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To date, incineration is the main method of municipal solid waste (MSW) disposal. Fly ash and bottom ash (BA) are generated in large amounts from municipal solid waste incineration (MSWI), but the disposal of incineration residues poses a significant challenge to large cities with limited landfill space. The feasibility of using MSWI-BA to replace natural sand in the preparation of self-compacting mortar (SCM) was investigated to realize the resource utilization of MSWI-BA. The changes in SCM regarding durability, mechanical properties and workability when MSWI-BA was added at varying ratios were explored in this study. In addition, the changes in SCM microstructure, dynamic modulus of elasticity (DME) and ultrasonic pulse velocity (UPV) under the impacts of MSWI-BA were investigated. Eventually, the environmental and economic effects of SCM were weighed via the material sustainability index. It was found that (1) there was a drop of 23.79–44.69% in the compressive strength of SCM and a drop of 12.22–30.99% in the flexural strength, due to the incorporation of MSWI-BA; (2) the drying shrinkage of SCM increased from 2.9 to 11.76%, and the chloride migration coefficient increased from 4.66 to 46.06%, due to the incorporation of MSWI-BA; (3) the production costs, carbon footprint and energy consumption of SCM could be reduced, due to the addition of MSWI-BA; and (4) SCM could satisfy the engineering requirements of durability, mechanical properties and workability. Therefore, MSWI-BA was found to be a feasible method for the production of SCM. [ABSTRACT FROM AUTHOR]

Machining time and energy consumption are common process planning evaluation metrics. However, it is difficult to obtain accurate machining time and energy consumption values in the process planning stage, which may result in non-optimal obtaining process routes. To solve these problems, this paper proposes a flexible process planning method based on processing time and energy consumption prediction models. The historical processing data is analyzed, and a prediction model of machining time and energy consumption based on a radial basis function neural network is proposed. Considering the flexibility of multiple processes, a mathematical model of the flexible process planning problem based on the machining time and energy consumption prediction model is established. A multi-objective algorithm using a multidimensional real number coding method is proposed for problem-solving with the completion time and energy consumption minimization as the optimization objective. Two algorithms with better multi-objective optimization performance, the strength Pareto evolution algorithm 2, and the dominance ranking genetic algorithm II are selected for comparative analysis to obtain a better effect of optimization. The better algorithm is selected with the best parameters. Finally, case studies are conducted to verify the validity of the prediction model and the flexible process planning model. [ABSTRACT FROM AUTHOR]

Ultra-high-performance concrete (UHPC) has attracted wide interests in civil engineering but it has large deadweight, which limits its application in lightweight structures and rehabilitation. Compromising the merits of UHPC and lightweight concrete, ultra-high-performance lightweight concrete (UHPLC) is a potential solution to solve the drawback of high self-weight. Based on particle densely packing theory, this study proposed a UHPLC manufacturing approach using shale ceramic sand and air-entraining agent (AEA). An experimental study was conducted to systematically examine the effects of the types and contents of AEA on various performances of UHPLC, including its workability, mechanical properties, durability and microstructure. The results show the following: (1) The addition of AEA resulted in the decrease of UHPLC in elastic modulus, compressive strength and flexural strength but bring UHPLC higher specific strength; (2) A void system that is featured with homogeneous distribution of pores and an appropriate size and could be formed by adding a suitable amount of AEA; (3) The optimum proportion of AEA in UHPLC was 0.01% in consideration of its influence on UHPLC from the perspectives of microstructure, durability and mechanical properties. [ABSTRACT FROM AUTHOR]

Ink transfer is achieved by the squeezing and rotation of two rollers, one of which is a roller coated with a viscoelastic rubber layer. In this study, the force caused by ink hydrodynamic pressure on the rubber roller during the rotation is considered, the viscoelasticity of ink and rubber is equivalently substituted by spring-damping unit, and a rolling squeezing theoretical model of two rollers is established to study the node deformation of the rubber roller. The validity of the theoretical model is verified by experiments. Results show that the deformation of the rubber roller is greatly affected by the roller rotational speed, rubber layer thickness, and nip width. The rotational speed and nip width have a significant influence on the stiffness-damping of the ink layer and the ink force, and the rubber layer thickness has a remarkable effect on the squeezing deformation between the rollers. [ABSTRACT FROM AUTHOR]

