase, followed by poultry (19%), pigs (15%), and sheep and goats (6%). Regionally, South Asia, Africa, and Latin America dominated the growth in global emissions since the 1990s. Nationally, the largest emissions were found in India (329 Gg N year-1), followed by China (267 Gg N year-1), the United States (163 Gg N year-1), Brazil (129 Gg N year-1) and Pakistan (102 Gg N year-1) in the 2010s. We found a substantial impact of livestock productivity, specifically animal body weight and milk yield, on the emission trends. Furthermore, a large spread existed among different methodologies in estimates of global N2O emission from livestock manure, with our results 20%-25% lower than those based on the 2006 IPCC Guidelines. This study highlights the need for robust time-variant model parameterization and continuous improvement of emissions factors to enhance the precision of emission inventories. Additionally, urgent mitigation is required, as all available inventories indicate a rapid increase in global N2O emissions from livestock manure in recent decades.

Acceptor-σ-donor-σ-acceptor host material for red phosphorescent and thermally activated delayed fluorescent OLEDs

A novel bipolar host molecule di-spiro [fluorene-9,5′-quinolino [3,2,1-de] acridine-9′,9″-fluorene]-2,2″,7,7″-tetracarbonitrile (QACN) featuring an Acceptor-σ-Donor-σ-Acceptor structure was developed. Systematic investigations into its photophysical, electrochemical, and thermal properties unveiled exceptional thermal stability, a three-dimensional spatial configuration, and bipolar carrier transport capability. Employing QACN as the host material in red phosphorescent and thermally activated delayed fluorescent (TADF) organic light-emitting diodes (OLEDs) yielded a maximum external quantum efficiency of 25.3 % and 16.5 %, respectively. Compared with the commercial material TPBi (EQE = 12.0 %, λEL = 668 nm) and mCP (EQE = 14.5 %, λEL = 652 nm), the TADF OLEDs based on QACN achieved a higher EQE and a large red-shift emission (EQE = 16.5 %, λEL = 694 nm). These findings underscore the potential of QACN as an effective host material for red phosphorescent and TADF emitters and provide a new auxiliary finesse for realizing deep red and near-infrared (NIR) OLEDs.

The effect of elastic and plastic stresses on the electrical resistivity of conductive materials

The mobility sector has been responsible for large emissions of harmful greenhouse gases worldwide for years. E-mobility can contribute to a reduction of these emissions. For a faster spread and acceptance of electric vehicles, the achievable range and thus the efficiency of the individual components in the drive and charging train is essential. In addition to the battery and the electric machine, losses in the cables and bus bars are playing an increasingly important role. The cross-sectional shape, material and manufacturing technology of these conductive materials depends on the voltage and power to be transmitted and may still change in the future, especially in the field of fast charging and increased voltage.The aim of this work is to investigate the influence of the mechanical stress condition of copper, brass and aluminium materials on their electrical conductivity. The conductivity is measured by means of 4-wire measurements under defined tensile and compressive loads. The effects of elastic and plastic strains are taken into account. The findings can be used for an optimized manufacturing strategy for conductive components for future applications.