Increasing Particle Diameter Research Articles

Migration and phase change phenomena and characteristics of molten salt leaked into soil porous system

Molten salt is important heat transfer and storage medium in various high temperature industrial systems, but its leakage and pollution have been seldom investigated. In this paper, migration and phase change phenomena and characteristics of molten salt leaked into soil porous system are numerically investigated using volume of fluid model. During the leakage stage, molten salt expands above the soil, migrates inside the soil and begins to solidify, and finally it solidifies as a solid layer during the post-leakage stage. The vertical velocity of molten salt inside the soil linearly decreases near the surface during the leakage stage, so molten salt gradually migrates into the soil, while the whole flow velocity rapidly approaches to zero after leakage. The temperature and heat flux in the soil near the surface both increase during the leakage stage, and then they decrease during the post-leakage stage. Because of solidification, there exist maximum migration radius and migration depth, so the environment pollution can be limited. As the inlet temperature rises, the maximum migration radius and migration depth both increase for low viscosity of molten salt, while the inlet velocity increment only increases the maximum migration radius. As the soil porosity or particle diameter increases, the maximum migration radius decreases, while the maximum migration depth increases.

Gellan microgels produced in planar microfluidic devices

Microgels were obtained from the droplets gelation of a water-in-oil emulsion containing gellan in the aqueous phase. Gellan gum (0.6% w/w) and calcium acetate (0.5 and 2.0% w/w) as gelling agent were used to produce the microgels. The effect of the continuous phase flow rate and salt concentration on the particle size and size polydispersity of the gellan microgels was evaluated, as well as microchannels configuration for encapsulation of hydrophilic compounds in these particles using planar microfluidics devices. The microgels exhibited uniform and spherical shape. A highly monodisperse particle size distribution was observed showing coefficient of variation below 5% and average size ranging from 63 to 113 μm. Increasing salt concentration caused an increase of the mean particle diameter and a decrease of the size polydispersity. However at high salt concentration the continuous flow rate did not exert significant effect on the microgel size since average size ranged from 106 to 113 μm. A potential use of gellan microgels as encapsulating matrix of active compounds was evaluated by adding a hydrophilic dye, Rhodamine B, in the aqueous phase. Results showed good retention capacity of the dye and stability over time of storage, indicating that microgels obtained by microfluidics technique may be used for the encapsulation of hydrophilic compounds, including those sensitive to temperature and pressure, as well as in drug delivery.

Electric agglomeration modes of coal-fired fly-ash particles with water droplet humidification

Electric agglomeration is a useful method to improve fly-ash particle collection efficiency in traditional electrostatic precipitators (ESPs) by increasing particle diameter and achieving particle pre-charging. In this study, a laboratory agglomerator, which consisted of a pre-charging region and a static mixer, was designed and tested for fine particle agglomeration. The pre-charging provided both positive and negative discharges in parallel channels. Fine water droplets were used to enhance particle agglomeration and collection efficiency in a downstream small ESP. The operating effects were evaluated under various applied voltages and droplet concentrations. Experimental results showed that the presence of water droplets effectively improved coal-fired particle agglomeration, pre-charging, and collection in the ESP. The total number collection efficiency improved from 53.91% to 86.02% compared with the condition without the agglomerator. In addition, a novel sampling method was used to observe agglomerated particles using scanning electron microscopy, and theoretical adhesive force analysis supported the proposal of a series of power-plant particle electric agglomeration modes.

Numerical study of fouling characteristics on two kinds of typical heat exchangers used in the waste heat recovery systems

