Flow Dynamics in Cardiovascular Devices: A Comprehensive Review

This review explores flow dynamics in cardiovascular devices, focusing on fundamental fluid mechanics principles and normal blood flow patterns. It discusses the role of different structures in maintaining flow dynamics and the importance of stents, heart valves, artificial hearts, and ventricular assist devices in cardiovascular interventions. The review emphasizes the need for optimized designs and further research to enhance knowledge of flow dynamics in cardiovascular devices, advancing the field and improving patient care in cardiovascular interventions

Mathematical modelling of gas flow networks in pellet induratlon systems

The objective of this research is to develop a simulation software tool, GASFLO, which should evaluate pressure, flow and temperature distributions of process gas in pellet induration system networks. Pellet induration systems are complex industrial systems composed of heterogenous components. The magnitude of gas through leaks i.e. the air entering or leaving the system from the points other than the known exits, is substantial and it adversely effects the performance of induration process. These leaks are very difficult to measure because of the hostile environment in the plant. The modelling of such industrial systems requires a notable amount of experimentation so the tool has been designed to enable the user modeller to change the component models and solution algorithms easily. The conventional methods for flow network simulation are based on process centred approach, mostly composed of homogeneous components. For ease of computation, the non-pipe elements are modelled with an approximate linear or non-linear generic equation, whose coefficients can simulate different states of the element. The resulting set of non-linear equations is linearised and solved simultaneously using some iterative method. By contrast, GASFLO is based on device centred or unit based approach, and uses a two level hierarchical solution algorithm. The pellet induration system network is first idealised into a connected graph of streams (sets of serially connected components) and nodes. At the top or coordination level the flow and pressure distributions satisfying the Kirchhoff's laws are evaluated for the connected graph. At the lower or component level the exact mathematical models of components ale computed, in order of their occurrence in respective streams, using coordination variables as parameters. The converged flows are used for the temperature computation. The solution algorithm requires partitioning of the connected graph into forest and coforest structures, for which secondary algorithms have been developed using specific heuristics relevant to the pellet induration systems. The rigorous application of software engineering techniques for the design and implementation of software, enabled the resolution of the complexity of the modelled system, embedded the characteristics of 'quality software' into the resulting code and benefits from object orientation, even though it is implemented in standard FORTRAN 77. GASFLO predicted results are in a good agreement with the measured results, it has been validated for a real life pellet induration system. It has been applied to simulate several practical scenarios, like addition of extra wind boxes to the zones and to determine how the plant production can be increased by certain ratio, such simulations were not feasible otherwise. GASFLO takes less than a minute to simulate a real-life pellet induration system on a 486 PC. The combined simulation with an other software tool, INDSYS, which evaluates the heat distribution in the solids, is also feasible

The Performance of Biomimicry Architecture in Sustainable Design for a Mixed-Use Workplace in Shanghai (Sustainable Design)

Abstract Sustainable architecture design is becoming more and more popular all over the world, especially in China. Active sustainable strategies play an important role in sustainable architecture design such as solar panels, wind turbines, and roof gardens. However, this Thesis will find some new passive ways to improve the sustainability of buildings by proving bionic technology. The thesis seeks to integrate living organisms into buildings to improve the sustainability of buildings and generate sustainable resources. This main focus is biomimetics. The technology used in the design of architecture sustainability. Bionics or biomimicry refers to artificial processes or systems that mimic nature. The thesis will develop a program that is about how to interpret biomimicry language to architecture language and apply it to the design of a building to improve its performance. The thesis finally mainly use three biomimicry technology to design the building. They are respectively (1) a termite mound structure to advance ventilation of the building, (2)algae to clean carbon dioxide, and (3) a three-leaf clover floor plan layout and building form. to create more fresh energy for the building. In addition, the thesis aims to use more biomimicry solutions to overcome those problems from site analysis

Numerical Simulations of Turbulent Flow through Piping Systems

Piping systems have a wide range of applications across many different industries. Pipelines are essential infrastructure in the offshore oil & gas installations. One of the key challenges when operating complicated piping systems is accurate measurement of the flow characteristics required for example to optimize the process or maintain the flow assurance. The pipe fittings such as elbows, bends, and reducers introduce disturbance in the flow and distort the velocity profile downstream in the pipe which adversely affects the accuracy of flowmeter devices. To counteract these undesired effects, various types of flow conditioners can be installed between the source of flow disturbance and the measuring device. In this thesis, the behavior of turbulent flow passing through three different components of the piping systems is investigated: an orifice plate, a 90-degree pipe bend and thereafter a honeycomb straightener. The Reynolds numbers in present analyses range from 1×104 to ≤ 2×105. First, a validation study of eight different Reynolds-Averaged Navier–Stokes (RANS) turbulence models is performed to choose the model that gives the best prediction of the fluid flow through an orifice flowmeter. Among the benchmarked models, the Explicit Algebraic Reynolds Stress Model (EARSM) shows the best agreement with the experimental validation data. In the second part, the validated turbulence model is used to study the effects of different pipe bend geometries and Reynolds number (Re) on the flow behavior. Based on further numerical simulations of the flow through the pipe bend, it is found that for small curvature radiuses (Rc/D<\ 2), the velocity profiles are highly deformed and separation bubble develops behind the bend. Finally, the influence of a new honeycomb straightener design on the flow quality is investigated downstream of the 90-degree pipe bend. The case of pipe bend with Rc/D=2 is employed to that end. It is concluded that the optimum effectiveness in eliminating the swirl and improving the velocity profile pattern is reached for the honeycomb straightener located at the minimum distance from the bend outlet of Lb=5 and thickness of t=0.5. Furthermore, a detail description of the investigated flow fields are presented in terms of axial velocity profiles, turbulence intensity, velocity perturbation, pressure, vortex formations, secondary flow regions, streamline patterns and swirl intensity