Ultra-high-performance concrete (UHPC) has promising applications in civil engineering. However, the elastic modulus of UHPC is relatively low compared with its compressive strength, which may result in insufficient stiffness in service. This work was carried out to explore the feasibility of producing UHPC with high elastic modulus by nano-Al2O3 (NA). Based on particle densely packing theory, the initial mixture of UHPC was designed via the modified Andreasen and Andersen model. An experimental investigation was conducted to systematically examine the effects of NA on different properties of UHPC, including its fluidity, mechanical properties, durability, and microstructure. It was found that: (1) Compared with UHPC without NA, the flexural strength, compressive strength, and elastic modulus of UHPC were improved by 7.38–16.87%, 4.08–20.58%, and 2.89–14.08%, respectively, because of the incorporation of NA; (2) the addition of NA had a prohibiting impact on the threshold pore diameter and porosity of UHPC, which suggested that NA could be conducive to its pore structure; (3) the incorporation of NA led to a decline of 2.9–11.76% in the dry shrinkage of UHPC, which suggested that incorporating NA in a proper amount could reduce the risk of cracking and alleviate the dry shrinkage of UHPC; (4) the optimal amount of NA in UHPC was 1.0%, considering the effects of NA on workability, mechanical properties, microstructure, and the durability of UHPC. [ABSTRACT FROM AUTHOR]

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 %, CO 2 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. • Mixture of eco-UHPC was designed via MAA particle packing model. • Properties of eco-UHPC were improved via Al 2 O 3 micro-powder. • Optimal content of Al 2 O 3 micro-powder in eco-UHPC was 10%. • Al 2 O 3 micro-powder contributed to a denser microstructure of eco-UHPC. • Environmental friendliness of eco-UHPC was improved via Al 2 O 3 micro-powder. [ABSTRACT FROM AUTHOR]

For the flat plastic parts with the size range of 200 to 1300 mm, the structural parameters decision model of injection mold gating system is established in this paper. Firstly, the relationship between the warpage and the structural parameters of gating system is fitted by Kriging model, and the minimum warpage is optimized by genetic algorithm (GA) to obtain the best structural parameters. Secondly, the best structural parameters of gating system corresponding to 16 groups of plastic parts are taken as samples, and the relationship between the structural parameters of gating system and the size parameters of plastic parts is established by Kriging model. In addition, K-means is used to reduce the number of the structural parameters of gating system from 5 to 2, in order to improve the accuracy of decision model. Finally, the size parameters of plastic parts are input to the decision model to obtain the structural parameters of gating system. Through the verification of mold flow analysis experiment, the structural parameters of gating system obtained by this method meet the design requirements and can effectively shorten the structural design cycle of injection mold. [ABSTRACT FROM AUTHOR]

In order to improve the printing quality, this study focused on the thermo-fluid-solid coupling process of ink roller-ink. One of the highlights of this study is to consider the influence of temperature on the rubber hyperelastic parameters, viscoelastic parameters, and ink viscosity. The other highlight is to improve the elastohydrodynamic lubrication theory and Hertz contact theory through the rubber elastic modulus, which is determined by the relaxation curve considering the temperature and working conditions. Furthermore, based on the improved theory, the thermo-fluid-solid coupling model of ink roller-ink was established. Finally, the effect of temperature on the coupling process was analyzed. The results show that under the working conditions, with increasing temperature from 20 °C to 40 °C, the contact half-width increases from 4.2335 mm to 4.4701 mm, and the minimum ink film thickness decreases from 0.5097 mm to 0.1410 mm, and the maximum ink pressure decreases from 0.6802 MPa to 0.6618 MPa. [ABSTRACT FROM AUTHOR]

This paper studies the global stabilization problem for a class of uncertain time-delay nonlinear systems by designing a sampled-data output feedback controller via network. Under a lower triangular linear growth condition, when only the output is measurable, a sampled-data output feedback network controller, whose observer and control law are both linear, is constructed to solve the stabilization problem. Using a feedback domination design approach which substantially differs from the separation principle, we explicitly construct a Lyapunov–Krasovskill functional to prove the global asymptotic stability with the help of inductive proof method. The control law is discrete-time and linear, hence simulation examples be easily implemented with computers to show the effectiveness of our proposed method. [ABSTRACT FROM AUTHOR]

