In the present paper three dimensional magnetohydrodynamic (MHD) flow and heat transfer analysis associated with thermal radiation as well as viscous dissipation of nanofluid over a shrinking surface ...has been investigated. The developed governing equations are transformed employing suitable transformations which are then solved by Homotpy analysis method (HAM). The study of all governing parameters such as magnetic, permeability, wall mass transfer, radiation, nanoparticle volume fraction and shrinking parameters along with Eckert and Biot's numbers is carried out and the representative results are provided to explore the effect of these pertinent parameters on the fluid velocity and temperature as well as the local skin friction and local Nusselt number. The major outcome of the present study is that the magnetic field and porous matrix both impede the fluid motion, along with reduction in the velocity gradient at the wall thereby reducing local skin friction and thermal radiation as well as viscous dissipation effects show a reduction in the rate of heat transfer from the shrinking surface.
•Homotopy Analysis Method for 3D MHD flow of nanofluid.•A novel idea of inclusion of thermal radiation as well as viscous dissipation which is not yet explored for 3D MHD nanofluid by shrinking surface.•Comparative study with previously published results is incorporated.
Crash sensing and its assessment play a pivotal role in autonomous vehicles for preventing fatal casualties. Existing crash sensors are severely bottlenecked by sluggish response time, rigid ...mechanical components, and space constraints. Miniaturized sensors embedded with custom‐tailored nanomaterials upholds potential to overcome these limitations. In this article, piezoelectric Zinc‐Oxide thin film as a crash sensing layer is integrated onto a flexible metal‐alloy cantilever. Material characterization studies are conducted to confirm piezoelectric property of sputtered ZnO film. The piezoelectric d
31 coefficient value of ZnO film was 7.2 pm V–1. The ZnO sensing element is firmly mounted on a scaled car model and used in a crash sensing experimental set‐up. A comprehensive theoretical analysis for two different real scenarios (nearly elastic and nearly inelastic collision) of crash events followed by experimental study is discussed. The crash sensor's output exhibits a linear relationship with magnitude of impact forces experienced at crash events. The response time of ZnO crash sensor is 18.2 ms, and it exhibits a sensitivity of 28.7 mV N–1. The developed crash sensor has potential to replace bulk material sensors owing to its faster response time, high sensitivity, and compactness as the demand for crash sensors in next‐generation automobile industries is progressively growing.
Crash sensing and its assessment is of utmost importance for occupant's safety during vehicular accidents. The present article reports on custom‐tailoring of piezoelectric Zinc‐Oxide films for crash sensing. Material characterization studies confirmed the piezoelectric property of Zinc‐Oxide films. The developed crash sensor is mounted on a scaled car model, and the output voltage signals exhibited linear dependence with the forces experienced during crash events.
In the present study, the main concern is to investigate the magnetohydrodynamic nanofluid flow subject to porous matrix and convective heating past a permeable linear stretching sheet. In addition, ...the influence of velocity slip, viscous dissipation, Joule heating and non-linear thermal radiation are considered. A new micro-convection model known as the Patel model is implemented for considerable enhancement of the thermal conductivity and hence, the heat transfer capability of nanofluids. Moreover, a convective heat transfer model is introduced where the bottom surface of the sheet gets heated due to a convection mechanism from a hot fluid of particular temperature. The numerical results of the transformed governing differential equations have been obtained by using fourth-order Runge–Kutta method along with shooting approach and secant method is used for better approximation. In the present analysis, base fluids such as water and Ethylene glycol and Copper, Silver and Aluminum oxide nanoparticles are considered. Results of the present investigation show that inclusion of porous matrix contributes to slow down the fluid velocity and diminution of wall shear stress (axial as well as transverse). Drag force due to magnetic field strength, velocity slip and imposed fluid suction impede the fluid motion and upsurge the heat transfer rate from the surface. In addition, rise in viscous dissipation widens the thermal boundary layer.
Essentials The main receptor for platelet glycoprotein (GP) Ibα is von Willebrand factor (VWF). P-selectin and thrombospondin-1 (TSP1) have been suggested as counter receptors for GPIbα. In a laser ...injury model, P-selectin promotes thrombus propagation independently of VWF and TSP1. In a laser injury model, thrombus persists in interleukin-4 receptor α/GPIbα-transgenic mice.
