Pump Parameters Research Articles

Monitoring left ventricular assist device parameters to detect flow- and power-impacting complications: a proof of concept.

The number of patients on left ventricular assist device (LVAD) support increases due to the growing number of patients with end-stage heart failure and the limited number of donor hearts. Despite improving survival rates, patients frequently suffer from adverse events such as cardiac arrhythmia and major bleeding. Telemonitoring is a potentially powerful tool to early detect deteriorations and may further improve outcome after LVAD implantation. Hence, we developed a personalized algorithm to remotely monitor HeartMate3 (HM3) pump parameters aiming to early detect unscheduled admissions due to cardiac arrhythmia or major bleeding. The source code of the algorithm is published in an open repository. The algorithm was optimized and tested retrospectively using HeartMate 3 (HM3) power and flow data of 120 patients, including 29 admissions due to cardiac arrhythmia and 14 admissions due to major bleeding. Using a true alarm window of 14 days prior to the admission date, the algorithm detected 59 and 79% of unscheduled admissions due to cardiac arrhythmia and major bleeding, respectively, with a false alarm rate of 2%. The proposed algorithm showed that the personalized algorithm is a viable approach to early identify cardiac arrhythmia and major bleeding by monitoring HM3 pump parameters. External validation is needed and integration with other clinical parameters could potentially improve the predictive value. In addition, the algorithm can be further enhanced using continuous data.

Theoretical analysis about model simplifications and boundary conditions on two-phase flow instability of parallel heated tube systems

Flow instability may happen in both subcritical two-phase flow boiling systems (such as U tube natural circulation steam generator of Pressurized Water Reactor, once through steam generator of High-Temperature Gas-Cooled Reactor, etc) and supercritical evaporation systems. In previous theoretical researches, the model of a single heated tube (SHT) with constant pressure drop boundary condition (ConPD) was always used to investigate the system stability. However, in real applications, there are usually multiple parallel heated tubes (MHT) and unheated connection regions before the branch heated tubes. The system is usually driven by a pump, and there is always a long unheated main pipe and throttling between the heated tubes (boiler or steam generator) and the pump. However, there lacks rigorous analysis about the effects of these model simplifications and boundary conditions. Take superheated two-phase flow boiling systems as examples, the theoretical models with different flow-driven boundary conditions (ConPD, constant mass flow rate (ConMF), and pump driven (PumpD)), different numbers of heat tubes (SHT, MHT), with or ignoring the unheated region (UHR), with or ignoring the bypass of a pump, with identical or un-identical geometry parameters and operation parameters are established. Linear ordinary differential equations describing the instability are obtained. Eigenvalues of the coefficient matrix of linear ordinary differential equations, and the property of the block matrix and the similarity matrix are used to analyze the effects of the above boundary conditions and model simplifications on the system stability. Two new dimensionless numbers, dimensionless pump number (Npump) and dimensionless bypass number (Nbypass), are proposed to describe the effect of pump and its bypass on stability quantitatively. The effect of the pump bypass on the stability can be attributed to the decrease of Npump. No matter ConPD or PumpD is adopted, SHT considering UHR is proved to be more stable than SHT ignoring UHR. No matter UHR is considered or ignored, SHT with PumpD is proved to be more stable than SHT with ConPD. No matter UHR of MHT at the main pipe is considered or ignored, the stability of MHT with ConPD or ConMF or PumpD is proved to be the same as that of SHT with ConPD ignoring UHR. When ConPD ignoring UHR is adopted, the stability of MHT with un-identical geometry and operation parameters is proved to be the same as that of its most unstable heated tube. The above conclusions about the effect of model simplification and boundary condition are obtained from superheated two-phase flow boiling systems, they also hold for saturated two-phase flow boiling systems and supercritical evaporation systems.

Correlation-Enhanced Interaction of a Bose-Einstein Condensate with Parametric Magnon Pairs and Virtual Magnons.

