Publications

Effects of steel chips on the microstructure, mechanical property, and durability of ultra-high-performance concrete with high elastic modulus

Although ultra-high-performance concrete (UHPC) performs well in terms of strength and durability properties, it is still limited by the low elastic modulus. To overcome this limitation, for the first time, a system investigation was carried out to validate the feasibility of producing UHPC with high elastic modulus (HEMUHPC) by using steel chips (SC) and alumina micro-powder. The initial mixture of HEMUHPC was designed via modified Andreasen and Andersen particle packing model, and the effects of different contents of steel chips on the workability, mechanical properties and durability of HEMUHPC were systematically investigated. Besides, the influence of SC on the microstructure of HEMUHPC was also studied. It was found that, 1) the flexural strength, compressive strength, and elastic modulus of HEMUHPC were increased by 15.49%, 18.33%, and 18.84%, respectively, when the SC content was 50 wt%; 2) when the steel chips content was 50 wt%, the chloride migration coefficient of HEMUHPC was reduced by 12.22%; 3) appropriate amount of SC could lead to a reduction in the porosity and threshold pore diameter of HEMUHPC; 4) the optimal content of SC in HEMUHPC was 50 wt%, considering the effects of SC on the mechanical properties, microstructure, and durability.

Sustainable seawater-sea sand cement mortar with municipal solid waste incineration ash: Mechanical performance, microstructure, and environmental benefits

Mechanical properties and microstructure of ultra-high-performance concrete with high elastic modulus

Elastic modulus is an important parameter in engineering structural design for evaluating the stiffness of concrete members. Ultra-high-performance concrete (UHPC) has excellent mechanical properties and durability, but the relatively low elastic modulus prohibits the widespread use of the UHPC. In this study, high elastic modulus UHPC (HEMUHPC) was designed according to Modified Andreasen and Andersen particle packing model proposed by Funk and Dinger. Effects of alumina micro-powder (the content of alumina is higher than 99%, and the particle size is lower than 100 μ m ) on the workability, microstructure, and mechanical properties of HEMUHPC were systematically investigated. The reason for the improvement of elastic modulus of HEMUHPC was revealed by nano indentation test. It was found that, 1) the porosity and threshold pore diameter of HEMUHPC were reduced because of the addition of alumina micro-powder; 2) the flexural strength, compressive strength, and elastic modulus of HEMUHPC were increased by 3.54–11.23%, 8.89–22.83%, and 6.19–16.37%, respectively, due to the addition of alumina micro-powder; 3) the optimal content of alumina micro-powder was 10%, considering its effects on the workability, mechanical properties, and microstructure of HEMUHPC; 4) Nano indentation experiments showed that the elastic modulus of the alumina micro-powder was 90–135 GPa, which is much higher than the elastic modulus of hydration products of HEMUHPC, and thus the elastic modulus of the HEMUHPC matrix could be improved, due to the addition of alumina micro-powder.

Efficient all solid-state continuous-wave orange laser at 598 nm

We report for the first time a continuous-wave (CW) orange radiation at 598 nm by intracavity sum-frequency generation of 1341 nm Nd:GdVO4 laser and 1080 nm Nd:YAlO3 (Nd:YAP) laser. Orange laser is obtained by using a doubly cavity, type-II critical phase matching KTP crystal sum-frequency mixing. With total pump power of 36 W, TEM00 mode orange laser at 598 nm of 268 mW is obtained. The orange power stability in 30 min is better than 3.8%.

