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A capacitive micromachined ultrasonic transducer (CMUT) due to many benefits is being considered as an imaging and therapeutic technology recently. The critical challenge here is to stabilize the system beyond the pull-in voltage considering imposed perturbations. The CMUT system, on the other hand, has a low range of travel and it is intrinsically unstable, which can result in a pull-in phenomenon. Consequently, in order to use the CMUT systems in a variety of medical applications that require high tuning ratio, a closed-loop control technique has been designed for these systems aims at increasing the maximum capacitance and enhancing tunability as well. In this study, using the closed-loop control, the resistance of micro plate against the pull-in phenomenon has been examined. Also, in the description of the system a more accurate nonlinear modeling has been considered in the presence of an under-actuated sliding model control strategy with finite convergence time. Beside, adaptive protocols with unknown upper bounds have been designed to compensate the effects of uncertainty, unmodeled dynamics and external disturbances. The performance of controller in terms of improving output pressure, stabilizing the CMUT and its robustness to imposed perturbations have been investigated. Finally, numerical simulations are presented to verify the usefulness and applicability of the proposed control strategy.

Ionic liquids are a significant type of organic salts with attractive and superior physicochemical features for employing in a number of chemical processes. Ionic liquids include one large and asymmetric cationic or anionic functional group. The properties of cationic functional group are almost similar and it is main motivation of this study. In the present investigation, we extended various semi-empirical correlations to predict some temperature-based properties of ionic liquids mixture (IL-mixture). These properties are density, viscosity, surface tension and bubble point pressure. In the case of IL-mixture density, modified Rackett equation and Taylor equation with three scenarios, modified Gardas and Coutinho equation were considered and the obtained results were compared with Peng-Robinson equation of state (EoS), Patel-Teja EoS and perturbed-chain statistical associating fluid theory EoS. In the case of IL-mixture viscosity, two types of activation energy concept models were used and also, Lee-Kesler method and modified Brock and Bird were applied to predict IL-mixture bubble point pressure and IL-mixture surface tension, respectively. A used dataset was collected from reliable literature including 2731 data points of bubble pressure (23 binary system), 4643 data points of density (102 binary system), 1011 data points of viscosity (32 binary system) and 391 data points of surface tension (16 binary system). These data relevant to 12 cation-family and 36 solvents. The all of the data was haphazardly separated in two subsets of train and test with a computer program. The obtained results indicated all used semi-empirical correlations gives the best match with corresponding experimental data and the values of statistical parameters demonstrated this hypothesis.

Peritoneal metastasis is an advanced cancer type which can be treated with pressurized intraperitoneal aerosol chemotherapy (PIPAC). Here, chemotherapeutics are nebulized under high pressure in the intraperitoneal (IP) cavity to obtain a better biodistribution and tumor penetration. To prevent the fast leakage of chemotherapeutics from the IP cavity, however, nebulization of controlled release formulations is of interest. In this study, the potential of the thermosensitive hydrogel Pluronic F127 to be applied by high pressure nebulization is evaluated. Therefore, aerosol formation is experimentally examined by laser diffraction and theoretically simulated by computational fluid dynamics (CFD) modelling. Furthermore, Pluronic F127 hydrogels are subjected to rheological characterization after which the release of fluorescent model nanoparticles from the hydrogels is determined. A delicate equilibrium is observed between controlled release properties and suitability for aerosolization, where denser hydrogels (20% and 25% w/v Pluronic F127) are able to sustain nanoparticle release up to 30 hours, but cannot effectively be nebulized and vice versa. This is demonstrated by a growing aerosol droplet size and exponentially decreasing aerosol cone angle when Pluronic F127 concentration and viscosity increase. Novel nozzle designs or alternative controlled release formulations could move intraperitoneal drug delivery by high pressure nebulization forward.

In this study, hydrostatic cyclic extrusion compression (HTCEC) is introduced as a novel severe plastic deformation technique for producing the relatively long and large ultrafine grained (UFG) and nano-grained tubes. In HTCEC technique, the utilization of pressurized hydraulic fluid between the piece and the die leads to the reduction of the friction force and the required processing load. All of these conditions facilitate the processing of the long and large tubes. Also, during HTCEC process, a movable mandrel is placed inside the hollow tube, which plays a main role in the reduction of the required hydrostatic pressure. To investigate the efficiencies of HTCEC process, aluminum 5052 alloy tubes were processed by HTCEC up to two passes. Then, the mechanical properties and microstructure evolution were examined. After the first pass of HTCEC, tangled and diffused arrangements of dislocations were formed. Then, the second pass of HTCEC resulted in a more refined and more homogeneous UFG microstructure with an average subgrain size of 636 nm, while the average grain size of the initial sample was ~ 360 μm. Tensile tests and hardness measurements revealed that two passes of HTCEC led to an increase in the yield strength from 98 MPa to 254 MPa (~ 2.6 times higher), the ultimate strength from 178 MPa to 306 MPa (~ 1.72 times higher) and the microhardness from ~ 56 to ~ 120 Hv (~ 2.14 times higher). Simultaneously, a decrease in the elongation to failure from 31.6 to 15.4% was observed, which is a small amount compared to the results of other studies. Also, in comparison to one-pass, a more homogeneous microhardness distribution through the thickness was detected in the two-pass processed tube. Fractography evaluations by SEM indicated that predominantly ductile fracture occurred in all samples. Furthermore, the equivalent strain and the pressing load of HTCEC process was evaluated by FEM simulation. It seems that HTCEC process, by utilizing its potentials, can produce the relatively long and large UFG tubes having a simultaneous high strength and good ductility.

The present study aimed to numerically simulate the rapid expansion of the supercritical solution (RESS) process including particle generation, hydrodynamics, and solving the population balance equation (PBE) to predict the particle-size distribution (PSD) of solid-supercritical carbon dioxide binary systems. Energy, momentum, and mass equations, in addition to the extended generalized Bender equation of state (EoS), were applied to predict the hydrodynamic behavior of a supercritical solution under several operating conditions using a nozzle and expansion vessel. The tetraphenylporphyrin (TBTPP) solubility in supercritical carbon dioxide was calculated using the Peng–Robinson EoS/Kwak–Mansoori as a mixing rule. Subsequently, TBTPP, aspirin, ibuprofen, and salicylic acid nucleation as well as the supersaturation rate were calculated. Finally, we solved the time dependence of the parameters of the size distribution numerically. The established models are compared over a wide parameter range using a reference model that refers to the method of moment log-normal size distribution functions through the RESS process to predict a solid PSD. The results obtained are presented with and without coagulation phenomena. The average absolute percent deviation of solubility of TBTPP was 3.98, and the hydrodynamic behavior of supercritical carbon dioxide showed a similar trend as the results presented in the published research work. Furthermore, a particle size distribution prediction using coagulation showed acceptable agreement with the experimental PSDs.

