Power factor improvement in three-phase networks with unbalanced inductive loads using the Roederstein ESTAmat RPR power factor controller

NASA Astrophysics Data System (ADS)

Diniş, C. M.; Cunţan, C. D.; Rob, R. O. S.; Popa, G. N.

2018-01-01

The paper presents the analysis of a power factor with capacitors banks, without series coils, used for improving power factor for a three-phase and single-phase inductive loads. In the experimental measurements, to improve the power factor, the Roederstein ESTAmat RPR power factor controller can command up to twelve capacitors banks, while experimenting using only six capacitors banks. Six delta capacitors banks with approximately equal reactive powers were used for experimentation. The experimental measurements were carried out with a three-phase power quality analyser which worked in three cases: a case without a controller with all capacitors banks permanently parallel connected with network, and two other cases with power factor controller (one with setting power factor at 0.92 and the other one at 1). When performing experiments with the power factor controller, a current transformer was used to measure the current on one phase (at a more charged or less loaded phase).

Structural Pain Compensating Flight Control

NASA Technical Reports Server (NTRS)

Miller, Chris J.

2014-01-01

The problem of control command and maneuver induced structural loads is an important aspect of any control system design. Designers must design the aircraft structure and the control architecture to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to build the structure with high margins, restrict control surface commands to known good combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage.

NWTC Researchers Field-Test Advanced Control Turbine Systems to Increase Performance, Decrease Structural Loading of Wind Turbines and Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Researchers at the National Renewable Energy Laboratory's (NREL's) National Wind Technology Center (NWTC) are studying component controls, including new advanced actuators and sensors, for both conventional turbines as well as wind plants. This research will help develop innovative control strategies that reduce aerodynamic structural loads and improve performance. Structural loads can cause damage that increase maintenance costs and shorten the life of a turbine or wind plant.

LPV control for the full region operation of a wind turbine integrated with synchronous generator.

PubMed

Cao, Guoyan; Grigoriadis, Karolos M; Nyanteh, Yaw D

2015-01-01

Wind turbine conversion systems require feedback control to achieve reliable wind turbine operation and stable current supply. A robust linear parameter varying (LPV) controller is proposed to reduce the structural loads and improve the power extraction of a horizontal axis wind turbine operating in both the partial load and the full load regions. The LPV model is derived from the wind turbine state space models extracted by FAST (fatigue, aerodynamics, structural, and turbulence) code linearization at different operating points. In order to assure a smooth transition between the two regions, appropriate frequency-dependent varying scaling parametric weighting functions are designed in the LPV control structure. The solution of a set of linear matrix inequalities (LMIs) leads to the LPV controller. A synchronous generator model is connected with the closed LPV control loop for examining the electrical subsystem performance obtained by an inner speed control loop. Simulation results of a 1.5 MW horizontal axis wind turbine model on the FAST platform illustrates the benefit of the LPV control and demonstrates the advantages of this proposed LPV controller, when compared with a traditional gain scheduling PI control and prior LPV control configurations. Enhanced structural load mitigation, improved power extraction, and good current performance were obtained from the proposed LPV control.

LPV Control for the Full Region Operation of a Wind Turbine Integrated with Synchronous Generator

PubMed Central

Grigoriadis, Karolos M.; Nyanteh, Yaw D.

2015-01-01

Wind turbine conversion systems require feedback control to achieve reliable wind turbine operation and stable current supply. A robust linear parameter varying (LPV) controller is proposed to reduce the structural loads and improve the power extraction of a horizontal axis wind turbine operating in both the partial load and the full load regions. The LPV model is derived from the wind turbine state space models extracted by FAST (fatigue, aerodynamics, structural, and turbulence) code linearization at different operating points. In order to assure a smooth transition between the two regions, appropriate frequency-dependent varying scaling parametric weighting functions are designed in the LPV control structure. The solution of a set of linear matrix inequalities (LMIs) leads to the LPV controller. A synchronous generator model is connected with the closed LPV control loop for examining the electrical subsystem performance obtained by an inner speed control loop. Simulation results of a 1.5 MW horizontal axis wind turbine model on the FAST platform illustrates the benefit of the LPV control and demonstrates the advantages of this proposed LPV controller, when compared with a traditional gain scheduling PI control and prior LPV control configurations. Enhanced structural load mitigation, improved power extraction, and good current performance were obtained from the proposed LPV control. PMID:25884036

Effect of counter-pulsation control of a pulsatile left ventricular assist device on working load variations of the native heart.

PubMed

Choi, Seong Wook; Nam, Kyoung Won; Lim, Ki Moo; Shim, Eun Bo; Won, Yong Soon; Woo, Heung Myong; Kwak, Ho Hyun; Noh, Mi Ryoung; Kim, In Young; Park, Sung Min

2014-04-03

When using a pulsatile left ventricular assist device (LVAD), it is important to reduce the cardiac load variations of the native heart because severe cardiac load variations can induce ventricular arrhythmia. In this study, we investigated the effect of counter-pulsation control of the LVAD on the reduction of cardiac load variation. A ventricular electrocardiogram-based counter-pulsation control algorithm for a LVAD was implemented, and the effects of counter-pulsation control of the LVAD on the reduction of the working load variations of the left ventricle were determined in three animal experiments. Deviations of the working load of the left ventricle were reduced by 51.3%, 67.9%, and 71.5% in each case, and the beat-to-beat variation rates in the working load were reduced by 84.8%, 82.7%, and 88.2% in each ease after counter-pulsation control. There were 3 to 12 premature ventricle contractions (PVCs) before counter-pulsation control, but no PVCs were observed during counter-pulsation control. Counter-pulsation control of the pulsatile LVAD can reduce severe cardiac load variations, but the average working load is not markedly affected by application of counter-pulsation control because it is also influenced by temporary cardiac outflow variations. We believe that counter-pulsation control of the LVAD can improve the long-term safety of heart failure patients equipped with LVADs.

Solar Dynamic Power System Stability Analysis and Control

NASA Technical Reports Server (NTRS)

Momoh, James A.; Wang, Yanchun

1996-01-01

The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.

Performance Evaluation of UPQC under Nonlinear Unbalanced Load Conditions Using Synchronous Reference Frame Based Control

NASA Astrophysics Data System (ADS)

Kota, Venkata Reddy; Vinnakoti, Sudheer

2017-12-01

Today, maintaining Power Quality (PQ) is very important in the growing competent world. With new equipments and devices, new challenges are also being put before power system operators. Unified Power Quality Conditioner (UPQC) is proposed to mitigate many power quality problems and to improve the performance of the power system. In this paper, an UPQC with Fuzzy Logic controller for capacitor voltage balancing is proposed in Synchronous Reference Frame (SRF) based control with Modified Phased Locked Loop (MPLL). The proposed controller with SRF-MPLL based control is tested under non-linear and unbalanced load conditions. The system is developed in Matlab/Simulink and its performance is analyzed under various conditions like non-linear, unbalanced load and polluted supply voltage including voltage sag/swells. Active and reactive power flow in the system, power factor and %THD of voltages and currents before and after compensation are also analyzed in this work. Results prove the applicability of the proposed scheme for power quality improvement. It is observed that the fuzzy controller gives better performance than PI controller with faster capacitor voltage balancing and also improves the dynamic performance of the system.

Effects of running with backpack loads during simulated gravitational transitions: Improvements in postural control

NASA Astrophysics Data System (ADS)

Brewer, Jeffrey David

The National Aeronautics and Space Administration is planning for long-duration manned missions to the Moon and Mars. For feasible long-duration space travel, improvements in exercise countermeasures are necessary to maintain cardiovascular fitness, bone mass throughout the body and the ability to perform coordinated movements in a constant gravitational environment that is six orders of magnitude higher than the "near weightlessness" condition experienced during transit to and/or orbit of the Moon, Mars, and Earth. In such gravitational transitions feedback and feedforward postural control strategies must be recalibrated to ensure optimal locomotion performance. In order to investigate methods of improving postural control adaptation during these gravitational transitions, a treadmill based precision stepping task was developed to reveal changes in neuromuscular control of locomotion following both simulated partial gravity exposure and post-simulation exercise countermeasures designed to speed lower extremity impedance adjustment mechanisms. The exercise countermeasures included a short period of running with or without backpack loads immediately after partial gravity running. A novel suspension type partial gravity simulator incorporating spring balancers and a motor-driven treadmill was developed to facilitate body weight off loading and various gait patterns in both simulated partial and full gravitational environments. Studies have provided evidence that suggests: the environmental simulator constructed for this thesis effort does induce locomotor adaptations following partial gravity running; the precision stepping task may be a helpful test for illuminating these adaptations; and musculoskeletal loading in the form of running with or without backpack loads may improve the locomotor adaptation process.

An improved sample loading technique for cellular metabolic response monitoring under pressure

NASA Astrophysics Data System (ADS)

Gikunda, Millicent Nkirote

To monitor cellular metabolism under pressure, a pressure chamber designed around a simple-to-construct capillary-based spectroscopic chamber coupled to a microliter-flow perfusion system is used in the laboratory. Although cyanide-induced metabolic responses from Saccharomyces cerevisiae (baker's yeast) could be controllably induced and monitored under pressure, previously used sample loading technique was not well controlled. An improved cell-loading technique which is based on use of a secondary inner capillary into which the sample is loaded then inserted into the capillary pressure chamber, has been developed. As validation, we demonstrate the ability to measure the chemically-induced metabolic responses at pressures of up to 500 bars. This technique is shown to be less prone to sample loss due to perfusive flow than the previous techniques used.

Application of interleaved flyback micro inverter in a grid connected system

NASA Astrophysics Data System (ADS)

Brindha, R.; Ananthichristy, A.; Poornima, P. U.; Madhana, M.; Ashok Rathish, S.; Ragavi, Selvam

2018-04-01

The two control strategies CCM and DCM have various effects on the loss distribution and efficiency and thus were studied for the interleaved flyback micro inverter concentrating on the loss analysis under different load conditions. The dominant losses with heavy load include the conduction loss and the transformer loss in case of the interleaved flyback micro inverter; whereas driving of gate loss, the turn-off loss in the transformer core loss and in the powermosfets are included in the dominant losses with light load. A new hybrid control strategy which has the one-phase DCM and two-phase DCM control reduces the dominant losses in order to improving the efficiency based on the load in wide load range is proposed here.

Application of winglets and/or wing tip extensions with active load control on the Boeing 747

NASA Technical Reports Server (NTRS)

Allison, R. L.; Perkin, B. R.; Schoenman, R. L.

1978-01-01

The application of wing tip modifications and active control technology to the Boeing 747 airplane for the purpose of improving fuel efficiency is considered. Wing tip extensions, wing tip winglets, and the use of the outboard ailerons for active wing load alleviation are described. Modest performance improvements are indicated. A costs versus benefits approach is taken to decide which, if any, of the concepts warrant further development and flight test leading to possible incorporation into production airplanes.

Multimodal nanoporous silica nanoparticles functionalized with aminopropyl groups for improving loading and controlled release of doxorubicin hydrochloride.

PubMed

Wang, Xin; Li, Chang; Fan, Na; Li, Jing; He, Zhonggui; Sun, Jin

2017-09-01

The purpose of this study was to develop amino modified multimodal nanoporous silica nanoparticles (M-NSNs-NH 2 ) loaded with doxorubicin hydrochloride (DOX), intended to enhance the drug loading capacity and to achieve controlled release effect. M-NSNs were functionalized with aminopropyl groups through post-synthesis. The contribution of large pore sizes and surface chemical groups on DOX loading and release were systemically studied using transmission electron microscope (TEM), nitrogen adsorption/desorption measurement, Fourier transform infrared spectroscopy (FTIR), zeta potential analysis, X-ray photoelectron spectroscopy (XPS) and ultraviolet spectrophotometer (UV). The results demonstrated that the NSNs were functionalized with aminopropyl successfully and the DOX molecules were adsorbed inside the nanopores by the hydrogen bonding. The release performance indicated that DOX loaded M-NSNs significantly controlled DOX release, furthermore DOX loaded M-NSNs-NH 2 performed slower controlled release, which was mainly attributed to its stronger hydrogen bonding forces. As expected, we developed a novel carrier with high drug loading capacity and controlled release for DOX. Copyright © 2017 Elsevier B.V. All rights reserved.

Technical Study on Improvement of Endurance Capability of Limit Short-circuit Current of Charge Control SMART Meter

NASA Astrophysics Data System (ADS)

Li, W. W.; Du, Z. Z.; Yuan, R. m.; Xiong, D. Z.; Shi, E. W.; Lu, G. N.; Dai, Z. Y.; Chen, X. Q.; Jiang, Z. Y.; Lv, Y. G.

2017-10-01

Smart meter represents the development direction of energy-saving smart grid in the future. The load switch, one of the core parts of smart meter, should be of high reliability, safety and endurance capability of limit short-circuit current. For this reason, this paper discusses the quick simulation of relationship between attraction and counterforce of load switch without iteration, establishes dual response surface model of attraction and counterforce and optimizes the design scheme of load switch for charge control smart meter, thus increasing electromagnetic attraction and spring counterforce. In this way, this paper puts forward a method to improve the withstand capacity of limit short-circuit current.

NCHRP project 20-07/task 361 : hamburg wheel-track test equipment requirements and improvements to AASHTO T 324 : research project capsule.

DOT National Transportation Integrated Search

2015-02-01

The Loaded Wheel Test (LWT) is a laboratory-controlled rut depth test that uses loaded wheel(s) : to apply a moving load on hot-mix and warm-mix asphalt (HMA and WMA) specimens to simulate : tra c load applied on asphalt pavements. In the 1970s He...

Nonlinear engine model for idle speed control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Livshiz, M.; Sanvido, D.J.; Stiles, S.D.

1994-12-31

This paper describes a nonlinear model of an engine used for the design of idle speed control and prediction in a broad range of idle speeds and operational conditions. Idle speed control systems make use of both spark advance and the idle air actuator to control engine speed for improved response relative to variations in the target idle speed due to load disturbances. The control system at idle can be presented by a multiple input multiple output (MIMO) nonlinear model. Information of nonlinearities helps to improve performance of the system over the whole range of engine speeds. A proposed simplemore » nonlinear model of the engine at idle was applied for design of optimal controllers and predictors for improved steady state, load rejection and transition from and to idle. This paper describes vehicle results of engine speed prediction based on the described model.« less

Climate Control Load Reduction Strategies for Electric Drive Vehicles in Cold Weather

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeffers, Matthew A.; Chaney, Larry; Rugh, John P.

When operated, the climate control system is the largest auxiliary load on a vehicle. This load has significant impact on fuel economy for conventional and hybrid vehicles, and it drastically reduces the driving range of all electric vehicles (EVs). Heating is even more detrimental to EV range than cooling because no engine waste heat is available. Reducing the thermal loads on the heating, ventilating, and air conditioning system will extend driving range and increase the market penetration of EVs. Researchers at the National Renewable Energy Laboratory have evaluated strategies for vehicle climate control load reduction with special attention toward gridmore » connected electric vehicles. Outdoor vehicle thermal testing and computational modeling were used to assess potential strategies for improved thermal management and to evaluate the effectiveness of thermal load reduction technologies. A human physiology model was also used to evaluate the impact on occupant thermal comfort. Experimental evaluations of zonal heating strategies demonstrated a 5.5% to 28.5% reduction in cabin heating energy over a 20-minute warm-up. Vehicle simulations over various drive cycles show a 6.9% to 18.7% improvement in EV range over baseline heating using the most promising zonal heating strategy investigated. A national-level analysis was conducted to determine the overall national impact. If all vehicles used the best zonal strategy, the range would be improved by 7.1% over the baseline heating range. This is a 33% reduction in the range penalty for heating.« less

Climate Control Load Reduction Strategies for Electric Drive Vehicles in Cold Weather: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeffers, Matthew; Chaney, Lawrence; Rugh, John

When operated, the climate control system is the largest auxiliary load on a vehicle. This load has significant impact on fuel economy for conventional and hybrid vehicles, and it drastically reduces the driving range of all electric vehicles (EVs). Heating is even more detrimental to EV range than cooling because no engine waste heat is available. Reducing the thermal loads on the heating, ventilating, and air conditioning system will extend driving range and increase the market penetration of EVs. Researchers at the National Renewable Energy Laboratory have evaluated strategies for vehicle climate control load reduction with special attention toward gridmore » connected electric vehicles. Outdoor vehicle thermal testing and computational modeling were used to assess potential strategies for improved thermal management and to evaluate the effectiveness of thermal load reduction technologies. A human physiology model was also used to evaluate the impact on occupant thermal comfort. Experimental evaluations of zonal heating strategies demonstrated a 5.5% to 28.5% reduction in cabin heating energy over a 20-minute warm-up. Vehicle simulations over various drive cycles show a 6.9% to 18.7% improvement in EV range over baseline heating using the most promising zonal heating strategy investigated. A national-level analysis was conducted to determine the overall national impact. If all vehicles used the best zonal strategy, the range would be improved by 7.1% over the baseline heating range. This is a 33% reduction in the range penalty for heating.« less

Improving Middle School Students’ Critical Thinking Skills Through Reading Infusion-Loaded Discovery Learning Model in the Science Instruction

NASA Astrophysics Data System (ADS)

Nuryakin; Riandi

2017-02-01

A study has been conducted to obtain a depiction of middle school students’ critical thinking skills improvement through the implementation of reading infusion-loaded discovery learning model in science instruction. A quasi-experimental study with the pretest-posttest control group design was used to engage 55 eighth-year middle school students in Tasikmalaya, which was divided into the experimental and control group respectively were 28 and 27 students. Critical thinking skills were measured using a critical thinking skills test in multiple-choice with reason format questions that administered before and after a given instruction. The test was 28 items encompassing three essential concepts, vibration, waves and auditory senses. The critical thinking skills improvement was determined by using the normalized gain score and statistically analyzed by using Mann-Whitney U test.. The findings showed that the average of students’ critical thinking skills normalized gain score of both groups were 59 and 43, respectively for experimental and control group in the medium category. There were significant differences between both group’s improvement. Thus, the implementation of reading infusion-loaded discovery learning model could further improve middle school students’ critical thinking skills than conventional learning.

Stabilization of a Quadrotor With Uncertain Suspended Load Using Sliding Mode Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Xu; Liu, Rui; Zhang, Jiucai

2016-08-21

The stability and trajectory control of a quadrotor carrying a suspended load with a fixed known mass has been extensively studied in recent years. However, the load mass is not always known beforehand in practical applications. This mass uncertainty brings uncertain disturbances to the quadrotor system, causing existing controllers to have a worse performance or to be collapsed. To improve the quadrotor's stability in this situation, we investigate the impacts of the uncertain load mass on the quadrotor. By comparing the simulation results of two controllers -- the proportional-derivative (PD) controller and the sliding mode controller (SMC) driven by amore » sliding mode disturbance of observer (SMDO), the quadrotor's performance is verified to be worse as the uncertainty increases. The simulation results also show a controller with stronger robustness against disturbances is better for practical applications.« less

An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions.

PubMed

Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M

2017-01-01

In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method.

An improved synchronous reference frame current control strategy for a photovoltaic grid-connected inverter under unbalanced and nonlinear load conditions

PubMed Central

Naderipour, Amirreza; Asuhaimi Mohd Zin, Abdullah; Bin Habibuddin, Mohd Hafiz; Miveh, Mohammad Reza; Guerrero, Josep M.

2017-01-01

In recent years, renewable energy sources have been considered the most encouraging resources for grid and off-grid power generation. This paper presents an improved current control strategy for a three-phase photovoltaic grid-connected inverter (GCI) under unbalanced and nonlinear load conditions. It is challenging to suppress the harmonic content in the output current below a pre-set value in the GCI. It is also difficult to compensate for unbalanced loads even when the grid is under disruption due to total harmonic distortion (THD) and unbalanced loads. The primary advantage and objective of this method is to effectively compensate for the harmonic current content of the grid current and microgrid without the use of any compensation devices, such as active and passive filters. This method leads to a very low THD in both the GCI currents and the current exchanged with the grid. The control approach is designed to control the active and reactive power and harmonic current compensation, and it also corrects the system unbalance. The proposed control method features the synchronous reference frame (SRF) method. Simulation results are presented to demonstrate the effective performance of the proposed method. PMID:28192436

The effect of implementing cognitive load theory-based design principles in virtual reality simulation training of surgical skills: a randomized controlled trial.

PubMed

Andersen, Steven Arild Wuyts; Mikkelsen, Peter Trier; Konge, Lars; Cayé-Thomasen, Per; Sørensen, Mads Sølvsten

2016-01-01

Cognitive overload can inhibit learning, and cognitive load theory-based instructional design principles can be used to optimize learning situations. This study aims to investigate the effect of implementing cognitive load theory-based design principles in virtual reality simulation training of mastoidectomy. Eighteen novice medical students received 1 h of self-directed virtual reality simulation training of the mastoidectomy procedure randomized for standard instructions (control) or cognitive load theory-based instructions with a worked example followed by a problem completion exercise (intervention). Participants then completed two post-training virtual procedures for assessment and comparison. Cognitive load during the post-training procedures was estimated by reaction time testing on an integrated secondary task. Final-product analysis by two blinded expert raters was used to assess the virtual mastoidectomy performances. Participants in the intervention group had a significantly increased cognitive load during the post-training procedures compared with the control group (52 vs. 41 %, p  = 0.02). This was also reflected in the final-product performance: the intervention group had a significantly lower final-product score than the control group (13.0 vs. 15.4, p  < 0.005). Initial instruction using worked examples followed by a problem completion exercise did not reduce the cognitive load or improve the performance of the following procedures in novices. Increased cognitive load when part tasks needed to be integrated in the post-training procedures could be a possible explanation for this. Other instructional designs and methods are needed to lower the cognitive load and improve the performance in virtual reality surgical simulation training of novices.

Aerodynamic load control strategy of wind turbine in microgrid

NASA Astrophysics Data System (ADS)

Wang, Xiangming; Liu, Heshun; Chen, Yanfei

2017-12-01

A control strategy is proposed in the paper to optimize the aerodynamic load of the wind turbine in micro-grid. In grid-connection mode, the wind turbine adopts a new individual variable pitch control strategy. The pitch angle of the blade is rapidly given by the controller, and the pitch angle of each blade is fine tuned by the weight coefficient distributor. In islanding mode, according to the requirements of energy storage system, a given power tracking control method based on fuzzy PID control is proposed. Simulation result shows that this control strategy can effectively improve the axial aerodynamic load of the blade under rated wind speed in grid-connection mode, and ensure the smooth operation of the micro-grid in islanding mode.

Control method of Three-phase Four-leg converter based on repetitive control

NASA Astrophysics Data System (ADS)

Hui, Wang

2018-03-01

The research chose the magnetic levitation force of wind power generation system as the object. In order to improve the power quality problem caused by unbalanced load in power supply system, we combined the characteristics and repetitive control principle of magnetic levitation wind power generation system, and then an independent control strategy for three-phase four-leg converter was proposed. In this paper, based on the symmetric component method, the second order generalized integrator was used to generate the positive and negative sequence of signals, and the decoupling control was carried out under the synchronous rotating reference frame, in which the positive and negative sequence voltage is PI double closed loop, and a PI regulator with repetitive control was introduced to eliminate the static error regarding the fundamental frequency fluctuation characteristic of zero sequence component. The simulation results based on Matlab/Simulink show that the proposed control project can effectively suppress the disturbance caused by unbalanced loads and maintain the load voltage balance. The project is easy to be achieved and remarkably improves the quality of the independent power supply system.

Analysis of rotor vibratory loads using higher harmonic pitch control

NASA Technical Reports Server (NTRS)

Quackenbush, Todd R.; Bliss, Donald B.; Boschitsch, Alexander H.; Wachspress, Daniel A.

1992-01-01

Experimental studies of isolated rotors in forward flight have indicated that higher harmonic pitch control can reduce rotor noise. These tests also show that such pitch inputs can generate substantial vibratory loads. The modification is summarized of the RotorCRAFT (Computation of Rotor Aerodynamics in Forward flighT) analysis of isolated rotors to study the vibratory loading generated by high frequency pitch inputs. The original RotorCRAFT code was developed for use in the computation of such loading, and uses a highly refined rotor wake model to facilitate this task. The extended version of RotorCRAFT incorporates a variety of new features including: arbitrary periodic root pitch control; computation of blade stresses and hub loads; improved modeling of near wake unsteady effects; and preliminary implementation of a coupled prediction of rotor airloads and noise. Correlation studies are carried out with existing blade stress and vibratory hub load data to assess the performance of the extended code.

Acute effects of a loaded warm-up protocol on change of direction speed in professional badminton players.

PubMed

Maloney, Sean J; Turner, Anthony N; Miller, Stuart

2014-10-01

It has previously been shown that a loaded warm-up may improve power performances. We examined the acute effects of loaded dynamic warm-up on change of direction speed (CODS), which had not been previously investigated. Eight elite badminton players participated in three sessions during which they performed vertical countermovement jump and CODS tests before and after undertaking the dynamic warm-up. The three warm-up conditions involved wearing a weighted vest (a) equivalent to 5% body mass, (b) equivalent to 10% body mass, and (c) a control where a weighted vest was not worn. Vertical jump and CODS performances were then tested at 15 seconds and 2, 4, and 6 minutes post warm-up. Vertical jump and CODS significantly improved following all warm-up conditions (P < .05). Post warm-up vertical jump performance was not different between conditions (P = .430). Post warm-up CODS was significantly faster following the 5% (P = .02) and 10% (P < .001) loaded conditions compared with the control condition. In addition, peak CODS test performances, independent of recovery time, were faster than the control condition following the 10% loaded condition (P = .012). In conclusion, the current study demonstrates that a loaded warm-up augmented CODS, but not vertical jump performance, in elite badminton players.

Plugging the attention deficit: perceptual load counters increased distraction in ADHD.

PubMed

Forster, Sophie; Robertson, David J; Jennings, Alistair; Asherson, Philip; Lavie, Nilli

2014-01-01

Increased vulnerability to extraneous distraction is a key symptom of Attention-Deficit Hyperactivity Disorder (ADHD), which may have particularly disruptive consequences. Here we apply Load Theory of attention to increase understanding of this symptom, and to explore a potential method for ameliorating it. Previous research in nonclinical populations has highlighted increased perceptual load as a means of improving the ability to focus attention and avoid distraction. The present study examines whether adults with ADHD can also benefit from conditions of high perceptual load to improve their focused attention abilities. We tested adults with ADHD and age- and IQ-matched controls on a novel measure of irrelevant distraction under load, designed to parallel the form of distraction that is symptomatic of ADHD. During a letter search task, in which perceptual load was varied through search set size, participants were required to ignore salient yet entirely irrelevant distractors (colorful images of cartoon characters) presented infrequently (10% of trials). The presence of these distractors produced a significantly greater interference effect on the search RTs for the adults with ADHD compared with controls, p = .005, ηp² = .231. Perceptual load, however, significantly reduced distractor interference for the ADHD group and was as effective in reducing the elevated distractor interference in ADHD as it was for controls. These findings clarify the nature of the attention deficit underlying increased distraction in ADHD, and demonstrate a tangible method for overcoming it.

Experimental investigation of active loads control for aircraft landing gear

NASA Technical Reports Server (NTRS)

Mcgehee, J. R.; Dreher, R. C.

1982-01-01

Aircraft dynamic loads and vibrations resulting from landing impact and from runway and taxiway unevenness are recognized as significant in causing fatigue damage, dynamic stress on the airframe, crew and passenger discomfort, and reduction of the pilot's ability to control the aircraft during ground operations. One potential method for improving operational characteistics of aircraft on the ground is the application of active control technology to the landing gears to reduce ground loads applied to the airframe. An experimental investigation was conducted which simulated the landing dynamics of a light airplane to determine the feasibility and potential of a series hydraulic active control main landing gear. The experiments involved a passive gear and an active control gear. Results of this investigation show that a series hydraulically controlled gear is feasible and that such a gear is very effective in reducing the loads transmitted by the gear to the airframe during ground operations.

An Under-frequency Load Shedding Scheme with Continuous Load Control Proportional to Frequency Deviation

NASA Astrophysics Data System (ADS)

Li, Changgang; Sun, Yanli; Yu, Yawei

2017-05-01

Under frequency load shedding (UFLS) is an important measure to tackle with frequency drop caused by load-generation imbalance. In existing schemes, loads are shed by relays in a discontinuous way, which is the major reason leading to under-shedding and over-shedding problems. With the application of power electronics technology, some loads can be controlled continuously, and it is possible to improve the UFSL with continuous loads. This paper proposes an UFLS scheme by shedding loads continuously. The load shedding amount is proportional to frequency deviation before frequency reaches its minimum during transient process. The feasibility of the proposed scheme is analysed with analytical system frequency response model. The impacts of governor droop, system inertia, and frequency threshold on the performance of the proposed UFLS scheme are discussed. Cases are demonstrated to validate the proposed scheme by comparing it with conventional UFLS schemes.

A biomechanical model for actively controlled snow ski bindings.

PubMed

Hull, M L; Ramming, J E

1980-11-01

Active control of snow ski bindings is a new design concept which potentially offers improved protection from lower extremity injury. Implementation of this concept entails measuring physical variables and calculating loading and/or deformation in injury prone musculoskeletal components. The subject of this paper is definition of a biomechanical model for calculating tibia torsion based on measurements of torsion loading between the boot and ski. Previous control schemes have used leg displacement only to indicate tibia torsion. The contributions of both inertial and velocity-dependent torques to tibia loading are explored and it is shown that both these moments must be included in addition to displacement-dependent moments. A new analog controller design which includes inertia, damping, and stiffness terms in the tibia load calculation is also presented.

Dead Zone Oscillator Control for Communication-Free Synchronization of Paralleled, Three-Phase, Current-Controlled Inverters

DTIC Science & Technology

2016-05-11

the phases of the system load and ground, so to size the voltage divider appropriately Vsys is set equal to the maximum phase-to-ground voltage. The...civilian and military systems is increasing due to technological improvements in power conversion and changing requirements in system loads. The development...of high-power pulsed loads on naval platforms, such as the Laser Weapon System (LaWS) and the electromagnetic railgun, calls for the ability to

Effects of resistance training using known vs unknown loads on eccentric-phase adaptations and concentric velocity.

PubMed

Hernández-Davó, J L; Sabido, R; Behm, D G; Blazevich, A J

2018-02-01

The aims of this study were to compare both eccentric- and concentric-phase adaptations in highly trained handball players to 4 weeks of twice-weekly rebound bench press throw training with varying loads (30%, 50% and 70% of one-repetition maximum [1-RM]) using either known (KL) or unknown (UL) loads and to examine the relationship between changes in eccentric- and concentric-phase performance. Twenty-eight junior team handball players were divided into two experimental groups (KL or UL) and a control group. KL subjects were told the load prior each repetition, while UL were blinded. For each repetition, the load was dropped and then a rebound bench press at maximum velocity was immediately performed. Both concentric and eccentric velocity as well as eccentric kinetic energy and musculo-articular stiffness prior to the eccentric-concentric transition were measured. Results showed similar increases in both eccentric velocity and kinetic energy under the 30% 1-RM but greater improvements under 50% and 70% 1-RM loads for UL than KL. UL increased stiffness under all loads (with greater magnitude of changes). KL improved concentric velocity only under the 30% 1-RM load while UL also improved under 50% and 70% 1-RM loads. Improvements in concentric movement velocity were moderately explained by changes in eccentric velocity (R 2 =.23-.62). Thus, UL led to greater improvements in concentric velocity, and the improvement is potentially explained by increases in the speed (as well as stiffness and kinetic energy) of the eccentric phase. Unknown load training appears to have significant practical use for the improvement of multijoint stretch-shortening cycle movements. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A nonlinear control scheme based on dynamic evolution path theory for improved dynamic performance of boost PFC converter working on nonlinear features.

PubMed

Mohanty, Pratap Ranjan; Panda, Anup Kumar

2016-11-01

This paper is concerned to performance improvement of boost PFC converter under large random load fluctuation, ensuring unity power factor (UPF) at source end and regulated voltage at load side. To obtain such performance, a nonlinear controller based on dynamic evolution path theory is designed and its robustness is examined under both heavy and light loading condition. In this paper, %THD and zero-cross-over dead-zone of input current is significantly reduced. Also, very less response time of input current and output voltage to that of load and reference variation is remarked. A simulation model of proposed system is designed and it is realized using dSPACE 1104 signal processor for a 390V DC , 500W prototype. The relevant experimental and simulation waveforms are presented. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Laminar flow control perforated wing panel development

NASA Technical Reports Server (NTRS)

Fischler, J. E.

1986-01-01

Many structural concepts for a wing leading edge laminar flow control hybrid panel were analytically investigated. After many small, medium, and large tests, the selected design was verified. New analytic methods were developed to combine porous titanium sheet bonded to a substructure of fiberglass and carbon/epoxy cloth. At -65 and +160 F test conditions, the critical bond of the porous titanium to the composite failed at lower than anticipated test loads. New cure cycles, design improvements, and test improvements significantly improved the strength and reduced the deflections from thermal and lateral loadings. The wave tolerance limits for turbulence were not exceeded. Consideration of the beam column midbay deflections from the combinations of the axial and lateral loadings and thermal bowing at -65 F, room temperature, and +160 F were included. Many lap shear tests were performed at several cure cycles. Results indicate that sufficient verification was obtained to fabricate a demonstration vehicle.

Study of Flexible Load Dispatch to Improve the Capacity of Wind Power Absorption

NASA Astrophysics Data System (ADS)

Yunlei, Yang; Shifeng, Zhang; Xiao, Chang; Da, Lei; Min, Zhang; Jinhao, Wang; Shengwen, Li; Huipeng, Li

2017-05-01

The dispatch method which track the trend of load demand by arranging the generation scheme of controllable hydro or thermal units faces great difficulties and challenges. With the increase of renewable energy sources such as wind power and photovoltaic power introduced to grid, system has to arrange much more spinning reserve units to compensate the unbalanced power. How to exploit the peak-shaving potential of flexible load which can be shifted with time or storage energy has become many scholars’ research direction. However, the modelling of different kinds of load and control strategy is considerably difficult, this paper choose the Air Conditioner with compressor which can storage energy in fact to study. The equivalent thermal parameters of Air Conditioner has been established. And with the use of “loop control” strategies, we can predict the regulated power of Air Conditioner. Then we established the Gen-Load optimal scheduling model including flexible load based on traditional optimal scheduling model. At last, an improved IEEE-30 case is used to verify. The result of simulation shows that flexible load can fast-track renewable power changes. More than that, with flexible load and reasonable incentive method to consumers, the operating cost of the system can be greatly cut down.

Procedure for chromatography involving sample solvent with higher elution strength than the mobile phase.

PubMed

Patil, Nitin S; Mendhe, Rakesh B; Sankar, Ajeet A; Iyer, Harish

2008-01-11

In preparative chromatography, often the solubility of the sample in the mobile phase is limited, making the mobile phase unsuitable as a solvent for preparation of load. Generally, solvents that have high solubility for the sample also have higher elution strengths than the mobile phase. Additionally, at high loading volumes, these strong sample solvents are known to adversely affect the band profiles leading to poor chromatographic performance. Here, we show that controlling the mobile phase strength during loading and post-load elution resulted in improved band profiles when the sample solvent was stronger than the mobile phase. Such an approach improves performance in preparative chromatography by allowing either higher sample loading or higher organic content in mobile phase (without loss of yield). Alternately, the approach can be used for improvement in performance by increase in yield or product purity.

Using spatially detailed water-quality data and solute-transport modeling to improve support total maximum daily load development

USGS Publications Warehouse

Walton-Day, Katherine; Runkel, Robert L.; Kimball, Briant A.

2012-01-01

Spatially detailed mass-loading studies and solute-transport modeling using OTIS (One-dimensional Transport with Inflow and Storage) demonstrate how natural attenuation and loading from distinct and diffuse sources control stream water quality and affect load reductions predicted in total maximum daily loads (TMDLs). Mass-loading data collected during low-flow from Cement Creek (a low-pH, metal-rich stream because of natural and mining sources, and subject to TMDL requirements) were used to calibrate OTIS and showed spatially variable effects of natural attenuation (instream reactions) and loading from diffuse (groundwater) and distinct sources. OTIS simulations of the possible effects of TMDL-recommended remediation of mine sites showed less improvement to dissolved zinc load and concentration (14% decrease) than did the TMDL (53-63% decrease). The TMDL (1) assumed conservative transport, (2) accounted for loads removed by remediation by subtracting them from total load at the stream mouth, and (3) did not include diffuse-source loads. In OTIS, loads were reduced near their source; the resulting concentration was decreased by natural attenuation and increased by diffuse-source loads during downstream transport. Thus, by not including natural attenuation and loading from diffuse sources, the TMDL overestimated remediation effects at low flow. Use of the techniques presented herein could improve TMDLs by incorporating these processes during TMDL development.

The Role of Mechanical Loading in Tendon Development, Maintenance, Injury, and Repair

PubMed Central

Galloway, Marc T.; Lalley, Andrea L.; Shearn, Jason T.

2013-01-01

➤ Tendon injuries often result from excessive or insufficient mechanical loading, impairing the ability of the local tendon cell population to maintain normal tendon function. ➤ The resident cell population composing tendon tissue is mechanosensitive, given that the cells are able to alter the extracellular matrix in response to modifications of the local loading environment. ➤ Natural tendon healing is insufficient, characterized by improper collagen fibril diameter formation, collagen fibril distribution, and overall fibril misalignment. ➤ Current tendon repair rehabilitation protocols focus on implementing early, well-controlled eccentric loading exercises to improve repair outcome. ➤ Tissue engineers look toward incorporating mechanical loading regimens to precondition cell populations for the creation of improved biological augmentations for tendon repair. PMID:24005204

Adaptive Harmonic Detection Control of Grid Interfaced Solar Photovoltaic Energy System with Power Quality Improvement

NASA Astrophysics Data System (ADS)

Singh, B.; Goel, S.

2015-03-01

This paper presents a grid interfaced solar photovoltaic (SPV) energy system with a novel adaptive harmonic detection control for power quality improvement at ac mains under balanced as well as unbalanced and distorted supply conditions. The SPV energy system is capable of compensation of linear and nonlinear loads with the objectives of load balancing, harmonics elimination, power factor correction and terminal voltage regulation. The proposed control increases the utilization of PV infrastructure and brings down its effective cost due to its other benefits. The adaptive harmonic detection control algorithm is used to detect the fundamental active power component of load currents which are subsequently used for reference source currents estimation. An instantaneous symmetrical component theory is used to obtain instantaneous positive sequence point of common coupling (PCC) voltages which are used to derive inphase and quadrature phase voltage templates. The proposed grid interfaced PV energy system is modelled and simulated in MATLAB Simulink and its performance is verified under various operating conditions.

Sliding mode controller with modified sliding function for DC-DC Buck Converter.

PubMed

Naik, B B; Mehta, A J

2017-09-01

This article presents design of Sliding Mode Controller with proportional integral type sliding function for DC-DC Buck Converter for the controlled power supply. The converter with conventional sliding mode controller results in a steady state error in load voltage. The proposed modified sliding function improves the steady state and dynamic performance of the Convertor and facilitates better choices of controller tuning parameters. The conditions for existence of sliding modes for proposed control scheme are derived. The stability of the closed loop system with proposed sliding mode control is proved and improvement in steady state performance is exemplified. The idea of adaptive tuning for the proposed controller to compensate load variations is outlined. The comparative study of conventional and proposed control strategy is presented. The efficacy of the proposed strategy is endowed by the simulation and experimental results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Energy efficient transport technology: Program summary and bibliography

NASA Technical Reports Server (NTRS)

Middleton, D. B.; Bartlett, D. W.; Hood, R. V.

1985-01-01

The Energy Efficient Transport (EET) Program began in 1976 as an element of the NASA Aircraft Energy Efficiency (ACEE) Program. The EET Program and the results of various applications of advanced aerodynamics and active controls technology (ACT) as applicable to future subsonic transport aircraft are discussed. Advanced aerodynamics research areas included high aspect ratio supercritical wings, winglets, advanced high lift devices, natural laminar flow airfoils, hybrid laminar flow control, nacelle aerodynamic and inertial loads, propulsion/airframe integration (e.g., long duct nacelles) and wing and empennage surface coatings. In depth analytical/trade studies, numerous wind tunnel tests, and several flight tests were conducted. Improved computational methodology was also developed. The active control functions considered were maneuver load control, gust load alleviation, flutter mode control, angle of attack limiting, and pitch augmented stability. Current and advanced active control laws were synthesized and alternative control system architectures were developed and analyzed. Integrated application and fly by wire implementation of the active control functions were design requirements in one major subprogram. Additional EET research included interdisciplinary technology applications, integrated energy management, handling qualities investigations, reliability calculations, and economic evaluations related to fuel savings and cost of ownership of the selected improvements.

Real time PI-backstepping induction machine drive with efficiency optimization.

PubMed

Farhani, Fethi; Ben Regaya, Chiheb; Zaafouri, Abderrahmen; Chaari, Abdelkader

2017-09-01

This paper describes a robust and efficient speed control of a three phase induction machine (IM) subjected to load disturbances. First, a Multiple-Input Multiple-Output (MIMO) PI-Backstepping controller is proposed for a robust and highly accurate tracking of the mechanical speed and rotor flux. Asymptotic stability of the control scheme is proven by Lyapunov Stability Theory. Second, an active online optimization algorithm is used to optimize the efficiency of the drive system. The efficiency improvement approach consists of adjusting the rotor flux with respect to the load torque in order to minimize total losses in the IM. A dSPACE DS1104 R&D board is used to implement the proposed solution. The experimental results released on 3kW squirrel cage IM, show that the reference speed as well as the rotor flux are rapidly achieved with a fast transient response and without overshoot. A good load disturbances rejection response and IM parameters variation are fairly handled. The improvement of drive system efficiency reaches up to 180% at light load. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Distributed Aerodynamic Sensing and Processing Toolbox

NASA Technical Reports Server (NTRS)

Brenner, Martin; Jutte, Christine; Mangalam, Arun

2011-01-01

A Distributed Aerodynamic Sensing and Processing (DASP) toolbox was designed and fabricated for flight test applications with an Aerostructures Test Wing (ATW) mounted under the fuselage of an F-15B on the Flight Test Fixture (FTF). DASP monitors and processes the aerodynamics with the structural dynamics using nonintrusive, surface-mounted, hot-film sensing. This aerodynamic measurement tool benefits programs devoted to static/dynamic load alleviation, body freedom flutter suppression, buffet control, improvement of aerodynamic efficiency through cruise control, supersonic wave drag reduction through shock control, etc. This DASP toolbox measures local and global unsteady aerodynamic load distribution with distributed sensing. It determines correlation between aerodynamic observables (aero forces) and structural dynamics, and allows control authority increase through aeroelastic shaping and active flow control. It offers improvements in flutter suppression and, in particular, body freedom flutter suppression, as well as aerodynamic performance of wings for increased range/endurance of manned/ unmanned flight vehicles. Other improvements include inlet performance with closed-loop active flow control, and development and validation of advanced analytical and computational tools for unsteady aerodynamics.

Design and analysis of tilt integral derivative controller with filter for load frequency control of multi-area interconnected power systems.

PubMed

Kumar Sahu, Rabindra; Panda, Sidhartha; Biswal, Ashutosh; Chandra Sekhar, G T

2016-03-01

In this paper, a novel Tilt Integral Derivative controller with Filter (TIDF) is proposed for Load Frequency Control (LFC) of multi-area power systems. Initially, a two-area power system is considered and the parameters of the TIDF controller are optimized using Differential Evolution (DE) algorithm employing an Integral of Time multiplied Absolute Error (ITAE) criterion. The superiority of the proposed approach is demonstrated by comparing the results with some recently published heuristic approaches such as Firefly Algorithm (FA), Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) optimized PID controllers for the same interconnected power system. Investigations reveal that proposed TIDF controllers provide better dynamic response compared to PID controller in terms of minimum undershoots and settling times of frequency as well as tie-line power deviations following a disturbance. The proposed approach is also extended to two widely used three area test systems considering nonlinearities such as Generation Rate Constraint (GRC) and Governor Dead Band (GDB). To improve the performance of the system, a Thyristor Controlled Series Compensator (TCSC) is also considered and the performance of TIDF controller in presence of TCSC is investigated. It is observed that system performance improves with the inclusion of TCSC. Finally, sensitivity analysis is carried out to test the robustness of the proposed controller by varying the system parameters, operating condition and load pattern. It is observed that the proposed controllers are robust and perform satisfactorily with variations in operating condition, system parameters and load pattern. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Lidar-Enhanced Wind Turbine Control: Past, Present, and Future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scholbrock, Andrew; Fleming, Paul; Schlipf, David

The main challenges in harvesting energy from the wind arise from the unknown incoming turbulent wind field. Balancing the competing interests of reduction in structural loads and increasing energy production is the goal of a wind turbine controller to reduce the cost of producing wind energy. Conventional wind turbines use feedback methods to optimize these goals, reacting to wind disturbances after they have already impacted the wind turbine. Lidar sensors offer a means to provide additional inputs to a wind turbine controller, enabling new techniques to improve control methods, allowing a controller to actuate a wind turbine in anticipation ofmore » an incoming wind disturbance. This paper will look at the development of lidar-enhanced controls and how they have been used for various turbine load reductions with pitch actuation, as well as increased energy production with improved yaw control. Ongoing work will also be discussed to show that combining pitch and torque control using feedforward nonlinear model predictive control can lead to both reduced loads and increased energy production. Future work is also proposed on extending individual wind turbine controls to the wind plant level and determining how lidars can be used for control methods to further lower the cost of wind energy by minimizing wake impacts in a wind farm.« less

Plugging the Attention Deficit: Perceptual Load Counters Increased Distraction in ADHD

PubMed Central

2013-01-01

Objective: Increased vulnerability to extraneous distraction is a key symptom of Attention-Deficit Hyperactivity Disorder (ADHD), which may have particularly disruptive consequences. Here we apply Load Theory of attention to increase understanding of this symptom, and to explore a potential method for ameliorating it. Previous research in nonclinical populations has highlighted increased perceptual load as a means of improving the ability to focus attention and avoid distraction. The present study examines whether adults with ADHD can also benefit from conditions of high perceptual load to improve their focused attention abilities. Method: We tested adults with ADHD and age- and IQ-matched controls on a novel measure of irrelevant distraction under load, designed to parallel the form of distraction that is symptomatic of ADHD. During a letter search task, in which perceptual load was varied through search set size, participants were required to ignore salient yet entirely irrelevant distractors (colorful images of cartoon characters) presented infrequently (10% of trials). Results: The presence of these distractors produced a significantly greater interference effect on the search RTs for the adults with ADHD compared with controls, p = .005, ηp2 = .231. Perceptual load, however, significantly reduced distractor interference for the ADHD group and was as effective in reducing the elevated distractor interference in ADHD as it was for controls. Conclusions: These findings clarify the nature of the attention deficit underlying increased distraction in ADHD, and demonstrate a tangible method for overcoming it. PMID:24219607

Coordinated Optimization of Distributed Energy Resources and Smart Loads in Distribution Systems: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Rui; Zhang, Yingchen

2016-08-01

Distributed energy resources (DERs) and smart loads have the potential to provide flexibility to the distribution system operation. A coordinated optimization approach is proposed in this paper to actively manage DERs and smart loads in distribution systems to achieve the optimal operation status. A three-phase unbalanced Optimal Power Flow (OPF) problem is developed to determine the output from DERs and smart loads with respect to the system operator's control objective. This paper focuses on coordinating PV systems and smart loads to improve the overall voltage profile in distribution systems. Simulations have been carried out in a 12-bus distribution feeder andmore » results illustrate the superior control performance of the proposed approach.« less

Coordinated Optimization of Distributed Energy Resources and Smart Loads in Distribution Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Rui; Zhang, Yingchen

2016-11-14

Distributed energy resources (DERs) and smart loads have the potential to provide flexibility to the distribution system operation. A coordinated optimization approach is proposed in this paper to actively manage DERs and smart loads in distribution systems to achieve the optimal operation status. A three-phase unbalanced Optimal Power Flow (OPF) problem is developed to determine the output from DERs and smart loads with respect to the system operator's control objective. This paper focuses on coordinating PV systems and smart loads to improve the overall voltage profile in distribution systems. Simulations have been carried out in a 12-bus distribution feeder andmore » results illustrate the superior control performance of the proposed approach.« less

Evaluation Of Rotation Frequency Gas-Diesel Engines When Using Automatic Control System

NASA Astrophysics Data System (ADS)

Zhilenkov, A.; Efremov, A.

2017-01-01

A possibility of quality improvement of stabilization of rotation frequency of the gas-diesels used as prime mover of generator set in the multigenerator units working for abruptly variable load of large power is considered. An evaluation is made on condition of fuzzy controller use developed and described by the authors in a number of articles. An evaluation has shown that theoretically, the revolution range of gas-diesel engine may be reduced at 25-30 times at optimal settings of the controller in all the power range. The results of modeling showing a considerable quality improvement of transient processes in the investigated system at a sharp change of loading are presented in this article.

FUZZY-LOGIC-BASED CONTROLLERS FOR EFFICIENCY OPTIMIZATION OF INVERTER-FED INDUCTION MOTOR DRIVES

EPA Science Inventory

This paper describes a fuzzy-logic-based energy optimizing controller to improve the efficiency of induction motor/drives operating at various load (torque) and speed conditions. Improvement of induction motor efficiency is important not only from the considerations of energy sav...

Effect of Dietary Iron Loading on Recognition Memory in Growing Rats

PubMed Central

Han, Murui; Kim, Jonghan

2015-01-01

While nutritional and neurobehavioral problems are associated with both iron deficiency during growth and overload in the elderly, the effect of iron loading in growing ages on neurobehavioral performance has not been fully explored. To characterize the role of dietary iron loading in memory function in the young, weanling rats were fed iron-loading diet (10,000 mg iron/kg diet) or iron-adequate control diet (50 mg/kg) for one month, during which a battery of behavioral tests were conducted. Iron-loaded rats displayed elevated non-heme iron levels in serum and liver, indicating a condition of systemic iron overload. In the brain, non-heme iron was elevated in the prefrontal cortex of iron-loaded rats compared with controls, whereas there was no difference in iron content in other brain regions between the two diet groups. While iron loading did not alter motor coordination or anxiety-like behavior, iron-loaded rats exhibited a better recognition memory, as represented by an increased novel object recognition index (22% increase from the reference value) than control rats (12% increase; P=0.047). Western blot analysis showed an up-regulation of dopamine receptor 1 in the prefrontal cortex from iron-loaded rats (142% increase; P=0.002). Furthermore, levels of glutamate receptors (both NMDA and AMPA) and nicotinic acetylcholine receptor (nAChR) were significantly elevated in the prefrontal cortex of iron-loaded rats (62% increase in NR1; 70% increase in Glu1A; 115% increase in nAChR). Dietary iron loading also increased the expression of NMDA receptors and nAChR in the hippocampus. These results support the idea that iron is essential for learning and memory and further reveal that iron supplementation during developmental and rapidly growing periods of life improves memory performance. Our investigation also demonstrates that both cholinergic and glutamatergic neurotransmission pathways are regulated by dietary iron and provides a molecular basis for the role of iron loading in improved memory. PMID:25746420

Ensemble-based uncertainty quantification for coordination and control of thermostatically controlled loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Weixuan; Lian, Jianming; Engel, Dave

2017-07-27

This paper presents a general uncertainty quantification (UQ) framework that provides a systematic analysis of the uncertainty involved in the modeling of a control system, and helps to improve the performance of a control strategy.

Physical load handling and listening comprehension effects on balance control.

PubMed

Qu, Xingda

2010-12-01

The purpose of this study was to determine the physical load handling and listening comprehension effects on balance control. A total of 16 young and 16 elderly participants were recruited in this study. The physical load handling task required holding a 5-kg load in each hand with arms at sides. The listening comprehension task involved attentive listening to a short conversation. Three short questions were asked regarding the conversation right after the testing trial to test the participants' attentiveness during the experiment. Balance control was assessed by centre of pressure-based measures, which were calculated from the force platform data when the participants were quietly standing upright on a force platform. Results from this study showed that both physical load handling and listening comprehension adversely affected balance control. Physical load handling had a more deleterious effect on balance control under the listening comprehension condition vs. no-listening comprehension condition. Based on the findings from this study, interventions for the improvement of balance could be focused on avoiding exposures to physically demanding tasks and cognitively demanding tasks simultaneously. STATEMENT OF RELEVANCE: Findings from this study can aid in better understanding how humans maintain balance, especially when physical and cognitive loads are applied. Such information is useful for developing interventions to prevent fall incidents and injuries in occupational settings and daily activities.

Novel Augmentation Technique for Patellar Tendon Repair Improves Strength and Decreases Gap Formation: A Cadaveric Study.

PubMed

Black, James C; Ricci, William M; Gardner, Michael J; McAndrew, Christopher M; Agarwalla, Avinesh; Wojahn, Robert D; Abar, Orchid; Tang, Simon Y

2016-12-01

Patellar tendon ruptures commonly are repaired using transosseous patellar drill tunnels with modified-Krackow sutures in the patellar tendon. This simple suture technique has been associated with failure rates and poor clinical outcomes in a modest proportion of patients. Failure of this repair technique can result from gap formation during loading or a single catastrophic event. Several augmentation techniques have been described to improve the integrity of the repair, but standardized biomechanical evaluation of repair strength among different techniques is lacking. The purpose of this study was to describe a novel figure-of-eight suture technique to augment traditional fixation and evaluate its biomechanical performance. We hypothesized that the augmentation technique would (1) reduce gap formation during cyclic loading and (2) increase the maximum load to failure. Ten pairs (two male, eight female) of fresh-frozen cadaveric knees free of overt disorders or patellar tendon damage were used (average donor age, 76 years; range, 65-87 years). For each pair, one specimen underwent the standard transosseous tunnel suture repair with a modified-Krackow suture technique and the second underwent the standard repair with our experimental augmentation method. Nine pairs were suitable for testing. Each specimen underwent cyclic loading while continuously measuring gap formation across the repair. At the completion of cyclic loading, load to failure testing was performed. A difference in gap formation and mean load to failure was seen in favor of the augmentation technique. At 250 cycles, a 68% increase in gap formation was seen for the control group (control: 5.96 ± 0.86 mm [95% CI, 5.30-6.62 mm]; augmentation: 3.55 ± 0.56 mm [95% CI, 3.12-3.98 mm]; p = 0.02). The mean load to failure was 13% greater in the augmentation group (control: 899.57 ± 96.94 N [95% CI, 825.06-974.09 N]; augmentation: 1030.70 ± 122.41 N [95% CI, 936.61-1124.79 N]; p = 0.01). This biomechanical study showed improved performance of a novel augmentation technique compared with the standard repair, in terms of reduced gap formation during cyclic loading and increased maximum load to failure. Decreased gap formation and higher load to failure may improve healing potential and minimize failure risk. This study shows a potential biomechanical advantage of the augmentation technique, providing support for future clinical investigations comparing this technique with other repair methods that are in common use such as transosseous suture repair.

Flight directors for STOl aircraft

NASA Technical Reports Server (NTRS)

Rabin, U. H.

1983-01-01

Flight director logic for flight path and airspeed control of a powered-lift STOL aircraft in the approach, transition, and landing configurations are developed. The methods for flight director design are investigated. The first method is based on the Optimal Control Model (OCM) of the pilot. The second method, proposed here, uses a fixed dynamic model of the pilot in a state space formulation similar to that of the OCM, and includes a pilot work-load metric. Several design examples are presented with various aircraft, sensor, and control configurations. These examples show the strong impact of throttle effectiveness on the performance and pilot work-load associated with manual control of powered-lift aircraft during approach. Improved performed and reduced pilot work-load can be achieved by using direct-lift-control to increase throttle effectiveness.

Compound Velocity Synchronizing Control Strategy for Electro-Hydraulic Load Simulator and Its Engineering Application.

PubMed

Han, Songshan; Jiao, Zongxia; Yao, Jianyong; Shang, Yaoxing

2014-09-01

An electro-hydraulic load simulator (EHLS) is a typical case of torque systems with strong external disturbances from hydraulic motion systems. A new velocity synchronizing compensation strategy is proposed in this paper to eliminate motion disturbances, based on theoretical and experimental analysis of a structure invariance method and traditional velocity synchronizing compensation controller (TVSM). This strategy only uses the servo-valve's control signal of motion system and torque feedback of torque system, which could avoid the requirement on the velocity and acceleration signal in the structure invariance method, and effectively achieve a more accurate velocity synchronizing compensation in large loading conditions than a TVSM. In order to facilitate the implementation of this strategy in engineering cases, the selection rules for compensation parameters are proposed. It does not rely on any accurate information of structure parameters. This paper presents the comparison data of an EHLS with various typical operating conditions using three controllers, i.e., closed loop proportional integral derivative (PID) controller, TVSM, and the proposed improved velocity synchronizing controller. Experiments are conducted to confirm that the new strategy performs well against motion disturbances. It is more effective to improve the tracking accuracy and is a more appropriate choice for engineering applications.

Reducing cognitive load while teaching complex instruction to occupational therapy students.

PubMed

Pociask, Fredrick D; DiZazzo-Miller, Rosanne; Samuel, Preethy S

2013-01-01

Cognitive load theory is a field of research used to improve the learning of complex cognitive tasks by matching instruction to the learner's cognitive architecture. We used an experimental posttest control-group design to test the effectiveness of instruction designed to reduce cognitive load (CL) and improve instructional effectiveness in teaching complex instruction to 24 first-year master's students under authentic classroom conditions. We modified historically taught instruction using an isolated-to-interacting-elements sequencing approach intended to reduce high CL levels. We compared control and modified instructional formats using written assessment scores, subjective ratings of CL, and task completion times. Analysis of variance revealed significant differences for postinstruction, posttest CL ratings, and delayed written posttest scores (p < .05). No significant differences were identified for posttest completion times. Findings suggest that this approach can be used to improve instructional efficiency in teaching human locomotion to occupational therapy students. Copyright © 2013 by the American Occupational Therapy Association, Inc.

Effects of hydrogenated TiO2 nanotube arrays on protein adsorption and compatibility with osteoblast-like cells.

PubMed

Lu, Ran; Wang, Caiyun; Wang, Xin; Wang, Yuji; Wang, Na; Chou, Joshua; Li, Tao; Zhang, Zhenting; Ling, Yunhan; Chen, Su

2018-01-01

Modified titanium (Ti) substrates with titanium dioxide (TiO 2 ) nanotubes have broad usage as implant surface treatments and as drug delivery systems. To improve drug-loading capacity and accelerate bone integration with titanium, in this study, we hydrogenated anodized titanium dioxide nanotubes (TNTs) by a thermal treatment. Three groups were examined, namely: hydrogenated TNTs (H 2 -TNTs, test), unmodified TNTs (air-TNTs, control), and Ti substrates (Ti, control). Our results showed that oxygen vacancies were present in all the nanotubes. The quantity of -OH groups greatly increased after hydrogenation. Furthermore, the protein adsorption and loading capacity of the H 2 -TNTs were considerably enhanced as compared with the properties of the air-TNTs ( P <0.05). Additionally, time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to investigate the interactions of TNTs with proteins. During the protein-loading process, the H 2 -TNTs not only enabled rapid protein adsorption, but also decreased the rate of protein elution compared with that of the air-TNTs. We found that the H 2 -TNTs exhibited better biocompatibility than the air-TNT and Ti groups. Both cell adhesion activity and alkaline phosphatase activity were significantly improved toward MG-63 human osteoblast-like cells as compared with the control groups ( P <0.05). We conclude that hydrogenated TNTs could greatly improve the loading capacity of bioactive molecules and MG-63 cell proliferation.

Design and Control of a Micro/Nano Load Stage for In-Situ AFM Observation and Nanoscale Structural and Mechanical Characterization of MWCNT-Epoxy Composites

NASA Astrophysics Data System (ADS)

Leininger, Wyatt Christopher

Nanomaterial composites hold improvement potential for many materials. Improvements arise through known material behaviors and unique nanoscale effects to improve performance in areas including elastic modulus and damping as well as various processes, and products. Review of research spurred development of a load-stage. The load stage could be used independently, or in conjunction with an AFM to investigate bulk and nanoscale material mechanics. The effect of MWCNT content on structural damping, elastic modulus, toughness, loss modulus, and glass transition temperature was investigated using the load stage, AMF, and DMA. Initial investigation showed elastic modulus increased 23% with 1wt.% MWCNT versus pure epoxy and in-situ imaging observed micro/nanoscale deformation. Dynamic capabilities of the load stage were investigated as a method to achieve higher stress than available through DMA. The system showed energy dissipation across all reinforce levels, with 480% peak for the 1wt.% MWCNT material vs. the neat epoxy at 1Hz.

An Energy Saving Green Plug Device for Nonlinear Loads

NASA Astrophysics Data System (ADS)

Bloul, Albe; Sharaf, Adel; El-Hawary, Mohamed

2018-03-01

The paper presents a low cost a FACTS Based flexible fuzzy logic based modulated/switched tuned arm filter and Green Plug compensation (SFC-GP) scheme for single-phase nonlinear loads ensuring both voltage stabilization and efficient energy utilization. The new Green Plug-Switched filter compensator SFC modulated LC-Filter PWM Switched Capacitive Compensation Devices is controlled using a fuzzy logic regulator to enhance power quality, improve power factor at the source and reduce switching transients and inrush current conditions as well harmonic contents in source current. The FACTS based SFC-GP Device is a member of family of Green Plug/Filters/Compensation Schemes used for efficient energy utilization, power quality enhancement and voltage/inrush current/soft starting control using a dynamic error driven fuzzy logic controller (FLC). The device with fuzzy logic controller is validated using the Matlab / Simulink Software Environment for enhanced power quality (PQ), improved power factor and reduced inrush currents. This is achieved using modulated PWM Switching of the Filter-Capacitive compensation scheme to cope with dynamic type nonlinear and inrush cyclical loads..

Controlled release in transdermal pressure sensitive adhesives using organosilicate nanocomposites.

PubMed

Shaikh, Sohel; Birdi, Anil; Qutubuddin, Syed; Lakatosh, Eric; Baskaran, Harihara

2007-12-01

Polydimethyl siloxane (PDMS) based pressure sensitive adhesives (PSA) incorporating organo-clays at different loadings were fabricated via solution casting. Partially exfoliated nanocomposites were obtained for the hydroxyl terminated PDMS in ethyl acetate solvent as determined by X-ray diffraction and atomic force microscopy. Drug release studies showed that the initial burst release was substantially reduced and the drug release could be controlled by the addition of organo-clay. Shear strength and shear adhesion failure temperature (SAFT) measurements indicated substantial improvement in adhesive properties of the PSA nanocomposite adhesives. Shear strength showed more than 200% improvement at the lower clay loadings and the SAFT increased by about 21% due to the reinforcement provided by the nano-dispersed clay platelets. It was found that by optimizing the level of the organosilicate additive to the polymer matrix, superior control over drug release kinetics and simultaneous improvements in adhesive properties could be attained for a transdermal PSA formulation.

Vehicle anti-rollover control strategy based on load transferring rate

NASA Astrophysics Data System (ADS)

Dai, W. T.; Du, H. Q.; Zhang, L.

2018-03-01

When vehicles is drived on a low adhesion road or going on a high speed and sharp turn, it is prone to product some lateral stability problems, such as lateral sideslip or rollover. In order to improve the vehicle anti-rollover stability under these limited conditions, a SUV vehicle model with high mass center was built based on the software of CarSim and the rollover stability controller was designed using the static threshold value method for the lateral load transferring rate (LTR). The simulations are shown that the vehicle anti-rollover stability under limit conditions is improved using the SUV model.

+Gz load and executive functions.

PubMed

Biernacki, Marcin P; Tarnowski, Adam; Lengsfeld, Kamila; Lewkowicz, Rafał; Kowalczuk, Krzysztof; Dereń, Miroslaw

2013-05-01

Pilots are constantly exposed to a number of environmental factors, which include +Gz load. Physiological changes evoked by +Gz stimuli have already been well investigated in aviation medicine. However, the influence of +Gz stimulation on executive functions in pilots has not yet been thoroughly explored. There were 20 pilot cadets between the ages of 19 and 22 yr who volunteered to participate in the experiment. The subjects were divided into two groups: the G-load group, which was exposed to accelerations in the centrifuge, and the control group, which did not undergo this stimulation. Executive functions were assessed by means of the Schulte tables and the Rey-Osterrieth complex figure test. +Gz load exposure significantly improved attention switching. This relationship was valid for performance speed (M = 268.09 s in the pretest in the G-load group; M = 228.09 s in the posttest in the G-load group) and for the cumulative time of mistakes (M = 26.73 s in the pretest in the G-load group; M = 12 s in the posttest in the G-load group), whereas reproduction of visuospatial stimuli from memory deteriorated significantly under the influence of +Gz stimulation (M = 17.18 points in the posttest in the G-load group; M = 28.18 points in the posttest in the control group). These results suggest that the impact of +Gz load is not homogenous and unidirectional, since it improves attention switching but visuospatial working memory decreases under its influence. These aspects are particularly important for understanding the mechanisms responsible for maintaining situational awareness during the flight.

Technology Solutions Case Study: Advanced Boiler Load Monitoring Controls, Chicago, Illinois

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2014-09-01

Most of Chicago’s older multifamily housing stock is heated by centrally metered steam or hydronic systems. The cost of heat is typically absorbed into the owner’s operating cost and is then passed to tenants. Central boilers typically have long service lifetimes; the incentive for retrofit system efficiency upgrades is greater than equipment replacement for the efficiency-minded owner. System improvements as the “low-hanging fruit” are familiar, from improved pipe insulation to aftermarket controls such as outdoor temperature reset (OTR) or lead/lag controllers for sites with multiple boilers. Beyond these initial system efficiency upgrades are an emerging class of Advanced Load Monitoringmore » (ALM) aftermarket controllers that dynamically respond to the boiler load, with claims of 10% to 30% of fuel savings over a heating season. In this project, the Building America team Partnership for Advanced Residential Retrofit (PARR) installed and monitored an ALM aftermarket controller, the M2G from Greffen Systems, at two Chicago area multifamily buildings with existing OTR control. Results show that energy savings depend on the degree to which boilers are oversized for their load, represented by cycling rates. Also, savings vary over the heating season with cycling rates, with greater savings observed in shoulder months. Over the monitoring period, oversized boilers at one site showed reductions in cycling and energy consumption in line with prior laboratory studies, while less oversized boilers at another site showed muted savings.« less

Oral hesperidin-Amorphization and improved dissolution properties by controlled loading onto porous silica.

PubMed

Wei, Qionghua; Keck, Cornelia M; Müller, Rainer H

2017-02-25

The oral bioavailability of poorly soluble drugs can be improved by amorphization generated by loading into the pores of mesoporous particles (pore size 2-50nm). The main mechanisms are increased kinetic saturation solubility and dissolution velocity due to the amorphous drug state and the nano-size of the drug (=increased dissolution pressure). In this study, the maximum achievable drug loading compared to the theoretical drug loading, and the effect of drug loading degree on the dissolution properties (solubility, dissolution velocity) were investigated. Hesperidin was used as the model active (having also practical relevance for e.g. nutraceutical products), loading was performed onto AEROPERL ® 300 Pharma. Degree of successful drug loading could be easily followed by simple light microscopy (=useful tool for formulation optimization), and was in agreement with scanning electron microscopy. Amorphous versus crystalline state was followed by X-ray diffraction and differential scanning calorimetry. Loadings prepared were 28.6wt.%, 54.5wt.% and 60.0wt.%, the maximum theoretical loading was 72.5wt.%. Obviously the maximum drug loading is not achievable, the 54.5wt.% drug loading was the practical maximum with already some minor crystalline hesperidin on the surface. Interestingly, the maximum kinetic saturation solubility was obtained for the 54.5wt.% drug loading (941.74μg/ml in pH 6.8 PBS), versus 408.80μg/ml for the 60.0wt.% drug loading (=overloaded system). The raw drug powder had a thermodynamic solubility of only 18.40μg/ml. The fastest in vitro release was obtained with the 28.6wt.% loaded system, followed by the 54.5wt.% and 60.0wt.% loadings. The dissolution properties (solubility, dissolution velocity) can obviously be influenced by a "controlled loading". This is a simple, cost-effective technological alternative to modulating this property by chemical modification of silica, requiring a new costly regulatory approval of these chemically modified materials. Copyright © 2016. Published by Elsevier B.V.

Dual-arm manipulators with adaptive control

NASA Technical Reports Server (NTRS)

Seraji, Homayoun (Inventor)

1991-01-01

The described and improved multi-arm invention of this application presents three strategies for adaptive control of cooperative multi-arm robots which coordinate control over a common load. In the position-position control strategy, the adaptive controllers ensure that the end-effector positions of both arms track desired trajectories in Cartesian space despite unknown time-varying interaction forces exerted through a load. In the position-hybrid control strategy, the adaptive controller of one arm controls end-effector motions in the free directions and applied forces in the constraint directions; while the adaptive controller of the other arm ensures that the end-effector tracks desired position trajectories. In the hybrid-hybrid control strategy, the adaptive controllers ensure that both end-effectors track reference position trajectories while simultaneously applying desired forces on the load. In all three control strategies, the cross-coupling effects between the arms are treated as disturbances which are compensated for by the adaptive controllers while following desired commands in a common frame of reference. The adaptive controllers do not require the complex mathematical model of the arm dynamics or any knowledge of the arm dynamic parameters or the load parameters such as mass and stiffness. Circuits in the adaptive feedback and feedforward controllers are varied by novel adaptation laws.

Method and apparatus for adaptive force and position control of manipulators

NASA Technical Reports Server (NTRS)

Seraji, Homayoun (Inventor)

1995-01-01

The described and improved multi-arm invention of this application presents three strategies for adaptive control of cooperative multi-arm robots which coordinate control over a common load. In the position-position control strategy, the adaptive controllers ensure that the end-effector positions of both arms track desired trajectories in Cartesian space despite unknown time-varying interaction forces exerted through a load. In the position-hybrid control strategy, the adaptive controller of one arm controls end-effector motions in the free directions and applied forces in the constraint directions; while the adaptive controller of the other arm ensures that the end-effector tracks desired position trajectories. In the hybrid-hybrid control strategy, the adaptive controllers ensure that both end-effectors track reference position trajectories while simultaneously applying desired forces on the load. In all three control strategies, the cross-coupling effects between the arms are treated as disturbances which are compensated for by the adaptive controllers while following desired commands in a common frame of reference. The adaptive controllers do not require the complex mathematical model of the arm dynamics or any knowledge of the arm dynamic parameters or the load parameters such as mass and stiffness. Circuits in the adaptive feedback and feedforward controllers are varied by novel adaptation laws.

