Replacement Process Research Articles

Biotic and abiotic properties mediating sediment microbial diversity and function in a river–lake continuum

A river–lake system plays an important role in water management by providing long-term and frequent water diversions. However, hydrological connectivity in the system can have a profound effect on sediment microbial communities through pH, nutrient concentrations, and benthos invertebrates. Consequently, identifying the key environmental factors and their driving mechanisms is vital for microbial adaptation strategies to extreme environments. In this study, we analyzed the significant difference in sediment bacterial and fungal community structures and diversity indices among Dongting Lake and its tributary rivers, which worked as a typical river-connected lake ecosystem. There were significant differences in biotic and abiotic environments in the sediment habitats of Dongting Lake and its tributary rivers. Random forest analysis revealed that pH and Mollusca were found to be the most important abiotic and biotic variables for predicting both bacterial and fungal community structures, respectively. The beta diversity decomposition analyses showed that the bacterial and fungal community compositional dissimilarities among different sections were dominated by species replacement processes, with more than half of the OTUs in each section being unique. Notably, both biotic and abiotic factors affected the number and the relative abundance of these bacterial and fungal unique OTUs, leading to changes in community composition. Mollusca, pH, TP, NO3-N, and NH4-N were negatively related to the relative abundance of Actinobacteria, Acidobacteria, Gemmatimonadetes, Planctomycetes, and Ascomycota, while Annelida and ORP were positively related to the relative abundance of Actinobacteria and Gemmatimonadetes. Additionally, PICRUSt analysis revealed that the functional dissimilarity among lakes and rivers was strengthened in unique species compared to all species in bacterial and fungal communities, and the changes of functional types helped to improve the habitat environment in the main Dongting Lake and promote the process of microbial growth. From our results, the role of macrozoobenthos and physicochemical characteristics in driving the sediment microbial community spatial variations became clear, which contributed to further understanding of the river–lake ecosystem.

Complementary and competitive dynamics of CO2 and N2 in CH4 – Flue gas replacement within natural gas hydrates

To mitigate global warming, the paramount imperative lies in curbing the emission of CO2. The guest replacement method is a prominent carbon-neutral technological advancement that involves injecting CO2 into natural gas hydrate layers to accomplish the dual objectives of energy production and carbon storage. In this study, the guest dynamics in the CH4 – flue gas replacement process were examined, and the impacts of the N2 concentration of the injected gas were systematically analyzed. A powder X-ray diffraction analysis of the cage-specific guest distributions after CH4 − CO2 (20 %) + N2 (80 %) replacement revealed that CH4 production increased in both the large and small cages compared to the CH4 – CO2 replacement. This enhancement was attributed to the N2 molecules participating in both cages. However, this simultaneously led to a decrease in CO2 storage potential, indicating a ‘complementary’ relationship for CH4 production and a ‘competitive’ one for CO2 storage with respect to CO2 and N2. In situ Raman spectroscopy revealed that the introduction of N2 resulted in a deceleration of CO2 storage kinetics. Guest composition measurements after replacement showed an upward trend in CH4 production and a simultaneous decline in CO2 storage as the N2 composition increased. Notably, an intriguing correlation was established between the CO2/N2 ratios for the injected gas and the replaced hydrates, exhibiting a strong alignment with a simple first-order equation. The findings not only contribute to a deeper understanding of the CH4 − CO2 + N2 replacement technique but provide practical insights for its application in real-world scenarios.

Mže a hydronyma jejího povodí ve světle etymologie

In the article the name of the West Bohemian river Mže and its tributaries are analyzed in etymological perspective. In the first plan their Slavic etymologies are analyzed. In the second plan, possibilities of their pre-Slavic origin are verified. In the case of the hydronyms Mže and Úhlava their Germanic and Celtic etymologies are discussed, while the names of other tributaries are of Slavic origin. Finally the process of replacement of the hydronymic nomenclature during changes of dominant languages is generalized in the typological perspective.

