Increasing Mass Ratio Research Articles

Experimental study on pigmented coatings using two particle types with complementary optical features

One effective measure for building energy reduction is to pigment coatings on building exteriors. Conventionally, most coatings are designed using single particle types. Due to the limited particle optical features, these coatings usually perform well in one performance (e.g., thermal aspect) but poorly in another (e.g., aesthetic aspect). Thus, in practice they may not be able to meet the user-required performance in both aspects. Using particles with complementary optical features, such requirements may be fulfilled. To this end, this study experimentally investigates double-layered coatings using two particle types (i.e., CuO and TiO2) with complementary features. The performance of 24 coating samples is evaluated with selected total particle masses and mass ratios. Results show that in comparison with the conventionally designed coatings, the two proposed ones (i.e., TiO2 - CuO and CuO - TiO2 coatings) provide more performance alternatives under varied mass ratios; and they also present significant performance differences. For instance, when the TiO2 mass ratio increases, the total solar reflectance of the CuO-TiO2 coating increases slowly at first but quickly afterwards; while that of the TiO2-CuO coating increases quickly in the beginning but experiences a slow increase afterwards. It also illustrates that as the same required performance is met, the final choice of the two coatings is mainly determined by the initial costs of the utilized particles. Considering the optimal design in practice, the proposed coating is modelled. Validation results are shown at last.

Vibration Analysis of Vessels Conveying Blood Flow Embedded in Viscous Fluid

Vibration analysis of vessels conveying blood flow embedded in viscous fluid is studied based on the modified strain gradient theory. The viscoelastic vessels are simulated as a non-classical Euler-Bernoulli beam theory. Employing Hamilton’s principle, the governing equations for size-dependent vessels are derived. The Galerkin method is used in order to transform the resulting equations into general eigenvalue equations. The effects of the blood flow profile and its modification factors, red blood cells (RBCs) and hematocrit are considered in the blood flow. Besides, the influences of the constitutional material gradient scale, blood flow, internal pressure, structural damping coefficient, viscous fluid substrate and various boundary conditions on the natural frequencies and critical buckling velocities are studied. It is revealed that as the hematocrit, fluid viscosity of substrate, internal pressure and mass ratio increase, the natural frequencies and critical buckling velocities decrease. Furthermore, the results indicated that the strain gradient theory predicts the highest natural frequencies and critical buckling velocities among others. The results are compared with those available in the literature and good agreement has been observed.

Seismic Isolation Performance Evaluation for a Class of Inerter-Based Low-Complexity Isolators

In this paper, the seismic base isolation problem for all low-complexity networks containing one inerter, one spring, and one damper is studied based on a multi-degree-of-freedom model. The analytical solutions for the H2 performance optimization are derived, and the traditional tuned mass damper (TMD) is employed for comparison. Extensive numerical simulations are performed to verify the effectiveness of the obtained results. The results show that for different seismic wave excitations, some isolators are better than TMD in controlling the displacement of the main structure. Moreover, with the increase of the TMD mass ratio, the isolation performances of the inerter-based isolators are increasingly better than that of TMD.

Preparation and mechanism of free‐radical/cationic hybrid photosensitive resin with high tensile strength for three‐dimensional printing applications

AbstractA ultraviolet (UV)‐curing free‐radical/cationic hybrid resin is designed and developed by blending epoxy resin with an acrylic resin, including N‐acryloyl morpholine, polyurethane acrylic ester (PUA), free‐radical and cationic photoinitiator. During UV‐curing, crosslinking locks the acrylate and epoxide polymers together through non‐covalent interaction. Most likely, the interpenetrating polymer network (IPN) structure can be generated in the three‐dimensional (3D)‐printed objects. The obtained results from Fourier transform infrared spectroscopy (FT‐IR) show that bisphenol A epoxy resin and acrylic resin are both successfully involved in the UV‐curing process. In addition, the effects of the mass ratio of epoxy to acrylic resin and the UV irradiation time on the properties of the hybrid resin are systematically investigated using liquid crystal display (LCD) 3D printers. It is found that the tensile strength of the hybrid resin increases in a certain range and the elongation at the break maintains an upward trend with the increasing mass ratio. Finally, it is found that the shrinkage of the hybrid resin also depends on the mass ratio of epoxy to acrylic resin, which decreases with the increase of the epoxy resin content in a certain range. Thus, herein we propose a feasible UV‐curing mechanism for the synthesis of hybrid resins for 3D printing applications.

