Fluidic Control System Research Articles

Low porosity, high areal-capacity Prussian blue analogue electrodes enhance salt removal and thermodynamic efficiency in symmetric Faradaic deionization with automated fluid control

Prussian blue analogues (PBAs) show great potential for low-energy Faradaic deionization (FDI) with reversible Na-ion capacity approaching 5 M in the solid-state. However, past continuous-flow demonstrations using PBAs in FDI were unable to desalinate brackish water to potable levels using single-pass architectures. Here, we show that recirculation of effluent from a symmetric cation intercalation desalination cell into brine/diluate reservoirs enables salt removal exceeding 80% at thermodynamic efficiency as high as 80% when cycled with 100 mM NaCl influent and when controlled by a low-volume, automated fluid circuit. This exceptional performance is achieved using a novel heated, alkaline wet phase inversion process that modulates colloidal forces to increase carbon black aggregation within electrode slurries to solidify crack-free, high areal-capacity PBA electrodes that are calendered to minimize cell impedance and electrode porosity. The results obtained demonstrate the need for co-design of auxiliary fluid-control systems together with electrode materials to advance FDI beyond brackish salinity.

Vortices-interaction-induced microstreaming for the pump-free separation of particles.

Microfluidic techniques have emerged as promising strategies for a wide variety of synthetic or biological sorting. Unfortunately, there is still a lack of sorting with automatic and handy operation. In contrast to passively generated vortices, the thermocapillary vortices produced by temperature gradient have the advantages of flexible manipulation, stable strength, and simple integration. In this Letter, we present a device used for the pump-free separation of particles through vortices interaction without external fluidic control systems required for the majority of existing devices. Specifically, the device induces a different flow type upon the actuation of optical power, and the flow functions, such as simultaneous pumping and sorting, agree with stimulation results very well. More importantly, our developed sorting device can achieve separations by means of tunable cutoff diameter size. Therefore, this versatile device can be utilized to sort complex samples with the advantages of portability, user-friendly control, and automation.

Design and Implementation of IoT based flood alert monitoring system using microcontroller 8051

In the Internet of Things (IoT) the physical objects network is described as “things” linked to sensors, software and other technologies to connect and share information through the Internet with other devices and systems. The floods lead to large losses of life and property in several countries. However, the absence of sufficient technology results in further death and property losses as a result of flooding in developed countries. This is because of a lack of flood alert systems. The objective of this paper is to monitor the flood situation and provide a text message warning in the event of a threat. The main aim of this paper is to detect rising river water levels at a safe distance away from the railways and to allow the respective authorities to take appropriate measures by means of SMS. A sensor is a system that senses and reacts to certain physical data. The 8051 microcontrollers were produced by Intel in 1981. The microcontroller is 8-bit. It has 40 DIP pins, 4 kb of ROM stores and 128 bytes of RAM and two timers and 16 bits. It is equipped with 2 timers. There are four parallel 8-bit ports that are programmable and adjustable as necessary. The hardware device that uses GSM mobile technology for the provision of an information link with a remote network is a GSM modem or a GSM module. A float switch is a level sensor type, a fluid control system that is used inside a tank. A condenser is a tool that stores electrical energy in an electric field. It's a passive electronic feature with two terminals. A LED is a semiconductor light source that transmits light through the flowing current. Liquid Crystal Display stands for LCD. It is a thin, flat display device used in a variety of electronics. A digital electronic level shifter is a system used in the transformation of signs from one logic or voltage domain to another, also known as logic level shifter or voltage level Translation. A diode is an electronic component with a two-terminal that mainly conducts current in one direction, with low resistance and high resistance in one direction. The aim of this paper is to detect early Flood and give early warnings to Needy people.

