Steady-state Period Research Articles

Cost analysis of 2-out-of-4 system connected to two-unit parallel supporting device for operation

This paper studied cost analysis of a hybrid series–parallel system consisting of two subsystems A and B. Subsystem A has two units in active parallel; while subsystem B consists of 2-out-of-4 units. Both units have exponential failure and repair time. Through transition rate table, system of first-order linear differential equations is developed and solved to obtain the explicit expressions for the steady-state availability and busy period probability of repairman due to partial and complete failure of both supporting devices, and the corresponding profit function is derived and examined. Furthermore, the results of the proposed model are beneficial for system engineers and designers, reliability and maintenance managers.

Increased Iron Status during a Feeding Trial of Iron-Biofortified Beans Increases Physical Work Efficiency in Rwandan Women

ABSTRACTBackgroundIron-biofortified staple foods can improve iron status and resolve iron deficiency. However, whether improved iron status from iron biofortification can improve physical performance remains unclear.ObjectiveThis study aimed to examine whether changes in iron status from an iron-biofortified bean intervention affect work efficiency.MethodsA total of 125 iron-depleted (ferritin <20 μg/L) female Rwandan university students (18–26 y) were selected from a larger sample randomly assigned to consume iron-biofortified beans (Fe-Bean; 86.1 mg Fe/kg) or conventional beans (control: 50.6 mg Fe/kg) twice daily for 18 wk (average of 314 g beans consumed/d). Blood biomarkers of iron status (primary outcome) and physical work efficiency (secondary outcome) were measured before and after the intervention. Work performed was assessed during 5-min steady-state periods at 0-, 25-, and 40-W workloads using a mechanically braked cycle ergometer. Work efficiency was calculated at 25 W and 40 W as the work accomplished divided by the energy expended at that workload above that expended at 0 W. General linear models were used to evaluate the relation between changes in iron status biomarkers and work efficiency.ResultsThe Fe-Bean intervention had significant positive effects on hemoglobin, serum ferritin, and body iron stores but did not affect work efficiency. However, 18-wk change in hemoglobin was positively related to work efficiency at 40 W in the full sample (n = 119; estimate: 0.24 g/L; 95% CI: 0.01, 0.48 g/L; P = 0.044) and among women who were anemic (hemoglobin <120 g/L) at baseline (n = 43; estimate: 0.64 g/L; 95% CI: 0.05, 1.23 g/L; P = 0.036). Among women who were nonanemic at baseline, change in serum ferritin was positively related to change in work efficiency at 40 W (n = 60; estimate: 0.50 μg/L; 95% CI: 0.06, 0.95 μg/L; P = 0.027).ConclusionsIncreasing iron status during an iron-biofortified bean feeding trial improves work efficiency in iron-depleted, sedentary women. This trial was registered at clinicaltrials.gov as NCT01594359.

Hybrid Power System Frequency Control including Wind Farm using Battery Storage System

Fixed speed wind turbine-squirrel cage induction generator (FSWT-SCIG) based wind farm (WF) is increasing significantly. However, FSWT-SCIG have no frequency control capability, which creates a significant problem on power system steady-state stability. This paper represents a new operational strategy to control frequency of the entire power system including large-scale FSWT-SCIG based WF by using battery storage system (BSS). The proposed cascaded control of BSS is designed to provide effective amount of real power during steady-state period to damp frequency fluctuations. To evaluate the validity of the proposed system, simulation studies are executed on a reformed IEEE nine-bus power system with three synchronous generators (SGs) and SCIG-based WF along with BSS. The simulation results indicate that the proposed system can be an effective solution to reduce frequency fluctuations of the hybrid power system during steady-state condition.

Predicting behaviour of the Indus basin aquifer susceptible to degraded environment in the Punjab province, Pakistan

Rapid changes in the irrigated system due to climate change and drastic growth in urbanization and industrialization have raised serious concerns related to available groundwater resources of the Indus basin on which millions of people depend upon for their sustenance. Under the prevailing scenario, three-dimensional numerical groundwater flow model Visual MODFLOW has been used to evaluate the regional groundwater flow from the steady-state period of 1987 (used as a base to run the model for several simulation periods) up to the predictive period of 2030 for sustainable water resource management in the Indus plain of Pakistan. The steady-state calibration of the model indicated a close agreement between the simulated and the observed heads as indicative from the residual mean value of 0.10 m and an absolute residual mean of 0.47 m. The velocity vectors of the groundwater flow indicate that in most parts of the study area groundwater is discharged into the Jhelum and Chenab rivers. In the transient-state condition, groundwater levels indicated a rising trend till 1989, but as the irrigated area tends to increase continuously, the heads started to drop from year 1991 onward at an average rate of 0.45 m/year. The Bari Doab in the south appears to be more under stress than the Rechna and the Lower Chaj Doabs because of the overexploitation of groundwater, low flows in the Ravi River and less recharge from rainfall. The negative impacts of environment changes on the underlying aquifer could be minimized through long-term monitoring of the groundwater system and adoption of integrated water resource management approach in future.

