83 research outputs found
The effects of a lean transition on process times, patients and employees
No full textPurpose - Treatment delays must be avoided, especially in oncology, to assure sustainable high-quality health care and increase the odds of survival. The purpose of this paper is to hypothesize that waiting times would decrease and patients and employees would benefit, when specific lean interventions are incorporated in an organizational improvement approach. Design/methodology/approach - In 2013, 15 lean interventions were initiated to improve flow in a single radiotherapy institute. Process/waiting times, patient satisfaction, safety, employee satisfaction, and absenteeism were evaluated using a mixed methods methodology (2010-2014). Data from databases, surveys, and interviews were analyzed by time series analysis, chi(2), multi-level regression, and t-tests. Findings - Median waiting/process times improved from 20.2 days in 2012 to 16.3 days in 2014 (p Originality/value - Combining specific lean interventions with an organizational improvement approach improved waiting times, patient safety, employee satisfaction, and absenteeism on the short term. Continuing evaluation of effects should study the improvements sustainability
Tú que dices ser nuestro Dios: Reflexiones sobre imágenes de Dios en tiempos de crisis. Inspirado por textos de Huub Oosterhuis
No full textThe author explores God images that can be credible in times of crisis, through the translation and interpretation of three songs of the Dutch theologian and poet Huub Oosterhuis. Starting from the position of negative theology, the author presents a phenomenological study of the sorrows, longings and yearnings that resonate when people call on God in everyday life. She suggests contemplating God in the clamour for His absence, in positive experiences of contrast and in moments when light erupts in the darkness, when unexpectedly future possibilities open upLa autora explora imágenes de Dios que pueden ser creíbles en tiempos de crisis, mediante la traducción e interpretación crítica de tres canciones del teólogo y poeta holandés Huub Oosterhuis. Partiendo desde la teología negativa, el artículo explora una mirada fenomenológica a los gritos, suspiros y anhelos que resuenan cuando las personas llaman a Dios en la cotidianidad. Propone contemplar a Dios en el clamor por su ausencia, en experiencias de contraste positivas, y en momentos de irrupción de luz frente a la oscuridad, cuando inesperadamente se vislumbran posibilidades de futuro
Immunomodulation by diet : individual differences in sensitivity in layer hens
No full textEnhancing relevant immunity of production animals to achieve more robust animals is receiving more and more attention. Several epidemics have hit production animals recently and with devastating consequences, but enhancing diseases resistance increasingly provides new opportunities. Furthermore, welfare and health of production animals is becoming a more and more consumer driven topic. Several routes are being used to approach the possibility of enhancing immunity such as selective breeding, enriched and altered housing conditions, vaccination programs, diet supplementation with immune stimulating components, and other management procedures. Disease susceptibility has been shown to be related to stress reactivity, which in turn is related to differences in HPA axis reactivity. Interestingly, independent of selection criteria used, the extremes of various selection procedures result in a recurrent dichotomy in HPA axis reactivity, either being hyperresponsive or hyporesponsive to stress. Animals with a hyperresponsive HPA axis show greater environmental sensitivity, while the hyporeactive animals are more intrinsically regulated. Often, research on immunomodulation is performed with compromised animals and/or exaggerated supplementation of dietary components in one generation of animals, but epigenetics by definition seems to be the mechanism for mothers to prepare their offspring for the environment they will be born into. Enhancing immunity through normal diet in uncompromised animals is rarely investigated, let alone over generations. In this thesis the aim was to induce immunomodulation through diet in selection lines of chicken that have previously been selected on their antibody response to sheep red blood cells over two generations of chicken. First, potential HPA axis differences were examined in these selection lines to establish their environmental sensitivity, whereafter immunomodulation through normal diet was investigated in humoral and cellular parameters of immunity. As humoral immunocompentence was not easily modulated, an immune trigger was used to detect potential differences in humoral reactivity. The selection lines showed differential sensitivity to immunomodulation by diet in both generations, suggesting that adaptation to environmental factors may be a line-specific (genetically based) process, with differential neuroendocrine regulation. Most interestingly, the second generation showed effects of the diets in all the selection lines, albeit in different manners. It is concluded that normal diet can cause immunomodulation, mainly in animals with hyper HPA axis reactivity, and that introducing such practices may be more beneficial when mothers are treated, as all offspring showed immunomodulation, irrespective of selection line. While genetic background and/or epigenetic processes on neuroendocrine and immune regulation of the individual form the framework wherein individual immunomodulation by diet can take place, environmental conditions determine if the modulation is beneficial or not. <br/
