GN
G. Nijenhuis
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3 records found
1
Sheet pile walls are a key part of Dutch maritime infrastructure. As these structures age, inspections are becoming increasingly important, particularly in areas where corrosion is difficult to detect. Current inspection methods, such as divers, cofferdams, and elevated platforms, are effective, but they are often slow, costly, and disruptive to daily port operations. This project, carried out in collaboration with AquaSmartXL, explores how a different type of inspection platform could make the inspection process more efficient.
The research phase mapped out what makes sheet pile inspection difficult. Corrosion concentrates in the splash zone and near the mudline, underwater visibility is unpredictable, and while sheet pile profiles vary widely, their outer face remains consistently flat and free of obstacles such as anchor heads. These findings pointed toward a clear direction: a platform that attaches to the outer surface, moves vertically along the wall, and carries swappable modules for cleaning, measuring, or visual inspection.
Several attachment methods were tested early on. Clamping failed because the angled sheet pile profile caused gripping forces to slide off rather than lock on, and suction could not form a reliable seal on corroded, uneven steel. Magnetic wheels performed best, but attaching and detaching them safely required addressing how strongly and unpredictably the magnetic pull increases at close range. This led to a ramp-shaped separator mechanism that gradually increases the distance between the magnets and the steel, releasing the wheels smoothly instead of forcing them off.
A working prototype combining magnetic wheels, thrusters, and the separator was built and tested in a water-filled sea container used as a stand-in for a sheet pile wall. The thrusters moved and aligned the prototype reliably, the magnetic wheels held firmly even when wet, and the separator released the wheels consistently, with an average gap of 4.91 mm before detachment. Belt tension proved more important than expected, as insufficient tension caused the drive belt to skip under the magnetic load.
The tests show that combining magnetic wheels, thrusters, and a separator mechanism allows a platform to move, attach, climb, and detach from a steel surface underwater. Building on this, a final concept was developed: the SP Crawler, a modular platform that can be fitted with different inspection tools depending on the task. Testing on real sheet piles, with marine growth and corrosion present, is needed to confirm how the system performs outside a controlled test setup. ...
The research phase mapped out what makes sheet pile inspection difficult. Corrosion concentrates in the splash zone and near the mudline, underwater visibility is unpredictable, and while sheet pile profiles vary widely, their outer face remains consistently flat and free of obstacles such as anchor heads. These findings pointed toward a clear direction: a platform that attaches to the outer surface, moves vertically along the wall, and carries swappable modules for cleaning, measuring, or visual inspection.
Several attachment methods were tested early on. Clamping failed because the angled sheet pile profile caused gripping forces to slide off rather than lock on, and suction could not form a reliable seal on corroded, uneven steel. Magnetic wheels performed best, but attaching and detaching them safely required addressing how strongly and unpredictably the magnetic pull increases at close range. This led to a ramp-shaped separator mechanism that gradually increases the distance between the magnets and the steel, releasing the wheels smoothly instead of forcing them off.
A working prototype combining magnetic wheels, thrusters, and the separator was built and tested in a water-filled sea container used as a stand-in for a sheet pile wall. The thrusters moved and aligned the prototype reliably, the magnetic wheels held firmly even when wet, and the separator released the wheels consistently, with an average gap of 4.91 mm before detachment. Belt tension proved more important than expected, as insufficient tension caused the drive belt to skip under the magnetic load.
The tests show that combining magnetic wheels, thrusters, and a separator mechanism allows a platform to move, attach, climb, and detach from a steel surface underwater. Building on this, a final concept was developed: the SP Crawler, a modular platform that can be fitted with different inspection tools depending on the task. Testing on real sheet piles, with marine growth and corrosion present, is needed to confirm how the system performs outside a controlled test setup. ...
Sheet pile walls are a key part of Dutch maritime infrastructure. As these structures age, inspections are becoming increasingly important, particularly in areas where corrosion is difficult to detect. Current inspection methods, such as divers, cofferdams, and elevated platforms, are effective, but they are often slow, costly, and disruptive to daily port operations. This project, carried out in collaboration with AquaSmartXL, explores how a different type of inspection platform could make the inspection process more efficient.