Experimental investigation on control of temperature asymmetry and nonuniformity in a pilot scale thermal flow reversal reactor

Temperature asymmetry along flow direction and nonuniformity vertical to flow direction have been the prominent obstacles to the stable operation of thermal flow reversal reactor (TFRR) devices in industry. However, the relevant investigations are sorely lacking especially through the experiment method due to the limitation of laboratory test conditions. In this study, temperature asymmetry and nonuniformity for extra lean CH4/air combustion (feed methane concentration below 1 vol%) in a pilot TFRR were investigated experimentally. The effects of the preheating process and feed methane concentration were investigated. The switching time of 120 s and feed rate of 400 m3/h were determined for the preheating process. In the transition period between preheating completion and cyclic steady state achievement, the operation pattern with preheater off was beneficial to heat storage. Stable combustion for minimum feed methane concentration of 0.2 vol% was confirmed in the experiment. When feed methane concentration was decreased from 0.8 vol% to 0.2 vol%, higher feed methane concentration was easier to intensify temperature nonuniformity. To restrain the increase of temperature asymmetry and nonuniformity, an electronically controlled adjustment was adopted. Valve opening ratio could be monitored to obtain more equivalent average temperature values of two sections of the packed bed. A 55-min process and a 116-min process were picked out from the cyclic steady-state period to eliminate temperature nonuniformity through adjusting valve opening ratio. As a result, the gaps in the high-temperature section width of two sections get narrowed and the average temperature of two sections is almost the same. The switching time ratio could be regulated to shift high-temperature cores of two sections to middle height position. A 58 min long process was selected with a switch time ratio of 1.25 and the temperature center height of both two sections dropped obviously. Synchronous adjustment of the valve opening ratio and the switching time ratio accelerated the adjustment process and double effects could be acquired in the meantime. A 36-min long process and a 28-min long process are chosen for simultaneous adjustment. The average temperature of two sections reach good agreement in the end and the temperature center height of two sections both drop obviously. This work is beneficial to the development of TFRR for better dealing with ventilation air methane and other lean gaseous fuel streams.

A Fast-Transient Response Digital Low-Dropout Regulator With Dual-Modes Tuning Technique

A fast transient response digital low dropout (LDO) regulator with a low quiescent current is proposed for power management applications in a self-powered wireless sensor system. The digital LDO incorporates both bisection method (BM) and steady-state tuning techniques to enhance the current efficiency and transient response speed. In steady-state period, the digital LDO works at steady-state mode and only one PMOS is switched at each clock edge for high accuracy and current efficiency. Once the variation of output voltage exceeds the detection boundaries, the BM mode is triggered and the required array conductance can be found in a short response time. The proposed digital LDO is fabricated using 65nm CMOS process. The measurement results show that with the load current switching between 0.1 mA and 4.5 mA, the proposed digital LDO shows a transient response time of 5.9 μs with a maximum undershoot voltage of 118 mV at a regulated output voltage of 0.55V. The current efficiency is 99.7% and the figure of merit is 62.2 ps.

Pressure distribution of a horizontal well in a bounded reservoir with constant pressure top and bottom

The purpose of this study is to develop a mathematical model using Source and Green’s functions for a Horizontal Wells in a Bounded Reservoir with Constant Pressure at the Top and Bottom for the interpretation of pressure responses in the reservoir based on dimensionless pressure and pressure derivative. Reservoir and well parameters investigated revealed what sets of reservoir/ well parameters combination that will prolong infinite activity of the reservoir before steady state sets in. Results show that dimensionless lateral extent does not directly affect the dimensionless pressure and dimensionless pressure derivative for very short well lengths as used in this paper. Dimensionless pressure increases with reservoir pay thickness and delay the time for steady state conditions. In fact external fluid invasion is strongly affected by the size of the pay thickness, thus the minimum time for steady state period to set in is according to the relation TD ≥ LD/5.&#x0D; Keywords: Bounded, reservoir, steady-state conditions, horizontal well, constant pressure.

