Replacement Process Research Articles

Iron, boron, and sulfur isotope constraints on the ore-forming process of subseafloor replacement-style volcanogenic massive sulfide systems

The well-preserved Ashele subseafloor replacement-style volcanogenic massive sulfide (VMS) deposit in the Central Asian Orogenic Belt comprises two stages of Cu mineralization, i.e., early massive sulfides dominated by colloform and euhedral pyrite intergrown with chalcopyrite and sphalerite, which were replaced by late vein-dominated chlorite-chalcopyrite assemblages. In this study, a combined systematic Fe, B, and S isotope investigation was first applied to investigate the sulfide precipitation processes and the relative proportion of fluid sources in different alteration and mineralization stages of the Ashele deposit. Boron isotopes of Mg-rich tourmaline (δ11B from −5.57‰ to −2.73‰, average (avg.) −4.23‰) indicate significant seawater (∼19%) participated during the formation of massive sulfides. A two-component mixing model is used to estimate the contribution of seawater and igneous sulfur to the total sulfur budget, and the results show the increasing contribution of magmatic sulfur from the early (35%) to late (76%) stages. In addition, δ56Fe values of pyrite gradually increase from the massive ore (−0.46‰ to −0.02‰, avg. −0.24‰), quartz-pyrite (−0.09‰ to 0.07‰, avg. −0.01‰), chlorite-chalcopyrite-quartz-pyrite (0‰ to 0.21‰, avg. 0.08‰) to the quartz-sericite zone (−0.02‰ to 0.29‰, avg. 0.14‰), which is likely related to the different extent of isotopic exchange and formation temperature, and could be used in the exploration of VMS systems. The new two-stage ore-forming model shows that in the early stage, rapid mixing of hydrothermal fluid from underlying magma chamber with abundant cold seawater led to rapid deposition of pyrite and associated Cu mineralization under relatively oxidized condition, and long-term hydrothermal activities in relatively closed systems would promote the formation of upper massive ores, which resulted in an equilibrium system between pyrite, chalcopyrite, and associated fluid with wide ranges of δ56Fe in pyrite (−0.46‰ to −0.02‰) and chalcopyrite (−1.56‰ to −0.49‰). The late hydrothermal activities in relatively open system would contribute to stringer sulfides or stockworks underlying the massive ore in relatively reduced conditions with heavier Fe isotope compositions in pyrite (−0.09‰ to 0.29‰) and chalcopyrite (−0.60‰ to −0.04‰). Overall, our study demonstrates that the coupling of B, Fe, and S isotopes could be a useful tool to indicate long-term subseafloor infilling and replacement processes for subseafloor replacement-type VMS deposits, which are the prerequisite to form large-tonnage VMS deposits.

Unusual promotion/inhibition effect of polyethylenimine on CO2/CH4 hydrate formation: A potential green chemical additive for CH4-CO2 replacement process

The unusual behavior of a new class of compounds that selectively function as either promoters or inhibitors of gas hydrate formation depending on the process conditions has made their exploration increasingly appealing. In this study, polyethylenimine (PEI) exhibits desirable functionality that may be a candidate for environmentally benign compounds. The present work investigated PEI's thermodynamic and kinetic influence on the formation of CH4 and CO2 hydrates for two PEI concentrations (0.5 and 5.0 mass%) and two PEI molecular weights (25,000 and 750,000 g/mol). The isochoric method was applied to measure the hydrate-liquid water–vapor-three-phase-coexisting (H-LW-V-3PC) phase boundary. PEI is a thermodynamic inhibitor regardless of CH4 or CO2 as a hydrate former, and 0.5 mass% PEI system exhibits the highest average suppression temperatures of 0.25 and 0.62 K, respectively. Kinetic findings, such as induction time, initial hydrate formation rate, and nucleation rate, on the other hand, revealed that PEI could act differently in response to specific hydrate formers. PEI kinetically inhibits CH4 hydrates formation but promotes the formation of CO2 hydrates. This promotion effect is attributed to PEI's high CO2 absorption ability to enhance the solubility of CO2. This unique behavior of PEI presents appealing advantages in the natural gas hydrate exploitation field due to their potential for greater operational flexibility and minimal environmental impact.