This paper deals with the investigation of nonlinear static pull-in instability of smart Nano-switches regarding the new size-dependent phenomenon, known as flexoelectricity, together with the surface effects. It is noteworthy that the coupling effect of the flexoelectricity and surface elasticity on nonlinear static pull-in instability of electrostatically-actuated Nano-switches has not been studied before. Euler-Bernoulli beam assumptions in conjunction with the von-Karman nonlinearity are considered to formulate the problem. The Nano-switch is subjected to electrostatic actuation force with fringing field effect as well as Casimir force. Refined constitutive relations for piezoelectric materials capturing the flexoelectric effects are taken into consideration for mathematical modeling. Additionally, a surface elasticity approach is employed to reach an accurate model for the system. Considering the imposed electric boundary conditions, Gauss’s equation is solved to acquire the electric potential distribution along with the thickness of the Nano-switch. Thereafter, Hamilton’s principle is hired to derive the coupled nonlinear governing equations of the system. Utilizing the differential quadrature method (DQM), the nonlinear ordinary differential equations are transformed into a system of nonlinear algebraic equations. Consequently, Newton-Raphson method is exploited as a numerical method to solve the obtained algebraic equations which leads to the pull-in voltage. Investigating the maximum displacement of the Nano-switch in response to the applied electrostatic force, the effects of various involved parameters such as flexoelectricity and surface elasticity on pull-in instability are explored in detail. Furthermore, the size-dependent behavior of the pull-in instability against the flexoelectric, surface effects and applied piezoelectric voltage is analyzed. Totally, it is revealed that the flexoelectricity may exhibit a substantial influence on the pull-in behavior of smart Nano-switches, especially for some cases with small thicknesses. Therefore, this effect should be taken into account to reach an accurate, reliable and optimized design for Nano-switches.

Capability of a novel severe plastic deformation (SPD) method of hydrostatic cyclic extrusion compression (HCEC) for processing of hcp metallic rods with high length to diameter ratios was investigated. The process was conducted in two consecutive cycles on the AZ91 magnesium alloy, and microstructural evolution, mechanical properties and corrosion behavior were investigated. The results showed that the HCEC process was successively capable of producing ultrafine-grained long magnesium rods. Its ability in improving strength and ductility simultaneously was also shown. The ultimate tensile strength and elongation to failure of the sample after the second cycle of the process were improved to be 2.46 and 3.8 times those of the as-cast specimen, respectively. Distribution of the microhardness after the second cycle was uniform and its average value was increased by 116%. The potentials derived from the polarization curves were high and the currents were much low for the processed samples. Also, the diameter of the capacitive arcs derived from the Nyquist curves was large in the HCEC processed samples. The finite element analysis indicated the independency of HCEC load from the length in comparison to the conventional CEC. HCEC is a unique SPD method, which can produce long ultrafine-grained rods with a combination of superior mechanical and corrosion properties.

In this work, novel 2-mercaptoethanol capped zinc sulfide (ZnS) quantum dots (QDs) embedded polyethersulfone (PES) nanocomposite membranes were fabricated which revealed wh improved antifouling properties and dye separation performance. A simple water-based precipitation approach was used to obtain 2-mercaptoethanol capped ZnS QDs at ambient temperature. The resulting membranes were fully identified with SEM, AFM, ATR-FTIR analyses, and also underwent porosity and contact angle tests. The developed nanostructure membranes exhibited a remarkable fouling reduction in bovine serum albumin (BSA) protein filtration, as featured by a declined average surface roughness. The flux recovery ratio (FRR) was improved considerably from 52.6% for the neat PES to 87.9% for nanocomposite membrane by inserting 2 wt.% ZnS QDs. The contact angle of membrane decreased, while porosity size was enlarged by increase of the QDs loading. The prepared nanocomposite membranes showed an increased Reactive Red 195 rejection (from 91.3% to 96.1%) and an enhanced water and dye solution flux (from 121 to 163 L m−2 h−1) with respect to the bare PES membrane. Thus, the results proved the potential of the novel QDs/PES membrane for the dye separation applications.

A new severe plastic deformation (SPD) technique for improvement of the metallurgical properties of the magnesium alloys is presented. In this process, a cyclic extrusion compression angular pressing (CECAP) process is followed by an extrusion step in the outlet playing the role of additional back pressure. Therefore, more uniform and enhanced mechanical properties are expected in comparison with equal channel angular pressing (ECAP). In order to evaluate the effectiveness and capabilities of this new method, an AM60 magnesium alloy was processed. Finite element results exhibited a significant increase in strain values as well as uniform strain distribution for the new method. In addition, ~110% increase in compressive stress was observed in new method compared to the conventional ECAP. Experimental results revealed a noticeable increase in the hardness and strength of the specimens processed by the new technique as a result of the formation of finer grains and more homogeneous microstructure with good distribution of refined β-phase along the boundaries. It may be concluded that the new process is very promising for future magnesium alloy products.

Due to the importance of the usage of nano-technology based fluids in several industrial processes, the presented research deals with mathematical modeling of a comb-drive MEMS-based sensor for determinations of the physical properties of nanofluids. The proposed sensor is made up of a driving comb, sensing comb, and a sensing plate. It is actuated longitudinally via the electrostatic force created by applying an AC voltage to the driving section of the sensor. The coupled equations of the vibration of the lumped dynamic mass and the nanoscale fluid field have been derived and solved simultaneously. Frequency analysis of the dynamic model indicates that a nanofluid has inertial and damping effects on the longitudinal vibration of the structure. Therefore, the viscosity and density of a nanofluid can be measured simultaneously via the detection of the resonance frequency and resonance amplitude changes of the structure. The practical restrictions of the applied AC voltage for the linear dynamic behavior of the structure have also been presented.

