If eight tubes of the size designated in Problem 21.13 are arranged in a vertical bank and the flow is assumed laminar, determine a. The average heat-transfer coefficient for the bank b. The...
A dewar flask, used to contain liquid nitrogen, is made of two concentric spheres separated by an evacuated space. The inner sphere has an outside diameter of 1 m and the outer sphere has an inside...
It is desired to concentrate species A from a dilute mixture of solutes A and B dissolved in liquid water using a porous membrane. The membrane contains cylindrical pores in uniform parallel array....
The moisture in hot, humid, stagnant air surrounding a cold-water pipeline continually diffuses to the cold surface where it condenses. The condensed water forms a liquid film around the pipe, and...
A single-pass, shell-and-tube heat exchanger will be used to generate saturated steam by cooling a hot CO 2 gas stream. In the present process, boiler feed water at 100C (373 K) and 1 atm (saturation...
A cell mono layer used in a tissue engineering scaffold adheres onto the top surface of a silicone rubber (polymer) sheet of 0.10 cm thickness, as shown in the figure below. The rectangular sheet is...
The table below presents equilibrium distribution data for four gaseous solutes dissolved in water, using air as the carrier gas: a. Using a spreadsheet to perform the calculations, prepare a graph...
A packed-bed tower is used for absorption of sulfur dioxide (SO 2 ) from an air stream using water as the solvent. At one point in the tower, the composition of SO 2 is 10% (by volume) in the gas...
Wastewater containing volatile species A dissolved in the water at a dilute inlet concentration of 0.50 gmole A/m 3 (c AL,0 ) is pumped into a well-mixed open holding pond at a volumetric flow rate...
A biosensor is a device that uses a biological mechanism to aid in the detection of a solute (A) within a mixture. Consider the hemispherical-shaped biosensor tip shown in the figure on page 529. The...
Consider the physical system shown in the figure on page 532. which represents a simplified scenario for the treatment of tumor (cancer) tissue. In this experiment, a slab of living tissue is in...
If the atmospheric microwave absorption coefficient γ varies with height z as γ = Ï Î²exp (-βz), Ï being the optical thickness of the entire...
A mass hanging from a spring oscillates with a period of 0.35 s. Suppose the mass and spring are swung in a horizontal circle, with the free end of the spring at the pivot. What rotation frequency,...
An avant-garde composer wants to use the Doppler effect in his new opera. As the soprano sings, he wants a large bat to fly toward her from the back of the stage. The bat will be outfitted with a...
The first and second laws of thermodynamics are sometimes stated as You cant win and You cant even break even. Do these sayings accurately characterize the laws of thermodynamics as applied to heat...
Two positive point charges q and 4q are at x = 0 and x = L, respectively, and free to move. A third charge is placed so that the entire three-charge system is in static equilibrium. What are the...
What are the strength and direction of the electric field at the position indicated by the dot in FIGURE EX23.3? Specify the direction as an angle above or below horizontal. 3.0 nC (+ 5.0 cm 5.0 cm...
a. An infinitely long sheet of charge of width L lies in the xy plane between x = -L/2 and x = L/2. The surface charge density is . Derive an expression for the electric field E at height z above the...
The cube in FIGURE EX24.7 contains negative charge. The electric field is constant over each face of the cube. Does the missing electric field vector on the front face point in or out? What strength...
The switch in FIGURE EX28.36 has been in position a for a long time. It is changed to position b at t = 0 s. What are the charge Q on the capacitor and the current I through the resistor (a)...
A packed tower is used to remove component A from a gas stream mixture containing 12.0 mole% A and 88.0 mole% inerts. The gas mixture is fed to the bottom of the tower, and the desired superficial...
A pilot-scale tower packed to a height of 6.0 ft with 5/8- inch ceramic Raschig rings is used to study the absorption of carbon disulfide (CS 2 , solute A) from nitrogen gas (N 2 ) into a liquid...
A natural gas stream with a total volumetric flow rate of 880 standard cubic meters (SCM) per hour (std m 3 /h), temperature of 40°C, and total system pressure of 405 kPa is contaminated with 1.0...
FIGURE P29.64 shows a mass spectrometer, an analytical instrument used to identify the various molecules in a sample by measuring their charge-to-mass ratio q/m. The sample is ionized, the positive...
Your camping buddy has an idea for a light to go inside your tent. He happens to have a powerful (and heavy!) horseshoe magnet that he bought at a surplus store. This magnet creates a 0.20 T field...
