Abstract This review summarizes the corrosion inhibition of steel materials in acidic media. Numerous corrosion inhibitors for steels in acidic solutions are presented. The emphasis is on HCl solutions, lower-grade steels, and elevated temperatures. This review is also devoted to corrosion inhibitor formulation design – mixtures of corrosion inhibitors with (mainly) surfactants, solvents, and intensifiers to improve the effectiveness of individual compounds at elevated temperatures. The information presented in this review is useful for diverse industrial fields, primarily for the well acidizing procedure, and secondly for other applications where corrosion inhibitors for steel materials are needed.
Summary Cement is used globally in construction materials for nearly all civil infrastructure systems supporting improved quality of life, and there is currently no substitute that can meet its functional capacity. The magnitude of cement production leads to more than 7% of annual anthropogenic greenhouse gas (GHG) emissions, resulting from both energy use and chemical reactions, which imposes a notable barrier to reach net zero emissions by 2050. This barrier is exacerbated by the interconnectivity of industries responsible for cement consumption. Here, we articulate current emission reduction challenges facing industries responsible for the production and use of cement and its products, and propose a compilation of solutions that focus on mitigating emissions from cement production at various stages along its value chain. We present frameworks for design within a circular economy and for policy decisions. We anticipate that these strategies can deliver cement production with zero GHG emissions and alleviate other environmental impacts.
Polishing in jewellery manufacturing produced polishing dust containing gold particle that need to be recovered. Two methods are available, hydrometallurgical method (aqua regia) and pyrometallurgical method (direct melting). The two methods are compared from recovery, process time, economic, and safety aspects. Recovery of direct melting show higher result of 99.97 compared to 97.08% recovery of aqua regia from fire assay sample. Direct melting is shorter in process time compared to aqua regia due to simpler steps involved, thus reducing production time, minimizing labour requirement, and human error. Inert slag waste produced by direct melting also safer and cheaper for handling compared to acidic waste produced by aqua regia. From safety aspect, direct melting with appropriate Air Pollution Control System (APCS) has manageable thermal risk compared to toxic gas and corrosive risk of aqua regia. From these aspects, jewellery industry can be recommended to transition to direct melting compared to aqua regia method for gold recovery from polishing dust.
ExoKuiper belts around young A-type stars often host CO gas, whose origin is still unclear. The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) includes 6 of these gas-bearing belts, to characterise their dust and gas distributions and investigate the gas origin. As part of ARKS, we observed the gas-rich system HD121617 and discovered an arc of enhanced dust density. In this paper, we analyse in detail the dust and gas distributions and the gas kinematics of this system. We extracted radial and azimuthal profiles of the dust (in the millimetre and near-infrared) and gas emission ($^{12}$CO and $^{13}$CO) from reconstructed images. To constrain the morphology of the arc, we fitted an asymmetric model to the dust emission. To characterise the gas kinematics, we fitted a Keplerian model to the velocity map and extracted the azimuthal velocity profile by deprojecting the data. We find that the dust arc is narrow (1-5 au wide at a radius of 75 au), azimuthally extended, and asymmetric; the emission is more azimuthally compact in the direction of the system's rotation, and represents 13% of the total dust mass (0.2$M_\oplus$). The arc is much less pronounced or absent for small grains and gas. Finally, we find strong non-Keplerian azimuthal velocities at the inner and outer wings of the ring, as was expected due to strong pressure gradients. The dust arc resembles the asymmetries found in protoplanetary discs, often interpreted as the result of dust trapping in vortices. If the gas disc mass is high enough ($\gtrsim20M_\oplus$, requiring a primordial gas origin), both the radial confinement of the ring and the azimuthal arc may result from dust grains responding to gas drag. Alternatively, it could result from planet-disc interactions via mean motion resonances. Further studies should test these hypotheses and may provide a dynamical gas mass estimate in this CO-rich exoKuiper belt.
