Uniform Ratio Research Articles

On the coexistence of rift-related silica-undersaturated and silica-saturated alkaline rocks – The cretaceous Messum alkaline complex (Namibia) revisited

The ~132 Ma-old Messum igneous complex, a circular structure of ~18 km diameter, belongs to the Damaraland intrusive complexes that intruded into the Pan-African Damara basement of Namibia. The plutonic rocks of the core of the complex comprise olivine-gabbro, biotite-gabbro, nepheline-syenite and quartz-syenite as well as minor alkali gabbro and coexist with the Etendeka volcanic sequences of the Goboboseb Mountains, comprising basalts (Tafelkop and Tafelberg types) that are overlain by deposits of several quartz latite eruptions. New major and trace element and Sr, Nd and Pb isotope data are reported for nepheline-syenite and quartz-syenite. Major and trace element data are consistent with the development of nepheline-syenites through fractional crystallization processes. The nepheline-syenite samples have initial 87Sr/86Sr of 0.7046–0.7049 and initial εNd ranging from +0.53 to +1.47, indicating a mantle source with time-integrated lithophile element depletion. Initial Pb isotopes are rather uniform (206Pb/204Pb:17.89–18.14, 207Pb/204Pb: 15.56–15.58, 208Pb/204Pb: 37.78–38.00). Uniform initial Sr and Pb isotope ratios for nepheline-syenites suggest that the syenite magmas evolved through fractional crystallization from an inferred mafic alkaline magma without crustal contamination. However, the range in Nd isotope composition is too large to be related to crystal fractionation alone and imply a heterogeneous source with respect to the Nd isotope composition. The quartz-syenites show a large range in initial εNd (+1.0 to −4.4) and initial 87Sr/86Sr (0.7047–0.7115). Initial Pb isotope ratios are also heterogeneous (206Pb/204Pb: 18.29–18.74, 207Pb/204Pb: 15.60–15.65, 208Pb/204Pb: 37.43–38.49). These data, together with major and trace element constraints and results from AFC modeling substantiate the production of the quartz-syenites by fractional crystallization of clinopyroxene, amphibole and K-feldspar accompanied by assimilation of up to about 30 % pre-Pan African lower crust. Isotope and chemical data do not support derivation from a single batch of magma undergoing contamination, but suggest that a large magma body at depth evolved largely by fractionation with batches of melt extracted from this chamber being variably contaminated at lower crustal levels.

Fabrication of model ultrafiltration membranes with uniform, high aspect ratio pores

In this manuscript, we report the facile fabrication of large-area model membranes with highly uniform and high aspect ratio pores with diameters <20 nm. These membranes are useful for fundamental investigations of separation by size exclusion in the ultrafiltration regime, where species to be separated from solution have dimensions of 1–100 nm. Such investigations require membranes with narrow pores and high aspect ratios such that the Hagen–Poiseuille equation is followed, enabling well-known models such as the hindered transport model to be evaluated and other affecting factors to be ignored. We demonstrate that the sub-20 nm pores in the membrane are of sufficiently high aspect ratio such that water flux through the membrane is consistent with the Hagen–Poiseuille equation. The fabrication relies on self-assembling block copolymers to form uniform, densely packed patterns with sub-20 nm resolution, sequential infiltration synthesis to convert the block copolymer in situ into a mask with adequate contrast to etch pores with an aspect ratio >5, and low-resolution photolithography to transfer the pattern over a large area into a silicon nitride membrane. Model membranes with narrow pore-size distribution fabricated in this way provide the means to investigate parameters that impact size-selective ultrafiltration separations such as the relationships between solute or particle size and pore size, their distributions, and rejection profiles, and, therefore, test the validity or limits of separation models.

Chloroplast Genome Variation and Phylogenetic Relationships of Autochthonous Varieties of Vitis vinifera from the Don Valley.

