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Copyright of Erzincan University Journal of Science & Technology is the property of Erzincan Binali Yildirim Universitesi 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 article evaluates several products, including the E-Xtreme rectangular enclosures by Mencom, which provide protection for electrical components in harsh industrial environments with anti-corrosion aluminum and patented titanium-plasma coating; the Rack Fire Protect (RFP) buildings by DENIOS.

Copyright of International Journal of Engineering Research & Development (IJERAD) is the property of International Journal of Engineering Research & Development 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 article explores the scientific validity of the belief that coconut water has miraculous properties for pregnancy-related issues. It discusses the composition of coconut water, which includes glucose, protein, inorganic ions, sugar alcohols, essential amino acids, and fatty acids. Research suggests that coconut water may have beneficial effects on oral rehydration, hypertension, diabetes, morning sickness, and labor progression. While some cultural beliefs may exaggerate the benefits of coconut water, there is scientific evidence to support its use in certain pregnancy-related situations. [Extracted from the article]

Background: Meconium staining of amniotic fluid harms newborns. Pregnant women in Palangka Raya City have the habit of consuming young coconut water to prevent the meconium staining of amniotic fluid. Young coconut water contains the highest mineral potassium. Potassium can affect the intestinal peristaltic. Objective: Analyzing the effect of potassium of young coconut water consumed by pregnant women in the third trimester on the levels of potassium saliva of mothers and the newborn and meconium levels of amniotic fluid. Methods: This study was a prospective cohort study of third-trimester pregnant women. The study sample was taken randomly, 24 pregnant women who consumed young coconut water and 24 who did not consume young coconut water. Results: Potassium levels of young coconut water had a positive correlation with levels of maternal salivary potassium (b = 0,414, p = 0,000). Maternal salivary potassium levels had a negative correlation with meconium levels of amniotic fluid (b = -0,603, p = 0,000). Maternal salivary potassium levels through infant salivary potassium levels had a negative correlation with meconium levels of amniotic fluid (b= -0,205, p = 0,000). Conclusion: Young coconut water consumed by pregnant women during the third trimester can prevent the meconium staining of amniotic fluid [ABSTRACT FROM AUTHOR]

This article comprises of modeling, design, and analytical results of conventional and advanced controllers like P, PI, PID, and MPC algorithm for nonlinear tank system are considered to achieve desired set point tracking in level measurement. Hopper shape tank system is considered as non-linear, which comprises of numerous influence variables (output, manipulated, and input variables). Most of the processes used in the petrochemical, process, and pharmaceutical industries are non-linear. Due to the nonlinear cross-section at the hopper tank, measurement of level plays a vital role in these industries. The authors have designed four different controllers for desired level tracking and simulated in MATLAB software to achieve the closed-loop and open-loop performance analysis of the processing system. Autotune and Ziegler Nicholas method based PID algorithm has been used by some authors to find the tuning parameters of P, PI, and PID Controllers for achieving the desired set point. MATLAB Simulink model is used for the design and implementation of the controllers for a nonlinear process tank system and to obtain the rise time, overshoot, settling time, and steady-state error that indicates the performance of the process with the controller. The advanced control algorithms like MPC with linear constraints is designed for level tracking of hoper tank system within desired specified limits. Finally, the performance analysis is compared with conventional controllers like P, PI, and PID. MPC with linear constraints will be able to track the level of the hoper tank system in less time and a reduced number of control and prediction horizons. [ABSTRACT FROM AUTHOR]

We have studied the effect of transient vibrational inversion of population in trans-β-apo-8'-carotenal on the time-resolved femtosecond stimulated Raman scattering (TR-FSRS) signal. The experimental data are interpreted by applying a quantum mechanical approach, using the formalism of projection operators for constructing the theoretical model of TR-FSRS. Within this theoretical frame we explain the presence of transient Raman losses on the Stokes side of the TR-FSRS spectrum as the effect of vibrational inversion of population. In view of the obtained experimental and theoretical results, we conclude that the excited S2 electronic level of trans-β-apo-8'-carotenal relaxes towards the S0 ground state through a set of four vibrational sublevels of S1 state. [ABSTRACT FROM AUTHOR]

