A BIOLOGICAL BASED HYSGROSCOPIC ACTUATOR EXPLORING THE MECHANICAL BEHAVIOUR OF BACILLUS SPORES THROUGH THE DESIGN OF FOLDING STRUCTURES
MA Design and Emergence School of Architecture Plannig & Landscape Newcastle University Author Johan Vanesa Torres Supervisor Dr. Martyn Dade-Robertson August 2015
001
THE PROBLEM Introduction Research Context
002
RESEARCH ANALYSIS
001
002 006
011
Newton’s Laws of Motion and work done
012
Mechanical Actuator vs Bacillus Spores
016
Comparative Scale Analysis
024
003
ANALOGUE PROTOTYPING
031
Folding surfaces and skeletons: Motion, deformation and scale-use
032
Experimenting with elastomers: Materiality
072
004
DEVELOPING A MATERIAL SYSTEM
087
Bacillus spores’actuator design strategies
088
Designing through building
098
Modular organization
132
005
CASE OF STUDY
006
139
SUMMARY AND RECOMMENDATIONS FOR FURTHER STUDY
153
BIBLIOGRAPHY
157
001
THE PROBLEM
002
INTRODUCTION
Chapter 001
The Problem
003
In response to the growing concern of sustainability in different fields, including Architecture, designers have started to develop responsive systems capable of adapting to environmental conditions (Thun and Velikov, 2013). However, the approaches use mechanical systems and physical control mechanisms that are often expensive and high energy consuming (Khoo, Burry, J. and Burry, M., 2011). Recent approaches have started to explore new technologies, materials, methods and processes capable of delivering the design of responsive architecture without the need for sensors and actuators, or at least, considerably reducing their usage (Correa et al., 2013; Beites, 2013). To address this, material systems are explored and intrinsic material properties are exploited through the use of computational design and fabrication (Khoo, Burry, J. and Burry, M., 2011; Ruairi, Karagkiozi and Themistocleous, 2013). Active materials with energy-exchanging properties pose a huge potential in architecture. Examples of this are phase-changing materials which pose dense thermal behaviour having light weight, (Koi and Salim, 2013)and Shape Memory Polymers that have the capability of recovering their original shape from a deformation upon the application of a particular stimulus such as heat (Hu et al., 2012; Huang et al., 2012, p.55; Leng et al., 2011). The use of these engineered materials has been explored and used in the discipline of architecture; nevertheless, some novels materials informed by biological/ natural systems seem to have greater architectural potential. The case of the hygroscopic capacity of Bacillus Spores is one of them. These biological entities have raised the attention of the scientific community owing to their capacity to generate work as a respond to water gradients (Chen et al., 2014). According to Chen et al. (2014) Bacillus spores have the potential to serve as building blocks for stimuli-responsive materials with engineering applications as converters and actuators (Chen et al., 2014) Up to now, Bacillus spores have been explored since both scientific and engineering points of view through the development of water-driven engines and generators. Examples of this are a rotary engine that works as base for a miniature car that moves forward as the water in the car evaporates, and an oscillatory device that works as electricity generator harvesting water from evaporation to power a light source (Chen et al., 2015) Even though Bacillus spores have not been explored since an architectural point of view, their high energy density and water-responsive capability open a world of possible architectural applications. Additionally, Bacillus spores have the capacity to self-assemble into dense, submicrometre-thick monolayers on elastic substrates such as silicon microcantilevers and elastomers sheets (Chen et al., 2014). Since a design approach this feature defines the possible materiality of water-responsive architectural structures based on Bacillus spores. Supporting the ideas stated above, this research is focused on the development of new technology based on the mechanical and hygroscopic properties of Bacillus Spores, capable of both delivering the design of responsive and adaptive architecture as a way to contribute to the field of sustainable design, and going further, imagine and implement new realities. Specifically, it attempts to deliver the design of a water-responsive actuator that can be used in the creation of folding structures.
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A biological based hygroscopic actuator
Chapter 001
The Problem
005
This research is divided in six major chapters. The first chapter describes the issues, concerns and interests of the research, in addition, existing researches and gaps are exposed in this section. In the second chapter the mechanical work of BS is analysed and compared with an electrical actuator, the outcomes are exposed as diagrams. This section is followed by an analogue exploration of both geometric and materiality. The fourth chapter attempts to set the bases for the design of a material system based on the hygroscopic properties of Bacillus spores which leads to the development of a case of study that is exposed through drawings, diagrams and images in the fifth chapter. Finally the conclusions and further work are stated in the sixth section.
006
RESEARCH CONTEXT
Chapter 001
The Problem
007
Responsive Architecture and responsive systems Responsive architecture is today understood as the interaction and adaptation between natural and artificial systems. In order to achieve responsiveness in architecture, new methods of design and strategies are implemented [18 p.3]. Computer-controlled prototyping and manufacturing are design methods where complex relationship between the components of a system and the environment where this is deployed can be analysed and refined (Beesley, Kirosue and Ruxton, 2006; Ruairi, Karagkiozi and Themistocleous, 2013; Khoo, Burry, J. and Burry, M., 2011). Currently, responsiveness has been reached through the use of kinetic motion as a process of adaption to users’ needs and, sometimes, even to the environment. The majority of these approaches are developed using sensors, detectors, transducer and actuators (Addington and Schodek, 2005), in other words, mechanical systems and physical control mechanisms which incur high costs and energy consumption (Khoo, Burry, J. and Burry, M., 2011).These systems and mechanisms are generally heavy, rigid, composed of many pieces and complex computation is used to control them (Ruairi, Karagkiozi and Themistocleous, 2013). Due to the hurdles associated with these mechanical systems, recent approaches have started to develop new material systems that respond to environmental conditions. One example is the project “Hygroskin� where the elastic and hygroscopic behaviour of wood is exploited, creating a material system used in the development of responsive surface structures. These structures change their morphological configuration according the humidity levels, providing a responsive change through passive actuation (Correa et al., 2013). Beites, S. (2013) is also currently developing another project supporting the idea of responsiveness and adaptation in architecture through the use of a passive system. This project aims to develop a SMPs actuator capable of being used in the development of deployable structures. The focus of the research is on a passive material system with the capacity to deploy without the need of embedded sensors and actuators when a specific temperature is reached owing to the intrinsic response capabilities of the material (Beites, 2013). The growing concern of sustainability in different fields, including Architecture, has spurred designers to research and develop responsive systems capable of adapting and even improve environmental conditions. Recent approaches have started to make use of biological systems as base for new materials and technologies. Although it is not a widely explored subject in architecture and there are many gaps that need to be bridge, these new technologies hold out great promise for the creation of more environmental designs.
