# Ch. 5: Intensities Flashcards

1
Q

Spatial refers to…

A

location, distance or space.

2
Q

Define ‘peak’.

A

maximum value

3
Q

Define ‘average’.

A

mathematical middle value

4
Q

Temporal refers to…

A

all time, transmit (pulse duration), and receive.

5
Q

Pulsed refers to…

A

transmit time only (ignoring listening time).

6
Q

What is spatial peak intensity?

A

The beam’s intensity at the location where it is at its maximum; I-sp

7
Q

What is spatial average intensity?

A

The average intensity across the beam’s entire cross-sectional area; I-sa

8
Q

Spatial peak intensity is always ___ than the spatial average intensity.

A

higher

9
Q

What is temporal peak intensity?

A

The intensity of the beam at the instant in time of its maximal value; I-tp

10
Q

What is maximum intensity?

A

The average intensity during the most intense half-cycle; I-max or I-m

11
Q

What is pulse average intensity?

A

The average intensity during the pulse duration (transmit only); I-pa

12
Q

What is the temporal average intensity?

A

The average intensity during the entire pulse repetition period (transmit + receive); I-ta

13
Q

Of the four temporal intensity measurements, which has the highest value?

A

temporal peak (I-tp) which is slightly higher than I-max.

14
Q

Which is the lowest of the temporal intensity measurements?

A

temporal average (I-ta)

15
Q

Temporal intensities from largest to smallest?

A

I-tp, I-max, I-pa, I-ta

16
Q

Which intensity is measured at the location where intensity is maximum and at the instant in time when the most powerful part of the pulse passes?

A

I-sptp

17
Q

Which intensity is measured at the location where intensity is maximum, averaged over the pulse duration?

A

I-sppa

18
Q

Which intensity is measured at the location where intensity is maximum and averaged over all time?

A

I-spta

19
Q

Which intensity is measured over the entire cross-sectional area of the sound beam and over all time?

A

I-sata

20
Q

Intensities may be reported in various ways with respect to…

A

time and space.

21
Q

The different measurements of intensities are important in…

A

the study of bioeffects.

22
Q

Which is the most relevant intensity with respect to tisue heating?

A

I-spta

23
Q

Intensities are reported in units of…

A

W/cm^2

24
Q

Peak measurements are ___ than average measurements.

A

larger

25
Q

Which intensity has the highest value?

A

I-sptp

26
Q

Which intensity has the lowest value?

A

I-sata

27
Q

What number describes the spread of a beam in space?

A

the beam uniformity coefficient (aka SP/SA factor)

28
Q

The beam uniformity coefficient (SP/SA factor) is reported in units of…

A

Trick question! It’s unitless, with a value of 1 or greater.

29
Q

What describes the relationship of beam intensities with time?

A

The duty factor

30
Q

The duty factor is reported in units of…

A

Trick question! It’s unitless, with a value between 0 and 1.

31
Q

In continuous wave u/s the pulse average and temporal average are the ___.

A

same. So SPTA = SPPA and SATA = SAPA.

32
Q

When pulsed and continuous wave sound beams have the same SPTP intensities, the continuous wave beam has the ___ SPTA intensity.

A

higher

33
Q

When pulse and continous wave sound beams have the same SATP intensities, the continuous wave beam has the ___ SATA intensity.

A

higher

34
Q

I-tp is the ___ intensity in time.

A

maximum

35
Q

I-m intensity is averaged over the most intense ___.

A

half-cycle

36
Q

I-pa is averaged during the ___.

A

pulse duration

37
Q

I-ta is averaged during the ___.

A

pulse repetition period

38
Q

I-sp is the ___ in space.

A

maximum

39
Q

I-sa is averaged over the ___.

A

cross-sectional area of the beam

40
Q

Rank the intensities from largest to smallest.

A

SPTP, I-m, SPPA, SPTA, SATA