Transformation Characteristics Research Articles

Reaction-controlled shape evolution and insights into the growth mechanism of CsPbBr3 nanocrystals

The correlation between structural transformation and optical characteristics of cesium lead bromide (CsPbBr3) nanocrystals (NCs) suggests insights into their growth mechanism and optical performance. Systematic control of reaction parameters led to the successful fabrication of on-demand shape-morphing CsPbBr3 NCs. Transmission electron microscopy observations showed that the shape transformation from nanocubes to microcrystals could be accelerated by increasing the precursor:ligand molar ratio and reaction time. Further evidence for orthorhombic CsPbBr3 NCs was obtained from their selected-area electron diffraction pattern, which exhibits a twin domain induced by the presence of large NCs. Likewise, we observed a substantial decrease in photoluminescence (PL) intensity of CsPbBr3 due to surface decomposition or surface ligand loss resulting from increased size. In addition, fusion of smaller particles having other dimensionality induced the increase in the PL full-width at half maximum. In particular, existence of larger bulk material caused a reduction in the peak intensity in the absorption spectra and a trend of decreasing tendency in intensity of the absorption bands related to bromoplumbate species provided direct evidence of fully converted Cs-oleate.

Wave trapping by porous breakwater near a rigid wall under the influence of ocean current

The present work investigates the water wave interaction with bottom-standing thick porous trapezoidal-shaped structures and shore-side vertical rigid wall in the presence of uniform ocean currents. This study has been done to understand the impact of different physical parameters like friction, porosity, and ocean currents along with different structural parameters (width and height) on different phenomena like wave energy reflection, wave forces, wave energy dissipation, etc. The quadratic boundary element method-based numerical technique has been used to solve the boundary value problem. The structural porosity is modeled using Sollitt and Cross’s model of water wave interaction with thick porous structures. Several results associated with the wave energy reflection and energy dissipation have been analyzed. Also, the wave force exerted by the incoming waves has been investigated to check the stability and sustainability of the right vertical rigid wall and porous structure. The Doppler-shift effect is observed in wave transformation characteristics due to the presence of ocean currents. The impact of following and opposing ocean currents can be seen in the graph of wave energy reflection, dissipation, and wave forces. The periodic patterns can be observed clearly in wave characteristics like wave energy reflection, dissipation, and wave forces when plotted against the non-dimensional separation gap between the porous breakwater and shore-side rigid seawall.

Characteristics and Influencing Factors of Landscape Pattern Gradient Transformation of Small-Scale Agroforestry Patches in Mountain Cities

Small-scale agroforestry patches possess irreplaceable value compared to large-scale patches. In southwestern mountainous cities of China, the complex terrain and urbanization have led to the presence of numerous small, fragmented agroforestry patches around urban areas. These patches serve as crucial habitats for endemic species and provide essential space for wild food sources, thereby contributing to a range of ecosystem services. Consequently, their proper conservation and utilization planning are of paramount importance. This study investigates the transformation characteristics of landscape patterns of mountainous small-scale agroforestry patches and their constituent elements across urban–rural gradients, identifying the driving factors behind these transformations to support conservation and utilization planning. From an urban–rural gradient perspective, four directional transects were selected and divided into uniform sample grids. Using Fragstats 4.3, landscape indices of small-scale agroforestry patches were calculated, analyzing the transformation characteristics of these patches and their elements across different gradients. Spearman correlation coefficients in SPSS were employed to assess the influence of terrain and relevant anthropogenic factors on the transformation of agroforestry patches. The findings reveal the following: (1) Small-scale agroforestry patches and their elements exhibit similar patterns in terms of size, fragmentation, dispersion, and connectivity, showing an “increasing trend in size and connectivity, decreasing fragmentation, and fluctuating dispersion” from urban centers to natural areas, with slight variations in orchard patches. However, patch cohesion and shape complexity display nonlinear differentiated transformation characteristics. (2) Overall, small-scale agroforestry patches are significantly influenced by anthropogenic construction factors, with the landscape pattern of forest patches notably affected by terrain factors. (3) Across urban–rural gradient zones, the landscape patterns of small-scale agroforestry patches in urban centers, suburbs, and rural natural areas are more affected by terrain factors, whereas those in urban construction zones are significantly influenced by anthropogenic construction factors. The findings of this study provide a scientific basis for the conservation and planning of mountainous small-scale agroforestry patches.

