The Architectural Object of Cleansing

The Architectural Object of Cleansing

Designing the experience for changing the hygenic lifestyle in Potosi

Alison Siying Chen Architecture Association Year 3 Experimental Unit 17

Mine Activities & Hygenic Crisis The Pollution of landlord water and water scarcity of great concern

Thesis The project aims to use the Vaulting intelligence and Earth Casting technique to create the architectural experience of ‘Cleansing’ for the wellbeing of the mining community in Potosi, Bolivia. The city of Potosi as a model of the mining economy was established around the activities of miner’s daily routine. The whole lifestyle of Potosi still sitting on a highly dusty and dipolar way of living. During the era of diminishing ore in the silver mountain Cerro Rico, the modern lifestyle has reached a point of unsustainable balance. The scarcity of water and economic resource resulted in a shortage of sanitary facilities.Miners comfort the side effect of breathing in mining dirt by establishing in cave religion (El Tio) and Coca leaves chewing. The lacking buffer zone before they go straight back into family life intrigues more family conflict and crime. The Architecture will crawl over the steep slope in between the city boundary and mining entrance to become the new community center and attraction point for miners and their families. The Cleansing experience is designed for both physical and spiritual transformation.

Water crisis caused by the mine Polluted Water

Potosí lies near the headwaters of a major Bolivian watershed, the Rio Pilcomayo which flows from central Bolivia east to Argentina. Water resources in and around the city of Potosí have been dramatically and continuously impacted geomorphologically, geochemically, and ecologically by human activities since the initiation of mining. Potosí’s city limits, Hudson-Edwards et al. (2001) found dissolved metals concentrations orders of magnitude above background levels. Miller et al. (2002 and 2004) documented severe contamination of water and sediments up to 200 km downstream of Cerro Rico. Bolivian water quality standards are stringent, progressive, and comparable with those of most industrial nations.

Mining and ore processing are considerable contributors to water quality degradation downstream of the Cerro Rico mines. Streams and rivers that receive AMD, tailings discharges and runoff from mining areas or tailings deposits, or impacted tributaries that do so, contain concentrations of ecotoxic metals (As, Cd, Co, Pb, and Zn) that render them unusable and environmental hazards. However, the weathering of tailings within the bed of Rio Tarapaya appears to present a strong enough signal to override some of the effects of the natural attenuation that occurs in its tributaries.

Potosi, Cleansing Object

A.Physical Construct 1.01 Experimenting the model inside xxx.

Hypothesis The Cleansing experience is a journey of purification and bonding. The cozy bathing will intersperse with religious pilgrimage, taking the full advantage of the steep slope. The architecture will incorporate functions of dust sheltering and water recollection, to reduce resource waste and long term ecological use. The innovative construction method of earth casting and superficial foundation will prevent the construct from contaminating underground water and minimize the influence on existing natural conditions. The architecture is acting as an interface in-between the miner’s fatal working environment and normal city life, also as a long term junction to reconnect the mining communities including family members by introducing bathing related gathering spaces for a variety of social units.

Design Abstract The Architecture Object of Cleansing: [Designing the experience for changing the hygenic lifestyle in Potosi]

Thesis The project aims to use the Vaulting intelligence and Earth Casting technique to create the architectural experience of ‘Cleansing’ for the wellbeing of the mining community in Potosi, Bolivia. The city of Potosi as a model of the mining economy was established around the activities of miner’s daily routine. The whole lifestyle of Potosi still sitting on a highly dusty and dipolar way of living. During the era of diminishing ore in the silver mountain Cerro Rico, the modern lifestyle has reached a point of unsustainable balance. The scarcity of water and economic resource resulted in a shortage of sanitary facilities.Miners comfort the side effect of breathing in mining dirt by establishing in cave religion (El Tio) and Coca leaves chewing. The lacking buffer zone before they go straight back into family life intrigues more family conflict and crime. The Architecture will crawl over the steep slope in between the city boundary and mining entrance to become the new community center and attraction point for miners and their families. The Cleansing experience is designed for both physical and spiritual transformation.