Laser-beam welding as a method to characterise in-situ local thermo-mechanical conditions leading to liquid zinc embrittlement of Dual-Phase steel
No full textLiquid metal embrittlement (LME) is a problem encountered in the resistance spot welding joining process of advanced high-strength steels in the automotive industry. Its occurrence reduces the mechanical performance of welds. The nature of resistance spot welding prevents in-situ characterisation of thermo-mechanical conditions causing LME. Laser-beam welding (LBW) under tension is proposed as an alternative method to analyse LME cracks growing during the welding process of a DP1000 dual-phase steel grade. The influence of global thermo-mechanical parameters on the degree of embrittlement is investigated through Gleeble hot tensile tests. LBW schedules are explored, and material characterisation used to find and prove LME crack occurrence. Finite element analysis with COMSOL is used to connect results from Gleeble hot tensile tests with results from LBW and relevance to RSW is outlined. Results show that a temperature dependent ductility trough is present between 750 and 900°C. The Fe-Zn system is further found to require specific mechanical conditions (stress and strain rate) to become susceptible to LME. The proposed LBW setup is found to be susceptible to LME, but not in a high enough severity to be detectable through SEM and EDS. Changes should be made to the loading setup of the LBW setup to induce LME crack growth to a sufficient degree to allow for in-situ monitoring of local thermo-mechanical conditions surrounding the crack.Materials Science and Engineerin
Energiezuinige kantoorgebouwen: Een onderzoek naar het empirische bewijs van de bereidheid om te betalen voor energiezuinige kantoorgebouwen in de Randstad
No full textThis research concerns the economics of energy-efficient buildings: by merging auction theory and hedonic regression analyses, the price premium paid in the Netherlands for energy-efficient office buildings is investigated. The importance of the transition to an energy-efficient built environment is underlined by the increasing Dutch and European regulations regarding energy efficiency within the real estate market. As a result, the market for energy-efficient buildings has grown considerably in recent years. Therefore, office buildings increasingly have various voluntary and mandatory energy certificates. Since 2008, the energy label has been the measure of the energy performance of a building in the Netherlands and is therefore included as a test unit in this study.Problem analysis Most studies in this field have been conducted in the United States, primarily because CoStar has an extensive database of commercial real estate. As the Netherlands does not have such a centrally organized database, research into this subject is made more complex. Over the last couple of years, there has been growing interest in the financial performance of energy efficient buildings. However, the relatively large deviation and sometimes improbable contradictions of the identified price premiums in the various hedonic price studies might indicate that in some cases the models suffer from misspecification. It is possible that this results in an over- or underestimation of the rental price premium of energy efficiency in the Netherlands. This research presents a refined model to better isolate the effect of energy efficiency on the willingness-to-pay from the overall building quality, and therewith to determine the realistic rental premium for energy efficiency in the Dutch office market. Aim of the study This study aimed to determine the rental premium for energy efficient office buildings at the level of an office unit in the Randstad. An office unit is the office space that is included in a lease contract. In addition to the economic factors, location, and building characteristics, it was particularly important to include building and facade aesthetic features in the analysis, because such a control was missing in most comparable studies. It was expected that by controlling for aesthetic building and facade features, the rental premium for energy-efficient office buildings would be lower because the effect of energy efficiency on the rental price would be better isolated. Relevance Previous research in this field has shown that tenants are prepared to pay for energy-efficient office buildings. However, that research rarely controls for aesthetic building and facade features, which VII creates a gap in academic knowledge. By operationalizing and quantifying building and facade features, it is possible to control for these features. Therefore, the