The extraction of sucrose in a cane diffuser depends mainly on the percolation rate, and its optimisation requires the monitoring and control of the liquid holdup with the cane bed. However, most conventional methods that measure liquid levels are not suitable for this application. Operators control the observed liquid level through diffusers' sight glasses, adjusting the spray position according to visual inspections. The method is inefficient, and a more accurate and reliable measurement process should be implemented towards maximising the sucrose extraction. This article proposes a novel methodology that uses conductance measurements as indicators of the liquid level in cane beds. Conductance, observed liquid level and flow rate variations were analysed under several conditions, such as steady and unsteady states. The effects of the main variables on the observed liquid level and their mathematical relationship were assessed for the validation of the measurements, and experimental tests were conducted on a BMA cane diffuser at Maidstone factory in South Africa. The results are reproducible and show conductance can qualitatively characterise a flooded cane bed. [ABSTRACT FROM AUTHOR]

Aims and Objectives: To ascertain norms in cephalometry for 11- to 13-yearold Lingayat children in natural head position (NHP). Materials and Methods: Lateral cephalograms of children were obtained by using fluid level device. We determined the variance in Frankfort horizontal plane (FHP) inclination to extracranial horizontal in NHP. The G*Power, version 20 for Windows was used for analysis. Results: Reduced facial convexity was observed when the analysis was carried out in relation to true horizontal with significant difference of "t" value of 3.05 and percentage difference of 1.1 (P < 0.01) and for girls "t" value of 9.69 and percentage difference of 2.5 (P < 0.001). The highest correlation coefficient for Lingayat boys (r = 0.77) was seen between palatal plane and occlusal plane. We found least correlation coefficient among FHP and Sella-nasion plane (SNP). The coefficient was r = 0.62 and correlation coefficient of r = 0.70 was between FHP and determination coefficient r2 = 0.38 or 38%. For girls, highest correlation coefficient of r = 0.70 was seen among FHP and palatal plane. Conclusion: Conventional study of craniofacial forms of Lingayat children showed the average skeletal pattern as Class II with retrognathic mandible in comparison to Caucasians. However, when seen in NHP by new method of analysis based on the true horizontal, the skeletal model was Class III in comparison to Caucasians. [ABSTRACT FROM AUTHOR]

Highlights • New method to detect liquid level using fiber bundle. • The sensor mechanism is simple which is based on hydrostatics pressure principle. • Results show that working area of sensor is more than 100 cm. Abstract Liquid level sensors can be constructed using a pair of bundle probe based on fiber-optic displacement sensor. The working mechanism of the sensor is detecting displacement in the reflector which is attached to membrane (reflector displacement device or RDD) due to changes in the level of the liquid. Displacement of reflector is detected through changes in the intensity of reflected light from reflector into an optical fiber that serves as the recipient of the light. Other optical fiber acts as a transmitter of light. Three types of RDD was used in this experiment, namely RDD consisting of 1, 2, and 3 layers of the membrane. The best performance is shown by the sensor using RDD with 1 layer membrane. Sensor range, linear region, sensitivity, and resolution sensor generated each of 115 cm, 110 cm, 0.37 mV/cm, and 1.45 cm. [ABSTRACT FROM AUTHOR]

The dynamic liquid level of an oil well can be used to determine the oil production strategies and analyze the reservoir performance. Therefore, it is important to measure the dynamic liquid level in an oil field. This paper proposes a novel dynamic liquid level measurement method for oil wells, where the resonant frequency difference (RFD) of the resonant acoustic signal in annular is used to calculate the dynamic liquid level. To solve the noise interference problem in the resonant acoustic signal, a spectral fast Fourier transform (FFT) method based on Welch power spectrum is proposed to obtain the RFD. First, the Welch power spectrum approach is employed to process the resonant acoustic signal, and a high-pass filter is designed to filter the inherent envelope of low frequency in the power spectrum. In particular, a clear and smooth power spectrum can be obtained by choosing a suitable window and a sectional length. Furthermore, the short-time Fourier transform method is used to extract the strongest energy spectrum of the power spectrum. Finally, the RFD of two adjacent resonant harmonics can be accurately obtained by using FFT for the strongest energy spectrum. Experimental results show the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Highlights • A highly sensitive liquid level monitoring based on discrete wavelength sampling method is proposed and demonstrated. • The proposed method can archive the highly sensitive resolution of 0.5 mm and the large measurement range of 50 cm. • It is the first time to apply wavelength sampling method to liquid level measurement based on SNS structure. • The sensor has the ability to discriminate different RI of liquid. Abstract The liquid level fiber sensor with a measurement range of about 50 cm is fabricated through a kind of single-no-core-single mode (SNS) structure. It is found that the change of liquid level will only induce the wavelength shifts of the whole interference spectrum. The liquid level monitoring with sub-millimeter resolution can be achieved by the proposed discrete wavelength sampling method. In the experiment, the transmit interference spectrum is sampled by a tunable laser with a step of 0.5 nm, then constructed by cubic spline interpolation algorithm. The wavelength shifts can be obtained through a minimum variance demodulation algorithm. Experiment results exhibit an excellent linear response (R2 = 0.99993) and the high sensitivity response to different liquid refractive index (RI). And the sensitivity of the sensor is 23.38 pm/mm with the liquid RI of 1.3505. In particular, the sensing resolution of the liquid level can reach 0.5 mm. This anti-electromagnetic interference technique with such high resolution and large sensing range can find the promising applications of monitoring the left fuel in the aircraft tanker, the surface evaporation in the water resource cycle, etc. [ABSTRACT FROM AUTHOR]