Nonlinear interactions are crucial in science and engineering. Here, we investigate wave interactions in a highly nonlinear magnetic system driven by parametric pumping leading to Bose-Einstein condensation of spin-wave quanta-magnons. Using Brillouin light scattering spectroscopy in yttrium-iron garnet films, we found and identified a set of nonlinear processes resulting in off-resonant spin-wave excitations-virtual magnons. In particular, we discovered a dynamically strong, correlation-enhanced four-wave interaction process of the magnon condensate with pairs of parametric magnons having opposite wave vectors and fully correlated phases.

HeartMate 3 Snoopy: Noninvasive cardiovascular diagnosis of patients with fully magnetically levitated blood pumps during echocardiographic speed ramp tests and Valsalva maneuvers

The HeartMate 3 (HM3) left ventricular assist device (LVAD) has demonstrated excellent clinical outcomes; however, pump speed optimization is challenging with the available HM3 monitoring. Therefore, this study reports on clinical HM3 parameters collected with a noninvasive HM3 monitoring system (HM3 Snoopy) during echocardiographic speed ramp tests and Valsalva maneuvers. In this prospective, single-center study, the HM3 data communication between the controller and pump was recorded with a novel data acquisition system. Twelve pump parameters sampled every second (1Hz) and clinical assessments (echocardiography, electrocardiogram (ECG), and blood pressure measurement) during speed ramp tests were analyzed using Pearson's correlation (r, median [IQR]). The cause for the occurrence of pulsatility index (PI)-events during ramp speed tests and valsalva maneuvers was investigated. In 24 patients (age: 58.9±8.8years, body mass index: 28.1±5.1kg/m2, female: 20.8%), 35 speed ramp tests were performed with speed changes in the range of ±1000rpm from a baseline speed of 5443±244rpm. Eight HM3 pump parameters from estimated flow, motor current, and LVAD speed together with blood pressure showed positive collinearities (r=0.9 [0.1]). Negative collinearities were observed for pump flow pulsatility, pulsatility index, rotor noise, and left ventricular diameters (r=-0.8 [0.1]), whereas rotor displacement and heartrate showed absence of collinearities (r=-0.1 [0.08]). In this study, the HM3 Snoopy was successfully used to acquire more parameters from the HM3 at a higher sampling rate. Analysis of HM3 per-second data provide additional clinical diagnostic information on heart-pump interactions and cause of PI-events.

Physician Preferences when Selecting Candidates for Lower-Quality Kidney Offers.

In the United States, more than 50% of kidneys in the lowest 15% quality range (those with Kidney Donor Profile Index >85) are discarded. Studies suggest that using more of these kidneys could benefit patients waiting for a transplant. This study assesses the trade-offs physicians make when selecting recipients for lower-quality kidneys. A discrete choice experiment (DCE) was administered to surgeons and nephrologists in the United States who are involved in kidney acceptance decisions. The DCE presented kidneys that varied in terms of Kidney Donor Profile Index, expected cold ischemia time, donor age, pump parameters, serum creatinine levels, glomerulosclerosis, donor diabetes status, and whether donation was made after circulatory death. Candidate characteristics included recipients' age, diabetes history, time on dialysis, ejection fraction, HLA mismatch, calculated panel reactive antibody, and Karnofsky performance score. Regression analysis was used to estimate acceptability weights associated with kidney and recipient characteristics. A total of 108 physicians completed the DCE. The likelihood of acceptance was significantly lower with deterioration of kidney quality, expected cold ischemia time at transplantation, and missing biopsy and pump information. Acceptance was prioritized for patients who were higher on the waiting list, younger recipients, those who have spent less time on dialysis, and those without a history of diabetes. Performance status (Karnofsky score) and calculated panel reactive antibody also had a statistically significant but smaller association. Finally, ejection fraction had a marginally significant association, and HLA match had no significant association with the acceptance of marginal kidneys. A group of respondents were found to be primarily concerned about cold ischemia time. In this DCE, physicians considered the recipient characteristics that inform expected post-transplant survival score when they decided whether to accept a marginal kidney for a given recipient.