РОЗВИТОК СПЕЦІАЛЬНОЇ ВИТРИВАЛОСТІ НА ОСНОВІ МОДЕЛЮВАННЯ ІГРОВОЇ ДІЯЛЬНОСТІ ФУТБОЛІСТІВ

The article considers new opportunities for special endurance development based on modeling playing activity of footballers. Objective. Experimentally test the effect of training session load on cardiorespiratory system response in the process of modeling playing activity of footballers. Methods. Modeling and monitoring of competitive activity. Determining the degree of tension of functional support using the calculated characteristics of the «training impulse». Results. Special modes of training work were applied, which simulate playing activity of two teams in the conditions of maintaining a stable state of cardiorespiratory system response. Evaluation and interpretation of indices are based on the characteristics of cardiorespiratory system response and its changes during the steady state period and during fatigue development. Changes in cardiorespiratory system response are shown in the process of registration and special processing of HR indices during the first to fourth six-minute halves of training work, which models playing game activity of footballers. The presented model of training session can be used in the process of increasing the endurance of footballers and for the current control of the functional support of special work capacity. The control is based on the assessment and interpretation of training impulse indices and its changes in the phase of steady state of footballers. Significant (p &lt; 0.05) decrease in the indices of training impulse registered during the second and fourth six-minute halves of training playing activity, as well as the increase in the range of individual differences of response indices are shown.

Coordinated Control Scheme of Battery Storage System to Augment LVRT Capability of SCIG-Based Wind Turbines and Frequency Regulation of Hybrid Power System

Fixed speed wind turbine-squirrel cage induction generator (FSWT-SCIG)-based wind farms (WFs) are increasing significantly. However, FSWT-SCIGs have no low voltage ride-through (LVRT) and frequency control capabilities, which creates a significant problem on power system transient and steady-state stability. This paper presents a new operational strategy to control the voltage and frequency of the entire power system, including large-scale FSWT-SCIG-based WFs, by using a battery storage system (BSS). The proposed cascaded control of the BSS is designed to provide effective quantity of reactive power during transient periods, to augment LVRT capability and real power during steady-state periods in order to damp frequency fluctuations. The cascaded control technique is built on four proportional integral (PI) controllers. The droop control technique is also adopted to ensure frequency control capability. Practical grid code is taken to demonstrate the LVRT capability. To evaluate the validity of the proposed system, simulation studies are executed on a reformed IEEE nine-bus power system with three synchronous generators (SGs) and SCIG-based WF with BSS. Triple-line-to-ground (3LG) and real wind speed data are used to analyze the hybrid power grid’s transient and steady-state stability. The simulation results indicate that the proposed system can be an efficient solution to stabilize the power system both in transient and steady-state conditions.

Increased minimum alveolar concentration-awake of Sevoflurane in women of breast surgery with sleep disorders

BackgroundSleep disorders are commonly encountered in clinic. Evidences showed that sleep deprivation may modulate the effectiveness of general anesthetics in rats. However, this phenomenon has not been explored in humans. The study aimed to investigate whether the hypnotic potency of sevoflurane in patients with sleep disorders differ from patients with normal sleep habits.MethodsWe recruited 44 patients scheduled for elective breast surgery and eventually analyzed 38 patients, including 19 subjects with normal sleep habits and 19 subjects with sleep disorders. According to the Dixon ‘up-and-down’ design, patients received sevoflurane at preselected concentrations starting at 1.0 vol%. After a steady-state period, a verbal command for testing awakening was performed. Based on the negative or positive response to the verbal command, we decreased or increased the concentration of sevoflurane by 0.2 vol% in the next patient accordingly. Plasma orexin-A was also measured before observation.ResultsThe MACawake of sevoflurane was 0.80% [95% confidence interval (CI), 0.683–0.926%] in the sleep disordered group vs 0.60% [95% CI, 0.493–0.689%] in the control group. The relative median potency between groups was 0.750 (95% CI, 0.236–0.969). Patients with sleep disorders had significantly higher orexin-A levels than control (72.17 ± 18.24 vs. 36.16 ± 14.18 pg/mL). A significant, positive relationship was detected between orexin-A level and probability of awakening (OR = 1.081, 95% CI is 1.020–1.146, P = 0.008).ConclusionsMACawake of sevoflurane is higher in mild-aged women of breast surgery with sleep disorders compared to those with normal sleep habits. The increased anesthetic requirement may be related to changes of orexin-A levels. These findings suggest that sleep may have a potential impact on clinical anesthesia, including changes of sensitivity to anesthetics or postoperative complications. Further research is needed to confirm this hypothesis.Clinical trial registrationChinese Clinical Trial Registry (ChiCTR1800016022), date of registration 07 May 2018.

