Saturation Operation Research Articles

Fabrication, compact & device modeling of 4H–21DNTT organic thin film transistor

Abstract In this study, we explored a novel organic semiconductor (OSC), 6,6 bis-(trans4-butylcyclohexyl) dinaphtho[2,1-b:2,1-f]thieno[3,2-b]thiophene (4H–21DNTT). The work also includes a TCAD device model for optimizing and improving the device performance. Both the experimental and simulated results have demonstrated sufficient mobility to realize complex circuits. To validate its potential, a compact model was developed and employed in the SPICE simulator for complex-circuit simulations. Both models accurately capture the below-threshold, linear, and saturation operating conditions through a unified approach, removing the necessity for explicitly defining the threshold and saturation voltages.

Microstructural, dielectric, electrical, electromagnetic, and magnetic property enhancements in GdIG /TrIG/ Mn0.2Co0.3Zn0.5Fe2O4 ferrites composites for electronic devices application

Gadolinium garnet ferrite (GdIG) and terbium garnet ferrite (TrIG), known for their favourable magnetic and dielectric characteristics, were combined with doped zinc spinel ferrite (GdIG)x-(TrIG)y/Mn0.2Co0.3Zn0.5Fe2O4(1-x-y) (at x=1 y=0, x=0 y=1, x=y=0.5, x=y=0.25, x=y=0) to achieve improved permittivity, permeability and magnetic properties with reduced magneto-dielectric losses. Our study details the synthesis process and the resulting enhancements in structural, magnetic, and dielectric properties of the prepared samples. Analysis of the X-ray diffraction (XRD) patterns confirmed the presence of a crystalline structure characterized by both cubic spinel and cubic garnet phases in the composites. The microstructures of the composites were analysed with field emission scanning electron microscopy (FESEM), revealing the variation in a grain size from 0.11 μm to 0.96 μm at x =y=0.5. A thorough link between the crystal structure and XRD spectra, transmission electron microscope (TEM), and selected area electron diffraction (SAED) patterns have all been investigated in order to enhance the characterisation of the samples. At 1KHz, the composites exhibit highest electrical resistivity values of 5.9×106 Ωm and 2.6×106 Ωm. With the incorporation of spinel ferrites in garnet ferrite composite (x=y=0.25) the highest value of dielectric constant (885.2) and low value of dielectric loss (0.07) at 100 KHz has been obtained. Permeability values, derived from permittivity data, showed an increase in real permeability values of from 1.4×1012 to 9.2×1017 for x=y=0.5 to x=y=0.25 composite. Vibrating sample magnetometer (VSM) further confirm that the composite x=y=0.25 has highest magnetic saturation (148.8 emu/g), coercivity (502 Oe) and microwave operating frequency (33.6 GHz). The observed high dielectric constant, low loss values, switching field distribution and good magnetic properties suggest the potential suitability of these samples for various electronic devices like: high frequency devices, antennas, switching devices and magnetic recording devices.

Improved Temperature-Scalable DC model for SiC power MOSFET including Quasi-Saturation effect

In this paper, accurate temperature-dependent static model for Silicon-Carbide (SiC) power MOSFET is presented. The proposed model is formed by two equations relating to linear and saturation operating regions. In this model, new formalism of the saturation drain current is introduced to consider the peculiar features observed in the I-V static characteristics of the SiC power MOSFET: a) moderate inversion region, or region of low gate voltages and b) quasi-saturation region, region of high gate voltages at which the drain current becomes less sensitive to the increase of gate voltage. In addition, the model captures with high-precision the transition region between linear and saturation region, pinch-off region, noticed in the output characteristics of the SiC power MOSFETs. It will be shown that the model equations ensure continuity and smooth transition between all operating regions. Temperature scaling of the model is carried out by its temperature scaling parameters. The proposed compact model is simple and efficient using reduced number of technology independent parameters. Simple parameter extraction procedure is described that uses an optimizer algorithm based on good experimental initial guess. Excellent agreement is obtained by comparing model to TCAD simulation and device measurement.