CONTROL APPROACHES FOR TEMPERING MACHINE TOOL FRAMES WITH MULTIPLE FLUID CHANNELS AND LIMITED, JOINTLY USED ACTUATING VARIABLE

Nowadays, the thermo-energetic design of a machine tool also includes the thermal stabilization of its machine components. In the past, thermal stability was irrefutable connected to minimizing the temperature gradient of machine tools by air conditioning the entire machine or even the factory hall. Today, thermal stability also defines minimal inhomogeneities in the temperature field of the machine tool due to higher energy efficiency requirements. Fluidic tempering systems of machine components offer considerable potential concerning the minimization of thermo-elastic displacements with acceptable energy demand. Hence, intelligent algorithms are required to combine tolerable geometric deviations with minimal energy effort. The scope of this paper is the integration of a demand-oriented fluidic temperature control system into a machine bed. The resulting multi-input-multi-output (MIMO) systems and varying boundary conditions are challenges, which are addressed. Therefore the paper compares two control approaches, a decentralized single-loop control and a multi-loop control by decoupling the control loops and especially focus on the distribution of the jointly used actuating variable, combined with the variation of different boundary conditions.

Effect of pH on Effective Slip Length and Surface Charge at Solid-Oil Interfaces of Roughness-Induced Surfaces.

Featured Application Drag reduction in many applications of micro-/nano-fluidic channel. In the development of micro/nano fluid control systems, fluid resistance has always been one of the key factors restricting its development. According to previous studies, it is found that the boundary slip effect of the solid-liquid interface can effectively reduce the resistance of the microfluid and improve the transport efficiency of the microfluid. The boundary slip length is mainly affected by surface wettability, roughness, and surface charge density. Among them, the influence mechanism of surface charge density on the boundary slip is the most complicated, and there is a lack of relevant research, and further investigation is needed. In this paper, we present research on quantification of effective slip length and surface charge density, where the roughness effect is considered. The electrostatic and hydrodynamic force data obtained from atomic force microscopy (AFM) measurements were fitted and processed for comparative analysis. We obtained the variation of surface charge density and effective slip length when different oleophobic surface samples were immersed in ethylene glycol with different pH values. The effect of pH on the surface charge density and effective slip length was investigated by their variations. The mechanism of the effect of pH on the surface charge density was discussed. The experimental results show that in the ethylene glycol solution, no matter whether the pH value of the solution increases or decreases, the charge density of the surface with the same properties decreases, and the effective boundary slip length also shows a downward trend. In deionized water, the surface charge density and effective boundary slip length decreases with the decrease of PH value.

Flow-Field-Assisted Dielectrophoretic Microchips for High-Efficiency Sheathless Particle/Cell Separation with Dual Mode.

Prefocusing of cell mixtures through sheath flow is a common technique used for continuous and high-efficiency dielectrophoretic (DEP) cell separation. However, it usually limits the separation flow velocity and requires a complex multichannel fluid control system that hinders the integration of a DEP separator with other microfluidic functionalities for comprehensive biomedical applications. Here, we propose and develop a high-efficiency, sheathless particle/cell separation method without prefocusing based on flow-field-assisted DEP by combining the effects of AC electric field (E-field) and flow field (F-field). A hollow lemon-shaped electrode array is designed to generate a long-range E-field gradient in the microchannel, which can effectively induce lateral displacements of particles/cells in a continuous flow. A series of arc-shaped protrusion structures is designed along the microchannel to form a F-field, which can effectively guide the particles/cells toward the targeted E-field region without prefocusing. By tuning the E-field, two distinct modes can be realized and switched in one single device, including the sheathless separation (ShLS) and the adjustable particle mixing ratio (AMR) modes. In the ShLS mode, we have achieved the continuous separation of breast cancer cells from erythrocytes with a recovery rate of 95.5% and the separation of polystyrene particles from yeast cells with a purity of 97.1% at flow velocities over 2.59 mm/s in a 2 cm channel under optimized conditions. The AMR mode provides a strategy for controlling the mixing ratio of different particles/cells as a well-defined pretreatment method for biomedical research studies. The proposed microchip is easy to use and displays high versatility for biological and medical applications.

