Beyond Digitizing

in Burrows, Simon; Roe, Glenn (Eds.) Digitizing Enlightenment: Digital Humanities and the Transformation of Eighteenth-century Studies (2020)

A Big Data Demand Estimation Model for Urban Congested Networks

in Transport and Telecommunication (2020)

Biomechanical properties of five different currently used implants for open-wedge high tibial osteotomy

in Journal of Experimental Orthopaedics (2015), 2(14),

Background: As several new tibial osteotomy plates recently appeared on the market, the aim of the present study was to compare mechanical static and fatigue strength of three newly designed plates with ... [more ▼]

Background: As several new tibial osteotomy plates recently appeared on the market, the aim of the present study was to compare mechanical static and fatigue strength of three newly designed plates with gold standard plates for the treatment of medial knee joint osteoarthritis. Methods: Sixteen fourth-generation tibial bone composites underwent a medial open-wedge high tibial osteotomyn(HTO) according to standard techniques, using five TomoFix standard plates, five PEEKPower plates and six iBalance implants. Static compression load to failure and load-controlled cyclic fatigue failure tests were performed. Forces, horizontal and vertical displacements were measured; rotational permanent plastic deformations, maximal displacement ranges in the hysteresis loops of the cyclic loading responses and dynamic stiffness were determined. Results: Static compression load to failure tests revealed that all plates showed sufficient stability up to 2400 N without any signs of opposite cortex fracture, which occurred above this load in all constructs at different load levels. During the fatigue failure tests, screw breakage in the iBalance group and opposite cortex fractures in all constructs occurred only under physiological loading conditions (<2400 N). The highest fatigue strength in terms of maximal load and number of cycles performed prior to failure was observed for the ContourLock group followed by the iBalance implants, the TomoFix standard (std) and small stature (sm) plates. The PEEKPower group showed the lowest fatigue strength. Conclusions: All plates showed sufficient stability under static loading. Compared to the TomoFix and the PEEKPower plates, the ContourLock plate and iBalance implant showed a higher mechanical fatigue strength during cyclic fatigue testing. These data suggest that both mechanical static and fatigue strength increase with a wider proximal T-shaped plate design together with diverging proximal screws as used in the ContourLock plate or a closed-wedge construction as in the iBalance design. Mechanical strength of the bone-implant constructs decreases with a narrow T-shaped proximal end design and converging proximal screws (TomoFix) or a short vertical plate design (PEEKPower Plate). Whenever high mechanical strength is required, a ContourLock or iBalance plate should be selected. [less ▲]

Biopharm - the Influence of Macro-substrates & Conditioning on Pharmaceutical Removal Rates by Moving Bed Biofilm Reactors

Doctoral thesis (2015)

Organic micropollutants with endocrine disruptive properties are present in the aquatic environment. A major part of their emission is caused by municipal wastewater treatment plants (WWTPs). For this ... [more ▼]