The autochthonous grape varieties of the Don Valley, situated in southern Russia, constitute a distinctive element of regional cultural heritage. These varieties have been adapted over centuries to the region's specific local climatic and soil conditions. For the most part, these varieties are not imported from other countries. They are closely related to varieties found in Crimea and the North Caucasus. In this study, we obtained the first complete, unfragmented sequences of the chloroplast genomes of eight autochthonous varieties from the Don Valley and one from Crimea. We also performed a comparative analysis of their genomic features. The size of Vitis vinifera chloroplast genome sequences varied from 160,925 to 160,991 bp, depending on the cultivar, with a uniform GC ratio of 37.38%. Each genome consists of four subregions: a single copy region (LSC) ranging from 89,158 to 89,336 bp, a small single copy region (SSC) ranging from 19,070 to 19,073 bp, and a pair of inverted repeat regions (IRa and IRb) in the range of 26,292 to 26,353 bp. The chloroplast genomes of the studied V. vinifera varieties contained 130 genes, including 85 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. The sequence divergence analysis has enabled the identification of four highly variable regions, which may be utilized as potential markers for phylogenetic analysis. The analysis revealed the presence of 58 to 61 SSRs and multiple long repeated sequences in the chloroplast genomes of these varieties. The phylogenetic analyses of the sequences obtained and complete chloroplast genomes available from public databases indicated that the majority of autochthonous V. vinifera varieties do not have a direct origin from any European variety.

Explicit formulas for the asymptotic variance of a linearized model of a Gaussian disturbance driven power system with a uniform damping-inertia ratio

Serious fluctuations caused by disturbances may lead to instability of power systems. With the disturbance modeled by a Brownian motion process, the fluctuations are often described by the asymptotic variance at the invariant probability distribution of an associated Gaussian stochastic process. Here, we derive the explicit formula of the variance matrix for the system with a uniform damping-inertia ratio at all the nodes, which enables us to analyze the influences of the system parameters on the fluctuations and investigate the fluctuation propagation in the network. With application to systems with complete graphs and star graphs, it is found that the variance of the frequency at the disturbed node is significantly bigger than those at all the other nodes. It is also shown that adding new nodes may prevent the propagation of fluctuations from the disturbed node to all the others. Finally, it is proven theoretically that larger line capacities accelerate the propagation of the frequency fluctuation and larger inertia of synchronous machines help suppress the fluctuations of the phase differences, however, these acceleration and suppression are quite limited.

Effect of recycled fiber modified by CNTs-epoxy resin composite coating on mechanical properties of mortar

In this study, the wastes GFRP was mechanically crushed and recycled GFRP fibers with a uniform aspect ratio were obtained through vibration screening and water separation treatment. In light of the surface-based interfacial defects present in recycled GFRP fibers, an epoxy resin-based nanocomposite coating reinforced with carbon nanotubes (CNTs) was employed for interfacial modification. The chemical properties of the recycled GFRP fibers before and after modification were characterised by XRD, FTIR and DTA. The changes in alkali resistance, mechanical properties and microstructure of the recycled fibers before and after modification were investigated by Alkali resistance test, mechanical testing and Scanning Electron Microscopy (SEM). Results indicated that the improvement of the coating on the fibers mainly included, blocking the erosion of alkali ions on the surface of the fibers and improving the mechanical properties of the fibers, reduced the shrinkage, and water absorption, with the highest compressive and flexural strength of 59.60 MPa and 7.13 MPa, respectively. The surface roughness due to the presence of resin and CNTs prevents easy debonding of fibers from the mortar. This property promotes strong bonding of fibers with the mortar matrix resulting in more effective fiber performance and improved mortar strength while enabling fiber recycling.

Key Component Analysis of the Time Toxicity Interaction of Five Antibiotics to Q67.