The problem of high exhaust temperature universally exists around the industrial boilers, which causes enormous loss of energy. Different kinds of heat exchangers are widely used in the waste heat recovery systems to recover waste energy from different heat sources. However, considering the heat exchangers mainly work in dusty environment, such as in the tail of large boiler, fly ash fouling on heat exchangers is a major problem in waste heat recovery systems, which can lead to significant efficiency deterioration. Besides, the fouling may also lead to failure of the systems with serious economic consequence. The H-type finned tube heat exchanger is a new type of heat exchanger which have been widely used in waste heat recovery systems in recent years, because of their excellent anti-wear and anti-fouling performance. In this paper, a numerical model was developed to investigate the fouling characteristics of two kinds of H-type finned tube heat exchangers used in the waste heat recovery systems. Firstly, a fouling model which contains a deposition process and a removal process is developed. The deposition process is determined by the energy balance on the particles and the removal process is determined by the the local wall shear stress and the fouling thickness on the fin surface. As the flow field directly affects the particle motion, the fluid flow characteristics of the two kinds of heat exchangers are calculated, and the discrete phase model (DPM) was employed to trace the fly ash particles in the flow field during the fouling process. Since the simulation time is much smaller in magnitude than the real time in fouling process, it is impossible to simulate the whole real fouling time period (hours) with a small time step size. In order to obtain a reliable result, it is necessary to enlarge the simulation time and results to the real time scale. In this paper, a fouling time ratio is proposed by considering the volume difference between the simulated deposit layer and the real deposited particles and the concentration difference of injected particles between the simulation and real situation. According to the fouling time ratio, we can enlarge the simulation time and results to the real time scale. Then the real-time fouling characteristics of the two kind of H-type finned tube heat exchangers are investigated and the effects of inlet velocity, particle diameter on the fouling results are also studied. The results show that, the fouling mainly occurred in the flow stagnation region and the recirculation region of the H-type finned tube. The net fouling mass increases with the operating time, showing an asymptotic characteristic of growth, and finally will reach a stable value, which corresponds to the asymptotic fouling resistance. The increase in inlet velocity and particle diameter would lead to a rapidly decrease in fouling results. The anti-fouling performance of double H-type finned tubes shows slightly better than that of single ones, but the advantages decreases with the increase in inlet velocity and particle diameter.

Packing Efficiency Characterization of SiC Abrasive Machining Particles for Photovoltaic Silicon Wafer Slicing

Silicon Carbide (SiC) abrasive machining solid particulates is one of the key engineering materials in the continuous development of wafer technology. Analysis of its packing behaviour is important to ensure the highest quality in the ingot cutting process to produce silicon PV wafers. One of the parameters that is monitored is the amount of fine particles present during the cutting operation and the subsequent separation technologies to recycle the material to reduce cost and allow environmental sustainability. This study presents results showing that with increasing circularity, less fines remain in the slurry suspension which is expressed as the percentage of total volume of particles in the slurry mixture. Furthermore, the work has gathered that there is a strong relationship between the % fines removed and the average diameter of the particles. An analysis of the relationship between the actual % fines remaining as a function of particle diameter reveals that the % fines remaining decreases as the particle diameter increases and this behavior correlates well with a power law equation. This agrees with a model of the fishhook effect during particle separation in a mini-hydrocyclone expressed as an equation raised to the fourth power.

Computational fluid dynamics simulation of laboratory scale reactor of fast pyrolysis fluidised bed

Euler-Eulerian two-fluid model (EE-TFM), among the computational fluid dynamics (CFD) techniques and module available on the market, have been chosen to study and obtain the operational parameters required for the fluidisation of different materials and different particle diameters of the fluidised bed model. In the present work, the effect of the material, namely stainless steel and sand with the respective diameters of 0.5 and 1 mm have been investigated with the aid of ANSYS FLUENT 15. From the simulation, it has found that the minimum required superficial velocity of the driving gas for fluidisation of steel beads are 70 cm/s and 140 cm/s respectively for diameter of 0.5 and 1.0 mm. On the other hand, the minimum required superficial velocities to fluidise the less dense sand beads are 30 cm/s and 70 cm/s for particle diameter of 0.5 and 1.0 mm respectively. The results show that the minimum fluidisation velocity increases as the density of the particle material increases; while it also increases, when the particle diameter increases. It is concluded that the drag force required to fluidise the specific solid bead material is proportional to both the density and the diameter of the particle chosen.