Micromixers are key components of microfluidic systems for sample analysis, bioreactors, drug delivery, and many other applications. To date, numerous passive micromixer designs have been proposed. Among those, several designs with complex design structures have been demonstrated to be efficient. In the present work, the authors try to propose a new efficient design with low complexity in terms of fabrication. The new design is two-layer and is based on the split and recombination (SAR) and vortex mixing principles. It is suggested to fabricate the new design in polydimethylsiloxane (PDMS) using the soft lithography technique. This new design is chosen among three new designs simulated using the computational fluid dynamics (CFD) software ANSYS Fluent 17.0. The three new designs are named ND1, ND2, and ND3 and their mixing performances are evaluated numerically using mixing index (MI) and mixer effectiveness (ME) quantities at four different Reynolds (Re) numbers in the range of 0.1–100. Calculated values are compared with those obtained for the classical Y-shaped (CY) micromixer. Flow and mixing patterns are computed by solving the continuity, Navier–Stokes, and the convection–diffusion equations. CFD results for the CY micromixer are compared with available experimental and numerical data and reasonable agreement is observed. According to the results, ND3 has the highest performance (ME up to 36.86 percent/mm) among the investigated micromixer designs in the entire range of Re numbers. The maximum pressure drop (35099.9 Pa at Re = 100 for ND3) is still in the range of acceptable pressure drops reported in the literature. ND3 can be used as an efficient substitute for CY. Although ND3 is highly efficient (MI up to 99.52%) at Re numbers lower than 0.3 or higher than 50, its performance at the intermediate Re numbers (0.3

In this study, hydrostatic tube cyclic expansion extrusion (HTCEE) at elevated temperatures was utilized to produce relatively long ultrafine-grained (UFG) AM60 magnesium alloy tubes. HTCEE method is able to apply large strains to tubular parts and produce long UFG tubes without changing their dimensions due to the reduction of the friction at interfaces using high-pressure molten polymeric fluid at an elevated temperature. This method is performed on an AM60 magnesium alloy at an elevated temperature of 300 °C, and the microstructure and mechanical properties were examined. The results represent a significant enhancement of the mechanical properties and a dramatic reduction in the grain size. The yield and ultimate strength were increased to 160 MPa and 328 MPa after first passes of HTCEE from the primary values of 130 MPa and 212 MPa; also the elongation to failure increased to 31% from 9%. Microhardness was increased to about 72 Hv after the HTCEE process from the primary value of 50 Hv. Microstructural results showed a significant grain refinement to a grain size of ~ 3 μm after the process from the primary value of ~ 160 μm. Finite element results exhibit a very significant (~ 85% reduction) decrease in the required load and increase in the strain homogeneity in the HTCEE process compared to its conventional counterpart. This method seems to be very promising for future industrial applications.

A charge-based macromodel for small-signal ac and transient analyses of organic thin-film transistors (TFTs) is presented. Due to the comparatively small charge-carrier mobility in organic TFTs, the dynamic behavior of the gate-field-induced carrier channel is greatly affected by the frequency of the applied gate–source and drain–source voltages. The model presented here is, therefore, based on the transmission-line model and shown to reproduce the results of frequency-dependent admittance measurements and numerical simulations of the transient switching behavior of organic TFTs fabricated in the staggered architecture with good accuracy. The model has been implemented in the hardware description language Verilog-A.

This article introduces analytical compact models of short-channel effects in staggered organic thin-film transistors (TFTs). The effects of subthreshold-swing degradation, threshold-voltage roll-off, and drain-induced barrier lowering (DIBL) on the static current-voltage characteristics of staggered TFTs are extracted from an analytical potential solution of the 2-D problem of the staggered geometry. This solution is derived by using the Schwarz–Christoffel transformation that leads to a complex mapping function linking the staggered geometry to an equivalent in another coordinate system for which an analytical potential solution exists. The technology CAD (TCAD) Software Sentaurus is used to verify the compact models. Finally, the closed-form and physics-based equations are incorporated into an existing compact current model and verified by measurements on staggered organic TFTs with channel lengths as small as 0.4 $\mu \text{m}$ fabricated on flexible plastic substrates by stencil lithography.

Nanoparticles of Nd(Fe1-xCox)B with Co concentrations ranging from x = 0 to 0.5 were prepared using a modified Pechini-type sol-gel method. We have shown the influence of Co on the morphology and size of nanoparticles, as well as on elements distribution in nanostructures. It was found that nanoparticles with increased content of Fe and Co were formed during the synthesis process. There was an interdiffusion of Nd and Fe, both after oxidation and after reduction. This study helped to define promising “bottom-up” approaches for the fabrication of nanomaterials for the advanced Nd(Fe1-xCox)B permanent magnets by chemical synthesis.

The mechanical properties and microstructure of AM60 Magnesium alloy processed by a new cyclic extrusion channel angular pressing (CECAP) technique were investigated in this research. In this novel method, a low extrusion ratio stage was added at the end of the CECAP process to enhance the hydrostatic stresses and equivalent strain. The structure was refined from the average grain size of ~ 76 µm for the annealed samples to 2.63 µm in the new CECAP after four passes. While for the CECAP and ECAP processes, it was 3.43 and 6.98 µm, respectively. Experimental results of the proposed CECAP process showed an improvement in the mechanical properties after the second pass that were stopped for the ECAP process. However, the hardness of the CECAP-processed and proposed samples was constantly increasing. This increase in hardness was 196% and 175% for the proposed CECAP and CECAP processes after four passes compared to the unprocessed sample, respectively. Moreover, the compressive yield stress and ultimate compressive strength of the CECAP-processed samples were higher in all passes; however, they were smaller than those of the proposed CECAP process. The hydrostatic compressive stresses and higher plastic strain in the proposed technique helped in further refining of the grains, which can effectively improve the mechanical properties.

Zeolite, as an intricate microporous material with redox sites, has been widely examined in many chemical industries. However, zeolite is not available everywhere, and it is expensive considering the price of raw materials from which it can be synthesized. In this study, ZSM-5 zeolite, as a local silica source with the high crystallinity, was synthesized, based on diatomite exploited from a mine in the north-west of Iran. The diatomite was employed as the only source of silica, and underwent hydrothermal transformation in a Teflon-lined autoclave operating at 170 °C without any alkaline post-treatment. The effects of the reaction pH and the reaction time on the properties of the synthesized MFI-type zeolite were monitored. The hydrothermal reaction time was optimized and hierarchical ZSM-5 hexagonal crystals were obtained. Furthermore, the effect of Si/Al ratio on the crystallinity of the resulting zeolite was investigated. The XRD, SEM, TEM, BET, FTIR, TPD, TGA, and DSC analyses were carried out to characterize the synthesized zeolites. The results confirmed the creation of MFI-type zeolites from diatomite applying hydrothermal process at an optimized pH and reaction time. In addition, the synthesized ZSM-5 zeolites exhibited a narrow pore size distribution resembling the mesoporous structure of standard ZSM-5 zeolites. Plenty of regularly arranged pores with diameters of 300–500 nm were observed inside the round circle-like sections of diatomite. For zeolites in which Si/Al ratio was higher (55 compared to 37), a relatively narrower pore size distribution similar to that of the standard ZSM-5 zeolite was detected. Comparably, the synthesized zeolites also contained stronger acid sites, rendering it as an excellent catalyst for the conversion of methanol to gasoline.