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A biological based hygroscopic actuator
Bacillus spores as biological base for stimuli responsive actuators In this research the mechanical properties of Bacillus Spores are explored and scaled up into an architectural scale in an attempt to set the basi s for the design and manufacturing of a stimuli responsive actuator. Owing to the lack of access to Bacillus spores and practical knowledge related to the biological world, this research is based on existing Bacillus spores’ data. The following paragraphs expose in general terms –as this is an architectural research rather than merely scientific- the most important features of these biological systems. Bacillus spores are dormant cellular structures with the property of surviving under unfavourable environmental conditions (Nicholson et al., 2015; Sahin et al., 2012). Despite their dormancy state, spores are not entirely static. Spores dynamically expand and contract in response to increases and decreases in relative humidity (RH) exhibiting hygroscopic properties (Chen et al., 2015; Westphal et al., 2002; Sahin et al., 2012). These water responsive structures also manifest high energy density with interesting architectural, robotics and energy harvesting applications (Chen et al., 2015). According to Chen the mechanical response of Bacillus spores to humidity levels exhibits an energy density of 10MJ m-3 which is two orders higher than other stimuli responsive materials such as Shape Memory Polymers and Piezoceramics (Chen et al., 2014). This feature makes evident the impressive capacity of Bacillus spores to generate work.
Bacillus spores suspension Elastomer sheet
-RH
+RH
Fig 1 Diagram representing the curvature on elastomer sheets when the relative humidity changes.
30% RH
90% RH
Fig 2 Displacement of the elastomer sheet according to changes in relative humidity. Image taken from: Chen et al (2014)
Other important attribute of Bacillus spores is their capacity to self-assemble into dense, submicrometre-thick monolayers on elastic substrates such as elastomer sheets and silicon microcantilevers (Chen et al., 2014). In architecture, such a characteristic could lead to the design of bio-hybrid hygromorph actuators (Chen et al., 2014), supporting the creation of passive mechanisms and responsive structures. Additionally, Bacillus spores exhibit a high reversibility and relatively fast response of spore monolayers to cyclical variations in relative humidity. The results obtained from the experiments conducted by Chen et al. (2014) show how after one million cycles increasing and decreasing relative humidity the variations in deflection and surface stress were slightly reduced, manifesting high reversibility in the response of the monolayer. Other important feature is the fast mechanical response of the spores. When they are exposed to humidity their respond is approximately 0.4s, and with water release around 0.5 s (Chen et al., 2014). Even though Bacillus spores have not been used in an architectural context the experiments conducted by Chen et al. (2014) in the research “Bacillus spores as building block for stimuli responsive materials and nanogenerators” demonstrate the potential of Bacillus spores in the creation of a high-energy-density stimuli-responsive material. In the experiment an energy-harvesting device was created which remotely generates energy from a body of water. A rectangular Bacillus subtilis spore’s latex rubber sheet was connected to an electromagnetic generator next to a body of water. With the alternation of moisture in the air the spore based rubber sheet rotated the magnet delivering an average power of 0.7 micro watts, which is comparable to vibrational energy harvesters (Chen et al., 2014).
Chapter 001
The Problem
009
As it is previously exposed, Bacillus Spores have great mechanical properties and they could work as base for stimuli responsive materials, however, in an architectural context there are different constraints such as biosecurity and the spores cycle of live that need to be taken into account at the moment of delivering an architectural response. It is important to emphasise that although the mentioned features are not widely researched in this investigation, they need to be taken into account in further explorations. In overall, as with every novel and potent technology there are many gaps that need to be bridged, and blank spaces that need to be filled. Nevertheless, the use of Bacillus spores as biological base in the creation of stimuli-responsive materials promises to be a not so far and utopic dream. In this sense, this research attempts to imagine, speculate and propose the use of this technology in an architectural context. In order to translate the mechanical properties of bacillus spores into an architectural language and scale, different folding patterns and properties are explored and analysed.
Folding structures / Origami “An architecture of folding is by definition an architecture of surface� (Cobb, 2011, p.11). This author refers to folding as a manipulative property of surfaces. Folding technique explores materials’ transformation from a single surface into a volume through the uses of a variety of techniques such as fold, press, crease, pleat, score, pull up, rotate, wrap and so on, however, this transformation must maintain the continuity of the material (Vyzoviti, 2010). Using folding as design strategy in the creation of an architectural system based on Bacillus spores seems to be a logic approach since Bacillus spores have the capacity to self-assemble into submicrometer-thick monolayers on elastic surfaces such as elastomers sheets. In this sense, the basic idea is to shape Bacillus spores elastic surfaces into volumes using folding as main strategy. Different folding techniques have been explored in architecture. One very well-known is Origami, the antique art of paper folding. Manipulating paper following Origami techniques provides richness and variability and, complex geometries are generated based on simple papers transformation. Three Origami patterns stand out due to their structural applications: Yoshimura pattern, Miura Ori pattern and Diagonal pattern. In these patterns the curves are formed by simple accordion folding and followed by a reverse fold (Buri and Weinand, 2008).