Optimizing ecological ultra-high performance concrete prepared with incineration bottom ash: Utilization of Al2O3 micro powder for improved mechanical properties and durability

Within the domain of municipal solid waste (MSW) management, incineration is recognized as an efficient volume reduction method, yet it produces substantial quantities of bottom ash (IBA). Redirecting IBA into cementitious frameworks is challenging due to diminished workability, mechanical properties, and durability. This study investigates alumina micro powder (ALMP)'s effect on improving the mechanical and durability aspects of ecological ultra-high performance concrete (EUHPC) produced with IBA. The research examines ALMP's role at various doping levels on the EUHPC's rheological properties, mechanical strengths, durability indices, ultrasonic pulse velocity (UPV), and elastic modulus. Additionally, nanoindentation tests discern ALMP's reinforcing effect on EUHPC's stiffness. Summarizing key findings: ALMP significantly enhances EUHPC's flexural and compressive strengths, with increases ranging from 6.98 % to 24.87 % and 12.39–20.81 %, respectively. Moreover, ALMP raises the elastic modulus by 6.05–19.07% and UPV by 3.11–7.18 %, reflecting a denser, more compact matrix structure. Durability enhancements are evidenced by reductions in drying shrinkage by 4.41–20.01 % and decreased chloride migration by 7.01–22.14 %. Nanoindentation reveals a densification in the microstructure, with escalated high-density C-S-H phases and reduced low-density C-S-H and unhydrated materials. IBA replacement yields energy savings of 11.43 %, CO2 emission reduction of 7.01 %, and cost savings of 1.18 %. The optimal ALMP inclusion is identified at 10 %, balancing workability, mechanical and microstructural benefits in EUHPC. These revelations position IBA as a useful component in the concrete sector and advocate for ALMP as a beneficial adjunct to elevate the performance of IBA-based concrete towards sustainable development goals.

Synthesis and Performance Evaluation of Anti-Washout Admixtures for Underwater Non-Dispersive Concrete Based on Nanosilica

Anti-washout admixtures (AWAs) are a unique component of underwater non-dispersive concrete (UNDC), which gives the concrete the ability to remain undispersed in water. On some special occasions, freshly mixed underwater non-dispersive concrete is exposed to the erosion of moving water, and conventional acrylamide-based AWAs are only suitable for static water or the water flow rate is small. In this study, the inorganic component nanosilica (NS) is modified, treated, and copolymerized with the organic components acrylamide (AM) and acrylic acid (AA) to form an inorganic–organic hybrid polymer with a hyperbranched structure, which changes the linear structure of the original polyacrylamide molecule, and we optimize the synthesis process. The polymers are characterized at the microscopic level and their compatibility with polycarboxylic acid water-reducing agents (SP) is investigated. In addition, the polymers are compared and evaluated with commonly used PAM in terms of their working performance. The experimental results indicated that under specific process conditions, polymers endow cement mortar with good resistance to water erosion. At the same time, the polymers’ three-dimensional network structure is prominent, with good compatibility with SP and better anti-dispersity. The microstructure of the cement paste with added polymers is dense and flat, but its flowability and setting time are slightly worse. This study provides a new development direction for the development of AWAs under a dynamic water environment, which has specific engineering significance.

Analysis and Design for Nonlinear Networked Control Systems with Interval Time-Varying Delay

This paper mainly concerns with the analysis and design for a class of nonlinear networked control systems (NCSs), which can be represented by a T-S fuzzy model with interval time-varying network delay. By using the convexity of the matrix function, the conservatism caused by enlarging¿ (t) to ¿M can be avoided. The controller parameters that guarantee the asymptotical stability and the performance of the closed-loop system are obtained by solving a set of linear matrix inequalities (LMIs). A numerical example is provided to show the effectiveness of the proposed method.

Effect of Inhibitor on Adsorption Behavior and Mechanism of Micro-Zone Corrosion on Carbon Steel

A new type of inhibitor is studied in this paper. Inhibition efficiency and adsorption behavior of an inhibitor film on the steel surface is tested via the electrochemical method and theoretical calculation to establish the adsorption model. Test results confirm that inhibition efficiency is improved with the addition of an inhibitor, and the inhibitor film is formed firmly by comparing the characteristic peaks of S and N. Moreover, the micro-zone corrosion progress of Fe in 3.5% invasive NaCl-simulated seawater environment is studied. The results further show that corrosion is initiated under the zone without the inhibitor film, while it is prevented under the protection of the film. By the experiments, it is shown that inhibitor can be adsorbed on the surface of steel stably and has excellent protection performance for reinforced rebar, which can be widely used in concrete structure.

