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Chemical Process Principles. Part One: View: PDF | PDF w/ Links Elementary Principles of Chemical Processes (Felder, Richard M.; Rousseau, Ronald W.). In the second part the fundamental principles of thermodynamics are pre- sented with rium compositions in both physical and chemical processes. Because of. Chemical process principles‐part 1, Material and Energy Balances. O. A. Hougen , K. M. Watson, and R. A. Ragatz. Second Edition. John Wiley & Sons, Inc.

Chemical Process Principles Pdf

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Chemical process principles‐part 1, Material and Energy Balances. O. A. Hougen , K. M. Watson, and R. A. Ragatz. Second Edition. John Wiley & Sons, Inc., New. Chemical Process pixia-club.info - Ebook download as PDF File .pdf), Text File . txt) or read book online. Solution Manual for Chemical Process Principles by Hougen and Watson Part 1 PDF - Download as PDF File .pdf), Text File .txt) or read online.

Professor of Chemical Engineering.. Gmehling, J. Download PDF K. Download Meta. It is widely known that the enthalpy-concentration diagram is useful for the calculation of heat balances in physical and chemical processes of binary systems.

Ragatz,"Chemical Process Principles",. In its 90 year life what has chemical engineering ChE contributed to society? Firstly, we have invented and developed processes to create new materials, more gently and more e ciently, so as to make life easier for all. Secondly, ChE has changed our accepted concepts and our ways of thinking in science and technology. Felder Richard M. Reklaitis G. Beveridge and R. Schechter, Optimization,. Gangaiah, Optimization. Techniques for Chemical Engineering, MacMillan,.

Delhi, Edgar, D. Fuels and combustion calculation, proximate and ultimate analysis, adiabatic reaction temperature, air to fuel ratio, complex processes calculation. Balance, John. Hall, 6th Ed. Chemical Process Principles; O. M Watson, R. Distributors, Formation, Solution by direct integration method, Linear equation of first order, Homogeneous linear equation with.

Balance 2nd. This is a recasting of the seminal MIT book Principles of. New York,. Hougen and Kenneth M. Watson, Show the sequential processes b and. At the critical temperature and pressure, the z.

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Historical Perspective: More than half a century ago, the typical chemical engineering program began with a course devoted to material and energy balances. Stoichiometry was covered in four pages and restricted to. Thermodynamics and. Phase Equilibria. Energy Technology. Advance Chemical. Reaction Engineering. Research topic specific. Written examination. This solution is analogous to the sine and cosine solutions if one replaces the negative sign with a positive.

Felder and Ronald W. Chemical Process Principles, O. The basic chemical principles of catalysis consist in. Extensive data on viscosities of pure gases and liquids are available in various science and engineering handbooks. M and Ragatz, R. Chemical Engineering B.

The total number of credits for the B. Program in Chemical. Engineering is Books Recommended: 1. Basic principles and calculation in chemical engineering —David mautner ,himmelblau, james B.

Introduction to unit operations and unit processes. Units and. Get access to the full version of this article. View access options below. You previously purchased this article through ReadCube.

Institutional Login. Log in to Wiley Online Library. Purchase Instant Access. View Preview. Learn more Check out. Volume 1 , Issue 1 March Pages Related Information. Email or Customer ID. Forgot your password? Forgot password? Kelvin Atmospheres Cubic centimeters Per pound-mole temperatures: The numerical value of R has been carefully determined and may be expressed in any desired energy units. It establishes the normal' molal volume constant required in the system of calculation described in the preceding section.

It also furnishes convenient specifications under which quantities of gases may be compared when expressed in terms of volumes. Standard Conditions. Under these conditions the normal molal volumes are as follows the abbreviation S.

II quirement being that the units in both initial and final states be the same. The normal molal volume at any one set of standard conditions. The general type of problem involving weights and volumes at any desired conditions may then be solved in two steps..

Equation 5 is in form to permit direct solution of problems of the second type. So many units of expression are in common use for each variable quantity that a very large table of values of R would be required or. It proves much more desirable to separate such calculations into two steps. Either method is inconvenient. Volume of 1 gram-mole S.

Some such specification is necessary because of the fact that the volume of a gas depends not only on the quantity but on the temperature and pressure as well.