Strength of Flocs Formed by the Complexation of Lysozyme with Leonardite Humic Acid.

Aggregation and aggregates properties of natural organic and nanosized macromolecules such as humic substances and proteins are crucial to explore so-called colloid-mediated transport and the fate of substances in soil and water environments. Therefore, the aggregation and dispersion, charging, and floc strength of lysozyme (LSZ)–leonardite humic acid (LHA) flocs were experimentally investigated. The experiments were performed in different salt concentrations and LSZ to LHA mass ratios as a function of pH. We obtained the stronger flocs at pH 4.4, where the isoelectric point (IEP) of the complex with the mass ratio 2.5 was confirmed. Thus, the aggregation of LSZ–LHA flocs is mainly caused by charge neutralization. We obtained the floc strength of 4.7 nN around IEP at low salt concentration of 3 mM, which was stronger than 2.8 nN in high salt concentration of 50 mM. The effect of salt concentration can be rationalized by charge-patch attraction at low salt concentration. With increasing mass ratio, the IEP shifted to higher pH. This is due to the increase in positive charge from LSZ in the mixture. The effect of the LSZ to LHA mass ratio on the maximum strength was weak in the range studied.

Experimental study on damping mechanism of buffered impact dampers

In this study, a shaking table test was performed to systematically explore the damping mechanism of buffered impact dampers. Parameters such as mass ratio, gap clearance, excitation characteristics and material properties were analyzed. Seven buffered materials were chosen in this study, and experiments on both buffered container and buffered particle were carried out. New concept “collision hardness” was proposed and further validated to evaluate how material properties affect the damping effect, which proved to be a vital index affecting momentum exchange, thus providing guidance for material selection. Results show that the damper’s reduction effect generally increases with the increase of mass ratio; the gap clearance should be moderate if a better reduction effect is expected; the optimal gap clearance is related to excitation characteristics. Damper with small collision hardness performs better, and the coefficient of restitution does not greatly affect the damping performance, because it reflects the coupled influences of momentum exchange and energy dissipation which counteracts with each other. In practical engineering, mass ratio is suggested to be considered before gap clearance in the design, and the damper with a hard particle and soft inner wall of the container is recommended.

Preparation of benzoxazine-modified halloysite nanotubes and its application on epoxy/benzoxazine composites

Benzoxazine monomer (named as B-aptes) was synthesized from 3-aminopropyltriethoxysilane (KH-550), bisphenol A (BPA), and paraformaldehyde. Subsequently, functionalized halloysite nanotubes were obtained by introducing B-aptes onto the surface of halloysite nanotubes (HNTs). Then, benzoxazine-modified halloysite nanotubes (B-HNTs) were used to combine with BPA epoxy resin to prepare the diglycidyl ether of bisphenol-A (DGEBA)/B-HNTs composites. The homogeneous dispersion state of modified HNTs in the cured composite matrix was observed by scanning electron microscopy. Differential scanning calorimetry was used to investigate polymerization behaviors of ternary composites. The results showed that the ternary composite possessed lower polymerization temperature compared with the neat DGEBA/benzoxazine. According to the results of thermogravimetric analysis, the thermal stability of DGEBA/benzoxazine copolymers was improved by the modified HNTs, the char yield increased with the increase of HNTs mass ratio. The results of mechanical tests and dynamic mechanical analysis displayed that the DGEBA/B-HNTs composites possessed promoted mechanical properties.

