Study of the Kinetics of Copper Extraction with (anti)-2-Hydroxy-5-nonylbenzophenone Oxime Using a Rotating Diffusion Cell

Abstract

A rotating diffusion cell was used to study the chemical reaction in which copper is transferred from an aqueous sulfate phase to an organic phase containing a copper-complexing agent (purified anti-2-hydroxy-5-nonylbenzo-phenone oxime) dissolved in n-decane. A mathematical model was developed to describe the contributions of the kinetic and diffusive resistances to the overall resistance to mass transfer. Application of this model to the experimental data enabled an overall rate equation for the reversible copper extraction reaction to be written. The active oxime species in the extraction reaction was found to be the monomer with first-order kinetics. The extraction reaction rate was also found to be dependent on aqueous phase hydrogen ion concentration with negative first-order kinetics. The extraction rate constant was determined as 1.3 × 10^?5 cm/s. Assumption that the reverse rate is dependent on hydrogen ion concentration with first-order kinetics enabled the reverse rate constant to be calculated as 6.8 × 10^?3 cm⁴/mol·s.     

Demonstration of the CPMA-Electrometer System for Calibrating Black Carbon Particulate Mass Instruments

In an effort to improve regulations for particulate emissions from aircraft engines, the Aircraft Exhaust Emissions Measurement Committee, SAE E-31, is investigating instruments to measure black carbon mass concentration in real time. The current candidates are a laser-induced incandescence instrument (LII 300) and a photo-acoustic Micro-Soot Sensor (MSS). However, both of these instruments use indirect techniques, measuring parameters other than the actual mass of particulate in the exhaust, and therefore require calibration. Previously, it has been shown that a centrifugal particle mass analyzer (CPMA) can be used in conjunction with an aerosol electrometer to traceably generate an aerosol with known mass concentration. This system can be used to rapidly calibrate particle mass instruments (on the order of minutes), without the time-consuming process of filter sampling, which is often used for calibration and prone to sampling artifacts. Here, we demonstrate the feasibility of the CPMA-electrometer system for calibrating two LII 300 instruments and two MSS instruments, which were calibrated to the NIOSH 5040 standard. The correlations between the CPMA-electrometer system and the challenge instrument were highly linear for both the LII and the MSS, and agreed well with the previous calibration. All four instruments were found to correlate with the CPMA-electrometer system with R² values of 0.993 to 0.999. The standard uncertainty in the CPMA-electrometer system averaged 4.3% and was as low as 2.6% for some measurements. With a simple improvement to the aerosol electrometer, we estimate this average uncertainty would be less than 3%. This lower uncertainty and much higher speed of measurement support the use of the CPMA-electrometer system as a mass measurement calibration method for black carbon instruments.

Copyright 2015 American Association for Aerosol Research     

Cure kinetics,glass transition temperature development,and dielectric spectroscopy of a low temperature cure epoxy/amine system

This article reports a study of the chemical cure kinetics and the development of glass transition temperature of a low temperature (40°C) curing epoxy system (MY 750/HY 5922). Differential scanning calorimetry, temperature modulated differential scanning calorimetry, and dielectric spectroscopy were utilized to characterize the curing reaction and the development of the cross‐linking network. A phenomenological model based on a double autocatalytic chemical kinetics expression was developed to simulate the cure kinetics behavior of the system, while the dependence of the glass transition temperature on the degree of cure was found to be described adequately by the Di Benedetto equation. The resulting cure kinetics showed good agreement with the experimental data under both dynamic and isothermal heating conditions with an average error in reaction rate of less than 2 × 10^?3 min^?1. A comparison of the dielectric response of the resin with cure kinetics showed a close correspondence between the imaginary impedance maximum and the calorimetric progress of reaction. Thus, it is demonstrated that cure kinetics modeling and monitoring procedures developed for aerospace grade epoxies are fully applicable to the study of low temperature curing epoxy resins. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Phosphate uptake from water on a Surfactant-Modified Zeolite and Ca-zeolites