In the other step the relationship'between volume at standard conditions and weight is determined by means of the normal molal volume constant. It is recommended that these conditions be adopted as the standard for all calculations.

The volume. With weights expressed in molal units the equation may be solved for any one of the four variables if the other three are known. The normal molal volume is the volume occupied by one mole of a gas at arbitrarily selected standard conditions. An arbitrarily specified standard state of temperature and pressure serves two purposes.

As a primary constant. In one. In order to calculate any one of these properties the others must be known or specified. Higher pressures cause condensation.

In such a case the volume at standard conditions indicates the hypothetical volume which would be occupied by the substance if it could exist in the vapor state at these conditions and if it obeyed the ideal gas law.

The conditions of the standard state may be expressed in any desired units as in the following tatfcle: All ordinary pressure gauges indicate the magnitude of pressure above or below that of the atmosphere. Four different types of problems arise. The average atmospheric pressure at sea level is On this basis air has a normal density of 1.

The following illustrations show the application of the recommended method of calculation to each of these types of problems. The ratio of pressures or temperatures should he greater than unity when the. For establishment of correct ratios to account for the effects of pressure and temperature a simple rule may be followed which offers less opportunity for error than attempting to recall Equation The gas law expresses the relationship between four properties of a gas: The density of a gas is ordinarily expressed as the weight in grams of one Hter or the weight in pounds of one cubic foot.

The specific gravity of a gas is usually defined as the ratio of its density to that of air at the same conditions of temperature and pressure.

In order to obtain the absolute pressure which must be used in the gas law. There are many substances which cannot actually exist in the gaseous state at these specified conditions. Gauge Pressure.

From Equation Volume at S. It is desired to compress 10 lb of carbon dioxide to a volume of 20 cu ft. Pi Vi Temperature at 30 cu ft. Calculate the weight of cu ft of water vapor.

Assuming the appUcability of the ideal gas law. Illustration 1 Volume Unknoivn. The ratios should be less than unity when the changes are such as to cause decrease in volume. II changes in pressure or temperature are such as to cause increase in volume. Ammonium chloride molecules in the vapor state separate into molecules of hydrogen chloride and ammonia: Ammonium chloride. Illustration 5. By decomposition. Assuming that the ideal gas law applies. The total pressure is equal to the sum of the pressures exerted by'the molecules of each.

For this reason.

Elementary Principles of Chemical Processes

Certain chemical compounds when in the gaseous state apparently do not even approximately follow the relationships deduced above. The tendency of hydrogen fluoride to associate into large molecules was mentioned in Chapter I.

The partial pressure as defined above does not represent the actual pressure exerted by the molecules of the component gas when present in the mixture except under certain Knuting conditions. From the simple kinetic theory of the constitution of gases it would be expected that many properties of gaseous mixtures would be additive.

The additive nature of partial pressures is expressed by Dalian's law. Before considering the actual behavior of gaseous m. By definition. Laws of Dalton and Amagat. In a mixture of ideal gases the molecules of each component gas behave independently as though they alone were present in the container..

These statements apply to all gases. The pure-component volume generally has been termed partial volume in the past. Pure-component volumes and partial volumes are not necessarily the same except under ideal conditions. Where conditions are such that the ideal gas law is applicable: The presence of new molecules will reduce the space available for the free motion of those originally present and will exert attractive forces on them.

Where small molal volumes are encountered. Combining these equations with Dalton's law.

These same effects are present but negligible under conditions of large molal volumes and wide separation of molecules. Equation As a result. Equation 17 then signifies that. Under such conditions pressures may not be additive. By combining Equations 15 and 16 a useful relationship between total and partial pressure is obtained. Adding these equations. The weight of this molal quantity is then calculated and will represent the average molecular v.

A certain group of components of a mixture of gases may in many cases pass through a process without being changed in composition or weight.

Illustration 6. Average Molecular Weight of a Gaseous Mixture. It is frequently convenient to treat such a mixture as though it were a single gas and assign to it an average molecular weight which may be used for calculation of its weight and volume relationships. From Equations 16 and 20 it is evident thtit when the ideal gas law is valid both Amagat's and Dalton's laws apply.

