Siga este enlace para ver otros tipos de publicaciones sobre el tema: RDF Saturation.
Artículos de revistas sobre el tema "RDF Saturation"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores artículos de revistas para su investigación sobre el tema "RDF Saturation".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore artículos de revistas sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Pandeline, Deborah A., Paul J. Cosentino, Edward H. Kalajian y Mario F. Chavez. "Shear and Deformation Characteristics of Municipal Waste Combustor Bottom Ash for Highway Applications". Transportation Research Record: Journal of the Transportation Research Board 1577, n.º 1 (enero de 1997): 101–8. http://dx.doi.org/10.3141/1577-13.
Texto completoResumen
Municipal waste combustor (MWC) bottom ash from mass-burn (MB) and refuse-derived-fuel (RDF) facilities was evaluated for potential use as highway fill material. MWC bottom ash exhibits acceptable shear and deformation characteristics for many highway applications. RDF ash contains a lower metals percentage than MB ash. The specific gravity of both ashes was found to be a function of metals content. Moisturedensity relationships and unconfined compressive strengths were found to be a function of compaction energy and moisture content. Allowing compacted ash to age increased its unconfined compressive strength. Stress-strain characteristics of both ashes are similar to those of sands. Cohesion exists possibly because of pozzolonic reactions in the bottom ash. The angle of internal friction increased with compacted density. Elastic moduli are a function of density and confining pressure. RDF ash was found to be twice as stiff as MB ash. California bearing ratio results greater than 100 indicated that MB ash could be utilized as road base, and values between 25 and 95 indicated that RDF would be acceptable for use in subgrade and subbase. Bearing ratio results were highly dependent on moisture conditions. Both ashes exhibit little to no swell and should not cause field problems during saturation.
2
Zamora, Jonathan, Israel Betancourt y José Alejandro García Hinojosa. "The Influence of Boron on Microstructural Evolution, Mechanical and Magnetic Behavior of Amorphous Fe91−x(Zr5-Nb4)Bx Melt-Spun Alloys". Metals 12, n.º 6 (10 de junio de 2022): 994. http://dx.doi.org/10.3390/met12060994.
Texto completoResumen
In this work, we report a systematic study on the microstructure evolution of rapid solidified Fe91−xZr5Nb4Bx alloys (x = 10, 15, 20, 25, 30 at%) under melt-spinning conditions. Mechanical and magnetic properties are also evaluated. X-ray diffraction patterns indicate that the microstructure across the compositional series consists of an amorphous matrix with partial crystallization when boron concentration is increased. These features were identified by transmission electron microscopy (TEM). The radial distribution function (RDF) affords to resolve the nearest-neighbor configuration. The tensile and microhardness properties were measured to correlate the microstructural evolution with boron content. On the other hand, the magnetic properties of these alloy series were determined by vibrating sample magnetometry (VSM); the saturation magnetization and Curie temperature showed an increasing tendency when increasing the boron content, reaching values up to 110 Am2kg−1 and 465 K, respectively. In addition to the aforementioned, the coercive field remained constant. All these magnetic properties were correlated with the microstructure features observed by XRD, RDF and TEM.
3
Krishtal, S., M. Kiselev, Y. Puhovski, T. Kerdcharoen, S. Hannongbua y K. Heinzinger. "Study of the Hydrogen Bond Network in sub-and supercritical Water by Molecular Dynamics Simulations". Zeitschrift für Naturforschung A 56, n.º 8 (1 de agosto de 2001): 579–84. http://dx.doi.org/10.1515/zna-2001-0807.
Texto completoResumen
Abstract For 12 points along the tangent to the saturation curve at the critical point the temperature dependencies of the heights of the first maximum in the 0 -0 RDF, the average number of hydrogen bonds, and the self-diffusion coefficients have been calculated from MD simulations. The curves of these three properties show an inflection near the critical point. To improve the understanding of these changes in going from subcritical to supercritical water the librational spectra and the change in the fractions of water molecules with a given number of hydrogen bonds as a function of temperature have been derived from the simulations, additionally.
4
Choi, Yejoo, Jinwoong Lee, Jaehyuk Lim, Seungjun Moon y Changhwan Shin. "Impact of Process-Induced Variations on Negative Capacitance Junctionless Nanowire FET". Electronics 10, n.º 16 (7 de agosto de 2021): 1899. http://dx.doi.org/10.3390/electronics10161899.
Texto completoResumen
In this study, the impact of the negative capacitance (NC) effect on process-induced variations, such as work function variation (WFV), random dopant fluctuation (RDF), and line edge roughness (LER), was investigated and compared to those of the baseline junctionless nanowire FET (JL-NWFET) in both linear (Vds = 0.05 V) and saturation (Vds = 0.5 V) modes. Sentaurus TCAD and MATLAB were used for the simulation of the baseline JL-NWFET and negative capacitance JL-NWFET (NC-JL-NWFET). Owing to the NC effect, the NC-JL-NWFET showed less variation in terms of device performance, such as σ[Vt], σ[SS], σ[Ion/Ioff], σ[Vt]/µ[Vt], σ[SS]/µ[SS], and σ[Ion/Ioff]/µ[Ion/Ioff], and enhanced device performance, which implies that the NC effect can successfully control the variation-induced degradation.
5
Yadav, O. S., Sanjay Swami y T. V. Sowjanya. "Impact of biochar on nutrient uptake by tomato, residual soil properties and acidity indices in acid Inceptisol of Meghalaya". Journal of Environmental Biology 41, n.º 6 (15 de noviembre de 2020): 1761–73. http://dx.doi.org/10.22438/jeb/41/6/si-276.
Texto completoResumen
Aim: To investigate the impact of biochar as component of integrated nutrient management on nutrient uptake by tomato in acid soil of Meghalaya, North East India. Methodology: A field experiment was conducted at research farm of SNRM, College of Post Graduate Studies in Agricultural Sciences (CPGS-AS), Central Agricultural University (CAU-I), Umiam during rabi 2017-18 taking tomato, cv. Megha Tomato-2 as test crop. Sixteen treatment combinations of recommended closes of fertilizers, biochar and vermicompost? were tested in RBD with three replications.? Results: The experimental results revealed that combined application of biochar, fertilizers and vermicompost increased the uptake and availableof N, P, K, Fe, Zn, Mn and Cu over graded doses of biochar + fertilizers, biochar alone and control. Electrical conductivity, bulk density, exchangeable acidity, exchangeable aluminium and acid saturation followed the same trend.? Interpretation: The 100% RDF + biochar 4 t ha-1 + vermicompost @ 2.5 t ha-1 is the most appropriate combination for increasing tomato productivity and improving soil health of acidic soil in Meghalaya.
6
Cao, Xinfang y Shuo Lu. "Molecular Dynamics Simulation of the Effects of Different Initial Water Content on Methane Hydrate Decomposition". Scientific and Social Research 5, n.º 12 (27 de diciembre de 2023): 60–65. http://dx.doi.org/10.26689/ssr.v5i11.5837.
Texto completoResumen
Gas hydrate is mainly distributed in deep sea-floor sediments and permafrost regions. The water content of these sediments varies with the type of reservoir and affects the rate of hydrate decomposition. In this work, the decomposition process of methane hydrate under four different initial water contents was investigated by molecular dynamics simulation. The results were analyzed by the system conformation, radial distribution function (RDF), and mean square displacement (MSD), which revealed the microscopic mechanism of the effect of the initial water content on the decomposition rate of hydrate. The results demonstrate that the hydrate decomposition starts from the boundary to the middle, and the cage structure is destroyed layer by layer. Methane molecules continue to escape from the hydrate cages as the hydrate decomposes, and subsequent decomposition of the hydrate is inhibited when its solubility in water reaches saturation. The higher the initial water content is, the faster the decomposition rate of hydrate is. The movement distance of methane gas is affected by the initial water content. The higher the initial water content, the smaller the MSD of methane molecules.
7
MAJID, DEWAN S. A., EDWARD W. INSCHO y L. GABRIEL NAVAR. "P2 Purinoceptor Saturation by Adenosine Triphosphate Impairs Renal Autoregulation in Dogs". Journal of the American Society of Nephrology 10, n.º 3 (marzo de 1999): 492–98. http://dx.doi.org/10.1681/asn.v103492.