Coordinative Voltage Control Strategy with Multiple Resources for Distribution Systems of High PV Penetration: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Xiangqi; Zhang, Yingchen

This paper presents an optimal voltage control methodology with coordination among different voltage-regulating resources, including controllable loads, distributed energy resources such as energy storage and photovoltaics (PV), and utility voltage-regulating devices such as voltage regulators and capacitors. The proposed methodology could effectively tackle the overvoltage and voltage regulation device distortion problems brought by high penetrations of PV to improve grid operation reliability. A voltage-load sensitivity matrix and voltage-regulator sensitivity matrix are used to deploy the resources along the feeder to achieve the control objectives. Mixed-integer nonlinear programming is used to solve the formulated optimization control problem. The methodology has beenmore » tested on the IEEE 123-feeder test system, and the results demonstrate that the proposed approach could actively tackle the voltage problem brought about by high penetrations of PV and improve the reliability of distribution system operation.« less

Simulation Comparison of Wake Mitigation Control Strategies for a Two-Turbine Case

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Paul; Gebraad, Pieter M. O.; Lee, Sang

2015-12-01

Wind turbines arranged in a wind plant impact each other through their wakes. Wind plant control is an active research field that attempts to improve wind plant performance by coordinating control of individual turbines to take into account these turbine–wake interactions. High-fidelity simulations of a two-turbine fully waked scenario are used to investigate several wake mitigation strategies, in this paper, including modification of yaw and tilt angles of an upstream turbine to induce wake skew, as well as repositioning of the downstream turbine. The simulation results are compared through change relative to a baseline operation in terms of overall powermore » capture and loading on the upstream and downstream turbine. Results demonstrated improved power production for all methods. Moreover, analysis of control options, including individual pitch control, shows potential to minimize the increase of, or even reduce, turbine loads.« less

Smart Inverter Control and Operation for Distributed Energy Resources

NASA Astrophysics Data System (ADS)

Tazay, Ahmad F.

The motivation of this research is to carry out the control and operation of smart inverters and voltage source converters (VSC) for distributed energy resources (DERs) such as photovoltaic (PV), battery, and plug-in hybrid electric vehicles (PHEV). The main contribution of the research includes solving a couple of issues for smart grids by controlling and implementing multifunctions of VSC and smart inverter as well as improving the operational scheme of the microgrid. The work is mainly focused on controlling and operating of smart inverter since it promises a new technology for the future microgrid. Two major applications of the smart inverter will be investigated in this work based on the connection modes: microgrid at grid-tied mode and autonomous mode. In grid-tied connection, the smart inverter and VSC are used to integrate DER such as Photovoltaic (PV) and battery to provide suitable power to the system by controlling the supplied real and reactive power. The role of a smart inverter at autonomous mode includes supplying a sufficient voltage and frequency, mitigate abnormal condition of the load as well as equally sharing the total load's power. However, the operational control of the microgrid still has a major issue on the operation of the microgrid. The dissertation is divided into two main sections which are: 1. Low-level control of a single smart Inverter. 2. High-level control of the microgrid. The first part investigates a comprehensive research for a smart inverter and VSC technology at the two major connections of the microgrid. This involves controlling and modeling single smart inverter and VSC to solve specific issues of microgrid as well as improve the operation of the system. The research provides developed features for smart inverter comparing with a conventional voltage sourced converter (VSC). The two main connections for a microgrid have been deeply investigated to analyze a better way to develop and improve the operational procedure of the microgrid as well as solve specific issues of connecting the microgrid to the system. A detailed procedure for controlling VSC and designing an optimal operation of the controller is also covered in the first part of the dissertation. This section provides an optimal operation for controlling motor drive and demonstrates issues when motor load exists at an autonomous microgrid. It also provides a solution for specific issues at operating a microgrid at autonomous mode as well as improving the structural design for the grid-tied microgrid. The solution for autonomous microgrid includes changing the operational state of the switching pattern of the smart inverter to solve the issue of a common mode voltage (CMV) that appears across the motor load. It also solves the issue of power supplying to large loads, such as induction motors. The last section of the low-level section involves an improvement of the performance and operation of the PV charging station for a plug-in hybrid electric vehicle (PHEV) at grid-tied mode. This section provides a novel structure and smart controller for PV charging station using three-phase hybrid boost converter topology. It also provides a form of applications of a multifunction smart inverter using PV charging station. The second part of the research is focusing on improving the performance of the microgrid by integrating several smart inverters to form a microgrid. It investigates the issue of connecting DER units with the microgrid at real applications. One of the common issues of the microgrid is the circulating current which is caused by poor reactive power sharing accuracy. When more than two DER units are connected in parallel, a microgrid is forming be generating required power for the load. When the microgrid is operated at autonomous mode, all DER units participate in generating voltage and frequency as well as share the load's power. This section provides a smart and novel controlling technique to solve the issue of unequal power sharing. The feature of the smart inverter is realized by the communication link between smart inverters and the main operator. The analysis and derivation of the problem are presented in this section. The dissertation has led to two accepted conference papers, one accepted transaction IEEE manuscript, and one submitted IET transaction manuscript. The future work aims to improve the current work by investigating the performance of the smart inverter at real applications.

Intelligent voltage control strategy for three-phase UPS inverters with output LC filter

NASA Astrophysics Data System (ADS)

Jung, J. W.; Leu, V. Q.; Dang, D. Q.; Do, T. D.; Mwasilu, F.; Choi, H. H.

2015-08-01

This paper presents a supervisory fuzzy neural network control (SFNNC) method for a three-phase inverter of uninterruptible power supplies (UPSs). The proposed voltage controller is comprised of a fuzzy neural network control (FNNC) term and a supervisory control term. The FNNC term is deliberately employed to estimate the uncertain terms, and the supervisory control term is designed based on the sliding mode technique to stabilise the system dynamic errors. To improve the learning capability, the FNNC term incorporates an online parameter training methodology, using the gradient descent method and Lyapunov stability theory. Besides, a linear load current observer that estimates the load currents is used to exclude the load current sensors. The proposed SFNN controller and the observer are robust to the filter inductance variations, and their stability analyses are described in detail. The experimental results obtained on a prototype UPS test bed with a TMS320F28335 DSP are presented to validate the feasibility of the proposed scheme. Verification results demonstrate that the proposed control strategy can achieve smaller steady-state error and lower total harmonic distortion when subjected to nonlinear or unbalanced loads compared to the conventional sliding mode control method.

Salinity Trends in the Upper Colorado River Basin Upstream From the Grand Valley Salinity Control Unit, Colorado, 1986-2003

USGS Publications Warehouse

Leib, Kenneth J.; Bauch, Nancy J.

2008-01-01

In 1974, the Colorado River Basin Salinity Control Act was passed into law. This law was enacted to address concerns regarding the salinity content of the Colorado River. The law authorized various construction projects in selected areas or 'units' of the Colorado River Basin intended to reduce the salinity load in the Colorado River. One such area was the Grand Valley Salinity Control Unit in western Colorado. The U. S. Geological Survey has done extensive studies and research in the Grand Valley Salinity Control Unit that provide information to aid the U.S. Bureau of Reclamation and the Natural Resources Conservation Service in determining where salinity-control work may provide the best results, and to what extent salinity-control work was effective in reducing salinity concentrations and loads in the Colorado River. Previous studies have indicated that salinity concentrations and loads have been decreasing downstream from the Grand Valley Salinity Control Unit, and that the decreases are likely the result of salinity control work in these areas. Several of these reports; however, also document decreasing salinity loads upstream from the Grand Valley Salinity Control Unit. This finding was important because only a small amount of salinity-control work was being done in areas upstream from the Grand Valley Salinity Control Unit at the time the findings were reported (late 1990?s). As a result of those previous findings, the U.S. Bureau of Reclamation entered into a cooperative agreement with the U.S. Geological Survey to investigate salinity trends in selected areas bracketing the Grand Valley Salinity Control Unit and regions upstream from the Grand Valley Salinity Control Unit. The results of the study indicate that salinity loads were decreasing upstream from the Grand Valley Salinity Control Unit from 1986 through 2003, but the rates of decrease have slowed during the last 10 years. The average rate of decrease in salinity load upstream from the Grand Valley Salinity Control Unit was 10,700 tons/year. This accounts for approximately 27 percent of the decrease observed downstream from the Grand Valley Salinity Control Unit. Salinity loads were decreasing at the fastest rate (6,950 tons/year) in Region 4, which drains an area between the Colorado River at Cameo, Colorado (station CAMEO) and Colorado River above Glenwood Springs, Colorado (station GLEN) streamflow-gaging stations. Trends in salinity concentration and streamflow were tested at station CAMEO to determine if salinity concentration, streamflow, or both are controlling salinity loads upstream from the Grand Valley Salinity Control Unit. Trend tests of individual ion concentrations were included as potential indicators of what sources (based on mineral composition) may be controlling trends in the upper Colorado. No significant trend was detected for streamflow from 1986 to 2003 at station CAMEO; however, a significant downward trend was detected for salinity concentration. The trend slope indicates that salinity concentration is decreasing at a median rate of about 3.54 milligrams per liter per year. Five major ions (calcium, magnesium, sodium, sulfate, and chloride) were tested for trends. The results indicate that processes within source areas with rock and soil types (or other unidentified sources) bearing calcium, sodium, and sulfate had the largest effect on the downward trend in salinity load upstream from station CAMEO. Downward trends in salinity load resulting from ground-water sources and/or land-use change were thought to be possible reasons for the observed decreases in salinity loads; however, the cause or causes of the decreasing salinity loads are not fully understood. A reduction in the amount of ground-water percolation from Region 4 (resulting from work done through Federal irrigation system improvement programs as well as privately funded irrigation system improvements) has helped reduce annual salinity load from Region 4 by approxima

Predictive control strategy of a gas turbine for improvement of combined cycle power plant dynamic performance and efficiency.

PubMed

Mohamed, Omar; Wang, Jihong; Khalil, Ashraf; Limhabrash, Marwan

2016-01-01

This paper presents a novel strategy for implementing model predictive control (MPC) to a large gas turbine power plant as a part of our research progress in order to improve plant thermal efficiency and load-frequency control performance. A generalized state space model for a large gas turbine covering the whole steady operational range is designed according to subspace identification method with closed loop data as input to the identification algorithm. Then the model is used in developing a MPC and integrated into the plant existing control strategy. The strategy principle is based on feeding the reference signals of the pilot valve, natural gas valve, and the compressor pressure ratio controller with the optimized decisions given by the MPC instead of direct application of the control signals. If the set points for the compressor controller and turbine valves are sent in a timely manner, there will be more kinetic energy in the plant to release faster responses on the output and the overall system efficiency is improved. Simulation results have illustrated the feasibility of the proposed application that has achieved significant improvement in the frequency variations and load following capability which are also translated to be improvements in the overall combined cycle thermal efficiency of around 1.1 % compared to the existing one.

[On evaluating the robot-based experimental system for biomechanical experiment of human knee].

PubMed

Deng, Guoyong; Tian, Lianfang; Bai, Bo; Sun, Hui

2010-02-01

This is a report on how we use the hybrid force-displacement control method to load the human knee and analyze the effect and value of our robot experimental system through the biomechanical experiments of total meniscal resection of human knee. The whole robot control system can load continuously on the specimens, thus overcoming the shortcomings of the traditional loading methods which can only load discretely. In the meantime, by using the robot-based testing system, the force (torque) of the specimens and the spatial position under the force can be measured in real-time, which overcomes the shortcomings caused by the separation of force (torque) measurement from displacement measurement and so greatly improves the measurement accuracy.

Load attenuating passively adaptive wind turbine blade

DOEpatents

Veers, Paul S.; Lobitz, Donald W.

2003-01-07

A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

Load attenuating passively adaptive wind turbine blade

DOEpatents

Veers, Paul S.; Lobitz, Donald W.

2003-01-01

A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

Low glycaemic index, or low glycaemic load, diets for diabetes mellitus.

PubMed

Thomas, Diana; Elliott, Elizabeth J

2009-01-21

The aim of diabetes management is to normalise blood glucose levels, since improved blood glucose control is associated with reduction in development, and progression, of complications. Nutritional factors affect blood glucose levels, however there is currently no universal approach to the optimal dietary treatment for diabetes. There is controversy about how useful the glycaemic index (GI) is in diabetic meal planning. Improved glycaemic control through diet could minimise medications, lessen risk of diabetic complications, improve quality of life and increase life expectancy. To assess the effects of low glycaemic index, or low glycaemic load, diets on glycaemic control in people with diabetes. We performed electronic searches of The Cochrane Library, MEDLINE, EMBASE and CINAHL with no language restriction. We assessed randomised controlled trials of four weeks or longer that compared a low glycaemic index, or low glycaemic load, diet with a higher glycaemic index, or load, or other diet for people with either type 1 or 2 diabetes mellitus, whose diabetes was not already optimally controlled. Two reviewers independently extracted data on study population, intervention and outcomes for each included study, using standardised data extraction forms. Eleven relevant randomised controlled trials involving 402 participants were identified. There was a significant decrease in the glycated haemoglobin A1c (HbA1c) parallel group of trials, the weighted mean difference (WMD) was -0.5% with a 95% confidence interval (CI) of - 0.9 to -0.1, P = 0.02; and in the cross-over group of trials the WMD was -0.5% with a 95% CI of -1.0 to -0.1, P = 0.03. Episodes of hypoglycaemia were significantly fewer with low compared to high GI diet in one trial (difference of -0.8 episodes per patient per month, P < 0.01), and proportion of participants reporting more than 15 hyperglycaemic episodes per month was lower for low-GI diet compared to measured carbohydrate exchange diet in another study (35% versus 66%, P = 0.006). No study reported on mortality, morbidity or costs. A low-GI diet can improve glycaemic control in diabetes without compromising hypoglycaemic events.

Dynamic Modeling, Model-Based Control, and Optimization of Solid Oxide Fuel Cells

NASA Astrophysics Data System (ADS)

Spivey, Benjamin James

2011-07-01

Solid oxide fuel cells are a promising option for distributed stationary power generation that offers efficiencies ranging from 50% in stand-alone applications to greater than 80% in cogeneration. To advance SOFC technology for widespread market penetration, the SOFC should demonstrate improved cell lifetime and load-following capability. This work seeks to improve lifetime through dynamic analysis of critical lifetime variables and advanced control algorithms that permit load-following while remaining in a safe operating zone based on stress analysis. Control algorithms typically have addressed SOFC lifetime operability objectives using unconstrained, single-input-single-output control algorithms that minimize thermal transients. Existing SOFC controls research has not considered maximum radial thermal gradients or limits on absolute temperatures in the SOFC. In particular, as stress analysis demonstrates, the minimum cell temperature is the primary thermal stress driver in tubular SOFCs. This dissertation presents a dynamic, quasi-two-dimensional model for a high-temperature tubular SOFC combined with ejector and prereformer models. The model captures dynamics of critical thermal stress drivers and is used as the physical plant for closed-loop control simulations. A constrained, MIMO model predictive control algorithm is developed and applied to control the SOFC. Closed-loop control simulation results demonstrate effective load-following, constraint satisfaction for critical lifetime variables, and disturbance rejection. Nonlinear programming is applied to find the optimal SOFC size and steady-state operating conditions to minimize total system costs.

Cockpit displayed traffic information and distributed management in air traffic control

NASA Technical Reports Server (NTRS)

Kreifeldt, J. G.

1980-01-01

A graphical display of information (such as surrounding aircraft and navigation routes) in the cockpit on a cathode ray tube has been proposed for improving the safety, orderliness, and expeditiousness of the air traffic control system. An investigation of this method at NASA-Ames indicated a large reduction in controller verbal work load without increasing pilot verbal load; the visual work may be increased. The cockpit displayed traffic and navigation information system reduced response delays permitting pilots to maintain their spacing more closely and precisely than when depending entirely on controller-issued radar vectors and speed command.

The voltage control for self-excited induction generator based on STATCOM

NASA Astrophysics Data System (ADS)

Yan, Dandan; Wang, Feifeng; Pan, Juntao; Long, Weijie

2018-05-01

The small independent induction generator can build up voltage under its remanent magnetizing and excitation capacitance, but it is prone to voltage sag and harmonic increment when running with load. Therefore, the controller for constant voltage is designed based on the natural coordinate system to adjust the static synchronous compensator (STATCOM), which provides two-way dynamic reactive power compensation for power generation system to achieve voltage stability and harmonic suppression. The control strategy is verified on Matlab/Sinmulik, and the results show that the STATCOM under the controller can effectively improve the load capacity and reliability of asynchronous generator.

Lidar-Enhanced Wind Turbine Control: Past, Present, and Future: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scholbrock, Andrew; Fleming, Paul; Wright, Alan

2016-07-01

This paper will look at the development of lidar-enhanced controls and how they have been used for turbine load reduction with pitch actuation, as well as increased energy production with improved yaw control. Ongoing work will also be discussed to show that combining pitch and torque control using feedforward nonlinear model predictive control can lead to both reduced loads and increased energy production. Future work is also proposed on extending individual wind turbine controls to the wind plant level and determining how lidars can be used for control methods to further lower the cost of wind energy by minimizing wakemore » impacts in a wind farm.« less

Compound hydraulic shear-modulated vortex amplifiers

NASA Technical Reports Server (NTRS)

Goldschmied, F. R.

1977-01-01

A novel two-stage shear-modulated hydraulic vortex amplifier (U.S. patent 3,520,317) has been fabricated and put through preliminary steady-state testing at the 1000 psi supply pressure level with flows up to 15 gpm. The invention comprises a conventional fluidic vortex power stage and a shear-modulated pilot stage. In the absence of any mechanical moving parts, water may be used as the hydraulic medium thus opening the way to many underseas applications. At blocked load, a control input from 0 to 150 psi was required to achieve an output from 0 to 900 psi; at wide-open load, a control input of 0 to 120 psi was needed to achieve an output from 0 to 15 gpm. The power stage has been found unsuitable for the proportional control mode because of its nonlinear performance in the intermediate load range and because of strong pressure fluctuations (plus or minus 150 psi) in the intermediate control range. The addition of the shear-modulated pilot stage improves intermediate load linearity.

An improved risk-explicit interval linear programming model for pollution load allocation for watershed management.

PubMed

Xia, Bisheng; Qian, Xin; Yao, Hong

2017-11-01

Although the risk-explicit interval linear programming (REILP) model has solved the problem of having interval solutions, it has an equity problem, which can lead to unbalanced allocation between different decision variables. Therefore, an improved REILP model is proposed. This model adds an equity objective function and three constraint conditions to overcome this equity problem. In this case, pollution reduction is in proportion to pollutant load, which supports balanced development between different regional economies. The model is used to solve the problem of pollution load allocation in a small transboundary watershed. Compared with the REILP original model result, our model achieves equity between the upstream and downstream pollutant loads; it also overcomes the problem of greatest pollution reduction, where sources are nearest to the control section. The model provides a better solution to the problem of pollution load allocation than previous versions.

A quality evaluation of stabilization of rotation frequency of gas-diesel engines when using an adaptive automatic control system

NASA Astrophysics Data System (ADS)

Zhilenkov, A. A.; Efremov, A. A.

2017-02-01

A possibility of quality improvement of stabilization of rotation frequency of the gas-diesels used as prime mover of generator set in the multigenerator units working for abruptly variable load of large power is considered. An evaluation is made on the condition of fuzzy controller use developed and described by the authors in a number of articles. An evaluation has shown that theoretically, the revolution range of a gas-diesel engine may be reduced 25-30 times in case of optimal settings of the controller in the whole power range. The results of modelling showing a considerable quality improvement of transient processes in the investigated system during a sharp change of loading are presented in this article.

Development in helicopter tail boom strake applications in the US

NASA Technical Reports Server (NTRS)

Wilson, John C.; Kelley, Henry L.; Donahue, Cynthia C.; Yenni, Kenneth R.

1988-01-01

The use of a strake or spoiler on a helicopter tail boom to beneficially change helicopter tail boom air loads was suggested in the United States in 1975. The anticipated benefits were a change of tail boom loads to reduce required tail rotor thrust and power and improve directional control. High tail boom air loads experienced by the YAH-64 and described in 1978 led to a wind tunnel investigation of the usefullness of strakes in altering such loads on the AH-64, UH-60, and UH-1 helicopters. The wind tunnel tests of 2-D cross sections of the tail boom of each demonstrated that a strake or strakes would be effective. Several limited test programs with the U.S. Army's OH-58A, AH-64, and UH-60A were conducted which showed the effects of strakes were modest for those helicopters. The most recent flight test program, with a Bell 204B, disclosed that for the 204B the tail boom strake or strakes would provide more than a modest improvement in directional control and reduction in tail rotor power.

Load capacity improvements in nucleic acid based systems using partially open feedback control.

PubMed

Kulkarni, Vishwesh; Kharisov, Evgeny; Hovakimyan, Naira; Kim, Jongmin

2014-08-15

Synthetic biology is facilitating novel methods and components to build in vivo and in vitro circuits to better understand and re-engineer biological networks. Recently, Kim and Winfree have synthesized a remarkably elegant network of transcriptional oscillators in vitro using a modular architecture of synthetic gene analogues and a few enzymes that, in turn, could be used to drive a variety of downstream circuits and nanodevices. However, these oscillators are sensitive to initial conditions and downstream load processes. Furthermore, the oscillations are not sustained since the inherently closed design suffers from enzyme deactivation, NTP fuel exhaustion, and waste product build up. In this paper, we show that a partially open architecture in which an [Symbol: see text]1 adaptive controller, implemented inside an in silico computer that resides outside the wet-lab apparatus, can ensure sustained tunable oscillations in two specific designs of the Kim-Winfree oscillator networks. We consider two broad cases of operation: (1) the oscillator network operating in isolation and (2) the oscillator network driving a DNA tweezer subject to a variable load. In both scenarios, our simulation results show a significant improvement in the tunability and robustness of these oscillator networks. Our approach can be easily adopted to improve the loading capacity of a wide range of synthetic biological devices.

Optimized Controller Design for a 12-Pulse Voltage Source Converter Based HVDC System

NASA Astrophysics Data System (ADS)

Agarwal, Ruchi; Singh, Sanjeev

2017-12-01

The paper proposes an optimized controller design scheme for power quality improvement in 12-pulse voltage source converter based high voltage direct current system. The proposed scheme is hybrid combination of golden section search and successive linear search method. The paper aims at reduction of current sensor and optimization of controller. The voltage and current controller parameters are selected for optimization due to its impact on power quality. The proposed algorithm for controller optimizes the objective function which is composed of current harmonic distortion, power factor, and DC voltage ripples. The detailed designs and modeling of the complete system are discussed and its simulation is carried out in MATLAB-Simulink environment. The obtained results are presented to demonstrate the effectiveness of the proposed scheme under different transient conditions such as load perturbation, non-linear load condition, voltage sag condition, and tapped load fault under one phase open condition at both points-of-common coupling.

Recovery Act. Advanced Load Identification and Management for Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yi; Casey, Patrick; Du, Liang

2014-02-12

In response to the U.S. Department of Energy (DoE)’s goal of achieving market ready, net-zero energy residential and commercial buildings by 2020 and 2025, Eaton partnered with the Department of Energy’s National Renewable Energy Laboratory (NREL) and Georgia Institute of Technology to develop an intelligent load identification and management technology enabled by a novel “smart power strip” to provide critical intelligence and information to improve the capability and functionality of building load analysis and building power management systems. Buildings account for 41% of the energy consumption in the United States, significantly more than either transportation or industrial. Within the buildingmore » sector, plug loads account for a significant portion of energy consumption. Plug load consumes 15-20% of building energy on average. As building managers implement aggressive energy conservation measures, the proportion of plug load energy can increase to as much as 50% of building energy leaving plug loads as the largest remaining single source of energy consumption. This project focused on addressing plug-in load control and management to further improve building energy efficiency accomplished through effective load identification. The execution of the project falls into the following three major aspects; An intelligent load modeling, identification and prediction technology was developed to automatically determine the type, energy consumption, power quality, operation status and performance status of plug-in loads, using electric waveforms at a power outlet level. This project demonstrated the effectiveness of the developed technology through a large set of plug-in loads measurements and testing; A novel “Smart Power Strip (SPS) / Receptacle” prototype was developed to act as a vehicle to demonstrate the feasibility of load identification technology as a low-cost, embedded solution; and Market environment for plug-in load control and management solutions, in particular, advanced power strips (APSs) was studied. The project evaluated the market potential for Smart Power Strips (SPSs) with load identification and the likely impact of a load identification feature on APS adoption and effectiveness. The project also identified other success factors required for widespread APS adoption and market acceptance. Even though the developed technology is applicable for both residential and commercial buildings, this project is focused on effective plug-in load control and management for commercial buildings, accomplished through effective load identification. The project has completed Smart Receptacle (SR) prototype development with integration of Load ID, Control/Management, WiFi communication, and Web Service. Twenty SR units were built, tested, and demonstrated in the Eaton lab; eight SR units were tested in the National Renewable Energy Lab (NREL) for one-month of field testing. Load ID algorithm testing for extended load sets was conducted within the Eaton facility and at local university campuses. This report is to summarize the major achievements, activities, and outcomes under the execution of the project.« less

Effects of crop load on distribution and utilization of 13C and 15N and fruit quality for dwarf apple trees.

PubMed

Ding, Ning; Chen, Qian; Zhu, Zhanling; Peng, Ling; Ge, Shunfeng; Jiang, Yuanmao

2017-10-26

In order to define the effects of fruit crop load on the distribution and utilization of carbon and nitrogen in dwarf apple trees, we conducted three crop load levels (High-crop load, 6 fruits per trunk cross-sectional area (cm 2 , TCA)), Medium-crop load (4 fruits cm -2 TCA), Low-crop load (2 fruits cm -2 TCA)) in 2014 and 2015. The results indicated that the 15 N derived from fertilizer (Ndff) values of fruits decreased with the reduction of crop load, but the Ndff values of annual branches, leaves and roots increased. The plant 15 N-urea utilization rates on Medium and Low-crop load were 1.12-1.35 times higher than the High-crop load. With the reduction of crop load, the distribution rate of 13 C and 15 N in fruits was gradually reduced, but in contrast, the distribution of 13 C and 15 N gradually increased in annual branches, leaves and roots. Compared with High-crop load, the Medium and Low-crop load significantly improved fruit quality p < 0.05. Hence, controlling fruit load effectively regulated the distribution of carbon and nitrogen in plants, improved the nitrogen utilization rate and fruit quality. The appropriate crop load level for mature M.26 interstocks apple orchards was deemed to be 4.0 fruits cm -2 TCA.

EFFICIENCY OPTIMIZATIN CONTROL OF AC INDUCTION MOTORS: INITIAL LABORATORY RESULTS

EPA Science Inventory

The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. This energy optimizer is complemented by a sensorless speed controller that maintains motor shaft re...

Effects of Cognitive Load on Driving Performance: The Cognitive Control Hypothesis.

PubMed

Engström, Johan; Markkula, Gustav; Victor, Trent; Merat, Natasha

2017-08-01

The objective of this paper was to outline an explanatory framework for understanding effects of cognitive load on driving performance and to review the existing experimental literature in the light of this framework. Although there is general consensus that taking the eyes off the forward roadway significantly impairs most aspects of driving, the effects of primarily cognitively loading tasks on driving performance are not well understood. Based on existing models of driver attention, an explanatory framework was outlined. This framework can be summarized in terms of the cognitive control hypothesis: Cognitive load selectively impairs driving subtasks that rely on cognitive control but leaves automatic performance unaffected. An extensive literature review was conducted wherein existing results were reinterpreted based on the proposed framework. It was demonstrated that the general pattern of experimental results reported in the literature aligns well with the cognitive control hypothesis and that several apparent discrepancies between studies can be reconciled based on the proposed framework. More specifically, performance on nonpracticed or inherently variable tasks, relying on cognitive control, is consistently impaired by cognitive load, whereas the performance on automatized (well-practiced and consistently mapped) tasks is unaffected and sometimes even improved. Effects of cognitive load on driving are strongly selective and task dependent. The present results have important implications for the generalization of results obtained from experimental studies to real-world driving. The proposed framework can also serve to guide future research on the potential causal role of cognitive load in real-world crashes.

Modeling and distributed gain scheduling strategy for load frequency control in smart grids with communication topology changes.

PubMed

Liu, Shichao; Liu, Xiaoping P; El Saddik, Abdulmotaleb

2014-03-01

In this paper, we investigate the modeling and distributed control problems for the load frequency control (LFC) in a smart grid. In contrast with existing works, we consider more practical and real scenarios, where the communication topology of the smart grid changes because of either link failures or packet losses. These topology changes are modeled as a time-varying communication topology matrix. By using this matrix, a new closed-loop power system model is proposed to integrate the communication topology changes into the dynamics of a physical power system. The globally asymptotical stability of this closed-loop power system is analyzed. A distributed gain scheduling LFC strategy is proposed to compensate for the potential degradation of dynamic performance (mean square errors of state vectors) of the power system under communication topology changes. In comparison to conventional centralized control approaches, the proposed method can improve the robustness of the smart grid to the variation of the communication network as well as to reduce computation load. Simulation results show that the proposed distributed gain scheduling approach is capable to improve the robustness of the smart grid to communication topology changes. © 2013 ISA. Published by ISA. All rights reserved.

Study on fault diagnosis and load feedback control system of combine harvester

NASA Astrophysics Data System (ADS)

Li, Ying; Wang, Kun

2017-01-01

In order to timely gain working status parameters of operating parts in combine harvester and improve its operating efficiency, fault diagnosis and load feedback control system is designed. In the system, rotation speed sensors were used to gather these signals of forward speed and rotation speeds of intermediate shaft, conveying trough, tangential and longitudinal flow threshing rotors, grain conveying auger. Using C8051 single chip microcomputer (SCM) as processor for main control unit, faults diagnosis and forward speed control were carried through by rotation speed ratio analysis of each channel rotation speed and intermediate shaft rotation speed by use of multi-sensor fused fuzzy control algorithm, and these processing results would be sent to touch screen and display work status of combine harvester. Field trials manifest that fault monitoring and load feedback control system has good man-machine interaction and the fault diagnosis method based on rotation speed ratios has low false alarm rate, and the system can realize automation control of forward speed for combine harvester.

Effect of trace element addition and increasing organic loading rates on the anaerobic digestion of cattle slaughterhouse wastewater.

PubMed

Schmidt, Thomas; McCabe, Bernadette K; Harris, Peter W; Lee, Seonmi

2018-05-18

In this study, anaerobic digestion of slaughterhouse wastewater with the addition of trace elements was monitored for biogas quantity, quality and process stability using CSTR digesters operated at mesophilic temperature. The determination of trace element concentrations was shown to be deficient in Fe, Ni, Co, Mn and Mo compared to recommendations given in the literature. Addition of these trace elements resulted in enhanced degradation efficiency, higher biogas production and improved process stability. Higher organic loading rates and lower hydraulic retention times were achieved in comparison to the control digesters. A critical accumulation of volatile fatty acids was observed at an organic loading rate of 1.82 g L -1  d -1 in the control compared to 2.36 g L -1  d -1 in the digesters with trace element addition. The improved process stability was evident in the final weeks of experimentation, in which control reactors produced 84% less biogas per day compared to the reactors containing trace elements. Copyright © 2018 Elsevier Ltd. All rights reserved.

Research on intelligent power consumption strategy based on time-of-use pricing

NASA Astrophysics Data System (ADS)

Fu, Wei; Gong, Li; Chen, Heli; He, Yu

2017-06-01

In this paper, through the analysis of shortcomings of the current domestic and foreign household power consumption strategy: Passive way of power consumption, ignoring the different priority of electric equipment, neglecting the actual load pressure of the grid, ignoring the interaction with the user, to decrease the peak-valley difference and improve load curve in residential area by demand response (DR technology), an intelligent power consumption scheme based on time-of-use(TOU) pricing for household appliances is proposed. The main contribution of this paper is: (1) Three types of household appliance loads are abstracted from different operating laws of various household appliances, and the control models and DR strategies corresponding to these types are established. (2) The fuzzified processing for the information of TOU price, which is based on the time intervals, is performed to get the price priority, in accordance with such DR events as the maximum restricted load of DR, the time of DR and the duration of interruptible load and so on, the DR control rule and pre-scheduling mechanism are led in. (3) The dispatching sequence of household appliances in the control and scheduling queue are switched and controlled to implement the equilibrium of peak and valley loads. The equilibrium effects and economic benefits of power system by pre-scheduling and DR dispatching are compared and analyzed by simulation example, and the results show that using the proposed household appliance control (HAC) scheme the overall cost of consumers can be reduced and the power system load can be alleviated, so the proposed household appliance control (HAC) scheme is feasible and reasonable.

Drug loading into beta-cyclodextrin granules using a supercritical fluid process for improved drug dissolution.

PubMed

Hussein, Khaled; Türk, Michael; Wahl, Martin A

2008-03-03

To improve dissolution properties of drugs, a supercritical fluid (SCF) technique was used to load these drugs into a solid carrier. In this study, granules based on beta-cyclodextrin (betaCD) were applied as a carrier for poor water-soluble drug and loaded with a model drug (ibuprofen) using two different procedures: controlled particle deposition (CPD), SCF process and solution immersion (SI) as a conventional method for comparison. Using the CPD technique, 17.42+/-2.06wt.% (n=3) ibuprofen was loaded into betaCD-granules, in contrast to only 3.8+/-0.15wt.% (n=3) in the SI-product. The drug loading was confirmed as well by reduction of the BET surface area for the CPD-product (1.134+/-0.07m(2)/g) compared to the unloaded-granules (1.533+/-0.031m(2)/g). Such a reduction was not seen in the SI-product (1.407+/-0.048m(2)/g). The appearance of an endothermic melting peak at 77 degrees C and X-ray patterns representing ibuprofen in drug-loaded granules can be attributed to the amount of ibuprofen loaded in its crystalline form. A significant increase in drug dissolution was achieved by either drug-loading procedures compared to the unprocessed ibuprofen. In this study, the CPD technique, a supercritical fluid process avoiding the use of toxic or organic solvents was successfully applied to load drug into solid carriers, thereby improving the water-solubility of the drug.

Non-Static error tracking control for near space airship loading platform

NASA Astrophysics Data System (ADS)

Ni, Ming; Tao, Fei; Yang, Jiandong

2018-01-01

A control scheme based on internal model with non-static error is presented against the uncertainty of the near space airship loading platform system. The uncertainty in the tracking table is represented as interval variations in stability and control derivatives. By formulating the tracking problem of the uncertainty system as a robust state feedback stabilization problem of an augmented system, sufficient condition for the existence of robust tracking controller is derived in the form of linear matrix inequality (LMI). Finally, simulation results show that the new method not only has better anti-jamming performance, but also improves the dynamic performance of the high-order systems.

End-User Tools Towards AN Efficient Electricity Consumption: the Dynamic Smart Grid

NASA Astrophysics Data System (ADS)

Kamel, Fouad; Kist, Alexander A.

2010-06-01

Growing uncontrolled electrical demands have caused increased supply requirements. This causes volatile electrical markets and has detrimental unsustainable environmental impacts. The market is presently characterized by regular daily peak demand conditions associated with high electricity prices. A demand-side response system can limit peak demands to an acceptable level. The proposed scheme is based on energy demand and price information which is available online. An online server is used to communicate the information of electricity suppliers to users, who are able to use the information to manage and control their own demand. A configurable, intelligent switching system is used to control local loads during peak events and mange the loads at other times as necessary. The aim is to shift end user loads towards periods where energy demand and therefore also prices are at the lowest. As a result, this will flatten the load profile and avoiding load peeks which are costly for suppliers. The scheme is an endeavour towards achieving a dynamic smart grid demand-side-response environment using information-based communication and computer-controlled switching. Diffusing the scheme shall lead to improved electrical supply services and controlled energy consumption and prices.

Effect of respiratory muscle training on GLUT-4 in the sheep diaphragm.

PubMed

Bhandari, A; Xia, Y; Cortright, R; Dohm, G L; Bazzy, A R

2000-08-01

Endurance exercise training is associated with enhanced glucose uptake and hence improvement in carbohydrate metabolism. Glucose transport (GLUT) membrane proteins are regulated by a variety of physiological stimuli, including exercise. In limb muscle, both acute exercise and endurance training enhance the expression of the skeletal muscle transporter, GLUT-4. The purpose of this study is to determine whether chronic loading enhances GLUT-4 expression in the diaphragm. The effect of chronic inspiratory flow resistive (IFR) loading on diaphragm GLUT-4 was studied in a model of respiratory muscle endurance training in sheep. IFR loads (resistance 50-100 cm H2O x L(-1) x s(-1)) were maintained for 3 h x d(-1), 5-6 d x wk(-1) for 3 wk. Loading was adjusted so that PaO2 was >60 Torr and PaCO2 <45 Torr in room air. Six untrained sheep were used as controls. GLUT-4 protein and mRNA were analyzed by Western and Northern analysis respectively. GLUT-4 protein levels were two-fold greater in trained animals when compared with controls (P < 0.01). GLUT-4 mRNA levels in the trained muscles was not significantly different from controls. We conclude that in the sheep diaphragm, chronic IFR loading increases GLUT-4 protein levels. This increase may be one of the mechanisms contributing to the improved respiratory muscle endurance previously demonstrated in this animal model of respiratory muscle training.

Low cognitive load and reduced arousal impede practice effects on executive functioning, metacognitive confidence and decision making.

PubMed

Jackson, Simon A; Kleitman, Sabina; Aidman, Eugene

2014-01-01

The present study investigated the effects of low cognitive workload and the absence of arousal induced via external physical stimulation (motion) on practice-related improvements in executive (inhibitory) control, short-term memory, metacognitive monitoring and decision making. A total of 70 office workers performed low and moderately engaging passenger tasks in two successive 20-minute simulated drives and repeated a battery of decision making and inhibitory control tests three times—before, between and after these drives. For half the participants, visual simulation was synchronised with (moderately arousing) motion generated through LAnd Motion Platform, with vibration levels corresponding to a well-maintained unsealed road. The other half performed the same simulated drive without motion. Participants' performance significantly improved over the three test blocks, which is indicative of typical practice effects. The magnitude of these improvements was the highest when both motion and moderate cognitive load were present. The same effects declined either in the absence of motion (low arousal) or following a low cognitive workload task, thus suggesting two distinct pathways through which practice-related improvements in cognitive performance may be hampered. Practice, however, degraded certain aspects of metacognitive performance, as participants became less likely to detect incorrect decisions in the decision-making test with each subsequent test block. Implications include consideration of low cognitive load and arousal as factors responsible for performance decline and targets for the development of interventions/strategies in low load/arousal conditions such as autonomous vehicle operations and highway driving.

Controlled Release in Transdermal Pressure Sensitive Adhesives using Organosilicate Nanocomposites

PubMed Central

Shaikh, Sohel; Birdi, Anil; Qutubuddin, Syed; Lakatosh, Eric; Baskaran, Harihara

2010-01-01

Polydimethyl siloxane (PDMS) based pressure sensitive adhesives (PSA) incorporating organo-clays at different loadings were fabricated via solution casting. Partially exfoliated nanocomposites were obtained for the hydroxyl terminated PDMS in ethyl acetate solvent as determined by X-ray diffraction (XRD) and atomic force microscopy (AFM). Drug release studies showed that the initial burst release was substantially reduced and the drug release could be controlled by the addition of organo-clay. Shear strength and shear adhesion failure temperature (SAFT) measurements indicated substantial improvement in adhesive properties of the PSA nanocomposite adhesives. Shear strength showed more than 200 % improvement at the lower clay loadings and the SAFT increased by about 21% due to the reinforcement provided by the nano-dispersed clay platelets. It was found that by optimizing the level of the organosilicate additive to the polymer matrix, superior control over drug release kinetics and simultaneous improvements in adhesive properties could be attained for a transdermal PSA formulation. PMID:17786555

Opportunities to improve the conversion of food waste to lactate: Fine-tuning secondary factors.

PubMed

RedCorn, Raymond; Engelberth, Abigail S

2017-11-01

Extensive research has demonstrated the potential for bioconversion of food waste to lactate, with major emphasis on adjusting temperature, pH, and loading rate of the fermentation. Each of these factors has a significant effect on lactate production; however, additional secondary factors have received little attention. Here we investigate three additional factors where opportunities exist for process improvement: freezing of samples during storage, discontinuous pH control, and holdover of fermentation broth between fermentations. Freezing samples prior to fermentation was shown to reduce the production rate of lactate by 8%, indicating freeze-thaw should be avoided in experiments. Prior work indicated a trade-off in pH control strategies, where discontinuous pH control correlated with higher lactate accumulation while continuous pH control correlated with higher production rate. Here we demonstrate that continuous pH control can achieve both higher lactate accumulation and higher production rate. Finally, holding over fermentation broth was shown to be a simple method to improve production rate (by 18%) at high food waste loading rates (>140 g volatile solids L -1 ) but resulted in lower lactate accumulation (by 17%). The results inform continued process improvements within the waste treatment of food waste through fermentation to lactic acid.

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

7 CFR 1710.252 - Construction work plans-power supply borrowers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... operating systems of supporting power pools and to connect with adjacent power suppliers; (4) Improvements..., new substations and substation improvements and replacements, and Systems Control and Data Acquisition... include studies of load flows, voltage regulation, and stability characteristics to demonstrate system...

Cholestanol-loaded-cyclodextrin improves the quality of stallion spermatozoa after cryopreservation.

PubMed

Moraes, E A; Matos, W C G; Graham, J K; Ferrari, W D

2015-07-01

This study was to compare the effect of adding cholesterol or cholestanol loaded cyclodextrins in stallion sperm prior to cryopreservation to optimize sperm cryosurvival. Ejaculates from each of eight stallions were diluted to 120 million cells in a S-MEDIUM diluent. The diluted sperm were sub-divided into three treatments: no additive (control); 0.75mg of cyclodextrin pre-loaded with cholesterol (CLC)/120 million sperm (positive control); 1.5mg CLC/120 million sperm; 0.75mg of cyclodextrin pre-loaded with cholestanol (CnLC)/120 million sperm; and 1.5mg CnLC/120 million sperm. To set the experiments, the treated sperm were incubated for 15min at 22°C to allow for the incorporation of cholesterol or cholestanol. In each experiment, treated sperm incubated for 15min at 22°C to allow for incorporation of cholesterol or cholestanol. The samples were then diluted 1:5 (v/v) with Lactose-Egg Yolk diluent and cooled to 5°C over a 2h period. Loaded into 0.25ml polyvinylchloride straws, frozen in liquid nitrogen vapor for 10min, and then plunged into liquid nitrogen until further use. Higher percentages of motile sperm and viable cells were achieved after thawing for stallion sperm treated with CLC and CnLC compared to control (P<0.05). Addition of CnLC also resulted in more number sperm binding to chicken egg perivitelline membrane (CEPM) after cryopreservation than cholestanol and control sperm (P<0.05). In conclusion, CnLC and CLC improved the percentage of post-thaw motility of equine sperm and CnLC provided greater binding efficiency. Copyright © 2015 Elsevier B.V. All rights reserved.

Nandrolone decanoate and load increase remodeling and strength in human supraspinatus bioartificial tendons.

PubMed

Triantafillopoulos, Ioannis K; Banes, Albert J; Bowman, Karl F; Maloney, Melissa; Garrett, William E; Karas, Spero G

2004-06-01

To date, no studies document the effect of anabolic steroids on rotator cuff tendons. Controlled laboratory study. Anabolic steroids enhance remodeling and improve the biomechanical properties of bioartificially engineered human supraspinatus tendons. Bioartificial tendons were treated with either nandrolone decanoate (nonload, steroid, n = 18), loading (load, nonsteroid, n = 18), or both (load, steroid, n = 18). A control group received no treatment (nonload, nonsteroid [NLNS], n = 18). Bioartificial tendons' remodeling was assessed by daily scanning, cytoskeletal organization by staining, matrix metalloproteinase-3 levels by ELISA assay, and biomechanical properties by load-to-failure testing. The load, steroid group showed the greatest remodeling and the best organized actin cytoskeleton. Matrix metallo-proteinase-3 levels in the load, steroid group were greater than those of the nonload, nonsteroid group (P <.05). Ultimate stress and ultimate strain in the load, steroid group were greater than those of the nonload, nonsteroid and nonload, steroid groups (P <.05). The strain energy density in the load, steroid group was greater when compared to other groups (P <.05). Nandrolone decanoate and load acted synergistically to increase matrix remodeling and biomechanical properties of bioartificial tendons. Data suggest anabolic steroids may enhance production of bioartificial tendons and rotator cuff tendon healing in vitro. More research is necessary before such clinical use is recommended.

High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

DOEpatents

Shimer, D.W.; Lange, A.C.

1995-05-23

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1995-01-01

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

Adaptive servo control for umbilical mating

NASA Technical Reports Server (NTRS)

Zia, Omar

1988-01-01

Robotic applications at Kennedy Space Center are unique and in many cases require the fime positioning of heavy loads in dynamic environments. Performing such operations is beyond the capabilities of an off-the-shelf industrial robot. Therefore Robotics Applications Development Laboratory at Kennedy Space Center has put together an integrated system that coordinates state of the art robotic system providing an excellent easy to use testbed for NASA sensor integration experiments. This paper reviews the ways of improving the dynamic response of the robot operating under force feedback with varying dynamic internal perturbations in order to provide continuous stable operations under variable load conditions. The goal is to improve the stability of the system with force feedback using the adaptive control feature of existing system over a wide range of random motions. The effect of load variations on the dynamics and the transfer function (order or values of the parameters) of the system has been investigated, more accurate models of the system have been determined and analyzed.

Solar plus: Optimization of distributed solar PV through battery storage and dispatchable load in residential buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Cutler, Dylan; Ardani, Kristen

As utility electricity rates evolve, pairing solar photovoltaic (PV) systems with battery storage has potential to ensure the value proposition of residential solar by mitigating economic uncertainty. In addition to batteries, load control technologies can reshape customer load profiles to optimize PV system use. The combination of PV, energy storage, and load control provides an integrated approach to PV deployment, which we call 'solar plus'. The U.S. National Renewable Energy Laboratory's Renewable Energy Optimization (REopt) model is utilized to evaluate cost-optimal technology selection, sizing, and dispatch in residential buildings under a variety of rate structures and locations. The REopt modelmore » is extended to include a controllable or 'smart' domestic hot water heater model and smart air conditioner model. We find that the solar plus approach improves end user economics across a variety of rate structures - especially those that are challenging for PV - including lower grid export rates, non-coincident time-of-use structures, and demand charges.« less

Solar plus: Optimization of distributed solar PV through battery storage and dispatchable load in residential buildings

DOE PAGES

O'Shaughnessy, Eric; Cutler, Dylan; Ardani, Kristen; ...

2018-01-11

As utility electricity rates evolve, pairing solar photovoltaic (PV) systems with battery storage has potential to ensure the value proposition of residential solar by mitigating economic uncertainty. In addition to batteries, load control technologies can reshape customer load profiles to optimize PV system use. The combination of PV, energy storage, and load control provides an integrated approach to PV deployment, which we call 'solar plus'. The U.S. National Renewable Energy Laboratory's Renewable Energy Optimization (REopt) model is utilized to evaluate cost-optimal technology selection, sizing, and dispatch in residential buildings under a variety of rate structures and locations. The REopt modelmore » is extended to include a controllable or 'smart' domestic hot water heater model and smart air conditioner model. We find that the solar plus approach improves end user economics across a variety of rate structures - especially those that are challenging for PV - including lower grid export rates, non-coincident time-of-use structures, and demand charges.« less

Delivery of Flightless I Neutralizing Antibody from Porous Silicon Nanoparticles Improves Wound Healing in Diabetic Mice.

PubMed

Turner, Christopher T; McInnes, Steven J P; Melville, Elizabeth; Cowin, Allison J; Voelcker, Nicolas H

2017-01-01

Flightless I (Flii) is elevated in human chronic wounds and is a negative regulator of wound repair. Decreasing its activity improves healing responses. Flii neutralizing antibodies (FnAbs) decrease Flii activity in vivo and hold significant promise as healing agents. However, to avoid the need for repeated application in a clinical setting and to protect the therapeutic antibody from the hostile environment of the wound, suitable delivery vehicles are required. In this study, the use of porous silicon nanoparticles (pSi NPs) is demonstrated for the controlled release of FnAb to diabetic wounds. We achieve FnAb loading regimens exceeding 250 µg antibody per mg of vehicle. FnAb-loaded pSi NPs increase keratinocyte proliferation and enhance migration in scratch wound assays. Release studies confirm the functionality of the FnAb in terms of Flii binding. Using a streptozotocin-induced model of diabetic wound healing, a significant improvement in healing is observed for mice treated with FnAb-loaded pSi NPs compared to controls, including FnAb alone. FnAb-loaded pSi NPs treated with proteases show intact and functional antibody for up to 7 d post-treatment, suggesting protection of the antibodies from proteolytic degradation in wound fluid. pSi NPs may therefore enable new therapeutic approaches for the treatment of diabetic ulcers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flight Test of an Adaptive Controller and Simulated Failure/Damage on the NASA NF-15B

NASA Technical Reports Server (NTRS)

Buschbacher, Mark; Maliska, Heather

2006-01-01

The method of flight-testing the Intelligent Flight Control System (IFCS) Second Generation (Gen-2) project on the NASA NF-15B is herein described. The Gen-2 project objective includes flight-testing a dynamic inversion controller augmented by a direct adaptive neural network to demonstrate performance improvements in the presence of simulated failure/damage. The Gen-2 objectives as implemented on the NASA NF-15B created challenges for software design, structural loading limitations, and flight test operations. Simulated failure/damage is introduced by modifying control surface commands, therefore requiring structural loads measurements. Flight-testing began with the validation of a structural loads model. Flight-testing of the Gen-2 controller continued, using test maneuvers designed in a sequenced approach. Success would clear the new controller with respect to dynamic response, simulated failure/damage, and with adaptation on and off. A handling qualities evaluation was conducted on the capability of the Gen-2 controller to restore aircraft response in the presence of a simulated failure/damage. Control room monitoring of loads sensors, flight dynamics, and controller adaptation, in addition to postflight data comparison to the simulation, ensured a safe methodology of buildup testing. Flight-testing continued without major incident to accomplish the project objectives, successfully uncovering strengths and weaknesses of the Gen-2 control approach in flight.

Evaluation of load tracks and wear of two sets of bearings from space shuttle main engine high pressure oxygen turbopumps

NASA Technical Reports Server (NTRS)

Kannel, J. W.; Dufrane, K. F.

1985-01-01

Bearings supporting the rotor in the High Pressure Oxygen Turbopump (HPOTP) were examined. The No. 1 bearings from both units were in good condition and had successfully completed 5000 seconds of operation. The No. 2 bearings, which were in service the same length of time, were significantly degraded in the form of ball wear, race pitting, and damage from high axial loads. The No. 3 and 4 bearings were in generally acceptable condition. The general conclusion from the examinations was that improved cooling on the No. 2 bearings and further improvements in controlling axial and radial load would likely result in the HPOTP meeting the qualification test results.

A review of failure models for unidirectional ceramic matrix composites under monotonic loads

NASA Technical Reports Server (NTRS)

Tripp, David E.; Hemann, John H.; Gyekenyesi, John P.

1989-01-01

Ceramic matrix composites offer significant potential for improving the performance of turbine engines. In order to achieve their potential, however, improvements in design methodology are needed. In the past most components using structural ceramic matrix composites were designed by trial and error since the emphasis of feasibility demonstration minimized the development of mathematical models. To understand the key parameters controlling response and the mechanics of failure, the development of structural failure models is required. A review of short term failure models with potential for ceramic matrix composite laminates under monotonic loads is presented. Phenomenological, semi-empirical, shear-lag, fracture mechanics, damage mechanics, and statistical models for the fast fracture analysis of continuous fiber unidirectional ceramic matrix composites under monotonic loads are surveyed.

Impact of loaded sit-to-stand exercises at different speeds on the physiological cost of walking in children with spastic diplegia: A single-blind randomized clinical trial.

PubMed

Kusumoto, Yasuaki; Nitta, Osamu; Takaki, Kenji

2016-10-01

In the present study, we aimed to determine whether similarly loaded sit-to-stand exercises at different speeds improve the physiological cost of walking in children with spastic diplegia. This design was a single-blind randomized clinical trial. Sixteen children with cerebral palsy (CP), aged 12-18 years, with a diagnosis of spastic diplegia, were randomly allocated to a slow loaded sit-to-stand exercise group (n=8) and a self-paced loaded sit-to-stand exercise group (n=8). Loaded sit-to-stand exercise was conducted at home for 15min, 4 sets per day, 3-4days per week, for 6 weeks. The patients were evaluated immediately before the intervention and after the training. Lower limb muscle strength using a hand-held dynamometer, selective voluntary motor control using SCALE, 6-min walk distance (6MWD), and Physiological Cost Index (PCI) were measured. The 6MWD showed a significant difference before and after intervention. PCI showed a significant difference between the two groups and the two time points. 6MWD and the PCI improved after intervention in the slow sit-to-stand exercise group. Compared to loaded sit-to-stand exercise at a regular speed, slow low-loaded sit-to-stand exercise improved the 6MWD and PCI in children with CP, suggesting that this decrease in speed during exercise improves the physiological cost of walking in these children. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improving the controlled release of water-insoluble emodin from amino-functionalized mesoporous silica

NASA Astrophysics Data System (ADS)

Xu, Yunqiang; Wang, Chunfeng; Zhou, Guowei; Wu, Yue; Chen, Jing

2012-06-01

Several types of amino-functionalized mesoporous silica, including F5-SBA-15, F10-SBA-15, and F15-SBA-15 were prepared through co-condensation of tetraethoxysilane (TEOS) and (3-aminopropyl)triethoxysilane (APTES) in varying molar ratios (5 mol%, 10 mol%, and 15 mol%) via a hydrothermal process. The materials obtained were characterized by means of small-angle X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption, Fourier transformed infrared spectra, and X-ray photoelectron spectroscopy. Increasing APTES molar ratios decreased the degree of orderliness of the functionalized mesoporous silica. Pure and amino-functionalized SBA-15 samples were employed as supports for the controlled release of water-insoluble drug emodin. Loading experiments showed that drug loading capacities mainly depended on the surface areas and pore diameters of the carriers. Controlled release profiles of emodin-loaded samples were studied in phosphate buffered saline (PBS, pH 7.4), and results indicated that the emodin release rate could be controlled by surface amino-functionalized carriers. Emodin loaded on functionalized mesoporous supports exhibited a lower release rate than that of loaded on pure SBA-15, emodin loaded on F10-SBA-15 showed the smallest release amount (71.74 wt%) after stirring in PBS for 60 h. Findings suggest that functionalized mesoporous SBA-15 is a promising carrier for achieving prolonged release time periods.

Research on H2 speed governor for diesel engine of marine power station

NASA Astrophysics Data System (ADS)

Huang, Man-Lei

2007-09-01

The frequency stability of a marine power system is determined by the dynamic characteristic of the diesel engine speed regulation system in a marine power station. In order to reduce the effect of load disturbances and improve the dynamic precision of a diesel engine speed governor, a controller was designed for a diesel engine speed regulation system using H2 control theory. This transforms the specifications of the system into a standard H2 control problem. Firstly, the mathematical model of a diesel engine speed regulation system using an H2 speed governor is presented. To counter external disturbances and model uncertainty, the design of an H2 speed governor rests on the problem of mixed sensitivity. Computer simulation verified that the H2 speed governor improves the dynamic precision of a system and the ability to adapt to load disturbances, thus enhancing the frequency stability of marine power systems.

Wrinkling and collapse of mesh reinforced membrane inflated beam under bending

NASA Astrophysics Data System (ADS)

Tao, Qiang; Wang, Changguo; Xue, Zhiming; Xie, Zhimin; Tan, Huifeng

2016-11-01

A novel concept of mesh reinforced membrane (MRM) is proposed in this paper. The tensile collapse mechanism of MRM is elucidated based on three obvious deformed stages. An improved Shell-Membrane model is used to predict the wrinkling and collapse of MRM inflated beam which is verified by a non-contact experiment based on the digital image correlation technique. Further the wrinkling details including the wrinkling evolution, pattern, shape, stress distribution are simulated to evaluate the functions of MRM for loading-carrying capacity of inflated beam. Pressure resistant performance of inflated beam was studied at last. The results revealed that MRM shows a great improvement on the collapse moment of inflated beam. MRM contributes to restrain wrinkling evolution by changing the transfer path of loadings which results from dispersing stress distribution and changing wrinkling pattern. The results show good references to the wrinkling control and the improvement of load-carrying capacity of inflated beam.

Improving mechanical properties of maxillary complete dentures through a bioinspired engineering design.

PubMed

White, James A P; Bond, Ian P; Jagger, Daryll C

2011-01-01

This study investigated how ribbed design features, including palatal rugae, may be used to significantly improve the structural performance of a maxillary denture under load. A computer-aided design model of a generic maxillary denture, incorporating various rib features, was created and imported into a finite element analysis program. The denture and ribbed features were assigned the material properties of standard denture acrylic resin, and load was applied in two different ways: the first simulating a three-point flexural bend of the posterior section and the second simulating loading of the entire palatal region. To investigate the combined use of ribbing and reinforcement, the same simulations were repeated with the ribbed features having a Young modulus two orders of magnitude greater than denture acrylic resin. For a prescribed load, total displacements of tracking nodes were compared to those of a control denture (without ribbing) to assess relative denture rigidity. When subjected to flexural loading, an increase in rib depth was seen to result in a reduction of both the transverse displacement of the last molar and vertical displacement at the centerline. However, ribbed features assigned the material properties of denture acrylic resin require a depth that may impose on speech and bolus propulsion before significant improvements are observed. The use of ribbed features, when made from a significantly stiffer material (eg, fiber-reinforced polymer) and designed to mimic palatal rugae, offer an acceptable method of providing significant improvements in rigidity to a maxillary denture under flexural load.

Morphometrical investigations on the reproductive activity of the ovaries in rats subjected to immobilization and to motion activity

NASA Technical Reports Server (NTRS)

Konstantinov, N.; Cheresharov, L.; Toshkova, S.

1982-01-01

Wistar-strain white female rats were divided into three groups, with the first group subjected to motion loading, the second used as control, and the third group was immobilized. A considerable reduction in numbers of corpora lutea was observed in the immobilized group, together with smaller numbers of embryos, high percent of embryo mortality, fetal growth retardation, and endometrium disorders. The control group showed no deviation from normal conditions, and there was slight improvement in reproductive activity of animals under motion loading.

Helicopter Pitch-Control Mechanism Reduces Vibration

NASA Technical Reports Server (NTRS)

Lemont, H.

1986-01-01

Large forces accommodated without increasing weight of helicopter structure. New mechanism yields stiffer control and improves accuracy of pitch changes under load. As result, heavy casting not for gearbox, nor extra reinforcing members needed for fuselage bulkheads, stringers, skin, and other parts. In new mechanism, reaction forces developed in rotor hub. Long load paths to gearbox and fuselage elminated. Reaction member rigidly attached to hub and rotates with it. At lower end of reaction member, bearing forms bridge to fuselage through stationary beam and antirotation link. Beam connected to reaction plate through rods.

[Research of joint-robotics-based design of biomechanics testing device on human spine].

PubMed

Deng, Guoyong; Tian, Lianfang; Mao, Zongyuan

2009-12-01

This paper introduces the hardware and software of a biomechanical robot-based testing device. The bottom control orders, posture and torque data transmission, and the control algorithms are integrated in a unified visual control platform by Visual C+ +, with easy control and management. By using hybrid force-displacement control method to load the human spine, we can test the organizational structure and the force state of the FSU (Functional spinal unit) well, which overcomes the shortcomings due to the separation of the force and displacement measurement, thus greatly improves the measurement accuracy. Also it is esay to identify the spinal degeneration and the load-bearing impact on the organizational structure of the FSU after various types of surgery.

Fuzzy control of power converters based on quasilinear modelling

NASA Astrophysics Data System (ADS)

Li, C. K.; Lee, W. L.; Chou, Y. W.

1995-03-01

Unlike feedback control by the fuzzy PID method, a new fuzzy control algorithm based on quasilinear modelling of the DC-DC converter is proposed. Investigation is carried out using a buck-boost converter. Simulation results demonstrated that the converter can be regulated with improved performance even when subjected to input disturbance and load variation.

Hysteresis Control of Parallel-Connected Hybrid Inverters

DTIC Science & Technology

2005-09-01

92 C. MILITARY APPLICATIONS .....................................................................92 D...unbalanced to replicate the “real-world” application of the controller. Other areas of the controller could be changed to improve the fidelity of the load...a chip to perform the complex mathematics to transform from one reference frame to another while automatically adjusting the filter parameters. The

Improved reliability of wind turbine towers with active tuned mass dampers (ATMDs)

NASA Astrophysics Data System (ADS)

Fitzgerald, Breiffni; Sarkar, Saptarshi; Staino, Andrea

2018-04-01

Modern multi-megawatt wind turbines are composed of slender, flexible, and lightly damped blades and towers. These components exhibit high susceptibility to wind-induced vibrations. As the size, flexibility and cost of the towers have increased in recent years, the need to protect these structures against damage induced by turbulent aerodynamic loading has become apparent. This paper combines structural dynamic models and probabilistic assessment tools to demonstrate improvements in structural reliability when modern wind turbine towers are equipped with active tuned mass dampers (ATMDs). This study proposes a multi-modal wind turbine model for wind turbine control design and analysis. This study incorporates an ATMD into the tower of this model. The model is subjected to stochastically generated wind loads of varying speeds to develop wind-induced probabilistic demand models for towers of modern multi-megawatt wind turbines under structural uncertainty. Numerical simulations have been carried out to ascertain the effectiveness of the active control system to improve the structural performance of the wind turbine and its reliability. The study constructs fragility curves, which illustrate reductions in the vulnerability of towers to wind loading owing to the inclusion of the damper. Results show that the active controller is successful in increasing the reliability of the tower responses. According to the analysis carried out in this paper, a strong reduction of the probability of exceeding a given displacement at the rated wind speed has been observed.

Dynamic Response during PEM Fuel Cell Loading-up

PubMed Central

Pei, Pucheng; Yuan, Xing; Gou, Jun; Li, Pengcheng

2009-01-01

A study on the effects of controlling and operating parameters for a Proton Exchange Membrane (PEM) fuel cell on the dynamic phenomena during the loading-up process is presented. The effect of the four parameters of load-up amplitudes and rates, operating pressures and current levels on gas supply or even starvation in the flow field is analyzed based accordingly on the transient characteristics of current output and voltage. Experiments are carried out in a single fuel cell with an active area of 285 cm2. The results show that increasing the loading-up amplitude can inevitably increase the possibility of gas starvation in channels when a constant flow rate has been set for the cathode; With a higher operating pressure, the dynamic performance will be improved and gas starvations can be relieved. The transient gas supply in the flow channel during two loading-up mode has also been discussed. The experimental results will be helpful for optimizing the control and operation strategies for PEM fuel cells in vehicles.

Postteneral Protein Feeding may Improve Biological Control Efficiency of Aphytis lingnanensis and Aphytis melinus

PubMed Central

Vanaclocha, Pilar; Papacek, Dan; Verdú, Maria Jesús; Urbaneja, Alberto

2014-01-01

Abstract The augmentative releases of mass-reared Aphytis spp. (Hymenoptera: Aphelinidae) parasitoids are widely used against armored scales. The nutritional status and the initial egg load of Aphytis spp. females are key to their success as biological control agents. For these reasons, this work focuses on the study of providing a protein feed to Aphytis lingnanensis (Compere) and A. melinus DeBach to improve the egg load before their release. The addition of protein to a honey diet during the first 2 d after the adult parasitoid emergence increased the initial egg load in both species of parasitoids by more than five eggs. Furthermore, the addition of protein increased the total number of eggs laid by A. lingnanensis on oleander scale, Aspidiotus nerii Bouché (Hemiptera: Diaspididae). In contrast, this effect was not observed on A. melinus probably because A. nerii is considered a suboptimal host for this parasitoid. The host-feeding activities of the two Aphytis species were differentially affected by the addition of protein to their diets. These results may have direct implications for augmentative biological control programs, especially during transportation from insectaries to the field, a period of time when parasitoids are deprived of hosts. PMID:25502042

Low Cognitive Load and Reduced Arousal Impede Practice Effects on Executive Functioning, Metacognitive Confidence and Decision Making

PubMed Central

Jackson, Simon A.; Kleitman, Sabina; Aidman, Eugene

2014-01-01

The present study investigated the effects of low cognitive workload and the absence of arousal induced via external physical stimulation (motion) on practice-related improvements in executive (inhibitory) control, short-term memory, metacognitive monitoring and decision making. A total of 70 office workers performed low and moderately engaging passenger tasks in two successive 20-minute simulated drives and repeated a battery of decision making and inhibitory control tests three times – before, between and after these drives. For half the participants, visual simulation was synchronised with (moderately arousing) motion generated through LAnd Motion Platform, with vibration levels corresponding to a well-maintained unsealed road. The other half performed the same simulated drive without motion. Participants’ performance significantly improved over the three test blocks, which is indicative of typical practice effects. The magnitude of these improvements was the highest when both motion and moderate cognitive load were present. The same effects declined either in the absence of motion (low arousal) or following a low cognitive workload task, thus suggesting two distinct pathways through which practice-related improvements in cognitive performance may be hampered. Practice, however, degraded certain aspects of metacognitive performance, as participants became less likely to detect incorrect decisions in the decision-making test with each subsequent test block. Implications include consideration of low cognitive load and arousal as factors responsible for performance decline and targets for the development of interventions/strategies in low load/arousal conditions such as autonomous vehicle operations and highway driving. PMID:25549327

Design and characterization of Amoitone B-loaded nanostructured lipid carriers for controlled drug release.

PubMed

Luan, Jingjing; Zhang, Dianrui; Hao, Leilei; Li, Caiyun; Qi, Lisi; Guo, Hejian; Liu, Xinquan; Zhang, Qiang

2013-11-01

Amoitone B, a novel compound chemically synthesized as the analogue of cytosporone B, has been proved to own superior affinity with Nur77 than its parent compound and exhibit notable anticancer activity. However, its application is seriously restricted due to the water-insolubility and short biological half-time. The aim of this study was to construct an effective delivery system for Amoitone B to realize sustained release, thus prolong drug circulation time in body and improve the bioavailability. Nanostructured lipid carriers (NLC) act as a new type of colloidal drug delivery system, which offer the advantages of improved drug loading and sustained release. Amoitone B-loaded NLC (AmB-NLC) containing glyceryl monostearate (GMS) and various amounts of medium chain triglycerides (MCT) were successfully prepared by emulsion-evaporation and low temperature-solidification technology with a particle size of about 200 nm and a zeta potential value of about -20 mV. The results of X-ray diffraction and DSC analysis showed amorphous crystalline state of Amoitone B in NLC. Furthermore, the drug entrapment efficacy (EE) was improved compared with solid lipid nanoparticles (SLN). The EE range was from 71.1% to 84.7%, enhanced with the increase of liquid lipid. In vitro drug release studies revealed biphasic drug release patterns with burst release initially and prolonged release afterwards and the release was accelerated with augment of liquid lipid. These results demonstrated that AmB-NLC could be a promising delivery system to control drug release and improve loading capacity, thus prolong drug action time in body and enhance the bioavailability.

Effects of walking with a shopping trolley on spinal posture and loading in subjects with neurogenic claudication.

PubMed

Comer, Christine M; White, Derrick; Conaghan, Philip G; Bird, Howard A; Redmond, Anthony C

2010-10-01

To explore possible mechanisms underpinning symptom relief and improved walking tolerance in patients with neurogenic claudication (NC) when pushing a shopping trolley by evaluating the effects of a shopping trolley on spinal posture and loading patterns. An exploratory study of kinematic and kinetic changes in walking with and without pushing a shopping trolley in persons with NC symptoms and a comparison with asymptomatic control subjects. A primary care-based musculoskeletal service. Participants (n=8) with NC symptoms who have anecdotally reported symptomatic improvement when walking with a shopping trolley and a control group of asymptomatic persons (n=8). Shopping trolley. Changes in lumbar spinal sagittal posture and ground reaction force. Subjects with NC and asymptomatic controls walked with significantly more flexed spinal posture (increase in flexion, 3.40°; z=3.516; P<.001) and reduced mean ground reaction forces (-6.9% of body weight; z=-3.46; P=.001) when walking with a shopping trolley. However, at the midstance point of the gait cycle, controls showed minimal reliance on the trolley, whereas, people with NC showed continued offloading. Both posture and loading are affected by pushing a shopping trolley; however, patients with NC were found to offload the spine throughout the stance phase of gait, whereas asymptomatic controls did not. Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

A Baltic Sea estuary as a phosphorus source and sink after drastic load reduction: seasonal and long-term mass balances for the Stockholm inner archipelago for 1968-2015

NASA Astrophysics Data System (ADS)

Walve, Jakob; Sandberg, Maria; Larsson, Ulf; Lännergren, Christer

2018-05-01

Internal phosphorus (P) loading from sediments, controlled by hypoxia, is often assumed to hamper the recovery of lakes and coastal areas from eutrophication. In the early 1970s, the external P load to the inner archipelago of Stockholm, Sweden (Baltic Sea), was drastically reduced by improved sewage treatment, but the internal P loading and its controlling factors have been poorly quantified. We use two slightly different four-layer box models to calculate the area's seasonal and annual P balance (input-export) and the internal P exchange with sediments in 1968-2015. For 10-20 years after the main P load reduction, there was a negative P balance, small in comparison to the external load, and probably due to release from legacy sediment P storage. Later, the stabilized, near-neutral P balance indicates no remaining internal loading from legacy P, but P retention is low, despite improved oxygen conditions. Seasonally, sediments are a P sink in spring and a P source in summer and autumn. Most of the deep-water P release from sediments in summer-autumn appears to be derived from the settled spring bloom and is exported to outer areas during winter. Oxygen consumption and P release in the deep water are generally tightly coupled, indicating limited iron control of P release. However, enhanced P release in years of deep-water hypoxia suggests some contribution from redox-sensitive P pools. Increasing deep-water temperatures that stimulate oxygen consumption rates in early summer have counteracted the effect of lowered organic matter sedimentation on oxygen concentrations. Since the P turnover time is short and legacy P small, measures to bind P in Stockholm inner archipelago sediments would primarily accumulate recent P inputs, imported from the Baltic Sea and from Lake Mälaren.