Extraction of Al and rare earths (Ce, Gd, Sc, Y) from red mud by aerobic and anaerobic bi-stage bioleaching

Red mud (RM) is a typical mass quantity of solid waste generated from industrial alumina production and usually consists of valuable metals such as Al and rare earths (REs). This work mainly investigated the extraction of Al and REs from RM via aerobic and anaerobic bi-stage bioleaching by Acidianus manzaensis with the addition of pyrite, by monitoring the morphology, phase and speciation transformations of Al, Si, S and Fe using primarily SEM-EDS, XRD, XPS, and XANES. The results showed that during the aerobic bioleaching stage with increase in mass ratios of pyrite/RM, the extraction rates of Al and REs increased; the highest rates for Al (85.1%), Ce (82.4%), Gd (86.8%), Y (85.3%) and Sc (78.6%) were achieved at pyrite/RM mass ratio 2:1 after 22 d of bioleaching. A slight decrease then occurred because that the complexes formed from jarosites, hematite, diaspore and SiO2-gel can adsorb small amounts of the dissolved elements. Under anaerobic conditions, the additive S0 gradually oxidized to sulfate, and the jarosites gradually dissolved into Fe2+ and disappeared at day 10 with maximal bioleaching rate for Al, Ce, Gd, Y and Sc as 52.5%, 86.3%, 93.7%, 90.2% and 74.9%, indicating that the residues from the first stage were dissolved with the dissimilatory reduction of jarosites by A. manzaensis using S0 as an electron donor. These results suggested a new method for the efficient recovery of valuable metals from RM.

Photochromism of photopolymerized novel copolymers having spirooxazine moiety groups

A novel class of photochromic copolymer based on spironaphthoxazine (SO) moieties was smoothly prepared through the copolymerization of methyl methacrylate (MMA), butyl acrylate (BA) and SO-based monomer by photopolymerization. Polymerization efficiency was studied by measuring the content of SO in eluents, which decreased with increasing mass ratio of SO in precursor monomer. The incorporated SO moieties endow the copolymers with remarkable photochromic ability. The novelty of this study is that unlike conventional physically blending photochromic polymer, SO moieties were chemically bonded with polymer chain, which is an effective way to prevent the SO from migration, thus increasing the stability and reliability during the long-term application. Moreover, the copolymerization was prepared through UV polymerization in the absence of organic solvent, which is environmentally friendly. Polymer chain flexibility can be well tuned by changing the mass ratio of BA. To make the copolymer more flexible, plasticizer of dibutyl phthalate (DBP) was also introduced. The photochromic ability of the as-prepared films was enhanced with increase in flexibility of polymer chain, which achieved the optimum state when the mass ratios of plasticizer DBP (dibutyl phthalate) and precursor BA (butyl methacrylate) were 20% and 50%, respectively. The thermal stability and tensile strength of the products were characterized by thermogravimetric analysis and electronic universal testing machine, which revealed that these copolymers could be applied as photochromic materials.

A novel strategy for the efficient decomposition of toxic sodium cyanate by hematite

Toxic sodium cyanate is always present in cyanide-contaminated waste. A new technology for the efficient decomposition of toxic sodium cyanate by hematite was first proposed in this study. The decomposition of sodium cyanate under various atmospheres has been studied. Studies show that sodium cyanate decomposes above 782 °C in Ar and above 627 °C in air. Sodium cyanate does not decompose even roasted at 400 °C for 120 min in air. Hematite does not promote the decomposition of sodium cyanate in Ar. However, almost all sodium cyanate decomposes efficiently at 400 °C and the mass ration of hematite to sodium cyanate of 1:1 for 30 min in air or oxygen atmosphere. The increased mass ratio of hematite to sodium cyanate and roasting temperature can both favor the efficient decomposition of sodium cyanate. The efficient decomposition of sodium cyanate occurs within 30 min, and it is almost stagnant with the prolongation of roasting time. When roasted in air or oxygen in the presence of hematite, sodium cyanate decomposes to Na2CO3, CO2 and N2 and a small amount of NaNO3 and NOx. The optimal efficient decomposition of sodium cyanate is to roast above 400 °C for 30 min in air or O2 at a mass ration of hematite to sodium cyanate greater than 1:1.