Utilization of circulating fluidized bed coal ash in autoclaved aerated concrete manufacture by mineral carbonation

Using circulating fluidized bed combustion (CFBC) ash discharged from thermal power plants, we identified factors affecting mineral carbonation to sequester CO2 and produced autoclaved aerated concrete (AAC). To use CFBC ash as a raw material for AAC, free-CaO, which causes volume expansion, was replaced through hydration and carbonation. During the raw material replacement process, carbonation behavior was confirmed through pH and temperature. A Ca(OH)2 to liquid ratio similar to a fly ash to liquid ratio of 0.25 is considered to provide sufficient diffusion distance, and the reaction rate may increase due to the rise in water temperature caused by Ca2+ leaching. Additionally, the results of XRD, XRF, TG-DTA, and SEM analyses indicate that hydration and carbonation reactions were stably achieved in the materials, suggesting that CO2 sequestration allows the materials to be used as alternative raw materials. After identifying the characteristics of the CFBC ash and the substituted material, AAC was manufactured through pressurized carbonation. The weight change rate, carbonation depth, ventilation rate, pore structure, and compressive strength of the manufactured AAC were measured. As a result, the alternative raw material exhibited higher permeability and a larger pore size range in the specimens compared to the original material, indicating easier CO2 penetration into the specimens. Consequently, this experiment suggests the potential of using the material in AAC production by providing a theoretical basis for solving volume expansion issues associated with concrete admixtures and CO2 sequestration in waste materials.

Facile strategy for uniform gold coating on silver nanowires embedded PDMS for soft electronics

Silver nanowires-embedded polydimethylsiloxane (AgNWs/PDMS) electrodes are promising components for various soft electronics, but face energy mismatch with organic semiconductors. Attempts at galvanic replacement, involving spontaneous gold (Au) formation on the electrodes, often result in non-uniform and particulate Au coatings, compromising device performance and stability. In this study, we introduce a novel approach for achieving a uniform and complete Au coating on AgNWs/PDMS electrodes by adding NaCl to the Au complex solution. This addition slows down the galvanic replacement process and prevents precipitation, enabling a uniform and complete Au coating on the AgNWs surface. Such coating significantly reduces contact resistance (RC), thereby enhancing the electrical characteristics of p-type organic transistors. Furthermore, the development of high-performance, fully soft organic transistors was achieved incorporating an organic semiconductor-elastomer blend. Additionally, reliable, mechanically stable soft glucose sensor was developed, taking advantage of the complete Au coating, which protects against oxidation during the glucose sensing process.

Hydrates production with gaseous CO2/C3H8 and CH4/C3H8 (90/10 vol%) mixtures and definition of the role of propane during CO2/CH4 replacement processes

Within the range of temperatures suitable for CO2/CH4 replacement, propane can form hydrates at widely milder conditions than those required for methane and carbon dioxide hydrates. Recent studies proved that the addition of minor quantities of propane to carbon dioxide strongly enhances replacement process, both in terms of methane recovery and carbon dioxide storage. At the same time, the capture of propane remains limited, even if the thermodynamic conditions are widely suitable for its capture. This study experimentally provided a coherent explanation of such a process. Hydrates were formed and dissociated on a lab-scale reactor with binary mixtures containing 90 vol% of CO2/CH4 and 10 vol% of C3H8; the results were compared with the phase equilibrium conditions of the pure species, obtained with the same procedure. The promoting/inhibiting effect of propane on the forming system was quantified and explained in terms of typology of hydrate structure formed and cage occupancy. Based on the results achieved in this study, the replacement mechanism, in presence of propane, was finally characterized and compared with the results obtained when replacement was carried out with the same procedure but with pure carbon dioxide and CO2/N2 mixtures.

Pore-scale deformation characteristics of hydrate-bearing sediments with gas replacement

Gas replacement method enables the simultaneous exploitation of natural gas and the realization of carbon capture, utilization, and storage (CCUS). Safe exploitation of hydrate-bearing sediments (HBS) has garnered significant attention, particularly concerning the engineering geological risks involved. Understanding deformation characteristics during shear after the replacement of HBS is crucial for safe and efficient exploitation. This study employs microfocus computer tomography and digital volume correlation (DVC) to investigate the deformation characteristics of HBS samples with varying replacement percentages. Key findings include: 1. An increase in failure strength of HBS is observed with higher replacement percentages due to improved hydrate cementation and consolidation under confining pressure. 2. DVC analysis shows that narrower radial displacement ranges are associated with increased pore compression, while wider ranges indicate greater particle repositioning. Frequent large axial displacements suggest significant pore compaction, whereas smaller axial displacements indicate particle movement and pore-filling phenomena. 3. The gas replacement process enhances the cementation structure of HBS without altering hydrate saturation, resulting in thinner shear bands and accelerated strain softening with higher replacement percentages. 4. The DVC approach effectively captures volumetric strain and deformation behaviors, offering valuable insights into sediment responses under shear. This study provides a theoretical reference for geological safety evaluation during gas replacement exploitation.

