Grinding Periods Research Articles

CO2 capture using red mud & mechanically-activated red mud and its kinetics under ambient conditions

Greenhouse gas emissions and the growing stockpiles of red mud, an alkaline industrial waste with potential for CO2 sequestration, present significant environmental challenges. This article aims to enhance the CO2 sequestration capacity of red mud by mechanically activating its surface using a high-energy planetary ball mill for extended grinding periods. The novelty of the study lies in investigating the CO2 sequestration capacity and evaluating its kinetics includingadsorption and desorption on feed and mechanically-activated red mud under atmospheric temperature and pressure for the first time via a direct gas–solid carbonation route using a fixed bed column. The effect of ball size (10,8 and 6 mm) used in high-energy planetary ball mills while mechanical activation, CO2 flow rate (20–80 ml/min), and reaction time (1–5 h) on the CO2 capture has been studied. Apart from this, experimental data on CO2 sequestered (1–5 h) and the extent of CO2 desorption (7–35 days) are fitted to various kinetic models, including pseudo-first-order, pseudo-second-order, and Avrami’s fractional order models. Results showed that the CO2 sequestration capacity of feed red mud is 3.75 mg/g, while the capacity of mechanically-activated red mud increased to 18.28 mg/g, with an adsorption time of 5 h at ambient temperature and pressure. The most suitable fit is attained with Avrami’s fractional order model, suggesting that both physisorption and chemisorption contribute to enhancing the CO2 sequestration capacity of red mud. The mechanism for this process has also been proposed along with the suitable characterizations.

Suitability of Using LA Abrasion Machine for the Nano Manufacturing of Palm Oil Fuel Ash and Incorporating in Mortar Mixture

Background In order to enhance the properties of palm oil fuel ash-based mortar, researchers have explored the concept of reducing palm oil fuel ash (POFA) to a nanoscale. While previous studies have utilized ball milling machines with high grinding speed to achieve nano-scale POFA, the Los Angeles abrasion machine, which is more readily available and has a slower grinding speed, has been rarely employed. Objective The study aimed to investigate the suitability of using a Los Angeles abrasion machine with a low grinding speed to produce nano palm oil fuel ash. This paper also provides a comparison of the effect of using the nano POFA with different particle sizes within the range of 982 to 150 nm on the mortar’s flowability and compressive strength. Methods To produce nano-size palm oil fuel ash using the Los Angeles abrasion machine, the received palm oil fuel ash was thermally treated and ground using a Los Angeles abrasion machine with varying grinding periods. The grinding process parameters were kept constant, but second grinding periods of 50,000, 80,000, and 110,000 cycles were introduced. All three types of nano palm oil fuel ash were analyzed for their physical properties, chemical properties, morphology, and mineralogy. Furthermore, these nano palm oil fuel ashes were incorporated into a designed mortar mix along with micro palm oil fuel ash. The mortar’s fresh properties and compressive strength at different curing ages were observed and analyzed. The relationship between various factors, such as the replacement rate of micro, nano palm oil fuel ash, the grinding cycles of nano POFA, and the corresponding responses, specifically the compressive strength at different curing ages, was analyzed and explained using the response surface methodology. Results The 110k cycle nano palm oil fuel ash had a smaller particle size of 103.1 nm, while a particle size of 529 nm and 325 nm was found in the 50k and 80k cycle nano palm oil fuel ash. In terms of the combination of micro and nano palm oil fuel ash in the mortar, increasing the dosage of nano palm oil fuel ash contributed to improvements in flow diameter and compressive strength. However, the opposite trend was observed with micro palm oil fuel ash. The optimal mix design for the combination involved using 10% micro and 2 to 3% nano palm oil fuel ash. This composition led to an improvement rate of 7.9%, 1.48%, and 4.6% in compressive strength at 7, 28, and 90 days, respectively. While, the response surface methodology’s numerical optimization also supported the use of a similar combination. However, it additionally recommended employing the 50,000-cycle nano palm oil fuel ash in the mortar for earlier curing stages, while the 110,000-cycle nano palm oil fuel ash was suggested for later curing stages. Conclusion Los Angeles abrasion machine could be utilized to produce nano palm oil fuel ash with a particle size up to 103 nm with the aid of designed parameters. In this mortar mix design, the impact of a small variance in nano palm oil fuel ash’s particle size was trivial compared to the replacement rate of micro palm oil fuel ash on the mortar’s compressive strength.

