Search Results (1,120)

The complex application environments of gas detection, such as in industrial process monitoring and control, atmospheric and environmental monitoring, and food safety, require real-time and online high-sensitivity gas detection, as well as the accurate identification and quantitative analysis of gas samples. Despite the progress in gas analysis and detection methods, high-precision and high-sensitivity detection requirements for target gases of multiple components in mixed gases are still challenging. Here, we demonstrate a micro-electromechanical system (MEMS) with near-infrared (NIR) spectral gas detection technology and spectral model training, which is used to improve the detection and classification of multi-component gases in food. During blind sample testing, the NIR spectral gas sensor demonstrated over 90% accuracy in identifying mixed gases, as well as achieving the classification of ethanol concentration. We envision that our design strategy of an NIR spectral gas sensor could enhance the gas detection and distinguishing ability under the conditions of background gas interference and cross-interference in multi-component detection. Full article

Avoiding atmospheric pollution with sulfur dioxide is generally achieved by its absorption from combustion gases in alkaline solutions and conversion to sulfites. Afterwards, sulfites can be transformed into neutral and environmentally safe chemicals by oxidation to sulfates. The oxidation of sulfites to sulfates can also be carried out in a cell in which the fuel will be sulfite ions. In this way, in addition to the beneficial effect of neutralizing large quantities of sulfite waste, electrical energy is also obtained. This is one of the reasons why study of the anodic oxidation of sulfite to sulfate on various electrode materials was necessary. Given the sensitivity of electrode materials in the presence of sulfur compounds, in our research we approached the study of sulfite oxidation on the Incoloy 800 anode in neutral solution (1 mol L⁻¹ Na₂SO₄). In this research, the results obtained in the study of the kinetic parameters of the anodic process as a function of the sulfite concentration (10⁻¹, 0.5, and 1 mol L⁻¹), using linear voltammetry, are presented. The appreciable values of the exchange current density (3.4, 3.0, and 2.6 A m⁻²) show that Incoloy 800 has a significant catalytic effect in the anodic oxidation of sulfite. Chronoamperometric studies have shown that the anodic oxidation of sulfite is controlled by the mass transfer of sulfite ions from the bulk solution to the electrode surface. According to the chronocoulometric diagrams, it can be appreciated that, up to anodic potentials of +1.50 V, sulfite oxidation occurs on the electrode, while at more positive potentials, the oxygen evolution reaction is the main process. Electrochemical impedance data provide evidence of a chemical reaction coupled with electron transfer, which was modeled using a Gerischer impedance. At high sulfite concentrations, the charge transfer resistance (R_ct) decreases by a factor of 10, indicating that the sulfite oxidation reaction is fast at sufficiently positive potentials. On the other hand, the passivation tendency of stainless steels upon anodic polarization gives them a high corrosion resistance, so that Incoloy 800 can be a viable option as an anode material for sulfite/oxygen (air) fuel cells. Full article

As part of improving road safety around trucks, a solution was proposed to reduce the swept path width of a moving tractor–semi-trailer. This article presents a mathematical analysis of the movement of a tractor unit with a traditional semi-trailer with fixed axles and steered wheels. A simulation analysis of both presented vehicles was carried out. The core of the algorithm controlling the steering angle of the semi-trailer wheels is presented. The influence of controlling the semi-trailer’s swivel wheels on the swept path width of a tractor–trailer with a semi-trailer equipped with swivel wheels is discussed. The assumptions for building the control algorithm are presented. The article presents the advantages of the solution used along with the control algorithm. Measurable benefits resulting from the use of the presented solution are presented, such as increasing cargo space, reducing cargo transport costs, and reducing aerodynamic resistance and fuel consumption. It is worth emphasizing that reducing fuel consumption is very important because it reduces the emission of harmful exhaust gases into the atmosphere. The swept path width is important especially in the case of vehicles moving in a limited area, for example in the parking lots of transhipment and logistics centers, between urban buildings. Vehicles admitted to traffic meet the minimum conditions imposed by homologation regulations, but reducing the swept path width allows for improving the operational properties of the tractor–semi-trailer. The use of the proposed control algorithm to control the turn of the semi-trailer’s steered wheels brings tangible benefits both in improving road safety and in reducing the emission of harmful substances into the environment. Full article