A regenerated cellulose fiber with high mechanical properties for temperature-adaptive thermal management

The escalating global population has led to a surge in waste textiles, posing a significant challenge in landfill management worldwide. In this work, ionic liquid 1-butyl-3-methylimidazole acetate ([Bmim]OAc) and DMF (N, n-dimethylformamide) were used as solvents to dissolve waste denim fabric, then vanadium dioxide (VO2) nanoparticles were introduced into the spinning solution, and cellulose fibers were regenerated by dry-wet spinning process, to promote the recycling of waste cotton fabric. Finally, regenerated cellulose fibers with high added value were prepared by dry-wet spinning. Through this innovative strategy, on the one hand, because VO2 can form a large number of hydrogen bonds between the regenerated cellulose molecules, and realize the cross-networking structure of the molecular chains inside the fiber, the mechanical properties of the regenerated cellulose fibers are enhanced. On the other hand, due to the thermal phase transformation characteristics of VO2, it also endows the regenerated cellulose fiber unique intelligent temperature control function. Compared with the pristine regenerated fiber, the tensile stress of the regenerated fiber after adding VO2 nanoparticles (F-VO2) increased by 25.6 %, reaching 158.68 MPa. In addition, the F-VO2 fibric provides excellent intelligent temperature control, reducing temperatures by up to 6.7 °C.

Effect of heat treatment conditions on the phase transformation characteristics of nitinol

Nitinol is the most widely used shape memory alloy in medical applications. In this study, the effect of different heat treatment conditions on the phase transformation characteristics of medical-grade nitinol was investigated. Nickel-rich nitinol wires containing 50.6% nickel with a diameter of 120 μm were used in the experimental studies. The nitinol wires were heat treated for 10 minutes at heat treatment temperatures between 540 and 570 °C. Then, nitinol wires were heat treated at a heat treatment temperature of 550 °C between 8 and 14 minutes. The austenitic and martensitic transition temperatures of these samples were measured using differential scanning calorimetry (DSC). In the experiments with 10 minutes of heat treatment time, transition temperatures decreased, and hysteresis increased with the increase in heat treatment temperature. This is related to the amount of precipitates in the structure. In the experiments carried out at 550 °C, transition temperatures decreased, and hysteresis increased with increasing heat treatment time. Experimental studies showed that the austenite finish (Af) temperature of all nitinol wire samples was below 37 °C, and they will exhibit superelasticity in the human body.

Influence of Individual Consideration on Organizational Performance on private Universities in Nairobi County, Kenya

Transformational leadership is a process in which leaders and followers help each other to advance to a higher level of morale and motivation, creating significant changes in the lives of people and organizations. The purpose of the study was to investigate the influence of individualized consideration style on organization performance in private universities in Nairobi City County, Kenya. The objective that guided the study was to: establish the influence of individualized consideration on organizational performance in private universities in Nairobi City County, Kenya. The study used Transformational Leadership Theory by Burns (1978) and the conceptual framework was based on the relationship between individualized consideration style and organizational performance. The sample comprised of 288 lecturers and 7 Deans of Academic Affairs of the chartered private universities, and questionnaires and interview guides were used to gather data. Validation of the questionnaires was through Cronbach’s Alpha and the use of expert judgement. The coefficient value was 0.879 at alpha = 0.05. Data was analyzed using both descriptive and inferential statistics, and the regression analysis showed a strong relationship between individualized consideration and the performance of private universities. The results revealed a positive and significant relationship between individualized consideration (β = .370, p<.05). It was concluded that offering leadership support and advice, mentorship, career development, and solving individual needs among their employees influences performance. The following recommendations were made: the management of private universities ought to offer leadership support and advice to their employees as this is important in improving their performance. Furthermore, they should realize that in order to realize higher performance for their institutions they need to ensure that the leaders in the institutions act as both mentors and coaches for the employees and recognize their contributions to the organization. The Deans of Academic Affairs need to attend seminars and training in transformational leadership so that they can be well-versed in transformational leadership skills, responsibilities, and characteristics.

