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The gas lift technique applies gas bubble injection into the vertical wells to raise production. Gas and liquid rates, shifts in flow regimes, and system equilibrium influence this process. This study explores the efficient implementation of gas lift techniques to maximize production from the Asmari Formation in the Abu Ghirab Field, southeastern Iraq, using a continuous gas lift for maximum production rate by PIPESIM TM software. The results of the gas lift design for the four wells (AGCS-33, 26, 28, and 36) show that the Vogel method provided the best results for the gas lift design, and faults and facies distribution impact the gas lift injection and oil production rates. These will become evident with wells AGCS-33 and 36 as their proximity to faults will increase oil production rates with a gas injection rate limit of 7 MMSCF/d. Conversely, for wells 26 and 28, the limit will marginally rise, starting at 5 MMSCF/d. In addition, the effect of gas lift is clearly in the middle western of the crest, which shows an increasing percentage of oil production of 136.6% at minimum rate and 198.5% at maximum for the well AGCS-26, 89.7% and 105.7% for the well AGCS-36. Wellhead pressure has a significant impact on gas-lift performance, and improving gas-lift efficiency can be accomplished using an electric control valve. The feasibility of implementing gas lift in the Asmari Formation depends on the water cut, well location, and water saturation distribution within the Formation. [ABSTRACT FROM AUTHOR]

This paper developed a method for more accurate permittivity extraction of high-loss materials using the waveguide method to reduce the effect of the air gap. This method improves the Baker-Jarvis algorithm. It makes the errors of S-parameters caused by the air gap compensated by a correction factor β of the form: (S21 + S12) + β(S11 + S22). In our study, the correction results of β for materials on different frequencies and air gap sizes are quantitatively investigated. Furthermore, we propose a method to obtain an optimal frequency-independent β for different materials. A typical high-loss BeO-SiC ceramic commonly used in vacuum electron tubes is analyzed and discussed in detail. It shows that compared to traditionally utilizing only S21 (β = 0), adopting an optimal β can reduce the average errors of the complex permittivity from 17.7% to 7.9% with a 0.10 mm air gap. The proposed method is verified by measurements of unshaved and shaved samples. [ABSTRACT FROM AUTHOR]

Machine transplanting has been the primary technique of rice seedlings in cultivation in recent years. Among them, factory-scale greenhouses have been commonly used for seedling cultivation in northern China. By contrast, paddy-field seedling can be widely used to cultivate rice transplanting in southern China, according to climate, environment, and production costs. However, manual seedlings are limited to the high labor intensity and the waste of chemical fertilizers and pesticides. It is very necessary to improve the irrigation uniformity in the management of water-fertilizer-pesticide in rice paddy fields. In this study, a variable-rate spraying device was designed for water-fertilizer-pesticide irrigation in rice seedlings. A systematic analysis was performed on the large variable-rate sprinkler and the supporting equipment of fertilizer injection at a high-quality level. The overall structure and working principle were clarified for the variable-rate spraying irrigation device of waterfertilizer-pesticide for seedlings; FLUENT software was used to conduct numerical simulation on the sprinkler irrigation variable-diameter pipeline, in order to determine the optimal structural layout of variable-diameter pipeline; The flow rate of sprinkler and the inlet water of main pipe were then determined after experiments. The curved surface model was established for the pressure and electric ball valve opening; A fertilizer injection and dosing mechanism were designed using proportional integral derivative (PID) self-tuning. The real-time equal-proportion fertilizer or medicine injection was realized after optimization. The online control system of fertilizer injection and variable-rate spraying was constructed with the mitsubishi programmable logic controller (PLC) as the control core. The Box-Behnken experiment was adopted to explore the uniform performance and influencing factors of the device for spraying irrigation. The single objective optimization was applied to determine the key parameters of the device for sprinkler irrigation. The optimal combination of parameters was obtained as follows: The inlet water pressure of the main pipe was 0.20 MPa, the electric ball valve opening was 90°, and the nozzle spraying angle was 80°. Christiansen uniformity of the device was 92.69% in this case; There was a linear model between the mass concentration and electrical conductance (EC) value of the potassium chloride fertilizer solution. The variable-rate irrigation and fertilization experiments were conducted on the device. The EC values of the water-fertilizer mixture were 1.65, 1.66, and 1.68 mS/cm, respectively, in the three spraying irrigation levels. The average values of sprinkler intensity were 900.85, 1092.04, and 1263.67 mm/h, respectively. The fertilization uniformity coefficients were 85.21%, 87.86%, and 91.62%, respectively. There was a small fluctuation of EC values for the water-fertilizer mixtures under the three sprinkler irrigation levels of Ⅰ, Ⅱ, and Ⅲ. The average irrigation intensity of sprinklers varied greatly, where the coefficient of uniformity of fertilizer application was higher than 85%. The field test of rice seedlings was carried out using the variable-rate spraying device of water-fertilizer-pesticide for seedlings. The rice varieties were selected as Huahang51 conventional rice and Guang8You165 hybrid rice. The uniformity of seedling growth was higher than 95% at 13, 21, and 28 d after seeding. There were excellent quality indexes and rooting performance of the seedlings. The various quality indicators of rice seedlings fully met the requirements of machine transplanting. The experiment results showed that the variable-rate spraying device of waterfertilizer-pesticide system shared an accurate, real-time, and proportional fertilizer injection, irrigation, and pesticide spraying in rice paddy fields. The finding can provide a practical application to improve the mechanization level of rice paddy field seedlings for the high-quality of seedlings. [ABSTRACT FROM AUTHOR]