Hypothesis The Cleansing experience is a journey of purification and bonding. The cozy bathing will intersperse with religious pilgrimage, taking the full advantage of the steep slope. The architecture will incorporate functions of dust sheltering and water recollection, to reduce resource waste and long term ecological use. The innovative construction method of earth casting and superficial foundation will prevent the construct from contaminating underground water and minimize the influence on existing natural conditions. The architecture is acting as an interface in-between the miner’s fatal working environment and normal city life, also as a long term junction to reconnect the mining communities including family members by introducing bathing related gathering spaces for a variety of social units.

Methodology The design developed from Environmental and Structural experimentations around two main elements: vault and pool. The Vault uses a hanging chain model reference to Antonio Gaudi, was tested by asymmetrical weighting strategies to meet the complexity of site topography. With technical study it was developed into a digital simulation system, corresponding with two main materialization strategies: self-supporting metal panels and vernacular construct. The ground condition is rich by earth casted pool typology, which designed to be cast into the sloped and cantilevered by self-supporting structure. Sitting in the context of Bolivian culture and fashion, the architecture is inheriting their enhancement of head character though exterior ventilation design on the roof. Hierarchy is expressed though the exterior design and curated height of space.

Criteria The architecture shall have the ability to hold a minimum of 1500 miners and their related family members. The minimum is the population within 10 minutes walk, while the architecture has much more attractive than that.

The vault shall focus on meeting different size constraint of the pool, and provides circulation indication for people. The majority of the space will use natural light though vault openings, And the sustainable use of the bathing facilities shall be beneficial for the next generations after the mine resources are exhausted.

Design output The site is not neighborhood specific, but mine- city relationship-specific. As a curated public facilit y, the major construct of vault and pool can be adapted to any other site with a variet y of topography and similar relationship. The ‘Cleansing Object ’ aims to be uniquely innovative a bathing typology for all around the world.

Interface The project start to explore the possiblities that can happen as an interface that communicate architecture potential and mining hygenic condition.

Through out 9 different physcial construct, the models and drawing is evaluated not in a chronological order but though interest discovering, and highlighting important directions to move forward.

Exploration Interface

The Architecture Object of Cleansing: Designing the experience for changing the hygenic lifestyle in Potosi

Physical Construct 1

[Water Holder & Topography]

The first model is using ready made pieces with exsisted topography and melted glass wax that flows over its surface. The model developed the interest towards an initial understanding about water that can be hold within a curated landscape.The drawing trying to reconstruct the physcial construct in a rationalized form, and sort out information that can help the construct to move forward. In this drawing , the in between space betweenthe topograohy landscape and possible forms of canopy is investigated in the next physical construct.

PC1 Drawing

[3d Scan & Reconstruct]

Physical Construct 2

PC2 Drawing

[Flow & Canopy]

The early stage of the physical construct brings out the interest towards possible form that holds water , the flow of water and the space in between a centered canopy.

Vacum forming and the technique of flexible joins remain as two impotant element being developed in later stage form finding pratices.

The form of the physcial construct is explored through grasshopper scripes.

Transparency under illumination

Side View canopy

Details

Grasshopper scripted is used to construct some digital tests on the page, delivers the interest of water holder have certain parameters to be controlled.

The Digital modeling and the realife assemble is the new investigation through this physcial cosntruct. The real model uses flexible joints to assemble, therefore the form is somehow lack of integrity. However, the 3d scaned model shows the space below the structures have the potential to be regonized as the element of canopy that actively reacts to the curated topograohy below.

[The assemblity between water holder parts]

Physical Construct 3

[Semi open space over the landscape]

The physcial construct is a diagramatic model that intened to make a enclosure out of a lanscape object.

The architecture element shall be blend into the landspace, with two main ways: permanenet enclosed structure and semi open structure that hangs in between the permanent ones.

PC3 Detail

Physical Construct 4

[Tensile Strcture]

In this model the topograhy become a testing field , which the intervals have been rationalised into slope of 5m in scale Tensile structure is injected into the cnc form and connected as a continous canopy. The tensile is not as an element that exsit as a design interets, but more of a form finding interest.

PC4 Detail

Physical Construct 5

[The Vault]

The model extract the interest of a rationalised landscape from the last PC, and trying to arrange a lanscapce with different steepness in terms of 3d slopes. A Dome structure is construted as framework, holding some tention fabric inbetween the gaps.The physical construct section shows less inhabitation possibility inbetween the vault and the slope, therefore the form of the vault have to be redesigned and investigate new potentials.