Design of a control system for an indirect solar dryer

Mestrado de dupla diplomação com a Université Libre de TunisThis dissertation focus on the control system design of a for indirect solar dryer without any difficulty of utilization with low cost and autonomous. The intended interest group of this model is small farmers who don't have the cash-flow to put resources into new drying innovations however need basic and modest machines to contend in the current market for nuts. In the present work, a multivariable control system using DHT22, BMP280 sensors to measure the drying process parameters of the fig. The Bernoulli equation was established in the Arduino program to calculate the air velocity. The valves designed based on servo motor DS3225. Then, the control of the position of the valve based on the measured sensor parameters and the conditions of the drying process. And for sending the data in real-time to the farmers, the IoT technology was used by the combination of the GSM/GRPS module with the Arduino UNO board. Then, the Blynk application was used to visualize the data, and the ThingSpeak IoT platform for saving the data and analyses the quality of the drying prosses. More than visualization the data in the Blynk application, a notification was added for the farmers in the case of start drying process and overheating condition. According to the outcomes of the Proteus simulation which have been shown by the Blynk application and the ThingSpeak IoT platform, it can conclude that the design of the control system is successfully done.Cette thèse porte sur la conception d'un système de contrôle pour séchoir solaire indirect sans aucune difficulté d'utilisation à faible coût et autonome. Le groupe d'intérêt visé par ce modèle est constitué de petits agriculteurs qui n'ont pas les liquidités nécessaires pour investir des ressources dans de nouvelles innovations de séchage, mais qui ont besoin de machines basiques et modestes pour lutter sur le marché actuel des noix. Dans le présent travail, un système de contrôle à plusieurs variables utilisant des capteurs DHT22, BMP280 pour mesurer les paramètres du processus de séchage de la fig. L'équation de Bernoulli a été établie dans le programme Arduino pour calculer la vitesse de l'air. Les vannes conçues sur la base d'un servomoteur DS3225. Ensuite, le contrôle de la position de la vanne en fonction des paramètres mesurés du capteur et des conditions du processus de séchage. Et pour envoyer les données en temps réel aux agriculteurs, la technologie IoT a été utilisée par la combinaison du module GSM / GRPS avec la carte Arduino UNO. Ensuite, l'application Blynk a été utilisée pour visualiser les données, et la plate-forme ThingSpeak IoT pour enregistrer les données et analyser la qualité du processus de séchage. Plus que la visualisation des données dans l'application Blynk, une notification a été ajoutée pour les agriculteurs en cas de démarrage du processus de séchage et de surchauffe. Selon les résultats de la simulation Proteus qui ont été montrés par l'application Blynk et la plate-forme ThingSpeak IoT, il peut conclure que la conception du système de contrôle est réussie

Simulating Realistic Social and Individual Behavior in Agent Societies

While the value of simulations as a tool in the natural sciences has been realized for quite some time, its potential in the social sciences is only beginning to be explored. A class of simulations used to study social behavior and phenomena is known as social simulations. One particular type of social simulation is known as agent based social simulation. Here agents are used to model social entities such as people, groups and towns. A purpose of these models is to reproduce realistic behavior in the simulation which is then used to draw conclusions about the corresponding real world entities. However reproducing realistic behavior is a difficult task. This is in part due to the fact that human actions and interactions do not adhere to well defined rules. A successful solution to this problem must reproduce realistic individual decision making as well as realistic social interactions. We propose two models. First, a model for producing realistic decision making is based off human intuition and deliberation. This model is tested in the Iterative Ultimatum Game and Bargaining Game. It is shown that when agents use both intuitive and deliberative decision making they make decisions similar to those of human subjects. Next we propose a realistic model for social interactions. Our agents remain selfish and are able to break relationships in order to maximize their utility. It is shown that when agents are able to break unrewarding relationships that a Pareto‐optimum strategy arises as the social convention. In addition we conclude the rate and amount of Pareto‐optimum strategy that arises is dependent on the network structure when the networks are dynamic and the rate is independent of the network structure when the networks are static