Multiple root resonance of tandem mill

The multiple-root resonance theory is introduced. The multiple-root resonance region is defined, and it includes the sub-multiple-root resonance region and complete-multiple-root resonance region. It is proved that the vibration mode shapes are identical if the natural frequencies are similar in size. The dynamic analysis of the 3-DOF model is investigated, and the results show that the variations of the mass ratio and stiffness ratio induce the natural frequencies approaching and forming a multiple-root resonance. The dynamic analysis of the tandem mill is made to study the multiple-root vibration, and the results show that with the increase in mass ratio, the 6th and 7th-order natural frequencies continue approaching one another and converge at the 5th-order natural frequency. The finite element analysis of the rolling mill shows that there are two similar natural frequencies in the rolling mill, and the vibration modes are not identical but have large vertical-component vibrations. The field test shows that the multiple-root resonance occurs in the tandem mill; after the foundation reconstruction, the multiple-root resonance is replaced by resonance with one dominant frequency, and the vibration is reduced.

Properties of Binary Mixture of Cetyl Diphenyl Ether Disulfonate and Linear Alkylbenzene Sulfonate

Abstract The surface properties of the binary mixture of cetyl diphenyl ether disulfonate (C16-MADS) and linear alkylbenzene sulfonate (LAS) have been investigated by salinity and hardness tolerance, equilibrium surface tension, wettability, foam and emulsification measurements. The results show that with increasing mass ratio of LAS in the C16-MADS/LAS mixed system, the ability to reduce the surface tension of the solution is improved. The wetting performance is also improved. The critical micelle concentration (CMC) values are increased first, then decreased, and are higher than the ideal CMC values, which indicates that there is an antagonistic effect that is not conducive to the formation of mixed micelles between C16-MADS and LAS. In addition, the C16-MADS/LAS system improves the hard water resistance of LAS and reduces the foam properties of LAS.

Synthesis of Grafted Cationic Starch with DMDAAC Using Ammonium Persulfate/Carbamide Initiation System

Using ammonium persulfate (APS)/carbamide initiation system, cationic grafted starch was prepared by the graft copolymerization of starch with diallydimethylammonium chloride (DMDAAC). The synthesized polymer was confirmed by FTIR, NMR, and XRD. And the morphology was characterized by SEM. The optimum conditions of graft copolymerization were determined and the flocculation properties of the cationic grafted starch were investigated using diatomite suspension. The obtained results showed that grafting ratio (G) and grafting efficiency (GE) have an increased trend along with the increase of mass ratio of starch to monomer. G, GE and cationic degree (DC) increased with the rise of mole ratio of AM to DMDAAC. When the total concentration of the monomers in the system is fixed, increasing APS concentration up to 0.33×10-3 M caused a rise for the G, GE and DC. The optimum temperature and the time were 40 °C and 5 h, respectively. The result also showed that the cationic grafted starch has excellent flocculation performance whether in acid, alkaline or neutral conditions.

Hard Carbon with Intensified Graphitization Induced By Graphene Oxide for High Initial Coulombic Efficiency Anode in Sodium Storage

Hard carbons hold the most promising practical application among all anode materials for sodium-ion batteries. However, the low initial Coulombic efficiency (ICE) limits their further commercialization. Herein, one kind of hard carbon with Intensified graphitization induced by graphene oxide was prepared by a new coupled carbonization strategy, in which the mixture of phenolic resin (PF) and grapheme oxide (GO) was heat-treated at high temperature directly. The as-prepared hard carbon exhibited outstanding electrochemical behaviors such as superior ICE. We also believe that the strategy may provide a constructive instruction for high performance hard carbon material designing.For synthesis of hard carbon (GHCs), GO aqueous suspension was first prepared via a modified Hummer’s method. Then PF was dissolved in the GO aqueous suspension (mass ratio of PF:GO was 50:1 to 200:1). The slurry was cured and dried at 120 °C, and further carbonized above 1000 °C.With increasing mass ratios of GO to PF, the interlayer distance of carbon decreased from 3.88 Å to 3.70 Å, less than 3.93 Å of pure PF, suggesting that the addition of graphene oxide may enhance the graphitization of PF derived carbon. La and Lc of GHCs also increased accordingly with the increasing of GO proportion, indicating the development of graphitic microcrystallite. C1s X-ray photoelectron spectra showed that, the sp2 C content of GHCs increased from 48.4% to 54.5%, which was several time larger than the pure contribution from physical addition of graphene theoretically (from 0.5% to 2%, corresponding to the mass ratio of PF:GO from 200:1 to 50:1 ). From HRTEM and SAED images, a significant improvement of short-range ordering degree can be clearly detected with the increasing of GO content. Those results were so consistent, indicating that GO gives an effcient induced local graphitization in hard carbon.The sodium storage performances of GHCs were characterized in a half cells with metal Na as the counter electrode, using 1.0 M NaPF6 in ethylene carbonate /dimethyl carbonate (1/1 in volume) as the electrolyte. As-prepared hard carbon delivered a superior ICE over 90%, high reversible capacity of 343 mAh/g and excellent cycling performance beyond 150 cycles with a capacity retention over 90%. This may be due to the characteristics of GHCs with less defective and lower surface area , especially with the Intensified local graphitization induced by graphene oxide. Figure 1

