MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS

Design, development and performance analysis of FSPV system for powering sustainable energy based mini micro-grid
Bhattacharya S, Goswami A and Sadhu PK
The Floating Solar Photovoltaic System (FSPV) is emerging as a favorable technology to policymakers for economically harvesting renewable energy. The implementation of large-scale photovoltaic (PV) systems is often disrupted due to the unavailability of land. The FSPV systems, where the PV modules are floated in water bodies facilitate optimal utilization of water resources and land assets. The FSPV provides higher power output compared to land-based PV systems of the equal area because of improved energy conversion efficiency at a lower temperature. Another opportunity for the FSPV system is integration with hydropower stations, storage systems, and the electric grid. This paper explores the flood duration curve-based optimal sizing of the FSPV System with the objective of electrification of rural micro-grid. A comparison of energy output and module temperature rise has been made for the FSPV system and its equivalent land-based PV system of equal area. The system generates 18.08 GWh, which is 10.04% more than the land-based PV system. The DC Capacity factor is 17.2%. The Demand Supply Factor () for a particular day in winter, spring, summer, and monsoon is 37.55%, 41.7%, 45.9%, and 25% respectively. The results indicate that the FSPV system is a sustainable alternative to power renewable energy-based mini micro-grid and provide cost effective electricity to all.
Arrays of High-Aspect Ratio Microchannels for High-Throughput Isolation of Circulating Tumor Cells (CTCs)
Hupert ML, Jackson JM, Wang H, Witek MA, Kamande J, Milowsky MI, Whang YE and Soper SA
Microsystem-based technologies are providing new opportunities in the area of in vitro diagnostics due to their ability to provide process automation enabling point-of-care operation. As an example, microsystems used for the isolation and analysis of circulating tumor cells (CTCs) from complex, heterogeneous samples in an automated fashion with improved recoveries and selectivity are providing new opportunities for this important biomarker. Unfortunately, many of the existing microfluidic systems lack the throughput capabilities and/or are too expensive to manufacture to warrant their widespread use in clinical testing scenarios. Here, we describe a disposable, all-polymer, microfluidic system for the high-throughput (HT) isolation of CTCs directly from whole blood inputs. The device employs an array of high aspect ratio (HAR), parallel, sinusoidal microchannels (25 µm × 150 µm; W × D; AR = 6.0) with walls covalently decorated with anti-EpCAM antibodies to provide affinity-based isolation of CTCs. Channel width, which is similar to an average CTC diameter (12-25 µm), plays a critical role in maximizing the probability of cell/wall interactions and allows for achieving high CTC recovery. The extended channel depth allows for increased throughput at the optimized flow velocity (2 mm/s in a microchannel); maximizes cell recovery, and prevents clogging of the microfluidic channels during blood processing. Fluidic addressing of the microchannel array with a minimal device footprint is provided by large cross-sectional area feed and exit channels poised orthogonal to the network of the sinusoidal capillary channels (so-called Z-geometry). Computational modeling was used to confirm uniform addressing of the channels in the isolation bed. Devices with various numbers of parallel microchannels ranging from 50 to 320 have been successfully constructed. Cyclic olefin copolymer (COC) was chosen as the substrate material due to its superior properties during UV-activation of the HAR microchannels surfaces prior to antibody attachment. Operation of the HT-CTC device has been validated by isolation of CTCs directly from blood secured from patients with metastatic prostate cancer. High CTC sample purities (low number of contaminating white blood cells, WBCs) allowed for direct lysis and molecular profiling of isolated CTCs.