The Infusion Length of Material Filled Inside Hollow Core Fiber

We have designed a MATLAB code to perform the simulations on the infusion length of fluid inside the capillary. Previous research work has shown few results but the equation used for plotting the graph of infusion length v/s time has a numerical error. The work we have done has shown the step-by-step procedure to derive the list of forces acting on the capillary getting filled with the material and has also plotted the graph of infusion length v/s time from the equation we get after proof of derivation. The significant changes can be seen in the overall infusion length from the previous work and the work we have presented with mathematical derivations. The impact of overhead pressure, as well as capillary pressure on the infusion length, has been specifically discussed and the impact of the absence of one or the other could be clearly seen from the plots. The MATLAB simulation environment has been designed to go with any material to calculate the infusion length of the material over the time. List of factors affecting the filling length and calculation for same are presented in this report. The capillaries of hollow core fiber have been considered for the design looking at the applications of the fiber and future work

Preventing Atmospheric Icing in Aviation: Passive Repulsion of Super Cooled Water Droplets through Hydrophobic Nanocomposites

The aviation industry already consists of a complex system of strict regulations related to operation and maintenance, where severe weather conditions further challenge flight operations. Recent research has shown that most aircraft accidents are caused by icing externally, where severe icing conditions lead to the critical degradation of the aerodynamic effectiveness – increasing the stall speed. If only a thin film of ice accumulates on the airframe, it will rapidly increase the risk for a fatal accident to occur. The following thesis addresses critical icing conditions that might substantially affect the aerodynamic performance and propose an accessible method of a hydrophobic coating to mitigate the risk of ice accretion on planes. The results show that the most exposed phase within in-flight icing occurs at cruising altitude, with glaze ice accretions. A risk assessment of components suggests that the wing part has the most significant effect on aerodynamic sustainability. A further CFD analysis of the wing section of an Airbus A320neo, at cruising altitude, was simulated and compared with and without glaze ice conditions. The ice formation led to a mass of 2.3 kg after 100 seconds, while measurements determined that the drag capacity was increased significantly. The lifting capacity was virtually unaffected. Furthermore, a feasibility study has been conducted with the underlying goal of identifying the most promising of anti-icing coatings for aircraft. To date, there are no coat-ings capable of independently functioning as a passive anti-icing system. However, findings reveal two promising methods that were further carried out for testing. The preparation of a highly hydrophobic and ice phobic coating based on Zinc Stearate (ZnSt) and a curable Polydimethylsiloxane (PDMS) was carried out. Indicatively, the coating showed high water repellent and ice repellent properties by measuring the ice adhesion, which reduced the interaction between the aluminum surface and freezing water droplets by over 50%

Leakage and atmospheric dispersion of CO2 associated with carbon capture and storage projects

Climate change is affecting planet Earth. The main cause is anthropogenic emissions of greenhouse gases, the principal one being carbon dioxide, released in the atmosphere as a by-product of the combustion of hydrocarbons for the generation of energy. Carbon capture and storage (CCS) is a technology that would prevent carbon dioxide from being emitted into the atmosphere by safely sequestering it underground. For so doing, CO2 must be captured at large emission points and transported at high pressure to underground reservoirs, where the gas can be injected and stored for thousands of years to come. During surface transportation, leakages from high pressure facilities would pose a risk to the general public, for carbon dioxide is toxic at high concentrations. In this study, atmospheric dispersion of carbon dioxide is studied by the usage of software that solves mathematical equations and algorithms simulating the pollutant dispersion. Dispersion models are used to estimate or predict downwind distances covered by toxic concentrations of the pollutant, emitted from sources such as high-pressure transportation facilities within CCS projects. Two modelling tools from two different classes (Gaussian ALOHA 5.4 and Computational Fluid Dynamics PANACHE 3.4.1) have been evaluated against release field experiments using the statistical model evaluation method proposed by Hanna et al. (1993,2004) and Hanna and Chang (2001), and applied for the consideration of the dense gas CO2, released in large amounts due to leakages. Predictions from the two models have been compared and the limitations of both examined, when dealing with a gas that presents the distinctive physical characteristics of carbon dioxide. The models have been used and compared in simulating representative failure cases within CCS transportation with release parameters taken from the literature. The Computational Fluid Dynamics (CFD) model showed a much higher precision when describing the release of the gas from a HP facility, mainly when dealing with the jet release caused by leakages of any dimensions. When dealing with the transportation of toxic gases, the magnitude of hazards posed by potential failure events within the transportation system is proportional to the extent of the area covered by toxic concentrations of the gas, when modelling representative leakages. Results of this investigation depict a lowering of the Risk involved in the transportation of CO2 by up to an order of magnitude, when modelling the same releases with CFD tools, instead of the more common Gaussian models. The European Union recognizes that deployment of CCS for hydrocarbon power generation, in parallel with the production of renewable energies, is the only way to meet the target for temperature stabilization. For its Impact Assessment on CCS, the EU used results from a risk assessment compiled after the utilization of a Gaussian model. In this thesis, a criticism of this choice is put forward, considering that, when introducing the technology to the general public and regional scale administrators, a Risk Assessment derived using results from Gaussian models can over-estimate the risk in a way not favourable to the purpose

Space Sciences Division

Spacecraft instrumentation, biological sampling of Martian soil, Jupiter red spot data and solar wind variations, dielectric function of cold electron gas, and microwave spectra of ion radica