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As the noise of engines in factories results in hearing damage, it is mandatory to install silencers. Traditional noise abatement practices involve using one silencer for each venting noise source, leading to cost increase issues when multiple intermittent venting noises are present. Thus, the need for a smart system capable of switching the venting duct to a specific silencer becomes crucial. To address this need, a smart duct switching system is proposed, integrating electric valves, microphones, a controller, and a single silencer. To enhance noise reduction, various types of silencers are examined to investigate their performance in noise reduction. A finite element method (FEM) was adopted to simulate and evaluate the degree of noise reduction. The transmission loss (TL) of silencers with screw tubes (silencer A), expansion cones (silencer B), orifice plates (silencer C), and perforated tubes (silencer D) was evaluated by simulation with COMSOL software. The results indicated that screws did not reduce noise effectively even when combined with expansion cones, orifice plates, and perforated tubes. However, expansion cones, orifice plates, and perforated tubes effectively decreased noise, and their performance was higher when used without screws. Among the various devices, perforated tubes reduced noise most significantly. [ABSTRACT FROM AUTHOR]

Urban utility tunnels have developed rapidly in recent years. The effective ventilation system maintains the air quality of the utility tunnel. In order to improve the ventilation performance of utility tunnel, a three-dimensional model of utility tunnel was established according to the design drawings. Based on Fluent 14.0 software, a flow model was established. And numerical simulation methods were used to study the optimization of air ducts and ventilation methods. The utility tunnel used top ventilation and interlayer ventilation. The ventilation methods of different ventilation areas of urban utility tunnels are compared. The results showed that the combination of operational gain and ventilation zone length mainly affected the ventilation effect. Based on the simulation results, a comprehensive ventilation mode consisting of top ventilation, natural ventilation at 400 m long entrance and mechanical outlet exhaust was proposed. Electric valve, fire door, exhaust fan and induction fan could be opened in the urban public utility tunnel at low speed. This new combination method is considered the optimal combination method for the maximum ventilation speed of urban utility tunnels. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopadie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Field emission is an important work mode for electron sources, and carbon nanotubes (CNTs) have been extensively studied for their good emission properties. It is well known that the parameters of the grid deeply influence the field emission performance of CNTs, a relationship that requires further elucidation. Therefore, in this study, the relationship between the grid aperture ratio and electron transmittance was studied through simulations and experiments. This study's results indicate that the electron transmittance improved as the grid aperture ratio increased. Meanwhile, electron beam spot simulations and imaging experiments indicate that an increased grid aperture ratio will expand the cathode electron divergence, leading to a larger electron beam spot size. These results demonstrate that there is a trade-off in maintaining the grid aperture ratio between high electron transmittance and relatively small electron beam spot size, and the optimum grid aperture ratio is between 75% and 85%. These results will provide a reference for the design and optimization of X-ray tubes and other electron sources. [ABSTRACT FROM AUTHOR]

Infant breastfeeding diagnostics remain subjective due to the absence of instrumentation to objectively measure and understand infant oral motor skills and suckling characteristics. Qualitative diagnostic exams, such as the digital suck assessment which relies upon a clinician's gloved finger inserted into the infant's mouth, produce a diversity of diagnoses and intervention pathways due to their subjective nature. In this paper, we report on the design of a non-nutritive suckling (NNS) system which quantifies and analyzes quantitative intraoral vacuum and sucking patterns of full-term neonates in real time. In our study, we evaluate thirty neonate suckling profiles to demonstrate the technical and clinical feasibility of the system. We successfully extract the mean suck vacuum, maximum suck vacuum, frequency, burst duration, number of sucks per burst, number of sucks per minute, and number of bursts per minute. In addition, we highlight the discovery of three intraoral vacuum profile shapes that are found to be correlated to different levels of suckling characteristics. These results establish a framework for future studies to evaluate oromotor dysfunction that affect the appearance of these signals based on established normal profiles. Ultimately, with the ability to easily and quickly capture intraoral vacuum data, clinicians can more accurately perform suckling assessments to provide timely intervention and assist mothers and infants towards successful breastfeeding outcomes.

Semiconductor manufacturing demands a fast delivery of multiple gases to the tool. Hence this document provides formulas for the fluid-mechanical timescales of this delivery. This is done with a simple but realistic model of a gas-supply system, together with theory and computational-fluid-dynamic (CFD) simulations, and for representative but not comprehensive conditions relevant to etch. This timescale analysis shows that the rate-limiting process is (i) convection in the MFC-manifold tubing or (ii) convection in the tube between the flow splitter and the process chamber. This depends on (a) the lowest MFC sccm in the gas-supply system and (b) the total gas-supply-system sccm. Therefore, speeding up the gas delivery requires enhancing (i) and (ii). Moreover, (i) would become more important in view of a current trend towards smaller MFC sccms in etch. Examples on how to speed up the gas delivery and enhance the mixing are provided. The present analysis can be adapted to other conditions and manufacturing processes. [ABSTRACT FROM AUTHOR]

The communication between different cell populations is an important aspect of many natural phenomena that can be studied with microfluidics. Using microfluidic valves, these complex interactions can be studied with a higher level of control by placing a valve between physically separated populations. However, most current valve designs do not display the properties necessary for this type of system, such as providing variable flow rate when embedded inside a microfluidic device. While some valves have been shown to have such tunable behavior, they have not been used for dynamic, real-time outputs. We present an electric solenoid valve that can be fabricated completely outside of a cleanroom and placed into any microfluidic device to offer control of dynamic fluid flow rates and profiles. After characterizing the behavior of this valve under controlled test conditions, we developed a regression model to determine the required input electrical signal to provide the solenoid the ability to create a desired flow profile. With this model, we demonstrated that the valve could be controlled to replicate a desired, time-varying pattern for the interface position of a co-laminar fluid stream. Our approach can be performed by other investigators with their microfluidic devices to produce predictable, dynamic fluidic behavior. In addition to modulating fluid flows, this work will be impactful for controlling cellular communication between distinct populations or even chemical reactions occurring in microfluidic channels. [ABSTRACT FROM AUTHOR]

