Maximum Allowable Dynamic Load of Mobile Manipulators with Stability Consideration
Heidary H. R.
2015-09-01
Full Text Available High payload to mass ratio is one of the advantages of mobile robot manipulators. In this paper, a general formula for finding the maximum allowable dynamic load (MADL of wheeled mobile robot is presented. Mobile manipulators operating in field environments will be required to manipulate large loads, and to perform such tasks on uneven terrain, which may cause the system to reach dangerous tip-over instability. Therefore, the method is expanded for finding the MADL of mobile manipulators with stability consideration. Moment-Height Stability (MHS criterion is used as an index for the system stability. Full dynamic model of wheeled mobile base and mounted manipulator is considered with respect to the dynamic of non-holonomic constraint. Then, a method for determination of the maximum allowable loads is described, subject to actuator constraints and by imposing the stability limitation as a new constraint. The actuator torque constraint is applied by using a speed-torque characteristics curve of a typical DC motor. In order to verify the effectiveness of the presented algorithm, several simulation studies considering a two-link planar manipulator, mounted on a mobile base are presented and the results are discussed.
Maximum holding endurance time: Effects of load and load's center of gravity height.
Lee, Tzu-Hsien
2015-01-01
Manual holding task is a potential risk to the development of musculoskeletal injuries since it is prone to induce localized muscle fatigue. Maximum holding endurance time is a significant parameter for the design of manual holding task. This study aimed to examine the effects of load and load's COG height on maximum holding endurance time. Fifteen young and healthy males were recruited as participants. A factorial design was used to examine the effects of load and load's COG height on maximum holding endurance time. Four levels of load (15% , 30% , 45% and 60% of the participant's maximum holding capacity) and two levels of load's COG height in box (0 cm and 40 cm high from the handle position) were examined. Maximum holding endurance time decreased with increasing load and/or increasing load's COG height. The effect of load's COG height on maximum holding endurance time decreased with increasing load. Load, load's COG height, and the interaction of load and load's COG height significantly affected maximum holding endurance time. Practitioners should realize the effects of load, load's COG height, and the interaction of load and load's COG height on maximum holding endurance time when setting the working conditions of holding tasks.
Water Quality Assessment and Total Maximum Daily Loads Information (ATTAINS)
U.S. Environmental Protection Agency — The Water Quality Assessment TMDL Tracking And Implementation System (ATTAINS) stores and tracks state water quality assessment decisions, Total Maximum Daily Loads...
Environmental Monitoring, Water Quality - Total Maximum Daily Load (TMDL)
NSGIC GIS Inventory (aka Ramona) — The Clean Water Act Section 303(d) establishes the Total Maximum Daily Load (TMDL) program. The purpose of the TMDL program is to identify sources of pollution and...
Environmental Monitoring, Water Quality - Total Maximum Daily Load (TMDL)
NSGIC Education | GIS Inventory — The Clean Water Act Section 303(d) establishes the Total Maximum Daily Load (TMDL) program. The purpose of the TMDL program is to identify sources of pollution and...
Fischer, Andreas; Aagaard Madsen, Helge
2014-01-01
The maximum fatigue load reduction potential when using trailing edge flaps on mega-watt wind turbines was explored. For this purpose an ideal feed forward control algorithm using the relative velocity and angle of attack at the blade to control the loads was implemented. The algorithm was applie...... the blade load location was investigated. When the algorithm was applied to measured time series a load reduction of 23% was achieved which is still promissing, but significantly lower than the value achieved in computations....
LITERATURE REVIEW ON MAXIMUM LOADING OF RADIONUCLIDES ON CRYSTALLINE SILICOTITANATE
Adu-Wusu, K.; Pennebaker, F.
2010-10-13
Plans are underway to use small column ion exchange (SCIX) units installed in high-level waste tanks to remove Cs-137 from highly alkaline salt solutions at Savannah River Site. The ion exchange material slated for the SCIX project is engineered or granular crystalline silicotitanate (CST). Information on the maximum loading of radionuclides on CST is needed by Savannah River Remediation for safety evaluations. A literature review has been conducted that culminated in the estimation of the maximum loading of all but one of the radionuclides of interest (Cs-137, Sr-90, Ba-137m, Pu-238, Pu-239, Pu-240, Pu-241, Am-241, and Cm-244). No data was found for Cm-244.
Effects of loading on maximum vertical jumps: selective effects of weight and inertia
Leontijevic, Bojan; Pazin, Nemanja; Bozic, Predrag R.; Kukolj, Milos; Ugarkovic, Dusan; Jaric, Slobodan
2011-01-01
A novel loading method was applied to explore selective effects of externally added weight (W), weight and inertia (W+I), and inertia (I) on maximum counter-movement jumps (CMJ) performed with arm swing. Externally applied extended rubber bands and/or loaded vest added W, W+I, and I corresponding to 10–40% of subjects' body mass. As expected, an increase in magnitude of all types of load was associated with an increase in ground reaction forces (GRF), as well as with a decrease in both the ju...
Effects of loading on maximum vertical jumps: Selective effects of weight and inertia.
Leontijevic, Bojan; Pazin, Nemanja; Bozic, Predrag R; Kukolj, Milos; Ugarkovic, Dusan; Jaric, Slobodan
2012-04-01
A novel loading method was applied to explore selective effects of externally added weight (W), weight and inertia (W+I), and inertia (I) on maximum counter-movement jumps (CMJ) performed with arm swing. Externally applied extended rubber bands and/or loaded vest added W, W+I, and I corresponding to 10-40% of subjects' body mass. As expected, an increase in magnitude of all types of load was associated with an increase in ground reaction forces (GRF), as well as with a decrease in both the jumping performance and power output. However, of more importance could be that discernible differences among the effects of W, W+I, and I were recorded despite a relatively narrow loading range. In particular, an increase in W was associated with the minimal changes in movement kinematic pattern and smallest reduction of jumping performance, while also allowing for the highest power output. Conversely, W+I was associated with the highest ground reaction forces. Finally, the lowest maxima of GRF and power were associated with I. Although further research is apparently needed, the obtained finding could be of potential importance not only for understanding fundamental properties of the neuromuscular system, but also for optimization of loading in standard athletic training and rehabilitation procedures.
Constrained maximum likelihood modal parameter identification applied to structural dynamics
El-Kafafy, Mahmoud; Peeters, Bart; Guillaume, Patrick; De Troyer, Tim
2016-05-01
A new modal parameter estimation method to directly establish modal models of structural dynamic systems satisfying two physically motivated constraints will be presented. The constraints imposed in the identified modal model are the reciprocity of the frequency response functions (FRFs) and the estimation of normal (real) modes. The motivation behind the first constraint (i.e. reciprocity) comes from the fact that modal analysis theory shows that the FRF matrix and therefore the residue matrices are symmetric for non-gyroscopic, non-circulatory, and passive mechanical systems. In other words, such types of systems are expected to obey Maxwell-Betti's reciprocity principle. The second constraint (i.e. real mode shapes) is motivated by the fact that analytical models of structures are assumed to either be undamped or proportional damped. Therefore, normal (real) modes are needed for comparison with these analytical models. The work done in this paper is a further development of a recently introduced modal parameter identification method called ML-MM that enables us to establish modal model that satisfies such motivated constraints. The proposed constrained ML-MM method is applied to two real experimental datasets measured on fully trimmed cars. This type of data is still considered as a significant challenge in modal analysis. The results clearly demonstrate the applicability of the method to real structures with significant non-proportional damping and high modal densities.
Maximum Likelihood Estimation of Time-Varying Loadings in High-Dimensional Factor Models
Mikkelsen, Jakob Guldbæk; Hillebrand, Eric; Urga, Giovanni
In this paper, we develop a maximum likelihood estimator of time-varying loadings in high-dimensional factor models. We specify the loadings to evolve as stationary vector autoregressions (VAR) and show that consistent estimates of the loadings parameters can be obtained by a two-step maximum...... likelihood estimation procedure. In the first step, principal components are extracted from the data to form factor estimates. In the second step, the parameters of the loadings VARs are estimated as a set of univariate regression models with time-varying coefficients. We document the finite...
Effects of loading and size on maximum power output and gait characteristics in geckos.
Irschick, Duncan J; Vanhooydonck, Bieke; Herrel, Anthony; Andronescu, Anemone
2003-11-01
Stride length, stride frequency and power output are all factors influencing locomotor performance. Here, we first test whether mass-specific power output limits climbing performance in two species of geckos (Hemidactylus garnoti and Gekko gecko) by adding external loads to their bodies. We then test whether body size has a negative effect on mass-specific power output. Finally, we test whether loading affects kinematics in both gecko species. Lizards were induced to run vertically on a smooth wooden surface with loads of 0-200% of body mass (BM) in H. garnoti and 0-100% BM in G. gecko. For each stride, we calculated angular and linear kinematics (e.g. trunk angle, stride length), performance (maximum speed) and mean mass-specific power output per stride. The addition of increasingly large loads caused an initial increase in maximum mass-specific power output in both species, but for H. garnoti, mass-specific power output remained constant at higher loads (150% and 200% BM), even though maximum velocity declined. This result, in combination with the fact that stride frequency showed no evidence of leveling off as speed increased in either species, suggests that power limits maximum speed. In addition, the large gecko (G. gecko) produced significantly less power than the smaller H. garnoti, despite the fact that both species ran at similar speeds. This difference disappeared, however, when we recalculated power output based on higher maximum speeds for unloaded G. gecko moving vertically obtained by other researchers. Finally, the addition of external loads did not affect speed modulation in either species: both G. gecko and H. garnoti increase speed primarily by increasing stride frequency, regardless of loading condition. For a given speed, both species take shorter but more strides with heavier loads, but for a given load, G. gecko attains similar speeds to H. garnoti by taking longer but fewer strides.
A Load Balancing Algorithm Based on Maximum Entropy Methods in Homogeneous Clusters
Long Chen
2014-10-01
Full Text Available In order to solve the problems of ill-balanced task allocation, long response time, low throughput rate and poor performance when the cluster system is assigning tasks, we introduce the concept of entropy in thermodynamics into load balancing algorithms. This paper proposes a new load balancing algorithm for homogeneous clusters based on the Maximum Entropy Method (MEM. By calculating the entropy of the system and using the maximum entropy principle to ensure that each scheduling and migration is performed following the increasing tendency of the entropy, the system can achieve the load balancing status as soon as possible, shorten the task execution time and enable high performance. The result of simulation experiments show that this algorithm is more advanced when it comes to the time and extent of the load balance of the homogeneous cluster system compared with traditional algorithms. It also provides novel thoughts of solutions for the load balancing problem of the homogeneous cluster system.
Viral load: Roche applies for marketing approval for ultrasensitive test.
1998-08-07
Roche Molecular Systems has applied for FDA permission to market a more sensitive viral load test. The Amplicor HIV-1 Monitor UltraSensitive Method tests viral load as low as 50 copies; current tests are only accurate to 400 copies. There is a widespread consensus among physicians that testing below 400 copies would be a valuable treatment tool.
DEPENDENCY OF OSTEOGENIC EFFECTS ON CHARACTERISTICS OF MECHANICAL LOAD APPLIED TO OSSEOUS STRUCTURES
A. S. Avrunin
2016-01-01
Full Text Available Purpose of the study: to evaluate osteogenic rate of various characteristics of mechanical loading based on the authors’ data as well as literature analysis.Literature analysis proved that clinical outcome of physical training can be achieved not only by increasing the mechanical load but also by altering number of load iterations, rate of load acceleration, frequency of cyclic load, rest interval, distribution of load across the skeleton. Presented data provides a reasonable basis to apply alterations of all above-mentioned load characteristics to obtain clinical effect and customize every single baseline exercise plan to gain a maximum treatment and preventive effect in individuals with high risk of osteoporotic fractures.
A New Experimental Technique for Applying Impulse Tension Loading
Fan, Z. S.; Yu, H. P.; Su, H; Zhang, X.; Li, C. F.
2016-01-01
This paper deals with a new experimental technique for applying impulse tension loads. Briefly, the technique is based on the use of pulsed-magnetic-driven tension loading. Electromagnetic forming (EMF) can be quite effective in increasing the forming limits of metal sheets, such as aluminium and magnesium alloys. Yet, why the forming limit is increased is still an open question. One reason for this is the difficulty to let forming proceed on a certain influence monotonically: ...
Investigation of Maximum Blade Loading Capability of Lift-Offset Rotors
Yeo, Hyeonsoo; Johnson, Wayne
2013-01-01
Maximum blade loading capability of a coaxial, lift-offset rotor is investigated using a rotorcraft configuration designed in the context of short-haul, medium-size civil and military missions. The aircraft was sized for a 6600-lb payload and a range of 300 nm. The rotor planform and twist were optimized for hover and cruise performance. For the present rotor performance calculations, the collective pitch angle is progressively increased up to and through stall with the shaft angle set to zero. The effects of lift offset on rotor lift, power, controls, and blade airloads and structural loads are examined. The maximum lift capability of the coaxial rotor increases as lift offset increases and extends well beyond the McHugh lift boundary as the lift potential of the advancing blades are fully realized. A parametric study is conducted to examine the differences between the present coaxial rotor and the McHugh rotor in terms of maximum lift capabilities and to identify important design parameters that define the maximum lift capability of the rotor. The effects of lift offset on rotor blade airloads and structural loads are also investigated. Flap bending moment increases substantially as lift offset increases to carry the hub roll moment even at low collective values. The magnitude of flap bending moment is dictated by the lift-offset value (hub roll moment) but is less sensitive to collective and speed.
Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure
Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Foglia, Aligi
2015-01-01
to apply an overburden pressure to the soil. As a result of that, the traditional uncertainties related to low effective stresses for small-scale tests have been avoided. A normalisation criterion for laterally loaded piles has been proposed based on dimensional analysis. The test results using the novel...
Exercise, muscle, and the applied load-bone strength balance.
Giangregorio, L; El-Kotob, R
2017-01-01
A fracture occurs when the applied load is greater than the bone can withstand. Clinical practice guidelines for the management of osteoporosis include recommendations for exercise; one of the few therapies where the proposed anti-fracture mechanisms that include effects on both bone strength and applied loads, where applied loads can come in the form of a fall, externally applied loads, body weight, or muscle forces. The aim of this review is to provide an overview of the clinical evidence pertaining to the potential efficacy of exercise for preventing fractures in older adults, including its direct effects on outcomes along the causal pathway to fractures (e.g., falls, posture, bone strength) and the indirect effects on muscle or the muscle-bone relationship. The evidence is examined as it pertains to application in clinical practice. Considerations for future research are discussed, such as the need for trials in individuals with low bone mass or students that evaluate whether changes in muscle mediate changes in bone. Future trials should also consider adequacy of calorie or protein intake, the confounding effect of exercise-induced weight loss, or the most appropriate therapeutic goal (e.g., strength, weight bearing, or hypertrophy) and outcome measures (e.g., fracture, disability, cost-effectiveness).
Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure
Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Foglia, Aligi
2015-01-01
Small-scale tests have been conducted to investigate the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank such that it was possible...... to apply an overburden pressure to the soil. As a result of that, the traditional uncertainties related to low effective stresses for small-scale tests have been avoided. A normalisation criterion for laterally loaded piles has been proposed based on dimensional analysis. The test results using the novel...
Testing of Laterally Loaded Rigid Piles with Applied Overburden Pressure
Sørensen, Søren Peder Hyldal; Foglia, Aligi; Ibsen, Lars Bo
2012-01-01
Small-scale tests have been conducted for the purpose of investigating the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank such that......Small-scale tests have been conducted for the purpose of investigating the quasi-static behaviour of laterally loaded, non-slender piles installed in cohesionless soil. For that purpose, a new and innovative test setup has been developed. The tests have been conducted in a pressure tank...... such that it was possible to apply an overburden pressure to the soil. Hereby, the traditional uncertainties related to low effective stresses for small-scale tests has been avoided. A scaling law for laterally loaded piles has been proposed based on dimensional analysis. The novel testing method has been validated against...
Applying rough sets in word segmentation disambiguation based on maximum entropy model
无
2006-01-01
To solve the complicated feature extraction and long distance dependency problem in Word Segmentation Disambiguation ( WSD), this paper proposes to apply rough sets in WSD based on the Maximum Entropy model. Firstly, rough set theory is applied to extract the complicated features and long distance features, even from noise or inconsistent corpus. Secondly, these features are added into the Maximum Entropy model, and consequently, the feature weights can be assigned according to the performance of the whole disambiguation model. Finally, the semantic lexicon is adopted to build class-based rough set features to overcome data sparseness. The experiment indicated that our method performed better than previous models, which got top rank in WSD in 863 Evaluation in 2003. This system ranked first and second respectively in MSR and PKU open test in the Second International Chinese Word Segmentation Bakeoff held in 2005.
Maximum organic loading rate for the single-stage wet anaerobic digestion of food waste.
Nagao, Norio; Tajima, Nobuyuki; Kawai, Minako; Niwa, Chiaki; Kurosawa, Norio; Matsuyama, Tatsushi; Yusoff, Fatimah Md; Toda, Tatsuki
2012-08-01
Anaerobic digestion of food waste was conducted at high OLR from 3.7 to 12.9 kg-VS m(-3) day(-1) for 225 days. Periods without organic loading were arranged between the each loading period. Stable operation at an OLR of 9.2 kg-VS (15.0 kg-COD) m(-3) day(-1) was achieved with a high VS reduction (91.8%) and high methane yield (455 mL g-VS-1). The cell density increased in the periods without organic loading, and reached to 10.9×10(10) cells mL(-1) on day 187, which was around 15 times higher than that of the seed sludge. There was a significant correlation between OLR and saturated TSS in the sludge (y=17.3e(0.1679×), r(2)=0.996, P<0.05). A theoretical maximum OLR of 10.5 kg-VS (17.0 kg-COD) m(-3) day(-1) was obtained for mesophilic single-stage wet anaerobic digestion that is able to maintain a stable operation with high methane yield and VS reduction.
Zhang, H X
2008-01-01
An innovative approach for total maximum daily load (TMDL) allocation and implementation is the watershed-based pollutant trading. Given the inherent scientific uncertainty for the tradeoffs between point and nonpoint sources, setting of trading ratios can be a contentious issue and was already listed as an obstacle by several pollutant trading programs. One of the fundamental reasons that a trading ratio is often set higher (e.g. greater than 2) is to allow for uncertainty in the level of control needed to attain water quality standards, and to provide a buffer in case traded reductions are less effective than expected. However, most of the available studies did not provide an approach to explicitly address the determination of trading ratio. Uncertainty analysis has rarely been linked to determination of trading ratio.This paper presents a practical methodology in estimating "equivalent trading ratio (ETR)" and links uncertainty analysis with trading ratio determination from TMDL allocation process. Determination of ETR can provide a preliminary evaluation of "tradeoffs" between various combination of point and nonpoint source control strategies on ambient water quality improvement. A greater portion of NPS load reduction in overall TMDL load reduction generally correlates with greater uncertainty and thus requires greater trading ratio. The rigorous quantification of trading ratio will enhance the scientific basis and thus public perception for more informed decision in overall watershed-based pollutant trading program.
An ultrasonic guided wave method to estimate applied biaxial loads
Shi, Fan; Michaels, Jennifer E.; Lee, Sang Jun
2012-05-01
Guided waves propagating in a homogeneous plate are known to be sensitive to both temperature changes and applied stress variations. Here we consider the inverse problem of recovering homogeneous biaxial stresses from measured changes in phase velocity at multiple propagation directions using a single mode at a specific frequency. Although there is no closed form solution relating phase velocity changes to applied stresses, prior results indicate that phase velocity changes can be closely approximated by a sinusoidal function with respect to angle of propagation. Here it is shown that all sinusoidal coefficients can be estimated from a single uniaxial loading experiment. The general biaxial inverse problem can thus be solved by fitting an appropriate sinusoid to measured phase velocity changes versus propagation angle, and relating the coefficients to the unknown stresses. The phase velocity data are obtained from direct arrivals between guided wave transducers whose direct paths of propagation are oriented at different angles. This method is applied and verified using sparse array data recorded during a fatigue test. The additional complication of the resulting fatigue cracks interfering with some of the direct arrivals is addressed via proper selection of transducer pairs. Results show that applied stresses can be successfully recovered from the measured changes in guided wave signals.
Faggian, Silvia
2007-01-01
The paper concerns the study of the Pontryagin Maximum Principle for an infinite dimensional and infinite horizon boundary control problem for linear partial differential equations. The optimal control model has already been studied both in finite and infinite horizon with Dynamic Programming methods in a series of papers by the same author, or by Faggian and Gozzi. Necessary and sufficient optimality conditions for open loop controls are established. Moreover the co-state variable is shown to coincide with the spatial gradient of the value function evaluated along the trajectory of the system, creating a parallel between Maximum Principle and Dynamic Programming. The abstract model applies, as recalled in one of the first sections, to optimal investment with vintage capital.
Xuan Guo
2016-01-01
Full Text Available The theoretical formula of the maximum internal forces for circular tunnel lining structure under impact loads of the underground is deduced in this paper. The internal force calculation formula under different equivalent forms of impact pseudostatic loads is obtained. Furthermore, by comparing the theoretical solution with the measured data of the top blasting model test of circular formula under different equivalent forms of impact pseudostatic loads are obtained. Furthermore, by comparing the theoretical solution with the measured data of the top blasting model test of circular tunnel, it is found that the proposed theoretical results accord with the experimental values well. The corresponding equivalent impact pseudostatic triangular load is the most realistic pattern of all test equivalent forms. The equivalent impact pseudostatic load model and maximum solution of the internal force for tunnel lining structure are partially verified.
Technical evaluation of a total maximum daily load model for Upper Klamath and Agency Lakes, Oregon
Wood, Tamara M.; Wherry, Susan A.; Carter, James L.; Kuwabara, James S.; Simon, Nancy S.; Rounds, Stewart A.
2013-01-01
We reviewed a mass balance model developed in 2001 that guided establishment of the phosphorus total maximum daily load (TMDL) for Upper Klamath and Agency Lakes, Oregon. The purpose of the review was to evaluate the strengths and weaknesses of the model and to determine whether improvements could be made using information derived from studies since the model was first developed. The new data have contributed to the understanding of processes in the lakes, particularly internal loading of phosphorus from sediment, and include measurements of diffusive fluxes of phosphorus from the bottom sediments, groundwater advection, desorption from iron oxides at high pH in a laboratory setting, and estimates of fluxes of phosphorus bound to iron and aluminum oxides. None of these processes in isolation, however, is large enough to account for the episodically high values of whole-lake internal loading calculated from a mass balance, which can range from 10 to 20 milligrams per square meter per day for short periods. The possible role of benthic invertebrates in lake sediments in the internal loading of phosphorus in the lake has become apparent since the development of the TMDL model. Benthic invertebrates can increase diffusive fluxes several-fold through bioturbation and biodiffusion, and, if the invertebrates are bottom feeders, they can recycle phosphorus to the water column through metabolic excretion. These organisms have high densities (1,822–62,178 individuals per square meter) in Upper Klamath Lake. Conversion of the mean density of tubificid worms (Oligochaeta) and chironomid midges (Diptera), two of the dominant taxa, to an areal flux rate based on laboratory measurements of metabolic excretion of two abundant species suggested that excretion by benthic invertebrates is at least as important as any of the other identified processes for internal loading to the water column. Data from sediment cores collected around Upper Klamath Lake since the development of the
Economic total maximum daily load for watershed-based pollutant trading.
Zaidi, A Z; deMonsabert, S M
2015-04-01
Water quality trading (WQT) is supported by the US Environmental Protection Agency (USEPA) under the framework of its total maximum daily load (TMDL) program. An innovative approach is presented in this paper that proposes post-TMDL trade by calculating pollutant rights for each pollutant source within a watershed. Several water quality trading programs are currently operating in the USA with an objective to achieve overall pollutant reduction impacts that are equivalent or better than TMDL scenarios. These programs use trading ratios for establishing water quality equivalence among pollutant reductions. The inbuilt uncertainty in modeling the effects of pollutants in a watershed from both the point and nonpoint sources on receiving waterbodies makes WQT very difficult. A higher trading ratio carries with it increased mitigation costs, but cannot ensure the attainment of the required water quality with certainty. The selection of an applicable trading ratio, therefore, is not a simple process. The proposed approach uses an Economic TMDL optimization model that determines an economic pollutant reduction scenario that can be compared with actual TMDL allocations to calculate selling/purchasing rights for each contributing source. The methodology is presented using the established TMDLs for the bacteria (fecal coliform) impaired Muddy Creek subwatershed WAR1 in Rockingham County, Virginia, USA. Case study results show that an environmentally and economically superior trading scenario can be realized by using Economic TMDL model or any similar model that considers the cost of TMDL allocations.
Testing of Axially Loaded Bucket Foundation with Applied Overburden Pressure
Vaitkunaite, Evelina; Ibsen, Lars Bo; Nielsen, Benjaminn Nordahl
This report analyses laboratory testing data performed with a bucket foundation model subjected to axial loading. The examinations were conducted at the Geotechnical laboratory of Aalborg University. The report aims at showing and discussing the results of the static and cyclic axial loading tests...
Gronewold, A. D.; Alameddine, I.; Anderson, R.; Wolpert, R.; Reckhow, K.
2008-12-01
The United States Environmental Protection Agency (USEPA) total maximum daily load (TMDL) program requires that individual states assess the condition of surface waters and identify those which fail to meet ambient water quality standards. Waters failing to meet those standards must have a TMDL assessment conducted to determine the maximum allowable pollutant load which can enter the water without violating water quality standards. While most of the nearly 30,000 TMDL assessments completed since 1995 use mechanistic or empirical water quality models to forecast water quality conditions under alternative pollutant loading reduction scenarios, few, if any, also simulate water quality conditions under alternative climate change scenarios. As a result, model-based loading reduction requirements (which serve as the cornerstone for implementing water resource management plans, and initiating environmental management infrastructure projects), believed to improve water quality in impaired waters and reinstate their designated use, may misrepresent the actual required reduction when future climate change scenarios are considered. For example, recent research indicates a potential long term future increase in both the number of days between, and the intensity of, individual precipitation events. In coastal terrestrial and aquatic ecosystems, such climate conditions could lead to an increased accumulation of pollutants on the landscape between precipitation events, followed by a washoff event with a relatively high pollutant load. On the other hand, anticipated increases in average temperature and evaporation rate might not only reduce effective rainfall rates (resulting in less energy for transporting pollutants from the landscape) but also reduce the tidal exchange ratio in shallow estuaries (many of which are valuable recreational, commercial, and aesthetic natural resources). Here, we develop and apply a comprehensive watershed-scale model for simulating water quality in
Gonzalez, L.G. [Departamento de Electronica y Comunicaciones, Universidad de los Andes, nucleo la Hechicera, 5101 Merida (Venezuela); Figueres, E.; Garcera, G. [Grupo de Sistemas Electronicos Industriales, Universidad Politecnica de Valencia, Camino de vera s/n, 46022 Valencia (Spain); Carranza, O. [Escuela Superior de Computo, Instituto Politecnico Nacional, Av. Juan de Dios Batiz s/n, 07738 DF (Mexico)
2010-07-15
This paper presents an improved maximum-power-point tracking algorithm for wind-energy-conversion-systems. The proposed method significantly reduces the turbine mechanical stress with regard to conventional techniques, so that both the maintenance needs and the medium time between failures are expected to be improved. To achieve these objectives, a sensorless speed control loop receives its reference signal from a modified Perturb and Observe algorithm, in which the typical steps on the reference speed have been substituted by a fixed and well-defined slope ramp signal. As a result, it is achieved a soft dynamic response of both the torque and the speed of the wind turbine, so that the whole system suffers from a lower mechanical stress than with conventional P and O techniques. The proposed method has been applied to a wind turbine based on a permanent magnet synchronous generator operating at variable speed, which is connected to the distribution grid by means of a back to back converter. (author)
M. A. García-Sánchez
2016-07-01
Full Text Available Chlorophyll is a pyrrolic pigment with important optical properties, which is the reason it has been studied for many years. Recently, interest has been rising with respect to this molecule because of its outstanding physicochemical properties, particularly applicable to the design and development of luminescent materials, hybrid sensor systems, and photodynamic therapy devices for the treatment of cancer cells and bacteria. More recently, our research group has been finding evidence for the possibility of preserving these important properties of substrates containing chlorophyll covalently incorporated within solid pore matrices, such as SiO2, TiO2 or ZrO2 synthesized through the sol-gel process. In this work, we study the optical properties of silica xerogels organo-modified on their surface with allyl and phenyl groups and containing different concentrations of chlorophyll bonded to the pore walls, in order to optimize the fluorescence that these macrocyclic species displays in solution. The intention of this investigation was to determine the maximum chlorophyll a concentration at which this molecule can be trapped inside the pores of a given xerogel and to ascertain if this pigment remains trapped as a monomer, a dimer, or aggregate. Allyl and phenyl groups were deposited on the surface of xerogels in view of their important effects on the stability of the molecule, as well as over the fluorescence emission of chlorophyll; however, these organic groups allow the trapping of either chlorophyll a monomers or dimers. The determination of the above parameters allows finding the most adequate systems for subsequent in vitro or in vivo studies. The characterization of the obtained xerogels was performed through spectroscopic absorption, emission and excitation spectra. These hybrid systems can be employed as mimics of natural systems; the entrapment of chlorophyll inside pore matrices indicates that it is possible to exploit some of the most
ZHANG Xu-ping; YU Yue-qing
2005-01-01
Optimization of structural parameters aimed at improving the load carrying capacity of spatial flexible redundant manipulators is presented in this paper. In order to increase the ratio of load to mass of robots, the cross-sectional parameters and constructional parameters are optimized respectively. The cross-sectional and configurational parameters are optimized simultaneously. The numerical simulation of a 4R spatial manipulator is performed. The results show that the load capacity of robots has been greatly improved through the optimization strategies proposed in this paper.
Conditional Stochastic Processes Applied to Wave Load Predictions
Jensen, Jørgen Juncher
2015-01-01
The concept of conditional stochastic processes provides a powerful tool for evaluation and estimation of wave loads on ships and offshore structures. This article first considers conditional waves with a focus on critical wave episodes. Then the inherent uncertainty in the results is illustrated...
Optimization Formulations for the Maximum Nonlinear Buckling Load of Composite Structures
Lindgaard, Esben; Lund, Erik
2011-01-01
, benchmarked on a number of numerical examples of laminated composite structures for the maximization of the buckling load considering fiber angle design variables. The optimization formulations are based on either linear or geometrically nonlinear analysis and formulated as mathematical programming problems...... solved using gradient based techniques. The developed local criterion is formulated such it captures nonlinear effects upon loading and proves useful for both analysis purposes and as a criterion for use in nonlinear buckling optimization. © 2010 Springer-Verlag....
Feasibility of Applying Controllable Lubrication to Dynamically Loaded Journal Bearings
Estupinan, Edgar Alberto; Santos, Ilmar
2009-01-01
A multibody dynamic model of the main mechanical components of a hermetic reciprocating compressor is presented in this work. Considering that some of the mechanical elements are interconnected via thin fluid films, the multibody dynamic model is coupled to the equations from the dynamics...... levels, wear and power losses of the system components. From the point of view of actively controlled lubrication and specifically for the case of dynamically loaded journal bearings, the injection pressure should be controlled in time domain. However, taking into account that the gas pressure...... and reaction forces in a reciprocating compressor have a cyclic behavior, periodic oil pressure injection rules based on the instantaneous crank angle and load bearing condition can be established. In this paper, several bearing configurations working under different oil pressure injection rules conditions...
Maximum entropy method applied to deblurring images on a MasPar MP-1 computer
Bonavito, N. L.; Dorband, John; Busse, Tim
1991-01-01
A statistical inference method based on the principle of maximum entropy is developed for the purpose of enhancing and restoring satellite images. The proposed maximum entropy image restoration method is shown to overcome the difficulties associated with image restoration and provide the smoothest and most appropriate solution consistent with the measured data. An implementation of the method on the MP-1 computer is described, and results of tests on simulated data are presented.
Kaiadi, Mehrzad; Tunestål, Per; Johansson, Bengt
2010-01-01
High EGR rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark ignition Natural Gas engines. With stoichiometric conditions a three way catalyst can be used which means that regulated emissions can be kept at very low levels. Most of the heavy duty NG engines are diesel engines which are converted for SI operation. These engine's components are in common with the diesel-engine which put limits on higher exh...
Simons, Frederik J
2012-01-01
Topography and gravity are geophysical fields whose joint statistical structure derives from interface-loading processes modulated by the underlying mechanics of isostatic and flexural compensation in the shallow lithosphere. Under this dual statistical-mechanistic viewpoint an estimation problem can be formulated where the knowns are topography and gravity and the principal unknown the elastic flexural rigidity of the lithosphere. In the guise of an equivalent "effective elastic thickness", this important, geographically varying, structural parameter has been the subject of many interpretative studies, but precisely how well it is known or how best it can be found from the data, abundant nonetheless, has remained contentious and unresolved throughout the last few decades of dedicated study. The popular methods whereby admittance or coherence, both spectral measures of the relation between gravity and topography, are inverted for the flexural rigidity, have revealed themselves to have insufficient power to in...
Applying the maximum information principle to cell transmission model of tra-ffic flow
刘喜敏; 卢守峰
2013-01-01
This paper integrates the maximum information principle with the Cell Transmission Model (CTM) to formulate the velo-city distribution evolution of vehicle traffic flow. The proposed discrete traffic kinetic model uses the cell transmission model to cal-culate the macroscopic variables of the vehicle transmission, and the maximum information principle to examine the velocity distri-bution in each cell. The velocity distribution based on maximum information principle is solved by the Lagrange multiplier method. The advantage of the proposed model is that it can simultaneously calculate the hydrodynamic variables and velocity distribution at the cell level. An example shows how the proposed model works. The proposed model is a hybrid traffic simulation model, which can be used to understand the self-organization phenomena in traffic flows and predict the traffic evolution.
Impact of DG Configuration on Maximum Use of Load Supply Capability in Distribution Power Systems
Hong Liu
2014-01-01
Full Text Available Traditional distributed generators (DGs planning methods take network loss minimization as the main objective to optimize DG sites in feeders. The use of load supply capability (LSC in DG planning will precisely answer the questions how many DGs should be integrated, which transformer they should be connected to, and which type of DGs should be adopted. The main work of this paper is to analyze the impact of DGs on LSC so as to answer the three key questions. It resolves the planning problem through three steps: (i two LSC models considering DGs’ access are developed, in which two different transfer strategies are considered: direct load transfer and indirect load transfer; (ii the method of combined simple method and point estimate method is proposed. At last, based on a base case, when the configuration of DGs is changing, the impact of DGs on system LSC is studied. After the case study, the conclusion concerning the impact of load transfer strategy, DG capacities, and DG types on LSC is reached.
Applying Tabu Heuristic to Wind Influenced, Minimum Risk and Maximum Expected Coverage Routes
1997-02-01
31 111.3. GENERAL VEHICLE ROUTING PROBLEM .......................................................... 33...r. L3. Background The vehicle routing problem with maximum coverage is an extension of the classical general vehicle routing problem (GVRP). A general...review from the literature for the general vehicle routing problem includes Eilon et al. (1971) and Bodin (1983). Within a traditional deterministic
Flower Pollination Algorithm Applied for Different Economic Load Dispatch Problems
R. Prathiba
2014-05-01
Full Text Available Economic load dispatch (ELD is the main optimization task in power system operation. Minimizing the fuel cost by optimally setting the real power outputs from generators is the objective of ELD problem. In this work, ELD problem is addressed by considering three different cost functions. Real power generations are adjusted for minimizing the fuel cost by using flower pollination algorithm (FOA. This algorithm works on the basis of pollinating behavior of flowering plants. Unlike the other nature inspired algorithms, it follows only the levy flight mechanism for generating the population for the next generation. Being free from large number of parameters, the algorithm works well and there is no much difficulty in tuning to suit for different problems. The algorithm can be coded easily in any programming language. The proposed algorithm is tested on the standard IEEE-30 bus system and the results are compared with those of the other algorithms reported in the literature. The results are found to be improved and encouraging.
Prediction of Maximum Strain in Finocyl Port Case-bonded Solid Propellants under Pressure Loading
Himanshu Shekhar
2006-07-01
Full Text Available Finite element analysis of case-bonded solid propellants in finocyl port configuration hasbeen carried out using finite element method. The parametric studies have also been conductedfor loading conditions, material properties, and geometrical configurations. The results arepresented in the form of a universal power law, which can be utilised for primary assessmentof peak strain in any finocyl port propellant configuration without using finite element software.This eliminates dependence on finite element software for structural integrity analysis of solidpropellants in finocyl port configuration under port pressurisation. The results obtained by finiteelement analysis and power law are in close agreement.
Measurement of in-bore side loads and comparison to first maximum yaw
Donald E. Carlucci
2016-04-01
Full Text Available In-bore yaw of a projectile in a gun tube has been shown to result in range loss if the yaw is significant. An attempt was made to determine if relationships between in-bore yaw and projectile First Maximum Yaw (FMY were observable. Experiments were conducted in which pressure transducers were mounted near the muzzle of a 155 mm cannon in three sets of four. Each set formed a cruciform pattern to obtain a differential pressure across the projectile. These data were then integrated to form a picture of what the overall pressure distribution was along the side of the projectile. The pressure distribution was used to determine a magnitude and direction of the overturning moment acting on the projectile. This moment and its resulting angular acceleration were then compared to the actual first maximum yaw observed in the test. The degree of correlation was examined using various statistical techniques. Overall uncertainty in the projectile dynamics was between 20% and 40% of the mean values of FMY.
Measurement of in-bore side loads and comparison to first maximum yaw
Donald E. CARLUCCI; Ryan DECKER; Julio VEGA; Douglas RAY
2016-01-01
In-bore yaw of a projectile in a gun tube has been shown to result in range loss if the yaw is significant. An attempt was made to determine if relationships between in-bore yaw and projectile First Maximum Yaw (FMY) were observable. Experiments were conducted in which pressure transducers were mounted near the muzzle of a 155 mm cannon in three sets of four. Each set formed a cruciform pattern to obtain a differential pressure across the projectile. These data were then integrated to form a picture of what the overall pressure distribution was along the side of the projectile. The pressure distribution was used to determine a magnitude and direction of the overturning moment acting on the projectile. This moment and its resulting angular acceleration were then compared to the actual first maximum yaw observed in the test. The degree of correlation was examined using various statistical techniques. Overall uncertainty in the projectile dynamics was between 20%and 40%of the mean values of FMY.
Dumas, R; Cheze, L; Frossard, L
2009-11-01
Inverse dynamics is the most comprehensive method that gives access to the net joint forces and moments during walking. However it is based on assumptions (i.e., rigid segments linked by ideal joints) and it is known to be sensitive to the input data (e.g., kinematic derivatives, positions of joint centres and centre of pressure, inertial parameters). Alternatively, transducers can be used to measure directly the load applied on the residuum of transfemoral amputees. So, the purpose of this study was to compare the forces and moments applied on a prosthetic knee measured directly with the ones calculated by three inverse dynamics computations--corresponding to 3 and 2 segments, and "ground reaction vector technique"--during the gait of one patient. The maximum RMSEs between the estimated and directly measured forces (i.e., 56 N) and moment (i.e., 5 N m) were relatively small. However the dynamic outcomes of the prosthetic components (i.e., absorption of the foot, friction and limit stop of the knee) were only partially assessed with inverse dynamic methods.
THE GENERALIZED MAXIMUM LIKELIHOOD METHOD APPLIED TO HIGH PRESSURE PHASE EQUILIBRIUM
Lúcio CARDOZO-FILHO
1997-12-01
Full Text Available The generalized maximum likelihood method was used to determine binary interaction parameters between carbon dioxide and components of orange essential oil. Vapor-liquid equilibrium was modeled with Peng-Robinson and Soave-Redlich-Kwong equations, using a methodology proposed in 1979 by Asselineau, Bogdanic and Vidal. Experimental vapor-liquid equilibrium data on binary mixtures formed with carbon dioxide and compounds usually found in orange essential oil were used to test the model. These systems were chosen to demonstrate that the maximum likelihood method produces binary interaction parameters for cubic equations of state capable of satisfactorily describing phase equilibrium, even for a binary such as ethanol/CO2. Results corroborate that the Peng-Robinson, as well as the Soave-Redlich-Kwong, equation can be used to describe phase equilibrium for the following systems: components of essential oil of orange/CO2.Foi empregado o método da máxima verossimilhança generalizado para determinação de parâmetros de interação binária entre os componentes do óleo essencial de laranja e dióxido de carbono. Foram usados dados experimentais de equilíbrio líquido-vapor de misturas binárias de dióxido de carbono e componentes do óleo essencial de laranja. O equilíbrio líquido-vapor foi modelado com as equações de Peng-Robinson e de Soave-Redlich-Kwong usando a metodologia proposta em 1979 por Asselineau, Bogdanic e Vidal. A escolha destes sistemas teve como objetivo demonstrar que o método da máxima verosimilhança produz parâmetros de interação binária, para equações cúbicas de estado capazes de descrever satisfatoriamente até mesmo o equilíbrio para o binário etanol/CO2. Os resultados comprovam que tanto a equação de Peng-Robinson quanto a de Soave-Redlich-Kwong podem ser empregadas para descrever o equilíbrio de fases para o sistemas: componentes do óleo essencial de laranja/CO2.
Load-Bearing Tank-Applied Multi-Layer Insulation Project
National Aeronautics and Space Administration — The proposed load-bearing, tank-applied, multi-layer insulation system consists of a set of highly reflective radiation shields made from 1 mil thick aluminized...
Principle of maximum Fisher information from Hardy's axioms applied to statistical systems.
Frieden, B Roy; Gatenby, Robert A
2013-10-01
Consider a finite-sized, multidimensional system in parameter state a. The system is either at statistical equilibrium or general nonequilibrium, and may obey either classical or quantum physics. L. Hardy's mathematical axioms provide a basis for the physics obeyed by any such system. One axiom is that the number N of distinguishable states a in the system obeys N=max. This assumes that N is known as deterministic prior knowledge. However, most observed systems suffer statistical fluctuations, for which N is therefore only known approximately. Then what happens if the scope of the axiom N=max is extended to include such observed systems? It is found that the state a of the system must obey a principle of maximum Fisher information, I=I(max). This is important because many physical laws have been derived, assuming as a working hypothesis that I=I(max). These derivations include uses of the principle of extreme physical information (EPI). Examples of such derivations were of the De Broglie wave hypothesis, quantum wave equations, Maxwell's equations, new laws of biology (e.g., of Coulomb force-directed cell development and of in situ cancer growth), and new laws of economic fluctuation and investment. That the principle I=I(max) itself derives from suitably extended Hardy axioms thereby eliminates its need to be assumed in these derivations. Thus, uses of I=I(max) and EPI express physics at its most fundamental level, its axiomatic basis in math.
Saha, Ranajit; Pan, Sudip; Chattaraj, Pratim K
2016-11-05
The validity of the maximum hardness principle (MHP) is tested in the cases of 50 chemical reactions, most of which are organic in nature and exhibit anomeric effect. To explore the effect of the level of theory on the validity of MHP in an exothermic reaction, B3LYP/6-311++G(2df,3pd) and LC-BLYP/6-311++G(2df,3pd) (def2-QZVP for iodine and mercury) levels are employed. Different approximations like the geometric mean of hardness and combined hardness are considered in case there are multiple reactants and/or products. It is observed that, based on the geometric mean of hardness, while 82% of the studied reactions obey the MHP at the B3LYP level, 84% of the reactions follow this rule at the LC-BLYP level. Most of the reactions possess the hardest species on the product side. A 50% null hypothesis is rejected at a 1% level of significance.
Ranajit Saha
2016-11-01
Full Text Available The validity of the maximum hardness principle (MHP is tested in the cases of 50 chemical reactions, most of which are organic in nature and exhibit anomeric effect. To explore the effect of the level of theory on the validity of MHP in an exothermic reaction, B3LYP/6-311++G(2df,3pd and LC-BLYP/6-311++G(2df,3pd (def2-QZVP for iodine and mercury levels are employed. Different approximations like the geometric mean of hardness and combined hardness are considered in case there are multiple reactants and/or products. It is observed that, based on the geometric mean of hardness, while 82% of the studied reactions obey the MHP at the B3LYP level, 84% of the reactions follow this rule at the LC-BLYP level. Most of the reactions possess the hardest species on the product side. A 50% null hypothesis is rejected at a 1% level of significance.
Principle of Maximum Fisher Information from Hardy's Axioms Applied to Statistical Systems
Frieden, B R
2014-01-01
Consider a finite-sized, multidimensional system in parameter state a. The system is either at statistical equilibrium or general non-equilibrium, and may obey either classical or quantum physics. L. Hardy's mathematical axioms provide a basis for the physics obeyed by any such system. One axiom is that the number N of distinguishable states a in the system obeys N=max. This assumes that N is known as deterministic prior knowledge. However, most observed systems suffer statistical fluctuations, for which N is therefore only known approximately. Then what happens if the scope of the axiom N=max is extended to include such observed systems? It is found that the state a of the system must obey a principle of maximum Fisher information, I=I_{max}. This is important because many physical laws have been derived, assuming as a working hypothesis that I=I_{max}. These derivations include uses of the principle of Extreme physical information (EPI). Examples of such derivations were of the De Broglie wave hypothesis, q...
Validity of different prediction equations of the maximum load in mixed martial arts athletes
Jairo Laécio Guerra Filho
2014-12-01
Full Text Available The purpose of this study was to investigate the validity of different prediction equations to the one maximum repetition (1-RM test at the bench press exercise (BP with bar in mixed martial arts (MMA athletes. The sample was composed by 19 male MMA athletes (27.68 ± 6.19 years. The data collection was performed in two different moments: 1 in 1-RM test; 2 in submaximal test and their respective numbers of repetitions. The paired-sample t test was performed and was noted that, among the six equations compared with the 1-RM test, only the Adams (p= 0.337 and O’Conner’s (p= 0.250 equations showed no significant differences. However, there were high Pearson correlation and intraclass correlation coefficients (r= 0.924, ICC= 0.924; r= 0.944, ICC= 0.944, respectively. Nevertheless, all equations showed high correlations that ranged between 0.854 and 0.944. In conclusion, for estimation of 1-RM, the predictive equations based on Adams and O'Conner’s are valid in MMA athletes.
Shah, Kushal S; Saranathan, Archana; Koya, Bharath; Elias, John J
2015-01-01
A finite element analysis (FEA) modeling technique has been developed to characterize how varying the orientation of the patellar tendon influences the patellofemoral pressure distribution. To evaluate the accuracy of the technique, models were created from MRI images to represent five knees that were previously tested in vitro to determine the influence of hamstrings loading on patellofemoral contact pressures. Hamstrings loading increased the lateral and posterior orientation of the patellar tendon. Each model was loaded at 40°, 60°, and 80° of flexion with quadriceps force vectors representing the experimental loading conditions. The orientation of the patellar tendon was represented for the loaded and unloaded hamstrings conditions based on experimental measures of tibiofemoral alignment. Similar to the experimental data, simulated loading of the hamstrings within the FEA models shifted the center of pressure laterally and increased the maximum lateral pressure. Significant (p pressure and maximum lateral pressure from paired t-tests carried out at the individual flexion angles. The ability to replicate experimental trends indicates that the FEA models can be used for future studies focused on determining how variations in the orientation of the patellar tendon related to anatomical or loading variations or surgical procedures influence the patellofemoral pressure distribution.
Laurent Frossard, PhD
2013-08-01
Full Text Available The objectives of this study were to (1 record the inner-prosthesis loading during activities of daily living (ADLs, (2 present a set of variables comparing loading data, and (3 provide an example of characterization of two prostheses. The load was measured at 200 Hz using a multi-axial transducer mounted between the residuum and the knee of an individual with unilateral transfemoral amputation fitted with a bone-anchored prosthesis. The load was measured while using two different prosthetic knees, mechanical (PRO1 and microprocessor-controlled (PRO2, during six ADLs. The characteri-zation of the prostheses was achieved using a set of variables split into four categories, including temporal characteristics, maximum loading, loading slopes, and impulse. Approximately 360 gait cycles were analyzed for each prosthesis. PRO1 showed a cadence improved by 19% and 7%, a maximum force on the long axis reduced by 11% and 19%, and an impulse reduced by 32% and 15% during descent of incline and stairs compared with PRO2, respectively. This work confirmed that the proposed apparatus and characterization can reveal how changes of prosthetic components are translated into inner-prosthetic loading.
Kim, Sang M; Brannan, Kevin M; Zeckoski, Rebecca W; Benham, Brian L
2014-01-01
The objective of this study was to develop bacteria total maximum daily loads (TMDLs) for the Hardware River watershed in the Commonwealth of Virginia, USA. The TMDL program is an integrated watershed management approach required by the Clean Water Act. The TMDLs were developed to meet Virginia's water quality standard for bacteria at the time, which stated that the calendar-month geometric mean concentration of Escherichia coli should not exceed 126 cfu/100 mL, and that no single sample should exceed a concentration of 235 cfu/100 mL. The bacteria impairment TMDLs were developed using the Hydrological Simulation Program-FORTRAN (HSPF). The hydrology and water quality components of HSPF were calibrated and validated using data from the Hardware River watershed to ensure that the model adequately simulated runoff and bacteria concentrations. The calibrated and validated HSPF model was used to estimate the contributions from the various bacteria sources in the Hardware River watershed to the in-stream concentration. Bacteria loads were estimated through an extensive source characterization process. Simulation results for existing conditions indicated that the majority of the bacteria came from livestock and wildlife direct deposits and pervious lands. Different source reduction scenarios were evaluated to identify scenarios that meet both the geometric mean and single sample maximum E. coli criteria with zero violations. The resulting scenarios required extreme and impractical reductions from livestock and wildlife sources. Results from studies similar to this across Virginia partially contributed to a reconsideration of the standard's applicability to TMDL development.
Effect of applied load on the nondestructive measurement of concrete strength
Mahmoudabadi, E.; Amjad, U.; Kundu, T.; Saadatmanesh, H.
2014-03-01
Nondestructive measurement of the concrete strength is an important topic of research. Among different nondestructive testing (NDT) methods the ultrasonic pulse velocity (UPV) technique is the most popular method for concrete strength estimation. While measuring concrete strength by this method almost all researchers have neglected the effect of applied stress or load on the concrete member. In this investigation attempts were made to properly incorporate the effect of the applied load on the strength prediction of concrete specimens from UPV value. To achieve this goal, 4 groups of concrete specimens with different values of final strength were made. Materials used for making cylindrical specimens of 3 inch diameter and 6 inch height included regular Portland cement, water and two types of aggregate - fine and coarse. After applying the load on the specimen in multiple steps - up to 70% of its failure strength fc'- the time of flight (TOF) value was measured for every loading step. The recorded results showed that applied load on the member has significant effect on the measured UPV value on concrete specimens. Therefore, to find the strength of the concrete from the UPV value, the applied load on the sample should be considered as an important factor that cannot be neglected.
孙宗颀
2001-01-01
When a crack is subjected to shear force, crack branching usually occurs. Theoretical study shows that the crack branching under shear loading is caused by tensile stress, but not caused by shear fracture. The co-plane shear fracture could be obtained if compressive stress with given direction is applied to the specimen, subsequently, calculated shear fracture toughness, KⅡ C, is larger than KⅠ C. A prerequisite of possible occurrence of mode Ⅱ fracture was proposed. The study of shear fracture shows that the maximum circumferential stress theory considered its criterion as a parametric equation of a curve in KⅠ, KⅡ plane is incorrect; the predicted ratio KⅡ C/KⅠ C=0.866 is incorrect too.
The research of the maximum wind speed in Tomsk and calculations of dynamic load on antenna systems
Belan, B.; Belan, S.; Romanovskiy, O.; Girshtein, A.; Yanovich, A.; Baidali, S.; Terehov, S.
2017-01-01
The work is concerned with calculations and analysis of the maximum wind speed in Tomsk city. The data for analysis were taken from the TOR-station located in the north-eastern part of the city. The TOR-station sensors to measure a speed and a direction of wind are installed on the 10-meter meteorological mast. Wind is measured by M-63, which uses the standard approach and the program with one-minute averaging for wind gusts recording as well. According to the measured results in the research performed, the estimation of the dynamic and wind load on different types of antenna systems was performed. The work shows the calculations of wind load on ten types of antenna systems, distinguished by their different constructions and antenna areas. For implementation of calculations, we used methods developed in the Central Research and Development Institute of Building Constructions named after V.A. Kucherenko. The research results could be used for design engineering of the static antenna systems and mobile tracking systems for the distant objects.
Esfandiar, Habib; KoraYem, Moharam Habibnejad [Islamic Azad University, Tehran (Iran, Islamic Republic of)
2015-09-15
In this study, the researchers try to examine nonlinear dynamic analysis and determine Dynamic load carrying capacity (DLCC) in flexible manipulators. Manipulator modeling is based on Timoshenko beam theory (TBT) considering the effects of shear and rotational inertia. To get rid of the risk of shear locking, a new procedure is presented based on mixed finite element formulation. In the method proposed, shear deformation is free from the risk of shear locking and independent of the number of integration points along the element axis. Dynamic modeling of manipulators will be done by taking into account small and large deformation models and using extended Hamilton method. System motion equations are obtained by using nonlinear relationship between displacements-strain and 2nd PiolaKirchoff stress tensor. In addition, a comprehensive formulation will be developed to calculate DLCC of the flexible manipulators during the path determined considering the constraints end effector accuracy, maximum torque in motors and maximum stress in manipulators. Simulation studies are conducted to evaluate the efficiency of the method proposed taking two-link flexible and fixed base manipulators for linear and circular paths into consideration. Experimental results are also provided to validate the theoretical model. The findings represent the efficiency and appropriate performance of the method proposed.