Towards a low-carbon and beautiful world: assessing the impact of digital technology on the common benefits of pollution reduction and carbon reduction.

When ecology thrives, civilization thrives, and when ecology declines, civilization declines. Based on panel data from 30 provinces in China from 2000 to 2021, this study used marginal abatement costs to estimate the co-benefits of pollution reduction and carbon reduction. Two-way fixed effect and two-stage intermediary effect models were used to evaluate the impact of digital technology on co-benefits and its indirect channels. The results indicated that China's total carbon emissions maintained a steady growth trend, while air pollution showed a fluctuating declining trend. Reaching peak carbon neutrality calls for more innovative solutions. Under joint emission reduction efforts, the study revealed marginal abatement cost savings of 535.8 million yuan/million tons and 6216.5 million yuan/μg/m3 for carbon reduction and pollution reduction, respectively. Most importantly, the study confirmed that joint emission reduction programs can reduce environmental governance costs more than individual emission reductions can, and the co-benefits increased from 37.983 to 44.757. The co-benefits generally showed a trend of fluctuation and increases and had the characteristics of phased transformation. Intragroup differences and cross-overlapping between regions made regional differences in co-benefits obvious. The subversive, permeable, and integrated features of digital technology have resulted in the all-around transformation of the economy and society, and the new technology-economy paradigm has significantly improved co-benefits. The conclusion remains valid after robustness testing and controlling for endogeneity problems. The results of the mechanism analysis suggest that digital technology can indirectly improve synergies through the intermediary channels of fostering green technology innovation, reducing energy consumption intensity and improving the energy structure.

Changes in combined toxicity of benzophenone-3 and humic acid on Daphnia magna and zebrafish during chlorination disinfection process

Conventional wastewater treatment methods cannot completely remove the ultraviolet (UV) filters or dissolved organic matter. The transformation characteristics of these substances during chlorination disinfection and the varying species-specific toxicities of their combinations remain unclear. Here, Daphnia magna and zebrafish were exposed to benzophenone-3 (BP-3) and humic acid (HA) before and after chlorination disinfection. The results from chemical indicators showed that chlorination treatment decreased UV254 values and changed the intensity of parallel factors in three-dimensional fluorescence. Based on chemical analysis, the chlorine concentration and chlorination time for the toxicity experiments were set at 5 mg/L and 6 h, respectively. Exposure to HA and BP-3 before and after chlorination decreased the heart rate (by 1.37–28.12 %) in both species. However, species-specific responses, including survival rate, swimming distance, and expression of genes related to neurodevelopment, growth, and oxidative stress, were induced by chlorination. Chlorination reduced the impact of HA exposure but worsened the effects of HA and BP-3 co-exposure on D. magna. However, in zebrafish, the toxic effects intensified in most of the exposure groups after chlorination. Correlation analysis showed that the parallel factors of three-dimensional fluorescence were correlated with toxic effects on zebrafish, whereas UV254 was more significantly correlated with toxic effects on D. magna. This study provides insights into the combined toxicity of UV filters and dissolved organic matter in different aquatic organisms during chlorination, which is useful for risk control and optimization of the chlorination process.