Antibiotics are considered as persistent emerging contaminants. The phenomenon of mixed exposure to the environment is a common occurrence causing serious harm to human health and the environment. Therefore, we employed enrofloxacin (ENR), chlortetracycline (CTC), methotrexate (TMP), chloramphenicol (CMP), and erythromycin (ETM) in this study. Nine treatments were designed using the uniform design concentration ratio (UDCR) method to systematically determine the toxicity of individual contaminants and their mixtures on Vibrio qinghaiensis sp.-Q67 through the time-dependent microplate toxicity assay. The combinatorial index (CI) method and the dose reduction index (DRI) were used to analyze the toxic interactions of the mixtures and the magnitude of the contribution of each component to the toxic interactions. The results showed that the toxicities of ENR, CTC, TMR, CMP, and ETM and their mixtures were time-dependent, with toxic effects being enhanced except when exposure time was prolonged. The types of toxic interactions in the ENR-CTC-TMR-CMP-ETM mixtures were found to be correlated with the proportion of each component's concentration, where the proportion of the components exerted the most significant influence. Through DRI extrapolation, it was determined that the primary components of the mixture exhibited a pronounced dependency on time. Specifically, at the 4 h mark, TMP emerged as the predominant component, gradually giving way to ENR as time advanced. Upon analyzing the frequency of mixture interactions under specified effects, the additive effect appeared most frequently (66.6%), while the antagonist effect appeared the least frequently (15.9%) among the nine rays.

Numerical Simulation of Equal Ratio Relations for the Peak Intensities of >10 MeV Energetic Protons

Previous studies have highlighted the significance of perpendicular diffusion in the decay phase of particle intensities for >10 MeV energetic protons. Recently, an observational study has indicated that the peak intensity ratios across different energy channels (13−64 MeV protons) remain almost constant as the spacecraft location varies in many solar proton events. This interesting phenomenon is referred to as equal ratio relations. These findings suggest that perpendicular diffusion not only affects particle intensity during the decay phase but also throughout the rising phase. In this study, we perform numerical simulations of >10 MeV energetic proton events observed by STEREO A, STEREO B, and the Solar and Heliospheric Observatory. Our findings demonstrate that perpendicular diffusion strongly affects the entire time profile of particle intensity for spacecraft not magnetically connected to the source region. The numerical simulation results indicate that in order to reproduce observations, we need to include perpendicular diffusion near the source region and in interplanetary space. Perpendicular diffusion leads to nearly uniform peak ratios at different locations and contributes to the formation of the reservoir phenomenon during the decay phase. Consequently, these numerical results support the significant role of perpendicular diffusion in the formation of the longitudinal distribution of >10 MeV proton events.

Energy characteristics of multi-chiller load distribution algorithms in a large office building

This study evaluates the energy efficiency of multi-chiller systems in large office buildings, focusing on their optimization across various climate zones as defined by ASHRAE. Using EnergyPlus for simulations, the research examines five different load distribution algorithms in multi-chiller systems that range from one to ten chillers, aiming to understand their effectiveness in 15 distinct climate zones. The primary objectives of the study include identifying the energy efficiency of multi-chiller systems in each climate zone, determining the appropriate number of chillers for each zone, and evaluating the performance of the load distribution algorithms. Based on the U.S. Department of Energy’s commercial building model, the results suggest that multi-chiller systems can significantly reduce cooling energy consumption in various climates. Among the algorithms evaluated, the Sequential Uniform Part Load Ratio (SUPLR) algorithm demonstrates notable efficiency, especially in the 4A climate zone (Baltimore), where it achieves substantial energy savings. Applying the SUPLR algorithm in a multi-chiller setup with four chillers in this zone leads to an estimated 24.5 % reduction in energy usage, equivalent to 183 MW annually. The research indicates that a range of 3 to 5 chillers is typically optimal for most climate zones. In-depth analysis in the 4A climate zone highlights the importance of minimizing operation hours at low Part Load Ratios (PLR) to ensure that chillers operate at a high Coefficient of Performance (COP). This strategy underscores the potential of well-designed multi-chiller systems to reduce cooling energy demand, particularly in climates with transitional seasons. This study provides an overview of the energy-saving potential of multi-chiller systems, applicable across a variety of climatic scenarios.

