Fluidic Control System Research Articles

Molecular system identification for enzyme directed evolution and design.

The rational design of chemical catalysts requires methods for the measurement of free energy differences in the catalytic mechanism for any given catalyst Hamiltonian. The scope of experimental learning algorithms that can be applied to catalyst design would also be expanded by the availability of such methods. Methods for catalyst characterization typically either estimate apparent kinetic parameters that do not necessarily correspond to free energy differences in the catalytic mechanism or measure individual free energy differences that are not sufficient for establishing the relationship between the potential energy surface and catalytic activity. Moreover, in order to enhance the duty cycle of catalyst design, statistically efficient methods for the estimation of the complete set of free energy differences relevant to the catalytic activity based on high-throughput measurements are preferred. In this paper, we present a theoretical and algorithmic system identification framework for the optimal estimation of free energy differences in solution phase catalysts, with a focus on one- and two-substrate enzymes. This framework, which can be automated using programmable logic, prescribes a choice of feasible experimental measurements and manipulated input variables that identify the complete set of free energy differences relevant to the catalytic activity and minimize the uncertainty in these free energy estimates for each successive Hamiltonian design. The framework also employs decision-theoretic logic to determine when model reduction can be applied to improve the duty cycle of high-throughput catalyst design. Automation of the algorithm using fluidic control systems is proposed, and applications of the framework to the problem of enzyme design are discussed.

Design of Passive Viscous Fluid Control Systems for Nonlinear Structures Based on Active Control

ABSTARCTA practical procedure is developed for the design of passive control systems using viscous fluid dampers for nonlinear structures. The design methodology takes advantage of the modification of the damping, strength, and stiffness properties of the structure to achieve the desired relative displacement and absolute acceleration response. For this purpose, a study of poles in the complex plane is used to determine the required changes in the dynamic properties of nonlinear structures. Furthermore, a relatively simple relation between the ductility demands of highly damped single- and multiple-degree-of-freedom (SDF and MDF respectively) systems is established to reduce the computational burden of the proposed design method.

Abstract 224: Critical variables for automated protein immunodetection using western blot

Abstract Reliable immunodetection of proteins is a critical step in the discovery of novel biomarkers. It is often performed manually. The immunodetection protocol consists of multiple steps including blocking of nonspecific binding sites, incubation using primary and secondary antibodies and extensive washing between steps that easily introduce bias and errors. The quality of results depends on multiple subjective and objective factors such as the qualification and technical skills of the personnel performing the assay and the accuracy of temporal and temperature control, especially during the immunodetection step. BlotCycler™, automated western blot processor, use fluidic control system that allows to eliminate the variability associated with immunodetection and to achieve higher sensitivity by optimized washing procedure. We used BlotCycler to analyze critical variables for immunodetection including temperature, incubation time and reagent mixing. Relatively small changes in duration and temperature of incubation significantly affect not only the intensity of signal but also the specificity of antibody interaction with antigen. Automated immunodetection at 4ºC significantly improve the specificity of detection and sensitivity that allows reproducible detection of low expressing proteins. Automated processing using BlotCycler allows optimization and control of critical variables leading to improved reproducibility and specificity of immunodetection and should be routinely used for biomarker candidate discovery and confirmation, reliable protein quantification, primary antibody specificity testing, and optimization of primary and secondary antibodies concentrations. Citation Format: Alexander Margulis, David P. Chimento, Russ Yukhananov. Critical variables for automated protein immunodetection using western blot [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 224. doi:10.1158/1538-7445.AM2017-224

Numerical Simulation to Determine Design Factors V-Block of Fluid Control System for Semi-Conductor Manufacturing Lines

Worldwide semi-conductor market has been growing from long time ago. Manufacturing lines of semi-conductors needs to handle several kinds of toxic gases. Especially, they have to be significantly accurately controlled in real time. This kind of toxic gas control system consists of many different kinds of part, for example, fittings, valves, tubes, filters and regulators. These parts obviously have to be precisely manufactured as well as corrosion resistant because they have to keep on controlling high pressure gases without any leakage. For this, surface machining and hardening technologies of metal block and metal gasket have to be studied. This study unfortunately depends upon various factors, for example, geometric shapes, part materials, surface hardening method and gas pressures. This study presented in the paper strongly concerned on a series of simulation processes about the differences between inlet and outlet pressures under considering several different fluid velocities, tube diameters, V-angles. In fact, it can be expected that this study will very helpful to determine important design factors as well as precisely manufacture these parts. For this, “Fluent” was used and simulation results were analyzed.