PC5 Drawing

[Steepness & Stiffness]

PC5 Drawing II

[Vault , Pool & Interface]

Physical Constructs Conclusion

PC1 [Water Holder & Topography]

[Highlights]

PC2

PC3

PC4

[Flow & Canopy]

[Semi open space over the landscape]

[Tensile Strcture]

PC5 [The Vault]

Interface Exploded Drawing

The Concept of creating an Interface is settled and crystalised into the interface prototype, which explain the main element that will be the following design focus [Interface as a Cleansing Object] to help the local hygenic crisis and establish unique architectural experience.

Design interest, extracted from previous generations of physical construct, have concluded two essential element [Vault] & [Pool], with the relationship of rather individually developed and assembled in a way thay allows enclosure to be formed and crawl over different .

Physical Constructs Elements

[Highlights]

Vault Element II

Vault Element I

How does the coffer compressed into the

How is the roof being designed according

shape of the roof?

to load bearing?

[Coffer]

[Roof]

Pool Element II [Boundary]

How is the boundary of the pools being retained?

Pool Element I [Topography]

How is the height of pool critical to the lifestyle?

Physical Construct Vault Element I [Roof]

non modular support and tension non modular support and tension

Physical Construct Vault Element II [Coffer]

expanding structural support

Physical Construct Pool Element I [Topography]

enclosed landscape

Physical Construct Pool Element II [Boundary of pool]

a continuity in self defining space boundary.

Hygenic Crisis and Cities Pre-Site Research

The Architecture Object of Cleansing: Designing the experience for changing the hygenic lifestyle in Potosi

Mirny, Russia

Copper nickel mining,

Extreme surface mining and high wall mining, extreme danger in urban life, rainwater aggregates.

Clean Waterbody , Contaminated landscape, Conflict between benefit of local life and the mining site.

The diamond-bearing deposits were discovered on June 13, 1955.

The development of the mine started in 1957, in extremely harsh climate conditions. Seven months of winter per year froze the ground, making it hard to mine. During the brief summer months, the ground turned to slush. Buildings had to be raised on piles, so that they would not sink from their warmth melting the permafrost. Production was stopped in 2004, and the mine was permanently closed in 2011, due to reduced recovery and the costs of working in the far northern climateThe town is served by the Mirny Airport. Safety concerns have been raised about aircraft operations near to the open diamond mine; helicopters are forbidden to pass over the abandoned workings.

Ely is home to a few thousand people, a place of long, hard winters that is, in the words of one resident, “not on the road to anywhere — we’re literally the end of the road.” People do not end up here by accident. For most of the town’s history, the main reason they came was to make a living off the rocks. The ore supported abundant mining jobs for generations.People have been coming to this area for another reason, too: to visit America’s most popular national wilderness area, the Boundary Waters Canoe Area, which encompasses roughly a million protected acres and thousands of lakes.just southeast of Ely, an international mining conglomerate has invested hundreds of millions of dollars during the past decade toward potential copper-nickel mines a few miles outside the Boundary Waters.But there’s a generations-long rift in Ely — between those who believe minerals are the region’s greatest asset and those who believe clean waters are — that has been laid bare recently.

Berkeley pit butte, Montana, USA

Thomton Quarry, Chicago, USA

Yuba River Goldfield , California, USA

Different contaminated water body: tailing pond and rain water aggregate, close distance to high dense city

Alternative water use, Adation to city planning of chicago

Dynamic water body: river, blackflow of storm water, Alternative digging: water ravine, Co-living with agriculture site.

5 City Investigation

[Post or ongoing mining?]

In the investigation , the selection of 5 cities that was seriously influenced by both water crisis and mining activites is hover between post and ongoing mining site. The project as a inteface and bufferzone to resolve some problem that can be improved by providing architectural experience, shall be benefit for already destoried landscape or for cities that still have potentials?