Hydrological changes regulate fish metacommunity structures and β-diversity patterns in the floodplain lake, China

The metacommunity structures are continuously dynamic, and understanding the temporal species distribution patterns and biodiversity variations will elucidate the metacommunity theory. To examine whether the idealized metacommunity structuring, diversity patterns, and potential driving mechanisms vary among different seasons, we assessed seasonal fish data (i.e., normal, wet, and dry seasons) in the Poyang Lake, the largest freshwater lake in China, by incorporating the Elements of Metacommunity Structure (EMS), β-diversity partitioning, and variance partitioning. The results suggested fish metacommunity displayed quasi-structures, with the quasi-Clemensian paradigm in the normal season and the quasi-Gleasonian paradigm in the wet and dry seasons, indicating the unity of species groups and individualistic species responded weakly to latent environmental gradients, respectively. The highest fish β-diversity occurred in the normal season and the lowest in the wet season with a humped trend. The species abundance replacement process contributed more to the total β-diversity than the nestedness-resultant component among seasons. The variation of the highest Local Contribution to Beta Diversity (LCBD) across seasons indicated the significance of protecting unique habitats. The relative importance of environment and spatial factors on fish metacommunity structure depended on discharge alternation, with a more significant role of spatial structuring occurring in the wet season, whereas predominant environmental filtering in the normal and dry seasons. The seasonal shifts in EMS patterns, β-diversity, and metacommunity assembly rules result from the change in hydrological conditions in the Poyang Lake. This work helps understand seasonal metacommunity dynamics and provides essential information for systematic biodiversity conservation planning in freshwater lakes.

Rewiring of Aminoacyl-tRNA Synthetase Localization and Interactions in Plants With Extensive Mitochondrial tRNA Gene Loss.

The number of tRNAs encoded in plant mitochondrial genomes varies considerably. Ongoing loss of bacterial-like mitochondrial tRNA genes in many lineages necessitates the import of nuclear-encoded counterparts that share little sequence similarity. Because tRNAs are involved in highly specific molecular interactions, this replacement process raises questions about the identity and trafficking of enzymes necessary for the maturation and function of newly imported tRNAs. In particular, the aminoacyl-tRNA synthetases (aaRSs) that charge tRNAs are usually divided into distinct classes that specialize on either organellar (mitochondrial and plastid) or nuclear-encoded (cytosolic) tRNAs. Here, we investigate the evolution of aaRS subcellular localization in a plant lineage (Sileneae) that has experienced extensive and rapid mitochondrial tRNA loss. By analyzing full-length mRNA transcripts (PacBio Iso-Seq), we found predicted retargeting of many ancestrally cytosolic aaRSs to the mitochondrion and confirmed these results with colocalization microscopy assays. However, we also found cases where aaRS localization does not appear to change despite functional tRNA replacement, suggesting evolution of novel interactions and charging relationships. Therefore, the history of repeated tRNA replacement in Sileneae mitochondria reveals that differing constraints on tRNA/aaRS interactions may determine which of these alternative coevolutionary paths is used to maintain organellar translation in plant cells.

Where didwergo? Lexical variation and change in third-person male adult noun referents in Old and Middle English

AbstractThe present study uses variationist quantitative methods to examine the evolution of the semantic field of third-person male adult noun referents from Old English to Middle English, covering a time depth of approximately six hundred years. Results show a shift from the favored variantwerin Old English tomanin Middle English, with the diachronic change in frequency following a prototypical s-shaped distribution. Although the replacement seems to take centuries to be complete, lexical frequency and written transmission are proposed as influential explanatory factors, and a homonymic clash is suggested to have accelerated the process of replacement in Middle English. Text type and text origin contribute to variation, with alliteration significantly influencing lexical choices in Old English verse texts. When combined with findings from recent synchronic work, this study highlights a heterogeneously structured semantic domain, which has undergone lexical replacement and change over time, providing some evidence for the applicability of s-shaped patterns for lexical change.

