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Find the final temperature T2 and the change of internal en- ergy AUi2. Heat is slowly applied to the gas on the left side of the piston, which raises the gas pressure until the piston has compressed the gas on the right side to a pressure of 3. Find the T2 and V2 of the gas on the right side, noting that the process is adiabatic; then calculate the final temperature T2 for the gas on the left side; note this is a diabatic process.

Hint: Use the result of Problem 2. Find: a the pressures, volumes and temperature of the end states; b the change of internal energy for each process; c the change of specific enthalpy for each process. The low- est pressure and temperature, p3 and T3, are 14 psia and degR, respectively.

Find the mass M of the system and the highest pres- sure and temperature in the cycle. Air as a perfect gas comprises the system. The cyl- inder diameter bore is 3. The length traversed by the piston in moving between end states 1 and 2 the stroke is 4 inches. The maximum pressure occurs after the combustion or heating process, i.

Find the temperature, volume and pressure at each of the four states and the mass of the air comprising the system. Assume that the correct mixture comprises 0. For the mixture at 1 bar and degK and occupying a volume of 1 m3, find: a R; b m; cv; and cp. Find the number of moles of air that must be used to produce one mole of oxygen.

If a gas is compressed isothermally, it will become denser and will behave differently from an ideal gas. It becomes a real gas or va- por under these conditions. In the ideal gas the molecules are so far apart that they do not interact. With the real gas or vapor the molecules are closer and do, in fact, attract or repel one another.

If the compression is continued, the point at which condensa- tion begins is reached. Figure 3. The locus of these points on the p-v diagram is a curve labeled "saturation. The highest pressure on the va- por dome, which is the point of zero slope, is called the critical pressure, and the point of highest pressure is called the critical point.

The vapor dome to the left of the critical point has a large positive slope and is called the saturated-liquid line. Examination of Figure 3. The first region is one of high specific volume v, in which the molecules are widely separated, and the gas is gov- erned by the perfect-gas equation of state.

The second region is located nearer to the saturated-vapor curve and is a region of dense gas, called the superheated-vapor zone. The third region is the one bounded on the right by the saturated-vapor curve and on the left by the sataurated-liquid curve. This is the mixture zone, and there is a mixture of saturated vapor and saturated liquid in this zone.

A horizontal line drawn on Figure 3. If the state corresponds to the left end of such a line, the system is one of percent saturated liquid. If the state is indicated by the point at the right end of the line, then percent saturated vapor is indicated.

A point at the middle of the horizontal line indicates a state in which half of the substance is saturated liquid and half is saturated vapor. Using the concepts presented in Chapter 2, the equation of state is geometrically represented by a surface inp-v-T space. Such a rep- resentation is made in Figure 3.

We note in this figure that the equation of state is represented by several intersecting surfaces. The surface labeled liq-vap in Figure 3. The iso- therms form the surface in the gaseous region to the right of the. The isotherm passing over the top of the vapor dome is the critical isotherm. The isotherm which passes through the vapor dome represents any isotherm. It has branches on three of the surfaces. The right branch is on the superheated vapor surface; the middle branch is in the liquid-vapor mixture zone; and the left branch is on the liquid surface.

All three branches of this curve have the same temperature; pressure varies along the left and right branches, but pressure remains constant on the middle branch. Other properties are also different at each point on the iso- therm. It is necessary to use tabulated properties to determine the values of properties in each of the three zones traversed by the isotherm. We will use the steam tables, found in Appendices Al and A2, to illustrate how properties of real substances can be de- termined.

Such a procedure is equivalent to the use of an equation of state, if one were one available. Ideal Processes of Real Substances If the surface representing the liquid-vapor mixture zone in Figure 3.

This curve is a plot of boiling point temperatures against liquid pres-. For precise values of boiling point temperature we must re- fer to a table like that in Appendix Al. This table contains the properties of saturated steam H2O as a function of saturation pressure; thus, the boiling point temperatures, or saturation tem- peratures, for water can be obtained from this table.

A plot of satura- tion pressure as a function of saturation temperature for H2O, having the same form as curve in Figure 3. The diagram formed by this plot on the p-T plane is called a phase diagram. The curve delineates the the states where phase change occurs; thus, the area to the left of the curve represent purely liq- uid states, whereas that to the right of represents the domain of gaseous states. A point on the phase-change curve actual repre- sents a line when projected to the p-v plane, e.