By this method the average molecular weight of air is found to be Such an fiverage molecular weight has no physical significance from the standpoint of the molecular theory and is of no value if any component of the mixture takes part in a reaction or is altered in relative quantity. The average molecular weight is calculated by adopting a unit molal quantity of the mixture as the basis of calculation.

Calculate the average molecular weight of a flue gas having the following composition by volume: If the composition of a gas mixture is expressed in molal or weight units the density is readily determined by selecting a unit molal quantity or weight as the basis and calculating its volume at the specified conditions of temperature and pressure. Illustration 8. Density at 29 in. The volume at the specified conditions is then calculated from the ideal gas law.

Where the ideal gas law is applicable. The weight of the basic quantity is first calculated and then its volume at the specified conditions. In this case the volume analysis is the same as the molal analysis. Air is assumed to contain This method may be applied to mixtures which do or do not follow the ideal gas law. Calculate the density in pounds per cubic foot at 29 in.

Nitrogen The situation is ordinarily complicated by changes of temperature and pressure concurrent with the composition changes. It is of interest to calculate the relationships existing between the initial and final volumes of the mixture and the volume of the material removed or added to the mixture in such a process..

The relationships between molal units and volumes under any conditions are expressed by Equations 16 to Solution may be carried out by the methods of Chapter I if the quantities specified in the problem are first converted to weight or molal units. Illustration 9.

The following illustration demonstrates the method for a case in which the ideal. The average molecular weight of this mixture is As in the problems of Chapter I. The quantities which are unknown may then be calculated in these same units. The mixture of nitrogen and inert gases in the atmosphere may be termed atmospheric nitrogen. In a drying operation a stream of air takes on water vapor.

In the scrubbing of coal gas. The last step will then be the conversion of the results from molal or weight units into volumes at the specified conditions of temperature and pressure.

This method of solution may be applied with the use of either the ideal gas law or more accurate equations. Nitrogen Oxygen Carbon dioxide Water -. Volume of gas leaving. T h e total volume of any ideal mixture m a y be obtained by adding together t h e pure-component volumes of its components.

I n this case the solution m a y be carried o u t without conversion to molal or weight units b y appHcation of pure-component volumes.: C a r e m u s t be t a k e n in t h e use of this method t h a t all volumes which are added together are expressed at the same conditions of temperature and pressure.

This procedure is indicated in t h e following illustration: II Weight of water evaporated per cu ft of gas entering. Again t h e entire calculation m u s t be based on a definite q u a n t i t y of a component which passes through t h e process without change in q u a n t i t y. Where the ideal gas law m a y be applied. A process involving changes in t e m p e r a t u r e a n d pressure as well as composition is best considered as t a k i n g place in two steps: Pure-component vol..

The use of this method is shown in the following illustration: Illustration The volume of the mixture may then always be determined by application of the gas law to any components which pass through the process unchanged in quantity and whose partial pressures are known at both the initial and final conditions. The actual volumes of chlorine entering and leaving are also and The partial pressure of the chlorine is 59 mm of Hg.

The actual volume occupied by each of these components will always be exactly the same as that of the entire mixture. This The addition or removal of a component of a mixture may be considered as producing only a change in the partial pressure of all of the other components.. In certain types of work. Where data are presented in this form. In Chapter I methods are demonstrated for the solution of reaction calculations through the use of molal units for the expression of quantities of reactants and products.

In general. All quantities of active materials. Quantities of gases are ordinarily expressed in volume units because of the fact that the common methods of measurement give results directly on this basis.

By the use of the normal molal volume constants combined with the proportions of the ideal gas law it is easy to convert from molal to volume units. Where this is the scheme of calculation.. If the data are in volume units. The methods of conversion have been explained in the preceding sections. Nitric acid is produced in the Ostwald process by the oxidation of ammonia with air. The following reaction takes place: The general types of reaction calculations must.

The most convenient choice of a quantity of material to serve as the basis of calculation is determined by the manner of presentation of the data. Results are thus obtained in molal units which may readily be converted to volumes at any desired conditions. The same general methods of solution are followed" as were described in Chapter I. II Gases leaving catalyzer. The actual behavior of gases under high-pressure conditions is dis-. The ideal gas law is applicable only at conditions of low pressure and high temperature corresponding to large molal volumes.

