Design, Modeling, and Analysis of Piezoelectric-Actuated Device for Blood Sampling

In recent years, micro electro-mechanical system (MEMS)-based biomedical devices have been investigated by various researchers for biomedicine, disease diagnosis, and liquid drug delivery. The micropump based devices are of considerable significance for accurate drug delivery and disease diagnosis. In the present study, design aspects of the piezoelectric actuated micropump used for extraction of blood sample are presented. A pentagonal microneedle, which is an integral part of the micropump, was used to extract the blood volume. The blood was then delivered to the biosensor, located in the pump chamber, for diagnosis. The purpose of such low-powered devices is to get sufficient blood volume for the diagnostic purpose at the biosensor located within the pump chamber, with a minimum time of actuation, which will eventually cause less pain. ANSYS® simulations were performed on four quarter piezoelectric bimorph actuator (FQPB) at 2.5 volts. The modal and harmonic analysis were carried out with various load conditions for FQPB. The extended microneedle lengths inside the pump chamber showed improved flow characteristics. Enhanced volume flow rate of 1.256 µL/s was obtained at 22,000 Hz applied frequency at the biosensor location.

Optimization of the Beef Drying Process in a Heat Pump Chamber Dryer

Uneven air distribution in chamber dryers is a common and serious technological challenge. A study using CFD (Computer Fluid Dynamics) simulation, supported by measurements in a heat pump chamber dryer, confirmed irregular airflows. Performing simulations with modified settings and additional chamber modifications enabled the airflows to be visualized and optimized. It was shown that a modification of the chamber where a rotating disc had been used had a positive effect on the uniform distribution of air flows in the drying chamber. The modification significantly improves the energy balance of the beef drying process. Optimization of the process resulted in obtaining a high quality final product-beef jerky. This investigation proves that appropriate drying process control and introduced modifications enable high product quality and a safe level of water activity without the preservatives supplementation.

Research on Cavitation of the Rotating-Sleeve Distributing Flow System Considering Different Cam Groove Profiles

Reciprocating piston pumps are widely used in various fields, such as automobiles, ships, aviation, and engineering machinery. Conventional reciprocating piston pump distributing flow (RPPDF) systems have the disadvantages of a loose structure and low volumetric efficiency, as well as affected positively by the operating frequency. In this paper, a novel rotating-sleeve distributing flow (RSDF) system is presented for bridging these drawbacks, as well as structurally improved to overcome the inoperable and challenging problems in oil intake and discharge found in the experiment. Moreover, the Singhal cavitation model specifically for the RSDF system and four-cam groove profiles (CGPs) is established. To find the most suitable CGP to reduce the RSDF’s cavitation, the cavitation of the RSDF system was investigated, combining with simulations by taking into account the gap among the rotating sleeve, the pump chamber, and experiments on four presented CGPs. Simulation results based on vapor volume fraction, cavitation ratio, and volumetric efficiency show that the linear profile’s cavitation is the weakest. Finally, the correctness of the simulation is verified through orthogonal experiments. This research is of great significance to the further development of the RSDF system; more important, it has great potential to promote the reform of the RPPDF method.

Relationship between Axial Width and Flow Characteristics of Pump Chamber in Double Volute Centrifugal Pump

The axial width of pump chamber has a great influence on the flow characteristics of the pump chamber in the centrifugal pump. A single-stage single-suction double volute centrifugal pump with a semi-open impeller was selected as the object. For the 6 different pump chamber axial width, it was concluded that the pump chamber pressure at the different angles (0°, 90°, 180°, 270°) along the radial variation characteristics according to the contrast analysis of the pump cavity pressure field, velocity field distribution. The correlation between the pump chamber pressure and the impeller radius was revealed. The tangential velocity and radial velocity along the axial distribution curves were draw. The results show that when the axial width of pump chamber increases from 23.9 mm to 43.9 mm, the pressure value of the same radial position increases gradually. The radial pressure difference is decreasing. At the same axial width of pump chamber, the pressure mean increases along the radial approximately parabola. The tangential velocity of different angular directions has little difference in axial distribution. The mean of dimensionless tangential velocity in the turbulent core area decreases from 0.32 to 0.19 with the increasing of pump chamber axial width. The radial velocity varies is greatly along the axial direction. There are eddies at the directions of 0ånd 180°, but the mean of radial velocity in the turbulent core area is about 0. This research provides the reference for centrifugal pump hydraulic design, structural design and the accurate calculation of axial force.