Micropolar fluids as complex non-Newtonian fluids admittedly have numerous applications in various fields, especially in medicine. Blood as a micropolar fluid plays an important role in regulating the body’s system and maintaining homeostasis. Physical properties of micropolar fluids, especially their viscosity, affect their rheological behavior significantly. Therefore, measurement of viscosity of these complex fluids especially human blood seems very necessary as it is considered a key parameter in the diagnosis and treatment of several diseases. In this paper, a new comb-drive microsensor for estimation of physical properties of micropolar fluids is presented. Driving and sensing combs, a sensing plate attached to the shuttle of the resonator form the structure of the electrostatic sensor. The nonlinear dynamic behavior of the sensor due to the presence of the electrostatic force has been investigated to obtain the limitations of the linear behavior of the structure. It has been shown that calculating the resonance frequency and resonance amplitude variations of the lumped dynamic model of the sensor arising from damping and inertial effects of the fluid can lead to the determination of the physical properties of a micropolar fluid. The effects of the geometrical parameters of the sensor and the applied exciting voltage on the performance of the sensor have also been studied.

Unlike gold and silver, aluminum shows a localized surface plasmon resonance (LSPR) over a wide spectral range from ultraviolet (UV) to the visible region. Herein, we demonstrate a new process to optically couple TiO2 nanotubes (NTs) with a high-strength aluminum substrate, to achieve a synergistic enhancement of photocatalytic antibacterial effects through controlled LSPR of aluminum. The high-strength aluminum substrate was produced by tubular channel angular pressing (TCAP). Their LSPR was tailored through the formation of superficial nano-concave arrays (NCAs) with desired concave diameters. A layer of aligned TiO2 NTs was fabricated on the surface of aluminum nano-concave arrays (Al NCAs) by anodization of a thin film of titanium. When the diameter of Al NCAs reached ~80 nm, a strong LSPR near the optical bandgap of TiO2 NTs was detected, whereby a synergistic antibacterial effect to Escherichia coli (E. coli) was observed through the coupling of TiO2 NTs photocatalysis and LSPR effect of Al NCAs (80 nm) in the UV-A range. The TiO2 NTs/Al NCAs hybrid surface showed excellent resistance against scratch. The results presented here may open a door for the further development of self-cleaning medical tools based on the decontamination strategies.

In this study, a new modified cyclic extrusion channel angular pressing (CECAP) process with multi-pass capability is presented for producing ultrafine-grained (UFG) Mg alloy. In this method, an additional extrusion stage with a low extrusion ratio is added at the end of the CECAP process to enhance hydrostatic stresses, equivalent strain, and facilitation of the process implementation. The experimental results showed a remarkable grain refinement with a relatively uniform distribution of microstructure and β-phase in the new CECAP processed sample. The average grain size decreased from ~75 µm in annealed condition to 4.5 µm and 3.5 µm in CECAP and new CECAP processes, respectively. Also, more dispersion of the β-phase with smaller sizes was observed in the processed microstructure. The hardness and its uniform distribution were increased significantly. The compressive yield stress (CYS) was enhanced to about 153.3 MPa from the initial value of ~85 MPa. Also, both the strength and ductility of the new CECAP processed sample were higher than those of CECAP processed one. These excellent properties might attribute to higher hydrostatic compressive stresses resulting from the last low ratio extrusion stage which was almost 50% higher in the new CECAP process.

Although silicon is the most used material in micro-electro-mechanical-systems, due to the excellent mechanical properties, it has poor performance for generating audible sound by capacitive micro-speakers. This paper studies the capability of dielectric elastomer material instead for generating the directional sound in the human hearing regime. Dielectric elastomers are a branch of smart materials with high desired and practical specifications such as large deformation, energy-efficient, lightweight, biocompatible, and fast response which share the common characteristics of changing their shape under an applied electrical voltage or charge. An elastic circular dielectric elastomer micro-plate with compliant electrodes on both sides suspended over the unmoving plate as a capacitive micro-structure has been modeled as a diaphragm of the micro-speaker. Then the Bessel panel array has been considered in a square matrix form composed of the number of dielectric elastomer micro-speakers. The nonlinear equation of the vibrations of a micro-speaker’s diaphragm under an electrostatic loading and equations of the sound pressure and sound radiation pattern have been presented and solved. The results have shown that utilizing dielectric elastomer-based micro-speakers in a Bessel panel array can generate a directional audible sound pressure in the human hearing range. In addition, the results clear that the desired sound waves in the human audible range and a private or personal listening zone can be produced through adopting an optimal value among the excitation frequencies, diaphragm numbers, radii and inter-element spaces of a Bessel panel array.

Design and simulation of an improved recycling folded cascode (RFC) operational transconductance amplifier (OTA) is presented. The new idea is based on minor changes in the conventional structure. Our improved amplifier is capable to enhance DC gain and unity gain bandwidth (UGBW) in the same −3dB frequency as for RFC structure. Moreover, fast-settling time, input-referred noise, total harmonic distortion (THD) and performances of power supply rejection ratio (PSRR) and common mode rejection ratio (CMRR) are also improved. Simulation results in 90 nm CMOS process indicate that the proposed amplifier has about 2 times the unity gain bandwidth (360 versus 175 MHz) and also has twice gain boosting (68.6 versus 62.5 dB) in the same −3 dB frequency and capacitor load of 10 pF @1.2 V power supply. The results also demonstrate a good figure of merit (FOM), and low sensitivity of temperature and power supply variations for the proposed amplifier.