At conditions resulting in small molal volumes the simple kinetic theory breaks down and volumes calculated from the ideal law tend to be too large. If an error of 1 per cent is permissible the ideal gas law may be used for diatomic gases where gram-molal volumes are as low as 5 liters 80 cubic feet per pound-mole and for gases of more complex molecular structure such as carbon dioxide.

In extreme cases the calculated volume may be five times too great. NII3 oxidized in catalyzer. An automobile tire is inflated to a gauge pressure of 35 lb per sq in. Calculate the maximum temperature to which the tire may be heated without the gauge pressure exceeding 50 lb per sq in.

C a 0 H 2 ' Calculate the number of hours of service which can be derived from 1. I t may be assumed t h a t the ideal gas law is applicable.

The gas acetylene is produced according to the following reaction by treating calcium carbide with water: A chimney gas has the following composition by volume: Calculate the densities in pounds per cubic foot at standard conditions and the specific gravities of the following gases: Calculate the number of cubic feet of hydrogen sulfide.

I t is desired to market oxygen in small cylinders having volumes of 0. A natural gas has the following composition by volume: A gas mixture contains 0. Assume t h a t the volume of the tire does not change. Calculate the volume occupied by this mixture and its density in pounds per cubic foot at a pressure of 40 lb per sq in.

The total pressure of the wet air may be taken as constant at t h e barometric value of mm. A producer gas has the following composition by volume: CO The gases leave the tower at a pressure of mm of Hg.

Air is passed into a dryer for the drying of textiles a t a rate of cu ft per min. Using the ideal gas law. U Using the ideal gas law. By electrolyzing a mixed brine a mixture of gases is obtained a t t h e cathode having the following composition by weight: CU Brj O2: Using the partial pressure method.

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The gas is passed at a rate of cu ft per min through an absorption tower in which only ammonia is removed. Without changing the total pressure. After cooling it is found t h a t t h e partial pressure of t h e water vapor is SO2 O2 Ni. The gas from a sulfur burner has the following composition by volume: Carbon Ash The The composition by volume of the stack gases from the furnace is as follows: Coke containing A furnace is to be designed to burn coke at the rate of lb per hour.

Of the NO2 formed.

In the fixation of nitrogen by the arc process. Some of the nitrogen is oxidized to NO. The gases are then passed into water-washed absorption towers where nitric acid is formed by the following reaction: H2O -I. II Molecules in the gaseous state of aggregation exhibit two opposing tendencies. The translational kinetic energy possessed by each molecule represents a continual. The second tendency. The greatest attractive force between the two molecules exists when they are sepa.

If the distance of separation is diminished below Sj. This behavior is shown in Fig. If unaffected by other forces. The first tendency. When a gas is isothermally compressed and the distances of separation between the molecules are decreased.

An increase in the temperature will increase the translational kinetic energy of each molecule and will therefore give it an increased ability to overcome the forces tending to draw it toward other molecules. In order to separate them by a distance greater than S2 it would be necessary to overcome the maximum attractive force by heating or expansion. Attractive force between molecules.

These intermolecular attractive forces are believed to be of such a nature that they increase to definite maxima as the distances between molecules are diminished. At a distance of separation Si the attractive force becomes zero. This has given rise to the concept of reduced temperature.

If these attractive forces become so large that the potential energy of the attraction of one molecule for another is greater than its kinetic energy of translation.

The temperature at which the molecular kinetic energy of translation equals the maximum potential energy of attraction is termed the critical tem. The pressure required to liquefy a gas at its critical temperature is termed the critical 'pressure.

Reduced Conditions. Below the critical temperature a gas may be liquefied if sufficiently compressed.

Elementary Principles of Chemical Processes, 3rd Update Edition

Critical Properties. If the temperature is sufficiently high that the kinetic energies of translation of the molecules exceed the maximum potential energy of attraction between them.

In Table XI. The characteristic which differentiates a liquid from a gas is the fact that the liquid possesses a definite volume and does not necessarily occupy the entire available space. The volume at the critical state is termed the critical volume.

At conditions equally removed from the critical state many properties of different substances are similarly related. The density at the critical state is the critical density. The individual molecules of the liquid are in motion. The critical pressure and temperature fix the critical state at which there is no distinction between the gaseous and liquid states. Above the critical temperature the liquid state is impossible for a single component and compression results only in a highly compressed gas.