Design, concept and first in-vitro results of the percutaneous, pulsatile left ventricular assist device-PERKAT LV

Introduction A very high morbidity and mortality is associated with cardiogenic shock due to left ventricular failure despite encouraging developments in interventional cardiology. Patients suffering from cardiogenic shock often require temporary mechanical circulatory support to stabilize organ perfusion. In addition, an increasing number of patients with complex multi-vessel diseases cannot undergo surgical myocardial revascularization as recommended by recent guidelines due to their comorbidities. Those patients could benefit from a protected PCI approach using a temporary mechanical assist device. The available LVAD systems have specific advantages and disadvantages. Purpose It was our aim to develop a percutaneous, pulsatile assist device that unloads the left ventricle in a physiologic way. Methods The PERKAT-LV (“PERkutane KATheterpumptechnologie”) device consists of a self-expanding nitinol pump chamber which is covered by foils. Those foils carry multiple outflow valves at the proximal part of the pump chamber. A flexible suction tube with a pigtail-shaped tip and inflow holes are attached to its distal part. The system is designed for 16F percutaneous implantation via the femoral artery. Pulling back the outer sheath unfolds the nitinol chamber in the descending aorta while the flexible suction tube bypasses the aortic arch and ascending aorta with its tip in the left ventricle. In the second implantation step, a standard IABP balloon is placed into the pumping chamber and is connected to an external IABP console. Balloon deflation generates a blood flow from the left ventricle into PERKAT LV. During balloon inflation, blood leaves the system through the outflow foil valves in the descending aorta. Positioning and schematic drawing of PERKAT-LV is demonstrated in Figure 1. Results Preliminary in-vitro studies using a prototype of the PERKAT LV device were performed. It was tested in different afterload settings (0, 40, 80 and 120 mmHg) using a standard 30 ccl IABP balloon and varying inflation/deflations rates (70, 80, 90, 100, 110 and 120/min). We detected flow rates ranging from 2.0 to 3.0 L/min depending on the afterload setting and inflation/deflation rate. Conclusion The novel percutaneously implantable and pulsatile working PERKAT-LV device offers left ventricular unloading and circulatory support of up to 3.0 L/min in a first feasibility study. At the moment, the system is extensively studied under in vitro conditions. First in vivo evaluation will follow in the near future. Based on the current results, we believe that the system is a promising novel approach for percutaneous application of temporary left ventricular mechanical support. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Federal Ministry of Education and Research

Development and Performance Research of New Small Displacement Pump with Solid Plunger and Non-coaxial Delivery Valve

Background: After the oilfield development coming into the middle and later periods, many oil wells only had liquid production less than 5m3 per day, therefore the present sucker-rod pumps didn’t satisfy the need for oilfield production. We revised all patents relating to small displacement pump and didn’t found any suitable pump for low production well. A new type of pump with small diameter was needed to design for solving the unbalance between the production and feed in lower production wells. Objective: o resolve the problems of supply and production imbalance of the low producing well, low pump efficiency and low system efficiency, a low displacement pump with non-coaxial delivery valve had been designed. Methods: This type pump adopted a solid plunger, and its delivery valve was not coaxial with the pump axial that would enhance its structural strength and been useful to reduce the partial flow loss of oil flowing through the static pump valve. At the down dead point of pump plunger, the delivery valve was located at the top of the pump chamber that was to the benefit of discharge of the gas and the oil from the pump chamber. The uneven distribution of the delivery hole was suitable for the wellhead diameter of the traditional oil wells. Results: The delivery valve was non-coaxial with the plunger that would decrease the flow loss through the passage and increase the pump efficiency. At the down-dead point, the plunger entered the extension nipple, and the delivery valve was located up the end of the solid plunger that promoted the remnant gas flowing out of the pump cylinder and decreased the effect of gas on the pump efficiency. Conclusion: As to this low displacement pump, we suggested: The suitable stroke was 2-3m; the stroke frequency was less than 3min-1. A reasonable range of submersible depth for low production well was 200-300m. It was used in the gas content well lower than 20%, else used the gas anchor firstly. The low displacement pump with non-coaxial delivery valve and solid plunger (NLDP) can improve the pump efficiency and reduce the polish rod load. At the same time, this NLDP provides new equipment for the production of the low oil well and improves the artificial lift design theory.