W.R. Solonick
2003-04-01
Rapidly applied transient dynamic loads produce stresses and deflections in structures that typically exceed those from static loading conditions. Previous acceptance criteria for structures designed for rapidly applied transient dynamic loading limited stresses to those determined from elastic analysis. Different stress limits were established for different grades of structure depending upon the amount of permanent set considered acceptable. Structure allowed to sustain very limited permanent set is designed to stress limits not significantly greater than yield stress. Greater permanent set in structure under rapidly applied transient dynamic loading conditions is permitted by establishing stress limits that are significantly greater than yield stress but still provide adequate safety margin (with respect to failure). This paper presents a strain-based elastic-plastic (i.e., inelastic) analysis criterion developed as an alternative to the more conservative stress-based elastic analysis stress criterion for structures subjected to rapidly applied transient dynamic loading. The strain limits established are based on material ductility considerations only and are set as a fraction of the strain at ultimate stress obtained from an engineering stress/strain curve of the material. Strains limits are categorized by type as membrane or surface and by region as general, local , or concentrated. The application of the elastic-plastic criterion provides a more accurate, less conservative design/analysis basis for structures than that used in elastic stress-based analysis criteria, while still providing adequate safety margins.
Formation of metal-F bonds during frictional sliding : Influence of water and applied load
Shen, J. T.; Pei, Y. T.; De Hosson, J. Th. M.
2016-01-01
Effects of water lubrication and applied load on the formation of PTFE transfer films and metal-F bonds during sliding when PTFE filled composites sliding against steel and Al2O3 are investigated. In water lubricated conditions, XPS analysis reveals that a thin layer of water molecules at the slidin
Formation of metal-F bonds during frictional sliding : Influence of water and applied load
Shen, J. T.; Pei, Y. T.; De Hosson, J. Th. M.
2016-01-01
Effects of water lubrication and applied load on the formation of PTFE transfer films and metal-F bonds during sliding when PTFE filled composites sliding against steel and Al2O3 are investigated. In water lubricated conditions, XPS analysis reveals that a thin layer of water molecules at the
Harry X.ZHANG; Shaw L.YU
2008-01-01
One of the key challenges in the total max-imum daily load (TMDL) development process is how to define the critical condition for a receiving water-body. The main concern in using a continuous simu-lation approach is the absence of any guarantee that the most critical condition will be captured during the selected representative hydrologic period, given the scar-city of long-term continuous data. The objectives of this paper are to clearly address the critical condition in the TMDL development process and to compare continu-ous and evEnt-based approaches in defining critical con-dition during TMDL development for a waterbody impacted by both point and nonpoint source pollution. A practical, event-based critical flow-storm (CFS) approach was developed to explicitly addresses the crit-ical condition as a combination of a low stream flow and a storm event of a selected magnitude, both having cer-tain frequencies of occurrence. This paper illustrated the CFS concept and provided its theoretical basis using a derived analytical conceptual model. The CFS approach clearly defined a critical condition, obtained reasonable results and could be considered as an alternative method in TMDL development.
A New Crank Arm-Based Load Cell for the 3D Analysis of the Force Applied by a Cyclist
Alexandre Balbinot
2014-12-01
Full Text Available This report describes a new crank arm-based force platform designed to evaluate the three-dimensional force applied to the pedals by cyclists in real conditions. The force platform was designed to be fitted on a conventional competition bicycle crankset while data is transmitted wirelessly through a BluetoothTM module and also stored on a SD card. A 3D solid model is created in the SolidWorks (Dassault Systèmes SOLIDWORKS Corp. to analyze the static and dynamic characteristics of the crank arm by using the finite elements technique. Each crankset arm is used as a load cell based on strain gauges configured as three Wheatstone bridges. The signals are conditioned on a printed circuit board attached directly to the structure. The load cell showed a maximum nonlinearity error between 0.36% and 0.61% and a maximum uncertainty of 2.3% referred to the sensitivity of each channel. A roller trainer equipped with an optical encoder was also developed, allowing the measurement of the wheel’s instantaneous velocity.
A new crank arm-based load cell for the 3D analysis of the force applied by a cyclist.
Balbinot, Alexandre; Milani, Cleiton; Nascimento, Jussan da Silva Bahia
2014-12-03
This report describes a new crank arm-based force platform designed to evaluate the three-dimensional force applied to the pedals by cyclists in real conditions. The force platform was designed to be fitted on a conventional competition bicycle crankset while data is transmitted wirelessly through a Bluetooth™ module and also stored on a SD card. A 3D solid model is created in the SolidWorks (Dassault Systèmes SOLIDWORKS Corp.) to analyze the static and dynamic characteristics of the crank arm by using the finite elements technique. Each crankset arm is used as a load cell based on strain gauges configured as three Wheatstone bridges. The signals are conditioned on a printed circuit board attached directly to the structure. The load cell showed a maximum nonlinearity error between 0.36% and 0.61% and a maximum uncertainty of 2.3% referred to the sensitivity of each channel. A roller trainer equipped with an optical encoder was also developed, allowing the measurement of the wheel's instantaneous velocity.
EFFECT OF ESCAPE DEVICE FOR SUBMERGED FLOATING TUNNEL (SFT) ON HYDRODYNAMIC LOADS APPLIED TO SFT
DONG Man-sheng; MIAO Guo-ping; YONG Long-chang; NIU Zhong-rong; PANG Huan-ping; HOU Chao-qun
2012-01-01
This paper presents a potential approach to settle the problem of surviving major safety accidents in Submerged Floating Tunnel (SFT) that detachable emergency escape devices are set up outside SFT.The Computational Fluid Dynamics (CFD)technology is used to investigate the effect of emergency escape devices on the hydrodynamic load acting on SFT in uniform and oscillatory flows and water waves by numerical test.The governing equations,i.e.,the Reynolds-Averaged Navier-Stokes (RANS)equations and k - ε standard turbulence equations,are solved by the Finite Volume Method (FVM).Analytic solutions for the Airy wave are applied to set boundary conditions to generate water wave.The VOF method is used to trace the free surface.In uniform flow,hydrodynamic loads,applied to SFT with emergency escape device,reduce obviously.But,in oscillatory flow,it has little influence on hydrodynamic loads acting on SFT.Horizontal and vertical wave loads of SFT magnify to some extend due to emergency escape devices so that the influence of emergency escape devices on hydrodynamic loads of SFT should be taken into consideration when designed.
Rounds, Stewart A.; Sullivan, Annett B.
2013-01-01
Flow and water-quality models are being used to support the development of Total Maximum Daily Load (TMDL) plans for the Klamath River downstream of Upper Klamath Lake (UKL) in south-central Oregon. For riverine reaches, the RMA-2 and RMA-11 models were used, whereas the CE-QUAL-W2 model was used to simulate pooled reaches. The U.S. Geological Survey (USGS) was asked to review the most upstream of these models, from Link River Dam at the outlet of UKL downstream through the first pooled reach of the Klamath River from Lake Ewauna to Keno Dam. Previous versions of these models were reviewed in 2009 by USGS. Since that time, important revisions were made to correct several problems and address other issues. This review documents an assessment of the revised models, with emphasis on the model revisions and any remaining issues. The primary focus of this review is the 19.7-mile Lake Ewauna to Keno Dam reach of the Klamath River that was simulated with the CE-QUAL-W2 model. Water spends far more time in the Lake Ewauna to Keno Dam reach than in the 1-mile Link River reach that connects UKL to the Klamath River, and most of the critical reactions affecting water quality upstream of Keno Dam occur in that pooled reach. This model review includes assessments of years 2000 and 2002 current conditions scenarios, which were used to calibrate the model, as well as a natural conditions scenario that was used as the reference condition for the TMDL and was based on the 2000 flow conditions. The natural conditions scenario included the removal of Keno Dam, restoration of the Keno reef (a shallow spot that was removed when the dam was built), removal of all point-source inputs, and derivation of upstream boundary water-quality inputs from a previously developed UKL TMDL model. This review examined the details of the models, including model algorithms, parameter values, and boundary conditions; the review did not assess the draft Klamath River TMDL or the TMDL allocations
Effects of Applied Load on 6061-T6 Aluminum Joined Employing a Novel Friction Bonding Process
Burkes, Douglas E.; Hallinan, Neil P.; Shropshire, Karen L.; Wells, Peter B.
2008-12-01
Friction bonding is under consideration for use in mass production of plate-type nuclear fuels for research reactors. This article discusses the effects of applied load (the most important process parameter for fabrication of these fuels) on temperature distribution, microstructure, and mechanical properties. Friction bonding experiments showed that tool geometry caused temperature gradients across the tool surface. Temperatures at the joint interface suggested the advancing side of the tool produced a majority of the frictional heat, while the retreating side of the tool mainly forged the plasticized material while bonding increased with applied load. The microstructure across the tool surface was also altered and, as a function of applied load, affected the mechanical properties. The 6061 aluminum alloy had mechanical properties close to a T4 temper after processing. Results documented in this article will aid in continual enhancement of friction bonding for nuclear fuel plate fabrication, and will hopefully contribute to continued advancement of friction stir welding (FSW) state of the art.
Influence of applied load on wear behavior of C/C-Cu composites under electric current
Jian Yin
2017-04-01
Full Text Available Using carbon fiber needled fabrics with Cu-mesh and graphite powder as the preform, Cu mesh modified carbon/carbon(C/C-Cu composites were prepared by chemical vapor deposition (CVD with C3H6 and impregnation-carbonization (I/C with furan resin. C/C composites, as a comparison, were also prepared. Their microstructures and wear morphologies were observed by optical microscopy (OM and scanning electron microscope (SEM, respectively. Wear behavior of C/C and C/C-Cu composites under different applied loads were investigated on a pin-on-disc wear tester. The results show that Cu meshes are well dispersed and pyrolytic carbon is in rough laminar structure. Both C/C and C/C-Cu composites had good wear properties. The current-carrying capacity of C/C-Cu composites increases and the arc discharge is hindered as the applied load increases from 40 N to 80 N. Both C/C and C/C-Cu composites had good wear properties. The mass wear rate of C/C-Cu composites under 80 N was only 4.2% of that under 60 N. In addition, C/C-Cu composites represent different wear behaviors because wear mechanisms of arc erosion, abrasive wear, adhesive wear, and oxidative wear are changing under different applied loads.
Yangwei Liu
2014-11-01
Full Text Available Control of corner separation has attracted much interest due to its improvement of performance and energy utilization in turbomachinery. Numerical studies have been performed under both design and off-design flow conditions to investigate the effects of boundary layer suction (BLS on corner separation in a highly loaded compressor cascade. Two new BLS slot configurations are proposed and a total of five suction slot configurations were studied and compared. Averaged static pressure rise, exit loss coefficient, passage blockage and flow turning angle have been given and compared systematically over a range of operation incidence angles. Distributions of significant loss removal, blade loading, exit deviation and total pressure loss at 3 degree and 7 degree incidence have also been studied. Under the same suction mass flows of 0.7% of the inlet mass flows, the pitchwise suction slot on the endwall shows a better optimal performance over the whole operation incidence among single suction slots. By using of the new proposed compound slot configuration with one spanwise slot on the blade suction side and one pitchwise slot on the endwall, the maximum reduction of total pressure loss at 7 degree incidence can be 39.4%.
Shen, Hua
2016-10-19
A maximum-principle-satisfying space-time conservation element and solution element (CE/SE) scheme is constructed to solve a reduced five-equation model coupled with the stiffened equation of state for compressible multifluids. We first derive a sufficient condition for CE/SE schemes to satisfy maximum-principle when solving a general conservation law. And then we introduce a slope limiter to ensure the sufficient condition which is applicative for both central and upwind CE/SE schemes. Finally, we implement the upwind maximum-principle-satisfying CE/SE scheme to solve the volume-fraction-based five-equation model for compressible multifluids. Several numerical examples are carried out to carefully examine the accuracy, efficiency, conservativeness and maximum-principle-satisfying property of the proposed approach.
NSGIC State | GIS Inventory — Environmental Modeling dataset current as of 1999. Florida Adopted TMDLs. What is a TMDL (Total Maximum Daily Load)? A scientific determination of the maximum amount...
Li, Yonghui; Wu, Qiuwei; Zhu, Haiyu
2015-01-01
Based on the benchmark solid oxide fuel cell (SOFC) dynamic model for power system studies and the analysis of the SOFC operating conditions, the nonlinear programming (NLP) optimization method was used to determine the maximum electrical efficiency of the grid-connected SOFC subject...
Maximum Likelihood Signal Extraction Method Applied to 3.4 years of CoGeNT Data
Aalseth, C E; Colaresi, J; Collar, J I; Leon, J Diaz; Fast, J E; Fields, N E; Hossbach, T W; Knecht, A; Kos, M S; Marino, M G; Miley, H S; Miller, M L; Orrell, J L; Yocum, K M
2014-01-01
CoGeNT has taken data for over 3 years, with 1136 live days of data accumulated as of April 23, 2013. We report on the results of a maximum likelihood analysis to extract any possible dark matter signal present in the collected data. The maximum likelihood signal extraction uses 2-dimensional probability density functions (PDFs) to characterize the anticipated variations in dark matter interaction rates for given observable nuclear recoil energies during differing periods of the Earth's annual orbit around the Sun. Cosmogenic and primordial radioactivity backgrounds are characterized by their energy signatures and in some cases decay half-lives. A third parameterizing variable -- pulse rise-time -- is added to the likelihood analysis to characterize slow rising pulses described in prior analyses. The contribution to each event category is analyzed for various dark matter signal hypotheses including a dark matter standard halo model and a case with free oscillation parameters (i.e., amplitude, period, and phas...
Chad Pope; Larry L. Taylor; Soon Sam Kim
2007-02-01
This document represents a summary version of the criticality analysis done to support loading SNF in a Type 1a basket/standard canister combination. Specifically, this engineering design file (EDF) captures the information pertinent to the intact condition of four fuel types with different fissile loads and their calculated reactivities. These fuels are then degraded into various configurations inside a canister without the presence of significant moderation. The important aspect of this study is the portrayal of the fuel degradation and its effect on the reactivity of a single canister given the supposition there will be continued moderation exclusion from the canister. Subsequent analyses also investigate the most reactive ‘dry’ canister in a nine canister array inside a hypothetical transport cask, both dry and partial to complete flooding inside the transport cask. The analyses also includes a comparison of the most reactive configuration to other benchmarked fuels using a software package called TSUNAMI, which is part of the SCALE 5.0 suite of software.
Furbish, David J.; Schmeeckle, Mark; Schumer, Rina; Fathel, Siobhan L.
2016-01-01
We describe the most likely forms of the probability distributions of bed load particle velocities, accelerations, hop distances, and travel times, in a manner that formally appeals to inferential statistics while honoring mechanical and kinematic constraints imposed by equilibrium transport conditions. The analysis is based on E. Jaynes's elaboration of the implications of the similarity between the Gibbs entropy in statistical mechanics and the Shannon entropy in information theory. By maximizing the information entropy of a distribution subject to known constraints on its moments, our choice of the form of the distribution is unbiased. The analysis suggests that particle velocities and travel times are exponentially distributed and that particle accelerations follow a Laplace distribution with zero mean. Particle hop distances, viewed alone, ought to be distributed exponentially. However, the covariance between hop distances and travel times precludes this result. Instead, the covariance structure suggests that hop distances follow a Weibull distribution. These distributions are consistent with high-resolution measurements obtained from high-speed imaging of bed load particle motions. The analysis brings us closer to choosing distributions based on our mechanical insight.
Cedola, A.P., E-mail: ariel.cedola@ing.unlp.edu.a [Grupo de Estudio de Materiales y Dispositivos Electronicos (GEMyDE), Dpto. Electrotecnia, Facultad de Ingenieria, Universidad Nacional de La Plata, 48 y 116, C.C. 91, La Plata 1900, Buenos Aires (Argentina); Cappelletti, M.A. [Grupo de Estudio de Materiales y Dispositivos Electronicos (GEMyDE), Dpto. Electrotecnia, Facultad de Ingenieria, Universidad Nacional de La Plata, 48 y 116, C.C. 91, La Plata 1900, Buenos Aires (Argentina); Casas, G. [Grupo de Estudio de Materiales y Dispositivos Electronicos (GEMyDE), Dpto. Electrotecnia, Facultad de Ingenieria, Universidad Nacional de La Plata, 48 y 116, C.C. 91, La Plata 1900, Buenos Aires (Argentina); Universidad Nacional de Quilmes, Roque Saenz Pena 352, Bernal 1876, Buenos Aires (Argentina); Peltzer y Blanca, E.L. [Grupo de Estudio de Materiales y Dispositivos Electronicos (GEMyDE), Dpto. Electrotecnia, Facultad de Ingenieria, Universidad Nacional de La Plata, 48 y 116, C.C. 91, La Plata 1900, Buenos Aires (Argentina); Instituto de Fisica de Liquidos y Sistemas Biologicos (IFLYSIB), CONICET - UNLP - CIC, La Plata 1900, Buenos Aires (Argentina)
2011-02-11
An iterative method based on numerical simulations was developed to enhance the proton radiation tolerance and the responsivity of Si PIN photodiodes. The method allows to calculate the optimal values of the intrinsic layer thickness and the incident light wavelength, in function of the light intensity and the maximum proton fluence to be supported by the device. These results minimize the effects of radiation on the total reverse current of the photodiode and maximize its response to light. The implementation of the method is useful in the design of devices whose operation point should not suffer variations due to radiation.
Lemaire, H.; Barat, E.; Carrel, F.; Dautremer, T.; Dubos, S.; Limousin, O.; Montagu, T.; Normand, S.; Schoepff, V. [CEA, Gif-sur-Yvette, F-91191 (France); Amgarou, K.; Menaa, N. [CANBERRA, 1, rue des Herons, Saint Quentin en Yvelines, F-78182 (France); Angelique, J.-C. [LPC, 6, boulevard du Marechal Juin, F-14050 (France); Patoz, A. [CANBERRA, 10, route de Vauzelles, Loches, F-37600 (France)
2015-07-01
In this work, we tested Maximum likelihood expectation-maximization (MLEM) algorithms optimized for gamma imaging applications on two recent coded mask gamma cameras. We respectively took advantage of the characteristics of the GAMPIX and Caliste HD-based gamma cameras: noise reduction thanks to mask/anti-mask procedure but limited energy resolution for GAMPIX, high energy resolution for Caliste HD. One of our short-term perspectives is the test of MAPEM algorithms integrating specific prior values for the data to reconstruct adapted to the gamma imaging topic. (authors)
Chen Pоуu
2013-01-01
Full Text Available Products made overseas but sold in Taiwan are very common. Regarding the cross-border or interregional production and marketing of goods, inventory decision-makers often have to think about how to determine the amount of purchases per cycle, the number of transport vehicles, the working hours of each transport vehicle, and the delivery by ground or air transport to sales offices in order to minimize the total cost of the inventory in unit time. This model assumes that the amount of purchases for each order cycle should allow all rented vehicles to be fully loaded and the transport times to reach the upper limit within the time period. The main research findings of this study included the search for the optimal solution of the integer planning of the model and the results of sensitivity analysis.
Effect of Sintering Temperature and Applied Load on Anode-Supported Electrodes for SOFC Application
Xuan-Vien Nguyen
2016-08-01
Full Text Available Anode-supported cells are prepared by a sequence of hot pressing and co-sintering processes for solid oxide fuel cell (SOFC applications. Commercially available porous anode tape (NiO/YSZ = 50 wt %/50 wt %, anode tape (NiO/YSZ = 30 wt %/70 wt %, and YSZ are used as the anode substrate, anode functional layer, and electrolyte layer, respectively. After hot pressing, the stacked layers are then sintered at different temperatures (1250 °C, 1350 °C, 1400 °C and 1450 °C for 5 h in air. Different compressive loads are applied during the sintering process. An (La,SrMnO3 (LSM paste is coated on the post-sintered anode-supported electrolyte surface as the cathode, and sintered at different temperatures (1100 °C, 1150 °C, 1200 °C and 1250 °C for 2 h in air to generate anode-supported cells with dimensions of 60 × 60 mm2 (active reaction area of 50 × 50 mm2. SEM is used to investigate the anode structure of the anode-supported cells. In addition, confocal laser scanning microscopy is used to investigate the roughness of the cathode surfaces. At sintering temperatures of 1400 °C and 1450 °C, there is significant grain growth in the anode. Furthermore, the surface of the cathode is smoother at a firing temperature of 1200 °C. It is also found that the optimal compressive load of 1742 Pa led to a flatness of 168 µm/6 cm and a deformation of 0.72%. The open circuit voltage and power density of the anode-supported cell at 750 °C were 1.0 V and 178 mW·cm−2, respectively.
Kelisani, M. Dayyani; Doebert, S.; Aslaninejad, M.
2016-08-01
The critical process of beam loading compensation in high intensity accelerators brings under control the undesired effect of the beam induced fields to the accelerating structures. A new analytical approach for optimizing standing wave accelerating structures is found which is hugely fast and agrees very well with simulations. A perturbative analysis of cavity and waveguide excitation based on the Bethe theorem and normal mode expansion is developed to compensate the beam loading effect and excite the maximum field gradient in the cavity. The method provides the optimum values for the coupling factor and the cavity detuning. While the approach is very accurate and agrees well with simulation software, it massively shortens the calculation time compared with the simulation software.
Kelisani, M. Dayyani, E-mail: mdayyani@cern.ch [Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); European Organization for Nuclear Research (CERN), BE Department, CH-1211 Geneva 23 (Switzerland); Doebert, S. [European Organization for Nuclear Research (CERN), BE Department, CH-1211 Geneva 23 (Switzerland); Aslaninejad, M. [Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)
2016-08-21
The critical process of beam loading compensation in high intensity accelerators brings under control the undesired effect of the beam induced fields to the accelerating structures. A new analytical approach for optimizing standing wave accelerating structures is found which is hugely fast and agrees very well with simulations. A perturbative analysis of cavity and waveguide excitation based on the Bethe theorem and normal mode expansion is developed to compensate the beam loading effect and excite the maximum field gradient in the cavity. The method provides the optimum values for the coupling factor and the cavity detuning. While the approach is very accurate and agrees well with simulation software, it massively shortens the calculation time compared with the simulation software.
Makeev, Andrey; Ikejimba, Lynda; Lo, Joseph Y.; Glick, Stephen J.
2016-03-01
Although digital mammography has reduced breast cancer mortality by approximately 30%, sensitivity and specificity are still far from perfect. In particular, the performance of mammography is especially limited for women with dense breast tissue. Two out of every three biopsies performed in the U.S. are unnecessary, thereby resulting in increased patient anxiety, pain, and possible complications. One promising tomographic breast imaging method that has recently been approved by the FDA is dedicated breast computed tomography (BCT). However, visualizing lesions with BCT can still be challenging for women with dense breast tissue due to the minimal contrast for lesions surrounded by fibroglandular tissue. In recent years there has been renewed interest in improving lesion conspicuity in x-ray breast imaging by administration of an iodinated contrast agent. Due to the fully 3-D imaging nature of BCT, as well as sub-optimal contrast enhancement while the breast is under compression with mammography and breast tomosynthesis, dedicated BCT of the uncompressed breast is likely to offer the best solution for injected contrast-enhanced x-ray breast imaging. It is well known that use of statistically-based iterative reconstruction in CT results in improved image quality at lower radiation dose. Here we investigate possible improvements in image reconstruction for BCT, by optimizing free regularization parameter in method of maximum likelihood and comparing its performance with clinical cone-beam filtered backprojection (FBP) algorithm.
2014-01-01
International audience; Calculations of the CABRI REP-Na5 pulse were performed with the ALCYONE code in order to determine the evolution of the thermomechanical loading applied on the cladding tube during the Pellet-Cladding Mechanical Interaction (PCMI) phase of a rapid Reactivity Initiated Accident (RIA) initiated at 280 °C that lasted 8.8 ms. The evolution of the following parameters are reported: the cladding temperature, heating rate, strain rate and loading biaxiality. The impact of the...
Ma, Xiaodong; Rudnicki, John W.; Haimson, Bezalel C.
2017-04-01
We performed an extensive suite of true triaxial experiments in two porous sandstones, Bentheim (porosity ≈ 24%) and Coconino (17%). The experiments were conducted using a novel loading path, which maintains constant Lode angle (Θ) throughout the test. This path enabled the examination of the effects of Lode angle and mean stress on failure (σoct,f). Our tests covered σ3 magnitudes between 0 and 150 MPa and of Θ at -30° (axisymmetric extension), -16°, 0°, +11°, +21°, and +30° (axisymmetric compression). Test results revealed the respective contribution of each of the two stress invariants to failure stress, failure plane angle, and failure mode. In both sandstones, the shear stress required for failure increases with mean stress but decreases with Θ when shear failure mode dominates. However, the dependence of failure stress on mean stress and Θ is reversed when the compactive failure mode is in control. The compactive failure mode was evident in Bentheim sandstone when compaction bands were observed under high mean stress. The Coconino sandstone did not reach the compactive failure regime within the maximum confinement applied. The failure plane angle monotonically decreases with increasing mean stress and Θ. For Coconino sandstone, failure plane angle varies between 80° and 50° for σoct,f between 50 and 450 MPa whereas it drops to 0° as σoct,f, approaches 250 MPa in Bentheim sandstone. We employed the bifurcation theory to relate the stress conditions at failure to the development of failure planes. The theory is in qualitative agreement with the experimental data.
An examination and a comparison of the relative merits of the finite element and Fourier series methods of solving radially loaded circular ring...both methods under most conditions. The Fourier series method is superior for solving problems with a distributed load condition. The finite element
Applying graph partitioning methods in measurement-based dynamic load balancing
Bhatele, Abhinav [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fourestier, Sebastien [Univ. of Bordeaux (France). Bordeaux Lab. for Research in Computer Science; Menon, Harshitha [Univ. of Illinois, Urbana-Champaign, IL (United States); Kale, Laxmikant V. [Univ. of Illinois, Urbana-Champaign, IL (United States); Pellegrini, Francois [Univ. of Bordeaux (France). Bordeaux Lab. for Research in Computer Science
2011-09-26
Load imbalance leads to an increasing waste of resources as an application is scaled to more and more processors. Achieving the best parallel efficiency for a program requires optimal load balancing which is a NP-hard problem. However, finding near-optimal solutions to this problem for complex computational science and engineering applications is becoming increasingly important. Charm++, a migratable objects based programming model, provides a measurement-based dynamic load balancing framework. This framework instruments and then migrates over-decomposed objects to balance computational load and communication at runtime. This paper explores the use of graph partitioning algorithms, traditionally used for partitioning physical domains/meshes, for measurement-based dynamic load balancing of parallel applications. In particular, we present repartitioning methods developed in a graph partitioning toolbox called SCOTCH that consider the previous mapping to minimize migration costs. We also discuss a new imbalance reduction algorithm for graphs with irregular load distributions. We compare several load balancing algorithms using microbenchmarks on Intrepid and Ranger and evaluate the effect of communication, number of cores and number of objects on the benefit achieved from load balancing. New algorithms developed in SCOTCH lead to better performance compared to the METIS partitioners for several cases, both in terms of the application execution time and fewer number of objects migrated.
Eggleston, Jack
2009-01-01
Due to elevated levels of methylmercury in fish, three streams in the Shenandoah Valley of Virginia have been placed on the State's 303d list of contaminated waters. These streams, the South River, the South Fork Shenandoah River, and parts of the Shenandoah River, are downstream from the city of Waynesboro, where mercury waste was discharged from 1929-1950 at an industrial site. To evaluate mercury contamination in fish, this total maximum daily load (TMDL) study was performed in a cooperative effort between the U.S. Geological Survey, the Virginia Department of Environmental Quality, and the U.S. Environmental Protection Agency. The investigation focused on the South River watershed, a headwater of the South Fork Shenandoah River, and extrapolated findings to the other affected downstream rivers. A numerical model of the watershed, based on Hydrological Simulation Program-FORTRAN (HSPF) software, was developed to simulate flows of water, sediment, and total mercury. Results from the investigation and numerical model indicate that contaminated flood-plain soils along the riverbank are the largest source of mercury to the river. Mercury associated with sediment accounts for 96 percent of the annual downstream mercury load (181 of 189 kilograms per year) at the mouth of the South River. Atmospherically deposited mercury contributes a smaller load (less than 1 percent) as do point sources, including current discharge from the historic industrial source area. In order to determine how reductions of mercury loading to the stream could reduce methylmercury concentrations in fish tissue below the U.S. Environmental Protection Agency criterion of 0.3 milligrams per kilogram, multiple scenarios were simulated. Bioaccumulation of mercury was expressed with a site-specific exponential relation between aqueous total mercury and methylmercury in smallmouth bass, the indicator fish species. Simulations indicate that if mercury loading were to decrease by 98.9 percent from 189
Sensing Applied Load and Damage Effects in Composites with Nondestructive Techniques
2017-05-01
used in industry based on materials such as glass fiber, Kevlar, and carbon fiber combined with various types of epoxy.4,6 Carbon fiber-reinforced...coupons were composed of Torayca T700G/2510 unidirectional carbon fiber prepreg material. Unidirectional ply properties were given by the manufacturer...into tension- tension fatigue testing. Initial loading is done slowly and in steps to capture data while the composite sample is under loading but
The cost of chronic stress in childhood: understanding and applying the concept of allostatic load.
Katz, Debra A; Sprang, Ginny; Cooke, Circe
2012-09-01
This article explores the concept of allostatic load and its utility as an integrative framework for thinking about the impact of chronic stress on children and adolescents. Allostatic load refers to the failure or exhaustion of normal physiologic processes that occurs in response to severe, frequent, or chronic stressors. This persistent physiologic dysregulation may lead to secondary health problems such as immunosuppression, obesity, atherosclerosis, and hypertension. Allostatic load can be measured and followed as a composite index of a group of physiologic parameters which fall outside of a normal range. Although research regarding allostatic load in children is limited, this article explores relevant studies and identifies ways in which the concept of allostatic load can be used to broaden approaches to assessment, case formulation, and treatment in children. The concept of allostatic load may be of particular interest to psychodynamic psychiatrists in recognizing the ways in which chronic stress and adverse childhood experiences lead not only to negative psychological sequelae but also to long-term health consequences including the possibility of premature death. It underscores the importance of monitoring patients' physical as well as psychological health and thinking about the complex interrelations between the two.
Ellebæk, Mark Bremholm; Qvist, Niels; Schrøder, Henrik Daa; Rasmussen, Lars
2016-06-01
Introduction The treatment of esophageal atresia (OA) is challenging. The main goal is to achieve primary anastomosis. We have previously demonstrated in a pig model that intramural injection of botulinum toxin type A (BTX-A) resulted in significant elongation of the esophagus during tensioning until bursting point. The objectives of the present study were to investigate the influence of different amounts of intramural BTX-A on the stretch-tension characteristics and histological changes of the esophagus in piglets. Materials and Methods A total of 52 piglets were randomized to four groups receiving 2, 4, or 8 units/kg of BTX-A or isotonic saline (placebo). After a 1-hour of rest the esophagus was harvested and subjected to a stretch-tension test and histological examination to assess changes in the density of presynaptic vesicles in the nerve cells. Results Overall, 9 of the 52 animals were excluded from analysis due to problems with the stretch-tension test or death from anesthesia. The maximum loads were higher in the BTX-A groups (2 units/kg: +2.1 N; 4 units/kg: +1.3 N; 8 units/kg: +1.9 N) than the placebo (p = 0.046). There were no significant differences in percentage elongation, or histology. Conclusions This study demonstrated that injection of 2 units/kg BTX-A into a nonanastomosed esophageal wall resulted in a modest increase in the maximum load achieved before bursting; this may be due to the muscle-relaxant effect of BTX-A. BTX-A injection produced no significant effects on elongation or esophageal histology. The clinical usefulness of BTX-A in treatment of OA is still unclear. Georg Thieme Verlag KG Stuttgart · New York.
Bikakis, GSE; Savaidis, A.; Zalimidis, P.; Tsitos, S.
2016-11-01
Fiber-metal laminates are hybrid composite materials, consisting of alternating metal layers bonded to fiber-reinforced prepreg layers. GLARE (GLAss REinforced) belongs to this new family of materials. GLARE is the most successful fiber-metal laminate up to now and is currently being used for the construction of primary aerospace structures, such as the fuselage of the Airbus A380 air plane. Impact properties are very important in aerospace structures, since impact damage is caused by various sources, such as maintenance damage from dropped tools, collision between service cars or cargo and the structure, bird strikes and hail. The principal objective of this article is to evaluate the influence of the Metal Volume Fraction (MVF) on the low velocity impact response of GLARE fiber-metal laminates. Previously published differential equations of motion are employed for this purpose. The low velocity impact behavior of various circular GLARE plates is predicted and characteristic values of impact variables, which represent the impact phenomenon, are evaluated versus the corresponding MVF of the examined GLARE material grades. The considered GLARE plates are subjected to low velocity impact under identical impact conditions. A strong effect of the MVF on the maximum impact load and a significant effect on the maximum plate deflection of GLARE plates has been found.
Hellouin de Menibus, Arthur; Sercombe, Jerome; Auzoux, Quentin; Poussard, Christophe
2014-10-01
Calculations of the CABRI REP-Na5 pulse were performed with the ALCYONE code in order to determine the evolution of the thermomechanical loading applied on the cladding tube during the Pellet-Cladding Mechanical Interaction (PCMI) phase of a rapid Reactivity Initiated Accident (RIA) initiated at 280 °C that lasted 8.8 ms. The evolution of the following parameters are reported: the cladding temperature, heating rate, strain rate and loading biaxiality. The impact of these parameters on the cladding mechanical behavior and fracture are then briefly reviewed.
Ma, Guoming; Mao, Naiqiang; Li, Yabo; Jiang, Jun; Zhou, Hongyang; Li, Chengrong
2016-06-21
Heavy ice coating of high-voltage overhead transmission lines may lead to conductor breakage and tower collapse causing the unexpected interrupt of power supply. The optical load cell applied in ice monitoring systems is immune to electromagnetic interference and has no need of a power supply on site. Therefore, it has become a hot research topic in China and other countries. In this paper, to solve the problem of eccentric load in measurement, we adopt the shearing structure with additional grooves to improve the strain distribution and acquire good repeatability. Then, the fiber Bragg grating (FBG) with a permanent weldable package are mounted onto the front/rear groove of the elastic element by spot welding, the direction deviation of FBGs is 90° from each other to achieve temperature compensation without an extra FBG. After that, protection parts are designed to guarantee high sensitivity for a light load condition and industrial safety under a heavy load up to 65 kN. The results of tension experiments indicate that the sensitivity and resolution of the load cell is 0.1285 pm/N and 7.782 N in the conventional measuring range (0-10 kN). Heavy load tension experiments prove that the protection structure works and the sensitivity and resolution are not changed after several high load (65 kN) cycles. In addition, the experiment shows that the resolution of the sensor is 87.79 N in the large load range, allowing the parameter to be used in heavy icing monitoring.
de Araujo Guerra Grangeia, Tiago; de Jorge, Bruno; Franci, Daniel; Martins Santos, Thiago; Vellutini Setubal, Maria Silvia; Schweller, Marcelo; de Carvalho-Filho, Marco Antonio
2016-01-01
Emergency clerkships expose students to a stressful environment that require multiple tasks, which may have a direct impact on cognitive load and motivation for learning. To address this challenge, Cognitive Load Theory and Self Determination Theory provided the conceptual frameworks to the development of a Moodle-based online Emergency Medicine course, inspired by real clinical cases. Three consecutive classes (2013-2015) of sixth-year medical students (n = 304) participated in the course, during a curricular and essentially practical emergency rotation. "Virtual Rounds" provided weekly virtual patients in narrative format and meaningful schemata to chief complaints, in order to simulate real rounds at Emergency Unit. Additional activities such as Extreme Decisions, Emergency Quiz and Electrocardiographic challenge offered different views of emergency care. Authors assessed student´s participation and its correlation with their academic performance. A survey evaluated students´ opinions. Students graduating in 2015 answered an online questionnaire to investigate cognitive load and motivation. Each student produced 1965 pageviews and spent 72 hours logged on. Although Clinical Emergency rotation has two months long, students accessed the online course during an average of 5.3 months. Virtual Rounds was the most accessed activity, and there was positive correlations between the number of hours logged on the platform and final grades on Emergency Medicine. Over 90% of students felt an improvement in their clinical reasoning and considered themselves better prepared for rendering Emergency care. Considering a Likert scale from 1 (minimum load) to 7 (maximum load), the scores for total cognitive load were 4.79±2.2 for Virtual Rounds and 5.56±1.96 for real medical rounds(pmotivational conceptual frameworks, seems to be a strong tool to engage students in learning. It may support them to manage the cognitive challenges involved in clinical care and increase their
Tiago de Araujo Guerra Grangeia
Full Text Available Emergency clerkships expose students to a stressful environment that require multiple tasks, which may have a direct impact on cognitive load and motivation for learning. To address this challenge, Cognitive Load Theory and Self Determination Theory provided the conceptual frameworks to the development of a Moodle-based online Emergency Medicine course, inspired by real clinical cases.Three consecutive classes (2013-2015 of sixth-year medical students (n = 304 participated in the course, during a curricular and essentially practical emergency rotation. "Virtual Rounds" provided weekly virtual patients in narrative format and meaningful schemata to chief complaints, in order to simulate real rounds at Emergency Unit. Additional activities such as Extreme Decisions, Emergency Quiz and Electrocardiographic challenge offered different views of emergency care. Authors assessed student´s participation and its correlation with their academic performance. A survey evaluated students´ opinions. Students graduating in 2015 answered an online questionnaire to investigate cognitive load and motivation.Each student produced 1965 pageviews and spent 72 hours logged on. Although Clinical Emergency rotation has two months long, students accessed the online course during an average of 5.3 months. Virtual Rounds was the most accessed activity, and there was positive correlations between the number of hours logged on the platform and final grades on Emergency Medicine. Over 90% of students felt an improvement in their clinical reasoning and considered themselves better prepared for rendering Emergency care. Considering a Likert scale from 1 (minimum load to 7 (maximum load, the scores for total cognitive load were 4.79±2.2 for Virtual Rounds and 5.56±1.96 for real medical rounds(p<0,01.A real-world inspired online course, based on cognitive and motivational conceptual frameworks, seems to be a strong tool to engage students in learning. It may support them to
Applying Cognitive Load Theory to the Redesign of a Conventional Database Systems Course
Mason, Raina; Seton, Carolyn; Cooper, Graham
2016-01-01
Cognitive load theory (CLT) was used to redesign a Database Systems course for Information Technology students. The redesign was intended to address poor student performance and low satisfaction, and to provide a more relevant foundation in database design and use for subsequent studies and industry. The original course followed the conventional…
N. Sapawe
2014-12-01
Full Text Available The vegetable oil based lubricant as lubricant in various applications were intensified and eyed by the industry due to its superior tribological properties, and has potential to replace petroleum based lubricants. Palm olein could be suitable and attractive candidate as the lubricant to be studied due to its good advantages and large production in country. Thus, in the study the behavior of RBD palm olein characteristic was investigated by pin on disk experiment in which the hemispherical pin was loaded against the rotating grooved disk. The experiments by sliding were performed in pin on disk tester using titanium as material for both hemispherical pin and grooved disk. The test were implemented by dropping 5 ml of RBD palm olein as lubricating oil on sliding surface at different loads applied which were 5N, 20N, 40N and 80N. The wear rate of the pin and friction coefficient was also investigated. The weight loss and surface roughness before and after experiment were analyzed. All the results obtained were compared to hydraulic oil and paraffinic mineral oil. From the analysis, friction coefficient acquired lubricated with RBD palm olein was the lowest for both conditions. Wear rate obtained for three lubricants increased from 5N to 20N load, then decreased after 40N load and increased again after 80N load exerted. Wear obtained lubricated with hydraulic oil shows the lowest value compared to paraffinic mineral oil and RBD palm olein.
M. Girotto
2012-06-01
Full Text Available Esta pesquisa teve como objetivo avaliar a velocidade e intensidade de ação do hexazinone isolado e em mistura com outros inibidores do fotossistema II, através da eficiência fotossintética de Panicum maximum em pós-emergência. O ensaio foi constituído de seis tratamentos: hexazinone (250 g ha-1, tebuthiuron (1,0 kg ha-1, hexazinone + tebuthiuron (125 g ha-1 + 0,5 kg ha-1, diuron (2.400 g ha-1, hexazinone + diuron (125 + 1.200 g ha-1, metribuzin (1.440 g ha-1, hexazinone + metribuzin (125 + 720 g ha-1 e uma testemunha. O experimento foi instalado em delineamento inteiramente casualizado, com quatro repetições. Após a aplicação dos tratamentos, as plantas foram transportadas para casa de vegetação sob condições controladas de temperatura e umidade, onde ficaram durante o período experimental, sendo realizadas as seguintes avaliações: taxa de transporte de elétrons e análise visual de intoxicação. A avaliação com o fluorômetro foi realizada nos intervalos de 1, 2, 6, 24, 48, 72, 120 e 168 horas após a aplicação, e as avaliações visuais, aos três e sete dias após a aplicação. Os resultados demonstraram diferença nos tratamentos, enfatizando a aplicação do diuron, que reduziu lentamente o transporte de elétrons comparado com os outros herbicidas e, em mistura com hexazinone, apresentou efeito sinérgico. Verificou-se com o uso do fluorômetro a intoxicação antecipada em plantas de P. maximum após a aplicação de herbicidas inibidores do fotossistema II de forma isolada e em mistura.This work aimed to evaluate the speed and intensity of action of hexazinone applied alone and in combination with other photo-system II inhibitors on the photosynthetic efficiency of Panicum maximum in post-emergence. The assay consisted of six treatments: hexazinone (250 g ha-1, tebuthiuron (1.0 kg ha-1, hexazinone + tebuthiuron (125 g ha-1+ 0.5 kg ha-1, diuron (2,400 g ha-1, hexazinone + diuron (125 + 1,200 g ha-1, metribuzin
Structural Load Alleviation Applied to Next Generation Aircraft and Wind Turbines
Frost, Susan
2011-01-01
Reducing the environmental impact of aviation is a goal of the Subsonic Fixed Wing Project under the Fundamental Aeronautics Program of NASAs Aeronautics Research Mission Directorate. Environmental impact of aviation is being addressed by novel aircraft configurations and materials that reduce aircraft weight and increase aerodynamic efficiency. NASA is developing tools to address the challenges of increased airframe flexibility created by wings constructed with reduced structural material and novel light-weight materials. This talk will present a framework and demonstration of a flight control system using optimal control allocation with structural load feedback and constraints to achieve safe aircraft operation. As wind turbines age, they become susceptible to many forms of blade degradation. Results will be presented on work in progress that uses adaptive contingency control for load mitigation in a wind turbine simulation with blade damage progression modeled.
Feasibility of Applying Active Lubrication to Dynamically Loaded Fluid Film Bearings
Estupinan, Edgar Alberto; Santos, Ilmar
2009-01-01
The feasibility of modifying the dynamics of the thin fluid films of dynamically loaded journal bearings, using different strategies of active lubrication is studied in this work. A significant reduction in the vibration levels, wear and power friction losses, is expected. Particularly, the focus...... of this study is on the analysis of main crankshaft bearings, where the conventional hydrodynamic lubrication is modified by injecting oil at actively controllable pressures, through orifices circumferentially located along the bearing surface....
Alexander, C. S.; Ding, J. L.; Asay, J. R.
2016-03-01
Magnetically applied pressure-shear (MAPS) is a new experimental technique that provides a platform for direct measurement of material strength at extreme pressures. The technique employs an imposed quasi-static magnetic field and a pulsed power generator that produces an intense current on a planar driver panel, which in turn generates high amplitude magnetically induced longitudinal compression and transverse shear waves into a planar sample mounted on the drive panel. In order to apply sufficiently high shear traction to the test sample, a high strength material must be used for the drive panel. Molybdenum is a potential driver material for the MAPS experiment because of its high yield strength and sufficient electrical conductivity. To properly interpret the results and gain useful information from the experiments, it is critical to have a good understanding and a predictive capability of the mechanical response of the driver. In this work, the inelastic behavior of molybdenum under uniaxial compression and biaxial compression-shear ramp loading conditions is experimentally characterized. It is observed that an imposed uniaxial magnetic field ramped to approximately 10 T through a period of approximately 2500 μs and held near the peak for about 250 μs before being tested appears to anneal the molybdenum panel. In order to provide a physical basis for model development, a general theoretical framework that incorporates electromagnetic loading and the coupling between the imposed field and the inelasticity of molybdenum was developed. Based on this framework, a multi-axial continuum model for molybdenum under electromagnetic loading is presented. The model reasonably captures all of the material characteristics displayed by the experimental data obtained from various experimental configurations. In addition, data generated from shear loading provide invaluable information not only for validating but also for guiding the development of the material model for
Healing efficiency of shape memory polyurethane fiber reinforced syntactic foam under applied load
Ogunmekan, Babatunde
Shape memory composite materials have received a great deal of interest in recent structural developments, both in sandwich and in lightweight structures. Experimental procedures involving the free body healing of these materials have been carried out; however, it is important to investigate the healing behaviors of these SMP materials while under load. In this study, syntactic foams reinforced with strain-hardened short-shape memory polyurethane fibers (SMPUFs) were prepared to evaluate their ability to heal wide-opened cracks using the two-step biomimetic close-then-heal (CTH) self-healing scheme while under varying loads. The syntactic foam samples manufactured consisted of an epoxy matrix with dispersed thermoplastic particles, glass microballoons and short SMPUFs. The SMPUF strands were cold-drawn (stretched-then-released) for up to four cycles and then cut to 10 mm short fibers before casting the polymer matrix. Three types of syntactic foam specimens, consisting of 5%, 10%, and 15% thermoplastic particle volume fraction compositions, respectively, were manufactured, and notched beam samples were then prepared. Fracture-healing by uniaxial tension was conducted for five cycles on each sample. Material characterization techniques, such as scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), were utilized to highlight the crack healing characteristics and thermal properties. In addition, a high-resolution charge-coupled device (CCD) camera with a resolution of 3.7 x 3.7 μm/pixel was used to capture the crack tip opening displacement (CTOD). It is seen that the healing ability of the composite varies with changes in both the load carried and the volume fraction of thermoplastic particles. As the thermoplastic volume fraction increased from 5% to 10% to 15%, the tensile strength values recorded decreased, but there was also an increase in the healing efficiency. Moreover, SEM images revealed partial healing in samples with lower
Loturco, I; Nakamura, F Y; Kobal, R; Gil, S; Pivetti, B; Pereira, L A; Roschel, H
2016-12-01
It is unknown whether traditional periodization of strength-power training involving accumulation, transformation and realization blocks is superior to other simpler and more practical training schemes. The purpose of this study was thus to investigate changes in strength/power/speed characteristics of elite soccer players in response to either classic strength-power periodization (TSP) or optimum power load (OPL). 23 professional soccer players were randomly assigned to TSP or OPL for 6 weeks in-season regular training (3 times per week). TSP involved half squats or jump squats, depending on the respective training block, while OPL involved only jump squats at the optimum power load. Results revealed that both groups presented similar significant (Psuperior effect of OPL to improve 10- and 20-m speed. Similarly, OPL presented greater delta change in mean propulsive power in the jump squat. Therefore, training continuously at the optimum power zone resulted in superior performance improvements compared to training under classic strength-power periodization. © Georg Thieme Verlag KG Stuttgart · New York.
Dascalescu, A. E.; Lazaroiu, G.; Scupi, A. A.; Oanta, E.
2016-08-01
The rotating half-bridge of a settling tank is employed to sweep the sludge from the wastewater and to vacuum and sent it to the central collector. It has a complex geometry but the main beam may be considered a slender bar loaded by the following category of forces: concentrated forces produced by the weight of the scrapping system of blades, suction pipes, local sludge collecting chamber, plus the sludge in the horizontal sludge transporting pipes; forces produced by the access bridge; buoyant forces produced by the floating barrels according to Archimedes’ principle; distributed forces produced by the weight of the main bridge; hydrodynamic forces. In order to evaluate the hydrodynamic loads we have conceived a numerical model based on the finite volume method, using the ANSYS-Fluent software. To model the flow we used the equations of Reynolds Averaged Navier-Stokes (RANS) for liquids together with Volume of Fluid model (VOF) for multiphase flows. For turbulent model k-epsilon we used the equation for turbulent kinetic energy k and dissipation epsilon. These results will be used to increase the accuracy of the loads’ sub-model in the theoretical models, e. the finite element model and the analytical model.
Gupta, V K; Eggleton, C D
2011-07-01
Receptor-ligand interactions that mediate cellular adhesion are often subjected to forces that regulate their detachment via modulating off-rates. Although the dynamics of detachment is primarily controlled by the physical chemistry of adhesion molecules, cellular features such as cell deformability and microvillus viscoelasticity have been shown to affect the rolling velocity of leukocytes in vitro through experiments and simulation. In this work, we demonstrate via various micromechanical models of two cells adhered by a single (intramolecular) bond that cell deformability and microvillus viscoelasticity modulate transmission of an applied external load to an intramolecular bond, and thus the dynamics of detachment. Specifically, it is demonstrated that the intermolecular bond force is not equivalent to the instantaneous applied force and that the instantaneous bond force decreases with cellular and microvillus compliance. As cellular compliance increases, not only does the time lag between the applied load and the bond force increase, an initial response time is observed during which cell deformation is observed without transfer of force to the bond. It is further demonstrated that following tether formation the instantaneous intramoleular bond force increases linearly at a rate dependent on microvillus viscosity. Monte Carlo simulations with fixed kinetic parameters predict that both cell and microvillus compliance increase the average rupture time, although the average rupture force based on bond length remains nearly unchanged.
Oanta, Emil M.; Dascalescu, Anca-Elena; Sabau, Adrian
2016-12-01
The paper presents an original analytical model of the hydrodynamic loads applied on the half-bridge of a circular settling tank. The calculus domain is defined using analytical geometry and the calculus of the local dynamic pressure is based on the radius from the center of the settling tank to the current area, i.e. the relative velocity of the fluid and the depth where the current area is located, i.e. the density of the fluid. Calculus of the local drag forces uses the discrete frontal cross sectional areas of the submerged structure in contact with the fluid. In the last stage is performed the reduction of the local drag forces in the appropriate points belonging to the main beam. This class of loads is producing the flexure of the main beam in a horizontal plane and additional twisting moments along this structure. Taking into account the hydrodynamic loads, the results of the theoretical models, i.e. the analytical model and the finite element model, may have an increased accuracy.
Peleshko, V. A.
2016-06-01
The deviator constitutive relation of the proposed theory of plasticity has a three-term form (the stress, stress rate, and strain rate vectors formed from the deviators are collinear) and, in the specialized (applied) version, in addition to the simple loading function, contains four dimensionless constants of the material determined from experiments along a two-link strain trajectory with an orthogonal break. The proposed simple mechanism is used to calculate the constants of themodel for four metallic materials that significantly differ in the composition and in the mechanical properties; the obtained constants do not deviate much from their average values (over the four materials). The latter are taken as universal constants in the engineering version of the model, which thus requires only one basic experiment, i. e., a simple loading test. If the material exhibits the strengthening property in cyclic circular deformation, then the model contains an additional constant determined from the experiment along a strain trajectory of this type. (In the engineering version of the model, the cyclic strengthening effect is not taken into account, which imposes a certain upper bound on the difference between the length of the strain trajectory arc and the module of the strain vector.) We present the results of model verification using the experimental data available in the literature about the combined loading along two- and multi-link strain trajectories with various lengths of links and angles of breaks, with plane curvilinear segments of various constant and variable curvature, and with three-dimensional helical segments of various curvature and twist. (All in all, we use more than 80 strain programs; the materials are low- andmedium-carbon steels, brass, and stainless steel.) These results prove that the model can be used to describe the process of arbitrary active (in the sense of nonnegative capacity of the shear) combine loading and final unloading of originally
波浪作用下可液化海床最大液化深度%The maximum liquefaction depth of liquefiable seabed under wave loading
黄光爵; 郑永来; 武伯弢
2012-01-01
Large wave will cause liquefaction of seabed, and wave-induced liquefaction of seabed is a key problem of coastal and offshore engineering. Based on the Biot' s theory of consolidation, taking account of both the criteria of liquefaction of oscillatory and residual pore pressures, the analytical solution of the maximum depth of porous sandy seabed under wave loading is derived in this study. With the new expression and the FLAC numerical simulation, an example is calculated, and the results are almost the same. The results of FLAC simulation show that the pore water pressure begins to build up and the effective stress of seabed goes down,when the wave force is loaded. When the effective stress reaches zero, the sediment is liquefied. Then the sediment grains are rearranged and compacted. Later,the residual pore pressure is dissipated, and the effective stress comes to rise. At last, the analytical solution and the numerical calculation are compared for various wave heights, wave lengths and water depths, and the outcomes are about the same, reflecting the regularity well of the liquefaction depth of seabed.%较大的风浪会使海床发生液化,波浪引起的海床液化问题是海岸及近海工程必须考虑的关键问题之一.基于Biot固结理论,同时考虑了振荡孔隙水压力和残余孔隙水压力的液化准则,作者推出了波浪作用下可液化海床最大液化深度的解析表达式.同时分别采用解析表达式和FLAC数值模拟求解了相应的例子,两者得出的液化深度均和例子的基本相等.且从FLAC的结果可看出,加载波浪力时孔隙水压力开始累积,土体有效应力逐渐下降,当有效应力降到零时,海床土层液化,海床土颗粒重组后下沉压实,之后残余孔隙水压力开始消散,土层有效应力逐渐恢复.最后还就不同波高、波长和水深进行了解析解和数值解的对比,两者得出的结果比较吻合,并能较好地反映海床液化深度变化规律.