SlipChip Device for Digital Nucleic Acid Amplification.

Digital nucleic acid amplification (Digital NAA) quantifies nucleic acid by compartmentalizing a sample of DNA or RNA into a large number of discrete partitions and performing parallel nucleic acid amplification, such as polymerase chain reaction (PCR) or isothermal amplification reactions. With the counts of positive wells, total number of wells, and volumes of wells, the concentration of the target nucleic acid in the sample can be quantified. Digital NAA is considered increasingly powerful for ultra-sensitive detection and accurate quantification of nucleic acid for biological research and potentially medical diagnostics. Here, we describe glass SlipChip devices to perform digital NAA without cumbersome manual manipulation or complex fluidic control systems.

Experimental closed-loop control of separated-flow over a plain flap using extremum seeking

The lift coefficient of a configuration made of a flat plate with a trailing-edge plain flap is maximized at post-stall conditions by driving automatically the forcing frequency of a fluidic control system to an optimal value. The flap is equipped with pulsed blowing slots whose actuation frequency can be varied at constant actuation amplitude. The post-stall flow over the deflected flap is fully separated and organized around the natural vortex shedding at $$St=0.2$$ . It appears to be sensitive to the forcing frequency so that the lift coefficient is maximized if actuation is precisely the Strouhal number. Since this frequency depends on the flap deflection angle and the upstream velocity, an extremum seeking algorithm is implemented in order to drive the forcing frequency and thus guarantees that lift remains maximum whatever the geometric configuration is. Finally, a fuzzy-logic regulator is synthesized and integrated into the extremum seeking control scheme in order to speed up the convergence while maintaining stability and accuracy.

Active porous transition towards spatiotemporal control of molecular flow in a crystal membrane.

Fluidic control is an essential technology widely found in processes such as flood control in land irrigation and cell metabolism in biological tissues. In any fluidic control system, valve function is the key mechanism used to actively regulate flow and miniaturization of fluidic regulation with precise workability will be particularly vital in the development of microfluidic control. The concept of crystal engineering is alternative to processing technology in microstructure construction, as the ultimate microfluidic devices must provide molecular level control. Consequently, microporous crystals can instantly be converted to microfluidic devices if introduced in an active transformability of porous structure and geometry. Here we show that the introduction of a stress-induced martensitic transition mechanism converts a microporous molecular crystal into an active fluidic device with spatiotemporal molecular flow controllability through mechanical reorientation of subnanometre channels.

Development of a dynamic computational model of social cognitive theory.

Social cognitive theory (SCT) is among the most influential theories of behavior change and has been used as the conceptual basis of health behavior interventions for smoking cessation, weight management, and other health behaviors. SCT and other behavior theories were developed primarily to explain differences between individuals, but explanatory theories of within-person behavioral variability are increasingly needed as new technologies allow for intensive longitudinal measures and interventions adapted from these inputs. These within-person explanatory theoretical applications can be modeled as dynamical systems. SCT constructs, such as reciprocal determinism, are inherently dynamical in nature, but SCT has not been modeled as a dynamical system. This paper describes the development of a dynamical system model of SCT using fluid analogies and control systems principles drawn from engineering. Simulations of this model were performed to assess if the model performed as predicted based on theory and empirical studies of SCT. This initial model generates precise and testable quantitative predictions for future intensive longitudinal research. Dynamic modeling approaches provide a rigorous method for advancing health behavior theory development and refinement and for guiding the development of more potent and efficient interventions.