(Invited) In Situ Observation of Anomalous Hydrogen Evolution on Mg Under Anodic Polarization

Mg alloys have long been considered a promising lightweight alloy system for various applications including consumer electronics, transportation, and medical equipment. However, owing to their high reactivity, Mg alloys cannot be used without proper coatings or surface treatments. Nevertheless, the chemical reactivity of Mg also opens up new ideas, such as the development of Mg-based biodegradable body implants and Mg metal battery systems. Unlike other metallic elements, Mg possesses a unique electrochemical response, especially under anodic polarization. To be specific, the rate of water reduction and hydrogen gas evolution, which is the dominant cathodic reaction on Mg in aqueous solutions, opposingly accelerates with the increase in anodic polarization. This phenomenon is the notorious negative difference effect (NDE) of Mg, or recently coined as the “anomalous hydrogen evolution”. Even after decades of research, the underlying mechanism of this peculiar electrochemical response of Mg is still under debate and yet to be elucidated.In order to have a clear picture of how the anomalous hydrogen evolution is related to the dissolution of Mg under anodic polarization, a customized cell was designed to enable high resolution in situ observation of the hydrogen evolution sites and surface morphology on Mg with an optical microscope. The compact cell is small enough to fit under the optical microscope with a short working distance at high magnification (50x-500x). The cell and the equipped reference and counter electrodes are connected to a potentiostat/galvanostat to control and monitor the polarization of the Mg working electrode. Additionally, a dynamic fluid control system is used to regulate the solution flow rate in the cell and constant circulation to avoid chemical or pH shifts. Additionally, the flowing solution also flushes away hydrogen bubbles attached to the electrode surface and ensure an unblocked view of the Mg surface. From this experimental setup, the anomalous hydrogen evolution under anodic polarization was found to be closely related to the actively propagating localized corrosion front of Mg. The relationship between hydrogen evolution response, applied anodic polarization, solution flow rate, as well as possible negative difference effect mechanisms, will be discussed. Figure 1

Development of a Droplet Microfluidics Device Based on Integrated Soft Magnets and Fluidic Capacitor for Passive Extraction and Redispersion of Functionalized Magnetic Particles

AbstractBased on a recent droplet microfluidic device for target molecules' extraction, purification, and redispersion, here an original fluidic control system is proposed to improve the device versatility and usability. This approach relies on the coupling of functionalized magnetic particles handling by integrated soft magnets and a passive droplet splitting control at a channel junction. To reach the high standards required for bioassays' implementation, this device integrates a pressure‐driven variable volume component, acting as a fluidic capacitor, which allows a passive and controlled self‐triggered droplet fingering in a dead‐end channel. The working principle is described, and the modeling of the induced fingering phenomenon by an electric analogy is presented. Then, the achieved finger length is characterized as a function of geometrical and material properties of the fluidic capacitor. The complete device configuration guarantees extraction and purification efficiencies higher than 97% and 95%, respectively, showing high‐throughput particles handling between droplets with a passive droplet splitting control. Finally, this technology is successfully applied to gene expression study for cancer diagnosis by performing magnetic particle–based messenger RNA (mRNA) extraction followed by reverse transcription (RT) and quantitative polymerase chain reaction (RT‐qPCR) analysis.

Vibration caused by swing check valve closure

Check valve or non-return valve is a commonly used component in fluid control systems, the function of the check valve is to allow the fluid to flow in one direction and prevent it from flowing backward in the opposite direction. There are many types of check valve that differs in structure, material, theory of operation, applications, installations constraints, etc. The swing check valve type has many advantages like lower pressure drop, high valve flow coefficient, ease of maintenance, etc. In this paper, the swing check valve type will be investigated using a new mathematical model that avoids the inaccuracy in explicit models and time consumption of evaluating different coefficients in implicit models. The present model is validated by comparing to experimental data. Investigation of the swing check valve is carried out in order to determine the vibration produced by its closing action and closing response. Also the effect of equipping the swing check valve with a torsion spring is investigated to figure out the spring effect on the valve induced vibration.