Analysis of nitrogen migration and transformation in the typical deep and large reservoir of the Lancang River — Evidence from nitrogen and oxygen isotopes

The environmental effect resulting from dam construction and the formation of large reservoirs has long been a topic of significant concern. While current research at a macro scale provides a well understanding regarding the evolution of nitrogen nutrient status in river-reservoir ecosystems, the vertical migration and transformation characteristics of nitrogen in reservoirs under changing runoff remain less defined. This study centers on a typical deep reservoir along the Lancang River-Nuozhadu (NZD) Reservoir in April and December. The monitoring reveals a distinct vertical stratification phenomenon in the NZD Reservoir in the vertical profile in April, which can be categorized into a mixed layer (ML) (0–5 m), a thermocline layer (TL) (5–40 m), and an isothermal layer (IL) (>40 m) based on the water temperature. However, little stratification in the profile is occurred in December. The results of nitrogen and oxygen isotopes in April indicate that the biochemical process of nitrogen in the NZD Reservoir is predominantly driven by nitrification. However, different nitrogen biochemical processes are coupled in various stratified regions in the vertical direction. In the ML, simultaneous assimilation of ammonia nitrogen by phytoplankton occurs. In the TL, there is a process of oxidation and decomposition of particulate organic nitrogen due to a significant stratification effect and an extended hydraulic retention time. In the region of minimal dissolved oxygen (30–40 m), simultaneous denitrification may take place. In December, the main process is nitrogen assimilation in reservoir surface (ML). Statistical analysis of environmental factors highlights water temperature (T) and dissolved oxygen (DO) as crucial environmental factors influencing nitrogen migration and transformation within the reservoir. This study suggests that in deep reservoirs experiencing vertical thermal stratification, the characteristics of DO and nitrogen migration and transformation exhibit significant vertical spatial heterogeneity. This phenomenon may lead to diverse ecological environmental effects. Future efforts should focus on enhancing the fine monitoring of stratified water bodies in deep and large reservoirs and analyzing the ecological environmental effects of material cycling in greater detail.

Active interlocking metasurfaces enabled by shape memory alloys

Interlocking metasurfaces (ILMs) are a newly developed joining technology that relies on arrays of interlocking features that transmit force and constrain motion between adjoining bodies in one or more directions. This study explores harnessing the shape memory effect in nickel-titanium shape memory alloys (NiTi SMAs) in structures fabricated using additive manufacturing (AM) to advance the development of active ILMs by creating unit cells that open or close at specific temperatures. The study encompasses designing and fabricating two distinct interlocking array configurations using near-equiatomic NiTi powder and the laser powder bed fusion (L-PBF) AM technique, following a previously developed AM process optimization framework to manufacture defect-free parts. To guide the design process, finite element analysis (FEA) was employed to predict strain values during engage-disengage cycles. The martensitic transformation characteristics of the ILMs were characterized. Thermomechanical testing revealed that the ILMs demonstrate high locking force once engaged, coupled with complete shape recovery and good cyclic stability. Digital image correlation (DIC) was also employed to validate the FEA predictions during the engage-disengage cycles. The results indicate that NiTi SMA-based ILMs can be designed and fabricated into complex shapes using L-PBF. By leveraging the shape memory effect (SME), the functionality of an ILM can be improved upon. The combination of computational modeling, additive manufacturing, and thermomechanical and physical property characterization provides a framework for designing future ILMs out of active materials.

Effect of stabilization and carbonization treatment on the chemical and physical transformation of polyacrylonitrile (PAN) based electrospun carbon nanofibers