Hydrostatic cyclic expansion extrusion (HCEE) process at elevated temperatures is proposed as a method for processing less deformable materials such as magnesium and for producing long ultrafine-grained rods. In the HCEE process at elevated temperatures, high-pressure molten linear low-density polyethylene (LLDPE) was used as a fluid to eliminate frictional forces. To study the capability of the process, AM60 magnesium rods were processed and the properties were investigated. The mechanical properties were found to improve significantly after the HCEE process. The yield and ultimate strengths increased from initial values of 138 and 221 MPa to 212 and 317 MPa, respectively. Moreover, the elongation was enhanced due to the refined grains and the existence of high hydrostatic pressure. Furthermore, the microhardness was increased from HV 55.0 to HV 72.5. The microstructural analysis revealed that ultrafine-grained structure could be produced by the HCEE process. Moreover, the size of the particles decreased, and these particles thoroughly scattered between the grains. Finite element analysis showed that the HCEE was independent of the length of the sample, which makes the process suitable for industrial applications.

Preparation of visible-light active photocatalysts for efficient degradation of pollutants from the industrial wastewater has received considerable attention in recent decades. The present study introduces a new sonochemical route for the preparation of graphene/TiO2/Ag nanocomposite for visible-light photocatalytic degradation of X6G (C.I. Reactive Yellow 2), a commonly used textile azo-dye. The obtained graphene/TiO2/Ag nanocomposite is extracted from the reaction solution by two drying methods: (1) conventional centrifuging and drying, and (2) freeze drying. Both of the dried samples are calcinated at 500 °C. The TEM images reveal that distribution of TiO2/Ag nanoparticles within the graphene sheets in the freeze dried nanocomposite is better than the conventional dried sample. Furthermore, the freeze dried nanocomposite has higher photocatalytic activity than the other nanocomposite. In conventional centrifuging and drying method, some of the TiO2/Ag nanoparticles are gradually pushed out from the graphene sheets during the drying process and graphene layers are stacked, therefore the dispersion effect of sonication is destroyed. However, in the freeze dried nanocomposite, because of the fast freezing of the sonicated sample by liquid N2, the TiO2/Ag nanoparticles are kept between the graphene sheets and calcination process attached and fixed them to the graphene, preserving the dispersion effect of sonication.

In the current work with innovative combination of sonochemical method with freeze-drying technique graphene/Pd-doped TiO2 nanocomposite was successfully synthesized which has high photocatalytic performance for degradation of Remazol navy blue a textile azo-dye under visible-light radiation. In the designed method, the ultrasound waves were used for dispersion of the Pd-doped TiO2 nanospheres between the graphene layers, which subsequent quick freezing of the obtained suspension by liquid N2 results in the fixing of the positions of the Pd-doped TiO2 nanospheres and the good dispersion of the graphene sheets in the nanocomposite. According to the obtained results, the freeze-dried sample has higher photocurrent, surface area and photocatalytic performance than the conventional dried one. All of these results are related to the best distribution of the graphene layers in the nanocomposite structure. Fast freezing of the graphene/nanoparticles suspension prevents from the stacking (due to the π-stacking interactions) and aggregation of graphene layers during drying, and results in the well distribution of graphene in the final nanocomposite.

We present a method for tuning the resonance frequency of a comb resonator using a combination of mechanically softening and hardening springs in order to achieve a high tuning range of resonant frequency. The nonlinear behavior of the structure is due to an angle in the main beam of a crab-leg flexure. Theoretical and simulation results are done to analyze the linear, quadratic, and cubic stiffness as well as frequency changes of the comb drive actuators. The frequency response of the resonator is achieved using the Lindstedt-Poincare perturbation technique. In order to validate the theoretical analysis, the results are compared with simulation results obtained by COMSOL software.

A nonlocal elasticity theory is a popular growing technique for mechanical analysis of the micro- and nanoscale structures which captures the small-size effects. In this paper, a comprehensive study was carried out to investigate the influence of the nonlocal parameter on the bifurcation behavior of a capacitive clamped-clamped nano-beam in the presence of the electrostatic and centrifugal forces. By using Eringen’s nonlocal elasticity theory, the nonlocal equation of the dynamic motion for a nano-beam has been derived using Euler–Bernoulli beam assumptions. The governing static equation of motion has been linearized using step by step linearization method; then, a Galerkin based reduced order model have been used to solve the linearized equation. In order to study the bifurcation behavior of the nano-beam, the static non-linear equation is changed to a one degree of freedom model using a one term Galerkin weighted residual method. So, by using a direct method, the equilibrium points of the system, including stable center points, unstable saddle points and singular points have been obtained. The stability of the fixed points has been investigated drawing motion trajectories in phase portraits and basins of attraction set and repulsion have been illustrated. The obtained results have been verified using the results of the prior studies for some cases and a good agreement has been observed. Moreover, the effects of the different values of the nonlocal parameter, angular velocity and van der Waals force on the fixed points have been studied using the phase portraits of the system for different initial conditions. Also, the influence of the nonlocal beam theory and centrifugal forces on the dynamic pull-in behavior have been investigated using time histories and phase portraits for different values of the nonlocal parameter.

Nitrate contaminated water resources, a huge environmental problem for countries, including our own. This research aims to evaluate the efficiency of the electrochemical process for the removal of nitrate from the aqueous solution by direct and alternating current. Experiments were done by the Taguchi method, including electrode array, time exposure, voltage, pH, and the initial concentration of nitrate. Minitab 17 and SPSS 18 software were utilized to design and data analysis. In detail, the connection of the electrodes was monopolar, and the direct current (DC) has a greater efficiency as alternating current (AC) in the nitrate removal (p 0.001). In AC, the nitrate initial concentration, voltage, electrodes material, contact time, and pH have the most effect on the nitrate removal. The optimized conditions for nitrate removal include Al-Al electrode, pH of 7, a voltage of 30 V, and nitrate initial concentration of 100 mg/L with the contact of time 150 min. Selection of appropriate materials for electrodes construction, adequate voltage, and removal of intervention agents from aqueous solution led to greater removal efficiencies. The optimized conditions that can reduce the aqueous solution ORP with high speed and the electrochemical reactor efficiency for nitrate removal were increased. PRACTITIONER POINTS: Electrochemichal (EC) process is evaluated for treatment of nitrate wastewater for the first time. High removal efficiency (over 95%) from nitrate wastewater was obtained. Minimizing energy consumption and maximizing nitrate removal were simultaneously achieved in the integrated single EC process.

