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1
Westaby, Stephen. "Towards a realistic artificial heart." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248952.
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Mahmood, Amar Kays. "Optimisation of sealing and bearing technologies in rotary blood pumps." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400287.
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Bludszuweit, Catrin. "A theoretical approach to the prediction of haemolysis in centrifugal blood pumps." Thesis, University of Strathclyde, 1994. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21317.
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The successful use of centrifugal pumps as temporary cardiac assist devices strongly depends on the extent to which they damage blood. The development of a theoretical pump evaluation model was performed in this study to facilitate an effective pump optimisation. The optimisation process seeks to maximise flow performance and minimise blood trauma which is primarily caused by hydrodynamic stresses. A general mechanical blood damage theory was developed which comprises a combination of the information about mechanical loading of blood with the knowledge of its resistance properties. In this theory arbitrary loading-time functions are reduced to simple loading functions for which the damage behaviour is known. A linear damage accumulation theory contributes towards the determination of partial damages and their correlation in the overall damage process. The application of this novel blood damage prediction theory was demonstrated for haemolysis prediction in a commercial centrifugal blood pump. Particle loading-time functions were determined with a 3-dimensional numerical flow analysis of the entire pump domain by means of assigning scalar stress values to particle streaklines. Scalar stress values were obtained by a theory which enables the comparison of a six-component stress tensor with uniaxial stresses as applied in blood damage tests. It was shown that particles undergo a complex, irregularly fluctuating stress loading and that turbulent stresses and flow conditions in the outlet domain are the most critical factors. Haemolysis tests using an oscillating capillary tube setup were performed to investigate blood damage resistance properties under cyclic stress loading in hitherto unexplored amplitude and frequency ranges. A non-linear damage curve for stress amplitude-cycle number was derived which indicated the existence of an endurance strength for red blood cells. For the first time, detailed information about the mechanical loading of blood within a centrifugal pump has been obtained and linked to its traumatic effect. It offers the possibility for an effective, multi-parameter optimisation of blood pumps in the design phase.
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Slevar, Amy E. "Mechanical fatigue in a magnetically levitated axial blood pump /." Online version of thesis, 2007. http://hdl.handle.net/1850/4893.
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Gomez, Arnold David. "Control of a magnetically levitated ventricular assist device /." Online version of thesis, 2009. http://hdl.handle.net/1850/10611.
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YU, Hai [Verfasser], and Dominique [Akademischer Betreuer] Thevenin. "Flow design optimization of blood pumps considering hemolysis / Hai Yu. Betreuer: Dominique Thévenin." Magdeburg : Universitätsbibliothek, 2015. http://d-nb.info/1072685698/34.
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YU, Hai Verfasser], and Dominique [Akademischer Betreuer] [Thévenin. "Flow design optimization of blood pumps considering hemolysis / Hai Yu. Betreuer: Dominique Thévenin." Magdeburg : Universitätsbibliothek, 2015. http://nbn-resolving.de/urn:nbn:de:gbv:ma9:1-6390.
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Karantonis, Dean Electrical Engineering & Telecommunications Faculty of Engineering UNSW. "Control of a rotary blood pump." Publisher:University of New South Wales. Electrical Engineering & Telecommunications, 2008. http://handle.unsw.edu.au/1959.4/43474.
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Implantable rotary blood pumps (RBPs) are an emerging technology designed to provide sufferers of heart failure with a viable treatment option which improves their medical prognosis and quality of life. The broad aim of this thesis is to address the need for a pump control strategy, and develop a solution whereby the implant recipient??s physiological requirements are continuously monitored in a non-invasive manner and met with an appropriate response by the RBP. Employing only the non-invasive signal of instantaneous pump impeller speed to assess flow dynamics, five physiologically significant pumping states have been identified in acute ex vivo porcine experiments (N=6). Two broader states, corresponding to normal and ventricular suction conditions, were readily discernable in clinical data from human implant recipients (N=10). Employing a classification and regression tree (CART) model, an automated real-time algorithm was developed to detect pumping states with a high degree of sensitivity and specificity. Both suction and normal states were detected without error in data from the animal experiments, and with a peak sensitivity/specificity, for detecting suction, of 99.11% / 98.76% in the human patient data. Algorithms to non-invasively estimate RBP flow and differential pressure in both steady- and pulsatile-flow environments were developed. Taking the pump feedback signals of speed and power, together with the blood haematocrit (or equivalent viscosity) level, as input parameters, several estimation models were developed via polynomial surface fitting and/or system identification methods, yielding clinically acceptable results (mean flow errors of 3.09% and 5.49%, and mean pressure errors of 1.80% and 6.47%, for the steady- and pulsatile-flow cases, respectively). An RBP control algorithm based on a non-invasive indicator of the implant recipient??s activity level has been proposed and evaluated in a software simulation environment. An Activity Level Index (ALI) forms the basis of an adaptive control module operating within a hierarchical multi-objective framework which imposes several constraints on the pump??s operating region. Three class IV heart failure cases of varying severity were simulated under rest and exercise conditions, and a comparison with other popular RBP control strategies was performed. Simulations of the proposed control algorithm exhibited the effective intervention of each constraint, resulting in an improved flow response and the maintenance of a safe operating condition, compared with other control modes.
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Swalen, Marcel Johannes Petrus. "Study of a bi-directional axial flow blood pump." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/6343.
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A common treatment for circulatory disorders is the application of rotary blood pumps to locally increase blood flow to required levels. Existing devices tend to support flow from inlet to outlet and in that direction only. This thesis presents a bi-directional pump that may enable ventricle assist devices (VAD) to support blood flow to the organs during systole, when rotating in one direction, and to increase coronary perfusion during diastole, when rotating in the other. For each flow direction blade profiles were designed and tested for performance. Both designs were merged to obtain a symmetric profile to provide flow support in both directions. This initial bi-directional design was optimised using computational fluid dynamics modelling. The model was set to accelerate to a maximum forward rotational speed of 8,000 rpm, change rotational direction after 300 ms and accelerate to 2,400 rpm whilst rotating backwards. Experimental testing was carried out to validate the computational results. In the forward direction, the pump was predicted to deliver 39 cm3 compared to 19 cm3 in the backward direction. Pressure heads reached maxima of 2.2 kPa in forward and 0.16 kPa in backward direction. Analysis of wall shear stress profiles at the blades’ surface showed that the maximum was 140 Pa lasting less than 300 ms in the forward direction, whilst in the backward direction this was approximately 23 Pa lasting for 700 ms. A design for the bi-directional blades is established and characterised computationally and experimentally. Analysis of the blade pressure profiles confirmed generation of pressure rise in both directions. The computational results for wall shear stress were predicted to be below the accepted limits of haemolysis. Recirculation zones were found at the outlet in the backward rotating direction. Future work may reduce those by using guide vanes at either side of the rotor.
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Rose, Michael Leon James. "Development of a muscle powered blood pump fluid mechanic considerations /." Thesis, Connect to electronic version, 1998. http://hdl.handle.net/1905/190.
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Thesis (Ph. D.)--University of Glasgow, 1998.Thesis submitted to the Department of Cardiac Surgery, Faculty of Medicine, University of Glasgow, in fulfilment of the degree of Doctor of Philosophy. Print version also available.
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Selby, Normajean. "STATE-VARIABLE FEEDBACK CONTROL OF A MAGNETICALLY SUSPENDED CENTRIFUGAL BLOOD PUMP." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1185567515.
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Moody, Kayla H. "Efficiency Evaluation of a Magnetically Driven Multiple Disk Centrifugal Blood Pump." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4384.
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Heart failure is expected to ail over 8 million people in America by 2030 leaving many in need of cardiac replacement. To accommodate this large volume of people, ventricular assist devices (VADs) are necessary to provide mechanical circulatory support. Current VADs exhibit issues such as thrombosis and hemolysis caused by large local pressure drops and turbulent flow within the pump. Multiple disk centrifugal pumps (MDCPs) use shearing and centrifugal forces to produce laminar flow patterns and eliminate large pressure drops within the pump which greatly reduce risks that are in current VADs. The MDCP has a shaft drive system (SDS) that causes leakage between the motor and housing that when implanted can cause blood loss, infection, thrombosis and hemolysis. To eliminate these adverse effects, a magnetic external motor-driven system (MEMDS) was implemented. An efficiency study was performed to examine the efficacy of the MEMDS by comparing the hydraulic work of the MDCP to the power required to run the pump. This was done by measuring inlet and outlet pressures, outlet flow rate and input current at various input voltages and resistances. The results showed the MDCP could produce physiologic flow characteristics with a flow rate of 4.90 L/min and outlet pressure of 61.33 mmHg at an impeller speed of 989.79 rpm. Other VADs generate flow rates around 5 L/min at rotational speeds of 2400 rpm for centrifugal pumps and 12000 rpm for axial pumps. When compared to the SDS, the MEMDS exhibited similar efficiencies of 3.89% and 3.50% respectively. This study shows promise in the advancement of MDCP.