The physical mechanism underlying the effect of generation of Auger duplexes as a consequence of the electronic level transformation in the case of local energetic effect in the atoms of complex oxides is suggested. It has been established that the effect of the formation of Auger duplexes is independent of the type of radiation acting on an object and is determined by the energy of the affecting particles and by the time of irradiation leading to accumulation of the reactions induced by electrons (ions). [ABSTRACT FROM AUTHOR]

Highlights • New design of liquid level sensor using two fiber bundle simultaneously. • Based on displacement sensor, the detection mechanism utilizes hydrostatic pressure. • The two-tier liquid level detection principle produces a working area of 130 cm. Abstract The two-tier detection of liquid level using two fiber bundles as sensor has been successfully demonstrated. Each fiber bundle is paired with a reflector displacement device (RDD) to detect liquid level in accordance with its detection area. Based on displacement sensor, the working principle of system is by utilizing hydrostatic pressure to shift the reflector attached to the membrane. Detection of liquid level is done through changes of reflected light intensity from the reflector that goes into each sensor probe. The results show that the sensor can be applied to the front slope or back slope area. Working area and resolution of sensors working on the front slope area are 0–130 cm and 1 cm, meanwhile for the back slope area are 0–50 cm and 0.1 cm. [ABSTRACT FROM AUTHOR]

Abstract: Detection liquid level using fiber coupler, a pair, and concentric bundled probes has been demonstrated. The detection mechanism is based on displacement sensor and utilizing the principle of hydrostatic pressure. The results indicate that the concentric bundled probe has the best performance with a sensor range of 130 cm. [ABSTRACT FROM AUTHOR]

Mainstreams in research on measurement systems for cryogenic process monitoring are reviewed with the aim of defining key current trends and possible future evolutions. At this aim, research mainstreams are classified according to the measurand: liquid level, flow rate, and pressure. In these fields, research on innovative measurement systems is surveyed, by highlighting main basic ideas, original design solutions, main results, and positioning in the innovation landscape. Then, current and future research trends are outlined in order to draw evolution scenarios of measurement systems for cryogenics monitoring. [ABSTRACT FROM AUTHOR]

This article presents results of tests of the effect exerted by technical condition of shock absorbers on the braking efficiency of an automotive vehicle. The tests were conducted using Fiat Seicento featuring front shock absorbers which enabled shock-absorbing fluid-level adjustment. The tests comprised measurements conducted on the shock absorbers in four states, i.e. the nominal state with the fluid level at 100%, with shock-absorbing fluid levels of 25%, 50% and 75% as well as with the fluid tank completely empty (0%). Road tests of braking efficiency were conducted on cobbled pavement by means of a decelerometer. [ABSTRACT FROM AUTHOR]

This paper describes a new method and control process for an optical headlight design. A series of experiments were conducted to demonstrate the projection angle of headlights using this method. In addition, the dynamic model of the headlight control system was discussed. Several parameters were considered, including the uphill and downhill road conditions and vehicle speed, to understand the multistage variations of the new headlight control system. The vehicle conditions were monitored by a vehicle speed sensor and electronic level. The variations of the projection angle of the headlight system were simultaneously controlled during the work process. This study helps in the development of a new headlight system that could be promoted to improve the projection and visibility under different uphill and downhill road conditions and vehicle speed, resulting in improved driving safety. The new system could be useful for application in different front‐lighting (low-beam, high-beam) and fog light systems. The control unit comprised a control box and electronic level, which could be modified to allow parameter setting under different operating and functional requirements, resulting in the system having broad application in different vehicles. This new method could decrease the problem of a driver in against the side of a vehicle when the vehicle passes another one, resulting in the prevention of traffic accidents. [ABSTRACT FROM AUTHOR]