Heat pump integration in non-continuous industrial processes by Dynamic Pinch Analysis Targeting

A key strategy for the transition towards a low-carbon economy is the electrification of industrial heat. Heat pumps can recover and upgrade excess or waste heat. They present a highly efficient component to decarbonize process heating. In Pinch Analysis, most approaches to design the heat recovery system as well as the utility system are based on a single operating point or a couple of operating point. In the past, this was due to the lack of temporally detailed process data. However, the available process data is expected to increase drastically by the use of transient process simulation models. Thus, a method is needed which interprets the data correctly and assists with design choices.This study proposes a methodology for the design and sizing of a heat pump based on the simulated annual process data of an industrial process. Three approaches are explored: (1) the conventional approach for heat pump integration by application of the Time Average Model (TAM), (2) an approach that investigates the optimal heat pump parameters for each data point by the principles of Pinch Analysis and mathematical optimization and (3) an optimization method, which considers the entire annual process data as well as thermo-economic objectives such as net present value (NPV) and internal rate of return (IRR).The new methodology compared to the conventional TAM approach is able to design a 33 % smaller heat pump, which reduces the annual operating cost by an additional 2.2 %. The NPV and IRR are more than tripled.

Intracranial Pressure Evaluation in Swine During Full-Endoscopic Lumbar Spine Surgery

Neurological complications during full-endoscopic spine surgery (FESS) might be attributed to intracranial pressure (ICP) increase due to continuous saline infusion (CSI). Understanding CSI and ICP correlation might modify irrigation pump usage. This study aimed to evaluate invasive ICP during interlaminar FESS; correlate ICP with irrigation pump parameters (IPPs); evaluate ICP during saline outflow occlusion, commonly used to control bleeding and improve the surgeon's view; and, after durotomy, simulate accidental dural tear. Five swine were monitored, submitted to total intravenous anesthesia, and positioned ventrally. A parenchymal catheter was installed through a skull burr for ICP monitoring. Lumbar interlaminar FESS was performed until exposure of neural structures. CSI was used within progressively higher IPPs (A [60 mm Hg, 350 mL/minute] to D [150 mm Hg, 700 mL/minute]), and ICP was documented. During each IPP, different situations were grouped: intact dura with open channels (A1-D1) or occlusion test (A2-D2); dural tear with open channels (Ax1-Dx1) or occlusion test (Ax2-Dx2). ICP <20 mm Hg was defined as safe. Basal average ICP was 8.1 mm Hg. Adjustment in total intravenous anesthesia or suspension of tests was necessary due to critical ICP or animal discomfort. It was safe to operate with all IPPs with opened drainage channels (A1-D1) even with dural tear (Ax1-Dx1). Several occlusion tests (A2-D2, Ax2-Dx2) caused ICP increase (e.g., 86.1 mm Hg) influenced by anesthetic state and hemodynamics. During FESS, CSI might critically raise ICP. Keeping drainage channels open, with ideal anesthetic state, ICP remains safe even with high IPPs, despite dural tear. Drainage occlusions can quickly raise ICP, being even more severe with higher IPPs. Total intravenous anesthesia may protect from ICP increase and may allow longer drainage occlusion or higher IPPs.

Effects of pump parameters on the oil absorption characteristics of bidirectional involute internal gear pumps

The symmetrical oil suction and discharge chambers and the reversing rotation condition of bidirectional involute internal gear pumps result in low oil absorption capacity and flow pulsation due to cavitation. However, efforts to address these issues suffer from an incomplete understanding of the effects of oil properties, suction chamber volume, suction pressure, and rotational speed on the oil absorption capacity and cavitation characteristics of these pumps. The present work addresses this issue by conducting detailed computational fluid dynamics (CFD) simulations. The results of analysis demonstrate that the degree of cavitation caused by changes in the mass fraction of dissolved gas in the oil is positively correlated with flow pulsation, while the degree of cavitation caused by changes in the suction port size, suction pressure, and rotational speed is negatively correlated with flow pulsation. The degree of cavitation in the oil suction cavity initially increases as the mass fraction of dissolved gas in the oil increases, and then decreases. The rotational speed exhibits a critical value, where the oil absorption capacity increases with increasing rotational speed below the critical value, and decreases with increasing rotational speed above the critical value. The results of this research are expected to be of great significance for guiding improvements in the design of bidirectional involute internal gear pumps and the determination of critical working conditions.

