To investigate the fire resistance of composite beams with restrained superposed slabs, three specimens were tested under uniformly distributed loads in a furnace. The effects of the thickness of the postcast top layer in superposed slabs and the spacing of shear studs on the structural behaviours of composite beams under fire were further examined. During the tests, the temperature distributions of

This paper presents the experimental results of the fineness effect on the pozzolanic activity of Cu-Ni slag in cemented tailing backfill. Cement paste and cemented tailing backfill samples that without or contain Cu-Ni slag with various grinding times were made and cured at 20°C for 7, 28, and 150 days. Mechanical test and microstructural analyses are performed. In general, the pozzolanic activity

Microbeams are key elements in most of the micro-electromechanical systems (MEMS). Electromechanical instability of microbeams in turn plays an important role in their applications. The shape and mechanical properties of microbeams dictate their functional characteristics. Focusing on their instability-based working mechanism, one can appreciate that viscoelasticity of MEMS materials cannot be neglected

The present study is related to the effects of activation energy and thermophoretic diffusion on steady micropolar fluid along with Brownian motion. The activation energy and thermal conductivity of steady micropolar fluid are also discussed. The equation of motion, angular momentum, temperature, concentration, and their boundary conditions are presented for the micropolar fluid. The detail of geometry

The purpose of this paper is to demonstrate a new process technology using the cavitation phenomenon, mainly a water-jet shock microforming, for the fabrication of a metallic foil. 304 stainless steel was exposed to a high-speed submerged water jet with different incident pressures and certain working conditions. In this experiment, a KEYENCE VHX-1000C digital microscope, confocal laser-scanning microscope

Calcium sulfoaluminate cement (CSA) is a low-carbon cementitious material that significantly reduces alkalinity and produces calcium hydroxide-free (CH-free) matrix environment in comparison to ordinary Portland cement (OPC). It might be, however, less efficient towards the passivation of steel in concrete and further investigation before widespread adoption is required. In this project, scanning electron

An adiabatic temperature rise test of cemented sand and gravel (CSG) is conducted, a model for temperature rising of CSG is proposed, and its application to temperature stress prediction of CSG dam is presented. Adiabatic temperature rise tests are first conducted to investigate the temperature rise properties of CSG material with different cementing agent contents. The results demonstrate that the

The types of crude oil for producing asphalt have a decisive influence on various performance measures (including aging resistance and durability) of asphalt. To discriminate and predict the crude oil source of different asphalt samples, a discrimination model was established using 12 greatly different infrared (IR) characteristic absorption peaks (CAPs) as predictive variables. The model was established

The structural behavior of concrete beams containing recycled coarse aggregates (RCAs) was investigated in this study using detailed experimental data. Twelve concrete beams were tested in the experimental program: nine beams with varying RCA contents and three control beams with natural coarse aggregates (NCAs). The parameters for investigating the structural behavior of the RCA concrete beams under

The objective of this research was to understand the dehydration mechanism of technical dihydrate and the variation of the physical properties of β-hemihydrate after the first hydration-dehydration process. In this study, the recycling mechanism of different hemihydrate types as raw material was investigated. The influence of the first hydration-dehydration process on the hydration rate, microstructure

The application of recycled clay brick can not only solve the disposal problem of demolished solid waste but also reduce ecological environment damage caused by the excessive development of resources. Clay brick powder (CBP) exhibits pozzolanic activity and can be used as cement replacement. Recycled clay brick aggregate (RBA) can be used to substitute natural coarse aggregate. Recycled clay brick

The aluminum silent block is the part that connects the front suspension mounting and the road wheels. These products are used in high-speed cars and are subject to high engineering stresses. Over time, fractures occur in the connection part of these products due to insufficient strength. These problems are related to production metallurgy, which led to the concept of this study. During mass production