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Ahrenstedt, Lage. "Surface modification of cellulose materials : from wood pulps to artificial blood vessels." Licentiate thesis, KTH, School of Biotechnology (BIO), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4437.
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This thesis describes the improvement of two radically different cellulose materials, paper and artificial blood vessels, constructed from two diverse cellulose sources, wood pulp and Acetobacter xylinum. The improvement of both materials was possible due to the natural affinity of the hemicellulose xyloglucan for cellulose.
Chemical and mechanical pulps were treated with xyloglucan in the wet-end prior to hand sheet formation or by spray application of dry hand sheets, loading a comparable amount of xyloglucan. The tensile strength increases for the wet-end treatment and spray application were 28% and 71% respectively for bleached soft wood, compared to untreated sheets (20.7 Nm/g). The corresponding strength increases for hand sheets made of thermo-mechanical pulp were 6% and 13% respectively compared to untreated sheets (42.4 Nm/g). The tendency for chemical pulp to be superior to mechanical pulp with respect to strength increase was valid even for tear strength and Scott-Bond. These results suggest, in agreement with other studies, that adhesion of xyloglucan to wood fibres is dependent on their degree of surface lignification.
Also, a method was developed to increase the blood compatibility of artificial blood vessels constructed of bacterial cellulose. Xyloglucan was covalently linked to the endothelial cell adhesion motif (Arg-Gly-Asp). To obtain this, new solid-phase coupling chemistry was developed. Xyloglucan oligosaccharides (XGO) were transformed into XGO-succinamic acid via the corresponding XGO--NH2 derivative prior to coupling with the N-terminus of the solid-phase synthesised Gly-Arg-Gly-Asp-Ser peptide. The resin-bound glyco-peptide was then cleaved and enzymatically re-incorporated into high molecular weight xyloglucan. The glyco-peptide was further adsorbed onto bacterial cellulose scaffolds, increasing the adhesion and proliferation of endothelial cells and therefore blood compatibility.
14
Jančík, Kryštof. "Návrh hydrodynamické ucpávky axiálního čerpadla s prstencovým motorem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378400.
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This diploma thesis deals with the design of a hydrodynamic seal of an axial pump with an annular motor, and it does so in three main thematic planes: research of current knowledge, simulation and experimental. The research section provides an overview of a broad problem of magnetic fluid seals (ferrohydrodynamic (FHD) seals), current developments in the field of simulation of internal flow in magnetic fluid and in the field of application of FHD technology in sealing liquids. It also covers a wider context of potential use for mechanical circulatory support systems that have had a significant impact on the proposed concept of a novel axial FHD seal. The remaining two thematic planes deal with his design and experimental testing.
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Khare, Aditi. "Estimation and control of the pump pressure rise and flow from intrinsic parameters for a magnetically-levitated axial blood pump /." Online version of thesis, 2008. http://hdl.handle.net/1850/7988.
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Foster, M. "The potential of a Tesla type device as a non pulsatile blood pump." Thesis, Middlesex University, 2006. http://eprints.mdx.ac.uk/13512/.
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A review of the published work on pumps designed to assist a failing biological heart has been made and discusses the different types of pump presently on the market with the characteristics of each. The materials used to make these pumps are also discussed, together with some of the methods of output control. The application to the patient is described together with the advantages and disadvantages. A Tesla type pump appeared to offer an alternative solution to those problems listed above. This is not a new design but appeared to offer advantages if applied to the application of pumping blood from outside the body. One of these was that at a constant speed, the pump supplied constant fluid pressure irrespective of the delivery. It also appears that the pump can give fluid shear stress levels that are less than the amount that will seriously damage blood components. A prototype pump has been built and tested. The pump achieved the performance target delivery of 10 I/min at a differential pressure of 200 mm Hg. This was considered to be greater than the average performance produced by existing blood pumps but the maximum performance that could be produced by the human heart under extreme conditions. The pump reached a maximum speed of about 4000 rev/min with a maximum power consumption of about 120 Watts. The results indicate that this type of pump is a potential blood pump in terms of the delivery and pressures achieved. The characteristic performance figures are within the envelope of published theoretical results. The pump tested here needs further development to improve the hydraulic performance. Recommendations are made for the direction of future work to improve the pump efficiency and flow patterns, biocompatibility and methods of production. Controls and power supply also need improvement.
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Seven, Ibrahim. "A CONCEPT FOR DIRECT CONTROL OF ROTARY BLOOD PUMP SPEED BY INLET PRESSURE." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1305597476.
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Kang, Jane. "Pump design for a portable renal replacement system." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39570.
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Most patients diagnosed with End Stage Renal Disease (ESRD) undergo hemodialysis. Traditional hemodialysis treatment requires patients spending three to five hours every other day while yielding the high waste level accumulated between treatments. These limitations in the current technology have spurred the development of a portable renal replacement system. The portable system will not only free the patients from visiting the clinic but also allow more frequent treatment that will lead to lower average waste level. To realize a portable system, the size and weight of hemodialysis system components should be reduced. This work analyzes the working principle of the pump and proposes a DC-motor and cam driven finger pump design. In addition, an analytical pump model is created for the optimization of the pump design. In vitro experiment conducted using the pump measured Creatinine levels over time, and the results validitate the design for the portable renal replacement system. The proposed pump design is smaller than 188 cm³ and consumes less than 4W while providing a flow rate of more than 100ml/min (the optimum flow rate for a portable system) for both blood and dialysate flows. The smallest pump of a portable renal replacement system in the literature uses check valves, which considerably increase the overall manufacturing cost and possibility of clogging. Compared to that pump, the proposed pump design achieved reduction in size by 40% and savings in energy consumption by 65% with the removal of valves. This simple and reliable design substantially enables development of a portable renal replacement system.
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Sciolino, Michael. "Development, Optimization, and Twisted Adjustment of an Axial Flow Blood Pump for Fontan Patients." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2946.
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Mechanical circulatory support options for patients with a failing Fontan physiology are significantly limited. This research advances the design of a cavopulmonary assist device as a bridge-to-transplant or bridge-to-recovery for Fontans. A fixed-bladed impeller and diffuser for this pump was designed and optimized using ANSYS CFX™ 12.1 software. Building upon the fixed bladed geometry, a novel flexible impeller prototype was created and evaluated by hydraulic testing. In contrast to the fixed design, the flexible impeller enabled a range of blade angles from 60°-150°. Improvement in pump performance was achieved. Pressure generation was found to decrease as a function of higher flow rates and increase as a function of faster rotational speeds and larger blade angles. The designs were able to produce 1-25 mmHg for 0.5-4 L/min at 5000-8000 RPM, which is sufficient to assist Fontan patients. The findings support the continued development of this blood pump with pitch-adjusting characteristics.
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Hilton, Andrew. "Proposal for a cost-effective centrifugal rotary blood pump : design of a hybrid magnetic/hydrodynamic bearing." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/13919/.