Volatile compounds not only contribute to the distinct flavors and aromas found in foods and beverages, but can also serve as indicators for spoilage, contamination, or the presence of potentially harmful substances. As the odor of food raw materials and products carries valuable information about their state, gas sensors play a pivotal role in ensuring food safety and quality at various stages of its production and distribution. Among gas detection devices that are widely used in the food industry, metal oxide semiconductor (MOS) gas sensors are of the greatest importance. Ongoing research and development efforts have led to significant improvements in their performance, rendering them immensely useful tools for monitoring and ensuring food product quality; however, aspects related to their limited selectivity still remain a challenge. This review explores various strategies and technologies that have been employed to enhance the selectivity of MOS gas sensors, encompassing the innovative sensor designs, integration of advanced materials, and improvement of measurement methodology and pattern recognize algorithms. The discussed advances in MOS gas sensors, such as reducing cross-sensitivity to interfering gases, improving detection limits, and providing more accurate assessment of volatile organic compounds (VOCs) could lead to further expansion of their applications in a variety of areas, including food processing and storage, ultimately benefiting both industry and consumers.
Abstract Cement is widely produced and used. Cement production consumes a significant amount of energy and natural resources, and it accounts for approximately 7% of man-made greenhouse gas (GHG) emissions in CO2-equivalents globally. The cement industry is continually conducting research and development into energy conserving and low-carbon technologies to reduce CO2 emissions. Furthermore, the industry will be at the heart of a carbon recycling system along cement and concrete value chain using newly developed mineral carbon capture and utilization (MCC&U) technology to reduce CO2 emissions substantially during clinker and/or cement production. This paper provides fundamental calculations for the determination of CO2 emissions from the MCC&U technology in the cement industry, which will contribute to the calculation of GHG inventories and life cycle assessments of the system. Demonstration experiments were conducted to develop an accounting formula and clearly determine CO2 emissions for recarbonate utilization as a cement raw material.
Electrification is a highly effective decarbonization and environmental incentive strategy for the chemical industry. Nevertheless, it may lead to downstream challenges in the process. This study analyzes the consequences of electrifying compressors within the steam cracker (SC) condensate system, focusing on the reduction in greenhouse gas (GHG) emissions and energy consumption without compromising the process’s energy efficiency. The aim is to study the impact that the reduction in steam expanded by turbines has on boiler feedwater (BFW) temperature and, subsequently, the behavior it triggers in fuel gas (FG) consumption and carbon dioxide (CO<sub>2</sub>) emissions in furnaces. It was concluded that condensate imports from the Energies and Utilities Plant (E&U) would increase by a factor of four, with approximately 60% of the imported condensate being cold condensate. The study revealed a mitigation of CO<sub>2</sub> emissions, resulting in a 1.3% reduction and a reduction in FG consumption of 1.8% preventing an increase in site energy consumption by 795.4 kW in furnaces. Condenser optimization reduces CO<sub>2</sub> emissions by 60%. Energy integration with quench water resulted in heat saving of 1824 kW in hot utility consumption and generating annual savings of EUR 2.3 M. The global carbon dioxide balance can achieve up to a 25% reduction.
Ehsan Amini, Kamran Ahmadi, Alimorad Rashidi
et al.
Abstract Boehmite nanoparticles and NaY nanozeolite were synthesized by co-precipitation and hydrothermal methods, respectively, and characterized by XRD, FT-IR, TG-DTA, BET, and SEM techniques. XRD and BET analyses demonstrated the formation of boehmite nanoparticles with a surface area of 350 m2/g and high crystallinity NaY nanozeolite with a surface area of 957 m2/g. In order to evaluate the effect of the content of the mesoporous boehmite nanoparticles on the catalytic performance of the Residue Fluid Catalytic Cracking (RFCC) catalyst, alumina active matrix-based and silica inactive matrix-based catalysts were prepared. Results actually demonstrated that the acidity of the zeolite composition improved with the addition of boehmite nanoparticles. On the other hand, in equal zeolite content, the alumina active matrix-based catalyst possessed higher acidity (NC30B20, 3.44 mmol NH3/g catalyst) than the silica inactive matrix-based catalyst (NC30B0, 2.31 mmol NH3/g catalyst). Microactivity tests (MAT) demonstrated that, with equal zeolite content, active matrix-based catalysts exhibited higher catalytic performance than inactive matrix-based catalyst. Furthermore, the active matrix-based catalyst (NC30B20) with a surface area of 370 m2/g showed the optimum catalytic performance in the RFCC process. The synthesized NC30B20 catalyst with 20 wt% mesoporous boehmite nanoparticles as an active matrix and 30 wt% zeolite nanoparticles balanced with silica had the highest gasoline yield (42 wt%) and gasoline selectivity (65.1 wt%). The catalytic performance test results showed that in equal MAT conversion (almost 64 wt%), the synthesized NC30B20 catalyst had higher catalytic performance than the commercial catalyst.
