Dual Configuration Research Articles

Smart wearable flexible temperature sensor with compensation against bending and stretching effects

Flexible and stretchable temperature sensors have recently gained much attention due to their lightweight, thin profile, and ability to adapt to curved or irregular surfaces. Resistive temperature detectors (RTD) are one of the most commonly used sensors for temperature measurement. However, the major challenge with developing RTDs on flexible substrate is that the resistance not only changes with temperature, it also varies with mechanical deformation of the substrate, which can lead to significant errors in temperature measurement. In this paper we propose a novel flexible temperature sensor that can compensate for the deformation-induced resistance variation and measure temperature with minimum errors. The sensor is composed of two RTDs fabricated back-to-back on a polydimethylsiloxane (PDMS) substrate via stencil printing. The dual RTD configuration provides compensation against mechanical deformation caused by bending and stretching. When the sensor is bent on a curved surface, the resistances of the two RTDs change differentially due to tension on one RTD and compression on the other. As a result, the sum of resistance of both RTDs, RSum, remains a constant. Similarly, the subtraction of resistance of the two RTDs, RSub, can be used to compensate for the linear resistance change in sensor stretching. With the compensation methods in place, the sensor can be used for temperature measurement with enhanced accuracy. In addition, the sensor is connected to a Bluetooth-integrated microcontroller which is programmed to determine whether the sensor is undergoing bending or stretching. The compensation methodology can provide reliable measurement for a maximum radius of 40 mm when the sensor is bent or a maximum strain of 3% when it is stretched. The compensation method enhances the competence of flexible temperature sensors and increases their potential for applications in wearable electronics.

Optimal dual actuator loading configurations for extracting mixed-mode cohesive relations from interacting beams

Cohesive zone models are often used in analyses of interfacial fracture where the damage process zones are relatively large and can be described by proper traction-separation relations. Successful implementation of the cohesive zone modeling depends upon the veracity of the interfacial traction-separation relations used to represent the interactions across the interface. To extract the generally mixed-mode traction-separation relations experimentally, we compare various loading conditions for simultaneous extraction of the normal and shear interactions using laminated beam specimens subjected to asymmetric end loading. We develop a mixed-mode double cantilever beam model with linear normal and shear interactions between the contact surfaces of the beams. Four different loading conditions are considered by controlling the end forces, end displacements, end moments, or end rotations. The model is validated by finite element simulations. Rotation control is found to be the optimal loading configuration, based on a condition number that reflects desirable experimental characteristics for extracting the traction-separation relations. By applying uneven end rotations, the whole range of mode-mix with combined normal and shear interactions can be extracted, while ensuring stable crack growth.

Experimental study of a fully passive flapping hydrofoil turbine with a dual configuration and a coupling mechanism

The fully passive activation of a flapping hydrofoil turbine is an emerging scheme for increasing the power efficiency of these devices and simplifying the system complexity owing to the use of a pitching controller. In this study, a dual-flapping hydrofoil turbine (DFHT) of which the front hydrofoil oscillates upstream and the rear hydrofoil oscillates downstream with respect to the corresponding axis with a new coupling mechanism is suggested to realize fully passive activation. The pitch and arm angular motions of the front and rear hydrofoils are simply linked by chain connections so that the turbine can start independently. A mechanical spring is adopted in order to enhance the recovery force to the middle position. It is found from an experimental evaluation in a circulating water channel that the coupling mechanism activates the DFHT fully passively with a nearly 90-degree phase difference at the middle positions where the power peak exists. Subsequently, zero-power zones are removed from the total power curve. An increase in the spring constant increases the flapping frequency and the self-starting velocity of the DFHT. Eventually, fully passive activation could contribute to improving the power efficiency, and the 90-degree phase difference could be utilized to reduce power fluctuations.

Aerodynamic performance of a dual turbine concept characterized by a relatively close distance between rotors

AbstractIn this work, a closely spaced dual turbine concept is studied. The distance between the two side‐by‐side hubs is 1.05 , where is the rotor diameter. This configuration has a potential benefit for offshore wind developments in which power density can be maximized. The main goal is to evaluate the overall aerodynamic performance, blade loads, and wake structure of a reference wind turbine generator operating within this dual turbine configuration and to compare the effects against those for the typical single turbine configuration. For this purpose, an actuator line model has been employed together with the large eddy simulation approach for predicting the turbulence effects. This model was implemented by using the open‐source computational fluid dynamics toolbox OpenFOAM. Results show a better performance for the dual turbine concept. Under same operating conditions, the aerodynamic power of each turbine within the dual concept is higher than the power of the stand alone turbine, particularly at lower operating wind speeds (approximately 2% to 3% of extra power per turbine). Comparison between the two configurations shows similar character of the tangential and normal forces acting on the blades in terms of magnitude and fluctuation, eliminating potential concerns regarding fatigue and blade design. The largest difference in the tangential and normal root bending moments are approximately 3% and 2%, respectively, between single and dual turbine configurations. Finally, wake recovery analysis shows a downwind velocity deficit that is not enhanced streamwise in the dual turbine configuration with no considerable difference after 7 .