Organic micropollutants with endocrine disruptive properties are present in the aquatic environment. A major part of their emission is caused by municipal wastewater treatment plants (WWTPs). For this reason, a vast amount of research has been undertaken to remove xenobiotics from municipal wastewater by developing post-treatment technologies with some success. However, these technologies cause considerable environmental costs due their high demand for electrical energy implicating an increase in CO2 emissions. Consequently, existing biological treatments need first to be better understood and subsequently optimized regarding xenobiotic removal before post-treatments are employed. The study focused on the fate of xenobiotics during biological wastewater treatment. In particular, metabolic strategies of bacteria degrading pharmaceuticals were investigated within moving bed biofilm reactor (MBBR) processes. Two main objectives were tracked. On the one hand, it was to unfold the impact of macro-substrates in terms of type and molecular complexity on the activity of microorganisms and consequently pharmaceutical degradation performance. On the other hand, the study was set out to explore the adaptation of metabolic means regarding exoenzymes and consortia structure during continuous (long-term) exposure to pharmaceuticals. Accordingly, the ability to increase microbial competences during pharmaceutical short-term pulses was the general target of investigation. Both conditions continuous substance flow and short-term peak loads of xenobiotics are believed to occur in urban WWTPs. A pilot MBBR was set up next to a domestic WWTP. The pilot treated municipal sewage and served as inoculation reservoir for biofilm carriers used for in-depth laboratory experiments. The latter comprised six lab-scale MBBRs featuring flow through operation under controlled conditions regarding temperature, dissolved oxygen, pH, influent flow and influent load. The reactors were conditioned over four weeks with a synthetic sewage providing substrates and micro-nutrients in a similar manner as expected under real conditions. Biofilm was monitored by respirometry and a series of enzyme assays using fluorogenic substrates to capture esterase, phosphatase, alpha- and beta-glucosidase and aminopeptidase activity. All enzymes are essential during organic carbon metabolism. An array of macro-substrates with different molecular complexity was triggering individual enzyme activity profiles. After conditioning, 12 pharmaceuticals being subject to a range of anticipated metabolic pathways and degradation rates were spiked into the MBBRs. Their degradation kinetics were measured by liquid chromatography coupled with tandem mass spectrometry (LC MS/MS). Pseudo first-order kinetics revealed substrate related fingerprints and showed that readily biodegradable substrate leads generally to good pharmaceutical degradation performance compared to synthetic sewage with a mixture of several high molecular organic substrates. The latter was designed to induce the greatest metabolic effort of tested substrates before microbial uptake occurs. However, single substrates triggering exoenzyme activity in a more targeted manner such as maltose and cellobiose showed positive impact on the pseudo first-order rate coefficients of particular pharmaceuticals such as atenolol and diclofenac. Accordingly, alpha-glucosidase activity was found to be directly proportional to atenolol degradation kinetics. Phylogenetic characterisation of DNA and RNA involving state-of-the-art 16S ribosomal rRNA gene amplification and sequencing techniques was used to explore community structures. Prokaryote diversity in lab-scale MBBRs was in agreement to previous studies which investigated microbial consortia in full-scale systems. Multivariate analysis revealed that bacteria are adapting their active gene pool when the beta-blocker atenolol is continuously present with a concentration in ug/L range. Differential analysis unfolded that the prokaryotic genera Delftia and Lysobacter were thereby exclusively benefiting from the exposure to atenolol. Yet, compared to the influence of macro-substrates, biomass conditioning (training) with atenolol and diclofenac had no notable impact on the degradation performance of pharmaceutical short-term pulses. The outstanding comprehensive character of the study which encompassed sophisticated experimental design and powerful analytical tools from different scientific domains uncovered some interesting insights in xenobiotic degradation processes. The results finally show how biomass is reacting towards the presence of primary carbon sources and organic micro-pollutants. The outcomes highlight the importance of WWTP influent characterization being indicative of metabolic activity and therefore degradation capacity of xenobiotics. The study further suggests that xenobiotic metabolism and co-metabolism co-exist during biological treatment processes. Co-metabolism is the decisive actor when adaption time is relatively short as it was the case during the lab-scale experiments compared to real conditions. Further, the study indicates some potential of process enhancement of WWTPs ranging from straightforward implementations such as external carbon sources to more elaborated processes of bioaugmentation. [less ▲]

Blood flow simulation using smoothed particle hydrodynamics: application to thrombus generation

Scientific Conference (2016, March 31)

Blood flow rheology is considered to be a complex phenomenon. In order to understand the characteristics of blood flow, it is important to identify key parameters those influence the flow behaviour of ... [more ▼]

Blood flow rheology is considered to be a complex phenomenon. In order to understand the characteristics of blood flow, it is important to identify key parameters those influence the flow behaviour of blood. Further, the characterisation of blood flow will also enable us to understand flow parameters associated with physiological conditions such as atherosclerosis. Thrombosis plays a crucial role in atherosclerosis, or to stop bleeding when a blood vessel is injured. This article focuses on using meshless particle-based Lagrangian numerical technique named smoothed particles hydrodynamic (SPH) method to study the flow behaviour of blood and to explore flow condition that induces formation of thrombus in a blood vessel. Due its simplicity and effectiveness, the SPH method is employed here to simulate the process of thrombogenesis under the influence of various blood flow parameters. In the present SPH simulation, blood is modelled by particles that have characteristics of plasma and of platelets. To simulate coagulation of platelets which forms thrombus, the adhesion and aggregation process of platelets are modelled by an effective inter-particle force model. With these models, platelet motion in the flowing blood and platelet adhesion and aggregation are effectively coupled with viscous blood flow. In this study, the adhesion and aggregation of blood particles are performed on a bifurcated artery under a various low Reynolds number scenarios. The results are compared with experimental results and a good agreement is found between the simulated and experimental results. [less ▲]