Laser-induced thermal therapy, due to its applications in various clinical treatments, has become an efficient alternative, especially for skin ablation. In this work, the two-dimensional thermomechanical response of skin tissue subjected to different types of thermal loading is investigated. Considering the thermoelastic coupling term, the two-dimensional differential equation of heat conduction in the skin tissue based on the Cattaneo–Vernotte heat conduction law is presented. The two-dimensional differential equation of the tissue displacement coupled with the two-dimensional hyperbolic heat conduction equation in the tissue is solved simultaneously to analyze the thermal and mechanical response of the skin tissue. The existence of mixed complicated boundary conditions makes the problem so complex and intricate. The Galerkin-based reduced-order model has been utilized to solve the two-sided coupled differential equations of vibration and heat transfer in the tissue with accompanying complicated boundary conditions. The effect of various types of heating sources such as thermal shock, single and repetitive pulses, repeating sequence stairs, ramp-type, and harmonic-type heating, on the thermomechanical response of the tissue is investigated. The temperature distribution in the tissue along depth and radial direction is also presented. The transient temperature and displacement response of tissue considering different relaxation times are studied, and the results are discussed in detail.

The moiré engineering of two-dimensional magnets opens unprecedented opportunities to design novel magnetic states via the stacking-dependent magnetism. Here, we explore the formation and control of ground state topological spin structures (TSTs) in moiré CrI3 without including the nearest-neighbor (NN) Dzyaloshinskii-Moriya interactions (DMI) and dipolar interactions in the theoretical approach. Using stochastic Landau-Lifshitz-Gilbert simulations, we unveil the emergence of vortex and antivortex interlayer exchange fields at large moiré periodicity. The whirling fields stabilize spontaneous and field-assisted ground state TSTs with various topologies, including skyrmionic clusters with high topological charges. Furthermore, by examining the effect of the Kitaev interaction and the next NN DMI, we propose the latter as the unique spin-orbit coupling mechanism compatible with the experimental results on monolayer and twisted CrI3. Therefore, our study goes beyond the current knowledge about TSTs in moiré magnets, opens exciting opportunities for moiré skyrmionics, and uncovers the spin-orbit coupling in CrI3.

Accumulative roll bonding (ARB) is a new and cost-effective process for the production of ultrafine-grained sheets by applying severe plastic deformation. Various mechanical properties of sheets improve after ARB process. However, the material formability severely decreases in the ARBed sheets restricting their usage in industrial applications. The main objective of this study is to investigate the effect of the high strain rates on the formability improvement of ultrafine-grained sheets manufactured by the ARB process. For this purpose, the electromagnetic forming (EMF) has been performed for applying high strain rates on ARBed pure copper sheets and its capability to resolve the low toughness issue of the ultrafine-grained products of the ARB process has been investigated. In the first step, several sheet samples have been subjected to one, two, and three ARB passes, and their mechanical properties such as microhardness, mechanical strength, and formability have been determined after each pass. The results have indicated a substantial increase in the sheets hardness and mechanical strength and a significant decrease in their formability especially after the first pass. Afterwards, the Nakazima test and the EMF have been used to form the ARBed sheet samples in the quasi-static and high strain rate conditions and then the forming limit diagram and formability of formed samples have been compared in these conditions. It has been found that the formability of the one-, two-, and three-pass ARBed sheets in plane strain conditions have been, respectively, increased 102%, 113%, and 99% in the high strain rate with respect to the quasi-static condition.

Laser-induced thermal therapy, due to its applications in various clinical treatments, has become an efficient alternative, especially for skin ablation. In this work, the two-dimensional thermomechanical response of skin tissue subjected to different types of thermal loading is investigated. Considering the thermoelastic coupling term, the two-dimensional differential equation of heat conduction in the skin tissue based on the Cattaneo–Vernotte heat conduction law is presented. The two-dimensional differential equation of the tissue displacement coupled with the two-dimensional hyperbolic heat conduction equation of tissue is solved simultaneously to analyze the thermal and mechanical response of the skin tissue. The existence of mixed complicated boundary conditions makes the problem so complex and intricate. The Galerkin-based reduced-order model has been utilized to solve the two-sided coupled differential equations of skin displacement and heat transfer with accompanying complicated boundary conditions. The effect of various types of heating sources such as thermal shock, single and repetitive pulses, repeating sequence stairs, ramp-type, and harmonic-type heating, on the thermomechanical response of the tissue is investigated. The temperature distribution in the tissue along the depth and radial direction is also presented. The transient temperature and displacement response of tissue considering different relaxation times are studied, and the results are discussed in detail.

In the present paper, a new method for producing ultrafine grained microtubes of AZ31 magnesium alloy is proposed. The method consists of performing isothermal hot micro-backward extrusion on severe plastic deformation processed samples. One-pass equal channel angular pressing (ECAP) and cyclic extrusion compression angular pressing forward extrusion (CECAP-FE) were performed on an as-cast coarse-grained Mg-3Al-1Zn magnesium alloy before microtube fabrication. Microstructure and microhardness of the samples before and after micro-backward extrusion and deformation force during the fabrication process were studied. As a result, it was revealed that the proposed method performed on CECAP-FEed precursors could effectively produce ultrafine grained AZ31 magnesium alloy microtubes with excellent microhardness, good uniformity in shape, microstructure, and microhardness.

A novel one-pass integrated severe plastic deformation method, entitled extrusion compression angular pressing forward extrusion (ECAP-FE), was designed and used for fabricating a fine-grained as-c...

Permanent implants are going to be replaced by the implementation of biodegradable magnesium-based implants in fixation of internal bone fractures because of many concerns associated with conventional implants. However, biodegradable magnesium-based biomaterials exhibit higher biodegradation rate and low mechanical properties which are the main challenges. This work aims to almost overcome both disadvantageous by grain refining of a WE43 magnesium alloy containing 93.04 wt% Mg, 4.12 wt% Y, 2.15 wt% Nd, 0.43 wt% Zr, and 0.26 wt% La. In this study, the consequences of combined severe plastic deformation (SPD) on the mechanical properties, microstructure, and in vivo degradation behavior of WE43 magnesium alloy were investigated. To do so, WE43 magnesium alloy was chosen and processed through multi-pass equal channel angular pressing (ECAP) at 330 °C for up to four passes followed by an extrusion process. The results showed that higher strength and hardness with minimum ductility less was obtained in the sample processed via two-pass ECAP followed by extrusion. In vivo biodegradation experiments showed higher degradation rate for the unprocessed coarse-grained (CG) WE43 sample. The two-pass ECAP and extruded sample with ultrafine-grained (UFG) structure exhibited the lowest in vivo biodegradation rate besides appropriate mechanical properties. It may be concluded that the WE43 magnesium alloy processed via two-pass ECAP and extrusion could be a very promising candidate for biodegradable implants from both mechanical and biocorrosion viewpoints.