The phosphate adsorption kinetics are determined in batch-wise (noted B) and fixed-bed column (noted C) experiments on a Surfactant-Modified Zeolite (SMZ) and various Ca-zeolites. The influence of phosphate concentration (0.08 or 0.8?mmol/L), presence of NO₃ ^?, HCO₃ ^?, SO₄ ^2? and Cl^? competing anions (individual concentration?=?0.8?meq/L) and flow rate Q (1?C30?mL/min) is studied. Preliminary experiments lead to the selection of the most efficient Ca-LTA and SMZ samples for the subsequent studies. In B experiments, the nature of the used system does not influence the equilibrium removal rate R (??80%) but affects the adsorption kinetics. The equilibrium times are shorter on SMZ than on Ca-LTA, increasing with the phosphate concentration and the presence of competing anions, respectively in the ~0.5?C6 or ~3?C24?h ranges. In C experiments, the phosphate uptake performances on SMZ are higher than in the corresponding B experiments, with in particular higher final q/q_m values. The deterioration of the performances on SMZ in presence of competing anions or with increase of Q is due to the effect of the slow phosphate ion-exchange kinetics and the short used contact time. For similar reasons, sorption on Ca-LTA is lower than on SMZ. For instance, with a 0.8?mmol/L phosphate concentration and a 10?mL/min flow rate, the time-decreasing R values become close to 50 and 10% after filtration of 10 bed-volumes respectively in presence of SMZ and Ca-LTA. Globally, SMZ is clearly more efficient than Ca-LTA, being furthermore a versatile and easily regenerable material.     

Stratospheric Aerosol Sampling: Effect of a Blunt-Body Housing on Inlet Sampling Characteristics

During a campaign to study ozone loss mechanisms in the Arctic stratosphere (SOLVE), several instruments on NASA's ER-2 aircraft observed a very low number density (0.1 I^?1) of large, nitric-acid-containing particles that form the polar stratospheric clouds (PSCs). For effective physical and chemical characterization of these particles, the measurements from these instruments have to be intercompared and integrated. In particular, proper interpretation requires knowledge of the sampling characteristics of the particles into the instruments. Here, we present the calculation of the sampling characteristics of the one of the instruments on the ER-2, the NOAA NOy instrument. This instrument sampled ambient particles and gas from two forward-facing inlets located fore and aft on a particle-separation housing (the football) and measured total NOy in the sample. In recent studies, ambient aerosol mass has been estimated by the difference of the measurements of the two inlets with the assumption that the rear inlet observations represent the gas-phase NOy and small particles and the front inlet samples represent gas-phase NOy and all particle sizes with varied efficiency (anisokinetic sampling). This knowledge was derived largely from semiempirical relations and potential flow studies of the housing. In our study, we used CFD simulations to model the compressible flow conditions and considered noncontinuum effects in calculating particle trajectories. Our simulations show that the blunt body housing the inlets has a strong and complex interaction with the flow and particles sampled by the two inlets. The simulations show that the front inlet characteristics are influenced by the effect of the blunt body on the upstream pressure field. The rear inlet sampling characteristics are influenced both by the shape and size of the inlet and its location on the blunt body. These interactions result in calculated inlet characteristics that are significantly different from previously assumed values. Analysis of the SOLVE data, considering the ambient conditions and the calculated inlet sampling characteristics, in conjunction with thermodynamic growth modeling of super-cooled ternary solution (STS) particles, provides validation of the CFD results.     

Comparison of a Quadrupole and a Time-of-Flight Aerosol Mass Spectrometer during the Feldberg Aerosol Characterization Experiment 2004

The Feldberg Aerosol Characterization Experiment (FACE-2004) took place from July 13–August 4, 2004 at the Taunus Observatory on the “Kleiner Feldberg” (825 m a.m.s.l.) in Central Germany. The experiment included (amongst others) size-resolved chemical characterization of non-refractory aerosol components. One of the experiment's objectives was to better understand and to characterize recently developed aerosol measurement instrumentation by intercomparison with other co-located instruments. One of these instruments was the Aerodyne Time-of-Flight Aerosol Mass Spectrometer (ToF-AMS).

Here we compare the datasets obtained by the ToF-AMS with those obtained by the well-characterized co-located Quadrupole Aerosol Mass Spectrometer (Q-AMS). A good agreement between the recently developed ToF-AMS with the established Q-AMS is reported here for all species measured with the two instruments for a time period where both instruments operated under well-calibrated conditions. During measurements with reduced detector gain after a pump failure changed species concentrations were measured with the ToF-AMS that did not agree with those measured with the Q-AMS. These changes were different for the individual species and could be attributed to the influence of the ion detection threshold as was shown by model calculations.

