This research is intended to create a prototype to generate controllable finger movement of a robotic prosthetic hand using Electromyography (EMG) signals. The instrumentation used in this project includes a Bitalino bio-signal sensor kit, skin electrodes, Arduino Uno microcontroller and a prosthetic hand. The Bitalino’s primary function is to serve as a means to obtain the EMG signal. The Arduino Uno’s function is to implement the control algorithm and actuate the robotic hand to move as intended. Using an EMG signal based counter, the method of control deemed fairly reliable since there was proportional control over the hand but it was based on the duration of the muscle in tension rather than how tense the muscle was. The overall control of the hand was generally responsive to the biological signal.

Enabling fast charging of Li-ion batteries (LiB) is essential for mainstream adoption of electric vehicles (EVs). A critical challenge to fast charging is lithium plating, which can lead to drastic capacity loss and safety risks. Fundamentally, fast charging is restricted by anode surface reaction kinetics, lithium diffusion in anode solid particles and Li + diffusion and conduction in electrolyte. In this work, we present an analysis of the contributions of these different physicochemical processes to the total overpotential during fast charging, using an electrochemical-thermal (ECT) coupled model. Special attention is paid to the effect of increasing electrode thickness, a common approach for raising energy density of EV cells, on fast charging capability. It is found that lithium plating is more prone to occur in thicker anodes due to larger electrolyte transport resistance. Furthermore, we present a novel approach of thermal stimulation to enable 10-minutes (6C rate) fast charging of an EV cell with 170Wh/kg energy density.

The present in vitro study aims at comparing the ablation volume obtained with commercially available RITA’s StarBurst ® XL (dry type) and StarBurst ® Xli-e (wet type) multi-tine electrodes during radiofrequency ablation (RFA) procedure. The experiments have been conducted on polyacrylamide based tissue-mimicking phantom gel whose thermo-electric properties are similar to that of the soft tissues. A temperature-controlled RFA has been performed utilizing AngioDynamics RITA 1500X ® radiofrequency generator. The maximal longitudinal and maximal transverse dimensions of the coagulated phantom gels have been measured from which the derived ablation volume has been calculated. Further, the temperature distribution and power delivered with the dry type and wet type electrodes have been compared. The in vitro study revealed that the efficacy of wet type electrode is more pronounced as compared to the dry type electrode. Moreover, it has been found that both the electrodes are capable enough of producing ablation volume up to 5 cm in diameter.

Dielectrophoresis (DEP) has been demonstrated as an effective mechanism for cell sorting in microfluidic settings. Many existing methods utilize sophisticated microfluidic designs that require complicated fabrication process and operations. In this paper, we present a microfluidics-based cell sorter that is capable of sorting microparticles continuously in a simple straight channel, thus facilitating easier fabrication and operation. An array of indium-tin oxide (ITO) electrodes are embedded on the bottom surface of the straight channel to generate a DEP force field. This force results in deviation of the particles with different dielectric properties from their paths that are hydrodynamically focused in the channel. Particle trajectories are predicted by numerical simulation at different flow rates and field strengths using COMSOL. Separation of red blood cells from polystyrene beads is demonstrated and numerical prediction is validated experimentally. High separation efficiency for the two particle types is confirmed by counting the concentrations of particles collected at the respective collection outlet.

In this study, the low-temperature energy efficiency of lithium-ion batteries (LIBs) with different chemistries and nominal capacities at various charge and discharge rates is studied through multi-physics modeling and computer simulation. The model is based on the irreversible heat generation in the battery, leading to the charge/discharge efficiency in LIBs with graphite/LiFePO 4 , graphite/LiMn 2 O 4 , and graphite/LiCoO 2 electrode materials in which the effects of the battery nominal capacity at various charge and discharge rates are studied. Using characterized sources of the heat generation in the LIB leads to providing a battery efficiency plot at different operation condition for each LIBs. The results of this study assist the battery engineers to have much more accurate prediction over the efficiency of the LIBs at low temperatures.