Fig 3 in order: basic technique, Yoshimura pattern, Miura Ori pattern and Diagonal pattern. Images taken from: Buri and Weinand, 2008.
In this research the concepts of folding and origami are used to generate complex geometries with highly elastic and motion capacities. The use of the methods and techniques developed during this research can deliver the design of folding structures of different scales and uses.
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A biological based hygroscopic actuator
002
RESEARCH ANALYSIS
012
NEWTON’S LAWS OF MOTION AND WORK DONE
In order to understand the capacity of Bacillus Spores to generate motion, it is important to consider the forces acting upon the mass that we want to move. Using the concept of Work done in combination with Newton’s Laws we can calculate a mass displacement in an inertial reference frame. In addition, the equations of constant acceleration are used to calculate the velocity and acceleration of the mass in motion.
Chapter 002
Research Analysis
013
Newton's Laws of Motion First Law
If the net force -the vector sum of all forces acting on an object- is zero, then the velocity of the object is constant.
F = 0 then a = 0 and v=0
Second Law
The second law states that the net force on an object is equal to the rate of change (that is the derivative) of its linear momentum p in an inertial reference frame. F = m.a
Third Law
All forces between two objects exist in equal magnitude and opposite direction. FAB= F-BA
F = force (Joules) a = acceleration (m/s2) v = velocity (m/s) m = masa (kg) *The concepts are taken from: http://www.physics.byu. edu/
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A biological based hygroscopic actuator
Work done In physics, a force is said to do work if, when acting on a body, there is a displacement of the point of application in the direction of the force. There are three key ingredients to work - force, displacement, and cause. In order for a force to qualify as having done work on an object, there must be a displacement and the force.
W= F . d . cos ()
W = work (Joules) F = force (Newtons) d = displacement (meters) = the angle between the force and the displacement
*The concepts are taken from: http://www.physics.byu. edu/
Chapter 002
Research Analysis
015
Equations of constant acceleration For an object that has an initial velocity u and that is moving in a straight line with constant acceleration a, the following equations connect the final velocity v and displacement s in a given time t. v=u+a.t s = 1/2 (u+v) t s = u . t + 1/2 a . t2 s = v . t - 1/2 a . t2 v2 = u2 + 2a. s
v = velocity (m/s) u = initial velocity (m/s) a = acceleration (m/s2) t = time (s) s = distance (m)
*The concepts are taken from: http://www.physics.byu. edu/
016
MECHANICAL ACTUATOR VS BACILLUS SPORES
An actuator is a type of motor that is responsible for moving or controlling a mechanism or system. In this research we are interested in uderstanding the linear actuator as it is the most used in an architectural scale. After calculating the work done by an specific actuator, this result is compared with the work done by a Bacillus Spores actuator.
Chapter 002
Research Analysis
017
Linear Actuator actions
Pushing / pulling
Tilting
Opening / closing
Data obtained from: SKF Actuator range catalogue. Avalaible at: http://www.skf.com/
Raising / lowering
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A biological based hygroscopic actuator
Mechanical linear actuator
5.63 cm
21.89 cm
7.59 cm
Work done
Assuming that a object displacement is horizontal, and using the SKF 500N ACME actuator specifications, we calculate the maximun work that this actuator can do.
W= F . d . cos (0) =500 x 0.3 =150 J
Actuator specifications Electric Linear Actuator SKF 500N ACME Maximun load = 500N Maximun speed = 10mm/s Maximun stroke lenght = 300mm
1cm
Chapter 002
Research Analysis
019
Bacillus Spores actuator As the Bacillus Spores (BS) work is measured in energy density, we need to compare the mechanical actutor with the BS actuator in terms of volume. To do this, we assume that the BS actuator will have the same volume as the mechanical actuator. 21.89 cm
5.63 cm
volume in meters = 0.0563x0.0563x0.2189 = 0.000693m3
Work done
Assuming that the BS actuator have a volume of 0.000693m3, the proportion rule (rule of three) is used to calculate the work done.
1m3 0.000693m3 Bacillus Spores Data Energy density = 10MJ-3. = 10.600.000 J-3 Energy density is the amount of energy stored in a given system or region of space per unit volume. Energy density concept taken from: C. Dillon. (2009, October). How Far Will Energy Go? - An Energy Density Comparison [online]. Available: http://www. cleanenergyinsight.org/interesting/how-far-will-yourenergy-go-an-energy-density-comparison/
10.600.000 J x
x = 7345 J
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A biological based hygroscopic actuator
Comparing mechanical actuator and Bacillus Spores actuator Calculating the force needed to move a mass of 20 tonnes with a constant acceleration of 0.0034m/s2
F=m.a = 20.000kg x 0.0034m/s2 = 68 N
Calculating BS force for an horizontal movement of 0.3m - as the mechanical actuator maximum stroke lenght-.
W=F.d
F=W/d = 7385 J / 0.3m = 24.483 N
Calculating the quantity of mass a that BS actuator can move with an acceleration of 0.0034m/s2.
F
BS act.
/F
mass
Bacillus Spores actuator data
= 24.483N / 68N = 360.04 mass a
Work done = 7345 J Mecanical actuator data Work done = 150 J Maximum stroke lenght = 0.3m Acceleration = 0.0034m/s2 Mass a = 20 tonnes Acceleration and mass are taken from the deployable Large Umbrella project for the courts of the Prophet's Holy Mosque in Abu Dhabi
Calculating the quantity of mass a that the mechanical actuator can move with an acceleration of 0.0034m/s2.
