MR-based navigation for robot-assisted endovascular procedures

There is increasing interests in robotic and computer technologies to accurately perform endovascular intervention. One major limitation of current endovascular intervention—either manual or robot-assisted is the surgical navigation which still relies on 2D fluoroscopy. Recent research efforts are towards MRI-guided interventions to reduce ionizing radiation exposure, and to improve diagnosis, planning, navigation, and execution of endovascular interventions. We propose an MR-based navigation framework for robot-assisted endovascular procedures. The framework allows the acquisition of real-time MR images; segmentation of the vasculature and tracking of vascular instruments; and generation of MR-based guidance, both visual and haptic. The instrument tracking accuracy—a key aspect of the navigation framework—was assessed via 4 dedicated experiments with different acquisition settings, framerate, and time. The experiments showed clinically acceptable tracking accuracy in the range of 1.30–3.80 mm RMSE. We believe that this work represents a valuable first step towards MR-guided robot-assisted intervention

Dissolution and vaporization of superheated droplets and capsules

Intumescent coatings form a family of specialized paints used in modern architecture for fire protection. When exposed to heat, they greatly expand through bubble generation, i.e., intumesce, and subsequently act as a thermal barrier that delays structural collapse. Current intumescence technology relies on melamine as a chemical source of gas for bubble generation (blowing agent). However, melamine’s carcinogenic nature and its tendency to create uncontrolled bubbles limit the coating’s effectiveness and impacts both people’s health and the environment. It is therefore on the upcoming list of restricted substances. Fire protection technologies are thus in dire need of a new paradigm for bubble generation. Furthermore, a novel concept for bubble generation may prove invaluable to improve the coating’s mechanicalresistance and insulation properties, provided that it also allows control over the intumescence process. In this thesis, we explore the possibility of using physical means rather than chemical reactions to generate bubbles in coatings. More specifically, we aim at designing liquid precursors and exploiting controlled vaporization as a source of intumescence

Considerations on Approaches and Metrics in Automated Theorem Generation/Finding in Geometry

The pursue of what are properties that can be identified to permit an automated reasoning program to generate and find new and interesting theorems is an interesting research goal (pun intended). The automatic discovery of new theorems is a goal in itself, and it has been addressed in specific areas, with different methods. The separation of the "weeds", uninteresting, trivial facts, from the "wheat", new and interesting facts, is much harder, but is also being addressed by different authors using different approaches. In this paper we will focus on geometry. We present and discuss different approaches for the automatic discovery of geometric theorems (and properties), and different metrics to find the interesting theorems among all those that were generated. After this description we will introduce the first result of this article: An undecidability result proving that having an algorithmic procedure that decides for every possible Turing Machine that produces theorems, whether it is able to produce also interesting theorems, is an undecidable problem. Consequently, we will argue that judging whether a theorem prover is able to produce interesting theorems remains a non deterministic task, at best a task to be addressed by program based in an algorithm guided by heuristics criteria. Therefore, as a human, to satisfy this task two things are necessary: An expert survey that sheds light on what a theorem prover/finder of interesting geometric theorems is, and-to enable this analysis- other surveys that clarify metrics and approaches related to the interestingness of geometric theorems. In the conclusion of this article we will introduce the structure of two of these surveys -the second result of this article- and we will discuss some future work.</p

Production of Sustainable Aviation Fuel through Biomass:Experimental and Simulation approach

In this thesis, special attention is given to the influence of biomass characteristics and their uncertainties on the production of sustainable aviation fuel (SAF). As SAF mandates are being introduced to reach net-zero carbon emissions in the aviation sector, reliance on biomass feedstocks is growing; however, it comes with challenges and obstacles. Many pathways and configurations are being developed and scaled up to reach their full commercial potential. Resolving the challenges associated with biomass characterization will pave the way to the successful use of biomass in SAF production. Therefore, this thesis has two phases: an experimental and a simulation phase.Firstly, the experimental phase aims to improve the measurements of the biomass characteristics in the laboratory by performing a key comparison of the measurement techniques between different metrological institutes in the EU. The overarching goal of this phase was to lower the measurement uncertainty by improving repeatability and reproducibility. Eventually, new modifications to the ISO standards will be proposed. The improvement in the measurement accuracy directly impacts the values of purchasing and taxing biomass, as aspects like the energy and moisture content play a significant role in setting these values. Moreover, these improvements are expected to enhance biorefinery processes' design, performance, and yield.The second phase focuses on the impact of different types of biomass, their heterogeneity, and uncertainty on the production of SAF. Therefore, the various pathways of SAF production were comprehensively analyzed while considering technical and non-technical aspects to determine the most promising routes for producing SAF from biomass. Moreover, the analysis assessed the EU's biomass potential for SAF, focusing on its ability to meet proposed EU mandates for SAF uptake in the short and long term. After this analysis, several steady-state models for the Fischer Tropsch and Methanol to Jet were simulated in Aspen Plus commercial software. These models aimed to determine the influence of the experimentally determined biomass characteristics and their uncertainties on SAF production. Moreover, the models were used to determine the optimal and cost-effective pathway for SAF production through biomass. Different approaches, configurations, and tools were employed to achieve this objective, such as process simulation, sensitivity analysis, Monte Carlo simulation, and techno-economic analysis

