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This study aimed to evaluate the potential of utilizing aerated concrete (AC) and clay bricks (CB) sourced from construction and demotion waste (CDW) as low-cost adsorbents for the removal of Pb2+ from aqueous solutions. The effects of various parameters, including particle size, solution pH, contact time, adsorbent dosage, and initial Pb2+ concentration, were analyzed through batch experiments. The results indicated that AC performed more efficiently in removing lead ions than CB under all the tested conditions. The highest removal efficiency of Pb2+ with AC was 99.0%, which was achieved at a pH of 5.0, contact time of 1 h, an adsorbent dosage of 5 g/L, and an initial Pb2+ concentration of 100 mg/L. The maximum adsorption capacities of AC and CB were 201.6 mg/g and 56.3 mg/g, respectively. The adsorption isotherm data of the adsorbents were successfully modeled using both the Langmuir and Freundlich models. The removal of lead ions from aqueous solutions by both adsorbents is primarily achieved through adsorption and microprecipitation. Compared to CB, AC exhibited superior performance, attributed to its larger specific surface area, pore volume, and alkalinity. The cost-effectiveness and availability of AC make it a promising candidate for treating of Pb-contaminated wastewater, providing a new way for resource utilization of CDW.

The durability of ultra-high-performance concrete (UHPC) exposed to freezing–thawing (F–T) is closely associated with its micromechanical properties. In this study, the nanoindentation technique is employed to characterise the micromechanical properties of UHPC at different F–T cycles. It is observed that the indentation moduli of low-density calcium silicate hydrate, high-density calcium silicate hydrate, and calcium hydroxide in the studied UHPC decrease moderately with the decreasing ranges of 11.58, 14.56 and 3.3%, respectively, after undergoing 1500 F–T cycles. More micropores gradually form, converge and connect, and the volume fraction of micropores increases up to about 120%. The interfacial transition zone (ITZ) between steel fibre and cement paste is more prone to act as the weakest zone than that between fine sand and cement paste. The thickness of ITZ enlarges from 22 μm of the unconditioned stage to 60 μm at 1500 F–T cycles. Based on the micromechanical properties obtained from the nanoindentation test, the modulus of elasticity values of UHPC under different F–T cycles are predicted using the multiscale homogenisation model. It is proved that the combined micromechanical characterisation and multiscale homogenisation technique is capable of predicting the macromechanical properties of UHPC and their changes under F–T action.

A surface plasmon resonance imaging (SPRi) platform integrated with a smartphone was constructed for the simultaneous and sensitive detection of acute kidney injury (AKI) biomarkers. The smartphone SPRi platform was developed without the requirement of additional light and power sources. The LED flash of the smartphone was used as the light source for the excitation of surface plasmon resonance of a gold sensor chip based on the Kretschmann configuration, while the reflected light was collected by the camera of the smartphone. This smartphone SPRi system was conveniently fabricated by 3D printing and showed a sensitivity of 1.78 × 10

Here a scheme for solving the nonlinear integral equation of Volterra-Hammerstein type is given. We combine the related theories of homotopy perturbation method (HPM) with the simplified reproducing kernel method (SRKM). The nonlinear system can be transformed into linear equations by utilizing HPM. Based on the SRKM, we can solve these linear equations. Furthermore, we discuss convergence and error analysis of the HPM-SRKM. Finally, the feasibility of this method is verified by numerical examples.

While the application of nanoindentation technology has made great progress in cemented materials, the nanoindentation data show great discreteness. This study proposes an efficient procedure for c...