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The growing worldwide prevalence of cardiovascular diseases (CVD) such as chronic heart failure (CHF) highlights the need for an effective treatment method. Annually, there are an estimated 17.5 million deaths caused by cardiovascular diseases worldwide, representing 30% of all global deaths; of these deaths approximately 50% are due to CHF [1] and about 80% occur in low- and middle-income countries [2]. If current trends are allowed to continue, by 2015 an estimated 20 million people annually will die from CVD [3]. Each year, only about 3,000 people receive a heart transplant as the only current definitive long-term treatment for end-stage CHF. To compound the severity of the situation, organ donations are decreasing (4). Implantable blood pumps offer an effective treatment to CHF, either as a bridge to transplantation / recovery, or as destination therapy i.e. use of long term mechanical circulatory support in patients with end-stage heart failure without the intention of eventual heart transplantation. With the number of sufferers of CHF rising in both the developed and developing world it becomes pertinent to design a cost effective device. It is the objective of this work to investigate the proposal of a new cost-effective Centrifugal Rotary Blood Pump (CRBP), which employs previously unutilized design methodology. Through the replacement of those complex, custom components seen within existing CRBPs with standard off-the-shelf components, and the implementation of high-throughput manufacturing processes, such as injection moulding, a reduction in component parts allows for a reduced profit margin and hence a reduced total cost of device. It is proposed by the author that the current production cost of LVAD devices may be reduced by up to 95%. The work presented in this thesis identifies the principal difference between current pump designs; this is their bearing system. It is proposed here to form a new classification of bearing type that combines a passive magnetic bearing and a hydrodynamic bearing such that the relative potential merits of both systems may be exploited. Through the amalgamation of established design techniques with other more modern design practices a rigorous, adaptive design tool has been produced that CRBP designers may use to quickly obtain full impeller and volute geometry from few input parameters. The geometry output provides a platform from which a new conceptual Left Ventricular Assist Device (LVAD) has been envisaged. Through experimental and computational analysis of the magnetic coupling, this investigation has shown that it is possible to integrate the magnetic bearing and the drive system into one component of design; it is possible to design a magnetic coupling that not only acts as the drive system for a CRBP, but as a bearing system that offers both axial and radial bearing forces. A spiral groove bearing (5GB) has been implemented as the hydrodynamic bearing as part of the hybrid system. Experimental investigation has shown the spiral groove bearing to be anti traumatic, which may be attributed to the short residence time of blood in the bearing. However, a reduction in the anticipated load capacity shows that the bearings are operating on a reduced viscosity; this is an indication of cell exclusion within the 5GB. Comparisons to aqueous glycerol tests of known viscosities have shown that the blood bearing is operating on a viscosity close to that of plasma. It is suggested that a "shear front differential" is the mechanism behind cell exclusion, in which RBCs migrate away from areas of high shear stress into areas of relatively low shear stress. This investigation has demonstrated the suitability of the hybrid magnetic / hydrodynamic bearing for use in a new CRBP. It has been shown that the electromagnetic drive system intended for implementation in to this CRBP can be used as an effective passive magnetic bearing. It is intended that the axial and radial bearing forces produced by the drive system are balanced by a conical spiral groove thrust bearing. The incorporation of the hydrodynamic bearing into the magnetic bearing transforms the previously unstable passive magnetic bearing to a stable hybrid bearing. The stability of the system has been predicted through numerical analysis of the stiffness matrix and through satisfaction of the stability criteria. The natural frequencies of the system have been calculated; these are shown to be sufficiently different from any excitation frequencies identified that may cause the system to behave in an unstable fashion at the operational speed of the pump. The main point to be realized from the analysis of the hybrid bearing system, however, is that the proposed set-up of the hybrid bearing is not feasible due to the effect of cell exclusion, which causes the SGB to operate on a reduced viscosity. The reduction in viscosity reduces the load capacity of the SGB; the magnetic preload on the impeller cannot be balanced by the chosen SGB geometry. Recommendations have been made as to the design parameters that may be altered such that the design intent of the proposed system may be realised. Future work must concentrate on the realization of that design intent through the manufacture of a prototype, which can provide a proof-of-concept for the proposed system. The work presented here provides a feasibility study for the novel hybrid bearing / drive system and provides sound foundation upon which a prototype may be based.
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Fu, Minghua. "Development and evaluation of a robust and intelligent digital control system for a rotary blood pump /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487953204280546.
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Patel, Karnal. "Design and development of a pulsatile axial flow blood pump as a left ventricular assist device." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/11085.
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Each year all over the world, Millions of patients from infants to adults are diagnosed with heart failure. A limited number of donor hearts available for these patients results in a tremendous demand of mechanical circulatory support (MCS) system, either in the form of total artificial heart (TAH) or a ventricular assist device (VAD). Physiologically MCS are expected to provide heart; a time to rest and potential recovery by unloading the ventricle, while maintaining the adequate peripheral as well as coronary circulation. Existing ventricular assist devices (VAD) have employed either displacement type pulsatile flow pumping systems or continuous flow type centrifugal/rotodynamic pumps systems. Displacement type devices produce a pulsatile outflow, which has significant benefits on vital organ function and end organ recovery. Continuous flow devices are small and can be placed within body using minimal invasive procedures, in addition they reduces infection as well as mechanical failure related complications. Despite availability of success stories for both types of pumping systems, the selection of the either of them is an ongoing debate. This thesis aims to merge the advantages of displacement pumps (pulsatile flow) and axial-flow pumps (continuous flow) into a novel left vertical assist device (LVAD), by designing a novel minimal invasive, miniature axial-flow pump producing pulsating outflow for the patients having early heart failure and myocardial infarction as a Bridge-To-Recovery (BTR) or Bridge-To-Decision (BTD) device. The design of VAD, the experimental setup and dedicated control system were developed for the in vitro evaluation of pulsatile flow. Computational fluid dynamics (CFD) had been employed for the detail investigation of pulsatile flow. In addition, CFD was also applied to optimize the pulse generation for low haemolysis levels. Outcome of the study produces comprehensive understanding for the generation of pulsatile flow using an axial flow pump. Further, it provides the means of generating a controlled pulse that can regulate flow rate for varying heart rate within low haemolysis levels.
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Song, Chen [Verfasser], and Vincent [Akademischer Betreuer] Heuveline. "Uncertainty Quantification for a Blood Pump Device with Generalized Polynomial Chaos Expansion / Chen Song ; Betreuer: Vincent Heuveline." Heidelberg : Universitätsbibliothek Heidelberg, 2018. http://d-nb.info/1177252406/34.
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Thamsen, Bente Kristina [Verfasser], Klaus [Akademischer Betreuer] Affeld, Christian Oliver [Gutachter] Paschereit, Klaus [Gutachter] Affeld, and Tim Arne Simon [Gutachter] Kaufmann. "A two-stage rotary blood pump design to reduce blood trauma / Bente Kristina Thamsen ; Gutachter: Christian Oliver Paschereit, Klaus Affeld, Tim Arne Simon Kaufmann ; Betreuer: Klaus Affeld." Berlin : Technische Universität Berlin, 2016. http://d-nb.info/1156182131/34.
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Jagani, Jakin Nitinkumar. "Design of Percutaneous Dual Propeller Pump to assist Patients with Single Functional Ventricle." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/82667.
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Various congenital heart defects (CHDs) are characterized by the existence of a single functional ventricle, which perfuses both the systemic and pulmonary circulation in parallel. A three-stage palliation procedure, including the final Fontan Completion, is often adopted by surgeons to treat patients with such CHDs. However, the most common outcome of this surgery, an extra-cardiac total cavopulmonary connection (TCPC), formed by suturing the inferior vena cava (IVC) and superior vena cava (SVC) to the pulmonary arteries (PAs), results in non-physiological flow conditions, systemic venous hypertension, reduced cardiac output, and pressure losses, which ultimately calls for a heart transplantation. A modest pressure rise of 5-6 mm Hg would correct the abnormal flow dynamics in these patients. To achieve this, a novel conceptual design of a percutaneous dual propeller pump inserted and mounted inside the TCPC is developed and studied.
The designed blood pump is percutaneously inserted via the Femoral vein and deployed at the center of Total Cavopulmonary Connection (TCPC). The two propellers, each placed in the Superior Vena Cava (SVC) and the Inferior Vena Cava (IVC) are connected by a single shaft and motor, and thus rotate at same speed. The device is supported with the help of a self-expanding stent which would be anchored to the walls of the IVC and the SVC. An inverse design methodology implementing Blade Element Momentum theory and Goldstein's radial momentum loss theory was employed to generate the blade profiles for the studied propeller pumps. The propeller blade profiles generated from the inverse design optimization code were examined for hydraulic performance, blood flow pattern and potential for hemolysis inside the TCPC using 3-D computational fluid dynamics (CFD) analysis. The Lagrangian particle tracking approach in conjunction with a non-linear mathematical power law model was used for predicting the blood damage potential of the analysed blood pump designs by calculating the scalar shear stress history sustained by the red blood cells (RBC).
The study demonstrated that the IVC and SVC propeller pumps could provide a pressure rise of 1-20 mm Hg at flow rates ranging from 0.5 to 5 lpm while rotating at speeds of 6,000-12,000 rpm. Moreover, the average Blood Damage Index (BDI), quantifying the level of blood trauma sustained by the RBCs for the analyzed propeller pump designs, was found to be around 3e-04% to 4e-04% which is within the acceptable limits for an axial flow heart assist device. Thus, such a dual propeller blood pump configuration could potentially provide assistance to Fontan patients by unloading the single functional ventricle thereby acting as a bridge to transplantation and recovery until a donor heart is available.Master of Science
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Čejka, Pavel. "Studie membránového čerpadla s lineárním motorem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229733.