Characterisation of Ground Coal Bottom Ash With Different Grinding Times

The physical and chemical composition of Ground Coal Bottom Ash (GCBA) exposed to varying grinding periods is discussed in this article. CBA was pulverised for 20 hours, 30 hours, and 40 hours in a ball mill machine. Particle Size Analyzer (PSA) and X-ray Fluorescence (XRF) instrument were used to characterise GCBA. According to the results of the tests, GCBA with a grinding duration of 40 hours generates the largest percentage of the finest particle (50-1000 nm) at 4%, the specific surface area is 13528.18 cm2/cm3, and the specific gravity (SG) is 2.54. According to the XRF results, there are no significant variations in the chemical compositions of the CBA with varying grinding periods. At 20, 30, and 40 hours grinding time, the primary oxide element for SiO2 is 51.5%, 53.8%, and 52.3%, while Al2O3 is 14.3%, 15.1%, and 14.6%, and Fe2O3 is 5.08%, 5.27%, and 5.07% respectively. The sum of three primary oxide constituents surpasses the 70% ASTM C618 limit for pozzolanic material Class F fly ash.

Modeling of Bauxite Ore Wet Milling for the Improvement of Process and Energy Efficiency

Size reduction is a necessary operation in mineral processing plants and provides the desired size for separation operations and the liberation of the valuable minerals present in ores. Estimations on energy consumption indicate that milling consumes more than 50 % of the total energy used in mining operations. Despite the fact that ball milling is an efficient operation, it is energy intensive, and its modeling is a great challenge. In the present experimental study, efforts are made to model wet milling of bauxite ores and identify the optimum material filling volume in the ball mill. Modeling is based on the characterization of the grinding products obtained after various grinding periods and the description of the particle size distributions using mathematical approaches, i.e., Gates–Gaudin–Schuhmann (GGS), Rosin–Rammler (RR), and logistic distributions. In addition, grinding kinetic models were applied to the experimental data in order to identify if the linear theory of the population balance model is valid during bauxite grinding. The experimental data revealed that the logistic distribution is a model that represents more reliably particle size distributions obtained after grinding and fits the experimental data better than the GGS and RR models. Regarding grinding kinetic analysis, it was found that grinding exhibits non-first-order behavior and the reduction rate of each size is time dependent. This experimental work is in line with the Sustainable Development Goal of UN, SDG12: Responsible Consumption and Production and aims to improve the efficiency of ore grinding and thus reduce energy requirements and the associated CO2 emissions.

Compressive Strength, Wear, and Structure Characteristics as a Result of Silicon Carbide Addition on a Copper Base

The current research aims to study of the effected of the reinforced materials on the extent of failure or resistance of the metals. The powder method was used to manufacture models of copper-based composites, then copper was reinforced by silicon carbide at percentages of (0,5,10,15,20)%, and alumina was used as a fixed support at (10% Al2O3), Moreover, the mixture was ground by a steel mill for 2, 4, and 6 hours and then pressed with a press capacity of 20 tons. The homogeneous mixture was placed inside a steel mold and pressed at 5 tons for a time of one minute. After sintering at 900°C for two hours, the samples were prepared. The diagonal compressive strength tests, the wear test and examination of an atomic force microscope in three different grinding periods were carried out. The results of the examination showed that the highest compressive strength was obtained (53.3 Mpa) at a six-hour grinding time with a percentage of 20%SiC, while the wear rate showed a decrease in its value as it was less weary at a six-hour grinding time, and at a percentage of 20%SiC also (1.10368 * 10 -7 g/cm). The images obtained from the atomic force microscope showed that the total surface topography and the morphology of the grains formed on the surface have a high degree of homogeneity and arrangement after the heat treatment. We observed the regularity in the growth of the superimposed layer and noted that the grains were arranged perpendicular to the axis. As the crystalline heights are approximately equal, the best characteristic parameters of the results were found at sintering of 900°C, grinding time of six hours, and cementing content of 20%.