The research phase mapped out what makes sheet pile inspection difficult. Corrosion concentrates in the splash zone and near the mudline, underwater visibility is unpredictable, and while sheet pile profiles vary widely, their outer face remains consistently flat and free of obstacles such as anchor heads. These findings pointed toward a clear direction: a platform that attaches to the outer surface, moves vertically along the wall, and carries swappable modules for cleaning, measuring, or visual inspection.
Several attachment methods were tested early on. Clamping failed because the angled sheet pile profile caused gripping forces to slide off rather than lock on, and suction could not form a reliable seal on corroded, uneven steel. Magnetic wheels performed best, but attaching and detaching them safely required addressing how strongly and unpredictably the magnetic pull increases at close range. This led to a ramp-shaped separator mechanism that gradually increases the distance between the magnets and the steel, releasing the wheels smoothly instead of forcing them off.
A working prototype combining magnetic wheels, thrusters, and the separator was built and tested in a water-filled sea container used as a stand-in for a sheet pile wall. The thrusters moved and aligned the prototype reliably, the magnetic wheels held firmly even when wet, and the separator released the wheels consistently, with an average gap of 4.91 mm before detachment. Belt tension proved more important than expected, as insufficient tension caused the drive belt to skip under the magnetic load.
The tests show that combining magnetic wheels, thrusters, and a separator mechanism allows a platform to move, attach, climb, and detach from a steel surface underwater. Building on this, a final concept was developed: the SP Crawler, a modular platform that can be fitted with different inspection tools depending on the task. Testing on real sheet piles, with marine growth and corrosion present, is needed to confirm how the system performs outside a controlled test setup.
The research phase mapped out what makes sheet pile inspection difficult. Corrosion concentrates in the splash zone and near the mudline, underwater visibility is unpredictable, and while sheet pile profiles vary widely, their outer face remains consistently flat and free of obstacles such as anchor heads. These findings pointed toward a clear direction: a platform that attaches to the outer surface, moves vertically along the wall, and carries swappable modules for cleaning, measuring, or visual inspection.
Several attachment methods were tested early on. Clamping failed because the angled sheet pile profile caused gripping forces to slide off rather than lock on, and suction could not form a reliable seal on corroded, uneven steel. Magnetic wheels performed best, but attaching and detaching them safely required addressing how strongly and unpredictably the magnetic pull increases at close range. This led to a ramp-shaped separator mechanism that gradually increases the distance between the magnets and the steel, releasing the wheels smoothly instead of forcing them off.
A working prototype combining magnetic wheels, thrusters, and the separator was built and tested in a water-filled sea container used as a stand-in for a sheet pile wall. The thrusters moved and aligned the prototype reliably, the magnetic wheels held firmly even when wet, and the separator released the wheels consistently, with an average gap of 4.91 mm before detachment. Belt tension proved more important than expected, as insufficient tension caused the drive belt to skip under the magnetic load.
The tests show that combining magnetic wheels, thrusters, and a separator mechanism allows a platform to move, attach, climb, and detach from a steel surface underwater. Building on this, a final concept was developed: the SP Crawler, a modular platform that can be fitted with different inspection tools depending on the task. Testing on real sheet piles, with marine growth and corrosion present, is needed to confirm how the system performs outside a controlled test setup.
Democratising design for Down Syndrome
A DfDIY buildkit for makers with Down syndrome
This thesis explores how the Design for Do-It-Yourself (DfDIY) framework can be adapted to develop a toolkit that facilitates independence, skill acquisition and fosters a sense of pride of authorship for young adults with Down syndrome, advancing the democratisation of design.
The DfDIY framework, developed by Hoftijzer (2024), argues that designers should shift from creators of finished products to facilitators who enable others to make, modify and take ownership of what they build. However, the framework implicitly assumes a ‘layperson’ with neurotypical cognitive abilities and standard physical dexterity. This restricts the participation of people with intellectual disabilities in maker environments. This project identifies that gap and addresses it through the development of an inclusive DfDIY buildkit specifically designed for young adults with Down syndrome.
A literature review across five sub-research questions examined the current state of DIY for people with intellectual disabilities, the physical and cognitive barriers specific to Down syndrome, relevant pedagogical frameworks from special education, the concept of pride of authorship for this demographic and methods for evaluating toolkit effectiveness. The findings informed a set of eighteen design guidelines for an inclusive DfDIY toolkit, covering accessible components, embedded and visual instructions, scaffolded independence, errorless learning, co-creation through tangible choice systems and aesthetic scaffolding.