• UHPC with high elastic modulus was designed via MAA particle packing model. • Workability, microstructure, and mechanical strength of HMUHPC were studied. • Elastic modulus of HMUHPC ranged from 40.5 GPa to 49.3 GPa. • Optimal content of steel chips in HMUHPC was 50 wt%. Elastic modulus is one of the key parameters to weigh the stiffness of concrete members and structural design in civil engineering. Despite its excellent performance in durability and mechanical properties, ultra-high performance concrete (UHPC) is featured with relatively low elastic modulus, which prevents UHPC from being applied in a much larger scope. This study was conducted to explore the feasibility of preparing UHPC with high elastic modulus (HMUHPC) by using steel chips. The modified Andreasen and Andersen (MAA) particle packing model was used to design the initial mixture of HMUHPC. Based on this, some steps were followed to investigate the impacts of varying contents of steel chips on HMUHPC with regard to its mechanical properties, workability, and apparent density. In addition, attention was also paid to how steel chips affected the microstructure of HMUHPC and the ultrasonic pulse velocity (UPV) propagated in HMUHPC. It was found that: 1) Due to the addition of steel chips, there was an increase from 9.65% to 21.73%, 6.38% to 15.85%, 1.28% to 10.49%, and 3.11% to 16.44%, respectively, in the elastic modulus, compressive strength, flexural strength, and apparent density of HMUHPC; 2) The addition of steel chips could reduce the porosity of HMUHPC and optimize its pore size distribution; 3) Considering the effects of steel chips on HMUHPC regarding its microstructure, mechanical properties, and workability, the optimal content of steel chips in HMUHPC was 50 wt%. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of almost disturbance decoupling (ADD) using sampled-data output feedback control for a class of continuous-time nonlinear systems. Under a lower-triangular linear growth condition, a sampled-data output feedback controller is constructed based on the output feedback domination approach, and a Gronwall-Bellman-like inequality is established in the presence of disturbances. Even though a sampled-data controller is employed for easy computer implementation, the proposed controller is still able to achieve ADD under the commonly used continuous-time requirement, that is, the disturbances' effect on the output is attenuated to an arbitrary degree of accuracy in the L2 gain sense. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper considers the problem of global practical tracking via sampled-data control for a class of uncertain nonlinear systems. Under a lower triangular linear growth condition, a sampled-data state feedback controller is first constructed such that the states are globally bounded and the error between the system output and the reference signal will be rendered smaller than a given tolerance. When only the output of the system is measurable, a sampled-data output feedback controller, whose observer and control law are both linear, is constructed to solve the global practical tracking problem. [ABSTRACT FROM PUBLISHER]

• SCM with high elastic modulus was developed by using AMP. • Fluidity, microstructure, mechanical strength, and durability of SCM were studied. • DME of SCM was characterized via ultrasonic testing technology. • DME of SCM was increased by 4.37 ∼ 9.97% due to the addition of AMP. • Durability properties of SCM were markedly improved due to the addition of AMP. Cementitious composites are one of the most widely used building materials in civil engineering. However, their low Young's modulus cannot meet the requirements of long-span structures. This work carried out a feasibility study on producing self-compacting mortar (SCM) with high elastic modulus by using Al 2 O 3 micro powder (AMP). Effects of AMP on the workability, microstructure, mechanical properties, and durability properties of SCM were systematically investigated. The dynamic modulus of elasticity (DME) of SCM was characterized via ultrasonic testing technology. It was found that, 1) due to the addition of AMP, the porosity of SCM was reduced by 2.64 ∼ 13.64%, and the threshold pore diameter of SCM was decreased; 2) the flexural strength and compressive strength of SCM were increased by 4.40 ∼ 15.85% and 2.35 ∼ 14.33%, respectively, because of the incorporation of AMP; 3) the drying shrinkage of SCM was reduced by 6.46 ∼ 11.21%, and the chloride migration coefficient of SCM was decreased by 3.38 ∼ 18.64%, due to the addition of AMP; 4) the optimal content of AMP in SCM was 10%, considering the effects of AMP on the microstructure, mechanical properties, and durability properties of SCM; 5) it was feasible to produce SCM with high elastic modulus by using AMP, and the DME of SCM was increased by 4.37 ∼ 9.97%, because of the incorporation of AMP. [ABSTRACT FROM AUTHOR]

• UHPC with high elastic modulus was design by MAA particle packing model. • Workability, microstructure, and mechanical strength of HEMUHPC were studied. • Elastic modulus of HEMUHPC ranged from 40.50 GPa to 47.13 GPa. • Relationship between elastic modulus and compressive strength was a power function. • Optimal content of alumina micro-powder in HEMUHPC was 10%. 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. [ABSTRACT FROM AUTHOR]

• Producing cement-based sacrificial materials with strontium ferrite is feasible. • Adding strontium ferrite decreases the mechanical properties of cement mortar. • Adding strontium ferrite reduces the drying shrinkage of cement mortar. • Strontium ferrite does not participate in the hydration reaction of cement mortar. • A model between the damage of cement mortar and the temperature is proposed. The safety of nuclear power plant can be improved via core catcher, and cement-based sacrificial materials are widely used in most core catchers because of their simple construction process and the low manufacturing cost. This paper carried out a preliminary investigation to explore the feasibility of using strontium ferrite to prepare cement-based sacrificial materials. The effects of strontium ferrite on the room temperature and high temperature properties of cement mortar were systematically studied in the work. In addition, the damage evolution of cement mortar containing strontium ferrite subjected to elevated temperatures was also identified according to the damage mechanics theory. It was found that, (1) the addition of strontium ferrite led to the deterioration of the mechanical properties, microstructure and pore structure of cement mortar; (2) it was feasible to prepare cement-based sacrificial materials containing strontium ferrite that met the requirements on basic properties like mechanical properties, free water content, volume stability, and the high temperature integrity by controlling the content of strontium ferrite; (3) the correlation between the internal damage of cement mortar and the temperature could be described by Weibull Distribution Model, which provided a basis for the identification and evaluation of serious nuclear power accidents. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a new approach to the problems of analysis and synthesis for nonlinear networked control systems (NNCSs) with limited communication capacity, where a NNCS can be represented by a T–S fuzzy model with two time-varying quantizers. Neither free weighting matrices nor model transformations are employed in the derivation, instead, by constructing an improved Lyapunov function and introducing an extended Jessen''s inequality, an improved stability criteria is obtained. The controller is shown in terms of nonlinear matrix inequalities, which can be computed through solving a convex optimization problem. Numerical examples are exploited to show the usefulness and effectiveness of the results obtained. [Copyright &y& Elsevier]