The present study delves into the production of carbon nanofibers (CNFs) utilising electrospun polyacrylonitrile (PAN) nanofiber mats, with a specific focus on the influence of oxidative stabilisation and carbonisation treatments. This research aims to thoroughly understand how variations in stabilisation time and temperature, as well as carbonisation temperature, impact the CNFs properties. These properties include fiber size, morphology, chemical and crystal structure transformation, thermal behaviour, and surface characteristics. Our methodology involved a detailed examination of the thermal treatment processes, where we observed a significant decrease in fiber size, though the surface morphology of the fibers remained largely unaffected. We employed Fourier-transform infrared (FTIR) spectroscopy to track the transformation of nitrile groups in PAN to imine groups, which indicated the progression of cyclisation reactions. Complementary analyses through differential scanning calorimetry (DSC) confirmed a high degree of these reactions, particularly at stabilisation temperatures extending to 250 °C and beyond. The cyclisation process was found to be complete during the carbonisation phase, at temperatures reaching 450 °C and above. Further, x-ray diffraction (XRD) patterns offered insight into the changes in the crystal structure, particularly in the packing of the d(002) spacing because of the stabilisation and carbonisation processes. This findings from this study not only elucidate the intricate process of CNFs production from electrospun PAN nanofiber mats but also highlight the critical factors that influence their final properties. These insights are invaluable for the development of advanced CNFs with tailored properties suitable for a range of applications, including but not limited to energy storage, electronics, and as supporting materials in various technological domains.

Mechanical response and phase transformation characteristics of R-phase NiTi shape memory alloy under high strain rate compression

R-phase NiTi shape memory alloy (R-NiTi SMA) has many excellent properties, but there are application problems such as simple structure and high price. High velocity impact welding can effectively solve these problems, but the research on the mechanical response and phase transformation (PT) characteristics of R-NiTi SMA under dynamic deformation is lacking. Therefore, the quasi-static (0.001 s-1) and dynamic (500 s-1, 1000 s-1, 1500 s-1, 2000 s-1) compression experiments were conducted on R-NiTi SMA in this research. The results showed that the true stress-strain curves of R-NiTi SMA during deformation were characterized by three stages, including the superelastic, elastic, and plastic segments. The critical stress of austenite to R (A-R) and R to martensite (R-M) phase transformation increased with the increase of strain rate, and the phase transformation process gradually disappeared when the strain rate exceeded 1000 s-1, which was related to the velocities of A-R and R-M phase transformation. With the increase of strain rate, defects such as dislocations increased and hindered the phase transformation process during unloading, resulting in the increase of A-phase content. In addition, the enthalpy of the deformed samples decreased significantly and the temperature ranges of phase transformation increased slightly. This work deepens the understanding of the dynamic response of R-NiTi SMA and helps to expand the application of high strain rate processing technology in R-NiTi SMA.

Mathematical modeling of water waves interaction with trapezoidal-shaped breakwater in the presence of current

In this study, an investigation is conducted into the interaction between water waves and a bottom-standing, thick, porous, and trapezoidal-shaped breakwater under the influence of an uniform current. This investigation has been conducted using several effect factors, such as the friction coefficient and porosity of the breakwater and ocean currents, to comprehend various phenomena related to wave energy dissipation, wave load, wave transmission, and wave reflection, etc. The boundary element method-based numerical technique is used to solve the associated boundary value problem. The modeling of the porosity of the breakwater structure is done using the Sollit and cross model [CK Sollitt, RH Cross. Wave transmission through permeable breakwaters. Coast Eng. 1972; 1972: 1827–1846.] of water wave passes through thick porous structures. In the presence of the following and opposite currents, the ‘Doppler-shift’ effect is observed in wave transformation characteristics due to the shift in wave frequencies. The wave-blocking phenomenon in open water and porous regions has been demonstrated. The results show that the following and opposing currents shift the frequencies for which optima in wave reflection occurs.

Cooperative roles of twinning, transformation and strain partitioning on the excellent cryogenic strength-toughness synergy of dual-heterogeneous metastable high entropy alloys