In-situ observation of hydrophobic micron particle impaction on liquid surface

Particle impaction on a droplet surface directly affects the particle capture by the droplet, and this phenomenon is the basic process of wet scrubbing and wet deposition. The experimental system is established to in-situ observe the behavior of micron particles impacting on the liquid surface. 50–200μm hydrophobic PMMA and PS particles were used. The particles showed two types of motion behavior, namely, submergence and oscillation, after impaction onto the liquid surface. During particle sinking, the advancing contact angle remained constant. The shape of the liquid surface met the Young–Laplace equation under the quasi-static assumption. After the angle of the three-phase line reached the critical value, the liquid surface was closed, and the particle submerged. A small bubble formed, adhering to the particle trailing surface. If the particle velocity decreases to zero before the angle of the three-phase lines reaches the critical value, the particle will reverse the direction of its motion. When the particle moves to the horizontal liquid surface, the movement ceases. Reciprocating oscillation behavior was not observed. During particle reversion, the receding contact angle gradually decreased and then remained unchanged. The large contact angle hysteresis is the main cause of failure observation in rebound motion mode in the experiment. The changing rule of the critical submergence/oscillation velocity with the particle diameter and surface tension coefficient was studied. As the particle diameter increases, the critical submergence/oscillation velocity decreases. As the surface tension coefficient increases, the critical submergence/oscillation velocity increases. The observed critical submergence/oscillation velocity in this experiment demonstrated the accuracy of the proposed model.

입도분포를 고려한 석분 사용에 따른 시멘트 모르타르 성질의 변화 이해

이 연구에서는 고성능 시멘트 복합체의 잔골재 일부를 석분으로 대체하여 사용할 경우 재료의 성질 변화를 실험을 통해 살펴보았으며, 실험결과와 입도분포 특성과의 연관성을 여러 가지 모델들을 이용하여 분석하였다. 잔골재 중량 대비 0~30% 범위에서 석분을 치환한 시멘트 모르타르에 대해 유동성, 레올로지 특성, 강도 시험을 실시하였으며, 그 결과 석분 사용량이 증가함에 따라 유동성이 향상되고, 레올로지 정수(항복응력 및 소성점도)값이 감소하며, 압축강도 및 휨인장강도가 향상되는 것으로 나타났다. 이와 같은 실험결과는 모르타르를 구성하는 고체 입자들의 충전밀도와 밀접한 관련이 있으므로 최대 충전밀도를 얻기 위한 최적 입도분포 모델을 이용하여 그 영향을 분석하였다. 석분 사용량이 증가함에 따라 입자들의 입도분포가 최대 충전밀도를 얻기 위한 최적 입도분포에 더 가까워짐을 확인할 수 있었으며, 평균제곱근 오차를 이용하여 정량적으로 최적화 정도를 비교하였다. 석분 사용을 통한 입도분포 개선이 유동성의 향상과 소성점도의 감소, 그리고 강도의 향상에 미치는 영향은 관련한 여러 모델들을 이용하여 제시하였으며, 항복응력의 감소는 석분 사용에 따른 평균입경 크기의 증가와 관련이 있음을 보였다. This study investigates the properties of a high-performance cementitious composite with partial substitution of stone dust for fine aggregate. The relationship between the properties and particle size distribution was analyzed using several analytical models. Experiments were carried out to examine the flowability, rheology, and strength of cement mortars with different stone-dust replacement ratios of 0-30 wt.%. The results showed improved flowability, lower rheological parameters (yield stress and plastic viscosity), and improved strength as the amount of stone dust increased. These results are closely related to the packing density of the solid particles in the mortar. The effect was therefore estimated by introducing an optimum particle size distribution (PSD) model for maximum packing density. The PSD with a higher amount of stone dust was closer to the optimum PSD, and the optimization was quantified using RMSE. The improvement in the PSD by the stone dust was proven to affect the flowability, strength, and plastic viscosity based on several relevant analytical models. The reduction in yield stress is related to the increase of the average particle diameter when using stone dust.

Light Emission Intensities of Luminescent Y₂O₃:Eu and Gd₂O₃:Eu Particles of Various Sizes.

There is great technological interest in elucidating the effect of particle size on the luminescence efficiency of doped rare earth oxides. This study demonstrates unambiguously that there is a size effect and that it is not dependent on the calcination temperature. The Y2O3:Eu and Gd2O3:Eu particles used in this study were synthesized using wet chemistry to produce particles ranging in size between 7 nm and 326 nm and a commercially available phosphor. These particles were characterized using three excitation methods: UV light at 250 nm wavelength, electron beam at 10 kV, and X-rays generated at 100 kV. Regardless of the excitation source, it was found that with increasing particle diameter there is an increase in emitted light. Furthermore, dense particles emit more light than porous particles. These results can be explained by considering the larger surface area to volume ratio of the smallest particles and increased internal surface area of the pores found in the large particles. For the small particles, the additional surface area hosts adsorbates that lead to non-radiative recombination, and in the porous particles, the pore walls can quench fluorescence. This trend is valid across calcination temperatures and is evident when comparing particles from the same calcination temperature.

