Thoughts on the Engineering Industry

A blog covering engineering, technology and business topics

Archive for the tag “design”

Four Basic Steps to Determine if your Shingle Roof Has Been Damaged by a Hail Storm

Hello everyone, I hope your weekend went well.  I went to see the new Bond movie with my brother Friday and last night I went to a west coast swing dancing class and social event.  Other than that, I’ve been doing my usual stuff like working out and my job inspecting buildings.  Today, I’ve decided to write a blog post explaining four basic steps to determine whether a composition shingle roof has been damaged by a hail storm and quantify the extent of damages.  I’ve avoided this topic for two reasons: one is that there is a lot of information out there about this already, and the second is that it takes some prior experience to make an accurate assessment.  However, it is one major component of my job and I feel like I can provide some practical information that will help you should you need it.

1) Look for spatter marks on surrounding surfaces (http://goo.gl/COQH3i)

Spatter marks serve as a indicator of the size and direction of the recent hail.  The size of the spatter can be compared to the impact marks elsewhere to determine the extent of recent damage.  The directionality can be determined as well by figuring out which directional faces have or do not have spatter.  In addition, spatter will fade over time – this can differentiate between different ages of spatter marks within a recent time period in most cases.

2) Look for impact marks at susceptible surfaces (http://goo.gl/m15Wmc)

Impact marks can also be observed on some metal and wood surfaces.  Air-conditioning units are a good indicator due to the fact that they have 4 sides and metal/coil fins that are either soft or oxidized.  Spatter can be observed as mentioned before, as well as indentations.  Furthermore, the indentations can be examined to check for soiling, oxidation, or other forms of staining to determine the relative age of the older indentations.

3) Look at the general condition of the roof (http://goo.gl/7p5Yul)

The general condition of the roof will also affect the extent of hail damage.  Examples of other things that damage shingles aside from hail are general weathering, mechanical scrapes, blistered asphalt, and raised nails.  A roof with a worse general condition will be more susceptible to damage and could reduce the compensation should you involve the insurance company, similar in practice to automobile insurance compensation.

4) Look for hail impact marks and examine their condition/quantity (http://goo.gl/2nguV8)

The last step is to look for hail impact marks on the shingles.  Sometimes a relative age can be determined by checking for weathering of the reinforcement or asphalt within the exposed asphalt/shingle reinforcement.  To quantify the extent of damage, you can count the number of recent and/or old hail impact marks, as well as other general conditions if desired, withing a 10′ x 10′ square.  This is referred to as a test square by engineers and inspectors in the roofing business and is helpful information when estimating the cost of various types of repairs.

These 4 steps are the basic process I use to determine the extent of damage to a shingle roof.  Does anyone else have experience in roof inspections?  If so, what would you add to this list as a basic procedure?  For homeowners, have you had to deal with an issue like this before and how was the experience?  If you enjoyed my post, hit the like button, follow my blog for updates and share this post with your friends.  Thanks for reading and have a good week!

Image source

http://goo.gl/1MbnTT

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Application of 3-D Printing and Modular Design to Construction

Hello everyone, I hope you guys had a good weekend.  Today I would like to discuss a couple innovations which apply 3-D printing and modular design innovations to construction practice.  These are applications that were more common in manufacturing and prototyping initially but can be applied to construction as well according to the article by Business Review Weekly.

The first innovation is the application of 3-D printing to the creation of moulds for precast concrete.  Traditionally, other materials such as wood, foam or rubber have been use, and constructing these moulds could take months to construct.  The Laing O’Rourke Company has developed a method that 3-D prints a large scale wax substrate mould at a rate of 150 kg/hr using a robots.  They have applied this to common projects such as stormwater pipes and have achieved cost savings of 50% to 90%.  Additionally, this solves the waste problem because the wax mould is lifted off or melted away in a water bath after the concrete is cured.  The wax can then be filtered and recycled.

The second innovation is the use of modular components in hospital construction.  Hospitals are one of the most expensive areas of infrastructure because they are individually designed.  Hickory Group has developed a modular panel for use in reception and administrative areas.  These areas use what is referred to as “accommodation components” which constitutes up to 40% of the construction cost of a hospital.  By using the modular panel, construction time can be cut by 40%.  Furthermore, the panels are easily replaceable.  If a panel is damaged, the hospital  can simply order a replacement and have their maintenance worker install the new panel.

