Towards green asphalt materials with lower emission of volatile organic compounds: A review on the release characteristics and its emission reduction additives

Recently, researchers in the road field are focusing on the development of green asphalt materials with loweremission of volatile organic compounds (VOCs). The characterization methodology of asphalt VOCs and theinfluencing factors on VOCs release have always been the basic issue of asphalt VOCs emission reduction research.Researchers have proposed a variety of asphalt VOCs characterization methodologies, which also have mutuallyirreplaceable characteristics. Asphalt VOCs volatilization is affected by many factors. In this study, asphalt VOCscharacterization methodologies were summarized, including their advantages, disadvantages, characteristics andapplicable requirements. Subsequently, the influencing factors of VOCs release, such as asphalt types and environment conditions, are summarized to provide theoretical support for the emission reduction research. Theclassification and mechanism of newly-development asphalt VOCs emission reduction materials are reviewed. Thereduction efficiencies are also compared to select better materials and put forward the improvement objective ofnew materials and new processes. In addition, the prospects about development of VOCs release mechanism ofasphalt materials during the full life cycle and feasibility research of high-efficiency composite emission reductionmaterials in the future were put forward.

Influence of Silica Fume on the Reflectivity and Transmission Efficiency of Cement-Based Materials

As a kind of mineral admixture, silica fume has low permittivity, which will affect the electromagnetic properties of cement-based materials. To study the effect of silica fume on the properties of cement-based materials, the reflectivity, transmission efficiency and pore structure were analyzed by using the vector network analyzer and mercury injection apparatus. Results show that silica fume can make the mortar more compact and the porosity of sample with 9% silica fume is only 17.8%, which is far lower than the control sample;With the increase of the silica fume content, the peak of reflectivity curve increases from -23.2 dB to -16.0 dB, and then decreases from -16.04 dB to -28.7 dB in the frequency range of 6 – 18 GHz. Reflectivity of sample with 3% content of silica fume is lower than other samples within 26.5 - 40 GHz;Transmission efficiency of samples shows the trend of increase with silica fume content increases from 0% to 6% within 8.2 - 12.4 GHz, 12 - 18 GHz and 26.5 - 40 GHz, but when the content increases from 6% to 9%, the transmission efficiency of samples reduces.

Enhanced properties of stone coal-based composite phase change materials for thermal energy storage

Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite preparation.We prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an additive.The combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading capacity.Results showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface area.The loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% EG.These data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed composite.The obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical compatibility.The SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.

Progress in Resource Utilization of River Sediment in the Field of Building Materials

At present,there is a great demand for building materials in the market,and the market prospect of building materials is relatively considerable.Through studying the composition of river sediment and its resource utilization in the field of building materials,this paper expounds the current domestic scholars research on river sediment in building materials,and summarizes the current problems and challenges,so as to provide a reference for the sustainable development of river sediment in the field of building materials.

Review of the fabrication and application of porous materials from silicon-rich industrial solid waste

Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high silicon content waste is a potential raw material for the syn- thesis of silicon-based, multi-porous materials such as zeolites, mesoporous silica, glass-ceramics, and geopolymer foams. Representative sil- icon-rich industrial solid wastes (SRISWs) are the focus of this mini review of the processing and application of porous silicon materials with respect to the physical and chemical properties of the SRISW. The transformation methods of preparing porous materials from SRISWs are summarized, and their research status in micro-, meso-, and macro-scale porous materials are described. Possible problems in the application of SRISWs and in the preparation of functional porous materials are analyzed, and their development prospects are discussed. This review should provide a typical reference for the recycling and use of industrial solid wastes to develop sustainable “green materials.”

Organic Materials Could Improve the Phytoremediation Efficiency of Soil Potentially Hazardous Metal by Sedum alfredii Hance

Soil potentially hazardous metal(PHM)is continually attracting public attention worldwide,due to its highly toxic properties and potentially huge damage to human being through food chain.Phytoremediation is an effective and eco-friendly way in remediation technology.A pot experiment was carried out to investigate the effect of different organic materials(biogas residue(BR),mushroom residue(MR),and bamboo-shoot shell(BS))application on phytoremediation of two PHM-contaminated soils(Fuyang soil as‘heavily-polluted soil’and Wenzhou soil as‘moderately-polluted soil’,respectively)by Sedum alfrecdii Hance.The results indicated:1)for moderately-polluted soil,the 5%BR treatment had the strongest activation to Cu and Zn,for heavily-polluted soil,1%BS treatment had the highest activation effect for Cu,Zn,Pb and Cd.2)the above-ground biomass of Sedum alfredii Hance increased with the addition rate of organic materials.3)for Cd uptake of Sedum alfredii Hance in moderately-polluted soil,only 1%BS treatment had a better accumulation effect,compared to the control,for Zn element,MR treatments were weaker than the control,while other treatments were better than the control,of which 5%BR,1%BS and 5%BS accumulated more Zn element by 39.6%,32.6%and 23.8%,respectively;in heavily-polluted soil,the treatments of 5%BS,1%BR and 5%BR accumulated more Cd than the control by 12.9%,12.8%and 6.2%,respectively,the treatments with organic materials addition promoted Zn accumulation in shoots of Sedum alfredii Hance,and the best treatment was 5%BS.Therefore,an appropriate application rate of BS and BR could improve the remediation efficiency for Zn/Cd contaminated soils by Sedum alfredii Hance.