Experimental and numerical investigations on formation mechanisms of hollow structures in overflow water‐assisted injection‐molded parts of short‐glass‐fiber‐reinforced polypropylene

AbstractIn water‐assisted injection molding processes, it is crucial to understand the mechanisms governing the formation of hollow structures and identify the key factors influencing their morphology and dimensional accuracy. This work combined experimental analysis and numerical simulation to investigate the influence of different mold cavities and main processing parameters on hollow structures in overflow water‐assisted injection molded parts of short‐glass‐fiber‐reinforced polypropylene, that is, hollow shape and hollow ratio. The results show that the hollow shape and hollow ratio depended not only on the cross‐sectional location but also on the cross‐sectional shape of the mold cavity. For the circular parts, the hollow shape resembled the cross‐sectional shape of the mold cavity, with a relatively small and uniform hollow ratio across cross‐sectional locations. For the noncircular parts, the hollow shape varied considerably with increasing distance from the water inlet. Moreover, the results also show that except for the influence of water‐injection delay time on the uniformity of the hollow ratio, higher melt temperature (250°C), shorter water‐injection delay time (0 s), and higher water pressure (10 MPa) contributed to the hollow shape being closer to the cross‐sectional shape of mold cavities and made hollow ratios relatively larger and more uniform.

Porous Organic Nanotubes: Chemistry of One-Dimensional Space.

ConspectusOne-dimensional organic nanotubes feature unique properties, such as confined chemical environments and transport channels, which are highly desirable for many applications. Advances in synthetic methods have enabled the creation of different types of organic nanotubes, including supramolecular, hydrogen-bonded, and carbon nanotube analogues. However, challenges associated with chemical and mechanical stability along with difficulties in controlling aspect ratios remain a significant bottleneck. The fascination with structured porous materials has paved the way for the emergence of reticular solids such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and organic cages. Reticular materials with tubular morphology promise architectural stability with the additional benefit of permeant porosity. Despite this, the current synthetic approaches to these reticular nanotubes focus more on structural design resulting in less reliable morphological uniformity. This Account, highlights the design motivation behind various classes of organic nanotubes, emphasizing their porous interior space. We explore the strategic assembly of organic nanotubes based on their bonding characteristics, from weak supramolecular to robust covalent interactions. Special attention is given to reticular nanotubes, which have gained prominence over the past two decades due to their distinctive micro and mesoporous structures. We examine the synergy of covalent and noncovalent interactions in constructing assembly of these nanotube structures.This Account furnishes a comprehensive overview of our efforts and advancements in developing porous covalent organic nanotubes (CONTs). We describe a general synthetic approach for creating robust imine-linked nanotubes based on the reticular chemistry principles. The use of spatially oriented tetratopic triptycene-based amine and linear ditopic aldehyde building blocks facilitates one-dimensional nanotube growth. The interplay between directional covalent bonds and solvophobic interactions is crucial for forming uniform, well-defined, and high aspect ratio nanotubes. The nanotubes derive their permeant porosity and thermal and chemical stability from their covalent architecture. We also highlight the adaptability of our synthetic methodology to guide the transformation of one-dimensional nanotubes to toroidal superstructures and two-dimensional thin fabrics. Such morphological transformation can be directed by tuning the reaction time or incorporating additional intermolecular interactions to control the intertwining behavior of individual nanotubes. The cohesion of covalent and noncovalent interactions in the tubular nanostructures manifests superior viscoelastic mechanical properties in the assembled CONT fabrics. We establish a strong correlation between structural framework design and nanostructures by translating reticular synthesis to morphological space and gaining insights into the assembly processes. We anticipate that the present Account will lay the foundation for exploring new designs and chemistry of organic nanotubes for many application platforms.