Microdevice for Separation of Circulating Tumor Cells using Embedded Magnetophoresis with V-shaped Ni-Co Nanowires and Immuno-nanomagnetic Beads

The novelty of this study resides in a 6”-wafer-level microfabrication protocol for a microdevice with a fluidic control system for the separation of circulating tumor cells (CTCs) from human whole blood cells. The microdevice utilizes a lateral magnetophoresis method based on immunomagnetic nanobeads with anti-epithelial cell adhesive molecule antibodies that selectively bind to epithelial cancer cells. The device consists of a top polydimethylsiloxane substrate for microfluidic control and a bottom substrate for lateral magnetophoretic force generation with embedded v-shaped soft magnetic microwires. The microdevice can isolate about 93% of the spiked cancer cells (MCF-7, a breast cancer cell line) at a flow rate of 40/100 mL/min with respect to a whole human blood/buffer solution. For all isolation, it takes only 10 min to process 400 mL of whole human blood. The fabrication method is sufficiently simple and easy, allowing the microdevice to be a mass-producible clinical tool for cancer diagnosis, prognosis, and personalized medicine.

Pneumatic sensors based on colliding curved wall jets

The paper discusses a novel version of fluidic sensors (in particular operating with air) based on a so far unknown aerodynamic principle—with two wall jets colliding head-on and both attached by the Coanda effect to the same cylindrical surface. The sensors may be particularly suitable for operation at low Reynolds numbers. Performed experimental investigation combined with numerical flowfield computations revealed several interesting aspects of the new approach. Among them, the most interesting is the discovery of symmetry breaking, which leads to existence of three alternative different stable flow regimes. This opens a possibility of designing fluidic tristable amplifiers and control systems operating with ternary logic.

Unique System for Underbalanced Drilling Using Air in the Marcellus Shale

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 171024, ’Unique System for Underbalanced Drilling by Use of Air in the Marcellus Shale,’ by Chris Maranuk, SPE, Ali Rodriguez, SPE, Joe Trapasso, SPE, and Joshua Watson, SPE, Weatherford, prepared for the 2014 SPE Eastern Regional Meeting, Charleston, West Virginia, USA, 21-23 October. The paper has not been peer reviewed. Air drilling has become popular in the Marcellus and Utica shale reservoirs because of its higher rate of penetration (ROP) and less resulting formation damage. A unique drilling system incorporating the use of downhole mud motors, electromagnetic (EM) measurement-while-drilling (MWD), and air hammers has been specifically designed and ruggedized to address downhole shock and vibration encountered in air drilling. Use of this system has resulted in significant reduction of nonproductive time (NPT). Introduction While seeking alternatives to increase ROP and reduce drilling costs, a few operators in the northeastern US implemented batch-drilling practices from pad locations. This provides an attractive alternative by allowing multiple wells to share the same surface location, effectively reducing footprint and environmental impact. Common well design uses streamlined well construction, where low-cost rigs can drill the tophole sections and larger, more-expensive rigs drill the curve and lateral sections. The typical well plan incorporates surface, intermediate, curve, and lateral sections that, combined, may exceed 18,000 ft. The lateral sections are the most critical and range between 2,000 and 8,000 ft, depending on formation and well geometry. The goal for close-proximity-well design is to minimize well-to-well interference and maximize reservoir exposure. Air drilling provides a significant decrease in hydrostatic pressure over common mud types, resulting in an increased ROP. Additionally, significantly better hole cleaning can be achieved because of the high air velocities used to drill the well. Finally, mud- and cuttings-handling costs can be reduced because there are no chemicals to absorb and no cuttings-cleaning requirements on virgin formations. Early tests of this application proved it to be a viable option for the Marcellus and the Utica fields. Initially, hammer bits were used for air drilling, but significant challenges involving directional control emerged as well-plan trajectories became more advanced. The development of ruggedized mud motors and MWD tools capable of handling these challenges, and the use of specialized fluid-control systems, eventually allowed more-conventional bottomhole assemblies (BHAs) to be successful when used for air drilling.