The steam table enables the determination of other properties inside the liquid-vapor mixture zone. Referring to Figure 3.

Specific entropy is a property which will be introduced in Chapter 6. Entropy is denoted by S and specific entropy by s; specific entropy has units of energy by units of mass per degree, e. Density p is the reciprocal of specific volume v, and enthalpy h was introduced previously. Consider one kilogram of water at a pressure of one bar 0.

One should note that the pressure and temperature have not changed during vaporization, but the volume and enthalpy have risen sig- nificantly. The mass fraction of a mixture that is saturated vapor is de- noted by jc, which is known as the quality of the mixture. Similarly, the mass fraction of saturated va- por x times the specific enthalpy of the saturated vapor hg yields the contribution to the mixture enthalpy from the vapor present. The units of the mixture enthalpy hmix, or simply h, are then en- ergy per unit mass of mixture; thus, the mixture enthalpy in the above example, viz.

A parallel process is used to calculate other properties of a mixture of saturated liquid and saturated vapor. For example, specific volume v of the mixture is calculated by. Other properties, such as density p, specific entropy s, or specific internal energy u, are handled in the same manner.

Properties in the superheated vapor region, i. In this table values of v, h and s are given for specified pressure and temperature, i. Although any of the three properties in 3. Specific volume v or entropy s would be determined from the table in the same manner. The surface to the left of the vapor dome in Figure 3.

As with the superheated vapor tables, two properties, usually pressure and temperature, are used to enter a table of experimentally based properties.

Appendix A3 contains tables of this sort for compressed water. The table contains the properties of compressed, or subcooled, water for temperatures below the boiling temperature.

For example, con- sider the table for the pressure 60 bars. The saturation temperature for this pressure is If the steam has a temperature above If the temperature is below Tables of this kind are consulted when the pressure for the state considered is higher than the saturation pressure for a given tem- perature; thus, they are tables of properties for compressed liquids.

The differences in enthalpy of a liquid at saturation pressure and at an elevated pressure is not large. Consider the data presented in Table 3. The pressure is increased to bars. Table 3. We note that the specific enthalpy rises by five percent with this very large pressure rise; while the specific volume decreases by 0.

The volume change is often neglected in such problems, and the enthalpy change is estimated by the equation,. Applying 3. Refrigerant tables such as those appearing in Appendices Bl, B2, and B3 are constructed in the same way as the steam tables pre- sented in Appendices Al and A2.

The three refrigerants selected for use in this text are R, Ra, and R, and all tables are similar in arrangement to those in Appendix A, except that the units for R and Ra are slightly different, viz.

English units are used for the refrigerant R Generally, the tables are arranged and used in the same manner as the steam tables. It is noted that no tables of compressed liquid are provided. Equation 3. The four principal components of a steam power plant cycle were discussed in Chapter 1. The schematic representation is repeated in Figure 3.

Four key states are identified, viz. State 1 is that of the steam leaving the steam generator and en- tering the turbine or other prime mover. The steam is expanded quickly in the turbine, so that the process may be considered to be adiabatic, i. Actually heat loss does occur in the connecting piping and through the casing walls of the ma- chine itself.

Further, fluid friction acts on the steam as it passes between the turbine blades. The ideal process for this expansion is both adiabatic and frictionless, and it is governed by equation 2. It will be shown in Chapter 6 that one property is held constant in such an ideal process, viz.

Recalling that fixing two properties also fixes the state and the other properties, then fixing s2 andp2 will suffice to fix the state of the exhaust steam. State 2 is typically located under the vapor dome, as shown in Figure 3. This is the mixture zone and the properties depend on the proportion of vapor and liquid; thus, equation 3. The ideal cycle for the components shown in Figure 3. The process is one of condensation, and the.

Rankine cycle process is ideal in the sense that no pressure change occurs, i. The pumping process changes the state from a saturated liquid to a compressed liquid. The change of enthalpy in this process is very small and can be estimated by 3. The steam generating unit or boiler is used to add heat to the compressed liquid, thus generating saturated or superheated steam.

The state changes from 4 to 1 in the boiler as is indicated in Figure 3. State 1 is represented by a point on the saturated vapor line in Figure 3. In either case the line joining 1 and 4 will be a horizontal, constant pressure line. The four processes of the Rankine cycle are the following: isentropic expansion isobaric cooling isentropic compression isobaric heating.