A novel microneedle array for the treatment of hydrocephalus
Oh J, Liu K, Medina T, Kralick F and Noh HM
We present a microfabricated 10 by 10 array of microneedles for the treatment of a neurological disease called communicating hydrocephalus. Together with the previously reported microvalve array, the current implantable microneedle array completes the microfabricated arachnoid granulations (MAGs) that mimic the function of normal arachnoid granulations (AGs). The microneedle array was designed to enable the fixation of the MAGs through dura mater membrane in the brain and thus provide a conduit for the flow of cerebrospinal fluid (CSF). Cone-shaped microneedles with hollow channels were fabricated using a series of microfabrication techniques: SU-8 photolithography for tapered geometry, reactive ion etching for sharpening the microneedles, 248 nm deep UV excimer laser machining for creating through-hole inside the microneedles, and metal sputtering for improved rigidity. Puncture tests were conducted using porcine dura mater and the results showed that the fabricated microneedle array is strong enough to pierce the dura mater. The biocompatibility test result showed that none of the 100 outlets of the microneedles exposed to the bloodstream were clogged significantly by blood cells. We believe that these test results demonstrate the potential use of the microneedle array as a new treatment of hydrocephalus.
A microacoustic analysis including viscosity and thermal conductivity to model the effect of the protective cap on the acoustic response of a MEMS microphone
Homentcovschi D, Miles RN, Loeppert PV and Zuckerwar AJ
An analysis is presented of the effect of the protective cover on the acoustic response of a miniature silicon microphone. The microphone diaphragm is contained within a small rectangular enclosure and the sound enters through a small hole in the enclosure's top surface. A numerical model is presented to predict the variation in the sound field with position within the enclosure. An objective of this study is to determine up to which frequency the pressure distribution remains sufficiently uniform so that a pressure calibration can be made in free space. The secondary motivation for this effort is to facilitate microphone design by providing a means of predicting how the placement of the microphone diaphragm in the package affects the sensitivity and frequency response. While the size of the package is typically small relative to the wavelength of the sounds of interest, because the dimensions of the package are on the order of the thickness of the viscous boundary layer, viscosity can significantly affect the distribution of sound pressure around the diaphragm. In addition to the need to consider viscous effects, it is shown here that one must also carefully account for thermal conductivity to properly represent energy dissipation at the system's primary acoustic resonance frequency. The sound field is calculated using a solution of the linearized system consisting of continuity equation, Navier-Stokes equations, the state equation and the energy equation using a finite element approach. The predicted spatial variation of both the amplitude and phase of the sound pressure is shown over the range of audible frequencies. Excellent agreement is shown between the predicted and measured effects of the package on the microphone's sensitivity.
A water-immersible 2-axis scanning mirror microsystem for ultrasound andha photoacoustic microscopic imaging applications
Huang CH, Yao J, Wang LV and Zou J
Fast scanning is highly desired for both ultrasound and photoacoustic microscopic imaging, whereas the liquid environment required for acoustic propagation limits the usage of traditional microelectromechanical systems (MEMS) scanning mirrors. Here, a new water-immersible scanning mirror microsystem has been designed, fabricated and tested. To achieve reliable underwater scanning, flexible polymer torsion hinges fabricated by laser micromachining were used to support the reflective silicon mirror plate. Two efficient electromagnetic microactuators consisting of compact RF choke inductors and high-strength neodymium magnet disc were constructed to drive the silicon mirror plate around a fast axis and a slow axis. The performance of this water-immersible scanning mirror microsystem in both air and water were tested using the laser tracing method. For the fast axis, the resonance frequency reached 224 Hz in air and 164 Hz in water, respectively. The scanning angles in both air and water under ±16 V DC driving were ±12°. The scanning angles in air and water under ±10 V AC driving (at the resonance frequencies) were ±13.6° and ±10°. For the slow axis, the resonance frequency reached 55 Hz in air and 38 Hz in water, respectively. The scanning angles in both air and water under ±10 V DC driving were ±6.5°. The scanning angles in air and water under ±10 V AC driving (at the resonance frequencies) were ±8.5° and ±6°. The feasibility of using such a water-immersible scanning mirror microsystem for scanning ultrasound microscopic imaging has been demonstrated with a 25-MHz ultrasound pulse/echo system and a target consisting of three optical fibers.