Vasile Cojocaru
2016-12-01
Full Text Available Several methods can be used in the FEM studies to apply the loads on a plain bearing. The paper presents a comparative analysis of maximum stress obtained for three loading scenarios: resultant force applied on the shaft – bearing assembly, variable pressure with sinusoidal distribution applied on the bearing surface, variable pressure with parabolic distribution applied on the bearing surface.
Zimmerman, Marc J.; Qian, Yu; Yong Q., Tian
2011-01-01
In 2004, the Total Maximum Daily Load (TMDL) for Total Phosphorus in the Assabet River, Massachusetts, was approved by the U.S. Environmental Protection Agency. The goal of the TMDL was to decrease the concentrations of the nutrient phosphorus to mitigate some of the instream ecological effects of eutrophication on the river; these effects were, for the most part, direct consequences of the excessive growth of aquatic macrophytes. The primary instrument effecting lower concentrations of phosphorus was to be strict control of phosphorus releases from four major wastewatertreatment plants in Westborough, Marlborough, Hudson, and Maynard, Massachusetts. The improvements to be achieved from implementing this control were lower concentrations of total and dissolved phosphorus in the river, a 50-percent reduction in aquatic-plant biomass, a 30-percent reduction in episodes of dissolved oxygen supersaturation, no low-flow dissolved oxygen concentrations less than 5.0 milligrams per liter, and a 90-percent reduction in sediment releases of phosphorus to the overlying water. In 2007, the U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, initiated studies to evaluate conditions in the Assabet River prior to the upgrading of wastewater-treatment plants to remove more phosphorus from their effluents. The studies, completed in 2008, implemented a visual monitoring plan to evaluate the extent and biomass of the floating macrophyte Lemna minor (commonly known as lesser duckweed) in five impoundments and evaluated the potential for phosphorus flux from sediments in impounded and free-flowing reaches of the river. Hydrologically, the two study years 2007 and 2008 were quite different. In 2007, summer streamflows, although low, were higher than average, and in 2008, the flows were generally higher than in 2007. Visually, the effects of these streamflow differences on the distribution of Lemna were obvious. In 2007, large amounts of
Warren, M. A.; Quartly, G. D.; Shutler, J. D.; Miller, P. I.; Yoshikawa, Y.
2016-09-01
Attempts to automatically estimate surface current velocities from satellite-derived thermal or visible imagery face the limitations of data occlusion due to cloud cover, the complex evolution of features and the degradation of their surface signature. The Geostationary Ocean Color Imager (GOCI) provides a chance to reappraise such techniques due to its multiyear record of hourly high-resolution visible spectrum data. Here we present the results of applying a Maximum Cross Correlation (MCC) technique to GOCI data. Using a combination of simulated and real data we derive suitable processing parameters and examine the robustness of different satellite products, those being water-leaving radiance and chlorophyll concentration. These estimates of surface currents are evaluated using High Frequency (HF) radar systems located in the Tsushima (Korea) Strait. We show the performance of the MCC approach varies depending on the amount of missing data and the presence of strong optical contrasts. Using simulated data it was found that patchy cloud cover occupying 25% of the image pair reduces the number of vectors by 20% compared to using perfect images. Root mean square errors between the MCC and HF radar velocities are of the order of 20 cm s-1. Performance varies depending on the wavelength of the data with the blue-green products out-performing the red and near infra-red products. Application of MCC to GOCI chlorophyll data results in similar performance to radiances in the blue-green bands. The technique has been demonstrated using specific examples of an eddy feature and tidal induced features in the region.
Doroshenko Sergey Aleksandrovich
2012-10-01
Full Text Available The authors discuss wind loads applied to a set of two buildings. The wind load is simulated with the help of the wind tunnel. In the Russian Federation, special attention is driven to the aerodynamics of high-rise buildings and structures. According to the Russian norms, identification of aerodynamic coefficients for high-rise buildings, as well as the influence of adjacent buildings and structures, is performed on the basis of models of structures exposed to wind impacts simulated in the wind tunnel. This article deals with the results of the wind tunnel test of buildings. The simulation was carried out with the involvement of a model of two twenty-three storied buildings. The experiment was held in a wind tunnel of the closed type at in the Institute of Mechanics of Moscow State University. Data were compared at the zero speed before and after the experiment. LabView software was used to process the output data. Graphs and tables were developed in the Microsoft Excel package. GoogleSketchUp software was used as a visualization tool. The three-dimensional flow formed in the wind tunnel can't be adequately described by solving the two-dimensional problem. The aerodynamic experiment technique is used to analyze the results for eighteen angles of the wind attack.
Guan, Yajing; Cui, Huawei; Ma, Wenguang; Zheng, Yunye; Tian, Yixin; Hu, Jin
2014-01-01
Drought is one of the most important stress factors limiting the seed industry and crop production. Present study was undertaken to create novel drought-resistant pelleted seeds using the combined materials with superabsorbent polymer, poly(2-acrylamide-2-methyl propane sulfonic acid) (PAMPS) hydrogel, and drought resistance agent, salicylic acid (SA). The optimized PAMPS hydrogel was obtained as the molar ratio of 2-acrylamido-2-methyl-propanesulfonic acid (AMPS) to potassium peroxydisulfate (KPS) and N, N'-methylene-bis-acrylamide (MBA) was 1 : 0.00046 : 0.00134. The hydrogel weight after swelling in deionized water for 24 h reached 4306 times its own dry weight. The water retention ratio (RR) of PAMPS was significantly higher as compared with the control. It could keep as high as 85.3% of original weight after 30 min at 110 °C; even at 25 °C for 40 d, the PAMPS still kept RR at 33.67%. PAMPS disintegration ratio increased gradually and reached around 30% after embedding in soil or activated sludge for 60 d. In addition, there were better seed germination performance and seedling growth in the pelleted treatments with SA-loaded PAMPS hydrogel under drought stress than control. It suggested that SA-loaded PAMPS hydrogel, a nontoxic superabsorbent polymer, could be used as an effective drought resistance material applied to tobacco pelleted seeds.
Yajing Guan
2014-01-01
Full Text Available Drought is one of the most important stress factors limiting the seed industry and crop production. Present study was undertaken to create novel drought-resistant pelleted seeds using the combined materials with superabsorbent polymer, poly(2-acrylamide-2-methyl propane sulfonic acid (PAMPS hydrogel, and drought resistance agent, salicylic acid (SA. The optimized PAMPS hydrogel was obtained as the molar ratio of 2-acrylamido-2-methyl-propanesulfonic acid (AMPS to potassium peroxydisulfate (KPS and N, N′-methylene-bis-acrylamide (MBA was 1 : 0.00046 : 0.00134. The hydrogel weight after swelling in deionized water for 24 h reached 4306 times its own dry weight. The water retention ratio (RR of PAMPS was significantly higher as compared with the control. It could keep as high as 85.3% of original weight after 30 min at 110°C; even at 25°C for 40 d, the PAMPS still kept RR at 33.67%. PAMPS disintegration ratio increased gradually and reached around 30% after embedding in soil or activated sludge for 60 d. In addition, there were better seed germination performance and seedling growth in the pelleted treatments with SA-loaded PAMPS hydrogel under drought stress than control. It suggested that SA-loaded PAMPS hydrogel, a nontoxic superabsorbent polymer, could be used as an effective drought resistance material applied to tobacco pelleted seeds.
Frantiescoli A. Dimer
2014-01-01
Full Text Available In spite of different methods reported in the literature to determine olanzapine in biological fluids, all of them used high volumes of plasma. Therefore, the purpose of this paper was to develop an LC-MS/MS method using small plasma volume (0.1 mL to apply in a preclinical pharmacokinetic investigation. The method was linear over the concentration ranges of 10 - 1000 ng mL-1. Extraction recoveries, stability, and validation parameters were evaluated. Results were within the acceptable limits of international guidelines. A significant decrease in clearance led to a significant 2.26-times increase in AUC0 - 6h of olanzapine-loaded lipid-core nanocapsules compared with free-olanzapine.
Marouane El Azzaoui
2016-07-01
Full Text Available The vector control performance applied to rotating machines depends largely on static and dynamic characteristics of the inverter associated with it. The development of the pulse-width modulation (PWM provided greater flexibility in the control of the converters. The objective of this work is to construct a simplified and practical space vector modulation (SVM based on the selection of the sequence and the calculation of the conduction time or extinction. We have presented the blocks of the simulation vector modulation on the Matlab / Simulink with a new method for determining conduction time and analyzed its application on a load RL supplied by a voltage inverter. The performance of the proposed method has been presented by the simulation results.
Leucci, Giovanni; Vasanelli, Emilia; Calia, Angela; Micelli, Francesco; Aiello, Maria Antonietta
2014-05-01
Sophisticated non destructive techniques for the diagnosis of existing masonry structures have been developed and improved throughout the years, such as ground penetrating radar, thermography, sonic and ultrasonic tomography, laser scanner survey, etc.: by using an integrated approach it is possible to reconstruct the morphology of the masonry walls, to detect the presence of cracks and voids, achieving an accurate and reliable diagnosis of the construction, which is the basis for the restoration design. The ultrasonic pulse velocity (UPV) method can be conveniently used to check the quality of stones, but it can be used also for material characterization. Both the intrinsic characteristic of the stone (porosity, grain size, anisotropy, etc.) and the external factors (humidity, stress, temperature, presence of cracks) may affect the elastic wave propagation, thus in order to correctly estimate the ultrasonic behaviour of the material investigated it is important to know in what manner and how much the variation of the experimental conditions may modify the characteristics of the waves being measured. This aspect is of crucial importance when in situ measurements are made. In this work the influence of the applied load on UPV results has been investigated. In particular, the research has been carried out on ashlars and on sample masonry panels made of lime mortar joints and Lecce stone, a soft calcarenitic stone traditionally used in the Lecce district, South of Italy. The presence of load strongly influenced the UPV measures, due to the particular microstructural characteristic of the stone. The work aim at quantify this influence in order to correctly interpret in situ measurements.
Kennen, Jonathan G.; Riskin, Melissa L.; Reilly, Pamela A.; Colarullo, Susan J.
2013-01-01
More than 300 ambient monitoring sites in New Jersey have been identified by the New Jersey Department of Environmental Protection (NJDEP) in its integrated water-quality monitoring and assessment report (that is, the 305(b) Report on general water quality and 303(d) List of waters that do not support their designated uses) as being impaired with respect to aquatic life; however, no unambiguous stressors (for example, nutrients or bacteria) have been identified. Because of the indeterminate nature of the broad range of possible impairments, surrogate measures that more holistically encapsulate the full suite of potential environmental stressors need to be developed. Streamflow alteration resulting from anthropogenic changes in the landscape is one such surrogate. For example, increases in impervious surface cover (ISC) commonly cause increases in surface runoff, which can result in “flashy” hydrology and other changes in the stream corridor that are associated with streamflow alteration. The NJDEP has indicated that methodologies to support a hydrologically based Total Maximum Daily Load (hydro-TMDL) need to be developed in order to identify hydrologic targets that represent a minimal percent deviation from a baseline condition (“minimally altered”) as a surrogate measure to meet criteria in support of designated uses. The primary objective of this study was to develop an applicable hydro-TMDL approach to address aquatic-life impairments associated with hydrologic alteration for New Jersey streams. The U.S. Geological Survey, in cooperation with the NJDEP, identified 51 non- to moderately impaired gaged streamflow sites in the Raritan River Basin for evaluation. Quantile regression (QR) analysis was used to compare flow and precipitation records and identify baseline hydrographs at 37 of these sites. At sites without an appropriately long period of record (POR) or where a baseline hydrograph could not be identified with QR, a rainfall-runoff model was used
Selinder, Patrik [ZW Energiteknik, Nykoeping (Sweden)
2005-11-01
The energy used in Swedish district heating networks is primarily used for heating purposes in buildings, whereas the energy used for heating the domestic hot water is a minor part - about 10 to 20 % - of the total energy used in district heating systems. However, as the involved heat capacity is concerned, both heating of hot water and heating of buildings are very often of comparable sizes. Although effect of simultaneity of hot water consumption reduces the total hot water heating capacity in the built environment, the behaviour pattern of the customers is such that the hot water use results in high hot water loads for a given building at certain hours of a day. The preparation of domestic hot water therefore makes large demands on the heating capacity of the district heating net in relation to the ability of repayment due to the energy consumption. However, a building exhibits in general a good possibility for decreasing the total heat load by involving its thermal mass and therefore borrowing under limited time a part of its house heating capacity for hot water heating purposes. The thermal mass of the building ensures that this 'capacity-borrowing' is not experienced as a decrease in comfort. The goal of this project was to develop and to test a control algorithm acting on the control system of a customer substation with the purpose of temporarily reduce the heat delivery when high hot water demands occur. This algorithm has then been tested in a residential building in Goeteborg, Sweden. The control principle was applied on a Swedish customer substation with two heat exchangers connected in parallel for both radiator heating and instantaneous domestic hot water preparation. The basic idea was to reduce the opening angle of the radiator valve when a larger demand of hot water occurs (indicated by opening of the hot water control valve). A control algorithm based on certain physical parameters calculates in this case the closing angle of the radiator
Anon [Dept. of Mechanical Design Engieering, Andong National University, Andong (Korea, Republic of); Anon [Dept. of Engineering, Aurora State College of Technology, Baler (Philippines)
2014-12-15
REBCO coated conductor (CC) tapes with superior mechanical and electromechanical properties are preferable in applications such as superconducting coils and magnets. The CC tapes should withstand factors that can affect their performance during fabrication and operation of its applications. In coil applications, CC tapes experience different mechanical constraints such as tensile or compressive stresses. Recently, the critical current (I{sub c}) degradation of CC tapes used in coil applications due to delamination were already reported. Thermal cycling, coefficient of thermal expansion mismatch among constituent layers, screening current, etc. can induce excessive transverse tensile stresses that might lead to the degradation of I{sub c} in the CC tapes. Also, CC tapes might be subjected to very high magnetic fields that induce strong Lorentz force which possibly affects its performance in coil applications. Hence, investigation on the delamination mechanism of the CC tapes is very important in coiling, cooling, operation and design of prospect applications. In this study, the electromechanical properties of REBCO CC tapes fabricated by reactive co-evaporation by deposition and reaction (RCE-DR) under transversely applied loading were investigated. Delamination strength of the CC tape was determined using the anvil test. The I{sub c} degraded earlier under transverse tensile stress as compared to that under compressive one.
Ahumada, Ramón; Vargas, José; Pagliero, Liliana
2006-07-01
San Vicente Bay is a coastal shallow embayment in Central Chile with multiple uses, one of which is receiving wastewater from industrial fisheries, steel mill effluents, and domestic sewage. A simulation model was developed and applied to dissolved oxygen consumption by organic residues released into this embayment. Three compartments were established as function of: depth, circulation and outfall location. The model compartments had different volumes, and their oxygen saturation value was used as baseline. The parameters: (a) BOD5 of the industrial and urban effluents, (b) oxygen demand by organic sediments, (c) respiration, (d) photosynthesis and (e) re-aeration were included in the model. Iteration results of the model showed severe alterations in Compartment 1, with a decrease of 65% in the oxygen below saturation. Compartment 2 showed a small decline (10%) and compartment 3 did not show apparent changes in oxygen values. Measures recommended for remediation were to decrease the BOD5 loading by 30% in the affected sector. Iteration of the model for 200 h following recommendations derived from the preceding results produced an increase in saturation of 60% (5 ml O2 L(-1)), which suggested an improvement of the environmental conditions.
AnSBBR applied to the treatment of metalworking fluid wastewater: effect of organic and shock load.
Carvalhinha, Pedro P; Flôres, Anderson; Rodrigues, José A D; Ratusznei, Suzana M; Zaiat, Marcelo; Foresti, Eugenio
2010-11-01
An investigation was performed regarding the application of a mechanically stirred anaerobic sequencing batch biofilm reactor containing immobilized biomass on inert polyurethane foam (AnSBBR) to the treatment of soluble metalworking fluids to remove organic matter and produce methane. The effect of increasing organic matter and reactor fill time, as well as shock load, on reactor stability and efficiency have been analyzed. The 5-L AnSBBR was operated at 30 degrees C in 8-h cycles, agitation of 400 rpm, and treated 2.0 L effluent per cycle. Organic matter was increased by increasing the influent concentration (500, 1,000, 2,000, and 3,000 mg chemical oxygen demand (COD)/L). Fill times investigated were in the batch mode (fill time 10 min) and fed-batch followed by batch (fill time 4 h). In the batch mode, organic matter removal efficiencies were 87%, 86%, and 80% for influent concentrations of 500, 1,000, and 2,000 mgCOD/L (1.50, 3.12, and 6.08 gCOD/L.d), respectively. At 3,000 mgCOD/L (9.38 gCOD/L.d), operational stability could not be achieved. The reactor managed to maintain stability when a shock load twice as high the feed concentration was applied, evidencing the robustness of the reactor to potential concentration variations in the wastewater being treated. Increasing the fill time to 4 h did not improve removal efficiency, which was 72% for 2,000 mgCOD/L. Thus, gradual feeding did not improve organic matter removal. The concentration of methane formed at 6.08 gCOD/L was 5.20 mmolCH(4), which corresponded to 78% of the biogas composition. The behavior of the reactor during batch and fed-batch feeding could be explained by a kinetic model that considers organic matter consumption, production, and consumption of total volatile acids and methane production.
Sterling Nesbitt
2015-04-01
Full Text Available We determined inhomogeneity of strains around discontinuities as well as changes in orientation of collagen fibrils under applied load in skin. Second Harmonic Generation (SHG images of collagen fibrils were obtained at different strain magnitudes. Changes in collagen orientation were analyzed using Fast Fourier Transforms (FFT while strain inhomogeneity was determined at different distances from hair follicles using Digital Image Correlation (DIC. A parameter, defined as the Collagen Orientation Index (COI, is introduced that accounts for the increasingly ellipsoidal nature of the FFT amplitude images upon loading. We show that the COI demonstrates two distinct mechanical regimes, one at low strains (0%, 2.5%, 5% strain in which randomly oriented collagen fibrils align in the direction of applied deformation. In the second regime, beginning at 5% strain, collagen fibrils elongate in response to applied deformation. Furthermore, the COI is also found to be linearly correlated with the applied stress indicating that collagen fibrils orient to take the applied load. DIC results indicated that major principal strains were found to increase with increased load at all locations. In contrast, minimum principal strain was dependent on distance from hair follicles. These findings are significant because global and local changes in collagen deformations are expected to be changed by disease, and could affect stem cell populations surrounding hair follicles, including mesenchymal stem cells within the outer root sheath.
Laben, J K; Dodd, D; Sneed, L
1991-01-01
Group psychotherapy has been considered the treatment of choice by many therapists working with offenders within the criminal justice system. However, there has been little written by nurses regarding this special population. This article's purpose is to illustrate how King's theory of goal attainment may be used in conducting group psychotherapy with offender populations. The application of King's model is demonstrated in three milieus: an inpatient setting for juvenile sexual offenders, a state maximum security prison, and a halfway house for offenders involved in a work-release program. The methodology and use of visual aids in actualizing King's theory of mutual goal setting and goal attainment are discussed.
Wit, de M.
2000-01-01
In many European rivers, including the major streams of the Rhine and Elbe basins, the nutrient load (N and P) still exceeds target levels. In this paper, a model is presented that describes the river nutrient load as a function of nutrient sources, runoff and lithology in the upstream basin. The mo
Kinkhabwala, Ali
2013-01-01
The most fundamental problem in statistics is the inference of an unknown probability distribution from a finite number of samples. For a specific observed data set, answers to the following questions would be desirable: (1) Estimation: Which candidate distribution provides the best fit to the observed data?, (2) Goodness-of-fit: How concordant is this distribution with the observed data?, and (3) Uncertainty: How concordant are other candidate distributions with the observed data? A simple unified approach for univariate data that addresses these traditionally distinct statistical notions is presented called "maximum fidelity". Maximum fidelity is a strict frequentist approach that is fundamentally based on model concordance with the observed data. The fidelity statistic is a general information measure based on the coordinate-independent cumulative distribution and critical yet previously neglected symmetry considerations. An approximation for the null distribution of the fidelity allows its direct conversi...
Britton, Andrea J., E-mail: a.britton@macaulay.ac.u [Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen AB15 8QH (United Kingdom); Fisher, Julia M. [Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen AB15 8QH (United Kingdom)
2010-05-15
The influence of applied nitrogen (N) concentration and load on thallus chemistry and growth of five terricolous alpine lichen species was investigated in a three-month N addition study. Thallus N content was influenced by both concentration and load; but the relative importance of these parameters varied between species. Growth was most affected by concentration. Thresholds for effects observed in this study support a low critical load for terricolous lichen communities (<7.5 kg N ha{sup -1} y{sup -1}) and suggest that concentrations of N currently encountered in UK cloudwater may have detrimental effects on the growth of sensitive species. The significance of N concentration effects on sensitive species also highlights the need to avoid artificially high concentrations when designing N addition experiments. Given the sensitivity of some species to extremely low loads and concentrations of N we suggest that terricolous lichens have potential as indicators of deposition and impact in northern and alpine ecosystems. - Terricolous lichen species' N content responds to both applied N concentration and load while applied N concentration has greatest effects on growth.
Izumi, Kenji; Bartlein, Patrick J.
2016-10-01
The inverse modeling through iterative forward modeling (IMIFM) approach was used to reconstruct Last Glacial Maximum (LGM) climates from North American fossil pollen data. The approach was validated using modern pollen data and observed climate data. While the large-scale LGM temperature IMIFM reconstructions are similar to those calculated using conventional statistical approaches, the reconstructions of moisture variables differ between the two approaches. We used two vegetation models, BIOME4 and BIOME5-beta, with the IMIFM approach to evaluate the effects on the LGM climate reconstruction of differences in water use efficiency, carbon use efficiency, and atmospheric CO2 concentrations. Although lower atmospheric CO2 concentrations influence pollen-based LGM moisture reconstructions, they do not significantly affect temperature reconstructions over most of North America. This study implies that the LGM climate was very cold but not very much drier than present over North America, which is inconsistent with previous studies.
Yulia V. Bondar
2012-03-01
Full Text Available The anatomical structure of the leaves of two Rhododendron L. species from the first and the second years of growing was investigated. Diagnostic features have been revealed, and that will allow further to more rational choice of specific structure planned in landscape gardening, and also to develop practical recommendations about cultivation of modeling species of this genus. Comparative- morphological method was applied.
Leonardo W. T. Silva
2014-08-01
Full Text Available In launching operations, Rocket Tracking Systems (RTS process the trajectory data obtained by radar sensors. In order to improve functionality and maintenance, radars can be upgraded by replacing antennas with parabolic reflectors (PRs with phased arrays (PAs. These arrays enable the electronic control of the radiation pattern by adjusting the signal supplied to each radiating element. However, in projects of phased array radars (PARs, the modeling of the problem is subject to various combinations of excitation signals producing a complex optimization problem. In this case, it is possible to calculate the problem solutions with optimization methods such as genetic algorithms (GAs. For this, the Genetic Algorithm with Maximum-Minimum Crossover (GA-MMC method was developed to control the radiation pattern of PAs. The GA-MMC uses a reconfigurable algorithm with multiple objectives, differentiated coding and a new crossover genetic operator. This operator has a different approach from the conventional one, because it performs the crossover of the fittest individuals with the least fit individuals in order to enhance the genetic diversity. Thus, GA-MMC was successful in more than 90% of the tests for each application, increased the fitness of the final population by more than 20% and reduced the premature convergence.
Fei, Tan; Yang, Lian-juan; Mo, Xiao-hui; Wang, Xiu-li; Jun, Gu
2014-11-01
Low-dose metronomic (LDM) chemotherapy with cytotoxic agents, aimed at disrupting tumor endothelial cells, is an alternative method to maximum tolerated dose chemotherapy targeting proliferating tumor cells in clinical practice. However, even in the LDM schedule, cytotoxic agents still exhibit serious side effects due to non-distribution and high accumulated doses in the body. Nanocarriers can maximize the efficacy of the encapsulated drug by adjusting the pharmacokinetics and bio-distribution pattern, and minimize excessive toxic side effects. In the present study, we prepared polyethylene glycol (PEG)-coated stealth nanoparticles containing paclitaxel (PTX-NP) in order to evaluate their accumulation in tumor and their anti-tumor activity following LDM administration. PTX-NPs were prepared by a modified emulsification/solvent diffusion method with methoxy PEG-poly(lactide). The in vitro viability, migration, and tube formation of primary human umbilical vein endothelial cells, in addition to thrombospondin-1 positive expression and microvessel density in vivo, confirmed the anti-angiogenic activity of PTX-NP. The cellular uptake and retention study, in addition to pharmacokinetics in Sprague-Dawley rats demonstrated sustained circulation of PTX-NP. The in vivo tumor accumulation of PTX-NP was monitored using the Xenogen IVIS 200 non-invasive optical imaging system. The anti-tumor activity of LDM PTX-NP was studied in B16 melanoma cancer-bearing mice in vivo. In conclusion, PTX-NP improved tumor accumulation and anti-tumor efficacy following LDM administration.
Zauner, C., E-mail: zauner@krp-m.de [KRP-Mechatec Engineering GbR, D-85748 Garching (Germany); Klammer, J. [KRP-Mechatec Engineering GbR, D-85748 Garching (Germany); Hartl, M.; Kampf, D. [Kayser-Threde GmbH, D-81379 Munich (Germany); Huber, A.; Mertens, Ph.; Schweer, B.; Terra, A. [Institute of Energy and Climate Research – Plasma Physics, Forschungszentrum Jülich, EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich (Germany); Balshaw, N. [Euratom-CCFE Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)
2013-10-15
Considering multi-physics requirements and loads in the early design phase as well as during the later experimental verification is especially important for the design of fusion devices due to the extreme environmental conditions and loads. Typical disciplines in design of fusion devices are thermodynamics, structural-mechanics, electro-magnetics, and optics. The interaction of these disciplines as well as an efficient approach to implement this interaction in numerical and experimental simulations is presented as applied at the new JET KL11 divertor endoscope design and verification process. The endoscope's first pictures already showed the very good performance of the instrument.
Dabrowski, James M
2014-07-01
Full Text Available , 2629–2643, 2014 www.hydrol-earth-syst-sci.net/18/2629/2014/ doi:10.5194/hess-18-2629-2014 © Author(s) 2014. CC Attribution 3.0 License. Applying SWAT to predict ortho-phosphate loads and trophic status in four reservoirs in the upper Olifants catchment... of sewage treatment works (STWs) are operating poorly and are likely an important source of bioavailable ortho- phosphate (OP) in the catchment. The Soil Water Assessment Tool (SWAT) was used to identify important sources of OP loading in the catchment...
黄建明; 吴春华; 徐坤; 付立
2012-01-01
The operation principle of photovoltaic optimizer system and the essence of maximum power point tracking (MPPT) are introduced. Each PV module adopts MPPT control algorithm in photovoltaic optimizer system, which leads to wrong judgment of the traditional MPPT method due to the load impedance perturbation. Based on the equivalent load impedance perturbation, the distributed maximum power point tracking (DMPPT) is proposed to solve the problem. Considering the disturbance of control variables and load impedance to track MPP, the interaction between individual modules in the photovoltaic optimizer system is avoided. Finally, comparative experiments prove that the DMPPT method based on the equivalent load impedance perturbation proposed in this paper has the advantage of quick response and perturbation resistance to load impedance. Furthermore, the stability of this method is better than conventional MPPT method.%介绍了光伏优化器系统的工作原理及最大功率点跟踪的本质.针对光伏优化器系统中每块光伏组件进行MPPT控制,造成传统MPPT方法由于负载阻抗扰动而引起误判断的问题,提出了一种基于等效负载阻抗扰动的分布式最大功率点跟踪方法.该方法综合考虑控制量扰动和负载阻抗扰动进行MPPT判断,避免光伏优化器系统中各个独立模块之间的相互影响.通过对比实验证明提出的基于等效负载阻抗扰动的最大功率点跟踪方法具有快速的响应能力及抗负载阻抗扰动能力,其稳定性优于传统的MPPT方法.
Huang-Pollock, Cynthia L.; Nigg, Joel T.; Carr, Thomas H.
2005-01-01
Background: Whether selective attention is a primary deficit in childhood Attention Deficit Hyperactivity Disorder (ADHD) remains in active debate. Methods: We used the "perceptual load" paradigm to examine both early and late selective attention in children with the Primarily Inattentive (ADHD-I) and Combined subtypes (ADHD-C) of ADHD. Results:…
The effect of applied stress on damage mode of 3D C/C composites under bend-bend fatigue loading
LIAO XiaoLing; LI HeJun; XU WenFeng; LI KeZhi
2007-01-01
The bend-bend fatigue behavior of 3D integral braided carbon/carbon composites (3D C/C) was examined. Fatigue test was conducted under load control at a sinusoidal frequency of 10 Hz to obtain stress-fracture cycles (S-N) relationship. The fatigue limit of the C/C was found to be 203 MPa (92% of the static flexural strength), the lag loops of fatigue load-displacement were transformed from elasticity to anelasticity and the flexibility of specimens were enhanced with increase in applied stress. It is revealed that the interfacial sliding abrasion played an important role in the fatigue failure process, and the extent and speed of sliding abrasion were controlled by the level of applied stress.
The effect of applied stress on damage mode of 3D C/C composites under bend-bend fatigue loading
2007-01-01
The bend-bend fatigue behavior of 3D integral braided carbon/carbon composites (3D C/C) was examined. Fatigue test was conducted under load control at a sinu-soidal frequency of 10 Hz to obtain stress-fracture cycles (S-N) relationship. The fatigue limit of the C/C was found to be 203 MPa (92% of the static flexural strength), the lag loops of fatigue load-displacement were transformed from elasticity to anelasticity and the flexibility of specimens were enhanced with increase in applied stress. It is revealed that the interfacial sliding abrasion played an important role in the fatigue failure process, and the extent and speed of sliding abrasion were con-trolled by the level of applied stress.
Fisher, J. A.; Berosik, S. R.; Lee, K.B.; Santhanam, S.
2007-01-01
We have investigated the effects of sample-loading solutions on sequencing performance on the Applied Biosystems 3730 DNA Analyzer, and in particular their effects on the decline of sequencing performance, or loss of resolution. We compared sequencing performance of samples resuspended in water, 0.1 mM EDTA, or deionized formamide. Our results show that samples resuspended in water give poorer overall performance in terms of average number of Q20 bases per sample and in the amount of variabil...
Zhuo, Yaobin; Zhou, Xiaojun; Yang, Chenlong
2014-11-01
In this paper, a three degrees of freedom (dof) model was established for a double-row self-aligning ball bearing (SABB) system, and was applied to study the dynamic behavior of the system during starting process and constant speed rotating process. A mathematical model was developed concerning stiffness and damping characteristics of the bearing, as well as three-dimensional applied load, rotor centrifugal force, etc. Balls and races were all considered as nonlinear springs, and the contact force between ball and race was calculated based on classic Hertzian elastic contact deformation theory and deformation compatibility theory. The changes of each ball's contact force and loaded angle of each row were taken into account. In order to solve the nonlinear dynamical equilibrium equations of the system, these equations were rewritten as differential equations and the fourth order Runge-Kutta method was used to solve the equations iteratively. In order to verify accuracy of the dynamical model and correctness of the numerical solution method, a kind of SABB-BRF30 was chosen for case studies. The effects of several important governing parameters, such as radial and axial applied loads, normal internal, inner and outer races waviness, and number of balls were investigated. These parametric studies led to a complete characterization of the shaft-bearing system vibration transmission. The research provided a theoretical reference for new type bearing design, shaft-bearing system kinetic analysis, optimal design, etc.
D. A. Santos
2014-09-01
Full Text Available An anaerobic sequencing batch biofilm reactor (AnSBBR containing immobilized biomass and operating with recirculation of the liquid phase (total liquid volume 4.5 L; treated volume per cycle 1.9 L was used to treat sucrose-based wastewater at 30 ºC and produce biohydrogen. The influence of applied volumetric organic load was studied by varying the influent concentration at 3600 and 5400 mgCOD.L-1 and using cycle lengths of 4, 3 and 2 hours, obtaining in this manner volumetric organic loads of 9, 12, 13.5, 18 and 27 gCOD.L-1.d-1. Different performance indicators were used: productivity and yield of biohydrogen per applied and removed load, reactor stability and efficiency based on the applied and removed organic loads, both in terms of organic matter (measured as COD and carbohydrate (sucrose. The results revealed system stability (32-37% of H2 in biogas during biohydrogen production, as well as substrate consumption (12-19% COD; 97-99% sucrose. Conversion efficiencies decreased when the influent concentration was increased (at constant cycle length and when cycle lengths were reduced (at constant influent concentrations. The best yield was 4.16 mol-H2.kg-SUC-1 (sucrose load at 9 gCOD.L-1.d-1 (3600 mgCOD.L-1 and 4 h with H2 content in the biogas of 36% (64% CO2 and 0% CH4. However, the best specific molar productivity of hydrogen was 8.5 molH2.kgTVS-1.d-1 (32% H2; 68% CO2; 0% CH4, at 18 gCOD.L-1.d-1 (5400 mgCOD.L-1 and 3 h, indicating that the best productivity tends to occur at higher organic loads, as this parameter involves the "biochemical generation" of biogas, whereas the best yield tends to occur at lower and/or intermediate organic loads, as this parameter involves "biochemical consumption" of the substrate. The most significant metabolites were ethanol, acetic acid and butyric acid. Microbiological analyses revealed that the biomass contained bacilli and endospore filaments and showed no significant variations in morphology between
Henschel Sebastian
2015-01-01
Full Text Available Dynamic crack initiation with crack-tip loading rates of K̇ ≈ 2.106MPa√ms-1 in a high strength G42CrMoS4 steel was investigated. To this end, a previously developed split Hopkinson pressure bar with four-point bending was utilised. V-notched and pre-cracked Charpy specimens were tested. The detection of dynamic crack initiation was performed by analysing the dynamic force equilibrium between the incident and the transmission bar. Additionally, the signal of a near-field strain gauge and high-speed photography were used to determine the instant of crack initiation. To account for vibrations of the sample, a dynamic analysis of the stress intensity factor was performed. The dynamic and static analyses of the tests produced nearly the same results when a force equilibrium was achieved. Fracture-surface analysis revealed that elongated MnS inclusions strongly affected both the dynamic crack initiation and growth. Blunting of the precrack did not take place when a group of MnS inclusions was located directly at the precrack tip. Due to the direction of the elongated MnS inclusions perpendicular to the direction of crack growth, the crack could be deflected. The comparison with a 42CrMo4 steel without elongated MnS inclusions revealed the detrimental effect in terms of resistance to crack initiation. Taking the loading-rate dependency into consideration, it was shown that there was no pronounced embrittlement due to the high loading rates.
S. ALI Al-MAWSAWI
2014-12-01
Full Text Available In this paper, a new developed steady-state model of the UPFC is proposed. The proposed model consists of one shunt compensation block and two series compensation blocks. In this case, the UPFC with the new model will be investigated when it is installed in multi-machine systems with non-linear load model. In addition, the steady–state performance of the new model operating as impedance compensation will be presented and compared with that obtained from the original Gyugyi model.
Santiago Correa Vélez
2013-03-01
teeth restored with prefabricated posts to maximum static intercuspidation loads, cyclical mastication loads and bruxism, and analyze the effect of periodontal loss on resistance by restorations. Methods: using the finite element method, an in vitro study was conducted of teeth with periodontal loss rehabilitated with prefabricated glass fiber, carbon and titanium posts. Reconstruction of the teeth was based on tomographic images from a periodontically healthy patient. Results: it was shown that rehabilitations did not tend to yield to static loads, irrespective of post material or the degree of periodontal loss. For bruxism and 4 mm periodontal loss, dentin durability was 60 000 cycles, irrespective of post material. For mastication loads and a healthy periodont, dentin failure occurs at 100 000 cycles with titanium posts, 200 000 cycles with carbon fiber posts, and 1 100 000 cycles with glass fiber posts. For 2 mm periodontal loss, dentin durability decreased to 4 000 cycles with titanium posts, 5 000 cycles with carbon fiber posts, and 7 000 cycles with glass fiber posts. For 4 mm periodontal loss, dentin durability is estimated at 1 000 cycles, irrespective of post material. Conclusions: restorations with glass fiber, carbon and titanium prefabricated posts do not yield to maximum static intercuspidation loads, irrespective of the degree of periodontal loss. Prefabricated posts exhibit endless resistance to cyclic loads. Dentin is the structure most severely affected by such events.
Dispersing Si{sub 3}N{sub 4} at high solids loading - applied to protein forming
Lyckfeldt, O.; Palmqvist, L. [Swedish Ceramic Inst., Goeteborg (Sweden); Poeydemenge, F. [ENSCI, Limoges (France)
2002-07-01
The dispersing of a Si{sub 3}N{sub 4} powder (UBE SN-E10) at high solids loading in aqueous media was investigated. The powder was used in the as-received (raw) state, after thermal (calcinations) and/or mechanical pre-treatments (ball milling{yields}freeze granulation{yields}freeze-drying). Slips were prepared using pH adjustment with NH{sub 4}OH or an addition of Tiron (low-M{sub w} sulphonic acid). Zeta potential measurements of diluted systems and rheological evaluations of concentrated suspensions were conducted. The effect of adding whey protein concentrate (WPC) was also studied. Zeta potential measurements showed a clear decrease in pH{sub iep} by calcination, whereas Tiron slightly increased the pH{sub iep} of calcined powder and decreased the pH{sub iep} of the as-received powder. Rheological data showed that pH adjustment to 10 was more efficient in stabilising the as-received powder than the calcined powder. pH adjustment was also considered to be the most important effect of adding small amounts of Tiron (0.08 wt%). However, for calcined powder, Tiron was shown to be equally efficient as pH adjustment. Pre-milling followed by freeze granulation/freeze-drying resulted in de-agglomerated powders with improved ability to rapidly disperse and, hence, extend the possibility of achieving extreme solids loadings. When approaching the practical limits in solids loading of these pre-milled powders, slips with 49.5 vol% of as-received and 46.6 vol% of calcined powders displayed clear shear thickening behaviour. However, addition of WPC (12 wt% based on water) significantly decreased the degree of shear thickening although the viscosity at lower shear rates increased. The gelling of WPC was distinct and rapid in suspensions with the two pre-milled powders, as-received stabilised at pH 10 and calcined stabilised with Tiron. (orig.)
Machado Neto, Lauro de Vilhena Brandao [Pontificia Universidade Catolica de Minas Gerais (PUC-Minas), Belo Horizonte, MG (Brazil); Cabral, Claudia Valeria Tavora; Oliveira Filho, Delly [Universidade Federal de Vicosa (UFV), MG (Brazil); Diniz, Antonia Sonia Alves Cardoso [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Cortizo, Porfirio Cabaleiro [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil)
2004-07-01
The maximization of the efficiency in the electric energy conversion is essential to the developing of technical and economic viability of photovoltaic solar energy systems. This paper presents the development of an electronic converter with maximum power point tracking for photovoltaic systems applied to rural electrification. The standalone photovoltaic system used is similar to the systems installed by Companhia Energetica de Minas Gerais - CEMIG in the schools of isolated communities, inside the Solar Light Program. Initially were developed test procedures of the equipment used in the system like photovoltaic generators, electronic ballasts, inverters, charge controllers and batteries, covering minimum performance requirements and in compliance with national and international standards, as possible, due to the instrumentation availability. A data acquisition system was assembled to monitoring the photovoltaic system. A simulation of the system was implemented and the aims were to optimize the project and carry out a comparative study with the monitoring results. The converter with maximum power point tracking consists of a direct current converter in the buck configuration and the control algorithm was implemented in a micro controller, being the first results presented here. After finished the prototype, it will be incorporated in the photovoltaic system and will be accomplished a study of the technical and economic viability. The first results of the tests, of the monitoring and of the converter with maximum power point tracking are helping the sustainability of the systems installed by CEMIG, funding the government initiatives in the quality control of equipment and promoting the development of national technology. (author)
Dill, Robert; Klemann, Volker; Martinec, Zdeněk; Tesauro, M.
2015-01-01
The influence of the elastic Earth properties on seasonal or shorter periodic surface deformations due to atmospheric surface pressure and terrestrial water storage variations is usually modeled by applying a local half-space model or an one dimensional spherical Earth model like PREM from which a u
Solberg, Brian; Andersen, Palle; Maciejowski, Jan
2008-01-01
This paper discusses the application of hybrid model predictive control to control switching between different burner modes in a novel compact marine boiler design. A further purpose of the present work is to point out problems with finite horizon model predictive control applied to systems for w...
Ghaedi, M.; Azad, F. Nasiri; Dashtian, K.; Hajati, S.; Goudarzi, A.; Soylak, M.
2016-10-01
Maximum malachite green (MG) adsorption onto ZnO Nanorod-loaded activated carbon (ZnO-NR-AC) was achieved following the optimization of conditions, while the mass transfer was accelerated by ultrasonic. The central composite design (CCD) and genetic algorithm (GA) were used to estimate the effect of individual variables and their mutual interactions on the MG adsorption as response and to optimize the adsorption process. The ZnO-NR-AC surface morphology and its properties were identified via FESEM, XRD and FTIR. The adsorption equilibrium isotherm and kinetic models investigation revealed the well fit of the experimental data to Langmuir isotherm and pseudo-second-order kinetic model, respectively. It was shown that a small amount of ZnO-NR-AC (with adsorption capacity of 20 mg g- 1) is sufficient for the rapid removal of high amount of MG dye in short time (3.99 min).
Refsgaard, A; Jacobsen, T; Jacobsen, B; Ørum, J-E
2007-01-01
The EU Water Framework Directive (WFD) requires an integrated approach to river basin management in order to meet environmental and ecological objectives. This paper presents concepts and full-scale application of an integrated modelling framework. The Ringkoebing Fjord basin is characterized by intensive agricultural production and leakage of nitrate constitute a major pollution problem with respect groundwater aquifers (drinking water), fresh surface water systems (water quality of lakes) and coastal receiving waters (eutrophication). The case study presented illustrates an advanced modelling approach applied in river basin management. Point sources (e.g. sewage treatment plant discharges) and distributed diffuse sources (nitrate leakage) are included to provide a modelling tool capable of simulating pollution transport from source to recipient to analyse the effects of specific, localized basin water management plans. The paper also includes a land rent modelling approach which can be used to choose the most cost-effective measures and the location of these measures. As a forerunner to the use of basin-scale models in WFD basin water management plans this project demonstrates the potential and limitations of comprehensive, integrated modelling tools.
Rodrigues, José Alberto Domingues; Oliveira, Ricardo Polisaitis; Ratusznei, Suzana Maria; Zaiat, Marcelo; Foresti, Eugenio
2011-01-01
A study was performed regarding the effect of the relation between fill time, volume treated per cycle, and influent concentration at different applied organic loadings on the stability and efficiency of an anaerobic sequencing batch reactor containing immobilized biomass on polyurethane foam with recirculation of the liquid phase (AnSBBR) applied to the treatment of wastewater from a personal care industry. Total cycle length of the reactor was 8 h (480 min). Fill times were 10 min in the batch operation, 4 h in the fed-batch operation, and a 10-min batch followed by a 4-h fed batch in the mixed operation. Settling time was not necessary since the biomass was immobilized and decant time was 10 min. Volume of liquid medium in the reactor was 2.5 L, whereas volume treated per cycle ranged from 0.88 to 2.5 L in accordance with fill time. Influent concentration varied from 300 to 1,425 mg COD/L, resulting in an applied volumetric organic load of 0.9 and 1.5 g COD/L.d. Recirculation flow rate was 20 L/h, and the reactor was maintained at 30 °C. Values of organic matter removal efficiency of filtered effluent samples were below 71% in the batch operations and above 74% in the operations of fed batch followed by batch. Feeding wastewater during part of the operational cycle was beneficial to the system, as it resulted in indirect control over the conversion of substrate into intermediates that would negatively interfere with the biochemical reactions regarding the degradation of organic matter. As a result, the average substrate consumption increased, leading to higher organic removal efficiencies in the fed-batch operations.
Maximum information photoelectron metrology
Hockett, P; Wollenhaupt, M; Baumert, T
2015-01-01
Photoelectron interferograms, manifested in photoelectron angular distributions (PADs), are a high-information, coherent observable. In order to obtain the maximum information from angle-resolved photoionization experiments it is desirable to record the full, 3D, photoelectron momentum distribution. Here we apply tomographic reconstruction techniques to obtain such 3D distributions from multiphoton ionization of potassium atoms, and fully analyse the energy and angular content of the 3D data. The PADs obtained as a function of energy indicate good agreement with previous 2D data and detailed analysis [Hockett et. al., Phys. Rev. Lett. 112, 223001 (2014)] over the main spectral features, but also indicate unexpected symmetry-breaking in certain regions of momentum space, thus revealing additional continuum interferences which cannot otherwise be observed. These observations reflect the presence of additional ionization pathways and, most generally, illustrate the power of maximum information measurements of th...
Pigatto, Andre V; Moura, Karina O A; Favieiro, Gabriela W; Balbinot, Alexandre; Pigatto, Andre V; Moura, Karina O A; Favieiro, Gabriela W; Balbinot, Alexandre; Moura, Karina O A; Favieiro, Gabriela W; Balbinot, Alexandre; Pigatto, Andre V
2016-08-01
This report describes the development of a force platform based on instrumented load cells with built-in conditioning circuit and strain gages to measure and acquire the components of the force that is applied to the bike crank arm during pedaling in real conditions, and save them on a SD Card. To accomplish that, a complete new crank arm 3D solid model was developed in the SolidWorks, with dimensions equivalent to a commercial crank set and compatible with a conventional road bike, but with a compartment to support all the electronics necessary to measure 3 components of the force applied to the pedal during pedaling. After that, a 6082 T6 Aluminum Crankset based on the solid model was made and instrumented with three Wheatstone bridges each. The signals were conditioned on a printed circuit board, made on SMD technology, and acquired using a microcontroller with a DAC. Static deformation analysis showed a linearity error below 0.6% for all six channels. Dynamic analysis showed a natural frequency above 136Hz. A one-factor experiment design was performed with 5 amateur cyclists. ANOVA showed that the cyclist weight causes significant variation on the force applied to the bicycle pedal and its bilateral symmetry.
Klos, Anna; Gruszczynska, Marta; Bos, Machiel Simon; Boy, Jean-Paul; Bogusz, Janusz
2017-02-01
A reliable subtraction of seasonal signals from the Global Positioning System (GPS) position time series is beneficial for the accuracy of derived velocities. In this research, we propose a two-stage solution of the problem of a proper determination of seasonal changes. We employ environmental loading models (atmospheric, hydrological and ocean non-tidal) with a dominant annual signal of amplitudes in their superposition of up to 12 mm and study the seasonal signal (annual and semi-annual) estimates that change over time using improved singular spectrum analysis (ISSA). Then, this deterministic model is subtracted from GPS position time series. We studied data from 376 permanent International GNSS Service (IGS) stations, derived as the official contribution to International Terrestrial Reference Frame (ITRF2014) to measure the influence of applying environmental loading models on the estimated vertical velocity. Having removed the environmental loadings directly from the position time series, we noticed the evident change in the power spectrum for frequencies between 4 and 80 cpy. Therefore, we modelled the seasonal signal in environmental models using the ISSA approach and subtracted it from GPS vertical time series to leave the noise character of the time series intact. We estimated the velocity dilution of precision (DP) as a ratio between classical Weighted Least Squares and ISSA approach. For a total number of 298 out of the 376 stations analysed, the DP was lower than 1. This indicates that when the ISSA-derived curve was removed from the GPS data, the error of velocity becomes lower than it was before.
Romel Dias Vanderlei
2007-01-01
Full Text Available Este trabalho analisa o comportamento de pilares feitos com concreto de alto desempenho, com resistência média à compressão de 80 MPa, submetidos à compressão excêntrica. Os pilares apresentam seção transversal retangular de 15 x 30 cm e comprimento livre de 174 cm. São analisados seis pilares, em que as variáveis são as taxas de armaduras transversais e longitudinais. Foram montados dispositivos de vinculações e sistema de transferências de forças, procurando aproximar as situações de ensaios às do modelo teórico pretendido. Os pilares com menores taxas de armadura transversal tiveram ruptura frágil com flambagem das barras das armaduras longitudinais. Os pilares com maiores taxas de armadura transversal apresentaram ruptura com ductilidade e esmagamento do concreto do lado mais comprimido. Utilizaram-se modelos teóricos para obter os valores estimados das forças últimas e momentos fletores últimos, e estes foram comparados com os encontrados experimentalmente.This paper analyzes the behavior of columns under eccentric loading, with concrete compressive strength of around 80 MPa. The columns have cross section area of 15 x 30 cm at the test region, and an effective length of 174 cm. Six columns were tested. The main variables are the stirrup volumetric ratio and the longitudinal steel ratio. Articulation devices and load application devices were mounted in order to approach the proposed theoretical model as much as possible. The columns with smaller stirrup volumetric ratio showed a brittle mode of failure accompanied by the buckling of the longitudinal reinforcement. Differently, the columns with larger stirrup volumetric ratio presented ductile failure accompanied by concrete crushing on the most compressed side of the column. Theoretical models were used to obtain values of the maximum axial loads andultimate flexural moment. The results were compared with the experimental ones obtained in the tests.
Khaled M. Saadeldin Eldalil
2009-01-01
Full Text Available The load acting on the actively controlled cylindrical shell under a transient pressure pulse propelling a moving mass (gun case has been experimentally studied. The concept of using piezoelectric stack and stiffener combination is utilized for damping the tube wall radial and circumferential deforming vibrations, in the correct meeting location timing of the moving mass. The experiment was carried out by using the same stiffened shell tube of the experimental 14 mm gun tube facility which is used in part 1. Using single and double stacks is tried at two pressure levels of low-speed modes, which have response frequencies adapted with the used piezoelectric stacks characteristics. The maximum active damping ratio is occurred at high-pressure level. The radial circumferential strains are measured by using high-frequency strain gage system in phase with laser beam detection system similar to which used in part 1. Time resolved strain measurements of the wall response were obtained, and both precursor and transverse hoop strains have been resolved. A complete comparison had been made between the effect of active controlled and stepped structure cases, which indicate a significant attenuation ratio especially at higher operating pressures.
G.G. Zhemerov
2015-12-01
Full Text Available Purpose. The contradictions in the use of the term «reactive power» require justification by clarifying its physical meaning. The aim of the paper is to reveal the physical meaning of the term «reactive power» applied to three-phase three-wire and four-wire energy supply systems. Methodology. We have applied the modern theory of instantaneous active and reactive power, the graphical filling complex branched energy supply system of simplified design scheme, the theory of electrical circuits, computer Matlab-simulation. Results. We have provided answers to six basic questions that reveal the physical meaning and definition of the concept of «reactive power». We have justified the assumptions suggesting a universal calculation formula to determine the relative total power loss in the three-phase energy supply system as the sum of four components caused by: a minimal losses, reactive power, active power pulsations and instantaneous current flow in the neutral wire. Originality. We have developed the definition that reveals the physical meaning of the term «reactive power» for three-phase energy supply systems corresponding to modern theories of instantaneous active and reactive power. Practical value. We have proposed energy efficiency method ideas of energy supply systems with non-linear load based on the additional components of the power losses calculation. The further development of the method will allow to amend the design, selection and operation of the power active filters practices.
Regularized maximum correntropy machine
Wang, Jim Jing-Yan
2015-02-12
In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.
Gilberto Silvério da Silva
2007-06-01
Full Text Available Neste estudo foram avaliadas a capacidade de suporte e o estado de degradação do Rio Atibaia, considerando a ameaça para a vida aquática pela presença da Amônia, a qual representa um dos principais riscos às comunidades aquáticas no Rio Atibaia. Com este objetivo foi aplicado o método da Carga Máxima Total Diária (CMTD, da Agência de Proteção Ambiental dos Estados Unidos (EPA. Os resultados revelaram que as cargas de Amônia aumentavam progressivamente ao longo do Rio Atibaia, principalmente devido às fontes pontuais. As cargas de Amônia diárias assumiram valores de 30 a 5000 kg NH3. A capacidade de suporte das águas Rio Atibaia, para proteger a vida aquática contra os efeitos tóxicos da Amônia, tem sido violadas em trechos próximos à sua foz. A degradação dessas águas foi mais intensa na estação seca. Este trabalho mostrou que o esgoto doméstico não-tratado de uma população aproximada de 250 mil habitantes da cidade de Campinas, via Ribeirão Anhumas, é a principal fonte de Amônia na bacia do Rio Atibaia, apesar do grande número de indústrias ali presentes.This study evaluated the tolerance capacity and the impairment state of the Atibaia River, considering the threat to aquatic life by the presence of Ammonia, which represents one of the main risks to the aquatic communities in the Atibaia River. With this aim, the method Total Maximum Daily Load (TMDL, from the United States Environmental Protection Agency (EPA, was applied. The results revealed that the Ammonia loads increased progressively through the Atibaia River, especially due to the point sources. The daily Ammonia loads assumed values that ranged from 30 to 5000 kg NH3. The tolerance capacity of the waters of the Atibaia River, to protect aquatic life against the toxic effects of the Ammonia, has been violated in reaches near its mouth. The impairment of these waters was more intense during the dry season. This study showed that the domestic sewer
B. E. L. Baêta
Full Text Available Abstract This paper evaluated the treatment of textile wastewater in submerged anaerobic membrane bioreactors (SAMBR operated on a bench scale. Particularly, the influence of operational conditions, such as the applied organic rate (OLR and the dilution factor (for toxicity attenuation of the textile wastewater, was evaluated on color and organic matter removal. In addition, the effect of powdered activated carbon (PAC on SAMBR-1 and the addition of yeast extract (source of the redox mediator riboflavin were also investigated. The results showed that reducing the textile wastewater dilution factor from 10× (phase 1 to 4× (phase 2 and 0× (no dilution decreased the COD and color removal efficiencies in both SAMBRs, probably due to an increase in the toxic load. Nevertheless, PAC adsorbed toxic compounds found in the textile wastewater and helped biomass acclimatization, which led to higher COD and color removal efficiencies in SAMBR-1. The presence of yeast extract enhanced color removal efficiencies 3-fold in both SAMBRs when they were fed with undiluted textile wastewater.