These findings were translated into a set of requirements and design guidelines that informed the development of Down to Make. Down to make is a brand that develops buildkits for young adults with Down syndrome, each enabling users to independently learn new cognitive or physical making skills, experience a sense of pride of authorship and participate as active makers in the design process. The screen-printing kit described in this thesis is the first kit in the Down to Make range and served as the case study through which the core methodology was developed and tested. The kit includes a layered instructional system combining a full instructional video, a laminated step-by-step booklet and physical cues embedded directly into the components. A colour-coded choice card system placed on a placemat gives users creative agency over what they make, what colour they use and what design they print. The kit was developed by research through design, an expert review and two rounds of user testing with fifteen young adults with Down syndrome aged seventeen to twenty-five.
The testing confirmed that when the instructional system, physical components and choice architecture are designed to remove barriers rather than compensate for them, participants engage independently with a (complex) making task and produce results they are genuinely proud of. Facilitator interventions dropped significantly between iterations and participants consistently demonstrated more independence than their teachers and caregivers had expected. Every participant across both rounds wanted to show their finished object to someone, a clear and consistent indicator of pride of authorship.
The thesis concludes with a set of thirty-eight design guidelines for future designers who want to develop similar kits, covering activity selection, kit design, facilitation and evaluation. These guidelines are intended to be applicable across a wide range of making techniques and to serve as a starting point for extending the democracy of design to people with Down Syndrome and possibly other cognitive disabilities.
...
The DfDIY framework, developed by Hoftijzer (2024), argues that designers should shift from creators of finished products to facilitators who enable others to make, modify and take ownership of what they build. However, the framework implicitly assumes a ‘layperson’ with neurotypical cognitive abilities and standard physical dexterity. This restricts the participation of people with intellectual disabilities in maker environments. This project identifies that gap and addresses it through the development of an inclusive DfDIY buildkit specifically designed for young adults with Down syndrome.
A literature review across five sub-research questions examined the current state of DIY for people with intellectual disabilities, the physical and cognitive barriers specific to Down syndrome, relevant pedagogical frameworks from special education, the concept of pride of authorship for this demographic and methods for evaluating toolkit effectiveness. The findings informed a set of eighteen design guidelines for an inclusive DfDIY toolkit, covering accessible components, embedded and visual instructions, scaffolded independence, errorless learning, co-creation through tangible choice systems and aesthetic scaffolding.
These findings were translated into a set of requirements and design guidelines that informed the development of Down to Make. Down to make is a brand that develops buildkits for young adults with Down syndrome, each enabling users to independently learn new cognitive or physical making skills, experience a sense of pride of authorship and participate as active makers in the design process. The screen-printing kit described in this thesis is the first kit in the Down to Make range and served as the case study through which the core methodology was developed and tested. The kit includes a layered instructional system combining a full instructional video, a laminated step-by-step booklet and physical cues embedded directly into the components. A colour-coded choice card system placed on a placemat gives users creative agency over what they make, what colour they use and what design they print. The kit was developed by research through design, an expert review and two rounds of user testing with fifteen young adults with Down syndrome aged seventeen to twenty-five.
The testing confirmed that when the instructional system, physical components and choice architecture are designed to remove barriers rather than compensate for them, participants engage independently with a (complex) making task and produce results they are genuinely proud of. Facilitator interventions dropped significantly between iterations and participants consistently demonstrated more independence than their teachers and caregivers had expected. Every participant across both rounds wanted to show their finished object to someone, a clear and consistent indicator of pride of authorship.
The thesis concludes with a set of thirty-eight design guidelines for future designers who want to develop similar kits, covering activity selection, kit design, facilitation and evaluation. These guidelines are intended to be applicable across a wide range of making techniques and to serve as a starting point for extending the democracy of design to people with Down Syndrome and possibly other cognitive disabilities.
...
This thesis explores how the Design for Do-It-Yourself (DfDIY) framework can be adapted to develop a toolkit that facilitates independence, skill acquisition and fosters a sense of pride of authorship for young adults with Down syndrome, advancing the democratisation of design.