Multiplexer/Demultiplexer Loading Tool (MDMLT)

NASA Technical Reports Server (NTRS)

Brewer, Lenox Allen; Hale, Elizabeth; Martella, Robert; Gyorfi, Ryan

2012-01-01

The purpose of the MDMLT is to improve the reliability and speed of loading multiplexers/demultiplexers (MDMs) in the Software Development and Integration Laboratory (SDIL) by automating the configuration management (CM) of the loads in the MDMs, automating the loading procedure, and providing the capability to load multiple or all MDMs concurrently. This loading may be accomplished in parallel, or single MDMs (remote). The MDMLT is a Web-based tool that is capable of loading the entire International Space Station (ISS) MDM configuration in parallel. It is able to load Flight Equivalent Units (FEUs), enhanced, standard, and prototype MDMs as well as both EEPROM (Electrically Erasable Programmable Read-Only Memory) and SSMMU (Solid State Mass Memory Unit) (MASS Memory). This software has extensive configuration management to track loading history, and the performance improvement means of loading the entire ISS MDM configuration of 49 MDMs in approximately 30 minutes, as opposed to 36 hours, which is what it took previously utilizing the flight method of S-Band uplink. The laptop version recently added to the MDMLT suite allows remote lab loading with the CM of information entered into a common database when it is reconnected to the network. This allows the program to reconfigure the test rigs quickly between shifts, allowing the lab to support a variety of onboard configurations during a single day, based on upcoming or current missions. The MDMLT Computer Software Configuration Item (CSCI) supports a Web-based command and control interface to the user. An interface to the SDIL File Transfer Protocol (FTP) server is supported to import Integrated Flight Loads (IFLs) and Internal Product Release Notes (IPRNs) into the database. An interface to the Monitor and Control System (MCS) is supported to control the power state, and to enable or disable the debug port of the MDMs to be loaded. Two direct interfaces to the MDM are supported: a serial interface (debug port) to receive MDM memory dump data and the calculated checksum, and the Small Computer System Interface (SCSI) to transfer load files to MDMs with hard disks. File transfer from the MDM Loading Tool to EEPROM within the MDM is performed via the MILSTD- 1553 bus, making use of the Real- Time Input/Output Processors (RTIOP) when using the rig-based MDMLT, and via a bus box when using the laptop MDMLT. The bus box is a cost-effective alternative to PC-1553 cards for the laptop. It is noted that this system can be modified and adapted to any avionic laboratory for spacecraft computer loading, ship avionics, or aircraft avionics where multiple configurations and strong configuration management of software/firmware loads are required.

Revisiting control establishments for emerging energy hubs

NASA Astrophysics Data System (ADS)

Nasirian, Vahidreza

Emerging small-scale energy systems, i.e., microgrids and smartgrids, rely on centralized controllers for voltage regulation, load sharing, and economic dispatch. However, the central controller is a single-point-of-failure in such a design as either the controller or attached communication links failure can render the entire system inoperable. This work seeks for alternative distributed control structures to improve system reliability and help to the scalability of the system. A cooperative distributed controller is proposed that uses a noise-resilient voltage estimator and handles global voltage regulation and load sharing across a DC microgrid. Distributed adaptive droop control is also investigated as an alternative solution. A droop-free distributed control is offered to handle voltage/frequency regulation and load sharing in AC systems. This solution does not require frequency measurement and, thus, features a fast frequency regulation. Distributed economic dispatch is also studied, where a distributed protocol is designed that controls generation units to merge their incremental costs into a consensus and, thus, push the entire system to generate with the minimum cost. Experimental verifications and Hardware-in-the-Loop (HIL) simulations are used to study efficacy of the proposed control protocols.

Angular-velocity control approach for stance-control orthoses.

PubMed

Lemaire, Edward D; Goudreau, Louis; Yakimovich, Terris; Kofman, Jonathan

2009-10-01

Currently, stance-control knee orthoses require external control mechanisms to control knee flexion during stance and allow free knee motion during the swing phase of gait. A new angular-velocity control approach that uses a rotary-hydraulic device to resist knee flexion when the knee angular velocity passes a preset threshold is presented. This angular-velocity approach for orthotic stance control is based on the premise that knee-flexion angular velocity during a knee-collapse event, such as a stumble or fall, is greater than that during walking. The new hydraulic knee-flexion control device does not require an external control mechanism to switch from free motion to stance control mode. Functional test results demonstrated that the hydraulic angular-velocity activated knee joint provided free knee motion during walking, engaged upon knee collapse, and supported body weight while the end-user recovered to a safe body position. The joint was tested to 51.6 Nm in single loading tests and passed 200,000 repeated loading cycles with a peak load of 88 Nm per cycle. The hydraulic, angular velocity activation approach has potential to improve safety and security for people with lower extremity weakness or when recovering from joint trauma.

Terminal Duplex Stability and Nucleotide Identity Differentially Control siRNA Loading and Activity in RNA Interference

PubMed Central

Angart, Phillip A.; Carlson, Rebecca J.; Adu-Berchie, Kwasi

2016-01-01

Efficient short interfering RNA (siRNA)-mediated gene silencing requires selection of a sequence that is complementary to the intended target and possesses sequence and structural features that encourage favorable functional interactions with the RNA interference (RNAi) pathway proteins. In this study, we investigated how terminal sequence and structural characteristics of siRNAs contribute to siRNA strand loading and silencing activity and how these characteristics ultimately result in a functionally asymmetric duplex in cultured HeLa cells. Our results reiterate that the most important characteristic in determining siRNA activity is the 5′ terminal nucleotide identity. Our findings further suggest that siRNA loading is controlled principally by the hybridization stability of the 5′ terminus (Nucleotides: 1–2) of each siRNA strand, independent of the opposing terminus. Postloading, RNA-induced silencing complex (RISC)–specific activity was found to be improved by lower hybridization stability in the 5′ terminus (Nucleotides: 3–4) of the loaded siRNA strand and greater hybridization stability toward the 3′ terminus (Nucleotides: 17–18). Concomitantly, specific recognition of the 5′ terminal nucleotide sequence by human Argonaute 2 (Ago2) improves RISC half-life. These findings indicate that careful selection of siRNA sequences can maximize both the loading and the specific activity of the intended guide strand. PMID:27399870

Evaluation of a method for comparing phosphorus loads from barnyards and croplands in Otter Creek Watershed, Wisconsin

USGS Publications Warehouse

Wierl, Judy A.; Giddings, Elise M.P.; Bannerman, Roger T.

1998-01-01

Control of phosphorus from rural nonpoint sources is a major focus of current efforts to improve and protect water resources in Wisconsin and is recommended in almost every priority watershed plan prepared for the State's Nonpoint Source (NFS) Program. Barnyards and crop- lands usually are identified as the primary rural sources of phosphorus. Numerous questions have arisen about which of these two sources to control and about the method currently being used by the NFS program to compare phosphorus loads from barnyards and croplands. To evaluate the method, the U.S. Geological Survey (USGS). in cooperation with the Wisconsin Department of Natural Resources, used phosphorus-load and sediment-load data from streams and phosphorus concentrations in soils from the Otter Creek Watershed (located in the Sheboygan River Basin: fig. 1) in conjunction with two computer-based models. 

Dynamic Tensile Loading Improves the Functional Properties of Mesenchymal Stem Cell-Laden Nanofiber-Based Fibrocartilage

PubMed Central

Baker, Brendon M.; Shah, Roshan P.; Huang, Alice H.

2011-01-01

Fibrocartilaginous tissues such as the meniscus serve critical load-bearing roles, relying on arrays of collagen fibers to resist tensile loads experienced with normal activity. As these structures are frequently injured and possess limited healing capacity, there exists great demand for tissue-engineered replacements. Toward recreating the structural features of these anisotropic tissues in vitro, we employ scaffolds composed of co-aligned nanofibers that direct mesenchymal stem cell (MSC) orientation and the formation of organized extracellular matrix (ECM). Concomitant with ECM synthesis, the mechanical properties of constructs increase with free-swelling culture, but ultimately failed to achieve equivalence with meniscal fibrocartilage. As mechanical forces are essential to the development and maintenance of musculoskeletal tissues, this work examined the effect of cyclic tensile loading on MSC-laden nanofibrous constructs. We hypothesized that loading would modulate the transcriptional behavior of MSCs, spur the deposition of ECM, and lead to enhancements in construct mechanical properties compared to free-swelling controls. Fiber-aligned scaffolds were seeded with MSCs and dynamically loaded daily in tension or maintained as nonloaded controls for 4 weeks. With mechanical stimulation, fibrous gene expression increased, collagen deposition increased, and the tensile modulus increased by 16% relative to controls. These results show that dynamic tensile loading enhances the maturation of MSC-laden aligned nanofibrous constructs, suggesting that recapitulation of the structural and mechanical environment of load-bearing tissues results in increases in functional properties that can be exploited for tissue engineering applications. PMID:21247342

Dynamic tensile loading improves the functional properties of mesenchymal stem cell-laden nanofiber-based fibrocartilage.

PubMed

Baker, Brendon M; Shah, Roshan P; Huang, Alice H; Mauck, Robert L

2011-05-01

Fibrocartilaginous tissues such as the meniscus serve critical load-bearing roles, relying on arrays of collagen fibers to resist tensile loads experienced with normal activity. As these structures are frequently injured and possess limited healing capacity, there exists great demand for tissue-engineered replacements. Toward recreating the structural features of these anisotropic tissues in vitro, we employ scaffolds composed of co-aligned nanofibers that direct mesenchymal stem cell (MSC) orientation and the formation of organized extracellular matrix (ECM). Concomitant with ECM synthesis, the mechanical properties of constructs increase with free-swelling culture, but ultimately failed to achieve equivalence with meniscal fibrocartilage. As mechanical forces are essential to the development and maintenance of musculoskeletal tissues, this work examined the effect of cyclic tensile loading on MSC-laden nanofibrous constructs. We hypothesized that loading would modulate the transcriptional behavior of MSCs, spur the deposition of ECM, and lead to enhancements in construct mechanical properties compared to free-swelling controls. Fiber-aligned scaffolds were seeded with MSCs and dynamically loaded daily in tension or maintained as nonloaded controls for 4 weeks. With mechanical stimulation, fibrous gene expression increased, collagen deposition increased, and the tensile modulus increased by 16% relative to controls. These results show that dynamic tensile loading enhances the maturation of MSC-laden aligned nanofibrous constructs, suggesting that recapitulation of the structural and mechanical environment of load-bearing tissues results in increases in functional properties that can be exploited for tissue engineering applications.

Alkaline peroxide pretreatment of corn stover: effects of biomass, peroxide, and enzyme loading and composition on yields of glucose and xylose

PubMed Central

2011-01-01

Background Pretreatment is a critical step in the conversion of lignocellulose to fermentable sugars. Although many pretreatment processes are currently under investigation, none of them are entirely satisfactory in regard to effectiveness, cost, or environmental impact. The use of hydrogen peroxide at pH 11.5 (alkaline hydrogen peroxide (AHP)) was shown by Gould and coworkers to be an effective pretreatment of grass stovers and other plant materials in the context of animal nutrition and ethanol production. Our earlier experiments indicated that AHP performed well when compared against two other alkaline pretreatments. Here, we explored several key parameters to test the potential of AHP for further improvement relevant to lignocellulosic ethanol production. Results The effects of biomass loading, hydrogen peroxide loading, residence time, and pH control were tested in combination with subsequent digestion with a commercial enzyme preparation, optimized mixtures of four commercial enzymes, or optimized synthetic mixtures of pure enzymes. AHP pretreatment was performed at room temperature (23°C) and atmospheric pressure, and after AHP pretreatment the biomass was neutralized with HCl but not washed before enzyme digestion. Standard enzyme digestion conditions were 0.2% glucan loading, 15 mg protein/g glucan, and 48 h digestion at 50°C. Higher pretreatment biomass loadings (10% to 20%) gave higher monomeric glucose (Glc) and xylose (Xyl) yields than the 2% loading used in earlier studies. An H2O2 loading of 0.25 g/g biomass was almost as effective as 0.5 g/g, but 0.125 g/g was significantly less effective. Optimized mixtures of four commercial enzymes substantially increased post-AHP-pretreatment enzymatic hydrolysis yields at all H2O2 concentrations compared to any single commercial enzyme. At a pretreatment biomass loading of 10% and an H2O2 loading of 0.5 g/g biomass, an optimized commercial mixture at total protein loadings of 8 or 15 mg/g glucan gave monomeric Glc yields of 83% or 95%, respectively. Yields of Glc and Xyl after pretreatment at a low hydrogen peroxide loading (0.125 g H2O2/g biomass) could be improved by extending the pretreatment residence time to 48 h and readjusting the pH to 11.5 every 6 h during the pretreatment. A Glc yield of 77% was obtained using a pretreatment of 15% biomass loading, 0.125 g H2O2/g biomass, and 48 h with pH adjustment, followed by digestion with an optimized commercial enzyme mixture at an enzyme loading of 15 mg protein/g glucan. Conclusions Alkaline peroxide is an effective pretreatment for corn stover. Particular advantages are the use of reagents with low environmental impact and avoidance of special reaction chambers. Reasonable yields of monomeric Glc can be obtained at an H2O2 concentration one-quarter of that used in previous AHP research. Additional improvements in the AHP process, such as peroxide stabilization, peroxide recycling, and improved pH control, could lead to further improvements in AHP pretreatment. PMID:21658263

Delayed administration of recombinant human parathyroid hormone improves early biomechanical strength in a rat rotator cuff repair model.

PubMed

Duchman, Kyle R; Goetz, Jessica E; Uribe, Bastian U; Amendola, Andrew M; Barber, Joshua A; Malandra, Allison E; Fredericks, Douglas C; Hettrich, Carolyn M

2016-08-01

Despite advances in intraoperative techniques, rotator cuff repairs frequently do not heal. Recombinant human parathyroid hormone (rhPTH) has been shown to improve healing at the tendon-to-bone interface in an established acute rat rotator cuff repair model. We hypothesized that administration of rhPTH beginning on postoperative day 7 would result in improved early load to failure after acute rotator cuff repair in an established rat model. Acute rotator cuff repairs were performed in 108 male Sprague-Dawley rats. Fifty-four rats received daily injections of rhPTH beginning on postoperative day 7 until euthanasia or a maximum of 12 weeks postoperatively. The remaining 54 rats received no injections and served as the control group. Animals were euthanized at 2 and 16 weeks postoperatively and evaluated by gross inspection, biomechanical testing, and histologic analysis. At 2 weeks postoperatively, rats treated with rhPTH demonstrated significantly higher load to failure than controls (10.9 vs. 5.2 N; P = .003). No difference in load to failure was found between the 2 groups at 16 weeks postoperatively, although control repairs more frequently failed at the tendon-to-bone interface (45.5% vs. 22.7%; P = .111). Blood vessel density appeared equivalent between the 2 groups at both time points, but increased intracellular and extracellular vascular endothelial growth factor expression was noted in the rhPTH-treated group at 2 weeks. Delayed daily administration of rhPTH resulted in increased early load to failure and equivalent blood vessel density in an acute rotator cuff repair model. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

DIESEL ENGINE EFFICIENCY AND EMISSIONS IMPROVEMENT VIA PISTON TEMPERATURE CONTROL - PHASE I

EPA Science Inventory

Modeling and sliding mode predictive control of the ultra-supercritical boiler-turbine system with uncertainties and input constraints.

PubMed

Tian, Zhen; Yuan, Jingqi; Zhang, Xiang; Kong, Lei; Wang, Jingcheng

2018-05-01

The coordinated control system (CCS) serves as an important role in load regulation, efficiency optimization and pollutant reduction for coal-fired power plants. The CCS faces with tough challenges, such as the wide-range load variation, various uncertainties and constraints. This paper aims to improve the load tacking ability and robustness for boiler-turbine units under wide-range operation. To capture the key dynamics of the ultra-supercritical boiler-turbine system, a nonlinear control-oriented model is developed based on mechanism analysis and model reduction techniques, which is validated with the history operation data of a real 1000 MW unit. To simultaneously address the issues of uncertainties and input constraints, a discrete-time sliding mode predictive controller (SMPC) is designed with the dual-mode control law. Moreover, the input-to-state stability and robustness of the closed-loop system are proved. Simulation results are presented to illustrate the effectiveness of the proposed control scheme, which achieves good tracking performance, disturbance rejection ability and compatibility to input constraints. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Aptamer-based liposomes improve specific drug loading and release.

PubMed

Plourde, Kevin; Derbali, Rabeb Mouna; Desrosiers, Arnaud; Dubath, Céline; Vallée-Bélisle, Alexis; Leblond, Jeanne

2017-04-10

Aptamer technology has shown much promise in cancer therapeutics for its targeting abilities. However, its potential to improve drug loading and release from nanocarriers has not been thoroughly explored. In this study, we employed drug-binding aptamers to actively load drugs into liposomes. We designed a series of DNA aptamer sequences specific to doxorubicin, displaying multiple binding sites and various binding affinities. The binding ability of aptamers was preserved when incorporated into cationic liposomes, binding up to 15equivalents of doxorubicin per aptamer, therefore drawing the drug into liposomes. Optimization of the charge and drug/aptamer ratios resulted in ≥80% encapsulation efficiency of doxorubicin, ten times higher than classical passively-encapsulating liposomal formulations and similar to a pH-gradient active loading strategy. In addition, kinetic release profiles and cytotoxicity assay on HeLa cells demonstrated that the release and therapeutic efficacy of liposomal doxorubicin could be controlled by the aptamer's structure. Our results suggest that the aptamer exhibiting a specific intermediate affinity is the best suited to achieve high drug loading while maintaining efficient drug release and therapeutic activity. This strategy was successfully applied to tobramycin, a hydrophilic drug suffering from low encapsulation into liposomes, where its loading was improved six-fold using aptamers. Overall, we demonstrate that aptamers could act, in addition to their targeting properties, as multifunctional excipients for liposomal formulations. Copyright © 2017 Elsevier B.V. All rights reserved.

Transient performance analysis of the master cylinder hydraulic system of a 6.3 MN fineblanking press

NASA Astrophysics Data System (ADS)

Yi, Guodong; Li, Jin

2018-03-01

The master cylinder hydraulic system is the core component of the fineblanking press that seriously affects the machine performance. A key issue in the design of the master cylinder hydraulic system is dealing with the heavy shock loads in the fineblanking process. In this paper, an equivalent model of the master cylinder hydraulic system is established based on typical process parameters for practical fineblanking; then, the response characteristics of the master cylinder slider to the step changes in the load and control current are analyzed, and lastly, control strategies for the proportional valve are studied based on the impact of the control parameters on the kinetic stability of the slider. The results show that the kinetic stability of the slider is significantly affected by the step change of the control current, while it is slightly affected by the step change of the system load, which can be improved by adjusting the flow rate and opening time of the proportional valve.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelekis, Alexios, E-mail: akelekis@med.uoa.gr; Filippiadis, Dimitrios K., E-mail: dfilippiadis@yahoo.gr; Vergadis, Chrysovalantis, E-mail: valvergadis@yahoo.gr

PurposeThrough a prospective comparison of patients with vertebral fractures and normal population, we illustrate effect of percutaneous vertebroplasty (PV) upon projection of load distribution changes.MethodsVertebroplasty group (36 symptomatic patients with osteoporotic vertebral fractures) was evaluated on an electronic baropodometer registering projection of weight bearing areas on feet. Load distribution between right and left foot (including rear-front of the same foot) during standing and walking was recorded and compared before (group V1) and the day after (group V2) PV. Control group (30 healthy asymptomatic volunteers-no surgery record) were evaluated on the same baropodometer.ResultsMean value of load distribution difference between rear-front ofmore » the same foot was 9.45 ± 6.79 % (54.72–45.28 %) upon standing and 14.76 ± 7.09 % (57.38–42.62 %) upon walking in the control group. Respective load distribution values before PV were 16.52 ± 11.23 and 30.91 ± 19.26 % and after PV were 10.08 ± 6.26 and 14.25 ± 7.68 % upon standing and walking respectively. Mean value of load distribution variation between the two feet was 6.36 and 14.6 % before and 4.62 and 10.4 % after PV upon standing and walking respectively. Comparison of load distribution variation (group V1–V2, group V1-control group) is statistically significant. Comparison of load distribution variation (group V2-control group) is not statistically significant. Comparison of load distribution variation among the two feet is statistically significant during walking but not statistically significant during standing.ConclusionsThere is a statistically significant difference when comparing load distribution variation prior vertebroplasty and that of normal population. After vertebroplasty, this difference normalizes in a statistically significant way. PV is efficient on equilibrium-load distribution improvement as well.« less

Improving health outcomes for youth living with the human immunodeficiency virus: a multisite randomized trial of a motivational intervention targeting multiple risk behaviors.

PubMed

Naar-King, Sylvie; Parsons, Jeffrey T; Murphy, Debra A; Chen, Xinguang; Harris, D Robert; Belzer, Marvin E

2009-12-01

To determine if Healthy Choices, a motivational interviewing intervention targeting multiple risk behaviors, improved human immunodeficiency virus (HIV) viral load. A randomized, 2-group repeated measures design with analysis of data from baseline and 6- and 9-month follow-up collected from 2005 to 2007. Five US adolescent medicine HIV clinics. A convenience sample with at least 1 of 3 risk behaviors (nonadherence to HIV medications, substance abuse, and unprotected sex) was enrolled. The sample was aged 16 to 24 years and primarily African American. Of the 205 enrolled, 19 did not complete baseline data collections, for a final sample size of 186. Young people living with HIV were randomized to the intervention plus specialty care (n = 94) or specialty care alone (n = 92). The 3- and 6-month follow-up rates, respectively, were 86% and 82% for the intervention group and 81% and 73% for controls. Intervention Healthy Choices was a 4-session individual clinic-based motivational interviewing intervention delivered during a 10-week period. Motivational interviewing is a method of communication designed to elicit and reinforce intrinsic motivation for change. Outcome Measure Plasma viral load. Youth randomized to Healthy Choices showed a significant decline in viral load at 6 months postintervention compared with youth in the control condition (beta = -0.36, t = -2.15, P = .03), with those prescribed antiretroviral medications showing the lowest viral loads. Differences were no longer significant at 9 months. A motivational interviewing intervention targeting multiple risk behaviors resulted in short-term improvements in viral load for youth living with HIV. Trial Registration clinicaltrials.gov Identifier: NCT00103532.

Impacts of climate change on TN load and its control in a River Basin with complex pollution sources.

PubMed

Yang, Xiaoying; Warren, Rachel; He, Yi; Ye, Jinyin; Li, Qiaoling; Wang, Guoqing

2018-02-15

It is increasingly recognized that climate change could affect the quality of water through complex natural and anthropogenic mechanisms. Previous studies on climate change and water quality have mostly focused on assessing its impact on pollutant loads from agricultural runoff. A sub-daily SWAT model was developed to simulate the discharge, transport, and transformation of nitrogen from all known anthropogenic sources including industries, municipal sewage treatment plants, concentrated and scattered feedlot operations, rural households, and crop production in the Upper Huai River Basin. This is a highly polluted basin with total nitrogen (TN) concentrations frequently exceeding Class V of the Chinese Surface Water Quality Standard (GB3838-2002). Climate change projections produced by 16 Global Circulation Models (GCMs) under the RCP 4.5 and RCP 8.5 scenarios in the mid (2040-2060) and late (2070-2090) century were used to drive the SWAT model to evaluate the impacts of climate change on both the TN loads and the effectiveness of three water pollution control measures (reducing fertilizer use, constructing vegetative filter strips, and improving septic tank performance) in the basin. SWAT simulation results have indicated that climate change is likely to cause an increase in both monthly average and extreme TN loads in February, May, and November. The projected impact of climate change on TN loads in August is more varied between GCMs. In addition, climate change is projected to have a negative impact on the effectiveness of septic tanks in reducing TN loads, while its impacts on the other two measures are more uncertain. Despite the uncertainty, reducing fertilizer use remains the most effective measure for reducing TN loads under different climate change scenarios. Meanwhile, improving septic tank performance is relatively more effective in reducing annual TN loads, while constructing vegetative filter strips is more effective in reducing annual maximum monthly TN loads. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of the Combined Application of Neuromuscular Electrical Stimulation and Volitional Contractions on Thigh Muscle Strength, Knee Pain and Physical Performance in Women at Risk for Knee Osteoarthritis: A Randomized Controlled Trial.

PubMed

Rabe, Kaitlin G; Matsuse, Hiroo; Jackson, Anthony; Segal, Neil A

2018-05-28

Knee osteoarthritis (OA) is a leading cause of disability that is associated with quadriceps weakness. However, strengthening in people with or with risk factors for knee OA can be poorly tolerated. To assess the efficacy of a twelve-week low-load exercise program, using a hybrid training system (HTS) that utilizes the combination of neuromuscular electrical stimulation and volitional contractions, for improving thigh muscle strength, knee pain and physical performance in women with or with risk factors for knee OA. Randomized, single-blind, controlled trial SETTING: Exercise training laboratory PARTICIPANTS: Forty-two women, age 44-85 years, with risk factors for knee OA INTERVENTIONS: Participants randomized to 12 weeks of biweekly low-load resistance training either with HTS or on an isokinetic dynamometer (control). Maximum isokinetic knee extensor torque. Secondary measures included: maximum isokinetic knee flexor torque, knee pain (KOOS), and timed 20-meter walk and chair-stand tests. HTS and control both resulted in muscle strengthening, reduced knee pain and improved physical performance. HTS group quadriceps and hamstring strength increased by 0.06±0.04 Nm/kg (p>.05) and 0.05±0.02 Nm/kg (p=.02), respectively. Control group quadriceps and hamstring strength increased by 0.03±0.04 Nm/kg (p>.05) and 0.06±0.02 Nm/kg (p=.009), respectively. Knee pain improved by 11.9±11.5 points (p<.001) for the HTS group and 14.1±15.4 points (p=.001) for the control group. 20-meter walk time decreased by 1.60±2.04 seconds (p=.005) and 0.95±1.2 seconds (p=.004), and chair stand time decreased by 4.8±10.0 seconds (p>.05) and 1.9±4.7 seconds (p>.05) in the HTS and control groups, respectively. These results did not differ statistically between HTS and control groups. These results suggest HTS is effective for improving pain and physical performance in women with risk factors for knee OA. However, HTS does not appear to be superior to low-load resistance training for improving muscle strength, pain or physical function. Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Method to Increase Performance of Foil Bearings Through Passive Thermal Management

NASA Technical Reports Server (NTRS)

Bruckner, Robert

2013-01-01

This invention is a new approach to designing foil bearings to increase their load capacity and improve their reliability through passive thermal management. In the present case, the bearing is designed in such a way as to prevent the carryover of lubricant from the exit of one sector to the inlet of the ensuing sector of the foil bearing. When such passive thermal management techniques are used, bearing load capacity is improved by multiples, and reliability is enhanced when compared to current foil bearings. This concept has recently been tested and validated, and shows that load capacity performance of foil bearings can be improved by a factor of two at relatively low speeds with potentially greater relative improvements at higher speeds. Such improvements in performance with respect to speed are typical of foil bearings. Additionally, operation of these newly conceived bearings shows much more reliability and repeatable performance. This trait can be exploited in machine design to enhance safety, reliability, and overall performance. Finally, lower frictional torque has been demonstrated when operating at lower (non-load capacity) loads, thus providing another improvement above the current state of the art. The objective of the invention is to incorporate features into a foil bearing that both enhance passive thermal management and temperature control, while at the same time improve the hydrodynamic (load capacity) performance of the foil bearing. Foil bearings are unique antifriction devices that can utilize the working fluid of a machine as a lubricant (typically air for turbines and motors, liquids for pumps), and as a coolant to remove excess energy due to frictional heating. The current state of the art of foil bearings utilizes forced cooling of the bearing and shaft, which represents poor efficiency and poor reliability. This invention embodies features that utilize the bearing geometry in such a manner as to both support load and provide an inherent and passive cooling mechanism. This cooling mechanism functions in such a way as to prevent used (higher temperature) lubricant from being carried over from the exit of one sector into the entry of the next sector of the foil bearing. The disclosed innovation is an improved foil bearing design that reduces or eliminates the need for force cooling of the bearing, while at the same time improving the load capacity of the bearing by at least a factor of two. These improvements are due to the elimination of lubricant carryover from the trailing edge of one sector into the leading edge of the next, and the mixing of used lubricant with the surrounding ambient fluid.

Fuzzy-PI-based centralised control of semi-isolated FP-SEPIC/ZETA BDC in a PV/battery hybrid system

NASA Astrophysics Data System (ADS)

Mahendran, Venmathi; Ramabadran, Ramaprabha

2016-11-01

Multiport converters with centralised controller have been most commonly used in stand-alone photovoltaic (PV)/battery hybrid system to supply the load smoothly without any disturbances. This study presents the performance analysis of four-port SEPIC/ZETA bidirectional converter (FP-SEPIC/ZETA BDC) using various types of centralised control schemes like Fuzzy tuned proportional integral controller (Fuzzy-PI), fuzzy logic controller (FLC) and conventional proportional integral (PI) controller. The proposed FP-SEPIC/ZETA BDC with various control strategy is derived for simultaneous power management of a PV source using distributed maximum power point tracking (DMPPT) algorithm, a rechargeable battery, and a load by means of centralised controller. The steady state and the dynamic response of the FP-SEPIC/ZETA BDC are analysed using three different types of controllers under line and load regulation. The Fuzzy-PI-based control scheme improves the dynamic response of the system when compared with the FLC and the conventional PI controller. The power balance between the ports is achieved by pseudorandom carrier modulation scheme. The response of the FP-SEPIC/ZETA BDC is also validated experimentally using hardware prototype model of 500 W system. The effectiveness of the control strategy is validated using simulation and experimental results.

The effects of acute stress and perceptual load on distractor interference.

PubMed

Sato, Hirotsune; Takenaka, Ippei; Kawahara, Jun I

2012-01-01

Selective attention can be improved under conditions in which a high perceptual load is assumed to exhaust cognitive resources, leaving scarce resources for distractor processing. The present study examined whether perceptual load and acute stress share common attentional resources by manipulating perceptual and stress loads. Participants identified a target within an array of nontargets that were flanked by compatible or incompatible distractors. Attentional selectivity was measured by longer reaction times in response to the incompatible than to the compatible distractors. Participants in the stress group participated in a speech test that increased anxiety and threatened self-esteem. The effect of perceptual load interacted with the stress manipulation in that participants in the control group demonstrated an interference effect under the low perceptual load condition, whereas such interference disappeared under the high perceptual load condition. Importantly, the stress group showed virtually no interference under the low perceptual load condition, whereas substantial interference occurred under the high perceptual load condition. These results suggest that perceptual and stress related demands consume the same attentional resources.

A coordinated MIMO control design for a power plant using improved sliding mode controller.

PubMed

Ataei, Mohammad; Hooshmand, Rahmat-Allah; Samani, Siavash Golmohammadi

2014-03-01

For the participation of the steam power plants in regulating the network frequency, boilers and turbines should be co-ordinately controlled in addition to the base load productions. Lack of coordinated control over boiler-turbine may lead to instability; oscillation in producing power and boiler parameters; reduction in the reliability of the unit; and inflicting thermodynamic tension on devices. This paper proposes a boiler-turbine coordinated multivariable control system based on improved sliding mode controller (ISMC). The system controls two main boiler-turbine parameters i.e., the turbine revolution and superheated steam pressure of the boiler output. For this purpose, a comprehensive model of the system including complete and exact description of the subsystems is extracted. The parameters of this model are determined according to our case study that is the 320MW unit of Islam-Abad power plant in Isfahan/Iran. The ISMC method is simulated on the power plant and its performance is compared with the related real PI (proportional-integral) controllers which have been used in this unit. The simulation results show the capability of the proposed controller system in controlling local network frequency and superheated steam pressure in the presence of load variations and disturbances of boiler. © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Application of attachment modes in the control of large space structures

NASA Technical Reports Server (NTRS)

Craig, Roy R., Jr.

1989-01-01

Various ways are examined to obtain reduced order mathematical models of structures for use in dynamic response analyses and in controller design studies. Attachment modes are deflection shapes of a structure subjected to specified unit load distributions. Attachment modes are frequently employed to supplement free-interface normal modes to improve the modeling of components (structures) employed in component mode synthesis analyses. Deflection shapes of structures subjected to generalized loads of some specified distribution and of unit magnitude can also be considered to be attachment modes. Several papers which were written under this contract are summarized herein.

Double loaded self-decomposable SiO2 nanoparticles for sustained drug release

NASA Astrophysics Data System (ADS)

Zhao, Saisai; Zhang, Silu; Ma, Jiang; Fan, Li; Yin, Chun; Lin, Ge; Li, Quan

2015-10-01

Sustained drug release for a long duration is a desired feature of modern drugs. Using double-loaded self-decomposable SiO2 nanoparticles, we demonstrated sustained drug release in a controllable manner. The double loading of the drugs was achieved using two different mechanisms--the first one via a co-growth mechanism, and the second one by absorption. A two-phase sustained drug release was firstly revealed in an in vitro system, and then further demonstrated in mice. After a single intravenous injection, the drug was controllably released from the nanoparticles into blood circulation with a Tmax of about 8 h, afterwards a long lasting release pattern was achieved to maintain drug systemic exposure with a plasma elimination half-life of approximately 28 h. We disclosed that the absorbed drug molecules contributed to the initial fast release for quickly reaching the therapeutic level with relatively higher plasma concentrations, while the ``grown-in'' drugs were responsible for maintaining the therapeutic level via the later controlled slow and sustained release. The present nanoparticle carrier drug configuration and the loading/maintenance release mechanisms provide a promising platform that ensures a prolonged therapeutic effect by controlling drug concentrations within the therapeutic window--a sustained drug delivery system with a great impact on improving the management of chronic diseases.Sustained drug release for a long duration is a desired feature of modern drugs. Using double-loaded self-decomposable SiO2 nanoparticles, we demonstrated sustained drug release in a controllable manner. The double loading of the drugs was achieved using two different mechanisms--the first one via a co-growth mechanism, and the second one by absorption. A two-phase sustained drug release was firstly revealed in an in vitro system, and then further demonstrated in mice. After a single intravenous injection, the drug was controllably released from the nanoparticles into blood circulation with a Tmax of about 8 h, afterwards a long lasting release pattern was achieved to maintain drug systemic exposure with a plasma elimination half-life of approximately 28 h. We disclosed that the absorbed drug molecules contributed to the initial fast release for quickly reaching the therapeutic level with relatively higher plasma concentrations, while the ``grown-in'' drugs were responsible for maintaining the therapeutic level via the later controlled slow and sustained release. The present nanoparticle carrier drug configuration and the loading/maintenance release mechanisms provide a promising platform that ensures a prolonged therapeutic effect by controlling drug concentrations within the therapeutic window--a sustained drug delivery system with a great impact on improving the management of chronic diseases. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03029c

E-beam high voltage switching power supply

DOEpatents

Shimer, D.W.; Lange, A.C.

1996-10-15

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 figs.

E-beam high voltage switching power supply

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1996-01-01

A high-power power supply produces a controllable, constant high voltage put under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

A Review of Distributed Control Techniques for Power Quality Improvement in Micro-grids

NASA Astrophysics Data System (ADS)

Zeeshan, Hafiz Muhammad Ali; Nisar, Fatima; Hassan, Ahmad

2017-05-01

Micro-grid is typically visualized as a small scale local power supply network dependent on distributed energy resources (DERs) that can operate simultaneously with grid as well as in standalone manner. The distributed generator of a micro-grid system is usually a converter-inverter type topology acting as a non-linear load, and injecting harmonics into the distribution feeder. Hence, the negative effects on power quality by the usage of distributed generation sources and components are clearly witnessed. In this paper, a review of distributed control approaches for power quality improvement is presented which encompasses harmonic compensation, loss mitigation and optimum power sharing in multi-source-load distributed power network. The decentralized subsystems for harmonic compensation and active-reactive power sharing accuracy have been analysed in detail. Results have been validated to be consistent with IEEE standards.

Control and Optimization of Electric Ship Propulsion Systems with Hybrid Energy Storage

NASA Astrophysics Data System (ADS)

Hou, Jun

Electric ships experience large propulsion-load fluctuations on their drive shaft due to encountered waves and the rotational motion of the propeller, affecting the reliability of the shipboard power network and causing wear and tear. This dissertation explores new solutions to address these fluctuations by integrating a hybrid energy storage system (HESS) and developing energy management strategies (EMS). Advanced electric propulsion drive concepts are developed to improve energy efficiency, performance and system reliability by integrating HESS, developing advanced control solutions and system integration strategies, and creating tools (including models and testbed) for design and optimization of hybrid electric drive systems. A ship dynamics model which captures the underlying physical behavior of the electric ship propulsion system is developed to support control development and system optimization. To evaluate the effectiveness of the proposed control approaches, a state-of-the-art testbed has been constructed which includes a system controller, Li-Ion battery and ultra-capacitor (UC) modules, a high-speed flywheel, electric motors with their power electronic drives, DC/DC converters, and rectifiers. The feasibility and effectiveness of HESS are investigated and analyzed. Two different HESS configurations, namely battery/UC (B/UC) and battery/flywheel (B/FW), are studied and analyzed to provide insights into the advantages and limitations of each configuration. Battery usage, loss analysis, and sensitivity to battery aging are also analyzed for each configuration. In order to enable real-time application and achieve desired performance, a model predictive control (MPC) approach is developed, where a state of charge (SOC) reference of flywheel for B/FW or UC for B/UC is used to address the limitations imposed by short predictive horizons, because the benefits of flywheel and UC working around high-efficiency range are ignored by short predictive horizons. Given the multi-frequency characteristics of load fluctuations, a filter-based control strategy is developed to illustrate the importance of the coordination within the HESS. Without proper control strategies, the HESS solution could be worse than a single energy storage system solution. The proposed HESS, when introduced into an existing shipboard electrical propulsion system, will interact with the power generation systems. A model-based analysis is performed to evaluate the interactions of the multiple power sources when a hybrid energy storage system is introduced. The study has revealed undesirable interactions when the controls are not coordinated properly, and leads to the conclusion that a proper EMS is needed. Knowledge of the propulsion-load torque is essential for the proposed system-level EMS, but this load torque is immeasurable in most marine applications. To address this issue, a model-based approach is developed so that load torque estimation and prediction can be incorporated into the MPC. In order to evaluate the effectiveness of the proposed approach, an input observer with linear prediction is developed as an alternative approach to obtain the load estimation and prediction. Comparative studies are performed to illustrate the importance of load torque estimation and prediction, and demonstrate the effectiveness of the proposed approach in terms of improved efficiency, enhanced reliability, and reduced wear and tear. Finally, the real-time MPC algorithm has been implemented on a physical testbed. Three different efforts have been made to enable real-time implementation: a specially tailored problem formulation, an efficient optimization algorithm and a multi-core hardware implementation. Compared to the filter-based strategy, the proposed real-time MPC achieves superior performance, in terms of the enhanced system reliability, improved HESS efficiency, and extended battery life.

Optimization of vitamins A and D3 loading in re-assembled casein micelles and effect of loading on stability of vitamin D3 during storage.

PubMed

Loewen, Anisa; Chan, Benny; Li-Chan, Eunice C Y

2018-02-01

The objectives of this study were to apply response surface methodology to optimize fat-soluble vitamin loading in re-assembled casein micelles, and to evaluate vitamin D stability of dry formulations during ambient or accelerated storage and in fortified fluid skim milk stored under refrigeration. Optimal loading of vitamin A (1.46-1.48mg/100mgcasein) was found at 9.7mM phosphate, 5.5mM citrate and 30.0mM calcium, while optimal loading of vitamin D (1.38-1.46mg/100mg casein) was found at 4.9mM phosphate, 4.0mM citrate and 26.1mM calcium. In general, more vitamin D was retained in vitamin D-re-assembled casein micelles than control powders during storage, while vitamin D loss was not different for vitamin D-re-assembled casein micelles and control fortified milks after 21days of refrigerated storage with light exposure. In conclusion, re-assembled casein micelles with high loading efficiency show promise for improving vitamin D stability during dry storage. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Centralized and Decentralized Control for Demand Response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Shuai; Samaan, Nader A.; Diao, Ruisheng

2011-04-29

Demand response has been recognized as an essential element of the smart grid. Frequency response, regulation and contingency reserve functions performed traditionally by generation resources are now starting to involve demand side resources. Additional benefits from demand response include peak reduction and load shifting, which will defer new infrastructure investment and improve generator operation efficiency. Technical approaches designed to realize these functionalities can be categorized into centralized control and decentralized control, depending on where the response decision is made. This paper discusses these two control philosophies and compares their relative advantages and disadvantages in terms of delay time, predictability, complexity,more » and reliability. A distribution system model with detailed household loads and controls is built to demonstrate the characteristics of the two approaches. The conclusion is that the promptness and reliability of decentralized control should be combined with the predictability and simplicity of centralized control to achieve the best performance of the smart grid.« less

Effect of finite element model loading condition on fracture risk assessment in men and women: the AGES-Reykjavik study.

PubMed

Keyak, J H; Sigurdsson, S; Karlsdottir, G S; Oskarsdottir, D; Sigmarsdottir, A; Kornak, J; Harris, T B; Sigurdsson, G; Jonsson, B Y; Siggeirsdottir, K; Eiriksdottir, G; Gudnason, V; Lang, T F

2013-11-01

Proximal femoral (hip) strength computed by subject-specific CT scan-based finite element (FE) models has been explored as an improved measure for identifying subjects at risk of hip fracture. However, to our knowledge, no published study has reported the effect of loading condition on the association between incident hip fracture and hip strength. In the present study, we performed a nested age- and sex-matched case-control study in the Age Gene/Environment Susceptibility (AGES) Reykjavik cohort. Baseline (pre-fracture) quantitative CT (QCT) scans of 5500 older male and female subjects were obtained. During 4-7years follow-up, 51 men and 77 women sustained hip fractures. Ninety-seven men and 152 women were randomly selected as controls from a pool of age- and sex-matched subjects. From the QCT data, FE models employing nonlinear material properties computed FE-strength of the left hip of each subject in loading from a fall onto the posterolateral (FPL), posterior (FP) and lateral (FL) aspects of the greater trochanter (patent pending). For comparison, FE strength in stance loading (FStance) and total femur areal bone mineral density (aBMD) were also computed. For all loading conditions, the reductions in strength associated with fracture in men were more than twice those in women (p≤0.01). For fall loading specifically, posterolateral loading in men and posterior loading in women were most strongly associated with incident hip fracture. After adjusting for aBMD, the association between FP and fracture in women fell short of statistical significance (p=0.08), indicating that FE strength provides little advantage over aBMD for identifying female hip fracture subjects. However, in men, after controlling for aBMD, FPL was 424N (11%) less in subjects with fractures than in controls (p=0.003). Thus, in men, FE models of posterolateral loading include information about incident hip fracture beyond that in aBMD. © 2013.

Relationship between medication synchronization and antiretroviral adherence.

PubMed

Ghassemi, Emily; Smith, Jennifer; Owens, Laura; Herring, Charles; Holland, Melissa

2018-06-12

To compare antiretroviral adherence (measured as the proportion of days covered [PDC]) and change in viral load in insured, HIV-infected, adult outpatients enrolled and not enrolled in a medication synchronization program. This was a multicenter, retrospective, pilot cohort study. Fifty-eight insured, HIV-infected, outpatients at least 18 years of age receiving antiretroviral therapy (ART) for at least 3 months as of August 2015 were included. PDC, viral load, PDC dichotomized into adherent or nonadherent, and viral load dichotomized into detectable or undetectable were collected for each patient. Study data were compared in those with (enrolled) and without (not enrolled or control) medication synchronization. The study end points were analyzed between the 2 groups retrospectively after 3 months. PDC in patients undergoing medication synchronization was significantly higher than in control patients: mean ± SD 96 ± 9% versus 71 ± 27%, respectively (P < 0.0001). The medication synchronization group was also more likely to be adherent to ART than the control group (odds ratio 10.67, 95% confidence interval 2.63-43.31). In the medication synchronization group, 75.9% of patients had an undetectable baseline viral load, and 83.3% had an undetectable viral load at study completion. In the control group, 62.1% and 64.7% had an undetectable viral load at baseline and completion, respectively. No statistically significant change in viral load was observed between groups (P = 0.34). In insured, HIV-infected, adult outpatients, implementation of a medication synchronization program was associated with improved ART adherence. Future studies are needed to better assess the impact of medication synchronization on clinical outcomes. Copyright © 2018 American Pharmacists Association®. All rights reserved.

Estimated dissolved-solids loads and trends at selected streams in and near the Uinta Basin, Utah, Water Years 1989–2013

USGS Publications Warehouse

Thiros, Susan A.

2017-03-23

The U.S. Geological Survey (USGS), in cooperation with the Colorado River Basin Salinity Control Forum, studied trends in dissolved-solids loads at selected sites in and near the Uinta Basin, Utah. The Uinta Basin study area includes the Duchesne River Basin and the Middle Green River Basin in Utah from below Flaming Gorge Reservoir to the town of Green River.Annual dissolved-solids loads for water years (WY) 1989 through 2013 were estimated for 16 gaging stations in the study area using streamflow and water-quality data from the USGS National Water Information System database. Eight gaging stations that monitored catchments with limited or no agricultural land use (natural subbasins) were used to assess loads from natural sources. Four gaging stations that monitored catchments with agricultural land in the Duchesne River Basin were used to assess loads from agricultural sources. Four other gaging stations were included in the dissolved-solids load and trend analysis to help assess the effects of agricultural areas that drain to the Green River in the Uinta Basin, but outside of the Duchesne River Basin.Estimated mean annual dissolved-solids loads for WY 1989–2013 ranged from 1,520 tons at Lake Fork River above Moon Lake, near Mountain Home, Utah (UT), to 1,760,000 tons at Green River near Green River, UT. The flow-normalized loads at gaging stations upstream of agricultural activities showed no trend or a relatively small change. The largest net change in modeled flow-normalized load was -352,000 tons (a 17.8-percent decrease) at Green River near Green River, UT.Annual streamflow and modeled dissolved-solids loads at the gaging stations were balanced between upstream and downstream sites to determine how much water and dissolved solids were transported to the Duchesne River and a section of the Green River, and how much was picked up in each drainage area. Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites show that Green River near Jensen, UT, accounts for 64 percent of the load in the river at Green River, UT, while the Duchesne River and White River contribute 10 and 13 percent, respectively.Annual streamflow and modeled dissolved-solids loads at the gaging stations were balanced between upstream and downstream sites to determine how much water and dissolved solids were transported to the Duchesne River and a section of the Green River, and how much was picked up in each drainage area. Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites show that Green River near Jensen, UT, accounts for 64 percent of the load in the river at Green River, UT, while the Duchesne River and White River contribute 10 and 13 percent, respectively.The flow-normalized dissolved-solids loads estimated at Duchesne River near Randlett, UT, and White River near Watson, UT, decreased by 68,000 and 55,300 tons, or 27.8 and 20.8 percent respectively, when comparing 1989 to 2013. The drainage basins for both rivers have undergone salinity-control projects since the early 1980s to reduce the dissolved-solids load entering the Colorado River. Approximately 19 percent of the net change in flow-normalized load at Green River at Green River, UT, is from changes in load modeled at Duchesne River near Randlett, UT, and 16 percent from changes in load modeled at White River near Watson, UT. The net change in flow-normalized load estimated at Green River near Greendale, UT, for WY 1989–2013 accounts for about 45 percent of the net change estimated at Green River at Green River, UT.Mass-balance calculations of WY 1989–2013 mean annual dissolved-solids loads at the studied sites in the Duchesne River Basin show that 75,400 tons or 44 percent of the load at the Duchesne River near Randlett, UT, gaging station was not accounted for at any of the upstream gages. Most of this unmonitored load is derived from tributary inflow, groundwater discharge, unconsumed irrigation water, and irrigation tail water.A mass balance of WY 1989–2013 flow-normalized loads estimated at sites in the Duchesne River Basin indicates that the flow-normalized load of unmonitored inflow to the Duchesne River between the Myton and Randlett gaging stations decreased by 38 percent. The total net decrease in flow-normalized load calculated for unmonitored inflow in the drainage basin accounts for 94 percent of the decrease in WY 1989–2013 flow-normalized load modeled at the Duchesne River near Randlett, UT, gaging station. Irrigation improvements in the drainage basin have likely contributed to the decrease in flow-normalized load.Reductions in dissolved-solids load estimated by the Natural Resources Conservation Service (NRCS) and the Bureau of Reclamation (Reclamation) from on- and off-farm improvements in the Uinta Basin totaled about 135,000 tons in 2013 (81,900 tons from on-farm improvements and 53,300 tons from off-farm improvements). The reduction in dissolved-solids load resulting from on- and off-farm improvements facilitated by the NRCS and Reclamation in the Price River Basin from 1989 to 2013 was estimated to be 64,800 tons.The amount of sprinkler-irrigated land mapped in the drainage area or subbasin area for a gaging station was used to estimate the reduction in load resulting from the conversion from flood to sprinkler irrigation. Sprinkler-irrigated land mapped in the Uinta Basin totaled 109,630 acres in 2012. Assuming conversion to wheel-line sprinklers, a reduction in dissolved-solids load in the Uinta Basin of 95,800 tons in 2012 was calculated using the sprinkler-irrigation acreage and a pre-salinity-control project dissolved-solids yield of 1.04 tons per acre.A reduction of 72,800 tons in dissolved-solids load from irrigation improvements was determined from sprinkler-irrigated lands in the Ashley Valley and Jensen, Pelican Lake, and Pleasant Valley areas (mapped in 2012); and in the Price River Basin (mapped in 2011). This decrease in dissolved-solids load is 8,800 tons more than the decrease in unmonitored flow-normalized dissolved-solids load (-64,000 tons) determined for the Green River between the Jensen and Green River gaging stations.The net WY 1989–2013 change in flow-normalized dissolved-solids load at the Duchesne River near Randlett, UT, and the Green River between the Jensen and Green River, UT, gaging stations determined from mass-balance calculations was compared to reported reductions in dissolved-solids load from on- and off-farm improvements and estimated reductions in load determined from mapped sprinkler-irrigated areas in the Duchesne River Basin and the area draining to the Green River between the Jensen and Green River gaging stations. The combined NRCS and Reclamation estimates of reduction in dissolved-solids load from on- and off-farm improvements in the study area (200,000 tons) is more than the reduction in load estimated using the acreage with sprinkler improvements (136,000 tons) or the mass-balance of flow-normalized load (132,000 tons).

A high-speed photography study of cavitation in a dynamically loaded journal bearing

NASA Technical Reports Server (NTRS)

Sun, D. C.; Brewe, D. E.

1990-01-01

The earlier study made by Jacobson and Hamrock on the cavitation of liquid lubricant films in a dynamically loaded journal bearing was repeated with a quartz sleeve, which was more rigid than the Polymethylmethacrylate (PMMA) sleeve used previously. Various improvements of the test rig were made concomitantly so that the experimental errors could be better controlled and assessed. The updated speed photography experiment and its results are described.

A high speed photography study of cavitation in a dynamically loaded journal bearing

NASA Technical Reports Server (NTRS)

Sun, D. C.; Brewe, D. E.

1991-01-01

The earlier study made by Jacobson and Hamrock on the cavitation of liquid lubricant films in a dynamically loaded journal bearing was repeated with a quartz sleeve, which was more rigid than the Polymethylmethacrylate (PMMA) sleeve used previously. Various improvements of the test rig were made concomitantly so that the experimental errors could be better controlled and assessed. The updated speed photography experiment and its results are described.

Effect of loading orientations on the microstructure and property of Al−Cu single crystal during stress aging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jiqiang; Chen, Zhiguo, E-mail: zgchen@mail.csu.edu.cn; Hunan University of Humanities, Science and Technology, Loudi 417000

The precipitation behavior and property of Al−Cu alloy during stress aging under various loading orientations were investigated using single crystals. The resulting microstructures and the strength property were examined by transmission electron microscope (TEM) and compression test, respectively, and the effect of the distribution of θ′-plates on strength property were discussed. The results show that the precipitation distribution of θ′ was significantly affected by the loading orientation during stress aging of Al−Cu single crystals. Loading along close to 〈011〉{sub Al} directions provided more uniform precipitation distribution of θ′ as compared to loading along close to 〈001〉{sub Al} directions, and thereforemore » provided higher strengthening stress of the θ′-plates for the stress aging sample. The results suggested that regulating the distribution of θ′ and therefore improving strength property are possible via controlling the loading orientation during stress aging. - Highlights: • We studied the effect of loading directions on stress aging of Al−Cu single crystal. • Precipitation distribution of θ′ was noticeably affected by the loading direction. • Loading along close to 〈011〉{sub Al} directions reduced the stress-orienting effect. • The strength property is closely related to the precipitation distribution of θ′. • It is possible to regulate the distribution of θ′ and improve strength property.« less

Microfluidic assisted one-step fabrication of porous silicon@acetalated dextran nanocomposites for precisely controlled combination chemotherapy.

PubMed

Liu, Dongfei; Zhang, Hongbo; Mäkilä, Ermei; Fan, Jin; Herranz-Blanco, Bárbara; Wang, Chang-Fang; Rosa, Ricardo; Ribeiro, António J; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

2015-01-01

An advanced nanocomposite consisting of an encapsulated porous silicon (PSi) nanoparticle and an acid-degradable acetalated dextran (AcDX) matrix (nano-in-nano), was efficiently fabricated by a one-step microfluidic self-assembly approach. The obtained nano-in-nano PSi@AcDX composites showed improved surface smoothness, homogeneous size distribution, and considerably enhanced cytocompatibility. Furthermore, multiple drugs with different physicochemical properties have been simultaneously loaded into the nanocomposites with a ratiometric control. The release kinetics of all the payloads was predominantly controlled by the decomposition rate of the outer AcDX matrix. To facilitate the intracellular drug delivery, a nona-arginine cell-penetrating peptide (CPP) was chemically conjugated onto the surface of the nanocomposites by oxime click chemistry. Taking advantage of the significantly improved cell uptake, the proliferation of two breast cancer cell lines was markedly inhibited by the CPP-functionalized multidrug-loaded nanocomposites. Overall, this nano-in-nano PSi@polymer composite prepared by the microfluidic self-assembly approach is a universal platform for nanoparticles encapsulation and precisely controlled combination chemotherapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Effect of inspiratory muscle training on muscle strength and quality of life in patients with chronic airflow limitation: a randomized controlled trial].

PubMed

Serón, P; Riedemann, P; Muñoz, S; Doussoulin, A; Villarroel, P; Cea, X

2005-11-01

Chronic airflow limitation (CAL) is a significant cause of illness and death. Inspiratory muscle training has been described as a technique for managing CAL. The aim of the present study was to evaluate the effectiveness of inspiratory muscle training on improving physiological and functional variables. Randomized controlled trial in which 35 patients with CAL were assigned to receive either an experimental (n=17) or control (n=18) intervention. The experimental intervention consisted of 2 months of inspiratory muscle training using a device that administered a resistive load of 40% of maximal static inspiratory mouth pressure (PImax). Inspiratory muscle strength, exercise tolerance, respiratory function, and quality of life were assessed. Significant improvement in inspiratory muscle strength was observed in the experimental training group (P=.02). All patients improved over time in both groups (P<.001). PImax increased by 8.9 cm H2O per month of training. Likewise, the health-related quality of life scores improved by 0.56 points. Use of a threshold loading device is effective for strengthening inspiratory muscles as measured by PImax after the first month of training in patients with CAL. The long-term effectiveness of such training and its impact on quality of life should be studied in a larger number of patients.

Thermal and Structural Analysis of Helicopter Transmission Housings Using NASTRAN

NASA Technical Reports Server (NTRS)

Howells, R. W.; Sciarra, J. J.; Ng, G. S.

1976-01-01

The application of NASTRAN to improve the design of helicopter transmission housings is described. A finite element model of the complete forward rotor transmission housing for the Boeing Vertol CH-47C helicopter was used to study thermal distortion and stress, stress and deflection due to static and dynamic loads, load paths, and design optimization by the control of structural energy distribution. The analytical results are correlated with test data and used to reduce weight and to improve strength, service life, failsafety, and reliability. The techniques presented, although applied herein to helicopter transmissions, are sufficiently general to be applicable to any power transmission system.

The effects of low-repetition and light-load power training on bone mineral density in postmenopausal women with sarcopenia: a pilot study.

PubMed

Hamaguchi, Kanako; Kurihara, Toshiyuki; Fujimoto, Masahiro; Iemitsu, Motoyuki; Sato, Koji; Hamaoka, Takafumi; Sanada, Kiyoshi

2017-05-02

Age-related reduction in bone mineral density (BMD) is generally accelerated in women after menopause, and could be even more pronounced in individuals with sarcopenia. Light-load power training with a low number of repetitions would increase BMD, significantly reducing bone loss in individuals at risk of osteoporosis. This study investigated the effects of low-repetition, light-load power training on BMD in Japanese postmenopausal women with sarcopenia. The training group (n = 7) followed a progressive power training protocol that increased the load with a weighted vest, for two sessions per week, over the course of 6 weeks. The training exercise comprised five kinds of exercises (squats, front lunges, side lunges, calf raises, and toe raises), and each exercise contained eight sets of three repetitions with a 15-s rest between each set. The control group (n = 8) did not undergo any training intervention. We measured BMD, muscle strength, and anthropometric data. Within-group changes in pelvis BMD and knee extensor strength were significantly greater in the training group than the control group (p = 0.029 and 0.030 for pelvis BMD and knee extensor strength, respectively). After low-repetition, light-load power training, we noted improvements in pelvis BMD (1.6%) and knee extensor strength (15.5%). No significant within- or between-group differences were observed for anthropometric data or forearm BMD. Six weeks of low-repetition, light-load power training improved pelvis BMD and knee extensor strength in postmenopausal women with sarcopenia. Since this training program does not require high-load exercise and is therefore easily implementable as daily exercise, it could be an effective form of exercise for sedentary adults at risk for osteoporosis who are fearful of heavy loads and/or training that could cause fatigue. This trial was registered with the University Hospital Medical Information Network on 31 October 2016 ( UMIN000024651 ).

Potential effects of structural controls and street sweeping on stormwater loads to the lower Charles River, Massachusetts

USGS Publications Warehouse

Zarriello, Phillip J.; Breault, Robert F.; Weiskel, Peter K.

2002-01-01

The water quality of the lower Charles River is periodically impaired by combined sewer overflows (CSOs) and non-CSO stormwater runoff. This study examined the potential non-CSO load reductions of suspended solids, fecal coliform bacteria, total phosphorus, and total lead that could reasonably be achieved by implementation of stormwater best management practices, including both structural controls and systematic street sweeping. Structural controls were grouped by major physical or chemical process; these included infiltration-filtration (physical separation), biofiltration-bioretention (biological mechanisms), or detention-retention (physical settling). For each of these categories, upper and lower quartiles, median, and average removal efficiencies were compiled from three national databases of structural control performance. Removal efficiencies obtained indicated a wide range of performance. Removal was generally greatest for infiltration-filtration controls and suspended solids, and least for biofiltration-bioretention controls and fecal coliform bacteria. Street sweeping has received renewed interest as a water-quality control practice because of reported improvements in sweeper technology and the recognition that opportunities for implementing structural controls are limited in highly urbanized areas. The Stormwater Management Model that was developed by the U.S. Geological Survey for the lower Charles River Watershed was modified to simulate the effects of street sweeping in a single-family land-use basin. Constituent buildup and washoff variable values were calibrated to observed annual and storm-event loads. Once calibrated, the street sweeping model was applied to various permutations of four sweeper efficiencies and six sweeping frequencies that ranged from every day to once every 30 days. Reduction of constituent loads to the lower Charles River by the combined hypothetical practices of structural controls and street sweeping was estimated for a range of removal efficiencies because of their inherent variability and uncertainty. This range of efficiencies, with upper and lower estimates, provides reasonable bounds on the load that could be removed by the practices examined. The upper estimated load reduction from combined street sweeping and structural controls, as a percentage of the total non-CSO load entering the lower Charles River downstream of Watertown Dam, was 44 percent for suspended solids, 34 percent for total lead, 14 percent for total phosphorus, and 17 percent for fecal coliform bacteria. The lower estimated load reduction from combined street sweeping and structural controls from non-CSO sources downstream of Watertown Dam, was 14 percent for suspended solids, 11 percent for total lead, 4.9 percent for total phosphorus, and 7.5 percent for fecal coliform bacteria. Load reductions by these combined management practices can be a small as 1.4 percent for total phosphorus to about 4 percent for the other constituents if the total load above Watertown Dam is added to the load from below the dam. Although the reductions in stormwater loads to the lower Charles River from the control practices examined appear to be minor, these practices would likely provide water-quality benefits to portions of the river during those times that they are most impaired-during and immediately after storms. It should also be recognized that only direct measurements of changes in stormwater loads before and after implementation of control practices can provide definitive evidence of the beneficial effects of these practices on water-quality conditions in the lower Charles River.

Back muscle response to sudden trunk loading can be modified by training among healthcare workers.

PubMed

Pedersen, Mogens Theisen; Essendrop, Morten; Skotte, Jørgen H; Jørgensen, Kurt; Schibye, Bente; Fallentin, Nils

2007-06-01

Experimental study of the effect of physical training on the reaction to sudden back loading. To investigate the effect and sustainability of "on the job training" on the reaction to sudden back loading among employees at a geriatric ward. Available data suggest that a delayed muscle reflex response to sudden trunk loading may increase the risk of low back injuries. We have previously shown that training may alter the response to sudden trunk loading in healthy subjects and decrease the time elapsed until stopping of the forward movement of the trunk (stopping time). Data on the possibilities of a training-induced improvement in the reflex response among workers exposed to sudden trunk loading on the job are, however, nonexistent, and there is no evidence of long-term benefits, i.e., the sustainability of a positive training effect. The study included 23 participants and 14 controls. All were healthy without prior history of low back pain (LBP). The training group participated in a total of 18 training sessions during a 9-week period. The training focused on reactions to a variety of sudden trunk loadings. Before and after the training intervention and at a 1-year follow-up, all subjects were tested for their reaction to expected and unexpected sudden trunk loading by applying a horizontal force of 58 N to the upper back of the subjects and measuring the electromyographic (EMG) response from the erector spinae muscles. In the training group, the stopping time and the distance moved after unexpected sudden trunk loading decreased significantly (13%-19%, P = 0.02). The improved stopping time was associated with marked changes in the time-wise distribution of the EMG signal after training. In addition, the follow-up study showed a high sustainability of the training effect. The results demonstrated a training-induced improvement of the response to sudden trunk loading that may be beneficial in workers, such as nurses, who are exposed to sudden trunk perturbations during patient handling.

Study of the two-phase dummy load shut-down strategy for proton exchange membrane fuel cells

NASA Astrophysics Data System (ADS)

Zhang, Q.; Lin, R.; Cui, X.; Xia, S. X.; Yang, Z.; Chang, Y. T.

2017-02-01

This paper presents a new system strategy designed to alleviate the performance decay caused by start-up/shut-down (SU/SD) conditions in proton exchange membrane fuel cells (PEMFCs). The innovative method was tested using a two-phase dummy load composed of a linearly declined main load and a fixed small auxiliary load. The initial value of the main load must be controlled within a proper range, and a closed-ended air exhaust is necessary. According to the analysis of in-situ current density distribution during SD processes, the two-phase dummy load can continuously fit the process of oxygen reduction in the cathode, whereas the conventional dummy load leads to local air starvation. Polarization curves and cyclic voltammetry (CV) were employed to evaluate the performance decay during SU/SD repetition. After tests of 900 cycles, the highest voltage degradation rate of the PEMFC was 3.33 μV cycle-1 (800 mA cm-2), and the electrochemical surface area (ECSA) loss was 0.0046 m2 g-1 cycle-1 with the two-phase dummy load strategy. After comparing results with similar work on a single PEMFC, the authors confirmed the preeminent effectiveness of this strategy. This strategy will also improve fuel cell stack performance due to controllable SD duration and comparatively low performance decay rates.

Team performance in networked supervisory control of unmanned air vehicles: effects of automation, working memory, and communication content.

PubMed

McKendrick, Ryan; Shaw, Tyler; de Visser, Ewart; Saqer, Haneen; Kidwell, Brian; Parasuraman, Raja

2014-05-01

Assess team performance within a net-worked supervisory control setting while manipulating automated decision aids and monitoring team communication and working memory ability. Networked systems such as multi-unmanned air vehicle (UAV) supervision have complex properties that make prediction of human-system performance difficult. Automated decision aid can provide valuable information to operators, individual abilities can limit or facilitate team performance, and team communication patterns can alter how effectively individuals work together. We hypothesized that reliable automation, higher working memory capacity, and increased communication rates of task-relevant information would offset performance decrements attributed to high task load. Two-person teams performed a simulated air defense task with two levels of task load and three levels of automated aid reliability. Teams communicated and received decision aid messages via chat window text messages. Task Load x Automation effects were significant across all performance measures. Reliable automation limited the decline in team performance with increasing task load. Average team spatial working memory was a stronger predictor than other measures of team working memory. Frequency of team rapport and enemy location communications positively related to team performance, and word count was negatively related to team performance. Reliable decision aiding mitigated team performance decline during increased task load during multi-UAV supervisory control. Team spatial working memory, communication of spatial information, and team rapport predicted team success. An automated decision aid can improve team performance under high task load. Assessment of spatial working memory and the communication of task-relevant information can help in operator and team selection in supervisory control systems.

Inertial torque during reaching directly impacts grip-force adaptation to weightless objects.

PubMed

Giard, T; Crevecoeur, F; McIntyre, J; Thonnard, J-L; Lefèvre, P

2015-11-01

A hallmark of movement control expressed by healthy humans is the ability to gradually improve motor performance through learning. In the context of object manipulation, previous work has shown that the presence of a torque load has a direct impact on grip-force control, characterized by a significantly slower grip-force adjustment across lifting movements. The origin of this slower adaptation rate remains unclear. On the one hand, information about tangential constraints during stationary holding may be difficult to extract in the presence of a torque. On the other hand, inertial torque experienced during movement may also potentially disrupt the grip-force adjustments, as the dynamical constraints clearly differ from the situation when no torque load is present. To address the influence of inertial torque loads, we instructed healthy adults to perform visually guided reaching movements in weightlessness while holding an unbalanced object relative to the grip axis. Weightlessness offered the possibility to remove gravitational constraints and isolate the effect of movement-related feedback on grip force adjustments. Grip-force adaptation rates were compared with a control group who manipulated a balanced object without any torque load and also in weightlessness. Our results clearly show that grip-force adaptation in the presence of a torque load is significantly slower, which suggests that the presence of torque loads experienced during movement may alter our internal estimates of how much force is required to hold an unbalanced object stable. This observation may explain why grasping objects around the expected location of the center of mass is such an important component of planning and control of manipulation tasks.

Type-2 fuzzy logic control based MRAS speed estimator for speed sensorless direct torque and flux control of an induction motor drive.

PubMed

Ramesh, Tejavathu; Kumar Panda, Anup; Shiva Kumar, S

2015-07-01

In this research study, a model reference adaptive system (MRAS) speed estimator for speed sensorless direct torque and flux control (DTFC) of an induction motor drive (IMD) using two adaptation mechanism schemes are proposed to replace the conventional proportional integral controller (PIC). The first adaptation mechanism scheme is based on Type-1 fuzzy logic controller (T1FLC), which is used to achieve high performance sensorless drive in both transient as well as steady state conditions. However, the Type-1 fuzzy sets are certain and unable to work effectively when higher degree of uncertainties presents in the system which can be caused by sudden change in speed or different load disturbances, process noise etc. Therefore, a new Type-2 fuzzy logic controller (T2FLC) based adaptation mechanism scheme is proposed to better handle the higher degree of uncertainties and improves the performance and also robust to various load torque and sudden change in speed conditions, respectively. The detailed performances of various adaptation mechanism schemes are carried out in a MATLAB/Simulink environment with a speed sensor and speed sensorless modes of operation when an IMD is operating under different operating conditions, such as, no-load, load and sudden change in speed, respectively. To validate the different control approaches, the system also implemented on real-time system and adequate results are reported for its validation. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Wind Turbine Controller to Mitigate Structural Loads on a Floating Wind Turbine Platform

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Paul A.; Peiffer, Antoine; Schlipf, David

This paper summarizes the control design work that was performed to optimize the controller of a wind turbine on the WindFloat structure. The WindFloat is a semi-submersible floating platform designed to be a support structure for a multi-megawatt power-generating wind turbine. A controller developed for a bottom-fixed wind turbine configuration was modified for use when the turbine is mounted on the WindFloat platform. This results in an efficient platform heel resonance mitigation scheme. In addition several control modules, designed with a coupled linear model, were added to the fixed-bottom baseline controller. The approach was tested in a fully coupled nonlinearmore » aero-hydroelastic simulation tool in which wind and wave disturbances were modeled. This testing yielded significant improvements in platform global performance and tower-base-bending loading.« less

Multi-load Groups Coordinated Load Control Strategy Considering Power Network Constraints

NASA Astrophysics Data System (ADS)

Liu, Meng; Zhao, Binchao; Wang, Jun; Zhang, Guohui; Wang, Xin

2017-05-01

Loads with energy storage property can actively participate in power balance for power systems, this paper takes air conditioner as a controllable load example, proposing a multi-load groups coordinated load control strategy considering power network constraints. Firstly, two load control modes considering recovery of load diversity are designed, blocking power oscillation of aggregated air conditioners. As the same time, air conditioner temperature setpoint recovery control strategy is presented to avoid power recovery peak. Considering inherent characteristics of two load control modes, an coordinated load control mode is designed by combining the both. Basing on this, a multi-load groups coordinated load control strategy is proposed. During the implementing of load control, power network constraints should be satisfied. An indice which can reflect the security of power system operating is defined. By minimizing its value through optimization, the change of air conditioning loads’ aggregated power on each load bus can be calculated. Simulations are conducted on an air conditioners group and New England 10-generator 39-bus system, verifying the effectiveness of the proposed multi-load groups coordinated load control strategy considering power network constraints.

Power Quality Improvement Utilizing Photovoltaic Generation Connected to a Weak Grid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muljadi, Eduard; Tumbelaka, Hanny H.; Gao, Wenzhong

Microgrid research and development in the past decades have been one of the most popular topics. Similarly, the photovoltaic generation has been surging among renewable generation in the past few years, thanks to the availability, affordability, technology maturity of the PV panels and the PV inverter in the general market. Unfortunately, quite often, the PV installations are connected to weak grids and may have been considered as the culprit of poor power quality affecting other loads in particular sensitive loads connected to the same point of common coupling (PCC). This paper is intended to demystify the renewable generation, and turnsmore » the negative perception into positive revelation of the superiority of PV generation to the power quality improvement in a microgrid system. The main objective of this work is to develop a control method for the PV inverter so that the power quality at the PCC will be improved under various disturbances. The method is to control the reactive current based on utilizing the grid current to counteract the negative impact of the disturbances. The proposed control method is verified in PSIM platform. Promising results have been obtained.« less

Effects of prescribed fire on wildlife and wildlife habitat in selected ecosystems of North America

Treesearch

William M. Block; L. Mike Conner; Paul A. Brewer; Paulette Ford; Jonathan Haufler; Andrea Litt; Ronald E. Masters; Laura R. Mitchell; Jane Park

2016-01-01

Prescribed fire is applied widely as a management tool in North America to meet various objectives such as reducing fuel loads and fuel continuity, returning fire to an ecosystem, enhancing wildlife habitats, improving forage, preparing seedbeds, improving watershed conditions, enhancing nutrient cycling, controlling exotic weeds, and enhancing resilience from...