Global warming is a significant threat to the future of humankind. It is caused by greenhouse gases that accumulate in the atmosphere. CO₂ emissions are one of the main drivers of global warming, and the energy sector is one of the main contributors to CO₂ emissions. Recent technological advances in artificial intelligence (AI) have accelerated the adoption of AI in numerous applications to solve many problems. This study carries out a scoping review to understand the use of AI solutions to reduce CO₂ emissions in the energy sector. This paper follows the PRISMA-ScR guidelines in reporting the findings. The academic search engine Google Scholar was utilized to find papers that met the review criteria. Our research question was “How is artificial intelligence used in the energy sector to reduce CO₂ emissions?” Search phrases and inclusion criteria were decided based on this research question. In total, 186 papers from the search results were screened, and 16 papers fitting our criteria were summarized in this study. The findings indicate that AI is already used in the energy sector to reduce CO₂ emissions. Three main areas of application for AI techniques were identified. Firstly, AI models are employed to directly optimize energy generation processes by modeling these processes and determining their optimal parameters. Secondly, AI techniques are utilized for forecasting, which aids in optimizing decision-making, energy transmission, and production planning. Lastly, AI is applied to enhance energy efficiency, particularly in optimizing building performance. The use of AI shows significant promise of reducing CO₂ emissions in the energy sector. Full article

Climate change is a contemporary global challenge that requires comprehensive solutions to mitigate its adverse effects. All human activities contribute to climate change, mainly through atmospheric emissions of greenhouse gases (GHGs), such as nitrous oxide (N₂O), carbon dioxide (CO₂), and methane (CH₄). While most of these emissions are primarily due to fossil fuel use, agriculture and livestock production also contribute to a significant share of approximately 12% of global emissions. Most processes that are implemented within an animal husbandry unit are associated with greenhouse gas emissions, including manure management. This review explores the interconnection between climate change and manure management practices, highlighting the potential for sustainable approaches to mitigating GHG emissions. The key strategies for manure management, such as anaerobic digestion, nutrient management, composting, manure separation and treatment, and improved storage and handling, are discussed, as they are implemented in different livestock production systems (ruminants, poultry, and pigs). Despite the technological progress, there is still a place for further improving manure management approaches, especially in non-ruminant species leading to a higher mitigation potential and a reduction in greenhouse gases emissions. Moreover, policy support and incentives for sustainable practices are crucial for widespread adoption. Full article

This paper discusses the process of high-velocity oxygen fuel (HVOF) spraying with modeling of the gas flow parameters and behavior of WC-Co-Cr powder particles of different fractions (up to 20 µm, 21–35 μm and 36–45 μm). It was found that the temperature of the gas stream reaches a maximum of about 2700 °C, after which it gradually decreases, and the pressure in the combustion chamber (before the exit of gases through the nozzle) reaches maximum values, exceeding 400,000 Pa, and the pressure at the exit of the nozzle stabilizes at about 100,000 Pa, which corresponds to the standard atmospheric pressure. The gas velocity increases to 1300–1400 m/s and then decreases to 400 m/s at a distance of about 150 mm. It was determined that powder particles of the 21–35 µm fraction provide more stable parameters of velocity and temperature. Small particles (up to 20 µm) lose velocity and temperature faster as they advance, which deteriorates the coating quality, which was also experimentally confirmed. All results obtained from the HVOF process modeling fully align with the data from experimental studies. Full article

The development of materials with high adsorption capacity for capturing CO₂ from industrial exhaust gases has proceeded rapidly in recent years. Li₄SiO₄ has attracted attention due to its low cost, high capture capacity, and good cycling stability for direct high-temperature CO₂ capture. Thus far, the CO₂ adsorption mechanism of Li₄SiO₄ is poorly understood, and detailed phase transformations during the CO₂ adsorption process are missing. Here, aided by in situ X-ray diffraction and in situ Raman spectroscopy, we find that Li₄SiO₄ reacts with CO₂ to form Li₂SiO₃ and Li₂CO₃ in CO₂ atmosphere at 973 K, with no detectable involvement of crystalline Li₂O during the adsorption process. Moreover, we observe a formation of stepped structures in the Li₄SiO₄ surface after CO₂ adsorption by scanning electron microscopy. To illustrate the formation of stepped structures, we propose a modified double-shell mechanism, suggesting a possible two-dimensional nucleation and growth of Li₂CO₃. This work provides a deeper understanding of the CO₂ adsorption mechanism and paves a way for further optimization of Li₄SiO₄-based adsorbents. Full article