Deciphering sources of lode gold deposits in the South Tianshan, NW China: Insights from Pb isotope systematics

The Tianshan hosts numerous giant and world-class lode gold deposits, forming one of the world’s largest gold provinces. However, the sources of gold remain equivocal. Herein, we present a comprehensive Pb isotopic investigation of the Precambrian basement, Neoproterozoic mafic dykes, and the Lower Paleozoic sequences of the South Tianshan in NW China. These data were compared with existing Pb isotope datasets from major lode gold deposits and coeval granitoid and mantle-related rocks, to trace the sources of gold and constrain the relative contributions from potential reservoirs. Gold-bearing sulfides from major lode gold deposits have relatively uniform Pb isotopic ratios, which are significantly different from regional coeval granitoid and mantle-related rocks. Conversely, the Pb isotopic characteristics from gold-bearing sulfides are comparable to those from the Paleoproterozoic metasedimentary rocks, showing well-defined linear relations. Binary mixing modeling shows that the Paleoproterozoic metasedimentary rocks might have contributed 70% to 90% for the source of Pb and, by inference other metals. Integrating geochemical and isotopic features from major lode gold deposits in the region, we propose that it invokes fertilization of ancient Au archives during metamorphic volatilization in the deep crust during subduction of the South Tianshan Ocean. Following the final closure of the South Tianshan Ocean, the regional tectonic uplift and thermal effect during widespread granitoids emplacement associated with the amalgamation of the Tarim with Kazakhstan-Yili terranes, mobilizing the deep roots of the fertilized ancient Au reservoirs, leading to the formation of the gold deposit hosted in fault systems of the South Tianshan.

Fast Prediction and Optimization of Building Wind Environment Using CFD and Deep Learning Method

CFD offers advantages over wind tunnel experiments in the prediction and optimization of building wind environment; however, the computational costs associated with optimizing architectural wind environment remain a challenge. In this study, an approach that combines deep learning techniques with CFD simulations is proposed for the prediction and optimization of the architectural wind environment efficiently. A dataset of wind field is constructed using CFD simulation, considering various wind directions, wind speeds, and building spacing. Subsequently, a U-net deep learning model is trained as a surrogate model to rapidly predict the architectural wind field under different conditions. The results indicate that the model can accurately predict the wind field in buildings. The prediction time of building wind field is only 1/900 of that of CFD simulations, making it a viable surrogate model for wind environment optimization. Furthermore, considering all the building layouts and inflow conditions examined in this study, the maximum and minimum uniform wind speed area ratios Auni are 0.84 and 0.13, respectively. Under a single inflow speed, the maximum improvement in the Auni is 0.4, with an improvement rate of 48%. The results demonstrate the effectiveness of the proposed method as an efficient approach for optimizing architectural wind environment.

Investigations of fatigue crack growth rate behaviour and life prediction of Si3N4/TiB2 reinforced hybrid metal matrix composites

Many engineering structures and components experience complex fatigue loading throughout their operational lifespan. Economically, it is crucial to forecast the remaining lifespan to prevent catastrophic failure by implementing appropriate inspection schedules. The aim of present work is to investigate the fatigue, and fracture performances of AA7075 alloy-based hybrid MMCs containing Si3N4/TiB2 reinforcement. The composite samples are made by a liquid-state stir-casting process. The study examines the fatigue characteristics of manufactured Hybrid Metal Matrix Composites (HMMCs) by analyzing fatigue crack propagation and fracture toughness under constant amplitude loading with a uniform load ratio of 0.1. The potential influence of reinforcement particles on the fatigue durability of HMMCs was predicted through the application of an 'Exponential Model'. A comparison between the model's performance and experimental findings is carried out. The study suggests that the exponential model accurately predicts fatigue life, showing a maximum percentage deviation of −4.96 %, in close agreement with experimental findings. The fatigue crack growth rate (da/dN) and crack opening displacement (COD) of HMMC indicate that the fatigue life and fracture toughness improve with increase in TiB2 content, up to 6 wt.%. The fabricated HMMC with 4 wt.% Si3N4 and 6 wt.% TiB2 particulates demonstrated the highest resistance to fracture and longest fatigue life among others HMMCs and base alloy.

