Introducing Salt Water Intrusion

In 2012, India’s first Aquifer Atlas was released by the Central Ground Water Board. It served to confirm pre-existing studies showing that over-exploitation of groundwater resources had resulted in saline intrusion in many parts of Chennai city, rending ground water salty and unusable. According to the ‘Aquifer Vulnerable Map’ prepared as a part of the atlas, Chennai was classified as ‘Over-Exploited’, but was interestingly among only four places in the State of Tamil Nadu that were classified as such.

In 2007, the Public Words Department had demonstrated that sea water had contaminated aquifers as far as 15 kilometers away from the coast.  This was a cause for concern because aquifers were interlinked and that pollutants could potentially travel from one to another. Unsurprisingly, the focus of studies recently shifted to South Chennai. However, this was also attributed to rapid increase in water demand in those areas due to rapid urban expansion. On the whole, the Chennai dsistrict was marked as having Nitrate levels higher than the permissible limit of 45 mg/L.

Anonymous sources said that a major reason for such sea water intrusion was repeated violations of rules relating to restrictions placed on tube wells in coastal areas referred to as Coastal Regulation Zones (CRZ). Further, they questioned whether or not people were punished for violating these regulations.

This article presents a general picture of salt water intrusion in Chennai. It is one of the two major issues that has been resolved by rainwater harvesting, with the other one being water scarcity.

Source:

Yamunan, Sruthisagar. “Sea Water Intrusion a Big Challenge for City Aquifers.” The New Indian Express, October 8, 2012.

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Pitfalls of Decentralization

The conceptualization of decentralization in developing countries as practice of good governance is well-entrenched in today’s international development framework. Decentralization represents the shift of power away from centralized authority under the state to local and regionally based entities. Among other things, it emphasizes a greater role for the market and as well as participatory governance. The World Bank’s emphasis on good governance as well as funding from entities such as the MacArthur and Ford Foundations has helped enhance the popularity of the idea.

However, according to this article, the goals, aspirations and processes of decentralization are threatened and are at risk of being sidelined given the increasing prominence of Globalization and its associated processes, of which decentralization is ironically a part.

 

The process of local administration in India is represented by locally elected bodies known as Panchayats that are engaged in use of local knowledge and participation. However, such bodies are linked to higher levels of administration where the policy and planning process is essentially technocratic, resulting in a condition where the linkages between these levels are not well defined.

Sometimes, technocratic polities that make sense at higher levels of administration turn out to be detrimental to local interests. For example, liberalization of agricultural products in India has induced a fall in prices of produce, resulting in increased farmer suicides. On the same lines, the venturing of multinational corporations into the domain of large-scale agribusiness has threatened the livelihoods of many farmers, without any promise of alternative employment. In essence, a framework at a higher level of administration that does not have local empowerment as a focus defeats the purpose of decentralization itself.

This article is relevant to my thesis topic primarily because of the preeminent position of decentralization as an explanation for ‘success’. In recent times, a large number of public sector projects have seen power decentralization, either through the involvement of the private sector, or through scaling down the size of the intended project to a level that can be managed locally and then implementing it in multiple locations. The Rainwater Harvesting project in Chennai is no exception. However, since this article argues against this very premise, it encourages me to search for the roots of the successful outcome in a more rigorous manner.

Source: RoyChowdhury, Supriya. “Globalisation and Decentralisation.” The Hindu, January 05, 2002.

 

 

Centralization vs Decentralization: Part I

Water supply has traditionally been within the domain of centralized management. Such centralization has led to the construction of large-scale pipeline systems as well as sourcing of water from distant areas, at the cost of abandoning local water resources. However, concerns relating to increasing water demand in major urban centers, environmental degradation at the sources of water as well as the financial cost of bringing water from distant areas have led to a shift towards decentralization of water supply and localization of water sources, both in developed and developing countries. Such a shift is also in line with the idea of urban sustainability where local solutions and the participation of local governments and citizenry are deemed valuable.

             Some decentralized approaches to water management include Storm Water Management, Wastewater Management, rainwater Harvesting and Grey Water Reuse. Stormwater management relates to the harvesting of urban surface runoff from rainfall resulting from impermeability of such surfaces. Methods widely used include micro-scale solutions such as ponds, wetland development, permeable pavements and other infiltration techniques. Wastewater management includes harvesting of water with ‘colors’, including blackwater, greywater and yellowwater. In this case, such flows are mixed and treated in wastewater treatment plans, and are subsequently returned to water bodies with the addition of certain nutrients that are lost in the process. Even though wastewater treatment is general a part of a centralized system, it is possible to separate and treat them at the source.