Effects of treadmill training with load addition on non-paretic lower limb on gait parameters after stroke: A randomized controlled clinical trial.

PubMed

Ribeiro, Tatiana S; Silva, Emília M G S; Silva, Isaíra A P; Costa, Mayara F P; Cavalcanti, Fabrícia A C; Lindquist, Ana R

2017-05-01

The addition of load on the non-paretic lower limb for the purpose of restraining this limb and stimulating the use of the paretic limb has been suggested to improve hemiparetic gait. However, the results are conflicting and only short-term effects have been observed. This study aims to investigate the effects of adding load on non-paretic lower limb during treadmill gait training as a multisession intervention on kinematic gait parameters after stroke. With this aim, 38 subacute stroke patients (mean time since stroke: 4.5 months) were randomly divided into two groups: treadmill training with load (equivalent to 5% of body weight) on the non-paretic ankle (experimental group) and treadmill training without load (control group). Both groups performed treadmill training during 30min per day, for two consecutive weeks (nine sessions). Spatiotemporal and angular gait parameters were assessed by a motion system analysis at baseline, post-training (at the end of 9days of interventions) and follow-up (40days after the end of interventions). Several post-training effects were demonstrated: patients walked faster and with longer paretic and non-paretic steps compared to baseline, and maintained these gains at follow-up. In addition, patients exhibited greater hip and knee joint excursion in both limbs at post-training, while maintaining most of these benefits at follow-up. All these improvements were observed in both groups. Although the proposal gait training program has provided better gait parameters for these subacute stroke patients, our data indicate that load addition used as a restraint may not provide additional benefits to gait training. Copyright © 2017 Elsevier B.V. All rights reserved.

Real-Time Load-Side Control of Electric Power Systems

NASA Astrophysics Data System (ADS)

Zhao, Changhong

Two trends are emerging from modern electric power systems: the growth of renewable (e.g., solar and wind) generation, and the integration of information technologies and advanced power electronics. The former introduces large, rapid, and random fluctuations in power supply, demand, frequency, and voltage, which become a major challenge for real-time operation of power systems. The latter creates a tremendous number of controllable intelligent endpoints such as smart buildings and appliances, electric vehicles, energy storage devices, and power electronic devices that can sense, compute, communicate, and actuate. Most of these endpoints are distributed on the load side of power systems, in contrast to traditional control resources such as centralized bulk generators. This thesis focuses on controlling power systems in real time, using these load side resources. Specifically, it studies two problems. (1) Distributed load-side frequency control: We establish a mathematical framework to design distributed frequency control algorithms for flexible electric loads. In this framework, we formulate a category of optimization problems, called optimal load control (OLC), to incorporate the goals of frequency control, such as balancing power supply and demand, restoring frequency to its nominal value, restoring inter-area power flows, etc., in a way that minimizes total disutility for the loads to participate in frequency control by deviating from their nominal power usage. By exploiting distributed algorithms to solve OLC and analyzing convergence of these algorithms, we design distributed load-side controllers and prove stability of closed-loop power systems governed by these controllers. This general framework is adapted and applied to different types of power systems described by different models, or to achieve different levels of control goals under different operation scenarios. We first consider a dynamically coherent power system which can be equivalently modeled with a single synchronous machine. We then extend our framework to a multi-machine power network, where we consider primary and secondary frequency controls, linear and nonlinear power flow models, and the interactions between generator dynamics and load control. (2) Two-timescale voltage control: The voltage of a power distribution system must be maintained closely around its nominal value in real time, even in the presence of highly volatile power supply or demand. For this purpose, we jointly control two types of reactive power sources: a capacitor operating at a slow timescale, and a power electronic device, such as a smart inverter or a D-STATCOM, operating at a fast timescale. Their control actions are solved from optimal power flow problems at two timescales. Specifically, the slow-timescale problem is a chance-constrained optimization, which minimizes power loss and regulates the voltage at the current time instant while limiting the probability of future voltage violations due to stochastic changes in power supply or demand. This control framework forms the basis of an optimal sizing problem, which determines the installation capacities of the control devices by minimizing the sum of power loss and capital cost. We develop computationally efficient heuristics to solve the optimal sizing problem and implement real-time control. Numerical experiments show that the proposed sizing and control schemes significantly improve the reliability of voltage control with a moderate increase in cost.

Analysis of collaborative communication for linguistic cues of cognitive load.

PubMed

Khawaja, M Asif; Chen, Fang; Marcus, Nadine

2012-08-01

Analyses of novel linguistic and grammatical features, extracted from transcribed speech of people working in a collaborative environment, were performed for cognitive load measurement Prior studies have attempted to assess users' cognitive load with several measures, but most of them are intrusive and disrupt normal task flow. An effective measurement of people's cognitive load can help improve their performance by deploying appropriate output and support strategies accordingly. The authors studied 33 members of bushfire management teams working collaboratively in computerized incident control rooms and involved in complex bushfire management tasks. The participants' communication was analyzed for some novel linguistic features as potential indices of cognitive load, which included sentence length, use of agreement and disagreement phrases, and use of personal pronouns, including both singular and plural pronoun types. Results showed users' different linguistic and grammatical patterns with various cognitive load levels. Specifically, with high load, people spoke more and used longer sentences, used more words that indicated disagreement with other team members, and exhibited increased use of plural personal pronouns and decreased use of singular pronouns. The article provides encouraging evidence for the use of linguistic and grammatical analysis for measuring users' cognitive load and proposes some novel features as cognitive load indices. The proposed approach may be applied to many data-intense and safety-critical task scenarios, such as emergency management departments, for example, bushfire or traffic incident management centers; air traffic control rooms; and call centers, where speech is used as part of everyday tasks.

Load controller and method to enhance effective capacity of a photovoltaic power supply using a dynamically determined expected peak loading

DOEpatents

Perez, Richard

2005-05-03

A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply.

Combining Load and Motor Encoders to Compensate Nonlinear Disturbances for High Precision Tracking Control of Gear-Driven Gimbal

PubMed Central

Tang, Tao; Chen, Sisi; Huang, Xuanlin; Yang, Tao; Qi, Bo

2018-01-01

High-performance position control can be improved by the compensation of disturbances for a gear-driven control system. This paper presents a mode-free disturbance observer (DOB) based on sensor-fusion to reduce some errors related disturbances for a gear-driven gimbal. This DOB uses the rate deviation to detect disturbances for implementation of a high-gain compensator. In comparison with the angular position signal the rate deviation between load and motor can exhibits the disturbances exiting in the gear-driven gimbal quickly. Due to high bandwidth of the motor rate closed loop, the inverse model of the plant is not necessary to implement DOB. Besides, this DOB requires neither complex modeling of plant nor the use of additive sensors. Without rate sensors providing angular rate, the rate deviation is easily detected by encoders mounted on the side of motor and load, respectively. Extensive experiments are provided to demonstrate the benefits of the proposed algorithm. PMID:29498643

Combining Load and Motor Encoders to Compensate Nonlinear Disturbances for High Precision Tracking Control of Gear-Driven Gimbal.

PubMed

Tang, Tao; Chen, Sisi; Huang, Xuanlin; Yang, Tao; Qi, Bo

2018-03-02

High-performance position control can be improved by the compensation of disturbances for a gear-driven control system. This paper presents a mode-free disturbance observer (DOB) based on sensor-fusion to reduce some errors related disturbances for a gear-driven gimbal. This DOB uses the rate deviation to detect disturbances for implementation of a high-gain compensator. In comparison with the angular position signal the rate deviation between load and motor can exhibits the disturbances exiting in the gear-driven gimbal quickly. Due to high bandwidth of the motor rate closed loop, the inverse model of the plant is not necessary to implement DOB. Besides, this DOB requires neither complex modeling of plant nor the use of additive sensors. Without rate sensors providing angular rate, the rate deviation is easily detected by encoders mounted on the side of motor and load, respectively. Extensive experiments are provided to demonstrate the benefits of the proposed algorithm.

Nitrate and phosphorus transport through subsurface drains under free and controlled drainage.

PubMed

Saadat, Samaneh; Bowling, Laura; Frankenberger, Jane; Kladivko, Eileen

2018-05-28

Controlled drainage (CD) is a structural conservation practice in which the drainage outlet is managed in order to reduce drain flow volume and nutrient loads to water bodies. The goal of this study was to evaluate the potential of CD to improve water quality for two different seasons and levels of outlet control, using ten years of data collected from an agricultural drained field in eastern Indiana with two sets of paired plots. The Rank Sum test was used to quantify the impact of CD on cumulative annual drain flow and nitrate-N and phosphorus loads. CD plots had a statistically significant (at 5% level) lower annual drain flow (eastern pair: 39%; western pair: 25%) and nitrate load (eastern pair: 43%; western pair: 26%) compared to free draining (FD) plots, while annual soluble reactive phosphorus (SRP) and total phosphorus (TP) loads were not significantly different. An ANCOVA model was used to evaluate the impact of CD on daily drain flow, nitrate-N, SRP and TP concentrations and loads during the two different periods of control. The average percent reduction of daily drain flow was 68% in the eastern pair and 58% in the western pair during controlled drainage at the higher outlet level (winter) and 64% and 58% at the lower outlet level (summer) in the eastern and western pairs, respectively. Nitrate load reduction was similar to drain flow reduction, while the effect of CD on SRP and TP loads was not significant except for the increase in SRP in one pair. These results from a decade-long field monitoring and two different statistical methods enhance our knowledge about water quality impacts of CD system and support this management practice as a reliable system for reducing nitrate loss through subsurface drains, mainly caused by flow reduction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Optimally oriented grooves on dental implants improve bone quality around implants under repetitive mechanical loading.

PubMed

Kuroshima, Shinichiro; Nakano, Takayoshi; Ishimoto, Takuya; Sasaki, Muneteru; Inoue, Maaya; Yasutake, Munenori; Sawase, Takashi

2017-01-15

The aim was to investigate the effect of groove designs on bone quality under controlled-repetitive load conditions for optimizing dental implant design. Anodized Ti-6Al-4V alloy implants with -60° and +60° grooves around the neck were placed in the proximal tibial metaphysis of rabbits. The application of a repetitive mechanical load was initiated via the implants (50N, 3Hz, 1800 cycles, 2days/week) at 12weeks after surgery for 8weeks. Bone quality, defined as osteocyte density and degree of biological apatite (BAp) c-axis/collagen fibers, was then evaluated. Groove designs did not affect bone quality without mechanical loading; however, repetitive mechanical loading significantly increased bone-to-implant contact, bone mass, and bone mineral density (BMD). In +60° grooves, the BAp c-axis/collagen fibers preferentially aligned along the groove direction with mechanical loading. Moreover, osteocyte density was significantly higher both inside and in the adjacent region of the +60° grooves, but not -60° grooves. These results suggest that the +60° grooves successfully transmitted the load to the bone tissues surrounding implants through the grooves. An optimally oriented groove structure on the implant surface was shown to be a promising way for achieving bone tissue with appropriate bone quality. This is the first report to propose the optimal design of grooves on the necks of dental implants for improving bone quality parameters as well as BMD. The findings suggest that not only BMD, but also bone quality, could be a useful clinical parameter in implant dentistry. Although the paradigm of bone quality has shifted from density-based assessments to structural evaluations of bone, clarifying bone quality based on structural bone evaluations remains challenging in implant dentistry. In this study, we firstly demonstrated that the optimal design of dental implant necks improved bone quality defined as osteocytes and the preferential alignment degree of biological apatite c-axis/collagen fibers using light microscopy, polarized light microscopy, and a microbeam X-ray diffractometer system, after application of controlled mechanical load. Our new findings suggest that bone quality around dental implants could become a new clinical parameter as well as bone mineral density in order to completely account for bone strength in implant dentistry. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The Liquid Nitrogen System for Chamber A: A Change from Original Forced Flow Design to a Natural Flow (Thermo Siphon) System

NASA Technical Reports Server (NTRS)

Homan, Jonathan; Montz, Michael; Sidi-Yekhlef, Ahmed; Ganni, Venkatarao (Rao); Knudsen, Peter; Garcia, Sam; Linza, Robert; Meagher, Daniel; Lauterbauch, John

2008-01-01

NASA Johnson Space Center (JSC) in Houston is currently supplementing its 20K helium refrigeration system to meet the new requirements for testing the James Web Space Telescope in the environmental control Chamber-A (65 dia x 120 high) in Building 32. The new system is required to meet the various operating modes which include a high 20K heat load, a required temperature stability at the load, rapid (but controlled) cool down and warm up and bake out of the chamber. This paper will present the proposed modifications to the existing helium system(s) to incorporate the new requirements and the integration of the new helium refrigerator with the existing two 3.5KW 20K helium refrigerators. In addition, the floating pressure process control philosophy to achieve high efficiency over the operating range (40% to 100% of the refrigeration system capacity), and the required temperature stability of +/- 0.25 K at the load will be discussed. The refrigeration systems ability to naturally seek the operating conditions under various loads and thus minimizing operator involvement and the over all improvements to the system operability and the reliability will be explained.

Controlled release of agrochemicals intercalated into montmorillonite interlayer space.

PubMed

Wanyika, Harrison

2014-01-01

Periodic application of agrochemicals has led to high cost of production and serious environmental pollution. In this study, the ability of montmorillonite (MMT) clay to act as a controlled release carrier for model agrochemical molecules has been investigated. Urea was loaded into MMT by a simple immersion technique while loading of metalaxyl was achieved by a rotary evaporation method. The successful incorporation of the agrochemicals into the interlayer space of MMT was confirmed by several techniques, such as, significant expansion of the interlayer space, reduction of Barrett-Joyner-Halenda (BJH) pore volumes and Brunauer-Emmett-Teller (BET) surface areas, and appearance of urea and metalaxyl characteristic bands on the Fourier-transform infrared spectra of the urea loaded montmorillonite (UMMT) and metalaxyl loaded montmorillonite (RMMT) complexes. Controlled release of the trapped molecules from the matrix was done in water and in the soil. The results reveal slow and sustained release behaviour for UMMT for a period of 10 days in soil. For a period of 30 days, MMT delayed the release of metalaxyl in soil by more than 6 times. It is evident that MMT could be used to improve the efficiency of urea and metalaxyl delivery in the soil.

Controlled Release of Agrochemicals Intercalated into Montmorillonite Interlayer Space

PubMed Central

2014-01-01

Periodic application of agrochemicals has led to high cost of production and serious environmental pollution. In this study, the ability of montmorillonite (MMT) clay to act as a controlled release carrier for model agrochemical molecules has been investigated. Urea was loaded into MMT by a simple immersion technique while loading of metalaxyl was achieved by a rotary evaporation method. The successful incorporation of the agrochemicals into the interlayer space of MMT was confirmed by several techniques, such as, significant expansion of the interlayer space, reduction of Barrett-Joyner-Halenda (BJH) pore volumes and Brunauer-Emmett-Teller (BET) surface areas, and appearance of urea and metalaxyl characteristic bands on the Fourier-transform infrared spectra of the urea loaded montmorillonite (UMMT) and metalaxyl loaded montmorillonite (RMMT) complexes. Controlled release of the trapped molecules from the matrix was done in water and in the soil. The results reveal slow and sustained release behaviour for UMMT for a period of 10 days in soil. For a period of 30 days, MMT delayed the release of metalaxyl in soil by more than 6 times. It is evident that MMT could be used to improve the efficiency of urea and metalaxyl delivery in the soil. PMID:24696655

Electrophoretic deposition of gentamicin-loaded bioactive glass/chitosan composite coatings for orthopaedic implants.

PubMed

Pishbin, Fatemehsadat; Mouriño, Viviana; Flor, Sabrina; Kreppel, Stefan; Salih, Vehid; Ryan, Mary P; Boccaccini, Aldo R

2014-06-11

Despite their widespread application, metallic orthopaedic prosthesis failure still occurs because of lack of adequate bone-bonding and the incidence of post-surgery infections. The goal of this research was to develop multifunctional composite chitosan/Bioglass coatings loaded with gentamicin antibiotic as a suitable strategy to improve the surface properties of metallic implants. Electrophoretic deposition (EPD) was applied as a single-step technology to simultaneously deposit the biopolymer, bioactive glass particles, and the antibiotic on stainless steel substrate. The microstructure and composition of the coatings were characterized using SEM/EDX, XRD, FTIR, and TGA/DSC, respectively. The in vitro bioactivity of the coatings was demonstrated by formation of hydroxyapatite after immersion in simulated body fluid (SBF) in a short period of 2 days. High-performance liquid chromatography (HPLC) measurements indicated the release of 40% of the loaded gentamicin in phosphate buffered saline (PBS) within the first 5 days. The developed composite coating supported attachment and proliferation of MG-63 cells up to 10 days. Moreover, disc diffusion test showed improved bactericidal effect of gentamicin-loaded composite coatings against S. aureus compared to control non-gentamicin-loaded coatings.

Load controller and method to enhance effective capacity of a photovotaic power supply using a dynamically determined expected peak loading

DOEpatents

Perez, Richard

2003-04-01

A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply. The expected peak loading of the variable load can be dynamically determined within a defined time interval with reference to variations in the variable load.

Control of xylem Na+ loading and transport to the shoot in rice and barley as a determinant of differential salinity stress tolerance.

PubMed

Ishikawa, Tetsuya; Shabala, Sergey

2018-05-15

Control of xylem Na + loading has often been named as the essential components of salinity tolerance mechanism. However, it is less clear to what extent the difference in this trait may determine differential salinity tolerance between species. In this study barley (Hordeum vulgare L. cv. CM72) and rice (Oryza sativa L. cv Dongjin) plants were grown under two levels of salinity. Na + and K + concentrations in the xylem sap, and shoot and root tissues were measured at different time points after stress onset. Salt-exposed rice plants prevented xylem Na + loading for several days, but failed to control this process in the longer term, ultimately resulting in a massive Na + shoot loading. Barley plants quickly increased xylem Na + concentration and its delivery to the shoot (most likely for the purpose of osmotic adjustment) but were able to reduce this process later on, keeping most of accumulated Na + in the root, thus maintaining non-toxic shoot Na + level. Rice plants increased shoot K + concentration, while barley plants maintained higher root K + concentration. Control of xylem Na + loading is remarkably different between rice and barley; this difference may differentiate the extent of the salinity tolerance between species. This trait should be investigated in more details to be used in the breeding programs aimed to improve salinity tolerance in crops. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Active structural control of a floating wind turbine with a stroke-limited hybrid mass damper

NASA Astrophysics Data System (ADS)

Hu, Yaqi; He, Erming

2017-12-01

Floating wind turbines are subjected to more severe structural loads than fixed-bottom wind turbines due to additional degrees of freedom (DOFs) of their floating foundations. It's a promising way of using active structural control method to improve the structural responses of floating wind turbines. This paper investigates an active vibration control strategy for a barge-type floating wind turbine by setting a stroke-limited hybrid mass damper (HMD) in the turbine's nacelle. Firstly, a contact nonlinear modeling method for the floating wind turbine with clearance between the HMD and the stroke limiters is presented based on Euler-Lagrange's equations and an active control model of the whole system is established. The structural parameters are validated for the active control model and an equivalent load coefficient method is presented for identifying the wind and wave disturbances. Then, a state-feedback linear quadratic regulator (LQR) controller is designed to reduce vibration and loads of the wind turbine, and two optimization methods are combined to optimize the weighting coefficients when considering the stroke of the HMD and the active control power consumption as constraints. Finally, the designed controllers are implemented in high fidelity simulations under five typical wind and wave conditions. The results show that active HMD control strategy is shown to be achievable and the designed controllers could further reduce more vibration and loads of the wind turbine under the constraints of stroke limitation and power consumption. "V"-shaped distribution of the TMD suppression effect is inconsistent with the Weibull distribution in practical offshore floating wind farms, and the active HMD control could overcome this shortcoming of the passive TMD.

Load Carriage: An Integrated Risk Management Approach.

PubMed

Orr, Robin M; Pope, Rodney R

2015-11-01

Military load carriage (LC) gives rise to substantial risks to soldier health, tactical performance, and mission success. The aim of this article was to extract and synthesize the key findings of a series of LC research reports previously published by the authors. Five reviews and 6 studies were included, with key findings extracted and synthesized in tabulated and critical narrative form. The weight of a soldier's load is a source of risk for soldier's injuries and tactical task performance. The resulting level of risk is influenced by risk modifiers (like speed of march, terrain grade, and task type and duration) and risk controls (like administrative controls and physical conditioning). In the Australian context, these risk controls were limited, with soldiers carrying heavier loads than those mandated by doctrine and policy, and LC conditioning not meeting best practice. The diversity of LC contexts, combined with the influence of risk modifiers and risk controls, means that levels of risk associated with LC are not consistent and must be assessed on a case-by-case basis. Load weight and marching routes (terrains, gradients), distances, speed, and duration are all potentially treatable sources of LC-related risk. Potential risk treatments include not only commanders directly addressing these specific sources of risk to the extent feasible, on a case-by-case basis, when planning or conducting LC tasks but also improving administration controls (i.e., doctrine and policies) and personal protection (i.e., the physical conditioning of the soldier) as part of the hierarchy of controls. Practical application would involve commanders developing and implementing dedicated LC doctrine and policies and implementing and enforcing LC conditioning programs that meets best practice.

Flash NanoPrecipitation (FNP) for bioengineering nanoparticles to enhance the bioavailability

NASA Astrophysics Data System (ADS)

Feng, Jie; Zhang, Yingyue; McManus, Simone; Prud'Homme, Robert

2017-11-01

Nanoparticles for the delivery of therapeutics have been one of the successful areas in biomedical nanotechnology. Nanoparticles improve bioavailability by 1) the higher surface-to-volume ratios, enhancing dissolution rates, and 2) trapping drug molecules in higher energy, amorphous states for a higher solubility. However, conventional direct precipitation to prepare nanoparticles has the issues of low loading and encapsulation efficiency. Here we demonstrate a kinetically controlled and rapid-precipitation process called Flash NanoPrecipitation (FNP), to offer a multi-phase mixing platform for bioengineering nanoparticles. With the designed geometry in the micro-mixer, we can generate nanoparticles with a narrow size distribution, while maintaining high loading and encapsulation efficiency. By controlling the time scales in FNP, we can tune the nanoparticle size and the robustness of the process. Remarkably, the dissolution rates of the nanoparticles are significantly improved compared with crystalline drug powders. Furthermore, we investigate how to recover the drug-loaded nanoparticles from the aqueous dispersions. Regarding the maintenance of the bioavailability, we discuss the advantages and disadvantages of each drying process. These results suggest that FNP offers a versatile and scalable nano-fabrication platform for biomedical engineering.

The potential of magneto-electric nanocarriers for drug delivery

PubMed Central

Kaushik, Ajeet; Jayant, Rahul Dev; Sagar, Vidya; Nair, Madhavan

2015-01-01

Introduction The development and design of personalized nanomedicine for better health quality is receiving great attention. In order to deliver and release a therapeutic concentration at the target site, novel nanocarriers (NCs) were designed, for example, magneto-electric (ME) which possess ideal properties of high drug loading, site-specificity and precise on-demand controlled drug delivery. Areas covered This review explores the potential of ME-NCs for on-demand and site-specific drug delivery and release for personalized therapeutics. The main features including effect of magnetism, improvement in drug loading, drug transport across blood-brain barriers and on-demand controlled release are also discussed. The future directions and possible impacts on upcoming nanomedicine are highlighted. Expert opinion Numerous reports suggest that there is an urgent need to explore novel NC formulations for safe and targeted drug delivery and release at specific disease sites. The challenges of formulation lie in the development of NCs that improve biocompatibility and surface modifications for optimum drug loading/preservation/transmigration and tailoring of electrical–magnetic properties for on-demand drug release. Thus, the development of novel NCs is anticipated to overcome the problems of targeted delivery of therapeutic agents with desired precision that may lead to better patient compliance. PMID:24986772

The potential of magneto-electric nanocarriers for drug delivery.

PubMed

Kaushik, Ajeet; Jayant, Rahul Dev; Sagar, Vidya; Nair, Madhavan

2014-10-01

The development and design of personalized nanomedicine for better health quality is receiving great attention. In order to deliver and release a therapeutic concentration at the target site, novel nanocarriers (NCs) were designed, for example, magneto-electric (ME) which possess ideal properties of high drug loading, site-specificity and precise on-demand controlled drug delivery. This review explores the potential of ME-NCs for on-demand and site-specific drug delivery and release for personalized therapeutics. The main features including effect of magnetism, improvement in drug loading, drug transport across blood-brain barriers and on-demand controlled release are also discussed. The future directions and possible impacts on upcoming nanomedicine are highlighted. Numerous reports suggest that there is an urgent need to explore novel NC formulations for safe and targeted drug delivery and release at specific disease sites. The challenges of formulation lie in the development of NCs that improve biocompatibility and surface modifications for optimum drug loading/preservation/transmigration and tailoring of electrical-magnetic properties for on-demand drug release. Thus, the development of novel NCs is anticipated to overcome the problems of targeted delivery of therapeutic agents with desired precision that may lead to better patient compliance.

Japanese Structure Survey of Radiation Oncology in 2005 Based on Institutional Stratification of Patterns of Care Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teshima, Teruki; Numasaki, Hodaka; Shibuya, Hitoshi

2008-09-01

Purpose: To evaluate the structure of radiation oncology in Japan in terms of equipment, personnel, patient load, and geographic distribution to identify and improve any deficiencies. Methods and Materials: A questionnaire-based national structure survey was conducted between March 2006 and February 2007 by the Japanese Society of Therapeutic Radiology and Oncology. These data were analyzed in terms of the institutional stratification of the Patterns of Care Study. Results: The total numbers of new cancer patients and total cancer patients (new and repeat) treated with radiotherapy in 2005 were estimated at approximately 162,000 and 198,000, respectively. In actual use were 765more » linear accelerators, 11 telecobalt machines, 48 GammaKnife machines, 64 {sup 60}Co remote-controlled after-loading systems, and 119 {sup 192}Ir remote-controlled after-loading systems. The linear accelerator systems used dual-energy function in 498 systems (65%), three-dimensional conformal radiotherapy in 462 (60%), and intensity-modulated radiotherapy in 170 (22%). There were 426 Japanese Society of Therapeutic Radiology and Oncology-certified radiation oncologists, 774 full-time equivalent radiation oncologists, 117 medical physicists, and 1,635 radiation therapists. Geographically, a significant variation was found in the use of radiotherapy, from 0.9 to 2.1 patients/1,000 population. The annual patient load/FTE radiation oncologist was 247, exceeding the Blue Book guidelines level. Patterns of Care Study stratification can clearly discriminate the maturity of structures according to their academic nature and caseload. Conclusions: The Japanese structure has clearly improved during the past 15 years in terms of equipment and its use, although the shortage of manpower and variations in maturity disclosed by this Patterns of Care Study stratification remain problematic. These constitute the targets for nationwide improvement in quality assurance and quality control.« less

A Sensorless Predictive Current Controlled Boost Converter by Using an EKF with Load Variation Effect Elimination Function

PubMed Central

Tong, Qiaoling; Chen, Chen; Zhang, Qiao; Zou, Xuecheng

2015-01-01

To realize accurate current control for a boost converter, a precise measurement of the inductor current is required to achieve high resolution current regulating. Current sensors are widely used to measure the inductor current. However, the current sensors and their processing circuits significantly contribute extra hardware cost, delay and noise to the system. They can also harm the system reliability. Therefore, current sensorless control techniques can bring cost effective and reliable solutions for various boost converter applications. According to the derived accurate model, which contains a number of parasitics, the boost converter is a nonlinear system. An Extended Kalman Filter (EKF) is proposed for inductor current estimation and output voltage filtering. With this approach, the system can have the same advantages as sensored current control mode. To implement EKF, the load value is necessary. However, the load may vary from time to time. This can lead to errors of current estimation and filtered output voltage. To solve this issue, a load variation elimination effect elimination (LVEE) module is added. In addition, a predictive average current controller is used to regulate the current. Compared with conventional voltage controlled system, the transient response is greatly improved since it only takes two switching cycles for the current to reach its reference. Finally, experimental results are presented to verify the stable operation and output tracking capability for large-signal transients of the proposed algorithm. PMID:25928061

Comparative study of reference currents and DC bus voltage control for Three-Phase Four-Wire Four-Leg SAPF to compensate harmonics and reactive power with 3D SVM.

PubMed

Chebabhi, A; Fellah, M K; Kessal, A; Benkhoris, M F

2015-07-01

In this paper the performances of three reference currents and DC bus voltage control techniques for Three-Phase Four-Wire Four-Leg SAPF are compared for balanced and unbalanced load conditions. The main goals are to minimize the harmonics, reduce the magnitude of neutral current, eliminate the zero-sequence current components caused by single-phase nonlinear loads and compensate the reactive power, and on the other hand improve performances such as robustness, stabilization, trajectory pursuit, and reduce time response. The three techniques are analyzed mathematically and simulation results are compared. The techniques considered for comparative study are the PI Control, Sliding Mode Control and the Backstepping Control. Synchronous reference frame theory (SRF) in the dqo-axes is used to generate the reference currents, of the inverter. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Method of controlling switching of a multiphase inductor-converter bridge

DOEpatents

Kustom, Robert L.; Fuja, Raymond E.

1981-01-01

In an inductor-convertor circuit for transferring electrical energy between a storage coil and a load coil using a storage thyristor bridge, a load thyristor bridge, and a set of commutating capacitors, operation is improved by a method of changing the rate of delivery of energy in a given direction. The change in rate corresponds to a predetermined change in phase angle between the load bridge and the storage bridge and comprises changing the phase of the bridge by two steps, each equal to half the predetermined change and occurring 180.degree. apart. The method assures commutation and minimizes imbalances that lead otherwise to overvoltages.

Control-release microcapsule of famotidine loaded biomimetic synthesized mesoporous silica nanoparticles: Controlled release effect and enhanced stomach adhesion in vitro.

PubMed

Li, Jing; Wang, Hongyu; Yang, Baixue; Xu, Lu; Zheng, Nan; Chen, Hongtao; Li, Sanming

2016-01-01

In the present work, control-release microcapsule of famotidine (FMT) loaded biomimetic synthesized mesoporous silica nanoparticles (B-MSNs) was developed, and controlled release effect and stomach adhesion of this formulation in vitro were mainly investigated. B-MSN was previously synthesized and it was amorphous mesoporous nanoparticles with helical channels. Cytotoxicity of B-MSN was studied using human breast cancer cells (MCF-7) and the result indicated that cytotoxicity of B-MSN can be neglected. After loading FMT into B-MSN, specific surface area, pore volume and pore diameter of B-MSN were obviously reduced. In vitro dissolution test showed that B-MSN had the ability to slow down FMT release for 15 min. In order to prolong controlled release effect and remained the advantage of B-MSN (improve drug stability due to its rigid silica framework), the combined application of control-release microcapsule (using cellulose and hydroxypropyl methylcellulose K15M as excipients) with B-MSN was designed. It was obvious that newly designed formulation significantly controlled FMT release with Fickian diffusion mechanism and showed enhanced stomach adhesion in vitro, which has significant value in widening the application of B-MSN in formulation design. Copyright © 2015 Elsevier B.V. All rights reserved.

Improved Speed Control System for the 87,000 HP Wind Tunnel Drive

NASA Technical Reports Server (NTRS)

Becks, Edward A.; Bencic, Timothy J.; Blumenthal, Philip Z.

1995-01-01

This paper describes the design, installation, and integrated systems tests for a new drive motor speed control system which was part of a recent rehab project for the NASA Lewis 8x6 Supersonic Wind Tunnel. The tunnel drive consists of three mechanically-coupled 29,000 HP wound rotor induction motors driving an axial flow compressor. Liquid rheostats are used to vary the impedance of the rotor circuits, thus varying the speed of the drive system. The new design utilizes a distributed digital control system with a dual touch screen CRT operator console to provide alarm monitoring, logging, and trending. The liquid rheostats are driven by brushtype servomotor systems with magnetostrictive linear displacement transducers used for position feedback. The new system achieved all goals for speed variations with load, motor load balance, and control of total power.

Improved speed control system for the 87,000 HP wind tunnel drive

NASA Astrophysics Data System (ADS)

Becks, Edward A.; Bencic, Timothy J.; Blumenthal, Philip Z.

1995-01-01

This paper describes the design, installation, and integrated systems tests for a new drive motor speed control system which was part of a recent rehab project for the NASA Lewis 8x6 Supersonic Wind Tunnel. The tunnel drive consists of three mechanically-coupled 29,000 HP wound rotor induction motors driving an axial flow compressor. Liquid rheostats are used to vary the impedance of the rotor circuits, thus varying the speed of the drive system. The new design utilizes a distributed digital control system with a dual touch screen CRT operator console to provide alarm monitoring, logging, and trending. The liquid rheostats are driven by brushtype servomotor systems with magnetostrictive linear displacement transducers used for position feedback. The new system achieved all goals for speed variations with load, motor load balance, and control of total power.

Gait and balance of transfemoral amputees using passive mechanical and microprocessor-controlled prosthetic knees.

PubMed

Kaufman, K R; Levine, J A; Brey, R H; Iverson, B K; McCrady, S K; Padgett, D J; Joyner, M J

2007-10-01

Microprocessor-controlled knee joints appeared on the market a decade ago. These joints are more sophisticated and more expensive than mechanical ones. The literature is contradictory regarding changes in gait and balance when using these sophisticated devices. This study employed a crossover design to assess the comparative performance of a passive mechanical knee prosthesis compared to a microprocessor-controlled knee joint in 15 subjects with an above-knee amputation. Objective measurements of gait and balance were obtained. Subjects demonstrated significantly improved gait characteristics after receiving the microprocessor-controlled prosthetic knee joint (p<0.01). Improvements in gait were a transition from a hyperextended knee to a flexed knee during loading response which resulted in a change from an internal knee flexor moment to a knee extensor moment. The participants' balance also improved (p<0.01). All conditions of the Sensory Organization Test (SOT) demonstrated improvements in equilibrium score. The composite score also increased. Transfemoral amputees using a microprocessor-controlled knee have significant improvements in gait and balance.

Opportunities for Energy Efficiency and Automated Demand Response in Industrial Refrigerated Warehouses in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lekov, Alex; Thompson, Lisa; McKane, Aimee

2009-05-11

This report summarizes the Lawrence Berkeley National Laboratory's research to date in characterizing energy efficiency and open automated demand response opportunities for industrial refrigerated warehouses in California. The report describes refrigerated warehouses characteristics, energy use and demand, and control systems. It also discusses energy efficiency and open automated demand response opportunities and provides analysis results from three demand response studies. In addition, several energy efficiency, load management, and demand response case studies are provided for refrigerated warehouses. This study shows that refrigerated warehouses can be excellent candidates for open automated demand response and that facilities which have implemented energy efficiencymore » measures and have centralized control systems are well-suited to shift or shed electrical loads in response to financial incentives, utility bill savings, and/or opportunities to enhance reliability of service. Control technologies installed for energy efficiency and load management purposes can often be adapted for open automated demand response (OpenADR) at little additional cost. These improved controls may prepare facilities to be more receptive to OpenADR due to both increased confidence in the opportunities for controlling energy cost/use and access to the real-time data.« less

Latex improvement of recycled asphalt pavement

NASA Astrophysics Data System (ADS)

Drennon, C.

1982-08-01

The performance of a single unmodified milled recycled asphalt concrete was compared to milled asphalt concrete modified by addition of three types of rubber latex. Latex was added at 2, 3, 5, and 8 percent latex by weight of asphalt in the asphalt concrete. Lattices used were a styrene butadiene (SBR), a natural rubber (NR), an acrylonitrile butadiene (NBR), and four varieties of out of specification SBR lattices. Marshall tests, while indecisive, showed a modest improvement in properties of SBR and NR added material at 3 and 5 percent latex. Addition of NBR latex caused deterioration in Marshall stability and flow over that of control. Repeated load tests were run using the indirect tensile test, analyzed by the VESYS program, which computes life of pavements. Repeated load tests showed improvement in asphalt concrete life when 3 and 5 percent SBR was added. Improvement was also shown by the out of specification SBR.

Dispersible shortened boron nitride nanotubes with improved molecule-loading capacity.

PubMed

Zhi, Chunyi; Hanagata, Nobutaka; Bando, Yoshio; Golberg, Dmitri

2011-09-05

The oxidation process of boron nitride nanotubes was thoroughly investigated, and a slow oxidation characteristic was clearly revealed. Subsequently, the controllable oxidation process was utilized to break the sturdy structure of the boron nitride nanotubes to fabricate shortened nanotubes. The shortened boron nitride nanotubes were found to possess good solubility in water and many organic solvents. Further experiments demonstrated remarkably improved molecule-loading capacity of the shortened boron nitride nanotubes. These dispersible shortened boron nitride nanotubes might have the potential to be developed as effective delivery systems for various molecules, which may find applications in bio-related fields. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Optimal Current Controller Design for a Grid Connected Inverter to Improve Power Quality and Test Commercial PV Inverters.

PubMed

Algaddafi, Ali; Altuwayjiri, Saud A; Ahmed, Oday A; Daho, Ibrahim

2017-01-01

Grid connected inverters play a crucial role in generating energy to be fed to the grid. A filter is commonly used to suppress the switching frequency harmonics produced by the inverter, this being passive, and either an L- or LCL-filter. The latter is smaller in size compared to the L-filter. But choosing the optimal values of the LCL-filter is challenging due to resonance, which can affect stability. This paper presents a simple inverter controller design with an L-filter. The control topology is simple and applied easily using traditional control theory. Fast Fourier Transform analysis is used to compare different grid connected inverter control topologies. The modelled grid connected inverter with the proposed controller complies with the IEEE-1547 standard, and total harmonic distortion of the output current of the modelled inverter has been just 0.25% with an improved output waveform. Experimental work on a commercial PV inverter is then presented, including the effect of strong and weak grid connection. Inverter effects on the resistive load connected at the point of common coupling are presented. Results show that the voltage and current of resistive load, when the grid is interrupted, are increased, which may cause failure or damage for connecting appliances.

An Optimal Current Controller Design for a Grid Connected Inverter to Improve Power Quality and Test Commercial PV Inverters

PubMed Central

Altuwayjiri, Saud A.; Ahmed, Oday A.; Daho, Ibrahim

2017-01-01

Grid connected inverters play a crucial role in generating energy to be fed to the grid. A filter is commonly used to suppress the switching frequency harmonics produced by the inverter, this being passive, and either an L- or LCL-filter. The latter is smaller in size compared to the L-filter. But choosing the optimal values of the LCL-filter is challenging due to resonance, which can affect stability. This paper presents a simple inverter controller design with an L-filter. The control topology is simple and applied easily using traditional control theory. Fast Fourier Transform analysis is used to compare different grid connected inverter control topologies. The modelled grid connected inverter with the proposed controller complies with the IEEE-1547 standard, and total harmonic distortion of the output current of the modelled inverter has been just 0.25% with an improved output waveform. Experimental work on a commercial PV inverter is then presented, including the effect of strong and weak grid connection. Inverter effects on the resistive load connected at the point of common coupling are presented. Results show that the voltage and current of resistive load, when the grid is interrupted, are increased, which may cause failure or damage for connecting appliances. PMID:28540362

Nicotine effects on brain function and functional connectivity in schizophrenia.

PubMed

Jacobsen, Leslie K; D'Souza, D Cyril; Mencl, W Einar; Pugh, Kenneth R; Skudlarski, Pawel; Krystal, John H

2004-04-15

Nicotine in tobacco smoke can improve functioning in multiple cognitive domains. High rates of smoking among schizophrenic patients may reflect an effort to remediate cognitive dysfunction. Our primary aim was to determine whether nicotine improves cognitive function by facilitating activation of brain regions mediating task performance or by facilitating functional connectivity. Thirteen smokers with schizophrenia and 13 smokers with no mental illness were withdrawn from tobacco and underwent functional magnetic resonance imaging (fMRI) scanning twice, once after placement of a placebo patch and once after placement of a nicotine patch. During scanning, subjects performed an n-back task with two levels of working memory load and of selective attention load. During the most difficult (dichotic 2-back) task condition, nicotine improved performance of schizophrenic subjects and worsened performance of control subjects. Nicotine also enhanced activation of a network of regions, including anterior cingulate cortex and bilateral thalamus, and modulated thalamocortical functional connectivity to a greater degree in schizophrenic than in control subjects during dichotic 2-back task performance. In tasks that tax working memory and selective attention, nicotine may improve performance in schizophrenia patients by enhancing activation of and functional connectivity between brain regions that mediate task performance.

Chitosan-based nano-in-microparticle carriers for enhanced oral delivery and anticancer activity of propolis.

PubMed

Elbaz, Nancy M; Khalil, Islam A; Abd-Rabou, Ahmed A; El-Sherbiny, Ibrahim M

2016-11-01

This study reports a promising approach to enhance the oral delivery of propolis, improve its aqueous solubility and bioavailability, and allow its controlled release as well as enhancing its anticancer activity. Propolis was standardized then its solubility was improved via formulation into optimized solid dispersion (SD) matrices, and its release was controlled through incorporation into nanoparticles (NPs) of optimized composition followed by further inclusion into chitosan (Cs) microparticles. The anticancer activity of the newly developed propolis-loaded nano-in-microparticles (NIMs) was evaluated against human liver cancer (HepG2) and human colorectal cancer (HCT 116) cells. The prepared SDs, NPs and NIMs were characterized using SEM, TEM, DLS, FTIR, DSC and UV-vis spectrophotometry. The therapeutic efficiency of formulated propolis was bio-assessed via cytotoxicity measurements, mitochondrial dysfunction, apoptosis-induced cell death and cell cycle arrest. The results demonstrated a considerable enhancement in propolis solubility with a controlled release profile in different GIT environments. In-vitro cytotoxicity studies showed that the propolis-loaded NIMs induce more cytotoxic effect on HepG2 cells than HCT-116 cells and mediated three-fold higher therapeutic efficiency than free propolis. The apoptosis assay indicated that the propolis-loaded NIMs induce apoptosis of HepG2 cells and significantly decrease their number in the proliferative G0/G1, S and G2/M phases. Copyright © 2016 Elsevier B.V. All rights reserved.

Load controller and method to enhance effective capacity of a photovoltaic power supply

DOEpatents

Perez, Richard

2000-01-01

A load controller and method are provided for maximizing effective capacity of a non-controllable, renewable power supply coupled to a variable electrical load also coupled to a conventional power grid. Effective capacity is enhanced by monitoring power output of the renewable supply and loading, and comparing the loading against the power output and a load adjustment threshold determined from an expected peak loading. A value for a load adjustment parameter is calculated by subtracting the renewable supply output and the load adjustment parameter from the current load. This value is then employed to control the variable load in an amount proportional to the value of the load control parameter when the parameter is within a predefined range. By so controlling the load, the effective capacity of the non-controllable, renewable power supply is increased without any attempt at operational feedback control of the renewable supply. The renewable supply may comprise, for example, a photovoltaic power supply or a wind-based power supply.

Dual fuel gradients in uranium silicide plates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pace, B.W.

1997-08-01

Babcock & Wilcox has been able to achieve dual gradient plates with good repeatability in small lots of U{sub 3}Si{sub 2} plates. Improvements in homogeneity and other processing parameters and techniques have allowed the development of contoured fuel within the cladding. The most difficult obstacles to overcome have been the ability to evaluate the bidirectional fuel loadings in comparison to the perfect loading model and the different methods of instilling the gradients in the early compact stage. The overriding conclusion is that to control the contour of the fuel, a known relationship between the compact, the frames and final coremore » gradient must exist. Therefore, further development in the creation and control of dual gradients in fuel plates will involve arriving at a plausible gradient requirement and building the correct model between the compact configuration and the final contoured loading requirements.« less

Bactericidal Activity of Usnic Acid-Loaded Electrospun Fibers.

PubMed

Araújo, Evando S; Pereira, Eugênia C; da Costa, Mateus M; da Silva, Nicácio H; de Oliveira, Helinando P

2016-01-01

Usnic acid has been progressively reported in the literature as one of the most important lichen metabolites characterized by a rich diversity of applications such as antifungal, antimicrobial, antiprotozoal and antiviral agent. Particularly, antimicrobial activity of usnic acid can be improved by encapsulation of active molecules in enteric electrospun fibers, allowing the controlled release of active molecule at specific pH. Few relevant patents to the topic have been reviewed and cited. Bactericidal activity of usnic acid-loaded electrospun fibers of Eudragit L-100 and polyvinylpyrrolidone was examined against Staphylococcus aureus using inhibition hales methodology. The controlled release of active material at high pH is established after 10 minutes of interaction with media and results in reasonable activity against S. aureus, as detected by inhibition hales. The strong biological activity of usnic acid-loaded electrospun fibers provides a promising application for corresponding material as a bactericidal agent for wound healing treatment.

Robotic Resistance Treadmill Training Improves Locomotor Function in Children With Cerebral Palsy: A Randomized Controlled Pilot Study.

PubMed

Wu, Ming; Kim, Janis; Gaebler-Spira, Deborah J; Schmit, Brian D; Arora, Pooja

2017-11-01

To determine whether applying controlled resistance forces to the legs during the swing phase of gait may improve the efficacy of treadmill training as compared with applying controlled assistance forces in children with cerebral palsy (CP). Randomized controlled study. Research unit of a rehabilitation hospital. Children with spastic CP (N=23; mean age, 10.6y; range, 6-14y; Gross Motor Function Classification System levels, I-IV). Participants were randomly assigned to receive controlled assistance (n=11) or resistance (n=12) loads applied to the legs at the ankle. Participants underwent robotic treadmill training 3 times a week for 6 weeks (18 sessions). A controlled swing assistance/resistance load was applied to both legs starting from the toe-off to mid-swing phase of gait during training. Outcome measures consisted of overground walking speed, 6-minute walk distance, and Gross Motor Function Measure scores and were assessed pre and post 6 weeks of training and 8 weeks after the end of training. After 6 weeks of treadmill training in participants from the resistance training group, fast walking speed and 6-minute walk distance significantly improved (18% and 30% increases, respectively), and 6-minute walk distance was still significantly greater than that at baseline (35% increase) 8 weeks after the end of training. In contrast, overground gait speed and 6-minute walk distance had no significant changes after robotic assistance training. The results of the present study indicated that robotic resistance treadmill training is more effective than assistance training in improving locomotor function in children with CP. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Load sharing in bioinspired fibrillar adhesives with backing layer interactions and interfacial misalignment

NASA Astrophysics Data System (ADS)

Bacca, Mattia; Booth, Jamie A.; Turner, Kimberly L.; McMeeking, Robert M.

2016-11-01

Bio-inspired fibrillar adhesives rely on the utilization of short-range intermolecular forces harnessed by intimate contact at fibril tips. The combined adhesive strength of multiple fibrils can only be utilized if equal load sharing (ELS) is obtained at detachment. Previous investigations have highlighted that mechanical coupling of fibrils through a compliant backing layer gives rise to load concentration and the nucleation and propagation of interfacial flaws. However, misalignment of the adhesive and contacting surface has not been considered in theoretical treatments of load sharing with backing layer interactions. Alignment imperfections are difficult to avoid for a flat-on-flat interfacial configuration. In this work we demonstrate that interfacial misalignment can significantly alter load sharing and the kinematics of detachment in a model adhesive system. Load sharing regimes dominated by backing layer interactions and misalignment are revealed, the transition between which is controlled by the misalignment angle, fibril separation, and fibril compliance. In the regime dominated by misalignment, backing layer deformation can counteract misalignment giving rise to improved load sharing when compared to an identical fibrillar array with a rigid backing layer. This result challenges the conventional belief that stiffer (and thinner) backing layers consistently reduce load concentration among fibrils. Finally, we obtain analytically the fibril compliance distribution required to harness backing layer interactions to obtain ELS. Through fibril compliance optimization, ELS can be obtained even with misalignment. However, since misalignment is typically not deterministic, it is of greater practical significance that the array optimized for perfect alignment exhibits load sharing superior to that of a homogeneous array subject to misalignment. These results inform the design of fibrillar arrays with graded compliance capable of exhibiting improved load sharing over large areas.

Guidance and control/ACEE

NASA Technical Reports Server (NTRS)

1981-01-01

Active controls improve airplane performance by stabilizing its flight, reducing departures from stable flight, and alleviating loads imposed by external forces such as gusts, turbulence, or maneuvers. Some uses for active control systems, the design of redundant and reliable stability augmentation systems, digital fly-by-wire, and NASA assessments of the technology of sensors and actuators are discussed. A series of trade-off studies to better define optimum flight control systems, and research by drone and full-scale models are described.

An evaluation of retrofit engineering control interventions to reduce perchloroethylene exposures in commercial dry-cleaning shops.

PubMed

Earnest, G Scott; Ewers, Lynda M; Ruder, Avima M; Petersen, Martin R; Kovein, Ronald J

2002-02-01

Real-time monitoring was used to evaluate the ability of engineering control devices retrofitted on two existing dry-cleaning machines to reduce worker exposures to perchloroethylene. In one dry-cleaning shop, a refrigerated condenser was installed on a machine that had a water-cooled condenser to reduce the air temperature, improve vapor recovery, and lower exposures. In a second shop, a carbon adsorber was retrofitted on a machine to adsorb residual perchloroethylene not collected by the existing refrigerated condenser to improve vapor recovery and reduce exposures. Both controls were successful at reducing the perchloroethylene exposures of the dry-cleaning machine operator. Real-time monitoring was performed to evaluate how the engineering controls affected exposures during loading and unloading the dry-cleaning machine, a task generally considered to account for the highest exposures. The real-time monitoring showed that dramatic reductions occurred in exposures during loading and unloading of the dry-cleaning machine due to the engineering controls. Peak operator exposures during loading and unloading were reduced by 60 percent in the shop that had a refrigerated condenser installed on the dry-cleaning machine and 92 percent in the shop that had a carbon adsorber installed. Although loading and unloading exposures were dramatically reduced, drops in full-shift time-weighted average (TWA) exposures were less dramatic. TWA exposures to perchloroethylene, as measured by conventional air sampling, showed smaller reductions in operator exposures of 28 percent or less. Differences between exposure results from real-time and conventional air sampling very likely resulted from other uncontrolled sources of exposure, differences in shop general ventilation before and after the control was installed, relatively small sample sizes, and experimental variability inherent in field research. Although there were some difficulties and complications with installation and maintenance of the engineering controls, this study showed that retrofitting engineering controls may be a feasible option for some dry-cleaning shop owners to reduce worker exposures to perchloroethylene. By installing retrofit controls, a dry-cleaning facility can reduce exposures, in some cases dramatically, and bring operators into compliance with the Occupational Safety and Health Administration (OSHA) peak exposure limit of 300 ppm. Retrofit engineering controls are also likely to enable many dry-cleaning workers to lower their overall personal TWA exposures to perchloroethylene.

Improved memory loading techniques for the TSRV display system

NASA Technical Reports Server (NTRS)

Easley, W. C.; Lynn, W. A.; Mcluer, D. G.

1986-01-01

A recent upgrade of the TSRV research flight system at NASA Langley Research Center retained the original monochrome display system. However, the display memory loading equipment was replaced requiring design and development of new methods of performing this task. This paper describes the new techniques developed to load memory in the display system. An outdated paper tape method for loading the BOOTSTRAP control program was replaced by EPROM storage of the characters contained on the tape. Rather than move a tape past an optical reader, a counter was implemented which steps sequentially through EPROM addresses and presents the same data to the loader circuitry. A cumbersome cassette tape method for loading the applications software was replaced with a floppy disk method using a microprocessor terminal installed as part of the upgrade. The cassette memory image was transferred to disk and a specific software loader was written for the terminal which duplicates the function of the cassette loader.

A three degree of freedom manipulator used for store separation wind tunnel test

NASA Astrophysics Data System (ADS)

Wei, R.; Che, B.-H.; Sun, C.-B.; Zhang, J.; Lu, Y.-Q.

2018-06-01

A three degree of freedom manipulator is presented, which is used for store separation wind tunnel test. It is a kind of mechatronics product, have small volume and large moment of torque. The paper researched the design principle of wind tunnel test equipment, also introduced the transmission principle design, physical design, control system design, drive element selection calculation and verification, dynamics computation and static structural computation of the manipulator. To satisfy the design principle of wind tunnel test equipment, some optimization design are made include optimizes the structure of drive element and cable, fairing configuration, overall dimension so that to make the device more suitable for the wind tunnel test. Some tests are made to verify the parameters of the manipulator. The results show that the device improves the load from 100 Nm to 250 Nm, control accuracy from 0.1°to 0.05°in pitch and yaw, also improves load from 10 Nm to 20 Nm, control accuracy from 0.1°to 0.05°in roll.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magee, Thoman

The Consolidated Edison, Inc., of New York (Con Edison) Secure Interoperable Open Smart Grid Demonstration Project (SGDP), sponsored by the United States (US) Department of Energy (DOE), demonstrated that the reliability, efficiency, and flexibility of the grid can be improved through a combination of enhanced monitoring and control capabilities using systems and resources that interoperate within a secure services framework. The project demonstrated the capability to shift, balance, and reduce load where and when needed in response to system contingencies or emergencies by leveraging controllable field assets. The range of field assets includes curtailable customer loads, distributed generation (DG), batterymore » storage, electric vehicle (EV) charging stations, building management systems (BMS), home area networks (HANs), high-voltage monitoring, and advanced metering infrastructure (AMI). The SGDP enables the seamless integration and control of these field assets through a common, cyber-secure, interoperable control platform, which integrates a number of existing legacy control and data systems, as well as new smart grid (SG) systems and applications. By integrating advanced technologies for monitoring and control, the SGDP helps target and reduce peak load growth, improves the reliability and efficiency of Con Edison’s grid, and increases the ability to accommodate the growing use of distributed resources. Con Edison is dedicated to lowering costs, improving reliability and customer service, and reducing its impact on the environment for its customers. These objectives also align with the policy objectives of New York State as a whole. To help meet these objectives, Con Edison’s long-term vision for the distribution grid relies on the successful integration and control of a growing penetration of distributed resources, including demand response (DR) resources, battery storage units, and DG. For example, Con Edison is expecting significant long-term growth of DG. The SGDP enables the efficient, flexible integration of these disparate resources and lays the architectural foundations for future scalability. Con Edison assembled an SGDP team of more than 16 different project partners, including technology vendors, and participating organizations, and the Con Edison team provided overall guidance and project management. Project team members are listed in Table 1-1.« less

Selected advanced aerodynamics and active controls technology concepts development on a derivative B-747 aircraft

NASA Technical Reports Server (NTRS)

1983-01-01

Analytical design and wind tunnel test evaluations covering the feasibility of applying wing tip extensions, winglets, and active control wing had alleviation to the model B747 are described. Aerodynamic improvement offered by wing tip extension and winglet individually, and the combined aerodynamic and weight improvements when wing load alleviation is combined with the tip extension or the winglet are evaluated. Results are presented in the form of incremental effects on weight mission range, fuel usage, cost, and airline operating economics.

Aggregate Load Controllers and Associated Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chassin, David P.

Aggregate load controllers and associated methods are described. According to one aspect, a method of operating an aggregate load controller includes using an aggregate load controller having an initial state, applying a stimulus to a plurality of thermostatic controllers which are configured to control a plurality of respective thermostatic loads which receive electrical energy from an electrical utility to operate in a plurality of different operational modes, accessing data regarding a response of the thermostatic loads as a result of the applied stimulus, using the data regarding the response, determining a value of at least one design parameter of themore » aggregate load controller, and using the determined value of the at least one design parameter, configuring the aggregate load controller to control amounts of the electrical energy which are utilized by the thermostatic loads.« less

Buoyancy-corrected gravimetric analysis of lightly loaded filters.

PubMed

Rasmussen, Pat E; Gardner, H David; Niu, Jianjun

2010-09-01

Numerous sources of uncertainty are associated with the gravimetric analysis of lightly loaded air filter samples (< 100 microg). The purpose of the study presented here is to investigate the effectiveness and limitations of air buoyancy corrections over experimentally adjusted conditions of temperature (21-25 degrees C) and relative humidity (RH) (16-60% RH). Conditioning (24 hr) and weighing were performed inside the Archimedes M3 environmentally controlled chamber. The measurements were performed using 20 size-fractionated samples of resuspended house dust loaded onto Teflo (PTFE) filters using a Micro-Orifice Uniform Deposit Impactor representing a wide range of mass loading (7.2-3130 microg) and cut sizes (0.056-9.9 microm). By maintaining tight controls on humidity (within 0.5% RH of control setting) throughout pre- and postweighing at each stepwise increase in RH, it was possible to quantify error due to water absorption: 45% of the total mass change due to water absorption occurred between 16 and 50% RH, and 55% occurred between 50 and 60% RH. The buoyancy corrections ranged from -3.5 to +5.8 microg in magnitude and improved relative standard deviation (RSD) from 21.3% (uncorrected) to 5.6% (corrected) for a 7.2 microg sample. It is recommended that protocols for weighing low-mass particle samples (e.g., nanoparticle samples) should include buoyancy corrections and tight temperature/humidity controls. In some cases, conditioning times longer than 24 hr may be warranted.

An active homopolar magnetic bearing with high temperature superconductor (HTS) coils and ferromagnetic cores

NASA Technical Reports Server (NTRS)

Brown, G. V.; Dirusso, E.; Provenza, A. J.

1995-01-01

A proof-of-feasibility demonstration showed that high temperature superconductor (HTS) coils can be used in a high-load, active magnetic bearing in liquid nitrogen. A homopolar radial bearing with commercially wound HTS (Bi 2223) bias and control coils produced over 200 lb (890 N) radial load capacity (measured non-rotating) and supported a shaft to 14000 rpm. The goal was to show that HTS coils can operate stably with ferromagnetic cores in a feedback controlled system at a current density similar to that in Cu in liquid nitrogen. Design compromises permitted use of circular coils with rectangular cross section. Conductor improvements will eventually permit coil shape optimization, higher current density and higher bearing load capacity. The bias coil, wound with non-twisted, multifilament HTS conductor, required negligible power to carry its direct current. The control coils were wound with monofilament HTS sheathed in Ag. These dissipated negligible power for direct current (i.e. for steady radial load components). When an alternating current (AC) was added, the AC component dissipated power which increased rapidly with frequency and quadratically with AC amplitude. In fact at frequencies above about 2 hz, the effective resistance of the control coil conductor actually exceeds that of the silver which is in electrical parallel with the oxide superconductor. This is at least qualitatively understandable in the context of a Bean-type model of flux and current penetration into a Type II superconductor. Fortunately the dynamic currents required for bearing stability are of small amplitude. These results show that while twisted multifilament conductor is not needed for stable levitation, twisted multifilaments will be required to reduce control power for sizable dynamic loads, such as those due to unbalance.

Model-centric distribution automation: Capacity, reliability, and efficiency

DOE PAGES

Onen, Ahmet; Jung, Jaesung; Dilek, Murat; ...

2016-02-26

A series of analyses along with field validations that evaluate efficiency, reliability, and capacity improvements of model-centric distribution automation are presented. With model-centric distribution automation, the same model is used from design to real-time control calculations. A 14-feeder system with 7 substations is considered. The analyses involve hourly time-varying loads and annual load growth factors. Phase balancing and capacitor redesign modifications are used to better prepare the system for distribution automation, where the designs are performed considering time-varying loads. Coordinated control of load tap changing transformers, line regulators, and switched capacitor banks is considered. In evaluating distribution automation versus traditionalmore » system design and operation, quasi-steady-state power flow analysis is used. In evaluating distribution automation performance for substation transformer failures, reconfiguration for restoration analysis is performed. In evaluating distribution automation for storm conditions, Monte Carlo simulations coupled with reconfiguration for restoration calculations are used. As a result, the evaluations demonstrate that model-centric distribution automation has positive effects on system efficiency, capacity, and reliability.« less

Field Experience with and Potential for Multi-time Scale Grid Transactions from Responsive Commercial Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Piette, Mary Ann; Kiliccote, Sila; Ghatikar, Girish

2014-08-01

The need for and concepts behind demand response are evolving. As the electric system changes with more intermittent renewable electric supply systems, there is a need to allow buildings to provide more flexible demand. This paper presents results from field studies and pilots, as well as engineering estimates of the potential capabilities of fast load responsiveness in commercial buildings. We present a sector wide analysis of flexible loads in commercial buildings, which was conducted to improve resource planning and determine which loads to evaluate in future demonstrations. These systems provide important capabilities for future transactional systems. The field analysis ismore » based on results from California, plus projects in the northwest and east coast. End-uses considered include heating, ventilation, air conditioning and lighting. The timescales of control include day-ahead, as well as day-of, 10-minute ahead and even faster response. This technology can provide DR signals on different times scales to interact with responsive building loads. We describe the latency of the control systems in the building and the round trip communications with the wholesale grid operators.« less

Model-centric distribution automation: Capacity, reliability, and efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onen, Ahmet; Jung, Jaesung; Dilek, Murat

A series of analyses along with field validations that evaluate efficiency, reliability, and capacity improvements of model-centric distribution automation are presented. With model-centric distribution automation, the same model is used from design to real-time control calculations. A 14-feeder system with 7 substations is considered. The analyses involve hourly time-varying loads and annual load growth factors. Phase balancing and capacitor redesign modifications are used to better prepare the system for distribution automation, where the designs are performed considering time-varying loads. Coordinated control of load tap changing transformers, line regulators, and switched capacitor banks is considered. In evaluating distribution automation versus traditionalmore » system design and operation, quasi-steady-state power flow analysis is used. In evaluating distribution automation performance for substation transformer failures, reconfiguration for restoration analysis is performed. In evaluating distribution automation for storm conditions, Monte Carlo simulations coupled with reconfiguration for restoration calculations are used. As a result, the evaluations demonstrate that model-centric distribution automation has positive effects on system efficiency, capacity, and reliability.« less

A Peer-Led HIV Mediation Adherence Intervention Targeting Adults Linked to Medical Care but without a Suppressed Viral Load

PubMed Central

Enriquez, Maithe; Cheng, An-Lin; Banderas, Julie; Farnan, Rose; Chertoff, Keyna; Hayes, Deana; Ortego, Gerry; Moreno, Jose; Peterson, Jane; McKinsey, David

2017-01-01

Background Non-adherence to antiretroviral (ART) treatment remains a prevalent problem even among the segment of the U.S. HIV population that is ‘linked’ to medical care. Methods Controlled pilot feasibility study with ART experienced adult patients (n=20) linked to HIV medical care without suppressed viral load. Patients were randomized to a peer-led HIV medication adherence intervention named ‘Ready’ or a time equivalent ‘healthy eating’ control arm. Lay individuals living with HIV were trained to facilitate ‘Ready’. Results Patients had been prescribed a mean of three prior ART regimens. The group randomized to ‘Ready’ had significantly improved adherence. MEMS and pharmacy refill data correlated with viral load log drop. Higher readiness for healthful behavior change correlated with viral load drop and approached significance. Conclusion A peer-led medication adherence intervention had a positive impact among adults who had experienced repeated non-adherence to HIV treatment. A larger study is needed to examine intervention dissemination and efficacy. PMID:25412724

Total maximum allocated load calculation of nitrogen pollutants by linking a 3D biogeochemical-hydrodynamic model with a programming model in Bohai Sea

NASA Astrophysics Data System (ADS)

Dai, Aiquan; Li, Keqiang; Ding, Dongsheng; Li, Yan; Liang, Shengkang; Li, Yanbin; Su, Ying; Wang, Xiulin

2015-12-01

The equal percent removal (EPR) method, in which pollutant reduction ratio was set as the same in all administrative regions, failed to satisfy the requirement for water quality improvement in the Bohai Sea. Such requirement was imposed by the developed Coastal Pollution Total Load Control Management. The total maximum allocated load (TMAL) of nitrogen pollutants in the sea-sink source regions (SSRs) around the Bohai Rim, which is the maximum pollutant load of every outlet under the limitation of water quality criteria, was estimated by optimization-simulation method (OSM) combined with loop approximation calculation. In OSM, water quality is simulated using a water quality model and pollutant load is calculated with a programming model. The effect of changes in pollutant loads on TMAL was discussed. Results showed that the TMAL of nitrogen pollutants in 34 SSRs was 1.49×105 ton/year. The highest TMAL was observed in summer, whereas the lowest in winter. TMAL was also higher in the Bohai Strait and central Bohai Sea and lower in the inner area of the Liaodong Bay, Bohai Bay and Laizhou Bay. In loop approximation calculation, the TMAL obtained was considered satisfactory for water quality criteria as fluctuation of concentration response matrix with pollutant loads was eliminated. Results of numerical experiment further showed that water quality improved faster and were more evident under TMAL input than that when using the EPR method

Synthesis and evaluation of mesoporous carbon/lipid bilayer nanocomposites for improved oral delivery of the poorly water-soluble drug, nimodipine.

PubMed

Zhang, Yanzhuo; Zhao, Qinfu; Zhu, Wufu; Zhang, Lihua; Han, Jin; Lin, Qisi; Ai, Fengwei

2015-07-01

A novel mesoporous carbon/lipid bilayer nanocomposite (MCLN) with a core-shell structure was synthesized and characterized as an oral drug delivery system for poorly water-soluble drugs. The objective of this study was to investigate the potential of MCLN-based formulation to modulate the in vitro release and in vivo absorption of a model drug, nimodipine (NIM). NIM-loaded MCLN was prepared by a procedure involving a combination of thin-film hydration and lyophilization. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area analysis, differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were employed to characterize the NIM-loaded MCLN formulation. The effect of MCLN on cell viability was assessed using the MTT assay. In addition, the oral bioavailability of NIM-loaded MCLN in beagle dogs was compared with that of the immediate-release formulation, Nimotop®. Our results demonstrate that the NIM-loaded MCLN formulation exhibited a typical sustained release pattern. The NIM-loaded MCLN formulation achieved a greater degree of absorption and longer lasting plasma drug levels compared with the commercial formulation. The relative bioavailability of NIM for NIM-loaded MCLN was 214%. MCLN exhibited negligible toxicity. The data reported herein suggest that the MCLN matrix is a promising carrier for controlling the drug release rate and improving the oral absorption of poorly water-soluble drugs.

Optimizing the balance between task automation and human manual control in simulated submarine track management.

PubMed

Chen, Stephanie I; Visser, Troy A W; Huf, Samuel; Loft, Shayne

2017-09-01

Automation can improve operator performance and reduce workload, but can also degrade operator situation awareness (SA) and the ability to regain manual control. In 3 experiments, we examined the extent to which automation could be designed to benefit performance while ensuring that individuals maintained SA and could regain manual control. Participants completed a simulated submarine track management task under varying task load. The automation was designed to facilitate information acquisition and analysis, but did not make task decisions. Relative to a condition with no automation, the continuous use of automation improved performance and reduced subjective workload, but degraded SA. Automation that was engaged and disengaged by participants as required (adaptable automation) moderately improved performance and reduced workload relative to no automation, but degraded SA. Automation engaged and disengaged based on task load (adaptive automation) provided no benefit to performance or workload, and degraded SA relative to no automation. Automation never led to significant return-to-manual deficits. However, all types of automation led to degraded performance on a nonautomated task that shared information processing requirements with automated tasks. Given these outcomes, further research is urgently required to establish how to design automation to maximize performance while keeping operators cognitively engaged. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Self-directed study using MP3 players to improve auscultation proficiency of physicians: a randomized, controlled trial.

PubMed

Donato, Anthony A; Kaliyadan, Antony G; Wasser, Thomas

2014-01-01

Studies of physicians at all levels of training demonstrate significant deficiencies in cardiac auscultation skills. The best instructional methods to augment these skills are not known. This study was a randomized, controlled trial of 83 noncardiologist volunteers exposed to a 12-week lower cognitive load self-study group using MP3 players containing heart sound audio files compared to a group receiving a 1-time 1-hour higher cognitive load multimedia lecture using the same audio files. The primary outcome measure was change in 15-question posttest score at 4 and 12 weeks as compared to pretest on recognition of identical audio files introduced during training. In the self-study group, the association of total exposure and deliberate practice effort (estimated by standard deviation of files played/mean) to improvement in test score was measured as a secondary end point. Self-study group participants improved as compared to pretest by 4.42 ± 3.41 answers correct at 12 weeks (5.09-9.51 correct, p < .001), while those exposed to the multimedia lecture improved by an average of 1.13 ± 3.2 answers correct (4.48-5.61 correct, p = .03). In the self-study arm, improvement in the posttest was positively associated with both total exposure (β = 0.55, p < .001) and deliberate practice score (β = 0.31, p = .02). A lower cognitive load self-study of audio files improved recognition of cardiac sounds, as compared to multimedia lecture, and deliberate practice strategies improved study efficiency. More investigation is needed to assess transfer of learning to a wider range of cardiac sounds in both simulated and clinical environments. © 2014 The Alliance for Continuing Education in the Health Professions, the Society for Academic Continuing Medical Education, and the Council on Continuing Medical Education, Association for Hospital Medical Education.

Designing, producing, and constructing fine-graded hot mix asphalt on Illinois roadways.

DOT National Transportation Integrated Search

2015-04-01

Fine-graded (F-G) asphalt concrete mixtures are composed of an aggregate structure in which the fine fraction controls the : load-carrying capacity of the mix. Other states have reported benefits in using F-G mixtures, including improved compaction, ...

Induction motor speed control using varied duty cycle terminal voltage via PI controller

NASA Astrophysics Data System (ADS)

Azwin, A.; Ahmed, S.

2018-03-01

This paper deals with the PI speed controller for the three-phase induction motor using PWM technique. The PWM generated signal is utilized for voltage source inverter with an optimal duty cycle on a simplified induction motor model. A control algorithm for generating PWM control signal is developed. Obtained results shows that the steady state error and overshoot of the developed system is in the limit under different speed and load condition. The robustness of the control performance would be potential for induction motor performance improvement.

Kaatsu training to enhance physical function of older adults with knee osteoarthritis: Design of a randomized controlled trial.