High voltage plasma-based technologies have the ability to impact multiple fields from medicine to engineering. The goal of the most recent study was to investigate the efficacy of a novel high voltage plasma system to generate oxygen (O 2 ) from carbon dioxide (CO 2 ) through dissociation. The general endothermic plasma-chemical process of CO 2 decomposition is presented, with CO 2 destruction accompanying production of oxygen (and carbon monoxide) at a mole ratio of 2 to 1. A high voltage plasma reactor was developed for this purpose. SEM analysis was conducted on electrodes used for plasma discharges, to better elucidate characteristics of the plasma. CO 2 gas samples were analyzed using an FTIR spectrometer. Baseline scans were taken of CO 2 inside the reactor before plasma power was turned on; subsequent scans were taken after 10 min of plasma treatment. Results of FTIR analysis presented here have indicated a 30% decrease in CO 2 concentration upon application of the developed plasma reactor. This paper reports on various aspects of the instrumented high voltage plasma reactor; and experimental results which further explore the capability to decrease CO 2 concentrations in various environments, while also generating O 2 .

Solid electrolyte interphase (SEI) film resistance is an important parameter in the study of charge transfer kinetics of a Li-ion battery. The passive film affects diffusion process of Li-ions. As such, it becomes essential to include film resistance in battery modelling. However, the traditional method of estimating the SEI film resistance is costly and time consuming. An indirect approach based on Ohm’s law is thus presented in this paper. It relies on determining the interfacial polarisation from the difference of open-circuit voltage measured immediately after switching off the applied current and the equilibrium voltage. The technique is simple, easy to implement and can be used for a quick estimation of SEI film resistance with reasonable accuracy. For instance, average value of SEI film resistance for commercial LFP battery cell is measured as 0.004 Ohm · m 2 , which was found to be consistent with the values determined using the impedance spectroscopy techhnique in the published literature for lithium-carbon film electrodes.

Health monitoring devices using a strain sensor, which shows high sensitivity and large deformability, are strongly demanded due to further aging of society with fewer children. Conventional strain sensors, such as metallic strain gauges and semiconductive strain sensors, however, aren’t applicable to health monitoring because of their low sensitivity and deformability. In this study, fundamental design of area-arrayed graphene nano-ribbon (GNR) strain senor was proposed in order to fabricate next-generation strain sensor. The sensor was consisted of two sections, which are stress concentration section and stress detecting section. This structure can take full advantage of GNR’s properties. Moreover, high quality GNR fabrication process, which is one of the important process in the sensor, was developed by applying CVD (Chemical Vapor Deposition) method. Top-down approach was applied to fabricate the GNR. At first, in order to synthesize a high-quality graphene sheet, acetylene-based LPCVD (low pressure chemical vapor deposition) using a closed Cu foil was employed. After that, graphene was transferred silicon substrate and the quality was evaluated. The high quality graphene was transferred on the soft PDMS substrate and metallic electrodes were fabricated by applying MEMS technology. Area-arrayed fine pin structure was fabricated by using hard PDMS as a stress-concentration section. Finally, both sections were integrated to form a highly sensitive and large deformable pressure sensor. The strain sensitivity of the GNR-base sensor was also evaluated.

Very little is known about the fracture behaviors of novel nanomaterials such as carbon nanotubes and graphene due to the difficulty of sample manipulation and in situ detection of their failure mechanism. In the present study, the design and analysis of a Microelectromechanical System (MEMs) device is presented for the tensile testing of single layer graphene. The electrostatically actuated dual parallel plate actuators in the proposed MEMS device enable in situ measurement in a scanning electron microscope by stretching the two ends of a nanostructured sample simultaneously. The elongation in the specimen is obtained by nonlinear finite element analysis using COMSOL, and MATLAB. For the validation of the proposed MEMS device, a lumped model of the system is utilized to analyze the stress-strain behavior of the nanostructured sample under the force generated by the electrodes.