A 0.50-mm-diameter hole is illuminated by light of wavelength 550 nm. What is the width (in mm) of the central maximum on a screen 2.0 m behind the slit?
Find the focal length of the glass lens in FIGURE EX34.25. 24 cm 40 cm FIGURE EX34.25
Suppose a cameras exposure is correct when the lens has a focal length of 8.0 mm. Will the picture be overexposed, underexposed, or still correct if the focal length is zoomed to 16.0 mm without...
A capillary tube is immersed vertically in a water container. Knowing that water starts to evaporate when the pressure drops below 2 kPa, determine the maximum capillary rise and tube diameter for...
A large plate is pulled at a constant speed of U = 4 m/s over a fixed plate on 5-mm-thick engine oil film at 20°C. Assuming a half-parabolic velocity profile in the oil film, as sketched,...
Reconsider the helicopter in Prob. 13??38, except that it is hovering on top of a 2800-m-high mountain where the air density is 0.928 kg/m 3 . Noting that the unloaded helicopter blades must rotate...
Consider a heavy car submerged in water in a lake with a flat bottom. The drivers side door of the car is 1.1 m high and 0.9 m wide, and the top edge of the door is 10 m below the water surface....
A long, solid cylinder of radius 2 ft hinged at point A is used as an automatic gate, as shown in Fig. P11??9E. When the water level reaches 15 ft, the cylindrical gate opens by turning about the...
Determine the resultant force acting on the 0.7-m-high and 0.7-m-wide triangular gate shown in Fig. P11??15 and its line of action. 0.3 m. 0.7 m 0.9 m Water 0.7 m
A crane is used to lower weights into a lake for an underwater construction project. Determine the tension in the rope of the crane due to a 3-ft-diameter spherical steel block (density = 494 lbm/ft...
The average density of icebergs is about 917 kg/m 3 . (a) Determine the percentage of the total volume of an iceberg submerged in seawater of density 1042 kg/m 3 . (b) Although icebergs are mostly...
A 15-hp (shaft) pump is used to raise water to a 45-m higher elevation. If the mechanical efficiency of the pump is 82 percent, determine the maximum volume flow rate of water.
The velocity profile in fully developed laminar flow in a circular pipe of inner radius R = 2 cm, in m/s, is given by u(r) = 4(1 - r 2 /R 2 ). Determine the average and maximum velocities in the pipe...
Consider an air solar collector that is 1 m wide and 5 m long and has a constant spacing of 3 cm between the glass cover and the collector plate. Air flows at an average temperature of 45?C at a rate...
One of the important ways in which the Higgs boson was detected at the Large Hadron Collider was by observing a type of decay in which the Higgswhich decays too quickly to be observed directlyis...
An engineer proposes to use the mass-transfer equipment shown in the figure (next page) to prepare a water stream containing dissolved oxygen. Liquid water containing no dissolved oxygen is fed to...
A highly viscous liquid discharges from a large container through a small-diameter tube in laminar flow. Disregarding entrance effects and velocity heads, obtain a relation for the variation of fluid...
Hot water is to be cooled as it flows through the tubes exposed to atmospheric air. Fins are to be attached in order to enhance heat transfer. Would you recommend attaching the fins inside or outside...
A short brass cylinder (Ï = 8530 kg/m 3 , c p = 0.389 kJ/kg·K, k = 110 W/m·K, and α = 3.39 à 10 -5 m 2 /s) of diameter 8 cm and height 15 cm is initially at a...
Steam at 250C flows in a stainless steel pipe (k = 15 W/m.K) whose inner and outer diameters are 4 cm and 4.6 cm, respectively. The pipe is covered with 3.5-cm-thick glass wool insulation (k = 0.038...
The upper surface of a 50-cm-thick solid plate (k = 237 W/m·K) is being cooled by water with temperature of 20°C. The upper and lower surfaces of the solid plate maintained at constant...
Consider a 10-m-long smooth rectangular tube, with a = 50 mm and b = 25 mm, that is maintained at a constant surface temperature. Liquid water enters the tube at 20°C with a mass flow rate of...
The wall of a refrigerator is constructed of fiberglass insulation (k = 0.035 W/m·K) sandwiched between two layers of 1-mm-thick sheet metal (k = 15.1 W/m·K). The refrigerated space is...
A 2-m-long, 0.2-m-diameter cylindrical pine log (density = 513 kg/m 3 ) is suspended by a crane in the horizontal position. The log is subjected to normal winds of 40 km/h at 5°C and 88 kPa....