Background P-selectin and thrombospondin-1 (TSP1) have been suggested as counter ligands that may mediate GPIbα-dependent thrombus growth independently of von Willebrand factor (VWF) in vitro. However, residual thrombus formation still persists in Vwf
Tsp1
mice, suggesting existence of other mechanisms that modulate thrombus propagation. Objective We determined whether P-selectin modulates thrombus propagation in injured arterioles independently of TSP1 and VWF. Methods CD-62P blocking antibody in Vwf
Tsp1
mice was used to inhibit P-selectin. We determined thrombus growth kinetics in two models of thrombosis: FeCl
injury-induced and laser injury-induced thrombosis. Results In a 10% FeCl
injury-induced thrombosis model, the initial platelet adhesion, time to form first thrombus, and non-occlusive residual thrombus growth kinetics were comparable between P-selectin-blocking antibody-treated Vwf
Tsp1
mice and control IgG-treated Vwf
Tsp1
mice. On the other hand, in a laser injury-induced thrombosis model, residual thrombus growth kinetics were significantly decreased in P-selectin-blocking antibody-treated Vwf
Tsp1
mice vs. control IgG-treated Vwf
Tsp1
mice. Because P-selectin has been suggested as a counter ligand for platelet GPIbα, we determined the role of GPIbα in a laser injury-induced thrombosis model. Surprisingly, in a laser injury model, unlike in a FeCl
injury model, thrombus formation was not completely inhibited in IL4Rα/GPIbα-tg mice. Residual thrombus growth kinetics were comparable between P-selectin-blocking antibody-treated IL4Rα/GPIbα-tg mice and control IgG-treated IL4Rα/GPIbα-tg mice. Comparison of slopes over time showed that residual thrombus growth kinetics were comparable in P-selectin-blocking antibody-treated Vwf
Tsp1
and control IgG-treated IL4Rα/GPIbα-tg mice Conclusion In a laser injury-induced thrombosis model, P-selectin modulates thrombus propagation independently of VWF and TSP1.
We report on the systematic comparative study of highly c-axis oriented and crystalline piezoelectric ZnO thin films deposited on four different flexible substrates for vibration sensing application. ...The flexible substrates employed for present experimental study were namely a metal alloy (Phynox), metal (aluminum), polyimide (Kapton), and polyester (Mylar). ZnO thin films were deposited by an RF reactive magnetron sputtering technique. ZnO thin films of similar thicknesses of 700 ± 30 nm were deposited on four different flexible substrates to have proper comparative studies. The crystallinity, surface morphology, chemical composition, and roughness of ZnO thin films were evaluated by respective material characterization techniques. The transverse piezoelectric coefficient (d 31) value for assessing the piezoelectric property of ZnO thin films on different flexible substrates was measured by a four-point bending method. ZnO thin films deposited on Phynox alloy substrate showed relatively better material characterization results and a higher piezoelectric d 31 coefficient value as compared to ZnO films on metal and polymer substrates. In order to experimentally verify the above observations, vibration sensing studies were performed. As expected, the ZnO thin film deposited on Phynox alloy substrate showed better vibration sensing performance. It has generated the highest peak to peak output voltage amplitude of 256 mV as compared to that of aluminum (224 mV), Kapton (144 mV), and Mylar (46 mV). Therefore, metal alloy flexible substrate proves to be a more suitable, advantageous, and versatile choice for integrating ZnO thin films as compared to metal and polymer flexible substrates for vibration sensing applications. The present experimental study is extremely important and helpful for the selection of a suitable flexible substrate for various applications in the field of sensor and actuator technology.
Psychedelic-assisted treatment is at first glance markedly different in structure and approach from mainstream forms of psychotherapy in the West. A major criticism of clinical psychedelic research ...rests on the difficulty of executing placebo-controlled studies and distinguishing drug effects from those of the psychotherapeutic container in which psychedelics are typically presented. Detractors also tend to find fault in spiritual or mystical themes that often arise in the context of psychedelic use. Common factors theory of psychotherapy is a useful and extensively studied framework that can help make sense of these issues, and has much to contribute to our understanding of contextual effects that are often discussed in psychedelic literature as “set and setting.” In this article, we examine four major contextual “common factors” shared by various healing traditions: 1) the therapeutic relationship; 2) the healing setting; 3) the rationale, conceptual scheme, or myth; and 4) the ritual. We explain how these factors show up in psychedelic-assisted treatment and how they may contribute to therapeutic effects. Lastly, we discuss the implications of these factors for the concept of placebo, and for future research.
We report the realization of strain gauges prepared by screen-printing the graphite powder-printing ink dispersion on a flexible glass substrate. Furthermore, the significant features of these films ...can have numerous real-time potential applications (pressure sensors, load cells, level sensors, weigh bridges, displacement sensors, crack sensors, strain sensors etc.) in various fields such as automotive, aerospace, biomedical, oceanography, weather forecasting and industrial purposes. Graphite flakes in the powder are found to have irregular shape and size. However, maximum size of the flake does not exceed 20μm but, particles of 2μm to 5μm were observed often. Thickness of screen-printed films varied in the range 13–27μm. Tunable gauge factors (GFs) ranging from 17 up to 70 were achieved. Accordingly, sensitivity of the strain gauges varied from 0.8206 Ω/με to 0.996 Ω/με. The variation in GF is found to be less than 2%. Maximum hysteresis and nonlinearity were observed to be less than 2% FSO (Full Scale Output). Repeatability is found to be minimum 98%. The dispersion composition is tuned to obtain a better sensitivity. Regarding temperature effects, all the strain gauge samples exhibited a negative value of TCR, lowest being -2×10−4 /ºC. Calculated gauge factors were much higher than the gauge factor of metal foil strain gauges, semiconductors and other recently used materials like graphene, MWCNTs and other carbon variants like amorphous carbon reported in the literature. In the present work, strain sensors having high gauge factor values with a linear behavior were easily fabricated using commonly available materials. They were stable, robust, cost effective and safely disposable. The electrical resistance of printed films can also change with moisture, chemical, biological and mechanical properties and this mechanism can be used to measure various parameters.