Whether or not a substance can exist in the hquid state is dependent on its temperature. It will be recalled that the pressure exerted by a gas or vapor is due to the impacts of its component molecules against the confining surfaces.

In every liquid and gas there are always highly energized molecules moving at speeds much higher than the average. Since the. When such a molecule comes to the surface of a liquid.

Actually it has been demonstrated that this is not the case and that molecular speeds and energies vary over wide ranges above and below the average values. These conditions are brought about when the temperature of a substance is lowered. When a liquid evaporates into a space of limited dimensions the space will become filled with the vapor which is formed.

One of the surface molecules may be removed only by overcoming the attractive forces holding it to the others. Once it has passed this distance of maximum attraction.

This phenomenon of the breaking away of highly energized molecules takes place from every exposed liquid surface. It will be later shown that many properties of gases and liquids. This is possible if the molecule is given sufficient translational kinetic energy to overcome the maximum potential energy of attraction and to enable it to move past the point of maximum attraction. On the basis of this theory the surface of a liquid may be pictured as a layer of molecules.

As pointed out above. This phenomenon is termed vaporization or euaporation. As vaporization proceeds. In the simple kinetic-theory mechanisms which have been discussed. The magnitude of the equilibrium vapor pressure is in no way dependent on the amounts of liquid and vapor as long as any free liquid surface is present.

All materials exhibit definite vapor pressures of greater or less degree at all temperatures. The nature of the liquid is the most important factor determining the magnitude of the equilibrium vapor pressure. I l l original liquid surface forms one of the walls confijiing the vapor.

It follows that when a liquid evaporates into a limited space. The process of condensation tends to change the gas which is formed by vaporization back into the liquid state. If sufficient liquid is present. If the pressure of the vapor is changed in either direction from this equilibrium value it will adjust itself and return to the equilibrium conditions owing to the increase or decrease in the rate of condensation which results from the pressure change.

Since all molecules are endowed with the same kinetic energies of translation at any specified temperature. When this condition is reached. This phenomenon. The rate of condensation is determined by the number of molecules striking the liquid surface per unit time. The pressure exerted by the vapor at such equilibrium conditions is termed the vapor pressure of the liquid. This results from both the rate of loss and the rate of gain of molecules by the liquid being directly proportional to the area exposed to the vapor.

At the equilibrium conditions when both rates are the same. These potential energies are determined by the intermolecular attractive forces. The rate of condensation is increased as vaporization proceeds and the pressure of the vapor increases. The process of vaporization tends to change the liquid to the gaseous state.

The number of such impacts will be dependent on or will determine the pressure exerted by the vapor. If a saturated vapor is cooled or compressed. This vaporization will cause the formation of bubbles of vapor which crowd back the surrounding liquid and increase in size because of the greater pressure of the vapor.

Superheat and Quality. Boiling results from the formation of tiny free spaces within the liquid itself. Boiling Point. A vapor which exists above its critical temperature is termed a gas.

When a liquid surface is exposed to a space in which the total gas pressure is less than the equihbrium vapor pressure of the liquid. A vapor whose partial pressure is less than its equilibrium vapor pressure is termed a superheated vapor.

The magnitudes of the attractive forces are dependent on both the size and nature of the molecules. If the vapor is in turbulent motion considerable portions of the condensed liquid will remain in mechanical suspension as small drops in the vapor and be carried with it. A vapor which exists under such conditions that its partial pressure is equal to its equilibrium vapor pressure is termed a saturated vapor.

The distinction between a vapor and a gas is thus quite arbitrary. The quality of a wet vapor is the percentage which the weight of vapor forms of the total weight of vapor and entrained liquid associated with it. The temperature at which a vappr is saturated is termed the dew point or saturation temperature.

If the equilibrium vapor pressure is greater than the total pressure on the surface of the liquid. Such a bubble of vapor will rise to the surface of the Uquid and join the main body of gas above it. The difference between its existing temperature and its saturation temperature is called its degrees of superheat. When the total pressure is such that boiling does not take place. These factors all contribute to make vaporization of a liquid relatively very rapid when boiling takes place.