A 15-ft long strip of sheet metal is being transported on a conveyor at a velocity of 16 ft/s. To cure the coating on the upper surface of the sheet metal, infrared lamps providing a constant radiant...
Determine the view factors F 12 and F 21 for the very long ducts shown in Fig. P2173 without using any view factor tables or charts. Neglect end effects. Oso 50 (0) (b) -------- (c)
Determine the view factors from the very long grooves shown in Fig. P2162 to the surroundings without using any view factor tables or charts. Neglect end effects. (a) Semicylindrical (b) Triangular...
Consider a condenser in which steam at a specified temperature is condensed by rejecting heat to the cooling water. If the heat transfer rate in the condenser and the temperature rise of the cooling...
How does the log mean temperature difference for a heat exchanger differ from the arithmetic mean temperature difference? For specified inlet and outlet temperatures, which one of these two...
The temperature difference between the hot and cold fluids in a heat exchanger is given to be T 1 at one end and T 2 at the other end. Can the logarithmic temperature difference T lm of this heat...
A double-pipe parallel-flow heat exchanger is used to heat cold tap water with hot water. Hot water (c p = 4.25 kJ/kg·K) enters the tube at 85°C at a rate of 1.4 kg/s and leaves at...
A test is conducted to determine the overall heat transfer coefficient in a shell-and-tube oil-to-water heat exchanger that has 24 tubes of internal diameter 1.2 cm and length 2 m in a single shell....
A shell-and-tube heat exchanger is used for heating 10 kg/s of oil (c p = 2.0 kJ/kgK) from 25C to 46C. The heat exchanger has 1-shell pass and 6-tube passes. Water enters the shell side at 80C and...
Consider a heat exchanger that has an NTU of 4. Someone proposes to double the size of the heat exchanger and thus double the NTU to 8 in order to increase the effectiveness of the heat exchanger and...
Consider a heat exchanger that has an NTU of 0.1. Someone proposes to triple the size of the heat exchanger and thus triple the NTU to 0.3 in order to increase the effectiveness of the heat exchanger...
Water (c p = 4180 J/kgK) enters the 2.5-cminternal-diameter tube of a double-pipe counter-flow heat exchanger at 17C at a rate of 1.8 kg/s. Water is heated by steam condensing at 120C (h fg = 2203...
Cold water (c p = 4180 J/kg·K) enters the tubes of a heat exchanger with 2-shell passes and 20-tube passes at 20°C at a rate of 3 kg/s, while hot oil (c p = 2200 J/kg·K) enters the...
Derive the allowed combinations of charm C and electric charge Q for mesons and baryons in the simple quark model.
What would be the energy of a positron if it were emitted from the decay p 0 + e + of a proton at rest? If such an event were observed in the Super Kamiok and e detector, what would be the emission...
Consider a star moving with velocity in a circular orbit of radius R about the centre of a spiral galaxy. Calculate the dependence of on R for the following extreme cases. (a) The total mass of the...
Hot water at 60C is cooled to 36C through the tube side of a one-shell pass and two-tube passes heat exchanger. The coolant is also a water stream, for which the inlet and outlet temperatures are 7C...
Confirm eq. and the estimate for the rhinoceross kinetic energy below eq. by explicit calculation. Ep+p=2MPC = 3 x 10-10 JE 1877 MeV. kinetic energy = mv
It has been proposed that solar collectors could be deployed in space, and that the collected power could be beamed to Earth using microwaves. A potential limiting factor for this technology would be...
Given the Suns power output of 384 YW and radius 695500 km, compute its surface temperature assuming it to be a black body with emissivity one.
Prove analytically that the entropy of a two-statesystem? is maximized when p + = p ? = 1/2. S = -kB (p+ In p+ +p_ In p_) = -kB (P+ In p4 + (1 P+) In(1 P+))
In isobaric heating (and expansion), heat is added reversibly to a gas kept at constant pressure. Find the change in volume and entropy when a sample of an ideal, monatomic gas, initially at...
An SI engine, modeled as an ideal Otto cycle, runs at a compression ratio of 9.6:1 with a maximum cylinder volume (V 1 ) of 2 L and a corresponding displacement of 1.8 L. Combustion leads to a...
An example of a thermal-neutron fission reaction isn th + 235 U 139 Ba + 94 Kr + 3n. Perform the analysis of Example 18.1 for this case.
Show that an infinite, homogeneous reactor fueled with natural uranium (0.72% 235 U) and moderated by heavy water (D 2 O) can sustain a fission chain reaction. What is the optimal ratio of moderator...