A Piezoelectric Resonance Pump Based on a Flexible Support

Small volume changes are important factors that restrict the improvement of the performance of a piezoelectric diaphragm pump. In order to increase the volume change of the pump chamber, a square piezoelectric vibrator with a flexible support is proposed in this paper and used as the driving unit of the pump. The pump chamber diaphragm was separated from the driving unit, and the resonance principle was used to amplify the amplitude of the pump diaphragm. After analyzing the working principle of the piezoelectric resonance pump and establishing the motion differential equation of the vibration system, prototypes with different structural parameters were made and tested. The results show that the piezoelectric resonance pump resonated at 236 Hz when pumping air. When the peak-to-peak voltage of the driving power was 220 V, the amplitude of the diaphragm reached a maximum value of 0.43933 mm, and the volume change of the pump was correspondingly improved. When the pump chamber height was 0.25 mm, the output flow rate of pumping water reached a maximum value of 213.5 mL/min. When the chamber height was 0.15 mm, the output pressure reached a maximum value of 85.2 kPa.

Civil Engineering Tool Kit for Making Perfect Ellipses of Desired Dimensions on Very Large Surfaces

If an ellipse is to be drawn of given dimensions there is no formula, method or set of calculations and procedure available with the help of which we can draw ellipse of given length and width on large ground. Whenever a field engineer is to start the work of an ellipse-shaped structure like elliptical conference hall, screening chamber and pump chamber in disposal work etc. he finds difficulty to give demarcation of the structure on the big surface of the ground. No procedure is available, even in Google. A set of formulas with calculations has been made with the help of which one can draw an true and perfect ellipse of given length and width on the large ground very easily so as to start the construction work of elliptical structure. Based on these formulas a civil Engineering tool kit has been made with the help of which we can make perfect ellipse of desired dimensions on very large surface. The Patent of the tool kit has been filed in Intellectual Property India with Patent Filing Number: 201611026153 and Patent Application Filing Date: 30.07.2016. An App named ‘KC’s Mesh Formula’ has also been made to ease the calculation work. This can be downloaded from Play Store. After adopting these formulas and tool kit, a field engineer will not face difficulty in drawing ellipse on the ground to start the work.

Research on Distribution of Flow Field and Simulation of Working Pulsation Based on Rotating-Sleeve Distributing-Flow System

To solve problems of leakage, vibration, and noise caused by disorders of flow field distribution and working pulsation in the rotating-sleeve distributing-flow system, governing equations of plunger and rotating sleeve and computational fluid dynamics (CFD) model are developed through sliding mesh and dynamic mesh technology to simulate flow field and working pulsation. Simulation results show that the following issues exist: obviously periodic fluctuation and sharp corner in flow pulsation, backward flow when fluid is transformed between discharge and suction, and serious turbulence and large loss in kinetic energy around the damping groove in transitional movements. Pressure in the pump chamber rapidly rises to 2.2 MPa involving over 10% more than nominal pressure when the plunger is at the Top Dead Center (TDC) considering changes about damping groove’s position and flow area in two transitional movements. Shortly pressure overshoot gradually decreases to a normal condition with increasing flow area. Similarly, pressure in the pump chamber instantaneously drops to a saturated vapor pressure −98.9 KPa when the plunger is at the Bottom Dead Center (BDC). With increasing flow area the overshoot gradually increases to the normal condition. This research provides foundations for investigating flow field characteristic and structure optimization of rotating-sleeve distributing-flow system.