The pit and its water present a serious environmental problem because the water, with dissolved oxygen, allows pyrite and sulfide minerals in the ore and wall rocks to decay, releasing acid. When the pit water level eventually reaches the natural water table, estimated to occur by around 2020, the pit water will reverse flow back into surrounding groundwater, polluting Silver Bow Creek, which is the headwaters of Clark Fork of the Columbia River.The acidic water in the pit carries a heavy load of dissolved heavy metals. The pit’s water contains so much metal that at one point one of its owners, Montana Resources, mined copper directly from the water.The first plans for solving the groundwater problem were devised in the 1990s. Water flowing into the pit has been diverted by the Horseshoe Bend Water Treatment Plant to slow the rise of the water level. Ground broke on a water treatment facility in September 2018, with the goal to have the facility fully operational five years before the pit’s water level rises high enough to contaminate the groundwater of Butte. The Berkeley Pit is currently one of the largest Superfund sites.Two communities and much of Butte’s previously crowded east side were consumed by land purchases to expand the pit.The Anaconda Company bought the homes, businesses and schools of the working-class communities of Meaderville, East Butte, and McQueen, east of the pit site. Many of these homes were either destroyed, buried, or moved to the southern end of Butte. Residents were compensated at market value for their acquired property.

The Berkeley Pit is currently a tourist attraction, with an adjacent gift shop.

A quarry is a type of open-pit mine in which dimension stone, rock, construction aggregate, riprap, sand, gravel, or slate is excavated from the ground.Thornton Quarry is one of the largest aggregate quarries in the world, located in Thornton, Illinois just south of Chicago. As part of the Chicago Deep Tunnel project, both Thornton Quarry and McCook Quarry will serve as reservoirs to reduce the backflow of stormwater and sewage from Chicago area rivers into Lake Michigan

The Yuba Goldfields, also known as the Hammonton dredge field, is the largest gold dredge field in California.

The goldfields are noted for their otherworldly appearance (a result of gold dredging operations), filled with roughly linear mounds of gravels (called dredge tailing windrows), ravines, streams and turquoise-colored pools of water. From the air, the goldfields are said to resemble intestines.

Marysville was home to a significant Chinese American community in the 1860s, but it violently drove all its Chinese American residents out of town in February 1886.[10] The Chinese American population has not recovered sinceThere was also an active Jewish merchant community in Marysville from the Gold Rush era through the early years of the twentieth century. During the Gold Rush, the ranch became a stopping point for the riverboats from Sacramento and San Francisco that brought prospectors to the digging grounds.

2 City Comparison

2 City Comparison

[the site selection]

Gällivare, Sweden

Potosi, Bolivia

[the site selection]

2 City Comparison

2 City Comparison

[General Local information comparison]

[General Local information comparison]

City Condition

Mining Project Boliden Aitik Gällivare, Sweden

Cerro rico Project Potosi, Bolivia

Climate

Climate Over Year More Extreme Temperature difference

Population

Altitude

8449

Climate Over Year More MildTemperature difference

174,973

Estbalished Time 700m

2017

4090 Type of Mining

Operation

People

1968

Surface Mining

Boliden

Underground Mining

Silver

Distance From the City

17.5km 16mins Drive

Span of the Mine

Over 50years

Over 50years

700

300

Number of Employee

29km 20mins Drive

Site The site is not limited by conditions that suits the potential interest of the project , but a urban population with more urgent issue with the hygenic crisis will be more of a importance to research, as a possible sustainble strategies for future other sites rather than problem solving.

Site

The Architecture Object of Cleansing: Designing the experience for changing the hygenic lifestyle in Potosi

Potosi,Bolivia

Potosi,Bolivia

City Texture

generic view

Major Mining Entrance area

Residence 125 entrance 12000 Miners

Potosi City Plan

[the division between mine and urban life]

Site surrounding Plan

[mining related facilities and mapping]

Site boundary analysis

[Building typology arround the site]

Topography Drawing of Site

[Building typology arround the site]

Site boundary analysis

[Building typology arround the site]

LifeStyle Drawing [Water related miner communities daily]

Pool Pool is the literal holder for the activities of bathing, but needs more design strategies on the arrangement and interlocking system to proceed a variety of requirement. The social units including family, different age group is pointing towards different height and deepness of the pool.

Design Body I Pool

The Architecture Object of Cleansing: Designing the experience for changing the hygenic lifestyle in Potosi

Earth Casting Technique-Paolo Soleri Referencing to a manual construct of earth casting

Earth Casting technique is a way to retain the pool without paneling and accurate geometry calculation. It is constructed by excavating the landscape soil into a negative shape, and spray short-crete into the hole. the soil will absorb water to make the curing faster. take away extra liquid will leave a thin layer on the surface, which can be lifted up from the site as a pool.