Geometrical parameters optimization to improve the effective thermal conductivity of the gas diffusion layer for PEM fuel cell

The main concern of this article is a numerical investigation of the geometrical parameters of composite gas diffusion layers (CGDLs) and their impact on effective thermal conductivity (ETC). The geometric parameters under investigation include porosity, thicknesses of the gas diffusion layer (GDL) and micro porous layer (MPL), as well as fibers diameter and orientation. Additionally, non-geometric parameters such as saturation level and operating temperature are examined. This study utilizes realistic full microstructure simulations (GDL + MPL + PolyTetraFluoroEthylene/PTFE + binder) of a paper GDL type (SGL 25BC) to examine and enhance ETC in both in-plane (IP) and through-plane (TP) directions by optimizing the parameters under investigation. To achieve this, a MATLAB code was used to generate microstructures under various conditions, which were simultaneously imported into COMSOL multi-physics via live link technique (LLT). Subsequently, the non-dominated sorting genetic algorithm II (NSGAII) was employed as an optimization method to refine the geometric/non-geometric parameters. Finally, the ETC results for both TP and IP directions were compared with experimental data from the literature. The optimized microstructure exhibits higher ETC values compared to both the initial simulated microstructure and the experimental data. This finding indicates that fabricating CGDLs within the recommended range of optimal geometric values can lead to a substantial increase in their ETC.

Quantitative Analysis of Influencing Factors on Changzhou Ship Lock Capacity

The Changzhou ship lock is approaching its capacity limit. In order to quantitatively analyze the influencing factors that restrict the capacity of the Changzhou ship lock, this study proposes an influencing factor analysis method based on principal component analysis (PCA). This method estimates the confidence interval of ship passing time by fitting a lognormal distribution curve, eliminates redundancy in navigability data by combining the hydrological data and cargo load data, and quantitatively analyzes the influencing factors of ship lock capacity under saturated operating conditions. The results show that the influencing factors of Changzhou ship lock capacity are classified according to their influence contribution rate as minimum water depth above the lock sill, operation direction, ship dimensions, draft, loading capacity, and actual load. The research results can provide a theoretical basis for improving the ship lock capacity and have application value for lock scheduling management.

A COMBINED ACTIVE (PIEZOS) AND PASSIVE (MICROSTRUCTURING) PARTIAL FLOW-BOILING APPROACH FOR STABLE HIGH HEAT-FLUX COOLING WITH DIELECTRIC FLUIDS

Controlled but explosive growth in vaporization rates is made feasible by ultrasonic acoustothermal heating of the microlayers associated with microscale nucleating bubbles within the microstructured boiling surface/region of a millimeter-scale heat exchanger (HX). The HX is 5 cm long and has a 1 cm × 5 mm rectangular cross section that uses saturated partial flow-boiling operations of HFE-7000. Experiments use layers of woven copper mesh to form a microstructured boiling surface/region and its nano/microscale amplitude ultrasonic (~1-6 MHz) and sonic (< 2 kHz, typically) vibrations induced by a pair of very thin ultrasonic piezoelectric-transducers (termed piezos) that are placed and actuated from outside the heat-sink. The ultrasonic frequencies are for substructural microvibrations whereas the lower sonic frequencies are for suitable resonant structural microvibrations that assist in bubble removal and liquid filling processes. The flow and the piezos' actuation control allow an approximately 5-fold increase in heat transfer coefficient value, going from about 9000 W/m<sup>2</sup>-°C associated with microstructured no-piezos cases to 50,000 W/ m<sup>2</sup>-°C at a representative heat flux of about 25 W/cm<sup>2</sup>. The partial boiling approach is enabled by one inlet and two exit ports. Further, significant increases to current critical heat flux values (~70 W/cm<sup>2</sup>) are possible and are being reported elsewhere. The electrical energy consumed (in W) for generating nano/micrometer amplitude vibrations is a small percentage (currently < 3%, eventually < 1% by design) of the total heat removed (in W), which is a heat removal rate of 125 W for the case reported here.