GAS turbine sensor fault diagnostic system in a real-time executable digital-twin

In this study, a sensor fault diagnostic system to detect/isolate and accommodate faults in sensors from an industrial gas turbine has been developed. The sensor fault diagnostic module is integrated with a gas turbine real-time executable digital-twin (RT xDT) reported in a previous study. The sensor fault diagnostic module of the digital-twin considers analytical sensor redundancy using a reference engine model to provide redundant estimates of measured engine variables. A Software-in-the-Loop (S-i-L) architecture and Hardware-in-the-Loop (H-i-L) facility are constructed to assess the sensor diagnostic module (fault detection/ fault isolation) during failure in sensors from the engine. The results demonstrated that if the discrepancy between virtual measurement (provided by digital-twin) and sensor measurement exceeds the prescribed tolerance levels, the sensor fault diagnostic logic determines the state of switching between the virtual and engine sensor measurements in a dual lane control configuration of the gas turbine control system. The sensor fault detection system implemented in the gas turbine RT xDT can be deployed onto a distributed control system of industrial gas turbines to diagnose sensor deficiencies and ensure continuous and safe operation of the gas turbine. Consequently, the developed system will increase engine availability and reliability by diagnosing engine operational deficiencies before severe failure.

History and Future Directions of rTMS for Treatment of Depressive Disorders

History and Future Directions of rTMS for Treatment of Depressive Disorders

In Vivo Plant Bio-Electrochemical Sensor Using Redox Cycling.

This work presents an in vivo stem-mounted sensor for Nicotiana tabacum plants and an in situ cell suspension sensor for Solanum lycopersicum cells. Stem-mounted sensors are mechanically stable and less sensitive to plant and air movements than the previously demonstrated leaf-mounted sensors. Interdigitated-electrode-arrays with a dual working electrode configuration were used with an auxiliary electrode and an Ag/AgCl quasi-reference electrode. Signal amplification by redox cycling is demonstrated for a plant-based sensor responding to enzyme expression induced by different cues in the plants. Functional biosensing is demonstrated, first for constitutive enzyme expression and later, for heat-shock-induced enzyme expression in plants. In the cell suspension with redox cycling, positive detection of the enzyme β-glucuronidase (GUS) was observed within a few minutes after applying the substrate (pNPG, 4-Nitrophenyl β-D-glucopyranoside), following redox reactions of the product (p-nitrophenol (pNP)). It is assumed that the initial reaction is the irreversible reduction of pNP to p-hydroxylaminophenol. Next, it can be either oxidized to p-nitrosophenol or dehydrated and oxidized to aminophenol. Both last reactions are reversible and can be used for redox cycling. The dual-electrode redox-cycling electrochemical signal was an order of magnitude larger than that of conventional single-working electrode transducers. A simple model for the gain is presented, predicting that an even larger gain is possible for sub-micron electrodes. In summary, this work demonstrates, for the first time, a redox cycling-based in vivo plant sensor, where diffusion-based amplification occurs inside a tobacco plant's tissue. The technique can be applied to other plants as well as to medical and environmental monitoring systems.

Numerical analysis and performance assessment of trapezoidal oscillating water columns

ABSTRACT Oscillating water column (OWC) device serve as a wave energy conversion tool in the on-shore and off-shore environment. This study encompasses the literature on OWC with single and multi-chambers for efficiency improvement. Geometrical configurations are modified from rectangular to trapezoidal in order to understand the fluid dynamics inside the OWC. The pressure drop and wave elevations are carefully matched and validated first and error limits are analysed. Further studies continue with the air pressure rise and fall inside the OWC and therefore the power-take off for the wave configurations is calculated. The dual OWC configuration separated by a wavelength distance offers the highest capture width ratio at all wave height and time periods. From the results, the capture width ratio is significant with the trapezoidal tandem configuration which is 9.96% increase with respect to a single-OWC configuration. A marginal increase of 2.87% is observed in trapezoidal case against rectangular shape in the context of tandem configuration.