Allocation optimization of two-stage compression-absorption heat exchanger

Space heating demand of buildings is a significant component of global energy consumption. Lowering the operating temperatures can increase the overall energetic and exergetic efficiencies. To obtain a lower return water temperature, researchers have proposed a variety of approaches. Absorption heat exchanger is an effective way to reduce return water temperature. However, in two-stage absorption heat exchanger and compression-absorption heat exchanger, extra temperature difference exists in evaporator of absorption heat pump. To eliminate the extra temperature difference, optimized compression-absorption heat exchanger is put forward in the article. Based on the typical case, the energy saving rate of optimized compression-absorption heat exchanger can reach 17.9 %, and the principle of energy saving is analyzed in the article, the key point is the extra temperature difference and the cooling capacity of evaporator of absorption heat pump. Further, the energy savings of the optimized heat changer in different supply and return temperature of primary and secondary network is analyzed. Main factors affecting the energy saving rate are primary network supply temperature and secondary network supply-return temperature difference. As the result, when primary network supply temperature is 130 ◦C and secondary network supply and return temperature is 50 ◦C and 40 ◦C, energy saving rate can reach 28.4 %

Care transformation defined by conditions, mechanisms, and outcomes: a systematic literature review

AbstractBackgroundQuality of care is under pressure due to demographic changes (shifting age of the population), epidemiological trends (more chronic diseases) and changes in the external environment (rapid development of technological innovations). Transformation in care is essential to deal with these changes. However, there is no consensus in the literature regarding the definition and factors contributing to care transformation.MethodsThis systematic review systematically searched the scientific databases Scopus, Web of Science and Pubmed until 22 January 2022. We included articles that focused on care transformation from a complex setting and multi-level perspective, with an empirical or theoretical rationale and methodology. Relevant data regarding the interconnection between contextual conditions, mechanism of change and outcomes were analysed using deductive coding. The generic contextual conditions-mechanisms outcome structure (CMO) [54]Pawson &amp; Tilly, 1997) was used as a framework to synthesise the results.ResultsNineteen articles were included. All related articles explain transformation from a complex systems perspective. Four of the 19 articles gave a definition of care transformation. These definitions of care transformation have the following in common: It involves radical and far-reaching change at an organisational and system-wide level, with the aim of improving performance, behaviour, efficiency, and quality of care, both at individual and population level. Relevant contextual conditions were the changing environment, organisational conditions, collaboration, direction of change and sources of funding. Relevant mechanisms for change were collaboration, leadership, interpersonal relationships, engagement, information technology and coordination. The key outcomes of care transformation are Integration of care, patient-centred care, and improvement of quality of care.ConclusionsAn important goal of care transformation is to deliver better quality of care and enable care integration. This study showed that effective collaboration among healthcare providers, supported by transformational leadership, strong interpersonal relationships, and coordination from multiple perspectives, play an important role in facilitating care transformation. Collaboration is an important mechanism for achieving the key outcomes of care transformation. Keywords: transformation, complex systems, collaboration, multi-level perspective, Quality of Healthcare<br/

Exploring the support needs of young adult caregivers, their issues, and preferences towards a web-based tool: a mixed-method study