The DfDIY framework, developed by Hoftijzer (2024), argues that designers should shift from creators of finished products to facilitators who enable others to make, modify and take ownership of what they build. However, the framework implicitly assumes a ‘layperson’ with neurotypical cognitive abilities and standard physical dexterity. This restricts the participation of people with intellectual disabilities in maker environments. This project identifies that gap and addresses it through the development of an inclusive DfDIY buildkit specifically designed for young adults with Down syndrome.
A literature review across five sub-research questions examined the current state of DIY for people with intellectual disabilities, the physical and cognitive barriers specific to Down syndrome, relevant pedagogical frameworks from special education, the concept of pride of authorship for this demographic and methods for evaluating toolkit effectiveness. The findings informed a set of eighteen design guidelines for an inclusive DfDIY toolkit, covering accessible components, embedded and visual instructions, scaffolded independence, errorless learning, co-creation through tangible choice systems and aesthetic scaffolding.
These findings were translated into a set of requirements and design guidelines that informed the development of Down to Make. Down to make is a brand that develops buildkits for young adults with Down syndrome, each enabling users to independently learn new cognitive or physical making skills, experience a sense of pride of authorship and participate as active makers in the design process. The screen-printing kit described in this thesis is the first kit in the Down to Make range and served as the case study through which the core methodology was developed and tested. The kit includes a layered instructional system combining a full instructional video, a laminated step-by-step booklet and physical cues embedded directly into the components. A colour-coded choice card system placed on a placemat gives users creative agency over what they make, what colour they use and what design they print. The kit was developed by research through design, an expert review and two rounds of user testing with fifteen young adults with Down syndrome aged seventeen to twenty-five.
The testing confirmed that when the instructional system, physical components and choice architecture are designed to remove barriers rather than compensate for them, participants engage independently with a (complex) making task and produce results they are genuinely proud of. Facilitator interventions dropped significantly between iterations and participants consistently demonstrated more independence than their teachers and caregivers had expected. Every participant across both rounds wanted to show their finished object to someone, a clear and consistent indicator of pride of authorship.
The thesis concludes with a set of thirty-eight design guidelines for future designers who want to develop similar kits, covering activity selection, kit design, facilitation and evaluation. These guidelines are intended to be applicable across a wide range of making techniques and to serve as a starting point for extending the democracy of design to people with Down Syndrome and possibly other cognitive disabilities.
The DfDIY framework, developed by Hoftijzer (2024), argues that designers should shift from creators of finished products to facilitators who enable others to make, modify and take ownership of what they build. However, the framework implicitly assumes a ‘layperson’ with neurotypical cognitive abilities and standard physical dexterity. This restricts the participation of people with intellectual disabilities in maker environments. This project identifies that gap and addresses it through the development of an inclusive DfDIY buildkit specifically designed for young adults with Down syndrome.
A literature review across five sub-research questions examined the current state of DIY for people with intellectual disabilities, the physical and cognitive barriers specific to Down syndrome, relevant pedagogical frameworks from special education, the concept of pride of authorship for this demographic and methods for evaluating toolkit effectiveness. The findings informed a set of eighteen design guidelines for an inclusive DfDIY toolkit, covering accessible components, embedded and visual instructions, scaffolded independence, errorless learning, co-creation through tangible choice systems and aesthetic scaffolding.
These findings were translated into a set of requirements and design guidelines that informed the development of Down to Make. Down to make is a brand that develops buildkits for young adults with Down syndrome, each enabling users to independently learn new cognitive or physical making skills, experience a sense of pride of authorship and participate as active makers in the design process. The screen-printing kit described in this thesis is the first kit in the Down to Make range and served as the case study through which the core methodology was developed and tested. The kit includes a layered instructional system combining a full instructional video, a laminated step-by-step booklet and physical cues embedded directly into the components. A colour-coded choice card system placed on a placemat gives users creative agency over what they make, what colour they use and what design they print. The kit was developed by research through design, an expert review and two rounds of user testing with fifteen young adults with Down syndrome aged seventeen to twenty-five.
The testing confirmed that when the instructional system, physical components and choice architecture are designed to remove barriers rather than compensate for them, participants engage independently with a (complex) making task and produce results they are genuinely proud of. Facilitator interventions dropped significantly between iterations and participants consistently demonstrated more independence than their teachers and caregivers had expected. Every participant across both rounds wanted to show their finished object to someone, a clear and consistent indicator of pride of authorship.