Effect analysis of centrifugal pump parameters optimization design on performance

Under the background of energy-saving priority and efficient use of energy, centrifugal pump, as a kind of energy conversion equipment in modern industry and agriculture with liquid as the medium, plays an important role in many occasions. Optimization of performance parameters of centrifugal pump can improve efficiency and save energy. Important parameters include the number of blades and structural optimization of blade tail, etc. These parameters are often selected according to experience in actual production, which lacks accuracy and persuasiveness. The influence of different blade numbers and structural designs on cavitation performance and efficiency of the pump is studied, and the characteristic curve of the pump is drawn. The blade performance is evaluated comprehensively according to the pressure distribution, flow condition, cavitation degree and velocity diagram under different blade numbers, and the conclusion is drawn. The efficiency of the four-blade pump is 6.96% higher than that of the original six-blade pump, 1.96% higher than that of the three-blade pump, and 5.11% higher than that of the five-blade pump. The optimization results are obvious, which provides reference for the determination and setting of the number of centrifugal pumps.

Less Invasive Left Ventricular Assist Device Implantation Is Safe and Feasible in Patients With Smaller Body Surface Area.

Smaller body surface area (BSA) frequently precludes patients from left ventricular assist device (LVAD) therapy. We sought to investigate the clinical outcomes in patients with small BSA undergoing less invasive LVAD implantation. We conducted a retrospective review of 216 patients implanted with HeartMate 3 LVAD (Abbott, Chicago, IL) via less invasive surgery at our institution. Patients were dichotomized based on their preimplant BSA for comparison between small BSA (≤1.8 m2) and normal/large BSA (>1.8 m2). We analyzed patient perioperative characteristics and outcomes. In our study, small BSA was found in 32 patients (14.8%), while 184 patients (85.2%) had normal/large BSA. Women were more prevalent in the small BSA group (50.0% vs 13.0%, P < 0.001). Preoperative and intraoperative data showed comparable results. Major complications and hospital length of stay did not differ by BSA group. Patients with smaller BSA had significantly decreased pump parameters at discharge, including LVAD flow (4.11 ± 0.49 vs 4.60 ± 0.54 L/min, P < 0.001) and pump speed (5,200 vs 5,400 rpm, P < 0.001). Survival to discharge and within 6 months after implantation were similar between the groups. Our study results suggest that less invasive HeartMate 3 implantation can be safely performed and demonstrates equivalent outcomes in patients with smaller body habitus. Randomized trials are required to confirm our data.

Circadian rhythms in pump parameters of patients on contemporary left ventricular assist device support.

Algorithms to monitor pump parameters are needed to further improve outcomes after left ventricular assist device (LVAD) implantation. Previous research showed a restored circadian rhythm in pump parameters in patients on HeartWare (HVAD) support. Circadian patterns in HeartMate3 (HM3) were not studied before, but this is important for the development of LVAD monitoring algorithms. Hence, we aimed to describe circadian patterns in HM3 parameters and their relation to patterns in heart rate (HR). 18 HM3 patients were included in this study. HM3 data were retrieved at a high frequency (one sample per 1 or 2 h) for 1-2 weeks. HR was measured using a wearable biosensor. To study overall patterns in HM3 parameters and HR, a heatmap was created. A 24-h cosine was fitted on power and HR separately. The relationship between the amplitude of the fitted cosines of power and HR was calculated using Spearman correlation. A lower between patient variability was found in power compared with flow and PI. 83% of the patients showed a significant circadian rhythmicity in power (p < 0.001-0.04), with a clear morning increase. All patients showed significant circadian rhythmicity in HR (p < 0.001-0.02). The amplitudes of the circadian rhythm in power and HR were not correlated (Spearman correlation of 0.32, p = 0.19). A circadian rhythm of pump parameters is present in the majority of HM3 patients. Higher frequency pump parameter data should be collected, to enable early detection of complications in the future development of predictive algorithms.