The solenoid valve for traction control valve (TCV) responsible for the automatic vehicle hold (AVH) function of electric vehicles require a continuous supply of power to the magnetic coil in order to operate. When power is continuously supplied, heat is generated because of the resistance of the magnetic coil, which leads to deterioration of the periphery of the solenoid valve and deteriorates durability. To prevent this, when power is applied to the solenoid valve for TCV for more than a certain period of time, the power supply is automatically turned off and the AVH function is controlled to be performed by the electronic parking brake (EPB). In this study, we designed, manufactured, and verified the permanent magnet solenoid valve of TCV for AVH that can minimize unnecessary power consumption of electric vehicle batteries. For the design of the permanent magnet solenoid valve, the location, polarity direction and specifications of the permanent magnet within the solenoid valve were studied through finite element analysis. In order to check whether the braking function by the permanent magnet is maintained even when the current is cut off at AVH's TCV solenoid valve, electronic control unit (ECU) and electronic stability control (ESC) were manufactured and evaluated for actual vehicle testing. Therefore, it was possible to manufacture a permanent magnet solenoid valve that minimizes unnecessary power consumption of the battery because it does not require power supply even when the car is stopped for a long time in the AVH function of the electric vehicle. [ABSTRACT FROM AUTHOR]

LQXFA/B production series cryogenic assemblies are being built for the LHC upgrade by the HL-LHC Accelerator Upgrade Project (AUP). These contain a pair of MQXFA quadrupole magnets combined as a cold mass within a vacuum vessel, and are to be installed in the IR regions of the LHC. The LQXFA/B are being tested at 1.9 K to assess alignment and magnetic performance at Fermilab's horizontal test facility. The ∼10 m long assembly must meet stringent specifications for quadrupole strength and harmonic field integrals determination, magnetic axis location, and for variations in axis position and local field profiles. A multi-probe, PCB-based rotating coil and a Single Stretched Wire system are employed for these measurements. To accurately determine rotating coil location and angles within the cold mass, a laser tracker is utilized to record multiple targets at one end of the probe. This paper describes the measurements, probes/equipment, and techniques used to perform the necessary characterization of the cold mass.

Fluid wave code communication is used in layered water injection intelligent monitoring system, but model of fluid transient flow wave signal transmission is still unknown. Based on the fluid energy equation of steady flow, a transmission mathematical model of fluid transient flow wave signal in intelligent layered water injection system was established. The model can accurately describe the transient flow wave transmission characteristics in the tubular string of water injection wells. The transient flow wave signals and influencing factors generated by the ground electric control valve and the downhole water distributor were studied, and the transmission mechanism of the signal in the water injection tubular string was revealed. Studies show that ground and downhole transient flow wave signals are generated by discharge changes caused by changes in the opening degree of the ground valve and the downhole water distributor. The length of the water injection tube has no effect on the downlink transmission of the wellhead signal, but has a certain influence on the uploading of the downhole signal. Numerical calculations show that the flow rate of the water injection tube has a great influence on the amplitude of the pressure signal. The larger flow rate can generate larger signal amplitude, which is beneficial to the signal transmission, signal detection and processing. It was verified by the experiments and simulations that the pressure and flow changes in the downhole and wellhead had good consistency during the transmission of transient flow waves. It is found that the greater the variation of opening degree, the greater the amplitude of transient flow wave signal, which is beneficial to the wave signal transmission. The optimal settings for the valve opening are selected as 100 % ⇄ 0 % . This study has theoretical guiding significance for the design and performance improvement of fluid wave code communication systems. [ABSTRACT FROM AUTHOR]

This article proposes a design method for a valve automatic assembly production line in response to the automation assembly requirements of electric valve products in space propulsion systems and the engineering problems of inaccurate loading force control and low valve measurement accuracy in existing process methods. This method can achieve five assembly processes during the assembly process of electric valves, including pre-tightening force control, valve-core stroke measurement, performance testing, and shell structure welding. The article introduces the design of platform components such as process execution, positioning, and transportation, as well as the design and operation process of workstations. By combining the design of a three-axis motion mechanism, a small turntable, and a robotic arm, the product can achieve professional, positioning, full process automation, and equipment miniaturization design across multiple workstations. Through the design of precise control of loading force and non-contact optical measurement method of moving structure, compared with the original method, the parameters affecting product performance are precisely controlled and the precision is improved. And the multivariable decoupling of valve product performance is realized by this method. Through application verification, this automatic assembly production line can significantly improve the assembly efficiency of electric valve products and solve difficult problems in product engineering. [ABSTRACT FROM AUTHOR]

To solve the problem that the parameters of the multiple-input multiple-output (MIMO) irrigation system are difficult to control accurately, an on-demand irrigation control experimental device was developed. The main input parameters of the device are the opening degree of the main pipe valve, the opening frequency of and the pump station, the opening degree of the branch pipeline valve with the different combinations of different opening degrees. Based on these input parameters, four types of experimental methods were designed, and a total of 1695 groups of experiments were designed. The results show that the different opening degree combinations of the branch electric valve cannot significantly affect the flow of the branch pipeline but also significantly affect the pressure of the main pipeline. The prediction error of the operating frequency of the pump station and the opening degree of the branch valve were regarded as the objective function. Six intelligent prediction models were constructed, which are Back Propagation (BP), support vector regression (SVR) Linear, SVR-RBF, SVR-Poly, random forest (RF) and eXtreme Gradient Boosting (XGBoost), respectively. The results show that the XGBoost is the best model among the six models. For the opening degree of three branch valves, the mean absolute error (MAE) between the predicted value and actual value is less than 3.3%, the mean square deviation (RMSE) between the predicted values and actual values is less than 4.5%, and the R2 of between the predicted values and actual values is greater than 0.990. The control models and system can meet the needs of an on-demand irrigation system. [ABSTRACT FROM AUTHOR]

