71 research outputs found
Three-dimensional deformation mapping of Mode I interlaminar crack extension in particle-toughened interlayers
No full textThis paper presents the first use of Digital Volume Correlation (DVC) on Carbon Fibre Reinforced Plastics (CFRPs) to quantify the strain fields ahead of a Mode I delamination. DVC is a relatively novel tool that can be used to measure displacements and strains occurring inside materials under load. In conjunction with Computed Tomography (CT), the technique has been applied to porous materials, with results providing strain data for validation of Finite Element (FE) models. However, the application of the technique to laminated materials has been limited, with studies often requiring fiducial markings required for volume correlation. In this work, crack propagation steps were captured at a 325 nm voxel resolution using Synchrotron Radiation Computed Tomography (SRCT). The material systems investigated featured different crack bridging mechanisms such as; particle-bridges, resin ligaments, and fibre-bridges. An assessment of noise and sub-volume size on the strain measurement determined that the optimal sub-volume size was 150 voxels with 50% overlap. This provided a spatial resolution of 48.8 ?m for strain and a corresponding strain resolution ranging between 220 and 690 ?? for the repeated reference scans. A rigid body translation study confirmed that specimen movements perpendicular to the fibre orientation support the ‘real’ physical displacements. However, along the fibre direction, the correlation was poor, with correct displacements being detected only within the particle-toughened interlayers. The study demonstrates that strain measurements can be made perpendicular to the fibre direction across the interlayer, which could be used to validate future FE models of these poorly understood particle-toughened interlayer
Crack path simulation in a particle-toughened interlayer within a polymer composite laminate
No full textWith recent advances in computational resources and the development of arbitrary cracking methods, such as the Augmented Finite Element Method (A-FEM), more complex simulations can now be represented featuring multiple interacting cracks. It has been established that Mode I crack propagation in particle-toughened interlayers within some toughened Carbon Fibre Reinforced Polymer (CFRP) laminates involves a discontinuous process zone, rather than a distinct crack tip. This results from multiple cracks forming ahead of the main crack that subsequently coalesce, leaving behind bridging ligaments that may then provide traction across the crack flanks. An idealised two-dimensional A-FEM model is presented in this work, which represents the ‘particles’ as one-dimensional cohesive regions. The model shows that variables such as particle spacing, distribution, strength and toughness, and fibre interface strength can be tailored in order to maintain the crack path within the interlayer. This competition between crack paths is important, as a reduction in composite toughness is reported when the crack path migrates to the fibre interface. The simulations are complemented by time-resolved Synchrotron Radiation Computed Tomography (SRCT) data, which identify the chronology of the damage processes, along with the effects of particle distribution on the crack path and the formation of bridging ligaments
Interlaminar fracture micro-mechanisms in toughened carbon fibre reinforced plastics investigated via synchrotron radiation computed tomography and laminography
No full textSynchrotron Radiation Computed Tomography (SRCT) and Synchrotron Radiation Computed Laminography (SRCL) permit 3D non-destructive evaluation of fracture micro-mechanisms at high spatial resolutions. Two types of particle-toughened Carbon Fibre Reinforced Polymer (CFRP) composites were loaded to allow crack growth in Modes I and II to be isolated and observed in standard and non-standard specimen geometries. Both materials failed in complex and distinct failure modes, showing that interlaminar fracture in these materials involves a process zone rather than a singular crack tip. The work indicates that incorporating particle/resin, fibre/interlayer and neat resin failure is essential within models for material response, since the competition between these mechanisms to provide the energetically favourable crack path influences the macro-scale toughness. The work uniquely combines the strengths of SRCT and SRCL to compare failure micro- mechanisms between two specimen geometries, whilst assessing any edge effects and providing powerful insight into the complex micro-mechanical behaviour of these materials
A randomized phase II study evaluating different maintenance schedules of nab-Paclitaxel in the first-line treatment of metastatic breast cancer: final results of the IBCSG 42-12/BIG 2-12 SNAP trial.