Conical pick is a rock cutting tool that is commonly used in roadway driving. Pick wear frequently happens in the course of breaking hard rock. The current paper shows a new method to solve the problem of pick wear. The rock is preslit with the saw blade and then broken by the conical pick. In order to study the cutting force and features of rock fragment, the numerical model is built between rock

To establish evaluation criteria for the pavement skid resistance and noise level in tunnels pavements, the zoning and control standards for skid resistance and concrete pavement noise were examined. Transverse friction coefficient (TFC) test equipment and the on-board sound intensity (OBSI) method were used to evaluate the antisliding characteristics and noise levels of several tunnel pavements. The

The investigation of the contact responses is the key for evaluating the local wear of dies in the plastic forming process. This paper investigated the contact load distributions and evolutions of the roller cavities in the compressor blade rolling process by the FEM. It was the first study to quantify the distributions and evolutions of the contact responses for rolling irregular components. The results

Fire extinguishing with the superior performance of fly ash composite colloid material is a cost-effective colloid fire prevention technology. In this paper, a new powder additive (suspending agent (XK-XJ) and gelling agent) was developed for the existing fire extinguishing technology of fly ash compound colloid. Tests show that the best additions to the fly ash slurry were 0.3% and 0.1∼0.3%, respectively

This paper is devoted to the introduction of physicochemical, filler size, and distribution effect in micromechanical predictions of the overall viscoelastic properties of asphalt mastic. In order to account for the three effects, the morphologically representative pattern (MRP) approach was employed. The MRP model was improved due to the arduous practical use of equivalent modulus formula solution

We performed Raman scattering measurements and a comprehensive study of different types of Raman modes associated with phonon vibrations on pure and Ga, Al, Fe, Co, Ni, and Zn doped (110)-oriented PrBa2Cu3O7 (PBCO) thin films to identify the substitution of Cu (1) or Cu (2) ions in PBCO lattice. In Raman spectrum of (110)–oriented PBCO thin film, we observed four prominent Ag type Raman modes at ∼130 cm−1

The relics built with soil are called earthen archaeological sites. Many silt earthen sites exposed to natural environment get seriously damaged and thus require urgent restoration with suitable materials. Previously, lime and glutinous rice slurry were used in the construction of earthen sites. However, lime is usually used in clay, and glutinous rice pulp is difficult to prepare and use on a large

The stability of the two-layer undrained clay slopes should be given considerable attention since they are commonly observed in nature and in manmade structures, and they traditionally have low stability. Therefore, with the elastoplastic finite element method, this paper thoroughly explores the influence of the soil strength parameter cu, slope angle β, and slope depth ratio DH on the slope stability

This work deals with oxygenated apatite synthesis from calcium chloride and phosphoric acid using a wet precipitation method. An experimental design is applied to precise the influence of the synthesis parameters (pH of the reaction medium, atomic ratio Ca/P of the reagents, concentration of the calcium solution (Ca2+), temperature of the reaction medium (T), and duration of the reaction (D)) on the

This work is aimed at studying asymmetric ((BT) /(BZ)) superlattices, grown by pulsed laser deposition onto (001) MgO substrates. The thicknesses of BT (ferroelectric) and BZ (paraelectric) layers were varied so that х ranged from 0 to 1 at a modulation period of about 80 Å. The films were 400 nm thick. The out-of-plane lattice parameters of constituents were assessed using X-ray diffraction. The lattice

The accurate measurement of effective absorption capacity is crucial for highly absorptive materials when they are used within cement-based materials. In this study, a method for examining effective absorption capacity using isothermal calorimetry is reviewed and investigated in detail to accommodate different circumstances. Specifically, the effect of different pore structures and water-to-cement

Most previous studies on the strength properties of coal bottom ash (CBA) concrete have focused on concrete with a normal compressive strength, and thus, studies on the strength properties of high-strength concrete (HSC) containing CBA are limited. Therefore, the effects of replacing fine aggregates with CBA and variations in the curing age on the strength properties of HSC with a compressive strength