For efficient and user-friendly processing of ToF-AMS raw data a data processing software package was developed. Since this is the first time this software was used for field data, it is described in some detail here.     

Determination of the activation energy and intrinsic rate constant of methane gas hydrate decomposition

Experimental data on the kinetics of methane gas hydrate decomposition are reported. The isothermal/isobaric semi‐batch stirred‐tank reactor, used by Kim et al. (1987), was modified to include an on‐line particle size analyzer. The experiments were conducted at temperatures ranging from 274.65 K to 281.15 K and at pressures between 3.1 and 6.1 MPa. The model of Clarke and Bishnoi (1999, 2000) was used to determine the intrinsic rate constant. It was found that the activation energy for methane hydrate decomposition is 81 kJ/mol and the intrinsic rate constant of decomposition is 3.6 × 10⁴ mol/m² Pa.s.     

Kinetics of reactions between chlorine or bromine and the herbicides diuron and isoproturon

The chemical oxidation of two herbicide derivatives of the phenylurea group—diuron and isoproturon—has been carried out by means of chlorine, in the absence and in the presence of bromide ion. Apparent second‐order rate constants for the reactions between chlorine and the herbicides were determined to be below 0.45 L mol^?1 s^?1. Hypobromous acid reacts faster with the investigated herbicides, especially with isoproturon (k_app = 24.8 L mol^?1 s^?1 at pH 7). While pH exerts a negative effect on the bromination rate, the maximum chlorination rate was found to be at circumneutral pH. In a second stage, the oxidation of each compound was conducted in different natural waters, in order to simulate the processes which take place in water purification plants. Again, chlorine was used as an oxidant, and bromide ion was added in some experiments with the aim of producing the more reactive HOBr oxidant. The herbicide oxidation rate was inversely proportional to the organic matter content of the natural water. However, the formation of trihalomethanes (THMs) was directly proportional to the organic matter content and constitutes a limitation for the application of chlorine during drinking water treatment. Finally, the evolution of herbicide concentration was modeled and predicted by applying a kinetics approach based on the rate constants for the reactions between the herbicides and the active oxidants. Copyright © 2007 Society of Chemical Industry     

Influence of transport effects on pyrolysis reaction of coal at high heating rates

The kinetics of coal pyrolysis may be influenced either by chemical reaction or by transport processes, the latter becoming rate-determining at increasing heating rate, particle size and pressure. Quantitative data are reported for those parameters which cause pyrolysis to become transport-controlled. The experiments have been performed with three different coals in H₂ and N₂, at heating rates ranging from 10³ to 10⁴ K s^?1, pressure from 0.1 to 150 bar and particle size from 0.063 to 0.8 mm.     

How Bromate and Ozone Concentrations Can be Modeled at Full-Scale Based on Lab-Scale Experiments – A Case Study

This article presents a full-scale modeling study of an industrial ozonation unit for practical application. The modeling framework combines an integrated hydraulic model (systematic network) with a quasi-mechanistic chemical model. Dealing with natural water, the chemical model has to be parameterized, and the parameters calibrated. This was done based on lab-scale experiments. The calibration results showed that the chemical model is able to account for changes in contact time with ozone, pH, temperature, ozone dose, NOM concentration, bromide concentration. Comparison of residence time distributions showed that the hydraulic model accurately reproduces flow conditions. Six sampling points were installed along an industrial ozonation unit of 487 m³ consisting of two baffled tanks in series. Bromate and ozone concentrations were monitored under varying operational process conditions. After the selection of a value for the k_La, simulations were run. Using the lab-scale calibrated models, simulated and experimental data were found in close agreement: 84% of the simulated concentrations for ozone matched measurements (±experimental error), 60 % for bromate. A readjustment of the kinetics of a single reaction (out of 65) showed that seasonal changes in NOM activity may easily be taken into account based on regular concentration measurements (90% of the bromate concentrations were then modeled accurately).     

