Matching Items (8)

Life Cycle Assessment of Ecosystem Services for Phoenix’s Building Stock

Description

Better methods are necessary to fully account for anthropogenic impacts on ecosystems and the essential services provided by ecosystems that sustain human life. Current methods for assessing sustainability, such as

Better methods are necessary to fully account for anthropogenic impacts on ecosystems and the essential services provided by ecosystems that sustain human life. Current methods for assessing sustainability, such as life cycle assessment (LCA), typically focus on easily quantifiable indicators such as air emissions with no accounting for the essential ecosystem benefits that support human or industrial processes. For this reason, more comprehensive, transparent, and robust methods are necessary for holistic understanding of urban technosphere and ecosphere systems, including their interfaces. Incorporating ecosystem service indicators into LCA is an important step in spanning this knowledge gap.

For urban systems, many built environment processes have been investigated but need to be expanded with life cycle assessment for understanding ecosphere impacts. To pilot these new methods, a material inventory of the building infrastructure of Phoenix, Arizona can be coupled with LCA to gain perspective on the impacts assessment for built structures in Phoenix. This inventory will identify the origins of materials stocks, and the solid and air emissions waste associated with their raw material extraction, processing, and construction and identify key areas of future research necessary to fully account for ecosystem services in urban sustainability assessments. Based on this preliminary study, the ecosystem service impacts of metropolitan Phoenix stretch far beyond the county boundaries. A life cycle accounting of the Phoenix’s embedded building materials will inform policy and decision makers, assist with community education, and inform the urban sustainability community of consequences.

Contributors

155204-Thumbnail Image.png

Experimental study of cement stabilized fiber reinforced compressed earth blocks as an alternative building material

Description

Concern and interest about the environment and ecologic systems have promoted the usage of earth as a construction material. Technology advancement has resulted in the evolution of adobe into compressed

Concern and interest about the environment and ecologic systems have promoted the usage of earth as a construction material. Technology advancement has resulted in the evolution of adobe into compressed stabilized earth blocks (CSEB). CSEB’s are prepared by compressing the soil-stabilizer mixture at a particular stress. In order to accomplish the required strength, cement has been used in a regular basis as stabilizing agent. It is of interest to find means to reduce the cement used in their construction without affecting its dry strength and durability. In this study, natural fibers were used along with lower proportions of cement to stabilize soil with varying fine content. Blocks were compacted at 10MPa stress and prepared by using 7%, 5% and 3% cement along with fiber content ranging from 0.25% to 2%. The effect of fine content, cement and fibers on strength and durability of the CSEB blocks were studied. Different sand/fine fractions of a native Arizona soil were used to fabricate the blocks. Results indicate that the compressive strength reaches a maximum value for blocks with 30% fine content and inclusion of fibers up to 0.5% increased the dry compressive strength. The use of 0.25% fiber by weight and 5% cement content showed comparable dry compressive strength to that of the 7% cement blocks with no fibers. The dry strength of the blocks reached an optimal condition when the combination of materials was 30% fines, 5% cement and 0.5% fibers, which satisfied the strength requirement given by the ASTM C62 and ASTM C216 standards for construction material. The CSEB’s with 0.5% fiber had higher toughness. The durability was determined by subjecting the CSEBs to wetting and drying cycles. The blocks with 5% cement withstand the durability test as the dry strength was higher than that required for construction use.

The blocks were also submitted to heating and cooling cycles. After 12 cycles, the specimens showed a reduction in strength, which further increased as the number of cycles increased. Finally, the thermal resistivity of fiber reinforced CSEB was found to be higher than that for clay bricks.

Contributors

Agent

Created

Date Created
  • 2016

157952-Thumbnail Image.png

Determining the designer's awareness of sustainable interior materials in Saudi Arabia

Description

The main aim of this thesis is to study the Saudi Arabia designers level of awareness about sustainable interior materials and to what extent are Saudi Arabia designers specifying sustainable

The main aim of this thesis is to study the Saudi Arabia designers level of awareness about sustainable interior materials and to what extent are Saudi Arabia designers specifying sustainable interior materials in their interior designs? The problem statement relies on understanding how does this may impact the Saudi Arabia environment. In order to comply with these objectives, a telephone interviews were built, to test the designer’s knowledge about sustainable interior materials. The results showed that the Saudi Arabia interior designers are not fully aware of sustainable interior materials and there is a lack of interest in applying sustainable interior materials in their projects.