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The diploma thesis is aimed at the constructional design of diaphragm pumps with a linear motor. This pump is supposed to be used in medicine for pumping the blood or as an artificial heart. The basic facts, which are focused on the function of the heart and artificial heart, are mentioned in the first parts of the thesis. The next parts describe the diaphragm pumps and the constructional ways of their diaphragm fixation. Furthermore, the basic calculations, describing the function of the pump, are derived there. The basic parameters of the pump are also calculated. The thesis also contains the description of the body pump construction, whose working room is optimized by CFD calculation before the pump is manufactured. The final part of the thesis is concentrated on the measurement evaluation of produced pump model.
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Kinnunen, E. M. (Eeva-Maija). "Perioperative bleeding and use of blood products in coronary artery bypass grafting." Doctoral thesis, Oulun yliopisto, 2015. http://urn.fi/urn:isbn:9789526210025.
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Abstract Coronary artery disease (CAD) is the leading cause of death in developed countries. In patients with complex CAD, coronary artery bypass grafting (CABG) remains the preferred treatment as it can provide long-lasting results. However, CABG carries a significant risk of excessive perioperative bleeding and other complications, which may deteriorate the prognosis. Transfusion of blood products is generally used to compensate blood loss. However, both bleeding and blood transfusions have been shown to be associated with an adverse outcome. This cohort study aimed to clarify the impact of perioperative bleeding and the use of different blood products in the development of perioperative complications in 2,764 patients undergoing isolated CABG. The universal definition of perioperative bleeding classification (UDPB) was employed to stratify the severity of bleeding. Additionally, the impact of storage time of transfused red blood cells (RBCs) on the outcome was investigated. Increased UDPB classes, particularly classes 3 and 4, were associated with significantly poorer immediate and late outcome. RBC transfusion in patients who underwent elective off-pump CABG was independently associated with increased troponin I release indicating myocardial injury. Prolonged storage duration of transfused RBCs did not affect immediate and late outcome of patients with moderate bleeding. The most remarkable risk factors for stroke after off-pump CABG were any degree of atherosclerosis of the ascending aorta as well as transfusion of platelets and/or solvent/detergent-treated plasma. The UDPB classification appears to be a promising research tool to stratify the severity of perioperative bleeding and to assess its prognostic impact after coronary surgery. Prevention of major bleeding that leads to blood transfusion may protect from myocardial injury and stroke and possibly result in better early and late outcomes. Patients with a diseased ascending aorta could be considered at high risk of stroke because of their risk of generalized atherosclerosis. In case of mildly diseased aorta, the “no-touch” aorta policy should be considered with the intention of preventing postoperative strokeTiivistelmä Sepelvaltimotauti on yleisin kuolinsyy kehittyneissä maissa. Potilailla, joilla on vaikea monen suonen tai vasemman sepelvaltimon päärungon tauti, sepelvaltimoiden ohitusleikkaus on edelleen paras hoitovaihtoehto, koska sillä pystytään saavuttamaan pitkäkestoisia tuloksia. Kuitenkin ohitusleikkaukseen liittyy suuri riski leikkauksen aikaiselle tai jälkeiselle verenvuodolle ja muille haittatapahtumille, jotka osaltaan huonontavat potilaan ennustetta. Vuodon hoitona käytetään yleisesti verensiirtoa. Kuitenkin on osoitettu, että sekä verenvuoto että verituotteiden anto lisäävät riskiä komplikaatioille. Tämän kohorttitutkimuksen tavoitteena oli selvittää tarkemmin leikkauksen yhteydessä ilmenevän vuodon ja siihen liittyvän verensiirron vaikutuksia leikkauksen jälkeisten haittatapahtumien kehittymiseen 2764 ohitusleikatulla potilaalla. Universal Definition of Perioperative Bleeding (UDPB) -luokitusta käytettiin vuodon vaikeusasteen luokittelemiseen. Lisäksi tutkittiin siirrettyjen punasolujen varastointiajan vaikutusta potilaan ennusteeseen. Korkeammat UDPB-luokat, erityisesti luokat 3 ja 4, liittyivät merkittävästi huonompaan lyhyen ja pitkän aikavälin ennusteeseen. Potilailla, joille oli tehty kiireetön ohitusleikkaus ilman sydän-keuhkokoneen käyttöä, punasolujen anto oli itsenäinen riskitekijä suurentuneelle troponiini I -päästölle eli sydänlihasvauriolle. Pidentynyt punasolujen varastointiaika ei ollut yhteydessä lyhyen tai pitkän aikavälin ennusteeseen potilailla, jotka olivat vuotaneet kohtalaisesti. Merkittävimmät riskitekijät ilman sydän-keuhkokonetta tehdyn leikkauksen jälkeiselle aivoinfarktille olivat minkä tahansa asteinen nousevan aortan ateroskleroosi sekä verihiutaleiden ja/tai jääplasman anto. UDPB-luokitus vaikuttaa lupaavalta tutkimustyökalulta verenvuodon vaikeusasteen luokitteluun. Lisäksi sitä voidaan käyttää vuodon ennusteellisen vaikutuksen arvioimiseen ohitusleikkauksen jälkeen. Runsaan verenvuodon ja siihen liittyvän verensiirron ehkäiseminen saattaa suojata potilasta sydänlihasvauriolta ja aivoinfarktilta ja mahdollisesti johtaa parempaan lyhyen ja pitkän aikavälin ennusteeseen. Potilaita, joilla on nousevan aortan ateroskleroosi, voisi pitää suuressa aivoinfarktiriskissä yleisen ateroskleroosiriskin vuoksi. Potilailla, joilla on lieväkin nousevan aortan ateroskleroosi, tulisi harkita aortan jättämistä pihdittämättä aivoinfarktin ehkäisemiseksi
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Gillespie, Erin. "Feasability assessment of a Kalman filter approach to fault detection and fault-tolerance in a highly unstable system : the RIT heart pump /." Online version of thesis, 2009. http://hdl.handle.net/1850/9834.
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Thatte, Suhas Madhusudan. "In Vitro Flow Visualization Study of the Interface between Outflow Graft of Ventricular Assist Device and Aorta." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd_retro/107.
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Heart transplant is often considered the best treatment for prolonged left ventricular failure. However due to limited donor hearts and ineligibility of some patients to get a transplant, heart assist devices are considered a short/long term option to assist the failing ventricle. Numerous in vitro and animal trials are conducted to study the flow fields in artificial ventricles to avoid hemolysis and thrombosis but the effects of flow fields corresponding to the angle of LVAD insertion into the aorta are often neglected. This experiment uses 30, 60 and 90 degree glass models to signify different angles of the surgical end to side anastomosis. Particle Image Velocimetry is used to study the flow fields at the interface and determine optimum angle amongst the three to avoid blood trauma. Use of a 30 degree glass interface minimizes stagnation zone, recirculation patterns, flow reversal, high shear region and other flow irregularities which may lead to reduced hemolysis, thrombosis and blood trauma in a clinical setting.
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Chopski, Steven. "Experimental and Computational Assessment of Mechanical Circulatory Assistance of a Patient-Specific Fontan Vessel Configuration." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3223.
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The treatment of single ventricle anomalies is a formidable challenge for clinical teams caring for patients with congenital heart disease. Those patients fortunate to survive surgical palliation contend with lifelong physical limitations and late stage pathophysiology. A mechanical blood pump specifically designed to increase pressure in the great veins would augment flow through the lungs and provide hemodynamic stability until a donor heart is located. To support the development of such medical devices, this research characterized the fluid dynamics of mechanical assistance in the Fontan circulation by performing numerical analyses and particle image velocimetry (PIV) studies in a patient-specific in vitro model. This project investigated the performance of three pump prototype configurations. ANSYS-CFX was used to conduct the computational studies for a range of operating conditions and degrees of Fontan dysfunction. Pressure generation, blood trauma predictions, shear stresses, fluid streamlines, and velocity profiles were examined. Three-dimensional PIV studies were completed and compared to the numerical estimations. Computational findings and experimental data correlated to within literature expectations. Blood damage levels, shear stresses, and fluid residence times remained reasonable or below threshold limits. The blood pump configurations met expectations by achieving target design specifications for clinical application. The pumps enhanced the rate of hydraulic power gain in the cavopulmonary circuit, reduced inferior vena cava pressure, and minimally increased pulmonary arterial pressure. The blood pump with the twisted protective stent produced the most rapid increase in the rate of power gain and the highest pressure generation. The PIV measurements illustrated a strong dependency of the fluid dynamics on the patient-specific vessel geometry and the particular pump design. The pump having the twisted cage outperformed the other designs and had a dominating impact on the blood flow distribution in the cavopulmonary circuit. A strong rotational component in the flow was observed leaving the pumps. These results confirm that mechanical cavopulmonary assistance is a viable therapeutic option. Significant knowledge into a new class of blood pumps and how these pumps interact with a single ventricle physiology was gained, thus advancing the state-of-the-art in mechanical circulatory support and addressing a significant human health problem.