F
MECH act.
/F
mass
= 500N / 68N = 7.35 mass a
Chapter 002
Research Analysis
021
ANALYSIS SYNTHESIS
Mechanical actuator work
150 J The mechanical actuator studied can move 7 masses up to 0.3m
Bacillus Spores actuator work
7345 J The Bacillus Spores actuator could move 360 masses up to 0.3m
...
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A biological based hygroscopic actuator
Chapter 002
Research Analysis
023
Even though the mechanical work that can be generated by Bacillus spores is extremely powerful, there are limitations in scaling up the systems based on these biological entities. Thus far the experiments conducted using Bacillus spores have made use of thin latex strips of dimensions up to 1 cm x 10cm. Chen et al (2015)
024
COMPARATIVE SCALE ANALYSIS
To understand the scale in which a Bacillus Spores actuator could work, three kinetic/deployable systems within different architectural scales are studied. The horizontal displacement that could generate the Bacillus Spores actuator studied in the previous chapter is calculated and compared within the three different scales.
Chapter 002
025
Research Analysis
System 1 Facade panel of Al Bahr Tower, Abu Dhabi, UAE.
System 2 Umbrellas for the Piazza of the Prophet's Holy Mosque, Madinah, KSA.
System 3 Fan Footbridge Paddington, London, UK.
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A biological based hygroscopic actuator
System 1 Calculating the force needed to move a panel
F = m.a = 500kg x 0.0034m/s2 = 1.7N
Calculating displacement
W=F.d
d=W/F = 7385 J / 1.7N = 4320m
Analogy In the real life, the facade module needs to be moved 3m, in this sense, the Bacillus Spores actuator studied could move 1440 modules
Facade panel of Al Bahr Tower, Abu Dhabi, UAE. mass = 500kg acceleration = 0.0034 m/s2 Bacillus Spores actuator data Work done = 7345 J
Chapter 002
027
Research Analysis
System 2 Calculating the force needed to move an umbrella
F = m.a = 20,000kg x 0.0034m/s2 = 68N
Calculating displacement
W=F.d
Analogy
d=W/F = 7385 J / 68N = 108m
In the real life, a 14m movement is needed for the umbrella to open, in this sense, the Bacillus Spores actuator could move 7 umbrella systems
Umbrellas for the Piazza of the Prophet's Holy Mosque, Madinah, KSA. mass = 20000kg acceleration = 0.0034 m/s2 Bacillus Spores actuator data Work done = 7345 J
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A biological based hygroscopic actuator
System 3 Calculating the force needed to move a panel
F = m.a = 30,000kg x 0.0034m/s2 = 102N Calculating displacement
W=F.d
Fan Footbridge Paddington, London, UK. mass = 30,000kg acceleration = 0.0034 m/s2 Bacillus Spores actuator data Work done = 7345 J
d=W/F = 7385 J / 102N = 72m
Chapter 002
Research Analysis
029
ANALYSIS SYNTHESIS The Bacillus Spores actuator (653cm3) have such a incredible mechanical properties that could be used in the three scales studied. However, up to now, there is no any system in which such a quantity of spores has been used.
System 1
4320m
System 2
108m
System 3
72m
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A biological based hygroscopic actuator
003
ANALOGUE PROTOTYPING
032
FOLDING SURFACES AND SKELETONS: MOTION, DEFORMATION AND SCALE-USE.
Even though this research makes use of folding techniques as a form finding strategy, the interest lies in the possible motions that can be triggered using these folding patterns and their relation with different scales in architecture and design. Folding techniques were chosen as form finding strategy owing to its close relationship with the strain caused by Bacillus spores when are suspended on rubber latex sheets. The elastomer goes from a flat position to a concave posture.
Chapter 003
Analogue prototyping
033
01 PROTOTYPE
FOLDING SURFACE
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A biological based hygroscopic actuator
Position A
2,5cm
21cm
Position B
Motion Analysis
17cm
Pattern
29cm
Percentage of opening in X and Y axis
86%
27%
X Y
Chapter 003
Analogue prototyping
035
Deformation A
Deformation Analysis Deformation A
Deformation B
Static area
Deformation B
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A biological based hygroscopic actuator
Scale - Use Analysis Folding cover
Chapter 003
Analogue prototyping
037
02 PROTOTYPE
FOLDING SURFACE
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A biological based hygroscopic actuator
Position A 2,5cm
15cm
Position B 16cm
Motion Analysis Pattern
20cm
Percentage of opening in X and Y axis
84%
25%
X Y
Chapter 003
Analogue prototyping
039
Deformation A
Deformation Analysis Deformation A
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A biological based hygroscopic actuator
Scale - Use Analysis Folding cover
Chapter 003
Analogue prototyping
041
03 PROTOTYPE
FOLDING SURFACE
042
A biological based hygroscopic actuator
Position A 14cm
14cm
Position B 21cm
Motion Analysis Pattern
21cm
Percentage of opening in X and Y axis
34%
34%
X Y
Chapter 003
Analogue prototyping
043
Deformation A
Deformation Analysis Deformation A
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A biological based hygroscopic actuator
Scale - Use Analysis Folding lamp - modifies light beam-.