Abolishing the maximum tension principle
Dabrowski, Mariusz P
2015-01-01
We find the series of example theories for which the relativistic limit of maximum tension $F_{max} = c^2/4G$ represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.
Abolishing the maximum tension principle
Mariusz P. Da̧browski
2015-09-01
Full Text Available We find the series of example theories for which the relativistic limit of maximum tension Fmax=c4/4G represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.
Maximum Autocorrelation Factorial Kriging
Nielsen, Allan Aasbjerg; Conradsen, Knut; Pedersen, John L.
2000-01-01
This paper describes maximum autocorrelation factor (MAF) analysis, maximum autocorrelation factorial kriging, and its application to irregularly sampled stream sediment geochemical data from South Greenland. Kriged MAF images are compared with kriged images of varimax rotated factors from...
Distribution load estimation - DLE
Seppaelae, A. [VTT Energy, Espoo (Finland)
1996-12-31
The load research project has produced statistical information in the form of load models to convert the figures of annual energy consumption to hourly load values. The reliability of load models is limited to a certain network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to make improvements in the load models. Distribution load estimation (DLE) is the method developed here to improve load estimates from the load models. The method is also quite cheap to apply as it utilises information that is already available in SCADA systems
2014-09-01
photovoltaic ROM read only memory SLR series-loaded resonant VHDL VHSIC hardware description language VHSIC very high speed integrated circuit ZCS zero...high level simulation compiler that produces VHSIC hardware description language ( VHDL ) code for the model built in Simulink. With the VHDL code, the
Distribution load estimation (DLE)
Seppaelae, A.; Lehtonen, M. [VTT Energy, Espoo (Finland)
1998-08-01
The load research has produced customer class load models to convert the customers` annual energy consumption to hourly load values. The reliability of load models applied from a nation-wide sample is limited in any specific network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to find improvements to the load models or, in general, improvements to the load estimates. In Distribution Load Estimation (DLE) the measurements from the network are utilized to improve the customer class load models. The results of DLE will be new load models that better correspond to the loading of the distribution network but are still close to the original load models obtained by load research. The principal data flow of DLE is presented
LOAD CARRYING CAPABILITY OF LIQUID FILLED CYLINDRICAL SHELL STRUCTURES UNDER AXIAL COMPRESSION
QASIM H. SHAH
2011-08-01
Full Text Available Empty and water filled cylindrical Tin (Sn coated steel cans were loaded under axial compression at varying loading rates to study their resistance to withstand accidental loads. Compared to empty cans the water filled cans exhibit greater resistance to axially applied compression loads before a complete collapse. The time and load or stroke and load plots showed three significant load peaks related to three stages during loading until the cylinder collapse. First peak corresponds to the initial structural buckling of can. Second peak occurs when cylindrical can walls gradually come into full contact with water. The third peak shows the maximum load carrying capability of the structure where pressurized water deforms the can walls into curved shape until can walls fail under peak pressure. The collapse process of water filled cylindrical shell was further studied using Smooth Particle Hydrodynamics (SPH technique in LSDYNA. Load peaks observed in the experimental work were successfully simulated which substantiated the experimental work.
Blackwell, Mark W.; Tutty, Owen R.; Rogers, Eric; Sandberg, Richard D.
2016-01-01
The inclusion of smart devices in wind turbine rotor blades could, in conjunction with collective and individual pitch control, improve the aerodynamic performance of the rotors. This is currently an active area of research with the primary objective of reducing the fatigue loads but mitigating the effects of extreme loads is also of interest. The aerodynamic loads on a wind turbine blade contain periodic and non-periodic components and one approach is to consider the application of iterative learning control algorithms. In this paper, the control design is based on a simple, in relative terms, computational fluid dynamics model that uses non-linear wake effects to represent flow past an airfoil. A representation for the actuator dynamics is included to undertake a detailed investigation into the level of control possible and on how performance can be effectively measured.
Maximum Entropy in Drug Discovery
Chih-Yuan Tseng
2014-07-01
Full Text Available Drug discovery applies multidisciplinary approaches either experimentally, computationally or both ways to identify lead compounds to treat various diseases. While conventional approaches have yielded many US Food and Drug Administration (FDA-approved drugs, researchers continue investigating and designing better approaches to increase the success rate in the discovery process. In this article, we provide an overview of the current strategies and point out where and how the method of maximum entropy has been introduced in this area. The maximum entropy principle has its root in thermodynamics, yet since Jaynes’ pioneering work in the 1950s, the maximum entropy principle has not only been used as a physics law, but also as a reasoning tool that allows us to process information in hand with the least bias. Its applicability in various disciplines has been abundantly demonstrated. We give several examples of applications of maximum entropy in different stages of drug discovery. Finally, we discuss a promising new direction in drug discovery that is likely to hinge on the ways of utilizing maximum entropy.
Serpil GOK TANGOLAR
2015-12-01
Full Text Available This study evaluated the effects of various bud load and water amounts (WA on the berry composition of the ‘Narince’ white wine grape variety. Two water amounts (WA-I and WA-II administered during growth stages or a non-irrigated (rain-fed control treatment were paired with two different bud loads (K (normal and 2K (two-fold buds to assess their effects on sugar, organic acid and phenolic compound contents, as well as antioxidant capacity of the berries for a white wine grape variety ‘Narince’. Despite a slight decrease observed only in sugars in the second year, increases in all phenolic compounds examined (especially in catechin and epicatechin were detected in the WA-I application. The total phenolic compound values obtained for 2K in the same application was also high. The antioxidant capacity values were not significantly affected by the irrigation or bud load applications. Therefore, a 2K bud load with WA-I treatments in which 50% and 75% of the cumulative evaporation from the Class A pan during berry set to veraison and veraison to ripening, respectively, are recommended for irrigation in high plateau viticulture. By maintaining or increasing the fruit composition of ‘Narince’ grapes, these treatments can optimize grape yield and the earnings of growers. In all applications, glucose (among the sugars, tartaric acid (among the organic acids, and catechin and epicatechin (among the phenolic compounds were higher than their counterparts.
Barboza, Luciano Vitoria [Sul-riograndense Federal Institute for Education, Science and Technology (IFSul), Pelotas, RS (Brazil)], E-mail: luciano@pelotas.ifsul.edu.br
2009-07-01
This paper presents an overview about the maximum load ability problem and aims to study the main factors that limit this load ability. Specifically this study focuses its attention on determining which electric system buses influence directly on the power demand supply. The proposed approach uses the conventional maximum load ability method modelled by an optimization problem. The solution of this model is performed using the Interior Point methodology. As consequence of this solution method, the Lagrange multipliers are used as parameters that identify the probable 'bottlenecks' in the electric power system. The study also shows the relationship between the Lagrange multipliers and the cost function in the Interior Point optimization interpreted like sensitivity parameters. In order to illustrate the proposed methodology, the approach was applied to an IEEE test system and to assess its performance, a real equivalent electric system from the South- Southeast region of Brazil was simulated. (author)
Maximum Autocorrelation Factorial Kriging
Nielsen, Allan Aasbjerg; Conradsen, Knut; Pedersen, John L.; Steenfelt, Agnete
2000-01-01
This paper describes maximum autocorrelation factor (MAF) analysis, maximum autocorrelation factorial kriging, and its application to irregularly sampled stream sediment geochemical data from South Greenland. Kriged MAF images are compared with kriged images of varimax rotated factors from an ordinary non-spatial factor analysis, and they are interpreted in a geological context. It is demonstrated that MAF analysis contrary to ordinary non-spatial factor analysis gives an objective discrimina...
Omar Herrera - Sánchez
2010-05-01
renewable source of energy totally, either because the country isvery small, or because it coincides the area of more potential fully with that of high risk. To counteractthis situation, a model of analysis of maxims loads has been elaborated taken place the extremewinds in wind turbines of great behavior. This model has the advantage of determining, in a chosenplace, for the installation of a wind farm, the micro-areas with higher risk of wind loads above theacceptable for the standard classes of wind turbines.Key words: Wind turbines, wind loads, modeling of wind farm.
Assessment of New Load Schedules for the Machine Calibration of a Force Balance
Ulbrich, N.; Gisler, R.; Kew, R.
2015-01-01
New load schedules for the machine calibration of a six-component force balance are currently being developed and evaluated at the NASA Ames Balance Calibration Laboratory. One of the proposed load schedules is discussed in the paper. It has a total of 2082 points that are distributed across 16 load series. Several criteria were applied to define the load schedule. It was decided, for example, to specify the calibration load set in force balance format as this approach greatly simplifies the definition of the lower and upper bounds of the load schedule. In addition, all loads are assumed to be applied in a calibration machine by using the one-factor-at-a-time approach. At first, all single-component loads are applied in six load series. Then, three two-component load series are applied. They consist of the load pairs (N1, N2), (S1, S2), and (RM, AF). Afterwards, four three-component load series are applied. They consist of the combinations (N1, N2, AF), (S1, S2, AF), (N1, N2, RM), and (S1, S2, RM). In the next step, one four-component load series is applied. It is the load combination (N1, N2, S1, S2). Finally, two five-component load series are applied. They are the load combination (N1, N2, S1, S2, AF) and (N1, N2, S1, S2, RM). The maximum difference between loads of two subsequent data points of the load schedule is limited to 33 % of capacity. This constraint helps avoid unwanted load "jumps" in the load schedule that can have a negative impact on the performance of a calibration machine. Only loadings of the single- and two-component load series are loaded to 100 % of capacity. This approach was selected because it keeps the total number of calibration points to a reasonable limit while still allowing for the application of some of the more complex load combinations. Data from two of NASA's force balances is used to illustrate important characteristics of the proposed 2082-point calibration load schedule.
Artificial Intelligence for Load Management Based On Load Shifting in the Textile Industry
Chaimongkon Chokpanyasuwan
2015-02-01
Full Text Available The target of any load management is to maintain a constant level of load. The important benefits of load management are reduction in maximum demand, reduction in power loss, better equipment utilization and saving through reduced maximum demand charges. Load shifting, one of the simplest methods of load management, is to reduce customer demand during the peak period by shifting the use of appliances and equipment to partial peak and on-peak periods. This paper proposes an application of artificial intelligent (AI optimization methods i.e. genetic algorithm (GA, particle swarm optimization (PSO and bee algorithm (BA to develop the load shifting and the same has been tried with the actual load data collected from the textile industry plant. The objective is to minimize the total electricity tariff cost. The methodology proposed can be used for determining the optimal response for textile industry under time varying tariffs such as flat rate and time of use (TOU.To show its efficiency, the AI methods are applied to solve the case studies in case of single process multi-jobs (SPMJ. The results show that the proposed methods are able to achieve the best solution efficiently and easy to implement.
Prosthetic abutment influences bone biomechanical behavior of immediately loaded implants.
Camargos, Germana de Villa; Sotto-Maior, Bruno Salles; Silva, Wander José da; Lazari, Priscilla Cardoso; Del Bel Cury, Altair Antoninha
2016-05-31
This study aimed to evaluate the influence of the type of prosthetic abutment associated to different implant connection on bone biomechanical behavior of immediately and delayed loaded implants. Computed tomography-based finite element models comprising a mandible with a single molar implant were created with different types of prosthetic abutment (UCLA or conical), implant connection (external hexagon, EH or internal hexagon, IH), and occlusal loading (axial or oblique), for both immediately and delayed loaded implants. Analysis of variance at 95%CI was used to evaluate the peak maximum principal stress and strain in bone after applying a 100 N occlusal load. The results showed that the type of prosthetic abutment influences bone stress/strain in only immediately loaded implants. Attachment of conical abutments to IH implants exhibited the best biomechanical behavior, with optimal distribution and dissipation of the load in peri-implant bone.
Prosthetic abutment influences bone biomechanical behavior of immediately loaded implants
Germana de Villa CAMARGOS
2016-01-01
Full Text Available Abstract This study aimed to evaluate the influence of the type of prosthetic abutment associated to different implant connection on bone biomechanical behavior of immediately and delayed loaded implants. Computed tomography-based finite element models comprising a mandible with a single molar implant were created with different types of prosthetic abutment (UCLA or conical, implant connection (external hexagon, EH or internal hexagon, IH, and occlusal loading (axial or oblique, for both immediately and delayed loaded implants. Analysis of variance at 95%CI was used to evaluate the peak maximum principal stress and strain in bone after applying a 100 N occlusal load. The results showed that the type of prosthetic abutment influences bone stress/strain in only immediately loaded implants. Attachment of conical abutments to IH implants exhibited the best biomechanical behavior, with optimal distribution and dissipation of the load in peri-implant bone.
Maximum gain of Yagi-Uda arrays
Bojsen, J.H.; Schjær-Jacobsen, Hans; Nilsson, E.
1971-01-01
Numerical optimisation techniques have been used to find the maximum gain of some specific parasitic arrays. The gain of an array of infinitely thin, equispaced dipoles loaded with arbitrary reactances has been optimised. The results show that standard travelling-wave design methods are not optimum....... Yagi–Uda arrays with equal and unequal spacing have also been optimised with experimental verification....
The maximum rotation of a galactic disc
Bottema, R
1997-01-01
The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB) galaxies because such systems show, in general, a continuously
Maximum-likelihood method in quantum estimation
Paris, M G A; Sacchi, M F
2001-01-01
The maximum-likelihood method for quantum estimation is reviewed and applied to the reconstruction of density matrix of spin and radiation as well as to the determination of several parameters of interest in quantum optics.
Fenton, Tanis R; Tough, Suzanne C; Lyon, Andrew W; Eliasziw, Misha; Hanley, David A
2011-04-30
Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria. Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined. Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy). The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism functioning at physiological pH. Finally, randomized studies
Lyon Andrew W
2011-04-01
Full Text Available Abstract Background Modern diets have been suggested to increase systemic acid load and net acid excretion. In response, alkaline diets and products are marketed to avoid or counteract this acid, help the body regulate its pH to prevent and cure disease. The objective of this systematic review was to evaluate causal relationships between dietary acid load and osteoporosis using Hill's criteria. Methods Systematic review and meta-analysis. We systematically searched published literature for randomized intervention trials, prospective cohort studies, and meta-analyses of the acid-ash or acid-base diet hypothesis with bone-related outcomes, in which the diet acid load was altered, or an alkaline diet or alkaline salts were provided, to healthy human adults. Cellular mechanism studies were also systematically examined. Results Fifty-five of 238 studies met the inclusion criteria: 22 randomized interventions, 2 meta-analyses, and 11 prospective observational studies of bone health outcomes including: urine calcium excretion, calcium balance or retention, changes of bone mineral density, or fractures, among healthy adults in which acid and/or alkaline intakes were manipulated or observed through foods or supplements; and 19 in vitro cell studies which examined the hypothesized mechanism. Urine calcium excretion rates were consistent with osteoporosis development; however calcium balance studies did not demonstrate loss of whole body calcium with higher net acid excretion. Several weaknesses regarding the acid-ash hypothesis were uncovered: No intervention studies provided direct evidence of osteoporosis progression (fragility fractures, or bone strength as measured using biopsy. The supporting prospective cohort studies were not controlled regarding important osteoporosis risk factors including: weight loss during follow-up, family history of osteoporosis, baseline bone mineral density, and estrogen status. No study revealed a biologic mechanism
Ándonios D. Tsolakis
2011-01-01
Full Text Available Problem statement: Main purpose of this study was to investigation toothed gear loading problems using the Finite Element Method. Approach: We used Niemann's equations to compare maximum bending stress which was developed at critical gear-tooth flank point during gear meshing, applied for three distinct spur-gear sizes, each having different teeth number, module and power rating. Results: The results emerging after the application of Niemann's equations were compared to the results derived by application of the Finite Element Method (FEM for the same gear-loading input data. Results are quite satisfactory, since von Mises' equivalent stresses calculated with FEM are of the same order with the results of classical analytical method. Conclusion: Judging from the emerging results, deviation of the two methods, analytical (Niemann's equations and computational (FEM, referring to maximum bending stress is fairly slight, independently of the applied geometrical and loading data of each gear.
倪晓
2012-01-01
概述了美国环保局提出的最大日负荷量（TMDL）计划的概念、目标及具体实施步骤，其实践表明：TMDL计划对改善水质是行之有效的。讨论分析了与美国TMDL计划实施过程相比，我国污染物总量控制实施TMDL计划可能存在的问题。最后提出了以流域水生态健康为出发点，结合我国流域实际情况，重视非点源污染，开发简单、经济、实用的污染负荷估算模型，制订了适宜我国流域水污染物总量控制的TMDL计划，并结合其他污染控制措施，以最终实现流域水生态健康。%This article summarizes the concept, objective and specific implementation steps ot the IMDL program wnlcn is issued by U. S. EPA. And through successful practices, the TMDL program has been proved effective for improving water quality. Compared with the application of TMDL program in U. S. , this article discusses the problems that may exist in the implementation progress of the TMDL program in China. Finally, starting from the water ecological health of river basin and combining the actual situation of basins in China, the article proposes to focus on non - point source pollution, develop a simple, economical and practical model for evaluation of pollution loads, makes a TMDL plan suitable for China, and combines with other control measures, so as to achieve the water ecological health of river basin.
The maximum entropy technique. System's statistical description
Belashev, B Z
2002-01-01
The maximum entropy technique (MENT) is applied for searching the distribution functions of physical values. MENT takes into consideration the demand of maximum entropy, the characteristics of the system and the connection conditions, naturally. It is allowed to apply MENT for statistical description of closed and open systems. The examples in which MENT had been used for the description of the equilibrium and nonequilibrium states and the states far from the thermodynamical equilibrium are considered
Maximum life spiral bevel reduction design
Savage, M.; Prasanna, M. G.; Coe, H. H.
1992-07-01
Optimization is applied to the design of a spiral bevel gear reduction for maximum life at a given size. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial values. Gear tooth bending strength and minimum contact ratio under load are included in the active constraints. The optimal design of the spiral bevel gear reduction includes the selection of bearing and shaft proportions in addition to gear mesh parameters. System life is maximized subject to a fixed back-cone distance of the spiral bevel gear set for a specified speed ratio, shaft angle, input torque, and power. Significant parameters in the design are: the spiral angle, the pressure angle, the numbers of teeth on the pinion and gear, and the location and size of the four support bearings. Interpolated polynomials expand the discrete bearing properties and proportions into continuous variables for gradient optimization. After finding the continuous optimum, a designer can analyze near optimal designs for comparison and selection. Design examples show the influence of the bearing lives on the gear parameters in the optimal configurations. For a fixed back-cone distance, optimal designs with larger shaft angles have larger service lives.
Santra, Kalyan; Zhan, Jinchun; Song, Xueyu; Smith, Emily A; Vaswani, Namrata; Petrich, Jacob W
2016-03-10
The need for measuring fluorescence lifetimes of species in subdiffraction-limited volumes in, for example, stimulated emission depletion (STED) microscopy, entails the dual challenge of probing a small number of fluorophores and fitting the concomitant sparse data set to the appropriate excited-state decay function. This need has stimulated a further investigation into the relative merits of two fitting techniques commonly referred to as "residual minimization" (RM) and "maximum likelihood" (ML). Fluorescence decays of the well-characterized standard, rose bengal in methanol at room temperature (530 ± 10 ps), were acquired in a set of five experiments in which the total number of "photon counts" was approximately 20, 200, 1000, 3000, and 6000 and there were about 2-200 counts at the maxima of the respective decays. Each set of experiments was repeated 50 times to generate the appropriate statistics. Each of the 250 data sets was analyzed by ML and two different RM methods (differing in the weighting of residuals) using in-house routines and compared with a frequently used commercial RM routine. Convolution with a real instrument response function was always included in the fitting. While RM using Pearson's weighting of residuals can recover the correct mean result with a total number of counts of 1000 or more, ML distinguishes itself by yielding, in all cases, the same mean lifetime within 2% of the accepted value. For 200 total counts and greater, ML always provides a standard deviation of <10% of the mean lifetime, and even at 20 total counts there is only 20% error in the mean lifetime. The robustness of ML advocates its use for sparse data sets such as those acquired in some subdiffraction-limited microscopies, such as STED, and, more importantly, provides greater motivation for exploiting the time-resolved capacities of this technique to acquire and analyze fluorescence lifetime data.
Alcir José Modolo
2010-06-01
Full Text Available Dentre os fatores primordiais para a germinação estão a umidade, a temperatura e a aeração do solo. É importante citar que esses fatores são diretamente influenciados pelo estado de compactação do solo ao redor da semente. Objetivou-se, neste trabalho, estudar os efeitos da combinação entre profundidades de semeadura e cargas aplicadas pela roda compactadora da semeadora-adubadora sobre o desenvolvimento da cultura do feijão, em sistema plantio direto. Foi utilizado o esquema fatorial no delineamento em blocos ao acaso, composto por doze tratamentos (três profundidades de semeadura e quatro níveis de cargas aplicadas pela roda compactadora e quatro repetições. Os resultados mostraram que a profundidade de semeadura influenciou, significativamente, o índice de velocidade de emergência, os estandes inicial e final de plantas e o rendimento da cultura. As diferentes cargas aplicadas pela roda compactadora não influenciaram significativamente as variáveis avaliadas.Among the primordial factors for the germination are humidity, temperature, and aeration of the soil. It is important to mention that these factors are directly influenced by the soil compaction state around the seed. The present paper had the aim of studying the effects of the combination between depths of sowing and loads applied by press wheel of the seeder upon the development of bean culture, in a no-tillage system. Factor schedule was applied to the delineation in random blocks composed by twelve treatments (three depths of sowing and four levels of loads applied by the press wheel and four replications. The results showed that depth of sowing significantly influenced the index of emergency speed, the initial and final stands of plants and yield of culture. The different loads applied for the press wheel did not significantly influence the evaluated variables.
Maximum likely scale estimation
Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo
2005-01-01
A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and/or ...
Analysis of Photovoltaic Maximum Power Point Trackers
Veerachary, Mummadi
The photovoltaic generator exhibits a non-linear i-v characteristic and its maximum power point (MPP) varies with solar insolation. An intermediate switch-mode dc-dc converter is required to extract maximum power from the photovoltaic array. In this paper buck, boost and buck-boost topologies are considered and a detailed mathematical analysis, both for continuous and discontinuous inductor current operation, is given for MPP operation. The conditions on the connected load values and duty ratio are derived for achieving the satisfactory maximum power point operation. Further, it is shown that certain load values, falling out of the optimal range, will drive the operating point away from the true maximum power point. Detailed comparison of various topologies for MPPT is given. Selection of the converter topology for a given loading is discussed. Detailed discussion on circuit-oriented model development is given and then MPPT effectiveness of various converter systems is verified through simulations. Proposed theory and analysis is validated through experimental investigations.
Argaud, J.P.
1995-12-01
I Physical description of P.W.R nuclear core can be handled by multigroup neutronic diffusion model. We are interested in two problems, using the same approach for the optimization aspect. To deal with some differences between calculations and measurements, the question of their reduction is then introduced. A reflector parameters identification from core measurements is then purposed, the reflector being at the present time the less known part of core diffusion model. This approach conducts to study the reflector model, in particular by an analysis of its transport origin. It leads finally to a new model of reflector described by boundary operators using an integral formulation on the core/reflector interface. That is on this new model that a parameter identification formulation of calculations-measurements differences reduction is given, using an adjoint state formulation to minimize errors by a gradient method. Furthermore, nuclear fuel reload of P.W.R core needs an optimal distribution of fuel assemblies, namely a loading pattern. This combinatorial optimization problem is then expressed as a cost function minimization, the cost function describing the power spatial distribution. Various methods (linear programming, simulated annealing,...), used to solve this problem, are detailed, given in particular a practical search example. A new approach is then proposed, using the gradient of the cost function to direct the search in the patterns discrete space. Final results of complete patterns search trials are presented, and compared to those obtained by other methods. In particular the results are obtained very quickly. (author). 81 refs., 55 figs., 5 appends.
Cortical and trabecular load sharing in the human femoral neck.
Nawathe, Shashank; Nguyen, Bich Phuong; Barzanian, Nasim; Akhlaghpour, Hosna; Bouxsein, Mary L; Keaveny, Tony M
2015-03-18
The relative role of the cortical vs trabecular bone in the load-carrying capacity of the proximal femur-a fundamental issue in both basic-science and clinical biomechanics-remains unclear. To gain insight into this issue, we performed micro-CT-based, linear elastic finite element analysis (61.5-micron-sized elements; ~280 million elements per model) on 18 proximal femurs (5M, 13F, ages 61-93 years) to quantify the fraction of frontal-plane bending moment shared by the cortical vs trabecular bone in the femoral neck, as well as the associated spatial distributions of stress. Analyses were performed separately for a sideways fall and stance loading. For both loading modes and across all 18 bones, we found consistent patterns of load-sharing in the neck: most proximally, the trabecular bone took most of the load; moving distally, the cortical bone took increasingly more of the load; and more distally, there was a region of uniform load-sharing, the cortical bone taking the majority of the load. This distal region of uniform load-sharing extended more for fall than stance loading (77 ± 8% vs 51 ± 6% of the neck length for fall vs. stance; mean ± SD) but the fraction of total load taken by the cortical bone in that region was greater for stance loading (88 ± 5% vs. 64 ± 9% for stance vs. fall). Locally, maximum stress levels occurred in the cortical bone distally, but in the trabecular bone proximally. Although the distal cortex showed qualitative stress distributions consistent with the behavior of an Euler-type beam, quantitatively beam theory did not apply. We conclude that consistent and well-delineated regions of uniform load-sharing and load-transfer between the cortical and trabecular bone exist within the femoral neck, the details of which depend on the external loading conditions.
Maximum Likelihood Associative Memories
Gripon, Vincent; Rabbat, Michael
2013-01-01
Associative memories are structures that store data in such a way that it can later be retrieved given only a part of its content -- a sort-of error/erasure-resilience property. They are used in applications ranging from caches and memory management in CPUs to database engines. In this work we study associative memories built on the maximum likelihood principle. We derive minimum residual error rates when the data stored comes from a uniform binary source. Second, we determine the minimum amo...
Maximum likely scale estimation
Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo
2005-01-01
A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and....../or having different derivative orders. Although the principle is applicable to a wide variety of image models, the main focus here is on the Brownian model and its use for scale selection in natural images. Furthermore, in the examples provided, the simplifying assumption is made that the behavior...... of the measurements is completely characterized by all moments up to second order....
Functional Maximum Autocorrelation Factors
Larsen, Rasmus; Nielsen, Allan Aasbjerg
2005-01-01
Purpose. We aim at data where samples of an underlying function are observed in a spatial or temporal layout. Examples of underlying functions are reflectance spectra and biological shapes. We apply functional models based on smoothing splines and generalize the functional PCA in\\verb+~+\\$\\backsl......Purpose. We aim at data where samples of an underlying function are observed in a spatial or temporal layout. Examples of underlying functions are reflectance spectra and biological shapes. We apply functional models based on smoothing splines and generalize the functional PCA in...
daily nigerian nigerian nigerian peak load forec peak load forec ...
User
is generally needed for control and scheduling power system and also as inputs to load flo analysis .... Figure 1 Seasonal indices computing neural network ... Feedback paths are sometimes used. In applying a neural network to electric load ...
Maximum likelihood polynomial regression for robust speech recognition
LU Yong; WU Zhenyang
2011-01-01
The linear hypothesis is the main disadvantage of maximum likelihood linear re- gression （MLLR）. This paper applies the polynomial regression method to model adaptation and establishes a nonlinear model adaptation algorithm using maximum likelihood polyno
F. TopsÃƒÂ¸e
2001-09-01
Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over
Clean Water Act Approved Total Maximum Daily Load (TMDL) Documents
U.S. Environmental Protection Agency — Information from Approved and Established TMDL Documents as well as TMDLs that have been Withdrawn. This includes the pollutants identified in the TMDL Document, the...
Task 0715: Army Chesapeake Bay Total Maximum Daily Load Pilots
2011-05-01
NDCEE/CTC The NDCEE is operated by: Office of the Assistant Sec etary of the Army for Installations, E ergy and Enviro ment Technology Transition...Center for Energy and Environment 4) Guidebook and Training Development/Delivery (Future) Guidebook – Capture lessons learned from implementation of
Lihui Guo
2015-01-01
Full Text Available With the increasing penetration of wind power, the randomness and volatility of wind power output would have a greater impact on safety and steady operation of power system. In allusion to the uncertainty of wind speed and load demand, this paper applied box set robust optimization theory in determining the maximum allowable installed capacity of wind farm, while constraints of node voltage and line capacity are considered. Optimized duality theory is used to simplify the model and convert uncertainty quantities in constraints into certainty quantities. Under the condition of multi wind farms, a bilevel optimization model to calculate penetration capacity is proposed. The result of IEEE 30-bus system shows that the robust optimization model proposed in the paper is correct and effective and indicates that the fluctuation range of wind speed and load and the importance degree of grid connection point of wind farm and load point have impact on the allowable capacity of wind farm.
Equalized near maximum likelihood detector
2012-01-01
This paper presents new detector that is used to mitigate intersymbol interference introduced by bandlimited channels. This detector is named equalized near maximum likelihood detector which combines nonlinear equalizer and near maximum likelihood detector. Simulation results show that the performance of equalized near maximum likelihood detector is better than the performance of nonlinear equalizer but worse than near maximum likelihood detector.
Cheeseman, Peter; Stutz, John
2005-01-01
A long standing mystery in using Maximum Entropy (MaxEnt) is how to deal with constraints whose values are uncertain. This situation arises when constraint values are estimated from data, because of finite sample sizes. One approach to this problem, advocated by E.T. Jaynes [1], is to ignore this uncertainty, and treat the empirically observed values as exact. We refer to this as the classic MaxEnt approach. Classic MaxEnt gives point probabilities (subject to the given constraints), rather than probability densities. We develop an alternative approach that assumes that the uncertain constraint values are represented by a probability density {e.g: a Gaussian), and this uncertainty yields a MaxEnt posterior probability density. That is, the classic MaxEnt point probabilities are regarded as a multidimensional function of the given constraint values, and uncertainty on these values is transmitted through the MaxEnt function to give uncertainty over the MaXEnt probabilities. We illustrate this approach by explicitly calculating the generalized MaxEnt density for a simple but common case, then show how this can be extended numerically to the general case. This paper expands the generalized MaxEnt concept introduced in a previous paper [3].
Efficiency at maximum power of a discrete feedback ratchet
Jarillo, Javier; Tangarife, Tomás; Cao, Francisco J.
2016-01-01
Efficiency at maximum power is found to be of the same order for a feedback ratchet and for its open-loop counterpart. However, feedback increases the output power up to a factor of five. This increase in output power is due to the increase in energy input and the effective entropy reduction obtained as a consequence of feedback. Optimal efficiency at maximum power is reached for time intervals between feedback actions two orders of magnitude smaller than the characteristic time of diffusion over a ratchet period length. The efficiency is computed consistently taking into account the correlation between the control actions. We consider a feedback control protocol for a discrete feedback flashing ratchet, which works against an external load. We maximize the power output optimizing the parameters of the ratchet, the controller, and the external load. The maximum power output is found to be upper bounded, so the attainable extracted power is limited. After, we compute an upper bound for the efficiency of this isothermal feedback ratchet at maximum power output. We make this computation applying recent developments of the thermodynamics of feedback-controlled systems, which give an equation to compute the entropy reduction due to information. However, this equation requires the computation of the probability of each of the possible sequences of the controller's actions. This computation becomes involved when the sequence of the controller's actions is non-Markovian, as is the case in most feedback ratchets. We here introduce an alternative procedure to set strong bounds to the entropy reduction in order to compute its value. In this procedure the bounds are evaluated in a quasi-Markovian limit, which emerge when there are big differences between the stationary probabilities of the system states. These big differences are an effect of the potential strength, which minimizes the departures from the Markovianicity of the sequence of control actions, allowing also to
Estimating a percent reduction in load
Millard, Steven P.
This article extends the work of Cohn et al. [1989] on estimating constituent loads to the problem of estimating a percent reduction in load. Three estimators are considered: the maximum likelihood (MLE), a ``bias-corrected'' maximum likelihood (BCMLE), and the minimum variance unbiased (MVUE). In terms of root-mean-square error, both the MVUE and BCMLE are superior to the MLE, and for the cases considered here there is no appreciable difference between the MVUE and the BCMLE. The BCMLE is constructed from quantities computed by most regression packages and is therefore simpler to compute than the MVUE (which involves approximating an infinite series). All three estimators are applied to a case study in which an agricultural tax in the Everglades agricultural area is tied to an observed percent reduction in phosphorus load. For typical hydrological data, very large sample sizes (of the order of 100 observations each in the baseline period and after) are required to estimate a percent reduction in load with reasonable precision.
Stabilization of Externally Slung Helicopter Loads
1974-08-01
maximum slir^ Loao weighting and " vertical bounce ." The last question provides information on multi-point suspension of external 1oads. PHASE...an allowable cargo load, and vertical bounce . 110 Maximum Sling Load Weight The maximum sling load lifted by a CH-47B helicopter under...changes were made in their flying technique except for very smooth flight control inputs when lifting an ACL. Vertical Bounce Fifteen of the forty Army
Valgas, Helio Moreira; Pinto, Roberto del Giudice R.; Franca, Carlos [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Lambert-Torres, Germano; Silva, Alexandre P. Alves da; Pires, Robson Celso; Costa Junior, Roberto Affonso [Escola Federal de Engenharia de Itajuba, MG (Brazil)
1994-12-31
Accurate dynamic load models allow more precise calculations of power system controls and stability limits, which are critical mainly in the operation planning of power systems. This paper describes the development of a computer program (software) for static and dynamic load model studies using the measurement approach for the CEMIG system. Two dynamic load model structures are developed and tested. A procedure for applying a set of measured data from an on-line transient recording system to develop load models is described. (author) 6 refs., 17 figs.
Duval, R. W.; Bahrami, M.
1985-01-01
The Rotor Systems Research Aircraft uses load cells to isolate the rotor/transmission systm from the fuselage. A mathematical model relating applied rotor loads and inertial loads of the rotor/transmission system to the load cell response is required to allow the load cells to be used to estimate rotor loads from flight data. Such a model is derived analytically by applying a force and moment balance to the isolated rotor/transmission system. The model is tested by comparing its estimated values of applied rotor loads with measured values obtained from a ground based shake test. Discrepancies in the comparison are used to isolate sources of unmodeled external loads. Once the structure of the mathematical model has been validated by comparison with experimental data, the parameters must be identified. Since the parameters may vary with flight condition it is desirable to identify the parameters directly from the flight data. A Maximum Likelihood identification algorithm is derived for this purpose and tested using a computer simulation of load cell data. The identification is found to converge within 10 samples. The rapid convergence facilitates tracking of time varying parameters of the load cell model in flight.
Finite element analysis for dental implants subjected to thermal loads
Mohamad Reza Khalili
2013-10-01
Full Text Available Background and Aims: Dental implants have been studied for replacement of missing teeth for many years. Productivity of implants is extremely related to the stability and resistance under applied loads and the minimum stress in jaw bone. The purpose of this study was to study numerically the 3D model of implant under thermal loads. Materials and Methods: Bone and the ITI implant were modeled in “Solidworks” software. To obtain the exact model, the bone was assumed as a linear orthotropic material. The implant system, including implant, abutment, framework and crown were modeled and located in the bone. After importing the model in Abaqus software, the material properties and boundary conditions and loads were applied and after meshing, the model was analyzed. In this analysis, the loads were applied in two steps. In the first step, the mechanical load was applied as tightening torque to the abutment and the abutment was tightened in the implant with 35 N.cm torque. In the second step, the thermal load originated from drinking cold and hot water was applied as thermal flux on the ceramic crown surface in this model. Results: Thermal analysis results showed that the thermal gradient in the bone was about 5.5 and 4.9 degrees of centigrade in the case of drinking cold and hot water respectively , although the maximum gradient of the whole system was reduced to 14 degrees, which occurred, in the crown by drinking cold water. Conclusion Thermal stresses were so small and it was because of the low thermal gradient. Maximum stresses occurred in the abutment were due to the tension preloads which were originated from the tightening torque.
Power and impulse applied during push press exercise.
Lake, Jason P; Mundy, Peter D; Comfort, Paul
2014-09-01
The aim of this study was to quantify the load, which maximized peak and mean power, and impulse applied to these loads, during the push press and to compare them to equivalent jump squat data. Resistance-trained men performed 2 push press (n = 17; age: 25.4 ± 7.4 years; height: 183.4 ± 5 cm; body mass: 87 ± 15.6 kg) and jump squat (n = 8 of original 17; age: 28.7 ± 8.1 years; height: 184.3 ± 5.5 cm; mass: 98 ± 5.3 kg) singles with 10-90% of their push press and back squat 1 repetition maximum (1RM), respectively, in 10% 1RM increments while standing on a force platform. Push press peak and mean power was maximized with 75.3 ± 16.4 and 64.7 ± 20% 1RM, respectively, and impulses applied to these loads were 243 ± 29 N·s and 231 ± 36 N·s. Increasing and decreasing load, from the load that maximized peak and mean power, by 10 and 20% 1RM reduced peak and mean power by 6-15% (p ≤ 0.05). Push press and jump squat maximum peak power (7%, p = 0.08) and the impulse that was applied to the load that maximized peak (8%, p = 0.17) and mean (13%, p = 0.91) power were not significantly different, but push press maximum mean power was significantly greater than the jump squat equivalent (∼9.5%, p = 0.03). The mechanical demand of the push press is comparable with the jump squat and could provide a time-efficient combination of lower-body power and upper-body and trunk strength training.
巴塔西; 于哲峰; 汪海
2013-01-01
A method was proposed for the global strain prediction of the composite laminate with special delaminations when the local buckling occurs.It was presented that the critical force of delamination buckling is determined by the maximum flexural stiffness of the sub-laminates in the delaminated region,so if two delaminations of same size have the same maximum sub-laminate flexural stiffness,their critical buckling force must be equal to each other.With the critical buckling force of a certain sub-laminate known,the loads on the debonded layer and intact layers were calculated using their axial stiffness.With the total load the global strain of the laminate was obtained when the local buckling occurs.Then,the three dimension finite element(FE)models of composite laminate with delamination of different area,depth and location were developed with ABAQUS,which are employed to simulate local buckling under quasi-static loading.The obtained delamination buckling loads compliance with above assumption.The proposed method was used to prediction global strain when the delamination buckling occurs,which agrees with those of FE well.Hence this method can be used to set up the samples for delamination depth detection.%提出了一种预测含特定分层损伤层压板发生局部屈曲时整体应变的方法.认为含分层子板的局部屈曲载荷由其弯曲刚度最大的分层决定,因而含有相同最大弯曲刚度分层的不同子板具有相同的屈曲载荷.在已知弯曲刚度最大分层的屈曲载荷的情况下,根据层压板的轴向刚度公式,计算出发生局部屈曲时弯曲刚度最大的分层与完好的基板分别承受的载荷,即得到总载荷,进而得到层压板的整体应变.用ABAQUS有限元分析软件建立含分层损伤的层压板模型,使用准静态加载进行了多种分层深度和分层位置下的局部屈曲仿真,所得局部屈曲载荷符合上述推论.用所提方法预测发生局部屈曲时的整体应变,结
Maximum Throughput in Multiple-Antenna Systems
Zamani, Mahdi
2012-01-01
The point-to-point multiple-antenna channel is investigated in uncorrelated block fading environment with Rayleigh distribution. The maximum throughput and maximum expected-rate of this channel are derived under the assumption that the transmitter is oblivious to the channel state information (CSI), however, the receiver has perfect CSI. First, we prove that in multiple-input single-output (MISO) channels, the optimum transmission strategy maximizing the throughput is to use all available antennas and perform equal power allocation with uncorrelated signals. Furthermore, to increase the expected-rate, multi-layer coding is applied. Analogously, we establish that sending uncorrelated signals and performing equal power allocation across all available antennas at each layer is optimum. A closed form expression for the maximum continuous-layer expected-rate of MISO channels is also obtained. Moreover, we investigate multiple-input multiple-output (MIMO) channels, and formulate the maximum throughput in the asympt...
The strong maximum principle revisited
Pucci, Patrizia; Serrin, James
In this paper we first present the classical maximum principle due to E. Hopf, together with an extended commentary and discussion of Hopf's paper. We emphasize the comparison technique invented by Hopf to prove this principle, which has since become a main mathematical tool for the study of second order elliptic partial differential equations and has generated an enormous number of important applications. While Hopf's principle is generally understood to apply to linear equations, it is in fact also crucial in nonlinear theories, such as those under consideration here. In particular, we shall treat and discuss recent generalizations of the strong maximum principle, and also the compact support principle, for the case of singular quasilinear elliptic differential inequalities, under generally weak assumptions on the quasilinear operators and the nonlinearities involved. Our principal interest is in necessary and sufficient conditions for the validity of both principles; in exposing and simplifying earlier proofs of corresponding results; and in extending the conclusions to wider classes of singular operators than previously considered. The results have unexpected ramifications for other problems, as will develop from the exposition, e.g. two point boundary value problems for singular quasilinear ordinary differential equations (Sections 3 and 4); the exterior Dirichlet boundary value problem (Section 5); the existence of dead cores and compact support solutions, i.e. dead cores at infinity (Section 7); Euler-Lagrange inequalities on a Riemannian manifold (Section 9); comparison and uniqueness theorems for solutions of singular quasilinear differential inequalities (Section 10). The case of p-regular elliptic inequalities is briefly considered in Section 11.
Maximum Likelihood Estimation of Search Costs
J.L. Moraga-Gonzalez (José Luis); M.R. Wildenbeest (Matthijs)
2006-01-01
textabstractIn a recent paper Hong and Shum (forthcoming) present a structural methodology to estimate search cost distributions. We extend their approach to the case of oligopoly and present a maximum likelihood estimate of the search cost distribution. We apply our method to a data set of online p
Simon eWalker
2016-04-01
Full Text Available 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 versus traditional isoinertial resistance training in strength-trained men. Young (22±3 y, 177±6 cm, 76±10 kg, n = 28 strength-trained men (2.6±2.2 y 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 ultrasound 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
Kock, Carsten Weber; Vesth, Allan
The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regarding...... the fatigue loads, the rotor, blades and tower moments are presented. The fatigue loads are evaluated using rainflow counting described in detail in Ref. [1]. The 1Hz equivalent load ranges are calculated at different wind speeds. All information regarding the instrumentation is collected in [ref 4] and [ref...
Simone Bittencourt
2006-06-01
Full Text Available Para implementação e operacionalização da política brasileira de recursos hídricos, é imprescindível o uso de ferramentas de planejamento que considerem o efeito de todas as atividades ou processos que causam ou contribuem para a degradação da qualidade de um corpo d'água. Neste sentido, aplicou-se o processo TMDL (total maximum daily load, desenvolvido pela Agência de Proteção Ambiental dos Estados Unidos (EPA, para o P, na área de drenagem de contribuição ao futuro reservatório Piraquara II, bacia hidrográfica do rio Piraquara, Paraná. O processo TMDL determina a quantidade máxima de cargas de um poluente que um corpo d'água pode receber sem violar os padrões estabelecidos de qualidade da água e aloca cargas deste poluente entre fontes de poluição pontuais e difusas. No presente estudo, utilizou-se o método TMDL, com o objetivo de demonstrar ser ele uma ferramenta útil no processo de gestão dos recursos hídricos. Simularam-se cenários de uso do solo, por meio de modelagem matemática, até obter-se uma concentração de P total no reservatório abaixo da faixa limite para ocorrência de eutrofização, de 0,025 a 0,10 mg L-1, estabelecida no estudo. Realizou-se uma simulação de uso atual do solo, visando prever a condição inicial de qualidade da água no corpo d'água, na qual a concentração de P total no reservatório resultante não atendeu ao padrão estabelecido. Procedeu-se a uma segunda simulação com adoção das medidas de controle, recomposição de mata ciliar e plantio direto, para reduzir a exportação de carga de P total da bacia. Obteve-se uma melhoria na qualidade da água do reservatório, indicando que as medidas adotadas foram suficientes para atingir o padrão estabelecido, o que demonstra a aplicabilidade do método.For the implementation and operation of the Brazilian Federal law on water resources of 1997 it is indispensable to use planning tools that take into account the effect of
Maximum entropy production in daisyworld
Maunu, Haley A.; Knuth, Kevin H.
2012-05-01
Daisyworld was first introduced in 1983 by Watson and Lovelock as a model that illustrates how life can influence a planet's climate. These models typically involve modeling a planetary surface on which black and white daisies can grow thus influencing the local surface albedo and therefore also the temperature distribution. Since then, variations of daisyworld have been applied to study problems ranging from ecological systems to global climate. Much of the interest in daisyworld models is due to the fact that they enable one to study self-regulating systems. These models are nonlinear, and as such they exhibit sensitive dependence on initial conditions, and depending on the specifics of the model they can also exhibit feedback loops, oscillations, and chaotic behavior. Many daisyworld models are thermodynamic in nature in that they rely on heat flux and temperature gradients. However, what is not well-known is whether, or even why, a daisyworld model might settle into a maximum entropy production (MEP) state. With the aim to better understand these systems, this paper will discuss what is known about the role of MEP in daisyworld models.
Vesth, Allan; Kock, Carsten Weber
The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regardi...
Kock, Carsten Weber; Vesth, Allan
The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regarding...
Probability Based Evaluation of Vehicular Bridge Load using Weigh-in-Motion Data
Widi Nugraha
2016-02-01
Full Text Available Load and Resistance Factored Design (LRFD method for designing bridge in Indonesia have been implemented for more than 25 years. LRFD method treating loads and strengths variables as random variables with specific safety factors for different loads and strengths variables type. The nominal loads, load factors, reduction factors, and other criteria for bridge design code can be determined to meet the reliability criteria. Statistical data of weigh-in-motion (WIM vehicular loads measurement in Northern Java highway, Cikampek - Pamanukan, West Java (2011, used in as statistical loads variable. A 25 m simple span bridge with reinforced concrete T-girder is used as a model for structural analysis due to WIM measured and nominal vehicular load based on RSNI T-02-2005, with applied bending moment of girder as the output. The distribution fitting result of applied bending moment due to WIM measured vehicular loads is lognormal. The maximum bending moment due to RSNI T-02-2005 nominal vehicular load is 842.45 kN-m and has probability of exceedance of 5x10-5. It can be concluded, for this study, that the bridge designed using RSNI T-02-2005 is safely designed, since it has reliability index, β of 5.02, higher than target reliability, β ranging from 3.50 or 3.72.
Armando Jaime Ustariz-Farfan
2012-08-01
Full Text Available El interés creciente de utilizar filtros activos de potencia para compensar las corrientes no sinusoidales producidas por las cargas no lineales ha aumentado el uso de la teoría instantánea de potencia reactiva. Sin embargo, esta teoría se puede aplicar solamente a los sistemas trifásicos de tres o cuatro conductores. Este artículo presenta una nueva definición de la potencia instantánea que puede ser aplicada a todos los sistemas polifásicos. Así, el concepto de producto tensorial es introducido para definir el tensor instantáneo de potencia y también la descomposición de la corriente en las componentes activas y reactivas sin importar el número de fases del sistema eléctrico. Finalmente, un análisis exhaustivo de casos prácticos se ha realizado a nivel de simulación, los cuales han permitido que el enfoque propuesto sea verificado.The use of the instantaneous reactive power theory is greater than before due to the increased interest to use active power filters to compensate the non-sinusoidal currents produced by nonlinear loads. However, this theory can only be applied to three-phase systems of three or four conductors. This paper presents a new definition of instantaneous power that can be applied to all multiphase systems. Thus, the concept of tensor product is introduced to define the instantaneous power tensor and also the current decomposition in active and reactive components regardless of the number of phases of the power system. Finally, an exhaustive analysis of practical cases has been carried out at a simulation level which verified the proposed approach.
The maximum force in a column under constant speed compression
Kuzkin, Vitaly A
2015-01-01
Dynamic buckling of an elastic column under compression at constant speed is investigated assuming the first-mode buckling. Two cases are considered: (i) an imperfect column (Hoff's statement), and (ii) a perfect column having an initial lateral deflection. The range of parameters, where the maximum load supported by a column exceeds Euler static force is determined. In this range, the maximum load is represented as a function of the compression rate, slenderness ratio, and imperfection/initial deflection. Considering the results we answer the following question: "How slowly the column should be compressed in order to measure static load-bearing capacity?" This question is important for the proper setup of laboratory experiments and computer simulations of buckling. Additionally, it is shown that the behavior of a perfect column having an initial deflection differ significantlys form the behavior of an imperfect column. In particular, the dependence of the maximum force on the compression rate is non-monotoni...
Vestige: Maximum likelihood phylogenetic footprinting
Maxwell Peter
2005-05-01
Full Text Available Abstract Background Phylogenetic footprinting is the identification of functional regions of DNA by their evolutionary conservation. This is achieved by comparing orthologous regions from multiple species and identifying the DNA regions that have diverged less than neutral DNA. Vestige is a phylogenetic footprinting package built on the PyEvolve toolkit that uses probabilistic molecular evolutionary modelling to represent aspects of sequence evolution, including the conventional divergence measure employed by other footprinting approaches. In addition to measuring the divergence, Vestige allows the expansion of the definition of a phylogenetic footprint to include variation in the distribution of any molecular evolutionary processes. This is achieved by displaying the distribution of model parameters that represent partitions of molecular evolutionary substitutions. Examination of the spatial incidence of these effects across regions of the genome can identify DNA segments that differ in the nature of the evolutionary process. Results Vestige was applied to a reference dataset of the SCL locus from four species and provided clear identification of the known conserved regions in this dataset. To demonstrate the flexibility to use diverse models of molecular evolution and dissect the nature of the evolutionary process Vestige was used to footprint the Ka/Ks ratio in primate BRCA1 with a codon model of evolution. Two regions of putative adaptive evolution were identified illustrating the ability of Vestige to represent the spatial distribution of distinct molecular evolutionary processes. Conclusion Vestige provides a flexible, open platform for phylogenetic footprinting. Underpinned by the PyEvolve toolkit, Vestige provides a framework for visualising the signatures of evolutionary processes across the genome of numerous organisms simultaneously. By exploiting the maximum-likelihood statistical framework, the complex interplay between mutational
Determination of maximum power transfer conditions of bimorph piezoelectric energy harvesters
Ahmad, Mahmoud Al
2012-07-23
In this paper, a method to find the maximum power transfer conditions in bimorph piezoelectric-based harvesters is proposed. Explicitly, we derive a closed form expression that relates the load resistance to the mechanical parameters describing the bimorph based on the electromechanical, single degree of freedom, analogy. Further, by taking into account the intrinsic capacitance of the piezoelectric harvester, a more descriptive expression of the resonant frequency in piezoelectric bimorphs was derived. In interest of impartiality, we apply the proposed philosophy on previously published experimental results and compare it with other reported hypotheses. It was found that the proposed method was able to predict the actual optimum load resistance more accurately than other methods reported in the literature. © 2012 American Institute of Physics.
14 CFR 25.343 - Design fuel and oil loads.
2010-01-01
... Design fuel and oil loads. (a) The disposable load combinations must include each fuel and oil load in the range from zero fuel and oil to the selected maximum fuel and oil load. A structural reserve fuel... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Design fuel and oil loads. 25.343...
Zipf's law, power laws and maximum entropy
Visser, Matt
2013-04-01
Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.
Zipf's law, power laws, and maximum entropy
Visser, Matt
2012-01-01
Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines - from astronomy to demographics to economics to linguistics to zoology, and even warfare. A recent model of random group formation [RGF] attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present article I argue that the cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.
Load research and load estimation in electricity distribution
Seppaelae, A. [VTT Energy, Espoo (Finland). Energy Systems
1996-12-31
The topics introduced in this thesis are: the Finnish load research project, a simple form customer class load model, analysis of the origins of customers load distribution, a method for the estimation of the confidence interval of customer loads and Distribution Load Estimation (DLE) which utilises both the load models and measurements from distribution networks. The Finnish load research project started in 1983. The project was initially coordinated by the Association of Finnish Electric Utilities and 40 utilities joined the project. Now there are over 1000 customer hourly load recordings in a database. A simple form customer class load model is introduced. The model is designed to be practical for most utility applications and has been used by the Finnish utilities for several years. The only variable of the model is the customers annual energy consumption. The model gives the customers average hourly load and standard deviation for a selected month, day and hour. The statistical distribution of customer loads is studied and a model for customer electric load variation is developed. The model results in a lognormal distribution as an extreme case. Using the `simple form load model`, a method for estimating confidence intervals (confidence limits) of customer hourly load is developed. The two methods selected for final analysis are based on normal and lognormal distribution estimated in a simplified manner. The estimation of several cumulated customer class loads is also analysed. Customer class load estimation which combines the information from load models and distribution network load measurements is developed. This method, called Distribution Load Estimation (DLE), utilises information already available in the utilities databases and is thus easy to apply
Maximum Photovoltaic Penetration Levels on Typical Distribution Feeders: Preprint
Hoke, A.; Butler, R.; Hambrick, J.; Kroposki, B.