Texto completoResumen
Abstract. Recent studies have suggested a role for P2 purinoceptors on vascular smooth muscle cells in the mechanism of renal autoregulation. Experiments were performed in anesthetized dogs (n = 9) to examine renal blood flow (RBF) auto-regulatory efficiency before and after saturation of P2 purinoceptors with acute intra-arterial administration of ATP (1 mg/kg per min). Dogs were pretreated with the nitric oxide synthase inhibitor nitro-L-arginine (NLA) (50 μg/kg per min), to avoid endothelial P2 receptor-mediated effects on nitric oxide release caused by the intra-arterial ATP infusions. NLA treatment decreased RBF (5.3 ± 0.3 to 3.6 ± 0.2 ml/min per g) and sodium excretion (3.6 ± 0.4 to 0.9 ± 0.2 ml/min per g) without producing significant changes in GFR (0.92 ± 0.04 to 0.90 ± 0.06 ml/min per g) or RBF autoregulatory efficiency. ATP administration to NLA-treated dogs resulted in further decreases in RBF (2.8 ± 0.2 ml/min per g), GFR (0.58 ± 0.05 ml/min per g), and sodium excretion (0.6 ± 0.2 μmol/min per g). In addition, there was marked impairment of RBF autoregulatory efficiency during ATP infusion. The slopes of the arterial pressure-blood flow relationships at renal arterial pressures of >75 mmHg were significantly altered, from 0.003 ± 0.001 to 0.2 ± 0.002 ml/min per g per mmHg. Discontinuation of ATP infusion restored RBF autoregulatory efficiency. Norepinephrine (5 μg/kg per min) administration in these NLA-treated dogs decreased RBF (2.5 ± 0.3 ml/min per g; n = 4) to a similar extent, compared with ATP, but did not impair RBF autoregulation. These results support the hypothesis that P2 purinoceptors may be involved in mediating autoregulatory adjustments in renal vascular resistance.
8
Deng, Hua, Renqiang Wang, Jingdong Li, Dawei Chen, Jianming Sun, Yue Zhao y Jiabao Du. "RBF Neural Network Control for USV with Input Saturation". MATEC Web of Conferences 214 (2018): 03002. http://dx.doi.org/10.1051/matecconf/201821403002.
Texto completoResumen
Intelligent control for USV with input saturation based on RBF network was proposed. Firstly, sliding surfaces with integral were designed on the basis of the sliding mode variable structure control technology. Secondly, RBF network was applied to approximate compensate the input saturation of system, and which was optimized by Genetic Algorithms. Finally, the control algorithm for USV was deduced by backstepping method with Lyapunov theory on the basis of sliding mode control. Relevant simulations show the control method is available for USV motion control.
9
Lian, Xiaobin, Jiafu Liu, Chuang Wang, Tiger Yuan y Naigang Cui. "RBF network based adaptive sliding mode control for solar sails". Aircraft Engineering and Aerospace Technology 90, n.º 8 (5 de noviembre de 2018): 1180–91. http://dx.doi.org/10.1108/aeat-04-2017-0112.
Texto completoResumen
Purpose The purpose of this paper is to resolve complex nonlinear dynamical problems of the pitching axis of solar sail in body coordinate system compared with inertial coordinate system. And saturation condition of controlled torque of vane in the orbit with big eccentricity ration, uncertainty and external disturbance under complex space background are considered. Design/methodology/approach The pitch dynamics of the sailcraft in the prescribed elliptic earth orbits is established considering the torques by the control vanes, gravity gradient and offset between the center-of-mass (cm) and center-of-pressure (cp). The maximal torques afforded by the control vanes are numerically determined for the sailcraft at any position with any pitch angle, which will be used as the restriction of the attitude control torques. The finite/infinite time adaptive sliding mode saturation controller and Bang–Bang–Radial Basis Function (RBF) controller are designed for the sailcraft with restricted attitude control torques. The model uncertainty and the input error (the error between real input and ideal control law input) are solved using the RBF network. Findings The finite true anomaly adaptive sliding mode saturation controller performed better than the other two controllers by comparing the numerical results in the paper. The control torque saturation, the model uncertainty and the external disturbance were also effectively solved using the infinite and finite time adaptive sliding mode saturation controllers by analyzing the numerical simulations. The stabilization of the pitch motion was accomplished within half orbit period. Practical implications The complex accurate dynamics can be approximated using the RBF network. The controllers can be applied to stabilization of spacecraft attitude dynamics with uncertainties in complex space environment. Originality/value Advanced control method is used in this paper; saturation of controlled torque of vane is resolved when the orbit with big eccentricity ration is considered and uncertainty and external disturbance under complex space background are settled. Moreover, complex and accurate nonlinear dynamical model of pitching axis of solar sail in body coordinate system compared with inertial coordinate system is provided.
10
Sarrafan, Neda y Khoshnam Shojaei. "High-Gain Observer-Based Neural Adaptive Feedback Linearizing Control of a Team of Wheeled Mobile Robots". Robotica 38, n.º 1 (11 de abril de 2019): 69–87. http://dx.doi.org/10.1017/s026357471900047x.
Texto completoResumen
SummaryThis paper addresses the neural network (NN) output feedback formation tracking control of nonholonomic wheeled mobile robots (WMRs) with limited voltage input. A desired formation is achieved based on the leader–follower strategy utilizing hyperbolic tangent saturation functions to reduce the risk of actuator saturation. The controller is developed by incorporating the high-gain observer and radial basis function (RBF) NNs using the inverse dynamics control technique. The high-gain observer is introduced to estimate velocities of the followers. The RBF NN preserves the robustness of the proposed controller against uncertain nonlinearities. The adaptive laws are also combined by a robust control term to estimate the weights of RBF NN, approximation errors, and bounds of unknown time-variant environmental disturbances. A Lyapunov-based stability analysis proves that all signals of the closed-loop system are bounded, and tracking errors are uniformly ultimately bounded. Finally, some simulations are carried out to show the effectiveness of the proposed controller for a number of WMRs.
11
Wu, Gang y Ke Zhang. "A Novel Guidance Law for Intercepting a Highly Maneuvering Target". International Journal of Aerospace Engineering 2021 (10 de diciembre de 2021): 1–19. http://dx.doi.org/10.1155/2021/2326323.
Texto completoResumen
Given the resolution of the guidance for intercepting highly maneuvering targets, a novel finite-time convergent guidance law is proposed, which takes the following conditions into consideration, including the impact angle constraint, the guidance command input saturation constraint, and the autopilot second-order dynamic characteristics. Firstly, based on the nonsingular terminal sliding mode control theory, a finite-time convergent nonsingular terminal sliding mode surface is designed. On the back of the backstepping control method, the virtual control law appears. A nonlinear first-order filter is constructed so as to address the “differential expansion” problem in traditional backstepping control. By designing an adaptive auxiliary system, the guidance command input saturation problem is dealt with. The RBF neural network disturbance observer is used for estimating the unknown boundary external disturbances of the guidance system caused by the target acceleration. The parameters of the RBF neural network are adjusted online in real time, for the purpose of improving the estimation accuracy of the RBF neural network disturbance observer and accelerating its convergence characteristics. At the same time, an adaptive law is designed to compensate the estimation error of the RBF neural network disturbance observer. Then, the Lyapunov stability theory is used to prove the finite-time stability of the guidance law. Finally, numerical simulations verify the effectiveness and superiority of the proposed guidance law.
12
Chu, Zhenzhong, Yunsai Chen, Daqi Zhu y Mingjun Zhang. "Observer-based adaptive neural sliding mode trajectory tracking control for remotely operated vehicles with thruster constraints". Transactions of the Institute of Measurement and Control 43, n.º 13 (19 de abril de 2021): 2960–71. http://dx.doi.org/10.1177/01423312211004819.
Texto completoResumen
For a class of remotely operated vehicle (ROV) systems with thruster constraints, immeasurable states, and unknown nonlinearities, the trajectory tracking control problem was discussed in this paper. The unknown nonlinear functions were approximated by radial basis function (RBF) neural networks. An adaptive state observer based on neural networks was designed and the immeasurable states were estimated. Considering the problem of thruster saturation constraints, an auxiliary system for saturation compensation was designed and a saturation factor was constructed by the auxiliary system state. By applying the backstepping design method, an adaptive neural sliding mode trajectory tracking controller was developed, in which the saturation factor is contained in adaptive laws. It was proved that the uniformly ultimately bounded (UUB) of trajectory tracking errors can be obtained. Finally, the effectiveness of the proposed trajectory tracking control approach was checked by simulations.
13
Prasad, G. V. Ravi, Alexander Cherkinsky y Randy Culp. "Effect of Beam Transmission of Stable Isotopes on Online δ13C for SSAMS". Radiocarbon 61, n.º 5 (23 de julio de 2019): 1573–79. http://dx.doi.org/10.1017/rdc.2019.72.
Texto completoResumen
ABSTRACTIt is known that 12C beam transmission through the accelerator decreases at high beam currents. This effect depends on machine design and varies across different types of AMS instruments. For beam currents of about 100 μA, the effect is small on the 500 kV tandem CAMS unit, whereas beam saturation is observed for similar high beam currents on the 250 kV SSAMS unit. While this effect is very evident for high 12C beam currents, we have also observed that even the 13C beam is found to suffer modest transmission loss with beam current. As a result, the 13C/12C ratio does not remain constant with beam current. By correcting for the effects of 12C beam saturation and decreased 13C transmission, we have obtained online δ13C values that are more accurate and precise at moderately high beam currents for SSAMS.
14
Li, Jingdong, Dawei Chen, Jianming Sun, Keyin Miao y Renqiang Wang. "Intelligent control algorithm for USV with input saturation based on RBF network compensation". International Journal of Reasoning-based Intelligent Systems 11, n.º 3 (2019): 235. http://dx.doi.org/10.1504/ijris.2019.10023437.