Chapter 003
Analogue prototyping
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04 PROTOTYPE
FOLDING SURFACE
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A biological based hygroscopic actuator
Position A 15cm
15cm
Position B 20cm
Motion Analysis Pattern
20cm
Percentage of opening in X and Y axis
25%
25%
X Y *Interesting movement in Z axis
Chapter 003
Analogue prototyping
047
Deformation A
Deformation Analysis Deformation A
Area where the force is applied
048
A biological based hygroscopic actuator
Scale - Use Analysis Facade shutter shades
Chapter 003
Analogue prototyping
049
05 PROTOTYPE
FOLDING SURFACE
050
A biological based hygroscopic actuator
Position A 2cm
19cm
Position B 33cm
Motion Analysis Pattern
22cm
Percentage of opening in X and Y axis
93%
13%
X Y
Chapter 003
Analogue prototyping
051
Deformation A
Deformation Analysis Deformation A
Deformation B
Deformation B
052
A biological based hygroscopic actuator
Scale - Use Analysis Lamp sculpture
Chapter 003
Analogue prototyping
053
06 PROTOTYPE
FOLDING SURFACE
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A biological based hygroscopic actuator
Position A 3cm
14cm
Position B 25cm
Motion Analysis Pattern
21cm
Percentage of opening in X and Y axis
88%
33%
X Y
Chapter 003
Analogue prototyping
055
Deformation A
Deformation Analysis Deformation A
Deformation B
Deformation B
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A biological based hygroscopic actuator
Scale - Use Analysis Individual - Group sofa
Chapter 003
Analogue prototyping
057
07 PROTOTYPE
FOLDING SKELETON
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A biological based hygroscopic actuator
Position A 0.5cm
26cm
Motion Analysis
Chapter 003
Analogue prototyping
059
Deformation A
Deformation Analysis Deformation A and B
Deformation B
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A biological based hygroscopic actuator
Scale - Use Analysis Hat-Umbrella
Chapter 003
Analogue prototyping
Scale - Use Analysis Scarf-Umbrella
061
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A biological based hygroscopic actuator
Scale - Use Analysis Spring Chair
Chapter 003
Analogue prototyping
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08 PROTOTYPE
FOLDING SKELETON
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A biological based hygroscopic actuator
Position A 3cm
26cm
Motion Analysis
Chapter 003
Analogue prototyping
065
Deformation A
Deformation Analysis Deformation A
Deformation B
066
A biological based hygroscopic actuator
Scale - Use Analysis Bow-Umbrella
Chapter 003
Analogue prototyping
Scale - Use Analysis Street furniture: chair and cover
067
068
A biological based hygroscopic actuator
Scale - Use Analysis Triangular chair
Chapter 003
Analogue prototyping
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09 PROTOTYPE
FOLDING SKELETON
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A biological based hygroscopic actuator
SYNTHESIS
Folding surfaces and skeletons After analysing different folding patterns and techniques, three prototypes stand out in terms of their motion, deformation or use. These properties could work as base for further development of a folding structure.
The most interesting feature of this pattern is the property of maintain its shape even if it is subjected to forces from different points.
Comparing with the others studied models, this pattern stands out owing to it has the major percentage of opening and closing size. In vertical 13% and horizontal 93%.
The most remarkable feature of this prototype is the fact that it can have two different uses: Furniture when it is close and a cover when is open.
Chapter 003
Analogue prototyping
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072
EXPERIMENTING WITH ELASTOMERS: MATERIALITY
After informing this research with different folding patterns the next step was to understand the materiality of the Bacillus Spores’ actuator. In scientific experiments elastomer sheets have been the substrate in which the Bacillus spores are suspended. This background leads the following exploration were plastic liquid is used to examine the possible shapes that can be generated.
Chapter 003
Analogue prototyping
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01 PROTOTYPE ELASTOMER SHEET
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A biological based hygroscopic actuator
Process The mould was made of modelling clay and covered by liquid plastic using a paint brush. Five layers were applied, after the third layer the liquid plastic was mixed with thickener to give it a more robust texture and give more thickness to the prototype.
Chapter 003
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Analogue prototyping
02 PROTOTYPE ELASTOMER SHEET
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A biological based hygroscopic actuator
Process A triangular pattern was substrated from a modelling clay circular base and the negative space obtained was used as the mould, Five layers were applied, after the third layer the liquid plastic was mixed with thickener to give it a more robust texture and give more thickness to the prototype.
Chapter 003
Analogue prototyping
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03 PROTOTYPE ELASTOMER SHEET
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A biological based hygroscopic actuator
Process This mold was created with the idea of giving a concave shape to a flat modelling clay surface. In this case four layers of liquid plastic were applied without using plastic tickenner
Chapter 003
Analogue prototyping
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04 PROTOTYPE ELASTOMER SHEET
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A biological based hygroscopic actuator
Process Four semi-circles were subtracted from a circular modelling clay mold. This was done with the idea of connecting panels to each semi-circle. In this case the Bacillus spores sheet would work as a node. Four layers of liquid plastic were applied without using plastic tickenner to build the prototype.
Chapter 003
Analogue prototyping
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05 PROTOTYPE
ELASTOMER + METAL
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A biological based hygroscopic actuator
Process Two metal strips were introduced in a rectangular mould. They were covered by a thick layer of liquid plastic remaining embedded in the elastomer prototype. The main objective of using both material was to explore how the motion created by the elastomer elasticity can be transferred into panels through the metal strips.
Rectangular sheet with metal strips perpendicular to the folding
Chapter 003
Analogue prototyping
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06 PROTOTYPE
ELASTOMER + METAL
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A biological based hygroscopic actuator
Process Two metal strips were introduced in a mountain shape mould. They were covered by 10 layers of liquid plastic mixed with plastic tickenner. The main objective of using both material was to explore how the motion created by the elastomer elasticity can be transferred into panels through the metal strips.