2012-07-01
This paper presents simulation results for a taxonomy of typical distribution feeders with various levels of photovoltaic (PV) penetration. For each of the 16 feeders simulated, the maximum PV penetration that did not result in steady-state voltage or current violation is presented for several PV location scenarios: clustered near the feeder source, clustered near the midpoint of the feeder, clustered near the end of the feeder, randomly located, and evenly distributed. In addition, the maximum level of PV is presented for single, large PV systems at each location. Maximum PV penetration was determined by requiring that feeder voltages stay within ANSI Range A and that feeder currents stay within the ranges determined by overcurrent protection devices. Simulations were run in GridLAB-D using hourly time steps over a year with randomized load profiles based on utility data and typical meteorological year weather data. For 86% of the cases simulated, maximum PV penetration was at least 30% of peak load.
The maximum rotation of a galactic disc
Bottema, R
1997-01-01
The observed stellar velocity dispersions of galactic discs show that the maximum rotation of a disc is on average 63% of the observed maximum rotation. This criterion can, however, not be applied to small or low surface brightness (LSB) galaxies because such systems show, in general, a continuously rising rotation curve until the outermost measured radial position. That is why a general relation has been derived, giving the maximum rotation for a disc depending on the luminosity, surface brightness, and colour of the disc. As a physical basis of this relation serves an adopted fixed mass-to-light ratio as a function of colour. That functionality is consistent with results from population synthesis models and its absolute value is determined from the observed stellar velocity dispersions. The derived maximum disc rotation is compared with a number of observed maximum rotations, clearly demonstrating the need for appreciable amounts of dark matter in the disc region and even more so for LSB galaxies. Matters h...
Maximum Profit Configurations of Commercial Engines
Yiran Chen
2011-01-01
An investigation of commercial engines with finite capacity low- and high-price economic subsystems and a generalized commodity transfer law [n ∝ Δ (P m)] in commodity flow processes, in which effects of the price elasticities of supply and demand are introduced, is presented in this paper. Optimal cycle configurations of commercial engines for maximum profit are obtained by applying optimal control theory. In some special cases, the eventual state—market equilibrium—is solely determined by t...
OECD Maximum Residue Limit Calculator
With the goal of harmonizing the calculation of maximum residue limits (MRLs) across the Organisation for Economic Cooperation and Development, the OECD has developed an MRL Calculator. View the calculator.
Loading Rate for Modulus of Rupture Test
QUMing; ZHANGYong－fang
1996-01-01
Relationship among load rate,strain rate and stress rate for modulus of ruptue test,the way of applying load with stress rate using both hydraulic compression testing machine and nechanical compression testing machine have been described.The test results are identical with selected strain rate loading and stress rate loading.
Frandsen, S.; Tarp Johansen, N.J.; Joergensen, H. [Forskningscenter Risoe, Roskilde (Denmark); Gravesen, H.; Soerensen, S.L. [Carl Bro, Glostrup (Denmark); Pedersen, J. [Elsam Engineering, Fredericia (Denmark); Zorn, R.; Hvidberg Knudsen, M. [DHI Water and Environment, Hoersholm (Denmark); Voelund, P. [Energi E2, Koebenhavn (Denmark)
2003-09-01
data, wind and temperature data from the NCAR/NCEP reanalysis data have been included for 6 grid points in Denmark (in a 2.5 degree grid resolution). The data represents 10 meter avinds and 2 meter temperatures four times daily since 1948 until 2001. A simple design procedure for foundations of offshore wind turbines has been developed. It includes a) Extreme loads, b) Maximum operational loads and c) Extreme ice load combined With associated operational loads. It has been outlined how to determine relevant partial coefficients, the advantage of a quadratic composition rule compared with a linear load composition, how to include dynamic interaction betaveen wind and wave loads, and finally it was found that the torque load is not correlated With the overturning moment and the shear force. (au)
段其昌; 唐若笠; 隆霞
2012-01-01
将标准粒子群优化算法中的速度惯性、粒子个体的记忆因素和粒子间学习交流因素等几个特征引入人工鱼群算法,提出了粒子群优化鱼群算法.在新算法中,鱼群的游动具有了速度惯性的特征,并且其行为模式被扩充为追尾、聚群、记忆、交流以及觅食.通过仿真分析,验证了粒子群优化鱼群算法比两种基本算法具有更快的收敛速度和更高的寻优精度,且性能稳定.最后将所提出的粒子群优化鱼群算法应用于局部遮阴情况下的光伏发电系统最大功率点跟踪,实验表明,该算法可以在很短时间内以很高精度寻得不均匀光照系统的最大功率点.%Introducing the velocity inertia, memory capacity of each individual and learning or communicating capacity of Particle Swarm Optimization ( PSO) into the Artificial Fish-Swarm Algorithm (AFSA), a new algorithm called the "Fish-Swarm Algorithm optimized by PSO( PSO-FSA)" was put forward. In this new algorithm, the swimming of each fish has velocity inertia, and the PSO-FSA has totally five kinds of behavior pattern as follows: swarming, following, remembering, communicating and searching. The simulation analysis shows that PSO-FSA has more stable and higher performance in convergence speed and searching precision than PSO and AFSA. Finally, the PSO-FSA was applied to the maximum power point tracking of photovoltaic power generation system under partially shaded condition, and the experimental results show that PSO-FSA can find the maximum power point under partially shaded insolation conditions quickly and precisely.
Muhammad Abid
2010-11-01
Full Text Available In this paper result of an extensive comparative experimental study of a gasketed and non-gasketed flange joint with different assemblies with different combined load combinations is carried out to investigate joint performance i.e. joint strength and sealing capability. Actual joint load capacities are determined under both the design and proof test pressure with maximum additional external loading (axial and bending that can be applied for safe joint performance. In addition, application of combined load is also discussed in the light of equivalent pressure approach.
Maximum margin Bayesian network classifiers.
Pernkopf, Franz; Wohlmayr, Michael; Tschiatschek, Sebastian
2012-03-01
We present a maximum margin parameter learning algorithm for Bayesian network classifiers using a conjugate gradient (CG) method for optimization. In contrast to previous approaches, we maintain the normalization constraints on the parameters of the Bayesian network during optimization, i.e., the probabilistic interpretation of the model is not lost. This enables us to handle missing features in discriminatively optimized Bayesian networks. In experiments, we compare the classification performance of maximum margin parameter learning to conditional likelihood and maximum likelihood learning approaches. Discriminative parameter learning significantly outperforms generative maximum likelihood estimation for naive Bayes and tree augmented naive Bayes structures on all considered data sets. Furthermore, maximizing the margin dominates the conditional likelihood approach in terms of classification performance in most cases. We provide results for a recently proposed maximum margin optimization approach based on convex relaxation. While the classification results are highly similar, our CG-based optimization is computationally up to orders of magnitude faster. Margin-optimized Bayesian network classifiers achieve classification performance comparable to support vector machines (SVMs) using fewer parameters. Moreover, we show that unanticipated missing feature values during classification can be easily processed by discriminatively optimized Bayesian network classifiers, a case where discriminative classifiers usually require mechanisms to complete unknown feature values in the data first.
Fang, W.; Quan, S. H.; Xie, C. J.; Tang, X. F.; Wang, L. L.; Huang, L.
2016-03-01
In this study, a direct-current/direct-current (DC/DC) converter with maximum power point tracking (MPPT) is developed to down-convert the high voltage DC output from a thermoelectric generator to the lower voltage required to charge batteries. To improve the tracking accuracy and speed of the converter, a novel MPPT control scheme characterized by an aggregated dichotomy and gradient (ADG) method is proposed. In the first stage, the dichotomy algorithm is used as a fast search method to find the approximate region of the maximum power point. The gradient method is then applied for rapid and accurate tracking of the maximum power point. To validate the proposed MPPT method, a test bench composed of an automobile exhaust thermoelectric generator was constructed for harvesting the automotive exhaust heat energy. Steady-state and transient tracking experiments under five different load conditions were carried out using a DC/DC converter with the proposed ADG and with three traditional methods. The experimental results show that the ADG method can track the maximum power within 140 ms with a 1.1% error rate when the engine operates at 3300 rpm@71 NM, which is superior to the performance of the single dichotomy method, the single gradient method and the perturbation and observation method from the viewpoint of improved tracking accuracy and speed.
Maximum-entropy description of animal movement.
Fleming, Chris H; Subaşı, Yiğit; Calabrese, Justin M
2015-03-01
We introduce a class of maximum-entropy states that naturally includes within it all of the major continuous-time stochastic processes that have been applied to animal movement, including Brownian motion, Ornstein-Uhlenbeck motion, integrated Ornstein-Uhlenbeck motion, a recently discovered hybrid of the previous models, and a new model that describes central-place foraging. We are also able to predict a further hierarchy of new models that will emerge as data quality improves to better resolve the underlying continuity of animal movement. Finally, we also show that Langevin equations must obey a fluctuation-dissipation theorem to generate processes that fall from this class of maximum-entropy distributions when the constraints are purely kinematic.
Pareto versus lognormal: a maximum entropy test.
Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano
2011-08-01
It is commonly found that distributions that seem to be lognormal over a broad range change to a power-law (Pareto) distribution for the last few percentiles. The distributions of many physical, natural, and social events (earthquake size, species abundance, income and wealth, as well as file, city, and firm sizes) display this structure. We present a test for the occurrence of power-law tails in statistical distributions based on maximum entropy. This methodology allows one to identify the true data-generating processes even in the case when it is neither lognormal nor Pareto. The maximum entropy approach is then compared with other widely used methods and applied to different levels of aggregation of complex systems. Our results provide support for the theory that distributions with lognormal body and Pareto tail can be generated as mixtures of lognormally distributed units.
Nonparametric Maximum Entropy Estimation on Information Diagrams
Martin, Elliot A; Meinke, Alexander; Děchtěrenko, Filip; Davidsen, Jörn
2016-01-01
Maximum entropy estimation is of broad interest for inferring properties of systems across many different disciplines. In this work, we significantly extend a technique we previously introduced for estimating the maximum entropy of a set of random discrete variables when conditioning on bivariate mutual informations and univariate entropies. Specifically, we show how to apply the concept to continuous random variables and vastly expand the types of information-theoretic quantities one can condition on. This allows us to establish a number of significant advantages of our approach over existing ones. Not only does our method perform favorably in the undersampled regime, where existing methods fail, but it also can be dramatically less computationally expensive as the cardinality of the variables increases. In addition, we propose a nonparametric formulation of connected informations and give an illustrative example showing how this agrees with the existing parametric formulation in cases of interest. We furthe...
Filippo Cassarà
2013-03-01
Full Text Available Recent research addressed the main role of hepcidin in the regulation of iron metabolism. However, while this mechanism could be relevant in causing iron load in Thalassemia Intermedia and Sickle-Cell Anemia, its role in Thalassemia Major (TM is marginal. This is mainly due to the high impact of transfusional requirement into the severe increase of body iron. Moreover, the damage of iron load may be worsened by infections, as HCV hepatitis, or liver and endocrinological damage. One of the most relevant associations was found between splenectomy and increase of risk for mortality due,probably, to more severe iron load. These issues suggest as morbidity and mortality of this group of patients they do not depend only by our ability in controlling heart damage but even in preventing or treating particular infections and complications. This finding is supported by the impairment of survival curves in patients with complications different from heart damage. However, because, during recent years different direct and indirect methods to detect iron overload in patients affected by secondary hemochromatosis have been implemented, our ability to maintain under control iron load is significantly improved. Anyway, the future in iron load management remains to be able to have an iron load map of our body for targeting chelation and other medical treatment according to the single organ damage.
Greenslade, Thomas B., Jr.
1985-01-01
Discusses a series of experiments performed by Thomas Hope in 1805 which show the temperature at which water has its maximum density. Early data cast into a modern form as well as guidelines and recent data collected from the author provide background for duplicating Hope's experiments in the classroom. (JN)
Integer Programming Model for Maximum Clique in Graph
YUAN Xi-bo; YANG You; ZENG Xin-hai
2005-01-01
The maximum clique or maximum independent set of graph is a classical problem in graph theory. Combined with Boolean algebra and integer programming, two integer programming models for maximum clique problem,which improve the old results were designed in this paper. Then, the programming model for maximum independent set is a corollary of the main results. These two models can be easily applied to computer algorithm and software, and suitable for graphs of any scale. Finally the models are presented as Lingo algorithms, verified and compared by several examples.
CORA: Emission Line Fitting with Maximum Likelihood
Ness, Jan-Uwe; Wichmann, Rainer
2011-12-01
CORA analyzes emission line spectra with low count numbers and fits them to a line using the maximum likelihood technique. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise, the software derives the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. CORA has been applied to an X-ray spectrum with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory.
Hosseini-Bioki, M. M.; Rashidinejad, M.; Abdollahi, A.
2013-11-01
Load shedding is a crucial issue in power systems especially under restructured electricity environment. Market-driven load shedding in reregulated power systems associated with security as well as reliability is investigated in this paper. A technoeconomic multi-objective function is introduced to reveal an optimal load shedding scheme considering maximum social welfare. The proposed optimization problem includes maximum GENCOs and loads' profits as well as maximum loadability limit under normal and contingency conditions. Particle swarm optimization (PSO) as a heuristic optimization technique, is utilized to find an optimal load shedding scheme. In a market-driven structure, generators offer their bidding blocks while the dispatchable loads will bid their price-responsive demands. An independent system operator (ISO) derives a market clearing price (MCP) while rescheduling the amount of generating power in both pre-contingency and post-contingency conditions. The proposed methodology is developed on a 3-bus system and then is applied to a modified IEEE 30-bus test system. The obtained results show the effectiveness of the proposed methodology in implementing the optimal load shedding satisfying social welfare by maintaining voltage stability margin (VSM) through technoeconomic analyses.
Progressive collapse resisting capacity of reinforced concrete load bearing wall structures
Alireza Rahai; Alireza Shahin; Farzad Hatami
2015-01-01
Reinforced concrete (RC) load bearing wall is widely used in high-rise and mid-rise buildings. Due to the number of walls in plan and reduction in lateral force portion, this system is not only stronger against earthquakes, but also more economical. The effect of progressive collapse caused by removal of load bearing elements, in various positions in plan and stories of the RC load bearing wall system was evaluated by nonlinear dynamic and static analyses. For this purpose, three-dimensional model of 10-story structure was selected. The analysis results indicated stability, strength and stiffness of the RC load-bearing wall system against progressive collapse. It was observed that the most critical condition for removal of load bearing walls was the instantaneous removal of the surrounding walls located at the corners of the building where the sections of the load bearing elements were changed. In this case, the maximum vertical displacement was limited to 6.3 mm and the structure failed after applying the load of 10 times the axial load bored by removed elements. Comparison between the results of the nonlinear dynamic and static analyses demonstrated that the “load factor” parameter was a reasonable criterion to evaluate the progressive collapse potential of the structure.
Gamp, Alexander
2013-01-01
We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.
The maximum rate of mammal evolution
Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.
2012-03-01
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.
The maximum rate of mammal evolution
Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.
2012-01-01
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous–Paleogene (K–Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes. PMID:22308461
The maximum rate of mammal evolution.
Evans, Alistair R; Jones, David; Boyer, Alison G; Brown, James H; Costa, Daniel P; Ernest, S K Morgan; Fitzgerald, Erich M G; Fortelius, Mikael; Gittleman, John L; Hamilton, Marcus J; Harding, Larisa E; Lintulaakso, Kari; Lyons, S Kathleen; Okie, Jordan G; Saarinen, Juha J; Sibly, Richard M; Smith, Felisa A; Stephens, Patrick R; Theodor, Jessica M; Uhen, Mark D
2012-03-13
How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.
Maximum Genus of Strong Embeddings
Er-ling Wei; Yan-pei Liu; Han Ren
2003-01-01
The strong embedding conjecture states that any 2-connected graph has a strong embedding on some surface. It implies the circuit double cover conjecture: Any 2-connected graph has a circuit double cover.Conversely, it is not true. But for a 3-regular graph, the two conjectures are equivalent. In this paper, a characterization of graphs having a strong embedding with exactly 3 faces, which is the strong embedding of maximum genus, is given. In addition, some graphs with the property are provided. More generally, an upper bound of the maximum genus of strong embeddings of a graph is presented too. Lastly, it is shown that the interpolation theorem is true to planar Halin graph.
Koutroulis, Eftichios; Blaabjerg, Frede
2012-01-01
output, such that it behaves as a constant input-power load. The proposed method has the advantage that it can be applied in either stand-alone or grid-connected PV systems comprising PV arrays with unknown electrical characteristics and does not require knowledge about the PV modules configuration......The power-voltage characteristic of photovoltaic (PV) arrays operating under partial-shading conditions exhibits multiple local maximum power points (MPPs). In this paper, a new method to track the global MPP is presented, which is based on controlling a dc/dc converter connected at the PV array...
Kimble, Michael C.; White, Ralph E.
1991-01-01
A mathematical model of a hydrogen/oxygen alkaline fuel cell is presented that can be used to predict the polarization behavior under various power loads. The major limitations to achieving high power densities are indicated and methods to increase the maximum attainable power density are suggested. The alkaline fuel cell model describes the phenomena occurring in the solid, liquid, and gaseous phases of the anode, separator, and cathode regions based on porous electrode theory applied to three phases. Fundamental equations of chemical engineering that describe conservation of mass and charge, species transport, and kinetic phenomena are used to develop the model by treating all phases as a homogeneous continuum.
Robust optimal sensor placement for operational modal analysis based on maximum expected utility
Li, Binbin; Der Kiureghian, Armen
2016-06-01
Optimal sensor placement is essentially a decision problem under uncertainty. The maximum expected utility theory and a Bayesian linear model are used in this paper for robust sensor placement aimed at operational modal identification. To avoid nonlinear relations between modal parameters and measured responses, we choose to optimize the sensor locations relative to identifying modal responses. Since the modal responses contain all the information necessary to identify the modal parameters, the optimal sensor locations for modal response estimation provide at least a suboptimal solution for identification of modal parameters. First, a probabilistic model for sensor placement considering model uncertainty, load uncertainty and measurement error is proposed. The maximum expected utility theory is then applied with this model by considering utility functions based on three principles: quadratic loss, Shannon information, and K-L divergence. In addition, the prior covariance of modal responses under band-limited white-noise excitation is derived and the nearest Kronecker product approximation is employed to accelerate evaluation of the utility function. As demonstration and validation examples, sensor placements in a 16-degrees-of-freedom shear-type building and in Guangzhou TV Tower under ground motion and wind load are considered. Placements of individual displacement meter, velocimeter, accelerometer and placement of mixed sensors are illustrated.
Remizov, Ivan D
2009-01-01
In this note, we represent a subdifferential of a maximum functional defined on the space of all real-valued continuous functions on a given metric compact set. For a given argument, $f$ it coincides with the set of all probability measures on the set of points maximizing $f$ on the initial compact set. This complete characterization lies in the heart of several important identities in microeconomics, such as Roy's identity, Sheppard's lemma, as well as duality theory in production and linear programming.
The Testability of Maximum Magnitude
Clements, R.; Schorlemmer, D.; Gonzalez, A.; Zoeller, G.; Schneider, M.
2012-12-01
Recent disasters caused by earthquakes of unexpectedly large magnitude (such as Tohoku) illustrate the need for reliable assessments of the seismic hazard. Estimates of the maximum possible magnitude M at a given fault or in a particular zone are essential parameters in probabilistic seismic hazard assessment (PSHA), but their accuracy remains untested. In this study, we discuss the testability of long-term and short-term M estimates and the limitations that arise from testing such rare events. Of considerable importance is whether or not those limitations imply a lack of testability of a useful maximum magnitude estimate, and whether this should have any influence on current PSHA methodology. We use a simple extreme value theory approach to derive a probability distribution for the expected maximum magnitude in a future time interval, and we perform a sensitivity analysis on this distribution to determine if there is a reasonable avenue available for testing M estimates as they are commonly reported today: devoid of an appropriate probability distribution of their own and estimated only for infinite time (or relatively large untestable periods). Our results imply that any attempt at testing such estimates is futile, and that the distribution is highly sensitive to M estimates only under certain optimal conditions that are rarely observed in practice. In the future we suggest that PSHA modelers be brutally honest about the uncertainty of M estimates, or must find a way to decrease its influence on the estimated hazard.
Alternative Multiview Maximum Entropy Discrimination.
Chao, Guoqing; Sun, Shiliang
2016-07-01
Maximum entropy discrimination (MED) is a general framework for discriminative estimation based on maximum entropy and maximum margin principles, and can produce hard-margin support vector machines under some assumptions. Recently, the multiview version of MED multiview MED (MVMED) was proposed. In this paper, we try to explore a more natural MVMED framework by assuming two separate distributions p1( Θ1) over the first-view classifier parameter Θ1 and p2( Θ2) over the second-view classifier parameter Θ2 . We name the new MVMED framework as alternative MVMED (AMVMED), which enforces the posteriors of two view margins to be equal. The proposed AMVMED is more flexible than the existing MVMED, because compared with MVMED, which optimizes one relative entropy, AMVMED assigns one relative entropy term to each of the two views, thus incorporating a tradeoff between the two views. We give the detailed solving procedure, which can be divided into two steps. The first step is solving our optimization problem without considering the equal margin posteriors from two views, and then, in the second step, we consider the equal posteriors. Experimental results on multiple real-world data sets verify the effectiveness of the AMVMED, and comparisons with MVMED are also reported.
Csernus, Marilyn
Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…
Van den Ende, D.; Almeida, P.M.R.; Dingemans, T.J.; Van der Zwaag, S.
2007-01-01
The invention relates to a load sensor comprising a polymer matrix and a piezo-ceramic material such as PZT, em not bedded in the polymer matrix, which together form a compos not ite, wherein the polymer matrix is a liquid crystalline resin, and wherein the piezo-ceramic material is a PZT powder for
Csernus, Marilyn
Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…
Johnson, Ken I.; Deibler, John E.; Karri, Naveen K.; Pilli, Siva P. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Julyk, Larry J. [M and D Professional Services, Inc., Richland, Washington 99352 (United States)
2012-07-01
dome, so the penetration does reduce the concentrated limit load somewhat. However, the safety factors comparing the limit loads to the maximum allowable applied loads remain well above the required value of 3.0. The buckling analysis method accounts for the geometric imperfections, concrete creep, cracking and reinforcements, and concrete plasticity in determining the allowable buckling load limits. The method was demonstrated in this paper for the evaluation of a tank before and after a penetration is added in the dome center. Finite element buckling models were used to accurately calculate the linear critical buckling loads. The models showed that adding the penetration reduces the linear critical buckling load by only 2.5%. Bounding cases also showed that the possible range of soil support on the walls does not significantly affect the dome buckling loads. Buckling models of the full 360 deg. dome also showed that the dome is more resistant to buckling when the load is offset than when it is positioned over the center. These limit load and buckling analysis methods are being used at the Hanford site to assess the tank loads that can be safely applied during future waste retrieval activities. (authors)
Peak loads and network investments in sustainable energy transitions
Blokhuis, Erik, E-mail: e.g.j.blokhuis@tue.nl [Eindhoven University of Technology, Department of Architecture, Building and Planning, Vertigo 8.11, P.O. Box 513, 5600MB Eindhoven (Netherlands); Brouwers, Bart [Eindhoven University of Technology, Department of Architecture, Building and Planning, Vertigo 8.11, P.O. Box 513, 5600MB Eindhoven (Netherlands); Putten, Eric van der [Endinet, Gas and Electricity Network Operations, P.O. Box 2005, 5600CA Eindhoven (Netherlands); Schaefer, Wim [Eindhoven University of Technology, Department of Architecture, Building and Planning, Vertigo 8.11, P.O. Box 513, 5600MB Eindhoven (Netherlands)
2011-10-15
Current energy distribution networks are often not equipped for facilitating expected sustainable transitions. Major concerns for future electricity networks are the possibility of peak load increases and the expected growth of decentralized energy generation. In this article, we focus on peak load increases; the effects of possible future developments on peak loads are studied, together with the consequences for the network. The city of Eindhoven (the Netherlands) is used as reference city, for which a scenario is developed in which the assumed future developments adversely influence the maximum peak loads on the network. In this scenario, the total electricity peak load in Eindhoven is expected to increase from 198 MVA in 2009 to 591-633 MVA in 2040. The necessary investments for facilitating the expected increased peak loads are estimated at 305-375 million Euros. Based upon these projections, it is advocated that - contrary to current Dutch policy - choices regarding sustainable transitions should be made from the viewpoint of integral energy systems, evaluating economic implications of changes to generation, grid development, and consumption. Recently applied and finished policies on energy demand reduction showed to be effective; however, additional and connecting policies on energy generation and distribution should be considered on short term. - Highlights: > Sustainable energy transitions can result in major electricity peak load increases. > Introduction of heat pumps and electrical vehicles requires network expansion. > Under worst case assumptions, peak loads in Eindhoven increase with 200% until 2040. > The necessary investment for facilitating this 2040 peak demand is Euro 305-375 million. > Future policy choices should be made from the viewpoint of the integral energy system.
Solar maximum mission panel jettison analysis remote manipulator system
Bauer, R. B.
1980-01-01
A study is presented of the development of the Remote Manipulator System (RMS) configurations for jettison of the solar panels on the Solar Maximum Mission/Multimission Satellite. A valid RMS maneuver between jettison configurations was developed. Arm and longeron loads and effector excursions due to the solar panel jettison were determined to see if they were within acceptable limits. These loads and end effector excursions were analyzed under two RMS modes, servos active in position hold submode, and in the brakes on mode.
Optimal load shedding and restoration
Xu, Ding
Load shedding is an emergency control action in power systems that can save systems from a wide-area blackout. Underfrequency load shedding, steady state load shedding, and voltage load shedding are widely used in power systems. These methods utilize either the steady state model or a simplified dynamic model to represent a power systems. In this dissertation, a general optimal load shedding method that considers both the dynamic process and load distribution is proposed. The unfavorable load shedding is then formulated as an optimization problem with the objective function of cost minimization. This objective function is subjected to system, security, and operation constraints. The entire problem becomes a question of optimization with differential and nonlinear equations as constraints. To solve this problem, discretization is used to change the differential equations into algebraic equations. The original problem is thus reformulated as an optimization problem and can be solved by a standard mathematical program. The general idea is then applied to traditional power systems, deregulated power systems, power systems with distributed generation, and load restoration. In the traditional power system, the method shows that governor action, generation dynamic, disturbance location, and economic factors can be taken into consideration. In the deregulated power system, two power market models are developed and incorporated into the load shedding scheme. In power systems with multiple distributed generations, the different cases of disturbances are analyzed and models of different distributed generation developed. The general idea is then applied. Finally, the load restoration problem is studied, and it is proposed that an optimization method be applied to it. This dissertation provides a comprehensive solution for load shedding problem in power systems. The models developed in this research can also be used to study other power system problems.
Shiva Alavi
2012-01-01
Conclusion: It appears dry heat sterilization increases stiffness of RES, BETA, CNA and HONE but autoclave sterilization did not have any effect on load-deflection characteristics of most of the β-titanium wires tested, indicating that clinicians who want to provide maximum safety for their patients can autoclave TMAL, RES and CNA before applying them.
Cacti with maximum Kirchhoff index
Wang, Wen-Rui; Pan, Xiang-Feng
2015-01-01
The concept of resistance distance was first proposed by Klein and Randi\\'c. The Kirchhoff index $Kf(G)$ of a graph $G$ is the sum of resistance distance between all pairs of vertices in $G$. A connected graph $G$ is called a cactus if each block of $G$ is either an edge or a cycle. Let $Cat(n;t)$ be the set of connected cacti possessing $n$ vertices and $t$ cycles, where $0\\leq t \\leq \\lfloor\\frac{n-1}{2}\\rfloor$. In this paper, the maximum kirchhoff index of cacti are characterized, as well...
Generic maximum likely scale selection
Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo
2007-01-01
The fundamental problem of local scale selection is addressed by means of a novel principle, which is based on maximum likelihood estimation. The principle is generally applicable to a broad variety of image models and descriptors, and provides a generic scale estimation methodology. The focus...... on second order moments of multiple measurements outputs at a fixed location. These measurements, which reflect local image structure, consist in the cases considered here of Gaussian derivatives taken at several scales and/or having different derivative orders....
Economics and Maximum Entropy Production
Lorenz, R. D.
2003-04-01
Price differentials, sales volume and profit can be seen as analogues of temperature difference, heat flow and work or entropy production in the climate system. One aspect in which economic systems exhibit more clarity than the climate is that the empirical and/or statistical mechanical tendency for systems to seek a maximum in production is very evident in economics, in that the profit motive is very clear. Noting the common link between 1/f noise, power laws and Self-Organized Criticality with Maximum Entropy Production, the power law fluctuations in security and commodity prices is not inconsistent with the analogy. There is an additional thermodynamic analogy, in that scarcity is valued. A commodity concentrated among a few traders is valued highly by the many who do not have it. The market therefore encourages via prices the spreading of those goods among a wider group, just as heat tends to diffuse, increasing entropy. I explore some empirical price-volume relationships of metals and meteorites in this context.
Chen, Larry; Gordon, Karen; Hurtig, Mark
2014-10-01
Design and validation of a magnetic resonance and computed tomography compatible device capable of applying physiologically relevant muscle forces to cadaveric knee joints with high levels of repeatability and reproducibility. Repeatability and reproducibility were assessed with two porcine stifle joints. Load was applied to joints at full extension, five and 15 degrees of flexion through two cables simulating the lines of action of the quadriceps and hamstrings muscles. Five repeatability and five reproducibility trials were performed at each flexion angle. Standard deviations (SDs) of joint angle and load were recorded. For repeatability, the maximum SDs for joint angle were 1.26° (flexion), 1.54° (ab/adduction) and 0.90° (in/external rotation). The maximum SDs for joint load were 4.60 N (anterior/posterior), 7.36 N (medial/lateral), and 42.6N (axial). For reproducibility, the maximum SDs for joint angle were 0.84° (flexion), 0.66° (ab/adduction) and 0.92° (in/external rotation). The maximum SDs for joint load were 6.40 N (anterior/posterior), 11.7 N (medial/lateral), and 39.7 N (axial). This level of repeatability and reproducibility is within intra-subject variability of measured gait kinematics. Therefore, this device is considered to be an effective tool for in vitro testing of knee soft tissue repair. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.
Risk Analysis of Breakwater Caisson Under Wave Attack Using Load Surface Approximation
Dong Hyawn KIM
2014-01-01
A new load surface based approach to the reliability analysis of caisson-type breakwater is proposed. Uncertainties of the horizontal and vertical wave loads acting on breakwater are considered by using the so-called load surfaces, which can be estimated as functions of wave height, water level, and so on. Then, the first-order reliability method (FORM) can be applied to determine the probability of failure under the wave action. In this way, the reliability analysis of breakwaters with uncertainties both in wave height and in water level is possible. Moreover, the uncertainty in wave breaking can be taken into account by considering a random variable for wave height ratio which relates the significant wave height to the maximum wave height. The proposed approach is applied numerically to the reliability analysis of caisson breakwater under wave attack that may undergo partial or full wave breaking.
Efficiency at maximum power of thermally coupled heat engines.
Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph
2012-04-01
We study the efficiency at maximum power of two coupled heat engines, using thermoelectric generators (TEGs) as engines. Assuming that the heat and electric charge fluxes in the TEGs are strongly coupled, we simulate numerically the dependence of the behavior of the global system on the electrical load resistance of each generator in order to obtain the working condition that permits maximization of the output power. It turns out that this condition is not unique. We derive a simple analytic expression giving the relation between the electrical load resistance of each generator permitting output power maximization. We then focus on the efficiency at maximum power (EMP) of the whole system to demonstrate that the Curzon-Ahlborn efficiency may not always be recovered: The EMP varies with the specific working conditions of each generator but remains in the range predicted by irreversible thermodynamics theory. We discuss our results in light of nonideal Carnot engine behavior.
Chen, Jincan; Yan, Zijun; Wu, Liqing
1996-06-01
Considering a thermoelectric generator as a heat engine cycle, the general differential equations of the temperature field inside thermoelectric elements are established by means of nonequilibrium thermodynamics. These equations are used to study the influence of heat leak, Joule's heat, and Thomson heat on the performance of the thermoelectric generator. New expressions are derived for the power output and the efficiency of the thermoelectric generator. The maximum power output is calculated and the optimal matching condition of load is determined. The maximum efficiency is discussed by a representative numerical example. The aim of this research is to provide some novel conclusions and redress some errors existing in a related investigation.
Fracture behaviour of a self-healing microcapsule-loaded epoxy system
2011-03-01
Full Text Available The effect of temperature on the fracture behaviour of a microcapsule-loaded epoxy matrix was investigated. Microencapsulated epoxy and mercaptan-derivative healing agents were incorporated into an epoxy matrix to produce a polymer composite capable of self-healing. Maximum fracture loads were measured using the double-torsion method. Thermal aging at 55 and 110°C for 17 hours [hrs] was applied to heal the pre-cracked samples. The addition of microcapsules appeared to increase significantly the load carrying capacity of the epoxy after healing. Once healed, the composites achieved as much as 93–171% of its virgin maximum fracture load at 18, 55 and 110°C. The fracture behavior of the microcapsule- loaded epoxy matrix was influenced by the healing temperature. The high self-healing efficiency may be attributed to the result of the subsurface micro-crack pinning or deviation, and to a stronger microencapsulated epoxy and mercaptanderivative binder than that of the bulk epoxy. The results show that the healing temperature has a significant effect on recovery of load transferring capability after fracture.
A Study on Assessment Method of Traffic Load Effect of Bridge in Service
Ling, Pan; Dajian, Han
2010-05-01
Because of overloading usually occur in highway in China today, it is found that the traffic load and the load effects given by Specification for Inspection and Evaluation of Load-bearing Capacity of Highway Bridge[1] cannot be adequately estimated. Especially, the extreme values in a service period can not be predicted. In this paper, a model is first developed for a better estimation of the actual traffic flow, as well as the service load effect level of a bridge. Based on a five-day collection data of the vehicle samples passing through the exit of Guangyuan to Shahe of the North-Ring Highway in Guangzhou, The Qiaole Bridge of the highway is taken as an example to illustrate the assessment model. Then, a threshold model is applied to estimate the tail distribution of the maximum load effect of a fleet. And threshold point process is used to infer the maximum value distribution for prediction of the load effect level of the bridge in a future time period. Finally, a 0.95 quantile is obtained to compare with the result given by specification[1]. The results show that the assessment method proposed in this paper is valid and feasible.
Objects of maximum electromagnetic chirality
Fernandez-Corbaton, Ivan
2015-01-01
We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. The upper bound is attained if and only if the object is transparent for fields of one handedness (helicity). Additionally, electromagnetic duality symmetry, i.e. helicity preservation upon scattering, turns out to be a necessary condition for reciprocal scatterers to attain the upper bound. We use these results to provide requirements for the design of such extremal scatterers. The requirements can be formulated as constraints on the polarizability tensors for dipolar scatterers or as material constitutive relations. We also outline two applications for objects of maximum electromagnetic chirality: A twofold resonantly enhanced and background free circular dichroism measurement setup, and angle independent helicity filtering glasses.
Maximum mutual information regularized classification
Wang, Jim Jing-Yan
2014-09-07
In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.
Experimental study on prediction model for maximum rebound ratio
LEI Wei-dong; TENG Jun; A.HEFNY; ZHAO Jian; GUAN Jiong
2007-01-01
The proposed prediction model for estimating the maximum rebound ratio was applied to a field explosion test, Mandai test in Singapore.The estimated possible maximum Deak particle velocities(PPVs)were compared with the field records.Three of the four available field-recorded PPVs lie exactly below the estimated possible maximum values as expected.while the fourth available field-recorded PPV lies close to and a bit higher than the estimated maximum possible PPV The comparison results show that the predicted PPVs from the proposed prediction model for the maximum rebound ratio match the field.recorded PPVs better than those from two empirical formulae.The very good agreement between the estimated and field-recorded values validates the proposed prediction model for estimating PPV in a rock mass with a set of ipints due to application of a two dimensional compressional wave at the boundary of a tunnel or a borehole.
Fatigue crack growth from narrow-band Gaussian spectrum loading in 6063 aluminum alloy
Veers, P.S.; Van Den Avyle, J.A.
1990-01-01
Constant amplitude and narrow-band Gaussian loadings are applied to extruded 6063 aluminum crack-growth specimens in an effort to characterize the effective stress intensity levels during random loading. Crack-growth rates are determined for constant amplitude loadings at stress ratios (R) of 0.09, 0.3 and 0.5, and for a variable amplitude loading simulated to match a narrow-band Gaussian spectrum. Crack-opening stress levels measured by the compliance method during the constant amplitude loading are found to differ substantially for -T5 and -T6 heat treatments due to a change from intergranular to transgranular crack growth. Crack-opening load ratios correlate well with the maximum applied stress intensity factor, K{sub max}, for the -T5 material. The K{sub max} dependence leads to an effective halving of the crack-growth exponent. Calculated variable amplitude lives are much shorter when this correlation is taken into account (an acceleration effect) and show a greater difference between loading blocks condensed by racetrack filtering at threshold levels of two and four standard deviations, similar to what was observed in the tests. Crack-opening-load measurements in one specimen with the narrow-band Gaussian (variable amplitude) loading failed to detect any closure. A substantial difference in the closure behavior of nominally identical R = .3 tests indicates that closure may occur irregularly in the extruded aluminum. Calculated crack-growth lives, assuming no closure in the variable amplitude tests, are much shorter than the test results. Including closure in the variable amplitude loadings greatly improves the predictions. 14 refs., 16 figs.
Invulnerability of power grids based on maximum flow theory
Fan, Wenli; Huang, Shaowei; Mei, Shengwei
2016-11-01
The invulnerability analysis against cascades is of great significance in evaluating the reliability of power systems. In this paper, we propose a novel cascading failure model based on the maximum flow theory to analyze the invulnerability of power grids. In the model, node initial loads are built on the feasible flows of nodes with a tunable parameter γ used to control the initial node load distribution. The simulation results show that both the invulnerability against cascades and the tolerance parameter threshold αT are affected by node load distribution greatly. As γ grows, the invulnerability shows the distinct change rules under different attack strategies and different tolerance parameters α respectively. These results are useful in power grid planning and cascading failure prevention.
Maximum Power Point Tracking of Photovoltaic System Using Intelligent Controller
Swathy C.S
2013-04-01
Full Text Available Photovoltaic systems normally use a maximum power point tracking (MPPT technique to continuously give forth the highest probable power to the load when the temperature and solar irradiationchanges occur. This subdues the problem of mismatch between the given load and the solar array. The energy conservation principle is used to obtain small signal model and transfer function. A simulationwork handling with MPPT controller, a DC/DC boost converter feeding a load is achieved. PI controller and fuzzy logic controllers were used as the MPPT controller, which controls the dc/dc converter. Simulations and experimental results showed excellent performance and were used for comparing PI controller and fuzzy logic controller.
贾剑; 王丽敏
2014-01-01
母杜柴登煤矿二期工程施工初期，在不具备后配套连续运输的条件下，布置简易储矸转载系统，解决了悬臂式掘进机快速掘进与电机车牵引矿车间断运输不匹配的技术难题，提高了巷道施工进度，取得了月进尺达180～235 m的好成绩。简易储矸转载系统除可与悬臂式掘进机配套使用外，还可与连采机、掘锚机等机掘设备配套使用，具有推广应用价值。%At an initial construction period of the second phase engineering of Mudu Chaideng Coal Mine ,under a condition with no back supporting continuous transportation ,a simple coal refuse stor‐age and stage loading system was arranged to solve a mismatching technical problem between the rapid driving of the mine boom type roadheader and the discontinuous transportation of the mine cars hauled by the mine electric locomotive. The mine gateway construction schedule was improved and a month driving rate reached an excellent achievement of 180~235m. T he simple coal refuse storage and stage loading system could not only be matched with boom type roadheader ,but also could be matched with the continuous miner ,driving an bolting machine and other mechanized equipment. The simple coal re‐fuse storage and stage loading system could have the promoted and application value.
Newhouse, Vernon L
1975-01-01
Applied Superconductivity, Volume II, is part of a two-volume series on applied superconductivity. The first volume dealt with electronic applications and radiation detection, and contains a chapter on liquid helium refrigeration. The present volume discusses magnets, electromechanical applications, accelerators, and microwave and rf devices. The book opens with a chapter on high-field superconducting magnets, covering applications and magnet design. Subsequent chapters discuss superconductive machinery such as superconductive bearings and motors; rf superconducting devices; and future prospec
Maximum entropy production and the fluctuation theorem
Dewar, R C [Unite EPHYSE, INRA Centre de Bordeaux-Aquitaine, BP 81, 33883 Villenave d' Ornon Cedex (France)
2005-05-27
Recently the author used an information theoretical formulation of non-equilibrium statistical mechanics (MaxEnt) to derive the fluctuation theorem (FT) concerning the probability of second law violating phase-space paths. A less rigorous argument leading to the variational principle of maximum entropy production (MEP) was also given. Here a more rigorous and general mathematical derivation of MEP from MaxEnt is presented, and the relationship between MEP and the FT is thereby clarified. Specifically, it is shown that the FT allows a general orthogonality property of maximum information entropy to be extended to entropy production itself, from which MEP then follows. The new derivation highlights MEP and the FT as generic properties of MaxEnt probability distributions involving anti-symmetric constraints, independently of any physical interpretation. Physically, MEP applies to the entropy production of those macroscopic fluxes that are free to vary under the imposed constraints, and corresponds to selection of the most probable macroscopic flux configuration. In special cases MaxEnt also leads to various upper bound transport principles. The relationship between MaxEnt and previous theories of irreversible processes due to Onsager, Prigogine and Ziegler is also clarified in the light of these results. (letter to the editor)
Maximum Profit Configurations of Commercial Engines
Yiran Chen
2011-06-01
Full Text Available An investigation of commercial engines with finite capacity low- and high-price economic subsystems and a generalized commodity transfer law [n ∝ Δ (P m] in commodity flow processes, in which effects of the price elasticities of supply and demand are introduced, is presented in this paper. Optimal cycle configurations of commercial engines for maximum profit are obtained by applying optimal control theory. In some special cases, the eventual state—market equilibrium—is solely determined by the initial conditions and the inherent characteristics of two subsystems; while the different ways of transfer affect the model in respects of the specific forms of the paths of prices and the instantaneous commodity flow, i.e., the optimal configuration.
Maximum stellar iron core mass
F W Giacobbe
2003-03-01
An analytical method of estimating the mass of a stellar iron core, just prior to core collapse, is described in this paper. The method employed depends, in part, upon an estimate of the true relativistic mass increase experienced by electrons within a highly compressed iron core, just prior to core collapse, and is signiﬁcantly different from a more typical Chandrasekhar mass limit approach. This technique produced a maximum stellar iron core mass value of 2.69 × 1030 kg (1.35 solar masses). This mass value is very near to the typical mass values found for neutron stars in a recent survey of actual neutron star masses. Although slightly lower and higher neutron star masses may also be found, lower mass neutron stars are believed to be formed as a result of enhanced iron core compression due to the weight of non-ferrous matter overlying the iron cores within large stars. And, higher mass neutron stars are likely to be formed as a result of fallback or accretion of additional matter after an initial collapse event involving an iron core having a mass no greater than 2.69 × 1030 kg.
Maximum Matchings via Glauber Dynamics
Jindal, Anant; Pal, Manjish
2011-01-01
In this paper we study the classic problem of computing a maximum cardinality matching in general graphs $G = (V, E)$. The best known algorithm for this problem till date runs in $O(m \\sqrt{n})$ time due to Micali and Vazirani \\cite{MV80}. Even for general bipartite graphs this is the best known running time (the algorithm of Karp and Hopcroft \\cite{HK73} also achieves this bound). For regular bipartite graphs one can achieve an $O(m)$ time algorithm which, following a series of papers, has been recently improved to $O(n \\log n)$ by Goel, Kapralov and Khanna (STOC 2010) \\cite{GKK10}. In this paper we present a randomized algorithm based on the Markov Chain Monte Carlo paradigm which runs in $O(m \\log^2 n)$ time, thereby obtaining a significant improvement over \\cite{MV80}. We use a Markov chain similar to the \\emph{hard-core model} for Glauber Dynamics with \\emph{fugacity} parameter $\\lambda$, which is used to sample independent sets in a graph from the Gibbs Distribution \\cite{V99}, to design a faster algori...
2011-01-10
...: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure Using Record Evidence, and... facilities of their responsibilities, under Federal integrity management (IM) regulations, to perform... system, especially when calculating Maximum Allowable Operating Pressure (MAOP) or Maximum Operating...
Kinoshita, Kanji; Murayama, Kouichi; Ogata, Hiroyuki [and others
1997-04-01
The fracture behavior for Japanese carbon steel pipe STS410 was examined under dynamic monotonic and cyclic loading through a research program of International Piping Integrity Research Group (EPIRG-2), in order to evaluate the strength of pipe during the seismic event The tensile test and the fracture toughness test were conducted for base metal and TIG weld metal. Three base metal pipe specimens, 1,500mm in length and 6-inch diameter sch.120, were employed for a quasi-static monotonic, a dynamic monotonic and a dynamic cyclic loading pipe fracture tests. One weld joint pipe specimen was also employed for a dynamic cyclic loading test In the dynamic cyclic loading test, the displacement was controlled as applying the fully reversed load (R=-1). The pipe specimens with a circumferential through-wall crack were subjected four point bending load at 300C in air. Japanese STS410 carbon steel pipe material was found to have high toughness under dynamic loading condition through the CT fracture toughness test. As the results of pipe fracture tests, the maximum moment to pipe fracture under dynamic monotonic and cyclic loading condition, could be estimated by plastic collapse criterion and the effect of dynamic monotonic loading and cyclic loading was a little on the maximum moment to pipe fracture of the STS410 carbon steel pipe. The STS410 carbon steel pipe seemed to be less sensitive to dynamic and cyclic loading effects than the A106Gr.B carbon steel pipe evaluated in IPIRG-1 program.
Impedance matching between ventricle and load.
Piene, H
1984-01-01
Impedance matching in the cardiovascular system is discussed in light of two models of ventricle and load: a Thevenin equivalent consisting of a hydromotive pressure source and an internal, source resistance and compliance in parallel; and a time-varying compliance filled from a constant pressure source and ejecting into a load of three components, a central resistor, a compliance, and a peripheral resistance. According to the Thevenin analog, the energy source and the load are matched when the load resistance is T/t times the internal source resistance (T is total cycle length, t is systolic time interval). Both from this model and from the variable compliance model it appears that optimum matching between source and load depends on the compliance of the Windkessel, as low compliance shifts the matching load resistance to a low value. Animal experiments (isolated cat hearts) indicated that both left and right ventricles at normal loads work close to their maxima of output hydraulic power, and, according to experiments in the right ventricle, maximum power output is related to load resistance and compliance as predicted by the above models. From an experimentally determined relationship among instantaneous ventricular pressure and volume (right ventricle of isolated cat hearts), an optimum load impedance was calculated on the basis of the assumption that the ratio between stroke work and static, potential energy developed in the ventricular cavity is maximum. The optimum load impedance found by this procedure closely resembles the normal input impedance of the cat lung vessel bed.
Logan, J David
2013-01-01
Praise for the Third Edition"Future mathematicians, scientists, and engineers should find the book to be an excellent introductory text for coursework or self-study as well as worth its shelf space for reference." -MAA Reviews Applied Mathematics, Fourth Edition is a thoroughly updated and revised edition on the applications of modeling and analyzing natural, social, and technological processes. The book covers a wide range of key topics in mathematical methods and modeling and highlights the connections between mathematics and the applied and nat
Konstandinos G. Raptis
2012-01-01
Full Text Available Purpose of this study is the consideration of loading and contact problems encountered at rotating machine elements and especially at toothed gears. The later are some of the most commonly used mechanical components for rotary motion and power transmission. This fact proves the necessity for improved reliability and enhanced service life, which require precise and clear knowledge of the stress field at gear tooth. This study investigates the maximum allowable stresses occurring during spur gear tooth meshing computed using Niemannâs formulas at Highest Point of Single Tooth Contact (HPSTC. Gear material, module, power rating and number of teeth are considered as variable parameters. Furthermore, the maximum allowable stresses for maximum power transmission conditions are considered keeping the other parameters constant. After the application of Niemannâs formulas to both loading cases, the derived results are compared to the respective estimations of Finite Element Method (FEM using ANSYS software. Comparison of the results derived from Niemannâs formulas and FEM show that deviations between the two methods are kept at low level for both loading cases independently of the applied power (either random or maximum and the respective tangential load.
The Sherpa Maximum Likelihood Estimator
Nguyen, D.; Doe, S.; Evans, I.; Hain, R.; Primini, F.
2011-07-01
A primary goal for the second release of the Chandra Source Catalog (CSC) is to include X-ray sources with as few as 5 photon counts detected in stacked observations of the same field, while maintaining acceptable detection efficiency and false source rates. Aggressive source detection methods will result in detection of many false positive source candidates. Candidate detections will then be sent to a new tool, the Maximum Likelihood Estimator (MLE), to evaluate the likelihood that a detection is a real source. MLE uses the Sherpa modeling and fitting engine to fit a model of a background and source to multiple overlapping candidate source regions. A background model is calculated by simultaneously fitting the observed photon flux in multiple background regions. This model is used to determine the quality of the fit statistic for a background-only hypothesis in the potential source region. The statistic for a background-plus-source hypothesis is calculated by adding a Gaussian source model convolved with the appropriate Chandra point spread function (PSF) and simultaneously fitting the observed photon flux in each observation in the stack. Since a candidate source may be located anywhere in the field of view of each stacked observation, a different PSF must be used for each observation because of the strong spatial dependence of the Chandra PSF. The likelihood of a valid source being detected is a function of the two statistics (for background alone, and for background-plus-source). The MLE tool is an extensible Python module with potential for use by the general Chandra user.
程启明; 程尹曼; 王映斐; 胡晓青
2011-01-01
The load object of ball mill in thermal power plant has the complex traits with large time-delay, slow time-varying, strongly nonlinear, etc. It is difficult to obtain satisfactory control performance using conventional control methods. In this paper, the active disturbance rejection control method based on gray prediction model was introduced to load control. In this control system, gray prediction model and disturbance rejection were combined, gray prediction model was added to conventional disturbance rejection control, and the parameters of control system were optimized by adaptive genetic algorithm. The simulation results show that the control method has fast response, small overshoot, good robustness, strong anti - interference ability, it can effectively solve the large time-delay, nonlinear and adaptive problems.%火电厂钢球磨煤机的负荷对象具有大滞后、慢时变、强非线性等复杂特性,采用常规控制方法难以获得满意的控制效果,文章提出了基于灰色预测模型的自抗扰负荷控制方法,它把灰色预测模型与自抗扰控制结合起来,在常规的自抗扰控制中加入灰色预测模型的控制方法,并且控制系统的参数采用自适应遗传算法进行优化；仿真结果表明这种控制方法系统响应快、超调小、鲁棒性好、抗干扰能力强,可以有效解决大滞后、非线性及适应性等问题.
STUDY ON MAXIMUM SPECIFIC SLUDGE ACIVITY OF DIFFERENT ANAEROBIC GRANULAR SLUDGE BY BATCH TESTS
无
2001-01-01
The maximum specific sludge activity of granular sludge from large-scale UASB, IC and Biobed anaerobic reactors were investigated by batch tests. The limitation factors related to maximum specific sludge activity (diffusion, substrate sort, substrate concentration and granular size) were studied. The general principle and procedure for the precise measurement of maximum specific sludge activity were suggested. The potential capacity of loading rate of the IC and Biobed anaerobic reactors were analyzed and compared by use of the batch tests results.
Load Deflection Characteristics of Nickel Titanium Initial Archwires
Hossein Aghili
2016-05-01
Full Text Available Objectives: The aim of this study was to assess and compare the characteristics of commonly used initial archwires by their load deflection graphs.Materials and Methods: This study tested three wire designs namely copper nickel titanium (CNT, nickel titanium (NiTi, and multi-strand NiTi (MSNT archwires engaged in passive self-ligating (PSL brackets, active self-ligating (ASL brackets or conventional brackets. To evaluate the mechanical characteristics of the specimens, a three-point bending test was performed. The testing machine vertically applied force on the midpoint of the wire between the central incisor and canine teeth to obtain 2 and 4mm of deflection. The force level at maximum deflection and characteristics of plateau (the average plateau load and the plateau length were recorded. Two-way ANOVA and Tukey’s test were used at P <0.05 level of significance.Results: Force level at maximum deflection and plateau length were significantly affected by the amount of deflection. The type of archwires and brackets had significant effects on force level at maximum deflection, and plateau length. However, the bracket type had no significant effect on the average plateau force.Conclusion: With any type of brackets in deflections of 2 and 4mm, MSNT wire exerted the lowest while NiTi wire exerted the highest force level at maximum deflection and plateau phase. The force level at maximum deflection and the plateau length increased with raising the amount of primary deflection; however the average plateau force did not change significantly.
