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- Cameron, Christopher John, 1980-
(författare)
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Design of Multifunctional Body Panels for Conflicting Structural and Acoustic Requirements in Automotive Applications
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Over the past century, the automobile has become an integral part of society, with vastincreases in safety, refinement, and complexity, but most unfortunately in mass. Thetrend of increasing mass cannot be maintained in the face of increasingly stringentregulations on fuel consumption and emissions.The body of work within this thesis exists to help the vehicle industry to take a stepforward in producing vehicles for the future in a sustainable manner in terms of botheconomic and ecological costs. In particular, the fundamentally conflicting requirementsof low weight and high stiffness in a structure which should have good acousticperformance is addressed.An iterative five step design method based on the concepts of multifunctionality andmultidisciplinary engineering is proposed to address the problem, and explained witha case study.In the first step of the process, the necessary functional requirements of the systemare evaluated. Focus is placed on the overall system behavior and diverted from subproblems.For the case study presented, the functional requirements included: structuralstiffness for various loading scenarios, mass efficiency, acoustic absorption, vibrationaldamping, protecting from the elements, durability of the external surfaces,and elements of styling.In the second step of the process, the performance requirements of the system wereestablished. This involved a thorough literature survey to establish the state of theart, a rigorous testing program, and an assessment of numerical models and tools toevaluate the performance metrics.In the third step of the process, a concept to fulfil requirements is proposed. Here, amulti-layered, multi-functional panel using composite materials, and polymer foamswith varying structural and acoustic properties was proposed.In the fourth step of the process, a method of refinement of the concept is proposed.Numerical tools and parameterized models were used to optimize the three dimensionaltopology of the panel,material properties, and dimensions of the layers in a stepwisemanner to simultaneously address the structural and acoustic performance.In the fifth and final step of the process, the final result and effectiveness of the methodused to achieve it is examined. Both the tools used and the final result in itself shouldbe examined. In the case study the process is repeated several times with increasingdegrees of complexity and success in achieving the overall design objectives.In addition to the design method, the concept of a multifunctional body panel is definedand developed and a considerable body of knowledge and understanding is presented.Variations in core topology, materials used, stacking sequence of layers, effects ofperforations, and air gaps within the structure are examined and their effects on performanceare explored and discussed. The concept shows promise in reducing vehicleweight while maintaining the structural and acoustic performance necessary in the contextof sustainable vehicle development.
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| 2. |
- Eckel-Passow, Jeanette, et al.
(författare)
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USING GERMLINE VARIANTS TO PREDICT GLIOMA RISK AND IDENTIFY GLIOMA SUBTYPE PRE-OPERATIVELY
- 2018
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Ingår i: Neuro-Oncology. - : OXFORD UNIV PRESS INC. - 1522-8517 .- 1523-5866. ; 20, s. 82-82
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- To date, 25 single nucleotide polymorphisms (SNPs) have been shown to be associated with overall glioma risk or with risk of specific subtypes of glioma. We hypothesized that the inclusion of these 25 SNPs with patient age at diagnosis and sex could predict risk of glioma as well as predict IDH mutation status. Thus, case-control design and multinomial logistic regression were used to develop models to estimate the risk of glioma development while accounting for molecular subtypes. Case-case design and logistic regression were used to develop models to predict IDH mutation status. Each model included all 25 glioma risk SNPs, patient age at diagnosis and sex. A total of 1273 glioma cases and 443 controls from Mayo Clinic were used in the discovery set, and 852 glioma cases and 231 controls from UCSF were used in the validation set. All samples were genotyped using a custom Illumina OncoArray. We observed that patients in the highest 5% of the risk score had more than a 14-fold increased relative risk of developing an IDH-mutant glioma, compared to patients with median risk score. Large differences in lifetime absolute risk were observed at the extremes of the risk score percentile categories. For both IDH-mutated 1p/19q non-codeleted glioma and IDH-mutated 1p/19q-codeleted glioma, the lifetime risk increased from almost null to 2.3% and almost null to 1.7%, respectively. The SNP-based model that predicted IDH mutation status had a validation c-index of 0.85. These results suggest that germline genotyping has the potential to provide a new tool for clinicians for the initial management of newly-discovered brain lesions. Specifically, given the low lifetime risk of glioma, SNP-based risk scores should not be useful for general population screening. However, with further research these risk scores may be useful in certain clinically-defined high-risk groups.
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