Texto completo
15
Wang, Renqiang, Keyin Miao, Jianming Sun, Jingdong Li y Dawei Chen. "Intelligent control algorithm for USV with input saturation based on RBF network compensation". International Journal of Reasoning-based Intelligent Systems 11, n.º 3 (2019): 235. http://dx.doi.org/10.1504/ijris.2019.102562.
Texto completo
16
Kim, Sung-Jae y Jin-Ho Suh. "Adaptive Robust RBF-NN Nonsingular Terminal Sliding Mode Control Scheme for Application to Snake Robot’s Head for Image Stabilization". Applied Sciences 13, n.º 8 (13 de abril de 2023): 4899. http://dx.doi.org/10.3390/app13084899.
Texto completoResumen
Image stabilization is important for snake robots to be used as mobile robots. In this paper, we propose an adaptive robust RBF neural network nonsingular terminal sliding mode control to reduce swinging in the snake robot’s head while it is being driven. To avoid complex dynamic problems and reduce interference during driving, we propose a 2-DOF snake robot’s head system. We designed the control system based on the nonsingular terminal sliding mode control, which ensures a fast response and finite time convergence. To reduce chattering, we incorporated an RBF neural network that can compensate for disturbances. Additionally, we included an adaptive robust term to address the disadvantages of neural network-based control. The adaptive robust term generates control inputs based on the error and is used in conjunction with the reverse saturation function to eliminate chattering. The update law of the neural network and the adaptive robust term is designed based on Lyapunov’s theory. We proved the stability of the proposed controller by investigating finite time convergence before and after the reverse saturation function operation section. Finally, we verified the performance of the proposed controller through computer simulation. The simulation evaluates the controllers using a sinusoidal reference signal similar to snake robot movement and a mixed reference signal considering the controller’s waste case. The proposed controller has excellent tracking performance and improved chattering compared with the previous controller.
17
Wang, Changhui, Mei Liang y Yongsheng Chai. "Adaptive Neural Network Control of a Class of Fractional Order Uncertain Nonlinear MIMO Systems with Input Constraints". Complexity 2019 (28 de noviembre de 2019): 1–15. http://dx.doi.org/10.1155/2019/1410278.
Texto completoResumen
An adaptive backstepping control scheme for a class of incommensurate fractional order uncertain nonlinear multiple-input multiple-output (MIMO) systems subjected to constraints is discussed in this paper, which ensures the convergence of tracking errors even with dead-zone and saturation nonlinearities in the controller input. Combined with backstepping and adaptive technique, the unknown nonlinear uncertainties are approximated by the radial basis function neural network (RBF NN) in each step of the backstepping procedure. Frequency distributed model of a fractional integrator and Lyapunov stability theory are used for ensuring asymptotic stability of the overall closed-loop system under input dead-zone and saturation. Moreover, the parameter update laws with incommensurate fractional order are used in the controller to compensate unknown nonlinearities. Two simulation results are presented at the end to ensure the efficacy of the proposed scheme.
18
Taghipour Gorji, Reza, Seyyed Mehdi Hosseini, Ali Akbar Abdoos y Ali Ebadi. "A Hybrid Intelligent Method for Compensation of Current Transformers Saturation Based on PSO-SVR". Periodica Polytechnica Electrical Engineering and Computer Science 65, n.º 1 (25 de enero de 2021): 53–61. http://dx.doi.org/10.3311/ppee.16248.
Texto completoResumen
The Current Transformers (CT) saturation may cause the protective relays mal-operation either non-recognition of internal fault or undesirable trip under external fault conditions. Therefore, compensation of CT saturation is very important for correct performance of protective schemes. Compensation of CT saturation by combination of signal processing methods and intelligent algorithms is a suitable solution to solve the problem. It decreases the probability of mal-operation and increases the reliability of the power system. In this paper, Support Vector Regression (SVR) method is employed to compensate the distorted secondary current due to CT saturation. In SVR method, despite the other methods such as MLPand ANFIS, instead of minimizing the model error, the operational risk error is considered as target function. In this method, by using Kernel tricks, a smart RBF neural network is obtained, so that all operational procedures will be optimized automatically. In this paper, an intelligent method based on Particle Swarm Optimization (PSO) algorithm is presented to determine the optimal values of SVR parameters. Due to the stability and robustness of this method in presence of noise and sudden changes in current, this method has a high accuracy. In addition, a sample power system is simulated using PSCAD software. Afterwards, current signals are extracted and fed to PSO-SVR algorithm, which is implemented in MATLAB environment. The obtained results show the preference of the proposed method in aspect of estimation accuracy as compared to some presented methods in the field of CT saturation detection and correction.
19
Sadeghkhani, Iman, Abbas Ketabi y Rene Feuillet. "Radial Basis Function Neural Network Application to Measurement and Control of Shunt Reactor Overvoltages Based on Analytical Rules". Mathematical Problems in Engineering 2012 (2012): 1–14. http://dx.doi.org/10.1155/2012/647305.
Texto completoResumen
This paper presents an artificial intelligence application to measure switching overvoltages caused by shunt reactor energization by applying analytical rules. In a small power system that appears in an early stage of a black start of a power system, an overvoltage could be caused by core saturation on the energization of a reactor with residual flux. A radial basis function (RBF) neural network has been used to estimate the overvoltages due to reactor energization. Equivalent circuit parameters of network have been used as artificial neural network (ANN) inputs; thus, RBF neural network is applicable to every studied system. The developed ANN is trained with the worst case of the switching angle and remanent flux and tested for typical cases. The simulated results for a partial of 39-bus New England test system show that the proposed technique can measure the peak values and duration of switching overvoltages with good accuracy.
20
Yan, Maode, Jiacheng Song, Panpan Yang y Lei Zuo. "Neural Adaptive Sliding-Mode Control of a Bidirectional Vehicle Platoon with Velocity Constraints and Input Saturation". Complexity 2018 (2 de diciembre de 2018): 1–11. http://dx.doi.org/10.1155/2018/1696851.
Texto completoResumen
This paper investigates the vehicle platoon control problems with both velocity constraints and input saturation. Firstly, radial basis function neural networks (RBF NNs) are employed to approximate the unknown driving resistance of a vehicle’s dynamic model. Then, a bidirectional topology, where vehicles can only communicate with their direct preceding and following neighbors, is used to depict the relationship among the vehicles in the platoon. On this basis, a neural adaptive sliding-mode control algorithm with an anti-windup compensation technique is proposed to maintain the vehicle platoon with desired distance. Moreover, the string stability and the strong string stability of the whole vehicle platoon are proven through the stability theorem. Finally, numerical simulations verify the feasibility and effectiveness of the proposed control method.
21
Goergen, C., D. May y P. Mitschang. "Integration of rCF in resin transfer pressing process". Journal of Reinforced Plastics and Composites 39, n.º 9-10 (23 de febrero de 2020): 361–72. http://dx.doi.org/10.1177/0731684420906879.
Texto completoResumen
A new composite manufacturing process, resin transfer pressing, is introduced in this paper. In this process, nonwoven fabrics made of recycled carbon fibers are oversaturated with thermoset resin, i.e. they contain excess resin. The oversaturated nonwoven fabrics are prefabricated and used as resin carrier in a press process, where they are placed in a heated mold together with a dry textile-based preform. During pressing, the resin is pressed out and transferred from the nonwoven into the non-impregnated preform and hence impregnates the whole reinforcement. This study examines the oversaturation of nonwoven fabrics, the resin transfer pressing laminate manufacturing and the surface quality of the laminates. The ability of a nonwoven fabric to be oversaturated with resin is defined by the saturation degree, which was determined as up to 12 for glass fiber nonwoven fabrics and up to 60 for recycled carbon fiber nonwoven fabrics. Different laminates are manufactured by resin transfer pressing, and the impregnation quality is evaluated. With an optimized stacking sequence, a pore content <1% was achieved. The use of recycled carbon fiber nonwovens in the resin transfer pressing process leads to a less wavy surface compared to a wet compression molding manufactured laminate, showing a decrease of waviness Wz25 of 11% minimum.
22
Areni, Intan Sari, Indrabayu Amirullah y Nurhikma Arifin. "Klasifikasi Kematangan Stroberi Berbasis Segmentasi Warna dengan Metode HSV". Jurnal Penelitian Enjiniring 23, n.º 2 (30 de noviembre de 2019): 113–16. http://dx.doi.org/10.25042/jpe.112019.03.
Texto completoResumen
Classification of Strawberry Maturity Based on Color Segmentation using HSV Method. Manual fruit maturity classification has many limitations because it is influenced by human subjectivity. Hence, the application of digital image processing and artificial intelligence becomes more effective and efficient. This study aims to create a classification system that automatically divides strawberry maturity into three categories, namely not ripe, half-ripe, and ripe. The process of identifying the level of fruit maturity is based on the color characteristics Red, Green, Blue (RGB) value of the image. The method used for color segmentation is Hue, Saturation, Value (HSV) and for the classification of strawberry maturity using the Multi-Class Support Vector Machine (SVM) algorithm with a Radial Basic Function (RBF) kernel. Strawberry image data was retrieved using the Logitech C920 camera. The dataset consisted of 158 images of strawberries. The results showed that the classification of strawberry maturity using the multi-class SVM algorithm with kernel parameters RBF cost (C) = 10 and gamma (γ) = 10-3 produced the highest accuracy of 97%.