Contributors

Agent

Created

Date Created
  • 2019

154897-Thumbnail Image.png

Numerical and experimental investigation of laser-induced optoacoustic wave propagation for damage detection

Description

An integrated experimental and numerical investigation for laser-generated optoacoustic wave propagation in structural materials is performed. First, a multi-physics simulation model is proposed to simulate the pulsed laser as a

An integrated experimental and numerical investigation for laser-generated optoacoustic wave propagation in structural materials is performed. First, a multi-physics simulation model is proposed to simulate the pulsed laser as a point heat source which hits the surface of an aluminum sheet. The pulsed laser source can generate a localized heating on the surface of the plate and induce an in-plane stress wave. ANSYS – a finite element analysis software – is used to build the 3D model and a coupled thermal-mechanical simulation is performed in which the heat flux is determined by an empirical laser-heat conversion relationship. The displacement and stress field-histories are obtained to get the time of arrival and wave propagation speed of the stress wave. The effect of an added point mass is investigated in detail to observe the local material perturbation and remote wave signals. Following this, the experimental investigation of optoacoustic wave is also performed. A new experimental setup and control is developed and assembled in-house. Various laser firing parameters are investigated experimentally and the optimal combination is used for the experimental testing. Matrix design for different testing conditions is also proposed to include the effect of wave path, sampling procedure, and local point mass on the optoacoustic wave propagation. The developed numerical simulation results are validated with experimental observations. It is shown that the proposed experimental setup can offer a potential fast scanning method for damage detection (local property change) for plate-like structural component.

Contributors

Agent

Created

Date Created
  • 2016

156755-Thumbnail Image.png

Thermal Performance of PNIPAm as an Evaporative Cooling Medium within a Ventilated Wall Cavity

Description

Learning from the anatomy of leaves, a new approach to bio-inspired passive evaporative cooling is presented that utilizes the temperature-responsive properties of PNIPAm hydrogels. Specifically, an experimental evaporation rate from

Learning from the anatomy of leaves, a new approach to bio-inspired passive evaporative cooling is presented that utilizes the temperature-responsive properties of PNIPAm hydrogels. Specifically, an experimental evaporation rate from the polymer, PNIPAm, is determined within an environmental chamber, which is programmed to simulate temperature and humidity conditions common in Phoenix, Arizona in the summer. This evaporation rate is then used to determine the theoretical heat transfer through a layer of PNIPAm that is attached to an exterior wall of a building within a ventilated cavity in Phoenix. The evaporation of water to the air gap from the polymer layer absorbs heat that could otherwise be conducted to the interior space of the building and then dispels it as a vapor away from the building. The results indicate that the addition of the PNIPAm layer removes all heat radiated from the exterior cladding, indicating that it could significantly reduce the demand for air conditioning at the interior side of the wall to which it is attached.

Contributors

Agent

Created

Date Created
  • 2018

156726-Thumbnail Image.png

Beyond recycling: design for disassembly, reuse, and circular economy in the built environment

Description

Today, we use resources faster than they can be replaced. Construction consumes more resources than any other industry and has one of the largest waste streams. Resource consumption and waste

Today, we use resources faster than they can be replaced. Construction consumes more resources than any other industry and has one of the largest waste streams. Resource consumption and waste generation are expected to grow as the global population increases. The circular economy (CE) is based on the concept of a closed-loop cycle (CLC) and proposes a solution that, in theory, can eliminate the environmental impacts caused by construction and demolition (C&D) waste and increase the efficiency of resources’ use. In a CLC, building materials are reused, remanufactured, recycled, and reintegrated into other buildings (or into other sectors) without creating any waste.

Designing out waste is the core principle of the CE. Design for disassembly or design for deconstruction (DfD) is the practice of planning the future deconstruction of a building and the reuse of its materials. Concepts like DfD, CE, and product-service systems (PSS) can work together to promote CLC in the built environment. PSS are business models based on stewardship instead of ownership. CE combines DfD, PSS, materials’ durability, and materials’ reuse in multiple life cycles to promote a low-carbon, regenerative economy. CE prioritizes reuse over recycling. Dealing with resource scarcity demands us to think beyond the incremental changes from recycling waste; it demands an urgent, systemic, and radical change in the way we design, build, and procure construction materials.