A.Design Element - Arches

The earth casted element is to celebrate the pool can be constructed in a way to be structural entrances .

I. Earth Casted Sand Mixture

II. Sand and Gardening Soil

Elevation 1:25

III. Adding some water for moisture

IV. Compression formwork

The model is casted in the order of first injecting the structural support into the ground and cast the supporting columns, and then after 2o mins when the support is fixed, then dig a desidered version of the pool.

A.Design Element - Arches

The earth casted element is to celebrate the pool can be constructed in a way to be structural entrances .

I. Compression finished

II.First layer evacuation

Elevation 1:25

III. Cast the first layer into solid

IV. First layer cured before second layer evacuation

The model is casted in the order of first injecting the structural support into the ground and cast the supporting columns, and then after 2o mins when the support is fixed, then dig a desidered version of the pool.

A.Design Element - Arches

The earth casted element is to celebrate the pool can be constructed in a way to be structural entrances .

I.Wood frame inserted

II.Compression formwork

Elevation 1:25

III. Pour plaster and remove extra liquid

IV. Lift the element with the wood sticks

The model is casted in the order of first injecting the structural support into the ground and cast the supporting columns, and then after 2o mins when the support is fixed, then dig a desidered version of the pool.

A.Design Element - Arches

The earth casted element is to celebrate the pool can be constructed in a way to be structural entrances .

I.Wood frame inserted

II.Compression formwork

Elevation 1:25

III. Pour plaster and remove extra liquid

IV. Lift the element with the wood sticks

The model is casted in the order of first injecting the structural support into the ground and cast the supporting columns, and then after 2o mins when the support is fixed, then dig a desidered version of the pool.

Thermal sustainable strategies

Design Element evaluation

Physical Construct Cleansing Object I

Typologies of Pool

Testing the possibilities of interlocking pools into a scaled space

Planofenclosureformwork

Pool typology I Injectedformwork+Externalsupport

possibleplatform

Pool I - Locking into Pool II

Pool typology II Subpool+Seldsupport

PoolII-Selfsupporting

Pool typology III Injected formwork +Arch

Physical Construct Cleansing Object I

The Experience of Cleansing

Vault Vault is playing the role of recycling water and create most part of the enclosure for the bathing related facilities. The support of the vault needs to incorporate the geological condition which is higly tilted and steep. Traditinal vault will not satisfy the scople of the project , which wish the facility can spread on the boundary of the city in between the mine.

Design Body II Vault

The Architecture Object of Cleansing: Designing the experience for changing the hygenic lifestyle in Potosi

Load Bearing Vault

Vault Deformation test prototype

Asymetrical , Load bearing, joint

What will alter the load bearing performance of a vault?

Digital simulation and materialization

During the develpopment of science, there are ways to simulate and exame possible strategies to transforming a catenary model into a materialized form. In this chapter, simulaiton will be evaluated and compared to inform possible strategies for constructing the vault.

Spatial Test start from plan

In modern force membrane or vault simulation software, the data given by the parameters are often not fully applicable to real life.

But the quaility of virtual is helpful to resolve some difficult form finding target with more freedom.

Center of gravity The center of gravity for the catenary is decided on how much weight is puted on to the catenary. For one modelthe center of gravity can be shift in Y direction but as long as the symmetrical behavior is maintained, the center of gravity will not go offline.

Gaudi ‘s Hanging Chain Model for the simulation of cantenary form finding.

Catenary as an intellenge base on the invention of hooke;s law, have the quality of lifte adjustablity and infinite possibility to alter the physical model with hand. The vault and pool both sits on highly topographical condition in potosi, however needs completely different strategies to land. The vault needs to touch the soil as less as possible to avoid interupting activities inside, and also have to be anti slipery ain terms of individual foundation.

A prototype before a more delicate model of catenary, testing a mobility of a frame and how much it can influence the chain below. In evaluation, the catenary model shall be multi -stories, being able to shift in X and Y direction, and also can have long beams to hold stable in order for further observation.

Deformation Practise Acts Through 3 series actions for texting out the deformation output of the cantenary.

Stretching

By stratching the frame towards 3 degree of demoration: 90, 45 ,27.5degree slowly, the deformation will influence the chain from both front & side view.

