Transcript Main presentation title goes here.

STEM Community
Challenge
Dr Steve Dorney
16 July 2011
Plan for today
• Background
• Bay House School/Vestas/ISVR – siting wind turbines
• ALNS/ISVR Consulting/Creative Partnerships – room
acoustics
• The HESTEM “Project brief” document
• Have a go …
• Link to HESTEM curriculum change – environmental
engineering consultancy
• Future: energy management; waste management
2
Locating a wind turbine
• Loci – see worksheet
• Applying technical, legal and social criteria
• Design and build at scale on school site
• + real-life example/issue
• - measurable but invisible impact on school/community
• - no legacy
3
Room acoustics
• 3 way project
– Consulting experience for University students
– Free professional assessment of spaces
– Pupils involved in measurement, design and
implementation
4
Four projects undertaken
• Investigation of Speech Intelligibility in The BLA Room
The Hartley Library
• Investigation of the Acoustics of a Science Classroom
Mayfield School, Portsmouth
• Noise Impact Assessment at a Proposed Skateboard Park Site
Greatness Community Association
• Investigation of the Acoustics of a School Canteen
Admiral Lord Nelson School, Portsmouth
5
ALNS Stage 1 – measure/report
6
ALNS Stage 2 – upgrade
skills and knowledge
7
ALNS Stage 3 – design & test
8
ALNS Stage 4 – select, revise
and implement
9
Room acoustics
• Broad range of maths and science
• Applying technical, legal and social criteria in tangible
(audible!) scenario
• Realistic prototyping process
• + real-life example/issue
• + measurable and high impact on school/community
• + environmental and learning legacy
10
The sample HESTEM brief
• www.sonicwonders.org
Pressure (Pa)
Have a go …
Time (s)
Decay is exponential
Reverberation time: time for pressure to decay by a factor of
1000 (60dB)
RT60 = 3 x RT20
If it’s too long …
The reverberation time of St Paul’s cathedral
(at 500Hz) when empty of people is
A.
B.
C.
D.
3 seconds
7 seconds
11 seconds
15 seconds
Sabine’s formula
kV
R
A
where k  0.161 s m
A is the equivalent area of perfectly
absorbing material (in m2)
The internal volume of St Paul’s Cathedral is 152,000m3 and its
reverberation time when empty of people is 11 seconds. Calculate:
i.
The equivalent absorption area when the cathedral is empty
ii. The reverberation time when full (2000 people) where each person
has an equivalent absorption area of 0.4m2
The reverberation time of St Paul’s cathedral
(at 500Hz) when full of people is
A.
B.
C.
D.
Less than 4 seconds
Between 4 and 6
seconds
Between 6 and 8
seconds
Longer than 8 seconds
Predicting absorption area
Equivalent
absorption area,
A  S1α1  S2α2 
kV
A
where k  0.161 s m
R
Snαn
where a are absorption coefficients …
Material
Absorption coefficient, a
Cost
Carpet
0.05
£10 per m2
Ceiling tile
0.5
£40 per m2
Thick curtains
0.35
£7 per m2
Linoleum
0.02
£2 per m2
Seating
Equivalent absorption area
Cost
Plastic seats
0.1m2 each
£20 each
Upholstered seats
0.8m2 each
£55 each
Challenge 1
•
Estimate the volume of this room.
Challenge 2
•
The reverberation time of this room, if unfitted and unoccupied, would be 3
seconds, say. What is the most cost effective way of fitting it out (including
50 chairs) so as to halve the reverberation time (still unoccupied)?
Challenge 3
•
Acoustic ceiling tiles are chosen as the sole solution to halve the
reverberation time, and the headmaster needs to decide what
proportion of the ceiling to have treated. Find an expression for the
reverberation time as a function of cost and plot (sketch) the graph.
Of form y 
a
1  bx
3.5
Reverberation time (s)
3
2.5
2
1.5
1
0.5
0
0
2000
(for V=1350m3)
4000
6000
Cost (£)
8000
10000
Plan for today
• Background – community/uni links via STEM?
• Bay House School/Vestas/ISVR – siting wind turbines
• ALNS/ISVR Consulting/Creative Partnerships – room
acoustics
• The HESTEM “Project brief” document
• Have a go …
• Link to HESTEM curriculum change – environmental
engineering consultancy
• Future: energy management; waste management
19