Ultrafine grained ZK60 magnesium (UFG–ZK60 Mg) tubes were successfully fabricated by a parallel tubular-channel angular pressing (PTCAP) process. The number of pass effects on the phase composition, microstructural features and mechanical properties were examined. Also, two types of Artificial Neural Network known as Radial Basis Function (RBF) and Multi-Layer Perceptron (MLP) were employed to accurately estimate mechanical behavior of the PTCAP-processed ZK60 Mg alloy. The results showed that all the processed tubes had more refined microstructure with ~ 7 to 0.9 μm grain sizes, which consist of an average crystallite size between 68 ± 8 and 51 ± 8 nm, compared to the as-received specimen with a mean grain size of ~ 90 μm. Similar XRD profiles were achieved following different PTCAP passes, however, some discrepancies were observed as the number of passes increased, which corroborated the structural changes during the PTCAP process. The microscopic observations also revealed the microstructural changes by increasing the PTCAP passes. The hardness of the processed tubes increased with the number of PTCAP passes, from 77 ± 2 HV for the unprocessed alloy to a maximum of 111 ± 2 HV at three PTCAP passes. The PTCAP process increased not only mechanical strength but also the ductility of the processed tubes, where the highest yield strength (σYS = 320 MPa), ultimate tensile strength (σUTS = 397 MPa) and elongation to failure (δ = 14%) values were obtained at the second pass of PTCAP. However, with increasing number of PTCAP passes to three, δ reached 4% and σYS and σUTS decreased by 31% and 11%, respectively. Findings from the neural based-predictive models indicated that both RBF and MLP can be employed for accurately estimating the mechanical properties of the PTCAP-processed ZK60 Mg alloy.

The cellular response on the surface of equal-channel angular pressing (ECAP)-processed nanostructured titanium grade 2 substrates after plasma electrolytic oxidation (PEO) has been investigated. The results demonstrate that, after four passes of the ECAP process, the mechanical properties of the nanostructured sample were significantly enhanced compared with the coarse-grained sample. The results of x-ray diffractometry and energy-dispersive x-ray spectroscopy (EDS) showed that hydroxyapatite particles formed on the nanostructured Ti surface modified by PEO, indicating enhanced bioactivity. The growth rate and degree of cell attachment were notably increased, while the number of necrotic and apoptotic cells was negligible on the surface of the PEO-coated nanostructured titanium. This enhanced cell activity is related to the ultrafine grains with a distinct surface oxide layer having specific morphology and composition. As both the surface and bulk properties of the PEO-processed nanostructured titanium samples were improved, these samples could be excellent candidates for use as bone substitute materials.

Background: Escherichia coli (E. coli) bacteria is one of the hazardous human pathogens. Consequently, developing the rapid and effective method for identification and quantization of E. coli is popular in biotechnological researches in recent years. Experimental: In this research, a label-free capacitance E. coli biosensor was fabricated based on immobilizing bacteriophage on the carbon paste electrode (Cp). Reduced graphene (RGr) was synthesized and used as a substrate for immobilization of bacteriophage on the Cp surface. E. coli bacteriophage was trapped in graphene modified carbon paste electrodes. The immobilization accuracy was confirmed via electrochemical techniques. The modified electrodes were applied as indicator electrodes for capacitance measurements of E. coli. Results: Through this method, E. coli was detected in a concentration range of 33×10-3 to 330×10-3 N L-1 (number of E. coli per Liter) with a correlation coefficient of 0.99 and a detection limit of 12×10-3 N L-1. Conclusion: The proposed biosensor has a fast response time of about 5 s and good selectivity over other bacteria.

In this paper, a new approach using a novel severe plastic deformation route is presented for consolidation and processing of a high-density and ultrafine-grained pure magnesium. Pure magnesium particles were successfully consolidated at 400 °C into a sufficiently dense bulk material using a new combined method including cyclic extrusion compression, equal channel angular pressing (ECAP) and conventional extrusion. The grain refinement, consolidation behavior and mechanical properties were deeply investigated. Results showed that the as-consolidated material had a fine grain structure with excellent tensile strength and ductility compared to as-cast and as-ECAPed specimens. Vickers microhardness increased from 38.75 to 52.58 during the process. Porosity also reduced considerably from 12.55 to 1.2% during the process which led to a dense bulk material. Results indicate that the introduced method is a promising and effective process for producing strong bulk materials from metal powders.

One of the most important shortcomings of the polymeric membranes in comparison with inorganic membranes is the trade-off between permeability and selectivity. Gas permeability in inorganic membranes follows different mechanisms including capillary condensation mechanism. The aim of present study was improving the polymeric membranes performance by introducing capillary condensation mechanism for the gas transport similar to that observed in the inorganic membranes. Capillary condensation of gases needs a continuous diffusion pathway, therefore in the present study short glass wool fibers (with a micro size in diameter and millimeter size in length) were chosen as a proper alternative instead of nanoparticles. Short glass wool fibers present proper dispersion in the Pebax matrix as a result of its good compatibility with polymer segments. Gas permeability behavior in such composite membranes was assisted using pure CO2, CH4 and N2 gases. Obtained results demonstrated that gas permeability behavior in the short fiber reinforced composite membranes is depends on the fiber content. At lower content of the fiber, such reinforcement causes simultaneous increment in gas permeabilities in a way that 62.37%, 32.12% and 50.71% increase in permeability was observed for CO2, CH4, and N2 respectively. But at higher content due to formation of more continuous interface, capillary condensation was appeared for more condensable gas (CO2) which results in 17.65% reduction in its permeability. Based on the results the using of short fiber instead of nanoparticles in polymeric membranes can be more beneficial in performance and economic point of view.