Pengembangan Standard Operating Procedure Penggantian Tire pada Raw Mill Pabrik X

Cement production requires several tools to process raw materials. One of the processes is raw mill, where one of the components involved is the Tire Roller. Tire Roller serves to grind the mixed material into fine quality. The replacement process is scheduled when the tire's service life is over to keep the production process running. Completeness of SOP is still one of the deficiencies in the tire replacement process at Factory X. Preliminary studies show that the standard time for each activity needs to be added to the existing SOP. This study aims to complete the SOP for the tire replacement process through three stages: (1) Interviews with various related parties, both directly and indirectly; (2) Examination of the completeness of existing SOPs; and (3) Calculation of the standard time for each activity. The development of SOP for replacing tire rollers in raw mills was successfully carried out by adding several activities and standard times for each activity. This result is expected to increase the efficiency of the raw mill maintenance process.

Three-phase-boundary Pt in a self-supported MoPt2-MoNi4/Mo2C heterojunction electrocatalyst for highly efficient pH-universal hydrogen evolution reaction

Design of high-performance Pt-based electrocatalysts is significant for hydrogen production through water splitting at pH-universal conditions but still challenging. Herein, the MoPt2-MoNi4/Mo2C three-phase heterojunction is fabricated via simply pyrolyzing hydrothermally resultant Mo-Ni precursor with subsequent galvanic Pt replacement process. It exhibits remarkable and stable hydrogen evolution reaction (HER) performance with impressive mass activity and low overpotential of 53, 77 and 46 mV at the current density of 100 mA cm−2 in alkaline, neutral and acidic media, respectively. Density functional theory calculations illustrate that there are multiple types of Pt sites in the phase of MoPt2 in such three-phase heterojunction, while only the Pt atoms located in the three-phase boundary not only process optimal electronic structure modulated by MoNi4/Mo2C, but also act as highly-active sites for HER. Moreover, downshifted d-band center of Pt triggered by the construction of three-phase MoPt2-MoNi4/Mo2C heterojunction, which regulating the free energy of reactive intermediates sorption and thereby accelerating the entire HER process. This work provides some constructive suggestions to design highly efficient Pt-based heterostructured electrocatalysts towards HER.

Strategi Penjadwalan Penggantian Roll Pada Mesin Rolling Mill Di PT. Z

PT. Z is one of the companies that produces steel plates located in Surabaya, East Java. Production process at PT. The Z fully uses machines that operate 24 hours a day. The bottleneck in the steel plate production process is that there are often breakdowns caused by people, machines, and materials. In the engine factor, there is often a machine breakdown that makes production stop. The smooth running of the production process is disrupted due to damage to the production machine. High downtime often occurs due to repairs and replacement of components in certain machine parts. Therefore the machine needs maintenance / maintenance (maintenance). Among all production machines, rolling mill machines are the machines with the highest downtime rates. The components in the rolling mill machine that cause the highest downtime of 12,851 minutes are roll components. This study intends to make a scheduling plan for roll replacement on rolling mill machines. The methodology used in this study is Preventive Maintenance by calculating its reliability and making a schedule for replacing and maintaining the machine. The results showed that the average roll replacement every 6 days with 63.21% reliability, and the average roll replacement process time was 131 minutes.

Environmental Benefit Assessment of Second-Life Use of Electric Vehicle Lithium-Ion Batteries in Multiple Scenarios Considering Performance Degradation and Economic Value.

Second-life use of electric vehicle lithium-ion batteries (LIBs) is an inevitable trend; however, battery performance degradation increases environmental loads. This study evaluated the life cycle environmental impacts of second-life use of LIBs in multiple scenarios, considering performance degradation and economic value. The results showed that a component replacement rate of retired LIBs below 50% made the batteries worthy of repurposing. Reusing whole packs of retired LIBs was better than using only cells or modules owing to the environmental loads from diagnosis, disassembly, replacement, and test processes. The battery energy density and performance degradation significantly affect the maximum return on the environmental input. Compared with lithium iron phosphate (LFP) batteries, new lithium nickel manganese cobalt oxide (NMC) batteries, or lead-acid batteries, using retired NMC-811 batteries with capacities as low as 60.7% for energy storage systems to store wind electricity rather than hybrid or photovoltaic electricity, had substantial environmental benefits, including a low global warming potential. Considering the costs of battery recycling, labor, and electricity, using whole packs of retired LIBs could simultaneously achieve high economic and environmental values in energy storage and peak shaving scenarios.