Improving thermal efficiency and stability of laser welding process for magnesium alloy by combining power modulation and subatmospheric pressure environment

The laser welding(LW)process of highly reflective materials presents low thermal efficiency and poor stability.To solve the problem,the effects of subatmospheric environment on LW process,technological parameters in subatmospheric environment on weld formation and welding with sinusoidal modulation of laser power on the stability of LW process in subatmospheric environment were explored.The AZ31magnesium(Mg)alloy was used as the test materials.The test result revealed that the weld penetration in subatmospheric environment can increase by more than ten times compared with that under normal pressure.After the keyhole depth greatly rises,significantly periodic local bulge is observed on the backwall surface of the keyhole and the position of the bulge shifts along the direction of the keyhole depth.Eventually,the hump-shaped surface morphology of the welded seam is formed;moreover,the weld width in local zones in the lower part of the welded seam remarkably grows.During LW in subatmospheric environment,the weld penetration can be further greatly increased through power modulation.Besides,power modulation can inhibit the occurrence of bulges in local zones on the backwall of the keyhole during LW in subatmospheric environment,thus further curbing the significant growth of the weld widths of hump-shaped welding beads and local zones in the lower part of welded seams.Finally,the mechanism of synchronously improving the thermal efficiency and stability of LW process of highly reflective materials through power modulation in subatmospheric environment was illustrated.This was conducted according to theoretical analysis of recoil pressure and observation results of dynamic behaviors of laser induced plasma clouds and keyholes in the molten pool through high speed photography.

Experimental Research on Toluene Degradation in Plasma as the Driving Force of Nanomaterials

Plasma technology has some shortcomings, such as higher energy consumption and byproducts produced in the reaction process. However non-thermal plasma associated with catalyst can resolve these problems. So this kind of technology was paid more and more attention to treat waste gas. In this paper, we make use of this technology to decompose toluene under different electric field and packed materials. At the same time, the mechanism of toluene decomposition using plasma and catalyst is discussed. The experimental results show toluene decomposition increases with electric field strength increasing and flow velocity and initial concentration decreasing. There are four conditions in plasma: without packed materials (1);with packed materials (2);with BaTiO3 in the surfaces of packed materials (3);and with nanometer Ba0.8Sr0.2Zr0.1Ti0.9O3 (4). Toluene decomposition represents a obvious trend, that is, η(4) > η(3) > η(2) > η(1). The best decomposition efficiency of toluene arrives at 95%.

Multi－diffused Reflection Spectroscopy of Rare Earths Doped LaOCl Powder Samples and the Calculation of Quantum Efficiency

The excitation and emission spectra, the relaxation time of principal spectral lines and multi-diffused reflection spectra in LaOCl: Er, LaOCl: Ho powder samples were measured. The diffused absorption spectrum was derived from the multi-diffused reflection spectrum. According to Judd-Ofelt theory,the intensity parameters, radiative transition probabilities and quantum efficiencies of luminescence emission were calculated. Then comparison with erbium and holmium doped floride glass and other matrices were made.

Charge Storage Properties of Aqueous Halide Supercapatteries with Activated Carbon and Graphene Nanoplatelets as Active Electrode Materials

Device level performance of aqueous halide supercapatteries fabricated with equal electrode mass of activated carbon or graphene nanoplatelets has been characterized.It was revealed that the surface oxygen groups in the graphitic structures of the nanoplatelets contributed toward a more enhanced charge storage capacity in bromide containing redox electrolytes.Moreover,the rate performance of the devices could be linked to the effect of the pore size of the carbons on the dynamics of the inactive alkali metal counterion of the redox halide salt.Additionally,the charge storage performance of aqueous halide supercapatteries with graphene nanoplatelets as the electrode material may be attributed to the combined effect of the porous structure on the dynamics of the non-active cations and a possible interaction of the Br^(-)/(Br_(2)+Br^(-)_(3))redox triple with the surface oxygen groups within the graphitic layer of the nanoplatelets.Generally,it has been shown that the surface groups and microstructure of electrode materials must be critically correlated with the redox electrolytes in the ongoing efforts to commercialize these devices.