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Silva, Cibele da. "Ensaios in vivo e avaliação clínica de bomba de sangue para circulação extracorpórea durante cirurgia cardíaca : spiral pump." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263520.
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Orientadores: Cecília Amélia de Carvalho Zavaglia, Aron José Pazin de AndradeDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
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Resumo: Neste trabalho foram elaborados os métodos e realizados estudos In Vivo e Avaliação Clínica de uma Bomba de Sangue para Circulação Extracorpórea (CEC), durante Cirurgia Cardíaca, denominada Spiral Pump® (SP). Esses estudos foram realizados com o objetivo de avaliar o desempenho e segurança da bomba, finalizando assim o projeto e avaliando a SP como um produto em sua aplicação rotineira durante as cirurgias cardíacas. A SP utiliza, simultaneamente, dois princípios de bombeamento, o centrífugo e o axial, proporcionados por sua geometria cônica, visando aumentar a eficiência de bombeamento sem o aumento dos índices de destruição dos elementos figurados do sangue. O primeiro passo para avaliação In Vivo foi à elaboração de um protocolo para avaliação In Vivo animal e sua submissão a Comissão de Ética para Uso de Animais (CEUA) do Instituto Dante Pazzanese de Cardiologia (IDPC). As avaliações In Vivo consistiram em instalação normal da CEC, em animais suínos, utilizando a SP conectada a um módulo de acionamento e, para fins de comparação, foi realizado o mesmo procedimento com a Bio-Pump®. Foram realizados seis experimentos com a SP, sendo o primeiro considerado piloto, e três experimentos com a Bio-Pump®, com duração de seis horas cada. As observações realizadas pela equipe médica e pela perfusionista demonstraram grande semelhança de funcionamento entre as duas bombas, inclusive em relação a vibrações, ruídos e facilidade de utilização. As bombas foram comparadas em relação à medição do trauma, analisado a partir da evolução da hemoglobina livre no plasma (PFH). Analisando os resultados laboratoriais e de hemólise obtidos com a SP e a Bio-Pump®, pode-se verificar que não existem diferenças significativas entre elas. Com resultados satisfatórios nos ensaios In Vivo, a SP foi aprovada para Avaliação Clínica, realizada de acordo com a legislação vigente. Foi elaborado um Protocolo de Pesquisa Clínica que seguiu a Resolução ANVISA número 39 de 05 de junho de 2008, que estabelece requisitos para realização de pesquisa clínica no Brasil. Esse protocolo foi submetido ao Comitê de Ética em Pesquisa (CEP) do IDPC e ao Conselho Nacional de Ética em Pesquisa (CONEP). A pesquisa clínica foi realizada no Centro Cirúrgico do IDPC em um grupo de quarenta pacientes com indicação de cirurgia cardíaca com CEC, com ou sem cardioplegia, ambos os sexos, adultos, peso corporal mínimo de 50 kg. Durante a CEC, a SP substituiu as convencionais bombas de roletes no circuito de CEC. Todos os pacientes foram entrevistados e autorizaram a realização do estudo, assinando do Termo de Consentimento Livre e Esclarecido. Foram coletados dados comumente monitorados durante uma cirurgia cardíaca e foram realizados, nos períodos de pré e pós CEC, exames de Desidrogenase Láctica (U/L), Plaquetas (mil/mm3), Fibrinogênio (mg/dL), além de monitoração da hemólise através de fita de urianálise. Os procedimentos transcorreram de forma habitual, e os parâmetros mantiveram-se dentro do esperado para o estudo, demonstrando a eficiência e segurança da SP como bomba para circulação extracorpórea durante cirurgia cardíaca
Abstract: Were developed methods and studies In Vivo and clinical evaluation were conducted with a blood pump for cardiopulmonary bypass (CPB), during cardiac surgery, the Spiral Pump® (SP). These studies are designed to assess the performance and safety of SP, finalizing the project and evaluating the SP as a product in its routine application during heart surgeries. The SP uses simultaneously, two principles of pumping, axial and centrifugal, provided by its conical geometry, in order to increase pumping efficiency without increased levels of destruction of the figured elements from blood. First step for In Vivo evaluation was the development of a protocol for In Vivo experiments and its submission to the "Ethic Committee for Animal Use" of Institute Dante Pazzanese of Cardiology (IDPC). The In Vivo assessments consisted of normal installation of the CPB in pigs, using the SP connected to a driver console and, for comparison purposes, the same procedure was performed with Bio-Pump®. Six experiments were performed with SP and three experiments with Bio-Pump®, lasting six hours each. Observations made by medical team showed great similarity between two pumps, including characteristics of vibration and noise. Two pumps were compared concerning to measurement of trauma, through the evolution of plasma free hemoglobin (PFH) and the PFH variation (?PFH). Analyzing laboratory results and hemolysis, from In Vivo assays with SP and the Bio-Pump®, we can observe no significant differences between them. With satisfactory results from In Vivo assays, SP was approved for clinical evaluation, carried out in accordance with current legislation. A Clinical Research Protocol was elaborated following ANVISA (National Health Surveillance Agency) resolution number 39 of 2008, which establishes requirements for conducting clinical research in Brazil. This Protocol was submitted to the Ethic Committee Research of IDPC for review and subsequently to National Council of Ethics in Research. Clinical research was conducted at operating room of IDPC in a group of forty patients under cardiac surgery with CPB, both sexes, adults, minimum of 50 kg of body weight. During CPB, SP replaced conventional CPB roller pump. All patients were interviewed and had authorized this study, signing of consent form. Usually monitored data were collected during a heart surgery and additional examinations were carried out at periods of pre and post CEC such as: Lactic dehydrogenase exams (U/L), platelets (1000/mm3), Fibrinogen (mg/dL), as well as monitoring of hemolysis by urianalysis tape. All procedures were as usual way, and all parameters remained as expected for this study, demonstrating the performance and safety of SP as pump for CPB during heart surgery
Mestrado
Materiais e Processos de Fabricação
Mestra em Engenharia Mecânica
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Pfluecke, C., M. Christoph, S. Kolschmann, D. Tarnowski, M. Forkmann, S. Jellinghaus, D. M. Poitz, et al. "Intra-aortic balloon pump (IABP) counterpulsation improves cerebral perfusion in patients with decreased left ventricular function." Sage, 2014. https://tud.qucosa.de/id/qucosa%3A35364.
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Background: The current goal of treatment after acute ischemic stroke is the increase of cerebral blood flow (CBF) in ischemic brain tissue. Intra-aortic balloon pump (IABP) counterpulsation in the setting of cardiogenic shock is able to reduce left ventricular afterload and increase coronary blood flow. The effects of an IABP on CBF have not been sufficiently examined. We hypothesize that the use of an IABP especially enhances cerebral blood flow in patients with pre-existing heart failure.
Methods: In this pilot study, 36 subjects were examined to investigate the effect of an IABP on middle cerebral artery (MCA) transcranial Doppler (TCD) flow velocity change and relative CBF augmentation by determining velocity time integral changes (ΔVTI) in a constant caliber of the MCA compared to a baseline measurement without an IABP. Subjects were divided into two groups according to their left ventricular ejection fraction (LVEF): Group 1 LVEF >30% and Group 2 LVEF ≤30%.
Results: Both groups showed an increase in CBF using an IABP. Patients with a LVEF ≤30% showed a significantly higher increase of ΔVTI in the MCA under IABP augmentation compared to patients with a LVEF >30% (20.9% ± 3.9% Group 2 vs.10.5% ± 2.2% Group 1, p<0,05). The mean arterial pressure (MAP) increased only marginally in both groups under IABP augmentation.