In this work, a series of Ba_xMn_0.7Cu_0.3O₃ samples (x: 1, 0.9, 0.8, and 0.7, BxMC) was synthesized, characterized, and used as catalysts for CO oxidation reaction. All formulations were active for CO oxidation in the tested conditions. A correlation between the electrical conductivity, obtained by impedance spectroscopy, and the reducibility of the samples, obtained by H₂-TPR, was observed. The Ba_0.8Mn_0.7Cu_0.3O₃ composition (B0.8MC) showed the best catalytic performance (comparable to that of the 1% Pt/Al₂O₃ reference sample) during tests conducted under conditions similar to those found in the exhaust gases of current gasoline engines. The characterization data suggest the simultaneous presence of a high Mn(IV)/Mn(III) surface ratio, oxygen vacancies, and reduced copper species, these two latter being key properties for ensuring a high CO conversion percentage as both are active sites for CO oxidation. The reaction temperature and the reactant atmosphere composition seem to be the most important factors for achieving a good catalytic performance, as they strongly determine the location and stability of the reduced copper species. Full article

A major challenge in accidental or unregulated releases is the ability to identify the pollutant source, especially if the location is in a large industrial area. Usually in such cases, only a few sensors provide non-zero signal. A crucial issue is therefore the ability to use a small number of sensors in order to identify the source location and rate of emission. The general problem of characterizing source parameters based on real-time sensors is known to be a difficult task. As with many inverse problems, one of the main obstacles for an accurate estimation is the non-uniqueness of the solution, induced by the lack of sufficient information. In this study, an efficient method is proposed that aims to provide a quantitative estimation of the source of hazardous gases or breathable aerosols. The proposed solution is composed of two parts. First, the physics of the atmospheric dispersion is utilized by a well-established Lagrangian stochastic model propagated backward in time. Then, a new algorithm is formulated for the prediction of the spacial expected uncertainty reduction gained by the optimal placement of an additional sensor. These two parts together are used to construct an adaptive decision support system for the dynamical deployment of detectors, allowing for an efficient characterization of the emitting source. This method has been tested for several scenarios and is shown to significantly reduce the uncertainty that stems from the insufficient information. Full article

As the applications of unmanned aerial vehicles (UAV) expand, reliable communication between UAVs and ground control stations is crucial for successful missions. However, adverse weather conditions caused by atmospheric gases, clouds, fog, rain, and turbulence pose challenges by degrading communication signals. Although, some recent studies have explored the nature of signal attenuation caused by atmospheric weather variations, studies that compare the attenuation from various weather conditions and analyze the effect on available bandwidth are missing. This work aimed to address this research gap by thoroughly investigating the impact of atmospheric weather conditions on the bandwidth available for UAV communications. Quantitative and qualitative performance analyses were performed for various weather conditions using metrics such as attenuation and the bit error rate of the received signals associated with different modulation schemes and frequencies, using a linearly segmented attenuation model. The results indicate that atmospheric gases and clouds/fog affect wireless signal propagation; however, the effect of rain on the propagation distances and operating frequencies considered in this study was the most severe. Based on the influence of power transmission, operating frequency, modulation schemes, distance, and adverse weather conditions on the bit error rate and bandwidth suboptimization, we propose an algorithm to select the maximum operating frequency for reliable UAV link operation. Full article

The Integrated Carbon Observation System (ICOS) is the reference Research Infrastructure (RI) for the observation of greenhouse gases (GHGs) across Europe, providing standardised, long-term and high-precision measurements of the most relevant species (CO₂, CH₄, CO, etc.). The ICOS Atmosphere network currently extends throughout the continent, although the density of stations in the Mediterranean area is still low compared to Central and Northern Europe. In this context, the recently implemented class 1 continental station near Potenza in Basilicata, Italy—station code: POT—represents an important step forward in the extension of the ICOS atmosphere domain across the South, reducing the large spatial gaps existing between ICOS sites within the Mediterranean basin. Herein, we provide a description of the new ICOS POT station and the site where it operates, focusing mostly on the technical setup of the sampling system which plays a key role in GHG measurements. With a strong technical connotation, the present paper aims to be beneficial for the ICOS atmosphere community and those stations that intend to join the network in the future, providing an accurate description of the station at the level of single components. Moreover, a brief overview of the peculiarities of the site and the scientific perspectives to be pursued, together with very preliminary data collected at the new ICOS station, are presented. Preliminary data collected during a short campaign are compared with STILT (Stochastic Time-Inverted Lagrangian Transport) model results as a first test of the measurements and to provide a first insight of the specific Potenza situation in terms of GHG concentrations. Full article