For complex equipment, it is easy to over-evaluate the impact of failure on production by estimating the reliability level only through failure probability. To remedy this problem, this paper proposes a statistical evaluation method based on fuzzy failure data considering the multi-state characteristics of equipment failures. In this method, the new reliability-evaluation scheme is firstly presented based on the traditional statistical analysis method using the Weibull distribution function. For this scheme, the failure-grade index is defined, and a fuzzy-evaluation method is also proposed by comprehensively considering failure severity, failure maintenance, time, and cost; this is then combined with the time between failures to characterize the failure state. Based on the fuzzy failure data, an improved adaptive-failure small-sample-expansion method is proposed based on the classical bootstrap method and the deviation judgment between distributions of the original and newborn samples. Finally, a novel reliability-evaluation model, related to the failure grade and its membership degree, is established to quantify the reliability level of equipment more realistically. Example cases for three methods of the scheme (the failure-grade fuzzy-evaluation method, the sample-expansion method, and the reliability-evaluation modeling method) are presented, respectively, to validate the effectiveness and significance of the proposed reliability-evaluation technology. [ABSTRACT FROM AUTHOR]

The fabrication of high-performance cement-based materials has benefited greatly from the extensive use of graphene and its derivatives. This paper studies the effects of graphene sulfonate nanosheets (GSNSs) on sacrificial cement paste and mortar (the tested materials) and other siliceous sacrificial materials, especially their ablation behaviors and mechanical properties. Decomposition temperatures and differential scanning calorimetry were used to examine how different contents of GSNSs determines the corresponding decomposition enthalpy of the tested materials and their ablation behaviors. Molecular dynamics was also used to clarify the mechanism how the GSNSs work in the CSH (calcium silicate hydrated)/GSNSs composite to increase the resistance to high temperature. The experimental results show that: (1) the contents of GSNSs at 0.03 wt.%, 0.1 wt.%, and 0.3 wt.% brought an increase of 10.97%, 22.21%, and 17.56%, respectively, in the flexural strength of siliceous sacrificial mortar, and an increase of 1.92%, 9.16%, and 6.70% in its compressive strength; (2) the porosity of siliceous sacrificial mortar was decreased by 5.04%, 9.91%, and 7.13%, respectively, and the threshold pore diameter of siliceous sacrificial mortar was decreased by 13.06%, 35.39%, and 24.02%, when the contents of GSNSs were 0.03 wt.%, 0.1 wt.%, and 0.3 wt.%, respectively; (3) a decline of 11.16%, 28.50%, and 61.01% was found in the ablation velocity of siliceous sacrificial mortar, when the contents of GSNSs were 0.03 wt.%, 0.1 wt.%, and 0.3 wt.%, respectively; (4) when considering the ablation velocities and mechanical properties of siliceous sacrificial materials, 0.1 wt.% GSNSs was considered to be the optimal amount; (5) the GSNSs contribute to the reinforced effect of GSNSs on CSH gel through the grab of dissociated calcium and water molecules, and the chemical reaction with silicate tetrahedron to produce S–O–Si bonds. These results are expected to promoting the development of new kinds of siliceous sacrificial materials that contain GSNSs. [ABSTRACT FROM AUTHOR]

