This work presents the development and application of a 3D printed non-contact microfluidic probe for delivering DNA vaccines into mammalian cells, with a single cell resolution (40 micrometer diameter). The platform constitutes of a 3D printed micro-electro-fluidic probe (MeFP) and a conductive cell culture substrate. It operates by simultaneously creating temporary pores on the cell membrane with an electric pulse and isolating the DNA molecules to a target area. Using the developed tool, we show successful transfer of propidium iodide (PI), a membrane impermeable molecule, through the membranes of single HeLa cells. Our results demonstrate the MeFP as the first microfluidic based electroporation technology that is reconfigurable for single or multiple cell targets. These results demonstrate the MeFP as an affordable technology that can also be used for gene therapy, in vitro fertilization, cancer treatment, regenerative medicine, and induced pluripotent stem (iPS) cells.
The development of efficient and deactivation-resistant catalysts is required to produce a high yield of diesel, kerosene and jet fuels. The development of zeolites as catalysts in hydrocracking caused a major breakthrough due to their superior activity, stability, and gasoline selectivity as compared to amorphous silica-alumina catalysts. Y-type zeolites having uniform crystal pore sizes, and strong Br?nsted acidity arising from the bridging OH groups, are largely used as catalysts in industrial processes such as, hydrocracking, isomerization, and alkylation. Zeolite Y has been progressively enhanced to improve its activity and selectivity towards the products of interest in hydrocracking processes. In addition, hydrogenation-dehydrogenation processes are promoted by impregnated metal particles such as, nickel, molybdenum, and tungsten. In this study, two approaches have been adopted to prepare/modify zeolite Y for catalyzing hydrocracking reactions: (i) ball milling and (ii) in-situ growth of metals on the zeolite.
In the present study, enhanced microwave (EMW) synthesis, where microwave radiation is coupled with reflux conditions, was used to prepare binary Ce-M-O (M= La, Sm) and ternary Ce-M-Cu-O (M= La, Sm) catalysts. It is well known that ceria-based oxides feature high redox properties including high population of oxygen vacancies [Ovac]. These properties are crucial for hydrocarbon catalytic reactions such as CO2 reforming of methane (dry reforming of biogas), in the sense that they contribute to coke reduction. Post synthetically, the catalysts, were calcined at 500?C followed by ball milling in selected composition cases. The ball milling technique is expected to give higher efficiency for uniform multi-component mixed oxides in consideration of time and energy usage. The prepared catalysts were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Remarkably, the EMW synthesis conditions affect the crystallinity of the catalysts (XRD), and crystal growth, generating particles with crystallite size in the nano-metric ranges. The catalysts present a flake-like shape and random agglomerates morphology (SEM). The ball-milled catalysts exhibited a very small crystallite size (XRD), which corresponds to larger surface area (m2/g). This, in fact, enhances oxygen mobility in ceria support lattice and yield to the formation of more O vacancies.
The autoclave curing process of composite structures leads to Process-induced Deformations (PIDs) in which the composite structures deform, and their dimensions deviate from the design drawings. PIDs can hinder the assembly process and potentially lead to scraping the part. PIDs within the assembly tolerance can be achieved either by adjusting the tool or modifying the design and process parameters. Predicting PIDs, experimentally, costs raw material and manhours, whereas simulation tools allow predicting PIDs, testing and introducing modifications to the design and the manufacturing process with less risk and cost. Many research papers discussed the PIDs of laminated structures, but few addressed the sandwich structure. This paper discusses predicting the spring-in of a U-shaped sandwich structure using ABAQUS/COMPRO simulation tools. PID was predicted with error of less than 5% and the effect of core material on PIDs was discussed. This indicates that simulation can predict PIDs of aero-structures with high accuracy.