23
Hendrikx, Dries, Liesbeth Thewissen, Anne Smits, Gunnar Naulaers, Karel Allegaert, Sabine Van Huffel y Alexander Caicedo. "Using Graph Theory to Assess the Interaction between Cerebral Function, Brain Hemodynamics, and Systemic Variables in Premature Infants". Complexity 2018 (9 de agosto de 2018): 1–15. http://dx.doi.org/10.1155/2018/6504039.
Texto completoResumen
Graphs can be used to describe a great variety of real-world situations and have therefore been used extensively in different fields. In the present analysis, we use graphs to study the interaction between cerebral function, brain hemodynamics, and systemic variables in premature neonates. We used data from a propofol dose-finding and pharmacodynamics study as a model in order to evaluate the performance of the graph measures to monitor signal interactions. Concomitant measurements of heart rate, mean arterial blood pressure, arterial oxygen saturation, regional cerebral oxygen saturation—measured by means of near-infrared spectroscopy—and electroencephalography were performed in 22 neonates undergoing INSURE (intubation, surfactant administration, and extubation). The graphs used to study the interaction between these signal modalities were constructed using the RBF kernel. Results indicate that propofol induces a decrease in the signal interaction up to 90 minutes after propofol administration, which is consistent with clinical observations published previously. The clinical recovery phase is mainly determined by the EEG dynamics, which were observed to recover much slower compared to the other modalities. In addition, we found a more pronounced loss in cerebral-systemic interactions with increasing propofol dose.
24
Baraka Akilimali, Joël, Dieudonné Bahati Shamamba y An Ansoms. "Pressions sur les terres au Sud-Kivu (RDC). Quelle alternative face à la saturation agraire sur l’île d’Idjwi ?" Anthropologie & développement, n.º 53 (25 de octubre de 2022): 193–211. http://dx.doi.org/10.4000/anthropodev.1860.
Texto completo
25
Kim, Sung-Jae y Jin-Ho Suh. "Model-Free RBF Neural Network Intelligent-PID Control Applying Adaptive Robust Term for Quadrotor System". Drones 8, n.º 5 (1 de mayo de 2024): 179. http://dx.doi.org/10.3390/drones8050179.
Texto completoResumen
This paper proposes a quadrotor system control scheme using an intelligent–proportional–integral–differential control (I-PID)-based controller augmented with a radial basis neural network (RBF neural network) and the proposed adaptive robust term. The I-PID controller, similar to the widely utilized PID controller in quadrotor systems, demonstrates notable robustness. To enhance this robustness further, the time-delay estimation error was compensated with an RBF neural network. Additionally, an adaptive robust term was proposed to address the shortcomings of the neural network system, thereby constructing a more robust controller. This supplementary control input integrated an adaptation term to address significant signal changes and was amalgamated with a reverse saturation filter to remove unnecessary control input during a steady state. The adaptive law of the proposed controller was designed based on Lyapunov stability to satisfy control system stability. To verify the control system, simulations were conducted on a quadrotor system maneuvering along a spiral path in a disturbed environment. The simulation results demonstrate that the proposed controller achieves high tracking performance across all six axes. Therefore, the controller proposed in this paper can be configured similarly to the previous PID controller and shows satisfactory performance.
26
Bzainia, Amir, Rolando C. S. Dias y Mário Rui P. F. N. Costa. "Enrichment of Quercetin from Winemaking Residual Diatomaceous Earth via a Tailor-Made Imprinted Adsorbent". Molecules 27, n.º 19 (28 de septiembre de 2022): 6406. http://dx.doi.org/10.3390/molecules27196406.
Texto completoResumen
Residual diatomaceous earth (RDE) from winemaking activities is a rich and currently underexploited source of phenolic compounds which ought to be recycled from the perspective of circular bioeconomy. In this work, we demonstrate the feasibility of molecularly imprinted polymers (MIPs) for the enrichment of quercetin, a flavonoid at a fairly high content in residual diatomaceous earth. These MIPs were synthesized through free radical polymerization. FTIR confirmed the integration of the functional monomers into the polymeric chains. Batch adsorption experiments were used to assess the retention and selectivity of those MIPs towards quercetin. Commercial resins were compared with the synthesized materials using the same procedures. These adsorption experiments allowed the selection of the best performing MIP for the valorization of RDE extract. This treatment consisted of saturating the selected MIP with the extract and then desorbing the retained compounds using solvents of selected compositions. The desorbed fractions were analyzed using liquid chromatography, and the results demonstrated an increase in quercetin’s fractional area from 5% in the RDE extract to more than 40% in some fractions, which is roughly an eightfold enrichment of quercetin. Moreover, other flavonoids of close chemical structure to quercetin have been rather retained and enriched by the MIP.
27
Macfarlane, JC, LB Whitbourn y RA Batchelor. "Experimental Study of Noise Temperature and Conversion Loss of SIS Junction Mixers". Australian Journal of Physics 39, n.º 3 (1986): 379. http://dx.doi.org/10.1071/ph860379.
Texto completoResumen
Experiments on the performance of superconductor-insulator-superconductor (SIS) tunnel junctions as heterodyne mixers at 40 GHz are reported. The techniques developed for the fabrication of multi-junction SIS series arrays differ from, and are considerably simpler than, other methods described in the literature. Results are reported on mixer noise temperature, conversion loss, saturation, local oscillator power levels and mixer dynamic range. Factors affecting the mixer's conversion performance are identified and comparisons are made with other reported results. It is concluded that mixer performance in the present experiments is limited by imperfect impedance matching at the signal frequency, due to relatively large values of parasitic capacitance in the junctions. Future work is aimed at both reducing the junction capacitance and redesigning the mixer mount to give improved r.f. matching.
28
Xia, Guoqing, Huiyong Wu y Xingchao Shao. "Adaptive Filtering Backstepping for Ships Steering Control without Velocity Measurements and with Input Constraints". Mathematical Problems in Engineering 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/218585.
Texto completoResumen
We consider the problem of course tracking for ships with uncertainties and unknown external disturbances, in the presence of input magnitude and rate saturation. The combination of approximation-based adaptive technique and radial basis function (RBF) neural network allows us to handle the unknown disturbances from the environment and uncertain ship dynamics. By employing the adaptive filtering backstepping, the full-state feedback controller is first derived. Then the output feedback controller is designed with the unmeasurable state estimated by using a high-gain observer. In order to cope with the input constraints, an auxiliary system is introduced to the output feedback controller, and the semiglobal uniform boundedness of the modified control solution is verified. Simulation results are presented for the course tracking of a cargo ship, which are demonstrative of the excellent performance of the proposed controller.
29
Donchev, Stanislav, Tsvetan V. Tsenov y Christomir Christov. "Chemical and geochemical modeling. Thermodynamic models for binary fluoride systems from low to very high concentration (> 35 m) at 298.15 K". Acta Scientifica Naturalis 8, n.º 2 (1 de julio de 2021): 1–15. http://dx.doi.org/10.2478/asn-2021-0014.
Texto completoResumen
Abstract In this study we developed well validated thermodynamic models for solution behavior and solid-liquid equilibrium for all fluoride binary systems, for which activity data are available. The subject of modeling study are 5 fluoride systems of the type 1-1 (HF-H2O, NaF-H2O, KF-H2O, RbF-H2O, and CsF-H2O) and one of 1-2 type (H2SiF6-H2O) from low to very high concentration at 298.15 K. Models are developed on the basis of Pitzer ion interactions approach. The recommendations on mean activity coefficients (γ±) have been used to construct the model for HF-H2O system. To parameterize models for all other 5 binary systems we used all available raw experimental osmotic coefficients data (φ) for whole concentration range of solutions, and up to saturation point. The predictions of new developed here models are in excellent agreement with experimental osmotic coefficients data, and with recommendations on activity coefficients in binary solutions from low to very high concentration: up to 20 mol. kg−1 in HF-H2O, and up to 35.6 mol.kg−1 in CsF-H2O. The Deliquescence Relative Humidity (DRH (%)) and thermodynamic solubility products (as ln Ko sp) of 4 solid phases [NaF(s), KF.2H2O(s), RbF(s), and CsF(s)] have been determined on the basis of evaluated model parameters and using experimental m(sat) solubility data.
30
Lee, Seonghearn. "Accurate RF Extraction Method for Gate Voltage-Dependent Carrier Velocity of Sub-0.1㎛ MOSFETs in the Saturation Region". Journal of the Institute of Electronics and Information Engineers 50, n.º 9 (25 de septiembre de 2013): 55–59. http://dx.doi.org/10.5573/ieek.2013.50.9.055.