Bimetallic CuAg nanoparticles were synthesized using uric acid as a stabilizer, Fe3O4 loaded CuAg nanoparticles (Fe3O4–CuAg NPs) were also fabricated, and the morphology and content of both CuAg NPs and Fe3O4–CuAg NPs were investigated. The bimetallic CuAg NPs can be used as a catalyst and exhibited superior catalytic performance in the hydrogenation of nitrophenols and potassium ferricyanide(III). Notably, the bimetallic CuAg NPs and Fe3O4–CuAg NPs showed better catalytic activity compared with the same amount of Ag NPs in the hydrogenation of 4-nitrophenol, with rate constants k of 20.02 × 10−3 s−1 and 20.19 × 10−3 s−1, respectively. The magnetic Fe3O4–CuAg NPs can be re-used as a catalyst at least five times, promoting the concept of recycling by improving the deficiency in the disposable use of colloidal nanoparticles.

As advanced scenarios are developed for tokamak operations, the demand for flexibility of the electron cyclotron emission (ECE) channels’ locations has increased. The tunable feature of yttrium iron garnet (YIG) filters provides this spatial flexibility. Here, we present a method of performing ECE measurements on fixed flux surfaces instead of fixed frequencies. This is achieved by adjusting YIG filters utilized in the intermediate frequency section to frequencies associated with flux surfaces in regions of interest during the discharge. The key components are the application of tunable YIG filters and a control program that calculates the filter settings using flux information from real-time reconstruction equilibria (EFIT). This fast procedure facilitates Te measurements in regions of interest to investigate plasma dynamic behaviors.

Evidence from terrestrial sedimentary heavy metals record is a robust indicator of anthropogenic activity changes. Heavy metals and particle sizes in 210Pb-dated sediment cores extracted from Hulun and Chagan lakes were measured to reconstruct the sediment record and evaluated health risk of heavy metals in the last 150 years in Northeast China. In general, the particle size of Hulun Lake was finer with more contents of clay than Chagan Lake, while the concentrations of most heavy metals in Hulun Lake was lower. Prior to the 1970s, significant positive correlations between most heavy metals and clay, indicating that that they were likely co-transported and both lakes were dominated by natural inputs. The two records showed significant increases in concentrations of heavy metals between 1970s and 1990s, which were associated with recent anthropogenic activities derived from principal component analysis of clay and heavy metals. Specifically, the exploitation of mineral resources and traffic source in the Hulun Lake, and the emissions of pesticides and fertilizers from agricultural activity, and the combustions of coal and fossil fuels from industrial activity in the Chagan Lake. Since 1990s, natural processes was the main source of heavy metals in Hulun Lake due to the environmental protection policy, while emissions of industrial, agricultural and domestic sewage were still the main source in Chagan Lake. Overall carcinogenic risks caused by single heavy metal elements determined for the two lakes were considered to be acceptable. However, Cr was associated with a risk for children across since 1970s which should be paid more attention.

In order to explore frost resistance mechanism of ultra-high performance concrete (UHPC) under freeze-thaw (F-T) action, the microstructures and micromechanical properties of two interfacial transition zones (ITZ) of steel fiber-paste and fine sand-paste are investigated using nanoindentation technology. The experimental results demonstrates that there exits an obvious weak zone in the ITZ of fiber-paste, of which the microstructure is largely affected by F-T action. The relative variation of the amplitude of modulus and hardness of calcium silicate and calcium hydroxide is less than 0.2 under F-T action. The volume fraction of micropores increases exponentially as the increase of F-T cycles, and the pore size gradually extends to tens of microns. The thickness of ITZ between steel fibers and paste gradually increased from 20 to 65 μm after 0–1500 F-T cycles. Thus, the volume fraction of micropores and the thickness of ITZ in steel fibers can be used to effectively characterize the degradation of micromechanical properties of UHPC under cold climates.

Utilizing variable-frequency channels, e.g., yttrium iron garnet (YIG) bandpass filters, in the intermediate frequency (IF) section of an electron cyclotron emission (ECE) radiometer facilitates flexibility in the volume viewed by the ECE channels as well as high resolution electron temperature and temperature fluctuation measurements in tokamaks. Fast modulating electron cyclotron emission (FMECE), a stand-alone IF section with eight channels, is a novel application of YIG filters for real-time electron temperature gradient and gradient scale length measurements. Key to FMECE is a simultaneous input/output data acquisition unit, as well as a modified type of YIG filters, which is capable of fast switching of their center (set) frequencies with a frequency slew rate of 600 µs/GHz. A new FMECE has been implemented and tested on the DIII-D tokamak, demonstrating its capability in real-time gradient measurements. The data presented here shows that FMECE can identify flattening in the electron temperature profile; the latter can be used as a sensor for real time monitoring and control of plasma instabilities. Implementation and application are planned for the EAST tokamak.