PubMed

Buford, Thomas W; Fillingim, Roger B; Manini, Todd M; Sibille, Kimberly T; Vincent, Kevin R; Wu, Samuel S

2015-07-01

As the U.S. population ages, efficacious interventions are needed to manage pain and maintain physical function among older adults with osteoarthritis (OA). Skeletal muscle weakness is a primary contributory factor to pain and functional decline among persons with OA, thus interventions are needed that improve muscle strength. High-load resistance exercise is the best-known method of improving muscle strength; however high-compressive loads commonly induce significant joint pain among persons with OA. Thus interventions with low-compressive loads are needed which improve muscle strength while limiting joint stress. This study is investigating the potential of an innovative training paradigm, known as Kaatsu, for this purpose. Kaatsu involves performing low-load exercise while externally-applied compression partially restricts blood flow to the active skeletal muscle. The objective of this randomized, single-masked pilot trial is to evaluate the efficacy and feasibility of chronic Kaatsu training for improving skeletal muscle strength and physical function among older adults. Participants aged ≥ 60 years with physical limitations and symptomatic knee OA will be randomly assigned to engage in a 3-month intervention of either (1) center-based, moderate-load resistance training, or (2) Kaatsu training matched for overall workload. Study dependent outcomes include the change in 1) knee extensor strength, 2) objective measures of physical function, and 3) subjective measures of physical function and pain. This study will provide novel information regarding the therapeutic potential of Kaatsu training while also informing about the long-term clinical viability of the paradigm by evaluating participant safety, discomfort, and willingness to continually engage in the intervention. Copyright © 2015 Elsevier Inc. All rights reserved.

Structural Dynamic Behavior of Wind Turbines

NASA Technical Reports Server (NTRS)

Thresher, Robert W.; Mirandy, Louis P.; Carne, Thomas G.; Lobitz, Donald W.; James, George H. III

2009-01-01

The structural dynamicist s areas of responsibility require interaction with most other members of the wind turbine project team. These responsibilities are to predict structural loads and deflections that will occur over the lifetime of the machine, ensure favorable dynamic responses through appropriate design and operational procedures, evaluate potential design improvements for their impact on dynamic loads and stability, and correlate load and control test data with design predictions. Load prediction has been a major concern in wind turbine designs to date, and it is perhaps the single most important task faced by the structural dynamics engineer. However, even if we were able to predict all loads perfectly, this in itself would not lead to an economic system. Reduction of dynamic loads, not merely a "design to loads" policy, is required to achieve a cost-effective design. The two processes of load prediction and structural design are highly interactive: loads and deflections must be known before designers and stress analysts can perform structural sizing, which in turn influences the loads through changes in stiffness and mass. Structural design identifies "hot spots" (local areas of high stress) that would benefit most from dynamic load alleviation. Convergence of this cycle leads to a turbine structure that is neither under-designed (which may result in structural failure), nor over-designed (which will lead to excessive weight and cost).

Volttron version 5.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

VOLTTRON is an agent execution platform providing services to its agents that allow them to easily communicate with physical devices and other resources. VOLTTRON delivers an innovative distributed control and sensing software platform that supports modern control strategies, including agent-based and transaction-based controls. It enables mobile and stationary software agents to perform information gathering, processing, and control actions. VOLTTRON can independently manage a wide range of applications, such as HVAC systems, electric vehicles, distributed energy or entire building loads, leading to improved operational efficiency.

V/STOL tilt rotor aircraft study. Volume 7: Tilt rotor flight control program feedback studies

NASA Technical Reports Server (NTRS)

Alexander, H. R.; Eason, W.; Gillmore, K.; Morris, J.; Spittle, R.

1973-01-01

An exploratory study has been made of the use of feedback control in tilt rotor aircraft. This has included the use of swashplate cyclic and collective controls and direct lift control. Various sensor and feedback systems are evaluated in relation to blade loads alleviation, improvement in flying qualities, and modal suppression. Recommendations are made regarding additional analytical and wind tunnel investigations and development of feedback systems in the full scale flight vehicle. Estimated costs and schedules are given.

Method of controlling switching of a multiphase inductor-converter bridge. [Patent application

DOEpatents

Kustom, R.L.; Fuja, R.E.

In an inductor-convertor circuit for transferring electrical energy between a storage coil and a load coil through a storage thyristor bridge, a load thyristor bridge, and a set of commutating capacitors, operation is improved by a method of changing the rate of delivery of energy in a given direction. The change in rate corresponds to a predetermined change in phase angle between the load bridge and the storage bridge, and comprises changing the phase of the bridge by two steps, each equal to half the predetermined change and occurring 180/sup 0/ apart. The method assures commutation and minimizes imbalances that lead otherwise to overvoltages. 11 figures.

A flight-test and simulation evaluation of the longitudinal final approach and landing performance of an automatic system for a light wing loading STOL aircraft equipped with wing spoilers

NASA Technical Reports Server (NTRS)

Brown, S. C.; Hardy, G. H.; Hindson, W. S.

1984-01-01

As part of a comprehensive flight-test investigation of short takeoff and landing (STOL) operating systems for the terminal systems for the terminal area, an automatic landing system has been developed and evaluated for a light wing-loading turboprop-powered aircraft. An advanced digital avionics system performed display, navigation, guidance, and control functions for the test aircraft. Control signals were generated in order to command powered actuators for all conventional controls and for a set of symmetrically driven wing spoilers. This report describes effects of the spoiler control on longitudinal autoland (automatic landing) performance. Flight-test results, with and without spoiler control, are presented and compared with available (basically, conventional takeoff and landing) performance criteria. These comparisons are augmented by results from a comprehensive simulation of the controlled aircraft that included representations of the microwave landing system navigation errors that were encountered in flight as well as expected variations in atmospheric turbulence and wind shear. Flight-test results show that the addition of spoiler control improves the touchdown performance of the automatic landing system. Spoilers improve longitudinal touchdown and landing pitch-attitude performance, particularly in tailwind conditions. Furthermore, simulation results indicate that performance would probably be satisfactory for a wider range of atmospheric disturbances than those encountered in flight. Flight results also indicate that the addition of spoiler control during the final approach does not result in any measurable change in glidepath track performance, and results in a very small deterioration in airspeed tracking. This difference contrasts with simulations results, which indicate some improvement in glidepath tracking and no appreciable change in airspeed tracking. The modeling problem in the simulation that contributed to this discrepancy with flight was not resolved.

Tendon neuroplastic training: changing the way we think about tendon rehabilitation: a narrative review

PubMed Central

Rio, Ebonie; Kidgell, Dawson; Moseley, G Lorimer; Docking, Sean; Purdam, Craig; Cook, Jill

2016-01-01

Tendinopathy can be resistant to treatment and often recurs, implying that current treatment approaches are suboptimal. Rehabilitation programmes that have been successful in terms of pain reduction and return to sport outcomes usually include strength training. Muscle activation can induce analgesia, improving self-efficacy associated with reducing one's own pain. Furthermore, strength training is beneficial for tendon matrix structure, muscle properties and limb biomechanics. However, current tendon rehabilitation may not adequately address the corticospinal control of the muscle, which may result in altered control of muscle recruitment and the consequent tendon load, and this may contribute to recalcitrance or symptom recurrence. Outcomes of interest include the effect of strength training on tendon pain, corticospinal excitability and short interval cortical inhibition. The aims of this concept paper are to: (1) review what is known about changes to the primary motor cortex and motor control in tendinopathy, (2) identify the parameters shown to induce neuroplasticity in strength training and (3) align these principles with tendon rehabilitation loading protocols to introduce a combination approach termed as tendon neuroplastic training. Strength training is a powerful modulator of the central nervous system. In particular, corticospinal inputs are essential for motor unit recruitment and activation; however, specific strength training parameters are important for neuroplasticity. Strength training that is externally paced and akin to a skilled movement task has been shown to not only reduce tendon pain, but modulate excitatory and inhibitory control of the muscle and therefore, potentially tendon load. An improved understanding of the methods that maximise the opportunity for neuroplasticity may be an important progression in how we prescribe exercise-based rehabilitation in tendinopathy for pain modulation and potentially restoration of the corticospinal control of the muscle-tendon complex. PMID:26407586

Model-based active control of a continuous structure subjected to moving loads

NASA Astrophysics Data System (ADS)

Stancioiu, D.; Ouyang, H.

2016-09-01

Modelling of a structure is an important preliminary step of structural control. The main objectives of the modelling, which are almost always antagonistic are accuracy and simplicity of the model. The first part of this study focuses on the experimental and theoretical modelling of a structure subjected to the action of one or two decelerating moving carriages modelled as masses. The aim of this part is to obtain a simple but accurate model which will include not only the structure-moving load interaction but also the actuators dynamics. A small scale rig is designed to represent a four-span continuous metallic bridge structure with miniature guiding rails. A series of tests are run subjecting the structure to the action of one or two minicarriages with different loads that were launched along the structure at different initial speeds. The second part is dedicated to model based control design where a feedback controller is designed and tested against the validated model. The study shows that a positive position feedback is able to improve system dynamics but also shows some of the limitations of state- space methods for this type of system.

Nanoethosomal formulation of gammaoryzanol for skin-aging protection and wrinkle improvement: a histopathological study.

PubMed

Heydari, Saman; Ghanbarzadeh, Saeed; Anoush, Behzad; Ranjkesh, Mohammadreza; Javadzadeh, Yousef; Kouhsoltani, Maryam; Hamishehkar, Hamed

2017-07-01

Free radical scavengers and antioxidants, with the main focus on enhanced targeting to the skin layers, can provide protection against skin ageing. The aim of the present study was to prepare nanoethosomal formulation of gammaoryzanol (GO), a water insoluble antioxidant, for its dermal delivery to prevent skin aging. Nanoethosomal formulation was prepared by a modified ethanol injection method and characterized by using laser light scattering, scanning electronic microscope (SEM) and X-ray diffraction (XRD) techniques. The effects of formulation parameters on nanoparticle size, encapsulation efficiency percent (EE%) and loading capacity percent (LC%) were investigated. Antioxidant activity of GO-loaded formulation was investigated in vitro using normal African green monkey kidney fibroblast cells (Vero). The effect of control and GO-loaded nanoethosomal formulation on superoxide dismutase (SOD) and malondialdehyde (MDA) content of rat skin was also probed. Furthermore, the effect of GO-loaded nanoethosomes on skin wrinkle improvement was studied by dermoscopic and histological examination on healthy humans and UV-irradiated rats, respectively. The optimized nanoethosomal formulation showed promising characteristics including narrow size distribution 0.17 ± 0.02, mean diameter of 98.9 ± 0.05 nm, EE% of 97.12 ± 3.62%, LC% of 13.87 ± 1.36% and zeta potential value of -15.1 ± 0.9 mV. The XRD results confirmed uniform drug dispersion in the nanoethosomes structure. In vitro and in vivo antioxidant studies confirmed the superior antioxidant effect of GO-loaded nanoethosomal formulation compared with control groups (blank nanoethosomes and GO suspension). Nanoethosomes was a promising carrier for dermal delivery of GO and consequently had superior anti-aging effect.

Sleeve Gastrectomy in Morbidly Obese HIV Patients: Focus on Anti-retroviral Treatment Absorption After Surgery.

PubMed

Amouyal, Chloé; Buyse, Marion; Lucas-Martini, Lea; Hirt, Déborah; Genser, Laurent; Torcivia, Adriana; Bouillot, Jean-Luc; Oppert, Jean-Michel; Aron-Wisnewsky, Judith

2018-05-20

Anti-retroviral therapy (ART) dramatically reduced AIDS development, thus enabling patients to live as long as the general population. New challenges have emerged particularly cardiometabolic diseases and weight gain, with some HIV patients seeking bariatric surgery (BS). However, BS outcomes during HIV remain poorly described, with scarce data on ART pharmacokinetic post-BS. Describing sleeve gastrectomy (SG) results in HIV patients in terms of ART pharmacokinetic, HIV control, weight loss, and metabolic outcomes. Prospective study of HIV patients undergoing SG in a referral academic center, with at least 6 months follow-up. Clinical and biological parameters, HIV medical history, and ART pharmacokinetics were gathered before and post-SG. Seventeen patients (mean BMI = 44.2 ± 5.7 kg m -2 ) and major obesity-related diseases (47% type-2 diabetes, 64% obstructive sleep apnea, 70% hypertension) underwent SG during a mean 2 years of follow-up. They displayed an average of 20% reduction of initial BMI and improved body composition, similarly to obese non-HIV patients. SG improved metabolic status. All patients had undetectable viral load before BS. Upon HIV follow-up, 12 patients had undetectable viral load with correct ART kinetic parameters (3 and 6 months); 4 displayed detectable viral load along with significant decrease in raltegravir and atazanavir treatment exposure, leading to ART change with subsequent undetectable viral load; and 1 had persistent detectable viral load despite ART change. SG seems effective and safe in obese HIV patients. However, ART treatment should be monitored post-SG to control HIV infection. We suggest that some ART should be adapted before SG conjoints with infectious disease specialists.

Effects of melamine formaldehyde resin and CaCO3 diffuser-loaded encapsulation on correlated color temperature uniformity of phosphor-converted LEDs.

PubMed

Yang, Liang; Lv, Zhicheng; Jiaojiao, Yuan; Liu, Sheng

2013-08-01

Phosphor-free dispensing is the most widely used LED packaging method, but this method results in poor quality in angular CCT uniformity. This study proposes a diffuser-loaded encapsulation to solve the problem; the effects of melamine formaldehyde (MF) resin and CaCO3 loaded encapsulation on correlated color temperature (CCT) uniformity and luminous efficiency reduction of the phosphor-converted LEDs are investigated. Results reveal that MF resin loaded encapsulation has better light diffusion performance compared to MF resin loaded encapsulation at the same diffuser concentration, but CaCO3 loaded encapsulation has better luminous efficiency maintenance. The improvements in angular color uniformity for the LEDs emitting with MF resin and CaCO3 loaded encapsulation can be explained by the increase in photon scattering. The utility of this low cost and controllable mineral diffuser packaging method provides a practical approach for enhancing the angular color uniformity of LEDs. The diffuser mass ratio of 1% MF resin or 10% CaCO3 is the optimum condition to obtain low angular CCT variance and high luminous efficiency.

A Closed-Loop Optimal Neural-Network Controller to Optimize Rotorcraft Aeromechanical Behaviour. Volume 1; Theory and Methodology

NASA Technical Reports Server (NTRS)

Leyland, Jane Anne

2001-01-01

Given the predicted growth in air transportation, the potential exists for significant market niches for rotary wing subsonic vehicles. Technological advances which optimise rotorcraft aeromechanical behaviour can contribute significantly to both their commercial and military development, acceptance, and sales. Examples of the optimisation of rotorcraft aeromechanical behaviour which are of interest include the minimisation of vibration and/or loads. The reduction of rotorcraft vibration and loads is an important means to extend the useful life of the vehicle and to improve its ride quality. Although vibration reduction can be accomplished by using passive dampers and/or tuned masses, active closed-loop control has the potential to reduce vibration and loads throughout a.wider flight regime whilst requiring less additional weight to the aircraft man that obtained by using passive methads. It is ernphasised that the analysis described herein is applicable to all those rotorcraft aeromechanical behaviour optimisation problems for which the relationship between the harmonic control vector and the measurement vector can be adequately described by a neural-network model.

Potentials of real time control, stormwater infiltration and urine separation to minimize river impacts: dynamic long term simulation of sewer network, pumping stations, pressure pipes and waste water treatment plant.

PubMed

Peters, C; Keller, S; Sieker, H; Jekel, M

2007-01-01

River Panke (Berlin, Germany) suffers from hydraulic peak loads and pollutant loads from separate sewers and combined sewer overflows (CSOs). Pumping the wastewater through long pressure pipes causes extreme peak loads to the wastewater treatment plant (WWTP) during stormwater events. In order to find a good solution, it is essential not to decide on one approach at the beginning, but to evaluate a number of different approaches. For this reason, an integrated simulation study is carried out, assessing the potentials of real time control (RTC), stormwater infiltration, storage and urine separation. Criteria for the assessment are derived and multi-criteria analysis is applied. Despite spatial limitations, infiltration has the highest potential and is very effective with respect to both overflows and the WWTP. Due to a high percentage of separate systems, urine separation has a similar potential and causes the strongest benefits at the WWTP. Unconventional control strategies can lead to significant improvement (comparable to infiltrating the water from approximately 10% of the sealed area).

Targeted Doxorubicin-Loaded Bacterially Derived Nano-Cells for the Treatment of Neuroblastoma.

PubMed

Sagnella, Sharon M; Trieu, Jennifer; Brahmbhatt, Himanshu; MacDiarmid, Jennifer A; MacMillan, Alex; Whan, Renee M; Fife, Christopher M; McCarroll, Joshua A; Gifford, Andrew J; Ziegler, David S; Kavallaris, Maria

2018-05-01

Advanced stage neuroblastoma is an aggressive disease with limited treatment options for patients with drug-resistant tumors. Targeted delivery of chemotherapy for pediatric cancers offers promise to improve treatment efficacy and reduce toxicity associated with systemic chemotherapy. The EnGeneIC Dream Vector (EDV TM ) is a nanocell, which can package chemotherapeutic drugs and target tumors via attachment of bispecific proteins to the surface of the nanocell. Phase I trials in adults with refractory tumors have shown an acceptable safety profile. Herein we investigated the activity of EGFR-targeted and doxorubicin-loaded EDV TM ( EGFR EDV TM Dox ) for the treatment of neuroblastoma. Two independent neuroblastoma cell lines with variable expression of EGFR protein [SK-N-BE(2), high; SH-SY-5Y, low] were used. EGFR EDV TM Dox induced apoptosis in these cells compared to control, doxorubicin, or non-doxorubicin loaded EGFR EDV TM In three-dimensional tumor spheroids, imaging and fluorescence life-time microscopy revealed that EGFR EDV TM Dox had a marked enhancement of doxorubicin penetration compared to doxorubicin alone, and improved penetration compared to non-EGFR-targeted EDV TM Dox , with enhanced spheroid penetration leading to increased apoptosis. In two independent orthotopic human neuroblastoma xenograft models, short-term studies (28 days) of tumor-bearing mice led to a significant decrease in tumor size in EGFR EDV TM Dox -treated animals compared to control, doxorubicin, or non-EGFR EDV TM Dox There was increased TUNEL staining of tumors at day 28 compared to control, doxorubicin, or non-EGFR EDV TM Dox Moreover, overall survival was increased in neuroblastoma mice treated with EGFR EDV TM Dox ( P < 0007) compared to control. Drug-loaded bispecific-antibody targeted EDVs TM offer a highly promising approach for the treatment of aggressive pediatric malignancies such as neuroblastoma. Mol Cancer Ther; 17(5); 1012-23. ©2018 AACR . ©2018 American Association for Cancer Research.

Slow loaded breathing training improves blood pressure, lung capacity and arm exercise endurance for older people with treated and stable isolated systolic hypertension.

PubMed

Ublosakka-Jones, Chulee; Tongdee, Phailin; Pachirat, Orathai; Jones, David A

2018-03-28

Hypertension and reduced lung function are important features of aging. Slow loaded breathing training reduces resting blood pressure and the question is whether this can also improve lung function. Thirty-two people (67 ± 5 years, 16 male) with controlled isolated systolic hypertension undertook an eight weeks randomised controlled training trial with an inspiratory load of 25% maximum inspiratory pressure (MIP) at 6 breaths per minute (slow loaded breathing; SLB) or deep breathing control (CON). Outcome measures were resting blood pressure (BP) and heart rate; MIP; lung capacity; chest and abdominal expansion; arm cranking exercise endurance at 50% heart rate reserve. Home based measurement of resting systolic BP decreased by 20 mm Hg (15 to 25) (Mean and 95%CI) for SLB and by 5 mm Hg (1 to 7) for CON. Heart rate and diastolic BP also decreased significantly for SLB but not CON. MIP increased by 15.8 cm H 2 O (11.8 to 19.8) and slow vital capacity by 0.21 L (0.15 to 0.27) for SLB but not for CON. Chest and abdominal expansion increased by 2.3 cm (2.05 to 2.55) and 2.5 cm (2.15 to 2.85), respectively for SLB and by 0.5 cm (0.26 to 0.74) and 1.7 cm (1.32 to 2.08) for CON. Arm exercise time increased by 4.9 min (3.65 to 5.15) for SLB with no significant change for CON. Slow inspiratory muscle training is not only effective in reducing resting BP, even in older people with well controlled isolated systolic hypertension but also increases inspiratory muscle strength, lung capacity and arm exercise duration. Copyright © 2018. Published by Elsevier Inc.

Development and evaluation of automatic landing control laws for light wing loading STOL aircraft

NASA Technical Reports Server (NTRS)

Feinreich, B.; Degani, O.; Gevaert, G.

1981-01-01

Automatic flare and decrab control laws were developed for NASA's experimental Twin Otter. This light wing loading STOL aircraft was equipped with direct lift control (DLC) wing spoilers to enhance flight path control. Automatic landing control laws that made use of the spoilers were developed, evaluated in a simulation and the results compared with these obtained for configurations that did not use DLC. The spoilers produced a significant improvement in performance. A simulation that could be operated faster than real time in order to provide statistical landing data for a large number of landings over a wide spectrum of disturbances in a short time was constructed and used in the evaluation and refinement of control law configurations. A longitudinal control law that had been previously developed and evaluated in flight was also simulated and its performance compared with that of the control laws developed. Runway alignment control laws were also defined, evaluated, and refined to result in a final recommended configuration. Good landing performance, compatible with Category 3 operation into STOL runways, was obtained.

Safety halls--an evaluation.

PubMed

Nyberg, Anders; Gregersen, Nils Petter; Nolén, Sixten; Engström, Inger

2005-01-01

In most countries, drivers licensing systems usually include teaching some aspects of using safety equipment (e.g., airbags and seat belts). However, there is now evidence worldwide that such education is inadequate, as indicated by, for example, the overrepresentation of young drivers who do not use seat belts. A randomized controlled study was conducted in Sweden to evaluate the effects of visiting a facility known as a "safety hall" in combination with the mandatory skid training. The results were assessed to determine the effects of the knowledge and attitudes of learner drivers in the following subjects: airbags, securing loads, seat belts, sitting posture, speed, and tires. An experimental group and a control group comprising 658 and 668 learners, respectively, answered identical questionnaires on three different occasions (pretest, posttest 1, and posttest 2). The results show that, for most of the topics considered, knowledge and attitudes in both groups were better at posttest 2 than at the pretest, and in general, the best knowledge and attitudes were found in the experimental group. The combined safety/skid training seems to have had the greatest effect on seat belts and loads. The findings also indicate that the safety halls can be further improved to achieve an even better effect. The use of safety halls has improved the knowledge and attitudes of learner drivers concerning several important areas related to traffic safety. Since knowledge and attitudes are important predictors of behavior, implementing safety halls can be expected to lead to improvements, especially regarding the use of safety belts and securing loads.

Virtual Reality Training with Cognitive Load Improves Walking Function in Chronic Stroke Patients.

PubMed

Cho, Ki Hun; Kim, Min Kyu; Lee, Hwang-Jae; Lee, Wan Hee

2015-08-01

Virtual reality training is considered as an effective intervention method of stroke patients, and the virtual reality system for therapeutic rehabilitation has emphasized the cognitive factors to improve walking function. The purpose of current study was to investigate the effect of virtual reality training with cognitive load (VRTCL) on walking function of chronic stroke. Chronic stroke patients were randomly assigned to the VRTCL group (11 patients, including 5 men; mean age, 60.0 years; post-stroke duration, 273.9 days) or control group (11 patients, including 2 men; mean age, 58.6 years; post-stroke duration, 263.9 days). All subjects participated in the standard rehabilitation program that consisted of physical and occupational therapies. In addition, VRTCL group participated in the VRTCL for 4 weeks (30 min per day and five times a week), while those in the control group participated in virtual reality treadmill training. Walking function under single (walking alone) and dual task (walking with cognitive tasks) conditions was assessed using an electrical walkway system. After the 4-week intervention, under both single and dual task conditions, significant improvement on walking function was observed in VRTCL and control groups (P < 0.05). In addition, in the dual task condition, greater improvement on walking function was observed in the VRTCL group, compared with the control group (P < 0.05). These findings demonstrated the efficacy of VRTCL on the walking function under the dual task condition. Therefore, we suggest that VRTCL may be an effective method for the achievement of independent walking in chronic stroke patients.

Simulation and evaluation of pollution load reduction scenarios for water environmental management: a case study of inflow river of Taihu Lake, China.

PubMed

Zhang, Ruibin; Qian, Xin; Zhu, Wenting; Gao, Hailong; Hu, Wei; Wang, Jinhua

2014-09-09

In the beginning of the 21st century, the deterioration of water quality in Taihu Lake, China, has caused widespread concern. The primary source of pollution in Taihu Lake is river inflows. Effective pollution load reduction scenarios need to be implemented in these rivers in order to improve the water quality of Taihu Lake. It is important to select appropriate pollution load reduction scenarios for achieving particular goals. The aim of this study was to facilitate the selection of appropriate scenarios. The QUAL2K model for river water quality was used to simulate the effects of a range of pollution load reduction scenarios in the Wujin River, which is one of the major inflow rivers of Taihu Lake. The model was calibrated for the year 2010 and validated for the year 2011. Various pollution load reduction scenarios were assessed using an analytic hierarchy process, and increasing rates of evaluation indicators were predicted using the Delphi method. The results showed that control of pollution from the source is the optimal method for pollution prevention and control, and the method of "Treatment after Pollution" has bad environmental, social and ecological effects. The method applied in this study can assist for environmental managers to select suitable pollution load reduction scenarios for achieving various objectives.

Simulation and Evaluation of Pollution Load Reduction Scenarios for Water Environmental Management: A Case Study of Inflow River of Taihu Lake, China

PubMed Central

Zhang, Ruibin; Qian, Xin; Zhu, Wenting; Gao, Hailong; Hu, Wei; Wang, Jinhua

2014-01-01

In the beginning of the 21st century, the deterioration of water quality in Taihu Lake, China, has caused widespread concern. The primary source of pollution in Taihu Lake is river inflows. Effective pollution load reduction scenarios need to be implemented in these rivers in order to improve the water quality of Taihu Lake. It is important to select appropriate pollution load reduction scenarios for achieving particular goals. The aim of this study was to facilitate the selection of appropriate scenarios. The QUAL2K model for river water quality was used to simulate the effects of a range of pollution load reduction scenarios in the Wujin River, which is one of the major inflow rivers of Taihu Lake. The model was calibrated for the year 2010 and validated for the year 2011. Various pollution load reduction scenarios were assessed using an analytic hierarchy process, and increasing rates of evaluation indicators were predicted using the Delphi method. The results showed that control of pollution from the source is the optimal method for pollution prevention and control, and the method of “Treatment after Pollution” has bad environmental, social and ecological effects. The method applied in this study can assist for environmental managers to select suitable pollution load reduction scenarios for achieving various objectives. PMID:25207492

Travel better, travel longer : a pocket guide to improve traffic control and mobility for our older population

DOT National Transportation Integrated Search

1995-02-01

Pavement related effects of changes in truck size and weight regulations include the following: (1) Increased traffic loadings require thicker pavements which, in turn, increase the construction cost of pavements. (2) For existing pavements, increase...

Stabilizing ultrasmall Au clusters for enhanced photoredox catalysis.

PubMed

Weng, Bo; Lu, Kang-Qiang; Tang, Zichao; Chen, Hao Ming; Xu, Yi-Jun

2018-04-18

Recently, loading ligand-protected gold (Au) clusters as visible light photosensitizers onto various supports for photoredox catalysis has attracted considerable attention. However, the efficient control of long-term photostability of Au clusters on the metal-support interface remains challenging. Herein, we report a simple and efficient method for enhancing the photostability of glutathione-protected Au clusters (Au GSH clusters) loaded on the surface of SiO 2 sphere by utilizing multifunctional branched poly-ethylenimine (BPEI) as a surface charge modifying, reducing and stabilizing agent. The sequential coating of thickness controlled TiO 2 shells can further significantly improve the photocatalytic efficiency, while such structurally designed core-shell SiO 2 -Au GSH clusters-BPEI@TiO 2 composites maintain high photostability during longtime light illumination conditions. This joint strategy via interfacial modification and composition engineering provides a facile guideline for stabilizing ultrasmall Au clusters and rational design of Au clusters-based composites with improved activity toward targeting applications in photoredox catalysis.

Space Shuttle development update

NASA Technical Reports Server (NTRS)

Brand, V.

1984-01-01

The development efforts, since the STS-4 flight, in the Space Shuttle (SS) program are presented. The SS improvements introduced in the last two years include lower-weight loads, communication through the Tracking and Data Relay Satellite, expanded extravehicular activity capability, a maneuvering backpack and the manipulator foot restraint, the improvements in thermal projection system, the 'optional terminal area management targeting' guidance software, a rendezvous system with radar and star tracker sensors, and improved on-orbit living conditions. The flight demonstrations include advanced launch techniques (e.g., night launch and direct insertion to orbit); the on-orbit demonstrations; and added entry and launching capabilities. The entry aerodynamic analysis and entry flight control fine tuning are described. Reusability, improved ascent performance, intact abort and landing flexibility, rollout control, and 'smart speedbrakes' are among the many improvements planned for the future.

ASDTIC: A feedback control innovation

NASA Technical Reports Server (NTRS)

Lalli, V. R.; Schoenfeld, A. D.

1972-01-01

The ASDTIC (Analog Signal to Discrete Time Interval Converter) control subsystem provides precise output control of high performance aerospace power supplies. The key to ASDTIC operation is that it stably controls output by sensing output energy change as well as output magnitude. The ASDTIC control subsystem and control module were developed to improve power supply performance during static and dynamic input voltage and output load variations, to reduce output voltage or current regulation due to component variations or aging, to maintain a stable feedback control with variations in the loop gain or loop time constants, and to standardize the feedback control subsystem for power conditioning equipment.

ASDTIC - A feedback control innovation.

NASA Technical Reports Server (NTRS)

Lalli, V. R.; Schoenfeld, A. D.

1972-01-01

The ASDTIC (analog signal to discrete time interval converter) control subsystem provides precise output control of high performance aerospace power supplies. The key to ASDTIC operation is that it stably controls output by sensing output energy change as well as output magnitude. The ASDTIC control subsystem and control module were developed to improve power supply performance during static and dynamic input voltage and output load variations, to reduce output voltage or current regulation due to component variations or aging, to maintain a stable feedback control with variations in the loop gain or loop time constants, and to standardize the feedback control subsystem for power conditioning equipment.

Comparison of the stability of various internal fixators used in the treatment of osteochondritis dissecans--a mechanical model.

PubMed

Morelli, Moreno; Poitras, Philippe; Grimes, Valentine; Backman, David; Dervin, Geoffrey

2007-04-01

The purpose of this study was to determine what characteristics of fixation devices used in the treatment of osteochondritis dissecans (OCD) contribute to improved stability to resist shear loading. An OCD model was designed using rigid polyurethane foam. Each specimen consisted of two components, an osteochondral fragment and a corresponding defect. A total of 40 specimens were prepared and assigned to one of four groups: control (no extrinsic stabilizer); two 2-mm-diameter Kirschner wires (K-wires), 40 mm in length; one threaded washer and a 28-mm screw; and one threaded washer and a 38 mm screw. Each specimen was mounted onto an Iosipescu shear test fixture and subjected to shear loads at a pseudo-static displacement rate of 0.075 mm/s. All groups demonstrated some stability; controls were significantly less stable than all other groups. The group with the threaded washer and 38-mm screw demonstrated the greatest stability (p < 0.001), and no difference was noted between the K-wire and 28-mm screw groups. These results suggest that, in this OCD model, friction conferred some intrinsic stability to resist loads in shear. However, stability was improved with the use of long implants that compressed the fragments together.

On-line IR analyzer system to monitor cephamycin C loading on ion-exchange resin

NASA Astrophysics Data System (ADS)

Shank, Sheldon; Russ, Warren; Gravatt, Douglas; Lee, Wesley; Donahue, Steven M.

1992-08-01

An on-line infrared analyzer is being developed for monitoring cephamycin C loading on ion exchange resin. Accurate measurement of product loading offers productivity improvements with direct savings from product loss avoidance, minimized raw material cost, and reduced off-line laboratory testing. Ultrafiltered fermentation broth is fed onto ion exchange columns under conditions which adsorb the product, cephamycin C, to the resin while allowing impurities to pass unretained. Product loading is stopped when the on-line analyzer determines that resin capacity for adsorbing product is nearly exhausted. Infrared spectroscopy has been shown capable of quantifying cephamycin C in the process matrix at concentrations that support process control decisions. Process-to-analyzer interface challenges have been resolved, including sample conditioning requirements. Analyzer requirements have been defined. The sample conditioning station is under design.

Opportunities for Energy Efficiency and Open Automated Demand Response in Wastewater Treatment Facilities in California -- Phase I Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lekov, Alex; Thompson, Lisa; McKane, Aimee

This report summarizes the Lawrence Berkeley National Laboratory?s research to date in characterizing energy efficiency and automated demand response opportunities for wastewater treatment facilities in California. The report describes the characteristics of wastewater treatment facilities, the nature of the wastewater stream, energy use and demand, as well as details of the wastewater treatment process. It also discusses control systems and energy efficiency and automated demand response opportunities. In addition, several energy efficiency and load management case studies are provided for wastewater treatment facilities.This study shows that wastewater treatment facilities can be excellent candidates for open automated demand response and thatmore » facilities which have implemented energy efficiency measures and have centralized control systems are well-suited to shift or shed electrical loads in response to financial incentives, utility bill savings, and/or opportunities to enhance reliability of service. Control technologies installed for energy efficiency and load management purposes can often be adapted for automated demand response at little additional cost. These improved controls may prepare facilities to be more receptive to open automated demand response due to both increased confidence in the opportunities for controlling energy cost/use and access to the real-time data.« less

An Improved Distributed Secondary Control Method for DC Microgrids With Enhanced Dynamic Current Sharing Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Panbao; Lu, Xiaonan; Yang, Xu

This paper proposes an improved distributed secondary control scheme for dc microgrids (MGs), aiming at overcoming the drawbacks of conventional droop control method. The proposed secondary control scheme can remove the dc voltage deviation and improve the current sharing accuracy by using voltage-shifting and slope-adjusting approaches simultaneously. Meanwhile, the average value of droop coefficients is calculated, and then it is controlled by an additional controller included in the distributed secondary control layer to ensure that each droop coefficient converges at a reasonable value. Hence, by adjusting the droop coefficient, each participating converter has equal output impedance, and the accurate proportionalmore » load current sharing can be achieved with different line resistances. Furthermore, the current sharing performance in steady and transient states can be enhanced by using the proposed method. The effectiveness of the proposed method is verified by detailed experimental tests based on a 3 × 1 kW prototype with three interface converters.« less

Fabrication of a Soybean Bowman-Birk Inhibitor (BBI) Nanodelivery Carrier To Improve Bioavailability of Curcumin.

PubMed

Liu, Chun; Cheng, Fenfen; Yang, Xiaoquan

2017-03-22

Curcumin is a poorly water-soluble drug, and its oral bioavailability is very low. Here, a novel self-assembly nanoparticle delivery carrier has been successfully developed by using soybean Bowman-Birk inhibitor (BBI) to improve the solubility, bioaccessibility, and oral absorption of curcumin. BBI is a unique protein, which can be resistant to the pH range and proteolytic enzymes in the gastrointestinal tract (GIT), bioavailable, and not allergenic. The encapsulation efficiencies (EE) and the loading capacities (LC) of curcumin in the curcumin-loaded BBI nanoparticles (Cur-BBI-NPs, size = 90.09 nm, PDI = 0.103) were 86.17 and 10.31%, respectively. The in vitro bioaccessibility of Cur-BBI-NPs was superior to that of curcumin-loaded sodium caseinate (SC) nanoparticles (Cur-SC-NPs) (as control). Moreover, Cur-BBI-NPs significantly enhanced the bioavailability of curcumin in rats compared with Cur-SC-NPs, and the clathrin-mediated endocytosis pathway probably contributed to the favorable bioavailability of Cur-BBI-NPs, as revealed by the cellular uptake inhibition study.

Preparation, characterization and stability of curcumin-loaded zein-shellac composite colloidal particles.

PubMed

Sun, Cuixia; Xu, Chenqi; Mao, Like; Wang, Di; Yang, Jie; Gao, Yanxiang

2017-08-01

Curcumin-loaded zein-shellac composite particles were prepared by the antisolvent co-precipitation method. The encapsulation efficiency of curcumin was significantly improved from 82.7% in zein particles to 93.2% in zein-shellac complex particles. The result of differential scanning calorimetry suggested that curcumin in the polymeric matrix was in an amorphous state. Fourier transform infrared spectroscopy analysis revealed that curcumin had non-covalently interacted with zein and shellac, mainly through hydrogen bonding and hydrophobic interaction. Aggregates in irregular shapes, with large sizes, were found by atomic force microscopy, and conglutination, integration or fusion of different entities into network structures occurred at a high level of shellac. At the mass ratio of zein to shellac of 1:1, curcumin in the complex particles exhibited improved photochemical and thermal stability. Curcumin-loaded zein-shellac complex particles allowed the controlled release of curcumin in both PBS medium and simulated gastrointestinal fluids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Single dental implant retained mandibular complete dentures – influence of the loading protocol: study protocol for a randomized controlled trial

PubMed Central

2014-01-01

Background Over the years, there has been a strong consensus in dentistry that at least two implants are required to retain a complete mandibular denture. It has been shown in several clinical trials that one single median implant can retain a mandibular overdenture sufficiently well for up to 5 years without implant failures, when delayed loading was used. However, other trials have reported conflicting results with in part considerable failure rates when immediate loading was applied. Therefore it is the purpose of the current randomized clinical trial to test the hypothesis that immediate loading of a single mandibular midline implant with an overdenture will result in a comparable clinical outcome as using the standard protocol of delayed loading. Methods/design This prospective nine-center randomized controlled clinical trial is still ongoing. The final patient will complete the trial in 2016. In total, 180 edentulous patients between 60 and 89 years with sufficient complete dentures will receive one median implant in the edentulous mandible, which will retain the existing complete denture using a ball attachment. Loading of the median implant is either immediately after implant placement (experimental group) or delayed by 3 months of submerged healing at second-stage surgery (control group). Follow-up of patients will be performed for 24 months after implant loading. The primary outcome measure is non-inferiority of implant success rate of the experimental group compared to the control group. The secondary outcome measures encompass clinical, technical and subjective variables. The study was funded by the Deutsche Forschungsgemeinschaft (German research foundation, KE 477/8-1). Discussion This multi-center clinical trial will give information on the ability of a single median implant to retain a complete mandibular denture when immediately loaded. If viable, this treatment option will strongly improve everyday dental practice. Trial registration The trial has been registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00003730 since 23 August 2012. (http://www.germanctr.de). PMID:24884848

Load control system. [for space shuttle external tank ground tests

NASA Technical Reports Server (NTRS)

Grosse, J. C.

1977-01-01

The load control system developed for the shuttle external structural tests is described. The system consists of a load programming/display module, and a load control module along with the following hydraulic system components: servo valves, dump valves, hydraulic system components, and servo valve manifold blocks. One load programming/display subsystem can support multiple load control subsystem modules.

Solid polymer electrolyte (SPE) fuel cell technology program, phase 2/2A. [testing and evaluations

NASA Technical Reports Server (NTRS)

1976-01-01

Test evaluations were performed on a fabricated single solid polymer electrolyte cell unit. The cell operated at increased current density and at higher performance levels. This improved performance was obtained through a combination of increased temperature, increased reactant pressures, improved activation techniques and improved thermal control over the baseline cell configuration. The cell demonstrated a higher acid content membrane which resulted in increased performance. Reduced catalyst loading and low cost membrane development showed encouraging results.

[Effect of antecedent dry weather period on urban storm runoff pollution load].

PubMed

Li, Li-qing; Yin, Cheng-qing; Kong, Ling-li; He, Qing-ci

2007-10-01

Twelve storm events were surveyed at Shilipu catchment in Wuhan City through three-year monitoring regime. The flow discharges, total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) in runoff were measured to study the mechanism of urban stormwater runoff pollution. The relationship between the event pollution load and the antecedent dry weather period was identified to discuss the influence of the urban surface sanitation management, operation of sewer pipe maintenance and rainfall characteristics on the urban stormwater runoff pollution. It was found that the antecedent dry weather period and runoff amount were the important determining factors in the generation of urban stormwater runoff pollution. The event pollution load was positively correlated to the antecedent dry weather period between two rainfall events (R2 = 0.95, p < 0.01). It was the most important hydrological factor influencing the events pollution loads. The best regression equation to estimate pollution load for storm events was developed based on the antecedent dry weather period and runoff depth. Source control including improving urban street sweeping activities and operation of sewer pipe maintenance should be made to reduce the amount of available pollutant over the dry days. It is important alternative to control urban stormwater runoff pollution for Hanyang District.

An enhanced SOCP-based method for feeder load balancing using the multi-terminal soft open point in active distribution networks

DOE PAGES

Ji, Haoran; Wang, Chengshan; Li, Peng; ...

2017-09-20

The integration of distributed generators (DGs) exacerbates the feeder power flow fluctuation and load unbalanced condition in active distribution networks (ADNs). The unbalanced feeder load causes inefficient use of network assets and network congestion during system operation. The flexible interconnection based on the multi-terminal soft open point (SOP) significantly benefits the operation of ADNs. The multi-terminal SOP, which is a controllable power electronic device installed to replace the normally open point, provides accurate active and reactive power flow control to enable the flexible connection of feeders. An enhanced SOCP-based method for feeder load balancing using the multi-terminal SOP is proposedmore » in this paper. Furthermore, by regulating the operation of the multi-terminal SOP, the proposed method can mitigate the unbalanced condition of feeder load and simultaneously reduce the power losses of ADNs. Then, the original non-convex model is converted into a second-order cone programming (SOCP) model using convex relaxation. In order to tighten the SOCP relaxation and improve the computation efficiency, an enhanced SOCP-based approach is developed to solve the proposed model. Finally, case studies are performed on the modified IEEE 33-node system to verify the effectiveness and efficiency of the proposed method.« less

Effect of occupant behavior and air-conditioner controls on humidity in typical and high-efficiency homes

DOE PAGES

Winkler, Jon; Munk, Jeffrey; Woods, Jason

2018-04-01

Increasing insulation levels and improved windows are reducing sensible cooling loads in high-efficiency homes. This trend raises concerns that the resulting shift in the balance of sensible and latent cooling loads may result in higher indoor humidity, occupant discomfort, and stunted adoption of high-efficiency homes. This study utilizes established moisture-buffering and air-conditioner latent degradation models in conjunction with an approach to stochastically model internal gains. Building loads and indoor humidity levels are compared for simulations of typical new construction homes and high-efficiency homes in 10 US cities. The sensitivity of indoor humidity to changes in cooling set point, air-conditioner capacity,more » and blower control parameters are evaluated. The results show that high-efficiency homes in humid climates have cooling loads with a higher fraction of latent loads than the typical new construction home, resulting in higher indoor humidity. Reducing the cooling set point is the easiest method to reduce indoor humidity, but it is not energy efficient, and overcooling may lead to occupant discomfort. Eliminating the blower operation at the end of cooling cycles and reducing the cooling airflow rate also reduce indoor humidity and with a smaller impact on energy use and comfort.« less

Effect of occupant behavior and air-conditioner controls on humidity in typical and high-efficiency homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winkler, Jon; Munk, Jeffrey; Woods, Jason

Increasing insulation levels and improved windows are reducing sensible cooling loads in high-efficiency homes. This trend raises concerns that the resulting shift in the balance of sensible and latent cooling loads may result in higher indoor humidity, occupant discomfort, and stunted adoption of high-efficiency homes. This study utilizes established moisture-buffering and air-conditioner latent degradation models in conjunction with an approach to stochastically model internal gains. Building loads and indoor humidity levels are compared for simulations of typical new construction homes and high-efficiency homes in 10 US cities. The sensitivity of indoor humidity to changes in cooling set point, air-conditioner capacity,more » and blower control parameters are evaluated. The results show that high-efficiency homes in humid climates have cooling loads with a higher fraction of latent loads than the typical new construction home, resulting in higher indoor humidity. Reducing the cooling set point is the easiest method to reduce indoor humidity, but it is not energy efficient, and overcooling may lead to occupant discomfort. Eliminating the blower operation at the end of cooling cycles and reducing the cooling airflow rate also reduce indoor humidity and with a smaller impact on energy use and comfort.« less

An enhanced SOCP-based method for feeder load balancing using the multi-terminal soft open point in active distribution networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ji, Haoran; Wang, Chengshan; Li, Peng

The integration of distributed generators (DGs) exacerbates the feeder power flow fluctuation and load unbalanced condition in active distribution networks (ADNs). The unbalanced feeder load causes inefficient use of network assets and network congestion during system operation. The flexible interconnection based on the multi-terminal soft open point (SOP) significantly benefits the operation of ADNs. The multi-terminal SOP, which is a controllable power electronic device installed to replace the normally open point, provides accurate active and reactive power flow control to enable the flexible connection of feeders. An enhanced SOCP-based method for feeder load balancing using the multi-terminal SOP is proposedmore » in this paper. Furthermore, by regulating the operation of the multi-terminal SOP, the proposed method can mitigate the unbalanced condition of feeder load and simultaneously reduce the power losses of ADNs. Then, the original non-convex model is converted into a second-order cone programming (SOCP) model using convex relaxation. In order to tighten the SOCP relaxation and improve the computation efficiency, an enhanced SOCP-based approach is developed to solve the proposed model. Finally, case studies are performed on the modified IEEE 33-node system to verify the effectiveness and efficiency of the proposed method.« less

Improving sustained drug delivery from ophthalmic lens materials through the control of temperature and time of loading.

PubMed

Topete, Ana; Oliveira, Andreia S; Fernandes, A; Nunes, T G; Serro, A P; Saramago, B

2018-05-30

Although the possibility of using drug-loaded ophthalmic lens to promote sustained drug release has been thoroughly pursued, there are still problems to be solved associated to the different alternatives. In this work, we went back to the traditional method of drug loading by soaking in the drug solution and tried to optimize the release profiles by changing the temperature and the time of loading. Two materials commercially available under the names of CI26Y and Definitive 50 were chosen. CI26Y is used for intraocular lenses (IOLs) and Definitive 50 for soft contact lenses (SCLs). Three drugs were tested: an antibiotic, moxifloxacin, and two anti-inflammatories, diclofenac and ketorolac. Sustained drug release from CI26Y disks for, at least 15 days, was obtained for moxifloxacin and diclofenac increasing the loading temperature up to 60 °C or extending the loading time till two months. The sustained release of ketorolac was limited to about 8 days. In contrast, drug release from Definitive 50 disks could not be improved by changing the loading conditions. An attempt to interpret the impact of the loading conditions on the drug release behavior was done using solid-state NMR and differential scanning calorimetry. These studies suggested the establishment of reversible, endothermic interactions between CI26Y and the drugs, moxifloxacin and diclofenac. The loading temperature had a slight effect on the mechanical and optical properties of drug loaded CI26Y samples, which still kept adequate properties to be used as IOL materials. The in vivo efficacy of CI26Y samples, drug loaded at 60 °C for two weeks, was predicted using a simplified mathematical model to estimate the drug concentration in the aqueous humor. The estimated concentrations were found to comply with the therapeutic needs, at least, for moxifloxacin and diclofenac. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of changes in nutrient loading and composition on hypoxia dynamics and internal nutrient cycling of a stratified coastal lagoon

NASA Astrophysics Data System (ADS)

Zhu, Yafei; McCowan, Andrew; Cook, Perran L. M.

2017-10-01

The effects of changes in catchment nutrient loading and composition on the phytoplankton dynamics, development of hypoxia and internal nutrient dynamics in a stratified coastal lagoon system (the Gippsland Lakes) were investigated using a 3-D coupled hydrodynamic biogeochemical water quality model. The study showed that primary production was equally sensitive to changed dissolved inorganic and particulate organic nitrogen loads, highlighting the need for a better understanding of particulate organic matter bioavailability. Stratification and sediment carbon enrichment were the main drivers for the hypoxia and subsequent sediment phosphorus release in Lake King. High primary production stimulated by large nitrogen loading brought on by a winter flood contributed almost all the sediment carbon deposition (as opposed to catchment loads), which was ultimately responsible for summer bottom-water hypoxia. Interestingly, internal recycling of phosphorus was more sensitive to changed nitrogen loads than total phosphorus loads, highlighting the potential importance of nitrogen loads exerting a control over systems that become phosphorus limited (such as during summer nitrogen-fixing blooms of cyanobacteria). Therefore, the current study highlighted the need to reduce both total nitrogen and total phosphorus for water quality improvement in estuarine systems.

Electrically-Assisted Turbocharger Development for Performance and Emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, Milton

2000-08-20

Turbocharger transient lag inherently imposes a tradeoff between a robust engine response to transient load shifts and exhaust emissions. By itself, a well matched turbocharger for an engine has limited flexibility in improving this transient response. Electrically-assisted turbocharging has been seen as an attractive option to improve response and lower transient emissions. This paper presents the results of a multi-year joint CRADA between DDC and ORNL. Virtual lab diesel simulation models characterized the performance improvement potential of an electrically assisted turbocharger technology. Operating requirements to reduce transient duration between load shift time by up to 50% were determined. A turbomachinemore » has been conceptualized with an integrated motor-generator, providing transient burst boost plus energy recovery capability. Numerous electric motor designs were considered, and a prototype motor was developed, fabricated, and is undergoing tests. Power controls have been designed and fabricated.« less

Refractory of Furnaces to Reduce Environmental Impact

NASA Astrophysics Data System (ADS)

Hanzawa, Shigeru

2011-10-01

The energy load of furnaces used in the manufacturing process of ceramics is quite large. Most of the environmental impact of ceramics manufacturing is due to the CO2 produced from this high energy load. To improve this situation, R&D has focused on furnace systems and techniques of control in order to reduce energy load. Since furnaces are comprised of refractory, consideration of their mechanical and thermal characteristics is important. Herein are described several refractory types which were chosen through comparison of the characteristics which contribute to heat capacity reduction, heat insulating reinforcement and high emissivity, thereby improving thermal radiation heat transfer efficiency to the ceramic articles. One selected refractory material which will reduce the environmental impact of a furnace, chosen considering low heat capacity and high emissivity characteristics, is SiC. In this study, thermal radiation heat transfer efficiency improvement and its effect on ceramic articles in the furnace and oxidation behaviour were investigated at 1700K. A high density SiC refractory, built into the furnace at construction, has relatively high oxidation durability and has the ability to reduce environmental impact-CO2 by 10 percent by decreasing the furnace's energy load. However, new oxidation prevention techniques for SiC will be necessary for long-term use in industrial furnaces, because passive to active oxidation transition behaviour of commercial SiC refractory is coming to close ideal.

Improvements to information management systems simulator

NASA Technical Reports Server (NTRS)

Bilek, R. W.

1972-01-01

The performance of personnel in the augmentation and improvement of the interactive IMSIM information management simulation model is summarized. With this augmented model, NASA now has even greater capabilities for the simulation of computer system configurations, data processing loads imposed on these configurations, and executive software to control system operations. Through these simulations, NASA has an extremely cost effective capability for the design and analysis of computer-based data management systems.

Supervision strategies for improved reliability of bus routes. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1991-09-01

The synthesis will be of interest to transit agency managers and supervisors, as well as to operating and planning personnel who are concerned with the reliability and scheduling of buses. Information is provided on service monitoring, service supervision and control, and supervision strategies. Reliability of transit service is critical to bus transit ridership. The extent of service supervision has an important bearing on reliability. The report describes the various procedures that are used by transit agencies to monitor and maintain bus service reliability. Most transit systems conduct checks of the number of riders at maximum load points and monitor schedulemore » adherence at these locations. Other supervisory actions include service restoration techniques, and strategies such as schedule control, headway control, load control, extraboard management, and personnel selection and training. More sophisticated technologies, such as automatic passenger counting (APC) systems and automatic vehicle location and control (AVLC), have been employed by some transit agencies and are described in the synthesis.« less

Advanced Software for Analysis of High-Speed Rolling-Element Bearings

NASA Technical Reports Server (NTRS)

Poplawski, J. V.; Rumbarger, J. H.; Peters, S. M.; Galatis, H.; Flower, R.

2003-01-01

COBRA-AHS is a package of advanced software for analysis of rigid or flexible shaft systems supported by rolling-element bearings operating at high speeds under complex mechanical and thermal loads. These loads can include centrifugal and thermal loads generated by motions of bearing components. COBRA-AHS offers several improvements over prior commercial bearing-analysis programs: It includes innovative probabilistic fatigue-life-estimating software that provides for computation of three-dimensional stress fields and incorporates stress-based (in contradistinction to prior load-based) mathematical models of fatigue life. It interacts automatically with the ANSYS finite-element code to generate finite-element models for estimating distributions of temperature and temperature-induced changes in dimensions in iterative thermal/dimensional analyses: thus, for example, it can be used to predict changes in clearances and thermal lockup. COBRA-AHS provides an improved graphical user interface that facilitates the iterative cycle of analysis and design by providing analysis results quickly in graphical form, enabling the user to control interactive runs without leaving the program environment, and facilitating transfer of plots and printed results for inclusion in design reports. Additional features include roller-edge stress prediction and influence of shaft and housing distortion on bearing performance.

Operation and Management of Thermostatically Controlled Loads for Providing Regulation Services to Power Grids

NASA Astrophysics Data System (ADS)

Vanouni, Maziar

The notion of demand-side participation in power systems operation and control is on the verge of realization because of the advancement in the required technologies an tools like communications, smart meters, sensor networks, large data management techniques, large scale optimization method, etc. Therefore, demand-response (DR) programs can be one of the prosperous solutions to accommodate part of the increasing demand for load balancing services which is brought about by the high penetration of intermittent renewable energies in power systems. This dissertation studies different aspects of the DR programs that utilized the thermostatically controlled loads (TCLs) to provide load balancing services. The importance of TCLs among the other loads lie on their flexibility in power consumption pattern while the customer/end-user comfort is not (or minimally) impacted. Chapter 2 discussed a previously presented direct load control (DLC) to control the power consumption of aggregated TCLs. The DLC method performs a power tracking control and based on central approach where a central controller broadcasts the control command to the dispersed TCLs to toggle them on/off. The central controller receives measurement feedback from the TCLs once per couple of minutes to run a successful forecast process. The performance evaluation criteria to evaluate the load balancing service provided by the TCLs are presented. The results are discussed under different scenarios and situation. The numerical results show the proper performance of the DLC method. This DLC method is used as the control method in all the studies in this dissertation. Chapter 3 presents performance improvements for the original method in Chapter 2 by communicating two more pieces of information called forecast parameters (FPs). Communicating improves the forecast process in the DLC and hence, both performance accuracy and the amount of tear-and-wear imposed on the TCLs. Chapter 4 formulates a stochastic optimization model for a load aggregator (LA) to participate in the performance-based regulation markets (PBRM). PBRMs are the recently developed and practiced regulation market structure recommended by Federal Energy Regulatory Commission (FERC) in 2011. In PBRMs, regulation resources are paid based on both regulation capacity bids and the regulation performance including the provided mileage and the performance accuracy. In order to develop the income from the PBRM, the convention of California Independent System Operator (CAISO) is used. In the presented optimization model, the amount of tear-and-wear imposed on the TCLs are confined to prevent abrupt switching of TCLs. In Chapter 5, a two-stage reward allocation mechanism is developed for a LA recruiting TCLs for regulation service provision. The mechanism helps the LA to distribute the total reward (earned from regulation service provision) among the TCLs according to their contribution in the whole provided service. In the first stage, TCLs are prioritized based on their service provision capability. In order to do so, an index called SPCI is presented to quantify TCLs capability/flexibility and therefore, prioritize them. After prioritization TCLs a priority list is constructed in the first stage. In the second stage, a reward curve is constructed representing the functionality of the possible total reward with respect to the number top TCLs in the priority list. Then, the allocated reward to individual TCLs is calculated by applying the incremental method on the constructed reward curve. This presented reward allocation mechanism is based on the definition of maximum service capacity (MSC) for a control group including TCLs. MSC is defined and its calculation method is presented before discussing the two stages of the reward allocation mechanism. The numerical results proves the suitability of the proposed prioritization method as it is observed the TCLs with higher rankings can contribute more to the total reward in comparison to the TCLs with lower rankings in the priority list.

Charging-choke circuit with a crowbar for precision control of voltage

DOEpatents

Praeg, W.F.

1975-11-25

The operation of a circuit using a charging choke to obtain dc voltages is improved by constructing the circuit to be capable of producing a higher voltage than the desired value and crowbarring the charging choke when the load voltage reaches the desired value.

Ammonia-based feedforward and feedback aeration control in activated sludge processes.

PubMed

Rieger, Leiv; Jones, Richard M; Dold, Peter L; Bott, Charles B

2014-01-01

Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio-P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia-based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.

Improving Bending Moment Measurements on Wind Turbine Blades

DOE Office of Scientific and Technical Information (OSTI.GOV)

Post, Nathan L.

Full-scale fatigue testing of wind turbine blades is conducted using resonance test techniques where the blade plus additional masses is excited at its first resonance frequency to achieve the target loading amplitude. Because there is not a direct relationship between the force applied by an actuator and the bending moment, the blade is instrumented with strain gauges that are calibrated under static loading conditions to determine the sensitivity or relationship between strain and applied moment. Then, during dynamic loading the applied moment is calculated using the strain response of the structure. A similar procedure is also used in the fieldmore » to measure in-service loads on turbine blades. Because wind turbine blades are complex twisted structures and the deflections are large, there is often significant cross-talk coupling in the sensitivity of strain gauges placed on the structure. Recent work has shown that a sensitivity matrix with nonzero cross terms must be employed to find constant results when a blade is subjected to both flap and lead-lag loading. However, even under controlled laboratory conditions, potential for errors of 3 percent or more in the measured moment exist when using the typical cross-talk matrix approach due to neglecting the influence of large deformations and torsion. This is particularly critical when considering a biaxial load as would be applied on the turbine or during a biaxial fatigue test. This presentation describes these results demonstrating errors made when performing current loads measurement practices on wind turbine blades in the lab and evaluating potential improvements using enhanced cross-talk matrix approaches and calibration procedures.« less

[Use of adipose-derived stem cells in an experimental rotator cuff fracture animal model].

PubMed

Barco, R; Encinas, C; Valencia, M; Carrascal, M T; García-Arranz, M; Antuña, S

2015-01-01

Rotator cuff repairs have shown a high level of re-ruptures. We hypothesized that the use of adipose-derived stem cells (ASC) could improve the biomechanical and histological properties of the repair. Controlled experimental study conducted on 44 BDIX rats with section and repair of the supraspinatus tendon and randomization to one of three groups: group A, no intervention (control); group B, local applications of a fibrin sealant; and group C, application of the fibrin sealant with 2 x 10(6) ASC. At 4 and 8 weeks a biomechanical and histological analysis was performed. There were no differences in load-to-failure at 4 and 8 weeks between groups. The load-to-failure did increase between week 4 and week 8. Histologically the tendon-to bone union showed a disorganized fibrovascular tissue. Group C showed a different inflammatory pattern, with less presence of neutrophils and more presence of plasma cells. The use of ASC does not improve the biomechanical or histological properties of the repair site. More studies are needed to improve techniques that enhance the healing site of the repair. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

A Summary of Revisions Applied to a Turbulence Response Analysis Method for Flexible Aircraft Configurations

NASA Technical Reports Server (NTRS)

Funk, Christie J.; Perry, Boyd, III; Silva, Walter A.; Newman, Brett

2014-01-01

A software program and associated methodology to study gust loading on aircraft exists for a classification of geometrically simplified flexible configurations. This program consists of a simple aircraft response model with two rigid and three flexible symmetric degrees-of - freedom and allows for the calculation of various airplane responses due to a discrete one-minus- cosine gust as well as continuous turbulence. Simplifications, assumptions, and opportunities for potential improvements pertaining to the existing software program are first identified, then a revised version of the original software tool is developed with improved methodology to include more complex geometries, additional excitation cases, and additional output data so as to provide a more useful and precise tool for gust load analysis. In order to improve the original software program to enhance usefulness, a wing control surface and horizontal tail control surface is added, an extended application of the discrete one-minus-cosine gust input is employed, a supplemental continuous turbulence spectrum is implemented, and a capability to animate the total vehicle deformation response to gust inputs is included. These revisions and enhancements are implemented and an analysis of the results is used to validate the modifications.

Nasal high-flow therapy reduces work of breathing compared with oxygen during sleep in COPD and smoking controls: a prospective observational study

PubMed Central

Kirkness, Jason P.; Grote, Ludger; Fricke, Kathrin; Schwartz, Alan R.; Smith, Philip; Schneider, Hartmut

2017-01-01

Patients with chronic obstructive pulmonary disease (COPD) endure excessive resistive and elastic loads leading to chronic respiratory failure. Oxygen supplementation corrects hypoxemia but is not expected to reduce mechanical loads. Nasal high-flow (NHF) therapy supports breathing by reducing dead space, but it is unclear how it affects mechanical loads of patients with COPD. The objective of this study was to compare the effects of low-flow oxygen and NHF therapy on ventilation and work of breathing (WOB) in patients with COPD and controls during sleep. Patients with COPD (n = 12) and controls (n = 6) were recruited and submitted to polysomnography to measure sleep parameters and ventilation in response to administration of oxygen and NHF. A subset of six patients also had an esophageal catheter inserted for the purpose of measuring WOB. Patients with COPD had similar minute ventilation (V̇e) but lower tidal volumes than matched controls. With oxygen, SaO2was increased and V̇e was reduced in both controls and patients with COPD, but there was an increase in transcutaneous CO2 levels. NHF produced a greater reduction in V̇e and was associated with a reduction in CO2 levels. Although NHF halved WOB, oxygen produced only a minor reduction in this parameter. We conclude that oxygen produced little change in WOB, which was associated with CO2 elevations. On the other hand, NHF produced a large reduction in V̇e and WOB with a concomitant decrease in CO2 levels. Our data indicate that NHF improves alveolar ventilation during sleep compared with oxygen and room air in patients with COPD and therefore can decrease their cost of breathing. NEW & NOTEWORTHY Nasal high-flow (NHF) therapy can support ventilation in patients with chronic obstructive pulmonary disease during sleep by decreasing the work of breathing and improving CO2 levels. On the other hand, oxygen supplementation corrects hypoxemia, but it produces only a minimal reduction in work of breathing and is associated with increased CO2 levels. Therefore, NHF can be a useful method to assist ventilation in patients with increased respiratory mechanical loads. PMID:27815367

High sulfur loading cathodes fabricated using peapodlike, large pore volume mesoporous carbon for lithium-sulfur battery.

PubMed

Li, Duo; Han, Fei; Wang, Shuai; Cheng, Fei; Sun, Qiang; Li, Wen-Cui

2013-03-01

Porous carbon materials with large pore volume are crucial in loading insulated sulfur with the purpose of achieving high performance for lithium-sulfur batteries. In our study, peapodlike mesoporous carbon with interconnected pore channels and large pore volume (4.69 cm(3) g(-1)) was synthesized and used as the matrix to fabricate carbon/sulfur (C/S) composite which served as attractive cathodes for lithium-sulfur batteries. Systematic investigation of the C/S composite reveals that the carbon matrix can hold a high but suitable sulfur loading of 84 wt %, which is beneficial for improving the bulk density in practical application. Such controllable sulfur-filling also effectively allows the volume expansion of active sulfur during Li(+) insertion. Moreover, the thin carbon walls (3-4 nm) of carbon matrix not only are able to shorten the pathway of Li(+) transfer and conduct electron to overcome the poor kinetics of sulfur cathode, but also are flexible to warrant structure stability. Importantly, the peapodlike carbon shell is beneficial to increase the electrical contact for improving electronic conductivity of active sulfur. Meanwhile, polymer modification with polypyrrole coating layer further restrains polysulfides dissolution and improves the cycle stability of carbon/sulfur composites.

A Comparison of Cognitive Bias Modification for Interpretation and Computerized Cognitive Behavior Therapy

PubMed Central

Bowler, Jennifer O.; Mackintosh, Bundy; Dunn, Barnaby D.; Mathews, Andrew; Dalgleish, Tim; Hoppitt, Laura

2012-01-01

Objective: Computerized cognitive behavioral therapy (cCBT) and cognitive bias modification for interpretation (CBM-I) both have demonstrated efficacy in alleviating social anxiety, but how they compare with each other has not been investigated. The present study tested the prediction that both interventions would reduce anxiety relative to a no-intervention comparison condition, but CBM-I would be particularly effective at modifying threat-related cognitive bias under high mental load. Method: Sixty-three primarily Caucasian adults (mean age = 22.7, SD = 5.87; 68.3% female) with high social anxiety, randomly allocated to 3 groups: CBM-I (n = 21), cCBT (n = 21), and a no-intervention control group (n = 21) provided complete data for analysis. Pre- and postintervention (4 sessions lasting 2 weeks, control participants only attended the pre–post sessions) self-report measures of anxiety, depression, attentional control, and threat-related interpretive bias were completed. In addition, interpretive bias under high versus low cognitive load was measured using the Scrambled Sentences Test. Results: Both CBM-I and cCBT groups reported significantly reduced levels of social anxiety, trait anxiety, and depression and improved attentional control, relative to the control group, with no clear superiority of either active intervention. Although both active conditions reduced negative bias on the Scrambled Sentences Test completed under mental load, CBM-I was significantly more effective at doing so. Conclusions: The results suggest that although not differing in therapeutic efficacy, CBM-I and cCBT might differ in the resilience of their effects when under mental load. PMID:22963595

Study protocol for a randomized controlled trial: tongue strengthening exercises in head and neck cancer patients, does exercise load matter?

PubMed

Van Nuffelen, Gwen; Van den Steen, Leen; Vanderveken, Olivier; Specenier, Pol; Van Laer, Carl; Van Rompaey, Diane; Guns, Cindy; Mariën, Steven; Peeters, Marc; Van de Heyning, Paul; Vanderwegen, Jan; De Bodt, Marc

2015-09-04

Reduced tongue strength is an important factor contributing to early and late dysphagia in head and neck cancer patients previously treated with chemoradiotherapy. The evidence is growing that tongue strengthening exercises can improve tongue strength and swallowing function in both healthy and dysphagic subjects. However, little is known about the impact of specific features of an exercise protocol for tongue strength on the actual outcome (strength or swallowing function). Previous research originating in the fields of sports medicine and physical rehabilitation shows that the degree of exercise load is an influential factor for increasing muscle strength in the limb skeletal muscles. Since the tongue is considered a muscular hydrostat, it remains to be proven whether the same concepts will apply. This ongoing randomized controlled trial in chemoradiotherapy-treated patients with head and neck cancer investigates the effect of three tongue strengthening exercise protocols, with different degrees of exercise load, on tongue strength and swallowing. At enrollment, 51 patients whose dysphagia is primarily related to reduced tongue strength are randomly assigned to a training schedule of 60, 80, or 100% of their maximal tongue strength. Patients are treated three times a week for 8 weeks, executing 120 repetitions of the assigned exercise once per training day. Exercise load is progressively adjusted every 2 weeks. Patients are evaluated before, during and after treatment by means of tongue strength measurements, fiber-optic endoscopic evaluation of swallowing and quality-of-life questionnaires. This randomized controlled trial is the first to systematically investigate the effect of different exercise loads in tongue strengthening exercise protocols. The results will allow the development of more efficacious protocols. Current Controlled Trials ISRCTN14447678.

A biomimetic hybrid nanoplatform for encapsulation and precisely controlled delivery of therasnostic agents

NASA Astrophysics Data System (ADS)

Wang, Hai; Agarwal, Pranay; Zhao, Shuting; Yu, Jianhua; Lu, Xiongbin; He, Xiaoming

2015-12-01

Nanoparticles have demonstrated great potential for enhancing drug delivery. However, the low drug encapsulation efficiency at high drug-to-nanoparticle feeding ratios and minimal drug loading content in nanoparticle at any feeding ratios are major hurdles to their widespread applications. Here we report a robust eukaryotic cell-like hybrid nanoplatform (EukaCell) for encapsulation of theranostic agents (doxorubicin and indocyanine green). The EukaCell consists of a phospholipid membrane, a cytoskeleton-like mesoporous silica matrix and a nucleus-like fullerene core. At high drug-to-nanoparticle feeding ratios (for example, 1:0.5), the encapsulation efficiency and loading content can be improved by 58 and 21 times, respectively, compared with conventional silica nanoparticles. Moreover, release of the encapsulated drug can be precisely controlled via dosing near infrared laser irradiation. Ultimately, the ultra-high (up to ~87%) loading content renders augmented anticancer capacity both in vitro and in vivo. Our EukaCell is valuable for drug delivery to fight against cancer and potentially other diseases.

RF power recovery feedback circulator

DOEpatents

Sharamentov, Sergey I [Bolingbrook, IL

2011-03-29

A device and method for improving the efficiency of RF systems having a Reflective Load. In the preferred embodiment, Reflected Energy from a superconducting resonator of a particle accelerator is reintroduced to the resonator after the phase of the Reflected Energy is aligned with the phase of the Supply Energy from a RF Energy Source. In one embodiment, a Circulator is used to transfer Reflected Energy from the Reflective Load into a Phase Adjuster which aligns the phase of the Reflected Energy with that of the Supply Energy. The phase-aligned energy is then combined with the Supply Energy, and reintroduced into the Reflective Load. In systems having a constant phase shift, the Phase Adjuster may be designed to shift the phase of the Reflected Energy by a constant amount using a Phase Shifter. In systems having a variety (variable) phase shifts, a Phase Shifter controlled by a phase feedback loop comprising a Phase Detector and a Feedback Controller to account for the various phase shifts is preferable.

Impaired acid neutralization in the duodenum in pancreatic insufficiency.

PubMed

Dutta, S K; Russell, R M; Iber, F L

1979-10-01

The influence of severe exocrine pancreatic disease on the acid-neutralizing capacity of the duodenum was studied in five patients with pancreatic insufficiency (PI) and six control subjects using duodenal perfusion-marker technique. Hydrochloric acid (0.1 N containing 1% PEG) was infused at constant rates (1.2, 4.5 and 7.0 ml/min) into the duodenum just distal to the duodenal bulb. Samples were aspirated from the tip of the duodenal perfusion tube located at the ligament of Treitz. All samples were analyzed for volume, pH, titrable acidity, PEG and [14C]PEG (gastric marker) determination. Patients with PI demonstrated significantly diminished ability to neutralize various acid loads as compared to controls who virtually completely neutralized acid loads in the range of maximal gastric acid secretion. Exogenous secretin did not significantly improve percent acid neutralized in PI. These data clearly indicate that patients with PI have significantly impaired ability to neutralize even small loads of acid in the duodenum.

Aeroservoelastic wind-tunnel investigations using the Active Flexible Wing Model: Status and recent accomplishments

NASA Technical Reports Server (NTRS)

Noll, Thomas E.; Perry, Boyd, III; Tiffany, Sherwood H.; Cole, Stanley R.; Buttrill, Carey S.; Adams, William M., Jr.; Houck, Jacob A.; Srinathkumar, S.; Mukhopadhyay, Vivek; Pototzky, Anthony S.

