Two types magnets are in use today: the electromagnet and the ____________________ magnet.
Fill in the blank(s) with the appropriate word(s).
permanent
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Se debe preparar un informe de inspección escrito, fechado y firmado _____.
a. diariamente b. semanalmente c. mensualmente d. anualmente
The tubes that carry the ova from the ovaries to the uterus are called the _____
a. oviducts c. vulva b. urethra d. cervix
A series of experiments were conducted by passing 40°C air over a long 25-mm-diameter cylinder with an embedded electrical heater. The objective of these experiments was to determine the power per unit length required to maintain the surface temperature of the cylinder at 300°C for different air velocities (V). The results of these experiments are given in the following table:
(a) Assuming a uniform temperature over the cylinder, negligible radiation between the cylinder surface and surroundings, and steady-state conditions, determine the convection heat transfer coefficient (h) for each velocity (V). Plot the results in terms of h (W/m2•K)?vs. V (m/s). Provide a computer-generated graph for the display of your results, and tabulate the data used for the graph.
(b) Assume that the heat transfer coefficient and velocity can be expressed in the form h = CVn. Determine the values of the constants C and n from the results of part (a) by plotting h vs. V on log-log coordinates and choosing a C value that assures a match at V = 1 m/s and then varying n to get the best fit.
What type of refrigerants are normally used in CO2 cascade refrigeration systems?
A) HFC refrigerant mixed with CO2 in both systems B) HFC refrigerant in the high-temperature system and CO2 in the low-temperature system C) CO2 refrigerant in the high-temperature system and HFC refrigerant in the low-temperature system D) CO2 refrigerant in both the high- and low-temperature systems