Thermal properties of nanofluids and their similarity criteria

We have experimentally studied how the Prandtl number (Pr) of a nanofluid depends on the concentration, size, and material of nanoparticles. The nanofluids were prepared using distilled water and nanoparticles of silica, alumina, titania, and zirconia. The volume concentration of particles was varied from 1 to 8% and their diameters changed from 10 to 150 nm. It is established that Pr values of nanofluids increase with the concentration of nanoparticles. The Prandtl number also significantly depends on the size of nanoparticles and decreases with increasing particle diameter.

Changes in low-density lipoprotein size phenotypes associate with changes in apolipoprotein C-III glycoforms after dietary interventions

The presence of small dense low-density lipoprotein (LDL) is associated with obesity, type II diabetes, and an increased risk for cardiovascular disease. Apolipoprotein C-III (apoC-III) is involved in the formation of small dense LDL, but the exact mechanisms are still not well defined. ApoC-III is a glycosylated apolipoprotein, with 3 major glycoforms: apoC-III0, apoC-III1, and apoC-III2 that contain 0, 1, or 2 molecules of sialic acid, respectively. In our previous work, we reported an association among apoC-III0 and apoC-III1, but not apoC-III2 with fasting plasma triglyceride levels in obesity and type II diabetes. The goal of this study was to determine the relationship between changes in the major apoC-III glycoforms and small dense LDL levels after dietary interventions. Mass spectrometric immunoassay was performed on fasting plasma samples from 61 subjects who underwent either a high-carbohydrate diet (n=34) or a weight loss intervention (n=27). After both dietary interventions, changes in total apoC-III concentrations were associatedwith changes in LDL peak particle diameter (r=-0.58, P<.0001). Increases in total apoC-III concentrations after the high-carbohydrate diet were associated with decreases in LDL size (r=-0.53, P=.001), and decreases in apoC-III concentrations after weight loss were associated with increases in LDL peak particle diameter (r=-0.54, P=.004). Changes in concentrations of apoC-III1 and apoC-III0, but not apoC-III2, were associated with changes in LDL peak particle diameter in both the weight loss and high-carbohydrate interventions. We conclude that apoC-III0 and apoC-III1, but not apoC-III2 are associated with the formation of small dense LDL.

Study on gas-particle heat transfer in oscillating flows

A numerical study of the gas-particle cluster interphase heat transfer in oscillating flows is conducted by using the one-dimensional Eulerian-Eulerian model. The effects of flow oscillation on the two-phase flow, particle concentration and as well the interphase heat transfer rate are investigated. The results show that the heat transfer between the gas and particle clusters can lead to the increases of the average particle concentration and the corresponding oscillation amplitude, but the decrease of the oscillation wavelength, which are closely related to the interphase heat transfer during the particle velocity relaxation process. Convective particle clustering is the primary cause of the oscillation of the two-phase mixture equilibrium temperature. Particle initial velocity and gas inlet velocity have great influences on the particle concentration and temperature. Increases in the gas inlet mean velocity and oscillation frequency are beneficial for the reduction in particle and gas temperature oscillation amplitudes. Particle diameter has an insignificant influence on the averaged values of the two-phase equilibrium mixture parameters but a noted impact on the oscillation amplitude of particle concentration. The increase in particle diameter is helpful for the reduction of the oscillation amplitude of the two-phase mixture equilibrium temperature.

Nano- and microparticles of gelled oil combining aminoacid-based low molecular weight organogelators and nonionic amphiphilic polysaccharides

Nano- and microparticles of gelled oils were prepared using an aminoacid-based low molecular weight organogelator and amphiphilic nonionic polysaccharides as stabilizers. The investigated oils were Tetralin, M810N and M829. The preparation procedure involved organogelator dissolution in hot solvent (150–190°C) followed by oil-in-water emulsification at 70–80°C in liquid state and final cooling step to room temperature to obtain gelled oil particles. The range of particle diameters (sub-micrometric or micrometric) could be adjusted by selecting the emulsification process, sonication or vortex mixing. Using sonication, organogel particles could be also prepared at room temperature with the oil phase in the gel form. The suspensions of gelled oil particles could be centrifuged and fully redispersed by vortex mixing with an increase of particle diameters whose extent depended on the nature of the oil.