1989-01-01

The status of the joint NASA/Rockwell Active Flexible Wing Wind-Tunnel Test Program is described. The objectives are to develop and validate the analysis, design, and test methodologies required to apply multifunction active control technology for improving aircraft performance and stability. Major tasks include designing digital multi-input/multi-output flutter-suppression and rolling-maneuver-load alleviation concepts for a flexible full-span wind-tunnel model, obtaining an experimental data base for the basic model and each control concept and providing comparisons between experimental and analytical results to validate the methodologies. The opportunity is provided to improve real-time simulation techniques and to gain practical experience with digital control law implementation procedures.

Effect of metoprolol administration on renal sodium handling in experimental congestive heart failure.

PubMed

DiBona, G F; Sawin, L L

1999-07-06

Long-term metoprolol therapy improves cardiac performance and decreases mortality in patients with chronic congestive heart failure (CHF). This study examined the effect of long-term metoprolol therapy on renal sodium handling in an experimental rat model of CHF. Rats with left coronary ligation and myocardial infarction-induced CHF were treated with metoprolol (1.5 mg. kg-1. h-1) or vehicle for 3 weeks by osmotic minipump. They were then evaluated for their ability to excrete a short-term sodium load (5% body weight isotonic saline infusion over 30 minutes) and a long-term sodium load (change from low- to high-sodium diet over 8 days). All CHF rats had left ventricular end-diastolic pressure >10 mm Hg, and heart weight/body weight ratios averaged 0.68+/-0.02% (versus control of approximately 0.40%). Compared with vehicle CHF rats (n=19), metoprolol CHF rats (n=18) had lower basal values of mean arterial pressure (122+/-3 versus 112+/-3 mm Hg) and heart rate (373+/-14 versus 315+/-9 bpm) and decreased heart rate responses to intravenous doses of isoproterenol. During short-term isotonic saline volume loading, metoprolol CHF rats excreted 54+/-4% more of the sodium load than vehicle CHF rats. During long-term dietary sodium loading, metoprolol CHF rats retained 28+/-3% less sodium than vehicle CHF rats. Metoprolol treatment of rats with CHF results in an improved ability to excrete both short- and long-term sodium loads.

Increased resistance during jump exercise does not enhance cortical bone formation.

PubMed

Boudreaux, Ramon D; Swift, Joshua M; Gasier, Heath G; Wiggs, Michael P; Hogan, Harry A; Fluckey, James D; Bloomfield, Susan A

2014-01-01

This study sought to elucidate the effects of a low- and high-load jump resistance exercise (RE) training protocol on cortical bone of the tibia and femur mid-diaphyses. Sprague-Dawley rats (male, 6 months old) were randomly assigned to high-load RE (HRE; n = 16), low-load RE (LRE; n = 15), or cage control (CC; n = 11) groups. Animals in the HRE and LRE groups performed 15 sessions of jump RE for 5 wk. Load in the HRE group was progressively increased from 80 g added to a weighted vest (50 repetitions) to 410 g (16 repetitions). The LRE rats completed the same protocol as the HRE group (same number of repetitions), with only a 30-g vest applied. Low- and high-load jump RE resulted in 6%-11% higher cortical bone mineral content and cortical bone area compared with controls, as determined by in vivo peripheral quantitative computed tomography measurements. In the femur, however, only LRE demonstrated improvements in cortical volumetric bone mineral density (+11%) and cross-sectional moment of inertia (+20%) versus the CC group. The three-point bending to failure revealed a marked increase in tibial maximum force (25%-29%), stiffness (19%-22%), and energy to maximum force (35%-55%) and a reduction in elastic modulus (-11% to 14%) in both LRE and HRE compared with controls. Dynamic histomorphometry assessed at the tibia mid-diaphysis determined that both LRE and HRE resulted in 20%-30% higher periosteal mineralizing surface versus the CC group. Mineral apposition rate and bone formation rate were significantly greater in animals in the LRE group (27%, 39%) than those in the HRE group. These data demonstrate that jump training with minimal loading is equally, and sometimes more, effective at augmenting cortical bone integrity compared with overload training in skeletally mature rats.

Mitigation of bone loss with ultrasound induced dynamic mechanical signals in an OVX induced rat model of osteopenia.

PubMed

Ferreri, Suzanne L; Talish, Roger; Trandafir, Titi; Qin, Yi-Xian

2011-05-01

This study tests the hypothesis that an ultrasound generated dynamic mechanical signal can attenuate bone loss in an estrogen deficient model of osteopenia. Eighty-four 16-week-old Sprague-Dawley rats were divided into six groups: baseline control, age-matched control, ovariectomy (OVX) control, OVX+5mW/cm(2) ultrasound (US), OVX+30mW/cm(2) US and OVX+100mW/cm(2) US. Low intensity pulsed ultrasound (LIPUS) was delivered transdermally at the L4/L5 vertebrae, using gel-coupled plane wave US transducers. The signal, characterized by 200μs pulses of 1.5MHz sine waves repeating at 1kHz with spatial-averaged temporal-averaged (SATA) intensities of 5, 30 or 100mW/cm(2), was applied 20 min/day, 5 days/week for 4 weeks. OVX treatment reduced bone volume fraction 40% and compromised microstructure at 4 weeks. LIPUS treatment, however, significantly increased BV/TV (+33%) compared to OVX controls for the 100mW/cm(2) treated group. SMI and Tb.N showed significant improvements compared with OVX for the 100mW/cm(2) treated group and Tb.Th was significantly improved in the 30 and 100mW/cm(2) treated groups. Improvements in bone's microstructural characteristics with 100mW/cm(2) US treatment translated into improved load bearing characteristics, including a significant 42% increase in apparent level elastic modulus compared to OVX controls. Significant improvement of trabecular mechanical strength was also observed in the treated animals, e.g., principal compressive stress (represent bone's ability to resist loads) was significantly higher compared to OVX controls. Histomorphometric analysis also showed that treatment with 100mW/cm(2) US resulted in a 76% improvement in MS/BS. In addition, measures of bone quantity and quality at the femoral metaphysis suggest that LIPUS is site specific. This study indicates that localized ultrasound treatment, delivered at specific intensities, has beneficial effects on intact bone and may represent a novel intervention for bone loss. Copyright © 2011 Elsevier Inc. All rights reserved.

Mitigation of Bone Loss with Ultrasound Induced Dynamic Mechanical Signals in an OVX Induced Rat Model of Osteopenia

PubMed Central

Ferreri, Suzanne L.; Talish, Roger; Trandafir, Titi; Qin, Yi-Xian

2011-01-01

This study tests the hypothesis that an ultrasound generated dynamic mechanical signal can attenuate bone loss in an estrogen deficient model of osteopenia. Eighty-four, sixteen week old Sprague-Dawley rats were divided into six groups: baseline control, age-matched control, ovariectomy (OVX) OVX control, OVX + 5 mW/cm2 ultrasound (US), OVX + 30 mW/cm2 US and OVX + 100 mW/cm2 US. Low intensity pulsed ultrasound (LIPUS) was delivered transdermally at the L4/L5 vertebrae, using gelcoupled plane wave US transducers. The signal, characterized by 200μs pulses of 1.5 MHz sine waves repeating at 1 kHz with spatial-averaged temporal-averaged (SATA) intensities of 5, 30 or 100mW/cm2, was applied 20 min/day, 5 days/week for 4 weeks. OVX treatment reduced bone volume fraction 40% and compromised microstructure at 4 weeks. LIPUS treatment, however, significantly increased BV/TV 33% compared to OVX controls for the 100mW/cm2 treated group. SMI, and Tb.N showed significant improvements compared with OVX for the 100mW/cm2 treated group and Tb.Th was significantly improved in the 30 and 100mW/cm2 treated groups. Improvements in bone’s microstructural characteristics with 100mW/cm2 US treatment translated into improved load bearing characteristics, including a significant, 42% increase in apparent level Elastic Modulus compared to OVX controls. Significant improvement of trabecular mechanical strength is also observed in the treated animals, e.g., principal compressive stress (represent bone’s ability to resist loads) was significantly higher compared to OVX controls. Histomorphometric analysis also showed that treatment with 100mW/cm2 US resulted in a 76% improvement in MS/BS. In addition, measures of bone quantity and quality at the femoral metaphysis suggest that LIPUS is site specific. This study indicates that ultrasound, delivered at specific intensities, has beneficial effects on intact bone and may represent a novel intervention for bone loss. PMID:21241838

Residual thermal stress control in composite reinforced metal structures. [by mechanical loading of metal component prior to bonding

NASA Technical Reports Server (NTRS)

Kelly, J. B.; June, R. R.

1972-01-01

Advanced composite materials, composed of boron or graphite fibers and a supporting matrix, make significant structural efficiency improvements available to aircraft and aerospace designers. Residual stress induced during bonding of composite reinforcement to metal structural elements can be reduced or eliminated through suitable modification to the manufacturing processes. The most successful method employed during this program used a steel tool capable of mechanically loading the metal component in compression prior to the adhesive bonding cycle. Compression loading combined with heating to 350 F during the bond cycle can result in creep deformation in aluminum components. The magnitude of the deformation increases with increasing stress level during exposure to 350 F.

RMS active damping augmentation

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.; Scott, Michael A.; Demeo, Martha E.

1992-01-01

The topics are presented in viewgraph form and include: RMS active damping augmentation; potential space station assembly benefits to CSI; LaRC/JSC bridge program; control law design process; draper RMS simulator; MIMO acceleration control laws improve damping; potential load reduction benefit; DRS modified to model distributed accelerations; accelerometer location; Space Shuttle aft cockpit simulator; simulated shuttle video displays; SES test goals and objectives; and SES modifications to support RMS active damping augmentation.

Improving Legacy Aircraft Systems Through Condition-Based Maintenance: An H-60 Case Study

DTIC Science & Technology

2014-09-01

level functions. These decompositions are equivalent to a detailed design effort in systems engineering. NAMPSOPs have a common architectural structure...Assembly Power Available Spindle Cables No.1 Engine Load Demand Spindle Control Cables Engine Pneumatic Starters Auxiliary Power Unit IRCM FLIR Mission...Analysis Fuel System Main Rotor Head Main Module Main Gear Box Radiator Engine Output Shaft Auxiliary Power Unit Flight Control Cables Tail Landing

Anisotropic piezoelectric twist actuation of helicopter rotor blades: Aeroelastic analysis and design optimization

NASA Astrophysics Data System (ADS)

Wilkie, William Keats

1997-12-01

An aeroelastic model suitable for control law and preliminary structural design of composite helicopter rotor blades incorporating embedded anisotropic piezoelectric actuator laminae is developed. The aeroelasticity model consists of a linear, nonuniform beam representation of the blade structure, including linear piezoelectric actuation terms, coupled with a nonlinear, finite-state unsteady aerodynamics model. A Galerkin procedure and numerical integration in the time domain are used to obtain a soluti An aeroelastic model suitable for control law and preliminary structural design of composite helicopter rotor blades incorporating embedded anisotropic piezoelectric actuator laminae is developed. The aeroelasticity model consists of a linear, nonuniform beam representation of the blade structure, including linear piezoelectric actuation terms, coupled with a nonlinear, finite-state unsteady aerodynamics model. A Galerkin procedure and numerical integration in the time domain are used to obtain amited additional piezoelectric material mass, it is shown that blade twist actuation approaches which exploit in-plane piezoelectric free-stain anisotropies are capable of producing amplitudes of oscillatory blade twisting sufficient for rotor vibration reduction applications. The second study examines the effectiveness of using embedded piezoelectric actuator laminae to alleviate vibratory loads due to retreating blade stall. A 10 to 15 percent improvement in dynamic stall limited forward flight speed, and a 5 percent improvement in stall limited rotor thrust were numerically demonstrated for the active twist rotor blade relative to a conventional blade design. The active twist blades are also demonstrated to be more susceptible than the conventional blades to dynamic stall induced vibratory loads when not operating with twist actuation. This is the result of designing the active twist blades with low torsional stiffness in order to maximize piezoelectric twist authority. Determining the optimum tradeoff between blade torsional stiffness and piezoelectric twist actuation authority is the subject of the third study. For this investigation, a linearized hovering-flight eigenvalue analysis is developed. Linear optimal control theory is then utilized to develop an optimum active twist blade design in terms of reducing structural energy and control effort cost. The forward flight vibratory loads characteristics of the torsional stiffness optimized active twist blade are then examined using the nonlinear, forward flight aeroelastic analysis. The optimized active twist rotor blade is shown to have improved passive and active vibratory loads characteristics relative to the baseline active twist blades.

Water quality functions of riparian forest buffers in Chesapeake bay watersheds

USGS Publications Warehouse

Lowrance, R.; Altier, L.S.; Newbold, J.D.; Schnabel, R.R.; Groffman, P.M.; Denver, J.M.; Correll, D.L.; Gilliam, J.W.; Robinson, J.L.; Brinsfield, R.B.; Staver, K.W.; Lucas, W.; Todd, A.H.

1997-01-01

Maryland, Virginia, and Pennsylvania, USA, have agreed to reduce nutrient loadings to Chesapeake Bay by 40% by the year 2000. This requires control of nonpoint sources of nutrients much of which comes from agriculture. Riparian forest buffer systems (RFBS) provide effective control of nonpoint source (NPS) pollution in some types of agricultural watersheds. Control of NPS pollution is dependent on the type of pollutant and the hydrologic connection between pollution sources, the RFBS, and the stream. Water quality improvements are most likely in areas of where most of the excess precipitation moves across, in, or near the root zone of the RFBS. In areas such as the Inner Coastal Plain and Piedmont watersheds with thin soils RFBS should retain 50%-90% of the total loading of nitrate in shallow groundwater sediment in surface runoff and total N in born surface runoff and groundwater. Retention of phosphorus is generally much less. In regions with deeper soils and/or greater regional groundwater recharge (such as parts of the Piedmont and the Valley and Ridge), RFBS water quality improvements are probably much less. The expected levels of pollutant control by RFBS are identified for each of nine physiographic provinces of the Chesapeake Bay Watershed. Issues related to of establishment sustainability, and management are also discussed.

Characterisation of bare and tannase-loaded calcium alginate beads by microscopic, thermogravimetric, FTIR and XRD analyses.

PubMed

Larosa, Claudio; Salerno, Marco; de Lima, Juliana Silva; Merijs Meri, Remo; da Silva, Milena Fernandes; de Carvalho, Luiz Bezerra; Converti, Attilio

2018-08-01

Incorporating enzymes into calcium alginate beads is an effective method to immobilise them and to preserve, at the same time, their catalytic activity. Sodium alginate was mixed with Aspergillus ficuum tannase in aqueous solution, and tannase-loaded calcium alginate beads were prepared using a simple droplet-based microfluidic system. Extensive experimental analysis was carried out to characterise the samples. Microscopic imaging revealed morphological differences between the surfaces of bare alginate matrix and tannase-loaded alginate beads. Thermal analysis allowed assessing the hydration contents of alginate and revealed the presence of tannase entrapped in the loaded beads, which was confirmed by vibrational spectroscopy. X-ray diffraction allowed us to conclude that alginate of tannase-loaded beads is not crystalline, which would make them suitable as carriers for possible controlled release. Moreover, they could be used in food applications to improve tea quality or clarify juices. Copyright © 2018 Elsevier B.V. All rights reserved.

Porous, Dexamethasone-loaded polyurethane coatings extend performance window of implantable glucose sensors in vivo.

PubMed

Vallejo-Heligon, Suzana G; Brown, Nga L; Reichert, William M; Klitzman, Bruce

2016-01-01

Continuous glucose sensors offer the promise of tight glycemic control for insulin dependent diabetics; however, utilization of such systems has been hindered by issues of tissue compatibility. Here we report on the in vivo performance of implanted glucose sensors coated with Dexamethasone-loaded (Dex-loaded) porous coatings employed to mediate the tissue-sensor interface. Two animal studies were conducted to (1) characterize the tissue modifying effects of the porous Dex-loaded coatings deployed on sensor surrogate implants and (2) investigate the effects of the same coatings on the in vivo performance of Medtronic MiniMed SOF-SENSOR™ glucose sensors. The tissue response to implants was evaluated by quantifying macrophage infiltration, blood vessel formation, and collagen density around implants. Sensor function was assessed by measuring changes in sensor sensitivity and time lag, calculating the Mean Absolute Relative Difference (MARD) for each sensor treatment, and performing functional glucose challenge test at relevant time points. Implants treated with porous Dex-loaded coatings diminished inflammation and enhanced vascularization of the tissue surrounding the implants. Functional sensors with Dex-loaded porous coatings showed enhanced sensor sensitivity over a 21-day period when compared to controls. Enhanced sensor sensitivity was accompanied with an increase in sensor signal lag and MARD score. These results indicate that Dex-loaded porous coatings were able to elicit an attenuated tissue response, and that such tissue microenvironment could be conducive towards extending the performance window of glucose sensors in vivo. In the present article, a coating to extend the functionality of implantable glucose sensors in vivo was developed. Our study showed that the delivery of an anti-inflammatory agent with the presentation of micro-sized topographical cues from coatings may lead to improved long-term glucose sensor function in vivo. We believe that improved function of sensors treated with the novel coatings was a result of the observed decreases in inflammatory cell density and increases in vessel density of the tissue adjacent to the devices. Furthermore, extending the in vivo functionality of implantable glucose sensors may lead to greater adoption of these devices by diabetic patients. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Experimental investigation of active rib stitch knitted architecture for flow control applications

NASA Astrophysics Data System (ADS)

Abel, Julianna M.; Mane, Poorna; Pascoe, Benjamin; Luntz, Jonathan; Brei, Diann

2010-04-01

Actively manipulating flow characteristics around the wing can enhance the high-lift capability and reduce drag; thereby, increasing fuel economy, improving maneuverability and operation over diverse flight conditions which enables longer, more varied missions. Active knits, a novel class of cellular structural smart material actuator architectures created by continuous, interlocked loops of stranded active material, produce distributed actuation that can actively manipulate the local surface of the aircraft wing to improve flow characteristics. Rib stitch active knits actuate normal to the surface, producing span-wise discrete periodic arrays that can withstand aerodynamic forces while supplying the necessary displacement for flow control. This paper presents a preliminary experimental investigation of the pressuredisplacement actuation performance capabilities of a rib stitch active knit based upon shape memory alloy (SMA) wire. SMA rib stitch prototypes in both individual form and in stacked and nestled architectures were experimentally tested for their quasi-static load-displacement characteristics, verifying the parallel and series relationships of the architectural configurations. The various configurations tested demonstrated the potential of active knits to generate the required level of distributed surface displacements while under aerodynamic level loads for various forms of flow control.

Cascade generalized predictive control strategy for boiler drum level.

PubMed

Xu, Min; Li, Shaoyuan; Cai, Wenjian

2005-07-01

This paper proposes a cascade model predictive control scheme for boiler drum level control. By employing generalized predictive control structures for both inner and outer loops, measured and unmeasured disturbances can be effectively rejected, and drum level at constant load is maintained. In addition, nonminimum phase characteristic and system constraints in both loops can be handled effectively by generalized predictive control algorithms. Simulation results are provided to show that cascade generalized predictive control results in better performance than that of well tuned cascade proportional integral differential controllers. The algorithm has also been implemented to control a 75-MW boiler plant, and the results show an improvement over conventional control schemes.

Decreasing nitrate-N loads to coastal ecosystems with innovative drainage management strategies in agricultural landscapes: An experimental approach

USDA-ARS?s Scientific Manuscript database

Controlled drainage in agricultural ditches contributes to a drainage management strategy with potential environmental and production benefits. Innovative drainage strategies including spatially orientated low-grade weirs show promise to significantly improve nutrient (e.g. nitrate-N) reductions by...

Systems and methods for providing power to a load based upon a control strategy

DOEpatents

Perisic, Milun; Kajouke, Lateef A; Ransom, Ray M

2013-12-24

Systems and methods are provided for an electrical system. The electrical system includes a load, an interface configured to receive a voltage from a voltage source, and a controller configured to receive the voltage from the voltage source through the interface and to provide a voltage and current to the load. Wherein, when the controller is in a constant voltage mode, the controller provides a constant voltage to the load, when the controller is in a constant current mode, the controller provides a constant current to the load, and when the controller is in a constant power mode, the controller provides a constant power to the load.

Therapeutic efficacy of intra-articular hyaluronan derivative and platelet-rich plasma in mice following axial tibial loading

PubMed Central

Duan, Xin; Sandell, Linda J.; Chinzei, Nobuaki; Holguin, Nilsson; Silva, Matthew J.; Schiavinato, Antonella

2017-01-01

Objective To investigate the therapeutic potential of intra-articular hyaluronan-derivative HYADD® 4-G and/or platelet-rich plasma (PRP) in a mouse model of non-invasive joint injury. Methods Non-invasive axial tibial loading was used to induce joint injury in 10-week-old C57BL/6J mice (n = 86). Mice underwent a single loading of either 6 Newton (N) or 9N axial tibial compression. HYADD® 4-G was injected intra-articularly at 8 mg/mL or 15 mg/mL either before or after loading with or without PRP. Phosphate-buffered-saline was injected as control. Knee joints were harvested at 5 or 56 days post-loading and prepared for micro-computed tomography scanning and subsequently processed for histology. Immunostaining was performed for aggrecan to monitor its distribution, for CD44 to monitor chondrocyte reactive changes and for COMP (cartilage oligomeric matrix protein) as an index for cartilage matrix changes related to loading and cartilage injury. TUNEL assay was performed to identify chondrocyte apoptosis. Results Loading initiated cartilage proteoglycan loss and chondrocyte apoptosis within 5 days with slowly progressive post-traumatic osteoarthritis (no cartilage degeneration, but increased synovitis and ectopic calcification after 9N loading) at 56 days. Mice treated with repeated HYADD® 4-G (15 mg/mL) or HYADD® 4-G (8 mg/mL) ± PRP or PRP alone exhibited no significant improvement in the short-term (5 days) and long-term (56 days) consequences of joint loading except for a trend for improved bone changes compared to non-loaded joints. Conclusion While we failed to show an overall effect of intra-articular delivery of hyaluronan-derivative and/or PRP in reversing/protecting the pathological events in cartilage and synovium following joint injury, some bone alterations were relatively less severe with hyaluronan-derivative at higher concentration or in association with PRP. PMID:28406954

Multifunctional PEG modified DOX loaded mesoporous silica nanoparticle@CuS nanohybrids as photo-thermal agent and thermal-triggered drug release vehicle for hepatocellular carcinoma treatment

NASA Astrophysics Data System (ADS)

Wu, Lingjie; Wu, Ming; Zeng, Yongyi; Zhang, Da; Zheng, Aixian; Liu, Xiaolong; Liu, Jingfeng

2015-01-01

The combination of a multi-therapeutic mode with a controlled fashion is a key improvement in nanomedicine. Here, we synthesized polyethylene glycol (PEG)-modified doxorubicin (DOX)-loaded mesoporous silica nanoparticle (MSN) @CuS nanohybrids as efficient drug delivery carriers, combined with photothermal therapy and chemotherapy to enhance the therapeutic efficacy on hepatocellular carcinoma (HCC). The physical properties of the nanohybrids were characterized by transmission electron microscopy (TEM), N2 adsorption and desorption experiments and by the Vis-NIR absorption spectra. The results showed that the doxorubicin could be stored in the inner pores of mesoporous silica nanoparticles; the CuS nanoparticles, which are coated on the surface of a mesoporous silica nanoparticle, could serve as efficient photothermal therapy (PTT) agents; the loaded drug release could be easily triggered by NIR irradiation. The combination of the PTT treatment with controlled chemotherapy could further enhance the cancer ablation ability compared to any of the single approaches alone. Hence, the reported PEG-modified DOX-loaded mesoporous silica nanoparticle@CuS nanohybrids might be very promising therapeutic agents for HCC treatment.

Design and Control of Hydronic Radiant Cooling Systems

NASA Astrophysics Data System (ADS)

Feng, Jingjuan

Improving energy efficiency in the Heating Ventilation and Air conditioning (HVAC) systems in buildings is critical to achieve the energy reduction in the building sector, which consumes 41% of all primary energy produced in the United States, and was responsible for nearly half of U.S. CO2 emissions. Based on a report by the New Building Institute (NBI), when HVAC systems are used, about half of the zero net energy (ZNE) buildings report using a radiant cooling/heating system, often in conjunction with ground source heat pumps. Radiant systems differ from air systems in the main heat transfer mechanism used to remove heat from a space, and in their control characteristics when responding to changes in control signals and room thermal conditions. This dissertation investigates three related design and control topics: cooling load calculations, cooling capacity estimation, and control for the heavyweight radiant systems. These three issues are fundamental to the development of accurate design/modeling tools, relevant performance testing methods, and ultimately the realization of the potential energy benefits of radiant systems. Cooling load calculations are a crucial step in designing any HVAC system. In the current standards, cooling load is defined and calculated independent of HVAC system type. In this dissertation, I present research evidence that sensible zone cooling loads for radiant systems are different from cooling loads for traditional air systems. Energy simulations, in EnergyPlus, and laboratory experiments were conducted to investigate the heat transfer dynamics in spaces conditioned by radiant and air systems. The results show that the magnitude of the cooling load difference between the two systems ranges from 7-85%, and radiant systems remove heat faster than air systems. For the experimental tested conditions, 75-82% of total heat gain was removed by radiant system during the period when the heater (simulating the heat gain) was on, while for air system, 61-63% were removed. From a heat transfer perspective, the differences are mainly because the chilled surfaces directly remove part of the radiant heat gains from a zone, thereby bypassing the time-delay effect caused by the interaction of radiant heat gain with non-active thermal mass in air systems. The major conclusions based on these findings are: 1) there are important limitations in the definition of cooling load for a mixing air system described in Chapter 18 of ASHRAE Handbook of Fundamentals when applied to radiant systems; 2) due to the obvious mismatch between how radiant heat transfer is handled in traditional cooling load calculation methods compared to its central role in radiant cooling systems, this dissertation provides improvements for the current cooling load calculation method based on the Heat Balance procedure. The Radiant Time Series method is not appropriate for radiant system applications. The findings also directly apply to the selection of space heat transfer modeling algorithms that are part of all energy modeling software. Cooling capacity estimation is another critical step in a design project. The above mentioned findings and a review of the existing methods indicates that current radiant system cooling capacity estimation methods fail to take into account incident shortwave radiation generated by solar and lighting in the calculation process. This causes a significant underestimation (up to 150% for some instances) of floor cooling capacity when solar load is dominant. Building performance simulations were conducted to verify this hypothesis and quantify the impacts of solar for different design scenarios. A new simplified method was proposed to improve the predictability of the method described in ISO 11855 when solar radiation is present. The dissertation also compares the energy and comfort benefits of the model-based predictive control (MPC) method with a fine-tuned heuristic control method when applied to a heavyweight embedded surface system. A first order dynamic model of a radiant slab system was developed for implementation in model predictive controllers. A calibrated EnergyPlus model of a typical office building in California was used as a testbed for the comparison. The results indicated that MPC is able to reduce the cooling tower energy consumption by 55% and pumping power consumption by 26%, while maintaining equivalent or even better thermal comfort conditions. In summary, the dissertation work has: (1) provided clear evidence that the fundamental heat transfer mechanisms differ between radiant and air systems. These findings have important implications for the development of accurate and reliable design and energy simulation tools; (2) developed practical design methods and guidance to aid practicing engineers who are designing radiant systems; and (3) outlined future research and design tools need to advance the state-of-knowledge and design and operating guidelines for radiant systems.

Monitor-based evaluation of pollutant load from urban stormwater runoff in Beijing.

PubMed

Liu, Y; Che, W; Li, J

2005-01-01

As a major pollutant source to urban receiving waters, the non-point source pollution from urban runoff needs to be well studied and effectively controlled. Based on monitoring data from urban runoff pollutant sources, this article describes a systematic estimation of total pollutant loads from the urban areas of Beijing. A numerical model was developed to quantify main pollutant loads of urban runoff in Beijing. A sub-procedure is involved in this method, in which the flush process influences both the quantity and quality of stormwater runoff. A statistics-based method was applied in computing the annual pollutant load as an output of the runoff. The proportions of pollutant from point-source and non-point sources were compared. This provides a scientific basis for proper environmental input assessment of urban stormwater pollution to receiving waters, improvement of infrastructure performance, implementation of urban stormwater management, and utilization of stormwater.

Plug-Load Control and Behavioral Change Research in GSA Office Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metzger, I.; Cutler, D.; Sheppy, M.

2012-10-01

The U.S. General Services Administration (GSA) owns and leases over 354 million square feet (ft2) of space in over 9,600 buildings [1]. GSA is a leader among federal agencies in aggressively pursuing energy efficiency (EE) opportunities for its facilities and installing renewable energy (RE) systems to provide heating, cooling, and power to these facilities. According to several energy assessments of GSA's buildings conducted by the National Renewable Energy Laboratory (NREL), plug-loads account for approximately 21% of the total electricity consumed within a standard GSA Region 3 office building. This study aims to provide insight on how to effectively manage plug-loadmore » energy consumption and attain higher energy and cost savings for plug-loads. As GSA improves the efficiency of its building stock, plug-loads will become an even greater portion of its energy footprint.« less

Creep-Fatigue Failure Diagnosis

PubMed Central

Holdsworth, Stuart

2015-01-01

Failure diagnosis invariably involves consideration of both associated material condition and the results of a mechanical analysis of prior operating history. This Review focuses on these aspects with particular reference to creep-fatigue failure diagnosis. Creep-fatigue cracking can be due to a spectrum of loading conditions ranging from pure cyclic to mainly steady loading with infrequent off-load transients. These require a range of mechanical analysis approaches, a number of which are reviewed. The microstructural information revealing material condition can vary with alloy class. In practice, the detail of the consequent cracking mechanism(s) can be camouflaged by oxidation at high temperatures, although the presence of oxide on fracture surfaces can be used to date events leading to failure. Routine laboratory specimen post-test examination is strongly recommended to characterise the detail of deformation and damage accumulation under known and well-controlled loading conditions to improve the effectiveness and efficiency of failure diagnosis. PMID:28793676

Smith predictor with sliding mode control for processes with large dead times

NASA Astrophysics Data System (ADS)

Mehta, Utkal; Kaya, İbrahim

2017-11-01

The paper discusses the Smith Predictor scheme with Sliding Mode Controller (SP-SMC) for processes with large dead times. This technique gives improved load-disturbance rejection with optimum input control signal variations. A power rate reaching law is incorporated in the sporadic part of sliding mode control such that the overall performance recovers meaningfully. The proposed scheme obtains parameter values by satisfying a new performance index which is based on biobjective constraint. In simulation study, the efficiency of the method is evaluated for robustness and transient performance over reported techniques.

On Per-Phase Topology Control and Switching in Emerging Distribution Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mousavi, Mirrasoul J.

This paper presents a new concept and approach for topology control and switching in distribution systems by extending the traditional circuit switching to laterals and single-phase loads. Voltage unbalance and other key performance indicators including voltage magnitudes, line loading, and energy losses are used to characterize and demonstrate the technical value of optimizing system topology on a per-phase basis in response to feeder conditions. The near-optimal per-phase topology control is defined as a series of hierarchical optimization problems. The proposed approach is respectively applied to IEEE 13-bus and 123-bus test systems for demonstration, which included the impact of integrating electricmore » vehicles (EVs) in the test circuit. It is concluded that the proposed approach can be effectively leveraged to improve voltage profiles with electric vehicles, the extent of which depends upon the performance of the base case without EVs.« less

Survey of Applications of Active Control Technology for Gust Alleviation and New Challenges for Lighter-weight Aircraft

NASA Technical Reports Server (NTRS)

Regan, Christopher D.; Jutte, Christine V.

2012-01-01

This report provides a historical survey and assessment of the state of the art in the modeling and application of active control to aircraft encountering atmospheric disturbances in flight. Particular emphasis is placed on applications of active control technologies that enable weight reduction in aircraft by mitigating the effects of atmospheric disturbances. Based on what has been learned to date, recommendations are made for addressing gust alleviation on as the trend for more structurally efficient aircraft yields both lighter and more flexible aircraft. These lighter more flexible aircraft face two significant challenges reduced separation between rigid body and flexible modes, and increased sensitivity to gust encounters due to increased wing loading and improved lift to drag ratios. The primary audience of this paper is engineering professionals new to the area of gust load alleviation and interested in tackling the multifaceted challenges that lie ahead for lighter-weight aircraft.

Improving generalized inverted index lock wait times

NASA Astrophysics Data System (ADS)

Borodin, A.; Mirvoda, S.; Porshnev, S.; Ponomareva, O.

2018-01-01

Concurrent operations on tree like data structures is a cornerstone of any database system. Concurrent operations intended for improving read\\write performance and usually implemented via some way of locking. Deadlock-free methods of concurrency control are known as tree locking protocols. These protocols provide basic operations(verbs) and algorithm (ways of operation invocations) for applying it to any tree-like data structure. These algorithms operate on data, managed by storage engine which are very different among RDBMS implementations. In this paper, we discuss tree locking protocol implementation for General inverted index (Gin) applied to multiversion concurrency control (MVCC) storage engine inside PostgreSQL RDBMS. After that we introduce improvements to locking protocol and provide usage statistics about evaluation of our improvement in very high load environment in one of the world’s largest IT company.

An improved method for determining force balance calibration accuracy

NASA Technical Reports Server (NTRS)

Ferris, Alice T.

1993-01-01

The results of an improved statistical method used at Langley Research Center for determining and stating the accuracy of a force balance calibration are presented. The application of the method for initial loads, initial load determination, auxiliary loads, primary loads, and proof loads is described. The data analysis is briefly addressed.

Relationship between leg extensor muscle strength and knee joint loading during gait before and after total knee arthroplasty.

PubMed

Vahtrik, Doris; Gapeyeva, Helena; Ereline, Jaan; Pääsuke, Mati

2014-01-01

The aim of the present study was to evaluate an isometric maximal voluntary contraction (MVC) force of the leg extensor muscles and its relationship with knee joint loading during gait prior and after total knee arthroplasty (TKA). Custom-made dynamometer was used to assess an isometric MVC force of the leg extensor muscles and 3-D motion analysis system was used to evaluate the knee joint loading during gait in 13 female patients (aged 49-68 years) with knee osteoarthritis. Patients were evaluated one day before, and three and six months following TKA in the operated and non-operated leg. Six months after TKA, MVC force of the leg extensor muscles for the operated leg did not differ significantly as compared to the preoperative level, whereas it remained significantly lower for the non-operated leg and controls. The knee flexion moment and the knee joint power during mid stance of gait was improved six months after TKA, remaining significantly lowered compared with controls. Negative moderate correlation between leg extensor muscles strength and knee joint loading for the operated leg during mid stance was noted three months after TKA. The correlation analysis indicates that due to weak leg extensor muscles, an excessive load is applied to knee joint during mid stance of gait in patients, whereas in healthy subjects stronger knee-surrounding muscles provide stronger knee joint loading during gait. III (correlational study). Copyright © 2013 Elsevier B.V. All rights reserved.

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao Lin; Sun Jihong, E-mail: jhsun@bjut.edu.cn; Li Yuzhen

The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N{sub 2} adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation f{sub t}=kt{sup n} was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing andmore » therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties. - Graphical abstract: Loading (A) and release profiles (B) of aspirin in N-BMMs and N-MCM-41 indicated that BMMs have more drug loading capacity and faster release rate than that MCM-41. Highlights: > Bimodal mesoporous silicas (BMMs) and MCM-41 modified with amino group via post-treatment procedure. > Loading and release profiles of aspirin in modified BMMs and MCM-41. > Modified BMMs have more drug loading capacity and faster release rate than that modified MCM-41.« less

Prime-boost vaccination using DNA and whole inactivated virus vaccines provides limited protection against virulent feline immunodeficiency virus.

PubMed

Dunham, Stephen P; Bruce, Jennifer; Klein, Dieter; Flynn, J Norman; Golder, Matthew C; MacDonald, Susan; Jarrett, Oswald; Neil, James C

2006-11-30

Protection against feline immunodeficiency virus (FIV) has been achieved using a variety of vaccines notably whole inactivated virus (WIV) and DNA. However protection against more virulent isolates, typical of those encountered in natural infections, has been difficult to achieve. In an attempt to improve protection against virulent FIV(GL8), we combined both DNA and WIV vaccines in a "prime-boost" approach. Thirty cats were divided into four groups receiving vaccinations and one unvaccinated control group. Following viral challenge, two vaccinated animals, one receiving DNA alone and one the prime-boost vaccine remained free of viraemia, whilst all controls became viraemic. Animals vaccinated with WIV showed apparent early enhancement of infection at 2 weeks post challenge (pc) with higher plasma viral RNA loads than control animals or cats immunised with DNA alone. Despite this, animals vaccinated with WIV or DNA alone showed significantly lower proviral loads in peripheral blood mononuclear cells and mesenteric lymph node cells, whilst those receiving the DNA-WIV prime-boost vaccine showed significantly lower proviral loads in PBMC, than control animals, at 35 weeks pc. Therefore both DNA and WIV vaccines conferred limited protection against viral challenge but the combination of WIV and DNA in a prime-boost approach appeared to offer no significant advantage over either vaccine alone.

Independent Blade Pitch Controller Design for a Three-Bladed Turbine Using Disturbance Accommodating Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Na; Wright, Alan D.; Johnson, Kathryn E.

Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) algorithm are designed for the three-bladed Controls Advanced Research Turbine to regulate rotor speed and to mitigate blade root flapwise bending loads in above-rated wind speed. One of the DAC-based IPCs is designed based on a transformed symmetrical-asymmetrical (TSA) turbine model, with wind disturbances being modeled as a collective horizontal component and an asymmetrical linear shear component. Another DAC-based IPC is designed based on a multiblade coordinate (MBC) transformed turbine model, with a horizontal component and a vertical shear component being modeled as step waveform disturbance. Both ofmore » the DAC-based IPCs are found via a regulation equation solved by Kronecker product. Actuator dynamics are considered in the design processes to compensate for actuator phase delay. The simulation study shows the effectiveness of the proposed DAC-based IPCs compared to a proportional-integral (PI) collective pitch controller (CPC). Improvement on rotor speed regulation and once-per-revolution and twice-per-revolution load reductions has been observed in the proposed IPC designs.« less

Independent Blade Pitch Controller Design for a Three-Bladed Turbine Using Disturbance Accommodating Control: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Na; Wright, Alan D.; Johnson, Kathryn E.

Two independent pitch controllers (IPCs) based on the disturbance accommodating control (DAC) algorithm are designed for the three-bladed Controls Advanced Research Turbine to regulate rotor speed and to mitigate blade root flapwise bending loads in above-rated wind speed. One of the DAC-based IPCs is designed based on a transformed symmetrical-asymmetrical (TSA) turbine model, with wind disturbances being modeled as a collective horizontal component and an asymmetrical linear shear component. Another DAC-based IPC is designed based on a multiblade coordinate (MBC) transformed turbine model, with a horizontal component and a vertical shear component being modeled as step waveform disturbance. Both ofmore » the DAC-based IPCs are found via a regulation equation solved by Kronecker product. Actuator dynamics are considered in the design processes to compensate for actuator phase delay. The simulation study shows the effectiveness of the proposed DAC-based IPCs compared to a proportional-integral (PI) collective pitch controller (CPC). Improvement on rotor speed regulation and once-per-revolution and twice-per-revolution load reductions has been observed in the proposed IPC designs.« less

Modified Perfect Harmonics Cancellation Control of a Grid Interfaced SPV Power Generation

NASA Astrophysics Data System (ADS)

Singh, B.; Shahani, D. T.; Verma, A. K.

2015-03-01

This paper deals with a grid interfaced solar photo voltaic (SPV) power generating system with modified perfect harmonic cancellation (MPHC) control for power quality improvement in terms of mitigation of the current harmonics, power factor correction, control of point of common coupling (PCC) voltage with reactive power compensation and load balancing in a three phase distribution system. The proposed grid interfaced SPV system consists of a SPV array, a dc-dc boost converter and a voltage source converter (VSC) used for the compensation of other connected linear and nonlinear loads at PCC. The reference grid currents are estimated using MPHC method and control signals are derived by using pulse width modulation (PWM) current controller of VSC. The SPV power is fed to the common dc bus of VSC and dc-dc boost converter using maximum power point tracking (MPPT). The dc link voltage of VSC is regulated by using dc voltage proportional integral (PI) controller. The analysis of the proposed SPV power generating system is carried out under dc/ac short circuit and severe SPV-SX and SPV-TX intrusion.

Effects of external loads on balance control during upright stance: experimental results and model-based predictions.

PubMed

Qu, Xingda; Nussbaum, Maury A

2009-01-01

The purpose of this study was to identify the effects of external loads on balance control during upright stance, and to examine the ability of a new balance control model to predict these effects. External loads were applied to 12 young, healthy participants, and effects on balance control were characterized by center-of-pressure (COP) based measures. Several loading conditions were studied, involving combinations of load mass (10% and 20% of individual body mass) and height (at or 15% of stature above the whole-body COM). A balance control model based on an optimal control strategy was used to predict COP time series. It was assumed that a given individual would adopt the same neural optimal control mechanisms, identified in a no-load condition, under diverse external loading conditions. With the application of external loads, COP mean velocity in the anterior-posterior direction and RMS distance in the medial-lateral direction increased 8.1% and 10.4%, respectively. Predicted COP mean velocity and RMS distance in the anterior-posterior direction also increased with external loading, by 11.1% and 2.9%, respectively. Both experimental COP data and model-based predictions provided the same general conclusion, that application of larger external loads and loads more superior to the whole body center of mass lead to less effective postural control and perhaps a greater risk of loss of balance or falls. Thus, it can be concluded that the assumption about consistency in control mechanisms was partially supported, and it is the mechanical changes induced by external loads that primarily affect balance control.

A dual task priming investigation of right hemisphere inhibition for people with left hemisphere lesions

PubMed Central

2012-01-01

Background During normal semantic processing, the left hemisphere (LH) is suggested to restrict right hemisphere (RH) performance via interhemispheric suppression. However, a lesion in the LH or the use of concurrent tasks to overload the LH's attentional resource balance has been reported to result in RH disinhibition with subsequent improvements in RH performance. The current study examines variations in RH semantic processing in the context of unilateral LH lesions and the manipulation of the interhemispheric processing resource balance, in order to explore the relevance of RH disinhibition to hemispheric contributions to semantic processing following a unilateral LH lesion. Methods RH disinhibition was examined for nine participants with a single LH lesion and 13 matched controls using the dual task paradigm. Hemispheric performance on a divided visual field lexical decision semantic priming task was compared over three verbal memory load conditions, of zero-, two- and six-words. Related stimuli consisted of categorically related, associatively related, and categorically and associatively related prime-target pairs. Response time and accuracy data were recorded and analyzed using linear mixed model analysis, and planned contrasts were performed to compare priming effects in both visual fields, for each of the memory load conditions. Results Control participants exhibited significant bilateral visual field priming for all related conditions (p < .05), and a LH advantage over all three memory load conditions. Participants with LH lesions exhibited an improvement in RH priming performance as memory load increased, with priming for the categorically related condition occurring only in the 2- and 6-word memory conditions. RH disinhibition was also reflected for the LH damage (LHD) group by the removal of the LH performance advantage following the introduction of the memory load conditions. Conclusions The results from the control group are consistent with suggestions of an age related hemispheric asymmetry reduction and indicate that in healthy aging compensatory bilateral activation may reduce the impact of inhibition. In comparison, the results for the LHD group indicate that following a LH lesion RH semantic processing can be manipulated and enhanced by the introduction of a verbal memory task designed to engage LH resources and allow disinhibition of RH processing. PMID:22429687

Resistance training alters the sensorimotor control of vasti muscles.

PubMed

Wong, Y M; Ng, Gabriel

2010-02-01

The present study examined and compared two modes of weight training (bodybuilding and power-lifting) on the surface EMG of vasti muscles, knee joint position sense and isometric knee extension force in 48 able-bodied subjects. Subjects were randomly allocated into either a moderate loading and repetitions (bodybuilding) training or a high loading and low repetitions (power-lifting) training, or a no training control group. Training was conducted on alternate days with individual supervision. After 8 weeks of training, subjects from both training groups showed significantly earlier EMG onset timing and higher amplitude of vastus medialis obliquus relative to vastus lateralis (p=0.005 or <0.001), and improved knee joint position sense (p<0.001), but no such changes were found in the control group. However, the changes were not significantly different (p>0.05) between the two training groups. The findings suggested that the neuromotor control of the vasti muscles could be altered by regular weight training.

An Integrated Power-Efficient Active Rectifier With Offset-Controlled High Speed Comparators for Inductively Powered Applications

PubMed Central

Lee, Hyung-Min; Ghovanloo, Maysam

2011-01-01

We present an active full-wave rectifier with offset-controlled high speed comparators in standard CMOS that provides high power conversion efficiency (PCE) in high frequency (HF) range for inductively powered devices. This rectifier provides much lower dropout voltage and far better PCE compared to the passive on-chip or off-chip rectifiers. The built-in offset-control functions in the comparators compensate for both turn-on and turn-off delays in the main rectifying switches, thus maximizing the forward current delivered to the load and minimizing the back current to improve the PCE. We have fabricated this active rectifier in a 0.5-μm 3M2P standard CMOS process, occupying 0.18 mm2 of chip area. With 3.8 V peak ac input at 13.56 MHz, the rectifier provides 3.12 V dc output to a 500 Ω load, resulting in the PCE of 80.2%, which is the highest measured at this frequency. In addition, overvoltage protection (OVP) as safety measure and built-in back telemetry capabilities have been incorporated in our design using detuning and load shift keying (LSK) techniques, respectively, and tested. PMID:22174666

Influence of surface treatment and cyclic loading on the durability of repaired all-ceramic crowns

PubMed Central

ATTIA, Ahmed

2010-01-01

Objective This study investigated the durability of repaired all-ceramic crowns after cyclic loading. Material and methods Eighty In-ceram zirconia crowns were fabricated to restore prepared maxillary premolars. Resin cement was used for cementation of crowns. Palatal cusps were removed to simulate fracture of veneering porcelain and divided into 4 groups (n = 20). Fracture site was treated before repair as follows: roughening with diamond bur, (DB); air abrasion using 50 µm Al2O3, (AA) and silica coating using Cojet system followed by silane application, (SC). Control group (CG) 20 specimens were left without fracture. Palatal cusps were repaired using composite resin. Specimens were stored in water bath at 37°C for one week. Ten specimens of each group were subjected to cyclic loading. Fracture load (N) was recorded for each specimen using a universal testing machine. Two-way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) test (α=.05) were used for statistical analysis. Results There was statistically significant difference between control and tested groups, (p<0.001). Post Hoc analysis with the Tukey HSD test showed that cyclic loading fatigue significantly decreased means fracture load of control and test groups as follows (CG, 950.4±62.6 / 872.3±87.4, P = 0.0004), (DB, 624.2 ±38 / 425.5± 31.7, P <.001), (AA, 711.5 ±15.5 / 490 ± 25.2, p <0.001) and (SC, 788.7 ± 18.1 / 610.2 ± 25.2, P <.001), while silica coating and silane application significantly increased fracture load of repaired crowns (p<0.05). Conclusion Repair of fractured Inceram zirconia crowns after chairside treatment of the fracture site by silica coating and silane application could improve longevity of repaired In-ceram zirconia crowns. PMID:20485932

The effect of integrating constructivist and evidence-based practice on baccalaureate nursing student's cognitive load and learning performance in a research course.

PubMed

Hsieh, Suh-Ing; Hsu, Li-Ling; Huang, Tzu-Hsin

2016-07-01

Baccalaureate nursing students perceive research as unattractive, doubt the value of nursing research, and do not appreciate the link of research with practice. No studies have examined students' cognitive load during an evidence-based practice research course versus a traditional research course. To assess the effect of integrating constructivist theories and evidence-based practice on student cognitive load and learning performance in a research course. A true experimental study. A Registered Nurse-to-Bachelor of Science in Nursing program. Six classes of second-year students. Students were randomly allocated to the control group (two classes) or the experimental group (two classes) using cluster randomization. The control group underwent "traditional research"; the experimental group experienced "integrating evidence-based practice into research." Instruments for outcome assessment include the Cognitive Load Scale, cognitive test, team critique paper, and qualitative feedback on course satisfaction. The between-subjects effects were compared by Analysis of Covariance. The experimental group had significantly higher mental load (8.74 vs. 7.27, p<.001), mental effort (11.07 vs. 10.07, p=.009), mental efficiency (0.33 vs. -0.31, p<.001), and research knowledge (70.61 vs. 44.92, p<.001) than the control group. The experimental group had better critique paper scores in introduction (92.80%), literature review (91.70%), and assignment requirement and writing (89.40%). Some experimental learners expressed satisfaction with learning evidence-based practice (17.78%) and critiquing a research article (7.78%). Integrating evidence-based practice into a research course not only improved the research knowledge of baccalaureate nursing students, but also increased their mental load, mental effort, and mental efficiency. Additional studies may track learners' responses to different learning systems using the developed instrument to measure the three types of cognitive load. These findings may help educators design more effective and interesting curricula for integrating research and evidence-based practice into the studies of student nurses. Copyright © 2016. Published by Elsevier Ltd.

Comparison of neuromuscular and quadriceps strengthening exercise in the treatment of varus malaligned knees with medial knee osteoarthritis: a randomised controlled trial protocol.

PubMed

Bennell, Kim L; Egerton, Thorlene; Wrigley, Tim V; Hodges, Paul W; Hunt, Michael; Roos, Ewa M; Kyriakides, Mary; Metcalf, Ben; Forbes, Andrew; Ageberg, Eva; Hinman, Rana S

2011-12-05

Osteoarthritis of the knee involving predominantly the medial tibiofemoral compartment is common in older people, giving rise to pain and loss of function. Many people experience progressive worsening of the disease over time, particularly those with varus malalignment and increased medial knee joint load. Therefore, interventions that can reduce excessive medial knee loading may be beneficial in reducing the risk of structural progression. Traditional quadriceps strengthening can improve pain and function in people with knee osteoarthritis but does not appear to reduce medial knee load. A neuromuscular exercise program, emphasising optimal alignment of the trunk and lower limb joints relative to one another, as well as quality of movement performance, while dynamically and functionally strengthening the lower limb muscles, may be able to reduce medial knee load. Such a program may also be superior to traditional quadriceps strengthening with respect to improved pain and physical function because of the functional and dynamic nature. This randomised controlled trial will investigate the effect of a neuromuscular exercise program on medial knee joint loading, pain and function in individuals with medial knee joint osteoarthritis. We hypothesise that the neuromuscular program will reduce medial knee load as well as pain and functional limitations to a greater extent than a traditional quadriceps strengthening program. 100 people with medial knee pain, radiographic medial compartment osteoarthritis and varus malalignment will be recruited and randomly allocated to one of two 12-week exercise programs: quadriceps strengthening or neuromuscular exercise. Each program will involve 14 supervised exercise sessions with a physiotherapist plus four unsupervised sessions per week at home. The primary outcomes are medial knee load during walking (the peak external knee adduction moment from 3D gait analysis), pain, and self-reported physical function measured at baseline and immediately following the program. Secondary outcomes include the external knee adduction moment angular impulse, electromyographic muscle activation patterns, knee and hip muscle strength, balance, functional ability, and quality-of-life. The findings will help determine whether neuromuscular exercise is superior to traditional quadriceps strengthening regarding effects on knee load, pain and physical function in people with medial knee osteoarthritis and varus malalignment. Australian New Zealand Clinical Trials Registry reference: ACTRN12610000660088.

Comparison of neuromuscular and quadriceps strengthening exercise in the treatment of varus malaligned knees with medial knee osteoarthritis: a randomised controlled trial protocol

PubMed Central

2011-01-01

Background Osteoarthritis of the knee involving predominantly the medial tibiofemoral compartment is common in older people, giving rise to pain and loss of function. Many people experience progressive worsening of the disease over time, particularly those with varus malalignment and increased medial knee joint load. Therefore, interventions that can reduce excessive medial knee loading may be beneficial in reducing the risk of structural progression. Traditional quadriceps strengthening can improve pain and function in people with knee osteoarthritis but does not appear to reduce medial knee load. A neuromuscular exercise program, emphasising optimal alignment of the trunk and lower limb joints relative to one another, as well as quality of movement performance, while dynamically and functionally strengthening the lower limb muscles, may be able to reduce medial knee load. Such a program may also be superior to traditional quadriceps strengthening with respect to improved pain and physical function because of the functional and dynamic nature. This randomised controlled trial will investigate the effect of a neuromuscular exercise program on medial knee joint loading, pain and function in individuals with medial knee joint osteoarthritis. We hypothesise that the neuromuscular program will reduce medial knee load as well as pain and functional limitations to a greater extent than a traditional quadriceps strengthening program. Methods/Design 100 people with medial knee pain, radiographic medial compartment osteoarthritis and varus malalignment will be recruited and randomly allocated to one of two 12-week exercise programs: quadriceps strengthening or neuromuscular exercise. Each program will involve 14 supervised exercise sessions with a physiotherapist plus four unsupervised sessions per week at home. The primary outcomes are medial knee load during walking (the peak external knee adduction moment from 3D gait analysis), pain, and self-reported physical function measured at baseline and immediately following the program. Secondary outcomes include the external knee adduction moment angular impulse, electromyographic muscle activation patterns, knee and hip muscle strength, balance, functional ability, and quality-of-life. Discussion The findings will help determine whether neuromuscular exercise is superior to traditional quadriceps strengthening regarding effects on knee load, pain and physical function in people with medial knee osteoarthritis and varus malalignment. Trial Registration Australian New Zealand Clinical Trials Registry reference: ACTRN12610000660088 PMID:22141334

14 CFR 23.395 - Control system loads.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Loads § 23.395 Control system loads. (a) Each flight control system and its supporting structure must be... at the appropriate control grips or pads as they would in flight, and to react at the attachments of... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Control system loads. 23.395 Section 23.395...

Development of drug-loaded polymer microcapsules for treatment of epilepsy.

PubMed

Chen, Yu; Gu, Qi; Yue, Zhilian; Crook, Jeremy M; Moulton, Simon E; Cook, Mark J; Wallace, Gordon G

2017-09-26

Despite significant progress in developing new drugs for seizure control, epilepsy still affects 1% of the global population and is drug-resistant in more than 30% of cases. To improve the therapeutic efficacy of epilepsy medication, a promising approach is to deliver anti-epilepsy drugs directly to affected brain areas using local drug delivery systems. The drug delivery systems must meet a number of criteria, including high drug loading efficiency, biodegradability, neuro-cytocompatibility and predictable drug release profiles. Here we report the development of fibre- and sphere-based microcapsules that exhibit controllable uniform morphologies and drug release profiles as predicted by mathematical modelling. Importantly, both forms of fabricated microcapsules are compatible with human brain derived neural stem cells and differentiated neurons and neuroglia, indicating clinical compliance for neural implantation and therapeutic drug delivery.

Assessment and Optimization of Lidar Measurement Availability for Wind Turbine Control (Poster)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scholbrock, F. A.; Fleming, P.; Wright, A.

2014-02-01

Integrating Lidar to improve wind turbine controls is a potential breakthrough for reducing the cost of wind energy. By providing undisturbed wind measurements up to 400m in front of the rotor, Lidar may provide an accurate update of the turbine inflow with a preview time of several seconds. Focusing on loads, several studies have evaluated potential reductions using integrated Lidar, either by simulation or full scale field testing.

Analyses and tests of the B-1 aircraft structural mode control system

NASA Technical Reports Server (NTRS)

Wykes, J. H.; Byar, T. R.; Macmiller, C. J.; Greek, D. C.

1980-01-01

Analyses and flight tests of the B-1 structural mode control system (SMCS) are presented. Improvements in the total dynamic response of a flexible aircraft and the benefits to ride qualities, handling qualities, crew efficiency, and reduced dynamic loads on the primary structures, were investigated. The effectiveness and the performance of the SMCS, which uses small aerodynamic surfaces at the vehicle nose to provide damping to the structural modes, were evaluated.

Greater Strength Gains after Training with Accentuated Eccentric than Traditional Isoinertial Loads in Already Strength-Trained Men

PubMed Central

Walker, Simon; Blazevich, Anthony J.; Haff, G. Gregory; Tufano, James J.; Newton, Robert U.; Häkkinen, Keijo

2016-01-01

As training experience increases it becomes more challenging to induce further neuromuscular adaptation. Consequently, strength trainers seek alternative training methods in order to further increase strength and muscle mass. One method is to utilize accentuated eccentric loading, which applies a greater external load during the eccentric phase of the lift as compared to the concentric phase. Based upon this practice, the purpose of this study was to determine the effects of 10 weeks of accentuated eccentric loading vs. traditional isoinertial resistance training in strength-trained men. Young (22 ± 3 years, 177 ± 6 cm, 76 ± 10 kg, n = 28) strength-trained men (2.6 ± 2.2 years experience) were allocated to concentric-eccentric resistance training in the form of accentuated eccentric load (eccentric load = concentric load + 40%) or traditional resistance training, while the control group continued their normal unsupervised training program. Both intervention groups performed three sets of 6-RM (session 1) and three sets of 10-RM (session 2) bilateral leg press and unilateral knee extension exercises per week. Maximum force production was measured by unilateral isometric (110° knee angle) and isokinetic (concentric and eccentric 30°.s−1) knee extension tests, and work capacity was measured by a knee extension repetition-to-failure test. Muscle mass was assessed using panoramic ultrasonography and dual-energy x-ray absorptiometry. Surface electromyogram amplitude normalized to maximum M-wave and the twitch interpolation technique were used to examine maximal muscle activation. After training, maximum isometric torque increased significantly more in the accentuated eccentric load group than control (18 ± 10 vs. 1 ± 5%, p < 0.01), which was accompanied by an increase in voluntary activation (3.5 ± 5%, p < 0.05). Isokinetic eccentric torque increased significantly after accentuated eccentric load training only (10 ± 9%, p < 0.05), whereas concentric torque increased equally in both the accentuated eccentric load (10 ± 9%, p < 0.01) and traditional (9 ± 6%, p < 0.01) resistance training groups; however, the increase in the accentuated eccentric load group was significantly greater (p < 0.05) than control (1 ± 7%). Knee extension repetition-to-failure improved in the accentuated eccentric load group only (28%, p < 0.05). Similar increases in muscle mass occurred in both intervention groups. In summary, accentuated eccentric load training led to greater increases in maximum force production, work capacity and muscle activation, but not muscle hypertrophy, in strength-trained individuals. PMID:27199764

Ground reaction force comparison of controlled resistance methods to isoinertial loading of the squat exercise - biomed 2010.

PubMed

Paulus, David C; Reynolds, Michael C; Schilling, Brian K

2010-01-01

The ground reaction force during the concentric (raising) portion of the squat exercise was compared to that of isoinertial loading (free weights) for three pneumatically controlled resistance methods: constant resistance, cam force profile, and proportional force control based on velocity. Constant force control showed lower ground reaction forces than isoinertial loading throughout the range of motion (ROM). The cam force profile exhibited slightly greater ground reaction forces than isoinertial loading at 10 and 40% ROM with fifty-percent greater loading at 70% ROM. The proportional force control consistently elicited greater ground reaction force than isoinertial loading, which progressively ranged from twenty to forty percent increase over isoinertial loading except for being approximately equal at 85% ROM. Based on these preliminary results, the proportional control shows the most promise for providing loading that is comparable in magnitude to isoinertial loading. This technology could optimize resistance exercise for sport-specific training or as a countermeasure to atrophy during spaceflight.

The 77 K operation of a multi-resonant power converter

NASA Technical Reports Server (NTRS)

Ray, Biswajit; Gerber, Scott S.; Patterson, Richard L.; Myers, Ira T.

1995-01-01

The liquid-nitrogen temperature (77 K) operation of a 55 W, 200 kHz, 48/28 V zero-voltage switching multi-resonant dc/dc converter designed with commercially available components is reported. Upon dipping the complete converter (power and control circuits) into liquid-nitrogen, the converter performance improved as compared to the room-temperature operation. The switching frequency, resonant frequency, and the characteristic impedance did not change significantly. Accordingly, the zero-voltage switching was maintained from no-load to full-load for the specified line variations. Cryoelectronics can provide high density power converters, especially for high power applications.

Supercooling Preservation Of The Rat Liver For Transplantation

PubMed Central

Bruinsma, Bote G.; Berendsen, Tim A.; Izamis, Maria-Louisa; Yeh, Heidi; Yarmush, Martin L.; Uygun, Korkut

2015-01-01

The current standard for liver preservation is limited in duration. Employing a novel subzero preservation technique that includes supercooling and machine perfusion can significantly improve preservation and prolong storage times. By loading rat livers with cryoprotectants to prevent both intra- and extracellular ice formation and protect against hypothermic injury, livers can be cooled to −6 °C without freezing and kept viable for up to 96 hours. Here, we describe the procedures of loading cryoprotectants by means of subnormothermic machine perfusion (SNMP), controlled cooling to a supercooled state, followed by SNMP recovery and orthotopic liver transplantation. PMID:25692985

[Clinical efficacy of mouse nerve growth factor in treatment of occupational hand-arm vibration disease].

PubMed

Fan, Chunyue; Wang, Yanyan; Zhang, Ying; Lang, Li; Deng, Xiaofeng; Cheng, Ying

2014-12-01

To investigate the efficacy of mouse nerve growth factor (mNGF) in treating occupational hand-arm vibration disease (HAVD). Sixty-four patients with HAVD were equally and randomly divided into treatment group and control group. The control group was given Salvia miltiorrhiza Bunge and deproteinized extract of calf blood to improve circulation, and also given methylcobalamin tablets and vitamin B6 for neurotrophic treatment. In addition to the above treatments for the control group, the treatment group was also given 30 µg/d mNGF by intramuscular injection for two courses (4 weeks for each course) with a 15-day interval. Both the treatment group and the control group showed significant improvements in clinical symptoms and signs (hand numbness and pain, and reduced senses of touch, pain, and vibration), cold water loading test (CWLT), and electroneuromyography (ENMG) after treatments (P < 0.05). And the treatment group had significantly more improvements than the control group (P < 0.05). mNGF can significantly improve hand numbness and pain, reduced senses of touch, pain, and vibration, CWLT, and ENMG, so it has better clinical effect and safety in treating HAVD. Early diagnosis and treatment can improve the outcome of patients with HAVD.

Electrostimulation improves muscle perfusion but does not affect either muscle deoxygenation or pulmonary oxygen consumption kinetics during a heavy constant-load exercise.

PubMed

Layec, Gwenael; Millet, Grégoire P; Jougla, Aurélie; Micallef, Jean-Paul; Bendahan, David

2008-02-01

Electromyostimulation (EMS) is commonly used as part of training programs. However, the exact effects at the muscle level are largely unknown and it has been recently hypothesized that the beneficial effect of EMS could be mediated by an improved muscle perfusion. In the present study, we investigated rates of changes in pulmonary oxygen consumption (VO(2p)) and muscle deoxygenation during a standardized exercise performed after an EMS warm-up session. We aimed at determining whether EMS could modify pulmonary O(2) uptake and muscle deoxygenation as a result of improved oxygen delivery. Nine subjects performed a 6-min heavy constant load cycling exercise bout preceded either by an EMS session (EMS) or under control conditions (CONT). VO(2p) and heart rate (HR) were measured while deoxy-(HHb), oxy-(HbO(2)) and total haemoglobin/myoglobin (Hb(tot)) relative contents were measured using near infrared spectroscopy. EMS significantly increased (P < 0.05) the Hb(tot) resting level illustrating a residual hyperaemia. The EMS priming exercise did not affect either the HHb time constant (17.7 +/- 14.2 s vs. 13.1 +/- 2.3 s under control conditions) or the VO(2p) kinetics (time-constant = 18.2 +/- 5.2 s vs. 15.4 +/- 4.6 s under control conditions). Likewise, the other VO(2p) parameters were unchanged. Our results further indicated that EMS warm-up improved muscle perfusion through a residual hyperaemia. However, neither VO(2p) nor [HHb] kinetics were modified accordingly. These results suggest that improved O(2) delivery by residual hyperaemia induced by EMS does not accelerate the rate of aerobic metabolism during heavy exercise at least in trained subjects.

Eight Weeks of Strength and Power Training Improves Club Head Speed in Collegiate Golfers.

PubMed

Oranchuk, Dustin J; Mannerberg, Jason M; Robinson, Tracey L; Nelson, Megan C

2018-02-14

Club head speed (CHS) is a major determinant of drive distance, a key component of golf performance. The purpose of this study was to determine the indirect effects of an eight-week strength and power program on CHS. Twelve (6 male, 6 female) NCAA Division II golfers (20.3±1.5 years) randomly assigned to an intervention or control group, underwent either a periodized strength and power program consisting of high-load barbell movements or a bodyweight and rotational movement focused resistance training program. Outcomes were CHS, countermovement jump (CMJ) height, and 1RM back squat (BS), power clean (PC), and deadlift (DL). Dependent t-tests were utilized to assess differences in outcome variables pre-to-post for each group, independent t-tests were utilized to assess differences between groups, and Pearson correlations were utilized to assess associations between CHS and outcome variables. On average, the intervention group experienced improvements in all outcome variables except peak CHS (p=0.60); the control group displayed no changes in any outcome variable except a decrease in average CHS (p=0.028). Compared to the control group, the intervention group experienced greater improvements in average CHS, BS, PC, and average and peak CMJ height (p<0.05). Additionally, CHS had large associations with PC (r=0.70, p=0.012), BS (r=0.64, p=0.025), DL (r=0.54, p=0.068) and CMJ (r=0.73, p=0.007). These results suggest improving muscular strength and power by increasing PC, BS, and CMJ is associated with increased CHS in collegiate golfers. Integrating a high-load, barbell-focused strength and power program may be beneficial for improving CHS and indirectly, golf performance.

Influences of load characteristics on impaired control of grip forces in patients with cerebellar damage.

PubMed

Brandauer, B; Timmann, D; Häusler, A; Hermsdörfer, J

2010-02-01

Various studies showed a clear impairment of cerebellar patients to modulate grip force in anticipation of the loads resulting from movements with a grasped object. This failure corroborated the theory of internal feedforward models in the cerebellum. Cerebellar damage also impairs the coordination of multiple-joint movements and this has been related to deficient prediction and compensation of movement-induced torques. To study the effects of disturbed torque control on feedforward grip-force control, two self-generated load conditions with different demands on torque control-one with movement-induced and the other with isometrically generated load changes-were directly compared in patients with cerebellar degeneration. Furthermore the cerebellum is thought to be more involved in grip-force adjustment to self-generated loads than to externally generated loads. Consequently, an additional condition with externally generated loads was introduced to further test this hypothesis. Analysis of 23 patients with degenerative cerebellar damage revealed clear impairments in predictive feedforward mechanisms in the control of both self-generated load types. Besides feedforward control, the cerebellar damage also affected more reactive responses when the externally generated load destabilized the grip, although this impairment may vary with the type of load as suggested by control experiments. The present findings provide further support that the cerebellum plays a major role in predictive control mechanisms. However, this impact of the cerebellum does not strongly depend on the nature of the load and the specific internal forward model. Contributions to reactive (grip force) control are not negligible, but seem to be dependent on the physical characteristics of an externally generated load.

Effects of squat lift training and free weight muscle training on maximum lifting load and isolinetic peak torque of young adults without impairments.

PubMed

Yeung, S S; Ng, G Y

2000-06-01

Manual lifting is a frequent cause of back injury, and there is no evidence as to which training mode can provide the best training effect for lifting performance and muscle force. The purpose of this study was to examine the effects of a squat lift training and a free weight muscle training program on the maximum lifting load and isokinetic peak torque in subjects without known neuromuscular or musculoskeletal impairments. Thirty-six adults (20 male, 16 female) without known neuromuscular or musculoskeletal impairments participated. The subjects' mean age was 21.25 years (SD=1.16, range=20-24). Subjects were divided into 3 groups. Subjects in group 1 (n=12) performed squat lift training. Subjects in group 2 (n=12) participated in free weight resistance training of their shoulder abductors, elbow flexors, knee extensors and trunk extensors. Subjects in group 3 (n=12) served as controls. The maximum lifting load and isokinetic peak torques of the trunk extensors, knee extensors, elbow flexors, and shoulder abductors of each subject were measured before and after the study. Training was conducted on alternate days for 4 weeks, with an initial load of 80% of each subject's maximum capacity and with the load increased by 5% weekly. All groups were comparable for all measured variables before the study. After 4 weeks, subjects in groups 1 and 2 demonstrated more improvement in maximum lifting load and isokinetic peak torque of the back extensors compared with the subjects in group 3, but the 2 training groups were not different. The findings demonstrate that both squat lift and free weight resistance training are equally effective in improving the lifting load and isokinetic back extension performance of individuals without impairments.

Improved approximations for control augmented structural synthesis

NASA Technical Reports Server (NTRS)

Thomas, H. L.; Schmit, L. A.

1990-01-01

A methodology for control-augmented structural synthesis is presented for structure-control systems which can be modeled as an assemblage of beam, truss, and nonstructural mass elements augmented by a noncollocated direct output feedback control system. Truss areas, beam cross sectional dimensions, nonstructural masses and rotary inertias, and controller position and velocity gains are treated simultaneously as design variables. The structural mass and a control-system performance index can be minimized simultaneously, with design constraints placed on static stresses and displacements, dynamic harmonic displacements and forces, structural frequencies, and closed-loop eigenvalues and damping ratios. Intermediate design-variable and response-quantity concepts are used to generate new approximations for displacements and actuator forces under harmonic dynamic loads and for system complex eigenvalues. This improves the overall efficiency of the procedure by reducing the number of complete analyses required for convergence. Numerical results which illustrate the effectiveness of the method are given.

Measurement of air-surface exchange of speciated nitrogen and sulfur compounds using a modified MARGA 2S: Assessment and control of data quality

EPA Science Inventory

Improved measurement methods are needed to characterize dry deposition of sulfur and nitrogen compounds to assess ecosystem exposure to nutrients and acidifying compounds and to develop atmospheric deposition budgets in support of critical loads assessments. The purpose of this ...

Experimental treatment of Curvularia infection.

PubMed

Paredes, Katihuska; Capilla, Javier; Sutton, Deanna A; Mayayo, Emilio; Fothergill, Annette W; Guarro, Josep

2014-08-01

We have evaluated the efficacy of amphotericin B, posaconazole, and voriconazole in immunosuppressed murine models of disseminated infection by Curvularia spicifera and Curvularia hawaiiensis. The 3 antifungals improved survival of mice in comparison to controls; however, only the 2 azoles were able to reduce significantly the fungal load. Copyright © 2014 Elsevier Inc. All rights reserved.