The traditional canned electric valve consists of an induction motor and a reducer, which need to be matched with the position sensor to achieve precise control of valve position. The position sensor and reducer are not only easily damaged in high-temperature liquids, but also the slip rate of the induction motor is greatly affected by the liquid temperature, which makes it difficult to achieve accurate control. To address the above problems, this paper introduces a new topology of canned electric valve permanent magnet synchronous motor (CEV-PMSM), and a new maximum torque per ampere (MTPA) model is proposed. The new MTPA control equation considering the canned sleeve parameters is derived theoretically. By comparing it with id = 0 control and ideal MTPA control strategy, it is proved that the new MTPA model reflects the electric valve operation characteristics more realistically. In order to achieve sensorless control of the electric valve, and to achieve fast response and high-precision control under external disturbances and parameter uncertainties, the proposed control scheme combines sensorless control and two-degree-of-freedom (2-DOF) control. Consequently, the proposed control scheme can effectively improve the static and dynamic performances of the CEV-PMSM, as well as adjust the tracking and anti-disturbance performances independently. Finally, a 2 kW 100 r/min prototype was manufactured and corresponding experiments were conducted to verify the accuracy of the analysis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The application of control systems in precision irrigation is critical to ensure the accurate distribution of water in crops under various uncertainties. Shifts in the loading of the water supply on the control valve can be a significant uncertainty. Changes in weather and the uncertainty of the water level in the reservoir are also challenging issues. Sliding Mode Control (SMC) is a robust control technique that is simple to apply to deal with uncertainty, while Fast Terminal Sliding Mode Control (FTSMC) has the benefit of the rapid convergence. The DC electric motor, which is a common component of electric control valves, can be employed in designing control techniques for precision irrigation applications. This study aims to design a proposed experimental-based method, namely FTSMC for valve regulation under water load uncertainty for precision irrigation application. Modification of the signum function should be used to eliminate the chattering effect in real experiments.The results of experiments showed that the proposed method was superior to the conventional Proportional Integral Derivative (PID) and traditional SMC techniques in terms of overshoot, convergence rate and error. Because of those reasons, the FTSMC approach should be implemented on control valves against load uncertainty in precision irrigation applications. [ABSTRACT FROM AUTHOR]

In order to solve the problem that the traditional industrial control methods cannot control the heating flow and water temperature in a timely and effective manner due to the high delay and complex coupling characteristics of the urban central heating system, the authors propose deep learning-based data processing and management for thermal heating systems. The author analyzes the non-ideality of district heating system and its influence on the application of deep learning technology, and gives solutions, respectively, finally, a primary side regulation scheme of district heating system based on deep learning and automatic control technology is proposed as a whole. The experimental results show that, by comparing the water supply temperature predicted by the equipment model of the primary side heat station with its actual measured value, the mean square error of the prediction results using the model directly is 1.30%, and the mean square error after model correction is 0.094%. The secondary return water temperature was controlled by adjusting the opening of the primary side electric valve, the expected secondary return water temperature in the scheme was compared with the actual secondary return water temperature, and the mean square error was 0.102%. It is proved that the scheme can achieve good control effect in the actual system, and the data result proves that the scheme is feasible. [ABSTRACT FROM AUTHOR]

Single-wall carbon nanotubes (SWCNT), which consist of a two-dimensional hexagonal lattice of carbon atoms, possess unique mechanical, electrical, optical and thermal properties. SWCNT can be synthesized in diverse chiral indexes to determine certain attributes. This work theoretically investigates electron transport in different directions along SWCNT. The electron studied in this research transfers from the quantum dot that can possibly move to the right or left direction in SWCNT with different valley-dependent probability. These results show that valley polarized current is present. The valley current in the right and left directions has a composition of valley degrees of freedom where its components (K and K′) are not identical. Such a result can be traced theoretically by certain effects. That firstly is the curvature effect on SWCNT in which the hopping integral between π electrons from the flat graphene is altered, and another is curvature-inducing σ - π mixture. Due to these effects, the band structure of SWCNT is asymmetric in certain chiral indexes leading to the asymmetry of valley electron transport. Our results exhibit that the zigzag chiral indexes is the only type making electron transport symmetrical that is different to the result from the other chiral index types which are the armchair and chiral. This work also illustrates the characteristic of the electron wave function propagating from the initial point to the tip of the tube over time, and the current density of the probability in specific times. Additionally, our research simulates the result from the dipole interaction between the electron in QD and the tube that impacts the lifetime of the electron being in QD. The simulation portrays that more dipole interaction encourages the electron transfer to the tube, thereby shortening the lifetime. We as well suggest the reversed electron transfer from the tube to QD that the time duration of such transfer is much less than the opposite transfer owing to the different orbital of the electron's states. Valley polarized current in SWCNTs may also be used in the development of energy storage devices such as batteries and supercapacitors. The performance and effectiveness of nanoscale devices, including transistors, solar cells, artificial antennas, quantum computers, and nano electronic circuits, must be improved in order to achieve a variety of benefits. [ABSTRACT FROM AUTHOR]

The electromagnet pneumatic proportional servo valve is widely used in industrial automation, medical equipment, scientific composition detectors, and other fields that require precise adjustment of high-pressure air flow due to its simple working structure, large output power, large working frequency response, and good control performance. However, the output pressure of the valve is small, making it vulnerable to the impact of the external environment. Based on the practical electromagnet-type pneumatic proportional servo valve, this paper establishes a finite element dynamic mathematical model, conducts finite element analysis on the electromagnet magnetic field in the valve, then improves the structural parameters of the original proportional valve through the analysis of the valve performance parameters and structural optimization, and finally, the physical experiment proves that the optimized electric proportional valve can effectively reduce the hysteresis within the working pressure range and has good response characteristics to step signals. This paper can provide support for performance analysis and structural parameter improvement of the electric proportional valve. [ABSTRACT FROM AUTHOR]