Solid-Solid Interfacial Contact of Tubing Walls Drives Therapeutic Protein Aggregation During Peristaltic Pumping

Peristaltic pumping during bioprocessing can cause therapeutic protein loss and aggregation during use. Due to the complexity of this apparatus, root-cause mechanisms behind protein loss have been long sought. We have developed new methodologies isolating various peristaltic pump mechanisms to determine their effect on monomer loss. Closed-loops of peristaltic tubing were used to investigate the effects of peristaltic pump parameters on temperature and monomer loss, whilst two mechanism isolation methodologies are used to isolate occlusion and lateral expansion-relaxation of peristaltic tubing. Heat generated during peristaltic pumping can cause heat-induced monomer loss and the extent of heat gain is dependent on pump speed and tubing type. Peristaltic pump speed was inversely related to the rate of monomer loss whereby reducing speed 2.0-fold increased loss rates by 2.0- to 5.0-fold. Occlusion is a parameter that describes the amount of tubing compression during pumping. Varying this to start the contacting of inner tubing walls is a threshold that caused an immediate 20-30% additional monomer loss and turbidity increase. During occlusion, expansion-relaxation of solid-liquid interfaces and solid-solid interface contact of tubing walls can occur simultaneously. Using two mechanisms isolation methods, the latter mechanism was found to be most destructive and a function of solid-solid contact area, where increasing the contact area 2.0-fold increased monomer loss by 1.6-fold. We establish that a form of solid-solid contact mechanism whereby the contact solid interfaces disrupt adsorbed protein films is the root-cause behind monomer loss and protein aggregation during peristaltic pumping.

Instabilities near Ultrastrong Coupling in a Microwave Optomechanical Cavity.

With artificially engineered systems, it is now possible to realize the coherent interaction rate, which can become comparable to the mode frequencies, a regime known as ultrastrong coupling (USC). We experimentally realize a cavity-electromechanical device using a superconducting waveguide cavity and a mechanical resonator. In the presence of a strong pump, the mechanical-polaritons splitting can nearly reach 81% of the mechanical frequency, overwhelming all the dissipation rates. Approaching the USC limit, the steady-state response becomes unstable. We systematically measure the boundary of the unstable response while varying the pump parameters. The unstable dynamics display rich phases, such as self-induced oscillations, period-doubling bifurcation, and period-tripling oscillations, ultimately leading to the chaotic behavior. The experimental results and their theoretical modeling suggest the importance of residual nonlinear interaction terms in the weak-dissipative regime.

An energy-efficient pumping system for sustainable cities and society: Optimization, mathematical modeling, and, impact assessment

In this research work, we have focused on one of the reasons called drawdown (difference between static and pumping heads) for getting maximum efficiency. Therefore, various mechanical attachments have been designed and fabricated for performance evaluation. Since pump performance and drawdown are inversely related, the primary goal is to reduce drawdown as much as possible. The effect of various types of mechanical attachments on pump performance is investigated in this research work. Three bowl-type mechanical attachments can be integrated at once and can increase efficiency by up to 58%, which is 8% more than utilizing no attachment. Additionally, the impact of bore well diameter on pump performance has been studied. In addition, the impact of applying mechanical attachment at two pumping sites has been investigated, and a considerable amount of energy savings has been found. The response surface methodology (RSM)-based optimization of the various input parameters has also been examined. It was found that the maximum 62.04 % could be achieved through a head of 66.5 m, a discharge of 0.012 m3/s, an input power of 12,605 W, and a bore well diameter of 0.215054 m, having three bowl-type mechanical attachments at a time. The mathematical modeling was also performed using analysis of variance (ANOVA) and formulated some equations for pumping efficiency with various pumping input parameters. Since there is very little variation between actual and anticipated performance, it can be used to evaluate the pumping system’s performance in relation to various input parameters. As a result, maintaining sustainable cities and societies might greatly benefit from the energy-efficient pumping system.