90° 45° 27.5°

Tilting

The catenary is tilted by adding extra height supporter from on side , applying the tilt angle of 30 and 20 degree towards the front view of the catenary.

20° 30°

Sliding

When the catenary is distorted in certain way, some previous joint for holding the load is no longer working. Sliding the position where the load is touching the frome is the main adjustmement method for understanding how the deformation work.

0-12.5mm

Axis of a Deformation I- Horizontal

Perspective plan of a defromed vault A.Physical Construct 1.01 Through analysing the perspective plan, the arragnement of landing point will be simulated into digital version.

Experimenting the model inside xxx.

Axis of a Deformation II- Vertical

Axis of a Deformation II- Artificial

A.Physical Construct 1.01

A.Physical Construct 1.01

Experimenting the model inside xxx.

Experimenting the model inside xxx.

A.Physical Construct 1.01 Experimenting the model inside xxx.

A.Physical Construct 1.01

A.Physical Construct 1.01

Experimenting the model inside xxx.

Experimenting the model inside xxx.

A.Physical Construct 1.01 Experimenting the model inside xxx.

Assembly pattern Stripe Strategies Kangroo is still a crucial tool to simulate a mesh surface that follows catenary behaviour. The simulation is not following a material consideration of the geometry, the simulation can expand to a height that needs either using extra structural support or a strong holding force for the structure. In the past parametric projects, joint needs connect to all surrounding panels, which is enlarging workload and time cost for fabricating any geometry like this.

Unlike other projects they did, in this project they combine a simulation between a catenary behaviour and a tentile membrane behaviour. The final geometry is coming from inflating a tree branch like initial mesh. The mesh UV curves is responsible for deform under the stress,but the lenghth of stretch is usually needs to less than the length of the initial curve. However, the studio is setting the spring length larger than original uv curve lengh, making the geomrtry more blowed up. In major Frei otto's architecture, there is a primary struture to apply force to tensile membranes , but in Marc Fornes Project, they extract a logic of stripes and digard a component by component assembly.

Stripe patterns are widely spread in nature in different scales, from the smallest molecules to skin pattern of plants and animals.

The generation and the properties of such structures are explored through parametric techniques using algorithms to create complex hyperbolic geometries.

Strip surface discretization can be used to represent three-dimensional objects defining space, form, and structure simultaneously. They are intensively adopted in various fields of construction, like boat industry, concrete formworks, panelling techniques among many others.

On the local level, based on the ring like typology and its active-bending principle, the resulted structure acquired strong self-supporting capacity increased by the double curvature within the global shape. A self-standing lightweight rigid structure needs to be build with proper material , that either carries a property of bendable, or hygroscopic.

ETS Conclusion A.Physical 1.01 a range of catenaryConstruct behaviour followed typology

Environmental focus 1.01 A.Physical Construct

Experimenting the model inside xxx.

Experimenting the model inside xxx.

Referencing tahjin’s water circulation strategies

Environmental focus 1.01 A.Physical Construct

A.Physical Construct 1.01

Experimenting the model inside xxx.

Experimenting the model inside xxx.

thermal performance target of the design

Experience The lifestyle before being cleansing is bearable, but not sustainable for both life expectancy of potosi residence, or for the mine activities it self. The project wants to contruct the experience that bathing becomes the media to release the tention of surviving in mine, and the sense of both sharing and privacy exsist in the washing actities. Although the whole city had not reached the sanitation level of a urban city, the scope is to starth with the interface with just bathing, then expanding in to all kinds of living such as restaurant and working space, bringing the modernity into the city by not destorying any exsiting ritual or culture, but by providing a clean belonging place for mining communities.

Design Body III Experience

The Architecture Object of Cleansing: Designing the experience for changing the hygenic lifestyle in Potosi

Spaces

Original Sketch

Curational Pilgrimage Original Sketch

Sectional Logic Original Sketch

Original Liftstyle on slope Liftstyle drawing

Initial Massing Exploration

Massing Orientation development

Planar exploration on the slope

Arranging through zigzag stairs

Pool planar orientation development A oriented swarm organization

Planar organization

Local Building Element

Potosi local construction

Bolivia local building translated into architectural application

Referencing local elements to architectural applivation of religous space fom meshing modeling

Moment I

Entrance

Moment II

Bathing Communal Space

Moment II

View Platform

Moment IV

Chapel

Moment V

Resting & Exit