The authors have proposed the formation of dumbbell-shape graphene nanoribbon (GNR) for developing various semi-conductive materials with metallic electrode at both ends. The novel dumbbell-shape structure, which has a center narrow part and wide parts to sandwich the narrow part, can be considered as a composite structure consisting of two single GNRs with different ribbon width. In this study, the electronic band structure of this dumbbell-shape GNR was analyzed by using the first principle calculation method. All the first-principles calculations were performed using DFT. Throughout these calculations, the electronic band structures, densities of states, and orbital distributions of the new dumbbell-shape structure GNR were examined to describe the electronic properties of dumbbell-shape GNRs and predict the performance of strain sensors. The band gap of dumbbell-shape GNRs is different to that of single GNRs. The magnitude of the band gap of the dumbbell-shape GNR depends on the combination of the single GNRs and the difference in the width of narrow part and wide parts. The main change to the band gap is attributed to a change in the orbital distributions of the lowest unoccupied molecular orbitals (LUMO) and the highest occupied molecular orbitals (HOMO). In addition, when a dumbbell-shape GNR undergoes a uniaxial tensile strain, its band gap showed high strain sensitivity as was expected. Therefore, the GNR material with a dumbbell-shape structure has great potential for use in highly sensitive strain sensors.

In this paper, we have introduced a negative Dielectrophoresis based microfluidic system using a novel arrangement of microelectrodes to perform switching of micro objects. Both the experimental and numerical results are presented. Two sets of interdigitated electrodes, extending slightly into the microchannel from each sidewall, are embedded on the bottom of the microchannel. A finite element model in COMSOL Multiphysics 5.2a was developed to demonstrate switching of Red Blood Cells in the microchannel followed by multiple parametric studies to study the effect of several parameters on cell trajectories and optimize the design parameters. To verify numerical results, a PDMS-based microfluidic device on glass wafer was fabricated. The switching of Red Blood Cells in the microfluidic device with a single inlet and three outlets was also demonstrated.

Nowadays, many surface sensing mechanisms exist, not all of them can be applied in water-based environment. Most of surface sensing techniques were developed in air-based environment. In order to obtain a potential cell-based biosensor, the sensing method needs to be reliable and repeatable in liquid environment. Therefore, we adapt existing air-based surface acoustic sensor and promote the technology into water-based applications. The goal of this study is to apply surface acoustic waves (SAW) for water-based environment sensing. We will use shear horizontal wave (SH wave) as surface sensing mechanism. SH wave is a type of surface acoustic waves (SAW) which can be used for weight/mass sensing in the air environment. Interdigitated transducers (IDTs) induce the deformation of an ST-cut quartz crystal substrate in AC source and generate waves. With a thin layer of polymer like Parylene and polyimide, the SH wave will be confined between the interface of substrate and polymer layer without suffering the energy loss due to the liquid damping from above. The fundamental frequency of the SAW device is defined by the spacing between the electrodes of IDT. The frequency of interests for this research is below 100 MHz in water-based environment. Due to the stable frequency characteristics of ST-cut quartz in room temperature, this SAW device can be a good candidate for field applications. From an early IDTs design, investigation in material and IDTs configuration is necessary to improve signal quality in order to qualify for liquid phase cell-based bio-sensing applications. A simplified 3D unit cell FEM model is created to study the thickness effects of wave-guide and electrodes. Boundary conditions and assumptions are discussed in the modeling. The simulated eigenfrequency of SH mode is close to the theoretical fundamental frequency of the 64μm wavelength IDTs. The mass damping effects from gold electrodes is more significant than aluminum electrodes.

The optical properties and device physics of monolayer graphene under light is investigated in this study. In order to understand the change of the electronic behavior of graphene under light, it was necessary to study from the most fundamental layer with high quality. Thus, it became mandatory to develop a highly efficient, low-cost fabrication process for synthesis of high-quality monolayer graphene. The high-quality monolayer graphene was grown on a copper foil using a low-pressure chemical vapor deposition (LP-CVD) method at temperature of 1035°C for 10 minutes. Acetylene was used as the precursor gas for the synthesis of monolayer graphene. Thin Pt/Au films were, then, deposited on a silicon dioxide/silicon (SiO 2 /Si) substrate using electron beam (EB) lithography which served as source and drain electrodes of a transistor. The synthesized graphene was, then, transferred to a SiO 2 /Si substrate using PMMA (polymethyl methacrylate)-assisted method. The quality of the synthesized graphene was validated using Raman spectroscopy. No significant D peak was observed in the Raman spectra of the synthesized graphene. This result validated the high quality of the transferred graphene. Next, the photo-sensitivity of G-FET was investigated under light source of color temperature of 2856 K at room temperature. The electron transfer characteristic of the fabricated G-FET was measured under dark and light illumination conditions. Finally, the graphene-based field effect transistor G-FET demonstrated an external photo responsivity of about 200 μA/W with a maximum photocurrent attained to be 0.2 μA at an incident luminance power of 1 mW. The active detection region of this sample was 1000 × 60 μm 2 .