Mass Transfer Rate with Liquid Ion Exchangers. The Role of Interfacial Chemical Reactions in the Extraction Kinetics by Dinonylnaphthalenesulphonic Acid and Trilaurylammonium Salts

Kinetics and interfacial tension studies concerning the liquid cation exchanger dinonylnaphthalene sulphonic acid (HD) and the liquid anion exchangers trilauryl-ammonium chloride and nitrate (TLAHCI and TLAHNO₃), performed in the laboratory, are reviewed. The interfacial tension studies have shown that, due to the very strong surface active properties of these compounds, even at very low bulk organic concentrations, the interfacial plane gets completely saturated with a strongly adsorbed monomolecular layer of the exchanger. The structure of the interface is such that the ion-exchange group faces the aqueous phase while its organic part is completely immersed in the organic diluent. Extraction kinetic experiments performed with a quiescent interface cell (Lewis cell) as a function of the stirring speed, interfacial area and volume of the phases have shown that (a) a region always exists where the extraction kinetics is independent of the stirring speed and (b) the exchange kinetics is directly proportional to the interfacial area and inversely proportional to the volume of the phases. These two facts, together with the knowledge of the interfacial structure of the exchanger, are a strong indication that interfacial chemical reactions can have a predominant effect in determining the extraction kinetics. Experiments performed at relatively high stirring speeds of the phase as functions of the chemical composition of the system have produced a set of interfacial chemical reactions which completely describe the kinetics of the liquid ion-exchange process. This set of reactions consists basically of the following steps: (a) formation of an interfacial complex between the interfacially adsorbed molecules of ion-exchanger and the metal cation or complex present in the aqueous solution, (b) replacement at the interface of the interfacial complex with bulk organic molecules of the ion-exchanger; this process, with a rate which is proportional to the organic concentration of the exchanger, occurs through the reaction with bulk molecules of the extractant, and (c) the reverse steps occur when organic to water transfer takes place. By applying the stationary condition to the interfacial complex its concentration has been evaluated and a rate expression derived which has led to the calculation of the rate constants of the chemical reactions. The following metal ions have been studied experimentally: Fe+³, Eu+³, Ce+³, Gd+³, Tm+³ with HD; FeCln³-n with TLAHCI and Pu(NO₃)n⁴-n with TLAHNO₃. By using the derived rate expressions and rate constants, distribution laws have been obtained to calculate equilibrium distribution data in good agreement with experimental results.     

Determination of the biogenic and fossil organic matter content of refuse-derived fuels based on elementary analyses

A method to determine the mass, energy and carbon content of biogenic and fossil matter in refuse-derived fuel (RDF) is described. The method combines standard chemical information about biogenic and fossil material with data from a chemical analysis of the RDF. The data are used to solve a set of equations that deliver the mathematically and statistically derived final result. For the chemical analysis representative samples of the RDF were assessed in a CHNSO elemental analyser. The proposed method was validated by characterizing defined reference mixtures of plastics and biomass (e.g., polyethylene and cardboard). The correlation coefficient (r²) between the measured and reference values was greater than 0.99. If representative sampling of RDF is assumed, the new method represents a reliable, quick and complementary method for characterizing RDF.     

Numerical analysis of a reactive extrusion process. Part I: Kinetics study on grafting of vinylsilane to polyethylene

For controlling a reactive extrusion process in the subsequent study. the model equations of reaction kinetics and shear viscosity were studied. We focused on a free radical reaction between the molten polyethylene and vinylsilane. The kinetics model was expressed as a reaction rate equation with an apparent rate constant. The shear dependent of reacted polyethylene was formulated by employing the modified Cross model proposed in our early study. In addition, the average molecular weight was considered to correlate the shear viscosity with the reaction kinetics, leading to a series of rheo‐kinetics formulas. The experiments were carried out in a specific batch mixer suitably designed for sampling in arbitrary periods. Their reaction conversions, molecular weight distributions, and shear viscosity were measured, respectively, with an induced coupled plasma (ICP) emission spectrochemical analyzer, a high temperature gel permeation chromatography (GPC), and a capillary rheometer. Determining the parameters in each model, a simulator is set to investigate an engineering extrusion process.     