Ultra-high-performance concrete (UHPC) has been used as an advanced construction material in civil engineering because of its excellent mechanical properties and durability. However, with the depletion of the raw material (river sand) used for preparing UHPC, it is imperative to find a replacement material. Recycled sand is an alternative raw material for preparing UHPC, but it degrades the performance. In this study, we investigated the use of graphene oxide (GO) as an additive for enhancing the properties of UHPC prepared from recycled sand. The primary objective was to investigate the effects of GO on the mechanical properties and durability of the UHPC at different concentrations. Additionally, the impact of the GO additive on the microstructure of the UHPC prepared from recycled sand was analysed at different mixing concentrations. The addition of GO resulted in the following: (1) The porosity of the UHPC prepared from recycled sand was reduced by 4.45–11.35%; (2) the compressive strength, flexural strength, splitting tensile strength, and elastic modulus of the UHPC prepared from recycled sand were enhanced by 8.24–16.83%, 11.26–26.62%, 15.63–29.54%, and 5.84–12.25%, respectively; (3) the resistance of the UHPC to penetration of chloride ions increased, and the freeze–thaw resistance improved; (4) the optimum mixing concentration of GO in the UHPC was determined to be 0.05 wt.%, according to a comprehensive analysis of its effects on the microstructure, mechanical properties, and durability of the UHPC. The findings of this study provide important guidance for the utilisation of recycled sand resources. [ABSTRACT FROM AUTHOR]

This study aims to explore the dynamic response of ultra-high performance engineered cementitious composites (UHP-ECC) incorporating waste crumb rubber (CR) at various temperatures, focusing on its potential to enhance the resilience and sustainability of civil infrastructures against low-velocity impacts. To date, the impact behaviour of UHP-ECC under low temperatures has rarely been explored. Firstly, natural river sand and waste tyre CR was utilized to prepare the UHP-ECC. Then, a series of mechanical tests, including compression test, flexural test and uniaxial tensile test were carried out to investigate the static mechanical properties of rubberised UHP-ECCs. In addition, the effects of different waste CR incorporations (0%, 5%, 10%, and 15%) and various temperatures (25 °C, −5 °C, −30 °C, −50 °C, −100 °C and −196 °C) were comprehensively investigated by low-velocity impact tests with constant impact energy. Lastly, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) model was introduced to evaluate the overall performance of UHP-ECC. It was found that the use of river sand and CR significantly enhanced the tensile ductility and impact toughness of UHP-ECC. Impact energy primarily dissipates through damage such as matrix crack initiation, propagation, and fibre pull-out/rupture within the specimen. Adding CR notably decreased stress fluctuations during impact at room temperature, facilitating steady state energy absorption. Moreover, the time to reach peak impact force decreased with decreasing temperature across all UHP-ECC groups. At room temperature during impact process, fibre failure mode is dominated by pull-out failure, while lower temperatures lead to increased fibre rupture at the cracking surface. In low-temperature conditions, the impact response of rubberised UHP-ECC necessitates a comprehensive consideration of the synergistic effects, including material contraction, fibre bridging capacity, rubber phase transition, and water freezing. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract Currently, researchers have been studying ways to reduce the raw materials costs and energy consumption of ultra-high-performance concrete (UHPC) production. Therefore, the feasibility of using aeolian sand to partially or totally replace natural river sand in UHPC is studied. The workability and quasi-static and dynamic mechanical properties were comprehensively studied to investigate the effect of aeolian sand on UHPCs. It was found that: 1) The workability of UHPCs was significantly improved when river sand was partially or totally replaced by aeolian sand; 2) The compressive strength of UHPCs could be enhanced when river sand was partially or totally replaced by aeolian sand, and the differences in flexural strength among all the mixtures were not distinct; 3) Incorporation of aeolian sand as a fine aggregate slightly increased the toughness of UHPCs under uniaxial compression test; 4) The differences in the dynamic impact parameters among UHPCs containing aeolian or river sand, as well as those in the parameter evolution rules regarding impact times, were not obvious. The findings of this research promote the preparation of eco-friendly UHPC and provide a new way to use waste resources. [ABSTRACT FROM AUTHOR]

For enhanced energy utilization with improved flexibility and capability for object manipulation, a focused acoustic vortex (FAV) is devised by installing a spherical acoustic lens on a circular array of planar sector transducers. Based on the acoustic refraction of a concave spherical acoustic lens, numerical simulations show that an FAV with considerable pressure gain and strengthened acoustic gradient force (AGF) can be produced by the effective concentration of acoustic waves. The performance of rotational object trapping is shown by the axial and radial distributions of the AGF for FAVs of different orders. Elastic objects of nanometer, micrometer, millimeter, and even larger-than-wavelength size can be captured with the trapping radius determined by the topological charge. With the established 16-channel experimental system, FAVs of different orders are verified by their clear pressure circles and phase spirals. The trapping radius and rotation speed of object capture are demonstrated using polyethylene particles of various sizes and FAVs of different orders. The favorable results provide an experimentally applicable method of FAV generation using the simplified circular transducer array to accomplish more accurate, stable, and flexible object manipulations with strengthened AGFs. Also, FAVs could offer an efficient means of high-intensity focused ultrasound therapy to improve the therapeutic effect of tumor treatments by accumulating drug particles, thereby enabling more potential applications in clinical practice. [ABSTRACT FROM AUTHOR]