Influence analysis for the behavior of dewaterability of excess sludge in a two-stage vermifilter.

To improve excess sludge dewaterability, a two-stage vermifilter was developed to qualitatively and quantitatively analyze sludge physico-chemical properties (fractal dimension, zeta potential, extracellular polymeric substances (EPS), particle size distribution, etc.) and to correlate them with sludge dewatering characteristics (specific resistance to filtration (SRF) and capillary suction time (CST)). Results demonstrated that sludge dewatering performance was significantly improved after the primary vermifilter VF1 and the second-stage vermifilter VF2. In addition, the further VF2 treatment exhibited higher effects on sludge dewatering performance. The particle boundary of sludge after VF2 treatment was clearer and smoother than VF1 sludge (VF1S), apart from the fact that sludge morphological structure got denser and more compact. Comparing with VF1S, the fractal dimension D1 calculated within 1D topological space was closer to 1 after VF2 treatment, and the fractal dimension D2 within 2D topological space closer to 2, indicating a better dewatering performance after VF2 treatment. Additionally, the changes of sludge floc surface properties (such as zeta potential and EPS) resulted in small particles agglomerating into larger ones and then the increase of particle diameter. In summary, the two-stage vermifilter got a better sludge dewatering performance, and thus beneficial for subsequent processing of sludge.

Migration of variable density proppant particles in hydraulic fracture in coal-bed methane reservoir

The well performance in Coal-Bed Methane (CBM) reservoir is highly dependent on the conductivity of hydraulic fracture created to increase well production rate and contact area with the reservoir. Aimed at improving the effective fracture length of hydraulic fracture in CBM reservoir and the seam proppant concentration, the objective of this paper is to investigate the migration of variable density proppant particles in hydraulic fracture and seams using numerical modeling and simulation. In the proposed model, the interaction among fracture proppant particles distributed in a pseudo fluid model is taken into consideration. Comparison between the model calculation and field radioactive tracing logging interpretation shows that the proposed model is accurate and reliable in applications. Additionally, we carried out the sensitivity study on the viscosity of fracking fluid, fracture area, proppant density, injection rate and other factors. It is shown that, with the condition of a confining pressure of 69 MPa and an ambient temperature of 90 °C, the crush value of nutshell proppant is less than 2%, which meets the field application requirements. Furthermore, with the increase of both fracturing fluid viscosity and injection rate, the propped effective fracture length increases, and lead to a more uniform distribution of proppants. The increase in proppant particle diameter, inversely, results in a decrease in the effective fracture length. As for variable-density proppant, the effective crack support length would be longer than the single ceramic proppant, and the particle distribution of the case with variable density is more uniform.

Cadmium underpotential deposition on CdSe and CdS quantum dot films: size dependent underpotential shift

Underpotential deposition of cadmium from aqueous solution of cadmium salt (0.1M Na2SO4+10mM CdSO4, pH 4) was examined by cyclic voltammetry and potentiodynamic electrochemical impedance spectroscopy on сhemical bath deposited CdSe and CdS quantum dot (QD) film electrodes. QD size was thermally controlled during CdSe film deposition and the post-synthesis thermal treatment of CdS QDs in Ar gas medium. The increase of the substrate particle diameter from few nm to almost bulk dimensions resulted in a positive shift of the upd starting potential by approx. 0.2V. The discovered size effect showed some similarity with the size effects reported in literature for metal upd on metal, thus indicating the general nature of the upd control by substrate particle size on different types of substrates. However, the size effects in cadmium upd on cadmium chalcogenides were observed at smaller particles than those in metal upd on metal particles.