Rectangular sheet with metal strips parallel to movement
Chapter 003
Analogue prototyping
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A biological based hygroscopic actuator
004
DEVELOPING A MATERIAL SYSTEM USING BACILLUS SPORES’ ACTUATORS
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BACILLUS SPORES ACTUATORS’ DESIGN STRATEGIES The use of Bacillus spores in the creation of water responsive engines/systems is a novel topic, owing to this, the present research is constantly fed by new data and cutting edge approaches that enrich the design process. In this section the firsts Bacillus spores actuators’design ideas are exposed through diagrams, drawings and photos. Additionally recent data about bacillus spores are analysed and integrated into the research.
Chapter 004
Developing a material system using BSAs
Firsts design ideas Panels and actuators System of panels connected by a skeleton. The actuators are connected to the panels through metal strips embedded on them.
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A biological based hygroscopic actuator
Bacillus Spores new data A recent research -Jun 2015- conducted by Chen et al. (2015) at Columbia University investigates different design strategies to scale up nanoscale waterdriven energy conversion into evaporationdriven engines and generatos. The publicated paper shows a series of evaporaton-driven engines capable of generating electricity to light up LEDs and drive a miniature car using bacterial spores deposited on micrometre-thick plastic monolayers. The design strategies and the data exposes in the Columbia University research are analysed and integrated into the design ideas of the present research. The following images show two different mechanisms that make use of strips coated with Bacillus spores generating mechanical work when are exposed to changes in relative humidity.
Note: all the data and images are taken from “Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators�. Nature Communications.
Chapter 004
Developing a material system using BSAs
The firts figure shows an evaporation-driven oscilatory engine. The second image illustrates a rotatory engine. Note: all the data and images are taken from “Scaling up nanoscale water-driven energy conversion into evaporation-driven engines and generators�. Nature Communications.
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Important facts: - Bacillus spores strips can quadruple their length as the relative humidity changes from 30% to 80%.
Dry RH <30%
Humid RH >80%
- The time in which the strips respond to changes in humidity levels is approximately 3 seconds. Up to 4 times
- The range of motion reduces when loaded with increasing weight, however, remains significant even at load weights that are 50 times more than the strips. - The work density of a 4cm strip is approximatelly 17J kg-1, which is close to mammalian skeletal muscles.
Bacterial spores are deposited on micrometre-thick plastic films alternating their disposition in both sides of the tapes. In this way the movement can be made linear.
As a linear actuator, the Bacillus spores strips are able to push an object. The interesting feature of this technology is to understand how others movements can be generated using a strip linear actuator.
Note: the data is taken from â&#x20AC;&#x153;Scaling up nanoscale waterdriven energy conversion into evaporation-driven engines and generatorsâ&#x20AC;?. Nature Communications.
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More design ideas based on new data
Vertical actuator
The research publicated through the paper â&#x20AC;&#x153;Scaling up nanoscale water-driven energy conversion into evaporationdriven engines and generatorsâ&#x20AC;? has demonstrated how Bacillus spores actuators can be used in the design of devices that react to moisture. The outcome of such an interesting research works as base for the development of this project. In this sense, the design ideas for the Bacillus spores actuators have changed from an one layer device to a device formed by several strips layers.
Horizontal actuator
It is important to mention that in a vertical movement the potential energy has to be taken into account. Because of this, an horizontal actuator could be more efficient.
Actuator joints
Panel Element that connects the actuators to the structure Actuator
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Generating rotational movement using linear actuators From the folding analysis, an interesting feature was found: Applying a horizontal force to a three series diamond pattern triggers vertical movements in different angles that all together create a rotational movement.
8cm Plan - Closed
Horizontal force
13cm Plan - Open
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Images of the rotational movement triggered when a horizontal force is applied.
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Using Bacillus spores strips to trigger movement
Opening angle:
120째
90째
60째
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Bacillus spores actuator schematic image
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DESIGNING THROUGH BUILDING
This section is focused on the development of the previous design since a more industrialized perspective. In this sense, different kind of joins, panels and skeletons are explored. A key feature in the actuator design is the fact that applying a horizontal force to a three series diamond pattern, the actuator can go from a closed position to an open position through a rotational motion. The following prototypes are built with the main objective of designing a device that can trigger a rotational movement since the application of horizontal and vertical forces.
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01 PROTOTYPE
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30 cm
Pattern
This study model consists of a hard skeleton joined by pivot joints. The structure is joined all together using hard-static components.
28 cm
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Flat position
Pivot joint
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Semi-circle position / Top view
Semi-circle position / Front view
The built study model showed a great potential to generate motion in the horizontal axis, however, in the vertical axis it is mostly static. This means that when the model is in the semi-circle position and a force is applied, it just present an horizontal motion. In addition, the skeleton structure seems to be flimsy since it tends to easily move in the horizontal axis. From the analysis of this model is concluded that a stronger structure is needed and the static joints in the vertical axis need to be re-designed.
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02 PROTOTYPE
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30 cm
Pattern
This study model consists of a hard skeleton joined by hard panels and pivot joints. The differences between this model and the previous one are the panels connecting the structure and the quantity of pivot joins.
21 cm
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Flat position
Panels
Pivot joint
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Semi-circle position / Top view
Semi-circle position / Front view
As in the previous model, this prototype exhibits motion in the horizontal axis and in the vertical axis it remains static. The panels give to the structure more resistance and help to define the mountains and valleys, however, it seems that the modelâ&#x20AC;&#x2122;s movement is restricted as the panels are directly connected to the skeleton. From the analysis of this model is concluded that the panels are needed to give more resistance to the structure but the connection between them and the skeleton should be more elastic.