Enhancement of both efficiency and reliability of MEMS structures has always been an interesting and even essential issue for research community. This paper provides a comparative investigation in this field focusing on the role of initially curved electrodes of capacitive micro-switches. Four models have been introduced by appliance of curved microbeams as either upper or lower electrodes of a capacitive MEMS switch, as well as the conventional base model with straight both electrodes. By introducing a mathematical model and appropriate numerical procedure, the contact area between two electrodes, which has direct effect on the reliability has been estimated using Hertz relation for all models. The electromechanical coupling factor which is related to the efficiency of the switch has been calculated considering the stored mechanical and electrical energy of the system. The results have shown that by appliance of an initial curvature to the both electrodes, the estimated contact area can increase up to 279% compared to the conventional switches. Also, a switch with straight moveable electrode and curved substrate exhibits an increase in coupling factor up to 24% compared to the base model, while increasing the pull-in voltage of the switch.

The rapid expansion of supercritical solution (RESS) process is a novel method to produce free-solvent particles with narrow particle size distribution (PSD), and it is offered to replace conventional particle formation methods. The present study is aimed to investigate the numerical simulation of the RESS process comprising hydrodynamic and particle formation and solving population balance equation to compute PSD of solute-supercritical CO2 (SC-CO2) systems. Mass, momentum and energy balances in addition to an accurate equation of state are used to calculate hydrodynamic behavior of SC-CO2 at various conditions through a nozzle and supersonic free jet with considering heat exchange in the nozzle. The solubility of TBTPP (5, 10, 15, 20-tetrakis (3, 5-bis (trifluoromethyl) phenyl) porphyrin) in SC-CO2 is calculated using the Soave–Redlich–Kwong equation of state with van der Waals mixing rule. After that, supersaturation and nucleation of TBTPP and three other drugs, i.e., aspirin, salicylic acid and ibuprofen, are investigated. Eventually, the method of moments is used to solve the population balance equations to determine PSD of the solutes. The results are presented with and without coagulation. Furthermore, the effect of nozzle length and pre-expansion temperature on PSD is studied. Furthermore, to improve the results of coagulation model on PSD, collision frequency and lognormal function are modified. The modifications improve the coagulation results. The average absolute percent deviation of TBTPP solubility is 1.86. The CO2 hydrodynamic behavior shows the same trend as reported in the literature. Moreover, results of PSD calculation with coagulation indicated there is a good agreement with the experimental ones.

Magnesium and its alloys have attracted a great deal of attention in the field of biomedical applications, especially biodegradable stents. However, they have not been extensively used because of some inherent limitations such as poor mechanical properties and high corrosion rate. During the last decade, the selected fabrication methods for producing stent precursors is of great importance and can significantly affect the final stent’s properties. In this paper, the progress of fabrication methods and properties of Mg microtubes for using as biodegradable stents are reviewed. The paper will firstly classify the fabrication methods, and then investigate produced microtubes’ properties from the perspective of mechanical, microstructural and biocorrosion properties.

In the current study, hydrostatic tube cyclic expansion extrusion (HTCEE) was proposed as a new severe plastic deformation (SPD) method for producing relatively long and large ultrafine-grained (UFG) tubes. In this process, a moving mandrel placed inside the hollow tube sample and also using high fluid pressure are the cores of this technology. To investigate the applicability of the process, commercially pure copper tube was processed and mechanical properties and microstructure were examined. It was shown that the grain size was reduced to below 150 nm after the only a single pass of HTCEE from the initial value of 65 μm. The results demonstrated that both yield and ultimate strengths were increased to 270 MPa and 345 MPa after one pass of HTCEE from the initial value of 75 MPa and 207 MPa respectively while the elongation was reduced to 41% from 55%. It is realized that the remarkable increase in the strength is obtained with a very low ductility loss. Microhardness was also enhanced to about 133 Hv from the initial value of 59 HV after HTCEE process while exhibiting excellent hardness homogeneity. Reducing the total load, increasing the processable tube length and interestingly achieving simultaneous strength and ductility are important advantages of HTCEE. This method seems to be very interesting and very promising for the future industrial application.

In this study, severe plastic deformation (SPD) process of hydrostatic tube cyclic extrusion–compression (HTCEC) was performed through two passes on the commercially pure copper tubes with the purpose of fabricating relatively long ultrafine-grained (UFG) tubes. In HTCEC process, the presence of pressurized hydraulic fluid around the piece plays a key role in the reduction of the friction load and, consequently, in the reduction of required pressing load. In principle, this facilitates the production of long and large tubes. After processing by HTCEC, the mechanical characteristics and microstructure evolution were examined. Microstructure analysis revealed that after the first pass of HTCEC process, an ultrafine cell microstructure with an average size of ~ 993 nm was attained. After two passes of HTCEC, the average size of cells/subgrains was reduced to ~ 340 nm. This was while the average grain size of the annealed sample was 41 μm. Also, after two passes of HTCEC process, a remarkable increase in the yield strength from 154 to 336 MPa, and the ultimate strength from 223 to 414 MPa was observed. Furthermore, the mean value of microhardness increased from 74 to 149 HV, and a more uniform distribution of microhardness along the thickness was seen, compared to the first pass of HTCEC. Meanwhile, unlike most conventional SPD methods, the value of elongation to failure was slightly lessened from 59.5 to 41.6%. SEM fractography analysis denoted that mostly ductile fracture occurred in the HTCEC-processed samples. In general, two main advantages of HTCEC process can be the production of relatively long ultrafine-grained tubes and the significant increase in the strength and hardness besides a low loss of ductility.

The variability of the electrical characteristics of current-mirror circuits based on organic thin-film transistors is analyzed using experimental data obtained from a large number of discrete transistors and from a large number of current mirrors fabricated on a flexible polymeric substrate. Depending on the channel length of the transistors (5 μm or 2 μm) and on whether the two transistors comprising the current mirror are biased simultaneously or separately, the drain-current mismatch of the current mirrors is as small as 1% and as large as 25%.

We present analytical physics-based compact models for the Schottky barriers at the interfaces between the organic semiconductor and the source and drain contacts in organic thin-film transistors (TFTs) fabricated in the coplanar and the staggered device architecture, and we illustrate the effect of these Schottky barriers on the current-voltage characteristics of the TFTs. The model for the source barrier explicitly takes into account the field-dependent barrier lowering due to image charges. Potential solutions have been derived by applying the Schwarz-Christoffel transformation, leading to expressions for the electric field at the source barrier and for the contact resistance at the source contact. With regard to the drain barrier, a generic compact-modeling scheme based on the current-voltage characteristics of a barrier-less TFT is introduced that can be applied to any compact dc model. Finally, both models are incorporated into an existing charge-based compact dc model and verified against the results of measurements performed on coplanar and staggered organic TFTs with channel lengths ranging from 0.5 μm to 10.5 μm.