Copyright of Electric Drive is the property of Electric Drive Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To research the influence of the proportional relay valve on the economy and safety of the electric bus through the braking recovery system, a proportional relay valve model was proposed. Based on the analysis of the structure and working principle of the solenoid on/off valve, a dynamic model of "electro-magnetic-machine-air" coupling was simulated and analyzed. Then, based on the solenoid on/off valve and proportional relay valve, two pressure regulator modules were designed, the braking energy recovery system schemes were designed, respectively. Fuel economy tests were carried out under China city bus typical driving cycle based on two kinds of air pressure regulating module to research the influence of the proportional relay valve on the economy of the electric bus. An integrated control system of braking energy recovery and anti-lock braking system based on the proportional relay valve was proposed, hardware-in-the-loop braking energy recovery system contrast tests of the anti-lock braking system were also carried out based on two kinds of air pressure regulating module. The test results indicated that the proposed braking energy recovery system schemes were effective. The test results also demonstrated the economic contribution rate of the braking energy recovery of the proportional relay valve pneumatic control module was slightly higher than that of the proportional relay valve. Meanwhile, the proportion relay valve pressure regulating module achieved a good target speed follow and the accurate adjustment of air pressure in anti-lock braking system control. [ABSTRACT FROM AUTHOR]

To improve the dynamic response speed of high-speed solenoid valves in electric fuel injection systems of marine diesel engines, a numerical simulation model of the solenoid valve is described in this paper. The accuracy of the simulation model was verified on the test bed of the solenoid valve. The effect of the punch position and the size of the dynamic response of the solenoid valve were investigated by using the distribution law of the electromagnetic force in the armature. The results of the test showed that armature drilling in the inter-yoke zone can optimize the solenoid closing response time, but it has little impact on the solenoid opening response time. From this rule, two groove schemes were further designed. Through comparison and calculation, it can be concluded that the fan groove scheme is better than the trapezoidal groove scheme, and that the opening and closing response times of the solenoid valve should be targeted in order to multi-target optimize the fan groove geometric parameters and the armature thickness. The results show that after optimization, the weight of the motion part is reduced by 21.6%, the opening response time of the solenoid valve is reduced by 11.1%, and the closing response time is reduced by 30.0%. While reducing the oil film damping of the armature motion, the overall dynamic response characteristics of the solenoid valve are improved. [ABSTRACT FROM AUTHOR]

This paper presents a state-of-the-art review of the literature concerning flow-induced noise in expansion devices. The topics covered are theoretical natural frequency models of bubbles with spherical and cylindrical shapes and flow-induced noise in capillary tubes, such as orifice, thermal and electric expansion valve. Several parametric conditions affect the flow-induced noise in capillary tubes, such as outlet capillary geometry, capillary inner diameter and length, flow orientation, outlet vapor quality, mass velocity, pressure drop, in/outlet flow pattern, evaporation temperature, and refrigeration cycle operational conditions. Despite the broad use of orifice, there is a lack of knowledge in the literature of flow-induced noise in these devices. The flow-induced noise seems primarily a function of mass velocity, vapor quality, and flow pattern. It seems that outlet intermittent flow patterns lead to significant noise in capillary tubes and expansion valves. In general, for the noise evaluated outside the expansion device, electric expansion valves exhibited higher sound pressure levels than capillary tubes. Furthermore, the present literature review indicates that efforts should be made to perform tests for a wide range of conditions evaluating the noise within and outside the expansion device, device wall acceleration and flow topology for current and new refrigerants, simultaneously. [ABSTRACT FROM AUTHOR]

Conditioning temperature is one of the key factors in the quality of feed pellets during feed processing. It is a high demand to maintain the constant conditioning temperature. Specifically, too high conditioning temperature can lead to the inactivation of heat-sensitive ingredients, such as probiotics, whereas, too low conditioning temperature can be found in the incomplete sterilization of the starch paste. In this study, a Proportion Integration Differentiation (PID)-based control system was developed to control the conditioning temperature of the feed pellets during processing. The whole unit consisted of a control system, steam piping, and a pelletizer. The control system with a Programmable Logic Controller (PLC) and a touch screen was utilized to control the start/stop of the pelletizer and the opening of the electric regulating valve. The process parameters of the pelletizer were also automatically collected, according to the given time interval. A temperature sensor was installed at the outlet of the pelletizer. The PT100 temperature sensor was used to collect the conditioning temperature of the material at the outlet of the temperature in real time. Subsequently, the collected data was fed back to the PLC. The PID closed-loop control algorithm was utilized to calculate the electric actuator again after the appropriate adjustment of the parameters. The stable control of tempering temperature was realized to change the steam flow into the temperature. A systematic analysis was made to obtain the convective heat exchange process between the mixed feed and steam at temperature. A theoretical model of heat transfer was established to obtain the specific parameters using the step response curve method. After that, the data curve was processed (R² = 0.976) to obtain a control model between the electric proportional control valve and the tempering temperature in the control system. As such, a large influence of special points was avoided on the experimental data after processing. Furthermore, the simulation analysis was carried out to determine the optimum parameters for the PID control using the Simulink platform. A comparison was performed on the response curves from three PID parameter regulations, namely the Z-N regulation, the decay curve method, and the critical proportional method. Finally, the critical proportional method was found to present the best control effect, in terms of the overshoot and regulation time in the dynamic performance indicators with the PID parameters (proportionality coefficient Kp=52.7, integral coefficient Ti=6.4, and differential coefficient Td= 1.6). The response time of the PID controller obtained by the critical proportionality method was 14 s and the overshoot was 3.3 ℃. Taking the lactating sow meal as an example, a series of prototype tests were carried out on the pelletizer. Specifically, the lactating sow meal was first crushed with the 1.5 and 2 mm sieves. The moisture content of the mixture was 10.17%, while the tempering temperature was set at 75, 80, and 85 °C. The tempering temperature was maintained within the set range after stability. Subsequently, the tempering temperature of 80 °C was chosen for the stability test. The tempering temperature was recorded every 1min during the test. The basically stable tempering temperature was achieved in the whole test process, which was controlled within (80±1) ℃, indicating the small average relative error and coefficient of variation of temperature. Therefore, the stable control of system temperature can be expected to automatically collect the pelletizing production data. Anyway, the control system can be expected to serve as the rapid response and real-time control of tempering temperature in the pelletizing process. Furthermore, the processing operation was simplified to improve automation in pelletizing production. [ABSTRACT FROM AUTHOR]