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03 PROTOTYPE
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28 cm
Pattern
This model is integrated by two layers: A main skeleton connected by pivot joints, and a supra-layer consisting in panels connected to the skeleton through soft hinge joints. The difference between this model and the previous one is that the panels are not directly connected to the skeleton, a new soft hinge is used to do this. Now the design present a hybrid design using soft and hard joints
22 cm
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Flat position
Panels Pivot joint
Soft hinge
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Semi-circle position / Top view
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Semi-circle position / Front view
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Semi-circle position / Back view
Semi-circle position / Left view
The model exhibits great horizontal motion and unlike the previous model, this shows slightly vertical movement. The panels connected through the textile give more elasticity to the structure and at the same time it gives resistance to the structure defining the mountains and valleys. From the analysis of this model is concluded that the soft connection between panels and the skeletons seems to be accurate for this design, but the hard pivot joints decrease the motion in the vertical axis
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04 PROTOTYPE
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30 cm
Pattern
As the previous model, this prototype is integrated by two layers: A main skeleton and supra-layer consisting in panels. Although in this model the hard pivot joints are still used, they now are connected each other using a hinge joint.
21 cm
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Flat position Panels Pivot joint
Soft hinge
Hinge connecting the skeleton
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Semi-circle position / Top view closed
Semi-circle position / Front view closed
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Semi-circle position / Right view closed
Semi-circle position / Right view opened
The model exhibits great horizontal and vertical motion. It can easily go from a flat position to a semi-circle position. And it can be opened and closed in the semicircle position. The panels connected through the textile give more elasticity to the structure. From a point of view it is positive since the actuator can be totally closed, however, depending of the textile used it can be extremely elastic making the structure a little weak. From the analysis of this model is concluded that the joints need to do two types motion: in the vertical axis using a hinge joint and in the horizontal axis using a pivot joint.
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05 PROTOTYPE
With Bacillus spores strips
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Pattern
This model consists in a skeleton connected through both hinge and pivot joints. Additionally it has panels connected through soft hinge to the skeleton and elastomer strips joined to two panels creating the mountains and valleys. In this model just two elastomer strips have been proposed, however, the quantity of strips will vary according to the work that need to be done. This means that if the actuator is going to move a heavier panel, it will need more Bacillus spores strips.
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SYNTHESIS
Designing joins and panels The manufacturing of the actuator using both hard and soft materials seems to be the most feasible option to obtain the desired motion. During the design process two types of joints were used: hinge and pivot. Those were used owing to laser cutting was the manufacturing proces available. However, in a more industrialised process the ball and socket joint would be more pertinent.
Ball and socket joint
Pivot joint
Hinge joint
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Pivot joint
Hinge joint
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Ball and socket joint substituting the pivot and hinge joints
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Actuator elements: Ball and socket joint Panels Textile layer/soft hinge Bacillus spores strips
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MODULAR ORGANIZATION Owing to the scale in which Bacillus spores strips can generate work, a way to design a kinetic folding structure is using modules that all together can generate the desire motion. From the previous study models it can be observed the different kind of motions and patterns that can be generated using a triangular module. Because of this, a triangular panel connected to the actuators is proposed in order to create folding modular structures.
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Modular organization design
Module top view cm
42
Static panel
Folding panel
Bacillus spores actuator
60cm
Module front view
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Module in 0° Relative Humidity <30
Module in 45° Relative Humidity >80 Examples of opening angles 30°
45°
60°
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Moduleâ&#x20AC;&#x2122;s elements 1 2 3 3.a 3.b 4 4.a 4.b
Static panel Folding panel Connector arm Static joint Rotational joint BS actuator BS strips Protector cover 2
1
3.a 3.b 3
4 4.a 4.b
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Modular structure examples Position A Relative Humidity <30
60°
Position B Relative Humidity >80 30°
45°
30°
45°
60°
30°
45°
60°
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CASE OF STUDY
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A moisture driven folding sculpture To exemplify the use of Bacillus spores’ actuators in folding modular systems a moisture driven sculpture is designed in the city of Caracas, Venezuela. This biological based piece of art will be located in ‘El Parque del Este’ - ‘The East Park’-, which is one of the most important recreation parks in the capital city having an area of 82 hectares.
East Park plan Intervention area
The concept of this design born from the idea of ‘water visualization’. Although we all live surrounded by water in any of its states -solid, liquid and gas-, we usually only visualize it in its most dense states which are liquid and solid. We are not conscious of its constant presence around us as water vapor This moisture driven sculpture seeks to physically represent through motion the constant but always changing presence of water in gas state that is always around us. The project is specifically located in ‘The water wall patio’which is an area consisting of a platform laying on a rectangular lagoon. This landscape has a imponent water wall as background. A key point in choosing this space to place the moisture driven sculpture is because the water wall is on just during 30min twice day. During this time the sculpture will be totally open due to the little drops blown by the winter falling on the sculpture, however, why does the sculpture keep moving after the water drops cessation? The simplest answer: vapour of water. Note: The relative humidity data was taken from the weather base website: http://www.weatherbase.com
Relative Humidity in Caracas Average morning relative humidity
%
Jan
Feb Mar Apr
93
91
90
91
May Jun Jul
Aug
Sep Oct
Nov Dec
91
93
92
94
May Jun Jul
Aug
Sep Oct
Nov Dec
63
70
68
71
91
92
92
92
Average evening relative humidity
%
Jan
Feb Mar Apr
63
59
57
61
67
67
70
67
In the above graphs can be seen how the RH varies from morning to evening giving an idea of how the hygroscopic properties of Bacillus spores can be used in this context to trigger motion in the moisture driven sculpture. In addition, it is important to higlight that RH changes before and after raining.