New Developments of Fluid Control System in the Fields of Medical and Welfare

New Developments of Fluid Control System in the Fields of Medical and Welfare

Characterization and Theoretical Analysis of Rapidly Prototyped Capillary Action Autonomous Microfluidic Systems

Capillary action arising from surface tension-based forces has been demonstrated to be an effective means of passively actuating various fluids through simple and sophisticated microfluidic channel networks. Systems based on this technique are advantageous compared with standard pumping strategies, as they have zero power requirements, are readily integrated into the overall fluidic chip design, and can be fabricated rapidly in a single manufacturing step. This paper comprehensively investigates time lapsed average velocity profiles of various capillary action microfluidic systems, including channels and pumping structures, and compares experimental data against prominent, competing, and flow-based theoretical models. We demonstrate that the average meniscus flow velocity of CO 2 laser ablated capillary systems can be adequately predicted and characterize smooth fluidic velocity profiles in simple microchannels and complex interlinking channel pump/filling structures. Such systems offer a useful, rapid, and low cost alternative to traditional fluidic actuation and flow control systems such as those found in on-chip based biological and chemical analysis.

Cavity-induced microstreaming for simultaneous on-chip pumping and size-based separation of cells and particles.

We present a microfluidic platform for simultaneous on-chip pumping and size-based separation of cells and particles without external fluidic control systems required for most existing platforms. The device utilizes an array of acoustically actuated air/liquid interfaces generated using dead-end side channels termed Lateral Cavity Acoustic Transducers (LCATs). The oscillating interfaces generate local streaming flow while the angle of the LCATs relative to the main channel generates a global bulk flow from the inlet to the outlet. The interaction of these two competing velocity fields (i.e. global bulk velocity vs. local streaming velocity) is responsible for the observed separation. It is shown that the separation of 5 μm and 10 μm polystyrene beads is dependent on the ratio of these two competing velocity fields. The experimental and simulation results suggest that particle trajectories based only on Stokes drag force cannot fully explain the separation behavior and that the impact of additional forces due to the oscillating flow field must be considered to determine the trajectory of the beads and ultimately the separation behavior of the device. To demonstrate an application of this separation platform with cellular components, smaller red blood cells (7.5 ± 0.8 μm) are separated from larger K562 cells (16.3 ± 2.0 μm) with viabilities comparable to those of controls based on a trypan blue exclusion assay.

Assessment of telemetry and fluidic control system used in the Medstream programmable infusion system: an in vivo and in vitro study.

The MedStream Programmable Infusion Pump, an intrathecal pump indicated for the treatment of chronic intractable pain and severe spasticity (CE-mark) or severe spasticity (US), has a highly accurate medication delivery (within 10% of the programmed flow rate) and is certified for use in 3-Tesla magnetic resonance imaging systems (conditional). Performance of the telemetric link between external control-unit and implanted pump was assessed in sheep (in vivo) up to 26 weeks, resulting in 1040 communication sessions. The telemetric communication envelope (communication distance and maximum antenna tilt angles) and communication duration were characterized in an in vitro test. Capacitance measurements of the piezoelectric actuator of the valve, valve flow rates, and leak rates were measured in an in vitro cyclic accelerated aging test to assess reliability of the valve over 6,200 k cycles. The pump was well tolerated in vivo; all communication sessions between control-unit and pump were successful (P = 6.889 × 10(-14)). Mean communication distance between pump and control-unit was 3.8 cm, with the maximum antenna tilt angles being 40° (θy) and 50° (θx) for all test cases; the maximum communication duration was 5.5 s. Capacitance measurements, flow rates, and leak rates were within ±10 % range up to 6,200 k cycles corresponding to approximately 10 times the valve cycles over the specified service life of the pump (8 years), except for one flow-rate value, which can be explained by the measurement setup. These results demonstrate the reliability of the telemetry link and piezoelectric valve system of the MedStream Programmable Infusion Pump.