The current research work in this paper involves optimizing an orthogonal electrode multifunctional system to transport biofluid. Orthogonal electrode patterned microfluidic device is known to produce high microflow velocity when excited by AC signals. This paper specifically investigates the fluid flow criterion by determining the direction and velocity in the selected electrode pattern actuated with AC signals. During the initial process, experiments were conducted at 100μm spacing between the orthogonal electrodes. The exact setup was placed on a hydrophobic surface to observe the change in the velocity. This process was then repeated with 150μm spacing. Fluid with conductivity 2.36 mS/cm was tested at voltage levels ranging between 5V to 10V at 50 KHz to 1MHZ frequency levels with an increment of 100 KHz. The goal of this research work is to increase microflow velocities by varying the electrode separation distance, flow surface, voltage and frequency. Trivial investigation also done on the possibility of micromixing using this pattern.

Corrosion fatigue growth behavior of structural steels at low cyclic frequency is characterized by an increase in crack growth rate in the threshold and Paris regions, due to the simultaneous action of cyclic mechanical load (fatigue) and corrosive environment. Knowledge on the effect of load sequence on corrosion fatigue crack growth is important to set out the realistic design and prognosis criteria for components operating under corrosive environments. In this study, the corrosion fatigue crack growth rate under the effect of hold-time (1000s), at a maximum stress intensity factor (K max ), interspersed during cyclic load on was studied experimentally on a Mn-Ni-Cr steel under 3.5% NaCl solution at a constant stress intensity factor range (ΔK) of 15 MPa √m; the corrosion crack growth rate was evaluated for three different frequencies of: 0.01, 0.1 and 1 Hz. As a result of hold time at the peak load, the exposure time for the crack-tip to interact with the environment increased, which could enhance the corrosion crack growth rates. To verify if this corrosion effect can be contained, electrode potential of (−) 850 mV and (−) 950 mV SCE was applied to the specimen to reduce the extent of corrosion contribution to crack growth rate. The fatigue crack growth rate (da/dN) increased when the frequency was decreased from 1 to 0.01 Hz at all electrode potentials. However, the crack growth rate at 0.01 Hz increased by an order of magnitude with a tensile hold at K max for 1000 s compared with the crack growth rate during continuous cyclic load for a given electrode potential. The crack growth rate reduced when the electrode potential was decreased to −950 mV SCE. The enhancement of corrosion fatigue crack growth rate with the introduction of a hold-time is explained using crack-tip strain rate assisted anodic dissolution.

Hybrid energy harvesting is a concept that can be applied to improve the performance of the conventional standalone energy harvesters. In this study, a hybrid energy harvesting device is presented that harvests energy from solar radiation and mechanical vibration by simultaneously combining the photovoltaic, piezoelectric, electrostatic, and electromagnetic mechanisms. The device consists of a bimorph piezoelectric cantilever beam having Lead Zirconate Titanate crystal layers on top and bottom surfaces of an Aluminum substrate. Two sets of comb electrodes (capacitors) are attached on two sides of the substrate. A permanent magnet is attached at the tip which oscillates within a stationary coil inside a casing. The exterior surface of the casing is covered by organic photovoltaic panel that captures energy from illumination. All the segments are interconnected by an electric circuit to generate combined output when subjected to solar radiation and mechanical vibration. Results for power output are obtained at the first resonance frequency of the beam with a common optimum load resistance. As the power outputs of all the mechanisms are combined, a high power efficiency can be achieved by the proposed hybrid energy harvester.