Применение специализированного программного обеспечения для разработки электронных устройств при проектировании пневматических приводов

A possible approach to overcoming the technological complexity of designing and manufacturing fluidics control units is shown. Information on the potential for expanding the possibility of applying fluid logic elements for industrial pneumatic controls components is presented. In particular, results from comparing the response speed and levels of power consumed by a fluidic control system and by similar systems on the basis of membrane-and-piston logic are given, from which a conclusion regarding the prospects of using fluid logic elements can be drawn. Information on a comparative service life of electromagnetic relays and membrane amplifiers is given. The article describes a method for using a simulator of general-purpose electronic systems with an open source code for designing and checking the operation of basic circuit diagrams of pneumatic control systems involving fluid logic elements. The LTSpice system was adopted as the simulator. The possibility of using fluid logic elements as an alternative to conventional contact-relay and membrane-and-piston devices is shown taking the pneumatic drive with two power cylinders as an example. The process of designing a logic control device based on fluid logic elements, including the construction of logic elements’ equivalent models and development of the complete circuit diagram is described. The construction of equivalent models is shown taking as an example a power cylinder and one of logic elements. Certain simplifications of the equivalent models in comparison with their physical prototypes are selected and substantiated. For comparison, the pneumatic drive schemes implemented using the conventional pneumatic devices and using the equivalent models of fluid logic elements are presented. The specific feature of plotting the cyclogram in the selected simulator is described. The fluidic equipment features limiting its application field in industrial pneumatic controls are considered, and the ways for coping with them are shown. Possible lines for further improvement of the computer-aided method for design of control systems and development of fluidics components from the point of view of their applications in industrial pneumatic drives are suggested.

Quest for Oxygen Dose Accuracy

Camcon’s fluid control system seeks to boost safety and cut costs

Problems in the fluid control system of the blood purification device (ACH-Σ)

Problems in the fluid control system of the blood purification device (ACH-Σ)

Abstract 5645: Critical variables to reduce Western blot variability

Abstract Reliable immunodetection of proteins is a critical step in the discovery of new biomarkers and diagnostic. 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 and reproducibility 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 source of errors during immunodetection. 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 new biomarker discovery and diagnostics, reliable protein quantification, primary antibody specificity testing, and optimization of primary and secondary antibodies concentrations. Citation Format: Russ Yukhananov, Alex Margulis. Critical variables to reduce Western blot variability [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5645.

Rapid detection of four mycotoxins in corn using a microfluidics and microarray-based immunoassay system

Mycotoxins threaten human health seriously because they usually exist in food, fodder and commodities. In this study, a rapid and sensitive immunoassay system for commonly encountered mycotoxins was established based on microfluidics and protein microarrays. Four mycotoxins (T-2 toxin, aflatoxin B1, ochratoxin A, and zearalenone) can be automatically detected in a custom-made microdevice within 30 min under the assistance of a prototype of the instrument with a fluid control system and an imaging system. Once the microdevices are fabricated, they are small-sized and user-friendly. Standard curves for each of the studied mycotoxins were generated with a good logistic correlation (R2 > 0.98). Working ranges from 0.1 to 20 ng/ml were employed in the immunoassay being the limit of detection achieved between 0.03 and 1.24 ng/ml. These values were calculated when the four mycotoxins were present in samples at the same time. Samples of spiked water and field corn were tested to assess the performance of our microfluidic-based detection technique for the mycotoxins. Recovery rates of mycotoxins from spiked water and corn samples were accessed and the results ranged from 80% to 110%, where the intra-assay coefficients of variation were under 15%. In summary, the system can realize rapid and reliable detection of multiple contaminants in actual samples automatically.

Automated Microfluidic Instrument for Label-Free and High-Throughput Cell Separation.

Microfluidic technologies for cell separation were reported frequently in recent years. However, a compact microfluidic instrument enabling thoroughly automated cell separation is still rarely reported until today due to the difficult hybrid between the macrosized fluidic control system and the microsized microfluidic device. In this work, we propose a novel and automated microfluidic instrument to realize size-based separation of cancer cells in a label-free and high-throughput manner. Briefly, the instrument is equipped with a fully integrated microfluidic device and a set of robust fluid-driven and control units, and the instrument functions of precise fluid infusion and high-throughput cell separation are guaranteed by a flow regulatory chip and two cell separation chips which are the key components of the microfluidic device. With optimized control programs, the instrument is successfully applied to automatically sort human breast adenocarcinoma cell line MCF-7 from 5 mL of diluted human blood with a high recovery ratio of ∼85% within a rapid processing time of ∼23 min. We envision that our microfluidic instrument will be potentially useful in many biomedical applications, especially cell separation, enrichment, and concentration for the purpose of cell culture and analysis.