Both of these are very good innovations in my opinion.  They are taking methods that have been proven effective in several previously tested applications and expanded their usage.  Furthermore, a reduction in time of construction and cost of maintenance/construction has been achieved.  I would be interested in seeing a more detailed account of the numbers and statistics.   However, based on the information provided, these are great examples of low risk/high reward solutions that can greatly improve construction practices.

What is your opinion on these innovations?  Do you think they’ll be effective?  If you enjoyed reading, like the post and share it with your friends.  Thanks for your time and have a good week!

Sources

Michael Bleby, “BRW Most Innovative Companies 2014: Why Construction Companies Are Thinking Like Manufacturers”, Business Review Weekly, October 9, 2014, http://goo.gl/O0oD6E

Image Source

Anne-Mette Manelius, “Concrete After Dark – Is There An Afterlife for Concrete?”, Concretely, October 17, 2014, http://goo.gl/IYI6q2

Benefits and Implementation of “Green” Urban Design

Hello everyone! I hope everything is going well.  This week I would like to talk about the incorporating “green” elements to city planning. I read an article a while ago that pointed out some interesting aspects of city life.  Most people who live in cities don’t notice nature around them in cities, instead they go on vacation to find nature.  Furthermore, more and more of the world’s population lives in cities.

This article listed the following benefits of the inclusion of nature into a city:

  • improved health and lifestyle
  • increased lifespan
  • reduced stress and aggression

Traditionally, the use of green space has been an aesthetic concern rather than a requirement for psychological health.  In addition to that, most urban planners haven’t claimed ownership of the issues related to lack greenery in the cities.  However, that is changing in Detroit, Europe and Singapore.  The researchers believe that greenery needs to be incorporated into urban planning from the ground up.

The article recommends that urban planners start incorporating the following elements to urban planning:

  • to consider the value of the greenery in an area before starting construction
  • to cluster homes and leave some easily accessible locations with greenery or natural elements around neighborhoods for city dwellers
  • to quantify the costs/benefits of different types of greenery and invest in them accordingly

While I think that some of the contributors come across as overzealous at moments, I agree with the concept.  Some of my most relaxing moments when I lived in Arlington, TX were the times I spent running at River Legacy Park.  It was a park that had a great section of in which I could loose myself in nature and reach a zen-type running state.  This article highlights benefits of incorporating nature that I have experienced myself.

What are your thoughts on incorporating nature into cities?  Do you agree with the articles assessment?  What would you do to incorporate nature into cities?  If you enjoyed the post, like it and share it with your friends.  Thank you for your time and have a good week!

Source

Anderson, Erin, “How Green Cities are Better for us Physically and Psychologically”, The Globe and Mail, July 5, 2014, http://goo.gl/PgM8Da

Benefits of Reusing Composite Shingles in Asphalt Roadway Construction

Hello everyone! I hope y’all have been doing well.  Today, I want to talk about an interesting innovation I read about the construction of O’Hare Airport. (http://goo.gl/WjI8Ek)  They collected used composite asphalt shingles and used them as part of the asphalt binder in the runway and various road type structures for the facility.  In this post, I will outline the process and the benefits.

 
The process:
Old Shingles Are Collected:
First, shingles are collected for reuse in the system.  At first, there weren’t any incentives added to motivate people to recycle used shingles.  However, some incentives have been created through different programs in various locations – all them outlined in the article.  One of them is a ban on sending large amounts of shingles to the landfill.  Another concept is an increased charge for disposing of shingles as compared to providing them for reuse.  The only exception is shingles that incorporate asbestos in their production and various limitations are discussed for reducing that risk.  Overall, the incentives seemed effective in my opinion.
 
Shingles are mixed into a pure asphalt binder:
The next step is that shingles are ground up and melted.  Once melted, this product can be added to the pure asphalt binder to increase the volume of this asphalt binder product.  At O’Hare airport, the shingles made up a 3% percent portion.  This didn’t make a huge dent in the budget but depending on the project it could reduce costs more.  Statistics and comparisons are provided in the article.
 
Asphalt is Laid Like Normal:
The asphalt binder and resulting asphalt is used like before.  As long as any differences in material properties are accounted for, the design and construction remains the same.  This results in an easy implementation on the construction and design side of the process.
 