Rădoi Florin, Boantă Corneliu, Gherghelaș Androo Paul
et al.
The ventilation system is a key component in ensuring safe working conditions in underground mining operations, especially in coal mines such as the Lupeni Mine. This paper presents an updated analysis of the mine's ventilation network, with the primary objective of identifying existing inefficiencies and proposing technical solutions to optimize airflow throughout the underground workings. Based on topographic data, in-situ measurements, and simulations performed using specialized software, the study evaluates the main ventilation routes, pressure losses, air volume distribution across different areas, and the performance of the ventilation equipment in use. The results highlight the presence of poorly ventilated sectors, particularly in active work zones and areas prone to gas accumulation. Following the analysis, several improvements are proposed, including the reconfiguration of ventilation paths, modernization of ventilation fans, and implementation of an automated monitoring system for underground atmospheric parameters. This study contributes to enhancing worker safety, improving energy efficiency, and aligning the ventilation infrastructure with current technical and regulatory standards in the mining industry.
Adsorption phosphorus removal is a sustainable treatment technology with dual functions of waste recycling and environmental protection. In this study, biochar and zeolite were modified by mechanical ball milling and compounded to study the adsorption effect of composite materials on phosphorus in water. The experimental materials were measured by scanning electron microscopy, Fourier transform infrared spectroscopy and specific surface area and pore size analyzer to reveal the phosphorus removal mechanism of the composite material. The results showed that the best preparation conditions for phosphorus adsorption efficiency of modified zeolite-peanut shell biochar and modified zeolite-corn straw biochar were ball milled at 600r/min for 4 h. When the initial concentration of phosphorus was 40 mg/L, the removal rate of phosphorus by modified zeolite-corn straw biochar was 76.74 %, and the removal rate of phosphorus by modified zeolite-peanut shell biochar was 77.63 %. In the environment of low concentration phosphorus solution, when the input amount of the two composites was 0.15 g, the removal rate of phosphorus reached 84.72 %. It can be seen that the modified zeolite-biochar composite adsorption material has good adsorption performance for phosphorus in water, which provides a broad application prospect for the study of phosphorus adsorption materials.
Objective and SignificanceAs the coal mining depth increases, coal mining faces increasingly prominent challenges including coal and gas outbursts, rock bursts, and compound dynamic disasters. Deepening the understanding of disaster-causing mechanisms and developing diversified prevention and control technologies are significant for the safe production of coal mines. Employing the key technologies for coalbed methane (CBM) production to control gas-related dynamic disasters is an inevitable course for the safe production of coal mines. However, large-scale, suitable technology systems are yet to be developed. MethodsFrom the perspective of the application of key technologies for surface CBM production, this study systematically reviews the development history and research advances in technologies including well drilling and completion for CBM production and fracturing. From the angle of coal mine safety, this study organizes the disaster-causing mechanisms and critical control technologies for gas dynamic disasters over the past 70 years. In combination with the characteristics of CBM production technologies and the demand for the prevention and control of dynamic disasters in coal mines, this study proposes some suggestions for theoretical innovation and technological breakthroughs. Results and ConclusionsIn terms of theoretical research, it is necessary to deepen the comprehensive exploration of coals and CBM and conduct fine-scale geological studies by integrating multiple approaches. Regarding control technologies, efforts should be made to further explore the control technologies for coal and gas outbursts and rock bursts, with the former including (1) outburst elimination using cavity-type tube wells+high-pressure air/liquid nitrogen/CO2 scrubbing + negative-pressure drainage and (2) multistage fracturing of L-shaped surface horizontal wells+production and the latter including (1) multistage hydraulic fracturing of roofs using L-shaped wells and (2) proppant injection-based multistage hydraulic fracturing for roofs using L-shaped wells+production. Accordingly, advanced technologies such as multistage fracturing of L-shaped wells for CBM production should be employed to conduct on-site experiments on gas dynamic disaster control. It is necessary to explore the applicability of varying prevention and control theories and technologies under different geologic conditions based on scientific research and engineering integrated engineering and projects and develop technology systems for the prevention and control of gas dynamic disasters in coal mines, thus providing robust support for the safe production of coal mines in China.