Compositional variation in grassland plant communities

AbstractHuman activities are altering ecological communities around the globe. Understanding the implications of these changes requires that we consider the composition of those communities. However, composition can be summarized by many metrics which in turn are influenced by different ecological processes. For example, incidence‐based metrics strongly reflect species gains or losses, while abundance‐based metrics are minimally affected by changes in the abundance of small or uncommon species. Furthermore, metrics might be correlated with different predictors. We used a globally distributed experiment to examine variation in species composition within 60 grasslands on six continents. Each site had an identical experimental and sampling design: 24 plots × 4 years. We expressed compositional variation within each site—not across sites—using abundance‐ and incidence‐based metrics of the magnitude of dissimilarity (Bray–Curtis and Sorensen, respectively), abundance‐ and incidence‐based measures of the relative importance of replacement (balanced variation and species turnover, respectively), and species richness at two scales (per plot‐year [alpha] and per site [gamma]). Average compositional variation among all plot‐years at a site was high and similar to spatial variation among plots in the pretreatment year, but lower among years in untreated plots. For both types of metrics, most variation was due to replacement rather than nestedness. Differences among sites in overall within‐site compositional variation were related to several predictors. Environmental heterogeneity (expressed as the CV of total aboveground plant biomass in unfertilized plots of the site) was an important predictor for most metrics. Biomass production was a predictor of species turnover and of alpha diversity but not of other metrics. Continentality (measured as annual temperature range) was a strong predictor of Sorensen dissimilarity. Metrics of compositional variation are moderately correlated: knowing the magnitude of dissimilarity at a site provides little insight into whether the variation is driven by replacement processes. Overall, our understanding of compositional variation at a site is enhanced by considering multiple metrics simultaneously. Monitoring programs that explicitly incorporate these implications, both when designing sampling strategies and analyzing data, will have a stronger ability to understand the compositional variation of systems and to quantify the impacts of human activities.

Chemical Structure of Organic Matter of Agrochernozems of Different Alocalization on the Slope

The chemical structure of organic matter (OM) pools in agrochernozems confined to different zones of denudation-accumulation has been studied by solid-state 13C-NMR spectroscopy. It was revealed that in the erosion zone there are two competing processes occurring simultaneously: the decomposition of the “old” OM of the earlier underlying horizon and the stabilization of the fresh OM that has arrived with plant remains of cultivated plants (dynamic replacement of OM). Analytical data allow us to assert that the processes of dynamic replacement of eroded OM in the erosive zone quite effectively compensate for the processes of OM decomposition, as evidenced by the highest C/N ratio of all the studied OM pools in the eroding agrochernozem, along with the absence of significant differences in the integral indicators of their chemical structure. However, the constant removal of the upper soil layer from the eroding agrochernozem during each erosion event does not allow one to fully compensate for the OM quantitative losses in it. During the transportation of eroded material to the accumulative zone, the most labile part of OM can be mineralized. Accordingly, the OM again entering the accumulative zone is more transformed than that of the eroding agrochernozem. Nevertheless, the alluvial agrochernozem is characterized by an increased level of C accumulation in the soil as a whole and in all the studied OM pools. Accordingly, it can be stated that the constant OM inputs from the eroding position with its subsequent burial with each subsequent erosion event, as well as the repacking/aggregation of newly deposited OM, very effectively contribute to the deposition of C in the accumulative zone.

Effect of Reaction Temperature on the Microstructure and Properties of Magnesium Phosphate Chemical Conversion Coatings on Titanium.