                       Rooftop  rainwater harvesting, another decentralized mechanism is easier in that water is collected at source before mixture with groundwater and that no kind of special treatment is required. Additionally, establishing micro-scale systems of rainwater harvesting at the level of the household is easy. However, the system does have drawbacks. One, is this idea is that rainfall over the long term is generally variable and that it is impossible to predict reliable availabilities. Another drawback is the fact that there might still be a degree of mixture with contaminants such as atmospheric pollutants and bird and animal excreta on the roof. Finally, Greywater reuse refers to use of wastewater that does not contain any kind of excreta, and in general, has a low microbial concentration when compared to mixed wastewater. This water is used for the purposes of urban agriculture and gardening.

Domenech, Laia. “Rethinking water management: From centralized to decentralized water supply and sanitation models.” Documents d’Analisi Geografica 57, no. 2 (2011): 293-310.

Wind Forces in a Tornado-like Vortex

Sabareesh Geetha, Rajasekharan, Matsui Masahiro, and Tamura Yukio. “Characteristics Of Internal Pressures And Net Local Roof Wind Forces On A Building Exposed To A Tornado-Like Vortex.” Journal Of Wind Engineering & Industrial Aerodynamics 112.(n.d.): 52-57. ScienceDirect. Web. 16 Oct. 2013. DOI: 10.1016/j.jweia.2012.11.005.

From this article in the Journal of Wind Engineering & Industrial Aerodynamics, I was able to learn about the types of forces a building is subjected to in a tornado. The investigation modeled buildings with different percentages of openings on walls and roofs. Then the study tested the models in a tornado simulator under conditions of an EF5 tornado, which means wind speeds are 200+ mph. Using multipe pressure sensors inside and on the model’s exterior, data was collected and the results compared. The study found that the pressure on the roof varied based on the buildings proximity to the core of the tornado. It also identified uplift as the dominant load condition near the tornado’s core, and radial loading as the dominant condition further from the tornado’s core. Because a tornado moves, any product that I design will have to address both radial loading, which induces bending stress, and uplift, which induces axial tension.

Because the study used a scaled down model, the tornado had to correspond to the same scale. The scale used was 1:1000. However, I do not intend to design/model a full house. I would like to take a chunk of a house where the wall meets the roof and  test how well they hold together. With more investigation, I can find the wind pressure’s force and use those numbers to apply load to my designs, rather than test only for scaled down loads. It would also be of some benefit to test single elements under tension and bending; rather than a chunk of a house, I could try to pull two pieces apart. I will still have to look into the equipment available to me for testing procedures.

Buildings of the Future May Be Designed Autonomously by Algorithms

digitalgrotesque

Buildings of the Future May Be Designed Autonomously by Algorithms

Digital fabrication, the act of creating a form in digital space and replicating physical prototypes via 3D-Printing, is a field coming rapidly into focus in the industry of architectural design.  Digital mediums allow us to create shapes and forms that would otherwise be impossible to generate from simple hand drawings or modeling exercises, creating interesting forms that are wholly new in our human history.

A team of Swiss architects, led by Michael Hansmeyer and Benjamin Dillenburger, have taken this concept of digital fabrication to the next level and are essentially attempting to remove the human from the design process.  Their work incorporates mathematical algorithms, basic parametric equations, and a few curious biological processes to allow the computer to freely design within a generalized set of constraints (making sure that doors function as doors, windows as windows, columns as columns, etc.).

The results, dubbed “Digital Grotesque’ show a very elaborate design that, upon first glance, appears to be a cross-breed of architecture and a cell undergoing mitosis.  The symmetry, being generated purely analytically in the brain of the computer, is flawless, some might say to a fault.  While the forms generated are quite elaborate and interesting, there is a certain appeal that is lost in the perfection of the forms.  One does not feel that there was much, if any, human influence in the design choices illustrated by the computer.

Similar breeds of biological and digital mediums have been illustrated through MIT’s Media Lab and the work of their Mediated Matter team.  One such project involved the unification of a robotic arm used to navigate string around metal frames with pegs along the perimeter, and 6,500 silkworms.  After studying the forms generated naturally by the silkworms, the team set out to create a frame work that would allow the silkworms to “fill in the gaps.”  The result is the Silk Pavilion, an interesting (and more natural feeling) sculpture that shows how biological phenomena and digital fabrication can work together to create stunning new forms.

While creating a physical machine large enough to freely print a single-family home in its entirety is a bit outside the realms of feasibility at this point, there are numerous ways that digital fabricators are stretching their equipment to meet the very real need of rapidly producable and deployable housing.  From monolithic robotic arms, to swarms of droid makerbots, to animal slave labor,  the digital fabricators of our age are pushing the boundaries of the new medium to bring rapid prototyping to every industrial field with Architecture leading the charge.