added academic value of this research is the more in-depth control of the aesthetic building and facade features. This research into the rental premium of energy-efficient office buildings in the Randstad contributes to the knowledge of stakeholders such as investors, developers, researchers, real estate agents, urban planners and policymakers. They need insight in the dynamics and influence of the energy efficiency of office buildings on the various office markets. This research offers the possibility of a practical application for the price characteristic as a benchmark within the valuation process. Methodology The aim of this research is to determine the rental premium of energy-efficient office buildings. The research wanted to give an accurate description of the actions that must be taken to achieve the goal of the research (Figure 2). Step 1 describes the reason and defines the problem statement by analysing the current context of the research field. Step 2 relates to the theoretical basis for regression analysis. Significant rental determinants within previous research have been identified to create a theoretical basis for the regression model. In step 3, data is collected for the multiple regression analysis and the mathematical specifications of the model are formulated. In step 4, the collected data is analysed and the regression model is formulated and designed. Different models are constructed and investigated. Step 5 concerns the interpretation of the model results. The re-evaluation and improvement of the content in an earlier phase resulted in an integrated design process in which the definitive regression model of this research was constructed. Results and conclusions The Research shows a positive rental premium for energy-efficient office buildings. The estimates of the predictive model indicate a rent price premium of 8.4% for energy efficient office buildings (label A-C) versus energy inefficient office buildings (label D-G). The research has also shown that different rental premiums are paid for different energy labels. The regression shows that when controlling for all other variables related to the macro, meso and micro levels, tenants are willing to pay substantially higher rents for office buildings with a B and or C label than for buildings with energy label A. Furthermore, tenants pay substantially lower rents for buildings with energy label E than for those with label A. No substantial differences have been demonstrated in the rent for the other energy labels. Perhaps, the lack of significance for buildings with a D, F or G label is the result of the small samples size in this research, so significant results are more difficult to achieve. In addition to the usual control of economic, location and building factors in rental premium research, this research has added a control level of building and facade aesthetic features. This control was missing in almost all comparable studies. If the control for aesthetic building and facade features is left out of consideration, the rental premium for energy-efficient office building would have been 13.5%, about 5% higher than the proven rent price premium of 8.4%. The addition of the level of control with regard to aesthetic building and facades features therefore has a significant effect on the rental price premium. This result was expected. The effect of energy efficiency on the rental price of office buildings is positive, but this is weaker than in previous studies because the effect of energy efficiency is better isolated through the extensive control of aesthetic building and facade features and was therefore determined more precisely.Architecture, Urbanism and Building Sciences | Management in the Built Environmen
QPack: A cross-platform quantum benchmark-suite: Quantitative performance metrics for application-oriented quantum computer benchmarking
No full textAs the technology of quantum computers improves, the need to evaluate their performance also becomes an important tool for indexing and comparing of quantum performance. Current benchmarking proposals either focus on gate-level evaluation, are centered around a single performance metric, or only evaluate in-house quantum computers. This gives rise to the need for a holistic, application- oriented, and hardware-agnostic benchmarking tool that can provide fair and varied insight into quantum computer performance. This thesis continues the development of the QPack benchmark, which collects quantum computer data by running noisy intermediate-scale quantum (NISQ)-era applications and transforms this data into an overall performance score, which is decomposed into four subscores.These scores are quantitative metrics of quantum performance that allow for easy and quick comparisons between different quantum computers. The QPack benchmark is an application-oriented cross-platform benchmarking suite for quantum computers and simulators, which makes use of scalable Quantum Approximate Optimization Algorithm and Variational Quantum Eigensolver applications. Using a varied set of benchmark applications, an insight into how well a quantum computer or its simulator performs on a