Magnesium phosphate (MgP) has garnered growing interest in hard tissue replacement processes due to having similar biological characteristics to calcium phosphate (CaP). In this study, an MgP coating with the newberyite (MgHPO4·3H2O) was prepared on the surface of pure titanium (Ti) using the phosphate chemical conversion (PCC) method. The influence of reaction temperature on the phase composition, microstructure, and properties of coatings was systematically researched with the use of an X-ray diffractometer (XRD), a scanning electron microscope (SEM), a laser scanning confocal microscope (LSCM), a contact angle goniometer, and a tensile testing machine. The formation mechanism of MgP coating on Ti was also explored. In addition, the corrosion resistance of the coatings on Ti was researched by assessing the electrochemical behavior in 0.9% NaCl solution using an electrochemical workstation. The results showed that temperature did not obviously affect the phase composition of the MgP coatings, but affected the growth and nucleation of newberyite crystals. In addition, an increase in reaction temperature had a great impact on properties including surface roughness, thickness, bonding strength, and corrosion resistance. Higher reaction temperatures resulted in more continuous MgP, larger grain size, higher density, and better corrosion resistance.

NCache: A Machine-Learning Cache Management Scheme for Computational SSDs

Inside a solid-state disk (SSD), cache stores frequently accessed data to shorten user-I/O response time and reduce the number of read/write operations in flash memory, thereby improving SSD performance and lifetime. Most existing cache schemes anchor in the spatiotemporal locality of I/O requests in workloads. In the face of a long-time workload, high performance and hit rate often get lost in these caching schemes. Flash memory-aware caching schemes trade hit ratio to prolong SSD lifetime. In this paper, we advocate for a machine learNing-based caching scheme named NCache to optimize both hit ratio and SSD performance. In NCache, we construct a machine learning (i.e., ML) model to predict whether data are re-accessed before being evicted from the cache. The cache replacement scheme preferentially evicts data that would not be accessed in the cache. The cache space is conserved for valid data that are likely to be repeatedly accessed. A pipelined scheme is implemented to accelerate the ML model, alleviating the time-cost of NCache. A double-linked list boosts the data addressing and cache replacement process. NCache is orthogonal to the existing caching schemes within the flash translation layer. The results validate NCache under a handful of real-world enterprise traces. Taking prn_0 as an example, NCache reduces the response time of LRU, CFLRU, GCaR_LRU, GCaR_CFLRU, and LCR by up to 15% with an average of 6.4%. The erase count is slashed by 16% at the maximum. Importantly, NCache is adroit at optimizing write amplification by up to 15.9%.

Methane replacement by using CO2/C3H8 mixtures for carbon storage and enhanced methane recovery in gas hydrates

The storage of gases via hydrates formation can be enhanced with several different techniques; for instance, the addition of promoting additives helps in reducing the pressures required for the process. However, most of strategies used for gas storage cannot help during replacement processes. This article deals with the hypothesis that the usage of moderate concentrations of small – chain hydrocarbons can absolve both the purposes at the same time. In particular CO2 storage and CH4 replacement were tested with the addition of propane. Three different concentrations of propane in mixture with carbon dioxide were selected, or 0.05, 0.10 and 0.15 mf. Hydrates were formed with each of them and the results discussed in order to identify the better solution in terms of hydrates produced and, mostly, quantity of CO2 stored. The selected concentration was then used for the replacement of methane and the results discussed in order to reveal the benefits obtained in terms of both CO2 stored and CH4 recovered, in comparison with the maximum results theoretically achievable in replacement tests carried out exclusively with pure carbon dioxide.

Metasomatic alteration of zircon at lower crustal P-T conditions utilizing alkali- and F-bearing fluids: Trace element incorporation, depletion, and resetting the zircon geochronometer