Texto completo
31
Hjelt, Karsten y Peter A. Krasilnikoff. "Vitamin B12 Absorption Capacity in Healthy Children". Journal of Pediatric Gastroenterology and Nutrition 5, n.º 2 (marzo de 1986): 274–77. http://dx.doi.org/10.1002/j.1536-4801.1986.tb09062.x.
Texto completoResumen
Summary:B12 absorption was investigated in 47 healthy children aged 7 months to 15.8 years (median 4.9 years). The patients had either recovered from giardiasis, the post‐gastroenteritis syndrome, or had celiac disease in remission (treated with a gluten‐free diet). The B12 absorption was measured by a double‐isotope technique using 57CoB12 and51CrCl3, the latter being the inabsorbable marker. The radiation dose was minimal. The results were presented as fractional absorption of B12 (FAB12). Within the different age groups, the absorption test was performed by means of the following oral amounts of B12: 0‐ < 1 year, 0.5 μg; 1‐3 years: 1.7 μg, 4‐6 years, 2.5 μg; 7‐10 years; 3.3 μg; and 11‐15 years, 4.5 μg. When using these oral amounts of B12, the medians (and ranges) of FAB12 were found to be: 1‐3 years (n = 18), 37% (16‐80%); 4‐6 years (n = 10), 27% (19‐40%); 7‐10 years (n = 9), 32% (21‐44%); and 11‐15 years (n = 8), 27% (19‐59%). The FAB12 in two children aged 7 and 11 months was 31% and 32%, respectively. These results may be interpretated as reference values for B12 absorption in children. Further absorption tests were performed in seven children representing the four age groups from 1 to 15 years. When a high oral amount of B12 was given (i.e., three times the saturation dose), the FAB12 ranged from 0 to 20% (median 9%), whereas a low amount (i.e., one‐ninth of the saturation dose) produced fractional absorptions from 65 to 82% (median 74%). These observations provide evidence that the saturation mechanism of B12 absorption in children is, in principle, similar to the one in adults. As the median FAB12 values for the above mentioned reference values for B12 absorption in children averaged about 30%, it may be concluded that the corresponding oral doses of B12 represent saturation amounts. Furthermore, our data show that children's absorption capacity makes it possible for them to absorb a considerable fraction of the amounts of B12 stated as Recommended Dietary Allowances (RDA) for children in the different age groups. To the best of our knowledge, this study is the first of its kind in children.
32
Banik, Partha Pratim, Shifat Hossain, Tae-Ho Kwon, Hyoungkeun Kim y Ki-Doo Kim. "Development of a Wearable Reflection-Type Pulse Oximeter System to Acquire Clean PPG Signals and Measure Pulse Rate and SpO2 with and without Finger Motion". Electronics 9, n.º 11 (13 de noviembre de 2020): 1905. http://dx.doi.org/10.3390/electronics9111905.
Texto completoResumen
Clinical devices play a vital role in diagnosing and monitoring people’s health. A pulse oximeter (PO) is one of the most common clinical devices for critical medical care. In this paper, we explain how we developed a wearable PO. We propose a new electronic circuit based on an analog filter that can separate red and green photoplethysmography (PPG) signals, acquire clean PPG signals, and estimate the pulse rate (PR) and peripheral capillary oxygen saturation (SpO2). We propose a PR and SpO2 measurement algorithm with and without the motion artifact. We consider three types of motion artifacts with our acquired clean PPG signal from our proposed electronic circuit. To evaluate our proposed algorithm, we measured the accuracy of our estimated SpO2 and PR. To evaluate the quality of our estimated PR (bpm) and SpO2 (%) with and without the finger motion artifact, we used the quality evaluation metrics: mean absolute percentage error (MAPE), mean absolute error (MAE), and reference closeness factor (RCF). Without the finger motion condition, we found that our proposed wearable PO device achieved an average 2.81% MAPE, 2.08 bpm MAE, 0.97 RCF, and 98.96% SpO2 accuracy. With a finger motion, the proposed wearable PO device achieved an average 4.5% MAPE, 3.66 bpm MAE, 0.96 RCF, and 96.88% SpO2 accuracy. We also show a comparison of our proposed PO device with a commercial Fingertip PO (FPO) device. We have found that our proposed PO device performs better than the commercial FPO device under finger motion conditions. To demonstrate the implementation of our wearable PO, we developed a smartphone app to allow the PO device to share PPG signals, PR, and SpO2 through Bluetooth communication. We also show the possible applications of our proposed PO as a wearable, hand-held PO device, and a PPG signal acquisition system.
33
Kladias, N. y V. Prasad. "Natural Convection in Horizontal Porous Layers: Effects of Darcy and Prandtl Numbers". Journal of Heat Transfer 111, n.º 4 (1 de noviembre de 1989): 926–35. http://dx.doi.org/10.1115/1.3250807.
Texto completoResumen
Natural convection in horizontal porous layers heated from below is studied by employing a formulation based on the Brinkman–Forchheimer–extended Darcy equation of motion. The numerical solutions show that the convective flow is initiated at lower fluid Rayleigh number Raf than that predicted by the linear stability analysis for the Darcy flow model. The effect is considerable, particularly at a Darcy number Da greater than 10−4. On the other hand, an increase in the thermal conductivity of solid particles has a stabilizing effect. Also, the Rayleigh number Raf required for the onset of convection increases as the fluid Prandtl number is decreased. In the stable convection regime, the heat transfer rate increases with the Rayleigh number, the Prandtl number, the Darcy number, and the ratio of the solid and fluid thermal conductivities. However, there exists an asymptotic convection regime where the porous media solutions are independent of the permeability of the porous matrix or Darcy number. In this regime, the temperature and flow fields are very similar to those obtained for a fluid layer heated from below. Indeed, the Nusselt numbers for a porous medium with kf = ks match with the fluid results. The effect of Prandtl number is observed to be significant for Prf < 10, and is strengthened with an increase in Raf, Da, and ks/kf. An interesting effect, that a porous medium can transport more energy than the saturating fluid alone, is also revealed.
34
Sihombing, Helda Agave y Inte Christinawati Buulolo. "PENGENALAN BUAH KOPI BERDASARKAN PARAMETER WARNA MENGGUNAKAN ALGORITMA BACKPROPAGATION DAN ALGORITMA SUPPORT VECTOR MACHINE (SVM)". SEMINASTIKA 3, n.º 1 (1 de noviembre de 2021): 26–32. http://dx.doi.org/10.47002/seminastika.v3i1.234.
Texto completoResumen
Salah satu kopi arabika unggulan Indonesia adalah Kopi Lintong yang berasal dari Sumatera Utara. Peneliti akan melakukan 2 percobaan yaitu percobaan I untuk memperoleh model terbaik dalam melakukan klasifikasi buah kopi arabika varietas Sigarar Utang. Sedangkan percobaan II dilakukan untuk mengetahui objek mana yang lebih baik digunakan dalam klasifikasi kopi berkualitas berdasarkan parameter warna, apakah buah kopi atau biji kopi. Dataset yang digunakan pada percobaan I adalah berupa 250 gambar buah kopi kualitas baik dan 250 gambar buah kopi kualitas kurang yang diambil langsung dari KSU POM Humbang Cooperative. Kemudian dilakukan image preprocessing yang menghasilkan 2500 gambar baru. Sedangkan dataset yang digunakan pada percobaan II adalah data buah kopi dan biji kopi. Buah kopi terdiri dari 240 gambar buah kopi baik dan 240 gambar buah kopi cacat hasil image rotation. Biji kopi terdiri dari 240 gambar biji kopi baik dan 240 gambar biji kopi cacat. Data tersebut kemudian akan dilakukan ekstraksi fitur dengan menggunakan metode HSV (Hue, Saturation, Value). Selanjutnya akan dilakukan proses learning menggunakan algoritma Backpropagation dan algoritma Support Vector Machine dengan tiga jenis kernel yaitu RBF, polynomial, dan sigmoid. Berdasarkan pengujian yang telah dilakukan, maka diperoleh hasil pada percobaan I menghasilkan model klasifikasi terbaik dengan menggunakan algoritma SVM dengan kernel RBF menghasilkan nilai akurasi sebesar 86% dan nilai f-score sebesar 86%. Untuk percobaan II memperoleh hasil bahwa buah kopi dan biji kopi baik digunakan sebagai objek dalam pengenalan buah kopi berdasarkan fitur warna dengan menggunakan machine learning.
35
Durham, Richard, Gloria Moore y Charles Guy. "LINKAGE OF RESTRICTION FRAGMENT LENGTH POLYMORPHISMS AND ISOZYMES IN A BACKCROSS OF CITRUS AND PONCIRUS". HortScience 25, n.º 9 (septiembre de 1990): 1154d—1154. http://dx.doi.org/10.21273/hortsci.25.9.1154d.