Fluidic control of wake-flow behind a two-dimensional square back bluff body

This experimental study deals with wake-flow fluidic control behind a two-dimensional square back geometry positioned close to the ground. The fluidic control system is made of pulsed jets positioned at the upper edge of the model base. The objective of the fluidic action is to modify the wake-flow development, and as a consequence the static pressure distribution over the model base and hence the pressure drag. The main concern of this study is to determine to what extent the presence of a flow confined between the model and the floor influences the effectiveness of the control. Static pressure measurements at the model base and wake-flow characteristics derived from PIV measurements at a high acquisition frequency indicate global similarities between a case where an underbody flow exists and a case where this underbody flow is absent. For low actuation frequencies, discrepancies in the way the coherent structures due to the control develop in the shear layer appear.

Up-graded Control System of Liquid Nitrogen Management System of SST-1

Liquid Nitrogen (LN2) is used for 80 K thermal shield of Steady-state Super-conducting Tokamak (SST-1), Integrated Fluid Distribution and Control System, Current Feeder System and 80 K refrigerant in Helium Liquefier/Refrigerator. A dedicated storage and distribution system for LN2was installed at IPR. The present system includes 3-nos of storage tanks, sub-cooler dewar, vacuum jacketed cryo-lines and instrumentation. This system employs PLC based supervisory control system with smart process instrumentation. Considering nonupgradability and lack of reliability due to obsolesce of components of automation system and future plan of 80 K single phase distribution system for thermal shield of SST-1, new control system is required. Various control schemes are employed for sub-cooler dewar, evaporators and storage tanks. The up-graded control system will offer ease of operation with improved automation, better maintainability and reliability. This paper describes design and development of up-graded control system of LN2 system.

Enhancing visual acuity.

The Enhancing Visual Acuity (EVA) System (Dutch Ophthalmic Research Centre International B.V.) features a unique fluid control system - VacuFlow Valve Timing Intelligence (VTi®) - and represents the next-generation evolution of pump machines. VacuFlow VTi® overcomes the limitations of existing Venturi and peristaltic pumps and provides the potential to enable safer, faster, and more precise techniques. Alongside many other innovative and functional features, such as a light-emitting diode light source, integrated laser, high cutting speed with twin duty cycle cutting, automated infusion compensation, wireless foot pedal, phaco module with thresholding, and viscous fluid module, EVA could make a major contribution to advancing ophthalmology.

Shape memory alloy microvalves for a fluidic control system

This paper presents the design, fabrication, and performance of shape memory alloy (SMA) microvalves with a novel plug-in interface that enable arbitrary combinations and interchange of individual valve components in order to realize customized fluidic control systems. Actuation of the valves relies on a micromachined SMA foil, which is prestrained in order to adjust for a given flow, and pressure requirement. A demonstrator system is presented consisting of up to nine microvalves, flow channels and control electronics arranged in different functional layers that are stacked onto each other. The microvalves are designed for flow rates of 12.5 ml min−1 (water) in open state at a pressure difference of 200 kPa. Flow regulation is tested in closed-loop control mode using a flow sensor with a short time constant. The accuracy of flow control is in the order of 1.5%. The response times are below 24 ms.

An automatic enzyme immunoassay based on a chemiluminescent lateral flow immunosensor

Microfluidic integrated enzyme immunosorbent assay (EIA) sensors are efficient systems for point-of-care testing (POCT). However, such systems are not only relatively expensive but also require a complicated manufacturing process. Therefore, additional fluidic control systems are required for the implementation of EIAs in a lateral flow immunosensor (LFI) strip sensor. In this study, we describe a novel LFI for EIA, the use of which does not require additional steps such as mechanical fluidic control, washing, or injecting. The key concept relies on a delayed-release effect of chemiluminescence substrates (luminol enhancer and hydrogen peroxide generator) by an asymmetric polysulfone membrane (ASPM). When the ASPM was placed between the nitrocellulose (NC) membrane and the substrate pad, substrates encapsulated in the substrate pad were released after 5.3±0.3min. Using this delayed-release effect, we designed and implemented the chemiluminescent LFI-based automatic EIA system, which sequentially performed the immunoreaction, pH change, substrate release, hydrogen peroxide generation, and chemiluminescent reaction with only 1 sample injection. In a model study, implementation of the sensor was validated by measuring the high sensitivity C-reactive protein (hs-CRP) level in human serum.