Ultrafast-laser-inscribed multiscan type-I mid-infrared waveguides and beamsplitters in IG2.

This study reports the fabrication and characterization of various configurations of mid-infrared waveguides and beamsplitters within the chalcogenide glass IG2 using ultrafast laser inscription (ULI). Our investigation reveals two distinct regimes of ULI modification: weak and strong. The strong regime, marked by higher pulse energies, presents darker and prominent waveguide morphology, enabling efficient light guiding at 4.55 µm, but with higher scattering losses at shorter wavelengths. In the weak regime, we observed a significant enhancement in the mode confinement and a reduction in the propagation loss within the multilayer structures. We have investigated key geometric and inscription parameters such as inscription pulse energy and number of layers, as well as arm separation and splitting angles for beamsplitters. We have successfully fabricated beamsplitters with configurations ranging from 1 × 2 to 1 × 8, achieving a uniform splitting ratio over 96% and a splitting loss as low as 0.4 dB at 4.55 µm. These findings highlight the significant potential of ULI-based IG2 waveguides and beamsplitters for mid-infrared photonics.

Investigation of Wear Rate of Passenger Airplanes Tyres During Landing

A real, functioning copy of one main landing gear wheel is used to show the landing impact of an aircraft. By minimizing abrasive sliding between aircraft tires and runway surfaces right after touchdown, this study seeks to identify possible tire-life improvements. An experimental investigation of size 22 X 5.5, type VII airplane tyres was conducted to evaluate the wear and related properties of temperature and friction caused while braking. One way to evaluate the tire's performance on surfaces with uniform slip ratios, including asphalt, concrete, and slurry seal, was to gear it up to the driving wheel of a ground vehicle. The range of slip ratios often attributed to an airplane's braking system was covered by the data gathered during dry runway operations. Our results show that cumulative tire wear is affected by runway surface features, increases with increasing slip ratio, and changes linearly with miles. The differing wear rates associated with the various surfaces may be used to rank runways based on tire wear.

Uniform deformation distribution of structures at different seismic hazard levels using endurance time method

This paper evaluates the application of the endurance time method in the optimum performance design of structures using the uniform deformation theory. The structures used in this study include shear-building systems with 5, 10, and 15 stories, and steel moment-resisting frames with 3, 7, and 12 stories. Initially, shear-building systems are optimized to have uniform story ductility ratios at low, moderate and high seismic hazard levels separately using three sets of ground motion records and a compatible series of endurance time acceleration functions. The effectiveness and accuracy of the endurance time method are assessed by comparing lateral force distribution obtained from this method with its corresponding attained from ground motion records. Moreover, as the number of stories and target ductility increases, the compatibility of these two methods improves. However, it is found that the optimum structure at one seismic hazard level does not necessarily lead to the optimum structure at other seismic hazard levels. Next, by adding dampers with gap to the systems, a procedure is suggested to optimize these structures at different seismic hazard levels simultaneously. These dampers are activated at moderate and high seismic hazard levels. Finally, similar optimization algorithm is used for steel moment-resisting frames to make their story drift ratios or plastic hinge rotations uniform along the height at different seismic hazard levels. Results show that combining endurance time method and uniform deformation theory leads to a promising optimization procedure that can significantly reduce computational costs with reasonable error.