Fluid-Structure Interactions and Aeroacoustic coupling of Airfoil with Flexible Membrane(s)

In this paper, fluid-structure interactions of a NACA 0012 airfoil mounted with short flexible membrane(s) and its coupling effect on airfoil aeroacoustics are presented. A time-domain direct aeroacoustic simulation coupled with structural dynamics is carried out at a low Reynolds number of 50,000 to explore the aeroacoustic-structural interactions. Two different airfoil configurations based on single and dual membranes are analyzed. The membrane deflections and their impact on the flow field are characterized in wavenumber-frequency domain to analyze the structural dynamics due to flow unsteadiness within the laminar boundary layer and the resulting acoustic waves emanating from the airfoil trailing edge. A strong correlation between the membrane displacement and downstream propagating flow is observed for all configurations whereas the correlation is considerably weakened between the membrane displacement and upstream acoustic waves which ultimately results in the airfoil self-noise reduction without affecting the airfoil aerodynamics. The extent of noise reduction for dual membrane airfoil configuration is observed to be considerably higher than the single membrane airfoil configuration which corresponds to a much lower correlation among the upstream propagating acoustic waves and membrane deflection for both the membranes and redistribution of upstream flow energy into different frequencies.

Mire and Pelage-Mucoepidermoid Carcinoma Salivary Gland

Mucoepidermoid carcinoma of salivary gland is a frequently encountered, malignant neoplasm arising from salivary gland epithelium constituted of mucous cells, intermediate cells and epidermoid cells. Tumefaction is associated with specific chromosomal translocation t(11;19)(q14-21;p12-13) and CRTC1(MECT1)-MAML2 genetic fusion. Median age of disease emergence is 49 years and a mild female preponderance is observed. Neoplasm predominantly incriminates major salivary glands as the parotid gland. Tumefaction depicts a solid, cystic or dual configuration and is composed of neoplastic epidermoid cells demonstrating solid nests, sheets or cellular cords along with varying proportion of epidermoid cells, intermediate cells or mucocytes. Tumour cells appear immune reactive to pan-cytokeratin, CK5/6, p63, p40, epithelial membrane antigen(EMA), CK7 or CK14. Membrane bound mucins appear immune reactive to MUC1, MUC2, MUC4, MUC5AC and MUC5B. Mucoepidermoid carcinoma requires segregation from neoplasms such as pleomorphic adenoma with squamous cell and mucinous cell metaplasia, necrotizing sialometaplasia, Warthin tumour with squamous metaplasia, acinic cell carcinoma, mammary analogue secretory carcinoma (MASC), primary or secondary squamous cell carcinoma or salivary duct carcinoma. Preoperative assessment with ultrasonography or fine needle aspiration cytology may be beneficially employed. Tumefaction may be subjected to comprehensive surgical eradication with excision of broad perimeter of uninvolved, circumscribing soft tissue.

A rapid and green GC-MS method for the sampling of volatile organic compounds in spices and flowers by concurrent headspace single-drop microextraction and solid-phase microextraction.

The equilibrium rather than the exhaustive nature of headspace single-drop microextraction (HS-SDME) and headspace solid-phase microextraction (HS-SPME) allowed the concurrent sampling of volatile organic compounds (VOCs) on the same sample in the same vial in a dual extraction configuration. This has avoided the necessity of conducting a separate set of experiments and was found to produce results in the time duration of a single sample preparation experiment. The results obtained by HS-SDME were validated against those found by the standard method of HS-SPME. Rectilinear calibration was made for certain VOCs tested as analytes over the range of 0.01-8 μg g-1, and the average values of R2, LOD and LOQ were found to be, respectively, 0.9992, 1.9 ng g-1 and 5.7 ng g-1 in HS-SDME, and 0.9991, 3.1 ng g-1 and 9.1 ng g-1 in HS-SPME. The spiked recoveries and RSD were, respectively, 100.5% and 3.3% in HS-SDME and 98.1% and 3.6% in HS-SPME. HS-SDME is convenient to perform and produce results in a much cheaper way than HS-SPME and free from the inconveniences of memory effects. With GC-MS, this method has also been implemented as a rapid, reliable and green procedure (by GAPI and AGREE tools) for the sampling of VOCs in real samples of spices, flowers, and a beetle nut chewing sample illicitly containing tobacco.

Generating a beneficial creative chaos to manage compartmentalization in psychology: A trans-disciplinary approach to intertwine plurality and unity

The search for a composition between plurality and unity of psychology is developed here by articulating a reflection on three points concerning: the origins of the phenomenon of compartmentalization that can be traced back to a dual configuration - plural and fragmented - of psychology; characteristics that are connected but not coincidental; the acceptability of a trans-disciplinary approach to design a composition of psychology that respects its plural articulation; the choice of the area of health as the elective phenomenical field to test the possibility of composing the plurality and unity of psychology starting from a trans-disciplinary approach.