Metal Big Area Additive Manufacturing (mBAAM) is a promising approach to large-scale metal additive manufacturing (AM) or 3D printing. The mBAAM system uses an arc-based wire-fed welding robot to build metal parts. A multi-degree-of-freedom robotic arm is known for its extensive range of motion and reliable tool handling. Attaching a torch end-effector to a robotic arm gives it welding capabilities; however, this decreases the motion range and dynamics of the robot. As a result, build volume and printing accuracy are decreased. Additionally, only a portion of time is spent printing in an arc-based process. Maintenance leads to downtime on the system. In a tungsten inert gas (TIG)-based process, the torch electrode wears out over time and must be changed to avoid defective deposition. This paper proposes an approach for a compact torch end-effector to improve the robot’s build volume. This paper also proposes an approach to reducing non-printing process time by designing and implementing a semi-automated electrode changing system.

Previously published articles on detecting damage in electrically conductive panels mainly concentrate on electrical impedance tomography methods (EIT) which are based on using surface bounded boundary electrodes and taking advantage of an electrically conductive layer on the surface of the panel or of a conductive matrix material. In this study instead, embedded electrodes in glass fiber reinforced epoxy panels are used to locate and quantify the artificial damage inflicted on the panel. The panel was manufactured using vacuum infusion method. It consisted of 10 (S-2) glass fabric plies, where copper electrodes were embedded below the top layer and then vacuum infused with carbon nanotube (CNT) mixed epoxy. During all measurements, a constant electrical current was supplied from two outer electrodes (the source and sink) and changes in voltage from the two inner probes were recorded. In contrast to EIT methods, no complicated algorithm is used to solve the conductivity distribution of the panel but instead, a simple algorithm that fits Gaussian curves to the data obtained using a four-probe measurement technique. Using the fitted curves, we are able to detect location and magnitude of the damages within a confidence bound. This practical method reduces computational cost and also enables the use of embedded electrodes which could provide more durability for the sensors. The experimental data is in very good agreement with the finite element simulations. Comparison of relative voltage change before and after the damages is consistent and sensitive enough to detect damages down to 1/8” diameter hole inside an area of 33 in 2 . As expected, accuracy is higher for larger diameter holes.

Numerical and experimental studies performed to develop nanocomposites with varying carbon nanotube (CNT) alignment density within an epoxy matrix are presented. A 3-D numerical model has been developed that looks at the behavior of CNTs in epoxy resin subjected to non-uniform electric fields by explicitly accounting for electric field coupled with fluid flow and particle motion considering the transient resin viscosity. The transient nature of resin viscosity has been incorporated into the simulation study with data related to resin viscosity variation with time and temperature generated experimentally. The response of CNTs due to the induced dielectrophoretic force was studied using the numerical model. The model facilitated the design of an optimal electrode configuration for the processing of variable density composites. A computer controlled Arduino UNO based circuitry was developed to control supply of voltage to the electrodes during sample fabrication. The circuit was then integrated with AC voltage supply units and the electrode set-up for fabricating the variable density composite samples. Low weight fractions of CNTs (0.05 wt.% and 0.1 wt.%) in epoxy resin were used for the experimental work and preliminary experimental studies were conducted. Electrical characterization results of the variable density nanocomposites indicate over 100% and 30% increase in electrical resistance measured across sample widths in 0.05 wt.% and 0.1 wt.% CNT samples, respectively. The measured sample resistance values confirmed that variation in CNT alignment density was achieved across the samples.

This work investigates the effect of negative dielectrophoresis (DEP) on polystyrene particles inside an evaporating DI water droplet on a PDMS surface. Deposition patterns of actuated droplets transitioned from a scalloped rings to a striped deposition pattern as the particle diameter increased from 20 nm to 1 μm. Increased particle size dramatically increases the negative DEP force on particles that push them toward the lower field gradient expected in fluid between active electrodes. Interestingly, deposition patterns became more uniform when particle diameter was increased to 5 μm. This uniform pattern appears to be due to interfacial trapping as the diffusion rate of the large particles was significantly slower than the velocity of the descending interface. This work suggests that DEP can be used to control deposition patterns left by evaporating colloidal droplets, but further work examining the electric field gradient inside the droplet is required to determine if this technique can be applied to a wider range of particle sizes.