Manoharan, Asha; Dreisbach, Joseph H.
1988-01-01
Describes some examples of chemical and industrial applications of enzymes. Includes a background, a discussion of structure and reactivity, enzymes as therapeutic agents, enzyme replacement, enzymes used in diagnosis, industrial applications of enzymes, and immobilizing enzymes. Concludes that applied enzymology is an important factor in…
Multilayered elastic analysis formulation for surface moment loading
Maina, JW
2006-01-01
Full Text Available to the action of non-uniform circular loading is presented in this paper. Results show that maximum compressive stress at the pavement surface due to triangular load was greater by 20% and 70% than results from uniformly distributed vertical load and horizontal...
Assessment of the Uniqueness of Wind Tunnel Strain-Gage Balance Load Predictions
Ulbrich, N.
2016-01-01
A new test was developed to assess the uniqueness of wind tunnel strain-gage balance load predictions that are obtained from regression models of calibration data. The test helps balance users to gain confidence in load predictions of non-traditional balance designs. It also makes it possible to better evaluate load predictions of traditional balances that are not used as originally intended. The test works for both the Iterative and Non-Iterative Methods that are used in the aerospace testing community for the prediction of balance loads. It is based on the hypothesis that the total number of independently applied balance load components must always match the total number of independently measured bridge outputs or bridge output combinations. This hypothesis is supported by a control volume analysis of the inputs and outputs of a strain-gage balance. It is concluded from the control volume analysis that the loads and bridge outputs of a balance calibration data set must separately be tested for linear independence because it cannot always be guaranteed that a linearly independent load component set will result in linearly independent bridge output measurements. Simple linear math models for the loads and bridge outputs in combination with the variance inflation factor are used to test for linear independence. A highly unique and reversible mapping between the applied load component set and the measured bridge output set is guaranteed to exist if the maximum variance inflation factor of both sets is less than the literature recommended threshold of five. Data from the calibration of a six{component force balance is used to illustrate the application of the new test to real-world data.
Schiehlen, Werner
2014-01-01
Applied Dynamics is an important branch of engineering mechanics widely applied to mechanical and automotive engineering, aerospace and biomechanics as well as control engineering and mechatronics. The computational methods presented are based on common fundamentals. For this purpose analytical mechanics turns out to be very useful where D’Alembert’s principle in the Lagrangian formulation proves to be most efficient. The method of multibody systems, finite element systems and continuous systems are treated consistently. Thus, students get a much better understanding of dynamical phenomena, and engineers in design and development departments using computer codes may check the results more easily by choosing models of different complexity for vibration and stress analysis.
2009-01-01
A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...
Individual Module Maximum Power Point Tracking for a Thermoelectric Generator Systems
Vadstrup, Casper; Chen, Min; Schaltz, Erik
Thermo Electric Generator (TEG) modules are often connected in a series and/or parallel system in order to match the TEG system voltage with the load voltage. However, in order to be able to control the power production of the TEG system a DC/DC converter is inserted between the TEG system...... and the load. The DC/DC converter is under the control of a Maximum Power Point Tracker (MPPT) which insures that the TEG system produces the maximum possible power to the load. However, if the conditions, e.g. temperature, health, etc., of the TEG modules are different each TEG module will not produce its...... maximum power. The result of the system MPPT is therefore the best compromise of all the TEG modules in the system. On the other hand, if each TEG module is controlled individual, each TEG module can be operated in its maximum power point and the TEG system output power will therefore be higher...
戴邵武; 李双明; 杨智勇; 张文广
2012-01-01
Lower extremity exoskeleton need to achieve the function of power under condition of the changing load and accurately track the trajectory of the body's expectations. Based on the system's dynamic equation, the Robust Adaptive PD control method was proposed in this paper. The disturbance outside system, joint friction and noise were taken as the upper bound known disturbance item. In the designing controller, middle variable was introduced to calculate the regression matrix, which the joint variables are the parameters of, and the constant unknown vector, which describes the mass characters of the exoskeleton. The adaptive law was designed with the regression matrix and middle variable. Simulation results show that, the exoskeleton can exactly track the desired trajectory to improve the robustness of the system and to achieve variable load control.%下肢负荷外骨骼需要在变负载情况下实现助力的功能,外骨骼应能准确地跟踪人体的期望运动轨迹.为此,基于系统的动力学模型,提出了鲁棒自适应PD控制方法.该方法将系统外界的干扰、关节摩擦和噪声统一为上确界已知的干扰项,在控制器设计时引入中间变量,计算出以关节变量为参数的回归矩阵和一个描述外骨骼质量特性的未知定常参数向量,利用回归矩阵和引入的中间变量设计自适应律.仿真结果表明,外骨骼能够准确跟踪上期望的运动轨迹,系统的鲁棒性得到改善,实现了系统变负载控制的目的.
Functional stability limits while holding loads in various positions.
Holbein, M A; Redfern, M S
1997-05-01
Stability of the body during manual material handling is an important issue in the prevention of falls and over-exertion injuries. This research investigated stability limits while standing and holding loads in different positions relative to the body. Theoretically, the stability region is the full base of support defined by the perimeter of the foot contact area. However, the functional stability region may be smaller. The purpose of this study was to locate functional stability limits with respect to the base of support. Fifteen male subjects leaned as far as possible in four directions in the sagittal and frontal planes. Their center of gravity location at these extremes determined the stability limit. The results showed that functional stability limits reached only about 60% of the distance to the maximum base of support limits under the conditions of this study. The sway angles reached at the stability limits averaged 9.2 degrees anteroposteriorly and 15.3 degrees laterally. External load positions which lowered the center of gravity of the body-and-load system extended those stability limits. This study provides a postural stability perspective of load-holding which may be applied in establishing safe lifting and reach limits.
Individual Module Maximum Power Point Tracking for Thermoelectric Generator Systems
Vadstrup, Casper; Schaltz, Erik; Chen, Min
2013-07-01
In a thermoelectric generator (TEG) system the DC/DC converter is under the control of a maximum power point tracker which ensures that the TEG system outputs the maximum possible power to the load. However, if the conditions, e.g., temperature, health, etc., of the TEG modules are different, each TEG module will not produce its maximum power. If each TEG module is controlled individually, each TEG module can be operated at its maximum power point and the TEG system output power will therefore be higher. In this work a power converter based on noninverting buck-boost converters capable of handling four TEG modules is presented. It is shown that, when each module in the TEG system is operated under individual maximum power point tracking, the system output power for this specific application can be increased by up to 8.4% relative to the situation when the modules are connected in series and 16.7% relative to the situation when the modules are connected in parallel.
Improved Neural Networks with Random Weights for Short-Term Load Forecasting.
Kun Lang
Full Text Available An effective forecasting model for short-term load plays a significant role in promoting the management efficiency of an electric power system. This paper proposes a new forecasting model based on the improved neural networks with random weights (INNRW. The key is to introduce a weighting technique to the inputs of the model and use a novel neural network to forecast the daily maximum load. Eight factors are selected as the inputs. A mutual information weighting algorithm is then used to allocate different weights to the inputs. The neural networks with random weights and kernels (KNNRW is applied to approximate the nonlinear function between the selected inputs and the daily maximum load due to the fast learning speed and good generalization performance. In the application of the daily load in Dalian, the result of the proposed INNRW is compared with several previously developed forecasting models. The simulation experiment shows that the proposed model performs the best overall in short-term load forecasting.
Improved Neural Networks with Random Weights for Short-Term Load Forecasting.
Lang, Kun; Zhang, Mingyuan; Yuan, Yongbo
2015-01-01
An effective forecasting model for short-term load plays a significant role in promoting the management efficiency of an electric power system. This paper proposes a new forecasting model based on the improved neural networks with random weights (INNRW). The key is to introduce a weighting technique to the inputs of the model and use a novel neural network to forecast the daily maximum load. Eight factors are selected as the inputs. A mutual information weighting algorithm is then used to allocate different weights to the inputs. The neural networks with random weights and kernels (KNNRW) is applied to approximate the nonlinear function between the selected inputs and the daily maximum load due to the fast learning speed and good generalization performance. In the application of the daily load in Dalian, the result of the proposed INNRW is compared with several previously developed forecasting models. The simulation experiment shows that the proposed model performs the best overall in short-term load forecasting.
Damasceno, Leonardo H S; Rodrigues, José A D; Ratusznei, Suzana M; Zaiat, Marcelo; Foresti, Eugênio
2007-12-01
An investigation was carried out on the performance of an anaerobic sequencing batch biofilm reactor (ASBBR) treating diluted cheese whey when submitted to different feed strategies and volumetric organic loads (VOL). Polyurethane foam cubes were used as support for biomass immobilization and stirring was provided by helix impellers. The reactor with a working volume of 3 L treated 2 L of wastewater in 8-h cycles at 500 rpm and 30 degrees C. The organic loads applied were 2, 4, 8 and 12 g COD L(-1) d(-1), obtained by increasing the feed concentration. Alkalinity was supplemented at a ratio of 50% NaHCO(3)/COD. For each organic load applied three feed strategies were tested: (a) batch operation with 8-h cycle; (b) 2-h fed-batch operation followed by 6-h batch; and (c) 4-h fed-batch followed by 4-h batch. The 2-h fed-batch operation followed by 6-h batch presented the best results for the organic loads of 2 and 4 g COD L(-1) d(-1), whereas the 4-h fed-batch operation followed by 4-h batch presented results slightly inferior for the same organic loads and the best results at organic loads of 8 and 12 g COD L(-1) d(-1). The concentration of total volatile acids varied with fill time. For the higher fill times maximum concentrations were obtained at the end of the cycle. Moreover, no significant difference was detected in the maximum concentration of total volatile acids for any of the investigated conditions. However, the maximum values of propionic acid tended to decrease with increasing fill time considering the same organic load. Microbiological analyses revealed the presence of Methanosaeta-like structures and methanogenic hydrogenotrophic-like fluorescent bacilli. No Methanosarcina-like structures were observed in the samples.
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 eccentric torque increased significantly after accentuated eccentric load training only (10 ± 9%, p eccentric load (10 ± 9%, p eccentric load group was significantly greater (p eccentric load group only (28%, p eccentric load training led
Beat eMeier
2015-06-01
Full Text Available In prospective memory tasks different kinds of load can occur. Adding a prospective memory task can impose a load on ongoing task performance. Adding ongoing task load can affect prospective memory performance. The existence of multiple target events increases prospective load and adding complexity to the to-be-remembered action increases retrospective load. In two experiments, we systematically examined the effects of these different types of load on prospective memory performance. Results showed an effect of prospective load on costs in the ongoing task for categorical targets (Experiment 2, but not for specific targets (Experiment 1. Retrospective load and ongoing task load both affected remembering the retrospective component of the prospective memory task. We suggest that prospective load can enhance costs in the ongoing task due to additional monitoring requirements. Retrospective load and ongoing task load seem to impact the division of resources between the ongoing task and retrieval of the retrospective component, which may affect disengagement from the ongoing task. In general, the results demonstrate that the different types of load affect prospective memory differentially.
Jin, Xinzhe; Nakamoto, Tatsushi; Ogitsu, Toru; Yamamoto, Akira; Sugano, Michinaka [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Harjo, Stefanus; Aizawa, Kazuya; Abe, Jun; Gong, Wu; Iwahashi, Takaaki [Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Hemmi, Tsutomu [Japan Atomic Energy Agency, Naka-shi, Ibaraki 311-0193 (Japan); Umeno, Takahiro [Taiyo Nippon Sanso Corporation, Tsukuba, Ibaraki 306-2611 (Japan)
2013-06-15
To prepare for projects such as the Large Hadron Collider upgrade, International Thermonuclear Experimental Reactor and Demonstration reactor, it is important to form a clear understanding of stress-strain properties of the materials that make up superconducting magnets. Thus, we have been studying the mechanical properties of superconducting wires using neutron diffraction measurements. To simulate operational conditions such as temperature, stress, and strain, we developed a cryogenic load frame for stress-strain measurements of materials using a neutron diffractometer at Japan Proton Accelerator Research Complex (J-PARC) Takumi beam line. The maximum load that can be applied to a sample using an external driving machine is 50 kN. Using a Gifford-MacMahon cryocooler, samples can be measured down to temperatures below 10 K when loaded. In the present paper, we describe the details of the cryogenic load frame with its test results by using type-304 stainless steel wire.
Jin, Xinzhe; Nakamoto, Tatsushi; Harjo, Stefanus; Hemmi, Tsutomu; Umeno, Takahiro; Ogitsu, Toru; Yamamoto, Akira; Sugano, Michinaka; Aizawa, Kazuya; Abe, Jun; Gong, Wu; Iwahashi, Takaaki
2013-06-01
To prepare for projects such as the Large Hadron Collider upgrade, International Thermonuclear Experimental Reactor and Demonstration reactor, it is important to form a clear understanding of stress-strain properties of the materials that make up superconducting magnets. Thus, we have been studying the mechanical properties of superconducting wires using neutron diffraction measurements. To simulate operational conditions such as temperature, stress, and strain, we developed a cryogenic load frame for stress-strain measurements of materials using a neutron diffractometer at Japan Proton Accelerator Research Complex (J-PARC) Takumi beam line. The maximum load that can be applied to a sample using an external driving machine is 50 kN. Using a Gifford-MacMahon cryocooler, samples can be measured down to temperatures below 10 K when loaded. In the present paper, we describe the details of the cryogenic load frame with its test results by using type-304 stainless steel wire.
Holm, L; Reitelseder, S; Pedersen, T G;
2008-01-01
individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic.......05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy......Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same...
Holm, Lars; Reitelseder, Søren; Pedersen, T.G.
2008-01-01
individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic.......05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy......Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same...
Sivarao Subramonian
2016-08-01
Full Text Available It is evident that sugarcane/bagasse is a highly potential natural composite fiber. In this study, the correlation of composition fiber amount to the mechanical strength was presented. Bagasse was treated with alkali and then reinforced in polypropylene by means of hot pressing. Fiber loading was set to be varied from 10 to 20 wt%. Composite samples were subjected to tensile, hardness, and flexural characterization. Composites with 30 wt% of fiber loading registered maximum tensile strength while with 10 wt% fiber loading registered the minimum. Hardness increases with the amount of fiber. Flexural strength and flexural modulus were found to be greater than original polypropylene. Scanning electron microscopy examination revealed the mechanisms of the strength gain in morphological point of view. The findings give manufactures and engineers a sound basis decision whether to apply the use of this composite for weight reduction especially in automotive applications or not.
Innovative Bed Load Measurement System for Large Alpine Gravel-Bed Rivers
Seitz, H.; Habersack, H. M.
2009-04-01
The aim of the work is to figure out the bed load transport processes using direct and surrogate measurement methods for the free flowing reach of the Drau River and its most important tributary Isel River, both large Alpine gravel-bed rivers, situated in the south western part of Austria. There are some techniques for bed load measurements in natural streams; we used collecting moving particles and indirectly determining transport intensity at the study sites. Former measurements in the study reach were performed also using mobile bed load samplers and fixed bed load samplers. Individually they all are adequate bed load measurement instruments - used in combination they are complementing one another, whereas each applied separately leads to specific deficits. The investigation payed special attention on results out of the geophone installations, whereas steel plate vibrations (the plates are mounted on top of concrete structures even with the river bed surface) caused by bed load particles with a diameter larger than about 20 mm are inducing a signal into the geophones. The signal above a defined threshold voltage than is recorded in a computer system as the sum of impacts during one minute intervals. The spatio-temporal distribution of the transported bed load material, its amount and the transport processes itself could be figured out for the first time out of continuous data collection since 2006 for large alpine gravel-bed rivers. Before building up the gauging stations there were no continuous recordings of bed load transport processes in large alpine rivers over their entire cross section, hence the investigation promises a better process understanding and the possibility to determine bed load transport rates and a rough approximation of the grain size distributions of the transported bed load material under different flow conditions. A relation between detected geophone records, the flow discharge and direct bed load sampling methods (Large Helley Smith
Receiver function estimated by maximum entropy deconvolution
吴庆举; 田小波; 张乃铃; 李卫平; 曾融生
2003-01-01
Maximum entropy deconvolution is presented to estimate receiver function, with the maximum entropy as the rule to determine auto-correlation and cross-correlation functions. The Toeplitz equation and Levinson algorithm are used to calculate the iterative formula of error-predicting filter, and receiver function is then estimated. During extrapolation, reflective coefficient is always less than 1, which keeps maximum entropy deconvolution stable. The maximum entropy of the data outside window increases the resolution of receiver function. Both synthetic and real seismograms show that maximum entropy deconvolution is an effective method to measure receiver function in time-domain.
Maximum Power from a Solar Panel
Michael Miller
2010-01-01
Full Text Available Solar energy has become a promising alternative to conventional fossil fuel sources. Solar panels are used to collect solar radiation and convert it into electricity. One of the techniques used to maximize the effectiveness of this energy alternative is to maximize the power output of the solar collector. In this project the maximum power is calculated by determining the voltage and the current of maximum power. These quantities are determined by finding the maximum value for the equation for power using differentiation. After the maximum values are found for each time of day, each individual quantity, voltage of maximum power, current of maximum power, and maximum power is plotted as a function of the time of day.
Maximum entropy production and plant optimization theories.
Dewar, Roderick C
2010-05-12
Plant ecologists have proposed a variety of optimization theories to explain the adaptive behaviour and evolution of plants from the perspective of natural selection ('survival of the fittest'). Optimization theories identify some objective function--such as shoot or canopy photosynthesis, or growth rate--which is maximized with respect to one or more plant functional traits. However, the link between these objective functions and individual plant fitness is seldom quantified and there remains some uncertainty about the most appropriate choice of objective function to use. Here, plants are viewed from an alternative thermodynamic perspective, as members of a wider class of non-equilibrium systems for which maximum entropy production (MEP) has been proposed as a common theoretical principle. I show how MEP unifies different plant optimization theories that have been proposed previously on the basis of ad hoc measures of individual fitness--the different objective functions of these theories emerge as examples of entropy production on different spatio-temporal scales. The proposed statistical explanation of MEP, that states of MEP are by far the most probable ones, suggests a new and extended paradigm for biological evolution--'survival of the likeliest'--which applies from biomacromolecules to ecosystems, not just to individuals.
Maximum likelihood estimates of pairwise rearrangement distances.
Serdoz, Stuart; Egri-Nagy, Attila; Sumner, Jeremy; Holland, Barbara R; Jarvis, Peter D; Tanaka, Mark M; Francis, Andrew R
2017-06-21
Accurate estimation of evolutionary distances between taxa is important for many phylogenetic reconstruction methods. Distances can be estimated using a range of different evolutionary models, from single nucleotide polymorphisms to large-scale genome rearrangements. Corresponding corrections for genome rearrangement distances fall into 3 categories: Empirical computational studies, Bayesian/MCMC approaches, and combinatorial approaches. Here, we introduce a maximum likelihood estimator for the inversion distance between a pair of genomes, using a group-theoretic approach to modelling inversions introduced recently. This MLE functions as a corrected distance: in particular, we show that because of the way sequences of inversions interact with each other, it is quite possible for minimal distance and MLE distance to differently order the distances of two genomes from a third. The second aspect tackles the problem of accounting for the symmetries of circular arrangements. While, generally, a frame of reference is locked, and all computation made accordingly, this work incorporates the action of the dihedral group so that distance estimates are free from any a priori frame of reference. The philosophy of accounting for symmetries can be applied to any existing correction method, for which examples are offered. Copyright © 2017 Elsevier Ltd. All rights reserved.
Electrical load detection aparatus
2010-01-01
A load detection technique for a load comprising multiple frequency-dependant sub-loads comprises measuring a representation of the impedance characteristic of the load; providing stored representations of a multiplicity of impedance characteristics of the load; each one of the stored representat...
Miyaguchi, Kazuyoshi; Demura, Shinichi
2008-11-01
This study aimed to examine the relationships between muscle power output using the stretch-shortening cycle (SSC) and eccentric maximum strength under elbow flexion. Eighteen young adult males pulled up a constant light load (2 kg) by ballistic elbow flexion under the following two preliminary conditions: 1) the static relaxed muscle state (SR condition), and 2) using the SSC with countermovement (SSC condition).Muscle power was determined from the product of the pulling velocity and the load mass by a power measurement instrument that adopted the weight-loading method. We assumed the pulling velocity to be the subject's muscle power parameters as a matter of convenience, because we used a constant load. The following two parameters were selected in reference to a previous study: 1) peak velocity (m x s(-1)) (peak power) and 2) 0.1-second velocity during concentric contraction (m x s(-1)) (initial power). Eccentric maximum strength by elbow flexion was measured by a handheld dynamometer.Initial power produced in the SSC condition was significantly larger than that in the SR condition. Eccentric maximum strength showed a significant and high correlation (r = 0.70) with peak power in the SSC condition but not in the SR condition. Eccentric maximum strength showed insignificant correlations with initial power in both conditions. In conclusion, it was suggested that eccentric maximum strength is associated with peak power in the SSC condition, but the contribution of the eccentric maximum strength to the SSC potentiation (initial power) may be low.
Microcanonical origin of the maximum entropy principle for open systems.
Lee, Julian; Pressé, Steve
2012-10-01
There are two distinct approaches for deriving the canonical ensemble. The canonical ensemble either follows as a special limit of the microcanonical ensemble or alternatively follows from the maximum entropy principle. We show the equivalence of these two approaches by applying the maximum entropy formulation to a closed universe consisting of an open system plus bath. We show that the target function for deriving the canonical distribution emerges as a natural consequence of partial maximization of the entropy over the bath degrees of freedom alone. By extending this mathematical formalism to dynamical paths rather than equilibrium ensembles, the result provides an alternative justification for the principle of path entropy maximization as well.
Maximum length scale in density based topology optimization
Lazarov, Boyan Stefanov; Wang, Fengwen
2017-01-01
The focus of this work is on two new techniques for imposing maximum length scale in topology optimization. Restrictions on the maximum length scale provide designers with full control over the optimized structure and open possibilities to tailor the optimized design for broader range...... of manufacturing processes by fulfilling the associated technological constraints. One of the proposed methods is based on combination of several filters and builds on top of the classical density filtering which can be viewed as a low pass filter applied to the design parametrization. The main idea...
Efficiency of autonomous soft nanomachines at maximum power.
Seifert, Udo
2011-01-14
We consider nanosized artificial or biological machines working in steady state enforced by imposing nonequilibrium concentrations of solutes or by applying external forces, torques, or electric fields. For unicyclic and strongly coupled multicyclic machines, efficiency at maximum power is not bounded by the linear response value 1/2. For strong driving, it can even approach the thermodynamic limit 1. Quite generally, such machines fall into three different classes characterized, respectively, as "strong and efficient," "strong and inefficient," and "balanced." For weakly coupled multicyclic machines, efficiency at maximum power has lost any universality even in the linear response regime.
NONE
1993-12-31
From the title, the reader is led to expect a broad practical treatise on combustion and combustion devices. Remarkably, for a book of modest dimension, the author is able to deliver. The text is organized into 12 Chapters, broadly treating three major areas: combustion fundamentals -- introduction (Ch. 1), thermodynamics (Ch. 2), fluid mechanics (Ch. 7), and kinetics (Ch. 8); fuels -- coal, municipal solid waste, and other solid fuels (Ch. 4), liquid (Ch. 5) and gaseous (Ch. 6) fuels; and combustion devices -- fuel cells (Ch. 3), boilers (Ch. 4), Otto (Ch. 10), diesel (Ch. 11), and Wankel (Ch. 10) engines and gas turbines (Ch. 12). Although each topic could warrant a complete text on its own, the author addresses each of these major themes with reasonable thoroughness. Also, the book is well documented with a bibliography, references, a good index, and many helpful tables and appendices. In short, Applied Combustion does admirably fulfill the author`s goal for a wide engineering science introduction to the general subject of combustion.
A survey of load methodologies for shuttle orbiter payloads
Chen, J. C.; Garba, J. A.; Salama, M.; Trubert, M.
1981-01-01
Loads methods currently being used to design planetary spacecraft to be launched on the shuttle orbiter are summarized. Experiences gained from expendable launch vehicle payloads are used to develop methodologies for the space shuttle orbiter payloads. The objectives for the development of a new methodology for the shuttle payloads are to reduce the cost and schedule for the payload load analysis by decoupling the payload analysis from the launch vehicle to the maximum extent possible. Methods are described for payload member load estimation or obtaining upper bounds for dynamic loads, as well as load prediction or calculating actual transient member load time histories.
Stochastic Extreme Load Predictions for Marine Structures
Jensen, Jørgen Juncher
1999-01-01
Development of rational design criteria for marine structures requires reliable estimates for the maximum wave-induced loads the structure may encounter during its operational lifetime. The paper discusses various methods for extreme value predictions taking into account the non-linearity of the ......Development of rational design criteria for marine structures requires reliable estimates for the maximum wave-induced loads the structure may encounter during its operational lifetime. The paper discusses various methods for extreme value predictions taking into account the non...
14 CFR 23.535 - Auxiliary float loads.
2010-01-01
... midway between the keel and the chine. (e) Unsymmetrical bow loading. The resultant water load consists... be applied perpendicularly to the plane of symmetry at a point midway between the keel and the...
14 CFR 25.535 - Auxiliary float loads.
2010-01-01
... between the keel and the chine. (e) Unsymmetrical bow loading. The resultant water load consists of a... applied perpendicularly to the plane of symmetry at a point midway between the keel and the chine....
New methods for dete rmining the relative load due to physical effort of the human body
Józef Szubert
2014-04-01
Full Text Available Background: The relative physical load (% VO2max is the quotient of oxygen uptake (Vo2 during physical effort and maximum oxygen uptake (VO2max by the human body. For this purpose the stress test must be performed. The relative load shows a high correlation with minute ventilation, cardiac output, heart rate, stroke volume, increased concentrations of catecholamines in the blood, inner temperature, weight, height and human body surface area. The relative load is a criterion for the maximum workloads admissible for healthy and sick workers. Besides, the classification of effort can be more precise when based on the relative load than on the energy output. Material and Methods: Based on our own and international empirical evidence and the laws of heat transfer and fluid mechanics, a model of temperature control system has been developed, involving the elements of human cardiovascular and respiratory systems. Using this model, we have been able to develop our own methods of determining the relative load, applying only the body core temperature (TW or heart rate within one minute (HR, body mass (m, height (H, and body surface area (AD instead of VO2max. Results: The values of the relative physical load (% VO2max obtained by using our own methods do not differ significantly from those obtained by other methods and by other researchers. Conclusions: The developed methods for determining the relative physical load (% VO2max do not require the exercise test to be performed, therefore, they may be considered (after verification in an experimental study a feasible alternative to current methods. Med Pr 2014;65(2:189–195
Škarabot, Jakob; Vigotsky, Andrew D.; Brown, Amanda Fernandes; Gomes, Thiago Matassoli; Novaes, Jefferson da Silva
2017-01-01
Background Foam rollers, or other similar devices, are a method for acutely increasing range of motion, but in contrast to static stretching, do not appear to have detrimental effects on neuromuscular performance. Purpose The purpose of this study was to investigate the effects of different volumes (60 and 120 seconds) of foam rolling of the hamstrings during the inter‐set rest period on repetition performance of the knee extension exercise. Methods Twenty‐five recreationally active females were recruited for the study (27.8 ± 3.6 years, 168.4 ± 7.2 cm, 69.1 ± 10.2 kg, 27.2 ± 2.1 m2/kg). Initially, subjects underwent a ten‐repetition maximum testing and retesting, respectively. Thereafter, the experiment involved three sets of knee extensions with a pre‐determined 10 RM load to concentric failure with the goal of completing the maximum number of repetitions. During the inter‐set rest period, either passive rest or foam rolling of different durations (60 and 120 seconds) in a randomized order was employed. Results Ninety‐five percent confidence intervals revealed dose‐dependent, detrimental effects, with more time spent foam rolling resulting in fewer repetitions (Cohen's d of 2.0 and 1.2 for 120 and 60 seconds, respectively, in comparison with passive rest). Conclusion The results of the present study suggest that more inter‐set foam rolling applied to the antagonist muscle group is detrimental to the ability to continually produce force. The finding that inter‐set foam rolling of the antagonist muscle group decreases maximum repetition performance has implications for foam rolling prescription and implementation, in both rehabilitation and athletic populations. Level of evidence 2b PMID:28217418
Monteiro, Estêvão Rios; Škarabot, Jakob; Vigotsky, Andrew D; Brown, Amanda Fernandes; Gomes, Thiago Matassoli; Novaes, Jefferson da Silva
2017-02-01
Foam rollers, or other similar devices, are a method for acutely increasing range of motion, but in contrast to static stretching, do not appear to have detrimental effects on neuromuscular performance. The purpose of this study was to investigate the effects of different volumes (60 and 120 seconds) of foam rolling of the hamstrings during the inter-set rest period on repetition performance of the knee extension exercise. Twenty-five recreationally active females were recruited for the study (27.8 ± 3.6 years, 168.4 ± 7.2 cm, 69.1 ± 10.2 kg, 27.2 ± 2.1 m(2)/kg). Initially, subjects underwent a ten-repetition maximum testing and retesting, respectively. Thereafter, the experiment involved three sets of knee extensions with a pre-determined 10 RM load to concentric failure with the goal of completing the maximum number of repetitions. During the inter-set rest period, either passive rest or foam rolling of different durations (60 and 120 seconds) in a randomized order was employed. Ninety-five percent confidence intervals revealed dose-dependent, detrimental effects, with more time spent foam rolling resulting in fewer repetitions (Cohen's d of 2.0 and 1.2 for 120 and 60 seconds, respectively, in comparison with passive rest). The results of the present study suggest that more inter-set foam rolling applied to the antagonist muscle group is detrimental to the ability to continually produce force. The finding that inter-set foam rolling of the antagonist muscle group decreases maximum repetition performance has implications for foam rolling prescription and implementation, in both rehabilitation and athletic populations. 2b.
The inverse maximum dynamic flow problem
BAGHERIAN; Mehri
2010-01-01
We consider the inverse maximum dynamic flow (IMDF) problem.IMDF problem can be described as: how to change the capacity vector of a dynamic network as little as possible so that a given feasible dynamic flow becomes a maximum dynamic flow.After discussing some characteristics of this problem,it is converted to a constrained minimum dynamic cut problem.Then an efficient algorithm which uses two maximum dynamic flow algorithms is proposed to solve the problem.
Loads in the design of flight vehicles
Simion TĂTARU
2010-09-01
Full Text Available The calculation of flight loads is a critical part of air vehicle design. On the other hand, the prediction of accurate loads is a sophisticated and complex process that requires skilled and experienced engineers. They must integrate results from wind tunnel tests, computer simulations, historical data and empirical formulations into a number of loads cases that provide a realistic assessment of the flight vehicle’s environment. Under these conditions, the vehicle must satisfy requirements imposed by regulatory agencies as part of the vehicle certification process.Loads and boundary conditions can be associated to either the finite element model or the underlying geometry. By associating loads and boundary conditions to the geometry the finite element model mesh and elements can be modified without redefining and applying the loads to the model. Loads and boundary conditions are associated to the model geometry by default.
Load Balancing Algorithm for Cache Cluster
刘美华; 古志民; 曹元大
2003-01-01
By the load definition of cluster, the request is regarded as granularity to compute load and implement the load balancing in cache cluster. First, the processing power of cache-node is studied from four aspects: network bandwidth, memory capacity, disk access rate and CPU usage. Then, the weighted load of cache-node is customized. Based on this, a load-balancing algorithm that can be applied to the cache cluster is proposed. Finally, Polygraph is used as a benchmarking tool to test the cache cluster possessing the load-balancing algorithm and the cache cluster with cache array routing protocol respectively. The results show the load-balancing algorithm can improve the performance of the cache cluster.
Critical plane approach to multiaxial variable amplitude fatigue loading
Yingyu Wang
2015-07-01
Full Text Available A new critical plane approach based on the modified Manson-Coffin curve method (MMCCM is presented in this paper for predicting fatigue lifetime under variable amplitude (VA multiaxial fatigue loading. The critical plane is assumed to coincide with that material plane experiencing the maximum variance of the resolved shear strain. Fatigue damage is hypothesized to be a function of both the amplitude of the resolved shear strain and the so-called critical plane stress ratio. The latter quantity depends on the mean value and the variance of the stress perpendicular to the critical plane as well as on the variance of the shear stress resolved along the direction experiencing the maximum variance of the resolved shear strain. Load cycles are counted from the resolved shear strain time history by using the classic rain flow counting method. Palmgren-Miner’s linear damage rule is applied to estimate cumulative fatigue damage. The accuracy and reliability of the proposed approach is checked by using several experimental data taken from the literature. The estimated fatigue lives based on the new approach are seen to be in sound agreement with the experimental results.
Maximum permissible voltage of YBCO coated conductors
Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)
2014-06-15
Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.
A piezoelectric-based infinite stiffness generation method for strain-type load sensors
Zhang, Shuwen; Shao, Shubao; Chen, Jie; Xu, Minglong
2015-11-01
Under certain application conditions like nanoindentation technology and the mechanical property measurement of soft materials, the elastic deformation of strain-type load sensors affects their displacement measurement accuracy. In this work, a piezoelectric-based infinite stiffness generation method for strain-type load sensors that compensates for this elastic deformation is presented. The piezoelectric material-based deformation compensation method is proposed. An Hottinger Baldwin Messtechnik GmbH (HBM) Z30A/50N load sensor acts as the foundation of the method presented in this work. The piezoelectric stack is selected based on its size, maximum deformation value, blocking force and stiffness. Then, a clamping and fixing structure is designed to integrate the HBM sensor with the piezoelectric stack. The clamping and fixing structure, piezoelectric stack and HBM load sensor comprise the sensing part of the enhanced load sensor. The load-deformation curve and the voltage-deformation curve of the enhanced load sensor are then investigated experimentally. Because a hysteresis effect exists in the piezoelectric structure, the relationship between the control signal and the deformation value of the piezoelectric material is nonlinear. The hysteresis characteristic in a quasi-static condition is studied and fitted using a quadratic polynomial, and its coefficients are analyzed to enable control signal prediction. Applied arithmetic based on current theory and the fitted data is developed to predict the control signal. Finally, the experimental effects of the proposed method are presented. It is shown that when a quasi-static load is exerted on this enhanced strain-type load sensor, the deformation is reduced and the equivalent stiffness appears to be almost infinite.
Load balancing by redundant decomposition and maping
de Ronde, J.F.; Schoneveld, A.; Sloot, P.M.A.
1997-01-01
In this paper a new methodology for load balancing parallel processes on parallel systems is proposed. The problem of load balancing is considered to be an NP-hard optimization task. Taking static parallel finite element applications as a case study, the benefits and losses that follow from applying
Load balancing by redundant decomposition and maping
de Ronde, J.F.; Schoneveld, A.; Sloot, P.M.A.
1997-01-01
In this paper a new methodology for load balancing parallel processes on parallel systems is proposed. The problem of load balancing is considered to be an NP-hard optimization task. Taking static parallel finite element applications as a case study, the benefits and losses that follow from applying
Dyrbye, Claes; Hansen, Svend Ole
pressure to structural response) and design criteria. Starting with an introduction of the wind load chain, the book moves on to meteorological considerations, atmospheric boundary layer, static wind load, dynamic wind load and scaling laws used in wind-tunnel tests. The dynamic wind load covers vibrations......Wind loads have to be taken into account when designing civil engineering structures. The wind load on structures can be systematised by means of the wind load chain: wind climate (global), terrain (wind at low height), aerodynamic response (wind load to pressure), mechanical response (wind...
Dyrbye, Claes; Hansen, Svend Ole
pressure to structural response) and design criteria. Starting with an introduction of the wind load chain, the book moves on to meteorological considerations, atmospheric boundary layer, static wind load, dynamic wind load and scaling laws used in wind-tunnel tests. The dynamic wind load covers vibrations......Wind loads have to be taken into account when designing civil engineering structures. The wind load on structures can be systematised by means of the wind load chain: wind climate (global), terrain (wind at low height), aerodynamic response (wind load to pressure), mechanical response (wind...
Propane spectral resolution enhancement by the maximum entropy method
Bonavito, N. L.; Stewart, K. P.; Hurley, E. J.; Yeh, K. C.; Inguva, R.
1990-01-01
The Burg algorithm for maximum entropy power spectral density estimation is applied to a time series of data obtained from a Michelson interferometer and compared with a standard FFT estimate for resolution capability. The propane transmittance spectrum was estimated by use of the FFT with a 2 to the 18th data sample interferogram, giving a maximum unapodized resolution of 0.06/cm. This estimate was then interpolated by zero filling an additional 2 to the 18th points, and the final resolution was taken to be 0.06/cm. Comparison of the maximum entropy method (MEM) estimate with the FFT was made over a 45/cm region of the spectrum for several increasing record lengths of interferogram data beginning at 2 to the 10th. It is found that over this region the MEM estimate with 2 to the 16th data samples is in close agreement with the FFT estimate using 2 to the 18th samples.
The optimal polarizations for achieving maximum contrast in radar images
Swartz, A. A.; Yueh, H. A.; Kong, J. A.; Novak, L. M.; Shin, R. T.
1988-01-01
There is considerable interest in determining the optimal polarizations that maximize contrast between two scattering classes in polarimetric radar images. A systematic approach is presented for obtaining the optimal polarimetric matched filter, i.e., that filter which produces maximum contrast between two scattering classes. The maximization procedure involves solving an eigenvalue problem where the eigenvector corresponding to the maximum contrast ratio is an optimal polarimetric matched filter. To exhibit the physical significance of this filter, it is transformed into its associated transmitting and receiving polarization states, written in terms of horizontal and vertical vector components. For the special case where the transmitting polarization is fixed, the receiving polarization which maximizes the contrast ratio is also obtained. Polarimetric filtering is then applies to synthetic aperture radar images obtained from the Jet Propulsion Laboratory. It is shown, both numerically and through the use of radar imagery, that maximum image contrast can be realized when data is processed with the optimal polarimeter matched filter.
Proscriptive Bayesian Programming and Maximum Entropy: a Preliminary Study
Koike, Carla Cavalcante
2008-11-01
Some problems found in robotics systems, as avoiding obstacles, can be better described using proscriptive commands, where only prohibited actions are indicated in contrast to prescriptive situations, which demands that a specific command be specified. An interesting question arises regarding the possibility to learn automatically if proscriptive commands are suitable and which parametric function could be better applied. Lately, a great variety of problems in robotics domain are object of researches using probabilistic methods, including the use of Maximum Entropy in automatic learning for robot control systems. This works presents a preliminary study on automatic learning of proscriptive robot control using maximum entropy and using Bayesian Programming. It is verified whether Maximum entropy and related methods can favour proscriptive commands in an obstacle avoidance task executed by a mobile robot.
Maximum Correntropy Unscented Kalman Filter for Spacecraft Relative State Estimation.
Liu, Xi; Qu, Hua; Zhao, Jihong; Yue, Pengcheng; Wang, Meng
2016-09-20
A new algorithm called maximum correntropy unscented Kalman filter (MCUKF) is proposed and applied to relative state estimation in space communication networks. As is well known, the unscented Kalman filter (UKF) provides an efficient tool to solve the non-linear state estimate problem. However, the UKF usually plays well in Gaussian noises. Its performance may deteriorate substantially in the presence of non-Gaussian noises, especially when the measurements are disturbed by some heavy-tailed impulsive noises. By making use of the maximum correntropy criterion (MCC), the proposed algorithm can enhance the robustness of UKF against impulsive noises. In the MCUKF, the unscented transformation (UT) is applied to obtain a predicted state estimation and covariance matrix, and a nonlinear regression method with the MCC cost is then used to reformulate the measurement information. Finally, the UT is adopted to the measurement equation to obtain the filter state and covariance matrix. Illustrative examples demonstrate the superior performance of the new algorithm.
Generalised maximum entropy and heterogeneous technologies
Oude Lansink, A.G.J.M.
1999-01-01
Generalised maximum entropy methods are used to estimate a dual model of production on panel data of Dutch cash crop farms over the period 1970-1992. The generalised maximum entropy approach allows a coherent system of input demand and output supply equations to be estimated for each farm in the sam
20 CFR 229.48 - Family maximum.
2010-04-01
... month on one person's earnings record is limited. This limited amount is called the family maximum. The family maximum used to adjust the social security overall minimum rate is based on the employee's Overall..., when any of the persons entitled to benefits on the insured individual's compensation would, except...
S. Ribeiro
2009-06-01
Full Text Available Este trabalho mostra a influência da forma e do processo de obtenção do entalhe na estabilidade da propagação de trinca em materiais cerâmicos de microestrutura heterogênea e conseqüentemente, na carga máxima e energia de fratura quando esses materiais são submetidos ao carregamento utilizando o método da cunha. Foram preparadas argamassas com cimento Portland, areia e água, que foram moldadas, curadas a 25 ºC por 7 dias e secadas a 50 ºC por 48 h. Foram estudadas duas proporções (dosagens ou traços de areia:cimento de 3:1 e 2:1. Foram testados dois tipos de entalhe: um com perfil quadrado da ponta e outro em "V" com ângulo de 60º. Os entalhes de formato quadrado foram obtidos de duas formas: produzidos mecanicamente a partir de disco diamantado e outro na própria moldagem das amostras. Para produzir as amostras entalhadas e ranhuradas já na moldagem, foi desenvolvido um molde de PVC munido de lâminas de aço internas. A partir dos testes preliminares foram estabelecidas as condições de propagação estável da trinca. A trinca percorre um plano imaginário definido pelas ranhuras laterais da amostra. Os resultados mostraram que o entalhe que proporciona melhores condições de estabilidade de propagação de trinca é o de forma em "V", obtido durante o processo de moldagem das amostras.This paper discusses how the shape and preparation of the notch affect crack propagation in ceramic materials with heterogeneous microstructures and, as a result, the maximum load and fracture energy when these materials are subjected to loads using the wedge splitting test. Mortars were prepared with Portland cement, sand and water, which were mixed, molded, and cured at 25 ºC for seven days. After curing, the samples were dried at 55 ºC for 48 h. Two mortar compositions were prepared with proportions of sand:cement of 3:1 and 2:1. Two types of notches were tested: one with a square-tipped profile and the other V-shaped with a 60º
14 CFR 25.363 - Side load on engine and auxiliary power unit mounts.
2010-01-01
... § 25.363 Side load on engine and auxiliary power unit mounts. (a) Each engine and auxiliary power unit... the side load on the engine and auxiliary power unit mount, at least equal to the maximum load factor... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Side load on engine and auxiliary...
Duality of Maximum Entropy and Minimum Divergence
Shinto Eguchi
2014-06-01
Full Text Available We discuss a special class of generalized divergence measures by the use of generator functions. Any divergence measure in the class is separated into the difference between cross and diagonal entropy. The diagonal entropy measure in the class associates with a model of maximum entropy distributions; the divergence measure leads to statistical estimation via minimization, for arbitrarily giving a statistical model. The dualistic relationship between the maximum entropy model and the minimum divergence estimation is explored in the framework of information geometry. The model of maximum entropy distributions is characterized to be totally geodesic with respect to the linear connection associated with the divergence. A natural extension for the classical theory for the maximum likelihood method under the maximum entropy model in terms of the Boltzmann-Gibbs-Shannon entropy is given. We discuss the duality in detail for Tsallis entropy as a typical example.
An application of Hamiltonian neurodynamics using Pontryagin's Maximum (Minimum) Principle.
Koshizen, T; Fulcher, J
1995-12-01
Classical optimal control methods, notably Pontryagin's Maximum (Minimum) Principle (PMP) can be employed, together with Hamiltonians, to determine optimal system weights in Artificial Neural dynamical systems. A new learning rule based on weight equations derived using PMP is shown to be suitable for both discrete- and continuous-time systems, and moreover, can also be applied to feedback networks. Preliminary testing shows that this PMP learning rule compares favorably with Standard BackPropagations (SBP) on the XOR problem.
Maximum-likelihood estimation prevents unphysical Mueller matrices
Aiello, A; Voigt, D; Woerdman, J P
2005-01-01
We show that the method of maximum-likelihood estimation, recently introduced in the context of quantum process tomography, can be applied to the determination of Mueller matrices characterizing the polarization properties of classical optical systems. Contrary to linear reconstruction algorithms, the proposed method yields physically acceptable Mueller matrices even in presence of uncontrolled experimental errors. We illustrate the method on the case of an unphysical measured Mueller matrix taken from the literature.
PNNL: A Supervised Maximum Entropy Approach to Word Sense Disambiguation
Tratz, Stephen C.; Sanfilippo, Antonio P.; Gregory, Michelle L.; Chappell, Alan R.; Posse, Christian; Whitney, Paul D.
2007-06-23
In this paper, we described the PNNL Word Sense Disambiguation system as applied to the English All-Word task in Se-mEval 2007. We use a supervised learning approach, employing a large number of features and using Information Gain for dimension reduction. Our Maximum Entropy approach combined with a rich set of features produced results that are significantly better than baseline and are the highest F-score for the fined-grained English All-Words subtask.
Yuan, Y.; Greuner, H.; Böswirth, B.; Krieger, K.; Luo, G.-N.; Xu, H. Y.; Fu, B. Q.; Li, M.; Liu, W.
2013-02-01
Short pulse heat loads expected for vertical displacement events (VDEs) in ITER were applied in the high heat flux (HHF) test facility GLADIS at IPP-Garching onto samples of rolled W. Pulsed neutral beams with the central heat flux of 23 MW/m2 were applied for 0.5, 1.0 and 1.5 s, respectively. Rapid recrystallization of the adiabatically loaded 3 mm thick samples was observed when the pulse duration was up to 1.0 s. Grains grew markedly following recrystallization with increasing pulse length. The recrystallization temperature and temperature dependence of the recrystallized grain size were also investigated. The results showed that the recrystallization temperature of the W grade was around 2480 °C under the applied heat loading condition, which was nearly 1150 °C higher than the conventional recrystallization temperature, and the grains were much finer. A linear relationship between the logarithm of average grain size (ln d) and the inverse of maximum surface temperature (1/Tmax) was found and accordingly the activation energy for grain growth in temperature evolution up to Tmax in 1.5 s of the short pulse HHF load was deduced to be 4.1 eV. This provided an effective clue to predict the structure evolution under short pulse HHF loads.
Robust Hammerstein Adaptive Filtering under Maximum Correntropy Criterion
Zongze Wu
2015-10-01
Full Text Available The maximum correntropy criterion (MCC has recently been successfully applied to adaptive filtering. Adaptive algorithms under MCC show strong robustness against large outliers. In this work, we apply the MCC criterion to develop a robust Hammerstein adaptive filter. Compared with the traditional Hammerstein adaptive filters, which are usually derived based on the well-known mean square error (MSE criterion, the proposed algorithm can achieve better convergence performance especially in the presence of impulsive non-Gaussian (e.g., α-stable noises. Additionally, some theoretical results concerning the convergence behavior are also obtained. Simulation examples are presented to confirm the superior performance of the new algorithm.
OIL MONITORING DIAGNOSTIC CRITERIONS BASED ON MAXIMUM ENTROPY PRINCIPLE
Huo Hua; Li Zhuguo; Xia Yanchun
2005-01-01
A method of applying maximum entropy probability density estimation approach to constituting diagnostic criterions of oil monitoring data is presented. The method promotes the precision of diagnostic criterions for evaluating the wear state of mechanical facilities, and judging abnormal data. According to the critical boundary points defined, a new measure on monitoring wear state and identifying probable wear faults can be got. The method can be applied to spectrometric analysis and direct reading ferrographic analysis. On the basis of the analysis and discussion of two examples of 8NVD48A-2U diesel engines, the practicality is proved to be an effective method in oil monitoring.
A maximum power point tracking algorithm for photovoltaic applications
Nelatury, Sudarshan R.; Gray, Robert
2013-05-01
The voltage and current characteristic of a photovoltaic (PV) cell is highly nonlinear and operating a PV cell for maximum power transfer has been a challenge for a long time. Several techniques have been proposed to estimate and track the maximum power point (MPP) in order to improve the overall efficiency of a PV panel. A strategic use of the mean value theorem permits obtaining an analytical expression for a point that lies in a close neighborhood of the true MPP. But hitherto, an exact solution in closed form for the MPP is not published. This problem can be formulated analytically as a constrained optimization, which can be solved using the Lagrange method. This method results in a system of simultaneous nonlinear equations. Solving them directly is quite difficult. However, we can employ a recursive algorithm to yield a reasonably good solution. In graphical terms, suppose the voltage current characteristic and the constant power contours are plotted on the same voltage current plane, the point of tangency between the device characteristic and the constant power contours is the sought for MPP. It is subject to change with the incident irradiation and temperature and hence the algorithm that attempts to maintain the MPP should be adaptive in nature and is supposed to have fast convergence and the least misadjustment. There are two parts in its implementation. First, one needs to estimate the MPP. The second task is to have a DC-DC converter to match the given load to the MPP thus obtained. Availability of power electronics circuits made it possible to design efficient converters. In this paper although we do not show the results from a real circuit, we use MATLAB to obtain the MPP and a buck-boost converter to match the load. Under varying conditions of load resistance and irradiance we demonstrate MPP tracking in case of a commercially available solar panel MSX-60. The power electronics circuit is simulated by PSIM software.
冯涛; 王同功
2013-01-01
以三相感应电动机为分析对象,针对感应电动机动态过程复杂的问题,利用MATLAB软件对三相感应电动机突加阶跃负载时的动态过程和瞬间断电重新投入电网时的动态过程进行仿真,得出仿真曲线及结论.%To analyze three-phase induction motor for the complex problem of the induction motor dynamic process, in which the motor was suddenly applied step load and rejoined the power grid after momentary power failure. It was simulated with MATLAB software, and the simulation curves and conclusions were finally drew.
Yuan, Y. [Laboratory of Advanced Materials, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Greuner, H.; Böswirth, B.; Krieger, K. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, 85748 Garching (Germany); Luo, G.-N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Xu, H.Y.; Fu, B.Q.; Li, M. [Laboratory of Advanced Materials, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, W., E-mail: liuw@mail.tsinghua.edu.cn [Laboratory of Advanced Materials, Department of Material Science and Engineering, Tsinghua University, Beijing 100084 (China)
2013-02-15
Highlights: ► Recrystallization temperature of a rolled W was ∼2480 °C under applied HHF loads. ► Fine grains were obtained under HHF loads with appropriate short pulse length. ► With increasing pulse length, the recrystallized grains significantly grew larger. ► A linear relationship between ln d and 1/T{sub max} was found. ► Activation energy for grain growth in T evolution up to T{sub max} in 1.5 s was obtained. -- Abstract: Short pulse heat loads expected for vertical displacement events (VDEs) in ITER were applied in the high heat flux (HHF) test facility GLADIS at IPP-Garching onto samples of rolled W. Pulsed neutral beams with the central heat flux of 23 MW/m{sup 2} were applied for 0.5, 1.0 and 1.5 s, respectively. Rapid recrystallization of the adiabatically loaded 3 mm thick samples was observed when the pulse duration was up to 1.0 s. Grains grew markedly following recrystallization with increasing pulse length. The recrystallization temperature and temperature dependence of the recrystallized grain size were also investigated. The results showed that the recrystallization temperature of the W grade was around 2480 °C under the applied heat loading condition, which was nearly 1150 °C higher than the conventional recrystallization temperature, and the grains were much finer. A linear relationship between the logarithm of average grain size (ln d) and the inverse of maximum surface temperature (1/T{sub max}) was found and accordingly the activation energy for grain growth in temperature evolution up to T{sub max} in 1.5 s of the short pulse HHF load was deduced to be 4.1 eV. This provided an effective clue to predict the structure evolution under short pulse HHF loads.
Training Concept, Evolution Time, and the Maximum Entropy Production Principle
Alexey Bezryadin
2016-04-01
Full Text Available The maximum entropy production principle (MEPP is a type of entropy optimization which demands that complex non-equilibrium systems should organize such that the rate of the entropy production is maximized. Our take on this principle is that to prove or disprove the validity of the MEPP and to test the scope of its applicability, it is necessary to conduct experiments in which the entropy produced per unit time is measured with a high precision. Thus we study electric-field-induced self-assembly in suspensions of carbon nanotubes and realize precise measurements of the entropy production rate (EPR. As a strong voltage is applied the suspended nanotubes merge together into a conducting cloud which produces Joule heat and, correspondingly, produces entropy. We introduce two types of EPR, which have qualitatively different significance: global EPR (g-EPR and the entropy production rate of the dissipative cloud itself (DC-EPR. The following results are obtained: (1 As the system reaches the maximum of the DC-EPR, it becomes stable because the applied voltage acts as a stabilizing thermodynamic potential; (2 We discover metastable states characterized by high, near-maximum values of the DC-EPR. Under certain conditions, such efficient entropy-producing regimes can only be achieved if the system is allowed to initially evolve under mildly non-equilibrium conditions, namely at a reduced voltage; (3 Without such a “training” period the system typically is not able to reach the allowed maximum of the DC-EPR if the bias is high; (4 We observe that the DC-EPR maximum is achieved within a time, Te, the evolution time, which scales as a power-law function of the applied voltage; (5 Finally, we present a clear example in which the g-EPR theoretical maximum can never be achieved. Yet, under a wide range of conditions, the system can self-organize and achieve a dissipative regime in which the DC-EPR equals its theoretical maximum.