A Novel Wearable Upper-Limb Rehabilitation Assistance Exoskeleton System Driven by Fluidic Muscle Actuators

This paper proposed a novel design using a torsion spring mechanism with a single fluidic muscle actuator (FMA) to drive a joint with one degree-of-freedom (DOF) through a steel wire and a proportional pressure regulating valve (PRV). We developed a 4-DOF wearable upper-limb rehabilitation assistance exoskeleton system (WURAES) that is suitable for assisting in the rehabilitation of patients with upper-limb injuries. This system is safe, has a simple mechanism, and exhibits upper-limb motion compliance. The developed WURAES enables patients with upper-limb musculoskeletal injuries and neurological disorders to engage in rehabilitation exercises. Controlling the joint is difficult because of the time-varying hysteresis properties of the FMA and the nonlinear motion between standard extension and flexion. To solve this problem, a proxy-based output feedback sliding mode control (POFSC) was developed to provide appropriate rehabilitation assistance power for the upper-limb exoskeleton and to maintain smooth and safe contact between the WURAES and the patient. The POFSC enables the overdamped dynamic of the WURAES to recover motion to be aligned with the target trajectory without a significant error overshoot caused by actuator saturation. The experimental results indicate that the proposed POFSC can control the designed WURAES effectively. The POFSC can monitor the exoskeleton system’s total disturbance and unknown state online and adapt to the exterior environment to enhance the control capability of the designed system. The results indicate that a single FMA with a torsion spring module exhibits a control response similar to a dual FMA configuration.

CONFIGURATIONS OF HIGHER ORDERS

This paper begins by extending the notion of a combinatorial configuration of points and lines to a combinatorial configuration of points and planes that we refer to as configurations of order $2$. We then proceed to investigate a further extension to the notion of points and $k$-planes ($k$-dimensional hyperplanes) which we refer to as configurations of order $k$. We present a number of general examples such as stacked configurations of order $k$ - intuitively layering lower order configurations - and product configurations of order $k$. We discuss many analogues of standard configurations such as dual configurations, isomorphisms, graphical representations, and when a configuration is geometric. We focus mostly on configurations of order $2$ and specifically compute the number of possible symmetric configurations of order $2$ when each plane contains $3$ points for small values on $n$ - the total number of points in the configuration.

Minimum DC Voltage Ripple Switching Sequence Elicitation for Dual Inverter Through AC Load Error Volt-Sec Computation

In voltage source inverters (VSI), the output voltage is synthesized in an average sense using pulsewidth modulation (PWM) techniques. In space vector PWM techniques, the average realization of the space vector using volt-sec balance results in an instantaneous error that influences the dc bus current. The instantaneous ac load error voltage maps onto the dc bus derive the dc bus current ripple signatures that would be useful to size the dc capacitor. Exploiting concept of instantaneous mapping of ac error voltage onto the dc bus through power factor axis coordinates, in this work, the unprecedented dc ripple voltage computational method is presented. The established synchronous power factor reference frame ensures accurate mapping of ac error voltage onto the dc bus and makes the computational method independent of sensing actual ac load current unlike conventional methods. With the eliminated actual load current dependence, the proposed model can predict the minimum dc voltage ripple yield switching sequence for VSIs at different loading conditions. The efficacy of the proposed model in terms of optimum switching sequence elicitation is demonstrated on the dual inverter configuration experimentally considering the inflated switching stress due to two inverter's switching.

Energy Performance of Annual Operation of Heat Pump Coupled with Ground Ice Storage and Photovoltaic/Thermal modules

The use of heat pumps for annual climatization is a suitable mean of achieving the 2030 European decarbonization target (-55% with respect to 1990 CO2 emissions). The use of seasonal energy storages allows to store one of the two contemporaneous effects (thermal and cooling energy) produced by the heat pump to be used successively when it is necessary. This paper focuses on a dynamic simulation to size the heating and cooling plant and define a suitable control logic for a refurbished building located in northern Italy. The plant is set up by an electric heat pump in annual operation, coupled with a ground ice storage. Ice produced during heating operation is used in summer to face cooling loads (free cooling). PhotoVoltaic/Thermal modules allow to increase the grid independency and to reduce primary energy consumption of the plant as they can be suitably cooled in any season, by recovering heat for domestic hot water or the ground. A dynamic simulation of the system allows for a full description of the behaviour of the ice tank during the charging and discharging processes. In addition, a primary energy performance analysis of the whole plant is reported, also in comparison to a dual source heat pump configuration for the same building.