No full textpeer reviewedBackground: The phase II SNAP trial was designed to evaluate the efficacy of alternative chemotherapy schedules for prolonged administration in HER2-negative metastatic breast cancer (MBC), after a short induction at conventional doses. Methods: Between April 2013 and August 2015, 258 women untreated with chemotherapy for MBC were randomly assigned to receive three different maintenance chemotherapy schedules after three cycles of identical induction chemotherapy: Arm A, nab-Paclitaxel 150 mg/m2 days 1,15 Q28; Arm B, nab-Paclitaxel 100 mg/m2 days 1,8,15 Q28; Arm C, nab-Paclitaxel 75 mg/m2 days 1,8,15,22 Q28. Induction was three cycles nab-Paclitaxel 150/125 mg/m2, days 1,8,15 Q28. The primary objective was to evaluate the efficacy of each maintenance schedule, in terms of progression-free survival (PFS), as compared to the historical reference of 7-month median PFS reported by previous studies with first-line docetaxel. One-sample, one-sided log-rank tests were utilized. Quality-of-life evaluation was performed, global indicator for physical well-being was defined as the primary endpoint; completion rates of quality-of-life forms were >90%. Results: 255 patients were evaluable for the primary endpoint. After 18.2 months median follow-up, 182 PFS events were observed. Median PFS was 7.9 months (90%CI 6.8-8.4) in Arm A, 9.0 months (90%CI 8.1-10.9) in Arm B and 8.5 months (90%CI 6.7-9.5) in Arm C. PFS in Arm B was significantly longer than the historical reference of first-line docetaxel (P=0.03). Grade>/=2 sensory neuropathy was reported in 37.9%, 36.1% and 31.2% of patients in Arm A, Arm B and Arm C, respectively (Grade>/=3 in 9.1%, 5.6% and 6.6% of patients, respectively). Noteworthy, the quality-of-life scores for sensory neuropathy did not worsen with prolonged nab-Paclitaxel administration in any of the maintenance arms. Conclusion: The SNAP trial demonstrated that alternative nab-Paclitaxel maintenance schedules with reduced dosages after a short induction at conventional doses are feasible and active in the first-line treatment of MBC. Registration: ClinicalTrials.gov NCT01746225
Health Literature Hybrid AI for Health Improvement: A Design Analysis for Diabetes & Hypertension
No full textIncreasingly, front runner patients and practitioners want to use state-of-the-art science for rapid lifestyle based cure of diseases of affluence. However, the number of new health studies per year (>500.000) is overwhelming. How to quickly assess state-of-the-art and use new opportunities for rapid patient DIY (Do-It-Yourself) health improvement? In order to develop a health literature hybrid AI to aid DIY rapid health improvement, we analyze user side functional requirements. A cross case design analysis is conducted for hypertension and T2D (Type 2 Diabetes), two major cardiometabolic conditions in our society. Our analysis shows that current DIY health support is ‘watered down’ advise, prone to medicalizing rather than empowering patients. We propose hybrid AI user requirements and discuss how a 2030 hybrid AI health support system can stimulate new ways of working in health and cure.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Interactive Intelligenc
More than one way to solve the healthcare innovation crisis with digital platforms. Various forms of platform openness impacting primary healthcare
No full textWhereas open digital platforms drive innovation in industries, platforms in primary healthcare are mostly closed. Policy-makers have been looking for ways to open up primary healthcare platforms to stimulate collaboration and innovation and need to do so even more due to the ongoing COVID-19 crisis. Yet, there is not one way of opening up platforms in primary healthcare, just as it is unclear how different ways of openness can lead to more innovation. This paper analyzes the opportunities and challenges in realizing platform openness while examining alternative forms of openness. To answer this, we (1) conceptualize different forms of platform openness (sponsor-provider-platform-user openness), (2) examine how these forms of openness can resolve barriers to innovation, and (3) examine what challenges need to be overcome to realize that form of openness in practice, such as complexity in roles, regulations, and ICT infrastructure. The findings are relevant to structure further research on how platform openness leads to more innovations in healthcare.Information and Communication TechnologyEducation and Student AffairsEngineering, Systems and Service
Toward sovereign data exchange through a meta-platform for data marketplaces: A preliminary evaluation of the perceived efficacy of control mechanisms