Hendriksen, Payana; Elmgreen, Katrine; Ladewig, Jan
2011-01-01
The traditional way to train horses is by the application of negative reinforcement (NR). In the past few years, however, the use of positive reinforcement (PR) has become more common. To evaluate the effectiveness and the possible stressor effect of the 2 training methods, 12 horses showing severe...... trailer-loading problems were selected and exposed to trailer-loading. They were randomly assigned to one of the 2 methods. NR consisted of various degrees of pressure (lead rope pulling, whip tapping). Pressure was removed as soon as the horse complied. PR horses were exposed to clicker training...... and taught to follow a target into the trailer. Heart rate (HR) was recorded every 5 seconds and behavior denoting discomfort was observed using one-zero sampling with 10 seconds sampling intervals. Training was completed when the horse could enter the trailer upon a signal, or was terminated after a maximum...
Hai CHEN; Meng-lian ZHAO; Xiao-bo WU; Xiao-lang YAN
2008-01-01
This paper presents a multi-mode control scheme for a soft-switched flyback converter to achieve high efficiency and excellent load regulation over the entire load range. At heavy load, critical conduction mode with valley switching (CCMVS) is employed to realize soft switching so as to reduce turn-on loss of power switch as well as conducted electromagnetic interference (EMI). At light load, the converter operates in discontinuous conduction mode (DCM) with valley switching and adaptive off-time control (AOT) to limit the switching frequency range and maintain load regulation. At extremely light load or in standby mode,burst mode operation is adopted to provide low power consumption through reducing both switching frequency and static power dissipation of the controller. The multi-mode control is implemented by an oscillator whose pulse duration is adjusted by output feedback. An accurate valley switching control circuit guarantees the minimum turn-on voltage drop of power switch. The pro-totype of the controller IC was fabricated in a 1.5um BiCMOS process and applied to a 310 V/20 V, 90 W flyback DC/DC converter circuitry. Experimental results showed that all expected functions were realized successfully. The flyback converter achieved a high efficiency of over 80% from full load down to 2.5 W, with the maximum reaching 88.8%, while the total power consumption in standby mode was about 300 mW.
An improved maximum power point tracking method for photovoltaic systems
Tafticht, T.; Agbossou, K.; Doumbia, M.L.; Cheriti, A. [Institut de recherche sur l' hydrogene, Departement de genie electrique et genie informatique, Universite du Quebec a Trois-Rivieres, C.P. 500, Trois-Rivieres (QC) (Canada)
2008-07-15
In most of the maximum power point tracking (MPPT) methods described currently in the literature, the optimal operation point of the photovoltaic (PV) systems is estimated by linear approximations. However these approximations can lead to less than optimal operating conditions and hence reduce considerably the performances of the PV system. This paper proposes a new approach to determine the maximum power point (MPP) based on measurements of the open-circuit voltage of the PV modules, and a nonlinear expression for the optimal operating voltage is developed based on this open-circuit voltage. The approach is thus a combination of the nonlinear and perturbation and observation (P and O) methods. The experimental results show that the approach improves clearly the tracking efficiency of the maximum power available at the output of the PV modules. The new method reduces the oscillations around the MPP, and increases the average efficiency of the MPPT obtained. The new MPPT method will deliver more power to any generic load or energy storage media. (author)
Critical Buckling Load on Large Spherical Shells
Wedellsborg, B. W.
1962-01-01
Approximate evaluation for watertanks, hortonspheres, vapor containers, containment vessels for nuclear reactors, and so forth, has been computed, taking into account out-of-roundness and local flattened areas; graphs have been plotted giving critical buckling load as function of maximum radial...
Applied load on the horse's back under racing conditions.
Geser-von Peinen, Katja; Latif, Selma N; Wiestner, Thomas; Bitschnau, Caroline; Renk, Brigitte; Weishaupt, Michael A
2013-12-01
With the intention of limiting the weight on horses' backs and guaranteeing maximal freedom of movement, commonly used racing saddles are small and have minimal cushioning. Poor saddle cushioning may limit performance or even affect soundness of the back. The aim of this study was to measure the pressure under an average racing saddle ridden by a jockey at racing speed. Saddle pressure using a medium-sized racing saddle (length 37 cm, weight 450 g) was measured in five actively racing Thoroughbred horses. All horses were trained at the same facility and ridden by their usual professional jockey, weighing 60 kg. The horses were ridden on a race track at canter (mean velocity, V1 ± standard deviation, SD: 7.7 ± 0.4m/s) and gallop (V2 ± SD: 14.0 ± 0.7 m/s). Maximal pressure was 134 kPa at V1 and 116 kPa at V2. Mean peak pressure was 73.6 kPa at V1 and 54.8 kPa at V2. The maximal total force did not differ between the two velocities and was approximately twice the jockey's bodyweight. The centre of pressure lateral range of motion differed significantly, with excursions of 23 mm at V1 and 37 mm at V2; longitudinal excursion was 13 mm for V1 and 14 mm for V2. The highest pressure (>35 kPa) was always localised along the spinous processes over an average length of 12.5 cm. It was concluded that racing saddles exert high peak pressures over bony prominences known to be sensitive to pressure. Copyright © 2013 Elsevier Ltd. All rights reserved.
Static Load Distribution in Ball Bearings
Ricci, Mario
2010-01-01
A numerical procedure for computing the internal loading distribution in statically loaded, single-row, angular-contact ball bearings when subjected to a known combined radial and thrust load is presented. The combined radial and thrust load must be applied in order to avoid tilting between inner and outer rings. The numerical procedure requires the iterative solution of Z + 2 simultaneous nonlinear equations - where Z is the number of the balls - to yield an exact solution for axial and radial deflections, and contact angles. Numerical results for a 218 angular-contact ball bearing have been compared with those from the literature and show significant differences in the magnitudes of the ball loads, contact angles, and the extent of the loading zone.
A dual method for maximum entropy restoration
Smith, C. B.
1979-01-01
A simple iterative dual algorithm for maximum entropy image restoration is presented. The dual algorithm involves fewer parameters than conventional minimization in the image space. Minicomputer test results for Fourier synthesis with inadequate phantom data are given.
Photoemission spectromicroscopy with MAXIMUM at Wisconsin
Ng, W.; Ray-Chaudhuri, A.K.; Cole, R.K.; Wallace, J.; Crossley, S.; Crossley, D.; Chen, G.; Green, M.; Guo, J.; Hansen, R.W.C.; Cerrina, F.; Margaritondo, G. (Dept. of Electrical Engineering, Dept. of Physics and Synchrotron Radiation Center, Univ. of Wisconsin, Madison (USA)); Underwood, J.H.; Korthright, J.; Perera, R.C.C. (Center for X-ray Optics, Accelerator and Fusion Research Div., Lawrence Berkeley Lab., CA (USA))
1990-06-01
We describe the development of the scanning photoemission spectromicroscope MAXIMUM at the Wisoncsin Synchrotron Radiation Center, which uses radiation from a 30-period undulator. The article includes a discussion of the first tests after the initial commissioning. (orig.).
19 CFR 114.23 - Maximum period.
2010-04-01
... 19 Customs Duties 1 2010-04-01 2010-04-01 false Maximum period. 114.23 Section 114.23 Customs... CARNETS Processing of Carnets § 114.23 Maximum period. (a) A.T.A. carnet. No A.T.A. carnet with a period of validity exceeding 1 year from date of issue shall be accepted. This period of validity cannot be...
Maximum-Likelihood Detection Of Noncoherent CPM
Divsalar, Dariush; Simon, Marvin K.
1993-01-01
Simplified detectors proposed for use in maximum-likelihood-sequence detection of symbols in alphabet of size M transmitted by uncoded, full-response continuous phase modulation over radio channel with additive white Gaussian noise. Structures of receivers derived from particular interpretation of maximum-likelihood metrics. Receivers include front ends, structures of which depends only on M, analogous to those in receivers of coherent CPM. Parts of receivers following front ends have structures, complexity of which would depend on N.
Probabilistic representation of duration of load effects in timber structures
Svensson, Staffan
2011-01-01
to be considered. These two cases are maximum load level exceeding load-carrying capacity and damage accumulation (caused by the load and its duration) leading to failure. The effect of both load intensity and load duration on the capacity of timber has been an area of large interest over the last decades...... models for the representation of damage accumulation in timber are considered. The parameters of these models are calibrated by the use of test data whereas uncertainties associated with the model formulation and limited sample size are considered. The DOL effect is usually taken into account in code...
Wenninger, R.; Albanese, R.; Ambrosino, R.; Arbeiter, F.; Aubert, J.; Bachmann, C.; Barbato, L.; Barrett, T.; Beckers, M.; Biel, W.; Boccaccini, L.; Carralero, D.; Coster, D.; Eich, T.; Fasoli, A.; Federici, G.; Firdaouss, M.; Graves, J.; Horacek, J.; Kovari, M.; Lanthaler, S.; Loschiavo, V.; Lowry, C.; Lux, H.; Maddaluno, G.; Maviglia, F.; Mitteau, R.; Neu, R.; Pfefferle, D.; Schmid, K.; Siccinio, M.; Sieglin, B.; Silva, C.; Snicker, A.; Subba, F.; Varje, J.; Zohm, H.
2017-04-01
For several reasons the challenge to keep the loads to the first wall within engineering limits is substantially higher in DEMO compared to ITER. Therefore the pre-conceptual design development for DEMO that is currently ongoing in Europe needs to be based on load estimates that are derived employing the most recent plasma edge physics knowledge. An initial assessment of the static wall heat load limit in DEMO infers that the steady state peak heat flux limit on the majority of the DEMO first wall should not be assumed to be higher than 1.0 MW m-2. This compares to an average wall heat load of 0.29 MW m-2 for the design {\\tt {EU}}{\\tt {~}}{\\tt {DEMO1}}{\\tt {~2015}} assuming a perfect homogeneous distribution. The main part of this publication concentrates on the development of first DEMO estimates for charged particle, radiation, fast particle (all static) and disruption heat loads. Employing an initial engineering wall design with clear optimization potential in combination with parameters for the flat-top phase (x-point configuration), loads up to 7 MW m-2 (penalty factor for tolerances etc not applied) have been calculated. Assuming a fraction of power radiated from the x-point region between 1/5 and 1/3, peaks of the total power flux density due to radiation of 0.6-0.8 MW m-2 are found in the outer baffle region. This first review of wall loads, and the associated limits in DEMO clearly underlines a significant challenge that necessitates substantial engineering efforts as well as a considerable consolidation of the associated physics basis.
SEXUAL DIMORPHISM OF MAXIMUM FEMORAL LENGTH
Pandya A M
2011-04-01
Full Text Available Sexual identification from the skeletal parts has medico legal and anthropological importance. Present study aims to obtain values of maximum femoral length and to evaluate its possible usefulness in determining correct sexual identification. Study sample consisted of 184 dry, normal, adult, human femora (136 male & 48 female from skeletal collections of Anatomy department, M. P. Shah Medical College, Jamnagar, Gujarat. Maximum length of femur was considered as maximum vertical distance between upper end of head of femur and the lowest point on femoral condyle, measured with the osteometric board. Mean Values obtained were, 451.81 and 417.48 for right male and female, and 453.35 and 420.44 for left male and female respectively. Higher value in male was statistically highly significant (P< 0.001 on both sides. Demarking point (D.P. analysis of the data showed that right femora with maximum length more than 476.70 were definitely male and less than 379.99 were definitely female; while for left bones, femora with maximum length more than 484.49 were definitely male and less than 385.73 were definitely female. Maximum length identified 13.43% of right male femora, 4.35% of right female femora, 7.25% of left male femora and 8% of left female femora. [National J of Med Res 2011; 1(2.000: 67-70
Kordheili, Reza Ahmadi; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna
2014-01-01
High penetration of photovoltaic panels in distribution grid can bring the grid to its operation limits. The main focus of the paper is to determine maximum photovoltaic penetration level in the grid. Three main criteria were investigated for determining maximum penetration level of PV panels...... for this grid: even distribution of PV panels, aggregation of panels at the beginning of each feeder, and aggregation of panels at the end of each feeder. Load modeling is done using Velander formula. Since PV generation is highest in the summer due to irradiation, a summer day was chosen to determine maximum...
Robertson, D.M.; Schladow, S.G.
2008-01-01
Salton Sea, California, like many other lakes, has become eutrophic because of excessive nutrient loading, primarily phosphorus (P). A Total Maximum Daily Load (TMDL) is being prepared for P to reduce the input of P to the Sea. In order to better understand how P-load reductions should affect the average annual water quality of this terminal saline lake, three different eutrophication programs (BATHTUB, WiLMS, and the Seepage Lake Model) were applied. After verifying that specific empirical models within these programs were applicable to this saline lake, each model was calibrated using water-quality and nutrient-loading data for 1999 and then used to simulate the effects of specific P-load reductions. Model simulations indicate that a 50% decrease in external P loading would decrease near-surface total phosphorus concentrations (TP) by 25-50%. Application of other empirical models demonstrated that this decrease in loading should decrease near-surface chlorophyll a concentrations (Chl a) by 17-63% and increase Secchi depths (SD) by 38-97%. The wide range in estimated responses in Chl a and SD were primarily caused by uncertainty in how non-algal turbidity would respond to P-load reductions. If only the models most applicable to the Salton Sea are considered, a 70-90% P-load reduction is required for the Sea to be classified as moderately eutrophic (trophic state index of 55). These models simulate steady-state conditions in the Sea; therefore, it is difficult to ascertain how long it would take for the simulated changes to occur after load reductions. ?? 2008 Springer Science+Business Media B.V.
Application of the J integral to fracture under mixed-mode loading. [MMJINT; 4330V steel
Riddle, R.A.
1981-06-01
The calculation of the J integral proved to be a successful method for characterizing the stress and displacement fields around a crack tip under mixed mode loading. A computer program was written to determine the symmetric and antisymmetric J integral quantities. The stress intensity factors from these J integral calculations were in excellent agreement with other calculations. The compact shear specimen used contains three loading holes, the load applied at the center hole being the opposite direction to the load applied at the two outer holes. For 7075-T6 aluminum, K/sub IIc/ was 1.9 times larger than K/sub Ic/. In the brittle photoelastic material K/sub IIc/ was less than K/sub Ic/. Failure of the 4330V steel compact shear specimens came as a result of the average shear stress in the region ahead of the crack tip exceeding the material flow shear stress. The experimental results suggest that the angle of crack growth is best predicted by the maximum tangential stress theory.
Methods and models for the residential load management in distribution networks
Molina Garcia, Angel
The main purpose of this thesis is the development of new tools to obtain and assess residential load control strategies. In this way, elemental load models to simulate electrical and thermal behaviors have been implemented and validated; an appropriate aggregation technique, based on kernel estimators, has been selected; and a load control strategy algorithm has been developed and applied on the air conditioning-heat pump individual loads, analyzing the control action effects from two viewpoints: customer (demand pattern changes, services...) and utility (resource optimization, profile demand modifications...). As a consequence, this integrated tool allows to know the flexibility degree of a specific residential demand profile, according to a target demand profile previously defined, by means of an optimum combination of forced connections and disconnections, taking into account the discomfort level maximum accepted by the customers. Electrical thermal storage appliances have also been studied. In this case, the day-valley periods are proposed as possible partial storage periods. This would involve to divide the actual storage periods into two partial periods, decreasing the thermal capacity necessities as well as the discharge period forecasts. A thermal study about this proposal has been developed, comparing the indoor temperatures in both cases. Finally, and taking into account the modifications suffered by the electrical market during these last years, the developed tools can be applied by utility and customer side, within an electrical sector (residential) which supposes around 25 per cent the total electrical demand.
High Power Disk Loaded Guide Load
Farkas, Z.D.; /SLAC
2006-02-22
A method to design a matching section from a smooth guide to a disk-loaded guide, using a variation of broadband matching, [1, 2] is described. Using this method, we show how to design high power loads. The load consists of a disk-loaded coaxial guide operating in the TE{sub 01}-mode. We use this mode because it has no electric field terminating on a conductor, has no axial currents, and has no current at the cylinder-disk interface. A high power load design that has -35 dB reflection and a 200 MHz, -20 dB bandwidth, is presented. It is expected that it will carry the 600 MW output peak power of the pulse compression network. We use coaxial geometry and stainless steel material to increase the attenuation per cell.
Neuromuscular fatigue during dynamic maximal strength and hypertrophic resistance loadings.
Walker, Simon; Davis, Lisa; Avela, Janne; Häkkinen, Keijo
2012-06-01
The purpose of this study was to compare the acute neuromuscular fatigue during dynamic maximal strength and hypertrophic loadings, known to cause different adaptations underlying strength gain during training. Thirteen healthy, untrained males performed two leg press loadings, one week apart, consisting of 15 sets of 1 repetition maximum (MAX) and 5 sets of 10 repetition maximums (HYP). Concentric load and muscle activity, electromyography (EMG) amplitude and median frequency, was assessed throughout each set. Additionally, maximal bilateral isometric force and muscle activity was assessed pre-, mid-, and up to 30 min post-loading. Concentric load during MAX was decreased after set 10 (Pmuscle activity during HYP loading. Copyright © 2011 Elsevier Ltd. All rights reserved.
Heat load tests of superconducting magnets vibrated electromagnetically for the Maglev train
Ohmori, J.; Nakao, H.; Yamashita, T.; Sanada, Y.; Shudou, M.; Kawai, M.; Fujita, M.; Terai, M.; Miura, A.
Superconducting magnets on Maglev trains vibrate due to harmonic ripples of electromagnetic flux generated by ground coils. Heat load caused by vibration in the magnet amounted to several tens of watts in the electromagnetic vibration test. This was mainly because a.c. loss was induced in the helium vessel housing the superconducting coil, due to relative vibration between the aluminium thermal shield and the coil. The heat load caused by vibration should be strictly restricted to less than 4W due to limited cryogenic refrigeration capacity. The heat load was tested using electromagnetic flux ripples for a superconducting magnet model of one coil which corresponds to 1/4 of an actual magnet. The flux ripples simulated the 6th harmonic of the actual ground levitation coil. Some ideas to reduce the heat load were tried for the magnet model, such as applying high resistance thermal radiation shielding, increasing rigidity of the vacuum vessel, and using high purity copper plating on the helium vessel. These ideas proved effective, and the maximum heat load due to vibration was held to less than 4 W per magnet for the one coil magnet model.
Incorporating residential AC load control into ancillary service markets: Measurement and settlement
Bode, Josh L.; Sullivan, Michael J.; Berghman, Dries; Eto, Joseph H.
2013-05-01
Many pre-existing air conditioner load control programs can provide valuable operational flexibility but have not been incorporated into electricity ancillary service markets or grid operations. Multiple demonstrations have shown that residential air conditioner (AC) response can deliver resources quickly and can provide contingency reserves. A key policy hurdle to be overcome before AC load control can be fully incorporated into markets is how to balance the accuracy, cost, and complexity of methods available for the settlement of load curtailment. Overcoming this hurdle requires a means for assessing the accuracy of shorter-term AC load control demand reduction estimation approaches in an unbiased manner. This paper applies such a method to compare the accuracy of approaches varying in cost and complexity ? including regression analysis, load matching and control group approaches ? using feeder data, household data and AC end-use data. We recommend a practical approach for settlement, relying on an annually updated set of tables, with pre-calculated reduction estimates. These tables allow users to look up the demand reduction per device based on daily maximum temperature, geographic region and hour of day, simplifying settlement and providing a solution to the policy problem presented in this paper.
The Biomechanical Effect of Loading Speed on Metal-on-UHMWPE Contact Mechanics.
Zdero, Radovan; Bagheri, Zahra S; Rezaey, Mojtaba; Schemitsch, Emil H; Bougherara, Habiba
2014-01-01
Ultra high molecular weight polyethylene (UHMWPE) is a material commonly used in total hip and knee joint replacements. Numerous studies have assessed the effect of its viscoelastic properties on phenomena such as creep, stress relaxation, and tensile stress. However, these investigations either use the complex 3D geometries of total hip and knee replacements or UHMWPE test objects on their own. No studies have directly measured the effect of vertical load application speed on the contact mechanics of a metal sphere indenting UHMWPE. To this end, a metal ball was used to apply vertical force to a series of UHMWPE flat plate specimens over a wide range of loading speeds, namely, 1, 20, 40, 60, 80, 100, and 120 mm/min. Pressure sensitive Fujifilm was placed at the interface to measure contact area. Experimental results showed that maximum contact force ranged from 3596 to 4520 N and was logarithmically related (R(2)=0.96) to loading speed. Average contact area ranged from 76.5 to 79.9 mm(2) and was linearly related (R(2)=0.56) to loading speed. Average contact stress ranged from 45.1 to 58.2 MPa and was logarithmically related (R(2)=0.95) to loading speed. All UHMWPE specimens displayed a circular area of permanent surface damage, which did not disappear with time. This study has practical implications for understanding the contact mechanics of hip and knee replacements for a variety of activities of daily living.
Global Maximum Power Point Tracking of Photovoltaic Array under Partial Shaded Conditions
G.Shobana, P. Sornadeepika, Dr. R. Ramaprabha
2013-07-01
Full Text Available Efficiency of the PV module can be improved by operating at its peak power point so that the maximum power can be delivered to the load under varying environmental conditions. This paper is mainly focused on the maximum power point tracking of solar photovoltaic array (PV under non uniform insolation conditions. A maximum power point tracker (MPPT is used for extracting the maximum power from the solar PV module and transferring that power to the load. The problem of maximum power point (MPP tracking becomes a problem when the array receives non uniform insolation. Cells under shade absorb a large amount of electric power generated by cells receiving high insolation and convert it into heat which may damage the low illuminated cells. To relieve the stress on shaded cells, bypass diodes are added across the modules. In such a case multiple peaks in voltagepower characteristics are observed. Classical MPPT methods are not effective due to their inability to discriminate between local and global maximum. In this paper, Global MPPT algorithm is proposed to track the global maximum power point of PV array under partial shaded conditions.
Triadic conceptual structure of the maximum entropy approach to evolution.
Herrmann-Pillath, Carsten; Salthe, Stanley N
2011-03-01
Many problems in evolutionary theory are cast in dyadic terms, such as the polar oppositions of organism and environment. We argue that a triadic conceptual structure offers an alternative perspective under which the information generating role of evolution as a physical process can be analyzed, and propose a new diagrammatic approach. Peirce's natural philosophy was deeply influenced by his reception of both Darwin's theory and thermodynamics. Thus, we elaborate on a new synthesis which puts together his theory of signs and modern Maximum Entropy approaches to evolution in a process discourse. Following recent contributions to the naturalization of Peircean semiosis, pointing towards 'physiosemiosis' or 'pansemiosis', we show that triadic structures involve the conjunction of three different kinds of causality, efficient, formal and final. In this, we accommodate the state-centered thermodynamic framework to a process approach. We apply this on Ulanowicz's analysis of autocatalytic cycles as primordial patterns of life. This paves the way for a semiotic view of thermodynamics which is built on the idea that Peircean interpretants are systems of physical inference devices evolving under natural selection. In this view, the principles of Maximum Entropy, Maximum Power, and Maximum Entropy Production work together to drive the emergence of information carrying structures, which at the same time maximize information capacity as well as the gradients of energy flows, such that ultimately, contrary to Schrödinger's seminal contribution, the evolutionary process is seen to be a physical expression of the Second Law.
Maximum-entropy probability distributions under Lp-norm constraints
Dolinar, S.
1991-01-01
Continuous probability density functions and discrete probability mass functions are tabulated which maximize the differential entropy or absolute entropy, respectively, among all probability distributions with a given L sub p norm (i.e., a given pth absolute moment when p is a finite integer) and unconstrained or constrained value set. Expressions for the maximum entropy are evaluated as functions of the L sub p norm. The most interesting results are obtained and plotted for unconstrained (real valued) continuous random variables and for integer valued discrete random variables. The maximum entropy expressions are obtained in closed form for unconstrained continuous random variables, and in this case there is a simple straight line relationship between the maximum differential entropy and the logarithm of the L sub p norm. Corresponding expressions for arbitrary discrete and constrained continuous random variables are given parametrically; closed form expressions are available only for special cases. However, simpler alternative bounds on the maximum entropy of integer valued discrete random variables are obtained by applying the differential entropy results to continuous random variables which approximate the integer valued random variables in a natural manner. All the results are presented in an integrated framework that includes continuous and discrete random variables, constraints on the permissible value set, and all possible values of p. Understanding such as this is useful in evaluating the performance of data compression schemes.
Constrained Maximum Likelihood Estimation for Two-Level Mean and Covariance Structure Models
Bentler, Peter M.; Liang, Jiajuan; Tang, Man-Lai; Yuan, Ke-Hai
2011-01-01
Maximum likelihood is commonly used for the estimation of model parameters in the analysis of two-level structural equation models. Constraints on model parameters could be encountered in some situations such as equal factor loadings for different factors. Linear constraints are the most common ones and they are relatively easy to handle in…
Effect of consolidation ratios on maximum dynamic shear modulus of sands
Yuan Xiaoming; Sun Jing; Sun Rui
2005-01-01
The dynamic shear modulus (DSM) is the most basic soil parameter in earthquake or other dynamic loading conditions and can be obtained through testing in the field or in the laboratory. The effect of consolidation ratios on the maximum DSM for two types of sand is investigated by using resonant column tests. And, an increment formula to obtain the maximum DSM for cases of consolidation ratio kc＞1 is presented. The results indicate that the maximum DSM rises rapidly when kc is near 1 and then slows down, which means that the power function of the consolidation ratio increment kc-1 can be used to describe the variation of the maximum DSM due to kc＞1. The results also indicate that the increase in the maximum DSM due to kc＞1 is significantly larger than that predicted by Hardin and Black's formula.
14 CFR 25.511 - Ground load: unsymmetrical loads on multiple-wheel units.
2010-01-01
... differential equal to 2/3 of the most unfavorable combination of diameter variations that is obtained when... tires— (1) The applied side or drag load factor, or both factors, at the center of gravity must be the most critical value up to 50 percent and 40 percent, respectively, of the limit side or drag load...
Cognitive load measurement as a means to advance cognitive load theory
Paas, F.; Tuovinen, J.E.; Tabbers, H.; van Gerven, P.W.M.
2003-01-01
This paper discusses cognitive load measurement techniques with regard to their contribution to cognitive load theory (CLT). CLT is concerned with the design of instructional methods that efficiently use people's limited cognitive processing capacity to apply acquired knowledge and skills to new
Janssen PJCM; Speijers GJA; CSR
1997-01-01
This report contains a basic step-to-step description of the procedure followed in the derivation of the human-toxicological Maximum Permissible Risk (MPR ; in Dutch: Maximum Toelaatbaar Risico, MTR) for soil contaminants. In recent years this method has been applied for a large number of compounds
Hadi Sefidgar
2014-06-01
Full Text Available in this paper, a fuzzy logic control (FLC is proposed for maximum power point tracking (MPPT in wind turbine connection to Permanent Magnet Synchronous Generator (PMSG. The proposed fuzzy logic controller tracks the maximum power point (MPP by measurements the load voltage and current. This controller calculates the load power and sent through the fuzzy logic system. The main goal of this paper is design of the fuzzy logic controller in the model of DC-DC converter (boost converter. This method allows the MPPT controller output (duty cycle adjusts the voltage input to the converter to track the maximum power point of the wind generator.
Maximum permissible voltage of YBCO coated conductors
Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.
2014-06-01
Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.
Computing Rooted and Unrooted Maximum Consistent Supertrees
van Iersel, Leo
2009-01-01
A chief problem in phylogenetics and database theory is the computation of a maximum consistent tree from a set of rooted or unrooted trees. A standard input are triplets, rooted binary trees on three leaves, or quartets, unrooted binary trees on four leaves. We give exact algorithms constructing rooted and unrooted maximum consistent supertrees in time O(2^n n^5 m^2 log(m)) for a set of m triplets (quartets), each one distinctly leaf-labeled by some subset of n labels. The algorithms extend to weighted triplets (quartets). We further present fast exact algorithms for constructing rooted and unrooted maximum consistent trees in polynomial space. Finally, for a set T of m rooted or unrooted trees with maximum degree D and distinctly leaf-labeled by some subset of a set L of n labels, we compute, in O(2^{mD} n^m m^5 n^6 log(m)) time, a tree distinctly leaf-labeled by a maximum-size subset X of L that all trees in T, when restricted to X, are consistent with.
Maximum magnitude earthquakes induced by fluid injection
McGarr, Arthur F.
2014-01-01
Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.
Maximum magnitude earthquakes induced by fluid injection
McGarr, A.
2014-02-01
Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.
Continuous firefly algorithm applied to PWR core pattern enhancement
Poursalehi, N., E-mail: npsalehi@yahoo.com [Engineering Department, Shahid Beheshti University, G.C., P.O. Box 1983963113, Tehran (Iran, Islamic Republic of); Zolfaghari, A.; Minuchehr, A.; Moghaddam, H.K. [Engineering Department, Shahid Beheshti University, G.C., P.O. Box 1983963113, Tehran (Iran, Islamic Republic of)
2013-05-15
Highlights: ► Numerical results indicate the reliability of CFA for the nuclear reactor LPO. ► The major advantages of CFA are its light computational cost and fast convergence. ► Our experiments demonstrate the ability of CFA to obtain the near optimal loading pattern. -- Abstract: In this research, the new meta-heuristic optimization strategy, firefly algorithm, is developed for the nuclear reactor loading pattern optimization problem. Two main goals in reactor core fuel management optimization are maximizing the core multiplication factor (K{sub eff}) in order to extract the maximum cycle energy and minimizing the power peaking factor due to safety constraints. In this work, we define a multi-objective fitness function according to above goals for the core fuel arrangement enhancement. In order to evaluate and demonstrate the ability of continuous firefly algorithm (CFA) to find the near optimal loading pattern, we developed CFA nodal expansion code (CFANEC) for the fuel management operation. This code consists of two main modules including CFA optimization program and a developed core analysis code implementing nodal expansion method to calculate with coarse meshes by dimensions of fuel assemblies. At first, CFA is applied for the Foxholes test case with continuous variables in order to validate CFA and then for KWU PWR using a decoding strategy for discrete variables. Results indicate the efficiency and relatively fast convergence of CFA in obtaining near optimal loading pattern with respect to considered fitness function. At last, our experience with the CFA confirms that the CFA is easy to implement and reliable.
Experimental investigation of bond strength under high loading rates
Michal, Mathias; Keuser, Manfred; Solomos, George; Peroni, Marco; Larcher, Martin; Esteban, Beatriz
2015-09-01
The structural behaviour of reinforced concrete is governed significantly by the transmission of forces between steel and concrete. The bond is of special importance for the overlapping joint and anchoring of the reinforcement, where rigid bond is required. It also plays an important role in the rotational capacity of plastic hinges, where a ductile bond behaviour is preferable. Similar to the mechanical properties of concrete and steel also the characteristics of their interaction changes with the velocity of the applied loading. For smooth steel bars with its main bond mechanisms of adhesion and friction, nearly no influence of loading rate is reported in literature. In contrast, a high rate dependence can be found for the nowadays mainly used deformed bars. For mechanical interlock, where ribs of the reinforcing steel are bracing concrete material surrounding the bar, one reason can be assumed to be in direct connection with the increase of concrete compressive strength. For splitting failure of bond, characterized by the concrete tensile strength, an even higher dynamic increase is observed. For the design of Structures exposed to blast or impact loading the knowledge of a rate dependent bond stress-slip relationship is required to consider safety and economical aspects at the same time. The bond behaviour of reinforced concrete has been investigated with different experimental methods at the University of the Bundeswehr Munich (UniBw) and the Joint Research Centre (JRC) in Ispra. Both static and dynamic tests have been carried out, where innovative experimental apparatuses have been used. The bond stress-slip relationship and maximum pull-out-forces for varying diameter of the bar, concrete compressive strength and loading rates have been obtained. It is expected that these experimental results will contribute to a better understanding of the rate dependent bond behaviour and will serve for calibration of numerical models.
Experimental investigation of bond strength under high loading rates
Michal Mathias
2015-01-01
Full Text Available The structural behaviour of reinforced concrete is governed significantly by the transmission of forces between steel and concrete. The bond is of special importance for the overlapping joint and anchoring of the reinforcement, where rigid bond is required. It also plays an important role in the rotational capacity of plastic hinges, where a ductile bond behaviour is preferable. Similar to the mechanical properties of concrete and steel also the characteristics of their interaction changes with the velocity of the applied loading. For smooth steel bars with its main bond mechanisms of adhesion and friction, nearly no influence of loading rate is reported in literature. In contrast, a high rate dependence can be found for the nowadays mainly used deformed bars. For mechanical interlock, where ribs of the reinforcing steel are bracing concrete material surrounding the bar, one reason can be assumed to be in direct connection with the increase of concrete compressive strength. For splitting failure of bond, characterized by the concrete tensile strength, an even higher dynamic increase is observed. For the design of Structures exposed to blast or impact loading the knowledge of a rate dependent bond stress-slip relationship is required to consider safety and economical aspects at the same time. The bond behaviour of reinforced concrete has been investigated with different experimental methods at the University of the Bundeswehr Munich (UniBw and the Joint Research Centre (JRC in Ispra. Both static and dynamic tests have been carried out, where innovative experimental apparatuses have been used. The bond stress-slip relationship and maximum pull-out-forces for varying diameter of the bar, concrete compressive strength and loading rates have been obtained. It is expected that these experimental results will contribute to a better understanding of the rate dependent bond behaviour and will serve for calibration of numerical models.
Guimaraes, Flavio Borsato; Nasser, Ivana Costa [Wise Systems, Sao Paulo, SP (Brazil); Andrade, Danielle Bueno de; Machado, Renato Simoes; Morozowski Filho, Marciano [Empresa de Pesquisa Energetica (EPE), Rio de Janeiro, RJ (Brazil)
2010-07-01
Planning the future hydro capacity in Brazil includes considering power reinforcements in the peak hours due to the increasing numbers of run-of-river plants. It means that the Brazilian's reservoir profile has been changing over the years from five years regularization to monthly regularization. This article presents a deterministic methodology to evaluate the capacity reserve of the Brazilian power system. It is based on the 'capacity reserve margin' calculation done by a monthly comparison between peak availability and maximum peak load. This methodology was applied to the Decennial Energy Expansion Plan 2019 (PDE 2019) and its final results are shown here through Peak Balances considering different operation conditions and the whole inflows historical records. Additionally, it is presented a suggestion about the evolution of peak evaluation criteria to be applied to the Brazilian power system on its expansion planning. (author)
Deflection and maximum load of microfiltration membrane sieve made with silicon micromachining
Rijn, van Cees; Wekken, van der Michiel; Nijdam, Wietze; Elwenspoek, Miko
1997-01-01
With the use of silicon micromachining, an inorganic membrane sieve for microfiltration has been constructed having a silicon nitride membrane layer with thickness typically 1 ¿m and perforations typically between 0.5 ¿m and 10 ¿m in diameter. As a support a ¿100¿-silicon wafer with openings of 1000
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...
MODEL PREDICTIVE CONTROL FOR PHOTOVOLTAIC STATION MAXIMUM POWER POINT TRACKING SYSTEM
I. Elzein
2015-01-01
Full Text Available The purpose of this paper is to present an alternative maximum power point tracking, MPPT, algorithm for a photovoltaic module, PVM, to produce the maximum power, Pmax, using the optimal duty ratio, D, for different types of converters and load matching.We present a state-based approach to the design of the maximum power point tracker for a stand-alone photovoltaic power generation system. The system under consideration consists of a solar array with nonlinear time-varying characteristics, a step-up converter with appropriate filter.The proposed algorithm has the advantages of maximizing the efficiency of the power utilization, can be integrated to other MPPT algorithms without affecting the PVM performance, is excellent for Real-Time applications and is a robust analytical method, different from the traditional MPPT algorithms which are more based on trial and error, or comparisons between present and past states. The procedure to calculate the optimal duty ratio for a buck, boost and buck-boost converters, to transfer the maximum power from a PVM to a load, is presented in the paper. Additionally, the existence and uniqueness of optimal internal impedance, to transfer the maximum power from a photovoltaic module using load matching, is proved.
Vector control structure of an asynchronous motor at maximum torque
Chioncel, C. P.; Tirian, G. O.; Gillich, N.; Raduca, E.
2016-02-01
Vector control methods offer the possibility to gain high performance, being widely used. Certain applications require an optimum control in limit operating conditions, as, at maximum torque, that is not always satisfied. The paper presents how the voltage and the frequency for an asynchronous machine (ASM) operating at variable speed are determinate, with an accent on the method that keeps the rotor flux constant. The simulation analyses consider three load types: variable torque and speed, variable torque and constant speed, constant torque and variable speed. The final values of frequency and voltage are obtained through the proposed control schemes with one controller using the simulation language based on the Maple module. The dynamic analysis of the system is done for the case with P and PI controller and allows conclusions on the proposed method, which can have different applications, as the ASM in wind turbines.
Small scale wind energy harvesting with maximum power tracking
Joaquim Azevedo
2015-07-01
Full Text Available It is well-known that energy harvesting from wind can be used to power remote monitoring systems. There are several studies that use wind energy in small-scale systems, mainly with wind turbine vertical axis. However, there are very few studies with actual implementations of small wind turbines. This paper compares the performance of horizontal and vertical axis wind turbines for energy harvesting on wireless sensor network applications. The problem with the use of wind energy is that most of the time the wind speed is very low, especially at urban areas. Therefore, this work includes a study on the wind speed distribution in an urban environment and proposes a controller to maximize the energy transfer to the storage systems. The generated power is evaluated by simulation and experimentally for different load and wind conditions. The results demonstrate the increase in efficiency of wind generators that use maximum power transfer tracking, even at low wind speeds.
Livingston, Richard A.; Jin, Shuang
2005-05-01
Bridges and other civil structures can exhibit nonlinear and/or chaotic behavior under ambient traffic or wind loadings. The probability density function (pdf) of the observed structural responses thus plays an important role for long-term structural health monitoring, LRFR and fatigue life analysis. However, the actual pdf of such structural response data often has a very complicated shape due to its fractal nature. Various conventional methods to approximate it can often lead to biased estimates. This paper presents recent research progress at the Turner-Fairbank Highway Research Center of the FHWA in applying a novel probabilistic scaling scheme for enhanced maximum entropy evaluation to find the most unbiased pdf. The maximum entropy method is applied with a fractal interpolation formulation based on contraction mappings through an iterated function system (IFS). Based on a fractal dimension determined from the entire response data set by an algorithm involving the information dimension, a characteristic uncertainty parameter, called the probabilistic scaling factor, can be introduced. This allows significantly enhanced maximum entropy evaluation through the added inferences about the fine scale fluctuations in the response data. Case studies using the dynamic response data sets collected from a real world bridge (Commodore Barry Bridge, PA) and from the simulation of a classical nonlinear chaotic system (the Lorenz system) are presented in this paper. The results illustrate the advantages of the probabilistic scaling method over conventional approaches for finding the unbiased pdf especially in the critical tail region that contains the larger structural responses.
Application of Artificial Bee Colony Algorithm to Maximum Likelihood DOA Estimation
Zhicheng Zhang; Jun Lin; Yaowu Shi
2013-01-01
Maximum Likelihood (ML) method has an excellent performance for Direction-Of-Arrival (DOA) estimation,but a multidimensional nonlinear solution search is required which complicates the computation and prevents the method from practical use.To reduce the high computational burden of ML method and make it more suitable to engineering applications,we apply the Artificial Bee Colony (ABC) algorithm to maximize the likelihood function for DOA estimation.As a recently proposed bio-inspired computing algorithm,ABC algorithm is originally used to optimize multivariable functions by imitating the behavior of bee colony finding excellent nectar sources in the nature environment.It offers an excellent alternative to the conventional methods in ML-DOA estimation.The performance of ABC-based ML and other popular meta-heuristic-based ML methods for DOA estimation are compared for various scenarios of convergence,Signal-to-Noise Ratio (SNR),and number of iterations.The computation loads of ABC-based ML and the conventional ML methods for DOA estimation are also investigated.Simulation results demonstrate that the proposed ABC based method is more efficient in computation and statistical performance than other ML-based DOA estimation methods.
2014-01-01
This research is devoted to analyzing the dynamic loads generated in the glove machine at reciprocating motion of knitting and intermediate carriages. Proposed is a method for determining the maximum dynamic loads in the glove machine carriages’ drive. It is noted that the dynamic loads reduction can be achieved by equipping the drive with energy accumulation and compensation units, in which quality it is expedient to use the cylindrical compression springs. The obtained dependence allows to ...
Remington, Anna M.; Swettenham, John G.; Lavie, Nilli
2012-01-01
Autism spectrum disorder (ASD) research portrays a mixed picture of attentional abilities with demonstrations of enhancements (e.g., superior visual search) and deficits (e.g., higher distractibility). Here we test a potential resolution derived from the Load Theory of Attention (e.g., Lavie, 2005). In Load Theory, distractor processing depends on the perceptual load of the task and as such can only be eliminated under high load that engages full capacity. We hypothesize that ASD involves enh...
Maximum Multiflow in Wireless Network Coding
Zhou, Jin-Yi; Jiang, Yong; Zheng, Hai-Tao
2012-01-01
In a multihop wireless network, wireless interference is crucial to the maximum multiflow (MMF) problem, which studies the maximum throughput between multiple pairs of sources and sinks. In this paper, we observe that network coding could help to decrease the impacts of wireless interference, and propose a framework to study the MMF problem for multihop wireless networks with network coding. Firstly, a network model is set up to describe the new conflict relations modified by network coding. Then, we formulate a linear programming problem to compute the maximum throughput and show its superiority over one in networks without coding. Finally, the MMF problem in wireless network coding is shown to be NP-hard and a polynomial approximation algorithm is proposed.
Maximum Power Point Tracking Based on Sliding Mode Control
Nimrod Vázquez
2015-01-01
Full Text Available Solar panels, which have become a good choice, are used to generate and supply electricity in commercial and residential applications. This generated power starts with the solar cells, which have a complex relationship between solar irradiation, temperature, and output power. For this reason a tracking of the maximum power point is required. Traditionally, this has been made by considering just current and voltage conditions at the photovoltaic panel; however, temperature also influences the process. In this paper the voltage, current, and temperature in the PV system are considered to be a part of a sliding surface for the proposed maximum power point tracking; this means a sliding mode controller is applied. Obtained results gave a good dynamic response, as a difference from traditional schemes, which are only based on computational algorithms. A traditional algorithm based on MPPT was added in order to assure a low steady state error.
Maximum information entropy: a foundation for ecological theory.
Harte, John; Newman, Erica A
2014-07-01
The maximum information entropy (MaxEnt) principle is a successful method of statistical inference that has recently been applied to ecology. Here, we show how MaxEnt can accurately predict patterns such as species-area relationships (SARs) and abundance distributions in macroecology and be a foundation for ecological theory. We discuss the conceptual foundation of the principle, why it often produces accurate predictions of probability distributions in science despite not incorporating explicit mechanisms, and how mismatches between predictions and data can shed light on driving mechanisms in ecology. We also review possible future extensions of the maximum entropy theory of ecology (METE), a potentially important foundation for future developments in ecological theory.
Maximum work extraction and implementation costs for nonequilibrium Maxwell's demons
Sandberg, Henrik; Delvenne, Jean-Charles; Newton, Nigel J.; Mitter, Sanjoy K.
2014-10-01
We determine the maximum amount of work extractable in finite time by a demon performing continuous measurements on a quadratic Hamiltonian system subjected to thermal fluctuations, in terms of the information extracted from the system. The maximum work demon is found to apply a high-gain continuous feedback involving a Kalman-Bucy estimate of the system state and operates in nonequilibrium. A simple and concrete electrical implementation of the feedback protocol is proposed, which allows for analytic expressions of the flows of energy, entropy, and information inside the demon. This let us show that any implementation of the demon must necessarily include an external power source, which we prove both from classical thermodynamics arguments and from a version of Landauer's memory erasure argument extended to nonequilibrium linear systems.
Space weather Preparing for the Maximum of the Solar Cycle
Shaltout, Mosalam
: Space Environments Group preparing for the maximum of the solar cycle 24 where the current plan envisage that the National second Earth Research satellite EgyptSat2 will be launched in 2012. For that, forecasting the solar activity at 2012 is very important. The plan depend on the long-term prediction by using 10.7cm of Ottawa data (1947-2008) and applying fast Fourier transform FFT on this time series. Also, Using the Artificial Intelligence to predict the maximum activity by Fuzzy modeling. Also, Short-term prediction for Coronal mass ejection CMEs by the artificial satellite STEREO observations, beside other satellites as SOHO, Hinde, SDO, Solar orbiter sentinels, Solar Probe in collaboration with Paris Observatory in Meudon, France.
Kenny, John
1995-01-01
Discusses the snow -load capacity of school roofs and how understanding this data aids in planning preventive measures and easing fear of roof collapse. Describes how to determine snow-load capacity, and explains the load-bearing behavior of flat versus sloped roofs. Collapse prevention measures are highlighted. (GR)
The Wiener maximum quadratic assignment problem
Cela, Eranda; Woeginger, Gerhard J
2011-01-01
We investigate a special case of the maximum quadratic assignment problem where one matrix is a product matrix and the other matrix is the distance matrix of a one-dimensional point set. We show that this special case, which we call the Wiener maximum quadratic assignment problem, is NP-hard in the ordinary sense and solvable in pseudo-polynomial time. Our approach also yields a polynomial time solution for the following problem from chemical graph theory: Find a tree that maximizes the Wiener index among all trees with a prescribed degree sequence. This settles an open problem from the literature.
Maximum confidence measurements via probabilistic quantum cloning
Zhang Wen-Hai; Yu Long-Bao; Cao Zhuo-Liang; Ye Liu
2013-01-01
Probabilistic quantum cloning (PQC) cannot copy a set of linearly dependent quantum states.In this paper,we show that if incorrect copies are allowed to be produced,linearly dependent quantum states may also be cloned by the PQC.By exploiting this kind of PQC to clone a special set of three linearly dependent quantum states,we derive the upper bound of the maximum confidence measure of a set.An explicit transformation of the maximum confidence measure is presented.
Maximum floodflows in the conterminous United States
Crippen, John R.; Bue, Conrad D.
1977-01-01
Peak floodflows from thousands of observation sites within the conterminous United States were studied to provide a guide for estimating potential maximum floodflows. Data were selected from 883 sites with drainage areas of less than 10,000 square miles (25,900 square kilometers) and were grouped into regional sets. Outstanding floods for each region were plotted on graphs, and envelope curves were computed that offer reasonable limits for estimates of maximum floods. The curves indicate that floods may occur that are two to three times greater than those known for most streams.
Revealing the Maximum Strength in Nanotwinned Copper
Lu, L.; Chen, X.; Huang, Xiaoxu
2009-01-01
The strength of polycrystalline materials increases with decreasing grain size. Below a critical size, smaller grains might lead to softening, as suggested by atomistic simulations. The strongest size should arise at a transition in deformation mechanism from lattice dislocation activities to grain...... boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced...
The Maximum Resource Bin Packing Problem
Boyar, J.; Epstein, L.; Favrholdt, L.M.
2006-01-01
Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find...
Maximum entropy analysis of EGRET data
Pohl, M.; Strong, A.W.
1997-01-01
EGRET data are usually analysed on the basis of the Maximum-Likelihood method \\cite{ma96} in a search for point sources in excess to a model for the background radiation (e.g. \\cite{hu97}). This method depends strongly on the quality of the background model, and thus may have high systematic unce...... uncertainties in region of strong and uncertain background like the Galactic Center region. Here we show images of such regions obtained by the quantified Maximum-Entropy method. We also discuss a possible further use of MEM in the analysis of problematic regions of the sky....
Revealing the Maximum Strength in Nanotwinned Copper
Lu, L.; Chen, X.; Huang, Xiaoxu
2009-01-01
The strength of polycrystalline materials increases with decreasing grain size. Below a critical size, smaller grains might lead to softening, as suggested by atomistic simulations. The strongest size should arise at a transition in deformation mechanism from lattice dislocation activities to grain...... boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced...
Maximum phytoplankton concentrations in the sea
Jackson, G.A.; Kiørboe, Thomas
2008-01-01
A simplification of plankton dynamics using coagulation theory provides predictions of the maximum algal concentration sustainable in aquatic systems. These predictions have previously been tested successfully against results from iron fertilization experiments. We extend the test to data collected...... in the North Atlantic as part of the Bermuda Atlantic Time Series program as well as data collected off Southern California as part of the Southern California Bight Study program. The observed maximum particulate organic carbon and volumetric particle concentrations are consistent with the predictions...
Two-way Shape Memory Effect of NiTi under Compressive Loading Cycles
Yoo, Young Ik; Lee, Jung Ju
In this study, the two-way shape memory effect (TWSME) of a Ni-54.5 at.% Ti alloy was investigated experimentally to develop a NiTi linear actuator. The two-way shape memory effect was induced through a compressive shape memory cycle composed of four steps: (1) loading to maximum deformation; (2) unloading; (3) heating; (4) and cooling. Six types of specimens (one solid cylindrical and five tubular) were used to obtain the twoway shape memory strain and two-way recovery stress and to evaluate the actuating capacity. The two-way actuating strain showed a convergent tendency after several training cycles for the same maximum deformation. A maximum value of the two-way strain was obtained for 7% of maximum deformation, independently of the geometry of the tubular specimens. The two-way strains obtained by the shape memory cycles and two-way recovery stress linearly increase as a function of the maximum deformation and the two-way strain, respectively, and the geometry of specimen affects the two-way recovery stress. Although the results show that sufficient recovery stress can be generated by either the two-way shape memory process or by the one-way shape memory process, the two-way shape memory process can be applied more conveniently to actuating applications.
Mathematical Model and Artificial Intelligent Techniques Applied to a Milk Industry through DSM
Babu, P. Ravi; Divya, V. P. Sree
2011-08-01
The resources for electrical energy are depleting and hence the gap between the supply and the demand is continuously increasing. Under such circumstances, the option left is optimal utilization of available energy resources. The main objective of this chapter is to discuss about the Peak load management and overcome the problems associated with it in processing industries such as Milk industry with the help of DSM techniques. The chapter presents a generalized mathematical model for minimizing the total operating cost of the industry subject to the constraints. The work presented in this chapter also deals with the results of application of Neural Network, Fuzzy Logic and Demand Side Management (DSM) techniques applied to a medium scale milk industrial consumer in India to achieve the improvement in load factor, reduction in Maximum Demand (MD) and also the consumer gets saving in the energy bill.
Numerical Simulation of Rock Fragmentation under the Impact Load of Water Jet
Jiang Hongxiang
2014-01-01
Full Text Available To investigate the rock fragmentation and its influence factors under the impact load of water jet, a numerical method which coupled finite element method (FEM with smoothed particle hydrodynamics (SPH was adopted to simulate the rock fragmentation process by water jet. Linear and shock equations of state were applied to describe the dynamic characteristics of rock and water, respectively, while the maximum principal stress criterion was used for the rock failure detection. The dynamic stresses at the selected element containing points in rock are computed as a function of time under the impact load of water jet. The influences of the factors of boundary condition, impact velocity, confining pressure, and structure plane on rock dynamic fragmentation are discussed.
An estimation of load characteristics of an ultrasonic motor by measuring transient responses.
Nakamura, K; Kurosawa, M; Kurebayashi, H; Ueha, S
1991-01-01
To measure the characteristics of ultrasonic motors, such as the maximum torque, torque-speed relationship and the frictional coefficient at the contact surface, a method in which the torque is calculated from the transient responses is proposed. The rise curve that is the transitional change in the rotor speed soon after turning on the motor gives the load characteristics, while the fall curve that is the decay of the rotor speed after turning off the motor yields the frictional coefficient of the contact surface. This method requires only a short time (the transient time of the motor) to complete the measurement. The relations between the transient responses, the load characteristics and the frictional force are analyzed, and the method is applied to a hybrid transducer type rotary motor and a traveling wave type linear motor.
Comprehensive Review on Divisible Load Theory: Concepts, Strategies, and Approaches
Shamsollah Ghanbari
2014-01-01
Full Text Available There is extensive literature concerning the divisible load theory. The divisible load theory is mainly applied for scheduling in the area of distributed computing. It is based on the fact that the load can be divided into some arbitrarily independent parts, in which each part can be processed independently by a processor. This paper reviews the literature concerning the divisible load theory, while focusing on the details of the basic concepts, approaches, strategies, typologies, and open problems.
Ji-Su Kim
2015-04-01
Full Text Available This paper proposes strain-based acceptance criteria for assessing plastic instability of the safety class 1 nuclear components made of ferritic steel during level D service loads. The strain-based criteria were proposed with two approaches: (1 a section average approach and (2 a critical location approach. Both approaches were based on the damage initiation point corresponding to the maximum load-carrying capability point instead of the fracture point via tensile tests and finite element analysis (FEA for the notched specimen under uni-axial tensile loading. The two proposed criteria were reviewed from the viewpoint of design practice and philosophy to select a more appropriate criterion. As a result of the review, it was found that the section average approach is more appropriate than the critical location approach from the viewpoint of design practice and philosophy. Finally, the criterion based on the section average approach was applied to a simplified reactor pressure vessel (RPV outlet nozzle subject to SSE loads. The application shows that the strain-based acceptance criteria can consider cumulative damages caused by the sequential loads unlike the stress-based acceptance criteria and can reduce the overconservatism of the stress-based acceptance criteria, which often occurs for level D service loads.