Liquid level control value is widely used in the process industry to control internal liquid height as pipe flow control component. During the operation of the liquid level control valve, the force condition of the value core directly affects the stability of the valve works. Therefore, it becomes the important factors in the design of the spring components of the liquid level control valve. In this paper, the internal flow field of the automatic control valve during closing process is simulated by using Fluent CFD software. The numerical simulation results show that in the process of closing the automatic control value, the water hammer phenomenon will be occurred at the beginning stage. With the continuation of the valve closing process, the pressure in upper chamber of the value core and internal chamber are rapidly reduced and tend to be gentle, while the pressure difference increases gradually. What is more, the flow of throttle gradually increases, and the inner chamber of the valve core appears small disturbance. These conclusions provide a theoretical basis for the technical design and improvement of the control valve. [ABSTRACT FROM AUTHOR]

At present, all kinds of liquid level control system is widely used in ground and underground storage tanks and other containers, which plays an important role to ensure the safety of production. Thus, it become an indispensable device of modern oil production and storage. In this paper, the governing equations of the internal flow field of the automatic control valve are established by using the basic theory of computational dynamic fluid and the RNG two equations turbulence model. And, the internal flow field of the automatic control valve under steady working state is simulated by using Fluent CFD software. Then, the pressure diagram, velocity profiles figure, velocity vector diagrams were obtained. It is believed that the research results of this paper have reference value for the further optimization of liquid level control valve. [ABSTRACT FROM AUTHOR]

The liquid level control is essential in many production installations but the classic approaches often fail to ensure the desired performance. The reasons are the plant nonlinearity, the level oscillations and the plant model uncertainties. The aim of the present investigation is to improve the existing linear control of the level in the carbonization columns for soda ash production by employing fuzzy logic using parallel distributed compensation (PDC). The design of the PDC is based on a nonlinear Takagi–Sugeno–Kang (TSK) plant model which is derived via genetic algorithms optimization and validated using the data from the real time linear level control. The PDC control performs soft blending of the outputs of several parallel local linear controllers each developed for the local linear plant of the TSK model. The fuzzy rules are represented by ordinary logics conditions to enable the PDC programming and use by an industrial programmable logic controller. The PDC increases the dynamic accuracy in the level control and reduces the frequency of the control oscillations compared to the previous linear control thus prolonging the lifetime of the expensive pneumatic actuators used. [ABSTRACT FROM AUTHOR]

An optical fiber liquid level sensor based on two twisted polymer optical fibers twining around a racetrack column is demonstrated in this study. The side-coupling power of the passive fiber is modulated by the refractive index (RI) of the environment medium and decreases while the liquid level increases. The variation patterns of the side-coupling power in the bent section and the straight section form a step attenuation, which can improve the measurement range with a superior sensitivity and distinguish liquids with different RIs. Furthermore, the cost-effective sensor also shows good reversibility and low temperature-dependent properties. [ABSTRACT FROM AUTHOR]

Abstract: A recent analytical model predicts free, entrapped, and residual LNAPL saturations and the LNAPL transmissivity in the subsurface from current and historic fluid levels in groundwater wells. As such, the model accounts for effects of fluid level fluctuations in a well. The model was developed to predict LNAPL specific volumes and transmissivities from current fluid level measurements in wells and either recorded historic fluid level fluctuations in wells or estimates. An assumption is made in the model that the predictions are not dependent on whether the historic highest or lowest fluid level elevations in a well occur first. To test the assumption, we conduct two simulations with a modified multiphase flow numerical code TMVOC that incorporates relative permeability‐saturation‐capillary head relations employed in the model. In one simulation, the initial condition is for fluid levels in a well at the historic highest elevations. In the other simulation, the initial condition is for fluid levels in a well at the historic lowest elevations. We change the boundary conditions so both historical conditions occur followed by generating the current condition. Results from the numerical simulations are compared to model predictions and show the assumption in the analytical model is reasonable. The analytical model can be used to develop/refine conceptual site models and for assessing potential LNAPL recovery endpoints, especially on sites with fluctuating fluid levels in wells. [ABSTRACT FROM AUTHOR]