A typical refrigeration cycle comprises four components: a com- pressor, a condenser, a valve and an expander, as is illustrated in Figure 3. A refrigerant, such as Ra see Appendix B , enters the compressor as a vapor and is compressed. It is assumed that the compression is adiabatic and frictionless, i. In Figure 3. The pressure-enthalpy plane is used in Figure 3. Process in thep-h plane represents the isentropic compression.

In this process the pressure, temperature and en- thalpy increase together. Process is an isobaric cooling proc- ess. Process is the expansion occur- ing in the valve and is called a throttling process. This effect will be analyzed more carefully in Chapter 6.

The final process , which closes the cycle, is one of great importance, because it is the refrigeration process, i. The temperature of the refrigerant at state 4 is much lower than that of the surroundings, so that heat is easily transferred to it from the warmer surroundings. The ideal process is isobaric and iso- thermal, since the process is one of vaporization of the liquid in the mixture at state 4. State 1 is that of a saturated vapor; point 1 is on the saturated vapor line in Figure 3.

The refrigerant could exit the evaporated in a slightly superheated state, in which case the state point would be displaced to the right of its location in Figure 3.

The temperature for superheated vapor would be elevated above the saturation temperature corresponding to the evaporator pressure.

The point of tangency of the critical isotherm is the critical point, and the properties at this point are the critical properties. Of particular interest are the criti- cal pressure pc and the critical temperature Tc.

Each chemical substance has its unique values of critical pressure and tempera- ture. Some examples are given in Table 3. The critical values of pressure and temperature must be known to establish the equation of state for real gases. The equation of state is. The reduced pressure and temperature are defined as. Generalized compressibility charts, which allow the graphical de- termination of Z from a knowledge of reduced pressure and tem- perature, can be constructed.

According to Faires and Simmang , such charts are based on data for many different gases; thus, they apply to any gas. An example of tabulated values of compressi- bility factor is shown in Appendix C. The values of Z tabulated in the appendix are for nitrogen, but they are typicasl for other gases as well.

In general, Z deviates significantly from unity when gases exist at very high pressure or very low temperatures. Enthalpy change can be considered by means of the methods of section 1. We start with the equation of state in the form. Applying equation 2. Rather than substituting an algebraic function of T into 3. An example of a table of enthalpies of air at low pressures is presented in Appendix D. Tables such as the one in Appendix D can be found in the literature, e.

At extremely high pressure it is necessary to account for com- pressibility in the determination of enthalpy. An example of a table of enthalpies for gas at high pressures is presented in Appendix E.

Real gas ef- fects can cause the compressibility factor to deviate significantly from unity. Moran, MJ. Fundamentals of Engineer- ing Thermodynamics. The turbine inlet state is state 1.

De- termine the specific enthapy and specific volume of the entering steam. Find the specific enthalpy and specific volume of the compressed liquid leaving the pump state 4 in Figure 3.

If the heat removed from the steam during condensation is given by h2 - h3, determine the heat removal in the condenser per kilogram of con- densate. The system exe- cutes four processes: is a constant pressure heating at 10 bars pressure; is a constant volume cooling which reduces the pres- sure to 1 bar; is constant pressure cooling; and closes the cycle with a constant volume heating process which ends at state 1 with a saturated liquid at 10 bars pressure.

State 2 is a saturated vapor at 10 bars; thus, process is a process involving total va- porization of the original liquid. Process is a condensation process which begins with a high quality wet steam and ends with a low quality mixture. Use the steam tables to determine quality, specific volume, specific enthalpy and specific internal energy at all four states.

The system executes four processes: is a constant temperature heating in which saturated liquid at 10 bars is boiled until the quality is 1.

Hint: Use the ratio of finite differences, viz. Determine the differences in the above equation at 1 bar using temperatures on each side of the desired temperature. Use the air tables to determine the initial specific enthalpy, the final specific enthalpy, the average specific heat of the air in the above range of temperatures and the change of internal energy.

Using the steam tables determine the initial and final enthalpies of the steam. Find the quality of the exiting steam. Use the perfect gas equation of state to find Vl and T3. Use the air tables to determine specific enthalpies at states 1, 2 and 3. The gas constant for air is Use the tables to determine the value of the compressibility factor Z for the compressed gas. Determine the specific volume of the stored nitrogen and the mass of gas in the tank.