Board Game Prototyping to Co-Design a Better Location-Based Digital Game

in Abstract book of the 2017 CHI Conference Extended Abstracts on Human Factors in Computing Systems - CHI EA '17 (2017)

In this case study we describe the iterative process of paper prototyping, using a board game, to co-design a location-based mobile application. The end goal of the application is to motivate reflection ... [more ▼]

In this case study we describe the iterative process of paper prototyping, using a board game, to co-design a location-based mobile application. The end goal of the application is to motivate reflection on historical topics about migration. The board game serves to capture the core concerns of this application by simulating movement through the city. Three play tests highlighted the users' interest and issues with the historical content, the way this content is represented, and the players' responses to the interactions and motivating mechanisms of the application. Results show that the board game helped capture important design preferences and problems, ensuring the improvement of our scenario. This feedback can help reduce development effort and implement a future technology prototype closer to the needs of our end users. [less ▲]

A Boolean Approach for Disentangling the Roles of Submodules to the Global Properties of a Biomodel

in Fundamenta Informaticae (2012), 116(1-4), 51-63

A boundary-enhanced supervoxel method for extraction of road edges in MLS point clouds

in A boundary-enhanced supervoxel method for extraction of road edges in MLS point clouds (2020)

Road extraction plays a significant role in production of high definition maps (HD maps). This paper presents a novel boundary-enhanced supervoxel segmentation method for extracting road edge contours ... [more ▼]

Road extraction plays a significant role in production of high definition maps (HD maps). This paper presents a novel boundary-enhanced supervoxel segmentation method for extracting road edge contours from MLS point clouds. The proposed method first leverages normal feature judgment to obtain 3D point clouds global geometric information, then clusters points according to an existing method with global geometric information to enhance the boundaries. Finally, it utilizes the neighbor spatial distance metric to extract the contours and drop out existing outliers. The proposed method is tested on two datasets acquired by a RIEGL VMX-450 MLS system that contain the major point cloud scenes with different types of road boundaries. The experimental results demonstrate that the proposed method provides a promising solution for extracting contours efficiently and completely. Results show that the precision values are 1.5 times higher and approximately equal than the other two existing methods when the recall value is 0 for both tested two road datasets. [less ▲]

Business analytics in manufacturing: Current trends, challenges and pathway to market leadership

in Operations Research Perspectives (2019)

Calibration of a microscopic simulation model for emission calculation

in Transportation Research. Part C : Emerging Technologies (2013), 31

Emissions by road traffic can be reduced by optimising traffic control. The impact of this optimisation on emission can be analysed ex ante by simulation. The simulation programs used for this analysis ... [more ▼]

Emissions by road traffic can be reduced by optimising traffic control. The impact of this optimisation on emission can be analysed ex ante by simulation. The simulation programs used for this analysis should be valid with respect to the traffic characteristics that determine the emissions. Thus calibration of the parameters is a prerequisite. In most cases, volumes, travel times and queues are used to calibrate simulation models, rather than detailed driving characteristics such as speed and acceleration patterns. However, these driving behaviour parameters determine the vehicular emissions to a great extent. A study was carried out in which the driving behaviour parameters in a microscopic simulation model (VISSIM) were calibrated using real trajectories collected by image processing at an intersection in Rotterdam. The sensitivity of the simulation results for driving behaviour parameters was investigated. The most influential parameters were identified and adjusted to ensure that the simulation results were consistent with the observed traffic and could provide valid estimations of the total production of emissions. [less ▲]