Prediction of centrifugal pump performance parameters based on a multilayer hybrid model

The present paper presents a multilayer hybrid model for sensorless measurement of pump operating status, with the objective of enabling safe and stable operations while reducing energy losses. The model takes easily measurable variables such as rotational frequency and valve opening as input features to predict the performance parameters of the centrifugal pump. By integrating just-in-time learning (JITL) with Gaussian process regression (GPR) and leveraging the unique probability features of GPR, a just-in-time-learning GPR (JGPR) is developed to extract valuable feature information. The JGPR sequentially predicts the flow rate, coefficient for dynamic head, and shaft power. The predicted values are extended to other input features, which can accurately capture the characteristics of the centrifugal pump and effectively replace the process of acquiring process parameters through sensors. Finally, the mechanism model is integrated into the multilayer JGPR model to calculate the performance parameters of centrifugal pump. The validation results indicate a strong agreement between predicted and experimental results, with predicted meeting performance parameters all engineering requirements. Compared to a single model, the multilayer hybrid model significantly improves the reliability of predictions, demonstrating the feasibility of using this approach to predict performance parameters. This research provides valuable insights into the measurement of sensorless pump operating states, enabling safe and efficient operation in complex conditions.

On the correlation between proppant addition strategy and distribution

The proppant pumping schedule is critical in hydrofracking because it affects both fluid flow and proppant transport. In the study reported here, a validated CFD-DEM model was employed to study the impact of proppant pumping strategy on proppant transport in a rough rock fracture. Three injection sequences of multi-sized proppants were applied while varying other pumping parameters including injection velocity, the size of large proppants, and the concentration of large proppants. Both vertically and horizontally sheared rough, joint rough, and smooth fractures were adopted to enable a better understanding of the impact caused by fracture geometry. The results reveal that the variation in proppant distribution caused by adjusting the pumping sequence or a single pumping parameter is not absolute. Rather than pumping parameters, the final proppant distribution is governed directly by two competing effects caused by the alteration of proppant bridging effect. It was also found that the proppant volume retained in fractures is under-estimated if the CFD mesh size is too small to reach three times the particle size. The lateral conveyance of proppant could be enhanced by considering the Saffman lift force in CFD-DEM modeling. The results of this study shed light on proppant transport in hydraulic fractures under various addition strategies, which will assist the optimization of fracturing treatments in unconventional reservoirs.

Soft computing-based predictive modeling of flexible electrohydrodynamic pumps

Flexible electrohydrodynamic (EHD) pumps have been developed and applied in many fields due to no transmission structure, no wear, easy manipulation, and no noise. Physical simulation is often used to predict the output performance of flexible EHD pumps. However, this method neglects fluid–solid interaction and energy loss caused by flexible materials, which are both difficult to calculate when the flexible pumps deform. Therefore, this study proposes a flexible pump output performance prediction using machine learning algorithms. We used three different types of machine learning: random forest regression, ridge regression, and neural network to predict the critical parameters (pressure, flow rate, and power) of the flexible EHD pump. Voltage, angle, gap, overlap, and channel height are selected as five input data of the neural network. In addition, we optimized essential parameters in the three networks. Finally, we adopt the best predictive model and evaluate the significance of five input parameters to the output performance of the flexible EHD pumps. Among the three methods, the MLP model has exceptionally high accuracy in predicting pressure and flow. Our work is beneficial for the design process of fluid sources in flexible soft actuators and soft hydraulic sources in microfluidic chips.

Hydrodynamic Characteristic Analysis and NSGA-II Optimization of a Vacuum Fish Pump

The fish pump is an important piece of power equipment for aquaculture, especially for deep-sea engineering vessels and cage culture. Fish pump research focuses on reducing fish body damage, improving survival rates, and increasing fish lifting efficiency. The research object in this paper is a new type of vacuum fish pump, with the aim of improving the hydraulic performance of the vacuum fish pump and reducing the damage to the fish body. The dependent variables include the dynamic change process of the flow state and flow field under diachronic conditions, the fluid simulation analysis of the vacuum pump body and the flow channel structure, the inlet flow rate of the fish pump, the negative pressure of the pipeline, and the impact force of the water flow on the inner wall of the tank. The independent variables include the operating conditions of the pump body and the fish pump. The Latin hypercube sampling method is used to extract 167 sets of calculation models for the independent variables, and multi-objective optimization is performed based on the NSGA-II algorithm for the hydrodynamic performance of the fish pump. On the basis of ensuring the fish body damage rate, the structural parameters of the vacuum fish pump with the optimal hydrodynamic performance under 167 sets of parameter values were obtained. The optimized parameters were then entered into the solver again, and the results showed that, in the optimal structural parameters under certain conditions, the direction of the incident water flow in the vacuum fish pump tank is close to the upper end of the tank body, which will reduce the speed of the fish-water mixed flow when entering the tank, thereby reducing the collision damage to the fish body. Currently, the water flow velocity at the water inlet is about 2.5 m/s, and the negative pressure value distribution gradient between the tank body and the water inlet pipeline is quite consistent, which can achieve good fish suction and fish lifting effects.