Conclusions: IABP improves cerebral blood flow, particularly in patients with pre-existing heart failure and highly impaired LVEF. Hence, an IABP might be a treatment option to improve cerebral perfusion in selected patients with cerebral misperfusion and simultaneously existing severe heart failure.
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Leme, Juliana. "Desenvolvimento e estudo in vitro de um dispositivo de suporte circulatório temporário." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/98/98131/tde-26042016-090152/.
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Um modelo de bomba centrífuga de sangue, denominado Dispositivo de Suporte Circulatório Temporário (DSCT), foi desenvolvido para utilização como ponte para decisão e/ou ponte para recuperação. Durante o seu desenvolvimento, foi utilizada a proporção áurea para cálculos das medidas dos componentes. Baseando-se nas condições de uso, foi desenvolvido um modelo de DSCT com cone externo, base externa, sistema de mancal e rotor. Com o uso da espiral áurea, foi possível desenvolver três diferentes modelos de aletas para o rotor, denominadas como aleta reta (rotor 1), aleta curvada (rotor 2) e aleta mais curvada (rotor 3). Foram realizados testes In Vitro de desempenho hidrodinâmico e de hemólise. Para avaliar o desempenho hidrodinâmico, foi utilizado um circuito de teste fechado e os dados de pressão, fluxo e rotação foram registrados. Curvas foram geradas mostrando pressão e fluxo (?P x F) para diferentes rotações, comparando os três protótipos. Os três modelos de rotores apresentaram desempenho hidrodinâmicos semelhantes em baixas rotações e os rotores 1 e 3 apresentaram um melhor desempenho para todas as outras rotações. Para avaliar a hemólise foi utilizado um circuito fechado padronizado pelas normas ASTM F1830 e F1841, com sangue bovino, fluxo de 5 L/min e pressão de 100 mmHg e, posteriormente, calculados os valores do Índice Normalizado de Hemólise (INH). Os resultados obtidos de INH mostraram que o DSCT com rotor 3, aletas com curvas mais acentuadas, obteve o menor valor de hemólise, INH = 0,00332 ± 0,00136 g/100L, considerado excelente para esta aplicação, contra os valores de INH = 0,03951 ± 0,03031 g/100L para o rotor 1 e INH = 0,05115 ± 0,03147 g/100L para o rotor 2. Considerando os resultados de hemólise obtidos, pode-se concluir que o modelo de dispositivo de suporte circulatório utilizando o rotor tipo 3, com aletas mais curvadas, apresentou resultado mais favorável e sendo o mais indicado. As próximas etapas do desenvolvimento estão sendo preparadas, como visualização do comportamento do fluxo e ensaios In Vivo.A new model of centrifugal blood pump, a temporary circulatory support device (TCSD), has been developed and tested to be used as bridge to decision or bridge to recovery. During TCSD development, golden ration was utilized to calculate mechanical component dimensions. Based on conditions of use, a TCSD has been developed with external housing, bearing system and impeller. Three impellers with different blade curvatures were created: straight blades (rotor 1), low curvature blades (rotor 2) and high curvature blades (rotor 3). Two comparative In Vitro tests were conducted: hydrodynamic performance and hemolysis test. A mock loop system was used for hydrodynamic performance test and pressure, flow and rotational speed were recorded. Curves showing total pressure head versus flow (?PxF) were obtained at different rotational speeds, comparing all three rotors. Results showed similar hydrodynamic performance for low speeds. However, rotor 1 and rotor 3 showed better hydrodynamic performance for high speeds. Standardized closed circuitry (ASTM F1830 and F1841) was used to evaluate hemolysis, filled with bovine blood. Flow was 5 l/min against total pressure head of 100 mmHg. Normalized Index Hemolysis (NIH) was calculated. Hemolysis tests showed better NIH for rotor 3, NIH = 0.00332±0.00136 g/100L (lower than excellent result found in literature) against values of NIH = 0.03951±0.03031 g/100L for rotor 1 and NIH = 0.05115±0.03147 g/100L for rotor 2. With those results, we conclude that, for this model TCSD, the rotor 3 with high curvature blades is indicated. Thereby, future stages of development such as flow visualization and In Vivo trials are being prepared.
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Adawi, Rahim. "Preventing fatal effects of overworking : Product design solution." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-15473.
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“Overworking to death” is a phenomenon that has been noticeable in developing countries. The cause of death is mainly through ischemic strokes. While the victims’ occupations differed, they all shared a common characteristic, being positioned in a sedentary work, ranging from IT workers to doctors. This project’s aim was to develop a product that prevented or decreased the strokes that derived from sedentary overwork. This was mainly tackled by preventing one of the three causes of developing blood props, slowed blood flow. In order to gather rich data of the phenomenon, a qualitative study was conducted in China, during two months. By doing an extensive structured sampling, information rich data could be gathered during a short period of time. Data were derived from observations, questionnaires and an interview, which then was interpreted to customer needs and the final product specification. The final product became a trouser with an in built dynamic compression mechanic, that can compress the veins mostly during sitting activities, in order to prevent blood stasis. The compression mechanic works like the Chinese finger trap; compressing the calves while sitting and stretching the legs forward. It is made only out of polysaccharides fibres; cotton and corn."Guolaosi" eller död från överarbete är ett fenomen som i regel uppkommer bland utvecklingsländer. Dödsorsaken är huvudsakligen genom stroke. Offrens yrken varierar allt från professorer, IT-arbetare till läkare. De delar dock en sak gemensamt; att arbeta under långa perioder stillasittande. Projektets mål var att utveckla en produkt som minskar dödliga följderna av sedentära överarbete, genom att förebygga en av de tre orsakerna för att utveckla blodproppar; saktad blodström. Målgruppen var då kineser av de yrken som hade tidigare drabbats av fenomenet. För att samla informationsrika data om fenomenet genomfördes en kvalitativ studie i Kina under två månader. Genom att göra en omfattande strukturerad provtagning kunde informationsrika data samlas under en kort tidsperiod. Fältstudien bestod av observationer, frågeformulär och en intervju, som då tolkades till kundbehov och eventuellt produktspecifikationen. Den slutliga produkten kom att bli ett par byxor med en inbyggd dynamisk komprimeringsmekanism, som kan komprimera venerna under sittande aktiviteter, för att förhindra saktad blodström. Kompressionsmekanismen fungerar som den kinesiska fingerfällan. Den komprimerar blodkärlen medan personen sitter och sträcker benen framåt. Produkten är konstruerad på så sätt att den kan tillverkas endast av polysackariders tråd, från bomull och majs. Vilket är lämpligt för Kinas lokala resurser.
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Quintas, Ana Rita Pires. "Dynamic modelling and analysis of hydraulic forces in radial blood pumps." Master's thesis, 2015. http://hdl.handle.net/1822/39616.
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Dissertação de mestrado integrado em Biomedical Engineering Biomaterials, Biomechanics and RehabilitationCardiovascular diseases are the most frequent cause of death worldwide and one of the most important challenges that health systems across the world have to face. Despite all their merits, conventional medication therapy and heart transplants present, respectively, important limitations of effectiveness and availability. As a result, cardiac mechanical assist devices have become a crucial and widely accepted option. The last decades witnessed the proliferation of a wide range of such devices, including the ReinVAD LVAD, which is a third generation blood pump currently under development by the Helmholtz-Institute for Biomedical Engineering and ReinVAD GmbH. The present work focused on the dynamic analysis of the hydraulic forces acting on impellers of radial blood pumps. This approach was tailored to the ReinVAD LVAD, aiming to support its development. An analytical model of the axial hydraulic forces acting on this pump was developed and implemented in MATLAB® and SIMULINK®, allowing for the estimation of these forces under different scenarios and pump designs. As for the radial hydraulic force, a quick estimation methodology was adopted, which validated the initial assumption that the magnitude of this force would not be very relevant when compared to the one of the axial hydraulic force. Applying this axial hydraulic force model, the two major variables of the pump operation - flow rate and rotation speed - were tested. The resultant axial hydraulic force magnitude was estimated, and its behaviour with changing conditions was discussed. Under a normal operating context, the magnitude of this force was estimated to be in the order of 0 to 1 N. Moreover, it was concluded that this force decreased in magnitude with increasing flows, while it increased in magnitude with increasing rotation speeds. To understand these results, the individual effects that affected the different components of the axial hydraulic resultant force were analysed in detail. The conclusions of this study were found to match the existing literature on similar pumps. An additional validation of the model was performed, comparing its results with available CFD simulations of the ReinVAD LVAD. The predictions of the model and of the CFD simulations regarding the tendencies of the forces were found to be consistent in both simulations.