The Effect of Mass Ratio and Damping Coefficient on the Propulsion Performance of the Semi-Active Flapping Foil of the Wave Glider

A numerical investigation on the propulsion performance of the semi-active flapping foil of the wave glider with different mass ratio and damping coefficient is investigated. The commercial CFD software Fluent is used to solve the URANS equations around the flapping foil by the Finite Volume Method. A mesh of 2D NACA0012 foil with the Reynolds number Re = 42,000 is used in all simulations. We first analyze the effect of the mass ratio on the mean output power coefficient and propulsion efficiency and note that with the variation of the mass ratio, the propulsion efficiency decreases slightly. Besides, we find that the mass ratio has a noticeable influence on the mean output power coefficient, and the influence is determined by the reduced frequency. For high reduced frequency, with the increase of the mass ratio, the propulsion performance of the flapping foil decreases monotonously. For low reduced frequency, the mean output power increases slightly. For critically reduced frequency, the mean output power coefficient of the foil firstly increases and then decreases via the mass ratio increase. Then, we examine the influence of the damping coefficient on the propulsion performance of the flapping foil and find that the damping coefficient has a severe adverse effect on the output power and propulsion efficiency. We conclude that the influence of the damping coefficient should be considered first when we design the propulsion device of the semi-active flapping foil. Meanwhile, we should also consider the sea conditions to choose the mass ratio to optimize the flapping foil.

Experimental investigation of ethanol/diesel dual-fuel combustion in a heavy-duty diesel engine

Ethanol is a promising alternative fuel applicable in the internal combustion engine by virtue of its sustainability and soot-reducing potential. In this study, ethanol is injected into the intake port while diesel is directly injected into the cylinder of a heavy-duty diesel engine enabling dual-fuel operation. The main goals of the study are to probe the ethanol substitution ratio and load range and assess the resulting engine performance and emissions. Tests were performed with the original calibration at several loads using the European Stationary Cycle. The results show that ethanol mass ratios of up to 80% may be reached at low to medium loads without misfire. Addition of ethanol can reduce soot emissions, with no consistent effects on NOx emissions. As the ethanol mass ratio increases, dual-fuel operation suffers from incomplete combustion progressively. Increased HC and CO emissions are, however, believed to be manageable by a diesel oxidation catalyst at high loads. Both combustion and thermal efficiency decrease at low load when ethanol is introduced. However, thermal efficiency at medium load increases from 49.1% to 50%. For medium to high loads, thermal efficiency first increases to 50.7% and 49.7%, respectively, then decreases due to sub-optimal combustion phasing at high ethanol mass ratios. It is noteworthy that the pressure rise rate, ringing intensity, and peak pressure may appear to limit the ethanol ratio to below 40% for medium to high loads. However, this can be mitigated by delaying diesel injection timing, phasing the combustion later, without a large efficiency compromise.