The Benefits:
Reduced Use of Oil:
Oil is a precious commodity; anytime it’s usage is reduced, I consider it a good thing.  Along with that, it is easier to get a hold of used shingles than oil.  For both of these reasons, I consider the reduced oil usage a considerable benefit.
 
Reduced Cost:
The cost of using reused shingles is lower than using a pure asphalt binder.  Unless the scale is large, it is a minimal cost difference.  However, considering the scale of infrastructure cost these days and the amount of repairs needed, the scale is large enough that it would make a difference.
 
Reduced Waste:
These shingles, if not used in this capacity, would most likely be going to a landfill.  The lack of landfill space and shear quantity of human waste going to landfills is a current issue and reducing the amount from the housing would be a large contribution towards reducing that waste.
 
What is your opinion on the usage of this mixed asphalt binder?  Does it provide enough benefits to outweigh the cost and effort of changing the process?  Are there any noteworthy drawbacks or additional benefits not mentioned?  Thanks for your time and have a good week!
 
Sources:
Jon Hilkevitch, “Getting Around: Old Shingles Get New Life on O’Hare Runway”, Chicago Tribune News, June 30, 2014, http://goo.gl/WjI8Ek
 
Image Source:
“Why Homeowners Should Choose Asphalt Roofing Shingles Recycling”, Asphalt Roofing Shingles Recycling, October 18, 2012, http://goo.gl/u9l7cD

Benefits of BIM Modeling in Project Pricing for Head Contractors and Subcontractors

     Hello.  How is everyone doing?  Today I would like to discuss the statistical breakdown of the benefits in project pricing BIM modeling can provide for the head contractors and subcontractors involved in the design process.  BIM modeling is something that is collectively touted by most innovators in the building and infrastructure design/build field.  However, it would be helpful to understand who has the most motivation to implement improved BIM modeling.  As stated by David Mitchell, “For different types of projects the people you need to engage, changes. We need to acknowledge that the savings arising out of a building project differs significantly to those of a civil or resource project.  There also needs to be an appreciation of when a construction contract or subcontract is formed as well as the type of construction contract that has been entered into.”  Therefore, the issue is approached in regards to those factors.

For a commercial scale building project, the indirect cost such as design and overhead management amounts to 17% as compared to 83% for the construction costs.  In addition, the ratio of margins between subcontractors and contractors is 7 to 1.  Therefore, it benefits the subcontractors the most to apply the BIM modeling.  However, when a civil project is considered, the head contractor sees most of the benefits because subcontractors only control 17% of the costs.  The resource sector has some interesting statistics as well.  First of all, for a pipeline, the indirect cost is far greater at 45% of the cost going to head contractors.  In addition, the head contractor owns the material production plant/labor and the resulting cost accounts for 83% percent of the other 55% which amounts to an additional 46% of the direct cost and 91% of the overall cost.  Therefore, in this case, the head contractor holds a large portion of the cost control.  However, when building a refinement plant there are some critical differences.  There is a similar level of indirect cost cost at 45%, but the subcontractor sees 88% of the direct cost in this case.  The result is the subcontractor seeing 48% of the cost of the project as compared to 9% in the previous example.

The above statistics are interesting for several reasons.  The first one, as stated in the article, is the fact that BIM modeling is implemented by head contractor and other associated designers; yet in some cases, the subcontractors see the benefits.  Seeing as changes in pricing are based on estimation based on previous projects, pricing benefits aren’t planned for in the budget as efficiently, and, depending on the project and head contractor, a subcontractor could see large and consistent benefits.  This means that the benefits of using BIM might not be maximized aside from time and documentation for the head contractor in that situation.  And if it is a case where head contractors see a large amount of the cost savings, they can more readily pass along the cost saving of BIM modeling. But the subcontractors may not be motivated to help improve the BIM modeling because it doesn’t help their bottom line.  For both of these reason, it makes sense why it is most common for head contractors and designers to push for improvements and BIM modeling.  However, an often overlooked requirement is that the subcontractor needs to work with the head contractor in implementing the improvements and have proper motivation to pass along the savings the see the full benefit for everyone involved with the project.

What is your opinion on BIM model implementation in regards to subcontractors and head contractors?  Are there any ways to promote a shared interest in BIM modeling?  Thanks for your time and have a good week!