Behaviour of Epoxy Silica Nanocomposites Under Static and Creep Loading

NASA Astrophysics Data System (ADS)

Constantinescu, Dan Mihai; Picu, Radu Catalin; Sandu, Marin; Apostol, Dragos Alexandru; Sandu, Adriana; Baciu, Florin

2017-12-01

Specific manufacturing technologies were applied for the fabrication of epoxy-based nanocomposites with silica nanoparticles. For dispersing the fillers in the epoxy resin special equipment such as a shear mixer and a high energy sonicator with temperature control were used. Both functionalized and unfunctionalized silica nanoparticles were added in three epoxy resins. The considered filling fraction was in most cases 0.1, 0.3 and 0.5 wt%.. The obtained nanocomposites were subjected to monotonic uniaxial and creep loading at room temperature. The static mechanical properties were not significantly improved regardless the filler percentage and type of epoxy resin. Under creep loading, by increasing the stress level, the nanocomposite with 0.1 wt% silica creeps less than all other materials. Also the creep rate is reduced by adding silica nanofillers.

Texturing of UHMWPE surface via NIL for low friction and wear properties

NASA Astrophysics Data System (ADS)

Suryadi Kustandi, Tanu; Choo, Jian Huei; Low, Hong Yee; Sinha, Sujeet K.

2010-01-01

Wear is a major obstacle limiting the useful life of implanted ultra-high molecular weight polyethylene (UHMWPE) components in total joint arthroplasty. It has been a continuous effort in the implant industry to reduce the frictional wear problem of UHMWPE by improving the structure, morphology and mechanical properties of the polymer. In this paper, a new paradigm that utilizes nanoimprint lithography (NIL) in producing textures on the surface of UHMWPE is proposed to efficiently improve the tribological properties of the polymer. Friction and wear experiments were conducted on patterned and controlled (non-patterned) UHMWPE surfaces using a commercial tribometer, mounted with a silicon nitride ball, under a dry-sliding condition with normal loads ranging from 60 to 200 mN. It has been shown that the patterned UHMWPE surface showed a reduction in the coefficient of friction between 8% and 35% as compared with the controlled (non-patterned) surface, depending on the magnitude of the normal load. Reciprocating wear experiments also showed that the presence of surface textures on the polymer resulted in lower wear depth and width, with minimal material transfer to the sliding surface.

Deep Compaction Control of Sandy Soils

NASA Astrophysics Data System (ADS)

Bałachowski, Lech; Kurek, Norbert

2015-02-01

Vibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation of CPTU/DMT can be used to take into account vertical and horizontal stress and void ratio effects. Some examples of interpretation of soundings in pre-treated and compacted sands are given. Some acceptance criteria for compaction control are discussed. The improvement factors are analysed including the normalised approach based on the soil behaviour type index.

Computerized counseling reduces HIV-1 viral load and sexual transmission risk: findings from a randomized controlled trial.

PubMed

Kurth, Ann E; Spielberg, Freya; Cleland, Charles M; Lambdin, Barrot; Bangsberg, David R; Frick, Pamela A; Severynen, Anneleen O; Clausen, Marc; Norman, Robert G; Lockhart, David; Simoni, Jane M; Holmes, King K

2014-04-15

Evaluate a computerized intervention supporting antiretroviral therapy (ART) adherence and HIV transmission prevention. Longitudinal randomized controlled trial. An academic HIV clinic and a community-based organization in Seattle. In a total of 240 HIV-positive adults on ART, 209 completed 9-month follow-up (87% retention). Randomization to computerized counseling or assessment only, 4 sessions over 9 months. HIV-1 viral suppression, and self-reported ART adherence and transmission risks, compared using generalized estimating equations. Overall, intervention participants had reduced viral load: mean 0.17 log10 decline, versus 0.13 increase in controls, P = 0.053, and significant difference in ART adherence baseline to 9 months (P = 0.046). Their sexual transmission risk behaviors decreased (odds ratio = 0.55, P = 0.020), a reduction not seen among controls (odds ratio = 1.1, P = 0.664), and a significant difference in change (P = 0.040). Intervention effect was driven by those most in need; among those with detectable virus at baseline (>30 copies/mL, n = 89), intervention effect was mean 0.60 log10 viral load decline versus 0.15 increase in controls, P = 0.034. ART adherence at the final follow-up was 13 points higher among intervention participants versus controls, P = 0.038. Computerized counseling is promising for integrated ART adherence and safer sex, especially for individuals with problems in these areas. This is the first intervention to report improved ART adherence, viral suppression, and reduced secondary sexual transmission risk behavior.

Failure and fatigue characteristics of adhesive athletic tape.

PubMed

Bragg, Richard W; Macmahon, John M; Overom, Erin K; Yerby, Scott A; Matheson, Gordon O; Carter, Dennis R; Andriacchi, Thomas P

2002-03-01

Athletic tape has been commonly reported to lose much of its structural support after 20 min of exercise. Although many studies have addressed the functional performance characteristics of athletic tape, its mechanical properties are poorly understood. This study examines the failure and fatigue properties of several commonly used athletic tapes. A Web-based survey of professional sports trainers was used to select the following three tapes for the study: Zonas (Johnson & Johnson), Leukotape (Beiersdorf), and Jaylastic (Jaybird & Mais). Using a hydraulic material testing system (MTS), eight samples of each tape were compared in three different mechanical tests: load-to-failure, fatigue testing under load control, and fatigue testing under displacement control. Differences in tape microstructure were used to interpret the results of the mechanical tests. Significant differences (P < 0.001) in failure load, elongation at failure, and stiffness were found from failure tests. Significant differences were also found (P < 0.001) in fatigue behavior under both modes of control. As a representative example, in one normalized displacement control fatigue test after 20 min of cycling, 21% (Zonas), 29% (Leukotape), and 57% (Jaylastic) of the mechanical support was lost. After cycling, all tapes loaded to failure showed increased stiffness (P < 0.001), indicating significant energy absorption during cycling. Observed differences in the tapes' microstructure were qualitatively consistent with the measured differences in their mechanical properties. In understanding the shortcomings of currently available tapes, the results of these tests can now be used as benchmarks with which to compare and develop future tape designs. Ultimately, these improved tapes should reduce ankle injuries among athletes.

Thermally Stratified Compression Ignition: A new advanced low temperature combustion mode with load flexibility

DOE PAGES

Lawler, Benjamin; Splitter, Derek; Szybist, James; ...

2017-03-01

We introduce a new advanced combustion mode, called Thermally Stratified Compression Ignition (TSCI), which uses direct water injection to control both the average temperature and the temperature distribution prior to ignition, thereby providing cycle-to-cycle control over the start and rate of heat release in Low Temperature Combustion (LTC). Experiments were conducted to fundamentally understand the effects of water injection on heat release in LTC. Our results show that water injection retards the start of combustion due to the latent heat of vaporization of the injected water. Furthermore, for start of water injection timings between 20 and 70 degrees before topmore » dead center, combustion is significantly elongated compared to without water injection. The 10–90% burn duration with 6.6 and 9.0 mg of water per cycle was 77% and 146% longer than without water injection, respectively. Forced thermal stratification result from a direct water injection which reduces the heat release rate by local evaporative cooling. Finally, the load limits with and without water injection were determined experimentally. Without water injection, the load range was 2.3–3.6 bar gross IMEP. By using water injection to control heat release, the load range in TSCI was 2.3–8.4 bar gross IMEP, which is a range expansion of over 350%. These results demonstrate that direct water injection can provide significant improvements to both controllability and the range of operability of LTC, thereby resolving the major challenges associated with HCCI.« less

Analgesic effects of carprofen and liposome-encapsulated butorphanol tartrate in Hispaniolan parrots (Amazona ventralis) with experimentally induced arthritis.

PubMed

Paul-Murphy, Joanne R; Sladky, Kurt K; Krugner-Higby, Lisa A; Stading, Ben R; Klauer, Julia M; Keuler, Nicholas S; Brown, Carolyn S; Heath, Timothy D

2009-10-01

To evaluate the microcrystalline sodium urate (MSU) method for inducing arthritis in parrots and to compare the analgesic efficacy of long-acting liposome-encapsulated butorphanol (LEBT), carprofen, or a combination of both. 20 Hispaniolan parrots. MSU was injected into a tibiotarsal-tarsometatarsal (intertarsal) joint to induce arthritis (time 0). Four treatments were compared (LEBT [15 mg/kg, SC] administered once at time 0; injections of carprofen [3 mg/kg, IM, q 12 h] starting at time 0; administration of LEBT plus carprofen; and a control treatment of saline [0.9% NaCl] solution). Weight load testing and behavioral scoring were conducted at 0, 2, 6, 26, and 30 hours. Injection of MSU into the intertarsal joint induced arthritis, which resolved within 30 hours. Treatment with LEBT or LEBT plus carprofen resulted in significantly greater weight-bearing load on the limb with induced arthritis, compared with the control treatment. Treatment with carprofen alone caused a slight but nonsignificant improvement in weight-bearing load on the arthritic limb, compared with the control treatment. Behaviors associated with motor activity and weight bearing differed between the control and analgesic treatments. Butorphanol was an effective treatment for pain associated with arthritis, but carprofen administered every 12 hours was insufficient. Injection of MSU to induce arthritis in a single joint was a good method for evaluating tonic pain in parrots, and measurement of the weight-bearing load was accurate for assessment of arthritic pain; however, behavioral changes associated with pain were subtle.

Thermally Stratified Compression Ignition: A new advanced low temperature combustion mode with load flexibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawler, Benjamin; Splitter, Derek; Szybist, James

We introduce a new advanced combustion mode, called Thermally Stratified Compression Ignition (TSCI), which uses direct water injection to control both the average temperature and the temperature distribution prior to ignition, thereby providing cycle-to-cycle control over the start and rate of heat release in Low Temperature Combustion (LTC). Experiments were conducted to fundamentally understand the effects of water injection on heat release in LTC. Our results show that water injection retards the start of combustion due to the latent heat of vaporization of the injected water. Furthermore, for start of water injection timings between 20 and 70 degrees before topmore » dead center, combustion is significantly elongated compared to without water injection. The 10–90% burn duration with 6.6 and 9.0 mg of water per cycle was 77% and 146% longer than without water injection, respectively. Forced thermal stratification result from a direct water injection which reduces the heat release rate by local evaporative cooling. Finally, the load limits with and without water injection were determined experimentally. Without water injection, the load range was 2.3–3.6 bar gross IMEP. By using water injection to control heat release, the load range in TSCI was 2.3–8.4 bar gross IMEP, which is a range expansion of over 350%. These results demonstrate that direct water injection can provide significant improvements to both controllability and the range of operability of LTC, thereby resolving the major challenges associated with HCCI.« less

Beech wood Fagus sylvatica dilute-acid hydrolysate as a feedstock to support Chlorella sorokiniana biomass, fatty acid and pigment production.

PubMed

Miazek, Krystian; Remacle, Claire; Richel, Aurore; Goffin, Dorothee

2017-04-01

This work evaluates the possibility of using beech wood (Fagus sylvatica) dilute-acid (H 2 SO 4 ) hydrolysate as a feedstock for Chlorella sorokiniana growth, fatty acid and pigment production. Neutralized wood acid hydrolysate, containing organic and mineral compounds, was tested on Chlorella growth at different concentrations and compared to growth under phototrophic conditions. Chlorella growth was improved at lower loadings and inhibited at higher loadings. Based on these results, a 12% neutralized wood acid hydrolysate (Hyd12%) loading was selected to investigate its impact on Chlorella growth, fatty acid and pigment production. Hyd12% improved microalgal biomass, fatty acid and pigment productivities both in light and in dark, when compared to photoautotrophic control. Light intensity had substantial influence on fatty acid and pigment composition in Chlorella culture during Hyd12%-based growth. Moreover, heterotrophic Chlorella cultivation with Hyd12% also showed that wood hydrolysate can constitute an attractive feedstock for microalgae cultivation in case of lack of light. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhanced Sucrose Loading Improves Rice Yield by Increasing Grain Size1[OPEN

PubMed Central

Wang, Liang; Lu, Qingtao

2015-01-01

Yield in cereals is a function of grain number and size. Sucrose (Suc), the main carbohydrate product of photosynthesis in higher plants, is transported long distances from source leaves to sink organs such as seeds and roots. Here, we report that transgenic rice plants (Oryza sativa) expressing the Arabidopsis (Arabidopsis thaliana) phloem-specific Suc transporter (AtSUC2), which loads Suc into the phloem under control of the phloem protein2 promoter (pPP2), showed an increase in grain yield of up to 16% relative to wild-type plants in field trials. Compared with wild-type plants, pPP2::AtSUC2 plants had larger spikelet hulls and larger and heavier grains. Grain filling was accelerated in the transgenic plants, and more photoassimilate was transported from the leaves to the grain. In addition, microarray analyses revealed that carbohydrate, amino acid, and lipid metabolism was enhanced in the leaves and grain of pPP2::AtSUC2 plants. Thus, enhancing Suc loading represents a promising strategy to improve rice yield to feed the global population. PMID:26504138

Enhanced Sucrose Loading Improves Rice Yield by Increasing Grain Size.

PubMed

Wang, Liang; Lu, Qingtao; Wen, Xiaogang; Lu, Congming

2015-12-01

Yield in cereals is a function of grain number and size. Sucrose (Suc), the main carbohydrate product of photosynthesis in higher plants, is transported long distances from source leaves to sink organs such as seeds and roots. Here, we report that transgenic rice plants (Oryza sativa) expressing the Arabidopsis (Arabidopsis thaliana) phloem-specific Suc transporter (AtSUC2), which loads Suc into the phloem under control of the phloem protein2 promoter (pPP2), showed an increase in grain yield of up to 16% relative to wild-type plants in field trials. Compared with wild-type plants, pPP2::AtSUC2 plants had larger spikelet hulls and larger and heavier grains. Grain filling was accelerated in the transgenic plants, and more photoassimilate was transported from the leaves to the grain. In addition, microarray analyses revealed that carbohydrate, amino acid, and lipid metabolism was enhanced in the leaves and grain of pPP2::AtSUC2 plants. Thus, enhancing Suc loading represents a promising strategy to improve rice yield to feed the global population. © 2015 American Society of Plant Biologists. All Rights Reserved.

Carbon nanotubes as VEGF carriers to improve the early vascularization of porcine small intestinal submucosa in abdominal wall defect repair

PubMed Central

Liu, Zhengni; Feng, Xueyi; Wang, Huichun; Ma, Jun; Liu, Wei; Cui, Daxiang; Gu, Yan; Tang, Rui

2014-01-01

Insufficient early vascularization in biological meshes, resulting in limited host tissue incorporation, is thought to be the primary cause for the failure of abdominal wall defect repair after implantation. The sustained release of exogenous angiogenic factors from a biocompatible nanomaterial might be a way to overcome this limitation. In the study reported here, multiwalled carbon nanotubes (MWNT) were functionalized by plasma polymerization to deliver vascular endothelial growth factor165 (VEGF165). The novel VEGF165-controlled released system was incorporated into porcine small intestinal submucosa (PSIS) to construct a composite scaffold. Scaffolds incorporating varying amounts of VEGF165-loaded functionalized MWNT were characterized in vitro. At 5 weight percent MWNT, the scaffolds exhibited optimal properties and were implanted in rats to repair abdominal wall defects. PSIS scaffolds incorporating VEGF165-loaded MWNT (VEGF–MWNT–PSIS) contributed to early vascularization from 2–12 weeks postimplantation and obtained more effective collagen deposition and exhibited improved tensile strength at 24 weeks postimplantation compared to PSIS or PSIS scaffolds, incorporating MWNT without VEGF165 loading (MWNT–PSIS). PMID:24648727

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winkler, Jon; Booten, Chuck

Residential building codes and voluntary labeling programs are continually increasing the energy efficiency requirements of residential buildings. Improving a building's thermal enclosure and installing energy-efficient appliances and lighting can result in significant reductions in sensible cooling loads leading to smaller air conditioners and shorter cooling seasons. However due to fresh air ventilation requirements and internal gains, latent cooling loads are not reduced by the same proportion. Thus, it's becoming more challenging for conventional cooling equipment to control indoor humidity at part-load cooling conditions and using conventional cooling equipment in a non-conventional building poses the potential risk of high indoor humidity.more » The objective of this project was to investigate the impact the chosen design condition has on the calculated part-load cooling moisture load, and compare calculated moisture loads and the required dehumidification capacity to whole-building simulations. Procedures for sizing whole-house supplemental dehumidification equipment have yet to be formalized; however minor modifications to current Air-Conditioner Contractors of America (ACCA) Manual J load calculation procedures are appropriate for calculating residential part-load cooling moisture loads. Though ASHRAE 1% DP design conditions are commonly used to determine the dehumidification requirements for commercial buildings, an appropriate DP design condition for residential buildings has not been investigated. Two methods for sizing supplemental dehumidification equipment were developed and tested. The first method closely followed Manual J cooling load calculations; whereas the second method made more conservative assumptions impacting both sensible and latent loads.« less

Jump Training in Youth Soccer Players: Effects of Haltere Type Handheld Loading.

PubMed

Rosas, F; Ramirez-Campillo, R; Diaz, D; Abad-Colil, F; Martinez-Salazar, C; Caniuqueo, A; Cañas-Jamet, R; Loturco, I; Nakamura, F Y; McKenzie, C; Gonzalez-Rivera, J; Sanchez-Sanchez, J; Izquierdo, M

2016-12-01

The aim of this study was to compare the effects of a jump training program, with or without haltere type handheld loading, on maximal intensity exercise performance. Youth soccer players (12.1±2.2 y) were assigned to either a jump training group (JG, n=21), a jump training group plus haltere type handheld loading (LJG, n=21), or a control group following only soccer training (CG, n=21). Athletes were evaluated for maximal-intensity performance measures before and after 6 weeks of training, during an in-season training period. The CG achieved a significant change in maximal kicking velocity only (ES=0.11-0.20). Both jump training groups improved in right leg (ES=0.28-0.45) and left leg horizontal countermovement jump with arms (ES=0.32-0.47), horizontal countermovement jump with arms (ES=0.28-0.37), vertical countermovement jump with arms (ES=0.26), 20-cm drop jump reactive strength index (ES=0.20-0.37), and maximal kicking velocity (ES=0.27-0.34). Nevertheless, compared to the CG, only the LJG exhibited greater improvements in all performance tests. Therefore, haltere type handheld loading further enhances performance adaptations during jump training in youth soccer players. © Georg Thieme Verlag KG Stuttgart · New York.

[Effect analysis on the two total load control methods for poisonous heavy metals].

PubMed

Fu, Guo-Wei

2012-12-01

Firstly it should be made clear that implementation of source total load control for the first type of pollutants is necessary for environmental pollution control legislation and economic structure regulation. This kind of surveillance method has been more practical to be implemented since the Manual of the Industry Discharge Coefficient of First National Pollution Sources Investigation was published. The source total load control and water environment total load control are independent of each other and none of them is redundant, on the other side they can be complementary to each other. In the present, some local planning managers are blurring and confusing the contents and styles of the two surveillance methods. They just use the water total load control to manage all the pollutants, and source total load control is discarded, which results in the loss of control for the first type of pollutants especially for the drinking water source surveillance. There is a big difference between the water quality standards and the water environmental background concentration values for the first type of pollutants in the Environmental quality standard for surface water (GB 3838-88), which means that there are problems such as "relaxing the pollutant discharge permit" and "risk induced by valence state change". Taking an enterprise with 10t electrolytic lead production capacity as an example, there is a big difference between the allowable lead discharged loads by the two total load surveillance methods. In summary, it will bring a lot of harmful effects if the water total load control is implemented for the two types of pollutants, so the source total load control and water environmental total load control should be implemented strictly at the same time.

Control of thumb force using surface functional electrical stimulation and muscle load sharing

PubMed Central

2013-01-01

Background Stroke survivors often have difficulties in manipulating objects with their affected hand. Thumb control plays an important role in object manipulation. Surface functional electrical stimulation (FES) can assist movement. We aim to control the 2D thumb force by predicting the sum of individual muscle forces, described by a sigmoidal muscle recruitment curve and a single force direction. Methods Five able bodied subjects and five stroke subjects were strapped in a custom built setup. The forces perpendicular to the thumb in response to FES applied to three thumb muscles were measured. We evaluated the feasibility of using recruitment curve based force vector maps in predicting output forces. In addition, we developed a closed loop force controller. Load sharing between the three muscles was used to solve the redundancy problem having three actuators to control forces in two dimensions. The thumb force was controlled towards target forces of 0.5 N and 1.0 N in multiple directions within the individual’s thumb work space. Hereby, the possibilities to use these force vector maps and the load sharing approach in feed forward and feedback force control were explored. Results The force vector prediction of the obtained model had small RMS errors with respect to the actual measured force vectors (0.22±0.17 N for the healthy subjects; 0.17±0.13 N for the stroke subjects). The stroke subjects showed a limited work range due to limited force production of the individual muscles. Performance of feed forward control without feedback, was better in healthy subjects than in stroke subjects. However, when feedback control was added performances were similar between the two groups. Feedback force control lead, especially for the stroke subjects, to a reduction in stationary errors, which improved performance. Conclusions Thumb muscle responses to FES can be described by a single force direction and a sigmoidal recruitment curve. Force in desired direction can be generated through load sharing among redundant muscles. The force vector maps are subject specific and also suitable in feedforward and feedback control taking the individual’s available workspace into account. With feedback, more accurate control of muscle force can be achieved. PMID:24103414

Intelligent control of a multi-degree-of freedom reaction compensating platform system using fuzzy logic

NASA Technical Reports Server (NTRS)

Choi, Benjamin B.; Lawrence, Charles; Lin, Yueh-Jaw

1994-01-01

This paper presents the development of a general-purpose fuzzy logic (FL) control methodology for isolating the external vibratory disturbances of space-based devices. According to the desired performance specifications, a full investigation regarding the development of an FL controller was done using different scenarios, such as variances of passive reaction-compensating components and external disturbance load. It was shown that the proposed FL controller is robust in that the FL-controlled system closely follows the prespecified ideal reference model. The comparative study also reveals that the FL-controlled system achieves significant improvement in reducing vibrations over passive systems.

Active self-healing encapsulation of vaccine antigens in PLGA microspheres

PubMed Central

Desai, Kashappa-Goud H.; Schwendeman, Steven P.

2013-01-01

Herein, we describe the detailed development of a simple and effective method to microencapsulate vaccine antigens in poly(lactic-co-glycolic acid) (PLGA) by simple mixing of preformed active self-microencapsulating (SM) PLGA microspheres in a low concentration aqueous antigen solution at modest temperature (10-38 °C). Co-encapsulating protein-sorbing vaccine adjuvants and polymer plasticizers were used to “actively” load the protein in the polymer pores and facilitate polymer self-healing at temperature > hydrated polymer glass transition temperature, respectively. The microsphere formulation parameters and loading conditions to provide optimal active self-healing microencapsulation of vaccine antigen in PLGA was investigated. Active self-healing encapsulation of two vaccine antigens, ovalbumin and tetanus toxoid (TT), in PLGA microspheres was adjusted by preparing blank microspheres containing different vaccine adjuvant (aluminum hydroxide (Al(OH)3) or calcium phosphate). Active loading of vaccine antigen in Al(OH)3-PLGA microspheres was found to: a) increase proportionally with an increasing loading of Al(OH)3 (0.88-3 wt%) and addition of porosigen, b) decrease when the inner Al(OH)3/trehalose phase to 1 mL outer oil phase and size of microspheres was respectively > 0.2 mL and 63 μm, and c) change negligibly by PLGA concentration and initial incubation (loading) temperature. Encapsulation of protein sorbing Al(OH)3 in PLGA microspheres resulted in suppression of self-healing of PLGA pores, which was then overcome by improving polymer chain mobility, which in turn was accomplished by coincorporating hydrophobic plasticizers in PLGA. Active self-healing microencapsulation of manufacturing process-labile TT in PLGA was found to: a) obviate micronization- and organic solvent-induced TT degradation, b) improve antigen loading (1.4-1.8 wt% TT) and encapsulation efficiency (~ 97%), c) provide nearly homogeneous distribution and stabilization of antigen in polymer, and d) provide improved in vitro controlled release of antigenic TT. PMID:23103983

Population-based analysis of Alzheimer's disease risk alleles implicates genetic interactions.

PubMed

Ebbert, Mark T W; Ridge, Perry G; Wilson, Andrew R; Sharp, Aaron R; Bailey, Matthew; Norton, Maria C; Tschanz, JoAnn T; Munger, Ronald G; Corcoran, Christopher D; Kauwe, John S K

2014-05-01

Reported odds ratios and population attributable fractions (PAF) for late-onset Alzheimer's disease (LOAD) risk loci (BIN1, ABCA7, CR1, MS4A4E, CD2AP, PICALM, MS4A6A, CD33, and CLU) come from clinically ascertained samples. Little is known about the combined PAF for these LOAD risk alleles and the utility of these combined markers for case-control prediction. Here we evaluate these loci in a large population-based sample to estimate PAF and explore the effects of additive and nonadditive interactions on LOAD status prediction performance. 2419 samples from the Cache County Memory Study were genotyped for APOE and nine LOAD risk loci from AlzGene.org. We used logistic regression and receiver operator characteristic analysis to assess the LOAD status prediction performance of these loci using additive and nonadditive models and compared odds ratios and PAFs between AlzGene.org and Cache County. Odds ratios were comparable between Cache County and AlzGene.org when identical single nucleotide polymorphisms were genotyped. PAFs from AlzGene.org ranged from 2.25% to 37%; those from Cache County ranged from .05% to 20%. Including non-APOE alleles significantly improved LOAD status prediction performance (area under the curve = .80) over APOE alone (area under the curve = .78) when not constrained to an additive relationship (p < .03). We identified potential allelic interactions (p values uncorrected): CD33-MS4A4E (synergy factor = 5.31; p < .003) and CLU-MS4A4E (synergy factor = 3.81; p < .016). Although nonadditive interactions between loci significantly improve diagnostic ability, the improvement does not reach the desired sensitivity or specificity for clinical use. Nevertheless, these results suggest that understanding gene-gene interactions may be important in resolving Alzheimer's disease etiology. Copyright © 2014 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Comprehensive joint feedback control for standing by functional neuromuscular stimulation-a simulation study.

PubMed

Nataraj, Raviraj; Audu, Musa L; Kirsch, Robert F; Triolo, Ronald J

2010-12-01

Previous investigations of feedback control of standing after spinal cord injury (SCI) using functional neuromuscular stimulation (FNS) have primarily targeted individual joints. This study assesses the potential efficacy of comprehensive (trunk, hips, knees, and ankles) joint feedback control against postural disturbances using a bipedal, 3-D computer model of SCI stance. Proportional-derivative feedback drove an artificial neural network trained to produce muscle excitation patterns consistent with maximal joint stiffness values achievable about neutral stance given typical SCI muscle properties. Feedback gains were optimized to minimize upper extremity (UE) loading required to stabilize against disturbances. Compared to the baseline case of maximum constant muscle excitations used clinically, the controller reduced UE loading by 55% in resisting external force perturbations and by 84% during simulated one-arm functional tasks. Performance was most sensitive to inaccurate measurements of ankle plantar/dorsiflexion position and hip ab/adduction velocity feedback. In conclusion, comprehensive joint feedback demonstrates potential to markedly improve FNS standing function. However, alternative control structures capable of effective performance with fewer sensor-based feedback parameters may better facilitate clinical usage.

Comprehensive Joint Feedback Control for Standing by Functional Neuromuscular Stimulation – a Simulation Study

PubMed Central

Nataraj, Raviraj; Audu, Musa L.; Kirsch, Robert F.; Triolo, Ronald J.

2013-01-01

Previous investigations of feedback control of standing after spinal cord injury (SCI) using functional neuromuscular stimulation (FNS) have primarily targeted individual joints. This study assesses the potential efficacy of comprehensive (trunk, hips, knees, and ankles) joint-feedback control against postural disturbances using a bipedal, three-dimensional computer model of SCI stance. Proportional-derivative feedback drove an artificial neural network trained to produce muscle excitation patterns consistent with maximal joint stiffness values achievable about neutral stance given typical SCI muscle properties. Feedback gains were optimized to minimize upper extremity (UE) loading required to stabilize against disturbances. Compared to the baseline case of maximum constant muscle excitations used clinically, the controller reduced UE loading by 55% in resisting external force perturbations and by 84% during simulated one-arm functional tasks. Performance was most sensitive to inaccurate measurements of ankle plantar/dorsiflexion position and hip ab/adduction velocity feedback. In conclusion, comprehensive joint-feedback demonstrates potential to markedly improve FNS standing function. However, alternative control structures capable of effective performance with fewer sensor-based feedback parameters may better facilitate clinical usage. PMID:20923741

14 CFR 27.681 - Limit load static tests.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Control Systems § 27.681 Limit load... which— (1) The direction of the test loads produces the most severe loading in the control system; and... requirements for control system joints subject to angular motion. ...

High-polyphenol chocolate reduces endothelial dysfunction and oxidative stress during acute transient hyperglycaemia in Type 2 diabetes: a pilot randomized controlled trial.

PubMed

Mellor, D D; Madden, L A; Smith, K A; Kilpatrick, E S; Atkin, S L

2013-04-01

To investigate the effects of high-polyphenol chocolate upon endothelial function and oxidative stress in Type 2 diabetes mellitus during acute transient hyperglycaemia induced following a 75-g oral glucose challenge. Ten subjects with Type 2 diabetes underwent a double-blinded randomized controlled crossover study. A 75-g oral glucose load was used to induce hyperglycaemia, which was administered to participants 60 min after they had ingested either low (control) or high-polyphenol chocolate. Participants undertook testing at weekly intervals, following an initial cocoa-free period. Endothelial function was assessed by both functional [reactive hyperaemia peripheral artery tonometry (EndoPAT-2000) and serum markers (including intercellular adhesion molecule 1, P-selectin and P-selectin glycoprotein ligand 1]. Urinary 15-F2t-isoprostane adjusted for creatinine was used as an oxidative stress marker. Measurements were made at baseline and 2 h post-ingestion of the glucose load. Prior consumption of high-polyphenol chocolate before a glucose load improved endothelial function (1.7 ± 0.1 vs. 2.3 ± 0.1%, P = 0.01), whereas prior consumption of control chocolate resulted in a significant increase in intercellular adhesion molecule 1 (321.1 ± 7.6 vs. 373.6 ± 10.5 ng/ml, P = 0.04) and 15-F2t-isoprostane (116.8 ± 5.7 vs. 207.1 ± 5.7 mg/mol, P = 0.02). Analysis of percentage changes from baseline comparing control and high-polyphenol chocolate showed a significant improvement for high-polyphenol chocolate in both measures of endothelial function (P < 0.05) and for urinary 15-F2t-isoprostane (P = 0.04). High-polyphenol chocolate protected against acute hyperglycaemia-induced endothelial dysfunction and oxidative stress in individuals with Type 2 diabetes mellitus. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

Combined wind turbine fatigue and ultimate load reduction by individual blade control

NASA Astrophysics Data System (ADS)

Han, Y.; Leithead, W. E.

2014-06-01

If each blade of the wind turbine has individual pitch actuator, there is possibility of employing the pitch system to mitigate structural loads through advanced control methods. Previously, considerable reduction of blade lifetime equivalent fatigue loads has been achieved by Individual Blade Control (IBC) and in addition, it has also been shown the potential in blade ultimate loads reduction. However, both fatigue and ultimate loads impact on the design and life of wind turbine blades. In this paper, the design and application of IBC that concurrently reduce both blade fatigue and ultimate loads is investigated. The contributions of blade load spectral components, which are 1P, 2P and edgewise mode from blade in-plane and/or out-of-plane bending moments, are firstly explored. Four different control options for reducing various combinations of these load components are compared. In response to the different spectral peaks of both fatigue and ultimate loads, the controller has been designed so that it can act on different frequency components which vary with wind speed. The performance of the IBC controller on fatigue and ultimate load reduction is assessed by simulating a 5MW exemplar wind turbine. Simulation results show that with a proper selection of controlling inputs at different wind speed, the use of a single combined IBC can achieve satisfactory reduction on both fatigue and ultimate loads.

Reactivity-controlled compression ignition drive cycle emissions and fuel economy estimations using vehicle system simulations

DOE PAGES

Curran, Scott J.; Gao, Zhiming; Wagner, Robert M.

2014-12-22

In-cylinder blending of gasoline and diesel to achieve reactivity-controlled compression ignition has been shown to reduce NO X and soot emissions while maintaining or improving brake thermal efficiency as compared with conventional diesel combustion. The reactivity-controlled compression ignition concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load, allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. In this paper, a multi-mode reactivity-controlled compression ignition strategy is employed where the engine switches from reactivity-controlled compression ignition to conventional diesel combustionmore » when speed and load demand are outside of the experimentally determined reactivity-controlled compression ignition range. The potential for reactivity-controlled compression ignition to reduce drive cycle fuel economy and emissions is not clearly understood and is explored here by simulating the fuel economy and emissions for a multi-mode reactivity-controlled compression ignition–enabled vehicle operating over a variety of US drive cycles using experimental engine maps for multi-mode reactivity-controlled compression ignition, conventional diesel combustion, and a 2009 port-fuel injected gasoline engine. Drive cycle simulations are completed assuming a conventional mid-size passenger vehicle with an automatic transmission. Multi-mode reactivity-controlled compression ignition fuel economy simulation results are compared with the same vehicle powered by a representative 2009 port-fuel injected gasoline engine over multiple drive cycles. Finally, engine-out drive cycle emissions are compared with conventional diesel combustion, and observations regarding relative gasoline and diesel tank sizes needed for the various drive cycles are also summarized.« less

Improvement of mechanical and biological properties of Polycaprolactone loaded with Hydroxyapatite and Halloysite nanotubes.

PubMed

Torres, E; Fombuena, V; Vallés-Lluch, A; Ellingham, T

2017-06-01

Hydroxyapatite (HA) and Halloysite nanotubes (HNTs) percentages have been optimized in Polycaprolactone (PCL) polymeric matrices to improve mechanical, thermal and biological properties of the composites, thus, to be applied in bone tissue engineering or as fixation plates. Addition of HA guarantees a proper compatibility with human bone due to its osteoconductive and osteoinductive properties, facilitating bone regeneration in tissue engineering applications. Addition of HNTs ensures the presence of tubular structures for subsequent drug loading in their lumen, of molecules such as curcumin, acting as controlled drug delivery systems. The addition of 20% of HA and different amounts of HNTs leads to a substantial improvement in mechanical properties with values of flexural strength up to 40% over raw PCL, with an increase in degradation temperature. DMA analyses showed stability in mechanical and thermal properties, having as a result a potential composite to be used as tissue engineering scaffold or resorbable fixation plate. Copyright © 2017 Elsevier B.V. All rights reserved.

Compliance and stress sensitivity of spur gear teeth

NASA Technical Reports Server (NTRS)

Cornell, R. W.

1983-01-01

The magnitude and variation of tooth pair compliance with load position affects the dynamics and loading significantly, and the tooth root stressing per load varies significantly with load position. Therefore, the recently developed time history, interactive, closed form solution for the dynamic tooth loads for both low and high contact ratio spur gears was expanded to include improved and simplified methods for calculating the compliance and stress sensitivity for three involute tooth forms as a function of load position. The compliance analysis has an improved fillet/foundation. The stress sensitivity analysis is a modified version of the Heywood method but with an improvement in the magnitude and location of the peak stress in the fillet. These improved compliance and stress sensitivity analyses are presented along with their evaluation using test, finite element, and analytic transformation results, which showed good agreement.

Tweaking Dendrimers and Dendritic Nanoparticles for Controlled Nano-bio Interactions: Potential Nanocarriers for Improved Cancer Targeting

PubMed Central

Bugno, Jason; Hsu, Hao-Jui; Hong, Seungpyo

2016-01-01

Nanoparticles have shown great promise in the treatment of cancer, with a demonstrated potential in targeted drug delivery. Among a myriad of nanocarriers that have been recently developed, dendrimers have attracted a great deal of scientific interests due to their unique chemical and structural properties that allow for precise engineering of their characteristics. Despite this, the clinical translation of dendrimers has been hindered due to their drawbacks, such as scale-up issues, rapid systemic elimination, inefficient tumor accumulation, and limited drug loading. In order to overcome these limitations, a series of reengineered dendrimers have been recently introduced using various approaches, including: i) modifications of structure and surfaces; ii) integration with linear polymers; and iii) hybridization with other types of nanocarriers. Chemical modifications and surface engineering have tailored dendrimers to improve their pharmacokinetics and tissue permeation. Copolymerization of dendritic polymers with linear polymers has resulted in various amphiphilic copolymers with self-assembly capabilities and improved drug loading efficiencies. Hybridization with other nanocarriers integrates advantageous characteristics of both systems, which includes prolonged plasma circulation times and enhanced tumor targeting. This review provides a comprehensive summary of the newly emerging drug delivery systems that involve reengineering of dendrimers in an effort to precisely control their nano-bio interactions, mitigating their inherent weaknesses. PMID:26453160

An Overview of Modifications Applied to a Turbulence Response Analysis Method for Flexible Aircraft Configurations

NASA Technical Reports Server (NTRS)

Funk, Christie J.

2013-01-01

A software program and associated methodology to study gust loading on aircraft exists for a classification of geometrically simplified flexible configurations. This program consists of a simple aircraft response model with two rigid and three flexible symmetric degrees of freedom and allows for the calculation of various airplane responses due to a discrete one-minus-cosine gust as well as continuous turbulence. Simplifications, assumptions, and opportunities for potential improvements pertaining to the existing software program are first identified, then a revised version of the original software tool is developed with improved methodology to include more complex geometries, additional excitation cases, and output data so as to provide a more useful and accurate tool for gust load analysis. Revisions are made in the categories of aircraft geometry, computation of aerodynamic forces and moments, and implementation of horizontal tail mode shapes. In order to improve the original software program to enhance usefulness, a wing control surface and horizontal tail control surface is added, an extended application of the discrete one-minus-cosine gust input is employed, a supplemental continuous turbulence spectrum is implemented, and a capability to animate the total vehicle deformation response to gust inputs in included. These revisions and enhancements are implemented and an analysis of the results is used to validate the modifications.

Simultaneously Load and Extended Release of Betamethasone and Ciprofloxacin from Vitamin E-Loaded Silicone-Based Soft Contact Lenses.

PubMed

Rad, Maryam Shayani; Mohajeri, Seyed Ahmad

2016-09-01

The purpose of the present study was to evaluate the efficacy of commercial soft contact lenses, loaded with vitamin E, as ocular drug delivery systems for simultaneous loading and release of ciprofloxacin (Cipro) and betamethasone (BMZ) in artificial tears. In this study, we applied vitamin E as a barrier to increase BMZ-Cipro loading into three commercial silicone-based soft contact lenses and control their simultaneous release into the artificial lachrymal fluid. Two different concentrations of vitamin E solution (0.1 and 0.2 g/ml) were used, and various parameters including changes in lens diameter, water content, ultraviolet-visible light (UV-Vis) transmittance, drug-binding properties, and drug release profile were investigated. The obtained results indicated that vitamin E significantly reduced the swelling properties of contact lenses in aqueous media, while it enhanced the lens diameter in both dry and hydrated states. Vitamin E had no significant effects on visible transmittance, while it blocked UV radiation, which could be harmful for the eye surface. Our findings revealed that vitamin E improved the simultaneous loading amount of BMZ-Cipro into soft contact lenses. Additionally, BMZ and Cipro release rates significantly reduced after using vitamin E as a hydrophobic diffusion barrier. After soaking the lenses in 0.1 and 0.2 g/ml of vitamin E solution, BMZ release time increased by 28.8-81.6 and 182.4-201 folds, respectively. Moreover, Cipro release time increased by 12-18 and 1152-2313 folds, respectively. The results of the present study indicated the efficacy of vitamin E as a diffusion barrier in developing a controlled drug delivery system for the simultaneous loading of BMZ and Cipro and sustaining their release from soft contact lenses.

Low Probability Tail Event Analysis and Mitigation in BPA Control Area: Task One Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Shuai; Makarov, Yuri V.

This is a report for task one of the tail event analysis project for BPA. Tail event refers to the situation in a power system when unfavorable forecast errors of load and wind are superposed onto fast load and wind ramps, or non-wind generators falling short of scheduled output, the imbalance between generation and load becomes very significant. This type of events occurs infrequently and appears on the tails of the distribution of system power imbalance; therefore, is referred to as tail events. This report analyzes what happened during the Electric Reliability Council of Texas (ERCOT) reliability event on Februarymore » 26, 2008, which was widely reported because of the involvement of wind generation. The objective is to identify sources of the problem, solutions to it and potential improvements that can be made to the system. Lessons learned from the analysis include the following: (1) Large mismatch between generation and load can be caused by load forecast error, wind forecast error and generation scheduling control error on traditional generators, or a combination of all of the above; (2) The capability of system balancing resources should be evaluated both in capacity (MW) and in ramp rate (MW/min), and be procured accordingly to meet both requirements. The resources need to be able to cover a range corresponding to the variability of load and wind in the system, additional to other uncertainties; (3) Unexpected ramps caused by load and wind can both become the cause leading to serious issues; (4) A look-ahead tool evaluating system balancing requirement during real-time operations and comparing that with available system resources should be very helpful to system operators in predicting the forthcoming of similar events and planning ahead; and (5) Demand response (only load reduction in ERCOT event) can effectively reduce load-generation mismatch and terminate frequency deviation in an emergency situation.« less

Active load control during rolling maneuvers. [performed in the Langley Transonic Dynamics Tunnel

NASA Technical Reports Server (NTRS)

Woods-Vedeler, Jessica A.; Pototzky, Anthony S.; Hoadley, Sherwood T.

1994-01-01

A rolling maneuver load alleviation (RMLA) system has been demonstrated on the active flexible wing (AFW) wind tunnel model in the Langley Transonic Dynamics Tunnel (TDT). The objective was to develop a systematic approach for designing active control laws to alleviate wing loads during rolling maneuvers. Two RMLA control laws were developed that utilized outboard control-surface pairs (leading and trailing edge) to counteract the loads and that used inboard trailing-edge control-surface pairs to maintain roll performance. Rolling maneuver load tests were performed in the TDT at several dynamic pressures that included two below and one 11 percent above open-loop flutter dynamic pressure. The RMLA system was operated simultaneously with an active flutter suppression system above open-loop flutter dynamic pressure. At all dynamic pressures for which baseline results were obtained, torsion-moment loads were reduced for both RMLA control laws. Results for bending-moment load reductions were mixed; however, design equations developed in this study provided conservative estimates of load reduction in all cases.

Design and Development of a Residential Gas-Fired Heat Pump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vineyard, Edward Allan; Abu-Heiba, Ahmad; Mahderekal, Dr. Isaac

2017-01-01

Heating, ventilating, and air-conditioning equipment consumes 43% of the total primary energy consumption in U.S. households. Presently, conventional gas furnaces have maximum heating efficiencies of 98%. Electric air conditioners used in association with the furnace for cooling have a minimum seasonal energy efficiency ratio (SEER) of 14.0. A residential gas-fired heat pump (RGHP) was developed and tested under standard rating conditions, resulting in a significant increase in heating efficiency of over 40% versus conventional natural gas furnaces. The associated efficiency of the RGHP in cooling mode is comparable in efficiency to an electric air conditioner (14.0 SEER) when compared onmore » a primary energy basis. The RGHP is similar in nature to a conventional heat pump but with two main differences. First, the primary energy savings are higher, based on a site versus source comparison, as the result of using natural gas to supply shaft power to the compressor rather than an electric motor. Second, waste heat is recovered from the engine to supplement space heating and reduce the energy input. It can also be used to provide supplemental water heating. The system utilizes a programmable logic controller that allows variable-speed operation to achieve improved control to meet building loads. RGHPs significantly reduce peak electric use during periods of high demand, especially peak summer loads, as well as peak winter loads in regions with widespread use of electric heating. This contributes to leveling year-round gas loads, with the potential to increase annual gas demand in some regions. The widespread adoption of RGHPs will contribute to significant reductions in primary energy consumption and carbon emissions through improved efficiencies.« less

Robonaut 2 (R2) Overview

NASA Technical Reports Server (NTRS)

Diftler, Myron

2010-01-01

This slide presentation reviews the development and uses of the second robot designed to work in space. The presentation reviews the motivation for developing Robonaut, the cooperative commercial relationship with General Motors, the evolution design of Robonaut Robonaut 2 improvements over the first robonaut (R1), Robonaut 2's hand dexterity, finger impedance control, tactile system, finger haptics, arm control, strength, neck movement and head sensors, human interaction, and the controller. Also the plans for use on board the International Space Station are reviewed. The patent for the Phalange Tactile Load Cell is included.

Evaluation of a high response electrohydraulic digital control valve

NASA Technical Reports Server (NTRS)

Anderson, R. L.

1973-01-01

The application is described of a digital control valve on an electrohydraulic servo actuator. The digital control problem is discussed in general as well as the design and evaluation of a breadboard actuator. The evaluation revealed a number of problems associated with matching the valve to a hydraulic load. The problems were related to lost motion resulting from bulk modulus and leakage. These problems were effectively minimized in the breadboard actuator by maintaining a 1000 psi back pressure on the valve circuit and thereby improving the effective bulk modulus.

Manufacturing engineering: Principles for optimization

NASA Astrophysics Data System (ADS)

Koenig, Daniel T.

Various subjects in the area of manufacturing engineering are addressed. The topics considered include: manufacturing engineering organization concepts and management techniques, factory capacity and loading techniques, capital equipment programs, machine tool and equipment selection and implementation, producibility engineering, methods, planning and work management, and process control engineering in job shops. Also discussed are: maintenance engineering, numerical control of machine tools, fundamentals of computer-aided design/computer-aided manufacture, computer-aided process planning and data collection, group technology basis for plant layout, environmental control and safety, and the Integrated Productivity Improvement Program.

Advanced Intelligent System Application to Load Forecasting and Control for Hybrid Electric Bus

NASA Technical Reports Server (NTRS)

Momoh, James; Chattopadhyay, Deb; Elfayoumy, Mahmoud

1996-01-01

The primary motivation for this research emanates from providing a decision support system to the electric bus operators in the municipal and urban localities which will guide the operators to maintain an optimal compromise among the noise level, pollution level, fuel usage etc. This study is backed up by our previous studies on study of battery characteristics, permanent magnet DC motor studies and electric traction motor size studies completed in the first year. The operator of the Hybrid Electric Car must determine optimal power management schedule to meet a given load demand for different weather and road conditions. The decision support system for the bus operator comprises three sub-tasks viz. forecast of the electrical load for the route to be traversed divided into specified time periods (few minutes); deriving an optimal 'plan' or 'preschedule' based on the load forecast for the entire time-horizon (i.e., for all time periods) ahead of time; and finally employing corrective control action to monitor and modify the optimal plan in real-time. A fully connected artificial neural network (ANN) model is developed for forecasting the kW requirement for hybrid electric bus based on inputs like climatic conditions, passenger load, road inclination, etc. The ANN model is trained using back-propagation algorithm employing improved optimization techniques like projected Lagrangian technique. The pre-scheduler is based on a Goal-Programming (GP) optimization model with noise, pollution and fuel usage as the three objectives. GP has the capability of analyzing the trade-off among the conflicting objectives and arriving at the optimal activity levels, e.g., throttle settings. The corrective control action or the third sub-task is formulated as an optimal control model with inputs from the real-time data base as well as the GP model to minimize the error (or deviation) from the optimal plan. These three activities linked with the ANN forecaster proving the output to the GP model which in turn produces the pre-schedule of the optimal control model. Some preliminary results based on a hypothetical test case will be presented for the load forecasting module. The computer codes for the three modules will be made available fe adoption by bus operating agencies. Sample results will be provided using these models. The software will be a useful tool for supporting the control systems for the Electric Bus project of NASA.

Human factors aspects of control room design

NASA Technical Reports Server (NTRS)

Jenkins, J. P.

1983-01-01

A plan for the design and analysis of a multistation control room is reviewed. It is found that acceptance of the computer based information system by the uses in the control room is mandatory for mission and system success. Criteria to improve computer/user interface include: match of system input/output with user; reliability, compatibility and maintainability; easy to learn and little training needed; self descriptive system; system under user control; transparent language, format and organization; corresponds to user expectations; adaptable to user experience level; fault tolerant; dialog capability user communications needs reflected in flexibility, complexity, power and information load; integrated system; and documentation.

Photovoltaic power converter system with a controller configured to actively compensate load harmonics

DOEpatents

de Rooij, Michael Andrew; Steigerwald, Robert Louis; Delgado, Eladio Clemente

2008-12-16

Photovoltaic power converter system including a controller configured to reduce load harmonics is provided. The system comprises a photovoltaic array and an inverter electrically coupled to the array to generate an output current for energizing a load connected to the inverter and to a mains grid supply voltage. The system further comprises a controller including a first circuit coupled to receive a load current to measure a harmonic current in the load current. The controller includes a second circuit to generate a fundamental reference drawn by the load. The controller further includes a third circuit for combining the measured harmonic current and the fundamental reference to generate a command output signal for generating the output current for energizing the load connected to the inverter. The photovoltaic system may be configured to compensate harmonic currents that may be drawn by the load.

[Development and effectiveness of a drug dosage calculation training program using cognitive loading theory based on smartphone application].

PubMed

Kim, Myoung Soo; Park, Jung Ha; Park, Kyung Yeon

2012-10-01

This study was done to develop and evaluate a drug dosage calculation training program using cognitive loading theory based on a smartphone application. Calculation ability, dosage calculation related self-efficacy and anxiety were measured. A nonequivalent control group design was used. Smartphone application and a handout for self-study were developed and administered to the experimental group and only a handout was provided for control group. Intervention period was 4 weeks. Data were analyzed using descriptive analysis, χ²-test, t-test, and ANCOVA with the SPSS 18.0. The experimental group showed more 'self-efficacy for drug dosage calculation' than the control group (t=3.82, p<.001). Experimental group students had higher ability to perform drug dosage calculations than control group students (t=3.98, p<.001), with regard to 'metric conversion' (t=2.25, p=.027), 'table dosage calculation' (t=2.20, p=.031) and 'drop rate calculation' (t=4.60, p<.001). There was no difference in improvement in 'anxiety for drug dosage calculation'. Mean satisfaction score for the program was 86.1. These results indicate that this drug dosage calculation training program using smartphone application is effective in improving dosage calculation related self-efficacy and calculation ability. Further study should be done to develop additional interventions for reducing anxiety.

40 CFR 63.421 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Administrator and any other person. Controlled loading rack, for the purposes of § 63.420, means a loading rack... heat air pollutants to combustion temperatures. Uncontrolled loading rack means a loading rack used to load gasoline cargo tanks that is not a controlled loading rack. Vapor-tight gasoline cargo tank means...

Tailoring the Employment of Offshore Wind Turbine Support Structure Load Mitigation Controllers

NASA Astrophysics Data System (ADS)

Shrestha, Binita; Kühn, Martin

2016-09-01

The currently available control concepts to mitigate aerodynamic and hydrodynamic induced support structure loads reduce either fore-aft or side-to-side damage under certain operational conditions. The load reduction is achieved together with an increase in loads in other components of the turbine e.g. pitch actuators or drive train, increasing the risk of unscheduled maintenance. The main objective of this paper is to demonstrate a methodology for reduction of support structure damage equivalent loads (DEL) in fore-aft and side-to-side directions using already available control concepts. A multi-objective optimization problem is formulated to minimize the DELs, while limiting the collateral effects of the control algorithms for load reduction. The optimization gives trigger values of sea state condition for the activation or deactivation of certain control concepts. As a result, by accepting the consumption of a small fraction of the load reserve in the design load envelope of other turbine components, a considerable reduction of the support structure loads is facilitated.

Fatigue data for polyether ether ketone (PEEK) under fully-reversed cyclic loading

PubMed Central

Shrestha, Rakish; Simsiriwong, Jutima; Shamsaei, Nima

2016-01-01

In this article, the data obtained from the uniaxial fully-reversed fatigue experiments conducted on polyether ether ketone (PEEK), a semi-crystalline thermoplastic, are presented. The tests were performed in either strain-controlled or load-controlled mode under various levels of loading. The data are categorized into four subsets according to the type of tests, including (1) strain-controlled fatigue tests with adjusted frequency to obtain the nominal temperature rise of the specimen surface, (2) strain-controlled fatigue tests with various frequencies, (3) load-controlled fatigue tests without step loadings, and (4) load-controlled fatigue tests with step loadings. Accompanied data for each test include the fatigue life, the maximum (peak) and minimum (valley) stress–strain responses for each cycle, and the hysteresis stress–strain responses for each collected cycle in a logarithmic increment. A brief description of the experimental method is also given. PMID:26937465

Fatigue data for polyether ether ketone (PEEK) under fully-reversed cyclic loading.

PubMed

Shrestha, Rakish; Simsiriwong, Jutima; Shamsaei, Nima

2016-03-01

In this article, the data obtained from the uniaxial fully-reversed fatigue experiments conducted on polyether ether ketone (PEEK), a semi-crystalline thermoplastic, are presented. The tests were performed in either strain-controlled or load-controlled mode under various levels of loading. The data are categorized into four subsets according to the type of tests, including (1) strain-controlled fatigue tests with adjusted frequency to obtain the nominal temperature rise of the specimen surface, (2) strain-controlled fatigue tests with various frequencies, (3) load-controlled fatigue tests without step loadings, and (4) load-controlled fatigue tests with step loadings. Accompanied data for each test include the fatigue life, the maximum (peak) and minimum (valley) stress-strain responses for each cycle, and the hysteresis stress-strain responses for each collected cycle in a logarithmic increment. A brief description of the experimental method is also given.

Modular container assembled from fiber reinforced thermoplastic sandwich panels

DOEpatents

Donnelly, Mathew William; Kasoff, William Andrew; Mcculloch, Patrick Carl; Williams, Frederick Truman

2007-12-25

An improved, load bearing, modular design container structure assembled from thermoformed FRTP sandwich panels in which is utilized the unique core-skin edge configuration of the present invention in consideration of improved load bearing performance, improved useful load volume, reduced manufacturing costs, structural weight savings, impact and damage tolerance and repair and replace issues.

Real-Time Adaptive Control of a Magnetic Levitation System with a Large Range of Load Disturbance.

PubMed

Zhang, Zhizhou; Li, Xiaolong

2018-05-11

In an idle light-load or a full-load condition, the change of the load mass of a suspension system is very significant. If the control parameters of conventional control methods remain unchanged, the suspension performance of the control system deteriorates rapidly or even loses stability when the load mass changes in a large range. In this paper, a real-time adaptive control method for a magnetic levitation system with large range of mass changes is proposed. First, the suspension control system model of the maglev train is built up, and the stability of the closed-loop system is analyzed. Then, a fast inner current-loop is used to simplify the design of the suspension control system, and an adaptive control method is put forward to ensure that the system is still in a stable state when the load mass varies in a wide range. Simulations and experiments show that when the load mass of the maglev system varies greatly, the adaptive control method is effective to suspend the system stably with a given displacement.

Real-Time Adaptive Control of a Magnetic Levitation System with a Large Range of Load Disturbance

PubMed Central

Zhang, Zhizhou; Li, Xiaolong

2018-01-01

In an idle light-load or a full-load condition, the change of the load mass of a suspension system is very significant. If the control parameters of conventional control methods remain unchanged, the suspension performance of the control system deteriorates rapidly or even loses stability when the load mass changes in a large range. In this paper, a real-time adaptive control method for a magnetic levitation system with large range of mass changes is proposed. First, the suspension control system model of the maglev train is built up, and the stability of the closed-loop system is analyzed. Then, a fast inner current-loop is used to simplify the design of the suspension control system, and an adaptive control method is put forward to ensure that the system is still in a stable state when the load mass varies in a wide range. Simulations and experiments show that when the load mass of the maglev system varies greatly, the adaptive control method is effective to suspend the system stably with a given displacement. PMID:29751610

A free-piston Stirling engine/linear alternator controls and load interaction test facility

NASA Technical Reports Server (NTRS)

Rauch, Jeffrey S.; Kankam, M. David; Santiago, Walter; Madi, Frank J.

1992-01-01

A test facility at LeRC was assembled for evaluating free-piston Stirling engine/linear alternator control options, and interaction with various electrical loads. This facility is based on a 'SPIKE' engine/alternator. The engine/alternator, a multi-purpose load system, a digital computer based load and facility control, and a data acquisition system with both steady-periodic and transient capability are described. Preliminary steady-periodic results are included for several operating modes of a digital AC parasitic load control. Preliminary results on the transient response to switching a resistive AC user load are discussed.

Effect of healing time on bone-implant contact of orthodontic micro-implants: a histologic study.

PubMed

Ramazanzadeh, Barat Ali; Fatemi, Kazem; Dehghani, Mahboobe; Mohtasham, Nooshin; Jahanbin, Arezoo; Sadeghian, Hamed

2014-01-01

Objectives. This study aimed to evaluate the effect of immediate and delayed loading of orthodontic micro-implants on bone-implant contact. Materials and Methods. Sixty four micro-implants were implanted in dog's jaw bone. The micro-implants were divided into loaded and unloaded (control) groups. The control group had two subgroups: four and eight weeks being implanted. The loaded group had two subgroups of immediate loading and delayed (after four weeks healing) loading. Loaded samples were subjected to 200g load for four weeks. After sacrificing the animals micro-implants and surrounding tissues were observed histologically. Bone-implant contact ratios (BIC) were calculated and different groups' results were compared by three-way ANOVA. Results. Mean survival rate was 96.7% in general. Survival rates were 96.7%, 94.4% and 100% for control, immediate and delayed loaded groups, respectively. BIC values were not significantly different in loaded and control groups, immediate and delayed loading groups, and pressure and tension sides. Mandibular micro-implants had significantly higher BIC than maxillary ones in immediate loading, 4-weeks control, and 8-weeks control groups (P = 0.021, P = 0.009, P = 0.003, resp.). Conclusion Immediate or delayed loading of micro-implants in dog did not cause significant difference in Bone-implant contact which could be concluded that healing time had not significant effect on micro-implant stability.

Effect of Healing Time on Bone-Implant Contact of Orthodontic Micro-Implants: A Histologic Study

PubMed Central

Ramazanzadeh, Barat Ali; Fatemi, Kazem; Dehghani, Mahboobe; Mohtasham, Nooshin; Jahanbin, Arezoo; Sadeghian, Hamed

2014-01-01

Objectives. This study aimed to evaluate the effect of immediate and delayed loading of orthodontic micro-implants on bone-implant contact. Materials and Methods. Sixty four micro-implants were implanted in dog's jaw bone. The micro-implants were divided into loaded and unloaded (control) groups. The control group had two subgroups: four and eight weeks being implanted. The loaded group had two subgroups of immediate loading and delayed (after four weeks healing) loading. Loaded samples were subjected to 200g load for four weeks. After sacrificing the animals micro-implants and surrounding tissues were observed histologically. Bone-implant contact ratios (BIC) were calculated and different groups' results were compared by three-way ANOVA. Results. Mean survival rate was 96.7% in general. Survival rates were 96.7%, 94.4% and 100% for control, immediate and delayed loaded groups, respectively. BIC values were not significantly different in loaded and control groups, immediate and delayed loading groups, and pressure and tension sides. Mandibular micro-implants had significantly higher BIC than maxillary ones in immediate loading, 4-weeks control, and 8-weeks control groups (P = 0.021, P = 0.009, P = 0.003, resp.). Conclusion Immediate or delayed loading of micro-implants in dog did not cause significant difference in Bone-implant contact which could be concluded that healing time had not significant effect on micro-implant stability. PMID:25006463

Feline sporotrichosis: histopathological profile of cutaneous lesions and their correlation with clinical presentation.

PubMed

Miranda, Luisa H M; Conceição-Silva, Fátima; Quintella, Leonardo P; Kuraiem, Bianca P; Pereira, Sandro A; Schubach, Tânia M P

2013-07-01

Cutaneous lesions of feline sporotrichosis show high fungal load and are associated with severe disease and elevated zoonotic potential. The present study describes the histopathology and fungal load of the lesions in different clinical presentations of feline sporotrichosis. Cats with sporotrichosis were separated into groups L1, L2 and L3 (lesions in one, two and three or more locations, respectively) and subjected to skin biopsies for histopathology. Eighty-six cats were included in the study. Lesions were suppurative granulomatous in 84 cases and poorly formed granulomas were predominant. The well-formed granulomas were associated with group L1. The high fungal load was predominant in group L3 and in poorly formed granuloma cases and did not occur in well-formed granulomas cases. The good general condition was associated with low fungal load. These findings suggest that the fungal load control in animals with more localized lesions and well-organized response is linked with the improvement in the outcome of infected cats. Copyright © 2013 Elsevier Ltd. All rights reserved.

RETRACTED: Acarbose on insulin resistance after an oral fat load: a double-blind, placebo controlled study.

PubMed

Derosa, Giuseppe; Maffioli, Pamela; D'Angelo, Angela; Fogari, Elena; Bianchi, Lucio; Cicero, Arrigo F G

2011-01-01

We evaluated the effects of acarbose on insulin resistance parameters in diabetic patients before and after a standardized oral fat load (OFL). Patients were assigned to take acarbose 50 mg three times a day or placebo; after the first month, acarbose was titrated to 100 mg three times a day. We evaluated body mass index, glycemic control, fasting plasma insulin (FPI), post-prandial plasma insulin (PPI), homeostasis model assessment insulin resistance index (HOMA-IR), blood pressure, lipid profile, retinol binding protein-4 (RBP-4), adiponectin (ADN), tumor necrosis factor-α and resistin (r). Furthermore, at the baseline and at the end of the study, all patients underwent an OFL and an euglycemic hyperinsulinemic clamp. We observed that acarbose was better than placebo in improving glycemic control and HOMA-IR and that it was also more effective in improving lipid profile, RBP-4 and ADN. Regarding FPI, PPI and r, we did not obtain any significant differences between the two groups. During the second OFL, performed after 7 months of therapy with acarbose, we observed a significant decrease of blood glucose, lipid profile and all insulin resistance parameters peaks compared with the OFL administered at baseline with acarbose, but not with placebo. Acarbose was more effective than placebo in improving glycemic and lipid profile and in reducing the post-OFL peaks of the various parameters including the insulin resistance biomarkers. Copyright © 2011 Elsevier Inc. All rights reserved.

Cardiac data increase association between self-report and both expert ratings of task load and task performance in flight simulator tasks: An exploratory study.

PubMed

Lehrer, Paul; Karavidas, Maria; Lu, Shou-En; Vaschillo, Evgeny; Vaschillo, Bronya; Cheng, Andrew

2010-05-01

Seven professional airplane pilots participated in a one-session test in a Boeing 737-800 simulator. Mental workload for 18 flight tasks was rated by experienced test pilots (hereinafter called "expert ratings") and by study participants' self-report on NASA's Task Load Index (TLX) scale. Pilot performance was rated by a check pilot. The standard deviation of R-R intervals (SDNN) significantly added 3.7% improvement over the TLX in distinguishing high from moderate-load tasks and 2.3% improvement in distinguishing high from combined moderate and low-load tasks. Minimum RRI in the task significantly discriminated high- from medium- and low-load tasks, but did not add significant predictive variance to the TLX. The low-frequency/high-frequency (LF:HF) RRI ratio based on spectral analysis of R-R intervals, and ventricular relaxation time were each negatively related to pilot performance ratings independently of TLX values, while minimum and average RRI were positively related, showing added contribution of these cardiac measures for predicting performance. Cardiac results were not affected by controlling either for respiration rate or motor activity assessed by accelerometry. The results suggest that cardiac assessment can be a useful addition to self-report measures for determining flight task mental workload and risk for performance decrements. Replication on a larger sample is needed to confirm and extend the results. Copyright 2010 Elsevier B.V. All rights reserved.

In vitro characterization of pH-sensitive azithromycin-loaded methoxy poly (ethylene glycol)-block-poly (aspartic acid-graft-imidazole) micelles.

PubMed

Teng, Fangfang; Deng, Peizong; Song, Zhimei; Zhou, Feilong; Feng, Runliang; Liu, Na

2017-06-15

In order to improve azithromycin's antibacterial activity in acidic medium, monomethoxy poly (ethylene glycol)-block-poly (aspartic acid-graft-imidazole) copolymer was synthesized through allylation, free radical addition, ring-opening polymerization and amidation reactions with methoxy poly (ethylene glycol) as raw material. Drug loading capacity and encapsulation efficiency of azithromycin-loaded micelles prepared via thin film hydration method were 11.58±0.86% and 96.06±1.93%, respectively. The drug-loaded micelles showed pH-dependent property in the respects of particle size, zeta potential at the range of pH 5.5-7.8. It could control drug in vitro release and demonstrate higher release rate at pH 6.0 than that at pH 7.4. In vitro antibacterial experiment indicated that the activity of azithromycin-loaded micelles against S. aureus was superior to free azithromycin in medium at both pH 6.0 and pH 7.4. Using fluorescein as substitute with pH-dependent fluorescence decrease property, laser confocal fluorescence microscopy analysis confirmed that cellular uptake of micelles was improved due to protonation of copolymer's imidazole groups at pH 6.0. The enhanced cellular uptake and release of drug caused its activity enhancement in acidic medium when compared with free drug. The micellar drug delivery system should be potential application in the field of bacterial infection treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Experimental study on behavior of steel channel strengthened with CFRP

NASA Astrophysics Data System (ADS)

Tang, Hongyuan; Deng, Xuezhi; Zhou, Xiaojun

2017-11-01

This paper describes the behaviour of axially loaded long and eccentrically loaded short thin-walled steel channels, strengthened with transversely bonded carbon fibre reinforced polymer (CFRP) sheets. Seven long members, each 1400 mm long, and seven short members, each 750mmlong, were tested. The main parameters were the number of CFRP plies (one or two) and the clear spacing between the CFRP strips (50, 100 or 150 mm). The effect of CFRP sheet layer and clear spacing was studied. All the ultimate load capacity of the reinforced members was improved in different extent. A maximum strength gain of 9.13% was achieved for long members with two CFRP layers and 50 mm spacing of CFRP strips. The experimental results show that the global buckling happens to all the long specimens. For short members, the maximum strength gain of 12.1% was achieved with two CFRP layers and 50 mm spacing of CFRP strips. With the exception of the most heavily reinforced (2 plies at 50 and 100 mm), local buckling was observed prior to global buckling for short members, which was completely opposite of the control specimens. Meanwhile, when the clear spacing of CFRP strips is greater than theweb height of steel channel, the transversely bonded CFRP does not have a significant improvement in buckling load capacity of the short- and long-channel components. While the clear spacing is less than the web height, the more number of CFRP layer, the more enhancement of buckling load capacity.

Development of a three-dimensional multistage inverse design method for aerodynamic matching of axial compressor blading

NASA Astrophysics Data System (ADS)

van Rooij, Michael P. C.

Current turbomachinery design systems increasingly rely on multistage Computational Fluid Dynamics (CFD) as a means to assess performance of designs. However, design weaknesses attributed to improper stage matching are addressed using often ineffective strategies involving a costly iterative loop between blading modification, revision of design intent, and evaluation of aerodynamic performance. A design methodology is presented which greatly improves the process of achieving design-point aerodynamic matching. It is based on a three-dimensional viscous inverse design method which generates the blade camber surface based on prescribed pressure loading, thickness distribution and stacking line. This inverse design method has been extended to allow blading analysis and design in a multi-blade row environment. Blade row coupling was achieved through a mixing plane approximation. Parallel computing capability in the form of MPI has been implemented to reduce the computational time for multistage calculations. Improvements have been made to the flow solver to reach the level of accuracy required for multistage calculations. These include inclusion of heat flux, temperature-dependent treatment of viscosity, and improved calculation of stress components and artificial dissipation near solid walls. A validation study confirmed that the obtained accuracy is satisfactory at design point conditions. Improvements have also been made to the inverse method to increase robustness and design fidelity. These include the possibility to exclude spanwise sections of the blade near the endwalls from the design process, and a scheme that adjusts the specified loading area for changes resulting from the leading and trailing edge treatment. Furthermore, a pressure loading manager has been developed. Its function is to automatically adjust the pressure loading area distribution during the design calculation in order to achieve a specified design objective. Possible objectives are overall mass flow and compression ratio, and radial distribution of exit flow angle. To supplement the loading manager, mass flow inlet and exit boundary conditions have been implemented. Through appropriate combination of pressure or mass flow inflow/outflow boundary conditions and loading manager objectives, increased control over the design intent can be obtained. The three-dimensional multistage inverse design method with pressure loading manager was demonstrated to offer greatly enhanced blade row matching capabilities. Multistage design allows for simultaneous design of blade rows in a mutually interacting environment, which permits the redesigned blading to adapt to changing aerodynamic conditions resulting from the redesign. This ensures that the obtained blading geometry and performance implied by the prescribed pressure loading distribution are consistent with operation in the multi-blade row environment. The developed methodology offers high aerodynamic design quality and productivity, and constitutes a significant improvement over existing approaches used to address design-point aerodynamic matching.

Lactic acid concentrations that reduce microbial load yet minimally impact colour and sensory characteristics of beef.

PubMed

Rodríguez-Melcón, Cristina; Alonso-Calleja, Carlos; Capita, Rosa

2017-07-01

Lactic acid (LA) has recently been approved in the EU as beef decontaminant. In order to identify the most appropriate concentration, beef samples were spray-treated with LA (2%, 3%, 4% or 5%) or left untreated (control). Microbial load (aerobic plate counts, psychrotrophs and Enterobacteriaceae), pH, instrumental colour and sensory properties were investigated at 0, 24, 72 and 120h of refrigerated storage. The reductions in bacteria after spraying ranged from 0.57 to 0.95 log units. A residual antimicrobial effect was observed so that at 120h LA reduced microbial load by up to 2 log units compared with the control samples. Samples treated with 5% LA showed the lowest redness value (a*) and hedonic scores at all sampling times. Only for samples treated with 4% LA did the sensorial shelf-life limit extend beyond 120h. It is suggested that treatment of beef with 4% LA not only may improve microbiological quality, but also may enhance sensory properties and shelf-life. Copyright © 2017. Published by Elsevier Ltd.

User-Preference-Driven Model Predictive Control of Residential Building Loads and Battery Storage for Demand Response: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Xin; Baker, Kyri A.; Christensen, Dane T.