In a metastable Fe50Mn30Co10Cr10 high entropy alloy (HEA), a dual-heterogeneous structure, encompassing both grain size and dislocation heterogeneity, has been constructed to obtain excellent cryogenic mechanical performance by varying the annealing temperature (630 and 740 °C) following severe deformation. The HS-630 sample, consisting of recovered coarse-grains (CG), recrystallized fine-grains (FGs) and un-recrystallized ultrafine-grains (UFGs), possesses higher yield strength (YS) of ∼965 MPa, ultimate tensile strength (UTS) of ∼1680 MPa and uniform elongation (UEL) of ∼45 % when compared to the fully-recrystallized HS-740 sample at liquid nitrogen temperature (LNT). The difference in YS is primarily caused by the grain boundary and dislocation strengthening of UFGs, whereas the higher ductility of the HS-630 sample is associated with the hierarchical activation of transformation- and twinning-induced plasticity (TRIP and TWIP) effects, and compatible strain partitioning between heterogeneous domains. The dual-heterogeneity results in different critical stresses of ε-phase nucleation in heterogeneous domains, and promotes sustainable TRIP effect in CGs and the emergence of TWIP effect in UFGs with strain progressing. Moreover, the strain of the ductile transformed ε-phase is mainly accommodated by non-basal slip, which contributes to the strain hardening in the later deformation stage. Furthermore, the higher cryogenic impact toughness of the HS-630 sample can be attributed to the synergistic effects of the fracture mode, the transformation characteristics, and the heterogeneous strain partitioning.

Nitrogen migration and transformation characteristics of the soil in karst areas under the combined application of oxalic acid and urea inhibitors.

We investigated the horizontal migration and transformation of nitrogen in soil with oxalic acid and inhibitors (e.g., nitrification inhibitors, DMPP, urease inhibitors, and NBPT) under different soil water contents to provide a basis for the efficient utilization of nitrogen fertilizer in agricultural production in karst areas. Four nitrogen fertilizers (e.g., ammonium bicarbonate, ammonium sulfate, ammonium chloride, and urea) were applied separately and combined with oxalic acid, DMPP, and NBPT. The ammonium and nitrate nitrogen contents in the different soil layers were measured. The soil columns were cultured through an indoor soil column simulation at water content levels of 30%, 40%, and flooded (50%) for 30 days. Ammonium bicarbonate with inhibitors increased soil NH4 +-N content by 15.42-21.12%. Ammonium sulfate with oxalic acid or NBPT increased soil NH4 +-N content by 27.56-52.25% at 30% and 40% moisture content treatments, compared to ammonium sulfate alone. Urea with DMPP application significantly increased soil NH4 +-N content by 11.93-14.87% at 40% water content and flooded conditions. In all treatments, the NH4 +-N content in the soil treated with 30% water content of ammonium chloride with oxalic acid was the highest. The NH4 +-N content showed a decreasing trend with an increase in the water content. The NO3 --N content in soil treated with ammonium bicarbonate and DMPP was higher than that treated with other nitrogen fertilizers at 30% moisture. The NO3 --N content decreased with increased water content. Under all treatments, ammonium chloride with oxalic acid had the highest percentage of soil NH4 +-N and soil soluble inorganic nitrogen at 30% water content, with 55.29% and 55.97%, respectively. Among the nitrogen fertilizer treatments, the soil NH4 +-N content increased in ammonium bicarbonate with DMPP or NBPT, ammonium sulfate with oxalic acid or NBPT, and urea with DMPP. The four nitrogen fertilizers with DMPP increased the soil NO3 --N content. Nitrogen fertilizer combined with oxalic acid and inhibitors could effectively improve the effective use of nitrogen fertilizer.

Martensite transformation characteristics in the heat affected zone of laser cladding on rail

This paper studied the macroscopic morphology and properties of the heat affected zone (HAZ) in multi-layer multi-track cladding layers on rail. The results showed that in the two-layer laser cladding, there are martensitic structures and cracks in the HAZ. With the increase of the number of laser cladding layers, the tempering structure in the HAZ expands gradually from the bottom to the top, from the middle to the edge, and no cracks appear in the HAZ. At ten-layer laser cladding, the martensitic structure has been completely eliminated and transformed into tempered sorbite. Finally, the hardness test shows that the hardness of cladding layer, HAZ and substrate are basically the same, which meets the performance requirements of rail repair.