The reliability allocation of machine tools which is a multi-attribute decision-making problem has great significance in designment of machine tools. This paper integrates the intuitionistic trapezoidal fuzzy numbers and performance sorting technique based on similar ideal solutions to achieve the flexible allocation of machine tools reliability. Firstly, intuitionistic trapezoidal fuzzy numbers are employed to integrate decisions made by multiple decision-makers and fuzzy information of their preferences. Then, intuitionistic trapezoid fuzzy numbers' expectations are treated as the weights of criteria. Finally, performance sorting technique based on similar ideal solutions is used to obtain the reliability allocation weight of every subsystem. To investigate the efficacy and simplicity of the provided approach, reliability distribution in a CNC machine tool is introduced as an example to explain its specific contents. It can be concluded that the provided method is more precise and convenient by comparing the results of this approach with those obtained by analytic hierarchy process method. [ABSTRACT FROM AUTHOR]

In actual engineering, material properties, load effects, and other factors of mechanical structures change due to long‐term use. In order to understand the operation of a mechanical structure in real time, it is crucial to obtain the dynamic trajectory of its reliability. Considering the time variability of a mechanical structure over time, uncertain random variables are introduced to express the uncertainty of various parameters of structures, and the Wiener process is used to describe the strength degradation process of structures so as to solve the calculation problem of time‐varying reliability of mechanical structures. Based on the advanced first‐order and second moment method (AFOSM), the proposed linearized Nataf change is used to complete the transformation from related nonnormal variables to independent standard normal variables in order to simplify the calculation process of reliability solution and solve the reliability calculation problem of random parameters subjected to arbitrary distribution. The deduced random variable sensitivity factor indicates the degree of influence of different random variables on the reliability of the mechanical structure, providing a theoretical basis for the optimal design and maintenance of a mechanical structure. The proposed method is analyzed using the cantilever beam and compared with the nonlinear Nataf transform and verified by the Monte Carlo simulation results. The results show that the proposed method can effectively solve the reliability sensitivity problem of structural system strength degradation. [ABSTRACT FROM AUTHOR]

The orbital angular momentum (OAM)-based acoustic vortex (AV) communication has been proven to provide a topological spinning characteristics for data transmission with an improved channel capacity, exhibiting good application prospects in underwater acoustic communications. To improve the accuracy and efficiency of data communication, the spectrum decomposition of OAM modes for OAM-multiplexed AV beams is studied with a simplified structure of single-ring transceiver arrays. The principle of spectrum decomposition for the single-OAM or OAM-multiplexed AV beams is derived based on the phase-coded approach and the orthogonal property of AVs. With the single-ring arrays of 16 transducers and 16 receivers, numerical studies and experimental measurements of eight-OAM-multiplexed AV beams transmitting ASCII codes are conducted. The formation of OAM-multiplexed AV beams is demonstrated by the cross-sectional scanning measurements, and the OAM modes are decoded successfully with a 16-point circular sampling. Compared with the traditional orthogonality-based decoding algorithm, the spectrum decomposition can be realized using a rotational measurement without the multiple premeasurements of single-OAM AV beams. The favorable results demonstrate the feasibility of the spectrum decomposition-based OAM communication for AV beams using a simplified structure of single-ring transceiver arrays, which would facilitate the practical application in underwater communications. [ABSTRACT FROM AUTHOR]