In the upper soft and lower hard composite strata, it is very difficult to sample the rock and test the mechanical properties of the samples. The study of the mechanical properties of similar material samples by artificial manufacture may enable an alternative method to solve this problem. Therefore, the feasibility of artificial sample preparation and the test of mechanical properties of rock samples

Aiming at the problem of large deformation and instability failure and its control of soft coal and soft roof roadway under intense mining, laboratory experiments, theoretical calculations, Flac3D numerical simulation, borehole peeping, and pressure observation were used to study the deflection characteristics of the deviatoric stress of the gas tailgate and the distribution and failure characteristics

To rapidly restore the seismic behaviour of a portal steel bridge column after an earthquake, the installation of replaceable tubular steel piers at the root of a portal steel bridge column is proposed herein. In this study, various tubular steel piers with different structural measures were designed; an axial compression test and a numerical simulation of the newly designed tubular steel piers were

The fracture energy of the high-performance fiber-reinforced cement-based composite (HPFRCC) can be modified within wide limits by the variation of the amount of steel fibers added to the fresh mix. First of all, considering the actual engineering conditions in Qingdao, the materials commonly used in Qingdao were selected. The optimal reference mix proportion of the HPFRCC cementing material was proposed

The synergistic effects of transition metal based nanocomposites are known to possess enhanced antibacterial activities. However, in-depth analysis of the relative antibacterial performance of some of the prominent nanocomposites remains unavailable. This study compares the antibacterial activity of two separate nanocomposites, which are copper oxide with silver (CuO/Ag) and zinc oxide with silver

Ageing treatments were performed on Ti-50.53 at.% Ni shape memory alloy corrugated gasket (SMA-CG) units. The results of phase transition temperature, shape-setting, compression-resilience performance, and the shape memory effect (SME) of NiTi corrugated units were investigated. The experimental results show that high austenite finish temperatures could be achieved at 500°C and at 400°C aged for a

Friction stir welding (FSW) is the most popular and efficient method for solid-state joining of similar or dissimilar metals and alloys. This technology is mostly applied in aerospace, rail, automotive, and marine industries. In order to reduce the weight of special auto parts, friction stir spot welding (FSSW) was proposed by some researchers for the connection of steel-aluminium dissimilar metals

In the present work, the hot deformation behavior of TB18 titanium alloy was investigated by isothermal hot compression tests with temperatures from 650 to 880°C and strain rates from 0.001 to 10 s−1. The flow curves after friction and temperature correction show that the peak stress decreased with the temperature increase and the strain rate decrease. Three typical characteristics of flow behavior

Soft and hard composite rock strata are frequently encountered in transportation, geotechnical, and underground engineering. However, most of the current support is designed for homogeneous rock masses, which ignores the different anchoring effect in soft and hard composite rock strata. A numerical study is presented in this paper on the pull-out behavior of fully grouted rock bolts in soft and hard

Rubber spring plays an important role in improving train performance, so the study of rubber spring is one of the focuses of train dynamics. The vertical characteristic parameters of rubber spring are affected by prepressure significantly, as a result of varying parameters of static stiffness, dynamic stiffness, periodic energy consumption, damping coefficient, and so on. In order to use the theoretical

This paper selects polyvinyl chloride- (PVC-) coated fabrics to study its off-axial tensile behaviors under different off-axis angles including 0°, 15°, 30°, 45°, 60°, 75°, and 90°. In the experiment, dumbbell-shaped and strip-shaped specimens are analyzed for shape effect. The variations in the strain distribution are studied by using digital image correlation (DIC) noncontact full-field measurement

Improving roadway stability in deep underground mines is quite challenging, as the conventional support structures easily fail. Roadway collapse and large deformation occur just several months after tunnel excavation. In this study, a relatively new prereinforcement technique, the jet grouting (JG), is introduced to improve roadway stability. A field test was performed for evaluating the practicability