Anti-windup modified proportional integral derivative controller for a rotary switched reluctance actuator

Over the last decade, industrial applications and promising research domains including robotics and automotive engineering have adopted the rotary switched reluctance actuator (SRA). SRA's fault tolerance, simple, strong structure, and high-frequency operation make it popular. However, the SRA's nonlinear magnetic flux flow and saturation operation negate its benefits. Several control systems have been developed; however, they often need extensive mechanism models and advanced control theory, making them impracticable. This paper proposes a modified proportional integral derivative (PID) controller to evaluate the control performance, which comprises of PID controller with an anti-windup, a linearizer unit, and switching mechanism to activate the SRA phases. The linearizer unit aids to compensate for the nonlinear current-displacement relationship. The anti-windup element helps to halt the integral action during the starting motion. At the fully aligned position, 60°, the modified PID reduced positioning steady-state error by 4.3 times at 76.9%, overshoot by 48.8%, and settling time by 25.3%. Both the modified PID and conventional PID showed zero steady-state error at intermediate position, 70°, however the modified PID controller depicted an improved percentage overshoot by 54.5% and settling time by 74.5%. The results show that the modified PID outperforms conventional PID in transient response, steady-state error, overshoot, and settling time.

Parameter Identification of Switched Reluctance Motor SRM Using Exponential Swept-Sine Signal

Switched reluctance motors (SRMs) received major interest in several domains, e.g., in electric vehicles. This interest is due to the many advantages of SRMs, including operation at a wide range of speeds, high performances, low cost, robustness to run under degraded conditions, and controllability. One of the major aspects in the design and implementation of controllers for SRMs is the estimation of the motor parameters. An accurate estimate of these parameters is a challenge due to the highly nonlinear behavior of SRMs in addition to their magnetic saturated operating mode to maximize the energy transfer. This paper aims at estimating the parameters of SRM by developing a new SRM model using an analytical technique. The proposed technique is based on a parallel connection of several Hammerstein models that have polynomial nonlinearity. The model is driven by a swept-sine signal, and then finite element method analysis is performed to estimate the SRM parameters. The effectiveness of the proposed method is highlighted by numerical simulation. All these simulations were performed using MATLAB/SIMULINK.

Internal Characteristics of Air-Supplied Plasma Synthetic Jet Actuator

Conventional plasma synthetic jet actuators rely only on jet orifice for suction when functioning for long durations. A limited supplementary gas leads to jet velocity reduction and weakening of the flow control ability. Therefore, this study proposes an air-supplied actuator with a check valve externally connected to the cavity to improve its gas-supplying ability and jet performance. A quartz glass discharge chamber is developed to clarify the internal working mechanism of the air-supplied actuator. High-speed schlieren is employed to photograph the internal flow field of the discharge chamber. The results reveal that the inhalation airflow velocity of the jet orifice is doubled when the actuator is continuously working in the effective frequency band under the combined action of additional air supply from the check valve in the inhalation recovery stage. The gas pressure in the cavity is closer to the initial discharge state, discharge breakdown voltage is higher, discharge energy is stronger, and the process of gas expansion to generate a jet is less affected by the core defect of the heat source, thereby significantly increasing the jet velocity and saturation operating frequency of the actuator. The obtained results have important implications for the performance optimization of the air-supplied actuator.