Cytoplasmic stress granules (SGs) are generally triggered by stress-induced translation arrest for storing mRNAs. Recently, it has been shown that SGs exert anti-viral functions due to their involvement in protein synthesis shut off and recruitment of innate immune signaling intermediates. The largest RNA viruses, coronaviruses, impose great threat to public safety and animal health; however, the significance of SGs in coronavirus infection is largely unknown. Infectious Bronchitis Virus (IBV) is the first identified coronavirus in 1930s and has been prevalent in poultry farm for many years. In this study, we provided evidence that IBV overcomes the host antiviral response by inhibiting SGs formation via the virus-encoded endoribonuclease nsp15. By immunofluorescence analysis, we observed that IBV infection not only did not trigger SGs formation in approximately 80% of the infected cells, but also impaired the formation of SGs triggered by heat shock, sodium arsenite, or NaCl stimuli. We further demonstrated that the intrinsic endoribonuclease activity of nsp15 was responsible for the interference of SGs formation. In fact, nsp15-defective recombinant IBV (rIBV-nsp15-H238A) greatly induced the formation of SGs, along with accumulation of dsRNA and activation of PKR, whereas wild type IBV failed to do so. Consequently, infection with rIBV-nsp15-H238A strongly triggered transcription of IFN-β which in turn greatly affected rIBV-nsp15-H238A replication. Further analysis showed that SGs function as antiviral hub, as demonstrated by the attenuated IRF3-IFN response and increased production of IBV in SG-defective cells. Additional evidence includes the aggregation of pattern recognition receptors (PRRs) and signaling intermediates to the IBV-induced SGs. Collectively, our data demonstrate that the endoribonuclease nsp15 of IBV interferes with the formation of antiviral hub SGs by regulating the accumulation of viral dsRNA and by antagonizing the activation of PKR, eventually ensuring productive virus replication. We further demonstrated that nsp15s from PEDV, TGEV, SARS-CoV, SARS-CoV-2 harbor the conserved function to interfere with the formation of chemically-induced SGs. Thus, we speculate that coronaviruses employ similar nsp15-mediated mechanisms to antagonize the host anti-viral SGs formation to ensure efficient virus replication. Author summary: Coronavirus encodes the conserved endoribonuclease nsp15, which has been reported to antagonize IFN responses by mediating evasion of recognition by dsRNA sensors. SGs are part of the host cell anti-viral response; not surprisingly, viruses in turn produce an array of antagonists to counteract such host response. Here, we show that IBV prevents the formation of SGs via nsp15, by reducing the accumulation of viral dsRNA, thereby evading the activation of PKR, phosphorylation of eIF2α, and formation of SGs. Depletion of SG scaffold proteins G3BP1/2 decreases IRF3-IFN response and increases the production of IBV. When overexpressed alone, nsp15s from different coronaviruses (IBV, PEDV, TGEV, SARS-CoV, and SARS-CoV-2) interferes with chemically- and physically-induced SGs, probably by targeting essential SGs assembly factors. In this way, coronaviruses antagonize the formation of SGs by nsp15, via reducing the viral dsRNA accumulation and sequestering/depleting critical component of SGs. To our knowledge, this is the first report describing the role of coronavirus nsp15 in the suppression of integral stress response, in crosstalk with anti-innate immune response. [ABSTRACT FROM AUTHOR]

In the actual production, it is expected to find several sensitivity geometric errors which have great influence on machining accuracy, so as to provide references for the manufacturing, assembly, and other links of the machine tool, and fundamentally improve the working performance. To study this problem, a novel global sensitivity analysis (GSA) method is proposed. Based on the MBS theory, the spatial error model is established to analyze the local influence of geometric error on machining accuracy. An improved second-order partial correlation coefficient based on the Pearson product moment is proposed to analyze the correlation between geometric errors. In addition, the error parameters will change greatly in the stroke of the moving parts. However, the rapid fluctuation of geometric error value will have a dynamic impact on the machining accuracy of machine tools, which is rarely noticed in the previous sensitivity analysis. This change is defined as the fluctuation of error. The high fitting degree function of error-displacement is obtained by using the high order Fourier series and sine series. Then, the fluctuation of the error in the machining stroke is analyzed by using the derivative of the function to the displacement. Through geometric error characteristics (including the local influence, correlation, and fluctuation) are studied comprehensively, the GSA of error is carried out. Finally, taking a machining center as an example and combining the sensitivity analysis results, the improvement measures are proposed to verify the correctness of the method. [ABSTRACT FROM AUTHOR]

To solve the difficulty of generating an ideal Bessel beam, an simplified annular transducer model is proposed to study the axial acoustic radiation force (ARF) and the corresponding negative ARF (pulling force) exerted on centered elastic spheres for acoustic-vortex (AV) beams of arbitrary orders. Based on the theory of acoustic scattering, the axial distributions of the velocity potential and the ARF for AV beams of different orders generated by the annular transducers with different physical sizes are simulated. It is proved that the pulling force can be generated by AV beams of arbitrary orders with multiple axial regions. The pulling force is more likely to exert on the sphere with a smaller k0a (product of the wave number and the radius) for the AV beam with a bigger topological charge due to the strengthened off-axis acoustic scattering. The pulling force decreases with the increase of the axial distance for the sphere with a bigger k0a. More pulling force areas with wider axial regions can be formed by AV beams using a bigger-sized annular transducer. The theoretical results demonstrate the feasibility of generating the pulling force along the axes of AV beams using the experimentally applicable circular array of planar transducers, and suggest application potentials for multi-position stable object manipulations in biomedical engineering. [ABSTRACT FROM AUTHOR]