Composite material applications in the aerostructure manufacturing industry are rapidly increasing. These aerostructures can be monolithic, e.g., A350 Inboard Flaps, or sandwich structures, e.g., A330 spoilers. Curing composite structures in the autoclave generates residual stresses that lead to dimensional infidelity known as Process-induced Deformations (PIDs) due to stress relaxation after structure demoulding. These stresses arise in composite structures mainly due to the anisotropy nature of the composite material, and the tool-part interaction. PIDs are a concern in the assembly stage of the final composite structure when they are not accounted for in the design phase. They can be predicted experimentally or by simulation using ABAQUS/ COMPRO simulation tools. This paper discusses PIDs simulation results using validated FE models for two commonly used composite structures in the aerospace industry; monolithic and sandwich structures. PID was predicted with high accuracy (Error < 20%), and the residual stresses were discussed as well.
This paper presents analog circuit for signal processing of biosignals using wavelet transform. The proposed 7th-order OTA-C band pass filter provides programmable gain ranging from -7.65 dB to 23.2 dB, and tunable center frequency from 0.162 Hz to 101 Hz. The filter topology is based on an OTA-C structure providing a Balanced-Input Balanced-Output (BIBO) filter realization with grounded capacitors. The filter is simulated in LTspice using 90 nm CMOS technology providing a dynamic range of 55.9 dB and low power consumption of 1.02 nW.
This work explores the effects of linear proportional integral and nonlinear fractionalorder (FO) proportional integral (PI) control strategies on an electric vehicle traction system. A 400 V, 6.6 Ah Li-ion battery bank is established to power an indirect field-oriented controlled prototype electric vehicle drivetrain. In contrast to integer-order (IO) PI controllers, the nonlinear nature of fractional-order PI controller provides immunity to induction motor parameters variation and external disturbances. The appeal of this paper is to reveal the simplicity, robustness, and effectiveness of fractional-order PI speed regulator for electric vehicle traction system. The efficacy of FO-PI speed regulator for the electric vehicle applications is validated through experimentation.
In this work, universal adaptive stabilizer (UAS) based particle swarm optimization strategy is developed for accurate identification of Li-ion battery model parameters. Among various battery parameters estimation techniques, UAS based adaptive parameters estimation (APE) strategies have an advantage of estimating battery model parameters within few computational cycles and are proven to provide estimated battery parameter convergence with reasonable accuracy. However, embedding optimization routine after UAS based adaption process can help to increase the accuracy of battery parameters. The UAS based APE strategy assists in narrowing search space for the optimization method following the adaptive estimation and, thus, renders the optimization process highly efficient in terms of computational time required to produce accurate results. The simulation results are validated against a well-known experimentally validated Li-ion battery model.
Bromate is carcinogenic substance introduced into drinking water in the process of ozonolysis. Various forms of activated carbon have been used for its removal, while other classes of materials have been neglected as viable sorbents. Herein, we synthesized a cationic porphyrinbased covalent organic framework (COF) through the Zincke reaction. The COF exhibited the morphology of uniform spheres, which were used as-synthesized, post-synthetically metallated with Zn, or had their cationic viologen subunits fully reduced to neutral. The three COFs were tested for bromate removal at an industrially relevant concentration of 50 ?g/L. The as-synthesized COF performed best, removing over 95 % at a rate of 191.45 g/mg/min, which is one of the fastest rates of adsorption reported till date, and bringing bromate concentration down to well below the permitted drinking water concentration of 10 ppb. The same COF reached a maximum uptake capacity of 203.8 mg/g, one of the highest values reported.
This paper proposes adaptive tuning of PI gains using modified high-gain adaptive controller to overcome fixed PI gains performance degradation in the presence of external disturbances and motor parameters variation. This adaptive gain tuning mechanism depends on the speed tracking error signal. High-gain adaptation of PI gains, although stable in many applications, is unstable for induction motor. This instability is caused by the ever-increasing PI gains and is the result of the persistent error sources such as encoder readings. Therefore, different modifications on high-gain such as sigma, dead zone, and epsilon modifications are proposed to overcome the instability of the high-gain PI tuning. The performance of high-gain adaptive PI controller with these modifications is experimentally investigated on an Indirect Field Oriented (IFO) induction motor drive system. It is shown that dead zone and epsilon modified high-gain adaptive PI controllers outperform the fixed gains PI controller when evaluated based on speed profile and torque commanded current.