Sublimation will take place whenever the partial pressure of the vapor in contact with a solid surface is less than the equifibrium vapor pressure of the solid. SoUd substances possess a tendency to disperse directly into the vapor state and to exert a vapor pressure just as do liquids. The vapor pressures of solids.

A solid exerts an equilibrium vapor pressure just as a liquid does. The boiling point is dependent on the total pressure. This is the temperature at which the equilibrium vapor pressure equals millimeters of mercury or 1. At temperatm'es above the melting gpint the solid state cannot exist. A f amifiar example of sublimation is the disappearance of snow in sub-zero weather.

The vapor pressures of supercooled liquids are always greater than those of the solid state at the same temperature. At the melting point the vapor pressures of a substance in the solid and liquid states are equal. The vapor once liberated from the liquid is at a higher pressure than the gas in which it finds itself and will immediately expand and flow away from the surface. Vapor Pressures of Solids.

The temperature at which a liquid boils when under a total pressure of 1. The transition of a solid directly into the gaseous state is termed sublimation. The temperature at which the equilibrium vapor pressure of a liquid equals the total pressure on the surface is known as the boiling point. The rising bubbles also break up the normal surface into more or less of a froth.

I l l contact between the liquid and bubbles of vapor. The principles and methods outlined in the following sections are equally applicable to sublimation and to vaporization processes. It follows that an increase in kinetic energy of molecular translation should increase the rate of vaporization and therefore the vapor pressure.

An exact thermodynamic relationship between vapor pressure and temperature is developed in Chapter XI as T V. On the basis of this theory. In Chapter II it was pointed out that the kinetic energy of translation is directly proportional to the absolute temperature. This is found to be universally the case where vapor pressures have been experimentally investigated.

Calculations dealing with the vapor pressures and sublimation of solids are analogous to those of the vaporization of Uquids. It is therefore impossible for liquid carbon dioxide to exist in a stable form at pressures less than 5. It is entirely rigorous. It must be remembered that it is the temperature of the liquid surface which is effective in determining the rate of vaporization and the vapor pressure.

Its use in this form is. The latent heat of vaporization. Molecular weight X R To Po.

Ill vapor state at the same temperature. The results are accurate only over limited ranges of temperature in which it may be assumed that the latent heat of vaporization is constant and at such conditions that the ideal gas law is obeyed.

The heat of vaporization decreases as pressure increases. Illustration 1. By neglecting the volume of liquid and assuming the applicability of the ideal gas law the above relation reduces to the Clausius-Clapeyron equation: The latent heat of vaporization is This property is fully discussed in subsequent chapters.

Where the temperature does not vary over wide Hmits it may be assumed that the molal latent heat of vaporization. X is constant and Equation 2 may be integrated. Use of an ordinary uniform scale of coordinates does not result in a satisfactory plot because of the wide ranges to be covered and the curvature encountered. In the preceding illustration the Clausius-Clapeyron equation yields results which are satisfactory for many purposes. These scales do not reduce the curvature of the vapor-pressure lines as much as the use of the reciprocal temperature scale but are more easy to construct and read.

Because of the frequent requirement of accurate values of the vapor pressure of water. It should be used only in the absence of experimental data. Another method is to plot the logarithm of the pressure against temperature on a uniform scale. The resulting curves. Tables of physical data contain experimentally determined values of the vapor pressures of many substances at various temperatures.

A single chart cannot be used over a wide temperature range without sacrifice of accuracy at the lower temperatures and the rapidly changing slope makes both interpolation and extrapolation uncertain.

Equation 3 is only an approximation which may lead to considerable error in some cases. Where only limited data are available there is great advantage to a method of plotting which wifl yield straight lines over a wide range of conditions. A function of the temperature at which some other substance exhibits a given vapor pressure may then be plotted against the same function of the temperature at which the reference substance has the same vapor pressure. The methods of plotting described above all result in lines having some degree of curvature.

Where an accurate evaluation of a physical property has been developed over a wide range of conditions for one substance the resulting relationship frequently may be made the basis of empirical plots for other substances of not greatly different properties.Chemical 1.

For such calculations it is not required to know the weight of the gas. Enter your email address below and we will send you your username. Following are other vapor pressure data: A pressure gauge reads 5. Shasha AR.

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