No full textThe landscape of platform ecosystems is becoming increasingly complex, with new types of platforms emerging that glue together otherwise fragmented ecosystems. One recent case is metaplatforms that can contribute to the European Data Economy by interconnecting data marketplaces; however, meta-platforms may intensify data sovereignty concerns: the inability of data providers to own and control the exchanged data. While smart contracts and certification can generally enhance data sovereignty, it is unknown whether data providers perceive these control mechanisms as valuable in the complex meta-platform setting. This study aims to evaluate the perceived efficacy of the control mechanisms to ensure data sovereignty in meta-platforms. The findings from a survey study (n=93) indicate that respondents perceive high data sovereignty. One potential explanation is that smart contracts can potentially enable providers to maintain ownership and control over their exchanged data; meanwhile, certification may signal metaplatforms’ responsibility to deliver secure data exchange infrastructure and assist providers in adhering to relevant regulations. This study contributes to advancing design knowledge for meta-platforms, showcasing that meta-platforms can be designed in a way to resolve fragmentation without neglecting data sovereignty principles.Information and Communication Technolog
Does BMI help business to succeed?
No full textThis study investigates if BMI helps business innovation to succeed. We analyzed 27 SME cases having differing combinations of Business Model Innovation (BMI), New Product Development (NPD) and effectuation methods. We also analyzed the drivers and market strategy of the SMEs. We found out that typical SME innovation success cases combine at least two methods of implementation, such as BMI and NPD, and focus on low-end market. Effectuation in combination with the aforementioned seems to play significant role as well.Information and Communication Technolog
Control mechanisms for assessing the quality of handmade and artistic products in e-marketplace platforms
No full textSelling handmade and artistic goods online is challenging since buyers need to be able to assess product quality before purchase. This study aims to explore how control mechanisms aid the assessment of the product quality of handmade and artistic goods. We do so by extracting control mechanisms for e-marketplace platforms from existing literature and discussing to what extent these are suitable for handmade and artistic goods. We found that existing literature mainly focuses on reputation systems. We reshaped the findings by conducting desk research to identify how control mechanisms are applied in a number of e-marketplaces. Our results show that in e-marketplaces that focus on selling handmade artistic products, a reputation system is not sufficient to ensure product quality in an online environment. Thus, it is critical to apply other control mechanisms which are more effective in increasing the trustworthiness of the seller of artistic and handmade goods. Last, we also suggest alternative control mechanisms to be explored in future research.Information and Communication Technolog
Platformization of data sharing: Multi-party computation (MPC) as control mechanism and its effect on firms' participation in data sharing via data marketplaces
No full textData sharing facilitated by data marketplaces enable companies to generate meaningful insights and discover new opportunities. However, enterprises are reluctant to share data over platforms due to lack of trust, fear of losing control over data and concerns regarding privacy violations. Multi-party computation (MPC) is a cryptographic technique that enables joint data analyses by multiple parties while retaining data secrecy. Despite the potential of MPC, its meaning in data marketplaces setting and how MPC change firms' behavior towards data sharing is not yet researched. This research aims to explain why and how MPC could enable platform control and affect firms' participation in data sharing via data marketplaces. To do so, we will employ a mixed-method research design by combining semi-structured interviews with actors in the mobility domain and quantitative experiments using a mockup of MPC-enabled data marketplaces. Our initial findings revealed various barriers and incentives for firms in sharing their data. We expect our research to become a foundation for future research in the emerging phenomenon of platformization of data sharing via data marketplaces and the key role of MPC in enabling the data economy.Information and Communication Technolog
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