This paper presents a user-preference-driven home energy management system (HEMS) for demand response (DR) with residential building loads and battery storage. The HEMS is based on a multi-objective model predictive control algorithm, where the objectives include energy cost, thermal comfort, and carbon emission. A multi-criterion decision making method originating from social science is used to quickly determine user preferences based on a brief survey and derive the weights of different objectives used in the optimization process. Besides the residential appliances used in the traditional DR programs, a home battery system is integrated into the HEMS to improve the flexibility andmore » reliability of the DR resources. Simulation studies have been performed on field data from a residential building stock data set. Appliance models and usage patterns were learned from the data to predict the DR resource availability. Results indicate the HEMS was able to provide a significant amount of load reduction with less than 20% prediction error in both heating and cooling cases.« less

User-Preference-Driven Model Predictive Control of Residential Building Loads and Battery Storage for Demand Response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Xin; Baker, Kyri A; Isley, Steven C

This paper presents a user-preference-driven home energy management system (HEMS) for demand response (DR) with residential building loads and battery storage. The HEMS is based on a multi-objective model predictive control algorithm, where the objectives include energy cost, thermal comfort, and carbon emission. A multi-criterion decision making method originating from social science is used to quickly determine user preferences based on a brief survey and derive the weights of different objectives used in the optimization process. Besides the residential appliances used in the traditional DR programs, a home battery system is integrated into the HEMS to improve the flexibility andmore » reliability of the DR resources. Simulation studies have been performed on field data from a residential building stock data set. Appliance models and usage patterns were learned from the data to predict the DR resource availability. Results indicate the HEMS was able to provide a significant amount of load reduction with less than 20% prediction error in both heating and cooling cases.« less

Poly(2-(diethylamino)ethyl methacrylate)-based, pH-responsive, copolymeric mixed micelles for targeting anticancer drug control release.

PubMed

Chen, Quan; Li, Siheng; Feng, Zixiong; Wang, Meng; Cai, Chengzhi; Wang, Jufang; Zhang, Lijuan

2017-01-01

We have demonstrated a novel drug delivery system to improve the selectivity of the current chemotherapy by pH-responsive, polymeric micelle carriers. The micelle carriers were prepared by the self-assembly of copolymers containing the polybasic poly(2-(diethylamino) ethyl methacrylate) (PDEAEMA) block. The mixed copolymers exhibited a comparatively low critical micelle concentration (CMC; 1.95-5.25 mg/L). The resultant mixed micelles were found to be <100 nm and were used to encapsulate the anticancer drug doxorubicin (DOX) with pretty good drug-loading content (24%) and entrapment efficiency (55%). Most importantly, the micelle carrier exhibited a pH-dependent conformational conversion and promoted the DOX release at the tumorous pH. Our in vitro studies demonstrated the comparable level of DOX-loaded mixed micelle delivery into tumor cells with the free DOX (80% of the tumor cells were killed after 48 h incubation). The DOX-loaded mixed micelles were effective to inhibit the proliferation of tumor cells after prolonged incubation. Overall, the pH-responsive mixed micelle system provided desirable potential in the controlled release of anticancer therapeutics.

Combined chemo- and photo-thermal therapy delivered by multifunctional theranostic gold nanorod-loaded microcapsules

NASA Astrophysics Data System (ADS)

Chen, Haiyan; di, Yingfeng; Chen, Dan; Madrid, Kyle; Zhang, Min; Tian, Caiping; Tang, Liping; Gu, Yueqing

2015-05-01

A polyelectrolyte microcapsule-based, cancer-targeting, and controlled drug delivery system has been developed as a multifunctional theranostic agent for synergistic cancer treatment. This new system, called FA-MC@GNR, is composed of folic acid (FA)-modified, multi-layered, hollow microcapsules loaded with gold nanorods (GNRs), and undergoes thermal degradation under near infrared (NIR) light. Either an NIR dye (MPA) or anti-cancer drug (doxorubicin, DOX) was loaded into the microcapsules via physical adsorption, yielding FA-MC@GNRs/MPA or FA-MC@GNRs/DOX, both of which exhibit no obvious toxicity, high stability, and remarkably improved tumor-targeting capabilities in vivo. Utilizing the strong NIR absorption of FA-MC@GNRs/DOX, we demonstrate the system's ability to simultaneously elicit photothermal therapy and controlled chemotherapy, achieving synergistic cancer treatment both in vitro cellular and in vivo animal experiments. Our study presents a new type of multifunctional micro-carrier for the delivery of chemotherapeutic drugs and photothermal agents, which has been shown to be an effective therapeutic approach for combined cancer treatment.

Body mass index, immune status, and virological control in HIV-infected men who have sex with men.

PubMed

Blashill, Aaron J; Mayer, Kenneth H; Crane, Heidi M; Grasso, Chris; Safren, Steven A

2013-01-01

Prior cross-sectional studies have found inconsistent relationships between body mass index (BMI) and disease progression in HIV-infected individuals. Cross-sectional and longitudinal analyses were conducted on data from a sample of 864 HIV-infected men who have sex with men (MSM) obtained from a large, nationally distributed HIV clinical cohort. Of the 864 HIV-infected MSM, 394 (46%) were of normal weight, 363 (42%) were overweight, and 107 (12%) were obese at baseline. The baseline CD4 count was 493 (standard error [SE] = 9), with viral load (log10) = 2.4 (SE = .04), and 561 (65%) were virologically suppressed. Over time, controlling for viral load, highly active antiretroviral therapy (HAART) adherence, age, and race/ethnicity, overweight and obese HIV-infected men possessed higher CD4 counts than that of normal weight HIV-infected men. Further, overweight and obese men possessed lower viral loads than that of normal weight HIV-infected men. For HIV-infected MSM, in this longitudinal cohort study, possessing a heavier than normal BMI is longitudinally associated with improved immunological health.

Energy issues in microwave food processing: A review of developments and the enabling potentials of solid-state power delivery.

PubMed

Atuonwu, J C; Tassou, S A

2018-01-23

The enormous magnitude and variety of microwave applications in household, commercial and industrial food processing creates a strong motivation for improving the energy efficiency and hence, sustainability of the process. This review critically assesses key energy issues associated with microwave food processing, focusing on previous energy performance studies, energy performance metrics, standards and regulations. Factors affecting energy-efficiency are categorised into source, load and source-load matching factors. This highlights the need for highly-flexible and controllable power sources capable of receiving real-time feedback on load properties, and effecting rapid control actions to minimise reflections, heating non-uniformities and other imperfections that lead to energy losses. A case is made for the use of solid-state amplifiers as alternatives to conventional power sources, magnetrons. By a full-scale techno-economic analysis, including energy aspects, it is shown that the use of solid-state amplifiers as replacements to magnetrons is promising, not only from an energy and overall technical perspective, but also in terms of economics.

Design of crashworthy structures with controlled behavior in HCA framework

NASA Astrophysics Data System (ADS)

Bandi, Punit

The field of crashworthiness design is gaining more interest and attention from automakers around the world due to increasing competition and tighter safety norms. In the last two decades, topology and topometry optimization methods from structural optimization have been widely explored to improve existing designs or conceive new designs with better crashworthiness. Although many gradient-based and heuristic methods for topology- and topometry-based crashworthiness design are available these days, most of them result in stiff structures that are suitable only for a set of vehicle components in which maximizing the energy absorption or minimizing the intrusion is the main concern. However, there are some other components in a vehicle structure that should have characteristics of both stiffness and flexibility. Moreover, the load paths within the structure and potential buckle modes also play an important role in efficient functioning of such components. For example, the front bumper, side frame rails, steering column, and occupant protection devices like the knee bolster should all exhibit controlled deformation and collapse behavior. The primary objective of this research is to develop new methodologies to design crashworthy structures with controlled behavior. The well established Hybrid Cellular Automaton (HCA) method is used as the basic framework for the new methodologies, and compliant mechanism-type (sub)structures are the highlight of this research. The ability of compliant mechanisms to efficiently transfer force and/or motion from points of application of input loads to desired points within the structure is used to design solid and tubular components that exhibit controlled deformation and collapse behavior under crash loads. In addition, a new methodology for controlling the behavior of a structure under multiple crash load scenarios by adaptively changing the contributions from individual load cases is developed. Applied to practical design problems, the results demonstrate that the methodologies provide a practical tool to aid the design engineer in generating design concepts for crashworthy structures with controlled behavior. Although developed in the HCA framework, the basic ideas behind these methods are generic and can be easily implemented with other available topology- and topometry-based optimization methods.

From the track to the ocean: Using flow control to improve marine bio-logging tags for cetaceans

PubMed Central

Fiore, Giovani; Anderson, Erik; Garborg, C. Spencer; Murray, Mark; Johnson, Mark; Moore, Michael J.; Howle, Laurens

2017-01-01

Bio-logging tags are an important tool for the study of cetaceans, but superficial tags inevitably increase hydrodynamic loading. Substantial forces can be generated by tags on fast-swimming animals, potentially affecting behavior and energetics or promoting early tag removal. Streamlined forms have been used to reduce loading, but these designs can accelerate flow over the top of the tag. This non-axisymmetric flow results in large lift forces (normal to the animal) that become the dominant force component at high speeds. In order to reduce lift and minimize total hydrodynamic loading this work presents a new tag design (Model A) that incorporates a hydrodynamic body, a channel to reduce fluid speed differences above and below the housing and wing to redirect flow to counter lift. Additionally, three derivatives of the Model A design were used to examine the contribution of individual flow control features to overall performance. Hydrodynamic loadings of four models were compared using computational fluid dynamics (CFD). The Model A design eliminated all lift force and generated up to ~30 N of downward force in simulated 6 m/s aligned flow. The simulations were validated using particle image velocimetry (PIV) to experimentally characterize the flow around the tag design. The results of these experiments confirm the trends predicted by the simulations and demonstrate the potential benefit of flow control elements for the reduction of tag induced forces on the animal. PMID:28196148

Design of an Input-Parallel Output-Parallel LLC Resonant DC-DC Converter System for DC Microgrids

NASA Astrophysics Data System (ADS)

Juan, Y. L.; Chen, T. R.; Chang, H. M.; Wei, S. E.

2017-11-01

Compared with the centralized power system, the distributed modularized power system is composed of several power modules with lower power capacity to provide a totally enough power capacity for the load demand. Therefore, the current stress of the power components in each module can then be reduced, and the flexibility of system setup is also enhanced. However, the parallel-connected power modules in the conventional system are usually controlled to equally share the power flow which would result in lower efficiency in low loading condition. In this study, a modular power conversion system for DC micro grid is developed with 48 V dc low voltage input and 380 V dc high voltage output. However, in the developed system control strategy, the numbers of power modules enabled to share the power flow is decided according to the output power at lower load demand. Finally, three 350 W power modules are constructed and parallel-connected to setup a modular power conversion system. From the experimental results, compared with the conventional system, the efficiency of the developed power system in the light loading condition is greatly improved. The modularized design of the power system can also decrease the power loss ratio to the system capacity.

Dextran based Polymeric Micelles as Carriers for Delivery of Hydrophobic Drugs.

PubMed

Mocanu, Georgeta; Nichifor, Marieta; Sacarescu, Liviu

2017-01-01

The improvement of drugs bioavailability, especially of the hydrophobic ones, by using various nanoparticles is a very exciting field of the modern research. The applicability of nano-sized shell crosslinked micelles based on dextran as supports for controlled release of several hydrophobic drugs (nystatin, rifampicin, resveratrol, and curcumin) was investigated by in vitro drug loading/release experiments. The synthesized crosslinked micelles were loaded with drugs of various hydrophobicities and their retention/release behavior was followed by dialysis procedure. Crosslinked micelles obtained from dextran with octadecyl end groups, with or without N-(2- hydroxypropyl)-N,N-dimethyl-N-benzylammonium chloride groups attached to the main dextran chains, could retain the drugs in amounts which increased with increasing drug hydrophobicity (water insolubility), as follows: 30-60 mg rifampicin/g, 70-100 mg nystatin/g, 120-144 mg resveratrol/g and 146-260 mg curcumin/g. The rate of drug release from the loaded micelles was also dependent on the drug hydrophobicity and was always slower than the free drug recovery. Antioxidant activity of curcumin and resveratrol released from the loaded micelles was preserved. The results highlighted the potential of the new nano-sized micelles as carriers for prolonged and controlled delivery of various hydrophobic drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of vibration on muscle strength imbalance in lower extremity using multi-control whole body vibration platform.

PubMed

Yu, Chang Ho; Seo, Shin Bae; Kang, Seung Rok; Kim, Kyung; Kwon, Tae Kyu

2015-01-01

This study shows the improvement of muscle activity and muscle strength imbalance in the lower extremities through independent exercise loads in vibration platform. Twenty females of age 20 participated in this study. The subjects were divided into WBV group, with more than 10% of muscle strength imbalance between left and right the lower extremities, and control group, with less than 10% of muscle strength imbalance between left and right the lower extremities. As the prior experiment showed, different exercise postures provide different muscular activities. As a result, the highest muscular activity was found to be in the low squat posture. Therefore, the LS posture was selected for the exercise in this experiment. Vibration intensities were applied to dominant muscle and non-dominant muscle, and the vibration frequency was fixed at 25Hz for the WBV group. The control group was asked to perform the same exercise as the WBV group, without stimulated vibration. This exercise was conducted for a total of 4 weeks. As a result, the WBV group which showed an average deviation of 16% before the experiment, tended to decrease approximately to 5%. In this study, vibration exercise using load deviation is shown to be effective in improving the muscle strength imbalance.

Physical Exercise with Multicomponent Cognitive Intervention for Older Adults with Alzheimer's Disease: A 6-Month Randomized Controlled Trial

PubMed Central

Kim, Min-Ji; Han, Chang-Wan; Min, Kyoung-Youn; Cho, Chae-Yoon; Lee, Chae-Won; Ogawa, Yoshiko; Mori, Etsuro; Kohzuki, Masahiro

2016-01-01

Aims This study aimed to investigate the effect of 6-month physical exercise with a multicomponent cognitive program (MCP) on the cognitive function of older adults with moderate to severe Alzheimer's disease (AD). Methods We included 33 participants with AD in a 6-month randomized controlled trial. The intervention group participated in physical exercise and received a MCP. The control group received only the MCP. Before and after the intervention, cognitive outcomes were assessed using the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-cog), Mini-Mental State Examination, and the Clock Drawing Test. Physical performance was evaluated by exercise time, the number of pedal rotation, total load, grip strength, and the Berg Balance Scale (BBS). Results In all cognitive measures, there were no significant improvements between the two groups after 6 months in the baseline value-adjusted primary analysis. However, the ADAS-cog score was significantly lower between the two groups in secondary analysis adjusted for baseline value, age, sex, and education years. All physical outcomes were significantly higher in the intervention group except for total load compared with baseline measurements. Conclusion This study indicates that it is possible to improve cognitive function in older adults with moderate to severe AD through 6-month physical exercise with a multicomponent cognitive intervention. PMID:27403134

A numerical and experimental study on optimal design of multi-DOF viscoelastic supports for passive vibration control in rotating machinery

NASA Astrophysics Data System (ADS)

Ribeiro, Eduardo Afonso; Lopes, Eduardo Márcio de Oliveira; Bavastri, Carlos Alberto

2017-12-01

Viscoelastic materials have played an important role in passive vibration control. Nevertheless, the use of such materials in supports of rotating machines, aiming at controlling vibration, is more recent, mainly when these supports present additional complexities like multiple degrees of freedom and require accurate models to predict the dynamic behavior of viscoelastic materials working in a broad band of frequencies and temperatures. Previously, the authors propose a methodology for an optimal design of viscoelastic supports (VES) for vibration suppression in rotordynamics, which improves the dynamic prediction accuracy, the speed calculation, and the modeling of VES as complex structures. However, a comprehensive numerical study of the dynamics of rotor-VES systems, regarding the types and combinations of translational and rotational degrees of freedom (DOFs), accompanied by the corresponding experimental validation, is still lacking. This paper presents such a study considering different types and combinations of DOFs in addition to the simulation of their number of additional masses/inertias, as well as the kind and association of the applied viscoelastic materials (VEMs). The results - regarding unbalance frequency response, transmissibility and displacement due to static loads - lead to: 1) considering VES as complex structures which allow improving the efficacy in passive vibration control; 2) acknowledging the best configuration concerning DOFs and VEM choice and association for a practical application concerning passive vibration control and load resistance. The specific outcomes of the conducted experimental validation attest the accuracy of the proposed methodology.

Reduction of Helicopter BVI Noise, Vibration, and Power Consumption Through Individual Blade Control

NASA Technical Reports Server (NTRS)

Jacklin, Stephen A.; Blaas, Achim; Teves, Dietrich; Kube, Roland; Warmbrodt, William (Technical Monitor)

1994-01-01

A wind tunnel test was conducted with a full-scale BO 105 helicopter rotor to evaluate the potential of open-loop individual blade control (IBC) to improve rotor performance, to reduce blade vortex interaction (BVI) noise, and to alleviate helicopter vibrations. The wind tunnel test was an international collaborative effort between NASA/U.S. Army AFDD, ZF Luftfahrttechnik, Eurocopter Deutschland, and the German Aerospace Laboratory (DLR) and was conducted under the auspices of the U.S./German MOU on Rotorcraft Aeromechanics. In this test the normal blade pitch links of the rotor were replaced by servo-actuators so that the pitch of each blade could be controlled independently of the other blades. The specially designed servoactuators and IBC control system were designed and manufactured by ZF Luftfahrttechnik, GmbH. The wind tunnel test was conducted in the 40- by 80-Foot Wind Tunnel at the NASA Ames Research Center. An extensive amount of measurement information was acquired for each IBC data point. These data include rotor performance, static and dynamic hub forces and moments, rotor loads, control loads, inboard and outboard blade pitch motion, and BVI noise data. The data indicated very significant (80 percent) simultaneous reductions in both BVI noise and hub vibrations could be obtained using multi-harmonic input at the critical descent (terminal approach) condition. The data also showed that performance improvements of up to 7 percent could be obtained using 2P input at high-speed forward flight conditions.

Development of an Optimal Controller and Validation Test Stand for Fuel Efficient Engine Operation

NASA Astrophysics Data System (ADS)

Rehn, Jack G., III

There are numerous motivations for improvements in automotive fuel efficiency. As concerns over the environment grow at a rate unmatched by hybrid and electric automotive technologies, the need for reductions in fuel consumed by current road vehicles has never been more present. Studies have shown that a major cause of poor fuel consumption in automobiles is improper driving behavior, which cannot be mitigated by purely technological means. The emergence of autonomous driving technologies has provided an opportunity to alleviate this inefficiency by removing the necessity of a driver. Before autonomous technology can be relied upon to reduce gasoline consumption on a large scale, robust programming strategies must be designed and tested. The goal of this thesis work was to design and deploy an autonomous control algorithm to navigate a four cylinder, gasoline combustion engine through a series of changing load profiles in a manner that prioritizes fuel efficiency. The experimental setup is analogous to a passenger vehicle driving over hilly terrain at highway speeds. The proposed approach accomplishes this using a model-predictive, real-time optimization algorithm that was calibrated to the engine. Performance of the optimal control algorithm was tested on the engine against contemporary cruise control. Results indicate that the "efficient'' strategy achieved one to two percent reductions in total fuel consumed for all load profiles tested. The consumption data gathered also suggests that further improvements could be realized on a different subject engine and using extended models and a slightly modified optimal control approach.

Satellite control of electric power distribution

NASA Technical Reports Server (NTRS)

Bergen, L.

1981-01-01

An L-band frequencies satellite link providing the medium for direct control of electrical loads at individual customer sites from remote central locations is described. All loads supplied under interruptible-service contracts are likely condidates for such control, and they can be cycled or switched off to reduce system loads. For every kW of load eliminated or deferred to off-peak hours, the power company reduces its need for additional generating capacity. In addition, the satellite could switch meter registers so that their readings automatically reflected the time of consumption. The system would perform load-shedding operations during emergencies, disconnecting large blocks of load according to predetermined priorities. Among the distribution operations conducted by the satellite in real time would be: load reconfiguration, voltage regulation, fault isolation, and capacitor and feeder load control.

Assessment of Optimal Flexibility in Ensemble of Frequency Responsive Loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kundu, Soumya; Hansen, Jacob; Lian, Jianming

2018-04-19

Potential of electrical loads in providing grid ancillary services is often limited due to the uncertainties associated with the load behavior. A knowledge of the expected uncertainties with a load control program would invariably yield to better informed control policies, opening up the possibility of extracting the maximal load control potential without affecting grid operations. In the context of frequency responsive load control, a probabilistic uncertainty analysis framework is presented to quantify the expected error between the target and actual load response, under uncertainties in the load dynamics. A closed-form expression of an optimal demand flexibility, minimizing the expected errormore » in actual and committed flexibility, is provided. Analytical results are validated through Monte Carlo simulations of ensembles of electric water heaters.« less

Load theory of selective attention and cognitive control.

PubMed

Lavie, Nilli; Hirst, Aleksandra; de Fockert, Jan W; Viding, Essi

2004-09-01

A load theory of attention in which distractor rejection depends on the level and type of load involved in current processing was tested. A series of experiments demonstrates that whereas high perceptual load reduces distractor interference, working memory load or dual-task coordination load increases distractor interference. These findings suggest 2 selective attention mechanisms: a perceptual selection mechanism serving to reduce distractor perception in situations of high perceptual load that exhaust perceptual capacity in processing relevant stimuli and a cognitive control mechanism that reduces interference from perceived distractors as long as cognitive control functions are available to maintain current priorities (low cognitive load). This theory resolves the long-standing early versus late selection debate and clarifies the role of cognitive control in selective attention. ((c) 2004 APA, all rights reserved)

Effects of a mobile phone short message service on antiretroviral treatment adherence in Kenya (WelTel Kenya1): a randomised trial.

PubMed

Lester, Richard T; Ritvo, Paul; Mills, Edward J; Kariri, Antony; Karanja, Sarah; Chung, Michael H; Jack, William; Habyarimana, James; Sadatsafavi, Mohsen; Najafzadeh, Mehdi; Marra, Carlo A; Estambale, Benson; Ngugi, Elizabeth; Ball, T Blake; Thabane, Lehana; Gelmon, Lawrence J; Kimani, Joshua; Ackers, Marta; Plummer, Francis A

2010-11-27

Mobile (cell) phone communication has been suggested as a method to improve delivery of health services. However, data on the effects of mobile health technology on patient outcomes in resource-limited settings are limited. We aimed to assess whether mobile phone communication between health-care workers and patients starting antiretroviral therapy in Kenya improved drug adherence and suppression of plasma HIV-1 RNA load. WelTel Kenya1 was a multisite randomised clinical trial of HIV-infected adults initiating antiretroviral therapy (ART) in three clinics in Kenya. Patients were randomised (1:1) by simple randomisation with a random number generating program to a mobile phone short message service (SMS) intervention or standard care. Patients in the intervention group received weekly SMS messages from a clinic nurse and were required to respond within 48 h. Randomisation, laboratory assays, and analyses were done by investigators masked to treatment allocation; however, study participants and clinic staff were not masked to treatment. Primary outcomes were self-reported ART adherence (>95% of prescribed doses in the past 30 days at both 6 and 12 month follow-up visits) and plasma HIV-1 viral RNA load suppression (<400 copies per mL) at 12 months. The primary analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, NCT00830622. Between May, 2007, and October, 2008, we randomly assigned 538 participants to the SMS intervention (n=273) or to standard care (n=265). Adherence to ART was reported in 168 of 273 patients receiving the SMS intervention compared with 132 of 265 in the control group (relative risk [RR] for non-adherence 0·81, 95% CI 0·69-0·94; p=0·006). Suppressed viral loads were reported in 156 of 273 patients in the SMS group and 128 of 265 in the control group, (RR for virologic failure 0·84, 95% CI 0·71-0·99; p=0·04). The number needed to treat (NNT) to achieve greater than 95% adherence was nine (95% CI 5·0-29·5) and the NNT to achieve viral load suppression was 11 (5·8-227·3). Patients who received SMS support had significantly improved ART adherence and rates of viral suppression compared with the control individuals. Mobile phones might be effective tools to improve patient outcome in resource-limited settings. US President's Emergency Plan for AIDS Relief. Copyright © 2010 Elsevier Ltd. All rights reserved.

Split radiator design for heat rejection optimization for a waste heat recovery system

DOEpatents

Ernst, Timothy C.; Nelson, Christopher R.

2016-10-18

A cooling system provides improved heat recovery by providing a split core radiator for both engine cooling and condenser cooling for a Rankine cycle (RC). The cooling system includes a radiator having a first cooling core portion and a second cooling core portion. An engine cooling loop is fluidly connected the second cooling core portion. A condenser of an RC has a cooling loop fluidly connected to the first cooling core portion. A valve is provided between the engine cooling loop and the condenser cooling loop adjustably control the flow of coolant in the condenser cooling loop into the engine cooling loop. The cooling system includes a controller communicatively coupled to the valve and adapted to determine a load requirement for the internal combustion engine and adjust the valve in accordance with the engine load requirement.

The relative contributions of processing speed and cognitive load to working memory accuracy in multiple sclerosis.

PubMed

Leavitt, Victoria M; Lengenfelder, Jean; Moore, Nancy B; Chiaravalloti, Nancy D; DeLuca, John

2011-06-01

Cognitive symptoms of multiple sclerosis (MS) include processing-speed deficits and working memory impairment. The precise manner in which these deficits interact in individuals with MS remains to be explicated. We hypothesized that providing more time on a complex working memory task would result in performance benefits for individuals with MS relative to healthy controls. Fifty-three individuals with clinically definite MS and 36 matched healthy controls performed a computerized task that systematically manipulated cognitive load. The interval between stimuli presentations was manipulated to provide increasing processing time. The results confirmed that individuals with MS who have processing-speed deficits significantly improve in performance accuracy when given additional time to process the information in working memory. Implications of these findings for developing appropriate cognitive rehabilitation interventions are discussed.

Biomechanical Modeling of the Deadlift Exercise to Improve the Efficacy of Resistive Exercise Microgravity Countermeasures

NASA Technical Reports Server (NTRS)

Jagodnik, K. M.; Thompson, W. K.; Gallo, C. A.; DeWitt, J. K.; Funk, J. H.; Funk, N. W.; Perusek, G. P.; Sheehan, C. C.; Lewandowski, B. E.

2016-01-01

During long-duration spaceflight missions, astronauts exposure to microgravity without adequate countermeasures can result in losses of muscular strength and endurance, as well as loss of bone mass. As a countermeasure to this challenge, astronauts engage in resistive exercise during spaceflight to maintain their musculoskeletal function. The Hybrid Ultimate Lifting Kit (HULK) has been designed as a prototype exercise device for an exploration-class vehicle; the HULK features a much smaller footprint than previous devices such as the Advanced Resistive Exercise Device (ARED) on the International Space Station (ISS), which makes the HULK suitable for extended spaceflight missions in vehicles with limited volume. As current ISS exercise countermeasure equipment represents an improvement over previous generations of such devices, the ARED is being employed as a benchmark of functional performance. This project involves the development of a biomechanical model of the deadlift exercise, and is novel in that it is the first exercise analyzed in this context to include the upper limbs in the loading path, in contrast to the squat, single-leg squat, and heel raise exercises also being modeled by our team. OpenSim software is employed to develop these biomechanical models of humans performing resistive exercises to assess and improve the new exercise device designs. Analyses include determining differences in joint and muscle forces when using different loading strategies with the device, comparing and contrasting with the ARED benchmark, and determining whether the loading is sufficient to maintain musculoskeletal health. During data collection, the number of repetitions, load, cadence, stance, and grip width are controlled in order to facilitate comparisons between loading configurations. To date, data have been collected for two human subjects performing the deadlift exercise on the HULK device using two different loading conditions. Recorded data include motion capture, electromyography (EMG), ground reaction forces, device load cell data, photos and videos, and anthropometric data. Work is ongoing to perform biomechanical analyses including inverse kinematics and inverse dynamics to compare different versions of the deadlift model in order to determine which provides an appropriate level of detail to study this exercise. This work is supported by the National Space Biomedical Research Institute through NCC 9-58.

Guided waves by axisymmetric and non-axisymmetric surface loading on hollow cylinders

PubMed

Shin; Rose

1999-06-01

Guided waves generated by axisymmetric and non-axisymmetric surface loading on a hollow cylinder are studied. For the theoretical analysis of the superposed guided waves, a normal mode concept is employed. The amplitude factors of individual guided wave modes are studied with respect to varying surface pressure loading profiles. Both theoretical and experimental focus is given to the guided waves generated by both axisymmetric and non-axisymmetric excitation. For the experiments, a comb transducer and high power tone burst function generator system are used on a sample Inconel tube. Surface loading conditions, such as circumferential loading angles and axial loading lengths, are used with the frequency and phase velocity to control the axisymmetric and non-axisymmetric mode excitations. The experimental study demonstrates the use of a practical non-axisymmetric partial loading technique in generating axisymmetric modes, particularly useful in the inspection of tubing and piping with limited circumferential access. From both theoretical and experimental studies, it also could be said that the amount of flexural modes reflected from a defect contains information on the reflector's circumferential angle, as well as potentially other classification and sizing feature information. The axisymmetric and non-axisymmetric guided wave modes should both be carefully considered for improvement of the overall analysis of guided waves generated in hollow cylinders.

Load power device, system and method of load control and management employing load identification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Yi; Luebke, Charles John; Schoepf, Thomas J.

A load power device includes a power input, at least one power output for at least one load, a plurality of sensors structured to sense voltage and current at the at least one power output, and a processor. The processor provides: (a) load identification based upon the sensed voltage and current, and (b) load control and management based upon the load identification.

Optimal Control Allocation with Load Sensor Feedback for Active Load Suppression

NASA Technical Reports Server (NTRS)

Miller, Christopher

2017-01-01

These slide sets describe the OCLA formulation and associated algorithms as a set of new technologies in the first practical application of load limiting flight control utilizing load feedback as a primary control measurement. Slide set one describes Experiment Development and slide set two describes Flight-Test Performance.

Modal space three-state feedback control for electro-hydraulic servo plane redundant driving mechanism with eccentric load decoupling.

PubMed

Zhao, Jinsong; Wang, Zhipeng; Zhang, Chuanbi; Yang, Chifu; Bai, Wenjie; Zhao, Zining

2018-06-01

The shaking table based on electro-hydraulic servo parallel mechanism has the advantage of strong carrying capacity. However, the strong coupling caused by the eccentric load not only affects the degree of freedom space control precision, but also brings trouble to the system control. A novel decoupling control strategy is proposed, which is based on modal space to solve the coupling problem for parallel mechanism with eccentric load. The phenomenon of strong dynamic coupling among degree of freedom space is described by experiments, and its influence on control design is discussed. Considering the particularity of plane motion, the dynamic model is built by Lagrangian method to avoid complex calculations. The dynamic equations of the coupling physical space are transformed into the dynamic equations of the decoupling modal space by using the weighted orthogonality of the modal main mode with respect to mass matrix and stiffness matrix. In the modal space, the adjustments of the modal channels are independent of each other. Moreover, the paper discusses identical closed-loop dynamic characteristics of modal channels, which will realize decoupling for degree of freedom space, thus a modal space three-state feedback control is proposed to expand the frequency bandwidth of each modal channel for ensuring their near-identical responses in a larger frequency range. Experimental results show that the concept of modal space three-state feedback control proposed in this paper can effectively reduce the strong coupling problem of degree of freedom space channels, which verify the effectiveness of the proposed model space state feedback control strategy for improving the control performance of the electro-hydraulic servo plane redundant driving mechanism. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Testing of a controller for a hybrid capillary pumped loop thermal control system

NASA Technical Reports Server (NTRS)

Schweickart, Russell; Ottenstein, Laura; Cullimore, Brent; Egan, Curtis; Wolf, Dave

1989-01-01

A controller for a series hybrid capillary pumped loop (CPL) system that requires no moving parts does not resrict fluid flow has been tested and has demonstrated improved performance characteristics over a plain CPL system and simple hybrid CPL systems. These include heat load sharing, phase separation, self-regulated flow control and distribution, all independent of most system pressure drop. In addition, the controlled system demonstrated a greater heat transport capability than the simple CPL system but without the large fluid inventory requirement of the hybrid systems. A description of the testing is presented along with data that show the advantages of the system.

PSO Algorithm for an Optimal Power Controller in a Microgrid

NASA Astrophysics Data System (ADS)

Al-Saedi, W.; Lachowicz, S.; Habibi, D.; Bass, O.

2017-07-01

This paper presents the Particle Swarm Optimization (PSO) algorithm to improve the quality of the power supply in a microgrid. This algorithm is proposed for a real-time selftuning method that used in a power controller for an inverter based Distributed Generation (DG) unit. In such system, the voltage and frequency are the main control objectives, particularly when the microgrid is islanded or during load change. In this work, the PSO algorithm is implemented to find the optimal controller parameters to satisfy the control objectives. The results show high performance of the applied PSO algorithm of regulating the microgrid voltage and frequency.

Improving the yield from fermentative hydrogen production.

PubMed

Kraemer, Jeremy T; Bagley, David M

2007-05-01

Efforts to increase H(2) yields from fermentative H(2) production include heat treatment of the inoculum, dissolved gas removal, and varying the organic loading rate. Although heat treatment kills methanogens and selects for spore-forming bacteria, the available evidence indicates H(2) yields are not maximized compared to bromoethanesulfonate, iodopropane, or perchloric acid pre-treatments and spore-forming acetogens are not killed. Operational controls (low pH, short solids retention time) can replace heat treatment. Gas sparging increases H(2) yields compared to un-sparged reactors, but no relationship exists between the sparging rate and H(2) yield. Lower sparging rates may improve the H(2) yield with less energy input and product dilution. The reasons why sparging improves H(2) yields are unknown, but recent measurements of dissolved H(2) concentrations during sparging suggest the assumption of decreased inhibition of the H(2)-producing enzymes is unlikely. Significant disagreement exists over the effect of organic loading rate (OLR); some studies show relatively higher OLRs improve H(2) yield while others show the opposite. Discovering the reasons for higher H(2) yields during dissolved gas removal and changes in OLR will help improve H(2) yields.

Field Testing of LIDAR-Assisted Feedforward Control Algorithms for Improved Speed Control and Fatigue Load Reduction on a 600-kW Wind Turbine: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Avishek A.; Bossanyi, Ervin A.; Scholbrock, Andrew K.

2015-12-14

A severe challenge in controlling wind turbines is ensuring controller performance in the presence of a stochastic and unknown wind field, relying on the response of the turbine to generate control actions. Recent technologies such as LIDAR, allow sensing of the wind field before it reaches the rotor. In this work a field-testing campaign to test LIDAR Assisted Control (LAC) has been undertaken on a 600-kW turbine using a fixed, five-beam LIDAR system. The campaign compared the performance of a baseline controller to four LACs with progressively lower levels of feedback using 35 hours of collected data.

Improvement of the Measurement Range and Temperature Characteristics of a Load Sensor Using a Quartz Crystal Resonator with All Crystal Layer Components.

PubMed

Murozaki, Yuichi; Sakuma, Shinya; Arai, Fumihito

2017-05-08

Monitoring multiple biosignals, such as heart rate, respiration cycle, and weight transitions, contributes to the health management of individuals. Specifically, it is possible to measure multiple biosignals using load information obtained through contact with the environment, such as a chair and bed, in daily use. A wide-range load sensor is essential since load information contains multiple biosignals with various load ranges. In this study, a load sensor is presented by using a quartz crystal resonator (QCR) with a wide measurement range of 1.5 × 10⁶ (0.4 mN to 600 N), and its temperature characteristic of load is improved to -7 Hz/°C (-18 mN/°C). In order to improve the measurement range of the load, a design method of this sensor is proposed by restraining the buckling of QCR and by using a thinner QCR. The proposed sensor allows a higher allowable load with high sensitivity. The load sensor mainly consists of three layers, namely a QCR layer and two holding layers. As opposed to the conventional holding layer composed of silicon, quartz crystal is utilized for the holding layers to improve the temperature characteristic of the load sensor. In the study, multiple biosignals, such as weight and pulse, are detected by using a fabricated sensor.

Rolling Maneuver Load Alleviation using active controls

NASA Technical Reports Server (NTRS)

Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

1992-01-01

Rolling Maneuver Load Alleviation (RMLA) has been demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the NASA Langley Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and actuation of the trailing edge inboard control surface pairs to maintain roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of 0.33, .38 and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

Fracture prevention by prophylactic femoroplasty of the proximal femur--metallic compared with cemented augmentation.

PubMed

Springorum, Hans-Robert; Gebauer, Matthias; Mehrl, Alexander; Stark, Olaf; Craiovan, Benjamin; Püschel, Klaus; Amling, Michael; Grifka, Joachim; Beckmann, Johannes

2014-07-01

To compare 2 different femoral neck augmentation techniques at improving the mechanical strength of the femoral neck. Twenty pairs of human cadaveric femora were randomly divided into 2 groups. In 1 group, the femora were augmented with a steel spiral; the other group with the cemented technique. The untreated contralateral side served as an intraindividual control. Fracture strength was evaluated using an established biomechanical testing scenario mimicking a fall on the greater trochanter (Hayes fall). The peak load to failure was significantly higher in the steel spiral group (P = 0.0024) and in the cemented group (P = 0.001) compared with the intraindividual controls. The peak load to failure showed a median of 3167 N (1825-5230 N) in the spiral group and 2485 N (1066-4395 N) in the spiral control group. The peak load to failure in the cemented group was 3698 N (SD ± 1249 N) compared with 2763 N (SD ± 1335 N) in the cement control group. Furthermore, fracture displacement was clearly reduced in the steel spiral group. Femoral augmentations using steel spirals or cement-based femoroplasty are technically feasible procedures. Our results demonstrate that a prophylactic reinforced proximal femur has higher strength when compared with the untreated contralateral limb. Prophylactic augmentation has potential to become an auxiliary treatment option to protect the osteoporotic proximal femur against fracture.

Superconducting magnetic energy storage for asynchronous electrical systems

DOEpatents

Boenig, Heinrich J.

1986-01-01

A superconducting magnetic energy storage coil connected in parallel between converters of two or more ac power systems provides load leveling and stability improvement to any or all of the ac systems. Control is provided to direct the charging and independently the discharging of the superconducting coil to at least a selected one of the ac power systems.

Analysis of improved criteria for mold growth in ASHRAE standard 160 by comparison with field observations

Treesearch

Samuel V. Glass; Stanley D. Gatland II; Kohta Ueno; Christopher J. Schumacher

2017-01-01

ASHRAE Standard 160, Criteria for Moisture-Control Design Analysis in Buildings, was published in 2009. The standard sets criteria for moisture design loads, hygrothermal analysis methods, and satisfactory moisture performance of the building envelope. One of the evaluation criteria specifies conditions necessary to avoid mold growth. The current standard requires that...

Using multi-trait and random regression models to identify genetic variation in tolerance of pigs to Porcine Reproductive and Respiratory Syndrome virus

USDA-ARS?s Scientific Manuscript database

Background A host can adopt two response strategies to infection: resistance (reduce pathogen load) and tolerance (minimize impact of infection on performance). Both strategies may be under genetic control and could thus be targeted for genetic improvement. Although there is evidence in support of a...

Optimal Load-Side Control for Frequency Regulation in Smart Grids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Changhong; Mallada, Enrique; Low, Steven

Frequency control rebalances supply and demand while maintaining the network state within operational margins. It is implemented using fast ramping reserves that are expensive and wasteful, and which are expected to become increasingly necessary with the current acceleration of renewable penetration. The most promising solution to this problem is the use of demand response, i.e., load participation in frequency control. Yet it is still unclear how to efficiently integrate load participation without introducing instabilities and violating operational constraints. In this paper, we present a comprehensive load-side frequency control mechanism that can maintain the grid within operational constraints. In particular, ourmore » controllers can rebalance supply and demand after disturbances, restore the frequency to its nominal value, and preserve interarea power flows. Furthermore, our controllers are distributed (unlike the currently implemented frequency control), can allocate load updates optimally, and can maintain line flows within thermal limits. We prove that such a distributed load-side control is globally asymptotically stable and robust to unknown load parameters. We illustrate its effectiveness through simulations.« less

A multi-mode operation control strategy for flexible microgrid based on sliding-mode direct voltage and hierarchical controls.

PubMed

Zhang, Qinjin; Liu, Yancheng; Zhao, Youtao; Wang, Ning

2016-03-01

Multi-mode operation and transient stability are two problems that significantly affect flexible microgrid (MG). This paper proposes a multi-mode operation control strategy for flexible MG based on a three-layer hierarchical structure. The proposed structure is composed of autonomous, cooperative, and scheduling controllers. Autonomous controller is utilized to control the performance of the single micro-source inverter. An adaptive sliding-mode direct voltage loop and an improved droop power loop based on virtual negative impedance are presented respectively to enhance the system disturbance-rejection performance and the power sharing accuracy. Cooperative controller, which is composed of secondary voltage/frequency control and phase synchronization control, is designed to eliminate the voltage/frequency deviations produced by the autonomous controller and prepare for grid connection. Scheduling controller manages the power flow between the MG and the grid. The MG with the improved hierarchical control scheme can achieve seamless transitions from islanded to grid-connected mode and have a good transient performance. In addition the presented work can also optimize the power quality issues and improve the load power sharing accuracy between parallel VSIs. Finally, the transient performance and effectiveness of the proposed control scheme are evaluated by theoretical analysis and simulation results. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Building Energy Management Open Source Software

DOE Office of Scientific and Technical Information (OSTI.GOV)

This is the repository for Building Energy Management Open Source Software (BEMOSS), which is an open source operating system that is engineered to improve sensing and control of equipment in small- and medium-sized commercial buildings. BEMOSS offers the following key features: (1) Open source, open architecture – BEMOSS is an open source operating system that is built upon VOLTTRON – a distributed agent platform developed by Pacific Northwest National Laboratory (PNNL). BEMOSS was designed to make it easy for hardware manufacturers to seamlessly interface their devices with BEMOSS. Software developers can also contribute to adding additional BEMOSS functionalities and applications.more » (2) Plug & play – BEMOSS was designed to automatically discover supported load controllers (including smart thermostats, VAV/RTUs, lighting load controllers and plug load controllers) in commercial buildings. (3) Interoperability – BEMOSS was designed to work with load control devices form different manufacturers that operate on different communication technologies and data exchange protocols. (4) Cost effectiveness – Implementation of BEMOSS deemed to be cost-effective as it was built upon a robust open source platform that can operate on a low-cost single-board computer, such as Odroid. This feature could contribute to its rapid deployment in small- or medium-sized commercial buildings. (5) Scalability and ease of deployment – With its multi-node architecture, BEMOSS provides a distributed architecture where load controllers in a multi-floor and high occupancy building could be monitored and controlled by multiple single-board computers hosting BEMOSS. This makes it possible for a building engineer to deploy BEMOSS in one zone of a building, be comfortable with its operation, and later on expand the deployment to the entire building to make it more energy efficient. (6) Ability to provide local and remote monitoring – BEMOSS provides both local and remote monitoring ability with role-based access control. (7) Security – In addition to built-in security features provided by VOLTTRON, BEMOSS provides enhanced security features, including BEMOSS discovery approval process, encrypted core-to-node communication, thermostat anti-tampering feature and many more. (8) Support from the Advisory Committee – BEMOSS was developed in consultation with an advisory committee from the beginning of the project. BEMOSS advisory committee comprises representatives from 22 organizations from government and industry.« less

Monitoring Wind Turbine Loading Using Power Converter Signals

NASA Astrophysics Data System (ADS)

Rieg, C. A.; Smith, C. J.; Crabtree, C. J.

2016-09-01

The ability to detect faults and predict loads on a wind turbine drivetrain's mechanical components cost-effectively is critical to making the cost of wind energy competitive. In order to investigate whether this is possible using the readily available power converter current signals, an existing permanent magnet synchronous generator based wind energy conversion system computer model was modified to include a grid-side converter (GSC) for an improved converter model and a gearbox. The GSC maintains a constant DC link voltage via vector control. The gearbox was modelled as a 3-mass model to allow faults to be included. Gusts and gearbox faults were introduced to investigate the ability of the machine side converter (MSC) current (I q) to detect and quantify loads on the mechanical components. In this model, gearbox faults were not detectable in the I q signal due to shaft stiffness and damping interaction. However, a model that predicts the load change on mechanical wind turbine components using I q was developed and verified using synthetic and real wind data.

A Novel Repair Method for Radial Tears of the Medial Meniscus: Biomechanical Comparison of Transtibial 2-Tunnel and Double Horizontal Mattress Suture Techniques Under Cyclic Loading.

PubMed

Bhatia, Sanjeev; Civitarese, David M; Turnbull, Travis Lee; LaPrade, Christopher M; Nitri, Marco; Wijdicks, Coen A; LaPrade, Robert F

2016-03-01

Complete radial tears of the medial meniscus have been reported to be functionally similar to a total meniscectomy. At present, there is no consensus on an ideal technique for repair of radial midbody tears of the medial meniscus. Prior attempts at repair with double horizontal mattress suture techniques have led to a reportedly high rate of incomplete healing or healing in a nonanatomic (gapped) position, which compromises the ability of the meniscus to withstand hoop stresses. A newly proposed 2-tunnel radial meniscal repair method will result in decreased gapping and increased ultimate failure loads compared with the double horizontal mattress suture repair technique under cyclic loading. Controlled laboratory study. Ten matched pairs of male human cadaveric knees (average age, 58.6 years; range, 48-66 years) were used. A complete radial medial meniscal tear was made at the junction of the posterior one-third and middle third of the meniscus. One knee underwent a horizontal mattress inside-out repair, while the contralateral knee underwent a radial meniscal repair entailing the same technique with a concurrent novel 2-tunnel repair. Specimens were potted and mounted on a universal testing machine. Each specimen was cyclically loaded 1000 times with loads between 5 and 20 N before experiencing a load to failure. Gap distances at the tear site and failure load were measured. The 2-tunnel repairs exhibited a significantly stronger ultimate failure load (median, 196 N; range, 163-212 N) than did the double horizontal mattress suture repairs (median, 106 N; range, 63-229 N) (P = .004). In addition, the 2-tunnel repairs demonstrated decreased gapping at all testing states (P < .05) with a final measured gapping of 1.7 mm and 4.1 mm after 1000 cycles for the 2-tunnel and double horizontal mattress suture repairs, respectively. The 2-tunnel repairs displayed significantly less gapping distance after cyclic loading and had significantly stronger ultimate failure loads compared with the double horizontal mattress suture repairs. Complete radial tears of the medial meniscus significantly decrease the ability of the meniscus to dissipate tibiofemoral loads, predisposing patients to early osteoarthritis. Improving the ability to repair medial meniscal radial tears in a way that withstands cyclic loads and heals in an anatomic position could significantly improve patient healing rates and result in improved preservation of the articular cartilage of the medial compartment of the knee. The 2-tunnel repair may be a more reliable and stronger repair option for midbody radial tears of the medial meniscus. Clinical studies are warranted to further evaluate these repairs. © 2015 The Author(s).

Design and Implementation of a Thermal Load Reduction System for a Hyundai Sonata PHEV for Improved Range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rugh, John P; Kreutzer, Cory J; Scott, Matthew

Increased adoption of electric-drive vehicles requires overcoming hurdles including limited vehicle range. Vehicle cabin heating and cooling demand for occupant climate control requires energy from the main battery and has been shown to significantly degrade vehicle range. During peak cooling and heating conditions, climate control can require as much as or more energy than propulsion. As part of an ongoing project, the National Renewable Energy Laboratory and project partners Hyundai America Technical Center, Inc., Gentherm, Pittsburgh Glass Works, PPG Industries, Sekisui, 3 M, and Hanon Systems developed a thermal load reduction system to reduce the range penalty associated with electricmore » vehicle climate control. Solar reflective paint, solar control glass, heated and cooled/ventilated seats, heated surfaces, and a heated windshield with door demisters were integrated into a Hyundai Sonata plug-in hybrid electric vehicle. Cold weather field-testing was conducted in Fairbanks, Alaska, and warm weather testing was conducted in Death Valley, California, to assess the system performance in comparison to the baseline production vehicle. In addition, environmental chamber testing at peak heating and cooling conditions was performed to assess the performance of the system in standardized conditions compared to the baseline. Experimental results are presented in this paper, providing quantitative data to automobile manufacturers on the impact of climate control thermal load reduction technologies to increase the advanced thermal technology adoption and market penetration of electric drive vehicles.« less

Electrically heated particulate matter filter soot control system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonze, Eugene V.; Paratore, Jr., Michael J.; Bhatia, Garima

A regeneration system includes a particulate matter (PM) filter with an upstream end for receiving exhaust gas and a downstream end. A control module determines a current soot loading level of the PM filter and compares the current soot loading level to a predetermined soot loading level. The control module permits regeneration of the PM filter when the current soot loading level is less than the predetermined soot loading level.

Power controller 28Vdc load switching (N. O. SPST). Final report, 31 August 1977-21 January 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMackin, J.B.

1980-01-21

A solid state power controller has been designed in four ratings to switch 28Vdc power to selected loads upon remote command. The four ratings trip out at currents of 10, 5, 2 and 1/2 amps. The design allows for wide variations in load and supply voltage and will not trip out on short load transients of up to 1000% of rated load current. In case of failure of the controller circuitry, an internal fuse protects the load from excessive current. The control current which operates the controller also provides a sensing function so that the state of the controller canmore » be determined remotely. The controllers are designed to operate over a case temperature range of -54 C to 120 C. A quantity of 100 units have been fabricated, tested, and supplied to the Navy.« less

Androgynous, Reconfigurable Closed Loop Feedback Controlled Low Impact Docking System With Load Sensing Electromagnetic Capture Ring

NASA Technical Reports Server (NTRS)

Lewis, James L. (Inventor); Carroll, Monty B. (Inventor); Morales, Ray H. (Inventor); Le, Thang D. (Inventor)

2002-01-01

The present invention relates to a fully androgynous, reconfigurable closed loop feedback controlled low impact docking system with load sensing electromagnetic capture ring. The docking system of the present invention preferably comprises two Docking- assemblies, each docking assembly comprising a load sensing ring having an outer face, one of more electromagnets, one or more load cells coupled to said load sensing ring. The docking assembly further comprises a plurality of actuator arms coupled to said load sensing ring and capable of dynamically adjusting the orientation of said load sensing ring and a reconfigurable closed loop control system capable of analyzing signals originating from said plurality of load cells and of outputting real time control for each of the actuators. The docking assembly of the present invention incorporates an active load sensing system to automatically dynamically adjust the load sensing ring during capture instead of requiring significant force to push and realign the ring.

NASA/FAA general aviation crash dynamics program

NASA Technical Reports Server (NTRS)

Thomson, R. G.; Hayduk, R. J.; Carden, H. D.

1981-01-01

The program involves controlled full scale crash testing, nonlinear structural analyses to predict large deflection elastoplastic response, and load attenuating concepts for use in improved seat and subfloor structure. Both analytical and experimental methods are used to develop expertise in these areas. Analyses include simplified procedures for estimating energy dissipating capabilities and comprehensive computerized procedures for predicting airframe response. These analyses are developed to provide designers with methods for predicting accelerations, loads, and displacements on collapsing structure. Tests on typical full scale aircraft and on full and subscale structural components are performed to verify the analyses and to demonstrate load attenuating concepts. A special apparatus was built to test emergency locator transmitters when attached to representative aircraft structure. The apparatus is shown to provide a good simulation of the longitudinal crash pulse observed in full scale aircraft crash tests.

[Research on pollution load of sediments in storm sewer in Beijing district].

PubMed

Li, Hai-Yan; Xu, Bo-Ping; Xu, Shang-Ling; Cui, Shuang

2013-03-01

Based on the investigation of sewer sediments in Xi Cheng district in Beijing, scour-release pollution load in one rainfall from sewer sediments was studied by monitoring the pollutants in the run-off of manhole's section. It was shown that the contribution of scour-release pollutants from sewer sediments to sewer outflow was obvious. The contribution rate of the sediments pollution load to runoff outflow in the 84 m pipeline in one rainfall (9 Jul., 2010) was as follows: TN 8.5%, TP 8.2%, COD 18.3%, SS 7.7%, respectively. And the pollutant contribution rate in the 295 m pipeline in another rainfall (4 Aug., 2010) was TN 23.12%, TP 60.01%, COD 33.78%, SS 31.89%. Therefore, it is important to control the pollution from sewer sediments for the improvement of water environment.

Application-Controlled Demand Paging for Out-of-Core Visualization

NASA Technical Reports Server (NTRS)

Cox, Michael; Ellsworth, David; Kutler, Paul (Technical Monitor)

1997-01-01

In the area of scientific visualization, input data sets are often very large. In visualization of Computational Fluid Dynamics (CFD) in particular, input data sets today can surpass 100 Gbytes, and are expected to scale with the ability of supercomputers to generate them. Some visualization tools already partition large data sets into segments, and load appropriate segments as they are needed. However, this does not remove the problem for two reasons: 1) there are data sets for which even the individual segments are too large for the largest graphics workstations, 2) many practitioners do not have access to workstations with the memory capacity required to load even a segment, especially since the state-of-the-art visualization tools tend to be developed by researchers with much more powerful machines. When the size of the data that must be accessed is larger than the size of memory, some form of virtual memory is simply required. This may be by segmentation, paging, or by paged segments. In this paper we demonstrate that complete reliance on operating system virtual memory for out-of-core visualization leads to poor performance. We then describe a paged segment system that we have implemented, and explore the principles of memory management that can be employed by the application for out-of-core visualization. We show that application control over some of these can significantly improve performance. We show that sparse traversal can be exploited by loading only those data actually required. We show also that application control over data loading can be exploited by 1) loading data from alternative storage format (in particular 3-dimensional data stored in sub-cubes), 2) controlling the page size. Both of these techniques effectively reduce the total memory required by visualization at run-time. We also describe experiments we have done on remote out-of-core visualization (when pages are read by demand from remote disk) whose results are promising.

Apparatus and Method for Cold Welding Thin Wafers to Hard Substrates

NASA Technical Reports Server (NTRS)

Oeftering, Richard C. (Inventor); Smith, Floyd A. (Inventor)

1996-01-01

An apparatus for coating and bonding parts in a vacuum includes a floating mount assembly holding one part and applying a bonding load to the parts. A pivoting mount assembly holds one part and is pivoted between a coating position and a bonding position. At least one coating source is provided for depositing a thin film of a metal onto a surface of each of the parts to improve the cold weld between the two parts. A restraining lever controls the application of the bonding load to the parts. The coating and bonding process occurs in a vacuum chamber with a single set-up.

Vent modification of large ribbon parachutes to enhance cluster performance

NASA Technical Reports Server (NTRS)

Kolega, D. J.; Woodis, W. R.; Reuter, J. D.

1986-01-01

Due to uneven load sharing and lagging inflation rates, the design of the Large Main Parachute (LMP) cluster, used to recover the Space Shuttle steel case Solid Rocket Boosters, had to be modified. The cause of the problem was excessive variation in effective porosity in the crown area of the LMP during first stage inflation. The design modification consisted of adding horizontal ribbons above the existing vent band to reduce the vent porosity and better control the position and attitude of the vent lines. Performance of modified LMP's since introduction indicates that the load sharing between the clustered chutes has been significantly improved.

Changes in psychosocial and physical working conditions and psychotropic medication in ageing public sector employees: a record-linkage follow-up study.

PubMed

Kouvonen, Anne; Mänty, Minna; Lallukka, Tea; Pietiläinen, Olli; Lahelma, Eero; Rahkonen, Ossi

2017-07-12

To investigate whether changes in psychosocial and physical working conditions are associated with subsequent psychotropic medication in ageing employees. Data were from the Helsinki Health Study, a cohort study of Finnish municipal employees, aged 40-60 years at phase 1 (2000-2002). Changes in psychosocial and physical working conditions were measured between phase 1 and phase 2 (2007). Survey data were longitudinally linked to data on prescribed, reimbursed psychotropic medication purchases (Anatomical Therapeutic Chemical) obtained from the registers of the Social Insurance Institution of Finland between the phase 2 survey and December 2013 (N=3587; 80% women). Outcomes were any psychotropic medication; antidepressants (N06A); anxiolytics (N05B); and sedatives and hypnotics (N05C). Cox regression analyses were performed. During the follow-up, 28% of the participants were prescribed psychotropic medication. Repeated exposures to low job control, high job demands and high physical work load were associated with an increased risk of subsequent antidepressant and anxiolytic medication. Increased and repeated exposure to high physical work load, increased job control and repeated high job demands were associated with subsequent sedative and hypnotic medication. Age and sex-adjusted HR varied from 1.18 to 1.66. Improvement in job control was associated with a lower risk of anxiolytic, but with a higher risk of sedatives and hypnotic medication. Decreased physical work load was associated with a lower risk of antidepressant and anxiolytic medications. Improvement in working conditions could lower the risk of mental ill-health indicated by psychotropic medication. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Silver-loaded seaweed-based cellulosic fiber improves epidermal skin physiology in atopic dermatitis: safety assessment, mode of action and controlled, randomized single-blinded exploratory in vivo study.

PubMed

Fluhr, Joachim W; Breternitz, Maria; Kowatzki, Doreen; Bauer, Andrea; Bossert, Joerg; Elsner, Peter; Hipler, Uta-Christina

2010-08-01

The epidermal part of the skin is the major interface between the internal body and the external environment. The skin has a specific physiology and is to different degrees adapted for protection against multiple exogenous stress factors. Clothing is the material with the longest and most intensive contact to human skin. It plays a critical role especially in inflammatory dermatoses or skin conditions with an increased susceptibility of bacterial and fungal infections like atopic dermatitis. Previously, we have shown a dose-dependent antibacterial and antifungal activity of silver-loaded seaweed-based cellulosic fibres. We studied the mode of action of silver-loaded seaweed-based cellulosic fiber and performed a broad safety assessment. The principal aim was to analyse the effects of wearing the textile on epidermal skin physiology in 37 patients with atopic dermatitis in a controlled, randomized single-blinded in vivo study. Furthermore, the sensitization potential was tested in a patch test in 111 panellists. We could demonstrate in vitro a dose-dependent scavenging of induced reactive oxygen species by silver-loaded seaweed-based cellulosic fibers. Safety assessment of these fibres showed no detectable release of silver ions. Furthermore, ex vivo assessment after 24 h application both in healthy volunteers and patients with atopic dermatitis by sequential tape stripping and subsequently raster electron microscopy and energy dispersive microanalysis analysis revealed no detectable amounts of silver in any of stratum corneum layers. Serum analysis of silver showed no detectable levels. The in vivo patch testing of 111 volunteers revealed no sensitization against different SeaCell Active (SeaCell GmbH, Rudolstadt, Germany) containing fabrics. The in vivo study on 37 patients with known atopic dermatitis and mild-to-moderate eczema on their arms were randomly assigned to either silver-loaded seaweed fibre T-shirts or to cotton T-shirts for 8 weeks. A significant reduction in Staphylococcus aureus colonization was detectable for the silver T-shirts compared with cotton T-shirts without any changes in non-pathogenic surface bacteria colonization. Furthermore, a more pronounced improvement in barrier function (transepidermal water loss) was observed in mildly involved eczema areas during the first 4 weeks of the study. Stratum corneum hydration and surface pH improved in both treatment groups over time. The tested silver-loaded seaweed fibre can be regarded as safe and seams to be suited for application in bio-active textiles in atopic dermatitis based on its positive in vivo activity.

Increased Resistance during Jump Exercise Does Not Enhance Cortical Bone Formation

PubMed Central

Boudreaux, Ramon D.; Swift, Joshua M.; Gasier, Heath G.; Wiggs, Michael P.; Hogan, Harry A.; Fluckey, James D.; Bloomfield, Susan A.

2014-01-01

PURPOSE This study sought to elucidate the effects of a low- and high-load jump resistance exercise (RE) training protocol on cortical bone of the tibia and femur mid-diaphyses. METHODS Sprague-Dawley rats (male, 6-mos-old) were randomly assigned to high-load RE (HRE; n = 16), low-load RE (LRE; n = 15) or cage control (CC; n = 11) groups. Animals in the HRE and LRE groups performed 15 sessions of jump RE for 5 weeks. Load in the HRE group was progressively increased from 80g added to a weighted vest (50 repetitions) to 410g (16 repetitions). The LRE rats completed the same protocol as the HRE group (same number of repetitions) with only a 30g vest applied. RESULTS Low- and high-load jump RE resulted in 6–11% higher cortical bone mineral content (BMC) and cortical bone area compared to controls as determined by in vivo pQCT measurements. In the femur, however, only LRE demonstrated improvements in cortical volumetric bone mineral density (vBMD; +11%) and cross-sectional moment of inertia (CSMI; +20%) versus CC group. Three-point bending to failure revealed a marked increase in tibial max force (25–29%), stiffness (19–22%), and energy to max force (35–55%), and a reduction in elastic modulus (−11–14%) in both LRE and HRE compared to controls. Dynamic histomorphometry assessed at the tibia mid-diaphysis determined that both LRE and HRE resulted in 20–30% higher periosteal mineralizing surface versus CC group. Mineral apposition rate (MAR) and bone formation rate (BFR) were significantly greater in LRE animals (27%, 39%) than in the HRE group. CONCLUSION These data demonstrate that jump training with minimal loading is equally, and sometimes more, effective at augmenting cortical bone integrity compared to overload training in skeletally mature rats. PMID:24743108

14 CFR 23.415 - Ground gust conditions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... and System Loads § 23.415 Ground gust conditions. (a) The control system must be investigated as... control system for ground gust loads is not required by paragraph (a)(2) of this section, but the applicant elects to design a part of the control system of these loads, these loads need only be carried...

Wireless power charging using point of load controlled high frequency power converters

DOEpatents

Miller, John M.; Campbell, Steven L.; Chambon, Paul H.; Seiber, Larry E.; White, Clifford P.

2015-10-13

An apparatus for wirelessly charging a battery of an electric vehicle is provided with a point of load control. The apparatus includes a base unit for generating a direct current (DC) voltage. The base unit is regulated by a power level controller. One or more point of load converters can be connected to the base unit by a conductor, with each point of load converter comprising a control signal generator that transmits a signal to the power level controller. The output power level of the DC voltage provided by the base unit is controlled by power level controller such that the power level is sufficient to power all active load converters when commanded to do so by any of the active controllers, without generating excessive power that may be otherwise wasted.

Excellent photocatalytic hydrogen production over CdS nanorods via using noble metal-free copper molybdenum sulfide (Cu2MoS4) nanosheets as co-catalysts

NASA Astrophysics Data System (ADS)

Hong, Sangyeob; Kumar, D. Praveen; Reddy, D. Amaranatha; Choi, Jiha; Kim, Tae Kyu

2017-02-01

Charge carrier recombination and durability issues are major problems in photocatalytic hydrogen (H2) evolution processes. Thus, there is a very important necessitate to extend an efficient photocatalyst to control charge-carrier dynamics in the photocatalytic system. We have developed copper molybdenum sulfide (Cu2MoS4) nanosheets as co-catalysts with CdS nanorods for controlling charge carriers without recombination for use in photocatalytic H2 evolution under simulated solar light irradiation. Effective control and utilization of charge carriers are possible by loading Cu2MoS4 nanosheets onto the CdS nanorods. The loading compensates for the restrictions of CdS, and stimulated synergistic effects, such as efficient photoexcited charge separation, lead to an improvement in photostability because of the layered structure of the Cu2MoS4nanosheets. These layered Cu2MoS4 nanosheets have emerged as novel and active replacements for precious noble metal co-catalysts in photocatalytic H2 production by water splitting. We have obtained superior H2 production rates by using Cu2MoS4 loaded CdS nanorods. The physicochemical properties of the composites are analyzed by diverse characterization techniques.

Numerical optimization of composite hip endoprostheses under different loading conditions

NASA Technical Reports Server (NTRS)

Blake, T. A.; Davy, D. T.; Saravanos, D. A.; Hopkins, D. A.

1992-01-01

The optimization of composite hip implants was investigated. Emphasis was placed on the effect of shape and material tailoring of the implant to improve the implant-bone interaction. A variety of loading conditions were investigated to better understand the relationship between loading and optimization outcome. Comparisons of the initial and optimal models with more complex 3D finite element models were performed. The results indicate that design improvements made using this method result in similar improvements in the 3D models. Although the optimization outcomes were significantly affected by the choice of loading conditions, certain trends were observed that were independent of the applied loading.

A Hybrid Converter for Improving Light Load Efficiency

NASA Astrophysics Data System (ADS)

Takahashi, Masaya; Nishijima, Kimihiro; Nagao, Michihiko; Sato, Terukazu; Nabeshima, Takashi

In order to reduce power consumption of electronic equipment in stand-by mode, idle-mode and sleep-mode, a simple efficiency improvement technique for switching regulator in light load region is proposed. In this technique, under the light load, the small switching elements in a MOSFET driver circuit are used instead of the switching elements in a main regulator circuit to reduce driving losses. Of course, under the load heavier than light load, the MOSFET driver drives the switching elements in the main regulator circuit. The efficiency of a 2.5V/5A prototype buck converter is improved from 47.1% to 72.7% by using the proposed technique.

Indirect adaptive fuzzy wavelet neural network with self- recurrent consequent part for AC servo system.

PubMed

Hou, Runmin; Wang, Li; Gao, Qiang; Hou, Yuanglong; Wang, Chao

2017-09-01

This paper proposes a novel indirect adaptive fuzzy wavelet neural network (IAFWNN) to control the nonlinearity, wide variations in loads, time-variation and uncertain disturbance of the ac servo system. In the proposed approach, the self-recurrent wavelet neural network (SRWNN) is employed to construct an adaptive self-recurrent consequent part for each fuzzy rule of TSK fuzzy model. For the IAFWNN controller, the online learning algorithm is based on back propagation (BP) algorithm. Moreover, an improved particle swarm optimization (IPSO) is used to adapt the learning rate. The aid of an adaptive SRWNN identifier offers the real-time gradient information to the adaptive fuzzy wavelet neural controller to overcome the impact of parameter variations, load disturbances and other uncertainties effectively, and has a good dynamic. The asymptotical stability of the system is guaranteed by using the Lyapunov method. The result of the simulation and the prototype test prove that the proposed are effective and suitable. Copyright © 2017. Published by Elsevier Ltd.

Testing of an Amine-Based Pressure-Swing System for Carbon Dioxide and Humidity Control

NASA Technical Reports Server (NTRS)

Lin, Amy; Smith, Frederick; Sweterlitsch, Jeffrey; Graf, John; Nalette, Tim; Papale, William; Campbell, Melissa; Lu, Sao-Dung

2007-01-01

In a crewed spacecraft environment, atmospheric carbon dioxide (CO2) and moisture control is crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO2 and water vapor sorbent, SA9T, that is well-suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are all controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft. However, more data was needed on the operational characteristics of the package in a simulated spacecraft environment. A unit was therefore tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the last third of 2006. Tests were run at a variety of cabin temperatures and with a range of operating conditions varying cycle time, vacuum pressure, air flow rate, and crew activity levels. Results of this testing are presented and potential flight operational strategies discussed.

Isolated Power Generation System Using Permanent Magnet Synchronous Generator with Improved Power Quality

NASA Astrophysics Data System (ADS)

Arya, Sabha Raj; Patel, Ashish; Giri, Ashutosh

2018-06-01

This paper deals wind energy based power generation system using Permanent Magnet Synchronous Generator (PMSG). It is controlled using advanced enhanced phase-lock loop for power quality features using distribution static compensator to eliminate the harmonics and to provide KVAR compensation as well as load balancing. It also manages rated potential at the point of common interface under linear and non-linear loads. In order to have better efficiency and reliable operation of PMSG driven by wind turbine, it is necessary to analyze the governing equation of wind based turbine and PMSG under fixed and variable wind speed. For handling power quality problems, power electronics based shunt connected custom power device is used in three wire system. The simulations in MATLAB/Simulink environment have been carried out in order to demonstrate this model and control approach used for the power quality enhancement. The performance results show the adequate performance of PMSG based power generation system and control algorithm.

Power quality improvement of a stand-alone power system subjected to various disturbances

NASA Astrophysics Data System (ADS)

Lone, Shameem Ahmad; Mufti, Mairaj Ud-Din

In wind-diesel stand-alone power systems, the disturbances like random nature of wind power, turbulent wind, sudden changes in load demand and the wind park disconnection effect continuously the system voltage and frequency. The satisfactory operation of such a system is not an easy task and the control design has to take in to account all these subtleties. For maintaining the power quality, generally, a short-term energy storage device is used. In this paper, the performance of a wind-diesel system associated with a superconducting magnetic energy storage (SMES) system is studied. The effect of installing SMES at wind park bus/load bus, on the system performance is investigated. To control the exchange of real and reactive powers between the SMES unit and the wind-diesel system, a control strategy based on fuzzy logic is proposed. The dynamic models of the hybrid power system for most common scenarios are developed and the results presented.

Isolated Power Generation System Using Permanent Magnet Synchronous Generator with Improved Power Quality

NASA Astrophysics Data System (ADS)

Arya, Sabha Raj; Patel, Ashish; Giri, Ashutosh

2018-03-01

This paper deals wind energy based power generation system using Permanent Magnet Synchronous Generator (PMSG). It is controlled using advanced enhanced phase-lock loop for power quality features using distribution static compensator to eliminate the harmonics and to provide KVAR compensation as well as load balancing. It also manages rated potential at the point of common interface under linear and non-linear loads. In order to have better efficiency and reliable operation of PMSG driven by wind turbine, it is necessary to analyze the governing equation of wind based turbine and PMSG under fixed and variable wind speed. For handling power quality problems, power electronics based shunt connected custom power device is used in three wire system. The simulations in MATLAB/Simulink environment have been carried out in order to demonstrate this model and control approach used for the power quality enhancement. The performance results show the adequate performance of PMSG based power generation system and control algorithm.

Encapsulation of an adamantane-doxorubicin prodrug in pH-responsive polysaccharide capsules for controlled release.

PubMed

Luo, Guo-Feng; Xu, Xiao-Ding; Zhang, Jing; Yang, Juan; Gong, Yu-Hui; Lei, Qi; Jia, Hui-Zhen; Li, Cao; Zhuo, Ren-Xi; Zhang, Xian-Zheng

2012-10-24

Supramolecular microcapsules (SMCs) with the drug-loaded wall layers for pH-controlled drug delivery were designed and prepared. By using layer-by-layer (LbL) technique, the SMCs were constructed based on the self-assembly between polyaldenhyde dextran-graft-adamantane (PAD-g-AD) and carboxymethyl dextran-graft-β-CD (CMD-g-β-CD) on CaCO(3) particles via host-guest interaction. Simultaneously, adamantine-modified doxorubicin (AD-Dox) was also loaded on the LbL wall via host-guest interaction. The in vitro drug release study was carried out at different pHs. Because the AD groups were linked with PAD (PAD-g-AD) or Dox (AD-Dox) by pH-cleavable hydrazone bonds, AD moieties can be removed under the weak acidic condition, leading to destruction of SMCs and release of Dox. The pH-controlled drug release can enhance the uptake by tumor cells and thus achieve improved cancer therapy efficiency.