Display omitted
•Successfully studied & tailored the graphite dispersion-based strain sensors. Strain sensing composites are formulated by dispersing graphite powder in printing ink and, piezoresistive strain gauges are fabricated by employing screen printing technology.•Expensive process and clean room facilities are not required.•Exhibited higher gauge factor and hence sensitivity. Notable repeatability, lower hysteresis and linear behavior w.r.to strain observed.•Options for different substrates such as flexible/nonflexible polymers, electrically insulated metals/metal alloys, apparel/cloths and papers etc.•An overview of cost effective strain gauges.
The present work aims at fabrication and characterization of the novel dispersion based piezoresistive strain gauges. The novelty of present work is in the material-set and technique used to synthesize the low-cost, graphite powder based composites of various proportions without the need for additional pre-treatment or functionalization. When filler and resins are properly formulated, they can be printed in variety of shapes over different substrates such as glass, acrylic, plastics (such as PVC, PDMS, PMMA, PET, PI), metal foils, paper etc. They may be of great interest to integrate mechanical, chemical or temperature sensing functions in many electronic circuits and devices. In the current work, the resistive composite dispersions are screen-printed on glass substrate to fabricate the strain gauges and to study their piezoresistive strain performance. Graphite particles in the powder are found to have irregular shape and size. Thickness of screen-printed films varies in the range 13–27μm. Gauge factors ranging from 17 up to 70 is achieved for the strain gauges having satisfactory stability, linearity and repeatability. The variation in GF is found to be less than 2%. Maximum hysteresis and nonlinearity were observed to be less than 2% FSO (Full Scale Output). Repeatability is found to be minimum 98%. The dispersion composition is tuned to obtain a better sensitivity. Regarding temperature effects, all the strain gauge samples exhibited a negative value of TCR, lowest being -2×10−4 /ºC. Graphite powder and printing ink are inexpensive and commercially-available. Also, technique used to fabricate strain gauges avoids high-end equipment and expensive clean room facilities. These devices are robust, easy to scale & pattern, safely disposable strain gauges with are fairly good performance fabricated at low cost. These features make them a good candidate for pressure sensors, weigh bridges, displacement sensors, crack sensors, strain sensors etc. The real time potential applications are in different sectors such as automotive, aerospace, biomedical, oceanography and industrial purposes.
Display omitted
•Fabrication method for an array of hollow tapered Si microneedles is presented.•Si microneedles biocompatibility is increased by coating Ti &Au.•The breaking force of fabricated ...microneedles is 10 times above the skin resistive force.•Flow rate variation through microneedles with respect to different inlet pressure is studied.
In this paper, we present the fabrication and characterization of Ti and Au coated hollow silicon microneedles for transdermal drug delivery applications. The hollow silicon microneedles are fabricated using isotropic etching followed by anisotropic etching to obtain a tapered tip. Silicon microneedle of 300μm in height, with 130μm outer diameter and 110μm inner diameter at the tip followed by 80μm inner diameter and 160μm outer diameter at the base have been fabricated. In order to improve the biocompatibility of microneedles, the fabricated microneedles were coated with Ti (500nm) by sputtering technique followed by gold coating using electroplating. A breaking force of 225N was obtained for the fabricated microneedles, which is 10 times higher than the skin resistive force. Hence, fabricated microneedles can easily be inserted inside the skin without breakage. The fluid flow through the microneedles was studied for different inlet pressures. A minimum inlet pressure of 0.66kPa was required to achieve a flow rate of 50μl in 2s with de-ionized water as a fluid medium.
The research toward high-performing pressure sensors has been going on for more than two decades, with the goal of improving key parameters, namely the high gauge factor (GF) and device stability for ...future applications. In the present work, the piezoresistivity of the polycrystalline molybdenum disulfide (MoS2) is harnessed for pressure sensing applications with very low noise levels. The fabricated microelectromechanical systems (MEMS) pressure sensor exhibits a high GF of ~92 with pressure sensitivity of ~<inline-formula> <tex-math notation="LaTeX">0.46 \mu \text{A} </tex-math></inline-formula>/Pa and a low nonlinearity of ~12% in the applied pressure range 0-20 kPa. This exceptional performance is explained based on fluctuation-induced tunneling in the polycrystalline MoS2-based pressure sensor. The tunneling barrier between two grains gets modified with the application of external pressure. Furthermore, the noise analysis of the fabricated MEMS pressure sensor shows that the noise level gets altered with the applied stress due to the modified barrier potential.
PDF