ERGONOMIC STUDIES OF THE PROCESS OF ARTIFICIAL INSEMINATION OF PIGS

Goal. To research the comparison of artificial insemination processes in a number of pig farms based on the developed theoretical principles of ergonomic assessment. Methods. Experimental research was carried out at “Agrofirma “Khlibne ” LLC, FG “Shubske ”, SE EE “Hontarivka” of Institute of Animal Science NAAS, and FOP “Syvoplias” of Kharkiv region based on traditional approaches. As a basis for dividing the process of artificial insemination of pigs into technological operations, the farm of FG "Shubske" was taken, as such, where the process of artificial insemination of pigs is the most saturated with technological operations. According to the determined technological operations of the process of artificial insemination of sows, more generalized characteristics of the labor process, the number, sequence and duration of individual component movements were determined, with the classification of labor movements by determination, severity, naturalness, purpose, direction and reach in accordance with the methods, based on the basic systems of trace elements time standards, normative documents and recommendations. The indexes obtained experimentally were worked out by the method of variational statistics, using MS Excel software. The results. The process of artificial insemination in different farms has certain differences. The process of artificial insemination from a number of evaluated farms is the most saturated with technological operations in the breeding farm of FG "Shubske". Regarding different farms, there are differences in the use of stimulating devices, the load on the operator and the way of housing sows during insemination. According to the evaluated farms, the test boar is used twice a day in FG “Shubske ”, once in the morning in the SE EE “Hontarivka” of Institute of Animal Science NAAS, in FOP “Syvoplias V.V.” the detection of sows in estrus occurs without the involvement of a test boar. Also, the anthropometric, physiological and individual characteristics of the artificial insemination operator were evaluated for two operators for each of the evaluated farms. Weight indexes between operators in different farms differed more significantly (р<0.05). At the same time, no discrepancies were found in terms of arm length. Regarding disagreements between operators within individual farms, the greatest consolidation in terms of height and live weight was found in FOP "Syvoplias V. V.". The largest discrepancies in the length of the hands of the operators were found in SE “Hontarivka” of Institute of Animal Science NAAS. In the vast majority of cases, unconsolidated values were obtained for pulse and blood pressure indexes. Conclusions. On the basis of ergonomic studies of the process of artificial insemination of pigs in the conditions of three different farms, the differences have been determined, which indicate the need to adjust individual technological approaches and carry out the conversion of premises for artificial insemination of pigs in order to further increase the efficiency of the work of technicians and the procedure of artificial insemination as a whole in the SE EE "Hontarivka" » of Institute of Animal Science NAAS and in FOP "Syvoplias V. V.". Key words: sow, artificial insemination, ergonomics, machine, reproduction, sperm production.

Robust Stability Criterion for State-Delayed Discrete-Time Systems Combined with a Saturation Operator on the State-Space

Robust Stability Criterion for State-Delayed Discrete-Time Systems Combined with a Saturation Operator on the State-Space

Indian Monument Recognition Using Deep Learning

Monuments are physical structures built or created dedicated to a person or event. Their importance to the region they belong to makes their documentation and preservation important. Monuments being 3D objects, pose is an issue in terms of the difference in perception of the monument images. There can be an immense variation because of the viewpoint from which the image is being taken. To overcome this issue, Data Augmentation is used in this study. Random Flip, Random Rotation, Random Translation and Random Zoom, Random Contrast, Random Hue, Random Brightness, and Random Saturation operations under Data Augmentation are applied on the dataset. This research uses Deep Learning architectures on a hybrid dataset of “Indian Monument Recognition Dataset” and “Qutub Complex Monuments' Images Dataset.” InceptionV3, MobileNet, ResNet50, AlexNet, and VGG16 recognize the monuments with an accuracy of 97.79%, 93.73%, 86.47%, 68.88%, and 61.33% respectively.

Upgrading of IOT Big Data Governance Scheme in Microenterprise Governance

The accelerated development of the tertiary industry is the inevitable result of productivity improvement and social progress. Vigorously developing the tertiary industry is conducive to enhancing the stamina of agricultural production, promoting the socialization and professionalization of industrial and agricultural production, optimizing the production structure, promoting the full development of the market, and alleviating employment pressure so as to promote the sustained, rapid, and healthy development of the entire economy. Microenterprises are one of the carriers for the development of the tertiary industry. Microenterprises can effectively alleviate the country’s increasingly serious employment problems. However, with the saturated operation of microenterprises, the competition of microenterprises is becoming more and more intense. Small- and medium-sized enterprises are under the pressure of competition in terms of manpower, location, consumption level, and supply of goods. At the same time, small- and medium-sized enterprises are also facing problems such as high operating pressure, rising costs, financing difficulties, and heavy taxes and fees. In this environment, if small enterprises want to maintain long-term development, they must adapt to new forms and take active measures. Small- and medium-sized enterprises must use flexible and diverse forms of employment, actively adjust the industrial structure, vigorously develop the tertiary industry, and absorb more employed labor. The purpose of this paper is to study the use of IOT big data to optimize and upgrade the governance scheme of microenterprises. The purpose is to improve the governance effect of microenterprises and promote the development of microenterprises. This paper proposes optimal governance based on the collaborative algorithm and Pareto algorithm and conducts governance evaluation in multiple aspects of microenterprises, respectively. After obtaining the relationship with profit maximization, this paper finally analyzes and summarizes, obtains two optimal schemes, and evaluates and compares these two schemes with the traditional scheme. The results show that the profit maximization degree of the two schemes can reach 92%. Compared with the traditional scheme, the maximum profit of small enterprises after the implementation of governance has increased by about 30%.