We investigate how the electrical conductivity of a functionalized nanotube affects its absorption of THz radiation. The nanotube is a periodic structure made from C60 fullerenes that are regularly polymerized with each other and with a nanotube wall with a step of several nanometers. A K+@C60 complex, where K+ is a positive potassium ion, oscillates freely in the THz range in a potential well in the nanospace between polymerized fullerenes. Increasing the vibration amplitude of the K+@C60 complex at the resonance frequency redistributes the electron density on the tube and creates a partial flow of charge to the fullerene frame of the complex, which changes the conductivity of the nanotube by several percent, depending on the applied voltage. This phenomenon can form the basis of a nanodevice for detecting THz radiation. [ABSTRACT FROM AUTHOR]

In point cloud videos, point coordinates are irregular and unordered but point timestamps exhibit regularities and order. Grid-based networks for conventional video processing cannot be directly used to model raw point cloud videos. Therefore, in this work, we propose a point-based network that directly handles raw point cloud videos. First, to preserve the spatio-temporal local structure of point cloud videos, we design a point tube covering a local range along spatial and temporal dimensions. By progressively subsampling frames and points and enlarging the spatial radius as the point features are fed into higher-level layers, the point tube can capture video structure in a spatio-temporally hierarchical manner. Second, to reduce the impact of the spatial irregularity on temporal modeling, we decompose space and time when extracting point tube representations. Specifically, a spatial operation is employed to encode the local structure of each spatial region in a tube and a temporal operation is used to encode the dynamics of the spatial regions along the tube. Empirically, the proposed network shows strong performance on 3D action recognition, 4D semantic segmentation and scene flow estimation. Theoretically, we analyse the necessity to decompose space and time in point cloud video modeling and why the network outperforms existing methods. [ABSTRACT FROM AUTHOR]

A novel analysis for a new type of variable reluctance resolvers (VR-Resolvers) with toroidal windings based on the magnetic equivalent circuit (MEC) method is presented in this work. Different cases including various windings configurations as well as different rotor structures are considered in order to investigate the performance of the resolver precisely. The position error of both healthy and eccentric resolvers are studied by a flexible MEC model. The effect of the eccentricity fault on the resolvers with different specifications is also evaluated to analyze the manufacturing tolerance due to the eccentric rotor for several cases. It is notable that the presented MEC provides the opportunity to adjust accuracy and model several structures in both healthy and faulty conditions by just a single model. Finally, the MEC results are confirmed by finite element method and experimental results to show the effectiveness of the proposed model. In general, development of a new VR-Resolver and analyzing its performance under different windings configurations and rotor structures by proposing a modified MEC approach are the paper novelties. [ABSTRACT FROM AUTHOR]

Accurate monitoring of contaminants, such as wear particles in lubricating oil, is critical for the efficient maintenance of engines. Here, a TE011-mode cylindrical cavity resonator-based sensor system is presented. In the measurement, a glass test tube was used to contain the oil sample under test and placed in the center of the cavity. Particles in oil change the dielectric properties and perturb the resonance parameters, thereby achieving sensing. Sensitivity to both the presence of conductive and nonconductive powders is demonstrated. Linear relationships between the powder weight and the quality factor are established. Hence, the degree of contamination can be better evaluated compared with existing microwave sensors. Powder differentiation can be achieved using the resonance frequency and quality factor. In addition, analytical modeling of the sensing system incorporating field analysis is proposed, and the effective permittivity of the mixture can be determined. The sensor developed is compact, portable, easy to implement, complementary to other approaches for liquid evaluation, and has the potential for high-throughput online measurement. [ABSTRACT FROM AUTHOR]

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Accurate calculations of electronic stopping power (ESP) are critical to understanding ion–solid interactions for charged particle slowing down in materials. Basing on the nonadiabatic results from the time-dependent density-functional theory (TDDFT) for H ion intruding through single wall carbon nanotubes, we analyze and quantify the strength of the ion–solid interaction by tracking the momentum of the target atom. The slow-moving H is subjected to a friction force when the ion–solid interaction is weak. When the interaction is strong, the electrons in tube are excited and the coulomb repulsion between H ion and target atoms gradually dominates. A piecewise fitting physical model for ESP as a function of the impact parameter is built to show the dependency of ESP on impact parameters. These results explain energy loss of charged particles in matter at high-speed or large off-channel condition and provide a basis for understanding ion–solid interactions in more complex systems. [ABSTRACT FROM AUTHOR]