Evaluation and influencing factors of green transformation in three major urban agglomerations in China

Since the 21st century, the world has increasingly focused on the issue of sustainable development, and the green transformation issues have become a new hot topic worldwide. Green and low-carbon transformation has become an international consensus. Urban agglomerations are important connections between urban development and regional coordination, as well as important spatial carriers for economic activities. They are not only the main source of carbon emissions, but also the main battlefield for energy conservation and emission reduction. As an important field for carbon reduction, the green transformation of cities is crucial for achieving the “dual carbon” goals. This article focuses on 48 cities in the three most mature and influential urban agglomerations in China from 2011 to 2019, namely, the Beijing-Tianjin-Hebei urban agglomeration, the Yangtze River Delta urban agglomeration, and the Pearl River Delta urban agglomeration. The three-stage DEA model and Malmquist index model are used to measure the green transformation efficiency of the three urban agglomerations from both dynamic and static perspectives, and a Tobit regression model is constructed to explore the influencing factors of green transformation efficiency in urban agglomerations. Research has found that: 1) From a static perspective, the overall efficiency of green transformation in the three major urban agglomerations is at a high level, but from a temporal perspective, it shows a downward trend. The Pearl River Delta urban agglomeration is known for its green development, with the highest average efficiency of green transformation, followed by the Yangtze River Delta urban agglomeration. The Beijing-Tianjin-Hebei urban agglomeration has the lowest level of green transformation; 2) From a dynamic perspective, technological progress is the main driving factor for improving the efficiency of green transformation in the three major urban agglomerations. Therefore, the government should pay special attention to the progressiveness of technology when formulating relevant policies to promote urban green transformation; 3) From the perspective of spatiotemporal differences, there are significant differences in the spatiotemporal characteristics of green transformation among the three major urban agglomerations, and there are significant differences in green transformation strategies among different urban agglomerations. Eliminating environmental factors and random interference is necessary for accurately measuring the efficiency of green transformation in urban agglomerations; 4) From the perspective of influencing factors, factors such as industrial structure upgrading, green innovation level, and environmental regulation intensity jointly affect the efficiency of green transformation in urban agglomerations. Based on this, we should pay attention to the differences between urban agglomerations and implement policies tailored to local conditions; Strengthen the network system of urban agglomerations and avoid conflicts between cities; Encourage green technology innovation, accelerate industrial structure upgrading, and so on. This article focuses on the issue of green transformation in urban agglomerations, and conducts research from three perspectives: efficiency measurement, influencing factors, and implementation mechanisms. A relatively systematic theoretical framework for green transformation in urban agglomerations is formed, and an evaluation index system for green transformation efficiency in urban agglomerations is constructed and optimized. The composition mechanism of the five dimensional evaluation system for transformation efficiency is analyzed, and the bottleneck and breakthrough direction of the three major urban agglomerations in China in the development process are grasped. It has a good demonstration effect on the green transformation of other urban agglomerations.

Phase Transformation of Arsenic, Antimony and Lead in High-Grade Copper Matte Converting

The duration of the high-grade matte converting process is short, the amount of slag is small, and it is difficult for the original impurity removal operation in the low-grade matte converting process to meet the current production demand. Because the removal method for impurity elements during high-grade matte converting is unclear, the phase transformation of impurity elements during this process is investigated in this study. The results show that arsenic exists mainly in the form of FeAsO4 and As2O5, antimony in the form of Sb and Sb2O5, and lead in the form of PbS and PbO in high-grade matte. During the converting process, arsenic and antimony mainly exist in the melt in the form of oxides and gradually aggregate into large particles with increasing copper content in the melt. Lead exists in matte in the form of PbS until the end of the converting process, and PbS is not completely oxidized until the matte converted to blister copper phase. The phase transformation characteristics of copper, iron, sulfur and impurity elements in the process of high-grade matte converting were revealed. This study provides a theoretical reference for the formulation of an efficient impurity removal scheme for the converting process.