Natural alteration of zircon takes place in melts or fluids either via dissolution coupled with overgrowth or via a coupled dissolution-reprecipitation process. The latter results in the zircon being partially or totally replaced by new, compositionally re-equilibrated zircon or a new mineral phase or both. In this study, fragments (50–300 μm) from a large, inclusion-free, clear, 520–530 Ma euhedral zircon with light radiation damage from a nepheline syenite pegmatite, Seiland Igneous Province, northern Norway, were experimentally reacted in 20 mg batches with 5 mg of ThO2 + ThSiO2 + SiO2 and a series of alkali-bearing fluids in sealed Pt capsules at 900 °C and 1000 MPa for 6–11 days in the piston cylinder press using a CaF2 setup with a cylindrical graphite oven. ThO2 + ThSiO2 + SiO2 was present at the end of the experiment. In experiments involving H2O, H2O + NaCl, H2O + KCl, and 2 N KOH, no reaction textures formed other than a slight dissolution of the zircon grain fragments. Experiments involving 2 N NaOH, Na2Si2O5 + H2O, and NaF + H2O resulted in zircon reaction textures with varying degrees of intensity, which took the form of partial replacement by compositionally modified zircon via a coupled dissolution-reprecipitation process. In the NaF + H2O experiment some overgrowth also occurred. Altered zircon is separated by sharp compositional boundaries from unaltered zircon. Secondary ion mass spectrometry (SIMS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis indicates that, relative to the unaltered zircon, the altered zircon is strongly enriched in Th, and heavily to moderately depleted in U and (Y + REE). In all the experiments, 206Pb (3–5 ppm in unaltered zircon) is depleted in the altered zircon to below the SIMS detection limit and to at or below the LA-ICP-MS detection limit. Hafnium and Ti concentrations in the altered zircon retained the same approximate value (within error) as the original zircon. The results from these experiments demonstrate that zircon can be compositionally modified by alkali-bearing and alkali-F-bearing fluids via a coupled dissolution-reprecipitation process. Near to total loss of radiogenic Pb via such processes under high-grade conditions resets the internal zircon geochronometer. Although the end result is the same as with zircon overgrowth, i.e. the production of new generation zircon at the time of a metamorphic/metasomatic event, such replacement processes can explain incomplete isotopic ‘resetting’; inclusion production through unmixing of solid solutions in metastable zircon compositions; and ‘ghost’ textures that preserve initial growth features but with isotopic disturbance. Diagnostic replacement features produced in experiments, such as interface geometries between altered and unaltered zircon, provide markers of the mechanism and aid in zircon interpretation. A major implication from this study is that if zircon with low radiation damage can be metasomatically altered under high-grade conditions, this would have important consequences with respect to zircons presumed role as an impregnable container for mineral inclusions. Namely the mineral inclusions contained within zircon could also be altered, reset as a geochronometer, or even replaced by another mineral.

In Situ Structure Refactoring of Bismuth Nanoflowers for Highly Selective Electrochemical Reduction of CO2 to Formate

AbstractThe electrocatalytic CO2 reduction reaction (CO2RR) has been considered a promising route toward carbon neutrality and renewable energy conversion. At present, most bismuth (Bi) based electrocatalysts are adopted to reduce CO2 to formate (HCOOH). However, the mechanism of different Bi nanostructures on the electrocatalytic performance requires more detailed exposition. Herein, a combined chemical replacement and electrochemical reduction process is reported to realize in situ morphology reconstruction from Bi@Bi2O3 nanodendrites (Bi@Bi2O3‐NDs) to Bi nanoflowers (Bi‐NFs). The Bi@Bi2O3‐NDs are proven to undergo a two‐step transformation process to form Bi‐NFs, aided by Bi2O2CO3 as the intermediate in KHCO3 solution. Extensive surface reconstruction of Bi@Bi2O3‐NDs renders the realization of tailored Bi‐NFs electrocatalyst that maximize the number of exposed active sites and active component (Bi0), which is conducive to the adsorption and activation of CO2 and accelerated electron transfer process. The as‐prepared Bi‐NFs exhibit a Faradaic efficiency (FEformate) of 92.3% at −0.9 V versus RHE and a high partial current density of 28.5 mA cm−2 at −1.05 V versus RHE for the electroreduction of CO2 to HCOOH. Moreover, the reaction mechanism is comprehensively investigated by in situ Raman analysis, which confirms that *OCHO is a key intermediate for the formation of HCOOH.