Simultaneous Removal of Hexane and Ethanol from Air in a Biotrickling Filter—Process Performance and Monitoring Using Electronic Nose

Biofiltration is a well-accepted method for the removal of malodorous compounds from air streams. Interestingly, the mechanisms underlying this process are not fully understood. The aim of this paper was to investigate the simultaneous removal of hydrophobic hexane with hydrophilic ethanol, resulting in the enhanced removal of hexane in the presence of ethanol. Investigations were performed in a peat-perlite packed biotrickling filter and the process performance was monitored using both gas chromatography and electronic nose techniques. The results indicate that the length as well as the efficiency of biofiltration during the start-up period depend on the feed composition, with higher efficiency obtained when hexane and ethanol were fed together from the process initiation. The experiments in the steady-state period present the biofilter performance when different ratios of hydrophilic to hydrophobic compounds were fed to the biofilter. The obtained results show the synergistic effects of the addition of a hydrophilic compound on the removal efficiency of hydrophobic hexane. The influence of the ratio of hydrophilic to hydrophobic compounds is discussed in terms of enhancing the mass transfer phenomena for hydrophobic volatile organic compounds.

Convolutional Neural Network-Based Inter-Turn Fault Diagnosis in LSPMSMs

Stator inter-turn fault diagnosis system for electric motors is of a considerable concern due to its significant effect on industrial production. In this paper, a new method for detecting the inter-turn fault and quantifying its severity in the line start permanent magnet synchronous motor (LSMPSM) is proposed. The new method depends on monitoring the stator current during steady-state period to detect the fault. The convolutional neural network (CNN) method is proposed to correlate the motor steady-state current with the status of the motor winding conditions and detect any presence of inter-turn faults. The data used in this study is extracted from both an experimental setup of a one-horsepower LSPMSM and the corresponding verified mathematical model through several testing cases under various loading conditions. One of the main features of the proposed technique is that it does not require separate feature extraction phase. The results indicate that the proposed technique is able to detect the inter-turn fault under different loading conditions varies from 0NM to 4NM with accuracy of 97.75% for all defined fault levels. The use of steady-state current for fault detection regardless of motor load enables the proposed technique to detect the fault online without disturbing the system functionality and reliability as well as without adding any extra hardware to the system.

Sodium and nitrate favor the steady state of cyanobacteria in a semiarid ecosystem

This study characterized steady state events (SS) in a semiarid reservoir (Brazil) dominated by cyanobacteria for 130 weeks, and evaluated the influence of different abiotic variables on their occurrence. It was hypothesized that, in semiarid reservoirs, steady state events are independent from seasonality and influenced by high nutrient concentrations, and steady state periods show low variation of species. Our data revealed the occurrence of SS events in both the dry and wet seasons. Higher concentrations of nitrate and sodium together with higher values of color favored the development of SS. Species composing the SS dominated by Microcystis aeruginosa (Kützing) Kützing was correlated with higher sulfate concentrations, while higher values of turbidity and sodium concentrations favored the SS of Cylindrospermopsis raciborskii (Woloszynska) Seenaya and Suba Raju and Planktothrix agardhii (Gomont) Anagnostidis and Komárek. The results supported the hypothesis and showed the importance of variables rarely evaluated in works of this nature, such as sodium and sulfate in SS establishment of cyanobacteria.