Find the compressibility factors, Zj and Z2, at the end states, i. Also determine the specific enthalpies, hi and h2, cor- rected for real gas effects. The liquid enters the expansion valve and exits with an unchanged enthalpy, i.

Work Intuitively we conceive of a force as a push or pull; additionally, one must conceive of an object upon which the force acts. Since the object has finite dimensions and size, it must possess properties of both volume and mass. The most commonly observed force is that of gravity, which is the pull of the earth on every object on or near the earth's surface. The magnitude F of the gravitational force is quantified by means of Newton's law of gravitation, viz.

It is seen from 4. Comparing 4. GmE "- 4. When numerical values are substituted in 4. When 4. Since work is done by the gravitational force as a body moves downward in free fall, a body falling from rest will acquire a kinetic energy exactly equal to the work done on it. Using the principle that work is force times displacement, we can write. The work done by an external force in elevating the body from z2 to Zi can be calculated using 4.

The work of lifting the body has the same magnitude but the opposite sign. If the body is taken as the thermodynamic system, the work done by the external agency in lifting it is also the thermodynamic work. It is the thermodynamic work because the stored energy of the system has been changed, viz. If F is replaced with ma from 4. Integration of 4.

Equation 4. Eliminating W between 4. One can view 4. What then is the role of work in the exchange of energy accompanying the object's fall? Equations 4. As mentioned above, thermodynamic work is work that changes the energy stored in a system. If the free-falling body is taken as a thermodynamic system, the body does not undergo a change of stored energy, since there is no change in its internal energy, i. The resulting thermodynamic work is zero.

Clearly, the inertia force ma is equal and opposite to the gravitational force mg; thus, the net force and the net thermodynamic work are zero. Work resulting from the action of fluid pressure on a moving boundary, which can be a fluid or solid surface, is a major means of transferring energy to or from a thermodynamic system. The magnitude of the differential pressure force acting on a moving surface ispdA, where p denotes the pressure of the fluid in contact with the surface, and dA is the differential surface area.

Substitution of 4. The differential volume dV is the volume change of the system in contact with the moving surface. V Figure 4. An example of a moving boundary is the face of a piston which is moving in a cylindrical chamber in which a gas is confined. Here the confined gas is the system.

The process of the expansion of a gas in a piston-cylinder device is shown with pressure-volume coordinates in Figure 4. The area under the process curve from point 1 to point 2 is a graphical representation of the work associated with the process , since it represents the value of the integral in 4. It should be noted that the work expressed by 4. Positive -work is done by the system on its surroundings, whereas negative work is work done by the surroundings on the system. As was mentioned in Chapter 1, both work and heat ate path functions, i.

As indicated in Table 2. Clearly an infinite number of paths between any two end states are possible. The polytropic process is a convenient way to represent a very large number of practical processes, but other representations are surely possible, e.

The main point to understand from the above discussion is that work is a path function. The processes discussed in Chapter 2 involve changes of state of a system of fixed mass undergoing energy exchanges with its surroundings through work or heat interactions.

This is often called a closed or non-flow system, since no mass flows across the system boundaries. Should fluid pass across system boundaries, e. The air compressor of Example Problem 2. During the outflow process the piston does work on the air, and the inflowing air does work on the piston.

There is no change of state during these processes, but work is done; this is so-called flow work, and it is different from moving boundary work discussed in the previous section for a non-flow system. In Example Problem 2. Like the compression process this sweeping process is negative work, but it is different because the properties of the air do not change during the sweeping process. Since the pressure is constant, the work done by the piston in process isp2 V2- F3. In flows through a pipe there occurs flow work across any arbitrarily chosen cross section.

Choosing a parcel of flowing fluid, say a cylindrical volume of diameter D and length L which occupies the section of the pipe just upstream of a given section. Fluid upstream of the parcel acts like the piston in Example Problem 2. Flow work per unit mass is then pressure times specific volume, pv. For analysis of these devices the control-volume method will be introduced in Chapter 5 and utilized in subsequent chapters.

The control-volume method it utilized to account for the flow of some property across its boundaries. Applied to thermodynamics the method accounts for energy flow across the boundaries of the control volume. Flow work is treated as an energy flow associated with the fluid flow, as indeed it has been shown to be.