With the emergence of ChatGPT, Transformer models have significantly advanced text classification and related tasks. Decoder-only models such as Llama exhibit strong performance and flexibility, yet they suffer from inefficiency on inference due to token-by-token generation, and their effectiveness in text classification tasks heavily depends on prompt quality. Moreover, their substantial GPU resource requirements often limit widespread adoption. Thus, the question of whether smaller language models are capable of effectively handling text classification tasks emerges as a topic of significant interest. However, the selection of appropriate models and methodologies remains largely underexplored. In this paper, we conduct a comprehensive evaluation of prompt engineering and supervised fine-tuning methods for transformer-based text classification. Specifically, we focus on practical industrial scenarios, including email classification, legal document categorization, and the classification of extremely long academic texts. We examine the strengths and limitations of smaller models, with particular attention to both their performance and their efficiency in Video Random-Access Memory (VRAM) utilization, thereby providing valuable insights for the local deployment and application of compact models in industrial settings.
The acceleration of the energy transition is driven by current geopolitical conflicts and climate and environmental challenges. It is crucial for China to construct a new energy system adapting to these changing circumstances for the sustainability, security, and stability of the energy supply system. At present, fossil fuels still dominate the China’s energy demand. There are energy security issues due to lacking oil and gas resources, and new energy technologies. China will still maintain a high dependence on coal energy in short term, consequently, prompting the clean and efficient conversion of coal is vital for developing a new energy system. In this paper, the specific connotations and develop direction of the new energy system are identified, and then the development status, opportunities and challenges of the China’s coal chemical industry in the new era are presented, also the suggestions for improving the technology of clean and efficient coal conversion and the future development of coal chemical industry are put forward. The new era has endowed the new energy system with more connotations, that is the future energy system should be characterized by “safe and efficient, clean and low-carbon, diverse and synergistic, and intelligent and accessible”. In addition, the new era will put forward higher requirements for the clean and efficient development of the coal industry.Although China has made significant achievements in the clean and efficient conversion of coal, the key technologies still need some breakthroughs.Combining the systematic understanding of the relationship between the transformation and development of the coal industry and the “dual carbon” goals, and in the context of the construction of a new energy system, the promotion of clean and efficient coal conversion is of great significance for social and economic development and helping to achieve the “dual carbon” goals. The key lies in strengthening the basic research of relevant disciplines and specialties in this field, as well as the innovative development of clean and efficient coal conversion technologies.
Javier E. Gonzalez, Marcelo Ferreira, Leorando R. Colaço
et al.
In this work, we obtain Hubble constant ($H_0$) estimates by using two galaxy cluster gas mass fraction measurement samples, Type Ia supernovae luminosity distances, and the validity of the cosmic distance duality relation. Notably, the angular diameter distance (ADD) to each galaxy cluster in the samples is determined by combining its gas mass fraction measurement with galaxy clustering observations, more precisely, the $Ω_b/Ω_m$ ratio. Such a combination results in a $H_0$ estimate that is independent of a specific cosmological framework. In one of the samples, the gas fraction measurements were calculated in spherical shells at radii near $r_{\rm 2500}$ (44 data points), while in the other (103 data points) the measurements were calculated within $ r_{\rm 500}$. We find $H_0=72.7^{+6.3}_{-5.6}$ km/s/Mpc at 68\% CL for the joint analysis of these data sets. We also investigate the impact on the $H_0$ determination by exploring the precision and number of gas mass fraction data by performing a data Monte Carlo simulation. Our simulations show that future measurements could achieve a precision of up to 5\% for $H_0$.