Texto completoResumen
Genetic linkage analysis was performed on an interspecific backcross of citrus [Citrus grandis (L.) Osbeck cv. Thong Dee X (Thong Dee X Poncirus trifoliata (L.) Raf. cv. Pomeroy)], using restriction fragment length polymorphism (RFLP) and isozyme analysis. Sixty-five progeny were analyzed for a total of 57 segregating markers including 9 isozymes and 48 RFLPs. Significant (p = 0.05) deviation from an expected 1:1 segregation ratio was observed for 21 (37%) of the 57 loci, but this did not exclude their use in the mapping study. Linkage analysis revealed that 50 loci mapped to 12 linkage groups while 7 loci segregated independently from all other markers. The total map distance included in the 12 linkage groups was 472 cM with the mean distance between markers being 12.8 cM. This does not represent a saturation of the genome with markers; however, this work demonstrates the potential for mapping traits of economic importance in citrus.
36
Karunasinghe, Nishi, Jacqueline Ryan, John Tuckey, Jonathan Masters, Michael Jamieson, Larry C. Clarke, James R. Marshall y Lynnette R. Ferguson. "DNA Stability and Serum Selenium Levels in a High-Risk Group for Prostate Cancer". Cancer Epidemiology, Biomarkers & Prevention 13, n.º 3 (1 de marzo de 2004): 391–97. http://dx.doi.org/10.1158/1055-9965.391.13.3.
Texto completoResumen
Abstract The essential micronutrient, selenium, is at low levels in the New Zealand diet. Selenium is a component of a number of proteins involved in the maintenance of genomic stability, and recommended daily allowances (RDA) are set on saturation levels for glutathione peroxidase (GPx), a key enzyme in surveillance against oxidative stress. It has been assumed but not proven that this level will be adequate for other key selenoenzymes. The “Negative Biopsy Trial” identifies a group of New Zealand individuals at high risk of prostate cancer, whose serum selenium levels will be monitored and who will be supplemented with a yeast-based tablet, with or without selenium, over an extended time. Access to patients on this trial provides the opportunity to ask the more generic question as to whether selenium levels in this population are adequate to maintain genomic stability. The single cell gel electrophoresis (comet) assay was used to study DNA damage in blood leukocytes harvested from these volunteers. Average serum selenium levels before randomization was 97.8 ± 16.6 ng/ml, low by international standards. For the half of the population below this mean value, lower serum selenium levels showed a statistically significant inverse relationship (P = 0.02) with overall accumulated DNA damage. Although other interpretations cannot be excluded, the data suggest that the selenium intake in half of this population is marginal for adequate repair of DNA damage, increasing susceptibility to cancer and other degenerative diseases. It also raises the question as to whether glutathione peroxidase saturation levels are appropriate indicators of the optimal selenium levels for a given population.
37
Qi, Shuaiyang, Huaiqing Zhang y Meng Zhang. "Net Primary Productivity Estimation of Terrestrial Ecosystems in China with Regard to Saturation Effects and Its Spatiotemporal Evolutionary Impact Factors". Remote Sensing 15, n.º 11 (31 de mayo de 2023): 2871. http://dx.doi.org/10.3390/rs15112871.
Texto completoResumen
The net primary productivity (NPP) of vegetation holds a pivotal character for the global carbon balance as a key parameter for characterizing terrestrial ecological processes. The most commonly used indices for estimating vegetation NPP, for instance, the normalized difference vegetation index (NDVI), often suffer from saturation issues that can compromise the accuracy of NPP estimation. This research utilizes a new vegetation index based on the radial basis function (RBF) to estimate vegetation NPP in Chinese terrestrial ecosystems over the past two decades (2001–2020) and investigates the spatiotemporal variation characteristics of NPP and the driving mechanisms. The results indicate that the kernel vegetation index (kNDVI) can effectively alleviate the saturation problem and significantly improve the accuracy of NPP estimation compared to NDVI. Over the past two decades, the NPP of Chinese terrestrial vegetation ranged from 64.13 to 79.72 g C/m2, with a mean value of 72.75 g C/m2, showing a fluctuating upward trend. Changes in the NPP of terrestrial ecosystems in China are mainly affected by precipitation. The dominant factors influencing NPP changes varied over time and had different impacts. For instance, in the period of 2001–2005 the climate had a positive effect on NPP changes, with the dominant factors being evaporation and precipitation. However, in the period of 2010–2015 the dominant climate factors shifted to evaporation and temperature, and their effect on NPP changes became negative. The outcomes of this research aim to serve as a foundation for carbon cycle research and ecosystem environment construction in China.
38
Kurnik, B. R., L. S. Weisberg y P. B. Kurnik. "Renal and systemic oxygen consumption in patients with normal and abnormal renal function." Journal of the American Society of Nephrology 2, n.º 11 (mayo de 1992): 1617–26. http://dx.doi.org/10.1681/asn.v2111617.
Texto completoResumen
Systemic and renal oxygen consumption and hemodynamics were studied in patients with normal renal function (NI; serum creatinine concentration (Screat), 1.0 +/- 0.04 mg/dL) and those with moderate chronic renal failure with diabetes mellitus Screat, 2.7 +/- 0.2 mg/dL) or without diabetes mellitus (Screat, 2.4 +/- 0.1 mg/dL). Patients with chronic renal failure were anemic and had normal systemic oxygen consumption (NI, 10,564 +/- 277; chronic renal failure, 9,669 +/- 362 mumol of O2/min) and elevated systemic oxygen extraction (NI, 22.9 +/- 1; chronic renal failure, 30.9 +/- 1.2%) (P less than 0.02). Cardiac output and index and arterial oxygen saturation were equivalent in normal patients and in patients with chronic renal failure. Patients with chronic renal failure had higher renal oxygen extraction (NI, 7.3 +/- 0.8; chronic renal failure, 13.9 +/- 1%), lower RBF (NI, 572 +/- 146; chronic renal failure, 197 +/- 20 mL/min/kidney), and lower renal oxygen consumption per kidney (NI, 391 +/- 101; chronic renal failure, 177 +/- 20 mumol of O2/min/kidney) than did normal patients (P less than 0.02). There was a linear relationship between hemoglobin and RBF (r = 0.47, P less than 0.02). Patients with chronic renal failure and diabetes had lower RBF (diabetes mellitus, 146 +/- 23; without diabetes, 242 +/- 28 mL/min/kidney) and renal oxygen consumption per kidney (diabetes mellitus, 131 +/- 21; without diabetes, 218 +/- 29 mumol of O2/min/kidney (P less than 0.03) but equivalent renal oxygen extraction when compared with patients without diabetes. Patients with chronic renal failure without diabetes mellitus had higher renal oxygen consumption when expressed per 100 mL of creatinine clearance (diabetes mellitus, 1,016 +/- 150; without diabetes mellitus, 1,453 +/- 175 mumol of O2/min/100 mL of creatinine clearance; P less than 0.03). There was a significant linear relationship (P less than 0.005, r = 0.38) between calculated creatinine clearance and renal oxygen consumption with a y intercept representing basal renal oxygen consumption (115 mumol of O2/min/kidney) and a slope of 2.3 mumol of O2/mL. Patients with moderate chronic renal failure have normal systemic oxygen consumption but reduced RBF and renal oxygen consumption. The latter parameters are even lower in patients with chronic renal failure and diabetes. Renal hypermetabolism is more likely to exist in nondiabetic than diabetic renal disease. Basic human renal physiology and pathophysiology are described by the relationships between renal oxygen consumption, blood flow, oxygen extraction, and creatinine clearance in patients with normal and abnormal renal function of varied cause.
39
Zhang, Jianhua y Yinguang Li. "Adaptive RBF Neural Network Tracking Control of Stochastic Nonlinear Systems with Actuators and State Constraints". Mathematics 12, n.º 9 (30 de abril de 2024): 1378. http://dx.doi.org/10.3390/math12091378.
Texto completoResumen
This paper investigates the adaptive neural network (NN) tracking control problem for stochastic nonlinear systems with multiple actuator constraints and full-state constraints. The issue of system full-state constraints is tackled by a generalized barrier Lyapunov function (GBLF), and the output constraints of the system are considered to be in the form of time-varying functions, which are more in line with the needs of real physical systems. The NN approximation technique is utilized to overcome the influence of the uncertainty term on controller design due to randomness. Based on the backstepping technique, a neural adaptive fixed-time tracking control strategy is designed. Under the designed control strategy, the tracking accuracy of the controlled system can reach the expectation in a fixed time. The multi-actuator constraints are converted into a generalized mathematical model to simplify the controller design process. Using the characteristics of the hyperbolic tangent function, a new function called practical virtual control signal is designed using the virtual control signal as the input. Due to the saturation constraint property of the hyperbolic tangent function, it is theoretically ensured that no state of the system exceeds the constraints through to the new form of the virtual controller. Using the adaptive controller constructed in this paper, the controlled system is semi-global fixed-time stabilized in probability (SGFSP). Finally, the effectiveness of the proposed control strategy is further verified by simulation examples.
40
Blanco-Rojo, Ruth, Ana M. Pérez-Granados, Laura Toxqui, Carmen González-Vizcayno, Marco A. Delgado y M. Pilar Vaquero. "Efficacy of a microencapsulated iron pyrophosphate-fortified fruit juice: a randomised, double-blind, placebo-controlled study in Spanish iron-deficient women". British Journal of Nutrition 105, n.º 11 (8 de febrero de 2011): 1652–59. http://dx.doi.org/10.1017/s0007114510005490.