Specific enthalpy h, defined by 2. Even though flow work is, in fact, work and not conceptually a property, it is the product of two properties and can be lumped together with specific internal energy to form the highly useful property enthalpy, which measures two forms of energy occurring in flowing systems.

Thus, flow work usually appears in flow equations as part of the property enthalpy and is thereby separated from moving boundary work. The concept of a thermodynamic cycle was introduced in Chapters 1 and 2. The concept of work as an area under a process was introduced in the present chapter. Since a cycle comprises a set of processes, the work of a cycle is logically the sum of the works of the individual processes in the cycle. Recall that the work is positive when the state point moves from left to right on the p-V plane, and it is negative when the state point moves from right to left.

Clearly for the cyclic process to close at the starting point, there must be movement of the state point in both directions to effect a closure. Chapter 4. In Figure 4. The area under process a-b represents the positive work of this process. On the other hand, process b-a moves the state point along the lower path, and the area under the curve b-a represents negative work.

The two processes together constitute a cycle, and the enclosed area of the figure represent the net work of the cycle, i. The net work of a cycle can be either positive or negative. Since the path a-b from left to right has a larger area beneath it than does the path b-a, the enclosed area is positive, and the cycle is said to be a power cycle.

Had the state point moved along the lower path in going from a to b, the positive work would have been the smaller, and the net work would have been negative; this is called a reversed or refrigeration cycle. Consider the four process cycle of Figure 4. There are four processes, some of which result in positive work, and some result in negative work. The net work is represented in the figure by the enclosed area.

The net work can be expressed as the sum of four work terms, each representing a positive or a negative number. Of course, four is chosen arbitrarily; there can be any number of processes in a given cycle. Let us analyze the Otto cycle depicted in Figure 4. This is a four process cycle comprising two adiabatic and two isochoric processes.

Since isochoric, or constant volume, processes have no volume change, the work calculated from 4. On the other. The cyclic work for the Otto cycle is the sum of W12 and W34; thus,. The first term on the right of 4. The second term is positive work and is the larger term; thus, the net work is positive, and the Otto cycle is a power cycle. Referring to Figure 4. The system is a perfect gas confined in a cylinder with a piston as an end wall; then 4.

Studying 4. Since the work processes and of the Otto cycle are adiabatic, there is no heat transfer to or from the system; thus, only work affects the amount of stored energy in the system.

By comparing corresponding terms in 4. One could also observe that there are internal changes in processes and , but these are not associated with work. In these processes the internal energy change is effected only by the heat transfers Q2T, and Q4i. Since heat transfer alone changes the internal energy in these processes, we can write.

Although 4. If the system comprised liquid, vapor, solid or a combination of these, 4. The principle observed is that, in the absence of heat transfer, work alone affects the level of stored energy in the system.

To generalize we can write. The principle expressed in 4. Each term in 4. We can observe that the cyclic integral of any property is zero.

This is easily shown for any cycle, but we shall write the cyclic change of internal energy as a sum of integrals; this is. Substituting 4. Replacing the work terms by means of 4. The principle can be shown to be true for any other cycle as well. The differential equation corresponding to 4. This statement of the first law has been derived from consideration of the Otto cycle, but it does not relate to any particular cycle; thus, it is a perfectly general statement governing changes of system internal energy.

It is general in application because it is really a statement of the principle of the conservation of energy applied to a system. The meaning of 4. The Rankine cycle is an example of a four process cycle. This is the most basic power plant cycle. The mechanical components needed for the cycle are depicted in Figure 1. The processes are shown in Figure 4. The cycle comprises process , an adiabatic expansion in a turbine; process , an isobaric compression cooling in a condenser; process , an adiabatic compression of liquid; and process , an isobaric expansion heating in a boiler.

The system is a fixed mass of water or other working substance, which flows around through the several mechanical components and undergoes changes of state inside each of them. The cyclic work for the Rankine cycle is the sum of the works for the processes, viz. WI2 and W34 represent works for adiabatic processes; thus, for a unit of mass in the flowing system, we can apply 4. The isobaric or constant pressure work of processes and is determined from 4. If the working substance is steam, the work of the cycle is calculated by substituting values of specific enthalpy found in Appendix A.

To estimate h4 - h3, an equation like 3. Such an equation is easily developed from 2. Setting dQ equal to zero and writing the terms of equation 4. The enthalpy difference h4 - h3 is the magnitude of the pump work and includes flow work as well as moving boundary work.