THE EFFECTS OF BALL SIZE ON THE DETERMINATION OF BREAKAGE PARAMETERS OF NEPHELINE SYENITE

In this study, the changes in the specific rate of breakage and breakage distribution function of the nepheline syenite sample were investigated by using alloy steel ball in five different sizes. Specific rate of breakage and breakage distribution function values were obtained from the particle size distributions acquired after the grinding periods. As a result of grinding tests, an increase in rate of breakage is observed due to the increase in ball diameter.

Grinding Kinetics of Slag and Effect of Final Particle Size on the Compressive Strength of Alkali Activated Materials

This study aims to model grinding of a Polish ferronickel slag and evaluate the particle size distributions (PSDs) of the products obtained after different grinding times. Then, selected products were alkali activated in order to investigate the effect of particle size on the compressive strength of the produced alkali activated materials (AAMs). Other parameters affecting alkali activation, i.e., temperature, curing, and ageing time were also examined. Among the different mathematical models used to simulate the particle size distribution, Rosin–Rammler (RR) was found to be the most suitable. When piecewise regression analysis was applied to experimental data it was found that the particle size distribution of the slag products exhibits multifractal character. In addition, grinding of slag exhibits non-first-order behavior and the reduction rate of each size is time dependent. The grinding rate and consequently the grinding efficiency increases when the particle size increases, but drops sharply near zero after prolonged grinding periods. Regarding alkali activation, it is deduced that among the parameters studied, particle size (and the respective specific surface area) of the raw slag product and curing temperature have the most noticeable impact on the compressive strength of the produced AAMs.

Effects of Grinding Process on the Properties of the Coal Bottom Ash and Cement Paste

The grinding process is necessary to convert original coal bottom ash (CBA) into a powder form. The aim of this study is to evaluate the grinding process effects on physical properties of CBA, it influences on consistency and setting time of cement paste and to predict it potentiality based on chemical characteristics to reduce the alkali-silica reaction (ASR) in concrete. The CBA is the by-product of coal based thermal power plant. Due to high production of electricity in Malaysia, the excess amount of CBA has been produced annually and it causes the environmental problems. Therefore, it is necessary to come up with advanced solutions for that pollution. This study considered the different grinding periods i.e. 2, 10, 20, and 40hrs as to produce different particle fineness. It was perceived through the laboratory findings that the more the grinding period, finer the particle sizes. Besides that, cement paste with 10, 20 and 30% of ground CBA as a substitute of ordinary portland cement (OPC) by weight was prepared, it was observed that the consistency of OPC paste increases with the addition of ground CBA. Moreover, initial and final setting time of cement paste containing ground CBA was observed higher than the OPC paste. Hence, based on experimental analysis and energy efficiency scenario, grinding period of 20hrs with specific surface area 3835.75 cm2/g is suggested for the future studies.

Impact of Grinding Procedure on the Yield and Quality of the Extract from Clove Buds Using Supercritical Fluid Extraction

Introduction: The effects of the grinding procedure on the supercritical fluid extraction (SFE) yields of eugenol, β-caryophyllene, α-humulene, and eugenyl acetate from clove are discussed in detail in this paper. Methods: For this purpose, five grinding procedures were employed: 1) continuous 1-min grinding, 2) continuous 2-min grinding, 3) two 1-min grinding periods with 6-min stop in between 4) continuous 4-min grinding, and 5) four 1-min grinding periods with 6-min stops in between. After that, the extractor was filled with 12 g of milled clove obtained using one of the grinding procedures while the other SFE parameters were kept constant (pressure of 150 bar, temperature of 40 °C, supercritical CO2 flow rate of 1.03×10−4 kg/s, static time of 20 min, and dynamic extraction time of 15 min). Then, the composition of the extract was evaluated by gas chromatography (GC). Conclusion: It was found that the grinding procedure has considerable effects on the recoveries of eugenol, β-caryophyllene, α-humulene, and eugenyl acetate from clove, and employing four 1-min grinding periods with 6-min stops in between as the grinding procedure gave the highest content of the aforementioned components in the extract.

