ME5524 Biofluid - Brunel University

objective 1: To understand and use Matlab software in the analysis of arterial waves.
objective 2: To understand how to implement the equations of wave intensity analysis and derive the relevant parameters.

Learning outcome 1: Writing technical reports and literature survey.
Learning outcome 2: a) Understand the principles of waves in flexible tubes.
b) Apply the analytical techniques on in vivo measurements.

Brief Description of the assessment:

The student will research the literature, the lecture notes, to answer the theoretical questions of the assignment (#1 below). Also, the student will use Matlab to analyse the data provided using the equation given in the lecture notes. The student will prepare and submit a report as described below

Assessment and marking criteria

1. Literature
a) Define and discuss wave intensity analysis and explain the advantages of this technique.

b) Research the literature extensively and report on research carried out at different location of the arterial system using wave intensity analysis (i.e, upper aorta, coronary artery, left ventricle, etc.) - provide details of no less than 4 sites. [10%]
c) Discuss briefly the effect of the aging process on typical values of wave intensity peaks.

2. Calculations and plotting
a) Plot measured, forward and backward pressures in a plot using different colour for each.

b) Plot measured, Forward and backward velocity in a plot using different colours for each.

c) Calculate and report wave speed using the PU-loop - produce a plot of the loop, highlighting the
linear part with a different colour.

d) Carry out WIA and plot the results of net intensity, forward and backward intensities using subplots (each intensity in a separate plot). From the backward WI plot please determine the arrival time of reflected waves.

e) Using the time determined in (4) and wave speed determined in (3), calculate the distance to the reflection site.

3. User Interface

Develop a user interface as described below

a. The layout of the interface should look like the one below, containing:

b. Button (A) to load data; when pressed a dialogue box (use "uigetfile" function) will appear on the screen in which you can browse and search for the data file. When the file is selected, the data will be loaded into MatLab and measured pressure and velocity will be plotted in the top graph against time (both at the same graph - use "hold") [5%]

c. Turn on the grid for this graph and show each waveform in a different colour. Use the "plotyy"- function to have 2 y-axes; one for pressure and one for velocity. Add appropriate labels to the axes.

d. Button (B) to perform the wave analysis; when button is pressed, graph 2 will show the PU-loop. Identify two points representing the initial linear part of the loop to calculate wave speed. When the two points have been selected (clicked), the program will calculate separated wave intensity, separated pressure and separated velocity in the background.

e. For graph 2, create a pull-down menu and write a code to plot the results (PU-loop, Wave Intensity, Separated Pressure or Separated Velocity) corresponding to the choice. When another option is selected from the pull-down menu, the graph should be updated and show the new plots accordingly

3. For all your calculations use the following equations.

dP_± = ±ρcdU_±

P⁺ (t) = P₀ + ∑^t_τ=0dP₊ (τ)

dP_± = 1/2(dP ± ρcdU)              P_-(t) = ∑^t_τ=0dP_ (τ)

dU_± = 1/2 (dU ± dP/ρc)           U_±(t) = ∑^t_τ=0^tdU_± (τ)

dI_± = ± 1/4ρc (dP ± ρcdU)²

Attachment:- Mechanics.rar