This paper studies the validity of impact-echo method for determining dynamic modulus elasticity concrete. It is found that P-wave speed obtained using on standard specimens corresponds well with theoretical one-dimensional speed. Also, moduli from are essentially same those conventional transverse resonant frequency method. recommended estimates should not be based static alone.

This study presents part of a pilot work for the structural health monitoring large tied-arch reinforced concrete aqueduct in eastern China. Based on field-monitored data over year, it mainly focuses effect air temperature and water load variations static behavior typical span through field 3D FE model analysis. It is found that longitudinal deformation composite shows good linear relationship with during non-operation period also has bilinear correlation level operation. However, isolation...

Under the background of ecological civilization construction in new era “carbon neutrality and carbon peaking,” there is an urgent need to develop more efficient environmentally friendly methods address challenges posed by traditional enhanced crude oil recovery (EOR) technologies. Scenedesmus was cultured laboratory, with its main components—pigments, proteins, lipids—utilized as modifiers dispersants for quantum dots (C-Dots). The resulting bio-nanofluid exhibits excellent water solubility...

Three types of stress-strain relations high-strength concrete under triaxial compression, axial stress–axial and lateral strain, octahedral normal stress–volume change, shear curves, are studied in this paper. The influence different load paths is also addressed. Saenz equation found to be appropriate represent the relation low confining pressures. A between peak stress strain developed, which can used define point on curve from stresses obtained failure surface. experience degradation...

Abstract The prediction of river runoff is crucial for flood forecasting, agricultural irrigation and hydroelectric power generation. A coupled model based on the Gravitational Search Algorithm (GSA) Seasonal Autoregressive Integrated Moving Average (SARIMA) proposed to address non-linear seasonal features data. GSA has a significant local optimisation capability, while SARIMA allows real-time adjustment using historical data suitable analysing time series with variations. Consequently,...

Graphene/Fe₃O₄ hybrid particles synthesized by co-precipitation can be finely dispersed in NBR as fewer-layered sheets, resulting great improvement on mechanical property of composite even at very low filler content.

With the aim of improving anti-aging properties nitrile-butadiene rubber (NBR), a functional organic filler, namely LDH–SAS, prepared by intercalating 4-amino-benzenesulfonic acid monosodium salt (SAS) into layered double hydroxides (LDHs) through anion exchange, was added to giving NBR/LDH–SAS composites. Successful preparation LDH–SAS confirmed XRD, TGA and FTIR. well dispersed in NBR matrix, owing its strong interaction with nitrile group NBR. The obtained composites exhibited excellent...

The current methods for evaluating the contact condition between concrete and lining were ground penetrating radar (GPR) coring method. penetration of electromagnetic waves was greatly affected by steel reinforcement water, which often made detection results GPR unsatisfactory. A spectral analysis surface wave (SASW) method used to evaluate concrete-bedrock interface hydraulic tunnel linings in this paper, since impact elastic is less bars water content. An SASW implementation program based...

This paper presents the results of an analytical and experimental programme to study validity measuring P-wave speed reduction by impact-echo method as alternative conventional resonance for evaluating frost resistance concrete. It was found that, when subjected freeze–thaw cycles, relative dynamic moduli elasticity (E d ) concrete obtained from two methods are in good agreement E is above 60%. The also show that decrease correlates well with degradation increasing implying frequent...

ABSTRACT Different surface functionalized Fe 3 O 4 were added to ethylene vinyl‐acetate copolymers (EVA) composite hot melt adhesives (HMAs) study their influence on the properties of HMAs. The adhesion and viscoelastic for HMAs studied using an electromechanical universal testing machine, dynamic mechanical analyzer (DMA) parallel‐plate rheometer, respectively. Orientation structure was by Infrared dichroism. results showed that tetraethoxysilane (TEOS) treated better compatibility with EVA...

Fe₃O₄ particles were surface coated with a layer of polyvinyl acetate (PVAc), which could improve their compatibility EVA composite hot melt adhesives and then further induce segments to orientate.

Graphene oxide (GO) was modified by p-phenylenediamine (PPD), aiming at improving the wet-skid resistance and reduce rolling loss of solution polymerized styrene-butadiene rubber (SSBR). PPD with amino groups enabled GO to obtain anti-aging function. The structure (PPD-GO) characterized Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) Raman spectroscopy. Mechanical tests showed that mechanical properties SSBR before after aging were improved adding PPD-GO. results...

Abstract The shape of bridge piers across rivers is one the significant factors that affect backwater in river. study on influence pier shapes flow patterns river valuable to design and flooding. Based MIKE21 Flow Model hydrodynamic model, dynamic numerical simulations were conducted investigate effect different water flow. result shows rectangular, circular elliptical have a blocking changed local areas near piers. Under same rate, rectangular was largest, followed by piers, smallest. value...

Abstract Block copolymer nanolithography has attracted enormous interest in chip technologies, such as integrated silicon chips and biochips, due to its large-scale mass production of uniform patterns. We further modified this technology grow embossed nanodots, nanorods nanofingerprints polymer brushes on from their corresponding wet-etched nanostructures covered with pendent SiH x ( X = 1–3) species. Atomic force microscopy (AFM) was used image the topomorphologies multiple...

ABSTRACT There were many phosphorus chemical enterprises and phosphogypsum slag fields in the Fuquan section of Chong-an River Guizhou Province China; therefore, dissolved Fengshanqiaobian water quality monitoring area has exceeded 0.2 mg/L for a long time. This study analyzed data phosphorus, fluoride, nitrate–nitrogen, oxygen demand main stream key tributaries from 2015 to 2021, which exceeding factor was more than mg/L; determined variation law pollution body River, exceedance mainly...

The carbon nanotubes (CNTs) reinforced 2A70 alloy by the coating of ZrO 2 (ZrO @CNTs/2A70) are processed a hot extrusion process. microstructure and mechanical properties @CNTs/2A70 composites were investigated in this study. results show that second phase is broken uniformly dispersed under action shear force as well @CNTs reinforcement distributed along direction. process eliminates cast defects improves reinforcing phase's dispersion material's significantly improved. At ratio 25,...

ABSTRACT Wastewater generated in the production of phosphorus flame retardants contains benzene, xylene, acetophenone, and 9, 10-dihydro-9-oxa-10-phosphoxanthine-10-oxide (DOPO) with larger benzene rings, which are more difficult to biodegrade directly. In this study, wastewater applied for high-temperature nylon reactive retardant was first treated by combined process lime emulsion–flocculation reaction precipitation–ozone oxidation degradation DOPO, then processed secondary upflow...

Monitoring the degradation of dynamic elastic modulus (Ed) concrete is great importance to track durability deterioration for hydraulic structures. For aqueduct under investigation in this study, bent frames and moment frame supports (Ed-frame), arch trusses (Ed-arch) shear stiffnesses asphaltic bearings U-shaped flumes (Kflume) are main parameters define behavior structure, which have direct correlation with its vibrational characteristics thus practicably can be estimated by a BP...

Abstract The content of trace impurities, such as interstitial oxygen and substitutional carbon, in silicon is crucial determining the mechanical physical characteristics wafers. traditional infrared (IR) method adopted a normal means to analyse their concentration at home abroad, but there are two problems. first problem poor representativeness single local sampling point because impurity distribution solid sample not uniform that liquid sample. second interference fringes appear spectra...