As doenças cardiovasculares constituem a principal causa de morte no mundo, apresentando-se como um dos mais críticos desafios enfrentados pelos sistemas de saúde. Apesar de todos os seus méritos, a medicação convencional e os transplantes cardíacos apresentam importantes limitações, respetivamente de eficácia e disponibilidade. Estas razões levaram a que as bombas cardíacas se tenham tornado uma opção clínica amplamente aceite e crucialmente importante. Assim, as últimas décadas testemunharam a proliferação de um leque diversificado destes dispositivos, incluindo o ReinVAD LVAD, um dispositivo de terceira geração em desenvolvimento pelo Helmholtz-Institute for Biomedical Engineering e pela ReinVAD GmbH. A presente investigação focou-se numa análise dinâmica das forças hidráulicas que atuam em bombas cardíacas radiais. Esta abordagem foi adaptada ao caso específico do ReinVAD LVAD, de forma a apoiar o seu desenvolvimento. Um modelo analítico das forças axiais hidráulicas que atuam nesta bomba foi assim desenvolvido e implementado em MATLAB® e SIMULINK®, permitindo estimar estas forças em diferentes cenários. Já a força radial hidráulica foi estimada de acordo com uma abordagem simplificada, validando a hipótese de que a sua magnitude é pouco relevante quando comparada com a da força axial hidráulica. Aplicando o modelo desenvolvido para as forças axiais hidráulicas, foram testadas as duas principais variáveis do funcionamento da bomba – fluxo e velocidade de rotação. Estas simulações permitiram estudar a forma como as forças axiais hidráulicas reagem a alterações nestas duas variáveis. Concluiu-se que a magnitude da força resultante aumenta com reduções do fluxo e com aumentos da velocidade de rotação. Adicionalmente, estimou-se que esta magnitude esteja compreendida, para condições normais de funcionamento da bomba, entre 0 e 1 N. Os efeitos individuais e as diferentes componentes da força resultante foram analisados detalhadamente, e as conclusões deste estudo mostraram-se coerentes com a literatura existente. Por último, o modelo foi validado através da comparação dos seus resultados com dados de CFD da ReinVAD LVAD, tendo-se concluído que os resultados eram coerentes em ambas as simulações.
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Kwant, Paul Barteld [Verfasser]. "Implantable electromechanical displacement blood pumps : systematic design and validation methods / vorgelegt von Paul Barteld Kwant." 2007. http://d-nb.info/989572781/34.
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Tallerico, Marco. "Fabrication and Characterization of a Microfluidic Device to Ultrapurify Blood Samples." Thesis, 2015. http://hdl.handle.net/10754/552418.
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The improvement of blood cell sorting techniques in recent years have attracted the attention of many researchers due to the possible benefits that these methods can lead in biology, regenerative medicine, materials science and therapeutic area. In this work a cell sorting technique based on filtration is described.
The separation occurs by means of a microfluidic device, suitably designed, manufactured and tested, that is connected to an external experimental set-up. The fabrication process can be divided in two parts: at first it is described the manufacturing process of a filtering membrane, with holes of specific size that allow the passage of only certain cell types. Following the microfluidic device is fabricated through the mechanical micromilling. The membrane and the microdevice are suitably bonded and tested by means of an external connection with syringe pumps that inject blood samples at specific flow rates. The device is designed to separate blood cells and tumor cells only by using differences in size and shape. In particular during the first experiments red blood cells and platelets are sorted from white blood cells; in the other experiments red blood cells and platelets are separated from white blood cells and tumor cells.
The microdevice has proven to be very efficient, in fact a capture efficiency of 99% is achieved. For this reason it could be used in identification and isolation of circulating tumor cells, a very rare cancer cell type whose presence in the bloodstream could be symptom of future solid tumor formation. The various experiments have also demonstrated that tumor cells survive even after the separation treatment, and then the suffered stress during the sorting process does not harm the biological sample.
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Chun-YiHsieh and 謝俊億. "Flow Study of Para-Aortic Blood Pump." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/72429148488886537016.
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碩士國立成功大學
航空太空工程學系碩博士班
100
Para-Aortic Blood Pump ( PABP ) is a novel left ventricular assist device. To ensure minimal thrombosis and hemolysis, four methods were used in this study. First, tracer particle visualization was used to reveal basic flow patterns. Second, dye dilution method results can identify if any residual non-replaceable fluid still remained inside the PABP. Third, dye washout method evaluated the surface washing effect. Last, particle image velocimetry (PIV) was applied to quantify the flow fields. The results of tracer particle visualization showed a counterclockwise vortex pattern inside the blood chamber of PABP. The results of dye dilution method proved good replacement that can prevent blood disease. The results of dye washout method indicated uniform washing on the wall. The results of PIV also showed a counterclockwise vortex pattern in PABP during diastole, and the maximum velocity was measured near 100 cm/sec. After analyzing the velocity, vorticity, and shear rate fields, one can conclude that both maximum velocity and shear rate happened right in the start of diastole. By calculating strain field of the flow, the maximum instaneous shear stress was found to be 0.4 N/m2, which was far less than the value of erythrocyte deformability: 50 N/m2 and the value of platelet activation: 10 N/m2. Therefore, the current PABP design is proven to be a low risk of thrombosis and hemolysis during diastole.
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Huang, Ching-Wen, and 黃敬文. "Traveling Wave Dielectrophoretic Pump for Blood Delivery." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/58186380680708334334.
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碩士國立臺灣大學
應用力學研究所
96
This thesis studies experimentally the traveling wave dielectrophoretic pump for delivering two-phase suspension medium, using human blood as an example. The pump is essentially a rectangular straight micro channel with a crosstie type electrode array built on one wall and operated under ac voltage with phase shift at neighboring electrodes. Both the conventional and traveling wave dielectrophoresis are generated. The negative conventional dielectrophoretic force repels the red blood cells from the electrode surface and the traveling wave dielectrophoretic force drives the cells along the direction of increasing phase. As the cells move, they drag their neighboring fluid (plasma), and the whole blood is delivered, after some sophisticated interaction of dielectrophoresis and fluid mechanics. The pump was fabricated using MEMS techniques and tested with different parameters of experiment, including the applied voltage, the operating frequency, the phase shift between neighboring electrodes, the number of electrodes, the dimensions of the channel, and the type of enhanced electrodes. It is found that the pump can attain a maximum pumping velocity at an intermediate frequency (about 20 MHz) and channel height (about 40 μm) with four phase signals. The steady average cell velocity can attain 15 μm/s for a pump with 1mm length and 24 electrodes, and operated with a four phase signal at 5 volts and 20 MHz. The pumping performance can be enhanced 2.4 times if two additional electrodes with appropriate applied voltages are added before the regular twDEP array.
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Huang, Ching-Wen. "Traveling Wave Dielectrophoretic Pump for Blood Delivery." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2907200816185000.
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Kuo, Yi-Chun, and 郭怡君. "Design and Analysis of axial flow blood pump." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/89406798337158329331.
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碩士崑山科技大學
機械工程研究所
103
Ventricular assist devices (VAD) are widely used to effectively improve the rate of patient survival, the waiting time of heart transplantation, and the quality of life in Europe, U.S.A. and Japan. The continuous pressurized and pulse type of left ventricular assist device (LVAD) are two popular designs. The working principle of continuous pressurized VAD is that by using the axial flow or centrifugal micro pump provide the pressure to make the blood flow through the left ventricular to aorta. This paper discussed and analyzed the functions of three different LVAD with axial flow micro pump. The specifications of the three LVADs are general traditional contacted bearing, 10 watt power, 7500~12500 rpm speed, 3~10 liter/min flow rate, and 100mmHg outlet pressure. The paper investigated the design parameters of the specifications to achieve the best functions LVAD and the results show the vales of these parameters are 5.48 watts power, 7000 rpm speed, and 9 liter/min flow rate under the constraint 100mmHg outlet pressure. The results are stratified with the desired requirement and better than the three exited LVADs. Furthermore, this study used a computational fluid dynamics software STAR-CD to simulate the flow field and performance with different compared design parameters. The Taguchi and the fuzzy methods are also used to analyze and design the optimum design parameters to find out the improved design of blades to achieve the optimum performance of flow field. Finally, the paper established a testing platform and proposed a completely pump performance testing process. The testing process can be used to measure the functions of practical LVAD in the future and verify the numerical simulation results proposed in this paper are feasible.