An optimised silicon piezoresistive microcantilever sensor for surface stress studies
Ansari MZ and Cho C
Surface stress is a versatile and efficient means to study various physical, chemical, biochemical and biological processes. This work focuses on developing high sensitive piezoresistive microcantilever designs to study surface stress. The cantilevers are made of silicon with rectangular holes at their base that also circumscribe a piezoresistor sensing element. To find the optimum design, the effects of change in cantilever width, rectangular hole length and type of dopant on mechanical properties like deflection, frequency and maximum stress are characterised using finite element analysis software. The surface stress sensitivity characteristics of the different cantilever designs is ascertained by applying a surface stress on their top surfaces. Results show that the sensitivity is increased by increasing the cantilever width as well as the length of the hole and the sensitivity of p-type designs is more than two times the n-type.
Parametric study of 3D printed microneedle (MN) holders for interstitial fluid (ISF) extraction
Taylor RM, Maharjan D, Moreu F and Baca JT
The need for novel, minimally invasive diagnostic, prognostic, and therapeutic biomedical devices has garnered increased interest in recent years. Microneedle (MN) technology has stood out as a promising new method for drug delivery, as well as extraction of interstitial fluid (ISF). ISF comprises a large portion of the extracellular fluid in living organisms yet remains inadequately characterized for clinical applications. Current MN research has focused on the fabrication of needles with different materials like silicone, carbon, and metals. However, little effort has been put forth into improving MN holders and patches that can be used with low cost MNs, which could effectively change how MNs are attached to the human body. Here, we describe different 3D-printed MN holders, printed using an MJP Pro 2500 3D printer, and compare the ISF extraction efficiencies in CD Hairless rats. We varied design parameters that may affect the skin-holder interface, such as throat thickness, tip curvature, and throat diameter. MN arrays, with insertion depths of 1500 μm, had extraction efficiencies of 0.44 ± 0.35, 0.85 ± 0.64, 0.32 ± 0.21, or 0.44 ± 0.46 µl/min when designed with flat, concave, convex, or bevel profile geometries, respectively. Our results suggest ISF extraction is influenced by MN holder design parameters and that a concave tip design is optimal for extracting ISF from animals. The future direction of this research aims to enable a paradigm in MN design that maximizes its efficiency and engineering performance in terms of volume, pressure, and wearability, thereby automatizing usage and reducing patient intervention to ultimately benefit remote telemedicine.
Temporal response of biochemical and biological sensors with bimodal surface adsorption from a finite sample
Jokić I, Jakšić O, Frantlović M, Jakšić Z, Guha K and Rao KS
The importance of adsorption-based biochemical/biological sensors in biochemistry and biophysics is paramount. Their temporal response gives information about the presence of a biochemical/biological analyte, its concentration and its interactions with the adsorption sites (which may be an integral part of the surface itself or immobilized functionalizing molecules). Mathematical models of the temporal response taking into account as many relevant effects as possible are essential for obtaining reliable information. We present a novel model taking into account the bimodal affinity of a sensing surface (adsorption occurs on two distinct site types), and the adsorption-caused depletion of the analyte from the sample. We perform qualitative and quantitative analysis of the analyte depletion influence on the bimodal adsorption, and of the influence of the sensing surface inhomogeneity on the sensor temporal response, for different analyte concentrations and different fractions of two types of adsorption sites. Since the presented mathematical model deals with the realistic cases of the sensing surface non-uniformity and the finite amount of analyte present in the sensor reaction chamber, it enables improved accuracy in interpreting the measurement data. Our results are general, i.e. valid for any adsorption sensor (microcantilevers, plasmonics) and for arbitrary sensor dimensions.