The Application of Biologically Grown Materials to Building Design

Hello everyone, I hope y’all had good weekend.  Today, I want to talk about some new building materials being researched that are biological produced in a replicable process.  One of the common characteristics is that these materials will involve bacteria or something else derived from organisms.  The fact that these materials don’t require significant carbon output is one major benefit.  Another benefit for most of these materials is that they are actively reproduced over time once they are installed as well.  The building materials are described below with some insight on possible benefits and issues.

bioMason Brickshttp://goo.gl/PY68HQ

The bioMason brick is a brick of sand and cementitious material in which the cementitious material is created using a bacteria.  The brick mixture is created and over the course of 5 days the bacteria solidifies into a coral type material with the strength of a normal brick.  The major benefit for this innovation is that it doesn’t require the heat and raw materials used in creating normal bricks; this reduces the cost of the brick by 40%.  They are currently conducting experiments to research bacteria creation using the following materials: urea, salt and yeast extracts, and seawater.

I see this having one major benefit – it would not significantly change the design and build process for masonry.  Masonry strength is mostly determined by the strength of the mortar as long as the masonry unit strength doesn’t change significantly.  The benefits of the bioMason bricks combined with the low technology change requirement makes this much more effective.

Mushroom Insulation Materialhttp://goo.gl/SZcfA

This is a stiff insulation material using plant stalks and husks combined with Mycelium.  There are two forms of application being tested currently: growth inside the wall and spray on insulation.  The insulation is fire resistant and fully compostable.  Additionally, it does not contain formaldehyde or any other harmful organic materials.  This same material can also be used as compostable packaging material.

There are several benefits to this material.  Like before there is no significant change to the other building processes related to it.  It also has great applications outside of this usage alone and is completely compostable once it is not needed anymore.  The only drawback I can potentially see is there being an organic material harmful to humans that is unknown as of yet – similar to what happened with Asbestos. It has great potential overall though – it is my recommendation that more health testing be done before large scale usage.

Self Repairing Concrete:

Research is being conducted on a bacteria that can be used to repair concrete as it ages.  Bacteria engineered to thrive in dry climates is being created to be placed in the concrete mixture.  The bacteria would release Calcium Carbonate as part of the waste process which would fill the holes and cracks over time.

There is one possible major benefit I see – the reduction in maintenance required for the concrete designed this way.  However, more research would be required to determine it’s efficiency.  Additionally, nothing is mentioned about resources and energy required to produce this bacteria; if it requires a high amount of energy and time/raw material resources, it may become impractical to use.  I might also add that the issue of infection might come up here as well; but if the claim is true that it is bacteria that thrives in dry climates, the danger to living organisms would be greatly reduced.

What is your opinion on these possible advancements?  Can you see them being used in the future?  Thank you for your time and have a good week!

Reference:

Wollenhaupt, Gary,”Self-Repairing Concrete Could be the Future of Green Building”, Forbes Online, January 6, 2014, http://goo.gl/IRyzHi

High Performance Energy Saving Design for the Karuna House – Window/Door Design

Passive House Green Home Building Tips: Karuna House Windows & Doors

Hello everyone! Today I would like to go back to my series of posts outlining the design and construction of the Karuna House.  The topic for this post will be the selection and resulting benefits of the improved windows and doors.  Windows and doors are the biggest holes in the building envelope above ground.  These innovations are what allow the HVAC systems to reach their maximum efficiency.  Additionally, windows and doors are also a major aesthetic concern and these aesthetic factors play a big role in the decision process.

The Karuna House uses triple glazed, high solar heat gain, R-8 windows with a very thin frame.  This type of window has an increased level of heat gain, but significantly improves the building envelope by allowing additional insulation to be placed around the frame.  The triple glazed window also has a well documented performance history because it has been in use since the 70’s in Scandinavia.  For the exterior doors, the Karuna House uses Optiwin doors.  These doors are thick with insulation in the middle and airtight with multi-locking mechanisms to ensure a tight seal.  To help with the heat gain issue for the windows, a shading system that can be lowered over the windows was installed.  This has an additional benefit of being modern and aesthetically appealing.  The triple glazing also provides a very clear view through the glass which adds to the modern, aesthetic appeal.  To further improve indoor conditions, these windows and doors increase comfort by reducing the draft found near the window and door openings.  All of the benefits above combine to reduce the impact on the mechanical systems which allows for a simpler, more efficient system to be used.