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Hung, Sun-wei, and 洪伸維. "Design and flow dynamic analysis of an axial blood pump." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/46377037762125988381.
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碩士淡江大學
水資源及環境工程學系碩士班
93
An axial blood pump is a driving mechanism of Left Ventricular Assist Device(LVAD) developed by TKU. The performance curves and the static wall pressure distributions of the axial blood pump are measured in in-vitro experiments. The results show that, at 7000 rpm, the axial blood pump can provide 100 mmHg pressure rise and 5 L/min flowrate which matching the design point. The flow fields of the upstream and downstream of the blood pump are qualitively analyzed by using the method of flow visualization. At design and off-design conditions, an annular region of reverse flow was commonly observed near the housing wall before the inlet stator. A small recirculation cell was observed behind the outlet stator tail region at design condition. We also utilized Laser Doppler Velocimetry (LDV) to measure the fluid velocities and turbulent intensities at the cross-sections of the upstream and downstream of the pump.
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Sun, Yun-Tin, and 孫妍婷. "Design and Testing of an Axial Blood Pump with Hydrodynamic Bearing." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/19075931369078290513.
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碩士淡江大學
水資源及環境工程學系碩士班
95
Cardiovascular disease is the major leading cause of death world wide. The success rate for heart replacement surgery exceeds 90 %, but the demand exceeds the supply. While waiting for a replacement, the patients must rely temporarily on artificial hearts or ventricular assist devices (VAD). The purpose of this study is to design an axial blood pump by using the hydrodynamic bearing theory, and simulate the initial design by the Computational Fluid Dynamics (CFD) method, which exceed the 5 L/min flow rate and 100 mm Hg pressure head. The fluid-film size between the rotor and stator is 50μm, which can account for lubrication and journal bearing. This pump was tested in distilled water which can produce a flow rate of 5 L/min with 50 mm Hg pressure head increase at 11,000 rpm. And it was tested in blood fluid analog which was 36% aqueous glycerin and 64% distilled water by volume. The result indicated that it can produce a flow rate of 5 L/min with 25 mm Hg pressure head increase at 9,000 rpm. Although the result does not reach the design object, but from the trend of pump performance curve, the flow rate and the pressure head all arise when the revolutions per minute increased.
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Day, Steven W. "Measurements of flow in a centrifugal blood pump using particle image velocimetry /." 2003. http://wwwlib.umi.com/dissertations/fullcit/3108769.
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Adnadjevic, Djordje. "Development of a suction detection system for a motorized pulsatile blood pump." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-08-1720.
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A computational model has been developed to study the effects of left ventricular assist devices (LVADs) on the cardiovascular system during a ventricular collapse. The model consists of a toroidal pulsatile blood pump and a closed loop circulatory system. Together, they predict the pump's motor current traces that reflect ventricular suck-down and provide insights into torque magnitudes that the pump experiences. In addition, the model investigates likeliness of a suction event and predicts reasonable outcomes for a few test cases. Ventricular collapse was modeled with the help of a mock circulatory loop consisting of a artificial left ventricle and centrifugal continuous flow pump. This study also investigates different suction detection schemes and proposes the most suitable suction detection algorithm for the TORVAD pump, toroidal left ventricular assist device. Model predictions were further compared against the data sampled during in vivo animal trials with the TORVAD system. The two sets of results are in good accordance.text
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Lee, Ping-hung, and 李炳宏. "Experimental Investigation of Wave Phenomena in Counter-pulsatile Para-aortic Blood Pump Support." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/87863268672574824736.
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碩士國立成功大學
航空太空工程學系碩博士班
97
In order to study the aortic flow characteristics when supported by a counter-pulsatile para-aortic blood pump (PABP), a specialized mock circulation test rig was constructed. This mock loop was designed using a hybrid circulation model concept, in which the aortic segment, where wave transport and flow convection are prominent, was represented by a silicone rubber while the rest systemic and pulmonary segments simulated by lumped resistors and compliance chambers. Hemodynamics associated with healthy, heart failure and PABP-supported conditions were simulated. The hemodynamic indices used to quantify the counter-pulsatile effectiveness consist of tension time index (TTI), endocardial viability ratio (EVR), mean systolic pressure (MSP), mean diastolic pressure (MDP), stroke volume (SV), left ventricular pressure-volume loop (LV P-V Loop), cardiac output (CO), stroke work (SW), and stroke work per unit cardiac output (SW/CO). It was found that pump inflation, when initiated right at the aortic valve closure instant, can result in the best diastolic augmentation. Pump deflation, however, can be operated within an adjacent time zone either prior to or after LV contraction, depending on whether minimized myocardial oxygen consumption or maximal cardiac output enhancement is desired. Deflation prior to LV ejection can result in increases in MDP (30%), EVR (60%), CO (20%), and decreases in TTI (16%) and MSP (15%). On the other hand, imminent deflation after LV contraction can elevate CO to around 30% with other counter-pulsatile indices slightly penalized. As judged by SW/CO, which indicates the external work delivered to blood stream per unit cardiac output, the optimal deflation occurs at two timings, one right on and another prior to the instant of LV ejection. The former is deemed better because CO enhancement at this instant is larger and the blood volume sucked from the downstream end organs is smaller. Wave intensity (WI) analysis was performed to analyze the pulse wave and the flow characteristics associated with different PABP deflation control timings. It was shown that PABP deflation induces two WI peaks on both forward- and backward-going wave spectra. The unloading strength or the LV ejection-induced WI is proportional to the lowering of the end-diastolic pressure. The backward unloading expansion wave, however, was annihilated as the deflation timing moved further into the LV ejection period. Deflation upon LV ejection was found the optimal unloading strategy which provided SW/CO reduction while avoided coronary regurgitation. Heart rate effect on pump effectiveness was also studied. Counter-pulsatile support enforced around 100 beats per minute gave the best performance as measured by the proposed hemodynamic indices and WI strengths.
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Lin, Ming-Da, and 林明達. "A Study and Development on thePerformance of Air Pump of Wrist Blood Pressure Monitor." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/65652695281221400748.
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碩士大同大學
機械工程學系(所)
92
Abstract High blood pressure has taken one of the top ten causes of death within the overall population locally. To prevent from high blood pressure, aside from the diet control, the adoption of handy and comprehensive electronic of no professional technique has become the must-have health care item of every household already. This research is aimed to the investigation about the function of air pump within the wrist blood pressure monitor。By using the L9(34) orthogonal arrays adopted by Taguchi, we make the settings for DC motor rotation, cam stroke, hardness of rubber piston, and superficial roughness of Pump Body, totally 4 factors, with 3 levels for experimenting separately. In reference with the experiment results, we found from the reaction charts that the main body of pump will come with the most evident influence for the superficial roughness of pump body; the cam-stroke and DC motor rotation come with the relatively low influence and the hardness of rubber piston actually exerts the least influence among all factors. Furthermore, the optimally conditioned combination for all factors are separately 12500rpm for DC motor rotation, 1.8mm for cam stroke, 50°for hardness of rubber piston and Ra 0.2 for the superficial roughness of pump body.
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Lin, Wei-Chieh, and 林瑋傑. "Design of An Inside-Human-Body Blood Pump Driver For A Wireless Bio-Diagnosis System." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/11887559296305419367.
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碩士國立臺灣大學
電子工程學研究所
96
This thesis focuses on driver for blood pump inside human body and which converts, inside human body, DC voltage into a high-voltage pulse for driving blood pump, so bio-diagnosis sensor can analyze blood. The structure of the driver is composed of ring oscillator, nonoverlapping clock generator, charge pump and level shifter, and it uses low dropout regulator (LDO) to reduce noise from the voltage source. First, some charge pump circuits are reviewed. After comparing strengths and weaknesses of the circuits, a suitable charge pump is chosen to design high-voltage pulse driver. Second, a new charge pump is designed for converting DC into high-voltage pulse. In addition, this charge pump is designed to re-develop a new high-voltage pulse driver. These two newly designed drivers have their own strengths and weaknesses in different applications. Then, these structures are modified taking the drivers’ influence on LDO into consideration. Finally, the circuit is simulated by HSPICE, the layout is designed, and the chip is tested.
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Untaroiu, Alexandrina. "LEV-VAD2 axial flow blood pump : optimized flow path design by means of computational fluid dynamics /." 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3225941.
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Medvitz, Richard B. Paterson Eric G. "Development and validation of a computational fluid dynamic methodology for pulsatile blood pump design and prediction of thrombus potential." 2008. http://www.etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-2449/index.html.
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