On-Device Pressure-Tunable Moving Schottky Contacts.

Contact engineering enhances electronic device performance and functions but often involves costly, inconvenient fabrication and material replacement processes. We develop an in situ, reversible, full-device-scale approach to reconfigurable 2D van der Waals contacts. Ideal p-type Schottky contacts free from surface dangling bonds and Fermi-level pinning are constructed at structurally superlubric graphite-MoS2 interfaces. Pressure control is introduced, beyond a threshold of which tunneling across the contact can be activated and amplified at higher loads. Record-high figures of merits such an ideality factor nearing 1 and an off-state current of 10-11 A were reported. The concept of on-device moving contacts is demonstrated through a wearless Schottky generator, operating with an optimized overall efficiency of 50% in converting weak, random external stimuli into electricity. The device combines generator and pressure-sensor functions, achieving a high current density of 31 A/m2 and withstanding over 120,000 cycles, making it ideal for neuromorphic computing and mechanosensing applications.

Investigation on the reaction progress of titanium and lead chloride in NaCl-KCl melt

The in-situ preparation of NaCl-KCl-TiClx molten salt electrolyte was investigated by replacement of PbCl2 and Ti in a NaCl-KCl melt at 750 ℃. The reaction progress of PbCl2(3.38 wt.%) with excess Ti was monitored in real-time by a series of electrochemical techniques such as cyclic voltammetry, square wave voltammetry, and open circuit chronopotentiometry. The thermodynamic calculation and electrochemical test results show that titanium ions are mainly generated in the form of Ti(III). The redox peak current of Pb(II) decreases rapidly and drops to below the detection limit of the electrochemical tests after 275 min. Simultaneously, the reduction peak current of Ti(III) increases rapidly from 0 to 75min, and reaches to the maximum value until 275 min. At this time, the replacement reaction has been completed, and the NaCl-KCl-TiClx(2≤x≤4) molten salt is obtained finally. Ti-Pb alloy was obtained by depositing at -1.0 V(vs. Ag/AgCl) for 30 min during the replacement process. Lead by-product of the replacement reaction was precipitated and collected. Electrolytic refining was carried out successfully using the NaCl-KCl-TiClx molten salt electrolyte prepared as described above. The results demonstrated that a stable NaCl-KCl-TiClx molten salt electrolyte can be obtained by the present method. The study provides a new thinking for the preparation of molten salt electrolyte containing titanium ions, and also provides theoretical references for the electrolytic refining of titanium and the preparation of titanium alloys by electrodeposition.

Fundamental mechanism and potential optimization methods for the overpressure phenomenon of Novec 1230 and 2-BTP

Novec 1230 (C6F12O) and 2-BTP (C3H2BrF3) created higher peak pressures (overpressure phenomenon) than with no agent in the aerosol can test of Federal Aviation Administration. Previous researches ascribed the overpressure to the fuel-like property of 2-BTP and Novec 1230. However, the fundamental cause of the overpressure phenomenon has not been fully clarified, and no solution has been proposed to improve the inhibition effect and reduce the combustion enhancement of 2-BTP and Novec 1230. For accelerating the development process of halon replacement in aircraft cargo bay, this work in-depth studied the fundamental mechanism of the overpressure phenomenon of two agents. Novec 1230 consumes O2 at low loading from the reactions of fluorine-containing groups such as C3F7 with chain branching reactions, and further produces a large amount CO and HF. Different from Novec 1230, 2-BTP does not directly consume O2, however induces a higher concentration of H radical at high loading and further promote the reaction rate of H + O2OH+O to consume large quantities of O2. In addition, the calculated pressure and the sum of the equilibrium gas composition were studied to find that 2-BTP and Novec 1230 greatly increase the total gas content, resulting in much higher pressure rise than Halon 1301. Additionally, the recommended measures of 2-BTP and Novec 1230 to improve the reduce the overpressure were proposed based on their combustion inhibition and enhancement mechanism.