BackgroundYoung adult caregivers (YACs, aged 18–25) who take care of a loved one may juggle between caregiving responsibilities and other life areas such as education and social life, leading to an imbalance in their lives. The web-based tool ‘MantelzorgBalans’ aims to support informal caregivers (ICGs) in balancing caregiving tasks and activities in other life areas. However, this tool was designed to support ICGs of loved ones receiving palliative care and is not yet tailored to the needs of YACs. In order to do so, in this study we aim to explore (i) challenges and support needs of YACs in caregiving, (ii) their needs towards the content of the ‘MantelzorgBalans’ tool, and (iii) issues they encountered in using the tool and their preferences for adaptation of the tool.MethodWe conducted semi-structured interviews and usability testing with 13 student YACs in the Netherlands. Within usability testing, we used three approaches: (i) a thinking-aloud approach (verbalizing thoughts while using the tool), (ii) a task-based performance approach (scoring task completion rate), and (iii) questionnaires. We used thematic analysis to synthesize the qualitative data. For the quantitative data, we calculated frequencies and mean scores.ResultsOur findings suggest that the majority of YACs faced challenges in balancing caregiving with life areas such as education and social life. They needed support from healthcare professionals who could listen to them without judging them. With respect to the MantelzorgBalans tool, YACs needed more information on how to provide emotional support to their loved one and the emotional support that is available for them. In regards to the aesthetics, they preferred bright colours and more visuals in the tool. Overall, they were satisfied with the information presented in the tool, but they were neutral in their willingness to use it in the future.ConclusionFrom this study, we learn that YACs may experience specific challenges and needs in general, and towards a web-based tool in specific. In the near future, it will be important to develop digital tools to support YACs that match their specific needs. This may enable healthcare professionals to offer targeted and personalized digital support to YACs in future

Investigating change of discomfort during repetitive force exertion though an exoskeleton cuff

This article investigates discomfort development for forces exerted repetitively and for extended durations through a rigid cuff. Three force patterns, chosen to mimic exoskeleton use, were applied to the thigh of 15 healthy participants for 30 min. Changes in perceived comfort and skin effects were recorded. Discomfort was detected at normal forces ranging from 40 to &gt;230 N. Repetitive force application triggered discomfort after a median of 4.1 min (normal force only) and 5.4 min (normal and shear force) respectively. Discomfort increased over time but the repetitive force applications did generally not result in pain and there were no significant differences between repetitive loading patterns. Exoskeleton design and use should be informed by comfort thresholds specific to prolonged repetitive loading. Large interindividual differences in perception of discomfort limit the possibilities for generally applicable comfort thresholds. Further research is needed to investigate how patient groups perceive such repetitive loading.</p

Supply and demand of ecosystem services of urban green spaces in deprived areas:Perceptions from Kumasi, Ghana

Urban green spaces (UGS) contribute to human health and wellbeing. However, few studies have focused on cities in the Global South, mainly examining them on a citywide scale without considering deprived areas where residents lack basic facilities and sufficient income. Consequently, there is limited understanding of the relationship between the availability of UGS and associated ecosystem services (ES), and what is actually demanded for by residents in such deprived areas. Therefore, this study aims to assess (i) the perceived supply and (ii) the perceived demand for ES of UGS in selected deprived urban areas; and (iii) to determine the potential gap(s) between these perceived supply and demand aspects. A mixed-method approach was adopted for the study, incorporating GIS methods, household surveys, and key informant interviews. As case studies, the study was conducted in two deprived areas in Kumasi, Ghana – Dakodwom and Ayigya Zongo. The findings reveal that land scarcity and encroachment have led to a limited supply of UGS in these areas. Nevertheless, residents appreciate the few available UGS and ES, demonstrating adaptation to their limited resources. They particularly highlighted the cultural ES provided by these UGS. The high demand for these services, surpassing their supply, shows significant gaps, emphasising the need for comprehensive urban planning and management decisions. Such decisions should involve all stakeholders and be underpinned by effective legislative support.</p

Stochastic array antenna figures-of-merit for quality-of-service-enhanced massive MIMO

This paper shows that the signal-to-interference-plus-noise ratio (SINR) at a base station (BS) equipped with an arbitrary physical array antenna can be expressed as a function of two fundamental, stochastic figure of merits (FoMs): (I) the instantaneous effective gain (IEG) and (II) the beamforming-channel correlation (BCC). This result is achieved by applying a novel channel normalization approach using a reference array to preserve effects induced by the embedded element patterns of physical antenna elements. It is shown that both FoMs provide essential insights for quality-of-service (QoS)-based array antenna design by investigating their statistics for BSs applying full-digital (FD) zero forcing (ZF) beamforming. Various array designs are evaluated, and it is shown that arrays with higher IEGs and a reduced probability of low BCCs can increase the ergodic sum rate and reduce the need for scheduling.</p