Background: Genetic variants in the excision repair cross-complimentary group 2 (ERCC2) gene may affect individual susceptibility to cancer by modulating the capability of DNA damage repair. However, the current studies concerning the association of ERCC2 rs13181 polymorphism with ovarian cancer risk provided inconsistent evidence.Methods: This study was to quantitatively summarize the evidence from the individual studies electronically retrieved by a meta-analysis.Results: Totally, nine eligible case-control studies with 1333 cases and 2691 controls were included for the concerned association. Overall, a significant association between ERCC2 gene rs13181 polymorphism and increased risk of ovarian cancer was revealed (CC+AC vs. AA: OR 1.44, 95% CI 1.11-1.86; CC vs. AA: OR 2.12, 95% CI 1.14-3.97). Similarly, in the subgroup analyses, such association was also evident in non-Caucasian population and hospital-based studies. Noteworthily, the recombined analysis with a significant decrease in between-heterogeneity represented a significant association of the variant with increased risk of ovarian cancer after excluding the individual study not in agreement with HWE.Conclusion: The present study suggests that the ERCC2 gene rs13181 polymorphism might be associated with increased risk of ovarian cancer. [ABSTRACT FROM AUTHOR]

In this study, the authors consider the problem of frequency regulation via output feedback for a hydraulic turbine system under unknown load variations. First, to address the difficulties in estimating the unmeasurable states and the unknown load variation, they introduce a universal finite‐time observer (UFTO) which can estimate unmeasurable states, unknown parameters and disturbances under a unified framework. Based on the proposed UFTO, the unmeasurable wicket gate position, the flow rate and the load variation are estimated in a finite time for the hydraulic turbine system. Then by introducing a coordinate transformation, the state‐space model of hydraulic turbine system is converted into a simple form for which a state feedback control law is constructed using the adding a power integrator approach. Combining the UFTO with the finite‐time control law, an output feedback controller is designed to regulate the frequency of the hydraulic turbine system. Computer simulations are also given to validate the proposed finite‐time output feedback controller. [ABSTRACT FROM AUTHOR]

Abstract: A porous spherical aggregation of Li4Mn5O12 nanorods with the particle size of 3μm is prepared by oxidizing LiMn2O4 powder with (NH4)2S2O8 under hydrothermal conditions. The result displays that concentration of (NH4)2S2O8 plays a key role in forming the porous spherical aggregation and the optimal concentration of oxidant is found to be 1.5molL−1. The mechanism for the formation of the porous spherical aggregation is proposed. The electrochemical capacitance performance is tested by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge. The porous spherical aggregation exhibits a good electrochemical performance. It could deliver 375Fg−1 within potential range 0–1.4V at a scan rate of 5mVs−1 in 1molL−1 Li2SO4 and the value is cut down to less than 0.024Fg−1 per cycling period in 1000 cycles. [Copyright &y& Elsevier]

• Based on simulation, a new method for analyzing self-loosening of bolts is proposed. • The simulation with helix angle thread is adopted to improve the analysis accuracy. • The self-loosening behavior of bolt can be caused by elastic slip. • Elastic-plastic deformation is the main factor of bolt self-loosening behavior. • Tightening torque and friction coefficient also affect the self-loosening behavior. The self-loosening of high strength bolt caused by vibration has been widely studied. However, the short-term self-loosening behavior of the high strength bolt when it is not subject to an external load has not received attention. This behavior will also lead the bolt preload to attenuate. Since the theoretical analysis of self-loosening behavior is difficult, this paper uses the finite element method to construct an accurate three-dimensions model with thread lift angle for numerical analysis. A new method is proposed to analyze the self-loosening behavior. The self-loosening behavior caused by the elasticity and plasticity of the bolted joint at different deformation periods is compared and analyzed. Besides, the evolution of the self-loosening behavior under different conditions is explored. The analysis results show that the torsional deformation of the thread leads to the relative slip of the internal and external threads. This results in the self-loosening of the thread in the elastic condition. In the elastic–plastic deformation condition, the self-loosening behavior is caused by the relative slip of the internal and external threads and plastic deformation. The weight of plastic deformation is greater. In addition, this behavior has the characteristics of increasing with increased tightening torque and decreasing with increased friction coefficient. [ABSTRACT FROM AUTHOR]

• Experimental study was carried out to explore performance changes of bolted joints. • Initially, the tangential stiffness is relatively stable, and then drops rapidly. • Under transverse loading, the contact form of fastener body and plate is the same. • The performance of bolted joints can be evaluated with piecewise functions. Threaded fasteners are widely used in a variety of engineering applications. The quality of threaded connections directly affects the service performance. By aiming to acquiring a deeper understanding of the performance characteristics, the mechanical behavior of bolted joint was examined using transverse tensile test. The force–displacement curves of bolted joints exhibit linear characteristics during the first stage, while subsequently the curves exhibit various shapes due to assembly clearance. The tangential stiffness of the bolted joint decreases rapidly when the connected plate slips. And the transverse load threshold between various stages is positively correlated with the clamping force of threaded fastener. The experimental data was fitted to obtain a piecewise function that characterizes the entire slip curve of bolted joints under transverse loading. Main characterization parameters in various stages were analyzed and discussed based on the experimental results, which can aid in the design and using of bolted joints. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]