Longitudinal analysis of pump parameters over long-term support with the HeartMate 3 left ventricular assist device.

Recurrence of heart failure emerged as the main cause of long-term mortality in patients implanted with the HeartMate 3 (HM3) left ventricular assist device (LVAD). We aimed at deriving a possible mechanistic rationale of clinical outcomes and analyzed longitudinal changes in pump parameters over prolonged HM3 support to investigate long-term effects of pump settings on left ventricular mechanics. Data on pump parameters (i.e. pump speed, estimated flow, and pulsatility index) were prospectively recorded in consecutive HM3 patients following postoperative rehabilitation (baseline) and then at 6, 12, 24, 36, 48, and 60 months of support. Data of 43 consecutive patients were analyzed. Pump parameters were set according to regular patients' follow-up, including clinical and echocardiographic assessment. We recorded a significant progressive increase in pump speed over the course of support: from 5200 (5050-5300) rpm at baseline to 5400 (5300-5600) rpm at 60 months of support ( P = 0.0007). Consistently with the increase in pump speed, a significant increase in pump flow ( P = 0.007) and a decrease in pulsatility index ( P = 0.005) were also recorded. Our results reveal unique features of the HM3 on left ventricular activity. The need for progressive increase in pump support suggests indeed a lack of recovery and worsening of left ventricular function, which emerge as a possible mechanistic rationale of heart failure related mortality in HM3 patients. New algorithms to optimize pump settings should be envisioned to further improve LVAD-LV interaction and, ultimately, clinical outcomes in the HM3 population. https://clinicaltrials.gov/ct2/show/NCT03255928. NCT03255928.

Automated methodology of calculating parameters for non-traditional technology of heating mode of hydro-storage power plant station

Purpose. Justification of the rational parameters of heat pumps and heat accumulators to ensure the efficient operation of the hydro storage power plant (HSPP) in the heating mode. Development of an automated methodology for calculating rational parameters for a complex system of a hydro storage power plant operating in heating mode. Methodology. Mathematical analysis and modeling. Findings. Using the developed automated calculation method, it was analyzed and determined that passing through the heat pump the full flow of water passing through the hydro unit is impractical and ineffective, because the energy consumption in the heat pump compressor is many times higher than the consumption of the hydro unit in pumping mode, which devalues the proposed measure as an energy-saving measure. The use of a heat pump and a heat accumulator at the hydro storage power plant for hot water supply needs will save a third of conventional fuel costs compared to a boiler unit. The developed automated technique allows to calculate the limit and rational values of design and operating parameters of the heat pump and heat accumulator, which ensure the heating mode of operation of the hydro storage power plant to meet the needs of hot water supply. Originality. An automated methodology for calculating the parameters of a complex system has been developed for the hydro storage power plant operating in heating mode. The concept of the maximum heat capacity of the hot water supply of the heat pump is introduced. The concept of the rational heat capacity of the hot water supply of the heat pump is introduced. In addition to the maximum heat capacity and the rational heat capacity modes, the developed method allows you to calculate all the parameters of the heat pump and heat accumulator, which provide the heating mode of the hydro storage power plant, for arbitrary values of the thermal power of hot water supply, with further comparison and analysis of the investigated modes and the selection of the most promising one. Practical value. The technology of using a heat pump and a heat accumulator to transfer the operation of the hydro storage power plant to the heating mode (hot water supply of residential buildings) is substantiated. The possibility of saving conditional fuel when applying the proposed technology is proven.