Analysis of robust control method for the flexible manipulator in reliable operation of medical robots during COVID-19 pandemic
Jayaswal K, Palwalia DK and Kumar S
A novel coronavirus disease (COVID-19) is transmitting throughout the globe. During this Pandemic situation, medical robots are playing an important role in protecting front line medical staff from this disease. The flexible robotic manipulator has mechanical flexibility, due to that fluctuation or oscillations can be seen either during or after the movement of a manipulator and can create uncertainty in medical operations. During this pandemic situation, reliable operations of these robots are necessary that depend upon the stability of flexible manipulators. In this article, Linear Quadratic Regulator (LQR), Pole Placement, and Proportional-Integral-Derivatives (PID) control methods have been used to investigate the robust control method for controlling the position of manipulator with flexible link in medical robots. To carry out this research, an effective variant of the flexible Link robotic manipulator has been used as a framework to analyze the robust control method. The Matlab®/Simulink result shows that the LQR control method provides better control response compared to PID and pole placement method and thus provides reliable operation to Medical Robots.
A proposal for testing kit of corona viruses using 3D photonic structure
Mohanty SK, Das S, Swain KP, Bhanja U and Palai G
Design of corona virus testing kit is proposed in this paper using silicon based 3D photonic structure through zirconium quantum dot solution at the signal of 412 nm. The principle of measurement depends on the computation of reflectance, absorbance and transmittance of virus based quantum dot solution. In this paper, the reflectance is studied through the analysis of photonic band gap and absorbance is made through its numerical treatment. Further, the numerical investigation shows that the transmitted energy through photonic structure would determine the type of corona virus. For example; if the transmitted energy lies within the visible spectrum the sample would be normal corona virus. However, the sample could be IBV (SARS COV-2) if the transmitted energy would be Infrared.
Realization of novel corona virus kit using silicon based 2D photonic structure via finite difference time domain method
Sethi KK, Boobhalon V, Sahu SK and Palai G
The present research proposes the novel corona virus kit using silicon based two (2D) photonic structure. The basic principle of the estimation of different corona viruses relies on the computation of reflectance, absorbance, and transmittance at the signal of 412 nm. Here reflectance is investigated through the analysis of photonic band gap where absorbance is calculated using analytical treatment. The present investigation is made for different corona virus such as N5H1, N5H2, H9N2, H4N6, FAdV, and IBV. The numerical analysis indicates that the sample could be affected by novel corona virus if the transmitted signal lies with red spectrum. Similarly, sample could be normal viruses if the transmitted signal would green spectrum.
External temperature sensor assisted a new low power photoplethysmography readout system for accurate measurement of the bio-signs
Pandey RK and Chao PC
This study presents an external temperature sensor assisted a new low power, time-interleave, wide dynamic range, and low DC drift photoplethysmography (PPG) signal acquisition system to obtain the accurate measurement of various bio signs in real-time. The designed chip incorporates a 2-bit control programmable transimpedance amplifier (TIA), a high order filter, a 3:8 programmable gain amplifier (PGA) and 2 × 2 organic light-emitting diode (OLED) driver. Temperature sensor is used herein to compensate the adverse effect of low-skin-temperature on the PPG signal quality. The analog front-end circuit is implemented in the integrated chip with chip area of 2008 μm × 1377 μm and fabricated via TSMC T18 process. With the standard 1.8 V, the experimental result shows that the measured current sensing range is 20 nA-100 uA. The measured dynamic range of the designed readout circuit is 80 dB. The estimated signal to noise ratio is 60 dB@1 uA, and the measured input referred noise is 60.2 pA/Hz. The total power consumption of the designed chip is 31.32 µW (readout) + 1.62 mW (OLED driver@100% duty cycle). The non-invasive PPG sensor is applied to the wrist artery of the 40 healthy subjects for sensing the pulsation of the blood vessel. The experimental results show that for every 1 °C decrease in mean ambient temperature tends to 0.06 beats/min, 0.125 mmHg and 0.063 mmHg increase in hear rate (HR), systolic (SBP) and diastolic (DBP), respectively. Similarly, for every 1 °C increase in mean ambient temperature tends to 0.13 beats/min, 0.601 mmHg and 0.121 mmHg increase in HR, SBP and DBP, respectively. The measured accuracy and standard error for the HR estimation are 96%, and - 0.022 ± 2.589 beats/minute, respectively. The oxygen stauration (SO) measurement results shows that the mean absolute percentage error is less than 5%. The resultant errors for the SBP and DBP measurement are - 0.318 ± 5.19 mmHg and - 0.5 ± 1.91 mmHg, respectively.