The thesis concludes with a set of thirty-eight design guidelines for future designers who want to develop similar kits, covering activity selection, kit design, facilitation and evaluation. These guidelines are intended to be applicable across a wide range of making techniques and to serve as a starting point for extending the democracy of design to people with Down Syndrome and possibly other cognitive disabilities.
From Blade to Barrier
The embodiment design of a noise barrier from horizontally oriented, decommissioned wind turbine blades
This thesis proposes a design with the reuse of decommissioned wind turbine blades (WTBs) as structural elements in highway noise barriers. While wind energy continues to grow rapidly, the decommissioning of turbines is generating a large and increasing stream of composite blade waste. This waste is difficult to recycle and often disposed through environmentally harmful methods such as landfilling or incineration. At the same time, WTBs still possess valuable mechanical properties that make them suitable for structural reuse applications.
The research develops and tests a modular noise barrier concept in which 12-meter blade segments are horizontally placed into U-shaped steel frames. The design takes advantage of the natural blade curvature to improve acoustic performance, while focusing on ease of assembly, durability, safety standards and drainage. Key features include capped and sealed segment ends, anti-graffiti coatings, acoustic cover strips, and integrated emergency exits.
The resulting concept demonstrates that WTBs can be repurposed into feasible, scalable, and structurally reliable noise barriers. The design offers a circular way for storing composite material until advanced recycling technologies become more widely available to reuse it, while it acts as a functional noise barrier. While further development is required in areas such as logistics, cost, and market acceptance, this thesis highlights the potential of structural reuse to extend the material life of blades and contribute to more sustainable infrastructure projects. ...
The research develops and tests a modular noise barrier concept in which 12-meter blade segments are horizontally placed into U-shaped steel frames. The design takes advantage of the natural blade curvature to improve acoustic performance, while focusing on ease of assembly, durability, safety standards and drainage. Key features include capped and sealed segment ends, anti-graffiti coatings, acoustic cover strips, and integrated emergency exits.
The resulting concept demonstrates that WTBs can be repurposed into feasible, scalable, and structurally reliable noise barriers. The design offers a circular way for storing composite material until advanced recycling technologies become more widely available to reuse it, while it acts as a functional noise barrier. While further development is required in areas such as logistics, cost, and market acceptance, this thesis highlights the potential of structural reuse to extend the material life of blades and contribute to more sustainable infrastructure projects. ...
This thesis proposes a design with the reuse of decommissioned wind turbine blades (WTBs) as structural elements in highway noise barriers. While wind energy continues to grow rapidly, the decommissioning of turbines is generating a large and increasing stream of composite blade waste. This waste is difficult to recycle and often disposed through environmentally harmful methods such as landfilling or incineration. At the same time, WTBs still possess valuable mechanical properties that make them suitable for structural reuse applications.
The research develops and tests a modular noise barrier concept in which 12-meter blade segments are horizontally placed into U-shaped steel frames. The design takes advantage of the natural blade curvature to improve acoustic performance, while focusing on ease of assembly, durability, safety standards and drainage. Key features include capped and sealed segment ends, anti-graffiti coatings, acoustic cover strips, and integrated emergency exits.
The resulting concept demonstrates that WTBs can be repurposed into feasible, scalable, and structurally reliable noise barriers. The design offers a circular way for storing composite material until advanced recycling technologies become more widely available to reuse it, while it acts as a functional noise barrier. While further development is required in areas such as logistics, cost, and market acceptance, this thesis highlights the potential of structural reuse to extend the material life of blades and contribute to more sustainable infrastructure projects.
The research develops and tests a modular noise barrier concept in which 12-meter blade segments are horizontally placed into U-shaped steel frames. The design takes advantage of the natural blade curvature to improve acoustic performance, while focusing on ease of assembly, durability, safety standards and drainage. Key features include capped and sealed segment ends, anti-graffiti coatings, acoustic cover strips, and integrated emergency exits.
The resulting concept demonstrates that WTBs can be repurposed into feasible, scalable, and structurally reliable noise barriers. The design offers a circular way for storing composite material until advanced recycling technologies become more widely available to reuse it, while it acts as a functional noise barrier. While further development is required in areas such as logistics, cost, and market acceptance, this thesis highlights the potential of structural reuse to extend the material life of blades and contribute to more sustainable infrastructure projects.