R Wave Extraction Based on the Maximum First Derivative plus the Maximum Value of the Double Search
Wen-po Yao; Wen-li Yao; Min Wu; Tie-bing Liu
2016-01-01
R-wave detection is the main approach for heart rate variability analysis and clinical application based on R-R interval. The maximum ifrst derivative plus the maximum value of the double search algorithm is applied on electrocardiogram (ECG) of MIH-BIT Arrhythmia Database to extract R wave. Through the study of algorithm's characteristics and R-wave detection method, data segmentation method is modified to improve the detection accuracy. After segmentation modification, average accuracy rate of 6 sets of short ECG data increase from 82.51% to 93.70%, and the average accuracy rate of 11 groups long-range data is 96.61%. Test results prove that the algorithm and segmentation method can accurately locate R wave and have good effectiveness and versatility, but may exist some undetected problems due to algorithm implementation.
Spatial electric load forecasting
Willis, H Lee
2002-01-01
Spatial Electric Load Forecasting Consumer Demand for Power and ReliabilityCoincidence and Load BehaviorLoad Curve and End-Use ModelingWeather and Electric LoadWeather Design Criteria and Forecast NormalizationSpatial Load Growth BehaviorSpatial Forecast Accuracy and Error MeasuresTrending MethodsSimulation Method: Basic ConceptsA Detailed Look at the Simulation MethodBasics of Computerized SimulationAnalytical Building Blocks for Spatial SimulationAdvanced Elements of Computerized SimulationHybrid Trending-Simulation MethodsAdvanced
Andersen, Casper Welzel; Bremholm, Martin; Vennestrøm, Peter Nicolai Ravnborg; Blichfeld, Anders Bank; Lundegaard, Lars Fahl; Iversen, Bo Brummerstedt
2014-11-01
Accurate structural models of reaction centres in zeolite catalysts are a prerequisite for mechanistic studies and further improvements to the catalytic performance. The Rietveld/maximum entropy method is applied to synchrotron powder X-ray diffraction data on fully dehydrated CHA-type zeolites with and without loading of catalytically active Cu(2+) for the selective catalytic reduction of NO x with NH3. The method identifies the known Cu(2+) sites in the six-membered ring and a not previously observed site in the eight-membered ring. The sum of the refined Cu occupancies for these two sites matches the chemical analysis and thus all the Cu is accounted for. It is furthermore shown that approximately 80% of the Cu(2+) is located in the new 8-ring site for an industrially relevant CHA zeolite with Si/Al = 15.5 and Cu/Al = 0.45. Density functional theory calculations are used to corroborate the positions and identity of the two Cu sites, leading to the most complete structural description of dehydrated silicoaluminate CHA loaded with catalytically active Cu(2+) cations.
On maximum cycle packings in polyhedral graphs
Peter Recht
2014-04-01
Full Text Available This paper addresses upper and lower bounds for the cardinality of a maximum vertex-/edge-disjoint cycle packing in a polyhedral graph G. Bounds on the cardinality of such packings are provided, that depend on the size, the order or the number of faces of G, respectively. Polyhedral graphs are constructed, that attain these bounds.
Hard graphs for the maximum clique problem
Hoede, Cornelis
1988-01-01
The maximum clique problem is one of the NP-complete problems. There are graphs for which a reduction technique exists that transforms the problem for these graphs into one for graphs with specific properties in polynomial time. The resulting graphs do not grow exponentially in order and number. Gra
Weak Scale From the Maximum Entropy Principle
Hamada, Yuta; Kawana, Kiyoharu
2015-01-01
The theory of multiverse and wormholes suggests that the parameters of the Standard Model are fixed in such a way that the radiation of the $S^{3}$ universe at the final stage $S_{rad}$ becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the Standard Model, we can check whether $S_{rad}$ actually becomes maximum at the observed values. In this paper, we regard $S_{rad}$ at the final stage as a function of the weak scale ( the Higgs expectation value ) $v_{h}$, and show that it becomes maximum around $v_{h}={\\cal{O}}(300\\text{GeV})$ when the dimensionless couplings in the Standard Model, that is, the Higgs self coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by \\begin{equation} v_{h}\\sim\\frac{T_{BBN}^{2}}{M_{pl}y_{e}^{5}},\
Weak scale from the maximum entropy principle
Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu
2015-03-01
The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.
Global characterization of the Holocene Thermal Maximum
Renssen, H.; Seppä, H.; Crosta, X.; Goosse, H.; Roche, D.M.V.A.P.
2012-01-01
We analyze the global variations in the timing and magnitude of the Holocene Thermal Maximum (HTM) and their dependence on various forcings in transient simulations covering the last 9000 years (9 ka), performed with a global atmosphere-ocean-vegetation model. In these experiments, we consider the i
Instance Optimality of the Adaptive Maximum Strategy
L. Diening; C. Kreuzer; R. Stevenson
2016-01-01
In this paper, we prove that the standard adaptive finite element method with a (modified) maximum marking strategy is instance optimal for the total error, being the square root of the squared energy error plus the squared oscillation. This result will be derived in the model setting of Poisson’s e
Maximum phonation time: variability and reliability.
Speyer, Renée; Bogaardt, Hans C A; Passos, Valéria Lima; Roodenburg, Nel P H D; Zumach, Anne; Heijnen, Mariëlle A M; Baijens, Laura W J; Fleskens, Stijn J H M; Brunings, Jan W
2010-05-01
The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia versus a group of healthy control subjects matched by age and gender. Over a period of maximally 6 weeks, three video recordings were made of five subjects' maximum phonation time trials. A panel of five experts were responsible for all measurements, including a repeated measurement of the subjects' first recordings. Patients showed significantly shorter maximum phonation times compared with healthy controls (on average, 6.6 seconds shorter). The averaged interclass correlation coefficient (ICC) over all raters per trial for the first day was 0.998. The averaged reliability coefficient per rater and per trial for repeated measurements of the first day's data was 0.997, indicating high intrarater reliability. The mean reliability coefficient per day for one trial was 0.939. When using five trials, the reliability increased to 0.987. The reliability over five trials for a single day was 0.836; for 2 days, 0.911; and for 3 days, 0.935. To conclude, the maximum phonation time has proven to be a highly reliable measure in voice assessment. A single rater is sufficient to provide highly reliable measurements.
Maximum Phonation Time: Variability and Reliability
R. Speyer; H.C.A. Bogaardt; V.L. Passos; N.P.H.D. Roodenburg; A. Zumach; M.A.M. Heijnen; L.W.J. Baijens; S.J.H.M. Fleskens; J.W. Brunings
2010-01-01
The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia v
Maximum likelihood estimation of fractionally cointegrated systems
Lasak, Katarzyna
In this paper we consider a fractionally cointegrated error correction model and investigate asymptotic properties of the maximum likelihood (ML) estimators of the matrix of the cointe- gration relations, the degree of fractional cointegration, the matrix of the speed of adjustment...
Maximum likelihood estimation for integrated diffusion processes
Baltazar-Larios, Fernando; Sørensen, Michael
EM-algorithm to obtain maximum likelihood estimates of the parameters in the diffusion model. As part of the algorithm, we use a recent simple method for approximate simulation of diffusion bridges. In simulation studies for the Ornstein-Uhlenbeck process and the CIR process the proposed method works...
Colombo, Vera; Correro, Maria Rita; Riener, Robert; Weber, Franz E; Gallo, Luigi M
2011-07-01
Osteoarthritis is a chronic degenerative disease affecting body joints. Abnormal mechanical loading could be an initiating factor of cartilage damage, by influencing chondrocytes activity. To date, devices performing mechanical studies of viable tissues are mostly uniaxial. In this work, we developed and validated a multi-axial device for static and dynamic mechanical testing of viable soft tissues. The system, named RPETS, is composed of a motor driven indenter, moving vertically and horizontally along the bottom of a tank containing tissue samples and it can apply combined compression, sliding, and rolling on viable samples. Validation studies were performed with standard rubber and bovine nasal cartilage tissue. Static tests demonstrated that the system is comparable to existing uniaxial devices, with a maximum force control error smaller than 0.5N and a positioning resolution of 5 μm. Dynamic tests performed with different motion profiles showed that the system can exert a load of 100N with a maximum velocity of 100mm/s maintaining the force control error within 10% of the desired value. Sinusoidal motion frequency can vary between 0.05 and 0.5Hz. In practical tests, viability staining of dynamically loaded cartilage slices showed extents of cell death to depend on the indenter velocity. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.
Tests of maximum oxygen intake. A critical review.
Shephard, R J
1984-01-01
The determinants of endurance effort vary, depending upon the extent of the muscle mass that is activated. Large muscle work, such as treadmill running, is halted by impending circulatory failure; lack of venous return may compound the basic problem of an excessive cardiac work-load. If the task calls for use of a smaller muscle mass, there is ultimately difficulty in perfusing the active muscles, and glycolysis is halted by an accumulation of acid metabolites. Simple field tests of endurance, such as Cooper's 12-minute run and the Canadian Home Fitness Test, have some value in the rapid screening of large populations, but like other submaximal tests of human performance they lack the precision needed to advise the individual. The directly measured maximum oxygen intake (VO2 max) varies with the type of exercise. The highest values are obtained during uphill treadmill running, but well trained athletes often approach these values during performance of sport-specific tasks. Limitations of methodology and wide interindividual variations of constitutional potential limit the interpretation of maximum oxygen intake data in terms of personal fitness, exercise prescription and the monitoring of training responses. The main practical value of VO2 max measurement is in the functional assessment of patients with cardiorespiratory disease, since changes are then large relative to the precision of the test.
Radiation engineering of optical antennas for maximum field enhancement.
Seok, Tae Joon; Jamshidi, Arash; Kim, Myungki; Dhuey, Scott; Lakhani, Amit; Choo, Hyuck; Schuck, Peter James; Cabrini, Stefano; Schwartzberg, Adam M; Bokor, Jeffrey; Yablonovitch, Eli; Wu, Ming C
2011-07-13
Optical antennas have generated much interest in recent years due to their ability to focus optical energy beyond the diffraction limit, benefiting a broad range of applications such as sensitive photodetection, magnetic storage, and surface-enhanced Raman spectroscopy. To achieve the maximum field enhancement for an optical antenna, parameters such as the antenna dimensions, loading conditions, and coupling efficiency have been previously studied. Here, we present a framework, based on coupled-mode theory, to achieve maximum field enhancement in optical antennas through optimization of optical antennas' radiation characteristics. We demonstrate that the optimum condition is achieved when the radiation quality factor (Q(rad)) of optical antennas is matched to their absorption quality factor (Q(abs)). We achieve this condition experimentally by fabricating the optical antennas on a dielectric (SiO(2)) coated ground plane (metal substrate) and controlling the antenna radiation through optimizing the dielectric thickness. The dielectric thickness at which the matching condition occurs is approximately half of the quarter-wavelength thickness, typically used to achieve constructive interference, and leads to ∼20% higher field enhancement relative to a quarter-wavelength thick dielectric layer.
Application of Maximum Entropy Distribution to the Statistical Properties of Wave Groups
无
2007-01-01
The new distributions of the statistics of wave groups based on the maximum entropy principle are presented. The maximum entropy distributions appear to be superior to conventional distributions when applied to a limited amount of information. Its applications to the wave group properties show the effectiveness of the maximum entropy distribution. FFT filtering method is employed to obtain the wave envelope fast and efficiently. Comparisons of both the maximum entropy distribution and the distribution of Longuet-Higgins (1984) with the laboratory wind-wave data show that the former gives a better fit.
Hoffmeyer, Preben; Sørensen, John Dalsgaard
2007-01-01
were formed. Four groups were subjected to short-term strength tests, and four groups were subjected to long-term tests. Creep and time to failure were moni-tored. Time to failure as a function of stress level was established and the reliability of stress level assessment was discussed. A significant...... mechanosorptive effect was demonstrated both in terms of increased creep and shortening of time to failure. The test results were employed for the calibration of four existing duration of load models. The effect of long-term loading was expressed as the stress level SL50 to cause failure after 50 years of loading...... and of the short-term and long-term strengths. For permanent and imposed library loads, reliability-based estimation of the load duration factor gave almost the same results as direct, deterministic calibration. Keywords: Creep, damage models, duration of load, equal rank assumption, load duration factor, matched...
A simple approach for maximum heat recovery calculations
Jezowski, J. (Wroclaw Technical Univ. (PL). Inst. of Chemical Engineering and Heating Equipment); Friedler, F. (Hungarian Academy of Sciences, Egyetem (HU). Research Inst. for Technical Chmeistry)
1992-04-01
This paper addresses the problem of calculating the maximum heat energy recovery for a given set of process streams. Simple, straightforward algorithms of calculations are presented that account for tasks with multiple utilities, forbidden matches and nonpoint utilities. A new way of applying the so-called dual-stream approach to reduce utility usage for tasks with forbidden matches is also given in this paper. The calculation methods do not require computer programs and mathematical programming application. They give the user a proper insight into a problem to understand heat integration as well as to recognize options and traps in heat exchanger network synthesis. (author).
Improving predictability of time series using maximum entropy methods
Chliamovitch, G.; Dupuis, A.; Golub, A.; Chopard, B.
2015-04-01
We discuss how maximum entropy methods may be applied to the reconstruction of Markov processes underlying empirical time series and compare this approach to usual frequency sampling. It is shown that, in low dimension, there exists a subset of the space of stochastic matrices for which the MaxEnt method is more efficient than sampling, in the sense that shorter historical samples have to be considered to reach the same accuracy. Considering short samples is of particular interest when modelling smoothly non-stationary processes, which provides, under some conditions, a powerful forecasting tool. The method is illustrated for a discretized empirical series of exchange rates.
Approximated maximum likelihood estimation in multifractal random walks
Løvsletten, Ola
2011-01-01
We present an approximated maximum likelihood method for the multifractal random walk processes of [E. Bacry et al., Phys. Rev. E 64, 026103 (2001)]. The likelihood is computed using a Laplace approximation and a truncation in the dependency structure for the latent volatility. The procedure is implemented as a package in the R computer language. Its performance is tested on synthetic data and compared to an inference approach based on the generalized method of moments. The method is applied to estimate parameters for various financial stock indices.
Sharifnezhad, Ali; Marzilger, Robert; Arampatzis, Adamantios
2014-08-01
The present study investigated the longitudinal growth of the vastus lateralis muscle using four eccentric exercise protocols with different mechanical stimuli by modifying the load magnitude, lengthening velocity and muscle length at which the load was applied. Thirty-one participants voluntarily participated in this study in two experimental and one control group. The first experimental group (N=10) exercised the knee extensors of one leg at 65% (low load magnitude) of the maximum isometric voluntary contraction (MVC) and the second leg at 100% MVC (high load magnitude) with 90 deg s(-1) angular velocity, from 25 to 100 deg knee angle. The second experimental group (N=10) exercised one leg at 100% MVC, 90 deg s(-1), from 25 to 65 deg knee angle (short muscle length). The other leg was exercised at 100% MVC, 240 deg s(-1) angular velocity (high muscle lengthening velocity) from 25 to 100 deg. In the pre- and post-intervention measurements, we examined the fascicle length of the vastus lateralis at rest and the moment-angle relationship of the knee extensors. After 10 weeks of intervention, we found a significant increase (~14%) of vastus lateralis fascicle length compared with the control group, yet only in the leg that was exercised with high lengthening velocity. The findings provide evidence that not every eccentric loading causes an increase in fascicle length and that the lengthening velocity of the fascicles during the eccentric loading, particularly in the phase where the knee joint moment decreases (i.e. deactivation of the muscle), seems to be an important factor for longitudinal muscle growth. © 2014. Published by The Company of Biologists Ltd.
Drinking Water Maximum Contaminant Levels (MCLs)
U.S. Environmental Protection Agency — National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards...
N.A. Noukeu
2016-12-01
Full Text Available In this study, effluents from 11 food processing industries from various sectors were characterized through analysis of physical and chemical parameters. In general, effluents pHs are between 4.07 and 7.63. Lead (Pb2+ and cadmium (Cd+ concentrations range from 0.083 to 1.025 mg/l and 0.052–0.158 mg/l respectively. The biodegradability of the effluent is very low. The principal component analysis (PCA grouped industries according to their organic matter levels; thus, stillage, livestock, molasses and sugar refinery effluents show some similarities, as well as confectionery, oil mill, dairy and brewery effluents. Forms of nitrogen measured show low levels of nitrites (NO2−, high levels of nitrates (NO3−, ammonium (NH4+ and Kjeldahl nitrogen (TKN. Among these effluents, a treatment trial with Eichhornia crassipes and Panicum maximum was applied to stillage effluent from Fermencam distillery. The results show that Panicum maximum and Eichhornia crassipes reduce pollutant loads of Fermencam's wastewater.
Lloyd, R; Parr, B; Davies, S; Partridge, T; Cooke, C
2010-07-01
The aim is to quantify the physiological cost of head-load carriage and to examine the 'free ride' hypothesis for head-load carriage in groups of women differing in their experience of head-loading. Twenty-four Xhosa women [13 experienced head-loaders (EXP), 11 with no experience of head-loading (NON)] attempted to carry loads of up to 70% of body mass on both their heads and backs whilst walking on a treadmill at a self-selected walking speed. Expired air was collected throughout. In a second study nine women, members of the British Territorial Army, carried similar loads, again at a self-selected speed. Maximum load carried was greater for the back than the head (54.7 +/- 15.1 vs. 40.8 +/- 13.2% BM, P head-loading required a greater oxygen rate than back-loading (10.1 +/- 2.6 vs. 8.8 +/- 2.3 ml kg bodymass(-1) min(-1), P = 0.043, for loads 10-25% BM) regardless of previous head-loading experience (P = 0.333). Percentage changes in oxygen consumption associated with head-loading were greater than the proportional load added in both studies but were smaller than the added load for the lighter loads carried on the back in study 1. All other physiological variables were consistent with changes in oxygen consumption. The data provides no support for the 'free ride' hypothesis for head-loading although there is some evidence of energy saving mechanisms for back-loading at low speed/load combinations. Investigating the large individual variation in response may help in identifying combinations of factors that contribute to improved economy.
Wind turbine blade testing under combined loading
Roczek-Sieradzan, Agnieszka; Nielsen, Magda; Branner, Kim;
2011-01-01
The paper presents full-scale blade tests under a combined flap- and edgewise loading. The main aim of this paper is to present the results from testing a wind turbine blade under such conditions and to study the structural behavior of the blade subjected to combined loading. A loading method using...... anchor plates was applied, allowing transverse shear distortion. The global and local deformation of the blade as well as the reproducibility of the test was studied and the results from the investigations are presented....
Synthesis of polyoxometalate-loaded epoxy composites
Anderson, Benjamin J
2014-10-07
The synthesis of a polyoxometalate-loaded epoxy uses a one-step cure by applying an external stimulus to release the acid from the polyoxometalate and thereby catalyze the cure reaction of the epoxy resin. Such polyoxometalate-loaded epoxy composites afford the cured epoxy unique properties imparted by the intrinsic properties of the polyoxometalate. For example, polyoxometalate-loaded epoxy composites can be used as corrosion resistant epoxy coatings, for encapsulation of electronics with improved dielectric properties, and for structural applications with improved mechanical properties.
Koponen, P. [VTT Energy, Espoo (Finland)
1998-08-01
Electricity cannot be stored in large quantities. That is why the electricity supply and consumption are always almost equal in large power supply systems. If this balance were disturbed beyond stability, the system or a part of it would collapse until a new stable equilibrium is reached. The balance between supply and consumption is mainly maintained by controlling the power production, but also the electricity consumption or, in other words, the load is controlled. Controlling the load of the power supply system is important, if easily controllable power production capacity is limited. Temporary shortage of capacity causes high peaks in the energy price in the electricity market. Load control either reduces the electricity consumption during peak consumption and peak price or moves electricity consumption to some other time. The project Optimisation of Load Control is a part of the EDISON research program for distribution automation. The following areas were studied: Optimization of space heating and ventilation, when electricity price is time variable, load control model in power purchase optimization, optimization of direct load control sequences, interaction between load control optimization and power purchase optimization, literature on load control, optimization methods and field tests and response models of direct load control and the effects of the electricity market deregulation on load control. An overview of the main results is given in this chapter
Predicting physiological capacity of human load carriage - a review.
Drain, Jace; Billing, Daniel; Neesham-Smith, Daniel; Aisbett, Brad
2016-01-01
This review article aims to evaluate a proposed maximum acceptable work duration model for load carriage tasks. It is contended that this concept has particular relevance to physically demanding occupations such as military and firefighting. Personnel in these occupations are often required to perform very physically demanding tasks, over varying time periods, often involving load carriage. Previous research has investigated concepts related to physiological workload limits in occupational settings (e.g. industrial). Evidence suggests however, that existing (unloaded) workload guidelines are not appropriate for load carriage tasks. The utility of this model warrants further work to enable prediction of load carriage durations across a range of functional workloads for physically demanding occupations. If the maximum duration for which personnel can physiologically sustain a load carriage task could be accurately predicted, commanders and supervisors could better plan for and manage tasks to ensure operational imperatives were met whilst minimising health risks for their workers.
Numerical prediction of slamming loads
Seng, Sopheak; Jensen, Jørgen J; Pedersen, Preben T
2012-01-01
. The pressure distribution as well as the total force is then determined by integration over a pseudo-three-dimensional presentation of the hull geometry.In this paper the evaluation of the slamming load is taken one step further by performing direct three-dimensional, fully non-linear numerical calculations...... in a realistic wave environment.Both the global and the local slamming loads are assessed numerically using a finite-volume formulation with the free surface captured by a volume-of-fluid technique. This numerical procedure is justified by comprehensive validation studies where numerically evaluated slamming...... pressures are compared with experimentally measured results.To obtain an insight into the three-dimensional flow effects the next step is to apply the validated numerical procedure to evaluate and compare the accuracy and performance of the traditionally used two-dimensional formulations by a comparison...
Model Selection Through Sparse Maximum Likelihood Estimation
Banerjee, Onureena; D'Aspremont, Alexandre
2007-01-01
We consider the problem of estimating the parameters of a Gaussian or binary distribution in such a way that the resulting undirected graphical model is sparse. Our approach is to solve a maximum likelihood problem with an added l_1-norm penalty term. The problem as formulated is convex but the memory requirements and complexity of existing interior point methods are prohibitive for problems with more than tens of nodes. We present two new algorithms for solving problems with at least a thousand nodes in the Gaussian case. Our first algorithm uses block coordinate descent, and can be interpreted as recursive l_1-norm penalized regression. Our second algorithm, based on Nesterov's first order method, yields a complexity estimate with a better dependence on problem size than existing interior point methods. Using a log determinant relaxation of the log partition function (Wainwright & Jordan (2006)), we show that these same algorithms can be used to solve an approximate sparse maximum likelihood problem for...
Maximum Variance Hashing via Column Generation
Lei Luo
2013-01-01
item search. Recently, a number of data-dependent methods have been developed, reflecting the great potential of learning for hashing. Inspired by the classic nonlinear dimensionality reduction algorithm—maximum variance unfolding, we propose a novel unsupervised hashing method, named maximum variance hashing, in this work. The idea is to maximize the total variance of the hash codes while preserving the local structure of the training data. To solve the derived optimization problem, we propose a column generation algorithm, which directly learns the binary-valued hash functions. We then extend it using anchor graphs to reduce the computational cost. Experiments on large-scale image datasets demonstrate that the proposed method outperforms state-of-the-art hashing methods in many cases.
The Maximum Resource Bin Packing Problem
Boyar, J.; Epstein, L.; Favrholdt, L.M.
2006-01-01
algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find......Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... the competitive ratio of various natural algorithms. We study the general versions of the problems as well as the parameterized versions where there is an upper bound of on the item sizes, for some integer k....
Regions of constrained maximum likelihood parameter identifiability
Lee, C.-H.; Herget, C. J.
1975-01-01
This paper considers the parameter identification problem of general discrete-time, nonlinear, multiple-input/multiple-output dynamic systems with Gaussian-white distributed measurement errors. Knowledge of the system parameterization is assumed to be known. Regions of constrained maximum likelihood (CML) parameter identifiability are established. A computation procedure employing interval arithmetic is proposed for finding explicit regions of parameter identifiability for the case of linear systems. It is shown that if the vector of true parameters is locally CML identifiable, then with probability one, the vector of true parameters is a unique maximal point of the maximum likelihood function in the region of parameter identifiability and the CML estimation sequence will converge to the true parameters.
A Maximum Radius for Habitable Planets.
Alibert, Yann
2015-09-01
We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.
A stochastic maximum principle via Malliavin calculus
Øksendal, Bernt; Zhou, Xun Yu; Meyer-Brandis, Thilo
2008-01-01
This paper considers a controlled It\\^o-L\\'evy process where the information available to the controller is possibly less than the overall information. All the system coefficients and the objective performance functional are allowed to be random, possibly non-Markovian. Malliavin calculus is employed to derive a maximum principle for the optimal control of such a system where the adjoint process is explicitly expressed.
Tissue radiation response with maximum Tsallis entropy.
Sotolongo-Grau, O; Rodríguez-Pérez, D; Antoranz, J C; Sotolongo-Costa, Oscar
2010-10-08
The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature.
Maximum Estrada Index of Bicyclic Graphs
Wang, Long; Wang, Yi
2012-01-01
Let $G$ be a simple graph of order $n$, let $\\lambda_1(G),\\lambda_2(G),...,\\lambda_n(G)$ be the eigenvalues of the adjacency matrix of $G$. The Esrada index of $G$ is defined as $EE(G)=\\sum_{i=1}^{n}e^{\\lambda_i(G)}$. In this paper we determine the unique graph with maximum Estrada index among bicyclic graphs with fixed order.
Maximum privacy without coherence, zero-error
Leung, Debbie; Yu, Nengkun
2016-09-01
We study the possible difference between the quantum and the private capacities of a quantum channel in the zero-error setting. For a family of channels introduced by Leung et al. [Phys. Rev. Lett. 113, 030512 (2014)], we demonstrate an extreme difference: the zero-error quantum capacity is zero, whereas the zero-error private capacity is maximum given the quantum output dimension.
Automatic maximum entropy spectral reconstruction in NMR.
Mobli, Mehdi; Maciejewski, Mark W; Gryk, Michael R; Hoch, Jeffrey C
2007-10-01
Developments in superconducting magnets, cryogenic probes, isotope labeling strategies, and sophisticated pulse sequences together have enabled the application, in principle, of high-resolution NMR spectroscopy to biomolecular systems approaching 1 megadalton. In practice, however, conventional approaches to NMR that utilize the fast Fourier transform, which require data collected at uniform time intervals, result in prohibitively lengthy data collection times in order to achieve the full resolution afforded by high field magnets. A variety of approaches that involve nonuniform sampling have been proposed, each utilizing a non-Fourier method of spectrum analysis. A very general non-Fourier method that is capable of utilizing data collected using any of the proposed nonuniform sampling strategies is maximum entropy reconstruction. A limiting factor in the adoption of maximum entropy reconstruction in NMR has been the need to specify non-intuitive parameters. Here we describe a fully automated system for maximum entropy reconstruction that requires no user-specified parameters. A web-accessible script generator provides the user interface to the system.
Maximum entropy analysis of cosmic ray composition
Nosek, Dalibor; Vícha, Jakub; Trávníček, Petr; Nosková, Jana
2016-01-01
We focus on the primary composition of cosmic rays with the highest energies that cause extensive air showers in the Earth's atmosphere. A way of examining the two lowest order moments of the sample distribution of the depth of shower maximum is presented. The aim is to show that useful information about the composition of the primary beam can be inferred with limited knowledge we have about processes underlying these observations. In order to describe how the moments of the depth of shower maximum depend on the type of primary particles and their energies, we utilize a superposition model. Using the principle of maximum entropy, we are able to determine what trends in the primary composition are consistent with the input data, while relying on a limited amount of information from shower physics. Some capabilities and limitations of the proposed method are discussed. In order to achieve a realistic description of the primary mass composition, we pay special attention to the choice of the parameters of the sup...
A Maximum Resonant Set of Polyomino Graphs
Zhang Heping
2016-05-01
Full Text Available A polyomino graph P is a connected finite subgraph of the infinite plane grid such that each finite face is surrounded by a regular square of side length one and each edge belongs to at least one square. A dimer covering of P corresponds to a perfect matching. Different dimer coverings can interact via an alternating cycle (or square with respect to them. A set of disjoint squares of P is a resonant set if P has a perfect matching M so that each one of those squares is M-alternating. In this paper, we show that if K is a maximum resonant set of P, then P − K has a unique perfect matching. We further prove that the maximum forcing number of a polyomino graph is equal to the cardinality of a maximum resonant set. This confirms a conjecture of Xu et al. [26]. We also show that if K is a maximal alternating set of P, then P − K has a unique perfect matching.
Minimal Length, Friedmann Equations and Maximum Density
Awad, Adel
2014-01-01
Inspired by Jacobson's thermodynamic approach[gr-qc/9504004], Cai et al [hep-th/0501055,hep-th/0609128] have shown the emergence of Friedmann equations from the first law of thermodynamics. We extend Akbar--Cai derivation [hep-th/0609128] of Friedmann equations to accommodate a general entropy-area law. Studying the resulted Friedmann equations using a specific entropy-area law, which is motivated by the generalized uncertainty principle (GUP), reveals the existence of a maximum energy density closed to Planck density. Allowing for a general continuous pressure $p(\\rho,a)$ leads to bounded curvature invariants and a general nonsingular evolution. In this case, the maximum energy density is reached in a finite time and there is no cosmological evolution beyond this point which leaves the big bang singularity inaccessible from a spacetime prospective. The existence of maximum energy density and a general nonsingular evolution is independent of the equation of state and the spacial curvature $k$. As an example w...
Maximum saliency bias in binocular fusion
Lu, Yuhao; Stafford, Tom; Fox, Charles
2016-07-01
Subjective experience at any instant consists of a single ("unitary"), coherent interpretation of sense data rather than a "Bayesian blur" of alternatives. However, computation of Bayes-optimal actions has no role for unitary perception, instead being required to integrate over every possible action-percept pair to maximise expected utility. So what is the role of unitary coherent percepts, and how are they computed? Recent work provided objective evidence for non-Bayes-optimal, unitary coherent, perception and action in humans; and further suggested that the percept selected is not the maximum a posteriori percept but is instead affected by utility. The present study uses a binocular fusion task first to reproduce the same effect in a new domain, and second, to test multiple hypotheses about exactly how utility may affect the percept. After accounting for high experimental noise, it finds that both Bayes optimality (maximise expected utility) and the previously proposed maximum-utility hypothesis are outperformed in fitting the data by a modified maximum-salience hypothesis, using unsigned utility magnitudes in place of signed utilities in the bias function.
Maximum-biomass prediction of homofermentative Lactobacillus.
Cui, Shumao; Zhao, Jianxin; Liu, Xiaoming; Chen, Yong Q; Zhang, Hao; Chen, Wei
2016-07-01
Fed-batch and pH-controlled cultures have been widely used for industrial production of probiotics. The aim of this study was to systematically investigate the relationship between the maximum biomass of different homofermentative Lactobacillus and lactate accumulation, and to develop a prediction equation for the maximum biomass concentration in such cultures. The accumulation of the end products and the depletion of nutrients by various strains were evaluated. In addition, the minimum inhibitory concentrations (MICs) of acid anions for various strains at pH 7.0 were examined. The lactate concentration at the point of complete inhibition was not significantly different from the MIC of lactate for all of the strains, although the inhibition mechanism of lactate and acetate on Lactobacillus rhamnosus was different from the other strains which were inhibited by the osmotic pressure caused by acid anions at pH 7.0. When the lactate concentration accumulated to the MIC, the strains stopped growing. The maximum biomass was closely related to the biomass yield per unit of lactate produced (YX/P) and the MIC (C) of lactate for different homofermentative Lactobacillus. Based on the experimental data obtained using different homofermentative Lactobacillus, a prediction equation was established as follows: Xmax - X0 = (0.59 ± 0.02)·YX/P·C.
A methodology for multihazards load combinations of earthquake and heavy trucks for bridges.
Sun, Dezhang; Wang, Xu; Sun, Baitao
2014-01-01
Issues of load combinations of earthquakes and heavy trucks are important contents in multihazards bridge design. Current load resistance factor design (LRFD) specifications usually treat extreme hazards alone and have no probabilistic basis in extreme load combinations. Earthquake load and heavy truck load are considered as random processes with respective characteristics, and the maximum combined load is not the simple superimposition of their maximum loads. Traditional Ferry Borges-Castaneda model that considers load lasting duration and occurrence probability well describes random process converting to random variables and load combinations, but this model has strict constraint in time interval selection to obtain precise results. Turkstra's rule considers one load reaching its maximum value in bridge's service life combined with another load with its instantaneous value (or mean value), which looks more rational, but the results are generally unconservative. Therefore, a modified model is presented here considering both advantages of Ferry Borges-Castaneda's model and Turkstra's rule. The modified model is based on conditional probability, which can convert random process to random variables relatively easily and consider the nonmaximum factor in load combinations. Earthquake load and heavy truck load combinations are employed to illustrate the model. Finally, the results of a numerical simulation are used to verify the feasibility and rationality of the model.
A Methodology for Multihazards Load Combinations of Earthquake and Heavy Trucks for Bridges
Dezhang Sun
2014-01-01
Full Text Available Issues of load combinations of earthquakes and heavy trucks are important contents in multihazards bridge design. Current load resistance factor design (LRFD specifications usually treat extreme hazards alone and have no probabilistic basis in extreme load combinations. Earthquake load and heavy truck load are considered as random processes with respective characteristics, and the maximum combined load is not the simple superimposition of their maximum loads. Traditional Ferry Borges-Castaneda model that considers load lasting duration and occurrence probability well describes random process converting to random variables and load combinations, but this model has strict constraint in time interval selection to obtain precise results. Turkstra’s rule considers one load reaching its maximum value in bridge’s service life combined with another load with its instantaneous value (or mean value, which looks more rational, but the results are generally unconservative. Therefore, a modified model is presented here considering both advantages of Ferry Borges-Castaneda's model and Turkstra’s rule. The modified model is based on conditional probability, which can convert random process to random variables relatively easily and consider the nonmaximum factor in load combinations. Earthquake load and heavy truck load combinations are employed to illustrate the model. Finally, the results of a numerical simulation are used to verify the feasibility and rationality of the model.
A hybrid solar panel maximum power point search method that uses light and temperature sensors
Ostrowski, Mariusz
2016-04-01
Solar cells have low efficiency and non-linear characteristics. To increase the output power solar cells are connected in more complex structures. Solar panels consist of series of connected solar cells with a few bypass diodes, to avoid negative effects of partial shading conditions. Solar panels are connected to special device named the maximum power point tracker. This device adapt output power from solar panels to load requirements and have also build in a special algorithm to track the maximum power point of solar panels. Bypass diodes may cause appearance of local maxima on power-voltage curve when the panel surface is illuminated irregularly. In this case traditional maximum power point tracking algorithms can find only a local maximum power point. In this article the hybrid maximum power point search algorithm is presented. The main goal of the proposed method is a combination of two algorithms: a method that use temperature sensors to track maximum power point in partial shading conditions and a method that use illumination sensor to track maximum power point in equal illumination conditions. In comparison to another methods, the proposed algorithm uses correlation functions to determinate the relationship between values of illumination and temperature sensors and the corresponding values of current and voltage in maximum power point. In partial shading condition the algorithm calculates local maximum power points bases on the value of temperature and the correlation function and after that measures the value of power on each of calculated point choose those with have biggest value, and on its base run the perturb and observe search algorithm. In case of equal illumination algorithm calculate the maximum power point bases on the illumination value and the correlation function and on its base run the perturb and observe algorithm. In addition, the proposed method uses a special coefficient modification of correlation functions algorithm. This sub
Maximum Correntropy Unscented Kalman Filter for Spacecraft Relative State Estimation
Xi Liu
2016-09-01
Full Text Available A new algorithm called maximum correntropy unscented Kalman filter (MCUKF is proposed and applied to relative state estimation in space communication networks. As is well known, the unscented Kalman filter (UKF provides an efficient tool to solve the non-linear state estimate problem. However, the UKF usually plays well in Gaussian noises. Its performance may deteriorate substantially in the presence of non-Gaussian noises, especially when the measurements are disturbed by some heavy-tailed impulsive noises. By making use of the maximum correntropy criterion (MCC, the proposed algorithm can enhance the robustness of UKF against impulsive noises. In the MCUKF, the unscented transformation (UT is applied to obtain a predicted state estimation and covariance matrix, and a nonlinear regression method with the MCC cost is then used to reformulate the measurement information. Finally, the UT is adopted to the measurement equation to obtain the filter state and covariance matrix. Illustrative examples demonstrate the superior performance of the new algorithm.
Behavior of plywood and fiberglass steel composite tube structures subjected to impact loading
Armaghani, Seyamend Bilind
Paratransit buses are custom built as the major vehicle manufacturer produces the custom built passenger cage installed on the chassis for the Paratransit bus. In order for these Paratransit bus members to be sufficient, they have to be evaluated for crashworthiness and energy absorption. This has prompted Florida Department of Transportation (FDOT) to fund research for the safety evaluation of Paratransit busses consisting of crash and safety analysis. There has been a large body of research done on steel subjected to static loads, but more research is needed for steel applied under dynamic loading and high speeds in order to improve crashworthiness in events such as rollovers and side impacts. Bare steel Hollow Structural Section (HSS) tubing are used a lot as structural members of Paratransit buses because of their lightness and progressive buckling under loading. The research will be conducted on quantifying the tubing's behavior under bending by conducting static three point bending and impact loading tests. In addition to the bare tubing, plywood and fiberglass composites are investigated because they are both strong and lightweight and their behavior under dynamic loading hasn't been quantified. As a result, the main purpose of this research is to quantify the differences between the dynamic and static behavior of plywood steel composite and fiberglass steel composite tubing and compare these findings with those of bare steel tubing. The differences will be quantified using detailed and thorough experiments that will examine the composites behavior under both static and dynamic loading. These tests will determine if there are any advantages of using the composite materials and thus allow for recommendations to be made to the FDOT with the goal of improving the safety of Paratransit busses. Tensile tests were conducted to determine the material properties of the tested specimens. Before the static and dynamic experiments are run to investigate the differences
Wei, Ying
2015-01-01
Anchor hooking on a subsea pipeline has been investigated in this thesis. Anchor loads on pipelines is in general a rarely occurring event, however, the severity when it occurs could easily jeopardize the integrity of any pipeline. It is considered as an accidental load in the design of pipelines. Pipeline Loads, limit state criteria and anchor categories are defined by the DNV standards. For pipeline, DNV-OS-F101 (08.2012), Submarine Pipeline Systems is adopted. Offshore standard DNV-RP...
Macdonald, J. S. P.; Lavie, N.
2008-01-01
Although the perceptual load theory of attention has stimulated a great deal of research, evidence for the role of perceptual load in determining perception has typically relied oil indirect measures that infer perception from distractor effects on reaction times or neural activity (see N. Lavie, 2005. for a review). Here we varied the level of perceptual load in a letter-search task and assessed its effect oil the conscious perception of a search-irrelevant shape stimulus appearing in the pe...
Effective soil hydraulic conductivity predicted with the maximum power principle
Westhoff, Martijn; Erpicum, Sébastien; Archambeau, Pierre; Pirotton, Michel; Zehe, Erwin; Dewals, Benjamin
2016-04-01
Drainage of water in soils happens for a large extent through preferential flowpaths, but these subsurface flowpaths are extremely difficult to observe or parameterize in hydrological models. To potentially overcome this problem, thermodynamic optimality principles have been suggested to predict effective parametrization of these (sub-grid) structures, such as the maximum entropy production principle or the equivalent maximum power principle. These principles have been successfully applied to predict heat transfer from the Equator to the Poles, or turbulent heat fluxes between the surface and the atmosphere. In these examples, the effective flux adapts itself to its boundary condition by adapting its effective conductance through the creation of e.g. convection cells. However, flow through porous media, such as soils, can only quickly adapt its effective flow conductance by creation of preferential flowpaths, but it is unknown if this is guided by the aim to create maximum power. Here we show experimentally that this is indeed the case: In the lab, we created a hydrological analogue to the atmospheric model dealing with heat transport between Equator and poles. The experimental setup consists of two freely draining reservoirs connected with each other by a confined aquifer. By adding water to only one reservoir, a potential difference will build up until a steady state is reached. From the steady state potential difference and the observed flow through the aquifer, and effective hydraulic conductance can be determined. This observed conductance does correspond to the one maximizing power of the flux through the confined aquifer. Although this experiment is done in an idealized setting, it opens doors for better parameterizing hydrological models. Furthermore, it shows that hydraulic properties of soils are not static, but they change with changing boundary conditions. A potential limitation to the principle is that it only applies to steady state conditions
Concentrated loads on concrete
Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter
1997-01-01
This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are devel......This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas...
Concentrated loads on concrete
Lorenzen, Karen Grøndahl; Nielsen, Mogens Peter
1997-01-01
This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas are devel......This report deals with concentrated loads on concrete.A new upper bound solution in the axisymmetrical case of a point load in the center of the end face of a cylinder is developed.Based on previous work dealing with failure mechanisms and upper bound solutions, new approximate formulas...
Walt Wells
2008-01-01
Full Text Available Our objective in this paper is to solve a second order differential equation for a long, simply supported column member subjected to a lateral axial load using Heun's numerical method. We will use the solution to find the critical load at which the column member will fail due to buckling. We will calculate this load using Euler's derived analytical approach for an exact solution, as well as Euler's Numerical Method. We will then compare the three calculated values to see how much they deviate from one another. During the critical load calculation, it will be necessary to calculate the moment of inertia for the column member.
Vitaliy V. Chaban
2014-12-01
Full Text Available This research is devoted to analyzing the dynamic loads generated in the glove machine at reciprocating motion of knitting and intermediate carriages. Proposed is a method for determining the maximum dynamic loads in the glove machine carriages’ drive. It is noted that the dynamic loads reduction can be achieved by equipping the drive with energy accumulation and compensation units, in which quality it is expedient to use the cylindrical compression springs. The obtained dependence allows to determine the necessary stiffness of compression springs (energy accumulating and compensating units, at which the dynamic loads due to the carriages masses’ inertia can be almost completely eliminated.
Buffer gas loaded magneto-optical traps for Yb, Tm, Er and Ho
Hemmerling, Boerge; Drayna, Garrett K.; Chae, Eunmi; Ravi, Aakash; Doyle, John M.
2014-06-01
Direct loading of lanthanide atoms into magneto-optical traps (MOTs) from a very slow cryogenic buffer gas beam source is achieved, without the need for laser slowing. The beam source has an average forward velocity of 60-70\\;m\\;{{s}^{-1}} and a velocity half-width of \\sim 35\\;m\\;{{s}^{-1}}, which allows for direct MOT loading of Yb, Tm, Er and Ho. Residual helium background gas originating from the beam results in a maximum trap lifetime of about 80 ms (with Yb). The addition of a single-frequency slowing laser applied to the Yb in the buffer gas beam increases the number of trapped Yb atoms to 1.3\\left( 0.7 \\right)\\times {{10}^{8}} with a loading rate of 2.0\\left( 1.0 \\right)\\times {{10}^{10}}\\;atoms\\;{{s}^{-1}}. Decay to metastable states is observed for all trapped species and decay rates are measured. Extension of this approach to the loading of molecules into a MOT is discussed.
R.Nagendra Babu
2010-08-01
Full Text Available Geometric discontinuities cause a large variation of stress and produce a significant increase in stress. The high stress due to the variation of geometry is called as ‘stress concentration’. This will increase when the loads are further applied. There are many investigators who have studied the stress distribution around the notches, grooves, and other irregularities of various machine components. This paper analyses the effects of thermal and fatigue load on a steam turbine rotor under the operating conditions. Stresses due to thermal and dynamic loads of High Pressure Steam Turbine Rotor of 210MW power station are found in two stages. A source code is developed for calculating the nominal stress at each section of HPT rotor. Maximum stress is obtained using FEA at the corresponding section. Thermal and Fatigue Stress Concentration Factors at each section are calculated. It is observed that the SCFdue to the combined effect of thermal and dynamic loads at the temperatures beyond 5400C is exceeding the safe limits.
Rees, M. [Aerodyn Energiesysteme gmbH, Rendsburg (Germany)
1996-09-01
The Germanische Lloyd guideline allows calculations of load spectra in two fundamentally different ways. In the case of the so-called `simplified load spectra` the maximum amplitude of fluctuation of a load component is formed as {+-}75% of the average value of the purely aerodynamic loads of this component at rated wind conditions, together with an overlay of mass-related loads. The second method allowed in the GL guideline is the calculation of load spectra from simulation results in the time domain. For a number of average wind speeds the time-dependent characteristics of the load components are calculated taking account of the natural spatial turbulence of the wind. These are converted into load spectra using the rainflow method. In a parametric study the load spectra are calculated according to both methods and compared. The calculations are performed for turbines with rated powers of 100 kW to 2000 kW, with two and three blades, and also for stall-controlled and pitch-controlled turbines. The calculated load spectra are compared with each by means of 1 P fatigue equivalent load spectra. The influence of individual parameters is presented, as is the validity of the simplified load spectra. (au)
Glišić Mirko
2016-01-01
Full Text Available Introduction. Differences between the tooth and implant response to load can lead to many biological and technical implications in the conditions of occlusal forces. Objective. The objective of this study was to analyze load distribution in tooth/implant-supported fixed partial dentures with the use of resilient TSA (Titan Shock Absorber, BoneCare GmbH, Augsburg, Germany abutment and conventional non-resilient abutment using finite element method. Methods. This study presents two basic 3D models. For one model a standard non-resilient abutment is used, and on the implant of the second model a resilient TSA abutment is applied. The virtual model contains drawn contours of tooth, mucous membranes, implant, cortical bones and spongiosa, abutment and suprastructure. The experiment used 500 N of vertical force, applied in three different cases of axial load. Calculations of von Mises equivalent stresses of the tooth root and periodontium, implants and peri-implant tissue were made. Results. For the model to which a non-resilient abutment is applied, maximum stress values in all three cases are observed in the cortical part of the bone (maximum stress value of 49.7 MPa. Measurements of stress and deformation in the bone tissue in the model with application of the resilient TSA abutment demonstrated similar distribution; however, these values are many times lower than in the model with non-resilient TSA abutment (maximum stress value of 28.9 MPa. Conclusion. Application of the resilient TSA abutment results in more equal distribution of stress and deformations in the bone tissue under vertical forces. These values are many times lower than in the model with the non-resilient abutment.
GROWTH ANALYSIS AND ASSESSMENT OF PIG’S BIOLOGICAL MAXIMUM
Dragutin Vincek
2010-06-01
Full Text Available The aim of this study was to determine a mathematical model which can be used to describe the growth of domestic animals in an attempt to predict the optimal time of slaughter/weight or the development of body parts or tissues and estimate the biological maximum. The study was conducted on 60 pigs (30 barrows and 30 gilts in the interval between the age of 49 and 215 days. By applying the generalized logistic function, the growth of live weight and tissues were described. The observed gilts reached the inflection point in approximately 121 days (I = 70.7 kg. The point at which the interval of intensive growth starts was at the age of approximately 42 days, (TB=17.35 kg and the saturation point the pigs reached at the age of 200.5 days (TC=126.74 kg. The estimated biological maximum weight of gilts was 179.79 kg. The barrows reached the inflection point in approximately 149 days (I=92.2 kg. The point at which the intensive interval of growth starts was estimated at the age of approximately 52 days (TB=22.93 kg, and the saturation point the barrows reached at the age of 245 days (TC=164.8 kg. The estimated biological maximum weight of barrows was 233.25 kg. Muscle tissue of gilts reached the inflection point (I = 28.46 kg in approximately 110 days. The point at which the interval of intensive growth of muscle tissue starts (TB=6.06 kg was estimated at approximately 53 days, and the saturation point of growth (TC=52.25 kg the muscle tissue of gilts reached at the age of 162 days. The estimated maximum biological growth of muscle tissue in gilts was 75.79 kg. The muscle tissue of barrows reached the inflection point (I=28.78 kg in approximately 118 days, the point at which the interval of intensive growth starts (TB=6.36 kg at the age of approximately 35 days. The saturation point of muscle tissue growth in barrows (TC=52.51 kg was reached at the age of 202 days. The estimated maximum biological growth of muscle tissue in barrows was 75.74 kg. The
Zhang, Ming
Recent trends in the electric power industry have led to more attention to optimal operation of power transformers. In a deregulated environment, optimal operation means minimizing the maintenance and extending the life of this critical and costly equipment for the purpose of maximizing profits. Optimal utilization of a transformer can be achieved through the use of dynamic loading. A benefit of dynamic loading is that it allows better utilization of the transformer capacity, thus increasing the flexibility and reliability of the power system. This document presents the progress on a software application which can estimate the maximum time-varying loading capability of transformers. This information can be used to load devices closer to their limits without exceeding the manufacturer specified operating limits. The maximally efficient dynamic loading of transformers requires a model that can accurately predict both top-oil temperatures (TOTs) and hottest-spot temperatures (HSTs). In the previous work, two kinds of thermal TOT and HST models have been studied and used in the application: the IEEE TOT/HST models and the ASU TOT/HST models. And, several metrics have been applied to evaluate the model acceptability and determine the most appropriate models for using in the dynamic loading calculations. In this work, an investigation to improve the existing transformer thermal models performance is presented. Some factors that may affect the model performance such as improper fan status and the error caused by the poor performance of IEEE models are discussed. Additional methods to determine the reliability of transformer thermal models using metrics such as time constant and the model parameters are also provided. A new production grade application for real-time dynamic loading operating purpose is introduced. This application is developed by using an existing planning application, TTeMP, as a start point, which is designed for the dispatchers and load specialists. To
Essays in applied microeconomics
Davis, Lucas William
2005-11-01
The first essay measures the impact of an outbreak of pediatric leukemia on local housing values. A model of residential location choice is used to describe conditions under which the gradient of the hedonic price function with respect to health risk is equal to household marginal willingness to pay to avoid pediatric leukemia risk. This equalizing differential is estimated using property-level sales records from a county in Nevada where residents have recently experienced a severe increase in pediatric leukemia. Housing values are compared before and after the increase with a nearby county acting as a control group. The results indicate that housing values decreased 15.6% during the period of maximum risk. Results are similar for alternative measures of risk and across houses of different sizes. With risk estimates derived using a Bayesian learning model the results imply a statistical value of pediatric leukemia of $5.6 million. The results from the paper provide some of the first market-based estimates of the value of health for children. The second essay evaluates the cost-effectiveness of public incentives that encourage households to purchase high-efficiency durable goods. The demand for durable goods and the demand for energy and other inputs are modeled jointly as the solution to a household production problem. The empirical analysis focuses on the case of clothes washers. The production technology and utilization decision are estimated using household-level data from field trials in which participants received front-loading clothes washers free of charge. The estimation strategy exploits this quasi-random replacement of washers to derive robust estimates of the utilization decision. The results indicate a price elasticity, -.06, that is statistically different from zero across specifications. The parameters from the utilization decision are used to estimate the purchase decision using data from the Consumer Expenditure Survey, 1994-2002. Households
Lee, Chinwai; Lin, Hsiang Hsi; Oswald, Fred B.; Townsend, Dennis P.
1990-01-01
A computer simulation for the dynamic response of high-contact-ratio spur gear transmissions is presented. High contact ratio gears have the potential to produce lower dynamic tooth loads and minimum root stress but they can be sensitive to tooth profile errors. The analysis presented examines various profile modifications under realistic loading conditions. The effect of these modifications on the dynamic load (force) between mating gear teeth and the dynamic root stress is presented. Since the contact stress is dependent on the dynamic load, minimizing dynamic loads will also minimize contact stresses. It is shown that the combination of profile modification and the applied load (torque) carried by a gear system has a significant influence on gear dynamics. The ideal modification at one value of applied load will not be the best solution for a different load. High-contact-ratio gears were found to require less modification than standard low-contact-ratio gears. High-contact-ratio gears are more adversely affected by excess modification than by under modification. In addition, the optimal profile modification required to minimize the dynamic load (hence the contact stress) on a gear tooth differs from the optimal modification required to minimize the dynamic root (bending) stress. Computer simulation can help find the design tradeoffs to determine the best profile modification to satisfy the conflicting constraints of minimizing both the load and root stress in gears which must operate over a range of applied loads.
IMPACT OF AN UNDERSLUNG LOAD ON A HELICOPTER CONTROLLABILITY
2016-01-01
Full Text Available This article is aimed at finding the causes of controllability variations of a helicopter while transporting sling load.The maximum angular acceleration taken by the helicopter at similar controller displacement at different flight speeds was taken as a quantity characteristic of controllability efficiency to study the load impact on the helicopter cont- rollability.This article offers research results obtained with the use of the НеliСargо software. This software has proven to be a great tool for integrated research of the impact of an underslung load on the parameters of a helicopter controllability, and allows carrying out an analysis of the impact of an underslung load on the parameters of controllability under its dyna- mic behavior.The performed computational experiments have shown that the helicopter maximum angular acceleration with an underslung load significantly rises, as compared to a helicopter without cargo or a helicopter carrying the same load inside the cargo compartment. The data obtained during computational experiments corresponds to the results of analytical computations, and is in line with the literature based on the experience of helicopter flight operations.The cause of the variation in the helicopter controllability parameters during transportation of an underslung load has been found, that is - the underslung load considerably increases the main rotor thrust, due to sling load, as compared to a helicopter without cargo. When compared to a helicopter carrying a load inside the cargo compartment, this increased efficiency is mainly attributed to the fact that a helicopter with an underslung load has lower rotational inertia, since the load is not inside the cargo compartment, but outside.The obtained results can be used to improve flight manuals and flight personnel training publications, which could play a significant part in ensuring flight safety and security, and increasing the operational efficiency of