Texto completoResumen
Fe-deficiency anaemia is a worldwide health problem. We studied the influence of consuming an Fe-fortified fruit juice on Fe status in menstruating women. A randomised, double-blind, placebo-controlled study of 16 weeks of duration was performed. Subjects were randomised into two groups: the P group (n58) or the F group (n64), and consumed, as a supplement to their usual diet, 500 ml/d of a placebo fruit juice or an Fe-fortified fruit juice, respectively. The Fe-fortified fruit juice, containing microencapsulated iron pyrophosphate, provided 18 mg Fe/d (100 % of the RDA). At baseline and monthly, dietary intake, body weight and Fe parameters were determined: total erythrocytes, haematocrit, mean corpuscular volume (MCV), red blood cell distribution width (RDW), Hb, serum Fe, serum ferritin, serum transferrin, transferrin saturation, soluble transferrin receptor (sTfR) and zinc protoporphyrin (ZnPP). The fruit juice consumption involved increased intake of carbohydrates and vitamin C, and increased BMI within normal limits. Ferritin was higher in the F group after week 4 (P < 0·05) and became 80 % higher than in the P group after week 16 (P < 0·001), and transferrin decreased in the F group compared with the P group after week 4 (P < 0·001). RDW was higher at weeks 4 and 8 in the F group compared with the P group (P < 0·05). Transferrin saturation increased after week 8, and haematocrit, MCV and Hb increased after week 12, in the F group compared with the P group. Serum Fe did not change. sTfR and ZnPP decreased in the F group at week 16 (P < 0·05). Iron pyrophosphate-fortified fruit juice improves Fe status and may be used to prevent Fe-deficiency anaemia.
41
Železnik, Igor, Doroteja Čatorič y Mihael J. Toman. "Distribution of epilithic diatoms in the Savinja River flowing through an urban landscap". Acta Biologica Slovenica 59, n.º 2 (1 de diciembre de 2016): 57–72. http://dx.doi.org/10.14720/abs.59.2.15870.
Texto completoResumen
The catchment area in urban and agricultural landscapes is greatly influenced by human activities that reflect also in physical and chemical characteristics of water as well as in species diversity in water bodies. The diversity and the species composition of epilithic diatom communities in the Savinja River, as well as basic environmental parameters were analysed. Sampling sites were selected in reaches subjected to different influences from the catchment area and with different physical and chemical characteristics. Samples were collected at the site where the Savinja River enters the urban area of the town Celje, at the end of urban landscape and downstream of the Celje waste water treatment plant outflow. The most common and dominant diatom species in the periphyton community was Achnanthes biasolettiana. Other common diatom taxa that were found in all samples and at least in one sample exceeded relative abundance of 10% were Nitzschia fonticola, Amphora pediculus and Nitzschia dissipata. The results of the redundancy analyses (RDA) revealed that the variance of the epilithic diatom community was explained by O2 saturation(35%) and saprobic index (33% of TVE). Diatom species richness was positively correlated with O2 saturation. Shannon-Wienerdiversity index was positively correlated with saprobic index values based on all algae and trophic index calculated on the base of diatoms indicating a relatively low organic matter and nutrient input into the river system. The results showed that no significant changes in epilithic diatom species composition and no negative impacts on diversity of epilithic diatom community in the Savinja River were detected on its flow through the urban landscape. Moreover, changes between the seasons were more evident than changes between sampling sites, confirming the importance of sampling date for monitoring.
42
Chen, Lifeng, Kai Chen, Genyi He y Zhiqi Liu. "Research on the Prediction Model of Loess Collapsibility in Xinyuan County, Ili River Valley Area". Water 15, n.º 21 (29 de octubre de 2023): 3786. http://dx.doi.org/10.3390/w15213786.
Texto completoResumen
Collapsibility is a unique engineering geological property of loess. Choosing appropriate parameters to build the prediction model of loess collapsibility is an essential step toward solving the loess collapsibility problem. A case study was performed for the loess in Xinyuan County of the Yili River Basin, China. A large amount of data was collected from preliminary geotechnical tests in this region. Mathematical statistics were applied to analyse the correlations between the loess collapsibility and soil parameters. Multiple linear regression and neural network theories were adopted to build this region’s prediction model of loess collapsibility. The results showed that microscopically, the soils in this region were predominantly flocculated structures. The soil particles were flaky and in bracket contact, and the pores were round or irregularly shaped. Regarding the material composition, the soils were primarily composed of quartz and albite, with a low hematite content. In the study area, the correlation coefficients between the collapsibility coefficient of the loess vs. the density, dry density, saturation, porosity ratio, and porosity varied between 0.628 and 0.857, indicating a strong or very strong correlation. In terms of predicting loess collapsibility, the effectiveness of neural networks based on RBF (radial basis function) and multiple linear regression models was contrasted. The latter was discovered to be more appropriate, dependable, and accurate, with an accuracy percentage of 94.42%. Simultaneously, the model’s assessment index is 0.014 for the root mean squared error (RMSE), 0.962 for the correlation coefficient (CC), 0.919 for the Nash–Sutcliffe efficiency coefficient (NSE), and −1.494 percent for the percent bias (PBIAS). It works well for estimating whether local loess may collapse. Therefore, the RBF neural network model built in the present study has adequate precision and meets the engineering requirements. Our research sheds new light on loess collapsibility assessment in this region.
43
Cheng, Jun, Baitao Zhang, Haoyu Mao y Sichuan Xu. "Modeling and Fuzzy Feedforward Control of Fuel Cell Air Supply System". World Electric Vehicle Journal 12, n.º 4 (9 de octubre de 2021): 181. http://dx.doi.org/10.3390/wevj12040181.
Texto completoResumen
As an important part of the fuel cell subsystem, the air supply system of the proton exchange membrane fuel cell (PEMFC) plays an important role in improving the output performance and durability of fuel cells. It is necessary to control the oxygen excess ratio of fuel cell systems in the process of variable load, preventing the oxygen starvation in the loading process and excessive parasitic power consumption caused by oxygen saturation. At this time, the modeling of fuel cell systems and the development of control strategies are critical. The development of a control strategy depends on the construction of the control model. Aiming at the difficulty of air supply system modeling, this paper uses radial basis function (RBF) neural network and state equation method to establish the dynamic model of air supply systems. At the same time, PID, fuzzy logic plus PID (FL + PID), feedforward plus PID (FF + PID), fuzzy feedforward plus fuzzy PID (FF + FLPID) control strategy are proposed to control the oxygen excess ratio of the system. The simulation results show that fuzzy feedforward plus fuzzy PID (FF + FLPID) has the best effect and the oxygen excess ratio can be followed in 1 s.
44
Yang, Junxia, Youpeng Zhang y Yuxiang Jin. "Optimization of Urban Rail Automatic Train Operation System Based on RBF Neural Network Adaptive Terminal Sliding Mode Fault Tolerant Control". Applied System Innovation 4, n.º 3 (5 de agosto de 2021): 51. http://dx.doi.org/10.3390/asi4030051.
Texto completoResumen
Aiming at the problem of the large tracking error of the desired curve for the automatic train operation (ATO) control strategy, an ATO control algorithm based on RBF neural network adaptive terminal sliding mode fault-tolerant control (ATSM-FTC-RBFNN) is proposed to realize the accurate tracking control of train operation curve. On the one hand, considering the state delay of trains in operation, a nonlinear dynamic model is established based on the mechanism of motion mechanics. Then, the terminal sliding mode control principle is used to design the ATO control algorithm, and the adaptive mechanism is introduced to enhance the adaptability of the system. On the other hand, RBFNN is used to adaptively approximate and compensate the additional resistance disturbance to the model so that ATO control with larger disturbance can be realized with smaller switching gain, and the tracking performance and anti-interference ability of the system can be enhanced. Finally, considering the actuator failure and the control input limitation, the fault-tolerant mechanism is introduced to further enhance the fault-tolerant performance of the system. The simulation results show that the control can compensate and process the nonlinear effects of control input saturation, delay, and actuator faults synchronously under the condition of uncertain parameters, external disturbances of the system model and can achieve a small error tracking the desired curve.
45
Dixit, T., G. Authelet, C. Mailleret, F. Gouit y B. Baudouy. "Experimental investigation of vertical neon pulsating heat pipe for superconducting magnet cooling application". IOP Conference Series: Materials Science and Engineering 1240, n.º 1 (1 de mayo de 2022): 012076. http://dx.doi.org/10.1088/1757-899x/1240/1/012076.