We re-examine the physics of supercritical nuclei, specially focusing on the scattering phase $$\delta _{\varkappa }$$ and its dependence on the energy $$\varepsilon $$ of the diving electronic level, for which we give both exact and approximate formulas. The Coulomb potential $$Z\alpha /r$$ is rounded to the constant $$Z\alpha /R$$ for $$r < R$$ . We confirm the resonant behavior of $$\delta _{\varkappa }$$ that we investigate in detail. In addition to solving the Dirac equation for an electron, we solve it for a positron, in the field of the same nucleus. This clarifies the interpretation of the resonances. Our results are compared with claims made in previous works. [ABSTRACT FROM AUTHOR]

By simulating the sound field of a round piston transducer with the Kirchhoff integral theorem and analyzing the shape of ultrasound beams and propagation characteristics in a metal container wall, this study presents a model for calculating the echo sound pressure by using the Kirchhoff paraxial approximation theory, based on which and according to different ultrasonic impedance between gas and liquid media, a method for detecting the liquid level from outside of sealed containers is proposed. Then, the proposed method is evaluated through two groups of experiments. In the first group, three kinds of liquid media with different ultrasonic impedance are used as detected objects; the echo sound pressure is calculated by using the proposed model under conditions of four sets of different wall thicknesses. The changing characteristics of the echo sound pressure in the entire detection process are analyzed, and the effects of different ultrasonic impedance of liquids on the echo sound pressure are compared. In the second group, taking water as an example, two transducers with different radii are selected to measure the liquid level under four sets of wall thickness. Combining with sound field characteristics, the influence of different size transducers on the pressure calculation and detection resolution are discussed and analyzed. Finally, the experimental results indicate that measurement uncertainly is better than ±5 mm, which meets the industrial inspection requirements. [ABSTRACT FROM AUTHOR]

Recently, steam assisted gravity drainage (SAGD) has been widely adopted in thermal recovery for heavy oil. However, challenges remain in SAGD development: the close distance between injector and producer makes it easy to cause steam breakthrough, which means lower thermal efficiency as well as higher investment. It is generally acknowledged that there is a liquid level existing between the injector and producer, a reasonable liquid level could prevent steam from being produced directly. The existence of liquid level generates a temperature difference between two wells, i.e., subcool. Subcool has generally been used to describe liquid level in practice and in many researches, yet it is inaccurate. In order to characterize the liquid level precisely, it is necessary to fully clarify the relationship among subcool, liquid level and pressure difference between injector and producer. By analyzing the features of subcool and pressure difference shown in SAGD experiments, it is found that the value of subcool may be not directly relevant with the distance between injector and producer, considering the huge difference between experiments and the measured data from actual oilfield. Correspondingly, liquid level is supposed to be treated as a dimensionless variable, to be specific, named as dimensionless liquid level, defined as liquid level divided by the distance between two wells. Afterwards, over 40 cases of CMG numerical simulations are run to investigate the liquid levels with different injector-producer distances and different subcools. Based on the analysis of simulation results, the dimensionless liquid level increases with subcool, while for a given subcool, dimensionless liquid level is inversely proportional to pressure difference between injector and producer. Accordingly, liquid level could be accurately controlled under a given subcool and pressure gradient, which is applicable and be of great significance for the SAGD operation on the field. [ABSTRACT FROM AUTHOR]

The extraction of molten iron and slag in the liquid phase from the lower part of a blast furnace (hearth) is usually accomplished according to operational experience and involves a high degree of uncertainty, mainly because the liquid level cannot be directly measured. This study presents a methodology for obtaining multistep models to forecast the hearth liquid level by measuring a voltage generated on the blast furnace shell, which is strongly correlated with the hearth liquid level. The results show that this electrical signal is a nonstationary and nonlinear time-series that, after appropriate treatment, can be represented by a time-delay neural network (TDNN) model. Some comparisons are made with linear time-series models represented by an autoregressive moving average model and a seasonal autoregressive integrated moving average model, and the results indicate that the TDNN model provides better forecasting performance up to one hour ahead. [ABSTRACT FROM AUTHOR]