Performance Comparison of Scanning Electrical Mobility Spectrometers

Scanning electrical mobility spectrometers (SEMS) are commonly used for near real-time ultrafine particle size distribution measurements. Analysis of SEMS measurements to calculate particle size distributions requires detailed understanding of instrument characteristics and operation. Varying instrument designs are used in the different commercial SEMS systems, and data analysis with these instruments requires accurate knowledge of their relative performance. In this study, an experimental approach to evaluate and reconcile differences between different SEMS instruments is established. This approach is used to characterize the relative performance of two SEMS systems—TSI's SMPS 3936-L22 and MSP's WPS XP1000—for particle sizes in the range of 20 to 300 nm. In these tests, the instruments were operated under a low flowrate condition with aerosol and sheath air flows of 0.3 and 3 LPM, respectively. Measurements show that the particle sizing characteristics of the instruments are very consistent with each other over the entire range of particle sizes studied. Particle number characteristics are dependent on the treatment of particle losses in the system and accounting of non-idealities of transfer function. The number concentrations reported by two instruments are generally consistent with each other and with an upstream reference counter for particle sizes larger than ～ 90 nm. For smaller particles, the low flowrate operation of the two systems results in significant penetration losses. A net particle detection efficiency (NPDE) factor for the two systems was determined from experiments with monodisperse aerosol. This factor is seen to be effective in characterizing and reconciling measurements made with these two SEMS instruments.     

Kinetics and neuro-fuzzy soft computing modelling of river turbid water coag-flocculation using mango (Mangifera indica) kernel coagulant

This study investigates kinetics and Adaptive Neuro-Fuzzy Modeling (ANFM) of river turbid water coagulation-flocculation (CF) process using mango kernel coagulant (MKC). CF experiments were performed using jar test apparatus and the process kinetic-transport parameters (coagulation rate constant, half-life time, and particle diffusivity) were determined using kinetic-transport models. Grid-partitioning neuro-fuzzy programming codes were written and implemented in Matlab 9.2 software environment for the development of neuro-fuzzy architecture. The ANFM input data include initial water pH, initial water turbidity, biocoagulant dosage, CF time, and turbidity removal percentage (TRP) as output data. Generalized bell membership function was optimally selected for fuzzification of input variables and a hybrid algorithm was considered for the learning method of input-output data with constant output membership type. The minimum turbidity (0.51 NTU) of treated water was achieved at pH 12 and coagulant dosage of 2.5?mg/L with coagulation rate constant, half-life (t_1/2) and particle diffusivity 0.0194?s^?1, 10.01?min, and 7.267?×?10^?14 m²/s, respectively. The correlation coefficient (R²) between the experimental and neuro-fuzzy predicted values was 0.9924 and the ratio (K) of training error to testing error was 0.68. Thus, this study shows that ANFM can be used as a reliable tool for modeling river water CF and kinetic-transport parameter results are useful in process design, optimization, and control.     

Effects of pressure and precursor loading in the flame synthesis of titania nanoparticles

The synthesis of TiO₂ nanoparticles is investigated experimentally and computationally in low-pressure H₂/O₂/N₂ burner-stabilized flat stagnation flames, using titanium tetra-iso-propoxide as precursor. The flow field is modeled with detailed chemical kinetics and transport, and is compared with measurements using laser-induced fluorescence to map gas-phase temperature and OH-radical species concentration. A sectional model, coupled with the simulated flow field and flame structure, is employed to model particle growth dynamics, computing aggregate particle size distribution, geometric standard deviation, and average primary particle size. The computations are compared with the experiments, for which in situ characterization of the nanoparticles in the flow field is accomplished by a low-pressure aerosol sampling system connected to a nano-scanning mobility particle sizer. Effects of operating pressure and precursor-loading rate on particle growth are examined experimentally and are compared with computational modeling. Different from other works, temperature profiles, rather than mass flow rate, are fixed using strategic dilution to base the comparisons. Higher pressures produce larger aggregate particles, but also smaller primary particles, due to longer residence times, as seen in both the experiments and computations. For higher precursor-loading rates, aggregate particle size is larger (for both experiments and computations), while primary particle size remains constant for the experiments and decreases slightly for the computations in the corresponding range.     