Microfluidic ratio metering devices fabricated in PMMA by CO laser
Tweedie M and Maguire PD
We describe microfluidic fabrication results achieved using a 10.6 μm CO engraving laser on cast PMMA, in both raster and vector mode, with a 1.5″ lens and a High Power Density Focussing Optics lens. Raster written channels show a flatter base and are more U-shaped, while vector written channels are V shaped. Cross-sectional images, and, where possible, stylus profilometry results are presented. The sides of V-grooves become increasing steep with laser power, but broader shallower channels may be produced in vector mode by laser defocus, as illustrated. Smoothing of raster engraved channels by heated IPA etch, and transparency enhancement by CHCl vapour treatment are briefly discussed. An asymmetric Y meter is discussed as one method of diluting acid into seawater for dissolved CO analysis. Alternatively, microfluidic snake channel restrictors of different lengths in 2 channels may achieve the same result. Samples are fabricated with bases bonded by CHCl vapour treatment, and the devices are flow tested with either dilute food dye or DI water. Microfluidics fabricated in this manner have applications in ocean sensing of dissolved CO and other analytes, as well as broader sensing measurements, including biomedical sensors.
The status and perspectives of nanostructured materials and fabrication processes for wearable piezoresistive sensors
Chiappim W, Fraga MA, Furlan H, Ardiles DC and Pessoa RS
The wearable sensors have attracted a growing interest in different markets, including health, fitness, gaming, and entertainment, due to their outstanding characteristics of convenience, simplicity, accuracy, speed, and competitive price. The development of different types of wearable sensors was only possible due to advances in smart nanostructured materials with properties to detect changes in temperature, touch, pressure, movement, and humidity. Among the various sensing nanomaterials used in wearable sensors, the piezoresistive type has been extensively investigated and their potential have been demonstrated for different applications. In this review article, the current status and challenges of nanomaterials and fabrication processes for wearable piezoresistive sensors are presented in three parts. The first part focuses on the different types of sensing nanomaterials, namely, zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) piezoresistive nanomaterials. Then, in second part, their fabrication processes and integration are discussed. Finally, the last part presents examples of wearable piezoresistive sensors and their applications.
Assessing the electricity energy efficiency of university campus exterior lighting system and proposing energy-saving strategies for carbon emission reduction
Kerem A
This paper presents efficiencies research and energy-saving strategies for carbon emission reduction of the exterior lighting system of Avşar Campus of Kahramanmaraş Sütçü İmam University, Turkey. Once the campus's average energy consumption for the previous five years was calculated, it was found to be 18,802 Megawatt hour/year (MWh/year), with 6,203 carbon dioxide (CO) tons/year emissions. Also, the annual electrical energy consumption for exterior lighting was calculated as 670,395 MWh/year, with annual emissions of 221,170 CO tons/year. Inefficient lamp choices in exterior lighting systems and longer than necessary operating times have been identified as the causes of these high values. That's because High-Pressure Sodium (HPS) lamps with an installed power of 109,050 Kilowatt (kW), which have a low efficiency but a high energy consumption, provide for 70% of exterior lighting. Thus, seven unique energy-saving strategies have been designed with the aim of decreasing total energy consumption and achieving more cost savings as well as less harmful emissions released into the atmosphere. All of the strategies were designed under the following three headings: dimming method, optimization of lamps' operation times, and retrofitting lamps with new and technological ones. The study's novelty lies in the creation of seven unique energy-saving strategies for the first time in light of the three headings highlighted, as well as their adjustment to a sophisticated campus with such high energy consumption. Once all of the proposed strategies are compared to the current system, it has been discovered that strategy-7 saves 81.656% energy consumption (547,418 MWh/year), 180,599 CO tons/year saving, and € 49,268 (€/year) cost-saving. Such a low energy consumption is vital for a rapidly growing and expanding campus in terms of carbon emissions, cost savings, and environmental quality.