Ion-Exchange Reaction-Mediated Hierarchical Dual Z-Scheme Heterojunction for Split-Type Photoelectrochemical Immunoassays.

Photoelectrochemical (PEC) immunoassays with ultrasensitive detection abilities are highly desirable for in vitro PEC diagnosis and biological detection. In this paper, dual Z-scheme PEC immunoassays with hierarchical nanostructures (TiO2@NH2-MIL-125@CdS) are synthesized through epitaxial growth of MOF-on-MOF and further in situ derivatization. The dual Z-scheme configuration not only extends the light absorption range but also increases the redox ability due to the interface structure nanoengineering, which synergistically suppresses bulk carrier recombination and promotes the charge transfer efficiency at the electron level. Furthermore, a smart MOF-derived labeling probe (CuO@ZnO nanocube) is designed to develop a split-type PEC biosensor by using prostate-specific antigen (PSA) as a target biomarker. In the presence of PSA, the Ab2-labeled CuO@ZnO would specifically bond to the dual Z-scheme electrode. Then, the MOF-derived CuO@ZnO is dissolved by hydrochloric acid to release Cu2+, which could replace Cd2+ via an ion-exchange reaction, thus leading to the decrease of the photocurrent due to the destruction of the dual Z-scheme configuration. In typical applications, the split-type PEC immunoassay exhibits an excellent detection performance for PSA with a LOD as low as 0.025 pg·mL-1.

The influence of support arms on the performance of vertical axis wind turbines

The vertical axis wind turbines (VAWT) are being used for small to medium-scale energy extraction, primarily for off grid applications. Several investigations on the VAWTs dealing with turbine blade optimisation and applications are reported. However, most of the literature have often neglected the effect of turbine arms during the numerical analysis, except a few. This study concerns the aerodynamic characteristics of support arm in 3D numerical predictions on the performance of a two-bladed VAWT with dual support arm configuration. Results with arms were compared against an ideal turbine with no support arms, which was set as the baseline. The numerical study with respect to power coefficients as well as characterisation of the turbine flow physics during turbine operations were conducted. The difference increased as the TSR value increased. The power coefficient comparisons saw a significant reduction in the predicted power coefficient due to the parasitic effect of the turbine arms. Both velocity and pressure contours showed that the turbine support arms' added consideration results in a much more turbulent flow around the turbine.

Dual color, frequency, pulse duration and shape agile laser system for particle spectroscopy and manipulation.

A dual color, frequency and pulse duration agile laser system, capable of delivering laser pulses in arbitrary temporal profiles with ∼1 ns to ∼1 µs pulse duration, chirping rates of ∼27 MHz/ns with an achievable chirping range of several GHz across the pulse duration, and with energies ranging from a few nJ to hundreds of mJ per pulse has been developed. The flexibility and capability of this laser system provide a wide range of laser parameters that can be exploited to optimize operational conditions in various experiments ranging from laser diagnostics to spectroscopy and optical manipulation of matter. The developed system is successfully demonstrated to obtain coherent Rayleigh-Brillouin scattering (CRBS) in both single and dual color configuration, in an effort to expand the non-intrusive accessibility towards lower pressure regime for neutral gas and plasma diagnostics.

Large Eddy Simulation Investigation of Low Rossby Number Buoyant Flow in Rotating Cavities

Abstract Flow and heat transfer in axial compressor disk cavities involve strong interaction of axial throughflow at the disk bores with centrifugal buoyant flow in the cavities. This paper presents large eddy simulation (LES) of flow and heat transfer in rotating cavities with a heated shroud and a relatively weak axial cooling throughflow. The conditions considered for a single cavity configuration correspond to Rossby numbers Ro=0.2 and 0.3, rotational Reynolds numbers ReΩ=3.2× 105 and 7.7×105, and buoyancy parameters βΔT=0.24 and 0.26. Reasonable agreement of the results with shroud heat transfer measurements was confirmed for the Ro=0.2 condition for which test data were available. A dual cavity configuration for Ro=0.3 and ReΩ=3.2× 105 is also modeled. The simulations show that, at low Ro conditions, flow reversals occur along the length of the bore flow path, upstream and downstream of the rotating cavities. With the dual cavity strong, unsteady interactions between the flows in the two cavities occur. These flow interactions result in less stable flow structures, higher air temperatures within the cavities and lower shroud and disk heat transfer compared to the single cavity case. FFT analysis reveals a complex phase-locking mechanism between flows in the two cavities.