Estimation of permeation rate of chemicals through elastometric materials

Elastometric materials are used as barriers to protect workers against exposure to chemicals. The effectiveness of a polymer as a chemical protective material therefore depends on the rate of the permeation of chemicals through it. The permeation rate depends on the solubility and the diffusion coefficient of chemicals in the materials. The diffusion coefficient itself is a strong function of concentration of the chemicals in the polymeric material. Permeation rates can be measured directly using a permeation cell or they can be calculated from the solubility and the diffusion coefficient data. Sorption/desorption experiments can be used to determine solubility and an expression for the diffusion coefficient in terms of concentration. Experiments were conducted for the sorption and desorption of ethyl acetate in three glove (one butyl and two neoprene materials) and two garment (neoprene and chlorinated polyethylene) materials. The data collected were used to estimate the steady‐state permeation rates of ethyl acetate through the materials. The results of the experiments show that the solubility of ethyl acetate in butyl rubber is 0.795 g/cm³, and the steady‐state permeation rate is 0.32 μg cm⁻² s⁻¹. The solubility of the chemical through the three neoprene materials is in the range of 2.25–5.31 g/cm³, and the steady‐state permeation rates vary from 27 to 43 μg cm⁻² s⁻¹. The solubility of ethyl acetate in the chlorinated polyethylene is 7.14 g/cm³, and the steady‐state permeation rate is 62.43 μg cm⁻² s⁻¹. The experimental method is very simple to use and it requires a small sample of the material (less than 1 cm²) and only a few milliliters of the chemical. Sorption/desorption experiments can also provide information on the amount of additives extracted from an elastomeric material during contact with a chemical. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1265–1272, 2001     

Modelling Cd(II) removal from aqueous solutions by adsorption on a highly mineralized peat. Batch and fixed‐bed column experiments

This paper evaluates the potential use of a locally available organic soil amendment as a low‐cost adsorbent. The removal of cadmium from aqueous solutions was studied by means of kinetic, batch and fixed‐bed experiments. Batch experiments were conducted to evaluate the process kinetics and the removal equilibrium over a broad pH range. Pseudo‐second‐order kinetics and Freundlich equilibrium parameters were obtained. Six column experiments were carried out at different flow‐rates and feed concentrations. Breakthrough curves showed higher metal retention than expected from the batch adsorption isotherms. Column modelling assuming rate‐controlled pore diffusion was successfully performed. The adsorption process was reversed, regenerating the columns by eluting the cadmium using 0.1 mol dm^?3 hydrochloric acid. The high retention capacity together with the favourable structural characteristics indicated that this material could be used as an effective and low‐cost adsorbent for treatment of wastewaters containing heavy metals. Copyright © 2006 Society of Chemical Industry     

Effects of diffusion on the kinetic study of the system BADGE n = 0/m‐xylylenediamine

The curing reactions of an epoxy system composed of a diglycidyl ether of bisphenol A (BADGE n=0) and m‐xylylenediamine (m‐XDA) were studied. Two models, the first based solely on chemical kinetics and the second accounting for diffusion, were used and compared to the experimental data. The epoxy resin was used as received in a first series of experiments. In a second series of experiments, the resin was purified in vacuo (180°C and 1 mmHg). The inclusion of a diffusion factor in the second model allowed for the cure kinetics to be predicted over the whole range of conversion covering both pre‐ and postvitrification stages. The investigation was made in the temperature range 50–110°C, which is considered optimum for the isothermal curing of the epoxy system studied. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2997–3005, 1999     

Nitrite Removal Using Ion Exchange Resin: Batch vs. Fixed Bed Performance

Nitrite is an important pollutant appearing in the large amount of wastewater from flue gas denitrification process. Its removal is essential for wastewater discharge or reuse. In this paper, we made an attempt to remove nitrite using ion exchange resin (IXR) by conducting batch experiments first, in which adsorption equilibrium and kinetics were determined. Fixed bed experiments were then carried out to investigate bed breakthrough and elution behavior. Isotherm data showed that nitrite adsorption on IXR fitted Freundlich model better than Langmuir model. Kinetic data from batch experiments were well correlated with second-order reversible kinetics model. From bed experiments, it was found that increase in flow rate and inlet concentration decreased breakthrough time, but the capacity of saturated adsorption stayed almost the same. It was also found that the capacity of adsorption decreased in the presence of other anions. Breakthrough curves under various operating conditions were well predicted by the Thomas model, and nitrite ions adsorbed in the bed could be completely eluted by using 3.0 wt% NaCl solution at flow rate of 3.0 L?h^?1.