Overall these systems are simple and nothing too complex.  However, these systems apply the same philosophy that is applied to the building envelope in general – simple and efficient solutions to problems.  Furthermore, the philosophy applied to the building envelope, windows, and doors altogether should reap a lot of benefits for the mechanical systems and the energy usage correlated to that.  The take away here is very similar to the previous post on the Karuna House – a little a effort put into finding cost efficient improvements to small elements of the house can improve the overall efficiency a lot.

What do you think about the window and door improvements on the Karuna House?  Are there any issues that need to be addressed or  improvements that can be made?  Thanks for your time and have a good week!

Resource:

Hammer & Hand,”Karuna House: Windows and Doors”, http://goo.gl/j7zAAy

High Performance Energy Saving Design for the Karuna House – Wall System

Passive House Green Home Building Tips: Karuna House Wall Assembly

Hello everyone.  I hope your weekend went well.  Everything is picking up for me again – my day job and school included.  Not in a stressful way though; it feels good to be doing some productive stuff again.  Today, I want share the second part of my series of post describing the design of the Karuna House and the topic this time around will be the wall system.

As stated in the article, the main issues in designing the wall were moisture, heat and air control.  Along with that, this design added the other standard of being able to release moisture once it entered the system as well.  With that in mind, the main goal of the wall design was to create a building envelope that was air tight, water tight, vapor permeable and super insulated.  On the inside of the wall, standard natural lime coating and dry wall were used for interior design purposes.  Beneath that, a stud frame of engineered wood members was built to support the wall structure and was insulated with high density cellulose.   The high density cellulose consisted of recycled newspaper and naturally buffered against moisture which improved the walls durability.  After that, there was the air barrier which prevented air from flowing through the wall and allowed the insulation to perform at a much higher level.  The air barrier was created using plywood coated with vapor permeable liquid applied membrane.  After that level, a frame of Z Joists with foil faced Polyiso Foam was placed over that.  This element was the critical part of the design in regards to performance and durability.  The final element was the rain screen system made out of cedar siding placed 1 inch off of the Polyiso Foam.  Window frames were sealed using Joint Seam Filler and Fast Flash around the window structure.  Details aren’t provided about door frames but it would be a reasonable assumption that they did the same thing there as well.

In my opinion, the design of the wall framing system isn’t as unique as the foundation system.  It has been standard practice for a while to use foam insulation and air barriers.  The same goes for the window sealant process.  However, the attention to detail in what to use and how to apply it is still a good take away for building design in the future.

What is your opinion on the wall frame system?  Is there any improvement they could have made that would have increased energy efficiency?  Thanks for your time and have a good week! 🙂

Source:

Hammer and Hand, “The Karuna House: Wall Assembly”, http://goo.gl/sHU7kv

High Performance Energy Saving Design for the Karuna House Part 1 – Foundation Design

     Hello everyone! I hope your holiday break went well.  I had a fun time with my family and definitely felt like I recharged my batteries as well. Hopefully you guys could do the same.  Today I want to start a series of blog posts on a detailed overview of the high performance systems used in the Karuna House created by Holst Architecture and Hammer & Hand.

The Karuna House is a house designed to meet Passive House standards, Minergie-P-ECO, and Platinum LEED Home Standards.  The client is a leading proponent of high performance design technology for climate control.  This house is intended to be a case study in the usage of the current technology on the market today.  In the first part of this blog post series, I am going to discuss the design of the foundation and the energy saving technology applied in that part of the design.

The main concern for the foundation involved insulating the basement and foundation.  With that in mind, most of the technology focuses on maintaining a good quality building envelope that insulates well.  The first step was the cut and fill for the excavation.  In this step, the cut was balanced with the fill to ensure that there wasn’t a need to haul around aggregate to complete the fill process.  For the next step, an Expanded Polystyrene (EPS) geofoam foundation insulation was placed around the cut and fill earthwork before the concrete foundation was constructed.  Next, the footings beneath the structure were placed and a moisture blocking capillery break material was placed on top of that.  Once the footings were in place, gravel fill was placed for the foundation base and the basement foundation wall was constructed with a vapor barrier extending to both sides of the wall.  The concrete mix used in the basement foundation wall consisted of 30% fly ash and used locally sourced aggregate.  In order to obtain better energy efficiency, EPS was placed in critical thermal bridge sections.  Along the foundation walls, a product called a drain board was applied to it’s surface as well to allow water to flow down the foundation walls and past the footings.  Once all that was completed, they applied the vapor barrier over the gravel base and laid some more EPS foam before they constructed the slab portion of the foundation.