Efficiency characterization of ceramic filtering materials used for drinking water treatment

For ceramic filtering materials, their adsorption capacities, purification efficiencies to remove organic compounds from drinking water, and correlation between adsorption capacities and pore structures were tested and analyzed. The results show that correlation coefficient between the specific surface area and the adsorptive amount of iodine molecule is 0.99; correlation coefficient between the pore volume and the adsorptive value of tannin molecule is 0.92, and correlation coefficient between the most probable diameter and the adsorption parameter is 1.0. A new method of morphology characterization for ceramic filtering materials was developed, which offered a sort of standard for the evaluation on water purification efficiencies and selection of ceramic filtering materials.

The Benefits of Integrated Methods in PV Making to Promote Their Efficiency and Achieve Low-Cost Modules

Active systems, such as solar thermal and photovoltaic offer a great potential in reducing of fuel energy consumption. To improve the sustainability of buildings, one of the challenges is to address the role of renewable energies. Today, the photovoltaic installations play an important role in creating solar renewable energy. They create 2000 MW electrical energy per year and its annual global sales grown to approximately 5.6 GWp. This paper presents a general overview on a serious effort to produce PV panels that could provide cheaper solar power. It also focuses on short background of PV. Furthermore, thin film technology benefits, the method of the most absorbing of solar spectrum and the method of solar concentration and the advantages of these systems are presented. Ultimately, a new high concentration PV power system will be assessed.

Graphene Oxide Application in Cement-Bound Materials-State of the Art

In recent years,the incorporation of nanoparticles in the cementitious matrix has been regarded as a prominent strategy in the research effort.This paper reviews the influences of the nanomaterial GO(graphene oxide)in cement bound materials,as GO has become one of the most well-known inclusion nanoparticles in the cementitious matrix in the last few years.This study describes(i)the influences of the GO on enhancing hydration mechanism in the cementitious materials;and(ii)the improved performance of the cementitious materials,which are highly dependent on the functionalizing behavior of the GO.All this improves the properties of the matrix.The paper reports the influences of GO on the workability of the mixtures and the durability enhancement of the cementitious composites.Therefore,it demonstrates promising results of employing GO in the fabrication of novel building materials.However,tremendous progress in utilizing GO in scientific domains like materials technology has achieved a significant level.Remarkable progress has been achieved by applying the GO in different fields such as solar cells and super capacitors.Hence,more intensive research is required to achieve comparable improvement in building materials which constitutes a significant future challenge.

Comprehensive reutilization of herbal waste:Coproduction of magnolol,honokiol,and β-amyrin from Magnolia officinalis residue

Herbal extraction residues(HERs)cause serious environmental pollution and resource waste.In this study,a novel green route was designed for the comprehensive reutilization of all components in HERs,taking Magnolia officinalis residues(MOR)as an example.The reluctant structure of MOR was first destroyed by alkali pretreatment to release the functional ingredients(magnolol and honokiol)originally remaining in MOR and to make MOR more accessible for hydrolysis.A metal–organic frame material MIL-101(Cr)with a maximum absorption capacity of 255.64 mg g^(-1)was synthesized to absorb the released honokiol and magnolol from the pretreated MOR solutions,and 40 g L^(-1)reducing sugars were obtained with 81.8%enzymatic hydrolysis rate at 10%MOR solid loading.Finally,382 mg L-1β-amyrin was produced from MOR hydrolysates by an engineered yeast strain.In total,1 kg honokiol,8 kg magnolol,and 7.64 kg β-amyrin could produce from 1 ton MOR by this cleaner process with a total economic output of 170,700 RMB.

Review of current progress in hole-transporting materials for perovskite solar cells

Recent advancements in perovskites’ application as a solar energy harvester have been astonishing. The power conversion efficiency(PCE) of perovskite solar cells(PSCs) is currently reaching parity(>25 percent), an accomplishment attained over past decades. PSCs are seen as perovskites sandwiched between an electron transporting material(ETM) and a hole transporting material(HTM). As a primary component of PSCs, HTM has been shown to have a considerable effect on solar energy harvesting, carrier extraction and transport, crystallization of perovskite, stability, and price. In PSCs, it is still necessary to use a HTM.While perovskites are capable of conducting holes, they are present in trace amounts, necessitating the use of an HTM layer for efficient charge extraction. In this review, we provide an understanding of the significant forms of HTM accessible(inorganic, polymeric and small molecule-based HTMs), to motivate further research and development of such materials. The identification of additional criteria suggests a significant challenge to high stability and affordability in PSC.