Multi-axis differential absorption spectroscopy (MAX-DOAS) has become an important tool for detecting trace gases in optical remote sensing. At present, the temporal resolution of the system using the traditional motor-rotated elevation telescope is extremely low. We focus on studying the atmospheric radiation transmission of fast synchronous MAX-DOAS (FS MAX-DOAS), which has greatly improved the temporal resolution on the ground and on mobile platforms and the influence of related parameters on the atmospheric mass factor (AMF), which is used to guide the design and experiments of the new system. The optimal elevation angle combination, the spectral resolution, and the specific effects of relevant parameters on the AMF during profile inversion by the new system were analyzed, and the feasibility of the new system for mobile MAX-DOAS was evaluated. The inversion results of the measured spectra collected by the system show that FS MAX-DOAS can meet the requirements of both ground and mobile platform observation scenarios. The results of our sensitivity study are of great significance for guiding experiments. Full article

Climate change has been significantly affecting human activities due to the accumulation of greenhouse gases, such as carbon dioxide. Biofixation of carbon dioxide (CO₂) has been investigated to reduce the atmospheric CO₂ level and slow the rapid increase in the global temperature. Carbon capture and utilization (CCU) can be performed by either physio-chemical or biological methods. The latter takes place in ambient temperature and mild conditions, such that there is no need for high pressure and high energy consumption nor hazardous chemicals. Biofixation by microalgae has been utilized to capture CO₂ and the microalgae biomass collected after the process can be further utilized in renewable biofuel generation. On the other hand, microbial enzymes, such as carbonic anhydrase (CA), have been investigated to speed up the whole biofixation process by increasing the conversion rate of CO₂ into bicarbonate (HCO₃⁻) in a culture medium and the latter can be readily used by microalgae to increase CO₂ removal. In this study, in the presence of 20% CO₂ (v/v) gas in air and 5 mL CA enzyme extract (0.5 mg mL⁻¹ protein), we can significantly increase the biofixation rate using marine green microalgae, Tetraselmis sp. Results showed that the biofixation rate can be increased from 0.64 g L⁻¹ day⁻¹ (no CA and at 0.04% CO₂) to 4.26 g L⁻¹ day⁻¹. The effects of different experimental conditions such as pH, nutrient levels and working CO₂ concentration levels on Tetraselmis sp. growth and CO₂ biofixation (CO₂ removal) rate have been investigated. This study demonstrates a new alternative approach for effective carbon capture and utilization (CCU) using microalgae which can be applied to achieve the goal of carbon neutrality. Full article

In recent years, the environmental evaluation of biorefineries has become critical for ensuring sustainable practices in bio-based production systems. This study focuses on the application of the Waste Reduction (WAR) Algorithm to assess the environmental impacts of an Extractive-based Creole-Antillean Avocado Biorefinery located in Northern Colombia, aimed at producing bio-oil, chlorophyll, and biopesticide from avocado pulp, peel, and seed, respectively. The environmental impacts were evaluated using the WAR algorithm, which quantifies the potential environmental impacts (PEI) of different process streams. The following four scenarios were developed: (1) considering only waste, (2) including waste and products, (3) including waste and energy sources, and (4) incorporating waste, products, and energy consumption. This study analyzed global impacts focusing on atmospheric and toxicological categories, with a detailed assessment of the most critical scenario. The results indicated that Scenario 4 had the highest PEI, particularly in the atmospheric and toxicological categories, driven by emissions of volatile organic compounds (VOCs), greenhouse gases (GHGs), and the presence of heavy metals. However, the avocado biorefinery process demonstrated a net reduction in overall environmental impacts, with negative PEI generation rates across all scenarios, suggesting that the biorefinery transforms high-impact substances into products with lower global impact potential. Energy consumption emerged as a significant contributor to environmental impacts, particularly in acidification potential (AP) and Atmospheric Toxicity Potential (ATP). Using natural gas as an energy source had a relatively lower environmental impact compared to coal and liquid fuels, emphasizing the need to optimize energy use in biorefinery design to improve environmental performance. Full article

Material characterization and investigation are the basis for improving the performance of electrochemical devices. However, many compounds with electrochemical applications are sensitive to atmospheric gases and moisture; therefore, even their characterization should be performed in a controlled atmosphere. In some cases, it is impossible to execute such investigations in a glove box, and, therefore, in the present work, an air-tight 3D printed cell was developed that preserves samples in a controlled atmosphere while allowing spectroscopic measurements in reflectance geometry. Equipped with a cheap 1 mm thick CaF₂ optical window or a more expensive 0.5 mm thick ZnS window, the cell was used for both optical photothermal infrared and Raman spectroscopy measures; imaging of the samples was also possible. The far-infrared range reflectance measurements were performed with a cell equipped with a diamond window. Full article