general NISQ-era application can be quantitatively made. QPack is built on top of the cross-platform library |Lib⟩ (pronounced: libket), which allows for a single expression of a quantum circuit and execution on multiple quantum computers.Using the QPack benchmarking scores, a comparison is made between various quantum computer simulators, running both locally and on vendors’ remote cloud services. Tested local simulators include Qiskit Aer, Cirq, Rigetti QVM, and QuEST. For remote simulators, the IBMQ, IonQ, and Rigetti simulators have been benchmarked. The QPack benchmark is also executed on the Rigetti Aspen-M-1 and a selection of available quantum hardware from the IBMQ aviary, namely the Nairobi, Jakarta, Perth, Lagos, Quito, and Manila processors. For all quantum computers, an analysis is made of their individual performance in the QPack benchmark, as well as an evaluation of how these simulators or hardware implementations compare to each other. Based on the results of the QPack benchmark, the local QuEST simulator, the remote IBMQ QASM simulator and the IBMQ Nairobi and Quito quantum computers achieve best performance compared to the other tested backends.This work shows that the QPack benchmark is capable of providing holistic quantum computer performance for quantum computers, be it physical implementation or their simulator counterparts. The latest version of the QPack benchmark and all the results collected can be found in the repository: https://gitlab.com/libket/qpack/-/tree/stable.https://gitlab.com/libket/qpack/-/tree/stable Link to code repositor
Impact analysis of Capesize vessels on ArcelorMittal Ghent
No full textThe enlargement of the lock complex of Terneuzen in 2023 will allow Capesize vessels up to 300 meters in length, to access the Ghent-Terneuzen canal and reach the quay of ArcelorMittal Ghent (AMG). The goal of this thesis is to estimate to what extent these vessels can be used, the impact that these vessels will have on the supply chain and the cost impact of the implementation of Capesize vessels. The production of AMG is expected to be increased up to 5.5 million ton of steel for 2026. Therefore, it will require an estimated 12.9 million ton of raw materials (12% increase compared to 2019) which mainly consist of iron ore and coal. Up to 31% of this material can be shipped from source ports that are accessible by Capesize vessels. The draught restriction of 12.5 meters for the canal, limits the amount of bulk material that can be unloaded by the Capesize vessel to 105,000 DWT which is 60% of the maximum of 175,000 DWT. The remaining 70,000 tons of material can be unloaded externally and be transported to AMG by the use of inland barging vessels. The increased volume of Capesize vessels compared to the current Panamax vessels will lead to an increase in load size and a decrease in load frequency which will affect the downstream installations of AMG. Most of the current quay cranes will be unable to unload Capesize vessels due to the increased size of the ships. A proposed crane was introduced in the model to examine the ideal positioning to unload Capesize vessels and barges. 6 realistic scenarios for 2026 have been examined with varying levels of Capesize utilization. As a result of these scenarios vessel arrival lists for full year were simulated. Each of the vessel lists served as input data on a quay model with as results the downstream impact. The main output parameters were the waiting time for sea vessels, waiting time for barges and the amount of material that had to be stored on a temporary storage. In general, the implementation had a negative effect on all three of the output parameters resulting in additional quay costs. The net effect of Capesize vessels on the total costs was positive thanks to the lower shipping price per ton of material. This benefit was partly compensated by the increased costs for barging that was caused by Capesize transport. The shipping costs for Capesize vessels should at least be 2.53 dollar per ton cheaper, to break-even with Panamax vessels. Under current circumstances the full-scale use of Capesize vessels can be feasible. However due the high volatility of the dry bulk market and bunker prices, it is impossible to guarantee this will be the case for 2026.Applied Earth Science
Technical feasibility assessment for hydrogen transport through existing offshore gas pipelines in the Dutch sector