Transition from Self-Organized Criticality into Self-Organization during Sliding Si3N4 Balls against Nanocrystalline Diamond Films

The paper investigates the variation of friction force (Fx) during reciprocating sliding tests on nanocrystalline diamond (NCD) films. The analysis of the friction behavior during the run-in period is the focus of the study. The NCD films were grown using microwave plasma-enhanced chemical vapor deposition (MW-PECVD) on single-crystalline diamond SCD(110) substrates. Reciprocating sliding tests were conducted under 500 and 2000 g of normal load using Si3N4 balls as a counter body. The friction force permanently varies during the test, namely Fx value can locally increase or decrease in each cycle of sliding. The distribution of friction force drops (dFx) was extracted from the experimental data using a specially developed program. The analysis revealed a power-law distribution f−µ of dFx for the early stage of the run-in with the exponent value (µ) in the range from 0.6 to 2.9. In addition, the frequency power spectrum of Fx time series follows power-law distribution f−α with α value in the range of 1.0–2.0, with the highest values (1.6–2.0) for the initial stage of the run-in. No power-law distribution of dFx was found for the later stage of the run-in and the steady-state periods of sliding with the exception for periods where a relatively extended decrease of coefficient of friction (COF) was observed. The asperity interlocking leads to the stick-slip like sliding at the early stage of the run-in. This tribological behavior can be related to the self-organized criticality (SOC). The emergence of dissipative structures at the later stages of the run-in, namely the formation of ripples, carbonaceous tribolayer, etc., can be associated with the self-organization (SO).

Evaluation of least significant changes of pulse contour analysis-derived parameters

BackgroundMany maneuvers assessing fluid responsiveness (minifluid challenge, lung recruitment maneuver, end-expiratory occlusion test, passive leg raising) are considered as positive when small variations in cardiac index, stroke volume index, stroke volume variation or pulse pressure variation occur. Pulse contour analysis allows continuous and real-time cardiac index, stroke volume, stroke volume variation and pulse pressure variation estimations. To use these maneuvers with pulse contour analysis, the knowledge of the minimal change that needs to be measured by a device to recognize a real change (least significant change) has to be studied. The aim of this study was to evaluate the least significant change of cardiac index, stroke volume index, stroke volume variation and pulse pressure variation obtained using pulse contour analysis (ProAQT®, Pulsion Medical System, Germany).MethodsIn this observational study, we included 50 mechanically ventilated patients undergoing neurosurgery in the operating room. Cardiac index, stroke volume index, pulse pressure variation and stroke volume variation obtained using ProAQT® (Pulsion Medical System, Germany) were recorded every 12 s during 15-min steady-state periods. Least significant changes were calculated every minute.ResultsLeast significant changes statistically differed over time for cardiac index, stroke volume index, pulse pressure variation and stroke volume variation (p < 0.001). Least significant changes ranged from 1.3 to 0.7% for cardiac index, from 1.3 to 0.8% for stroke volume index, from 10 to 4.9% for pulse pressure variation and from 10.8 to 4.3% for stroke volume variation.ConclusionTo conclude, the present study suggests that pulse contour analysis is able to detect rapid and small changes in cardiac index and stroke volume index, but the interpretation of rapid and small changes of pulse pressure variation and stroke volume variation must be done with caution.

Serum and peritoneal exudate concentrations after high doses of β-lactams in critically ill patients with severe intra-abdominal infections: an observational prospective study.

Critically ill patients with severe intra-abdominal infections (IAIs) requiring surgery may undergo several pharmacokinetic (PK) alterations that can lead to β-lactam underdosage. To measure serum and peritoneal exudate concentrations of β-lactams after high doses and optimal administration schemes. This observational prospective study included critically ill patients with suspicion of IAI who required surgery and a β-lactam antibiotic as empirical therapy. Serum and peritoneal exudate concentrations were measured during surgery and after a 24 h steady-state period. The PK/pharmacodynamic (PD) target was to obtain serum β-lactam concentrations of 100% fT>4×MIC based on a worst-case scenario (based on the EUCAST highest epidemiological cut-off values) before bacterial documentation (a priori) and redefined following determination of the MIC for the isolated bacteria (a posteriori). Registered with ClinicalTrials.gov (NCT03310606). Forty-eight patients were included with a median (IQR) age of 64 (53-74) years and a SAPS II of 40 (32-65). The main diagnosis was secondary nosocomial peritonitis. Piperacillin/tazobactam was the most administered β-lactam antibiotic (75%). The serum/peritoneal piperacillin/tazobactam ratio was 0.88 (0.64-0.97) after a 24 h steady-state period. Prior to bacterial documentation, 16 patients (33.3%) achieved the a priori PK/PD target. The identification of microorganisms was available for 34 patients (71%). Based on the MIC for isolated bacteria, 78% of the patients achieved the serum PK/PD target. In severe IAIs, high doses of β-lactams ensured 100% fT>4×MIC in the serum for 78% of critically ill patients with severe IAIs within the first 24 h. In order to define optimal β-lactam dosing, the PK/PD target should take into account the tissue penetration and local ecology.