Moving boundary work is the reversible work mode that most frequently occurs in practice. It is calculated using 4.

The integral sign in 4. The very slow process is termed a quasistatic process. A quasistatic process can be reversed because there are no losses within the fluid due to fluid friction. In addition to moving boundary work on or by a compressible system, Reynolds and Perkins 8 and Zemansky and Dittman identify a number of reversible work modes used to describe other work processes occurring in nature. These are: the extension of a solid, the stretching of a liquid surface, changing the polarization of a dialectric material by an electric field, and changing the magnetization of a magnetic material by a magnetic field.

A detailed exposition of the aforementioned reversible work modes is presented by Reynolds and Perkins and Zemansky and Dittman. Several reversible work modes could conceivably occur in the same thermodynamic system.

Each additional work mode would then add an additional independent variable, thus increasing the number of properties required to establish the state of the system. The state postulate mentioned in Chapter 1 requires that the number of independent variables be equal to the number of reversible work modes plus one. Each work mode provides an additional way for energy to flow in or out of the system; the extra variable required by the 'plus one' part of the statement refers to either heat transfer or irreversible work, the latter being the equivalent of heat transfer.

Reversible moving boundary work was mentioned in the previous section. A reversible process was described as one that could be reversed, e. A reversible process is ideal and is never realized in practice; however, reversible processes often model reality with sufficient accuracy to be of practical value, e. Some processes are clearly irreversible. For example, when an electric motor turns a stirrer in a liquid, there is no way for the stirred fluid to reverse the flow of energy, so that an equal amount of work is done by the fluid on the motor.

Irreversibility is introduced into work processes by means of some non-ideal feature of nature. Some examples of non-ideal characteristics are friction, uncontrolled expansion of gases, heat transfer with a temperature difference, magnetization with hysteresis, electric current flow with electric resistance, spontaneous chemical reaction and mixing of gases or liquids having different properties.

According to Moore , friction between solids in contact, results from the interaction of roughness asperities of the two surfaces which results in local welding, shearing and ploughing of harder asperities into the softer material. The product of the tangential frictional force and the relative displacement measures the irreversible work, and this work results in an equal increase of internal energy of the two materials involved. Since a dissipative process of this sort cannot be reversed to transfer work back to the surroundings, it is clearly an irreversible process.

Fluid motion involves the sliding of one layer of fluid upon the other in a manner similar to the sliding of two solids in contact, and the result is fluid friction. Whitaker formulated the expressions for the rate at which irreversible work is done on each element of fluid per unit volume. The resulting function is called viscous dissipation and is particularly intense where high gradients of velocity exist in fluids, e. Another site of high viscous dissipation is within small vortices or eddies generated by turbulent flows.

A nozzle is a device, which by virtue of its design, guides a compressible fluid to an efficient expansion from a higher to a lower pressure and yields high fluid velocity at its exit. On the other hand, an uncontrolled expansion of a compressible fluid, such as occurs in a valve, results in the generation of many turbulent eddies and high viscous dissipation downstream of the valve. Irreversible work associated with friction between solid or fluid surfaces increases the internal energy of the system affected.

The work done by an external force or by the surrounding fluid resulted in a rise of thermal energy, which is a more random form of energy. The chapter includes a patient case, case discussion, and a complete didactic section that covers the definition and epidemiology of the disease and potential microvascular and macrovascular complications of uncontrolled diabetes and their recommended screening. Furthermore, the chapter highlights several common coexisting conditions in emerging adults with diabetes, including mood disorders, disordered eating, and other accompanying autoimmune diseases.

Critical issues in caring for emerging adults with diabetes are also discussed, including substance use, sexual health and preconception planning, financial barriers to transition and health insurance, preparation for changing living situations, and entering the work force or college. The chapter also provides multiple resources for the pediatric and adult health care team as well as the patient and family to help prepare and empower the emerging adult with diabetes for the transition to adult medical care.

Skip to main content. This service is more advanced with JavaScript available. Advertisement Hide. Authors Authors and affiliations Elizabeth O. Buschur Stephanie Lawrence. Chapter First Online: 26 November This is a preview of subscription content, log in to check access. Mortensen HB, Hougaard P. Comparison of metabolic control in a cross-sectional study of 2, children and adolescents with IDDM from 18 countries.