Analysis of methods and approaches of the electromagnetic calculation of induction machines regarding their use to solve multiphysical problems

PurposeFor the electromagnetic simulation of electrical machines, models with different ranges of values, levels of detail and accuracies are used. In this paper, numerical and two analytical models of an induction machine (IM) are analysed with respect to these aspects. The purpose of the paper is to use these analyses to discuss the suitability of the models for the simulation of various physical quantities of an IM.Design/methodology/approachAn exemplary IM is simulated using the two-dimensional numerical finite element method, an analytical harmonic wave model (HWM) and an extended HWM. The simulation results are analyzed among themselves in terms of their level of detail and accuracy. Furthermore, the results of operating map simulations are compared with measured operating maps of the exemplary machine, and the accuracy of the simulation approaches is discussed in the context of measurement deviations and uncertainties.FindingsThe difference in the accuracy of the machine models depends on the physical quantity of interest. Therefore, the choice of the simulation method depends on the nature of the problem and the expected range of results. For modeling global machine quantities, such as mean torque or losses, analytical methods such as the HWM s are sufficient in many applications because the simulation results are within the range of measurement accuracy of current measurement systems. Analytical methods are also suitable for local flux density curves under certain conditions. However, for the simulation of the influence of local physical effects on the machine behavior and of temporally highly resolved quantities in saturated operating points, the accuracy of the analytical models decreases and the use of the finite element method becomes necessary.Originality/valueIn this paper, an extension of the HWM is used to calculate the IM, which, in contrast to the HWM, models the saturation. Furthermore, the simulation results of the different electromagnetic IM models are put into the context of the uncertainty of a measurement of several identical IMs.

Research on the Force-Sensitive Characteristic of InAs QD Embedded in HEMT.

A force-sensitive structure of an InAs Quantum Dot (QD) embedded in a high electron mobility transistor (HEMT) is presented in this paper. The size of an InAs QD is about 30 nm prepared by the S-K growth mode, and the force-sensitive structure is fabricated by molecular beam epitaxy (MBE). The force-sensitivity characteristic of the QD HEMT is studied by the electrical and mechanical properties. The electrical characteristics show that the InAs QD-HEMT has linear, cut-off, and saturation operating states, and produces different output currents under different gate voltages, which shows that the structure is reasonable. Furthermore, the results of the output characteristics under different pressure show that the output voltage of the QD-HEMT decreases with the increase in pressure, which indicates that the InAs QD-HEMT has a vital mechanical–electrical coupling characteristic. The output voltage of the InAs QD-HEMT in the range of 0–100 kPa shows that the sensitivity was 1.09 mV/kPa.

Analog performance of GaN/AlGaN high-electron-mobility transistors

In this paper, the analog properties of advanced GaN/AlGaN High-Electron-Mobility Transistors (HEMTs) are studied as a function of temperature (T). The drain current, the threshold voltage, the transconductance and the output conductance are experimentally investigated under saturation operation. Moreover, important figures of merit for the analog performance, such as transconductance-over-drain current, Early voltage and intrinsic voltage gain are analyzed for different channel lengths in the temperature range of 25 °C till 200 °C. The results indicate that due to change in the Fermi potential, the analog parameters reduce with increasing T. Furthermore, the performance increase for longer channel devices is correlated directly with the lower drain electric field penetration.