No full textIn the last century, the offshore industry has installed a network of offshore pipelines in the southern North Sea. Due to decreasing oil and gas extraction in the North Sea, many pipelines of this network are becoming redundant. A potential option for the reuse of these pipelines is the transport and storage of gaseous hydrogen, which is increasingly considered as an attractive energy carrier for a fossil fuel free economy. A Shell study has shown that offshore hydrogen production located at a renewable energy source, such as an offshore wind park, can economically compete with onshore hydrogen production that uses power cables to transport the energy to shore. The offshore hydrogen production case is based on newly built pipelines. If it is technically feasible to use existing pipelines, this can contribute to making the offshore hydrogen production case more attractive.A transition from hydrocarbon transport to hydrogen transport through existing carbon steel gas pipelines changes the material behaviour of the pipeline, including a change in fatigue behaviour. Fatigue damage due to Vortex-induced vibrations (VIV) in offshore pipeline parts that are suspended above the seabed is a major challenge for oil and gas transportation in the southern North Sea. Therefore, it is of great importance to understand the change in fatigue behaviour due to the presence of gaseous hydrogen to assess the technical feasibility of hydrogen transport through the existing offshore pipelines.A fatigue analysis for a specified existing gas pipeline of the NAM in the southern North Sea has been done according to DNV Free Spanning Assessment Methodology. For this analysis, the fatigue SN-curve for carbon steel material in a hydrogen environment is required. The SN-curve is approached based on available fatigue data for carbon steel material in hydrogen and severe sour environments. It shows that hydrogen has a significant influence on the fatigue behaviour of carbon steel material. The fatigue analysis outcomes show that adjustments to the pipeline are needed to avoid a significant increase in the risk of fatigue failure in critical pipeline sections. A remediation analysis has shown that rock dumping comes out as the cheapest option.An existing time-domain numerical model that can determine the dynamic behaviour of a pipeline due to VIV is extended to perform fatigue damage calculations. The pipeline is modelled as a Euler-Bernoulli beam using the Finite Element Method. The model determines the VIV with a modal analysis in time-domain, which allows the model to include non-linear soil behaviour. The fatigue damage is determined for each pipeline element, which gives the fatigue damage distribution over the length of the pipeline. The time-domain numerical model is compared with the DNV Free Spanning Assessment Methodology and gives significantly higher fatigue lives. This suggests that the methodology that is used for the fatigue analysis is too conservative. However, there is still uncertainty about the influence of parameters predicting VIV. Further calibration of the model is required to ensure that the model outcomes correspond with target failure probabilities regarding industry standards.The general conclusion of this research is that the specified existing offshore gas pipeline of the NAM is technically suitable for the transport of hydrogen if the adjustments are conducted. Compared to newly built pipelines, hydrogen transport through existing pipelines is an attractive option due to relatively low adjustments costs.Bottom Founded StructuresOffshore and Dredging Engineerin
Morphological modelling of the gravel revetment on artificial composite beaches
No full textThis thesis discusses the morphological modelling of the gravel revetment on artificial composite beaches. A composite beach is a combination of a sandy lower beach and a gravel upper beach. These beaches are found in nature, but can also be created artificially by placement of a gravel structure on a sandy beach. Artificial composite beaches are widely acknowledged as an effective type of shore protection against runup and overtopping (Blenkinsopp, 2016), but an assessment of such a beach with a numerical model has not been attempted yet.Therefore this work explores to what extent the morphological developments of these artificial beaches can be modelled with a numerical model. The numerical models that were used in this work are XBeach and XBeach-G. The aim is to reproduce the short term (3 to 6 hours) cross-shore morphological developments of the DynaRev experiments (a series of physical model experiments to investigate the stability of an artificial composite beach under sea-level rise), with a focus on the beach section on which the gravel revetment is placed. The first step was to find the relevant processes that are missing in the currently available numerical models. The missing processes were identified by combining knowledge acquired through the modelling of composite beaches with the currently available models, substantiated by analysis of the DynaRev experiments and literature research.It was concluded that the numerical models were lacking two important processes: namely the absence of a gravel transport formulation in XBeach and transport of sand in the gravel revetment. The missing processes were implemented into XBeach and the updatedmodel’s performances were verified with the DynaRev experiments as benchmark. The implementation of the XBeach-G gravel transport formulation in coherence with the existing XBeach code for sand transport required under-the-hood adaptations to improve the switches that are already in place for multiple sediment fractions. It was found that a combination of sand transport and gravel transport is possible, but this combination presents difficulties regarding suspended sediment transport in combination with the hydrodynamics and the groundwater