Municipal solid waste incineration bottom ash is atypical of granular material and it is significantly important to investigate the engineering properties of bottom ash used as aggregate of embankments and road base, especially the shear strength and deformation characteristics. The laboratory tests were performed on engineering properties of bottom ash from an incineration plant in China. The results show that the grain sizes of bottom ash focus on the range of 2–50 mm and is well-graded. Bottom ash can be reused as a non-hazardous material. Both unsaturated and saturated bottom ash appear to be plastic failure, and have friction angle and cohesion. The maximum friction angle and cohesion of unsaturated bottom ash are 47.8° and 56 kPa, respectively, which has higher shear strength and better stability than coarse sand and gravel. The elastic modulus of bottom ash increases with maximum deviator stress and bottom ash has better resistance capacity to deformation.

An analytical model is proposed to predict the tensile behavior of Ultra-High Performance fiber-reinforced Concrete (UHPC) with extended cyclic freezing-thawing (F-T) actions. Based on the work mechanisms of stress transfer at the matrix-fiber interface, the fiber pullout behavior is modeled, from which the combined effects of fiber orientation, fiber snubbing and matrix spalling on the tensile responses of UHPC are characterized with a fiber reinforcement efficiency function. The nanoindentation test results show that the interfacial transition zone (ITZ) between steel fiber and cementitious matrix deteriorates over the F-T period, and the thickness of this ITZ weak band gradually increases from 22 μm at 0 cycle to 60 μm at 1500 F-T cycles. A good agreement is achieved between the analytical and experimental tensile responses of UHPC at various F-T cycles, and the predictability of the model is improved by adjusting the coefficients that govern the softening branch of tensile stress-crack width curves. The proposed analytical model can be used to effectively predict the tensile behavior of UHPC and its degradation effect due to F-T actions.

The presence of a natural boundary in the angle complex plane of the function conjugating an area preserving map with a rotation is a signature of nonintegrability. Numerical results suggest that the boundary arises from the condensation of singularities when a real nonresonant frequency is approaohed by a sequence of complex resonant frequencies. For the quadratic map of the complex plane F:z'=λz+z 2 the function conjugating the linear part of F with F has q cuts with end points on a spiral if λ=e 2πip/q-a with a a>0. When p/q tends to a (quadratic) irrational number and a→0 the points coalesce on the boundary of a circle, whose image is the Siegel disk

The color histogram of an image has been widely used as a feature descriptor for the image in content-based retrieval applications. In this paper, we report some results from our investigation efforts into its usage. We outline three typical color space quantization schemes used in our experiments, and introduce the soft-decision histogramming method to eliminate the discontinuity problem in traditional color histogram population process. Then, to improve the effectiveness of color histogram-based retrieval algorithms, several similarity metrics are proposed for comparing color histograms, including three special forms of the Kantorovich metric.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

High quality video compression is necessary for reduction of transmission bandwidth and in archiving applications. We propose a compression scheme which, depending on the available bandwidth, can vary from lossless compression to lossy compression, but always with guaranteed quality. In the case of lossless compression, the customer receives the original content without any loss. Even the lower compression ratios obtained with lossless compression can represent significant savings in the communication bandwidth. In the case of lossy compression, the maximum error between recovered and the original video is mathematically bounded. The amount of compression achieved is a function of the error bounds. Furthermore, errors are statistically independent from the video content, and thus guaranteed not to create any type of artifacts. So the recovered video has the same quality, visually indistinguishable from the original, at all times and all motion conditions.