OPTIMIZATION OF THE REPLACEMENT PROCESS FOR THE BRAKE SHOES ISUZU GIGA TRUCK AT PT AI-ISO DM JAKARTA BRANCH

PT AI-ISO workshop on DM Jakarta provides various repair and periodic maintenance services. In periodic maintenance, brake repair jobs have problems replacing the brake pads (brake shoe set) of Isuzu Giga Trucks, which takes about 9 hours. To reduce the processing time, an improvement process is carried out to shorter processing time, so the customer feels more satisfied with repairing his vehicle. From observations, the length of work time was due to the process of changing the brake pads outside the workshop due to the absence of tools to install the brake pads. The repair shop offers to replace a set of brake pads, but the price is higher than just replacing the brake pads, so the customer makes this choice. The improvement made was the manufacture of a rivet installation tool on the brake pads based on the workings of a rivet machine. First, it is necessary to make a brake pad holder so that it does not shift when pressed and ensures that the pressure acting on the rivet is as requested. This tool is also equipped with a Standard Operation Procedure to make it easier for technicians to replace brake pads. The result is a decrease in processing time for the brake pad replacement process from an average of 9 hours to 5 hours. With these tools, repairing the brake system can be accelerated and within the safe limits required in the vehicle's manual, and the customer will be more satisfied.

Constructing a Demand-Driven College English Learning Environment in Higher Education Institutions

ABSTRACT This paper aims to introduce a new approach to enhance college English learning through an intelligent method that constructs a learning environment from a demand analysis perspective. The proposed model utilizes a bionic algorithm to structure the algorithm and adopts a highly efficient energy generation method to calculate the interaction energy. This study aims to find the optimal solution to the constraint problem by using a process of continuous generation, expansion, and replacement of magnetosomes. The methodology employed in this research involved constructing the college English learning environment in colleges and universities from a demand analysis perspective. This was achieved by analyzing the needs and requirements of college students and designing an ecological virtual learning environment (EVLE) that meets their demands. The findings of this study indicate that the proposed EVLE for college English is effective in improving the effectiveness of college English learning. The experimental verification results support the effectiveness of the proposed model in creating an interactive and engaging learning environment that facilitates the acquisition of English language skills. It is an innovative approach to college English learning that utilizes intelligent methods to construct a demand-driven learning environment that enhances students’ learning outcomes.

Research on Improved DNA Coding and Multidirectional Diffusion Image Encryption Algorithm.

In order to make the security and operating efficiency of an image encryption algorithm coexist, this study proposed a color image encryption algorithm with improved DNA coding and rapid diffusion. During the stage of improving DNA coding, the chaotic sequence was used to form a look-up table to complete the base substitutions. In the replacement process, several encoding methods were combined and interspersed to make the randomness higher, thereby improving the security performance of the algorithm. In the diffusion stage, three-dimensional and six-directional diffusion was performed on the three channels of the color image by taking the matrix and the vector as the diffusion unit successively. This method not only ensures the security performance of the algorithm, but also improves the operating efficiency in the diffusion stage. From the simulation experiments and performance analysis, it was shown that the algorithm has good encryption and decryption effects, large key space, high key sensitivity, and strong security. The algorithm can effectively resist differential attacks and statistical attacks, and has good robustness.

Unique dentition of rhynchosaurs and their two‐phase success as herbivores in the Triassic

AbstractRhynchosaurs were key herbivores over much of the world in the Middle and Late Triassic, often dominating their faunas ecologically, and much of their success may relate to their dentition. They show the unique ankylothecodont mode of tooth implantation, with deep roots embedded in the bone of the jaw and low crowns that were rapidly worn down in use. During growth, the main area of oral food processing, located in the middle and posterior portions of the occlusal surfaces of the jaws, moved posteriorly relative to the anterior tips of the jaws, which curved up. As the maxilla and dentary grew by addition of new bone posteriorly, the dental lamina fed in new teeth at the back of the tooth rows. CT scanning of the holotype skull of Bentonyx sidensis from the Middle Triassic of England reveals previously concealed details of the dentition. Together with new dentary material from the same location, this has enabled us to examine the tooth replacement process and elucidate ontogenetic changes in dentition and jaw morphology as the animals aged. There were major changes in rhynchosaur anatomy and function through their evolutionary history, with the early forms of the Middle Triassic dying out before or during the Carnian Pluvial Episode (233–232 Ma), and the subclade Hyperodapedontinae, with broad skulls and adaptations to chop tough vegetation, subsequently diversifying worldwide in a successful ecological expansion until their global extinction 227–225 Ma.