Mechanical and acoustic characterization of carbon dioxide gas replacement of methane gas hydrate

CO2 replacement presents a promising approach for the extraction of natural gas hydrate, offering advantages in cleanliness and safety. In this study, CO2 replacement CH4 hydrate experiments were carried out by using the triaxial, hydrate specimens with varying replacement ratios were prepared through different methods, and triaxial tests were performed to evaluate the mechanical properties of sediments after replacement. The key findings are as follows: the shear damage behaviors of CH4, CO2, and their mixed hydrate specimens are similar. Acoustic data indicates that initial CO2 injection during replacement causes dissociation of CH4 hydrate, potentially reducing the failure strength of the reservoir. However, post-replacement hydrate specimens exhibited higher failure strength than their original counterparts. This study provides valuable insights into the mechanical stability of CH4 hydrate reservoirs during CO2 replacement process.

Radical Replacement Process for Ligated Boryl Radical-Mediated Activation of Unactivated Alkyl Chlorides for C(sp3)-C(sp3) Bond Formation.

The ligated boryl radical (LBR) has emerged as a potent tool for activating alkyl halides in radical transformations through halogen-atom transfer (XAT). However, unactivated alkyl chlorides still present an open challenge for this strategy. We herein describe a new activation mode of the LBR for the activation of unactivated alkyl chlorides to construct a C(sp3)-C(sp3) bond. Mechanistic studies reveal that the success of the protocol relies on a radical replacement process between the LBR and unactivated alkyl chloride, forming an alkyl borane intermediate as the alkyl radical precursor. Aided with the additive K3PO4, the alkyl borane then undergoes one-electron oxidation, generating an alkyl radical. The incorporation of the radical replacement activation model to activate unactivated alkyl chlorides significantly enriches LBR chemistry, which has been applied to activate alkyl iodides, alkyl bromides, and activated alkyl chlorides via XAT.

Molecular simulation of free CO2 injection on the coal containing CH4 structure and gas replacement

Understanding the replacement process of pre-adsorbed CH4 by injecting CO2 into the coal slit pores is crucial for CO2 storage and coalbed methane (CBM) extraction. We constructed the model of free CO2 injection into coal containing CH4, and used molecular simulation methods to analyze the replacement and diffusion of gas in coal as well as the coal structure deformation at different CO2 injection pressures. Results indicated that the CO2 adsorption following injection aligned with Langmuir law, and CO2 replaced CH4 more efficiently at 6 MPa injection pressure; After CO2 injection, the coal slit pore volume increased, the coal matrix aromatic structure destroyed, the coal matrix micropores volume increased and expanded radially and compressed longitudinally. Among them, the coal matrix deformation facilitated CO2 adsorption whilelittle impacting the CH4 desorption within the micropores. Higher CO2 injection pressure reduced the diffusion coefficients of adsorbed and free CH4 and CO2, but increased the CO2 adsorption depth in the coal matrix and enhanced the CO2 adsorption stability. The results provided valuable insights into the potential mechanisms of CO2-ECBM.

Streamlining marker-less allelic replacement in Streptococcus pneumoniae through a single transformation step strategy: easyJanus.

We introduce a new strategy aimed at streamlining the process for marker-less allelic replacement in Streptococcus pneumoniae, a Gram-positive bacterium and leading cause of pneumonia, meningitis, and ear infections. Our approach involves a modified genetic arrangement of the Janus cassette to facilitate self-excision during the segregation step. Since this new method reduces the amount of exogenous DNA required, it is highly amendable to the use of synthetic DNA for construction of the mutagenic construct. Our streamlined strategy, called easyJanus, offers significant time and cost savings while concurrently enhancing the efficiency of obtaining marker-less allelic replacement in S. pneumoniae.