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Plan and section of ‘The water wall patio’
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cm
Modules
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Modulesâ&#x20AC;&#x2122;organization
3m
9m
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Zoom A. Position 1 RH <30%
Static joint/angle
120° 0°
Zoom A. Position 2 RH >80% 60° 45°
30°
30°
60°
These diagrams illustrate the panels’ position when the RH is below 30% and above 80%, however, the Bacillus spores' strain also varies when the RH is between 30% and 80%. This means that during this period the panels are opened in other angles generating other shapes.
45°
60cm
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Water wall plan with sculpture in position 2 RH > 80%
0
4m
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Moisture driven sculpture. Position 1
Moisture driven sculpture. Position 2
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Water wall section with sculpture in position 2 RH > 80%
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Moisture driven sculpture. Position 1
Moisture driven sculpture. Position 2
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Posi tio RH < n 1 30% Posi tio RH > n 2 80%
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MORE SPECULATION In the case of study a kinetic sculpture was developed, however, after further development Bacillus spores actuator could even be used in architectural contexts such as facades, walls and covers.
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SUMMARY AND RECOMMENDATIONS FOR FURTHER STUDY
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Concluision and further work
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The research was set out to explore the hygroscopic properties and mechanical behaviour of Bacillus spores since an architectural point of view in an attempt to develop new technology, methods and process that support the design of sustainable and responsive architecture. The study was focused on the capacity of Bacillus spores to generate motion; thereby the research has identified the Bacillus spores capacity to generate work, the morphology and motion of structures where Bacillus spores can be used, the scale, materiality and fabrication. The research has also established the basis for the development of a material system using Bacillus spores technology and a case of study has been developed to illustrate the use of the material system in a specific context. In architecture the most common way of controlling a mechanism or system is using mechanical linear actuators, however, they tend to be heavy, composed of many pieces and controlled by computers and motors having a huge impact in the environment due to, among others reasons, the energy consumption. Having this reality as background, the research used the method of comparison to understand how Bacillus sporeâ&#x20AC;&#x2122;s actuators could replace the use of linear actuators in structures presenting different kinds of motion. The data obtained from this analysis revealed the huge capacity of Bacillus spores to generate work. The Bacillus spores work done exceeds by more of 90% the work done by a mechanical linear actuator. However, even though this is an impressive number, it is important to considerer the way in which the Bacillus spores can be part of a material system considering their biological nature and scale. Bacillus spores have the capacity to self-assemble on elastomer sheets expanding and contracting depending on relative humidity, thus, producing the substrate movement. This feature is a key point in the election of exploring folding patterns and their motion through the construction of study models. A common point in most of the study models was the use of patterns with triangular shapes. However, some of the patterns stands out owing to their capacity to change of size when they are folded and unfolded and others patterns present the capacity to undergo forces showing changes in the morphology of the piece but not in the pattern itself. Additionally, this exploration worked as a speculative exercise illustrating the possible scales in which these folding structures can be used. The scale in which the Bacillus spores have been used up to now also defined the material exploration and was an essential point at the moment of setting up the design strategies. In scientific explorations elastomers sheets and strips have been used as deposition substrate for the spores. In accordance to this, the research explored the design and manufacturing of elastomers having greater interest in to understand how the elastomers could be integrated to other materials and, even more, how the elastomers could work as part of a material system. This exploration was conducted through study models discovering that it is feasible to use materials such as metals and textiles in combination with elastomers delivering the design of hybrid systems. Furthermore, the theoretical background reveals that the size of the elastomers containing the bacillus spores is constrained by the microscopic dimension of these biological entities, thus it seems that bacillus sporesâ&#x20AC;&#x2122; elastomers work better in small scales but repeatedly, almost like layers, rather than having just one in a bigger scale.
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Both the layered organization of the elastomers containing the bacillus spores and their capacity to generate work led to the creation of an actuator that works as part of a modular system. In this system each actuator is connected to a panel generating an individual motion but, all together produce a synchronized choreography. Although the modular system consists on repetitive panels, the use of different opening angles in the actuator and the unpredictable humidity relative changes drives a more complex and even random dance. The case of study developed in this research illustrates a possible use of this system through the creation of a moisture-driven kinetic sculpture. The development of this architectural research was both fed and, at the same time, limited by its biological background. Although some of the design constraints were generated through the analysis of the study models, other data related to the spores was obtained through papers and theoretical information. The lack of access to the raw material -the spores- that is an essential part of the material system limited the fully understanding of the possible motions. Additionally, owing to the cutting edge character of the Bacillus sporesâ&#x20AC;&#x2122; technology there is no a broader range of papers and examples that can be taken as basis for the research, thus this study makes use of speculations to generate design constraints. The design constraints generated through the study models, the theoretical data and speculations established the framework for the development of a series of design strategies used in the design of the actuator, nevertheless, there are other facts that need to be taken into account and need to be expanded in further exploration. First of all developing a digital model simulating the energy density of the bacillus spores; it would work to understand both the actuators individual behaviour and the system motion. Other important fact is the longevity of the system and the bacillus sporulation control. In addition, more research about biosecurity and how to implement it on the design is essential. Finally, it is important to stand out that this research set a series of design strategies that work as basis for further development of a bacillus spores based material system that could be used in an architectural scale. The form finding techniques, scales and materials are examples of the foundations already established by this research. Additionally, this study was conducted with a broader objective of speculating about the use of cutting edge technologies in an architectural context. This research sought to reveal a new word of possibilities where architecture and other fantastic disciplines are merged with one goal in common, to build a better word.
BIBLIOGRAPHY
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A biological based hygroscopic actuator. Exploring the mechanical behaviour of Bacillus spores through the design of folding structures MA Design and Emergence School of Architecture Plannig & Landscape Newcastle University Author Johan Vanesa Torres Supervisor Dr. Martyn Dade-Robertson August 2015