Unexpected electrocatalytic activity of the milled mixture containing PdCl2 and multi-walled carbon nanotubes towards ethanol oxidation reaction

A novel finding, that the ground mixture containing PdCl2 and multi-walled carbon nanotubes (MWCNTs) (denoted as PdCl2/MWCNTs) has an unexpected electrocatalytic activity towards ethanol oxidation reaction (EOR), is reported for the first time in this work. The influence of grinding periods on the properties of the resultant PdCl2/MWCNTs mixture is preliminarily investigated. The resultant samples are thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD results indicate that although the crystallinities of the prepared samples decrease with increasing the grinding period, no novel phase is displayed in the prepared samples. The electrocatalytic activity of the resultant samples for EOR is studied by using cyclic voltammetry (CV) and chronoamperometry (CA). And it is revealed that the electrocatalytic activity of the resulting mixture for EOR is closely related to the grinding period and the best electrocatalytic activity towards EOR is exhibited by the 15 min-ground mixture. The work described in this work provides a novel concept that the ground mixture containing palladium salts and MWCNTs can also be employed as electrocatalysts for EOR.

The Investigation of Grindability of Refractory Wastes in Their Recycling

The ceramic industry is one that stands out in the use of industrial tailings, replacing pure raw materials by some of these materials. Refractory wastes are ground and used in certain proportions in refractory production. This study is aimed at determining the grindability of recycling of refractory wastes and their kinetic behavior. The breakage behaviors were determined experimentally by using the mono-size fraction technique. The mono-size samples of –2360 + 1700 μm, –1180 + 850 μm, and –425 + 300 μm were ground batchwise for the selected periods to determine the Si. At the end of each grinding period, using the material at different mono-size groups, we determined the particle size distributions and breakage behaviors of the products. Depending on the grinding periods in both of the mills, energy consumption and d80 values of grinding products obtained by various grinding periods were determined. It was found that as the size group decreases, the breakage speed decreases in the ball mill and increases in the stirred mill. An increase in the grinding period results in an increase in energy consumption, but there is no significant change in d80 size in grinding of refractory waste in the ball mill. However, it was found that d80 size decreases significantly with increasing grinding period in the stirred mill.

The investigation of breakage kinetics of vitrified sanitary ware wastes in laboratory scale ball and stirred mills

ABSTRACTThis study is aimed to determine the grindability and kinetic behavior on grinding of vitrified sanitary ware wastes. The specific rates of breakage (Si) and the model parameters were determined through kinetic experiments to understand the grinding mechanisms of vitrified wastes. The breakage behaviors were determined experimentally by using mono-size fraction technique. The mono-sized samples of −2360 + 1700 µm, −1180 + 850 µm, and −425 + 300 µm were ground batchwise for the selected periods to determine the Si. At the end of each grinding period, using the material at different mono-size groups, particle size distributions and breakage behaviors of the products were determined. Depending on the grinding periods in both of the mills, energy consumptions and d80 values of grinding products obtained by varying grinding periods were determined. It was acquired that as the size group decreases breakage speed gets slower in the ball mill and increases in the stirred mill. An increase in the grinding period results in an increase in energy consumption, but there is no significant change in d80 size in grinding of vitrified waste in the ball mill. However, it was found that d80 size significantly decreases depending on the increasing grinding period in the stirred mill.

Mesoporous structure and pozzolanic reactivity of rice husk ash in cementitious system

The present study assessed the effects of grinding on the rice husk ash (RHA) microstructure, specific surface area (SSA), pore volume and water absorption capacity. The pozzolanic reactivity of RHA subjected to different grinding periods and of silica fume (SF) has been evaluated by determination of the accelerated pozzolanic strength reactivity index in mortar and the portlandite content in cement pastes. RHA samples contain macro- and mesopores. Grinding partly collapses the porous structure of RHA and reduces SSA. There is an optimum grinding time/fineness of RHA for maximum compressive strength. Despite having a higher SSA, RHA consumes less portlandite but induces similar mortar compressive strength compared to SF. Because of the mesoporous structure, ground RHA can absorb an amount of aqueous phase to decrease the effective water content. Moreover, calcium ions have access to internal surface of RHA particles, enhancing the pozzolanic reactivity of RHA.

