With an unfocused transducer, for which of the exposures listed here are there no confirmed sig­nificant biological effects in mammalian tissue?

1. Biological studies of the cytoskeleton have shown:

 

a. ultrasound increases the risk of cavitation

b. ultrasound-induced changes are temporary

c. ultrasound produces long-term tissue damage

d. ultrasound increases the risk of tissue hyper­plasia

2. The use of contrast agents in diagnostic sonography:

a. has induced cell changes

b. may increase the risk of cavitation

c. demonstrates a rapid increase in tissue temperature

d. determines the conditions under which thermal effects occur

3. Limiting the exposure time to a fetus is an example of:

a. Snell’s law

b. mechanical index

c. ALARA principle

d. Huygens principle

4. Experimentation on living tissue in an artificial environment describes which of the following?

a. in situ

b. in vivo

c. ex situ

d. ex vivo

5. Heat is most dependent on which of the following intensities?

a. SPTP

b. SATP

c. SATA

d. SPTA

6. Pulses can induce cavitation in mammals with a peak intensity exceeding:

a. 10 MPa

b. 20 MPa

c. 10 W/cm2

d. 2000 W/cm2

7. Higher intensities are necessary to produce bioef­fects with a(n):

a. focused transducer

b. unfocused transducer

c. multifrequency transducer

d. three-dimensional transducer

8. Which type of cavitation involves the microbub­bles already present in tissues?

a. stable

b. spatial

c. thermal

d. transient

9. With an unfocused transducer, for which of the exposures listed here are there no confirmed sig­nificant biological effects in mammalian tissue?

a. 1 W/cm2

b. 1 mW/cm2

c. 100 W/cm2

d. 100 mW/cm2

10. The average intensity during the pulse repetition period defines:

a. spatial average

b. temporal average

c. spatial average–pulse average

d. spatial average–temporal average

find the cost of your paper

Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator

1. (a) Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator: (i) series-connected, (ii) shunt-connected and (iii) compound-connected.   (b) State one purpose for which….

what happens if the resistance in series with the shunt field of a DC motor is increased in value

1. Sparking at the trailing edges of the brushes in a DC machine is usually prevented by fitting   (a) copper gauze brushes (b) a compensating winding (c) a compound….

Calculate the synchronous speed of a 10-pole three-phase machine connected to a 50 Hz supply.

1. The generator characteristic shown in Figure 9.28 is for a   (a) shunt machine (b) series machine (c) differentially compounded machine (d) cumulatively compounded machine 2.The speed of a….