Integral Attachment Theory – Designing Plastic Parts

“Design Solutions Guide.” BASF Corporation, Engineering Plastics. 2007. Web. 23 September 2013. http://www2.basf.us//PLASTICSWEB/displayanyfile?id=0901a5e1801499d2

“Technical Expertise: Snap-Fit Design Manual.” BASF Corporation, Engineering Plastics. 2007. Web. 23 September 2013. http://www2.basf.us//PLASTICSWEB/displayanyfile?id=0901a5e1801499d5

I first encountered this guide over the past summer working on a UROP with Larry Sass. We were asked to develop a connection detail that could work throughout the house we were fabricating. One of my colleagues had used some of the images as inspiration for our project, though we didn’t get into the material of the guides. I’ve spent the last two weeks reading through the sections and scanning the tables. There is a lot of information in these guides!

The most useful information in these guides are the structural equations that need to be considered when designing your part’s geometry. I was happy to see that much of the structural considerations were topics that I am already familiar with and comfortable calculating, such as stress, strain, moments, and torque. Also really useful are the tables included that list the equations needed to calculate moments and certain constants by sectional properties. Furthermore, the guides include classification and physical properties of plastic materials. This will be very handy in choosing the appropriate grade of plastic in developing a connection design. Properties such as loading capacity, thermal expansion, moisture absorption, and impact resistance will directly affect my decisions.

The second guide focuses on snap-fit design. Snap-fit, or press-fit, uses force to connect one part to another through some slot (see image). I’ve touched on this a bit in an earlier post. Initially, I assumed this is the form my connection detail would adopt, but from the first guide I now have new ideas for ways that two parts can connect. They can screw into each other. I also wonder whether material expansion can be exploited in design: can one piece be a mold for the following piece, yet the mold doesn’t allow the second part to be extracted?

While there is a lot of useful information in these guides, I’m left with more questions. The examples used in the guides are small parts; aspirin bottles/caps, car door handles, tool handles, etc. The forces they assume are also very small. I wonder if these same principles can be applied to pieces 2 to 3 times larger and under hundreds of times more force! I will have to find examples of more similar use parts, maybe airplane manufacturers have used plastic. That could be interesting…

snap-fit

Methods for Artistic Stylization in 3D Animation

In his thesis, Schmid explores new methods for tools that would give artists greater flexibility over the visual style of their computer animations. He studies stroke based rendering and develops two ways brush stroke rendering, specifically the brush stamping technique commonly used in image editors like Photoshop, can be applied to 3D digital renderings. His first method takes time and space into account to produce high quality images while his second takes hardware speed and capability into account to achieve high interactive rendering performance. These two methods both solve the problem of the depth order and occurrence order of paint strokes. His thesis develops not only only how to generate the 3D canvas that would hold the models, but also how to apply standard rigging tools and apply traditional 3D rendering processes (surface shaders, ray tracing etc).

Schmid defines a brush model as strokes represented by a geometric curve that would in essence act as the centerline of the stroke. From this skeleton curve, a procedural shader or ribbon texture recreates the appearance of a brush stroke. For the 2D platform, the representation of a brush stroke is brush stamping, in which a single brush texture is repeatedly blended along a curve.

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The challenges of this technique in 3D, however, is difficult to represent as brush stamping does not capture how the shape and length of paint strokes change over time. Brush stamping also leads to aliasing problems (separated brush stamps causing lack of flow) that may lead to difficulties in rendering the 3D brush stroke. Combatting these issues, Schmid derives an algorithm that results in successful 3D representation results. When rendering brush stroke textures, transparency also plays a large role.

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Moving on from brush strokes is canvas texturing. Canvas texture may refer to the texture of paper and enhances elements, such as brush stamps, placed on the canvas. Canvas texture is fixed with respect to the origin. Because “splats”, which refers to the textured quads rendered on the screen, are not fixed, moving brush strokes in front of the textured canvas create a “shower door” effect, in which brush strokes seem to be seen through a distortion layer, like a water droplets on a shower door. Canvas texture enhances the stylistic element of rendered brush strokes.

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Schmid builds a 3D painting software system called OverCoat. By using a 3D canvas and his brush stroke techniques, paint strokes are embedded in space. Artists an create modeled proxy objects that define the overall layout of the scene. Geometric detailing is not required as strokes are embedded and the layout will not be rendered. OverCoat is based off mathematical optimization algorithms that I will not delve into as they are fairly complex and difficult to understand as well as explain. In addition to brush stroke rendering and canvas texturing, Schmid also includes various other tools that aid with animation and motion blurring. His software is demonstrated with rendered beautifully rendered 3D images that still retain stylistic brush strokes.

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Schmid hopes to continue to build on his work. While OverCoat successfully creates 3D paintings, it also requires much manual work done by the artist in lighting and texture information. In the future, he wants to develop his software so that stylized 3D paintings can exhibit and support view-dependent shape changes that are reliant on dynamic lighting.

Schmid, Johannes. Methods of Artistic Stylization in 3D Animation. Thesis. ETH Zurich, 2012. Web.