Linn Danielsen Evjemo, Qin Zhang, Hanne-Grete Alvheim
et al.
The significant growth in the aquaculture industry over the last few decades encourages new technological and robotic solutions to help improve the efficiency and safety of production. In sea-based farming of Atlantic salmon in Norway, Unmanned Underwater Vehicles (UUVs) are already being used for inspection tasks. While new methods, systems and concepts for sub-sea operations are continuously being developed, these systems generally does not take into account how their presence might impact the fish. This abstract presents an experimental study on how underwater robotic operations at fish farms in Norway can affect farmed Atlantic salmon, and how the fish behaviour changes when exposed to the robot. The abstract provides an overview of the case study, the methods of analysis, and some preliminary results.
We obtain a generalized law of the iterated logarithm for a class of dependent processes with superdiffusive behaviour. Our results apply in particular to the Lorentz gas with infinite horizon.
The development of new energy vehicles has become a common choice for countries worldwide to reduce greenhouse gas emissions and improve the global ecological environment, with China being no exception. However, challenges, such as finding charging stations, accessing residential areas, and highway charging, have hindered the green and high-quality growth of the new energy vehicle industry. This study, set against the backdrop of China’s 2018 policy to gradually redirect local purchase subsidy funds for new energy vehicles towards supporting the construction and operation of charging infrastructure, utilizes panel data from 282 prefecture-level cities from 2016 to 2021. A difference-in-differences model is constructed to compare the impact of infrastructure development on carbon emissions before and after the policy’s implementation. The study finds that policy has a negative effect on carbon emissions, especially in the second and third year after the policy’s implementation. Even after controlling for variables such as residents’ wealth levels, population size, environmental pollution, energy consumption, and government support, the results remain significant. Heterogeneity analysis reveals that the effect of the promotion of charging infrastructure on carbon emissions is greater in southern and central parts of China.
The paper presents the results of reverse engineering including metallographic, mechanical, and engineering-technical studies of used rods of a compressor produced by the Dresser-Rand company (Siemens, Germany). The study established that the original product is made of AISI 4140 steel with a working coating based on tungsten carbide applied to a depth of 0.2 mm by the HVOF method. The paper contains the results of the development of an import-substituting technological process for producing a wear-resistant powder coating of the Ni–Cr–B–WC system applied by cold gas flame spraying on the surface of a critical unit of compressor equipment in the oil and gas industry. Microanalysis identified that the sprayed spherical WC particles are evenly distributed in the nickel bond without the formation of free cavities at the lamella boundary, retain the size identical to the original powder composition upon the high-speed collision with the substrate, and minimize the level of residual mechanical stresses in the surface layer. The study shows that the sprayed coating has a high microhardness (the bases – 700 HV0.1, WC – up to 2000 HV0.1), which ensures high wear resistance during operation of the rod in a friction pair. A comparative analysis of the tribological properties of the coatings showed that when changing the shape, particle size distribution, and percentage ratio of tungsten carbide from 20 to 70 % in the nickel matrix, the overall wear resistance of the coating equivalently increases. The authors concluded on the possibility of manufacturing an import-substituting product using the gas flame spraying technology with metallurgical powder compositions containing tungsten. The authors developed an industrial technology for applying a wear-resistant coating on the working surface of a rod made of AISI 4140 steel. The paper presents the results of the analysis of the stress state of a material with a coating produced using the developed technology in comparison with the original product. In the product obtained by the experimental technology, in the process of applying the coating and its subsequent mechanical processing, uniform residual mechanical stresses are formed that do not exceed the value of the difference in the principal mechanical stresses. The paper presents the results of the study obtained both on standard samples and on a pilot part.
Materials of engineering and construction. Mechanics of materials