dynamics.The second process was transport of sand in the gravel revetment. This was first analysed by looking at the initial transport rates of sand inside the revetment with a newly introduced equation for transport of sandinside a filter layer (Jacobsen et al., 2017). It was shown that transport fluxes of sand inside the revetment are likely to occur as results of the groundwater dynamics. To see bed level changes due to these transport fluxes this transport equation needs to be implemented into the XBeach code. This was not possible with the current architecture of XBeach and the way it accounts for multiple fractions. Therefore a new accounting system for multiple fractions was introduced in this work and implemented in XBeach, named the two-line model. In this experimental model sand transport gradients in the revetment are translated into visible sinking of the revetment (erosion) and settling of sand within the gravel revetment (deposition). In the model’s current state the erosive locations appear to match with the DynaRev observations, whereas locations where deposition occurs are no match. The two-line model was sensitive and showed instabilities, mainly due to high groundwater velocities that were caused by wave breaking in themodel. The results of the experimental model can possibly be improved by including vertical groundwater velocities to model sand transports, possibly also in combination with the addition of suspended sediment transport of sand inside the revetment.Civil Engineering | Hydraulic Engineering | Coastal Engineerin
Conceptual design of the Valmeer's pump storage station of the DELTA21 plan
No full textIt is widely known that climate change will cause sea level rise and larger river discharges in the close future (because more precipitation during a shorter amount of time will happen). In the Netherlands, the delta works were developed to protect the hinterland from sea-water during storm surge situations. The storm surge barriers close and the water is kept at the sea. However, if large river discharges are present together with storm surge, the water level behind the barriers will rise because the closed barrier won't let the river water out. In delta areas, this is a major threat to water safety. To tackle these future problems Huub Lavooij and Leen Berke came up with the DELTA21 plan. The plan is to build a storm surge barrier together with pumps that can evacuate the water from the river in the event of having both storm surge and large river discharges happening simultaneously. As this situation will happen once every ten years on average, there is a risk that the pumps might not function when needed if they were on hold for ten years. To tackle that problem and also producing green energy, a hydro pump storage basin is proposed to take advantage of the pumps already installed for flood protection. This hydro pump storage basin is called Valmeer. As this structure would be built next to the Maasvlakte 2, in a red Natura 2000 area, some ecological value must be gained with this project in return. That is why the Getijmeer (tidal lake) was created. This tidal lake would allow opening the Haringvliet sluices and thus recovering fish migration in that area. Bringing then the ecological, recreational and economic value to the Haringvliet area, which is currently closed to the sea. The objective of this thesis is to create a conceptual design of a hydro pump storage station able to turbine water in for energy generation and to pump it out for the same purpose and also for water safety. For designing the plant, three locations and three different alternatives were considered. Finally, a pump storage station that is also a storm surge barrier is proposed in the northern part of the DELTA21 plan, next to the Maasvlakte 2. Aspects such as constructability, affection of sediment transport to the plant, wave loading and access to the plant were taken into account for choosing the location and the most suitable alternative. The chosen alternative was found to be a good option if special care is taken about piping protection (the structure is subjected to head differences of 23 meters) and about methods to avoid water infiltration into the building pit during the construction of the plant (the building pit's floor is at NAP -32 m). As a part of the design, a life cycle analysis on CO2 emissions was performed. This showed that the hydro pump storage station can bring positive ecological value in terms of CO2 emissions reduction for the grid of the Netherlands. Producing energy at 280 g of CO2/kWh at present grid conditions and at -140 g of CO2/kWh if renewable energy is used to power the pumps. The conventional fossil fuel energy-producing methods do it at between 500 and 1050 g of CO2/kWh. Therefore this thesis shows that the DELTA21 plan is not only good for flood protection but for renewable energy generation. Contributing then to the United Nations Sustainable Development Goals of "affordable and clean energy" (energy generation function) and "life on land" (water safety function). DELTA21Civil Engineering | Hydraulic Engineerin
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