Novel Fault Models for Electronically Coupled Distributed Energy Resources and Their Laboratory Validation

In this paper, novel models for electronically coupled distributed energy resources (ECDERs) for online fault calculations of large-scale systems are proposed. ECDERs have different fault responses than traditional synchronous and induction (AC) machines, and generally accepted models for these emerging DERs do not exist. The deployment of ECDERs is constantly increasing worldwide and there is an urgent need for developing appropriate models for fault calculations. In order to have fast calculations, applicable to large-scale systems, the dynamic behavior of traditional AC machines have been approximated in three steady state time-periods (sub-transient, transient, and steady-state). Accordingly, the online fault calculations of large-scale systems have been conducted for these three periods. To simulate the ECDERs’ dynamic behavior, and develop models that are compliant with traditional fault calculations, fault models of ECDERs in the sub-transient, transient, and steady-state periods are proposed, with a short peak current period included in the proposed models during the sub-transient period. To validate the proposed models, they are integrated into recently developed online fault calculations, and tested on various large-scale systems. Results from computer simulations are compared with results obtained using state-of-the-art laboratory equipment, as well as with relevant reports on fault current contributions of ECDERs. The results match very well, further validating the proposed models.

Dynamic pore network modelling of real gas transport in shale nanopore structure

Gas transport in shale nanopores is controlled by the complex transport mechanisms and pore structure characteristics. So far much work has been done on the single pore and regular structure based pore network but little is known on real gas transport behavior on a realistic shale pore structure model. In this work, a dynamic pore network model is proposed to describe single component methane transport in nano-scale porous media. Gas transport behavior takes transport mechanisms of slip flow, transition flow, surface diffusion and ad/desorption into account. Real gas effect under high pressure and temperature is considered when calculating gas properties. A three dimensional pore network model is built from a three dimensional image that is reconstructed using multi-point statistics from a small organic-rich area on a two dimensional shale SEM image. This pore network model is used to analyze dynamic gas transport and pressure drop transmission process. Our simulated results reveal that there exists a time period that gas permeability on the pore network is influenced by the pressure drop transmission process and pore structure that flows on. When pressure drop reaches outlet, gas transport turns steady state. At steady state period gas permeability becomes constant and is influenced by the effective stress, pressure, temperature and shale rock property.

Modelling and Design of Five Parameter Single Diode Photovoltaic Model with Artificial Intelligent MPPT Power System

In this article, an improved single diode Photo Voltaic mathematical system with novel Fuzzy Logic Control (FLC) based maximum power extraction approach was developed. The photovoltaic module voltage versus current characteristics derivation were developed and it’s utilized to extract the photovoltaic module unknown arguments via as saturation current, light generated current, shunt and ideality factor, series resistance at reference. The various mathematical models are utilized to determine the photovoltaic system arguments at reference circumference by acquainting equations to calculate the value of resistance in series and shunt. The production of highest power of PV modules were equated with dissimilar manufactured PV model with various environmental conditions. The percentage relative error and highest power is computed and compared with previous models in the survey for dissimilar photovoltaic modules. Further, in this paper added with improved Perturb and Observe (P&amp;O) based FLC control approach utilized to extract the highest energy from solar panel. The output of the developed system exposes the good performance during steady state period and transient periods. Moreover to confirm the developed photovoltaic model matches exactly with that of Sandia PV module.

Motion direction representation in multivariate electroencephalography activity for smooth pursuit eye movements

Visually-guided smooth pursuit eye movements are composed of initial open-loop and later steady-state periods. Feedforward sensory information dominates the motor behavior during the open-loop pursuit, and a more complex feedback loop regulates the steady-state pursuit. To understand the neural representations of motion direction during open-loop and steady-state smooth pursuits, we recorded electroencephalography (EEG) responses from human observers while they tracked random-dot kinematograms as pursuit targets. We estimated population direction tuning curves from multivariate EEG activity using an inverted encoding model. We found significant direction tuning curves as early as about 60 ms from stimulus onset. Direction tuning responses were generalized to later times during the open-loop smooth pursuit, but they became more dynamic during the later steady-state pursuit. The encoding quality of retinal motion direction information estimated from the early direction tuning curves was predictive of trial-by-trial variation in initial pursuit directions. These results suggest that the movement directions of open-loop smooth pursuit are guided by the representation of the retinal motion present in the multivariate EEG activity.