Characterization and description of beekeeping agroecosystems in Hopelchén, Campeche, Mexico

Objective: to characterize honey bee (Apis mellifera) production systems in the municipality of Hopelchén, Campeche, Mexico. Design/methodology/approach: the sample was made up by 10% of the beekeepers in Holpechén, identified through the snowball method. A semi-structured questionnaire was designed with 94 questions grouped into five sections (general information, structure of the systems, product trade, technologies used, and decision making). The questionnaire was applied through the technique of interviewing those responsible for the 118 beekeeping production systems. The information obtained with the questionnaires was analyzed with descriptive statistics. Results: beekeeping is an important productive activity in the region of Los Chenes and La Montaña in Hopelchén, which are undergoing the process of generational replacement and are currently maintained by young adult producers who are younger than 45 years old. They own 55 hives on average per producer, which are located at a distance of 7.7 km from their households. The main technology is the use of sugar for feed, by 50% of producers, followed by the diagnosis of Varroa infestation and determination of moisture with 35 and 21.5% of beekeepers. Limitations on study/implications: the limited access to regions with beekeeping potential, as well as the lack of monitoring by outside staff, does not ease open-mindedness of beekeepers toward researchers. Findings/conclusions: the characterization of beekeeping production systems with high potential allows proposing improvement strategies to promote the development of small-scale producers.

Kualitas Pelayanan Penerbitan Sertifikat Pengganti pada Badan Pertanahan Nasional Kota Blitar

A land certificate is legal and very important proof of land ownership. Therefore, people need to look after and maintain it well. However, there are still cases where the certificate is lost, so the land owner needs to make an application to obtain a replacement certificate at the local National Land Agency. In the certificate replacement process, there are several obstacles, such as the high costs for publication in the mass media, the length of bureaucracy that the applicant must go through, the long time required to complete the service, and the large number of documents that the applicant must submit. This research aims to evaluate the quality of service in the process of issuing replacement certificates at the Blitar City National Land Agency and identify the obstacles faced in this process. This research uses qualitative methods whose results will be processed into descriptive data. The data collected includes primary data obtained from interviews and observations, as well as secondary data obtained from literature reviews. The data collection process was carried out through interviews, direct observation and documentation. The results of this research are based on a series of analysis processes from interview data, observation and documentation, showing that the quality of replacement certificate issuance services at the Blitar City National Land Agency is good. Judging from the five indicators of service quality used, namely Tangibles, Reliability, Responsiveness, Assurance and Empathy. There are obstacles faced, namely the occurrence of errors in the KKP system which is used to process all types of services, obstacles in making the oath agenda schedule which can hinder the completion of services

From MilkingBots to RoboDolphins: How AI changes human-animal relations and enables alienation towards animals

Technologies, especially disruptive technologies, have a great potential to change and reshape human-human as well as human-technology relations. This creates various ethical challenges that need to be addressed. However, technologies also have great potential to change human-animal relations. Since this aspect is underexplored in the academic debate on technologies’ impact on relations, we believe that it is important to (1), descriptively, study how new and emerging technologies impact human-animal relations, and (2), normatively, to enrich the debate with a non-anthropocentric perspective that recognizes that human-animal relations also have moral significance. Therefore, in this paper we investigate how artificial intelligence (AI) technologies and robotics impact human-animal relations, and we discuss the moral significance of these changes. AI technologies change human-animal relations due to, first, automation, and second, replacement processes. Automation processes mainly take place in the animal agriculture sector, and the replacement of biological animals with artificial AI-driven animals mainly in the context of zoos, companion animals and laboratories. We address both processes (automation and replacement), thereby providing an overview of how the use of AI technologies will—or can—change human-animal relations, at both the individual and societal levels. While doing so, we highlight the morally significant aspects that come along with such changes and provide first thoughts on which uses of AI are welcomed from a perspective of human-animal relations.