The mechanical analysis of interlayer bonding problem of asphalt pavement is performed by the elastic layered system theory or finite element method (FEM); then, a lot of specialized programs based on the above theories emerged successively, of which BISAR3.0 and EverStressFE are quite representative. In order to further clarify the characteristics of BISAR3.0 and EverStressFE for investigating interlayer

In order to adapt to dry and wet environment in mine roadways and improve the performance of sealing materials under different environmental conditions, this study selected the materials based on their ability to spray and found that the materials with a viscosity of 1500–6000 MPa·s can achieve a balance between performance of spray and wall-hanging performance. Next, by selecting high-elastic polyacrylate

The twin-roller casting process is a novel technology used to produce aluminium and other alloys. In this study, the Al-Fe-Si alloy was twin-roller cast into a billet with a thickness of 7.0 mm. This was followed by an annealing process at 480°C for 16 hours. Abnormal grains of more than 15 mm in the nominal diameter were found to have formed on the surface of the billet. Scanning electronic microscopy

The shallow unconsolidated stratum in the offshore oilfield is characterized by large porosity, low temperature, and weak formation and often faces problems such as low density and poor compressive strength of a cement slurry, among others, which pose serious challenges to construction. A high-performance low-density cement slurry system must be used for cementing to ensure the safety of subsequent

The combined surface and underground mining method is typically used in an open-pit mine for better production and profits. However, the improved scale of mining operations at the combined mining conditions results in even more intensive strata movement and massive ground damages. This paper assesses the progressive development of the characteristics of roof movement with the longwall face advance

Following foreign object damage (FOD), a decision to repair components using novel additive manufacturing (AM) technologies has good potential to enable cost-effective and efficient solutions for aircraft gas turbine engine maintenance. To implement any new technology in the gas turbine remanufacturing world, the performance of the repair must be developed and understood through careful consideration

Cemented paste backfill (CPB) allows environmental friendly management of potentially hazardous tailings generated from milling of nonferrous metal sulphide ores by placing such tailings into the underground mined-out openings. The components of CPB are tailings, water, and binders. These components significantly affect the physicomechanical, workability, and geotechnical properties of CPB. Ordinary

The fitting analysis of soil-water characteristic curve (SWCC) is the foundation of engineering properties of unsaturated soils. The purpose of this paper is to explore the differences of fitting effects between different fractal and empirical models as well as the effect of residual water content θr on the model fitting. The experimental SWCCs of Hunan clay at different initial dry densities are measured

To solve the problem of unstable sealing in the sealing section of a gassy, soft coal seam, a seal reinforcement material for gas extraction boreholes was developed, which was mainly made of ordinary Portland cement and blended with additives such as aluminium powder, quicklime, and gypsum. Firstly, in order to obtain the necessary expansion and compressive strength of reinforcement material, key factors

In this paper, an experimental study of the variation of resistivity of coal samples in different bedding directions at 1 MHz frequency was performed by establishing an experimental system for resistivity testing of coal under triaxial stress. The low-pressure nitrogen gas adsorption (LP-N2GA) experiment and scanning electron microscopy (SEM) were obtained to analyze the pore-fracture structural characteristics

Chloride diffusion is the major factor that affects the life of concrete structures. The time-fractional order equation can be used to describe anomalous diffusion in reinforced concrete. In this work, a time-fractional model of chloride diffusion is solved via the meshless method. The Element-Free Galerkin (EFG) meshless method does not require meshing. One-dimensional and two-dimensional numerical

The objective of this work was to examine the compressive strength behavior of ground bottom ash (GBA) concrete by using an artificial neural network. Four input parameters, specifically, the water-to-binder ratio (WB), percentage replacement of GBA (PR), median particle size of GBA (PS), and age of concrete (AC), were considered for this prediction. The results indicated that all four considered parameters