Facile Fabrication of High‐Density Sub‐1‐nm Gaps from Au Nanoparticle Monolayers as Reproducible SERS Substrates

The fabrication of ultrasmall nanogaps (sub‐1 nm) with high density is of significant interest and importance in physics, chemistry, life science, materials science, surface science, nanotechnology, and environmental engineering. However, it remains a challenge to generate uncovered and clean sub‐1‐nm gaps with high density and uniform reproducibility. Here, a facile and low‐cost approach is demonstrated for the fabrication of high‐density sub‐1‐nm gaps from Au nanoparticle monolayers as reproducible surface‐enhanced Raman scattering (SERS) substrates. Au nanoparticles with larger diameters possess lower surface charge, thus the obtained large‐area nanoparticle monolayer generates a high‐density of sub‐1‐nm gaps. In addition, a remarkable SERS performance with a 1011 magnitude for the Raman enhancement is achieved for 120 nm Au nanoparticle monolayers due to the dramatic increase in the electromagnetic field enhancement when the obtained gap is smaller than 0.5 nm. The Au nanoparticle monolayer is also transferred onto a stretchable PDMS substrate and the structural stability and reproducibility of the high‐density sub‐1‐nm gaps in Au monolayer films are illustrated. The resultant Au nanoparticle monolayer substrates with an increasing particle diameter exhibit tunable plasmonic properties, which control the plasmon‐enhanced photocatalytic efficiency for the dimerization of p‐aminothiophenol. The findings reported here offer a new opportunity for expanding the SERS application.

Real-time fouling characteristics of a typical heat exchanger used in the waste heat recovery systems

A numerical method was developed to investigate the fouling characteristics of a typical heat exchanger. Firstly, an integrated fouling model which consists of a deposition process and a removal process was developed to simulate the fouling characteristics. The deposition criterion was determined by the energy balance during the interaction of particle and surface, and the removal process was based on the local wall shear stress and the fouling thickness. Then, the fluid flow characteristics were calculated and the discrete phase model (DPM) was employed to trace the fly ash particles during the fouling process. Since the simulation time is much smaller in magnitude than the real time in fouling process, a fouling time ratio was proposed to enlarge the simulation time and results to the real time scale. The flow characteristics, real-time fouling characteristics and the effects of inlet velocity, particle diameter on the fouling resistance were investigated. At last, the comparison with experimental results was also conducted. The results show that the particle motion was easily controlled by different vortex structures and the fouling mainly occurred in the flow stagnation region and the recirculation region. The net fouling results shows an asymptotic characteristic of growth and the increase in inlet velocity and particle diameter would lead to a decrease in fouling results.

Reaction characteristics of KOH-modified copper manganese oxides catalysts for low-temperature CO oxidation in the presence of CO2

Binary copper manganese oxides catalysts supported on different activated carbons were prepared using the co-precipitation and high-pressure impregnation methods. The catalysts were further modified by KOH to mitigate the adverse effect of CO2 on their CO oxidation performances. The as-synthesized catalysts were characterized by N2 adsorption–desorption, X-ray diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. The effects of support and synthesis method, CO concentration, CO2 concentration, gas hourly space velocity (GHSV), and particle size on CO oxidation performances of the catalysts were investigated. The nature of the different activated carbon supports showed no significant effect on their CO oxidation performances. By contrast, the high-pressure impregnation method was conducive to more effective loading and uniform dispersion of the active components on the support and therefore to benefit the catalyst enhanced CO oxidation performances. Under the given experimental conditions, CO oxidation conversion decreased with the increase of CO concentration, CO2 concentration, GHSV, and particle diameter.

Investigation of Thermal Conductivity and Viscosity of Al2O3/Water Nanofluids Using Full Factorial Design and Utility Concept

In the present study, the effect of particle concentration, particle diameter and temperature on the thermal conductivity and viscosity of Al2O3/water nanofluids was investigated experimentally using design of experiment approach (full factorial design). Variables were selected at two levels each: particle concentration (0.1–1%), particle diameter (20–40[Formula: see text]nm) and temperature (10–40[Formula: see text]C). It was observed that the thermal conductivity of the Al2O3/water nanofluids increases with increasing concentration and temperature and decreases with increase in particle diameter, while viscosity increases with increasing particle diameter. Results showed that the interaction effect of concentration and temperature also has significant effect on the thermal conductivity of Al2O3/water nanofluids. For viscosity, the interaction of particle diameter and temperature was important. Utility concept was used to optimize the properties collectively for better heat transfer performance. The optimal combination for high thermal conductivity and low viscosity was obtained at higher level of particle concentration (1%), lower level of particle diameter (20[Formula: see text]nm) and higher level of temperature (40[Formula: see text]C). At this condition the increment in thermal conductivity and viscosity compared to base fluid was 11.51% and 6.37%, respectively.