The Hvidore Study Group on childhood diabetes. Diabetes Care. Optimal control of type 1 diabetes mellitus in youth receiving intensive treatment.

J Pediatr. Persistent differences among centers over 3 years in glycemic control and hypoglycemia in a study of 3, children and adolescents with type 1 diabetes from the Hvidore Study Group. Effect of intensive diabetes treatment on the development and progression of long-term complications in adolescents with insulin-dependent diabetes mellitus: DIABETES control and complications trial. Diabetes control and complications trial research group. Google Scholar. The relationship of glycemic exposure HbA1c to the risk of development and progression of retinopathy in the diabetes control and complications trial.

Effect of glycemic exposure on the risk of microvascular complications in the diabetes control and complications trial—revisited.

Association between adherence and glycemic control in pediatric type 1 diabetes: a meta-analysis. Early risk factors for nonadherence in pediatric type 1 diabetes: a review of the recent literature. Curr Diabetes Rev. Facilitating access to glucometer reagents increases blood glucose self-monitoring frequency and improves glycaemic control: a prospective study in insulin-treated diabetic patients.

Diabet Med. Assessment of psychosocial variables by parents of youth with type 1 diabetes mellitus. Diabetol Metab Syndr. Borus JS, Laffel L. Adherence challenges in the management of type 1 diabetes in adolescents: prevention and intervention. Curr Opin Pediatr.

Economic status and clinical care in young type 1 diabetes patients: a nationwide multicenter study in Brazil.

Acta Diabetol. Changes in treatment adherence and glycemic control during the transition to adolescence in type 1 diabetes. Illness identity in adolescents and emerging adults with type 1 diabetes: Introducing the illness identity questionnaire. Standards of medical care in diabetes summary of revisions. Group DP. Incidence and trends of childhood type 1 diabetes worldwide — Diabetic Med. CrossRef Google Scholar. Incidence of type 1 and type 2 diabetes in adults and children in Kronoberg, Sweden.

Diabetes Res Clin Pract. Time trends and gender differences in incidence and prevalence of type 1 diabetes in Sweden. Thirty years of prospective nationwide incidence of childhood type 1 diabetes: the accelerating increase by time tends to level off in Sweden. Prevalence of and trends in diabetes among adults in the United States, — An epidemiologic profile of children with diabetes in the U. The burden of diabetes mellitus among us youth: prevalence estimates from the search for diabetes in youth study.

Assessment of diabetes-related distress. Psychological characteristics of adults with IDDM. Comparison of patients in poor and good glycemic control. Family function, stress, and locus of control. Relationships to glycemia in adults with diabetes mellitus.

Arch Fam Med. Stress and coping in relation to metabolic control of adolescents with type 1 diabetes. J Dev Behav Pediatr. Psychiatric illness in diabetes mellitus. Relationship to symptoms and glucose control. J Nerv Ment Dis. Fitzcarrald Cusco - Canas Ancash - Mcal. Asimismo, las diferencias son notorias entre las zonas de la sierra 23 por mil y la selva 25 por mil con respecto a las de la costa 22 por mil y a la de Lima Metropolitana 11 por mil Sin embargo, en la selva no se observan cambios favorables De acuerdo al Censo Nacional , el Entre las adolescentes quechuas y aymaras, son madres el A partir de entonces, esta brecha se incrementa a medida.

Cabe destacar que el Como se aprecia en la Tabla 14, el En segundo lugar se encuentran los 77, estudiantes aymaras 1. Es decir, considera como rurales a los centros poblados de hasta viviendas. Para mayor detalle ver Anexo 1. Para mayor detalle ver Tabla 14 del Anexo 2.

Datos tomados de Andina abril Acceso web julio Las escuelas con las mayores tasas de retiro son las que tienen predominancia de estudiantes quechuas urbano y rural , aymaras rural y aguarunas. Por lo general, las diferencias por sexo no superan los tres puntos porcentuales.

Los valores mayores a cero implican que la tasa de los varones es mayor que la de las mujeres. Mientras que el Para mayores detalles ver la Tabla 25 del Anexo 2. Nuevamente, las escuelas candoshis destacan porque ninguna de las tres aulas disponibles se encuentra en buen estado. Todas las escuelas donde los estudiantes provienen de las etnias cashibo, yagua, yanesha y yine no cuentan con ninguno de tres servicios. A nivel nacional, el Los pasos que se han dado, en Amazo-.