Tackling control channel saturation for load balancing in multi-channel mobile ad hoc networks

Multiple wireless channels in Mobile Ad hoc Networks (MANET) promises to improve Quality of Service (QoS) and their well coordinated usage can result in significant operational improvements. Traditional methods implementing multi-channels in MANET uses control channel based approach for synchronization and coordination among multiple channels. Control channel is a separate and dedicated channel reserved for performing channel negotiations and other control operations. In multi-channel MANET, conventionally all mobile devices have to resort to the control channel for channel reservation during a well defined beacon interval. This approach requires tight synchronization and works well when magnitude of traffic and node density is moderate. With the rise in traffic and node density, the control channel becomes saturated and network operation is compromised. The paper proposes Parallel Rendezvous Multi-Channel MAC (PRMMAC) protocol based on the concept of multi-channel communications and results reflects that it resolves the basic saturation of the control channel and ensures a balanced load among multiple channels catering to data communication needs. Key findings of the proposed system has been observed in terms of throughput, frame delivery ratio and delay under varied networks and channel configurations and significant performance improvement in terms of throughout delay and Frame Delivery Ratio (FDR) has been observed in comparison to other protocols of its category.

Thermal integration of reheated organic Rankine cycle (RH-ORC) with gas turbine exhaust for maximum power recovery

Reheating is a potential modification to the organic Rankine cycle architecture. Reheated ORC (RH-ORC) is integrated as bottoming cycle plant for topping high efficiency, recuperated gas turbine cycle with low exhaust temperature in the present study. The exit temperature of the working fluid after internal heat exchanger (IHE) sets the initial qualifying criterion. Cyclopentane, hexane and benzene qualify as potential working fluids and ORC with saturated operating conditions with these working fluids is considered as base cycle. For a power generating cycle, power recovery becomes priority over efficiency when connected to a waste heat recovery source. The performance of RH-ORC is studied at various reheat pressure ratios for different temperatures. Specific net work output of base cycle increases by retrofitting reheating and it leads to enhanced power recovery. Benzene, at a reheat pressure ratio of 0.558 produces maximum power output of 1292.033 kW and 4772.631 kW from the integration of SM-50 and Rolls-Royce WR-21 for a case of reheating at a temperature of 557.15K. The power recovery potential improves when reheating is carried out to a higher temperature. There is an increase in exergy efficiency because of reheating.

Investigations of photoresponse characteristics of ultrasonic spray pyrolysis deposited zinc oxide-based phototransistors at different quiescent points

How quiescent-points affect the performance of the ultrasonic spray pyrolysis deposited zinc oxide-based phototransistor is investigated in this study. It is well known that gate bias and drain bias control quiescent-points. By changing gate bias, strong accumulation, weak accumulation, weak depletion, and strong depletion in the active layer of the phototransistor are obtained. Meanwhile, by changing drain bias, either triode or saturation operation regions of the phototransistor is obtained. Therefore, total 8 different quiescent-points are investigated in this study. The material characteristics such as crystal structure, oxygen deficiency, bandgap, and trap energy levels are characterized. Moreover, the performance of the phototransistor at different quiescent-points are investigated. The present phototransistor shows four operation modes, including high responsivity, high UV-to-visible rejection ratio, fast response speed, and high specific detectivity, and each mode corresponds to a specific quiescent point.

Zero Temperature Coefficient behavior for Ellipsoidal MOSFET

The zero temperature coefficient (ZTC) is investigated by three-dimensional numerical simulations in the Metal-Oxide-Semiconductor (MOS) Field Effect Transistor (MOSFET) with the ellipsoidal (EM) and conventional rectangular gate geometries (CM), considering the same channel widths (W), gate areas (Ag) and bias condition (BC). In this work an improved simple model which predicts the ZTC point taking into account only the mobility degradation factor (c) and threshold voltage (Vth) parameters as function of temperature is proposed in the linear and saturation operation regions. The analysis takes into account the temperature variations of the threshold voltage and the mobility degradation factor. Although simple, the model predictions present a good agreement with the numerical simulations results.