Texto completoResumen
Abstract Pulsating heat pipes (PHPs) are two-phase flow, thermal transport carriers characterized by ease of fabrication, flexibility of compactness and variable heat transfer capability. Conventionally, cooling of superconducting magnets is realized by using cryogen cooling system. Cryogenic PHPs are emerging as the new-age economical alternative that can passively contribute in efficient transport of generated heat to active cryocoolers. Nevertheless, a number of challenges must be addressed to materialize this union. For this objective, a multipurpose experimental test-rig has been developed which will allow different critical parameters of cryogenic PHPs to be investigated. The preliminary tests are conducted using neon as the working fluid. The PHP capillaries, made of SS304, have an outer diameter of 2.5 mm and a projected length of 400 mm with the adiabatic part having twice the length as compared to that in the condenser and evaporator. It consists of 20 parallel tubes forming a closed-loop and are tested in gravity-assisted environment. Employing the Sumitomo RDE-418D4 4K Cryocooler, the condenser temperature is controlled at the neon saturation temperature, around 27 K. The thermal performance of this cryogenic PHP is recorded at different evaporator heat load conditions. We report here the temperature evolution of PHP evaporator, and condenser as well as the pressure oscillations with time.
46
Pessoa, L. A., P. C. Paiva, R. Paranhos, M. A. V. Freitas y C. A. Echeverría. "Intra-annual variation in rainfall and it’s influence of the adult’s Cyprideis spp (Ostracoda, Crustacea) on a eutrophic estuary (Guanabara Bay, Rio de Janeiro, Brazil)." Brazilian Journal of Biology 80, n.º 2 (junio de 2020): 449–59. http://dx.doi.org/10.1590/1519-6984.216263.
Texto completoResumen
Abstract Spatial and temporal distribution of two species of adult´s ostracods (Cyprideis sp. and Cyprideis salebrosa) were studied as a function of the rainfall patterns in the Guanabara Bay, Rio de Janeiro, Brazil. Samples were taken in ten stations, along six surveys representing three periods (Dry, Early and Late Rainy) for two years. Stations were nested in four areas (Outer, Central, EPA Guapimirim and Impacted). The bottom water (temperature, salinity, dissolved oxygen and oxygen saturation) were measured in each area to characterize the influence of seasonal variations by rainfall. Cyprideis sp. and Cyprideis salebrosa showed patterns distribution to seasonality/surveys (p = 0,002 and p <0,001, respectly). The spatial distribution of Cyprideis sp was significantly different areas studied (p <0.001) indicated well defined areas and distribution in along of the surveys. However, C. salebrosa showed homogeneous distribution in along of the areas within of each survey (p <0.001). Redundancy Analysis (RDA) for the two years evidenced environment preference of the Cyprideis sp. for areas with marine conditions (high influence for channel central) and C. salebrosa for brackish water (high influence of the rivers). This observation reinforces of the existence of areas created by the seasonality of pluviometric regime, a possible dispersion of the adult’s ostracods and possibility the use with bioindicators.
47
Shaban, Mohamed. "Effect of Pore Thickness and the State of Polarization on the Optical Properties of Hexagonal Nanoarray of Au/Nanoporous Anodic Alumina Membrane". Journal of Nanomaterials 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/347486.
Texto completoResumen
Hexagonal nanoarrays of Au particles were deposited on nanoporous anodic alumina membrane (NAAM) utilizing r.f. magnetron sputtering. The thickness of the NAAMs is adjusted by changing the second anodization time from 5 min to 20 min. The surface morphology, composition, and optical properties are characterized by using SEM, EDX, and spectrophotometer, respectively. The effects of the NAAM thickness and state of polarization on the morphological changes and on the optical properties of the fabricated nanoarrays were addressed. According to the measured optical spectra, the rate of decrease of NAAMs refractive index was found to be 3.825 × 10−4 nm−1. Using the modified Kubelka-Munk radiative transfer model, the energy gap of NAAMs was calculated from diffused reflectance and was decreased from 1.682 to 1.376 as the anodization time increased from 5 to 20 min. Also, the saturation of interference fringes is substantially enhanced, and field enhancement can be achieved due to the excitation and constructive interference of surface plasmon waves by coating NAAMs with the hexagonal nanoarrays of Au. Based on the advantages of the fabrication approach and the enhanced and controlled properties, this new generation of samples can be used as promising building blocks for nanophotonic and nanoelectronics devices.
48
Islam, Md Rashedul, Md Amiruzzaman, Shahriar Nasim y Jungpil Shin. "Smoke Object Segmentation and the Dynamic Growth Feature Model for Video-Based Smoke Detection Systems". Symmetry 12, n.º 7 (30 de junio de 2020): 1075. http://dx.doi.org/10.3390/sym12071075.
Texto completoResumen
This article concerns smoke detection in the early stages of a fire. Using the computer-aided system, the efficient and early detection of smoke may stop a massive fire incident. Without considering the multiple moving objects on background and smoke particles analysis (i.e., pattern recognition), smoke detection models show suboptimal performance. To address this, this paper proposes a hybrid smoke segmentation and an efficient symmetrical simulation model of dynamic smoke to extract a smoke growth feature based on temporal frames from a video. In this model, smoke is segmented from the multi-moving object on the complex background using the Gaussian’s Mixture Model (GMM) and HSV (hue-saturation-value) color segmentation to encounter the candidate smoke and non-smoke regions in the preprocessing stage. The preprocessed temporal frames with moving smoke are analyzed by the dynamic smoke growth analysis and spatial-temporal frame energy feature extraction model. In dynamic smoke growth analysis, the temporal frames are segmented in blocks and the smoke growth representations are formulated from corresponding blocks. Finally, the classifier was trained using the extracted features to classify and detect smoke using a Radial Basis Function (RBF) non-linear Gaussian kernel-based binary Support Vector Machine (SVM). For validating the proposed smoke detection model, multi-conditional video clips are used. The experimental results suggest that the proposed model outperforms state-of-the-art algorithms.
49
Coates, K. Dave y Philip J. Burton. "Growth of planted tree seedlings in response to ambient light levels in northwestern interior cedar-hemlock forests of British Columbia". Canadian Journal of Forest Research 29, n.º 9 (15 de septiembre de 1999): 1374–82. http://dx.doi.org/10.1139/x99-091.
Texto completoResumen
Insights into field-planted conifer seedling growth were gained by fitting height and diameter growth to relative irradiance over the growing season using Michaelis-Menten functions. There was little difference among tree species (Abies lasiocarpa (Hook.) Nutt., Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carr., Pinus contorta Dougl. ex Loud., Thuja plicata Donn ex D. Don, Tsuga heterophylla (Raf.) Sarg.) in response to ambient light. No significant differences in whole-plant compensation points were observed among species but the ranking of species' compensation points was consistent with their shade-tolerance ranking. Five years after planting, total size and recent growth rates varied little among species from low to high light, implying an absence of trade-offs in low- and high-light growth strategies. Thuja plicata had the greatest response to increased light under deep shade (<20% relative irradiance). All species increased growth above 40% relative irradiance, with no clear whole-plant light saturation point evident under field conditions. Growth rates at high light were broadly overlapping and varied considerably within species. As expected,Pinus contorta growth exceeded that of other species above 70% relative irradiance, but it also exhibited high growth rates at low light. Greatest variability among species was at intermediate light levels (30-70% relative irradiance) where careful matching of tree species to light environment can maximize growth rates.
50
Bergström, Erik, Olle Kernell, Bo Lönnerdal y Lars Åke Persson. "Sex Differences in Iron Stores of Adolescents". Journal of Pediatric Gastroenterology and Nutrition 20, n.º 2 (febrero de 1995): 215–24. http://dx.doi.org/10.1002/j.1536-4801.1995.tb11537.x.
Texto completoResumen
SummaryWe evaluated iron status and its determinants in healthy adolescents. Fasting morning blood samples from a school‐based cross‐sectional study were analyzed for serum ferritin (SF), serum iron, total iron‐binding capacity, and circulating transferrin receptors. Physical development, chronic disease, medication, dietary intake, and physical activity were assessed using clinical examination, questionnaires, and 7‐day records. The risk of having low serum ferritin values was estimated using bivariate and multivariate regression. Subjects were 867 healthy Swedish adolescents, 14− and 17‐year‐olds (472 boys and 395 girls). SF values increased with pubertal stage in boys but not in girls. Five percent of the boys and 15% of the girls had SF values <12 μg/L. Of the 17‐year‐old boys, 7% compared to 1% of the 17‐year‐old girls had SF values > 100 μg/L. Forty‐one percent of cases with SF values >12 μg/L had serum iron values < 15 μM, and 22% had transferrin saturation values <16%. Mean total iron intakes of the boys were high [1.6 times recommended daily allowance (RDA)] and mean intakes of the girls were adequate (0.9 times RDA). Low heme iron intakes increased the risk of low iron stores (<12 μg/L) in girls but not in boys. Total iron intake or other dietary factors, physical development, or level of physical activity did not influence the risk of low SF. The findings of this study suggest that the differences in iron status between boys and girls in adolescence results primarily from biological differences other than menstrual bleeding or insufficient iron intake. Furthermore, the results question the role of SF as an indicator of iron deficiency in adolescence, in particular if age and sex are not taken into consideration. We suggest that different reference values for SF, including the cut‐off limit for low SF, adjusted for age and sex, should be considered. The high iron intakes and corresponding high SF values found in the older boys are noticeable in light of the possible negative health consequences of iron overload.