A Simulation Study of Laboratory Scale Ball and Vertical Stirred Mills

AbstractThe aim of this study was to investigate the grindability of solid fossil fuels from a thermal power plant by using a vertical stirred mill and conventional ball mill. The solid fossil fuel sample was obtained from the Zonguldak Catalagzi thermal power plant in Turkey. The sample below 3350 μm (d80 = 2100 μm) was ground in the laboratory scale stirred mill and ball mill. The d80 sizes of the products at the end of grinding periods of 0.25, 0.50, 1 and 4 min in the stirred mill were determined as 190, 102, 78 and 28 μm, respectively. For this purpose, the stirred mill was used at a stirring speed of 360 rpm and with a 6 mm diameter ball. In the ball mill, the d80 sizes of product after 1, 4, 8, 12 and 24 min of grinding were determined as 1802, 1130, 324, 167 and 81 μm, respectively. The results indicated that grinding by means of a stirred mill was much more efficient than grinding with a ball mill in terms of size distribution of the products. The energy consumption of the product with d80 = 78 μm was obtained as 10.53 kWh/t after 1 min of grinding time in the laboratory scale stirred mill. In the same manner, the energy consumption of product with d80 = 81 μm by using the laboratory scale ball mill was 72.73 kWh/t after 24 min of grinding. It can be clearly seen that the d80 size of the fossil fuel reduced from 2100 μm to 1130 μm after a 4 min grinding period in the ball mill grinding tests. However, the d80 size of the solid fossil fuel reduced to 28 μm after the same grinding time in the stirred mill and it was also possible to efficiently obtain size reduction below 100 μm. However, the ball mill grinding process cannot provide this efficient size reduction for longer grinding times. The ball mill grinding experimental results and simulation results showed that they were fairly consistent with each other. The simulation of higher speed mills such as pin type stirrers has been extensively investigated for relatively small‐scale applications by JKSimMet. In this study, the JKSimMet software package was adapted for a stirred mill with the help of the base model of ball milling.

Grinding kinetics of amorphous powder obtained by sol–gel process

Pre-mullite powder has been synthesized by sol–gel process followed by calcination. Aluminium nitrate and tetraethyl ortosilicate (TEOS) were used as the starting materials. X-ray diffraction (XRD) analysis showed that calcined pre-mullite powder is completely amorphous. The powders were wet milled in planetary ball-mill within various time intervals. The particle size distribution of ground samples has been determined using particle size analyzer (PSA). The powder samples morphology was investigated with Scanning Electron Microscopy (SEM). Comminution kinetics of calcined pre-mullite gel is modeled using a classical batch grinding equation based on selection and breakage functions. The analytical solution of the batch grinding equation, as well as parameters of grinding kinetics was obtained through Nakajima and Tanaka approach. Analysis of experimental data resulted with model suitable for prediction of particle size distribution of calcined amorphous gel comminuted in planetary ball mill. Model is suitable if the duration of grinding is no longer than 128 min. Obtained product size distribution, for shorter grinding duration (≤ 128 min) is consistent with massive fracture mechanism. For longer grinding periods (≥ 256 min) changes of breakage mechanism indicated parallel fracture and attrition mechanism. The parameters of grinding kinetics obtained by the linear regression analysis were used to reproduce the product size distributions. The good agreement between experimental and calculated size distributions confirms the applicability of the applied rate equation to the description of grinding of calcined amorphous gel.

The Effect of Grinding Media Shape on the Specific Rate of Breakage

AbstractThe effect of the shape of grinding media on the breakage parameters of colemanite has been investigated in kinetic studies. In this present research, three different monosize fractions, i.e., – 425 + 300 μm, – 300 + 212 μm and – 212 + 150 μm, were used. The grinding media used for the tests were 36.5 × 36.5, 30.1 × 30.1, 25.4 × 25.4, 19.05 × 19.05 and 12.7 × 12.7 mm diameter cylinders, and 36.5, 30.1, 25.4, 19.05 and 12.7 mm diameter balls made from cast iron. The specific rate of breakage (Si) and model parameters (aT, α) were evaluated for the same quantity of cylinders, balls and feed material. The values of Si and the model parameters indicated that a faster breakage rate can be obtained by using cylinders as the grinding media. The size distributions of the products showed that the use of cylinders for grinding offers advantages for relatively coarse feeds. At shorter grinding periods, the product fineness from cylinder grinding was greater than that from ball grinding. However, after progressive grinding, the product fineness of ball grinding eventually exceeded that of cylinder grinding. The overall results indicated that the shape of the grinding media plays a determining role in the overall process.