A new controller based on discrete wavelet packet transform (DWPT) for liquid level system (LLS) has been presented here. In this proposed controller, packet transform is used to decompose the error signal into different frequency nodes at various scales which represents many underlying phenomena such as process dynamics, noise and disturbances. These coefficients are scaled by their respective gains and then added together to generate the control signal. NI DAQ device is used to interface between the PC based controllers simulated in NI LABVIEW software to the real time RC plant analogous to LLS and a second order RLC plant. The performance of this controller has been studied and compared to the PI controller. From hardware results, this controller is shown to perform better than both the discrete wavelet transform (DWT) based proportional integral controller and PI controller. Also, it can handle noise more efficiently. [ABSTRACT FROM AUTHOR]

Objective: The aim of our study was to investigate morphological differences in the upper airway of healthy men and women on lateral cephalometric radiographs. Material-Method: In our study, we evaluated 76 lateral cephalometric radiographs of adult subjects (38 men and 38 women) with class I skeletal pattern taken in natural head posture. In order to determine natural head posture, we used self-balance position, which was transferred to the cephalostat by means of a fluid level device. All lateral cephalograms were traced manually. The effect of gender on upper airway morphology and natural head posture was evaluated using Student's t-test. Results: We found that measurements used in the determination of natural head posture were similar for men and women. Linear measurements regarding the position of bony structures (MP-AH, AH-AH1, C3ia-AH, and Ba-C3ia), soft tissue (PNS-P, MPT, PNS-Et, TGL, and TGH), tongue area, soft palate area, and oropharynx area were statistically significant, with respect to gender. Conclusions: The hyocervical relation is affected by gender differences whereas hyomandibular relation is well balanced in subjects with normal occlusion and class I skeletal pattern and was not affected by gender. Natural head posture was not affected by gender differences. Tongue area, soft palate area, and oropharyx area are larger in men. However, no statistically significant differences were observed between genders for nasopharynx and hypopharyx areas. [ABSTRACT FROM AUTHOR]

The proposed method for measuring the liquid level focuses on the ultrasonic impedance and echo energy inside a metal wall, to which the sensor is attached directly, not on ultrasonic waves that penetrate the gas-liquid medium of a container. Firstly, by analyzing the sound field distribution characteristics of the sensor in a metal wall, this paper proposes the concept of an "energy circle" and discusses how to calculate echo energy under three different states in detail. Meanwhile, an ultrasonic transmitting and receiving circuit is designed to convert the echo energy inside the energy circle into its equivalent electric power. Secondly, in order to find the two critical states of the energy circle in the process of liquid level detection, a program is designed to help with calculating two critical positions automatically. Finally, the proposed method is evaluated through a series of experiments, and the experimental results indicate that the proposed method is effective and accurate in calibration of the liquid level outside a sealed metal container. [ABSTRACT FROM AUTHOR]

A model of measuring the level of a viscous incompressible liquid in a tank as based on the liquid level in a measuring tube is investigated. The tank is in the field of gravity, and the tank liquid level varies according to some law. As a result, a Dirichlet boundary value problem for a nonlinear integrodifferential equation of parabolic type is obtained. A global existence and uniqueness theorem is proved for a weak solution of the problem. In the case of a tank level decreasing linearly with time, it is shown numerically that the liquid level in the measuring tube oscillates with a decaying amplitude with respect to the tank level. [ABSTRACT FROM AUTHOR]

Liquid level in coupled tanks is difficult to control by classical techniques because the plant is nonlinear, multivariable, often with no self-regulation and no model. Fuzzy logic (FL) enables a successful stable and robust control by simple means and a model-free design. This paper suggests a procedure for the design of two-variable FL controllers (FLCs) for the levels in a laboratory coupled-tank system. First a model-free two-variable Mamdani FLC is empirically developed and applied for real-time levels control. The plant input and output experimental data are then used for derivation via genetic algorithms optimization of a Takagi–Sugeno–Kang (TSK) plant model needed for FLC improvement. The TSK model is validated on a different set of experimental data and used in designing of two-variable linear proportional-plus-integral (PI) controller and parallel distributed compensation with local linear PI controllers. The performance of the systems with the designed controllers is compared in real-time levels control. [ABSTRACT FROM AUTHOR]

The macro-bending induced optical fiber cladding modes frustrated total internal reflection effect is used to realize the liquid level probe with a simple structure of single macro-bend polymer optical fiber loop. The test results show that the extinction ratio reaches 1.06 dB. 'First bath' phenomenon is not obvious (about 0.8%). The robustness of the sensor is better, and the ability of anti-pollution is stronger compared with the conventional sensors. The process of making this sensing probe is extremely easy, and the cost is very low. [ABSTRACT FROM AUTHOR]