Axial response and material efficiency of tapered helical piles

Different techniques have been proposed to increase the bearing capacity of open-ended piles.Welding helices to the shaft and tapering the pile shaft could be used simultaneously to enhance the static and dynamic behaviors of these piles.This paper subjects the bearing capacity,stiffness,frictional behavior,and material efficiency of the tapered helical piles to scrutiny.Tapered helical piles are introduced herein as an alternative option to improve the material efficiency of hollow piles.Based on the Taguchi method,a series of experiments was designed and conducted.The axial responses of tapered helical piles are also investigated using finite element analyses.The results derived from loadedisplacement curves and strain gages are used to characterize the axial compression responses of tapered helical piles.The effects of tapered angle,helices diameter and helices distance are examined using dimensionless parameters,and the degree of contribution of these factors is calculated on each of the enumerated variables individually.Experimental results show that the shaft friction resistance of tapered helical piles increases continuously with the pile head settlement.Furthermore,the effect of tapered wall on the shaft friction resistance is more tangible at low stress levels.The results showed that the relative material efficiency factor of the optimum pile could be 2.5 times that of unoptimized pile with a similar quantity of material.

Analytical modeling of piezoelectric meta-beams with unidirectional circuit for broadband vibration attenuation

Broadband vibration attenuation is a challenging task in engineering since it is difficult to achieve low-frequency and broadband vibration control simultaneously.To solve this problem,this paper designs a piezoelectric meta-beam with unidirectional electric circuits,exhibiting promising broadband attenuation capabilities.An analytical model in a closed form for achieving the solution of unidirectional vibration transmission of the designed meta-beam is developed based on the state-space transfer function method.The method can analyze the forward and backward vibration transmission of the piezoelectric meta-beam in a unified manner,providing reliable dynamics solutions of the beam.The analytical results indicate that the meta-beam effectively reduces the unidirectional vibration across a broad low-frequency range,which is also verified by the solutions obtained from finite element analyses.The designed meta-beam and the proposed analytical method facilitate a comprehensive investigation into the distinctive unidirectional transmission behavior and superb broadband vibration attenuation performance.

Study on the influence of armature on the efficiency of reluctance accelerator

The armature is an important part affecting the energy conversion efficiency of a reluctance accelerator.In this paper,six kinds of soft magnetic materials are chosen and four structures are designed for the armature.At first,the circuit and magnetic force are theoretically analyzed.Then the armatures with different materials and structures are used in the simulation,and the performances are compared and analyzed.At last,the experiment verifies the theory analysis and simulation design.It is concluded that the saturation flux density and conductivity of the material are the key factors affecting the armature force,and the optimization of armature structure can effectively restrain the eddy current,reduce negative force and improve efficiency.Compared with cutting slits in solid armatures,laminating the sheets radially can reduce the eddy current more efficiently.Although slitting can prevent the eddy current to a certain extent,meanwhile,it will decrease the magnetic force because of the losing of magnetized volume and the surface area.Hence,choosing the high saturation flux density material and making out the armature with radially_laminated sheets will improve the efficiency of the reluctance accelerator.In this paper,the silicon steel radially_laminated armature is a better choice for the armature design of the reluctance accelerator.

Particular properties of Ti_2O and TiN_x nanoparticles prepared by thermal decomposition

Particular properties of Ti2O and TiNx prepared by thermal decomposition were introduced. A precursor prepared by titanium powder reacting with oxalate acid was thermally decomposed in nitrogen atmosphere at 840℃ for 15 min, and relatively pure Ti2O was then obtained. Conductive TiNx was also prepared after altering reaction conditions. Samples were characterized by resistivity, X-ray powder diffraction, transmission electron microscope, Ultraviolet-Visible diffuse reflection, and electromagnetic shielding efficiency. The results indicate that both Ti2O and TiNx have good conductivity. Moreover, Ti2O shows a better solar photocatalytic activity and TiNx does well in the electromagnetic shield.

Effects of polarization and p-type GaN resistivity on the spectral response of InGaN/GaN multiple quantum well solar cells

Effects of polarization and p-type GaN resistivity on the spectral response of InGaN/GaN multiple quantum well （MQW） solar cells are investigated. It is found that due to the reduction of piezoelectric polarization and the enhancement of tunneling transport of photo-generated carriers in MQWs, the external quantum efficiency （EQE） of the solar cells increases in a low energy spectral range （λ 〉 370 nm） when the barrier thickness value decreases from 15 nm to 7.5 nm. But the EQE decreases abruptly when the barrier thickness value decreases down to 3.75 nm. The reasons for these experimental results are analyzed. We are aware that the reduction of depletion width in MQW region, caused by the high resistivity of the p-type GaN layer may be the main reason for the abnormally low EQE value at long wavelengths （λ 〉 370 nm）.