This dissertation aims to answer three research questions: 1) How can researchers estimate the environmental benefits of reusing building components, 2) What variables are susceptible to affect the environmental impact assessment of reuse, and 3) What are the barriers and opportunities for DfD and materials’ reuse in the current design practice in the United States.

The first part of this study investigated how different life cycle assessment (LCA) methods (i.e., hybrid LCA and process-based LCA), assumptions (e.g., reuse rates, transportation distances, number of reuses), and LCA timelines can affect the results of a closed-loop LCA. The second part of this study built on interviews with architects in the United States to understand why DfD is not part of the current design practice in the country.

Contributors

Agent

Created

Date Created
  • 2018

152177-Thumbnail Image.png

Incorporation of phase change materials into cementitious systems

Description

Manufacture of building materials requires significant energy, and as demand for these materials continues to increase, the energy requirement will as well. Offsetting this energy use will require increased focus

Manufacture of building materials requires significant energy, and as demand for these materials continues to increase, the energy requirement will as well. Offsetting this energy use will require increased focus on sustainable building materials. Further, the energy used in building, particularly in heating and air conditioning, accounts for 40 percent of a buildings energy use. Increasing the efficiency of building materials will reduce energy usage over the life time of the building. Current methods for maintaining the interior environment can be highly inefficient depending on the building materials selected. Materials such as concrete have low thermal efficiency and have a low heat capacity meaning it provides little insulation. Use of phase change materials (PCM) provides the opportunity to increase environmental efficiency of buildings by using the inherent latent heat storage as well as the increased heat capacity. Incorporating PCM into concrete via lightweight aggregates (LWA) by direct addition is seen as a viable option for increasing the thermal storage capabilities of concrete, thereby increasing building energy efficiency. As PCM change phase from solid to liquid, heat is absorbed from the surroundings, decreasing the demand on the air conditioning systems on a hot day or vice versa on a cold day. Further these materials provide an additional insulating capacity above the value of plain concrete. When the temperature drops outside the PCM turns back into a solid and releases the energy stored from the day. PCM is a hydrophobic material and causes reductions in compressive strength when incorporated directly into concrete, as shown in previous studies. A proposed method for mitigating this detrimental effect, while still incorporating PCM into concrete is to encapsulate the PCM in aggregate. This technique would, in theory, allow for the use of phase change materials directly in concrete, increasing the thermal efficiency of buildings, while negating the negative effect on compressive strength of the material.

Contributors

Agent

Created

Date Created
  • 2013

151960-Thumbnail Image.png

Multiphysics design optimization model for structural walls incorporating phase change materials

Description

Buildings consume a large portion of the world's energy, but with the integration of phase change materials (PCMs) in building elements this energy cost can be greatly reduced. The addition

Buildings consume a large portion of the world's energy, but with the integration of phase change materials (PCMs) in building elements this energy cost can be greatly reduced. The addition of PCMs into building elements, however, becomes a challenge to model and analyze how the material actually affects the energy flow and temperatures in the system. This research work presents a comprehensive computer program used to model and analyze PCM embedded wall systems. The use of the finite element method (FEM) provides the tool to analyze the energy flow of these systems. Finite element analysis (FEA) can model the transient analysis of a typical climate cycle along with nonlinear problems, which the addition of PCM causes. The use of phase change materials is also a costly material expense. The initial expense of using PCMs can be compensated by the reduction in energy costs it can provide. Optimization is the tool used to determine the optimal point between adding PCM into a wall and the amount of energy savings that layer will provide. The integration of these two tools into a computer program allows for models to be efficiently created, analyzed and optimized. The program was then used to understand the benefits between two different wall models, a wall with a single layer of PCM or a wall with two different PCM layers. The effect of the PCMs on the inside wall temperature along with the energy flow across the wall are computed. The numerical results show that a multi-layer PCM wall was more energy efficient and cost effective than the single PCM layer wall. A structural analysis was then performed on the optimized designs using ABAQUS v. 6.10 to ensure the structural integrity of the wall was not affected by adding PCM layer(s).

Contributors

Agent

Created

Date Created
  • 2013