The absorbent resin for Cu2+ removal was prepared under microwave irradiation through grafting acrylamide (AM) and acrylic acid (AA) to cellulose. The initiator is a kind of redox system composed of potassium persulfate/sodium thiosulfate. The crosslinking agent is N,N′-methylene bisacrylamide. The optimal reaction conditions are as follows: the ratio of AA to cellulose is 10 : 1, initiator to AA is

Due to the heterogeneity of the internal structure and the different external loading conditions, the mechanical and acoustic emission (AE) characteristic parameters of coal and rock are discrete in the process of loading until failure, and many repeated and destructive tests need to be completed to obtain the performance parameters. It is of theoretical significance to explore the correlation of various

In order to optimize the wall thickness distribution of medical balloon, kyphoplasty balloon was chosen as the research object, the uniformity of wall thickness distribution was taken as the evaluation index, and the influence of stretch blow molding process on the uniformity of kyphoplasty balloon was investigated. In this paper, 16 sets of orthogonal test schemes were studied by selecting four main

This study aims to evaluate the effect of different rejuvenators and antistripping agents on the healing performance of hot mix asphalt (HMA). Two damage HMA series (e.g., moisture damage and aged damage) were subjected to either induction or microwave heating. A PG64-22 virgin and aged binder were used and modified with several additives. Three long-term aged binders (e.g., PAV5, PAV15, and PAV20)

The dielectric permittivity of synthetic rubber polymers, nitrile butadiene rubber (NBR) and ethylene propylene diene monomer (EPDM), with both frequency and temperature variations, was thoroughly investigated by dielectric relaxation spectroscopy (DRS). The spectrum versus frequency of DRS was analyzed with the semiempirical Havriliak–Negami formula and conductivity contribution by employing the newly

H13 steel surfaces are covered by coatings of Co-based alloy with 0, 10, 20, and 30 wt. % TiC using the laser cladding (LC) method. The morphological characteristics, growth mechanism, and the mechanical properties of TiC on the microstructure of the coatings were studied. The results show that TiC in the TiC/Co50 composite coating is composed of two parts: incompletely melted TiC and in situ TiC.

A novel stick-slip rotary piezoelectric actuator is designed for optical use. The actuator is proposed, fabricated, and tested with the aim of realizing both fine resolution and a long stroke. The dynamic model of the actuator is established, and simulations are performed to discover how the input driving voltage affects the stick-slip motion of the actuator. An experimental system is built to evaluate

With the development of electronical technology and the construction of the fifth-generation cellular networks, electronic devices with higher integrated level and power are widely applied. Hence, greater demands are being placed on electronic packaging materials. High-Pb solder alloys were widely used for low- and medium-temperature soldering for the past decades but have been prohibited due to toxicity

In this paper, four antiskidding surface test sections were paved to investigate the long-term skid resistance of the improved dense-graded asphalt concrete in Guangdong Province (GAC) using diabase fine aggregate instead of limestone. Four test sections were tested by the accelerated loading equipment (MLS11, mobile load simulator). The reduction law of the long-term skid resistance of GAC-16 was

The necessity of the use of several mobile services increases every day. This requires the consumption of energy rates. Hence, minimizing the energy and interferences of mobile users are major concerns of Heterogeneous Networks (HetNet). This paper aims to improve the energy of mobile users by minimizing a weighted function. To consider significant weights values, we have exploited the multicriteria

A comparison was made between Mg alloy and A3 steel on weight, bending, sound absorption, and vibration conditions. In this study, a swivel plate, which is used in rotating car seats, is to be taken into consideration for finding bending, natural frequency, and frequency under static loading conditions. The swivel plate is generally made up of A3 steel plate; instead, we have replaced that with Mg

In order to prevent smoke from flowing backward and penetrating into adjacent tunnel through cross channels during evacuation in case of fire accidents in highway tunnels, it is extremely necessary to implement the linkage control scheme for double-hole tunnel ventilation system. Therefore, six linkage control schemes for ventilation system are proposed in this article. Firstly, these six schemes were