Effects of Application of Different Organic Materials on Phosphorus Accumulation and Transformation in Vegetable Fields

Presently, the improvement of soil organic matter is the basis to ensure food security, but the accumulation and transformation characteristics of soil phosphorus (P) as affected by organic matter remain unclear. The accumulation, transformation, and migration characteristics of soil P in different soil layers of vegetable fields were researched under the application of organic materials. Six treatments were set up in the experiment:control (no fertilization), traditional fertilizer application by farmers, biochar, chicken manure, food waste, and straw application. Available phosphorus (Olsen-P), water-soluble phosphorus (CaCl2-P) content, soil phosphorus forms, soil organic matter (SOM), and pH were determined during the pepper harvest period. In the 0-5 cm and 5-10 cm soil layers, the available phosphorus content of traditional fertilization of farmers was higher, and the available phosphorus content of the four organic materials was in the order of straw > biochar > chicken manure > food waste. Compared to that with food waste, the straw and biochar treatments increased soil available phosphorus by 59.6%-67.3% and 29.1%-36.9%, respectively. The straw treatment could easily enhance the soil labile P pool, and soil labile P in the 0-5 cm soil layer increased by 47.3% and 35.1% compared with that under the chicken manure and food waste treatments, respectively. With the increase in soil depth, the proportion of available phosphorus in the chicken manure treatment decreased the least, and available phosphorus of the 20-30 cm soil layer accounted for 55.9% of the topsoil layer but only accounted for 16.0%-34.0% under treatment with the other three materials. Compared with that under the traditional fertilization of farmers, the pH significantly increased by 0.18-0.36 units after the application of organic fertilizer, and the pH of the chicken manure and food waste treatments was significantly higher than that of biochar and straw (P < 0.05). SOM content under the biochar treatment significantly increased by 7.7%-17.6% compared to that under the other three organic materials. Among the four organic materials, the straw treatment boosted the labile P pool the most, which was conducive to the rapid increase in plant-available P. Phosphorus was most likely to migrate downward under the chicken manure treatment. In the field management based on soil fertility enhancement, the application of biochar could not only improve soil pH and SOM but also avoid excessive accumulation of phosphorus in the surface layer, which decreases environmental risks.

Novel use of the electrocatalytic oxidation process with Fe-DSA dual anode configuration for leachate treatment: Significance of in situ ferrate generation

The leachate produced by waste transfer stations (WTSs) contains substantial amounts of refractory organic matter and ammonia, necessitating on-site treatment. In this study, a novel electrocatalytic oxidation (ECO) process with Fe-DSA dual anode configuration was established for leachate pretreatment. In this configuration, chloride in the leachate was converted to active chlorine by the DSA anode, while ferric hydroxide (Fe(OH)3) was produced from Fe anode. As a result, Fe (VI) was in situ formed through the reactions between active chlorine and Fe(OH)3. Simultaneous and efficient removal of COD and NH4+-N in the ECO process with Fe-DSA dual anode configuration was achieved, significantly improving leachate biodegradability compared with the Fe–Fe and DSA-DSA dual anode configurations. The transformation characteristics of organic compounds in the ECO process were investigated through the electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) analysis. The ECO process with Fe-DSA dual anode configuration promoted the removal and transformation of lignins/carboxylic rich alicyclic molecules (CRAM)-like and tannins compounds with biologically refractory properties, as well as S-containing compounds with biological toxicity. Further X-ray photoelectron spectroscopy (XPS) analysis revealed that iron oxides, amorphous Fe-(oxy) hydroxide, and amorphous Fe(OH)3 produced by Fe (VI) decomposition in the ECO process with Fe-DSA dual anode configuration enhanced removal performance through coagulation. In addition, the contribution of different active species to organic matter removal in the ECO process was quantified by quenching experiments. High-valent iron oxidation dominated the ECO process with Fe-DSA dual anode configuration, while active chlorine oxidation, •OH oxidation and coagulation synergistically contributed to organic matter removal.