Investigation on Ash-Fusion Characteristics of Livestock Manure and Low-Rank Coals

Large amounts of livestock manure are produced annually, and cogasification offers a promising method for large-scale and clean use of manure. To investigate the ash-fusion characteristics (AFC) of livestock manure and coal, and their variation mechanisms, the AFCs of two coals (Yima long-flame coal and Husheng lignite), two manures (cattle manure (CM), and swine manure (SM)), and their mixtures were explored. An increase in the ash mass ratio of the CM or SM increased the sintering temperature (Ts) of two mixed coal ashes (the SM enhanced the Ts more than that of the CM); however, their ash-fusion temperature (AFT) decreased first and then increased (the turning points for the Yima long-flame coal ash mixture were CM: ∼60% and SM: ∼40%, and those for the Husheng lignite were SM: ∼70% and SM: ∼50%). The Ts was induced by partial particle surface fusion, and was related to the formation of a low melting eutectic (e.g., binary systems for K2SiO3–Na2Si2O5 and Na2S–FeS) and their contents. The AFT indicated that the bulk melting property was determined mainly by ash composition, especially for a basic/acid ratio. The disappearance of mullite and the formation of high melting-point phosphates (e.g., KCaPO4, K2CaP2O7, and Ca2.71Mg0.27(PO4)2) resulted in AFT fluctuations of the mixtures.

Tobacco stem-derived N-enriched active carbon: efficient metal free catalyst for reduction of nitroarene

A series of N-enriched active carbons (NACs) were prepared from carbonization of tobacco stem with KOH as activating agent. The obtained NACs were used as efficient metal free catalysts for reduction of nitroarene. The results of N2 adsorption–desorption indicate that NACs have a large number of mesopores with the increase of mass ratio of KOH to the precursor. NACs-3800 has high surface area (SBET = 2938 m2 g−1) and a large pore volume (Vtotal = 1.60 cm3 g−1) with a nitrogen content (1.32%). NACs-3800 showed a high catalytic activity (99.9% conversion, nearly 100% selectivity to aniline) in the reduction of nitrobenzene. Moreover, NACs-3800 also exhibits good catalytic activity in the reduction of substituted nitroarenes. Furthermore, the NACs-3800 presented remarkable activity and durability for nitrobenzene reduction to the corresponding aniline. The recyclability of the catalyst and its cheap feedstock makes the overall process much simple, cost-efficient and environment-friendly.

Numerical Study of Static Instability of Pipe Conveying Incompressible Fluid under Different Boundary Conditions

In this article, the influences of uniform velocity profile, mass ratio, length and Winkler elastic foundation on the static instability of pipe conveying incompressible fluid are investigated. The Euler-Bernoulli beam theory is employed to derive partial differential equation of pipes carrying fluid. The results were carried out using ANSYS Workbench program, where the analysis is based on the numerical solution; using Finite element method to formulate both the pipe structure and fluid flow equations. The numerical approach is based on some research and analytical models. The natural frequencies of the system are attained with respect to different boundary conditions, such as pinned-pinned ends, clamped-pinned ends and clamped-clamped ends. The numerical results show satisfactory agreement with the theory of many aspects of the pipe dynamical carrying incompressible fluid were observed numerically such as, the increase in flow velocity, mass ratio and length reduced from the rigidity of the system and consequently the proper modes. Winkler elastic foundation has a stabilizing effect on the system.

Numerical Study of Static and Dynamic Instabilities of Pinned-Pinned Pipe under Different Parameters

In this study, the natural frequencies of the pipe transporting an fluid resting on an elastic Winkler-type and the critical velocities of instabilities are obtained by the standard finite element method. A dynamic characteristic of a pipe carrying internal fluid undergoes mechanical load due to inertia effect of fluid, Coriolis force, fluid kinetic force due to fluid flow velocity, dynamic load due to inertia effect on the pipe structure. A numerical modal analysis is realized in the fluid-structure interaction configuration. One dimensional beam finite element is used for investigating the dynamic behavior of the thin pipe. According to the approved method, the different elementary matrices were extracted, which were including to a code called Matlab. We developed a program under Matlab with R2017b version, where computations are in the complex planes. The initial approach is based on some research and analytical models. The numerical results show satisfactory agreement with the analytical results. The increase in flow velocity, mass ratio and length reduced from the rigidity of the system. Regions and range of instabilities are presented by numerical aspects. We determined the influence of the different parameters on the static and dynamic instabilities of the system.