My take away from reading the article and watching the videos is that there are two critical issues that affect house foundations – moisture control and thermal bridging.  The designers used the EPS and vapor barriers to address these issues.  Along with that, methods of construction were used that reduce the use of energy/material in construction as well.  Overall, I think this was a good application of some practical design ideas.  A lot of designs like this get caught up in following the latest complex and cool looking trend instead of finding a solid and fundamental solution to the problem – this design avoids that fairly well.

What are your thoughts on the design?  Does it seem like a practical application to use for increased energy efficiency?  Any issues you worry about over it’s life cycle?  Thanks for your time and have a good week! 🙂

Source:

Hammer and Hand, “The Karuna House: Foundation System”, http://goo.gl/C9Hccu

Advancements in Resilient Timber Design

Hello everyone. I hope y’all are doing well.  I’m looking forward to Christmas and I hope you are too.  Just in case I decide to not do a post before Christmas I just want to wish y’all a Merry Christmas.  Today I want to talk about some advancements in timber design taking place in the multi-family residential building industry in California.

In California, residential structures can be vulnerable to seismic loads – especially if there is an open floor plan on the bottom.  Engineering professor John van de Lint from Colorado State University has been leading a team of researchers in that specific area of study as it pertains to first floor garages.  He has previously completed similar research with Simpson Strong Tie in 2009 in regards to natural disasters and it led to the consideration of timber for mid-rise structures with high seismic loads.  According to Lint, “Earthquakes are particularly damaging to buildings with open spaces at street level because they collapse – the first-floor parking makes the building structurally weak and soft…There are tens of thousands of these multi-family buildings throughout California and much of the U.S., making this a serious safety issue.”  The team has tested several concepts for earthquake retrofitting on structures designed to replicate common California architectural practices.

A common characteristic among all the models they tested is a timber frame structure with an open structure on the first floor and a purely timber structure on the upper floors.  Some of the retrofits followed the FEMA P-807 guideline because that is the current retrofit requirement in California.  This law requires that buildings with a soft story be retrofitted within the next several years.   One of the retrofits tested is cross laminated timber.  In this test, the shear walls are constructed with cross laminated timber and the floor diaphram is reinforced using plywood and attached to the shear walls using Simpson Strong Tie straps and clips.  The test was successful up to 50% Maximum Credible Earthquake (MCE).

The article also mentions some innovations for dealing with harsher environments.  In locations with more humidity and rain, protection from the elements can be a critical issue for timber frames.  Huber Engineered Woods has developed a material called ZIP System R Sheathing for the construction of walls where protecting the structure against the elements is critical.  This is currently the first product of it’s kind to be approved by the International Building Code.  This sheathing provides protection against bulk water, thermal, air and moisture resistance while being strong and durable.  The sheathing also provides increased energy efficiency for HVAC systems.  This system has advantages over regular plywood or oriented strand board in harsher climates because an additional layer of house wrap and hurricane clips is not required.

Both of these improvements may seem a bit generic at first.  In fact, the more I think about the descriptions above, the more I think of an advertisement pamphlet you might get from a timber supplier.  However, it is my opinion that these are significant advancements for the future of timber usage.  These two situations above are textbook reasons for the usage of a material other than timber for taller buildings in these seismic or weather critical locations.  With the proper implementation of these advancements in the future, the use of timber can be expanded to a larger variety of locations.  The only major drawbacks I see are the increased cost of using the materials and the necessity for contractors with experience implementing these designs.

Do you see these products changing the use of timber on a larger scale?  If so, how and why?  If not, what is the critical issue that has to be overcome?  Thanks for your time and have a good week!

Resources

Zweig, Christina, “Resiliant Wood: New Wood Products Help Cope with Nature’s Challenges”, Structural Engineer Magazine, November, 2013, http://goo.gl/NoJT9Z

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