Direct shear test study on old and new concrete

The interface between new and old concrete is a common feature in prefabricated concrete structures and structural reinforcement. Its shear-slip performance directly impacts the stress performance and deformation capacity of members and structures. This paper aims to examine the influence of roughness density, roughness, roughness treatment, and rebar distribution on the shear performance of the interface by conducting direct shear tests on 14 Z-type specimens without dowel bars and 10 Z-type specimens with dowel bars. The tests reveal that specimens without dowel bars fail in shear brittle, with the roughness density of the interface having the most significant impact on shear strength, followed by roughness, and a minimal effect from the roughness treatment method. In contrast, specimens with dowel bars exhibit shear ductile damage. An increase in the number of inserted bars at a uniform reinforcement ratio leads to increased bond stiffness and shear strength, and a decrease in peak slip. The interface after rough chiseling exhibits the highest shear strength, followed by the interface after broaching, and the interface after grooving has the lowest shear strength. Increasing the roughness or designing dowel bars can enhance the strain coordination ability of the structure, which is beneficial for overall stress loading. Finally, finite element analysis was used to validate the reliability of the tests. Refined modeling of the grooved model without dowel bars revealed that peak height correlates best with shear strength, and that chiseling and other methods of improving the valley depth of the concrete interface at the base level are still superior roughness treatments.

X-Cut Lithium Niobate Optical Waveguide with High-Index Contrast and Low Loss Fabricated by Vapor Proton Exchange

Highly integrated and stable devices are appealing in optical communication and sensing. This appeal arises from the presence of high refractive index contrast and high-quality waveguides. In this study, we improved the vapor proton exchange (VPE) process, enabling large-scale waveguide fabrication and addressing the issue of liquid exchange during cooling. Additionally, we have prepared and characterized planar waveguides on X-cut lithium niobate (LN) crystals. The exchanged samples exhibit α and k1 phases, refractive index contrasts as high as 0.082, and exceptional refractive index uniformity. Furthermore, we utilized the same process to fabricate channel waveguides and Y-branch waveguides. We achieved low propagation losses in channel waveguides, accompanied by small mode sizes, and low-loss Y-branch waveguides with a highly uniform beam splitting ratio. All waveguides exhibited consistent performance across multiple preparations and tests, remaining free from aging effects for three months. Our results underscore the promising potential of VPE for creating Y-branch splitters and modulators in LN crystals.

Influence mechanism of the three-zone synergistic efficiency-enhancing pattern on the 3D flow field and thermal resistance characteristics for wet cooling towers

For a super-large natural draft wet cooling tower (S-NDWCT) equipped in a 1000 MW unit, a 3D numerical model of the three-zone synergistic efficiency-enhancing pattern (TSEP) was established and validated. This study focused on the influence mechanism of the three-zone parameters on the 3D flow field and thermal resistance characteristics, including the installation height h, installation angle θ, total coverage area S, length L and number n of the split-flow plate, water distribution partition radius R1, the proportion of inner zone water amount P, and fillings partition radius R2. The results showed that the TSEP reconfigures and comprehensively optimizes the airflow field, and presents the more uniform air-water ratio and water temperature fields. The volumetric heat transfer coefficient hv increases and then reduces as h, θ, S, n, R1, P and R2 increase, and increases continuously with increasing L in the range studied. Additionally, the ventilation G increases and then reduces with the increase of h, θ, R1 and P, increases with rising S, n and R2, and reduces with L increases. Finally, the relatively optimized values of the three-zone parameters are obtained. In this case, compared with a conventional tower, the hv and G increase by 11.3% and 10.6%, respectively.

Effect of coiling temperature on the microstructure and mechanical properties of DP 980 steel

The effect of coiling temperature on the microstructure and mechanical properties of annealed dual phase steels was investigated. It was found that the rate of ferrite recrystallization with coiling temperature 550°C is faster than that with coiling temperature 650°C. That is low coiling temperature accelerates the recrystallization of ferrite during heating compared with high coiling temperature, which in turn promotes the formation of austenite through the nucleation process. Under the same annealing conditions, the martensite content of annealed steels obtained at low temperature coiling 550°C is higher than that of annealed steels obtained at high coiling temperature 650°C. Compared with high coiling temperature, the low coiling temperature favors the formation of the homogeneous and fine microstructure. Thus, the dual phase steel obtained at low coiling temperature has finer and uniform microstructure and high hole expansion ratio at annealing temperature 800°C in comparision with the dual phase steel obtained at high coiling temperature.