Acceleration Velocity Trajectory Optimization of Intelligent EVs Using Battery Life Model

In this paper, taking an intelligent electric vehicle as the research object, mathematical models are firstly built for calculating the percentage of lithium-ion battery capacity loss and the internal resistance increase. Based on the model established, a control-oriented battery life model is derived using to calculate the battery capacity loss during an acceleration process. Then, a velocity trajectory optimization framework is presented to minimize the battery aging life for intelligent EVs during an acceleration process and the problem is solved by SQP algorithm. Finally, according to the simulation results, it can be concluded that the energy consumption per meter is 5.50kJ/m from 0 to 100km/h within 10s. The effect on battery capacity is much greater than that on battery internal resistance during the acceleration process.

Torque allocation of four-wheel drive EVs considering tire slip energy

With the increasing peak torque of the in-wheel motor, the tire slip energy dissipation becomes as considerable as the motor energy loss. The actuation red

Effects of graphene sulfonate nanosheets on mechanical and thermal properties of sacrificial concrete during high temperature exposure

Using nanomaterials is a new method to improve concrete material, and graphene or its derivatives are currently the most attractive nanomaterials. This paper aims to experimentally evaluate the effects of graphene sulfonate nanosheets (GSNSs) on physical, mechanical, and thermal properties of sacrificial concrete. The microstructure, porosity, compressive strength, thermal analysis, coefficient of thermal expansion, thermal diffusivity and ablation behaviour of sacrificial concrete with different contents of GSNSs before and during exposure to various temperatures up to 1000 °C were comprehensively investigated. A new experimental apparatus was proposed and used to measure the compressive strength of sacrificial concrete during elevated temperature exposure. It was found that, (1) the compressive strength, thermal diffusivity, and decomposition enthalpy of sacrificial concrete increased by 10.14–23.11%, 6.51–27.66%, and 7.48%, respectively, when adding 0.1 wt% GSNSs; (2) the porosity and ablation velocity of sacrificial concrete reduced by 2.00–6.00% and 7.48%, respectively, due to the incorporation of GSNSs.

Diode-pumped Nd:GAGG-LBO laser at 531 nm

We report a green laser at 531 nm generation by intracavity frequency doubling of a continuous wave (cw) laser operation of a 1062 nm Nd:GAGG laser under in-band diode pumping at 808 nm. A LiB3O5 (LBO) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 18.5 W, as high as 933 mW of cw output power at 531 nm is achieved. The fluctuation of the green output power was better than 3.5% in the given 4 h.

Adaptive Fuzzy Control for Ink Key of Offset Printing Machine

This paper analyzes the defect of some methods for controlling the ink key of offset printing machine, and presents the advantage of adaptive fuzzy control. Aiming at the problem that the processing curve of offset printing is changed by the environmental impact of production, this paper analyzes this non-real-time measurement and control system with time delay and less test data, and proposes the method of adaptive fuzzy control to amend the control table and adjust the slope of the control curve according to the detection deviations. Finally, the control rules are adjusted to meet the actual situation. By simulating the control arithmetic with the example of the control of printing ink keys under specific conditions using Matlab / Simulink, it is proved to be effective to achieve the expectative effect.

The experimental study on the correlation of resistivity and damage for conductive concrete

This paper investigates the correlation of conductivity and damage evolution in carbon fiber reinforced conductive concrete. Under axial static loading and quasi-static cycle loading, the damage evolution is detected by ultrasonic technique, and the variation of resistivity is also inspected using real-time measurement method. According to the stress wave theory, the relationship between the damage evolution in concrete and variation of ultrasonic velocity is obtained, eventually concluding in the correlation of concrete damage and its resistivity. The research results indicate that concrete real-time damage and resistivity exhibits cubic polynomial correlation under the condition of a static load, and concrete resistivity and residual damage shows exponential growth rule under the condition of a cyclic load.