Objectives. To evaluate and compare the impacts, bond strength, residual adhesive, and time invested on the enamel surface after debonding of recently introduced ceramic buccal molar tubes with different systems. Materials and Methods. Ceramic molar tubes were bonded to fifty-four maxillary molar teeth, and a shear bond strength (SBS) test was performed. The adhesive remnant index (ARI) scores were recorded, and the samples were divided into two groups for adhesive removal with low-speed instruments: tungsten carbide bur or diamond-coated micropolisher point. The time to clean the enamel surfaces was also noted down for each tooth. The enamel surfaces were investigated with scanning electron microscope (SEM) after adhesives were cleaned. Shapiro-Wilk's, Kolmogorov-Smirnov's, and Student's independent t tests were used for statistical analysis. Results. The mean SBS value of the tested ceramic molar tubes was 9.78 ± 1.85 MPa, and the majority of the samples were scored as ARI 1 and ARI 2. No statistically significant difference between PoGo micropolisher and TCB was found in terms of time values for surface cleaning. The enamel surface characteristics of TCB for adhesive remnant removal resulted in a better enamel surface than the single-step diamond polisher when the samples were investigated by using SEM. Conclusions. Ceramic molar tubes may be an enamel-safe product for patients seeking for fully aesthetic orthodontic treatment, if used in carefully handled clinical conditions. One-step polishing systems utilised with low-speed instruments could be used confidentially for cleaning the resin remnants on enamel after orthodontic treatment. [ABSTRACT FROM AUTHOR]

The design of electric valve actuators for explosion proof (Ex d) hazardous environments, whereby an explosive event must be contained, is examined in this study. Combustion within these small enclosed volumes is complex due to the irregular geometries developed in the design process, effectively producing a series of obstacles. These geometries lead to a scenario whereby combustion within the enclosed interconnected volumes produces the phenomenon known as pressure piling. A numerical method utilising OpenFOAM (Foundation), an open-source computational fluid dynamics (CFD) code, has been developed to simulate combustion within two interlinked vessels. OpenFOAM has not been validated extensively for simulating pressure piling. The numerical results are in good qualitative and quantitative agreement with a set of experimental data. A unique experiment conducted by the author, which introduces obstacles representing blockage ratios (BR's) is presented. Understanding the mechanisms of pressure piling will eventually lead to improved design techniques to control the effects of the over-pressures produced by these types of internal geometries. • Maximum over-pressure of the pressure piling effect can be increased by the introduction of obstacles. • Small geometrical changes can have a large impact on the over-pressures and therefore the pressure piling effect. • OpenFOAM has been utilised to model such events with results that are in good agreement. • Simulation benchmarking has proved the numerical method developed is accurately solving the physics correctly. [ABSTRACT FROM AUTHOR]

The dependence of overall traveling-wave tube (TWT) efficiency on the collector efficiency is of paramount importance. The objective of achieving high overall efficiency drives us to design a multi-stage depressed collector (MDC) with the theoretically highest possible efficiency with appropriate depressed potentials. Various design parameters, namely electrode geometry, depressed potentials, material parameters, etc., can be optimized to attain the desired theoretical maximum collector efficiency. But in a practical situation, the measured MDC efficiency is relatively less than the designed efficiency, which may be attributed to approximations involved in the nonlinear interaction of the electron beam and RF wave, fabrication inaccuracies, process limitations, simulation approximations, etc. This inexplicable practical decrease in MDC efficiency is typically accompanied by an increase in the backstreaming of electrons into the interaction structure. To compensate for this decrease, a permanent magnet has been suitably positioned on the base plate of the MDC, which results in an increase in collector efficiency. Simulation studies have been carried out to optimize the parameters of the magnet in terms of the geometrical dimensions, position, and magnetic field value, and has been validated experimentally. This technique of collector efficiency enhancement using an external magnet has proven to be very effective, contributing to a significant collector efficiency enhancement of > 5% from ~78% to ~83%, which in turn corresponds to an overall tube efficiency improvement of ~5.8% from 50.5% to 56.3%. [ABSTRACT FROM AUTHOR]

Since the 1980s, the single-core optical fiber cable has been the essential data transmission wiring media, with ongoing increases in deployments. Its use case has broadened, with transmission distances ranging from meters to 10000s km, including intrabuilding, fiber-to-the-home (FTTH), terrestrial, and even submarine trunk lines. Currently, optical fiber cable deployment is strongly driven by cloud-based storage, X as a Service (XaaS), and worldwide data center (DC) functionality with the optical interconnection of massive servers on DC campuses. Hence, it is quite natural that the optical fiber cable industry has developed ultrahigh fiber count, high density, and small diameter optical fiber cable, e.g., 6912-fiber-count cable. With high-density cables, massive data capacity can be installed at one time while saving limited space in an underground duct. High-density cable designs have been developed not just by cable structure optimization but through the process of bundling fibers and the use of high-grade optical fibers. Moreover, many enabling technologies have been developed to support the deployment of ultrahigh fiber count cables, such as fiber identification, connectors, mass fusion splicing, and storage systems for fusion splicing points. In this article, state-of-the-art technologies and prospects for ultrahigh-count and ultrahigh-density optical fiber cables and enabling technologies are explained. [ABSTRACT FROM AUTHOR]

In this article, an accurate analytical model for the calculation of the resonant length of a surface-wave-excited plasma antenna based on the distribution of the plasma density along the column is presented. In the proposed method, the propagation and attenuation constants for a surface-wave-excited plasma column are derived by solving the surface wave propagation problem on a three-layer tube, and as a result, the distribution of the plasma density along the column is investigated. Specifically, it is shown that a plasma column acts as a slow wave medium. Therefore, the resonant length of a plasma antenna is less than the resonant length of its metallic counterpart. For the experimental validation of the presented model, an efficient coupling structure for feeding the excitation wave to the plasma antenna is proposed that allows frequency tunability and reconfigurability of the antenna. A prototype of the proposed structure has been designed and fabricated. Good agreement between the analytical, numerical, and measurement results validates the proposed model. [ABSTRACT FROM AUTHOR]