Modified sliding mode design of passive viscous fluid control systems for nonlinear structures

A strategy is developed for design of passive control systems for structures experiencing inelastic deformations during earthquake loading. Besides the addition of passive energy dissipation devices, the proposed method suggests the required changes to the stiffness and strength of the structure, to reduce the absolute acceleration and relative deformation responses simultaneously. For this purpose, the locations and amounts of modifications in stiffness, strength and damping are determined by a sliding mode control algorithm to consider the nonlinear behavior of the structure. Being originally designed for active control, the sliding mode algorithm is modified to facilitate the extraction of the optimum properties of the passive control system from the active control design. By considering nonlinear structural response in design, the proposed technique provides a means for proper design of control systems to achieve the desired performance goals in major seismic events. Furthermore, by taking advantage of the freedom to simultaneously modify the structural stiffness, strength and damping properties, the proposed design method provides more versatility in the achievement of these performance goals. The effectiveness of this development is demonstrated through the analysis and design of control systems for an eight-story structure.

Solenoid Driven Pressure Valve System: Toward Versatile Fluidic Control in Paper Microfluidics.

As paper-based diagnostics has become predominantly driven by more advanced microfluidic technology, many of the research efforts are still focused on developing reliable and versatile fluidic control devices, apart from improving sensitivity and reproducibility. In this work, we introduce a novel and robust paper fluidic control system enabling versatile fluidic control. The system comprises a linear push-pull solenoid and an Arduino Uno microcontroller. The precisely controlled pressure exerted on the paper stops the flow. We first determined the stroke distance of the solenoid to obtain a constant pressure while examining the fluidic time delay as a function of the pressure. Results showed that strips of grade 1 chromatography paper had superior reproducibility in fluid transport. Next, we characterized the reproducibility of the fluidic velocity which depends on the type and grade of paper used. As such, we were able to control the flow velocity on the paper and also achieve a complete stop of flow with a pressure over 2.0 MPa. Notably, after the actuation of the pressure driven valve (PDV), the previously pressed area regained its original flow properties. This means that, even on a previously pressed area, multiple valve operations can be successfully conducted. To the best of our knowledge, this is the first demonstration of an active and repetitive valve operation in paper microfluidics. As a proof of concept, we have chosen to perform a multistep detection system in the form of an enzyme-linked immunosorbent assay with mouse IgG as the target analyte.

Fully-Deterministic Execution of IEC-61499 Models for Distributed Avionics Applications

The development of time-critical Distributed Avionics Applications (DAAs) pushes beyond the limit of existing modeling methodologies to design dependable systems. Aerospace and industrial automation entail high-integrity applications where execution time is essential for dependability. This tempts us to use modeling technologies from one domain in another. The challenge is to demonstrate that they can be effectively used across domains whilst assuring temporally dependable applications. This paper shows that an IEC61499-modeled DAA can satisfy temporal dependability requirements as to end-to-end flow latency when it is properly scheduled and realized in a fully deterministic avionics platform that entails Integrated Modular Avionics (IMA) computation along with Time-Triggered Protocol (TTP) communication. Outcomes from the execution design of an IEC61499-based DAA model for an IMA-TTP platform are used to check runtime correctness through DAA control stability. IEC 61499 is a modeling standard for industrial automation, and it is meant to facilitate distribution and reconfiguration of applications. The DAA case study is a Distributed Fluid Control System (DFCS) for the Airbus-A380 fuel system. Latency analysis results from timing metrics as well as closed-loop control simulation results are presented. Experimental outcomes suggest that an IEC61499-based DFCS model can achieve desired runtime latency for temporal dependability when executed in an IMA-TTP platform. Concluding remarks and future research direction are also discussed.

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.