Sustainable solidification and resource recovery: Utilizing municipal solid waste incineration fly ash in ecological mortar with reduced carbon footprint

Processing Variables of Alumina Slips and Their Effects on the Density and Grain Size of the Sintered Sample

High densities and small grain size of alumina ceramic bodies provide high strength and better mechanical properties than lower density and larger grain size bodies. The final sintered density and grain size of slip-cast, alumina samples depends greatly on the processing of the slip and the alumina powder, as well as the sintering schedule. There were many different variables explored that include initial powder particle size, slurry solids percent, amount and type of dispersant used, amount and type of binder used, and sintering schedule. Although the experimentation is not complete, to this point the sample with the highest density and smallest grain size has been a SM8/Nano mixture with Darvan C as the dispersant and Polyvinyl Alcohol (PVA) as the binder, with a solids loading of 70 wt% and a 1500 C for 2 hours sintering schedule. The resultant density was 98.81% of theoretical and the average grain size was approximately 2.5 {micro}m.

Mechanical Properties and Environmental Evaluation of Ultra-High-Performance Concrete with Aeolian Sand

Ultra-high-performance concrete (UHPC) has received increasing attention in recent years due to its remarkable ductility, durability, and mechanical properties. However, the manufacture of UHPC can cause serious environmental issues. This work addresses the feasibility of using aeolian sand to produce UHPC, and the mix design, environmental impact, and mechanical characterization of UHPC are investigated. We designed the mix proportions of the UHPC according to the modified Andreasen and Andersen particle packing model. We studied the workability, microstructure, porosity, mechanical performance, and environmental impact of UHPC with three different water/binder ratios. The following findings were noted: (1) the compressive strength, flexural strength, and Young’s modulus of the designed UHPC samples were in the ranges of 163.9–207.0 MPa, 18.0–32.2 MPa, and 49.3–58.9 GPa, respectively; (2) the compressive strength, flexural strength, and Young’s modulus of the UHPC increased with a decrease in water/binder ratio and an increase in the steel fibre content; (3) the compressive strength–Young’s modulus correlation of the UHPC could be described by an exponential formula; (4) the environmental impact of UHPC can be improved by decreasing its water/binder ratio. These findings suggest that it is possible to use aeolian sand to manufacture UHPC, and this study promotes the application of aeolian sand for this purpose.

Assessing the performance and sustainability of ecological mortar with municipal solid waste incineration fly ash solidified by sulphoaluminate cement

Municipal Solid Waste Incineration Fly Ash (MSWI-FA) contains heavy metals, dioxins, and hazardous substances, making it a hazardous waste. The application of solidification/stabilization (S/S) treatment using chelating agents is widespread due to its high efficiency. However, this treatment is associated with high solidification costs. In this study, an attempt was made to solidify MSWI-FA using sulphoaluminate cement (SAC). Firstly, the effects of varying substitution rates of MSWI-FA on the workability, mechanical properties, durability and heat of hydration of ecological cement mortar (EM) were investigated. Secondly, the microstructure of the EM was investigated in order to ascertain the mechanism of solidification of the MSWI-FA via the SAC. Finally, the economic and environmental benefits of MSWI-FA as an alternative to SAC for the production of EM were evaluated using the material sustainability index. Results show that adding MSWI-FA decreases EM’s workability and mechanical properties, with compressive and flexural strength reductions between 6.87 % and 26.16 % and 5.74–36.74 %, respectively. Durability also declines, evidenced by increased drying shrinkage and chloride migration by 26.79–46.41 % and 11.05–48.19 %, respectively. A slower hydration rate reduces the total heat of hydration by 1.82–7.22 %, indicating lower cement hydration. The porosity and pore size increase, deteriorating the pore structure. However, SAC effectively solidifies heavy metals, with leaching rates for lead and zinc significantly below national standards. A 15 % substitution rate of MSWI-FA reduces energy consumption, carbon emissions, and production costs by 14.90 %, 14.63 %, and 4.03 %, respectively, demonstrating notable economic and environmental advantages.