Existing technologies for patients with respiratory insufficiency have focused on providing reliable assistance in their breathing. However, the need for assistance in other everyday respiratory functions, such as coughing and speaking, has remained unmet in these patients. Here, we propose Exo-Abs, a wearable robotic system that can universally assist wide-ranging respiratory functions by applying compensatory force to a user's abdomen in synchronization with their air usage. Inspired by how human abdominal muscles transmit pressure to the lungs via abdominal cavity compression, a biomechanically interactive platform was developed to optimally utilize the abdominal compression while aligning the assistance with a user's spontaneous respiratory effort. In addition to the compact form factor, thorough analytic procedures are described as initial steps toward taking the human respiratory system into the scope of robotics technology. We demonstrate the validity of the overall human–system interaction with the assistance performance under three essential respiratory functions: breathing, coughing, and speaking. Our results show that the system can significantly improve the performance of all these functions by granting on-demand and self-reliant assistance to its users. [ABSTRACT FROM AUTHOR]

The latest 2011 edition of the IEEE C57.100 standard introduced a new sealed tube accelerated aging test (STAAT) procedure and methodology for evaluating the thermal index (TI) of liquid-immersed transformer insulation systems. The application of this standard becomes increasingly important, as new insulating materials (both solid and liquid) have been developed, and their thermal performance shall be qualified. The experimental work presented in this article investigated the effects of different test parameters on the aging test results and data interpretation. The new findings on the dependence of the aging process on the ratio and type of materials in the system, as well as on the selected aging criteria provide a better understanding of the accelerated aging and interpretation of the data along with practical recommendations for the improvement of the test procedure. In parallel, for the first time, the TI of the Transformerboard, as a component of the so-called industry-proven insulation system, was investigated and defined based on the standard industry test. The results confirmed that the Transformerboard’s thermal class is, at least, 120 °C; this validates an empirically based application of this material as a part of the 120 °C class insulation system in both power and distribution transformers. [ABSTRACT FROM AUTHOR]

Multi virtual cathodes (MVCs) were created in an axial vircator utilizing two dielectric reflectors (DRs). The wall charge of drifting electrons on the surface of DRs led to the creation of VC2 and VC3 in the downstream area of drift tube, according to phase space simulations. The microwave generated by VC1 interacted with the charge of VC2 and VC3 to raise the power amplitude, resulting in an increase in output power from 284 MW to 1028 MW. The use of two dielectric reflectors was proven to have a remarkable impact in reducing electron loss, increasing output power, and improving efficiency. The suggested vircator’s efficiency with MVCs improved from 7.9 % to 28.6 %. The findings indicate important signs of progress in vircator research to decrease electron losses and boost beam–wave interaction, which might lead to the advancement of high-efficiency vircators. [ABSTRACT FROM AUTHOR]

In this work, a new complimentary split ring resonator (CSRR)-based sensor is proposed to sense chemical concentrations. A groove is created in the dielectric ring region of the CSRR to place the hollow tube containing the material under test (MUT). By placing the MUT in the region of high field concentration, higher sensitivity is achieved. The proposed novel and simple design alleviates the requirement of complex fluidic channels and space needed to place the MUT. The fabrication process is also simple with efficient utilization of the sensor’s sensitive region. The CSRR is excited uniquely through a transmission line with periodically placed capacitive gaps in series. By placing the capacitive gaps, effective negative permeability and permittivity are simultaneously achieved, and the structure exhibits metamaterial [composite right/left-handed transmission line (CRLH-TL)] left-handed behavior. Greater coupling of electromagnetic energy from the transmission line to the resonator is achieved by increasing the capacitive gap widths, which renders higher sensitivity. The main sensing parameter is the shift in the frequency of the transmission coefficient notch arising due to the placement of chemicals of varying concentrations throughout the ring region in the hollow tube. The sensor dimension is 4 cm (0.012 $\lambda {g}$) $\times $ 4 cm (0.012 $\lambda {g}$), with $\lambda {g}$ being the guide wavelength. The large sensing bandwidth obtained is 1320 MHz that corresponds to high sensitivity of 14.66 MHz/unit change in concentration and 21.44 MHz/unit change in permittivity. The sensor is cheap and small, and the sensing process is simple offering instantaneous results. [ABSTRACT FROM AUTHOR]

During the process of gas production in high-pressure, high-temperature (HPHT) gas wells, the choke valve, as the most vital component of the surface control equipment, plays a significant role in regulating the output and reducing the fluid pressure to ensure the safety of surface gathering and transportation equipment. High-pressure, high-velocity fluid flow and solid-phase particles cause deterioration of the choke valve. With the enhancement of intelligent and digital oilfields, conventional choke valves have been progressively replaced by electric choke valves. Due to the complex structure of the throttle valve, the flow path and the velocity state of the fluid in the throttle valve, and the distribution law of the erosion fraction are quite distinctive from those in the ordinary throttle valve, meriting further research. In this paper, a simulation of computational fluid dynamics (CFD) was conducted to determine the effects of the pressure distribution, fluid state, divergent particle sizes, and sand volume on the erosion rate of the choke valve. Under various valve openings, the fluid state and the location of high-risk points can be ascertained. The large particle size (diameter greater than 6 mm) of sand and gravel is convenient for causing concentrated erosion in the position of the valve hole, which induces the channel diameter to expand. Fine silt sand (diameter from 0.1 mm to 1 mm) gives rise to relatively uniform abrasion to the choke's current-facing surface. This study can optimize the layout of the choke valve and reduce the cost and number of switching wells, thereby decreasing the frequency of maintenance and the pressure fluctuation's effect on the formation. [ABSTRACT FROM AUTHOR]