Preparation of active zinc oxide from zinc-containing dust and synergistic recovery process of valuable elements

Zinc-containing dust generated from the iron and steel industry is enriched with a large amount of heavy metal substances and rare elements, which is a hazardous waste and a secondary resource. In this study, a new process for the preparation of active zinc oxide and synergistic recovery of valuable elements using zinc-containing dust was proposed. Firstly, a fire process was used to make the valuable components such as Zn, Cd, K, Na, Pb, Bi, In and Sn secondary enriched in the zinc-rich dust. Then the leaching and recovery of K (99.74 %) and Na (98.12 %) were realized by alkaline washing method taking advantage of the solubility difference. Thermodynamic analysis showed that controlling the pH of the leaching system could realize the selective separation of the valuable components. The experimental results showed that the leaching rates of Zn and Cd reached 86.95 % and 92.28 %, respectively, under the optimal experimental conditions, while Pb, Sn, Bi and In were enriched in the neutral leaching slag. Cd sponge (70.3 %) was obtained after the neutral leach solution was treated by Zn powder replacement process. The purified zinc sulfate solution was used to prepare active zinc oxide (97.04 %) by direct precipitation at a molar ratio of CO32–/Zn2+ of 1.15 and a temperature of 50 °C. The average particle size of the product was 21.95 nm, which was in accordance with the industry standard. Neutral leaching slag realized Bi (91.5 %), Sn (71.01 %) and In (94.0 %) in high acid leaching process, and Pb was enriched in slag in the form of PbSO4. The high acid leach solution is hydrolyzed, extracted and replaced to obtain BiOCl, crude tin and crude indium. This process realizes the comprehensive recovery and high-value utilization of various valuable elements in zinc-containing dust sludge, and has significant environmental, economic and social benefits.

Adult-neurogenesis allows for representational stability and flexibility in early olfactory system.

In the early olfactory system, adult-neurogenesis, a process of neuronal replacement results in the continuous reorganization of synaptic connections and network architecture throughout the animal's life. This poses a critical challenge: How does the olfactory system maintain stable representations of odors and therefore allow for stable sensory perceptions amidst this ongoing circuit instability? Utilizing a detailed spiking network model of early olfactory circuits, we uncovered dual roles for adult-neurogenesis: one that both supports representational stability to faithfully encode odor information and also one that facilitates plasticity to allow for learning and adaptation. In the main olfactory bulb, adult-neurogenesis affects neural codes in individual mitral and tufted cells but preserves odor representations at the neuronal population level. By contrast, in the olfactory piriform cortex, both individual cell responses and overall population dynamics undergo progressive changes due to adult-neurogenesis. This leads to representational drift, a gradual alteration in sensory perception. Both processes are dynamic and depend on experience such that repeated exposure to specific odors reduces the drift due to adult-neurogenesis; thus, when the odor environment is stable over the course of adult-neurogenesis, it is neurogenesis that actually allows the representations to remain stable in piriform cortex; when those olfactory environments change, adult-neurogenesis allows the cortical representations to track environmental change. Whereas perceptual stability and plasticity due to learning are often thought of as two distinct, often contradictory processing in neuronal coding, we find that adult-neurogenesis serves as a shared mechanism for both. In this regard, the quixotic presence of adult-neurogenesis in the mammalian olfactory bulb that has been the focus of considerable debate in chemosensory neuroscience may be the mechanistic underpinning behind an array of complex computations.

Investigation of the Driving Force of Replacing Adsorbed Hydrocarbons by CO2 in Organic Matter from an Energy Perspective.

Carbon dioxide (CO2) has been widely used to enhance the recovery of adsorbed hydrocarbons from the organic matter (OM) in shale formations. To reveal the driving force of replacing adsorbed hydrocarbons from OM by CO2, we performed molecular dynamics (MD) simulations of the replacement process and calculated the interaction forces between CO2 and hydrocarbons. In addition, based on the umbrella sampling method, steered MD simulations were performed, and the free energy profiles of hydrocarbons were obtained using the weighted histogram analysis method. Results show that the condition of the hydrocarbon replacement by CO2 requires the hydrocarbon to have sufficient kinetic energy or to have a sufficiently large attractive force exerted to ensure that the hydrocarbon escapes the potential well of the OM. The attractive forces exerted on hydrocarbon molecules by CO2 can significantly decrease the energy barrier associated with hydrocarbon movement away from the OM surface. Furthermore, both CO2 and supercritical CO2 can effectively displace adsorbed hydrocarbon gas (methane) on the OM, while supercritical CO2 is required to enhance the recovery of adsorbed hydrocarbon oil (n-dodecane). The results obtained in this study provide guidance for enhancing the recovery of adsorbed hydrocarbons by CO2 in shale formations.