Loose abrasive edge wear effects and final surface topography in conventional grinding machines

Applying Cordero-Davila's edge ring pressure increase to upper disk kinematics equations has led to excellent agreement between theoretical loose abrasive wear computer simulations and their experimental counterparts. Experiments to verify Cordero's ring equations over long grinding periods, up to 40 min, and their computer simulations are presented in detail. These experiments led to a new improved version of Kumanin's loose abrasive wear equation. Maximum wear rate and final topography errors, between theory and experiment, were slightly larger than instrumental uncertainty. Now it became possible to compute exact pressure, relative speed and wear, at any contacting point pair and over the entire upper free disk surface.

Maximizing wear resistance of balls for grinding of coal

A Brazilian power plant consumes mineral coal with high ash contents to feed four turbines to generate 450 MW. Four ball mills, 4.2 m in diameter, are fed with crushed coal to deliver the material ground to sizes less than 0.075 μm. High wear rates were observed when using forged high-carbon steel balls. A pilot-plant ball mill, with a 0.01 m 3 chamber, was used to perform wear tests, comparing the original ball material and seven grades of high chromium cast irons, grinding the same coal as used in the industrial plant. Test pieces were 60-mm balls with different chemical compositions and heat treatments. Balls were weighed after 10-h grinding periods, for up to 7 periods. The mass losses were converted to equivalent diameter losses and regression straight lines were obtained, showing the wear rates of the materials. The wear rates of the cast irons with 25–30% Cr were only 10–20% of the wear rate of the forged steel. Cast irons with 15–18% Cr wore at around 50% of the rate of the steel. Analyses of the coal ashes showed around 40% of quartz as 10–20 μm particles. Examination of the surface of worn balls showed that these particles caused the wear.

Reduction kinetics of mechanically activated hematite concentrate with hydrogen gas using nonisothermal methods

The reduction kinetics of both non-activated and mechanically activated hematite concentrate in a vibratory mill for different grinding periods have been studied using themogravimetry (TG). Changes in the structure of hematite were studied using X-ray diffraction analysis. The isoconversional method of Kissinger–Akahira–Sunose (KAS) was used to determine the activation energy of the different reactions. The Vyazovkin model-free kinetic method was also used for prediction of kinetic behavior of the samples for a given temperature. Fe 2O 3 was found to reduce to Fe in a two-step via Fe 3O 4. Intensive grinding resulted in improved resolution of overlapping reduction events. It was also established that the mechanical activation had a positive effect on the first step of reduction. With increasing the grinding time, the activation energy at lower extent of conversion ( α ≤ 0.11) decreased from 166 to 106 kJ mol −1 range in the initial sample to about 102–70 kJ mol −1 in the sample ground for 9 h. The complexity of the reduction of hematite to magnetite and magnetite to iron was illustrated by the dependence of E on the extent of conversion, α(0.02 ≤ α ≤ 0.95). The values of E decreased sharply with α for 0.02 ≤ α ≤ 0.11 range in the initial sample and mechanically activated samples, followed by a slight decrease in the values of E during further reduction by α ≤ 0.85 in the ground samples up to 3 h. A slight increasing dependence of E on α for mechanically activated sample within 9 h in the second step of reduction was observed due to the finely agglomerated particles during intensive milling and subsequently the formation of a dense layer during the reduction processes. In addition, the dependence of ln A α on α was detected and it was found that the ln A α shows the same dependence on α as the apparent activation energies.

The effect of anionic dispersants on grindability of different rank coals

The effect of PSS (Sodium Polystyrene Sulphonate) and NSF (Naphthalene Sulphonate Formaldehyde Condensate) chemicals used to control the pulp rheology on the grindability of coals was studied. Zonguldak region bituminous coal and Istanbul region brown coal samples that high and low rank were used. Wet grinding tests with two coal samples were performed with or without PSS and NSF under constant grinding conditions: solid ratios ranged from 50% to 60% with 0–60 min grinding periods. In the present study, grinding conditions of coal with high pulp solid ratio were improved through the lowering of the viscosity of the coal by using the dispersing agents, PSS and NSF, during the grinding stage and evaluation were made by using the “efficiency factor”. It is possible to increase the amount of finely ground bituminous coal from Zonguldak by 20% and 16%, if optimum concentrations of PSS (0.3%) and NSF (0.7%) are used, respectively. Whereas, the increase in the case of finely ground lignite from Istanbul was 32% and 20%, respectively.