Thermal neutrons wandering through biological tissue are most likely to be absorbed by 1 H, 12 C, or 16 O. If absorption is accompanied by emission of a single -ray, what are the -ray energies...
According to the text, roughly 1015% of lung cancer deaths in the US are due to radon exposure. Use the LNT model and average yearly effective dose from radon to estimate the cancer rate from this...
Consider the circumstances described in Problem 21.8, but now suppose that 2 < 0. Use the transformation defined in Problem 21.7 to show that there is a reference frame traveling at a speed v < c in...
Compute the power radiated in the visible range from the toaster oven coil radiating with a total power of 1500 W, as described in Example 22.1.
Determine the maximum concentration C of a solar concentrator satisfying T 4 = CI 0 , where I 0 is the solar constant, directly from the second law of thermodynamics and the surface temperature of...
The wind speed at any site can be written as the sum of its average v plus a fluctuating term that averages to zero, v(t) = v + v(t). Show that the effect of the fluctuations is always to make v 3 ...
Compute the energy density and power density in a steady wind at 8 m/s and at 16 m/s.
An entrepreneur claims to have devised a system for extracting thermal energy from the wind by cooling it. His device lowers the temperature of the air that passes through it by 1 C. He claims to...
The isothermal compressibility of a fluid is the relative change of volume with pressure at constant temperature = (1/V)V/p| T . Qualitatively describe and sketch the compressibility of water as a...
Estimate the power output possible for a hydroelectric dam with hydraulic head Z = 30 m, flow rate Q = 300 m 3 /s, and turbine efficiency 90%.
Estimate the energy content of a coal seam measuring 1 km 2 by 1 m deep. Estimate the electrical power output of a coal plant burning this fuel over one year, and the area required for a solar...
A 345 kV transmission line consisting of three conductors has a resistance per unit length of R =R/l = 0.0351/km, and an inductive reactance per unit length of L = L/l = 0.371 /km, as described in...
A beaker containing 400 g of water has 1200 J of work done on it by stirring and 200 cal of heat added to it from a hot plate. a. What is the change in the internal energy of the water in joules? b....
A guitar string has an overall length of 1.25 m and a total mass of 40 g (0.04 kg) before it is strung on the guitar. Once on the guitar, however, there is a distance of 64 cm between its fixed end...
A pipe that is open at both ends will form standing waves, if properly excited, with antinodes near both ends of the pipe. Suppose we have an open pipe 40 cm in length. a. Sketch the standing-wave...
Radiation shields are commonly used in the design of superinsulations for use in space and cryogenics applications. Write an essay on superinsulations and how they are used in different applications.
A baryon frequently encountered in particle physics experiments is known as the (Lambda). Its quark content is uds. Sometimes the decays by the process n, where n is a neutron (ddu) and is a...
The radius of Mars orbit around the Sun averages roughly R Mars 2.28 10 8 km. Assuming that the surface temperature is roughly uniform over the planets surface and constant over a Martian day, that...
The eccentricity of Mars elliptic orbit is roughly 0.0935. Estimate the range over which the solar constant and average surface temperature (in the uniform temperature blackbody approximation) vary...
Why does the efficiency of a silicon PV drop as it heats up? eq. (25.25). E- kBT In dE Egap Voc < SE dE gap E2 eE/kgT e
The absorption coefficient of silicon has a strong dependence on photon energy, as shown in Figure 25.16 For simplicity, consider an idealized material, material S, similar to crystalline silicon,...
What is the energy of sunlight (in units of W/m 2 at normal incidence)? Discuss how energy is destroyed when sunlight is converted to electricity by photo voltaic cells, by solar thermal electric...
A very thin silicon chip is bonded to a 6-mm thick aluminum substrate by a 0.02-mm thick epoxy glue. Both surfaces of this chip-aluminum system are cooled by air at 25C, where the convective heat...
A new type of porous material serves as food packaging film, as shown in the figure below. The film rests on a nonporous metal plate. The packaging film is 0.20 cm thick (2.0 mm). The food contains...
It is desired to diffuse a blue dye molecule (solute A) into a solid material (species B) near the surface of the material, as shown in the figure below. Initially, there is no dye in the solid (c Ao...
Consider the concentric tubular mass transfer device shown in the figure below. This device is designed to gradually introduce hydrogen (H 2 ) gas (species A) into a pure oxygen gas (O 2 ) inlet...